Collective and fractal properties of pion jets in the four-velocity space at intermediate energies

Experimental results are presented for study of collective and fractal properties of soft pion jets in the space of relative four-dimensional velocities. Significant decreasing is obtained for mean square of second particle distances from jet axis for pion-proton interactions at initial energies $\sim 3$ GeV in comparison with hadron-nuclear collisions at close energies. The decreasing results in power dependence of distance variable on collision energy for range $\sim 2 - 4$ GeV. The observation allows us to estimate the low boundary of manifestation of color degree of freedom in pion jet production. Cluster dimension values were deduced for pion jets in various reactions. Fractional values of this dimension indicate on the manifestation of fractal-like properties by pion jets. Changing of mean kinetic energy of jet particles and fractal dimension with initial energy increasing is consistent with suggestion for presence of color degrees of freedom in pion jet production at intermediate energies.Comment: The conference "Physics of fundamental interactions". ITEP, Moscow, Russia. November 23 - 27, 200

Magnon Bose condensation in symmetry breaking magnetic field

Magnon Bose condensation (BC)in the symmetry breaking magnetic field is a result of unusual form of the Zeeman energy, which has terms linear in the spin-wave operators and terms mixing excitations differ in the Wave-vector of the magnetic structure. The following examples are considered: simple easy-plane tetragonal antiferromagnets (AF), frustrated AF family$R_2Cu O_4$ where $R=Pr,Nd$ etc. and cubic magnets with the Dzyaloshinskii-Moriya interaction ($Mn Si$ etc.). In all cases the BC becomes important when the magnetic field becomes comparable with the spin-wave gap. The theory is illustrated by existing experimental results.Comment: Submitted to J. of Phys. Condens. Matter (Proceedings of International Conference "Highly Frustrated Magnets", Osaka (Japan), August 2006). 8 pages, 5 figure

Rare processes and coherent phenomena in crystals

We study coherent enhancement of Coulomb excitation of high energy particles in crystals. We develop multiple scattering theory description of coherent excitation which consistently incorporates both the specific resonant properties of particle-crystal interactions and the final/initial state interaction effects typical of the diffractive scattering. Possible applications to observation of induced radiative neutrino transitions are discussed.Comment: 8 pages, LaTe

Стабилизирующее управление неустойчивой системой с гироскопическими структурами на базе нечеткой логики

Робота присвячена дослідженню системи керування двоколісним транспортним засобом на основі нечіткої логіки. Метод управління реалізовано для системи стабілізації та динамічної рівноваги на прикладі гіроскопічного монорейкового вагона. Розроблено імітаційну модель об’єкту керування у середовищі LabVIEW, що дозволило проводити дослідження в режимі on-line, змінювати параметри моделі та характеристики керування в процесі виконання експерименту. Досліджено вплив зміни параметрів системи та потужності виконуючого пристрою на процес відновлення рівноваги. Проведено порівняння динамічних характеристик транспортного засобу на основі нечіткого керування та традиційного. Показано, що введення блока нечіткої логіки в систему керування в значній мірі зменшило час перехідного процесу та спожиту енергію.The method of synthesis management system implemented for dynamic and balance stabilization the example of gyroscopic monorail car. A simulation model among LabView, which allow to conduct research in a mode on-line, modify model parameters and characteristics of the control system. Researched parameters fluctuations when changing the angular momentum, mass and power load sensor point. Researched the parameters fluctuations when changing the angular momentum, mass and power load sensor point. Lead a comparison of the characteristics vehicle vibrations and traditional fuzzy control with the help of feedback. It is shown that the introduction of block of fuzzy logic in control greatly reduce the transition process and the consume energy.Рассмотрена возможность применения метода управления на основе нечеткой логики для создания устойчивой системы двухколесного транспортного средства. Метод синтеза управления реализован для системы стабилизации и динамического равновесия на примере гироскопического монорельсового вагона. Разработана имитационная модель в среде Labview, что позволило проводить исследование в режиме on-line, изменять параметры модели и характеристики системы управления. Исследовано поведение системы при изменении ее параметров и мощности исполнительного устройства. Проведено сравнение динамических характеристик транспортного средства на основе традиционного и нечеткого управлений. Показано, что введение блока нечеткой логики в систему управления в значительной мере уменьшает время переходного процесса и потребляемую энергию

