Validation of a videogrammetry technique for analysing American football helmet kinematics     

Ann Bailey  James Funk  David Lessley  Chris Sherwood  Jeff Crandall  William Neale 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(5):678-700

ABSTRACT

Professional American football games are recorded in digital video with multiple cameras, often at high resolution and high frame rates. The purpose of this study was to evaluate the accuracy of a videogrammetry technique to calculate translational and rotational helmet velocity before, during and after a helmet impact. In total, 10 football impacts were staged in a National Football League (NFL) stadium by propelling helmeted 50th percentile male crash test dummies into each other or the ground at speeds and orientations representative of concussive impacts for NFL players. The tests were recorded by experienced sports film crews to obtain video coverage and quality typically available for NFL games. A videogrammetry procedure was used to track the position and rotation of the helmet throughout the relevant time interval of the head impact. Compared with rigidly mounted retroreflective marker three dimensional (3-D) motion tracking that was concurrently collected in the experiments, videogrammetry accurately calculated changes in translational and rotational velocity of the helmet using high frame rate (two cameras at 240 Hz) video (7% and 15% error, respectively). Low frame rate (2 cameras at 60 Hz) video was adequate for calculating pre-impact translational velocity but not for calculating the translational or rotational velocity change of the helmet during impact.  相似文献   

Oral History Interview of PCC Founding     

David Reser  Jeanne Drewes  Ann Della Porta 《Cataloging & classification quarterly》2020,58(3-4):239-247

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The Efficacy of Inquiry-Based Instruction in Science: a Comparative Analysis of Six Countries Using PISA 2015     

Oliver  Mary  McConney  Andrew  Woods-McConney  Amanda 《Research in Science Education》2019,51(2):595-616

This study is a comparative analysis of 15-year-old students’ scientific literacy, and its association with the instructional strategies that students experience, across six OECD countries that participated in PISA 2015. Across the six countries, the study investigates the efficacy of inquiry-based instruction in science in contrast with two other instructional approaches to teaching secondary science: adaptive and teacher-directed teaching. The analysis shows that students who reported experiencing high frequencies of inquiry strategies in their classrooms consistently evidenced lower levels of scientific literacy across the six countries. Benchmark analysis also showed, common to all six countries, a strongly positive association between the frequency of teacher-directed and adaptive teaching strategies and students’ scientific literacy. Additionally, the study disaggregates PISA’s composite variable representing inquiry-based instruction and shows that different components of inquiry are differentially associated with students’ scientific literacy. We discuss the implications of these analyses for science teacher educators, science teachers, and educational policy makers. In doing so, we add nuance to our understanding of the efficacy of inquiry-based instruction in science, suggesting that some components, as conceptualised and assessed in PISA, seem to suggest greater attention and use, and others more moderated use.

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Effect of Twinning on Chinese and English Vocabulary Knowledge     

Simpson W.L. Wong  Him Cheung  Mo Zheng  Xiujie Yang  Catherine McBride  Connie Suk-Han Ho  Judy Sze-Man Leung  Bonnie Wing-Yin Chow  Mary Miu Yee Waye 《Child development》2020,91(6):1886-1897

Vocabulary knowledge was tested in a native (Cantonese-Chinese) and foreign (English) language in 150 twins and 150 singletons aged 6–11 years, matched on age, gender, grade level, nonverbal intelligence, parents’ education, family income, and number of siblings and household members. The singletons clearly outperformed the twins on the native vocabulary, but this “twinning effect” was much less noticeable for the foreign vocabulary. The effect on English vocabulary was further reduced after exposure to English at home was controlled. Given that these participants learned most of their English in school rather than home, the present findings support the notion that the twinning effect is associated with increased competition for family interaction in twins compared with singletons.  相似文献   

Building student-teacher relationships and improving behaviour-management for classroom teachers     

Jordan Yassine  Leigh Ann Tipton-Fisler  Barbara Katic 《Support for Learning》2020,35(3):389-407

