Dynamics of bright matter wave solitons in a quasi 1D Bose-Einstein condensate with a rapidly varying trap

The dynamics of a bright matter wave soliton in a quasi 1D Bose-Einstein condensate with periodically rapidly varying trap is considered. The governing equation is derived based on averaging over fast modulations of the Gross-Pitaevskii (GP) equation. This equation has the form of GP equation with effective potential of more complicated structure than unperturbed trap. For the case of inverted (expulsive) quadratic trap corresponding to unstable GP equation, the effective potential can be stable. For the bounded in space trap potential it is showed that the bifurcation exists, i.e.,the single well potential bifurcates to the triple well effective potential. Stabilization of BEC cloud on-site state in the temporary modulated optical lattice is found. (analogous to the Kapitza stabilization of the pendulum). The predictions of the averaged GP equation are confirmed by the numerical simulations of GP equation with rapid perturbations.Comment: 15 pages, 4 figure

The System of Sociocultural Adaptation of Foreign Students at Leading Russian Universities (On the Example of Azerbaijani and Chinese Students)

The number of foreign students educating in Russian universities is increasing every year. With the growing number of such students, the issue of their adaptation becomes more re levant, because that adaptation also determines the success of education. The substantial role in this process falls to the share of universities and their educational system, which in the initial stages is aimed at accelerating the adaptation of foreign students to everyday life in Russia, also to provide high-quality and promising education.The article presents the results of a study conducted in order to investigate the features of sociocultural adaptation, the difficulties, which are faced by students during their education period and their expectations, coverage of the place and role of universities, therefore, and scientific and pedagogical staff. To achieve an accurate result, we conducted a survey of international students from the Republic of Azerbaijan and the People’s Republic of China studying at Russian universities. 107 students in total (45% Azerbaijani students and 55% Chinese students) from leading Moscow universities participated in the questionnaire-based survey, the age cohort of respondents ranged from 21 to 35 years. Analysis of the results of the survey made it possible to determine the main types of adaptation of students to identify objective and subjective factors of sociocultural adaptation, to compare the principal features of foreign students from Azerbaijan and China in order to understand the main problems of intercultural communication of students from different ethnic groups. The relevance and uniqueness of the study are based on cross-cultural differences between the studied groups, which made it possible to identify both principal and specific features, and their significant difference from Russian culture.The authors of the article concluded that the acceleration of the process of sociocultural adaptation is possible, first of all, through the study of the Russian language and pre-departure training in their homeland, which includes studying of Russian culture, history, traditions and specifics of intercultural communication. Based on the results of the study, the authors proposed recommendations for the formation of a system of measures aimed to optimize the processes of sociocultural adaptation, including well-organized training and teaching, as well as involvement of foreign students in the social activities of the university

Controlling collapse in Bose-Einstein condensates by temporal modulation of the scattering length

We consider, by means of the variational approximation (VA) and direct numerical simulations of the Gross-Pitaevskii (GP) equation, the dynamics of 2D and 3D condensates with a scattering length containing constant and harmonically varying parts, which can be achieved with an ac magnetic field tuned to the Feshbach resonance. For a rapid time modulation, we develop an approach based on the direct averaging of the GP equation,without using the VA. In the 2D case, both VA and direct simulations, as well as the averaging method, reveal the existence of stable self-confined condensates without an external trap, in agreement with qualitatively similar results recently reported for spatial solitons in nonlinear optics. In the 3D case, the VA again predicts the existence of a stable self-confined condensate without a trap. In this case, direct simulations demonstrate that the stability is limited in time, eventually switching into collapse, even though the constant part of the scattering length is positive (but not too large). Thus a spatially uniform ac magnetic field, resonantly tuned to control the scattering length, may play the role of an effective trap confining the condensate, and sometimes causing its collapse.Comment: 7 figure

SPECIFIC FEATURES OF SYSTEM INFLAMMATORY RESPONSE SYNDROME AND NUTRITIONAL STATUS IN PULMONARY TUBERCULOSIS PATIENTS WITH CONCURRENT TYPE 1 AND 2 DIABETES

