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A semi-structured interview was used to enquire into the knowledge of models and modelling held by a total sample of 39 Brazilian science teachers working in 'fundamental' (ages 6-14 years) and 'medium' (ages 15-17 years) schools, student teachers, and university teachers. This paper focuses on their perceptions of the role of models in science teaching. The teachers' ideas are organized in three groups: the status and value of models; the influences that inform the translation of these general ideas into classroom practice; and how they respond to the outcomes of students' modelling activities. The teachers interviewed generally showed an awareness of the value of models in the learning of science but not of their value in learning about science. They were also uncertain of the relationship that could exist in the classroom between various types of models. Modelling, as an activity by students, whilst praised in theory, would not seem to be widely practised. Where practised, the outcomes are by no means always treated with that integrity that learning about science would call for. 相似文献
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Malachy P McHugh Timothy F Tyler Scott C Greenberg Gilbert W Gleim 《Journal of sports sciences》2002,20(2):83-91
Previous studies analysing electromyograms (EMGs) from indwelling electrodes have indicated that fast-twitch motor units are selectively recruited for low-intensity eccentric contractions. The aim of this study was to compare the frequency content of surface EMGs from quadriceps muscles during eccentric and concentric contractions at various contraction intensities. Electromyograms were recorded from the rectus femoris, vastus lateralis and vastus medialis muscles of 10 men during isokinetic (1.05 rad x s(-1)) eccentric and concentric knee extension contractions at 25%, 50%, 75% and 100% of maximal voluntary contraction (MVC) for each contraction mode. Additionally, isometric contractions (70 degrees) were performed at each intensity. The mean frequency and root mean square (RMS) of the surface EMG were computed. Mean frequency was higher for eccentric than concentric contractions at 25% (P < 0.01), 50% (P < 0.01) and 75% (P < 0.05) but not at 100% MVC. It increased with increasing contraction intensity for isometric (P < 0.001) and concentric (P < 0.01) contractions but not for eccentric contractions (P = 0.27). The EMG amplitude (RMS) increased with increasing contraction intensity similarly in each contraction mode (P < 0.0001). Higher mean frequencies for eccentric than concentric contractions at submaximal contraction intensities is consistent with more fast-twitch motor units being active during eccentric contractions. 相似文献
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Larsen GE George JD Alexander JL Fellingham GW Aldana SG Parcell AC 《Research quarterly for exercise and sport》2002,73(1):66-72
The purpose of this study was to develop a submaximal, 1.5-mile endurance test for college-aged students using walking, jogging, or running exercise. College students (N = 101: 52 men, 47 women), ages 18-26years, successfully completed the 1.5-mile test twice, and a maximal graded exercise test. Participants were instructed to achieve a "somewhat hard" exercise intensity (rating of perceived exertion = 13) and maintain a steady pace throughout each 1.5-mile test. Multiple linear regression generated the following prediction equation: VO2 max = 65.404 + 7.707 x gender (1 = male; 0 =female) - 0.159 x body mass (kg) - 0.843 x elapsed exercise time (min; walking, jogging orrunning). This equation shows acceptable validity (R = .86, SEE = 3.37 ml x kg(-1) min(-1)) similar to the accuracy of comparable field tests, and reliability (ICC = .93) is also comparable to similar models. The statistical shrinkage is minimal (R(press) = 0.85, SEE(press) = 3.51 ml x kg(-) x min(-1)); hence, it should provide comparable results when applied to other similar samples. A regression model (R =.90, and SEE = 2.87 ml x kg(-1) min(-1)) including exercise heart rate was also developed: VO2 max = 100.162 +/- 7.301 x gender(1 = male; 0 =female) - 0.164 x body mass (kg) - 1.273 x elapsed exercise time -0.156 x exercise heart rate, for those who have access to electronic heart rate monitors. This submaximal 1.5-mile test accurately predicts maximal oxygen uptake (VO2max) without measuring heart rate and is similar to the 1.5-mile run in that it allowsfor mass testing and requires only a flat, measured distance and a stopwatch. Further, it can accommodate a wide range of fitness levels (from walkers to runners). 相似文献
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‘It's important that we remember the past is not just dry facts and statistics but also the detailed lives of real people. SAPPHIRE aims to give a voice to these lives.’ The Scottish Archive of Print and Publishing History Records (SAPPHIRE), an initiative with Napier University as lead and Queen Margaret University College as main collaborative partner, is an oral history project which aims to record the social, economic and cultural heritage of the Scottish printing and publishing industry in the 20th century. Undertaken in partnership with a number of Scottish organizations, its results are providing a better understanding of an important and overlooked part of Scotland's heritage. Outcomes of the project include a permanent oral history archive stored at the Edward Clark Collection at Napier University, and exhibitions and publications on the history of the printing and publishing industry. The development and current activities of SAPPHIRE are described and reviewed. 相似文献