Sequence-dependent rotation axis changes in tennis     

Clint Hansen  Caroline Martin  Nasser Rezzoug  Philippe Gorce  Benoit Bideau  Brice Isableu 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(3):411-423

The purpose of this study was to evaluate the role of rotation axes during a tennis serve. A motion capture system was used to evaluate the contribution of the potential axes of rotation (minimum inertia axis, shoulder-centre of mass axis and the shoulder-elbow axis) during the four discrete tennis serve phases (loading, cocking, acceleration and follow through). Ten ranked athletes (International Tennis Number 1–3) repeatedly performed a flat service aiming at a target on the other side of the net. The four serve phases are distinct and thus, each movement phase seems to be organised around specific rotation axes. The results showed that the limbs’ rotational axis does not necessarily coincide with the minimum inertia axis across the cocking phase of the tennis serve. Even though individual serving strategies were exposed, all participants showed an effect due to the cocking phase and changed the rotation axis during the task. Taken together, the results showed that despite inter-individual differences, nine out of 10 participants changed the rotation axis towards the minimum inertia and/or the mass axis in an endeavour to maximise external rotation of the shoulder to optimally prepare for the acceleration phase.  相似文献   

Archival representations of immigration and ethnicity in North American history: from the ethnicization of archives to the archivization of ethnicity     

Dominique Daniel 《Archival Science》2014,14(2):169-203

This article traces the representations of ethnicity and immigration in mainstream American and Canadian archives since the 1950s. It identifies three main periods of evolution of these ethnic archives: the era prior to the civil rights movement, the 1960–1980s and the 1990s and beyond. Relying on an understanding of archival collections as social constructions anchored in specific historical contexts, the article considers the various political, economic, social and technological factors that affected ethnic archives over time, especially as they relate to changing scholarly and popular conceptions of ethnicity in North America. It pays particular attention to the impact of historical scholarship in fields related to immigration and ethnicity and of postmodernist archival theories that challenge the traditional view of archives as evidence of the past. It suggests that the relationship between ethnic archives and their historical context is dialectical: not only are they affected by the context in which they are developed and managed, but they also have an impact on that context as they favor certain conceptions of ethnicity and types of ethnic groups at the expense of others. Both curators and users of archival materials should therefore pay closer attention to the history of the processes that went into the construction of these archives to avoid falling victims to the illusion of ethnic authenticity.  相似文献   

Trajectory-based real-time control of an electrical circuit against unknown faults     

Tushar Jain  Joseph J. Yamé  Dominique Sauter 《Journal of The Franklin Institute》2014

This paper presents a trajectory-based online control reconfiguration mechanism against unknown fault occurring in an electric circuit. First, we demonstrate the modeling of an electric circuit by taking the time-trajectory viewpoint, where no a priori input–output partition has been made. The uniqueness of this viewpoint lies in the fact that it deals only with variables that describe the system without any dedicated (external or internal -type) representation. Subsequently, we illustrate a novel real-time fault-tolerant control (FTC) strategy based on this trajectory standpoint, which does not require an explicit model-based fault diagnosis unit. Instead, the controller is reconfigured directly based on the trajectories generated by the system in real-time, and the given control specifications. In this way, we efficiently excrete the shortcomings that are often seen in model-based fault-tolerant systems. The proposed FTC method is effectively demonstrated on an RLC circuit.  相似文献   

Knowledge transfer in alliances: the moderating role of the alliance type     

Hamid Mazloomi?Khamseh  Dominique?JollyEmail author 《知识管理研究与实践》2014,12(4):409-420

We analyse how the impact of determinants of inter-firm knowledge transfers in alliances can be moderated by the proximity of the resources pooled by partners. Six factors are examined: relative absorptive capacity (RAC), inter-partner trust, cultural distance between allies, knowledge ambiguity, knowledge protection, and the partners’ learning intent. We distinguish alliances mobilizing similar resources by partners (called ‘endogamies’ as allies build on their similarities) from alliances pooling different resources (called ‘exogamies’ as allies build on their differences). We propose that: (a) the impact of RAC on knowledge transfers is reinforced in exogamies, but reduced in endogamies; (b) the knowledge ambiguity and cultural distance effect is less in endogamies than in exogamies; (c) the trust and knowledge protection impact is stronger in exogamies than in endogamies; (d) the learning intent impact on knowledge transfers is similar in endogamies and exogamies.  相似文献   

Union Civil War Patriotic Covers: An Overview     

Steven R. Boyd  Elaine Prange Turney  David W. Hansen 《Journal of American culture (Malden, Mass. : 2003)》1998,21(3):1-12

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The implications of scientific mobility between France and the United States     

Timothy Carlson  Dominique Martin-Rovet 《Minerva》1995,33(3):211-250

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Significant signs: a case study of citation practices in educational research     

Michael Hansen 《International Journal of Research & Method in Education》2016,39(1):74-91

Citations have a central role in the dynamic process of knowledge development and as measures of research performance – yet little is known about their role in educational research or the qualities they are assumed to measure. Based on a citation context analysis, this study shows how a paradigmatic reference within classroom research has been used in 90 articles in educational research journals. Four types of content and four citation functions were identified in the immediate context of the citation symbols. Surprisingly, no critical citations or discussions of the validity of the cited study were found. The results are discussed in relation to the conditions for communication within a field without disciplinary cohesion.  相似文献   

Graduate students as academic writers: writing anxiety,self-efficacy and emotional intelligence     

Margarita Huerta  Patricia Goodson  Mina Beigi  Dominique Chlup 《高等教育研究与发展》2017,36(4):716-729

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Does More Intensive Neonatal Intensive Care Unit Follow-Up Service Result in Better Outcomes? A Cost-Effective Analysis     

Linda D. Goetze  Nancy Immel  Colette M. Escobar  Yvonne Gillette  Daniel Coury  Nancy Hansen 《Early education and development》1993,4(4):275-289

Little is known about the relative cost-effectiveness of the many different types of early intervention services provided to medically fragile infants and their families. This study compared two intensities of services for such infants and their families: (a) a coordinated and comprehensive system of early intervention services initiated prior to discharge from the NICU and designed to transition infants to community-based services were compared with the effects of services (high intensity); and (b) a more traditional hospital follow-up consisting of medical checkups and referrals following discharge (low intensity). High-intensity services resulted in five times more community-based early intervention hours for families and infants when compared with low-intensity services. Annual costs of the high-intensity group were approximately triple the costs of the low-intensity group ($10,814 versus $3,032 per child per year), but there were only a few statistically significant differences on measures of child and family functioning between the groups at 6-, 12-, 18-, and 24months' corrected age. Implications of these findings for research and practice are given.  相似文献   

Discriminant Validity of the Adult Attachment Interview     

Judith A. Crowell  Everett Waters  Dominique Treboux  Elizabeth O'Connor  Christina Colon-Downs  Olga Feider  Barbara Golby  German Posada 《Child development》1996,67(5):2584-2599

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