نتایج جستجو برای: population fluctuation

تعداد نتایج: 719135  

Journal: :Physica A: Statistical Mechanics and its Applications 2009

2003
L. L. GETZ

Social behavior of the prairie vole, Microtus ochrogaster, including monogamy, mate guarding, philopatry, communal nesting, and territoriality, evolved as an adaptation to habitats with low food prevalent in the original range of the species. These behaviors are associated with low population densities and low amplitudes of fluctuation characteristic of low food habitats. In particular, reprodu...

2007
Jeffrey L. Herfindal Joanna M. Rankin

Numerous studies of the brightest Cambridge pulsar, B1133+16, have revealed little order in its individual pulses, apart from a weak 30-odd-rotation-period fluctuation feature and that some 15 per cent of the star’s pulsars are ‘nulls’. New Arecibo observations confirm this fluctuation feature and that it modulates all the emission, not simply the ‘saddle’ region. By replacing each pulse with a...

2008
Takeshi Sugimori Hiroyuki Hyuga Yukio Saito

We propose a new mechanism for the achievment of homochirality in life without any autocatalytic production process. Our model consists of a spontaneous production together with a recycling cross inhibition in a closed system. It is shown that although the rate equations for this system predict no chiral symmetry breaking, the stochastic master equation predicts complete homochirality. This is ...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2010
M Khasin M I Dykman B Meerson

We consider optimal vaccination protocol where the vaccine is in short supply. In this case, the endemic state remains dynamically stable; disease extinction happens at random and requires a large fluctuation, which can come from the intrinsic randomness of the population dynamics. We show that vaccination can exponentially increase the disease extinction rate. For a time-periodic vaccination w...

Journal: :Proceedings. Biological sciences 2009
Blaine D Griffen John M Drake

Ecological theory suggests that several demographic factors influence metapopulation extinction risk, including synchrony in population size between subpopulations, metapopulation size and the magnitude of fluctuations in population size. Theoretically, each of these is influenced by the rate of migration between subpopulations. Here we report on an experiment where we manipulated migration rat...

2015
Susmita Roy Biman Bagchi

Clinical studies have indicated that in malignant surveillances fluctuations in the population of certain effector T-cell repertoire become suppressed. Motivated by such observations and in an attempt to quantify adaptive human response to pathogens, we define an immune response function (IMRF) in terms of mean square fluctuations of T-cell concentrations. We employ a recently developed kinetic...

2012
Mika Oki Taro Yamamoto

BACKGROUND It has been suggested that the probability of dengue epidemics could increase because of climate change. The probability of epidemics is most commonly evaluated by the basic reproductive number (R(0)), and in mosquito-borne diseases, mosquito density (the number of female mosquitoes per person [MPP]) is the critical determinant of the R(0) value. In dengue-endemic areas, 4 different ...

Journal: :Advances in Complex Systems 2009
Karol Wawrzyniak Wojciech Wislicki

Generalization of the minority game to more than one market is considered. At each time step every agent chooses one of its strategies and acts on the market related to this strategy. If the payoff function allows for strong fluctuation of utility then market occupancies become inhomogeneous with preference given to this market where the fluctuation occured first. There exists a critical size o...

Journal: :The Journal of chemical physics 2005
Chi Zhang R Stephen Berry

We derive the energy fluctuation Delta(2)E, and the time autocorrelation kappa(tau) and its Fourier transformation--the fluctuation spectra S(omega)--of the master-equation transition matrix. The contribution from each eigenmode of the transition matrix to these fluctuation quantities reveals the relevant importance of the individual mode in the relaxation processes. The time scales associated ...

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