A new technology for resolving the dynamics of a swinging bat     

Kevin King  Jessandra Hough  Ryan McGinnis  N. C. Perkins 《Sports Engineering》2012,15(1):41-52

Hitting a major league fastball, with approximately half a second to react, poses one of the greatest challenges in sports. The ability to hit the ball derives from the dynamics of the bat swing which can be measured using video motion capture. However, doing so necessitates swinging the bat within the confines of a motion capture laboratory, often with considerable time and expense. This paper introduces an inexpensive and highly portable measurement method for use right on the field of play to support player training, coaching, rehabilitation, and player-bat fitting. The method employs a highly miniaturized, wireless MEMS inertial measurement unit (IMU) affixed to the knob of the bat. The IMU incorporates three-axis sensing of bat acceleration and angular velocity with a low-power RF transceiver to transmit this data to a host computer. Analysis of this data yields a near-instantaneous and highly resolved summary of three-dimensional bat dynamics. This paper describes this novel technology for use in baseball and softball, presents example results, and reveals new features of bat motion overlooked in previous studies.  相似文献   

Feedback effects on oral reading errors of children with learning disabilities   总被引：1，自引：0，他引：1  

V L Perkins 《Journal of learning disabilities》1988,21(4):244-248

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Minimum Competency Testing: What? Why? Why Not?     

Marcy R. Perkins 《Educational Measurement》1982,1(4):5-9

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An empirical examination of the Indian Child Welfare Act and its impact on cultural and familial preservation for American Indian children     

Limb GE  Chance T  Brown EF 《Child abuse & neglect》2004,28(12):1279-1289

OBJECTIVE: Cultural and familial ties are crucial for the overall well-being of children. Extant research and permanency planning practices support the reunification of children with their families when possible. In 1978, the Indian Child Welfare Act (ICWA) was enacted to promote cultural and familial preservation for Indian children, but sparse empirical research has examined the implementation and outcomes associated with this landmark legislation. This article examines the relationship between compliance with ICWA in one Southwestern state and the rate of reunification of Indian children with family or tribal members following out-of-home placement. METHOD: Public child protection records were reviewed for 49 ICWA-eligible children who were placed in alternate care. Data were collected on compliance with placement type, use of qualified expert witnesses, and incorporation of Indian culture and resources. Additionally, 78 state caseworkers and 16 tribal workers were surveyed regarding knowledge and attitudes about three areas of compliance. RESULTS: Case record reviews indicated that the majority (83%) of Indian children were placed according to preferences outlined by ICWA. Almost all cases included a court finding that active efforts were applied to prevent family breakup. While state workers reported limited understanding of many ICWA's requirements, both state and tribal workers reported a high level of state-tribal cooperation in working with Indian families and children. CONCLUSIONS: Results of this study point to two major patterns of findings: (1) individual case record reviews suggest compliance with ICWA; and (2) differences exist in knowledge and perceptions of ICWA by state and tribal workers. Furthermore, state child protection systems should follow the American Indian lead in further emphasizing cultural and familial ties for children. Highlighting such ties acknowledges the importance of reunification and cultural and familial preservation to enable children to have a clear sense of tradition and belonging. Evidence indicates that compliance with ICWA promotes better outcomes through reunification.  相似文献   

The DREAMS Team: Creating community partnerships through research advocacy training for diverse older adults     

Ariel R. Hart  Rebecca Dillard  Molly M. Perkins  Camille P. Vaughan  Kathy Kinlaw  J. Lucas McKay 《Educational gerontology》2017,43(9):440-450

