Shock waves in ultracold Fermi (Tonks) gases

It is shown that a broad density perturbation in a Fermi (Tonks) cloud takes a shock wave form in the course of time evolution. A very accurate analytical description of shock formation is provided. A simple experimental setup for the observation of shocks is discussed.Comment: approx. 4 pages&figures, minor corrections^2, to be published as a Letter in Journal of Physics

Bright solitons in Bose-Fermi mixtures

We consider the formation of bright solitons in a mixture of Bose and Fermi degenerate gases confined in a three-dimensional elongated harmonic trap. The Bose and Fermi atoms are assumed to effectively attract each other whereas bosonic atoms repel each other. Strong enough attraction between bosonic and fermionic components can change the character of the interaction within the bosonic cloud from repulsive to attractive making thus possible the generation of bright solitons in the mixture. On the other hand, such structures might be in danger due to the collapse phenomenon existing in attractive gases. We show, however, that under some conditions (defined by the strength of the Bose-Fermi components attraction) the structures which neither spread nor collapse can be generated. For elongated enough traps the formation of solitons is possible even at the ``natural'' value of the mutual Bose-Fermi ($^{87}$Rb -$^{40}$K in our case) scattering length.Comment: 6 pages, 6 figures, 1 tabl

Black soliton in a quasi-one-dimensional trapped fermion-fermion mixture

Employing a time-dependent mean-field-hydrodynamic model we study the generation of black solitons in a degenerate fermion-fermion mixture in a cigar-shaped geometry using variational and numerical solutions. The black soliton is found to be the first stationary vibrational excitation of the system and is considered to be a nonlinear continuation of the vibrational excitation of the harmonic oscillator state. We illustrate the stationary nature of the black soliton, by studying different perturbations on it after its formation.Comment: 7 pages, 10 figure

Free expansion of fermionic dark solitons in a boson-fermion mixture

We use a time-dependent dynamical mean-field-hydrodynamic model to study the formation of fermionic dark solitons in a trapped degenerate fermi gas mixed with a Bose-Einstein condensate in a harmonic as well as a periodic optical-lattice potential. The dark soliton with a "notch" in the probability density with a zero at the minimum is simulated numerically as a nonlinear continuation of the first vibrational excitation of the linear mean-field-hydrodynamic equations, as suggested recently for pure bosons. We study the free expansion of these dark solitons as well as the consequent increase in the size of their central notch and discuss the possibility of experimental observation of the notch after free expansion.Comment: 14 pages, 6 figure

Peculiarities of the distribution of assimilates in the organs of Schisandra chinensis plants under different soil and climatic conditions

Peculiarities of accumulation of nutrients in the leaves of Schisandra chinensis (Turcz.) Baill. and rhizosphere soil under the conditions of its continuous monoculture have been studied. Comparative analysis of the distribution of nutrients in the leaves of plants under different soil and climatic conditions revealed significant differences. It was found that plants grown on podzolic chernozem of Kolomyia State Forest Fund (Otyniia, Ukraine) were characterized by more intensive absorption of such nutrients as Ca, Si, P, Cu, Zn and Mg. The content of P, K, S, Mn was much higher in the foliar tissues of S. chinensis plants cultivated on the territory of the M. Gryshko National Botanical Garden (Kyiv, Ukraine) in the conditions of dark grey forest soil. The high ability of plants to accumulate and release Mg into the rhizosphere soil was revealed, which is fully consistent with the selective ability of plants to release mineral elements into the soil environment in accordance with their ecomorphotypes. At the same time, the amount of Ca in the rhizosphere soil decreased significantly at the end of the vegetative period, which could be explained, on the one hand, by the intensive influx of Ca into plant tissues and, on the other hand, by participation in chemical balancing processes to reduce manganese and nitrogen mobility in the soil. Barrier-free accumulation of Fe, Ca, Mg, Al elements in S. chinensis leaves was revealed, which should be taken into account when developing plant cultivation technology. The studies of allelopathy activity of vegetative and generative organs of plants and rhizosphere soil have shown that phenolic substances accumulate in small amounts in the soil under S. chinensis, which is a prerequisite for successful cultivation of this fruit vine in the Forest-Steppe zone of Ukraine under conditions of continuous long-term cultivation. The largest amount of phenolic substances was in the upper soil horizons, which gradually decreased with depth, which is consistent with the course of redox processes for the studied soil profiles. The pool of free amino acids of S. chinensis plants growing in different soil and climatic conditions was analyzed, the concentration of amino acids in the leaves was the most indicative. Evaluation of the quantitative and qualitative distribution of free amino acids in plant tissues serves as a diagnostic sign of plant sensitivity to soil and climatic conditions

