UQ Theses (RHD) - Official collection - UQ eSpace

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 potential contribution of renewable energy to electricity supply in Australia: A study of renewable energy with a particular focus upon domestic rooftop photovoltaics, domestic solar hot water and commercial wind energy

Mills, David — 2008-11-21T00:00:00Z

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 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 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 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.

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 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.

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.

A Strategic Reformation: Change and Stability in Post-11 September Australian Strategic Policy

Hirst, Christian — 2008-11-21T00:00:00Z

The purpose of this thesis is to determine if the central paradigmatic assumptions that shaped Australian strategic policy prior to the 11 September (S11) terrorist attacks on the United States shifted over the four years between S11 and the end of 2005. To this point, the debate surrounding Australias strategic posture has not been informed by a rigorous and independent investigation into the post-S11 trajectory of Australian strategic policy. The core question this study will seek to answer is: has S11 produced a paradigm shift in Australian strategic policy? Methodologically, this study is presented as a single case study of intrinsic importance. Although the study has a narrative quality, it is essentially an investigation into Australias policy response to S11. The case study method will be employed primarily to deepen academics and policymakers understanding of what has been a crucial era in the history of Australian strategic policy. As such, the most appropriate theoretical approach is that of Foreign Policy Analysis (FPA). Unlike other theoretical paradigms, FPA does not seek to limit the range of actors or factors considered in the analysis of policy action. It is this flexibility and FPAs ability to allow for thick and rich descriptions of the factors affecting a states policy trajectory that endear it most to this study. The study has found that, as a result of the perceptual shock of S11 and the subsequent efforts of key political and bureaucratic actors, the Australian governments formalised view of the security environment has transformed and its perceptions of the role and utility of Australias Defence Force (ADF) and the United States alliance have changed in important ways. Despite this, budgetary, political and cognitive stabilisers have prevented the formal enunciation of new post-S11 strategic posture. Despite claims to the contrary made by senior members of Australias strategic policy community, this study shows that there is little doubt that the worldview underpinning the Australian governments approach to strategic policy in late 2005 was significantly different from that which shaped Defence 2000, the governments last formal expression of strategic doctrine prior to S11. Such a change is indicative of a paradigm shift. While no new coherent strategic policy paradigm has yet taken the place of pre-S11 guidance, the strategic ideas and strategic actions of the Australian government between 11 September 2001 and the end of 2005, in the judgment of this study, are representative of the early stages of a major reformation in Australias strategic orientation.

A strategy for fatigue risk management at a mine site

Maxwell, Adrian og Lang, Heath — 2009-10-15T00:00:00Z

Fatigue in the minerals industry of Western Australia is a greatly under-recognised issue that has serious potential consequences for shift workers at work and at home. A review of fatigue literature demonstrates the elusive nature of fatigue. It is something that most people have probably experienced at some time in their lives. It is a diffuse sensation that is accompanied by feelings of lethargy and a lack of interest in any activity. A general sensation of weariness is a major symptom of fatigue. Fatigue cannot be measured directly and subjective estimates have to be relied upon. Potentially life threatening consequences can result when shift workers perform under the influence of fatigue. Fatigue and sleepiness have the power to kill if not treated with the respect they deserve. A cross-sectional survey of five underground mines was conducted to obtain a better understanding of their fatigue risk management strategies and the views of managers and shift workers on their sleep and shift schedules. Four mines provided information on their fatigue risk management procedures. Ten underground mining crews comprising 147 shift workers provided their views by an anonymous survey questionnaire administered at each mine at the start of shift. Shift worker sleep at the five mines compared well with mines in Tasmania, New South Wales and Queensland. However, it was found that frequently waking earlier than intended was the most widely reported sleep concern for shift workers on day shift, night shift and days off. Falling asleep while on day shift and on night shift demonstrates that fatigue is an issue that can occur on day shift as well as night shift. Fatigue is not an issue that is confined to night shift. Mine fitness for work procedures focused primarily on: shift schedules, hours of work and drug and alcohol issues. The level of detail provided on fatigue risk management was considered to be less than adequate when compared with the three previous issues and fatigue risk management documentation sourced from the minerals industry and the transport industry. The survey data and fitness for work procedures provided by four mines suggests that considerably more work needs to be done to recognise and address sleep quantity and quality, as well as sleepiness and fatigue experienced by shift workers while on shift and at home on rest days. There is a serious need for the Western Australian minerals industry to recognise the vital importance of sleep to shift workers during their shift schedule and rest days. There needs to be a concerted and on-going campaign by the industry to raise and maintain the awareness of sleep as a key element in fitness for duty.

A structural and functional characterisation of caveolae

Ariotti, Nicholas Richard — 2013-02-22T07:48:32Z

A structural genomics approach to the structure determination of macrophage proteins

Kai-en Chen — 2011-11-15T00:00:00Z

Macrophages are cells differentiated from circulating blood monocytes that represent the first line of defence against pathogen invasion. Macrophages are widely distributed throughout the body, which comprising 15% - 20% of cell populations in many organs and are particularly abundant at the route of pathogen entry. They play a critical role in immune defence by initiating, promoting, preventing, suppressing or terminating immune responses. Macrophages act as a key player in both the pro-inflammatory and anti-inflammatory responses. Characterisation of important macrophage proteins could helps to understand the molecular mechanisms of macrophages in these responses. We established a high-throughput pipeline at the University of Queensland to investigate the structures and functions of novel macrophage proteins. This PhD project began with the selection of 12 novel, biologically interesting and crystallization-feasible targets that were then designed into 96 different constructs. Processing of the 96 constructs was performed in parallel using simple automated applications of ligation-independent cloning, small-scale bacterial expression, small-scale purification and solubility assessment. After processing these 12 targets, I found that 16 constructs of three targets yielded soluble protein. From the three soluble targets, I focused on two proteins BinCARD and Fam96a, because in the meantime the third target was solved by another group. Bcl10 interacting CARD protein (BinCARD) is a CARD-domain containing protein that was reported to interact with Bcl10 through CARD-CARD interactions to down-regulate NF-κB transcription factor activation. The crystal structure of BinCARD solved at 1.5 Å resolution revealed six anti-parallel α-helices, showing that this protein is similar to other CARDs of known structures. Before progress toward the interaction study between BinCARD and Bcl10, I also addressed the bottleneck of expressing Bcl10 as soluble protein. Several rescue strategies were used including expression using different constructs and bacterial strains, insect cell system, and matrix-assisted refolding strategy. Carma1 was introduced as a positive control for the BinCARD and Bcl10 interaction study. GST-pull down assay suggests that dimerisation of Bcl10 is required for its interaction with Carma1. However, I have not yet been able confirm an interaction between BinCARD and Bcl10 interaction. Family with sequence similarity 96, member a (Fam96a) is a novel DUF59 domain containing protein that belongs to a group of diverse proteins with no function characterised yet. The crystal structures of Fam96a at 1.8 Å resolution revealed two different types of novel domain swapped-dimer conformation, a major dimer and a minor dimer. I also confirmed by chemical crosslinking and size-exclusion chromatography that Fam96a forms a complex with cytosolic iron-sulfur protein assembly 1 (Ciao1). Crystals of the Fam96a and Ciao1 complex were obtained and diffracted to 7.0 Å resolution.

A STRUCTURAL USE OF RENEWABLE LIGHTWEIGHT MATERIAL

Goh, Gim Yau — 2008-11-21T00:00:00Z

This thesis investigated the structural adequacy of using a renewable lightweight material, bamboo, to construct a commonly used lattice structure, double layer grid, in a dimension of 2.6m x 2.6m x 0.9m. The structural potential of two Australian grown bamboo species, Phyllostachy Pubesecens and Phyllostachy Bambusoides, were conducted through compression, bending and buckling tests. A structurally stronger bamboo specie was then chosen to build the grid and subjected to a total load of 10kN testing. Material elastic geometry non-linear analysis using high order beam-column elements were performed to predict the deformation characteristics of the grid for comparison with test data. An important feature of this project was the development of a lightweight PVC (polyvinyl chloride) joint system, consisted of hub and connector, to connect bamboo members. The designed joint system was simple, efficient in fabrication and assembly, and was economical. Finite element method (FEM) was adopted to establish the detailed configuration of the joint and to perform both material and geometry linear structural analysis. A total of 8 joint prototypes were tested under load cases of tension, compression and bending, and the results were validated with FEM. This thesis proved that Mao Jue was mechanically strong for structural application, and the proposed new joint system worked well with bamboo in the grid.

