http://espace.library.uq.edu.au/ The University of Queensland en Fez http://blogs.law.harvard.edu/tech/rss http://espace.library.uq.edu.au/view/UQ:158704 Business Process Management (or BPM) has emerged recently as one of the most prominent technologies in enterprise systems. Generally, BPM aims to provide business process modelling, enactment, and monitoring. BPM attempts to create general frameworks, which avoid the &quothard-coded&quot approach to application integration. It leverages the logic of business processes in the hands of process stakeholders, by abstracting from the data and application implementation details. However, despite the interest of various parties and the development of the technology, BPM solutions have not always delivered successfully. There reside many challenges and difficulties in BPM, which include the scalability, volatility, autonomy, heterogeneity, reliability, and security issues. A wide range of information technologies has been proposed to respond to these issues, but many limitations and challenges still exist; particularly, providing process support for collaborative business processes that are characterised by autonomous processes, asynchronous business activities, and message-based process communication. This thesis is motivated by the requirement to build a new approach for BPM to tackle the challenges of collaborative processes. We propose to integrate Messaging Oriented Middlewares and Rule-based technology into a new so-called Harmonized Messaging Technology (or HMT). The HMT utilises a messaging mechanism empowered by rules for supporting collaborative business processes. In particular, the HMT is intended to bridge the gap between the communication-oriented approaches and rule-based approaches for process management. The technology considers the abstraction of the process logic and the automation of the process management through an ordered flow of messages. In this thesis, we propose a temporal first-order language, which is called Harmonized Messaging Calculus and forms the formal foundation for rules governing the business process execution in HMT. For verification purpose, we consider the correctness criteria for such HMT rules, which help to avoid inconsistencies and unexpected behaviour in executing HMT process models. In addition, this thesis will present the architecture of the systems, which manage business processes through HMT. The functionality of HMT in process modelling and enactment is also investigated. Finally, the flexibility of HMT process models in supporting the new functionality is discussed. We conclude the thesis with the indication of directions for future work, which focus on the issues related to the deployment of HMT. In particular, we raise issues in design interfaces, analysis tools, audit trail data, transactions support, and security. 2008-11-21T00:00:00Z Ma, Dat http://espace.library.uq.edu.au/view/UQ:259653 Australian organisations are affected, regardless of their will, by technical, economic, political and social challenges. The impact of these challenges is reflected in the increasing number of Australian organisations entering into insolvency appointments: 11,758 (2005), 12,486 (2006), 12,018 (2006), 14,173 (2007), and 14,580 (2009) (ASIC 2010). As a result, organisations from all industries are in constant search for potential mechanisms to assist in their survival. This situation may be why process improvement has been the number one CIO priority in 2006-2009, and why it is expected to still be one of the top priorities by 2012 (Gartner 2009) Business Process Improvement (BPI) is an area that is applicable to all organisations regardless of their size, structure, geographical location, and industry. This research aims to investigate means to achieve higher levels of business process improvement (HLOI) in large, for-profit, Australian organisations. Starting from organisational theories, this research proposes a ten-factor a priori model. Stakeholder Theory, Social Network Analysis, and Organisational Capabilities Theory are primarily used as bases for this research. Two main proposed antecedents of HLOI are explained: aligning the key stakeholders’ requirements, and obtaining specific BPI-based organisational capabilities. This study relies on a combination of qualitative and quantitative research methods, including: a preliminary literature review, 3 existing BPI case studies conducted at another tertiary institution, involving 6 people in a pilot case study and 11 in two main case studies, reviewing 992 papers from the elite IS Basket of 6 journals, involving 12 judges in an expert study, 25 respondents in a pilot survey, and obtaining 144 valid responses in a national survey involving all industries. Results demonstrate that traditionally promoted factors such as Effective Communication, Continuous Top Management Support and Resources Availability have little effect on directly increasing the levels of improvement. Practitioners are seeking to continuously achieve more with less. Aligning key stakeholders’ project-related requirements, improving key stakeholders’ levels of centrality, and creating organisation-specific BPI organisational capabilities were found to have roles in the achievement of HLOI. The implications of the research’s findings can be of value to current practitioners. For instance, finding that centrality is more important than effective communication may suggest that using web-based social network tools such as Facebook by key stakeholders can play a role in improving the level of connectedness and subsequently achieving HLOI. Also knowing that organisational capabilities, and not resources availability, play a significant role in the achievement of HLOI may guide organisations in better utilising their resources in the short-run to develop and nourish BPI capabilities in the long-run. Future research will investigate these findings in other settings. 2011-10-26T16:04:48Z Feras Abou Moghdeb http://espace.library.uq.edu.au/view/UQ:158694 Context information can be defined as information about the situation of a person, place or object. Context-aware systems use context information to adapt their behaviour or the content they provide. The role of context management systems is to store, retrieve and evaluate context information on behalf of context-aware applications. Context management systems store context information in repositories, which can be distributed. This research addressed the problem of disconnections in context-aware systems. Disconnections in a context-aware system may occur because of node mobility, network failures or node failures. A research opportunity lay in improving the robustness of context-aware systems to disconnections. While traditional distributed systems methods of improving robustness in the face of disconnections can be applied to context-aware systems, the additional metadata available to context-aware systems may be leveraged to provide smarter caching algorithms. This research tested the above hypothesis by pursuing research into “smart” caching algorithms for context information. Many modern approaches to building context-aware systems use context models to capture relevant concepts and relationships between these concepts. These models are expressed using a modelling language. For the purposes of this research , we focus on the Context Modelling Language (CML), as it provides specific support for context-aware systems. CML supports sophisticated fact-based context modelling in which facts may be associated with a range of attributes, including its quality, classification as static, profiled, sensed or derived and temporal constraints. This thesis shows how these metadata can be used in conjunction with the inherent relational nature of CML to develop efficient caching algorithms for context information. 2008-11-21T00:00:00Z Anandarajah, Myilone http://espace.library.uq.edu.au/view/UQ:152754 2008-08-20T00:00:00Z Samantha Stehbens http://espace.library.uq.edu.au/view/UQ:261904 Cardiac hypertrophy is an independent risk factor for future morbidity and mortality. Recent investigations have centered on identifying the molecular signaling pathways that regulate cardiomyocyte reactivity that lead to pathologic hypertrophic programs. The calcium sensitive phosphatase calcineurin has been considered to be a potential regulator of cardiomyocyte hypertrophy not only by its phosphatase enzymatic activity but also by its mRNA and protein levels. In this project calcineurin B gene expression level in left ventricular hypertrophic tissue of spontaneously hypertensive rats (SHR) at 5 different time points (neonatal, 2 weeks, 4 weeks, 8 weeks and 12 weeks of age), was compared with levels in normotensive Wistar Kyoto (WKY) rats at the same age groups. A pressure overload cardiac hypertrophy model induced by constriction of the abdominal aorta in WKY rats was also created. Calcineurin B mRNA expression and atrial natriuretic peptide (ANP) mRNA expression were measured after 4 weeks of aortic constriction. Calcineurin B gene expression level in cardiomyocytes was not increased compared to WKY animals. Calcineurin B gene expression level in aortic constricted WKY rats after 4 weeks of pressure overload remained unchanged compared with sham operated WKY rats. Although the results do not exclude activation of the calcineurin-signalling pathway during the development of cardiac hypertrophy there was no increase in mRNA levels in the SHR or pressure overload model during the early stages of hypertrophy development. Regulation by calcineurin may be at a translational level or an alternative signalling pathway may be involved in these animal models. In SHR and WKY rats there was an elevation of calcineurin B mRNA expression in neonatal cardiomyocytes which persisted until 4 weeks of age. Calcineurin may be important for the cardiac morphogenesis during prenatal development. In aortic constricted WKY ANP mRNA levels were increased 4 weeks after application of aortic constriction compared to sham animals. The findings with respect to ANP mRNA are consistent with re-expression of foetal genes in cardiomyocytes associated with pressure overload induced cardiac hypertrophy. There was no activation of calcineurin B mRNA in either a genetic model of cardiac hypertrophy (SHR) or the pressure overload model of cardiac hypertrophy despite the development of cardiac hypertrophy. 2011-11-21T00:00:00Z Ji Fang He http://espace.library.uq.edu.au/view/UQ:291433 2013-02-14T23:39:22Z Wu, Tina Ting Liang http://espace.library.uq.edu.au/view/UQ:206366 Calcium is the major mineral component of milk and is essential for neonatal development. To enrich the milk, calcium must pass from the maternal bloodstream, through mammary epithelial cells, into the alveolar lumen. While calcium extrusion from the epithelial cells is well characterized, no calcium channel or transporter has been identified as the major conduit for calcium to enter the mammary epithelial cell from the bloodstream. A major aim of this thesis was to identify a calcium channel or channels responsible for calcium influx into mammary epithelial cells during lactation. Real time reverse transcription-polymerase chain reaction was used to investigate in vivo expression of calcium channels in the murine mammary gland at the four main stages of mammary gland development. The store-operated calcium channel Orai1 was upregulated during lactation relative to its expression in the nulliparous gland. The classic ORAI1 regulator Stim1 was not similarly overexpressed during lactation, however, its isoform Stim2 was modestly upregulated. HC11 murine mammary cells were used as a model to further investigate the role of STIM2 on calcium handling during lactation. siRNA knockdown of Stim2 reduced both basal and agonist-induced peak cytosolic calcium levels, indicative of its role in calcium regulation. In addition to investigating the role of calcium channels in normal mammary development, their role in breast cancer was examined. Real time reverse transcription-polymerase chain reaction was used to identify calcium channels upregulated in human breast cancer cell lines, relative to non-tumorigenic mammary cell lines. TRPV1, TRPV6, and ORAI1 were upregulated in the breast cancer cell lines. Pharmacological modulation of ORAI1 resulted in modest changes in proliferation, but as there was no specific ORAI1 inhibitor, this effect could not be conclusively attributed to ORAI1 inhibition. siRNA was used to specifically target ORAI1 in three human breast cancer cell lines: MCF-7, MDA-MB-231, and T-47D. siRNA knockdown of ORAI1 was specific and potent, and reduced cell viability and altered calcium handing in all three cell lines. The alterations caused by ORAI1 knock down were not related to the expression of the genes CDK2 and FOS, as these did not change upon ORAI1 knockdown. Data mining was performed using the National Center for Biotechnology Information’s (NCBI’s) expressed sequence tag (EST) database, dbEST, and the Oncomine database. ORAI1 was elevated in estrogen receptor negative breast cancers and in the basal breast cancer molecular subtype, a subtype that has a poor prognosis. Other data suggested that breast cancer cells with high STIM1 and low STIM2 expression also correlated with the basal breast cancer subtype. These data indicate that ORAI and STIM proteins have a role in the physiological process of lactation as well as in the regulation of tumorigenic pathways in the breast, and particular gene expression profiles may be predictors of disease prognosis. 