利用PVM实现整体光照的并行计算     

孙济洲 《天津大学学报(英文版)》2002,8(3):178-182

对利用网络资源解决复杂且耗时的计算问题做了尝试 .选择典型的粒子跟踪整体光照计算问题作为研究对象 ,提出一种改进的且充分发掘其内在相关特性的密度估计算法 .在以太网连接的多台微机上 ,以PVM (并行虚拟机 )机制实现了该算法的并行计算 .通过对各项运算性能指标的测试与分析 ,结果显示可获得良好的加速比 ,并且PVM在分布式网络并行计算上将有很好的应用前景  相似文献   

Profiles of Childhood Maltreatment: Associations with Sexual Risk Behavior during Adolescence in a Sample of Racial/Ethnic Minority Girls     

Li Niu  Joshua Brown  Lindsay Till Hoyt  Anthony Salandy  Anne Nucci-Sack  Viswanathan Shankar  Robert D. Burk  Nicolas F. Schlecht  Angela Diaz 《Child development》2021,92(4):1421-1438

This study examines associations between childhood maltreatment and developmental trajectories of sexual risk behaviors (SRBs) in a sample of 882 sexually active adolescent girls, predominantly Hispanic or Black, assessed every 6 months between 13 and 23 years. Latent profile analyses revealed four distinct maltreatment profiles: Low Maltreatment (76%), Moderate Emotional Neglect Only (15%), Severe Physical/Emotional Abuse (3%), and Severe Sexual Abuse (6%). Multilevel growth analyses showed the Moderate Emotional Neglect Only and Severe Sexual Abuse profiles exhibited more SRBs starting in late adolescence, and the Severe Sexual Abuse profile also exhibited a faster increase than the Low Maltreatment profile. Understanding heterogeneity within maltreated populations may have important implications for healthy sexual development.  相似文献   

Aging and tennis playing in a coincidence-timing task with an accelerating object: the role of visuomotor delay     

Lobjois R  Benguigui N  Bertsch J 《Research quarterly for exercise and sport》2005,76(4):398-406

The purpose of the present study was to determine whether playing a specific ball sport, such as tennis, could maintain the coincidence-timing (CT) performance of older adults at a similar level to that of younger ones. To address this question, tennis players and nonplayers of three different age ranges (ages 20-30, 60-70, and 70-80 years) performed a simple CT task consisting of timing their response (pressing a button) to coincide with the arrival of a stimulus at a target. The stimulus moved at either an accelerating, constant, or decelerating velocity. As expected, all participants were affected by the velocity manipulation, which led to late and early responses to accelerating and decelerating stimuli, respectively. Whereas this response bias was increasingly pronounced with advancing age in nonplayers, no difference was found among player groups of different ages. Finally, we showed that the length of the visuomotor delay could explain the effect of nonconstant velocities.  相似文献   

The complex route to success: complex problem-solving skills in the prediction of university success     

Matthias J. Stadler  Nicolas Becker  Samuel Greiff  Frank M. Spinath 《高等教育研究与发展》2016,35(2):365-379

Successful completion of a university degree is a complex matter. Based on considerations regarding the demands of acquiring a university degree, the aim of this paper was to investigate the utility of complex problem-solving (CPS) skills in the prediction of objective and subjective university success (SUS). The key finding of this study was that CPS was not only strongly correlated to objective university success but also explained university grade point averages (GPA) of N?=?78 German business students even after intelligence and high-school GPA were controlled for. In addition, priority setting while working on a complex problem explained self-rated SUS. Given this incremental validity over the most established predictors of objective university success and its versatility, we argue that CPS may be a valuable addition to existing predictors in university applicant selection.  相似文献   

Increased exhaled breath condensate 8-isoprostane after a swimming session in competitive swimmers     

Mathieu C. Morissette  Nicolas Murray  Julie Turmel  Julie Milot  Louis-Philippe Boulet 《European Journal of Sport Science》2016,16(5):569-576

Objectives: This study aimed to evaluate the levels of 8-isoprostane (8-IsoP) in the airways of competitive swimmers at baseline and after a swimming session according to their airway responsiveness. Methods: Twenty-three swimmers and six lifeguards had a baseline spirometry and bronchoprovocative challenges. During a second visit, swimmers performed a usual swimming session while lifeguards stayed in the same pool environment for the same time period. Forced expiratory volume in one second (FEV₁) was measured before and 5 min after the end of the session. Exhaled breath condensate (EBC) was sampled before and 10 min after the session and EBC 8-IsoP levels were analysed by enzyme immunoassay. Change in EBC 8-IsoP from baseline to post-swimming session was calculated. Results: We observed no relationships between airway hyper-responsiveness and 8-IsoP values before or after swimming in swimmers. The levels of 8-IsoP were significantly higher after the training session (mean value 2.9, s?=?0.5 pg?mL^?1) than at baseline (mean value 1.9, s?=?0.4 pg?mL^?1) in swimmers only (p?=?.012). EBC 8-IsoP levels after the swimming session significantly correlated with the percent change in FEV₁ after swimming. Conclusions: EBC 8-IsoP levels were increased after training in swimmers but not in lifeguards, suggesting that exercise-induced hyperpnoea in a chlorinated pool environment increases airways oxidative stress.  相似文献   

Implicit measures of beliefs about sport ability in swimming and basketball     

Nicolas Mascret  Jean-Louis Falconetti  François Cury 《European Journal of Sport Science》2016,16(3):358-364

Sport ability may be seen as relatively stable, genetically determined and not easily modified by practice, or as increasable with training, work and effort. Using the Implicit Association Test (IAT), the purpose of the present study is to examine whether the practice of a particular sport (swimming or basketball) can influence automatic beliefs about sport ability in these two sports. The IAT scores evidence that swimmers and basketball players automatically and implicitly associate their own sport with training rather than genetics, whereas non-sportspersons have no significant automatic association. This result is strengthened when perceived competence and intrinsic motivation in swimming or basketball are high.  相似文献   

Conceptual and critical development in student teachers: first steps towards an integrated comprehension of osmosis     

Laurence Viennot  Nicolas Décamp 《International Journal of Science Education》2016,38(14):2197-2219

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Domain Specificity,Task Specificity,and Expert Performance     

Mark A. Williams  Julian D. Ward  Paul Ward  Nicolas J. Smeeton 《Research quarterly for exercise and sport》2013,84(3):428-433

Abstract

Initial performance, final performance, and the amount of learning in 50 trials of the rho test motor performance task were obtained on 120 boys and girls, aged 10 and 14. Initial and final performance showed significant age, sex, and age w/i sex differences. The amount of learning showed no differences.  相似文献   

The Music Industry in the Digital Era: Toward New Contracts     

Nicolas Curien  François Moreau 《Journal of Media Economics》2013,26(2):102-113

Digital piracy, although negatively altering the recorded music market, has a positive impact on other segments of the music market, such as live music or ancillary goods, because it generates a positive externality benefiting those activities. Through a 2-player strategic game between a record company and an artist, this study shows that a renegotiation of music contracts could allow the internalizing of this positive externality, while being welfare-improving for both record companies and artists. This study also shows, however, that pervasive piracy is not desirable for an artist.  相似文献   

Lives of a Blockbuster Drug     

Nicolas Rasmussen 《Minerva》2006,44(2):229-234

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