Is passive drag dependent on the interaction of kayak design and paddler weight in flat-water kayaking?     

Beatriz B. Gomes  Filipe A.V. Conceição  David R. Pendergast  Ross H. Sanders  Mário A.P. Vaz  João Paulo Vilas-Boas 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):394-403

Abstract

Drag is one of the major factors that influences kayaking performance. To focus on the drag of the kayak’s hull shape and the paddlers’ weight per se, the passive drag (D_p) was measured on a flat-water sprint course for one paddler with added weights. D_p was measured by an electromechanical towing device using a load cell, at incremental and constant velocities from 2.78 to 5.56 m/s. Three kayaks of different sizes and shapes (Nelo® K1 Quattro-M, ML, and L) were used and the paddlers’ body weight was adjusted with weights so the total paddler weight in the kayak was 65, 75, and 85 kg. The mean D_p increased by the power function of D = kvⁿ (mean R² = .990; SD .006). The D_p went from 21.37?±?1.29 N at 2.78 m/s to 89.32?±?6.43 N at 5.56 m/s. For the two lighter weighted kayaks (65 and 75 kg), the lowest D_p was observed with different kayak sizes (M, ML, or L) depending on the target velocity. The manufacturers suggest that paddlers should select a kayak size according to their body weight to minimise drag; however, the results of this study suggest that target velocities, and thus competition distance should also be factored into kayak selection.  相似文献   

Psychologists’ dilemmas in career counselling practice     

Paulo Miguel Cardoso  Maria Céu Taveira  Constan?a Sacadura Biscaia  Maria Gra?a Santos 《International Journal for Educational and Vocational Guidance》2012,12(3):225-241

In this study, we explored main dilemmas psychologists face in career counselling in two main professional settings: employment and education. Participants included 24 experienced Portuguese psychologists, working in employment (n?=?14) and educational (n?=?10) settings. We used consensual qualitative research to conduct and analyse semi-structured interviews. Results revealed dilemmas?? in five domains: neutrality, assessment, dual loyalty, role boundaries, and confidentiality, with the typical dilemma in the domain of neutrality. Differences between groups were found in the domains of dual loyalty and role boundaries.  相似文献   

A reinterpretation of institutional transformations in European higher education: strategising pluralistic organisations in multiplex environments   总被引：1，自引：0，他引：1  

Nicoline Frølich  Jeroen Huisman  Stig Slipersæter  Bjørn Stensaker  Paulo Charles Pimentel Bótas 《Higher Education》2013,65(1):79-93

The paper draws on institutional theory with special attention to recent contributions that aim at developing its micro-foundations. We address the question of how individual higher education institutions deal with institutional pluralism. We develop an analytical framework inspired by institutional theory, the sensemaking perspective in organisation theory and strategy-as-practice to connect the macro-transformation processes of the organisational field and the micro-processes of organisational strategising.  相似文献   

Book reviews     

Hans Freudenthal  Konrad Jacobs  Paulo Abrantes 《Educational Studies in Mathematics》1986,17(3):323-333

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Physiological responses at the lactate-minimum-intensity with and without prior high-intensity exercise     

Alessandro Moura Zagatto  Johnny Padulo  Adelino Ramos Sanchez da Silva  Paulo de Tarso Guerrero Müller  Willian Eiji Miyagi  Claudio Alexandre Gobatto 《Journal of sports sciences》2016,34(21):2106-2113

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Are the new starting block facilities beneficial for backstroke start performance?     

Karla de Jesus  Kelly de Jesus  J. Arturo Abraldes  Alexandre Igor Araripe Medeiros  Ricardo J. Fernandes  João Paulo Vilas-Boas 《Journal of sports sciences》2016,34(9):871-877

We aimed to analyse the handgrip positioning and the wedge effects on the backstroke start performance and technique. Ten swimmers completed randomly eight 15 m backstroke starts (four with hands on highest horizontal and four on vertical handgrip) performed with and without wedge. One surface and one underwater camera recorded kinematic data. Standardised mean difference (SMD) and 95% confidence intervals (CI) were used. Handgrip positioning did not affect kinematics with and without wedge use. Handgrips horizontally positioned and feet over wedge displayed greater knee angular velocity than without it (SMD = ?0.82; 95% CI: ?1.56, ?0.08). Hands vertically positioned and feet over wedge presented greater take-off angle (SMD = ?0.81; 95% CI: ?1.55, ?0.07), centre of mass (CM) vertical positioning at first water contact (SMD = ?0.97; 95% CI: ?1.87, ?0.07) and CM vertical velocity at CM immersion (SMD = 1.03; 95% CI: 0.08, 1.98) when comparing without wedge use. Swimmers extended the hip previous to the knee and ankle joints, except for the variant with hands vertically positioned without wedge (SMD = 0.75; 95% CI: ?0.03, 1.53). Swimmers should preserve biomechanical advantages achieved during flight with variant with hands vertically positioned and wedge throughout entry and underwater phase.  相似文献   

EDUCATION,LIBERATION AND THE CHURCH   总被引：1，自引：0，他引：1  

Paulo Freire 《Religious education (Chicago, Ill.)》2013,108(4):524-545

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Improving teaching and learning of computer programming through the use of the Second Life virtual world     

Micaela Esteves  Benjamim Fonseca  Leonel Morgado  Paulo Martins 《British journal of educational technology : journal of the Council for Educational Technology》2011,42(4):624-637

The emergence of new technologies such as three‐dimensional virtual worlds brings new opportunities for teaching and learning. We conducted an action research approach to the analysis of how teaching and learning of computer programming at the university level could be developed within the Second Life virtual world. Results support the notion that it is possible to use this environment for better effectiveness in the learning of programming. The main results are the identification of problems hampering the teacher's intervention in this virtual world and the detection of solutions for those problems that were found effective to the success in using this environment for teaching/learning computer programming.  相似文献   

Cardiac vagal regulation and early peer status     

Graziano PA  Keane SP  Calkins SD 《Child development》2007,78(1):264-278

A sample of 341 5 (1/2) -year-old children participating in an ongoing longitudinal study was the focus of a study on the relation between cardiac vagal regulation and peer status. To assess cardiac vagal regulation, resting measures of respiratory sinus arrhythmia (RSA) and RSA change (suppression) to 3 cognitively and emotionally challenging tasks were derived. Results indicated that vagal regulation was positively associated with peer status. In addition, mediational analyses revealed that the relation between vagal regulation and peer status was mediated through better social skills for girls and better social skills and fewer behavior problems for boys. These findings are discussed in terms of the role of vagal regulation in the facilitation of children's positive social behavior.  相似文献   

Foreign language pronunciation skills and musical aptitude: A study of Finnish adults with higher education     

Riia Milovanov  Päivi Pietilä  Mari Tervaniemi  Paulo A.A. Esquef 《Learning and individual differences》2010,20(1):56-60

The main aim of this study was to examine second language production and discrimination skills in the light of musical aptitude. Our study was conducted in university settings in south-western Finland. English was used as a model for the second language due to its popularity among young adults. There were three types of tests used in this study: a pronunciation test, a phonemic listening discrimination task, and the Seashore test as an index of the musical aptitude. All the participants performed equally well in the phonemic listening discrimination task. However, the participants with higher musical aptitude were able to pronounce English better than the participants with less musical aptitude. The results, therefore, imply that musical and linguistic skills are interconnected.  相似文献