Compacton existence and spin-orbit density dependence in Bose-Einstein condensates.

We demonstrate the existence of compactons matter waves in binary mixtures of Bose-Einstein condensates (BEC) trapped in deep optical lattices (OL) subjected to equal contributions of intraspecies Rashba and Dresselhaus spin-orbit coupling (SOC) under periodic time modulations of the intraspecies scattering length. We show that these modulations lead to a rescaling of the SOC parameters that involves the density imbalance of the two components. This gives rise to density dependent SOC parameters that strongly influence the existence and the stability of compacton matter waves.

Matter waves in atomic-molecular condensates with Feshbach resonance management.

The dynamics of matter waves in the atomic to molecular condensate transition with a time-modulated atomic scattering length is investigated. Both the cases of rapid and slow modulations are studied. In the case of rapid modulations, the average over oscillations for the system is derived.

Variational approximation for two-dimensional quantum droplets.

The dynamics of a two-dimensional Bose-Einstein condensate in a presence of quantum fluctuations is studied. The properties of localized density distributions, quantum droplets (QDs), are analyzed by means of the variational approach. It is demonstrated that the super-Gaussian function gives a good approximation for profiles of fundamental QDs and droplets with nonzero vorticity.

[Correction of urethral stenosis after proximal hypospadias repair in children].

Aim: Urethral stenosis is one of the serious complications after proximal hypospadias repair. A variety of techniques has been suggested for its correction, such as urethral dilation using bougies, endoscopic incisions and one- or two-staged urethroplasty with buccal mucosa. The aim of our study was to improve results of urethral stenosis correction in children after multiple proximal hypospadias repairs.

[Comparative histological analysis of different materials used for urethroplasty in children with proximal forms of hypospadias: preputial skin vs buccal mucosa].

Aim: Buccal mucosa and preputial skin grafts are used for staged urethroplasty in proximal forms of hypospadias in children. Aim of our study was to carry out a comparative histological analysis of preputial skin and buccal mucosa.

Method: s and materials: Histological analysis of urethral tissue samples from 10 patients with proximal forms of hypospadias was conducted.

Dissipative solitons in the discrete Ginzburg-Landau equation with saturable nonlinearity.

The modulational instability of nonlinear plane waves and the existence of periodic and localized dissipative solitons and waves of the discrete Ginzburg-Landau equation with saturable nonlinearity are investigated. Explicit analytic expressions for periodic solutions with a zero and a finite background are derived and their stability properties investigated by means of direct numerical simulations. We find that while discrete periodic waves and solitons on a zero background are stable under time evolution, they may become modulationally unstable on finite backgrounds.

[Aesthetic criteria in surgical treatment of hypospadias in children].

Unlabelled: Aesthetically acceptable cosmetic results of surgical correction of external genital organ defects are important for treatment evaluation along with well-known criteria of good functional outcomes.The purpose of this study was to improve the results of treating children with hypospadias by improving the assessment of results and introducing multi-step correction modalities.

Materials And Methods: From 2013 to 2015, 476 patients with various forms of hypospadias were treated at the Department of Uroandrology of RCCH.

Solitons in a PT-symmetric χ coupler.

We consider the existence and stability of solitons in a χ coupler. Both the fundamental and second harmonics (SHs) undergo gain in one of the coupler cores and are absorbed in the other one. The gain and loss are balanced, creating a parity-time (PT) symmetric configuration.

Stable localized modes in asymmetric waveguides with gain and loss.

It is shown that asymmetric waveguides with gain and loss can support a stable propagation of optical beams. This means that the propagation constants of modes of the corresponding complex optical potential are real. A class of such waveguides is found from a relation between two spectral problems.

Gap solitons in a spin-orbit-coupled Bose-Einstein condensate.

We report a diversity of stable gap solitons in a spin-orbit-coupled Bose-Einstein condensate subject to a spatially periodic Zeeman field. It is shown that the solitons can be classified by the main physical symmetries they obey, i.e.

[Efficiency of endoscopic treatment of primary vesicoureteral reflux depending on bulking agent].

From June 1991 to December 2011, endoscopic treatment of vesicoureteral reflux (VUR) was performed more than in 4,000 children aged 4 months to 17 years. As bulking agents, teflon paste, DAM +, urodex, and vantris were used. A comparative evaluation of the effectiveness of single endoplasty with various bulking agents in children with I-V degree primary VUR, who had no gross congenital abnormalities in ureterovesical anastomosis, such as paraureteral diverticula, complete duplicated ureter or extravesicalisation of ureter, and not suffered from chronic cystitis, was performed.

Discrete solitons in arrays of positive and negative index waveguides.

We report on existence and properties of discrete solitons in arrays of alternating waveguides with positive and negative refractive indices. When the nonlinearities of all waveguides are focusing, we found solitons only in the semi-infinite gaps. Finite gap solitons found for waveguides having nonlinearities of different types reveal the symmetry breaking in the Fourier space.

Zeno effect and switching of solitons in nonlinear couplers.

The Zeno effect is investigated for soliton type pulses in a nonlinear directional coupler with dissipation. The effect consists in increase of the coupler transparency with increase of the dissipative losses in one of the arms. It is shown that localized dissipation can lead to switching of solitons between the arms.

