1,185 research outputs found

    Seismic coherence measure in presence of residual trace-to-trace time delay variations

    Get PDF
    В работе после сопоставительного анализа меры когерентности и предполагаемой модели сейсмической записи предложен новый метод оценки когерентности. Метод обеспечивает большую чувствительность когерентности в присутствии остаточных временных сдвигов после учета локального наклона в окне анализа. Он основан на более реалистичной модели сейсмической записи, которая допускает произвольные вариации амплитуды сигнала, дисперсии помехи и остаточных временных сдвигов. Новый метод апробирован на теоретических и реальных данных.В роботі після порівнювального аналізу міри когерентності та передбачуваної моделі сейсмічного запису запропоновано новий метод оцінки когерентності. Метод забезпечує більшу чутливість когерентності у присутності залишкових часових зсувів після врахування локального нахилу у вікні аналізу. Він ґрунтується на більш реалістичній моделі сейсмічного запису, яка допускає довільні варіації амплітуди сигналу, дисперсії завади та залишкових часових зсувів. Новій метод апробовано на теоретичних та реальних даних.In the paper after analyzing the relation of coherence to the supposed mathematical model of seismic data, a new method is presented. It makes coherence more sensitive to the presence of residual time delay fluctuations of the signal after removal of its average local dip in the analysis window. The method is based on a more realistic data model that permits arbitrary trace-to-trace variations in signal amplitude, signal time delay and noise variance. The novel method is tested and compared with conventional approaches on synthetic and field data sets

    On QCD analysis of stucture function F2γF_2^{\gamma} in alternative approach

    Full text link
    The alternative approach to QCD analysis of the photon structure function F2γF_2^{\gamma} is presented. It differs from the conventional one by the presence of the terms which in conventional approach appear in higher orders. We show that this difference concerns also the photonic parton distribution functions. In the alternative approach, the complete LO analysis of F2γF_2^{\gamma} can be performed as all required quantities are known. At the NLO, however, one of the coefficient function is so far not available and thus only the photonic parton distribution function can be computed and compared to those of standard approach. We discuss the numerical difference of these approaches at the LO and the NLO approximation and show that in case of F2γF_2^{\gamma} this difference is non-negligible and may play an important role in the analysis on photon data of the future experiments.Comment: 25 page

    A New 5 Flavour NLO Analysis and Parametrizations of Parton Distributions of the Real Photon

    Full text link
    New, radiatively generated, NLO quark (u,d,s,c,b) and gluon densities in a real, unpolarized photon are presented. We perform three global fits, based on the NLO DGLAP evolution equations for Q^2>1 GeV^2, to all the available structure function F_2^gamma(x,Q^2) data. As in our previous LO analysis we utilize two theoretical approaches. Two models, denoted as FFNS_{CJK}1 & 2 NLO, adopt the so-called Fixed Flavour-Number Scheme for calculation of the heavy-quark contributions to F_2^gamma(x,Q^2), the CJK NLO model applies the ACOT(chi) scheme. We examine the results of our fits by a comparison with the LEP data for the Q^2 dependence of the F_2^gamma, averaged over various x-regions, and the F_2,c^gamma. Grid parametrizations of the parton densities for all fits are provided.Comment: 49 pages, 27 postscript figures; FORTRAN programs available at http://www.fuw.edu.pl/~pjank/param.htm

    Uncertainties of the CJK 5 Flavour LO Parton Distributions in the Real Photon

    Full text link
    Radiatively generated, LO quark (u,d,s,c,b) and gluon densities in the real, unpolarized photon, calculated in the CJK model being an improved realization of the CJKL approach, have been recently presented. The results were obtained through a global fit to the experimental F2^gamma data. In this paper we present, obtained for the very first time in the photon case, an estimate of the uncertainties of the CJK parton distributions due to the experimental errors. The analysis is based on the Hessian method which was recently applied in the proton parton structure analysis. Sets of test parametrizations are given for the CJK model. They allow for calculation of its best fit parton distributions along with F2^gamma and for computation of uncertainties of any physical value depending on the real photon parton densities. We test the applicability of the approach by comparing uncertainties of example cross-sections calculated in the Hessian and Lagrange methods. Moreover, we present a detailed analysis of the chi^2 of the CJK fit and its relation to the data. We show that large chi^2/DOF of the fit is due to only a few of the experimental measurements. By excluding them chi^2/DOF approx 1 can be obtained.Comment: 28 pages, 8 eps figures, 2 Latex figures; FORTRAN programs available at http://www.fuw.edu.pl/~pjank/param.html; table 10, figure 10 and section 6 correcte

