UQ Theses Collection (RHD) - UQ staff and students only - UQ eSpace

A sociocultural study of the emergence of a classroom community of practice

Brown, Raymond A. J. — 2007-08-24T17:45:20Z

A socio-economic evaluation of the supervised cattle distribution program in the Philippines

Duthy, Stephen (Stephen W.) — 2008-12-08T00:00:00Z

A software engineering approach to the integration of computer technology into mathematics education

Pollard, Janelle. — 2012-04-17T00:00:00Z

A spatial and temporal quality equilibrium formulation of production scheduling and allocation in the Australian sugar cane industry.

Ryland, G. J. — 2010-11-09T00:00:00Z

A spatial decision support system for location suitability analysis for sustainable tourism development

Kapantow, Gene Henfried Meyer — 2011-11-15T00:00:00Z

A Spatial Equilibrium Analysis of Policies to Promote the Wood-Processing Industry in Northern Vietnam

Hieu Phan Sy — 2011-08-30T00:00:00Z

The Government of Vietnam (GoV) has planned increased self-sufficiency in terms of the domestic production of wood and wood-processing products. For example, by 2010 the forestry industry could supply approximately enough raw materials for the wood-processing industry, including 100% of raw materials for prop, ship, pulp, paper and engineered-wood products, and 85% of raw materials for domestic furniture production. The domestic production of paper and furniture products with the planned quantities of 1.5 and 2.4 Mt respectively would not only meet the domestic demand but also have an export by 2010. In order to achieve the plan, the GoV has sought to increase the area of planted production forest by the implementation of the Five Million Hectares Program and expand the production capacity of the domestic wood-processing industry. For example, in 1998, 19 new paper factories and 20 engineered-wood enterprises were planned to be built in the whole country during the 2000-10 period. Of these, nine paper enterprises and five engineered-wood enterprises were in northern Vietnam. Similar to many countries, main national objectives were not achieved in Vietnam by 2010. Factors impeding the achievement include distances between the new factories, declining import taxes, low design production capacities of the new factories and high average production costs. This thesis seeks to address these problems by developing a spatial equilibrium model (SEM) and applying this model to analyse policies and explain why the gap between objectives and outcomes has existed, and to draw policy implications on how to increase the probability of achieving planned objectives. The statistical data published about wood and wood-processing products published in Vietnam have not been sufficient to populate the SEM. As a result, a research group including the candidate and his colleagues working at the Statistics and Informatics Centre for Agriculture and Rural Development (ICARD) developed new concepts of wood-processing sub-industry, factory and enterprise and new conversion rates between outputs and inputs, and new conversion rates between measurement units of bundle, stere, m3 and tonne. These new concepts and conversion rates were used to re-classify data published in 2008 to make these data understandable and applicable to the SEM. In addition, the research group also collected external price elasticities to use as proxies to domestic price elasticities. In the literature review, the thesis demonstrates that the SEM with linear supply and demand functions and linear constraints can be solved by linear programming, non-linear programming and mixed complementary programming. Because of its simplicity, linear programming has been used to solve the thesis’ SEM. This SEM is used to evaluate the four policy models of base policy model, planned policy model, implemented policy model and recommended policy model. The base policy model is established to test or validate the reliability of the model written in the software package of the General Algebraic Modeling System (GAMS). The contents of the other three policy models depend on policies and their publication time. Two indicators of average production costs and percentages between supply quantities and design production capacities of the factories are used to examine optimal solutions generated by solving these three policy models. A sensitivity analysis is conducted to check how the optimal solutions are affected if domestic price elasticity levels are equal to or 30% less than or 30% higher than external price elasticities. The SEM for nine products and 29 regions reveals that the supply targets cannot be achieved by 2015 period because planned and implemented policies would force tree growers, owners of paper factories and owners of furniture enterprises to sell their products at unprofitable prices and in unprofitable quantities. For these stakeholders’ activities to be financially sustainable the number of planned new wood-processing factories should be reduced and the design production capacity of each new factory should be increased. For example, planned new small-scale paper factories with design production capacities of less than 300,000 tonnes a year and engineered-wood factories with design production capacities of less than 50,000 tonnes a year should not be built. Closure of existing small-scale paper factories of less than 50,000 tonnes by 2015 should be considered. Consequently, the planned area of planted production forest in northern Vietnam should be less than 900,000 ha, considerably lower than the planned level of about 1.2 million ha by 2015. These conclusions are similar to qualitative opinions asserted by various domestic and international experts, who have argued that there are too many factories planned in Vietnam. The SEM developed and applied in this thesis provides a framework for systematic analysis of policy options for the wood and wood-processing industries and the feasibility of planned production targets.

A Special German Responsibility : The Nazi past and the foreign policy of the German Greens, 1980-2004

Humphreys, Andrea Mara — 2008-11-21T00:00:00Z

This thesis discusses the German Greens debates over the lessons of National Socialism, the Second World War and the Holocaust with regard to five foreign policy issues: the euromissile dispute in the early 1980s, the Israeli-Palestinian conflict from 1980-2004, the 1991 Gulf War, the Yugoslav Wars from 1991-1995, and the 1999 Kosovo War. Published and unpublished contributions to the Green debate on each issue are interpreted in terms of the claims they make concerning the lessons of history, and the pressures influencing these. The prominence of the Nazi past in these debates is shown to be at once a reflection of historys normative value for German foreign policy, its instrumental use in intra- and inter-party disputes, and its central role in Green identity, particularly for the 1968 cohort. This is a history of profound change in the political implications of the Nazi past. Chapter 2 traces the Greens changing perspective on the Israeli-Palestinian conflict: from a primary duty towards the Palestinian victims of oppression, stemming from an interpretation of the Holocaust as a by-product of generic fascism, to an understanding of the Holocaust legacy as entailing, above all, German responsibility for Israel. Chapter 1 shows the Greens rejecting violence in the name of German history during the euromissile dispute, while Chapters 3-5 chart ever-increasing challenges to pacifism and the growing belief during debates over Iraq, Bosnia and Kosovo that military force could, at times, be morally correct. It is argued that these studies reveal growing agreement between the German left and right on the lessons of history for German foreign policy, a pattern of change in Green attitudes to the Holocaust in which universal characteristics were first privileged, then de-emphasised, then reestablished in a different version, and the emergence of an argument for humanitarian military intervention grounded in the particular way the New Left and their political successors in the Greens engaged with the Holocaust. The process of confluence between left and right began with the euromissile dispute, when conservatives articulated policy goals in terms of the Holocaust legacy. This process continued throughout the late 1980s and 1990s, as increasing numbers of (mostly realist) Greens accepted conservative conclusions regarding: the undesirability of a pacifist German Sonderweg (if not a desirable normality); responsibility (as opposed to foreign policy guided by an ethic of conscience); the legitimacy of some uses of force based on the lesson of Munich, as well as the Allies war against Hitler and the need to prevent another Auschwitz; and the occasional moral irresponsibility of pacifism. The analysis highlights the tension between particularity and universality in Green interpretations of the Holocaust, and the associated questions of singularity and comparability. The Holocaust featured in Green anti-nuclear arguments as an example of modernitys destructive rationality and one of many horrors of the 20th century; its victims, alongside victims of these other horrors including the bombing war on German cities served to promote anti-militarism. At the same time, the influence of fascism theory and anti-imperialism on the new Green party ensured that Israel was not initially viewed as a haven for Jews persecuted by Germans, but primarily as a persecutor itself. From the mid-1980s, in response to nationalist universalising claims, Greens focused more on the German particularities of Nazism and the Holocaust. The narrative underscores the importance of acrimonious historical disputes of the 1980s: Heiner Geißlers assertion that the pacifism of the 1930s first made Auschwitz possible, Helmut Kohls notion of the grace of late birth, Bitburg and the Historikerstreit resonated throughout Green debates after the Cold War. In the face of ethnic cleansing in the Balkans in the 1990s, the Holocaust was universalised again as a source of transnational political morality in Green and international debates on genocide. Elements of universality and particularity came to the fore in debates over humanitarian military intervention, as Greens reexamined the antifascist imperative. These struggles over the correct lessons of the past are set against fundamental change in the international system and Green in-fighting, as they wrestled with questions of compromise then with the realities of power as part of the red-green coalition from 1998. Particular attention is paid to the realist factions pursuit of Green acceptance of the core of West German foreign policy: integration into the Western community of nations, including NATO.

Aspects of Management of Subterranean Termites in Queensland

Peters, Brenton Charles — 2008-11-21T00:00:00Z

i ABSTRACT I investigated aspects of the management of subterranean termites in the field by evaluating the protective values of preservative treated softwoods and evaluating the potential of softwoods conditioned by decay fungi or heat to produce termite monitoring and aggregating devices. As part of the investigation, it was necessary to: · develop assay techniques suitable for research into the natural resistance of timbers, the efficacy of wood preservatives and termite biology and foraging behaviour; and quantify variation in termite responses to untreated softwoods in various situations in the field using these techniques. Field bioassays were conducted with two Australian Coptotermes species to determine protection of pine sapwood afforded by borate compounds (Chapter 2). Coptotermes lacteus (Froggatt) was examined in winter and C. acinaciformis (Froggatt) in winter, spring and summer at two localities in Queensland. Hoop-(Araucaria cunninghamii Ait ex D. Don) and slash-pine (Pinus elliottii Engelm.)-sapwood blocks were placed in plastic containers and attached to termite mounds or infested trees. Termite response was determined by mass losses over five weeks and modelled. Coptotermes lacteus was relatively benign in winter and for 1.0 and 2.5% mass losses of hoop-pine sapwood, borate retentions of 0.20 and 0.06% mass/mass (m/m) boric acid equivalent (BAE), respectively, were derived. With C. acinaciformis, for 1.0 and 5.0% mass losses of hoop-pine sapwood, borate retentions ranged from 0.49 and 0.25% BAE, respectively, in winter to 0.76 and 0.47% BAE, respectively, in late summer. For 1.0 and 5.0% mass losses of slash-pine sapwood in summer, borate retentions of 0.58 and 0.14% BAE, respectively, were derived for C. acinaciformis. These results support conclusions from earlier laboratory studies conducted elsewhere. Prevention of damage by field populations of termites was not achieved. Marked intercolony variation in response to borate compounds was demonstrated, highlighting the usefulness of this rapid technique. The need for long-term field exposure trials to calibrate the lunch-box technique and to facilitate technology transfer to industry, is indicated. For comparison, termite response to white cypress (Callitris glaucophylla Thompson and Johnson), a naturally termite resistant timber, is also reported. A field bioassay was conducted to evaluate responses of C. acinaciformis to untreated southern-yellow-pine (Pinus spp.), hoop-pine and slash-pine blocks (Chapter 3). Sapwood blocks were placed in plastic containers and attached to trees infested with the termites during summer. Containers with a test block of each of the timber species were prepared. These and other containers were exposed to termites for 10 weeks. Termite feeding response (voracity) was assessed for all blocks by determining the mass of wood consumed. Termite voracity differed among trees. Variation in termite responses to individual hoop-pine feeder-blocks within a container was appreciable and consistent between containers. Variation in termite responses to the test blocks was appreciable, with hoop pine being significantly more susceptible to termite attack than either slash pine or southern yellow pine. Southern yellow pine is a generic name for five species of pine which are difficult to separate reliably. Therefore, caution should be exercised when using southern yellow pine to ensure that samples are at least from the same species of pine and preferably from the same length of timber. The sensitivity of both the bioassay and the statistical tests was demonstrated. Of particular interest was the similar level of termite response to the test timbers in the two sections of the experiment. The usefulness of feeder-blocks to initiate reliable attack rather than to promote sustained attack, is worth further attention. Sapwood stakes of Australian-grown hoop pine, slash pine, radiata pine and North American-grown southern yellow pine were exposed to subterranean termite attack in an in-ground bioassay (Chapter 4). Stakes in bait containers and bare stakes were attacked by C. acinaciformis and Schedorhinotermes intermedius (Brauer). Susceptibility of these timbers was evaluated with regard to potential for termite monitoring and aggregation. Variation between timbers and difference between termite species are described. The relevance of these data to suppressing foraging populations of subterranean termites, in Australia, using insect growth regulators, is discussed. Four field bioassays were conducted using two species of Australian subterranean termites, C acinaciformis and C. lacteus (Chapter 5). Hoop-pine blocks decayed using 14 fungi for four weeks and for 10 weeks were subsequently conditioned using dry heating, freezing or moist heating, and then exposed to termites. Blocks decayed by Gloeophyllum abietinum [Persoon: Fries] Murrill, Trametes lilacino-gilva (Berkeley) Wright & Deschamps, Schizophyllum commune Fries and Rigidoporus undatus (Persoon) Donk and subsequently oven dried, were attacked the most. Oven drying generally enhanced termite feeding responses in these two field bioassays. In a third bioassay, blocks of five softwood timber species conditioned with two high temperature regimes were exposed to C. acinaciformis. Slash pine was attacked the least. Mean mass losses for hoop pine, Caribbean pine (Pinus caribaea Morelet), radiata pine and the interspecific F1 hybrid between Caribbean and slash pine were not significantly different. For C. lacteus, slash and hoop-pine blocks were attacked the least while radiata pine was attacked the most. Additional heating at 105°C increased the susceptibility of most timber species. Relationships between heating duration and the consumption of hoop-pine-sapwood blocks were determined using results from a fourth bioassay. Heating the timber increased feeding responses for both termite species. The selective and rapid response of the termites highlights the usefulness of this field technique for multiple-choice bioassays. The cyclodiene termiticides were withdrawn from use, in Australia, as from 30 June 1995. Implications for the management of subterranean termites in Queensland are discussed. Community perceptions of the use of chemical pesticides and cost do not favour the widespread use of preservative treated timber in buildings. An integrated pest management approach to termite control is the likely direction for the future in Australia. A range of building techniques, regular inspections, and attention to factors that predispose existing buildings to termite attack can reduce the risk of damage from termites, but do not eliminate that risk. There will be an increased need for reliable preventative and remedial treatments involving bait technology. Much more work is needed on termite biology, foraging behaviour and bait toxicants before a baiting system can be confidently commercialised in Australia. Directions for research in Queensland are discussed.

