Impact of a statewide home visiting program to prevent child abuse

OBJECTIVES: To assess the impact of a voluntary, paraprofessional home visiting program in preventing child maltreatment and reducing the multiple, malleable psychosocial risks for maltreatment for which families had been targeted. METHODS: This collaborative, experimental study focused on 6 Healthy Families Alaska (HFAK) programs; 325 families were enrolled in 2000-2001, randomized to intervention and control groups, and interviewed to measure baseline attributes. Follow-up data were collected when children were 2 years old (85% follow-up rate). Outcomes included maltreatment reports, measures of potential maltreatment and parental risks, for example, poor mental health, substance use, and partner violence. HFAK records were reviewed to measure home visiting services. Home visitors were surveyed to measure perceived effectiveness and training adequacy. RESULTS: Parental risks were common at baseline, and one-sixth of families had a substantiated child protective services report in the child's first 2 years of life. There was no overall program effect on maltreatment reports, and most measures of potential maltreatment. Home visited mothers reported using mild forms of physical discipline less often than control mothers. The groups were similar in their use of more severe forms of physical discipline. There was no program impact on parental risks. There was no impact on outcomes for families with a 'high dose' of home visiting. Home visitors often failed to address parental risks and seldom linked families with community resources. Contradictions in the model compromised effectiveness. CONCLUSIONS: The program did not prevent child maltreatment, nor reduce the parental risks that had made families eligible for service. Research is needed to develop and test strategies to improve the effectiveness of home visiting.     

中国留学生在美国的师生互动压力：以美国某大学为例

本文从师生互动的维度解析了中国留学生在美国大学中的学业压力因素.四种因素构成了中国学生和美国教授互动的主要压力因素:语言功力不足、缺少对学业的自治和自主引领、言语表达的被动性、交流模式的非直接性.中国学生的压力是中关两种文化模式和教育模式碰撞合力作用的结果.这为反思中国教育的问题提供了有效切入点.本文从英语语言教育和转变人才培养观念两个方面为中国教育提出了相应的建议.并指出中国学生应进行"深层结构性社会文化转化",充分适应美国大学的学术文化,与美国教授形成良性互动,最终减缓跨文化所带来的压力.     

Effects of dynamic upper-body exercise on lower-limb isometric endurance

Following preliminary indications that in some individuals arm exercise enhanced rather than reduced simultaneous leg endurance, ten young men and women performed three forms of intermittent work to volitional exhaustion, under duty cycles of 45 s work, 15 s rest. The protocols were as follows: (A) knee extensions at 30% maximum voluntary contraction (MVC); (B) 30% MVC knee extensions combined with arm cranking at 130% of their own lactate threshold; (C) combined 30% MVC knee extensions and arm cranking at 20% of their own lactate threshold. Heart rate, oxygen uptake (VO(2)), and blood lactate concentration were among the variables recorded throughout. All physiological indicators of demand were substantially higher in protocol B than in protocols A or C [heart rate: (A) 154 beats . min(-1), (B) 171 beats . min(-1), (C) 150 beats . min(-1); VO(2): (A) 11.9 ml . kg(-1) . min(-1), (B) 21.7 ml . kg(-1) . min(-1), (C) 14.2 ml . kg(-1) . min(-1); blood lactate concentration: (A) 3.3 mmol . l(-1), (B) 5.1 mmol . l(-1), (C) 2.8 mmol . l(-1)], yet there were no significant differences (P > 0.05) in the endurance times between the three conditions [(A) 11.43 min, (B) 11.1 min, (C) 10.57 min] and seven participants endured longest in protocol B. Results from protocol (C) cast doubt on explanations in terms of psychological distraction. We suggest that lactic acid produced by the arms is shuttled to the legs and acts there either as a supplementary fuel source or as an antagonist to the depressing effects of increased potassium concentration.     

The performance environment of the England youth soccer teams

In the present study, we examined the performance environment of the England youth soccer teams. Using a semi-structured protocol with a prospective sample, national coaches (n = 6), sport scientists (n = 3), and players (n = 4) were interviewed directly following international tournaments about the factors that positively and negatively influenced performance. Qualitative content analysis revealed the following factors as major positive influences on performance: adhering to a consistent tournament strategy, player understanding, strong team cohesion, organized entertainment activities, detailed knowledge of opposition, an effective physical rest/recovery strategy, and previous tournament experience. Major factors perceived to have negatively influenced performance included: over-coaching, player boredom, player anxiety, physical superiority of the opposition, physical fatigue over the tournament, problems sleeping, and lack of information on the opposition. Eight overall dimensions emerged to describe the performance environment: planning and organization, physical environment, tactical factors, development and performance philosophy, psychological factors, physical factors, social factors, and coaching. The findings support recent work that suggests the performance environment is multifaceted, with performance being contingent upon a broad range of interacting factors that go beyond the traditional psychosocial and physical domains.     

