218 research outputs found

    Phylogenetic analysis indicates transitions from vegetative to sexual reproduction in the Lobaria retigera group (Lecanoromycetidae, Ascomycota)

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    Phylogenetic relationships among the hypothetical species pairs Lobaria kurokawae / L. retigera and L. pseudopulmonaria / L. isidiosa were investigated based on TLC techniques and the phylogenetic analysis of the internal transcribed spacers (ITS) nrDNA. Results of TLC demonstrate that L. retigera and L. kurokawae can be chemically distinguished from L. isidiosa and L. pseudopulmonaria by the absence of retigeranic acid. Parsimony analysis of 18 specimens shows two monophyletic clades - a L. retigera lineage and a L. isidiosa lineage—both including their apotheciate counterparts. Unlike the original hypothesis of species pairs, our study reveals transitions from isidiate morphs that have the potential to rarely form apothecia, towards apotheciate morphs that produce no vegetative propagule

    Деякі питання державного контролю за цінами на сільськогосподарську продукцію

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    Чабаненко М. М. Деякі питання державного контролю за цінами на сільськогосподарську продукцію / М. М. Чабаненко // Актуальні проблеми держави і права : зб. наук. пр. / редкол.: В. В. Завальнюк (голов. ред.) [та ін.]. – Одеса : Видавничий дім "Гельветика", 2017. – Вип. 78. – С. 180-185.Проаналізовано проблеми визначення форм, методів контрольної діяльності органів публічної адміністрації в Україні у сфері забезпечення державного контролю за цінами на сільськогосподарську продукцію.Некоторые вопросы государственного контроля за ценами на сельскохозяйственную продукцию. Анализируются проблемы определения форм, методов контрольной деятельности органов публичной администрации в Украине в сфере обеспечения государственного контроля за ценами на сельскохозяйственную продукцию.Some issues of state control over the agricultural products prices. The article analyzes the problem of determining the forms, methods of control of public administration in Ukraine in the sphere of ensuring the quality of agricultural products and state regulation of prices

    Influence of crystal anisotropy on the critical state stability and flux jumps dynamics in a single crystal of La(1.85)Sr(0.15)CuO(4)

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    We studied the critical state stability in a large cubic sample of a single crystalline La(1.85)Sr(0.15)CuO(4) for different sample orientations with respect to the external magnetic field as well as the dynamics of the flux jumps. It is shown that thermomagnetic avalanches develop in dynamic conditions characterized by significantly lower magnetic diffusivity than the thermal one. In this case, critical state stability depends strongly on cooling conditions. We compared predictions of the isothermal model and of the model for the weakly cooled sample with experimental results. In both models, the field of the first flux jump decreases with an increase of sweep rate of the external magnetic field. We also investigated the influence of external magnetic field on the dynamics of the following stages of the thermomagnetic avalanche. It is shown that the dynamics of the flux jumps is correlated with the magnetic diffusivity proportional to the flux flow resistivity.Comment: submitted to: Superconductor Science and Technology, 17 pages, 5 figure

    Transverse and secondary voltages in BSCCO single crystals

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    Multicontact configuration is one of the most powerful arrangements for electrical transport measurements applied to study vortex phase transition and vortex phase dimensionality in strongly anisotropic high-Tc superconducting materials. In this paper we present electrical transport measurements using a multiterminal configuration, which prove both the existence of guided vortex motion in BSCCO single crystals near the transition temperature and that secondary voltage in zero external magnetic field is induced by thermally activated vortex loop unbinding. The phase transition between the bound and unbound states of the vortex loops was found to be below the temperature where the phase coherence of the superconducting order parameter extends over the whole volume of the sample. We show experimentally that 3D/2D phase transition in vortex dimensionality is a length-scale-dependent layer decoupling process and takes place simultaneously with the 3D/2D phase transition in superconductivity at the same temperature.Comment: 8 pages, 5 figures, to be published in Physica

    Magnetic flux jumps in textured Bi2Sr2CaCu2O(8+d)

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    Magnetic flux jumps in textured Bi2Sr2CaCu2O(8+d) have been studied by means of magnetization measurements in the temperature range between 1.95 K and Tc, in an external magnetic field up to 9 T. Flux jumps were found in the temperature range 1.95 K - 6 K, with the external magnetic field parallel to the c axis of the investigated sample. The effect of sample history on magnetic flux jumping was studied and it was found to be well accounted for by the available theoretical models. The magnetic field sweep rate strongly influences the flux jumping and this effect was interpreted in terms of the influence of both flux creep and the thermal environment of the sample. Strong flux creep was found in the temperature and magnetic field range where flux jumps occur suggesting a relationship between the two. The heat exchange conditions between the sample and the experimental environment also influence the flux jumping behavior. Both these effects stabilize the sample against flux instabilities, and this stabilizing effect increases with decreasing magnetic field sweep rate. Demagnetizing effects are also shown to have a significant influence on flux jumping.Comment: 10 pages, 6 figures, RevTeX4, submitted to Phys. Rev.

    Past centuries industrial architecture renovation methods

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    The problems of exploitation of industrial territories located in big city centers and their impact on architectural and space urban composition have been investigated in the paper. The question of refurbishing former industrial territories to residential or social purposes has been examined. The examples of industrial territories use in other countries as well as in Kyiv and Kharkiv have been shown. The term loft has been defined in the article for industrial buildings converted to residential purpose by preserving industrial design elements or new buildings in an industrial style including those that combine residential function with professional or social

    Patterned Irradiation of YBa_2Cu_3O_(7-x) Thin Films

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    We present a new experiment on YBa_2Cu_3O_{7-x} (YBCO) thin films using spatially resolved heavy ion irradiation. Structures consisting of a periodic array of strong and weak pinning channels were created with the help of metal masks. The channels formed an angle of +/-45 Deg with respect to the symmetry axis of the photolithographically patterned structures. Investigations of the anisotropic transport properties of these structures were performed. We found striking resemblance to guided vortex motion as it was observed in YBCO single crystals containing an array of unidirected twin boundaries. The use of two additional test bridges allowed to determine in parallel the resistivities of the irradiated and unirradiated parts as well as the respective current-voltage characteristics. These measurements provided the input parameters for a numerical simulation of the potential distribution of the Hall patterning. In contrast to the unidirected twin boundaries in our experiment both strong and weak pinning regions are spatially extended. The interfaces between unirradiated and irradiated regions therefore form a Bose-glass contact. The experimentally observed magnetic field dependence of the transverse voltage vanishes faster than expected from the numerical simulation and we interpret this as a hydrodynamical interaction between a Bose-glass phase and a vortex liquid.Comment: 7 pages, 8 Eps figures included. Submitted to PR
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