Perception of kinematic characteristics of tennis strokes for anticipating stroke type and direction     

Shim J  Les Carlton G  Kwon YH 《Research quarterly for exercise and sport》2006,77(3):326-339

The purpose of this study was to determine the sources of visual information used by highly skilled tennis players in anticipating their opponent's shots. In Experiment 1, motion analysis of the strokes showed that the relative motion between the racquet and forearm was different between the ground strokes and lobs, but there were no reliable kinematic differences when shot direction was varied. In Experiment 2, 12 skilled tennis players observed the opponent hitting strokes in a normal video or in a point-light display with different segments occluded. Players' anticipation accuracy was not degraded by the use of the point-light display. Occluding the racquet and forearm significantly reduced the participant's ability to determine the type of stroke produced.  相似文献   

Against the current: A grounded theory study on the estrangement experiences of a select group of Filipino gay older persons     

Allan B. de Guzman  Les Paul Valdez  Maverick B. Orpiana  Nikki Angela F. Orantia  Patrick Van E. Oledan  Karla Monica Cenido 《Educational gerontology》2017,43(7):329-340

According to Healthy People (2011), in order to understand the health concerns of the Lesbian, Gay, Bisexual, and Transgender (LGBT), the oppression and discrimination that they have faced must be scrutinized. Among the many issues they face, their estrangement experiences are one of the most understudied. However, little is known about how it is experienced by the gay elderly population, hence, this investigation. This grounded theory purports to describe the process by which estrangement is experienced among the Filipino gay older adults. Strauss and Corbin’s Grounded Theory (1990) design was utilized. A total of 10 gay older persons were purposively chosen to participate in semi-structured interviews. Field texts were subjected to thematic analysis involving open, axial, and selective coding. The study generated The Sailing Model of Estrangement. Remarkably, three phases relative to estrangement emerged, namely: sequestering, striving, and surviving. Primarily, the sequestering phase involves the gay persons’ need to express self, search for acceptance, and its subsequent reactions. The striving phase typifies the struggle in dealing with estrangement leading to either feelings of depression, remorse and shame or positivity, hopefulness, and motivation. Finally, in the surviving phase, gay persons may either feel contented and fulfilled or sad, lonely, and remorseful as they acquiesce aging with estrangement. Findings of the study offer an understanding of how Filipino gay older adults employ coping strategies in response to estrangement.  相似文献   

The development of pattern recognition ability in children     

Les Sternberg  Paul Larson 《Contemporary educational psychology》1976,1(2):146-156

Pattern recognition development was studied in high and low ability preschool, kindergarten, and first-grade youngsters. Pattern recognition was assessed by the administration of 96 pattern tasks which measured the ability of a youngster to find: (a) duplicate patterns and elements to a model; (b) the opposite pattern to a model; and (c) duplicate patterns but different elements than in the model. Aside from main effects for grade level, ability level, and pattern task, a significant three-way interaction was noted. This interaction was analyzed in terms of its component simple effects. The implication of these simple interaction effects for Piagetian theory and educational practice were discussed.  相似文献   

Comparing the pre- and post-impact ball and racquet kinematics of elite tennis players' first and second serves: a preliminary study   总被引：1，自引：0，他引：1  

Chow JW  Carlton LG  Lim YT  Chae WS  Shim JH  Kuenster AF  Kokubun K 《Journal of sports sciences》2003,21(7):529-537

The aim of this study was to compare the pre- and post-impact three-dimensional kinematics of the ball and racquet during first and second serves performed by elite tennis players. Data were collected from four male and four female right-handed professional players during competition using two high-speed cameras (200 Hz). For each player, one first serve and one second serve from the 'deuce' or right service court that landed within the specified target area were analysed. To test for significant differences between the first and second serves, Wilcoxon tests (P < or = 0.05) were performed on selected parameters. The results indicate that the ball travelled forward and to the left during the flight phase of the toss in all but one trial. The average pre-impact ball forward location for the first serve was significantly more in front and had a higher associated forward ball velocity than the corresponding values for the second serve. On average, the decrease in post-impact ball speed from the first to the second serve was 24.1%. No significant differences between the first and second serves were found in the pre-impact racquet head speed and orientation, which was represented as a unit vector perpendicular to the racquet face. The major adjustments made by the players when going from the first to second serve were a decrease in pre-impact ball forward location (P < or = 0.01) and an increase in the pre-impact racquet vertical and lateral velocities (both P < or = 0.05). This implies that the players tossed the ball closer to the body and imparted topspin and sidespin on the ball by changing the racquet vertical and lateral velocities when going from the first to the second serve.  相似文献   

