List of Records in UQ Theses Collection (MPhil and PhD) - UQ eSpace

Accidental Authors – Students experiment with making writing explicit during their Research Higher Degree

Naomi Anastasi — 2009-09-03T15:02:35Z

The implicit position of writing during Research Higher Degree (RHD) candidature shapes how students in science approach the task of writing their theses. The dedication of universities to the principles of research has pushed writing to the fringes of the research higher degree. When writing is pushed to the fringes, it is rarely taught explicitly as an integral part of the postgraduate program. This research has found that students who are concerned with writing a thesis often require writing to be discussed explicitly during their education. In response to the absence of explicit instruction on writing, students turn to the principles of research to discover how to write their theses. However, students find that writing belongs to a different epistemological tradition than scientific research. This investigation found that as students realise that research is different from writing, they often write their theses by mimicking the work of other published authors in the same field. These findings emerge from eight semi–structured interviews with linguistically homologous students from a science faculty at a research-intensive university in Australia. These interviews show that students are initiating their own writing groups to learn more about writing. This research presents a case study which culminates in recommendations about how to re-position writing as an explicit discourse requiring attention during the research higher degree. These writing recommendations are developed in this research by analysing the principles of writing programs, examining the literature on writing groups, and reflecting the experience of students during the research higher degree.

Accounting for ecosystem dynamics and uncertainty in conservation planning

Hedley Grantham — 2009-07-13T13:41:56Z

A systematic approach to planning, decision-making and management has become best-practice in conservation over the past two of decades. The field of ‘systematic conservation planning’ is concerned with identifying cost-effective places and actions to protect biological diversity. Past research has focused on static assessments. However, given the fact that biological diversity and processes that threaten its persistence vary in space and time, conservation assessments might need to be made in a dynamic context. In addition, we must explicitly account for the trade-offs associated with implementing conservation actions and investing in improved knowledge and learning to reduce uncertainty on where, how and when to act. The aim of this thesis was to develop novel approaches for accounting for both ecosystem dynamics and uncertainty in conservation planning. Ecosystems are generally treated as static in conservation planning despite many being spatially and temporally dynamic. For example, pelagic marine ecosystems are quite dynamic because ecological processes, such as eddies, that produce resources that many species depend on can be erratic. In chapter two we explored the issue of developing a system of fixed protected areas that consider the physical and biological dynamics typical of the pelagic realm. The approach was to maximize the representation of key fisheries species and species of conservation concern due to significant declines in their abundance, within a network of protected areas. We also ensured that protected area design reflected system dynamics and this was achieved by representing key oceanographic process (such as upwellings and eddies), and biological processes (such as the abundance of small pelagic fish) in protected areas. To account for the variability where these processes occur, we used time series data to find both predictable areas and anomalies, assuming that their past location was somewhat reflective of their future locations. Implementing conservation actions that are fixed in space and time are probably not the most effective strategy in ecosystems that are dynamic. This is because of the movements of particular species. For example, many species have distributions and abundances that change seasonally and might only require temporary management in particular areas. In chapter three, we tested the utility of three approaches to implementing fisheries closures to reduce bycatch in the South African Longline Fishery; 1) time closures, 2) permanent spatial closures and 3) episodic spatial closures. In chapter three, we identified these closures using an existing database containing catch and bycatch data from 1998 to 2005. There was variation where and when different species were caught as bycatch, and it was determined seasonal area closures were the best strategy. This was because it achieved the same conservation objectives for bycatch species as the other types of closures, but impacted less on the long-lining industry. While this result is intuitive, it demonstrated quantitatively, how much more effective moveable management can be. Decisions on where conservation actions are implemented are always based on incomplete knowledge about biological diversity. It is generally assumed that gathering more data is a good investment for conservation planning. However, data can take time and incur costs to collect and given habitat loss, there are both costs and benefits associated with different levels of investments in knowledge versus conservation implementation. In chapter four, the aim was to determine the return on investment from spending different amounts on survey data before undertaking a program of implementing new protected areas. We found that, after an investment of only US$100,000, there was little increase in the effectiveness of conservation actions, despite the full species dataset costing at least 25 times that amount. Surveying can take time because of expertise limitations, logistics and funding shortfalls. Biological diversity may be lost while data collection occurs conversely, not collecting enough data can lead to erroneous decisions. Additionally, resources spent on learning may be better spent on other actions. In chapter five, in a series of retrospective simulations, we compared the impact of spending different amounts of time collecting biological data prior to the implementation of new protected areas. The aim was to find the optimal survey period given the trade-off between gaining knowledge to improve conservation decisions while there is concurrent loss of habitat. We discovered that surveying beyond two years rarely increased the effectiveness of conservation decisions, despite a substantial increase in the knowledge of species distributions. Often there are choices between different actions and uncertainty as to which are the most effective. In chapter six, we discuss how the principles of adaptive management might be applied to conservation planning. Improving future management decisions through learning should be viewed as essential in all conservation plans but such learning is often included as a minor step, or is completely ignored. In this chapter we provide a brief overview of an adaptive framework for conservation planning and ideas for future research.

Accurate Location Service for 3G Cellular Networks

Kumar-Mills, Dinesh — 2008-06-13T09:08:19Z

ACQUISITION OF WORD ORDER IN CHINESE AS A FOREIGN LANGUAGE: AN ERROR TAXONOMY

Jiang, Wenying Wendy — 2008-11-21T14:33:55Z

Research in the field of Chinese second/foreign language (L2) acquisition, at present, does not match the increasing demand to learn Chinese as an L2, given that Chinese is the fastest growing foreign language (FL) in countries such as Japan, South Korea, the United States, Canada and Australia. There is a significant gap between Chinese L2 acquisition research and the large body of literature in second language acquisition (SLA), which mainly focuses on English L2. The need for more research in Chinese SLA is compelling. Particularly, research in Chinese L2 word order acquisition requires more attention because word order plays a more complex role in Chinese than in English. Chinese relies heavily on word order for information structuring of a sentence because this language lacks other means, such as verb endings indicating tense and aspect, to accomplish this function. Due to the different roles word order plays in Chinese and English, adult English-speaking learners find Chinese word order acquisition very challenging. Chinese L2 word order errors frequently occur in learners L2 production. However, Chinese L2 researchers and teachers are left with no means to adequately describe and explain these errors for instruction purposes. This dissertation develops such a means a comprehensive taxonomy of Chinese L2 word order errors. This taxonomy organizes these errors into a logical system of classification. Through the classification, explicit description of various Chinese L2 word order errors is achieved, and specific sources of these errors are traced. Data was collected from 116 native-English-speaking learners of Chinese at a large university in Australia. The Chinese L2 learners were divided into three proficiency levels based on their institutional status. Four hundred and eight word order errors were extracted by qualitatively analyzing the learners written samples. Among the 408 word order errors, 404 (99%) are successfully classified into different categories according to a new criterion proposed in this dissertation. The new taxonomy provides a principle-based description and explanation of various Chinese L2 word order errors. A word order error is deemed to constitute an error when it violates a relevant word order principle (or sub-principle). These principles not only explain why an error is an error but also provide a means for correcting the error. In a pedagogical sense, the directness and explicitness in explaining word order errors achieved by employing this taxonomy cannot be achieved by relying on any other sources of errors available in the literature. The new taxonomy overcomes the limitations of existing taxonomies in the literature that are either superficial, or unsystematic, or not empirically testable. For example, it draws on the Cognitive Functionalist Approach of L2 acquisition. Both its description and explanation of Chinese L2 word errors go beyond superficiality. The approach maintains that adult L2 learners conceptualization of the world is initially based on their L1. Their conceptualization of the world imposes constraints on the linguistic structures of their L2. Therefore, errors may occur when English learners of Chinese impose their conceptualization based on the English language onto the Chinese structures. The new taxonomy is systematic because it categorizes word order errors using one criterion. New categories emerging from the data and the existing categories from the literature are incorporated into one system. Finally, the new taxonomy is empirically testable because many new categories emerged from the data. It is an open-ended rather than a closed system. New categories can be added as necessary. The dissertation finds that violation of relevant word order principles has a high explanatory value for the various word order errors encountered in the data. This has clear pedagogical implications. Chinese L2 learners generally lack awareness of the word order principles (and sub-principles) on which the new taxonomy is based. These principles and sub-principles are seen to be of considerable importance to the acquisition of Chinese L2 word order. In order to improve learners word order performance, the results of this study indicate that it is imperative for the basic Chinese word order principles be included in a CFL curriculum.

Actions speak louder than words : accelerating national policies for obesity and related chronic illness

Gross, Paul — 2008-11-21T15:29:43Z

In 2006, over 60% of adult Australians are obese or overweight as measured by Body Mass Index (weight in kilograms divided by height in metres squared). Adult and childhood obesity is growing at about one percentage point per year. A central tenet of this thesis is that with such prevalence and growth rates of the human girth, obesity is a major public policy issue that has a large direct cost in the burden of related chronic conditions and an even larger hidden cost of lost productivity that is not being addressed by governments in Australia. With yet another report on obesity imminent from the National Obesity Task Force, I argue that Australia needs to replace its reliance on talk-fests about obesity by government policies that redefine obesity as a national health priority area requiring immediate collective action by households, the food, drink and advertising industries, health insurers and the federal and state governments. The obesity epidemic requires embedding into Medicare and private health insurance the types of economic incentives that are now reducing the risks of unhealthy lifestyles in other parts of the world, emphasizing the role of personal responsibility in changing unhealthy lifestyles. While all these initiatives are, given the current chasm between federal and statelterritory governments, rather difficult to implement, I argue that policies are required to prevent obesity in all age groups, and complacency is not an option. This thesis makes six substantive contributions to the policy debate on obesity in Australia. First, it identifies the types of direct treatment costs and the hidden costs of workloss (absenteeism) and lost productivity while at work (presenteeism) that are generated by highly prevalent chronic disorders that are poorly managed in Australia. Second, it provides new estimates of the costs of obesity, overweight and physical inactivity in 2004105, identifying both the direct and indirect costs of chronic conditions associated with these three risk factors. Third, it analyses data from a small pilot study of weightloss in Australia using a new behavioural model, concluding that policies that buttress self-efficacy and intrinsic motivations should be considered in government policy for obesity. Fourth, drawing on the new discipline of behavioural economics, it concludes that regulation of advertising of food and drinks to children is unlikely to be as effective as economic incentives that enhance the sense of personal responsibility. Fifth, it proposes changes in the economic incentives within the Medicare and private health insurance systems, and it identifies gaps in workplace health promotion that should be remedied by gradual changes in workers' compensation insurance and new tax incentives to employers. Sixth, it recommends the creation of a new National Council on Obesity and Chronic Disease headed by a Parliamentary Secretary responsible to the Cabinet for the development of cross-portfolio strategies and the creation of public-private partnerships against obesity and chronic conditions. The last recommendation emerges as a preferred alternative to leaving all major decisions on obesity and related chronic conditions in the hands of politically-charged bodies such as the Council of Australian Governments (COAG). The thesis concludes with a set of recommendations on macro-environments that need to be considered in devising new policies to attack the obesity epidemic on both the demand side (i.e., the population) and the supply side (i.e., all providers of care, all payers for such care and all suppliers of dietary intakes who can influence weightloss behaviour), all influenced by new economic and behavioural incentives for healthier diets and physical activity rather than by government regulatory zeal.

Active Audition for Robots using Parameter-Less Self-Organising Maps

Berglund, Erik Johan — 2008-11-21T15:03:07Z

How can a robot become aware of its surroundings? How does it create its own subjective, inner representation of the real world, so that relationships in the one are reflected in the other? It is well known that structures analogous to Self-Organising Maps (SOM) are involved with this task in animals, and this thesis undertakes to explore if and how a similar approach can be success- fully applied in robotics. In order to study the environment-to-abstraction mapping with a minimum of guidance from directed learning and built-in design assumptions, this thesis examines the active audition task in which a system must determine the direction of a sound source and orient towards it, both in horizontal and vertical direction. Previous explanations of directional hearing in animals, and the implementation of directional hearing algorithms in robots have tended to focus on the two best known directional clues; the intensity and time differences. This thesis hypothesises that it is advantageous to use a synergy of a wider range of metrics, namely the phase and relative intensity difference. A solution to the active audition problem is proposed based on the Parameter- Less Self-Organising Map (PLSOM), a new algorithm also introduced in this thesis. The PLSOM is used to extract patterns from a high-dimensional input space to a low-dimensional output space. In this application the output space is mapped to the correct motor command for turning towards the source and focusing attention on the selected source by filtering unwanted noise. The dimension-reducing capability of the PLSOM enables the use of more than just two directional clues for computation of the direction. This thesis presents the new PLSOM algorithm for SOM training and quantifies its performance relative to the ordinary SOM algorithm. The mathematical correctness of the PLSOM is demonstrated and the properties and some applications of this new algorithm are examined, notably in automatically modelling a robot's surroundings in a functional form: Inverse Kinematics (IK). The IK problem is related in principle to the active audition problem - functional rather than abstract representation of reality - but raises some new questions of how to use this internal representation in planning and execution of movements. The PLSOM is also applied to classification of high-dimensional data and model-free chaotic time series prediction. A variant of Reinforcement Learning based on Q-Learning is devised and tested. This variant solves some problems related to stochastic reward functions. A mathematical proof of correct state-action pairing is devised.

