379 research outputs found

    Studying temporal variability of GRS1739-278 during the 2014 outburst

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    We report a discovery of low-frequency quasi periodic oscillation at 0.3-0.7 Hz in the power spectra of the accreting black hole GRS1739-278 in the hard-intermediate state during its 2014 outburst based on the NuSTAR{\it NuSTAR} and Swift/XRT data. The QPO frequency strongly evolved with the source flux during the NuSTAR observation. The source spectrum became softer with rising QPO frequency and simultaneous increasing of the power-law index and decreasing of the cut-off energy. In the power spectrum, a prominent harmonic is clearly seen together with the main QPO peak. The fluxes in the soft and the hard X-ray bands are coherent, however, the coherence drops for the energy bands separated by larger gaps. The phase-lags are generally positive (hard) in the 0.1-3 Hz frequency range, and negative below 0.1 Hz. The accretion disc inner radius estimated with the relativistic reflection spectral model appears to be Rin<7.3RgR_{\rm in} < 7.3 R_{\rm g}. In the framework of the relativistic precession model, in order to satisfy the constraints from the observed QPO frequency and the accretion disc truncation radius, a massive black hole with MBH100M_{\rm BH} \approx 100M_\odot is required.Comment: 15 pages, 12 figures; accepted for publication in MNRA

    Variability of the structure of winter microbial communities in Chelyabinsk lakes

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    Microorganisms form complex and dynamic communities that play a key role in the biogeochemical cycles of lakes. A high level of urbanization is currently a serious threat to bacterial communities and the ecosystem of freshwater bodies. To assess the contribution of anthropogenic load to variations in the structure of winter microbial communities in lakes, microorganisms of four water bodies of Chelyabinsk region were studied for the first time. We used cultural, chromatography-mass spectrometric, and modern methods of statistical data processing (particularly, multivariate exploratory analysis and canonical analysis of correspondences). The research showed that the composition of winter microbial communities in lakes Chebarkul’, Smolino, Pervoye, and Shershenevskoye Reservoir did not differ significantly between the main phyla of microorganisms. The dominant microorganisms were found to be of the Firmicutes phylum and Actinobacteria phylum. The structure of bacterial communities had special features depending on the characteristics of the water body and the sampling depths. Thus, in the lakes Smolino, Pervoye, and Shershenevskoye Reservoir, an important role was played by associations between microorganisms – indicators of fecal contamination: coliform bacteria and Enterococcus. On the contrary, in Chebarkul’ Lake, members of the genus Bacillus, which are natural bioremediators, formed stable winter associations. However, the differences between water bodies and sampling depths reflected 28.1% and 9.8% of the variability of the winter microbial communities, respectively. The largest contribution (about 60%) to the variability of the structure was made by intra-water processes, which determined the high heterogeneity of samples from different water areas. We assume that an important role in this variability was played by the high anthropogenic impact in a large industrial metropolis. In our opinion, this line of research is very promising for addressing key environmental issues

    The influence of the concentration of montmorillonite containing sorbent and pH of the culture medium on the antibiotic sensitivity of Escherichia coli, as well as the effect of ground on growth of Escherichia

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    The aim of this work was the comparative sensitivity test of E. coli to enrofloxacin and doxycycline and bactericidal action of montmorillonite containing sorbent and its combination with enrofloxacin, as well as the influence of the concentration of the enriched montmorillonite containing sorbent and pH of the culture medium on the antibiotic sensitivity of Escherichia coli. The sensitivity test of Escherichia coli to enrofloxacin, and the combination of enrofloxacin with sorbent was performd by the method of double serial dilutions of drugs in a liquid culture mediu

    NOE Effect of Sodium Dodecyl Sulfate in Monomeric and Micellar Systems by NMR Spectroscopy

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    This paper describes the particular nuclear Overhauser effect (NOE) of sodium dodecyl sulfate (SDS) in monomeric and micellar systems. Two-dimensional NOE spectroscopy nuclear magnetic resonance (NMR) spectra of SDS in solution with concentration lower and higher than critical micellar concentration were recorded. In the first case diagonal and cross-peaks have different signs, and the opposite one was in the second case. This paper discusses theoretical background of this effect and we supposed that particular NOE can be used for inspection of SDS micelle formation during NMR researches. As a rough estimate of micelles formation an approach based on the difference between the chemical shifts in the monomer and micellar form of SDS was used. © 2014 Springer-Verlag Wien

    Innovative solutions of improving efficiency in public management

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    The paper reflects the analyzing of current trends in the use of innovation, technical and technological potential of different countries in the context of optimizing the interaction of government and the public to stimulate the effectiveness of public management. As a result of correlation analysis, it has been proven that the basic factors, determining the effectiveness of the outlined management model, are the level of development of online services and the availability of the necessary information data infrastructure. Perspective for e-government lies in the ability to improve and adapt innovative tools to public management systems around the world by using the existing digital, research and technological potential of governments of different countries

    Study of the Fast X-Ray Transient XTE J1901+014 Based on INTEGRAL, RXTE and ROSAT Data

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    The source XTE J1901+014 discovered by the RXTE observatory during an intense outburst of hard radiation and classified as a fast X-ray transient is studied. The source's spectral characteristics in the quiescent state have been investigated for the first time both in the soft X-ray energy range (0.6-20 keV) based on ROSAT and RXTE data and in the hard energy range (>20 keV) based on INTEGRAL data. A timing analysis of the source's properties has revealed weak nonperiodic bursts of activity on time scales of several tens of seconds and two intense (\sim0.5-1 Crab) outbursts more than several hundred seconds in duration. Certain assumptions about the nature of the object under study are made.Comment: 19 pages, 7 figure

    Transient receptor potential Ankyrin 1: structure, function and ligands

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    The aim of this study is to search and generalize information about structural features and molecular determinants, mechanisms of activation, action and modulation of TRPA1 as a universal pain and inflammation sensor, as well as the nature of activators and antagonists of this target and their therapeutic potentia
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