On the problem of Lessepsian migrations of zooplanktonic organisms

The scientific evidence accumulated on the migrations that zooplankton make from the Red Sea to the Mediterranean through the Suez Canal was analyzed. A conclusion was reached that some of the zooplankton, e.g. copepods Pontellina plumata, Calocalanus pavoninus, Arietellus pavoninus, reported in the literature as immigrants from the Red Sea, may in fact come from the Atlantic. The assumption is based on the fact that these organisms occur both in the eastern and the western Mediterranean. They inhabit the Atlantic Ocean, the Gibraltar Strait and the adjoining seawater, but are absent from the Suez Canal.It can be presumed that some zooplankton species widespread in the world ocean entered the MediterraneanSea through the Gibraltar Strait and the Suez Canal

Zooplankton of the Black Sea and the Eastern Mediterranean: Similarities and dissimilarities

A synthesis of data on abundance and biomass of zooplankton in the Eastern Mediterranean (EMED) and the Black Sea shows major differences in the composition and structure of pelagic communities in the two basins. Few Mediterranean planktonic animals have invaded and acclimatised in the Black Sea. The great bulk of Black Sea species is represented by coastal inhabitants that spread throughout the whole basin. This process has been called “neritization” of the Black Sea fauna. Peculiarities in zooplankton assemblages of the Black Sea have been further strengthened over the last few decades due to increasing eutrophication and the massive invasion of the ctenophore Mnemiopsis leidyi. The relative contribution of copepods, cladocerans, chaetognaths, and appendicularians to total zooplankton biomass has notably decreased , whereas gelatinous groups (mainly represented by Mnemiopsis and Aurelia aurita) contributed up to 99% of total wet weight in 1995 in the Black Sea.The basic features of planktonic fauna in the Black Sea are mainly due do the geo-morphological characters of the basin and the limited exchanges with the EMED, that are confined to the surface-subsurface layers in the Dardanelles and Bosphorus Straits. However, the dramatic changes that recently occurred in the structure of zooplankton assemblages seem to have been caused by heavy anthropogenic impact on the pelagic system

Проблемы правовой защиты информации приватного характера в условиях развития научно-технического прогресса

The article concernes the reasons causing endangerment of civil privacy rights by the computer information accumulation and data processing of private character as well as an analyzation of the legal regulation issues in the personal activities on the computer processing of information.В статье изучены причины, порождающие угрозу праву граждан на неприкосновенность сферы частной жизни компьютерным сбором и обработкой информации приватного характера, а также проанализированы проблемы правового регулирования деятельности лиц, занимающихся обработкой компьютерной информации

Particle transport: model of non-stationary fluctuations

Particle dynamics in non-uniform magnetic field for a slab and a cylinder is presented. The presence of electric field with low frequency drift (LFD) and lower hybrid drift (LHD) waves is considered. Drift waves as the possible cause of an anomalous transport in plasma are used in calculations. Non-stationary fluctuations of the electrostatic field of the plasma waves are modeled. The stochastization of the particles is studied numerically

Time-optimal algorithms focused on the search for random pulsed-point sources

The article describes methods and algorithms related to the analysis of dynamically changing discrete random fields. Time-optimal strategies for the localization of pulsed-point sources having a random spatial distribution and indicating themselves by generating instant delta pulses at random times are proposed. An optimal strategy is a procedure that has a minimum (statistically) average localization time. The search is performed in accordance with the requirements for localization accuracy and is carried out by a system with one or several receiving devices. Along with the predetermined accuracy of localization of a random pulsed-point source, a significant complicating factor of the formulated problem is that the choice of the optimal search procedure is not limited to one-step algorithms that end at the moment of first pulse generation. Moreover, the article shows that even with relatively low requirements for localization accuracy, the time-optimal procedure consists of several steps, and the transition from one step to another occurs at the time of registration of the next pulse by the receiving system. In this case, the situation is acceptable when during the process of optimal search some of the generated pulses are not fixed by the receiving system. The parameters of the optimal search depending on the number of receiving devices and the required accuracy of localization are calculated and described in the paper.This work was supported in part by the Russian Foundation for Basic Research (projects no 18-51-00001 and 19-01-00128), and Ministry of Science and Higher Education of the Russian Federation (project no. № AAA-A17-117052410034-6)

X-ray emission and photoelectron spectroscopy studies of interaction of nanocrystalline TiN and TiB₂ after highpressure sintering