2010-06-25T00:00:00Z Damara McAndrew http://espace.library.uq.edu.au/view/UQ:106950 2007-08-24T00:00:00Z Greer, Ristan M http://espace.library.uq.edu.au/view/UQ:212836 People diagnosed with cancer or undergoing cancer treatment experience a wide range of symptoms. One of the most common symptoms experienced by cancer patients today is cancer-related fatigue. Cancer-related fatigue is a complex condition, recognised as a multidimensional construct and thought to be associated with a cluster of symptoms rather than occurring in isolation. Cancer-related fatigue is distressing and can persist beyond the treatment phase or the disease itself. Current understanding of cancer-related fatigue and its management is limited. Further developing our knowledge of cancer-related fatigue may lead to innovative means of improving the identification, prediction and management of this troublesome symptom. To this end, this thesis aims to: I) identify factors reported to have a relationship with cancer-related fatigue; II) examine the course of cancer-related fatigue during and after radiotherapy; III) determine a method of detecting clinically meaningful change in fatigue; IV) examine whether correlates of fatigue are consistent across all fatigue dimensions or whether each dimension has its own unique pattern of correlates; and, V) develop and trial a group-based educational intervention to target cancer-related fatigue. To address Aim I in this thesis, relevant literature was reviewed to identify factors which potentially influence cancer-related fatigue. Factors identified include underlying medical factors (biomedical mechanisms, disease-related factors, treatment-related factors and comorbid conditions); physical or behavioural factors (poor nutrition, decreased activity, sleep disturbance, pain); psychological factors (anxiety and depression); and sociodemographic factors (social support, employment and education). The range of inter-related factors identified makes cancer-related fatigue a challenging condition to manage. The factors associated with cancer-related fatigue were synthesized into the Fatigue Framework to provide a clinically useful format for health professionals working with people with cancer. The Fatigue Framework was used to guide the remainder of the research into cancer-related fatigue presented in this thesis. This research consists of two main studies; a prospective longitudinal cohort study (to address Aims II, III, IV) and a randomised controlled trial (to address Aim V). The first study in this research examined the factors and effects associated with cancer-related fatigue in a radiotherapy population (n=210). Patients undergoing radiotherapy were recruited for a single-centre prospective longitudinal cohort study. Participants were assessed using a battery of assessments at three time points, at the start of radiotherapy, the end of radiotherapy and six weeks after radiotherapy completion. The results of this study were used to address Aim II, to identify the pattern of fatigue over the course of radiotherapy. The level of fatigue reported was shown to significantly increase from start to the end of radiotherapy and then significantly decrease from the end of radiotherapy to six weeks post-treatment for each subscale of the MFI. The results of this study were also used to address Aim III, to determine a method of detecting clinically meaningful change in fatigue. Whilst there are many tools used to assess cancer-related fatigue, the Multidimensional Fatigue Inventory (MFI) was the assessment chosen for use in this research study and throughout this thesis. The MFI is one of the few fatigue assessments that takes the various clinical dimensions of fatigue into account and has established reliability and validity. However, unlike other fatigue assessments, there were no published minimal clinically important difference (MCID) criteria for its use in cancer populations. MCID criteria determine the smallest change in scores that can be regarded as important, allowing clinicians and researchers to interpret the meaning of changes in patients’ fatigue scores. Determination of the MCID was based on the relationship of MFI scores to four clinically relevant constructs: (1) treatment impact on fatigue, (2) health-related quality of life, (3) performance status and (4) occupational productivity. These constructs were used as external or anchor-based measures to determine a MCID for each sub-scale of the MFI. Multiple MCID criteria were identified through the first study, each from a different perspective based on the anchor-based construct used. However, a two-point reference for each MFI sub-scale was suggested as a generic MCID as it was most consistent across the anchors examined. The MCID criteria validated in this study allow better interpretation of changes in MFI sub-scale scores and allow effect size calculations for determining sample size in future studies. The MFI allows assessment of multiple dimensions of fatigue (general fatigue, physical fatigue, reduced activity, reduced motivation and mental fatigue). Minimal previous research had considered the differential effect of symptom correlates on individual dimensions of fatigue. The data of the prospective cohort study were further utilised to address Aim IV, to determine whether correlates of fatigue were consistent across all dimensions or whether each fatigue dimension had its own unique pattern of correlates. Results indicated that each dimension of fatigue was associated with a different pattern of correlates supporting the concept of multiple dimensions of fatigue. This enhanced understanding of fatigue could be used to guide the development of individually tailored interventions to target specific correlates of fatigue in affected domains, or group interventions to address all relevant fatigue correlates. Because fatigue is associated with multiple symptom correlates, it requires multi-focused symptom management. Education is a commonly recommended fatigue management strategy which can be used to target multiple symptoms simultaneously. There is a lack of information about the content and format used in education programs and the effectiveness of education in managing fatigue. The second study in this thesis addressed Aim V, to develop and trial a group-based educational intervention to target cancer-related fatigue. The study examined a group-based educational intervention (CAN-FIT) targeting cancer-related fatigue in radiotherapy patients. A pilot study of the intervention’s feasibility and acceptability indicated the intervention was acceptable to participants and its operation was feasible. Small modifications to program components were made based on participant feedback. A randomised controlled trial was then conducted to examine effectiveness of the CAN-FIT program and to ascertain the most effective timing for such an educational intervention. The study employed a factorial design and recruited 110 participants. Assessments were conducted at three time points, the start of radiotherapy, the end of radiotherapy and six weeks after the completion of radiotherapy. Results of the randomised controlled trial of CAN-FIT did not show a significant effect of the program on cancer-related fatigue levels, however the pre-radiotherapy education sessions were associated with significant increases in physical activity participation. Furthermore, the study demonstrated the delivery of education prior to radiotherapy was more effective than delivery after radiotherapy. This thesis successfully addresses its stated aims and provides a greater understanding of the concept of cancer-related fatigue. The results more clearly describe the course and correlates of fatigue and their relationship with the dimensions of fatigue. The MCID criteria for the MFI can be used in future research to evaluate outcomes and determine sample size in power calculations. The intervention trialled can be used in clinical practice to provide a low-resource intervention to improve activity levels without any subsequent change in fatigue in radiotherapy patients. Together these studies build upon current knowledge and provide directions for future research to address this difficult symptom. 2010-08-21T00:00:00Z Amanda Purcell http://espace.library.uq.edu.au/view/UQ:187218 ABSTRACT Background Oesophageal cancer has a high mortality; it is the 6th most common cause of death due to cancer worldwide. Of the common subtypes of oesophageal cancer, it is the adenocarcinomas that have been rising rapidly in incidence throughout the western world. The incidence of adenocarcinomas now exceeds the previously common squamous cell carcinoma. These recent changes in the incidence patterns of oesophageal cancer suggests that the environmental risk factors associated with these subtypes differ, and that changes in the prevalence of these exposures over time are the most likely explanation for the observed shifts in the incidence. However, due to its low incidence until a few decades ago, the adenocarcinoma subtype has been less studied compared to squamous cell carcinoma, and the environmental factors associated with this cancer have not been so clearly defined. Smoking and alcohol have been the strongest environmental risk factors reported for oesophageal squamous cell carcinoma (OSCC) whereas for oesophageal adenocarcinoma (OAC), the effect of smoking appears to be weaker, and the evidence for an effect of alcohol is scant and inconsistent. However, epidemiologic studies consistently identify people with frequent symptoms of gastro-oesophageal reflux (GOR) as having the highest risk of OAC, but the effect of GOR on OSCC has been negligible. Furthermore, it has been argued that adenocarcinoma occurring at the gastro-oesophageal junction (GOJAC) may have different aetiology again. Together, these reports suggest the three subtypes of oesophageal cancers (OAC, GOJAC and OSCC) may arise through different mechanisms with different strengths in the impact of risk factors. This thesis investigated the independent associations of smoking, alcohol and gastro-oesophageal reflux on cancers of the oesophagus by considering the possibility of variation in the risks due to differences in the dose effect patterns of various measures such as smoking, alcohol and GOR. Method Data from a population-based case-control study of oesophageal and ovarian cancers in Australia were used. Study participants comprised histologically confirmed cases of OSCC (n=308), OAC (n=367) and GOJAC (n=426) who were frequency matched to 1580 controls from the general population. Exposure history for both cases and controls were derived from health and lifestyle questionnaires. Unconditional multivariate logistic regression was used to calculate the odds ratios and 95% confidence intervals for the risk factors analysed. In addition, generalised additive model with a logit link was also used to explore and present the non-linearity in the dose effect pattern for continuous exposures adjusting for other confounding factors. The effects of two exposures combined on these cancers were assessed by obtaining synergy index. Results Smokers were at significantly higher risk of all three subtypes of oesophageal cancer with the risk greatest for OSCC. The effect of smoking was greater for adenocarcinoma occurring at the gastro-oesophageal junction compared to that of the oesophagus. Of the various measures of smoking, duration was significantly associated with all three subtypes of cancer whereas intensity was associated with only OSCC and GOJAC and the dose effect was non-linear. Time since quitting was associated with a steady decline in risk of all three cancers emphasising the health benefits of quitting among smokers. Alcohol was not associated with OAC or GOJAC but was significantly associated with OSCC among those drinking in excess of 170g/week. The association between alcohol and OSCC was modified by smoking; the association with alcohol was significantly greater among current smokers with effect. Low to moderate wine consumption was associated with significant risk reduction for all three cancers compared to non-drinkers. Increased frequency of GOR symptoms was associated with increased risks of OAC and GOJAC, although the risk of OSCC was constrained to frequent GOR symptoms only. The effect of GOR symptoms were exacerbated by smoking whereas it was weakened by regular NSAID use. Lastly, the sensitivity analysis that assessed the effect of non-participation among controls in the estimated effect of smoking and BMI (the two risk factors most likely to be affected by non-participation) showed a slight overestimation of effect of smoking assuming higher exposure rate among non-participants but not BMI while the effect remained strong and statistically significant. Conclusion Smoking, alcohol and GOR symptoms were the environmental factors strongly associated with all subtypes of oesophageal cancers. However, the dose effect patterns of these exposures varied by cancer subtypes. Smoking and alcohol were the larger contributing factors for OSCC whereas smoking and GOR symptoms had greater impact on OAC and GOJAC. Low to moderate wine consumption and regular NSAID use reduced the risk of all three subtypes significantly. While selection bias may have led to mildly inflated risks for smoking, the effects persisted even when modelled under extreme scenarios of biased participation amongst controls, and there was no evidence that selection bias materially affected the other associations. 2009-11-20T00:00:00Z Pandeya, Nirmala http://espace.library.uq.edu.au/view/UQ:292984 2013-03-07T20:46:42Z Hayes, Linda Marie http://espace.library.uq.edu.au/view/UQ:243185 2011-07-01T00:00:00Z Hegarty, Elwyn E. (Elwyn Elizabeth) http://espace.library.uq.edu.au/view/UQ:106566 2007-08-24T00:00:00Z Martinez, Luis A. http://espace.library.uq.edu.au/view/UQ:157966 Whenever autonomous entities work together to meet each other's needs, there arises the problem of how an entity with a need can find and use entities with the capability to meet that need. This problem is seen in Web service architectures, agent systems, and data integration systems, among others. Solutions have been proposed in each of these fields, but they are all dependent on implementation and interface. Hence all are restricted to their particular field, and all require their participants to conform to certain assumptions about implementation and interface. This failure of support for service autonomy is conceptually unattractive and impractical. In this thesis we show how to describe and matchmake service capabilities and client needs in a way that is implementation and interface independent. The result is a service discovery solution that fully supports the rights of services to choose their own implementation and interface. Our representation is capable of capturing capabilities across a range of service types, from Web services to agents to data sources, while ignoring the implementation and interface details that distinguish them. Thus, our solution unifies these fields for description and discovery purposes, allowing data sources with complex language interfaces to compete against form-based Web services and frame-and-slot agents, for example. Moreover, our solution captures all of the most important aspects of capability, such as: the conceptual meaning and limitations on what a service can achieve; what requests can be expressed through a service's interface, and limitations on what attributes of information a service can return. The provision of an interface independent capability description raises the additional question of how to enable a client to invoke the service to which it has been matched, and correctly interpret the results returned; we solve this by providing an interface description that maps from client objectives onto invocations, and from returned results onto a canonical result format. 