Motivation to football students of higher educational institutions

The aim of this work is to define factors contributing to increased motivation to playing football in the system of sports and recreational activities. Football is regarded as a kind of recreational activity. It is established that for most students, classes recreational games are a means of promoting health, well-being, improve the bodyЦелью работы является определение факторов, способствующих повышению мотивации к занятиям футболом в системе физкультурно-оздоровительных занятий. Рассматривается футбол как вид рекреационной деятельности. Установлено, что для большинства студентов занятия рекреационными играми являются средством укрепления здоровья, хорошего самочувствия, улучшения телосложени

Dynamics of Primordial Hydrogen Recombination with Allowance for a Recoil for Scattering in the Ly-alpha Line

It is shown that taking into account a recoil for radiation scattering in the Ly-alpha line can lead to a noticable acceleration of primordial hydrogen recombination. Thus for LambdaCDM model a decrease of ionization degree exceeds 1% for redshifts z in a range 800 - 1050 achieving approximately 1.3% at z=900. Corresponding corrections to the cosmic microwave background power spectra can achieve 1.1% for TT spectra and 1.7% for EE ones. Radiative transfer in these calculations was treated in a quasistationary approximation. Numerical solutions are also obtained in diffusion approximation for a nonstationary problem of Ly-alpha line radiative transfer under partial frequency redistribution with a recoil. An evolution of a local line profile is traced to as well as an evolution of a relative number of uncompensated transitions from 2p state down to 1s one. It is shown that taking into account nonstationarity of Ly-alpha line radiative transfer can lead to an additional acceleration of primordial hydrogen recombination.Comment: 9 pages, 5 figures; accepted for publication in Astronomy Letter

The basic methodology of physical therapy for diseases of the respiratory system

The article discusses the methods of exercise therapy for diseases of the respiratory system, types of exercises, indications for their use and the processes that occurВ статье рассматриваются методики ЛФК при заболевании дыхательной системы, виды упражнений, показания к их применению и процессы, которые при этом происходя

Elastic Spin Relaxation Processes in Semiconductor Quantum Dots

Electron spin decoherence caused by elastic spin-phonon processes is investigated comprehensively in a zero-dimensional environment. Specifically, a theoretical treatment is developed for the processes associated with the fluctuations in the phonon potential as well as in the electron procession frequency through the spin-orbit and hyperfine interactions in the semiconductor quantum dots. The analysis identifies the conditions (magnetic field, temperature, etc.) in which the elastic spin-phonon processes can dominate over the inelastic counterparts with the electron spin-flip transitions. Particularly, the calculation results illustrate the potential significance of an elastic decoherence mechanism originating from the intervalley transitions in semiconductor quantum dots with multiple equivalent energy minima (e.g., the X valleys in SiGe). The role of lattice anharmonicity and phonon decay in spin relaxation is also examined along with that of the local effective field fluctuations caused by the stochastic electronic transitions between the orbital states. Numerical estimations are provided for typical GaAs and Si-based quantum dots.Comment: 57 pages, 14 figure

Abrupt changes in atmospheric methane at the MIS 5b–5a transition

New ice core analyses show that the prominent rise in atmospheric methane concentration at Dansgaard-Oeschger event 21 was interrupted by a century-long 20% decline, which was previously unrecognized. The reversal was found in a new ∼100-year resolution study of methane in the GISP2 ice core, encompassing the beginning of D-O event 21, which also corresponds to the transition from MIS 5b to 5a. Although a corresponding reversal (within age uncertainty) is observed in climate proxies measured in GISP2 ice, including δ¹⁸O[subscript ice], electrical conductivity, light scattering, and several ions, this feature has not been discussed previously. Abrupt changes in methane are paralleled by changes in δ¹⁵N of trapped air, a quantity that reflects local temperature change at Greenland summit. The reversal described here supports the hypothesis that climate can be unstable during major transitions, as was previously described for the last deglaciation.This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gl

