Frequency splitting in undulator radiation from solid-state crystalline undulator

The set of frequencies and angular properties of radiation emitted from a solid-state crystalline undulator based on the channeling effect are considered. High-frequency and low-frequency branches of the undulator radiation and the angular distribution of the emitted radiation are analyzed. The ranges of frequencies and angles of radiation emitted from the solid-state crystalline undulator based on the channeling effect are found. The frequency splitting and the energy threshold in the production of undulator radiation are shown and discussed.Comment: 11 pages, 2 figure

A proof-of-concept neural network for inferring parameters of a black hole from partial interferometric images of its shadow

We test the possibility of using a convolutional neural network to infer the inclination angle of a black hole directly from the incomplete image of the black hole's shadow in the $uv$-plane. To this end, we develop a proof-of-concept network and use it to explicitly find how the error depends on the degree of coverage, type of input and coverage pattern. We arrive at a typical error of $10^\circ$ at a level of absolute coverage $1\%$ (for a pattern covering a central part of the $uv$-plane), $0.3\%$ (pattern covering the central part and the periphery, the $0.3\%$ referring to the central part only), and $14\%$ (uniform pattern). These numbers refer to a network that takes both amplitude and phase of the visibility function as inputs. We find that this type of network works best in terms of the error itself and its distribution for different angles. In addition, the same type of network demonstrates similarly good performance on highly blurred images mimicking sources nearing being unresolved. In terms of coverage, the magnitude of the error does not change much as one goes from the central pattern to the uniform one. We argue that this may be due to the presence of a typical scale which can be mostly learned by the network from the central part alone.Comment: 12 pages, 10 figures. For the code and trained models, see https://bitbucket.org/cosmoVlad/neuro-rep

Radiation from relativistic electrons in "light" and in conventional undulators. Classical and quantum approaches

A photon spectrum of undulator radiation (UR) is calculated in the semi-classical approach. The UR intensity spectrum is determined by an electron trajectory in the undulator neglecting by energy losses for radiation. Using the Planck's law, the UR photon spectrum can be calculated from the classical intensity spectrum both for linear and nonlinear regimes. The radiation of an electron in a field of strong electromagnetic wave (radiation in the "light" undulator) is considered in the quantum electromagnetic frame. Comparison of results obtained by both approaches has been shown that UR spectra in the whole cone coincide with high accuracy for the case x<<1. Characteristics of the collimated UR beam were simulated with taking into account the discrete process of photon emission along an electron trajectory in both kinds of undulators

ПОКАЗАТЕЛЬ ОТНОСИТЕЛЬНОГО ОБЪЕМА КРОВИ КАК СРЕДСТВО ПРОФИЛАКТИКИ АРТЕРИАЛЬНОЙ ГИПОТЕНЗИИ В ХОДЕ ГЕМОДИАЛИЗА

Intravascular volume preservation is the first choice measure for the prevention of intradialysis hypotension. At present there are devices that allow continuous monitoring of relative blood volume (RBV) changes during haemodialysis (HD). The aim of this research was to investigate (i) the regularity of RBV curve during haemo- dialysis and (ii) the efficacy of some measures for intravascular volume preservation. In patients with hyperhydration RBV curves were monotone; in all cases relation RBV/ ultrafiltration volume (UF) did not exceed 2,5%/L. In stable patients the RBV curve was immutable in the course of years. Patients with high RBV/UF ratio (&gt;6%/L) formed a high risk group. In these patients stability of RBV was more im- portant and more useful. Isolated UF did not decrease RBV drop, as well as haemodiafiltration online. Albumin administration allows to decrease RBV/UF ratio. After bolus of hypertonic dextrose solution RBV increased for about half of hour. In patients with acute renal injury RBV monitoring was far from reliability in many cases. Целью данной работы было определение закономерностей изменения относительного объема крови (ООК) в ходе гемодиализа и действенности различных мероприятий, направленных на поддержание вну- трисосудистого объема. Отслеживание ООК в ходе гемодиализа явилось действенной мерой как для профилактики интрадиа- лизной гипотензии, так и при отработке «сухого веса». Характер кривой ООК у стабильных пациентов на программном гемодиализе остается неизменным в течение многих лет. Высокое (более 6% на 1 литр) отношение максимального снижения ООК к объему ультрафильтрации (ООК/УФ) позволило выявить группу пациентов, у которых обеднение внутрисосудистого объема является основным механизмом раз- вития артериальной гипотензии в ходе сеансов лечения. Изолированная ультрафильтрация и гемодиа- фильтрация on line не позволили улучшить восполнение внутрисосудистого объема. Введение раство- ра альбумина позволяло снизить темп снижения ООК, а болюсное введение гипертонического раствора глюкозы повышало ООК на срок около получаса. У пациентов с острым повреждением почек показатель ООК не всегда оказывался достоверным.

