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The modern basic theoretical principles of population regulation in mammals are reviewed in this paper. Consistent with the most fruitful systemic approach, a population, as the object of study, can be understood by both investigating the dynamics of the parts of the system (individual organisms) and by examining the context of population system in more inclusive community and landscape systems whose part it is.

Terrestrial landscapes are increasingly subject to fragmentation as a result of both natural and anthropogenic influences. How animals respond to fragmentation in the real world is an important ecological issue. We provide a prospectus for research linking population dynamics of small mammals to community dynamics in patchy landscapes. Our studies in the north-eastern United States demonstrate the importance of patch quality to the population dynamics of white footed mice (Peromyscus leucopus) within oak forest patches. These studies also provide evidence for dispersal of mice from patches of high quality to neighbouring patches of lower quality when mouse densities are at or near a peak. We contrast two alternative models for characterizing such dispersal between patch types - the source

In this article we present the current state of seasonal reproduction in mammals, a phenomenon which is well known to ecologists and endocrinologists. Emphasis is placed on mechanisms of seasonal reproduction and ecological considerations, first of all concerning the Djungarian hamster (Phodopus sungorus) since its seasonal rhythms and especially its photoperiodic control, have been studied extensively.

This paper continues the research of a gas-dynamic duct of supersonic heterogeneous devices with the use of a mathematical model developed earlier. Analysis is performed using dimensionless criteria of acceleration/deceleration path. A new criterion was introduced: the ratio of those lengths. This helps to estimate how the nozzle length, cut depth, pressures and temperatures in the pre-chamber and after the shock wave influence the flux of kinetic energy of particles bombarding the target surface (without real calculation of their acceleration (deceleration)). This excludes the particles from process analysis.

The problem of initiation of transition from nucleate to film boiling regime is considered from two statements: stationary and dynamic ones. Analysis of stationary problem allowed determination of relationship between heat load and critical size of a film domain. According to investigation of development dynamics of boiling crisis, at local deterioration in heat transfer, there is some critical size of a film domain, which is determined by a heat load and duration of initiating action. Whereas, at a local temperature increase, the critical conditions are determined only by the amplitude of temperature perturbation and heat power.

Basing on the three-dimensional equations of convective heat and mass transfer the processes of the combustion of a high-ash coal-dust fuel have been modelled numerically in the regions of real geometry (the PK-39 furnace chamber of the Aksuy State Regional Electric Station (SRES)). The distributions of temperature and NO_x concentrations are given over the furnace chamber height. The computed results are compared with experimental data obtained at the SRES. An analysis shows that the modelling and experimental results are in a good agreement, and the distribution of the nitrogen oxides over the torch length and the level of their extension in the atmosphere are close to industrial ones.

The paper is of generalizing character and summarizes in some way the researching cycle devoted to the development of arc generators of the water-steam plasma. The critical analysis of various designs of the plasmatorches intended for water-steam plasma production and their abilities is presented. The main emphasis is put on the plasmatorches wherein the spatial stabilization of the electric arc is carried out with the aid of a steam vortex. The operation conditions for these plasmatorches are discussed in details, and the ways of their realization are offered.

The results of experimental investigations of temperature fields and Joule heating in hollow cathodes in vacuum plasmatorches have been considered. The characteristics of thermal fields on the hollow cathode inner surface have been obtained with the use of the solution of a two-dimensional inverse thermal task. It has been shown that the Joule heating of cathodes may be ignored at cathode thickness of δ > 2^.10^-3 m and discharge currents of (I/d1) < 10⁴ À/m. The role of re-emission processes and plasma pressure in the cathode cavity at parameter gradient formation over the cathode length has been elucidated.

Flow aerodynamics in a cavity of cylindrical electrode of the arc plasmatorch and its erosion were experimentally studied. Dependency between erosion peculiarities and arc current was found out. Criterion relationships, which provide maximal electrode efficiency, were obtained.

The paper presents results of numerical simulation for screening effect of charged dust particles that are generated above the electrode due to its sputtering by plasma flow. Two problems are solved sequentially: calculation of plasma parameters for a diverter of fusion reactor and simulation of nucleation of liquid droplets due to condensation of metal vapour (electrode material). A one-dimensional  hydrodynamic computer code TDF was used for calculation of plasma parameters: temperature, density, material and heat flux along the plasma flow (directed along the magnetic field lines). This simulation also takes into account electric thermal conductivity, ionization, recharging, atom excitation, and plasma recombination. Existence of charged metal droplets and neutral component of plasma due to plasma recombination on the surface was included into this model.  Plasma parameters calculated by TDF are the initial data for kinetic code TAG, which is a stochastic model of non-equilibrium fluctuation stage of metal vapour condensation – during this stage the distribution function of nuclei on their size is formed.