We revisit the non-bilinear incidence rate model proposed by Severo, in order to introduce a derived dynamical model taking into account the heterogeneities related to environment, immunity and genetics. The properties of that model can be better understood by the means of the population dynamics theory.

It is well understood that populations cannot grow without bound and that it is competition between individuals for resources which restricts growth. Despite centuries of interest, the question of how best to model density dependent population growth still has no definitive answer. We address this question here through a number of individual based models of populations expressed using the proce...

We present supplementary investigations referring to the model of an evolving population described in Physica A 252 (1998) 325 335. The population is composed of individuals characterised by their genetic strings, phenotypes and ages. We discuss the in uence of probabilities of survival of the individuals on the dynamics and phenotypic variability of the population. We show that constant surviv...

Massive amounts of observation data recorded by amateurs are available for butterfl ies, allowing scientists to study their population dynamics and response to environmental threats. They report serious declines in many rarer species leading to an overall loss in biodiversity. As these declines refl ect the impacts of land use change, climate change and pesticide use, they also provide an alarm...

We describe a continuous-time modelling framework for biological population dynamics that accounts for demographic noise. In the spirit of the methodology used by statistical physicists, transitions between the states of the system are caused by individual events while the dynamics are described in terms of the time-evolution of a probability density function. In general, the application of the...

New technologies for culturing and settling scleractinian coral larvae in the field are required to elucidate the role of recruitment in population dynamics and to provide options for reef rehabilitation. Natural multi-species aggregations of coral embryos, which frequently form slicks on the sea surface after large-scale annual spawnings, were identified as a potential resource for mass coral ...

done so in 1980–1984.3 Since the condom is widely available and does not require a visit to a provider, the rapid increase in its use at first intercourse suggests that young women and men may be relying less on family planning providers as their first source of protection against pregnancy. An analysis of 1982 NSFG data determined that 17% of sexually active women aged 15–24 in 1982 had visite...

The Iberian hare (Lepus granatensis Rosenhauert, 1856) is a widely distributed endemic species in the Iberian Peninsula. In order to improve our knowledge of its population dynamics, the relative abundance and population trends of the Iberian hare were studied in the autumns of 1995–2012 in a protected area (Doñana National Park) by spotlighting in two different habitats: marshland and ecotones.

D. RYAN NORRIS* 1 , PETER ARCESE† 1 , DAVID PREIKSHOT‡, DOUGLAS F. BERTRAM§ and T. KURT KYSER¶ * Department of Integrative Biology, University of Guelph, Guelph, ON, Canada N1G 2W1; † Centre for Applied Conservation Research, Department of Forest Sciences, 2424 Main Mall, University of British Columbia, Vancouver, BC, Canada V6T 1Z4; ‡ Aquatic Ecosystems Research Laboratory, Fisheries Center, 2...

1. This paper describes the effects of differences in food quantity and quality on selected life history traits of Ceriodaphnia pulchella. Animals were fed with four concentrations of two green algae, Scenedesmus obliquus and Chlamydomonas globosa, given separately as well as in a 1 : 1 mixture. 2. In most cases growth, reproduction and condition of the animals and consequently the rate of popu...