103 research outputs found
Применение Беспилотных Летательных Аппаратов Для Оценки Качества Растительности
The use of Earth remote sensing (ERS) in agriculture is related with inventory of arable areas, detection of soil erosion, bogging. At present great attention is paid to studies devoted to determination of productivity of arable areas based on ERS data under various climatic conditions. Satellite images are characterized by certain drawbacks such as low resolution, impossibility to acquire images from behind clouds. A promising approach to obtain high precision maps is the use of unmanned aerial vehicles (UAV).The degree of crop development is estimated by their NDVI which is used in numerous photometric instruments for diagnostics of plant nitrogenous nutrition. With this aim, the UAV camera detects plant reflection intensity of sunlight or induced light in red (P NIR) and infrared (P RED) spectra. Thus, it becomes necessary to determine mechanisms and interrelation of vegetation index which would permit to obtain data on crop productivity on the basis of data from UAV.Использование данных дистанционного зондирования Земли (ДДЗ) в сельском хозяйстве связано с инвентаризацией сельхозугодий, обнаружением эрозии почвы, заболачивания. В последние годы большой интерес приобретают исследования, направленные на выявления урожайности сельскохозяйственных культур с данными ДДЗ в различных климатических условиях. Использование космических снимков имеет ряд недостатков, таких как: низкое разрешение, невозможность получения их из-за облаков. Одним из перспективных путей решения получения высокоточных карт является применение беспилотных летательных аппаратов (БПЛА). Для оценки степени развития посевов обычно применяют их вегетационный NDVI, который используется во многих фотометрических приборах для диагностики азотного питания растений. Для этого в фотокамере БПЛА предусмотрена фиксация интенсивности отражения растениями солнечного или индуцированного света в красной (P NIR) и инфракрасной (P RED) областях спектра. Исходя из этого возникает необходимость проведения в исследований по выявлению механизмов и взаимосвязи вегетационного индекса, что позволит получать информацию о продуктивности сельскохозяйственных культур, используя данные с беспилотного летательного аппарата
LARGE AREA HODOSCOPES FOR MUON DIAGNOSTICS OF HELIOSPHERE AND EARTH'S MAGNETOSPHERE
Muon diagnostics is a technique for remote monitoring of active processes in the heliosphere and the magnetosphere of the Earth based on the analysis of angular variations of muon flux simultaneously detected from all directions of the upper hemisphere. To carry out muon diagnostics, special detectors – muon hodoscopes – which can detect muons from any direction with good angular resolution in real-time mode are required. We discuss approaches to data analysis and the results of studies of various extra-terrestrial processes detected by means of the wide aperture URAGAN muon hodoscope
Myectomy versus alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy
OBJECTIVES: There is very little evidence comparing the safety and efficacy of alcohol septal ablation versus septal myectomy for a septal reduction in patients with hypertrophic obstructive cardiomyopathy. This study aimed to compare the immediate and long-term outcomes of these procedures. METHODS: Following propensity score matching, we retrospectively analysed outcomes in 105 patients who underwent myectomy and 105 who underwent septal ablation between 2011 and 2017 at 2 reference centres. RESULTS: The mean age was 51.9 ± 14.3 and 52.2 ± 14.3 years in the myectomy and ablation groups, respectively (P = 0.855), and postoperative left ventricular outflow tract gradients were 13 (10-19) mmHg vs 16 (12-26) mmHg; P = 0.025. The 1-year prevalence of the New York Heart Association class III-IV was higher in the ablation group (none vs 6.4%; P = 0.041). The 5-year overall survival rate [96.8% (86.3-99.3) after myectomy and 93.5% (85.9-97.1) after ablation; P = 0.103] and cumulative incidence of sudden cardiac death [0% and 1.9% (0.5-7.5), respectively P = 0.797] did not differ between the groups. The cumulative reoperation rate within 5 years was lower after myectomy than after ablation [2.0% (0.5-7.6) vs 14.6% (8.6-24.1); P = 0.003]. Ablation was associated with a higher reoperation risk (subdistributional hazard ratio = 5.9; 95% confidence interval 1.3-26.3, P = 0.020). At follow-up, left ventricular outflow tract gradient [16 (11-20) vs 23 (15-59) mmHg; P < 0.001] and prevalence of 2+ mitral regurgitation (1.1% vs 10.6%; P = 0.016) were lower after myectomy than after ablation. CONCLUSIONS: Both procedures improved functional capacity; however, myectomy better-resolved classes III-IV of heart failure. Septal ablation was associated with higher reoperation rates. Myectomy demonstrated benefits in gradient relief and mitral regurgitation elimination. The results suggest that decreasing rates of myectomy procedures need to be investigated and reconsidered. © The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved
Local anisotropy of muon flux during Forbush decreases from URAGAN data
