Physiological efficiency of constant power output at varying pedal rates

Abstract

The study investigated the absolute and relative (% maximal) physiological demands of constant power output at three pedal rates chosen to incorporate the range used by racing cyclists. Following the assessment of maximal exercise capabilities utilizing a recently developed racing cycle ergometry system, ten highly trained racing cyclists undertook a randomized sequence of work bouts at low (70.0 ± 1.1), medium (94.8 ± 0.8) and high (126.5 ± 1.1) pedal rates per minute at constant power output under an unloaded (free wheel) condition and under a loaded (196.2 ± 8.0 W) condition which demanded approximately 75% VO₂ max. In both the unloaded and loaded conditions absolute cardiorespiratory demands of work at the highest pedal rate were significantly higher than those at the low and medium pedal rates (P<0.05). Similarly, the relative (% max) cardiorespiratory demands of unloaded work at the highest pedalling rate were significantly greater that at low and medium pedal rates (P < 0.05). There were clear, but nonsignificant trends of elevated relative cardiorespiratory demands during loaded work at the highest pedal rate, compared with low and medium pedal rates. Furthermore, net muscular efficiency demonstrated a significant decline (P<0.01) at the highest pedalling rate (21.2%) compared with the medium (24.0%) and low (25.6%) pedalling rates, confirming that metabolic economy of constant power output declined with increased pedalling rate under simulated racing cycling conditions.     

Physics in the primary school: Peer interaction and the understanding of floating and sinking

The paper presents two studies designed to investigate whether, as Piagetian theory would predict, peer interaction can advance the physics understanding of primary school children so long as there is variation in initial viewpoints. The studies were concerned with advancing understanding of floating and sinking, with one focusing on the relevant properties of objects and the other on the relevant properties of fluids. Both studies considered the efficacy of interaction between primary school children whose views varied because they were at different levels of understanding and primary children whose views varied despite being at equivalent levels. In both cases, the children’s pre-to post-test progress was superior to that observed in control children whose interaction had been with peers whose views were similar. However, in contradiction to recent qualifications to Piagetian theory progress from pre- to post-test did not depend on joint advancement within the groups.     

Exploring undergraduates' understanding of photosynthesis using diagnostic question clusters

We present a diagnostic question cluster (DQC) that assesses undergraduates' thinking about photosynthesis. This assessment tool is not designed to identify individual misconceptions. Rather, it is focused on students' abilities to apply basic concepts about photosynthesis by reasoning with a coordinated set of practices based on a few scientific principles: conservation of matter, conservation of energy, and the hierarchical nature of biological systems. Data on students' responses to the cluster items and uses of some of the questions in multiple-choice, multiple-true/false, and essay formats are compared. A cross-over study indicates that the multiple-true/false format shows promise as a machine-gradable format that identifies students who have a mixture of accurate and inaccurate ideas. In addition, interviews with students about their choices on three multiple-choice questions reveal the fragility of students' understanding. Collectively, the data show that many undergraduates lack both a basic understanding of the role of photosynthesis in plant metabolism and the ability to reason with scientific principles when learning new content. Implications for instruction are discussed.     

Time Scales and Academic Excellence

Abstract

While not representative of all students, those who demonstrate a sense of entitlement demand a great deal of instructors' time and energy. Our article places student entitlement in its social context, with specific attention to the prevalence of the consumer mentality, grade inflation, and the self-esteem of the student generation. We then outline several strategies for dealing with entitlement behavior. We suggest that greater clarity in standards and assessment, combined with specific requirements guiding teacher-student interactions and general efforts to resocialize students and faculty, will help to curb these behaviors.