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91.
We tested the hypothesis that variability in the timing of ball release in overarm throws affects ball speed. Nine unskilled and six skilled throwers made 30 throws fast and accurately from a sitting and standing position. Angular positions of finger and arm segments were recorded with search-coils at 1000 Hz; ball speed was measured with a radar gun. The time of ball release from the fingertips was measured with respect to seven arm kinematic reference points. Mean timing windows for ball release were 28 ms for unskilled throwers and 7 ms for skilled throwers. Mixed-model analyses of variance showed that a there was a statistically significant relationship between ball speed and the timing of ball release in unskilled throwers, but not in skilled throwers. This was presumably due to the difference in variability of the timing of ball release between the two groups. In contrast, skilled throwers showed a relationship between ball speed and peak forearm angular velocity (one measure of arm speed). We conclude that although variability in the timing of ball release can affect ball speed, this is only a major factor in unskilled throwers. When skilled throwers throw fast, variability in ball speed is due to variability in arm speed.  相似文献   
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Do physical activity beliefs differ by age and gender?   总被引:1,自引:0,他引:1  
Age and gender are consistently related to physical activity (PA), yet theoretical explanation for these associations is scant. The present study compared the mean values and correlations of a population sample, divided by gender and age group, with respect to theory of planned behavior beliefs (behavioral, normative, and control) and PA. Participants were a sample (N=6,739) of adults (M age=49.65, SD=16.04) who completed measures of social and health demographics, theory of planned behavior beliefs, and self-reported PA. Mean analyses identified greater perceived control over PA for seniors than for young and middle-aged adults (N>.025). Belief-behavior correlations, however, were not different across age and gender in 24 of 26 tests (q<.19). Thus, PA beliefs are invariant across age and gender with the exception of mean levels of perceived control, which are lower among younger adults than older adults. Factors such as early parenthood and career demands were considered the likely reasons for differences. Overall, the evidence suggests that adapting theoretical models for specific age groups or based on gender may not be necessary.  相似文献   
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Abstract: Food science laboratory courses are traditionally taught as a series of preplanned laboratories with known endpoints. In contrast, inquiry‐guided (IG) laboratories allow students to ask questions, think through problems, design experiments, then adapt and learn in response to unexpected results. This study examined the effects of converting the course, “Analytical Techniques in Food and Bioprocessing Sciences” from a traditional approach (2008 to 2010 data) to an IG approach (2011 data) by assigning teams of 2–3 students a food and a set of 5 analyses to conduct over the course of the semester. Students were required to choose and justify the use of specific methods for each analysis, as well as to develop a supply list and a budget for the semester‐long project. During the semester, students were required to post and discuss their weekly progress with the instructor, teaching assistants, and the rest of the class using an online discussion forum. At the end of the semester, students were required to present the results of their analysis in both oral and written formats. Overall course grades were significantly higher (P≤ 0.05) using IG in 2011 compared to 2010 and 2009, but not to 2008 grades. Numerical course evaluations for the instructor, overall course, and lab, as well as written course evaluations all significantly (P≤ 0.05) improved. This suggests that an IG approach may measurably improve student performance in terms of course grades and the ability to complete semester long projects. It may also increase student satisfaction with the course, as measured by numerical and written end of semester surveys.  相似文献   
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This article studies the relationship between students’ perceptions of teaching and learning in a multidisciplinary honours programme and their impact on graduate attributes acquisition. The study, conducted among 73 honours students in a Dutch research university, evaluates perceived improvement in graduate attributes through annually collected survey data pertaining to student motivation, perception of the teaching and learning environment, engagement in the programme and registered course marks. The evaluation study reveals that to the extent of the perceived development of graduate attributes, three factors play crucial roles: students’ performance motivation, the amount of teacher support in creative and critical thinking, and students’ inclination to approach the honours track as a learning community.  相似文献   
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Mainstreaming the exceptional child necessitates that regular and special teachers work much more closely today than in the past. The most important element for successful mainstreaming is effective communication (Schubert & Glick, 1981). This article describes the collaborative consultation model as one approach to attaining good, effective communication.  相似文献   
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The perceptions, knowledge, and opinions of 104 teachers of students with learning disabilities regarding medication used with their students were investigated. The students' doctors were perceived as the professionals primarily responsible for making the decision to have the student either placed on or taken off medication. The teachers indicated that global impressions and direct behavioral observations were used to assess the effects of medication but that they would prefer to use behavioral observations and rating scales. Hyperactivity and delusions/hallucinations were perceived as the problems most likely to lead to medication. Less than 15% of the teachers indicated that their professional preservice training had provided them with sufficient information on the use of medication for children with behavior problems, and less than 20% had a similar opinion regarding their inservice training on the same topic.  相似文献   
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