A study of allergic reactions to beta-lactam antibiotics in an adult cystic fibrosis unit

Burrows, J. — 2007-08-24T00:00:00Z

A study of bioactive compounds in selected Australian native plants and products

Sommano, Sarana — 2008-11-21T00:00:00Z

The bioactive properties of food and their relationship to the maintenance of health and protection from degenerative diseases are receiving much attention from nutritionists and consumers. Eating fruits and vegetables is strongly recommended for good health and a desirable intake of antioxidants. Thus the trend in the food industry is toward producing functional foods with increased levels of bioactive compounds. One of the reasons that Australian native plants have become commercial ingredients is that they personify truly Australian cuisine. There is growing interest in value adding native food plants for local and export markets. There is also an increasing interest in the bioactive components of native plants and as a result identifying a role for native plant foods in the functional food market. However there are a number of commercial issues facing native food producers and food processors in delivering consistent quality products to commercial end users based on a food technology and nutrition platform. Some specific bioactive compounds were measured. Lycopene, β-carotene and ascorbic acid were determined by HPLC. The method for determining lycopene and β-carotene required optimisation. It was found that the accuracy of measurement of lycopene and β-carotene was improved if the sample was finely blended to release the lycopene from the food matrix to maximise extraction. Considerable losses were found during the measurement of ascorbic acid by HPLC. An oxygen quenching agent, sodium metabisulphite, was used to delay the rate of ascorbic acid degradation. The rate of addition at 500 μg/mL was found to be very effective. Moreover, since the degradation kinetics can be expressed as a first order reaction, the rate constant k was calculated for each sample. Since loss of ascorbic acid was still observed during long HPLC sequence runs, the k values were used to extrapolate back to the initial ascorbic acid concentration in the samples. Only Australian native plants currently used as commercial ingredients were selected and used through out the work. These were bush tomato, Kakadu plum, wild lime, finger lime, Davidsons plum, wattle seed and lemon myrtle. The post harvest and handling procedures of all of those above plants were documented. The information was gathered from the farmers, distributors, representatives of Aboriginal community and from the literature. The samples were also collected and tested for bioactive compounds. It was found that post harvest methods of the native plants had an effect on the survival of bioactive compounds. There are two documented post harvest and handling methods for bush tomato, sun and oven drying. Sun drying seemed to give a better appearance however there was lower survival of bioactive compounds. Most of the native plant fruits are frozen for sale commercially. It was found that for the frozen fruit, the levels of bioactive compounds fluctuated probably due to differences in size and species. Bush tomatoes are one of the most commonly used native fruits and these and other native fruits are frequently made into sauces, chutneys and jams. The stability of bioactive compounds is therefore of importance in these kinds of products. A shelf life study was carried out on bush tomato sauce and chutney. Lycopene was measured in the products together with sensory and colour measurements throughout a period of 9 months. The effect of light and temperature was studied. Lycopene was affected by all of the factors and the study also showed changes in colour and flavour in the products. The behaviour of bioactive compounds during processing was studied. Samples were collected during the production of commercial sauces. Bush tomato ketchup, chutney and Kakadu plum chilli sauce were sampled from the start, middle and the end of the processing run. The samples were tested for specific bioactive compounds; lycopene for bush tomato sauces and ascorbic acid for Kakadu plum sauce. The studies showed that lycopene content was constant through out the run for both bush tomato sauces. Similarly, for the Kakadu plum sauce, ascorbic acid content was constant. However the losses appeared to have taken place prior to the making of the final sauce. The effect of heat processing on bioactive compounds was studied on a laboratory scale product. Formulated bush tomato and Kakadu plum sauces were made in the laboratory and also were tested for specific bioactive compounds. Lycopene content increased by 48 % which can be explained by the release of the lycopene from the food matrix. In contrast, there was a large loss of ascorbic acid in Kakadu plum sauce during the heating process. There are two aspects to the food safety issues in dealing with the use of Australian native plants. First, finding ways to eliminate toxic compounds is essential. For example, it is recommended that bush tomato be collected at the ripe and dried stage when any toxins are at a minimum. Second, during the processing of the products, the critical control points need to be carefully tested in order to protect the products from any contamination. The antioxidant capacity of native plants using DPPH, TEAC and total phenol assays was determined. A positive correlation was found between the DPPH and TEAC assays but not between either of these with total phenol content. Kakadu plum was found to be the most effective antioxidant containing plant. However, the results showed relatively low antioxidant activity in Davidsons plum even though it contains a high amount of total anthocyanins (polyphenols). This could be due to the colour of the fruit extract interfering with the measurement of antioxidant activity because ABTS radical used in the TEAC assay is purple. LC-MS was used for the analysis of flavonoids and anthocyanins in a number of native plants. Davidsons plum was analysed differently due to the large amount of anthocyanin detected. A lower cone voltage was found out to give a better anthocyanin M+ molecular ion plus fragment ions for the sequential loss of sugar molecule and finally the anthocyanidin M+ ion. The results shown that 6 anthocyanins were found which are in order of decreasing concentration: delphinidin-hexosepentose, cyanidin-hexose-pentose, petunidin-hexose-pentose, pelargonidin-hexose, peonidin-hexose and malvidin-hexose.

A Study of Blast Induced Rock Mass Displacement Through Physical Measurements and Rigid Body Dynamics Simulations

Alan Tordoir — 2010-04-23T00:00:00Z

Abstract In open pit mining operations, blast induced rock mass displacement can have a significant impact on ore recovery and downstream productivity. A comprehensive review of the literature has shown that quantifying displacement on a regular basis has generally been limited by the complexity involved in measuring the process. As a result, various empirical and numerical modelling approaches have been developed to estimate the magnitude of displacement for given blast design inputs. Advanced three-dimensional numerical approaches are limited by their computational requirements and are yet to be routinely applied to full scale conditions. The use of simpler numerical approaches have shown potential but previous attempts have been limited by the oversimplification of boundary conditions, disregard for key processes such as inter-particle collisions and are generally two dimensional in nature. The implementation of these models within the production environment has been onerous as a result of the numerous calibration parameters required to generate reliable results. The recent development of the Blast Movement Monitoring (BMM) system and advances in software and hardware dedicated to computational rigid body dynamics, have facilitated new avenues in which blast induced rock mass displacement can be studied and modelled. The main objective of this thesis is to improve our knowledge of the key factors that influence rock mass displacement through: • the analysis of direct physical measurements of full scale production blasts; • and the development of a practical three dimensional blast movement modelling framework aimed at the production stages of operating mines. To gain a better understanding of the main factors which control rock mass displacement in open pit production blasting environments, a comprehensive analysis of physically measured displacement data has been conducted using a combination of advanced data mining and classical statistical techniques. Three main data sets were used for this analysis, including existing data published as part of two Masters thesis from the Mackay School of Mines; data collected during the development of the BMM system at the University of Queensland’s Julius Kruttschnitt Mineral Research Centre (JKMRC), and new data collected as part of this thesis to supplement the sparse areas within the Mackay and JKMRC data sets. This new data set was gathered at the Mogalakwena Platinum Mine in the Republic of South Africa. Results from the analysis of the three data sets has shown that the main parameters controlling rock mass displacement in open pit production blasting include the three dimensional explosive energy distribution, the orientation of timing contours and confinement effects such as the distance from the free face and stemming influence. These parameters provide the basis from which displacement outcomes such as the magnitude and direction of movement can be estimated and allowed the development of a novel framework to model blast induced rock mass displacement in three dimensions. The proposed modelling framework takes a mechanistic approach by combining rigid body dynamics with established empirical relations and material properties to simulate the displacement of the rock mass under specified blasting conditions. To improve on the current limitations of existing models, the framework addresses six major requirements. These are: 1. the ability to model displacement in three dimensional space while taking into account particle interaction, 2. the ability to incorporate input parameters available to engineers onsite, 3. the ability to model the transition from unconfined to confined blasting conditions, 4. the ability to run within a reasonable time frame, 5. the ability to be calibrated to production blasting conditions using existing technology, and 6. the ability to build models that can be linked directly to block modelling techniques found in geological and mine planning software. The modelling framework consists of a discretised block model of the blast volume that can be described by the positions and orientations of the blocks at each time step during the simulation. All blocks are assigned two initial conditions based on spatial energy distribution and timing contour analysis. These initial conditions define the blocks initial displacement vector prior to the rigid body dynamics program’s particle collision algorithms taking over. To account for the loss of shock and ineffective energy during the breakage process, an energy loss weighting factor is applied to the calculated energy values. Results from three case studies of full scale production blasts have shown that the model generally responds well to the horizontal component of the three-dimensional displacement vector but is less accurate in the vertical displacement direction. This is the first time that a three dimensional displacement model has been evaluated against actual sub-surface displacement data. The model evaluation has indicated that the introduced energy loss factor can be successfully used as a calibration parameter. For all three case studies, the model ran within a reasonable time frame, the longest averaging 45 minutes to simulate a blast volume in the order of 125,000 m3. Detailed analysis has also helped identify the main limitations of the current framework and directions for future work.

