Doctor of Philosophy

dissertationNewly discovered, noncoding RNA regulate cellular processes and gene expression. Simple model systems, such as quorum sensing systems, are studied to understand the mechanisms by which these RNA act on their targets. Quorum sensing is a process by which bacteria coordinate expression of their genes based on the local cell-population density. Up to five noncoding RNA, called small RNA (sRNA), in the quorum sensing systems of Vibrio harveyi and Vibrio cholerae regulate expression of the master transcriptional regulator, LuxR (V. harveyi ) and HapR (V. cholerae). LuxR/HapR regulate genes associated with virulence and bioluminescence that are downstream of the quorum sensing system. The V. harveyi and V. cholerae quorum sensing systems are topologically identical and their components are homologous, yet each responds differently under identical experimental conditions. Experiments show that all sRNA are necessary in V. harveyi and any single sRNA is sufficient in V. cholerae to repress bioluminescence. Hence, Qrr are additive in V. harveyi and redundant in V. cholerae. Subsequent experiments have shown that feedback in the sRNA circuit increases the expression of Qrr when one or more Qrr are removed. Differences in the tuning of this feedback are thought to cause the additive and redundant Qrr phenotypes; however, this long-standing hypothesis remains untested. In this work, a novel model of the V. harveyi and V. cholerae sRNA circuit is formulated and parameterized to identify parametric differences underlying the phenotypic differences. This yields a single model with two different parameterizations whose behavior agrees quantitatively with a variety of empirical data from V. harveyi and V. cholerae. The model, therefore, can be used for the in silico design, testing, and analysis of experiments and, as such, is a utility to generate experimentally verifiable hypotheses. Analysis of the model shows that the feedback in the sRNA circuit is neither necessary nor sufficient to explain the phenotypic differences, which is in contrast to the long-standing hypothesis. Rather, the additive and redundant Qrr phenotypes are emergent phenomena and, in the case of V. harveyi and V. cholerae, reflect differences in the saturation of the protein chaperon Hfq with sRNA. Overall, this suggests that Hfq is an important modulator of sRNA-facilitated repression of target mRNA

Measuring Controlled-NOT and two-qubit gate operation

Accurate characterisation of two-qubit gates will be critical for any realisation of quantum computation. We discuss a range of measurements aimed at characterising a two-qubit gate, specifically the CNOT gate. These measurements are architecture-independent, and range from simple truth table measurements, to single figure measures such as the fringe visibility, parity, fidelity, and entanglement witnesses, through to whole-state and whole-gate measures achieved respectively via quantum state and process tomography. In doing so, we examine critical differences between classical and quantum gate operation.Comment: 10 pages (two-column). 1 figur

Phonological Factors Affecting L1 Phonetic Realization of Proficient Polish Users of English

Acoustic phonetic studies examine the L1 of Polish speakers with professional level proficiency in English. The studies include two tasks, a production task carried out entirely in Polish and a phonetic code-switching task in which speakers insert target Polish words or phrases into an English carrier. Additionally, two phonetic parameters are studied: the oft-investigated VOT, as well as glottalization vs. sandhi linking of word-initial vowels. In monolingual Polish mode, L2 interference was observed for the VOT parameter, but not for sandhi linking. It is suggested that this discrepancy may be related to the differing phonological status of the two phonetic parameters. In the code-switching tasks, VOTs were on the whole more English-like than in monolingual mode, but this appeared to be a matter of individual performance. An increase in the rate of sandhi linking in the code-switches, except for the case of one speaker, appeared to be a function of accelerated production of L1 target items

It starts with the parents and ends with the parents

Alcohol is the most popular recreational drug in Australia. Despite the fact that many people gain enjoyment from alcohol related industries, alcohol is also implicated in much personal trauma and social damage. Parents play a key role in influencing alcohol use and driver behaviour in young people. The aim of this study was to gain an understanding of the attitudes and concerns of parents in Melbourne in relation to their teenage children\u27s use of alcohol and how they educate and/or provide role models for their adolescents with respect to alcohol usage. A convenience sample of parents with adolescent children participated in focus groups. Parents described patterns of alcohol use and perceived influences on consumption. They reported that they wanted to create safe environments for adolescents to consume alcohol but that they needed more support and information on which to base these decisions. There i, an opportunity for public health policy makers to specifically address parents and enhance their role in alcohol related road safety.<br /

Dynamic landscapes and human dispersal patterns : tectonics, coastlines, and the reconstruction of human habitats

