KINEMATIC ATTRIBUTES ASSOCIATED WITH OVERARM THROWING PERFORMANCE IN CRICKET

The purpose of this study was to identify the kinematic attributes associated with throwing performance (ball velocity and accuracy) in cricket. Three-dimensional motion analysis of sixteen cricketers performing 30 ground-fielding attempts towards a target from three approach directions (straight, non-dominant and dominant) was captured. Vertical release angle, stride length, trunk flexion velocity & forward trunk tilt angle at release were significant predictors of ball velocity across the three approach conditions. Horizontal release angle was a significant predictor of throw accuracy in all three approaches. ANOVAs revealed that throws were significantly quicker from the straight approach, and significantly more accurate in the dominant and straight conditions. Throwing performance and mechanical attributes of throwing technique differ by approach direction constraint

Forecasting severe ice storms using numerical weather prediction: the March 2010 Newfoundland event

The northeast coast of North America is frequently hit by severe ice storms. These freezing rain events can produce large ice accretions that damage structures, frequently power transmission and distribution infrastructure. For this reason, it is highly desirable to model and forecast such icing events, so that the consequent damages can be prevented or mitigated. The case study presented in this paper focuses on the March 2010 ice storm event that took place in eastern Newfoundland. We apply a combination of a numerical weather prediction model and an ice accretion algorithm to simulate a forecast of this event. <br><br> The main goals of this study are to compare the simulated meteorological variables to observations, and to assess the ability of the model to accurately predict the ice accretion load for different forecast horizons. The duration and timing of the freezing rain event that occurred between the night of 4 March and the morning of 6 March was simulated well in all model runs. The total precipitation amounts in the model, however, differed by up to a factor of two from the observations. The accuracy of the model air temperature strongly depended on the forecast horizon, but it was acceptable for all simulation runs. The simulated accretion loads were also compared to the design values for power delivery structures in the region. The results indicated that the simulated values exceeded design criteria in the areas of reported damage and power outages

Experimental Facilities Development

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Sleep patterns alterations, bruxism and DTM in ecstasy users: a controlled study

Users of MDMA (methylenedioxymethamphetamine), a drug popularly known as ecstasy, report feeling tension in the muscles of the face and bruxism in effect of the drug. We compared a group of users of ecstasy (57 people) to a group of non-users (57 persons) in relation to the presence of changes in architecture or sleep disturbances (by polysomnography), signs and symptoms of temporomandibular disorders (TMD evaluated by the RDC - Research Diagnostic Criteria), bite force, pattern and context of use of ecstasy and other psychoactive substances and associate problems (measured by DUSI-R - Drug Use Screening Inventory Revised). Volunteers were people aged 18 to 40 years, of both sexes, with natural dentition and no history of trauma (cervical or facial), hormonal or neurological disorders, or psychoactive substances dependence (except ecstasy in the experimental group) and not were using drugs acting on the central nervous system. The group of ecstasy users had a higher percentage of stage 3 sleep, less time awake, high number of oxygen desaturations, increased number of episodes of periodic legs moviments, the greater presence of snoring and bruxism phasic. No were found clinically significant differences between groups in symptoms of TMD. The ecstasy users also had higher rates of problems with the use of other psychoactive substances, a higher proportion of relationship problems and adjustment to work. Among users of ecstasy users who were also at risk of alcohol, the presence of bruxism was more pronounced. This confirms in part the association between use of ecstasy and bruxism, which is more evident under the influence of drugs and more rare in the period after cessation of use.Os usuários de MDMA (metilenodioximetanfetamina), droga popularmente conhecida como êxtase, relatam sentir tensão na musculatura do rosto e bruxismo sob efeito da droga. Comparamos um grupo de usuários de êxtase (57 pessoas) a um grupo de não usuários (57 pessoas) em relação à presença de alterações na arquitetura ou distúrbios do sono (por meio de exame de polissonografia); sinais e sintomas de Disfunção Temporomandibular (DTM, avaliados pelo RDC - Research Diagnostic Criteria); força de mordida; padrão e contexto de uso de êxtase e de outras substâncias psicoativas e problemas associados (avaliados pelo DUSI–R - Drug Use Screening Inventory revisado). Foram voluntárias pessoas com idade de 18 a 40 anos, de ambos os sexos, com dentição natural, sem história pregressa de traumas (cervicais ou faciais); distúrbios neurológicos ou hormonais; dependência de substâncias psicoativas (exceto êxtase no grupo experimental) e que não estivessem utilizando medicamentos com ação sobre o sistema nervoso central. O grupo de usuários de êxtase apresentou maior porcentagem de estágio 3 do sono; menor tempo em vigília; maior número de dessaturações de oxigênio, maior número de episódios de movimento periódico das pernas, maior presença de ronco e de bruxismo fásico. Não foram detectadas diferenças clinicamente significativas entre os grupos em relação aos sintomas de DTM. Os usuários de êxtase também apresentaram maior índice de problemas em relação ao consumo de outras substâncias psicoativas, maior proporção de problemas de relacionamento e de adaptação ao trabalho. Entre os usuários de êxtase que também eram usuários de risco de álcool, a presença de bruxismo foi mais acentuada. Desta forma, confirma-se parcialmente a associação entre o uso de êxtase e bruxismo, que é mais evidente sob o efeito da droga e mais rara no período após a cessação do uso.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP: 2004/11301-2TEDEBV UNIFESP: Teses e dissertaçõe