2008-11-21T00:00:00Z Devereux, Drew http://espace.library.uq.edu.au/view/UQ:291870 2013-02-21T14:44:32Z Li, Yuezhou http://espace.library.uq.edu.au/view/UQ:245169 Engineered Geothermal Systems (EGS) represent a substantial opportunity to expand the potential for geothermal power worldwide. Conventional geothermal systems use water as a heat extraction fluid, and typically as a working fluid. EGS represent an opportunity to use different heat extraction fluids, of which CO2 is one possibility. In-reservoir performance of CO2 as a geothermal heat extraction fluid is well understood, and CO2-based EGS are predicted to benefit from ease of in-reservoir flow due to the transport properties of CO2. However, there is no understanding of the performance of an integrated CO2-based EGS power plant, and the economic viability of the concept is unknown. This thesis builds on previous works to conduct whole-plant thermodynamic modelling to better understand the technical and economic feasibility of CO2-based EGS. This research includes: process modelling of the entire system; examination of the characteristic behaviour of components of the system; preliminary economic assessment and optimisation of the power plant design and operating parameters; analysis of the potential for condensation of H2O-rich fluids in surface equipment and associated corrosion risks; an evaluation of displacement of initial reservoir fluids; and a qualitative assessment of site selection considerations. This research reveals significant differences in the behaviour of CO2¬ as a geothermal heat extraction fluid compared to H2O. In contrast to water-based geothermal systems, CO2 subsurface flow is predominantly influenced by wellbore flow characteristics: frictional pressure drop in the wellbores is likely to outweigh in-reservoir pressure drop. The increased wellbore friction is due to the lower density of CO2, and the larger mass flow of CO2 necessitated by its lower heat capacity. CO2-based EGS performance is also shown to be much more strongly linked to cooling temperature than water. This is because cooling temperature alters CO2 injection well fluid density and therefore the static pressure change in the injection well. The effect is amplified by including a compressor in the surface plant design, due to the compression work also depending on cooling temperature, and higher compressor outlet pressures further increasing injection well densities. Lower site cooling temperature is shown to be more important than higher geothermal reservoir temperature by a factor of approximately three (on a degree basis). This research also reveals that it is preferable to include a compressor in the surface plant design for both technical and economic reasons. The role of wellbore static pressure change is demonstrated to have substantial effects on the economic performance of different potential geothermal resources: in contrast to traditional water-based systems, CO2-based geothermal performs better with increasing resource depth until a reservoir depth of 2000 to 3000 m is reached. This research also examines the role of mutual miscibility of CO2 and H2O, which is expected to alter operation during displacement by CO2 of water initially in the reservoir. Condensation of a H2O-rich phase from a CO2-rich fluid flow presents a risk to surface equipment, particularly the turbine where it may cause corrosion and erosion. This research demonstrates that condensation is likely in the turbine unless geothermal CO2 is produced at (or dried to) concentrations higher than 94 mol% CO2. A method for estimating the time required to sufficiently dry a geothermal reservoir is presented. For a water-saturated reservoir of typical EGS characteristics, drying times are estimated to be of the order of years. That calculation method also estimates of the quantity of CO2 likely to be retained underground in an EGS, from both storage in porous volume space and fluid losses due to outflow and geochemical reaction. A single doublet used for CO2-based EGS is estimated to retain in the range of 5 to 20 million tonnes of CO2 over a 25 year lifetime. The overall conclusions of this body of research are that CO2-based EGS is technically feasible in that a conception of power generation after dry-out has been presented; it is economically feasible if a source of CO2 is available in that capital costs may be on the order of 6000 USD per kW of capacity; and it is particularly attractive if there is a payment associated with retention of CO2 in the geothermal reservoir, as judged by the relationship between cost of CO2 and levelised cost of electricity. It is best suited to reservoirs with low water-content or suffering high injected fluid loss; which are preferably located where low surface cooling temperatures can be achieved, and at depths of the order of 1500 to 4000 m. 2011-08-09T00:00:00Z Aleks Atrens http://espace.library.uq.edu.au/view/UQ:281869 2012-09-14T00:00:00Z Dawson, Grant Kristofor Wayne http://espace.library.uq.edu.au/view/UQ:255087 Heterotrophic axillary bud outgrowth from sugarcane (Saccharum spp. hybrids) setts was used as a model system to demonstrate that sucrose is a mobilisable carbon source. The outgrowth and subsequent biomass accumulation of axillary buds from two-eye setts of mature sugarcane stalks grown in the dark was used to measure carbon mobilisation from sett internode pith tissue. After 42 days growth 99.0 ± 0.72% of sett internode pith sucrose was depleted and 2.66 ± 0.16g of new tissue accumulated. Comparison with a control treatment in which axillary buds were excised at day zero demonstrated that carbon mobilisation was driven by the accumulation of new biomass. Profiling of soluble carbohydrates (viz. sucrose, glucose and fructose), starch, total soluble protein, total amino nitrogen, free amino acids and total insoluble material showed that the sucrose stored in the sett internode pith was the only available carbon source of sufficient size at day zero for the observed biomass accumulation. Other metabolites mobilised were glucose, fructose and some amino acids, notably isoleucine and leucine that were depleted in shoot treatment setts at day 42. Because sucrose stored in mature stalks (in excess of 40 % of stalk dry weight) can be wholly mobilised to supply carbon for the growth of heterotrophic tissues we propose that sucrose mobilisation requires a net sink-to-source transition that acts in toto within sett internode storage parenchyma. From our data it is proposed that mobilisation of sucrose from culm storage parenchyma requires minimal investment of metabolic resources and that the mechanism of sucrose mobilisation is metabolically neutral. Using magnetic resonance spectroscopy and phloem-specific tracer dyes, strong evidence is provided that sucrose is mobilised from sett storage parenchyma via phloem to the growing shoot tissue. Analysis of enzyme activities involved in sucrose metabolism and glycolysis suggest that sucrose synthase activity is down-regulated due to the effects of sucrose mobilisation. Overall, metabolism in storage parenchyma shifts from futile cycling to a more quiescent state during sucrose mobilisation. Trehalose metabolism in sugarcane was engineered in an attempt to create a significant carbon drain of stored sucrose, to impart value added properties and to enhance abiotic stress tolerance. Two transgenes were introduced to the genome: Trehalose-6-phosphate synthase/phosphatase (TPSP) to increase trehalose biosynthesis and an RNAi transgene specific for trehalase to abrogate trehalose catabolism. Plants phenotypically indistinguishable from the wild type plants were recovered that harboured each transgene singularly but no events of co-integration were observed in a total of 14 transgenic lines recovered after bombardment with both constructs. Soluble carbohydrate content was unaffected. Expression of trehalase was abrogated in many lines due to the RNAi transgene; however, no decrease in trehalase activity was observed. A trehalase inhibitor, sufficient to cease porcine trehalase activity wholly, decreased trehalase activity in sugarcane pith tissue extracts by 80%. Trehalose biosynthesis activity in TPSP lines was elevated compared to RNAi lines and the difference bordered on significance (P = 0.080). A positive correlation between TPSP and trehalase activity was present in RNAi transformants that detectably expressed trehalase (Pearson correlation co-efficient = 0.720, P = 0.107). We discuss the implications for engineering trehalose metabolism in terms of an embryonic lethal phenotype due to altered trehalose metabolism. 2011-10-12T00:00:00Z Brian O'Neill http://espace.library.uq.edu.au/view/UQ:289098 2013-01-15T13:14:41Z Ge, Lei http://espace.library.uq.edu.au/view/UQ:155724 2008-10-14T00:00:00Z Smart, Simon Kane http://espace.library.uq.edu.au/view/UQ:185250 Substantial areas of degraded land need to be restored to provide goods such as fuel wood, timber, as well as ecological services including biodiversity, soil protection and hydrological services. The conventional way to rapidly increase forest cover and attain high timber productivity is to use monoculture timber plantations. Many monoculture plantations, including those involving exotic species, have been successfully used for these various purposes. Although monoculture plantations pose some ecological problems they can be productive and sustainable if they are carefully managed. This thesis has two overall objectives 1) to qualify timber yield, biomass growth and carbon sequestration dynamics (including soil C) in different plantations in Vietnam and from these results propose optimal rotations and management systems to provide sustainable productivity and maximise carbon sequestration in plantations; 2) to evaluate the impacts of different land uses and forest covers on soil properties and fertility in Vietnam. Most of the work was done in plantations of Eucalyptus urophylla, Acacia mangium, Pinus merkusii and in secondary forests and pastures. Two approaches were used for modelling plantation growth and soil C dynamics in plantations. One approach used allometric equations combined with a carbon dynamic model (CO2FIX) and the other used the 3-PG process model. Results from both approaches highlighted the unsustainable consequences of short rotation plantations, particularly those using Eucalyptus urophylla which had negative impacts on soil properties and fertility when managed using short rotations. By contrast, Acacia mangium and Pinus merkusii are better than Eucalyptus urophylla in supplying multiple products and improving soil fertility. At the early stages of their development (the first 20 y), secondary forests and A. mangium plantations did not have different effects on soil properties in five soil types at different locations in Vietnam. Individually, the main effect of forest’s biomass on soil properties was found in both A. mangium plantations and secondary forests, with increasing biomass having a positive impact on key soil properties. Soil types have distinguished characteristics on different soil properties and plantation age and latitude have significant impacts on some soil properties. There is a need for a system of long-term permanent plots established over a wider scale for future studies. Such a system would be preferable to the pair-wise comparisons that had to be used in this work. Future researchers should pay attention to the establishment of these permanent plots as the data collected from such system will be extremely valuable to understand ecological dynamics and interactions between vegetation and soil nutrients. 2009-10-27T00:00:00Z Sang Phan http://espace.library.uq.edu.au/view/UQ:158510 The recent rapid decline in tropical and subtropical forests and subsequent loss of biodiversity, coupled to the threat posed by climate change, has led to a requirement for sustainable forest systems. Large-scale monocultures supply timber that can no longer be harvested in sufficient quantity from natural forests in subtropical and tropical regions. However, there is a general perception that forest systems need to be managed to provide multiple production and environmental services, including carbon (C) sequestration, restoration of soil fertility, and biodiversity. Overall, traditional plantation monocultures cannot meet all of these new objectives, and native and mixed-species plantations may provide an alternative, when provision of ecosystem services, besides timber, becomes a priority. The objective of this thesis was twofold. Firstly to assess C storage in native rainforest tree (hoop pine, Araucaria cunninghamii) plantations, planted as monocultures in subtropical Australia. Plantations were examined to evaluate their potential as a sustainable forest system for provision of high-value timber products and C sinks. The second objective was to contrast the traditional monoculture system with a multi-species system, and a mixed-species rainforest tree plantation was studied. These systems are receiving substantial attention from private forest growers as they could provide economic benefits, including greater productivity, coupled to biologically desirable outcomes, such as higher biodiversity. The focus of the second objective was to improve the design of mixtures for maximum wood production and C sequestration, so that other ecological benefits could be realised. Subtropical native hoop pine monocultures did not store soil C into long-term storage pools as rapidly as adjacent native rainforest or pastures. In addition, substantial amounts of soil nitrogen were lost from tree plantations, indicating that with current management, these systems may not be sustainable in the long-term. Overall, total C storage, including soil and aboveground biomass C, was higher in tree plantations than pastures highlighting the potential of native tree plantations for C sequestration. The mechanisms behind lower soil C storage of native hoop pine plantations, compared with rainforest and pasture, may be related to differences in soil C stabilization. While native forest and pasture systems stored C within soil aggregates and through organo-mineral interactions, tree plantations did not show a strong aggregate hierarchy and most soil C was associated with mineral-sized particles. Because soil minerals have a limited capacity to adsorb soil organic C, they may limit the C storage capacity of the studied tree plantations. We conclude that changes to management of hoop pine monocultures, such as increasing plant diversity in tree plantations, may create conditions similar to the native forest and promote greater C sequestration in plantation soils by stabilization through both soil aggregation and organomineral interactions. Since traditional monoculture forest production systems may not provide the multiple benefits needed for sustainable forestry, an alternative mixed-species tree plantation was investigated. We examined the dominant paradigm that mixtures of two fast growing species (Grevillea robusta and Elaeocarpus angustifolius) compete for site resources, while mixtures of shade tolerant (Castanospermum australe) and shade intolerant (G. robusta or E. angustifolius) species are complementary. Contrary to predictions, there was evidence for complementary interactions between the fast-growing species in terms of nutrient uptake, nutrient use efficiency and nutrient cycling. Preliminary model simulations of interactions between species for light indicated that G. robusta maintained the highest rates of photosynthesis under different light conditions and may be combined with C. australe and the more light demanding E. angustifolius in mixtures. Overall there was evidence for tree species combinations which could potentially sequester more C, in addition to other benefits including higher biodiversity and improved use of soil resources, in mixed-species plantations. Such knowledge is useful to encourage implementation of these new timber production systems. 