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991.
The present study aims to identify first year Turkish Science undergraduates’ understandings and misconceptions of the concept of light and its propagation. For this purpose, an instrument composed of four open-ended questions was developed by the researchers. The diagnostic test was piloted with twenty students and modifications were made prior to the final administration of the test. The content validity of the test questions was assessed by two physics researchers and one lecturer. These questions were administered to a hundred first year undergraduates (aged 16–18) enrolled in the Science Teacher Training Department in Ataturk University in Turkey. In addition, the semi-structured interviews of 30–40 min were conducted with the four students whose responses involved common misunderstanding. All interview records were transcribed and analysed. The findings showed that undergraduates’ understanding of light is poor and also they have important and prevalent misconceptions. Identified misconceptions, some of which have been reported in the literature, are discussed qualitatively. The misunderstandings identified were compared with those in the literature. The results have some implications for teaching light, suggesting that a substantial revision of teaching strategies is needed.
Mehmet YalcinEmail:
  相似文献   
992.
In the past few decades, much research has documented the importance of users as sources of innovations. Over the last 10 years, Research Policy alone has published 56 research articles investigating this phenomenon. We ask to what degree the findings of users as innovators have been absorbed by decision-makers responsible for new product development (managers) and by those who shape the contextual conditions for innovation (policy makers and public administration). A realistic perception of the sources of innovation is important as it constitutes the basis for a rational allocation of resources and thus indirectly impacts the innovation performance of companies and societies at large.In a large-scale survey of n?=?1500 decision-makers, we found support for a substantial underestimation of users as a source of innovation: While the true proportion of user innovation among the most valuable 1678 innovations in nine industries is 54.4% (as established in existing research articles), decision-makers estimate it to be 21.7%. A content analysis of transfer media (450 academic textbooks, popular innovation books, and business articles) underscores this theory-practice gap: Of 3469 text paragraphs dealing with the sources of innovation, only 2.7% mention users as innovators. We develop six propositions on the reasons for and consequences of this underestimation that may serve as a starting point for future research and practical consequences.  相似文献   
993.
There is a growing interest in exploring irisin response to acute exercise; however, the associations of acute exercise-induced irisin release with training status and exercise mode are not fully understood. This study was primarily designed to evaluate these associations. Sixteen healthy adults (8 trained versus 8 untrained) underwent a bout of cycling at 80% of maximal oxygen uptake (VO2max) for 50?min, with blood drawn pre-, 10-, and 180-min post-exercise. Another 17 healthy adults performed 2 bouts of graded exercise (cycling and running) until exhaustion on separate days using a randomized cross-over design, with blood taken pre-, 0-, 10-, and 60-min post-exercise. Circulating irisin, creatine kinase (CK), aspartate aminotransferase (AST), and myoglobin (Mb) were measured, and their respective areas under the curves (AUCs) were calculated. Irisin increased 10-min after 50?min of cycling at 80% of VO2max, while its changes from baseline to post-exercise and the amount of exercise-induced irisin release (presented as AUC) were comparable between trained and untrained adults (all P?>?.05). Irisin remained elevated 10-min post-exhausting running but decreased towards baseline 10-min post-exhausting cycling. Exhausting running induced an increase in irisin release for the whole course of exercise and recovery periods, but cycling did not. Acute exercise-induced irisin changes seemed not related to changes of CK, aspartate AST, and Mb in general. In conclusion, acute exercise-induced irisin release is not associated with training status but might be affected by training mode. Future studies are required to investigate which exercise mode might be most efficient in altering irisin.  相似文献   
994.
Despite accumulating evidence that regular exercise improves executive functioning, the underlying neurophysiological mechanisms have rarely been investigated. The present study aimed to compare cognitive performance as well as task-specific concentration changes in oxygenated haemoglobin in the prefrontal cortex between children with higher and lower moderate-to-vigorous physical activity (MVPA). Physical activity was measured over 7 consecutive days using actigraphy. Afterwards, participants (N = 50) completed verbal fluency tests (VFTs) and mental arithmetic (MA) for the assessment of cognitive flexibility and working memory capacity. During the tasks, changes of oxygenated haemoglobin were measured with functional near-infrared spectroscopy. Using average MVPA of 11-year-old children as cut-point, the sample was divided into children with lower and higher MVPA. Analyses of variance revealed no significant differences in correct and false responses on the cognitive tests between groups. With regard to oxygenated haemoglobin, no group differences were found for concentration changes in response to the cognitive tasks. In conclusion, VFTs and MA increased children’s activation in prefrontal regions associated with cognitive flexibility and working memory, respectively. However, these executive functions and cortical activation were not different between children with lower and higher MVPA.  相似文献   
995.
