Anaerobic work and power output during cycle ergometer exercise: effects of bicarbonate loading

Eight trained male cyclists who competed regularly in track races, were studied under control, alkalotic (NaHCO3) and placebo (CaCO3) conditions in a laboratory setting to study the effect of orally induced metabolic alkalosis on 60 s anaerobic work and power output on a bicycle ergometer. Basal, pre- and post-exercise blood samples in the three conditions were analysed for pH, pCO2, pO2, bicarbonate, base excess and lactate. All blood gas measurements were within normal limits at basal levels. There were significant differences in the amount of work produced, and in the maximal power output produced by the cyclists in the experimental condition when compared to the control and placebo conditions (P less than 0.01). The post-exercise pH decreased in all three conditions (P less than 0.05) and post-exercise pCO2 increased significantly in the alkalosis trial (P less than 0.01). In the alkalotic condition, the pre-exercise base excess and HCO3- levels were both higher (P less than 0.05) than the basal levels, suggesting that the bicarbonate ingestion had a significant increase in the buffering ability of the blood. Post-exercise lactate levels were significantly higher (P less than 0.05) after the alkalotic trial when compared to the other two conditions, immediately post-exercise and for the next 3 min. Post-exercise lactate levels were higher than basal or pre-exercise levels (P less than 0.001). This was true immediately post-exercise and for the next 5 min. The results of this study suggest that NaHCO3 is an effective ergogenic aid when used for typically anaerobic exercise as used in this experiment. We feel that this ergogenic property is probably due to the accelerated efflux of H+ ions from the muscle tissue due to increased extracellular bicarbonate buffering.     

Critiques of socio-economic school compositional effects: are they valid?

Abstract

School socio-economic compositional (SEC) effects have been influential in educational research predicting a range of outcomes and influencing public policy. However, some recent studies have challenged the veracity of SEC effects when applying residualised-change and fixed effects models and simulating potential measurement errors in hierarchical regression models. We review the residualised change and fixed effects methods in critical studies and find limitations in their capacity to demonstrate null compositional effects. We show this with an adjusted residualised change model finding significant SEC effects. We show structural equation models can address concerns that measurement errors inflate SEC effects by comparing hierarchical regression models to structural equation models. We find that structural equation models can detect SEC effects free from measurement error. We conclude that the reviewed critiques of SEC effects were due to methods unlikely to detect compositional effects. Future research would benefit from the identification of mediators of SEC effects.     

Secondary Teachers' Interpersonal Behaviour in Singapore,Brunei and Australia: A cross-national comparison

This study investigates the reliability and validity of the Questionnaire on Teacher Interaction (QTI) in three countries: Singapore, Brunei and Australia. The QTI maps student perceptions of interpersonal teacher behaviour and is based on the circumplex Model for Interpersonal Teacher Behaviour (MITB) that investigates the teacher–student relationship in terms of the two dimensions of influence and proximity. Students' perceptions of their teachers in the three countries are also compared. Results show that the QTI scales are represented by two independent dimensions and that scales can be ordered in terms of a circular structure. However, empirical scale locations differ from their theoretical positions as hypothesised by the circumplex model, and among countries. Differences in teacher influence and proximity are also found among the countries.     

Students' Perceptions of Interpersonal Aspects of the Learning Environment

This study examined variables associated with differences in students' perceptions of interpersonal teacher behavior. The perceptions of 3023 students and 74 teachers in 168 classes in seven secondary schools were used in the analyses. Investigating variance at the student, class, teacher and school levels revealed that several variables are significantly related to students' perceptions: student and teacher gender, student and teacher ethnic background, student age and grade, class size, grade level, subject taught and teacher experience. There were interaction effects between some variables, such as student ethnicity and student gender, as well as student and teacher gender. While significant, the amount of variance explained by these was low (around 10%). The outcomes generally confirmed earlier research, although some new effects were found. Perhaps the main result of the study was its verification of the complex and interactive nature of students' perceptions of the learning environment and researchers' understanding of it.     

Risk, error and accountability: improving the practice of school leaders

This paper seeks to explore the notion of risk as an organisational logic within schools, the impact of contemporary accountability regimes on managing risk and then, in turn, to posit a systems-based process of risk management underpinned by a positive logic of risk. It moves through a number of steps beginning with the development of an understanding of risk, the risk society and the logic of risk derived from the seminal work of Douglas (1992, Risk and blame: essays in cultural theory, London: Sage), Beck (1992, Risk society: towards a new modernity. London: Sage) and Giddens (1990, The consequences of modernity. Cambridge: Polity Press). Second, the paper juxtaposes this understanding of risk with the rise of accountability imperatives and an “audit culture” [Strathern (1997) European Review, 5(3), 305–321] in public institutions, including schools. It then moves to consider how a systems-based approach to risk management, drawing on Reason’s (1990, Human Error. New York: Cambridge University Press) model of human error minimisation, could be usefully developed for schools. Such an approach would be built on a positive risk logic which maintains the flexibility, innovativeness and adaptability so necessary in education and avoids the more deleterious effects of many current forms of accountability and risk management which reflect avoidance, conformity and rigidity.     

Providing Space for Teacher Renewal: The role of the facilitator in school-university partnerships

This article uses the process of a teacher renewal partnership programme to explore the role of the university academic as a facilitator of change. Responses to a series of interview questions relating to change were used to explore and examine the dimensions of the facilitator's role. Facilitators report that the role is complex, often uncertain and requires an understanding of the school and its culture and schools' and teachers' previous experiences in professional development programmes. The findings from this article suggest that an effective facilitator creates, for the teachers involved, a space for discussion, reflection and challenge and that this space provides for and legitimates teacher renewal.     

Infants of depressed mothers show "depressed" behavior even with nondepressed adults

To determine whether the "depressed" behavior (e.g., less positive affect and lower activity level) of infants noted during interactions with their "depressed" mothers generalizes to their interactions with nondepressed adults, 74 3-6-month-old infants of "depressed" and nondepressed mothers were videotaped in face-to-face interactions with their mothers and with nondepressed female strangers. "Depressed" mothers and their infants received lower ratings on all behaviors than nondepressed mothers and infants. Although the infants of "depressed" versus nondepressed mothers also received lower ratings with the stranger adult, very few differences were noted between those infants' ratings when interacting with their mother versus the stranger, suggesting that their "depressed" style of interacting is not specific to their interactions with depressed mothers but generalizes to their interactions with nondepressed adults as early as 3 months of age.