Racial Discrimination Among NBA Referees

The NBA provides an intriguing place to test for taste-based discrimination: referees and players are involved in repeated interactions in a high-pressure setting with referees making the type of split-second decisions that might allow implicit racial biases to manifest themselves. Moreover, the referees receive constant monitoring and feedback on their performance. (Commissioner Stern has claimed that NBA referees "are the most ranked, rated, reviewed, statistically analyzed and mentored group of employees of any company in any place in the world.") The essentially arbitrary assignment of refereeing crews to basketball games, and the number of repeated interactions allow us to convincingly test for own-race preferences. We find -- even conditioning on player and referee fixed effects (and specific game fixed effects) -- that more personal fouls are called against players when they are officiated by an opposite-race refereeing crew than when officiated by an own-race crew. These biases are sufficiently large that we find appreciable differences in whether predominantly black teams are more likely to win or lose, based on the racial composition of the refereeing crew.

GABRA2, Peer Deviance and Illicit Drug Use in College-Aged Students

Recent studies have shown that single nucleotide polymorphisms (SNPs) in the GABRA2 gene may influence one’s susceptibility to illicit drug use. In order to determine whether an association is present in young adults, we will be performing a study within the Spit for Science research project at Virginia Commonwealth University in Richmond, Virginia. The Spit for Science project aims to understand how genetic and environmental factors come together to influence substance use and emotional health. A cohort of 1523 incoming freshman donated a saliva sample in the fall of 2011 and answered surveys regarding their use of the following categories of drugs: cannabis, sedatives, stimulants, cocaine, or opioids. Follow-up surveys were given during the spring of their freshman year and the spring of their sophomore year. Data on drug abuse was converted to a numerical score between zero and five, depending on how many of the five categories of drugs the respondent had ever tried. We will also be using survey responses to measure the moderating variable of peer deviance. The saliva samples were processed and genotyped for 8 SNPs in the GABRA2 gene. Specific associations will be determined through use of regression analysis. It is hypothesized that the study will show an association between GABRA2 SNPs, illicit drug use, and the additional influence of peer deviance. These findings can be used to improve strategies that aim to decrease drug use among college students and allow them to successfully recover.https://scholarscompass.vcu.edu/uresposters/1081/thumbnail.jp

Severe Emotional and Behavioral Problems: Barriers for Texas Youth Accessing Mental Health Court Programs

Conduct disorder is a constellation of continuous emotional and behavioral problems observed in children and adolescents, which may involve violent and non-violent antisocial behaviors. The symptomology of this psychological disorder includes: disregarding rules without clear reason, cruel or aggressive behavior toward people or animals (e.g., bullying, fighting, using dangerous weapons, forcing sexual activity, and stealing), skipping school, excessive substance use, pathological lying, manipulation, running away, and vandalism (American Psychiatric Association (APA), 2013). Texas Juvenile Mental Health Courts are designed to reduce the number of detained youth, divert at-risk children, maintain community safety, and utilize multidisciplinary approaches to treat conduct disordered youth. However, Texas Juvenile Mental Health Courts deny juveniles admission into their programs if they have a history of violent referrals, property offenses, sexual offenses, or significant gang involvement. This article questions the practice of mental health courts and how this particular practice may directly or indirectly affect youth suffering from conduct disorder. The policy recommendations are discussed after this examination

Controlling for Observed and Unobserved Site Characteristics in Rum Models of Recreation Demand

�Random Utility Maximization (RUM) models of recreation demand are typically plagued by limited information on environmental and other attributes characterizing the available sites in the choice set. To the extent that these unobserved site attributes are correlated with the observed characteristics and/or the key travel cost variable, the resulting parameter estimates and subsequent welfare calculations are likely to be biased. In this paper we develop a Bayesian approach to estimating a RUM model that incorporates a full set of alternative specific constants, insulating the key travel cost parameter from the influence of the unobserved site attributes. In contrast to estimation procedures recently outlined in Murdock (2006), the posterior simulator we propose (combining data augmentation and Gibbs sampling techniques) can be used in the more general mixed logit framework in which some parameters of the conditional utility function are random. Following a series of generated data experiments to illustrate the performance of the simulator, we apply the estimation procedures to data from the Iowa Lakes Project. In contrast to an earlier study using the same data (Egan \textit{et al.} \cite{eganetal}), we find that, with the addition of a full set of alternative specific constants, water quality attributes no longer appear to influence the choice of where to recreate.nonmarket valuation; water quality; discrete choice

