title: Simple model for directed networks.
abstract: We study a model for directed networks based on the Watts-Stogatz model for small-world phenomena. We focus on some topological aspects of directed networks inspired in food web theory, namely, the fraction of basal and top nodes in the network and node level distributions. We argue that in directed networks basal nodes play an important role, collecting information or resources from the environment. We give analytical expressions for the fraction of basal and top nodes for the model, and study the node level distributions with numerical simulations.
authors.affiliation: Abdus Salam International Centre for Theoretical Physics, Trieste, Italy. morelli@ictp.trieste.it
authors.forename: Luis G
authors.initials: LG
authors.lastname: Morelli