Aspects of olfaction in the life history of antechinus subtropicus

Aland, Rachel Claire. — 2012-04-27T00:00:00Z

Aspects of quantum phase space

Watson, Philip — 2012-11-01T00:00:00Z

Aspects of Technique in Dvořák’s Cello Concerto: An Approach Based on a Comparative Study of Relevant Treatises

Timothy Byrne — 2010-09-14T00:00:00Z

This commentary examines four specific aspects of technique in Dvořák’s Cello Concerto in B minor which cover a cross-section of the most important technical issues in the work. A comparative analysis of the foremost treatises from the eighteenth to the twentieth centuries forms the basis for this examination, and is used to deconstruct the selected techniques. The commentary thus evaluates the effectiveness and value of a detailed treatise-based approach on the study and performance of advanced cello repertoire. Because the context for this examination was preparation of the writer’s own performance of the work, this examination consists of a synthesis of information from the treatises, along with information based on first-hand observations. This examination reveals how cellists can clarify and simplify their playing by observing the directions and guiding principles in the treatises, incorporating relevant aspects into their own playing or teaching.

Aspects of the biology of Tetranychus urticae (Koch) : with special reference to apples in the Stanthorpe district of Queensland.

Bengston, Mervyn — 2010-09-02T00:00:00Z

Aspects of the nature and characteristics of Monterey pine (P. radiata d. don)

Fielding, John Mervyn. — 2010-11-25T00:00:00Z

Aspects of the population dynamics of ticks infesting cattle in Queensland.

Sutherst, R. W. (Robert W.) — 2012-05-14T00:00:00Z

Aspects of the taxonomy and ecology of the oscillatoriales (Cyanoprokaryota) of north-eastern Australia

McGregor, Glenn B. — 2008-11-21T00:00:00Z

Aspects of wine and drunkenness in late antiquity: changes in a changing world

McTavish, Leigh — 2012-08-02T00:00:00Z

Asperger syndrome and high functioning autism : same, different, or a spectrum? An investigation using a comprehensive communication assessment battery

Fiona M. Lewis — 2008-08-15T00:00:00Z

Assessing and planning for the climate and biodiversity outcomes of avoided deforestation

Oscar Venter — 2011-06-23T00:00:00Z

Tropical forests are the oldest and most ecologically complex of the planet’s terrestrial ecosystems (Myers 1984). Unsustainable logging, conversion to agriculture and anthropogenic fires caused these biological storehouses to shrink by 5-12 million hectares per year since 1980 (DeFries et al. 2002; FAO 2006, 2010). Unchecked, tropical deforestation could be this century’s biggest driver of biodiversity loss (Laurance 2007a; Pimm & Raven 2000; Whitmore & Sayer 1992). Simultaneously, the degradation and conversion of tropical forests is causing 12-25% of anthropogenic carbon emissions (IPCC 2007; van der Werf et al. 2009). In 2005, at the United Nations climate talks in Montreal, the concept of creating a funding mechanism to provide incentives for reducing emissions from deforestation and forest degradation (REDD) was born. Since then, REDD has grown into one of the most widely supported initiatives within UN climate negotiations (UNFCCC 2009). With global carbon markets forecast to trade US$600 billion by 2013 (SBI 2009), REDD is widely viewed as the best chance to secure a future for tropical forests (Laurance 2008). This thesis draws on decision science, first to assess the capacity for REDD to conserve imperilled biodiversity and second to develop approaches for making smart decisions for REDD implementation. Environmentally harmful subsidies are estimated at $1 trillion annually (van Beers & de Moor 1999), forestry exports from developing countries are worth $39 billion annually (FAO 2007) and a single agricultural commodity, palm oil, from a single country, Indonesia, is worth $4 billion annually (FAO 2007). Can REDD really provide incentives great enough to protect forests from such large and profitable industries? In Chapter 2, I use cost-benefit analyses to determine the financial viability of REDD in 808 agricultural leases slated for conversion to industrial oil palm plantations in Kalimantan, Indonesia. I discover that REDD can compete with oil palm plantations if averted carbon emissions are valued at current market prices. The results demonstrate that REDD is a financially viable land use, even when facing an agricultural crop as profitable as palm oil. Without specific provisions for biodiversity, REDD is likely to protect forests that are most cost-effective for reducing carbon emissions. In Chapter 3, I use a dynamic decision science approach to critically assess how well such forest protection will protect biodiversity at the global scale. I demonstrate spatial trade-offs in allocating funds to protect forests for carbon and biodiversity, and show that cost-effective spending for REDD would protect relatively few species. However, because trade-offs are non-linear, I discover that minor adjustments to the allocation of funds could double the biodiversity protected by REDD, with negligible compromise to carbon outcomes. This chapter demonstrates that though REDD might be well funded, it will not be a silver bullet for biodiversity without some extra effort. As REDD scales up from site based projects to larger landscape-scales, and even national scale programs, making smart decisions about which strategies to implement and where to implement them becomes increasingly difficult. In Chapter 4, I present the first spatially explicit approach to prioritize systematically REDD strategies and locations. I discover that if agricultural expansion is prioritized alongside efforts to reduce emissions, land which is slated for conversion to agriculture can play a much larger role in reducing emissions. Moreover, meeting REDD targets becomes cheaper and agricultural production becomes more efficient. I demonstrate that the decision approach is robust to data quality and that efficient outcomes could be expected even in the situation where only freely available data are used. The approach presents a transparent and defensible method for developing cost-efficient solutions for obtaining the targets set forth by large-scale REDD programs. Actors, such as non-governmental organizations, working to conserve imperilled biodiversity have for several decades served as an integral part of the response to the tropical forest crisis. But, with the emergence of REDD, the tropical forest landscape is rapidly changing. How should biodiversity and REDD actors interact? In Chapter 5, I critically assess for the first time the expected outcomes of three contrasting scenarios of engagement between a biodiversity actor and a REDD actor working in the same region. I discover that if a biodiversity actor acts in ignorance of REDD, meeting their targets is substantially more expensive than necessary. Meeting biodiversity and carbon targets is always cheaper if actors collaborate. However, if the REDD actor has a relatively large budget, the biodiversity actor could benefit even more by free-riding off the REDD actor, which involves shifting biodiversity investments to areas not sufficiently represented by the REDD actor’s conservation network. While good for biodiversity, free-riding leads to a conservation network that costs more overall than one selected collaboratively.

ASSESSING ENERGY REQUIREMENTS AND BODY COMPOSITION: IMPLICATIONS FOR CLINICAL PRACTICE

Sarah Elliott — 2012-05-23T00:00:00Z

Paediatric obesity arises as a result of a positive energy balance. A positive energy balance may be due to a reduced energy expenditure or increased energy intake. The reduced energy expenditure is often due to a reduced energy cost of activity, but a reduction in energy expenditure at rest can sometimes occur. In some disease states, such as Duchenne muscular dystrophy, energy imbalance may be a result of a decrease in resting energy expenditure, due to alterations in body composition, or energy metabolism. Regardless of the aetiology, the basis of dietary prescription to create an energy deficit relies on the accurate assessment of energy requirements. The use of the doubly labelled water method to measure total energy expenditure, and in turn, energy requirements, is impractical and costly in a clinical setting. As a result, predictive equations and self-reported measures of physical activity and energy intake, to establish baseline energy requirements, are frequently used. Current equations are based on data obtained from healthy paediatric populations, and the use of such equations to estimate energy requirements in populations whom differ from the norm are yet to be established. Furthermore, the accurate assessment of body composition is vital for evaluating and monitoring the success of various management programmes. While many body composition analysis techniques were developed in healthy adult populations, the use of these techniques in clinical, paediatric populations is questionable. To provide an insight into these issues, this thesis explored the assessment of energy requirements and body composition in two different paediatric cohorts (obese children and adolescents, and ambulatory boys with Duchenne muscular dystrophy). Additionally, the feasibility of a reduced dose of isotopes in the doubly labelled water technique was assessed in a cohort of healthy control children.

