Social insects---ants, bees, termites and wasps---exhibit a collective problem-solving ability (Deneubourg and Goss, 1989; Bonabeau et al., 1997). In particular, several ant species are capable of selecting the shortest pathway, among a set of alternative pathways, from their nest to a food source...

Many complex systems can be described in terms of networks of interacting units. Recent studies have shown that a wide class of both natural and artificial nets display a surprisingly widespread feature: the presence of highly heterogeneous distributions of links, providing an extraordinary...

The topology of the proteome map revealed by recent large-scale hybridization methods has shown that the distribution of protein-protein interactions is highly heterogeneous, with many proteins having few links while a few of them are heavily connected. This particular topology is shared by...

The next step in the understanding of the genome organization, after the determination of complete sequences, involves proteomics. The proteome includes the whole set of protein-protein interactions, and two recent independent studies have shown that its topology displays a number of surprising...