Frequency and structure of endocrine diseases in young elite athletes

There is no data on the prevalence of endocrine disorders in young elite athletes in Russia.Objective: to assess the prevalence of endocrine pathologies and their structure in children and adolescents involved in elite sport.Materials and methods: the study included data from outpatient records of members of national sports teams, who underwent special medical examination. The data of a random sample of 1081 outpatient cards of young athletes, for 26 sports, were analyzed.Results: we found a high prevalence of endocrine pathology (18.6 %) in children and adolescents involved in high-performance sports. Thyroid diseases are most the most frequent in young athletes (in 57.3 % of cases). On second place is obesity (12.3 %). The frequency of weight deficiency and short stature is 8.4 % each. Autoimmune thyroiditis occupies a leading place in the structure of thyroid pathology in young elite athletes. Subclinical hypothyroidism takes the second place, and nodular goiter — the third place.Conclusion: young elite athletes are characterized by a high frequency of endocrine pathology, the leading place in which is occupied by thyroid diseases. It is necessary to further studies aimed at assessing the mechanisms of hormonal adaptation in elite young athletes to assess their impact on the development of the child and the correct interpretation of the hormonal profile obtained during a special medical examination

Effect of testosterone in young ice-hockey players on hematological, biochemical parameters and the level of physical performance

Ice-hockey combines intense physical activity at high speed with elements of power struggle. Testosterone is the main anabolic hormone, an increase in which during adolescence is associated with faster growth, increased muscle mass, physical strength, and increased overall and aerobic performance. Thus, it is interesting to study the effect of different testosterone levels on metabolic parameters and physical performance of young ice-hockey players.Objective: to compare hematological and biochemical parameters, as well as exercise performance in young ice-hockey players, depending on the testosterone level.Materials and methods: the study included 100 young ice-hockey players aged 15–17 years (average age 15.3 ± 1.1 years). The study group included 25 young ice-hockey players with an increased level of total blood testosterone (> 27.5 nmol/l). The control group included 75 young athletes with normal testosterone levels. All athletes included in the study underwent the PWC 170 test to assess physical performance. Assessment of hematological parameters included hemoglobin (HGB), hematocrit, red blood cell, mean corpuscular volume (MCV), mean concentration hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). β-crosslaps, myoglobin and creatine phosphokinase (CPK) activity were measured to assess the functional state of muscle and bone tissue.Results: A comparative assessment of the CBC in young ice-hockey players did not reveal significant differences depending on the level of serum testosterone level. Tolerance to physical activity in the study groups also did not differ. Young ice-hockey players with increased testosterone levels showed lower β-crosslaps values compared to the control group. The values of other biomarkers of the functional activity of muscle tissue did not depend on the level of testosterone levels.Conclusion: Increased serum testosterone level in the range from 27.5 to 40 nmol/l, detected in young ice-hockey players aged 15–17 years, is not associated with a change in hematological and biochemical parameters. High total testosterone levels do not improve physical performance. It is necessary to continue studies to assess the dynamics of the serum testosterone in young ice-hockey players to clarify the long-term effects of androgens on the metabolic and functional indicators of young athletes. Increasing serum testosterone levels in athletes is subject to wide discussion in the community of sports physicians and endocrinologists

Elastic scattering of hadrons

Colliding high energy hadrons either produce new particles or scatter elastically with their quantum numbers conserved and no other particles produced. We consider the latter case here. Although inelastic processes dominate at high energies, elastic scattering contributes considerably (18-25%) to the total cross section. Its share first decreases and then increases at higher energies. Small-angle scattering prevails at all energies. Some characteristic features are seen that provide informationon the geometrical structure of the colliding particles and the relevant dynamical mechanisms. The steep Gaussian peak at small angles is followed by the exponential (Orear) regime with some shoulders and dips, and then by a power-law drop. Results from various theoretical approaches are compared with experimental data. Phenomenological models claiming to describe this process are reviewed. The unitarity condition predicts an exponential fall for the differential cross section with an additional substructure to occur exactly between the low momentum transfer diffraction cone and a power-law, hard parton scattering regime under high momentum transfer. Data on the interference of the Coulomb and nuclear parts of amplitudes at extremely small angles provide the value of the real part of the forward scattering nuclear amplitude. The real part of the elastic scattering amplitude and the contribution of inelastic processes to the imaginary part of this amplitude (the so-called overlap function) at nonforward transferred momenta are also discussed. Problems related to the scaling behavior of the differential cross section are considered. The power-law regime at highest momentum transfer is briefly described.Comment: 72 pages, 11 Figures; modified Physics-Uspekhi 56 (2013)