Investigating factors affecting restoration of native grassland in ex-cropland
- Authors: Shakir, Shakir Bahaddin
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Native grasslands are one of the most endangered ecosystems in Australia. Approximately 99% of native grasslands have been disturbed for agriculture and pastoralism. Today, however, many agricultural and grazing lands have been abandoned. Restoring abandoned areas to native grassland is a challenge that must be met if these systems are to persist. This thesis sought to gain a better understanding of the biotic and abiotic barriers to restoring native grasslands in ex-cropping land, and to investigate novel techniques to overcome them in degraded native grassland in the Victorian Volcanic Plains. Firstly, I compared ex-cropland to high-quality remnant grassland, and showed that excropland supports a high number of exotic weeds, a lack of native species propagules, high nutrient levels (especially phosphorus and nitrogen), and an absence of organic carbon—all barriers which must be overcome if native grassland restoration is to succeed. I conducted a replicated field experiment in ex-cropland, to investigate four restoration approaches to overcoming barriers to restoration: (i) adding urban green waste to heat and kill the exotic seed bank (ii) adding sugar and/or mulch to promote microorganism and draw down soil nitrogen, (iii) using a modified clay product called Phoslock to reduce soil phosphorus levels, and (iv) scalping of topsoil 10 cm on ex-cropland site to remove the exotic seed bank and high nutrient soil. After each treatment, native grass seed was added, and the vegetation, seed bank, soil nutrients and microbial activity were monitored over 2.5 years. The hot mulch, scalping and sugar treatments all achieved significantly greater cover of native grasses than the control treatments. The hot waste treatment also effectively eliminated the exotic weed seed bank, but the soil N levels increased dramatically, which is counterproductive to the long-term goals of grassland restoration. Scalping out-performed all other treatments with regard to reducing soil N and P. All treatments suffered from reinvasion by exotic species, suggesting that any grassland restoration technique needs to be coupled with ongoing exotic weed management. Abstract ii High soil phosphorus is a difficult barrier to restoration of native grassland. A possible way to address this is to use plants with high P uptake to help draw down soil P. Native grassland taxa from the genus Ptilotus have been shown to have high P-uptake. I conducted two studies of Ptilotus macrocephalus and Ptilotus polystachyus to investigate their potential in this role. The first of these was an examination of techniques to break their seed dormancy, and to find their optimum germination conditions. I tested their response to smoke water, heating shock, cold stratification and gibberellic acid. The highest germination rates (62% and 38% for P. microcephalus and P. polystachyus, respectively) were achieved when the seeds were pre-treated with GA500 and exposed to a temperature range of (20/18OC) and a 12h dark/12h light regime. Smoke water, heat shock and the removal of floral bracts also improved germination rates, but not at the same magnitude as GA. The second study of Ptilotus was a glasshouse trial that examined the effectiveness of the two taxa at reducing available soil phosphorus. This trial included a third high P-uptake species (Lupinus albus) for comparison, and also investigated if the addition of Phoslock® could bind soil P into insoluble forms. P. macrocephalus and P. polystachyus accumulated high amounts of soil P. Thus, several years of seeding and harvesting of these plants is anticipated to provide a useful option for soil P reduction. Phoslock® reduced soil available P, but only at high concentration of Phoslock 1500 g/m2 and at very high soil P concentrations; it was less effective at levels that typically expect in ex-cropping paddocks. The findings of this thesis have advanced our current knowledge of the restoration of excropland. The research has tested methods to overcome biotic and abiotic barriers to restoration of the Victorian Volcanic Plains grasslands, and has demonstrated some practical approaches to begin the treatment. It was suggested that many of the methods and techniques used in this study could be useful technique in broad areas of grassland restoration within Australia as well as in similar situations in temperate climate conditions across the globe.
- Description: Doctor of Philosophy
- Authors: Shakir, Shakir Bahaddin
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Native grasslands are one of the most endangered ecosystems in Australia. Approximately 99% of native grasslands have been disturbed for agriculture and pastoralism. Today, however, many agricultural and grazing lands have been abandoned. Restoring abandoned areas to native grassland is a challenge that must be met if these systems are to persist. This thesis sought to gain a better understanding of the biotic and abiotic barriers to restoring native grasslands in ex-cropping land, and to investigate novel techniques to overcome them in degraded native grassland in the Victorian Volcanic Plains. Firstly, I compared ex-cropland to high-quality remnant grassland, and showed that excropland supports a high number of exotic weeds, a lack of native species propagules, high nutrient levels (especially phosphorus and nitrogen), and an absence of organic carbon—all barriers which must be overcome if native grassland restoration is to succeed. I conducted a replicated field experiment in ex-cropland, to investigate four restoration approaches to overcoming barriers to restoration: (i) adding urban green waste to heat and kill the exotic seed bank (ii) adding sugar and/or mulch to promote microorganism and draw down soil nitrogen, (iii) using a modified clay product called Phoslock to reduce soil phosphorus levels, and (iv) scalping of topsoil 10 cm on ex-cropland site to remove the exotic seed bank and high nutrient soil. After each treatment, native grass seed was added, and the vegetation, seed bank, soil nutrients and microbial activity were monitored over 2.5 years. The hot mulch, scalping and sugar treatments all achieved significantly greater cover of native grasses than the control treatments. The hot waste treatment also effectively eliminated the exotic weed seed bank, but the soil N levels increased dramatically, which is counterproductive to the long-term goals of grassland restoration. Scalping out-performed all other treatments with regard to reducing soil N and P. All treatments suffered from reinvasion by exotic species, suggesting that any grassland restoration technique needs to be coupled with ongoing exotic weed management. Abstract ii High soil phosphorus is a difficult barrier to restoration of native grassland. A possible way to address this is to use plants with high P uptake to help draw down soil P. Native grassland taxa from the genus Ptilotus have been shown to have high P-uptake. I conducted two studies of Ptilotus macrocephalus and Ptilotus polystachyus to investigate their potential in this role. The first of these was an examination of techniques to break their seed dormancy, and to find their optimum germination conditions. I tested their response to smoke water, heating shock, cold stratification and gibberellic acid. The highest germination rates (62% and 38% for P. microcephalus and P. polystachyus, respectively) were achieved when the seeds were pre-treated with GA500 and exposed to a temperature range of (20/18OC) and a 12h dark/12h light regime. Smoke water, heat shock and the removal of floral bracts also improved germination rates, but not at the same magnitude as GA. The second study of Ptilotus was a glasshouse trial that examined the effectiveness of the two taxa at reducing available soil phosphorus. This trial included a third high P-uptake species (Lupinus albus) for comparison, and also investigated if the addition of Phoslock® could bind soil P into insoluble forms. P. macrocephalus and P. polystachyus accumulated high amounts of soil P. Thus, several years of seeding and harvesting of these plants is anticipated to provide a useful option for soil P reduction. Phoslock® reduced soil available P, but only at high concentration of Phoslock 1500 g/m2 and at very high soil P concentrations; it was less effective at levels that typically expect in ex-cropping paddocks. The findings of this thesis have advanced our current knowledge of the restoration of excropland. The research has tested methods to overcome biotic and abiotic barriers to restoration of the Victorian Volcanic Plains grasslands, and has demonstrated some practical approaches to begin the treatment. It was suggested that many of the methods and techniques used in this study could be useful technique in broad areas of grassland restoration within Australia as well as in similar situations in temperate climate conditions across the globe.
