Lorentzian distributions have been largely employed in statistical mechanics to obtain exact results for heterogeneous systems. Analytic continuation of these is impossible even slightly deformed due the divergence all moments (cumulants). We solved this problem by introducing a ``pseudocumulants'' expansion. This allows us develop reduction methodology spiking neural networks subject extrinsic...

We consider the problem of explaining the emergence and evolution of cooperation in dynamic network-structured populations. Building on seminal work by Poncela et al., which shows how cooperation (in one-shot prisoner's dilemma) is supported in growing populations by an evolutionary preferential attachment (EPA) model, we investigate the effect of fluctuations in the population size. We find th...

We consider a diffusion model with neutral alleles whose population size is fluctuating randomly. For this model, the effects of fluctuation of population size on the effective size are investigated. The effective size defined by the equilibrium average heterozygosity is larger than the harmonic mean of population size but smaller than the arithmetic mean of population size. To see explicitly t...

in this investigation an attempt has been made to study the species composition, distribution and seasonal fluctuation of acarine community (arachnida: acari) in two undisturbed and well-vegetated plots located within padmaja naidu himalayan zoolo-gical park, darjeeling, india. the study continued for three consecutive years (january to december 1999–2001) revealed the presence of 10 acarine ge...

First we deal with a brief introduction of the autotroph-herbivore model system along with deterministic analysis of local stability, bifurcation behavior, and persistence of the populations. The second part consists of the stochastic formulation of the model system to incorporate the effect of environmental fluctuation and then analysis of nonequilibrium fluctuation. Stochastic stability crite...

DY 10.1 Tue 9:30 ZEU 160 Fluctuation-Driven Shifts in Selection Regimes in Population Dynamics — •Yen Ting Lin1, Hyejin Kim2, and Charles Doering3 — 1Max Planck Institutes for the Physics of Complex Systems, Noetnitzer Str. 38, Dresden 01187 , Germany — 2Department of Mathematics, Michigan State University, East Lansing, MI 48824, USA — 3Department of Mathematics, University of Michigan, Ann Ar...

The Surface Brightness Fluctuation method has been shown to be a powerful distance indicator for dwarf elliptical galaxies to very low surface brightness levels. It is applicable to stellar systems that are out of reach for classical indicators requiring resolved stellar populations such as the tip magnitude of the red giant branch. I briefly discuss a few results from recent SBF studies of dEs...