Training in interactive sports     

Karen Zentgraf  Holger Heppe  Marie-Therese Fleddermann 《Sportwissenschaft》2017,47(1):2-14

The general purpose of this systematic review was to study the effectiveness of off-court perceptual–cognitive training interventions in nonnovice, interactive sport athletes. We looked at task-specific practice effects and, more importantly, the transfer of effects. Databases used for the literature search were PubMed, Web of Science, and PsycINFO. In all, 16 studies were found to be eligible for this review. These studies were independently evaluated by four reviewers for methodological quality and their evidence for specific practice effects and transfer effects. The effectiveness was analyzed with respect to the level of transfer, i.?e., from training-task-specific effects to near-transfer (e.?g., a similar perceptual task), further-transfer (e.?g., a sensorimotor sports skill), and far-transfer (e.?g., competition performance) intervention effects. Analyses of the 16 included studies suggest that around 60% of the training-specific measures tested after off-court practicing perceptual–cognitive training in sports athletes signal performance enhancement. However, transfer, be it near, further or far, is mostly not studied empirically; if studied, there is currently only limited and weak evidence for intermediate and far transfer. To reason that perceptual–cognitive off-court training interventions are ineffective might be premature at this point of time as methodological quality can still be improved and only a very limited number of studies actually included transfer variables. In those few studies integrating transfer variables, results are mixed and inconsistent. Future work should focus on critical factors to assure transfer of perceptual–cognitive training interventions.  相似文献   

Heat transfer variations of bicycle helmets   总被引：1，自引：0，他引：1  

Brühwiler PA  Buyan M  Huber R  Bogerd CP  Sznitman J  Graf SF  Rösgen T 《Journal of sports sciences》2006,24(9):999-1011

Bicycle helmets exhibit complex structures so as to combine impact protection with ventilation. A quantitative experimental measure of the state of the art and variations therein is a first step towards establishing principles of bicycle helmet ventilation. A thermal headform mounted in a climate-regulated wind tunnel was used to study the ventilation efficiency of 24 bicycle helmets at two wind speeds. Flow visualization in a water tunnel with a second headform demonstrated the flow patterns involved. The influence of design details such as channel length and vent placement was studied, as well as the impact of hair. Differences in heat transfer among the helmets of up to 30% (scalp) and 10% (face) were observed, with the nude headform showing the highest values. On occasion, a negative role of some vents for forced convection was demonstrated. A weak correlation was found between the projected vent cross-section and heat transfer variations when changing the head tilt angle. A simple analytical model is introduced that facilitates the understanding of forced convection phenomena. A weak correlation between exposed scalp area and heat transfer was deduced. Adding a wig reduces the heat transfer by approximately a factor of 8 in the scalp region and up to one-third for the rest of the head for a selection of the best ventilated helmets. The results suggest that there is significant optimization potential within the basic helmet structure represented in modern bicycle helmets.  相似文献   

The impact of instruction and student characteristics on the development of students’ ability to read texts with instructional pictures     

Oerke  Britta  McElvany  Nele  Ohle-Peters  Annika  Horz  Holger  Ullrich  Mark 《European Journal of Psychology of Education - EJPE》2019,34(2):375-395

European Journal of Psychology of Education - Reading texts with instructional pictures (text-picture integration) is a key component of students’ learning processes in most school subjects,...  相似文献   

Interplay of secondary pre-service teacher content knowledge (CK), pedagogical content knowledge (PCK) and attitudes regarding scientific inquiry teaching within teacher training     

Robbert Smit  Holger Weitzel  Robert Blank  Florian Rietz  Josiane Tardent  Nicolas Robin 《Research in Science & Technological Education》2017,35(4):477-499

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Dreamings beyond ‘opportunity’: the collaborative economics of an aboriginal heritage trail     

Carsten Holger Wergin 《Journal of Cultural Economy》2016,9(5):488-506

This article presents the Lurujarri Heritage Trail, an Indigenous tourism experience in Northwest Australia as exemplary for a world different from the teleological-minded futurism of neoliberal market economics. Drawing on long-term ethnographic fieldwork undertaken between 2011 and 2015, it first outlines how in 1987 the Trail was established at the very margins of the Australian economy. Through its emphasis on the here and now that is grounded in a collaboration of people and land and acknowledges diverse worldviews and ontological differences, the Trail today offers its participants a means to experience Indigenous culture as different from Western politics and development policies. As a result, its allegedly marginal Dreaming (Bugarrigarra) leads beyond the pursuit of economic opportunity and in doing so enabled the defeat of large-scale industrialisation in the region.  相似文献   

建立在几何交互式教学基础上的因特网     

Klaus-D.Graf  孙连举  马丽 《数学教育学报》2002,11(2):81-83

随着计算机的广泛普及和互联网的迅猛发展，数学教育也越来越朝着信息化、媒体化的方向发展，进而带来数学教育的深刻变化。在几何教学过程中，教育者应充分利用计算机作为图形计算器来处理几何问题。这将给学生巨大的探索和实验的空间，应用先进的多媒体技术进行教学活动，对改变传统的数学课堂教学模式，实现研究性学习和开放式教学有着积极的促进作用。  相似文献   

Output-sensitive autocompletion search     

Holger Bast  Christian W. Mortensen  Ingmar Weber 《Information Retrieval》2008,11(4):269-286

We consider the following autocompletion search scenario: imagine a user of a search engine typing a query; then with every keystroke display those completions of the last query word that would lead to the best hits, and also display the best such hits. The following problem is at the core of this feature: for a fixed document collection, given a set D of documents, and an alphabetical range W of words, compute the set of all word-in-document pairs (w, d) from the collection such that w ∈ W and d ∈ D. We present a new data structure with the help of which such autocompletion queries can be processed, on the average, in time linear in the input plus output size, independent of the size of the underlying document collection. At the same time, our data structure uses no more space than an inverted index. Actual query processing times on a large test collection correlate almost perfectly with our theoretical bound.

Ingmar WeberEmail:

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Radicalism in composition pedagogy     

Axel Polleres  Holger Lausen  Rubén Lara 《Academic Questions》1992,5(2):76-80

For the Record

Radicalism in composition pedagogy  相似文献   

Dynamics of coordination within elite rowing crews: evidence from force pattern analysis.     

Holger Hill 《Journal of sports sciences》2002,20(2):101-117

For a rowing crew to be successful, the movements of the rowers need to be well coordinated. Because rowers show individual force patterns, they have to adapt their movements when rowing as a crew. In this exploratory study, these hypothesized changes in movement pattern were examined. The force graphs of six elite coxless fours crews were recorded over 11 training runs using strain gauges attached to the oars. A detailed force analysis showed that form differences, but not area differences, between force patterns decreased when force output increased as a result of two different processes. First, increasing force output reduced form differences instantaneously by reducing the individual variation in force patterns. Secondly, the kinaesthetic perception of form differences is easier than that of area differences. This better perception facilitates the adaptation of movement patterns, especially when force output is high.  相似文献   

Politics and the 'Environment’ in Twentieth-Century Germany     

Holger Nehring 《Minerva》2006,44(3):338-354

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