230 research outputs found

    Influence of Rotation on Pulsar Radiation Characteristics

    Get PDF
    We present a relativistic model for pulsar radio emission by including the effect of rotation on coherent curvature radiation by bunches. We find that rotation broadens the width of leading component compared to the width of trailing component. We estimate the component widths in the average pulse profiles of about 24 pulsars, and find that 19 of them have a broader leading component. We explain this difference in the component widths by using the nested cone emission geometry. We estimate the effect of pulsar spin on the Stokes parameters, and find that the inclination between the rotation and magnetic axes can introduce an asymmetry in the circular polarization of the conal components. We analyze the single pulse polarization data of PSR B0329+54 at 606 MHz, and find that in its conal components, one sense of circular polarization dominates in the leading component while the other sense dominates in the trailing component. Our simulation shows that changing the sign of the impact parameter changes the sense of circular polarization as well as the swing of polarization angle.Comment: 20 pages, 4 Postscript figures, uses aastex.cls. Accepted for Publication in ApJ 200

    Overiew of existing solutions excitation H₀₁ wave in the circular waveguide

    Full text link
    В данной работе рассмотрены осесимметричная магнитная волна H₀₁ в круглом волноводе, особенности структуры ее поля, возможности применения аномальных свойств волны H₀₁ на практике, кратко рассмотрены существующие способы возбуждения волны Н₀₁ в круглом волноводе такие как: возбуждение с помощью противофазных элементов связи, возбуждение с помощью торцевых щелей связи между прямоугольным и круглым волноводами, преобразование типов волн посредством плавных переходов между волноводами с разными типами волн, возбуждение с помощью цилиндрической щелевой антенны, возбуждение за счет подключения прямоугольного волновода узкой стенкой на закороченный торец круглого волновода. Также рассмотрены пути для получения максимального коэффициента передачи и расширения рабочей полосы устройства возбуждения.In the article axisymmetric magnetic wave H₀₁ in the circular waveguide, features of its field structure, possible implementation of its anomalous characteristics in practical systems are considered. Also existent excitation devices, such as: excitation with antiphased coupling elements, excitation with the frontal slots between rectangular and circular waveguides, modes transformation using taper between waveguides with different modes, excitation using the cylindrical slot antenna, excitation with the rectangular waveguides narrow side on the short-circuited end of the circular waveguide are described. The ways of deriving a maximal coefficient of transmission and widening of the frequency band of the excitation device are proposed

    Nuclear Scissors Mode with Pairing

    Full text link
    The coupled dynamics of the scissors mode and the isovector giant quadrupole resonance are studied using a generalized Wigner function moments method taking into account pair correlations. Equations of motion for angular momentum, quadrupole moment and other relevant collective variables are derived on the basis of the time dependent Hartree-Fock-Bogoliubov equations. Analytical expressions for energy centroids and transitions probabilities are found for the harmonic oscillator model with the quadrupole-quadrupole residual interaction and monopole pairing force. Deformation dependences of energies and B(M1)B(M1) values are correctly reproduced. The inclusion of pair correlations leads to a drastic improvement in the description of qualitative and quantitative characteristics of the scissors mode.Comment: 36 pages, 5 figures, the results of calculation by another method and the section concerning currents are adde

    Does the wall thickness of the left atrial appendage and its isthmus depend on their macroscopic characteristics?

    Get PDF
    Knowledge in interrelations between gross anatomy of the left atrial appendage (LAA) and thickness of the walls of LAA and periauricular area enables decreasing operational risks in LAA ostium occluding and «Cox-Maze» surgery for atrial fibrillation. The aim of the study was to identify significant interrelations between the macroscopic characteristics of the LAA (size, shape, number of lobes) and the parameters of the wall thickness of the LAA and its isthmus. Material and methods. The study includes 50 heart specimens of patients died from non-cardiac diseases. We examined 60 anatomical sections from 30 hearts by means Olympus SZX2-ZB10 microscope, and histological slices from 20 hearts. Results. The layers of the LAA wall were thinner than those in the isthmus. The thickness of LAA walls did not show direct correlation with the external dimensions of LAA. We found inverse correlation (Rs = – 0.4, p < 0,05) between the thickness of the myocardium, endocardium and some external sizes of LAA. The wall thickness of «chicken wing», «cauliflower» and «arrowhead» was the same. The wall of single-lobe LAA was thinner than that of two-lobed LAA (p = 0.036). The LAA isthmus wall was thinner (p = 0.03) in hearts with «cauliflower» LAA compared to hearts with LAA resembled a «chicken wing». Differences in wall thickness in LAA of various shapes were due to the degree of subepicardial fatty tissue development. Intracardiac operations should be done with the utmost care in patients with «cauliflower» LAA and single-lobe LAA to avoid damage of the LAA and periauricular area. Conclusions. The research found clinically significant interrelations between the LAA wall thickness and the number of its lobes as well as between the LAA isthmus wall thickness and LAA shape variants

    Relativistic Heavy--Ion Collisions in the Dynamical String--Parton Model

    Get PDF
    We develop and extend the dynamical string parton model. This model, which is based on the salient features of QCD, uses classical Nambu-Got\=o strings with the endpoints identified as partons, an invariant string breaking model of the hadronization process, and interactions described as quark-quark interactions. In this work, the original model is extended to include a phenomenological quantization of the mass of the strings, an analytical technique for treating the incident nucleons as a distribution of string configurations determined by the experimentally measured structure function, the inclusion of the gluonic content of the nucleon through the introduction of purely gluonic strings, and the use of a hard parton-parton interaction taken from perturbative QCD combined with a phenomenological soft interaction. The limited number of parameters in the model are adjusted to e+ee^+e^- and pp --pp data. Utilizing these parameters, the first calculations of the model for pp --AA and AA--AA collisions are presented and found to be in reasonable agreement with a broad set of data.Comment: 26 pages of text with 23 Postscript figures placed in tex

