Discrete Breathers in Hexagonal Dusty Plasma Lattices

The occurrence of single- or multisite localized vibrational modes, also called Discrete Breathers (DBs), in 2D hexagonal dusty plasma (DP) lattices is investigated. The system is described by a Klein-Gordon hexagonal lattice characterized by a negative coupling parameter \e in account of its inverse dispersive behavior. A theoretical analysis is performed in order to establish the possibility of existence of single- as well as three-site DBs in such systems. The study is complemented by a numerical investigation based on experimentally provided potential forms. This investigation shows that a DP lattice can support single site DBs while three-site in phase breathers could exist if specific conditions, about the inter-grain interaction strength, would hold. On the other hand, out of phase and vortex three site breathers cannot be supported since they are highly unstable

On the stability of multibreathers in Klein-Gordon chains

In the present paper, a theorem, which determines the linear stability of multibreathers in Klein-Gordon chains, is proven. Specifically, it is shown that for soft nonlinearities, and positive inter-site coupling, only structures with adjacent sites excited out-of-phase may be stable, while only in-phase ones may be stable for negative coupling. The situation is reversed for hard nonlinearities. This theorem can be applied in $n$-site breathers, where $n$ is any finite number and provides an $\cal{O}(\sqrt{\epsilon})$ estimation of the characteristic exponents of the solution. To complement the analysis, we perform numerical simulations and establish that the results are in excellent agreement with the theoretical predictions, at least for small values of the coupling constant $\epsilon$

Estimation of the safety of anesthesiological protection in operative delivery

The comparative analysis of influence of various methods of anesthesiological aid on some parameters of mothers' hemodynamics and condition of an intra-uterine fetust was performed. 58 pregnant women with physiologically proceeding pregnancy, undergone operative delivery under the conditions of various methods of anesthesia were examined. It was revealed that anesthesia by nitric oxide rendered negative influence on the fetus and was accompanied by lower Apgar score and more expressed level of metabolic acidosis. Application of the general anesthesia medical with xenone and to spinal anesthesia did not render negative influence on the fetus and newborn that allows to recommend both anaesthetic techniques as safe.Проведен сравнительный анализ влияния различных методов анестезиологического пособия на некоторые показатели гемодинамики матери и состояние внутриутробного плода. Исследованы 58 беременных женщин с физиологически протекающей беременностью, подвергшиеся родоразрешению путем кесарева сечения в условиях различных методов анестезии. Выявлено, что анестезия закисью азота оказывала негативное влияние на плод, сопровождалась более низкой оценкой по шкале Апгар и более выраженным уровнем метаболического ацидоза. Применение общей анестезии медицинским ксеноном и спинномозговой анестезии не оказывало отрицательного влияния на плод и новорожденного, что позволяет рекомендовать обе анестезиологические техники, как безопасные