下一代GPS系统

目前,经常使用全球定位系统(GPS)的人数已达2000万,24颗"导航之星"(NavStar)组成的地球同步轨道卫星群(轨道高度为2万千米)随时为这些用户提供信号.阿富汗战争和伊拉克战争都证明了GPS系统不可或缺.     

The influence of exercise intensity on frontal electroencephalographic asymmetry and self-reported affect

The "feel better" effect of exercise has been well established, but the optimal intensity needed to elicit a positive affective response is controversial. In addition, the mechanisms underlying such a response are unclear To clarify these issues, female undergraduate students were monitored for electroencephalographic (EEG) and self-reported affective responses during the recovery period following rest, low, moderate, and high intensities of treadmill running, each lasting 30 min. Frontal EEG asymmetry and self-reported vigor scores following exercise at all three intensities were significantly elevated compared to those observed following rest. The results suggest that steady-state aerobic exercise bouts executed at varying intensities induce a similar affective response during the recovery period when assessed at both the behavioral and psychophysiological levels.     

Age-related Asynchrony of Knowledge and Action

Children's ability to act in accordance with rules was assessed in 2 experiments. Experiment I included 66 children, aged 31, 33.5, or 36 months, who performed 2 tasks. In a forced-choice, deductive sorting task, children were told 2 rules (if-then statements) and then required to use the rules to sort items. A knowledge task tested children's knowledge about which rule's antecedent condition held true for each item. Rules were either based on natural categories (e.g., vehicles vs. musical instruments) or ad hoc categories (e.g., things found inside the house vs. things found outside). Children in the 2 younger age groups performed better on the knowledge task than on the sorting task. The 36-month-olds performed equally well on both tasks. In Experiment 2, groups of 12 32.25-month-olds received either the knowledge task, the sorting task, or a mnemonically supported version of the sorting task. The group that received the knowledge task performed better than the other groups, which did not differ. This result undermines the possibility that differential performance on the knowledge and sorting tasks is due to a difference in memory demand. Taken together, the results of Experiments 1 and 2 imply a relatively rapid, age-related change culminating in the ability to execute systematically rules that require access to extant knowledge.     

In pursuit of becoming a senior coach: the learning culture for Australian Football League coaches

Background and Purpose: Given the turbulent and highly contested environment in which professional coaches work, a prime concern to coach developers is how coaches learn their craft. Understanding the learning and development of senior coaches (SCs) and assistant coaches (ACs) in the Australian Football League (AFL – the peak organisation for Australian Rules Football) is important to better develop the next generation of performance coaches. Hence the focus of this research was to examine the learning of SC and AC in the AFL. Fundamental to this research was an understanding that the AFL and each club within the league be regarded as learning organisations and workplaces with their own learning cultures where learning takes place. The purpose of this paper was to examine the learning culture for AFL coaches.

Method: Five SCs, 6 ACs, and 5 administrators (4 of whom were former coaches) at 11 of the 16 AFL clubs were recruited for the research project. First, demographic data were collected for each participant (e.g. age, playing and coaching experience, development and coach development activities). Second, all participants were involved in one semi-structured interview of between 45 and 90 minutes duration. An interpretative (hierarchical content) analysis of the interview data was conducted to identify key emergent themes.

Results: Learning was central to AFL coaches becoming a SC. Nevertheless, coaches reported a sense of isolation and a lack of support in developing their craft within their particular learning culture. These coaches developed a unique dynamic social network (DSN) that involved episodic contact with a number of respected confidantes often from diverse fields (used here in the Bourdieuian sense) in developing their coaching craft. Although there were some opportunities in their workplace, much of their learning was unmediated by others, underscoring the importance of their agentic engagement in limited workplace affordances.

Conclusion: The variety of people accessed for the purposes of learning (often beyond the immediate workplace) and the long time taken to establish networks of supporters meant that a new way of describing the social networks of AFL coaches was needed; DSN. However, despite the acknowledged utility of learning from others, all coaches reported some sense of isolation in their learning. The sense of isolation brought about by professional volatility in high-performance Australian Football offers an alternative view on Hodkinson, Biesta and James' attempt in overcoming dualisms in learning.     