2008-11-21T00:00:00Z Richards, Anna Elizabeth http://espace.library.uq.edu.au/view/UQ:158790 Although inorganic arsenic is classified as a human carcinogen, lack of an appropriate animal model till recently made it difficult to understand the mechanism of its carcinogenicity. The first inorganic arsenic-induced tumour study was reported by Ng et al. (1998) in C57Bl/6J mice exposed to 500 μg/L sodium arsenate in drinking water. Subsequently, Waalkes et al. (2003) demonstrated arsenite as a transplacental carcinogen in C3H mice exposed to 42.5 or 85 mg/L sodium arsenite between the 8th to 18th days of gestation. Recently monomethylarsonous acid (MMAIII), an intermediate metabolite of the arsenic methylation pathway was shown to be more acutely toxic and genotoxic in both in vitro and in vivo studies. However, its carcinogenic effect was unknown. The first aim of the present study is to investigate whether MMAIII was carcinogenic in a mouse model. The second aim was to investigate whether there was a difference between the spontaneous tumour seen in the controls and arsenic induced tumour which occurred in the test. The third aim was to confirm the carcinogenic effects reported by Ng et al. (1998) by exposing mice to three different concentrations of sodium arsenate (AsV) or Monomethylarsonous acid (MMAIII) in drinking water and to establish a dose response relationship for both arsenate and MMAIII in this mouse strain; and finally to investigate if porphyrin profile can be used as an early warning biomarker for chronic arsenic exposure prior to the onset of carcinogenesis. Female C57Bl/6J mice were exposed to drinking water containing AsV (sodium arsenate) or MMAIII (monomethylarsonous acid) at 0,100, 250 and 500 μg/L ad libitum respectively for two years. 24 hrs pooled urine samples were collected every 2 months for urinary arsenic and porphyrin analyses. Dimethylarsinic acid (DMAV) was found to be a major urinary metabolite in both AsV and MMAIII-treated mice. The study confirmed the carcinogenic effects of AsV in this mouse strain and for the first time, demonstrated MMAIII to be similarly carcinogenic. Significant increases in the level of urinary prophyrins were observed in both AsV and MMAIII-treated mice compared to the control group. Histological examination of tumour masses and tumour bearing organs showed lymphoma was the major type of tumour observed in both control and treated groups. Tumours generally occurred 18 months post treatment. Tumour-bearing animals appeared to remain healthy until the terminal stages of the experiment. The increased incidences of lymphomas were dose dependent for both AsV and MMAIII -treated groups. Other types of tumours and multiplicity of tumours also showed a significant dose response relationship in the AsVtreated groups. Mesenteric lymph node lymphoma and metastatic lymphoma in the liver showed significant dose response relationship in MMAIII-treated mice. The incidence of other types of tumours histiocytic sarcoma was higher in both AsV and MMAIII-treated mice compared to the controls. Plasmacytoid lymphomas were observed only in treated mice. Chronic dermatitis and other degenerative skin lesions were seen only in the AsV and MMAIII-treated mice and not in the control. Keratoacanthoma of the skin, epidermoid carcinoma and rhabdomyosarcoma were only seen in the MMAIII treated mice and not in the AsV-treated mice. Immunohistological examination showed the lymphomas to be of B cell origin. Microarray was performed in selected tumour and non-tumour liver tissues from control, 100 and 500 μg/L groups from both AsV and MMAIII-treated animals. Oncogenes, genes involved in cell division and cell proliferation, chemokines, cyclin dependent kinases, tumour necrosis factor genes (TNF), Mitogen activated protein kinase (MAPK) family genes, Signal transducer and activator of transcription (STAT) family genes and DNA damage genes were highly expressed in the MMAIII-treated groups compared to the control group. Genes involved in the Nuclear factor of kappa light chain gene enhancer in B-cells (NFκB) signaling pathway like TNF receptorassociated factor (TRAF), IκBKβ, TRAF family member-associated NF-kappa B activator (TANK) and B-cell leukemia/lymphoma 2 (BCL2) showed more than 32 fold increases in the MMAIII-treated tumours compared to the control tumours. Also inflammatory and B-cell leukaemia and lymphoma genes were expressed in MMAIIItreated tumours only. Genes expressed in the MMAIII-treated tumours showed interesting pathways, the antiapoptotic signaling mediated by the TNF-α induced AKT pathway and prosurvival pathway by TNF-α induced TRAF1 and TRAF2 mediated NFκB activation. The present study is the first low dose chronic study of MMAIII, and both AsV and MMAIII demonstrated to be carcinogenic in C57Bl/6J female mice. Higher incidences of all types of tumours in MMAIII-treated mice and incidences of various types of tumours only in MMAIII-treated groups suggested that MMAIII could be more carcinogenic in vivo than AsV. MMAIII also appeared to have induced a greater variety of genes involved in tumorigenesis compared to AsV. In conclusion, this study supports the contention that the arsenic methylation pathway is not necessarily a detoxification pathway but may in fact in some circumstances enhance the toxicity of the element, and that MMAIII might play a significant role in mammalian arsenic carcinogenicity. 2008-11-21T00:00:00Z Krishnamohan, Manonmanii http://espace.library.uq.edu.au/view/UQ:283561 2012-10-18T00:00:00Z Chan, Vincent W http://espace.library.uq.edu.au/view/UQ:267100 2012-02-07T00:00:00Z Fenning, Andrew S. http://espace.library.uq.edu.au/view/UQ:283050 2012-10-09T00:00:00Z Ma, Yi http://espace.library.uq.edu.au/view/UQ:134442 Coronary heart disease is the single greatest contributor to mortality within developed countries in our time. Type 2 diabetes mellitus and obesity, both of which are potent risk factors for coronary heart disease, are common conditions with rapidly rising rates of prevalence both globally and in Australia. Within Australia, Indigenous Australians suffer from disproportionately high rates of diabetes, obesity and coronary heart disease, the reason for which lies, in part, with changes in dietary intake and decreased levels of physical activity over the past 200 years. These disease trends have led to a substantially reduced life expectancy from an increase in excess cardiovascular deaths in Indigenous Australians. Assessment of cardiovascular risk in Indigenous Australians is complicated by ethnic differences in cardiovascular risk factors and their prevalence. There is also evidence that Indigenous Australians are genetically predisposed to diabetes. Current cardiovascular risk stratification algorithms are suboptimal, significantly underestimating risk in Indigenous Australians. This thesis aimed to address these issues. Firstly, to evaluate the efficacy of a lifestyle intervention programme to sustainably improve markers of health outcome in a cohort of Indigenous Australians who were overweight or had type 2 diabetes mellitus by improving diet and physical activity levels. Secondly, to evaluate the utility of anthropometric markers of obesity, ultrasound markers of atherosclerotic burden and serum C-reactive protein as additional cardiovascular risk stratification tools. The Healthy Lifestyle Programme (HELP) was a two year prospective intervention study designed and implemented with substantial input from the Indigenous community. The primary intervention consisted of a series of educational workshops delivered predominantly by Indigenous health workers advocating improving diet and increasing physical activity. To complement these workshops, facilities were established within the community to support dietary improvement and increased physical activity. Sustainable changes to markers of cardiovascular outcome, including significant reductions in central obesity and blood pressure were demonstrated over time. A slowing in the deterioration of renal function as marked by albuminuria was also detected. These beneficial changes were accompanied by increased physical activity and improved dietary intake. In a substudy, individuals with the apolipoprotein E4 genotype, who were dyslipidaemic at baseline, benefited from lipid profiles that improved significantly during the course of the study. Changes in blood pressure and central obesity detected during the course of the project are likely to have significant clinical impact on health outcomes considering their sustained nature. Evaluating ultrasound imaging based markers of cardiovascular risk, carotid artery intimal medial thickness was a more reliable measure of risk based on its firm correlation with established cardiovascular risk factors compared to brachial artery flow mediated vasodilatation. Carotid artery intimal medial thickness may be the better surrogate marker to improve cardiovascular risk stratification in the Indigenous population. Examining anthropometric markers of obesity, body mass index and waist circumference but not waist hip ratio correlated well with traditional cardiovascular risk factors. Furthermore, both body mass index and waist circumference predicted insulin resistance fairly well using threshold values derived from receiver operating characteristics curve analyses. Both body mass index and waist circumference were simple to perform with a high degree of reproducibility between observers and will likely be valuable additional cardiovascular risk stratification tools. Raised inflammatory stress, as marked by elevated serum C-reactive protein levels, was found in individuals with diabetes or obesity. C-reactive protein levels did not correlate with carotid artery intimal medial thickness, suggesting that C-reactive protein raises cardiovascular risk by means other than increasing atherosclerotic burden. Genotyping a small random sample of our the C-reactive protein gene promoter region. This SNP was found to independently increase serum C-reactive protein in the Framingham cohort. A genetic basis for increased inflammatory stress may contribute to coronary heart disease in Indigenous Australians. In summary, a community centred lifestyle intervention programme was efficacious in producing sustainable improvement in markers of health outcome. Examination of additional cardiovascular risk markers in the Indigenous community have provided evidence for using carotid artery intimal medial thickness, waist circumference, body mass index and serum C-reactive protein levels to improve cardiovascular risk stratification. These additional tools would allow for more specific resource allocation to target individuals at highest cardiovascular risk for preventative management. C-reactive protein gene polymorphisms, their contribution to circulating C-reactive protein levels and cardiovascular outcomes warrants further investigation in the Indigenous population. A more proactive risk management plan, which includes a lifestyle intervention component, may yield the greatest improvement in long term health outcomes if targeted at younger members of the Indigenous community. 2008-04-03T00:00:00Z Chan, Lionel C. K. http://espace.library.uq.edu.au/view/UQ:206303 The purpose of this study was to investigate the attributes and experiences that are perceived priorities for recruitment to become a high performance coach in the sport of Softball in Australia. The study was undertaken in the form of 10 cases of nationally identified coaches and administrators (men and women). Each participant was interviewed using semi-structured questions. The interpretive study gave an intensive description and analysis of coach experiences, attributes and qualifications that are perceived as highly desirable for coach selection by Softball Australia for high performance coaches. The basis for collection and analysis of information was via individual cognitive perspectives and perceptions (through interviews) and individual behaviours (through observation) with the intention to interpret and consider the presence of common themes. Findings may serve to identify, support and direct potential high performance coaches and contribute to the effectiveness of formal coaching education programs. The study focused on the sport of softball which has had a mixed profile over time, from one of almost obscurity to that of an Olympic sport. Australia has had an extremely impressive record internationally. It is currently ranked as the world’s best softball nation based on international performances by the Australian under 19 Men, Open Men, under 19 Women and Open Women’s Teams (SA 2008). Australia was the only country ranked in the top three in all age groups competing in World Championships. The importance of this study to softball coaches was to encapsulate the reality of how selectors make determination on performance coaching selections, and was this in line with what performance coaches perceive as the priorities. This may have two direct effects on the performance coach. Firstly, it may allow the coach to develop a career path that may best suit their qualities and attributes. Secondly, it may allow the coach to undertake further learning and development in the areas that the selectors perceive the coach does not meet the required standard of merit. 2010-06-21T00:00:00Z Kathryn Horton http://espace.library.uq.edu.au/view/UQ:199628 Abstract The majority of young Australian women aspire to be married with at least one child and in some form of paid employment by the time they are 35 years of age. In an age of increasing female labour force participation, it seems then that young women really can have it all. However, while younger generations of women are now more likely than their male counterparts to go to university, Australian women, compared to women in other countries, have low workforce participation rates after childbearing; and many move to part-time positions characterised by lower earnings, less responsibility and less opportunity for training and promotion. Further, there continues to be significant occupational segregation in the workplace, and women continue to earn significantly less than men. Why are Australian women not utilizing their skills to their full potential? The issue of balancing paid work with family responsibilities is central to this debate; and crucial is the role of Australian work-family legislation, which has previously focussed on improving Australia’s low fertility rate through financial aids rather than recognising women’s increased attachment to the paid workforce. This underscores the need for further research on how young Australian women negotiate work and family, to contribute to the evidence base for the formation of policy that supports the needs of young Australian women. This thesis takes an innovative approach of examining the work and family aspirations of a new generation of young Australian women negotiating work and family, transitioning from their late teens/early twenties to their early 30s. A prominent theoretical model of women’s work and family preferences, Lifestyle Preference Theory, postulates that women’s work and family outcomes are primarily the result of what they had always aspired, and that all women living in contemporary society can ‘choose’ their preferred type of lifestyle. However, as argued in this thesis, this model doesn’t take into account women’s circumstances, systemic-level supports and life changes that impact upon women’s decisions. Further, compared to previous generations of women, when most of the research on women’s aspirations was conducted, there is a new development process bridging adolescence and early adulthood, termed Emerging Adulthood. Using a mixed-methods approach of quantitative and qualitative analyses, this thesis examines young Australian women’s work and family aspirations according to their life experiences and within the social and structural constraints on their lives, during this developmental period of the life course and new socio-historical context. Chapter 1 provides a historical context to women’s changing roles and increasing workforce participation over past decades, while also discussing the pervasiveness of gender stereotypes and gender differences in the