4,641 research outputs found

    Dark spot, Spiral waves and the SW Sex behaviour: it is all about UX Ursae Majoris

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    We present an analysis of time-resolved, medium resolution optical spectroscopic observations of UX UMa in the blue (3920-5250 A) and red (6100-7200 A) wavelength ranges, that were obtained in April 1999 and March 2008 respectively. The observed characteristics of our spectra indicate that UX UMa has been in different states during those observations. The blue spectra are very complex. They are dominated by strong and broad single-peaked emission lines of hydrogen. The high-excitation lines of HeII 4686 and the Bowen blend are quite strong as well. All the lines consist of a mixture of absorption and emission components. Using Doppler tomography we have identified four distinct components of the system: the accretion disc, the secondary star, the bright spot from the gas stream/disc impact region, and the unique compact area of absorption in the accretion disc seen as a dark spot in the lower-left quadrant of the tomograms. In the red wavelength range, both the hydrogen (H_alpha) and neutral helium (HeI 6678 and HeI 7065) lines were observed in emission and both exhibited double-peaked profiles. Doppler tomography of these lines reveals spiral structure in the accretion disc, but in contrast to the blue wavelength range, there is no evidence for either the dark spot or the gas stream/disc impact region emission, while the emission from the secondary star is weak. During the observations in 1999, UX UMa showed many of the defining properties of the SW Sex stars. However, all these features almost completely disappeared in 2008. We have also estimated the radial velocity semi-amplitudes K_1 and K_2 and evaluated the system parameters of UX UMa. These estimates are inconsistent with previous values derived by means of analysis of WD eclipse features in the light curve in the different wavelength ranges.Comment: 16 pages, 9 figures, Accepted for publication by MNRA

    Practical monitoring of the clinical efficacy of sinquanon in patients on antibiotic therapy

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    For more than seven decades, antibiotics and chemotherapeutics have been used successfully to treat and prevent infectious diseases, extensively changing the prognosis of severe infections and helping to improve quality of life. In the last two decades, the key role of the intestinal microbiota (IM) in basic vital functions such as digestion, protection against pathogens, and maintenance of immune and metabolic homeostasis has been recognized. Antibiotics do not selectively attack pathogenic bacteria. They have an effect on the normal microflora and can lead to imbalance inside the body (dysbacteriosis) and the development of opportunistic infections. Taking a probiotic during antibiotic treatment is one of the approaches to prevent antibiotic-associated diarrhea and other adverse effects of antibiotics when their use is necessary. In the present practical monitoring we want to share our results from the application of Sinquanon® to neutralize the negative effect of antibiotic treatment on the microbiome

    Nanoparticles as a possible moderator for an ultracold neutron source

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    Ultracold and very cold neutrons (UCN and VCN) interact strongly with nanoparticles due to the similarity of their wavelengths and nanoparticles sizes. We analyze the hypothesis that this interaction can provide efficient cooling of neutrons by ultracold nanoparticles at certain experimental conditions, thus increasing the density of UCN by many orders of magnitude. The present analytical and numerical description of the problem is limited to the model of independent nanoparticles at zero temperature. Constraints of application of this model are discussed

    Integrable quadratic Hamiltonians on so(4) and so(3,1)

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    We investigate a special class of quadratic Hamiltonians on so(4) and so(3,1) and describe Hamiltonians that have additional polynomial integrals. One of the main results is a new integrable case with an integral of sixth degree.Comment: 16 page

    On a possibility of inelasticity partial coefficient K sub gamma determination in pi C and pi Pb interactions at 10 to the 14th power eV (experiment PAMIR 1)

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    The investigation of hadron-nuclear interactions in Pamir experiment is carried out by means of X-ray emulsion chambers of two types: carbon (C) and lead (Pb). While comparing the results from the chambers of both types it was found a discrepancy in n sub h and E sub h(1)R values. The observed discrepancy in C and Pb chambers is connected with the difference in values of effective coefficients of energy transfer to the soft component K sub eff for C and Pb chambers

    Could One Find Petroleum Using Neutrino Oscillations in Matter?

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    In neutrino physics, it is now widely believed that neutrino oscillations are influenced by the presence of matter, modifying the energy spectrum produced by a neutrino beam traversing the Earth. Here, we will discuss the reverse problem, i.e. what could be learned about the Earth's interior from a single neutrino baseline energy spectrum, especially about the Earth's mantle. We will use a statistical analysis with a low-energy neutrino beam under very optimistic assumptions. At the end, we will note that it is hard to find petroleum with such a method, though it is not too far away from technical feasibility.Comment: 6 pages, 4 figures, EPL LaTeX. Final version to be published in Europhys. Let
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