Assessing higher order mathematical thinking through applications

Stillman, Gloria (Gloria Ann) — 2007-08-24T17:56:10Z

Assessing institutional progress towards sustainability

Vella, Karen Juanita — 2007-08-24T00:00:00Z

Assessing Self-Reliance in Australian defence and alliance policy, 1966-2006

Lankowski, Michael James — 2008-11-21T00:00:00Z

Assessing the ability of acid sulfate soil laboratory tests to predict environmental risk and lime amelioration

McElnea, Angus Eric — 2007-08-24T00:00:00Z

Assessing the Cost-Effectiveness and Exploring the Implementation of Interventions for Major Depression in Thailand

Benjamas Prukkanone — 2011-10-09T00:00:00Z

Abstract This thesis aims to provide policy makers in Thailand with an evidence base for prioritizing interventions for major depression. The first objective was to determine adherence to antidepressant drugs for the treatment of major depression. The second objective was to identify an optimal set of treatments for major depression in Thailand based on cost-effectiveness analyses (CEA). The final objective was to make recommendations regarding the implementation of the most cost-effective interventions to address major depression in the context of Thailand’s health services. A mixed method research design was used combining quantitative methods to determine adherence and cost-effectiveness with qualitative methods to explore issues around the implementation of cognitive behavioral therapy (CBT), a psychotherapeutic intervention that was found to be cost-effective, if the effectiveness reported in the international literature can be replicated in Thailand. Adherence was only 41% in the cohort of patients attending health services at least twice. If we assume that all patients who attended only once were non-adherent, adherence would have been as low as 23%. A large proportion of cases received more than one drug per visit or was switched from one drug to another (39%). This level of adherence to antidepressant therapy for the treatment of major depression in Thailand is rather low compared to findings from elsewhere. Generic fluoxetine, a selective serotonin re-uptake inhibitor (SSRI), CBT and a screening program in primary care followed by the same treatments were selected for cost-effectiveness analysis. Generic fluoxetine is the cheapest drug option in Thailand and evidence shows no difference in effectiveness between different classes of antidepressant drugs. CBT is the psychotherapy treatment option with the largest evidence base of effectiveness. The cost-effectiveness ratios for treating depression in Thailand with generic fluoxetine or CBT fall below the threshold of 1 times gross domestic product (GDP) per capita (110,000 Baht in Thailand in 2005), the recommended cut-off for an intervention to be considered “very cost-effective”. The uncertainty intervals overlap, meaning that CBT and generic fluoxetine are equally cost-effective treatment options for the treatment of major depression in Thailand. Similarly favorable results were obtained for the cost-effectiveness of using either treatment option during episodes only or as a maintenance treatment variant over a five-year period. The cost-effectiveness ratio s for screening followed by CBT treatment or drug treatment also fell below 1 times GDP per capita. The shortage of mental health personnel, especially psychiatrists and psychologists, who would be expected to deliver treatments for patients with major depression in Thailand, means that policy makers would need to consider the cost of training and expanding the work force. It is estimated that currently less than 5% of people with depression are being treated. While we have identified that a screening program is a cost-effective option to increase case-detection for depression in primary care, its implementation would further increase the workload of already stretched primary care and mental health services in Thailand. Concerned that the favorable results for CBT are largely based on overseas evidence of effectiveness, we conducted in-depth interviews and a focus group discussion with psychiatrists, psychologists, psychiatric nurses, and policy makers in a major psychiatric hospital in central Thailand. Respondents unanimously agreed that there is a need to add more psychological interventions to the current approach that is dominated by a biomedical treatment for depression. Most agreed that with some adjustment for cultural appropriateness, CBT could be acceptable and effective. However, the limited time available to psychiatric health workers and the lack of trained personnel were identified as the main barriers to implementation. There are a lot of strengths worth noting in this thesis. Firstly, where we could, we endeavored to use data from real life settings that are representative of Thailand rather than relying on results from elsewhere. A second strength is that we used a micro-simulation model that helped to capture the heterogeneity in length and frequency of depressive episodes. Another strength is that the efficacy data of antidepressant drugs used for the cost-effectiveness analyses were from a meta-analysis that took into consideration unpublished data from pharmaceutical companies, thus avoiding the publication bias which affects meta-analyses of published trials. However, there are limitations in this research that should be addressed. The first limitation is that there was no information on the effectiveness of the treatment options for major depression in Thailand. We had to rely on information from international meta-analyses. The effect size of these interventions from clinical trials may not directly translate into effectiveness in Thai routine health services, a particular concern for CBT which has not yet been introduced in Thailand apart from small-scale pilot projects. Secondly, the adherence study and the qualitative study were conducted in just one hospital. In addition, the respondent group of the qualitative study was small. For those reasons, these studies should be considered as a first step with further studies required to assess the generalisability of the findings. The last limitation, due to resource limitations of the project, is that we could not assess all possible interventions for the management of major depression in Thailand. For example, future analyses could be extended to include psycho-education, counseling, self-help interventions such as bibliotherapy (self-help books) and internet-based therapy for patients with depression in Thailand. Further qualitative research is also needed to explore the reasons for the low coverage and low adherence to antidepressant therapy in order to formulate interventions to improve the coverage of treatment for depression in Thailand. Concluding remarks: • Generic fluoxetine or CBT is an intervention to be considered “very cost-effective” for treating depression in Thailand. • There is a need to add more psychological interventions to the current treatment for depression, , CBT could be acceptable and effective with some adjustment for cultural appropriateness • However, the limited time available to psychiatric health workers and the lack of trained personnel were identified as the main barriers to implementation CBT in Thailand.

Assessing the Cost-Effectiveness of Interventions for Cardiovascular Disease Prevention in Thailand

Panrasri Khonputsa — 2011-03-22T00:00:00Z

Background: Economic evaluation of interventions for disease prevention and treatment is increasingly popular worldwide due to the need to efficiently allocate limited health care resources. Cardiovascular disease (CVD) is a major health problem in Thailand. Aims: To provide the Thai healthcare system with information on ways to efficiently reduce CVD. Methods: The dissertation is composed of six parts. The first part involves literature search to convey an understanding of CVD epidemiology (incidence, prevalence, and mortality), and health and economic outcomes. General methods for assessing burden of disease and risk factors and economic evaluation are also presented. Although this thesis advocates the use of ‘absolute CVD risk assessment’ in favour of treatment by individual risk factors, the second chapter reports the joint prevalence, treatment and control, and factors associated with diagnosis, treatment and control of hypercholesterolemia and hypertension using data from a national health survey. This was done to gain an overview of both risk factors and their current treatment in Thailand before turning to the absolute risk approach. Chapter Three measures associations, in terms of relative risk (RR), of systolic blood pressure (SBP) and cholesterol (TC) with ischaemic heart disease (IHD) and stroke. RRs of IHD/stroke associated with 10 mmHg increase in SBP or 1 mmol/l increase in TC are assessed for 2,702 males and 797 females aged 35-54 at the start of study using Cox Proportional Hazards Models. The results are compared with those obtained elsewhere. Chapter Four presents the development of a tool for predicting CVD risks for Thai people. Framingham risk equations are recalibrated using contemporary cumulative risks of CVD. Using Thai population data, predictions of the recalibrated equations are compared with those generated with a published equation. Chapter Five assesses the cost-effectiveness of blood pressure (BP) and TC lowering drugs for CVD prevention in 6 population subgroups by sex and level of absolute CVD risk. A Markov model is developed with 4 explicit health states: alive without CVD, alive with IHD, alive with stroke and death. The comparator is doing nothing. Current practice is also assessed. Results: There is clear evidence for a causal link between CVD and several risk factors (such as suboptimal blood pressure (BP) and total cholesterol (TC), tobacco use, and diabetes mellitus), and a number of interventions have been proven effective against CVD. Reduction of TC and/or BP from any level is beneficial in reducing CVD incidence. The terms ‘hypertension’ or ‘hypercholesterolemia’ have become clinically less important than ‘absolute CVD risk’, which takes into account synergistic effects of multiple risk factors. Although the evidence comes mainly from developed countries, there is a trend towards greater risk factor exposure in many developing countries because of changes towards life styles with high fat consumption, low physical activity levels, and low vegetable and fruit consumption. Rises in CVD incidence in developing countries are likely (Chapter 1). In Thailand, 14% and 17% of men and women have hypercholesterolemia, 23% and 21% have hypertension, and 5% and 6% have both, respectively. A large proportion of individuals with these risk factors is not diagnosed nor treated, let alone adequately controlled (Chapter 2). Assessment of associations showed that each 1 mmol/L increase in TC is associated with a 5-fold increase in IHD risk in people aged 30-44. RRs of IHD/stroke per 10 mmHg increase in SBP are significant in all age groups. Increases in IHD and stroke risks associated with these 2 risk factors are comparable to those in the Asia Pacific and western populations (Chapter 3). In Chapter Four, average incidence of IHD in men and women aged 30+ is estimated at 480 and 500, and stroke, 840 and 720 per 100,000, respectively. Framingham equations before calibration overestimated IHD risks by 250% in men and 59% in women and stroke by 16% in men. Our equation produced similar predictions for CVD risks in Thai men over 8 years as the existing equation, but our equations can be used for predicting CVD risk at any time span and in both sexes. Assessment of the cost-effectiveness of BP and TC lowering drugs shows that the most cost-effective option for CVD prevention in people with 10-year risks of 5% and greater would be a generic ‘polypill’ (a theoretical tablet containing three BP lowering drugs (thiazide diuretics, calcium channel blockers, and angiotensin converting enzyme inhibitors) in half standard doses and a statin in standard dose) followed by a combination of the three generic BP drugs (in full doses). Current practice is much less cost-effective than these generic combinations. Conclusions: There is great scope for improved prevention of CVD in Thailand with regards to current levels and management of BP and TC and the use of effective generic drugs. Intensification of these interventions is strongly recommended. Cost-effectiveness of other population wide interventions such as the use of food condiments high in potassium and low in sodium and tobacco use cessation should be further investigated.

Assessing the implications of labour migration for competitiveness - with evidence from Taiwan

Hooper, Karen — 2007-08-24T00:00:00Z

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Mills, David — 2008-11-21T00:00:00Z

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Norris, Michael James. — 2007-08-24T00:00:00Z

Assessment and Treatment of Emotional and Social Understanding Deficits in Children with Asperger Syndrome

Beaumont, Renae — 2008-11-21T00:00:00Z

Assessment and Understanding of Copper Speciation and Phytoavailability/toxicity in Acidic Waters and Soils

Zhi Ling ZENG — 2008-11-24T00:00:00Z

Assessment, development and validation of nitric oxide formation and destruction mechanisms for pulverized coal fired combustion

Williams, Anthony Noel. — 2011-05-06T16:35:57Z

Assessment of Acquired Neurogenic Communication Disorders in Adults using a Telerehabilitation Application

Anne Hill — 2008-11-25T00:00:00Z

Assessment of Cardiac Myxoma Tumour Markers and Development of a Calretinin Grading System.

