Injury and frequency of use of playground equipment in public schools and parks in Brisbane, Australia

Objective: The purpose of this study was to determine the frequency of use of play equipment in public schools and parks in Brisbane, Australia, and to estimate an annual rate of injury per use of equipment, overall and for particular types of equipment. Methods: Injury data on all children injured from playground equipment and seeking medical attention at the emergency department of either of the two children's hospitals in the City of Brisbane were obtained for the years 1996 and 1997. Children were observed at play on five different pieces of play equipment in a random sample of 16 parks and 16 schools in the City of Brisbane. Children injured in the 16 parks and schools were counted, and rates of injury and use were calculated. Results: The ranked order for equipment use in the 16 schools was climbing equipment (3762 uses), horizontal ladders (2309 uses), and slides (856 uses). Each horizontal ladder was used 2.6 times more often than each piece of climbing equipment. Each horizontal ladder was used 7.8 times more than each piece of climbing equipment in the sample of public parks. Slides were used 4.6 times more than climbing equipment in parks and 1.2 times more in public schools. The annual injury rate for the 16 schools and 16 parks under observation was 0.59/100000 and 0.26/100000 uses of equipment, respectively. Conclusions: This study shows that annual number of injuries per standardized number of uses could be used to determine the relative risk of particular pieces of playground equipment. The low overall rate of injuries/100000 uses of equipment in this study suggests that the benefit of further reduction of injury in this community may be marginal and outweigh the economic costs in addition to reducing challenging play opportunities.

Social indicators and comparisons of living standards

Construction of an international index of standards of living, incorporating social indicators and economic output, typically involves scaling and weighting procedures that lack welfare-economic foundations. Revealed preference axioms can be used to make quality-of-life comparisons if we can estimate the representative household's production technology for the social indicators. This method is applied to comparisons of gross domestic product (GDP) and life expectancy for 58 countries. Neither GDP rankings, nor the rankings of the Human Development Index (HDI), are consistent with the partial ordering of revealed preference. A method of constructing a utility-consistent index incorporating both consumption and life expectancy is suggested. (C) 2003 Elsevier Science B.V. All rights reserved.

[0 0 1] zone-axis bright-field diffraction contrast from coherent Ge(Si) islands on Si(0 0 1): Dedicated to Professor Fang-hua Li on the occasion of her 70th birthday

Coherent Ge(Si)/Si(001) quantum dot islands grown by solid source molecular beam epitaxy at a growth temperature of 700degreesC were investigated using transmission electron microscopy working at 300 kV. The [001] zone-axis bright-field diffraction contrast images of the islands show strong periodicity with the change of the TEM sample substrate thickness and the period is equal to the effective extinction distance of the transmitted beam. Simulated images based on finite element models of the displacement field and using multi-beam dynamical diffraction theory show a high degree of agreement. Studies for a range of electron energies show the power of the technique for investigating composition segregation in quantum dot islands. (C) 2003 Elsevier B.V. All rights reserved.

A broad framework for the exploration of South China Sea hydrocarbon deposits in the context of the Trans-ASEAN gas pipeline

Proposals to interconnect the existing gas infrastructure of ASEAN states by a Trans-ASEAN Gas Pipeline carry potential for increased economic development, efficiency and improved energy security in South East Asia - plans to expand the Trans-ASEAN Gas Pipeline to remote hydrocarbon deposits in the South China Sea is subject to contradicting claims of sovereignty by several nations - recent developments in the relationship between ASEAN and China indicate that an interim arrangement is possible, holding great potential to be economically, socially and politically beneficial to the entire region.

The value of dividend imputation tax credits in Australia

A dividend imputation tax system provides shareholders with a credit (for corporate tax paid) that can be used to offset personal tax on dividend income. This paper shows how to infer the value of imputation tax credits from the prices of derivative securities that are unique to Australian retail markets. We also test whether a tax law amendment that was designed to prevent the trading of imputation credits affected their economic value. Before the amendment, tax credits were worth up to 50% of face value in large, high-yielding companies, but Subsequently it is difficult to detect any value at all. (C) 2003 Elsevier B.V. All rights reserved.