1,457 research outputs found

    A conservative approach to parallelizing the Sharks World simulation

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    Parallelizing a benchmark problem for parallel simulation, the Sharks World, is described. The described solution is conservative, in the sense that no state information is saved, and no 'rollbacks' occur. The used approach illustrates both the principal advantage and principal disadvantage of conservative parallel simulation. The advantage is that by exploiting lookahead an approach was found that dramatically improves the serial execution time, and also achieves excellent speedups. The disadvantage is that if the model rules are changed in such a way that the lookahead is destroyed, it is difficult to modify the solution to accommodate the changes

    Rock, Rap, or Reggaeton?: Assessing Mexican Immigrants' Cultural Assimilation Using Facebook Data

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    The degree to which Mexican immigrants in the U.S. are assimilating culturally has been widely debated. To examine this question, we focus on musical taste, a key symbolic resource that signals the social positions of individuals. We adapt an assimilation metric from earlier work to analyze self-reported musical interests among immigrants in Facebook. We use the relative levels of interest in musical genres, where a similarity to the host population in musical preferences is treated as evidence of cultural assimilation. Contrary to skeptics of Mexican assimilation, we find significant cultural convergence even among first-generation immigrants, which problematizes their use as assimilative "benchmarks" in the literature. Further, 2nd generation Mexican Americans show high cultural convergence vis-\`a-vis both Anglos and African-Americans, with the exception of those who speak Spanish. Rather than conforming to a single assimilation path, our findings reveal how Mexican immigrants defy simple unilinear theoretical expectations and illuminate their uniquely heterogeneous character.Comment: WebConf 201

    Spousal and parental roles among female student populations in 55 low-and middle-income countries

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    This paper exploits a vast database of international census and survey microdata to examine the relationship between school enrolment on the one hand and the status of being in a union or a parent on the other among female adolescents and young adults in low-and middle-income countries. Our analysis is based on widespread evidence for 55 countries among 15 to 24 year-old females. High shares of student population are strongly correlated with low shares in spousal and parental roles between countries. We show that this relationship is driven by the fact that students are less likely to be in spousal and parental roles compared to non-students. Nevertheless, as we compare older ages, the share of students reported as spouses and/or mothers increases. The prevalence of spousal and parental roles among the student population is correlated to the overall levels of spouses and mothers in the total population, even when controlling for the level of school currently attained

    Time-to-death patterns in markers of age and dependency

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    Altres ajuts: HHS/R01-AG011552Altres ajuts: HHS/R01-AG04024Altres ajuts: UK/ESRC/ES/K004611/1We aim to determine the extent to which variables commonly used to describe health, wellbeing, and disability in old-age vary primarily as a function of years lived (chronological age), years left (thanatological age), or as a function of both. We analyze data from the US Health and Retirement Study to estimate chronological age and time-to-death patterns in 78 such variables. We describe results from the birth cohort born 1915-1919 in the nal 12 years of life. Our results show that most markers used to study well-being in old-age vary along both the age and time-to-death dimensions, but some markers are exclusively a function of either time to death or chronological age, and others display different patterns between the sexes

    A spatially and temporally localized sub-laser-cycle electron source

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    We present an experimental and numerical study of electron emission from a sharp tungsten tip triggered by sub-8 femtosecond low power laser pulses. This process is non-linear in the laser electric field, and the non-linearity can be tuned via the DC voltage applied to the tip. Numerical simulations of this system show that electron emission takes place within less than one optical period of the exciting laser pulse, so that an 8 fsec 800 nm laser pulse is capable of producing a single electron pulse of less than 1 fsec duration. Furthermore, we find that the carrier-envelope phase dependence of the emission process is smaller than 0.1% for an 8 fsec pulse but is steeply increasing with decreasing laser pulse duration.Comment: 4 pages, 5 figure

    Sports review: A content analysis of the International Review for the Sociology of Sport, the Journal of Sport and Social Issues and the Sociology of Sport Journal across 25 years

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    The International Review for the Sociology of Sport, the Journal of Sport and Social Issues and Sociology of Sport Journal have individually and collectively been subject to a systematic content analysis. By focusing on substantive research papers published in these three journals over a 25-year time period it is possible to identify the topics that have featured within the sociology of sport. The purpose of the study was to identify the dominant themes, sports, countries, methodological frameworks and theoretical perspectives that have appeared in the research papers published in these three journals. Using the terms, identified by the author(s), that appear in the paper’s title, abstract and/or listed as a key word, subject term or geographical term, a baseline is established to reflect on the development of the sub-discipline as represented by the content of these three journals. It is suggested that the findings illustrate what many of the more experienced practitioners in the field may have felt subjectively. On the basis of this systematic, empirical study it is now possible to identify those areas have received extensive coverage and those which are under-researched within the sociology of sport. The findings are used to inform a discussion of the role of academic journals and the recent contributions made by Michael Silk, David Andrews, Michael Atkinson and Dominic Malcolm on the past, present and future of the ‘sociology of sport’

    Novel Features of Potassium and Sodium Vibrations on Copper Surfaces Observed by High-Resolution Electron-Energy-Loss Spectroscopy

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    High-resolution electron-energy-loss spectra of alkali metals adsorbed on Cu show three unexpected features: the adsorbate-substrate stretching frequency does not change with coverage, within 1 meV on Cu(111) and Cu(110), in agreement with the covalent picture of chemisorption; the spectra show an unusual overtone which is interpreted as a consequence of a strongly non linear relationship between the surface dipole moment and the adsorbate-substrate distance; the dynamical dipole moment is strongly coverage dependent.
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