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1.
The purpose of this study was to compare measures of body size in two samples of youth baseball players with normative data from the United States National Center for Health Statistics (NCHS) growth charts. One sample of youth baseball players participated in a local little league. The second sample of youth baseball players were members of eight of the twelve teams participating in the 1995 Dixie Youth World Series. Normative data for the United States (NCHS) were used as comparative data. Two trained anthropometrists measured standing height, sitting height, lower limb height, upper limb length, arm girth, calf girth, tricep skinfold, and abdomen skinfold on all participants. In both samples, pitchers, short stops, and first basemen were a more highly skilled group and exhibited larger body size (greater standing height, sitting height, lower limb height, upper limb length) than children who played at other positions. The standing height of local little league players was similar to the median of reference data at ages 7, 8, and 9 years. The standing height and weight of skilled players in both samples approximated the 75th percentile for standing height and weight at ages 10, 11, 12, and 13 years. The results suggest that baseball players exhibit larger body size than the normal population at young ages. Body size may be an important criterion used by coaches to select and assign young players to certain positions. 相似文献
2.
Shawn L. Spurgeon 《Journal of College Counseling》2009,12(1):33-43
African American male students (N = 203) attending a historically Black college or university (HBCU) and a predominantly White institution (PWI) participated in a study to determine differences in wellness. HBCU students scored significantly higher than did PWI students on Friendship, Love, Sense of Control, and Gender Identity. PWI students scored significantly higher than did HBCU students on Sense of Worth. Implications and future research directions are suggested. 相似文献
3.
Stuart JH Biddle CK John Wang Nikos LD Chatzisarantis 《Journal of sports sciences》2013,31(12):973-989
Three studies are reported of children and youth aged 11–19 years (n?=?3478) examining the nature of beliefs about athletic ability. Drawing on related research in academic, moral and stereotyping domains, development of a psychometric instrument assessing athletic ability beliefs is detailed. Support was found for a multidimensional hierarchical structure that is invariant across age and gender. Confirmatory factor analysis revealed a structure comprising two higher-order factors of entity and incremental beliefs underpinned by beliefs that athletic ability is stable and a gift (entity), and is open to improvement and can be developed through learning (incremental). Incremental beliefs, indirectly through a task goal orientation, and entity beliefs directly, predicted self-reported amotivation towards physical education and sport. On the other hand, enjoyment of physical activity in youth was predicted directly by task orientation and incremental beliefs. Predictions concerning the moderating role of perceived competence were not supported. Our findings highlight the importance of ability beliefs and goals in understanding the determinants of physical activity in children and youth. 相似文献
4.
From original data at age 13 years on 386 North American females (201 black and 185 white), statistics are presented for 10 somatic variables. The 2 ethnic groups yield similar means for standing height, arm girth, and leg girth; the black females, contrasted with their white peers, are shorter in sitting height, longer in lower limb height, and narrower in hip width. The Columbia subjects are compared with black and white females studied in North America several decades ago, and with black and white females studied recently in other parts of North America and in Australia, Europe, Africa, and the Lesser Antilles. 相似文献
5.
AN Pisarchik R Jaimes-Reátegui C Rodríguez-Flores JH García-López G Huerta-Cuellar FJ Martín-Pasquín 《Journal of The Franklin Institute》2021,358(4):2561-2575
Extreme multistability is the coexistence of a large number of attractors which can be reached by varying initial conditions. In this paper we show how this fascinating phenomenon can be used for secure communication. The main advantage of the communication system based on extreme multistability over a conventional chaos-based communication system is its exceptionally high security. The proposed system consists of two identical six-order oscillators; one in the transmitter and another one in the receiver, each exhibiting the coexistence of a large number of chaotic attractors. The oscillators are synchronized using a private channel through one of the system variables, while the information is transmitted via a public channel through another variable. The information is encrypted by varying the initial condition of one of the state variables in the transmitter using a chaotic map, adhering message packages in a staggered form to the coexisting attractors within the same time series of another state variable, which leads to switching among the coexisting chaotic attractors. To ensure communication security, the duration of the packages is shorter than synchronization time, so that synchronization attacks are ineffective. 相似文献
6.
