Adolescent physical activity levels: discrepancies with accelerometer data analysis

This study investigated the effects of epoch length and cut point selection on adolescent physical activity intensity quantification using vertical axis and vector magnitude (VM) measurement with the ActiGraph GT3X+ accelerometer. Four hundred and nine adolescents (211 males; 198 females) aged 12–16 years of age wore accelerometers during waking hours. The GT3X+ acceleration counts were reintegrated into 1, 5, 15, 30 and 60 s epoch lengths for both vertical axis and VM counts. One cut point was applied to vertical axis counts and three different cut points were applied to VM counts for each epoch length. Significant differences (P < 0.01) in mean total counts per day were observed between vertical axis and VM counts, and between epoch lengths for VM only. Differences in physical activity levels were observed between vertical and VM cut points, and between epoch lengths across all activity intensities. Our findings illustrate the magnitude of differences in physical activity outcomes that occur between axis measurement, cut points and epoch length. The magnitude of difference across epoch length must be considered in the interpretation of accelerometer data and seen as a confounding variable when comparing physical activity levels between studies.     

Research,Development and Tacit Capability in the Education System

The relevance gap between educational practice and research is often seen as a methodological problem. But communicative and social issues are also vitally important. The idea of tacit capability, from recent work in economics on research and development, characterises the knowledge which can be acquired by and attributed to an organisation as a conversational whole. (Schön's idea of reflective practice is unhelpfully monological.) I interpret and validate this idea in the light of Habermas’ account of communicative action. I use it to explore social problems in the relation between educational practice and research and suggest solutions modelled on enlightened industrial practice in Europe.     

Creating a model to examine motivation for sustained engagement in online communities

This paper considers factors that influenced long-term engagement in an online community. It draws on a case study of a 6 year online collaboration amongst a group of European teachers. The email interchange between these teachers was, with their agreement, saved and used as research data; intensive group interviews were also conducted, involving all the participants in the online group. Dynamic motivation models and Csikszentmihalyi’s concept of motivational flow were used to create a theoretical framework to analyse the email interchanges and group interview data so as to build an understanding of the teachers’ commitment to the online community. As a result of the analysis, the existing theoretical models were modified to produce a new combined model. This incorporates ideas grounded in the participants’ reasons for their sustained engagement in the collaboration. This combined model could provide a basis for planning future virtual interactions and for assessing their sustainability.     

Neighborhood Physical Activity Opportunity: A Multilevel Contextual Model

Purpose: The aims of this study were to analyze the intensity of emotions (positive, negative, or ambiguous) produced when players took part in traditional games with a different social structure and to examine the explanations given by those participants for these emotional experiences. Method: Participants (N = 556) were recruited from 4 Spanish universities. After taking part in each of the games, they were asked to complete the Games and Emotions Questionnaire to indicate the intensity of their emotional experiences and to explain what, in their view, had led to the strongest emotion felt. Results: The application of a mixed-methods approach identified statistically significant differences in relation to 3 variables. These were (a) the type of emotion, (b) motor domain, and (c) type of result (win, loss, and noncompetitive). The intensity of positive emotions was higher in cooperative games and lower in individual games. Comments referring to negative emotions were more frequent as the social structure of games became more complex (minimal presence of individual games and predominance of cooperation-opposition games). Winning was associated with the highest intensity ratings of positive and ambiguous emotions, whereas being defeated produced the highest values for negative emotions. The intensity ratings for negative emotions were lower in noncompetitive games than in games where players lost. Conclusion: The results confirm that traditional games can play a key role in relation to the emotional facets of physical education.     

Using the Internet in teaching: the views of practitioners (A survey of the views of secondary school teachers in Sheffield, UK)

A questionnaire was generated from the results of a series of interviews at The City School one of the 27 state secondary schools in Sheffield. In October 2002, it was sent out to 499 Heads of Department at the remaining 26 state secondary schools. Responses were received from 188 teachers, ranging in age from 24 to 60 years old. The purpose of the questionnaire was to gain information about teachers’ views of the Internet and its usefulness as an educational tool. Nearly 85% of teachers acquired their Internet skills informally (self‐taught, learned from friends/colleagues, etc), rather than on a taught course. Despite this, most of the respondents were confident of their ability to use the Internet, with the most confident users being young teachers of technical subjects. However, there was a widespread perception (particularly amongst women teachers) that students are more competent users of the Internet than are teachers. Older teachers were more likely to feel under pressure to use the Internet than their younger colleagues. Only about a third of teachers agreed with the statement “I often use the Internet with classes.” Responses varied significantly according to school and subject. There was strong support, however, for the suggestion that the Internet is a valuable source of learning and teaching materials.     

Microbial control of diamondback moth, Plutella xylostella L.(Lepidoptera: Yponomeutidae) using bacteria (Xenorhabdus nematophila) and its metabolites from the entomopathogenic nematode Steinernema carpocapsae

Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X. nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.     

Evolution and revolution: gauging the impact of technological and technical innovation on Olympic performance

A number of studies have pointed to a plateauing of athletic performance, with the suggestion that further improvements will need to be driven by revolutions in technology or technique. In the present study, we examine post-war men's Olympic performance in jumping events (pole vault, long jump, high jump, triple jump) to determine whether performance has indeed plateaued and to present techniques, derived from models of human growth, for assessing the impact of technological and technical innovation over time (logistic and double logistic models of growth). Significantly, two of the events involve well-documented changes in technology (pole material in pole vault) or technique (the Fosbury Flop in high jump), while the other two do not. We find that in all four cases, performance appears to have plateaued and that no further "general" improvement should be expected. In the case of high jump, the double logistic model provides a convenient method for modelling and quantifying a performance intervention (in this case the Fosbury Flop). However, some shortcomings are revealed for pole vault, where evolutionary post-war improvements and innovation (fibre glass poles) were concurrent, preventing their separate identification in the model. In all four events, it is argued that further general growth in performance will indeed need to rely predominantly on technological or technical innovation.