3,381 research outputs found

    On the detection of point sources in Planck LFI 70 GHz CMB maps based on cleaned K-map

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    We use the Planck LFI 70GHz data to further probe point source detection technique in the sky maps of the cosmic microwave background (CMB) radiation. The method developed by Tegmark et al. for foreground reduced maps and the Kolmogorov parameter as the descriptor are adopted for the analysis of Planck satellite CMB temperature data. Most of the detected points coincide with point sources already revealed by other methods. However, we have also found 9 source candidates for which still no counterparts are known.Comment: 11 pages, 3 figures, Accepted for publication in Modern Physics Letters A. arXiv admin note: substantial text overlap with arXiv:1206.712

    To the center of cold spot with Planck

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    The structure of the cold spot, of a non-Gaussian anomaly in the cosmic microwave background (CMB) sky first detected by Vielva et al. is studied using the data by Planck satellite. The obtained map of the degree of stochasticity (K-map) of CMB for the cold spot, reveals, most clearly in 100 GHz band, a shell-type structure with a center coinciding with the minima of the temperature distribution. The shell structure is non-Gaussian at a 4\sigma confidence level. Such behavior of the K-map supports the void nature of the cold spot. The applied method can be used for tracing voids that have no signatures in redshift surveys.Comment: A & A (in press), 4 pages, 5 figures; to match the published versio

    Excitation of nonlinear two-dimensional wake waves in radially-nonuniform plasma

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    It is shown that an undesirable curvature of the wave front of two-dimensional nonlinear wake wave excited in uniform plasma by a relativistic charged bunch or laser pulse may be compensated by radial change of the equilibrium plasma density.Comment: 6 pages, 4 figure

    Planck's confirmation of the M31 disk and halo rotation

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    Planck's data acquired during the first 15.4 months of observations towards both the disk and halo of the M31 galaxy are analyzed. We confirm the existence of a temperature asymmetry, previously detected by using the 7-year WMAP data, along the direction of the M31 rotation, therefore indicative of a Doppler-induced effect. The asymmetry extends up to about 10 degrees (about 130 kpc) from the M31 center. We also investigate the recent issue raised in Rubin and Loeb (2014) about the kinetic Sunyaev-Zeldovich effect from the diffuse hot gas in the Local Group, predicted to generate a hot spot of a few degrees size in the CMB maps in the direction of M31, where the free electron optical depth gets the maximum value. We also consider the issue whether in the opposite direction with respect to the M31 galaxy the same effect induces a minimum in temperature in the Planck's maps of the sky. We find that the Planck's data at 100 GHz show an effect even larger than that expected.Comment: 4 pages, 1 table, 2 figures, in press as a Letter in A&

    General principles of uncomplicated cystitis therapy during pregnancy

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    Urinary tract infections during pregnancy are associated with severe complications. Earlier initiation of antibiotic treatment for acute uncomplicated cystitis, reduces the various complications.Objective. To assess the effectiveness of fosfomycin in the treatment of acute uncomplicated cystitis during II and III trimester of pregnancy.Material and methods. The study included 74 pregnant women who had acute uncomplicated cystitis in II or III trimesters. All patients received fosfomycin trometamol 3.754 g (equivalent to 3 g fosfomycin) as antimicrobial therapy for acute uncomplicated cystitis. The drug was prescribed to 24 pregnant women in the II, and 50 in the III trimester of pregnancy.Results. After treatment with fosfomycin signs of acute cystitis gone in all patients. At the same time, regression of clinical symptoms was noted during the next days after therapy in 95.9% (n = 71) of cases. Repeated microbiological test of the middle portion of urine was performed 7 days after the end of antibiotic therapy. In 94.6% (n = 70) cases, total elimination of the pathogen was achieved. In 5.4% (n = 4) cases, there was a significant decrease of colonization Follow-up for three months showed the absence of recurrence of acute cystitis in all pregnant women who were included in the study.Conclusion. Fosfomycin is a highly effective drug in the treatment of uncomplicated cystitis during pregnancy

    Some Open Points in Nonextensive Statistical Mechanics

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    We present and discuss a list of some interesting points that are currently open in nonextensive statistical mechanics. Their analytical, numerical, experimental or observational advancement would naturally be very welcome.Comment: 30 pages including 6 figures. Invited paper to appear in the International Journal of Bifurcation and Chao

    Self-amplified Cherenkov radiation from a relativistic electron in a waveguide partially filled with a laminated material

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    The radiation from a relativistic electron uniformly moving along the axis of cylindrical waveguide filled with laminated material of finite length is investigated. Expressions for the spectral distribution of radiation passing throw the transverse section of waveguide at large distances from the laminated material are derived with no limitations on the amplitude and variation profile of the layered medium permittivity and permeability. Numerical results for layered material consisting of dielectric plates alternated with vacuum gaps are given. It is shown that at a special choice of problem parameters, Cherenkov radiation generated by the relativistic electron inside the plates is self-amplified. The visual explanation of this effect is given and a possible application is discussed.Comment: 8 pages, 4 figures,1 table, the paper is accepted for publication in the Journal of Physics: Conference Serie

    The power spectrum of the cosmic microwave background Kolmogorov maps: possible clue to correlation of voids

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    The power spectrum is obtained for the Kolmogorov stochasticity parameter map for WMAP's cosmic microwave background (CMB) radiation temperature datasets. The interest for CMB Kolmogorov map is that it can carry direct information about voids in the matter distribution, so that the correlations in the distribution of voids have to be reflected in the power spectrum. Although limited by the angular resolution of the WMAP, this analysis shows the possibility of acquiring this crucial information via CMB maps. Even the already obtained behavior, some of which is absent in the simulated maps, can influence the development of views on the void correlations at the large-scale web formation.Comment: A & A (Lett.) (accepted), 4 pages, 3 fig

    Kolmogorov cosmic microwave background sky

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    A new map of the sky representing the degree of randomness in the cosmic microwave background (CMB) temperature has been obtained. The map based on estimation of the Kolmogorov stochasticity parameter clearly distinguishes the contribution of the Galactic disk from the CMB and reveals regions of various degrees of randomness that can reflect the properties of inhomogeneities in the Universe. For example, among the high randomness regions is the southern non-Gaussian anomaly, the Cold Spot, with a stratification expected for the voids. Existence of its counterpart, a Northern Cold Spot with almost identical randomness properties among other low-temperature regions is revealed. By its informative power, Kolmogorov's map can be complementary to the CMB temperature and polarization sky maps.Comment: A & A (in press), to match the published version, 4 pages, 5 figs, 2 Table

    A weakly random Universe?

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    The cosmic microwave background (CMB) radiation is characterized by well-established scales, the 2.7 K temperature of the Planckian spectrum and the 10−510^{-5} amplitude of the temperature anisotropy. These features were instrumental in indicating the hot and equilibrium phases of the early history of the Universe and its large scale isotropy, respectively. We now reveal one more intrinsic scale in CMB properties. We introduce a method developed originally by Kolmogorov, that quantifies a degree of randomness (chaos) in a set of numbers, such as measurements of the CMB temperature in some region. Considering CMB as a composition of random and regular signals, we solve the inverse problem of recovering of their mutual fractions from the temperature sky maps. Deriving the empirical Kolmogorov's function in the Wilkinson Microwave Anisotropy Probe's maps, we obtain the fraction of the random signal to be about 20 per cent, i.e. the cosmological sky is a weakly random one. The paper is dedicated to the memory of Vladimir Arnold (1937-2010).Comment: 4 pages, 3 figs, A & A (Lett) in press; to match the published versio
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