3,198 research outputs found

    Structure and diffusion processes in laminated composites of a Cu-Ti system

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    Characteristics of diffusion transformations in a multi-layer composite of a Cu-Ti system, which was produced by high-temperature diffusion welding followed by rolling at room temperature, are reportedye

    Predictive value of cardiovascular risk factors in the formation of cardiovascular and all-cause mortality: results of a 27-year cohort prospective study

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    Aim. To study the prognostic significance of cardiovascular risk factors (RFs) in the formation of all-cause and cardiovascular mortality based on the results of a 27-year prospective cohort study of Tomsk population of both sexes aged 20-59 years.Material and methods. The object of study was random house-to-house sample of Tomsk population. In total, 1546 people (630 men and 916 women) aged 20-59 were examined. In 1988-1991, the prevalence of following cardiovascular RFs was studied: hypertension (HTN), overweight, smoking, alcohol consumption, hypercholesterolemia (HCE), low high-density lipoprotein cholesterol levels (hypo-HDL-emia), hypertriglyceridemia (HTG). All examination methods used were strictly standardized. To determine the RF, the criteria generally accepted in epidemiological studies were used. Over 27 years of follow-up, 330 deaths were recorded, including 142 due to cardiovascular disease.Results. In the multivariate Cox proportional hazard model, the following va­riables were studied: HTN, overweight, smoking, alcohol consumption, HCE, hypo-HDL-emia, HTG, coronary artery disease (CAD) (according to epi­demio­logical criteria), and age. The strongest predictor of of all-cause death was frequent alcohol use (relative risk (RR) 2,75). Smoking increased the risk of death by 2,72 times. Among former smokers, the risk of all-cause death was 1,9 times higher compared to non-smokers. HTN increases the death risk by 1,61 times. Each year of life lived increases the death risk by 1,06 times. The most significant risk factor for death from CVD was frequent alcohol consumption (RR 3,01). Smoking increases the cardiovascular death risk by 2,28 times. Among former smokers, the RR of cardiovascular death was 1,91. HTN increases the risk of cardiovascular mortality by 1,84 times compared with people with normal blood pressure. Each year of life lived increases the risk of cardiovascular death by 1,1 times. In multivariate analysis, overweight, HCE, hypo-HDL-emia, HTG did not have a significant independent effect on the all-cause and cardiovascular death risk.Conclusion. In a 27-year cohort prospective study, independent predictors of all-cause and cardiovascular mortality, along with hypertension and age, were lifestyle risk factors, such as smoking and frequent alcohol consumption

    Future of superheavy element research: Which nuclei could be synthesized within the next few years?

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    Low values of the fusion cross sections and very short half-lives of nuclei with Z>>120 put obstacles in synthesis of new elements. Different nuclear reactions (fusion of stable and radioactive nuclei, multi-nucleon transfers and neutron capture), which could be used for the production of new isotopes of superheavy (SH) elements, are discussed in the paper. The gap of unknown SH nuclei, located between the isotopes which were produced earlier in the cold and hot fusion reactions, can be filled in fusion reactions of 48^{48}Ca with available lighter isotopes of Pu, Am, and Cm. Cross sections for the production of these nuclei are predicted to be rather large, and the corresponding experiments can be easily performed at existing facilities. For the first time, a narrow pathway is found to the middle of the island of stability owing to possible β+\beta^+-decay of SH isotopes which can be formed in ordinary fusion reactions of stable nuclei. Multi-nucleon transfer processes at near barrier collisions of heavy (and very heavy, U-like) ions are shown to be quite realistic reaction mechanism allowing us to produce new neutron enriched heavy nuclei located in the unexplored upper part of the nuclear map. Neutron capture reactions can be also used for the production of the long-living neutron rich SH nuclei. Strong neutron fluxes might be provided by pulsed nuclear reactors and by nuclear explosions in laboratory conditions and by supernova explosions in nature. All these possibilities are discussed in the paper.Comment: An Invited Plenary Talk given by Valeriy I. Zagrebaev at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

    Low temperature breakdown of coherent tunneling in amorphous solids induced by the nuclear quadrupole interaction

