97 research outputs found

    An analysis of a minimal vectorlike extension of the Standard Model

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    We analyze an extension of the Standard Model with an additional SU(2) hypercolor gauge group keeping the Higgs boson as a fundamental field. Vectorlike interactions of new hyperquarks with the intermediate vector bosons are explicitly constructed. We also consider pseudo-Nambu--Goldstone bosons caused by the symmetry breaking SU(4)-> Sp(4). A specific global symmetry of the model with zero hypercharge of the hyperquark doublets ensures the stability of a neutral pseudoscalar field. Some possible manifestations of the lightest states at colliders are also examined.Comment: 16 pages, 1 table, v.2: minor modification, reference is added, formula (62) is correcte

    Ionization of Sodium and Rubidium nS, nP and nD Rydberg atoms by blackbody radiation

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    Results of theoretical calculations of ionization rates of Rb and Na Rydberg atoms by blackbody radiation (BBR) are presented. Calculations have been performed for nS, nP and nD states of Na and Rb, which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at three ambient temperatures of 77, 300 and 600 K. A peculiarity of our calculations is that we take into account the contributions of BBR-induced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect both the magnitude of measured ionization rates and shapes of their dependencies on n. The calculated ionization rates are compared with the results of our earlier measurements of BBR-induced ionization rates of Na nS and nD Rydberg states with n=8-20 at 300 K. A good agreement for all states except nS with n>15 is observed. We also present the useful analytical formulae for quick estimation of BBR ionization rates of Rydberg atoms.Comment: 14 pages, 6 figures, 6 tables in Appendi

    Application of isokinetic extremity system in sport medicine and rehab practice

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    The literature review discusses current trends in the isokinetic machines (IM) use for both training and diagnostic purposes. The review dwells upon a wide range of IM applications, testing and training results, and demonstrates the applied nature of the IM use. The review addresses the issues IM use in professional sports. We come to the conclusion about a wide range of IM applications in both research and clinical practice. Despite IM disadvantages (high cost, necessity of special staff training, test results variability depending on an IM model), IM is a powerful tool in a health care professional’s arsenal which provides a qualitative improvement of clinical practice

    The assessment of the structure of anti-doping rules violation and the evaluation of anti-doping measures efficiency in Russian athletics during 2000–2020

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    The assessment of the structure and trends of doping perpetrations among athletes with a proven high prevalence of doping use might be of great practical interest. Non-compliance with the zero-tolerance policy towards anti-doping rules violators among sports communities with a high prevalence of doping offenses is the main cause of the ineffective fight against doping.Objective: to analyze the structure of anti-doping rule violations and evaluate the effectiveness of measures to counter the spread of doping in Russian athletics in 2000–2020.Materials and methods: to form an objective picture, a database was collected on all anti-doping rule violators in Russian athletics from 2000 to June 01, 2020 from open sources. Retrospective analysis of the protocols of all official competitions held in Russia since 2000 and included in the RUSAF Unified Schedule was performed.Results: 381 cases of anti-doping rule violation committed during 2000–2020 period by 355 athletes were registered. 25 athletes committed 2 doping offenses and 1 athlete 3 ones. Women perpetrated more offenses than men.Conclusions: our study objectified the doping issue in Russian athletics and evaluated the effectiveness of anti-doping measures. The study indicates the need to stop ignoring zero-tolerance policy principles towards doping offenders among the athletic community and creates an incentive to develop functional mechanisms to combat doping

    Broadening and intensity redistribution in the Na(3p3p) hyperfine excitation spectra due to optical pumping in the weak excitation limit

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    Detailed analysis of spectral line broadening and variations in relative intensities of hyperfine spectral components due to optical pumping is presented. Hyperfine levels of sodium 3p1/23p_{1/2} and 3p3/23p_{3/2} levels are selectively excited in a supersonic beam at various laser intensities under the conditions when optical pumping time is shorter than transit time of atoms through the laser beam. The excitation spectra exhibit significant line broadening at laser intensities well below the saturation intensity, and redistribution of intensities of hyperfine spectral components is observed, which in some cases is contradicting with intuitive expectations. Theoretical analysis of the dynamics of optical pumping shows that spectral line broadening depends sensitively on branching coefficient of the laser-driven transition. Analytical expressions for branching ratio dependent critical Rabi frequency and critical laser intensity are derived, which give the threshold for onset of noticeable line broadening by optical pumping. Transitions with larger and smaller branching coefficients are relatively less affected. The theoretical excitation spectra were calculated numerically by solving density matrix equations of motion using the split propagation technique, and they well reproduce the observed effects of line broadening and peak intensity variations. The calculations also show that presence of dark (i.e., not laser- coupled) Zeeeman sublevels in the lower state results in effective branching coefficients which vary with laser intensity and differ from those implied by the sum rules, and this can lead to peculiar changes in peak ratios of hyperfine components of the spectra.Comment: 12 pages, 10 figure

    Исследование полисиалированного генно-инженерного инсулина человека

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    The method of structure determination of the recombinant glycosylated peptides and proteins has been elaborated by the example of the gene-spliced human insulin.На примере полисиалированного генно-инженерного инсулина человека разработан способ определения структуры гликозилированных рекомбинантных пептидов и белков, имеющих применение в медицине

    Хроматографический и масс-спектрометрический анализ гликозилированного генно-инженерного инсулина человека

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    The recombinant modified peptides and proteins method of structure and properties determination has been considered by the example of the glycosylated gene-spliced human insulin with disaccharide.Рассматривается способ определения структуры и свойств модифицированных рекомбинанатных пептидов и белков, на примере конъюгата генно-инженерного инсулина человека (ГИИЧ) с дисахаридом. Предлагается проводить ферментативный гидролиз, разделение гидролизатов методом обращенно-фазовой ВЭЖХ и последующий их анализ ESI-масс-спектрометрией. Место связывания инсулина с дисахаридом определяли по различию хроматографического поведения фрагментов, образующихся при гидролизе дисахаридил-инсулина и немодифицированного ГИИЧ
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