Coupled Replicator Equations for the Dynamics of Learning in Multiagent Systems

Starting with a group of reinforcement-learning agents we derive coupled replicator equations that describe the dynamics of collective learning in multiagent systems. We show that, although agents model their environment in a self-interested way without sharing knowledge, a game dynamics emerges naturally through environment-mediated interactions. An application to rock-scissors-paper game interactions shows that the collective learning dynamics exhibits a diversity of competitive and cooperative behaviors. These include quasiperiodicity, stable limit cycles, intermittency, and deterministic chaos--behaviors that should be expected in heterogeneous multiagent systems described by the general replicator equations we derive.Comment: 4 pages, 3 figures, http://www.santafe.edu/projects/CompMech/papers/credlmas.html; updated references, corrected typos, changed conten

До питання про співвідношення праворозуміння та правової думки

У статті проаналізовано структуру праворозуміння, дано визначення поняття правова думка та вказано, що праворозуміння, як осмислення правової дійсності є складовою частиною правової думки.В статье проанализировано структуру правопонимания, дано определение понятия правовая мысль иопределено, что правопонимание как осмысление правовой действительности является составляющей правовой мысли.In the article are analyzed the structure of legal understanding, given the definition of legal thought and determined that the legal comprehension as a legal interpretation of reality is a part of legal thought

A new parameterization of the Effective Temperature for L-band Radiometry.

An accurate value of the effective temperature is critical for soil emissivity retrieval, and hence soil moisture content retrieval, from passive microwave observations. Computation of the effective temperature needs fine profile measurements of soil temperature and soil moisture. The availability of a two year long data set of these surface variables from SMOSREX (Surface Monitoring Of the Soil Reservoir EXperiment) makes it possible to study the effective temperature at the seasonal to interannual scale. This study shows that present parameterizations do not adequately describe the seasonal variations in sensing depth. Therefore, a new parameterization is proposed that is stable at the seasonal to interannual scales while retaining simplicity. Copyright 2006 by the American Geophysical Union

Association between concussion and mental health in former collegiate athletes

Background: The existing research on the association between concussion and mental health outcomes is largely limited to former professional athletes. This cross-sectional study estimated the association between recurrent concussion and depression, impulsivity, and aggression in former collegiate athletes. Methods: Former collegiate athletes who played between 1987–2012 at a Division I university completed an online questionnaire. The main exposure, total number of self-recalled concussions (sport-related and non-sport-related), were categorized as: zero (referent), one, two, or three or more concussions. The main outcomes were the depression module of The Patient Health Questionnaire (PHQ-9), the Short Form of the Barratt Impulsiveness scale (BIS15); and the 12-item Short Form of the Buss-Perry Aggression Questionnaire (BPAQ-SF). Depression was categorized into a binomial severity classification that differentiated between no or mild depression (PHQ-9 scores <10) and moderate to severe depression (PHQ-9 scores ≥10). Impulsivity and aggression were kept as continuous outcomes. Binomial regression estimated adjusted prevalence ratios (PR). Linear regression estimated adjusted mean differences (MD). Results: Of the 797 respondents with complete data (21.9% completion rate), 38.8% reported at least one concussion. Controlling for alcohol dependence and family history of depression, the prevalence of moderate to severe depression among former collegiate athletes reporting three or more concussions in total was 2.4 times that of those reporting zero concussions [95% Confidence Interval (CI): 1.0, 5.7]. Controlling for alcohol dependence, family history of anxiety, relationship status, obtaining a post-graduate degree, and playing primary college sport professionally, former collegiate athletes reporting two or more concussions in total had higher mean scores for impulsivity, compared to those reporting no concussions (2 concussions MD = 2.7; 95% CI: 1.2, 4.1; 3+ concussions MD = 1.9; 95% CI: 0.6, 3.2). Controlling for alcohol dependence, sex, and relationship status, former collegiate athletes reporting three or more concussions in total had a higher mean score for aggression, compared to those reporting no concussions (MD = 3.0; 95% CI: 1.4, 4.7). Conclusions: Our study found an association between former concussion and greater risk of severe depression and higher levels of impulsivity and aggression among former collegiate athletes. Additional prospective studies better addressing causality and ascertaining valid lifetime concussion histories and medical histories are needed

Agreement between athlete-recalled and clinically documented concussion histories in former collegiate athletes

