European Journal of Scientific Research - EuroJournals

European Journal of Scientific Research 

ISSN: 1450-216X Volume 14, No 3 July, 2006 

Editor-In-chief or e 

Adrian M. Steinberg, Wissenschaftlicher Forscher 

Editorial Advisory Board e 

Parag Garhyan, Auburn University 

Morteza Shahbazi, Edinburgh University 

Raj Rajagopalan, National University of 

Singapore 

Sang-Eon Park, Inha University 

Said Elnashaie, Auburn University 

Subrata Chowdhury, University of Rhode 

Island 

Ghasem-Ali Omrani, Tehran University of 

Medical Sciences 

Ajay K. Ray, National University of Singapore 

Mutwakil Nafi, China University of 

Geosciences 

Felix Ayadi, Texas Southern University 

Bansi Sawhney, University of Baltimore 

David Wang, Hsuan Chuang University 

Cornelis A. Los, Kazakh-British Technical 

University 

Jatin Pancholi, Middlesex University 

Teresa Smith, University of South Carolina 

Ranjit Biswas, Philadelphia University 

Chiaku Chukwuogor-Ndu, Eastern Connecticut 

State University 

John Mylonakis, Hellenic Open University 

(Tutor) 

M. Femi Ayadi, University of Houston-Clear 

Lake 

Emmanuel Anoruo, Coppin State University 

H. Young Baek, Nova Southeastern University 

Dimitrios Mavridis, Technological Educational 

Institure of West Macedonia 

Mohand-Said Oukil, Kind Fhad University of 

Petroleum & Minerals 

Jean-Luc Grosso, University of South Carolina 

Richard Omotoye, Virginia State University 

Mahdi Hadi, Kuwait University 

Jerry Kolo, Florida Atlantic University 

Leo V. Ryan, DePaul University 

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© EuroJournals Publishing, Inc. 2005

Contents 


Volume 14, No 3 July 2006 

Nutritive Evaluation of Some Trees and Browse Species from Scotland 311-318 

Odeyinka, S.M, Hector, B.L and Ørskov, E.R 

Determination of Sample Size 319-325 

Nadia Saeed, Muhammad Khalid Pervaiz and Muhammad Qaiser Shahbaz 

Model-Based Adaptive Chaos Control using Lyapunov Exponents 326-332 

Amin Yazdanpanah Goharrizi and Mehdi Semin 

Investigation of Complex Formation PDTC with Ni(II) in Physiological Conditions 333-338 

S. J. Fatemi , A. Badiei and A. Hooshmand 

Germination Studies in Selected Native Desert Plants of Kuwait 339-345 

Sameeha Zaman, Shyamala Padmesh, Narayan R. Bhat and Harby Tawfiq 

Age at Menarche, Current Premenstrual Syndrome and 

Health Risk Behaviour of Young People in Ibadan, Nigeria 346-353 

Moronkola, O.A and Aladesanyi, O.A 

The Assesment of Participation Decisionmaking of Head Nurses to 

According Training Programs and Supply Medical Equipment and 

Safty of Occupational Health and Alloceation Budget and Related 

between their Individual Variables at the Training Hospitals of Iran 

University of Medical Sciences 2005 354-358 

Maryam Nooritajer, Faezeh Nouroozinjad, Ezatjafarchla, Fatemeh and Hosseini 

Aetiology and Epidemiology of Sever Infantile Diarrhoea in Baghdad, Iraq 359-371 

E. N. Al-Kaissi, M. Makki and M. Al-Khoja 

Islam and Education from Religious Man’s Perspectives 372-387 

Nazenin Ruso 

Characterization of a Possible Modification of the Relation Rain-Flow in a 

Climatic Context of Variability: Case of the Catchment Area of the 

N’zi (Bandama) (Côte.D'ivoire) 388-400 

Amani Michel Kouassi, Koffi Fernand Kouame, Bi Tié Albert Goula, 

Jean-Emmanuel Paturel, Théophile Lasm and Jean Biemi 

Seedling Growth of Gmelina Arborea (Roxb) as Influenced by Crude Oil in Soil 401-406 

Agbogidi, O. M, Dolor, D. E and Okechukwu, E. M

A Comparative Analysis of Gibberellic Acid Content with Respect to 

Tuber Induction in Potato Plants Grown Under Differential Photoperiod 

and Temperature 407-416 

Ahmed Malkawi 

Research of the Characteristics of a Solar Panel Radiated with Со2 Laser, as 

Means for Injection on Fading Satellites 417-425 

M. Zamfirov 

Feature Selection Based on Statistical Analysis 426-433 

Nooritawati Md Tahir, Aini Hussain, Salina Abdul Samad, 

Hafizah Husain and Mohd Yusof Jamaluddin 

Sublingual Schwannoma in a Nigerian African-a Case Report 434-438 

Rahman G.A, Alabi.B.S, Afolabi.O.A, Bramoh.K.T and Buhari.M.O 

Health Impact Assessement of Multinational Corporations Oil Exploration in 

the Niger-Delta Region of Nigeria 439-446 

Ewhrudjakpor, Christian 

Development of Organic Carbon Sequestration Models for 

Dipterocarpus Turbinatus, Acacia Auriculiformis and Eucalyptus Camaldulensis 

and their Potentiality 447-455 

Md. Shahadat Hossain and Gouri Rani Banik


ISSN 1450-216X Vol.14 No.3 (2006), pp. 311-318 

© EuroJournals Publishing, Inc. 2006 


Nutritive Evaluation of Some Trees and Browse Species from 

Scotland 

Odeyinka, S.M 

Department of Animal Science, Faculty of Agriculture 

Obafemi Awolowo University, Ile-Ife, Nigeria 

Email:smodeyinka@yahoo.co.uk 

Hector, B.L 

The Macaulay Institute, Craigiebuckler 

Aberdeen AB15 8QH, UK 

Ørskov, E.R 

The Macaulay Institute, Craigiebuckler 

Aberdeen AB15 8QH, UK 

Abstract 

The nutritive value of twelve Scottish plants (trees, legumes and grasses): 1. Pinus 

sylvestris L., 2. Lolium perenne L., 3. Calluna vulgaris L., 4. Picea sitchensis (Bong.) 

Carr; 5. Chamaenerion angustifolium (L.) Scop., 6. Luzula sylvatica, 7. Pseudotsuga 

menziesii F. Mirb., 8. Fagus sylvatica L., 9. Vaccinum myrtillus L., 10. Brassica oleracea, 

11. Acer pseudoplatanus L., 12. Juncus effusus L. were determined using in vitro gas 

production, in sacco DM degradability and in vivo digestibility. 

Polyethylene glycol (PEG) was used in the gas production to determine presence of 

phenolic related antinutritive factor. Species had significant effect on in vitro gas 

production (P

Nutritive Evaluation of Some Trees and Browse Species from Scotland 312 

Introduction 

Nutrition is perhaps the most important consideration in livestock management. The nutritive value of 

a feed is essentially a function of the availability of its energy and nutrient contents. According to Van 

Soest (1983), nutritive value is multifaceted, but useful attributes of a feed are feed consumption and 

digestibility. Browse (shrubs and tree foliage) plays a significant role in providing fodder for ruminants 

in many parts of the world (Adugna et.al. 1997). Tree fodder is generally richer in protein and minerals 

and is used as a dry season supplement to poor quality natural pasture and or fibrous crop residues 

(Devendra, 1990; Kibbon and Orskov, 1993). 

In vitro methods for laboratory estimations and feed degradation are important tools for 

ruminant nutritionists. The Hohenheim in vitro gas test is extensively used for the estimation of in vivo 

digestibility and metabolizable energy for ruminants (Menke et al., 1979). Internationally, the gas test 

is of increasing interest because of the possibility of estimating the extent and rate of degradation in 

one sample by time series measurement of the accumulating gas volume (Blummel et al., 1990; 

Khazaal et al., 1993, Orskov, 2000). However, the presence of tannins and other phenolic compounds 

in a large number of nutritionally important shrubs and tree leave decrease their utilization as animal 

feed. In general, most browse species contain phenolic compounds that reduce digestibility and 

availability of protein, and contribute to unpalatability and reduced intake (Woodward and Reed, 1989; 

Kumar and Vaaithiyanaathan, 1990; Kibon and Ørskov, 1993). There have been several studies aimed 

at inactivating phenolic compounds using polyvinyl pyrolidone (PVP) or polyethylene glycol (PEG). 

Thus PEG has been used to adsorb plant phenolics during the extraction of enzymes because of its 

hydrophobic properties (Badran and Jones, 1965). A potential increase in in vitro (Kumar and 

Vaithiyanathan, 1990) and in vivo (Jones and Mangan, 1977) digestibility of tannin rich feeds by the 

addition of PEG-4000 has also been reported. 

While the nutritional potential and limitations of many tropical and Mediterranean browse 

species have been documented, comparatively little has been done on temperate trees species. Thus, the 

objective of this study was to assess the nutritive value of some tree species from Scotland based on 

their in vitro gas production, DM degradability in sacco and in vivo digestibility. 

Materials and Methods 

The forages used in the study were 1. Pinus sylvestris L. (Scots pine), 2. Lolium perenne L. (grass) 

/Trifolium repens L. (Clover) mixture, 3. Calluna vulgaris L. (Heather), 4. Picea sitchensis (Bong.) 

Carr. (Sitka spruce), 5. Chamaenerion angustifolium (L.) Scop. (Roseby willowherb), 6. Luzula 

sylvatica (Great Woodrush), 7. Pseudotsuga menziesii F. Mirb. (Douglas fir), 8. Fagus sylvatica L. 

(Beech), 9. Vaccinum myrtillus L. (Vaccinum), 10. Brassica oleracea (Cabbage), 11. Acer 

pseudoplatanus L. (Sycamore), 12. Juncus effusus L. (Soft Rush) 

Most of the tree leaves and browse species were hand harvested at Macaulay Research 

Institute's experimental station at Glensaugh, Aberdeenshire, Scotland. The L. perenne was machine 

harvested while the B. oleracea was purchased from a local farmer. The samples were oven dried at 

70ºC for 48 hours and milled using a 1-mm screen. 

In vitro gas production 

In vitro gas production was measured using the method described by Blummel and Orskov (1993) by 

incubating the forage samples with buffer and rumen fluid and recording the volume of gas produced 

over time. Measurements were made after 3, 6, 12, 24, 48, 72 and 96 hours of incubation. Analysis was 

carried out in triplicate in the presence and absence of 200mg PEG, molecular weight 4000 (Sigma- 

Aldrich Company Ltd, Poole, Dorset, UK). The gas syringes were incubated by suspension from a rack 

fitted above a water bath. The rumen fluid was taken from two sheep, fitted with permanent rumen 

cannulae, receiving a diet of dried L. perenne pellets and hay.

313 Odeyinka, S.M, Hector, B.L and Ørskov, E.R 

Estimations of rumen degradability were made using the nylon bag technique described by 

Ørskov et al. (1980). The nylon bags used were 8cm x 14cm, 40 to 60-micron pore size (IFRU, The 

Macaulay Institute, Aberdeen, UK). Duplicate samples were incubated in 2 different sheep receiving 

the same diet as above. The following incubation times were used: 4, 8, 16, 24, 48, 72, and 96 hours. 

The results of the experiments were analysed using “Fitcurve” macro (Chen, X.B., 1995. IFRU, 

The Macaulay Institute, Aberdeen, UK) for Microsoft Excel. The program is a utility for processing 

data of feed degradability or in vitro gas production, it fits the data to the exponential equation 

p=a+b(1-e -ct ) developed by Ørskov and McDonald (1979). For degradability characteristics, p is the 

percentage degraded at time t, a is the intercept of the line at time zero, b is the insoluble but 

degradable fraction, therefore a+b is the potential degradability and c is the rate of degradation. While 

this equation was originally developed for protein supplements in which the intercept was also an 

approximate expression of solubility, this is not the case for trees and shrubs due to the occurrence of a 

lag phase or a period in which there is no net disappearance of the insoluble but fermentable substrate 

(Ørskov and Ryle, 1990). Accordingly, A is solubility and small particle loss, B is the insoluble but 

fermentable fraction (B=(a+b)–A). For in vitro gas production, the data is fitted to the same equation, p 

is the volume of gas produced at time t, a is the intercept of the line at time zero, b is the potential gas 

production and c is the rate constant (Ørskov and Ryle, 1990). 

In vivo digestibility 

In this experiment, 12 mature sheep were used. Animals were housed in metabolism crates. Total 24hour 

urine and faeces collections were made throughout the experiment by means of chutes and 

separators fitted underneath the metabolism crates. The experiment consisted of individual 

experimental periods, separated by periods of 14 days. During each experimental period, animals were 

randomly allocated to different experimental treatments in a partial Latin square design. 

Animal 1 Animal 2 Animal 3 Animal 4 Animal 5 Animal 6 

Period 1 A B A+B+C D E D+E+F 

Period 2 B A+B B+C E D+E E+F 

Period 3 C C A+C F F D+F 

Period 4 A+B+C B+C A D+E+F E+F D 

Period 5 A+B A A+B D+E D D+E 

Period 6 B+C A+C B E+F D+F E 

Period 7 A+C A+B+C C F+D D+E+F F 

Animal 7 Animal 8 Animal 9 Animal 10 Animal 11 Animal 12 

Period 1 G H G+H+I J J J 

Period 2 H G+H H+I K K K 

Period 3 I I G+I L L L 

Period 4 G+H+I H+I G J+K+L J+K+L J+K+L 

Period 5 G+H G G+H J+K J+K J+K 

Period 6 H+I G+I H K+L K+L K+L 

Period 7 I+J G+H+I I L+J L+J L+J 

A letter (A, B, C, D, etc) represents an individual plant material. 

Statistical Analysis: The results were subjected to statistical analysis using GENSTAT 5 

Release 4.1 software package. Analysis of variance was done to detect differences between treatments. 

Differences between treatments were analysed using means across replications. Least significant 

difference (LSD) test was used to compare treatment means


Results and Discussion 

Table 1 shows the in vitro gas production characteristics of the different Scottish forage species. As 

expected, gas production increased with the duration/length of incubation (Fig. 1 and Table 2). Species 

and PEG had significant effect on in vitro gas production (P L. 

perenne > F. sylvatica >A. pseudoplatanus > C. angustifolium > C. vulgaris J. effusus > P. sylvestris 

> L. sylvatica > P. menziesii > P. sitchensis >V. myrtillusi. There was no significant difference in gas 

production of L. perenne and A. pseudoplatanus and also P.sylvestris and J. effuses at the 96hr . There 

was significant increase in gas production with the addition of PEG (P


Gas Production (ml) 

60 

50 

40 

30 

20 

10 

0 

Figure 1: In vitro gas production of the leaves of Scottish plant species 

0 20 40 60 80 100 

Hours 

Table 2: Effect of PEG on in vitro gas production of Scottish plants 

Fagus sylvatica 

Brassica oleraceae 

Pseudotsuga 

menziesii 

Lolium perenne 

Calluna vulgaris 

Chamaenerion 

angustifolium 

Luzula sylvatica 

Pinus sylvestris 

Picea sitchensis 

Acer pseudoplatanus 

Vaccinium myrtillus 

Juncus effusus 

Time, h 

Species s 3 6 12 24 48 72 96 

Fagus sylvatica 3.56 a 6.87 a 11.70 a 21.75 a 33.69 a 36.03 a 37.38 a 

Fagus sylvatica + PEG 4.86 b 9.75 b 15.58 b 26.30 b 33.90 a 40.12 b 42.86 b 

Brassica oleraceae 7.92 a 18.11 a 34.81 a 46.98 a 55.75 a 59.15 a 60.85 a 

Brassica oleraceae + PEG 7.93 a 19.09 b 36.71 b 49.05 b 57.56 b 61.38 b 63.44 b 

Pseudotsuga menziesii 2.45 a 6.01 a 12.17 a 18.89 a 23.07 a 25.43 a 25.98 a 

Pseudotsuga menziesii+PEG 4.05 b 8.66 b 14.76 b 21.15 b 25.29 b 27.09 b 27.09 b 

Lolium perenne 3.80 a 9.10 a 21.10 a 31.74 a 39.80 a 43.30 a 44.90 a 

Lolium perenne + PEG 3.81 a 9.53 a 21.93 a 33.53 a 41.23 a 44.13 a 45.22 a 

Calluna vulgaris 3.30 a 6.90 a 12.57 a 22.38 a 27.43 a 29.54 a 30.92 a 

Calluna vulgaris + PEG 4.31 b 9.19 b 15.28 b 25.97 b 30.65 b 31.64 b 32.98 b 

Chamaenerion angustifolium 2.21 a 4.44 a 10.14 a 19.18 a 23.98 a 25.82 a 26.10 a 

Chamaenerion angustifolium + PEG 3.02 b 6.89 b 15.58 b 25.39 b 32.08 b 34.46 b 34.74 b 

Luzula sylvatica 2.69 a 5.67 a 11.22 a 19.48 a 24.96 a 27.56 a 28.37 a 

Luzula sylvatica EG 3.04 a 6.38 a 12.63 a 21.38 a 26.45 a 28.85 a 29.68 a 

Pinus sylvestris 2.75 a 5.80 a 12.30 a 21.85 a 26.63 a 27.91 a 28.46 a 

Pinus sylvestris PEG 3.27 b 6.83 b 13.54 b 22.99 b 27.99 b 29.54 b 30.35 b 

Picea sitchensis 2.97 a 6.23 a 10.18 a 16.04 a 19.91 a 20.90 a 21.44 a 

Picea sitchensis + PEG 4.07 b 8.71 b 14.85 b 19.92 b 23.27 b 24.81 b 24.81 b 

Acer pseudoplatanus 2.46 a 4.66 a 8.65 a 18.39 a 32.74 a 41.34 a 45.24 a 

Acer pseudoplatanus + PEG 2.73 b 4.67 a 8.66 a 18.42 a 32.96 a 41.40 a 45.44 a 

Vaccinum myrtillus 1.86 a 4.27 a 8.67 a 14.42 a 18.76 a 20.53 a 21.06 a 

Vaccinum myrtillus + PEG 2.69 b 6.75 b 13.10 b 19.75 b 23.87 b 25.94 b 26.48 b 

Juncus effusus 1.08 a 2.73 a 5.60 a 16.36 a 26.75 a 34.79 a 37.50 a 

Juncus effuses + PEG 1.10 a 3.04 a 6.49 b 18.74 b 31.18 b 37.12 b 39.59 b 

SE Difference 0.09 0.15 0.23 0.32 0.47 0.51 0.53 

Means with different superscripts for the same species in the same column and the same hour are statistically different 

(P L. perenne >A. pseudoplatanus


> L. sylvatica > P. sylvestris > J. effusus > V. myrtillus > P. sitchensis > P. menziesii > C. vulgaris 

>F. sylvatica (Table 4). 

Table 3: Degradation characteristics of the Scottish plant species as described by p = a + b (1-e -ct ) 

Species a b c RSD A B (A+B) 

Fagus sylvatica 19.4 11.3 0.0325 0.447 16.4 14.3 30.7 

Brassica oleracea 37.2 62.8 0.1077 5.839 62.3 37.7 100 

Pseudotsuga menziesii 26.3 19.7 0.0516 1.643 32.7 13.3 46.0 

Lolium perenne 11.5 80.4 0.0671 6.114 32.3 60.3 92.6 

Calluna vulgaris 12.0 31.7 0.0374 1.443 10.4 32.1 42.5 

Chamaenerion angustifolium 6.5 91.5 0.0440 8.352 24.2 73.8 98.0 

Luzula sylvatica 10.0 56.2 0.0178 4.117 16.1 50.0 66.1 

Pinus sylvestris 18.7 41.1 0.0366 2.193 20.9 38.9 59.8 

Picea sitchensis 27.6 18.8 0.0401 1.303 24.5 21.9 46.4 

Acer pseudoplatanus 10.9 62.5 0.0831 3.809 27.5 45.9 73.4 

Vaccinum myrtillus 18.3 37.9 0.0387 3.717 18.6 37.6 56.2 

Juncus effusus 7.5 59.2 0.0179 1.608 16.7 50.0 66.7 

a = solubility and small particle loss 

b = insoluble but fermentable fraction 

c = rate constant. 

A = Washing loss (%) 

B = Degradation of water insoluble (%) 

A+B = Potential degradability (%) 

Table 4: Ranking of Scottish species according to in vitro gas production, DMD and in vivo digestibility 

Species Ranking of 48hr invitro Ranking of 48hr Ranking of in vivo 

Gas 

DMD 

digestibilty 

Fagus sylvatica 3 (33.69) 12 (27.70) 8 (36.81) 

Brassica oleracea 1 (55.75) 1 (100.00) 1 (77.83) 

P. menziesii 10 (23.07) 10 (43.79) 9 (35.38) 

Lolium perenne 2 (40.61) 3 (87.84) 2 (71.96) 

Calluna vulgaris 6 (27.43) 11 (38.65) 6 (45.15) 

Chamaenerion angustifolium 5 (32.08) 2 (90.61) 10 (34.66) 

Luzula sylvatica 9 (26.45) 5 (54.77) 5 (47.72) 

Pinus sylvestris 8 (26.63) 6 (53.64) 12 (33.28) 

Picea sitchensis 11 (19.91) 9 (43.82) 3 (58.13) 

Acer pseudoplatanus 4 (32.74) 4 (70.91) 11 (34.40) 

Vaccinum myrtillus 12 (18.76) 8 (50.90) 7 (36.88) 

Juncus effusus 7 (26.75) 7 (50.93) 4 (48.44) 

The ranking is shown from the highest to the lowest (1 to 12) with the actual values in brackets 

Species had significant effect on the in vivo DM digestibility of the forage species. B. oleracea 

had the highest % (77.83) in vivo DM digestibilty as observed with in vitro gas production and in 

sacco DM degradability. P. sylvestris had the lowest in vivo digestibility (33.28%). The ranking of the 

forages in terms of in vivo DM digestibility was B. oleracea (77.83%) > L. perenne > (72.00%) > P. 

sitchensis (58.13%) > J. effusus (48.44) > L. sylvatica (47.72) > C. vulgaris (45.15%) > V. myrtillus 

(36.88%) > F. sylvatica (36.81%) > P. menziesii (35.38%) > C. angustifolium (34.66%) > A. 

pseudoplatanus (34.40) > P. sylvestris (33.28%). The ranking of the species according to in vitro gas 

production, DMD and in vivo digestibility is shown in Table 4. Some plant species (B. oleracea, P. 

menziesii and L. perenne) showed consistency / position in the three rankings. 

There was a high positive correlation co-efficient between gas production and in sacco. DM 

degradability at both 48hr and 72hr (0.72 and 0.71 respectively). The correlation co-efficient of the 

relationship between 12hr in vitro gas production and in vivo digestibility was 0.71 while that of 16hr 

in sacco. DM degradability and in vivo digestibility was 0.71. The correlation co-efficient of 48hr in


vitro gas production and in vivo digestibility was 0.65 while that of 48hr in sacco. DM degradability 

and in vivo digestibility was 0.51. Either in vitro gas or Dmd can be used to predict in vivo digestibility. 

The increase in gas production with the addition of PEG (P


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fibre composition and levels of extractable poly phenols in Greek browse: Effects on in vitro 

gas production and in sacco DM degradation. J. Sci. Food Agric., 63: 237-244 

[9] Kibbon, A. and Ørskov, E.R. (1993). The use of degradation characteristics of browse plants to 

predict intake and digestibility by goats. Anim. Prod. 57: 247- 251. 

[10] Kumar, R. and Vaithiyanathan, S. (1990). Occurrence, nutritional significance and effect on 

animal productivity of tannins in tree leaves. Anim. Feed Sci. Tech., 30: 21-38. 

[11] Menke, K., Raab, L., Salewski, A., Steingass, H., Fritz, D. and Schneider, W. (1979). The 

estimation of digestibility and metabolizable energy content of ruminant feedstuffs from the gas 

production when they are incubated with rumen liquor in vitro. J. Agric. Sci., Camb. 3: 217- 

222. 

[12] Odeyinka, S.M., Hector, B.L., Ørskov, E.R. (2003). Evaluation of the nutritive value of the 

browse species Gliricidia sepium (Jacq). Walp, Leucaena leucocephala (Lam.) de Wit. and 

Cajanus cajan (L.) Millsp from Nigeria. Journal of Animal and Feed Sciences, 12: 341-349 

[13] Ørskov, E. R. (2000). New concepts of feed evaluation for Ruminants with Emphasis on 

Roughages and Feed intake. Asian - Australian J. Anim. Sci 13: 128-136 

[14] Ørskov , E.R and McDonald, I., (1979). The estimation of protein degradability in the rumen 

from incubation measurements weighted according to the rate of passage. J. Agric. Sci., Camb. 

92: 499-503. 

[15] Ørskov E.R., Hovell F.D.DeB., Mould F., 1980. The use of the nylon bag technique for the 

evaluation of feedstuffs. Trop. Anim. Prod. 5, 195-213 

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degradation characteristics of roughages. Animal Production 46: 29-34 

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av Norske Formidler. K.K. Heje Lommehandbok, P. F. Steensballes Forlag. 

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browse: a summary of research conducted at ILCA. ILCA Bull. 35: 2-11


ISSN 1450-216X Vol.14 No.3 (2006), pp. 319-325 



Determination of Sample Size 

Nadia Saeed 

Department of Statistics, GC University (GCU) 

Lahore (Pakistan) 

E-mail: nadia_gcu@yahoo.com 

Muhammad Khalid Pervaiz 

Chairperson, Department of Statistics 

GC University (GCU), Lahore (Pakistan) 

E-mail: drkhalidpervaiz@hotmail.com 

Muhammad Qaiser Shahbaz 

Department of Statistics, GC University (GCU) 

Lahore (Pakistan) 

E-mail: drshahbaz@gcu.edu.pk 

Abstract 

The sample size determination is one of the most frequent problems in the 

discipline of Statistics. Although standard formulae are available for determining sample 

size in many situations, yet specific methodology is lacking. The purpose of the paper is to 

highlight the factors involved in determining a desirable sample size for a research project. 

The paper offers the brief review of determining the sample size under varying situations. 

Some new formulae are also developed with special reference of cost function and degree 

of affordable error. 

Key Words: Sample size, error, clinical trials, power analysis and cost function. 

1. Introduction 

The size of the sample is not only an essential element in every statistical procedure but it is also an 

item of great economic importance. In a sample survey, a statistician must determine the sample size. 

Statistical studies (surveys, experiments, observational studies, etc.) are always better when they are 

carefully planned. Good planning has many aspects. The study must be of adequate size, relative to the 

goals of the study. Sample size is important for economic reasons: An under-sized study can be a waste 

of resources for not having the capability to produce useful results, while an over-sized one uses more 

resources than are necessary (Mace, 1964; Kraemer & Thiemann, 1987; Cohen, 1988; Desu & 

Raghavarao, 1990; Lipsey, 1990; Shuster, 1990; and Odeh & Fox, 1991). 

The points to be considered while selecting a sample size are: 

i) Parameter: The population parameters to be estimated like mean the difference between 

means or proportion. 

ii) Variance: The samples are taken to form estimates of some characteristics of interest, like 

determination of mean in simple random sampling, stratified random sampling and cluster 

sampling. Most of the work has been done to determine the sample size based on precision to

Determination of Sample Size 320 

minimize the variance. (Greenland, 1988; Samuels, 1992; Buderer, 1996; Satten & Kupper, 

1990; Streiner, 1994 and Beal, 1989). 

iii) Issues and Prior Information: If the process has been studied before, then the prior 

information can be used to reduce sample sizes. This can be done by using prior mean and 

variance estimates and by stratifying the population to reduce variation within groups. Increase 

in sample size may reduce the sampling error but may cause increase in non-sampling error. 

iv) Clinical Trials: At the planning stage of a clinical trial a key question is "How many patients 

do we need?” This requires a sample size that ensures sufficient statistical power to detect a 

clinically relevant improvement. Sample size must be planned carefully to ensure that the 

research time, patient effort & support and costs invested in any clinical trial are not wasted. 

v) Power Analysis: power analysis and sample size estimation is an important aspect of 

experimental design, because without these calculations, sample size may be too high or too 

low. If sample size is too low, the experiment will lack the precision to provide reliable answers 

to the questions it is investigating. If sample size is too large, time and resources will be wasted, 

often for minimal gain. 

vi) Cost: The cost of sampling issue helps to determine how precise the estimate should be. When 

choosing sample sizes, it is required to select risk values (affordable error). If the decisions 

made from the sampling activity are very valuable, then these will have low risk values and 

hence larger sample sizes. So some cost functions in different situations have been discussed. 

Choosing the sample size is a problem faced by anyone doing a survey of any type. ‘What 

sample size do I need?’ is one of the most frequently asked questions to the statisticians. The response 

always starts “It depends on...” The sample size must depend on what you want to know about and 

how well you want to know about it. In order to make rational sample size choices, both the quantities 

to be estimated and the precision required must be specified. 

Sample-size planning is very important and almost always difficult. It requires care in eliciting 

scientific objectives and in obtaining suitable quantitative information prior to the study. Successful 

resolution of the sample-size problem requires the close and honest collaboration of statisticians and 

subject-matter experts (Russell, 2001). 

Sample-size problems are context-dependent. For example, how important it is to increase the 

sample size to account for such uncertainty depends on practical and ethical criteria. Moreover, sample 

size is not always the main issue; it is only one aspect of the quality of a study design (Russell, 2001). 

The objective of the paper is to mention available literature relevant to the determination of 

sample size under various situations and to develop new formulae with reference to cost and affordable 

error. 

2. Sample size Estimation 

In this Section a review of above mentioned points is given with reference to estimating parameters, 

right variance, issues of interest, clinical trials, effect size, and power analysis. 

2.1. Parameters 

Chochran (1977) had given the simplest case for determination of sample size is concerned with 

infinite normal population with known variance. Desu and Raghavarao (1990) had provided brief 

review on sample size methodology. Further more the paired sample approach is employed by Dupont, 

(1988); Parker & Bregman, (1986); Nam, (1992); Lu & Bean, (1995); Lachenbruch, (1992); Lachin, 

(1992); Royston, (1993); Nam, (1997). A brief review has been given in literature to determine the 

sample size for the tests of proportions by Chochran, 1977; Casagrande, Pike & Smith, 1978; Feigl, 

1978; Haseman, 1978; Fleiss, 1981; Lemeshow, Hosmer & Klar, 1988; O’Neill, 1984; Thomas, 1992; 

Whitehead, 1993 and Gordon & Watson, 1996 for infinite population.

321 Nadia Saeed, Muhammad Khalid Pervaiz and Muhammad Qaiser Shahbaz 

2.2. Variance 

Another situation exists when someone is interested to find the right variance (Birkett & Day, 1994; 

Gould, 1995; Browne, 1995; Shih & Zhao, 1997) since some of the power functions usually involve 

parameters unrelated to the hypotheses. Most notably, they often involve one or more variances. For 

instance we need to know the residual variance of the measurements in the planned two-sample 

experiments, there may be substantial uncertainty in variance estimates obtained from historical or 

pilot data. There is some literature on dealing with variation in pilot data; a good starting point is 

Taylor and Muller (1995). Also, Muller and Benignus (1992) and Thomas (1997) discuss various 

simpler ways of dealing with these issues, such as sensitivity analyses. 

2.3. Issues and Prior Information 

At times the researcher has no choice about sample size. Often a study has limited budget. Sample size 

determination is an important issue because not all sample-size problems are the same, nor is sample 

size equally important in all studies. For example, the ethical issues in an opinion poll are very 

different from those in a medical experiment, and the consequences of an over or under-sized study 

also differ. Additional complications can hold for attribute data due to failures of asymptotic tests and 

inability to achieve a stated size due to discreteness or unusual situations such as inferences about rare 

attributes (Wright, 1997) and in case of Poisson and logistic regression (Whittemore, 1981; Hsieh, 

1989; Flack & Eudey, 1993; Bull, 1993 and Signorini, 1991). There are numerous articles, especially 

in biostatistics journals, concerning sample-size determination for specific tests like tests of continuous 

variables (Cohen, 1969; Pearson & Hartley, 1970 and Day & Graham, 1991). The extent to which 

sample size is adequate or inadequate in published studies provided by Freiman, Chalmers, Smith, and 

Kuebler, (1986). They worked on the importance of beta, the type-II error and sample size in the 

design and interpretation of the randomized controlled trial. Sample size determination can be done 

with the help of softwares. There is a growing amount of software for sample-size determination, 

including Query Advisor (Elashoff, 2000), PASS (Hintze, 2000), UnifyPow (O’Brien, 1998), and 

Power and Precision (Borenstein, 1997). Similarly Web resources include a comprehensive list of 

power-analysis software and online calculators (Thomas, 1998; Lenth, 2000). Wheeler (1974) provided 

some useful approximations for use in linear models; Castelloe (2000) gave an up-to-date overview of 

computational methods. 

Though it is an important issue with respect to Statistics, social sciences and natural sciences 

but there is surprisingly small amount of published literature. One step in the sample size problem 

requires eliciting an effect size of scientific interest. It is not up to statistical consultant to decide this; 

however, it is his responsibility to try to elicit this information from the researchers involved in 

planning the study. Boen & Zahn (1982) discussed some of the human dynamics involved in 

discussing sample size (mostly as distinct from effect size). They suggested asking directly for an 

upper bound on sample size, relating that most clients will respond readily to this question. 

2.4. Clinical Trials 

Adequate sample size can help to ensure academically interesting result, whether or not a statistically 

significant difference is eventually found in the study (Eng & Siegelman, 1997). There is a need to 

know that how certain study design characteristics affect sample size and how to calculate sample size 

for several simple study designs, which are discussed in different scientific fields especially in clinical 

trials (Eng, 2003). An inadequate sample size also has ethical implications. If a study is not designed to 

include enough individuals to adequately test the research hypothesis, then the study unethically 

exposes individuals to the risks and discomfort of the research even though there is no potential for 

scientific gain. Although the connection between research ethics and adequate sample size has been 

recognized for at least 25 years (Newell, 1978), the performance of clinical trials with inadequate


sample sizes remains widespread (Halpern, Karlawish & Berlin, 2002). So Rosner, (2000) described 

some Practical Consequences of Mathematical Properties. 

2.5. Power Analysis 

In sample size calculations, appropriate values for the smallest meaningful difference and the estimated 

SD are often difficult to obtain. In this case, power refers to the sensitivity of the study to enable 

detection of a statistically significant difference of the magnitude observed in the study. This activity, 

known as retrospective power analysis, is sometimes performed to aid in the interpretation of the 

statistical results of a study. If the results were not statistically significant, the investigator might 

explain the result as being due to a low power. So a lot of work is available in literature on power 

analysis by Detsky & Sackett (1985); Lubin & Gail (1990); Roebruck & Kuhn (1995); Thomas (1997); 

Castelloe (2000); Lenth (2001); Hoenig & Heisey (2001); Feiveson (2002). 

3. Cost Function and Degree of Affordable Error 

In this section, some new formulae for estimating sample size by changing affordable error in cost 

function have been developed. 

Let us have a cost function 

C C0 

C1n 

+ = 

Where ‘ C ’ is total cost, C 0 is overhead cost and C 1 is cost per unit. 

2 

Further suppose that the affordable error is of the form ε ( y − Y ) 

The expected loss for a sample of size ‘n’ will be: 

2 

S ( n) 

= E[ 

C] 

+ E ε ( y − Y ) 

2 

εS 

S( 

n) 

= C0 

+ C1n 

+ 

n 

2 

2 S 

Where E( 

y − Y ) = 

n 

After partially differentiating S (n) with respect to ‘n’ we can get: 

2 

1/ 

2 

1 ⎟⎟ 

⎛ εS 

⎞ 

n = ⎜ 

⎝ C ⎠ 

Similarly if error function is changed to ε y − Y with the similar cost function, then sample 

size can be determined as: 

⎛ 2εS 

⎞ 

n = ⎜ 

5 ⎟ 

⎝ C1 

⎠ 

2 / 3 

Acknowledgements 

The authors would like to thank Prof. Dr. Khalid Aftab, Vice Chancellor GCU for his anonymous 

support behind all the research activities in GC University, Lahore (Pakistan).


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ISSN 1450-216X Vol.14 No.3 (2006), pp. 326-332 



Model-Based Adaptive Chaos Control using Lyapunov 

Exponents 

Amin Yazdanpanah Goharrizi 

Department of Electrical Engineering 

K. N. Toosi University of Technology 

Tehran, Iran 

Mehdi Semin 

Department of Electrical Engineering 

Tabriz University, Tabriz, Iran 

E-mail: yazdanpanah@ee.kntu.ac.ir 

Abstract 

A model-based approach to adaptive control of chaos in non-linear chaotic discrete 

time systems is presented. In the case of unknown or time varying chaotic plants, the 

Lyapunov exponents may vary during the plant operation. In this paper, an effective 

adaptive strategy is proposed for on-line identification of Lyapunov exponents. The control 

aim is that the plant output changes in accordance with the output of the linear desired 

model. Also, a nonlinear observer for estimation of the states is proposed. Simulation 

results are provided to show the effectiveness of the proposed methodology. 


The analysis and control of chaotic behavior in dynamical systems has been widely investigated in 

recent years [1], [2], [3], [4] and [5].Also, Lyapunov exponents have been used to characterize and 

quantify the chaoticity of complex dynamical systems [6], and the computation of the Lyapunov 

exponents for nonlinear dynamical systems is an effective tool in this respect [7]. In [8], a model-based 

approach for anticontrol of some discrete-time systems is proposed and in this paper, a reverse method 

for control of chaotic systems is presented and also, a new method to adaptive control of chaos via 

adaptive calculation of Lyapunov exponents is introduced. The adaptive calculation of Lyapunov 

exponents proposed in [9-10-11], greatly facilities the design of adaptive chaos control. Thus, a 

generalized adaptive algorithm recursive least square for estimation of Lyapunov exponents is 

developed when the parameters of the system change abruptly. We use an efficient QR based method 

for the computation of Lyapunov exponents [12]. Then, if the maximum Lyapunov exponent becomes 

positive it's indicates the chaotic behavior and the control aim is that the plant output changes in 

accordance with the output of the linear desired model. So, the behavior of the closed-loop system 

depends on the linear model and it can be periodic or tends to zero after controlling. With the above 

strategy and adaptive calculation of Lyapunov exponents an efficient methodology for adaptive chaos 

control is presented. Also, a nonlinear observer is proposed when the sate of nonlinear chaotic plant are 

not available. Finally, simulation results for Henon map with time varying parameters are provided to 

show the effectiveness of the proposed methodology.

Model-Based Adaptive Chaos Control using Lyapunov Exponents 327 

2. Adaptive Estimation of Lyapunov Exponents 

Consider a nonlinear discrete-time dynamical system given by 

n 

⎪⎧ 

x( 

k + 1) 

= f [ x( 

k)] 

x( 

k) 

∈ R 

⎨ 

⎪⎩ x0 

− given 

(1) 

Where f is assumed to be continuously differentiable, at least locally in a region of interest 

and k = 0, 

1,... 

is the number of the sampling instants. Each of the scalar state variables in the nonlinear 

discrete-time dynamical system given by equation (1), can be rewritten in the following form 

T 

x j ( k + 1) 

= ϕ 1 j ( k) 

θ1 

+ ϕ2 

j ( k) 

θ 2 + ... + ϕij 

( k) 

θi 

= ϕ j ( k) 

θ j k = 0, 

1,... 

j = 1,..., 

n 

, 

, 

Where, x j are the scalar state variables, θ ij s are parameters to be determined, and ϕ ij s are 

known functions that may depend on other known variables. The vectors 

T 

ϕ ( k) 

= [ ϕ ( k) 

ϕ ( k) 

... ϕ ( k)] 

j 

1 j 

2 j 

ij 

θ j = ( θ1 

j θ2 

j ... 