Acumen, Ambivalence and Ambiguity: Stories of women with asthma

Rose, Gabrielle Maree — 2008-11-21T16:45:22Z

Australia has one of the highest prevalence rates of asthma in the world and is one of the leading countries in the public health approach to the problem. Yet despite advances biomedical and public health discourses still provide various definitions of asthma and, at times, contradictory models of aetiology, treatment and prevention. These contrasting views are disseminated to the public by the media and in clinical encounters: they inform medical practice, pharmaceutical policy, and public perceptions and responses to the illness. In this thesis I explore the convergences and discrepancies in the representation of asthma and contrast these with the lived experiences of women with asthma. The thesis draws on research undertaken in Queensland, Australia, with women with asthma, and with their physicians and other people working in the field of asthma policy, practice and research. It is a medical anthropological approach to the problem of asthma and uses qualitative and quantitative methods in the collection of data. It then triangulates the qualitative and quantitative findings. The quantitative data are presented first and these are juxtaposed with the qualitative findings. The major concepts to emerge from the qualitative data include the acumen women have in terms of knowledge of their asthma; ambivalence in managing their asthma; and ambiguity in terms of the quality of their life. The findings of the research demonstrate that women with asthma, and the institutions in place to deal with it, suffocate, metaphorically keeping bodies just below the surface, suppressing their life in lieu of their illness. The central argument in this thesis is that despite positive advances in the area of asthma research, policy and practice, the continuing reliance on medical and public health models for the creation of knowledge in the area of chronic illness fails to adequately respond to the needs of women with asthma. The fundamental outcome of the research shows that the social and cultural capital a woman with asthma has in relation to knowledge, attitudes and practices, translates into disposition towards the management of her chronic condition. This is sometimes in direct contrast with existing knowledges. I argue that instead of research and practice that focuses on the deficits in knowledge of people with asthma, an asset-based approach to the problem of asthma one that focuses on existing knowledge, attitudes and practices of these women may assist in managing the chronic illness condition in a more effective fashion.

Acupuncture Management of Frozen Shoulder

Lee, David Robert Kittak — 2008-11-21T15:23:02Z

Background: Frozen shoulder or idiopathic adhesive capsulitis is an enigma of musculo-skeletal medicine. It is a difficult condition to treat and its etiology is still unknown. Aim: The aim of this study is to investigate whether acupuncture has a role in the management of frozen shoulder. Objectives: An in-depth literature review was conducted on all aspects related to the current concepts and treatments for frozen shoulder. Although there were discussions on associated conditions and possible causes of frozen shoulder, there is currently no consensus on its management. Acupuncture has been used successfully as a treatment for frozen shoulder by many eastern practitioners. Unfortunately, their claims could not be substantiated due to a lack of properly conducted clinical trials. An acupuncture treatment protocol for the management of frozen shoulder was designed based on both Traditional Chinese Medicine (TCM) and Anatomical principles. This protocol was then tested with a clinical trial. Methods: A pilot study, using a prospective case series of 20 patients suffering with the adhesive phase of frozen shoulder, was conducted to test the effectiveness of the acupuncture treatment protocol. This study included specific selection and exclusion criteria; an objective assessment of the range of movement and subjective assessments on the quality of life and pain. All data were collated and analysed with SPSS version 12. The pretreatment and post-treatment data were tested using both parametric paired sample t test and non-parametric Wilcoxon signed-rank test. Results: The patients profile confirmed the affected age group and gender distribution to be similar to those in the literature search. Unfortunately, due to the small sample size, there were no significant associated conditions demonstrated. There were twice as many cases of primary frozen shoulder than secondary frozen shoulder in this study. These analyses suggested that there were significant changes in all three areas of assessment range of shoulder movement, quality of life and visual analogue pain scale (p<0.001). At completion of treatment, the result revealed that the acupuncture treatment protocol was successful in 60%, and moderately successful in 15%, of the 20 cases tested. This outcome was compared with the study by Omari and Bunker which showed only 12% success with conservative western medical treatments, suggesting that acupuncture may be better than conservative western medical treatments. Conclusion: Acupuncture treatment is less costly and has minimal side effects. It should be part of the non-procedural modalities offered to patients suffering with frozen shoulder. For patients who have failed western conservative managements, a trial of acupuncture treatment should be considered prior to embarking on the more invasive interventions..

Adaptation by prediction: Reading the play in robot soccer

David Michael Ball — 2008-08-20T11:50:21Z

Adaptive Phase Measurements

Berry, Dominic William — 2008-11-21T21:39:35Z

In this thesis I consider the general problem of how to make the best possible phase measurements using feedback. Both the optimum input state and optimum feedback are considered for both single-mode dyne measurements and two-mode interferometric measurements. I derive the optimum input states under general dyne measurements when the mean photon number is fixed, both for general states and squeezed states. I propose a new feedback scheme that introduces far less phase uncertainty than mark II feedback, and is very close to the theoretical limit. I also derive results for the phase variance when there is a time delay in the feedback loop, showing that there is a lower limit to the introduced phase variance, and this is approached quite accurately under some conditions. I derive the optimum input states for interferometry, showing that the phase uncertainty scales as 1/N for all the common measures of uncertainty. This is contrasted with the |j0> state, which does not scale as 1/N for all measures of phase uncertainty. I introduce an adaptive feedback scheme that is very close to optimum, and can give scaling very close to 1/N for the uncertainty. Lastly I consider the case of continuous measurements, for both the dyne and interferometric cases.

Addiction Neuroethics: The Promises and Perils of Neuroscience Research on Addiction

Adrian Carter — 2009-08-05T16:02:43Z

Drug addiction is a significant problem facing most societies. It is associated with increased violence, crime and mental illness, and is one of the leading causes of preventable mortality and disability in most developed societies, accounting for over 12% of the total burden of disease (Begg et al., 2007). Neuroscience promises to significantly reduce the incidence and severity of addictive drug use, and the harm that it causes, by providing more effective and better targeted treatment of addiction (Volkow and Li, 2005). Proponents argue that an increased understanding of the neurobiological basis of drug addiction will also lend support for more humane social policies. These policies will recognise that addiction is a neuropsychiatric condition that should be treated therapeutically, leading to increased investment in addiction research and treatment (Dackis and O'Brien, 2005; McLellan et al., 2000). Optimism about the benefits of an understanding of the neurobiological basis of addiction needs to be tempered by more critical considerations. Overly simplistic interpretations of what this kind of approach reveals about addiction could result in less welcome consequences, especially if inappropriate use is made of emerging neurotechnologies, such as coerced use of naltrexone implants, population-wide vaccination programs against addiction, or the promotion of heroic ‘cures’ for addiction, such as neurosurgery and deep brain stimulation. This thesis examines both the potentially welcome and unwelcome uses of neurobiological research of addiction with the aims of maximising the benefits, while minimizing any unanticipated harms. I refer to this as Addiction Neuroethics. The primary aims are to examine: (1) the impact that neuroscience research may have upon our understanding of autonomy and self-control in addicted individuals, (2) the implications this understanding may have for how we treat individuals with an addiction; and (3) the conditions under which it would be ethically acceptable to use various technologies emerging from this research. This thesis falls into three parts. First, a concise and accessible summary of the key findings of recent genetic and neuroscience research of addiction is provided. This includes the neuroanatomy of addiction (e.g. the mesolimbic reward pathway), the molecular and cellular biology of addiction, neurocognitive changes, and the role of genetic and environmental vulnerabilities. The second part of this thesis explores how neuroscience research may influence the way that modern societies think about drug use and addiction, and deal with those that suffer from it. This section addresses the central question: do addicted persons have the capacity to make autonomous decisions regarding their own drug use? This raises a number of additional questions. How much responsibility and blame should we attribute to addicted individual’s for their actions? How should society deal with addicted persons, or respond to the harm that they cause? Should society coerce addicted individuals into treatment, and if so, under what conditions? The third part of this thesis examines the ethical issues raised by the use of powerful new technologies that are emerging from neurobiological research on addiction, such as novel psychopharmacologies, depot implants, drug vaccines, neurosurgery and brain stimulation, neuroimaging and genetic testing. The report also considers the more speculative possibility that addiction neurobiology may improve our ability to prevent the development of addiction, for example, by using genetic screening to identify individuals at high risk of addiction and ‘drug vaccines’ to prevent these individuals from becoming addicted. This thesis demonstrates that the chronic use of addictive drugs has significant impacts upon key decision-making regions of the brain (e.g. motivation, memory, impulse inhibition) that affect addicted individuals ability to choose not to use drugs. While the autonomy of addicted individuals is impaired in certain situations, and to varying degrees, it is not extinguished. Rather than deny autonomy, we should aim to engage addicted individuals in ways that increase their autonomy. For example, coerced treatment of addiction may be a valid approach to getting addicted individuals in treatment. However we should avoid overriding the autonomy of addicted individuals by offering treatment as an alternative to punishment for some crimes (e.g. theft to fund drug habit). Such treatment should aim to treat a medical condition, and not be a form of extrajudicial punishment. Addiction is a highly stigmatised condition. This can significantly impact upon the way in which neuroscience research is understood and applied. Scientists, clinicians and policy makers must be mindful of over-enthusiastic applications of novel technologies that may be prematurely embraced and promoted to a desperate and vulnerable population without proper evaluation of the risks, or without considering how these technologies may be used once approved. The treatment of addiction should be judged by its efficacy and safety, as for any other medical treatment. Addicted individuals should be treated as any other individual suffering from a medical condition. The thesis concludes with some general suggestions about the directions in which this debate is likely to develop and identifies areas that will require further analysis and empirical investigation.

Adolescent pathways to mental health services

Wagner, Ingrid — 2008-11-21T21:02:04Z

The age period of adolescence is significant for epidemiologic research because of the emergence of emotional and behavioral problems, which occur during this time. Many studies have shown that few of the adolescents identified as suffering significant psychological disturbance receive help from specialist mental health agencies. The recognition of this gap between identified need in the community and the utilisation of services underlies the pathways model proposed by Goldberg and Huxley (1980). Understanding the pathways by which the distressed person reaches specialist services may assist in the improvement of the quality of mental health care in the community. The studies of pathways have mainly focused on adult populations. However the dominant patterns of General Practitioner and Medical pathways found in these studies are inconsistent with those of adolescents. Their different level of social and emotional development affects both how they seek help and how their problems are perceived by significant others. This study examined the records of initial contact for adolescents aged 12 to 18 years, who were referred to three community based mental health clinics serving a regional health district of Brisbane, during the period of 1 June 1997 to 30 June, 1998. The results showed that the pathways by which adolescents reach mental health services were broader in scope than those of adults. Parent, Education Professionals and General Practitioners were the dominant pathways to service. The factors most commonly presented to mental health services at the initiation of help seeking were familial/life event problems and behavioral problems. A notable feature in the presentations was the alarming and disturbing quality of a substantial proportion of the identified problems. It is considered that the social impact of the problems is a strong precipitant in referral. The significant findings of the study are that the pathways vary by the age and sex of the adolescent, and that some presentation problems are more highly associated with particular pathways.

Adopting the principles of ‘Crew Resource Management’ to the offshore drilling industry

Ahern, Dan — 2009-10-15T09:57:40Z

This report recommends a strategy for the introduction of aviation style Crew Resource Management (CRM) to the offshore drilling industry. The purpose of this study was to investigate ways CRM could be applied to the offshore drilling industry as a means of mitigating the risks of human error, and in particular risks to health and safety. Research has been conducted in accordance with accepted social science research methodologies. Key processes involved a formal literature review plus the formation of a Nominal Reference Group and application of the Delphi Technique as the primary data gathering method. Case studies have been used throughout this report to provide examples of key points and to illustrate the need for effective management of human error in both the aviation and drilling industries. Results from this study provided the basis for the development of a preferred implementation plan as a practical means for adopting the principles of CRM to the offshore drilling industry. Recommendations for furthering this work include the need to benchmark training as a means of providing better evidence that CRM leads to improved safety and operational performance, the need to develop a business plan to justify the cost and effort, the need to further involve key stakeholders in the process, and they need to solicit endorsement for this project from influential industry bodies.