A Study of Cynicism and Organisational Disengagement in the Workplace

Gareth John Snowden Simpson — 2012-05-01T00:00:00Z

Employee cynicism is now widely acknowledged to be a complex phenomenon that pervades many contemporary workplaces. Yet, while considerable research attention has been directed towards understanding the effects of cynicism on workplace outcomes, there remains little consensus regarding the precise nature of cynicism and the role it performs in shaping individuals’ relationship with their organisation. While some conceptual research acknowledges that cynicism is capable of existing as a ‘malignant’ or a ‘benign’ force in organisations, capable of affecting some individuals and the organisations in which they work more or less negatively than others, few empirical explanations have been provided to account for this duality. Cynicism research as a whole has been criticised for its lack of theoretical development, despite attempts by researchers from diverse backgrounds to fit the construct into various theoretical frameworks. However, in competition with the majority of mainstream research applications of cynicism, one conceptualisation of cynicism has emerged which characterises it as a rational defence strategy fostering the disengagement of the individual from the organisation. This element of organisational disengagement (OD), proposed to lie at the heart of employee cynicism, has been suggested to be a driving force behind how individuals interact with their organisations. Organisational disengagement is a conceptual space that has not been adequately addressed by existing research. I argue that extending cynicism research by understanding and investigating the disengagement it is capable of engendering between employees and their organisations provides an intuitive way to understand the link between cynicism and workplace outcomes. Further, better understanding the nature and extent of the organisational disengagement created by employee cynicism provides a means through which to explain how cynicism affects different individuals and organisations differently. The aim of this research is to explore and operationalise the concept of organisational disengagement in a contemporary organisational context. In this thesis, I focus on exploring organisational disengagement in the context of employee cynicism, which has been proposed by a small group of researchers to a major force behind the psychological separation of the individual from their organisation. I propose that organisational disengagement performs an important role in determining how workplace defences such as employee cynicism manifest as organisational outcomes. Moreover, I propose that organisational disengagement itself may act as a more powerful predictor of attitudes and behaviours at work than employee cynicism and other organisational phenomena. To these ends, I conducted three studies. Study 1 was conducted in order to investigate whether organisational disengagement is experienced by employees facing undesirable or negative events at work, and, further, to document the nature and extent of this disengagement from the organisation. Phenomenological interviews were conducted on a sample of 15 working individuals within a large Australian university. Findings from the study suggested that organisational disengagement is, indeed, experienced by individuals — cynical or otherwise. Participants reported that their disengagement was commonly experienced in four distinct ways: as cognitive withdrawal (OD-CW), behavioural withdrawal (OD-BW), emotional divestment (OD-ED), and as a separation of the self-concept from the organisation (OD-SS). These dimensions of organisational disengagement were not mutually exclusive; rather, participants reported experiencing multiple dimensions simultaneously, suggesting that the four dimensions uncovered in this study might be used to create a profile of an individual’s organisational disengagement, which may account for individual differences in the outcomes of change. In Study 2, I developed and validated scales to measure each of the four OD dimensions using established scale development procedures and multiple samples. Study 3 was designed to assess the performance of the four OD measures, and of an overall, latent OD variable in explaining attitudinal and behavioural workplace outcomes, alone and in conjunction with employee cynicism. Self-report questionnaires were used to collect data from a sample of working individuals from a diverse range of organisations and industries. Structural equation modelling techniques were used to test the hypothesised relationships between cynicism, OD, and sets of attitudinal and behavioural outcomes. Results suggested that OD was associated with organisational commitment and job satisfaction, partially mediating the effects of cynicism. OD was also found to be negatively related with three organisational citizenship behaviours, again mediating the effects of cynicism on these outcomes. Overall, the findings from this body of research provide support for the organisational disengagement construct being worthy of empirical investigation. Further, they provide evidence of the ability of OD to profile the disengagement produced by defence strategies including cynicism, emplaced by individuals in order to control their interaction with the organisation at which they work. By operationalising organisational disengagement, this thesis makes a contribution to the theoretical understanding of employee cynicism and organisational disengagement, and, in applied settings, allows for organisations to understand and monitor the extent to which individuals are psychologically connected to their organisation.

A Study of Dominant Discourse on News-Making Decisions in Indonesian Newspapers (A Case Study of News Coverage of the Bali Bombing of 2002)

Aziz, Syamsuddin — 2008-11-21T00:00:00Z

This study is to evaluate the influence of dominant discourse on news-making decisions affecting the coverage of the Bali Bombing 2002 by the Indonesian newspapers KOMPAS, Republika, and Bali Post. Norman Faircloughs Critical Discourse Analysis method has been chosen for this study, since it provides two levels of analysis, textual level and discursive level. In the case of the textual level analysis, the texts of the news stories from the three newspapers were analysed and at the discursive level of analysis, results from observations of newsroom procedure and interviews with journalists were analysed. The discourses revealed were examined to ascertain which discourses were dominant at what time and in which news organisation in order to uncover the reason for the influence and the dominance. In most cases, the dominant discourses reflected in the stories of each news organisations coincided with the opinions of the majority of the staff and owners of that news organisations.

A Study of Generation Investment Into the Australian’s National Electricity Market

Kin Onn Wong — 2010-09-26T00:00:00Z

The deregulation of the electricity industry had fall short of recognising the uniqueness of electricity. As electricity produced has to be instantaneously consumed, while ensuring that the power system is secure at all time. However, short term issues such as demand variations resulting in uncertain pool prices, market inefficiencies, participants’ displaying strategic behaviours will all contributed to short term market problems. Such short term issues can aggregate into long term investment problems, effectively setting up market barriers against new generation investments or research into new technologies. This thesis sets out to address the above short and long term problems in the context of the Australia National Electricity Market (NEM) . The market operator of the Australia NEM utilises a Linear Programming (LP) optimisation engine to dispatch generators into production. Despite LP speed in convergence to an optimum solution, the boundary search technique may not offer sufficient optimum dispatch outcomes. A chapter in this thesis presents the application of Genetic algorithms in the solving of market dispatch problem similar to that performed by the market operator. This study has indicated that transmission capacities can be better utilised when dispatch problem is optimised by genetic algorithm, potentially offering interconnected regions greater ability to share reserves. A hybrid model was proposed in one of this thesis chapter to forecast pool prices based on historical price demand characteristics. The area of pool price forecasts was a well study area, with a number of well established time series and data mining models. However, this model proposed seeks to reduce computation resources while producing accurate forecasting results by creating dependency of the forecast pool prices with the variations in system demand. This model enables more efficient forecast of pool prices based on prices respond characteristic to variations in system demand. This allows users to perform greater range of sensitivity studies. In some occasions, the NEM pool prices are not driven by increases in demand or network constraints; but participants exhibiting strategic behaviour through rebidding their capacity offers at higher price bands. An agent based model was detailed in one chapter of this thesis to model such behaviour. The model consisted of several modules emulating the processes a typical market participant will perform when trading in the market. The study noticed that that when the marginal generator game the market at times of tight demand-supply condition, the pool prices would not reflect optimum market outcomes. New generation capacity is a crucial part in ensuring supply demand balance in the NEM, therefore second half of this thesis is devoted to present works performed in long term generation investment issues. In the Australia NEM the market operator can only inform market participants of new capacity opportunities within a set range of study scenarios and conditions. To expand the number of scenarios that can be study, an integrated model is proposed in this thesis. The proposed model look at new generation entry using market simulation results from a market simulator. The model begins with the market simulator stepping through the simulation horizon annually, where the simulated results are then feed into the proposed new entry evaluation module. This proposed new entry evaluation model will then select a new entry with the highest economic return to enter the market. The selected new entry must fulfil a list of criteria which includes cost recovery, resource availability, construction time and the overall system adequacy. In the case study performed, it was noticed that when the pool prices were sufficiently high to support the investment of most new entrants in the new entry list, units with the shortest construction time and lowest capital cost such as an Open Cycle Gas Turbine will be the first to enter the market. Enhancements were added later in the form of risk evaluation of prospective projects within a single scenario. This enhancement potentially enables investors to perform several studies of prospective projects. In this enhanced model, the risk represented expected revenue distributions due to outages of the new entrant. This will also allows investors with greater insight on the risk a potential new entry is likely to face when it enters the market. In summary, this thesis identify knowledge gap in the Australia NEM and hence set out to address some of these vital short and long term issues that are important to the structural health of the NEM.

