614 research outputs found

    SALINAS - An implicit finite element structural dynamics code developed for massively parallel platforms

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    As computational needs for structural finite element analysis increase, a robust implicit structural dynamics code is needed which can handle millions of degrees of freedom in the model and produce results with quick turn around time. A parallel code is needed to avoid limitations of serial platforms. Salinas is an implicit structural dynamics code specifically designed for massively parallel platforms. It computes the structural response of very large complex structures and provides solutions faster than any existing serial machine. This paper gives a current status of Salinas and uses demonstration problems to show Salinas' performance

    Carnot cycle for an oscillator

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    Carnot established in 1824 that the efficiency of cyclic engines operating between a hot bath at absolute temperature ThotT_{hot} and a bath at a lower temperature TcoldT_{cold} cannot exceed 1−Tcold/Thot1-T_{cold}/T_{hot}. We show that linear oscillators alternately in contact with hot and cold baths obey this principle in the quantum as well as in the classical regime. The expression of the work performed is derived from a simple prescription. Reversible and non-reversible cycles are illustrated. The paper begins with historical considerations and is essentially self-contained.Comment: 19 pages, 3 figures, sumitted to European Journal of Physics Changed content: Fluctuations are considere

    The Emerging Aversion to Inequality: Evidence from Poland 1992-2005

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    This paper provides an illustration of the changing tolerance for inequality in a context of radical political and economic transformation and rapid economic growth. We focus on the Polish experience of transition and explore self-declared attitudes of the citizens. Using monthly representative surveys of the population, realized by the Polish poll institute (CBOS) from 1992 to 2005, we identify a structural break in the relation between income inequality and subjective evaluation of well-being. The downturn in the tolerance for inequality (1997) coincides with the increasing distrust of political elites.http://deepblue.lib.umich.edu/bitstream/2027.42/64387/1/wp919.pd

    Severe Air Pollution and School Absences: Longitudinal Data on Expatriates in North China

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    Little is known about how children of high-income expatriate families, often from rich nations, adapt to temporary residence in a severely polluted city of the developing world. We use a six-year panel of 6,500 students at three international schools in a major city in north China to estimate how fluctuation in ambient PM2.5 over the preceding fortnight impacts daily absences. Our preferred estimates are based on the exclusion restriction that absences respond to atmospheric ventilation such as thermal inversions only through ventilation's effect on particle levels. A large and rare 100 to 200 μg/m3 shift in average PM2.5 in the prior week raises the incidence of absences by 1 percentage point, about one-quarter of the sample mean. We find stronger responses for US/Canada nationals than among Chinese nationals, and among students who generally miss school the most. Overall responses are mod-est compared to the effect on absences from more moderate in-sample variation in pollution estimated for the US using aggregate data. Using school absence patterns as a window into short-run health and behavior, our study suggests that high-income families find ways to adapt, likely by moving life indoors, even if temporary residence in north China comes at the expense of long-term health

    Does a short-term intervention promote mental and general health among young adults? – An evaluation of counselling

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    <p>Abstract</p> <p>Background</p> <p>Since 1988, self-reported mental health problems in Sweden have increased more among young people than in any other age group. Young adults aged 18 – 29 with minor mental health problems were welcomed to four (at most) counselling sessions led by psychotherapists. The present study aimed to evaluate the method's appropriateness and usefulness.</p> <p>Methods</p> <p>The study population was recruited consecutively during six months (N = 74) and consisted of 59 women and 15 men. Fifty-one, 46 women and five men, met the criterion for a <it>personal semi-structured interview </it>three months post intervention. Self-assessed health data were collected on three occasions using the General Health Questionnaire (GHQ-12), Pearlin's Personal Mastery Scale and two items from the Swedish Living Conditions Surveys. Thirteen women and six men were not statistically assessed due to incomplete data, but were <it>interviewed by telephone</it>. Four men refused to be interviewed and became <it>dropouts</it>.</p> <p>Results</p> <p>The largest group of the study population had long been troubled by their problem(s): 43 percent for over three years and 28 percent for over one year. Among those <it>personally interviewed</it>, 76 percent reported psychological distress (> 3 GHQ points) before the counselling. After the counselling, GHQ-12 distress decreased by 50 percent while mastery and perceived health status increased significantly. A majority experienced an improved life situation, found out something new about themselves and could make use of the sessions afterwards. Personal participant session contentment was about 70 percent and all counsellees would recommend the intervention to a friend. Those <it>interviewed by telephone </it>were not statistically assessed due to incomplete health data. Their personal contentment was just under 50 percent, though all except one would recommend the counselling to a friend. Their expectations of the intervention were more result-orientated compared to the more process-directed personally-interviewed group.</p> <p>Conclusion</p> <p>This evaluation shows a clear improvement in self-rated mental and general health, mastery and control in the group completing the study agreement. The intervention seems to be effective for young adults with minor mental health problems, but due to the skewed gender-distribution it is unclear if the method is appropriate for men. After the proposed internal quality improvements, this short-term counselling could enhance mental and general health among young people.</p

    Always Affecting the Wrong People? The Impact of US Sanctions on Poverty

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    In this paper, we analyze the effect of US economic sanctions on the target countries' poverty gap during the period 1978-2011. Econometrically, we employ a nearest neighbor matching approach to account for differences in the countries' economic and political environment and the likelihood of being exposed to US sanctions. Our results indicate that US sanctions are indeed affecting the wrong people as we observe a 2.3-5.1 percentage points (pp) larger poverty gap in sanctioned countries compared to their nearest neighbors. Severe sanctions, such as fuel embargoes, trade restrictions, the freezing of assets, or embargoes on most or all economic activity are particularly detrimental and lead to an increase in the poverty gap by 6.1-7.4 pp

    Differential Income Taxation and Household Asset Allocation

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    This paper empirically investigates the effects of differential income taxation on households' portfolio choice and asset allocation applying a two-stage budgeting model of asset demand to German survey data. The model is structured into the discrete asset choice and the continuous asset choice, and the marginal income tax rate is simulated in a module of income taxation. Households that face relatively higher tax rates are found to have relatively greater demand for tax-privileged assets than households in the lower tax brackets. The higher the marginal tax rate the greater demand is for non-owner-occupied housing, for mortgage repayments, for building society deposits, for stocks, for insurances, and for consumer credits, whereas demand is lower for owner-occupied housing, bank deposits, and bonds
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