The DREAMS Team research advocacy training program helps clinical faculty and health students introduce basic clinical research concepts to diverse older adults to galvanize their active involvement in the research process. Older adults are frequently underrepresented in clinical research, due to barriers to participation including distrust, historical mistreatment, and their lack of health literacy. The DREAMS Team program aims to involve diverse older adults throughout all phases of research and increase research participation, thereby contributing to the growth of quality patient-centered, evidence-based health care. This course was developed for clinical faculty to deliver to diverse adults aged 55+ in eight 50-minute lectures, followed by half-hour small group discussions moderated by health students. A pilot cohort of 24 individuals was assessed for satisfaction post-program, and self-efficacy before and after the program. Older adult participants improved on a survey measure of self-efficacy, and indicated satisfaction on a post-program questionnaire. All agreed or strongly agreed that they enjoyed participating, and that classes enhanced knowledge/skills about the topics, were high quality, and provided useful information. Twenty-two out of 24 individuals who completed the program indicated they planned to get involved as research advocates. The DREAMS Team program can be offered either on its own, or as a follow-up program to a general health education course led by health students and/or professional researchers or clinicians. Educating older adults about the research process and advocacy through interactive seminars led by congenial and respectful researchers and health students may remove some barriers to research participation and involvement among diverse older adults.  相似文献   

Relationships between executive functioning and homework difficulties in students with and without autism spectrum disorder: An analysis of student- and parent-reports     

Hinke Endedijk  Eddie Denessen  Angélique W. Hendriks 《Learning and individual differences》2011,21(6):765-770

Despite the fact that homework forms an important cornerstone of student development, many students fail to capitalize on the long-term benefits of doing homework. Several executive skills, including cognitive flexibility, monitoring and planning are suggested as prerequisites for the completion of homework. It follows that homework difficulties may relate to such executive functions. A group of particular interest in this respect is students with Autism Spectrum Disorder (ASD), as they are known to suffer from executive dysfunction. The present study examines the extent to which differences in homework difficulties of seventh and eighth grade students with (N = 100) and without ASD (N = 86) may relate to their level of executive functioning. Homework difficulties were examined with student and parent versions of the Homework Difficulties Questionnaire (HDQ) and executive functioning was examined with the Behaviour Rating Inventory of Executive Functioning (BRIEF). In contrast to students with ASD themselves, parents of students with ASD perceived their children to suffer from more homework problems than students without ASD. For both groups, the level of executive functioning was related to the degree of homework difficulty experienced.  相似文献   

School–Community Partnerships,Friend or Foe? The Doublespeak of Community With Educational Partnerships     

Tasha Perkins 《Educational Studies A Journal of the American Educational Studies Association》2015,51(4):317-336

In recent reform efforts, school–community partnerships have been touted as a means for promoting student success (Decker, Decker, &; Brown 2007 Decker, L.E., Decker, V.A., &; Brown, P.M. (2007). Diverse partnerships for student success: Strategies and tools to help school leaders. Lanham, MD: Rowman &; Littlefield Education. [Google Scholar]; Epstein 2010 Epstein, J.L. (2010). School/family/community partnerships: Caring for the children we share. Phi Delta Kappan, 92, 81–96.[Crossref] , [Google Scholar]) and meeting student needs (Hands 2010 Hands, C.M. (2010). Why collaborate? The differing reasons for secondary school educators' establishment of school–community partnerships. School Effectiveness and School Improvement, 21, 189–207.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]). Yet, despite any accolades, the motives and results of school–community partnerships are contested. Gary Anderson (1998 Anderson, G. (1998). Toward authentic participation: Deconstructing the discourses of participatory reforms in education. 715 American Educational Research Journal, 35, 571–603.[Crossref], [Web of Science ®] , [Google Scholar]) points out that partnerships tend to be designed to graft members into prior objectives and goals instead of being designed to facilitate staff members in working together to redefine goals. Auerbach (2010 Auerbach, S. (2010). Beyond coffee with the principal: Toward leadership for authentic school–family partnerships. Journal of School Leadership, 20, 728–757. [Google Scholar]) echoes this concern, suggesting that the literature regarding school partnerships focuses primarily on academic achievement while operating under “limited school agendas or mandates for collaboration” which do little to promote “socially just” schools (p. 729). And, schools are egregiously unjust. Thus, in this article, I first evaluate the school–community partnership in a new light by broadly conceptualizing how community exists as a term within the public education system and considering the impact of the historical situatedness of communities and political lines on renderings of community. Second, I offer an understanding of how school–community partnerships are discussed in terms of doublespeak, illustrating how the very word community can be employed across a spectrum of different meanings, interpretations, and implications. Last, I argue that community partnerships have been promoted as educational reform with little prospect of challenging meta-narratives that tell a story of who has something to offer to our schools and who does not.  相似文献   

