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Knowledge Management Research & Practice - Admitting that knowledge workers and Knowledge Management Systems (KMSs) are valuable organizational assets whose interaction should be augmented,... 相似文献
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Constantinos?ChristouEmail author Nikos?Mousoulides Marios?Pittalis Demetra?Pitta-Pantazi 《International Journal of Science and Mathematics Education》2004,2(3):339-352
The recent development of powerful new technologies such as dynamic geometry software (DGS) with drag capability has made possible the continuous variation of geometric configurations and allows one to quickly and easily investigate whether particular conjectures are true or not. Because of the inductive nature of the DGS, the experimental-theoretical gap that exists in the acquisition and justification of geometrical knowledge becomes an important pedagogical concern. In this article we discuss the implications of the development of this new software for the teaching of proof and making proof meaningful to students. We describe how three prospective primary school teachers explored problems in geometry and how their constructions and conjectures led them see proofs in DGS.
Constantinos Christou: Author for correspondence. 相似文献
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Anna Efthimiadou Byron Asimakopoulos Nikos Nikolettos Alexandra Giatromanolaki Efthimios Sivridis Theodoros S. Lialiaris 《Journal of sports sciences》2013,31(8):849-854
Abstract Although angiogenetic therapy using recombinant growth factors holds much hope for the treatment of ischaemic diseases, there are still many unanswered questions, including the method of administration, the correct dose of these factors, and the duration of the therapeutic approach. Exercise has also been suggested to induce neovascularizaiton in muscles. We evaluated the angiogenetic effects of the intramuscular administration of basic-fibroblast growth factor (b-FGF) and acidic-fibroblast growth factor (a-FGF) in rat heart, compared with rats who exercised daily. In conclusion, both the intramuscular administration of b-FGF and exercise increased significantly angiogenesis in the heart in contrast to the intramuscular administration of a-FGF, which was ineffective. 相似文献
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Cecilie Th⊘gersen-Ntoumani Nikos Ntoumanis Nikitas Nikitaras 《Journal of sports sciences》2013,31(12):1341-1350
Abstract The main purpose of this study was to examine typologies of non-exercisers based on reasons for physical inactivity and conditions reported to be necessary to change exercise behaviour. These typologies were then compared on psychological variables of interest and exercise history. Questionnaires were distributed to Greek older adults aged 60 and above who were recruited from social clubs and city cafés. Only individuals engaging in no regular exercise were recruited (n = 188). The results of hierarchical and k-means cluster analyses revealed two clusters for males (“approachable” and “unconvinced”) and three for females (“unconcerned”, “approachable”, and “unconvinced”). The clusters differed significantly on psychological variables not used in the cluster solution. Exercise history distinguished between clusters only among males. The results reveal that physically inactive older adults are not a homogeneous group of individuals. Implementers of physical activity interventions should probably use a range of strategies that take into consideration that some sedentary older adults are more amenable to consider taking up exercise than others. 相似文献
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Abstract There has been very limited research on the use of self-worth protection strategies in the achievement context of school physical education (PE). Thus the aim of the present study was to examine some antecedents and consequences of defensive pessimism and self-handicapping. The sample comprised 534 British pupils (275 females, 259 males) recruited from two schools who responded to established questionnaires. Results of structural equation modelling analysis indicated that self-handicapping and defensive pessimism were positively predicted by fear of failure and negatively predicted by competence valuation. In addition, defensive pessimism was negatively predicted by physical self-concept. In turn, defensive pessimism negatively predicted enjoyment in PE and intentions to participate in future optional PE programmes. Self-handicapping did not predict enjoyment or intentions. Results from multi-sample structural equation modelling showed the specified model to be largely invariant across males and females. The findings indicate that although both strategies aim to protect one's self-worth, some of their antecedents and consequences in PE may differ. 相似文献
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Martin S. Hagger Nikos Chatzisarantis Stuart J.H. Biddle 《Journal of sports sciences》2013,31(9):711-725