ADSORPTION OF FLUIDS IN FINITE SIZED CARBON PORES WITH FUNCTIONAL GROUPS

Wongkoblap, Atichat — 2008-06-27T09:24:54Z

Adult Oral Health Programme: The Effect of Periodontal Treatment and the Use of a Triclosan Containing Toothpaste on Glycaemic Control in Diabetics

Ohnmar Tut — 2009-10-31T07:22:37Z

Adult Oral Health Programme: The Effect of Periodontal Treatment and the Use of a Triclosan Containing Toothpaste on Glycaemic Control in Diabetics Abstract Aim: The aim of the research study is to establish an adult oral health programme for diabetics in Majuro, Republic of the Marshall Islands in order to determine the impact of non-surgical periodontal treatment followed by the use of a triclosan containing dentifrice on the maintenance of periodontal health and glycaemic control in type 2 diabetic patients. Hypothesis: Non-surgical periodontal treatment results in improved periodontal health and better glycaemic control in diabetics and use of a triclosan containing toothpaste is effective in maintaining this improvement in diabetics. Methods: An adult oral health programme was created, within which was conducted a two-group randomised clinical trial to address the hypothesis that non-surgical periodontal treatment results in improved periodontal health and better glycaemic control in type 2 diabetics and that the use of a triclosan containing toothpaste is effective in maintaining this improvement in diabetics. In this double blind controlled trial, sixty adult patients (aged 35 to 65 years) with type 2 diabetes mellitus having a minimum of 16 teeth received non-surgical periodontal treatment. Half of the patients were randomly assigned to use a triclosan containing toothpaste, Colgate Total, and the other group a non-triclosan toothpaste, Colgate Fluoriguard. The study evaluated the improvement in periodontal health by recording Probing Pocket Depth (PPD) on 6 sites of each tooth, and the number of sites bleeding on probing (BOP) at baseline, and at 6 months and 12 months after treatment. The second part of the study evaluated the impact of improvement of periodontal health on glycaemic control in type 2 diabetics by measuring HbA1c and RBS, and also assessing the levels of C-Peptides and CRP at baseline, and at 6 months and 12 months after treatment. The study also evaluated the effectiveness of a triclosan containing toothpaste in maintaining the improvement in periodontal health after non-surgical periodontal treatment. Results: The results showed that it was feasible to establish an oral health programme for the diabetics and could improve their periodontal health, and that toothpaste containing triclosan is effective in maintaining the improved periodontal heath in type 2 diabetics. Mean PPD dropped from 2.35mm to 1.95mm in the triclosan group and from 2.49mm to 2.24 mm in the non-triclosan group and the mean number of BOP sites dropped from 4.9 to 2.8 in the triclosan group and from 4.7 to 3.2 in the fluoriguard at 12 month visits. However, the results did not show improvement of HbA1c nor RBS levels in either group. C-Peptide levels increased and C-Reactive Protein levels decreased in both groups, however, not to significant levels at 12 month visits. Conclusion: The results of this research study lead to the conclusion that treating periodontal infection has effect of periodontal health of type 2 diabetic patients and following-up with simple personal oral hygiene of regular tooth-brushing helps maintain their periodontal health. This programme also proved that this type of oral health programme is feasible and valuable for diabetics in isolated places like the Marshall Islands, where infrastructure, personnel and resources are limited to treat microvascular and macrovascular complications of diabetes. As for the effectiveness of treating periodontal infections on glycaemic control of diabetics, this study failed to support the hypothesis that non-surgical treatment plus triclosan containing toothpaste would lead to better glycaemic management through improved periodontal health.

Adults Before Their Time: Parentification During Adolescence In Divorcing And Married Families

Rogers, Carla Maree — 2008-03-11T13:12:12Z

In broad terms, parentification can be defined as a child taking on the role of parent to his or her own parents; though in reality the construct is more complex. Although related constructs (e.g. boundary transgressions, role reversal, ‘hurried child’) have been discussed in the literature for many years, the term ‘parentification’ per se is a relatively new one within the field of psychological research and empirical studies are still limited. When researching in the field of parentification, an issue that is apparent is the lack of adequate measures of parentification available for children and adolescents. The few measures of parentification that exist have been (a) retrospective (asking adults to recall levels of responsibility within their families of origin as adolescents) and/or (b) uni-dimensional (measuring parentification as a single score rather than taking into account different facets such as confidant to one’s own parents, mediator between conflicting parents, ‘pseudo-parents’ to siblings, or excessive household responsibilities). The first aim of the current research was to develop a reliable and valid multidimensional measure of parentification that was appropriate for completion by children and adolescents. The series of studies that follow utilise this newly developed parentification scale to examine parentification of adolescents aged 10-16 years from families undergoing parental divorce. A comparison group of children from two-parent continuously married (not remarried) families were included. A previously validated uni-dimensional measure of parentification, the Parentification Questionnaire – Youth (PQ-Y: Godsall & Jurkovic, 1995) was also used throughout the studies (although in the current sample, this measure was multidimensional, yielding two factors labelled Alienation and Tangible Tasks). Broad research goals of the studies are: 1. to examine parentification (and its association with family functioning and sibling relationship quality) from the perspective of multiple family members, 2. to explore parentification differences between families on variables of age, sex, birth order, family size and parental marital status, and 3. to assess the extent to which parentification affects adolescent psychological adjustment, and how burden of parentification may mediate the relationship between parentification and psychological adjustment. Parents and children aged 10-16 years from 304 families (127 divorcing; 177 married) were invited to participate in a 12-month study of parentification that included questions about demographics, family responsibilities, family functioning, adolescent adjustment, and sibling relationships. In addition, in divorcing families, both parents and one child (target child) were invited to be interviewed regarding their experiences surrounding the separation and divorce. The measure of parentification designed for the current research adapted the multidimensional, retrospective measure written by Mika, Bergner and Baum (1987). This new measure was labelled the Youth Parentification Scale (YPS), and findings suggest that it is a reliable measure of parentification in the current sample of married and divorcing families. Results revealed that children from divorcing families and girls reported higher levels of parentification (across various factors). Results on multiple perspectives within the family were mixed. In general, children were more likely than their parents to report higher levels of parentification within the family, although this effect differed slightly dependent upon parental marital status. Siblings who reported offering support to other members of the family also rated their relationship with their sibling as warmer: this result held true for both firstand second-born children. Additionally, both first- and second-born children agreed that parentification may affect the relative status/power between siblings. While few direct associations between parentification and adjustment existed, negative adjustment outcomes (higher anxiety, higher depression and lower self-esteem) were evident when the burden associated with increased responsibility was taken into account. Taking on the role of confidant to one’s parents, playing ‘pseudo-parent’ to one’s siblings, or feeling alienated within one’s family of origin was associated with higher levels of burden, which in turn led children to report higher depression and anxiety and lower self-esteem. Additionally, taking on a parentified role was associated with higher levels of burden, which in turn was associated with reports of lower levels of family functioning (i.e. lower intimacy, higher conflict, and a more controlling parenting style). The current research has implications for the development and refinement of future measures of parentification for use in empirical studies. The Youth Parentification Scale showed that different facets of parentification do seem to exist, and that offering comfort and support to mothers or fathers seems to have an association with various aspects of adjustment, sibling relationships and general family functioning. Alienation (a factor emerging from the PQ-Y), while not actually associated with increased responsibility or parentification per se, showed associations with parentification that indicate that this may be an important construct to include in future attempts at developing a comprehensive measure of parentification. Additionally, the current research unveiled findings that may have clinical importance. Findings revealed that while children from divorcing families did exhibit higher scores on various scales of parentification, outcomes were not necessarily worse for these children than for children within married families who were similarly parentified. Adolescence is a time of emotional growth when some age-appropriate adoption of adult responsibility is warranted; and in fact for children undergoing the transition of parental separation and divorce, adoption of extra responsibilities may be adaptive, perhaps even protective inasmuch as it may bring the child closer to parents during a time when anxiety about family dissolution is high. Further studies (preferably longitudinal) exploring the adaptive facets of parentification are warranted.

Adults’ Physically-Active Transport: A Population- and Destination-Based Perspective

Rachel Cole — 2009-03-06T11:24:40Z

Increasing population levels of physical activity is a key public health priority in combating chronic non-communicable diseases. Epidemiological evidence for the health benefits of moderate-intensity physical activity has aroused interest in active transport, particularly walking. Social ecological models, and specifically policy and environmental approaches to increasing active transport are core elements of public health goals. There is currently limited walking for transport data in Australia that can be analysed using public health criteria. There is some evidence that socio-demographic differentials may exist. Investigations of the correlates of walking for transport suggest that residents of neighbourhoods with greater population densities, more land use mix, greater street connectivity and better walking and cycling infrastructure, tend to walk and cycle more. The studies in this Thesis start to address some aspects of these knowledge gaps by focussing on the social, personal and environmental correlates of adults’ walking for transport. These studies aim to identify how active commuting and transport options might potentially be used to increase adult levels of health-enhancing physical activity, through increased walking. In doing so, it assists in increasing understanding about ways to link public health policy initiatives more strongly to the transport and urban-design fields, and to other sectors with an interest in active transport. The thesis begins with a literature review of the descriptive epidemiology and correlates of walking for transport. Chapter 2 is a secondary analysis of existing data from a statewide survey of adults. It reports socio-demographic variations in moderate to brisk paced walking for transport, and the contribution of walking for transport to health-enhancing physical activity, separately from walking for recreation. The results showed that rates of sufficient walking for transport using public health criteria (10% for men; 9% for women) were slightly less than those for walking for recreation or exercise (14% for both men and women). Few socio-demographic differences emerged in rates of walking for transport. Men aged over 60 years were significantly less likely to walk for transport. Walking contributed more toward meeting the current public-health guidelines among women (15% to 21%) than among men (6% to 8%). The Thesis then examines relevant issues associated with walking to two discrete destinations, within a defined local-community context. The first destination-type was primary schools (Chapter 3). In this study, the prevalence and duration of walking to and from school, together with perceived influences on doing so, were examined among parents of primary school children. Findings showed that, despite the overall low prevalence of walking to school by parents, health-enhancing benefits may be achieved, even when other modes of transport are used in conjunction with walking. Walking was a common (28%) mode of transport for journeys less than two kilometres. Eighteen percent of parents who travelled by modes other than walking also walked for at least 10 minutes. Significantly greater proportions of parents who walked for at least 10 minutes: had only one car in their household; had a child who attended a government school; did not have a driver’s licence; had 10 years or less of education; and, lived within two kilometres of the school. Factors perceived by parents as influencing walking to and from school were: being physically active; safety concerns for the child walking alone; not having to park; walking being the child’s preferred option; there being too much motor vehicle traffic; and, their child’s age and road sense. The second destination-type examined was tertiary education institutions (Chapter 4). In this study, associations of stages of motivational readiness for active transport with perceived barriers and incentives to walking to and from university among students were examined. Common barriers to walking were long travel distances, inconvenience and time constraints. Common incentives were shorter travel distance, having more time, supportive infrastructure and better security. Those not considering active commuting (pre-contemplators) were significantly more likely to report shorter travel distance as an incentive compared to those in the contemplation-preparation stage. Those in the contemplation-preparation stage were significantly more likely to report lack of motivation, inadequate infrastructure, shorter travel distance and inconvenience as barriers; and, having more time, supportive infrastructure, social support and incentive programs as enablers. Chapter 5 explores ways of linking public health policy initiatives with other sectors. Structured interviews with senior and middle level administrators from public, private and community groups were used to assess perceived barriers and enablers to active transport. Key themes emerged from the study relating to infrastructure delivery, public transport services, walk- and cycle-friendly community attributes, political leadership and government coordination, and societal travel norms and culture. There were also themes relating to limited resources and limited relevant technical expertise, institutional and practitioner cultures, and agencies not identifying with their roles in active transport. Broader intersectoral policies and cross-government initiatives were seen to hold promise, including economic incentives and built environment guidelines, campaigns targeting public attitudes and opinions, and community participation in policy-making. The findings from these studies and the implications for increasing physical activity through walking for transport are discussed in Chapter 6. These findings have potential to be used to inform intervention approaches, study initiatives and future research directions across key sectors for specific subgroups and particular destinations. Physical activity strategies and programs could feasibly be designed within community and organisational settings to increase adults’ rates of participation in walking for transport.

