799 resultados para Scouting (Youth activity)
Resumo:
This thesis is a study of Chinese One Child Generation's digital and social sharing. It examines urban youth grassroots communities, including an urban farmers' community and volunteers in educational camps. These case studies explain the emergence of 'sharism' in reaction to the growing risks in China, such as food safety and environmental degradation emanating from China's rapid economic development, and growing urbanism, globalisation, and consumerism. The new forms of 'sharism' are linked to guanxi (social relations) and connected youth communities, which are made possible by increasing accessibility to digital and networked technologies.
Resumo:
This study assessed the status of bone and cardiovascular health in young, prepubertal females (aged 9 to 11 years) during a school based intervention program involving weight bearing physical activity. A study of 10 months duration was conducted in four primary schools in the Melbourne suburbs. It involved a physical activity group (n=38) and an aged-matched control group (n=33). Baseline data including pubertal status, health-related fitness, bone mass and body composition were obtained pre and post the intervention programme. All children had their bone mineral density monitored. Bone mineral density and body composition measurements were performed by DXA using the Hologic QDR 2000 bone densitometer. At the completion of the program the activity group had accrued significantly greater bone mass at total body, lumbar spine, leg and femoral neck when expressed as BMC or BMD.
Resumo:
The oxides of cobalt have recently been shown to be highly effective electrocatalysts for the oxygen evolution reaction (OER) under alkaline conditions. In general species such as Co3O4 and CoOOH have been investigated that often require an elevated temperature step during their synthesis to create crystalline materials. In this work we investigate the rapid and direct electrochemical formation of amorphous nanostructured Co(OH)2 on gold electrodes under room temperture conditions which is a highly active precursor for the OER. During the OER some conversion to crystalline Co3O4 occurs at the surface, but the bulk of the material remains amorphous. It is found that the underlying gold electrode is crucial to the materials enhanced performance and provides higher current density than can be achieved using carbon, palladium or copper support electrodes. This catalyst exhibits excellent activity with a current density of 10 mA cm-2 at an overpotential of 360 mV with a high turnover frequency of 2.1 s-1 in 1 M NaOH. A Tafel slope of 56 mV dec-1 at low overpotentials and a slope of 122 mV dec-1 at high overpotentials is consistent with the dual barrier model for the electrocatalytic evolution of oxygen. Significantly, the catalyst maintains excellent activity for up to 24 hr of continuous operation and this approach offers a facile way to create a highly effective and stable material.