Evidence for data missing at random in youth physical activity monitoring research

This study examined whether or not activity monitor data collected as part of a typical 7-day physical activity (PA) measurement protocol can be expected to be missing at random. A total of 315 participants (9–18 years) each wore a SenseWear Armband monitor for 7 consecutive days. Participants were classified as “compliant” (86 boys and 124 girls) if they had recorded accelerometer data during 70% or more of the predefined awake time (7 AM–10 PM) on four different days; and “non-compliant” (44 boys and 51 girls) when not meeting these criteria. Linear mixed models were used to examine differences in energy expenditure (EE) levels by compliance across 10 different time periods. The results indicated that non-compliant girls were older (13.4 ± 2.9 vs. 12.2 ± 2.5) and taller (156.8 ± 10.3 vs. 152.8 ± 11.3) than their same gender compliant peers (P < .05). Comparisons of EE rates at segmented portions of the day revealed no differences between compliant and non-compliant groups (P ≥ .05). Differences in EE ranged from ?0.32 kcal · kg^?1 · h^?1 (before school time) to 0.62 kcal · kg^?1 · h^?1 (physical education class) in boys and ?0.39 kcal · kg^?1 · h^?1 (transportation from school) to 0.37 kcal · kg^?1 · hour^?1 (recess) in girls. The results showed that compliant and non-compliant individuals differed in a few demographic characteristics but exhibited similar activity patterns. This suggests that data were considered to be missing at random, but additional work is needed to confirm this observation in a representative sample of children using other types of activity monitors and protocols.     

THE CELTIC LANGUAGES AND TELEVISION

The article proposes the subtitling of English television programmes in the Celtic languages and of Celtic language programmes in English in order to serve the Celtic speaking minorities in Britain and to produce an appreciation of the Celtic languages among English speaking viewers. Parallels are drawn between the proposed British bilingual project and those in other countries for deaf viewers and for speakers of minority languages. Results of a survey of English and Welsh viewers are reported, and difficulties such as viewer resistance, cost, etc., of implementing a bilingual subtitling program in Britain are discussed.     

THE LURE OF STATISTICS FOR EDUCATIONAL RESEARCHERS

In this essay David Labaree explores the historical and sociological elements that have made educational researchers dependent on statistics. He shows that educational research as a domain, with its focus on a radically soft and thoroughly applied form of knowledge and with its low academic standing, fits the pattern in which weak professions have been most likely to adopt quantification. One problem with educational researchers' seduction by the quantitative turn is that it deflects attention away from many of the most important issues in the field, which are not easily reduced to standardized quanta. Another is that by adopting this rationalized, quantified, abstracted, statist, and reductionist vision of education, educational policymakers risk imposing reforms that will destroy the local practical knowledge that makes the ecology of the classroom function effectively. Quantification, Labaree suggests, may be useful for the professional interests of educational researchers, but it can be devastating for school and society.     

Pupil guidance: An integral part of teacher education and development in Scotland?

Many schools throughout the UK are experiencing challenging behaviour from pupils and high levels of absence and exclusion as they seek to implement initiatives aimed at raising pupil attainment [National Audit Office (2005). Improving school attendance, London: The Stationery Office]. These initiatives often presuppose that pupils will receive adequate levels of guidance and support to help them make curricular, personal, social, and health decisions. However, little is heard from teachers and students undertaking initial teacher education courses on how they have been prepared for this extended role of supporting increasing diverse student populations; nor do we know how they define guidance/pupil support and integrate this with their concept of the professional role of a teacher. This article presents evidence from a one-year study of pupil support in Scotland commissioned by the Scottish Executive Education Department. The study provided evidence for The National Review of Guidance Provision in Scotland [Scottish Executive (2003). The national review of guidance. Edinburgh: Scottish Executive; Scottish Executive (2005). Happy, safe and achieving their potential. Edinburgh: Scottish Executive]. The study explored the views of all 32 local authorities in Scotland, a sample of students in training in two universities and teachers, headteachers and pupils in eight case study schools, and also a sample of their parents. This article focuses specifically on the findings relating to teachers and students in training. It identifies the ways in which they support pupils and how well they think they have been prepared for that task. Two dominant models of pupil support emerge from these data: an embedded and a specialist approach, and these vary according to school and education sector. Primary school teachers were more likely to embed pupil support into their concept of being teachers, whereas secondary teachers perceived it to be a separate, specialist function, which many were reluctant to undertake. Some implications for teacher education are highlighted.     

Chronic flexibility gains: effect of isometric contraction duration during proprioceptive neuromuscular facilitation stretching techniques

The aim of this study was to assess the effect of to isometic contraction durations during propiceptive neuromuscular facilitation stretching on gains inflexion at the hip. Forty-three women (M age = 20.0 years, SD = 1.3) were assigned to one of three groups: 5-s isometric contraction (5-IC), 10-IC, and control. Flexibility was assessed at baseline and Weeks 3 and 6. Analysis of covariance, controlling for pretest differences, showed a significant interaction, F(2, 33) = 44.1, p < .001. Flexibility was significant lower in the control group relative to the 5-IC and 10-IC groups and in the 5-IC group relative to the 10-IC group at 3 and 6 weeks (3 weeks = 101.2 +/- 1.4 degrees, 114.3 +/- 1.5 degrees, 120.5 +/- 1.3 degrees; 6 weeks = 103.0 +/- 1.4 degrees, 126.1 +/- 1.6 degrees, 133.3 +/- 1.4 degrees for control, 5-IC and 10-IC groups, respectively). A longer contraction time led to greater increases in flexibility.     

Restrictions of the derivatives of positive real functions

Dissipative operators appear in abundance in the study of dynamical systems. In the classical circuit theory they are presented as Positive Real Functions. The coefficients of the Taylor expansion of PRF (driving-point impedance or admittance) must satisfy certain derived inequalities. A method is suggested for obtaining restrictions of the derivative of Positive Real Functions (Dissipative Operators).