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...

Why are some ecosystems so rich, but yet contain so many rare species? High species diversity, together with rarity, is a general trend in neotropical forests and coral reefs. But the origin of such diversity and the consequences of food web complexity in both species abundances and temporal...

Size distributions in some ecosystems follow a power (Zipf-) law behavior spanning up to two ten decades. A model for the origins of this scaling behavior is presented. The model shows that the intrinsic dynamics of the system leads to a power law distribution, , with , in agreement with field...

Words in human language interact within sentences in non-random ways, and allow humans to construct an astronomic variety of sentences from a limited number of discrete units. This construction process is extremely fast and robust. The coocurrence of words within sentences reflect language...

We explore patterns of trophic connections between species in the largest and highest-quality empirical food webs to date, introducing a new topological prop- erty called the degree distribution, defined as the frequency of species SL with L links. Non-trivial differences are shown in degree...

Recent theoretical studies and extensive data analyses have revealed a common feature displayed by biological, social and technological networks: the presence of small world patterns. Here we analyse this problem by using several graphs obtained from one of the most common technological systems:...

Biotic recoveries following mass extinctions are characterized by a process in which whole ecologies are reconstructed from low-diversity systems often characterized by opportunistic groups. The recovery process provides an unexpected window to ecosystem dynamics. In many aspects, recovery is...

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...

A new order parameter approximation to Random Boolean Networks (RBN) is introduced, based on the concept of Boolean derivative. A statistical argument involving an annealed approximation is used, allowing to measure the order parameter in terms of the statistical properties of a random matrix....