Conservation laws of semidiscrete canonical Hamiltonian equations

There are many evolution partial differential equations which can be cast into Hamiltonian form. Conservation laws of these equations are related to one-parameter Hamiltonian symmetries admitted by the PDEs. The same result holds for semidiscrete Hamiltonian equations. In this paper we consider semidiscrete canonical Hamiltonian equations. Using symmetries, we find conservation laws for the semidiscretized nonlinear wave equation and Schrodinger equation.Comment: 19 pages, 2 table

Kinetics of exciton photoluminescence in type-II semiconductor superlattices

The exciton decay rate at a rough interface in type-II semiconductor superlattices is investigated. It is shown that the possibility of recombination of indirect excitons at a plane interface essentially affects kinetics of the exciton photoluminescence at a rough interface. This happens because of strong correlation between the exciton recombination at the plane interface and at the roughness. Expressions that relate the parameters of the luminescence kinetics with statistical characteristics of the rough interface are obtained. The mean height and length of roughnesses in GaAs/AlAs superlattices are estimated from the experimental data.Comment: 3 PostScript figure

Dressing with Control: using integrability to generate desired solutions to Einstein's equations

21 pages, no figures21 pages, no figures21 pages, no figures21 pages, no figuresMotivated by integrability of the sine-Gordon equation, we investigate a technique for constructing desired solutions to Einstein's equations by combining a dressing technique with a control-theory approach. After reviewing classical integrability, we recall two well-known Killing field reductions of Einstein's equations, unify them using a harmonic map formulation, and state two results on the integrability of the equations and solvability of the dressing system. The resulting algorithm is then combined with an asymptotic analysis to produce constraints on the degrees of freedom arising in the solution-generation mechanism. The approach is carried out explicitly for the Einstein vacuum equations. Applications of the technique to other geometric field theories are also discussed

Globular Clusters as Candidates for Gravitational Lenses to Explain Quasar-Galaxy Associations

We argue that globular clusters (GCs) are good candidates for gravitational lenses in explaining quasar-galaxy associations. The catalog of associations (Bukhmastova 2001) compiled from the LEDA catalog of galaxies (Paturel 1997) and from the catalog of quasars (Veron-Cetty and Veron 1998) is used. Based on the new catalog containing 8382 pairs, we show that one might expect an increased number of GCs around irregular galaxies of types 9 and 10 from the hypothesis that distant compact sources are gravitationally lensed by GCs in the halos of foreground galaxies. The King model is used to determine the central surface densities of 135 GCs in the Milky Way. The distribution of GCs in central surface density was found to be lognormal.Comment: 22 pages, 4 figure

Darboux transformations, finite reduction groups and related Yang-Baxter maps

In this paper we construct Yang-Baxter (YB) maps using Darboux matrices which are invariant under the action of finite reduction groups. We present 6-dimensional YB maps corresponding to Darboux transformations for the Nonlinear Schr\"odinger (NLS) equation and the derivative Nonlinear Schr\"odinger (DNLS) equation. These YB maps can be restricted to $4-$dimensional YB maps on invariant leaves. The former are completely integrable and they also have applications to a recent theory of maps preserving functions with symmetries \cite{Allan-Pavlos}. We give a $6-$ dimensional YB-map corresponding to the Darboux transformation for a deformation of the DNLS equation. We also consider vector generalisations of the YB maps corresponding to the NLS and DNLS equation.Comment: 18 pages, revised version. The format of the paper has changed, we added one sectio

Extended parametric resonances in nonlinear Schrodinger systems

We study an example of exact parametric resonance in a extended system ruled by nonlinear partial differential equations of nonlinear Schr\"odinger type. It is also conjectured how related models not exactly solvable should behave in the same way. The results have applicability in recent experiments in Bose-Einstein condensation and to classical problems in Nonlinear Optics.Comment: 1 figur

Данные мониторинга суицидальных попыток и завершенных суицидов в г. Одессе за период 2001-2011 гг.

Статья посвящена анализу суицидальной активности населения миллионного города. Данные многолетнего мониторинга позволяют выявить совпадающую динамику уровней суицидальных попыток и самоубийств в течение 11 лет наблюдения (2001-2011 гг.). Выявлены типичные различия между мужчинами и женщинами (преобладание попыток среди женщин и завершенных самоубийств среди мужчин). Способы попыток и суицидов свидетельствуют о том, что мужчины используют более агрессивные методы самоповреждения. В последние годы наблюдается рост самоубийств среди мужчин в возрастной группе 25-29 лет.The study deals with the suicidal activity of the population of a million city. Long-lasting monitoring data revealed very similar changes of attempted and completed suicides rates over 11 years of monitoring. Rather typical differences between males and females suicidal behaviors are found: higher attempts rates in females and higher completed suicides in males. Methods of attempts and suicides testify that males choose more violent means. During last period growingsuicides are registered in males aged 25-29 years

Bose--Einstein solitons in highly asymmetric traps

We obtain analytic solutions to the Gross-Pitaevskii equation with negative scattering length in highly asymmetric traps. We find that in these traps the Bose--Einstein condensates behave like quasiparticles and do not expand when the trapping in one direction is eliminated. The results can be applicable to the control of the motion of Bose--Einstein condensates.Comment: 12 pages, Latex, Figures available under request on [email protected]

К решению проблем ведения пациентов с гепатоцеллюлярной карциномой (ГЦК). Консенсус экспертов Сибири и Дальнего Востока

.Этапами подготовки консенсуса были два научных медицинских мероприятия с участием ведущих специалистов по гепатоцеллюлярной карциноме (ГЦК) сибирских и дальневосточных регионов. Междисциплинарный совет экспертов «Организация медицинской помощи пациентам с ГЦК и пациентам групп риска ее развития в Новосибирской области (НСО)», с веб-подключением специалистов Иркутского областного онкологического диспансера состоялся 24 сентября 2020 г. В рамках проекта долгосрочного научного сотрудничества Eisai Virtual Oncology Key Experts Academy (EVOKE-Academy) «Гепатоцеллюлярная карцинома» 30 сентября 2021 г. проведено Межрегиональное совещание экспертов Сибири и Дальнего Востока