Effect of chainring ovality on joint power during cycling at different workloads and cadences     

Gerda Strutzenberger  Tobias Wunsch  Josef Kroell  Jacqueline Dastl  Hermann Schwameder 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):97-108

Non-circular chainrings theoretically enhance cycling performance by increasing effective chainring diameter and varying crank velocity, but research has failed to consistently reproduce the benefits in cycling trials. The aim of this study was (1) to investigate the effect of different chainring shapes on sagittal knee joint moment and sagittal lower limb joint powers and (2) to investigate whether alterations are affected by cadence and workload. Fourteen elite cyclists cycled in six conditions (70, 90 and 110 rpm, each at 180 and 300 W), for 2 min each, using three chainrings of different ovalities (1.0–1.215). Kinematic data and pedal forces were collected. For most conditions, only the chainring with the highest ovality (1.215) was characterised by smaller sagittal knee joint moments, smaller relative sagittal knee joint power contribution and larger relative sagittal hip joint power contribution, which suggests a change from maximising efficiency to maximising power production. Effect sizes increased with higher cadences, but not with higher workload. This study has application for athletes, clinicians and sports equipment industry as a non-circular chainring can change joint-specific power generation and decrease knee joint moment, but certain ovality seems to be necessary to provoke this effect.  相似文献   

SKIPing with teachers: an early years motor skill intervention     

Ali Brian  Jacqueline D. Goodway  Jessica A. Logan  Sue Sutherland 《Physical Education & Sport Pedagogy》2017,22(3):270-282

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Sex,Gender and the Sacred: Reconfiguring Religion in Gender History     

Jacqueline R. Devries 《Cultural and Social History》2013,10(5):763-764

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Face-to-face contact in blended learning for intercultural education: the role of teachers     

Roger Austin  Angela Rickard  Jacqueline Reilly 《Irish Educational Studies》2017,36(3):323-340

In societies experiencing or emerging from conflict, teachers often deliver educational programmes designed to build community cohesion. We report on research which examined teachers’ views of the implementation of a programme involving both face-to-face and online contact between pupils. Findings suggest that this blended approach is highly motivational, enhancing online work and relationship building. The research underlines the importance of the political, educational and historical context for work of this sort and the impact this has on the particular blend of online and face-to-face interaction. Implications for policymakers and teachers include value for money and sustainability of blended intercultural education in similar contexts.  相似文献   

The influence of academic culture on quality management system ISO 9001 maintenance within Malaysian universities     

Siti Arni Basir  John Davies  Jacqueline Douglas  Alexander Douglas 《Journal of Higher Education Policy & Management》2017,39(3):320-340

This study investigates the influence of the elements of academic culture on quality management system ISO 9001 maintenance within Malaysian universities. There is a dearth of empirical studies on maintaining ISO 9001, particularly in the higher education context. From the literature review, academic culture was classified according to four elements – academic freedom, individualism, professionalism and collegiality. Two case studies were conducted within Malaysian universities that had been ISO 9001-certified for 5 years. At the time of this research, these two were the only universities that had certification for their entire organisation. (Most organisations gain certification for specific departments). The findings showed that academic freedom, individualism and collegiality had worked against ISO 9001 maintenance, while professionalism had influenced ISO 9001 maintenance both positively and negatively. The opposites of individualism (teamwork) and collegiality (managerialism) had supported ISO 9001 maintenance in one of the cases.  相似文献   

Early contribution of phonological awareness and later influence of phonological memory throughout reading acquisition     

Christelle Nithart  Elisabeth Demont  Marie‐Noëlle Metz‐Lutz  Steve Majerus  Martine Poncelet  Jacqueline Leybaert 《Journal of Research in Reading》2011,34(3):346-363

The acquisition of reading skills is known to rely on early phonological abilities, but only a few studies have investigated the independent contribution of the different steps involved in phonological processing. This 1‐year longitudinal study, spanning the initial year of reading instruction, aimed at specifying the development of phonological discrimination, awareness and various aspects of phonological memory and at assessing their respective contributions to early reading acquisition. Our results show an increase in performance at each phonological processing step, but also suggest a qualitative evolution in their relative importance. Hierarchical regression analyses indicate that reading skills are mainly predicted by phonological awareness measured at the kindergarten stage and, subsequently, by phonological memory abilities measured at the end of first grade. More precisely short‐term memory for serial‐order information seems to contribute to the development of decoding abilities, while phonological knowledge stored in long‐term memory seems to influence word recognition.  相似文献   

Teaching Science Inquiry in Urban Contexts: The Role of Elementary Preservice Teachers’ Beliefs     

Jacqueline Leonard  Joy Barnes-Johnson  Scott Jackson Dantley  Charles Kimber 《The Urban Review》2011,43(1):124-150

This paper reports on a study of elementary preservice teachers’ inquiry-based practices, their efficacy beliefs, and the role beliefs had on two preservice teachers’ practices in urban classrooms. Results show inquiry-based practices can be cultivated through field-based experiences and preservice teachers’ efficacy beliefs, as it relates to practice in urban settings, are malleable. Specifically, personal efficacy beliefs about teaching science improved or were sustained for one cohort of preservice teachers. However, beliefs about students’ ability to learn science, that is outcome beliefs, were less stable. The results of two case studies show that science content knowledge was a factor in preservice teachers’ inquiry-based practices. However, why preservice teachers’ beliefs about student learning declined is less clear. More research is needed, along with follow-up data on teacher induction, to learn how preservice teachers’ beliefs impact urban students’ science education.  相似文献   

The relationship between shoulder alignment and elbow joint angle in cricket fast-medium bowlers     

Roca M  Elliott B  Alderson J  Foster D 《Journal of sports sciences》2006,24(11):1127-1135

The aim of this study was to examine the relationship between shoulder alignment and elbow angle during the delivery action of fast-medium bowlers. The elbow and upper trunk alignment were recorded for 13 high-performance bowlers (mean age 20 years) using a 12-camera Vicon motion analysis system operating at 250 Hz. The three highest velocity trials for "good" and "short" length deliveries were analysed. Results showed that bowlers with a more front-on shoulder alignment at back-foot impact and when the upper arm was horizontal to the ground experienced a significantly greater elbow flexion--extension range when compared with those who had a more side-on orientation at the same point in the delivery action. Bowlers with greater shoulder counter-rotation also recorded higher elbow flexion and subsequently extension during the period from upper arm horizontal to ball release. Shoulder alignment and elbow angles were similar for "short" and "good" length deliveries. It was concluded that bowlers with a more front-on shoulder orientation at back-foot impact demonstrated a higher elbow extension from upper arm horizontal to ball release and are therefore more likely to infringe International Cricket Council elbow tolerance levels, compared with those who adopt a more side-on shoulder orientation at back-foot impact.  相似文献   

The kalamazoo zoo     

Jacqueline Dembar Greene 《Early Childhood Education Journal》1977,5(2):38-39

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Defending Atlanta: Press Reactions to a Movie on the Missing and Murdered Children     

Jacqueline Boles  Phillip W. Davis 《Journal of American culture (Malden, Mass. : 2003)》1988,11(3):61-66

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