Background: Athlete-recalled and clinically documented concussion histories have been used in research on former athletes, but both have limitations. Comparisons of these 2 types of concussion histories are needed to improve the accuracy of estimates of concussion history for future research and clinical care. Purpose: To estimate the agreement between athlete-recalled and clinically documented concussion histories during college and to explore reasons for differences. Study: Cohort study (diagnosis); Level of evidence, 3. Methods: Athlete-recalled concussion histories were provided by a convenience sample of 130 former collegiate athletes using an online questionnaire, and they were individually linked to previously collected clinical data that tracked medically diagnosed concussions at the host institution from 1996 to 2012. The intraclass correlation coefficient (ICC2,1) was used to assess agreement between athlete-recalled and clinically documented concussion histories. Descriptive analyses were performed to assess reasons for disagreement. Results: Agreement between athlete-recalled and clinically documented concussion histories was low (ICC2,1 = 0.21; 95% confidence interval, 0.05-0.37), but it was higher for women (ICC2,1 = 0.65; 95% confidence interval, 0.44-0.79) and for athletes playing more recently (2005-2012; ICC2,1 = 0.39; 95% confidence interval, 0.01-0.67). Of the 53 athletes who self-reported college sportsrelated concussions, 40% believed that they sustained impacts that should have been diagnosed as concussions but were undetected, and 21% admitted nondisclosure of suspected concussions. Common reasons for nondisclosure included the following: did not think injury was serious enough (91%), did not know it was a concussion (73%), and did not want to leave the game/practice (73%). Conclusion: Given the low agreement between athlete-recalled and clinically documented concussion histories, methodologic research is needed to improve the quality of tools used to assess concussion histories in former athletes. © 2014 The Author(s)

HAPEX-Sahel : a large-scale study of land-atmosphere interactions in the semi-arid tropics

The Hydrologic Atmospheric Pilot EXperiment in the Sahel (HAPEX-Sahel) was carried out in Niger, West Africa, during 1991 - 1992, with an intensive observation period (IOP) in August - October 1992. It aims at improving the parameterization of land surface atmosphere interactions at the Global Circulation Model (GCM) gridbox scale. The experiment combines remote sensing and ground based measurements with hydrological and meteorological modelling to develop aggregation techniques for use in large scale estimates of the hydrological and meteorological behaviour of large areas in the Sahel. The experimental strategy consisted of a period of intensive measurements during the transition period of the rainy to the dry season, backed up by a series of long term measurements in a 1° by 1° square in Niger. Three &quot;supersites&quot; were instrumented with a variety of hydrological and (micro) meteorological equipment to provide detailed information on the surface energy exchange at the local scale. Boundary layer measurements and aircraft measurements were used to provide information at scales of 100 - 500 km2. All relevant remote sensing images were obtained for this period. This programme of measurements is now being analyzed and an extensive modelling programme is under way to aggregate the information at all scales up to the GCM grid box scale. The experimental strategy and some preliminary results of the IOP are described

Gender moderates the relationship between empathy and aggressiveness in sport: The mediating role of anger

This research investigated whether gender moderates, and anger mediates, the relationship between empathy (i.e., perspective taking and empathic concern) and aggressiveness in sport. In Study 1, perspective taking and empathic concern were negatively associated with aggressiveness, and this effect was stronger in women compared to men. In Study 2, perspective taking was a negative predictor of aggressiveness and antisocial behavior in sport, and anger mediated these relationships in women, but not in men. Our findings suggest that empathy and emotion-based strategies targeted at reducing aggressiveness in sport need to be tailored for males and females

The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school boys' ice hockey (2008-2009 through 2013-2014) and National Collegiate Athletic Association men's and women's ice hockey (2004-2005 through 2013-2014)

Context: Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided efforts to collect data on ice hockey injuries. Objective: To describe the epidemiology of injuries sustained in high school boy's ice hockey in the 2008-2009 through 2013-2014 academic years and collegiate men's and women's ice hockey in the 2004-2005 through 2013-2014 academic years using Web-based surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance of ice hockey teams of high school boys (annual average ¼ 34), collegiate men (annual average ¼ 20), and collegiate women (annual average ¼ 11). Patients or Other Participants: Boys', men's, and women's ice hockey players who participated in practices and competitions during the 2008-2009 through 2013-2014 high school academic years or the 2004-2005 through 2013-2014 collegiate academic years. Main Outcome Measure(s): Athletic trainers collected time-loss (24 hours) injury and exposure data. We calculated injury rates per 1000 athlete-exposures (AEs), injury rate ratios (IRRs) with 95% confidence intervals (CIs), and injury proportions by body site and diagnosis. Results: The High School Reporting Information Online system documented 831 boys' ice hockey time-loss injuries during 356 997 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 2611 men's ice hockey time-loss injuries during 552 642 AEs and 752 women's ice hockey injuries during 232 051 AEs. Injury rates were higher in collegiate men than in high school boys during 2008-2009 through 2013-2014 (4.38 versus 2.33/1000 AEs; IRR ¼ 1.88; 95% CI ¼ 1.73, 2.05) and collegiate women during 2004-2005 through 2013-2014 (IRR ¼ 1.46; 95% CI ¼ 1.34, 1.58). Most injuries occurred during competitions (boys ¼ 80.0%, men ¼ 66.9%, women ¼ 55.3%); injury rates were higher in competitions than in practices for boys (IRR ¼ 8.14; 95% CI ¼ 6.87, 9.65), men (IRR ¼ 6.58; 95% CI ¼ 6.06, 7.13), and women (IRR ¼ 3.63; 95% CI ¼ 3.14, 4.19). At all levels, most injuries occurred to the head/face and shoulder/clavicle and resulted in concussions, contusions, or ligament sprains. Conclusions: Injury rates varied across sports but were consistently higher in competitions than in practices. In competitions, concussions were common injuries, highlighting the need for continued development of injury-prevention strategies