211 research outputs found

    Memory Effects and Scaling Laws in Slowly Driven Systems

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    This article deals with dynamical systems depending on a slowly varying parameter. We present several physical examples illustrating memory effects, such as metastability and hysteresis, which frequently appear in these systems. A mathematical theory is outlined, which allows to show existence of hysteresis cycles, and determine related scaling laws.Comment: 28 pages (AMS-LaTeX), 18 PS figure

    Fe/TiO2 composite coatings: electrodeposition and application for photo-catalytic dye degradation

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    The electrodeposition of iron-titania composite coatings from a methanesulfonate plating bath is studied in this work. The TiO2 content in deposits is shown to increase with increasing titania concentration in suspension electrolyte and decreasing cathode current density. The kinetics of composite Fe/TiO2 electrodeposition obeys the model proposed by Guglielmi. The photo-catalytic activity of synthesized Fe/TiO2 composite electrochemical coatings was estimated in the model reaction of decomposition of Methyl Orange dye in an alkaline solution. The use of the Fe/TiO2 composite electroplated films as a photo-catalyst allows accelerating the decomposition of Methyl Orange dye in aqueous media under the action of UV radiation

    Noise studies of magnetization dynamics in dilute magnetic semiconductor heterostructures

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    We study theoretically and experimentally the frequency and temperature dependence of resistivity noise in semiconductor heterostructures delta-doped by Mn. The resistivity noise is observed to be non-monotonous as a function of frequency. As a function of temperature, the noise increases by two orders of magnitude for a resistivity increase of about 50%. We study two possible sources of resistivity noise -- dynamic spin fluctuations and charge fluctuations, and find that dynamic spin fluctuations are more relevant for the observed noise data. The frequency and temperature dependence of resistivity noise provide important information on the nature of the magnetic interactions. In particular, we show how noise measurements can help resolve a long standing debate on whether the Mn-doped GaAs is an p-d Zener/RKKY or double exchange ferromagnet. Our analysis includes the effect of different kinds of disorder such as spin-glass type of interactions and a site-dilution type of disorder. We find that the resistivity noise in these structures is well described by a disordered RKKY ferromagnet model dynamics with a conserved order parameter.Comment: 15 pages, 7 eps figures, published versio

    Polarity and structure of 2-(1-methylbenzimidazol-2-yl)-1-phenyl- and -1,2-diphenyl-1-nitroethenes

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    Polarity of 2-(1-methylbenzimidazol-2-yl)-1-phenyl- and -1,2-diphenyl-1-nitroethenes was determined and their structure was studied using electronic and 1H, 13C NMR spectroscopy, dipole moments measuring, XRD analysis, and quantum-chemical calculations. It was shown that the 2-(1-methylbenzimidazol-2-yl)-1-nitro-1-phenylethene has Z-configuration both in crystal and solution. The nitro group and benzimidazole substituent in its molecule are removed from the plane of the double bond. For 1,2-diphenyl-1-nitroethene E-structure is typical. © 2012 Pleiades Publishing, Ltd

    Клинические варианты кашлевого рефлекса и их коррекция

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    Cough is one of the commonest causes of seeking for medical aid. Cough, especially chronic cough, significantly reduces quality of life, disturbs sleep, physical and intellectual activity. Given the fact that cough is not an independent disease, but is a clinical sign (often the only sign) of a disease or a condition, attempts to resolve this symptom without specifying the nature of cough are incorrect. Unfortunately, the cause of cough cannot be established in some cases; patients suffering from chronic cough of unknown etiology account for 10 to 38% and are treated symptomatically even in countries with a high level of medicine. Physicians should aware of that the therapeutic success is always a result of correct diagnostic work-up.Кашель является одной из самых частых причин обращений к врачу общей практики. При кашле, в особенности хроническом, существенно снижается качество жизни пациентов, нарушается сон, физическая и интеллектуальная активность. С учетом того, что кашель – не самостоятельное заболевание, а клинический симптом (нередко единственный) какого-либо заболевания или патологического состояния, попытки устранения этого симптома без уточнения природы кашля ошибочны. К сожалению, в ряде случаев причину кашля установить не удается: даже в странах с высоким уровнем диагностики пациенты, страдающие хроническим кашлем неясной этиологии, составляют от 10 до 38 % и лечатся, как правило, симптоматически. Нужно иметь в виду, что успех от назначенной терапии всегда есть результат грамотно проведенной диагностики основного заболевания

    Protestant women in the late Soviet era: gender, authority, and dissent

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    At the peak of the anti-religious campaigns under Nikita Khrushchev, communist propaganda depicted women believers as either naïve dupes, tricked by the clergy, or as depraved fanatics; the Protestant “sektantka” (female sectarian) was a particularly prominent folk-devil. In fact, as this article shows, women’s position within Protestant communities was far more complex than either of these mythical figures would have one believe. The authors explore four important, but contested, female roles: women as leaders of worship, particularly in remote congregations where female believers vastly outnumbered their male counterparts; women as unofficial prophetesses, primarily within Pentecostal groups; women as mothers, replenishing congregations through high birth rates and commitment to their children’s religious upbringing; and women as political actors in the defence of religious rights. Using a wide range of sources, which include reports written by state officials, articles in the church journal, letters from church members to their ecclesiastical leaders in Moscow, samizdat texts, and oral history accounts, the authors probe women’s relationship with authority, in terms of both the authority of the (male) ministry within the church, and the authority of the Soviet state

    РОССИЙСКОЕ РЕСПИРАТОРНОЕ ОБЩЕСТВО ФЕДЕРАЛЬНЫЕ КЛИНИЧЕСКИЕ РЕКОМЕНДАЦИИ ПО ДИАГНОСТИКЕ И ЛЕЧЕНИЮ БРОНХИАЛЬНОЙ АСТМЫ

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    Asthma is a chronic inflammatory airway disease with bronchial hyperresponsivenes causing recurrent episodes of wheezing, dyspnea, chest tightness and cough which typically occur at nighttime or early in the morning. These episodes are due to generalized airway obstruction which is commonly reversible spontaneously or with treatment. Asthma is mainly diagnosed clinically and should be based on the patient's symptoms and signs, lung function testing with investigations of bronchial obstruction reversibility, allergy testing and after exclusion of other diseases. The aim of asthma therapy is achievement and maintenance of asthma control that is maximal resolution of clinical symptoms of the disease.Бронхиальная астма (БА) – хроническое воспалительное заболевание дыхательных путей с развитием бронхиальной гиперреактивности, которая обусловливает повторяющиеся эпизоды свистящих хрипов, одышки, чувства заложенности в груди и кашля, в особенности по ночам или ранним утром. Эти эпизоды связаны с распространенной обструкцией дыхательных путей, которая часто бывает обратимой спонтанно или под влиянием лечения. Диагноз БА является клиническим и устанавливается на основании жалоб и анамнеза пациента, клинико-функционального обследования с оценкой обратимости бронхиальной обструкции, специфического аллергологического обследования и при исключении других заболеваний. Целью лечения стабильной БА является достижение и поддержание контроля над симптомами БА, другими словами, максимальное устранение клинических проявлений заболевания
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