purcc 2012 - University of the Pacific

Poster Session Abstracts
part of the DO TMDL Project. These nitrogen
species are important nutrients in phytoplankton
growth which is a principal oxygen-consuming
material in the Stockton’s DWSC as it dies and
decomposes. Additionally, ammonia can
consume oxygen as it is oxidized by bacteria.
Nitrogen can come from a variety of
anthropogenic sources such as commercial
fertilizers, animal manures, and point source
such as the Stockton Waste Water Treatment
Plant. Understanding the sources and fate of
different nitrogen species entering the SJR
Estuary is a necessary part of the estuary model
and solving the low dissolved oxygen problem.
A Tail of Two Monkeys: Dietary Choice
in Relation to Cranial and Dental
Evolution in the Red Howler Monkey and
Olive Baboon
Pryia Patel
Faculty Mentor: Dorothy Dechant
Monkeys, along with prosimians, apes and
humans, are classified in the Order Primates.
Members of this order share certain
characteristics while each species exhibits a
number of unique traits. The niche parameters of
two monkeys, the New World red howler
monkey (Alouatta seniculus) and the Old World
olive baboon (Papio anubis) are compared here,
with emphasis on cranial and dental anatomy.
Literature searches resulted in comparative
information of the ecology, life history,
behavior, diet, locomotion and anatomy of these
two species. Cranial and dental measurements
were taken to describe anatomical differences
resulting from adaptation to an arboreal niche
with leaf-eating diet (howler monkey) versus a
terrestrial niche with omnivorous diet (olive
baboon). The data compiled suggests that
dietary adaptation to folivory has produced a
comparatively smaller, arboreal monkey while
adaptation to omnivory has produced a larger,
terrestrial monkey.
Preferred Diet - Got Insects or Leaves?
Laura Tsu
Faculty Mentor: Dorothy Dechant
New World monkeys, found in Central and
South America, and Old World monkeys, found
in Africa and Asia, are both part of the Order
Primates, but they have been geographically
separated for 35 – 40 million years. Having
reached the same grade of evolution, they share
some of the same characteristics, but different
monkey species also have unique traits that make
them distinct. The New World Red-Backed
Squirrel monkey (Saimiri oerstedii) and the Old
World Black and White Colobus monkey
(Colobus guereza) are compared in this study,
portraying differences between monkeys of the
Cebid and Cercopithecid primate
families. Information from scientific journals and
books has been complied about each species’
ecology, life history, diet, locomotion, behavior
and anatomy. Measurements of the skull and
teeth were also gathered and compared, revealing
even further differences in anatomy. Data from
these different sources confirm that Saimiri
oerstedii is the smaller species, occupying an
arboreal, frugivorous and insectivorous niche in
Central America and Colobus guereza is larger,
occupying an arboreal, folivorous niche in
Africa.
Voice and Laryngeal Design: The Role of
Vocal Fold Architecture
Gracie Castillo
Faculty Mentor: Marcos Gridi-Papp
The vibration of vocal folds is a complex
phenomenon and it was first modeled with
reasonable predictive power in the 1970's. Like
mammals, frogs make sounds with a pair of
vocal folds, but these have a different geometry,
being highly concave upstream. Our previous
measurements in frog larynges indicate that at
the onset of sound, they function as reed-based
wind instruments, where maximum airflow
occurs at intermediate pressures. The purpose of
this study is to design artificial larynges to test
hypotheses and model aspects of sound
production in frogs. A computer-controlled
source of air was connected to a PVC pipe
holding a pair of latex vocal folds configured to
produce sound. Artificial laryngeal air pressure,
airflow and generated sounds were recorded in
an anechoic chamber. The vocal folds are
positioned in two ways: a) the membranes are
completely flat, or b) they have a thickened
medial edge that makes them become concave
upstream (like a parachute) as the driving air
pressure is increased. Preliminary data show that
with the reinforced medial edge, our artificial
vocal folds vibrate within an extended range of
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