workforce. Chapter 2 discusses the Australian context in more depth; including work and family trends and systemic-level work-family support. This section also introduces theoretical contributions in the area of women’s aspirations, and developmental changes likely to affect young women. Chapter 3 then provides an analysis of young Australian women’s work and family aspirations, including the consistency of their aspirations over time, using nationally representative data from the younger cohort of the Australian Longitudinal Study on Women’s Health (ALSWH). Chapters 4 and 5 examine the representativeness of Lifestyle Preference Theory as a model of young Australian women’s work and family aspirations. Chapter 4 investigates whether Australian women can be categorised as ‘types’ committed to pursuing a particular lifestyle while Chapter 5 investigates whether women’s aspirations are independent of context, as theorised by Lifestyle Preference Theory, or correlated to women’s circumstances and the constraints on their lives. Chapters 6 and 7 aim to give voices to the experiences of young Australian women forming their aspirations during this period of the lifespan, by analysing qualitative comments from the younger cohort of the ALSWH. Chapter 6 provides a context of what is important and happening in the lives of young Australian women, while Chapter 7 provides a more thorough discussion of women’s comments about their aspirations and with a comparative discussion of their comments to current theoretical models. Through an analysis of focus group material, Chapter 8 continues to examine the experiences of young women during this developmental period of the lifespan. This Chapter reviews young women’s thoughts on their aspirations for work and family, how they anticipate making work and family decisions, and how they perceive and experience this developmental period of the lifespan. Chapters 9 and 10 return to the quantitative data of the ALSWH to investigate why women change their aspirations over time, and specifically look at the impact of first birth and life events on women’s motherhood and employment aspirations. These Chapters discuss the role of systemic-level work-family support on women’s changing aspirations. Chapter 11 provides an integrative conclusion of findings, which show that women are forming and adjusting their aspirations as best they can within their circumstances and the constraints on their lives, and the broader context of Australia’s work and family support systems. This Chapter provides recommendations for policy and directions for future research. 2010-03-17T00:00:00Z Melissa Johnstone http://espace.library.uq.edu.au/view/UQ:273732 This study investigates the effect of uncertainty on professionals’ careers. Rapid socioeconomic changes in society, the labour market and organisations have resulted in increased instability and uncertainty in the environment in which people construct their career. Identifiable career paths can no longer be expected as organisational, occupational, and geographic boundaries become increasingly permeable. Moreover, as traditional objective markers of success such as pay and status decline in prominence, career success is increasingly defined by subjective measures, which themselves are uncertain. Professional careers are particularly uncertain. A wide variety of career structures are available to professionals, configurations in which they form and enact multiple identities, and the threat of knowledge obsolescence is ever-present. Despite the increased uncertainty in professional careers, uncertainty has not been systematically investigated. Traditional matching (Holland, 1959; Parsons, 1909) and developmental process career theories (Gottfredson, 1981; Super, 1984) retain a strong presence the field yet overlook the effect of uncertainty. Some contemporary career theories acknowledge uncertainty in, for example, the context within which careers are enacted (e.g. Arthur & Rousseau, 1996c), in the process of constructing a career (e.g. Lent, 2005) or within an individual’s subjective career (e.g. Khapova, Arthur, & Wilderom, 2006). However, none problematise uncertainty, implicitly suggesting that it has the same meaning for all people. These shortcomings are addressed in this thesis by investigating how the meaning that people ascribe to uncertainty affects their career? The study used an interpretive research design and a narrative approach. Twenty in-depth interviews with professionals yielded rich data of people’s experiences of uncertainty in their career and the meaning that they ascribed to these uncertainties. The empirical results identified four distinct genres of career uncertainty: Stabiliser, Glider, Energiser and Adventurer. Each genre represents a distinct understanding of uncertainty – a shared meaning – that differs from personality traits or attitudes. Moreover, the variation of understanding of uncertainty affects career behaviour in distinctive ways, notably, in how people make career decisions, form and maintain a working identity, achieve career success and find meaning in work, structure their career, respond to job insecurity, display individual agency, and develop a clear self-concept. Together these behaviours led to the identification of an uncertainty based-framework for career theory that represents a continuum of understanding of uncertainty from negative to positive. The framework challenges the dominant logic of uncertainty in existing career theory in two important ways. First, the framework shows that uncertainty affects the behaviours through which people construct, enact and experience their career. The findings support and extend career theories that acknowledge the role of uncertainty in people’s career, while challenging the matching and developmental process theories that overlook uncertainty. Second, the uncertainty-based framework proposes that people have different understandings of uncertainty which affects their career behaviour in distinct ways. Thus, the contribution is a more nuanced understanding of the nature and role that uncertainty plays in career construction. Implications exist for people who confront uncertainty as well as the career counsellors who support them. The results also narrow the gap between theory and practice and suggest future research directions. 2012-05-07T00:00:00Z Trevor-Roberts, Edwin http://espace.library.uq.edu.au/view/UQ:287545 2012-12-19T13:22:18Z Jaramillo-Ferrada, Pamela Alejandra http://espace.library.uq.edu.au/view/UQ:106369 2007-08-24T00:00:00Z Mitchell, Peta Robyn http://espace.library.uq.edu.au/view/UQ:252064 Baz Kershaw argues that theatre buildings are embedded within a “disciplinary system” that traps audiences within an “unfair system of privilege” through commodification, cultural policy, and spatial indoctrination that act as “mechanisms of exclusion” (31). By escaping the theatre building, however, site-specific performance is able to seek new audiences by engaging with alternative, more accessible locations. Recent Australian productions suggest that found space performances are not always motivated by the same political objectives of their site-specific forbears. I argue that found space performance constitutes a separate category of inquiry that requires a deeper analysis of the interaction between space and performance in the absence of a profound engagement with site. I use Henri Lefebvre’s theory of the production of space to investigate how the site prescribes behaviour for actors and spectators even when the performance is in an unconventional location. Analysing found space performance through the lens of Lefebvre’s triad reveals how space conditions the production and reception of theatre even when it is removed from the purpose-built building. This thesis provides a model of how to analyse performance through Lefebvre’s triad—spatial practices, representations of space, and representational space—in order to determine whether case performances merely capitulate to the existing power relations of the site, or whether, in fact, they disrupt the disciplinary forces and succeed in creating counter-space. Case studies for this thesis were selected from local Brisbane performances and international arts festival productions in other Australian capital cities between 2008 and 2010. They were all performed in unconventional locations including the steps of the Convention Centre outside BHP Billiton’s 2009 Annual General Meeting for a performance protest by Gorilla Street Theatre, the grounds of Brisbane’s Old Museum for Zen Zen Zo’s Dante’s Inferno, a bus for Cocoloco’s The Alice and Alice Bus Tour, a supermarket for Rotozaza’s Wondermart, the grounds of a former institution for Urban Theatre Project’s The Fence, and a suburban house for Still the Monster’s Up All Night. A Lefebvrian reading of these performances reveals how the spatial practices of the site interact with theatrical conventions to guide audience reception and participation, how the socio-political history of the site as a representation of space can overwhelm the reading of the performance, and finally how the imaginative overlaying of representational spaces proscribes our behaviour in those spaces. Exploring Lefebvre’s triad through performance elucidates how each element operates within the urban environment and ultimately determines whether theatrical performances produce counter-space. Theatre as a spatial medium is uniquely positioned to produce alternative counter-spaces through the live, embodied act of performance. Performing outside of the purpose-built building should enable practitioners to negate the commodification, cultural policy, and spatial indoctrination of mainstream theatre and to produce alternative spaces. These case studies reveal, however, that this potential is often not achieved by found space performance. For theatre in found space to be politically effective and to produce counter-space, artists must first be aware of how the space (and the performance in that space) is produced and then work actively to reveal and intervene into the power relations at the performance location. Reading found space performance through Lefebvre’s spatial triad reveals the inherently spatial nature of theatre and how it is imbricated within the production of space. Working in unconventional locations offers artists an opportunity to expand beyond the theatre building to not only offer spectators a unique and accessible experience, but if used to their potential, to intervene in the existing power relations of the site and to create alternative spaces. 2011-09-16T00:00:00Z Sarah Thomasson http://espace.library.uq.edu.au/view/UQ:157849 Catalyst deactivation in single catalyst pellets and in an isothermal catalytic fixed bed reactor have been analytically studied. The work reported here is unlike the vast majority of previous theoretical analyses which are numerical. This thesis deals with two types of deactivation - parallel and series mechanisms in which respectively, reactant and product are directly responsible for poisoning. For the single particle studies, the principal analytical tools used are based on singular perturbation theory. Use of these techniques in the temporal domain depends crucially on the smallness of the ratio of the deactivation rate constant to that of the main reaction. Depending on the range of Thiele modulus, whether small, intermediate or large, three different techniques are used in the spatial domain. First, when the Thiele modulus is small, a lumping technique due to Frank-Kamentskii (1955) is used to replace the Laplacian operator by a suitable constant. This reduces the coupled partial differential equations to ordinary ones. Main chemical kinetics of n-th order and of Michaelis-Menten type are investigated. Second, when the Thiele modulus is very large, matched asymptotic expansions in the spatial domain are used. The analysis is based on the smallness of the inverse Thiele modulus, 1/phi2. A moving reaction zone of thickness 0(1/phi) is found to separate the dead shell from the active core of the catalyst pellet. The catalyst activity profile exhibits a sharp change within the reaction zone and the structure of this profile is found to be self-preserving during the period of its propagation. Solutions are obtained for three different geometries - planar, cylindrical and spherical. The large Thiele modulus results obtained here are found to be more accurate than the shell-model solutions of Masamune and Smith (1966) (except for a slab geometry, when they are identical). Finally, for an intermediate range of Thiele modulus, finite Sturm-Liouville integral transforms along with the concept of an effective average are successfully applied. The approach taken is novel, and although not rigorously justifiable, it leads to results of suprising accuracy. The versatility of the technique is demonstrated by application to various non-linear problems which posess exact solutions and remarkable agreement is found. The finite-cylindrical catalyst pellet is also investigated using a double-integral transform in the spatial domain and it is shown that for small Thiele modulus, the infinite cylinder and slab results are good approximations to finite length cylinders with small and large ratio, R/L, respectively. The analytical solutions reported in this thesis agree well with the known numerical results of others (Masamune and Smith, 1966; Khang and Levenspiel, 1973 and Lamba and Dudukovic, 1978). The parametric - dependence of these solutions is explicit and numerical results can be easily obtained from them by hand calculation. All the single pellet results are brought together in the final chapter and used to analyze the performance of isothermal fixed-bed reactors undergoing poisoning. Such effects as external mass transfer resistance, pellet shape and chemical kinetic type are included in the analysis, which embraces the entire range of Thiele modulus. 