86 research outputs found

    Electron-positron pairs in hot plasma of accretion column in bright X-ray pulsars

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    The luminosity of X-ray pulsars powered by accretion onto magnetized neutron stars covers a wide range over a few orders of magnitude. The brightest X-ray pulsars recently discovered as pulsating ultraluminous X-ray sources reach accretion luminosity above 1040ergs110^{40}\,{\rm erg\,s^{-1}} which exceeds the Eddington value more than by a factor of ten. Most of the energy is released within small regions in the vicinity of magnetic poles of accreting neutron star - in accretion columns. Because of the extreme energy release within a small volume accretion columns of bright X-ray pulsars are ones of the hottest places in the Universe, where the internal temperature can exceed 100 keV. Under these conditions, the processes of creation and annihilation of electron-positron pairs can be influential but have been largely neglected in theoretical models of accretion columns. In this letter, we investigate properties of a gas of electron-positron pairs under physical conditions typical for accretion columns. We argue that the process of pairs creation can crucially influence both the dynamics of the accretion process and internal structure of accretion column limiting its internal temperature, dropping the local Eddington flux and increasing the gas pressure.Comment: 5 pages, 5 figures, accepted for publication in MNRAS Letter

    On the Possible Enhancement of the Magnetic Field by Neutrino Reemission Processes in the Mantle of a Supernova

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    URCA neutrino reemission processes under the conditions in the mantle of a supernova with a strong toroidal magnetic field are investigated. It is shown that parity violation in these processes can be manifested macroscopically as a torque that rapidly spins up the region of the mantle occupied by such a field. Neutrino spin-up of the mantle can strongly affect the mechanism of further generation of the toroidal field, specifically, it can enhance the field in a small neighborhood of the rigid-body-rotating core of the supernova remnant.Comment: 8 pages, late

    Efficiency of Electron-Positron Pair Productionby Neutrino Flux from Accretion Disk of a Kerr Black Hole

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    Dominant processes of neutrino production and neutrino-induced \ep-pair production are examined in the model of a disk hyper-accreting onto a Kerr black hole. The efficiency of plasma production by a neutrino flux from the disk, obtained for the both cases of presence and absence of a magnetic field, is found to be no more than several tenths of percent and, therefore, not enough for the origin of cosmological gamma-ray bursts.Comment: 8 pages, 1 figur

    Minimally invasive surgery parenchymal cysts abdominal children

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    Retrospectively and prospectively studied 53 clinical cases of surgical treatment of cystic formations of parenchpal abdominal organs in children. Experience in treatment of cysts various minimally invasive techniques. The most efficient and optimal results are achieved with laparoscopic fenestration of cysts in conjunction with argon plasma deepitelizatsii inner lining.Ретроспективно и проспективно изучено 53 клинических случая оперативного лечения кистозных образований паренхиматозных органов брюшной полости у детей. Представлен опыт лечения кист различными малоинвазивными методиками. Наиболее эффективные и оптимальные результаты достигнуты при лапароскопической фенестрации кист в сочетании с аргоноплазменной деэпителизацией внутренней выстилки

    Benign bone neoplasm in children in the Sverdlovsk region

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    The article presents a retrospective analysis of patients (children) with benign bone tumors who have received treatment in the Traumathology and Orthopaedics Department of the SAIH "Regional Children's Clinical Hospital" for the last five years, in particular: osteochondroma, osteoidosteoma, chondroma and tumors with intraossal growth. The article presents the options for therapeutic and tactical decisions, various options for bone grafting in 446 patients as well as the long-term results of the treatment.Представлен ретроспективный анализ детей, пролеченных в травматолого-ортопедическом отделении ГАУЗ СО «Областной детской клинической больницы» с доброкачественными образованиями костей за последние пять лет, в частности: остеохондромы, остеоид-остеомы, хондромы и опухоли с интраоссальным ростом. В статье приведены варианты лечебно- тактических решений, различные варианты пластики костной ткани у 446 пациентов, а также отдаленные результаты проведенного лечения

    Surgical managment of liver tumors in children

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    The article presents 23 years’ experience of surgical treatment of liver tumors in pediatric patients in the Sverdlovsk region. Diagnostic methods are highlighted, significance of prophylactic ultrasound examination of children is defined. Options of surgical treatment are noticed, results of mono- and multidisciplinary approach of the cooperative team: pediatric surgeon, transplant surgeon-hepatologist and pediatric cardiac surgeon.В статье представлен 23-летний опыт лечения опухолей печени у детей в Свердловской области. Освещены методы диагностики, определена значимость профилактического сонографического исследования детей. Отражены варианты оперативно-тактических решений, результаты моно- и мультидисциплинарного лечения объединенной бригады: детский хирург, хирург гепатолог-трансплантолог и детский кардиохирург

    Clinical-endoscopic ahd morphological characteristics of ectopic in wall of stomach pancreas in children

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    The result of clinical-morphological examination and treatment of 188 children with ectopic in wall of stomach pancreas is showed. The endoscopic criteria of diagnostics are presented. Authors propose the classification of ectopic pancreas macroscopic kinds. The morphologic image of this malformation is described in details. The kinds of histological structure and forms of ectopic pancreas layer-by-layer localization are determined.Представлен результат клинико-морфологического обследования и лечения 188 детей с зктопией поджелудочной железы в стенку желудка Приведены эндоскопические критерии диагностики и предложена рабочая классификация макроскопических типов ЭПЖ. Подробно описана морфологическая картина данного порока развития. Установлены варианты гистостроения и формы послойной локализации ЗПЖ

    Features of diagnostics and surgical treatment of ovarian tumors in children

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    The purpose of current work was to assess prognostically significant laboratory parameters in patients with ovarian tumors, as well as to determine optimal types of surgical treatment.Целью работы являлись оценка прогностически значимых лабораторных показателей, а также определение наиболее оптимальных видов хирургического лечения пациенток с опухолями яичников
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