Advanced Data Mining Methods for Electricity Customer Behaviour Analysis in Power Utility Companies

Ms Anisah Nizar — 2008-11-13T21:37:27Z

Advanced Techniques for Power System Stability Analysis

Jian Ma — 2008-07-10T09:57:46Z

Advances in Cross-Entropy Methods

Thomas Taimre — 2009-05-14T11:34:27Z

The cross-entropy method is an established technique for solving difficult estimation, simulation, and optimisation problems. The method has its origins in an adaptive importance sampling procedure for rare-event estimation published by R. Y. Rubinstein in 1997. In that publication, the adaptive procedure produces a parametric probability density function whose parameters minimise the variance of the associated likelihood ratio estimator. This variance minimisation can also be viewed as minimising a measure of divergence to the minimum-variance importance sampling density over all members of the parametric family in question. Soon thereafter it was realised that the same adaptive importance sampling procedure could be used to solve combinatorial optimisation problems by viewing the set of solutions to the optimisation problem as a rare-event. This realisation led to the debut of the cross-entropy method in 1999, where it was introduced as a modification to the existing adaptive importance sampling procedure, with a different choice of directed divergence measure, in particular, the Kullback-Leibler cross-entropy. The contributions of this thesis are threefold. Firstly, in a review capacity, it provides an up-to-date consolidation of material on the cross-entropy method and its generalisations, as well as a collation of background material on importance sampling and Monte Carlo methods. The reviews are elucidated with original commentary and examples. Secondly, two new major applications of the cross-entropy methodology to optimisation problems are presented, advancing the boundary of knowledge on cross-entropy in the applied arena. Thirdly, two contributions to the methodological front are (a) an original extension of the generalised cross-entropy framework which enables one to construct state- and time-dependent importance sampling algorithms, and (b) a new algorithm for counting solutions to difficult binary-encoded problems.

Advances in power system small signal stability analysis considering load modeling and emerging generation resource

Yateendra Mishra — 2009-04-08T12:51:50Z

With the increasing complexity of the power system, electromechanical oscillations are becoming one of the major problem. Several blackouts have been reported in the past due to insufficient damping of the oscillatory modes. The starting point to avoid catastrophic behaviors would be to simulate actual power system and study the response of the system under various outages leading to blackouts. Recently, it has been identified that appropriate modeling of the load is necessary to match the actual system behavior with the computer simulated response. This research throws some insight into the detailed load modeling and its impact on the system small signal stability. In particular, Composite load model is proposed and its effect on the system small signal stability is investigated. Modeling all the loads in a large power system would be a cumbersome job and hence the method for identifying the most sensitive load location is also proposed in the thesis. The effect of load modeling on the eigenvalue movement is also investigated. The low damped electromechanical modes are always undesirable in the large inter-connected power systems as they might get excited under some event leading to growing oscillations. Proper damping of these modes is essential for effective and reliable system operation. Power system stabilizers have been proved to be an effective way of damping these electromechanical modes. The optimal number and location of PSS to effectively damp the modes via improved Differential algorithm is proposed. Moreover, the effect of TCSC, series compensated FACTs device, on enhancing the system damping is investigated. A fixed order model matching technique is presented to design a damping controller for the TCSC. With the increasing global pressure for reducing carbon emissions, there is a great amount of interest in the renewable sources of energy, particularly Wind Energy Conversion Systems. Of all the present methods of wind generation systems, Doubly Fed Induction Generation (DFIG) based wind farms are gaining popularity. The comparison of various methods of wind generation techniques is presented. In particular, the impact of DFIG based wind farms on the system small signal stability is investigated in this work. Co-ordinated tuning of the controllers is performed using Bacterial Foraging Technique, which is another member of Evolutionary algorithms. Damping controller for the DFIG system is proposed to enhance the damping of the electromechanical modes. Results have proved the effectiveness of the control methodology. The contributions made in this thesis could be utilized to promote the further development of the damping controllers for large power systems.

ADVANCING THE EVALUATION METHODOLOGY FOR COMMUNITY-BASED INJURY PREVENTION PROGRAMS: PERSPECTIVES FROM A CASE STUDY EVALUATION

Yorkston, Emily Kate — 2008-11-21T16:02:34Z

Background: The traditional public health approach to injury prevention and control is founded on a causal model of injury that focuses on individual-level risk factors relevant to the exchange of energy that causes anatomical injury. Contemporary epidemiology recognises the role of macro-level physical and social determinants in injury aetiology and therefore the ecological approach, which examines the population level effects on health outcomes, has become more frequently employed. The ecological approach underpins the community-based model of injury prevention. Despite implementation of this model on a global scale, few evaluations demonstrate the effectiveness of the community-based model to reduce injury outcomes. Existing evaluations are limited by methodological flaws including inadequate evaluation timeframes, poor selection of community controls, use of poor quality data sources and failure to match the evaluation approach with the ecological nature of the community-based model. Current evaluation methods do not adequately account for the effect of social variables upon injury rates. Aim: The aim of the thesis is to advance evaluation methodology for community-based injury prevention programs by: designing and implementing a case study evaluation program consistent with current best practice methods for community-based injury prevention programs; using the quantitative data from the case study evaluation to illustrate threats to the validity of results obtained by this methodology; and developing an improved methodology for application to future evaluations of community-based injury prevention programs. Methods: A quasi-experimental study which measured changes in process, impact and outcome evaluation components in two matched intervention and control community pairs was conducted between May 2003 and September 2005. Program implementation activities were recorded by the project officers in electronic process logs. Impact evaluation included assessment of community capacity before and after program implementation using a Community Capacity Index, and measurement of pre- and post-implementation prevalences of safety behaviours and injury risk factors using self-report surveys. Outcome evaluation included injury data from emergency department and hospital admissions datasets for thirteen years pre-implementation and eighteen months after program implementation commenced. Effectiveness of the case study programs was assessed by comparing predicted and observed injury rates. A generalised estimating equation model of childhood injury rates was created using state wide data to control for changes in social variables within the two intervention communities. Results: The effect of the prevention program on the intervention communities was minimal. Little change in process activities was demonstrated. Community capacity improved slightly in both communities; however changes to safety behaviour and injury risk factor prevalence were limited. Many of the significant changes represented increased injury risk. Changes to outcome measures were also limited. Observed childhood injury rates were within predicted ranges for Intervention and Control Community One and Intervention Community Two, but increased beyond the predicted range in Control Community Two. The GEE model indicated the intervention was associated with statistically non-significant decrease of 0.07 injuries/10,000 0-4 year olds (95%CI: -0.24, 0.10) in logarithmically transformed injury rates (p=0.40).The GEE model found a significant relationship between childhood injury rates and first (p<0.001) and second order time components (p<0.001). Rurality was significantly associated with childhood injury rates, where childhood injury rates increased by 0.06 injuries/10,000 0-4 year with each increasing unit of remoteness (p<0.001). The model found an increase of 2.69 injuries/10, 0000 0-4 year olds as the proportion of married people within the region increased (p<0.001) and a decrease of 1.84 injuries/10,000 0-4 year olds as the proportion of Indigenous residents increased (p<0.001). There was also a significant association between the proportion of Indigenous residents, time and childhood injuries (p<0.002). When controlling for social variables, the intervention was associated with a decrease of 0.09 injuries/10,000 0-4 year olds (95%CI: -0.29, 0.11) in logarithmically transformed injury rates, however this decrease was not significant (p=0.36). Conclusion: This thesis has explored the need to consider the effect of social level variables on rates of childhood injury. The lack of identification, data collection and analysis of social variables when evaluating community-based injury prevention programs may explain the lack of observed effectiveness of community-based programs. The current best practice methodology for evaluating community-based injury prevention programs can be improved by ensuring the effect of social variables are accommodated with the analytic model of the evaluation.

Advancing the Interhemispheric Switch Model of Perceptual Rivalry

Trung Thanh Ngo — 2009-04-07T02:29:47Z

Perceptual rivalry refers to visual phenomena that are characterised by alternations between different percepts, despite an unchanging sensory input. Two common types of perceptual rivalry are (i) reversible figures — two-dimensional stable images that when viewed, are perceived to switch between different interpretations, and (ii) binocular rivalry — the alternations in image dominance resulting from the presentation of conflicting stimuli, one to each eye. Several investigators have suggested that these rivalling phenomena are mediated by similar neural mechanisms. Such a view, however, has not only been inadequately substantiated, but has also yet to be assessed in the context of a directly testable neurophysiological model. Miller and Pettigrew have proposed a novel, high-level interhemispheric switch (IHS) explanatory model of binocular rivalry. This model conceptualises the perceptual alternations as being mediated by alternations between one hemisphere’s selected image and the other hemisphere’s selected (rival) image. To assess their hypothesis, caloric vestibular stimulation (CVS) was used. CVS is a simple, inexpensive, and non-invasive brain stimulation technique that unilaterally activates high-level attentional areas. In accordance with the IHS model, CVS was found to significantly affect predominance (the duration that one image is perceived relative to the other, within a given viewing period) during conventional binocular rivalry with horizontal/vertical gratings and with orthogonal oblique gratings. The present thesis therefore aims, through the use of CVS, to extend this IHS model of binocular rivalry to reversible-figure alternations and propose a general IHS model of perceptual rivalry. Chapter 1 provides a detailed literature review of the field within the context of comparing both perceptual rivalries. In Chapter 2, investigations are presented on two different reversible figures — the perspective-reversing Necker cube and the figure–ground reversing Rubin’s vase–faces illusion. In these experiments, CVS was found to significantly change observers’ predominance compared to their baseline predominance. These results demonstrate that interhemispheric switching also mediates the alternations of these visual phenomena, in addition to binocular rivalry, thereby extending the IHS model to one of perceptual rivalry in general. Moreover, the findings are interpreted in a cognitive neuroscience context, including a novel proposal of a forebrain framework for the IHS model. Chapter 3 presents CVS experiments that address the issue of percept–to–hemisphere selection and the reproducibility of CVS effects, following Miller’s initial work on two types of conventional binocular rivalry. In planned analyses, significant predominance changes were not found in horizontal/vertical rivalry, oblique rivalry and Necker-cube rivalry. In post-hoc analyses that accounted for study-design differences between Miller’s original experiments and the present experiment, CVS was again not shown to induce significant predominance changes in any of the rivalry types. Assessment of directional predominance changes following CVS appeared to suggest an arbitrary selection of percept–to–hemisphere in all rivalry types, although no firm conclusions could be drawn from the obtained data on this issue. Nevertheless, the experiments further extend upon Miller’s earlier work by examining the inter- and intra-individual reproducibility of CVS-induced effects on predominance. Such reproducibility was found to be low and potential reasons for this are discussed. The experiments in Chapter 4 examine a type of binocular rivalry in which dichoptic presentation of Díaz-Caneja stimuli yields rivalry among four different stable images: half-field rivalry between the images presented to the eyes, and coherence rivalry in which aspects of each eye’s presented image are perceptually regrouped into rivalling coherent images. Each of these rivalries was found to occur for about half the given viewing time. Furthermore, CVS significantly shifted the predominance of perceived coherent images (coherence rivalry) but not half-field images (eye rivalry). This finding suggests that coherence rivalry (like conventional rivalry according to previous experiments) is mediated by interhemispheric switching at a high level, while eye rivalry is mediated by intrahemispheric mechanisms, most likely at a low level. In addition, it is proposed that Díaz-Caneja stimuli induce ‘meta-rivalry’ whereby these discrete high- and low-level competitive processes themselves rival for visual consciousness. The current thesis thus presents a novel meta-rivalry model of multistable binocular rivalry. It also presents the first direct evidence that interhemispheric switching mediates reversible-figure alternations, thereby supporting a generalised IHS model of perceptual rivalry. It is argued that both models provide a parsimonious exploratory framework within which specific predictions can be made and readily tested. Finally, the findings of all experiments in the current thesis are summarised.

ADVISORY EXPERT SYSTEM FOR PROCESS CONTROL

Meeuwissen, Christiaan Percival — 2008-04-24T12:11:01Z

Aeration due to Breaking waves

Cummings, Peter D. — 2008-11-21T16:50:31Z

The exchange of mass (gases, water & salts) between the oceans and the atmosphere is vital to the maintenance of life on earth. At high wind velocities most of this exchange is attributable to breaking wave entrained air bubbles. A vertical supported planar plunging jet experiment was used to model the entrainment process. The bubbles were detected with a dual tip conductivity probe and a video camera. At plunging jet velocities below 1.0m/s there is no bubble entrainment. This inception velocity appears to have a Froude and Weber number scaling for large rough turbulent jets. At jet velocities up to 5m/s air appeared to be entrained via intermittent air cavities at the jet - plunge pool intersection. The entrained air packets subsequently break in the two phase free shear layer under the entrainment point. At higher jet velocities there may be partial penetration of the aerated jet surface via pulsating induction cavities plus air entrainment via jet self aeration before impact. Plunging jet air flow data displays the different types of entrainment mechanisms. Mono-phase diffusion models can be successfully adapted to describe the shear layer developing zone. The diffusion of the air bubbles is approximately a Gaussian self similar process. The mean bubble velocity profiles can be modelled using the Goertler Error function or Hyperbolic Tangent models. The bubble spectra is approximately Lognormal with a geometric mean diameter of 1.0-2.0mm for a range of jet velocities. A bubble Weber number is found to model the maximum bubble size of approximately 10mm diameter. An original adaptation of the potential flow solution for the vortex sheet is shown to be a simple and reasonably accurate finite amplitude model for water surface gravity waves, especially in deep water. This model has some interesting features, such as both vertical and horizontal asymmetry and standing wave water profile modelling. A simple and possibly insightful model of wave growth due to the wind is introduced, using a constant sea surface Reynolds number U*.sqrt(L.F)/Gamma , where U* = wind friction velocity, L = wavelength, F = fetch, and Gamma = wave field vortex circulation per wavelength. The results may have application in the modelling of air - sea gas exchanges, predicting breaking wave forces on structures and the use of the planar plunging jet as an aeration device in industry.