- Description: Doctor of Philosophy
Latrobe Valley circular industrial ecosystem
- Authors: Ghayur, Adeel
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Climate change, energy security, pollution and increasing unemployment in the face of automation are four critical challenges facing every region in the twenty-first century, including the Latrobe Valley in Victoria, Australia. The Valley – location of the largest brown coal deposits and forest industry in the southern hemisphere – is undergoing unprecedented and rapid changes. Its ageing brown coal power plants are retiring and replacements are not planned, leading to job insecurity. Solutions are needed that ensure continued economic activity in the region whilst allowing for the Valley to contribute its fair share in the fight against the climate change. The aim of this study is to investigate a possible local solution that could help tackle these issues of the Latrobe Valley in addition to plastic pollution and energy insecurity. Transitioning from linear to circular materials flow is one possible solution that favours sustainability and job security. Consequently, a multiproduct succinic acid biorefinery is modelled, acting as an industrial hub in a potential Latrobe Valley circular economy. This allows for employment creation in the value-addition of its platform chemicals into carbon negative and environment-friendly products. Additionally, such a biorefinery concept has the capacity to tackle Post-combustion CO2 Capture (PCC) industry’s wastes. It is anticipated that any future utilisation of brown coal as an energy vector would entail PCC to ensure carbon neutrality. A PCC industry produces CO2 and amine wastes that require adequate disposal. The modelled biorefinery has the capacity to valorise both. The simulation and the techno-economic analysis show the modelled Carbon Negative Biorefinery consumes 656,000 metric tonnes (t) of pulp logs and 42,000 t of CO2 to produce 220,000 t of succinic acid, 115,000 t of acetic acid and 900 t of dimethyl ether, annually. Biorefinery’s CAPEX and OPEX stand at AU$ 635,000,000 and $ 180,000,000 respectively. The calculated Minimum Selling Price for succinic acid is $ 990/t, only 6.4% higher than a typical biorefinery. Subsequently, biorefinery’s capacity as an anchor tenant is also simulated via technical evaluations of four value-added products: • Poly(butylene succinate) as biodegradable polymer replacing petro-plastics – simulation results show 1 t of succinic acid produces 0.19 t of tetrahydrofuran and 0.44 t of poly(butylene succinate); • Carbon fibre for insulation products, sporting goods and foams – 1 t of lignin and 0.8 t of acetic anhydride produce 0.8 t of carbon fibre; • Succinylated lignin adhesive for replacing urea-formaldehyde in the wood industry – simulation results show the biorefinery concept having the capacity to valorise both waste amine and CO2 from a PCC plant; and • Renewable fuels like hydrogen as energy vectors – a small biorefinery can potentially provide dozens of gigawatt hours of stored power for backup and peak demands, annually. In summary, results of this research are: • A biorefinery can valorise PCC plant wastes; • Multiproduct succinic acid biorefinery is economically viable; • Renewable fuels are ideally suited as energy storage vectors for a renewable energy grid both in developing and developed countries; • Bioproducts can reduce CO2 emissions thereby mitigate climate change; • Bioproducts can replace petro-products and reduce pollution; • Bioproducts can replace construction industry materials associated with CO2 emissions; • Biorefineries can help a region transition from a linear to a circular economy; and • Circular economies have the potential to generate secure jobs. In conclusion, this research identifies platform biochemicals as potential key drivers in a linear economy’s transition to a circular economy.
- Description: Doctor of Philosophy
- Authors: Ghayur, Adeel
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Climate change, energy security, pollution and increasing unemployment in the face of automation are four critical challenges facing every region in the twenty-first century, including the Latrobe Valley in Victoria, Australia. The Valley – location of the largest brown coal deposits and forest industry in the southern hemisphere – is undergoing unprecedented and rapid changes. Its ageing brown coal power plants are retiring and replacements are not planned, leading to job insecurity. Solutions are needed that ensure continued economic activity in the region whilst allowing for the Valley to contribute its fair share in the fight against the climate change. The aim of this study is to investigate a possible local solution that could help tackle these issues of the Latrobe Valley in addition to plastic pollution and energy insecurity. Transitioning from linear to circular materials flow is one possible solution that favours sustainability and job security. Consequently, a multiproduct succinic acid biorefinery is modelled, acting as an industrial hub in a potential Latrobe Valley circular economy. This allows for employment creation in the value-addition of its platform chemicals into carbon negative and environment-friendly products. Additionally, such a biorefinery concept has the capacity to tackle Post-combustion CO2 Capture (PCC) industry’s wastes. It is anticipated that any future utilisation of brown coal as an energy vector would entail PCC to ensure carbon neutrality. A PCC industry produces CO2 and amine wastes that require adequate disposal. The modelled biorefinery has the capacity to valorise both. The simulation and the techno-economic analysis show the modelled Carbon Negative Biorefinery consumes 656,000 metric tonnes (t) of pulp logs and 42,000 t of CO2 to produce 220,000 t of succinic acid, 115,000 t of acetic acid and 900 t of dimethyl ether, annually. Biorefinery’s CAPEX and OPEX stand at AU$ 635,000,000 and $ 180,000,000 respectively. The calculated Minimum Selling Price for succinic acid is $ 990/t, only 6.4% higher than a typical biorefinery. Subsequently, biorefinery’s capacity as an anchor tenant is also simulated via technical evaluations of four value-added products: • Poly(butylene succinate) as biodegradable polymer replacing petro-plastics – simulation results show 1 t of succinic acid produces 0.19 t of tetrahydrofuran and 0.44 t of poly(butylene succinate); • Carbon fibre for insulation products, sporting goods and foams – 1 t of lignin and 0.8 t of acetic anhydride produce 0.8 t of carbon fibre; • Succinylated lignin adhesive for replacing urea-formaldehyde in the wood industry – simulation results show the biorefinery concept having the capacity to valorise both waste amine and CO2 from a PCC plant; and • Renewable fuels like hydrogen as energy vectors – a small biorefinery can potentially provide dozens of gigawatt hours of stored power for backup and peak demands, annually. In summary, results of this research are: • A biorefinery can valorise PCC plant wastes; • Multiproduct succinic acid biorefinery is economically viable; • Renewable fuels are ideally suited as energy storage vectors for a renewable energy grid both in developing and developed countries; • Bioproducts can reduce CO2 emissions thereby mitigate climate change; • Bioproducts can replace petro-products and reduce pollution; • Bioproducts can replace construction industry materials associated with CO2 emissions; • Biorefineries can help a region transition from a linear to a circular economy; and • Circular economies have the potential to generate secure jobs. In conclusion, this research identifies platform biochemicals as potential key drivers in a linear economy’s transition to a circular economy.
- Description: Doctor of Philosophy
Making junior cricket safer for Sri Lanka : Creating opportunities for injury prevention
- Authors: Gamage, Prasanna
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: With the immense popularity of the game of cricket in Sri Lanka, school level cricket is played competitively and socially by a large number of participants. As in many other sports, musculoskeletal injuries are a common occurrence in cricket. Exposure to hot and humid environments in Sri Lankan conditions during outdoor cricket play can also pose a risk for junior cricketers. To date, there has been no attempt to examine injury or illness among Sri Lankan junior cricketers, which hinders opportunities for injury prevention. The first aim of this thesis was to examine musculoskeletal injuries with a view to identifying injury incidence and associated risks during competitions. Specific injuries among different groups of cricketers were identified including 46.0% in fielders, 25.4% in bowlers and 20.3% in batters. Injury risk perceptions of junior cricketers recognised that these injuries were common, and highlighted the role of coaches and school cricket teachers in supporting junior cricketers. The second aim of the thesis was to study the potential impact of exertional heat illnesses (EHI) during cricket play. A considerable variation in heat stress risk parameters (climate, duration, and intensity of play) were observed among cricketers during test-cricket play. Study of risk perceptions related to EHI showed the importance of understanding EHI risks such as humidity and use of helmets. The results of this PhD have been provided to Sri Lankan Cricket and school cricket authorities with recommendation to develop and implement injury preventive measures such as use of helmets during batting to minimise the high number of match-time-loss facial injuries, and educating junior cricketers in modifying their perceived risk attitudes and beliefs related to musculoskeletal and EHI risks. Overall, this PhD has met the aim of completing the first large-scale scientific contribution towards promoting safety and preventing injuries among Sri Lankan junior cricketers.
- Description: Doctor of Philosophy
- Authors: Gamage, Prasanna
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: With the immense popularity of the game of cricket in Sri Lanka, school level cricket is played competitively and socially by a large number of participants. As in many other sports, musculoskeletal injuries are a common occurrence in cricket. Exposure to hot and humid environments in Sri Lankan conditions during outdoor cricket play can also pose a risk for junior cricketers. To date, there has been no attempt to examine injury or illness among Sri Lankan junior cricketers, which hinders opportunities for injury prevention. The first aim of this thesis was to examine musculoskeletal injuries with a view to identifying injury incidence and associated risks during competitions. Specific injuries among different groups of cricketers were identified including 46.0% in fielders, 25.4% in bowlers and 20.3% in batters. Injury risk perceptions of junior cricketers recognised that these injuries were common, and highlighted the role of coaches and school cricket teachers in supporting junior cricketers. The second aim of the thesis was to study the potential impact of exertional heat illnesses (EHI) during cricket play. A considerable variation in heat stress risk parameters (climate, duration, and intensity of play) were observed among cricketers during test-cricket play. Study of risk perceptions related to EHI showed the importance of understanding EHI risks such as humidity and use of helmets. The results of this PhD have been provided to Sri Lankan Cricket and school cricket authorities with recommendation to develop and implement injury preventive measures such as use of helmets during batting to minimise the high number of match-time-loss facial injuries, and educating junior cricketers in modifying their perceived risk attitudes and beliefs related to musculoskeletal and EHI risks. Overall, this PhD has met the aim of completing the first large-scale scientific contribution towards promoting safety and preventing injuries among Sri Lankan junior cricketers.