A few samples of nanocrystalline TiN–TiB₂ ceramics were synthesized by high-pressure (3.0 GPa) and high-temperature (t = 1300–1500°C) sintering a mixture of TiN and TiB₂ nanopowders (80 wt.% TiN and 20 wt.% TiB₂) and the microhardness of the samples was determined. Peculiarities of the chemical bonding of the TiN–TiB₂ ceramics possessing the highest microhardness among the samples under consideration, mainly 29.65 ± 0.90 GPa, were studied in the present work using the X-ray emission and photoelectron spectroscopy methods. The X-ray emission spectra reflecting the energy distribution of the valence electronic states of the constituents (the N Kα (N 2p-like states), B Kα (В 2p-like states), Ti Lα (valence Ti s,d-like states) and Ti Kβ₅ (Ti 4p-like states) bands) were measured for the mentioned ceramics and for the initial mixture of TiN and TiB₂ nanopowders. For the above substances the X-ray photoelectron core-level binding energies were evaluated as well. It has been established that, when synthesizing the nanocrystalline TiN–TiB₂ ceramics from the initial mixture of TiN and TiB₂ nanopowders, the half-widths of the X-ray emission Ti Lα and Ti Kβ₅ bands decrease by (0.5–0.6) ± 0.2 eV

Instabilities and Bifurcations of Nonlinear Impurity Modes

We study the structure and stability of nonlinear impurity modes in the discrete nonlinear Schr{\"o}dinger equation with a single on-site nonlinear impurity emphasizing the effects of interplay between discreteness, nonlinearity and disorder. We show how the interaction of a nonlinear localized mode (a discrete soliton or discrete breather) with a repulsive impurity generates a family of stationary states near the impurity site, as well as examine both theoretical and numerical criteria for the transition between different localized states via a cascade of bifurcations.Comment: 8 pages, 8 figures, Phys. Rev. E in pres

The Dependence of the Superconducting Transition Temperature of Organic Molecular Crystals on Intrinsically Non-Magnetic Disorder: a Signature of either Unconventional Superconductivity or Novel Local Magnetic Moment Formation

We give a theoretical analysis of published experimental studies of the effects of impurities and disorder on the superconducting transition temperature, T_c, of the organic molecular crystals kappa-ET_2X and beta-ET_2X (where ET is bis(ethylenedithio)tetrathiafulvalene and X is an anion eg I_3). The Abrikosov-Gorkov (AG) formula describes the suppression of T_c both by magnetic impurities in singlet superconductors, including s-wave superconductors and by non-magnetic impurities in a non-s-wave superconductor. We show that various sources of disorder lead to the suppression of T_c as described by the AG formula. This is confirmed by the excellent fit to the data, the fact that these materials are in the clean limit and the excellent agreement between the value of the interlayer hopping integral, t_perp, calculated from this fit and the value of t_perp found from angular-dependant magnetoresistance and quantum oscillation experiments. If the disorder is, as seems most likely, non-magnetic then the pairing state cannot be s-wave. We show that the cooling rate dependence of the magnetisation is inconsistent with paramagnetic impurities. Triplet pairing is ruled out by several experiments. If the disorder is non-magnetic then this implies that l>=2, in which case Occam's razor suggests that d-wave pairing is realised. Given the proximity of these materials to an antiferromagnetic Mott transition, it is possible that the disorder leads to the formation of local magnetic moments via some novel mechanism. Thus we conclude that either kappa-ET_2X and beta-ET_2X are d-wave superconductors or else they display a novel mechanism for the formation of localised moments. We suggest systematic experiments to differentiate between these scenarios.Comment: 18 pages, 5 figure

Measurement of the ttbar Production Cross Section in ppbar collisions at sqrt s = 1.96 TeV in the All Hadronic Decay Mode

We report a measurement of the ttbar production cross section using the CDF-II detector at the Fermilab Tevatron. The analysis is performed using 311 pb-1 of ppbar collisions at sqrt(s)=1.96 TeV. The data consist of events selected with six or more hadronic jets with additional kinematic requirements. At least one of these jets must be identified as a b-quark jet by the reconstruction of a secondary vertex. The cross section is measured to be sigma(tbart)=7.5+-2.1(stat.)+3.3-2.2(syst.)+0.5-0.4(lumi.) pb, which is consistent with the standard model prediction.Comment: By CDF collaboratio