Aerothermodynamic Simulation of Subscale models of the FIRE II and Titan Explorer Vehicles in Expansion Tubes

Capra, Bianca Rose — 2008-11-21T15:53:03Z

Scale models of the terrestrial re-entry probe FIRE 11, and the proposed Titan aerocapture vehicle Titan Explorer, were tested with regards to their aerothermodynamic environment in the expansion tubes at The University of Queensland. Test models were sized from their respective flight vehicles using binary scaling to ensure similitude was maintained between the flight and experimental flowfields. The FIRE I1 model had a length scale of 1:27.7, maximum diameter of 24.28mm and nose radius 33.78mm. This model was orientated at a 0" angle of attack and was designed to simulate the flight heating environment 21.75s after re-entry, where radiation contributed an estimated 17% - 36% to the total heat transfer. The Titan Explorer test model was a 70" sphere-cone and was designed to simulate a peak heating condition occurring 253s into an aerocapture manoeuvre at Titan, where radiative heat transfer was estimated to contribute more than 80% to the aerothermodynamic heating. The model was sized to a length scale of 1:40.8 giving a maximum diameter of 94.46mm with nose radius of 22.37mm. The Titan Explorer model was tested at both a 0" and 16" angle of attack with lift-up in a simulated Titan atmosphere consisting of 5% CH4 and 95% N2. Both models were manufactured from steel and contained forebody heat flux instrumentation for measurement of the aerothermodynamic heating. A new gauge was developed for the separation and detection of the radiative component of heat transfer to the Titan Explorer model where non-negligible amounts of radiation were present on the test model. This gauge contained two thin-film nickel temperature sensing elements housed in a brass holder. Sensing elements were separated from direct contact with the flow via appropriate optical windows. All reflecting surfaces of the radiation gauge, with the exception of the nickel element, were painted in flat black paint to minimise spurious reflections. Total heat transfer on both models was measured with fast response type-E surface mounted thermocouples. From an analysis of both a transparent and absorptive gas it was proposed that absolute aerothermodynamic radiative heat transfer will remain invariant between an experimental model and the flight vehicle, provided binary scaling was maintained, and radiation was uncoupled or weakly coupled to the flow. This necessitated the treating of each mode of heat transfer independently when scaling flight data to the experimental models and vice versa. A parameter referred to as the reduced flight value was developed that allowed experimentally measured heat transfer to be directly compared with the appropriately scaled flight heating rates. The reduced flight value also allowed for estimation of flight vehicle heating rates from experimentally measured total and radiative heat transfer. Stagnation point results from the FIRE I1 testing successfully demonstrated the ability of expansion tubes to recreate the aerothermodynamic environment of flight vehicles. At this location an average of 14.28&7%kW/cm2 of total heat transfer was experimentally measured. This was shown to have a good agreement of between 5% - 15% with both empirical convective heating correlations and the reduced flight values scaled from the flight data. Total heat transfer values measured at two radial locations 11.4" and 18.7" from the nose were 17.11&7%kW/m2 and l7.14f 7%kW/cm2 respectively and were substantially higher than both the stagnation point and reduced flight values. The high heating rates experimentally measured at these locations were attributed to the boundary layer becoming turbulent on the test model as a result of surface roughness and was estimated likely to occur at approximately 8.4' from the stagnation point. Aerothermodynamic radiative heat transfer was successfully separated and measured on the Titan Explorer test model. It was shown that this measured radiative heat transfer was a direct result of the addition of CH4 into the test gas which promoted the formation of the strong radiating particle cyanogen, CN, in the shock layer. At the design orientation of a 16" angle of attack with lift-up in a simulated Titan atmosphere, 20.8% 14%W/m2 of surface radiative heat transfer was measured at the flow stagnation point. This represented 4% of the total heat transfer of 510&7%W/cm2 recorded by the stagnation point thermocouples. A similar contribution of radiative heat transfer was measured with the model orientated at a 0" AOA when the radiation gauge was positioned 19.6mm vertically below the sphere-cone apex. In this orientation 21.6% 14%W/m2 of radiative heat transfer was measured compared to the local total heat transfer of 420W/cm2.

Aerothermodynamics of Hypervelocity Toroidal Aerobrakes

Ivy Lourel — 2008-12-01T18:38:47Z

Aetiological investigations in idiopathic scoliosis

Day, Gregory A. — 2008-06-19T09:54:11Z

Aetiology of Obesity in Australian Families

Belinda Cornes — 2008-03-28T15:13:24Z

Excessive weight can have a severe impact on health as well as creating a significant economic burden. Obesity is reaching epidemic proportions, but the mode of inheritance of obesity and its underlying complexity remains largely unresolved. Thus, the aim of this research project was to provide a further understanding of this condition in an Australian adolescent and adult population. Qualitative and quantitative differences in genetic and environmental influences affecting body mass index (BMI) in males and females, during development were examined. Structural equation models were fitted to longitudinal data collected at ages twelve, fourteen and sixteen from 470 monozygotic (MZ) twin pairs and 673 dizygotic (DZ) twin pairs. In addition, it is generally known that some genetic differences are only exposed in the presence of certain environmental stressors, such as the effects of parity and age on post-partum obesity. Therefore, models were fitted to data from 11, 915 female twins and their sisters from whom reproductive history was available in order to assess the changes in magnitude of genetic and environmental variation in female BMI due to these variables. To detect quantitative trait loci (QTLs) influencing adolescent BMI, up to 1133 highly polymorphic microsatellite markers were typed across the genome in a sub-sample of adolescent twins, their parents and siblings. Because gene mutations for some genetic disorders affecting body weight may manifest during childhood, univariate linkage analysis were applied to test for linkage between marker loci and BMI at twelve, fourteen and sixteen across the genome. Additionally, genes involved in pathways regulating body weight may operate differently in men and women. Therefore, a genome-wide linkage analysis allowing for sex difference in linkage patterns was performed in order to identify QTLs influencing BMI which may differ between adult males and females. Genetic factors contributed strongly to BMI in adolescent twins, accounting for approximately ninety percent of phenotypic variation at twelve, fourteen and sixteen years of age. In addition, the majority of this genetic variance was transmitted from age twelve to ages fourteen and sixteen. Sex differences in the size of genetic innovations at ages fourteen and sixteen suggest that the genetic variation in weight regulation is different in males and females. The presence of environmental influences in males and females may reflect the effects of lifestyle activities during adolescents such as severe exercise and diet regimes. Structural equation models exploring the effects of parity and age on female BMI revealed that genes become more important in the variation in BMI as parity increases. The ability to retain weight for lactation and support for foetal growth possibly reflects an evolutionary advantage in times when it was a necessary condition of survival. Unique environmental influences were also important in the variation female BMI across parity and age, possibly reflecting lifestyle factors and individual responses to social attitudes towards weight gain. Genome-wide linkage analysis in adolescent twins revealed strong evidence for linkage on chromosome 14q12-q13 at age fourteen (logarithm of odds (LOD) = 3.71, p = 0.000018) and suggestive linkage in the same region in sixteen year old twins (LOD = 2.46, p = 0.00038) which has been previously implicated in adiponectin in Northern Europeans. Chromosome 6p12 yielded a suggestive LOD = 2.95 (p = 0.00012) which harboured a known gene responsible for rebound weight gain. Evidence for replication (LOD = 1) at other areas of the genome was also observed, including 1, 4, 10, 11, 13 and 20, which have been previously associated with obesity in other studies, being LEPR, UCP1, OB10P, BMIQ3 and BMIQ6, respectively, although we did not have time to genotype these to test for association in our samples. The use of a genome-wide linkage analysis allowing for sex difference in linkage patterns identified areas on chromosome 8 and 20, providing us with evidence that some of the genes responsible for BMI may have different effects in adult men and women. Results revealed a suggestive linkage peak (-log10p = 3.13; equivalent to LOD = 2.19, p = 0.000741) at 12q24 (-log10p = 3.02; equivalent to LOD = 2.08, p = 0.000955), that has been implicated in weight in a wide range of populations and where non-insulin-dependent diabetes mellitus, a consequence of obesity, has also been mapped. We also identified many peaks near the threshold for replicating an existing finding (-log10p = 2; equivalent to LOD = 1.18, p = 0.01) in many areas across the genome that are within regions previously identified by other studies, as well as in locations that harbour genes known to influence weight regulation. Finally, the significances of these results are discussed and future directions are considered including association analysis on single nucleotide polymorphisms (SNPs) across six candidate genes: LEPR, GNβ3, UCP2, UCP3, FTO and INSIG2 which have previously been associated with obesity or BMI. We typed seventeen SNPs and performed analyses in a sample of 4494 MZ and DZ twins. Significant association was found for rs9939609 (A/T polymorphism) of the FTO gene. In our data, each additional copy of the rs9939609 A allele increased mean BMI by approximately 0.14kg/m2 in an apparent additive manner, comparable with recent published results from population-based studies in white European children and adults.

Aetiology of pineapple mealybug wilt disease in Australia

Cherie Faye Gambley — 2008-11-21T10:33:29Z

Affect and Performance: A Multilevel Analysis of Moderators and Mediators

Elisha Frederiks — 2009-10-06T20:44:20Z

This thesis examined the intra-individual relationship between state affect and task performance, with an emphasis on a) the moderating effects of trait affect and task difficulty; and b) the mediating effects of cognitive and affective regulation. Theory and empirical research from the emotion, motivation, and personality literatures was integrated to develop a multilevel model of states, traits, and situational factors as predictors of task performance. Data from five studies were analysed using single- and multi-level techniques to test the hypothesised model of relationships. The findings are reported within three manuscripts, which comprise the body of this thesis. Manuscript 1 presents validation evidence for the psychometric instruments used to measure the self-regulatory components of the model. Three studies (N = 758) were conducted to examine the nomological network of cognitive and affective regulation. In parallel, two new self-report scales were developed to operationalise these constructs within a repeated measures paradigm. The three studies demonstrated that the new cognitive and affective regulation scales were uniquely associated with other self-regulatory, personality, affective and achievement variables at the intra-individual and inter-individual levels. Study 1 provided evidence for the unidimensionality, internal consistency, and construct validity of each scale. Study 2 replicated and extended construct validity evidence using a different sample and performance domain. Study 3 established the utility of each scale for assessing intra-individual variability in cognitive and affective regulation, and their ability to predict performance within individuals. In sum, the three studies suggested that the new measures of cognitive and affective regulation were psychometrically adequate for use in model testing. Manuscripts 2 and 3 tested the intra-individual relationship between state affect and task performance, with a focus on the moderating effects of trait affect and task difficulty (Manuscript 2), and the mediating effects of cognitive and affective regulation (Manuscript 3). Each manuscript analysed different portions of data from two laboratory experiments (N = 182). In each experiment, participants performed multiple trials of an air-traffic control simulation that varied in task difficulty at the inter-individual (Study 4) or intra-individual (Study 5) level. Trait positive and negative affect were measured before the task, whereas state positive and negative affect, cognitive and affective regulation, and task performance were measured at repeated intervals over practice. In Manuscript 2, hierarchical linear modelling demonstrated that state positive affect was positively related, whereas state negative affect was negatively related, to task performance at the intra-individual level of analysis. As hypothesised, the strength of these affect-performance relationships was significantly moderated by trait affect and task difficulty. In both studies, the positive intra-individual relationship between state positive affect and performance was stronger for individuals with high (versus low) trait positive affect, particularly when task difficulty was high (versus low). In contrast, the negative intra-individual relationship between state negative affect and performance only emerged for individuals with low (versus high) trait negative affect, regardless of the level of task difficulty. In Study 4, the intra-individual relationship between state negative affect and task performance was also more pronounced when task difficulty was high (versus low). In Manuscript 3, multilevel multiple-mediation modelling demonstrated that cognitive regulation significantly mediated the intra-individual relationship between state positive affect and performance in both studies, alongside the intra-individual relationship between state negative affect and performance in Study 4. Unexpectedly, affective regulation failed to mediate either of these affect-performance relationships. However, state positive affect was positively related to affective regulation in both studies, whereas state negative affect was positively related to affective regulation in Study 5. Overall, this thesis makes theoretical, empirical and methodological contributions to understanding how affect relates to performance at the intra-individual level of analysis; and for whom, when, and why these relationships emerge. Within a multilevel framework, it integrates interdisciplinary perspectives to identify the affective determinants of performance from two levels of analysis. The results demonstrate that state positive and negative affect can differentially predict intra-individual variability in task performance, and that these effects may a) depend on trait affect and task difficulty; and b) be partially explained by cognitive regulation. These findings emphasise the importance of adopting a multilevel, repeated measures paradigm to examine how affective states, traits, and task demands interactively predict task performance. There is scope for extending this research further by investigating a broader range of moderating and mediating constructs. Practical implications and directions for future research are discussed.

