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The use of cycle ergometers with strain gauges bonded on to the cranks enables the evaluation of strength, velocity and power.
However, the torque measured at the end of downstroke is higher at high velocity than at medium velocity in contradiction
with the force–velocity relationship. Kinematic data were collected with a camera during sprints on a Lode ergometer with
strain gauges. Leg mechanical energy (E
Leg) and its derivative (dE
Leg/dt) were calculated from the sum of the kinetic and potential energies. The opposition of P
ext (output at crank level) and dE
Leg/dt before bottom dead centre suggested a transformation of E
Leg into external work, explaining the higher torque at the end of downstroke at peak velocity. Another explanation is that the
leg muscles worked on different parts of their torque–angle relationships as the phase between knee and ankle angles was different
at low and high cycling frequencies. Musculo-skeletal net power output (algebraic sum of P
ext and dE
Leg/dt) indicated that musculo-skeletal structures participated in the upward movement, whereas P
ext was negative. 相似文献
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This paper describes the design, development and evaluation of an experimental two‐way video teletraining (VTT) system consisting of two classrooms equipped with audio and video equipment and linked by a land line to enable two‐way audio/video communication. A US Navy instructor delivered instruction in person to the originating classroom and electronically to the remote classroom. Findings were that student attitudes and performance on examinations were comparable in originating and remote classrooms. Students at the remote classroom were more likely to comment on deficiencies of the VTT system and were particularly sensitive to audio problems. Instructor acceptance of the VTT system was high. Cost analysis indicated that using the VTT system was more costly than sending an instructor to a remote site but that VTT can be less cosdy than sending students to the instructor.
The research described was performed under the sponsorship of the Office of Naval Technology. The opinions expressed in this paper are those of the authors, are not official, and do not necessarily reflect the views of the Navy department. 相似文献
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Three- to 5-year-old (N = 61) religiously schooled preschoolers received theory-of-mind (ToM) tasks about the mental states of ordinary humans and agents with exceptional perceptual or mental capacities. Consistent with an anthropomorphism hypothesis, children beginning to appreciate limitations of human minds (e.g., ignorance) attributed those limits to God. Only 5-year-olds differentiated between humans' fallible minds and God's less fallible mind. Unlike secularly schooled children, religiously schooled 4-year-olds did appreciate another agent's less fallible mental abilities when instructed and reminded about those abilities. Among children who understood ordinary humans' mental fallibilities, knowledge of God predicted attributions of correct epistemic states to extraordinary agents. Results suggest that, at a certain point in ToM development, sociocultural input can facilitate an appreciation for extraordinary minds. 相似文献
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Improving K-12 pedagogy via a Cloud designed for education 总被引:1,自引:0,他引:1
Sarah Stein Jennifer Ware Johanne Laboy Henry E. Schaffer 《International Journal of Information Management》2013
Cloud computing offers an opportunity to improve K-12 pedagogy with services tailored to teachers’ needs in individual classrooms. The Cloud can deliver services such as remote access to learning tools in a cost effective manner to school systems struggling with reductions in local and state funding. This article explores the distinct ways that a Cloud designed specifically for education can be applied to K-12 education's academic mission. It uses observations from a case study in North Carolina rural high schools using an educational Cloud called the Virtual Computing Lab to access dynamic geometry and algebra software. 相似文献