2008-11-21T00:00:00Z Do, Duong Dang http://espace.library.uq.edu.au/view/UQ:164059 Chronic anthropogenic disturbance has left many marine systems at risk of degrading into undesirable states. In many cases, ecosystem shifts are triggered by catastrophic disturbance events that are beyond the control of local management, such as coral bleaching or cyclones. Recognition of this risk has instigated what has been referred to as a new paradigm for marine stewardship; managing areas with the explicit goal of maintaining ecosystem resilience. Despite this, there has been little synthetic influence of resilience theory on marine conservation planning. This thesis focuses on how to make good decisions regarding the selection of marine protected areas (MPAs), in the face of catastrophic disturbance events and for the conservation of highly dynamic marine systems. Large-scale catastrophic events, although rare, lie generally beyond the control of local management and can prevent marine reserves from achieving biodiversity outcomes. In Chapter 2, I formulate a new conservation planning problem that aims to minimize the probability of missing marine conservation targets as result of catastrophic events. To illustrate this approach, I address the problem of minimizing the impact of large scale coral bleaching events on a reserve system for the Great Barrier Reef, Australia. By explicitly considering the threat of catastrophic bleaching as part of the reserve design problem, it was possible to substantially improve the likely persistence of coral reefs within reserve networks, for a negligible increase in reserve cost. The results also demonstrate that simply aiming to protect the reefs at lowest risk of catastrophic bleaching does not necessarily lead to the best conservation outcomes. It is thought that recovery of marine habitats from uncontrollable disturbance may be faster in marine reserves than in unprotected habitats. But which marine habitats should be protected, those areas at greatest risk or those at least risk? In Chapter 3, I define this problem mathematically for two alternate conservation objectives and determine under which conditions each of the different protection strategies are optimal. With regard to the risk of uncontrollable disturbance, the optimal protection strategy depends on both the conservation objective and the expected rate of habitat recovery inside and outside protected areas. I illustrate this decision making with an example of cyclone disturbance of coral reefs on Australia’s Great Barrier Reef. An adequate consideration of risk can indicate surprising routes to conservation success. The resilience of coral reef systems is closely linked to the presence of grazing herbivores. Although herbivore populations are generally protected through permanent static reserves, the benefits of protection are dynamic in both time and space. Periodically moving protection between reefs allows access to the greatest potential benefits of reservation and can help address social reluctance to permanently close areas. Using analytic methods to solve a theoretical case study, I demonstrate that periodically rotating protection around a reef system can lead to greater average reef resilience than under static protection, but only if the overall level of reservation is high enough or the rotation does not include all reefs in the system. The past ten years have seen increasing enthusiasm for MPAs as a tool for pelagic conservation. However, numerous criticisms have been levelled against the use of place-based management in such a dynamic environment. Evidence, tools and information to address these criticisms and establish the feasibility and relevance of pelagic MPAs are dispersed across the conservation, oceanography and fisheries management literature. In Chapter 5, I review this information and present a synthetic framework for systematic planning of pelagic MPAs. Although many of the lessons learned so far about MPA design in coastal systems can be transferred to pelagic systems, there are some fundamental differences and new challenges involved in the conservation of patchy and highly dynamic resources. These challenges are very much at the leading edge of new conservation science and are likely to stimulate solutions with impact far beyond the design of pelagic MPAs. 2009-02-11T00:00:00Z Edward Game http://espace.library.uq.edu.au/view/UQ:223892 2010-12-07T00:00:00Z Verity, Christiana Kelsick. http://espace.library.uq.edu.au/view/UQ:158099 Poor reproductive performance of cattle is a problem in many developing countries, the major objectives of this study was to characterise the reproductive performance of Bali cows based upon nutritional management practises where the cattle were (i) grazing (P), (ii) were tethered in paddock during day, tethered at the farmers house at night with grass cut and carried and fed at night (PZ), and (iii) had zero grazing, with all feed supplied to tethered animal via cut and carry (Z). A second objective was to determine the major factors which influence the reproductive performance of these animals. Cattle were identified using ear tags or neck collars (prior to the study most animals had no identification), aged (using their teeth) into groups (1.5 – 3 years of age; 3.5 – 5; 5.5 – 7; > 7 years of age), body condition scored (BCS 1- 5; 1 – emaciated, 2 – lean, 3 – medium, 4 – fat, 5 – very fat), and reproductive status assessed (lactating or not lactating, pregnant or not pregnant). The data were collected three times (March, July and October) over a 9 month period. Data were analysed using SAS. Over the period the mean pregnancy was 57 %. There were no measured seasonal effects on pregnancy rate. Cows that were over 7 years of age (n= 25) had a higher (P< 0.01) pregnancy rate (74%) compared to those aged 1.2 – 3 years of age (37%) (n=25). The majority of cows had BCS of either 2 (n=162) or 3 (n=128). Five cows had a BCS of 5 (very fat) and 10 cows had a BCS of 1 (emaciated). Pregnancy rates increased (P&lt0.05) as BCS increased (37%, 50%, 64%, 73%, 63% respectively for BCS 1 – 5). Over the 9-month, 84% of the P cows, 92% of the PZ cows and 78% of the Z cows were either pregnant and lactating or cycling at one of the three data collections. However, the feeding system had a significant (P< 0.05) effect on pregnancy rate, with the Z cows averaging 30% pregnancy over the 9-month period compared to 58% for h group and 57% for the PZ cows. 2008-11-21T00:00:00Z Faidiban, Oktofianus Rudolf http://espace.library.uq.edu.au/view/UQ:179226 Caulerpa taxifolia is a marine alga notorious for its introduction and subsequent colonization of the Mediterranean Sea. It is recognized as one of the 100 worst invasive species, and it is suggested that much of its expansion may have been at the expense of native seagrass beds. To date, the bulk of research on C. taxifolia has centred on quantifying expansion and methods of eradication. There are few quantitative data on the relationship between C. taxifolia growth and environmental characteristics (e.g. light, temperature, nutrients). Furthermore, once C. taxifolia has been introduced to a system it is exceptionally difficult and expensive to eradicate. Accordingly the implications, both positive and negative, of this new habitat type must be considered in the context of the new habitat mosaic into which it fits. Australia is unique in that it has both native and invasive populations of C. taxifolia. These populations offer not only an opportunity to examine the dynamics of C. taxifolia beds and their associated communities at different latitudes and temperature and light regimes, but especially in the context of a high diversity marine coastal environment. The objectives of this thesis were to use native (Moreton Bay, Queensland) and invasive (Pittwater, New South Wales and Port River, South Australia) populations of C. taxifolia to: 1) quantify the relationship between environmental drivers (light, temperature, nutrients) and C. taxifolia growth, and 2) examine differences in habitat use and function between seagrass, C. taxifolia, unvegetated substrate. Most of the locations in Australia where large C. taxifolia beds occur are adjacent to urban areas that have a degraded water quality. Manipulative experiments in Moreton Bay demonstrated that nutrients stimulate C. taxifolia growth, however, light availability and seasonality appear to influence the response of C. taxifolia growth to nutrients. Short-term manipulative experiments were conducted across a range of seasons and locations, to capture the effects of temperature on growth. Temperature was the dominant factor affecting rate of stolon extension in both native and invasive locations. Colonization potential of C. taxifolia appears to be driven by ambient water quality (light and nutrients) and bed expansion is driven by temperature in systems where nutrients are saturating. Epifaunal communities sampled by beam trawl were dominated by the families Palaeomonidae, Terapontidae, Scorpaenidae, Monacanthidae, Syngnathidae, Gobiidae, and were largely similar between seagrasses and C. taxifolia; however, syngnathids were absent from C. taxifolia beds. I examined habitat use patterns between seagrass (Zostera muelleri), C. taxifolia, and unvegetated substrate. Fish preferred seagrass to C. taxifolia; however, in the absence of a seagrass fish used C. taxifolia. While C. taxifolia may have similar structural benefits to some seagrasses, there are fewer food resources available within C. taxifolia beds. Furthermore, grazing may be limited to a few specialist grazers. Within the habitat mosaic, C. taxifolia will provide some benefit over an unvegetated substrate; however, that benefit might mask losses in system quality or resilience by decreasing the threshold level for change within the community. Therefore, should a perturbation occur (e.g. sudden drop in water temperature, filamentous algal bloom) a system comprised solely of seagrass could withstand such stress; however, a habitat mosaic of seagrass and C. taxifolia could have a rapid and dramatic loss in its ability to sustain a diverse faunal community. Ultimately, it is most important to protect the system from anthropogenic degradation so it is more resilient to environmental changes. 2009-07-13T00:00:00Z Dana Burfeind http://espace.library.uq.edu.au/view/UQ:163266 The thesis considers two pertinent questions about poverty in Fiji. One is about the accuracy of the poverty measures calculated by the concerned organisations and this relates to the use of equivalence scales and the general style of analysis. The other more intricate question is the disregard for poverty due to intra-family distribution asymmetries. Such miscalculations of poverty arise due use of average household per capita expenditure to represent consumption. This research attempts to answer the question of whether the tendency to underestimate the incidence of poverty by disregarding intra-family inequality is significant. Furthermore, it attempts to determine the causes of these inequalities. The issue is whether the classical method of data analysis (using the family as a unit) is the ideal way of analysing poverty and distribution in societies where large family structures exist and government relief remains minimal. To determine the household inequalities, household expenditures have been disaggregated into individualised expenditures. The individualised consumption expenditure is analysed and compared with the outcomes of aggregate household expenditure data. The analysis provides overwhelming evidence for underestimation of poverty when household consumption expenditures are used. 2009-02-06T00:00:00Z Sunil Kumar http://espace.library.uq.edu.au/view/UQ:206479 Immune responses to antigens presented at skin, or other epithelial surfaces such as the cervix, are important for the clearance of viral infections, such as human papillomavirus (HPV) that infect epithelial cells [13]. Elucidation of the components of an effective immune response to antigens presented in this manner will potentially aid in design of immune modulatory techniques or therapeutic vaccine strategies to treat conditions such as cervical cancer. This thesis addresses the role of CD4+ T lymphocytes in immune responses to antigens presented in skin. CD4+ T cells have a well established role in the priming of CD8+ T cells, such that priming without help results in defective CD8+ T cell memory response [15]. The role of CD4+ T cells in the immune response subsequent to priming is less well delineated [15, 16]. Murine skin grafting is a model of antigen presented at an epithelial surface. The model used in this thesis utilises grafts transgenically expressing neo-antigens (human growth hormone=hGH, ovalbumin=OVA) under the control of a keratin promoter (K14 or K5) in the graft. The corresponding mice are termed K14hGH and K5mOVA. With hGH as the antigen, rejection of such skin grafts were shown to require CD4+ T cells [1]. The most surprising finding was that this requirement for CD4+ T cells was maintained even in an antigen-experienced host (in the recall immune response to hGH). CD4+ T cells are required by graft-primed recipients to reject hGH-expressing grafts, but are not required to reject grafts expressing alternative antigens such as OVA. In an adoptive transfer model into lymphopaenic hosts, when high numbers of CD8+ T cells were transferred, any addition of CD4+ T cells was superfluous. However, with low numbers of OVA-specific CD8+ T cells, the addition of CD4+ T cells resulted in a significantly faster rate of K5mOVA skin graft rejection. This helper enhancement of K5mOVA skin graft rejection is maintained, even 7 when CD8+ T cells were previously activated to a memory phenotype prior to transfer, indicating that CD4+ T cells do have effects after CTL priming in vivo. The requirement for CD4+ T cells in the rejection of C57.K14hGH grafts is abrogated by the addition of a local inflammatory stimulus (TLR7 agonist, imiquimod). This is a local rather than systemic effect, suggesting an influence on trafficking or local effector function. Administration of agonist anti-CD40 antibody also partially abrogates the need for CD4+ T cells in rejection of C57.K14hGH grafts by primed hosts. Although CD40 has a well established role in priming of naïve CTL responses, our findings indicate that CD40 can alter events after priming, and suggests a possible mechanism for the role of CD4+ T cells in this system. With these data, we speculate that CD4+ T cells may provide help by altering the state of APC cross-presenting antigen to experienced CD8+ T cells, and that this can be substituted by TLR or CD40 mediated activation of APC. The result may be an increased number of effector CD8+ T cells, as we demonstrate that high numbers of antigen-specific CD8+ T cells can abrogate this effect. 