T 

θij 

) 

(2) 

have also been introduced. By invoking the recursive least square (RLS) algorithm, the parameters of 

the model in (2) can be updated recursively [13]: 

ˆ ˆ 

T 

θ ( ) ( 1) 

( )[ ( ) ( ) ˆ 

j k = θ j k − + K k x j k −ϕ 

j k θ j ( k −1)] 

(3) 

Where 

T 

−1 

K ( k ) = P( 

k −1) 

ϕ j ( k )[ λI 

+ ϕ j ( k ) P( 

k −1) 

ϕ j ( k )] 

(4) 

And 

T 

P ( k ) = [ I − K ( k ) ϕ j ( k )] P ( k − 1) 

/ λ 

(5) 

And, λ is the forgetting factor and I is an i × i identity matrix. Let J k be the Jacobian matrix 

of (1) which is updated at each iteration by adaptive calculation of the system parameters. It is shown 

that the QR-factorization of the matrix product J m J m− 

1...J1 

gives the Lyapunov exponents of the plant 

in equation (1). This process is started with Q 0 = I , and is as follows: 

qr[ 

J J ... J ] = qr[ 

J J ... J ( J Q )] = 

qr[ 

J 

qr[ 

J 

qr[ 

J 

m 

m 

m 

m 

J 

J 

J 

m−1 

m−1 

m−1 

m−1 

... J 

...( J Q )][ R R ] = ... 

... J 

1 

3 

i 

( J Q )][ R ] = 

3 

Q 

2 

2 

i−1 

1 

][ R 

m 

2 

i−1 

R 

m−1 

1 

1 

i− 

2 

... R 

2 

2 

R 

1 

1 

0 

] = ... 

Qm 

[ Rm 

... R2 

R1] 

= Qm 

R 

(6) 

Where, qr[.] denotes the QR-factorization process. Starting with J 1 , at each step, a pre- 

B J Q followed by a QR-factorization of = J Q − = Q R i = 1, 

2,..., 

m is 

multiplication i = i i−1 

performed. Matrix R is the product of the matrices ... R2R1 

Bi i i 1 i i, 

Rm obtained in this sequential manner. 

Furthermore, each of the diagonal elements of R is simply the product of the corresponding diagonal 

elements of all the 

, 

s . Hence, approximation to the n Lyapunov exponents are provided as: 

R i 

m 1 

λ j = lim ∑ ln Ri 

( j, 

j) 

j = 1, 

2,..., 

n 

m→∞ 

m i= 

1 

(7) 

Since the Jacobian matrix of (1) is updated at each iteration, the Lyapunov exponents of the 

system are calculated adaptively at each iteration.

328 Amin Yazdanpanah Goharrizi and Mehdi Semin 

3. Design Methodology 

l 

Let the controlled dynamical system (1), with the input sequence u( k) 

∈ R , be as follows: 

x ( k + 1) 

= f [ x( 

k)] 

+ u( 

k) 

(8) 

For this system finding a feedback control law u ( k) 

= g[ 

x( 

k)] 

, where g: R R 

n → is an 

appropriate function such that the resulting closed loop system exhibits appropriate behavior, is 

desired. So, consider the linear desired model is as follows: 

x ( k + 1) 

= Ax( 

k) 

(9) 

n 

n× 

n 

Where x ∈ R , A∈ 

R is a constant matrix and k = 0, 

1, 

2,... 

is the discrete time index. So, the 

controlled system orbit can behave like the system model "(9)," depends on how the eigenvalues of the 

matrix A is chosen. If the eigenvalues lie in the unit disc then the control action is like a regulation 

problem but if the eigenvalues are on the unit disc the behavior of the closed loop system becomes 

periodic. So, it's sufficient to choose the appropriate control input as follows: 

u ( k) 

= − f [ x( 

k)] 

+ Ax( 

k) 

Then, the methodology is as follows: 

(10) 

⎧0 

u( 

k) 

= ⎨ 

⎩− 

f [ x( 

k)] 

+ Ax( 

k) 

if λmax 

< 0 

if λmax 

> 0 

(11) 

The control action can be applied by adaptive calculation of Lyapunov exponents of the system, 

as discussed in the pervious section. 

4. Nonlinear Observer Design Methodology 

Consider the controlled nonlinear chaotic system as follows: 

x( 

k + 1) 

= f [ x( 

k), 

u( 

k)] 

y( 

k) 

= h[ 

x( 

k)] 

(12) 

n 

where f : ℜ 

p ≤ n . 

n 

n 

→ ℜ , and h : ℜ 

p 

→ ℜ are assumed to be differentiable and smooth functions and 

An observer is a dynamic system driven by the observations which is shown in figure (1): 

xˆ ( k + 1) 

= f [ xˆ 

( k), 

u( 

k)] 

+ L( 

k)[ 

h( 

x) 

− h( 

xˆ 

)] 

In the case of state estimation, we have 

(13) 

lim[ xˆ 

( k) 

− x( 

k)] 

→ 0 

k →∞ 

An approach to the observer design for system (12) is: 

(14) 

J ( x( 

k + 1), 

xˆ 

( k + 1)) 

≤ ∆ when k > k ∗ 

(15) 

With some nonnegative function J , and threshold value ∆ > 0 .


Figure 1: The Nonlinear observer. 

Substituting x ( k + 1) 

and x ˆ ( k + 1) 

from (12) and (13) into (15), and using the gradient method 

for computing the gain of observer we have: 

L( k + 1) 

= L( 

k) 

− α∇ 

( ( 1), 

ˆ 

L( 

k ) J x k + x( 

k + 1)) 

(16) 

Where, α > 0 . Algorithm (16) makes the current observer gain correction 

∆ L( k) 

= L( 

k + 1) 

− L( 

k) 

in the descent direction of the current goal function J . 

5. Simulation Results 

+ 

u 

k 

+ 

+ 

Chaotic 

Plant 

Z -1 

xˆ k + 1 

k 

fˆ 

( ⋅) 

Consider the Henon map as: 

2 

xk 

+ 1 = yk 

+ 1− 

axk 

yk 

+ 1 = bxk 

(17) 

which behaves chaotically when a=1.4 and b=0.3 and periodically when a=1 and b=0.1. Figure 2 

shows the Henon behavior when the parameters change occurs at 1500 from periodically to chaotically. 

h (⋅) 

Figure 2: Henon output whit parameters change at k=1500. 

Lk 

xˆ 

y 

k 

yˆ 

k 

+ 

−


By employing the on-line Lyapunov exponents calculation strategy presented in section 2, 

figure 3 shows the simulation results for the given parameters variations. 

Figure 3: Henon Lyapunov exponents. 

Now, at each iteration the Lyapunov exponents are calculated with the RLS algorithm. Hence, 

if the maximum Lyapunov exponent becomes positive controller is applied to the system as discussed 

in pervious section. First the eigenvalues of matrix A is chosen as 1 , 2 1 = λ on the unit disk, so the 

output (state x) becomes periodic. The result is shown in figure 4. 

Figure 4: The closed loop response. 

The other simulation is performed as a regulation problem which the eigenvalues of matrix A is 

chosen as 1 , 2 0. 

5 = λ . The output of the Henon map (state x) is shown in figure 5 and figure 6 shows 

the estimation error for nonlinear observer.


Figure 5: The closed loop response as a regulation problem. 

Figure 6: estimation error. 

6. Conclusions 

In this paper, an adaptive control of chaos via Lyapunov exponents is presented. A model-based 

approach to adaptive control of chaos in chaotic discrete time systems is presented. A generalized RLS 

algorithm for adaptive estimation of Lyapunov exponents in the case of abrupt parameters change is 

employed. Also, when the sates of the plant are not accessible a nonlinear observer design 

methodology is proposed. Finally, simulation results are provided to show the effectiveness of the 

proposed methodology. 


This work was supported by the complex systems research center in K. N. Toosi University of 

Technology.


References 

[1] G. Chen and J.L. Moiola, "An overview of bifurcation, chaos, and nonlinear dynamics in 

nonlinear system", J. Franklin Inst., 331B, pp. 819-858, 1994. 

[2] M. J. Ogorzalek, "Taming chaos, Part two: Control", IEEE Trans. Circuits Syst. I, vol. 40, pp. 

700-706, 1993. 

[3] G. Chen and X. Done, "From Chaos to Order: Methodologies, Perspectives and Applications", 

World Scientific, Singapore, 1998. 

[4] E. Ott, C. Grebogi and J. A. York, "Controlling chaos ", Phys. Rev. Lett., vol. 64, pp. 1196- 

1199, 1990. 

[5] A.L. Fradkov and A.Y. Pogromsky, "Introduction to control of oscillations and chaos", World 

Scientific, Singapore, 1998. 

[6] D. Lai, and G. Chen, "Computing the distribution of Lyapunov exponent from time series: The 

one-dimensional case study", Int. J. Bifurcation and Chaos, pp. 1721-1726, 1995. 

[7] G. Benettin, L. Galgani, A. Giorgilli and J. M. Strelcyn, "Lyapunov characteristic exponents for 

smooth dynamical systems and for Hamiltonian system: A method for computing all of them", 

Part I & II, Meccanica 15: 9-30, 1980. 

[8] O. Morgul, " Model based anticontrol of discrete time systems". IEEE conference on Decision 

and Control, Maui, Hawaii USA, December 2003. 

[9] A. Yazdanpanah and A. Khaki-Sedigh, "Adaptive Control of Chaos in Nonlinear Discrete-Time 

Systems Using Time-Delayed Sate Feedback," accepted for publication in IEEE Conference of 

Physics and Control, St. Petersburg, Russia, 2005. 

[10] A. Khaki-Sedigh, M. Ataei, B. Lohmann, and C. Lucas,"Adaptive calculation of Lyapunov 

exponents from time series observastion of chaotic time varying dynamical systems", Int. 

Journal of Nonlinear Phenomena, vol. 6, No. 4, pp. 842-851, 2003. 

[11] A. Yazdanpanah and A. Khaki-Sedigh, "Adaptive Control of Chaos in Nonlinear Chaotic 

Discrete-Time Systems," accepted for publication in IEEE Conference of Physics and Control, 

St. Petersburg, Russia, 2005. 

[12] F. Hubertus, E. U. Firdaus, P. Wlodek, "An efficient QR based method for the computation of 

Lyapunov exponents", Elsevier Science, pp. 1-16, 1997. 

[13] Astrom, J. K., & Wittenmark, B., "Adaptive Control, Addision-Wesley", Second edition Sin, 

1995.


ISSN 1450-216X Vol.14 No.3 (2006), pp. 333-338 



Investigation of Complex Formation PDTC with Ni(II) in 

Physiological Conditions 

S. J. Fatemi 

Department of Chemistry 

Shahid Bahonar University of Kerman, Iran 

A. Badiei 

School of chemistry, University College of Science 

University of Tehran, Iran 

E-mail: abadiei@khayam.ut.ac.ir 

A. Hooshmand 

Department of Chemistry 

Shahid Bahonar University of Kerman, Iran 

Abstract 

Complex formation of nickel(II) ion with PDTC, which contains thio donor atoms, 

was investigated using UV-vis spectroscopy. PDTC can be an oral chelator with pKa= 

3.300±0.002. It behaves as a bidentate ligand at serum pH. The effect of pH on Ni 2+ -PDTC 

indicated that the maximum adsorption was at pH=7.4. The effective Ni-PDTC binding 

constant was determined (logk=11.1±0.1) for the 1:2 Ni(PDTC)2 complex using UV-vis 

spectra. 

Keyword: pyrrolidine dithiocarbamate, PDTC, Job's methods. 

Introduction 

The uses for dithiocarbamates are many, from insecticides and fungicides [1] to therapeutic agents for 

alcoholism and metal intoxication [2]. Their applications to treat acquired immune depressive 

syndrome and cancer have also been proposed [3]. Dithiocarbamates have also been used 

experimentally for redox-related cell death [4]. Their mechanism of action is mainly as that of an 

antioxidant with the additional affects of a metal chelator [4] and superoxide dismutase inhibitor [5]. 

Pyrrolidine dithiocarbamate (PDTC) is stable pyrrolidine derivative of dithiocarbamates. PDTC 

contains two thiol moieties and is thus generally recognized as an antioxidant [6]. However, 

Pyrrolidine dithiocarbamate (PDTC) is a metal-chelating compound that exerts prooxidant or 

antioxidant effects and is widely used to study redox regulation of cell function [7]. Nickel has adverse 

biological effects that have cast uncertainty on its safety for use in the body [8]. Nickel ions are also 

toxic in vitro and invivo, [9,10] and can be extremely toxic in some forms such as nickel carbonyl. 

Furthermore, some forms of nickel, such as nickel sulfide, are documented carcinogens, although the 

mechanism of this carcinogenicity is thought to relate ultimately to the release of nickel ions 

intracellularly [9-12].

Investigation of Complex Formation PDTC with Ni(II) in Physiological Conditions 334 

In this work, complex formation of nickel (II) ion with PDTC was investigated by job's method 

using UV-vis spectroscopy at serum pH. 

Experimental 

Reagents: Pyrrolidine dithiocarbamate (PDTC) was purchased from Sigma and NiCl2.6H2O purchased 

from Merck. Other chemicals were obtained from Sigma. 

Method: Stock solution of Ni(II), was prepared by dissolving this chloride in twice-distilled water. 

Electronic absorption spectra of the free ligand and its complex in 0.1M (hepes) containing 5mM 

sodium bicarbonate were recorded using Cintra5 double-beam UV-Vis spectrophotometer. The 

composition of the complex in solution was determined by continuous variation methods [13,14]. All 

chemicals used were of without purification. The pH-metric titrations solutions of the free ligand and 

its mixtures with metal ion was carried out as described earlier [15] using a digital Metrohm pH-meter 

713 with a conventional pH-electrode. Using equations of Irving and Rossotti [16] the curves were 

used to calculate the formation constants of the following equilibria 

And 

M 2+ +HL ML + + H + 

ML + +HL K2 � ML2 + H + 


Determination of pKa for PDTC ligand 

The free PDTC titration was used to calculate ligand pka value of 3.300 with a very good fit σpH= 

0.002 (fig. 1). This value corresponds to the protonation of the thio groups. However, there is chemical 

evidence that suggests, PDTC is more stable at pH 7.4 and it can be expected for oral chelator (bidentat 

ligand) [6].

335 S. J. Fatemi, A. Badiei and A. Hooshmand 

Figure 1: Absorbance of PDTC at various pH for determination of pka. 

Effect of pH on Ni 2+ -PDTC binding 

The effect of pH was studied by using 0.1 N HCl and 0.1 N NaOH. It was observed that the complex is 

stable and absorbance was constant and maximum in the pH range 7.0-9.0 (fig. 2). Here hepes buffer 

of pH 7.4 was selected for maintaining pH constant during the further studies. 

Figrue 2: Effect of pH on Ni 2+ -PDTC binding,25°C [PDTC] ~ 10 -6 M. 

Absorbance 

0.16 

0.12 

0.08 

0.04 

Binding of Ni 2+ to PDTC 

0 

0 1 2 3 4 5 

pH 

6 7 8 9 10 

The electronic absorption spectra of PDTC in hepes buffer solution within the region 200-600 nm 

display two absorption bands (Fig. 3) (λmax, 250 nm and 276 nm). The first band is due to an enhanced 

π�π * transition (K band) [17], while the second band could be attributed to an enhanced n�π * 

transition (R band) [18-21].


The absorbance maxima at 324 nm reflect nickel binding at the two binding sites of PDTC. The 

spectrum reflects that the maximum absorbance at about 324 nm increased rapidly, until the mol ratio 1 

: 2 metal/ligand reached. 

Figure 3: Spectrum of PDTC at 10 -6 M. 

In titrations of PDTC with Ni 2+ alone, there was an isosbestic point at 296 nm (fig.4). The 

binding constant of metal to ligand was determined by using the continuous variation method (Job's 

method) at 324 nm (the obtained maximum absorbance from fig.4). The corrected absorbance was 

plotted against the volume of fraction of PDTC, that is, VM/(VM + VL), where VM and VL are the 

volumes of Ni 2+ and PDTC solutions, respectively (Fig. 5). The maximum values of VM/(VM + VL) = 

0.33 and VL/(VM + VL) = 0.66 obtained from figure 5, thus VL/VM is 2, which suggested that the 

complex had the formula Ni(PDTC)2. It is clear that nickel is binding to both specific metal-binding 

sites of PDTC. The binding of Ni to PDTC can be quite fast. If the nickel is added as a NiCl2, then the 

binding takes many seconds to reach completion. The effective Ni-PDTC binding constant is 

logk=11.1±0.1, this is clearly higher than effective Ni-Tf binding constants (logk1=4.1±0.15, 

logk2=3.23±0.31) [22].

337 S. J. Fatemi, A. Badiei and A. Hooshmand 

Figure 4: A series of difference spectra for Ni 2+ binding to PDTC in 10mM hepes buffer, 5mM sodium 

bicarbonate, pH 7.4, and 25°C [PDTC] ~ 10 -6 M. 

Figure 5: Plot of corrected absorbance against VM/(VM + VL) for determination of molar ratio of Ni 2+ to PDTC. 

[PDTC] = 10 -5 M, [Ni 2+ ] = 10 -5 M, pH 7.4, and 25°C. 

Conclusion 

Complex formation of nickel(II) ion with PDTC, was studied using UV-vis spectroscopy. PDTC can 

be an oral chelator with pKa= 3.300±0.002. It behaves as a bidentate ligand at serum pH. The effect of 

pH on Ni 2+ -PDTC indicated that the maximum adsorption was at pH=7.4. The effective Ni-PDTC 

binding constant was determined (logk=11.1±0.1) for the 1:2 Ni(PDTC)2 complex by job's method 

using UV-vis spectra.


References 

[1] Hays W. J pesticides studied in Man, Williams& Wilkins, Baltimore. pp.436. (1982). 

[2] Thorn g. D. and Ludwig R. A. . Elsevier, Amsterdam. (1962). 

[3] Reisinger E.C. Kern P. Ernst M.,Bock P., Flad H. D., and Dietrich M. Lancent 335,679(1990). 

[4] Orrenius S,. Nobel c. S. I., van den Dobbelsteen d. J.,Burkitt M. J., and Slater A. F. G. 

Biochem. Soc. Trans. 24, 1032. (1996). 

[5] Mirsa H. P. J. Boil. Chem. 254,11623(1979). 

[6] Topping R.J. and jones M. M. Med. Hypothesis, 27,55(1988). 

[7] Nobel CI, Kimland M, Lind B, Orrenius S, Slater AF. J Biol Chem. 270:26202(1995). 

[8] Sunderman FW, editor. IARC;53:3.(1984). 

[9] Sunderman FW, Hopfer SM, Lin SM, Plowman MC, Stojanovic T, Wong SH, Zaharia O, 

Ziebka L. Toxicol Appl Pharmacol;100:107(1989). 

[10] Coogan TP, Latta DM, Snow ET, Costa M. CRC Crit Rev Toxicol; 19:341(1989). 

[11] Costa M. Annu Rev Pharmacol Toxicol;31:321(1991). 

[12] Sunderman FW. Arch Toxicol Suppl;13:40(1989). 

[13] Yoe, J. H. and Jones, A. L., Ind. Eng. Chem., Anal. Ed. 16, 111 (1944). 

[14] Job, P., Ann. Chim. 9, 113 (1928); 11, 97 (1936). 

[15] Taha, A., El-Shetary, B., and Linert, W., Monatsh. Chem. 124, 135 (1993). 

[16] Irving, H. M. and Rossotti, H. S., J. Chem. Soc., 2904(1954). 

[17] Silveration, R. M., Bassler, G. C., and Morrill, T. C.. Wiley, New York, 1981. 

[18] Ramadan, A. A. T., El-Behairy, M. A., Ismail, A. I., and Mahmoud, M., Monatsh. Chem. 125, 

1171 (1994). 

[19] Ramadan, A. A. T., Abdel-Rahman, R. M., and Seda, M. H., Asian J. Chem. 4, 569 (1992). 

[20] Ramadan, A. A. T., Abdel-Rahman, R.M., El-Behairy, M. A., Ismail, A. I., and Mahmoud, M., 

Thermochim. Acta 222, 291 (1992). 

[21] Taha, A., El-Shetary, B., and Linert, W., Monatsh. Chem. 124, 135 (1993). 

[22] Harris WR, . J. Inorg. Biochem.; 27; 41(1986).


ISSN 1450-216X Vol.14 No.3 (2006), pp. 339-345 



Germination Studies in Selected Native Desert Plants of Kuwait 

Sameeha Zaman 

Aridland Agriculture and Greenery Department 

Kuwait Institute for Scientific Research 

P. O. Box 24885 Safat, 13109, Kuwait 

Email: szaman@safat.kisr.edu.kw 

Tel: (00965) 4836100, Fax: (00965) 4815194 

Shyamala Padmesh 



P.O. Box 24885 Safat, 13109, Kuwait. 

Tel: (00965) 4836100, Fax: (00965) 4815194 

Narayan R. Bhat 




E-mail: nbhat@safat.kisr.edu.kw 

Tel: (00965) 4836100, Fax: (00965) 4815194 

Harby Tawfiq 




Tel: (00965) 4836100, Fax: (00965) 4815194 

Abstract 

Revegetation and population enhancement of species are key elements of native 

species conservation. Dormancy is a well recognized survival adaptation in desert plant 

seeds to escape uncertainties of nature and hence, efficient seed dormancy breaking 

techniques are necessary for rapid enhancement in population in these species. Because 

efficient techniques for mass propagation of native plants are not presently available, largescale 

revegetation projects have not been very successful in Kuwait. Therefore, 

germination studies were undertaken in five native desert species (Cyperus conglomeratus, 

Citrullus colocynthis, Moltkiopsis ciliata, Astragalus siebierri and Phragmites australis). 

Seeds were subjected to various treatments: high temperature (50ºC) stratification, 

scarification, soaking in gibberellic acid or potassium nitrate solutions prior to sowing. 

Germination in Cyperus conglomeratus and Moltkiopsis ciliata was promoted by high 

temperature stratification. In Cyperus conglomerates, high temperature stratification for 60 

to 90 days increased the germination by 51 – 83 %; however, the effects of high 

temperature stratification on germination of Moltkiopsis ciliate in absolute terms were 

evident only when seeds were stratified for at least 120 days. In Cyperus conglomeratus

Germination Studies in Selected Native Desert Plants of Kuwait 340 

and Phragmites australis, soaking of seeds in GA3 solution for 24 hrs increased the 

germination from germination by 64 and 86%, respectively. While hot water treatment 

improved the germination in Asteragalus sieberri seeds, KNO3 was more effective than 

heat treatment in increasing the germination of Citrullus colocynthis seeds. 

Key words: Revegetation, propagation, biodiversity conservation, gibberellic acid, 

stratification, seed dormancy 


Extreme aridity of the climate, over grazing, Gulf war activities and other human activities have led to 

a significant loss of native vegetation cover, increased mobility of sand particles and the frequent 

occurrences of dust storms in the Kuwaiti desert. Encroachment of agricultural lands, roads and other 

infrastructure by wind blown sand has also become a serious problem in Kuwait (Abdulwahid, 1979; 

Abolkhaire, 1981). Because the majority of native plants in Kuwait are annuals, uncertainties of 

climate have a major influence on their germination, establishment, flowering and seed production. 

The lack of sufficient native seed stocks has been the main bottleneck in all restoration programs in the 

region including Kuwait (Peacock et al. 2003). Under normal conditions, seeds get buried in soil and 

remain dormant for several years until sufficient amount of rainfall percolate into the soil to initiate 

germination and new growth. 

In nature, germination of fresh seeds in desert species is usually prevented by adverse climatic 

conditions (drought and extreme temperatures). Hard seed coats and presence of high levels of growth 

inhibitors also allow them to remain dormant during unfavorable growing conditions. Dormancy is 

normally broken when seeds after they have absorbed sufficient moisture are exposed to mild 

temperatures. The availability of sufficient moisture in the soil is also necessary to leach out growth 

inhibitors present in the seed completely, a precondition to be fulfilled for successful germination 

(Bryant, 1985). 

Efficient propagation and establishment techniques that are crucial for both conservation of 

native species and large-scale revegetation programs are currently not available. In view of these facts, 

studies were conducted to determine the effects of seed treatments on germination in five main native 

desert species (Cyperus conglomeratus, Citrullus colocynthis, Moltkiopsis ciliata, Astragalus sieberri 

and Phragmits australis). 

2. Materials and Methods 

2.1. Climate and Soil of Kuwait 

Geographically, Kuwait occupies approximately 17,800 km 2 of the northwestern part of the Arabian 

Gulf, between 28º30’ and 30º05’N, and 46º33’ and 48º30’E It is bounded on the South by Saudi 

Arabia, on the North and west by Iraq, and on the East by the Arabian Gulf.(Annual Statistical 

Abstract, 1998). Kuwait’s climate is characterized by harsh summers and mild winters. Temperature 

extremes are high, with means during the warmest and coolest months ranging between 46.2ºC and 

6.9ºC (Annual Statistical Abstract, 1998). Winter brings occasional frost. Rainfall is minimal, not 

exceeding 115 mmyr -1 , but evaporation is very high, averaging 14.1 mm.d -1 . The relative humidity is 

low, and strong, dry and hot, northwesterly winds prevail during summer, particularly in June and July. 

Kuwait’s soils are sandy in texture, alkaline, high in calcareous materials (CaCO3) and low in organic 

matter and plant nutrients. Underground water resources are limited and brackish in nature with total 

dissolved solids (TDS) concentrations ranging from 3.0 to 10.0 g.L -1 .

341 Sameeha Zaman, Shyamala Padmesh, Narayan R. Bhat and Harby Tawfiq 

2.2. Seed Collection 

Seeds of Moltkiopsis ciliata, Citrullus colocynthis were collected during 2004 from Agriculture 

Research Station in Sulaibiya. Seeds of the remaining three species, Astragalus siebierri, Cyperus 

conglomeratus and Phragmites australis were collected from Shegayah, Saban and Doha areas, 

respectively. Seeds were stored in dry paper bags at room temperature until they were cleaned and only 

the seeds that contained healthy and filled embryo were selected for the study. 

2.3. Germination Studies 

Separate experiments were performed in each of the five species at the Seed Laboratory of Kuwait 

Institute for Scientific Research. These tests were conducted in 9-cm diameter disposable petri dishes 

lined with a moist filter paper. A seed was considered germinated when the radicle protruded to a 

length of at least 2 mm. The seed treatment differed with species as follows: 

2.3.1. Cyperus conglomeratus 

Healthy seeds were placed in glass beakers and maintained in an oven at 50ºC for 0, 1, 2, 3, or 12 

months as per the procedure recommended by Brown and Al-Mazrooei (2001). Following the high 

temperature treatment, seeds were sown in petri dishes and placed in continuous darkness in a growth 

chamber at 30ºC. Another batch of seeds was soaked in 0, 100, 200, 300, 500 or 1000 ppm GA3 

solution for 24 hrs prior to sowing. After soaking, seeds were sown in petri dishes and maintained in 

the growth chamber at 30ºC with continuous darkness. The number of germinated seeds was counted 

each day. 

2.3.2. Citrullus colocynthis 

Seeds of this species were stratified at high temperature (50ºC) for 0, 30, 60, 90, 120, 180 or 270 days. 

Another batch of seeds was treated overnight with 0.3% KNO3 solution. Same procedures as described 

above were used for high temperature stratification and chemical treatment. Sets of 25 seeds each were 

placed on a moist filter paper in 9cm diameter disposable petri dishes and maintained in the growth 

chamber. The number of seeds that germinated was counted each day up to 10 days. 

2.3.3. Moltkiopsis ciliata 

Seeds were stratified at 50ºC for 0, 1, 2, 3, or 12 months. Four replicates of 25 seeds each were sown in 

9cm petri dishes and were maintained at room temperature. The number of seeds that germinated was 

counted each day. 

2.3.4. Astragalus sieberri. 

Seeds were placed in boiling water until all the seeds were swollen. After the treatment, four replicates 

of 25 seeds each were sown in 9 cm petri dishes and maintained at room temperature. The number of 

germinated seeds was recorded each day. Another batch of seeds was stratified at 50ºc for varying 

number of days. The germination of stratified seeds was determined at room temperature. 

2.3.5. Phragmitis australis. 

The treatments included soaking of seeds in 500, 1000 or 2000 ppm GA3 solution for 24 hrs. After 

soaking, four replicates of 25 seeds were sown in petri dishes, which were then placed in a growth 

chamber at 30ºc with continuous darkness for recording the germination percentage in each treatment. 

2.4. Statistical Analysis. 

The data was subjected to the one way analysis of variance (ANOVA) at 5% level of confidence. The 

data from boiling water treatment in Astragalus sieberri and KNO3 treatments in Citrullus colocynthis


were analyzed using the Student “t” test at 5% level of confidence. Mean separation was performed 

using the Duncan’s Multiple Range Test (Little and hill, 1978). 

3. Results 

3.1. Cyperus conglomeratus 

Seed germination in this species was promoted by both high temperature stratification and GA3 

treatments (Table.1). The highest germination was achieved when seeds were maintained at 50ºC for 

60 days. Extending the heat treatment beyond 60 days adversely affected germination. Similarly, 

soaking seeds in 1000 ppm GA3 solution increased the germination from 10% in control to 74%. 

Table-1: Effect of High Temperature Stratification and GA3 Treatment of Seeds on Germination in Cyperus 

conglomeratus 

Treatments* Final Germination (%) 

Seed stratification at 50ºC (Days) 

Control 3 a** 

60 86 c 

90 80 bc 

150 54 b 

210 72 bc 

240 54 b 

300 66 bc 

S.E 12.52 

Gibberellic acid (ppm) 

Control 10 a 

100 38 b 

200 43 b 

300 47 b 

500 53 b 

1000 74 c 

S.E 9.28 

* Stratification and GA3 treatment effects were tested separately in two experiments. 

** The treatment means followed by the same letter within each experiment are not statistically different at P


Table-2: Effects of KNO3 and High temperature stratification on germination of Citrullus colocynthis 

Treatmentsx Final Germination (%) 

Control 3 a 

Soaking in 0.3% KNO3* 70 b 

Seed stratification at 50ºC** 

Control 2 a 

30 days 0 a 

120 days 44 b 

240 days 36 b 

280 days 0 a 

370 days 1 a 

S.E. 8.28 

x Stratification and KNO3 treatment effects were tested separately in two experiments. 

* Seeds soaked in 0.3% KNO solution for 24 hrs were used for sowing. Treatment value is significant at P


Table-4: Effects of Boiling water & High temperature Stratification on germination of Astragalus sieberri 

Treatmentsx Final Germination (%) 

Control 3 a* 

Soaking seeds in boiling water 60 b 

Seed stratification at 50ºC for ** 

Control 2 a 

20 days 1 a 

30 days 4 a 

50 days 4 a 

75 days 5 a 

100 days 6 a 

130 days 2 a 

S.E 2.92 

x Stratification and Boiling water treatment effects were tested separately in two experiments. 

* The treatment values followed by the same letter are not statistically different at P



The authors would like thank the Kuwait Foundation for the Advancement of Sciences and Kuwait 

Institute for Scientific Research for supporting this research. The assistance provided by the project 

staff in executing the study is gratefully acknowledged. 

References 

[1] Abolkhair, Y. A. S., 1981. Sand encroachment by wind in Al-Hassa of Saudi Arabia, Ph.D. 

Dissertation. Department of Geography. Indiana University, Bloomington, IN, USA. 

[2] Agboola DA and M. O. Adedire 1998. Response of treated dormant seeds of three species to 

germination promoters. Nigerian Journal of Botany 11: 103-109. 

[3] Annual Statistical Abstract (1998): Ministry of Planning. Statistical and Information Sector. 

Edition 35. Kuwait. 

[4] Bradbeer J. W. 1988. Seed dormancy and germination. Blackie and Son, Glasgow and London 

UK. 

[5] Brown, G and S. Al-Mazrooei,. 2001. Germination ecology of Haloxylon salicornicum from 

Kuwait. Botanische. Jahrbiicherfiir Systematik, pflanzengeschichte und pflanzengeographie 

123:235-247. 

[6] Bryant, J. A.1985. Seed physiology. Edward Arnold, Baltimore, USA. 76pp. 

[7] Ergenoglu, F., S. Tangolar, S. Gok and A.B.Kuden, 1997. The effects of some pretreatments for 

promoting germination of dormant grape seeds. Acta Horticulturae, 441:201-212. 

[8] Lippitt, LX.1992. X-ray analysis seed forum Red Rock Canyon State Park, Notes for 

SDSU/CDP and R 8/92. 

[9] Little, T. M., and F. J. Hills. 1978. Agricultural Experimentation. John Wiley and Sons, New 

York, USA 350 pp. 

[10] Peacock, J.M., M.E. Ferguson, G.A.Alhadrami, I.R.Mc Cann, A. Al Hajoj, A . Saleh and R. 

Karnik. 2003. Conservation through Utilization: A case study of the indigenous forage grasses 

of the Arabian Peninsula. Journal of Arid Environments 54:15-28


ISSN 1450-216X Vol.14 No.3 (2006), pp. 346-353 



Age at Menarche, Current Premenstrual Syndrome and Health 

Risk Behaviour of Young People in Ibadan, Nigeria 

Moronkola, O.A 

Senior Lecturer (Health Education)Health Education Unit 

Dept. of Human Kinetics and Health Education 

University of Ibadan, Ibadan. Nigeria 

Email: walemoronkola@yahoo.com 

Aladesanyi, O.A 

Health Education Unit 

Dept. of Human Kinetics and Health Education 

University of Ibadan, Ibadan. Nigeria 

Abstract 

Objective: To determine age at menarche, current premenstrual syndrome and at risk 

behaviour of female students in a tertiary institution in Ibadan, Nigeria. 

Design: Cross-sectional study 

Setting: A tertiary institution in Ibadan, Nigeria. (The actual name of the institution is 

concealed based on agreement with the study participants) 

Participants: 500 female students of a tertiary institution in Ibadan, Nigeria 

Materials and Methods: Female students of a tertiary institution in Ibadan, Nigeria were 

randomly sampled for the study. Structured questionnaires were administered to them in 

order to obtain information on their age at menarche, current premenstrual syndrome and 

health risk behaviour. 

Result: Out of the 500 participants, majority 365 (73.0%) had menarche between 11-15 

years over 60.0% of them experienced the following symptoms of premenstrual syndrome; 

irritable/touchy 91.8%, not wanting to eat 87.6%, sleep disturbances 87.4%, anxiety 

85.2%, lowered self esteem 80.6%, fatigue 78.2%, feeling weak 73.6%, water retention 

72.0%, fainting 71.4%, desire to eat food 68.6%, dizziness 66.4%, breast tenderness 

62.8%. Also 88.8% had procured abortion before, 86.8% did enjoy high salt intake, 77.4% 

were drinking alcohol, 73.8% engaged in premarital sex, 68.0% were drinking coffee, 

9.8% did not deliberately engage in exercise/physical activity while 7.4% were not taking 

time to relax. 

Conclusion: The study showed that majority of the female students had menarche within 

the age period consistent with literature and had also procured abortion. Most of them 

complained about several symptoms of premenstrual syndrome. There is therefore, an 

urgent need for health education and promotion activities against premarital sex and 

abortion with attendant consequences as well as how the participants can manage 

symptoms of premenstrual syndrome and the need for sexual health counselling in the 

health services centre in tertiary institutions.


Health Risk Behaviour of Young People in Ibadan, Nigeria 347 

Introduction 

Menstruation is the monthly process in which an unfertilized egg cell and the inner lining of the uterus 

are discharged from a woman of reproductive age. Most girls start to menstruate around the age of 12; 

some may mature earlier or later than this. Menstruation may begin any time between the ages of 10-16 

and still considered normal 1 . 

The first menstrual cycle or periods usually starts between ages of 12 and 15 years and this is 

known as menarche. 2,3 Menstruation is a normal biological process, but it may cause physical or 

psychological problems too. 4 Menstruation has been surrounded by myths, superstitions, rituals and 

even laws since the earliest times. In modern times, it is viewed with remarkable openness, but 

differences in attitude still occur between different population and cultures. 5 Menstrual disorders like 

amenorrhea, dysmennorrhea and premenstrual syndromes are common reasons for visits to healthcare 

providers by adolescent girls. Although menstrual irregularity during the first few years after menarche 

may be normal, other menstrual signs and symptoms may indicate a pathological conditions requiring 

prompt medical attention. 6 

Premenstrual syndrome (PMS) is a feeling of depression that occurs several days to two weeks 

before a period begins. Other symptoms may be weight gain and the inability to sleep or concentrate. 

The main cause of PMS is still unknown. 1 Premenstrual syndrome refers to the recurrent somatic or 

psychic symptoms which may occur in relation to menstruation. 7 About 70 percent of menstruating 

women experience some psychological and physiological changes the week before menstruation. 

Symptoms of PMS may include headaches, depression, undue stress and on rare occasions violent 

behaviour. 3 

The premenstrual syndrome is a complex of symptoms occurring in the latter half of the 

menstrual cycle and disappearing at onset of the menstrual flow. The time of occurrence as well as the 

severity of symptoms and their number do vary considerably. The syndrome was described by Frank in 

1931. 8 

Most women have some premenstrual syndromes due to several environmental factors. 9 

Though in many countries, sex, reproductive health and abortion are shrouded in secrecy even in the 

privacy of homes and with family members, the problem of unwanted pregnancy and unsafe abortion 

continue to endanger the lives and wellbeing of Africa and these are enormous interms of losses and 

suffering to individuals, families and communities. 10 The consequences of unsafe abortion in Africa 

are enormous interms of losses and sufferings to individuals, families and communities, yet, there has 

remained an unmitigated silence at all levels regarding the need to do something to reduce the scale of 

the problem. 11 

Tertiary institution students are predisposed by environmental factors to adoption of habits that 

impact on their health. Smoking, alcohol abuse, a sedentary lifestyle and failure to use health services 

may jeopardize current and future health status. 12 

The purpose of this study therefore was to find out age at menarche, premenstrual syndrome 

and health risk behaviour of students of a tertiary institution in Ibadan, Nigeria. 


One of the oldest institutions of higher learning in Ibadan southwestern Nigeria (noted for its high 

literacy level among other zones of the country) is recently witnessing high scale unwholesome sexual 

escapades of the students, cultism and admission racketeering which on several occasions led to the 

closure of the institution. 

A cross-sectional design was adopted for this study. The study participants were female 

registered students of the institution in 2003/2004 academic session. Trained (female students) research 

assistants were used to randomly administered copies of questionnaire on female students. The copies 

of the questionnaire after administration were manually screened for adequacy of completion and 500

348 Moronkola, O.A and Aladesanyi, O.A 

(82.3%) out of 620 copies administered were found useable for data analysis. The data were analyzed 

using SPSS package. Element of volunteerism on the part of participants was inherent as a major 

determinant to participate in the study was the assurance that participants identities and that of the 

institution will not be disclosed. 

Results 

Out of the 620 female students surveyed, 500 (80.6%) completely filled their questionnaires. The 

general characteristics of the students are summarized in table 1. 

