We focus first on early outbreak stages when stochastic effects dominate and show that epidemics tend to happen faster than deterministic calculations predict. If an outbreak is sufficiently large, stochastic effects are negligible and we modify the standard ordinary differential equation (ODE) model to accommodate age-of-infection effects. We avoid the use of partial differential equations AZD5582 in vivo which typically appear in related models. We introduce a “”memoryless”"

ODE system which approximates the true solutions. Finally, we analyze the transition from the stochastic to the deterministic phase. (C) 2009 Elsevier Ltd. All rights reserved.”
“Vision often dominates audition when attentive processes are involved (e.g., the ventriloquist effect), yet little is known about AZD6738 price the relative potential of the two modalities to initiate a “”break through of the unattended”". The present study was designed to systematically compare the capacity of task-irrelevant auditory and visual events to withdraw attention from the other modality. Sequences

of auditory and visual stimuli were presented with different amounts of temporal offset to determine the presence, strength, and time-course of attentional orienting and reorienting as well as their impact on task-related processing. One of the streams was task-relevant, while crossmodal distraction caused by unexpected events in the other stream was measured by impairments of behavioral task performance and by the N2, P3a, and reorienting negativity (RON) components of the event-related potential

(ERP). Unexpected events in the visual modality proved to be somewhat more salient than those in the auditory modality, yet crossmodal interference caused by auditory stimuli was more pronounced. The visual modality was relatively constrained in terms of a critical time-range within which distraction effects could be elicited, while the impact of auditory stimuli on task-related processing extended over a longer time-range. selleck chemicals llc These results are discussed in terms of functional differences between the auditory and visual modalities. Further applications of the new crossmodal protocol are deemed promising in view of the considerable size of the obtained distraction effects. (c) 2010 Elsevier Ltd. All rights reserved.”
“Intraguild predation (IGP) is a widespread ecological phenomenon in which two consumers that share a resource also engage in a predator-prey interaction. Theory on IGP predicts the occurrence of alternative stable states, but empirical evidence of such states is scarce. This raises the question of whether alternative states are a rare phenomenon that is unlikely to be observed in nature. Here we analyze a model in which the resource exhibits logistic or chemostat dynamics and consumers have saturating (Type II) functional responses.