Teachers can at times view behavioural intervention procedures as time-consuming. Thus, socially-valid classroom-based interventions are a critical component to behavioural success. This study examined the effects of traditional behavioural interventions with two kindergarten students presenting with challenging behaviours, including aggression, tantrums and noncompliance. Notably, it was found that traditional behavioural procedures were not sufficient to substantially reduce the behaviours alone. Therefore, a relationship-building component was added to target positive student-teacher relationships. Student outcomes resulted in a significant reduction in challenging behaviour as well as teacher-reported behaviours showing a reduction across all measured periods. Ongoing teacher consultation, increased student-teacher relationships (STRs) and use of effective classroom management strategies are necessary for effective models of behaviour support.  相似文献   

Female Athlete Triad Coalition risk assessment tool is an evidenced-based tool that is reliable and well-described     

Mary Jane De Souza  Nancy I. Williams  Kristen J. Koltun  Nicole C. A. Strock 《Journal of sports sciences》2020,38(9):996-999

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From apple to abstraction in alphabet books     

Mary Agnes Taylor 《Children‘s Literature in Education》1978,9(4):173-181

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Recipes for fun     

Ann Cole  Carolyn Haas  Elizabeth Heller  Betty Weinberger 《Early Childhood Education Journal》1975,2(4):39-42

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Quality assurance for distance learning: a case study at Brunel University     

Malcolm Clarke  Clive Butler  Peter Schmidt-Hansen  Mary Somerville 《British journal of educational technology : journal of the Council for Educational Technology》2004,35(1):5-11

Brunel University currently has four distance learning MSc courses, with over 500 students registered, and one undergraduate distance learning course. Some have been running for over five years, and well‐established practices have been developed and provide a basis of support for the university. Quality assurance in the university has always been considered in three, equally important, ways: the curriculum and its assessment; the handling of coursework and assignments; and the liaison with students. The lesson we have learned is that a distance learning programme must be based on an existing full‐time MSc programme, which is the gold standard for curriculum and its assessment, and where possible, common examinations and assessment be used. This can be further assured by scrutinisation by the associated research council. This is going to become ever more important with the increasing scrutiny by overseas governments on the academic quality of distance learning courses, which seek assurance on the comparability and quality of degrees. Quality assurance for the handling of coursework and assignments must be secure and demands a high overhead of paperwork. Detailed feedback to students on their assignments is essential, but this can, at the same time, form a quality assurance check for later progression decisions. We also copy and retain approximately 10% of the assignments for the same purpose. Rapid turnaround is essential if feedback is to be timely and therefore useful, and quality checks on processing time should be standard. Quality assurance for the procedures for liaison with distance learning students are somewhat harder to measure quantitatively. The mark of good distance learning must be its tutorial support. This demands good communications. Our own course, entitled Data Communications Systems, benefits from the high proportion of use of electronic communications, namely email, which allows fast turnaround of questions, yet is not intrusive. However, it is deemed essential that hard copy of all such correspondence is kept. Migration to other Internet support services, such as the World Wide Web, videoconferencing and groupware, is inevitable.  相似文献   

The effects of conditioned taste aversions on schedule-induced polydipsia: An analysis of the initiation and postpellet temporal distribution of licking     

Anthony L. Riley  Cora Lee Wetherington  Ashley M. Wachsman  Harris A. Fishman  Mary A. Kautz 《Learning & behavior》1988,16(3):292-298

Animals poisoned following the schedule-induced consumption of saccharin initially continued to drink following spaced pellet deliveries. Neither the initiation of postpellet drinking (i.e., bout, initiation) nor the size and duration of the bouts was effected by the conditioned aversion procedure. With repeated conditioning trials (i.e., repeated pairings of saccharin and LiCl), schedule induced drinking was eventually reduced. The specific components underlying schedule-induced consumption, however, were differentially affected by the aversion training. Specifically, the decrease in schedule-induced drinking was effected primarily by a decrease in licking occurring between 10 and 60 sec after pellet delivery. Bout initiation and licking immediately postpellet (i.e., within the first 10 sec following pellet delivery) were most resistant to suppression and appeared to be responsible for the relative insensitivity of schedule-induced drinking to conditioned taste aversions. The differential effects of taste aversion conditioning on individual components of elicited behavior are discussed.  相似文献