Table 1: Socio-demographic characteristics of female students of a tertiary institution in Ibadan, Nigeria. 

n=500 

Students’ characteristics (%) 

(i) Level of study 

Preliminary studies year 43.0% 

Year 1 39.6% 

Year 2 11.0% 

Year 3 5.8% 

Year 4 0.6% 

(ii) Age (Yrs) 

Below 16 2.6% 

16-20 26.2% 

21-25 39.2% 

26-30 20.8% 

31-35 10.8% 

36-40 0.4% 

In table 1 above out of 500 study participants, preliminary studies year students constituted 

43.0%, year 1,39.6%, year 2, 11.0% year 3, 5.8% and year 4, 0.6%. Also majority of the participants 

were between 21-25 years of age. 

Table 2: Age at Menarche of students of a tertiary institution in Ibadan, Nigeria 

n=500 

Age (Yrs) Menarche % 

≤10 

5.6% 

11-15 73.0% 

16-20 20.8% 

21 and above 0.6%



Table 3: Premenstrual syndrome among female students of a tertiary institution in Ibadan, Nigeria 

n=500 

Premenstrual syndrome Have it (%) Do not have it (%) 

Feeling weak 73.6% 26.4% 

Fainting 71.4% 28.6% 

Irritable/Touchy 91.8% 08.2% 

Pain 84.4% 15.6% 

Breast tenderness 62.8% 37.2% 

Desire to eat food 68.6% 31.4% 

Water retention (stomach/feet/hand) 73.8% 28.0% 

Anxiety 85.8% 14.2% 

Dizziness 66.4% 33.6% 

Headache 84.6% 15.4% 

Fatigue 78.2% 21.8% 

Physical Discomfort 83.4% 16.6% 

Lowered self-esteem 80.6% 19.4% 

Sleep disturbances 87.4% 12.6% 

Sensitivity to light 82.2% 17.8% 

Not wanting to eat 87.6% 12.4% 

Table 4: Health risk behaviour of female students of a tertiary institution in Ibadan, Nigeria within the last one 

year 

n=500 

At risk behaviour Yes (%) No (%) 

High salt intake 86.8 13.2 

*Deliberate engagement in exercise/physical activity 90.2 9.8 

Drink alcohol 77.4 22.6 

*Take time to relax 92.6 7.4 

Drink coffee 68.0 32.0 

Engagement in premarital sex 73.8 26.2 

Procument of abortion 88.8 11.2 

* Positive health behaviour 

Age at Menarche 

Of the 500 study participants in table 2: 5.6% had menarche ≤ 10 years, 73.0% 11-15 years, 20.8% 16- 

20 years and 0.6% 21 years and above. This shows that majority of them had menarche between 11 and 

15 years. 

Premenstrual Syndrome 

Of the 500 study participants in table 3: more than 50.0% experienced one form of symptom of 

premenstrual syndrome or the other in this descending order; irritable/touchy 91.8%, not wanting to eat 

87.6%, sleep disturbances 87.4%, anxiety 85.8%, headache 84.6%, pain 84.4%, physical discomfort 

83.4%, sensitivity to light 82.2%, lowered self esteem 80.6%, fatigue 78.2%, feeling weak 73.6%, 

water retention 72.0%, fainting 71.4%, desire to eat food 68.6%, dizziness 66.4% and breast tenderness 

62.8%. 

Health Risk Behaviour 

Out of the 500 study participants in table 4: 88.8% had procured abortion, 86.8% did enjoyed high salt 

intake, 77.4% were drinking alcohol, 73.8% engaged in premarital sex, 68.0% were drinking coffee, 

9.8% did not deliberately engage in exercise/physical activity while 7.4% did not take time to relax.


Discussion 

The overall response rate of 80.6% was considered good for this study. The use of female research 

assistants (fellow students) made it possible to attain the responses got in this study. 

Majority of study participants 73.0% recalled that they had menarche between 11-15 years 

which is consistent with literature. 

13, 14, 15 

More than 50.0% of the study participants experienced one form of symptom premenstrual 

syndrome or the other. Among Afrikaans speaking university students in USA, premenstrual symptoms 

or sign experienced were irritability 87.0%, depression 87.0%, moodiness 77.0%, anxiousness 31.0%, 

headache 47.0%, breast tenderness 71.0%, fatigue 77.0%. 5 Generally, depressive mood, irritability, 

increase tendency to accidents and criminal behaviour, headache, abdominal pain, nausea and vomiting 

are found in literature as premenstrual syndrome.8 Depending on the methodology used by the 

researchers, it has been shown that between 30.0% and 90.0% of women reported some physical or 

emotional premenstrual symptomalogy. 9 The full range of premenstrual syndrome includes: confusion, 

disorientation, intemperate judgments and decision making, moods swings, body aches, anger and 

verbal abuse, lethargy alternating with increased energy, alienation, guilt (at having abused friends), 

lack of self-esteem, craving for sweet especially chocolate. People experiencing PMS may have 

degrees of severity, from mild to overwhelming. 16 Recent studies shows that as many as 80.0% 

American women have PMS at sometime during the average 400 menstrual cycles occurring between 

menarche and menopause or the time between when the menstrual period start at puberty and when it 

ceases after menopause. 17 

In London, out of 79.0% of women who participated in a study had the responses as 

premenstrual syndrome symptoms experienced thus; irritability 38.0%, swelling 24.0%, 

headache/depression/moods/weight gain 19.0%, fatigue 18.0%, tender breasts 14.0%, pain 13.0% and 

anxiety 11.0%. 18 It is a well known fact that breast symptoms are associated with PMS. 19 

In a study among Nigerian schools, in general, about 10.0%-22.0% of the school girls reported 

severe premenstrual symptoms in all symptom-complex categories the proportion being highest for 

behavioural change 22.0%, arousal 20.6%, physical symptoms 18.7% and concentration 16.7%. 20 

Many social, cultural, economic and individual factors contribute to increase risk and 

vulnerability among young people. Knowledge about habits and practices prevalent among adolescents 

and young adults is important from the public health point of view, since it provides a solid basis for 

structuring preventive strategies, evaluating ongoing interventions and undertaking epidemiologic 

surveillance. 21 A study among university of Ibadan students found 46.1% drinking alcohol, 28.6% 

reported no day exercise per week. 12 Alcohol consumption affect the body in several ways including 

dilation of blood vessels, affect negatively body organs, increases urine production, leads to damage to 

brain tissue, leads to cirrhosis of the liver, increases the amount of sugar in the blood stream as well as 

nutritional deficiencies. 3 

Physical activity is fundamental to daily life, 22 and participation in physical activities/exercises 

improve physical, mental and social health. Nevertheless, many people especially female students who 

are not athletes often times do not engage in physical activities intentionally. The major reason for non 

participation in sports or physical activities by people may be time availability. 23,24 Though tertiary 

education is demanding to students, there is the need to relax against stress. Premarital sex with its 

attendant health consequences are common among young people, especially with the scourge of 

sexually transmitted infections including HIV/AIDS. 25,26,27 Coffee intake often leads to insomnia and 

there is the need for caution against its use. 28,29 

In vast majority of African countries, abortion remains both unauthorized and unsafe. 10 In 

countries where access to safe abortion is restricted, the situation is notably precarious for unmarried 

women especially adolescents who have little or no access to reproductive information and counselling 

and are frequently excluded from contraceptive services. 27 . Limited information available to 

adolescents may indicate that conservative values may not be protecting them from sexual 

experimentation. 30 There is an urgent need for health education intervention programme against health



consequences of premarital sex, abortion as well as how to manage premenstrual syndrome for the 

students through the effort of the school health centre, NGOs focusing on reproductive health in 

Ibadan, Nigeria. A concerted effort must be made by tertiary institutions administrators in Nigeria and 

elsewhere in Africa to initiate or improve on a general course for all students to empower them to be 

able to make healthy decisions related to their current and future health status.


References 

[1] Getchell, B, Pippin R & Varnes, J. Health. Boston: Houghton Mifflin Company 1991. 

[2] Arkutu, A.A. Healthy women, healthy mothers: An information guide new York: Family Care 

International 1995. 

[3] Meeks-Mitchel, L & Heit, P. Health a wellness approach Columbus: A Bell & Howell 

Company 1987 

[4] Insel, P.M, Roth, W.T, Rollins, L. M & Petersen, R.A. Core concepts in health Califonia: 

Mayfield Publishing Company 1998 

[5] Cronje, H.S. & Kritzinger, I.E. Menstruation: Symptoms, management and attitudes in 

University students Int.Gynecol Obstet 1991; 35: 147-150. 

[6] McEvoy, M, Chang, J & Coupey, S. Common menstrual disorders in adolescence. Nursing 

interventions. Am. J. of Mat. Ch. Nur. 2004; 29:1, 41-49. 

[7] Timonen, S. & Procope, B.J. Premenstrual syndrome and physical exercise Acta Obstet Scand. 

1971:331-337. 

[8] Jordheim, O. The premenstrual syndrome Acta. Obstet. and Gynecol. 1972; 51: 77-80. 

[9] Marvan, M.L. & Escobedo, C. Premenstrual symptomatology: Role of prior knowledge about 

premenstrual syndrome Psych. Med. 1999; 61: 163-167. 

[10] Brookman-Amissah, E. Saving African Women’s Lives from unsafe abortion – Everyone has a 

Role to Play Afr. J. Reprod. health 2004; 8, 1: 11-14. 

[11] Okonofua, F.E. Breaking the silence of prevention of unsafe abortion in Africa Afr. J. Reprod. 

Health 2004:8,1:7-8. 

[12] Alagh, T.B. & Omokhodion, F.O. Health related practices of students of the University of 

Ibadan Afr. J. Med. Sc. 2004; 33: 109-114. 

[13] Goyea, H.S. Age at menarche and pre-menarcheal awareness of some Benin City school girls. 

East Afr. Med. Jrn. 1982; 59: 610-615. 

[14] Sogbamu, M.O & Aregbesola, Y.A. Menarcheal age in Nigeria schoolgirls: Its relation to 

height, weight and menstrual profile. Int. Gynecol Obstet. 1979; 16: 39-40. 

[15] Watson, C. & Brazier, E. You, Your life, your dreams: A book for adolescents. 2000; Family 

Care International 

[16] http://www.midlife –passages.com/page 121.html.PMS accessed 6/5/2005 

[17] http://www.tidesoflife.com/pms/htm premenstrual syndrome accessed 6/5/2005 

[18] Scambler, A and Scambler, G (1985) Menstrual symptoms, attitudes and consulting behaviour. 

Soc. Sc. and Med. 1985; 20, 10: 1065-1068. 

[19] Godwin, P.J. Miller, A, Del-Giudice, M.E and Ritchie, K. Breast health and associated 

premenstrual symptoms in women with several cyclic mastopathy. Am. J. Obstet. and Gynecol. 

1997; 176, 3: 998-1005. 

[20] Fakeye, O. & Adegoke, A. (1994). The characteristics of the menstrual cycle in Nigerian school 

girls and the implications for school health programmes Afr. J. Med. Med. Sci. 2001; 23: 13- 

17. 

[21] Merchant-Hamann, E, Ekstrand, M, Hudes, E.S, and Hearst, N. Prevalence and correlates of 

HIV-related risk behaviours among adolescents at public schools in Brasilia AIDS and 

Behaviour. 2002; 6, 3: 283-293. 

[22] Prentice, A.M. & Jebb, S.A. (1995) Obesity in Britain gluttony or sloth? Brit. Med. J. 1995; 

311: 437-439. 

[23] Biddle, S.J. Exercise motivation across life span In S.J. Biddle (Ed). European perspectives on 

exercise, and sport psychology 1995; (pp.3-25) Leeds: Human Kinetics Europe. 

[24] Boothby, J. Ceasing participation in sports activity Jrn. Leis. Res. 1981; 13: 1-14. 

[25] Smith, D.J. Premarital sex, procreation and HIV risk in Nigeria Std. in Fam. Plan. 2004; 35 4: 

223-235.



[26] Moronkola, O.A & Oso, T.E. Sexual behaviours of female undergraduates in a Nigeria 

university: Implications for school health education and services Jrn. Int. Council for Health, 

P.E, Rec, Sp and Dance 2001; 37: 56-59. 

[27] Gilbert, L & Alexander, L. A profile sexual health behaviours among college men Psychol. 

Rep. 1998; 82, 1: 107-116. 

[28] Dusek, D.E. & Girdano, D.A. Drugs: a factual account Yaba: F & A Publishers Ltd. 1989. 

[29] Carrol, C.R. Drugs in modern society Dubuque. Win. C. Broom Publishers. 1989. 

[30] Rob, and Mutahara, M.U. Premarital sex among urban adolescents in Bangladesh Int. Qtly. 

Com. Health Edu. 2001; 20, 1: 103-111.


ISSN 1450-216X Vol.14 No.3 (2006), pp. 354-358 



The Assesment of Participation Decisionmaking of Head Nurses 

to According Training Programs and Supply Medical 

Equipment and Safty of Occupational Health and Alloceation 

Budget and Related between their Individual Variables at the 

Training Hospitals of Iran University of Medical Sciences 2005 

Maryam Nooritajer 

Assistant professor and manager of public health department 

Iran university of medical sciences 

School of Nursing & midwifery, Tehran, Iran 

Rashid-yasami st. Valiasr Ave school of Nursing & 

midwifery manger of Department of community Health Nursing 

Email: Maryam Noorytajer@yahoo.com 

Faezeh Nouroozinjad 

Nursing management at educational of healt 

Iran university of medical science Rashid-yasami street. Valiasr avenue Tehran 

Ezatjafarchla 

Faeulty member , Iran university of medical 

science Rashid-yasami street. Valiasr avenue Tehran 

Fatemeh 

Faculty member school of management Tehran valiasar 

Iran University of medical sciences Iran University of medical science 

Rashid-yasami Street. Valiasr avenue, Tehran 

Hosseini 

Faculty member school of management Tehran valiasar 

Iran University of medical sciences Iran University of medical science 

Rashid-yasami Street. Valiasr avenue, Tehran 

Introduction 

Decision making is the most serious affair management function and the selection of manner and 

decision making style is one of the most of important of skills manager’s at the decision making. 

(Dawer 1996). Whatever the decision making style of manager be suitable with decision position, there 

fore probability it be increase the effective decision adopting attention that decision style of nursing 

managers is one the important factors at the deter main of employees satisfaction. Whatever the 

partnership and cooperation at the adopting decisions will be increase the rate of employer’s 

satisfaction will be increase. 

Grifild (2002) told that Quality of management is dependence of decision making Quality and 

he is claimant that decision making is one the importance manager’s function. Because the results 

Quality that the mangers will be received are dependant decisions that the adopting manages.

The Assesment of Participation Decisionmaking of Head Nurses 355 

The manners of decision making that used at the subjects on the participation decision making 

can be commendation at the four domains. 

1) daily performance employers 

2) work environment 

3) work situation 

4) politic and strategies 

Doglas (1996) said that participation decision making is dealing with forms and procedure of 

leadership also he said that the leaders can done the employers to the different grates at the 

participation decision making. 

The minimum of participation of decision making of them are containing ideas, employer’s 

beliefs before to take end decision making and the maximum of participation are, containing permitted 

to employers for decision making adopting with limitation appointment. 

Tosie 2001 declaration that participation of decision making is a technical method that with this 

matter the organization have possibility that the employers can fond helmet knowledge’s and attitude’s 

at the background efficiency and effectiveness and done it and they can done of strength to action 

Hober 2000. 

Colency 2003 believed the head nurses have the important role at the preservation employers 

satisfaction if they have knowledge about of executive principles of managerial based an employers 

participation and decision making styles could be terminating to increase their satisfaction. 

The effect of participation of decision making have the important role on the form of decision 

making and leading to promotion and Quality improvement at the decisions making, also support 

increasing of decision making participation and the results increasing is at the performance and 

decision making researches. The results of participation leading to ownership and more capitalism at 

the organization situation and increasing effectiveness and Quality 

Therefore the researcher wants to done a survey about participation decision making of head 

nurses also answer to this question that is the individual factors could be effect to this relation ship. 

The goal objective: determine the participation decision making of head nurses to according 

training programs and supply medical equipment and safety of occupational health and special 

hospital’s budget and related between their individual variables at the training hospital of Iran 

university of medical sciences. 

Special objectives 

1. determine the rate of participation decision making of the head nurses in the training hospitals of 

Iran university of medical sciences 

2. determine the rate of participate decision making of head nurses according training programs , 

supply medical equipments and safety and occupational health, allocation budget 

3. the determine corrective participation of decision making the head nurses according individual 

variables them in the training hospital of Iran university of medical sciences. 

The conceptual frame 

The conceptual frame, of this survey based on concept of participation of decision making 

Definition practice word 

1. participation of Decision making : at this survey the aim of participation of decision making of 

the nurses means, the participate of head nurses at the decision making about to training 

programs, safety occupational health, supply medical equipment and special hospital budget the 

scale of participation of decision making computation from answer to P.D.M questions that will 

be change from 12-60.

356 Maryam Nooritajer, Faezeh Nouroozinjad, Ezatjafarchla, Fatemeh and Hosseini 

2. Individual variables containing: sex, job age, work previous at present section , recruitment 

species, Hospital species. 

Material and method 

For this purpose 94 head nurses are chosen by the classified sampling regarding that all of them are 

working at the training hospitals at Iran university of medical sciences in Tehran city of them have 

more than six month that are working at the present section. The present research is a cross-sectional 

study. The instrument for data collection is Queasier, the scale of intermediation arrangement are likert, 

the questioners complete by head nurses by self report method; for analysis of obtained information 

from descriptive and deductive statistics. As well as variance analysis and correlative coefficient. 

Descriptive sample 

At this survey the most present of age is 53.1 % , the age average are between 36-42 years old. 93.6% 

of head nurses are women. 84% of them are married. The average of record of services at present 

section are 18.61±6.37 years with the rang (2-12) years. The average of years that they work are 

26.61%. 

About variable the average of record of services at the present section ( X ±SD) are 8.36 ±6.4 

years and the ranges are 1-26 years. 94% of head nurses the level of education are B.S., 62.8 of them 

work at ICU section, 20.2% worked at surgery section 16.1% workload internal medicine ,Also the 

most partnership at the level Much is at the at the general hospitals 20% but at specials hospitals is 5%, 

(table 1). 

Table 1: frequency distribution of case according subjects partnership at the training and general hospitals in 

Iran university of medical sciences 2005 

general special total 

N % N % N % 

never 3 8.6 7 11.9 10 10.6 

low 9 25.7 23 39 32 34 

middle 14 40 24 40.7 38 40.4 

much 7 20 3 5.1 10 10.6 

Very much 2 5.7 2 3.3 4 4.4 

total 25 100 59 100 94 100 

df=2 p*=0.05 ҳ=5.735 

Result 

The finding show that the most person %40.4 participations decision making of head nurses are at the 

middle range, (table 2). X =2.64±0.96. Also the most average of participative of derision making of 

head nurses related with training programs. (3.12±0.98) that %44.7 of them has participation at the 

training programs. Also from individual variables only the levels of education r = 0.608 P=

The Assesment of Participation Decisionmaking of Head Nurses 357 

Table 2: frequency distribution of cases according participation of decision making at the training hospitals of 

Iran University of medical sciences 2005 

Participation of decision making measure Number % 

Never (12-21.5) 10 10.6 

Low(21.6-31.1) 32 34 

Middle (31.2-40.7) 38 40.4 

Much (40.8-50.3) 10 10.6 

Very much (50.4-60) 4 4.4 

Total 94 100 

SD = 0.46 X = 2.64 

Maximum=5 Minimum=1 

Table 3: frequency distribution of case according subjects partnership at the training hospital in Iran University 

of medical sciences 

Never Low Middle Much Very 

much 

total X 

N % N % N % N % N % N % 

Safety and occupational health 3 3.2 15 16 32 34 34 36.2 10 10.6 92 100 3.35±0/98 

Work rotation 1 101 8 8.5 31 33 42 44.7 12 12.7 94 100 3/35±0/86 

Use of new technical 3 3.2 15 16 30 31.9 38 40.4 8 8.5 94 100 3/60±1/06 

Use of opportunity Job 10 10.6 26 27.7 34 32.6 18 19.1 6 6.4 94 100 2/16±1/06 

Humans & financial resources 27 28.7 39 41.5 19 20.2 4 4.3 5 53 94 100 2/17±0/98 

Creation of facilities welfares 34 36.2 27 28.7 20 21.2 9 9.6 4 4.3 94 100 2/17±1/15 

Training programs & promotion 5 5.3 17 18.1 42 44.7 22 23.4 8 8.5 94 100 3/12±0/98 

Organization 13 13.8 23 24.5 36 38.3 15 16 7 7.4 94 100 2/79±1/11 

Allocation budget 45 47.9 32 34 13 13.8 1 1/1 3 3.2 94 100 1/78±0/95 

Strategies 17 18 34 36.2 29 30.9 12 12.8 2 2.1 94 100 2.45±1 

Goals appointment 7 7.4 25 26.6 41 43.6 16 17.1 5 5.3 94 100 2.86±0/89 

Equipment purchase 20 21.3 18 19.2 35 37.2 13 13.8 8 8.5 94 100 2.69±1/20 

Conclusion 

For the receive to first aim it means determine the rate participation of decision making of the head 

nurses the rate show the most percent of head nurses 40.4% answers that the average of participation 

are the middle average X = 2.64±0.96 

Michailova (2000) believes that the managers almost oppose to participate of employees at the 

decision making process. At the survey that lever (2001) done, he report that 76.3% of manages the 

rate of participation be decreased but they inclination to participation of decision making. At the 

Harmon (2002) studies 45.3% of answers report that the rate of participation were at the middle rang. 

For the receive to second aim it means determine the rate of participation of decision making 

the head nurses According participate subjects show that the most distinction average participation of 

decision making head nurses relative to employees training programs are 3.12±0.98 and the last 

distinction average participation of decision making related to allocation X =1.78±0.95. also 44.7% of 

head nurses told that the rate of participation of training programs at the middle average. And 5.3% of 

them told they never participation of decision making about training programs. 

Rahnavard (2000) said the most rate participation told this matter that employees have more 

interested for participation of decision making at the training programs in the job environment, that it 

has direct effect on the works and the descriptive about the least participate is about allocation budget 

perhaps the reasons is that allocation budget relate to upper class mangers and the policy and 

unapparent native of budget process. 

The result of analysis data show that one variable (hospital manner) related to participation of 

discoing making X 2 =5.735 , df=2 , P=

358 Maryam Nooritajer, Faezeh Nouroozinjad, Ezatjafarchla, Fatemeh and Hosseini 

Hurmon (2002) studied, show no one of individual variables didn’t relative with participation 

of decision making. 

At the lever (2001) studied show that the sex related at the participated. Also at this study show 

that women are more successful at the decision making than the men. for the received the treating aim 

determine the correlative of participation of decision making of head nurses according individual 

variables it wasn’t significant the most correlation, (r=0.861, p=


ISSN 1450-216X Vol.14 No.3 (2006), pp. 359-371 



Aetiology and Epidemiology of Sever Infantile Diarrhoea in 

Baghdad, Iraq 

E. N. Al-Kaissi 

Elham nafi Al-kaissi: Dept of Pharmaceutics 

College of pharmacy, University of Petra 

P.O.Box: 961343 Amman 1196 Jordan 

E-mail: kaielham@hotmail.com 

Tel. (9626)5715546 – 5715549; Fax: (9626)5715570 

M. Makki 

Mahdi Makki: Pediatric Hospital 

Medical City Hospital Baghdad, Iraq 

M. Al- Khoja 

Maysoon Al-Khoja: Teaching Laboratories, Microbiology Lab 

Medical City Hospital, Baghdad, Iraq 

Abstract 

The epidemiology and aetiology of acute diarrhoeal dehydration in a group of 200 

infants less than two years of age in Baghdad / Iraq were studied. Infants at the age of 7 to 

12 months were found to be at grater risk of acquiring diarrhoea. Stool specimens were 

analyzed using, microscopy, routine bacteriological analysis including culture for 

enteropathogens, enterotoxin bioassay, and enzyme linked immunosorbent assay (ELISA) 

for rotavirus detection. Rotavirus was the most frequent enteric pathogen isolated (29.5%) 

followed by Enteropathogenic Escherichia coli (EPEC) then Campylobacter. Rotavirus and 

other enteric pathogens infections were more prevalent during summer. In about 47.5% of 

the cases, antimicrobial agent was used prior to admission to hospital. A symptomatic 

carriage of Salmonella, Campylobacter, EPEC, Giardia, Entameba were detected in less 

than 5% of cases. Oral rehydration therapy proved to be simple, safe and effective for acute 

diarrhoeal dehydration if prepared correctly 

Key words: Aetiology, diarrhea, dehydration, Gastroenteritis, enteric pathogens, Rotavirus 

Introduction 

Diarrhoeal diseases are a major cause of morbidity in infants and young children in developed 

countries and a major cause of morbidity and mortality in underdeveloped countries [1]. In a family 

study of some 25,000 illnesses in the United States, infectious gastroenteritis was the second most 

common disease and accounted for 16 percent of all illnesses [2]. The impact of diarrhoeal illnesses on 

infants and young children in developing countries is staggering. An estimate of the number of 

diarrhoeal episodes in children younger than 5 years of age in Asia, Africa, and Latin America for a 1year 

period indicated that more than 450 million cases of diarrhea occurred and that 1 to 4 percent were

Aetiology and Epidemiology of Sever Infantile Diarrhoea in Baghdad, Iraq 360 

fatal, resulting in the deaths of 5 to 18 million children [3]. A later study in the same areas estimated 3 

to 5 billion cases of diarrhea and 5 to 10 million diarrhea-associated deaths in 1 year, ranking diarrhea 

first among infectious diseases in the categories of both frequency and mortality, with the burden 

greatest in infants and young children [2]. 

Infant gastroenteritis remains a critical public health problem all over the world as was 

recognized by WHO [3] and acute diarrhea due to bacterial infections is one of the main causes of 

childhood morbidity and mortality especially in developing countries [4]. Despite the importance of 

this disease, the agents of a large proportion of diarrhoeal illnesses of infants and young children were 

not known until relatively recently [2]. 

Up to 70% of the 1400 million episodes of diarrhea worldwide in children under age 5 years 

cause this morbidity and mortality may be due to pathogens which is transmitted through food [5] or 

drinking water [6]. 

Among the causative agents, the following bacteria have been reported: Enterotoxigenic 

Escherichia coli (ETEC), Shigella, Salmonella, and Campylobacter [7, 8]). Among the viruses, 

rotavirus seems to be the most common [9]. Food contamination is one major route for the 

transmission of enteropathogens, especially under the hygienic conditions prevailing in a rural setting. 

Various studies have reported that the source of the enteropathogens was either water or food [10]. 

Rotavirus is the leading cause of severe gastroenteritis among children worldwide [11]. 

Annually rotavirus is estimated to cause 352,000-592,000 deaths, 2 million hospitalizations and 25 

million clinic visits globally among children younger than 5 years of age [12], mortality and 

hospitalization rates vary significantly depending on access to health care in developing settings. 

Depending on the setting and studies, rotavirus was found in 13-71% of diarrhea cases requiring 

inpatient or outpatient medical care in infants and young children [13, 14]. 

Most cases of gastroenteritis have a viral etiology and are self-limited. However, more severe 

or prolonged cases of gastroenteritis can result in dehydration with significant morbidity and mortality. 

This is often the scenario in third-world countries, where gastroenteritis results in 3 million deaths 

annually [15]. 

The main risk of gastroenteritis in children, particularly babies and young children is that they 

become dehydrated. This can occur very quickly in babies because they do not need to lose a lot of 

fluid to lose significant percentage of total body fluid [16]. The most effective treatment and 

intervention method for acute diarrhea and for the control of diarrhoeal mortality has been the use of 

oral rehydration therapy (ORT). The aim of ORT is to restore the initial fluids deficits and to replace 

ongoing stool losses until diarrhea ceases [17]. The ORT fluid composition is presented in table (1). 

New diagnostic laboratory techniques as well as modifications of standard ones have been used by 

investigators to identify viral, bacterial, and parasitic agents of outbreaks of gastroenteritis [18].This 

study was designed to determine the causative agents of diarrhoea in children less than 2 year of age in 

Baghdad / Iraq and to assess the efficacy and safety of using ORT treatment in management of 

infantile diarrhoeal dehydration.

361 E. N. Al-kaissi, M. Makki and M. Al- Khoja 

Table 1: Comparison of Oral Rehydration Solutions 

Solutions 

Glucose Sodium 

Composition 

Potassium Chloride 

Commercial solutions 

(g per dL) (mEq per L) (mEq per L) (mEq per L) 

WHO solution 2.0 90 20 80 

Hydra-Lyte 1.2 84 10 59 

Rehydralyte 2.5 75 20 65 

Pedialyte 2.5 45 20 35 

Generic pediatric solution* 2.5 45 20 35 

Lytren 2.0 50 25 45 

Resol 2.0 50 20 50 

Infalyte 2.0 50 20 40 

Ricelyte Starch polymers 50 25 45 

Home remedies (not recommended) 

Jell-O(one-half strength) 8.0 6 to 17 0.2 -- 

Gatorade 5.0 24 3 17 

Soft drinks 7.0 to 12.0 1 to 7 0.1 to 0.4 -- 

Apple juice 12.0 0.1 to 3.5 24 to 43 -- 

Broth -- 250 -- -- 

WHO=World Health Organization. 

*--Similar to Pedialyte. 

Information from reference (MMWR2003). 


200 cases admitted to the medical city hospital Baghdad/ Iraq for rehydration were included in this 

work, they were children between the age of 0-2 years and their diarrhoeas of less than 6 days duration 

prior to admission to hospital. The study extended for one year. Evaluation of the degree of 

dehydration was performed on admission [19]. ORT (WHO formula- table 1) was offered to all 

patients irrespective of age. 

Laboratory investigation 

A-Blood samples were sent to the Laboratory for biochemical investigation including: serum Na + , K + , 

CL - , BUN, protein(by Technicon- Microlyzer) and acid-base study by Micro-Astup).) 

B-isolation of enteric pathogens 

A total of 200 stool specimens were collected from the children, the specimens were collected in sterile 

specimen bottles having the names and ages of the patients. All the samples were transferred 

immediately to the laboratory for analysis. General stool examinations were done as well as 

inoculation into standard appropriate culture media, Selective and differential solid media as well as 

enrichment broth were used for primary isolation of enteric organisms. These include: MacConkey's 

agar (Oxoid), deoxycholate citrate agar (Oxoid), and selenite F (Oxoid) as enrichment broth for 

entopathogenic Escherichia coli, Salmonella and Shigella as described [20], and Campylobacter 

selective agar, which contains vancomycin, polymyxinB sulphate and trimethoprim (WHO supply) for 

campylobacter species.All solid media plates were incubated aerobically at 35-37ºc for 18h except 

campylobacter selective agar plates which were incubated under microaerobic condition at 42ºc for 48h 

[21]. Biochemical tests such as methyl red, motility, kligler iron agar, indole, catalase, urease and 

oxidase were carried out on the bacterial isolates using conventional techniques of [22]. E. coli 

colonies from non inhibitory agar medium were screened for classical enteropathogenic serotypes by 

the slide agglutination tests using commercially available antisera (Wellcome Diagnostics, Temple


Hill, England). E. coli colonies were also screened for enterotoxin production. Heat-labile toxin (LT) 

was detected by the Biken method [23] using immunodiffusion assay. 

C- Quality controls for laboratory investigation 

Two sets of Quality-control specimens were set up each month by mixing a known quantity of 

bacterial cells of Salmonella, Shigella, and Campylobacter with an autoclaved stool specimen to give 

concentrations in the range of 10 2 to 10 6 per gram of stool. One set was transported to the wards and 

returned via the normal specimen delivery procedures. The remaining set was immediately processed 

for bacterial culture. 

D-Detection of Rotavirus 

Stool specimens were also examined for rotavirus antigens by enzyme-linked immunosorbent assay 

(ELISA). A 10% suspension of each stool sample was made in phosphate-buffered saline and the 

presence of rotavirus antigens was detected by ELISA kits provided by Word Health Organization. 

Samples were examined in duplicate and positive specimens were confirmed by ELISA-blocking assay 

using hyper-immune rotavirus antiserum as described by Beards and others[24]. 

Blood culture was done when it was possible 

One hundred stool specimens were collected from children under 2 years of age admitted to the 

hospital for other illnesses and were used as control group, these specimens were tested for the 

presence of entropathogens provided that they did not show diarrhoea two weeks before and another 

week after taking the specimens for examination. 

ORT (WHO formula-Table 1) 100ml/Kg/4h was given for rehydration in which breast milk or 

diluted milk formula was administered alternatively with ORT until diarrhoea diminished. 

Antimicrobial agents were given to patients with Shigella, Campylobacter and parasitic infestation. 

The evaluation of the clinical picture in general, and the state of hydration in particular, was done every 

4 hours in the first 24 hours, and then less frequently after that. 

Results 

The present study reveals that 68(34%) of the admitted cases were severely dehydrated and the rest 

132(66%) were moderately dehydrated according to the WHO & MMWR [19, 25] classification. The 

group studies was composed of 108(51%) male and 92(49) female. 

Seasonal incidence: 44% of the cases were occurred during summer and the lowest rate was in 

winter (14.5%) as was shown in Figure (1)


percentage 

50 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

14.5 

Winter 

Figure 1: seasonal incidence 

16.5 

Autumn 

44 

Summer 

25 

Spring 

Column 1 

Age incidence: about 76.5% of the cases were occurred in children under one year, and 

23.5%of the cases occurred in children with 1-2years of age (Figure 2). 

Percentage 

50 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

1 

Figure 2: Age incidence in months 

30.5 

45 

23.5 

1 M 1-6 M 7 - 12 M 13 - 24 M 

Methods of feeding were shown in Table (3) & Figure (3). 

Column 1


Percentage 

40 

35 

30 

25 

20 

15 

10 

5 

0 

37.5 

30 

Figure 3: Types of feeding 

17 

15.5 

Artificial Breast Mixed Solid 

Column 1 

Antimicrobial intake prior and after admission: 47.5% of the cases, antimicrobial agent was 

used prior to admission, 34.5% had one, 12% had two and 1% had three (Figure 4).After admission 

15% had specific antimicrobial treatment because their stool examination revealed campylobacter 

species, shigella species, Giardia lamblia and Entamoeba histolytica. Three patients received 

antimicrobial treatment for they shows blood culture positive results. 

percentage 

50 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

47.5 

total 

Figure 4: Antibiotics intake prior admission 

34.5 

one antibiotics 

12 

two antibiotics 

1 

three antibiotics 

Column 1 

Macroscopic examination of 200 diarrhoeic stool specimens revealed that: Blood were found in 

7.5%, pus in 11% and mucus in 6% in stool specimens of liquid consistency as compared to semiliquid 

(Table 2)


Table 2: Macroscopic appearance of stool specimens 

Visual examination 

Stool consistency 

Total 

Liquid Semi-liquid 

No. % No. % No. % 

Blood 15 7.5 5 2.5 20 10 

Pus 22 11 13 6.5 35 17.5 

Mucus 12 6 4 2 16 8 

Blood+Pus+Mucus 4 2 1 0.5 5 2.5 

None 26 13 98 49 124 62 

Methods of feeding: Table (3) shows that 30% of the admitted cases of diarrhea were 

exclusively on breast milk. The rate gets higher 35.5% when children over one year of age were 

excluded. 

Table 3: Methods of feeding 12 months of age in mild, moderate-severe cases 

Methods of feeding 

Mid cases Moderate sever cases Control cases 

Number Percentage Number Percentage Number Percentage 

Artificial 568 28 68 44.4 25.4 39 

Mixed 405 20 31 20.1 13.4 20 

Breast 1055 52 54 35.5 61.2 94 

Total 2028 100 143 100 100 153 

Staying in hospital and outcome: No single mortality was reported in this study, the range of 

the staying in the hospital was 1-7 days, with an average of 3.1 days. The family responding toward 

staying is recorded in Table (4) were 66% of the families had stay for adequate time and 13% refused 

to stay. 

Table 4: family behavior toward staying in ORT center 

Family behavior Number of families Pecentage 

Refuse to stay in the ORT center 26 13% 

Stay inadequate time ≤2h 36 18% 

Stay inadequate time≥2h 132 66% 

Referred to hospital ORT failure 6 3% 

Total 200 100 

Blood culture: It was able to draw enough blood for blood culture in 78.5% of the cases. Three 

cultures only turned out significantly positive and Salmonella typhi, Salmonella paratyphi and E. coli 

were isolate. The rest of the cultures were either negative or contaminated bacteria were isolated. 

Aetiology of diarrhea 

(A) Isolation of enteric pathogens and quality control specimens 

Enteric pathogens contained in the quality control specimens who were transported through the 

specimen delivery system were regularly recovered. These included the more fastidious organisms 

such as Shigella and Campylobacter. Most of bacterial pathogens can be re-isolated at concentrations 

of 10 2 or higher organisms per gram of stool except Campylobacter which were usually isolated at 

concentration of 10 4 or higher organisms per gram of stool. These procedures were employed to assess 

the effect of transportation on the efficiency of isolation of enteric pathogens in the laboratory and also 

to act as an internal control for the methods of isolation of these pathogens.


(B) Frequency of isolation of enteric pathogens 

The frequency of isolation of various enteric pathogens from diarrhoeal patients enrolled in the 

prospective study was compared with the control as shown in Table (5) 

Table 5: Prevalence of enteric pathogens isolated 

Aetiology Number of patients with pathogens isolated Number of healthy control with pathogens isolated 

Number Percentage Number Percentage 

ٌRotavirus 59 29.5 0 0 

EPEC 25 12.5 1 1 

ETEC 5 2.5 0 0 

Campylobacter 14 7 4 4 

Salmonella 11 5.5 5 5 

Shigella 6 3 0 0 

Giardia 6 3 3 3 

H.histolytica 4 2 2 2 

Mixed 9 4.5 0 0 

Unidentified 61 30.5 85 85 

Total 200 100 100 100 

Human rotavirus and bacterial pathogens were detected in 29.5% and 35% of the 200 episodes 

of diarrhea in the study group of infants respectively. 

Rotavirus was the most frequently isolated pathogen (29.5%) which was detected by Enzyme 

linked immunosorbent assay (ELISA) test and confirmed by ELISA-blocking assay, followed by 

EPEC (12.5) and Campylobacter jejune (7%). Salmonella was isolated in 5.5% then Shigella (3%), G. 

lambelia in 3%, ETEC 2.5% and E. histolytica in 2% respectively. Diarrhoea with unknown aetiology 

accounted for 30.5% of the episodes (Figure 5). 

percentage 

35 

30 

25 

20 

15 

10 

5 

0 

EPEC = enteropathogenic E.coli 

Camp = Campylobacter 

Salmon = Salmonella 

Shig = Shigella 

Giard = Giardia 

ETEC = enterotoxigenic E. coli 

E.hist = E.histolytica 

30.5 29.5 

no ne 

Ro tavirus 

Figure 5: Percentage of pathogens isolated 

12.5 

EP EC 

7 

Camp 

A symptomatic carriage of Salmonella ,Campylobacter, EPEC, Giardia, Entameba were 

detected in 5%,4%, 1%, 3%, 2%, of healthy infants respectively. Rotavirus was not detected in 

asymptomatic infants. Asymptomatic carriage of ETEC and Shigella was not detected 

5.5 

Salmon 

Shig 

3 3 2.5 2 

Giard 

ET EC 

E.hist 

East 

West 

North


No pathogens were isolated for 30.5% of diarrhoeal cases; some of these cases may be caused 

by other enteric viruses or parasites which were not investigated. 

