Anomalous Zero Sound

We show that the anomalous term in the current, recently suggested by Son and Yamamoto, modifies the structure of the zero sound mode in the Fermi liquid in a magnetic field.Comment: 14 pages, 2 figure

Поведение морфолина и его триметилсилилпроизводного в реакциях с триметилсилилизоцианатом

Objectives. To study the patterns of behavior of morpholine and its trimethylsilyl derivative in reactions with trimethylsilyl isocyanate.Methods. The study employed infrared and nuclear magnetic resonance spectroscopy, as well as elemental analysis.Results. The formation of mixtures of tautomeric forms of silicon-containing urea—N-(trimethylsilyl) morpholine-4-carboxamide and trimethylsilylmorpholine-4-carboximidoate—was established.Conclusions. It is shown that the composition and structure of the resulting products are determined both by the presence of a morpholine substituent at the nitrogen atom and by the type of isocyanate used. Unlike the trimethylsilyl derivative of morpholine, morpholine itself reacts with trimethylsilyl isocyanate to form a mixture of tautomeric forms.Цели. Изучить закономерности поведения морфолина и его триметилсилилпроизводного в реакциях с триметилсилилизоцианатом.Методы. В исследовании использовались методы инфракрасной спектроскопии, спектроскопии ядерного магнитного резонанса и элементного анализа.Результаты. Установлено образование смеси таутомерных форм кремнийсодержащей мочевины: N-(триметилсилил)морфолин-4-карбоксамида и триметилсилилморфолин -4-карбоксимидоата.Выводы. Установлено, что состав и строение образующихся продуктов определяется как наличием заместителя при атоме азота морфолина, так и типом используемого изоцианата. Показано, что, в отличие от триметилсилильного производного морфолина, сам морфолин взаимодействует с триметилсилилизоцианатом с образованием смеси таутомерных форм

Thermal processes of thermokarst lakes in the continuous permafrost zone of northern Siberia - observations and modeling (Lena River Delta, Siberia)

© Author(s) 2015. Thermokarst lakes are typical features of the northern permafrost ecosystems, and play an important role in the thermal exchange between atmosphere and subsurface. The objective of this study is to describe the main thermal processes of the lakes and to quantify the heat exchange with the underlying sediments. The thermal regimes of five lakes located within the continuous permafrost zone of northern Siberia (Lena River Delta) were investigated using hourly water temperature and water level records covering a 3-year period (2009-2012), together with bathymetric survey data. The lakes included thermokarst lakes located on Holocene river terraces that may be connected to Lena River water during spring flooding, and a thermokarst lake located on deposits of the Pleistocene Ice Complex. Lakes were covered by ice up to 2 m thick that persisted for more than 7 months of the year, from October until about mid-June. Lake-bottom temperatures increased at the start of the ice-covered period due to upward-directed heat flux from the underlying thawed sediment. Prior to ice break-up, solar radiation effectively warmed the water beneath the ice cover and induced convective mixing. Ice break-up started at the beginning of June and lasted until the middle or end of June. Mixing occurred within the entire water column from the start of ice break-up and continued during the ice-free periods, as confirmed by the Wedderburn numbers, a quantitative measure of the balance between wind mixing and stratification that is important for describing the biogeochemical cycles of lakes. The lake thermal regime was modeled numerically using the FLake model. The model demonstrated good agreement with observations with regard to the mean lake temperature, with a good reproduction of the summer stratification during the ice-free period, but poor agreement during the ice-covered period. Modeled sensitivity to lake depth demonstrated that lakes in this climatic zone with mean depths > 5 m develop continuous stratification in summer for at least 1 month. The modeled vertical heat flux across the bottom sediment tends towards an annual mean of zero, with maximum downward fluxes of about 5 W m-2 in summer and with heat released back into the water column at a rate of less than 1 W m-2 during the ice-covered period. The lakes are shown to be efficient heat absorbers and effectively distribute the heat through mixing. Monthly bottom water temperatures during the ice-free period range up to 15 °C and are therefore higher than the associated monthly air or ground temperatures in the surrounding frozen permafrost landscape. The investigated lakes remain unfrozen at depth, with mean annual lake-bottom temperatures of between 2.7 and 4 °C

