230 research outputs found

    TECHNIKI ROZPOZNAWANIA TWARZY

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    The problem of face recognition is discussed. The main methods of recognition are considered. The calibrated stereo pair for the face and calculating the depth map by the correlation algorithm are used. As a result, a 3D mask of the face is obtained. Using three anthropomorphic points, then constructed a coordinate system that ensures a possibility of superposition of the tested mask.Omawiany jest problem rozpoznawania twarzy. Rozważane są główne metody rozpoznawania. Użyta zostaje skalibrowana para stereo dla twarzy oraz obliczanie mapy głębokości poprzez algorytm korelacji. W wyniku takiego, uzyskiwana jest maska twarzy w wymiarze 3D. Użycie trzech antropomorficznych punktów, a następnie skonstruowany systemu współrzędnych zapewnia możliwość nakładania się przetestowanej maski

    Properties of polydisperse tin-doped dysprosium and indium oxides

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    The results of investigations of the complex permittivity, diffuse-reflectance, and characteristics of crystal lattices of tin-doped indium and dysprosium oxides are presented. Using the methods of spectroscopy and X-ray diffraction analysis, it is shown that doping of indium oxide with tin results in a significant increase of the components of the indium oxide complex permittivity and an appearance of the plasma resonance in its diffuse-reflectance spectra. This indicates the appearance of charge carriers with the concentration of more than 1021 cm−3 in the materials. On the other hand, doping of the dysprosium oxide with the same amount of tin has no effect on its optical and electromagnetic properties

    Twisted Nanotubes of Transition Metal Dichalcogenides with Split Optical Modes for Tunable Radiated Light Resonators

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    Synthesized micro- and nanotubes composed of transition metal dichalcogenides (TMDCs) such as MoS2_2 are promising for many applications in nanophotonics, because they combine the abilities to emit strong exciton luminescence and to act as whispering gallery microcavities even at room temperature. In addition to tubes in the form of hollow cylinders, there is an insufficiently-studied class of twisted tubes, the flattened cross section of which rotates along the tube axis. As shown by theoretical analysis, in such nanotubes the interaction of electromagnetic waves excited at opposite sides of the cross section can cause splitting of the whispering gallery modes. By studying micro-photoluminescence spectra measured along individual MoS2_2 tubes, it has been established that the splitting value, which controls the energies of the split modes, depends exponentially on the aspect ratio of the cross section, which varies in "breathing" tubes, while the relative intensity of the modes in a pair is determined by the angle of rotation of the cross section. These results open up the possibility of creating multifunctional tubular TMDC nanodevices that provide resonant amplification of self-emitting light at adjustable frequencies

    Treatment of toxic hepatitis in COVID-19 patients

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    Background. The article reflects the clinical significance of the early diagnosis of toxic hepatitis in patients who have undergone a new coronavirus infection with the determination of clinical and laboratory predictors of the response to therapy. A dynamic analysis of the effectiveness of toxic hepatitis therapy in patients of three experimental groups and a control group is presented. Aim. The aim of the present study is to increase the effectiveness of the treatment of toxic hepatitis in patients who have undergone COVID-19. Materials and methods. On the basis of the newly created infection centers of the Central Clinical Hospital RZhD-Medicine and Vishnevsky 3-rd Central Military Clinical Hospital 996 patients with COVID-19, who had clinical and laboratory signs of toxic liver damage (cytolytic and/or cholestatic syndromes) against the background of COVID-19 therapy. Results. On the 14th day from the start of therapy in group 3, there was a significant decrease in the clinical manifestations of jaundice in 163 (72.8%) patients, on the 21st day of treatment, this symptom was stopped in all patients. In groups 1 and 2, the decrease in clinical manifestations of jaundice was significantly lower 122 (55.2%) and 134 (58.8%); p0.05. At the end of therapy, no manifestations of jaundice were observed in all experimental groups, while in the control group, symptom reduction was achieved only in 47 (14.5%) patients. Conclusion. The use of drugs with hepatoprotective effect in the form of monotherapy in groups 1 (UDCA) and 2 (ademethionine) showed a low therapeutic effect with positive dynamics of clinical and laboratory indicators of toxic hepatitis activity. The use of combined treatment in group 3 (UDCA and ademethionine) demonstrated the maximum therapeutic effect, pronounced positive dynamics in the form of normalization of clinical and laboratory indicators of toxic hepatitis activity

