Bowling ball dynamics revealed by miniature wireless MEMS inertial measurement unit

This paper presents a novel sensor technology to deduce the dynamics of a bowling ball. The sensor, a miniature wireless inertial measurement unit (IMU), incorporates MEMS accelerometers and angular rate gyros, a microcontroller, a low power RF transceiver, and a rechargeable battery. When embedded in a bowling ball, the IMU transmits the acceleration and angular velocity data that define the dynamics of the ball starting with the bowler’s delivery and its motion in the lane. Example results from professional bowlers illustrate how this technology can be used to assess bowler skill and ball performance. For instance, the IMU accurately measures the spin dynamics of the ball which are crucial to develop the ball “hook.” An analysis of ball dynamics in the lane is distilled to a measurable “hook potential” metric for further assessing bowler skill. Finally, the sensor presented herein is believed to be the world’s smallest, wireless IMU. This highly miniaturized and wireless design will enable parallel training systems for many sports, including basketball, baseball, crew, cricket, golf, fly fishing, soccer, softball, tennis, rowing, among others.     

College attrition and the financial support systems of students

Five groups of undergraduate students, dropouts (academic dismissals), low (GPA) stopouts, high (GPA) stopouts, low (GPA) persisters, and high (GPA) persisters were compared in terms of their responses to a checklist of financial sources of support. Clear sex differences were observed in the reliance on financial sources, either singly or in terms of total sources utilized. Differences related to year in school were also observed. The most significant finding related to attrition was that persisters relied on more sources of support than did withdrawers. This outcome was interpreted in terms of differences between persisters and withdrawers in motivational and personality characteristics that promote the seeking and securing of sources of support.     

Effects of Residential Instability on Head Start Children and Their Relationships with Older Siblings: Influences of Child Emotionality and Conflict between Family Caregivers

This study examined the influence that residential dislocations have on child behavior problems, depression, peer competence, cognitive competence, and the quality of sibling relations in a sample of 70 Head Start children, aged 32 to 67 months, and their older brothers and sisters, aged 48 to 155 months. This was the first study to investigate the sibling relationship in the context of high residential mobility. Information on child characteristics was obtained from mothers and teachers. Sibling data (warmth/harmony and conflict) were obtained from coding videotaped interactions. Child emotionality was found to be an important moderator of the effects of residential mobility on young, poor children and their siblings; caregiver conflict was a less powerful moderator of these effects. Residential instability seemed to compromise the warmth/harmony of the sibling relationship. It was concluded that the effects of residential instability are complex and cannot be understood without considering child characteristics, such as temperament, and the family context in which the child lives.     

Rankings in professional men’s tennis: a rich but underutilized source of information

Abstract

Success in professional tennis is measured, at least in part, by rankings. However, there is little quantitative evidence to inform stakeholders regarding what represents the typical ranking progress of top-ranked players. The objective of this study was therefore to compare the ranking trajectories of male players whom achieved peak professional rankings in the Top 250, 175, 100, 50, 20 and 10. The 11,396 birthdates and weekly professional rankings of all players between 27 August 1973 and 31 October 2011 were collated. The peak ranks for each athlete according to their both chronological age and number of years on tour were identified and athletes were categorised into one of six career–peak ranking bands. One-way analysis of variance tests confirmed distinctive ranking trajectories, which were most pronounced among Top 10 players. The rankings of these players were statistically distinguishable following players’ second year on tour or by 17 years of age. The ranking signature of all Top 100 players emerged as significantly different to players that failed to enter the Top 100 by their fourth year on the tour. Indeed, the representation of ranking as a function of years on tour should be considered for use by tennis policy-makers in the future.     

College attrition,student use of campus facilities,and a consideration of self-reported personal problems

Five groups of undergraduate students, Dropouts (academic dismissals), Low Stopouts (voluntary leavers with low GPA), Low Persisters (continuing students with low GPA), High Stopouts (voluntary leavers with high GPA), High Persisters (continuing students with high GPA), were compared in terms of their use of various campus facilities and their responses to a checklist of personal problems. The High Stopouts and High Persisters did not differ in use of facilities. However, among the low academic performance students, the Low Persisters made significantly greater use of facilities than the Low Stopouts, who, in turn, made significantly greater use of facilities than Dropouts. These findings, for the most part, did not appear to be related to the self-reported importance of personal problems. It was concluded that among low performance students, the broad use of campus services and facilities can be taken as a measure of student integration in the college community.