178 research outputs found

    Research of GIS-services applicability for solution of spatial analysis tasks

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    Experiments for working out the areas of applying various gis-services in the tasks of spatial analysis are discussed in this paper. Google Maps, Yandex Maps, Microsoft SQL Server are used as services of spatial analysis. All services have shown a comparable speed of analyzing the spatial data when carrying out elemental spatial requests (building up the buffer zone of a point object) as well as the preferences of Microsoft SQL Server in operating with more complicated spatial requests. When building up elemental spatial requests, internet-services show higher efficiency due to cliental data handling with JavaScript-subprograms. A weak point of public internet-services is an impossibility to handle data on a server side and a barren variety of spatial analysis functions. Microsoft SQL Server offers a large variety of functions needed for spatial analysis on the server side. The authors conclude that when solving practical problems, the capabilities of internet-services used in building up routes and completing other functions with spatial analysis with Microsoft SQL Server should be involved

    Elastic Spin Relaxation Processes in Semiconductor Quantum Dots

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    Electron spin decoherence caused by elastic spin-phonon processes is investigated comprehensively in a zero-dimensional environment. Specifically, a theoretical treatment is developed for the processes associated with the fluctuations in the phonon potential as well as in the electron procession frequency through the spin-orbit and hyperfine interactions in the semiconductor quantum dots. The analysis identifies the conditions (magnetic field, temperature, etc.) in which the elastic spin-phonon processes can dominate over the inelastic counterparts with the electron spin-flip transitions. Particularly, the calculation results illustrate the potential significance of an elastic decoherence mechanism originating from the intervalley transitions in semiconductor quantum dots with multiple equivalent energy minima (e.g., the X valleys in SiGe). The role of lattice anharmonicity and phonon decay in spin relaxation is also examined along with that of the local effective field fluctuations caused by the stochastic electronic transitions between the orbital states. Numerical estimations are provided for typical GaAs and Si-based quantum dots.Comment: 57 pages, 14 figure

    Charge Radii and Magnetic Polarizabilities of the Rho and K* Mesons in QCD String Theory

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    The effective action for light mesons in the external uniform static electromagnetic fields was obtained on the basis of QCD string theory. We imply that in the presence of light quarks the area law of the Wilson loop integral is valid. The approximation of the Nambu-Goto straight-line string is used to simplify the problem. The Coulomb-like short-range contribution which goes from one-gluon exchange is also neglected. We do not take into account spin-orbital and spin-spin interactions of quarks and observe the ρ\rho and KK^* mesons. The wave function of the meson ground state is the Airy function. Using the virial theorem we estimate the mean charge radii of mesons in terms of the string tension and the Airy function zero. On the basis of the perturbative theory, in the small external magnetic field we find the diamagnetic polarizabilities of ρ\rho and KK^* mesons: βρ=0.8×104fm3\beta_\rho =-0.8\times 10^{-4} {fm}^3, βK=0.57×104fm3\beta_{K^*}=-0.57\times 10^{-4} {fm}^3Comment: 22 pages, no figures, in LaTeX 2.09, typos correcte

    Исследование острой токсичности монокатионного производного хлорина е6 – перспективного фотосенсибилизатора для антимикробной и противоопухолевой фотодинамической терапии

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    In this experimental work the acute toxicity of a chemically modified derivative of the natural pigment chlorophyll a called monocationic chlorin e6, which is a promising photosensitizer (PS) for antimicrobial and antitumor photodynamic therapy, was studied using white rats. The advantages of the PS under investigation are an intense absorption in the long-wavelength region of the visible spectrum, a sufficiently high quantum yield of singlet oxygen generation, pronounced amphiphilic properties along with an appropriate solubility in water, and a high level of photocytotoxic- ity in relation to both malignant HeLa cells and antibiotic-resistant hospital strains of E. сoli bacteria., P. aerugenosa and others. It has been shown that the value of LD50 of the considered PS can be calculated as the value of 100 mg/kg. In the reproduced experimental model of acute toxicity, pathomorphological changes in the vital organs of laboratory animals indicate a pronounced vasopathic effect of the drug with the development of cerebral edema and respiratory distress syndrome, which have become the main signs of thanatogenesis.На белых крысах изучены особенности острой токсичности химически модифицированного производного природного пигмента хлорофилла а монокатионного хлорина e6 – перспективного фотосенсибилизатора (ФС) для антимикробной и противоопухолевой фотодинамической терапии. Преимуществами ФС являются интенсивное поглощение в длинноволновой области видимого спектра, достаточно высокий квантовый выход генерации синглетного кислорода, выраженные амфифильные свойства наряду с хорошей растворимостью в воде и высокий уровень фотоцитотоксичности в отношении как злокачественных клеток линии HeLa, так и антибиотикорезистентных госпитальных штаммов бактерий E. coli, P. Aerugenosa и других. Величина ЛД50 для монокатионного хлорина e6 составляет 100 мг/кг массы тела. В воспроизведенной экспериментальной модели острой токсичности патоморфологические изменения жизненно важных органов лабораторных животных свидетельствуют о выраженном вазопатическом действии препарата с развитием отека головного мозга и респираторного дистресс-синдрома, ставшими основными звеньями танатогенеза