ОСОБЕННОСТИ ВЗАИМОДЕЙСТВИЯ ИЗОЦИАНАТОВ С ПРОИЗВОДНЫМИ ГИДРАЗИНА

The results of studies on chemical transformations of organic and organosilicon isocyanates in their interaction with hydrazine derivatives have been summarized in this review. It is shown that hydrazine and its derivatives including organosilicon compounds reacting with organic isocyanates form corresponding semicarbazides readily enough. The reaction conditions that effect the composition, structure and yield of the resulting target products are presented. A significant difference in the interaction of trimethylsilyl isocyanate with organic and organosilicon derivatives of hydrazine is demonstrated. It is demonstrated that the reason for the impossibility to isolate trimethylsilyl derivatives of semicarbazide is their low hydrolytic stability, as well as high silylating ability. Peculiarities of the reaction of trimethylsilyl isocyanate and dimethylchloromethyl isocyanate silane with 1,1-dimethylhydrazine, its trimethylsilyl analog and isoniazid are given. Possible schemes for the formation of a previously unknown O-trimethylsilyl-1,1-dimethylhydrazinecarboximidoate are presented. The results of using carbofunctional organosilicon isocyanates in these processes are discussed. Basic trends in practical use of the prepared compounds as physiologically active preparations in polymer chemistry and agriculture are shown.В обзоре обобщены результаты исследований по изучению химических превращений органических и кремнийорганических изоцианатов при их взаимодействии с производными гидразина. Показано, что с органическими изоцианатами гидразин и его производные, в том числе и кремнийорганические, достаточно легко образуют соответствующие семикарбазиды. Приведены условия проведения реакций, оказывающие влияние на состав, строение и выход образующихся целевых продуктов. Показано существенное отличие взаимодействия триметилсилилизоцианата с органическими и кремнийорганическими производными гидразина. Показано, что причиной невозможности выделения триметилсилильных производных семикарбазида является их низкая гидролитическая стабильность, а также высокая силилирующая способность. Обсуждены особенности реакций взаимодействия триметилсилилизоцианата и диметилхлорметилизоцианатосилана с 1,1-диметилгидразином, его триметилсилилным аналогом и изониазидом. Приведены возможные варианты схем образования ранее неизвестного О-триметилсилил-1,1-диметилгидразинкарбоксимидоата. Показаны результаты использования в данных процессах карбофункциональных кремнийорганических изоцианатов. Представлены основные направления практического использования получаемых соединений - в качестве физиологически активных препаратов, в полимерной химии и в сельском хозяйстве

Chiral drag force

We provide a holographic evaluation of novel contributions to the drag force acting on a heavy quark moving through strongly interacting plasma. The new contributions are chiral in that they act in opposite directions in plasmas containing an excess of left- or right-handed quarks and in that they are proportional to the coefficient of the axial anomaly. These new contributions to the drag force act either parallel to or antiparallel to an external magnetic field or to the vorticity of the fluid plasma. In all these respects, these contributions to the drag force felt by a heavy quark are analogous to the chiral magnetic effect on light quarks. However, the new contribution to the drag force is independent of the electric charge of the heavy quark and is the same for heavy quarks and antiquarks. We show that although the chiral drag force can be non-vanishing for heavy quarks that are at rest in the local fluid rest frame, it does vanish for heavy quarks that are at rest in a suitably chosen frame. In this frame, the heavy quark at rest sees counterpropagating momentum and charge currents, both proportional to the axial anomaly coefficient, but feels no drag force. This provides strong concrete evidence for the absence of dissipation in chiral transport, something that has been predicted previously via consideration of symmetries. Along the way to our principal results, we provide a general calculation of the corrections to the drag force due to the presence of gradients in the flowing fluid in the presence of a nonzero chemical potential. We close with a consequence of our result that is at least in principle observable in heavy ion collisions, namely an anticorrelation between the direction of the CME current for light quarks in a given event and the direction of the kick given to the momentum of all the heavy quarks and antiquarks in that event.Comment: 28 pages, small improvement to the discussion of gravitational anomaly, references adde