45 pulmonary tuberculosis patients with concurrent type 1 diabetes, 69 pulmonary tuberculosis patients with concurrent type 2 diabetes and 131 pulmonary tuberculosis patients without diabetes (control group) were examined. The intensity of the system inflammatory response syndrome was evaluated by the markers of the acute inflammation phase – blood levels of C-reactive protein (CRP), serum amyloid A (SAA), α1 -antitrypsin (α1 -АТ), haptoglobin, and fibrinogen. Nutritional status was assessed by body mass index (BMI) and concentration of total protein (TP), albumin (A), and transthyretin (TTR). It was found out that in new progressing forms in pulmonary tuberculosis patients with concurrent diabetes the mobilisation of acute phase proteins responsible for early anti-infection protection (CRP, SAA) was less expressed compared to the patients without concurrent diabetes. On the contrary in torpent forms of the disease CRP and SAA were much higher in those with concurrent conditions compared to the patients without concurrent diabetes. The reaction of acute phase proteins in new cases and infiltrate and pneumonic forms of the disease was more severe in those with concurrent type 1 diabetes and more moderate and slow in case of type 2 diabetes. Nutritional status in the patients with concurrent conditions differed greatly from patients in the control group. With no concurrent diabetes all signs of nutritional deficiency (low BMI, A and TTR) promoted the severe course of the disease. TP remained within normal limits. Patients with concurrent diabetes demonstrated reduction TP and TTR, but BMI and A remained normal in case of type 1 diabetes and increased in type 2 diabetes. Ratio of albumins/globulins (A/G) went down in the control group but tended to increase in case of concurrent diabetes. According to correlation analysis the reduction of TP in the patients with concurrent condition was not due to A but globulins. Shifts fundamentally different for patients with concurrent diabetes and those without concurrent diabetes (increase of BMI, A, A/G) were much greater expressed in type 2 diabetes and manifestations of protein-energy deficiency (decrease of TP and TTR) were more intensive in type 1 diabetes

Modulational and Parametric Instabilities of the Discrete Nonlinear Schr\"odinger Equation

We examine the modulational and parametric instabilities arising in a non-autonomous, discrete nonlinear Schr{\"o}dinger equation setting. The principal motivation for our study stems from the dynamics of Bose-Einstein condensates trapped in a deep optical lattice. We find that under periodic variations of the heights of the interwell barriers (or equivalently of the scattering length), additionally to the modulational instability, a window of parametric instability becomes available to the system. We explore this instability through multiple-scale analysis and identify it numerically. Its principal dynamical characteristic is that, typically, it develops over much larger times than the modulational instability, a feature that is qualitatively justified by comparison of the corresponding instability growth rates

Painlev\'{e} test of coupled Gross-Pitaevskii equations

Painlev\'{e} test of the coupled Gross-Pitaevskii equations has been carried out with the result that the coupled equations pass the P-test only if a special relation containing system parameters (masses, scattering lengths) is satisfied. Computer algebra is applied to evaluate j=4 compatibility condition for admissible external potentials. Appearance of an arbitrary real potential embedded in the external potentials is shown to be the consequence of the coupling. Connection with recent experiments related to stability of two-component Bose-Einstein condensates of Rb atoms is discussed.Comment: 13 pages, no figure

Компоненты системы "протеиназы–антипротеиназы" в индуцированной мокроте больных хронической обструктивной болезнью легких

Summary. Results of investigation of protease–antiprotease enzyme activity in induced sputum of patients with chronic obstructive pulmonary disease (COPD) are presented in this article. In addition to infection, inflammation severity during acute exacerbation of COPD was shown to be influenced by smoking and protease–antiprotease biochemical imbalance, in particular, by the level of α1protease inhibitor which regulates proteolytic enzyme activity.Резюме. В статье представлены результаты анализа активности ферментов системы "протеиназы–антипротеиназы", изученных в индуцированной мокроте больных хронической обструктивной болезнью легких (ХОБЛ). Показано, что на выраженность воспаления при обострении ХОБЛ, помимо инфекционного фактора, влияют курение и дисбаланс в биохимической системе "протеиназы–антипротеиназы", в частности уровень α1протеиназного ингибитора в индуцированной мокроте больных, регулирующего активность протеолитических ферментов

