The "how" and "why" of the ancient Greek long jump with weights: a five-fold symmetric jump in a row?     

Lenoir M  De Clercq D  Laporte W 《Journal of sports sciences》2005,23(10):1033-1043

A plausible explanation for the ancient long jump records from Greek antiquity is sought on the basis of pictorial and written sources, and corroborated with practical tests. Ancient sources report that athletes jumped more than 15 m with weights in their hands, which enabled them to jump further than without these weights. It is proposed that the ancient Greek long jump was a continuous succession of five standing broad jumps, in which the landing phase of one jump was also the countermovement for the next jump. Four trained athletes jumped further with (14.64 +/- 0.76 m, range 13.64-15.63 m) than without weights (13.88 +/- 0.70 m, range 12.60-14.75 m; P = 0.001). These results show that this technique is executable, fits with ancient written and pictorial sources, and allows trained modern athletes to jump distances well over 15 m. The extra distance jumped when using weights may be due to changes in the position of the jumper's centre of mass at take-off and at landing, and an increase in take-off velocity stemming from several biomechanical mechanisms.  相似文献   

Can LEDs help with art conservation? – Impact of different light spectra on paint pigment degradation     

Manuela Lunz  Elise Talgorn  Jannie Baken  Wiebe Wagemans  Dirk Veldman 《文物保护研究》2017,62(5):294-303

The impact of the spectral composition of light on the discoloration of paint pigments has been investigated for the case of lead chromate sulfate, an unstable yellow pigment used by Vincent van Gogh and other painters. With LEDification, museum lighting is moving from using halogen to LED lamps. LED light sources have a significantly different spectral composition than halogen lamps. To understand the impact of these differences on pigment stability, the wavelength dependence of pigment discoloration was determined. Contrary to the expectation that lower wavelength photons induce more damage than higher wavelength ones, UV (394?nm), blue, and cyan light all lead to similar levels of discoloration of a pigment for the same level of radiant power. By understanding this wavelength dependence, it becomes possible to create white light LED lamps with a spectral composition tuned to minimize the degradation effect. An existing LED solution with a modified emission indeed resulted in 30% less color change in the experiment than halogen. Furthermore, a method is proposed to optimize the LED spectra by tuning to the properties of each specific artifact. Simulations show that this can reduce the damage of the light source by 45% in specific cases.  相似文献   

Effects of a multifactorial injury prevention intervention in physical education teachers: A randomized controlled trial     

Sien Vercruysse  Leen Haerens  Evert Verhagen  Lennert Goossens  Dirk De Clercq 《European Journal of Sport Science》2016,16(7):868-876

Physical education (PE) teachers are at a high risk of musculoskeletal sports or work-related injuries because of the physical activity as inherent part of their profession. Such injuries have a negative impact on work and leisure time activities, and effective injury prevention interventions are needed. The present study aimed at testing the effectiveness of an injury prevention intervention that was developed and optimized according to PE teachers' wishes and values. Fifty-five PE teachers were randomly assigned to intervention or control group. Intervention group teachers engaged in two days of training during which they familiarized with eight injury prevention strategies (seven intrinsic and one extrinsic). A special feature of the intervention was that the way of delivery was based on the self-determination theory in order to stimulate participants' motivation to adhere to the proposed strategies. Prospective registrations during one school year were conducted concerning injuries and preventive behaviours. Results showed that the intervention group teachers had a lower number of injuries per 1000?h time of exposure (TOE) than the controls (INT: 0.49, CON: 1.14 injuries/1000?h TOE, OR: 2.32, 95% CI: 1.06–5.07), and applied a broader variety of strategies including dynamic and static stretching, core stability, balance and strength training, when compared to the controls who mainly engaged in warming-up. In conclusion, with the same amount of time, an injury reduction was found in PE teachers through a more balanced use of provided preventive strategies.  相似文献   

Development and Application of a Category System to Describe Pre-Service Science Teachers’ Activities in the Process of Scientific Modelling     

Krell  Moritz  Walzer  Christine  Hergert  Susann  Krüger  Dirk 《Research in Science Education》2019,49(5):1319-1345

Research in Science Education - As part of their professional competencies, science teachers need an elaborate meta-modelling knowledge as well as modelling skills in order to guide and monitor...  相似文献   

Overcoming cross-cultural group work tensions: mixed student perspectives on the role of social relationships     

Jenna Mittelmeier  Bart Rienties  Dirk Tempelaar  Denise Whitelock 《Higher Education》2018,75(1):149-166