A study of motivation through repertoire in intermediate cello students

Berry, Anne Irma — 2008-11-21T00:00:00Z

The decision to research motivation through repertoire in intermediate cellists arose from two different perceived areas of need. Firstly, it was found that there was a scarcity of availability and accessibility of Australian compositions for intermediate cellists. Secondly, the literature suggested that there was a need for the further research of intrinsic motivation in the field of instrumental pedagogy. A review of the literature found that research into intrinsic motivation in instrumental pedagogy was mostly related to the 'process' of developing and maintaining motivation. Of the research which examined the aspect of 'content' in the maintenance of intrinsic motivation, this was mostly related to 'student choice'. This study emerged as a way of providing information to composers and teachers about what aspects of repertoire may be motivational. It investigates intrinsic motivation by questioning students and their teachers about which aspects of music repertoire are most likely to inspire students to practice more and strive for excellence. A discussion of the philosophies of Bruner and Csikszentmihalyi is included to give meaning and context to 'intrinsic motivation' in instrumental pedagogy. Research was conducted through purpose-designed questionnaires distributed to cello teachers and their students in Queensland. Questionnaires for teachers and students were very similar although the student questionnaire was a little shorter. The questionnaires gathered information on the most frequently used general teaching repertoire, as well as teachers experiences in teaching contemporary and Australian repertoire. Musical aspects investigated included style, emotional content, harmony, articulation, tempo (speed), tonality, and rhythm as well as cellistic techniques. This information was balanced with questions regarding the technical developmental requirements perceived necessary for intermediate students. In comparison with other motivators such as verbal encouragement, ensemble participation and preparation for performances and exams, repertoire was found to be a significant motivator for 'students' best work'. Students' preference for challenging music, or by contrast, beautiful music was a persistent theme throughout the results. The three characteristics which were nominated as most motivating by both teachers and students were fast and lively, from the Romantic period and for cello and piano. The strongest difference between results for teachers and students was on the characteristic of folk feel which produced opposite results for the two groups of respondents. Some differences were also found within the respondent groups on the basis of gender and age. It is noted that students acknowledged the benefits of learning more advanced aspects of technique, such as thumb position, in expanding the pool of repertoire which they would be able to play. It was confirmed that Australian repertoire was not often taught to students at this level and that this was, at least in part, because of a lack of availability. Suggestions have been made for both composers and teachers in choosing techniques and repertoire for intermediate students. However, the importance of asking students about their preferences is borne out by the volume and detail of students' individual responses. Also, by questioning their students, teachers are likely to be stimulating the valued development of 'metacognitive strategies' in adolescent students.

A study of one-dimensional quantum gases

Andrew Sykes — 2010-02-01T00:00:00Z

In this thesis we study the physics of quantum many-body systems confined to one-dimensional geometries. The work was motivated by the recent success of experimentalists in developing atom traps, capable of restricting the motion of the individual atoms to a single spatial dimension. Specifically, we look at aspects of the one-dimensional Bose gas including; excitation spectrum, correlation functions, and dynamical behaviour. In Chapter \ref{ch:excitation1D} we consider the Lieb-Liniger model of interacting bosons in one-dimension. We numerically solve the equations arising from the Bethe ansatz solution for the exact many-body wave function in a finite-size system of up to twenty particles for attractive interactions. We discuss novel features of the solutions, including deviations from the well-known string solutions due to finite size effects. We present excited state string solutions in the limit of strong interactions and discuss their physical interpretation, as well as the characteristics of the quantum phase transition that occurs as a function of interaction strength in the mean-field limit. Our results are compared to those obtained via exact diagonalization of the Hamiltonian in a truncated basis. In Chapter \ref{ch:g2} we analytically calculate the spatial nonlocal pair correlation function for an interacting uniform one dimensional Bose gas at finite temperature and propose an experimental method to measure nonlocal correlations. Our results span six different physical realms, including the weakly and strongly interacting regimes. We show explicitly that the characteristic correlation lengths are given by one of four length scales: the thermal de Broglie wavelength, the mean interparticle separation, the healing length, or the phase coherence length. In all regimes, we identify the profound role of interactions and find that under certain conditions the pair correlation may develop a global maximum at a finite interparticle separation due to the competition between repulsive interactions and thermal effects. In Chapter \ref{ch:casimirdrag} we study the drag force below the critical velocity for obstacles moving in a superfluid. The absence of drag is well established in the context of the mean-field Gross-Pitaevskii theory. We calculate the next order correction due to quantum and thermal fluctuations and find a non-zero force acting on a delta-function impurity moving through a quasi-one-dimensional Bose-Einstein condensate at all subcritical velocities and at all temperatures. The force occurs due to an imbalance in the Doppler shifts of reflected quantum fluctuations from either side of the impurity. Our calculation is based on a consistent extension of Bogoliubov theory to second order in the interaction strength, and finds new analytic solutions to the Bogoliubov-de Gennes equations for a gray soliton. In Chapter \ref{ch:solitons} we study the effect of quantum noise on the stability of a soliton. We find the soliton solutions exactly define the reflectionless potentials of the Bogoliubov-de Gennes equations. This results in complete stability of the solitons in a purely one dimensional system. We look at the modifications to the density profile of a black soliton due to quantum fluctuations.

A Study of Ore Breakage Characterization for AG/SAG Mill Modelling

Stephen Larbi-Bram — 2010-03-18T00:00:00Z

Abstract In the existing JKMRC breakage testing method for AG/SAG mill modelling, ore is characterised using mainly high energy single impact tests. However, recent DEM studies have suggested that breakage in AG/SAG mills is mainly due to low energy repetitive (or multiple) collisions rather than single high energy impacts. Furthermore, several of the published AG/SAG ore hardness tests developed outside the JKMRC use laboratory tumbling mills to quantify the specific power required to grind the ore to a set product size. Comprehensive experiments were carefully designed using two mill diameters of 1.1 and 0.6 m to mimic the reported low energy repetitive impact breakage under low load conditions. The ore breakage characterisation parameters derived from high energy single impact tests were used to predict the low energy repetitive impact breakage behaviour. Significant bias has been shown to be associated with the traditional high energy single impact characterisation approach, suggesting an alternative method was required. An extensive experimental program with more than 1400 tests was conducted using a newly developed JKRBT (JKMRC Rotary Breakage Tester) device, gravity drop test and laboratory tumbling mills. Comprehensive data were collected and analysed to provide an understanding of low energy repetitive impact breakage of particles and high energy single impact breakage. Details of the experimental study and findings are presented in Chapter 5. A breakage characterisation model has been developed, which takes into account the various impact energy classes and their associated body breakage and surface breakage responses. The breakage conditions were analysed and used to derive two sets of impact breakage parameters (body breakage and surface breakage). These parameters were then combined using a procedure believed to account for the two key breakage modes in tumbling, and successfully applied to predict the breakage in the two laboratory tumbling mills. Chapter 6 presents the breakage modelling approach and results. Based on the understanding of different breakage modes, a novel particle breakage characterisation method for AG/SAG mill modelling has been proposed and validated. Different from the prior-art JKMRC approach in which the breakage tests are conducted at high energy single impact, the proposed method incorporates high energy single impact, low energy multiple impacts and a simplified tumbling test. Both breakage probability and degree of breakage are used to characterise the breakage behaviour of ores. The details of the new characterisation method can be found in Chapter 7. The studies conclude that • The JKRBT can be used to investigate rock breakage characteristics under single and repetitive impacts; • The breakage of rocks in tumbling mills (under very low load conditions) can be likened to the low energy JKRBT repetitive impact breakage. • The behaviour of particle breakage as observed in AG/SAG milling can be modelled using a combination of JKRBT and tumbling ore breakage characterization; • A methodology for ore breakage characterization for AG/SAG mill modelling has been proposed and validated using independent sets of ores samples.