Aftereffects of auditory spectral “motion”: Perceptual dissociations suggest a neural processing hierarchy

Lacherez, Philippe F. — 2008-09-19T14:16:41Z

Aged Horse Health, Management and Welfare

Thomas Mcgowan — 2009-08-31T06:33:34Z

Abstract Background: Aged horses make up an important portion of the equine industry in Australia but have not been the subjects of detailed research. Issues relating to aged horse health, management and welfare are still largely unknown. Horses live up to 40 years, but many are retired before reaching twenty years of age thus making a large discrepancy between productive verses unproductive life. Based principally on reviews of veterinary hospital records, there has been a reported increased occurrence and severity of a range of diseases in aged horses. The increased prevalence of disease, potential for reduced perceived value and lack of regular riding may contribute to reduction in the type and quality of management practices utilised in this population resulting in compromised welfare of aged horses. Aims: By way of an owner-based survey, the first aim was to examine the demographics of aged horses, their management, the prevalence of clinical signs of disease and owner reported health or welfare issues. Using a detailed veterinary clinical examination and appropriate laboratory tests, the second aim was to investigate the prevalence and risk factors of more common health disorders, prevention or management of these disorders and how diseases or other factors affect survival. Further, this study aimed to determine owners’ opinions relating to euthanasia of aged horses and to correlate these opinions with the personalities of the owners themselves. Methods: Owners of horses aged 15 years and older were contacted via equestrian organisations in Queensland, Australia and asked to complete a questionnaire on key information about the horse (e.g. age, breed, sex, and colour), use, management strategies, use of equine health care providers, clinical signs that the horse may be demonstrating, known diseases that the horse may have experienced or be experiencing, and identify any health or welfare issues they believed were important for horses aged 15 years or greater. From this population, a subsample was selected with these horses subjected to a thorough clinical examination, dental and ocular examination and blood tests for routine haematology, serum biochemistry, ACTH, α-MSH and insulin concentrations. Owners of the subsample of horses were asked to complete a questionnaire on their opinions of euthanasia of aged horses as well as complete a self assessment personality test. One to four years after the original survey, owners were contacted to gather additional information about the horses’ survival/death and if death had occurred the events and causes related to it. Analysis: Data was managed in Microsoft Access and Excel. Descriptive, univariate and multivariate analyses were performed using SPSS, Minitab and Stata. Univariable and multivariable regression modelling and survival analysis were performed where appropriate. Results: Horses aged 15 years or greater in Queensland represented ⅓rd of the total horses owned in the population. The median age of the horses was 20.7 years (IQ range 17-23, min 15, max 44). Owners were able to identify many clinical signs exhibited by their horses, with 83% of horses having at least one reported clinical sign of disease. But, many signs had apparently been overlooked, with only 35.2% of horses reported by the owners to have a known disease or disorder. Further, there was a large disparity between the prevalence of disease by owner reports compared to veterinary examination. For example, owner reported dental disease was 0.5% while moderate to severe dental disease occurred in 46% horses examined. Univariable and multivariable analysis identified many associations between disease and horse factors, management factors and clinical signs, with many diseases significantly related to increasing age. There was considerable variation in the level of owner reported professional and other health care strategies. In the preceding 12 months, 90% had received hoof care, 67% had received dental care, and 50% were vaccinated, while only 39% had received veterinary care. Despite this owners expressed concern about the health and welfare of their horses. The majority of owners, 91.6% (491/536), responded with at least one reply to a question about which they thought were the most important health issues in aged horses. Owners were most concerned about weight loss (maintaining the horse’s condition), arthritis/lameness and teeth and dental care. The major influences on the decision to euthanase involved animal welfare and quality of life and owners were cognizant and concerned about these factors relative to their horses. Of the 766 horses that were followed for survival, 13.2% had died. The median survival time was 777days. Age, breed of horse, region of residence, diagnosis of equine Cushing’s syndrome, being owned by Riding for the Disabled and reported history of difficulty eating were all significantly associated with decreased survival. Conclusions: This is the first major population study of aged horses in Australia. The aged horse population is a large sub population of the Australian horse population. This study has highlighted many aged related diseases and their specific risk factors. Owners demonstrated concern for the health and welfare of aged horses, but a lack of appropriate identification of many diseases by owners and limited veterinary care suggest a need for increased client communication and veterinarian-client interaction.

Ageing and Uncertainty: An Exploration of Age Related Patterns of Information Processing in Working Memory in Response to Uncertainty

Stephens, Stephanie — 2008-11-21T16:17:28Z

The present study was developed within the information theory, working memory, and cognitive ageing paradigms. The overall aim of the present study was to investigate the age related differences in the patterns of processing uncertainty within the theoretical construct of working memory, particularly the central executive, the episodic buffer, and the visuospatial sketchpad. The uncertainty associated with responding to stimuli is a complex construct that has received little attention in either the ageing literature or the working memory literature. The present study developed choice reaction time tasks based on the findings of Hick (1952) and Hyman (1953), in which the participants choice reaction time to a stimulus was shown to depend on three main variables. These three variables were found to vary the uncertainty associated with responding to a stimulus. The first variable was the stimulus set size. The number of stimuli was operationalised by the number of locations, four or eight, from which stimuli could appear. The second variable was condition probability. The currently appearing stimulus could appear from any one of four or eight locations. The current stimulus appeared with a probability equal to the other stimuli appearing in the condition, or appeared with a probability that could be different to the probabilities of other stimuli appearing in the condition. Thus, the current stimulus could appear within an equiprobable or a nonequiprobable condition. The third variable was the probability of appearance of the current stimulus. In the present study the current stimulus probability was manipulated to be either 0.250 or 0.125. These variables were manipulated in order to investigate the effect of responding to uncertainty across the healthy adult lifespan. In general, increasing age increased choice reaction time in response to the current stimulus under all experimental conditions, and increasing choice number significantly increased choice reaction time for all age groups. The literature review in chapter 1 highlighted the difficulties in assessing age related response differences in tasks that measure executive processes. In this chapter it is suggested that the methodology used in choice reaction tasks, developed within the information processing and uncertainty paradigm, may provide an insight into how and what changes occur to executive processing over the healthy adult lifespan. The results in the present study were interpreted within the theoretical structure of Baddeleys (2000b) model of working memory. This gave an explanatory framework to the age related patterns of choice reaction time responses. The experiment in chapter 2 examined the second variable, condition probability. The differences in choice reaction time responses between an 8 choice equiprobable condition and an 8 choice nonequiprobable condition, and between a young and an old age group, were explored. There was a significantly faster choice reaction time in response to the 8 choice nonequiprobable condition for both age groups. However, there was a disproportionately faster choice reaction time response to the 8 choice nonequiprobable condition by the older age group. The results suggested that the uncertainty associated with responding to stimuli was not only dependent on the equiprobable or a nonequiprobable condition in which the current stimulus appears, but also vulnerable to the effects of age. The results suggested that an episodic buffer (Baddeley, 2000b) supplies a central executive with precise information concerning condition probability. The choice reaction time responses indicated that a calculated amount of information using the probabilities of appearance of the stimuli does not explain the total uncertainty associated with the stimulus. The experiments reported in chapter 3 used single response tasks and chapter 4 used dual response tasks. These experiments examined condition probability again, along with the first variable, effect of choice set size, and the third variable, the current stimulus probability. Healthy adult participants aged from late teens to eighties were included. The choice reaction time responses in nonequiprobable conditions, compared to equiprobable conditions, were faster in response to both stimuli probabilities. Responses to the stimulus probability of 0.125 in the nonequiprobable conditions in both single and dual tasks were always significantly faster compared to the stimulus probability of 0.250 for all age groups. The older age groups choice reaction times were disproportionately slower in response to the stimuli of probability 0.250, compared to 0.125. This suggested that the central executive retains priority in responding to stimuli with a low probability, 0.125, in older age groups. The disproportionate response by the older age groups to stimulus probability, compared to the younger age groups, also suggested that the episodic buffer may not be as affected by increasing age as other working memory components. This also suggested the information held in the episodic buffer affects the speed of processing. The choice reaction time response patterns to both stimulus probability and condition probability were the same in the dual task conditions, compared to the single task conditions, for all age groups. The experiment in chapter 5 addressed the issue that the choice reaction time results were based on a small number of stimulus presentations per trial, and the response patterns may not be able to be maintained over a longer trial period. Thus, the temporal stability of the response to uncertainty was examined. Results were consistent with the proposal that there is temporal stability in processing uncertainty by all age groups in an extended task, and that the results did not arise because the choice reaction time patterns were a results of shorter trials requiring less sustained effort. Chapter 6 summarised the results found in the present study and interprets those results in terms of Baddeleys (2000b) theoretical model of working memory, age related response decrements, and uncertainty. The main conclusions were that first, the fastest choice reaction time, for all age groups, is in proportion to the greater uncertainty associated with the stimulus, and in proportion to the greater uncertainty of the context in which the stimulus appears. Second, the gradual age related slowing of choice reaction time responses to the current stimulus indicated a gradual increase in the speed of decision processing within the central executive. Third, the results indicated the information temporarily held in the episodic buffer affects the speed of processing. Fourth, the results indicated that the episodic buffer ages less than the central executive. The uncertainty associated with responding to stimuli with differing probabilities of appearance was found to be an excellent instrument in examining aged changes in working memory.

Agency, discourse and academic practice: Reconceptualising international students in an Australian university

Kettle, Margaret Anne — 2008-11-21T15:20:33Z

My research project is the case study of a Master of Education course called Debates in Education and Leadership as told through the accounts of six international postgraduate students. Most were undertaking study in Australia for the first time. The study is a detailed investigation of the students representations of and participation in course practices. It is a discourse analysis with a focus on social practice, power relations and knowledge. The study describes academic activities within the course and the lecturers and students ways of interacting and acting, of representing knowledge and the social world, and of being. The analysis draws out the students readings of preferred ways of doing academic work and identifies the programs of strategic action that they undertook as a result. The genesis of this study lies in my experiences with students in academic English programs. My aim in the study is to build a comprehensive understanding of student practice with a view to challenging the reductive images in the research literature and circulating in popular discourse. Utilising ethnographic perspectives, an extensive corpus of the students representations of the course was collected, with triangulation provided by the lecturer and a body of written materials. The data includes interviews, videoed classroom sessions, a written archive of course documents including the course outline, teaching evaluation forms, student assignments and lecturer feedback, email communication between the lecturer and students, and field notes. The students representations of the course emphasise English and particular academic activities such as writing assignments and voicing ideas in class which require new skills, new identities, new ways of viewing the world, and new interaction patterns. The other prevalent themes are the teaching and issues related to the self. Contrary to previous work which has tended to represent students as fixed entities challenged by cultural and academic change, the students in this study are found to be engaged in a project of change and the uptake of practices that is characterised by a gradual coming to do and be. The analysis finds that the lecturers teaching approach is significant in facilitating both of these efforts. English is a salient factor and the students respond strategically to the discourse that draws together English and academic practice in a formidable regime of expectations and requirements. The analysis details the students recognition of and response to this discourse and its associated practices. Above all, the students undertakings and engagement in the course are found to be part of a larger project of personal transformation as they harvest opportunities made available in the prevailing context of internationalised higher education. The implications for the provision of international education by Australian universities are discussed.

Age-related changes in sensori-motor function, postural stability, functional balance and mobility.