Comparison of IMU Measurements of Curling Stone Dynamics with a Numerical Model

Abstract Despite almost a century of research, the question of what causes a curling stone to curl (move perpendicular to its initial direction of motion) has no complete answer. Many hypotheses have been formulated, but none has been able to account quantitatively for the full magnitude of the observed curl. The objective of this research was to equip a curling stone with an inertial measurement unit (IMU) and measure its motion, in order to verify a previously published, numerical model of curling stone dynamics. Low cost, small size, accuracy, ease of programming and operation, wireless data communication, and a data-sampling rate near 1 kHz, were selection criteria and constraints for the instrument package. We used the MicroStrain 3DM-GX4-25 system. This is a MEMS-based IMU with a tri-axial gyroscope and a tri-axial linear accelerometer. It was mounted and interfaced with a Bluetooth transmitter, on a curling stone handle. The data were streamed to a host laptop and displayed graphically in real time. Post-processing of the data included filtering and time-integration in order to obtain linear and angular velocities, and displacements. We have compared our experimental results with trajectory data calculated using a previously published numerical model, based on a thermodynamic approach to ice friction. While the observed longitudinal and angular motions are captured reasonably well by the model (errors of about 5% or less), no curl is predicted by the model

Symbolic knowledge extraction from trained neural networks: A sound approach

Although neural networks have shown very good performance in many application domains, one of their main drawbacks lies in the incapacity to provide an explanation for the underlying reasoning mechanisms. The “explanation capability” of neural networks can be achieved by the extraction of symbolic knowledge. In this paper, we present a new method of extraction that captures nonmonotonic rules encoded in the network, and prove that such a method is sound. We start by discussing some of the main problems of knowledge extraction methods. We then discuss how these problems may be ameliorated. To this end, a partial ordering on the set of input vectors of a network is defined, as well as a number of pruning and simplification rules. The pruning rules are then used to reduce the search space of the extraction algorithm during a pedagogical extraction, whereas the simplification rules are used to reduce the size of the extracted set of rules. We show that, in the case of regular networks, the extraction algorithm is sound and complete. We proceed to extend the extraction algorithm to the class of non-regular networks, the general case. We show that non-regular networks always contain regularities in their subnetworks. As a result, the underlying extraction method for regular networks can be applied, but now in a decompositional fashion. In order to combine the sets of rules extracted from each subnetwork into the final set of rules, we use a method whereby we are able to keep the soundness of the extraction algorithm. Finally, we present the results of an empirical analysis of the extraction system, using traditional examples and real-world application problems. The results have shown that a very high fidelity between the extracted set of rules and the network can be achieved

Women at risk for sexually transmitted diseases: correlates of intercourse without barrier contraception

Objective: The purpose of this study was to evaluate the correlates of vaginal intercourse without barrier contraception (unprotected intercourse). Study Design: Baseline data from a randomized trial were analyzed to evaluate factors that are associated with intercourse without barrier method use among women \u3c35 years old. Logistic regression models provided estimates of the association of demographic, reproductive, and sexual history variables with unprotected intercourse. Results: Intercourse without barrier contraception was common; 65% of participants had ≥2 episodes of intercourse without barrier contraception use in the past month. Factors that were associated with increased odds of unprotected intercourse included the number of coital episodes, a male partner’s unwillingness to use condoms (adjusted odds ratio, 4.1; 95% CI, 2.3-6.9), and, among women \u3c20 years old, low condom use self-efficacy score (adjusted odds ratio, 1.6; 95% CI, 1.0-2.9). Conclusion: Risk factors for unprotected intercourse included coital frequency and the male partner’s unwillingness to use condoms. Self-efficacy for condom use was especially important for women \u3c20 years old

Measurement of Analyzing Power for Proton-Carbon Elastic Scattering in the Coulomb-Nuclear Interference Region with a 22-GeV/c Polarized Proton Beam

The analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region of momentum transfer, $9.0\times10^{-3}<-t<4.1\times10^{-2}$ (GeV/$c)^{2}$, was measured with a 21.7 GeV/$c$ polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to non-flip amplitude, $r_5$, was obtained from the analyzing power to be $\text{Re} r_5=0.088\pm 0.058$ and $\text{Im} r_5=-0.161\pm 0.226$.Comment: 4 pages, 4 figures and 1 table. Accepted by Physical Review Letter

Cooler Experiment Preparation

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Interaction of Stored, Cooled Proton Beams with Fiber Targets

This research was sponsored by the National Science Foundation Grant NSF PHY-931478