Indra A. J Nordstrand — 2010-10-13T00:00:00Z

Abstract _____________________________________________________________________ INTRODUCTION Cardiac myxomas represent the most common primary tumour of the heart with a propensity to produce significant morbidity and mortality related to their morphological features and clinical profiles (Terracciano et al 2000; Acebo et al 20011; Shapiro 2001; Keeling et al 2002; Val-Bernal et al 2003). Correct and early diagnosis impacts on outcome by ensuring referral to a tertiary cardiothoracic surgical centre for definitive management – that is, tumour excision (Pinede et al 2001). Embolism is an important subgroup of clinical profiles associated with this tumour. Despite the devastating nature of this presentation, diagnosis is often delayed with an absence of cardiac features pointing toward a cardiac source (Álvarez-Sabín et al 2001). Being able to direct investigation may influence outcome. Whilst the majority of embolic events are to the head, a proportion affects the peripheral circulation (eg. limbs). All material retrieved through embolectomy should be examined histologically for possible tumour embolisation (Hashimoto et al 1999; Shapiro 2001; Val-Bernal et al 2003). Immunohistochemistry (IHC) has transformed the practice of histopathology; informative in diagnosing surgical pathology (Muro-Cacho 1998; Werner et al 2000; Rüdiger et al 2002). Previous IHC analysis of cardiac myxomas has been of little use due to inconsistent results (Burke and Virmani 1996; Basso et al 1998; Chopra et al 1999; Pucci et al 2000; Terracciano et al 2000; Val-Bernal et al 2003). Calretinin (Cal) is a consistent marker identified for cardiac myxomas (Terracciano et al 2000; Acebo et al 20011) with a recognised need for extended validation (Acebo et al 20011). Immunohistochemistry with Cal could provide definitive diagnosis of cardiac myxoma in terms of primary disease and metastatic deposits. This research represents the largest experience investigating Cal IHC in the world. It will attempt to verify previous European studies (Terracciano et al 2000; Acebo et al 20011) and report if such a relation does exist. It also represents the first such examination to be performed outside of large European and American clinical centres. Unlike previous studies, this research also aims to establish a recommendation for routine IHC analysis with Cal of all retrieved embolectomy tissue and excised intracardiac tumour tissue. To assist introduction into the pathology community, a semi-structured grading system for Cal IHC will be developed. Surface thrombus on cardiac myxomas is a feature directly related to embolic clinical profile (Basso et al 1997; Robbin et al 1997; Fernandes et al 2001; Kamiya et al 2001). Currently, the use of antithrombotics in patients with cardiac myxoma is empiric but recommended in high-risk cases. However, routine use of antithrombotics has an identifiable bleeding risk. Therefore, it would be advantageous to target antithrombotic therapy to those who would best benefit while avoiding it in those at low-risk of thromboembolic complications. Thrombomodulin (TM) is an anticoagulant whose expression has been identified on cardiac myxoma surface cells and an active role in protection against thrombus formation has been suggested (Weiler-Guettler et al 1998; Acebo et al 20011; Ashkenas 2001; Isermann et al 2001). This research aims to investigate the thromboprotective role of TM expression in relation to macroscopic surface thrombus or thromboembolic sequelae in patients with cardiac myxoma. It will also be the second series in the world to examine the relation between TM and cardiac myxomas. The hypotheses of this Master of Philosophy research are: 1. That the clinical experience with cardiac myxoma (presentation, management and outcomes) at The Prince Charles Hospital will be comparable to worldwide experience. 2. That a semi-structured grading system for Calretinin IHC in the diagnosis of cardiac myxoma can be developed. 3. That Calretinin is a consistent tissue marker for cardiac myxoma and thus should be recommended for routine immunohistochemical staining to accurately diagnose or exclude this tumour. 4. That Thrombomodulin expression will vary in cardiac myxomas and that: (i) high expression of Thrombomodulin correlates with an absence of macroscopic surface thrombus and low rate of thromboembolic complications (ii) low expression of Thrombomodulin correlates with macroscopic surface thrombus and a higher rate of thromboembolic sequelae. 5. That antithrombotic agents should be prescribed in all patients with cardiac myxoma regardless of presenting features because of the morphological nature of the tumour but especially in those presenting with embolic clinical features of cardiac myxoma or familial disease. The aims of this Master of Philosophy degree are: 1. To retrospectively review the experience with cardiac myxomas at The Prince Charles Hospital assessing clinical presentation and management for comparison with worldwide experience. 2. To develop a semi-structured grading system for examining Calretinin immunohistochemical marking that demonstrates validity and reproducibility of results for introduction into the pathology community. 3. To examine the consistency of Calretinin as a tissue marker in cardiac myxoma and the potential role for routine Calretinin immunohistochemical staining of all excised intracardiac tumour and retrieved embolectomy tissue to accurately confirm or exclude the diagnosis. 4. To identify if Thrombomodulin expression relates to clinicopathological thrombus (cases with documented macroscopic surface thrombus or thromboembolic sequelae) in patients with cardiac myxoma by examining Thrombomodulin expression on cardiac myxoma surface. 5. To examine the use of antithrombotic agents in patients with cardiac myxoma and make a recommendation for their use by examining Thrombomodulin expression on cardiac myxoma surface in relation to the clinical and pathological features of the tumour. METHODOLOGY Subjects with a coded diagnosis of cardiac myxoma, having undergone surgical excision, were identified from The Prince Charles Hospital (TPCH) Cardiac Surgery Research Database (CSRDB) over a 12-year period (January 1992 – December 2003). Appropriate approval from the Cardiac Surgery Research Office Chairman, TPCH Human Research Ethics Committee (HREC) and The University of Queensland HREC was sought and obtained. The medical record of each subject was examined. Patient demographics, clinical presentation, associated cardiac conditions, specific tumour data, echocardiographic and histopathological findings were recorded in addition to surgical technique, follow-up surveillance and use of antithrombotic agents. Detailed analysis of the patients was compared with experience and management worldwide with a specific focus on embolic cases and use of antithrombotic agents both in short and long-term management. Archived cardiac myxoma tissue specimens were retrieved from TPCH Department of Anatomical Pathology for review. Specimens were re-cut in triplicate for immunohistochemical (IHC) analysis. Positive and negative controls were used. Immunoreactivity of the tumours was specifically tested for Cal and TM. RESULTS Thirty patients with a diagnosis of cardiac myxoma were retrieved from TPCH CSRDB, comprising a female:male ratio 2.8:1 with the majority 96.7% adult (≥16-years-of-age). Sporadic disease accounted for 76.7%, nearly six-times more frequent than familial cases at 13.3%; another 10% represented cases suspicious for familial development. A total of 33 tumours were present in the cohort giving an annual incidence of 2.5 cases/year. Preoperative echocardiography was diagnostic in 79.3% with 90% of cardiac myxomas identified as solitary tumours in a single chamber (93.3%) (location ratio LA:RA:biatrial of 13:1:2); synchronous disease (>1 myxoma/patient) was seen in 10%. Intraoperative diagnosis was made in 20.7% of cases. The average time interval from symptom development to diagnosis was 6.4-months with a triad of clinical symptoms: intracardiac obstructive in 72.4%, embolic in 44.8% and constitutional in 34.5%; 18.6% of patients experienced more than one symptom type. Of the embolic subgroup, central embolism occurred more frequently than peripheral embolism with a ratio 2.7:1. With an interval from diagnosis to surgical intervention of 0.9-months, surgical excision of myxoma was performed in all cases with biatrial access employed in 90% either through a right atriotomy, accessing the LA transeptally (quasi-biatrial), or a combination of separate right and left atriotomies (biatrial). An associated cardiac surgical procedure was performed at myxoma operation in 33.3%. Thirty-day postoperative survival was 96.7% with one early death; a second late death occurred at >30-days postoperatively giving an overall cohort survival of 93.3%. Patient follow-up averaged 25 months with 67.9% recommended yearly TTE for life. Tumour recurrence occurred in 3.6% of subjects. In the immediate postoperative period, prophylactic oral anticoagulation was used in 82.8%; the majority 55.2% prescribed aspirin versus 34.5% Warfarin®. Patients discharged home on aspirin were advised lifelong antiplatelet therapy in 61.5%. Patients discharged home on Warfarin® were advised lifelong anticoagulation therapy in 20%. The overall use of antithrombotic agents in cases of embolic clinical presentation of cardiac myxoma was seen in 92.3%. At hospital discharge, 53.8% of the embolic subgroup were taking aspirin and at follow-up, a majority 61.5% from this clinical subset were taking an antithrombotic agent for life versus no prophylaxis in the remaining 38.5%. The major findings from this study, in relation to each aim and hypothesis, were: AIM / HYPOTHESIS 1 • age of patients at diagnosis was significantly younger for familial cardiac myxomas compared with sporadic ones p=0.04 • TTE sensitivity 94%, specificity 21% • TOE lower sensitivity and specificity but positive predictive value 81% • tumours detected by TTE significantly larger than those detected by TOE p<0.0005 • tumour prolapse correlated to the presence of a pedunculated stalk p<0.005 • tumour prolapse correlated to tumour mobility p<0.005 • tumour prolapse did not cause left ventricular outflow obstruction p=0.008 • interval from diagnosis to surgical intervention was shorter than the interval from development of symptoms to diagnosis p<0.05 • embolism relates to gelatinous myxoma feature p=0.06 • embolism relates to pedunculation myxoma feature p=0.02 Non-statistically significant results were found for: 1) relationship between tumour pedunculation and prolapse in tumours with an embolic profile; 2) diagnosis earlier in patients with embolism than non-embolism; 3) advice for life-long aspirin and presence of embolic profiles; 4) embolism relates to friable myxoma feature; 5) embolism relates to fragmentation myxoma feature; 6) embolism relates to prolapse myxoma feature; 7) embolism relates to villous myxoma feature; and 8) embolism relates to surface thrombus myxoma feature. AIM / HYPOTHESIS 2 & 3 • Cal staining sensitivity in cardiac myxomas 96.4% • Cal staining specificity in cardiac myxomas 83.3% • Cal staining is consistent for grade-3 readings p=0.01 • Cal staining is consistent for grade-1 readings p<0.05 • Cal staining is consistent for grade-0 readings p<0.05 • positive Cal staining correlates to cardiac myxoma diagnosis p=0.00012 The use of Cal staining to assist confirmation or exclusion of the diagnosis of cardiac myxoma was demonstrated in this study using a semi-structured grading system specifically designed for this study. Staining for Cal was positive in 93.3% of cardiac myxoma cases. The average frequency of grading was 57% for grade-3, 25% for grade-2, 14% for grade-1 and 4% for grade-0 across five readings. Examination of the Cal slides on five separate occasions assessed the quality of the IHC method and reader-reliability. A non-statistically significant result was found for Cal staining being consistent for grade-2 readings. The second hypothesis of developing a semi-structured grading system for examining Cal IHC in cardiac myxomas was supported by these findings. The semi-structured grading system for Cal demonstrated a high positive Pearson r at greater than 0.80 when comparing each reading with each reader; a perfect linear relationship evidenced on seven occasions. A low instrument error and solid test-retest reliability were demonstrated by a high Pearson r but non-significant difference of paired t-test at the various reading times. Cal staining for cardiac myxomas was highly sensitive being positive when myxoma is present. It was also specific being negative when myxoma is not present. The results were associated with a low false negative and low false positive rate. The high positive predictive value result for Cal staining (96.4%) is high enough for the presence of Cal staining to diagnose cardiac myxoma, supporting its use in diagnostic and management decision making. The strong negative predictive value (83.3%) for Cal staining is also high enough for the absence of Cal staining to exclude a diagnosis of cardiac myxoma. These results overall support the third hypothesis with implementation of Cal IHC into pathology practice. AIM / HYPOTHESIS 4 & 5 A distinct pattern of TM immunostaining was demonstrated in the myxoma specimens. Overall, TM expression was present in 85.7% of cardiac myxomas with tumour stromal cell TM expression demonstrated in 78.6%, and tumour perivascular cell expression in 75%. Surface TM expression was identified in 85.7% of tumours and 71.4% demonstrated tumour cell extension to tumour surface. Through repeated readings, results correlated (p=0.01) to prove interobserver reliability. The importance of TM expression raised in this study relates to the immunostain’s use in providing a diagnostic link for clinicopathological thrombosis (CPT) in patients with cardiac myxoma and the long-term use of antithrombotic agents in the management of cardiac myxomas with recommendations for targeting antithrombotic therapy. However, no statistically significant relation between TM expression and CPT was established. Thrombomodulin expression (surface and tumour cell) was not statistically found to be thromboprotective against clinicopathological thrombosis despite being identified in 62.1% of the cohort. Whilst TM expression did vary in the study cohort, TM expression was more associated with the presence of CPT than the absence; not supporting the fourth hypothesis. No statistically significant relationship between TM expression and low antithrombotic use nor absence of CPT and low antithrombotic use was identified in this study. The majority of antithrombotic agents were prescribed to subjects with TM expression and without evidence of CPT. The fifth hypothesis that patients with high TM expression and low incidence of CPT need less antithrombotic agents was not demonstrated. Overall, no conclusions about the importance of TM expression, CPT and long-term antithrombotic therapy can be drawn. DISCUSSION The findings from this Master of Philosophy research have the potential to impact on the clinical management of cardiac myxomas by pathologists, cardiologists, cardiac surgeons and vascular surgeons. It is the first study in Australia to examine the management of cardiac myxomas in a predominantly adult population at one of the largest cardiothoracic centres in the country, subsequent to the impact of echocardiography in the 1970s on diagnosis. It is the first study performed outside of European and American centres examining the role of IHC in the diagnosis of these tumours. It contains the largest number of cardiac myxomas from a single-unit