315 research outputs found

    Thermal noise of folding mirrors

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    Current gravitational wave detectors rely on the use of Michelson interferometers. One crucial limitation of their sensitivity is the thermal noise of their optical components. Thus, for example fluctuational deformations of the mirror surface are probed by a laser beam being reflected from the mirrors at normal incidence. Thermal noise models are well evolved for that case but mainly restricted to single reflections. In this work we present the effect of two consecutive reflections under a non-normal incidence onto mirror thermal noise. This situation is inherent to detectors using a geometrical folding scheme such as GEO\,600. We revise in detail the conventional direct noise analysis scheme to the situation of non-normal incidence allowing for a modified weighting funtion of mirror fluctuations. An application of these results to the GEO\,600 folding mirror for Brownian, thermoelastic and thermorefractive noise yields an increase of displacement noise amplitude by 20\% for most noise processes. The amplitude of thermoelastic substrate noise is increased by a factor 4 due to the modified weighting function. Thus the consideration of the correct weighting scheme can drastically alter the noise predictions and demands special care in any thermal noise design process

    Lower Temperature Annealing of Vapor Diffused Nb\u3csub\u3e3\u3c/sub\u3eSn for Accelerator Cavities

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    Nb3Sn is a next-generation superconducting material for the accelerator cavities with higher critical temperature and superheating field, both twice compared to Nb. It promises superior performance and higher operating temperature than Nb, resulting in significant cost reduction. So far, the Sn vapor diffusion method is the most preferred and successful technique to coat niobium cavities with Nb3Sn. Although several post-coating techniques (chemical, electrochemical, mechanical) have been explored to improve the surface quality of the coated surface, an effective process has yet to be found. Since there are only a few studies on the post-coating heat treatment at lower temperatures, we annealed Nb3Sn-coated samples at 800 C - 1000 C to study the effect of heat treatments on surface properties, primarily aimed at removing surface Sn residues. This paper discusses the systematic surface analysis of coated samples after annealing at temperatures between 850 C and 950 C

    Efficacy of antiholinesterase therapy in alcoholic poliencephalopathy

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    68 patients with alcoholic encephalopolyneuropathy, aged from 30 to 60 years, were enrolled in the study. Patients were divided into two groups: 33 patients in the treatment group received vasoactive, antioxidant treatment and neyromidin in dose 15 mg in solution during 10 days and then in tabs in dose 20 mg three times a day during 2 months. The comparison group included 35 patients receiving only vasoactive and antioxidant treatment. To the end of treatment, the positive changes in the state of patients reflected in the decrease in the number of complaints and neurological symptoms were seen in the treatment group. The significant improvement of MMSE scores, positive changes in P300 latency and amplitude, the increase in scores on physical activity scales, emotional functioning, mental health scales of SF-36 questionnaire were found as well. There were no serious treatment-emergent adverse events.Обследовали 68 пациентов 30-60 лет с диагнозом алкогольнойэнцефалополиневропатии. Они были разделены на 2 группы: 33 больным основной группы на фоне вазоактивной и антиоксидантной терапии был назначен раствор нейромидина в дозе 15 мг внутримышечно в течение 10 дней, далее нейромидин в таблетках по 20 мг 3 раза в день в течение 2 мес. В группу сравнения вошли 35 больных, получавших только вазоактивную и антиоксидантную терапию. По сравнению с этой группой в основной группе к концу лечения нейромидином отмечена положительная динамика в состоянии больных, выразившаяся в уменьшении числа жалоб и неврологических симптомов. После терапии нейромидином выявлено также достоверно значимое улучшение показателей по шкале Бека, MMSE, теста 10 слов Лурия, положительная динамика по показателям латентного периода и амплитуды волны Р300 вызванных потенциалов, повышение показателей по субшкалам опросника качества жизни SF-36 - общего здоровья, физического и психического функционирования, улучшение функционального состояния периферической нервной системы. Нежелательных явлений, потребовавших отмены препарата, в ходе лечения нейромидином зарегистрировано не было

    Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

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    Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

    Синдром Миллера Фишера, развившийся после перенесенной инфекции COVID-19 (клинический случай)

