We develop a multi-group epidemic framework via virtual dispersal where the risk of infection is a function of the residence time and local environmental risk. This novel approach eliminates the need to define and measure contact rates that are used in the traditional multi-group epidemic models with heterogeneous mixing. We apply this approach to a general n-patch SIS model whose basic reprodu...

A mean residence time (MRT) is an important pharmacokinetic parameter. To the author's knowledge, however, a physiologically based structure of MRT (thereafter MRT structure) has not been published so far. Primarily this is because MRT structures cannot be identified by traditional pharmacokinetic methods used for the determination of MRT. Therefore, tools from the theory of linear dynamic syst...

Intercomparisons of hillslopes and catchments in different hydrogeomorphic settings are rare. Those comparison studies that have been completed have focused largely on bulk outflow and chemistry. Here, we present a new functional intercomparison of two well studied hillslopes: one in New Zealand at Maimai and one in Japan at Fudoji. Slope angle, slope length, soil depth, climate and vegetation ...

Social foraging is common and may provide benefits of safety and public information. Public information permits faster and more accurate estimates of patch resource densities, thus allowing more effective foraging. In this paper we report on two experiments with red knots Calidris canutus, socially foraging shorebirds that eat bivalves on intertidal mudflats. The first experiment was designed t...

Small bluegill sunfish, Lepomis macrochirus, foraging among patches in the laboratory did not search systematically within a patch; their intercapture intervals did not differ from a model of random prey encounter within a patch. Patch-residence time, number of prey eaten, and giving-up time (time between last prey capture and leaving the patch) were measured for bluegills foraging in two diffe...

Our laboratory is engaged in an ongoing analysis of a 103-compound data set containing reliable intravenous pharmacokinetic parameters in the rat, dog, monkey, and human, and we have previously reported our findings regarding extrapolation of clearance. In this article, we report on our findings regarding volume of distribution and mean residence time. Various allometric and nonallometric metho...

Food is heterogeneously distributed in nature, and understanding how animals search for and exploit food patches is a fundamental challenge in ecology. The classic marginal value theorem (MVT) formulates optimal patch residence time in response to patch quality. The MVT was generally proved in controlled animal experiments; however, owing to the technical difficulties in recording foraging beha...

Intraspecific brood parasitism and cooperative breeding can be considered extremes on a continuum of parental care investment by a secondary female that visits the nest of a primary female. However, we lack a theoretical framework that predicts exactly where a secondary female will fall along this continuum. In this paper I present a model that predicts the fraction of a nesting period during w...