- Description: Doctor of Philosophy
Malmsbury bluestone and quarries : Finding holes in history and heritage
- Authors: Walter, Susan
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Malmsbury bluestone was used widely from 1856 in buildings in Victoria, throughout Australia, and in New Zealand. It features in many structures listed on heritage registers, yet its presence is barely recognised. This largely results from the stone quarries, buildings and the men who laboured with it being absent from modern Australian historiography. The fame previously associated with the stone was lost when stone use for structural purposes, and the associated stone skills, declined; a situation exacerbated by poor recognition of the stone industry’s role in building our nation through heritage citations of structures. Inspired by E. P. Thompson, this thesis uses Critical Inquiry though microhistory and landscape analysis to regain the stone’s fame and rescue stoneworkers from the condescension of history. A detailed analysis of quarries, structures, the bluestone industry, and a rarely-attempted total reconstitution of the lives of 194 vital stoneworkers, reveals a valuable cultural heritage currently undervalued and at risk. Malmsbury stoneworkers came from diverse backgrounds but worked co-operatively to promote and sustain a local industry which supplied a nationally-vital building material, despite the absence of a regulatory framework to protect their lives and rights. Scientific methods document the geological properties of the stone and demonstrate how, in the absence of science, skilled stoneworkers nevertheless identified and worked a valuable resource. Modern science could however be used to test building stones in a non-destructive manner to determine the sources of currently unidentified building stones. This thesis significantly contributes to the limited discourse on the history and heritage of Australian stone use through the perspectives of cultural landscapes, labour history and built and cultural heritage. Malmsbury bluestone truly was the standard of excellence and, along with stoneworkers, warrants more extensive recognition in Australia’s Heritage registers.
- Description: Doctor of Philosophy
- Authors: Walter, Susan
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Malmsbury bluestone was used widely from 1856 in buildings in Victoria, throughout Australia, and in New Zealand. It features in many structures listed on heritage registers, yet its presence is barely recognised. This largely results from the stone quarries, buildings and the men who laboured with it being absent from modern Australian historiography. The fame previously associated with the stone was lost when stone use for structural purposes, and the associated stone skills, declined; a situation exacerbated by poor recognition of the stone industry’s role in building our nation through heritage citations of structures. Inspired by E. P. Thompson, this thesis uses Critical Inquiry though microhistory and landscape analysis to regain the stone’s fame and rescue stoneworkers from the condescension of history. A detailed analysis of quarries, structures, the bluestone industry, and a rarely-attempted total reconstitution of the lives of 194 vital stoneworkers, reveals a valuable cultural heritage currently undervalued and at risk. Malmsbury stoneworkers came from diverse backgrounds but worked co-operatively to promote and sustain a local industry which supplied a nationally-vital building material, despite the absence of a regulatory framework to protect their lives and rights. Scientific methods document the geological properties of the stone and demonstrate how, in the absence of science, skilled stoneworkers nevertheless identified and worked a valuable resource. Modern science could however be used to test building stones in a non-destructive manner to determine the sources of currently unidentified building stones. This thesis significantly contributes to the limited discourse on the history and heritage of Australian stone use through the perspectives of cultural landscapes, labour history and built and cultural heritage. Malmsbury bluestone truly was the standard of excellence and, along with stoneworkers, warrants more extensive recognition in Australia’s Heritage registers.
- Description: Doctor of Philosophy
Managed identities : How do Australian university students who stutter negotiate their studies?
- Authors: Meredith, Grant
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Previous social research focused on people who stutter has problematised and largely ignored the experiences of university students who stutter, relying heavily upon surveys of teachers and peers while almost ignoring the authentic voices of students who stutter. Using a novel bricolage approach incorporating autoethnography, this project posed the question: “How do students who stutter negotiate their university experiences in Australia?” In 2008, a unique, web-based audit of 39 Australian public universities concluded that little publicly accessible information about stuttering support services was available for prospective university students. In many ways, stuttering is absent from disability classifications and service systems in higher education. An online survey of 102 Australian university students who stutter, and follow-up individual interviews with 15 students, revealed how these students manage their social identities from enrolment through to graduation. Only a minority of students reported ever formally disclosing their functional impairment to university support services or academic staff. This meant they rejected and/or avoided the disability label and associated stigma. The students were found to exercise a high degree of individual agency and creativity throughout their university journey. Many employed ‘concessional bargaining’ techniques to effectively navigate the oral assessment requirements during their degrees. Analysis of the interview and survey data is interspersed with critical self-reflection by the author – as a university lecturer who himself stutters. This thesis makes a significant contribution to shaping our understanding of the social identities and trajectories of university students who stutter. These students have been recast as positive, purposeful, resourceful and creative agents whose actions can be largely understood from a social model of disability. A series of recommendations for supporting and teaching these students are made to key stakeholders in higher education.
- Description: Doctor of Philosophy
- Authors: Meredith, Grant
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Previous social research focused on people who stutter has problematised and largely ignored the experiences of university students who stutter, relying heavily upon surveys of teachers and peers while almost ignoring the authentic voices of students who stutter. Using a novel bricolage approach incorporating autoethnography, this project posed the question: “How do students who stutter negotiate their university experiences in Australia?” In 2008, a unique, web-based audit of 39 Australian public universities concluded that little publicly accessible information about stuttering support services was available for prospective university students. In many ways, stuttering is absent from disability classifications and service systems in higher education. An online survey of 102 Australian university students who stutter, and follow-up individual interviews with 15 students, revealed how these students manage their social identities from enrolment through to graduation. Only a minority of students reported ever formally disclosing their functional impairment to university support services or academic staff. This meant they rejected and/or avoided the disability label and associated stigma. The students were found to exercise a high degree of individual agency and creativity throughout their university journey. Many employed ‘concessional bargaining’ techniques to effectively navigate the oral assessment requirements during their degrees. Analysis of the interview and survey data is interspersed with critical self-reflection by the author – as a university lecturer who himself stutters. This thesis makes a significant contribution to shaping our understanding of the social identities and trajectories of university students who stutter. These students have been recast as positive, purposeful, resourceful and creative agents whose actions can be largely understood from a social model of disability. A series of recommendations for supporting and teaching these students are made to key stakeholders in higher education.
- Description: Doctor of Philosophy
Mine evaluation optimisation
- Authors: Grigoryev, Igor
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: The definition of a mineral resource during exploration is a fundamental part of lease evaluation, which establishes the fair market value of the entire asset being explored in the open market. Since exact prediction of grades between sampled points is not currently possible by conventional methods, an exact agreement between predicted and actual grades will nearly always contain some error. These errors affect the evaluation of resources so impacting on characterisation of risks, financial projections and decisions about whether it is necessary to carry on with the further phases or not. The knowledge about minerals below the surface, even when it is based upon extensive geophysical analysis and drilling, is often too fragmentary to indicate with assurance where to drill, how deep to drill and what can be expected. Thus, the exploration team knows only the density of the rock and the grade along the core. The purpose of this study is to improve the process of resource evaluation in the exploration stage by increasing prediction accuracy and making an alternative assessment about the spatial characteristics of gold mineralisation. There is significant industrial interest in finding alternatives which may speed up the drilling phase, identify anomalies, worthwhile targets and help in establishing fair market value. Recent developments in nonconvex optimisation and high-dimensional statistics have led to the idea that some engineering problems such as predicting gold variability at the exploration stage can be solved with the application of clusterwise linear and penalised maximum likelihood regression techniques. This thesis attempts to solve the distribution of the mineralisation in the underlying geology using clusterwise linear regression and convex Least Absolute Shrinkage and Selection Operator (LASSO) techniques. The two presented optimisation techniques compute predictive solutions within a domain using physical data provided directly from drillholes. The decision-support techniques attempt a useful compromise between the traditional and recently introduced methods in optimisation and regression analysis that are developed to improve exploration targeting and to predict the gold occurrences at previously unsampled locations.
- Description: Doctor of Philosophy
- Authors: Grigoryev, Igor
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: The definition of a mineral resource during exploration is a fundamental part of lease evaluation, which establishes the fair market value of the entire asset being explored in the open market. Since exact prediction of grades between sampled points is not currently possible by conventional methods, an exact agreement between predicted and actual grades will nearly always contain some error. These errors affect the evaluation of resources so impacting on characterisation of risks, financial projections and decisions about whether it is necessary to carry on with the further phases or not. The knowledge about minerals below the surface, even when it is based upon extensive geophysical analysis and drilling, is often too fragmentary to indicate with assurance where to drill, how deep to drill and what can be expected. Thus, the exploration team knows only the density of the rock and the grade along the core. The purpose of this study is to improve the process of resource evaluation in the exploration stage by increasing prediction accuracy and making an alternative assessment about the spatial characteristics of gold mineralisation. There is significant industrial interest in finding alternatives which may speed up the drilling phase, identify anomalies, worthwhile targets and help in establishing fair market value. Recent developments in nonconvex optimisation and high-dimensional statistics have led to the idea that some engineering problems such as predicting gold variability at the exploration stage can be solved with the application of clusterwise linear and penalised maximum likelihood regression techniques. This thesis attempts to solve the distribution of the mineralisation in the underlying geology using clusterwise linear regression and convex Least Absolute Shrinkage and Selection Operator (LASSO) techniques. The two presented optimisation techniques compute predictive solutions within a domain using physical data provided directly from drillholes. The decision-support techniques attempt a useful compromise between the traditional and recently introduced methods in optimisation and regression analysis that are developed to improve exploration targeting and to predict the gold occurrences at previously unsampled locations.