2010-06-28T00:00:00Z Jennifer Broom http://espace.library.uq.edu.au/view/UQ:217386 Members of phylum Planctomycetes of the domain Bacteria are distinctive budding peptidoglycan-less and compartmentalized bacteria from aquatic and soil habitats. It has been previously established that all planctomycetes share a cell plan in which the nucleoid DNA is enclosed by at least one membrane, the intracytoplasmic membrane (ICM), forming a major cell organelle, the pirellulosome. The shared cell structure of planctomycetes also involves a ribosome-free region of the cytoplasm between cytoplasmic membrane and ICM termed the ‘paryphoplasm’. The genomic DNA of Gemmata obscuriglobus within the pirellulosome is further enclosed by two membranes forming an envelope surrounding a nuclear body containing the nucleoid and its DNA. From phase contrast microscopy and TEM of thin-section of cells of G. obscuriglobus prepared by high-pressure freezing techniques, a model for the cell cycle of G. obscuriglobus has been derived in which a mother cell forms a small bud with a narrow neck relative to the mother cell diameter, and this bud gradually enlarges until it is similar in size to the mother cell, a stage which then lasts for a time considerably longer than other stages of cell division. Both the mother cell and the finally released bud are capable of further cell division. During cell division, the earliest visible bud stage does not possess DNA and a naked nucleoid is transferred into the bud when the bud is more matured. This stage is followed by the formation of a double-membrane nucleoid envelope surrounding the nucleoid. The new nucleoid envelope of the bud is derived from existing intracellular membranes of both mother and daughter cells where the inner-membrane of the nucleoid envelope originates from the mother cell ICM and the outer-membrane of the same envelope is derived from the bud ICM. We have extended knowledge of the occurrence of the shared planctomycete cell plan to newly described planctomycetes including Zavarzinella formosa and Ellin6207. These two strains share the major features of the common planctomycete cell plan, but also display unique characteristics. So in Ellin6207 there are unique nucleoid-associated bodies and condensed bodies within the nucleoid, while in Zavarzinella formosa, membrane-bounded vesicle-like entities are situated in the paryphoplasm region, a structural characteristic we have not observed in Gemmata strains fixed by the same methods. The phylum Verrucomicrobia forms a distinct phylogenetically divergent phylum within the domain Bacteria, characterized by members widely distributed in soil and aquatic habitats. A superphylum called the PVC superphylum has been proposed by Wagner and Horn (2006) which comprises mainly the phyla Planctomycetes, Verrucomicrobia and Chlamydiae. Based on the proposed relationships between the three lineages, we hypothesized that members of Planctomycetes and Verrucomicrobia might share a similar ultrastructural plan. Four members of the phylum Verrucomicrobia were examined including Verrucomicrobium spinosum, Prosthecobacter dejongeii, Chthoniobacter flavus and Ellin514. TEM results show that these strains share a basic cell plan analogous to that found in members of the phylum Planctomycetes. This cell plan is in known planctomycetes characterized by compartmentalization of the cell cytoplasm by a major cell organelle bounded by a single membrane containing all the cell DNA in a fibrillar condensed nucleoid, as well as ribosome-like particles. This major membrane-bounded organelle is equivalent to the pirellulosome of planctomycetes, and its bounding membrane is equivalent to the ICM defined in planctomycetes as surrounding the pirellulosome. Consistent with the structural analogies between verrucomicrobia and planctomycetes, the ribosome-free region between the intracytoplasmic membrane of the pirellulosome and the cytoplasmic membrane in verrucomicrobia can be considered equivalent to the paryphoplasm of planctomycetes. We have found that this planctomycete cell plan is present in at least 3 of the 6 subdivisions of the Verrucomicrobia, suggesting that the common ancestor of the verrucomicrobial phylum was also compartmentalized and possessed such a plan. The presence of this compartmentalized cell plan in both phylum Planctomycetes and phylum Verrucomicrobia suggests that the last common ancestor of these phyla was also compartmentalized. Cell compartmentalization of this type may thus have significant meaning phylogenetically, and can act as a clue to the meaning of deeper evolutionary relationships between bacterial phyla. Its occurrence in a second phylum of domain Bacteria extends and reinforces the challenge to the concept of prokaryotic organization already posed by planctomycete cell organization. Members of the phylum Planctomycetes have been shown to lack FtsZ, a bacterial tubulin homologue cell division protein that is conserved virtually in all bacteria, which raises the question of which proteins are responsible for cell division in the members of this group. FtsK is a multifunctional protein that couples cell division and chromosome segregation in Escherichia coli. Nearly all FtsK proteins contain an N-terminal transmembrane domain essential for septum formation, a C-terminal P-loop ATPase and FtsK gamma DNA-binding domains responsible for chromosome segregation and DNA translocation and a central FtsKL domain that is highly divergent between bacterial species and differ in size with functions which have yet to be defined. G. obscuriglobus ftsK gene sequence (2433 bases) was successfully retrieved from the draft genome at TIGR database and the open reading frame of the protein was detected using the NCBI ORF finder program. G. obscuriglobus FtsK has been predicted from our analysis to possess 4 possible transmembrane helices at the N-terminus region and a large hydrophilic C-terminal domain. G. obscuriglobus FtsK possesses two conserved domains at the C-terminal region including a P-loop NTPase superfamily domain and an FtsK gamma DNA-binding domain. These two domains are also conserved in all other bacterial FtsKs. Immunogold labelling showed that FtsK within the pirellulosome is associated mainly with the DNA of the condensed nucleoid but sometimes appears associated with DNA in the process of transfer during cell division, which suggests a role in DNA transfer consistent with that of SpoIIIE protein found in B. subtilis. FtsK of G. obscuriglobus is localized in a specific major membrane-bounded compartment, the pirellulosome, suggesting a functional role in compartmentalization that is unique from FtsK in other organisms. This is consistent with a functional role for the pirellulosome, as indicated by the membrane-delimited localisation within the pirellulosome of a protein of significance for cell division or chromosome segregation. 2010-09-28T00:00:00Z Kuo-chang Lee http://espace.library.uq.edu.au/view/UQ:158115 The aetiology of two groups of psychiatric disorders, schizophrenia and the major depressive disorders, are poorly understood. Unlike neurodegenerative conditions, these two disorders have no obvious neuropathology and clues to their aetiology must be gleaned from other fields of research. The dominant models to date have been neurochemical in nature – based on known actions of drugs that improve or mimic these conditions. However, the resulting monoaminergic hypotheses have been found to be over-simplistic and unable to comprehensively account for these complex psychiatric disorders. Based on epidemiological findings concerning perinatal factors and the typical adolescent age-of-onset, as well as the results of neuroimaging and neuropathological studies, research interest is now shifting to the processes involved in neurodevelopment, brain maturation and homeostasis. This thesis explores two such processes – apoptosis in relation to schizophrenia, and neurogenesis in relation to depressive disorders. The negative associations between cancer, rheumatoid arthritis, and schizophrenia have led to the hypothesis that patients with schizophrenia have an increased susceptibility to programmed cell death (apoptosis). A study was carried out assessing several apoptotic markers in dermal fibroblast cell lines from groups of patients with schizophrenia, patients with non-schizophrenic psychotic disorder, and healthy comparison subjects. Apoptotic nuclei, caspase-3 activity, and protein levels of Bcl-2, Bax and P53P392Ser were quantified. Apoptosis was studied under basal cell culture conditions and after induction using the protein synthesis inhibitor, cycloheximide. The results suggested significant abnormalities in the regulation of apoptosis in schizophrenia that do not occur in non-schizophrenic psychotic disorder. It has been proposed that the therapeutic action of antidepressants is related to their effect on hippocampal neurogenesis mediated by brain-derived neurotrophic factor (BDNF). This hypothesis arose from the finding that blocking the action of BDNF in rodents leads to decreased neurogenesis and increased depressive behaviour. It has also been demonstrated that the neurotrophin receptor, p75NTR, is required for BDNF-induced differentiation of neural precursor cells in vitro, although no in vivo data have been published confirming this. A study was conducted to investigate the effect of running and treatment with the selective serotonin reuptake inhibitor fluoxetine (both positive modulators of neurogenesis) on the pool of hippocampal progenitor cells from which new neurons are derived. The pool of hippocampal progenitor cells was found to be a dynamic population, which varies in proliferative potential with the duration of antidepressant treatment. This variation may be attributable to changes in the number of progenitor cells occurring with prolonged induction of neurogenesis. Whether p75NTR plays a role in the regulation of neurogenesis was then determined. Neurogenesis was found to be reduced in p75NTR knock-out mice, providing us with a mouse model for the study of the role of neurogenesis in depression. Future work will depend on the identification of an appropriate behavioural model of depression that responds to chronic, and not acute, administration of antidepressant medication. A third stream of work involved application of high-throughput technology to investigate gene expression in psychiatric disorders. Clues to the aetiology of psychiatric disorders have been sought from microarray analysis of post-mortem brain tissue. In preparation for a microarray study of post-mortem tissue from a large sample of patients with schizophrenia and depressive disorder, post-mortem mRNA degradation was investigated in mouse brain tissue. A subgroup of mammalian mRNA transcripts was found to be particularly susceptible to post-mortem-related degradation, and to be more likely to carry the AUUUA motif in the 3’ untranslated region. As transcription factors are more likely to carry this motif, this finding brings into question the suitability of post-mortem tissue for the study of apoptosis and cell proliferation. In conclusion, there is epidemiological, neuroimaging and neuropathological evidence that neurodevelopmental and brain maturational processes are involved in schizophrenia and depressive disorders. Supporting this view, the literature review identified a substantial number of laboratory studies implicating apoptosis in schizophrenia, and neurogenesis in depressive disorder. The series of studies conducted for this thesis added to this body of evidence. However, specific pathway abnormalities are yet to be determined. The complex multi-factorial nature of psychiatric disorder suggests that multiple molecular pathways will be implicated, and that future research needs to be conducted on much larger samples using multi-level assays (genotype - gene expression - protein levels - cellular function). Neurobiological studies of schizophrenia and major depression using large sample sizes, convergent experimental approaches, and employing high-throughput technologies will be required to achieve this aim. 2008-11-21T00:00:00Z Catts, Vibeke Sorensen http://espace.library.uq.edu.au/view/UQ:253018 2011-09-23T00:00:00Z Smillie, Anne Ellizabeth. http://espace.library.uq.edu.au/view/UQ:105491 2007-08-24T00:00:00Z Worapamorn, Wilairat. http://espace.library.uq.edu.au/view/UQ:185659 Cytosolic double stranded DNA (dsDNA) is sensed as a “danger signal” by host cells. Detection of viral and bacterial nucleic acid is emerging as a major route for cells to identify an infection by a pathogen. Recognition of cytoplasmic DNA causes death of some cells and interferon (IFN) and cytokine induction, which are appropriate anti-viral responses. Responses to cytoplasmic DNA may not only be relevant to certain retrovirus, DNA virus and bacterial infections, but could also be generated by reverse transcription of endogenous retro-elements. Introduction of DNA into the cytoplasm of bone marrow derived macrophages (BMM) causes upregulation of MHC Class I, induction of IFNβ and other cytokines and cell death. Both cytokine induction and cell death were independent of recognition of “CpG motifs” through TLR9. In order to determine whether a single receptor was likely to mediate these responses, the types of DNA eliciting these responses was compared. Both cellular activation to produce cytokines and IFNβ, as well as cell death were seen only with dsDNA but not single stranded DNA (ssDNA). Both responses increased with increasing DNA length, with little detectable effect of a double stranded 22bp oligonucleotide (ODN). The sequences of DNA leading to optimal induction of IFNβ and death were different. Although all dsDNA induced death of primary macrophages, poly(dA):(dT) was a particularly potent and rapid pro-death stimulus. In contrast, poly(dA):(dT) was a relatively poor stimulus for IFNβ, even at doses which were minimally toxic, or in cells which are resistant to DNA induced cell death. The alternating co-polymer poly(dA-dT) was the most potent inducer of IFNβ. This data suggests that separate DNA receptors mediate cell death and IFNβ induction in response to dsDNA Transfected dsDNA also rapidly activated caspase 3, a classical pro-apoptotic caspase, in BMM as early as 2½ minutes post-transfection with DNA. Caspase 3 is an effector caspase which is activated by an upstream initiator caspase. Although the apical caspase in the DNA detection system has not been defined, use of Bcl2 overexpressing BMM and caspase 2-/- BMM showed that DNA-dependent caspase 3 activation did not occur via the mitochondrial damage or the caspase 2 activation pathways. The inflammatory caspase, caspase 1 was also activated in response to DNA transfection, although whether caspase 1 is responsible for cleavage of caspase 3 has not been established. Caspase 1 activation suggests the involvement of the inflammasome, which is important for processing pro-inflammatory cytokines such as IL-1β into their biologically active forms. Furthermore, there is recent evidence suggesting that DNA-transfected cells die by a caspase 1-dependent cell death called pyroptosis. Other work in our lab identified the HIN-200 family member and candidate lupus susceptibility factor p202 as a candidate receptor for cytoplasmic dsDNA; p202 bound stably and rapidly to transfected DNA. Here, knockdown studies revealed p202 to be a regulatory protein limiting DNA-induced caspase 1 and 3 activation. Conversely, the related pyrin domain-containing HIN-200 factor AIM2 (p210), a candidate tumour suppressor, was required for caspase 1 and 3 activation by cytoplasmic dsDNA. Recently published work suggests that AIM2 multimerises along the length of the DNA leading to the formation of an inflammasome complex. The pyrin domain of AIM2 recruits the adaptor protein ASC through homotypic pyrin domain interactions. ASC subsequently recruits caspase 1, which results in its auto-activation. The inhibitory effect of p202 on caspase activation is likely to be due to its lack of a pyrin signalling domain. p202 rapidly binds to cytoplasmic DNA, and may reduce the clustering of AIM2 pyrin domains which results in caspase activation. Consistent with this proposal, DNA-dependent caspase activation correlated inversely with p202 expresssion in 3 mouse strains. This work defines HIN-200 proteins as a new class of pattern recognition receptors mediating responses to dsDNA. Work in this thesis aimed to understand the biological role and mechanism of responses to cytoplasmic DNA. Responses to cytoplasmic DNA are likely to be relevant not only to infectious disease but also to autoimmune diseases such as systemic lupus erythmatosus (SLE), where DNA appears to act as an adjuvant, and even tumour progression where there is evidence for a role for active endogenous retro-elements. In addition, responses to DNA may limit transfection efficiency and the efficacy of non-viral gene therapy. 