Electrical conductivity of rocks at high pressures and temperatures

The results of studies of the electrical conductivity in the most widely distributed types of igneous rocks, at temperatures of up to 1200 C, at atmospheric pressure, and also at temperatures of up to 700 C and at pressures of up to 20,000 kg/sq cm are described. The figures of electrical conductivity, of activaation energy and of the preexponential coefficient are presented and the dependence of these parameters on the petrochemical parameters of the rocks are reviewed. The possible electrical conductivities for the depository, granite and basalt layers of the Earth's crust and of the upper mantle are presented, as well as the electrical conductivity distribution to the depth of 200 to 240 km for different geological structures

On athermic mechanism of materials radiation embrittlement

To elucidate the mehanisms of radiation embrittlement of materials the temperature dependence of mechanical properties of irradiated materials has been studiedyesBelgorod State Universit

Photometric observations of the supernova 2009nr

We present the results of our UBVRI CCD photometry for the second brightest supernova of 2009, SN 2009nr, discovered during a sky survey with the telescopes of the MASTER robotic network. Its light and color curves and bolometric light curves have been constructed. The light-curve parameters and the maximum luminosity have been determined. SN 2009nr is shown to be similar in light-curve shape and maximum luminosity to SN 1991T, which is the prototype of the class of supernovae Ia with an enhanced luminosity. SN 2009nr exploded far from the center of the spiral galaxy UGC 8255 and most likely belongs to its old halo population. We hypothesize that this explosion is a consequence of the merger of white dwarfs

B-blockers, calcium antagonists, and mortality in stable coronary artery disease: An international cohort study

Aims: The effect of first-line antianginal agents, β-blockers, and calcium antagonists on clinical outcomes in stable coronary artery disease (CAD) remains uncertain. Methods and results We analysed the use of β-blockers or calcium antagonists (baseline and annually) and outcomes in 22 006 stable CAD patients (enrolled 2009–2010) followed annually to 5 years, in the CLARIFY registry (45 countries). Primary outcome was all-cause death. Secondary outcomes were cardiovascular death and the composite of cardiovascular death/non-fatal myocardial infarction (MI). After multivariable adjustment, baseline β-blocker use was not associated with lower all-cause death [1345 (7.8%) in users vs. 407 (8.4%) in non-users; hazard ratio (HR) 0.94, 95% confidence interval (CI) 0.84–1.06; P = 0.30]; cardiovascular death [861 (5.0%) vs. 262 (5.4%); HR 0.91, 95% CI 0.79–1.05; P = 0.20]; or cardiovascular death/non-fatal MI [1272 (7.4%) vs. 340 (7.0%); HR 1.03, 95% CI 0.91–1.16; P = 0.66]. Sensitivity analyses according to β-blocker use over time and to prescribed dose produced similar results. Among prior MI patients, for those enrolled in the year following MI, baseline β-blocker use was associated with lower all-cause death [205 (7.0%) vs. 59 (10.3%); HR 0.68, 95% CI 0.50–0.91; P = 0.01]; cardiovascular death [132 (4.5%) vs. 49 (8.5%); HR 0.52, 95% CI 0.37–0.73; P = 0.0001]; and cardiovascular death/non-fatal MI [212 (7.2%) vs. 59 (10.3%); HR 0.69, 95% CI 0.52–0.93; P = 0.01]. Calcium antagonists were not associated with any difference in mortality. Conclusion In this contemporary cohort of stable CAD, β-blocker use was associated with lower 5-year mortality only in patients enrolled in the year following MI. Use of calcium antagonists was not associated with superior mortality, regardless of history of MI

Optical polarization observations with the MASTER robotic net

We present results of optical polarization observations performed with the MASTER robotic net for three types of objects: gamma-ray bursts, supernovae, and blazars. For the Swift gamma-ray bursts GRB100906A, GRB110422A, GRB121011A, polarization observations were obtained during very early stages of optical emission. For GRB100906A it was the first prompt optical polarization observation in the world. Photometry in polarizers is presented for Type Ia Supernova 2012bh during 20 days, starting on March 27, 2012. We find that the linear polarization of SN 2012bh at the early stage of the envelope expansion was less than 3%. Polarization measurements for the blazars OC 457, 3C 454.3, QSO B1215+303, 87GB 165943.2+395846 at single nights are presented. We infer the degree of the linear polarization and polarization angle. The blazars OC 457 and 3C 454.3 were observed during their periods of activity. The results show that MASTER is able to measure substantially polarized light; at the same time it is not suitable for determining weak polarization (less than 5%) of dim objects (fainter than 16$^m$). Polarimetric observations of the optical emission from gamma-ray bursts and supernovae are necessary to investigate the nature of these transient objects.Comment: 31 pages, 12 figures, 4 tables; Exposure times in Table 2 have been correcte

HIGLY STABLE NITROXIDE SPIN LABELS FOR BIOPHYSICAL RESEARCH

This work was supported by the RSF, project # 19-13-000235 and Ministry of Science and Higher Education of the Russian Federation (grant No. 14. W03.31.0034)

