A Mean Field Competition

Response of typha latiffolia to cutting competition and glyphosate under field conditions

Phase transition in a mean-field model for sympatric speciation

We introduce an analytical model for population dynamics with intra-specific competition, mutation and assortative mating as basic ingredients. The set of equations that describes the time evolution of population size in a mean-field approximation may be decoupled. We find a phase transition leading to sympatric speciation as a parameter that quantifies competition strength is varied. This tran...

Cellular-dynamical mean-field theory of the competition between antiferromagnetism and d-wave superconductivity in the two- dimensional Hubbard model

Cellular dynamical mean field theory is used to study the competition of antiferromagnetism and d-wave superconductivity at zerotemperature in the two-dimensional Hubbard model. The outcome strongly depends on the value of the interaction. At strong coupling (UX8t) a first-order transition takes place as a function of doping between pure antiferromagnet and pure superconductor. At weakcoupling ...

Non-mean-field effects in systems with long-range forces in competition.

We investigate the canonical equilibrium of systems with long-range forces in competition. These forces create a modulation in the interaction potential and modulated phases appear at the system scale. The structure of these phases differentiate this system from monotonic potentials, where only the mean-field and disordered phases exist. With increasing temperature, the system switches from one...

Species interactions in a changing environment: elevated CO2 alters the ecological and potential evolutionary consequences of competition

Question: How will global changes impact the ecological and evolutionary outcomes of competition? Hypothesis: Global changes that alter resource availability, such as rising atmospheric carbon dioxide (CO2) concentrations, will alter the effects of competition on mean fitness and patterns of natural selection. Because species exhibit different growth responses to elevated CO2 and because differ...

انحصار و رقابت در صنعت بیمه

Competition has not been an easy task in the field of insurance. Despite the fact that in the recent decades there has been some regulatory changes, and regulators’ approach tends toward more competition and prudential regulation, the regulatory approach to insurance markets from around the world has led to engendering barriers for competition. In this paper, we shall try to examine various ele...