Parasites often play an important role in modifying the physiology and behavior of their hosts and may, consequently, mediate the influence hosts have on other components of an ecological community. Along the northern Atlantic coast of North America, the dominant herbivorous snail Littorina littorea structures rocky intertidal communities through strong grazing pressure and is frequently parasi...

In the last years the physics community has devoted a strong effort to the study of social networks. The availability of large databases containing information on the collaborations between movie actors, scientists, etc. has allowed for many statistical properties of the networks to be characterized. These studies have revealed that some characteristics appear to be general for these kind of ne...

We review and compare recent approaches to community structure identification. Definitions of communities are revisited, as well as the recently proposed modularity measure. We then classify the various methods into link removal methods, agglomerative methods, methods based on optimising the modularity measure, spectral methods and others. Finally, the performance of the methods, as applied to ...

We compare recent approaches to community structure identification in terms of sensitivity and computational cost. The recently proposed modularity measure is revisited and the performance of the methods as applied to ad hoc networks with known community structure, is compared. We find that the most accurate methods tend to be more computationally expensive, and that both aspects need to be con...

Fundamental to the scientific method is the use of controls or control conditions against which results obtained under test conditions are compared. In field studies, all variables cannot be controlled and replicates cannot be randomly assigned to treatments, so an attempt is made to choose test and control conditions (often represented by different sites) that are as similar as possible; the v...