720 research outputs found

    Three-dimensional local anisotropy of velocity fluctuations in the solar wind

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    We analyse velocity fluctuations in the solar wind at magneto-fluid scales in two datasets, extracted from Wind data in the period 2005-2015, that are characterised by strong or weak expansion. Expansion affects measurements of anisotropy because it breaks axisymmetry around the mean magnetic field. Indeed, the small-scale three-dimensional local anisotropy of magnetic fluctuations ({\delta}B) as measured by structure functions (SF_B) is consistent with tube-like structures for strong expansion. When passing to weak expansion, structures become ribbon-like because of the flattening of SFB along one of the two perpendicular directions. The power-law index that is consistent with a spectral slope -5/3 for strong expansion now becomes closer to -3/2. This index is also characteristic of velocity fluctuations in the solar wind. We study velocity fluctuations ({\delta}V) to understand if the anisotropy of their structure functions (SF_V ) also changes with the strength of expansion and if the difference with the magnetic spectral index is washed out once anisotropy is accounted for. We find that SF_V is generally flatter than SF_B. When expansion passes from strong to weak, a further flattening of the perpendicular SF_V occurs and the small-scale anisotropy switches from tube-like to ribbon-like structures. These two types of anisotropy, common to SF_V and SF_B, are associated to distinct large-scale variance anisotropies of {\delta}B in the strong- and weak-expansion datasets. We conclude that SF_V shows anisotropic three-dimensional scaling similar to SF_B, with however systematic flatter scalings, reflecting the difference between global spectral slopes.Comment: accepted in MNRA

    VASA-induced cytoplasmic localization of CYTB-positive mitochondrial substance occurs by destructive and nondestructive mitochondrial effusion, respectively, in early and late spermatogenic cells of the Manila clam

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    To analyze the release of mitochondrial material, a process that is believed to be (i) induced by the VASA protein derived from germplasm granules, and (ii) which appears to play an important role during meiotic differentiation, the localization of the CYTB protein was studied in the process of spermatogenesis of the bivalve mollusk Ruditapes philippinarum (Manila clam). It was found that in early spermatogenic cells, such as spermatogonia and spermatocytes, the CYTB protein shows dispersion in the cytoplasm following the total disaggregation of VASA-invaded mitochondria, what is called here as \u201cdestructive mitochondrial effusion (DME).\u201d It was found that the mitochondria of the maturing sperm cells also uptake VASA. It is accompanied by extramitochondrial transmembrane localization of CYTB assuming mitochondrial content release without mitochondrion demolishing. This phenomenon is called here as \u201cnondestructive mitochondrial effusion (NDME).\u201d Thus, in the spermatogenesis of the Manila clam, two patterns of mitochondrial release, DME and NDME, were found, which function, respectively, in early spermatogenic cells and in maturing spermatozoa. Despite the morphological difference, it is assumed that both DME and NDME have a similar functional nature. In both cases, the intramitochondrial localization of VASA coincides with the extramitochondrial localization of the mitochondrial matrix

    НОВЫЕ ПЕРСПЕКТИВЫ ИСПОЛЬЗОВАНИЯ ГАММА-ГЛУТАМИЛ-ТРАНСПЕПТИДАЗЫ В ЭНЗИМОДИАГНОСТИКЕ

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    Gamma-glutamyltranspeptidase (GGTP), isolated from a variety of sources from microorganisms to mammals, including human blood and organs, has been studied sufficiently detailed, which allowed to take a fresh look at the role of this enzyme in cellular metabolism, the pathogenesis of several diseases and its application in clinical medicine. Evidences in favor of use of GGTP as reliable marker to forecast cardiovascular diseases, and complications of type 2 diabetes of a metabolic syndrome are accumulated. Гамма-глутамил-транспептидаза (ГГТП), выделенная из разных источников, от микроорганизмов до млекопитающих, включая кровь и органы человека, достаточно подробно изучена, что позволило по-новому взглянуть на роль этого фермента в клеточном метаболизме, патогенезе ряда заболеваний и применении его в клинической медицине. Накапливаются доказательства в пользу использования ГГТП как надежного маркера прогноза сердечно-сосудистых заболеваний, осложнений диабета 2-го типа, метаболического синдрома.