2009-11-11T00:00:00Z Adi Haji Idris http://espace.library.uq.edu.au/view/UQ:158548 Treatment of cancer remains largely ineffective despite ongoing efforts to improve therapy modalities. Conventional treatments such as chemotherapy and radiation have proven to be effective in some cases, however the unstable genome of transformed cells leads to mutations and generation of new sub-clones that are able to escape therapeutic control. Overcoming tumour resistance requires the development of alternative or additional modalities of treatment that optimally would possess greater selectivity for tumour targets, provide alternative cytotoxic mechanisms and have non-cross reactive toxicities with current treatments. Cellular immunotherapy is an attractive alternative to conventional treatments. Harnessing the patients’ own immune cell defence system to recognize and kill tumour cells reduces the risk of toxicity associated with administering chemotherapy or radiation and has the potential to be highly specific towards malignant tissue. In many clinical situations there is evidence that combination therapy, utilising two or more modalities of treatment simultaneously, is superior to single agent therapy. Combining drugs or agents on the basis of differing mechanisms of action has the theoretical capacity to increase anti-tumour cytotoxicity with minimal increases in systemic or tissue toxicity. Also, there are reduced chances of resistance emerging when a number of modalities are used. The research undertaken for this dissertation aimed to determine the potential therapeutic benefits of combining cell based immune therapy with chemotherapy agents and the bisphosphonate, zoledronate, for improvements in therapy of solid malignancies. Human immune effector cells, VH24/VO11 NKT cells and VB9VD2 T cells, possess potent cytotoxic anti-tumour activities against a range of tumour cell types without the requirement for MHC-restriction. These effector cell populations were assessed for their direct cytotoxic capacity against solid tumour-derived targets in combination with anti-tumour agents. Mechanistic interactions between effector cells, chemotherapy and zoledronate were investigated and a human in vivo trafficking study of adoptively transferred VB9VD2 T cells was performed to predict the clinical feasibility of this multi-modality approach. Results demonstrate high levels of VB9VD2 T cell and NKT cell cytotoxicity against tumour cell lines in combination treatment with chemotherapeutic agents. Pretreatment with low concentrations of chemotherapy sensitized tumour cells to rapid killing by these effector cells and levels of cytotoxicity approached 90%. Zoledronate pre-treatment of tumour cells induced potent lytic responses by VB9VD2 T cells and also enhanced chemotherapy-induced sensitization resulting in almost 100% cell death of tumour targets in some cases. Mechanisms of cytotoxicity involved a range of pathways, including perforin, TRAIL and FasL, some of which were instigated by the effects of chemotherapy or zoledronate exposure. In vivo migration studies of intravenously administered VB9VD2 T cells show for the first time preferential movement of these cells to large organs and small tumour deposits, but the inability to infiltrate large tumour masses. In conclusion, the administration of NKT cells or VB9VD2 T cells at suitable intervals after chemotherapy and/or zoledronate in a cell based multi-modality therapy approach, may substantially increase anti-tumour activities in a range of solid tumour malignancies and improve patient outcomes. The anticipated benefits of this research are combinations of cancer therapies that are not only more effective than those currently available, but also reduce toxicity associated with conventional treatments. 2008-11-21T00:00:00Z Mattarollo, Stephen Robert http://espace.library.uq.edu.au/view/UQ:188330 Olfactory sensenory neurons (OSNs) of the olfactory epithelium are located in the nasal cavity and project axons that synapse onto dendrites of second-order neurons within the olfactory bulb in neuropil structures termed glomeruli. Each OSN expresses one of the over 1000 odorant receptors (ORs) and are randomly dispersed across one of the four partially overlapping regions of the olfactory epithelium. OSNs expressing a single OR project their axons to typically two symmetrically bilateral glomeruli, one each on the medial and lateral surfaces of the olfactory bulb. The target choice of the OSN axons appears to depend on a combination of molecular determinants that first promote segregation of axons into broad regions of the olfactory bulb and then favor sorting and convergence into specific glomeruli. The role of ORs has clearly been demonstrated to play a significant role in axon sorting and targeting to the glomeruli, however other guidance molecules have clearly been shown to be required in the precise targeting of the OSN axons. During development of the mouse olfactory system, olfactory sensory axons first contact their terminal zone in the glomerular layer of the olfactory bulb during late embryonic period and target to their appropriate glomeruli over the next few days. During this period, many axons can branch inappropriately into several glomeruli and overshoot the target layer and enter deeper layers of the olfactory bulb. The aberrant axonal projections are normally detected within the deeper layers of the bulb up to postnatal day 12. By the end of the second postnatal week, axon trajectories are refined and axons over-projections are seldom observed in adult animals. A detailed understanding of the process of axon over-projections enabled the identification of directional cues that navigate the outgrowing axons to their defined destination. There are two aims of the present thesis, first, to investigate the role of cell surface carbohydrates in the molecular and cellular mechanisms underlying axon navigation in the developing olfactory system. To achieve this aim, transgenic mice expressing two glycosyltransferases (Mgat3 and 5) under the control of OMP promoter to drive expression in all mature OSNs have been generated. The results obtained from these transgenic mice showed that the transgene is expressed based on the ability to detect GFP reporter expression, however no apparent targeting defect in the olfactory pathway was observed from these transgenic mice. The purpose of the second study was twofold: 1) To examine the trajectory of olfactory sensory axons that penetrate past the glomerular layer in OMP-Zsgreen transgenic mice and 2) using in vitro cultures of the olfactory epithelium from OMP-Zsgreen mice which allowed visualization of mature OSN and their axons, together with extract prepared from inner layers of olfactory bulb to elucidate the impact of distinct molecular and cellular cues on defined OSN populations. Our results revealed that targeting of OSN axons was initially imprecise where extensive axons over-projection was observed in early postnatal animals. This targeting error was then refined later in development after the first two postnatal weeks and rarely observed in adult animals. The in vitro study using cultured OE explants to examine the effect of the extract prepared from the inner layers of the olfactory bulb on the axon outgrowth suggests the presence of a repellent activity in the inner layers of the olfactory bulb and that this inibition is stronger in P17.5 animals than P8.5 and P2.5 animals. 2009-11-30T00:00:00Z Man-yee Chan http://espace.library.uq.edu.au/view/UQ:158333 Mammalian olfactory neurons reside with the olfactory neuroepithelium lining the nasal cavity and target specific regions of neuropil within the olfactory bulb in the brain referred to as glomeruli. Primary olfactory neurons in the mouse express one of ~1000 odorant receptors. The neurons expressing the same odorant receptor gene are typically restricted in their distribution to one of four broad zones in the olfactory neuroepithelium, and project to at least two topographically-fixed glomeruli, one each on the medial and lateral surfaces of the olfactory bulb. Throughout life, primary olfactory neurons undergo continuous cell turnover. Mature primary olfactory neurons have a limited lifespan and are replaced by proliferating progenitor cells within basal layers of the neuroepithelium. Unlike in other regions of the nervous system this means that new axons are continually growing along the olfactory and navigating to their target sites. A number of candidate guidance molecules have been identified within the olfactory system that contributes in guiding of olfactory axons within olfactory pathway; however the molecular interactions responsible for growth and guidance remain unknown. Furthermore the role of the target tissue, the olfactory bulb, in providing guidance cues to the olfactory axons is unclear. There were three principal aims of the present thesis. First, to investigate the sorting behavior of olfactory and vomeronasal organ axons during regeneration. Second, to understand the underlying role of the olfactory bulb in formation of the outer layers of the olfactory bulb. Third, to assess the role of the olfactory bulb in guiding axons to their glomerular targets during development. The first aim of this thesis was to understand how primary olfactory and vomeronasal organ axons target specific regions of the olfactory bulb. The sorting behaviour of these axons was examined following neonatal unilateral olfactory bulbectomy. Bulbectomy induced widespread ipsilateral death of the primary olfactory and vomeronasal organ neurons within the nasal cavity and vomeronasal organ, respectively. After four weeks, many new sensory axons had re-grown into the cranial cavity and established a prominent plexus with evidence of dense tufts that were similar in gross appearance to glomeruli. Axons expressing the cell adhesion molecule OCAM, which normally innervate the ventrolateral and rostral halves of the main and accessory olfactory bulbs respectively, were found to sort out and segregate from those axons not expressing this molecule within the plexus. Sorting was also observed for axon subpopulations which were expressing specific cell surface glycoconjugates. In addition, vomeronasal organ axons formed large discrete bundles that segregated from main olfactory axons within the plexus. The second aim of the thesis was to understand the underlying role of the olfactory bulb in development of the outer layers of the olfactory bulb. The olfactory bulbs in OMP-IRES-LacZ and P2-IRES-tau-LacZ neonatal mice were unilaterally removed and replaced with artificial biological scaffolds molded into the shape of an olfactory bulb. Regenerating axons projected around the edge of the cranial cavity at the periphery of the artificial scaffold and were able to form an olfactory nerve fibre layer and, to some extent, a glomerular layer. Our results reveal that olfactory axons are able to form rudimentary cytoarchitectonic layers if they are provided with an appropriately shaped biological scaffold. The third aim of this thesis was to understand the role of the olfactory bulb in the formation of the olfactory nerve pathway. A model was developed whereby the gross shape of the olfactory bulb in P2-IRES-tau-LacZ neonatal mice was disrupted without perturbing olfactory nerve connections. It was demonstrated that the topography of axons expressing the P2 odorant receptor was perturbed when the normal shape of the olfactory bulb was altered. P2 axons instead projected to multiple inappropriate glomeruli surrounding their normal target glomerulus. Our results support the hypothesis that local guidance cues in the bulb direct the final targeting of olfactory axons. In conclusion, the results of this thesis revealed that the sorting and convergence of axons occur independently of the olfactory bulb and are probably attributable either to inherent properties of the axons themselves or to interactions between the axons and accompanying glial ensheathing cells. The bulbectomy studies clearly revealed that the olfactory bulb does not provide any tropic substance that either attracts regenerating olfactory axons into the cranial cavity or induces these axons to form a plexus around its outer surface. However, to the shape of the olfactory bulb is important for directing olfactory axons to their appropriate topographic glomerulus. It is postulated that the surface of the olfactory bulb contains topographic guidance cues that direct the final targeting of olfactory axons. The nature of these cues remains to be determined. 2008-11-21T00:00:00Z Chehrehasa, Fatemeh http://espace.library.uq.edu.au/view/UQ:279283 2012-08-23T00:00:00Z Roberts, Tara Laurine http://espace.library.uq.edu.au/view/UQ:164999 Developmentally regulated G-proteins (DRGs) are a highly conserved family of GTP binding proteins found in archaea, plants, fungi and animals. Their function is poorly understood but they are implicated in cell division, proliferation, and growth, as well as several human medical conditions. The research reported here has utilised a variety of approaches including structural biology, biochemistry, expression profiling, and mutant analysis in order to investigate the cellular function of DRG proteins in plants. Recombinant, biologically active atDRG1 and atDRG2 protein from Arabidopsis thaliana was purified using in vitro refolding and was used in both structural studies and biochemical analysis. Crystallographic studies were carried out for both atDRG1 and atDRG2 across 3840 unique, independent crystallisation conditions for each protein. Heterogeneous nucleation was also used in a separate crystallography screen in order to induce nucleation and subsequent crystal growth however no diffraction quality protein crystal were produced in this study. The nucleotide binding and hydrolysis properties of recombinant atDRG1 and atDRG2 were measured in vitro, representing the first biochemical characterisation of DRG proteins. Both atDRG1 and atDRG2 were found to bind GDP and GTP in vitro without the assistance of exogenous exchange or activation factors. The Kcat for GTP hydrolysis by atDRG1 and atDRG2 was found to be 7.44 x 10-4 min-1 and 1.18 x 10-3 min-1 respectively which is consistent with proteins related to the DRG subfamily. An Arabidopsis thaliana atDRG2a knockout mutant was identified and characterised in this study as well representing the first DRG knockout mutant in a multicellular organism. We found that complete knockout of atDRG2a is not lethal in Arabidopsis and that the nearly identical atDRG2b protein is not upregulated in response to an absence of atDRG2a in the cell. The mutant did not display an obvious phenotype compared to wild-type. The expression profiles of the three Arabidopsis thaliana drg genes, drg1, drg2a, and drg2b, were characterised using drg promoter:GUS Arabidopsis transgenics and revealed several interesting features. Under normal conditions, drg1 and drg2a transcripts are present in all cells whilst drg2b transcripts are undetectable. When heat stress is applied, drg2b and drg1 are specifically up regulated and drg2a is not. During seed imbibition, drg2a and drg1 are specifically upregulated whilst drg2b is not. The expression pattern of the drg family closely mirrors that of chaperone/heat shock proteins and this would agree with previous research that suggests that DRG2a may perform a chaperone role. The ability of DRGs to bind nucleotides without assistance, their slow rate of GTP hydrolysis, heat stress activation, abundance in seeds, cytosolic localization, and domain conservation, all agree with the models proposed for spoOB associated G-protein (Obg) function, whereby Obgs stabilise or refold ribosomes or other proteins in response to stress. It is possible that DRGs perform a similar and complementary function to Obgs, specifically during heat stress, despite the low level of sequence conservation between Obgs and DRGs. 2009-02-23T00:00:00Z Anthony O'Connell