A study of participative assessment and reflections on learning among first year medical students

Papinczak, Tracey Ann — 2008-11-21T00:00:00Z

A Study of the Effects of Dairy Farmers' Personalities on Their Risk Attitudes, Decision Making Processes and Risk Management

Marchant, David Durack — 2008-11-21T00:00:00Z

Abstract The aim of this study was to understand the relationships among the personality traits, risk attitudes, risk management practices, and decision making processes of dairy farmers in SE Queensland. Risk management and decision making processes are two of many components of managerial ability. The hypothesis was proposed that dairy farmers personalities influence their risk attitudes, decision making processes, and risk management abilities. Case studies of 46 dairy farmers in SE Queensland involving the completion of personality inventories (NEO-PI-R) based on the Five-Factor Model of personality; questionnaires and informal interviews were used to test the hypotheses. The thesis contains three parts. The first part, Chapter 1, is the introduction to the thesis. The second part of the thesis, Chapter 2 through Chapter 6, consists of an extensive review of the literature on the major topics pertinent to the project. In Chapter 2, a definition of competence in the context of this study is given, and an explanation of the evidence for a connection between personality and competence and thus job performance is detailed. In Chapter 3, the literature on personality is reviewed with particular emphasis on trait theory and the development of the Five-Factor Model of personality (FFM). In Chapter 4, the literature review on personality assessment using testing instruments designed for use in the context of the FFM is presented, and the rationale for the personality test instrument is expounded. It is the task of the manager to manage risk, so that considering risk attitude when making decisions is also an integral part of the study of the role of managers. Chapter 5 reviews the contemporary literature on risk and risk management with an emphasis on the application of risk management principles to dairy farms. In Chapter 6, the literature on decision theory is reviewed. Decision-making and risk management are intertwined. The behaviour resulting from the process of making a decision reflects the personality and risk attitude of the decision-maker. In this chapter, the distinction is made between formal and informal models of decision making, and examples are given. The third part of the project comprises Chapters 7 through Chapter 11. Chapter 7 outlines the research approach used case studies - and paves the way for the following two chapters, which present a qualitative and a quantitative analysis of the data from the case studies. Chapter 8 presents part 1 of the investigation - the qualitative analysis of the case studies. This chapter introduces and explains the terminology used in the questionnaire and examines the trends and feeling in the farmers answers. Chapter 9 presents part 2 of the analysis quantitative results of the personality assessments and interviews from the case studies with SE Queensland dairy farmers which were conducted to assess their risk management and decision making abilities. Chapter 10 provides a summary of the research findings, and then discusses the results with respect to the diverse responses of farmers to common external pressures. The chapter discusses the relevance of personality to the formation of management strategy and concludes with a short introduction to systems thinking as a way of thinking about the complex systems inherent in dairy farming. Chapter 11 reviews the subjects covered in the thesis and draws conclusions from the research. It outlines implications for policy makers and managers and proposes directions for further research in this area of investigation. Key Words: Five-Factor Model of Personality, risk, decision making processes, dairy farmers, management

A study of the efficacy of Australian phytochemicals encapsulated in clay nanoparticles as pesticides against Helicoverpa armigera (Hübner) and Myzus persicae (Sulzer)

Degefu, Teshale — 2012-11-01T00:00:00Z

A Study of the Epidemiology of Sporadic Campylobacter Infection in Australia

Russell Stafford — 2010-07-21T00:00:00Z

Campylobacter is currently the most common cause of acute bacterial diarrhoea in Australia among all the notified enteric pathogens with more than 15,000 cases each year. The incidence of notified campylobacteriosis has steadily increased during the past 15 years from 67.0/100,000 population in 1991 to 121.4/100,000 in 2005, though the factors contributing to this increase had not been studied. Adjusting for under-reporting there are, at this point in time, an estimated 225,000 infections occurring each year in Australia, most of which are sporadic in nature. Much of our knowledge in Australia about risk factors for sporadic disease has been based on overseas literature. Prior to the studies undertaken in this thesis, the epidemiology of Campylobacter infection had not been thoroughly studied in Australia, nor had there been any national studies examining risk factors for locally-acquired infection. The broad aim of this thesis was to examine in depth the descriptive epidemiology of Campylobacter infection in Australia, explore the reasons for the sustained increase in incidence of infection and to identify the major risk factors for locally acquired infection using a multi-centre case-control study design. The descriptive study of the epidemiology of campylobacteriosis in Australia was based on Australian notifiable disease surveillance data collected over a 15-year period between 1991 and 2005. This study described the key epidemiological characteristics of this disease in Australia and identified some significant differences in incidence trends across states and territories and among different age groups which had not been previously reported. The study identified gaps in our knowledge of this disease in Australia and made recommendations for future research including the investigation of factors associated with the decline in incidence of infection among children aged  4 years and further studies to identify age and sex-specific risk factors for infection. The issue of seasonality, transmission routes and infection was addressed and areas for further research were specified including longitudinal studies at a regional level that incorporate a comparison of human, animal and environmental genotypes. This study also provided strong compelling evidence to support the hypothesis that the increase in notification rates in Australia during this period represented a real increase in the incidence of infection and that the main driving force behind this rise has been the ongoing increase in chicken consumption among the Australian public. The multi-centre case-control study, involving 1,714 participants  5 years of age, identified the major foodborne and non-foodborne risk factors for Campylobacter infection among the general population in Australia. This study confirmed that chicken meat is a major source of sporadic infection in this country and is responsible for almost one-third of all cases that occur in the Australian community each year. Other independent risk factors for sporadic infection in Australia included consumption of offal and ownership of domestic dogs or chickens aged  6 months. The Nagelkerke R² value of 16% for the final multivariable model indicated a considerable proportion of our case-patients had unexplained risk factors. The combined population attributable risk (PAR) estimate for the independent foodborne risk factors in this study was 31%, which is considerably less than the 75% to 80% of cases in the general population which are thought to be caused through foodborne transmission. Possible explanations for these results include the likelihood that a proportion of foodborne transmission in Australia occurs through food vehicles other than chicken due to cross-contamination from raw products, and the likelihood that much of the population attributable risk that is unaccountered for, may in fact be due to inherent limitations of study design resulting in systematic errors (information bias) and possibly reduced estimates of effect. The burden of illness among the general population in Australia attributable to different independent risk factors was estimated using a novel method developed specifically for this study. Briefly, community incidence data was coupled with PAR data from the case-control study and simulation techniques were used to: (i) estimate the number of infections attributable to specific risk factors, and (ii) derive credible intervals for these estimates by modeling the uncertainty in each variable component. This model of using case-control data in conjunction with pre-existing surveillance data provides researchers with a simple but robust tool for conducting source attribution studies on enteric pathogens. In conclusion, the studies undertaken in this thesis have made important contributions to our understanding of the epidemiology of sporadic Campylobacter infection in Australia.

A Study of the Mechanics of Coal Mine Rib Deformation and Rib Support as a basis for Engineering Design.

Colwell, Mark Gerard — 2008-11-21T00:00:00Z

With an increasing focus on safety in the Australian underground coal mining industry and government legislation requiring employers to provide a safe workplace, there is a clear need for today’s strata control engineers to have design capabilities in relation to coal mine rib support that provide effective, reliable and consistent solutions. There has been a relatively limited amount of research undertaken with respect to the study of the mechanics of coal mine rib deformation and rib support and prior to this study no systematic rib support design technique had been developed for any country’s underground coal mining industry. This is in direct contrast to other geotechnical issues, such as coal mine roof support and pillar design, which have been extensively researched resulting in numerous technical papers, conferences/workshops dedicated to these specific issues and several proposed design techniques and/or guidelines. It is assessed that the primary reasons for this disparity have been a lack of understanding concerning the failure mechanisms associated with ribline behaviour and not being able to delineate the significant factors that affect ribline behaviour. This thesis has investigated the mechanical behaviour of coal mine ribs under various loading environments and with a wide variety of rib support hardware as a basis upon which an engineered design methodology could be formulated. A program of full scale field trials were conducted at ten collieries (representing four of the five major Australian coalfields), in conjunction with a comprehensive industry wide review of ribline performance from which a database was formulated and statistically analysed. The results of the field based experimental program and statistical analyses strongly suggest that the mechanical nature of rib movement is consistent with the buckling of thin coal plates or slabs. While a precursor to buckling may be tensile failure in the form of vertical splitting along cleat, mining induced fractures (as a result of roadway development) or the formation of new cracks due to longwall abutment loading; it is clear from the extensometry that the nature and magnitude of the lateral displacement is a result of buckling. There was a significant reduction with respect to the extent of softening within the riblines that utilised areal support in the form of steel or plastic mesh. The major structural or mechanistic benefit of mesh to overall ribline performance is that it maintains the buckled coal plate to the ribline allowing it to behave (to a degree) like a spring, which in this instance not only provides resistance to the vertical stress but also provides an active lateral force to the inner coal plates. Essentially the best rib support in terms of overall roadway maintenance is potentially the rib itself. Based on the results of this study and an improved understanding of the mechanistic behaviour of coal mine ribs, a design methodology (the first of its type), known as Analysis and Design of Rib Support (ADRS), has been developed for the Australian underground coal mining industry. Since its release to the Australian collieries in February/March 2005 via ACARP technology transfer workshops, ADRS has now been registered and successfully used by most Australian collieries, the NSW Mining Inspectorate and several consultants. ADRS is an empirical technique, which recognises that several geotechnical and design factors affect ribline performance and in addition that operational and safety issues essentially dictate the level of performance required. Therefore the design recommendations associated with ADRS are specific to the Australian coal industry; however the procedure(s) for data collection and analysis could be applied to other countries’ underground coal industries.

