Public investment and the risk premium for equity

Analysis of the equity premium puzzle has focused on private-sector capital markets. However, the existence of an anomalous equity premium raises important issues in the evaluation of public-sector investment projects. These issues are explored below. We begin by formalizing the argument that an equity premium may arise from uninsurable systematic risk in labour income, and show that, other things being equal, increases in public ownership of equity will improve welfare, up to the point where the equity premium is eliminated. Finally, we consider policy implications and the optimal extent of public ownership.

Climate change and biotic invasions: a case history of a tropical woody vine

The impacts of climate change in the potential distribution and relative abundance of a C3 shrubby vine, Cryptostegia grandiflora, were investigated using the CLIMEX modelling package. Based upon its current naturalised distribution, C. grandiflora appears to occupy only a small fraction of its potential distribution in Australia under current climatic conditions; mostly in apparently sub-optimal habitat. The potential distribution of C. grandiflora is sensitive towards changes in climate and atmospheric chemistry in the expected range of this century, particularly those that result in increased temperature and water use efficiency. Climate change is likely to increase the potential distribution and abundance of the plant, further increasing the area at risk of invasion, and threatening the viability of current control strategies markedly. By identifying areas at risk of invasion, and vulnerabilities of control strategies, this analysis demonstrates the utility of climate models for providing information suitable to help formulate large-scale, long-term strategic plans for controlling biotic invasions. The effects of climate change upon the potential distribution of C. grandiflora are sufficiently great that strategic control plans for biotic invasions should routinely include their consideration. Whilst the effect of climate change upon the efficacy of introduced biological control agents remain unknown, their possible effect in the potential distribution of C. grandiflora will likely depend not only upon their effects on the population dynamics of C. grandiflora, but also on the gradient of climatic suitability adjacent to each segment of the range boundary.

Synthesis of optically complex core-shell colloidal suspensions: Pathways to multiplexed biological screening

The ability to generate enormous random libraries of DNA probes via split-and-mix synthesis on solid supports is an important biotechnological application of colloids that has not been fully utilized to date. To discriminate between colloid-based DNA probes each colloidal particle must be 'encoded' so it is distinguishable from all other particles. To this end, we have used novel particle synthesis strategies to produce large numbers of optically encoded particle suitable for DNA library synthesis. Multifluorescent particles with unique and reproducible optical signatures (i.e., fluorescence and light-scattering attributes) suitable for high-throughput flow cytometry have been produced. In the spectroscopic study presented here, we investigated the optical characteristics of multi-fluorescent particles that were synthesized by coating silica 'core' particles with up to six different fluorescent dye shells alternated with non-fluorescent silica 'spacer' shells. It was observed that the diameter of the particles increased by up to 20% as a result of the addition of twelve concentric shells and that there was a significant reduction in fluorescence emission intensities from inner shells as an increasing number of shells were deposited.

Injury related risk behavior - a study of Australian skydivers

Risk taking behaviour has been identified as an important host-related determinant of injury in young adults. The aim of this study is to clarify the relationship between the two key elements of risk taking behaviour - ie, risk assessment and risk acceptance - in participants of a high risk sporting activity. Skydivers registered with the Australian Parachute Federation were sampled at several jump meetings held at three 'drop-zones' in North Eastern Australia. A cross sectional survey of 215 skydivers ascertained each subject's risk assessment of each of nine hypothetical sky diving scenes and whether or not they would jump in the described conditions. Variables which independently predicted an individual's risk assessment were age group (p < 0.05), gender (p < 0.05) and scene details (p < 0.001). Risk assessment was found to be a statistically significant predictor of the decision to jump, with a 22% decrease in the odds of jumping with every unit increase in risk assessment (OR = 0.78: 95% Cl; 0.76, 0.80). Gender was also found to be a statistically significant predictor of the decision to jump, with males being 19% more likely to jump than females, after controlling for age, experience, currency and risk assessment (OR = 1.19: 95% CI; 1.04, 1.38). The importance of these results is that, by quantifying the relationship between two key elements of risk taking behaviour and several important host factor determinants, they facilitate more informed discussion about the possible role of risk taking behaviour in the causation of injury.