Effects of competition, exercise, and mental stress on secretory immunity

It has been suggested that the psychological stress associated with competitive sports events may help to explain the increased susceptibility to respiratory infections due to reductions in secretory immunity. In the current study, we investigated the influence of competitive exercise and psychological stress on secretory immunoglobulin A (s-IgA). Salivary s-IgA and heart rate were measured in 62 healthy young recreationally active men at rest and, in a between-subjects design, following one of four 8-min tasks: mental arithmetic, cycling at workloads of 60 to 180 W (mean = 146 W), mental arithmetic while cycling, or competitive cycling. Mental arithmetic was associated with significant increases in s-IgA concentration (mean = 49 microg.min(-1)) and s-IgA secretion rate (mean = 25 microg.ml(-1)) compared with rest, while mental arithmetic combined with exercise was associated with a significant increase in s-IgA concentration only (mean = 124 microg.min(-1)). In contrast, competitive exercise and exercise alone did not influence s-IgA concentration or secretion rate. Heart rate increased modestly to mental arithmetic (mean = 7 beats.min(-1)) and substantially, and similarly, to the three exercise tasks (mean = 56(62 beats.min(-1)). The hypothesis that the psychological stress of competitive exercise contributes to increased susceptibility to infection via reductions in s-IgA requires further investigation.     

Assessing students' ability to trace matter in dynamic systems in cell biology

College-level biology courses contain many complex processes that are often taught and learned as detailed narratives. These processes can be better understood by perceiving them as dynamic systems that are governed by common fundamental principles. Conservation of matter is such a principle, and thus tracing matter is an essential step in learning to reason about biological processes. We present here multiple-choice questions that measure students' ability and inclination to trace matter through photosynthesis and cellular respiration. Data associated with each question come from students in a large undergraduate biology course that was undergoing a shift in instructional strategy toward making fundamental principles (such as tracing matter) a central theme. We also present findings from interviews with students in the course. Our data indicate that 1) many students are not using tracing matter as a tool to reason about biological processes, 2) students have particular difficulties tracing matter between systems and have a persistent tendency to interconvert matter and energy, and 3) instructional changes seem to be effective in promoting application of the tracing matter principle. Using these items as diagnostic tools allows instructors to be proactive in addressing students' misconceptions and ineffective reasoning.     

Pre-service teachers’ TPACK competencies for spreadsheet integration: insights from a mathematics-specific instructional technology course

This article explored the impact of strategies applied in a mathematics instructional technology course for developing technology integration competencies, in particular in the use of spreadsheets, in pre-service teachers. In this respect, 104 pre-service mathematics teachers from a teacher training programme in Ghana enrolled in the mathematics instructional technology course for one semester. Strategies applied in designing the course were: aligning theory and practice, collaborative design, learning technology by design, modelling how to use technology and scaffolding authentic technology experiences. The pre-service teachers’ technology integration competencies were assessed through analysis of lesson plans and lesson observations, their self-reported technological pedagogical content knowledge and attitudes towards technology. Findings show that pre-service teachers’ technology integration competencies improved after participation in the course. All strategies were considered important, but in particular, scaffolding authentic technology experiences including feedback from teaching try-outs made significant contributions to the pre-service teachers’ developed technology integration competencies. The study provides guidelines that can serve as a benchmark for implementing strategies in the design of a subject-specific teacher education programme in preparing pre-service teachers to integrate technology in teaching.