345 research outputs found

    Modified Boltzmann Transport Equation and Freeze Out

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    We study Freeze Out process in high energy heavy ion reaction. The description of the process is based on the Boltzmann Transport Equation (BTE). We point out the basic limitations of the BTE approach and introduce Modified BTE. The Freeze Out dynamics is presented in the 4-dimensional space-time in a layer of finite thickness, and we employ Modified BTE for the realistic Freeze Out description.Comment: 9 pages, 2 figure

    The 3rd Flow Component as a QGP Signal

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    Earlier fluid dynamical calculations with QGP show a softening of the directed flow while with hadronic matter this effect is absent. On the other hand, we indicated that a third flow component shows up in the reaction plane as an enhanced emission, which is orthogonal to the directed flow. This is not shadowed by the deflected projectile and target, and shows up at measurable rapidities, ycm=12y_cm = 1-2. To study the formation of this effect initial stages of relativistic heavy ion collisions are studied. An effective string rope model is presented for heavy ion collisions at RHIC energies. Our model takes into account baryon recoil for both target and projectile, arising from the acceleration of partons in an effective field. The typical field strength (string tension) for RHIC energies is about 5-12 GeV/fm, what allows us to talk about "string ropes". The results show that QGP forms a tilted disk, such that the direction of the largest pressure gradient stays in the reaction plane, but deviates from both the beam and the usual transverse flow directions. The produced initial state can be used as an initial condition for further hydrodynamical calculations. Such initial conditions lead to the creation of third flow component. Recent v1v_1 measurements are promising that this effect can be used as a diagnostic tool of the QGP

    Anthropometric trends and the risk of cardiovascular disease mortality in a Lithuanian urban population aged 45-64 years

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    To estimate trends in anthropometric indexes from 1992 to 2008 and to evaluate the risk of cardiovascular disease mortality in relation to anthropometric indexes (body mass index, waist circumference, waist:hip ratio, waist:height ratio)

    SCORE performance in Central and Eastern Europe and former Soviet Union: MONICA and HAPIEE results

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    Aims: The Systematic COronary Risk Evaluation (SCORE) scale assesses 10 year risk of fatal atherosclerotic cardiovascular disease (CVD), based on conventional risk factors. The high-risk SCORE version is recommended for Central and Eastern Europe and former Soviet Union (CEE/FSU), but its performance has never been systematically assessed in the region. We evaluated SCORE performance in two sets of population-based CEE/FSU cohorts. Methods and results: The cohorts based on the World Health Organization MONitoring of trends and determinants in CArdiovascular disease (MONICA) surveys in the Czech Republic, Poland (Warsaw and Tarnobrzeg), Lithuania (Kaunas), and Russia (Novosibirsk) were followed from the mid-1980s. The Health, Alcohol, and Psychosocial factors in Eastern Europe (HAPIEE) study follows Czech, Polish (Krakow), and Russian (Novosibirsk) cohorts from 2002–05. In Cox regression analyses, the high-risk SCORE ≥5% at baseline significantly predicted CVD mortality in both MONICA [n = 15 027; hazard ratios (HR), 1.7–6.3] and HAPIEE (n = 20 517; HR, 2.6–10.5) samples. While SCORE calibration was good in most MONICA samples (predicted and observed mortality were close), the risk was underestimated in Russia. In HAPIEE, the high-risk SCORE overpredicted the estimated 10 year mortality for Czech and Polish samples and adequately predicted it for Russia. SCORE discrimination was satisfactory in both MONICA and HAPIEE. Conclusion: The high-risk SCORE underestimated the fatal CVD risk in Russian MONICA but performed well in most MONICA samples and Russian HAPIEE. This SCORE version might overestimate the risk in contemporary Czech and Polish populations

    Link between healthy lifestyle and psychological well-being in Lithuanian adults aged 45-72: a cross-sectional study

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    OBJECTIVE: This study uses a cross-sectional study design to analyse the connection between psychological well-being (PWB) and components of a healthy lifestyle in the Lithuanian population aged 45–72. The purpose of our study is to establish the links between PWB and lifestyle factors such as physical activity, smoking, alcohol consumption and dietary patterns in people above the age of 44. PARTICIPANTS: A stratified sample of 10 940 urban citizens aged 45–72 years were randomly selected from the National Population Register. The response rate was 65%. METHODS: PWB was evaluated by using a Control Autonomy Self-realization and Pleasure (CASP-12) questionnaire. The standard questionnaire included questions regarding the respondent's sociodemographic, socioeconomic and social status. The lifestyle questionnaire evaluated behavioural factors as smoking status, alcohol consumption, nutrition habits and physical activity. Objective measurements of cardiovascular disease (CVD) risk factors were taken. RESULTS: Adjusted for sociodemographic, socioeconomic, social and biological CVD risk factors, the probability of higher PWB increased for physically active men and women and male former smokers. Higher PWB was directly associated with consumption of fresh vegetables and fruits. Responders who consumed potatoes, meat, boiled vegetables and eggs less frequently than average were more likely to have higher PWB. A direct association was ascertained between PWB and consumption of chicken and fish, as well as an inverse association between PWB and consumption of sweets in women. CONCLUSIONS: Healthy lifestyle education efforts should focus on increasing physical activity, controlling smoking and improving diversity in healthy food consumption including the consumption of fresh vegetables and fruits, particularly among older adults with lower PWB

    Correlates of depressive symptoms in urban middle-aged and elderly Lithuanians.

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    The study aimed to examine the prevalence of depressive symptoms and their correlates in urban middle-aged and elderly Lithuanian adults

    Covariant description of kinetic freeze out through a finite time-like layer

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    The Freeze Out (FO) problem is addressed for a covariant FO probability and a finite FO layer with a time-like normal vector continuing the line of studies introduced in Ref. [1]. The resulting post FO momentum distribution functions are presented and discussed. We show that in general the post FO distributions are non-thermal and asymmetric distributions even for time-like FO situations.Comment: 10 pages, 12 figures, major rewrite with changed content, corrected typos and new references adde

    Covariant description of kinetic freeze out through a finite space-like layer

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    The problem of Freeze Out (FO) in relativistic heavy ion reactions is addressed. We develop and analyze an idealized one-dimensional model of FO in a finite layer, based on the covariant FO probability. The resulting post FO phase-space distributions are discussed for different FO probabilities and layer thicknesses.Comment: 16 pages, 19 figures, changed content, references adde
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