Stable multiple-charged localized optical vortices in cubic-quintic nonlinear media

The stability of two-dimensional bright vortex solitons in a media with focusing cubic and defocusing quintic nonlinearities is investigated analytically and numerically. It is proved that above some critical beam powers not only one- and two-charged but also multiple-charged stable vortex solitons do exist. A vortex soliton occurs robust with respect to symmetry-breaking modulational instability in the self-defocusing regime provided that its radial profile becomes flattened, so that a self-trapped wave beam gets a pronounced surface. It is demonstrated that the dynamics of a slightly perturbed stable vortex soliton resembles an oscillation of a liquid stream having a surface tension. Using the idea of sustaining effective surface tension for spatial vortex soliton in a media with competing nonlinearities the explanation of a suppression of the modulational instability is proposed.Comment: 4 pages, 3 figures. Submitted to Journal of Optics A. The proceedings of the workshop NATO ARW, Kiev 2003 Singular Optics 200

New types of stable nonlinear whistler waveguides

International audienceThe stationary self-focusing of whistler waves with frequencies near half of the electron-cyclotron frequency in the ionospheric plasma is considered in the framework of a two-dimensional generalized nonlinear Schrödinger equation including fourth-order dispersion effects and nonlinearity saturation. New types of soliton-like (with zero topological charge) and vortex-like nonlinear waveguides are found, and their stability confirmed both analytically and numerically

Fast recognition of marine particles in underwater digital holography

The issue of fast recognition of marine particles in situ by digital holography methods is considered. An algorithm for the classification of marine particles by morphological features is proposed. Preliminary results and estimation of accuracy of the proposed algorithm are presented

Influence of overload on low-frequency instability of working process in the combustion chamber of the solid propellant rocket engine

In the paper the real oscillatory process is reproduced by statement of direct numerical experiment and the mechanism of occurrence and refill of low-frequency acoustic instability in the combustion chamber of the solid propellant rocket engine with the account of flight overload is investigated for the first time. The direct numerical modeling of low-frequency acoustic instability is carried out by means of Davydov’s method (method of large particles), which is well-suited for the solutions of many problems of mechanics of the continuous media. The results of numerical modeling are presented here. The hydrodynamic highly nonlinear nature of low-frequency fluctuations connected to structure and character of current in the combustion chamber of the rocket engine on firm fuel are proved to be tru

Optimization of the Androgenesis Method in the In Vitro Culture of Anteneson the Basis ofT. AestivumHybrids

This study aimed to examine the regularities of the regenerationprocesses of haploid plants, the dependence of in vitro microspore morphogenesis in anther culture on optimization factors, and their efficiency in F1 hybrids of T. aestivumof different ecological and geographicorigin. It was found that heterosis contributed to an increased yield of haploid chlorophyll-bearing regenerants from hybrids obtained from the crossing of parental forms with different responsiveness to androclinia. Results were obtained for the complex optimization of the androgenesis method for the in vitro anther culture of T. aestivum, in order to create diploidized haploid lines (DHL) regardless of the influence of the genotype. The agroecological properties for a complex of economically useful traits were also assessed. DHLs were created that combined high yield (5.1-6.8 t / ha) with lodging resistance (straw height – 60-80 cm) and consistently high grain quality; these were characterized by increased resistance to major leaf diseases in comparison with the standard variety in the conditions of the Central Economic Region of the Non-Black Earth Zone of the Russian Federation. Keywords: spring soft wheat, androgenesis, embyroidogenesis, callusogenesis, diploidized haploids, in vitro, yield and qualit

Digital holographic camera for plankton monitoring

A submersible digital holographic camera for measuring plankton and other particles is described. The camera provides underwater recording of digital holograms of water volume containing plankton followed by automatic restoration of holographic images of plankton species, determination of their sizes, shapes, and concentrations, and their recognition and classification. Particles with sizes of 200 μm and larger are analyzed. The water volume registered per exposure is about 1 L. The special features of the software for automatic information retrieval from digital holograms are discussed. Examples of application of the camera as an integral part of the hardware-software complex for field measurements are given. Prospects for application of this complex for ecological monitoring are discussed. The recognition criterion of the digital holographic camera and the data volume and the averaging time required for obtaining statistically reliable data on plankton species are also given

Компетенции как фактор комплексной подготовки учителей иностранного языка в педвузе

This article is devoted to the problem of complex training of the specialists studying foreign languages in the Teachers’ Training Institutes. Such notions as «linguopedagogical competence», «communicative competence», «cognitive competence», «creative competence», personal qualities and skills providing successful communication of students studying foreign languages are given attention to in this article.Данная статья посвящена проблеме комплексной подготовки специалиста в области преподавания иностранных языков. В статье рассматриваются такие понятия как лингвопедагогическая компетентность, коммуникативная, когнитивная и креативная компетенции, дается подробное описание личностных качеств, обеспечивающих эффективное взаимодействие учащихся в процессе овладения иноязычной речью и развитие индивидуальных творческих ресурсов

Mathematical model for analyzing the interrelation between monetary circulation and economic growth in developing countries

Objective to develop a basic mathematical model to assess the impact of foreign trade on the national economy and the impact of the national currency on economic growth in relation to developing countries. Methods methods of mathematical dynamic modeling are used in the development of the model. Results one of the most acute and unresolved problems for the Russian economy is the development of such currencymonetary policy that would provide opportunities for economic growth. One of the reasons for the ongoing disputes is the lack of a qualitative mathematical model that allows assessing its impact on economic processes. Mathematical models proposed by representatives of different economic scientifc schools and describing the impact of monetization on the economy are considered. It is determined that the previously developed models are not applicable to the economies of developing countries. The characteristic is given of the dynamic mathematical model earlier developed by the authors describing cash flows in the Russian economy. The importance of models for developing economies is analyzed in terms of growth of the money supply and changes in the exchange rate of the national currency. As a result it is determined that the constructed model which is an aggregate version of the model of switching reproduction takes into account the openness of the national economy and inflation processes. The model is tested on the example of currencymonetary policy of the USA and Russia. Scientific novelty the model differs from analogues in that it is based on the modeling of cash flows in accordance with the methodology of modeling of switching reproduction which allows analyzing the interaction of fnancial and real sectors of economy in developing countries. Practical significance the model allows estimating the consequences of decisions in the feld of currencymonetary policy in developing countries

Stability of two-dimensional spatial solitons in nonlocal nonlinear media

We discuss existence and stability of two-dimensional solitons in media with spatially nonlocal nonlinear response. We show that such systems, which include thermal nonlinearity and dipolar Bose Einstein condensates, may support a variety of stationary localized structures - including rotating spatial solitons. We also demonstrate that the stability of these structures critically depends on the spatial profile of the nonlocal response function.Comment: 8 pages, 9 figure