The aim of the present study was to assess the influence of self-efficacy and past behaviour on young people's physical activity intentions using an augmented version of Ajzen's Theory of Planned Behaviour. We hypothesized that self-efficacy would exhibit discriminant validity with perceived behavioural control and explain unique variance in young people's intentions to participate in physical activity. We also expected that past physical activity behaviour would attenuate the influence of attitude, subjective norms, perceived behavioural control and self-efficacy on intention. The sample comprised 1152 young people aged 13.5 - 0.6 years (mean - s ) who completed inventories assessing their physical activity intentions, attitudes, subjective norms, perceived behavioural control, self-efficacy and past physical activity behaviour. A confirmatory factor analysis demonstrated that the constructs of the Theory of Planned Behaviour achieved discriminant validity. Furthermore, the measures of attitudes, subjective norms, perceived behavioural control and self-efficacy were significantly related to their respective belief-based measures, supporting the concurrent validity of the measures of the Theory of Planned Behaviour. A non-standard structural equation model demonstrated that attitude and self-efficacy were strong predictors of physical activity intention, but perceived behavioural control and subjective norms were not. Self-efficacy attenuated the influence of attitudes and perceived behavioural control on intention. Past behaviour predicted intention directly and indirectly through self-efficacy and attitude. The present findings demonstrate that young people with positive attitudes and high self-efficacy are more likely to form intentions to participate in physical activity. Furthermore, controlling for past physical activity behaviour revealed that the unique effects of self-efficacy and attitudes on young people's physical activity intentions were unaltered. 相似文献
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Nikos E. Kanderakis 《Science & Education》2009,18(9):1105-1113
According to the principle of virtual velocities, if on a simple machine in equilibrium we suppose a slight virtual movement,
then the ratio of weights or forces equals the inverse ratio of velocities or displacements. The product of the weight raised
or force applied multiplied by the height or displacement plays a central role there. British engineers used the same product
in the eighteenth century in order to measure steam engines’ effectiveness. The question is whether this measure was obviously
empirical or had its origin in theory of mechanics and particularly in the principle of virtual velocities. According to science
education research, this measure is not likely to have arisen intuitively and most probably could not have been formulated
without any acquaintance with theory of mechanics. 相似文献
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Nikos V. Margaritelis Anastasios A. Theodorou Antonios Kyparos Michalis G. Nikolaidis Vassilis Paschalis 《Journal of sports sciences》2019,37(14):1630-1637
Underfat individuals have been neglected as a malnourished population in terms of redox homeostasis. The aim of the present study was to evaluate the effect of body composition on redox homeostasis at rest and in response to exercise. Underfat, lean and overfat women, classified according to their BMI and body fat percentage, participated in the study and were subjected to an acute session of eccentric exercise. With regard to muscle function and damage, a significant group × time interaction was found for range of motion (P < .01), isometric peak torque at 90° (P < .01), delayed onset muscle soreness (P < .01) and creatine kinase (P < .05), with the lean group generally exhibiting faster recovery compared to the underfat and overfat groups. With regard to redox homeostasis, a significant group × time interaction was found for F2-isoprostanes, protein carbonyls and glutathione (P < .01 for all biomarkers), with the underfat and overfat groups exhibiting increased resting oxidative stress levels and lower exercise-induced reactive species production . In conclusively, our data underline the importance of normal body composition for redox homeostasis, since underfat and overfat women demonstrate a similar pattern of redox disturbances both at rest and in response to exercise. 相似文献
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Grounded in self-determination theory (Deci & Ryan, 1985), the purpose of the present study was to examine whether amotivation, self-determined and controlling types of motivation could predict a range of exercise-related behaviours, cognitions and physical self-evaluations. Exercisers (n = 375) from ten health clubs in the North of England completed questionnaires measuring exercise motivation, exercise stages of change, number of relapses from exercise, future intention to exercise, barriers self-efficacy, physical self-worth and social physique anxiety. Controlling for age and sex, multiple and logistic regression analyses supported our hypotheses by showing self-determined motivation (i.e. intrinsic motivation and identified regulation) to predict more adaptive behavioural, cognitive and physical self-evaluation patterns than external regulation and amotivation. Introjected regulation was related to both adaptive and maladaptive outcomes. Furthermore, a multivariate analysis of variance revealed that exercisers in the maintenance stage of change displayed significantly more self-determined motivation to exercise than those in the preparation and action stages. The results illustrate the importance of promoting self-determined motivation in exercisers to improve the quality of their experiences, as well as to foster their exercise behaviour. Future research should examine the mechanisms that promote self-determined motivation in exercise. 相似文献