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    Miller Fisher syndrome is one of the forms of Guillain–Barrе́ syndrome, characterized by a clinical triad that includes ophthalmoplegia, ataxia and areflexia, with the possible addition of moderate peripheral tetraparesis. During the year that has passed since the start of the pandemic of the new coronavirus infection COVID‑19, international publications have presented a few cases of Miller Fisher syndrome, which developed in patients at different times after the COVID‑19 infection – from 3–5 days to 3 weeks. The article presents a description of a clinical case of Miller Fisher syndrome, which occurred with 34‑year‑old man 21 days after the COVID‑19 infection. The clinical manifestations of Miller Fisher syndrome were typical and included diplopia, areflexia, and ataxia. At the beginning of the disease, there was a transient episode of speech impairment in the form of mild dysarthria. Oculomotor disorders predominated in the clinical picture over other components of the classical triad. On the background of treatment with human immunoglobulin G, there was a complete regression of symptoms.This description of Miller Fisher syndrome, which developed after the postponed infection with COVID‑19, is the first in Russia. The presented case demonstrates the ability of the SARS‑CoV‑2 virus to induce the development of an autoimmune disease. Practitioners should take into account the possibility of Miller Fisher syndrome developing in the event of an acute onset of diplopia, ataxia and areflexia in patients after a previous COVID‑19 infection.Синдром Миллера Фишера – одна из форм синдрома Гийена–Барре, характеризующаяся клинической триадой, которая включает офтальмоплегию, атаксию и арефлексию, с возможным присоединением умеренно выраженного периферического тетрапареза. В течение года, прошедшего с момента начала пандемии новой коронавирусной инфекции COVID‑19, в международных публикациях представлены немногочисленные случаи синдрома Миллера Фишера, развившегося у пациентов в разные сроки после перенесенной инфекции COVID‑19 – от 3–5 дней до 3 нед. В статье представлено описание клинического случая синдрома Миллера Фишера, который возник у мужчины 34 лет через 21 день после перенесенной инфекции COVID‑19. Клинические проявления синдрома Миллера Фишера были типичными и включали диплопию, арефлексию и атаксию. В начале заболевания был преходящий эпизод нарушения речи в виде легкой дизартрии. Глазодвигательные нарушения преобладали в клинической картине над другими составляющими классической триады. На фоне лечения человеческим иммуноглобулином G произошел полный регресс симптомов.Данное описание синдрома Миллера Фишера, развившегося после перенесенной инфекции COVID‑19, является первым в России. Представленный случай демонстрирует способность вируса SARS‑CoV‑2 индуцировать развитие аутоиммунного заболевания. Практическим врачам необходимо учитывать возможность развития синдрома Миллера Фишера в случае острого возникновения диплопии, атаксии и арефлексии у пациентов после перенесенной инфекции COVID‑19

    First Measurement of Coherent Elastic Neutrino-Nucleus Scattering on Argon

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    We report the first measurement of coherent elastic neutrino-nucleus scattering (\cevns) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two independent analyses prefer \cevns over the background-only null hypothesis with greater than 3σ3\sigma significance. The measured cross section, averaged over the incident neutrino flux, is (2.2 ±\pm 0.7) ×\times1039^{-39} cm2^2 -- consistent with the standard model prediction. The neutron-number dependence of this result, together with that from our previous measurement on CsI, confirms the existence of the \cevns process and provides improved constraints on non-standard neutrino interactions.Comment: 8 pages, 5 figures with 2 pages, 6 figures supplementary material V3: fixes to figs 3,4 V4: fix typo in table 1, V5: replaced missing appendix, V6: fix Eq 1, new fig 3, V7 final version, updated with final revision

    Towards a More Complete and Accurate Experimental Nuclear Reaction Data Library (EXFOR): International Collaboration Between Nuclear Reaction Data Centres (NRDC)

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    The International Network of Nuclear Reaction Data Centres (NRDC) coordinated by the IAEA Nuclear Data Section (NDS) is successfully collaborating in the maintenance and development of the EXFOR library. As the scope of published data expands (e.g., to higher energy, to heavier projectile) to meet the needs from the frontier of sciences and applications, it becomes nowadays a hard and challenging task to maintain both completeness and accuracy of the whole EXFOR library. The paper describes evolution of the library with highlights on recent developments.Comment: 4 pages, 2 figure

    Demonstration of a parity-time symmetry breaking phase transition using superconducting and trapped-ion qutrits

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    Scalable quantum computers hold the promise to solve hard computational problems, such as prime factorization, combinatorial optimization, simulation of many-body physics, and quantum chemistry. While being key to understanding many real-world phenomena, simulation of non-conservative quantum dynamics presents a challenge for unitary quantum computation. In this work, we focus on simulating non-unitary parity-time symmetric systems, which exhibit a distinctive symmetry-breaking phase transition as well as other unique features that have no counterpart in closed systems. We show that a qutrit, a three-level quantum system, is capable of realizing this non-equilibrium phase transition. By using two physical platforms - an array of trapped ions and a superconducting transmon - and by controlling their three energy levels in a digital manner, we experimentally simulate the parity-time symmetry-breaking phase transition. Our results indicate the potential advantage of multi-level (qudit) processors in simulating physical effects, where additional accessible levels can play the role of a controlled environment.Comment: 14 pages, 9 figure
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