Stationary States in Bistable System Driven by L\'evy Noise

We study the properties of the probability density function (PDF) of a bistable system driven by heavy tailed white symmetric L\'evy noise. The shape of the stationary PDF is found analytically for the particular case of the L\'evy index \alpha = 1 (Cauchy noise). For an arbitrary L\'evy index we employ numerical methods based on the solution of the stochastic Langevin equation and space fractional kinetic equation. In contrast with the bistable system driven by Gaussian noise, in the L\'evy case the positions of maxima of the stationary PDF do not coincide with the positions of minima of the bistable potential. We provide a detailed study of the distance between the maxima and the minima as a function of the potential's depth and L\'evy noise parameters.Comment: Accepted to EPJS

A direction finding technique for the ULF electromagnetic source

International audienceA technique of direction finding is proposed, which can be applied to the magnetic-dipole type source located in the conductive ground. To distinguish a weak ULF source signal from the natural noise a network of multicomponent magnetometers is supposed to be used. The data obtained by the ground-based stations is processed in such a way that a set of partial derivatives of the magnetic perturbations due to the source are found. Comparing these derivatives with theoretical formulae makes it possible, in principle, to find the ULF source parameters such as the distance and amplitude. Averaging the data and a special procedure are proposed in order to exclude random fluctuations in the magnetic moment orientation and to avoid hydrogeological and other local factors

Rook placements in G2G_2 and F4F_4 and associated coadjoint orbits

Let $\mathfrak{n}$ be a maximal nilpotent subalgebra of a simple complex Lie algebra with root system $\Phi$. A subset $D$ of the set $\Phi^+$ of positive roots is called a rook placement if it consists of roots with pairwise non-positive scalar products. To each rook placement $D$ and each map $\xi$ from $D$ to the set $\mathbb{C}^{\times}$ of nonzero complex numbers one can naturally assign the coadjoint orbit $\Omega_{D,\xi}$ in the dual space $\mathfrak{n}^*$. By definition, $\Omega_{D,\xi}$ is the orbit of $f_{D,\xi}$, where $f_{D,\xi}$ is the sum of root covectors $e_{\alpha}^*$ multiplied by $\xi(\alpha)$, $\alpha\in D$. (In fact, almost all coadjoint orbits studied at the moment have such a form for certain $D$ and $\xi$.) It follows from the results of Andr\`e that if $\xi_1$ and $\xi_2$ are distinct maps from $D$ to $\mathbb{C}^{\times}$ then $\Omega_{D,\xi_1}$ and $\Omega_{D,\xi_2}$ do not coincide for classical root systems $\Phi$. We prove that this is true if $\Phi$ is of type $G_2$, or if $\Phi$ is of type $F_4$ and $D$ is orthogonal.Comment: 16 pages, 4 figure

THE CHANGING OF STRUCTURE OF VISUALITY: TRANSFORMATION OF IMAGE’S ROLES IN SOCIAL MEDIA

В статье рассмотрены изменения структуры визуального в контексте ограничения доступа к социальным сетям на территории России в марте 2022 г. Блокировка на неопределенный срок сервисов Twitter, Tiktok, Facebook (признан экстремистской организацией в России) и Instagram (признан экстремистской организацией в России) позволяет спрогнозировать ряд культурных и ценностных изменений для миллионов пользователей.This presentation is devoted to changing of structure of visuality in the context of banning social media in Russia in march 2022. According to author idea, temporary banning services such a Twitter, Tiktok, Facebook(recognized as extremist organization in Russia) and Instagram(recognized as extremist organization in Russia) allow to predict some changing in cultural and values area for millions users

Management of patent ductus arteriosus in premature infants.

Closure of hemodynamically significant patent ductus arterios (HSPDA)  is one of the most important questions in modern neonatal intensive care, especially for preterm babies. Long-term functioning of the hemodynamically significant  arterial duct leads to a large number of complications in premature babies, such as: bronchopulmonary dysplasia, periventricular leucomalacia, intraventricular hemorrhage, retinopathy of the premature. To prevent all these complications, the PDA should be closed pharmacologically or surgically as soon as possible without any hesitation. COX inhibitors are commonly used nowa days. Ibuprofen and indomethacin show the equal efficacy and no significant adverse events. But some patients still need surgical treatment. The aim of the study was to determine the feasibility, effectiveness and safety of using various volumes of infusion in combination with COX inhibitors and to determine its effect on the timing of the closure of PDA. 91 premature infants with a gestational age of 26-31 weeks with manifestations of respiratory distress syndrome and НSPDA were studied retrospectively. Premies were divided into 2 groups. Research groups were representative as to gestational age, gender, and weight (1205.0±435.0 g). Therapy for PDA closure included the use of various volumes of restrictive or liberal infusion therapy (from 50 to 100 ml/kg/day) and COX inhibitors (indomethacin, ibuprofen). The volume of infusion therapy was limited in the first group. Preemies received 53.5±6.4 ml/kg/day on DOL1 and 2. From the third day urine excretion increased and the volume of infusion therapy also raised to 63.6±5.6 ml/kg/day, and on day 5 – to 89.7±6.8 ml/kg/day. In the second group there was no strict limitation of the volume of infusion therapy (especially in the first 5 days). Delayed period of PDA closure (on average from 14.55±0.56 DOL) was associated with absence of limitation of the infusion volume. In the first group, volume of infusion therapy was restricted in the first 5 days, and the closure of the ductus arteriosus occurred extremely early (on 2.35±0.48 DOL). COX inhibitors were prescribed according to the standard scheme: in the first 3 days indomethacin was administered orally in doses of 0.2/0.1/0.1 mg/kg/day. If the premature baby had symptoms of intestinal paresis ( this restricted oral administration of indomethacin), ibuprofen was prescribed in a three-day course in doses of 10/5/5 mg/kg/day intravenously or 20/10/10 mg/kg/day in rectal form. In all  groups, standard PDA closure therapy was used. In the more remote periods (14 and 28 days), there was no fundamental difference in the volume of infusion in all groups. For early PDA closure limitation of infusion therapy in the first 3-5 days in combination with COX is principle

