Subject-specific computer simulation model for determining elbow loading in one-handed tennis backhand groundstrokes

A subject-specific angle-driven computer model of a tennis player, combined with a forward dynamics, equipment-specific computer model of tennis ball-racket impacts, was developed to determine the effect of ball-racket impacts on loading at the elbow for one-handed backhand groundstrokes. Matching subject-specific computer simulations of a typical topspin/slice one-handed backhand groundstroke performed by an elite tennis player were done with root mean square differences between performance and matching simulations of < 0.5 degrees over a 50 ms period starting from ball impact. Simulation results suggest that for similar ball-racket impact conditions, the difference in elbow loading for a topspin and slice one-handed backhand groundstroke is relatively small. In this study, the relatively small differences in elbow loading may be due to comparable angle-time histories at the wrist and elbow joints with the major kinematic differences occurring at the shoulder. Using a subject-specific angle-driven computer model combined with a forward dynamics, equipment-specific computer model of tennis ball-racket impacts allows peak internal loading, net impulse, and shock due to ball-racket impact to be calculated which would not otherwise be possible without impractical invasive techniques. This study provides a basis for further investigation of the factors that may increase elbow loading during tennis strokes.     

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.     

Users as service innovators: The case of banking services

Many services can be self-provided. An individual user or a user firm can, for example, choose to do its own accounting - choose to self-provide that service - instead of hiring an accounting firm to provide it. Since users can ‘serve themselves’ in many cases, it is reasonable to suspect that they can also innovate with respect to the services they self-provide - possibly without the assistance of service providers.In this paper, we conduct the first quantitative exploration of the importance of services innovation by users, focusing on the field of commercial and retail banking services. We find that 55% of today's computerized commercial banking services were first developed and implemented by non-bank firms for their own use, and 44% of today's computerized retail banking services were first developed and implemented by individual service users rather than by commercial financial service providers. Manual precursors to these services - manual procedures that carried out functions similar to computerized services in our sample - were almost always developed by users as self-services.Our empirical findings differ significantly from prevalent producer-centered views of service development. We speculate that the patterns we have observed in banking with respect to the major role of users in service development will prove to be quite general. If so, this will be an important matter: on the order of 75% of GDP in advanced economies today is derived from services. We discuss the implications of our findings for research and practice in service development.     

Retrieval constraints and word frequency distributions a log-logistic model for IR

We first present in this paper an analytical view of heuristic retrieval constraints which yields simple tests to determine whether a retrieval function satisfies the constraints or not. We then review empirical findings on word frequency distributions and the central role played by burstiness in this context. This leads us to propose a formal definition of burstiness which can be used to characterize probability distributions with respect to this phenomenon. We then introduce the family of information-based IR models which naturally captures heuristic retrieval constraints when the underlying probability distribution is bursty and propose a new IR model within this family, based on the log-logistic distribution. The experiments we conduct on several collections illustrate the good behavior of the log-logistic IR model: It significantly outperforms the Jelinek-Mercer and Dirichlet prior language models on most collections we have used, with both short and long queries and for both the MAP and the precision at 10 documents. It also compares favorably to BM25 and has similar performance to classical DFR models such as InL2 and PL2.     

Using clinical guidelines to assess the potential value of laboratory medicine in clinical decision-making