Gepner-like models and Landau-Ginzburg/sigma-model correspondence

The Gepner-like models of $k^{K}$-type is considered. When $k+2$ is multiple of $K$ the elliptic genus and the Euler characteristic is calculated. Using free-field representation we relate these models with $\sigma$-models on hypersurfaces in the total space of anticanonical bundle over the projective space $\mathbb{P}^{K-1}$

Течение и исходы острого коронарного синдрома в условиях новой коронавирусной инфекции COVID-19

Abstract We analyzed the clinical condition of patients with COVID-19 of varying severity, changes in instrumental and laboratory parameters, and assessed the impact of the severity of the course of a new coronavirus infection on the outcomes of acute coronary syndrome.AIM OF STUDY To study the mutual influence of acute coronary syndrome and the new coronavirus infection COVID-19 on the nature of the course and outcomes of the disease.Materia l and methods In March 21, 2020 – May 31, 2021, 3 625 patients were treated for COVID-19, including 131 patients with acute coronary syndrome due to COVID-19 disease. All patients underwent a number of studies: computed tomography of the chest, electrocardiography, echocardiography, monitoring of biomarkers of myocardial damage, diagnostic coronary angiography and, if necessary, intracoronary therapeutic intervention.Results Data on the distribution of patients with COVID-19 according to the presence or absence of ST segment elevation on the electrocardiogram and the degree of lung tissue damage, as well as information on mortality in these groups, are presented. The role of troponin I in the assessment of myocardial ischemia was analyzed. The direct dependence of its level on the volume of lung damage was found. The inverse relationship was shown between the degree of damage to the lung tissue and the indices of oxygen saturation in the blood. A poor prognostic value of low left ventricular ejection fraction in patients with COVID-19 disease has been described.Conclusions The development of acute coronary syndrome in the course of COVID-19 significantly worsens the prognosis of the disease, which requires the development of algorithms for providing medical care to patients in this category, as well as maximum vigilance in their treatment.ЦЕЛЬ ИССЛЕДОВАНИЯ Изучить взаимное влияние ОКС и НКИ COVID-19 на характер течения и исходы заболевания.МАТЕРИАЛ И МЕТОДЫ В ГБУЗ «НИИ СП им. Н.В. Склифосовского ДЗМ» с 21 марта 2020 по 31 мая 2021 года по поводу COVID-19 находились на лечении 3625 пациентов. В том числе по поводу ОКС на фоне заболевания COVID-19 госпитализирован 131 пациент. Всем больным был проведен ряд исследований: компьютерная томография органов грудной клетки, электрокардиография, эхокардиография, контроль биомаркеров повреждения миокарда, диагностическая коронароангиография и, при необходимости, интракоронарное лечебное вмешательство.РЕЗУЛЬТАТЫ Представлены данные о распределении больных COVID-19 по признаку наличия или отсутствия элевации сегмента ST на электрокардиограмме и степени поражения легочной ткани, а также сведения о летальности в данных группах. Проанализирована роль биомаркера тропонин I в оценке ишемии миокарда. Обнаружена прямая зависимость его уровня от объема повреждения легких. Показана обратная зависимость между степенью поражения легочной ткани и показателями сатурации кислорода в крови. Описано неблагоприятное прогностическое значение низкой фракции выброса левого желудочка у пациентов с заболеванием COVID-19.ЗАКЛЮЧЕНИЕ Развитие острого коронарного синдрома на фоне COVID-19 значительно ухудшает прогноз заболевания, что требует разработки алгоритмов оказания медицинской помощи больным этой категории, а также максимальной настороженности при их лечении

The MASTER-II network of robotic optical telescopes. First results

The main stages in the creation of the Russian segment of the MASTER network of robotic telescopes is described. This network is designed for studies of the prompt optical emission of gammaray bursts (GRBs; optical emission synchronous with the gamma-ray radiation) and surveys of the sky aimed at discovering uncataloged objects and photometric studies for various programs. The first results obtained by the network, during its construction and immediately after its completion in December 2010, are presented. Eighty-nine alert pointings at GRBs (in most cases, being the first ground telescopes to point at the GRBs) were made from September 2006 through July 2011. The MASTER network holds first place in the world in terms of the total number of first pointings, and currently more than half of first pointings at GRBs by ground telescopes are made by the MASTER network. Photometric light curves of GRB 091020, GRB 091127, GRB 100901A, GRB 100906A, GRB 10925A, GRB 110106A, GRB 110422A, and GRB 110530A are presented. It is especially important that prompt emission was observed for GRB 100901A and GRB 100906A, and thar GRB 091127, GRB 110422A, and GRB 110106A were observed from the first seconds in two polarizations. Very-wide-field cameras carried out synchronous observations of the prompt emission of GRB 081102, GRB 081130B, GRB 090305B, GRB 090320B, GRB 090328, and GRB 090424. Discoveries of Type Ia supernovae are ongoing (among them the brightest supernova in 2009): 2008gy, 2009nr, 2010V, and others. In all, photometry of 387 supernovae has been carried out, 43 of which were either discovered or first observed with MASTER telescopes; more than half of these are Type Ia supernovae. Photometric studies of the open clusters NGC 7129 and NGC 7142 have been conducted, leading to the discovery of 38 variable stars. Sixty-nine optical transients have been discovered. © 2013 Pleiades Publishing, Ltd