The stochastic background: scaling laws and time to detection for pulsar timing arrays

We derive scaling laws for the signal-to-noise ratio of the optimal cross-correlation statistic, and show that the large power-law increase of the signal-to-noise ratio as a function of the the observation time $T$ that is usually assumed holds only at early times. After enough time has elapsed, pulsar timing arrays enter a new regime where the signal to noise only scales as $\sqrt{T}$. In addition, in this regime the quality of the pulsar timing data and the cadence become relatively un-important. This occurs because the lowest frequencies of the pulsar timing residuals become gravitational-wave dominated. Pulsar timing arrays enter this regime more quickly than one might naively suspect. For T=10 yr observations and typical stochastic background amplitudes, pulsars with residual RMSs of less than about $1\,\mu$s are already in that regime. The best strategy to increase the detectability of the background in this regime is to increase the number of pulsars in the array. We also perform realistic simulations of the NANOGrav pulsar timing array, which through an aggressive pulsar survey campaign adds new millisecond pulsars regularly to its array, and show that a detection is possible within a decade, and could occur as early as 2016.Comment: Submitted to Classical and Quantum Gravity for Focus Issue on Pulsar Timing Arrays. 15 pages, 5 figure

A review of in-situ loading conditions for mathematical modelling of asymmetric wind turbine blades

This paper reviews generalized solutions to the classical beam moment equation for solving the deflexion and strain fields of composite wind turbine blades. A generalized moment functional is presented to effectively model the moment at any point on a blade/beam utilizing in-situ load cases. Models assume that the components are constructed from inplane quasi-isotropic composite materials of an overall elastic modulus of 42 GPa. Exact solutions for the displacement and strains for an adjusted aerofoil to that presented in the literature and compared with another defined by the Joukowski transform. Models without stiffening ribs resulted in deflexions of the blades which exceeded the generally acceptable design code criteria. Each of the models developed were rigorously validated via numerical (Runge-Kutta) solutions of an identical differential equation used to derive the analytical models presented. The results obtained from the robust design codes, written in the open source Computer Aided Software (CAS) Maxima, are shown to be congruent with simulations using the ANSYS commercial finite element (FE) codes as well as experimental data. One major implication of the theoretical treatment is that these solutions can now be used in design codes to maximize the strength of analogues components, used in aerospace and most notably renewable energy sectors, while significantly reducing their weight and hence cost. The most realistic in-situ loading conditions for a dynamic blade and stationary blade are presented which are shown to be unique to the blade optimal tip speed ratio, blade dimensions and wind speed

Set theory ontology as an approach to gaming’s composite form

This paper will explore the possibilities that mathematical set theory has to offer the scholarly study of videogames. Videogames are highly heterogeneous objects of study, comprising what Linderoth (2015) has called a ‘composite form’: complex arrangements of material, symbolic and computational capacities. This composite is becoming ever-more heterogeneous, ‘recruiting’ increasingly volatile bodies and relations as computing resources are newly distributed throughout both built and natural environments to create locative, alternate and virtual realities that have been used by designers in various ways (Pokemon Go being only one example)

Computational modelling of structural integrity following mass loss in polymeric charred cellular solids

A novel computational technique is presented for embedding mass-loss due to burning into the ANSYS finite element modelling code. The approaches employ a range of computational modelling methods in order to provide more complete theoretical treatment of thermoelasticity absent from the literature for over six decades. Techniques are employed to evaluate structural integrity (namely, elastic moduli, Poisson’s ratios, and compressive brittle strength) of honeycomb systems known to approximate three-dimensional cellular chars. That is, reducing the mass of diagonal ribs and both diagonal-plus-vertical ribs simultaneously show rapid decreases in the structural integrity of both conventional and re-entrant (auxetic, i.e., possessing a negative Poisson’s ratio) honeycombs. On the other hand, reducing only the vertical ribs shows initially modest reductions in such properties, followed by catastrophic failure of the material system. Calculations of thermal stress distributions indicate that in all cases the total stress is reduced in re-entrant (auxetic) cellular solids. This indicates that conventional cellular solids are expected to fail before their auxetic counterparts. Furthermore, both analytical and FE modelling predictions of the brittle crush strength of both auxetic and conventional cellular solids show a relationship with structural stiffness