Effects of rest interval during high-repetition resistance training on strength, aerobic fitness, and repeated-sprint ability

The effect of altering the rest period on adaptations to high-repetition resistance training is not well known. Eighteen active females were matched according to leg strength and repeated-sprint ability and randomly allocated to one of two groups. One group performed resistance training with 20-s rest intervals between sets, while the other group employed 80-s rest intervals between sets. Both groups performed the same total training volume and load. Each group trained 3 days a week for 5 weeks [15- to 20-repetition maximum (RM), 2 - 5 sets]. Repeated-sprint ability (5x6-s maximal cycle sprints), 3-RM leg press strength, and anthropometry were determined before and after each training programme. There was a greater improvement in repeated-sprint ability after training with 20-s rest intervals (12.5%) than after training with 80-s rest intervals (5.4%) (P = 0.030). In contrast, there were greater improvements in strength after training with 80-s rest intervals (45.9%) than after training with 20-s rest intervals (19.6%) (P = 0.010). There were no changes in anthropometry for either group following training. These results suggest that when training volume and load are matched, despite a smaller increase in strength, 5 weeks of training with short rest periods results in greater improvements in repeated-sprint ability than the same training with long rest periods.     

Comparison of two Actigraph models for assessing free-living physical activity in Indian adolescents

This aim of this study was to compare the new Actigraph (GT1M) with the widely used Model 7164. Seven days of free-living physical activity were measured simultaneously using both the Model 7164 and GT1M in 30 Indian adolescents (mean age 15.8 years, s = 0.6). The GT1M was on average 9% lower per epoch than model 7164, thus a correction factor of 0.91 is suggested for comparison between the two monitors. The differences between monitors increased in magnitude with intensity of activity (P < 0.001) but remained randomly distributed (r = 0.01, P = 0.96). No significant difference was observed between monitors for time spent in moderate (P = 0.31) and vigorous (P = 0.34) physical activity when using the same epoch length. The Model 7164 classified less time as sedentary (P < 0.001) and more time as light-intensity activity (P < 0.001) than the GT1M. In conclusion, data from the GT1M can be compared with historical data using average counts per minute with a correction factor, and the two models might be comparable for assessing time spent in moderate to vigorous physical activity in children when using the same epoch length.     

Decision-making skills and deliberate practice in elite association football referees

We examined sport expertise as a function of role. In study 1, referees were better than players in a video-based decision-making task. This provides evidence that there are role-specific skills within one domain or sport. In study 2, we examined the training activities that could be influential in the development of skills in sports officials. Elite association football (soccer) referees retrospectively reported time spent in and perceptions of training activities for three periods: their first year of formal refereeing, 1998 (before formal training programmes were available), and the current year (2003). This allowed us to examine an area of skill with a limited culture of practice, where performance simulations with direct feedback are usually not feasible. The results showed that referees specialize early and, as they develop, they engage in greater volumes and types of training. Competitive match refereeing is considered a relevant activity for skill acquisition that does not fit Ericsson and colleagues' (1993) original definition of deliberate practice. Our findings indicate that actual performance is a significant activity for skill acquisition and refinement.     

Coaches' encouragement of athletes' imagery use

To investigate whether coaches encourage their athletes to use imagery, two studies were undertaken. In the first, 317 athletes completed the Coaches' Encouragement of Athletes' Imagery Use Questionnaire. In the second, 215 coaches completed a slightly modified version of this questionnaire. It was found that coaches and athletes generally agreed on the relative frequency with which coaches encourage athletes to use imagery across the 4 Ws (i.e., where, when, why, and what). Coaches promoted imagery use more in conjunction with competition than training and injury rehabilitation, and higher-level coaches encouraged imagery use far more than their recreational counterparts. In addition, the level of athlete being coached had a major impact on how much or little coaches encouraged their athletes to use imagery. Coaches encouraged higher level athletes (i.e., international, national, varsity) to use imagery more than club and recreational athletes.     

The effect of periodized resistance training on accelerative sprint performance

The purpose of this study was to assess the effect of periodized resistance training on accelerative sprint performance. Sixteen physically active men participated in a randomized controlled study. An experimental group (n = 10) completed an 8-week periodized resistance training intervention, while a control group (n = 6) did not train. Pre- and post-training measures of 20-m straight-line sprint time, including a 10-m split, maximum strength, and explosive strength, were recorded. Flight time, stance time, stride length, and stride frequency were quantified from digitized video recordings of the first three strides of the 20-m sprint. Resistance training resulted in significant increases in maximum strength (parallel back squat: 19%) and explosive strength (6-10%). However, both groups increased 0-10 m sprint times (experimental group = 6%; control group = 3%) while 10-20m times were reduced (experimental group = 7%; control group = 4%), highlighting the mechanical differences between the distinct sprint phases. The change during the 0-10m interval was accompanied by a reduction in stride frequency during the first three strides. Strength coaches should be aware that the potential benefits of increased muscular strength during short sprints are likely to be affected by mechanical specificity and that improvements in sprinting performance may not occur immediately after a period of resistance training.     

新媒体联盟地平线报告:2016高等教育版

未来五年高等教育机构将会面临什么形势?有哪些趋势和技术将会驱动教育的变革?有哪些挑战是我们认为可以解决或难以克服的?《新媒体联盟地平线报告:2016高等教育版》揭示了未来五年全球范围内影响高等教育变化的关键趋势、重要挑战和重要的技术发展.图1是报告的内容框架.