Laws of distribution of the snow cover on the greater Caucasus (Soviet Union)

The laws of the distribution of the snow cover on the mountains of the greater Caucasus are discussed. It is shown that an extremely unequal distribution of the snow cover is caused by the complex orography of this territory, the diversity of climatic conditions and by the difference in altitude. Regions of constant, variable and unstable snow cover are distinguished because of the clearly marked division into altitude layers, each of which is characterized by climatic differences in the nature of the snow accumulation

THE EFFECT OF THE THERMOHYDROGEN TREATMENT ON THE CAST STRUCTURE TRANSFORMATION AND THE MECHANICAL PROPERTIES IN THE TITANIUM ALLOY

В данной работе изучено влияние обратимого легирования водородом на преобразование структуры ножки эндопротеза тазобедренного сустава, полученной фасонным литьем из титанового сплава ВТ6. Разработан оптимальный режим термоводородной обработки, позволяющий сформировать структуру с комплексом механических свойств, отвечающих международным стандартам.In this work, the effect of the reversible hydrogen alloying on the structure transformation and mechanical properties of the hip implant stem produced by the shaped casting of the titanium alloy VT6 was investigated. The most preferable thermohydrogen treatment condition that enables to achieve the structure and mechanical properties complied with the international standards was developed.Работа выполнена в рамках Государственного задания высшим учебным заведениям в части проведения НИР № 2895.14

Particulate organic carbon and nitrogen export from major Arctic rivers

Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 30 (2016): 629–643, doi:10.1002/2015GB005351.Northern rivers connect a land area of approximately 20.5 million km2 to the Arctic Ocean and surrounding seas. These rivers account for ~10% of global river discharge and transport massive quantities of dissolved and particulate materials that reflect watershed sources and impact biogeochemical cycling in the ocean. In this paper, multiyear data sets from a coordinated sampling program are used to characterize particulate organic carbon (POC) and particulate nitrogen (PN) export from the six largest rivers within the pan-Arctic watershed (Yenisey, Lena, Ob', Mackenzie, Yukon, Kolyma). Together, these rivers export an average of 3055 × 109 g of POC and 368 × 109 g of PN each year. Scaled up to the pan-Arctic watershed as a whole, fluvial export estimates increase to 5767 × 109 g and 695 × 109 g of POC and PN per year, respectively. POC export is substantially lower than dissolved organic carbon export by these rivers, whereas PN export is roughly equal to dissolved nitrogen export. Seasonal patterns in concentrations and source/composition indicators (C:N, δ13C, Δ14C, δ15N) are broadly similar among rivers, but distinct regional differences are also evident. For example, average radiocarbon ages of POC range from ~2000 (Ob') to ~5500 (Mackenzie) years before present. Rapid changes within the Arctic system as a consequence of global warming make it challenging to establish a contemporary baseline of fluvial export, but the results presented in this paper capture variability and quantify average conditions for nearly a decade at the beginning of the 21st century.National Science Foundation Grant Numbers: 0229302, 0732985; U.S. Geological Survey; Department of Indian and Northern Affairs2016-11-1

Seasonal and annual fluxes of nutrients and organic matter from large rivers to the Arctic Ocean and surrounding seas

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 35 (2012): 369-382, doi:10.1007/s12237-011-9386-6.River inputs of nutrients and organic matter impact the biogeochemistry of arctic estuaries and the Arctic Ocean as a whole, yet there is considerable uncertainty about the magnitude of fluvial fluxes at the pan-arctic scale. Samples from the six largest arctic rivers, with a combined watershed area of 11.3 x 106 km2, have revealed strong seasonal variations in constituent concentrations and fluxes within rivers as well as large differences among the rivers. Specifically, we investigate fluxes of dissolved organic carbon, dissolved organic nitrogen, total dissolved phosphorus, dissolved inorganic nitrogen, nitrate, and silica. This is the first time that seasonal and annual constituent fluxes have been determined using consistent sampling and analytical methods at the pan arctic scale, and consequently provide the best available estimates for constituent flux from land to the Arctic Ocean and surrounding seas. Given the large inputs of river water to the relatively small Arctic Ocean, and the dramatic impacts that climate change is having in the Arctic, it is particularly urgent that we establish the contemporary river fluxes so that we will be able to detect future changes and evaluate the impact of the changes on the biogeochemistry of the receiving coastal and ocean systems.This work was supported by the National Science Foundation through grants OPP-0229302, OPP-0519840, OPP-0732522, and OPP-0732944. Additional support was provided by the U. S. Geological Survey (Yukon River) and the Department of Indian and Northern Affairs (Mackenzie River)