A study of the membrane interactions of K-ras

Lau, Chiyan — 2008-11-21T00:00:00Z

Ras proteins are monomeric GTPases which operate in cellular signal transduction pathways to regulate cell growth, differentiation and apoptosis. Mutations at amino acid residue 12, 13 or 61 render the protein constitutively active and oncogenic. These mutations are found in 30% of human cancers. There are three isoforms of the Ras protein: H-ras, N-ras and K-ras. All three isoforms localize to the inner leaflet of the plasma membrane, and this localization is important for their biological function. H-ras and N-ras traffic to the plasma membrane via the classical exocytic pathway, while the K-ras trafficking pathway is non-vesicular and is currently poorly characterized. In order to identify the proteins that may be involved in the K-ras trafficking pathway, an affinity chromatography approach was developed. The method utilized the C-terminal membrane-targeting regions of K-ras (CTK) and H-ras (CTH) as baits to purify cellular proteins from mouse brain cytosol. Proteins which selectively interacted with CTK but not CTH were identified by mass spectrometry. Four of these proteins, B23, Ncl, LANCL1 and laminin receptor-1, were further characterized and evaluated as putative K-ras transport factors. B23 localizes to P100 and nuclear fractions, and selectively interacts with K-ras in vivo. However, overexpression or siRNA-mediated knockdown of B23 does not affect plasma membrane localization of K-ras. Ncl localizes to the P100, S100 and nuclear fractions. Nuclear Ncl, but not extranuclear Ncl, selectively interacts with K-ras in vivo. Overexpression of Ncl does not affect the intracellular localization of either H-ras or K-ras. LANCL1 is associated with the P100, S100 and nuclear fractions, and preliminary results show that LANCL1 may selectively interact with K-ras in vivo. Selective interaction between laminin receptor-1 and K-ras could not be confirmed, either in vitro or in vivo. Also, overexpression of laminin receptor-1 has no effect on the P100/S100 distribution of K-ras, or its downstream MEK/ERK signalling. In conclusion, this thesis represents the first known proteomic approach dedicated to the discovery of K-ras transport factors. Three novel selective interacting partners of the membrane targeting domain of K-ras are identified, although their precise function in K-ras trafficking remains to be elucidated.

A study on diffusion and flow of sub-critical hydrocarbons in activated carbon

BAE, Jun-Seok — 2008-11-21T00:00:00Z

This thesis deals with diffusion and flow of sub-critical hydrocarbons in activated carbon by using a differential permeation method. The hydrocarbons are selected according to the effect on environmental concerns and their unique characteristics such as polarity and affinity towards activated carbon. Although it has been known that transport processes in activated carbon consist of Knudsen diffusion, gaseous viscous flow, adsorbed phase diffusion (so called, surface diffusion) and condensate flow, there have been no rigorous models to describe the transport processes in activated carbon with a full range of pressures. In particular among the four processes, the mechanism of adsorbed phase diffusion in activated carbon is still far from complete understanding. Also due to the dispersion interactions between adsorbing molecules and the solid surface, one would expect that Knudsen diffusion is influenced by the dispersive forces. From intensive experimental observations with a great care over a full range of pressures, conventional methods (for example, direct estimation from inert gas experiments) to determine adsorbed phase diffusion are found to be inadequate for strongly adsorbing vapors in activated carbon. By incorporating the effect of adsorbate-adsorbent interactions into Knudsen diffusivity, the general behavior of adsorbed phase diffusion in terms of pressure (or surface loading) can be obtained, showing a significant role in transport at low pressures. For non-polar hydrocarbons such as benzene, carbon tetrachloride and n-hexane, a mathematical model, which accounts for the effects of adsorbate-adsorbent interactions and pore size distribution, is formulated and validated, resulting in a good agreement with experimental data. Moreover, the adsorption and dynamic behaviors of alcohol molecules (which are polar compounds) are investigated with an aim to compare their behaviors against those of non-polar compounds.

Asymmetric Dependence Structures

Anthony Hatherley — 2009-08-28T00:00:00Z

Asymmetric dependence (AD) is defined as dependence that differs across opposing regions of the joint return distribution. Recent evidence of AD between equity returns suggests that dependence can be decomposed into a linear component, captured by the correlation matrix, and a higher order component. When these higher order terms are characterised by increased correlation in bear or bull markets, the effectiveness of diversification strategies is reduced. To the extent that an investor is unable to completely diversify these higher order terms of dependence, it follows that they should be reflected in asset prices and managed explicitly during the portfolio construction process. The aim of this thesis is to determine the extent of AD amongst asset returns, to investigate whether AD is priced and to develop a means of managing AD in the portfolio. I justify the existence of AD and the separation of AD from linear dependence via the bivariate Edgeworth expansion, finding that the joint return distribution may be described by an infinite number of higher order co-moments. Correlation (and hence β) describes one dimension of an infinite number of higher dimensions describing dependence. To determine the importance of AD in finance, I first develop measures that can detect AD independent of the level of linear dependence and idiosyncratic risk. These measures are used to determine the extent of AD amongst US stock returns and the market, to obtain an understanding of how AD changes through time and to re-examine the evidence of AD between equity portfolios. By measuring AD separate from linear dependence, I demonstrate several findings. First, I find evidence of non-stationary AD that can exists irrespective of the magnitude of linear dependence, measured by β. This time-varying AD consists of both significant upper tail dependence (UTD) and significant lower tail dependence (LTD), although LTD is found to occur more frequently than UTD, especially for small stocks and stocks displaying high idiosyncratic risk. Significant time-varying AD is also detected between domestic equity indices and international equity markets, implying that if a portfolio is weighted towards certain industries or countries, portfolio construction methods may need to be adjusted in order too meet risk and return targets, particularly if future AD cannot be adequately forecasted. Next, I investigate whether AD is priced in US equities using the Fama and MacBeth (1973) regression methodology in conjunction with my β invariant AD metrics. I find that AD is as important as linear dependence in explaining the variation in returns. In particular, a positive relationship between LTD and return is found. I document an AD risk premium of 2.7% pa, compared to a β risk premium of 6.18% pa. The AD risk premium increases to 6.9% pa for stocks with significant LTD. This result holds after controlling for size, book-to-market ratio, downside β and coskewness. I also find past AD is a significant variable in predicting the future returns of small firms, whilst neither AD nor linear dependence predict the future returns of large firms. I subsequently demonstrate a means of incorporating AD structures during the portfolio construction process using copula functions. I then investigate how asymmetric return dependencies affect the efficient frontier and subsequent portfolio performance under a dynamic rebalancing framework. By considering the problem of tactically allocating a small set of domestic equity indices, I demonstrate several findings. First, I show that a Mean-Variance efficient frontier differs from the efficient frontier constructed under AD. Constructing paper portfolios based upon these differences, I find that real economic value lies in correctly accounting for AD structures. The primary source of this economic value stems from the ability to better protect portfolio value and reduce the size of any erosion in return relative to the normal portfolio. Finally, I document the benefits of actively managing AD during the portfolio construction process and determine a number of portfolio management principles required to successfully manage AD. I illustrate that managing asymmetry risk in a portfolio of international equity indices results in increased return, decreased risk and decreased transaction costs. I show that in order to yield these benefits, investors must actively and dynamically manage their portfolio. Furthermore, I illustrate that the ability to short-sell assets provides most of the benefits described.

