In recent years researchers have investigated a growing number of weighted heterogeneous networks, where connections are not merely binary entities, but are proportional to the intensity or capacity of the connections among the various elements. Different degree centrality measures have been proposed for this kind of networks. In this work we propose weighted degree and strength centrality meas...

We show an artificial world where animals (humans) and animats (software agents) interact in a coevolutionary arms race. The two species each use adaptation schemes of their own. Learning through interaction with humans has been out of reach for evolutionary learning techniques because too many iterations are necessary. Our work demonstrates that the Internet is a new environment where this may...

Background Air pollution is a trigger for human mortality. Although studies of spontaneous animal disease can provide additional insights, the short-term effects of air pollution on mortality have never been studied in animal populations. Animal sentinels are less subject to concurrent exposures, bias due to confounding, and exposure misclassification than human populations. Therefore we invest...

The livestock sector globally is highly dynamic. In developing countries, it is evolving in response to rapidly increasing demand for livestock products. In developed countries, demand for livestock products is stagnating, while many production systems are increasing their efficiency and environmental sustainability. Historical changes in the demand for livestock products have been largely driv...

Central-place foragers, such as ants, beavers, and colonial seabirds, can act as biological conduits, subsidizing local communities with allochthonous resources. To explore the consequences of such biologically vectored resource redistribution, we draw on an example from cave ecology and develop a population-level model of central-place foraging based on the dispersal kernel framework. We explo...

This paper aims to describe the population dynamics and to evaluate the stock of the seabob-shrimp Xiphopenaeus kroyeri on the coast of Pernambuco. Sampling was carried out between August/2011 and July/2012 in Sirinhaém, southern coast of Pernambuco. A total of 1201 individuals were analyzed, 673 females and 528 males. Total length (Lt) of females varied from 4.5 to 13.5 cm while the Lt of male...