97 research outputs found
An analysis of a minimal vectorlike extension of the Standard Model
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
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
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
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() hyperfine excitation spectra due to optical pumping in the weak excitation limit
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 and 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
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
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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