Problems of Agricultural Policy Adaptation Within Sustainable Development Goals

The paper reveals problems of integrating national policy for increasing agricultural production and ecological consequences, including the important aspect of Russia’s ratification of the Paris Agreement on climate, which provides additional opportunities for a decrease in carbon emissions. Current government programs for agricultural development in Russia, which include but are not limited to production growth and increase in agricultural exports, do not take into account the ecological consequences of such growth. The paper analyzes how the agriculture of Russia has evolved in the recent period (2007-2017) and what amount of greenhouse gas (GHG) emissions it has caused. Although in general emissions exhibited a decreasing trend, it was found that ploughing additional land for crop production had caused a large outburst of emissions from a small amount of land. Using the GLOBIOM partial equilibrium model, two scenarios of Russia's agricultural development until 2030 were formulated. The first one is intensive, with only a small amount of crop area growth but with a 45% increase in yields compared to current levels. The second scenario is an extensive one, with crop area growth of additional 6.4 million hectares and a total yield increase of 24% compared to current levels. Results have shown that crop and meat production increase in both scenarios, but the extensive one involves more emissions from additional ploughed land. To stop these kinds of practices, the recommendations would be to limit the ploughing of additional land and to improve statistical bookkeeping for a more accurate inclusion of land use and respective GHG emissions

Оптимизация конвекционного потока при онлайн гемодиафильтрации

Objective: to evaluate the dependence of the magnitude of convection flow in online hemodiafiltration (OLHDF) on ultrafiltration control method and patients’ individual characteristics. Materials and methods. The study included 36 stable dialysis patients (20 male and 16 female). The substitution rate was conducted manually based on transmembrane pressure (TMP). In some cases, devices with automatic filtration rate control unit AutoSub plus were used. The filtration rate (FR), TMP, blood flow rate (Qb), specific filtration rate (SFR, m/l/min/mm Hg–1 ) were recorded. Results. The maximum SFR in various patients ranged from 0.51 to 0.80 ml/min/mm Hg–1 ; average value was 0.62 ± 0.07 ml/min/mm Hg–1 . There was significant correlation of SFR with hemoglobin level (r = –0.55). SFR reduced during hemodiafiltration (on average – by 23 ± 4%). SFR was significantly affected by Qb (r = 0.70). Maximum SFR was achieved with a TMP of 140–220 mm Hg; with TMP over 250 mm Hg, a decrease in SFR was noted, an increase in Qb was required for further increase in FR. Individual stability of SFR was noted during serial observations; fluctuations in a particular patient did not exceed 10%. Substitution volume for the HDF session was 18.0 ± 3.3 L, the FR/Qb ratio was 24.7 ± 5.2%. Substitution volume of 21 L was not achieved in 17 of 36 patients. The use of automatic FR adjustment system made it possible to increase the substitution volume (SV) by 12–18%. Conclusion. Achieving maximum convection volume in OLHDF requires individualizing treatment parameters. The use of FR automatic control allows maximum possible convection flow.Цель: изучить зависимость величины конвекционного потока при онлайн гемодиафильтрации (олГДФ) от способа управления ультрафильтрацией и индивидуальных особенностей пациентов. Материалы и методы. В исследование были включены 36 пациентов (20 мужчин и 16 женщин), находящихся на лечении программным гемодиализом. Управление скоростью замещения проводилось в ручном режиме на основании показателей трансмембранного давления (ТМД). В ряде случаев использовались аппараты с блоком автоматического управления скоростью фильтрации (СФ) AutoSub plus. Фиксировались СФ, ТМД, скорость кровотока (СК), удельная скорость фильтрации (УСФ, мл/мин/мм рт. ст.–1 ). Результаты. Максимальная УСФ у различных пациентов колебалась в пределах 0,51–0,80 мл/мин/мм рт. ст.–1 , среднее значение составило 0,62 ± 0,07 мл/мин/мм рт. ст.–1 . Была отмечена значимая корреляция УСФ с уровнем гемоглобина (r = –0,55). В течение процедуры отмечалось снижение УСФ (в среднем – на 23 ± 4%). На величину УСФ оказывала существенное влияние СК (r = 0,70). Максимальная УСФ достигалась при ТМД 140–220 мм рт. ст., при ТМД свыше 250 мм рт. ст. отмечалось падение УСФ, и для дальнейшего прироста СФ требовалось увеличение скорости кровотока. При серийных наблюдениях была отмечена индивидуальная стабильность УСФ, колебания у конкретного пациента не превышали 10%. Объем замещения за сеанс ГДФ составил 18,0 ± 3,3 л, соотношение СФ/СК 24,7 ± 5,2%, при этом у 17 из 36 пациентов не был достигнут объем замещения 21 л. Применение автоматической системы регулировки СФ позволяло увеличить объем замещения (ОЗ) на 12–18%. Заключение. Достижение максимального конвекционного объема при олГДФ требует индивидуализации параметров лечения. Применение автоматического управления СФ позволяет обеспечить максимально возможный конвекционный поток