    Optimization of neuropsychological rehabilitation of higher mental functions in junior schoolchildren with mild intellectual disability

    Get PDF
    The article studies the effectiveness of complex neuropsychological rehabilitative impact on the nonverbal and verbal higher mental functions (HMFs) in junior schoolchildren with mild intellectual disability (ID) in comparison with the impact exclusively on the verbal HMFs in the same category of children.В статье рассматривается эффективность нейропсихологического коррекционного воздействия на невербальные и вербальные высшие психические функции детей младшего школьного возраста с легкой степенью умственной отсталости

    Jean Pecquet (1622–1674). To the 400th anniversary of the birth

    Get PDF
    The article is dedicated to the 400th anniversary of the birth of the outstanding French anatomist, physician and philosopher Jean Pecquet (1622–1674). Pecquet’s biography is connected with the city of Dieppe, where the future scientist was born and got his primary education, and with Paris, where he made his main discoveries in anatomy. Throughout his life, Pecquet collaborated with many prominent scientists of that time (Jacques Mentel, Louis Gayant, Jean Riolan (the Younger)), including not only physicians and anatomists, but also physicists such as Blaise Pascal, Edme Mariotte, Marin Mersenne and Evangelista Torricelli. Pecquet’s most famous discovery is the chyle cictern, or cisterna chyli. The structure was named after of the scientist – “Pecquet’s reservoir (cistern)”. But more revolutionary discovery made by Pecquet is revealing and proving the fact that the lymphatic ducts flow into the superior vena cava indirectly through the venous angles and refuting the conventional opinion on the drainage of lymph into the liver. An important help in Pecquet’s anatomical research and experiments was his passion for the physical and mathematical sciences. In collaboration with Edme Marriott, Pecquet studied the structure of the eyeball and turned out to be more foresighted, because, unlike Marriott, he correctly understood the role of the retina in the functioning of the eye as an organ of vision. Pecquet was one of William Harvey’s supporters regarding his concept of blood circulation. He introduced cutting-edge at that moment technologies into the anatomy methodology, including animal experiments in vivo, and made a fateful contribution to the progress of anatomical science

    PARENTERAL VIRAL HEPATITISES IN THE IRKUTSK REGION

    Get PDF
    From all group of infectious pathology viral hepatitises, from which the most priority are the parenteral hepatitises B and С, are essential for health of mankind, also the Irkutsk region isn’t an exception. The aim of the study: to assess an epidemiological situation in sharp and chronic forms of the viral hepatitises B and С in the territory of the Irkutsk region for the long-term period. Materials and methods. The retrospective analysis of an epidemiological situation on viral hepatitises B and C in Russia, Siberian Federal District and in the Irkutsk region for 2008–2016 is carried out. Results. The expressed decrease in incidence of acute viral hepatitis B is noted, at a chronic form of this disease rates of decrease had less expressed character that can be connected with carrying out by mass vaccinal prevention. The carried-out ranged distribution of territories for all forms of viral hepatitis B and viral hepatitis C in the Irkutsk region has allowed to reveal territories of risk. Conclusion. Parenteral viral hepatitises (sharp and chronic forms) are widespread in the territory of the Irkutsk region. From 43 administrative territories of the area, 24 belong to unsuccessful on incidences from which five are to territories of high epidemiological risk: cities of Irkutsk, Angarsk and Ust-Ilimsk and also Katangsky and Shelekhovsky districts

    Reconstruction of recombination sites in genomic structures of the strains of genotype 6 of hepatitis C virus

    Get PDF
    The encoded portion of the complete genomes of 46 strains of the genotype 6 of hepatitis C virus through bioinformatics RDP programs complex group of 6 recombinants strains was identified, in which 7 recombination sites were fixed. Strains correspond to the three-recombinant HCV subtypes: 6a, 6b and 61. For each of the identified recombinant we defined parent strains from which they can be obtained. Three recombinants were obtained from parent strains of the same subtype (homologous inside subgenotypic recombination). For the remaining three recombinants parent strains were members of three different subtypes (between subgenotypic recombination).In one strain we identified a unique recombination site in a highly conservative NS3 gene. Most of the recombination sites occurred in the region of the structural genes C, E1 and E2, and in the area of non-structural genes NS5a and NS5b.In the recombinant strain DQ480518-6a two recombination site were identified. One site is located in the structural and nonstructural genes (E2 + NS1 + NS2), and a second one in non-structural region. Dimensions of recombination sites can vary from 86 to 1072 nucleotide bases. The study identified "hot spots" of recombination in the strains of genotype 6 of hepatitis C virus. The recombinants were found in the population of the three countries: the United States (from the serum of an immigrant), Hong Kong and China

    Review of scientific topics for Millimetron space observatory

    Full text link
    This paper describes outstanding issues in astrophysics and cosmology that can be solved by astronomical observations in a broad spectral range from far infrared to millimeter wavelengths. The discussed problems related to the formation of stars and planets, galaxies and the interstellar medium, studies of black holes and the development of the cosmological model can be addressed by the planned space observatory Millimetron (the "Spectr-M" project) equipped with a cooled 10-m mirror. Millimetron can operate both as a single-dish telescope and as a part of a space-ground interferometer with very long baseline.Comment: The translation of the original article in Physics Uspekhi http://ufn.ru/ru/articles/2014/12/c
    corecore