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W. A. HART 《Journal of Philosophy of Education》1993,27(1):17-27
The project of studying children in order to understand them, which lies at the heart of contemporary thinking about children and their education, is misconceived. It rests, jrst of all, upon a false belief that we can only come to know something properly by deliberately and systematically pursuing knowledge of it. Secondly, it offers a paradigm of knowing children which justifies parents and teachers in not giving themselves to children. By re-interpreting the problems that adults experience with children as technical, as arising from lack of information about them, it ignores the personal and moral dimension of adults' relations with children and thus further alienates them from one another. 相似文献
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A completely general three-dimensional dynamic model is presented for the motion of basketball shots that may contact the rim, the backboard, the bridge between the rim and board, and possibly the board and the bridge simultaneously. Non-linear ordinary differential equations with six degrees of freedom describe the ball angular velocity and ball centre position. The model includes radial ball compliance and damping and contains five sub-models: purely gravitational flight, and ball-rim, ball-bridge, ball-board, and ball-bridge-board contact. Each contact sub-model has both slipping and non-slipping motions. Switching between the sub-models depends on the reaction force at, and velocity of, the contact point. Although the model can be used to study shots from any point on the court, we here use it to study the sets of free throw release angle, velocity, angular velocity, and lateral deviation angle that result in success (capture), as well as underhand free throws and those using an under-inflated ball. Free throw shots with larger backspin, lower inflation pressures, and underhand release conditions are shown to result in larger capture percentages. 相似文献
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The relationship between peak height velocity and physical performance in youth soccer players 总被引:1,自引:1,他引:0
Philippaerts RM Vaeyens R Janssens M Van Renterghem B Matthys D Craen R Bourgois J Vrijens J Beunen G Malina RM 《Journal of sports sciences》2006,24(3):221-230
Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time. 相似文献
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This article discusses the changing relationships of authors and publishers, the current trends and challenges they face, and the direction of these relationships in the future. As the STM publishing industry finds itself in the midst of significant technological and economic changes, this article provides background to these changes and looks at the key elements, including open access business development, institutional repository trends, and emerging public financing policies in the future. 相似文献
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Females and youth are frequently described as "special" populations in football literature, but together these two populations outnumber male players. What makes females "special" is that they tend to eat less when training and competing than their male counterparts, leading to lower intakes of energy, carbohydrate, and some nutrients. Youth football players are special in regard to energy and nutrient requirements to promote growth and development, as well as to fuel sport. There is limited research on the dietary habits of these two populations, but the available literature suggests that many female and youth players need to increase carbohydrate intake, increase fluid intake, and develop dietary habits to sustain the demands of training and competition. 相似文献