We analyze the population dynamics of a broad class of tness functions that exhibit epochal evolution|a dynamical behavior, commonly observed in both natural and arti cial evolutionary processes, in which long periods of stasis in an evolving population are punctuated by sudden bursts of change. Our approach| statistical dynamics|combines methods from both statistical mechanics and dynamical sy...

Time-asymmetric behavior as embodied in the second law of thermodynamics is observed in individual macroscopic systems. It can be understood as arising naturally from time-symmetric microscopic laws when account is taken of a) the great disparity between microscopic and macroscopic scales, b) a low entropy state of the early universe, and c) the fact that what we observe is the behavior of syst...

A number of recent papers have studied the finite temperature properties of ferromagnetic quantum spin chains. At low temperatures, macroscopic observables can be fully described by two dimensionful parameters which characterize the ground state. A convenient choice for these is the ground-state magnetization density M 0 , and the ground-state spin stiffness rs . Then the macroscopic properties...

Proteins arising from the Slo family assemble into homotetramers to form functional large-conductance, Ca2+- and voltage-activated K+ channels, or BK channels. These channels are also found in association with accessory beta subunits, which modulate several aspects of channel gating and expression. Coexpression with either of two such subunits, beta2 or beta3b, confers time-dependent inactivati...

The Bhatnagar–Gross–Krook BGK model approximates the collision term of the Boltzmann equation by a single relaxation process from a nonequilibrium state to an equilibrium state. From the BGK model, the Navier–Stokes, Burnett, and Super-Burnett equations can be derived. However, the success of these derived macroscopic equations in the description of highly nonequilibrium flow is limited. In ord...

sarcocystis is an obligatory intracellular protozoan parasite which can infect humans and animals. sheep are intermediate hosts of four sarcocystis species: sarcocystis tenella, sarcocystis gigantea, sarcocystis arieticanis, and sarcocystis medusiformision. the purpose of the study was to determine the molecular identification of the macroscopic and microscopic cysts of sarcocystis in sheep. in...