Validity of a device designed to measure braking power in bicycle disc brakes

Real-world cycling performance depends not only on exercise capacities, but also on efficiently traversing the bicycle through the terrain. The aim of this study was to determine if it was possible to quantify the braking done by a cyclist in the field. One cyclist performed 408 braking trials (348 on a flat road; 60 on a flat dirt path) over 5 days on a bicycle fitted with brake torque and angular velocity sensors to measure brake power. Based on Newtonian physics, the sum of brake work, aerodynamic drag and rolling resistance was compared with the change in kinetic energy in each braking event. Strong linear relationships between the total energy removed from the bicycle-rider system through braking and the change in kinetic energy were observed on the tar-sealed road (r² = 0.989; p < 0.0001) and the dirt path (r² = 0.952; p < 0.0001). T-tests revealed no difference between the total energy removed and the change in kinetic energy on the road (p = 0.715) or dirt (p = 0.128). This study highlights that brake torque and angular velocity sensors are valid for calculating brake power on the disc brakes of a bicycle in field conditions. Such a device may be useful for investigating cyclists’ ability to traverse through various terrains.     

Book Reviews

A Century of Science Publishing: A Collection of Essays Edited by E.H. Fredriksson Amsterdam: IOS Press, 2001. US$49/€44/€31 A User's Guide to Copyright, 6th edn Michael Flint, Nick Fitzpatrick and Clive Thorne Tottell Publishing, 2006, ISBN 1845920686, 639 pp., paperback, £78 Publishing Law, 3rd edn Hugh Jones and Christopher Benson Taylor and Francis, 2006 ISBN 0 415 38427 3 Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers , 7th edn Style Manual Committee, Council of Science Editors Council of Science Editors in cooperation with The Rockefeller University Press, 2006, xvi + 659 pp. Hardback. ISBN 0‐9779665‐0‐X The Trouble with Medical Journals Richard Smith Royal Society of Medicine, 2006, ISBN 1 85315 673 6, 292pp., £19.95     

Peer‐mediated interventions with elementary and secondary school students with emotional and behavioural disorders: a literature review

Peer‐mediated interventions (PMIs) have been shown to be effective for increasing adaptive social and academic behaviours of children and youth. Although PMI efficacy is generally well supported, there have been relatively few published intervention studies that focus on elementary, middle and high school students with emotional and behavioural disorders (EBD). The present review examines selected empirical literature in order to identify characteristics and relative efficacy of PMI. Findings of 12 peer‐reviewed journal papers including research designs and outcomes were examined. Results provide support for the efficacy of PMI for improving behavioural and social skills of students with EBD. Recommendations include further research on PMI for high school students and longitudinal research of PMI.     

Hormone receptors

It is characteristic of hormones that they can elicit full response in their target cells at exceedingly low concentrations. Further, although they are individually very specific in their action they co-ordinate the activity of the body as a whole. Recent research has begun to reveal a mechanism of action of hormones, at the molecular level, that satisfactorily explains their characterisitics.     

Use of problem-based learning in the teaching and learning of horticultural production

Purpose: Problem-based learning (PBL), a relatively novel teaching and learning process in horticulture, was investigated. Proper application of PBL can potentially create a learning context that enhances student learning. Design/Methodology/Approach: Students worked on two complex ill-structured problems: (1) to produce fresh baby greens for a 4-week catering event and (2) to produce seedlings for a grower. Data collected were analyzed by the concurrent method and presented as case studies. Findings: Students developed positive attitudes through active engagement. Their presentations and reports demonstrated leadership roles, critical thinking and conflict management. Practical professional, social and affective skills were developed through production of 5?kg baby greens, and 2500 vegetable seedlings. Successes and limitations were identified. Theoretical Implication: The quality of the PBL problem is critical for the stimulation and elaboration of prior knowledge, development of epistemic curiosity and the relevant semantic framework. These are motivators that inspire effective learning. Practical Implication: Cognitive and emotional intelligence skills are realized by trusting the PBL process, identifying enhancers and inhibitors. Enhancement of creativity, social and employability skills manifest through challenges that help to develop for the ‘whole’. Originality/Value: In the horticulture industry, stakeholders interact with each other and the agro-ecological system. Consequently, competencies in production and emotional intelligence are invaluable.