The intrinsic length scales of a reaction diffusion system (Gierer-Meinhardt model) is varied by quasi-statically changing the diffusion constant of the activator and a transition from rolls to hexagon is detected. The transition is hysteretic or first order like. From stability analysis, we...

It is generally believed that sustained directed transport in mechanical systems is not achievable under equilibrium conditions. In this article, by analyzing a simple model, we will show that directed motion under equilibrium conditions can take place and is not inconsistent with conservation...

A model based on quantitative genetics for the coevolution of plants and their pollinators is proposed. The model is characterized by competition for resources and by a two-fold coupling between the two types of species: pollinators depend on plants for resources and plants on pollinators for...