Кислородзависимый метаболизм и синтез фактора активации тромбоцитов в разных типах фагоцитирующих клеток у морских свинок при естественном течении экспериментального туберкулеза и в условиях специфической химиотерапии

Summary cell sediment (SCS) and aiveolar macrophages (AM ) pure fraction were isolated from bronchoalveolar lavage fluid (BALF) and leucocytes which were neutrophyles by 85— 89% were isolated from blood of 108 infected with tuberculosis guinea pigs in various terms of natural trend of experimental tuberculosis and after chemo therapy course. All the ceil samples were tested by spontaneous and stimulated test with nitrogen blue tetrazolinium in order to determine superoxide dismutase and catalase activity, malondialdehyde and thrombocytes activation factor (TAF) content. Eighteen healthy animals formed the control group. It was found that after in sertion of pathogen alveolar macro phages of pure fraction went to maxim umirritation , then became decompensated rapidly and then, in the terminal period of infection, they began working for self-preservation and increased the activity of antioxidant protection enzymes multiply. SCS bactericidal potential was kept longer, but AM and SCS values were equivalent in the terminal period. Blood neutrophyles bactericidal potential was kept during the whole infectious process. TAF level of SCS and neutrophyles increased sharply in infected animals, but it enlarged only for a short time in isolated AM. All the revealed changes were smoothed out in various degrees after chemotherapy course.У 108 зараженных туберкулезом морских свинок в разные сроки естественного течения экспериментального туберкулеза и после курса химиотерапии (ХТ) из бронхиального смыва (БАС) выделяли суммарный клеточный осадок (СКО) и чистую фракцию альвеолярных макрофагов (АМ), из крови—лейкоциты, среди которых 85—89% составляли нейтрофилы (Н). Во всех образцах клеток ставили спонтанный и стимулированный тест с нитросиним тетразолием, определяли активность супероксиддисмутазы и ка-талазы, а также содержание малонового диальдегида и фактора активации тромбоцитов (ФАТ). Контроль составили 18 здоровых животных. Установлено, что АМ в чистой фракции сразу после введения возбудителя приходили в состояние максимального раздражения, затем быстро декомпенсироваись, а в терминальный период инфекции начинали работать на самосохранение, многократно увеличивая активность ферментовантиоксидантной защиты. ВСКО бактерицидный потенциал сохранялся более длительно, но в терминальный период показатели АМ и СКО были аналогичными. ВН крови бактерицидный потенциал сохранялся на протяжении всего инфекционного процесса. Уровень ФАТ резко возрастал в СКО и Н зараженных животных, но лишь кратковременно увеличивался в изолированных АМ. После курса ХТ все выявленные изменения в разной степени нивелировались

Electronic energy band parameters of CuInSe2 : Landau levels in magnetotransmission spectra

Magnetotransmission (MT) at magnetic fields up to 29 T was used to study the electronic structure of CuInSe2 in thin polycrystalline films. The zero field absorption spectra exhibited resolved A, B, and C free excitons. Quantum oscillations, due to diamagnetic excitons comprising electrons and holes from Landau levels quantized in the conduction and valence band, respectively, appeared in the MT spectra at fields over 5 T. Spectral energies of Landau levels and binding energies of the corresponding diamagnetic excitons, theoretically calculated assuming a quasicubic approximation of the CuInSe2 tetragonal lattice structure, helped to identify the character of the experimentally observed diamagnetic excitons. Spectral energies of diamagnetic excitons in the MT spectra with different circular polarizations were used to determine the electron and light hole effective masses, whereas heavy hole masses as well as the γ and γ1 Luttinger parameters, Ep Kane energy, and F parameter of the influence of remote bands, as well as their polaron values, were calculated using the Luttinger theory

The Efimov's effect for a model of a three particle discrete Shr\"odinger operator

In the paper we study existance of infinitly many egenvalues for a model of a three particle discrete Shr\"odinger operator.Comment: Russia