cohort – that is, 33 tumours in a 30-patient cohort. The importance of such research being carried out in a specialised cardiothoracic, centre such as TPCH is also evident by the fact that more subjects were collected over a shorter period of time than the largest of the European studies – that is, 30 patients over 12-years (incidence of 2.5 cases/year) in this study versus 23 patients over 27-years (incidence of 0.9 cases/year) (Acebo et al 20011). The information contained is unique and educative to cardiac surgery and IHC practice in Australia. Detailed analysis of the patients with this diagnosis is comparable and on par with experience and management worldwide. A semi-structured grading system for Calretinin IHC was successfully developed with consistency, reliability (high interobserver, low instrument error and solid test-retest), validity (content and construct), sensitivity and specificity with high predictive values with the designed semi-structured grading system for Cal. The use of Cal staining to assist confirmation or exclusion of the diagnosis of cardiac myxoma has been demonstrated in this study. Introduction into the pathology community of Cal as a diagnostic tissue marker test should be implemented. The thromboprotective role of TM expression for prevention of surface thrombus in cardiac myxomas has not been demonstrated in this study. The naturally low incidence of cardiac myxoma in the general population would require a much larger number of cases than in this study to be examined for statistical significance to be approached. However, as a secondary benefit, TM expression may aid in confirming cardiac myxoma diagnosis with its distinct pattern of staining despite the immunostain having no significant use as a specific tumour marker in myxomas. RECOMMENDATIONS The results from this study support a recommendation that Cal IHC be performed on all excised intracardiac masses and all retrieved embolectomy tissue. The finding of Cal positive tissue would confirm the diagnosis (provisional or otherwise) in the case of intracardiac mass, and expedite clinical examination for a cardiac myxoma in the case of peripheral embolisation presenting as acute limb ischaemia. In addition, the results support a recommendation that Cal IHC would contribute to more accurate tissue diagnosis in the pathology laboratory as these are rare tumours and individual pathologists will have limited experience in their diagnosis. Benefit also exists in situations where excised intracardiac masses have macroscopically similar appearances. To assist in the implementation of these recommendations, is the introduction into the pathology community of the semi-structured grading system for Cal IHC that was designed and tested in this study. The results from this study demonstrated its consistency, reliability, validity, sensitivity and specificity with high predictive values – all in support of this proposal. This study supports a recommendation that antithrombotic agents should be prescribed for life in all patients presenting with embolic clinical features of cardiac myxoma or familial disease. The antiplatelet agent aspirin would be sufficient. In addition, this study supports a recommendation that antithrombotics should be considered in all patients with cardiac myxoma regardless of presenting features because of the morphological nature of the tumour. These immunohistochemistry and antithrombotic therapy recommendations could impact significantly on the postoperative clinical management of these tumours by cardiologists, cardiac surgeons, vascular surgeons and pathologists. LIMITATIONS The limitations of this study include: 1) retrospective design – reliance on previously collected data allows for variable recording of information and human error in information transfer; 2) cardiac myxoma topic – the uncommon diagnosis means small subject numbers and requires the research to be carried out in a specialised cardiothoracic centre to enhance capture of a continuous patient pool; 3) small and specific subject number – increases the probability of type II errors in the statistical analysis, analogous to a false-negative result but makes calculation of study power difficult; 4) retrospective tissue analysis – potential affect on stored tissue cellularity and antigen avidity for IHC markers in addition to the need for heat-induced epitope-retrieval prior to staining which may reduce epitope concentration after long-periods of storage. AREAS OF FUTURE RESEARCH Future expansion of this study would need prospective design and multicentre involvement. Prospective data collection would reduce the first limitation of variable recording of information in reviewing clinical presentation and management of cardiac myxomas within a cardiothoracic unit and across multiple units. It would also allow for pre-selection of the datasets so that the same information was collected on all subjects. Multicentre involvement would be important to increase subject numbers at a national and international level, incorporating cardiothoracic surgery for cardiac myxoma results and vascular surgery for peripheral embolectomy results. At a national level, a cardiac myxoma registry could be readily established permitting monitoring of tumour development, familial cases as well as obtaining accurate tumour incidence. Employment of the semi-structured grading system for examining Cal immunohistochemistry developed in this study would also allow multicentre data to be collected. The primary centres would be those with cardiothoracic and vascular surgical services, secondary centres those with vascular surgery alone. Using Cal IHC and the grading system to examine all excised intracardiac masses and embolectomy tissue would further test this IHC marker’s consistency on more tissue specimens and the system’s reliability. Increased patient numbers would also support Cal‘s routine use in IHC to confirm or exclude the diagnosis of cardiac myxoma. As a consistent tissue marker in cardiac myxomas, Cal may also be helpful in differentiating the glandular-type of cardiac myxoma as a primary intracardiac tumour from other tumours representing secondary deposits, especially those sharing glandular components (eg. adenocarcinomas). Previous work has not identified IHC markers to enable tissue differentiation (Lindner et al 1999). The potential immunoreactivity of Cal in this sub-group of tumours would require further investigation in a future study. Cal also has a potential role in serum monitoring in cases of cardiac myxoma. A future area of research would be developing a serum assay for Cal. With the establishment of levels of significance, instances of recurrence may be able to be detected before the tumour is of a size large enough for visualisation by echocardiography or of a size large enough to produce clinical symptoms; this would surely impact on patient care. An area that might also warrant further investigation is the relationship between Cal expression by myxomas and development of surface thrombus. As a calcium-binding protein, Cal is thought to be involved in the cellular transport of calcium (Terracciano et al 2000; Val-Bernal et al 2003). Perhaps its dominant expression on these tumours predisposes or is involved in the development of surface thrombus by aiding the coagulation cascade. To identifying if TM expression relates to clinicopathological thrombus and use of antithrombotic agents in cardiac myxoma patients, a future study would again need prospective design and randomisation of antithrombotic therapy to attempt to measure the impact of antithrombotic agents on thrombosis and its relation to TM expression. Multicentre (national and international) cardiothoracic surgery participation would increase capture of cases. Secondarily, TM may also aid in confirming cardiac myxoma diagnosis, with its distinct pattern of staining, despite having no significant use as a specific tumour marker in myxomas; another focus of IHC future study. Intra-arterial thrombolysis in patients with embolic features of cardiac myxoma may offer an option in cases of brain ischaemia / infarction related to this diagnosis. Cases that may be responsive include those with cerebral vessel occlusion by composite tumour and thrombus, surface thrombus or thrombus as a consequence of tumour blockage (Bekavac et al 1997). Whilst only trialled in a single case study (Bekavac et al 1997), further investigation may be warranted. Finally, a future expansion on this study could include tumour gene analysis. With evidence for familial cases linked to an autosomal dominant pattern of inheritance (Shinfeld et al 1998; Chopra et al 1999; Schoen 1999; Morton-Bours et al 2000; Kamiya et al 2001; Vohra et al 2002), a link could positively contribute to myxoma screening in familial cases and definitive identification of familial lineage of disease. Echocardiographic monitoring of these patients and their first-degree relatives would also be more directed. It would also alert the clinician to the potential of these patients having Carney Complex / Carney Syndrome – extracardiac manifestations of cardiac myxoma. CONCLUSIONS This is the first detailed study of cardiac myxomas in a predominantly adult population to be performed at The Prince Charles Hospital (TPCH) and the first detailed study of cardiac myxomas in Australia, with a large single-unit cohort (33 tumours in 30 patients). It is also the first study examining the role of IHC in the diagnosis cardiac myxomas using Cal and TM IHC to be performed outside of large European and American clinical centres. A retrospectively review of the experience with cardiac myxomas at The Prince Charles Hospital was performed assessing clinical presentation and management of cases. This was compared with worldwide experience and found to be on par. Therefore, from the results of this study, the first aim and hypothesis of this Master of Philosophy research has been supported. A semi-structured grading system for examining Cal IHC marking was designed specifically for this study in the absence of any other objective measures in the literature. Four grades (0 to 3) of immunohistochemical staining intensity were determined by microscopic examination. Multiple examinations of the Cal stained cardiac myxoma slides were made. Overall, the semi-structured grading system demonstrated: 1) consistency – the higher the staining grade, the more consistent and less variable were the readings so that at grade-2 and grade-3 there was only an 11% variation across the readings; 2) reliability – Cal-grades recorded at one reading were statistically similar to the grades at another reading (p=0.01) with Pearson r ≥0.80 on all comparisons; 3) validity – the Cal grading is an objective measure for assessing cardiac myxoma tumour markers with published evidence relating Cal to cardiac myxomas; 4) high sensitivity at 96.4% and specificity at 83.3% with a high predictive value of 96.4%. Therefore, from the results of this study, the second aim and hypothesis of this Master of Philosophy research has been supported; the purpose-designed semi-structured grading system for Cal IHC has validity, reliability, repeatability and the characteristics of a diagnostic test such that it could be introduced into the pathology community to guide clinical decision making. The consistency of Cal as a tissue marker in cardiac myxoma was examined. Positive Cal staining was evidenced in 93.3% of the cardiac myxoma specimens in this study. As mentioned above, the high sensitivity and specificity, coupled with a low false negative rate (3.6%) and false positive rate (16.7%), indicates Cal IHC is positive when cardiac myxoma is present and negative when cardiac myxoma is not. The high positive predictive value calculated in this study (96.4%) also supports a diagnosis of cardiac myxoma when Cal IHC is positive. The negative predictive value (83.3%) is sufficiently high enough for an absence of Cal staining to exclude a diagnosis of cardiac myxoma. Therefore, this research has confirmed in a larger cohort than previously published studies, that Cal IHC is a consistent tissue marker in cardiac myxoma and would be able to assist with the diagnosis of cardiac myxoma. Given this consistency, benefit exists in its implementation into pathological practice for all excised intracardiac tumour and retrieved embolectomy tissue; benefit to accurately diagnose rare tissue with which pathology experience may be limited outside of major cardiothoracic centres and where excised intracardiac masses or embolectomy material may have macroscopically similar appearances. A recommendation for examining all retrieved embolectomy tissue in cases of cardiac myxoma already exists in the literature (Val-Bernal et al 2003). This study recommends routine IHC analysis with Cal of all retrieved embolectomy tissue and excised intracardiac tumour tissue to accurately diagnosis or exclude cardiac myxoma, with the added support of the developed semi-structured grading system for Cal IHC. Therefore, from the results of this study, the third aim and hypothesis of this Master of Philosophy research has been supported. TM expression in cardiac myxomas related to CPT (cases with documented macroscopic surface thrombus or thromboembolic sequelae) was examined. TM expression was identified in 85.7% of the overall cohort and in 62.1% of those with CPT. Whilst TM expression was variable it did not demonstrate statistical significance as thromboprotective against CPT. Therefore, from the results of this study, the fourth aim and hypothesis of this Master of Philosophy research has not been supported. Studying this theoretical link is difficult in a retrospective study and with the naturally low incidence of cardiac myxoma in the general population. Antithrombotic agents carry a risk of bleeding complications related to therapy. Currently, the use of antithrombotics in patients with cardiac myxoma is empiric but recommended in high-risk cases. Therefore, an ability to target antithrombotic therapy to a sub-group would be advantageous in reducing both the risk of thromboembolic events and bleeding complications related to their ingestion. The use of antithrombotic agents in patients with cardiac myxoma was examined. In 82.8% of patients, aspirin was prescribed in preference to warfarin. Approximately 60% were advised aspirin for life in the general cohort and in those with embolic clinical features. However, no statistically significant relationship between TM expression and low antithrombotic use nor absence of CPT and low antithrombotic use was identified in this study. The majority of antithrombotic agents were prescribed to subjects with TM expression and without evidence of CPT. Therefore, from the results of this study, the fifth aim and hypothesis of this Master of Philosophy research has not been supported. No conclusions about the importance of TM expression, CPT and long-term antithrombotic therapy can be drawn from the results of this research. A recommendation for anticoagulant/antiplatelet therapy can only be drawn from the published literature (Kapral and Silver 1999; Álvarez-Sabín et al 2001; Bienfait and Moll 2001). Based on these, this research recommends that following surgical excision of cardiac myxomas, patients should be prescribed an antithrombotic agent with the added recommendation of continuing on low-dose aspirin for life; an alternative being clopidogrel. The beneficiaries of such practice would be diverse and include instances of: 1) embolism/embolic complications; 2) recurrence; 3) multiple embolic events before diagnosis; 4) younger patients; 5) female patients; 6) familial cases of development; 7) biatrial tumours; and 8) multicentric tumours (synchronous or metachronous).

