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The aim of these notes is to illustrate, largely by way of examples, how standard ecological models can be put into an evolutionary perspective in order to gain insight in the role of natural selection in shaping life history characteristics. We limit ourselves to phenotypic evolution under clonal reproduction (that is, we simply ignore the importance of genes and sex). Another basic assumption is that mutation occurs on a time scale which is long relative to the time scale of convergence...
A computational framework for testing the effects of cytotoxic molecules, specific to a
given phase of the cell cycle, and vascular disrupting agents (VDAs) is presented. The
model is based on a cellular automaton to describe tumour cell states transitions from
proliferation to death. It is coupled with a model describing the tumour vasculature and
its adaptation to the blood rheological constraints when alterations are induced by VDAs
treatment....
A decision analytical model is presented and analysed to assess the effectiveness and
cost-effectiveness of routine vaccination against varicella and herpes-zoster, or
shingles. These diseases have as common aetiological agent the varicella-zoster virus
(VZV). Zoster can more likely occur in aged people with declining cell-mediated immunity.
The general concern is that universal varicella vaccination might lead to more cases of
zoster: with more...
We analyze a two species discrete predator-prey model in which the prey disperses between two patches of a heterogeneous environment with barriers and the mature predator disperses between the patches with no barrier. By using the discrete dynamical system generated by a monotone, concave maps for subcommunity of prey, we obtain the subcommunity of prey exists an equilibrium which attracts all positive solutions, and using the stability trichotomy results on the monotone and continuous operator,...
We analyze a two species discrete predator-prey model in
which the prey disperses between two patches of a heterogeneous environment
with barriers and the mature predator disperses between the
patches with
no barrier. By using the discrete dynamical system generated by a monotone, concave
maps for subcommunity of prey, we obtain the subcommunity of prey
exists an equilibrium which attracts all positive solutions, and
using the stability trichotomy results on the monotone and
continuous operator,...
Eucalyptus globulus Labill is one of the most important economic forest species in Portugal, occupying an area of 875.10³ ha in a total forest area of 3346.10³ ha (Tomé et al., 2007). The main goal of this study is to develop a dominant height growth model for Eucalyptus, applicable throughout the country, representing an improve of the curves that are part of the whole stand model existing in Portugal, the GLOBULUS model (Tomé et al., 2001). The dominant height growth model will be built on a biological...
In questo lavoro si considera un’equazione alle derivate parziali del primo ordine con una condizione sulla frontiera di tipo integrale. Si studia resistenza, l'unicità e il comportamento asintotico delle soluzioni.
This paper deals with a reaction-diffusion system modeling a free boundary problem of the predator-prey type with prey-taxis over a one-dimensional habitat. The free boundary represents the spreading front of the predator species. The global existence and uniqueness of classical solutions to this system are established by the contraction mapping principle. With an eye on the biological interpretations, numerical simulations are provided which give a real insight into the behavior of the free boundary...
The paper deals with the question of existence and properties of equilibrated distributions of individual characteristics in an infinite population. General game-theoretic methods are applied and special attention is focused on the case of fitness functions depending only on the distance of an individual characteristic from a reference point and from the mean characteristics. Iterative procedures leading to equilibrated distributions are also considered.
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