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701.
Abstract

Relevant information on effectiveness of school-based drug prevention programmes is available. Despite this, there is still contradictory evidence that makes it necessary to continue to shed light on this issue. Based on a synthesis research method, the aim of this study was to determine the relevant variables that enhance the efficacy of these programmes and to determine the weight of their empirical evidence. Furthermore, several features of the evaluation designs whose variables had been proven effective were examined. A systematic review of periodical literature was conducted, which led us to extract 1,622 papers, of which 17 studies were analysed. An in-depth analysis of these publications led us to identify 29 key variables associated with the efficacy of the programme, which were ranked according to the weight of their empirical evidence. Moreover, the characteristics of the studies included in the review highlighted the need to improve the rigorousness and quality of the evaluation designs in this field.  相似文献   
702.
Se revisan y comparan aquí las características del método natural-global de Freinet y se sugiere su convergencia con las que se deducen de la psicología cognitiva para la enseñanza de la lectoescritura. A partir de ahí se propone una secuencia determinada y se dan una serie de recomendaciones para abordar con éxito la enseñanza de la lectura.  相似文献   
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704.
In the last two decades science studies and science education research have shifted from an interest in products (of science or of learning), to an interest in processes and practices. The focus of this paper is on students’ engagement in epistemic practices (Kelly in Teaching scientific inquiry: Recommendations for research and implementation. Sense Publishers, Rotterdam, pp 99–117, 2008), or on their practical epistemologies (Wickman in Sci Educ 88(3):325–344, 2004). In order to support these practices in genetics classrooms we need to take into account domain-specific features of the epistemology of genetics, in particular issues about determinism and underdetermination. I suggest that certain difficulties may be related to the specific nature of causality in genetics, and in particular to the correspondence between a given set of factors and a range of potential effects, rather than a single one. The paper seeks to bring together recent developments in the epistemology of biology and of genetics, on the one hand, with science education approaches about epistemic practices, on the other. The implications of these perspectives for current challenges in learning genetics are examined, focusing on students’ engagement in epistemic practices, as argumentation, understood as using evidence to evaluate knowledge claims. Engaging in argumentation in genetics classrooms is intertwined with practices such as using genetics models to build explanations, or framing genetics issues in their social context. These challenges are illustrated with studies making part of our research program in the USC.  相似文献   
705.
706.
To help organizations get closer to their value objectives, a number of approaches and fields of practice have been developed. Two fields common in today's business environment are human performance technology (HPT) and quality. The recent publication of the Global State of Quality Research: Discoveries 2013 by the American Society for Quality provides customer‐ and practitioner‐related data and offers an opportunity to link the purposes, philosophies, research, and practices of quality and HPT.  相似文献   
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709.
Free radical production increases during exercise and oxidative damage occurs in several tissues. We examined the effects of three different exercise tests on the pattern of change of erythrocyte enzyme antioxidant activities. The tests were a short maximal exercise test, a submaximal prolonged exercise test and a cycling stage during competition. The participants were amateur and professional cyclists with different training statuses and different basal erythrocyte antioxidant enzyme activities. The maximal test produced no changes in the erythrocyte antioxidant enzyme activities of amateur sportsmen. The submaximal test, performed at 80% of maximal oxygen uptake, decreased erythrocyte catalase (12%), glutathione peroxidase determined with H2O2 (14%) and glutathione reductase (16%); superoxide dismutase activity increased by about 25%. The cycling stage performed by professional cyclists increased erythrocyte catalase (29%) and glutathione reductase (10%) activities. The in vivo changes in glutathione reductase activity were confirmed by in vitro measurements: hydrogen peroxide decreased and the presence of catalase increased the activity of this enzyme. In conclusion, we suggest that the different erythrocyte antioxidant enzyme responses to diverse exercise tests can be explained by the effects of hydrogen peroxide and the superoxide anion on the antioxidant enzyme activities in erythrocytes.  相似文献   
710.
Abstract

Performance differences between males and females have been attributed to both biological and cultural factors, although the relative significance of each has not been ascertained. Differences in body fatness between males and females has been frequently mentioned as one biological factor responsible for variations in physical performance. In children, it has been shown that boys exhibit slightly higher performance levels than girls until adolescence, when the differences favoring the boys become greater. The purpose of this study was to investigate the relationship between selected physical performance tests and body fatness in preadolescent boys and girls. Measures of age, height, weight, skinfold thicknesses at two sites, and performance scores on the vertical jump, standing broad jump, modified pullup, 40-yard dash, and 400-yard run were obtained on 563 elementary school children. The results of a one-way ANOVA indicated that there was a significant difference between boys and girls on all of the physical performance tests. Although the boys were slightly taller and heavier and scored better than the girls on the performance tests, there was no significant difference between the sexes in the sum of two skinfolds. Separate regression equations for the sum of two skinfolds by performance on each test indicated that, with the exception of the modified pullup test, body fatness was only marginally related to performance. These findings indicated that, although inversely related to the ability to move the total body weight, body fatness was of minimal importance in explaining performance differences between young boys and girls.  相似文献   
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