Assessment of Fucoidin efficacy in Aβ-peptide induced Alzheimer’s disease rodent model

Aarti Patel — 2009-05-27T00:00:00Z

Abstract Alzheimer’s disease (AD) is a major public health concern worldwide, with an increasing prevalence in the elderly population. AD is a progressive neurological disorder of multi-faceted origin, where factors such as genetic mutations, biochemical changes, along with inflammatory cascade and soluble beta amyloid (Aβ) peptide, are thought to play a pivotal role in synaptic failure and neuronal death, ultimately leading to cognitive and neuropsychiatric decline in patients suffering from the disease. At present, there is no long-term cure for the disease, although there is access to pharmacotherapy that might improve cognitive and neuropsychiatric symptoms early in the course of the disease. The current pharmacological therapy for AD only provides symptomatic relief for a very short period of time. It is therefore of utmost importance to discover other pharmacological strategies that might delay the development of AD and slow down the disease progression in terms of cognitive decline and neurodegeneration. Elucidating the pathogenic mechanisms involved in AD neuropathogenesis is a major goal to find efficacious disease-modifying treatments. What remains to be understood completely are the intracellular pathways affected by Aβ protein which may lead to neurodegeneration in AD. Since phosphorylation and dephosphorylation mechanisms are crucial in the β-amyloid precursor protein (APP) metabolism, protein kinase C has emerged as one of the key regulators of the APP metabolism. Indeed, dysregulation of the PKC pathway might play a role in the intracellular mechanisms of neurodegeneration, but their effective involvement still remains elusive. Therefore, a detailed analysis of PKC pathways in established models of AD neurodegeneration is necessary and will form part of this work. Fucoidin is a sulphated polysaccharide extracted from edible brown seaweed, which has been shown to exhibit anti-inflammatory and anti-oxidant effects as well as being a neuroprotectant in various inflammatory diseases including hypoxic ischemia, atherosclerosis and Heyman nephritis. Therefore, fucoidin may have an inhibitory effect on the inflammatory mechanisms of AD. Little is known, however, about the effect of fucoidin on AD. Animal models of AD are extremely valuable for the discovery and development of new treatments. Rodents have been one of the preferred models for pharmacological and behavioural studies in AD. In this thesis, first aim was to establish a non-transgenic Aβ-induced AD model in rats. AD was induced utilising a published protocol which involved the bilateral injection of aggregated Aβ (1-42) into the CA3 subfield of the hippocampus in rat brain. Behavioural assessment with well defined tools such as the Morris water maze and T-maze were utilised to assess the impairment in spatial working memory in rats. Behavioural impairments along with increased astrocytosis and microgliosis were observed in this particular Aβ-induced AD model. In the established disease model, fucoidin (50 mg/kg/day and 25 mg/kg/day) and ibuprofen (50 mg/kg/day) were shown to provide a partial protective effect on impairment in memory function in the MWM behavioural task in rats treated prior to disease initiation and throughout the course of the study. In addition, the histopathological and quantitative analysis of AD brain sections showed a marked reduction in reactive glial fibrillary acidic protein (GFAP) and microglia in fucoidin (low and high dose) and ibuprofen treated Aβ injected rats compared to untreated Aβ injected rats. These results indicate that fucoidin may serve as a possible effective therapeutic approach to improve AD symptoms. There is strong evidence that PKC α and ε signalling pathways regulate important molecular events in memory impairment and neurodegenerative pathophysiology in AD. A possible neuroprotective mechanism of fucoidin involving attenuation of an Aβ-induced decrease in PKC ε phosphorylation using cultured SHSY5Y neuroblastoma cells as a model system was examined. Co-administration of fucoidin (2μM and 5 μM) with Aβ (1μM) abolished the inhibitory effect of Aβ on the phosphorylation of PKCε in a concentration-dependent manner as revealed by western blot analysis. These findings suggest that a possible mechanism underpinning the neuroprotective effect of fucoidin may be through prevention of A-induced inhibition of PKC phosphorylation and may serve as a possible therapeutic approach to improve AD symptoms. As cellular events that involve PKC are affected by Aβ in in vitro systems, it was necessary to examine whether PKC activity is also modulated by the Aβ treatment in vivo in our Aβ-peptide induced AD model. Therefore, the next aim was to assess the potential for fucoidin use as an intervention therapy in an established disease stage in the Aβ-peptide induced AD model. Intervention with fucoidin (50 mg/kg/day, i.p.) in the established disease stage partially prevented Aβ (1-42) mediated damage with respect to memory impairment, neuroinflammation and PKC ε phosphorylation in the in vivo AD model consistent with the in vitro findings in SHSY5Y cells.

Assessment of Lifestyle and Metabolic Factors in Renal Transplant Recipients

Linda Orazio — 2009-05-21T00:00:00Z

ABSTRACT Introduction: Renal transplant recipients (RTR) with abnormal glucose tolerance (AGT) are at an increased risk of graft failure and cardiovascular disease (CVD). CVD is the major cause of death in RTR. Whilst there are numerous known risk factors for AGT in RTR, it is unknown whether lifestyle factors are found in the presence or play a role in the development of AGT in RTR. The nutritional status of RTR in an Australian population has also not been extensively investigated. Investigation into these areas could help identify modifiable areas for change in the RTR population. Multidisciplinary lifestyle modification, including diet and physical activity (PA) advice from a dietitian, may help reduce modifiable risk factors for CVD in RTR with AGT. Aims: The principle aims of this thesis are to; 1) assess the incidence of obesity and central obesity in RTR and compare to rates in the general Australian population, 2) investigate and compare modifiable lifestyle factors and adipokine levels in RTR with AGT and normal glucose tolerance (NGT) and 3) investigate the effect of a multidisciplinary lifestyle intervention (including dietetic advice) on modifiable CVD risk factors in RTR with AGT. Methods: Chapter 1 presents a review of the literature describing the main nutritional challenges in RTR, cardiovascular risk factors in RTR including adipokine profiles and the role of body composition, diet and PA in RTR. Chapter 2 details the clinical, biochemical, nutritional, body composition, PA and statistical methodologies used in this thesis. In Chapter 3 a descriptive analysis of the anthropometry and cardiovascular risk profile of RTR in an Australian setting is investigated. Chapter 4 investigates the nutritional status of RTR with NGT and AGT in more detail, assessing diet, PA, adipokines and body composition. In Chapter 5, the current literature on lifestyle intervention management (including nutritional management) for obesity and type 2 diabetes mellitus in the general population is discussed. Building on previous chapters, Chapter 6 investigates the effect of a multi-disciplinary lifestyle intervention (with dietetic input) on modifiable cardiovascular risk factors in RTR with AGT. Results: In Chapter 3 it was found that RTR are significantly more centrally obese than those in the general population, and this was particularly the case in younger RTR. Central obesity was associated with CVD risk factors in RTR. Chapter 4 found that a lower level of PA, obesity and central obesity are associated with AGT in RTR, whereas no difference in adipokines or dietary intake was found. In Chapter 6, multidisciplinary lifestyle intervention with dietetic input was found to improve certain risk factors for CVD in RTR with AGT, such as dietary factors (total fat and saturated fat intake) and lipid levels. Conclusions: Central obesity is a common problem in RTR, particularly in those with AGT. Higher levels of PA are associated with lower risk of AGT in RTR, and may help reduce the incidence of central obesity in RTR. Multidisciplinary lifestyle intervention, with dietetic input, can improve some modifiable CVD risk factors in RTR with AGT, however more intensive intervention is required to significantly reduce the incidence of obesity. Key Words: Renal Transplant; Abnormal Glucose Tolerance, Obesity; Cardiovascular Disease; Physical Activity Australian and New Zealand Standard Research Classifications (ANZSRC) 1111 Nutrition and Dietetics, 1102 Cardiovascular medicine and Haematology, 1199 Other Medicine and Health Sciences

ASSESSMENT OF LOCATIONAL MARGINAL PRICE SCHEMES FOR TRANSMISSION CONGESTION MANAGEMENT IN A DEREGULATED POWER SYSTEM

Muhammad Bachtiar Nappu — 2009-10-06T00:00:00Z

The growth of electricity markets around the world has introduced new challenges in which one of the challenges is the uncertainty that has become a structural element in this new environment. Market players have to deal with it to guarantee the appropriate power system planning and operation as well as its own economical liquidity. Under an open access environment in a deregulated power system, transmission management holds a vital role in supporting transactions between suppliers and customers. Nevertheless, a transmission network has some constraints that should be addressed in order to ensure sufficient control to maintain the security level of a power system while maximizing market efficiency. The most obvious drawback of transmission constraints is a congestion problem that becomes an obstacle of perfect competition among the market participants since it can influence spot market pricing. The system becomes congested when the supplier and customer agree to produce and consume a particular amount of electric power, but this can cause the transmission network to exceed its thermal limits. Congestion can cause the market players to exercise market power that can result in price volatility beyond the marginal costs. Thus, it is important to manage congestion efficiently in the design of a power market. One mechanism that has direct correlation with transmission management is market clearing price (MCP). Under an open access environment, energy prices throughout the network will be different and measured based on transmission constraint and network losses. When network losses are ignored and there is no congestion on the transmission lines, the power price will be the same at all nodes. This is known as uniform marginal pricing (UMP). However, as the power flow violates transmission constraints, redispatching generating units is required and this will cause the price at every node to vary. This phenomenon is defined as locational marginal pricing (LMP). Therefore, the market clearing price has a strong relationship with transmission management, which is needed to be assessed in order to obtain an efficient and transparent price but satisfying all market participants. This project investigates an alternative solution to the dispatch mechanism, and then formulates a new Locational Marginal Price scheme using optimization technique that may well control congestion as the main issue. The model will vary and be improved, to be distilled into energy price, congestion revenue, cost of losses, as well as transmission usage tariff. The objective of the project is to support developing standard market design (SMD) in managing transmission systems which promotes economic efficiency, lowers delivered energy costs, maintains power system reliability and mitigates exercising market power.

