Comparison of advanced and intermediate 200-m backstroke swimmers' dominant and non-dominant shoulder entry angles across various swimming speeds

During backstroke, an optimum shoulder entry angle of 180° has been anecdotally suggested; however, this has yet to be investigated biomechanically. The aim of this study was to quantify shoulder entry angles for advanced and intermediate backstroke swimmers. Six advanced (season's best?<150?s) and six intermediate (season's best?>160?s) 200-m backstroke swimmers had markers applied to the medial humeral epicondyles and glenoid cavities. Following a familarization period, participants completed backstroke swimming trials (90?s each) in a swimming flume at 50%, 60%, 70%, and 80% of their season's best 200-m velocity. A camera positioned above the flume recorded frontal plane motion, which was digitized and analysed in Simi Motion Systems. The mean peak angle between the upper arm and the line of progression was established in ten strokes for each participant. The results showed backstroke shoulder entry angles for advanced swimmers (170°) were significantly closer to the suggested optimum 180° compared with those of intermediate swimmers (161°). The non-dominant arm displayed values closer to the optimum (171°), while swimming speed had no effect on backstroke shoulder entry angle. In conclusion, backstroke shoulder entry angle may help discriminate between advanced and intermediate backstroke swimmers and may be influenced by laterality dominance, being independent of swimming speed.     

Facilitators and inhibitors for integrating expertise diversity in innovation teams: The case of plasmid exchange in molecular biology

Innovation increasingly relies on collaboration in teams instead of individual efforts. Although the advantages of teams for innovating are virtually undisputed, we have only a very rudimentary understanding of their success drivers. To shed more light on innovation teams, we conceptualize multiplicity in expertise as nonredundant expertise and distinguish it from factors that facilitate or hinder the integration of this expertise. These factors are overlap in expertise, disparity in team members’ status, and whether or not teams use automation technology. We use the empirical context of molecular biology, especially the part of this field in which teams produce and exchange genetic material in the form of so-called plasmids. Combining data about plasmids from a central plasmid repository (AddGene) with bibliometric data endows us with a rich dataset capturing information about team diversity in addition to two innovation performance measures (the number of plasmid orders and the number of citations attracted by publications). Our analysis shows that multiplicity in expertise increases innovation performance; this relationship is strengthened by the overlap in expertise and weakened by disparity in status and the use of the automation technology. Our paper provides a more detailed theory of expertise diversity and contributes to the diversity literature. Our findings also lead to implications for practitioners.     

What makes a youth-produced film good? The youth audience perspective

In this article, we explore how youth audiences evaluate the quality of youth-produced films. Our interest stems from a dearth of ways to measure the quality of what youth produce in artistic production processes. As a result, making art in formal learning settings devolves into either romanticized creativity or instrumental work to improve skills in core content areas. We conducted focus groups with 38 youth participants where they viewed four different films produced by the same youth media arts organization that works with young people to produce short-form, autobiographical documentaries. We found that youth focused their evaluations on identifying the films' genre and content and on assessing how well the filmmakers' creative decisions fit with identifications of genre and content. Evaluations were mediated by audiences' expectations and seemed to inform judgments of quality and creativity. We hope that our work can inform the design of formal learning spaces where young people are producing narrative art.     

School Start Time Change: An In‐Depth Examination of School Districts in the United States

In response to the scientific evidence documenting both profound developmental changes in sleep and circadian biology during adolescence and the myriad of negative health, performance, and safety outcomes risks associated with chronic sleep loss, at least 70 public school districts in the United States, representing approximately 1,000 schools, have successfully implemented a delay in high school start times. However, despite the compelling evidence supporting school start time change as a key strategy in addressing the epidemic of adolescent sleep loss, many school districts across the country with early high school start times have not considered the option to implement later bell schedules for adolescents. Moreover, while the current scientific literature has clearly documented the positive outcomes associated with delayed high school start times, these studies contain limited information regarding the process by which school districts consider, approve and implement bell schedule changes. Thus, this in‐depth examination of those school districts that have been successful in changing their bell schedules is intended to support the efforts of other districts in various stages of contemplating this measure. We utilized a multi‐pronged approach (literature review, case studies, telephone interviews, online survey) to summarize the experiences of school districts across the United States in regard to challenges faced, strategies employed, and lessons learned in the hope that this information will be a useful tool for other school districts looking to chart a course forward to promote the health, safety, and academic opportunities of their students.     

Professional community and the problem of high school reform

A two-year qualitative study of mathematics and English teachers in two urban comprehensive high schools investigated how teacher community serves as resource for teacher development and school reform. A school engaged in whole-school reform sustained high teacher commitment and school-level community by constituting professional community strongly at the school level, but its departments displayed varying capacity and disposition to examine problems of teaching and learning at the classroom level. In the second school, innovative teacher communities were constituted strongly at the department level in English and mathematics, but suffered problems of stress and turnover due to weak organizational supports for teacher development and school reform. Findings point both to the potential contribution of professional communities situated in subject departments and the challenge of capitalizing on such communities to advance whole-school reform. The study suggests complex relationships among organizational context, teacher community, teacher development, and institutional reform.