486 research outputs found

    SpECTRE: A Task-based Discontinuous Galerkin Code for Relativistic Astrophysics

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    We introduce a new relativistic astrophysics code, SpECTRE, that combines a discontinuous Galerkin method with a task-based parallelism model. SpECTRE's goal is to achieve more accurate solutions for challenging relativistic astrophysics problems such as core-collapse supernovae and binary neutron star mergers. The robustness of the discontinuous Galerkin method allows for the use of high-resolution shock capturing methods in regions where (relativistic) shocks are found, while exploiting high-order accuracy in smooth regions. A task-based parallelism model allows efficient use of the largest supercomputers for problems with a heterogeneous workload over disparate spatial and temporal scales. We argue that the locality and algorithmic structure of discontinuous Galerkin methods will exhibit good scalability within a task-based parallelism framework. We demonstrate the code on a wide variety of challenging benchmark problems in (non)-relativistic (magneto)-hydrodynamics. We demonstrate the code's scalability including its strong scaling on the NCSA Blue Waters supercomputer up to the machine's full capacity of 22,380 nodes using 671,400 threads.Comment: 41 pages, 13 figures, and 7 tables. Ancillary data contains simulation input file

    The value of health

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    <p>Abstract</p> <p>Background</p> <p>A major problem in cost-effectiveness studies is where to draw the line between interventions which are cost-effective and those who are not. Lacking a notion about the value of a QALY, all ultimate values to the cost-effectiveness ratio are essentially arbitrary.</p> <p>Methods</p> <p>This paper presents a simple empirical model to estimate the compensating income variation of diseases and health problems. The model is estimated using data for the Netherlands.</p> <p>Results</p> <p>The compensating income variation is between €20,000 and €90,000. This is higher than most of the ultimate values used by policy-makers to decide whether an intervention is cost-effective. Our figures are roughly similar to those found in studies about the value of a statistical life year.</p> <p>Conclusion</p> <p>Estimates on the compensating income variation of diseases and health problems may provide useful information on the maximum acceptable cost-effectiveness ratio of medical interventions than those currently used by policy makers.</p

    Numerical Relativity: A review

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    Computer simulations are enabling researchers to investigate systems which are extremely difficult to handle analytically. In the particular case of General Relativity, numerical models have proved extremely valuable for investigations of strong field scenarios and been crucial to reveal unexpected phenomena. Considerable efforts are being spent to simulate astrophysically relevant simulations, understand different aspects of the theory and even provide insights in the search for a quantum theory of gravity. In the present article I review the present status of the field of Numerical Relativity, describe the techniques most commonly used and discuss open problems and (some) future prospects.Comment: 2 References added; 1 corrected. 67 pages. To appear in Classical and Quantum Gravity. (uses iopart.cls

    The Happiest Kids on Earth : Gender Equality and Adolescent Life Satisfaction in Europe and North America

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    Cross-national differences in adolescent life satisfaction in Europe and North America are consistent, but remain poorly understood. While previous studies have predominantly focused on the explanatory role of economic factors, such as national wealth and income equality, they revealed weak associations, at most. This study examines whether societal gender equality can explain the observed cross-national variability in adolescent life satisfaction. Based on the assumption that gender equality fosters a supportive social context, for example within families through a more equal involvement of fathers and mothers in child care tasks, adolescent life satisfaction was expected to be higher in more gender-equal countries. To test this hypothesis, national-level data of gender equality (i.e., women’s share in political participation, decision making power, economic participation and command over resources) were linked to data from 175,470 adolescents aged 11–16 years old (Mage = 13.6, SD = 1.64, 52% girls) from 34 European and North American countries involved in the 2009/10 Health Behaviour in School-aged Children (HBSC) study. Results of linear multilevel regression analyses indicate that adolescents in countries with relatively high levels of gender equality report higher life satisfaction than their peers in countries with lower levels of gender equality. The association between gender equality and adolescent life satisfaction remained significant after controlling for national wealth and income equality. It was equally strong for boys and girls. Moreover, the association between gender equality and life satisfaction was explained by social support in the family, peer and school context. This analysis suggests that gender equality fosters social support among members of a society, which in turn contributes to adolescent life satisfaction. Thus, promoting gender equality is likely to benefit all members of a society; not just by giving equal rights to women and girls, but also by fostering a supportive social climate for all

    The use of social services by community-dwelling older persons who are at risk of institutionalization: a survey

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    The use of community-based social services additionally to regular home help services to support older persons at risk of institutionalization was studied. Structured interviews were held with 292 persons, who specifically pointed out that they prefer to remain independently at home. Bivariate and multivariate logistic regression models were developed to study the association between social service use and personal, health-related and wellbeing characteristics. 195 respondents indicated that they made use of at least one social service (68%). Only three services (individual care, social-cultural activities and restaurant facilities), out of nine, were used regularly. Those who lived in a sheltered environment or were supported by informal caregivers or who visited day care had a significantly higher probability of using these services. More attention should be given to the nature and accessibility of community-based social services in order to have distinctive added value in enabling older persons to age in place

    Are Happiness and Life Satisfaction Different Across Religious groups? Exploring Determinants of Happiness and Life Satisfaction

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    This study explores whether different religions experience different levels of happiness and life satisfaction and in case this is affected by country economic and cultural environment. Using World Value Survey (from 1981 to 2014), this study found that individual religiosity and country level of development play a significant role in shaping people’s subjective well-being (SWB). Protestants, Buddhists and Roman Catholic were happier and most satisfied with their lives compared to other religious groups. Orthodox has the lowest SWB. Health status, household’s financial satisfaction and freedom of choice are means by which religious groups and governments across the globe can improve the SWB of their citizens. Keywords: happiness; life satisfaction; religion; religious differences; cultur

    The Warden Attitude: An investigation of the value of interaction with everyday wildlife

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    Using a discrete choice experiment, we elicit valuations of engagement with ‘everyday wildlife’ through feeding garden birds. We find that bird-feeding is primarily but not exclusively motivated by the direct consumption value of interaction with wildlife. The implicit valuations given to different species suggest that people prefer birds that have aesthetic appeal and that evoke human feelings of protectiveness. These findings suggest that people derive wellbeing by adopting a warden-like role towards ‘their’ wildlife. We test for external validity by conducting a hedonic analysis of sales of bird food. We discuss some policy implications of the existence of warden attitudes

    Happiness Through Vacationing: Just a Temporary Boost or Long-Term Benefits?

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    Does vacationing add to our happiness in the long run? This question was addressed in a study of 3,650 Dutch citizens who reported their leisure travel every 3 months during 2 years and rated their happiness at the end of each year. Participants who had been on vacation appeared to be marginally happier, in terms of hedonic level of affect, than those who had not. This difference in Affect balance between vacationers and non-vacationers is probably due to a very minor causal effect of vacationing on hedonic level of affect. Possibly, vacationing is positively reminisced and these memories allow for the prevalence of more positive affect in people's lives. Happiness did not predict vacationing. The effect of holiday trips on vacationers' happiness is mostly short-lived; among vacationers, happiness was unrelated to the number of trips and days spent on vacation. A separate analysis of vacationers, who value vacationing most, yielded the same results. Implications for future research are discussed
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