Relation between the X-ray and Optical Luminosities in Binary Systems with Accreting Nonmagnetic White Dwarfs

We investigate the relation between the optical (g-band) and X-ray (0.5-10 keV) luminosities of accreting nonmagnetic white dwarfs. According to the present-day counts of the populations of star systems in our Galaxy, these systems have the highest space density among the close binary systems with white dwarfs. We show that the dependence of the optical luminosity of accreting white dwarfs on their X-ray luminosity forms a fairly narrow one-parameter curve. The typical half-width of this curve does not exceed 0.2-0.3 dex in optical and X-ray luminosities, which is essentially consistent with the amplitude of the aperiodic flux variability for these objects. At X-ray luminosities Lx~1e32 erg/sec or lower, the optical g-band luminosity of the accretion flow is shown to be related to its X-ray luminosity by a factor ~2-3. At even lower X-ray luminosities (Lx~1e30 erg/sec), the contribution from the photosphere of the white dwarf begins to dominate in the optical spectrum of the binary system and its optical brightness does not drop below Mg~13-14. Using the latter fact, we show that in current and planned X-ray sky surveys, the family of accreting nonmagnetic white dwarfs can be completely identified to the distance determined by the sensitivity of an optical sky survey in this region. For the Sloan Digital Sky Survey (SDSS) with a limiting sensitivity m_g~22.5, this distance is ~400-600 pcComment: 7 pages, 3 figures, published in Astronomy Letter

Variability of the structure of winter microbial communities in Chelyabinsk lakes

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

Spectral analysis of X-ray pulsars with the INTEGRAL observatory

We studied spectra for 34 accretion-powered X-ray and one millisecond pulsars that were within the field of view of the INTEGRAL observatory over two years (December 2002 - January 2005) of its in-orbit operation and that were detected by its instruments at a statistically significant level (>8 sigma in the energy range 18-60 keV). There are seven recently discovered objects of this class among the pulsars studied: 2RXP J130159.6-635806, IGR/AX J16320-4751, IGR J16358-4726, AX J163904-4642, IGR J16465-4507, SAX/IGR J18027-2017 and AX J1841.0-0535. We analyze the evolution of spectral parameters as a function of the intensity of the sources and compare these with the results of previous studies

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

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

Using high-chromium iron as material for production of the equipping components of mine shafts

This paper deals with service conditions of shaft equipment, in particular, inserts of sliding bearings for the purpose of increasing service life due to material substitution and wear resistance increase. As a new material high-chromium irons are offered. Studies are conducted on a microstructure and wear resistance of prototypes is measured. Experimental data are treated by methods of mathematical statistics which confirm reliability of results. The results obtained make it possible to suggest using high-chromium irons as the direct material to produce inserts of sliding bearings

Influence of repeated intravital extraction of eggs from sturgeon hybrids on their oogenesis under conditions of recirculation aquaculture system

Dynamics of cytomorphological characteristics of oocytes in ovaries is considered for two sturgeon hybrids: besters of the breed Burtlevskaya Huso huso (Linnaeus) x Acipenser ruthenus (Linnaeus) and the breed Aksayskaya Acipenser ruthenus x ( Huso huso x Acipenser ruthenus ) on the experimental data obtained under controlled conditions in the aquatic complex in Moscow (Russia) in 2010-2012. Methods of intravital eggs extraction, ultrasound diagnostics, biopsy with the probe, anesthesia and histological analysis are applied. Structure of membrane is similar for straight sturgeon species and hybrids, but the membrane thickness and the term of its emergence on certain maturity stage are somewhat different, so the eggs of bester could be distinguished by the oocyte membrane thickness. Mean interspawning interval for the hybrids in conditions of recirculation aquaculture system at water temperature 20-21 °C is determined as 10-12 months

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

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 ($\sim$0.5-1 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

Economic concept of food development of Russian market

At present, the Russian economy is developing in the conditions of imposed sanctions on high-tech means of production by foreign countries. In this situation, the development vector is the formation of import substitution policies and the solution of food safety issues for various types of food products that are strategically important for human life. Meeting the needs of the country's population with its own production is a priority for the development of the agrarian market, which makes it possible to develop the production agrarian sector, the processing and trade sphere, to create additional jobs, thereby improving the quality and standard of living of people.peer-reviewe