IntroductionIt is often quoted that 70% of clinical decisions are based on laboratory results, but the evidence to substantiate this claim is lacking. Since clinical guidelines aim to document best-practice decision making for specific disease conditions, inclusion of any laboratory test means that the best available evidence is recommending clinicians use it. Cardiovascular disease (CVD) is the world’s most common cause of mortality, so this study reviewed all CVD guidelines published by five national/international authorities to determine what proportion of them recommended laboratory testing.Materials and methodsFive leading CVD guidelines were examined, namely the European Society of Cardiology (ESC), the UK National Institute for Health and Clinical Excellence (NICE), the American College of Cardiology (ACC), the Australian Heart Foundation (AHF) and the Cardiac Society of Australia and New Zealand (CSANZ).ResultsA total of 101 guidelines were reviewed. Of the 33 individual ESC guidelines relating to CVD, 24/33 made a direct reference to the use of clinical laboratory tests in either diagnosis or follow-up treatment. The same applied to 15/20 of NICE guidelines, 24/32 from the ACC and 15/16 from the AHF/CSANZ. Renal function and blood count testing were the most recommended (39 and 26 times), with lipid, troponin and natriuretic peptide measurement advocated 25, 19 and 19 times respectively.ConclusionsThis study has shown that laboratory testing is advocated by between 73% and 94% of individual CVD guideline recommendations from five national/international authorities. This provides an index to assess the potential value of laboratory medicine to healthcare.     

Functional fragmentation in city hall and Twitter communication during the COVID-19 Pandemic: Evidence from Atlanta,San Francisco,and Washington,DC

The organization of city government into specialized departments allows cities to accomplish an array of service delivery tasks. Government reformers argue this fragmentation creates coordination challenges when problems spillover the lines of specialized agencies. Functional fragmentation also poses coordination challenges for government communication with the public through social media. The global SARS-CoV-2 pandemic and COVID-19 disease provide an opportunity to investigate the consequences of functional fragmentation in city government for social media communication about public health and pandemic response. A comparative case analysis of three cities using data from city agency Twitter accounts and key informant interviews demonstrates the consequences of fragmentation for internal coordination, as well as public outreach. The experiences of Atlanta, San Francisco, and Washington, DC in the early days of the pandemic provide pragmatic insights for city officials and illustrate the theoretical importance of giving attention to whole of government approaches to city social media communication.     

Why Is This So Hard?: Ideologies of Endangerment,Passive Language Learning Approaches,and Ojibwe in the United States

This paper describes 3 language learning approaches common in many urban and rural Ojibwe communities, as well as the ideologies of endangerment that drive and sustain them. Drawing from collaborative language revitalization work with teachers, learners, and community leaders, we analyze some of the teaching and learning practices that lead to the common mismatch between language learner goals and expectations, on the one hand, and the outcomes of language learning, on the other. We outline how these 3 approaches to language learning relate to cultural identities and place-based notions of authenticity as well as to current findings in the field of second language acquisition. We then profile 2 speakers who have learned Ojibwe successfully as adults to illustrate how their success was possible largely because they were able to engage with the Ojibwe language in interactive ways that run counter to common language learning approaches. We suggest that for language revitalization efforts, and individual learners, to experience higher levels of success, greater attention needs to be paid to how ideologies of endangerment impact language learning approaches.     

Future Sex Educator Perceptions of Rural Versus Urban Instruction: A Case for Community-Centered Sexual Health Education

Instructors of sexual health courses in rural areas face unique challenges as they are often forced to use school-based prevention curricula field-tested in urban areas. Research has yet to consider what future sex educators’ regional expectations are for their profession and how those expectations might have an impact on the classroom. Drawing from interviews with 26 sex-educators-in-training, we find that future educators tended to expect that rural communities would be less diverse, more conservative, and less informed about sexual health matters, even though research demonstrates that today's rural communities inconsistently align with those perceptions.     

Changes in self-reported academic cheating across the transition from middle school to high school

Changes in early adolescents' self-reported cheating behaviors in mathematics before and after the transition from middle school to high school are examined. Students were surveyed in school regarding their cheating behaviors in math, and the motivational goal structures perceived in their math classrooms. Surveys were completed twice during the eighth grade (during middle school) and once at the end of the ninth grade (at the end of the first year in high school). Results indicated that self-reported cheating did not change in the year prior to the high school transition, but that reported cheating increased after the transition. Additional analyses indicated that across the high school transition, self-reported cheating in math increased for students who moved from high mastery to low mastery-oriented classes after the transition, and for students who moved from low performance to high performance-oriented classes; in contrast, self-reported cheating decreased for students who moved from low to high mastery-oriented math classrooms.