The approach to the analysis of spatial-angular characteristics of the muon flux variations at different phases of Forbush decrease development according to the muon snapshots (muongraphies) obtained using muon hodoscope URAGAN, as well as the analysis results are presented
Local anisotropy of muon flux during Forbush decreases from URAGAN data
The approach to the analysis of spatial-angular characteristics of the muon flux variations at different phases of Forbush decrease development according to the muon snapshots (muongraphies) obtained using muon hodoscope URAGAN, as well as the analysis results are presented
Temperature effect corrections for URAGAN based on CAO, GDAS, NOAA data
For the analysis of muon flux variations caused by extra-atmospheric processes it is necessary to introduce corrections for meteorological effects. For temperature effect (TE) correction it is necessary to know the temperature profile of the atmosphere. As a rule, this profile is measured by meteorological balloons two or four times a day. Alternative sources are satellite observations and data obtained from models of atmosphere used for weather forecasting. Vertical temperature profiles obtained from NOAA satellites, GDAS (Global Data Assimilation System) and CAO data (Central Aerological Observatory, Russia) for standard isobaric levels were compared. Mean value of temperature difference for most levels does not exceed 1 K. Comparison of URAGAN data corrected for TE with CAO information, satellites and GDAS shows a good agreement. Counting rate and anisotropy of the muon flux corrected for meteorological effects for 2007-2014 are presented
ПОЛУЧЕНИЕ ЛЕГИРОВАННЫХ НИКЕЛИДОВ АЛЮМИНИЯ МЕТАЛЛОТЕРМИЕЙ ОКСИДОВ МЕТАЛЛОВ
Fabrication conditions of NiAl, NiAl–Cr and NiAl–Cr–Mo–W alloys by joint aluminothermic reduction of initial metal oxides are investigated. Thermodynamic characteristics of accompanying reactions are determined. The temperature dependence of the isobaric potential change (ΔG0, kJ/mol) of reduction reactions of oxides point to high formation probability of alloys. It is revealed by differential thermal analysis that the reduction of metal oxides enters the active phase after aluminum is melted at ~650 °C and progresses according to the heterogeneous mechanism in a temperature range of 800–1100 °C. The optimal composition of the initial charge, which provides the maximal yield of metals into alloys, is established. It is found experimentally that the yield of metals into alloys constitutes 85–92 wt.%. Synthesis products are identified by the elemental and X-ray phase analyses as intermetallic compounds of the Ni–Al system, which contain inclusions of chromium, molybdenum, and tungsten. It is shown that the concentration of inclusions varies in a range of 1,5–6,5 wt.%. The microhardness of alloys is determined to vary from 3546 to 7436 MPa depending on the content of alloying elements.Изучены условия получения интерметаллидных сплавов NiAl, NiAl–Cr, NiAl–Cr–Mo–W совместным алюминотермическим восстановлением исходных оксидов металлов. Определены термодинамические характеристики протекающих при этом реакций. Температурная зависимость изменения изобарного потенциала (ΔG0, кДж/моль) реакций восстановления оксидов указывает на высокую вероятность образования сплавов. Методом дифференциального термического анализа выявлено, что восстановление оксидов металлов вступает в активную фазу после расплавления алюминия при ~650 °С и протекает по гетерогенному механизму в интервале температур 800–1100 °С. Установлен оптимальный состав исходной шихты, обеспечивающий максимальный выход металлов в сплавы. Экспериментально найдено, что выход металлов в сплавы составляет 85–92 мас.%. Продукты синтеза идентифицированы элементным и рентгенофазовым методами анализа как интерметаллиды системы NiAl, содержащие включения хрома, молибдена, вольфрама. Показано, что концентрация включений варьируется в пределах 1,5–6,5 мас.%. Определена микротвердость сплавов, которая изменяется от 3546 до 7436 МПа в зависимости от содержания легирующих элементов
Myectomy versus alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy
Tunka Advanced Instrument for cosmic rays and Gamma Astronomy
The paper is a script of a lecture given at the ISAPP-Baikal summer school in
2018. The lecture gives an overview of the Tunka Advanced Instrument for cosmic
rays and Gamma Astronomy (TAIGA) facility including historical introduction,
description of existing and future setups, and outreach and open data
activities.Comment: Lectures given at the ISAPP-Baikal Summer School 2018: Exploring the
Universe through multiple messengers, 12-21 July 2018, Bol'shie Koty, Russi
Meshalkin National Medical Research Center
We present three cases of successful transatrial transcatheter valve-in-valve implantation in patients with bioprosthetic mitral valve dysfunction. Patients with a high surgical risk, with severe heart failure due to bioprosthetic mitral valve dysfunction, were implanted with transcatheter prostheses using the transatrial approach.Transesophageal echocardiography and fluoroscopy-guided transcatheter mitral prosthetic valve positioning was performed. With a cardiac pacing at 180 bpm, a transcatheter valve was implanted. The transcatheter valves functioned properly after surgery. The patients were discharged in satisfactory condition
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