Vol 488, No 4 (2019)

The paper is devoted to the problem that determines the typical characteristics of computing equipment associated with the amount of work needed to obtain a result at a given point in the computation domain. The use of grid methods is associated with the need for continuous processing and storage of data arrays determined by the number of grid elements, which is directly proportional to the performance of the systems used. We consider alternative approaches for the construction and justification of computational methods that are not focused on the grid structure of the approximations. The substantiation of the convergence of kinetic approximations to the solution of the Cauchy problem is obtained.

An inhomogeneous Kirhhoff plate composed from semi-infinite strip-waveguide and a compaсt resonator which is in contact with the Winkler foundation of small compliance, is considered. It is shown that for any ε > 0, it is possible to find the compliance coefficient O(ε ²) such that the described plate possesses the eigenvalue ε ⁴ embedded into continuous spectrum. This result is quite surprising because in an acoustic waveguide (the spectral Neumann problem for the Laplace operator) a small eigenvalue does not exist for any unsubstantial perturbation. A reason of this dissension is explained as well.

According to the experimental results, a comparison of sizes of child-droplets after micro-explosion of drop based on water and diesel has been made. Convective, conductive, or radiative heat exchange has been dominated. The temperature of the medium and the relative volume concentration of the flammable liquid have been varied in ranges: 100-450 °С, 10-90 vol. %. The ratios of the sizes of the formed drops to the initial ones have been established. The conditions, which make it possible to increase the total evaporation surface area of a liquid by tens of times, are shown.

The problem of modeling the attitude-control modes of small spacecraft with the use of electromagnetic systems, interacting with the Earth’s magnetic field is considered. A small spacecraft angular motion mathematical model is developed. A control law for magnetic attitude control system of small spacecraft is formulated. Results of satellite with magnetic attitude control system movement numerical modelling are presented.

New high-thermostable carboranylmethyl-containing diorganosiloxane polymers have been obtained by polycondensation of equimolar amounts of 1.7-bis[hydroxy(dimethyl)silylmethylene]-m-carborane with bis(dimethylamino)diorganosilanes. It was shown, that in the case of replacement of 24 to 33 mol. % of dimethylsiloxane units with methylphenylsiloxane or diphenylsiloxane units with bulk phenyl groups, only amorphous polymers are formed. The polymers are highly soluble in organic solvents and have high thermostability.

Ignition of Fe nanopowders of bulk density and its samples compacted to relative density of 0,3-0,5 was studied while they were heated in the air. The ignition temperature of the compacted samples does not depend on the heating rate and comprises 100-115 °C. The oxidation process includes the stages of inert heating, ignition, surface and filtration modes of the reaction and afterburning. The time of the active stages, i.e. ignition and filtration mode, depends on the sample density at the same heating terms. It allows one to develop storage methods of Fe nanopowders as compacts.

For the first time very low values (up to 0,706707) of the ratio ⁸⁷Sr/⁸⁶Sr were recorded in the biogenic carbonates of the Omolon massif (Northeast Asia) of the Capitanian age. These results are in good agreement with previously obtained data on limestones in Japan (Kani et al., 2013; 2018). In general, the strontium ratio curve constructed by us repeats the well-known world trend, differing by its somewhat underestimated (by an average of 0,000-0,0008) its values. The Capitanian strontium minimum can be associated with the entry into the ocean of significant amounts of lightweight femic strontium due to a sharp increase in paleospreading. The maximum values of the strontium ratio, obtained from the middle part of the Intomodesma evenicum bivalve Subzone are 0,706986, which corresponds to the upper part of the Wuchiapingian stage.

In the paper there are results of a recent study of the active faults in the Kerch’ Peninsula. There was compiled a Map of Active Faults - sources of the strong earthquakes occurred in Late Holocene. The map is a regional seismotectonic model of strong earthquake sources - detailed basis for a spatial prognosis of the seismic hazard. Results of the study show that the Kerch’ Peninsula demonstrates signs of the classical morphostructures, and a morphology of the modern peninsula contours is caused by the large active fault zones.

