A calibration protocol for population-specific accelerometer cut-points in children

PurposeTo test a field-based protocol using intermittent activities representative of children\u27s physical activity behaviours, to generate behaviourally valid, population-specific accelerometer cut-points for sedentary behaviour, moderate, and vigorous physical activity.MethodsTwenty-eight children (46% boys) aged 10&ndash;11 years wore a hip-mounted uniaxial GT1M ActiGraph and engaged in 6 activities representative of children\u27s play. A validated direct observation protocol was used as the criterion measure of physical activity. Receiver Operating Characteristics (ROC) curve analyses were conducted with four semi-structured activities to determine the accelerometer cut-points. To examine classification differences, cut-points were cross-validated with free-play and DVD viewing activities.ResultsCut-points of &le;372, &gt;2160 and &gt;4806 counts&bull;min&minus;1 representing sedentary, moderate and vigorous intensity thresholds, respectively, provided the optimal balance between the related needs for sensitivity (accurately detecting activity) and specificity (limiting misclassification of the activity). Cross-validation data demonstrated that these values yielded the best overall kappa scores (0.97; 0.71; 0.62), and a high classification agreement (98.6%; 89.0%; 87.2%), respectively. Specificity values of 96&ndash;97% showed that the developed cut-points accurately detected physical activity, and sensitivity values (89&ndash;99%) indicated that minutes of activity were seldom incorrectly classified as inactivity.ConclusionThe development of an inexpensive and replicable field-based protocol to generate behaviourally valid and population-specific accelerometer cut-points may improve the classification of physical activity levels in children, which could enhance subsequent intervention and observational studies.<br /

Scaffolding in teacher-student interaction: a decade of Research

Although scaffolding is an important and frequently studied concept, much discussion exists with regard to its conceptualizations, appearances, and effectiveness. Departing from the last decade’s scaffolding literature, this review scrutinizes these three areas of scaffolding. First, contingency, fading, and transfer of responsibility are discerned in this review as the three key characteristics of scaffolding. Second, an overview is presented of the numerous descriptive studies that provided narratives on the appearances of scaffolding and classifications of scaffolding strategies. These strategies are synthesized into a framework for analysis, distinguishing between scaffolding means and intentions. Third, the small number of effectiveness studies available is discussed and the results suggest that scaffolding is effective. However, more research is needed. The main challenge in scaffolding research appears to be its measurement. Based on the encountered and described measurement problems, suggestions for future research are made

Effect of company size on potential for REACH compliance and selection of safer chemicals

REACH represents a global paradigm shift in chemical regulation, and it has introduced a new, complex regulatory process to which chemical producers and users throughout supply chains must adapt. This paper presents results of survey research to illustrate whether and how the business members of a large Scandinavian trade organization understand and comply with REACH. It also explores how these businesses obtain information about the chemicals they use in their products, and whether they feel that the information they have is sufficient to meet their needs. In addition, the paper describes how business size affects these issues. The survey results show that, at the time of this study, many small and medium-sized enterprises (SMEs) and a number of larger firms were unaware of REACH. Survey results consistently showed that the size of a company is an important factor in both understanding of and compliance with REACH, with respondents from large firms having a better grasp of REACH and its implications than smaller companies. An effective implementation of REACH will require, at the most basic level, more attention to educating EU companies, especially smaller ones, on how and why REACH applies to them. Survey respondents who were aware of REACH and its applicability to their firms also reported the types of support they needed in order to better understand and comply with the regulation, with nearly 40% of all respondents expressing a need for help with data systems or tools to manage REACH requirements and communicate REACH requirements to suppliers and customers. Many companies reported needing more information from their suppliers on chemical composition and related health impacts of materials and products. Ensuring that this information is readily available throughout supply chains is essential to reducing the negative impacts of chemicals and products on human health and the environment