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With the data obtained by hydrobiological monitoring of water objects of Don river for many years (1978-1988) calculation of rank distribution parameters and indexes of dominance for phytoplankton species abundance was conducted. The borders of investigated characteristics are calculated. They correspond to borders of ecological well-being - trouble conditions of phytoplankton communities. Ecologically tolerable levels for the core abiotic factors are found. Contribution of each of analyzed factors to a degree of ecological trouble is established.

We consider two possible computational methods of the interpretation of experimental data obtained by means of the magnetic force microscopy. These methods of macrospin distribution simulation and reconstruction can be used for research of magnetization reversal processes of nanodots in ordered 2D arrays of nanodots. New approaches to the development of high-performance superscale algorithms for parallel executing on a supercomputer clusters for solving direct and inverse task of the modeling of magnetic states, types of ordering, reversal processes of nanosystems with a collective behavior are proposed. The simulation results are consistent with experimental results.

The dynamics of coupled elements’ ensembles are investigated in the context of description of spatio-temporal processes in the myocardium. Basic element is map-based model constructed by simplification and reduction of Luo-Rudy model. In particular, capabilities of the model in replication of different regimes of cardiac activity are shown, including excitable and oscillatory regimes. The dynamics of 1D and 2D lattices of coupled oscillatory elements with a random distribution of individual frequencies are considered. Effects of cluster synchronization and transition to global synchronization by increasing of coupling strength are discussed. Impulse propagation in the chain of excitable cells has been observed. Analysis of 2D lattice of excitable elements with target and spiral waves have been made. The characteristics of the spiral wave has been analyzed in depending on the individual parameters of the map and coupling strength between elements of the lattice. A study of mixed ensembles consisting of excitable and oscillatory elements with a gradient changing of the properties have been made, including the task for description of normal and pathological activity of the sinoatrial node.

We study the centrally symmetric mathematical model of electrodiffusion. This model describes in particular the transport of the Li⁺ ions in certain electrochemical current sources. We demonstrate that the steady state solution of the considered model exists and is unique if the boundary values of the ion concentration and electric potential are given. This solution also proves to be the stable attractor of the time-dependent solutions with different initial value distributions.

This article describes an experience of LIT JINR team in application software packages adaptation for running in different grid environments. Peculiarities of the applications “gridification” depending on their possible launch modes and a type of the matching computational resources are given. The particular applications and grid environments which applications are adopted for are listed.

This paper presents a model mixture of probability distributions of signal and noise. Typically, when analyzing the data under conditions of uncertainty it is necessary to use nonparametric tests. However, such an analysis of nonstationary data in the presence of uncertainty on the mean of the distribution and its parameters may be ineffective. The model involves the implementation of a case of a priori non-parametric uncertainty in the processing of the signal at a time when the separation of signal and noise are related to different general population, is feasible.

On the basis of the MGD equations we consider 2D- and 3D- nonstationary problems about the evolution of perturbations in the lower atmosphere and the Earth’s ionosphere which are caused by the movement of large meteoroids along gently sloping paths of the entry with the simulation of their destruction by the momentary increase of the midship at the point of the pressure head maximum. According to the results of our numerical investigation we obtain and analyze the detailed spatial-temporal distributions of the main parameters of the plasma flows from which in particular a number of phenomena that are similar to those seen in the Chelyabinsk phenomenon follow.

Work is devoted to modeling instrumental errors of a laser beam diameter measurement using a method based on a lambertian transmissive screen. Super-Lorenz distribution was used as a model of the beam. To determine the effect of each parameter on the measurement error were performed computational experiments, results of which were approximated by analytic functions. There were obtained the errors depending on relative beam size, spatial non-uniformity of the transmission screen, lens distortion, physical vignetting, beam tilt, CCD spatial resolution, ADC resolution of a camera. There was shown that the error can be less then 1 %.

The Compact Muon Solenoid (CMS) is a high-performance general-purpose detector at the Large Hadron Collider (LHC) at CERN. A distributed data analysis system for processing and further analysis of CMS experimental data has been developed and this model foresees the obligatory usage of modern grid-technologies. The CMS Computing Model makes use of the hierarchy of computing centers (Tiers). The Joint Institute for Nuclear Research (JINR) takes an active part in the CMS experiment. In order to provide a proper computing infrastructure for the CMS experiment at JINR and for Russian institutes collaborating in CMS, Tier-1 center for the CMS experiment is constructing at JINR. The main tasks and services of the CMS Tier-1 at JINR are described. The status and perspectives of the Tier1 center for the CMS experiment at JINR are presented.

New numerical simulation technique to calculate electrical properties of rocks with two-phase “oil– water” saturation is proposed. This technique takes into account surface conductivity of electrical double layers at the contact between solid rock and aqueous solution inside pore space. The numerical simulation technique is based on acquiring of electrical potential distribution in high-resolution three-dimensional digital model of porous medium. The digital model incorporates the spatial geometry of pore channels and contains bulk and surface grid cells. Numerical simulation results demonstrate the importance of surface conductivity effects.