As universities worldwide rapidly internationalise, higher education classrooms have become unique spaces for collaboration between students from different countries. One common way to encourage collaboration between diverse peers is through group work. However, previous research has highlighted that cross-cultural group work can be challenging and has hinted at potential social tensions. To understand this notion better, we have used robust quantitative tools in this study to select 20 participants from a larger classroom of 860 students to take part in an in-depth qualitative interview about cross-cultural group work experiences. Participant views on social tensions in cross-cultural group work were elicited using a unique mediating artefact method to encourage reflection and in-depth discussion. In our analysis of emergent interview themes, we compared student perspectives on the role of social relationships in group work by their academic performance level. Our findings indicated that all students interviewed desired the opportunity to form social relationships with their group work members, but their motivations for doing so varied widely by academic performance level.  相似文献   

Values education and student satisfaction: German business students' perceptions of universities' value influences     

Dirk C. Moosmayer  Florian U. Siems 《Journal of Marketing for HIGHER EDUCATION》2013,23(2):257-272

As a result of the past decade's financial crises, the focus on students' values as an output of higher management education has increased. Simultaneously, marketing theory has become prevalent in the management of higher education institutions, such that student satisfaction represents a key output variable for their service provision. This study integrates both perspectives to investigate how values-oriented education relates to student satisfaction. A sample of 191 respondents from a German university reveals that business students expect more value influence than they believe their institution actually delivers. Furthermore, students' perceptions of the value influence delivered by their university increase their satisfaction with the institution. Finally, the value influence students expect is more closely associated with universalism values (connected to sustainability and CSR) than with power values. These results imply that universities can increase student satisfaction if they coordinate opportunities to discuss and shape values, particularly with regard to universalism ideals.  相似文献   

Fifteen years of action research for political and educational emancipation at a South African University   总被引：1，自引：1，他引：0  

Maureen Robinson  Dirk Meerkotter 《Educational Action Research》2013,21(3):447-466

This article traces the origins and development of an action research Master's in Education programme, which was introduced in the Faculty of Education at the University of the Western Cape, South Africa in the mid-1980s. The programme began during a time of political and social repression, when the apartheid government was very much in control, and was explicitly located within an emancipatory approach to education. The article discusses the vision of emancipatory education that underpinned the programme, linking this to the political situation of domination and resistance in the educational sector. The origins of People's Education are described, as well as various initiatives in action research which were closely linked to the People's Education movement of the time. The article concludes by discussing some of the new challenges for action research and emancipatory education in the post-apartheid era.  相似文献   

Relational, structural, and semantic analysis of graphical representations and concept maps     

Dirk Ifenthaler 《Educational technology research and development : ETR & D》2010,58(1):81-97

The demand for good instructional environments presupposes valid and reliable analytical instruments for educational research. This paper introduces the SMD Technology (Surface, Matching, Deep Structure), which measures relational, structural, and semantic levels of graphical representations and concept maps. The reliability and validity of the computer-based and automated SMD Technology was tested in three experimental studies with 106 participants. The findings indicate a high reliability and validity. The discussion focuses on the development and realization of the three levels of the SMD Technology and applications for research, learning and instruction.  相似文献   

Quality issues in the internationalisation of higher education   总被引：5，自引：0，他引：5  

Dirk Van Damme 《Higher Education》2001,41(4):415-441

Although the quality issue has become a central preoccupation inother domains of higher education, current internationalisation policiesand practices in higher education have developed without much concernfor quality assurance. The central thesis of this paper is that we havecome to a point in the development of higher education whereinternationalisation policies and practices face the limits of theirdevelopment unless the quality challenge is addressed in all itsconsequences. The paper first provides an overview of contemporary formsof and recent developments in internationalisation in higher education.From more or less `traditional' forms such as student and teaching staffmobility, internationalisation policies and practices nowadays move intoactivities such as exporting higher education via branch campuses andinstitutional co-operation, developing transnational university networksand virtual delivery of higher education, and the harmonisation ofhigher education systems. In these recent developments several issuesand challenges arise, which in one kind or another have direct links tothe quality challenge. The quality of internationalisation policies andpractices itself is an important problem, but of more importance are theissues of the recognition of foreign diplomas and degrees and therecognition of credits and credit-transfer. This paper takes a criticalstance towards for example the ECTS, which tries to solve these issueswithout much concern for quality. The way out lies in an integration ofinternationalisation policies and general quality assurance practices atinstitutional and policy levels.  相似文献   

1. Karl H. Hörning: Experten des Alltags. Die Wiederentdeckung des praktischen Wissens     

Claus J. Tully  Dirk Baier 《Zeitschrift für Erziehungswissenschaft》2003,6(2):300-301

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