Electrocardiographic signs of the left main coronary artery disease in acute coronary syndrome

Myocardial infarction (MI) due to the left main coronary artery (LMCA) disease is a life-threatening condition. Evaluation of ECG signs of LMCA occlusion is important because of revascularization emergency. There is no single ECG pattern for LMCA occlusion. The purpose of the present literature review is to reveal ECG potential in diagnosing LMCA occlusion in acute coronary syndrome. Variability of ECG abnormalities was noted depending on the degree of LMCA occlusion, collateral blood flow from the right coronary artery, and concomitant stenosis. ST elevation in aVR is an evident predictor of LMCA lesion. Electrophysiological mechanisms of its formation were described. Diagnostic significance of additional ECG signs of LMCA disease was presented. Diagnostic and treatment strategies for patients with ECG signs of severe LMCA disease were summarized

CARDIAC LESION IN CHURG - STRAUSS SYNDROME

Cardiac involvement is the most important prognostic factor in eosinophilic granulomatosis with polyangiitis (Churg - Strauss syndrome). We report a case of Churg - Strauss syndrome in 65-year-old women masquerading as a non-ST elevation myocardial infarction. She had chest discomfort, dyspnea and ST depression, high troponin level and so myocardial infarction was diagnosed. She had had asthma for 4 years but had no eosinophilia in peripheral blood and lesions in the lungs at the time of the first hospitalization. Her skin was clean without rashes. 3 months later she was hospitalized again having pulmonary infiltrates. Laboratory tests revealed that eosinophil was significantly increased. Cardiac involvement in a pathological process led to death. Histological examination of heart and lungs showed necrotic coronary vasculitis, granulomas and perivascular eosinophilic infiltrates in myocardium, endocardium, pericardium and pulmonary eosinophilic infiltrates

Increasing Alkalinity Export from Large Russian Arctic Rivers

Riverine carbonate alkalinity (HCO₃^– and CO₃^2–) sourced from chemical weathering represents a significant sink for atmospheric CO₂. Alkalinity flux from Arctic rivers is partly determined by precipitation, permafrost extent, groundwater flow paths, and surface vegetation, all of which are changing under a warming climate. Here we show that over the past three and half decades, the export of alkalinity from the Yenisei and Ob’ Rivers increased from 225 to 642 Geq yr^–1 (+185%) and from 201 to 470 Geq yr^–1 (+134%); an average rate of 11.90 and 7.28 Geq yr^–1, respectively. These increases may have resulted from a suite of changes related to climate change and anthropogenic activity, including higher temperatures, increased precipitation, permafrost thaw, changes to hydrologic flow paths, shifts in vegetation, and decreased acid deposition. Regardless of the direct causes, these trends have broad implications for the rate of carbon sequestration on land and delivery of buffering capacity to freshwater ecosystems and the Arctic Ocean

Increasing Alkalinity Export from Large Russian Arctic Rivers

Riverine carbonate alkalinity (HCO₃^– and CO₃^2–) sourced from chemical weathering represents a significant sink for atmospheric CO₂. Alkalinity flux from Arctic rivers is partly determined by precipitation, permafrost extent, groundwater flow paths, and surface vegetation, all of which are changing under a warming climate. Here we show that over the past three and half decades, the export of alkalinity from the Yenisei and Ob’ Rivers increased from 225 to 642 Geq yr^–1 (+185%) and from 201 to 470 Geq yr^–1 (+134%); an average rate of 11.90 and 7.28 Geq yr^–1, respectively. These increases may have resulted from a suite of changes related to climate change and anthropogenic activity, including higher temperatures, increased precipitation, permafrost thaw, changes to hydrologic flow paths, shifts in vegetation, and decreased acid deposition. Regardless of the direct causes, these trends have broad implications for the rate of carbon sequestration on land and delivery of buffering capacity to freshwater ecosystems and the Arctic Ocean