КВАНТОВО-ХИМИЧЕСКИЙ АНАЛИЗ СТРУКТУРООБРАЗОВАНИЯ КАРКАСНЫХ ОРГАНОСИЛОКСАНОВ И МЕТАЛЛООРГАНОСИЛОКСАНОВ

Several ab initio (DFT-B3PW91/6-31g(d,p)) calculations of cage-like siloxanes (MeSiO1.5)n (n = 4-12) have been made. It was shown that cubane-like structure (MeSiO1.5)8 is the most stable one. Refined mechanism of polymeric metallasiloxanes cleavage by the silanolates has been suggested. It has been shown that isomerisation of Cu-containing siloxanes (rearrangement of sandwich-like form into globule-like form) is mostly governed by the coordination properties of solvates.Квантово-химическими расчетами каркасных органосилсесквиоксанов показано, что наибольшей стабильностью обладает кубановая структура (MeSiO1.5)8. Проведено уточнение механизма расщепления олигомерных металлоорганосилоксанов органосиланолятами щелочных ме-таллов, предложена схема синтеза. На основании расчетов предположено, что реакции металлсодержащих силоксанов определяются координирующим влиянием растворителей

Диагностика и мониторинг нейронального повреждения при тяжелой черепно-мозговой травме

Objective: to search for an accessible, valid, and easy-to-use method for the diagnosis and monitoring of a neuronal lesion in severe brain injury (SBI). Subjects and methods. Thirty-three patients aged 18—55 years with isolated SBI (the Glasgow coma scores for admission consciousness were 6±2) were examined; the serum content of neuron-specific protein S-100B was further analyzed. Results and discussion. The cell damage marker concentration was substantially increased in the acute period of brain injury. When the pathological process followed a favorable course, S-100B was considerably decreased just on day 2 of the disease. When the changes were negative, S-100B concentrations remained virtually unchanged or even increased, which was indicative of secondary brain reperfusion/ischemic lesions. The mean baseline marker level varied with the type of brain injury diagnosed by computed tomography; the highest figures being noted in the groups where significant brain tissue lesion was detected. Key words: severe brain injury, prognosis, S-100B protein.Цель исследования — поиск доступного, надежного и простого метода диагностики и мониторинга нейронального повреждения при ТЧМТ. Материалы и методы. Проведено обследование 33 пациентов с изолированной ТЧМТ в возрасте 18—55 лет (уровень сознания при поступлении в стационар 6±2 балла по ШКГ), с последующим анализом содержания нейронспецифического протеина S-100В в сыворотке крови. Результаты и обсуждение. Концентрация маркера клеточного повреждения значительно повышалась в остром периоде черепно-мозговой травмы. При благоприятном течении патологического процесса уровень S-100В значительно снижался уже на 2-е сутки болезни. При отрицательной динамике концентрация S-100В оставалась практически неизменной или даже повышалась, что свидетельствовало о вторичных реперфузионных повреждениях головного мозга. Показано, что средние значения начального уровня маркера различались в зависимости от вида ЧМТ, диагностированного КТ, причем наибольшие цифры отмечались в группах, где выявлялось значительное повреждение мозговой ткани. Ключевые слова: тяжелая черепно-мозговая травма, прогноз, белок S-100В

Quantum Gravity in Everyday Life: General Relativity as an Effective Field Theory

This article is meant as a summary and introduction to the ideas of effective field theory as applied to gravitational systems. Contents: 1. Introduction 2. Effective Field Theories 3. Low-Energy Quantum Gravity 4. Explicit Quantum Calculations 5. ConclusionsComment: 56 pages, 2 figures, JHEP style, Invited review to appear in Living Reviews of Relativit