Although many studies have focused on the importance of school composition for student achievement, there is still no consensus on whether school composition matters to student achievement, and, if so, why. Therefore, the present study investigates the association between school composition and mathematics achievement at the end of second grade in Flanders. International research points to the initial ability level, SES, ethnicity and sex composition of the school as potential variables in explaining differences in student achievement. Moreover, some researchers suggest that schools ‘react’ to their student body and for that reason we investigated the possible association between school composition and school processes. Data from the SiBO Project have been analyzed using multilevel regression and multilevel mediation analysis. The results showed no direct school composition effects with respect to prior achievement, SES, ethnicity and sex on math achievement. We found two small differential effects, indicating that mean school prior achievement seems to positively affect initially high achievers, and the proportion of minority students in school seems to negatively affect students speaking a non‐European language except for Turkish, Arabic or Berber at home. Furthermore, two small indirect effects were found which suggest that schools with a high mean prior achievement or a high mean SES keep in regular contact with their students' parents and this, in turn, appears to enhance students' math achievement. Overall, our results seem to indicate that school composition in the early years of primary education hardly matters. 相似文献
In this paper, we analyze and compare two didactical designs for introducing primary school pupils to proportional reasoning
in the context of plane polygons. One of them is well-documented in the literature; the other one is based on our own data
and is accordingly presented and discussed in more detail in this paper. The two designs come from different cultural and
intellectual environments: lesson study in Japan (implicitly based on the “open approach method”) and “didactical engineering”
in France (based on the theory of didactical situations). The general aim of our paper is to compare these two environments
and their approaches to didactical design, basing our discussion on the concrete designs mentioned above. Clear differences
among them are presented, while we also identify links which hold potential for integrating research and practice. 相似文献
ABSTRACTThe research focuses on the complexities associated with contemporary rural primary school leadership. The paper draws on in-depth ethnographic research undertaken in two contrasting English rural primary schools and their surrounding community over a period of three years and in particular the experiences and perspectives of the two head teachers from these schools. The paper is conceptually informed by the work of Bourdieu [1984. Distinction: A Social Critique of the Judgement of Taste. London: Routledge and Kegan Paul] and his work around field, habitus and capital as a means of understanding practice. The paper contends that as the neo-liberal economic field increasingly contaminates the field of schooling so a contextual understanding of the complex and shifting social space which a head teacher occupies, including their habitus and the capital they deploy, is of central importance to understanding practice. 相似文献
Given that physical activity (PA) tends to decrease with age during adolescence, addressing factors that affect change is important. This study examined the similarity and interdependence of PA as influenced by psychosocial factors among adolescent best friend dyads. A total of 660 adolescents, representing 330 best friend dyads, completed questionnaires with regard to PA, sitting time, perceived exercise benefits and barriers, physical self-perception and social support for PA. Dyads were also identified as reciprocal and non-reciprocal best friends; reciprocal means that both considered each other best friends and non-reciprocal were those in which only one considered the other a best friend. Data were analysed using a hierarchical linear model framework. Results indicated significant similarities between reciprocal best friend dyads for PA and sitting time, and for sitting time in non-reciprocal best friends (P values <.01). Psychosocial variables were associated with PA in reciprocal best friend dyads and with sitting time in reciprocal and non-reciprocal best friend dyads. Best friend gender, regular sports practice of the person, perceived exercise barriers of the best friend and best friend social support were the best predictors for PA. 相似文献
‘A tribute to Dr J. Rogge’ aims to systematically review muscle activity and muscle fatigue during sustained submaximal quasi-isometric knee extension exercise (hiking) related to Olympic dinghy sailing as a tribute to Dr Rogge’s merits in the world of sports. Dr Jacques Rogge is not only the former President of the International Olympic Committee, he was also an orthopaedic surgeon and a keen sailor, competing at three Olympic Games. In 1972, in fulfilment of the requirements for the degree of Master in Sports Medicine, he was the first who studied a sailors’ muscle activity by means of invasive needle electromyography (EMG) during a specific sailing technique (hiking) on a self-constructed sailing ergometer. Hiking is a bilateral and multi-joint submaximal quasi-isometric movement which dinghy sailors use to optimize boat speed and to prevent the boat from capsizing. Large stresses are generated in the anterior muscles that cross the knee and hip joint, mainly employing the quadriceps at an intensity of 30–40% maximal voluntary contraction (MVC), sometimes exceeding 100% MVC. Better sailing level is partially determined by a lower rate of neuromuscular fatigue during hiking and for ≈60% predicted by a higher maximal isometric quadriceps strength. Although useful in exercise testing, prediction of hiking endurance capacity based on the changes in surface EMG in thigh and trunk muscles during a hiking maintenance task is not reliable. This could probably be explained by the varying exercise intensity and joint angles, and the great number of muscles and joints involved in hiking.Highlights
Dr Jacques Rogge, former president of the International Olympic Committee and Olympic Finn sailor, was the first to study muscle activity during sailing using invasive needle EMG to obtain his Master degree in Sports Medicine at the Ghent University.
Hiking is a critical bilateral and multi-joint movement during dinghy racing, accounting for >60% of the total upwind leg time. Hiking generates large stresses in the anterior muscles that cross the knee and hip joint.
Hiking is considered as a quasi-isometric bilateral knee extension exercise. Muscle activity measurements during sailing, recorded by means of EMG, show a mean contraction intensity of 30-40% maximal voluntary contraction with peaks exceeding 100%.
Hiking performance is strongly related to the development of neuromuscular fatigue in the quadriceps muscle. Since maximal strength is an important determinant of neuromuscular fatigue during hiking, combined strength and endurance training should be incorporated in the training program of dinghy sailors.
AbstractPost-exercise recovery is a multi-facetted process that will vary depending on the nature of the exercise, the time between exercise sessions and the goals of the exerciser. From a nutritional perspective, the main considerations are: (1) optimisation of muscle protein turnover; (2) glycogen resynthesis; (3) rehydration; (4) management of muscle soreness; (5) appropriate management of energy balance. Milk is approximately isotonic (osmolality of 280–290?mosmol/kg), and the mixture of high quality protein, carbohydrate, water and micronutrients (particularly sodium) make it uniquely suitable as a post-exercise recovery drink in many exercise scenarios. Research has shown that ingestion of milk post-exercise has the potential to beneficially impact both acute recovery and chronic training adaptation. Milk augments post-exercise muscle protein synthesis and rehydration, can contribute to post-exercise glycogen resynthesis, and attenuates post-exercise muscle soreness/function losses. For these aspects of recovery, milk is at least comparable and often out performs most commercially available recovery drinks, but is available at a fraction of the cost, making it a cheap and easy option to facilitate post-exercise recovery. Milk ingestion post-exercise has also been shown to attenuate subsequent energy intake and may lead to more favourable body composition changes with exercise training. This means that those exercising for weight management purposes might be able to beneficially influence post-exercise recovery, whilst maintaining the energy deficit created by exercise. 相似文献