On the Structure of Advective Accretion Disks At High Luminosity

Global solutions of optically thick advective accretion disks around black holes are constructed. The solutions are obtained by solving numerically a set of ordinary differential equations corresponding to a steady axisymmetric geometrically thin disk. We pay special attention to consistently satisfy the regularity conditions at singular points of the equations. For this reason we analytically expand a solution at the singular point, and use coefficients of the expansion in our iterative numerical procedure. We obtain consistent transonic solutions in a wide range of values of the viscosity parameter alpha and mass acretion rate. We compare two different form of viscosity: one takes the shear stress to be proportional to the pressure, while the other uses the angular velocity gradient-dependent stress. We find that there are two singular points in solutions corresponding to the pressure-proportional shear stress. The inner singular point locates close to the last stable orbit around black hole. This point changes its type from a saddle to node depending on values of alpha and accretion rate. The outer singular point locates at larger radius and is always of a saddle-type. We argue that, contrary to the previous investigations, a nodal-type inner singular point does not introduce multiple solutions. Only one integral curve, which corresponds to the unique global solution, passes simultaneously the inner and outer singular points independently of the type of inner singular point. Solutions with the angular velocity gradient-dependent shear stress have one singular point which is always of a saddle-type and corresponds to the unique global solution. The structure of accretion disks corresponding to both viscosities are similar.Comment: 20 pages, 6 figures, submitted to Ap

Accretion disks around Black Holes with Advection and Optical Depth Transition

We consider the effects of advection and radial gradients of pressure and radial drift velocity on the structure of accretion disks around black holes with proper description of optically thick/thin transitions. We concentrated our efforts on the models with large accretion rate. Contrary to disk models neglecting advection, we find that continuous solutions extending from the outer disk regions to the inner edge exist for all accretion rates we have considered. We show that the sonic point moves outward with increasing accretion rate, and that in the innermost disk region advection acts as a heating process that may even dominate over dissipative heating. Despite the importance of advection on it's structure, the disk remains geometrically thin. Global solutions of advective accretion disks, which describe continuously the transition between optically thick outer region and optically thin inner region are constructed and analyzed.Comment: 13 pages, 8 figures, to be published in Proceedings of the Gamov Memorial International Conference, Odessa, Ukraine, August 8-14, 2004, Cambridge Scientific Publication

Synthesis and antifungal activity of monoterpenoids of the carane series

The antifUngal activity of terpenoids of the carane series was studied; an interaction was found between the structures of these compounds and their antifungal properties. The actions of several terpenoids on the adhesive activity and enzyme systems of the fungus Candida albicans were studied. © 2012 Springer Science+Business Media, Inc

Hemocoagulation Activity of Sulfur-Containing Pinane-Type Terpenoids

© 2017, Springer Science+Business Media, LLC. A series of pinane-type sulfides and sulfoxides were synthesized from (1S)-(–)-β-pinene. Their hemocoagulation activity in vitro on human blood plasma was studied. All tested compounds exhibited antiaggregation and anticoagulation activity. The most water-soluble sulfoxide with a mercaptoacetic acid moiety inhibited spontaneous platelet aggregation and that induced by collagen and arachidonic acid and also reduced the coagulation activity of human blood plasma. The hemocoagulation activity was due to selective inhibition of platelet receptors, decreased yield of thrombocytic microvesicles, and suppression of their activity

NEREL: A Russian Dataset with Nested Named Entities, Relations and Events

In this paper, we present NEREL, a Russian dataset for named entity recognition and relation extraction. NEREL is significantly larger than existing Russian datasets: to date it contains 56K annotated named entities and 39K annotated relations. Its important difference from previous datasets is annotation of nested named entities, as well as relations within nested entities and at the discourse level. NEREL can facilitate development of novel models that can extract relations between nested named entities, as well as relations on both sentence and document levels. NEREL also contains the annotation of events involving named entities and their roles in the events. The NEREL collection is available via https://github.com/nerel-ds/NEREL. © 2021 Incoma Ltd. All rights reserved.The project is supported by the Russian Science Foundation, grant # 20-11-20166. The experiments were partially carried out on computational resources of HPC facilities at HSE University. We are grateful to Alexey Yandutov and Igor Rozhkov for providing results of their experiments in named entity recognition and relation extraction

Vortex studies in superconducting Ba(Fe0.93Co0.07)2As2

We present small-angle neutron scattering (SANS) and Bitter decoration studies of the superconducting vortices in Ba(Fe$_{0.93}$Co$_{0.07}$)$_2$As$_2$}. A highly disordered vortex configuration is observed at all measured fields, and is attributed to strong pinning. This conclusion is supported by the absence of a Meissner rim in decoration images obtained close to the sample edge. The field dependence of the magnitude of the SANS scattering vector indicates vortex lattice domains of (distorted) hexagonal symmetry, consistent with the decoration images which show primarily 6-fold coordinated vortex domains. An analysis of the scattered intensity shows that this decreases much more rapidly than expected from estimates of the upper critical field, consistent with the large degree of disorder.Comment: 5 pages, 4 figure

