Effects of Neutral Hydrogen on Cosmic Ray Precursors in Supernova Remnant Shock Waves

Many fast supernova remnant shocks show spectra dominated by Balmer lines. The H$\alpha$ profiles have a narrow component explained by direct excitations and a thermally Doppler broadened component due to atoms that undergo charge exchange in the post-shock region. However, the standard model does not take into account the cosmic-ray shock precursor, which compresses and accelerates plasma ahead of the shock. In strong precursors with sufficiently high densities, the processes of charge exchange, excitation and ionization will affect the widths of both narrow and broad line components. Moreover, the difference in velocity between the neutrals and the precursor plasma gives rise to frictional heating due to charge exchange and ionization in the precursor. In extreme cases, all neutrals can be ionized by the precursor. In this paper we compute the ion and electron heating for a wide range of shock parameters, along with the velocity distribution of the neutrals that reach the shock. Our calculations predict very large narrow component widths for some shocks with efficient acceleration, along with changes in the broad- to-narrow intensity ratio used as a diagnostic for the electron-ion temperature ratio. Balmer lines may therefore provide a unique diagnostic of precursor properties. We show that heating by neutrals in the precursor can account for the observed H$\alpha$ narrow component widths, and that the acceleration efficiency is modest in most Balmer line shocks observed thus far.Comment: 9 pages, 3 figure

On the origin of tropospheric O₃ over the Indian Ocean during the winter monsoon: African biomass burning vs. stratosphere-troposphere exchange

This study investigates the origin of a commonly observed feature in the O₃ profiles: mid tropospheric O₃ maxima (300--500 hPa) over the tropical Indian Ocean. A comparison and analysis of model simulations, using a 3-D global climate-chemistry model, and measured O₃ profiles from the INDOEX campaign is presented. European Centre for Medium-Range Weather Forecast (ECMWF) meteorological analyses have been assimilated into the 3-D model to represent actual meteorology. The model realistically simulates the observed mid-tropospheric O₃ maxima. The analysis of the model simulations shows that the major source of the mid-tropospheric O₃maxima is advection of polluted air masses from continental biomass burning areas over Africa, with generally only a small contribution of stratospheric O₃. Previous studies hinted at stratosphere-troposphere exchange (STE) along the subtropical jet (STJ) as the primary source of the mid-tropospheric O₃ maxima over the Indian Ocean. Analysis of the model simulations shows that the mechanism causing the mid-tropospheric transport of African biomass burning pollution and stratospheric air masses are frontal zones or waves passing along the subtropical jets, causing advection of tropical air masses in the prefrontal (equatorward) zone. Furthermore, the frontal zones or waves also cause STE at the poleward side of the STJ. The model simulations also indicate that the contribution of STE in general is minor compared to advection and in situ tropospheric production of O₃ for the mid-tropospheric O₃ budget over the Indian Ocean region

Оппозиция концептов жизнь-смерть в смысловой организации петербургского текста русской культуры

Цель исследования – рассмотрение ведущей для организации Петербургского текста оппозиции концептов жизнь-смерть, члены которой получают репрезентацию в составляющих единство текстах А.С. Пушкина, Н.В. Гоголя, Ф.М. Достоевского, А.А. Блока, А.А. Ахматовой, О.Э. Мандельштама, Т.Н. Толстой и др. и участвуют в создании их общего смыслового пространства. Данные концепты оказываются ключевыми для понимания сверхтекста, герои которого вынуждены выбирать между смертью и жизнью, полной страданий.The article is devoted to the opposition of concepts life-death that plays the main part in Petersburg text’s organization. These concepts appear in texts written by A.S. Pushkin, N.V. Gogol, P.M. Dostoevsky, A.A. Blok, A.A. Ahmatova, O.E. Mandelshtam, T.N. Tolstaya etc. and help to unite their semantic space. The analysis of concepts life-death is necessary to understand the super-text which main characters have to choose between death and hard life

A risk-level assessment system based on the STRIDE/DREAD model for digital data marketplaces

Security is a top concern in digital infrastructure and there is a basic need to assess the level of security ensured for any given application. To accommodate this requirement, we propose a new risk assessment system. Our system identifies threats of an application workflow, computes the severity weights with the modified Microsoft STRIDE/DREAD model and estimates the final risk exposure after applying security countermeasures in the available digital infrastructures. This allows potential customers to rank these infrastructures in terms of security for their own specific use cases. We additionally present a method to validate the stability and resolution of our ranking system with respect to subjective choices of the DREAD model threat rating parameters. Our results show that our system is stable against unavoidable subjective choices of the DREAD model parameters for a specific use case, with a rank correlation higher than 0.93 and normalised mean square error lower than 0.05

Low antithrombin levels are associated with low risk of cardiovascular death but are a risk factor for cancer mortality

Background: Thrombosis is common in subjects suffering from cardiovascular diseases (CVD) and cancer. Hypercoagulation plays a pivotal role in the pathophysiology of thrombosis. Therefore, the inactivation of thrombin, the key enzyme in coagulation, is tightly regulated via antithrombin (AT). AT deficiency is related to thrombosis and cardiovascular death. In this study we investigated the association between AT levels and mortality, in particularly cardiovascular- related and cancer-related death in the general population. Methods: We studied the association of AT levels and mortality in a prospective cohort sampled from the general Italian population (n = 19,676). AT levels were measured in the baseline samples, and mortality was recorded during a median follow-up period of 8.2 years. Cox regression was performed to investigate the association of all-cause, CVD-related and cancerrelated mortality with variations in AT levels. Results: In total, 989 subjects died during follow-up, of which 373 subjects of CVD and 353 of cancerrelated causes. Cox analysis revealed that, after adjustment for age, sex, current smoking, BMI, diabetes, hypertension, hypercholesterolemia, history of cardiovascular disease, history of cancer, vitamin K antagonists, antiplatelet medication, heparin and oral contraceptives AT levels were not associated with all-cause mortality (HRQ1vsQ5: 0.92, 95% CI:0.74- 1.15). Interestingly, the risk of CVD-related mortality was reduced in subjects with low AT levels compared to subjects with higher AT levels, after adjustment for age and sex and other confounders did not change the association (HRQ1vsQ5: 0.64, 95% CI:0.44-0.91). Moreover, low AT levels were associated with increased cancer mortality in a fully adjusted model (HRQ1vsQ2-5: 1.26, 95% CI:0.88-1.81). Conclusions: Low AT levels are associated to a lower risk of fatal cardiovascular events in the general population, regardless of age, sex and medication use. In contrast, low AT levels are associated with lower cancer survival. For the first time we show that AT levels lower than the normal range in the general population, even before the development or diagnosis of cancer, are associated with an elevated risk of cancer death