- Description: Doctor of Philosophy
Neural malware detection
- Authors: Park, Sean
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: At the heart of today’s malware problem lies theoretically infinite diversity created by metamorphism. The majority of conventional machine learning techniques tackle the problem with the assumptions that a sufficiently large number of training samples exist and that the training set is independent and identically distributed. However, the lack of semantic features combined with the models under these wrong assumptions result largely in overfitting with many false positives against real world samples, resulting in systems being left vulnerable to various adversarial attacks. A key observation is that modern malware authors write a script that automatically generates an arbitrarily large number of diverse samples that share similar characteristics in program logic, which is a very cost-effective way to evade detection with minimum effort. Given that many malware campaigns follow this paradigm of economic malware manufacturing model, the samples within a campaign are likely to share coherent semantic characteristics. This opens up a possibility of one-to-many detection. Therefore, it is crucial to capture this non-linear metamorphic pattern unique to the campaign in order to detect these seemingly diverse but identically rooted variants. To address these issues, this dissertation proposes novel deep learning models, including generative static malware outbreak detection model, generative dynamic malware detection model using spatio-temporal isomorphic dynamic features, and instruction cognitive malware detection. A comparative study on metamorphic threats is also conducted as part of the thesis. Generative adversarial autoencoder (AAE) over convolutional network with global average pooling is introduced as a fundamental deep learning framework for malware detection, which captures highly complex non-linear metamorphism through translation invariancy and local variation insensitivity. Generative Adversarial Network (GAN) used as a part of the framework enables oneshot training where semantically isomorphic malware campaigns are identified by a single malware instance sampled from the very initial outbreak. This is a major innovation because, to the best of our knowledge, no approach has been found to this challenging training objective against the malware distribution that consists of a large number of very sparse groups artificially driven by arms race between attackers and defenders. In addition, we propose a novel method that extracts instruction cognitive representation from uninterpreted raw binary executables, which can be used for oneto- many malware detection via one-shot training against frequency spectrum of the Transformer’s encoded latent representation. The method works regardless of the presence of diverse malware variations while remaining resilient to adversarial attacks that mostly use random perturbation against raw binaries. Comprehensive performance analyses including mathematical formulations and experimental evaluations are provided, with the proposed deep learning framework for malware detection exhibiting a superior performance over conventional machine learning methods. The methods proposed in this thesis are applicable to a variety of threat environments here artificially formed sparse distributions arise at the cyber battle fronts.
- Description: Doctor of Philosophy
- Authors: Park, Sean
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: At the heart of today’s malware problem lies theoretically infinite diversity created by metamorphism. The majority of conventional machine learning techniques tackle the problem with the assumptions that a sufficiently large number of training samples exist and that the training set is independent and identically distributed. However, the lack of semantic features combined with the models under these wrong assumptions result largely in overfitting with many false positives against real world samples, resulting in systems being left vulnerable to various adversarial attacks. A key observation is that modern malware authors write a script that automatically generates an arbitrarily large number of diverse samples that share similar characteristics in program logic, which is a very cost-effective way to evade detection with minimum effort. Given that many malware campaigns follow this paradigm of economic malware manufacturing model, the samples within a campaign are likely to share coherent semantic characteristics. This opens up a possibility of one-to-many detection. Therefore, it is crucial to capture this non-linear metamorphic pattern unique to the campaign in order to detect these seemingly diverse but identically rooted variants. To address these issues, this dissertation proposes novel deep learning models, including generative static malware outbreak detection model, generative dynamic malware detection model using spatio-temporal isomorphic dynamic features, and instruction cognitive malware detection. A comparative study on metamorphic threats is also conducted as part of the thesis. Generative adversarial autoencoder (AAE) over convolutional network with global average pooling is introduced as a fundamental deep learning framework for malware detection, which captures highly complex non-linear metamorphism through translation invariancy and local variation insensitivity. Generative Adversarial Network (GAN) used as a part of the framework enables oneshot training where semantically isomorphic malware campaigns are identified by a single malware instance sampled from the very initial outbreak. This is a major innovation because, to the best of our knowledge, no approach has been found to this challenging training objective against the malware distribution that consists of a large number of very sparse groups artificially driven by arms race between attackers and defenders. In addition, we propose a novel method that extracts instruction cognitive representation from uninterpreted raw binary executables, which can be used for oneto- many malware detection via one-shot training against frequency spectrum of the Transformer’s encoded latent representation. The method works regardless of the presence of diverse malware variations while remaining resilient to adversarial attacks that mostly use random perturbation against raw binaries. Comprehensive performance analyses including mathematical formulations and experimental evaluations are provided, with the proposed deep learning framework for malware detection exhibiting a superior performance over conventional machine learning methods. The methods proposed in this thesis are applicable to a variety of threat environments here artificially formed sparse distributions arise at the cyber battle fronts.
- Description: Doctor of Philosophy
New insights into wild deer population genetics, ecology and impacts : implications for management in south eastern Australia
- Authors: Davies, Christopher
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis is a compilation of my own work, driven by my interest into the ecology and impacts of introduced deer in Victoria. My interest in deer initially lead me to undertake an honours project, focussed on deer as a vector for parasites that can affect domestic livestock. During my honours year it became apparent that little was known about the ecology of wild deer throughout south east Australia. My PhD study was therefore developed to fill knowledge gaps of deer ecology, with a focus on developing and optimising ecological tools to generate data to improve deer management strategies. There are many methods available which can be used to collect ecological data on invasive species, such as deer. For my study, I chose methods from four quite discrete fields; global positioning systems (GPS) tracking, population genetics, camera trapping and spatial modelling. These methods were chosen as they are commonly used in ecological studies of invasive species. During my candidature significant attempts were made to deploy GPS collars onto sambar deer to investigate their movement patterns. Movement pattern data is extremely useful and can provide insights into habitat preferences, dispersal ability and other information useful for management. Significant time (around 12 months) was spent applying for ethics approval, gaining relevant approvals, permits and licenses to perform this work as well as performing collaring attempts. Unfortunately all attempts were unsuccessful and the investigation of sambar deer movement patterns had to be abandoned. This highlights the difficulties of working with cryptic deer species inhabiting difficult terrain. The other fields of research pursued (population genetics, camera trapping and spatial modelling) were more successful, the results of which are presented and discussed in this thesis. As the three methods employed in this study are taken from very different fields, a number of experts were enlisted to guide the respective data chapters. The population genetic studies (Chapters two and three) were guided by my primary supervisor Dr Fiona Hogan. I conducted all scat collections from across Victoria, including French Island and Mount Cole and performed all DNA isolations (over 300 in total). Population structure analysis for chapter three was undertaken with the assistance of Dr Faye Wedrowicz and Dr Carlo Pacioni. The camera trapping study (Chapter four) involved deploying camera traps in Baw Baw National Park, which I conducted myself. Occupancy and detectability data analysis for chapter four was performed with the assistance of Dr Hugh Davies. Spatial modelling (Chapter five) which focussed on modelling deer-vehicle collision risk across Victoria was directed by Dr Casey Visintin. Chapter’s two to five are written as independent scientific publications, therefore there is some unavoidable repetition within the thesis as a whole. Minor changes have been made to the formatting of the published papers to keep style consistent within the thesis.
- Description: Doctor of Philosophy
- Authors: Davies, Christopher
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis is a compilation of my own work, driven by my interest into the ecology and impacts of introduced deer in Victoria. My interest in deer initially lead me to undertake an honours project, focussed on deer as a vector for parasites that can affect domestic livestock. During my honours year it became apparent that little was known about the ecology of wild deer throughout south east Australia. My PhD study was therefore developed to fill knowledge gaps of deer ecology, with a focus on developing and optimising ecological tools to generate data to improve deer management strategies. There are many methods available which can be used to collect ecological data on invasive species, such as deer. For my study, I chose methods from four quite discrete fields; global positioning systems (GPS) tracking, population genetics, camera trapping and spatial modelling. These methods were chosen as they are commonly used in ecological studies of invasive species. During my candidature significant attempts were made to deploy GPS collars onto sambar deer to investigate their movement patterns. Movement pattern data is extremely useful and can provide insights into habitat preferences, dispersal ability and other information useful for management. Significant time (around 12 months) was spent applying for ethics approval, gaining relevant approvals, permits and licenses to perform this work as well as performing collaring attempts. Unfortunately all attempts were unsuccessful and the investigation of sambar deer movement patterns had to be abandoned. This highlights the difficulties of working with cryptic deer species inhabiting difficult terrain. The other fields of research pursued (population genetics, camera trapping and spatial modelling) were more successful, the results of which are presented and discussed in this thesis. As the three methods employed in this study are taken from very different fields, a number of experts were enlisted to guide the respective data chapters. The population genetic studies (Chapters two and three) were guided by my primary supervisor Dr Fiona Hogan. I conducted all scat collections from across Victoria, including French Island and Mount Cole and performed all DNA isolations (over 300 in total). Population structure analysis for chapter three was undertaken with the assistance of Dr Faye Wedrowicz and Dr Carlo Pacioni. The camera trapping study (Chapter four) involved deploying camera traps in Baw Baw National Park, which I conducted myself. Occupancy and detectability data analysis for chapter four was performed with the assistance of Dr Hugh Davies. Spatial modelling (Chapter five) which focussed on modelling deer-vehicle collision risk across Victoria was directed by Dr Casey Visintin. Chapter’s two to five are written as independent scientific publications, therefore there is some unavoidable repetition within the thesis as a whole. Minor changes have been made to the formatting of the published papers to keep style consistent within the thesis.
