2009 Annual Report Vol.37 - 中研院物理研究所 - Academia Sinica

statistical and computational physics (SCP), applications of SCP to problems in
physical, biological, and social sciences, sponsoring meetings in SCP, and promoting
education and research of SCP in developing countries. Recent results completed at
LSCP include (Chin-Kun Hu and Ming-Chya Wu): 1. Solved a puzzle about
finite-size corrections for the dimer model on N×∞ square lattice and calculated
finite-size scaling function for the dimer on the triangular lattice. 2. Found scaling and
universal behavior in transition to synchronous chaos with local-global interactions
and routes to synchronization for coupled map lattice on scale-free networks. 3.
Developed general algorithm and computer packages ARVO and CAVE to calculate
volume, surface area, and properties of cavities in macromolecules (e.g. protein, DNA,
RNA, etc). 4. Used GROMOS96 force field to simulate C-terminal β-hairpin of
protein G and found that the free energy landscape of the beta-hairpin is consistent
with a two-state behavior with a broad transition state. 5. Used Go-like model and
MD simulations to study unfolding and refolding of immunoglobulin domain I27 and
ubiquitin upon force quench and found that the dependence of the refolding time on
quenched force is consistent with that observed in experiments; predicted the
unfolding pathways. 6. Studied molecular models of biological evolution to obtain
related phase diagrams for very general fitness functions; studied asexual and diploid
models with general smooth fitness landscapes and recombination. 7. Proposed
temporal transfer entropy (TTE) to analyze causality between two time series and
used TTE to construct a scheme for chaotic communications. 8. Used replicators in a
fine-grained environment to establish a theory of polymorphism.. 9. We found that
velocity distribution of monomers in the system of non-equilibrium polymer chains
follows q-statistics. 10. We used phase statistics to classify human ventricular
fibrillation signals into three types and found that one of them is fatal.
(3). Biology-Inspired Physics
Biological organisms are likely the most complex and the least understood systems
that one can imagine, due to their intricate biochemical and physical interactions
among macromolecules. Because all biological processes operate in a thermal
environment, statistical physics is an indispensable tool in studying them.
Experimentally, we try to understand the rich dynamics in networks of excitable and
oscillatory systems. Such systems are the BZ reactions, neuronal networks, cardiac
tissues and slime mould. We are studying the pattern formation, synchronization and
effects of external stimuli on the dynamics of the system, specifically, the effects of
heterogeneities. Major achievements include 1) Discovery of the difference in firing
patterns in neuronal network with and without glia; 2) Understanding of the
synchronization of cardiac cells in the presence of fibroblast (Chi-Keung Chan).
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