New age determinations of detrital zircons of sandstones augmented the possibilities of interpretation of their provenance. This interpretation is often restricted by a formal comparison of age-and-composition characteristics of detrital crystals with any very distant model objects. A different situation arises when the role of a source of a detritus is claimed by local objects. The analysis of SHRIMP and TIMS - datеs of zircons and U and Th concentrations in them, and also a comparison of histograms of primary zircons from Riphean volcanics and rocks of the Taratash complex on one hand and the detrital zircons from the sandstones of Vendian (Asha series) and Lower Riphean (Ai Formation) on the other, have shown that the age variations of sources and clastics are comparable in many aspects. It means that the age characteristics of primary zircons from the Riphean volcanics and rocks of the Taratash complex as sources of zircon clastics for the Riphean and Vendian sandstones in the Southern Urals are regulated by processes of resedimentation, though the influence of distant sources is not excluded.

The data of micromycetes’ species and strain specificity in the process of toxic elements extracting from multicomponent solutions were obtained as results of modal experiments. The results also indicate the capability of biogenic mineral formation in organic strata.

The seismic attributes of the basement in the Podvodnikov Basin (primarily its P-wave velocities (5.9-6.2 km/s), the V_P /V_S ratio (1.71), the characteristic diffraction features of reflections from the basement) indicate the continental origin of the basin and suggest that its tectonic evolution began at the pre-oceanic stage of geological history of the Arctic.

Based on the 39-year satellite observation data series (1978-2017), three main types of large-scale sea-ice drift field in the Arctic Ocean (AO), characteristic of the winter season, were identified. The types of atmospheric circulation that form the structure of the drift fields are identified, the mechanism of the effect of changes in the drift fields on the interannual variations in the ice cover of the AO is described.

It was shown previously that cyclo-prolylglycine, an endogenous neuropeptide, is a positive AMPA receptor modulator and is able to increase the content of BDNF in neurons. In the present work it was shown that cyclo-prolylglycine at a dose of 1 mg/kg with subchronic intraperitoneal administration reduces the time of animal immobility to passive control, from 167.6 to 83.6 s on the 12th day of the experiment using the model of learned helplessness in rats. That indicates the presence of antidepressant-like activity. The results of the study allow us to consider that cyclo-prolylglycine is a link in the physiological regulation of a depressive-like state.

A morphological and immunohistochemical study of 24 gums biopsies was conducted in 19 patients aged 35-60 years with a diagnosis of partial secondary edentulous, chronic generalized periodontitis of moderate and severe degree (14 patients), and also without pathological changes in the periodontal disease (5 patients), who underwent dental implantation. Immunohistochemical reactions with antibodies to Ki-67, VEGF, SMA were performed on serial paraffin sections. It has been established that chronic periodontitis is characterized by a higher proliferative activity of the epithelium, which reflects its hyperplastic changes, as well as a lower content of SMA positive cells and the practical absence of the formation of privascular couplings from SMA-positive cells that are associated in tissues with “growth zones”, which indirectly indicates reduced tissue regenerative capacity. Therefore, in the case of the operation of dental implantation requires additional treatment aimed at anti-inflammatory and pro-regenerative effects.

Influence of fish personality on infection rate is almost not studied. In the experiments on the young-of-the-year Oncorhynchus mykiss and cercariae of a trematode Diplostomum pseudospathaceum we tested the hypothesis that infection rate differs between more and less active (“bold” and “shy”) fish. Will individual differences in infection persist upon re-infection? Fish serve as a second intermediate host for this trematode. A positive correlation was found between the results of consecutive infections. Accumulation of parasites with successive infections leads to an aggregated distribution of D. pseudospathaceum among the hosts, affecting individual fitness and polymorphism in fish populations. Persistent individual differences in parasite burden among fish and, as a result, vulnerability for predators confirms the role of parasites as an important factor of natural selection.