Discussion and Conclusion 

Gastroenteritis in children is a common reason for visits to family physicians. Most cases of 

gastroenteritis have a viral etiology and are self-limited. However, more severe or prolonged cases of 

gastroenteritis can result in dehydration with significant morbidity and mortality. This is often the 

scenario in third-world countries, where gastroenteritis results in 3 million deaths annually. Some 

problems still exist in Iraq in educating the public and professional on the new concepts of diarrhoeal 

management as oral rehydration and continued feeding. This has been reflected in the presence of a 

large number of parents who refused or were reluctant to accept this approach of therapy (Table 4). 

Most children with gastroenteritis can be treated with physiologically balanced oral rehydration 

solutions [15]. In children who are hypovolemic, lethargic and estimated to be more than 5 percent 

dehydrated, initial treatment with intravenous boluses of isotonic saline or Ringer's lactate may be 

required. Children with severe diarrhea need nutrition to restore digestive function and, generally, food 

should not be withheld [15]. 

Prevalence of diarrhea during summer season is a common feature of tropical and subtropical 

countries and occurred more in infants under one year of age (Figure 1) similar findings were reported 

by [26]. Others reported that there is marked seasonal variation in occurrence of infection with peaks of 

incidence during summer and autumn [21]. 

The association of faecal leucocytes with organism known to penetrate intestinal mucosa such 

as Shigella species and EPEC was noted in this work. Similar findings were reported by others [27, 28, 

and 29], so the importance of direct stool examination of patient with diarrhea was reemphasis in this 

work. 

The maximum incidence (45%) of gastroenteritis occurs in patients with 7-12 month of age, the 

same results were reported by Ballal and Shivanada in 2002[30]. 

Diarrhea caused by Rotavirus was detected in 29.5% of the diarrhoeal children, the infection 

exhibited a marked seasonal distribution, with most of the cases occurring during the summer, and 

other similar studies undergone in Basrah (southern part of Iraq) have reported that Rotavirus 

admissions and isolation rates were highest during late winter. Khetsuriani, and Parashar reported in 

2002[31] that in temperate climates, rotavirus disease predominantly occurs during the fall and winter 

months, a study from Japan showed that, unlike in children, rotavirus diarrhea in adults did not show 

significant winter seasonality, in the United States, rotavirus activity peaks in the Southwest in autumn 

(October through December) and migrates across the continent, peaking in the Northeast during spring 

(March through May), in tropical settings, rotavirus disease occurs year-round [31].These may be due 

to weather and social differences, most of the salmonella isolated were serotype B, C, or E. infections 

with these organisms appeared to occur as isolated outbreaks (Figure 1). 

Aetiology of diarrhoeal disease in Baghdad 

Results showed that food-borne infections due to Salmonella and Campylobacter are significant. Low 

numbers of Salmonella species may also be isolated from the faeces of healthy asymptomatic carriers, 

asymptomatic carriage of these organisms is common and they were also important causes of infantile 

diarrhea. Salmonella are mainly transmitted via dairy and meet products [32]. Poultry is believed to be 

an important reservoir for Campylobacter [33]. Infections with these organisms have been increasingly 

prevalent in recent years which coincide with increases poultry production in Baghdad. Rotavirus is the 

most common of the enteric pathogens isolated (29.5%), other similar studies [34] have reported that 

Rotavirus was detected in 28.5% of diarrhoeal children aged 5 years or under, other investigation in 

Basrah by Mahmood and Feachemt in 1987[35], Rotavirus was detected in 24% of cases. As 

previously reported the virus population is genetically diverse and varies with time [34]. In the present


study, a large majority of the infants developing rotavirus diarrhoea were at age when the infants 

would have little contact with other children. Increases incidence of rotavirus infection was associated 

with infants who were breast-fed and who were nursed by their mothers, rather than by others. 

Although adults rarely suffer from rotavirus diarrhoea, it has been shown that the level of serum 

rotavirus antibodies increases with age in females, reaching a peak during their child-bearing years 

[36]. 

EPEC is second to Rotavirus as the most common of the enteric pathogens isolated, other 

similar result was reported by [37]. 

Infection by Rotavirus and Salmonella are more important clinically than infections due to 

Campylobacter which has a shorter duration, although it was uncommon that the above described 

infection may be complicated by secondary infection and this usually resulted in more protracted 

diseases with greater loss of body weight. 

Over third of the diarrhea episodes presently investigated had no identifiable cause. Some of 

which were presumably of a non-infectious aetiology while others may have been caused by enteric 

pathogens not presently investigated. The latter may include other enteric viruses such as adenovirus 

and Norwalk agent, or other parasites. 

Age presented as a prominent factor influencing the frequency of isolation of enteric pathogens 

associated with diarrhea. The majority of the infection occurred between 7 and 12 months of age, 

isolation of enteric pathogens exhibited 3 peaks, at 7-12 months(45%), 1-6 months(30.5%) and 13-24 

months of age(23.5%) respectively. These age periods corresponded with the times when infants were 

being nursed, after they had been weaned and when they began to walk. Presumably diarrhea occurring 

during the first two periods may be chiefly due to food-borne infections, while the environment may 

provide additional sources of infection when the infants begin to walk. Consequently, personal and 

food hygiene may be expected to be important influencing factors in the development of diarrhea 

during early infancy, and this may be the reason to had a high findings results detected in Ethiopia 

were Rotavirus detected in 49% EPEC in 19% and Campylobacter in 13% [37], a different result were 

reported by Mahmood & Feachemt in 1987[35] as the peak admissions of all infantile diarrhea 

occurred in the 2-3 months age group. 

Thirty years ago the aetiologic agent used to be undetermined in the majority of acute 

diarrhoeal infections. Recent advance in the laboratory techniques had remarkable increased the 

recovery rate of significant enteropathogens in the stool of patient of patient with diarrhea. Rotavirus, 

Campylobacter, and ETEC were considered the most significant newly discovered enteropathogens 

[14, 9].The most frequent enteropathogen recovered in this study , as in most similar studies, was 

Rotavirus , the present isolation rate for campylobacter is considered about the average for developing 

countries which is in the range of 5-13% [37]. The isolation rate of pathogenic E. coli were 12.5% and 

2.5% for EPEC and ETEC, it could be higher if we had facilities to recover heat labile ETEC. Positive 

blood culture seemed to be rare in this studied cases 93 out of 157). Thus routine blood culture is 

probably an unnecessary procedure for management of acute diarrhea. 

Antimicrobial therapy was used prior to admission in 47.5% of the present cases.This rate is 

higher than the unacceptable high figure (40.3%) reported in this country before [38].With the 

exception of certain invasive bacterial and parasitic infections there is no evidence that antibiotics can 

reduce fluid loss in diarrhoeal diseases. It is justifiable to administer specific antimicrobial therapy for 

Shigella, campylobacter, G.lamblia and E. histolytica infections. Otherwise blind antimicrobial therapy 

would not be beneficial in the majority of patients and possibly harmful in others [39, 40]. 

Many pediatrician over suspected septicaemia on clinical ground to give themselves 

justification for giving intensive antimicrobial agent treatment , forgetting that the sever clinical 

manifestations appearing on their patients are most likely due to pathophysiological disturbances 

associated with diarrhea rather than to septicemia. 

Prevention of diarrhea requires vast, complex and expensive medical, sociological and 

environmental improvements designed to reduce contact of enteric pathogens, increase awareness of


the importance of personal hygiene, and advise effective treatment for acute diarrhea and active 

immunization against enteric pathogens. 

ORT has fulfilled the basic core of the control measures for acute disease management. The 

next stages will involve socioeconomic improvements in the provision of clean food and water, and 

educational elements for personal hygiene, and nutritional improvements. 

Results obtained from the present study showed that diarrhea is a common disease in children 

under 2 years of age, the financial losses due to medical care and loss of working hours for parents 

whose children are suffering from diarrhea is incalculable. Control measures such as public health 

education on personal hygiene, the new concepts of diarrhoeal management (oral rehydration and 

continued feeding) and improvements in living conditions should be introduced to further reduce 

diarrhoeal morbidity in Baghdad.


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ISSN 1450-216X Vol.14 No.3 (2006), pp. 372-387 



Islam and Education from Religious Man’s Perspectives 

Nazenin Ruso 

Educational Sciences, Eastern Mediterranean University 

Gazimagosa, Turkish Republic of Northern Cyprus 

Via Mersin 10 Turkey 

E-mail: nazenin.ruso@emu.edu.tr 

Telephone 0392-630-2920; Fax: 3651584 

Abstract 

The present descriptive study investigates the observable effects of education on 

religion in TRNC from Imam’s (religious men’s) perspectives. Although the primary 

concern of the study is to see if there is a link between educational and religious values, the 

study presents a detailed description on the interests shown to religion and education in the 

country. Furthermore, the study investigates whether these values may change if TRNC 

joins to European Union. In this study, mainly a qualitative approach is adopted and 132 

Imams (religious men) from local mosques in Northern Cyprus responded to the openended 

questionnaire prepared by the researcher. The data analysis involves a comparative 

reading of the Imams’ opinions about education and Islam investigated through 

questionnaire. The findings of the study reveal that there is no observable effect of 

education on religion. Moreover, the findings of this study emphasizes the importance of 

religion for the development of a country but it Imams reported being disappointed in the 

interests shown to religious requirements such as attending to mosques. Another conclusion 

of the study reveals that nowadays, the youth started to loose many values but the 

unification of the island and Turkish entry into the European Union might have a beneficial 

effect on raising the religious level of Muslim Cypriots. Finally, participants in the research 

suggest that our educational and religious values will improve if we join to European 

Union. 

Purpose of the Study 

TRNC is a secular and modern community following Ataturk’s reforms, who is the biggest figure who 

established secularism for Turkish people. Since Ataturk’s death, Turkish Cypriots have followed the 

religious practices for Turkey. All Turkish people accepted Islamic religion conveyed through 

Muhammad’s teachings and Holy book Koran. Although the state of Turkish Republic of Northern 

Cyprus (TRNC) supports Islamic religion, it is observed that in TRNC religious interests became a 

matter of private conscience. The purpose of the study is to find out how Imams view education and 

religion. 

Literature Review 

After reading relevant literature on the topic, several research questions aroused. This section presents 

the literature review on the topic and tries to show why certain questions were asked. First of all, the 

literature review reveals that what is meant by the word Muslim is a controversial issue on the island 

because the word “Muslim” means different to different people in TRNC. According to many religious

Islam and Education from Religious Man’s Perspectives 373 

sources including a website on Cypriot Information Resource “the word Muslim means one who has 

surrendered to God’s will”. God’s will consist of five pillars of Islam which are daily prayers, fasting 

during Ramadan, almsgiving, visiting Mecca and to believe in God and Muhammad as his messenger. 

However, the understanding of the word “Muslim” is completely different for people living in TRNC. 

“What is meant by the word “Muslim?” is one of the research questions. As the focus of this paper is 

describing Islam and education from Imam’s perspectives, I felt the need to clarify these terms first 

according to Imam’s definitions. Within the light of these clarifications, I tried to display a more 

conscious interpretation of the data. 

Like the word “Muslim”, the word “Education” is a very broad concept and it can be 

interpreted in a variety of ways. A check on some Islamic resources reveals various interpretations with 

regard to Islam. Seyh Nazim is a very important religious figure in Cyprus who points out that 

knowledge comes from heaven. For Seyh Nazim and his followers, the most ambiguous issue is to see 

how an educated person can claim that there is no God. During a discussion, Seyh says that the world 

is covered by ignorance and at the top of this ignorance are those people who deny the existence of 

God. (Atay, 1996, p.184). “What is meant by the word education?” is another research question. 

Although the devout Muslims define being Muslim as mentioned earlier, many Turkish 

Cypriots, specifically those who are academics claim that they do not have time to practice their 

religion due to their educational requirements but their heart is clean and that is the most important 

thing for a Muslim. At this point an important question arises: “Is clean heart really the most 

important thing for a Muslim?” 

Apparently, the number of educated people increases day by day and according to several 

official researches, education is causing people move away from religion. For example, Carkoglu 

&Toprak(2000) found that while the education level of people increase, the number of people who 

claim that they are not religious increases. Is this true? At this point I added a new research question as 

“Do you think university and above education is causing people to move away from religion? If yes, 

what sort of people? Why?” 

There is a belief that education causes modernization and there has always been a conflict 

between tradition and modernization. Like in many parts of the world, TRNC is also abandoning some 

of its old traditions to be able to adapt modernity and global ascendancy of the West. As reported in an 

article on Reframing Orientalism: Weber and Islam, the incorporation of “Muslim society” into the 

“global society” of the past two hundred years is felt among Turkish people. This incorporation has 

caused a rise in secularization and modern interpretations of Islam. Another article on cosmopolitan 

virtue() further discusses the issue of secularization and relates it to educational systems by claiming 

that “It is clearly true that Islamic fundamentalism has rejected differentiation by attempting to enforce 

religious law over the operations of secular institutions such as educational systems.” These different 

observations about globalization are insightful but do we know how do Imams in TRNC define the 

words “globalization” and “modernization” and if they think globalization and modernization are 

causing people towards or away from religion? 

Islamic religion is the second most important religion in the world. A website on religion states 

that ”Everyone in TRNC has the right of religious freedom in teaching, worship and observance, 

without any interference from the state.” Although Turkish Cypriots reflect Islamic tradition for about 

400 years through celebrating bairams, the value given to religious practices required by Islam is 

decreasing everyday. The same website adds that “Approximately 10 % of the population in the north 

attends religious services regularly” and Muslims make up 99% of the TRNC. Considering this 

percentage, several questions can be asked such as “Are we starting to loose any of our values? Which 

ones? Why?”, “What can be done by the religious establishments to overcome this problem?” , “What 

percentage of the mosques capacity are full?” and “When do the people go to mosque nowadays?” 

One website on Turkish Society points out that Ataturk’s reforms brought modernity for 

Turkish culture by claiming that “Under Ataturk’s leadership, the ideological, secularist and modernist 

urban elite ended state support and patronage of Islamic institutions and attempted to make religion a 

matter of solely of private conscience”. The same site adds that Ataturk’s reforms created two different

374 Nazenin Ruso 

cultures for Turkish people. The first is a secular Western elite culture and the second one is a mass 

culture emphasizing traditional values. Moreover, it is observed that there are mainly two major 

communities living in the TRNC which are Turkish people from Turkey and Turkish Cypriots who are 

all Muslims. Although both communities embraced the values of secularity, the mainly religious 

observant mass in TRNC are Turkish people who come from Turkey. Turkish Cypriots are seen as 

more modernized whereas Turkish people are seen as more traditional. The conflict here arises as it is 

pointed out in The Society website as :“The cultural difference between the educated and the 

uneducated, the urban and the rural, the modernist and the traditionalist, has continued to affect 

Turkish society in multiple, intertwined ways”. Another important research question arises from this 

quotation: 

“Who are the people who go to mosques to fulfill their religious requirements? Turkish 

nationals/ Turkish Cypriots /Literate/ Illiterate/Old/ Young/Poor/ Rich?” 

If there is a decrease in the number of Turkish Cypriots visiting to mosques, can it be because 

of the lack in religious education? Elder people on the island state that religious education was 

different in past. “How was religious education in past?” is a potential question at this point. A check 

on relevant sources reveals that in past, there were Muslim schools run by Evkaf. A Cypriot 

Information resource state that “Whereas the Vakif operated Muslim schools in the past, in recent 

decades it has simply provided funds for the salary of mufti, the highest religious figure, and for the 

construction, repair and maintenance of the mosques”. Different websites on TRNC and religion 

speculate that religion is a free, personal choice on the island. For example, the same Cyprus 

Information Resource reports that religion is a personal matter among Turkish Cypriots, and they never 

attempt to impose their religious beliefs on others. Likewise, another website source on Cyprus quotes 

“In the northern part of the island, the Turkish Cypriot basic law refers specifically to a ‘secular 

republic’ and provides for religious freedom; no specific religion is recognized in the basic law.” 

After finding about religious education in past, one needs to ask “How do children get their 

religious education now?” to be able to see if there is a difference between the education methods 

applied in past and present. Nowadays, there is religion instruction in primary school system in TRNC, 

but it is only a passive instruction without actually showing religious practices in detail to children. 

Ataturk initiated a secularized and modernized education system. The article on “The roles of state and 

religious instutions in the Turkish education system” by Adam Keyes illustrates the extent of this 

interest by giving the aims of the Turkish educational system from Ataturk’s perspective. Keyes states 

that “The aim of the Turkish educational system was now to create productive citizens with 

contemporary educational standards. His ideal was to move away from tradition and move towards 

modernization and globalization.” 

On the other hand, especially some old people complain about the new education system which 

is quiet modern and doesn’t emphasize religious values. They say that considering past, nowadays, all 

discos and bars are full of young people who do not spend time for their religious activities. Some 

religious authorities like Seyh Nazim complain about the new modern education establishments 

predicting that modern education establishments are guiding students not to believe in anything (Atay, 

1996, p.189). For them what prepares a person for a virtuous life is not science but morality. So, before 

knowledge morality should be valued (Atay, 1996, p.186). On 8 th of April, 1992 during one of his 

speeches in Dergah, London, Seyh is addressing parents and asking them “Why don’t you prepare your 

children for a moral life. Do you think that bars can teach your children anything about moral life? 

This is why God’s blessings came to an end” (cited in Atay, 1996, p.190). Similarly, Berkes (1998) 

speculates that the destruction of traditional children’s schools caused the destruction of the 

foundations of Islamic education which in turn caused a moral collapse. So, there is a big conflict 

between the beliefs of the religious people and modern people concerning their expectations from the 

educational system. At this point, several questions arise: “How should children get their religious 

education outside of the school? What can be done by the families? What can be done by the 

government?”


The writings which reflect Ataturks’s ideas all promote a modern Turkey which sees Europe as 

an example. A website on The Society indicates Ataturk’s plans for Turkey and quotes that “He 

actively promoted a ‘modern’ Turkey that embraced the civilization of Europe as its inspiration and 

model.” However, some books such as “Islam in a Laic World” claim that modern countries do not 

have one religion. So, Turkey as a modern country can have other religions than Islam. Ozturk(1998) 

argues that a modern government is a government which does not require only one religion can 

recognize more than one religion and respect all. Nowadays, we are coming more close to join 

European Union every passing day. “What do Imams think about joining to European Union? Will our 

religious and educational values be affected if we join to European Union?” are the other potential 

research questions at this point. 

Methodology 

The research approach of this study is qualitative approach as the method mainly used aims to obtain 

information about human through interpreting language generated by data collected. In terms of 

methodology, the current research proceeded in three phases. First of all, after reading relevant 

literature on the issue, an open-ended questionnaire was prepared and the questions were asked to a 

few Imams to get feedback. Secondly, the questionnaire was modified according to the feedback given 

by Imams, the research advisor and colleagues and was administered to all Imams in the country with 

the help of the director of Religious Affairs Office. 132 Imams who were from different ages, regions, 

education levels and different years of service but mainly from Turkey responded to the questionnaire 

without having any idea of the identity of the researcher who is a young modern female instructor☺ 

This would have affected their answers. Thirdly, the answers of a question regarding identifying the 

picture of majority of people who attend to mosque were entered to the computer to draw pie charts out 

of the frequencies. Finally descriptive statistics are run for another question too see how full are the 

mosques and on which occasions people visit mosques more often. 

Research Questions 

Your Age: 

Your Education Level: 

Years of service as an Imam: 

Turkish Cypriot/Turkish National: 

1. Why did you choose this occupation? 

2. Are you working in a village or city? 

3. What is meant by the word “education” for you? What should it involve? 

4. What is meant by the word “Muslim” for you? 

5. Many Muslims who do not practice their religious requirements claim that the most important 

thing for a Muslim is to have a clean heart? What do you think about this? 

6. Do you think university and above education is causing people to move away from religion? 

If yes, what sort of people? 

Why? 

7. What are meant by the words “globalization” and “modernization” for you? 

Do you think globalization and modernization are causing people towards or away from 

religion? Why? 

8. Are we starting to loose any of our values? Which ones? Why? 

What can be done by the religious establishments to overcome this problem? 

9. Considering our society’s fulfillment of religious requirements, underline the appropriate 

answer for you. 

Majority of people who come to your mosque are: 

a) Turkish national/ Turkish Cypriot


b) Literate/ Illiterate 

c) Old/ Young 

d) Poor/ Rich 

10. The number of people who continuously attend your mosque ________ 

The capacity of your mosque ________ 

Please put numbers next to the times your mosque is most crowded by indicating 1 as the most 

crowded? 

a) Everyday 

b) Friday prayers 

c) Bayram prayers 

d) At “Kandil” nights/ Special nights 

e) At Ramadan/ At “Teravi” 

11. Have you realized any increase or decrease within the number of people who attend your mosque 

in the recent years? 

If yes, what do you think is the reason behind this? 

12. How was religious education in past? 

13. How do children get their religious education now? Do you know which topics are taught at 

school? What can be done to improve the religious education of students at schools? 

14. How should children get their religious education outside of the school? 

What can be done by the families? 

What can be done by the government? 

15. What will happen to our religious values if we join to European Union? 

16. What will happen to our educational values if we join to European Union? 

Findings 

Information about Imams 

Firstly, Imams in Cyprus choose their occupation mainly to fulfill the religious needs of their society 

members, to provide peace and ease for the society, to help the continuation of Islam religion to fulfill 

the duties of God and Prophet. However, it should also be added that there are a few Imams who chose 

their occupation as it is an easy and a guarantee government job due to monthly salary. For some of the 

Imams, being an Imam is a family job for about four hundred years. Majority of the Imams are 

graduates of religious schools such as “Imam Hatip Lycee” and “Theology Faculty”. It should be noted 

that Imams value education a lot. There are some Imams who graduated from two different universities 

and some completed their MA degree, as well. Only around 10% of the Imams are primary school 

graduates. Imams reported that the best person is the person who can deal with this world and afterlife 

at the same time and they have the chance to provide religious information to people. Almost all of the 

Imams pointed out that they are very happy with their jobs because the concept of religion is the most 

effective solution to all kind of social and spiritual problems in life. Their happiness is related with 

being unique in carrying out such a divine occupation. An Imam believes that it is extremely difficult 

to express his religious emotions on his divine duty and compares this difficulty as explaining the taste 

of honey to a person who never tried honey and adds that a person has to live these emotions by 

devoting himself to religion. 

Imams Definition of Education 

Then the Imams were asked to define the meaning of the word “education” and what it should involve. 

Too many comments are made to this question concerning education. Imams define education as the 

best investment made for human beings. For Imams life without education is not possible. Even eating 

bread requires education and the role of parents is vital in the process of education. Most of the Imams 

define education as identifying irregularities and making them regular, changing rudeness with


politeness, the attempt of trying to become a good person both in this material world and in the 

spiritual world we will all join after death. 

Moreover, they view education as a period that starts with cradle and continues till grave and 

among all creatures in life, human being is the only creature who needs education extremely. That is 

why the prophets came with the books to educate humans. Imams say that education is learning, adding 

that the first requirement of Koran was to “read” to emphasize the importance of education for a 

Muslim. In Koran, Zumer verse 9, it says:“Can those people who know be the same as who do not 

know?”. This is given as another good example to show the importance of education in Islam. 

According to Imams, God defines knowledge as light and ignorance as darkness and education as the 

end of the ignorance. 

Education should involve…. 

Furthermore, Imams claim that the word education should involve various things such as learning the 

Muslim culture, gaining experience on everything, to read and write, studying science, to be open to 

new developments, to follow technology, to love, to respect others, to behave appropriately, to have 

self-confidence and to be a useful society member. From some of their perspectives, the focus of 

education should be to reveal humans the rationale behind their own creation existence and living in 

this world. Apparently, Imams do not only indicate that education should involve the character 

treatment of a person but also science knowledge, as well. They predict that an educated person can not 

harm anyone. Furthermore, many Imams believe that a person should improve, renew and educate 

himself/herself as if he will never die but work as if he will die tomorrow. 

Imams definition of the word “Muslim” 

Imams define the word “Muslim” as a person who is surrendered to God, who fulfills five pillars of 

Islam and who prays aloud. A Muslim person adores God, Prophet and angels, acts as an example 

member of the Muslim society, has got cultural intelligence and contemporary civilization. A Muslim 

should not only be honest in his/her religious beliefs but also in politics, law, trade and in business life 

as well. Only then he is accepted as a Muslim. One other aim of Islam is to make people act as mature. 

In short, majority of Imams repeated saying that a Muslim should be a mature, honest, respectable, 

clean person who should also be devoted to his nationality and religion as well as his culture and 

traditions. According to one of our hadith interpreted by Buhari, Muslim is defined as “a person who is 

confident from another person’s hand and tongue”. 

The Importance of Having a Clean Heart 

Many Muslims who do not practice their religious requirements claim that the most important thing for 

a Muslim is to have a clean heart. Majority of Imams accept that clean heart is a priority for our 

religion but add that it should reflected to the outside by worship. Another Imam feels that everything 

starts from heart and adds that heart is like a small tree which needs to be watered to grow up. 

Similarly, a heart needs to be watered by carrying out religious requirements. An Imam makes a 

comparison on this issue by saying that a body needs water and soap to be clean and similarly a soul 

needs worship in order to be clean. When we worship, we show our thankfulness to God. The 

fulfillment of our religious requirements displays the beauty of being a Muslim. However, at this point 

majority of Imams confirmed that there is no forcefulness in our religion and it is not fair to judge a 

person considering his/her worship. This issue is between God and his human beings. 

On the other hand, a few Imams reacted to this question by saying that those people who do not 

worship are lazy, anti Muslim people. Saying that “my heart is clean” and doing nothing in terms of 

religious requirements is meaningless for them. One Imam clarifies the issue with the help of a verse 

from Koran. He says that in our holy book, there is Red SURESI verse 28: “Heart can only relax by


thinking of God”. The same Imam adds that it is impossible for a person to have a clean heart if he/she 

doesn’t believe in God. 

The effects of University and Above Education on Religion 

Imams were asked whether university and above education is causing people to move away from 

religion. This is one of the questions majority of Imams reacted. Most of them indicated that religion 

contributes a lot to the education and improvement of a person. The profile of an educated person is the 

one who is aware of the importance of religion in life. It is very difficult to cheat an educated person or 

to guide him to wrong ways because an educated person is a person who knows how to think. A person 

who thinks always finds the truth. Our religion is very appropriate for science and logic so how can a 

university graduate reject such a logical religion which highlights the importance of goodness all the 

time? Educated people reflect light to the people who are close to them. One of the Imams gives Zumer 

verse 9 from Koran as an example, “Can a person who knows be the same as a person who doesn’t 

know?”. Our master Mohammad said that science is endless so science should be studied from cradle 

till grave. One Imam gave Japan as an example to support the importance of education in the 

improvement of a country. According to him Japans are not only the most religious people in the world 

who are very keen on their traditions and all kinds of religious requirements, but also the most 

technologically developed country in the world as well. A community without a religion can not 

survive. Another Imam gave Americans as an example. He said that, on American Dollar it says “In 

God We Trust” which shows Americans trust and admiration to God. Moreover, he added that when he 

thinks of America as a very rich, economically powerful country, he questions the reason behind this. 

However the answer is very simple: Their beliefs in God which can be seen on their money. 

On the other hand, there were a few Imams who claimed that university and above education is 

causing people to move away from religion. One reason for this is given as the content of the courses 

which are related with materialistic behaviors rather than religious issues. The second reason is the 

difficulties of youth caused by university life such as stress. Due to these difficulties, youth try to get 

rid of stress by behaving in a morally unacceptable ways such as drinking too much alcohol, using 

drugs, etc. 

The effects of Globalization and Modernization on Religion 

Imams were asked to discuss whether globalization and modernization are causing people move 

towards or away from religion. Half of the Imams were in favor of globalization and modernization 

pointing out that Islam advices people to live modern, to love people, to embrace and to protect people. 

They indicate that the growing technology is the proof for the power of God so people should move 

towards religion and admire God more after seeing all these new creations of God. 

However, the other half of the Imams claimed that modernization and globalization are causing 

people to move away from religion. These Imams see a strong relationship with technology and 

modernization. They claim that the world is diminishing now because of technology. People are 

imprisoned in their homes sitting all day in front of their computers and televisions. Especially, this 

situation affects children in a negative way as they have an access to all harmful information via 

computers. However, in past, children used to learn useful things only from their parents and 

accordingly used to behave in a more morally acceptable manners. For some Imams, there is another 

reason for thinking that modernization and globalization are causing people to move away from 

religion. That is the increase in socialization process of people caused by the increase in modernization. 

Imams feel that modern people are social people who experience things that are against our religious 

values such as using alcohol. 

There were also a few Imams who couldn’t see any link between religion and modernization. 

They claimed that modernization is a technological development and has got nothing to do with the 

concept of religion. For them, we are not technologically developed due to our ignorance not due to


our religious values. One Imam pointed out that according to a research he read recently, each Japanese 

reads approximately 70 books a year and each American reads about 60 books a year whereas each 

Turk reads about 4 books a year. This proves our ignorance as a society. Our ignorance is not related 

with our religion. 

Our Lost Values 

Imams were then asked whether we are starting to loose any of our values? Which ones? Why? All 

Imams thought that we are loosing many of our values. One of them answered this question by raising 

another question: “Do you think still there is any value we haven’t lost?” and this question can be 

interpreted as we lost all our values. Imams all agreed on that the youth lost the value of respect. They 

all complained about the youth claiming that they neither respect their parents nor elder people. They 

lost the feeling of love as they started not to visit their relatives during religious days, bairams. Imams 

added that the youth see European countries’ people as example for themselves and admire them for 

being so free. They lost their customs and traditions, started to ignore the value of neighborhood. 

Finally, Imams all complained that the youth do not help each other, feel sorry for each other and most 

important of all do not respect each other. 

How can we gain our Lost Values? 

Then Imams were asked what can be done by the religious establishments to overcome this problem 

and they offered some solutions. They suggested that the families should warn their sons and daughters 

for the dangerous results of behaving irresponsible and should mention the beauties of our religion to 

their children. The religious education should be continuous and regular in schools. The religious 

establishments should organize seminars, conferences, workshops to inform our society about the 

beauties and the requirements of our religion. Coffee hours can be organized in religious 

establishments and parents should be invited to discuss the problems of youth within a cooperative 

atmosphere. TV programs, magazines and newspapers can spend more time and space for the religious 

issues by highlighting the negative results of behaving inappropriately such as too many deaths in car 

accidents caused by alcohol. 

The Percentage of People who attend the Mosques 

Imams were asked whether they have realized any increase or decrease within the number of people 

who attend their mosques in the recent years and if yes they were asked to make comments on the 

reasons behind this. The data indicates that the majority of Imams pointed out an increase within the 

number of people who attend their mosques in the recent years and the reason behind this is given as 

the increase in the number of workers from Turkey who come to work in construction companies and 

the number of university students from Turkey and Arabic countries who are all Muslims. Imams 

believe that although the students who come here to study in universities are economically satisfied, 

they feel a spiritual hunger. There is a very beneficial dialogue especially between our young Imams 

and students. Due to the increase in evil, some people started to find hope from God. Imams feel that 

they have got very strong relationships with those who attend their mosques. One final reason given by 

Imams was the opening of border gate to South Cyprus. Imams predicted that, observing Greeks who 

are more devoted to their religion, affected our people in a positive way. 

However, the rest of the Imams claimed a decrease within the number of people who attend 

their mosque in the recent years and they predicted the richness of people as a reason behind this 

decrease. According to Imams, the richer the people are, the more away from religious establishments. 

So the increase in economical growth is seen as a factor for a decrease in religious values. According to 

the descriptive statistics:


Our mosques capacity : 30.000.000 

The number of people who visit these mosques regularly:1500 

The percentage of occupied mosques: 5 % 

As it can be seen from the table, the interest in attending mosques is very low in TRNC. 

Considering the capacities, the mosques are almost empty. The same statistics reveal the times when 

the mosques are most crowded. Imams were given the alternatives as Friday, bairam, daily, Ramadan, 

and special and were asked to put numbers next to each alternative grading 1 as the most crowded and 

5 as the least crowded. 

Statistics 

FRIDAY DAILY BAYRAM RAMADAN SPECIAL 

N Valid 117 89 121 115 111 

Missing 15 43 11 17 21 

Mean 2,75 4,75 1,11 2,89 3,12 

Bairams are the busiest times for mosques. After Bairams, Ramadan month is a very important 

reason for praying. Then comes the Friday prayers. After that, Muslims attend to mosques on special 

nights such as “kandil” nights and finally the least interest demonstrated in the data is for daily prayers. 

Following pie chart demonstrates the nationalities of people who attend to mosques. As it is 

shown, the ratio of Turkish people who attend to mosque is more than the Cypriots. 

Missing 

All 

NATIOANALITY 

Turkish 

Cypriot 

The pie chart below illustrates the case that older people visit mosques more than the younger 

people. 

Other


Missing 

both 

AGE 

old 

young 

The following pie chart represents the eco status of people who attend to mosques, and as it can 

be seen from the chart, poor people are more interested in fulfilling their religious requirements in 

comparison with the rich people. This was also indicated by the written data. Imams wrote that the 

more rich people are, the more away from religious establishments. 

Missing 

ECOSTATUS 

Poor 

Rich 

both


The last pie chart below reveals the literacy level of people who attend to mosques and the chart 

demonstrates that the majority of people who attend to mosques are educated. Only a small ratio is 

uneducated, who don’t know how to read and write. The written data of Imams reveal that the major 

participants of their mosques are students from Turkey and Arabic countries as well as workers from 

Turkey. 

Missing 

4 

LITRERACY 

Literate 

illiterate 

Religious Education in the Past 

When Imams were asked how religious education was in past, almost all confirmed that it was much 

better and more effective. In primary and secondary schools, teachers used to take their students to 

mosques and inform them about their religious requirements there. In summer holidays, there were 

religious courses and Koran courses offered by Imams and parents used to send their children to these 

courses. All teachers used to give more emphasis to religious lessons. The teachers who used to offer 

religious courses in past were more serious and more effective as they used to try their best to make 

children really love religion. 

Only a few Imams feel that religious education is better now by claiming that it used to 

emphasize only a set of rules in past and students used to memorize everything. In past this education 

was one sided, there was no communication, no interaction between the teachers and the students. 

Students used to afraid of their teachers. However now students can question everything and 

accordingly understand more. 

Suggestions for Improving Religious Education 

Then Imams made a lot of suggestions to improve the religious education of students at schools now. 

These include: 

• The weekly hours for religion courses should increase. Now it is 40 minutes a week, however it 

should increase at least to 3 hours a week. 

• Information given in class should be followed by practice. Students should be taken to mosques 

and should practice how to pray which is one of the most important requirements of Islam. 

both


• In each school a room can be converted into a praying room where students can practice praying 

there. 

• It should be a must to take pedagogy courses for the teachers who offer religion courses to be able 

to make students love religion. It would be perfect if Imams themselves study pedagogy and offer 

these courses. 

• The credit of religion courses should be increased. Religion courses should be a must course like 

mathematics course and like mathematics and Turkish courses, a high grade should be required to 

pass religion courses. 

• The books studied at school are very useful as the authors are professors from Turkey who studied 

religious issues in depth. However, the religion teachers do not show any attempt to cover all the 

topics in detail and skip a lot of important issues. Those topics which are studied in class are 

covered in a very surface 

• level without going into details. This method should change. 

• In summers or at the weekends, special religion courses should be held with the permission and 

cooperation of the government and children should be sent to these courses. In this way, we may 

have youth who both give importance to their government and to their religion. 

• If girls and boys study separately, our religion will be affected in a very positive way and things 

will be better in many ways. 

• Opening religious schools should not be banned. 

Suggestions made for Families to improve Religious Education 

Imams then provided insights for what families do to improve the religious education of their children. 

• Firstly Imams all agreed that the young parents themselves first should be given training on 

growing well behaved, decent children first by attending to seminars, conferences and discussion 

groups which need to be supported by government officials. 

• Families should work cooperatively with the religious establishments to be able to help their 

children grow in a morally acceptable ways. 

• According to Imams, the best school is home and the best teachers are the parents so after getting 

enough experience and knowledge on our religion, the parents should inspire their children about 

the beauties of Islam and the importance of behaving in a decent manner. 

• Families can also hire private religion teachers for their children at an early age. 

• It is also suggested that families should encourage their children for drinking a cup of tea once a 

week with Imams, retired elders in mosques to chat on certain topics in a supportive atmosphere. 

This would be highly effective to guide the youth to a desirable direction. 

The Effect of European Union on Religious Values 

Imams were asked to comment on what will happen to our religious values if we join to European 

Union. Data indicate that a sizeable majority of Imams believe that our religious values will be affected 

positively if we join to European Union. They claim that the quality in religion education will increase 

because in order to be able to explain our religion to foreigners, we will definitely feel the need to 

study our religion in detail. As there will be continuous contact with Christians, our people will master 

their religion more. On seeing that Christians are more devoted to their religion, our society will start 

to realize the values they lost. A few Imams gave Turks living in Germany as an example at this point. 

They discussed that Turks living in Germany together with European people are more religious than 

Turks living in Turkish Republic of Northern Cyprus or Turkey because of observing the importance 

foreigners show to their religion. One Imam said we will be more free, so we will be able to wear 

whatever we want. If the girls who are studying in the universities here want to cover their faces, they


will be free to do so. The university won’t be able to forbid such girls’ entrance to classes after joining 

to European Union. 

On the other hand, there were some very pessimistic Imams who thought that our religious 

values will be affected negatively if we join to European Union. Those Imams suggested that the youth 

have already lost their religious values so they might even become Christians when we join to 

European Union. Apart from these, there were also some Imams who did not make any contributions 

for this question and just wrote “time will show us everything”… 

The Effect of European Union on Educational Values 

Another question directed to Imams was what will happen to our educational values if we join to 

European Union. The interpretation of the data reveals that the majority of Imams believe that our 

educational values will be affected positively if we join to European Union. They suggested that the 

quality of education will increase because we will be able to integrate technology into education more, 

we will have more observations, experiences, more chances for improving our science and research 

skills. The education standards will be higher like in European countries and new horizons will be 

opened for our people. After observing how intellectual the Europeans are, Muslim people will be 

more motivated towards education. They will be more motivated to learn foreign languages, especially 

English to be able to communicate with the people around them. The education will be more serious. 

One Imam said that Europeans learned science from our ancestors in past but we as a Muslim society 

could not improve ourselves within years whereas the Europeans did. The same Imam added that when 

Galileo said the world is turning around its axis, this was already indicated within our holy book 1450 

years before Galileo. According to verse Neml 85 in Koran, it says: “Although you think that 

mountains do not move, like the clouds they move continuously”. This verse implies that the world is 

turning continuously. Our prophet Muhammad also encouraged us to study science. During the war, 

Muhammad said that “if a prisoner of war teaches how to read and write to a Muslim, that prisoner of 

war will be free” and he implemented what he said. A hadith interpreted by Tirmizi says that science is 

the lost possession of the Muslim, so wherever he/she finds science, he/she should take that back”. 

These also show the importance given to education and science by our religion. 

Only a few Imams feel that our educational values will be affected negatively if we join to 

European Union claiming that European Union will prevent us from studying our own culture, history 

and religion. Rather we might start to study European cultural studies if we join to European Union. 