    КЛИНИЧЕСКИЙ СЛУЧАЙ ЭНДОВАСКУЛЯРНОГО ЛЕЧЕНИЯ ПОСТТРАВМАТИЧЕСКОЙ АНЕВРИЗМЫ ПОЧЕЧНОЙ АРТЕРИИ

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    Introduction. Aneurysm of renal artery is a rare and complex pathology of renal bloodstream. Large percentage of observations show that renal artery aneurysms are iatrogenic and happen due to urological interventions. Traumatic aneurysms are much less frequent. By the nature of the blood supply arterial aneurysms are subdiveded into those, which occur when the injured organ is only artery and arteriovenous aneurysms that occur while an artery is damaged along with the accompanying veins. Aneurysms may be treated only surgically, and the only exception is pregnancy. It is possible to use the open treatment option such as aneurysm resection with prosthetics, reanastomosing or its collateral plastics of the renal artery; exclusion of aneurysm with shunting of renal artery or its branches; resection of aneurysm with anastomosing of artery with azygos splanchnic arteries; complex reconstruction using autovein or internal iliac artery segment; including kidney resection at local infarction or nephrectomy in the case of evident nephrosclerosis.Materials and methods. This paper presents a clinical case of successful minimally invasive surgical treatment of traumatic aneurysm of renal artery. It was carried out through stenting of the right lowpolar renal artery: a coronary sheath was used to transfuse and implant the Explorer-Itgimedical Aneugraft 3.0 * 18.0 mm graft-system; the stent-graft was implanted into the right lowpolar renal artery so that it covers the aneurysm ostium. Results. The above case shows the possibility to successfully apply the endovascular method to treat posttraumatic aneurysms of renal arteries with derivative circulation.Conclusion. This technique can be safely and successfully used as an alternative to the traditional «open» surgery, as it is minimally invasive, and allows performing a complete blockade of the pathological blood flow and to avoid an additional operating trauma and compromenation of distal branches. Введение. Аневризма почечных артерий – редкая и сложная патология сосудистого русла почки. В большом проценте наблюдений аневризмы почечных артерий являются ятрогенными, возникающими в результате интервенционных урологических вмешательств. Травматические аневризмы встречаются значительно реже. По характеру кровоснабжения различают артериальные аневризмы, возникающие при ранении только артерии, и артериовенозные аневризмы, возникающие при одновременном повреждении артерии и сопутствующей вены. Лечение аневризм возможно только хирургическим способом, исключением является только беременность. Возможно применение открытых методов лечения, таких как резекция аневризмы с протезированием, реанастомозированием или ее боковой пластикой почечной артерии; выключение аневризмы с шунтированием почечной артерии или ее ветвей; резекция аневризмы с анастомозированием артерии с непарными висцеральными артериями; сложные реконструкции с использованием аутовены или сегмента внутренней подвздошной артерии; в том числе применение резекции почки при локальном инфаркте или нефрэктомии в случае выраженного нефросклероза. Материалы и методы. В данной работе представлен клинический случай успешного малоинвазивного хирургического лечения травматической аневризмы почечной артерии. Для этого выполнено стентирование правой нижнеполюсной почечной артерии: по коронарному проводнику проведена и имплантирована графт-система Itgimedical Aneugraft 3,0*18,0 мм – стент-графт имплантирован в нижнеполюсную правую почечную артерию с перекрытием шейки аневризмы.Результаты. Приведенный случай показывает возможность успешного применения эндоваскулярного метода для лечения посттравматических аневризм почечных артерий с артериовенозным сбросом.Заключение. Данная методика может безопасно и с успехом применяться в качестве альтернативы традиционного «открытого» хирургического вмешательства, поскольку она малоинвазивна, позволяет выполнять полную блокаду патологического кровотока, избегать дополнительной операционной травмы и компрометации дистальных ветвей.

