Deviation from one-dimensionality in stationary properties and collisional dynamics of matter-wave solitons

By means of analytical and numerical methods, we study how the residual three-dimensionality affects dynamics of solitons in an attractive Bose-Einstein condensate loaded into a cigar-shaped trap. Based on an effective 1D Gross-Pitaevskii equation that includes an additional quintic self-focusing term, generated by the tight transverse confinement, we find a family of exact one-soliton solutions and demonstrate stability of the entire family, despite the possibility of collapse in the 1D equation with the quintic self-focusing nonlinearity. Simulating collisions between two solitons in the same setting, we find a critical velocity, $V_{c}$, below which merger of identical in-phase solitons is observed. Dependence of $V_{c}$ on the strength of the transverse confinement and number of atoms in the solitons is predicted by means of the perturbation theory and investigated in direct simulations. Symmetry breaking in collisions of identical solitons with a nonzero phase difference is also shown in simulations and qualitatively explained by means of an analytical approximation.Comment: 10 pages, 7 figure

Changes in the indicators of cardiac pumping function of parachutists before jumping and after landing

© 2016, International Journal of Pharmacy and Technology. All rights reserved.Studying the reaction of the cardiac pumping function of the parachutists at various stages of preparation for jump, we found that, as the athletes develop their skills, the difference between the values of heart rate prior to and after landing decreases significantly. At the same time, the least difference in heart rate values prior to and after landing was recorded in the masters of sports of international class. While the athletes of participation classes and masters of sports have this difference maintained at a high level of nearly 69-70 bpm (P <0.05). The maximum difference in heart rate values prior to and after landing was recorded in ex-masters of sports. As the parachutists upgrade their level of fitness, the stroke volume response, on the contrary, increases. However, we detected a negative stroke volume response for the first time in both the beginners and the ex-masters of sports after the jump

Features of changes in the parameters of heart pumping function and excretion of catecholamines in primary school children when giving the oral answers at theoretical lessons

© 2016, International Journal of Pharmacy and Technology. All rights reserved.It was revealed for the first time that changes in the indices of cardiac pump function of the first graders during oral responses either at a desk or at the blackboard do not depend on the level of physical activity. During the subsequent years of study, the reaction of the heart pumping function of children subjected to enhanced motor activity decreases significantly when giving oral responses at the theoretical lessons. It was found that, from age to age, all children examined have a significant reduction in their stroke volume response when answering at a desk or standing at the blackboard. The reaction of the parameters of heart pumping function of first and fourth graders is slightly higher in boys than in girls. It was found for the first time that the reaction of the parameters of cardiac pumping function in the examined children is lower when answering at the blackboard. It was also revealed that the excretion of adrenaline and noradrenaline during oral responses in the first class does not depend on the level of physical activity. It was found for the first time that the children of control group have greater epinephrine excretion when giving oral answers both at the desk and at the blackboard, while the children with enhanced motor activity have greater excretion of norepinephrine

Matter-wave vortices in cigar-shaped and toroidal waveguides

We study vortical states in a Bose-Einstein condensate (BEC) filling a cigar-shaped trap. An effective one-dimensional (1D) nonpolynomial Schroedinger equation (NPSE) is derived in this setting, for the models with both repulsive and attractive inter-atomic interactions. Analytical formulas for the density profiles are obtained from the NPSE in the case of self-repulsion within the Thomas-Fermi approximation, and in the case of the self-attraction as exact solutions (bright solitons). A crucially important ingredient of the analysis is the comparison of these predictions with direct numerical solutions for the vortex states in the underlying 3D Gross-Pitaevskii equation (GPE). The comparison demonstrates that the NPSE provides for a very accurate approximation, in all the cases, including the prediction of the stability of the bright solitons and collapse threshold for them. In addition to the straight cigar-shaped trap, we also consider a torus-shaped configuration. In that case, we find a threshold for the transition from the axially uniform state, with the transverse intrinsic vorticity, to a symmetry-breaking pattern, due to the instability in the self-attractive BEC filling the circular trap.Comment: 6 pages, Physical Review A, in pres

