237 research outputs found

    QED radiative corrections to impact factors

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    We consider the radiative corrections to the impact factors of electron and photon. According to a generalized eikonal representation the e\bar e scattering amplitude at high energies and fixed momentum transfers is proportional to the electron form factor. But we show that this representation is violated due to the presence of non-planar diagrams. One loop correction to the photon impact factor for small virtualities of the exchanged photon is obtained using the known results for the cross section of the e\bar e production at photon-nuclei interactions.Comment: 8 pp, plain LaTe

    Modern theoretical, methodological approaches to health formation among students in the pedagogical process

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    Student’s health problems have been identified in the 21st century. These burning problems need integrated solution. The system of education is also responsible for the current situation. Professional activity of the pedagogical community in healthsaving should be aimed at formation of healthy lifestyle values both in and out of classroomПроблемы здоровья школьника, выявленные в 21 веке и ставшие очень острыми, нужно решать комплексно. Свою долю ответственности за сложившуюся ситуацию несет и система образования. Профессиональная деятельность педагогического сообщества по здоровьесбережению должна вестись не только на учебных занятиях, но и во внеурочное время и быть направленной на формирование ценности здорового образа жизн

    Hemodynamics monitoring in sport: Using hemodynamic monitor for sport training planning

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    The study stresses the meaning of the physiological measures that are obtained with the functional diagnostics devices and how these values can be used in coaching sportsmen. Methods: Hemodynamic monitor was used for monitoring hemodynamics and heart function of athletes (n=305) with different fitness levels. Active orthoclinostatic tests and antiorthostatic tests with passive body position changing were carried out with hemodynamics measurements recorded. Results: The most informative indicators and indices of heart function for high performance sport and their values at rest were detected. Along with common hemodynamics indicators (HR, SV, CO, EDV, blood pressure, etc.) the possibility of using correlation rhythmogram in coaching was studied. The correlation rhythmogram "cloud" dependence on athletes' fitness level was revealed in transient during active orthoclinostatic test

    Biocompatibility of Bare Nanoparticles Based on Silicon and Gold for Nervous Cells

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    This work aimed to investigate the biocompatibility of bare (ligand-free) lasersynthesized nanoparticles (NPs) based on silicon (Si) and gold (Au) with primary hippocampal cultures. 1%, 5% and 7% of culture medium were replaced by 0.1 mg/mL NP solution on day 14 of culture development in vitro. Our studies revealed that the NPs caused a dose-dependent cytotoxic effect, which was manifested by an increase the number of dead cells and a decrease of the spontaneous functional calcium activity of neural networks. Au NPs revealed less pronounced cytotoxic effect than Si ones and it can be explained by larger size and better solubility of Si NPs. Keywords: bare nanoparticles, primary hippocampal cultures, neurotoxicit

    Современные методы расчета тормозного излучения в процессах взаимодействия элементарных частиц

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    . The problem of real bremsstrahlung calculation is considered using the modern methods of regularization of divergencies. In particular, we calculate soft photon bremsstrahlung in the most general form using the method of dimensional regularization of infrared divergences. The general calculation algorithm of hard photon bremsstrahlung is described. It is shown that the contribution of hard bremsstrahlung can be separated into the finite and divergent parts. The divergent part can be factorized with the contribution of the initial process in the Born approximation. It is shown that a good choice of kinematic variables makes an analytic covariant calculation of the divergent part of the hard bremsstrahlung possible. In a particular case, an algorithm for determining the kinematic constraints on the invariants is described. A numerical analysis of the radiative corrections for gauge bosons production processes in the case of electron-photon collisions is performed. It is discovered that the contribution of the finite part of bremsstrahlung at high collision energies reaches 20 per cent and must be taken into account in calculations of radiative corrections. The results obtained can be used in various calculations, including covariant ones, performed in the context of confirmation of the Standard Model theoretical predictions or searching for manifestations of alternative gauge models.Рассмотрена проблема расчета вклада тормозного излучения с использованием современных методов регуляризации расходимостей. В частности, проведен расчет мягкофотонного излучения в наиболее общем виде с использованием метода размерной регуляризации инфракрасных расходимостей. Описан общий алгоритм расчета жесткого тормозного излучения. Показано, что можно разделить вклад жесткого тормозного излучения на конечную и расходящуюся части. Расходящаяся часть может быть факторизована с вкладом исходного процесса в борновском приближении. Показано, что при удачном выборе кинематических переменных возможен аналитический ковариантный расчет расходящейся части жесткого тормозного излучения. В частном случае приведен алгоритм определения кинематических ограничений на используемые инварианты. Проведен численный анализ вклада радиационных поправок для процессов рождения калибровочных бозонов в случае электрон-фотонных столкновений. Обнаружено, что вклад конечной части излучения тормозных фотонов при высоких энергиях столкновений достигает 20 % и обязательно должен учитываться в расчетах радиационных поправок. Полученные результаты можно применять в различного рода расчетах, в том числе и в ковариантном виде, производимых в контексте подтверждения теоретических предсказаний Стандартной модели или поиска проявлений альтернативных калибровочных моделей

    Combined use of pulse therapy and molecular hydrogen in rats with experimental rheumatoid arthritis: Clinical and histological evaluation of therapeutic effectiveness

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    The search for new therapeutic options for rheumatoid arthritis is expanded due to major antioxidant substances that can reduce duration of treatment, while ensuring positive dynamics of the course of the diseas

    Some Peculiarities in the Dose Dependence of Separate and Combined In Vitro Cardiotoxicity Effects Induced by CdS and PbS Nanoparticles With Special Attention to Hormesis Manifestations

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    Spherical nanoparticles (NPs) of cadmium and lead sulfides (diameter 37 ± 5 and 24 ± 4 nm, respectively) have been found to be cytotoxic for HL-1 cardiomyocytes as evidenced by decrease in adenosine triphosphate–dependent luminescence. Cadmium sulfide (CdS)-NPs were discovered to produce a much greater cytotoxic impact than lead sulphide (PbS)-NP. Given the same dose range, CdS-NP reduced the number of calcium spikes. A similar effect was observed for small doses of PbS-NP. In addition to cell hypertrophy under the impact of certain doses of CdS-NP and PbS-NP, doses causing cardiomyocyte size reduction were identified. For these 3 outcomes, we obtained both monotonic “dose–response” functions (well approximated by the hyperbolic function) and different variants of non-monotonic ones for which we found adequate mathematical expressions by modifying certain models of hormesis available in the literature. Data analysis using a response surface linear model with a cross-term provided new support to the previously established postulate that a diversity of types of joint action characteristic of one and the same pair of damaging agents is one of the important assertions of the general theory of combined toxicity. © The Author(s) 2020
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