    Final NOMAD results on nu_mu->nu_tau and nu_e->nu_tau oscillations including a new search for nu_tau appearance using hadronic tau decays

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    Results from the nu_tau appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic tau decays, significantly improving the overall sensitivity of the experiment to oscillations. The "blind analysis" of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. allowed region in the sin^2(2theta)-Delta m^2 plane which includes sin^2(2theta)<3.3 x 10^{-4} at large Delta m^2 and Delta m^2 < 0.7 eV^2/c^4 at sin^2(2theta)=1. The corresponding contour in the nu_e->nu_tau oscillation hypothesis results in sin^2(2theta)<1.5 x 10^{-2} at large Delta m^2 and Delta m^2 < 5.9 eV^2/c^4 at sin^2(2theta)=1. We also derive limits on effective couplings of the tau lepton to nu_mu or nu_e.Comment: 46 pages, 16 figures, Latex, to appear on Nucl. Phys.

    Search for nu(mu)-->nu(e) Oscillations in the NOMAD Experiment

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    We present the results of a search for nu(mu)-->nu(e) oscillations in the NOMAD experiment at CERN. The experiment looked for the appearance of nu(e) in a predominantly nu(mu) wide-band neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are delta m^2 < 0.4 eV^2 for maximal mixing and sin^2(2theta) < 1.4x10^{-3} for large delta m^2. This result excludes the LSND allowed region of oscillation parameters with delta m^2 > 10 eV^2.Comment: 19 pages, 8 figures. Submitted to Phys. Lett.

    A study of backward going pp and π\pi^{-} in νμCC\nu_{\mu}CC interactions with the NOMAD detector

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    Backward proton and π\pi^- production has been studied in νμCC\nu_{\mu}CC interactions with carbon nuclei. Detailed analyses of the momentum distributions, of the production rates, and of the general features of events with a backward going particle, have been carried out in order to understand the mechanism producing these particles. The backward proton data have been compared with the predictions of the reinteraction and the short range correlation models.Comment: 29 pages, 14 figures, submitted to Nucl. Phys.

    Трансарктика-2019: зимняя экспедиция в Северный Ледовитый океан на НЭС «Академик Трёшников»

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    Preliminary results of the Transarktika-2019 winter expedition in the Arctic Ocean on the R/V “Akademik Tryoshnikov” are presented. The expedition program included studies on meteorology, hydrology, hydrochemistry, hydrobiology, geology, geophysics and an extensive complex of ice measurements in the Northern Barents Sea from the drifting ice and from the ship. During the expedition, it was possible to complete a wide range of tasks. The data obtained comprise a unique material for a comprehensive study of the current state of the environmental conditions in the Barents Sea. This paper highlights the most significant preliminary results of multidisciplinary observations in various environments, which will be further comprehensively analyzed and published in separate thematic articles.Представлены предварительные результаты зимней экспедиции «Трансарктика-2019» в Северном Ледовитом океане на НЭС «Академик Трёшников». Программа экспедиции включала в себя исследования по метеорологии, гидрологии, гидрохимии, гидробиологии, геологии, геофизике и обширному комплексу измерений ледяного покрова в северной части Баренцева моря с дрейфующего льда и с борта судна. Во время экспедиции удалось выполнить широкий круг задач. Полученные данные представляют собой уникальный материал для всестороннего изучения текущего состояния условий окружающей среды в Баренцевом море. В статье обозначены наиболее значимые предварительные результаты междисциплинарных наблюдений в различных средах, которые в дальнейшем будут всесторонне проанализированы и опубликованы в отдельных тематических статьях
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