Symbiotic gap and semi-gap solitons in Bose-Einstein condensates

Using the variational approximation and numerical simulations, we study one-dimensional gap solitons in a binary Bose-Einstein condensate trapped in an optical-lattice potential. We consider the case of inter-species repulsion, while the intra-species interaction may be either repulsive or attractive. Several types of gap solitons are found: symmetric or asymmetric; unsplit or split, if centers of the components coincide or separate; intra-gap (with both chemical potentials falling into a single bandgap) or inter-gap, otherwise. In the case of the intra-species attraction, a smooth transition takes place between solitons in the semi-infinite gap, the ones in the first finite bandgap, and semi-gap solitons (with one component in a bandgap and the other in the semi-infinite gap).Comment: 5 pages, 9 figure

Infl uence of orthostatic test on the heart pumping function in athletes with lower extremities motor disorders

Objective: to study the response of heart pumping function (HPF) of athletes with disabilities to an orthostatic test. Materials and methods: 20 wheelchair athletes (21-30 year-old) were examined. Group I are wheelchair basketball players with amputated lower limbs at the level of the upper third of the tibia. II group - athletes with spinal damage and atrophy of lower limbs at the level of Th 12, L1, with compression, partial rupture of spinal cord, lower limbs paralysis, and small pelvic organ functional disorder. We compared the heart rate (HR) and stroke volume (SV). Th e analysis was carried out in two stages: we take measurements in the lying position and within 5 - 20 seconds aft er an active transition from the lying position to the sitting position. Results: In group I, the HR in the lying position was 77.2±1.4 bpm. With the active change of position, the HR increased by 7.3±1.2 bpm (p&lt;0.05) to 84.5±1.8 bpm. Th e HR in group II in the lying position was 71.3±1.8 bpm. Aft er an active position change, it increased to 75.7±2.1 bpm. Th e HR response to the change of body position in group II was 4.4±1.6 bpm (p&lt;0.05), which was 2.9±1.3 bpm less than the HR response to a change of body position in group I (p&lt;0.05). HR decrease within 4 to 12 bpm may indicate a reduced tone of sympathetic part of vegetative nervous system. Th e SV of group I in the lying position was 54.3±1.6 ml. Aft er active transition from lying position to sitting position, the SV decreased to 45.7±1.9 ml (p&lt;0.05). At transition from lying position to sitting position, the SV reaction in athletes with amputated of lower limbs was 8.6±1.4 ml (p&lt;0.05). In wheelchair basketball players with lower limb atrophy, the SV in lying position was 6.8±1.9 ml and decreased by 4,3±1.7 ml at active transition from lying position to sitting position to 57.5±2.1 ml (p&lt;0.05), which diff ers signifi cantly from the reaction of group I by 4.3±1.6 ml (p&lt;0.05). Conclusions: In group I, the diff erence in HR values in an orthostatic test is signifi cantly higher than in group II

Matter-wave 2D solitons in crossed linear and nonlinear optical lattices

It is demonstrated the existence of multidimensional matter-wave solitons in a crossed optical lattice (OL) with linear OL in the $x-$direction and nonlinear OL (NOL) in the $y-$direction, where the NOL can be generated by a periodic spatial modulation of the scattering length using an optically induced Feshbach resonance. In particular, we show that such crossed linear and nonlinear OL allows to stabilize two-dimensional (2D) solitons against decay or collapse for both attractive and repulsive interactions. The solutions for the soliton stability are investigated analytically, by using a multi-Gaussian variational approach (VA), with the Vakhitov-Kolokolov (VK) necessary criterion for stability; and numerically, by using the relaxation method and direct numerical time integrations of the Gross-Pitaevskii equation (GPE). Very good agreement of the results corresponding to both treatments is observed.Comment: 8 pages (two-column format), with 16 eps-files of 4 figure

Vector solitons in nearly-one-dimensional Bose-Einstein condensates

We derive a system of nonpolynomial Schroedinger equations (NPSEs) for one-dimensional wave functions of two components in a binary self-attractive Bose-Einstein condensate loaded in a cigar-shaped trap. The system is obtained by means of the variational approximation, starting from the coupled 3D Gross-Pitaevskii equations and assuming, as usual, the factorization of 3D wave functions. The system can be obtained in a tractable form under a natural condition of symmetry between the two species. A family of vector (two-component) soliton solutions is constructed. Collisions between orthogonal solitons (ones belonging to the different components) are investigated by means of simulations. The collisions are essentially inelastic. They result in strong excitation of intrinsic vibrations in the solitons, and create a small orthogonal component ("shadow") in each colliding soliton. The collision may initiate collapse, which depends on the mass and velocities of the solitons.Comment: 7 pages, 6 figures; Physical Review A, in pres