    On Tamm's problem in the Vavilov-Cherenkov radiation theory

    Get PDF
    We analyse the well-known Tamm problem treating the charge motion on a finite space interval with the velocity exceeding light velocity in medium. By comparing Tamm's formulae with the exact ones we prove that former do not properly describe Cherenkov radiation terms. We also investigate Tamm's formula cos(theta)=1/(beta n) defining the position of maximum of the field strengths Fourier components for the infinite uniform motion of a charge. Numerical analysis of the Fourier components of field strengths shows that they have a pronounced maximum at cos(theta)=1/(beta n) only for the charge motion on the infinitely small interval. As the latter grows, many maxima appear. For the charge motion on an infinite interval there is infinite number of maxima of the same amplitude. The quantum analysis of Tamm's formula leads to the same results.Comment: 28 pages, 8 figures, to be published in J.Phys.D:Appl.Phy

    Hypernuclei as chiral solitons

    Full text link
    The identification of flavored multiskyrmions with the ground states of known hypernuclei is successful for several of them, e.g. for isodoublet H(Lambda) - He(Lambda), A=4, isoscalars He(Lambda) (A=5) and Li(Lambda) (A=7). In other cases agreement is not so good, but the behaviour of the binding energy with increasing baryon number is in qualitative agreement with data. Charmed or beauty hypernuclei within this approach are predicted to be bound stronger than strange hypernuclei. This conclusion is stable against variation of poorly known heavy flavor decay constants.Comment: 9 pages, 1 Fig. Presented at the International Workshops on Nuclear and Particle Physics at 50-Gev PS, NP01 (KEK, Japan, December 2001) and NP02 (Kyoto, Japan, September 2002). Some additions and corrections of numerical results are mad

    The influence of climatic factors on the course of pregnancy in women of the far north

    Get PDF
    The article describes the influence of climatic and geographic conditions on the course of pregnancy in women of the Tazovsky district in the far North (Yamalo-Nenets). After analyzing the course of pregnancy on individual cards found that the course of pregnancy has a significant effect on the change in photoperiodicity. In the years of high solar activity, the frequency of complications increases in indigenous and alien residents. In this regard, it is necessary to carry out preventive measures to identify and eliminate complications during pregnancy in all residents of the NorthВ статье рассмотрено влияние климато-географических условий на течение беременности у жительниц Тазовского района Крайнего Севера (ЯНАО). Проанализировав течение беременности по индивидуальным картам установлено, что на течение беременности существенное влияние оказывает изменение фотопериодичности. В годы высокой солнечной активности частота осложнений возрастает у коренных и пришлых жительниц. В связи с этим необходимо проведение профилактических мероприятий по выявлению и устранению осложнений на течение беременности у всех жительниц Север

    The influence of climatic factors on the course of pregnancy in women of the far north

    Get PDF
    The article describes the influence of climatic and geographic conditions on the course of pregnancy in women of the Tazovsky district in the far North (Yamalo-Nenets). After analyzing the course of pregnancy on individual cards found that the course of pregnancy has a significant effect on the change in photoperiodicity. In the years of high solar activity, the frequency of complications increases in indigenous and alien residents. In this regard, it is necessary to carry out preventive measures to identify and eliminate complications during pregnancy in all residents of the NorthВ статье рассмотрено влияние климато-географических условий на течение беременности у жительниц Тазовского района Крайнего Севера (ЯНАО). Проанализировав течение беременности по индивидуальным картам установлено, что на течение беременности существенное влияние оказывает изменение фотопериодичности. В годы высокой солнечной активности частота осложнений возрастает у коренных и пришлых жительниц. В связи с этим необходимо проведение профилактических мероприятий по выявлению и устранению осложнений на течение беременности у всех жительниц Север

    Study of Leading Hadrons in Gluon and Quark Fragmentation

    Get PDF
    The study of quark jets in e+e- reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However, our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo Simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (<~ 2 GeV/c^2) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.Comment: 19 pages, 6 figures, Accepted by Phys. Lett.
    corecore