ENVIRONMENTALLY FRIENDLY METHOD OF GASEOUS FUEL COMBUSTION WITH THE USE OF QUASI-OPTICAL MICROWAVE

Subject of Research.The paper deals with the problem of developing low emission combustors operating on natural gas or LPG, to reduce emissions of nitrogen oxides NOx. The possibility of burning very lean fuel mixtures is studied. To initiate the ignition and combustion stabilization the discharge generated by the quasi-optical microwave is used. Main Results. Initiating ignition by streamer microwave discharge increases the rate of combustion and combustion efficiency about four times as compared with the conventional spark ignition. Streamer discharge ignition by very lean fuel-air mixture is demonstrated with the factor of oxiding agent excess greater than the limit of explosive range under normal conditions. According to indirect indicators, ignition by microwave discharge created by quasi-optical radiation is of non-thermal nature. Microwave discharge excites oxygen atoms, and intense ultra-violet radiation is generated as a result that causes formation of cold nonequilibrium plasma with avalanche growth of free electrons. Streamer discharge propagates at a speed of 5 km /s, so the initiation of the ignition occurs immediately throughout. The temperature of the fuel mixture at the point of ignition initiation does not exceed 400 К.There is no area with a temperature sufficient to initiate thermal Zeldovich mechanism of emission of nitrogen oxides. Combustion rate is high. As a result the Fenimore mechanism of "fast nitrogen oxides" has no chance to be progressing, and NOx emissions in appreciable quantities are excluded. Energy costs are comparable with spark ignition.Practical Relevance. The studied technology is designed for low emission internal combustion engines, power gas turbines, gas compressor units, fueled by natural gas

Atmospheric Gravity Perturbations Measured by Ground-Based Interferometer with Suspended Mirrors

A possibility of geophysical measurements using the large scale laser interferometrical gravitational wave antenna is discussed. An interferometer with suspended mirrors can be used as a gradiometer measuring variations of an angle between gravity force vectors acting on the spatially separated suspensions. We analyze restrictions imposed by the atmospheric noises on feasibility of such measurements. Two models of the atmosphere are invoked: a quiet atmosphere with a hydrostatic coupling of pressure and density and a dynamic model of moving region of the density anomaly (cyclone). Both models lead to similar conclusions up to numerical factors. Besides the hydrostatic approximation, we use a model of turbulent atmosphere with the pressure fluctuation spectrum f^{-7/3} to explore the Newtonian noise in a higher frequency domain (up to 10 Hz) predicting the gravitational noise background for modern gravitational wave detectors. Our estimates show that this could pose a serious problem for realization of such projects. Finally, angular fluctuations of spatially separated pendula are investigated via computer simulation for some realistic atmospheric data giving the level estimate 10^{-11} rad/sqrt(Hz) at frequency 10^{-4} Hz. This looks promising for the possibility of the measurement of weak gravity effects such as Earth inner core oscillations.Comment: 13 pages, 4 pigures, LaTeX. To be published in Classical and Quantum Gravit

Relative timing and variability of atmospheric methane and GISP2 oxygen isotopes between 68 and 86 ka

The global biogeochemical cycle of methane has received wide attention because of methane's role as a greenhouse gas. Measurements of methane in air trapped in Greenland ice cores provide a high-resolution record of methane levels in the atmosphere over the past ~100 ka, providing clues about what controls the methane cycle on geologic timescales. Remarkable similarity between local temperature recorded in Greenland ice cores and changes in global methane concentrations has been noted in previous studies, with the inference that the local temperature variations have global significance, but the resolution of sampling and measurement precision limited fine-scale comparison of these variables. In this work a higher-precision (~2 ppb) methane data set was obtained from the Greenland Ice Sheet Project 2 (GISP2) ice core for the time interval between 86 and 68 ka, encompassing three large abrupt warming events early in the last glacial period: Dansgaard-Oeschger (D-O) events 19, 20, and 21. The new data set consists of duplicate measurements at 158 depths, with average time resolution of 120 years. Such detailed measurements over D-O 21, the longest in Greenland records, have not yet been reported for other ice cores. The new data set documents short-term variability (~20 ppb typical amplitude), which is remarkably persistent, and in many cases similar features are observed in the most detailed published δ¹⁸O[subscript ice] record. High-precision GISP2 δ¹⁵N data show that changes in Greenland temperature are synchronous with the methane variations at the onset of D-O events 19, 20, and 21, supporting previous results from the Greenland Ice Core Project ice core for D-O 19 and 20. Cross-spectral analysis quantifies the extremely close similarity between the new methane record and the δ¹⁸O[subscript ice] record. Because methane sources are widely distributed over the globe, this work further validates δ¹⁸O[subscript ice] at Greenland summit as a geographically broad climate indicator on millennial to multicentennial timescales.Keywords: methane, Dansgaard-Oeschger events, ice core