- Description: Doctor of Philosophy
Re(dis)covering the creative power of eros : finding liberation from neoliberalism through the feminist awakening of aphrodite-demeter consciousness
- Authors: Clements. Eileen
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: There is a problem with western patriarchal capitalist narratives of love and connected models of subjectivity which some feminisms, in particular, neoliberal (post)feminism, continue rather than criticise. This is a problem, not only because these feminisms uphold existing patriarchal structures and values, but because models of patriarchal subjectivity are founded on a repression and devaluation of love that contributes to what I am naming a ‘crisis of love’ in neoliberal societies. While some solutions to this problem have been offered, including by feminist love studies scholars, none of the solutions address the whole issue – for example, feminisms that ignore issues of spirituality and the female subject’s relationship to the divine, and the impact of myth on the psyche. Until these aspects are included in a rethinking of both female subjectivity and narratives of love, the problem will not be solved. There are many kinds of love but Eros in particular, which is such a charged narrative in western patriarchal capitalist society, is the kind of love that most urgently needs to be rethought and re(dis)covered. Through examination of the major founding myth of female subjectivity for western patriarchy – the Madonna/whore binary – a pathway to addressing this problem of love becomes possible. Rethinking this binary according to reinterpretations of the myths of Aphrodite and Demeter offers a rethinking of Eros as a creative, life-affirming power. This renewed narrative of Eros creates new models of female subjectivity – and the potentiality for new models of ethics – that challenge the contemporary neoliberal paradigm.
- Description: Doctor of Philosophy
- Authors: Clements. Eileen
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: There is a problem with western patriarchal capitalist narratives of love and connected models of subjectivity which some feminisms, in particular, neoliberal (post)feminism, continue rather than criticise. This is a problem, not only because these feminisms uphold existing patriarchal structures and values, but because models of patriarchal subjectivity are founded on a repression and devaluation of love that contributes to what I am naming a ‘crisis of love’ in neoliberal societies. While some solutions to this problem have been offered, including by feminist love studies scholars, none of the solutions address the whole issue – for example, feminisms that ignore issues of spirituality and the female subject’s relationship to the divine, and the impact of myth on the psyche. Until these aspects are included in a rethinking of both female subjectivity and narratives of love, the problem will not be solved. There are many kinds of love but Eros in particular, which is such a charged narrative in western patriarchal capitalist society, is the kind of love that most urgently needs to be rethought and re(dis)covered. Through examination of the major founding myth of female subjectivity for western patriarchy – the Madonna/whore binary – a pathway to addressing this problem of love becomes possible. Rethinking this binary according to reinterpretations of the myths of Aphrodite and Demeter offers a rethinking of Eros as a creative, life-affirming power. This renewed narrative of Eros creates new models of female subjectivity – and the potentiality for new models of ethics – that challenge the contemporary neoliberal paradigm.
- Description: Doctor of Philosophy
Reciprocal peer tutoring in an Australian undergraduate clinical skills setting : A mixed methods study
- Authors: Gazula, Swapnali
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background Incorporation of active learning approaches in the preparation of nursing students for future educational roles is an imperative. Reciprocal peer tutoring (RPT) is an active teaching/learning approach, in which individuals from similar academic levels rotate teaching/learning roles. This study aimed to explore the outcomes of RPT on undergraduate nursing students learning. Design/Methods A sequential explanatory mixed methods design, incorporating pre-post intervention surveys and focus groups with a convenience sample of 102 final-year students, from a cohort of 132 (RR = 77.3%), from a regional Australian university campus. Prior to attendance, online resources were provided on teaching fundamentals and two selected clinical skills, namely tracheostomy suctioning and intravenous cannulation. Attending participants were randomly allocated into pairs, rotating teaching and learning roles within clinical skills laboratories. Pre-post intervention survey tools examined knowledge and self-reported attitudes to a peer teaching and clinical teaching preferences (Clinical Teaching Preference Questionnaire). Post-intervention measures included a peer teaching experience (Peer Teaching Experience Questionnaire). Focus group interviews (n = 4) were conducted with 22 participants, to further understand students’ RPT experiences. Results There was positive improvement in attitudes to peer teaching (M = 49.2, SD = 10.0 to M = 52.3, SD = 8.2, p < 0.05, [95% CI = 0.7 to 5.4]). Knowledge scores also increased significantly (M = 6.9, SD = 2.0 to M = 9.7, SD = 1.9), p < 0.05 [95% CI = 2.3 to 3.2]. Aggregate mean knowledge scores increased more for peer teachers (M = 3.3) than they did for peer learners (M = 2.2). Thematic outcomes from focus groups indicated challenging yet beneficial journeys, collective learning outcomes, along with benefits of RPT including enhanced teaching, self-confidence, communication, and independent and collaborative learning. Conclusion This study concludes that RPT is effective in clinical skills teaching and sets a foundation for further research.
- Description: Doctor of Philosophy
- Authors: Gazula, Swapnali
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Background Incorporation of active learning approaches in the preparation of nursing students for future educational roles is an imperative. Reciprocal peer tutoring (RPT) is an active teaching/learning approach, in which individuals from similar academic levels rotate teaching/learning roles. This study aimed to explore the outcomes of RPT on undergraduate nursing students learning. Design/Methods A sequential explanatory mixed methods design, incorporating pre-post intervention surveys and focus groups with a convenience sample of 102 final-year students, from a cohort of 132 (RR = 77.3%), from a regional Australian university campus. Prior to attendance, online resources were provided on teaching fundamentals and two selected clinical skills, namely tracheostomy suctioning and intravenous cannulation. Attending participants were randomly allocated into pairs, rotating teaching and learning roles within clinical skills laboratories. Pre-post intervention survey tools examined knowledge and self-reported attitudes to a peer teaching and clinical teaching preferences (Clinical Teaching Preference Questionnaire). Post-intervention measures included a peer teaching experience (Peer Teaching Experience Questionnaire). Focus group interviews (n = 4) were conducted with 22 participants, to further understand students’ RPT experiences. Results There was positive improvement in attitudes to peer teaching (M = 49.2, SD = 10.0 to M = 52.3, SD = 8.2, p < 0.05, [95% CI = 0.7 to 5.4]). Knowledge scores also increased significantly (M = 6.9, SD = 2.0 to M = 9.7, SD = 1.9), p < 0.05 [95% CI = 2.3 to 3.2]. Aggregate mean knowledge scores increased more for peer teachers (M = 3.3) than they did for peer learners (M = 2.2). Thematic outcomes from focus groups indicated challenging yet beneficial journeys, collective learning outcomes, along with benefits of RPT including enhanced teaching, self-confidence, communication, and independent and collaborative learning. Conclusion This study concludes that RPT is effective in clinical skills teaching and sets a foundation for further research.
- Description: Doctor of Philosophy
Regeneration of sulfur rich amines in a combined capture system aimed to lower the cost of PCC in Australian coal fired power plants
- Authors: Garg, Bharti
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Coal is the dominant and most reliable source of energy in Australia. However, the increasing global temperatures and its impact on the climate raises concerns on the use of coal worldwide. Due to availability of abundant, cheap quality coals, Australia is researching how it and its international customers can continue to use its abundant coal resources whilst limiting greenhouse emissions. Hence, low CO2 emitting energy technologies like carbon capture and storage (CCS) have an important role to play not only in power but also the cement and steel industries Post-combustion CO2 capture (PCC), the most developed technology in CCS using aqueous amines to capture CO2, still face challenges for its large-scale commercialisation. The cost of electricity with PCC rises to almost double that produced without integrating PCC technology in new power stations. The retrofit of PCC technology into existing power stations is very site specific and costs can be around half of the cost of building a new power plant. Apart from this, the implementation of PCC poses an energy penalty to the power station as the efficiency of the plant can drop almost by 10-11% due to the increased solvent heating and CO2 compression loads. Particularly with the nations like Australia, the cost of PCC installation is even higher as there are no flue gas desulfurisation (FGD) units in Australian power stations. The presence of harmful gases like SO2 in coal-fired power plant flue gases affect CO2 capture performance during PCC due to the higher affinity of amines to absorb stronger acidic gases against CO2 which is a weaker acid gas than SO2. These stronger acidic gases tend to form heat stable salts with the absorbent amines used to capture CO2 . Heat stable salts refer to the thermally non-regenerable protonated amines which are usually produced when the amine solution is contaminated by organic acids (Weiland et al., 2004). Hence, the bonded amine is not available for CO2 capture, increasing the requirement for makeup amine resulting in higher operating cost. Therefore, FGD units are an essential requirement before the installation of PCC facilities in a coal-fired power station. This results in a levelised cost of electricity in Australian power plants that is high compared to nations which have FGD installed in their power stations. CSIRO has developed a combined capture process to simultaneously capture CO2 and SO2 from Australian power plant flue gases using a single amine absorbent in order to lower the cost of PCC installation in Australia. The process generates a unique sulfur rich amine absorbent which needs regeneration. This thesis investigates various amine regeneration processes, using MEA as a reference, and their commercial viability to the CS-Cap process. Due to the unique nature of the sulfur rich absorbent generated in the CS-Cap process, its amine is recoverable through many other regeneration processes besides standard thermal reclamation. My thesis investigates the effectiveness of regeneration techniques like Ion exchange, Electro-dialysis, Crystallisation, Nano-filtration in regenerating the sulfur rich amine. Initially the theoretical investigation was carried as a part of literature review and further a brief exploratory laboratory scale evaluation of the most suited technologies was carried out. The results obtained from laboratory scale experimentation were fed to an Aspen Plus simulation model in order to understand the behaviour of the system under various operating conditions. Further a cost estimation was carried out in order to produce a high level cost for the selected regeneration technologies in the CS-Cap process. The cost of the regeneration technologies were further integrated into the overall CO2 capture process in order to compare the cost of standard FGD + PCC process against the CS-Cap process which answers the broader research question whether the CS-Cap process will be economical for Australian coal power plants. Overall this thesis reveals the effectiveness of various technologies in regenerating sulfur rich amines. It suggests CSIRO’s patented CS-Cap process is a cost-effective approach for capturing CO2 from Australian coal fired power plants despite its sensitivity to regeneration cost.
