Dynamics of Vortex Pair in Radial Flow

The problem of vortex pair motion in two-dimensional plane radial flow is solved. Under certain conditions for flow parameters, the vortex pair can reverse its motion within a bounded region. The vortex-pair translational velocity decreases or increases after passing through the source/sink region, depending on whether the flow is diverging or converging, respectively. The rotational motion of two corotating vortexes in a quiescent environment transforms into motion along a logarithmic spiral in the presence of radial flow. The problem may have applications in astrophysics and geophysics.Comment: 13 pages, 9 figure

A Dipole Vortex Model of Obscuring Tori in Active Galaxy Nuclei

The torus concept as an essential structural component of active galactic nuclei (AGN) is generally accepted. Here, the situation is discussed when the torus "twisting" by the radiation or wind transforms it into a dipole toroidal vortex which in turn can be a source of matter replenishing the accretion disk. Thus emerging instability which can be responsible for quasar radiation flares accompanied by matter outbursts is also discussed. The "Matreshka" scheme for an obscuring vortex torus structure capable of explaining the AGN variability and evolution is proposed. The model parameters estimated numerically for the luminosity close to the Eddington limit agree well with the observations.Comment: 17 pages, 11 figures, version of this paper is published in Astronomy Report

Gravitational potential of a homogeneous circular torus: new approach

The integral expression for gravitational potential of a homogeneous circular torus composed of infinitely thin rings is obtained. Approximate expressions for torus potential in the outer and inner regions are found. In the outer region a torus potential is shown to be approximately equal to that of an infinitely thin ring of the same mass; it is valid up to the surface of the torus. It is shown in a first approximation, that the inner potential of the torus (inside a torus body) is a quadratic function of coordinates. The method of sewing together the inner and outer potentials is proposed. This method provided a continuous approximate solution for the potential and its derivatives, working throughout the region.Comment: 10 pages, 9 figures, 1 table; some misprints in formulae were correcte

KiDS-SQuaD: The KiDS Strongly lensed Quasar Detection project

New methods have been recently developed to search for strong gravitational lenses, in particular lensed quasars, in wide-field imaging surveys. Here, we compare the performance of three different, morphology- and photometry- based methods to find lens candidates over the Kilo-Degree Survey (KiDS) DR3 footprint (440 deg$^2$). The three methods are: i) a multiplet detection in KiDS-DR3 and/or Gaia-DR1, ii) direct modeling of KiDS cutouts and iii) positional offsets between different surveys (KiDS-vs-Gaia, Gaia-vs-2MASS), with purpose-built astrometric recalibrations. The first benchmark for the methods has been set by the recovery of known lenses. We are able to recover seven out of ten known lenses and pairs of quasars observed in the KiDS DR3 footprint, or eight out of ten with improved selection criteria and looser colour pre-selection. This success rate reflects the combination of all methods together, which, taken individually, performed significantly worse (four lenses each). One movelty of our analysis is that the comparison of the performances of the different methods has revealed the pros and cons of the approaches and, most of all, the complementarities. We finally provide a list of high-grade candidates found by one or more methods, awaiting spectroscopic follow-up for confirmation. Of these, KiDS 1042+0023 is to our knowledge the first confirmed lensed quasar from KiDS, exhibiting two quasar spectra at the same source redshift at either sides of a red galaxy, with uniform flux-ratio $f\approx1.25$ over the wavelength range $0.45\mu\mathrm{m}<\lambda<0.75\mu\mathrm{m}.$Comment: 12 pages, 4 figures, 4 tables, accepted for publication in MNRA

Dynamical model of an obscuring clumpy torus in AGNs - I. Velocity and velocity dispersion maps for interpretation of ALMA observations

We have developed the dynamical model of a clumpy torus in an active galactic nucleus (AGN) and compared to recent The Atacama Large Millimeter Array (ALMA) observations. We present N-body simulations of a torus in the field of a supermassive black hole (SMBH), made of up to N = 105 gravitationally interacting clouds. As initial conditions, we choose random distributions of the orbital elements of the clouds with a cut-off in the inclination to mimic the presence of wind cones produced at the early AGN stage. When the torus reaches an equilibrium, it has a doughnut shape. We discuss the presence of box orbits. We have then constructed the velocity and velocity dispersion maps using the resulting distributions of the clouds at equilibrium. The effects of torus inclination and cloud sizes are duly analysed. We discuss the obscuration effects of the clouds using a ray tracing simulation matching the model maps to ALMA resolution. By comparing the model with the observational maps of NGC 1068, we find that the SMBH mass is M_\\text{smbh}=5\\times 10^6 \\, \\mathrm{M}_\\odot for the range of the torus inclination angles 45°-60°. We also construct the velocity dispersion maps for NGC 1326 and NGC 1672. They show that the peaks in the ALMA dispersion maps are related to the emission of the torus throat. Finally, we obtain the temperature distribution maps with parameters that correspond to our model velocity maps for NGC 1068. They show stratification in temperature distribution with the shape of the high-temperature region as in the VLTI/MIDI map

Microstructure and magnetoresistance of Co90Fe10/Cu and Co65Fe26Ni9/Cu multilayers