An Analytical Study on the Multi-critical Behaviour and Related Bifurcation Phenomena for Relativistic Black Hole Accretion

We apply the theory of algebraic polynomials to analytically study the transonic properties of general relativistic hydrodynamic axisymmetric accretion onto non-rotating astrophysical black holes. For such accretion phenomena, the conserved specific energy of the flow, which turns out to be one of the two first integrals of motion in the system studied, can be expressed as a 8$^{th}$ degree polynomial of the critical point of the flow configuration. We then construct the corresponding Sturm's chain algorithm to calculate the number of real roots lying within the astrophysically relevant domain of $\mathbb{R}$. This allows, for the first time in literature, to {\it analytically} find out the maximum number of physically acceptable solution an accretion flow with certain geometric configuration, space-time metric, and equation of state can have, and thus to investigate its multi-critical properties {\it completely analytically}, for accretion flow in which the location of the critical points can not be computed without taking recourse to the numerical scheme. This work can further be generalized to analytically calculate the maximal number of equilibrium points certain autonomous dynamical system can have in general. We also demonstrate how the transition from a mono-critical to multi-critical (or vice versa) flow configuration can be realized through the saddle-centre bifurcation phenomena using certain techniques of the catastrophe theory.Comment: 19 pages, 2 eps figures, to appear in "General Relativity and Gravitation

Modern medical science from the standpoint of students

В статті наведено аналіз результатів анкетування студентів-медиків стосовно їх ставлення до науки, оцінки рівня розвитку науки в Україні, характеристики складових іміджу науки, бачення можливих змін, загальних принципів наукової роботи студентів. Всі респонденти вказали важливість науки для суспільства, та необхідність зміни ставлення до науки в державі на сучасному етапі. Аналіз відповідей показав, що студенти мають чіткі характеристики предметного і соціального іміджу науки та особистісних рис сучасного науковця. Нажаль, престиж професії вченого вони схильні оцінювати як невисокий; The article contains the analysis of medical students survey about their attitudes to science, assessing the level of the science development in Ukraine, the characteristics of the science image components, visions of possible changes, general principles of student’s scientific work. All the respondents indicated the importance of science to society and the need to change the attitudes to science in our country today. Analysis of the responses showed that students had clear characteristics of objective and social science image and personality traits of the modern scientist. Unfortunately, they tend to evaluate the prestige of the scientist as low

Development of Approaches to the Study of the Interaction of Biologically Active Thioterpenoids with Model Membranes

© 2017, Springer Science+Business Media, LLC. It was shown that the synthesized camphene sulfone, in contrast to acetylsalicylic acid and clopidogrel, completely inhibits the activation of platelets induced by adrenaline and arachidonic acid, and reduces the influence of ADP, collagen, and ristocetin. Detailed NMR studies and molecular dynamics simulations using model SDS membranes indicated that the sulfone is embedded by its bicyclic part inside the SDS micelle, whereas -SO 2 (CH 2 ) 2 OH fragment of sulfone is located on the outer part of the micelle and accessible for solvent. It was ascertained that hemocoagulant activity of sulfone is caused by its capability of inhibition of platelet activation and suppression of catalytic activity of phospholipid surface participating in formation of coagulation complexes of clotting factors

Combination of Endobronchial Ultrasound and Modern Cytological Diagnosis in Patients With Intrathoracic Lesions

Objective: To evaluate the effectiveness of endobronchial (EBUS) and endoscopic ultrasound (EUS) in cytomorphological verification of a malignant process using the transbronchial needle aspiration (TBNA) of the lymph nodes and mediastinal organs.Materials and methods: In 2017–2019 we analyzed the cytological samples (standard and cell block) of 172 patients (115 males and 57 females) with an average age of 61 years (25–82 years) in the clinical diagnostic laboratory of Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation). Of them 111 were used for immunocytochemical analysis. The majority of the studies (77) were performed in patients with lung cancer in order to identify the stage of the disease. We used combined bronchoscopy under general anesthesia in the operating room with high-frequency ventilation and a rapid on-site evaluation (ROSE).Results: We found the lymph node and mediastinal invasion in 140 (81%) patients who underwent EBUS-EUS TBNA. The non-diagnostic results were obtained in 32 (19%) patients. The combination of EUS and EBUS with TBNA showed the highest effectiveness in the mentioned clinical cases. The sensitivity, specificity, and accuracy of the cytologic analysis during EBUS and EUS with TBNA and no ROSE were 89%, 100%, and 90%, respectively. ROSE reduced the rate of non-diagnostic results and increased the sensitivity (96%), specificity (100%), and accuracy (97%) of the cytologic evaluation.Conclusions: According to the obtained results, we recommend using EBUS-EUS TBNA modalities for morphological verification of the mediastinal lymph nodes as a routine invasive diagnosis component of the preoperative evaluation in patients with lung cancer