International Factors Influencing Australian Governments\u27 Responses to the Indochinese Refugee Problem

On the effects of Australia\u27s Indochinese refugee policies following the Vietnam War

“Step by step”: high frequency short-distance epizoochorous dispersal of aquatic macrophytes

Aquatic macrophytes can successfully colonise and re-colonise areas separated by space and time. The mechanisms underlying such “mobility” are not well understood, but it has often been hypothesised that epizoochory (external dispersal) plays an important role. Yet, there is only limited, and mostly anecdotal, evidence concerning successful epizoochorous dispersal of aquatic macrophytes, particularly in the case of short-distance dispersal. Here we examine in situ and ex situ dispersal of aquatic macrophytes, including three invasive alien species. A high frequency of Lemna minor Linnaeus dispersal was observed in situ, and this was linked to bird-mediated epizoochory. We concluded that wind had no effect on dispersal. Similarly, in an ex situ examination Lemna minuta Kunth and Azolla filiculoides Lamarck, were found to be dispersed with a high frequency by mallard ducks (Anas platyrhynchos). No dispersal was measured for Elodea nuttalli (Planchon) H. St. John. It is concluded that short-distance or “stepping-stone” dispersal via bird-mediated epizoochory can occur with high frequencies, and therefore can play an important role in facilitating colonisation, range expansion and biological invasion of macrophytes

How Experts Learn: The Role of Deliberate Practice

The aim of this thesis was to examine how experts learn using the theory of deliberate practice. Expert and intermediate Gaelic football players practiced kicking, with their learning being assessed between a pre-test and retention test. A novel method to measure the tenets of deliberate practice during the activity, as opposed to retrospectively, was used throughout the thesis. Findings support previous research on the mechanisms and strategies engaged in by experts as they aim to improve performance and how they differ to lesser-skilled individuals. In line with the theory of deliberate practice, in Chapter 2 and 3 the experts rated practice higher for effort and lower for enjoyment, as well as practicing a more relevant skill in Chapter 2, when compared to intermediates. Moreover, they improved kicking accuracy between pre-test and retention test, whereas the intermediate group did not. In addition, the thesis identified differences between the cognitive mechanisms of experts and intermediates that underpin their respective performance. Expert groups engaged in greater cognitive processing during (Chapter 2 and 3) and between (Chapter 3) practice sessions when compared to intermediates. Chapter 4 examined the impact of applying these expert cognitive processes to the deliberate practice and performance of a youth intermediate group. A training group practiced kicking with an intervention designed to increase cognitive processing, whereas a control group practiced kicking without intervention. Findings support previous research by providing evidence of the outcome of such an intervention on deliberate practice. The training group demonstrated greater cognitive effort and less enjoyment during practice and greater improvements in accuracy after practice compared to the control group. Overall, findings in this thesis support the theory of deliberate practice and extend the research on the role of cognitive processing in effective skill acquisition

A Model of Direct Gauge Mediation

We present a simple model of gauge mediation (GM) which does not have a messenger sector or gauge singlet fields. The standard model gauge groups couple directly to the sector which breaks supersymmetry dynamically. This is the first phenomenologically viable example of this type in the literature. Despite the direct coupling, the model can preserve perturbative gauge unification. This is achieved by the inverted hierarchy mechanism which generates a large scalar expectation value compared to the size of supersymmetry breaking. There is no dangerous negative contribution to the squark, slepton masses due to two-loop renormalization group equation. The potentially non-universal supergravity contribution to the scalar masses can be suppressed enough to maintain the virtue of the gauge mediation. The model is completely chiral, and one does not need to forbid mass terms for the messenger fields by hand. Beyond the simplicity of the model, it possesses cosmologically desirable features compared to the original models of GM: an improved gravitino and string moduli cosmology. The Polonyi problem is back unlike in the original GM models, but is still much less serious than in hidden sector models.Comment: LaTeX, 12 page

Menopause, cognition and dementia – A review

There is increasing evidence that menopausal changes can have an impact on women’s cognition and potentially, the future development of dementia. In particular, the role of reduced levels of estrogen in postmenopausal changes has been linked to an increased risk of developing dementia in observational studies. Not surprisingly, this has led to several clinical trials investigating whether postmenopausal hormone replacement therapy can potentially delay/avoid cognitive changes and subsequently, the onset of dementia. However, the evidence of these trials has been mixed, with some showing positive effects while others show no or even negative effects. In the current review, we investigate this controversy further by reviewing the existing studies and trials in cognition and dementia. Based on the current evidence, we conclude that previous approaches may have used a mixture of women with different genetic risk factors for dementia which might explain these contradicting findings. Therefore, it is recommended that future interventional studies take a more personalised approach towards hormone replacement therapy use in postmenopausal women, by taking into account the women’s genetic status for dementia risk