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Drawings of familiar objects arranged to suggest more general wholes (e.g., a beast made of pieces of fruit) were presented to 128 children aged 3-12 years, using 4 exposure durations. The ability to see both parts and wholes together improved with age, confirming earlier studies. In addition, the results suggest that limiting viewing time affects the ability to see both parts and wholes together (in a sequential, nonintegrated fashion) more in young children than in older children. The results further suggest that for younger children duration does not affect the ability to see parts and wholes in a hierarchical relationship. These results are interpreted as suggesting that at least 2 different processes mediate part-whole perception in children. 相似文献
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Thomas Whiteside John Dizer Jr. Roy Harley Lewis Linda S. Hubbard 《Communication Booknotes Quarterly》2013,44(9-10)
Thomas Whiteside, THE BLOCKBUSTER COMPLEX: CONGLOMERATES, SHOW BUSINESS, AND BOOK PUBLISHING (MiddletOwn, Conn., 1981---$12.95) John Dizer, Jr., TOM SWIFT & COMPANY: "BOY'S BOOKS" BY STRATEMEYER AND OTHERS (McFarland & Co. Inc., Box 611, Jefferson, N.C. 28640---$17.95) Roy Harley Lewis, THE BOOK BROWSER'S GUIDE TO SECONDHAND AND ANTIQUARIAN BOOKSHOPS (North Pomfret, Vt.: David & Charles, 1982---$23.50) Linda S. Hubbard, ed. BOOK PUBLISHERS DIRECTORY (Detroit; Gale Research, 1981---$160) 相似文献
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Wayne Spratford David Whiteside Bruce Elliott Marc Portus Nicholas Brown Jacqueline Alderson 《Journal of sports sciences》2018,36(6):651-659
Spin bowling plays a fundamental role within the game of cricket yet little is known about the initial ball kinematics in elite and pathway spin bowlers or their relationship to performance. Therefore, the purpose of this study was to record three-dimensional ball kinematics in a large and truly high level cohort of elite and pathway finger-spin (FS) and wrist-spin (WS) bowlers, identifying potential performance measures that can be subsequently used in future research. A 22-camera Vicon motion analysis system captured retro-reflective markers placed on the seam (static) and ball (dynamic) to quantify ball kinematics in 36 FS (12 elite and 24 pathway) and 20 WS (eight elite and 12 pathway) bowlers. Results indicated that FS bowlers delivered the ball with an increased axis of rotation elevation, while wrist-spin bowlers placed greater amounts of revolutions on the ball. It also highlighted that ball release (BR) velocity, revolutions and velocity/revolution index scores for both groups and seam stability for FS bowlers, and seam azimuth angle and spin axis elevation angle for WS bowlers, were discriminators of playing level. As such these variables could be used as indicators of performance (i.e. performance measures) in future research. 相似文献
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Effect of skill decomposition on racket and ball kinematics of the elite junior tennis serve 总被引：1，自引：0，他引：1
Reid M Whiteside D Elliott B 《Sports biomechanics / International Society of Biomechanics in Sports》2010,9(4):296-303
Whole body kinematics of the tennis serve have been reported extensively in the literature, yet comparatively less information exists regarding the kinematic characteristics of the swing and toss. In attempting to develop consistency in placement of the toss and racket trajectory, coaches will often decompose the serve and practice it in separate parts. A 22-camera VICON MX motion analysis system, operating at 250 Hz, captured racket, ball and hand kinematics of the serves of five elite junior players under three conditions. The conditions were flat first serves (FS) directed to a 1 x 1 m target bordering the 'T' of the deuce service box, a ball toss (BT) in isolation and a free swing (SW) in isolation. Players were instructed to perform BT and SW as in the FS. Paired t-tests assessed within-group differences in hand, racket and ball kinematics between the discrete skill and the two decomposed conditions. Vertical displacement of the ball at its zenith increased significantly during BT compared with the FS and temporal associations between racket and ball motion during the FS (r = 0.861) were affected during task decomposition. This study questions the pervasive use of task decomposition in the development of the tennis serve. 相似文献
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This study sought to determine the features of an ideal serve in men’s professional tennis. A total of 25,680 first serves executed by 151 male tennis players during Australian Open competition were classified as either aces or returned into play. Spatiotemporal (impact location, speed, projection angles, landing location and relative player locations) and contextual (score) features of each serve were extracted from Hawk-Eye data and used to construct a classification tree model (with decision rules) that predicted serve outcome. k-means clustering was applied to the landing locations to quantify optimal landing locations for aces. The classification tree revealed that (1) serve directionality, relative to the returner; (2) the ball’s landing proximity to the nearest service box line and (3) serve speed classified aces with an accuracy of 87.02%. Hitting aces appeared more contingent on accuracy than speed, with serves directed >5.88° from the returner and landing <15.27 cm from a service box line most indicative of an ace. k-means clustering revealed four distinct locations (≈0.73 m wide × 2.35 m deep) in the corners of the service box that corresponded to aces. These landing locations provide empirically derived target locations for players to adhere to during practice and competition. 相似文献
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Georgia Giblin David Whiteside Machar Reid 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):23-33
The serve is considered amongst the most important strokes in tennis. Not surprisingly, the development of a mechanically consistent and proficient serve is paramount. Correspondingly, drills that involve players serving with their eyes closed are thought to promote mechanical consistency. The purpose of this study was therefore to contrast the effect of the removal of visual feedback on ball and racket kinematics in the serve. A 10-camera 500-Hz VICON MX motion analysis system recorded the service actions of eight elite young players as they performed three serves with eyes open and three serves with eyes closed. Removal of vision resulted in considerable differences in both racket and ball kinematics, with players failing to make contact on 16 of 24 serves. Temporally, the preparation phase was significantly shorter with eyes closed. Spatially, the ball was located 6.5 cm further to the right at zenith, and 13 cm higher at impact with eyes closed. These results highlight that the serve is not entirely pre-programmable, and that visual feedback is critical to the spatiotemporal regulation of the serve. In turn, coaches need to be aware of the implications of modifying visual feedback in serve, and ensure that the consequence is congruent with their intent. 相似文献
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This research uses a content analysis to explore how male and female high school athletes are framed. In analyzing basketball coverage from 121 unique newspapers, results show that although boys received the bulk of the coverage, the gap in parity is much smaller compared to prior research. Furthermore, girls were generally not framed as overtly feminine. Still, the coverage also reflects lingering commonsense assumptions about gender, most notably in reference to the athletic body. The authors discuss the potential of high school sports coverage to challenge normative understandings of gender and sports and to consider the role community journalism standards may play in the construction of equitable and just interscholastic sports coverage. 相似文献