Discussion 

To start with, the data reveals that Imams value education a lot. Education is not seen as a factor for 

loosing religious values. Imams have written too many comments to highlight the importance of 

education for a person. Their reaction to the question “Do you think university and above education is 

causing people to move away from religion” is a very supportive indication of this. Some Imams wrote 

“this is a very stupid questionnaire, it is obvious that whoever prepared this questionnaire is not 

definitely aware of Islam and Koran” ☺I am not taking this too personal. Most of them repeated that 

the first requirement of our prophet Mohammad was to “read”. Majority of Imams themselves are 

young and educated from religious schools such as “Imam Hatip” and “Theology Faculty”. This might 

be another reason why they value education too much. Before conducting this research, I was thinking 

that all Imams are about 40 and 50 years old, but I found out that there are a lot of very young Imams 

at about 27-30 years old. 

From all Imams’ perspectives, the value given to education is not enough on the island. For 

them, we are not technologically developed due to our ignorance. One Imam pointed out that according 

to a research he read recently, each Japanese reads approximately 70 books a year and each American 

reads about 60 books a year whereas each Turk reads about 4 books a year. He concludes that this


example proves our ignorance as a society. For sure, he has a right in saying this. It is really a shame 

for our society. 

Although education is highly valued by our religious people, when it comes to discuss about 

modernization and globalization processes, only half of the Imams are in favor of these process 

because they are seen as the admirable creations of God. The other half claimed that modernization and 

globalization are diminishing the world because people are imprisoned in their homes sitting all day in 

front of their televisions and computers which is quiet true. Furthermore, they suggested that 

modernization and globalization are increasing the socialization of people and this in turn increase the 

rate of death. The more people social are, the more they drink alcohol. The unacceptability of drinking 

alcohol was a continuously repeated topic in the analysis of data. This is an important issue to be 

considered because according to the research, the majority of the accidents in 2004, are all caused by 

alcohol. 

One other interpretation of the data reveals that clean heart is a priority in Islam but 

worshipping is the best way to reflect this outside. Just as how a body needs water and soap to be 

clean, human soul needs worshipping. However, majority of Imams agree that there is no forcefulness 

in our religion and it is not fair to judge a person regarding his/her worship. 

Regarding the questions on lost values, it was very interesting to read that all Imams agree that 

we are loosing many of our values such as respect, help, love, customs and traditions. They suggested 

that it is possible to gain these values back with the help of the families, religious establishments and 

government. 

One other interpretation of the data reveals that there is an increase within the number of people 

who attend their mosques in the recent years and the reason behind this is given as the increase in the 

number of workers from Turkey who come to work in construction companies and the number of 

university students from Turkey and Arabic countries who are all Muslims. However, still the number 

of people who attend to mosques is too low. Only 5 % of the mosques are occupied by Muslims. 

Imams relate the lack of interest in religion with the lack in religious education. They all agree 

that in past religious education was much better and effective whereas now it is very passive and 

insignificant. Too many suggestions are made to improve the religious education in schools such as 

increasing contact hours, following information by practice, visiting mosques etc. 

Concerning the questions about European Union in which Imams were asked whether European 

Union will affect our religious and educational values, it appears that a sizeable majority of Imams 

perceive European Union as a very positive improvement for our religion and education. We will be 

more religious on observing how Christians adore their religion and we will be more educated as we 

will have more observations, experiences, research chances, new horizons and technological 

improvements. 

Conclusions 

To return to the initial question asking for a link between the educational values and religious values, it 

might be concluded that there is no apparent effect of education on religion. According to Imams, it is 

wrong to say that university and above education cause people to move away from religion because an 

educated person is a person who knows how to think. Islam is a religion which emphasizes the 

importance of science and logic several times in Koran. For this reason, a university graduate can not 

deny Islam which is a logical religion that continuously highlights the importance of science and 

goodness for a person. Our Prophet Mohammad who said that science is endless so should be studied 

from cradle till grave is a very good indication of the importance of science in Islam. God defines 

knowledge as light, ignorance as darkness and education as the end of ignorance. 

One must note that the definition of education from Imams perspectives is a very detailed one. 

It includes learning the Muslim culture, gaining experience on everything, to read and write, studying 

science, to be open to new developments, to follow technology, to love, to respect others, to behave 

appropriately, to have self-confidence and to be a useful society member. One other important thing to


note at this point is that, education, from Imams’ perspectives, doesn’t only include school education 

but teaching students the rationale behind their own existence in this world. Education should not aim 

to improve a person’ life standards in this world but also should prepare a person for afterlife. 

Another conclusion of this research is the lack of interests shown to religious requirements such 

as attending to mosques in the country. According to the statistics and the interpretation of the written 

data, out of 30.000.000 capacity of the mosques mentioned, there are only 1500 Muslims who are 

regularly visiting the mosques. Only 5% of the mosques are occupied by Muslims. The majority of 

people who attend to mosques are Turkish, old, poor and literate according to the conclusions derived 

from the statistics. The Turkish nationality of Imams who responded to the questionnaire of this 

research is a very good confirmation of the importance given to mosques by Turkish rather than 

Cypriots. There were only a few Turkish Cypriot Imams. 

Imams complained several times about the youth who lost many of their values. An Imam 

wrote this: “When a young person enters into a convertible car, he says: take me to my darling Lejla, 

however when the same person enters the coffin, this time he says: take me to my God”. Another 

conclusion is increase in the alcohol consumption of the youth which in turn end up in a decrease in the 

number of accidents and deaths. This is a very important issue and something should be done to make 

youth understand the dangers of alcohol. Seminars, workshops, conferences might be held on the 

dangers of using alcohol and it should be a must for the all students to attend these presentations. 

Imams stressed the importance of religion for a community. It was interesting to see that 

American Dollar was given as an example to support this. The writing on Dollar “In God We Trust” 

shows Americans trust and admiration to God as the reason behind America being a very rich, 

economically powerful country. So belief in God is an important factor for the development of a 

country from Imams’ perspectives. Here, I would like to point out that people sometimes see different 

sides of a coin. Many people use dollar, but I don’t know how many realized the importance of the 

piece of writing on it. 

One other important conclusion derived from this study is the fact that our society members do 

not give importance to reading. However, our religion does. The first verses of Koran requires all 

Muslims to read. The data pointed out that according to a research an Imam read recently, each 

Japanese reads approximately 70 books a year and each American reads about 60 books a year whereas 

each Turk reads about 4 books a year. This proves our ignorance as a society. We are not 

technologically developed due to our ignorance. Again, this is an important issue to be considered. Our 

children should be encouraged to read. The school education can help a lot at this point. For example, 

the instructors can require book summaries from the students. 

Final conclusion of the study is the optimism of Imams towards European Union. When we 

return to initial research questions asking whether there will be any changes in our religious and 

educational values if we join to European Union, Imams said yes. Furthermore, they predicted that if 

we join to European Union, there will be very positive improvements regarding our religion and 

education. More Europeans will come to our island and we will improve our religious values not to be 

a minority on the island. We will be in close contact with Europeans who are more devoted to their 

religion and this in turn will motivate us towards our own religion. Furthermore, Imams predict that 

there will be positive improvements in terms of education as well, because the standards and the 

quality of education will be increased to be parallel with the European standards. This will provide 

more observations, experiences, research chances, new horizons and technological improvements for 

our students. We will wait and see altogether! 

Further research 

Further research might be conducted for this study. First of all, as this study only reveals Imams’ 

perspectives on religion and education, the questionnaire might be given to families and religion 

teachers and a triangulation might be carried out to compare the results. Later, the same questionnaire 

might be conducted in Southern Cyprus with the help of a colleague from there and the results of North


might be compared with the results of South to see the commonalities and differences between the two 

communities living on the same island. 

References 

[1] Atay, T. (1996) Bati’da Bir Naksi Cemaati .Istanbul:Iletisim Yayincilik. 

[2] Berkes, N. (1998). The Development of Secularism in Turkey. London:Hurst and Company. 

[3] Carkoglu, A. & Toprak, B. (2000). Turkiye’de Din, Toplum ve Siyaset. Istanbul:Tesev 

Yayinlari. (p.43) 

[4] Naffisi, R. M. (2003). Reframing Orientalism:Weber and Islam,in Turner,S.B. (ed). 

Islam:Critical Concepts in Sociology.Routledge:London 

[5] Ozturk, N. Y.(1998) Laik Dunyada Islam. Istanbul:Sabah Kitaplari 

[6] Turner, S. B. (2003) Cosmopolitan Virtue, on Religion in a Global Age, in Turner, S.B. (ed). 

Islam:Critical Concepts in Sociology.Routledge:London 

Internet Sources 

[7] Cyprus Information Resource. Religion. http://reference.allrefer.com/country-guidestudy/cyprus/cyprus 

60.html (Oct. 2004) 

[8] Cyprus. www.state.gov/g/drl/rls/irf/2004/35449.htm (Oct. 2004) 

[9] Keyes, Adam. The roles of state and religious instutions in the Turkish education system. 

http://facweb.furman.edu/*jpitts/20-turkish%20education.htm (Oct. 2004) 

[10] Religion. http://www.trncwashdc.org/e 020.html (Oct. 2004) 

[11] The Society. http://countrysides.us/turkey/23.htm (Oct. 2004)


ISSN 1450-216X Vol.14 No.3 (2006), pp. 388-400 



Characterization of a Possible Modification of the Relation 

Rain-Flow in a Climatic Context of Variability: Case of the 

Catchment Area of the N’zi (Bandama) (Côte.D'ivoire) 

Amani Michel Kouassi 

Laboratoire des Sciences et Techniques de l’Eau et de l’Environnement (LSTEE) 

UFR des Sciences de la Terre et des Ressources Minières (STRM) 

Université de Cocody, 22 B.P. 582 Abidjan 22 (Côte d’Ivoire) 

E-mail: michel.a_kouassi@yahoo.fr; kouamani2000@yahoo.fr 

Tél: (225) 07 492 712 

Koffi Fernand Kouame 




Centre Universitaire de Recherche et d’Application de la Télédétection (CURAT) 


Université de Cocody,. 22 BP 801 Abidjan 22, (Côte d’Ivoire) 

Tél: (225) 07 492 712 

Bi Tié Albert Goula 

Laboratoire Géosciences et Environnement 

UFR des Sciences et Gestion de l’Environnement (SGE) 

Université d’Abobo-Adjamé, 02 B.P. 801 Abidjan 02, (Côte d’Ivoire) 

Jean-Emmanuel Paturel 

HydroSciences Montpellier (HSM) - UM2, IRD 

Case MSE - Place Eugène Bataillon - 34095 

Montpellier cedex 5 (France) 

Théophile Lasm 




Tél: (225) 07 492 712 

Jean Biemi 




Centre Universitaire de Recherche et d’Application de la Télédétection (CURAT) 


Université de Cocody,. 22 BP 801 Abidjan 22, (Côte d’Ivoire) 

Tél: (225) 07 492 712

Characterization of a Possible Modification of the Relation Rain-Flow in a Climatic 

Context of Variability: Case of the Catchment Area of the N’zi (Bandama) (Côte.D'ivoire) 389 

Abstract 

Prolonged conditions of pluviometric and hydrometric deficits constitute a reality 

observed on the level of the area catchment of the N’zi since the end of 1960 and the 

beginning of the years 1970. Among the interrogations which this significant variation 

causes, one of them relates to the possible modification of the relation rain-flow. To 

undertake this study, we had recourse to the modeling of the relation rain-flow starting 

from a total conceptual model with the annual step (model in "S") on the catchment area of 

the river N’zi. After identifying breaks and computing pluviometric and hydrometric 

recession, we carried out a chock over slipping periods five (5) years in order to highlight a 

possible tendency in the evolutions of the residues and the fixed parameters. The 

performances of the model show a good reconstitution of the flows of the rivers. This 

model proved to be robust. The results of the study showed that a modification of the 

relation rain-flow seems to have accompanied the hydroclimatic fluctuation undergone by 

the basin. 

Keywords: Hydroclimatic variability, hydrological modeling, water resources, N’zi, Côte 

d’Ivoire 


En raison de ses répercussions sur le milieu naturel et le développement socio-économique, les 

questions de variabilité climatique et leurs implications sur les ressources en eau sont placées depuis 

quelques temps au centre des préoccupations des scientifiques et des décideurs politiques dans le 

monde. Caractériser l’impact de ces fluctuations sur les disponibilités en eau dans l'espace et dans le 

temps deviennent alors indispensables pour proposer des solutions adaptées aux projets de 

développement et à une gestion durable de l’environnement (Ouédraogo et al., 1998; Ouédraogo, 2001; 

Ardoin et al., 2003 ; Paturel et al., 2003 ; Ardoin, 2004; Sighomnou, 2004 ; Le Lay & Galle, 2005). La 

modélisation hydrologique se présente à cet effet comme un moyen puissant qui essaie d’apporter des 

solutions aux problèmes qui se posent à l’homme (Andréassian, 2004 ; Andréassian et al., 2004 ; 

Ardoin et al., 2002 ; Kouamé et al., 1995 ; Paturel et al., 2003 ; Sigha-N’kamdjou et al., 2002 ; 

Varado, 2004). 

Cette étude propose de caractériser une éventuelle modification de la relation pluie-débit dans 

un contexte de variabilité climatique et de modification de l’occupation du sol au travers de la 

modélisation conceptuelle globale dans le bassin versant du N’zi (Bandama). Le test de détection de 

rupture (procédure de segmentation de Hubert) a permis d’identifier des ruptures éventuelles au sein 

des séries pluviométriques et hydrométriques. Un modèle conceptuel global au pas de temps annuel 

(modèle en « S ») a été utilisé pour analyser la relation pluie-débit (Javelle, 2000 ; Andréassian, 2002 ; 

Mouelhi, 2003). 

2. Présentation de la zone d’étude 

Le secteur d’étude est le bassin versant du N’zi (figure 1), sous-bassin du bassin versant du fleuve 

Bandama. Il prend sa source au Nord de la Côte d’Ivoire dans la région de Ferkéssedougou à une 

altitude de 400 m. Le N’zi coule globalement dans une direction Nord-Sud. La courbe de hauteur d’eau 

du N’zi a une pente moyenne relativement constante de l’ordre de 0,53‰. La densité du réseau 

hydrographique diminue du Sud au Nord. L’affluent principal du N’zi est le Kan qu’il reçoit à environ 

5 km en aval de Dimbokro. Il est compris entre les longitudes 3°49’ et 5°22’ Ouest et les latitudes 6° et 

9°26‘ Nord. Le bassin a une superficie de 35 500 km 2 . De par sa configuration géographique allongée,

390 Amani Michel Kouassi, Koffi Fernand Kouame, Bi Tié Albert Goula, 


4° et 5° de longitude ouest et 6° et 9°25’ de latitude nord, le bassin versant du N’zi est représentatif des 

grands ensembles climatiques de la Côte d’Ivoire. 

Au Nord, règne le régime tropical de transition (climat soudano-guinéen). Le régime tropical 

humide (climat baouléen) est caractéristique de la partie centrale du bassin. Le Sud du bassin se 

caractérise par un régime subéquatorial (climat attiéen) (figure 1). Le bassin du N’zi se caractérise par 

une végétation savanicole dans le centre et le Nord, et une végétation de forêt dans le Sud. Le relief du 

bassin est peu accidenté. Il est généralement constitué de plateaux (100 m à 400 m en moyenne). Cette 

monotonie est rompue par la chaîne Baoulé. Les principaux types de sol sont les sols ferralitiques 

moyennement dessaturés (Nord) et les sols ferralitiques fortement dessaturés (centre et Sud). 

3. Données et méthodes 

La méthodologie a consisté à mettre en évidence la variabilité climatique et hydrologique et analyser 

son impact sur la relation pluie-débit au travers de la modélisation conceptuelle globale. 

3.1. données 

La constitution d’un vecteur régional a permis de reconstituer les données manquantes au sein des 

différentes séries pluviométriques annuelles (Dabakala, Bouaké, Dimbokro et Tiassalé) (figure 1). Les 

séries chronologiques harmonisées s’étendent sur la période 1923-2004. Le choix de ces postes a été 

dicté par la nécessité de disposer de données continues sur une longue période. L’ensemble de ces 

données pluviométriques a été mis à notre disposition par la société de météorologie nationale 

(SODEXAM : Société de Développement et d’Exploitation Aéronautique, Aéroportuaire et 

Météorologique). 

Les données hydrométriques ont été fournies par la Direction de l’Hydraulique Humaine 

(DHH), Sous-direction de l’Hydrologie. Des régressions linéaires entre les débits des stations voisines 

ont permis de combler les valeurs manquantes et d’homogénéiser la durée d’étude sur la période 1951 

à 2000. Les stations étudiées sont M’bahiakro, Bocanda, Dimbokro et N’zianoa (figure 1). Les données 

d’ETP utilisées ont été estimées à l’aide de la méthode de Thornthwaite.



Figure 1: Présentation du bassin versant du N’zi (Bandama) 

3.2. Méthodes d’étude de la variabilité hydroclimatique 

La procédure de segmentation de Hubert et la méthode d’évaluation des déficits par rapport aux 

ruptures identifiées par le test, ont été utilisées pour caractériser et identifier la variabilité 

hydroclimatique. 

3.2.1. Procédure de segmentation de Hubert 

La procédure de segmentation fournit au moyen d'un algorithme spécifique une ou plusieurs dates de 

ruptures (éventuellement aucune) qui séparent des segments contigus dont les moyennes sont 

significativement différentes. La segmentation est retenue lorsque l’écart quadratique entre elle et la 

série est minimum. Cette condition est nécessaire mais non suffisante pour la détermination de la 

segmentation optimale. On défini : ik , k=1, 2,…, m, le rang dans la série initiale de l'extrémité 

terminale du k ième segment X k la moyenne du k ième segment, Dm l'écart quadratique entre la série et 

la segmentation considérée,



avec 

Dm = 

k = m 

∑ d k 

k = 1 

(E 4) 

2 

∑ ( ) 

1 

= 

d k = 

i ik 

Xi 

− XK 

(dk doit être minimum) (E 5) 

i i − 

= k −1 

Cette méthode présente l’avantage de pouvoir rechercher des changements multiples de 

moyenne dans une série hydrométéorologique contrairement à celle de Pettitt. Elle a été utilisée dans 

plusieurs études de changements hydroclimatiques notamment en Afrique de l’Ouest (Servat et al., 

1998 ; Paturel et al., 1998 ; Lubès-Niel et al., 1998). Il est difficile d’attribuer un niveau de 

signification à ce test (Hubert et al., 1989). 

3.2.2. Détermination du déficit hydroclimatique 

Le déficit hydroclimatique par rapport aux ruptures identifiées par le test de rupture a été évalué à 

partir de la formule suivante (Ouédraogo, 2001; Ardoin, 2004): 

x j 

D = − 1 

(E6) 

x i 

avec : 

D : déficit hydroclimatique; 

x j : moyenne de la série après rupture ; 

x i : moyenne de la série avant rupture ; 

Dans le cas où aucune rupture n'est détectée par le test de rupture, le déficit a été calculé en 

prenant l'année 1970 comme année de rupture. 

3.3. Modélisation hydrologique 

3.3.1. Concept du modèle 

Le modèle en « S » conçu par Mouelhi (2003), a été utilisé pour mener cette étude. C’est un modèle 

conceptuel global au pas de temps annuel. Il permet de simuler le débit à l’exutoire d’un bassin versant 

à partir des données de pluie et d’ETP moyenne. Toutes ces données sont exprimées en lame d’eau 

(mm). Le modèle a été conçu par Mouelhi (2003). La base mathématique du modèle se présente 

comme suit: 

P 

Q = n= 

4 

(E7) 

aE i 

∑ ( ) 

i= 

0 P 

avec : 

Q : lame d’eau annuelle ruisselée (mm), 

P : lame d’eau précipitée annuelle (mm), 

E : lame d’eau évapotranspirée annuelle (mm), 

Ce modèle est caractérisé par un seul paramètre libre « a » qui est un coefficient correctif de 

l’évapotranspiration potentielle (ETP). Ses valeurs numériques sont obtenues après optimisation, 

calage et validation. En effet, un seul paramètre libre représenté par « a », semble suffisant pour le pas 

de temps annuel (Perrin et al., 2001, 2003 ; Mouelhi, 2003 ; Mouelhi et al., 2006). Bien que ce modèle 

paraisse simple au point de vue formulation hydrologique du cycle de l’eau, sa performance est assez 

satisfaisante (Mouelhi, 2003). Ce modèle a été testé avec succès sur plus de 429 bassins dans le monde 

dont une dizaine en Côte d’Ivoire (Mouelhi, 2003).



3.3.2. Fonction objectif : critère de Nash 

Le critère d’optimisation utilisé est la somme du carré des écarts entre les débits observés et ceux 

générés par le modèle (critère de Nash) (Mouelhi, 2003 ; Perrin, 2000). Ce critère adimensionnel 

permet de juger de la qualité de l'ajustement et faciliter la comparaison des ajustements sur différents 

bassins dont les écoulements correspondent à des ordres de grandeur différents. Il est défini comme 

suit: 

i i 2 

⎡ ∑( 

Q0−Q ) ⎤ c 

i 

Nash = 100 

⎢ 

1− 

⎥ 

(E 8) 

⎢ i i 2 

( Q0−Qm) ⎥ 

⎢ ∑ 

⎣ i ⎥⎦ 

avec : 

i 

Q : les débits mensuels observés ; 

0 

i 

Q c : les débits mensuels calculés ; 

i 

Q m le débit moyen observé sur l'ensemble de la période d'observation sans lacune. 

Le modèle est considéré comme performant quand les débits estimés se rapprochent des débits 

observés, c’est-à-dire quand la valeur du critère de Nash est proche de 100. Un critère de moins de 

60% ne donne pas une concordance satisfaisante entre les hydrogrammes observés et simulés par le 

modèle. 

3.3.3. Procédure d’étude de la relation pluie-débit 

Elle a consisté à faire des calages sur des périodes glissantes de cinq (5) ans afin de mettre en évidence 

une éventuelle tendance dans l’évolution des résidus de simulation et du paramètre « a » calé. 

4. Résultats et discussion 

4.1. Variabilité des régimes hydroclimatiques 

4.1.1. Variabilité climatique 

En se basant sur l’étude des séries, il est possible de situer la période actuelle de pluviométrie 

déficitaire dans une perspective historique afin de mieux percevoir ainsi l’importance réelle de cette 

évolution climatique récente. Cette analyse est basée sur la période de 1923 à 2004. Sur l’ensemble de 

cette période et pour chacun des postes étudiés, les résultats de l’application de la procédure de 

segmentation de Hubert et de la méthode de calcul des déficits pluviométriques sont consignés dans le 

tableau I. 

Tableau I: Années de rupture et déficits pluviométriques (1923-2004) 

Stations Test de Pettitt Année de rupture Procédure de Segmentation Déficit pluviométrique (%) 

Dabakala 1968 1968 ; 1983 24 

Bouaké 1972 1972 14 

Dimbokro 1968 1938 14 

Tiassalé 1969 Pas de rupture 13 

Ces résultats (procédure de segmentation de Hubert) ont permis de confirmer la baisse globale 

des précipitations autour des années 1970. Toutefois, les résultats diffèrent sur autres stations et 

révèlent en cela l’hétérogénéïté de la variabilité climatique qu’a connu ce bassin ces 80 dernières 

années (tableau I). Par rapport à la période de référence 1923-2004, la méthode de segmentation de 

Hubert a mis en évidence : 

• une reprise globale des précipitations en 1938 au poste de Dimbokro, 

• une amplification en 1983 de la baisse des précipitations au poste de Dabakala.



Les déficits pluviométriques calculés sur la période 1923-2004 fluctuent entre 13% et 24% 

(tableau I) avec une moyenne de 16%. Les déficits les plus élevés sont enregistrés dans le Nord du 

bassin qui correspond à la zone à climat soudanien. En dessous de cette zone, les déficits diminuent 

mais gardent d'une manière générale des proportions variant autour de 14%. Les pourcentages de 

déficits les plus faibles ont été enregistré au Sud du bassin, qui est soumis à un climat à tendance 

équatoriale. Ces résultats montrent que les récessions pluviométriques subies par le bassin, ont été plus 

importantes dans le Nord que toute autre partie du bassin versant. 

Cette variabilité climatique se situe dans un contexte local (Brou, 1997 ; Brou et al., 1998 ; 

Bigot et al., 2005) et régional (Paturel et al., 1998 ; Servat et al., 1998 ; Ouédraogo, 2001 ; Ardoin, 

2004). Du point de vue de la ressource en eau et de son utilisation, il est évident que de telles 

modifications ne sont pas sans conséquences (Savané et al., 2001 ; Brou, 2005 ; Goula et al., 2005 ; 

Sultan et al., 2005). 

4.1.2. Variabilité hydrologique 

Les résultats de l’application de la procédure de segmentation de Hubert montrent que l’ensemble des 

séries des débits annuels analysés présente des ruptures synchrones en 1968. Ces ruptures décelées 

correspondent à une baisse significative des débits moyens annuels. Le caractère synchrone des 

ruptures identifiées au sein des séries chronologiques de pluies et de débit souligne le lien indiscutable 

qui existe entre la baisse de la pluviométrie et la diminution des écoulements de surface sur le bassin 

versant du N’zi. 

Les déficits d’écoulement calculés par rapport aux différentes ruptures (1968) donnent 51% aux 

stations de N’zianoa et Dimbokro, 52% à la station de Bocanda et 55% à la station de M’bahiakro. Les 

déficits d'écoulement sont bien supérieurs à ceux des précipitations. La sécheresse hydrologique est 

plus importante que la sécheresse météorologique. L’effet durable et amplifié des déficits 

pluviométriques sur les écoulements est dû à un appauvrissement des écoulements essentiellement lié à 

celui des aquifères alimentant l’écoulement de base (Mahé et al., 2002, 2005b). 

Parmi les interrogations que suscite cette importante variation hydroclimatique, l’une d’elles 

concerne l’éventuelle modification de la relation pluie-débit. 

4.2. Caractérisation de l’impact de la variabilité hydroclimatique sur la relation pluie-débit 

Les caractéristiques statistiques des résultats de l’application de la procédure du multi-calage au bassin 

principal du N’zi à N’zianoa sont consignées dans le tableau II. 

Tableau II: Caractéristiques statistiques du paramètre « a » et des performances du modèle en « S » au niveau 

du bassin du N’zi à N’zianoa 

Bassins Paramètre a Nash en calage (%) 

Moyenne 1,2 72 

Ecart-type 0,1 28 

Minimum 1,1 4 

Maximum 1,3 98 

Coefficient de variation 0,1 0,4 

Si l’on considère le modèle, une fois calibré, comme un bassin de contrôle c’est-à-dire un 

bassin au comportement stationnaire, la qualité des simulations de ce modèle déclinera au fur et à 

mesure de l’évolution du bassin. La tendance observée sur les résidus permet de caractériser cette 

évolution. En effet, les performances en terme de critère de Nash sont l’image de l’adéquation du 

modèle et du jeu de paramètres calés au bassin étudié (Makhlouf et al., 1992 ; Makhlouf, 1994). 

L’observation de la courbe d’évolution des résidus de simulation (figure 2) montre d’abord une baisse 

sensible de ceux-ci au cours de la période 1969-1973. Cette dégradation des résidus s’est poursuivie



jusqu’en 1980. Enfin, une chute brutale des résidus à été également observée au cours de la période 

1991-1995. Ces périodes de dégradations identifiées correspondent aux grandes périodes sèches 

observées au niveau du bassin principal du N’zi. Ces résultats montrent que des changements 

importants ont pu affecter le bassin du N’zi de façon générale qui seraient non contenus dans les 

données débimétriques et pluviométriques et évaporatives mais dans les caractéristiques lithologiques, 

la végétation et d’autres paramètres physiques du bassin (Le Lay, 2006). 

Figure 2 : Résidus de simulation sur la période 1961-1997 quantifiés par le critère de Nash (modèle en « S ») 

au niveau du bassin du N’zi à N’zianoa 

Nash (%) 

150 

100 

50 

0 

-50 

-100 

-150 

1961-1965 

1963-1967 

1965-1969 

1967-1971 

1969-1973 

1971-1975 

1973-1977 

1975-1979 

1977-1981 

1979-1983 

1981-1985 

1983-1987 

1985-1989 

1987-1991 

1989-1993 

1991-1995 

1993-1997 

Périodes de calage 

Chercher la trace de changements hydrologiques dans les valeurs de paramètres suppose une 

hypothèse forte, qui est la signification de ces valeurs lorsqu’elles sont considérées individuellement. 

Les variations des valeurs du paramètre de calage « a » autour de la moyenne sont de moins de 10% 

(tableau II et figure 3). Ces résultats mettent en évidence une fluctuation du paramètre de calage. La 

variabilité du paramètre peut paraître surprenante dans la mesure où ils décrivent des caractéristiques 

du bassin censées être indépendants des conditions de calage. Il semble donc que les variations des 

paramètres traduisent les changements observés dans la relation pluie-débit si l’on se confère à 

l’hypothèse de Lubès-Niel et al. (2003) cités par Le Lay (2006) selon laquelle « la stabilité des valeurs 

de paramètres traduit une stabilité hydrologique ».



Figure 3: Evolution du paramètre « a » en fonction des périodes de calage au niveau du bassin du N’zi à 

N’zianoa (1961-1997) 

Paramètre de calage 

1961-1965 

1963-1967 

1965-1969 

1967-1971 

1969-1973 

1971-1975 

1973-1977 

1975-1979 

1977-1981 

1979-1983 

1981-1985 

1983-1987 

1985-1989 

1987-1991 

1989-1993 

1991-1995 

1993-1997 

1,5 

1,4 

1,3 

1,2 

1,1 

1 

0,9 

0,8 

4.3. Discussion des résultats 

Intervalle de confiance 

Paramètre a 

Périodes de calage 

Une analyse des résultats acquis montre qu’un certain nombre de facteurs abordés antérieurement ou 

non peuvent expliquer l’évolution observée. La variabilité pluviométrique, caractérisée par une 

diminution de la quantité et de la fréquence des hauteurs de pluie, la modification saisonnière de la 

distribution des précipitations sont les causes probables des changements dans la réponse du bassin. 

Cette variabilité pluviométrique s’accompagne aussi d’une diminution du nombre de systèmes 

convectifs de méso-échelle (Le Lay, 2006). En effet, l’intermittence des pluies joue un rôle important 

dans la genèse du ruissellement. Aussi, de plus en plus, l’essentiel des précipitations se retrouve-t-il 

sous forme d’évapotranspiration conséquence de la hausse des températures ce qui pourrait expliquer 

en partie l’évolution de la relation pluie-débit. Une baisse des volumes d’eau mobilisés par les nappes 

d’eau souterraines conséquence de la diminution prolongée de la pluviométrie ne saurait ne pas être 

avancer pour expliquer cette variabilité constatée dans la relation pluie-débit. En effet, la diminution 

des coefficients d’écoulement observé dans de nombreux bassins en Afrique de l’Ouest peut 

s’expliquer, selon Mahé et al. (2003, 2005b), par une diminution des ressources en eaux souterraines. 

Ce qui se traduit par une baisse du niveau moyen des nappes et une diminution de leur soutien aux 

étiages, résultats qui confirment ceux obtenus au niveau du bassin versant du N’zi. La modification de 

l’occupation du sol, conséquence éventuelle de la variabilité pluviométrique et de la forte 

anthropisation du bassin, peut être avancer comme facteur de l’évolution de la relation pluie-débit 

(Andréassian, 2002). Sous la pression démographique croissante et la nécessité de développement 

économique, l’occupation du sol a été très modifiée au niveau du bassin versant du N’zi (Brou, 2005). 

Le bassin se caractérise donc par une forte diminution des surfaces boisées et une importante 

augmentation des terres destinées aux cultures et pâturages. En effet, la couverture végétale et la mise 

en culture sont les principaux facteurs explicatifs de la variabilité du ruissellement. Or cette couverture 

végétale est susceptible de fortes variations sous l’effet des feux de brousse et de la sénescence 

périodique.



5. Conclusion 

Cette étude a permis de caractériser les principales manifestations de la variabilité climatique et 

hydrologique observée depuis plus de trois décennies au niveau de la région tropicale humide de 

l’Afrique de l’Ouest en général et en particulier dans la région du bassin versant du N’zi (Bandama) en 

Côte d’Ivoire. Sur l’ensemble du bassin, des conditions prolongées de déficits pluviométriques et 

hydrométriques depuis les années 1970 ont été mises en évidence. Cette sécheresse s’est amplifiée 

pendant les années 1980. Si l’amplitude du phénomène, apparu aux alentours des années 1970, n’est 

pas uniforme, toutes les régions (Nord, centre et Sud) ont cependant été touchées. 

Les régimes hydrologiques ont également subi de profondes modifications. En effet, la baisse 

de la pluviométrie a eu pour effet de diminuer les apports d’eau qui transitent dans les cours d’eau du 

bassin. Ainsi, depuis les années 1970, un effondrement des débits des cours d’eau est observé. Cette 

diminution est marquée par une rupture identifiée en 1968 sur l’ensemble des stations. Les volumes 

écoulés ont diminué et cette baisse atteint en moyenne 52% et atteint par endroit 55%. L'incidence du 

déficit pluviométrique observé est manifeste sur la disponibilité des ressources en eau. Les irrégularités 

des précipitations se traduisent par des fluctuations plus importantes au niveau des écoulements. La 

sécheresse météorologique se trouve ainsi amplifiée dans les écoulements. 

Le modèle conceptuel global au pas de temps annuel « S », a d’abord montré sa capacité à 

simuler les écoulements dans un contexte de variabilité climatique et de modification de l’occupation 

du sol, conséquences des activités anthropiques. Il a permis de mettre en évidence une modification de 

la relation pluie-débit au niveau du bassin versant du N’zi au cours de ces dernières décennies (1970- 

2000).



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Université de Yaoundé 1, Cameroun. 279pp. 

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Polytechnique de Grénoble, France. 278pp.


ISSN 1450-216X Vol.14 No.3 (2006), pp. 401-406 



Seedling Growth of Gmelina Arborea (Roxb) as Influenced by 

Crude Oil in Soil 

Agbogidi, O. M 

Department of Forestry and Wildlife, Faculty of Agriculture 

Delta State University, Asaba Campus, Delta State,Nigeria 

E-mail: omagbogidi@yahoo.com 

Dolor, D. E 



Okechukwu, E. M 



Abstract 

A study was carried out in 2005 on the seedling growth of Gmelina arborea as 

influenced by crude oil in soil in Asaba, Delta State, Nigeria. The experiment was laid out 

in a randomized complete block design with four treatments (0% (control), 4%, 8% and 

12% wet weight (w/w) of crude oil) and replicated four times. Parameters measured at 

different growth stages (1, 2 and 3 months after transplanting) were plant height, number of 

leaves, leaf area, collar girth and dry weight biomass per seedling per treatment. The results 

showed significant reductions (P=0.0.5) in all the growth characters assessed throughout 

the experimental period in seedlings subjected to crude oil treatment when compared with 

those grown in the uncontaminated soils. The height, number of leaves, leaf area and collar 

girth of seedlings exposed to 12% oil treatment was 29. 6 cm, 6.3, 50.2 cm 2 and 1.0 cm 

while those in the control soils were 49.4 cm, 17.8, 109.3 cm 2 and 2.2 cm at 2 months after 

transplanting respectively. This study has demonstrated that crude oil contaminated soil 

significantly reduced the performance of Gmelina seedlings. The present study indicated 

that G. arborea could be tested for phyto – remediation studies in crude oil contaminated 

areas. 

Key words: Crude oil, soil contamination, seedling growth, Gmelina arborea. 

Introduction 

Gmelina, Gmelina arborea, a fast growing exotic tree species was first introduced to Nigeria in 1924 

(Akoun et al., 2002). It is a fuel wood and a chew stick species. Goat and sheep relish G.arborea 

greatly (Etukudo, 2000). With the current high cost of building materials, many people are using 

wattles as support in wattle – and - daub houses and G. arborea is a popular species in this direction. In 

the rain forest and derived savanna zones, G. arborea is recommended for use in our farms to supply 

nitrogen to the soil (Etukudo, 2000). He maintained that G. arborea is among the trees recommended

Seedling Growth of Gmelina Arborea (Roxb) as Influenced by Crude Oil in Soil 402 

for quick vegetal cover of erosion sites. The tree is also readily used in taungya or agrisilviculture 

systems. G. arborea is popularly used in addition to the non – nitrogenous indigenous species like 

Anthornatha macrophylla and Dialium guineensis in alley cropping. It is also locally used to demarcate 

boundaries. As a result of it’s use as a timber tree, pulpwood, matchstick, ornamental, fodder, 

fuelwood, bee forage and a shade plant, G. arbores is known to display multipurpose uses (Etukudo, 

2000). 

Severe ecological damage has occurred in the Niger Delta area where most of the oil industrial 

activities are predominant (Agbogidi and Edema, 2003). Oil exploration and exploitation activities 

though, with tremendous economic benefits, have been reported to have serious adverse effects on 

plants and the environment (Agbogidi et al., 2005a; Ekpo and Nwankpa, 2005; Agbogidi and Ejemete, 

2005; Agbogidi and Eshegbeyi, 2006). With the teaming population of Nigeria and high demand for 

forest species in many endeavours including fuel wood, timber needs and as fodder, it has become 

important to study the effects of crude oil contaminated soil on the seedling growth of Gmelina, which, 

though an exotic species, has displayed multipurpose uses over the years. The objective of this study 

was to investigate the seedling growth of Gmelina arborea as influenced by crude oil in soil. 


The experiment was conducted in Delta State University, Asaba Campus with garden soil mixed with 

various crude oil concentrations (0%, 4%, 8% and 12%) constituting the treatments. The crude oil used 

was sourced from the Nigerian National Petroleum Corporation (NNPC), Warri, Nigeria. The oil had a 

specific gravity of 0.864 gm -3 and API gravity of 38.9. The oil treated and the uncontaminated soils 

were kept in 10 cm / 20 cm bottom – perforated poly pots. The 8 weeks old Gmelina seedlings already 

sown in the departmental nursing were transplanted to the crude oil treated soils and the control soils; a 

seedling per poly pot. The experiment was laid out in a randomized complete block design (RCBD). 

There were therefore four treatments replicated four times. Each treatment comprised 8 poly pots. The 

poly pots were watered to field capacity using watering can immediately after transplanting and 

thereafter, every other day till the end of the trial following the method of Agbogidi and Ejemete 

(2005) and Agbogidi et al. (2006a) and Agbogidi et al.(2006b). The seedlings were allowed to 

establish in the departmental nursery beds. Growth variables were measured for three months starting 

from one month after transplanting (MAT). Parameters assessed were plant height, number of leaves, 

leaf area, collar growth and dry weight biomass. Plant height was determined with a meter rule at the 

distance from soil level to the top of the terminal bud, the number of leaves was determined by visual 

counting of the leaves, leaf area was determined by multiplying the length and breath measurements of 

a leaf multiplied by the number of leaves in the plant and finally by a correction factor of 0.75 

following the procedure of Agbogidi and Ofuoku (2005). Girth growth at 3 cm above soil level was 

determined using veneer calipers. The dry weight biomass was determined after the seedlings were 

harvested at 3 MAT, sorted out into roots, stems and leaves and oven dried at 85ºC for 22 hours 

following the methods of Anon (1966) and Agbogidi et al. (2005b). 

Data collected were subjected to analysis of variance while the significant means were 

separated with the Duncan’s multiple range tests using SAS (1996). 