Use of machine-readable databases to support a large SDI service     

Donald T. Hawkins 《Information processing & management》1985,21(3):187-204

The current awareness [or selective dissemination of information (SDI)] services of AT&T Bell Laboratories are described. Several bulletins announcing over 80,000 externally published items/year are issued at regular intervals and sent to about 6100 subscribers. Production is done by the BELLPAR (Bell Laboratories Publication, Alerting, and Retrieval) system, which processes four commercial machine-readable databases and prepares camera-ready bulletin copy. A photocopy service processing some 10,000 requests/month provides document delivery for items announced in the bulletins. Subscribers may order photocopies electronically if they wish. A “captive” journal collection supports the copying operation; non-journal articles, such as conference proceedings and technical reports, are ordered from external suppliers. Improvements in the SDI service include electronic bulletins, more focused bulletins and additional databases as input.  相似文献   

The dynamical theory of alternating current machinery and the problem of the stability of power systems     

Wyatt Hawkins Ingram 《Journal of The Franklin Institute》1930,210(3):327-343

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The bourdon pressure gauge     

John T. Hawkins 《Journal of The Franklin Institute》1866,81(2):73-76

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A Fresh Theoretical Perspective on Practice‐Led Research          下载免费PDF全文

Barbara Hawkins  Brett Wilson 《The International Journal of Art & Design Education》2017,36(1):82-91

Practice‐led research in art and design has now come of age and can take its place alongside other forms of research at the academic ‘high table’. It no longer needs to be treated with ‘special consideration’ as a new form of intellectual enquiry. The research craft developed by those involved in practice‐led research admits them to a broader community of practice engaged in questioning the conceptual basis of how we perceive and make sense of the world around us. The objective/subjective divide that preoccupied an earlier generation of academics has eventually been replaced by a more nuanced epistemological framework able to embrace PhDs that include non‐textual artefacts as part of their exposition. An increasing number of academic institutions around the world have taken up the debate and now participate in practice‐led research programmes. However, for early‐career researchers in these fields there are still many hurdles to overcome, some of which are unique to this form of endeavour, as we outline. This article has been developed from a series of seminars and workshops presented by the authors to early‐career practice‐led researchers as part of their Project Dialogue programme which seeks greater engagement between the arts and sciences.  相似文献   

Exploring inclusive pedagogy     

Lani Florian  Kristine Black‐Hawkins 《British Educational Research Journal》2011,37(5):813-828

This paper reports on a study designed to examine teachers' craft knowledge of their practice of ‘inclusion’ in terms of what they do, why and how. The research approach offers an important alternative to studies of students with ‘additional needs’ and the search to articulate the specialist knowledge and skill required to teach them. Through classroom observations and interviews with 11 teachers of students across the full age range in two Scottish primary schools, we investigated how teachers make meaning of the concept of inclusion in their practice by exploring theoretical assumptions drawn from the literature about inclusive pedagogy. The analysis enabled us to identify practical examples of inclusive pedagogy that met the standard of extending what is generally available to everybody, as opposed to providing for all by differentiating for some. Examples of the inclusive pedagogical approach are provided.  相似文献   

Endurance training adherence in elite junior netball athletes: a test of the theory of planned behaviour and a revised theory of planned behaviour     

Palmer CL  Burwitz L  Dyer AN  Spray CM 《Journal of sports sciences》2005,23(3):277-288

This study examined the utility of Ajzen's (1985) theory of planned behaviour and Maddux's (1993) revised theory of planned behaviour to predict endurance training intentions and adherence of elite junior netball athletes. One hundred and fifteen athletes from the England Netball World Class Start Programme were assessed on constructs central to the predictions of the two theories. Adherence to a recommended endurance training programme was recorded in self-report diaries across a 9-week period. Validity for the diaries was supported by significant correlations (P < 0.001) with recalls across 7 days and 9 weeks. Adherence was moderate and variable between athletes (mean = 66.05, s = 25.75%). Two separate path analyses were conducted to examine the predictions of the theories. Goodness-of-fit indices suggested acceptable fit of the data to the models. Analyses showed that attitude towards the new behaviour, subjective norms and perceived behavioural control predicted training intentions. The relationship between intention and adherence was weak. The present results suggest that the constructs of the theory of planned behaviour offer some insight into the explanation of intentions to follow an endurance training programme. Constructs unique to the revised theory of planned behaviour did not significantly predict training intentions or behaviour. Implications for practitioners working with team sport performers are provided.  相似文献