A systems approach to value management and performance improvement: a case study of fresh vegetable supply chains in Nairobi, Kenya

Macharia, John Mwaura — 2012-11-05T00:00:00Z

A systems science analysis of the context/s of child protection reform in Queensland, Australia

Joel Cullin — 2010-05-18T00:00:00Z

A Technological Analysis of a Neolithic Lithic Workshop at Bai Ben, Vietnam

Nguyen, Dong — 2008-11-21T00:00:00Z

This thesis investigates the issue of how stone drill points were manufactured at the Late Neolithic workshop of Bai Ben, Northeastern Vietnam, from a technological perspective, and with the aim of understanding the organisation of technology at the site. Within this organisational approach, the issue is investigated in a comprehensive manner from raw material procurement to drill manufacture, use, maintenance, and discard. Attribute based statistical methods are developed to observe the time-ordering of dimensional and morphological changes of classes of cores and drills with the ultimate aim of reconstructing the reduction sequences so that the position of drill points within these sequences is better identified. The analyses show that raw material used to produce drill points is variable in size as well as locally available and readily accessible in the region. The availability and the variation of raw material size are in turn shown to be key factors that strongly affect the whole process of core reduction at Bai Ben. It can be seen in both freehand and bipolar core populations that there is not a simple single reduction trajectory but a complex reduction process that involves reduction sequences of varying lengths. Raw material of different sizes could be transformed either by first employing freehand percussion followed by bipolar percussion, or by directly employing a bipolar technique. Cores could be discarded at many points along the reduction continuum, creating a complex pattern of core size and reduction intensity. In contrast to core reduction, drill reduction was not substantially influenced by raw material selection, but by the initial size and shape of drill blanks. This determined how much reduction was necessary to create a standardized product. The time-ordering of dimensional and morphological changes in various artefact classes thus permits us to understand the causes of assemblage variability at the site. This research represents the first application of a technological approach to the archaeological record of Vietnam. This study illustrates the benefits of conducting future technological investigations at the numerous other workshop sites known from Vietnam. It is argued that such investigations are required to build an understanding of the nature and importance of specialized lithic activities, trade, and exchange in this period of significant cultural change.

A tectonic dimension: studies of an architectural design methodology

Baber, Kimberley Richard — 2012-11-08T00:00:00Z

A Test Bed for the Development of Eddy Current Inspection Techniques for Non Ferrous Heat Exchangers

Turner, Michael Martyn — 2008-11-21T00:00:00Z

This thesis describes the development and implementation of a test bed for the investigation of eddy current inspection techniques used in the examination of nonferrous heat exchangers found in thermal power stations. This thesis is the product of a research project funded by the Queensland electricity industry and is also the report of its progress. The pressures placed on the environment by the emission of green house gasses and the commercial pressure to decrease the cost of electricity generation has lead to a change in plant inspection philosophy. With the development of nuclear power generation the need for safe reliable operation led to the development of heat exchanger inspection techniques. These techniques placed a priority on guaranteed results with little emphasis on cost. The techniques developed were slow and labour intensive. They were therefor inappropriate for use in non-critical inspections. With the change in environmental policy a move was made within the Queensland electricity industry to develop a cheap effective method to inspect balance of plant heat exchangers in thermal power stations. The development of computer based analysis techniques highlighted basic deficiencies in the theory generally applied to eddy current testing of heat exchangers. This resulted in the commissioning of a project to investigate the process of heat exchanger inspection and develop a more efficient technique to carry out the task. This thesis is the report on the main stream research carried out for this project. The thesis reviews the current techniques available for the inspection of non-ferrous tubing. It covers main stream techniques, as well as specialised and experimental processes. The results of the review indicate that eddy current inspection is still the most appropriate method. A review of the research being undertaken into eddy current inspection was carried out. The review highlighted the pure physics approaches being taken and concluded that their complexity ruled them out for practical implementation. The parametric approaches showed much greater promise and a recommendation for the implementation of some findings was made. The review also highlighted the lack of data for further investigation and indicated the path for the continuation of the project. To enable investigation to be carried out a review of the current state of test instruments was carried out. This review indicated that commercial equipment was unsuitable for research purposes. A design for a modern test instrument was developed using the latest digital concepts and electronics. This equipment allowed data to be collected in its pure form with no black box electronics modifying the raw data. The equipment was prototyped and found to be successful. To enable the accurate collection of data an eddy current probe manipulator was designed. It allows the probe to be manipulated in such a manner as to ensure the probe position and velocity is know and is accurate. The development of an air bearing was carried out to ensure the minimum transmission of mechanical noise to the data being collected. The design of the manipulator was successful for use within the bounds of current standards but will require modification to exceed these standards. To enable the analysis of the electromagnetic effects on defect parameters a technique for the production of artificial defects was developed. Plain defects were designed and a series of defects manufactured. At this point, due to a change in the political climate, the funding for the project was removed. This prevented the implementation of the final stage of data collection and theory development. The thesis then indicated the steps required to bring the project to a fruitful conclusion and those for further development.

A textual analysis of female consciousness in twenty-first Chinese women directors' films

Lara Vanderstaay — 2011-03-02T00:00:00Z

Despite the fact that women directors make films in large numbers in the People’s Republic of China (PRC), they have received little critical attention, often being regarded as being too small in number in comparison to their male colleagues to make their films worthy of study. Further, a considerable part of contemporary film research is concerned with industrial structures and political policies rather than analysis of film as a cultural and gendered text. This thesis therefore seeks to fill a gap in current research by focusing on a textual analysis of certain aspects of gender in films by contemporary Chinese women directors. The thesis examines how key textual elements of narrative, camera shots, costumes and settings contribute to the manifestation of female consciousness in six films made by women directors from the PRC in the early years of the twenty-first century. These elements have been selected because they are commonly recognized by scholars as the key elements into which film can be divided and they are among the most common tools used in similar types of film analysis. The films are divided into three groups according to the film sector of origin (see below). Each film is then examined individually and comparatively as a text in the broadest sense of the word with tentative conclusions drawn about cross-sector differences in the manifestation of female consciousness in film. Female consciousness has its source in feminist theory, however it is seen as being somewhat separate, usually as lacking the latter’s political element. Female consciousness is seen as being more appropriate for this thesis than pure feminist theory, as feminism is controversial in the PRC, being seen as a western concept with little relevance to Chinese women, and indeed most Chinese women film directors do not agree with feminism (Cui 2003: 172). The concept of female consciousness as used in this thesis is drawn from multiple sources, primarily feminist film theory of the British psychoanalytic school first established by theorists such as Johnston ([1973] 1999) and Mulvey ([1975] 2000). In using these theorists, however, I am aware of their limitations and the criticisms of their work by scholars such as Kaplan (1983), hooks (1999) and De Lauretis (1984). In the limited research to date which has been completed on women directors of the PRC, female consciousness has sometimes been used to analyse the films, by scholars such as Dai (1994, 1995, 2002a, 2002b), Feng (2000), Cui (2003) and Li and Xiu (1994). These scholars understand female consciousness as being visible in a text when the text is focused on women and their experiences and allows them to develop their own subjectivity and identity. This is the definition used in this thesis. This thesis identifies three sectors in the contemporary film industry of the PRC although it is in no way intended to be an industrial analysis of the sectors and how they function or are controlled. The first sector is the state run studio sector, in which directors are employees of the state and make films for a specific state studio. The second sector is the mainstream commercial sector, whereby directors work for privately owned film companies. The third sector identified in this thesis is the non-mainstream independent sector, in which directors make films independently of both the state and commercial film studios. Films from all three sectors are screened internationally, although films from the latter two sectors are the most well known outside the PRC. The second sector has only existed since 2001, when the State Administration of Radio Film and Television (SARFT) allowed privately owned companies to make films on their own without needing to collaborate with a state run studio as they had needed to in the past (Reynaud 2003a: 37, Sun and Li 2008: vii). This thesis conducts textual analysis of two films from each of the three sectors. The films from the state studio sector are Shanghai Story (Peng Xiaolian, 2004) from the Shanghai Film Studio and Gone is the One Who Held Me Dearest in the World (Ma Xiaoying, 2002) from the Beijing Film Studio. The mainstream commercial sector films are Baober in Love (Li Shaohong, 2004) and Letter from an Unknown Woman (Xu Jinglei, 2005). The films from the non-mainstream independent sector are Fish and Elephant (Li Yu, 2001) and Conjugation (Emily Tang, 2001). These films have been chosen as they are among the most well known films made by women directors from the three sectors. Analysis using the selected elements of narrative, camera shots, costumes and settings found that they provided evidence of female consciousness being manifested in the six selected films. This manifestation of female consciousness contained important commonalities as well as differences in the films from the three sectors.