Significant reductions (P = 0.05) in the Gmelina seedlings were observed in all the parameters assessed 

on monthly intervals with increasing oil level throughout the experimental period when compared with 

seedlings grown in the uncontaminated soils (Tables 1, 2, 3, 4 and 5). The performance of the seedlings 

in terms of height, number of leaves, leaf area, girth growth and dry biomass was poorer as the level of 

oil contamination in soil increased. For example, growth stagnation and stunting were observed for 

seedlings subjected to soils that received 12% oil treatments while the seedlings in the control soil 

grew normally.

403 Agbogidi, O. M, Dolor, D. E and Okechukwu, E. M 

Table 1: Plant height (cm) of G. arborea seedlings as influenced by crude oil in soil 

Oil in soil (%w/w) Plant height / MAT 

1 2 3 

0 37.6a 49.4a 57.8a 

4 35.4b 45.3b 54.5b 

8 32.7c 40.6c 42.4c 

12 27.2d 29.6d 29.6d 

Means in the same column with different superscripts are significantly different at P=0.05 using Duncan’s multiple range 

test. 

Table 2: Number of leaves of G. arborea seedlings as influenced by crude oil in soil 

Oil in soil (%w/w) Number of leaves / MAT 

1 2 3 

0 14.7a 17.8a 21.6a 

4 12.8b 14.5b 16.9b 

8 9.7c 10.9c 11.3c 

12 7.0d 6.3d 5.5d 


test. 

Table 3: Leaf area (cm 2 ) of G. arborea seedlings as influenced by crude oil in soil 

Oil in soil (%w/w) Number of leaves / MAT 

1 2 3 

0 89.6a 109.3a 129.4a 

4 72.4b 93.8b 100.6b 

8 64.5c 71.4c 76.3c 

12 51.8d 50.2d 47.5d 


test. 

Table 4: Collar girth (cm) of G. arborea seedlings as influenced by crude oil in soil 

Oil in soil (%w/w) Collar girth / MAT 

1 2 3 

0 1.9a 2.2a 2.4a 

4 1.6b 1.8b 1.9b 

8 1.4c 1.5c 1.6c 

12 1.0d 1.0d 1.0d 


test.


Table 5: Dry biomass (g) of G. arborea seedlings as influenced by crude oil in soil 

Oil in soil (%w/w) Plant parts 

Roots Stems Leaves 

0 0.9a 1.2a 0.7a 

4 0.7b 0.8b 0.5b 

8 0.4c 5.9c 3.1c 

12 0.2d 0.3d 0.1d 


test. 

The observed reductions in the growth characters of the test plant with increasing oil levels 

could be due to nutrient deficiency in soil that received oil treatment. This could have stemmed from 

nutrient immobilisation. Agbogidi et al. (2005b) and Agbogidi and Ejemete (2005) noted that 

symptoms of oil pollution of soil on plants were typical of extreme nutrient deficiency. This finding is 

in harmony with prior report of Schwendinger (1968) who observed that nutrient deficiency symptoms 

in crude oil affected areas could be indirectly proportional to water uptake, as such, plant damage was 

most probably due to a derangement of the plant- water relations of the roots within the soil. Bamidele 

and Agbogidi (2000) and Bamidele and Agbogidi (2006) also noted that apart from damage the foliage, 

the interference with uptake of water and nutrients as direct biochemical toxicity of hydrocarbons 

could be a serious factor in oil pollution effects. 

Oil contaminated soils were found to depress leaf growth and enlargement hence the observed 

reduced number of leaves and leaf area in seedlings exposed to oil treatment when compared with their 

counterparts grown in the uncontaminated soils. The uptake of toxic substances in the oil including 

heavy metals could have also inhibited growth in the height and development in leaf growth and collar 

girth of seedlings to oil treatment. 

Leaf shedding / leaf drop seedlings exposed to 12% of the oil as from the second month after 

transplanting could have accounted for the observed significant reductions both in the number of leaves 

and leaf area. Leaf shedding could have arisen from inadequate leaf turgidity consequent upon the 

adulterated structure of the soil following crude oil application to soil. The observation supports prior 

report by Agbogidi et al. (2006a). 

Agbogidi and Nweke (2005) and Agbogidi and Eshegbeyi (2006) had reported that crude oil 

application to soil has a damaging effect on leaf initiation and production as well as cell expansion and 

enlargement. Crude oil application to soil could have also caused an obstruction to the xylem and 

phloem vessels of the seedlings thereby inhibiting translocation of both photosynthates and water 

throughout the plant body and subsequently, the observed reduced yield biomass compared to the high 

dry weight yields of seedlings grown in soils without crude oil treatment. Previous investigations by 

Agbogidi and Ofuoku (2005) indicated that yield reduction consequent upon crude oil application to 

soil could have stemmed from an inhibition of photosynthesis due to a decrease in carbon dioxide 

assimilation. Many researchers including Baker (1970) had demonstrated that crude oil consistently 

reduce the rate of photosynthesis through cell injury and disruptions in cell membranes. Yield 

reductions following crude oil treatment have been reported by Udo and Oputa (1984), Anoliefo and 

Vwioko (1994), Jaja and Barber (1999), Agbogidi and Nweke (2005), Agbogidi and Edema (2003), 

Agbogidi and Eshegbeyi (2006) Agbogidi et al. (2006b) and Bamidele and Agbogidi (2006). The 

observed negative relationship between the dry matters yield of the seedlings and the crude oil 

contamination level is not out of place as the seedlings had stopped growing normally consequent upon 

the adulterated structure of the soil following crude oil application to soil.

405 Agbogidi, O. M, Dolor, D. E and Okechukwu, E. M 

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the growth of Panicum repens Linn. Nigerian Journal of Ecology 6:1-4. 

[2] Agbogidi, O.M. and Ejemete, O.R. 2005. An assessment of the effects of crude oil pollution on 

soil properties, germination and growth of Gambaya albida (L.). Uniswa Research Journal of 

Agriculture, Science and Technology 8 (2): 148-155 

[3] Agbogidi, O.M. and Eshegbeyi, O.F. 2006. Performance of Dacryodes edulis (Don. G. Lam 

H.J.) seeds and seedlings in a crude oil contaminated soil. Journal of Sustainable Forestry 22 

(3/4) (In press). 

[4] Agbogidi, O.M. and Nweke, F.U. 2005. Effects of crude oil polluted soil on the performance of 

okra (Abelmoschus esculentus) Moench in Delta State. African Journal of Natural Sciences 8 

(1) (In press). 

[5] Agbogidi, O.M. and Ofuoku, A.U. 2005. Response of sour sop (Annona muricata Linn.) to 

crude oil levels. Journal of Sustainable Tropical Agricultural Research 16:98-102. 

[6] Agbogidi, O.M., Okonta, B.C. and Dolor, D.E. 2005a. Socio-economic and environmental 

impact of crude oil exploration and production on agricultural production: a case study of 

Edjeba and Kokori communities in Delta State of Nigeria. Global Journal of Environmental 

Sciences 4 (2): 171-176. 

[7] Agbogidi, O.M., Nweke, F.U. and Eshegbeyi, O.F. 2005b. Effects of soil pollution by crude oil 

on seedling growth of Leucaena leucocephala (Lam.) de Witt. Global Journal of Agricultural 

Sciences 4 (2) (In press). 

[8] Agbogidi, O.M., Onosode, A. T. and Ofuoku, A .U. 2006a. Impact of crude oil on the 

performance of pararubber, Hevea brasiliensis (Kunth) Muell in Delta State, Nigeria. European 

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[9] Agbogidi, O.M., Onosode, A.T. and Okonta, B.C. 2006b. Susceptibility of Dennettia tripetala 

(Bak.) F. seeds to crude oil. Journal of Food, Agriculture and Environment 4 (2): 350 – 352. 

[10] Akoun, J., Amadi, J., Ijeoma, N., Uche, C. and Ameh, C. 2002. A review of past research 

activities on Gmelina arborea in forestry research institute of Nigeria. In: Abu J.E., Oni, P.I. 

and Popoola, L. (eds.). Proceedings off the 28 th Annual Conference of FAN, held in 

Akure,Ondo State between 4 th and 8 th of November, 2002. Pp 286 – 293. 

[11] Anoliefo, G. and D.E. Vwioko. 1994. Effects of spent lubricating oil on the growth of 

Capsicum annum (L) and Lycopersicon esculentum (Miller). Environmental Pollution 88:361- 

364 

[12] Anonymous 1966. International rules for seed testing association, Norway (ISTA) Seed Service 

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Bulletin, 2003, Lagos, Nigeria 

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[15] Bamidele, J.F. and . Agbogidi, O. M. 2000. Toxicity of odidi petroleum oil and its watersoluble 

fraction on three aquatic macrophytes. Nigerian Journal of Science and Environment 

2:113-121. 

[16] Bamidele, J.F. and. Agbogidi, O.M. 2006. The effects of crude oil on the seedling growth of 

Machaerium lunatus (L) G. F. W. MED. Discovery and Innovation 18(2)(In Press). 

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of ginger (Zingiber officinale) in the tropics. Journal of Sustainable Tropical Agricultural 

Research 16: 67 – 71. 

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Annual Conference of the Nigerian Institute of Food Science and Technology (NIFST) held in 

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plant growth. Journal of Biology and Applied Chemistry 29: 3 – 14.


ISSN 1450-216X Vol.14 No.3 (2006), pp. 407-416 



A Comparative Analysis of Gibberellic Acid Content with 

Respect to Tuber Induction in Potato Plants Grown Under 

Differential Photoperiod and Temperature 

Ahmed Malkawi 

Department of Chemistry and Physics 

Northwest Missouri State University 

Maryville, MO 64468, USA 

E-mail: amalkaw@nwmissouri.edu 

Abstract 

A time-course experiment was performed to determine the effect of photoperiod 

and temperature on endogenous gibberellic acid (GA3) levels in vegetative tissues of potato 

(Solanum tuberosum cultivar “Russet Burbank”) in search of an unequivocal role for GA3 

in tuber induction. Plants were initially grown in tuber non-inducing climatic conditions 

(30ºC day and 26ºC night with an 18-hour photoperiod) until they reached a height of 55 to 

60 cm after which half of the plants were transferred to inducing climatic conditions (24ºC 

day and 12ºC night with a 10-hour photoperiod). Harvest of each plant type began 48 hours 

later and over a period of 10 days with 2-day intervals. Plants were divided into aerial and 

underground tissues, freeze-dried, ground, and then subjected to a purification procedure 

involving solvent extraction and high performance liquid chromatography. The purified 

GA3 extract was then quantified by using combined gas chromatography-mass 

spectrometry. Levels of GA3 declined progressively during the ten-day tuber induction 

period while it slightly increased under non-inducing conditions progressively. Our study 

establishes a strong correlation between decreased GA3 level and tuber induction. 

Keywords: chromatography, gibberellic acid, plant hormone, potato, Solanum tuberosum 

Introduction 

Potato tuberization is the physiological process whereby a stem section of a plant undergoes 

morphological changes to become a special storage organ for reserve food such as carbohydrates and 

proteins (Melis and van Staden 1984; Ewing and Struik 1992). Under optimum environmental 

conditions for potato plants to switch from vegetative development to reproductive growth, a signal 

formed in the leaves is transmitted through the phloem to the underground stems, called stolons 

(Jackson 1999; Suarez-Lopez 2005 Rodriguez-Falcon et al. 2006). The synthesis of such signal and its 

translocation is referred to as the induction of tuberization and signal is known as the “tuberization 

stimulus”. The leaf-derived signal can be transmitted across a graft union, as demonstrated in 

experiments involving ordinary plants (Gregory 1956; Chapman 1958; Kumar and Wareing 1973) as 

well as transgenic plants (Jackson et al. 1998). The induction of tubers is considered a key 

developmental stage in the potato crop’s life cycle, with “profound implications for subsequent growth 

and development” (O’Brian et al. 1998).

A Comparative Analysis of Gibberellic Acid Content with Respect to Tuber 

Induction in Potato Plants Grown Under Differential Photoperiod and Temperature 408 

Tuber induction is controlled by endogenous plant hormones (Melis and van Staden 1984; 

Vreugdenhil and Struik 1989), which are governed by environmental factors, mainly photoperiod and 

temperature. Potato plants integrate day-length measurement with temperature perception to ensure an 

appropriate environmental regulation of tuberization. The length of photoperiod (the relative duration 

of light and darkness during a day), the intensity of incident light, and the temperature requirements 

vary with genotype (Snyder and Ewing 1989; Jackson 1999). Every cultivar requires a threshold 

photoperiod and a critical temperature above which tuberization cannot occur (Ewing and Struik 1992). 

Potato is best grown in temperate climate (Haverkort 1990). In general, short days, high-intensity light 

and cool temperature (referred to as tuber climatic inducing conditions) promote tuberization whereas 

long days, low-intensity light and high temperature (tuber non-inducing climatic conditions) delay or 

inhibit the process (Jackson 1999; Ewing and Struik 1992). 

The tuberization signal initiates cellular changes in the subapical region of the stolon (Xu et al. 

1998b; Jackson 1999; Vreugdenhil et al. 1999; Hannapel 2004) which result in a sink organ for 

carbohydrate and protein accumulation leading to the newly formed potato tuber (Fernie and 

Willmitzer 2001; Hannapel et al 2004). The identity of the tuberization signal is still unknown 

(Rodriguez-Falcon et al. 2006). Such a mobile signal is thought to include positive and negative 

regulators of tuberization (Jackson 1999). The positive regulator is an inducing component formed 

under inducing conditions whereas the negative regulator is an inhibitory component that forms under 

non-inducing conditions. Tuber induction is believed to occur when the ratio of stimulus to inhibitor 

exceeds a certain threshold. 

Physiological and transgenic studies imply gibberellins in an inhibitory functional role, and 

consequently, the inhibitory component of the tuber induction signal is believed to be a gibberellin 

(Jackson et al. 1996; Jackson and Prat 1996; Amador et al. 2001; Martinez-Garcia et al. 2002) 

Gibberellic acid (also known as gibberellin A3 or GA3) is a pentacyclic diterpenoid compound, 

structure shown in Figure 1, and one of more than 126 members of a ubiquitous class of natural 

products called gibberellins (Hedden and Phillips 2000; Mander 1992, 2003). GA3 is a plant hormone 

that elicits profound effects on various phases of plant growth and development (Kende and Zeevart 

1997). 

Figure 1: Molecular structures of the gibberellic acid (left) isolated from S. tuberosum and 7-hydroxycoumarin- 

4-acetic acid (right) used as internal standard in the present analysis. 

HO 

O 

O 

H 

HO 

H 

O 

OH 

HO 

COOH 

O O 

The most common gibberellin used in physiological studies of potato plant growth and 

development is GA3. A central question in the understanding of tuber induction mechanism is the 

extent to which GA3 biosynthesis is limited by environmental conditions while establishing a 

regulatory role proposed for this compound in the tuberization process. Traditionally, investigation of 

this question has been designed to give a qualitative answer by studying the effects of exogenously 

applied GA3 on the morphological development of potato plants. Clearly, a more complete 

understanding of the role of GA3 in tuber induction and development will require quantification of GA3 

profiles in potato tissues grown in certain photothermal regimes. It is difficult to draw conclusions 

from measurements of gibberellin-like activity or total content of GA3 from samples harvested at just a 

single time point. In the present work, we have used a time-course quantitative approach to the 

problem. A detailed time-course experiment was conducted to determine the effect of temperature and

409 Ahmed Malkawi 

photoperiod on the endogenous levels of GA3 in potato plants grown in inducing and non-inducing 

conditions. To our knowledge, time-course determination of endogenous GA3 absolute levels during 

the whole developing tuber induction process has not been reported. 

Knowledge of quantitative changes of GA3 content in potato plants may have important 

implications not only for our understanding of regulation of tuber induction and elucidation of its 

molecular mechanism, but also for the design of effective strategies for yield improvement. 

Materials and Method 

Plant material and growth conditions 

Seed tubers of Solanum tuberosum cv. Russet Burbank were sowed in 0.8-L plastic pots filled with a 

pre-moistened mixture of garden soil and sand (1:1 v/v). This was an appropriate growth medium for 

the plants studied. The plants were grown in a growth chamber under 18 hours of light (at 30ºC) and 6 

hours of darkness (at 26ºC). Temperatures were controlled to ±0.5ºC. Flourescent strip light was used 

during the light period providing a photonsynthetic photon flux of 140 µmol m -2 s -1 at top of plant 

canopies. Tubers were watered daily with tap water and fertilized weekly with 0.1% Miracle-Gro (Port 

Washington, NY). When plants reached approximately 55-60 cm height, half of the 8-week old plants 

were randomly selected and transferred to a second growth chamber adjusted to tuber-inducing 

conditions (24ºC day, 12ºC night and a 10-hour photoperiod). Plant harvest began 2 days later and 

continued for a period of 10 days at 2-day intervals. Each time three samples were randomly selected 

from each chamber, removed from growth medium, washed with distilled water, separated into aerial 

and underground portions, freeze-dried, ground with a mill to a fine powder and stored in glass bottles 

at -20 C until analysis. 

Extraction of gibberellic acid 

One gram of ground tissue sample was mixed with 40 ml of ethyl acetate containing 500.0 ng of 7hydroxycoumarin-4-acetic 

acid, Figure 1, as an internal standard for quantification. The resulting 

mixture was placed in an ultra-sonic bath for 2 hours in ice-cooled water. The solution was vacuum 

filtered and the supernatant was filtered through Nylon-66 filters (0.45 micron). Gibberellic acid was 

separated from the ethyl acetate when the filtrate was partitioned 3 times with 15 ml of 1.0 M NaHCO3 

solution. The combined aqueous extract was adjusted to pH 4.0 with 1.0 M H2SO4. Thereafter, this 

aqueous phase was partitioned 3 times with 15 ml volumes of ethyl acetate. The combined ethyl 

acetate fractions were evaporated to dryness under reduced pressure and the residue was reconstituted 

in 1.0 ml ethanol for subsequent chromatographic analysis. 

Preparative HPLC Analysis 

A Hewlett-Packard HPLC system Model 1090 equipped with a photodiode array detector was used. 

Chromatographic separation was performed with a Spherisorb ODS-2 C18 reversed-phase column (25 

cm long x 4.6 mm i.d.; 5 µm packing; 80 Ao pore size; Waters Corporation, Taunton, MA) and a 

Spherisorb ODS-2 C18 pre-column (7.5 mm x 4.6 mm; 5 µm packing; Alltech, MA). Prior to injection, 

the standard and extract samples were filtered through Nylon Acrodisc syringe filters (13 mm 

diameter, 0.2 micron pore size; Gelman Sciences, MI). All solvents were filtered through MSI Magna 

Nylon membrane filters (Micron Separations, Westboro, MA; 47 mm diameter / 0.45-µm pore size). 

A solvent system of acetonitrile and water (containing 0.1% acetic acid) was used for isocratic 

elution with 80% acetonitrile over 10 minutes and solvent flow rate of 0.9 mL/min. Gibberellic acid 

was detected by UV absorbance at 230 nm. Fractions at the retention time of GA3 (5 minutes) were 

collected and combined and the solvent was evaporated and the residue was re-dissolved in 0.5 ml of 

dichloromethane for subsequent GC-MS analysis.



GC-MS Analysis 

GC-MS was completed with a Hewlett-Packard 5890 gas chromatograph interfaced with a Hewlett- 

Packard 5970 mass selective detector (Hewlett-Packard, Wilmington, DE, USA) working in the 

electron-impact ionization mode at 70 eV and ionization current of 600 µA. Samples were injected 

split-less into a methylsilicone fused-silica capillary column (25 m x 0.25 mm i.d.; 0.25 µm 

methylsilicone film thickness; Quadrex Corporation, New Haven, CT). The carrier gas was helium 

with a flow rate of 2.5 ml/min and the mass spectrometer was operated in the “scan” mode. The 

injection port and detector temperatures were 260ºC and 300ºC, respectively. The column temperature 

was programmed from 120ºC to 220ºC at 15ºC min -1 , then at a rate of 6ºC min -1 to 270ºC with 

isothermal hold at this temperature for 4 minutes. The retention times of GA3 and 7-hydroxycoumarin- 

4-acetic acid were 8 and 6 minutes respectively. Peak identification was based upon mass spectra 

comparison between endogenous and standard compounds. 

Calibration curves 

The instrument calibration standard was first prepared by dissolving 100 mg of GA3 in 1.0 ml CH2Cl2. 

By serial dilution, 1.0-ml stock solutions were then prepared that contained 1/2, 1/4, 1/8, 1/16, 1/32, 

and 1/64 of this concentration. To each of these solutions was added 300 µl of CH2Cl2 containing 

500.0 ng of 7-hydroxycoumarin-4-acetic acid as internal standard solution. The standard solutions 

contained concentrations of GA3 that bracketed the estimated concentrations of GA3 in the potato 

tissue extract after an initial analysis of the potato extracts. Each solution was prepared in triplicate (3 

per day) and over 3 different days to determine both intra-assay and inter-assay precision of retention 

time and peak area of GA3 relative to internal standard. For each solution analyzed, three replicate 

injections into the gas chromatograph were made. The solutions were stored in a refrigerator at 4ºC 

when not in use. The mean peak area of the analyte divided by that of internal standard was plotted 

versus amount of GA3 divided by internal standard amount. The correlation coefficients for these three 

standard curves were 0.9997, 0.9997 and 0.9995. Data collected for each amount for all three curves 

were averaged and re-plotted to yield a composite standard curve. This curve used to calculate the GA3 

content in the tissue extracts was expressed by the following linear equation: 

Y = 12556 X + 91.8; R 2 = 0.9996 

Where y is the integration unit (peak area) and X is the GA3 amount in nanograms. 

The intra-day repeatability and inter-day reproducibility of retention times and peak areas 

showed mean coefficients of variation of less than 3.0% for all samples. 

Quantification of gibberellic acid in plant tissue samples 

Potato tissue samples were subjected to the extraction procedure as described above. The method 

proposed was then used to determine endogenous GA3 in potato tissue samples. The peak identified as 

GA3 from authentic standard solutions was observed in extracts of leaves and roots from solanum 

tuberosum. Estimations were based on the average of three independent analyses of three replicate 

samples. 

Quantitative analysis (including recovery) of GA3 in the extraction procedure was obtained by 

three ways: (1) a homogenized potato tissue sample spiked before the extraction procedure with a 

known amount of internal standard (500.0 ng) and synthetic GA3 (500.0 ng); (2) the extract of a second 

sample from the same tissue spiked after the extraction procedure, and before the GC-MS analysis, 

with the same amount of the internal standard and synthetic GA3; (3) the extract of a third sample from 

the same tissue plus the same amount of internal standard without added GA3. Quantitative 

determinations performed in these three extracts gave recoveries for the extraction procedures as well 

as the amount in the original sample of potato tissue.


The results obtained for all samples had a deviation below 3% suggesting a high precision in 

the quantification. The percentage mean recovery from extracts spiked with authentic GA3 was 94.0 ± 

2.0 % determined in 6 runs. All measured amounts were corrected for the % recovery. 

Method validation 

7-Hydroxycoumarin-4-acetic acid, which was not detected in potato extract, was selected as internal 

standard for endogenous GA3 because it contains structural features that are similar to those present in 

GA3 and thus its extraction behavior resembles that of GA3. Consequently, the recovery of this 

compound is indicative of the recovery of GA3 during the analytical procedure. 

The composite calibration graph was used to determine GA3 in synthetic samples of known 

concentrations to further determine the accuracy and precision of the method. On the other hand, to 

assess the effect of the sample matrix on accuracy and precision, known amounts of GA3 spiked in 

potato tissues were separately determined. Results are shown in Table 1. Each result was obtained from 

3 independent determinations (triplicate samples per day X 3 injections per sample). 

Table 1: Precision (as RSD %) and accuracy (as relative Error %) of the proposed method for GA3 analysis 

Matrix Spiked amount (ng) Determined amount(ng) RSD (%) Error (%) 

Solvent 100.0 98.0 3.0 -2.0 

Solvent 150.0 147.6 1.3 -1.6 

Solvent 200.0 202.8 2.9 1.4 

Spiked tissue 100.0 98.7 3.2 -1.3 

Spiked tissue 150.0 146.6 1.5 -2.3 

Spiked tissue 200.0 203.6 3.1 1.8 

Mean of 3 independent analyses in triplicate over 3 days (one replicate X 9 injections each day) 

RSD % = relative standard deviation of the mean 

The precision expressed as the relative standard deviation (RSD %) and the accuracy (% error) 

of the method were less than 3% for all samples. Such relatively low deviations and errors indicate a 

high precision and accuracy in the quantification method. 

The determined amount of GA3 in potato tissues was directly obtained from the measurement 

of its peak area and the calibration equation. The amount of GA3 spiked in the tissue extract just before 

GC-MS analysis was obtained from the total determined amounts of GA3 after spiking minus the 

determined original amount of GA3 in the tissue. Peak purity by GC-MS showed peak homogeneity 

thereby excluding the possibility of the presence of interfering components and demonstrating the 

specificity of the method. 


I. Levels of gibberellic acid in potato tissues 

In this study we measured the levels of GA3 in potato (Solanum tuberosum cultivar “Russet Burbank”) 

plants grown differentially under tuber inducing and non-inducing conditions. 

We specifically chose to analyze GA3 for two reasons. First, it is the most widely known GA 

with inhibitory effect on tuberization established by experimentation with exogenous application to 

plant systems. Secondly, it is reported that GA3 promotes root growth in plants (Tanimoto 2005) and at 

the same time gibberellins are thought to be responsible for stolon growth in potato plants (Smith and 

Rappaport, 1969; Kumar and Wareing, 1972). Consequently, a screening of such hormone for its 

endogenous levels in the whole plant system within a time course experiment may be advisable. 

The effect of induction on endogenous levels of GA3 as influenced by photoperiod and 

temperature, induction duration, and tissue location (aerial and underground) can be inferred from the 

data listed in Table 2. Our data support the hypothesis that day length and temperature control the



biosynthesis of GA3 in potato tissues. Level of GA3 was 3 times higher in tissues grown under noninducing 

conditions (10 h photoperiod / 14 h darkness, 24/12ºC day/night) than in those grown under 

inducing conditions (18 h photoperiod / 6 h darkness, 30/26ºC day/night) throughout the time-course 

experiment. Following transfer to inducing conditions, GA3 production was transiently reduced with 

the highest rates of decline observed immediately after transfer. 

It is worth mentioning that gibberellins in other plant species have been reported to be under 

photoperiodic and thermal control. For instance, photoperiod affects certain steps in the GA 

biosynthetic pathway in various species such as spinach (Talon et al. 1991), willow (Olsen et al. 1995), 

and tulip (Aung et al. 1969). 

Comparing the tissue types, GA3 was more abundant in the aerial than in the underground 

tissues. Our results correlate a decreased GA3 content with tuber induction in potato plants. 

Table 2: Levels of gibberellic acid (GA3) in potato tissues under tuber inducing and non-inducing conditions 

Amount (ng GA3/g dry tissue) a,b 

Induced Tissue Non-induced Tissue 

Harvest Days Aerial Underground Aerial Underground 

2 312.3 ± 5.0 a 210.8 ± 3.4 a 668.0 ± 4.0 a 470.2 ± 3.1 a 

4 250.8 ± 4.1 b 150.6 ± 1.7 b 630.2 ± 3.8 a 467.3 ± 2.9 a 

6 210.0 ± 3.9 c 110.2 ± 1.4 c 640.0 ± 3.1 a 460.2 ± 3.0 a 

8 195.4 ± 2.4 c 108.0 ± 1.6 c 645.4 ± 3.4 a 454.5 ± 3.2 a 

10 190.2 ± 1.9 c 106.4 ± 1.4 c 654.6 ± 3.0 a 455.7 ± 2.8 a 

Meanc 231.7 y 137.2 z 647.6 w 461.6 x 

a 

The data are presented as the mean ± standard deviation of three replicates (two independent determinations per replicate) 

b 

Mean values followed by the same letter within a column are not significantly different by Duncan’s multiple-range test at 

P < 0.05 

c 

Mean values in the last row with different letters (wxyz) are significantly different by Duncan’s multiple-range test at P < 

0.05 

II. Physiological significance of the present findings 

The content of GA3 was relatively high, but did not significantly change during the sampling period 

under non-inducing conditions, which promote stolon elongation (Smith and Rappaport, 1969; Kumar 

and Wareing, 1972). However, GA3 level declined very rapidly to a relatively low level after transfer to 

inducing conditions. Clearly, this decline suggests a regulating (inhibitory) role for GA3 in tuber 

induction. It appears that induction of tubers might occur only when the amount of endogenous GA3 

(and/or sensitivity of responsive tissues) in the apical part of the stolons has dropped below a certain 

threshold/critical value. This minimum concentration (sensitivity) model is in line with the observation 

that gibberellins are found to inhibit cytokinin-mediated tuberization of Solanum tuberosum (Hussey 

and Stacey 1984). Furthermore, the inhibitory effect of GA3 was relieved by the addition of equal 

amount of abscisic acid to the culture medium (Xu et al. 1998a). 

The action of GA3 appears to take place through modulating its level and sensitivity by the 

environmental conditions. For example, a decrease in GA3 in below ground tissues has been associated 

with tuber induction. At the same time, the relatively higher levels in above ground tissues might 

support the initial increase in stem elongation; a short-term adaptive response of potato plants to tuberinducing 

conditions (Martinez-Garcia et al. 2002). 

Our findings reinforce earlier reports in the literature and provide supportive evidence for the 

inhibitory effect of GA3 on tuber induction. For example, exogenous application of GA3 to potato


plants is reported to have a promoting effect on stolon elongation (Smith and Rappaport, 1969; Kumar 

and Wareing, 1972) and an inhibitory effect on tuber induction (Hussey and Stacey 1984; Fernie and 

Willmitzer, 2001; Xu et al. 1998a). Furthermore, treatments with inhibitors of gibberellins biosynthesis 

caused tuberization of solanum tuberosum plants under non-inducing conditions (Jackson and Prat 

1996; Hussey and Stacey 1984; Menzel 1980; Vreugdenhil et al. 1994). In addition, suppression of GA 

20-oxidase, a key regulatory enzyme in the biosynthesis of gibberellins, was found to be correlated 

with tuber induction in potato (Carrera et al. 1999). 

Transgenic plants over-expressing this enzyme gave taller plants that tuberized later than 

control plants (Carrera et al. 2000). This observation resembles the effect of exogenous application of 

GA3 on ordinary (untransformed) plants. The observation that taller plants were observed is consistent 

with the promoting effect of GA3 on vegetative growth of plants concurrent with the inhibitory effect 

on tuber induction. 

Interrupting a tuber inducing long night with a red light treatment (which activates 

phytochrome photoreceptors) for few minutes had an inhibitory effect on tuberization (Batutis and 

Ewing 1982; Amador et al. 2001). This effect was similar to that of lengthening the photoperiod. It is 

also reported (Amador et al. 2001) that transgenic plants suppressed with phytochrome B levels 

produced tubers when grown under long nights supplemented with a night-break red light. The red 

light effect was observable 2 days after the short-day treatment started and preceded tuber initiation. 

Our interpretation of such observation is that red light activates phytochrome B to initiate the 

biosynthesis of GA3; the 2-day interval was sufficient to bring GA3 back to the critical inhibitory level. 

In our experiment, we found that 2 days after initiating the inducing conditions the level of GA3 

declined to below inhibitory level required for tuber induction. It is reported that gibberellin activity, 

determined by bioassays, declined in leaves exposed to inducing conditions and as few as 2 days in 

inducing conditions caused a decrease in the gibberllin activity of andigena leaves (Railton and 

Wareing 1973). Gibberellin activity has also been reported by other researchers to be lower in plants 

grown in tuber-inducing conditions compared with non-inducing conditions (Smith and Rappaport 

1969; Kumar and Wareing 1974; Krauss and Marschner 1982; Machachova et al. 1998). In fact, small 

visible tubers were observed 8 days after initiating tuber-inducing conditions in the present experiment. 

Transgenic S. tuberosum ssp. andigena plants inhibited in phytochrome B expression lost their 

photoperiodic sensitivity and consequently tuberized equally well under both non-inducing and 

inducing conditions (Jackson and Prat, 1996; Jackson et al. 1996; Jackson et al. 2000). These 

transgenic plants suppressed with phytochrome B suggest that phytochrome B either regulates the 

production of a graft transmissible inhibitor of tuberization (Jackson et al. 1998; Suarez-Lopez 2005) 

or is required for phloem loading of this inhibitor in the leaves (Suarez-Lopez 2005). When this finding 

is combined with the present result, we find it reasonable to suggest that Phytochrome B is involved in 

the production of the inhibitor GA3 in non-inducing conditions. This suggestion is in line with 

transgenic potato plants enhanced with phytochrome B level which showed increased tuber yield in 

experiments performed both in greenhouse (Jackson et al. 1996; Thiele et al. 1999) and under field 

conditions (Boccalandro et al. 2003). We, therefore, propose that enhanced levels of phytochrome B 

cause the production of more GA3, which in turn promotes stolon elongation (Xu et al. 1998a) that is a 

pre-requisite for tuber induction thus increasing the potential sites for tuberization. 

Conclusion 

Supportive evidence has been obtained for the effect of photoperiod and temperature on GA3 level in 

potato plants (Solanum tuberosum cultivar Russet Burbank) grown in a controlled environment plant 

system. Our study has established a strong correlation between lower GA3 level and tuber induction. 

GA3 was more prevalent in tissues grown in non-inducing conditions and its level declined 3 folds 

upon transferring the plants to inducing conditions. These results demonstrate that the sustained 

decrease of GA3 is required for tuber induction and that its involvement is restricted to the phase 

preceding tuber induction, which is stolon elongation.



The striking correlation between the increased level of GA3 during longer photoperiods with a 

relatively high temperature environment and the absence of tuberization strongly support the 

conclusion that the inhibitor of tuberization produced in the leaves under non-inducing conditions is at 

least in part GA3.


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ISSN 1450-216X Vol.14 No.3 (2006), pp. 417-425 



Research of the Characteristics of a Solar Panel Radiated with 

Со2 Laser, as Means for Injection on Fading Satellites 

M. Zamfirov 

Department of Aerospace Control Systems, Space Research Institute 

Bulgarian Academy of Sciences 

E-mail: mzamfirov@space.bas.bg 

Abstract 

The article discusses the results achieved after a radiation of a solar panel with СО2 

laser and covers the short circuit, the floating voltage, and the efficiency. Theoretical 

deduction of the most appropriate laser wavelength, referred to the maximum of 

transformation of the laser energy in electrical energy for the mono crystal silicon is 

presented. The volt-ampere characteristics of the photo receiver are described. 

Keywords: Satellites, Laser radiation, CO2 – laser, Solar panel 

Introduction 

The research of the influence of the laser radiation on photo voltage systems is important, providing 

energy for existing satellites in the end of their life, due to reduction of the energy system [1]. This 

type of radiated laser energy has a great commercial value [2]. The laser radiation is preferable because 

of the high efficiency of the silicon cells under monochromatic lightening [3], and the possibility of 

increasing the energy, in order to produce more energy outcome per area [4]. 

Exposition 

For calculating the most appropriate laser wavelength, relevant to the maximum of the transformation 

of the laser energy to electric energy, we use the following formula: 

c 

Е = Ћ.ν = Ћ (1) 

λ 

where 

Е – еV 1,610 -19 С (coulomb); 1 V = 1,6.10 -19 J. 

Hence: 

Е [eV] = 6,6.10 -19 J.s/1,6.10 -19 J. 3.10 8 m/s/ λ [nm] = 1,2375// λ [nm] = 

1, 

24 

= 

(2) 

λ[ 

nm] 

Consequently: 

1, 

24 1, 

24 

Е = = λ = 

(3) 

λ E[ 

eV ] 

Where Е is the width of the forbidden area of the semi-conductor. 

For silicon Е = 1,11 eV


Means for Injection on Fading Satellites 418 

Therefore for the maximum of the transformation of the laser energy to electric energy for the 

mono crystal silicon, the wavelength is used: 

1, 

24 

λ = = 1, 

117nm 

(4) 

1, 

11 

Laser with carbon dioxide 

The most appropriate laser for injection on fading satellites is СО2 – laser, where the amplification is 

approximately λ = 1006 nm, i.e. this is the closest value provided for the maximum of the 

transformation of the laser energy into electric energy for the silicon semi-conductor. 

CO2 – lasers generate a broad range of lines in the scope between 900 nm up to 1100 nm. The 

strongest amplification is at 1060 nm. They are characterized with strong efficiency, reaching up to 20 

% for well constructed models. 

The laser used (Model L 1000) has longitudinal smoldering discharge and fast longitudinal 

channel; λ = 1060 nm; Output power by specification - 1000 watts; Laser environment – carbon 

dioxide; Mod –TEM01; Diameter of the output ray – 15mm; Beam divergence – 2 mRad; Polarisation 

– circular. 

The СО2 has more homogeneous and active environment and provides more qualitative and 

direct radiation. It has better mode structure and better focusing [5]. 

Solar panel 

The silicon is the main semi-conductor material for photoelectric transformation of the solar energy 

[6]. 

The direct transformation of the solar energy into electric energy can be achieved with solar 

batteries, consisting of multitude of photo elements, through the so called photovoltaic effect [7]. 

The model of the used solar panel is 685-SP-120-12 V; Voltage – 12 V; Current Voc – 120 µA; 

Voltage (MAX) Voc – 16 V; Current (MAX) Isc; Size 15.9 x 27.8 x 1.7 cm 

The solar panel consists of 36 consequently connected photo elements, which aim at the 

increasing of the output voltage. 

Resistors 

R1 = 33 κΩ; R2 = 77 κΩ; R3 = 143 κΩ; R4 = 308 κΩ; R5 = 406 κΩ; R6 = 503 κΩ; R0 = 0; R = ∞ 

Meanings 

Rel – Electric power; Rl – laser power of the successive line of generation; η, % - efficiency; 

η = Rel /Rl.100; 

Rel = I.U – electric power. 

Experiment 

In front of the СО2 laser a defocusing lens is set, that allows a spot with diameter 5 cm and 25 cm. The 

photo converter is set at 150 cm distance from the lens. Ampere meter, voltmeter and resistors for 

measuring of the current are plugged into the photo converter.

419 M. Zamfirov 

Figure 1: Scheme of the experimental setting 

Picture 1: General view of the СО2 laser. 

Picture 2: Transverse view of the СО2 laser.



Picture 3: Defocusing lens. 

Picture 4: CPU of the laser


Results 

Table 1: Electricity, voltage, electrical power and efficiency of the photo voltaic panel radiated with CO2 laser 

with diameter 5 cm and 25 cm at 0.5 W power. 

D= 5 cm, 10,6 µm, W = 0.5 D= 25 cm, 10,6 µm, W = 0.5 

R I, µA U, V P, µW η % I, µA U, V P, µW η % 

R1 192.15 6,1 1171,115 0.2 1381.25 32.5 44890.625 8.98 

R2 90.39 6,9 623.691 0.1 785.66 32.6 25612.516 5.12 

R3 51.62 7,2 371.664 0.07 592.342 32.6 19310.35 3.86 

R4 35.77 7,3 261.121 0.05 508.959 32.01 16291.778 3.26 

R5 26.64 7,2 191.808 0.04 482.16 32.8 15814.848 3.16 

R6 22.77 7,8 177.606 0.03 457.968 32.9 15067.148 3.02 

R0 985.75 6906.25 

R 10.01 0.082 36.08 4.567 


with diameter 5 cm and 25 cm at 2.2 W power. 