Investigations of the microstructure, magnetic and magnetotransport properties of the optimized [Co90Fe10/Cu]n and [Co65Fe26Ni9/Cu] n multilayers with n = 32 prepared by magnetron sputtering are performed. These nanostructures exhibit the magnetoresistance values 83 % and 36 % at room temperature, respectively. The article presents the results of the influence of Co65Fe26Ni9 alloy on the magnetoresistance values and crystal structure of multilayers. In the periodic part of the nanostructure [Co65Fe26Ni9/Cu] n based on CoFeNi ternary alloy, besides fcc the formation of a bcc phase in the continuous boundaries around crystallites is found. © Published under licence by IOP Publishing Ltd

Декларативна оцінка ефективності засобів блокування трекерів збору інформації з комп’ютерної системи при користуванні вебресурсами

Носов, В. В. Декларативна оцінка ефективності засобів блокування трекерів збору інформації з комп’ютерної системи при користуванні вебресурсами / Носов Віталій Вікторович, Баннікова Марія Андріївна // Застосування інформаційних технологій у правоохоронній діяльності: матеріали Круглого столу (м. Харків, 14 груд. 2022 р.) / МВС України, Харк. нац. ун-т внутр. справ, Ф-т № 6, Каф. кібербезпеки та DATA-технологій. – Харків: ХНУВС, 2022. – С. 62-65.Проведено декларативну оцінку ефективності засобів блокування трекерів і спеціальних запитів для браузерів Mozilla Firefox та Google Chrome.A declarative evaluation of the effectiveness of tracker blocking tools and special requests for Mozilla Firefox and Google Chrome browsers was carried out.Проведена декларативная оценка эффективности средств блокировки трекеров и специальных запросов для браузеров Mozilla Firefox и Google Chrome

Продолжительность жизни у работников ПО «Маяк» после острой лучевой болезни разной степени тяжести

Assessment of the impact of radiation exposure on human lifetime is an actual problem in radiation medicine. The aim of the study was to assess lifetime in Mayak PA workers who had developed acute radiation syndrome following accidental acute high-dose external exposure and in those individuals who had taken part in nuclear accidents but had not developed the syndrome. Study analyses considered 58 deceased Mayak PA workers (50 males and 8 females) and were performed using STATISTICA 10 software. Five indicators of lifetime were studied: static – before and after acute exposure, total lifetime, as well as potential – potential years of life lost and the proportion of people who lived less than 35 years. The study demonstrated significant decrease in static indicators excluding lifetime before acute exposure and increase in potential indicators of lifetime in workers with severe and especially with extreme acute radiation syndrome compared to workers with moderate and modest acute radiation syndrome and to workers free of the syndrome. The reason for the decrease of lifetime in workers with extreme acute radiation syndrome was extremely severe course of the disease. Decrease of lifetime in cases with severe level of the syndrome was mainly due to early death from malignancies. A significant linear regression association with natural logarithm of acute radiation dose in Gy was observed for lifetime indicators. At 1 logarithm of the radiation dose, the lifetime after acute exposure was reduced by 8.3 years, total lifetime by 8.8 years, and potential years of life lost increased by 8.4 years. The relative risk of the increase of the proportion of workers with less than 35 years of life was considerably higher in workers with extreme and severe acute radiation syndrome and in workers with acute radiation doses above 10 Gy compared to other groups of workers: 26.8 and 18.8 (95% CI: 3.8–191.1 and 2.7–129.8; p&lt;0.001), respectively. Thus, for the first time, a reduction in lifetime after acute radiation syndrome was found among Mayak PA workers.Оценка влияния радиационного воздействия на продолжительность жизни человека – актуальная проблема радиационной медицины. Целью исследования явился анализ продолжительности жизни в группе работников ПО «Маяк» после острой лучевой болезни, подвергшихся в результате аварийных ситуаций острому внешнему облучению в значительных дозах, и участников аварий без заболевания. Анализ проведен у 58 умерших работников ПО «Маяк» (50 мужчин и 8 женщин) с помощью программы STATISTICA 10. Изучены 5 показателей продолжительности жизни: статичные – до и после острого облучения, общая продолжительность жизни, а также потенциальные – потерянные годы потенциальной жизни и доля лиц, проживших менее 35 лет. В результате исследования у работников с тяжелой и особенно крайне тяжелой степенью болезни относительно работников средней и легкой степени тяжести заболевания и участников аварий установлено статистически значимое сокращение статичных показателей, за исключением продолжительности жизни до острого облучения, и повышение потенциальных показателей. Причиной сокращения продолжительности жизни при крайне тяжелой степени заболевания было его экстремальное течение. При тяжелой степени тяжести сокращение продолжительности жизни было обусловлено, главным образом, преждевременной смертностью от злокачественных новообразований. Установлена статистически значимая линейная регрессионная зависимость показателей продолжительности жизни от натурального логарифма дозы острого облучения. На 1 логарифм дозы облучения продолжительность жизни после острого облучения сокращалась на 8,3 лет, общая – на 8,8 лет, а потерянные годы потенциальной жизни повышались на 8,4 лет. Относительный риск повышения доли работников, проживших менее 35 лет при заболевании тяжелой и крайне тяжелой степени тяжести, а также при дозах острого облучения более 10 Гр по сравнению с остальными работниками, был существенно повышен, составив 26,8 и 18,8 (ДИ: 3,8–191,1 и 2,7–129,8; p &lt;0,001) соответственно. Таким образом, у работников ПО «Маяк» впервые установлено сокращение продолжительности жизни после острой лучевой болезни