Capturing the geography of children’s active and sedentary behaviours at home: the HomeSPACE measurement tool

ABSTRACT

Children spend much of their time at home, indoors and sedentary. This study reports on the development, exploratory factor analysis, validity and reliability of the HomeSPACE Instrument. The instrument assesses features of the home physical environment that influence children’s sedentary behaviour and physical activity, and the family influences that create this environment. The space and equipment audit achieved good to excellent criterion validity and test-retest reliability for equipment, outdoor features and home design measures (Study 1, n?=?36 parents). Family influence scales showed acceptable internal consistency and test-retest reliability (Study 2, n?=?96 parents). Factor analysis highlighted fifteen scales to assess the importance, preferences and supportiveness of the home environment for activity. The HomeSPACE Instrument extends previous tools to provide a valid and reliable assessment of home influences on children’s sedentary behaviour and physical activity, that is adaptable for varying home physical environments.     

Burnt bones and teeth: an experimental study of color,morphology, crystal structure and shrinkage

Burnt osteological materials are one focus of interest in forensic, archaeological, and palaeontological studies. We document the effects of experimental, controlled heating on a sample of modern bones and teeth from sheep and goats. Four aspects of heating specimens to between 20 and 940°C were considered: color, microscopic morphology, crystalline structure and shrinkage. Our results show that changes in both color and microscopic morphology of burnt bones and teeth can be divided into five stages each of which is typical of a particular temperature range, although the stages based on color do not correlate exactly with those based on micromorphology. These stages can be used to determine (1) if specimens of unknown taphonomic history were burnt, and (2) the maximum temperature reached by those specimens. In addition, powder X-ray diffraction studies show that heating causes an increase in the crystal size of hydroxyapatite, the major inorganic component of bones and teeth. This fact in conjunction with the microscopic morphology can be used to confirm deduced heating to 645°C or more. The data on shrinkage are analyzed to yield a polynomial expression that summarizes percentage shrinkage as a function of the maximum temperature reached by bones. Thus, the original size of specimens can be reconstructed within limits since the maximum temperature reached by the bones can be deduced on the basis of color, microscopic morphology and/or powder X-ray diffraction patterns. Finally, because there is a discrepancy between the maximum heating device temperature and the maximum specimen temperature, caution must be exercised in distinguishing between the effects of man made and natural fires.