- Description: Doctor of Philosophy
- Authors: Garg, Bharti
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Coal is the dominant and most reliable source of energy in Australia. However, the increasing global temperatures and its impact on the climate raises concerns on the use of coal worldwide. Due to availability of abundant, cheap quality coals, Australia is researching how it and its international customers can continue to use its abundant coal resources whilst limiting greenhouse emissions. Hence, low CO2 emitting energy technologies like carbon capture and storage (CCS) have an important role to play not only in power but also the cement and steel industries Post-combustion CO2 capture (PCC), the most developed technology in CCS using aqueous amines to capture CO2, still face challenges for its large-scale commercialisation. The cost of electricity with PCC rises to almost double that produced without integrating PCC technology in new power stations. The retrofit of PCC technology into existing power stations is very site specific and costs can be around half of the cost of building a new power plant. Apart from this, the implementation of PCC poses an energy penalty to the power station as the efficiency of the plant can drop almost by 10-11% due to the increased solvent heating and CO2 compression loads. Particularly with the nations like Australia, the cost of PCC installation is even higher as there are no flue gas desulfurisation (FGD) units in Australian power stations. The presence of harmful gases like SO2 in coal-fired power plant flue gases affect CO2 capture performance during PCC due to the higher affinity of amines to absorb stronger acidic gases against CO2 which is a weaker acid gas than SO2. These stronger acidic gases tend to form heat stable salts with the absorbent amines used to capture CO2 . Heat stable salts refer to the thermally non-regenerable protonated amines which are usually produced when the amine solution is contaminated by organic acids (Weiland et al., 2004). Hence, the bonded amine is not available for CO2 capture, increasing the requirement for makeup amine resulting in higher operating cost. Therefore, FGD units are an essential requirement before the installation of PCC facilities in a coal-fired power station. This results in a levelised cost of electricity in Australian power plants that is high compared to nations which have FGD installed in their power stations. CSIRO has developed a combined capture process to simultaneously capture CO2 and SO2 from Australian power plant flue gases using a single amine absorbent in order to lower the cost of PCC installation in Australia. The process generates a unique sulfur rich amine absorbent which needs regeneration. This thesis investigates various amine regeneration processes, using MEA as a reference, and their commercial viability to the CS-Cap process. Due to the unique nature of the sulfur rich absorbent generated in the CS-Cap process, its amine is recoverable through many other regeneration processes besides standard thermal reclamation. My thesis investigates the effectiveness of regeneration techniques like Ion exchange, Electro-dialysis, Crystallisation, Nano-filtration in regenerating the sulfur rich amine. Initially the theoretical investigation was carried as a part of literature review and further a brief exploratory laboratory scale evaluation of the most suited technologies was carried out. The results obtained from laboratory scale experimentation were fed to an Aspen Plus simulation model in order to understand the behaviour of the system under various operating conditions. Further a cost estimation was carried out in order to produce a high level cost for the selected regeneration technologies in the CS-Cap process. The cost of the regeneration technologies were further integrated into the overall CO2 capture process in order to compare the cost of standard FGD + PCC process against the CS-Cap process which answers the broader research question whether the CS-Cap process will be economical for Australian coal power plants. Overall this thesis reveals the effectiveness of various technologies in regenerating sulfur rich amines. It suggests CSIRO’s patented CS-Cap process is a cost-effective approach for capturing CO2 from Australian coal fired power plants despite its sensitivity to regeneration cost.
- Description: Doctor of Philosophy
Rethinking english language support : reflections from chinese international students on communicating orally in english in the study abroad context
- Authors: Pruis, Karen
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Australian universities are currently emphasizing such graduate qualities as English language proficiency. However, this can be problematic for many international students who may still be struggling to communicate orally in English while participating in their chosen course of study. Indeed, the English language proficiency of international students has often received negative attention from the Australian media, employers, and academics. Several government reviews have recommended ongoing English language support for international students that extends beyond existing English language entry requirements, English Academic Preparation programs, and Post-entry Language Assessments. At the same time, there has been a critique of responses to these issues which focus on language proficiency—and simply place the onus on international students to increase their English language proficiency—without taking issues of intercultural communicative competence into account, along with calls for institutional frameworks to better support student experience. This thesis is one contribution to this debate, supported and informed by an exploration of lived experiences of Chinese students engaging with oral English language use and other supports. Not only are Chinese students the largest cohort of international students in Australia, but English education in China also does not appear to prepare them effectively to communicate orally in English. Very different sociocultural backgrounds can also make it difficult for this cohort to engage both academically and socially in Australian higher education. These issues comprise road blockers that can limit English language practice opportunities and negatively affect academic success. iii This thesis shines a light on this cohort’s oral English language experiences in the study abroad context via engagement of Max van Manen’s (1990, 2014) frameworks for phenomenologically oriented qualitative research. Drawing on the lived experiences of Chinese students and a critical review of the regulatory frameworks that inform sectoral and institutional English language proficiency models, this thesis argues for an English language proficiency support framework that integrates insights from intercultural communicative competence into oral English language proficiency as well as the development of curriculum, course delivery, and assessments.
- Description: Doctor of Philosophy
- Authors: Pruis, Karen
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Australian universities are currently emphasizing such graduate qualities as English language proficiency. However, this can be problematic for many international students who may still be struggling to communicate orally in English while participating in their chosen course of study. Indeed, the English language proficiency of international students has often received negative attention from the Australian media, employers, and academics. Several government reviews have recommended ongoing English language support for international students that extends beyond existing English language entry requirements, English Academic Preparation programs, and Post-entry Language Assessments. At the same time, there has been a critique of responses to these issues which focus on language proficiency—and simply place the onus on international students to increase their English language proficiency—without taking issues of intercultural communicative competence into account, along with calls for institutional frameworks to better support student experience. This thesis is one contribution to this debate, supported and informed by an exploration of lived experiences of Chinese students engaging with oral English language use and other supports. Not only are Chinese students the largest cohort of international students in Australia, but English education in China also does not appear to prepare them effectively to communicate orally in English. Very different sociocultural backgrounds can also make it difficult for this cohort to engage both academically and socially in Australian higher education. These issues comprise road blockers that can limit English language practice opportunities and negatively affect academic success. iii This thesis shines a light on this cohort’s oral English language experiences in the study abroad context via engagement of Max van Manen’s (1990, 2014) frameworks for phenomenologically oriented qualitative research. Drawing on the lived experiences of Chinese students and a critical review of the regulatory frameworks that inform sectoral and institutional English language proficiency models, this thesis argues for an English language proficiency support framework that integrates insights from intercultural communicative competence into oral English language proficiency as well as the development of curriculum, course delivery, and assessments.
- Description: Doctor of Philosophy
Rule-based interactive assisted reinforcement learning
- Authors: Bignold, Adam
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Reinforcement Learning (RL) has seen increasing interest over the past few years, partially owing to breakthroughs in the digestion and application of external information. The use of external information results in improved learning speeds and solutions to more complex domains. This thesis, a collection of five key contributions, demonstrates that comparable performance gains to existing Interactive Reinforcement Learning methods can be achieved using less data, sourced during operation, and without prior verifcation and validation of the information's integrity. First, this thesis introduces Assisted Reinforcement Learning (ARL), a collective term referring to RL methods that utilise external information to leverage the learning process, and provides a non-exhaustive review of current ARL methods. Second, two advice delivery methods common in ARL, evaluative and informative, are compared through human trials. The comparison highlights how human engagement, accuracy of advice, agent performance, and advice utility differ between the two methods. Third, this thesis introduces simulated users as a methodology for testing and comparing ARL methods. Simulated users enable testing and comparing of ARL systems without costly and time-consuming human trials. While not a replacement for well-designed human trials, simulated users offer a cheap and robust approach to ARL design and comparison. Fourth, the concept of persistence is introduced to Interactive Reinforcement Learning. The retention and reuse of advice maximises utility and can lead to improved performance and reduced human demand. Finally, this thesis presents rule-based interactive RL, an iterative method for providing advice to an agent. Existing interactive RL methods rely on constant human supervision and evaluation, requiring a substantial commitment from the advice-giver. Rule-based advice can be provided proactively and be generalised over the state-space while remaining flexible enough to handle potentially inaccurate or irrelevant information. Ultimately, the thesis contributions are validated empirically and clearly show that rule-based advice signicantly reduces human guidance requirements while improving agent performance.