Low Choy, Nancy — 2008-11-03T13:50:10Z

Agitators and Patriots: Cultural and Political Identity in Queensland's Spanish Communities, 1900-1975

Robert Mason — 2009-01-29T17:20:37Z

Abstract In 1900 there were fewer than a dozen Spaniards in Queensland, most of whom were transient labourers from Victoria. By 1975 there were several thousand Spaniards, of which the majority had travelled directly to Queensland to settle permanently. The thesis uses a chronological structure to trace the development of Spanish political and cultural identities in Queensland over the seventy-five year period. Early settlers were strongly influenced by radical anarchism, and were engaged in ideological debates and Queensland industrial disputes that referenced patterns of behaviour throughout the Hispanic world. Later settlers were predominantly Basques, and used political associations and cultural events to project their identity and to engage with Queensland society. Queensland’s Spanish communities were never defined simply in terms of ethnicity, nationality or political persuasion. Their cultural and political identity was the product of dynamic interactions between social narratives and transnational and local spaces. Spanish identities were the result of an ongoing and complex dialogue between experiences in Spain and Queensland, which channelled migrants’ memories and expectations. Spaniards were deeply involved in Queensland politics for the entire period of their settlement. Their engagement involved the application and modification of Spanish models of political and cultural action to the Queensland environment. Memories and behaviours were re-articulated through a dialogue that referenced events in Queensland and Spain, and debated their future implications to the local communities. The thesis does not try to separate migrants’ political and cultural identity. Cultural norms enacted in Queensland provided models to achieve both political and social goals in Australia and Spain. Later migrants used ethnic networks to assert their cultural difference, in processes that often had clear political implications. Queenslanders were tolerant of what were seen as folk cultures, and were rarely attuned to the political discussions that underpinned regional ethnicities. Yet, within the Spanish communities, tensions regarding the valid parameters for regional cultural expression were often foils for broader political debates. Queensland Spaniards’ self-perception, and their negotiation of multiple identities, continued to reference the spaces and imagery of Spain. Yet, these identities were subjective, and the move to Queensland altered their purpose and modes of expression. Queensland Spaniards sought to recreate comparable social networks to those that had sustained their identities prior to emigration, frequently contacting comparable Australian groups that shared similar means of expression. Spaniards did not set old identities aside, but new issues in Spain and Queensland forced a process of clarification and the compartmentalisation of roles. Sharp divisions in Spanish communities’ social memories were accentuated by the regional nature of Queensland settlement, focussing cultural debates on regional norms. The regional nature of Queensland’s Spanish settlement altered the expression of cultural and political identities, but also left them relatively uncontested until the influx of Castilian migrants in the late 1950s. Most Spanish migrants to Australia preferred the southern states of Victoria and New South Wales, where greater stability fostered larger and more cohesively ‘Spanish’ communities. Queensland’s long distances and radical political atmosphere instead facilitated the replication of Spain’s regional characteristics. Industrial tensions aided radicals who were able to find comparable political identities, whilst family networks that referred to spaces in Spain developed sophisticated strategies to accelerate chain migration. The thesis corrects a serious lack of research into Spanish migrants in Australia. The group’s small size has led researchers to favour larger communities, despite the important information offered by the Spanish example. The thesis provides a historical narrative of Spaniards’ experiences in Queensland, but also applies academic debates regarding social memories, and investigates their relationship to cultural and political identities. This includes not only the maintenance of social memories, but also their replication and modification over several generations. The analysis uses awareness of political change in both Queensland and Spain, to investigate migrants’ long-term response to political trauma and changed social circumstance.

Agronomic, physiological and genetic studies on a dwarf mutant of cocoa (Theobroma cacao L.)

2009-06-11T11:29:57Z

Cocoa (Theobroma cacao L.) is an important cash crop in the coastal areas of Papua New Guinea (PNG). In 2000, a mutant cocoa genotype MJ 12-226, with abnormal growth characteristics was identified at the Cocoa and Coconut Institute of PNG. The mutant, found among progenies of the cross Scavina 12 x Nanay 149, was characterized by dwarfing, small and narrow leaves, a small root system and strong branching habit. This study was designed to improve the understanding of the dwarf cocoa mutant and identify its relevance to future cocoa farming. The specific objectives are to investigate the feasibility of using a dwarf mutant of cocoa as a commercial rootstock for various hybrid cocoa clones, to study the genetics of this dwarf mutant and the role of plant hormones in differentiating this mutant from the normal phenotype. This study was carried out at the Cocoa and Coconut Institute of PNG, Rabaul, Papua New Guinea, and at the University of Queensland, Gatton Campus, Australia. The comparative study of mutant and normal cocoa seedlings revealed distinct vegetative differences between the two genotypes at the nursery stage. The largest effects of the mutant genotype are on stem elongation, short internodes, multiple stems, root growth and leaf growth. The agronomic results indicated that the mutant rootstock significantly reduced tree vigour at least in the early years. When used as a rootstock, the mutant had a significant dwarfing effect on scion growth of cocoa clones in the nursery and persisted in the field 12 months after planting. After that, the cocoa clones grafted on mutant rootstock reverted to normal growth. It was postulated that the accumulation of endogenous growth substances and cambial activity between the scion (normal) and the rootstock overcame the dwarfing effect of the mutant genotype. Yield and vegetative data collection from this trial ceased on May 2006 and recommenced in May 2007 to allow trees to recover from heavy canopy pruning due to cocoa pod borer attack. This resulted in one year loss of yield and vegetative data from this experiment. The first two years’ yield data indicated no significant differences between mutant, normal segregants and commercial rootstocks. However, cocoa clones bud grafted on these mutant rootstocks produced significantly greater yield at higher planting density compared with lower densities and this was sustained for two years. However, it might be expected that competition among cocoa trees would increase with increased size of trees, favouring low density planting and reducing the differential performance of the trees under high density planting with time. The major advantages of reducing tree vigour are to improve the harvest index, ease of harvesting, pruning and overall management of the trees. The continuation of this study to collect mature tree yield data (from fifth to eighth years) would confirm these results. This work has also demonstrated for the first time that cocoa clones grafted on mutant rootstock can produce similar yields to clones grafted on normal or commercial rootstocks. Moreover, this study has also established that cocoa clones derived from orthotropic scions can yield the same as plagiotropic scions when grafted on to either mutant or normal rootstocks. Therefore, it is proposed that mutant rootstocks and orthtropic scions should also be considered for future use in cocoa farming. The strong branching habit and dwarfing stature of the mutant suggested that the mutation affects the quantity or the balance of plant growth hormones, or both. The effect of exogenously applied gibberellic acid (GA3) on developmental processes in dwarf mutant and normal cocoa seedlings was studied. Both dwarf mutant and normal one month old cocoa seedlings responded to gibberellic acid (GA3) by accelerated longitudinal growth, especially seedling height. Paclobutrazol (PBZ) applied to normal cocoa seedlings altered the growth so that they almost resembled the mutant phenotype. It was postulated that PBZ prevented GA biosynthesis in the normal cocoa seedlings and therefore decreased bioactive auxin (IAA) which, in turn, then promoted lateral shoot growth; PBZ also slightly retarded plant growth. Synthetic auxin (IBA/NAA) significantly inhibited lateral bud sprouting and growth of intact, decapitated and nodal segments of mutant and normal cocoa seedlings compared with control and those treated with IAA. It appears that the mutant and normal cocoa genotypes have a similar capacity to metabolize IAA and this capacity was much greater than for synthetic auxins. The results suggested that auxin levels in the mutant seedlings were probably limiting, and therefore affected biosynthesis of gibberellic acid thus resulting in the dwarfing characteristics of the mutant cocoa genotype. However, analysis of endogenous IAA and GA1 levels at four months old did not reveal differences between the mutant and normal seedlings. The present genetic studies which included backcrossing, test crossing and selfing of F1 progenies confirmed earlier work on the mutant and showed that the mutant was probably heterozygous (Dd). The allele (DD) in mutant cocoa is probably lethal in nature because the phenotype of the homozygote was not observed amongst the mutant progenies. Mutant segregants were obtained in a 1:1 ratio only when the mutant clone was used as the female; however, when the mutant was used as male, very few mutant segregants were obtained. This suggested selective pollen viability (pollen grains carrying the D allele are nonviable) or an incompatible reaction between pollen tubes (D carrying pollen) and style or ovule. The selfing and test-crosses of F1 progenies resulted in deviation from the expected 3:1 segregation ratio to a 1:1 ratio.

Agronomic, physiological and genetic studies on a dwarf mutant of cocoa (Theobroma cacao L.)

Eremas Tade — 2009-06-11T11:29:57Z

Air-Water Bubbly Flows : Theory and Applications

Chanson, Hubert — 2008-11-21T16:55:08Z

In turbulent water flows, large quantities of air bubbles are entrained at the free-surfaces. Practical applications of gas-liquid bubbly flows are found in Chemical, Civil, Environmental, Mechanical, Mining and Nuclear Engineering. Air-water flows are observed in small-scale as well as large-scale flow situations. Typical examples include thin circular jets used as mixing devices in chemical plants (Qw = 0.001 L/s, diameter = 1 mm) and spillway flows (Qw larger than 10,000 m3/s, flow thickness over 10 m). In each case, however, the interactions between the entrained air bubbles and the turbulence field are significant. The present manuscript regroups a collection of one book and 43 articles on the study of air bubble entrainment in turbulent flows. The work aims to gain a better understanding of the basic mechanisms of gas entrainment and the nteractions between entrained gas bubbles and the turbulence. It has been the purpose of the research work to assess critically the overall state of this field, to present new analysis and experimental results, to compare these with existing data, and to present new compelling conclusions regarding momentum and void fraction development of air-water gas-liquid bubbly flows. The manuscript presents a comprehensive analysis of the air entrainment processes in free-surface turbulent flows. The air-water flows are investigated as homogeneous mixtures with variable density. The variations of fluid density result from the non-uniform air bubble distributions and the turbulent diffusion process. Several types of air-water free-surface flows are studied : plunging jet flows, open channel flows, and turbulent water jets discharging into air.

A Journey to Re-Empowerment: A Phenomenological Description of the Experiences of Male Victims of Crime

Haynes, Jennifer — 2008-11-21T16:36:05Z

There has been, to date, minimal research on the experiences of male victims of crime. The research into gender differences in the experiences of criminal victimization have tended to focus on women leaving the male experience to be extrapolated from that of women. This study uses phenomenology to describe the experiences of men who are criminally victimized. The men described an eight phase process of victimization: What Happened Was, the Emotional Wince, He Stole My Power, Let Me Tell You How It Felt, Coming To An Understanding Of The Crime, Regaining Control, Consciously Taking Back Power and Its Over Now, Its Not Important. The main goal of the men was to reclaim their lost sense of personal empowerment, stolen in the instance of the crime. The men also had a need to talk through the crime and its aftermath. A supportive listener assisted the man through the process to re-empowerment, whilst a non-supportive listener could complicate the criminal experience, invalidate the victim and result in the man either disengaging from the support process or adopting the non-confirmatory reactions of the listener. Thus the listener held considerable power. Recommendations include police in-service training and the increased use of community conferencing. It is particularly recommended that some attention be paid to rehabilitating the term victim given that men do not easily accept the notion of being a victim.

Alcohol consumption in Muslim Arab and Asian samples: a test of the cognitive model

Mrs Tayyiba AlMarri — 2008-09-24T19:42:58Z

All the World's a Stage: Constructing and Performing the Textual Self in Charlotte Brontë's Fiction

Mari Webb — 2009-09-09T14:24:40Z

Charlotte Brontë’s problematising of first-person narrative foregrounds the fluidity of the concept of identity and insists on its constructed nature. Brontë uses specific narrative techniques in The Professor, Jane Eyre and Villette to achieve this foregrounding, which leads to a complex and sophisticated exploration of the individual’s relationship to society, and how this influences the way individuals construct their identity. Each of these novels presents a different example of such self-construction through the characterisation of the first person narrator. Brontë’s questioning of the stability of the self encourages readers to be aware of such constructs. In my first chapter, I look closely at how narrative authority is parcelled out in Brontë’s nineteenth-century society, and what influence the conferring or withholding of such authority has on the construction of a narrative self. The next three chapters are devoted to discussion of specific examples of narrative self-construction in Brontë’s first-person novels, how her protagonists deal with narrative authority, and the difficulties inherent in speaking or writing with such authority for nineteenth-century women in particular. Individuals construct a sense of their self through telling stories. Brontë’s fiction asks the question, if “Literature cannot be the business of a woman’s life” is this tantamount to denying women the right to an arena for the construction of a self at all? What role do readers play in the construction of a narrative self for a writer? In the concluding chapter my aim is to open out my analysis of Brontë’s fiction by examining the idea of narrative as a place more generally for imaginative self-construction. I structure the chapter around J. Hillis Miller’s argument in On Literature that the role of reading and writing in this regard has irrevocably changed in the twenty-first century due to the influence and popularity of the on-line world.

Alternating steering control-response compatibility: Compatibility, age, practice, strategy and instruction effects on performance characteristics of driving a simulated underground coal mine shuttle car.