The jump throw is one of the most applied techniques in handball. Therefore, analyzing its underlying performance factors is important since they may provide a basis to adjust training interventions. Currently, the coach decides what needs to be improved in order to enhance the overall performance of an athlete. The aim of this study is to break down the performance factors in jump throws and to assign athletes to subgroups. This classification should allow athletes to benefit from the resulting group-specific training contents and may support a coach in deciding about the next steps in his training program. A total of 113 male handball players (age 15 ± 0.38 years, height 184.07 ± 7.1?cm, weight 74.83 ± 9.31?kg) participated in this study. From each athlete the standing reach height (SRH), the jumping reach height achieved with a countermovement jump (JRH), the maximal ball height achieved with a handball-specific single-legged jump and straight arm (BHJ), and the ball release height achieved in a jump throw (BHT) were measured. Performance factors were derived as differences between these measurements (JRH ? SRH = UJA for unspecific jump ability, BHJ ? JRH = SJT for specific jump technique, BHT ? BHJ = STT for specific throwing technique). A hierarchical cluster analysis was used to find groups of athletes based on the derived and scaled difference measures (UJA, SJT, STT). The dendrogram shows a clear distinction of four groups of athletes. Average values within each cluster reveal (A) one group with high UJA values, (B) one with low UJA values, (C) one with high SJT but low STT, and (D) one with low SJT but high STT. These results may be interpreted with respect to consequences for training because group (B) seems to benefit most from a general strength training while the properties of group (A), (C), and (D) recommend a focus on technical aspects of performance.  相似文献   
996.
In basketball, the defender’s reaction to a pass is slower and more error prone if the attacking player gazes into the opposite direction. This so-called head-fake effect might be modulated by context information, that is, the frequency and the sequence of head fakes occurring. Accordingly, the present study investigates the head-fake effect for different frequency proportions (20% vs. 50% vs. 80%). The results show that the head-fake effect decreases when the head fake occurs more often. Furthermore, a potential influence of previous fake experience (i.e., congruency-sequence effect) on the size of the head-fake effect was investigated. Importantly, previous fake experience did not cause the frequency-based modulation of the general size of the head-fake effect. These findings bare important implications for sports practice, especially when it comes to instructing players about the tactical use of deceptive actions.  相似文献   
997.
Abstract

Germany is both the country of origin of Protestantism and of Turnerism, which has led to a specific concept of national gymnastics. In 2017, the 500th anniversary of Martin Luther´s act of nailing his theses to the door of the Church of Wittenberg (on 31 October 1517) was celebrated. About 300 hundred years later, Ludwig Jahn, son of a Protestant minister, started to run a gymnastics ground at a park in Berlin, where young boys and students were educated in ‘body and mind’ according to Jahn’s slogan (which later became the brand of the German Turner movement) frisch, fromm, fröhlich, frei (‘fresh, pious, cheerful, free’). The notion of piety has been widely discussed by contemporary gymnasts, because even then, some regarded piety as old-fashioned and in fact incompatible with a free and enlightened world. The purpose of this paper is to consider the Christian impact on German gymnastics and sport since the beginning of a civil movement of body culture in clubs and societies in the nineteenth century. The paper is based on a wide range of academic research and other selected sources.  相似文献   
998.
Our lives are increasingly intertwined with the digital realm, and with new technology, new ethical problems emerge. The academic field that addresses these problems—which we tentatively call ‘digital ethics’—can be an important intellectual resource for policy making and regulation. This is why it is important to understand how the new ethical challenges of a digital society are being met by academic research. We have undertaken a scientometric analysis to arrive at a better understanding of the nature, scope and dynamics of the field of digital ethics. Our approach in this paper shows how the field of digital ethics is distributed over various academic disciplines. By first having experts select a collection of keywords central to digital ethics, we have generated a dataset of articles discussing these issues. This approach allows us to generate a scientometric visualisation of the field of digital ethics, without being constrained by any preconceived definitions of academic disciplines. We have first of all found that the number of publications pertaining to digital ethics is exponentially increasing. We furthermore established that whereas one may expect digital ethics to be a species of ethics, we in fact found that the various questions pertaining to digital ethics are predominantly being discussed in computer science, law and biomedical science. It is in these fields, more than in the independent field of ethics, that ethical discourse is being developed around concrete and often technical issues. Moreover, it appears that some important ethical values are very prominent in one field (e.g., autonomy in medical science), while being almost absent in others. We conclude that to get a thorough understanding of, and grip on, all the hard ethical questions of a digital society, ethicists, policy makers and legal scholars will need to familiarize themselves with the concrete and practical work that is being done across a range of different scientific fields to deal with these questions.  相似文献   
999.
Quantum computing technologies have become a hot topic in academia and industry receiving much attention and financial support from all sides. Building a quantum computer that can be used practically is in itself an outstanding challenge that has become the ‘new race to the moon’. Next to researchers and vendors of future computing technologies, national authorities are showing strong interest in maturing this technology due to its known potential to break many of today’s encryption techniques, which would have significant and potentially disruptive impact on our society. It is, however, quite likely that quantum computing has beneficial impact on many computational disciplines. In this article we describe our vision of future developments in scientific computing that would be enabled by the advent of software-programmable quantum computers. We thereby assume that quantum computers will form part of a hybrid accelerated computing platform like GPUs and co-processor cards do today. In particular, we address the potential of quantum algorithms to bring major breakthroughs in applied mathematics and its applications. Finally, we give several examples that demonstrate the possible impact of quantum-accelerated scientific computing on society.  相似文献   
1000.
造成汉语报刊阅读教材出版周期长、时效性差的主要原因,是由于以往人工搜集整理语料的方法既费时又费力。编写者应该充分利用现代信息手段,即网络资源,不但能够大大地缩短教材的编写周期,而且便于将固定教材的使用与补充教材的选择有机地结合在一起,提高教材的编写质量。  相似文献   
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