Assessment of the extent of degradation of electrical insulation in aged power transformers

Saha, Tapan Kumar — 2012-11-20T09:48:30Z

Assessment of the impact of Mikania micrantha Kunth. ex. H.B.K. on crop production systems in Viti Levu Fiji

Apaitia Ravaga Macanawai — 2011-12-08T00:00:00Z

Mikania micrantha Kunth. ex. H.B.K (here after, mikania) is an alien invasive plant species in the Asia and Pacific region and is currently one of the major weeds of plantation crops and home gardens in this region. The purpose of this research project was to assess the current and potential impacts of mikania on crop production systems in Viti Levu, Fiji. To help such an assessment, the distribution and infestation density were assessed, as were aspects of its asexual and sexual reproductive biology, the germination and establishment requirements of its seeds and the soil seed bank dynamics of the weed were investigated. In addition, farmers’ views on its management and potential losses caused by mikania were also assessed. The distribution survey demonstrated that mikania is widespread in Viti Levu and is to be found in 18 other islands in Fiji. It was revealed that mikania was the most frequently occurring weed species on the edges of Saccharum officinarum L. (sugarcane) fields. Mikania was ranked the second most frequently occurring weed in traditional Colocasia esculenta (L.) Schott (taro) production systems in Tailevu and in Naitasiri and was also the most frequently occurring weed in Musa spp. (banana) plots in the two provinces. It was found that 96, 95 and 89% of the weeds found in sugarcane, taro and banana crops respectively were introduced species. A study on the growth potential of the vegetative stem sections of mikania revealed that long stem sections (≥ two nodes) had a greater chance of survival than shorter stem sections. Mature mikania stem sections (with nodes) had a greater chance of survival than young stem sections when buried horizontally or vertically with a node exposed. The growth capacity at the edges and within the central area of a Manihot esculenta Crantz (cassava) and a taro crop showed mikania to grow aggressively at the edges, however to a lesser extent in between the rows of the crops. The lower soil nutrients and light intensity levels within the crop may have played a role in this behaviour. A study on the sexual reproductive capacity of mikania revealed that the flowering season in Viti Levu occurs between April to October coinciding with the cool, drier period of the year which presumably favours insect pollination. It was found that Apis mellifera L. (the honey bee) was the most frequent insect floral visitor. The number of seed produced in each flower head (capitulum), ranged from one to seven with the highest proportion of capitula (95%) carrying four seeds. The number of viable seed produced per m2 was determined to be 90,825 and 98,134 for the high and the moderate rainfall regions, respectively. When determining the conditions for germination, it was found that the optimum constant temperature was in the range of 14 to 29°C, with between 87 to 94% of the seed germinating in this temperature range. Under alternating temperature regimes, mikania seed germination was best at 30/20°C (96.9%) and possessed no primary dormancy. It was observed that c. 50% more mikania seed germinated in a salt solution (150 mM) than did Bidens pilosa L. or Synedrella nodiflora (L.) Gaertn.) seeds indicating a moderate tolerance to germination inhibition in saline soils. There was a greater species richness in the soil seed bank in the high than moderate rainfall region suggesting that rainfall had a role to play in this variation. Sixty percent of the germinable mikania seed emerged more rapidly (within the first 8 days of imbibitions) than A. conyzoides and Ludwigia spp. There were greater numbers of germinable mikania seed and a greater species richness in the traditional, as compared to the mechanised taro plots, indicating that mikania was effectively controlled in the mechanised cropping system. Seed longevity studies demonstrated that seed could live for at least 3 years in the soil seed bank and this was seen for three contrasting collection environments. Finally, the questionnaire and the interview survey indicated that mikania had been present in the root crop and sugarcane farming systems for between 20 to 50 years. Chemical control was the most frequently used method for controlling mikania and farmers controlled the weed to prevent crop losses. Farmers did not control mikania in the non-production areas mainly because they considered this to be a waste of their time and money. Beneficial aspects of mikania mentioned by farmers included the improvement of soil fertility, use as a traditional medicine, use as a livestock feed and as a ground cover. The presence of mikania has caused losses of c. AUD $0.21 million for root crop production and for sugarcane production c. AUD $0.99 to 2.10 million. The findings of this research and its implications on mikania management justify the need to formulate a cost-effective and sustainable management of the weed in Fiji.

Assessment of the physical fertility of bauxite residue with different textural and structural conditions

Buchanan, Simon James — 2008-11-21T00:00:00Z

Bauxite mining and alumina processing in Gove, northern Australia, produces residues that contain significant quantities of sodium hydroxide, sodium carbonate, and sodium aluminate, making the material highly alkaline, saline, and sodic. In an untreated condition these residues are incapable of supporting plant growth, and if left exposed and unstabilised they are highly susceptible to wind and water erosion, presenting a hazard to both man and the environment. Covering these wastes, preferably with vegetation that is native to the area, is therefore considered desirable. The current method of dry stacking bauxite residue necessitates separation into fine grained red mud (RM) and coarse grained residue sand (RS). Adverse chemical properties of RM inhibit plant growth, but moderately successful plant growth has been obtained in ameliorated (seawater neutralised/freshwater leached) RS, where the limitations are largely associated with water stress during the post-monsoon dry season. The water storage capacity of RS can be improved by increasing its fines content, but this can have a detrimental impact on other physical properties of the bauxite residue that are important for vegetative growth. This project aims to determine what effect increasing the fines content of RS has on the physical properties of bauxite residues, by assessing the suitability of various mixtures of RS and RM for supporting plant growth. Two distinctly different textured bauxite residues dominated by silt (RMsilt) and clay (RMclay) particles, were separated from RM by sedimentation and then ameliorated to reduce pH 1:5 to 8.8, electrical conductivity 1:5 < 412 µScm-1, and Na + < 28 cmolckg-1. The RMsilt and RMclay materials were then added to RS at different ratios to create a range of clay (RS/RMclay) dominated mixtures; silt (RS/RMsilt) dominated mixtures; plus an equivalently textured RM. The effect of texture and structure on plant available water capacity (PAWC), saturated hydraulic conductivity (Ksat), and penetration resistance (Pr) was assessed. Structure of puddled mixtures was altered using both crushing (< 2 mm) to simulate thorough tillage, and wetting and drying cycles for consolidation. The PAWC of bauxite residue was not significantly improved until fines content (silt + clay) was increased from 6 % in RS, to 39 % and 62 % in the RS/RMclay and RS/RMsilt mixtures respectively. Increasing the fines content of RS altered the void ratios of the mixtures, changing the pore size distribution from being dominated by large micro-pores in coarse mixtures to be dominated by smaller micro-pores in finer mixtures, which resulted in negligible change in PAWC of coarser textures. Crushing and consolidation increased water storage at potentials of -0.1 to -10 kPa, with negligible effect on PAWC and water storage at lower water potentials. The PAWC of puddled RM was not greater than that of RS, but in crushed RM the PAWC was twice that of RS. The Ksat of mixtures tended to decrease as fines content increased, but increased with level of disturbance. In puddled mixtures Ksat was lowest (mean 0.52 mmh-1) and whilst not shown to be significant, Ksat seemed to be closely associated to packing density and void characteristics of the mixtures. Subjecting puddled materials to successive weathering cycles caused the samples to expand and crack increasing the Ksat of over half the textures by more than an order of magnitude. Crushing increased Ksat of all samples as water movement was no longer restricted to smaller inter-particle voids, but instead capable of moving through larger cracks and around secondary particles and aggregates. Wetting and drying of these crushed samples caused consolidation of particles, reducing Ksat due to the increased tortuousity. A quantitative measure of Ksat after wetting and drying cycles was not able to be attained in these experiments due to insufficient sample size. In puddled mixtures the penetrability at field capacity and wilting point was affected by packing of particles, wherein Pr increased with decreasing void ratio. Increasing the fines content of RS by only a small amount (13-15 %) resulted in a more than 6 fold increase in Pr of puddled mixtures. The Pr of all puddled mixtures other than RS was much higher than the penetrability considered highly restrictive to root elongation (2.0 MPa). This was substantially lower (up to 96%) in the crushed treatments, regardless of texture, and considered favorable to root growth, which suggests that a vital criterion for successful vegetation growth in neutralised bauxite residues is the breaking up of the massive structure. This work concluded that through drying and crushing is a prerequisite for plant growth in bauxite residues and that improvements in soil water availability are only identifiable in the RS when the fines content is increased substantially. To achieve successful plant establishment and sustainable vegetation cover it is recommended that deep ripping and thorough cultivation of puddled bauxite residues be carried out initially prior to propagation in order to improve water infiltration, reduce erodability, and facilitate root elongation.

Assessment of the seasonal changes in the germinable soil seed banks of grazed native pastures in southeast Queensland and their relationship to vegetation dynamics

Saeli, Inambao — 2007-08-24T18:50:14Z

Assessment of the welfare of the captive Asian elephants (Elephas maximus)

Gurusamy, Vivek — 2013-03-11T09:32:05Z

Asset revaluations and debt contracting

Cotter, Julie — 2008-11-21T00:00:00Z

The research question investigated is Do managers of Australian firms use upward asset revaluations to reduce debt contracting costs? Much work in the accounting choice literature is premised on a relation between debt contracts and accounting policies. In particular, prior research using sample periods from the 1970s and early 1980s, provides evidence that asset revaluations are used to reduce the costs of debt contracting (see Whittred and Chan, 1992; Brown, Izan and Loh, 1992; and Cotter and Zimmer, 1995). However, considerable changes to the institutional setting have occurred in the past decade. These institutional changes include increased regulation of asset revaluations and disclosures, changes in the macroeconomic environment, and changes in the Australian debt market. Particularly, there has been a shift in emphasis from public to private debt. The relationship between asset revaluations and debt contracting is examined in the current setting. Following Watts and Zimmermans (1990) suggestion that research into the relationship between firms contracts and their accounting policy choices will be improved by the use of more refined measures of contracting variables, the research commences with an investigation of the terms contained in recently issued debt contracts. Accordingly, this thesis contains two phases. Part A comprises an investigation of the covenants and accounting measurement rules typically contained in the recent debt contracts of listed Australian firms, with an emphasis on the role of asset revaluations. Part B then uses the outcomes of this investigation to determine the refined measures of debt contract terms used in testing hypotheses about the current relationship between asset revaluations and debt contracting. Part A establishes the current dominance of bank loan financing, along with a dramatic decline in the use of public debt. Details of the terms typically contained in bank loan agreements, particularly those relating to asset revaluations, are then investigated using a questionnaire survey of senior corporate bankers and analysis of a small sample of actual contracts. Outstanding public debt contracts are also analysed and compared with private debt contracts. The results of this phase of the research indicate that leverage covenants are the most widely used accounting based covenant in the bank loan agreements of listed Australian firms. In addition, interest coverage, current, tangible net worth, and prior charges ratios are all frequently used. Covenants tend to be less restrictive for larger firms than for smaller firms, and more restrictive for mineral producers than for industrial firms. Covenants contained in bank loan agreements tend to be more restrictive than those contained in convertible note trust deeds. In addition to providing important data for part B, the results of this phase of the research address an important gap in our knowledge about the terms contained in recently issued public and private debt contracts of listed Australian firms. Part B develops hypotheses based on the assumption that the costs of revaluing will be incurred when they are expected to be less than reductions in the costs of debt contracting derived from the revaluation. Due consideration is given to the likelihood that at least some of these costs have changed since prior research was conducted. In addition to the arguments presented in prior asset revaluations research, the expected costs of default on debt contracts, and the accounting discretion available to managers, are investigated as determinants of asset revaluation accounting choices. Predictions are made in relation to the likelihood of revaluation, the choice of valuer type, and whether to recognise or merely disclose new valuations of land and buildings. Interestingly, the results of prior research do not replicate in the current setting. Further analysis shows that differences in results are not due to differences in research methods between the current and prior research. In order to further examine the potential impact of changes to the institutional setting, a series of interviews with Chief Financial Officers is undertaken. The conclusion drawn from this additional analysis is that the relatively closer relationship between firms and their bankers has caused many firms to choose footnote disclosure of undervalued assets in preference to recognising an upward asset revaluation in the balance sheet. Overall, the results indicate that, when investigating the relationship between firms contracts and their accounting policy choices, a consideration of the way that contracts are negotiated and monitored is potentially more important than the use of refined measures of contract terms.