[Urinary bladder hemangiomas in children: experience with endoscopic treatment].

Urgent arrest of bleeding is often required in hemangiomas. Endoscopic photocoagulation with Ne YAG-laser was applied in the department of urology of the Central Children's Hospital in Moscow to arrest bleeding in 5 children (2 boys and 3 girls aged 3-12 years) with hemangioma of the bladder in 1998-2009. In 3 cases the tumors were solitary (up to 5 cm), in 2 cases (multiple small 1-3 cm).

Dissipative periodic waves, solitons, and breathers of the nonlinear Schrödinger equation with complex potentials.

Exact solutions for the generalized nonlinear Schrödinger equation with inhomogeneous complex linear and nonlinear potentials are found. We have found localized and periodic solutions for a wide class of localized and periodic modulations in the space of complex potentials and nonlinearity coefficients. Examples of stable and unstable solutions are given.

Compactons in nonlinear Schrödinger lattices with strong nonlinearity management.

The existence of compactons in the discrete nonlinear Schrödinger equation in the presence of fast periodic time modulations of the nonlinearity is demonstrated. In the averaged discrete nonlinear Schrödinger equation, the resulting effective interwell tunneling depends on the modulation parameters and on the field amplitude. This introduces nonlinear dispersion in the system and can lead to a prototypical realization of single- or multisite stable discrete compactons in nonlinear optical waveguide and Bose-Einstein condensate arrays.

Soliton dynamics at an interface between a uniform medium and a nonlinear optical lattice.

We study trapping and propagation of a matter-wave soliton through the interface between uniform medium and a nonlinear optical lattice. Different regimes for transmission of a broad and a narrow solitons are investigated. Reflections and transmissions of solitons are predicted as a function of the lattice phase.

[Endoscopic electroexcision of benign urethral tumors in children].

Endoscopic treatment was performed in 17 boys aged 4 months-16 years with benign new growths of the posterior urethra: false polyps (n = 11), fibroepithelial polyps (congenital--4, acquired--1), fetal rabdomyoma of the urethra and urinary bladder (n = 1). Acquired fibroepithelial polyp was detected in a patient who previously had resection and urethral anastomosis for posttraumatic stricture and long-term preventive catheterization. A leading symptom of the disease in 8 patients was infravesical obstruction.

Generalized neighbor-interaction models induced by nonlinear lattices.

It is shown that the tight-binding approximation of the nonlinear Schrödinger equation with a periodic linear potential and periodic in space nonlinearity coefficient gives rise to a number of nonlinear lattices with complex, both linear and nonlinear, neighbor interactions. The obtained lattices present nonstandard possibilities, among which we mention a quasilinear regime, where the pulse dynamics obeys essentially the linear Schrödinger equation. We analyze the properties of such models both in connection to their modulational stability, as well as in regard to the existence and stability of their localized solitary wave solutions.

Disintegration of a soliton in a dispersion-managed optical communication line with random parameters.

The propagation of dispersion-managed solitons in optical fiber links with a random dispersion map has been studied. Two types of randomness are considered:random dispersion magnitudes and random lengths of the spans. By numerical simulations, disintegration of a soliton propagating in such an optical communication line is shown to occur.

Solitons in strongly driven discrete nonlinear Schrödinger-type models.

Discrete solitons in the Ablowitz-Ladik (AL) and discrete nonlinear Schrödinger (DNLS) equations with damping and strong rapid drive are investigated. The averaged equations have the forms of the parametric AL and DNLS equations. An additional type of parametric bright discrete soliton and cnoidal waves are found and the stability properties are analyzed.

Dynamical stabilization of solitons in cubic-quintic nonlinear Schrödinger model.

We consider the existence of a dynamically stable soliton in the one-dimensional cubic-quintic nonlinear Schrödinger model with strong cubic nonlinearity management for periodic and random modulations. We show that the predictions of the averaged cubic-quintic nonlinear Schrödinger (NLS) equation and modified variational approach for the arrest of collapse coincide. The analytical results are confirmed by numerical simulations of a one-dimensional cubic-quintic NLS equation with a rapidly and strongly varying cubic nonlinearity coefficient.

Ising-Bloch transition for the parametric Ginzburg-Landau equation with rapidly varying perturbations.

We study the effects of rapid periodic and stochastic modulations of parameters in systems described by the complex parametric Ginzburg-Landau equation. Amplitude equations, which govern the dynamics of the field averaged over the rapid modulations, are derived. For temporal modulations of the linear detuning the threshold for the transition from Ising to Bloch walls is shifted depending on the strength of the perturbation.

Stable two-dimensional dispersion-managed soliton.

The existence of a dispersion-managed soliton in two-dimensional nonlinear Schrödinger equation with periodically varying dispersion has been explored. The averaged equations for the soliton width and chirp are obtained which successfully describe the long time evolution of the soliton. The slow dynamics of the soliton around the fixed points for the width and chirp are investigated and the corresponding frequencies are calculated.

Adiabatic dynamics of periodic waves in Bose-Einstein condensates with time dependent atomic scattering length.

Evolution of periodic matter waves in one-dimensional Bose-Einstein condensates with time-dependent scattering length is described. It is shown that variation of the effective nonlinearity is a powerful tool for controlled generation of bright and dark solitons starting with periodic waves.