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11.
Herbert W. Marsh Julien P. Chanal Philippe G. Sarrazin 《Journal of sports sciences》2013,31(1):101-111
Abstract A large body of research in support of the reciprocal effects model of causal ordering demonstrates that prior academic self-concept predicts subsequent academic achievement beyond what can be explained in terms of prior achievement. Here we evaluate the generalizability of this support for the reciprocal effects model to a physical activity context in which achievement is reflected in gymnastics skills on a standardized gymnastics performance test evaluated by expert judges. Based on the responses of 376 adolescents collected at the start (T1) and end (T2) of a gymnastics training programme, there is support for a reciprocal effects model in which there are significant paths leading from both T1 gymnastics self-concept to T2 gymnastics skills and from T1 gymnastics skills to T2 self-concept. Although there were gender and age effects (girls and older participants had better gymnastics skills, boys had higher self-concepts), multiple group structural equation models indicated that support for the reciprocal effects model generalized over responses by boys and girls. In summary, self-concept and performance are both determinants and consequences of each other. 相似文献
12.
Virginie Nicaise Julien E. Bois Stuart J. Fairclough Anthony J. Amorose Geneviève Cogérino 《Journal of sports sciences》2013,31(8):915-926
Abstract In this study, we examined the perceptions of physical education (PE) teachers' feedback patterns with female and male high school students (n = 325). Eight physical education teachers (4 females and 4 males) were involved. We examined (a) whether teachers' feedback was perceived differently by boys and girls, and how the sex of the teacher influenced these perceptions, and (b) the effects of types of feedback (praise, no response-successful, encouragement, technical information, criticism, no response-unsuccessful, and teacher's invested time) on students' perceived competence, effort, enjoyment, and their PE performance. A multivariate analysis revealed an interaction between teacher and student gender on perceptions of teacher feedback. Hierarchical regression analyses highlighted that the perceived feedback significantly predicted students' perceptions of competence (ΔR 2 = 0.088), effort (ΔR 2 = 0.119), enjoyment (ΔR 2 = 0.085), and their PE performance (ΔR 2 = 0.039) after accounting for the gender of the students and teachers and the students' initial PE performance. The perceptions of praise and teachers' invested time were positively linked with the dependent variables, whereas encouragement and technical information and criticism were negatively linked. The findings are discussed in terms of teaching effectiveness and gender equity. 相似文献
13.
Julien Caunter Stanley J. Solomon Jerry Lewis William Bayer Alan Rosenthal 《Communication Booknotes Quarterly》2013,44(4):4-6
Julien Caunter's How to Make Movie Magic in Amateur Films (Philadelphia: Chilton Books, 1971---price not known) Stanley J. Solomon The Film Idea (New York: Harcourt, Brace, Javanovich, March 1972---$4.95 paper) Jerry Lewis' The Total Filmmaker (New York: Random House, 1971---$6.95) William Bayer's Breaking Through, Selling Out, Dropping Dead, and Other Notes on Film Making (New York: Macmillan, 1971---$5.95) Alan Rosenthal (ed.) The New Documentary in Action: A Casebook in Film Making (Berkeley: University of California Press, 1971---$11.95) 相似文献
14.
Reliability of unipodal and bipodal counter movement jump landings in a recreational male population
Cédric Schwartz Bénédicte Forthomme Julien Paulus Jean-François Kaux Olivier Brüls Vincent Denoël 《European Journal of Sport Science》2017,17(9):1143-1152
Movement patterns during landing have been suggested to be related to injury risk. The purpose of this study was to determine the inter-session reliability of kinematic variables and ground reaction forces during landing in a population of male recreational athletes after a counter movement jump. Both unipodal and bipodal landings were evaluated. Furthermore, the possibility to improve landing reliability with a verbal instruction was also studied. Twenty-four male volunteers with no history of lower extremity trauma were randomly assigned to two groups (with and without verbal landing instruction). An optoelectronic 3D system and force plates were used to measure the lower limb joint angles and the ground reaction forces during landing. Intraclass correlation values show moderate to excellent inter-session reliability for the bipodal task (ICC average: 0.80, range: 0.46–0.97) and poor to excellent reliability for the unipodal task (ICC average: >0.75, range: 0.20–0.95). However, large standard errors of measurement values at the ankle joint at impact (27.6?±?11.5°) and for the vertical ground reaction forces (394?±?1091 N) show that some variables may not be usable in practice. The verbal instruction had a negative effect on the reliability of unipodal landing but improved the reliability of bipodal landing. These findings show that the reliability of a landing task is influenced by its motor complexity as well as the instruction given to the subject. 相似文献
15.