    Polarized blazar X-rays imply particle acceleration in shocks

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    Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to around 1 TeV. Although the jets are known to be ultimately powered by a supermassive black hole, how the particles are accelerated to such high energies has been an unanswered question. The process must be related to the magnetic field, which can be probed by observations of the polarization of light from the jets. Measurements of the radio to optical polarization—the only range available until now—probe extended regions of the jet containing particles that left the acceleration site days to years earlier1,2,3, and hence do not directly explore the acceleration mechanism, as could X-ray measurements. Here we report the detection of X-ray polarization from the blazar Markarian 501 (Mrk 501). We measure an X-ray linear polarization degree ΠX of around 10%, which is a factor of around 2 higher than the value at optical wavelengths, with a polarization angle parallel to the radio jet. This points to a shock front as the source of particle acceleration and also implies that the plasma becomes increasingly turbulent with distance from the shock

    Discovery of X-ray polarization angle rotation in active galaxy Mrk 421

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    The magnetic field conditions in astrophysical relativistic jets can be probed by multiwavelength polarimetry, which has been recently extended to X-rays. For example, one can track how the magnetic field changes in the flow of the radiating particles by observing rotations of the electric vector position angle Ψ\Psi. Here we report the discovery of a Ψx\Psi_{\mathrm x} rotation in the X-ray band in the blazar Mrk 421 at an average flux state. Across the 5 days of Imaging X-ray Polarimetry Explorer (IXPE) observations of 4-6 and 7-9 June 2022, Ψx\Psi_{\mathrm x} rotated in total by 360\geq360^\circ. Over the two respective date ranges, we find constant, within uncertainties, rotation rates (80±980 \pm 9 and 91±8/day91 \pm 8 ^\circ/\rm day) and polarization degrees (Πx=10%±1%\Pi_{\mathrm x}=10\%\pm1\%). Simulations of a random walk of the polarization vector indicate that it is unlikely that such rotation(s) are produced by a stochastic process. The X-ray emitting site does not completely overlap the radio/infrared/optical emission sites, as no similar rotation of Ψ\Psi was observed in quasi-simultaneous data at longer wavelengths. We propose that the observed rotation was caused by a helical magnetic structure in the jet, illuminated in the X-rays by a localized shock propagating along this helix. The optically emitting region likely lies in a sheath surrounding an inner spine where the X-ray radiation is released

    X-ray Polarization Observations of BL Lacertae

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    Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus the Synchrotron emission to be responsible for the low frequency peak, while the origin of the high frequency hump is still debated. The analysis of X-rays and their polarization can provide a valuable tool to understand the physical mechanisms responsible for the origin of high-energy emission of blazars. We report the first observations of BL Lacertae performed with the Imaging X-ray Polarimetry Explorer ({IXPE}), from which an upper limit to the polarization degree ΠX<\Pi_X<12.6\% was found in the 2-8 keV band. We contemporaneously measured the polarization in radio, infrared, and optical wavelengths. Our multiwavelength polarization analysis disfavors a significant contribution of proton synchrotron radiation to the X-ray emission at these epochs. Instead, it supports a leptonic origin for the X-ray emission in BL Lac.Comment: 17 pages, 5 figures, accepted for publication in ApJ

    Alignment of the CMS silicon tracker during commissioning with cosmic rays

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    This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe CMS silicon tracker, consisting of 1440 silicon pixel and 15 148 silicon strip detector modules, has been aligned using more than three million cosmic ray charged particles, with additional information from optical surveys. The positions of the modules were determined with respect to cosmic ray trajectories to an average precision of 3–4 microns RMS in the barrel and 3–14 microns RMS in the endcap in the most sensitive coordinate. The results have been validated by several studies, including laser beam cross-checks, track fit self-consistency, track residuals in overlapping module regions, and track parameter resolution, and are compared with predictions obtained from simulation. Correlated systematic effects have been investigated. The track parameter resolutions obtained with this alignment are close to the design performance.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
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