医学院校课程整合的经验教训:学生、课程负责人与改革领导者的观点 总被引：1，自引：0，他引：1
美国医学院校的课程整合改革方兴未艾.加州大学旧金山分校医学院从2001级新生开始对课程体系进行大幅调整,本研究调查了该校参与改革的不同群体,包括教育改革的领导者、受到直接影响的学生、新建课程的负责人等对课程改革的态度,了解其对课程整合实施一年内的成绩和挑战的看法.结果表明,他们对跨学科教学、跨学科系室协作、课程关联的建立、课程内容的排序及框架构建等四个主题有相同的看法,也有不小的分歧. 相似文献
7.
Karen E. French John H. Spurgeon Michael E. Nevett 《Research quarterly for exercise and sport》2013,84(3):179-188
Abstract The purpose of this study was to compare measures of body size in two samples of youth baseball players with normative data from the United States National Center for Health Statistics (NCHS) growth charts. One sample of youth baseball players participated in a local little league. The second sample of youth baseball players were members of eight of the twelve teams participating in the 1995 Dixie Youth World Series. Normative data for the United States (NCHS) were used as comparative data. Two trained anthropometrists measured standing height, sitting height, lower limb height, upper limb length, arm girth, calf girth, tricep skinfold, and abdomen skinfold on all participants. In both samples, pitchers, short stops, and first basemen were a more highly skilled group and exhibited larger body size (greater standing height, sitting height, lower limb height, upper limb length) than children who played at other positions. The standing height of local little league players was similar to the median of reference data at ages 7, 8, and 9 years. The standing height and weight of skilled players in both samples approximated the 75th percentile for standing height and weight at ages 10, 11, 12, and 13 years. The results suggest that baseball players exhibit larger body size than the normal population at young ages. Body size may be an important criterion used by coaches to select and assign young players to certain positions. 相似文献
8.
Karen E. French PhD John H. Spurgeon Michael E. Nevett 《Research quarterly for exercise and sport》2013,84(3):194-201
Abstract Previous research has shown that experts exhibit superior response selection and skill execution during performance in youth sport. The purpose of this study was to examine differences in cognitive and skill execution components of game performance in young baseball players (N = 159) with, varying levels of expertise. Three levels of expertise (low-, average-, and high-skilled players) were identified at each age level (7, 8, 9, and 10 years of age). Game performance was videotaped, and measures of skill execution (throwing accuracy, throwing force, fielding, catching, batting average, and batting contact) and cognitive components (positioning, decisions) were developed from observational analysis. The results indicated that baseball skill execution during game play maximally discriminated expertise levels. 相似文献
9.
A sliding mode observer in the presence of sampled output information and its application to robust fault reconstruction is studied. The observer is designed by using the delayed continuous-time representation of the sampled-data system, for which sufficient conditions are given in the form of linear matrix inequalities (LMIs) to guarantee the ultimate boundedness of the error dynamics. Though an ideal sliding motion cannot be achieved in the observer when the outputs are sampled, ultimately bounded solutions can be obtained provided the sampling frequency is fast enough. The bound on the solution is proportional to the sampling interval and the magnitude of the switching gain. The proposed observer design is applied to the problem of fault reconstruction under sampled outputs and system uncertainties. It is shown that actuator or sensor faults can be reconstructed reliably from the output error dynamics. An example of observer design for an inverted pendulum system is used to demonstrate the merit of the proposed methodology compared to existing sliding mode observer design approaches. 相似文献
10.
L. DiAnne Borders Kelly L. Wester Darcy Haag Granello Catherine Y. Chang Danica G. Hays Jennifer Pepperell Shawn L. Spurgeon 《Counselor Education & Supervision》2012,51(3):162-175
The authors describe guidelines endorsed by the Association for Counselor Education and Supervision for research mentorship, including characteristics of mentors and mentees. Suggestions for implementing the guidelines at the individual, program, institution, and professional levels are focused on enhancing mentoring relationships as well as mentees’ research quality and productivity. Research on research mentoring, based on the guidelines, is encouraged. 相似文献