- Description: Doctor of Pholosophy
- Authors: Bignold, Adam
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Reinforcement Learning (RL) has seen increasing interest over the past few years, partially owing to breakthroughs in the digestion and application of external information. The use of external information results in improved learning speeds and solutions to more complex domains. This thesis, a collection of five key contributions, demonstrates that comparable performance gains to existing Interactive Reinforcement Learning methods can be achieved using less data, sourced during operation, and without prior verifcation and validation of the information's integrity. First, this thesis introduces Assisted Reinforcement Learning (ARL), a collective term referring to RL methods that utilise external information to leverage the learning process, and provides a non-exhaustive review of current ARL methods. Second, two advice delivery methods common in ARL, evaluative and informative, are compared through human trials. The comparison highlights how human engagement, accuracy of advice, agent performance, and advice utility differ between the two methods. Third, this thesis introduces simulated users as a methodology for testing and comparing ARL methods. Simulated users enable testing and comparing of ARL systems without costly and time-consuming human trials. While not a replacement for well-designed human trials, simulated users offer a cheap and robust approach to ARL design and comparison. Fourth, the concept of persistence is introduced to Interactive Reinforcement Learning. The retention and reuse of advice maximises utility and can lead to improved performance and reduced human demand. Finally, this thesis presents rule-based interactive RL, an iterative method for providing advice to an agent. Existing interactive RL methods rely on constant human supervision and evaluation, requiring a substantial commitment from the advice-giver. Rule-based advice can be provided proactively and be generalised over the state-space while remaining flexible enough to handle potentially inaccurate or irrelevant information. Ultimately, the thesis contributions are validated empirically and clearly show that rule-based advice signicantly reduces human guidance requirements while improving agent performance.
- Description: Doctor of Pholosophy
Seeds, soils and moisture : ecophysiology to inform mine site restoration in arid zones
- Authors: Duncan, Corrine
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Mining in arid regions of Australia is followed by restoration and rehabilitation efforts. However, attempts to reintroduce many woody plant species have been unsuccessful. Water is the key limiting resource to plant growth and seed germination in arid zones. In this thesis, I investigated ecophysiological processes that may help improve recruitment across novel arid landscapes. I tested seed traits and dormancy cues of eight keystone plants and found that six of them had non-dormant, rapidly germinating seeds; a trait we propose is an adaptation to the region’s unpredictable rainfall. To identify the germination niche of species, I incubated seeds under different temperatures and water potentials, and found drought avoidance to be an important survival strategy for arid species. I collected soil samples to compare biophysicochemical properties of reconstructed soils to remnant ecosystems, and found that the distribution of clay content in the reconstructed soils did not mirror the remnant soils, compromising their ability to sustain perennial vegetation. I also monitored soil moisture and found that soil reconstruction reduces rainfall infiltration and retention, and subsequently increases evaporation. The synthesis of these results demonstrate some of the limitations to successful restoration in these systems, such as (1) unknown dormancy cues and poor seed longevity, (2) infrequent and episodic plant recruitment due to water limitation, and (3) reduced hydrological function of reconstructed soils. The failure to reinstate hydrological function is the major constraint to ecological restoration in this arid zone. Nonetheless, results from this study suggest that restoration is possible through more strategic use of seed, careful selection of drought tolerant species, and increasing soil moisture. Further failures to reinstate ecosystem function and community dynamics in arid zones with reconstructed soils can be prevented by understanding the edaphic constraints to plant establishment, and ameliorating conditions to mimic ecohydrological processes in remnant ecosystems.
- Description: Doctor of Philosophy
- Authors: Duncan, Corrine
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Mining in arid regions of Australia is followed by restoration and rehabilitation efforts. However, attempts to reintroduce many woody plant species have been unsuccessful. Water is the key limiting resource to plant growth and seed germination in arid zones. In this thesis, I investigated ecophysiological processes that may help improve recruitment across novel arid landscapes. I tested seed traits and dormancy cues of eight keystone plants and found that six of them had non-dormant, rapidly germinating seeds; a trait we propose is an adaptation to the region’s unpredictable rainfall. To identify the germination niche of species, I incubated seeds under different temperatures and water potentials, and found drought avoidance to be an important survival strategy for arid species. I collected soil samples to compare biophysicochemical properties of reconstructed soils to remnant ecosystems, and found that the distribution of clay content in the reconstructed soils did not mirror the remnant soils, compromising their ability to sustain perennial vegetation. I also monitored soil moisture and found that soil reconstruction reduces rainfall infiltration and retention, and subsequently increases evaporation. The synthesis of these results demonstrate some of the limitations to successful restoration in these systems, such as (1) unknown dormancy cues and poor seed longevity, (2) infrequent and episodic plant recruitment due to water limitation, and (3) reduced hydrological function of reconstructed soils. The failure to reinstate hydrological function is the major constraint to ecological restoration in this arid zone. Nonetheless, results from this study suggest that restoration is possible through more strategic use of seed, careful selection of drought tolerant species, and increasing soil moisture. Further failures to reinstate ecosystem function and community dynamics in arid zones with reconstructed soils can be prevented by understanding the edaphic constraints to plant establishment, and ameliorating conditions to mimic ecohydrological processes in remnant ecosystems.
- Description: Doctor of Philosophy
Taking fire, making fire : settler colonial understandings of Aboriginal fire practices in Victoria, Australia
- Authors: McMaster, Sarah
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: In the State of Victoria, Australia, fire has a political dimension that is as vigorous and enduring as its physical presence. This thesis argues that in Victoria, European explorers and settler colonists persistently treated and depicted Aboriginal fire skills and practices in ways that were politically advantageous to themselves, and disadvantageous to Aboriginal peoples. Drawing from nineteenth century diaries, letters, recollections, newspaper articles and official records, this work uses Foucauldian theories to analyse the discourses that shaped and made possible the newcomers’ understandings of Aboriginal fire practices. It argues that explorers and settler colonists sought to replace Aboriginal peoples as Victoria’s fire managers and to restrict the opportunities Aboriginal peoples had to determine burning regimes. They did this physically, by prohibiting, and limiting attempts by Aboriginal peoples to continue precolonial fire practices. They also did it discursively, creating knowledge which constituted the practices as antiquated and incompatible with colonial enterprises, and by forming their own identity as expert settler Victorians, legitimately at home on the land. This thesis stresses that relationships of power between Aboriginal and European peoples were multidimensional and argues that in maintaining a position of dominance, the newcomers variously appropriated, emulated, feared and revered Aboriginal fire practices. It further argues that these efforts to disturb Aboriginal peoples using fire were fuelled only partially by the settler colonial perceptions that Aboriginal-managed fires presented unacceptable physical risks to humans and their assets. Efforts to disturb existing practices were additionally prompted by the newcomers’ political need to effect their seizure of territory, by demonstrating that it was they, not Aboriginal peoples, who controlled fire in Victoria. Drawing from settler colonial theory about the enduring nature of colonising structures and discourse, this thesis suggests that caution is needed to ensure the state’s contemporary use of Aboriginal fire practices does not further perpetuate settler colonial patterns of dominance and control.
- Description: Doctor of Philosophy
- Authors: McMaster, Sarah
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: In the State of Victoria, Australia, fire has a political dimension that is as vigorous and enduring as its physical presence. This thesis argues that in Victoria, European explorers and settler colonists persistently treated and depicted Aboriginal fire skills and practices in ways that were politically advantageous to themselves, and disadvantageous to Aboriginal peoples. Drawing from nineteenth century diaries, letters, recollections, newspaper articles and official records, this work uses Foucauldian theories to analyse the discourses that shaped and made possible the newcomers’ understandings of Aboriginal fire practices. It argues that explorers and settler colonists sought to replace Aboriginal peoples as Victoria’s fire managers and to restrict the opportunities Aboriginal peoples had to determine burning regimes. They did this physically, by prohibiting, and limiting attempts by Aboriginal peoples to continue precolonial fire practices. They also did it discursively, creating knowledge which constituted the practices as antiquated and incompatible with colonial enterprises, and by forming their own identity as expert settler Victorians, legitimately at home on the land. This thesis stresses that relationships of power between Aboriginal and European peoples were multidimensional and argues that in maintaining a position of dominance, the newcomers variously appropriated, emulated, feared and revered Aboriginal fire practices. It further argues that these efforts to disturb Aboriginal peoples using fire were fuelled only partially by the settler colonial perceptions that Aboriginal-managed fires presented unacceptable physical risks to humans and their assets. Efforts to disturb existing practices were additionally prompted by the newcomers’ political need to effect their seizure of territory, by demonstrating that it was they, not Aboriginal peoples, who controlled fire in Victoria. Drawing from settler colonial theory about the enduring nature of colonising structures and discourse, this thesis suggests that caution is needed to ensure the state’s contemporary use of Aboriginal fire practices does not further perpetuate settler colonial patterns of dominance and control.