The Impact of Nutritional Quality on the Students’ Health

Aim: To study the nutritional quality and its impact on the health of the students of higher education institutions. Material and methods: 647 students were interviewed. A questionnaire, which contains 17 questions and is aimed at studying the quality of students’ nutrition, was created by authors. Experimental (EG, n = 60) and control (CG, n = 60) groups were formed. The EG included the students whose diet was rational while studying, the CG included the students whose diet was irrational. The level of students’ health was examined at the end of studying according to the methodology of professor G.L. Apanasenko. Results: It was found that only 30.6% of students ate 3-4 times a day, 14.4% – twice a day, 49.8% did not follow any dietary regimen, and 7.9% of students would not eat breakfast at al 43.7% of male students and 53.3% of female students did not follow a dietary regimen at all. A comparative analysis of the physical health of students of EG and CG showed that among both male and female students, the students whose diet was rational had significantly better (p<0.001) level of health. Conclusions: It was determined that the majority of students had low nutritional quality while studying: nutrition was irrational, incomplete, and not varied. This does not contribute to a healthy lifestyle of modern students and can negatively affect the efficiency of their future professional activities

More than a method? Organisational ethnography as a way of imagining the social

© 2016 Informa UK Limited, trading as Taylor & Francis Group. The authors–two anthropologists and an organisational theorist, all organisational ethnographers–discuss their understanding and practices of organisational ethnography (OE) as a way of imagining and reflect on how similar this understanding may be for young organisational researchers and students in particular. The discussion leads to the conclusion that OE may be regarded as a methodology but that it has a much greater potential when it is reclaiming its roots: to become a mode of doing social science on the meso-level. The discussion is based on an analysis of both historical material and the contemporary learning experiences of teaching OE as more than a method to our students

Computer syndrome and its prevention

У статті розглядається вплив комп’ютера на здоров’я людини, виявляється, що він спричиняється такими синдромами: комп’ютерний зоровий - є основним, до якого входить комплекс різних виявів зорової втоми, що безпосередньо пов’язано з роботою; синдром зап’ясткового каналу (карпальний тунельний синдром); хребтовий комп’ютерний синдром; дихальний( грудний) комп’ютерний синдром. У статті відзначається декілька чинників ризику впливу комп’ютера на здоров’я проблеми пов’язані з електромагнітними випромінюваннями; проблеми зору, проблеми погіршення здоров’я пов’язані з м’язами й суглобами стрес депресія й інші нервові розлади, викликані впливом комп’ютера на психіку людини.Треба зазначити, що більшість цих проблем можна достатньо легко уникнути, якщо застосувати запобіжні заходи, зокрема, організація робочого місця користувачем персонального комп’ютера (ПК), особливо дитини, які передбачають обов’язкову наявність таких технічних засобів: комп’ютерного стола з регулюючою платформою для клавіатури; спеціального стола з регулюванням висоти і кута нахилу спинки; довгого кабеля для вільного пересування клавіатури; рідкокристалічного монітора з діагоналлю 17-19 дюймів; нахилено-шарнірної підставки для встановлення екрану під потрібним кутом; вертикальної підставки для укріплення копірувальних текстів, що дозволяє користувачеві переводити погляд від екрану на поверхню стола та зворотному напрямку, тобто здійснювати пристосувальні ( акомодаційні) стрибки. Звертається увага, щоб дитина правильно сиділа за комп’ютерним столом, зокрема, вимоги гігієни такі: ноги повинні бути зігнуті під прямим кутом і впиратися на підлогу; спинка стільця повинна підтримувати нижню половину спини; голову треба тримати прямо з незначним нахилом допереду; верхній край монітора повинен знаходитися на рівні очей і бути на віддалі від них на 60-80 см; для роботи з клавіатурою руки повинні лежати вільно на столі, плечі перебувати злегка у вільному стані. У статі зазначено, що складність проблеми ще й тому, що вищеописані комп’ютерні синдроми можуть виявлятися приховано для користувача(ПК) патологічними процесами з порушеннями функціональних й морфологічних систем організму, тому досить актуальним є своєчасна нейтралізація і профілактика їх виникнення.This article examines the impact of computer on human health, it turns out that it is called the following syndromes: computer eye - is the primary, which includes a set of different manifestations of visual fatigue is directly related to the work; carpal tunnel syndrome (carpal tunnel syndrome); Vertebral computer syndrome; respiratory (chest) computer syndrome. The article notes several risk factors on the health effects of computer problems associated with electromagnetic radiation; vision problems, problems of ill health associated with muscles and joints stress depression and other neurological disorders caused by the influence of the computer on the human psyche, it should be noted that most of these problems can be quite easily avoided if you take precautions, in particular, the organization of the workplace personal user computer (PC), especially a child, which provide for mandatory availability of such technologies:computer desk with adjustable platform for keyboard; special table with adjustable height and backrest angle; cable length for the free movement of the keyboard; LCD monitor with a diagonal of 17-19 inches; tilt-hinge stand for mounting the screen to the desired angle; Vertical Stand for strengthening the copier tions texts, allows the user to translate the look of the screen on the surface of the table back and forth, that is, to carry out adaptive (accommodative) jumps. Attention is paid to the child correctly sitting at a computer desk, in particular, hygiene requirements are: legs should be bent at a right angle and level with the floor; back of the chair should support your lower half of the back; the head should be kept straight with a slight slope in front; the upper edge of the monitor should be at eye level, and be at a distance from them at 60 to 80 cm; to work with the keyboard hands should be resting on the table, his shoulders slightly in a free state. The article pointed out that the complexity of the problem is also because the above-described computer syndromes may appear hidden to the user (PC) pathological processes with impaired functional and morphological systems of the body, so it is highly relevant is the timely neutralization and prevention of their occurrence