A THEORETICAL MODEL OF TRANSCULTURAL PROJECT LEADERSHIP

Victor Sohmen — 2011-04-05T00:00:00Z

Research Objective: The core purpose of this study was to gain a deeper understanding of the nature and characteristics of leadership styles or behaviors that are most suited for successful execution of transcultural projects with multi-ethnic participants. Research Problem: Projects are temporary organizations, and a lack of effective project leadership—an under-researched and less apparent ‘soft’ area of project management—has been cited as a major cause of costly project failure, overriding most organizational factors. Studies often point to interpersonal and behavioral problems as the root causes of project failure. Today, the challenge of project leadership is compounded by cross-cultural factors as projects around the world are being increasingly peppered with multi-ethnic participants. To this end, the overarching research question underpinning this study is: What are the leadership characteristics that compose an effective transcultural project leadership model for leaders of projects as temporary organizations composed of multi-ethnic teams? Theoretical Background: A thorough literature review revealed that there was no single theory that could fully explain the constituents of effective project leadership, specifically in a transcultural environment. This study therefore argued for a need to incorporate the unique characteristics of a fast-paced, time-limited and goal-driven project as a temporary organization with a diversity of cultures. With Bass & Avolio’s (1990) ‘Full Range of Leadership Theory’ (FRLT) as the primary theoretical base—supplemented by cross-cultural, project management, and team dynamics theories—a conceptual model of Transcultural Project Leadership (TPL) was developed, undergirded by six theoretically derived hypotheses. A new Cross-cultural Project Leadership (CPL) framework and associated measurement scale were also crafted in this study. Research Design and Methodology: Commensurate with the multi-disciplinary theoretical underpinnings and complexity of the conceptual TPL model, a multi-method, three-stage research design was adopted. The TPL model was operationalized by the MLQ-5X, as well as the Cross-cultural Project Leadership (CPL), and Project Success Measures (PSM) instruments. A stratified, balanced sample pool of 361 international project practitioners comprising transcultural project managers (PMs; n=213), multi-ethnic team members (TMs; n=94), and managers of international project portfolios (MoPs; n=54) were drawn from around the world and directed to a composite, pre-tested, and web-based MLQ-CPL-PSM survey. The three stages of the study were as follows: • Study I: Interviews of transcultural project personnel to ascertain key cross-cultural project leadership (CPL) framework variables to confirm and supplement evidence of these variables from the organizational, cross-cultural, project management, and team dynamics literature; • Study II: Expert reviews and pre-test by senior academicians and seasoned project practitioners for essential validation of the newly developed Cross-cultural Project Leadership (CPL) survey instrument based on the literature review, and the primary research of Study I; and, • Study III: Survey of PMs, TMs, and MoPs using the composite, web-based MLQ-CPL-PSM instrument; detailed quantitative and qualitative analyses to test the conceptual TPL model and the six hypotheses; post-survey qualitative analysis of interviews of international PMs to enable refinement of the conceptual TPL model and development of a parsimonious theoretical TPL model; crafting of a consolidated TPL measurement instrument culled from the composite MLQ-CPL-PSM instrument and informed by the study findings; and, the proposition of a preliminary Theory of Transcultural Project Leadership (TPL). Results: The results of the research confirmed to various extents the six hypotheses of this three-stage study. Key findings were: (1) Passive-avoidant leadership styles are best avoided in transcultural projects; (2) Contingent-reward-based leadership is ineluctable in transcultural projects; and, (3) Concurrent use of transformational (TF), transactional (TR), and cross-cultural project leadership (CPL) has a cumulative and synergistic ‘augmentation’ effect, precipitating ‘exceptional performance’ by participants of the transcultural project. Contributions, Limitations, and Future Directions: This novel research at the confluence of organizational leadership, cross-cultural management, project management, and team dynamics identified behavioral patterns likely to result in effective transcultural project leadership. It extends the above knowledge to percolate even further into cognate literature—such as, organizational behavior, operations management, and international human resource management. For project practitioners and international managers, this TPL study has yielded ‘best practice’ guidelines for training and evaluation in transcultural project environments. Key limitations of the study included a relatively small sample size, cross-sectional data, and uneven distribution of industries and nationalities. Nonetheless, this research will serve as a springboard for widespread testing and refinement of the nascent theoretical model of TPL in diverse industrial and geographical settings—towards consolidation of a pithy and robust Theory of Transcultural Project Leadership.

Athletic Talent Migration: A Case Study of Australian Football

Benjamin Stevens — 2012-03-07T00:00:00Z

Athletic talent migration has pervaded football throughout the game’s professional history. In Australia the instances of player migration has increased dramatically in the last two decades. This thesis is designed to explore the rate and flow of athletic talent migration in Australian football, and analyse the way in which world football has evolved to establish an environment conducive to player migration. Quantitative results highlight that from 1980 – 1989 the average number of Australian football migrants was 7 players per year increasing to 172 players per year for the period of 2000 – 2009. These migrations place Australian football talent all over the world, with the largest contingent choosing Europe (80%) to forge their football careers. Within Europe, England (27%) is far and away the preferred destination of Australian footballers. World Systems is the theoretical paradigm used to explain the global forces acting on a domestic level that have contributed to this dramatic increase in migration. World-systems theory posits four key areas (1. economic gain, 2. Core-periphery relationship, 3. Division of labour and expansion, 4. Shifts in the loci of accumulation and power), that influence the increase in athletic talent migration. The key concept of core-periphery relationship defines the global football dynamic and through three key historical events, the Bosman case of 1994, the commodification of football and the development of the Champions League, players from peripheral and semi-peripheral nation states have been motivated to migrate to the wealthy European core of world football. Player typologies and the investigation of push/pull factors have also been utilized within this thesis to understand migration at a micro level. These typologies and push/pull factors have been focused on the Australian football context and show the unique factors that influence the Australian football player to migrate. The considerable increase in Australian football player migration attests to significant impact global forces have had on the domestic game.

Atom detection and counting in ultracold gases using photoionisation and ion detection

Tom Campey — 2009-01-12T00:00:00Z

A Transcriptome Atlas of the Developing Mouse Urogenital System

Rathi Thiagarajan — 2012-02-09T00:00:00Z

Organ development is a complex process which involves precise orchestration of multiple cell types across time and space. Understanding of urogenital organ development has benefited from the use of mouse models, as it is ideal for laboratory-based genetic manipulations. Recent advances in highthroughput strategies and genomic technologies have enabled global surveys of the transcriptome, and improved characterization of dynamic gene expression states. Such resources can be used to compile gene expression atlases to obtain information of mRNA levels and localization as a basis to understand cellular fate-decision pathways and networks during development. This thesis describes the temporal and spatial transcriptome atlas of the developing mouse urogenital system, with emphasis on the renal system, as a resource to study the cellular and molecular blueprint required for organogenesis. The analyses that encompass this atlas relied heavily upon resources from the GenitoUrinary Development Molecular Anatomy Project (GUDMAP) from which this thesis stems from. The underlying foundation of this atlas provides the basis to understand what is encoded in the transcriptome during organ development. What are the genes required for dynamic regulation of organ development? What cell-types do they represent? How is their expression controlled? And how do these genes and their transcriptional structure encode the instructions to build complex, multi-cellular organs. The first results chapter describes the integration of microarray profiling to identify genome-wide temporal and spatial markers of ovary and testis during gonad development accompanied by in situ hybridization to validate expression and capture the domain-specific expression patterns exhibited by these genes. The second chapter presents a high-resolution investigation of 11 embryonic kidney subcompartment-specific genes which revealed additional molecularly-defined compartments specific cell types within complex heterogeneous compartments. These ‘anchor genes’ formed the basis to model gene expression networks during tissue ligand-receptor interactions and transcription factors regulating tissue specific expression. The final chapter sets the scene for the next phase of analyses towards the survey of transcriptional complexity driving temporal and spatial regulation of gene expression programs in the embryonic kidney using RNA-sequencing. This study provided the basis to update current gene models of developmental programs to include transcriptional dynamics regulating these processes. Together, the outcomes of this thesis provide a valuable resource of genetic markers that can be formally used for cell lineage tracing to map the fate of each cell type in the developmental history of the genitourinary system and facilitate functional studies through transgenic tools. The transcriptome atlas forms a comprehensive dynamic survey of the developing mouse urogenital system, and represents an important resource for functional studies into organ development which will ultimately lead to strategies for tissue regeneration to treat organ damage and disease.

At-risk boys perceptions of masculinities and resilience

Tilling, Julia — 2008-11-21T00:00:00Z

This thesis will address the need for gender issues and the discourses of power to be explored within resilience frameworks to achieve successful outcomes for at-risk males in intervention programs. Due to the western valorisation of traditional masculinities, the backlash politics debate internationally constrains challenges to the existing gender order within intervention programs. The discussion will deal with the notion of hegemonic masculinities and how boys with behaviour problems act out traditional masculinities to gain a sense of male power. It will focus on the notion of at-riskness, which defines these boys as the new victims of accepted social values and does not address the issues of how men victimise other men from different ethnic, class, and sexual preference minority groups, through violent and aggressive tactics (Connell, 1997). For these boys, exploring the interplay of hegemonic masculinities within society will enable them to move into connecting protective processes/factors within alternative programs and the community. Finally, I make suggestions for the design and implementation of future intervention/preventative programs that will integrate gender construction and resilient protective processes/factors.