GRAVITY’S ROLE IN ACCELERATED RUNNING - A COMPARISON OF AN EXPERIENCED POSE® AND HEEL-TOE RUNNER

The purpose of this study was to determine gravity’s role in accelerated running using an experienced male Pose® and heel-toe runner as a comparison. A two-step accelerated run found that maximum horizontal acceleration of the centre of mass (COM) occurred before maximum horizontal ground reaction force (GRF). Maximum horizontal and angular acceleration of the arms and trunk occurred at or before maximum horizontal acceleration of the COM. At maximum horizontal GRF both participants’ stance feet were vertically accelerated. It is suggested that acceleration of the COM occurs via a gravitational torque with GRF being the consequence of, not the cause of these movements. Therefore, practitioners might find this novel perspective helpful when applied to accelerated running

Time-dependent angularly averaged inverse transport

This paper concerns the reconstruction of the absorption and scattering parameters in a time-dependent linear transport equation from knowledge of angularly averaged measurements performed at the boundary of a domain of interest. We show that the absorption coefficient and the spatial component of the scattering coefficient are uniquely determined by such measurements. We obtain stability results on the reconstruction of the absorption and scattering parameters with respect to the measured albedo operator. The stability results are obtained by a precise decomposition of the measurements into components with different singular behavior in the time domain

Exciton spin decay modified by strong electron-hole exchange interaction

We study exciton spin decay in the regime of strong electron-hole exchange interaction. In this regime the electron spin precession is restricted within a sector formed by the external magnetic field and the effective exchange fields triggered by random spin flips of the hole. Using Hanle effect measurements, we demonstrate that this mechanism dominates our experiments in CdTe/(Cd,Mg)Te quantum wells. The calculations provide a consistent description of the experimental results, which is supported by independent measurements of the parameters entering the model.Comment: 5 pages, 3 figure

A COMPARISON OF PEDALING MECHANICS IN EXPERIENCED POSE AND TRADITIONAL CYCLISTS

The purpose of this study was to describe the mechanical differences between two experienced male Pose cyclists and traditional cyclists. Pose cycling requires a specific set-up that attempts to place the centre of mass over the pedal to increase the non-muscular force/power component during the downstroke. Results revealed that for the Pose cyclists the centre of mass was closer to vertically above the pedal when in the horizontal forward position. Non-muscular contributions to pedal power tended to be greater in the Pose cyclists compared to the traditional cyclists. In addition, we found joint differences in the power contribution to pedal power in the traditional cyclists who relied more heavily on contributions from the muscles spanning the knee joint, whereas Pose cyclists had greater ankle and hip power contributions

Battle of Stalingrad in the diaries of junior lieutenant Rudnitsky

The authors of the article examine the events of the Battle of Stalingrad through the prism of the diary entries of Junior Lieutenant Z.S. Rudnitsky. The authors set themselves a number of tasks for revealing the topic: to show the role of air defense and its contribution to the victory at Stalingrad; evaluate the level of material and technical supply of the Red Army, evaluate the value of front-line diaries as a historical source. The relevance of this topic is explained by the need to understand the processes that resulted in the greatest military victory of World War II, as well as the increased interest in diaries as a historical source, which researchers attribute to the so-called soft communicative memory. The novelty of the study is the introduction into the scientific circulation of a previously unknown source the front-line diary of Z.S. Rudnitsky, which he led throughout the battle of Stalingrad. The value of the present source lies in the display of direct perception of the war through the eyes of a young nineteen-year-old lieutenant. Working with the materials of diary entries allowed to deepen our ideas about supplying and arming the defenders of Stalingrad, their moral condition, domestic problems. The study was carried out as part of the problem field of memory studies using retrospective, comparative historical, interdisciplinary methods. Based on an analysis of everyday life of the front lieutenant Rudnitsky, who fought on the Stalingrad front as part of the 303 artillery-anti-aircraft regiment, it was concluded that the daily military feat of the anti-aircraft gunners made it possible to block the sky over the city for German aviation, especially during the counteroffensive. The value of this feat becomes even more obvious against the background of an extremely difficult state and a lack of machinery, equipment, household inconveniences. It is concluded that it is necessary to introduce into the scientific circulation diaries that significantly expand the range of historical sources

Некоторые экологические особенности инкубации куриных яиц [Some ecological peculiarities of incubation of chicken eggs]

Нарушин В.Г.; Романов М.Н. Выводы: Параметры скорлупы куриных яиц являются достаточно информативными показателями при оценке их инкубационных свойств. Очевидно, в первую очередь это обусловлено физическими характеристиками естественной преграды на пути микроорганизмов, которой является скорлупа. Эффект тонкой скорлупы отрицательно влиял на результаты инкубации, так же, как и слишком большая поверхность скорлупы по отношению к величине яйца, что связано с относительно большим количеством пор. Предложенная методика, основанная на анализе расположения измеряемых параметров в исследуемой статистической выборке, позволяет оценить инкубационные свойства куриных яиц до закладки в инкубатор. Использование метода предынкубационного отбора яиц экономически целесообразно. В рамках проведенных исследований количество невыведенных яиц можно сократить почти вдвое при их своевременной оценке и выбраковке

Evolutionary relationships of Red Jungle Fowl and chicken breeds

Published results were reassessed and original data are provided regarding the origin and relatedness of four postulated chicken breed lineages, egg-type, game, meat-type and Bantam, to each other and to the basic ancestral species of jungle fowls, Gallus gallus. A system approach was employed concerning the planning of the experiments. One element of the system approach is the choice of the breeds to be compared with G. gallus. These breeds were supposed to represent major evolutionary branches of chickens. Four experiments on genetic relationships were conducted using different estimation criteria including morphological discrete characters, body measurements, biochemical markers, and the activity of serum esterase-1. The greatest similarity was found between G. gallus and the egg-type breeds of Mediterranean roots and/or true Bantams. This fact might testify that the indicated chicken groups occupied earlier stages in the evolution from the wild progenitor to the present biodiversity of chickens in the world

Singlet Ground State and Magnetization Plateaus in Ba3_3Mn2_2O8_8

Magnetic susceptibility and the magnetization process have been measured in \green polycrystal. In this compound, the magnetic manganese ion exists as Mn$^{5+}$ in a tetrahedral environment, and thus the magnetic interaction can be described by an S=1 Heisenberg model. The ground state was found to be a spin singlet with an excitation gap $\Delta/k_{\rm B}=11.2$ K. Magnetization plateaus were observed at zero and at half of the saturation magnetization. These results indicate that the present system can be represented by a coupled antiferromagnetic dimer model.Comment: 4 pages, 4 figures, jpsj styl

Phase-space structures in quantum-plasma wave turbulence

The quasilinear theory of the Wigner-Poisson system in one spatial dimension is examined. Conservation laws and properties of the stationary solutions are determined. Quantum effects are shown to manifest themselves in transient periodic oscillations of the averaged Wigner function in velocity space. The quantum quasilinear theory is checked against numerical simulations of the bump-on-tail and the two-stream instabilities. The predicted wavelength of the oscillations in velocity space agrees well with the numerical results