Chaos. Nonlinear Dynamics

Bubbles live on in their offspring. A bursting bubble begets daughter versions of itself - which could influence everything from glass-making to atmospheric processes.

Supply networks, such as the blood vessels that bring nutrients to our cells, often show tree-like branching into ever-finer channels. Three papers in the 29 January Physical Review Letters explore the effects of different conditions on the size and structure of such networks.

David Broomhead, School of Mathematics, The University of Manchester. Systems biologists are interested in modelling chemical reactions in the intracellular environment, and to date much of what is done is based on the use of mass action kinetics to construct models of elementary reactions. Mass action kinetic models are based on a number assumptions which are not obviously valid in the intracellular environment. The cytoplasm is far from an ideal, isotropic wellmixed solution and often the concentrations of important chemical species are very small.

We introduce a minimal Agent Based Model which includes the following elements (first considered by Lux and Marchesi): - Fundamentalists (F: stabilizing tendency) - Chartists (C: destabilizing tendency) - Herding effect (tendency to follow the others) - Price behavior (analysis of the price time series according to F or C criteria) The novelty of our model is a substantial simplification and corresponding reduction of the number of parameters.