491 research outputs found

    Stability of two-dimensional spatial solitons in nonlocal nonlinear media

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    We discuss existence and stability of two-dimensional solitons in media with spatially nonlocal nonlinear response. We show that such systems, which include thermal nonlinearity and dipolar Bose Einstein condensates, may support a variety of stationary localized structures - including rotating spatial solitons. We also demonstrate that the stability of these structures critically depends on the spatial profile of the nonlocal response function.Comment: 8 pages, 9 figure

    Risk factors and clinical and neurological consequences of intraoperative rupture of brain aneurysms in microsurgical operations

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    Objective. to assess the frequency, risk factors and clinical and neurological consequences of intraoperative rupture of arterial aneurysm (AA) of the brain (B) in clipping operations of the B AA . Materials and approaches. A retrospective analysis of microsurgical operations clipping of cerebral aneurysms in 1449 (100%) patients for the period from 2011 to 2018 was performed, of which 141 (9.73%) cases had intraoperative rupture of the aneurysm (IORA). Preoperative examination: clinical and neurological examination, CT of the brain, cerebral angiography( CAG), duplex scanning of the main vessels of the head and neck. The analyzed criteria are risk factors of IORA: AA size, localization, shape, duration of surgery after the primary rupture of AA, the presence of hypertension and the patient's condition before surgery. Results. The frequency of IORA in clipping operations of B AA was 9.73% (141 patients) in a series of observations 1441 (100%). Most often IORA-141 (100%) was registered in clipping operations of AA of complex ACA-AcomA (86 (61%) cases out of 141 (100%)). IORA is possible at all stages of the operation with the maximum frequency of contact breaks – 135 (95.74%); the rarest-6 ( 4.26%)  -  non - contact IORA (at the stage of craniotomy)  was recorded. At the preoperative stage, the vast majority of patients with subsequent IORA were diagnosed with cerebral edema, AA of large size, atherosclerotic changes in the aneurysm-affected segment of the artery and cervical areas of the aneurysm, high blood pressure during surgery, adhesive arachnoid changes. At the time of discharge from the hospital, according to the Glasgow results scale: 69 (48.94%) full or partial restoration of labor activity, 18 (12.77%) had limited daily activities without the need for outside assistance, 37 (26 24%) deep disability ) Deaths were in the group of "contact" IORA -  17 (12.06%). At 6 ( 4.26%) of "non-contact" IORA,  a deepening of initial neurological symptoms was recorded with a suppression of the level of consciousness, the addition of pyramidal insufficiency, speech impairment and psycho-organic syndrome, and a deepening of the phenomena of initial cerebral arterial vasospasm. Conclusions. IORA is predominantly in contact with a frequency of occurrence-9.73 %. The most common risk factors for IORA were: cerebral edema, large AA, atherosclerotic changes in the aneurysm-affected artery segment and cervical aneurysm sites, high blood pressure during surgery, adhesions arachnoid changes. IORA leads to deepening of initial neurological symptoms, phenomena of initial vasospasm of cerebral arteries with the level of total mortality-17 (12.06%)

    Building air leakage databases in energy conservation policies: analysis of selected initiatives in 4 European countries and the USA

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    Fulltext is available at http://tightvent.eu/wp-content/uploads/2012/02/TightVentReport03.pdfWe collected information on existing envelope air leakage databases from countries that are involved in the AIVC-TightVent project “Development and applications of building air leakage databases”. This document summarizes the information from five countries: Czech Republic, France, Germany, UK, and USA. Even though our summary is not exhaustive of all existing data on whole-building envelope air leakage, it provides an overview of recent efforts from a number of countries. There are many reasons why different countries are collecting these data. We will summarize their motivations, which drive some of the differences in the types of data being gathered and how the data are analysed. Detailed information from each country is provided at the end of this document in the form of tables

    Collapse arrest and soliton stabilization in nonlocal nonlinear media

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    We investigate the properties of localized waves in systems governed by nonlocal nonlinear Schrodinger type equations. We prove rigorously by bounding the Hamiltonian that nonlocality of the nonlinearity prevents collapse in, e.g., Bose-Einstein condensates and optical Kerr media in all physical dimensions. The nonlocal nonlinear response must be symmetric, but can be of completely arbitrary shape. We use variational techniques to find the soliton solutions and illustrate the stabilizing effect of nonlocality.Comment: 4 pages with 3 figure

    Tracking azimuthons in nonlocal nonlinear media

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    We study the formation of azimuthons, i.e., rotating spatial solitons, in media with nonlocal focusing nonlinearity. We show that whole families of these solutions can be found by considering internal modes of classical non-rotating stationary solutions, namely vortex solitons. This offers an exhaustive method to identify azimuthons in a given nonlocal medium. We demonstrate formation of azimuthons of different vorticities and explain their properties by considering the strongly nonlocal limit of accessible solitons.Comment: 11 pages, 7 figure

    Modulational instability, solitons and beam propagation in spatially nonlocal nonlinear media

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    We present an overview of recent advances in the understanding of optical beams in nonlinear media with a spatially nonlocal nonlinear response. We discuss the impact of nonlocality on the modulational instability of plane waves, the collapse of finite-size beams, and the formation and interaction of spatial solitons.Comment: Review article, will be published in Journal of Optics B, special issue on Optical Solitons, 6 figure

    Increasing Detection Performance of Surveillance Sensor Networks

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    We study a surveillance wireless sensor network (SWSN) comprised of small and low-cost sensors deployed in a region in order to detect objects crossing the field of interest. In the present paper, we address two problems concerning the design and performance of an SWSN: optimal sensor placement and algorithms for object detection in the presence of false alarms. For both problems, we propose explicit decision rules and efficient algorithmic solutions. Further, we provide several numerical examples and present a simulation model that combines our placement and detection methods

    Carbonization and Regeneration of Mo/ZSM-5 Catalysts for Methane Dehydroaromatization

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    The character of carbonaceous deposits formed during methane dehydroaromatization reaction in the presence of Mo/ZSM-5 catalysts was studied by differential thermal analysis. The dependence of the concentration and condensation degree (C/H ratio) of the carbonaceous deposits on the catalyst synthesis conditions (Mo content = 1-10%, Si/Al ratio in the initial H-ZSM-5 = 17-45) and reaction conditions (feed flow rate = 405-1620 h-1, methane concentration = 90-98%, reaction temperature = 720-780 °C) was investigated. The oxidative treatment conditions of carbonized Mo/ZSM-5 catalysts providing stable operation of the catalysts under multiple reaction-oxidative treatment cycles were selected

    Response to comment on "preserved feedforward but impaired top-down processes in the vegetative state".

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    King et al. raise some technical issues about our recent study showing impaired top-down processes in the vegetative state. We welcome the opportunity to provide more details about our methods and results and to resolve their concerns. We substantiate our interpretation of the results and provide a point-by-point response to the issues raised.Peer reviewe

    The physics of dipolar bosonic quantum gases

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    This article reviews the recent theoretical and experimental advances in the study of ultracold gases made of bosonic particles interacting via the long-range, anisotropic dipole-dipole interaction, in addition to the short-range and isotropic contact interaction usually at work in ultracold gases. The specific properties emerging from the dipolar interaction are emphasized, from the mean-field regime valid for dilute Bose-Einstein condensates, to the strongly correlated regimes reached for dipolar bosons in optical lattices.Comment: Review article, 71 pages, 35 figures, 350 references. Submitted to Reports on Progress in Physic
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