Acquired immunity is known to be a key modulator of the dynamics of many helminth parasites in domestic and human host populations, but its relative importance in natural populations is more controversial. A detailed long-term dataset on the gastrointestinal nematode Trichostrongylus retortaeformis in a wild population of European rabbits (Oryctolagus cuniculus) shows clear evidence of seasonal...

An accurate method of solution is developed for the Warner and McIntyre parameterization of non-orographic gravity-wave drag for the case of hydrostatic dynamics in the absence of rotation. The new scheme is sufficiently fast that it is suitable for operational use in a general circulation model. Multi-year climate runs of the Canadian Middle Atmosphere Model are performed using the new scheme,...

We simulated a sensor network that detects and tracks the release of harmful airborne contaminants in an urban environment. The simulation determines sensor placement in that environment. The effort required integration of models from computational fluid dynamics (CFDs), combinatorial optimization, and population mobility dynamics. These CFD models, coupled with population mobility models, faci...

the current state of whitefish population and their organisms have been investigated in subarctic lake chuna exposed to long-term air pollution from copper-nickel industry. both annual and long-term heavy metals and acid oxides loads on the lake have been determined. a qualitative assessment has been made for water and bottom sediments. the investigation results have been compared with those of...

Samples of phytobenthos were collected during three different seasons in 2005 along a linear transect of a lowland peat bog at various spatial scales (10 cm, 1 m, 10 m) to investigate the seasonal dynamics, diversity, and factors influencing the spatial patterns of microalgal communities. Non-metric multidimensional scaling (NMDS), similarity percentage (SIMPER) analyses, ANOSIM, Mantel tests a...

The seasonal dynamics of biological traits in a population of European bitterling Rhodeus amarus from a small river in central Europe (River Kyjovka, Czech Republic) were investigated from April 2007 to March 2008. The reproductive season lasted from early April to mid-June, with a peak in late April when > 50% of females possessed ripe eggs in their ovaries. The sex ratio was female-biased, wi...

Biological phenomena offer a rich diversity of problems that can be understood using mathematical techniques. Three key features common to many biological systems are temporal forcing, stochasticity and nonlinearity. Here, using simple disease models compared to data, we examine how these three factors interact to produce a range of complicated dynamics. The study of disease dynamics has been a...