Physiological profile of a professional boxer preparing for Title Bout: A case study

This study aimed to (1) profile a professional boxer (23 years and 80 kg) with boxing-specific, muscle function, aerobic capacity and body composition tests, and (2) quantify how these measures varied during an 8-week preparation phase leading to, and post a state-Title Bout fought in the 76.2-kg class. A series of boxing-specific and muscle function tests were completed on 11 occasions: 9 prior and twice after the bout, each separated by approximately 2 weeks. The boxing test included 36 maximal punches (9 of each: lead and rear straights, lead and rear hooks) to a punching integrator measuring forces and velocity. Muscle function tests included countermovement jump, drop-jumps, isometric mid-thigh pull and isometric bench-press. Body composition was assessed using skin-fold measurements on three occasions and one dual energy X-ray absorptiometry scan. Aerobic capacity was assessed using 2 VO₂ max tests. Leading up to the bout, performance decreased in isometric mid-thigh pull (8%), isometric bench-press (5%), countermovement jump (15%) and impact forces in 3 of 4 punches (4%–7%). Whereas measures of dynamic and isometric muscle function remained depressed or unchanged post competition, punching forces (6%–15%) and aerobic power (6%) increased. Data suggest the athlete may have super-compensated following rest as fatigue dissipated and further adaptation occurred.     

标记系统及学术文本处理的未来（一）

标记事务影响着学者们对思考与写作系统的采纳使用。程序性标记和表示性标记会阻碍这一进程的发展,描述性标记则通过简化机械性任务,让学者们将注意力集中于内容上的做法,以加快这一进程。     

Loneliness and Peer Relations in Young Children

Recent studies indicate that feelings of loneliness and social dissatisfaction can be reliably assessed with third- through sixth-grade children, and that children who are sociometrically rejected by their peers are significantly more lonely than other children. The present research was designed (a) to examine whether loneliness could be reliably assessed in a population younger than previously studied, (b) to learn whether young children who are poorly accepted by peers report elevated levels of loneliness and social dissatisfaction, (c) to assess whether young children understand the concept of loneliness, and (d) to examine the behavioral characteristics of lonely young children. Kindergarten and first-grade children (N = 440) responded to a questionnaire about feelings of loneliness and social dissatisfaction in school. A subset of children (N = 46) were individually interviewed to assess their understanding of loneliness. To assess sociometric status and behavior, peers were asked to respond to various sociometric measures and behavioral assessment items. Teachers also provided behavioral information about children using a newly developed instrument. Results indicated that nearly all children understood loneliness, that loneliness was reliably assessed in young children, and that poorly accepted children were more lonely than other children. In addition, children who reported the most loneliness were found to differ from others on several behavioral dimensions.     

Teaching about Cold Cases Experientially: Creating Meaningful Learning Experiences and Products

This paper discusses three separate educational projects which involved students working side-by-side with homicide investigators in an effort to conduct cold case investigations. Each project resulted in two different products, one for agency use and the other for public consumption. The cold case investigative reports produced for each case became part of the investigative file and are confidential documents. The video PSAs were for public consumption and were designed to provide additional exposure to the cases with the hope of generating productive tips. Each project was carried in collaboration with local Crime Stoppers programs, law enforcement agencies, and coroner’s offices.     

Adjunctive drinking during variable and random-interval food reinforcement schedules

Rats were trained to leverpress for food and subsequently exposed to either arithmetic series or random variable-interval reinforcement schedules. Adjunctive drinking developed in all subjects exposed to arithmetic variable-interval reinforcement, but did not develop in six of the eight animals trained on the random schedule. The results suggest that adjunctive drinking is the result of an interaction between the tendency of rats to drink after eating and the ability of locally low probabilities of reinforcement within schedules to induce conditioned behavioral states.