Asset revaluations and share price behaviour in Australia

McMillan, Marion Jean. — 2010-11-10T00:00:00Z

Associated risk factors in developing cervical cancer among Vietnamese women

Mai, Hoang Tran. — 2012-01-06T00:00:00Z

ASSOCIATION BETWEEN HUMAN PAPILLOMAVIRUS, SOLAR KERATOSES AND SQUAMOUS CELL CARCINOMA OF THE SKIN

Hall, Lisa — 2008-11-21T00:00:00Z

Background: Squamous cell carcinoma (SCC) of the skin is one of the most common cancers in white-skinned populations world-wide. Solar keratoses (SK) are benign actinic skin tumours that are strongly associated with SCC and are thought to be precursor lesions. The main causal risk factor for both SK and SCC is ultraviolet radiation. Some researchers propose that there may be a role for HPV in skin carcinogenesis. Evidence is emerging from molecular, immunological and epidemiological studies, but to date is not conclusive. The main purpose of this thesis was to investigate the association between epidermodysplasia verruciformis associated human papillomavirus types (EV-HPV) and two types of actinic skin lesions; solar keratoses (SK) and squamous cell carcinoma (SCC). Methods: Two parallel case control studies were designed to examine SK and SCC respectively. Cases for both studies were recruited from a large public hospital and community-based skin cancer clinics in Brisbane, Australia. Hospital-based controls were recruited from general medical and ophthalmology outpatient clinics. Controls were age- and sex-matched to cases. The SK study involved 126 cases with prevalent SK and 58 controls. The SCC study involved 64 cases with incident SCC and 65 controls. Epidemiological data on a variety of risk factors was collected by the investigator at the patients study appointment and through the use of a self-completed questionnaire. Serum samples, normal skin biopsies and plucked eyebrow hair samples were collected from participants using standard sterile techniques. Where possible a sample of the SCC from SCC cases was also collected during surgery. Fresh tissue samples and eyebrow hairs were snap frozen using liquid nitrogen before being stored at -70°C. DNA extracted from eyebrow and skin samples was amplified and tested for EV-HPV types 5, 8, 15, 20, 24, 36 and 38 using type-specific Polymerase Chain Reaction (PCR) primers. Serum samples were tested for antibodies against the L1 proteins of EV-HPV types 8, 15, 20, 24 and 38 using virus-like particle enzyme-linked immunosorbent assays (VLP-ELISA). Results: A case-control analysis was performed to examine risk factors for SK and SCC such as pigmentary characteristics and UV exposure, independently of HPV status. Country of birth, propensity to sunburn and tanning ability were strongly associated with both SK and SCC after multivariate modelling. The prevalence and predictors of EV-HPV infection in a subset of healthy controls with no solar keratoses was examined. Antibodies against at least one of the EVHPV types tested were detected in 14% of the tumour-free population; EV-HPV DNA was detected in 16% of normal skin biopsies and 40% of eyebrow hair samples. Across all three biomarkers increasing age was associated with a decreased risk of EV-HPV infection. The associations between EV-HPV and SK; and EV-HPV and SCC were examined using serum antibodies, EV-HPV DNA in normal skin and EV-HPV DNA in plucked eyebrow hairs. Overall EV-HPV seropositivity was positively and significantly associated with both SK and SCC. Seropositivity against multiple EV-HPV types was also positively associated with both SK and SCC, although the association was stronger and significant for SCC. Non-significant positive associations were observed between overall EV-HPV positivity in normal skin and both SK and SCC. SK and SCC cases were slightly more likely than controls to have EV-HPV positive eyebrow hairs. Combination analyses revealed a strong synergistic relationship between EV-HPV and markers of sun-sensitive skin types (fair skin, high propensity to sunburn, inability to tan) to increase the risk of SK and SCC. The joint effect of EV-HPV and UV on the risk of SK/SCC was clearly apparent in serological analyses. This effect was greater for SCC than SK. Discussion: This thesis used a molecular epidemiological approach with multiple biomarkers to investigate the association between EV-HPV infection and SK; and EV-HPV and SCC. Further evidence to support previous literature and the hypotheses is presented. Limitations and advantages of the present project are discussed with reference to existing literature.

Association between small mammals and vegetation on Fraser Island

Campbell, Paul — 2012-12-06T08:48:17Z

Association of Adiponectin Profiles with Dietary Carbohydrate Intake, Feeding, Gender, Body Weight, Fat Mass, and Insulin Sensitivity in Healthy Young Cats (Felis catus)

Heok Yit Tan — 2009-11-10T00:00:00Z

Adiponectin is an adipose-derived protein (adipocytokine) that is secreted by adipose tissue. It has insulin-sensitizing, anti-inflammatory and cardio-protective properties, and is thought to be protective against obesity-related diseases such as type 2 diabetes. Humans and cats are two species that commonly develop type 2 diabetes associated with insulin resistance, impaired beta cell function and spontaneous islet amyloid deposition. The domestic cat (Felis catus) has recently been proposed as an animal model for human type 2 diabetes. However, little is known about the physiology of adiponectin in cats. Therefore, we set out to investigate the association of adiponectin profiles with dietary carbohydrate intake, feeding, body weight, fat mass, and insulin sensitivity in healthy young adult cats (n=32; 2-4 years old; gender ratio 1:1; body condition 4-5/9). Cats were fed a moderate carbohydrate diet (37% ME) at maintenance energy requirements for four weeks. Cats were then assigned to either receive a low (19% ME) or high (52% ME) carbohydrate diet and fed at maintenance energy requirements for another four weeks, followed by ad-libitum feeding for eight weeks to facilitate weight gain. Adiponectin profiles including total circulating adiponectin and its distribution [low molecular weight (LMW) and high molecular weight (HMW) adiponectin], and proportion of adiponectin that is HMW (SA) were measured by ELISA and velocity sedimentation using sucrose gradients, followed by Western blotting, respectively. We demonstrated inter-animal variation in total adiponectin concentration at baseline (0.6 to 15.0 g/mL), with the adiponectin present in both LMW and HMW forms. Feeding with a high carbohydrate diet for four weeks at maintenance energy requirements resulted in increased total adiponectin concentration, which was associated with an increased concentration of LMW adiponectin. In contrast, feeding with a low carbohydrate diet for four weeks at maintenance energy requirements resulted in increased concentration of HMW adiponectin, decreased LMW adiponectin concentration, and increased SA, without a change in total adiponectin concentration. In cats fed the high carbohydrate diet, total adiponectin and HMW adiponectin concentrations become lower at six hours after feeding, as compared to the fasting concentrations. This phenomenon was not observed in cats fed a low carbohydrate diet, indicating a diet-dependent postprandial effect. There was no effect of gender on any of the adiponectin profiles in cats. Unlike other studies in humans and mice in which adiponectin concentrations decreased as fat mass increased, our data indicate that a moderate weight gain achieved by ad libitum feeding of a low carbohydrate diet for eight weeks correlated with increased adiponectin concentrations. Total adiponectin concentration (mirrored by HMW adiponectin) was positively correlated with body weight gain and fat mass gain (but not absolute fat mass) in our overweight cats. Furthermore, the fat mass-related increases in plasma adiponectin over eight weeks correlated with insulin sensitivity (higher adiponectin concentration corresponded to greater insulin sensitivity in overweight cats). These data hint at the possibility that in overweight animals, adiponectin is similar to other adipokines that rise concomitantly with increased of moderate fat mass gain and thus increases insulin sensitivity. Overall, the knowledge in this study therefore provides useful information to veterinarians and cat food manufacturers, and forms a foundation for future studies to extend our knowledge of adiponectin in cats. Data gathered in cats may also be applicable to humans and could therefore inform research using cats as an animal model of human obesity and type 2 diabetes.

Association, reciprocity, sharing and dependency : conditions of access and forms of inequality beyond the market state

Short, Patricia Margaret. — 2007-08-24T00:00:00Z

Associations among attachment security, dispositional and interaction-based measures of disclosure, and relationship functioning : a multimethod study of dating couples

Bradford, Steven A — 2007-08-24T00:00:00Z

A strategic management framework for reformed electricity generation firms in Eastern Australia.

Skoufa, Lucas A. — 2008-11-21T00:00:00Z

Strategy formulation for electricity generation firms in Eastern Australia in the environment of restructuring is the focus of this thesis. The ideological basis of electricity industry restructuring around the world has been based on neo-classical economics and the specific notion that firms in competitive markets are more efficient than vertically integrated government-owned monopolies. From a strategic management perspective it is assumed that firms will attempt to create a competitive advantage and accrue above normal profits, which contrasts with the requirement of the electricity regulatory regime view that no firm will make above normal profits or exercise market power. A review of literature on the economics of electricity markets is covered in Chapter 2, and Chapter 3 discusses the key aspects of strategic management including the concepts of competitive advantage and added value; among other matters the discussion in both chapters focuses on the various generation technologies available. For a commodity such as electricity there are limited options for firms to differentiate themselves and use of appropriate technology is seen as one of the best methods to achieve this. A Governance-Strategic Choice framework is proposed in Chapter 4 from the literatures in Chapters 2 and 3 and the propositions derived in these two chapters. A background case on the restructuring and privatisation of the UKESI is included as Appendix A and provides useful material for the development of the nine propositions and this in turn has assisted in the formulation of the GSC Framework in Chapter 4. The qualitative research design of the thesis is discussed in Chapter 5. The design is based on case studies of three electricity supply industries (specifically focused on the generation sectors); Victoria, Queensland, and New South Wales in the Australian National Electricity Market. The first case study, in Chapter 6, encompasses the restructuring and privatisation of the Victorian ESI generation sector. The second case study, in Chapter 7, encompasses the restructuring and corporatisation of the Queensland ESI generation sector and the final case study, also in Chapter 7, encompasses the corporatisation of the New South Wales ESI generation sector. It is important to note that the Queensland and New South Wales governments have not yet privatised their respective electricity supply industries. A consequence of this is that some worthwhile comparisons to the privatised Victorian Lucas Skoufa - A Strategic management framework for reformed electricity generation firms in Eastern Australiaindustry have been provided with regards to the strategic behaviours and choices made by electricity generation firms in these industries. Chapter 8 provides analysis of the Governance-Strategic Choice framework (derived in Chapter 4) and the nine propositions (derived in Chapters 2 and 3) by drawing on the three case studies presented in Chapters 6 and 7. Chapter 8 concludes by presenting a section on two strategic scenarios (use of appropriate generation technologies, including environmental considerations, and bundling of products) that are based on the GSC Framework, which provides guidance for strategy formulation for use by generation firms. Chapter 9 sets out the major conclusions of the thesis. In general, generation firms have maintained a majority of coal-fired technologies since privatisation/corporatisation; this situation has changed slightly but not enough considering that in the future greenhouse gas emission limits will most likely be imposed which will disadvantage the coal-fired technologies. Furthermore, risk management has been an important managerial tool for generation firms due to the price volatility experienced in the pool based trading system; in addition, the amount of regulation and regulatory change has been excessive in some cases. The main theoretical contribution of this thesis has been to provide a framework for generation firms to make strategic choices, and highlights two scenarios emanating from this framework for creating and maintaining a competitive advantage in the restructured electricity supply industry environment. For practitioners/senior management the contribution of this thesis is that they will have a better understanding not only of their strategic choices but also the strategic choices of competitors and have the knowledge that, apart from competing on price, there are several other strategic ways through which to create and sustain a competitive advantage.