Studies of the impact of physical environment on human evolution usually focus on climate as the main external forcing agent of evolutionary and cultural change. In this paper we focus on changes in the physical character of the landscape driven by geophysical processes as an equally potent factor. Most of the landscapes where finds of early human fossils and artefacts are concentrated are ones that have been subjected to high levels of geological instability, either because of especially active tectonic processes associated with faulting and volcanic activity or because of proximity to coastlines subject to dramatic changes of geographical position and physical character by changes of relative sea level. These processes can have both beneficial effects, creating ecologically attractive conditions for human settlement, and deleterious or disruptive ones, creating barriers to movement, disruption of ecological conditions, or hazards to survival. Both positive and negative factors can have powerful selective effects on human behaviour and patterns of settlement and dispersal. We consider both these aspects of the interaction, develop a framework for the reconstruction and comparison of landscapes and landscape change at a variety of scales, and illustrate this with selected examples drawn from Africa and Arabia

Liquor licences issued to Australian schools

BACKGROUND: Children's positive socialisation to alcohol is associated with early initiation of drinking and alcohol-related harm in adult life. Internationally, there have been reports of adults' alcohol consumption at school events in the presence of children. The aim of this research was to identify the conditions under which Australian schools are required to apply for a liquor licence and the associated prevalence of liquor licences for these events where children were likely to be present. METHODS: A document review was conducted to examine temporary liquor licensing legislation. Quantitative analysis was used to examine relevant licensing data. Coding criteria was developed to determine school type, student year levels and the likely presence of children. RESULTS: Four jurisdictions provided data on 1817 relevant licences. The average annual licences/100 schools was highest amongst Independent schools followed by Catholic and public (government) schools. The rates were highest in Queensland and Victoria where children were present at 61% and 32% of events respectively. CONCLUSIONS: While there are legislative differences across jurisdictions, the prevalence of adults' alcohol use at school events in the presence of children may reflect the various education department policies and principals' and school communities' beliefs and attitudes. Licences are not required for all events where liquor is consumed so the prevalence of adults' use of alcohol at school events is likely to be higher than our analyses imply. Such practices may undermine teaching about alcohol use in the school curriculum and health promotion efforts to develop alcohol-free events when children are present

Principals' reports of adults' alcohol use in Australian secondary schools

Background - Schools provide opportunities for parents and the wider community to connect and support the physical and emotional wellbeing of their children. Schools therefore have the potential to play a role in the socialisation of alcohol use through school policies and practices regarding consumption of alcohol by adults at school events in the presence of children. Methods - This survey was undertaken to a) compare the extent to which alcohol is used at secondary school events, when children are present, in the states of New South Wales (NSW) and Victoria (VIC), Australia; b) describe principals’ level of agreement with these practices; c) their awareness of state policies on this issue; and d) the predictors of such events. A random sample of secondary schools, stratified to represent metropolitan and non-metropolitan schools were invited to participate. Bivariate and multivariate analysis were conducted with p values < 0.05 considered significant. Results - A total of 241 (43 %) schools consented to participate in the study. Fifteen percent of participating NSW schools and 57 % of VIC schools held at least one event in which alcohol was consumed by adults in the presence of children in the year before the survey. Of the 100 reported events, 78 % were Year 12 graduation dinners, and 18 % were debutante balls. Compared to NSW principals, VIC principals were significantly more likely to agree with the use of alcohol at these events; significantly less likely to be aware of their state education department policy on this issue; have a policy at their own school or support policy that prohibits alcohol use at such events; and less likely to report having enough Information to make decisions about this. Conclusions - There is a growing focus on adults’ use of alcohol at school events when children are present. Schools can play an important role in educating and socialising children about alcohol via both the curriculum and policies regarding adults’ alcohol use at school events. Findings from this study suggest education department and school-based policies that prohibit or restrict the use of alcohol, are significant predictors of adults’ alcohol use at school events when children are present

Geographic variation in the carotenoid plumage pigmentation of male house finches ( Carpodacus mexicanus )

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72538/1/j.1095-8312.1993.tb00685.x.pd

Predicting the Effect of Surface Texture on the Qualitative Form of Prehension

Reach-to-grasp movements change quantitatively in a lawful (i.e. predictable) manner with changes in object properties. We explored whether altering object texture would produce qualitative changes in the form of the precontact movement patterns. Twelve participants reached to lift objects from a tabletop. Nine objects were produced, each with one of three grip surface textures (high-friction, medium-friction and low-friction) and one of three widths (50 mm, 70 mm and 90 mm). Each object was placed at three distances (100 mm, 300 mm and 500 mm), representing a total of 27 trial conditions. We observed two distinct movement patterns across all trials—participants either: (i) brought their arm to a stop, secured the object and lifted it from the tabletop; or (ii) grasped the object ‘on-the-fly’, so it was secured in the hand while the arm was moving. A majority of grasps were on-the-fly when the texture was high-friction and none when the object was low-friction, with medium-friction producing an intermediate proportion. Previous research has shown that the probability of on-the-fly behaviour is a function of grasp surface accuracy constraints. A finger friction rig was used to calculate the coefficients of friction for the objects and these calculations showed that the area available for a stable grasp (the ‘functional grasp surface size’) increased with surface friction coefficient. Thus, knowledge of functional grasp surface size is required to predict the probability of observing a given qualitative form of grasping in human prehensile behaviour