Three-dimensional localized coherent structures of surface turbulence. III Experiment and model validation

The paper continues a series of publications devoted to the 3D nonlinear localized coherent structures on the surface of vertically falling liquid films. The work is primarily focussed on experimental investigations. We study: (i) instabilities and transitions leading to 3D coherent structures; (ii) characteristics of these structures. Some nonstationary effects are also studied numerically. Our experimental results, as well as the results of other investigators, are in a good agreement with our theoretical and numerical predictions.Comment: 42 pages, 15 figure

Unusual formations of the free electromagnetic field in vacuum

It is shown that there are exact solutions of the free Maxwell equations (FME) in vacuum allowing an existence of stable spherical formations of the free magnetic field and ring-like formations of the free electric field. It is detected that a form of these spheres and rings does not change with time in vacuum. It is shown that these convergent solutions are the result of an interference of some divergent solutions of FME. One can surmise that these electromagnetic formations correspond to Kapitsa's hypothesis about interference origin and a structure of fireball.Comment: Revtex-file, without figures. To get lournal-pdf-copy with figures contact with [email protected]

Coherence lifetimes of excitations in an atomic condensate due to the thin spectrum

We study the quantum coherence properties of a finite sized atomic condensate using a toy-model and the thin spectrum model formalism. The decoherence time for a condensate in the ground state, nominally taken as a variational symmetry breaking state, is investigated for both zero and finite temperatures. We also consider the lifetimes for Bogoliubov quasi-particle excitations, and contrast them to the observability window determined by the ground state coherence time. The lifetimes are shown to exhibit a general characteristic dependence on the temperature, determined by the thin spectrum accompanying the spontaneous symmetry breaking ground state

Stochastic stabilization of cosmological photons

The stability of photon trajectories in models of the Universe that have constant spatial curvature is determined by the sign of the curvature: they are exponentially unstable if the curvature is negative and stable if it is positive or zero. We demonstrate that random fluctuations in the curvature provide an additional stabilizing mechanism. This mechanism is analogous to the one responsible for stabilizing the stochastic Kapitsa pendulum. When the mean curvature is negative it is capable of stabilizing the photon trajectories; when the mean curvature is zero or positive it determines the characteristic frequency with which neighbouring trajectories oscillate about each other. In constant negative curvature models of the Universe that have compact topology, exponential instability implies chaos (e.g. mixing) in the photon dynamics. We discuss some consequences of stochastic stabilization in this context.Comment: 4 pages, 3 postscript figures in color which are also appropriate for black and white printers; v2 emphasizes relevance to flat as well as negatively curved cosmologies; to appear in J. Phys.

Dipolar superfluidity in electron-hole bilayer systems

Bilayer electron-hole systems, where the electrons and holes are created via doping and confined to separate layers, undergo excitonic condensation when the distance between the layers is smaller than typical distance between particles within a layer. We argue that the excitonic condensate is a novel dipolar superfluid in which the phase of the condensate couples to the {\it gradient} of the vector potential. We predict the existence of dipolar supercurrent which can be tuned by an in-plane magnetic field and detected by independent contacts to the layers. Thus the dipolar superfluid offers an example of excitonic condensate in which the {\it composite} nature of its constituent excitons is manifest in the macroscopic superfluid state. We also discuss various properties of this superfluid including the role of vortices.Comment: 5 pages, 1 figure, minor changes and added few references; final published versio

Влияние мексидола на физическую и умственную работоспособность при стрессогенных воздействиях в эксперименте

The effect of Mexidol on physical performance of mice under the extreme conditions of the weight-loaded forced swim test and on the mental performance of rats under the conditions of a neurosis-like state caused by a functional disturbance of a defensive instrumental conditioned active avoidance reflex was studied. A single dose (50 and 100 mg/kg) or a subchronic regimen (100 mg/kg) of Mexidol administered intrapertoneally enhances the physical performance of mice similarly to mildronate (100 mg/kg). Mexidol improves the rate of operant conditioning, the preservation of the memory trace and its restoration after single or multiple instances of disruption of the conditioned active avoidance reflex, and its effect does not differ from the effect of the comparison drug piracetam (300 mg/kg).Изучено влияния мексидола на физическую работоспособность мышей в экстремальных условиях теста «Плавание с грузом» и на умственную работоспособность крыс в условиях неврозоподобного состояния, вызванного функциональным нарушением сформированного инструментального оборонительного рефлекса активного избегания. Показана способность мексидола как при однократном (50 и 100 мг/кг), так и при субхроническом внутрибрюшинном введении (100 мг/кг) увеличивать физическую работоспособность мышей, сопоставимую по эффективности с милдронатом (100 мг/кг). Установлена способность мексидола улучшать скорость формирования условных реакций, сохранение памятного следа и его восстановление при однократных и повторных функциональных нарушениях условного рефлекса активного избегания, не отличающаяся по эффективности действия от препарата сравнения пирацетама (300 мг/кг)

