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Biomedical subjects

V G Il'ichev

Publications and source records attributed to V G Il'ichev.

6 recordsLinked to original sources
PubMedDate not supplied

[Universal reserve constants and selection criteria in the periodically changing environment].

The authors analyse different approaches (geometrical and analytical) to investigate the dynamic of competing populations in changing environment. For the broad range of models a sufficient character of selection is determined: in changing environment one population excludes the others if its productivity is higher with some reserve. In competition models "everybody against everybody" there is a universal reserve constant that is not depended on the number of populations in community. In the models "everybody against one" reserve constant can increase without limits in increasing the number of competitors.

Algorithms↗
PubMedDate not supplied

[The economical and evolutionary aspects of the optimal catch of the fish population].

The natural interpretation of population value (internal cost) is used for the common mathematical problem of population exploitation. It is suggested that the population owner--the state--can use internal costs as a tax on fish caught by holders (fishermen). It turns out that such a tax outline make fisherman to establish an optimal long-term strategy of catch. Moreover, if there is several fishermen' the special tax, which makes them to be consistent with common cooperative strategy, can be worked out. According to the proposed hypothesis the changes in internal costs can be used as an adaptive response to the "demand and supply" deformation of the exploited population. The concept of "ecological-economical" niche (habitat + place of sale) was proposed to characterize the exploited population. Computer calculations revealed the specific variant of Gause principle: the co-existing of two similar populations is impossible within single "ecologic-economical" niche. On the contrary, exploited similar populations show co-existence while fish is sailed on different markets.

Animals↗
PubMedDate not supplied

[Parameters adaptation in the populations models].

Ecology-evolutionary models of low dimensions were developed on the basis of competitive selection criteria. Dynamics of variables (number of individuals) and the search of evolutionary-stable values of parameters (biological characterictics of populations) were monitored in the suggested models. If the environmental temperature is changing periodically, the average (a) and width (d) of temperature tolerance range appears to be the important parameters. By model experiments it was established that stable values of temperature (a), favorable for development of highly specialized algae (d is low) were close to minimum and maximum of temperature curve. And for the low specialized algae (d is high) this values were close to the average temperature of environment. In a similar manner, a set of evolutionally stable parameters (a, d) was established for either of the two interacted populations (competitors and "predator-prey"). The hypotheses concerning it's geometric structure and the process of coevolution is formulated.

Adaptation, Physiological↗
PubMedDate not supplied

[Evolutionary stability in the dynamics of populations having short reproduction periods].

A special class of models of competition (D-systems) were constructed in which the coefficients of population growth are periodic delta-functions. Effective methods for the analysis of the global dynamics of D-systems were proposed. In the framework of this model system, the problem of the existence of evolutionarily stable parameters, the periods of reproduction of populations in a variable medium, was studied. Using analytical methods and the data of computer-assisted experiments, open sets of evolutionarily stable parameters were found.

Animals↗