Measurements of the composition of aerosol component of Venusian atmosphere with Vega 1 lander, preliminary data

Preliminary investigation of mass spectra of gaseous products of pyrolyzed Venusian cloud particles collected and analyzed by the complex device of mass-spectrometer and collector pyrolyzer on board Vega 1 lander revealed the presence of heavy particles in the upper cloud layer. Based on 64 amu peak (SO2+), an estimate of the lower limit of the sulfuric acid aerosol content at the 62 to 54 km heights of approximately 2.0 mg/cu m is obtained. A chlorine line (35 and 37 amu) is also present in the mass spectrum with a lower limit of the chlorine concentration of approximately 0.3 mg/ cu m

Perspective of Using Neirowebs as Visual Media

Данный доклад посвящен проблематике использования нейросетей как средства визуальной медиакоммуникации в контексте средств массовой информации. В докладе затрагивается проблема формирования визуальной культуры посредствам генерации изображений по текстовому запросу. В качестве объекта анализа выбраны сервисы Stable Defusion и Midjourney. В качестве исследовательского метода выбран контент-анализ. Критически оценивая потенциал нейронных сетей и искусственного интеллекта в процессе создания визуальности, автор приходит к выводу о необходимости расценивать данный вид изображений как самостоятельное медиа. В рамках доклада приводятся примеры существующих интеграций генеративной графики в традиционные информационные продукты, такие как реклама, новости и искусство.This article is devoted to problems of using of AI as media in the process of media communication. The main goal of this article is to show to problem formation of images from text. Such services as Stable 174 Defusion and Midjourney were chosen for analysis. All data is provided with using content analysis. The potential of AI and neirowebs is estimated critically in the process of creating visuality. According to author, we should evaluate this type of images as independed media. In this article provides examples of existing generative graphics integrations into traditional information products such as advertising, news and art

The nature of the unique precataclysmic variable V664 Cas with two-peaked balmer lines in its spectrum

We analyze photometric and spectroscopic observations of the close binary system V664 Gas. All the characteristics of its radiation are consistent with the star being a cataclysmic variable with powerful reflection effects. The orbital period is refined (P = 0.5816475 d) and the ephemerides of the system determined. The U, B, V, R light curves of V664 Gas display sinusoidal variations with similar amplitudes near Δm = 1.1m. This suggests that a hot spot on the surface of the secondary always dominates the optical radiation of the system. The spectra contain emission lines, two-peaked hydrogen lines, and narrow lines of helium and heavy elements in high ionization states, whose intensities vary synchronously with the brightness. The Hell λ4686 Å line has broad absorption wings that form in the atmosphere of the O subdwarf. The mass function, f(m) = 0.007M⊙, is the lowest among all precataclysmic variables: the mass of the secondary exceeds the mass of the primary by more than a factor of 1.6. A full set of fundamental parameters for V664 Gas is determined based on modeling of the spectra and light curves, taking into account reflection effects in the system. Most of the emission lines are formed under conditions of appreciable deviations from local thermodynamic equilibrium. The possibility of carrying out correct modeling of the Balmer-line profiles assuming the stellar radiation is absorbed in a planetary nebula is demonstrated. © 2004 MAIK "Nauka/ Interperiodica"

Fractographic Study of Fatigue Failure of a High-Pressure Turbine Rotor Blade

The paper presents the results of a factual study of the fracture surface of a high-pressure turbine rotor blade with a fatigue crack. The study of the fracture relief showed that on the fracture surface of the blade near the trailing edge there is a zone of brittle transcrystalline and intergranular fracture, surrounded by an intragranular fracture with a developed microrelief. Further crack growth in the direction of the leading edge was carried out by a fatigue mechanism. As a result, it was found that the main cause of blade failure is the formation and development of a fatigue crack in the direction from the trailing edge of the airfoil to the leading edge. © 2022 American Institute of Physics Inc.. All rights reserved