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    We consider the effect of the internal nuclear quadrupole interaction on quantum tunneling in complex multi-atomic two-level systems. Two distinct regimes of strong and weak interactions are found. The regimes depend on the relationship between a characteristic energy of the nuclear quadrupole interaction λ\lambda_{\ast} and a bare tunneling coupling strength Δ0\Delta_{0}. When Δ0>λ\Delta_{0}>\lambda_{\ast}, the internal interaction is negligible and tunneling remains coherent determined by Δ0\Delta_{0}. When Δ0<λ\Delta_{0}<\lambda_{\ast}, coherent tunneling breaks down and an effective tunneling amplitude decreases by an exponentially small overlap factor η1\eta^{\ast}\ll1 between internal ground states of left and right wells of a tunneling system. This affects thermal and kinetic properties of tunneling systems at low temperatures T<λT<\lambda_{*}. The theory is applied for interpreting the anomalous behavior of the resonant dielectric susceptibility in amorphous solids at low temperatures T5T\leq 5mK where the nuclear quadrupole interaction breaks down coherent tunneling. We suggest the experiments with external magnetic fields to test our predictions and to clarify the internal structure of tunneling systems in amorphous solids.Comment: To appear in the Physical Review

    Exceptional Collections and del Pezzo Gauge Theories

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    Stacks of D3-branes placed at the tip of a cone over a del Pezzo surface provide a way of geometrically engineering a small but rich class of gauge/gravity dualities. We develop tools for understanding the resulting quiver gauge theories using exceptional collections. We prove two important results for a general quiver gauge theory: 1) we show the ordering of the nodes can be determined up to cyclic permutation and 2) we derive a simple formula for the ranks of the gauge groups (at the conformal point) in terms of the numbers of bifundamentals. We also provide a detailed analysis of four node quivers, examining when precisely mutations of the exceptional collection are related to Seiberg duality.Comment: 26 pages, 1 figure; v2 footnote 2 amended; v3 ref adde

    Measurement of J/ψγηcJ/\psi\to\gamma\eta_{\rm c} decay rate and ηc\eta_{\rm c} parameters at KEDR

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    Using the inclusive photon spectrum based on a data sample collected at the J/ψJ/\psi peak with the KEDR detector at the VEPP-4M e+ee^+e^- collider, we measured the rate of the radiative decay J/ψγηcJ/\psi\to\gamma\eta_{\rm c} as well as ηc\eta_{\rm c} mass and width. Taking into account an asymmetric photon lineshape we obtained Γγηc0=2.98±0.180.33+0.15\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18 \phantom{|}^{+0.15}_{-0.33} keV, Mηc=2983.5±1.43.6+1.6M_{\eta_{\rm c}} = 2983.5 \pm 1.4 \phantom{|}^{+1.6}_{-3.6} MeV/c2c^2, Γηc=27.2±3.12.6+5.4\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1 \phantom{|}^{+5.4}_{-2.6} MeV.Comment: 6 pages, 3 figure

    Ways to increase adherence to antihypertensive therapy

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    With a high prevalence in the Russian population and insufficient effectiveness of treatment, hypertension remains a poorly controlled cardiovascular risk factor, including due to the low compliance of patients. Noncompliance is due to a large number of factors, some of which were studied in post-hoc analysis of the Russian observational STIL’ and TRICOLOR studies. It demonstrated that fixed-dose combinations of antihypertensive drugs can make a significant contribution to solving such a complex problem as low compliance

    Spousal body weight concordance and the impact of spouse overweight on death risk: data form a 27-year cohort prospective study

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    Aim. To study the interdependence of spousal body mass and influence of spouse overweight on the death risk according to the 27-year cohort prospective study.Material and methods. We examined a random household sample (n=1546; married couples, 427). Overweight frequency among spouses was studied on the first stage of the study (1988-1991). In 2002-2005 (stage II), the examination was repeated and overweight dynamics were studied. In 2015 (stage III), we analyze mortality rates and significance of overweight and spousal overweight for the mortality risk formation. Overweight was detected in people with body mass index ≥25 kg/m2. Two hundred deaths were recorded during 27-year follow-up. Vital status was established for 97% of observed persons.Results. Overweight was detected in 61,1% of men who lived with overweight wife and in 45% of men whose wife had normal body mass (p&lt;0,01). Overweight was diagnosed more often in women whose husband also had overweight comparing with women who lived with normal weight husband (76,2% vs 61,7%; p&lt;0,001). The risk of overweight formation among individuals whose spouse’s body mass increased from norm to overweight was in 3,04 times higher than in persons whose spouse had a stable normal body mass and in 2,2 times higher than in participants whose spouse had overweight on study stages I and II. Relative risk of mortality in men who lived with overweight wife was 2,07.Conclusion. 1) We found the body mass concordance in spouses. 2) The average body mass index in men and women who lived with overweight spouse is higher than in men and women whose spouse had a normal body mass. 3) Interdependence of spousal body mass was revealed in dynamics. 4) Spousal overweight is an independent predictor of premature mortality in men
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