Quantifying the effects of load carriage and fatigue under load on sacral kinematics during countermovement vertical jump with IMU-based method     

Ryan S. McGinnis  Stephen M. Cain  Steven P. Davidson  Rachel V. Vitali  Noel C. Perkins  Scott G. McLean 《Sports Engineering》2016,19(1):21-34

We present a method for quantifying sacral kinematics during countermovement jumping (CMJ) using an inertial measurement unit (IMU). The IMU-derived sacral kinematic trajectories reproduced motion capture acceleration, velocity, and displacement to within mean (standard deviation) differences of 0.024 (0.088) m/s², 0.023 (0.026) m/s, and 0.003 (0.032) m, respectively, across 252 jumps performed by 14 subjects. The method also quantified differences in maximum sacral displacement to within 1 % and differences in maximum propulsive velocity to within 0.7 % of motion capture estimates. This builds upon existing IMU-based methods for quantifying jump performance, which do not provide sacral kinematic trajectories. The utility of this method is demonstrated by its ability to discriminate jump performance metrics across a diverse subject population. In particular, we found that 21 participants adopted multiple strategies to maximize jump height in unloaded and loaded fresh conditions, but converged to a common strategy when jumping fatigued and under load. Changes in kinematic parameters were evident across conditions, and several changes were significantly associated with changes in jump performance (i.e., height). These parameters include changes in the depth of the countermovement, duration of the propulsive phase and maximum propulsive velocity. Collectively, these results point toward the future use of this method in naturalistic environments and for multiple objectives including biomechanical performance assessment and tracking, fatigue assessment, and jump training.  相似文献   

Maintaining the transfer of in-service teachers’ training in the workplace     

Eddie W.L. Cheng 《教育心理学》2016,36(3):444-460

Professional training and development is a major component of updating teachers’ pedagogical knowledge and skills. However, transferring such knowledge and skill may not always be successful. Based on the theory of planned behaviour (TPB), the present study has developed a model specifying the factors affecting transfer maintenance intention and behaviour. This model was tested with the partial least square approach to structural equation modelling. The results indicate that the TPB-oriented model is able to explain in-service teachers’ intention to maintain what they have learned from training in their jobs and their subsequent transfer maintenance behaviour. Moreover, the β coefficients indicate that attitude towards the behaviour was the major predictor of transfer maintenance intention, which was in turn the major predictor of transfer maintenance behaviour. Finally, research implications and practical implications have been provided in this study.  相似文献   

Effort Self-Talk Benefits the Mathematics Performance of Children With Negative Competence Beliefs     

Sander Thomaes  Iris Charlotte Tjaarda  Eddie Brummelman  Constantine Sedikides 《Child development》2020,91(6):2211-2220

Children with negative competence beliefs often achieve below their potential in school. This randomized field experiment tested whether engaging in positive self-talk may benefit these children’s mathematics performance. Participants (N = 212, Grades 4–6, M_age = 10.6) worked on the first half of a standardized mathematics test, engaged in effort self-talk (“I will do my very best!”), ability self-talk (“I am very good at this!”), or no self-talk, and worked on the second half of the test. Compared to both the conditions, effort self-talk benefited the performance of children holding negative competence beliefs: It severed the association between negative competence beliefs and poor performance. By internally asserting that they will deliver effort, children with negative competence beliefs can optimize their achievement in school.  相似文献