Short-Wave Excitations in Non-Local Gross-Pitaevskii Model

It is shown, that a non-local form of the Gross-Pitaevskii equation allows to describe not only the long-wave excitations, but also the short-wave ones in the systems with Bose-condensate. At given parameter values, the excitation spectrum mimics the Landau spectrum of quasi-particle excitations in superfluid Helium with roton minimum. The excitation wavelength, at which the roton minimum exists, is close to the inter-particle interaction range. It is shown, that the existence domain of the spectrum with a roton minimum is reduced, if one accounts for an inter-particle attraction.Comment: 5 pages, 5 figures, UJP style; presented at Bogolyubov Kyiv Conference "Modern Problems of Theoretical and Mathematical Physics", September 15-18, 200

A Modelling System for Dead Wood Assessment in the Forests of Northern Eurasia

Dead wood, including coarse woody debris, CWD, and fine woody debris, FWD, plays a substantial role in forest ecosystem functioning. However, the amount and dynamics of dead wood in the forests of Northern Eurasia are poorly understood. The aim of this study was to develop a spatially distributed modelling system (limited to the territories of the former Soviet Union) to assess the amount and structure of dead wood by its components (including snags, logs, stumps, and the dry branches of living trees) based on the most comprehensive database of field measurements to date. The system is intended to be used to assess the dead wood volume and the amount of dead wood in carbon units as part of the carbon budget calculation of forests at different scales. It is presented using multi-dimensional regression equations of dead wood expansion factors (DWEF)—the ratio of the dead wood component volume to the growing stock volume of the stands. The system can be also used for the accounting of dead wood stock and its dynamics in national greenhouse gas inventories and UNFCCC reporting. The system’s accuracy is satisfactory for the average level of disturbance regimes but it may require corrections for regions with accelerated disturbance regimes

Влияние трифтазина на проявления расстройств аутистического спектра у крыс с фетальным вальпроатным синдромом

The effect of triftazin (trifluoperazine) on social interaction abnormalities as a main feature of autism spectrum disorders, exploratory behavior and learning capacity was studied in rats with fetal valproatate syndrome. It was shown that triftazin at a dose of 0,35 mg/kg does not affect the deficit of social interaction, spatial learning or memory but improves exploratory activity by decreasing anxiety in rats with fetal valproate syndrome.На модели фетального вальпроатного синдрома у крыс изучено влияние трифтазина на нарушение социального взаимодействия как основного показателя расстройства аутистического спектра, а также на ориентировочно-исследовательское поведение и способность к обучению животных. Показано, что трифтазин в дозе 0,35 мг/кг не влияет на дефицит социального взаимодействия и показатели пространственного обучения и памяти, но улучшает ориентировочно-исследовательскую активность за счёт снижения тревожности у крыс с фетальным вальпроатным синдромом

Изучение противопаркинсонического, противовоспалительного и анальгетического действия метаболита гимантана АДК-1058 в сравнении с гимантаном

Antiparkinsonian, anti-inflammatory and analgesic activity of ADK-1058, a metabolite of hemantane, was investigated in comparison with hemantane at the effective dose of 20 mg/kg. ADK-1058 exhibits a minor antiparkinsonian effect by reducing the severity of oLigokinesia in C57BL/6 mice with MPTP-induced parkinsonian syndrome. ADK-1058 exhibits anti-inflammatory activity in the model of acetic acid peritonitis, but has no analgesic effect in visceral or somatic pain in mice. Effects of ADK-1058 at the dose of 20 mg/kg do not exceed antiparkinsonian, anti-inflammatory or analgesic effects of hemantane at the dose of 20 mg/kg.В сравнительном аспекте проведено изучение противопаркинсонического, противовоспалительного и противоболевого действия метаболита гимантана АДК-1058 и гимантана в эффективной дозе 20 мг/кг. АДК-1058 проявляет слабую противопаркинсоническую активность, снижая выраженность олигокинезии у мышей С57B1/6 с МФТП-вызванным паркинсоническим синдромом. АДК-1058 проявляет противовоспалительную активность на модели уксуснокислого перитонита, но не оказывает анальгетического действия в отношении висцеральной и соматической боли. Метаболит гимантана АДК-1058 (20 мг/кг) по противопаркинсоническому, противовоспалительному и противоболевому действию не превосходит соответствующую активность гимантана (20 мг/кг)