D= 5 cm, 10,6 µm, W = 2.2 D= 25 cm, 10,6 µm, W = 2.2 


R1 203.52 6,4 1302.53 0.04 1423.75 33.5 47695.625 2.17 

R2 92.63 7,01 649.34 0.03 829.92 33.6 27885.312 1.27 

R3 54.79 7,6 416.4 0.02 590.52 32.5 19191.9 0.87 

R4 36.75 7,5 275.63 0.013 511.98 32.2 16485.756 0.75 

R5 30.02 7,9 237.16 0.011 485.25 33.01 16018.103 0.73 

R6 23.76 8,03 190.79 0.0087 460.06 33.05 15204.983 0.69 

R0 1019.64 7147.225 

R 11.1 0.024 36.5 0.98 


with diameter 5 cm and 25 cm at 50 W power. 

D= 5 cm, 10,6 µm, W = 50 D= 25 cm, 10,6 µm, W = 50 

R I, µA U, V P, µW η % I, µA U, V P, µW η% 

R1 220.8 6.9 1523.52 0.03 1478.22 34.7 51294.23 0.102 

R2 94.9 7.3 692.77 0.013 836.27 34.7 29018.57 0.058 

R3 56.72 7.9 448.08 0.0089 614.146 33.8 20758.13 0.041 

R4 40.05 8.01 320.801 0.0064 540.76 34.01 18391.25 0.036 

R5 31.16 8.2 255.51 0.0051 501.27 34.1 17093.31 0.034 

R6 24.03 8.2 197.046 0.0039 473.56 34.02 16110.51 0.032 

R0 1126.08 7234.57 

R 12.03 0.019 37.03 0.051 



D= 5 cm, 10,6 µm, W = 100 D= 25 cm, 10,6 µm, W = 100 


R1 221.7 6.9 1529.73 0.01 1403.78 33.03 46366.85 0.046 

R2 97.24 7.4 719.58 0.007 841.1 34.9 29354.39 0.029 

R3 56.81 7.9 448.8 0.0004 634.13 34.9 22131.24 0.022 

R4 40.18 8.2 329.476 0.0003 553.32 34.8 19255.54 0.019 

R5 30.7 8.3 254.81 0.0002 498.33 33.9 16893.34 0.0168 

R6 23.94 8.2 196.308 0.0001 475.7 34.1 16221.4 0.0162 

R0 1152.8 7299.66 

R 12.6 0.003 36.8 0.025





D= 5 cm, 10,6 µm, W = 250 D= 25 cm, 10,6 µm, W = 250 


R1 217.35 6.9 1499.71 0.00059 1423.63 33.1 47122.15 0.018 

R2 95.63 7.3 698.1 0.00027 830.99 33.2 27589.07 0.011 

R3 56.64 7.9 447.46 0.00017 623.23 34.3 21376.79 0.0085 

R4 39.69 8.1 321.47 0.00012 545.98 34.06 18596.01 0.0074 

R5 29.97 8.1 242.76 0.000097 523.26 34.2 17895.49 0.0071 

R6 23.94 8.2 196.31 0.00078 478.42 34.1 16314.12 0.0065 

R0 1130.22 7317.81 

R 12.5 0.001 36.08 0.01 



D= 5 cm, 10,6 µm, W = 500 D= 25 cm, 10,6 µm, W = 500 


R1 210.8 6.8 1433.44 0.00028 1438.18 34.08 49013.17 0.0098 

R2 95.99 7.3 700.73 0.00014 849.92 33.2 28217.34 0.0056 

R3 57.58 8.02 461.79 0.00092 641.28 33.4 21418.75 0.0042 

R4 35.5 7.9 280.45 0.00056 588.12 34.8 20466.57 0.0041 

R5 31.16 8.2 255.51 0.00051 555.45 34.5 19163.02 0.0038 

R6 23.81 8.1 192.86 0.00038 519.11 34.7 18013.12 0.0036 

R0 1138.32 7622.35 

R 12.6 0.001 36.1 0.03 

Figure 2: Dependency of Uo/Pl from the power at various diameters of the laser spot. 

Uo/Pl, 

V 

80 

75 

70 

65 

60 

55 

50 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

-5 

0 100 200 300 400 500 

W 

d=5 cm 

d=25 cm


Figure 3: Dependency of the Io/Pl from the power at various diameters of the laser spot. 

Io/Pl, 

microA 

14000 

12000 

10000 

8000 

6000 

4000 

2000 

0 

-2000 

0 100 200 300 400 500 

W 

d=5 cm 

d= 25 cm 

Figure 4: Dependency of the efficiency at various diameters of the laser spot. 

efficiency, % 

5 

4 

3 

2 

1 

0 

0 100 200 300 400 500 

% d=25 cm 

% d= 5 cm 

Figure 5: Volt-ampere characteristics for СО2 laser at various power and diameter of 5 cm. 

I, 

mi 

cr 

oA 

250 

200 

150 

100 

50 

W 

W=0.5 

W=2.2 

W=50 

W=100 

W=250 

W=500 

0 

6.6 6.8 7.0 7.2 7.4 7.6 7.8 8.0 8.2 8.4 

U,V



Figure 6: Volt-ampere characteristics for СО2 laser at various power and diameter of 25 cm. 

I,microA 

1600 

1400 

1200 

1000 

800 

600 

400 

W=0.5 

W=2.2 

W=50 

W=100 

W=250 

W=500 

33.0 33.5 34.0 34.5 35.0 

Analysis of the results 

The following quantities can be brought into use, that characterize the panel’s quality to transform the 

laser light into electric one, depending on the diameter of the laser spot and the power of the laser 

emission. These are the ratio between the floating voltage and the laser’s power U0/Pl, and the current 

I0/Pl, that results from the short circuit. During laser radiation at 0.5 W the floating voltage for a 25 cm 

spot is 3.6 times greater than the one for a 5 cm diameter spot. The values for the short circuit current 

for a spot of 25 cm are approximately 7 times bigger. As the laser power increases there is no 

significant increase of the floating voltage and the short circuit current – 36 V and 7 mA for 25 cm and 

12 V and 1 mA for 5 cm at 0.5 up to 500 W power. 

The values of the electric power of the solar panel at 0.5 W radiation are more than 38 times 

bigger at 25 cm diameter of the laser spot than these at 5 cm, for resistance R = 33kΩ (Table 1). 

The difference between the electric power at 5 and 25 cm increases with the increase of the 

resistance and at R= 503 kΩ the electric power is 85 times bigger. This ratio (Р5cm- Р25cm), is preserved 

more or less unchanged at every value of the laser’s power (Table 2,3,4,5.). 

The efficiency, which is the most important characteristic of the researched system, varies from 

8,98 % for 25 cm diameter of the spot to 0,2 % for 5 cm diameter of the spot at R = 33kΩ. The 

efficiency gradually decreases with the increase of the resistance reaching 3,02 % for 25 cm and 0,03 

% for 5 cm (Table 1). 

With the gradual increase of the laser’s power from 0,5 W to 500 W the electrical power of the 

photo converter increases as well with approximately 3 mW, but thus reducing the efficiency. The 

lowest efficiency values of the photo converter are achieved at the highest level of the laser emission’s 

power (Table 5, Fig. 4). 

The volt-ampere characteristic of the photo element, at 5cm laser spot diameter (Fig. 5) shows 

relative nonlinearity. Certain saturation is indicated at the higher voltage values. For 25 cm laser spot 

the volt-ampere characteristic is S-shaped, and the saturation is measured again at the lower current 

and the higher voltage values. Nonlinearity probably results from the raised temperature of the 

selective coverage, which causes emission of heat, thus increasing the resistance causing the current to 

stop decreasing linearly, but keep same values (Fig. 6). 

Conclusions 

The analysis of the results shows that the usage of a wavelength, close to the theoretically deduced one, 

increases the photo element efficiency. In the same time the results suggest that for producing high 

efficiency higher power is not necessary. 

U,V


References 

[1] Landis, G. (1991) Space Power by Laser Illumination of Photovoltaic Arrays Space 

Photovoltaic Research and Technology, NASA CP-3121, 24-5, May 

[2] Backus C. (1972) Laser Activation of Solar Cells Proceedings of the 9th IEEE Photovoltaic 

Specialists Conference, Silver Spring, May 

[3] Friedman, H., et al. (1994) Scaling of Solid-state Lasers for Satellite Power Beaming 

Applications SPIE Optics, Electro-optics & Laser Conference, Los Angeles CA, Jan. 24-28; 

[4] Lowe, R., G. Landis and P. Jenkins (1995) Response of Solar Cells to Pulsed Laser 

Illumination IEEE Transactions on Electron Devices, Vol. 42, No. 4 

[5] Rahilly, W. (1975) Electron Damage in High Efficiency Solar Cells High Efficiency Silicon 

Solar Cell Review NASA Technical Memorandum TM X-3326 

[6] Peter, U. and R. Morgan (1991) SDIO Ground-based Laser Support Laser and Power 

Technology, Volume VIB 

[7] Zamfirov, М. (2003) Problems and concepts of the development of Solar Power Satellite 

Aerospace research in Bulgaria, vol.17,


ISSN 1450-216X Vol.14 No.3 (2006), pp. 426-433 



Feature Selection Based on Statistical Analysis 

Nooritawati Md Tahir 

Dept. of Electrical, Electronics and Systems Faculty of Engineering 

Universiti Kebangsaan Malaysia 43600 Bangi, Selangor DE 

Email: norita@vlsi.eng.ukm.my, norita_tahir@yahoo.com 

Tel:603-89216035; Fax:603-89216146 

Aini Hussain 



Tel:603-89216035; Fax:603-89216146 

Salina Abdul Samad 



Tel:603-89216035; Fax:603-89216146 

Hafizah Husain 



Tel:603-89216035; Fax:603-89216146 

Mohd Yusof Jamaluddin 



Tel:603-89216035; Fax:603-89216146 

Abstract 

In most pattern recognition (PR) system, selecting the best feature vectors is an 

important task. Feature vectors serve as a reduced representation of the original data that 

facilitate us to evade the curse of dimensionality in a PR task. In this work, we deem 

further endeavor in selecting the best feature vectors for the PR task that is to determine the 

best eigenfeatures of four main human postures based on the rules of thumb of Principal 

Component Analysis namely the KG-rule, Cumulative Variance and the Scree Test. 

Accordingly, all three rules of thumb suggest in retaining only 9% of the total eigenvectors 

or also known as ‘eigenpostures’. Next, these eigenpostures are statistically analyzed prior 

to classification. Thus, the most relevant component of the selected eigenpostures can be 

ascertained. The statistical significance of the eigenpostures is determined using ANOVA. 

Further, a Multiple Comparison Procedure (MCP) and homogeneous subsets tests are 

performed to determine the number of optimized eigenpostures for classification. These 

optimized eigenpostures will feat as inputs to the Artificial Neural Network (ANN) 

classifier. The statistical analysis has enabled us to perform effectively the selection of 

eigenpostures for classification of human postures.

Feature Selection Based on Statistical Analysis 427 

Keywords: Statistical Analysis, ANOVA, Principal Component Analysis, Artificial 

Neural Network. 

Introduction 

Pattern recognitions (PR) are defined as a perception task that perceives patterns in terms of 

characteristic attributes, or features, and classifies these features into distinct classes [1]. A 

fundamental pattern recognition system includes two principal processes: feature extraction and 

classification. As we know, the purpose of feature extraction is to characterize attributes pattern 

belonging to a class. If a complete set of discriminatory features for each pattern class can be found, 

classification can be reduced to a simple matching process or a table look-up scheme. However, this 

assumption is really too quixotic to be achieved in practical pattern recognition problems. Therefore, 

only some, or the best discriminatory features are usually adopted. As for classification, its aim is 

similar to that of feature extraction, which is to find the best class that is the closest to the classified 

pattern. One of the issues that necessitate careful thought in a PR system is feature extraction and 

selection. Feature selection entails the task to select a subset amongst a set of candidate features that 

performs best under a classification system. This procedure can lessen not only the cost of recognition 

by reducing the number of features that need to be collected, but in some cases it can also afford better 

classification accuracy [2]. This is the typical PR framework. Conversely, the Principal Component 

Analysis (PCA) is an eminent technique that has found great attentions in fields such as face 

recognition [13], face pose classification [14], facial expressions [15], gesture recognition [16] and 

detection of human activities [17]. However, the actual number of principal components or eigenvalues 

to be retained in past work is vague. In this study, we deem further effort in selecting the best feature 

vectors for the PR task based on the rules of thumb of PCA and performed Statistical Analysis prior to 

classifications. In doing so, the most relevant component of the selected eigenvectors for classification 

can be revealed. The structure of this paper includes materials and method in next section followed by 

results and finally we conclude our findings. 


System Overview 

Figure 1 depicts an overview of the overall PR system that outlines the basic structure. To illustrate the 

significance of our additional effort, we implement a PR task that handles a large database of human 

posture images namely standing, sitting, bending and lying as illustrates in Figure 2. The preprocessing 

stage consists of segmentation, feature extraction and feature selection. This phase extorts the 

silhouette of a person which incorporate background subtraction followed by thresholding. Median 

filtering and morphological operations are utilized for noise removal.

428 Nooritawati Md Tahir, Aini Hussain, Salina Abdul Samad, 


Figure 1: Overview of the overall PR system 

Raw 

Image 

Pre Processing 

- Background 

Sub traction 

- Thresholding 

- Morphological 

Ops 

Feature 

Extraction & 

Selection 

- Eigenposture 

Gen eration 

- Scree Te st, KG 

Rule and Cum 

Variances 

Statistical 

Analysis 

- ANOVA 

- MCP Test 

Figure 2: Some of the human shapes silhouette as training images 

ANN 

As 

Classifier 

Next, the feature extraction component functions by projecting the training images onto a 

feature space that spans the significant variations among known images. The significant features, 

which we termed as 'eigenpostures' are the eigenvectors (principal components) of the set of images. 

Detail description of the eigenpostures approach can be found in [3]. The eigenpostures will undergo 

the feature selection process according to the rules of thumb of PCA. The feature vectors comprise of 

the eigenpostures extracted from the images are then statistically analyze prior to classification. 

Principle Components (Eigenvalues) Selection 

It is an eminent fact that the main aim of PCA is to reinstate the p-dimensional feature space with a 

much smaller m-dimensional feature space, which nonetheless discards little information. For most 

empirical data, a large part of the total variance can be sufficiently estimated with the first few 

principal components only. However, the actual number of principal components to be retained is 

indistinct. Several rules of thumb have been anticipated in literatures that include the followings: 

a) Scree Test involves looking at the plot of the eigenvalues λi against the factor number k. The Scree 

Test involves a certain degree of subjectivity since there is no formal numerical cut-off based on 

the λi. The idea behind the Scree Test is that important factors have a large eigenvalue and as such 

explain a large part of the total variance. If the eigenvalues are plotted, they form a curve heading 

towards almost 0% variance explained by the last dimension. Thus, the point at which the curve 

levels-out, sometimes referred to as the ‘elbow’ indicates the number of useful PCs, which are 

present in the data [5][8][10]. 

b) Kaiser Gutman (KG) rule states that any PC with a variance of less than one contain less 

information than the original variables and is therefore not worth retaining. In other words, the


KG-rule retains only those PCs whose variances, i.e. eigenvalues that are ≥ 1. Nevertheless, for 

large variable spaces p, the KG-rule usually retains too many PCs [4], [8][10]. 

c) Cumulative Variance utters the criterion for choosing m is to select a cumulative variance 

threshold, t where t is at certain percentage of the total variance that the first m PCs should account 

for. The required number of PCs is then the smallest value of m for which the chosen percentage is 

exceeded [7][10]. From PCA theory, the variance of the i-th PC (eigenvector) is equal to its 

corresponding eigenvalues λi [6]. 

Three different methods have been elucidated on how to retain the optimal number of PCs. In 

this study, we investigated the required number of PCs to be retained using these three methods. 

Statistical Analysis 

ANOVA is a standard technique for measuring the statistical significance of a set of independent 

variables. It takes a single feature and the class associated with the data samples and measures the 

significance of the class variables in predicting the means of the feature. The measure that ANOVA 

produces is the p-value for the feature set. On the other hand, Multiple Comparison Procedure (MCP) 

test is one that can be used to determine which means amongst a set of means differ from the rest. The 

ANOVA leads to a conclusion that there is evidence that the group means differ but the main goal is to 

determine which of the means are different. Therefore, the MCP is applied. 

The MCP test compares the difference between pair of means with appropriate adjustment for 

the multiple testing. The results of MCP present the p-value or confidence interval for each pair. In this 

study, after performing ANOVA on the eigenpostures, MCP is applied to assess which ‘eigenpostures’ 

means are significantly different. Further, multiple range test is realized for testing homogeneous 

subsets of groups based on their group means. In doing so, the groups that differ significantly are 

revealed. Finally, we will determine the optimized number of eigenpostures that will act as inputs to 

the ANN for classification of the four main postures. 

Artificial Neural Network (ANN) as Classifier 

Artificial Neural Networks (ANN) are known for their ability to express highly nonlinear decision and 

makes them appropriate for recognition of complex pattern and the ability to maintain accuracy even 

when some input data are inapt. In this study, the multilayer perceptron is chosen for recognition 

purpose. A multilayer perceptron is a feed forward network structure in which neurons are connected 

only between two succeeding layers [9][12]. A feed forward neural net that performs the recognition 

part consist of one input layer with one neuron per feature, two hidden layers with four and three nodes 

in each layer and a single output. 

Experiments and Results 

A collection of 400 images of various human postures constitutes the database to generate the 

eigenpostures for this study. The various postures include all four main postures namely standing, 

sitting, bending and lying position for both gender with the subjects are either facing front or facing 

either side and no restriction impose on the type of clothing being worn. Initially, each image has m x n 

pixels, but eventually reshaped to a column vector of x mn. Then, the eigenvectors and eigenvalues are 

computed according to [3][11]. Implementing the three rules mentioned previously, we select the most 

suitable eigenpostures required as inputs to the classification system. In other words, we select the 

most relevant eigenvalues or PCs to be retained in this study. 

Figure 3 illustrates the results of the Scree test. The decrease in magnitude for successive 

eigenvalues implies that the first few principal components can approximate a large part of the original 

data’s variance. In this case, decision to retain the first thirty-five PCs is appropriate and they 

reasonably represent good approximation of the original data set. Next, from the PCA results, applying



KG rule that suggested retaining all eigenvalues > 1 results in thirty-five PCs to be considered as 

significant components. The PCs are as tabulated in Table 1. 

Table 1: The significant eigenvalues or PCs using the KG rule. 

Factor k 1 2 3 4 5 

Eigenvalue 44.37 23.64 17.48 12.25 10.32 

Factor k 6 7 8 9 10 

Eigenvalue 9.37 5.77 5.64 5.21 3.89 

Factor k 11 12 13 14 15 

Eigenvalue 3.79 3.17 3.07 2.9 2.64 

Factor k 16 17 18 19 20 

Eigenvalue 2.6 2.48 2.39 2.19 2.02 

Factor k 21 22 23 24 25 

Eigenvalue 1.97 1.77 1.71 1.67 1.63 

Factor k 26 27 28 29 30 

Eigenvalue 1.57 1.42 1.35 1.28 1.26 

Factor k 31 32 33 34 35 

Eigenvalue 1.2 1.14 1.11 1.06 1.01 

Figure 3: Percentage of the total variance accounted by each PCs or eigenvalues using Scree Test. 

Percent of total variance (%) 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

0 

0 5 10 15 20 

Factor No k 

25 30 35 40 

Further, we consider the cumulative variance rule of thumb as our feature selection basis to 

determine the optimum number of eigenvalues or PCs. Figure 4a depicts the overall cumulative 

variance of the eigenvalues of the orthogonal eigenvectors of the human posture database produced in 

this study. The blue solid line represents the cumulative variance whilst the dotted line represents the t 

threshold of 90% for selecting the optimal number of PCs to retain. As suggested in [8], a threshold t 

of between 80%-90% can be considered to determine factor number, k. In this case, a 90% criterion 

would result in k equals 70, thus suggesting that 70 PCs are required to account for more than 90% of 

the total variance and an 80% criterion would result in k equals 34 as depicts in Figure 4b. 

Consequently, all three rules of thumb provide constructive results and in this study, we rule 

that thirty-five PCs are adequate to represent a large part of the variance of the original human postures 

data set. The eigenvectors of these thirty-five PCs that we termed as eigenpostures will undergo the 

statistical analysis prior to classification. Accordingly, we determine the statistical significance of all 

the thirty-five eigenpostures of the four main postures using ANOVA. In this analysis, null hypothesis


Cumulative Variance (%) 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 20 40 60 80 100 120 140 160 180 200 

Factor Number K 

Figure 4: Cumulative Variance Graph 

will be discarded for p-value near zero and suggests that at least one sample mean is significantly 

different from the other sample means. If the PCs are statistically significant, hence the selected PCs 

will undergo the MCP test. Hence, from the ANOVA test, at a significant level of α = 0.05, we 

anticipate that the p-values for eigenpostures 1-9, 11-13, 15-18, and 20-21 are numerically 

indistinguishable from zero, therefore we conclude that a total of nineteen eigenpostures or PCs are fit 

to undergo the MCP. As a result, the ANOVA test has lucratively reduced the feature vectors to 

nineteen or 54% of the initial feature extraction quantity. 

Table 2: Classification results using combination of three eigenpostures. 

(CA = Classification Accuracy) 

Exp No 1 2 3 4 

Eigenpostures Combination / CA (%) E1, E2, E3 E1, E2, E5 E1, E3, E5 E2, E3, E5 

Bending 

100 100 80 85 

93 88 93 78 

Sitting 

Standing 

Lying 

(a) 

t between 80 & 90 % 

Cumulative Variance (%) 

10 

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 

Factor Number K 

98 87 88 82 

95 93 95 67 

In addition, the MCP test is performed to determine the number of optimized eigenpostures for 

classification. Using MCP and homogeneous subset test, we foresee that E1, E2, E3, and E5 are the 

eigenpostures that are significantly different between groups. As a result, the statistical analysis has 

enabled us to perform effectively the selection of only four eigenpostures as inputs to the classifier and 

further lessen the feature vectors to 11% of the initial feature vectors. As aforementioned, Multilayer 

Perceptron (MLP) is chosen as our classifier in this study. In order to develop a classification system, a 

combination of these significant eigenpostures of the training images will serve as inputs to the neural 

network. 

For each experiment, a combination of three eigenpostures according to the MCP and 

homogeneous subset tests are selected as in Table 2 respectively. For this study, 100 sets of each 

posture profile are used for training the ANN and another 100 sets unseen profile of each category will 

be the testing data. The system is trained on the training data and its performance measured on the test 

data. As shown in Table 2, for all four postures, using only the combination of three eigenpostures give 

87% classification results for unseen images of standing and sitting apart from experiment 4. Another 

100 

90 

80 

70 

60 

50 

40 

30 

20 

(b) 

t at 80 %



interesting and remarkable performance is as in experiment 1 that contributed the best classification 

rate in each category. As a result, the combination of E1, E2, E3 is chosen as the optimized 

eigenpostures. 

Conclusion 

In conclusion, a task of classifying four main human postures namely standing, sitting, bending and 

lying position based on eigenvectors analysis is presented. As can be seen from the experimental 

results, eigenspace technique based on statistical analysis prior to classification can be employed for 

human posture classification with high degree of accuracy. The initial thirty five feature vectors 

suggested by the rule of thumbs of PCA namely the KG rule, Scree Test and Cumulative Variance are 

trimmed down to a new subset of twenty feature vectors via the ANOVA. Further, the MCP and 

homogeneous subset tests have lessen the feature selection to only four eigenpostures and confirmed 

that the unseen postures have been correctly classified by using only three combination of 

eigenpostures as inputs to the neural network classifier. E1, E2, E3 are selected as the optimized 

combination. This suggests that the eigenspace technique along with statistical data analysis can be put 

into practice for posture recognition, which can lead to a wide variety of applications such as security 

systems, intruder’s alertness, gait analysis, action recognition, human computer interaction, action 

recognition for surveillance applications and tracking techniques for video coding, and image displays. 

The rules of thumb of PCA and statistical analysis have facilitated us to achieve the selection of 

eigenpostures for classification of human postures efficiently. 

Acknowledgement 

This work was supported by MOSTI under the IRPA Grant No: 03-02-02-0017-SR0003/07-03. The 

authors also acknowledge Prof Dr Burhanuddin Yeop Majlis as the Program Head and UiTM for the 

UiTM-JPA SLAB scholarship awards.


References 

[1] Ani1 K. Jain, Robert P.W. Duin, and Jianchang Mao (2000) Statistical Pattern Recognition: A 

Review. Proceeding of IEEE Transactions On Pattern Analysis And Machine Intelligence Vol. 

22(1): 4-37. 

[2] Laveen Kanal (1974) Patterns in Pattern Recognition. Proceeding of IEEE Transactions on 

Information Theory, Vol. 20(6):697-722. 

[3] Nooritawati Md Tahir, Aini Hussain, Salina Abdul Samad, Hafizah Husain and Mohd Marzuki 

Mustafa (2006) Eigenposture for Classification. Journal of Applied Sciences 6(2):419-424. 

[4] Fekedulegn, B. Desta, Colbert, J.J and Hicks R.R. (2002). Coping with Multicollinearity: An 

Example on Application of Principal Components Regression in Dendroecology in Report of 

Department of Agriculture, Forest Service, Northeastern Research Station, Newton Square, 

USA. pp 2-24. 

[5] Walter J. Freeman (1987).Methods of Analysis of Brain Electrical & Magnetic Signals: 

Analytic Techniques Used in the Search for the Physiological Basis of the EEG, in EEG 

Handbook, Department of Molecular & Cell Biology, University of California, Berkeley, CA 

94720, USA. 

[6] Lewis, A. (2001) Great Barrier Reef Depth and Elevation Model: GBRDEM. in Technical 

Report No. 33, Townsville, CRC Reef Research Centre Ltd. 

[7] http://lertap.curtin.edu.au/HTMLHelp/HTML/index.html?eigenvalues.html (1/2/2006). 

[8] IT Jolliffe (2002). Principal Component Analysis, Springer Series. pp 111-137. 

[9] Tom Mitchell (1997). Machine Learning, McGraw Hill. pp 81 -110. 

[10] Nooritawati Md Tahir, Aini Hussain, Salina Abdul Samad, Khairul Anuar Ishak and 

Rosmawati Abdul Halim (2006). Feature Selection for Classification Using Decision Tree in 

Proceeding of SCORed 2006, Malaysia. pp 99-102. 

[11] Smith L. (2002). A tutorial on Principal Components Analysis, Cornell University, USA, 

http://kybele.psych.cornell.edu/%7Eedelman/Psych-465-Spring-2003/PCA-tutorial.pdf, 

(6/01/2005). 

[12] Winston, P.H. (1992). Artificial Intelligence, 3rd Edition, Addison Wesley. pp 443-500. 

[13] Turk M. (2001). A Random Walk through Eigenspace. Special Issue on Machine Vision 

Applications, in IEICE Transaction Information and System. E84-D (12): 1586-1595. 

[14] Ji Q and X. Yang. (2002).Real Time 3D Face Pose Discrimination Based on Active IR 

Illumination. International Conference on Pattern Recognition, Japan, pp 310-313. 

[15] Ohba K., G. Clary and T. Tsukada (1998). Facial Expression Communication with FES. 

International Conference on Pattern Recognition, Japan, pp 1378-1381. 

[16] Algorri M.E. and A. Escobar (2004). Facial Gesture Recognition for Interactive Applications. 

IEEE Proceedings of Fifth Mexican International Conference in Computer Science, Mexico, pp 

185-195. 

[17] Ozer B. and W. Wolf (2002). Real Time Posture and Activity Recognition. IEEE Proceedings 

on Motion and Video Computing, pp133-138.


ISSN 1450-216X Vol.14 No.3 (2006), pp. 434-438 



Sublingual Schwannoma in a Nigerian African-a Case Report 

Rahman G.A 

Consultant General Surgeon, Dept of Surgery 

University of Ilorin Teaching Hospital 

Ilorin-Nigeria 

E-mail: garahman1@yahoo.com 

Alabi.B.S 

Consultant ENT/Head&Neck Surgeon, Dept of Otolaryngology 

University of Ilorin Teaching hospital 

P.O.Box 4210, Ilorin-Nigeria 

Email: alabibs@yahoo.com 

Afolabi.O.A 

Senior Registrar, ENT/Head&Neck Surgeon, Dept of Otolaryngology 

University of Ilorin Teaching hospital 


Bramoh.K.T 

Consultant Radiologist, Dept of Radiodiagnosis 


Ilorin- Nigeria 

Buhari.M.O 

Consultant Histopathologist, Dept of Morbid Anatomy&Histopathology 



Introduction 

Schwannoma is an encapsulated tumour derived from Schwann cells around the peripheral, cranial and 

autonomic nerves 7 . It generally develops from the sensory nerves, rarely from the motor nerves. One of 

the favoured sites is the head and neck area (25-45%) but occurs intracranially mostly 7 . The incidence 

of Schwannoma in the oral floor is extremely low. It occurs regardless of age or sex grows slowly and 

is usually painless. The tumour may arise at any age, some series have reported that it is common in 

adults in contrast to the neurofibroma, which tends to be commoner in young children. Most reports 

suggest that the majority of the tumours are present between the ages of 10 and 40years 9, 2, 5 . 

The aetiology is unknown, but it is postulated that the lesion arises by the proliferation of 

Schwann cells at one point inside the perineurium of the nerve. There have been approximately 146 

Schwannomas reported from the oral soft tissues 2, 5 . Neurinomas of interest to otolaryngologists are 

usually solitary lesions, they appear encapsulated but may have invasive tendencies and may recur after 

removal 1 .

Sublingual Schwannoma in a Nigerian African-a Case Report 435 

Sonography is the first line imaging modality in assessment of salivary glands. Due to their 

superficial position, the parotid, the submandibular, and the sublingual glands can be imaged with 

high- resolution transducers. 

Sonography enables the diagnosis of cysts or ranulae. Schwannoma appear as a wellcircumscribed, 

circular type mass with smooth margin on images. Tumours of salivary glands can be 

visualized with sensitivity but like other imaging techniques (MRI & CT-Scan) the specificity in 

assessment of the histology of a tumour is low in many diseases 6 .Schwannoma should be suspected in 

the oral floor when a well-circumscribed mass whose margin is smooth shows cystic degeneration on 

MRI 4 . 

These tumours are usually firm to hard in consistency and on section are often studded with 

areas of cystic degenerations, haemorrhage or lipid deposition 8 .Treatment is surgical excision and the 

approach depends on the location and the extent of the tumour and long-term follow-up is necessary 3 . 

This report is on a case of sublingual swelling found to be a Schwannoma in a young Nigerian 

with sonographic findings in a setting with limited diagnostic imaging techniques and a review of the 

literature of this rare tumour. 

Case Report 

O. S. is an 18year old secondary school student who presented July 2002 with a year history of 

swelling under the tongue immediately followed by small rashes and ulcers on the dorsum of the 

tongue. There was no associated pain, dysphagia or breathlessness. He had oral ampiclox capsules and 

paracetamol tablets prescribed in a primary health centre and the rashes and the small ulcers 

disappeared. The Sublingual Swelling progressed and three months before presentation, developed 

difficulty in mastication and dysphagia due to the elevation of the tongue by the swelling. 

Oral cavity examination revealed a sublingual swelling, about 6x 6 cm, mainly to the left of the 

frenulum, well circumscribed, firm in consistency, non- tender, non- fluctuant and the mucosa over it 

was intact and highly vascularised with restricted tongue protrusion. No palpable submental or 

submandibular lymph nodes. No obvious neck swelling. All other systems were essentially normal. A 

diagnosis of sublingual dermoid cyst was made with sublingual thyroid and thyroglossal cyst as 

differentials. 

Sublingual Ultrasound (Fig. I) showed a well-circumscribed sublingual solid mass 6x6cm on 

the left side of the frenulum as shown by the arrow and the right side was normal. Neck ultrasound 

showed normal thyroid gland. Full blood counts and electrolytes and urea with creatinine were within 

normal limits.

436 Rahman G.A, Alabi.B.S, Afolabi.O.A, Bramoh.K.T and Buhari.M.O 

Figure 1:-Ultrasound of the Sublingual Cyst 

He had excision of the mass done under general anaesthesia with cuffed nasotracheal 

intubation. Operative findings were a solid well-encapsulated sublingual mass, mainly on the left side 

of the frenulum but crossing the midline to the opposite side with elevation of the tongue. The postoperative 

period was uneventful except for the mild oedema of the tongue, which completely resolved 

by the 6 th post-operative day. 

Macroscopically, the excised mass was globular, weighed 100grammes, dark brown, 

encapsulated, multinodular in part and appears cystic in other parts. Cut surface mainly solid with a 

few cystic parts and a focus of degeneration towards the periphery. Microscopically, it showed closely 

packed spindled shaped cells with monomorphic cells with dark staining oval nuclei form palisade 

around the eosinophilic filaments (features of Schwannoma). Outpatient visits has been uneventful 

nearly four years after the excision with no evidence of recurrence. 

Discussion 

Schwannoma are usually solitary, encapsulated with whorled arrangement of spindle cells having a 

palisade or regimented appearance seen with staring technique and on electron microscopy 10 . 

Schwannoma is rarely observed extracranially but intracranially, incidence is reported to be high in the 

tongue but extremely rare in the oral floor 7 . Schwannoma cuts across ages 2, 5 , in this report, it occurred 

in a male patient in the second decade of life. The presenting complaints were similar to those reported 

for sublingual masses but no features of upper airway obstruction in this case probably due to the small 

size of the tumour, however, he had dysphagia with superimposed bacterial infection, which improved 

with antibiotic treatment. 

The clinical examination findings of well-circumscribed, non-tender, sublingual cysts with 

tongue elevation are similar to findings elsewhere 11, 6 . The ultrasound findings of a well-circumscribed

Sublingual Schwannoma in a Nigerian African-a Case Report 437 

solids, globular mass with smooth edges are consistent with sonographic findings previously 

documented 4 . 

The histopathological finding of cut surfaces with cystic parts and a focus of degeneration 

towards the periphery is typical of Schwannomas 10 . 

It does not undergo spontaneous reduction or respond to radiation therapy hence complete 

surgical excision is the treatment of choice as done in this case and long-term follow-up is important to 

monitor recurrence 3 . 

Schwannoma is the commonest of the neurogenic tumours in the head and neck, it possesses a 

rare malignant counterpart, which infiltrates adjacent tissues and metastasizes 8 . Our patient is free of 

this nearly four years post excision. 

In conclusion, when a well circumscribed mass with smooth margins and cystic degeneration is 

seen in the sublingual space, as in this case, Schwannoma should be taken into consideration as part of 

the differential diagnosis, ultrasound scan could be quite useful in the diagnostic workup in an 

environment with limited diagnostic facilities and complete surgical excision is the treatment of choice 

with long term follow-up.

438 Rahman G.A, Alabi.B.S, Afolabi.O.A, Bramoh.K.T and Buhari.M.O 

References 

[1] Arda HN, Akdogan O, Arda N, Sarikaya Y, An unusual site for an intraoral Schwannoma: A 

case report. Am J Otolaryngol 2003 Sept-Oct; 24 (5): 348-50. 

[2] Cherrick HM, Eversole LR.Benign neural sheath neoplasm of the oral cavity. Oral Surg Oral 

Med Oral Pathol 1967; 32:900-9. 

[3] El-Saggan A, Olofsson J; Nasosinal Schwannoma: Report of two cases and review of the 

literature (925- N-O) XVII IFOS World Congress, Cairo Sept. /Oct. 2002, 172-73 (abstract). 

[4] Gritzmann N, Rettenbacher T, Hollerweger A, Macheiner P, Hubner E. Sonography of the 

salivary glands, Eur Radiol. May 2003. 13(5): 964-75. 

[5] Hatziotis JC, Asprides H.Neurilemoma (Schwannoma) of the oral cavity. Oral Surg Oral Med 

Oral Pathol 1971; 24:510-27. 

[6] John JB, Tumours and cysts of the face, mouth, Head and Neck, Diseases of the Nose, Throat, 

Ear, Head and Neck, 14th Ed. Lea & Febiger, Pennsylvania, USA, 1991, 332. 

[7] Kawakami R, Kaneko T, Kadoya M, Matsushita T, Fujinaga Y, Oguji K, Kurashina K, 

Schwannoma in the sublingual space, Dentomaxillofac Radiol. 2004 July; 33(4): 259-61. 

[8] Shaheen O.H, Tumours of the infratemporal fossa and Parapharyngeal space, Scott-Browns 

Otolaryngology (Laryngology and Head and Neck Surgery, 6 th Ed, Butterworth - Heinemann 

Oxford, 1997; 5/22/6. 

[9] Shklar G, Meyer I.Neurogenic tumours and jaws. Oral Surg Oral Med Oral Pathol 1963; 

9:1075-93. 

[10] Walter JB, Israel MS. Tumours: Introduction and classification (General Pathology), 5 th Ed, 

Churchill Livingston UK 1979. 319-20. 

[11] 11. Wright BA, Jackson D, Neural tumours of the oral cavity. Review of the Spectrum of 

benign and malignant oral tumours of the cavity and jaws. Oral Surg Oral Med Oral Pathol 

1980; 49:509-22.


ISSN 1450-216X Vol.14 No.3 (2006), pp. 439-446 



Health Impact Assessement of Multinational Corporations Oil 

Exploration in the Niger-Delta Region of Nigeria 

Ewhrudjakpor, Christian 

Senior lecturer, Department of Sociology & Psychology 

Delta State University, P.M.B. 1 Abraka, Delta State, Nigeria 

Email: acadchris@yahoo.com 

Tel: 08035784715 

Abstract 

This study aimed at assessing the multinational oil corporations exploration 

activities impacting on health conditions of the peoples of the Niger Delta region in 

Nigeria. 435 respondents and 65 interviewees selected using the accidental sampling 

technique participated in this study. The structured questionnaire and an interview schedule 

was used to gather data which were analysed using simple percentages and the chi-square 

(X 2 ) statistic. Results (X 2 = (1) 3.87, P < .05; X 2 (7) 361.46, P < .05) obtained shows that 

oil exploration activities impacted negatively on the health conditions of the inhabitants of 

these multinational oil companies host communities. Suggestions to reverse this corporate 

social irresponsibility were proffered. 

Introduction 

The Niger-Delta region is the richest part of Nigeria, yet it is the poorest Okpowo (2002). This is 

paradoxical. This is because, the multinational oil corporations exploit the natural resources-oil, but 

have little or no dividends for the local governments or the host communities. In collaboration with the 

federal government of Nigeria, the oil corporations (Shell Petroleum Development Company Limited, 

Chevron Nigeria Limited, Exxonmobile Nigeria Limited and Texaco Nigeria Unlimited) easily exploit 

and expropriate these Niger-Deltans. 

The totality of these exploitation, expropriation and deprivation is on the health of the people of 

this region. Health is a multi-dimensional variable, it cannot be separated from the human 

environment-whether physical, social, cultural or economic components of the human functioning. 

These components are major determinants of mortality rate globally. These components whether taken 

separately or in combination prolong or eliminates illness or disease. 

Good health is man’s most precious asset. ‘Health is wealth’. The wealth of a nation depends 

on the health of its people. The truth of this phrase is self evident; for the citizens who produce this 

wealth have to be healthy, in body and mind for them to be able to perform their duties effectively. 

Ironically, the citizens who have these oil wealth do not partake in either the production of the refined 

oil or in the sharing of the benefits that comes out of it. This is preposterous. From whence comes the 

wealth. The World Health Organization (WHO) defines health wholistically as: a state of complete 

physical, mental and social well being, and not necessarily, the absence of infirmity or disease. Health 

is the quality of life resulting from the total functioning of the individual in his environment that 

empowers him to achieve a personally satisfying and socially useful life. 