Christine Zupanc — 2008-10-09T11:30:21Z

A macroscopic chemistry method for the direct simulation of non-equilibrium gas flows

Lilley, Charles Ranald — 2008-11-21T16:54:30Z

The macroscopic chemistry method for modelling non-equilibrium reacting gas flows with the direct simulation Monte Carlo (DSMC) method is developed and tested. In the macroscopic method, the calculation of chemical reactions is decoupled from the DSMC collision routine. The number of reaction events that must be performed in a cell is calculated with macroscopic rate expressions. These expressions use local macroscopic information such as kinetic temperatures and density. The macroscopic method is applied to a symmetrical diatomic gas. For each dissociation event, a single diatom is selected with a probability based on internal energy and is dissociated into two atoms. For each recombination event, two atoms are selected at random and replaced by a single diatom. To account for the dissociation energy, the thermal energies of all particles in the cell are adjusted. The macroscopic method differs from conventional collision-based DSMC chemistry procedures, where reactions are performed as an integral part of the collision routine. The most important advantage offered by the macroscopic method is that it can utilise reaction rates that are any function of the macroscopic flow conditions. It therefore allows DSMC chemistry calculations to be performed using rate expressions for which no conventional chemistry model may exist. Given the accuracy and flexibility of the macroscopic method, it has significant potential for modelling reacting non-equilibrium gas flows. The macroscopic method is tested by performing DSMC calculations and comparing the results to those obtained using conventional DSMC chemistry models and experimental data. The macroscopic method gives density profiles in good agreement with experimental data in the chemical relaxation region downstream of a strong shock. Within the shock where strongly non-equilibrium conditions prevail, the macroscopic method provides good agreement with a conventional chemistry model. For the flow over a blunt axisymmetric cylinder, which also exhibits strongly non-equilibrium conditions, the macroscopic method also gives reasonable agreement with conventional chemistry models. The ability of the macroscopic method to utilise any rate expression is demonstrated by using a two-temperature rate model that accounts for dissociation-vibration coupling effects that are important in non-equilibrium reacting flows. Relative to the case without dissociation-vibration coupling, the macroscopic method with the two-temperature model gives reduced dissociation rates in vibrationally cold flows, as expected. Also, for the blunt cylinder flow, the two-temperature model gives reduced surface heat fluxes, as expected. The macroscopic method is also tested with a number density dependent form of the equilibrium constant. For zero-dimensional chemical relaxation, the resulting relaxation histories are in good agreement with those provided by an exact Runge-Kutta solution of the relaxation behaviour. Reviews of basic DSMC procedures and conventional DSMC chemistry models are also given. A method for obtaining the variable hard sphere parameters for collisions between particles of different species is given. Borgnakke-Larsen schemes for modelling internal energy exchange are examined in detail. Both continuous rotational and quantised vibrational energy modes are considered. Detailed derivations of viscosity and collision rate expressions for the generalised hard sphere model of Hassan and Hash [Phys. Fluids 5, 738 (1993)] and the modified version of Macrossan and Lilley [J. Thermophys. Heat Transfer 17, 289 (2003)] are also given.

Ambient Information Display

Jones, Paul Robert — 2008-11-21T15:38:11Z

Ambient Information Displays provide alternate means of displaying information that does not require the direct attention of the user. As the amount of information that people need to process each day grows, alternative methods of information consumption need to be explored. Ambient Displays provide a way of doing this by exploiting peoples peripheral processing capabilities. Significant previous research has investigated the development of different types of displays and analysed the ways that users interact with these displays. Commercial Ambient Information services in the form of wireless devices driven from central servers are available overseas. Little research however has been performed in the field of reusable frameworks for the display of Ambient Information. This work explores two assertions: Many apparently different Ambient Displays can be characterised in terms of a number of common functional modules. The common modules can be developed and reused to greatly simplify the implementation of later Ambient Displays, without each type of display needing to have the same inputs, outputs, or management methodologies. After a background exploration into devices, software structures and the current stateof- the-art in ambient technologies, an iterative development process is utilised to characterise in detail the components required. These components are to be reusable across multiple displays, so that subsequent implementations can be built more quickly and economically. The completion of the iterative process results in a number of developed components that were reused through each of these example displays. To validate the choice of components, a number of thought-experiment style implementations are conducted, where each potential application is analysed and an implementation utilising the developed components is proposed. The fundamental aspect of the proposed set of components is Scenario Based Information Transformation. The assertion is that displays consist of transformations of data from one form to another; the underlying work performed by any given application can be modelled in terms of a transformation scenario. To support applications based on top of scenarios, the following components are required: - Underlying web framework providing the basic environment in which to develop applications. - Executors application installed on local users machines, performing the actual transformation work in taking data from sources and transforming it for the outputs. - Authentication/Identity Management web application supporting the OpenID protocol, and managing identity information for each user. - Configuration Storage allowing for the separated/private storage of user information. - Scenario Dispatch providing the bridge between web applications and the underlying communication method for executors. Analysis of a range of typical applications shows that using these components, applications that monitor different physical or electronic data sources and produce outputs in many varied forms using a variety of communications technologies can be easily developed. In parallel to the software development, hardware output devices are explored. SunSPOT wireless sensor devices and lost-cost USB connected devices are both investigated, each providing quite different experiences and usage possibilities, and allowing several demonstration applications to be fully implemented and tested. The results of this work confirm that it is possible to share components between ambient displays, and to characterise many different displays in terms of a set of common functional components. Display authors need not build the entire infrastructure for new displays, lowering the cost barrier for the design of new displays, and the introduction of new data sources into an ambient information environment.

Ambushers or Sponsors? An Examination of Sponsorship Linked Advertising.

Sarah Kelly — 2009-07-02T18:02:56Z

This research proposes that a construct called Sponsorship Linked Advertising (SLA) is valuable in understanding how brand and corporate advertising link to sponsorship and event marketing. SLA includes both ads that communicate a link to a sponsored event (tiedness) and those that demonstrate, through their overall design, an event’s motif or theme (themedness). In its themed form, SLA differs from creative advertising by virtue of the fact that creative advertising can exist independent of any sponsorship link, whereas sponsorship linked advertisements intentionally unite a sponsorship and an event either implicitly and/or explicitly. With sponsorship investment estimated to be $45.2 billion worldwide (International Events Group 2009) and leverage advertising (i.e., advertising that is employed to heighten awareness of sponsorships or better articulate sponsor-event links) reflecting a similar amount, empirical examination, validation and implementation guidance of SLA as a leveraging strategy is critical. The unique marketing opportunities associated with popular sporting, charitable and arts events also attract non-sponsoring companies which also seek to affiliate with the event, an activity known as ambushing (McKelvey and Grady 2008). Examination of SLA is therefore important in an increasingly competitive and cluttered global sponsorship arena, in which ambushing is becoming a pervasive practice, attracting considerable attention from event organisers, sponsors and policy makers alike, while also detracting from or diluting intended sponsorship communications. Despite widespread use of SLA, no empirical validation of this strategy has been undertaken to date. The present research addresses this gap. Initially, the SLA construct is defined, categorised, and measured through content analysis, then a series of experimental studies are used to achieve empirical validation of the SLA construct. Streams of sponsorship and advertising effectiveness research, along with theories of associative learning, attribution and persuasion, are used to guide examination of SLA effectiveness in new empirical work. Specifically, a series of experiments are used to examine consumers’ cognitive, affective and behavioural responses to SLA. The first experimental study tests a main effect of ad type as well as interactive effects of tiedness and themedness with sponsorship availability (i.e., knowledge of true sponsor) on outcomes including nature and type of thoughts elicited, ad scepticism and sponsor motive attributions. Findings from this study suggest that SLA exposure induces more positive thoughts, less ad scepticism and more favourable attributions than exposure to Non SLA. These results provide initial evidence that consumers process SLA differently to other ad types and interestingly, may derive enjoyment from, or at least exhibit less ad scepticism towards viewing SLA. Finally, the influence of competitive context on sponsor recall is tested by simulating exposure to ambush and/or SLA ad types following a sponsorship announcement. Findings provide evidence to support a memory interference hypothesis and imply that accuracy of sponsor recall is diminished by presence of an ambush ad, but that this effect is moderated by presence of SLA leveraging a previously announced sponsorship. Taken together, the results of this series of studies provide an empirical measurement of SLA strategy and demonstrate construct validity. Further, interpretation of the results gives rise to specific creative strategies for practical implementation. Ecological validity is built into the design by using real events within ad stimuli and investigating SLA in the competitive context in which it occurs. Hence, the results are said to be generalisable to real-world situations, and the resultant creative strategies are arguably contextually valid. This research contributes to existing marketing and sponsorship literature by proposing and empirically validating a new construct. Theoretically, it examines consumer response to SLA by combining information processing and resistance based perspectives. It extends traditional views of ambushing by offering empirical evidence of the practice being widespread and extending to low level sponsors and event “free riders”. Practical implications of this research extend to advertisers and sponsors faced with the challenge of effectively leveraging huge sponsorship investments and assessing return on such investment. Empirical testing of ambushing effects has important implications for the debate on increased regulatory intervention of such practices, a debate centred upon tension between balancing fair marketing practice with the rights of sponsors and event organisers.

Amino Acid Digestibility and Requirements of Broiler Chickens

Mulyantini Ni Gusti Ayu — 2009-01-30T16:20:57Z

The dietary requirement for protein is actually a requirement for the amino acids contained in the dietary protein. The efficiency of protein utilization depends to a large extent on the amino acid composition of the diet. Although a large volume of published amino acid digestibility values for poultry feedstuffs is available, there are still many gaps in our knowledge on digestibility and utilization of amino acids. The major focus of this thesis was to examine several aspects of amino acid digestibility and utilization in broiler chickens. Initial studies examined the performance of two commercial broiler strains fed diets formulated on total or digestible amino acids. The objective of this study was to determine the individual bird response to 4 different diets formulated on: 1) total amino acids; 2) digestible amino acids (book values)using the same ingredient as diet 1; 3) digestible amino acids values determined on the same ingredients as used in diet 1: and 4) digestible amino acids but formulated commercially. The results show that birds given diets formulated on digestible amino acid basis, grew faster, ate more feed and converted it into body weight more efficiently, and had a higher proportion of body protein (P<0.05) than birds given diet formulated on a total amino acid basis. It was also shown that males broiler were significantly faster growing, consumed more feed and had better feed efficiency than do female broilers. There was also a significant (P<0.05)sex x diet interaction for weight gain. Whilst, males always grew faster than females, the difference was much greater for those given the digestible amino acid formulated diets. The studies reported in Chapters 5 and 6 was conducted to determine the digestible methionine, lysine and threonine requirement of broilers during the starter and finisher periods. The minimum digestible methionine requirements to maximize weight gain for starter was similar with grower. Digestible lysine requirements to maximize weight gain represent a decrease 25%, respectively from starter to grower. The lysine digestible requirement for weight gain decreased from 11.4 g/kg diet (0 to 3 wk) to 8.5 g/kg diet (3 to 6 wk). For threonine, the starter threonine level of 6.5 g/kg resulted in the best responses (P<0.01). The study reported in Chapter 7 was to identify the extent of differences in the nutritional value of sorghum available within Australia, in particular the apparent digestibility of amino acids in sorghum samples based upon digesta samples taken from the lower ileum of the chicken. The results of this study suggest that it is possible to estimate digestible amino acid supply from sorghum from the protein content of the grain. Crude protein content (N x 6.25) of sorghum varied from 80.2 to 117.5 g/kg dry matter. In most Australian cereal based diet lysine is first limiting amino acids. In this experimental diet, methionine is the first limiting amino acid content ranged from 1.06 to 1.42%. It followed by lysine, histidine and glycine, respectively. The cereal-based diets fed to poultry contain substantial quantities of phytin,which is poorly digested by poultry. The poor digestive utilization of phytin-bound P by poultry and its consequences on digestibility of protein and amino acids lead to do some more extensive research in this aspect. In this regard, the effects of enzyme supplementation on apparent ileal amino acid digestibility of cereal were studied in Chapter 8. Supplementing wheat fed to 5-wk-old broilers with xylanase alone or a combination of xylanase and phytase improved the ileal digestibility of amino acids. Although there was improvement in sorghum based diet, phytase and xylanase supplementation had no effect on the avaergae of ileal amino acid digestibility. Overall, the results presented in this thesis demonstrate that formulation of poultry diets on a digestible amino acid basis is superior to formulation of diets on a total amino acid basis. This study suggested that genotype and sex differences in performance and body composition should be taken into account when formulating diets to maximize performance of broiler chickens. Moreover, the requirement of digestible lysine, methionine and threonine for broiler chicken during the starter and finisher periods were obtained in this study.

Analysing the Evolution of International Trade: A Complex Networks Approach

Timothy Kastelle — 2008-07-22T09:34:51Z

Analysis and Architectures for Bang-bang Phase Locked Loops

Mr Michael Chan — 2008-11-06T23:29:38Z