The concept of chaos in ecological populations is widely known for non-overlapping generations since the early theoretical works of May [1974, 1976], and successively applied to laboratory and field studies [Hassell et al., 1976]. A classical approach using very simple models consists of using...

The critical boundaries separating ordered from chaotic behavior in randomly wired S-state networks are calculated. These networks are a natural generalization of random Boolean net and are proposed as an extended approach to genetic regulatory systems, sets of cells in different states or...

The analysis of some species-rich, well-defined food webs shows that they display the so called Small World behavior shared by a number of disparate complex systems. The three systems analysed (Ythan estuary web, Silwood web and the Little Rock lake web) have different levels of taxonomic...

A detailed analysis of three species-rich ecosystem food webs has shown that they display scale-free distributions of connections. Such graphs of interaction are in fact shared by a number of biological and technological networks, which have been shown to display a very high homeostasis against...

Models of habitat fragmentation have mainly explored the effects on a few species ecologies or on a hierarchical community of competitors. These models reveal that, under different conditions, ecosystem response can underly sharp changes when some given thresholds are reached. Here we explore...

Zipf's law states that the frequency of a word is a power function of its rank. The exponent of the power is usually accepted to be close to (-)1. Great deviations between the predicted and real number of different words of a text, disagreements between the predicted and real exponent of the...

RNA viruses are known to replicate with extremely high mutation rates. These rates are actually close to the so-called error threshold. This threshold is in fact a critical point beyond which genetic information is lost through a second-order phase transition, which has been dubbed the ``error...

We introduce a simple mathematical model of regulation of division of labour in insect societies based on the notion of fixed response thresholds. Individuals with different thresholds respond differently to task-associated stimuli. Low-threshold individuals become involved at a lower level of...

The spatiotemporal behavior of the spread of influenza in France has been studied, and algebraic spatial correlations (with exponent ) spanning the whole territory have been found to be present as soon as the number of reported cases first starts to increase, about 15 to 25 weeks before the peak...

How infectious diseases spread in space within one cycle of an epidemic is an important question that has received considerable theoretical attention. There are, however, few empirical studies to support theoretical approaches, because data is scarce. Weekly reports obtained since 1984 from a...