Nigeria’s 1979 constitution not only emphasizes health care as an essential part of socioeconomic 

development, but also places it on the concurrent list. The document specifies that the health


the Niger-Delta Region of Nigeria 440 

care system covers all citizens especially the underprivileged. Also, Nigeria is a member of the WHO 

and a signatory to the World Health Assembly declaration in 1977, that set to eliminate universally all 

forms of disease health by the year 2010. 

Against this background, it is unfortunate to know of the neglected health and sanitary 

conditions of the inhabitants of oil bearing communities in the Niger-Delta region of Nigeria. The 

health status of the peoples of this region has reduced due to the activities of these multinational oil 

companies operating within the region. 

Statement of the Problem 

The health neglect of the inhabitants of the Niger-Delta region in Nigeria is an eyesore. The region has 

been in dire need to improve the quality of sanitation and human lives since the first oil well was 

formally struck at Oloibiri in 1967, despite the huge volume of money and prestige derived from oil 

exploration by multinational oil corporations and the federal government of Nigeria. Today, health 

problems and poor sanitation are major concerns to Niger-Deltans, Environmentalists, Human Rights 

Activist, Social Scientists and Medical experts (Madueke 1960; Atumah, 2005; Okaba, 2005). 

Pollution and environmental degradation by these multi-national oil firms have brought a lot of 

illnesses and diseases to the people of this region, for example diseases and illnesses like dysentery, 

tuberculosis, malaria and hepatitis are amongst the ailments transmitted by sewage in drinking water 

and bathing in lakes and rivers. Health problems reported in Nigeria Dailies (Okpowo, 2002, Afolabi, 

2005), have also assumed unprecedented dimensions with high incidents of asthma, bronchitis, skin 

cancer localized in the Niger-Delta Communities where oil is extracted. 

Oil spills that leads to fire disaster cannot be overlooked, as its effects has led to the death of 

thousands of inhabitants in their host communities like the Jesse (Delta State) spillage in 1998. Despite 

these health neglect there are no corresponding hospitals and clinics to tackle the several health 

problems of these communities (Igun, 1979). 

Consequently, during their exploration activities, they degrade the lands, contaminate the rivers 

and pollute the air, thereby reducing the life expectancy of the inhabitants of this region. It is clear that 

the multi-national oil firms have not met their social responsibilities in terms of health care and 

sanitary conditions to their host communities. 

It is of particular interest to mention and discuss sanitation as a major index of health problems 

in this region. Sanitation here means standards of public hygiene, or measures taken to promote and 

preserve public health. Sanitation cuts across air, water, and land, for example, air is said to be the 

most vital resources needed to sustain life in the biosphere. If deprived or polluted due to gas flaring, 

carbon monoxide (Co3) from heavy machines, nitrogen oxide (No2) affects man in varied degrees from 

dizziness to death by asphyxiation. Also, the poor sanitary conditions of the region have also made 

malaria fever a common disease (this is the number one cause of infant mortality in the Niger-Delta 

region of Nigeria. Improper disposal of industrial petrochemical materials collected and retained in the 

rivers, streams, lakes which eventually serves as breeding places for mosquitoes. 

Another cause of ill-health in this region is the contamination of the water in the region. There 

is water everywhere, but there is no drop to drink. This typifies the unsanitary state of the waters in this 

region. The inhabitants urinate in them, defecate there, oil spills slick the waters, etc, and so there is 

little or nothing to drink or take out of the water for domestic use. Aquatic life is completely destroyed 

whereas the major occupation of this people is fishing. Paradoxically, because the inhabitants are poor 

and the water-table does not allow them own boreholes, they are forced to drink from these heavily 

contaminated water. Drinking, cooking or washing with contaminated water cause several infectious 

diseases that may result to bladder irritation and inflammation with the resultant effect of blood in the 

urine. 

The land in this region also is severely damaged by oil exploration activities. The few 

farmlands are nutrient-less. The vegetation destroyed in the mangrove forest resulting to poor farm

441 Ewhrudjakpor, Christian 

produce. Therefore nutritional produce are very poor, hence poor diet and of course resulting to various 

forms of illnesses from kwashiorkor, (severe malnutrition in infants and children) to stomach ulcer, due 

to severe hunger. 

Studies (Ogege, 2002; Benike, 2002, Jike, 2004), have shown that there have been over 4000 

oil spills and over 100 gas flaring sites in Niger Delta region since 1960. Gas flaring from oil 

extraction has resulted in serious air pollution problems, and have affected the farmlands, vegetation 

and human beings around 1000 metres of its location. These has veritably created serious health 

problems in this region among its inhabitants (Afolabi, 2005). 

This study is aimed at assessing the health neglect by multinational oil firms in host 

communities in the Niger-Delta of Nigeria. Consequently, ways of redressing these social 

irresponsibility of these multinational oil firms shall be proffered. 

Need for the Study 

This study will be of immense help to both the federal government and multinational oil firms in 

strategizing for improving the frayed relationship between the multinational firms and their host 

communities in Nigeria, that has deteriorated to hostage taking and acts of terrorisms (Agbo, 2006) in 

the Niger-Delta region of Nigeria. It will also serve as knowledge base to these multinationals, federal 

government and policy makers in respect of the needed health issues to address, towards ensuring 

improved mortality, fertility and morbidity rates in the impoverished Niger-Delta region. 

Methods 

Population/Sample 

Nigeria’s population is put at about 120,000,000 million people. Nigeria is the most populous nation in 

Africa. It has 36 states. Most states in the south of Nigeria have oil resources. These states are in the 

Niger-Delta region of the south of Nigeria. They are: Delta, Edo, Bayelsa, Rivers, Akwa Ibom, Ondo, 

Abia and Cross Rivers States. 

500 male and female indigenes (literate and non-literate) from five communities in five states 

selected from oil rich states for this research. 

Sampling Technique 

The accidental technique was used to select the 435 respondents and 65 interviewees. That is the 

researcher administered questionnaires or interview schedules to those he met at the time of visit to the 

various communities in the study. 

Instruments: Two instruments were used: the structured questionnaire and the interview schedule. 

The structured questionnaire had 2 sections: section ‘A’ contained demographic information while 

section ‘B’ contained 20 items pertaining to sanitary and health items. 

The interview schedule was the same questions contained in the questionnaire, but because the 

interviewees are illiterates, the researcher gets a translator to translate the questions, and then he ticks 

the appropriate response in the questionnaire. 

Procedure of Study 

The researcher recruited two assistants in each of the five communities investigated. The assistants are 

indigenes and they help in taking the researcher round to conduct the study. They also help in 

translating the questions in their native dialects where necessary. The research assistants were 

remunerated on a daily basis. The study lasted for three months (between November 2005 and January 

2006).



Data Analysis 

The data collected were analysed using the simple percentage and the chi-square (X 2 ) statistical 

technique. 

Results 

The data collected and statistically analyzed are presented here. 

Table 1: Demographic Distribution of Respondents. N=500 

ITEMS NO PERCENTAGE 

SEX 

Male 283 56.60 

Female 217 43.40 

Age 

< 20 164 32.80 

20


Table 2: Frequency Distribution by sex of the inhabitants Assessment of the impact of Oil Exploration on 

Health of Host Communities 

Variables No Frequency Yes Frequency No Total 

Male 283 269 14 283 

Female 217 164 53 217 

Total 500 433 67 500 

Table 3: Calculating the Chi-square statistic for the Frequency Distribution by Sex of the impact on inhabitants 

Health of oil Exploration activities 

Cells variables Fo Fe Fo-fe (fo-fe) 2 (Fo–Fe) 2 

Fe 

A 269 245.08 23.92 572.16 2.33 

B 14 37.92 -23.92 -572.16 -15.09 

C 164 187.92 -23.92 -572.16 -3.04 

D 53 29.08 23.92 572.16 19.67 

Total 

X 

500 500 3.87 

2 = (1) 3.87, P < .05 

The chi-square calculated using degree of freedom formula of (row- 1) (column –1) that is (2- 

1)(2-1) = 1, is, 3.87. This is written statistically as (x 2 = 3.91, d.f =1, < .05). This result is greater than 

the x 2 critical value of 3.84. Therefore this X 2 of 3.87 is significant. 

Table 4: Assessment by Occupation of Impact of oil multinationals on Health of inhabitants Observed 

frequencies in the Niger-Delta Region 

Occupation No Response Yes Pattern No Total 

Fishing 27 23 4 27 

Farming 33 29 4 33 

Trading 55 40 15 55 

Hunting 23 18 5 23 

Civil service 47 42 5 47 

Oil company 72 51 21 72 

Unemployed 210 210 - 210 

Business 33 26 57 33 

Total 500 439 61 500



Table 5: Calculating the Chi-Square Statistic for the Data Collected by Occupation 

Cells Fo Fe Fo-fe (fo-fe) 2 

(Fo − Fe) 

Fe 

A 23 23.71 -0.71 -0.50 0.02 

B 4 3.29 3.51 12.32 25.14 

C 29 28.97 3.54 12.53 0.49 

D 4 4.03 3.51 12.32 25.14 

E 40 48.29 -5.56 30.91 0.68 

F 15 6.71 13.17 173.45 94.78 

G 18 20.19 2.20 43.84 0.31 

H 5 2.81 4.39 19.27 1.82 

I 42 11.73 4.39 1927 31.59 

J 5 5.73 4.39 19.27 31.59 

K 51 63.22 6.22 38.69 0.86 

L 21 2.78 18.44 340.03 132.82 

M 210 184.38 25.62 656.38 3.56 

N 0 25.62 0 0.00 0.00 

O 26 28.77 3.17 10.09 0.44 

P 7 4.03 6.15 37.82 44.50 

Total 500 500 361.46 

X 2 (7) = 361.46, P


This statement is a fact of the health conditions of the Niger-Delta people. Infact, among the 

peoples of this region of Nigeria, they have a belief that, “dirts don’t kill the Blackman”. This 

corroborates other studies (Jike, 2004, and Okaba 2005; Afolabi, 2005). 

Table II and III is an assessment of the impact of oil exploration on health of inhabitants of host 

communities. The data from 500 male and female participants was analysed using the inferential 

statistical technique of chi-square (X 2 ). The result (X 2 (1) = 3.87, P < .05) confirmed the study’s 

objective of negative impact on health conditions by the oil corporations’ exploration activities. This 

result supports (Benike, 2002; Ogege; 2002, and Atumah 2005) studies, in assessing the environmental 

impact of oil exploration activities. 

Situating this result in the global context of the expectations governing oil explorations by 

multinationals will be the best measure to standardized the degree of health degradation and 

deprivation the people of this region are suffering consistently since the first oil well was struck in the 

country. The basic globalized expectation backed by labour laws is that of social responsibility 

(Afolabi, 2005). Meaning this multinationals owe their host communities the responsibility of basic 

health conditions of effective sanitary practices, medical infrastructural development and infact 

economic or financial commitments. But with so much profits declared every year, for instance, in 

2005, (Finighan, 2006) reported that Shell Petroleum Development Company declared 42 billion 

dollars profit, Chevron declared 14 billion dollars profit. Meanwhile communities where these ‘golden 

egg’ is laid are impoverished and her people dying daily due to unbearable health conditions. So, 

where does these monies go to? The Finighan report on this matter is real and alive in the Niger-Delta 

region of Nigeria. 

Table IV and V is a furtherance of assessing the impact of the oil exploration activities on 

various occupations in the Niger-Delta. It is evaluating the impact on each occupations, even the 

unemployed, to know first hand, the hazardous health nature of these multinationals activities. The data 

generated was analysed using the chi-square (X 2 ) statistic. The result (X 2 (7) = 361.46, P < .05) 

revealed that the oil exploration activities negatively impacted on all the occupations. Worst hit are the 

unemployed (see table IV). Where all 210 unemployed questioned none responded that the oil 

multinationals has any good thing to offer. This corroborates these studies (Atumah, 2005 and Okaba, 

2005). 

Although, this study did not separate medical practitioners from civil servants, the researcher 

identified some during the distribution of the questionnaires. Their responses were not different from 

teachers, administrators, etc, in the civil service occupation. A profile of common diseases suffered in 

this region according to these medical practitioners contacted, included tuberculosis, leprosy, asthma 

and other respiratory and cardiovascular diseases. These are particularly susceptible to toxic effects. 

One nurse puts it this way: “We see them coughing, sneezing, and complaining of chest, breast and 

breathing problems. Because of poverty and lack of drugs, they use herbs and vile concoctions that kill 

them slowly”. 

Unfortunately, these Niger-Delta people do not have corresponding medical infrastructures to 

cater for them despite the huge wealth generated from their lands. In fact like Hart, (1975) inverse care 

law: 

The availability of good medical care tends to vary inversely with the need 

for it in the population served. This inverse care law operates more 

completely where medical care is most exposed to market forces and less 

to where such exposure is reduced. 

Igun, (1979) refers to this situation in the Niger-Delta region as ‘disease palaces’ meaning, 

monies generated from the oil rich but degraded and impoverished Niger-Delta villages are used by the 

federal and state governments, in collaboration with these oil multinationals like Shell, Chevron, 

Exxonmobile and Texaco, to build medical centers of excellence in cities where the rich and powerful 

resides.



Conclusion 

The findings of this study revealed that oil exploration activities of multinational oil corporations 

negatively impacted on the health conditions of the people of the Niger-Delta region. This finding 

corroborates earlier studies conducted by academics, non government organizations and the world 

Health organization. 

Therefore, the researcher recommends that multinational firms operating in this region should 

deliberately separate the government taxation from their social responsibility to their host communities 

and directly invest in the communities. The federal government of Nigeria has done well now to 

establish the federal environmental protection agency. But to make this effective and result oriented, 

they should adopt a model of health infrastructural development that is sustainable. 

References 

[1] Afolabi, B. (2005) Bayelsa Youths Dare Shell. Tell Magazine, January 24. 

[2] Agbo, A. (2006). Terror Escalates in Niger Delta. Tell Magazine, February 6. 

[3] Atumah, P. (2005) Health Neglect of Oil Producing Communities in Niger Delta of Nigeria. 

Unpublished B.Sc Project, Department of Sociology and Psychology, Delta State University. 

[4] Benike, J. (2002) How the Federal Government and the multinationals Underdeveloped Niger 

Delta. Warri: Cotigo Creative Publishers. 

[5] Finighan, A (2006) “Multinational Oil Corporations Declare Bumper Profits”. February 4. 

Cable News Network: World Business Today. 

[6] Hart, J.T. (1975) “The Inverse Care Law” In S.Cox and M. Mead (Eds): A Sociology of 

Medical Practice. London; Collar – Macmillan. 

[7] Igun, U.A. (1979) Stages in Health-Seeking: A descriptive Model. Social Science and Medicine 

13, A(4). 

[8] Jike, V.T. (2004) Environmental Degradation, Social Disequilibrium and the Dilemma of 

Sustainable development in the Niger Journal of Black Studies. Vol. 33 No. X. 

[9] Ogege, S.O. (2002) The Dynamics of Oil Exploration and Crisis in the Niger Delta. 

Unpublished M.Sc Thesis, Department of Sociology, University of Ibadan. 

[10] Okaba, B. (2005) Petroleum Industry and the Paradox of Rural Poverty in the Niger Delta. 

Benin City. Ethiope Publishing Corporation. 

[11] Okpowo, B. (2002) Protest of Niger Delta Women. Vanguard Newspaper, 17 August.


ISSN 1450-216X Vol.14 No.3 (2006), pp. 447-455 



Development of Organic Carbon Sequestration Models for 

Dipterocarpus Turbinatus, Acacia Auriculiformis and Eucalyptus 

Camaldulensis and their Potentiality 

Md. Shahadat Hossain 

Institute of Forestry and Environmental Sciences 

University of Chittagong, Chittagong-4331, Bangladesh 

Gouri Rani Banik 

Lecturer,Department of Biochemistry and Molecular Biology 

University of Chittagong, Chittagong-4331, Bangladeshs 

E-mail: gouribanik2003@yahoo.com 

Tel.: +88-01717091189; Fax: +88-031-726310 

Abstract 

The study was conducted in the Chittagong University campus lies between about 

22º27′30″ and 22º29′0″ North latitudes and 91º46′30″ and 91º47′45″ East longitudes. The 

aim of the dissertation was to estimate organic carbon stock in the different components 

and to establish organic carbon calculating model for the three prominent species of 

Bangladesh viz. Dipterocarpus turbinatus Gaertn f., Acacia auriculiformis A Cunn. ex 

Benth, and Eucalyptus camaldulensis Dehn. Random sampling was carried out in the field 

during data and sample collection, data and samples were collected from the field, dry 

biomass and organic carbon content was determined in the laboratory to obtain the desired 

results.Proportionate carbon accumulation was distributed as 61.84%, 72.34% and 68.94% 

in main bole, as 11.15%, 7.93%, and 11.28%, in primary branches, as 6.98%, 4.29%, and 

5.73%, in secondary branches, as 7.27%, 4.34%, and 4.81%, in leaves & twigs, and as 

12.76% 11.11% and 9.44% in roots of Dipterocarpus turbinatus, Acacia auriculiformis, 

and Eucalyptus camaldulensis respectively.Allometric model, Y = a + bX1 + cX2 (Where, 

Y = Total carbon stock (kg), X1 = Total height (m) and X2 = Diameter at Breast Height 

(cm) was found to be the best predictor of biomass organic carbon for all the three species 

because of highest coefficient of determination (r 2 ) and significance of regression 

P>0.01.The model using only diameter at breast height or height with linear relations 

produced relatively poor relationship between organic carbon stock and specific single 

value. Three carbon tables for the studied three species were also developed by using the 

best fit regression equations. Annual gross organic carbon accumulation rate was found as 

8.91 kg/tree/year and 8.91 tonne/ha/year in Acacia auriculiformis, 5.36 kg/tree/year and 

9.50 tonne/ha/year in Eucalyptus camaldulensis and 2.33 kg/tree/year and 3.04 

tonne/ha/year in Dipterocarpus turbinatus. The studied three species have good capacity to 

sequester organic carbon from the atmosphere. Fast growing exotic species has 

comparatively higher rate of organic carbon accumulation. So fast growing species can be 

recommended to plant to minimize adverse effect of carbon in the atmosphere.

Development of Organic Carbon Sequestration Models for Dipterocarpus Turbinatus, 

Acacia Auriculiformis and Eucalyptus Camaldulensis and their Potentialit 448 

Key words: Sequestration, Allometric model, Dipterocarpus turbinatus Gaertn f., Acacia 

auriculiformis A Cunn. and Eucalyptus camaldulensis Dehn. 

Introduction 

Global climate change is one of the burning issues of present time where carbon is acting the key role. 

The trapping and build-up of heat in the lower atmosphere near the planet’s surface. Some of the heat 

flowing back towards space from the Earth’s surface is absorbed by water vapour, carbon dioxide 

(CO2), methane (CH4), and other gases in the atmosphere. If the atmospheric concentrations of these 

gases rise, then theory predicts that the average temperature of the lower atmosphere will gradually 

increase. The greenhouse effect in part explains the temperature differences of Mars, Venus and Earth. 

(Gifford, 2000). Moreover there is growing local and international concern over the increase of carbon 

in the form of carbon dioxide (CO2) in the atmosphere over the last few decades. Forests play an 

important role in the carbon cycle, removing carbon dioxide from the atmosphere and storing it as 

carbon in plant material and soil. So creating forests can provide a relatively cost-effective way of 

carbon sink. Organic carbon sequestration potential varies from species to species. Generally fast 

growing exotic species can sequester more carbon than that of indigenous species. So to fulfil organic 

carbon sequestration objective it is also important to choose suitable species. The most accurate 

method for calculating the amount of carbon stored in a tree is to fell the tree, measure its total biomass 

and analyse all parts of the tree for carbon content. However, this is not a practical method for 

calculating carbon stored in whole forests. Allometric relationships, which relate an easy-to-measure 

tree variable such as stem diameter to carbon stored in the tree, total height to carbon stored in the tree 

and diameter at breast height and total height together to carbon stored in the tree, are some principal 

method for estimating carbon stocks of forest and woodland ecosystems. In this study, some 

relationships have been developed to calculate sequestered organic carbon for three species viz. 

Dipterocarpus turbinatus, Acacia auriculiformis and Eucalyptus camaldulensis in respect of total 

height, diameter at breast height and combination of these two. 


The study was conducted on three prominent species viz. (Dipterocarpus turbinatus, Acacia 

auriculiformis and Eucalyptus camaldulensis) growing vigorously in the Chittagong University 

campus. Random sampling was carried out for data and sample collection. Five sample plots of 10m x 

10m size were taken for each species. Total height and diameter at breast height (DBH) of each 

individual within the sample plots were measured with the help of Spigel Relaskop and measuring tape 

respectively. One representative individual from each sample plot was harvested and all components 

viz root, main bole, primary branch, secondary branch and leaves & twigs were separated. Weight of 

each component was taken with the help of a field balance. Samples from all components were 

collected for analysis. Samples from the harvested individuals were taken into an envelope and kept 

those at 60ºC temperature in the oven until two adjacent weights attain to a constant value. Thus 

moisture percentages were determined. The oven-dried samples were then grinded. Porcelain crucibles 

were washed with 6N HCL and distilled water and dried in an oven at 65ºc for 1 hour. Less than 1g 

amounts of samples were taken into pre-weight crucibles. The crucibles were taken inside the cool 

furnace. After adjustment of the furnace at 550ºc, heating was increased slowly and after reaching at 

550ºc, ignition was continued for 1 hour. The crucibles were cooled slowly keeping them inside the 

furnace. After cooling, the crucibles with ash were weighted and percentage of ash was calculated. 

Then organic carbon percentage was determined. Relationship was tested considering total organic 

carbon content (kg) and diameter at breast height (cm), total organic carbon content (kg) and total 

height (m) and total organic carbon content (kg) and diameter at breast height (cm) along with height 

(m) by using SPSS. The best fit model was accepted to estimate organic carbon of the respective

449 Md. Shahadat Hossain and Gouri Rani Banik 

species based on coefficient of determination (r 2 ) and level of significance (p). Organic carbon 

sequestration potentials of the studied species have been determined using sample data from the 

plantations. 

Results and discussion 

Organic carbon percentage of dry biomass found in different components of the studied species varies 

from component to component, i.e., all components viz. leaf, secondary branch, primary branch, main 

stem and root do not contain same percentage of organic carbon of their respective dry biomass. In 

case of Dipterocarpus turbinatus leaf component shows the highest (57.50%) and secondary branch 

component shows the lowest (53.13%) value of organic carbon percentage of their respective dry 

biomass. Total organic carbon percentage of other components according to their respective dry 

biomass is close to the maximum and minimum value. In case of Acacia auriculiformis leaf component 

shows the highest (57.42%) and main stem component shows the lowest (54.64%) value of organic 

carbon percentage of their respective dry biomass. Total organic carbon percentage of other 

components according to their respective dry biomass is very close to the maximum and minimum 

value. In case of Eucalyptus camaldulensis leaf component shows the highest (57.69%) and secondary 

branch component shows the lowest (55.45%) value of organic carbon percentage of their respective 

dry biomass. Total organic carbon percentage of other components according to their respective dry 

biomass is also very close to the maximum and minimum value. The study revealed that the leaf 

organic carbon percentage is higher for every studied species. Reason may be stated as organic carbon 

accumulation in the tree from the atmospheric carbon dioxide occurs in the leaf through photosynthesis 

process. The carbon content in trees considered as 50% of the dry biomass (IPCC, 1999; Brown, 1997). 

In the study carbon percentage for individual component is found above 50% for all studied species. 

Moreover leaf organic carbon percentage for every studied species is higher of which cause has been 

mentioned above. 

Table: Organic carbon percentage of dry biomass of different components 

Species 

Components organic carbon (%) of dry biomass 

Root Stem Pr.Br Sec.Br. Leaves &Twigs 

Dipterocarpus turbinatus 55.91 54.06 55.91 53.13 57.50 

Acacia auriculiformis 55.91 54.64 55.68 55.10 57.42 

Eucalyptus camaldulensis 56.14 56.03 55.56 55.45 57.69 

Proportionate organic carbon distribution of different components of the studied 

species 

Among the organic carbon percentage of different plant components of the studied three species stem 

organic carbon of Acacia auriculiformis is maximum (72.34% of total organic carbon) in compared to 

Dipterocarpus turbinatus (61.84% of total organic carbon) and Eucalyptus camaldulensis (68.94% of 

total organic carbon). In case of root organic carbon it is found that percentage organic carbon 

contribution to the total organic carbon of Dipterocarpus turbinatus (12.76% of the total organic 

carbon) and Acacia auriculiformis (11.11% of total organic carbon) is comparatively close to each 

other than that of Eucalyptus camaldulensis (9.44% of total organic carbon). Contribution to the total 

organic carbon of primary branch of Dipterocarpus turbinatus and Eucalyptus camaldulensis is almost 

same to each other (11.15% and 11.28% respectively). But in case of Acacia auriculiformis it is much 

lower in proportion (7.93% only). Organic carbon contribution of secondary branch to the total organic 

carbon is least in all the studied species. In case of Acacia auriculiformis and Eucalyptus 

camaldulensis secondary branch organic carbon percentage is near about same (4.29% and 4.51% of 

the total organic carbon). In Dipterocarpus turbinatus it is found 6.98% of the total organic 

carbon.Leaf organic carbon for a certain period is largely dependent upon the phenological behavior of



the trees. In Dipterocarpus turbinatus leaf organic carbon (7.27% of the total organic carbon) is 

comparatively higher than that of the Acacia auriculiformis (4.34% of the total organic carbon) and 

Eucalyptus camaldulensis (5.73% of the total organic carbon). Organic carbon percentage of different 

plant components are shown in ‘Figure 1’. 

Figure 1: Organic carbon percentage of different plant components. 

Different tree species has shown variation in proportionate carbon accumulation in different 

components of them (Figure 1.). Among the components main bole contributed higher carbon 

accumulation for the studies three species. 

100% 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

7.27 

6.98 

11.15 

61.84 

12.76 

Dipterocarpus 

turbinatus 

4.34 

4.29 

7.93 

72.34 

11.11 

Acacia 

auriculiformis 

Species 

Organic carbon percentage of different plant components. 

Relationship between diameter at breast height (cm) and Total organic carbon 

content (kg) of the growing trees 

The regression equation for Dipterocarpus turbinatus calculating total organic carbon content 

(kg/tree) was found Y= -10.219 +3.601X. Here Y-represents the total organic carbon content of tree 

and X represents the diameter at breast height (cm). From the equation it implies that the total organic 

carbon content is increased by 3.601 kg for per unit increase in Diameter at Breast height. The 

coefficient of determination (r 2 ) is 0.9629 and the relationship was significant at P>0.01 The regression 

equation for Acacia auriculiformis calculating total organic carbon content (kg/tree) was found Y= - 

59.204+8.487X. Here Y represents the total organic carbon content of tree and X represents the 

diameter at breast height (cm). The regression line is presented in the graph. From the equation it 

implies that the total organic carbon content is increased by 8.487 kg for per unit increase in diameter 

at breast height. The coefficient of determination (r 2 ) is 0.948 and the relationship was significant at 

P>0.01. The regression equation for Eucalyptus camaldulensis calculating total organic carbon content 

(kg/tree) was found Y= - 10.113 + 5.421X. Here Y represents the total organic carbon content of tree 

and X represents the diameter at breast height (cm). The regression line is presented in the graph 

(Figure 2). From the equation it implies that the total organic carbon content is increased by 5.421 kg 

for per unit increase in Diameter at Breast height. The coefficient of determination (r 2 ) is 0.889 and the 

relationship was significant at P>0.01 . 

5.73 

4.61 

11.29 

68.94 

9.44 

Eucalyptus 

camaldulensis 

Leaves&Twigs 

Sec.Branch 

Pr.Branch 

Bole


The similar trend of this result was found by (Kilawe et al., 2001) in Pinus patula and 

Eucalyptus saligna, Ravichandran and Balasubramanian, 2000 in Casuarina equisetifolia and Raja 

Walayat Hussain, 1989 in Acacia nilotica, Acacia albida, Acacia tortilis and Prosopis cineraria. 

Figure 2: Linear relationships between diameter at breast height (DBH) and Total organic carbon content of 

growing species. Here Figure a) Dipterocarpus turbinatus. Fig.b) Acacia auriculiformis and Fig. c) 

Eucalyptus camaldulensis. The value of coefficient of determination (R 2 ) is shown. 

Fig. a Fig. b Fig. c 

Rrgression equation for Calculating Carbon 

from DBH of Dipterocarpus turbinatus 

50 

0 

6 6.5 11.2 12.4 12.6 

DBH(c m) 

R 2 = 0.9629 

Regrassion equation for calculating carbon 

from DBH for Acacia auriculiformis 

80 

60 

40 

20 

0 

DBH (c m) 

12 12.5 15 16 17 

Relationship between Height (m) and total organic carbon content (kg) of the 

growing trees 

Dipterocarpus turbinatus 

The regression equation for calculating total organic carbon content (kg/tree) was found Y= -39.126 + 

5.925X. Here Y represents the total organic carbon content of tree and X represents the Height (m). 

From the equation it implies that the total organic carbon content is increased by 5.925 kg for per unit 

increase in height. The coefficient of determination (r 2 ) is 0.962 and the relationship was significant at 

P>0.01. The result showed a positive correlation between Height and total organic carbon content of 

the species (Figure 3). 

Acacia auriculiformis 

The regression equation for calculating total organic carbon content (kg/tree) was found Y= - 47.014 + 

6.745X. Here Y represents the total organic carbon content of tree and X represents the Height (m). 



P>0.01. 

Eucalyptus camaldulensis 


4.261X. Here Y represents the total organic carbon content of tree and X represents the height (m). 



P>0.01. 

In the present study the linear correlation between total height (m) and total organic carbon 

content (m) was found stronger in Dipterocarpus turbinatus, Acacia auriculiformis and Eucalyptus 

camaldulensis. This trend was found similar with the result of the study by Ravichandran and 

Balasubramanian, 2000 in Casuarina equisetifolia. The linear correlation between total height (m) and 

total organic carbon content was found stronger in Dipterocarpus turbinatus, Acacia auriculiformis. 

Though there is a positive relation between total height and total organic carbon in Eucalyptus 

camaldulensis, Artocarpus chaplasha, and Chickrassia tabularis but the correlation was not so strong. 

R 2 = 0.966 

Regression equation for calculating carbon from DBH 

for Eucalyptus camaldusensis 

Carbon(kg) 

80 

60 

40 

20 

0 

DBH (cm) 

7.2 7.5 11.5 12 12.2 

R 2 = 0.9672



Figure 3: Linear relationship between Height (m) and Total organic carbon content of growing species. Here 

figure a) Dipterocarpus turbinatus. Fig.b) Acacia auriculiformis and Fig. c) Eucalyptus 

camaldulensis. The value of coefficient of determination (r 2 ) is shown. 

Regression equation f or calculating 

carbon from height for Dipterocarpus 

turbinatus 

50 

40 

30 

20 

10 

0 

Fig. a Fig. b 

8 10 11 

Hei ght (m) 

12 13 

R 2 = 0.9629 

Fig. c 

Regression equation for calculating carbon from 

height for Eucalyptus camaldulensis 

80 

60 

40 

20 

0 

8.5 

Carbon (kg) 

8.6 12.5 14 16.1 

Regression equation f or calculating 

carbon from height for Acacia 

auriculiformis 

Relationship between total organic carbon (kg) and DBH (cm) along with total 

height (m). 

Dipterocarpus turbinatus 


2.403X1 + 2.302X2. Here Y represents the total organic carbon content (kg) of tree, X1 represents the 

height (m) and X2 represents the DBH (cm). From the equation it implies that the total organic carbon 

content is increased by 2.403 kg for per unit increase in height and 2.302 kg for per unit increase in 

DBH (cm). The coefficient of determination (r 2 ) is 0.973 and the relationship was significant at 

P>0.01. The result showed a strong positive correlation between Height along with DBH and total 

organic carbon content of the species. 

Acacia auriculiformis 

The regression equation for calculating total organic carbon content (kg/tree) was found Y= - 22.214 + 

3.620X1 + 2.779X2. Here Y represents the total organic carbon content (kg) of tree X1 represents the 

height (m) and X2 represents the DBH (cm). From the equation it implies that the total organic carbon 

content is increased by 3.602 kg for per unit increase in height and 2.779 kg per unit increase of DBH. 

The coefficient of determination (r 2 ) is 0.974 and the relationship was significant at P>0.01. The result 

showed a positive correlation between height along with DBH and total organic carbon content of the 

species. 

100 

50 

0 

12 12.5 15 16 17 

Hei ght (m) 

R 2 = 0.980 

R 2 = 0.966


Eucalyptus camaldulensis 

The regression equation for total was found organic carbon content (kg/tree) was found Y= -6.113 + 

3.363X1 + 2.142X2. Here Y represents the total organic carbon content (kg) of tree, X1 represents the 

height (m) and X2 represents the diameter at breast height (cm). From the equation it implies that the 

total organic carbon content is increased by 3.363 kg for per unit increase in height and 2.142 kg for 

per unit increase of DBH. The coefficient of determination (r 2 ) is 0.980 and the relationship was 

significant at P>0.01. The result showed a strong positive correlation between height along with DBH 

and total organic carbon content of the species. 

In the present study it was found that both DBH (cm) and height (m) relating to total organic 

carbon was produced higher coefficient of determination (r 2 ) for Dipterocarpus turbinatus (0.973) 

Acacia auriculiformis (0.974) and Eucalyptus camaldulensis (0.980) than equations considering 

individual parameter viz height or DBH. So the result revealed that both DBH and height is the best 

predictor of total organic carbon measurement. This trend was found similar with the result of the 

study by Chowdhury, 2005 for Acacia auriduliformis, (0.932) Acacia mangium (0.966), Artocarpus 

heterophyllus, (0.968) Gmelina arborea (0.956) and Lagerstroemia speciosa (0.996). 

Total organic carbon sequestration (tonne/ha/year) of the studied species 

Among the studied species it was found that annual organic carbon sequestration (tonne/ha/year) rate 

was maximum in case of Eucalyptus camaldulensis (9.50 tonne/ha/year) and minimum in case of 

Dipterocarpus turbinatus (3.04 tonne/ha/year). The rate of organic carbon sequestration of Acacia 

auriculiformis was found 8.91 tonne/ha/year. From the figure it is found that although D. turbinatus 

has a significant difference between organic carbon accumulation rate with that of A. auriculiformis 

and E. camaldulensis but there is no significant difference between organic carbon accumulation rate 

of A. auriculiformis and that of E. camaldulensis. 

As E. camaldulensis and A. auriculiformis are fast growing species, their annual biomass 

production rate is higher than that of D. turbinatus which ultimately results the higher amount of 

organic carbon per year in the former two species than that of latter one. 

Total number of individuals per hectares was found higher in E. camaldulensis than that of D. 

turbinatus and A. auriculiformis. As amount of biomass from which we calculate organic carbon is 

directly related to the growing stock, for E. camaldulensis organic carbon accumulation rate per 

hectare was found higher. For the same reason higher rate of organic carbon accumulation was found 

in A. auriculiformis than D. turbinatus . Another reason for higher rate of organic carbon accumulation 

rate for A, auriculiformis and E. camaldulensis studied plantation sites of these two species were 

comparatively lower aged. At the early stage of plantations biomass accumulation rate is higher (Pant, 

1990). As Organic carbon accumulation is related to biomass accumulation therefore higher the 

biomass accumulation rate, higher the carbon accumulation rate. Some results of previous study could 

be mentioned here to compare the present findings with previous outcomes. 

D. turbinatus plantation accumulated less amount of organic carbon (including biomass and 

soil carbon) annually compared to that of A. auriculiformis. The biomass carbon content was also 

found highest in A. auriculiformis (Karmakar 2002). 

Another similar result was found in the study conducted by Osman et al., 1992 considering 

above ground biomass of 4, 5 and 8 years old A. auriculiformis & Pinus caribaea, A. auriculiformis 

and D. turbinatus, respectively in the Chittagong University. 

A study was conducted to assess the carbon stock in the 11-years old Aphanamixis polystachya 

(1991) in Chittagong University campus and it was reported that on an average 239 tonne (i.e 139 /11 

= 21.73 tonne/ha/year) carbon was stored in the biomass of the trees per hectare (Miah et al., 2001). 

The total dry biomass produced in 38 years old Tectona grandis in Uttar Pradesh was 130 tonne/ha 

(Kaul et al., 1979). If the biomass is converted to biomass carbon content, it will be 65 tonne/ha i.e. is 

slightly less than the biomass carbon content in studied D. turbinatus plantation of 27 years old



plantation in Chittagong university campus. Total organic carbon accumulation (tonne/ha/year) of the 

studied species are shown in Figure 4. 

Figure 4: Total organic carbon accumulation (tonne/ha/year) of the studied species 

Sequestered organic carbon 

(tonne/ha/year) 

14 

12 

10 

8 

6 

4 

2 

0 

Organic carbon sequestration (tonne/ha/year) 

3.04 

Dipterocarpus 

turbinatus 

8.91 

9.50 

Acacia auriculiformis Eucalyptus 

camaldulensis 

Species 

Total organic carbon accumulation (tonne/ha/year) of the studied species 


The author is gratefull to Dr. Mohammad Shafiul Alam Director, Institute of forestry and 

Environmental Sciences, Chittagong University for giving permission and providing all necessary 

facilities.and also express his gratitude to Dr. Mohammad Kamal Hossain, Plantation co-coordinator 

Institute of Forestry and Environmental Sciences, University of Chittagong, for giving permission to 

utilize resource of plantation division.


References 

[1] IPCC, 1999. Climate change 1995: a report of the Intergovernmental Panel on Climate 

Change, Cambridge University Press, New York. 

[2] Karmakar, N. C. 2002. Study on Carbon Sequestration Potential of Five Dominant Tree Species 

in Bangladesh. M. Sc. Thesis. Institute of Forestry and environmental Sciences, University of 

Chittagong. 

[3] Kilawe, E. C., Lusambo, L. P., Katima, J. H. Y., Augustino, S., Swalehe, N. O., Yimo, B. L., 

and Luwagila, S. 2001. Above ground biomass equations for determination of carbon storage in 

plantation forests in Kilombero District, Morogoro- Tanzania. International Forestry Review, 3 

(4): 317-321. 

[4] Pant, M. M. 1990. Forest Resource Management, FAO, Rome, Italy. 

[5] Miah, M.D., 2001. Global warming and carbon trading: Bangladesh perspective. Journal of 

Forestry and Environment, 1(1): 69-75. 

[6] Osman, K.T., Haque, S.M.S. and Forkan, M. 1992. Above ground biomass and nutrient 

distribution in Acacia auriculiformis, Dipterocarpus turbinatus and Pinus caribaea plantation at 

Chittagong University Hills. Indian Journal of Forestry,15(3): 193-197. 

[7] Kaul, O. N., Sharma, D. C., Tandon, V. N., and Srivastava, P. B. L. 1979. Organic matter and 

plant nutrient in teak (Tectona grandis) plantation. Indian Forester, 105 (8): 573-582. 

[8] Gifford, R. (2000). Carbon Content of Woody Roots: Revised Analysis and a Comparison with 

Woody Shoot Components. National Carbon Accounting System Technical Report No. 7 

(Revision 1). Australian Greenhouse Office, Canberra.

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