Julien Marchalot Jean-Fran?ois Chateaux Magalie Faivre Hichem C. Mertani Rosaria Ferrigno Anne-Laure Deman 《Biomicrofluidics》2015,9(5)
Enrichment of rare cell populations such as Circulating Tumor Cells (CTCs) is a critical step before performing analysis. This paper presents a polymeric microfluidic device with integrated thick Carbon-PolyDimethylSiloxane composite (C-PDMS) electrodes designed to carry out dielectrophoretic (DEP) trapping of low abundance biological cells. Such conductive composite material presents advantages over metallic structures. Indeed, as it combines properties of both the matrix and doping particles, C-PDMS allows the easy and fast integration of conductive microstructures using a soft-lithography approach while preserving O2 plasma bonding properties of PDMS substrate and avoiding a cumbersome alignment procedure. Here, we first performed numerical simulations to demonstrate the advantage of such thick C-PDMS electrodes over a coplanar electrode configuration. It is well established that dielectrophoretic force (FDEP) decreases quickly as the distance from the electrode surface increases resulting in coplanar configuration to a low trapping efficiency at high flow rate. Here, we showed quantitatively that by using electrodes as thick as a microchannel height, it is possible to extend the DEP force influence in the whole volume of the channel compared to coplanar electrode configuration and maintaining high trapping efficiency while increasing the throughput. This model was then used to numerically optimize a thick C-PDMS electrode configuration in terms of trapping efficiency. Then, optimized microfluidic configurations were fabricated and tested at various flow rates for the trapping of MDA-MB-231 breast cancer cell line. We reached trapping efficiencies of 97% at 20 μl/h and 78.7% at 80 μl/h, for 100 μm thick electrodes. Finally, we applied our device to the separation and localized trapping of CTCs (MDA-MB-231) from a red blood cells sample (concentration ratio of 1:10). 相似文献
16.
Matthias Gilgien Jörg Spörri Julien Chardonnens Josef Kröll Philippe Limpach Erich Müller 《Journal of sports sciences》2015,33(9):960-969
In the sport of alpine skiing, knowledge about the centre of mass (CoM) kinematics (i.e. position, velocity and acceleration) is essential to better understand both performance and injury. This study proposes a global navigation satellite system (GNSS)-based method to measure CoM kinematics without restriction of capture volume and with reasonable set-up and processing requirements. It combines the GNSS antenna position, terrain data and the accelerations acting on the skier in order to approximate the CoM location, velocity and acceleration. The validity of the method was assessed against a reference system (video-based 3D kinematics) over 12 turn cycles on a giant slalom skiing course. The mean (± s) position, velocity and acceleration differences between the CoM obtained from the GNSS and the reference system were 9 ± 12 cm, 0.08 ± 0.19 m · s-1 and 0.22 ± 1.28 m · s-2, respectively. The velocity and acceleration differences obtained were smaller than typical differences between the measures of several skiers on the same course observed in the literature, while the position differences were slightly larger than its discriminative meaningful change. The proposed method can therefore be interpreted to be technically valid and adequate for a variety of biomechanical research questions in the field of alpine skiing with certain limitations regarding position. 相似文献
17.
The rapid rise of MOOCs (Massive Open Online Courses) signals a shift in the ways in which digital teaching and learning are engaged in and understood. Drawing upon a comprehensive search of nine leading academic databases, this paper examines the initial phase of MOOC scholarship (2009–2013), and offers an analysis of these empirical studies that conceptualizes themes in MOOC scholarship and locates them within a chronological framework. Two key phases of scholarship about MOOCs are identified, each with associated research imperatives and themes. Phase One: Connectivist MOOCs, Engagement and Creativity 2009–2011/2012. Themes of Phase One include: development of Connectivism as a learning theory, and technological experimentation and innovation in early cMOOCs. Phase Two: xMOOCs, Learning Analytics, Assessment, and Critical Discourses about MOOCs 2012–2013. Themes of Phase Two include: the rise of xMOOCs, further development of MOOC pedagogy and platforms, growth of learning analytics and assessment, and the emergence of a critical discourse about MOOCs. 相似文献
18.
We discuss the ability to perform fluorescent immunocytochemistry, following cell fixation, using a microfluidic array of primary, nonadherent, single CD34+ stem cells. The technique requires small cell samples and proceeds with no cell loss, making it well-suited to monitoring these rare patient-derived cells. The chip allows us to correlate live cell dynamics across arrays of individual cells with post-translational modifications of intracellular proteins, following their exposure to drug treatments. Results also show that due to the microfluidic environment, the time scale of cell fixation was significantly reduced compared to conventional methods, leading to greater confidence in the status of the protein modifications studied. 相似文献
19.
Self-belief does make a difference: a reciprocal effects model of the causal ordering of physical self-concept and gymnastics performance 总被引：2，自引：0，他引：2
A large body of research in support of the reciprocal effects model of causal ordering demonstrates that prior academic self-concept predicts subsequent academic achievement beyond what can be explained in terms of prior achievement. Here we evaluate the generalizability of this support for the reciprocal effects model to a physical activity context in which achievement is reflected in gymnastics skills on a standardized gymnastics performance test evaluated by expert judges. Based on the responses of 376 adolescents collected at the start (T1) and end (T2) of a gymnastics training programme, there is support for a reciprocal effects model in which there are significant paths leading from both T1 gymnastics self-concept to T2 gymnastics skills and from T1 gymnastics skills to T2 self-concept. Although there were gender and age effects (girls and older participants had better gymnastics skills, boys had higher self-concepts), multiple group structural equation models indicated that support for the reciprocal effects model generalized over responses by boys and girls. In summary, self-concept and performance are both determinants and consequences of each other. 相似文献
20.
A Canadian national survey of 788 library staff doing instructional work revealed that most participants expected to be doing some teaching in their workplaces, and the largest proportion of participants have been teaching for more than 10 years. Most instruction continues to take the form of short presentations to groups of learners. On the whole, preparatory experiences are informal—on-the-job experience, reading professional literature, and attending workshops. The majority of respondents identify instructional work as integral to their professional identity, but nearly one-third see this work as a duty or expectation, and a small proportion view it as an imposition. The study results have implications for design of programs that prepare library staff for the workplace, and for library managers who need to support effective instructional practice. 相似文献