    Optical absorption in boron clusters B6_{6} and B6+_{6}^{+} : A first principles configuration interaction approach

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    The linear optical absorption spectra in neutral boron cluster B6_{6} and cationic B6+_{6}^{+} are calculated using a first principles correlated electron approach. The geometries of several low-lying isomers of these clusters were optimized at the coupled-cluster singles doubles (CCSD) level of theory. With these optimized ground-state geometries, excited states of different isomers were computed using the singles configuration-interaction (SCI) approach. The many body wavefunctions of various excited states have been analysed and the nature of optical excitation involved are found to be of collective, plasmonic type.Comment: 22 pages, 38 figures. An invited article submitted to European Physical Journal D. This work was presented in the International Symposium on Small Particles and Inorganic Clusters - XVI, held in Leuven, Belgiu

    Aromaticity in a Surface Deposited Cluster: Pd4_4 on TiO2_2 (110)

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    We report the presence of \sigma-aromaticity in a surface deposited cluster, Pd4_4 on TiO2_2 (110). In the gas phase, Pd4_4 adopts a tetrahedral structure. However, surface binding promotes a flat, \sigma-aromatic cluster. This is the first time aromaticity is found in surface deposited clusters. Systems of this type emerge as a promising class of catalyst, and so realization of aromaticity in them may help to rationalize their reactivity and catalytic properties, as a function of cluster size and composition.Comment: 4 pages, 3 figure

    Magnetic field turbulence in the solar wind at sub-ion scales: in situ observations and numerical simulations

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    We investigate the transition of the solar wind turbulent cascade from MHD to sub-ion range by means of a detail comparison between in situ observations and hybrid numerical simulations. In particular we focus on the properties of the magnetic field and its component anisotropy in Cluster measurements and hybrid 2D simulations. First, we address the angular distribution of wave-vectors in the kinetic range between ion and electron scales by studying the variance anisotropy of the magnetic field components. When taking into account the single-direction sampling performed by spacecraft in the solar wind, the main properties of the fluctuations observed in situ are also recovered in our numerical description. This result confirms that solar wind turbulence in the sub-ion range is characterized by a quasi-2D gyrotropic distribution of k-vectors around the mean field. We then consider the magnetic compressibility associated with the turbulent cascade and its evolution from large-MHD to sub-ion scales. The ratio of field-aligned to perpendicular fluctuations, typically low in the MHD inertial range, increases significantly when crossing ion scales and its value in the sub-ion range is a function of the total plasma beta only, as expected from theoretical predictions, with higher magnetic compressibility for higher beta. Moreover, we observe that this increase has a gradual trend from low to high beta values in the in situ data; this behaviour is well captured by the numerical simulations. The level of magnetic field compressibility that is observed in situ and in the simulations is in fairly good agreement with theoretical predictions, especially at high beta, suggesting that in the kinetic range explored the turbulence is supported by low-frequency and highly-oblique fluctuations in pressure balance, like kinetic Alfv\'en waves or other slowly evolving coherent structures.Comment: Manuscript submitted to Frontiers Astronomy and Space Sciences, Research Topic: Improving the Understanding of Kinetic Processes in Solar Wind and Magnetosphere: From CLUSTER to MM

    Effect of electric field on the photoluminescence of polymer-inorganic nanoparticles composites

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    We report on the effect of electric field on the photoluminescence, PL, from a composite consisting of a conjugated polymer mixed with zinc oxide nanoparticles. We have found that in the absence of electric field PL emission from the composite film has two maxima in the blue and green-yellow regions. Application of a voltage bias to planar gold electrodes suppresses the green-yellow emission and shifts the only PL emission maximum towards the blue region. Current-voltage characteristics of the polymer-nanoparticles composite exhibit the non-linear behavior typical of non-homogeneous polymer-inorganic structures. Generation of excited states in the composite structure implies the presence of several radiative recombination mechanisms including formation of polymer-nanoparticle complexes including exciplex states and charge transfer between the polymer and nanoparticle that can be controlled by an electric field.Comment: 5 pages, 5 figures. accepted for publication in Solid State Communication

    The Problems of the Replacement of Alternative Penalties Taking into Account the Implementation of International Standards: Case of Some Post-Soviet Countries

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    International standards for the treatment of convicts without isolation from society contain the world experience of humanism in the execution of punishments and the development of the correctional system of all the countries in the world, concerning Russia and the countries of the former Soviet Union, they are adopted and implemented relatively recently. Today not all international standards have found their consolidation in the sectoral legislation of Russia and the CIS and Baltic countries. The execution of punishments is one of the most detailed regulated processes from the point of view of international regulation, as for the classification of the state as democratic, largely affects the compliance of its sectoral legislation in the penitentiary sphere with international standards. The aim of the study is to determine the features of the procedure for the replacement of alternative penalties, taking into account the implementation of international standards in some post-Soviet countries.     Keywords: international standards; alternative punishments; court; Prosecutor’s office; replacement of punishments

    The methodology of a part lifetime calculation

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    Reducing mills in piece-reduction at the moment of capturing the pipe's front end and on the rear end exit are exposed to increased dynamic loads. However these processes at present time are not fully researched. The relevant problem is to decrease dynamic loads in the clamp engine, to increase reliability and durability of the clamp on the basis of the mill's production growth on the account of pauses decrease, rise of the production amount, and reducing in pipe costs. In the article the results of the study to define a part lifetime in the reducing mill stand have been presented. A part lifetime was calculated in month for more convenient comparison with the production data. The results have been hand over to JSC "PNTZ" for implantation. © 2020 IOP Publishing Ltd. All rights reserved
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