- Description: Doctor of Philosophy
- Authors: Strachan, Shirley
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text: false
- Description: This PhD is the first prosopographical study of two generations of Australian manual healers in the twentieth century. The central historical figure is Thomas Ambrose Bowen (1916-1982) a self-titled Australian osteopath and arguably a therapeutic genius turned victim of health politics of the twentieth century. Bowen was stripped of his osteopathic identity as a result of political machinations that occurred during regulation of the industry in the late-1970s and early-1980s. This thesis reveals the legitimacy of Bowen’s claim to osteopathic stature and how his career is representative of the experience of a number of osteopaths during regulation of chiropractic and osteopathy. Bowen’s career was obscured in two respects. Firstly, in the lead up to the Chiropractors and Osteopaths Act 1978, overseas educated interests sought to disenfranchise Australian practitioners. This was offset by a successful response from the Australian chiropractic lobby. Secondly, posthumous commercial popularisation of Bowen’s claimed work, absent observer consensus and historical research, has further served to obfuscate Bowen’s prowess and marginalised his legacy. This thesis is the first to link Bowen’s practice to the influence of F G Roberts, an early Australian pioneer of naturopathic osteopathy. It explores Bowen’s emergence from a network of prominent football masseurs to his professional engagement with osteopathic advocates. This thesis is the first historical study to present the clinical life and times of Bowen among his contemporaries. In doing so it examines his broader significance as a consummate Australian osteopath. New historical narratives founded on extensive primary sources, oral histories as well as discourse analysis, ethnography, biography, hermeneutics and cultural mapping are used to place Bowen in context with his peers on the Australian osteopathic stage. Posthumous narratives that underpin commercial global marketing are challenged to the extent they obscure a clear historical view of Bowen and his marginalised contemporaries as unique actors in their struggle for recognition
- Description: Doctor of Philosophy
The impacts of climate change on trade and foreign direct investment flows
- Authors: Barua, Suborna
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: A growing body of climate economics research suggests that climate change affects production, prices, distribution structures, investments and national income. Studies further describe international trade and climate related investments as key activities in climate impact mitigation and adaptation. However, despite its increasing relevance, the empirical link between climate change and international trade and investment remains largely unexplored. This thesis investigates the climate change impacts on trade and foreign direct investment (FDI) flows using static and dynamic panel estimations covering 102 countries. The modelling uses temperature and precipitation variability to separately evaluate changes in international trade from 1962 to 2014, and in FDI inflows from 1995 to 2014. The trade impacts estimations consider exports of total merchandise, agriculture and six agricultural sectors; while controlling for income, comparative advantage, productivity, domestic and trade policies, and climate zones. The FDI impacts modelling evaluates total and sectoral inflows, while controlling for income, market size, infrastructure, openness, financial development, the global financial crisis and climate zones. Results show that climate change significantly affects both exports and FDI inflows. In particular, temperature affects merchandise exports, negatively at the global and developing country level, and positively in high-income countries. Agricultural exports are negatively affected by temperature. At the sectoral level, oil-seeds and dairy are mostly affected. Precipitation effects are limited and mostly negative for agriculture. The FDI world aggregate flows respond mostly positively to both temperature and precipitation, and static estimations indicate a FDI positive response in developing countries. Furthermore, FDI sectoral estimations indicate a differentiated response. Findings could inform the formulation of trade and investment policies, at the national and global level, in consideration to the differential impacts of climate change across sectors, regions and economic status. Furthermore, these estimates could be used in projections considering climate change as a determinant of trade and investment flows.
- Description: Doctor of Philosophy
- Authors: Barua, Suborna
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: A growing body of climate economics research suggests that climate change affects production, prices, distribution structures, investments and national income. Studies further describe international trade and climate related investments as key activities in climate impact mitigation and adaptation. However, despite its increasing relevance, the empirical link between climate change and international trade and investment remains largely unexplored. This thesis investigates the climate change impacts on trade and foreign direct investment (FDI) flows using static and dynamic panel estimations covering 102 countries. The modelling uses temperature and precipitation variability to separately evaluate changes in international trade from 1962 to 2014, and in FDI inflows from 1995 to 2014. The trade impacts estimations consider exports of total merchandise, agriculture and six agricultural sectors; while controlling for income, comparative advantage, productivity, domestic and trade policies, and climate zones. The FDI impacts modelling evaluates total and sectoral inflows, while controlling for income, market size, infrastructure, openness, financial development, the global financial crisis and climate zones. Results show that climate change significantly affects both exports and FDI inflows. In particular, temperature affects merchandise exports, negatively at the global and developing country level, and positively in high-income countries. Agricultural exports are negatively affected by temperature. At the sectoral level, oil-seeds and dairy are mostly affected. Precipitation effects are limited and mostly negative for agriculture. The FDI world aggregate flows respond mostly positively to both temperature and precipitation, and static estimations indicate a FDI positive response in developing countries. Furthermore, FDI sectoral estimations indicate a differentiated response. Findings could inform the formulation of trade and investment policies, at the national and global level, in consideration to the differential impacts of climate change across sectors, regions and economic status. Furthermore, these estimates could be used in projections considering climate change as a determinant of trade and investment flows.
- Description: Doctor of Philosophy
The making and placing of a personal view : Questions of place
- Authors: Farago, Anna
- Date: 2019
- Type: Text , Thesis , Masters
- Full Text:
- Description: The Making and Placing of a Personal View: Questions of Place uses various making methods to explore both the artist’s and others personal connection to place. The research investigates the intersection of memory, identity, and place. Memory is what informs personal history and collective futures. Identity, for the artist is as daughter, sister, mother, wife, friend, crafter, artist, woman and now widow. For others involved in the research, it is as Indigenous Elders, rangers and locals connected to specific sites. Place as which grounds and locates memories and landscapes that preoccupy the creative works. Memory and identity is explored materially through making, connecting art to place using craft’s historical connection with domestic and natural environments. Using the postmodern feminist geography of Doreen Massey, place is a site of flow and routes, rather than origins and roots. The relation between art and Massey’s notion of place is investigated as sympathetic to craft as a feminine epistemology. The creative work created comprises of four large textile patchworks, a series of small embroideries, and a pair of gouache paintings. The making of three large patchwork banner works were informed by conversational interviews conducted with Indigenous and non-Indigenous rangers. The banner works were installed for the duration of a weekend in Darebin Parklands in Alphington, Victoria in 2016 and at Pigeon House Mountain Didthul, Morton National Park, NSW in 2017. Performative and documentation photographs and videos were created in response to these installations. In addition a hand-stitched patchwork was slowly constructed over a year of grief and then used as a cloak and protective cloth in directed performative photos shot in the garden and on the roof of the artist’s home.
- Description: Masters by Research
- Authors: Farago, Anna
- Date: 2019
- Type: Text , Thesis , Masters
- Full Text:
- Description: The Making and Placing of a Personal View: Questions of Place uses various making methods to explore both the artist’s and others personal connection to place. The research investigates the intersection of memory, identity, and place. Memory is what informs personal history and collective futures. Identity, for the artist is as daughter, sister, mother, wife, friend, crafter, artist, woman and now widow. For others involved in the research, it is as Indigenous Elders, rangers and locals connected to specific sites. Place as which grounds and locates memories and landscapes that preoccupy the creative works. Memory and identity is explored materially through making, connecting art to place using craft’s historical connection with domestic and natural environments. Using the postmodern feminist geography of Doreen Massey, place is a site of flow and routes, rather than origins and roots. The relation between art and Massey’s notion of place is investigated as sympathetic to craft as a feminine epistemology. The creative work created comprises of four large textile patchworks, a series of small embroideries, and a pair of gouache paintings. The making of three large patchwork banner works were informed by conversational interviews conducted with Indigenous and non-Indigenous rangers. The banner works were installed for the duration of a weekend in Darebin Parklands in Alphington, Victoria in 2016 and at Pigeon House Mountain Didthul, Morton National Park, NSW in 2017. Performative and documentation photographs and videos were created in response to these installations. In addition a hand-stitched patchwork was slowly constructed over a year of grief and then used as a cloak and protective cloth in directed performative photos shot in the garden and on the roof of the artist’s home.
- Description: Masters by Research
The molecular characterisation of shigella spp. from Papua New Guinea and Pacific Island Nations
- Authors: Malau, Elisheba
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: In Papua New Guinea (PNG) and other low-middle income countries (LMICs) in Oceania, diarrhoea remains a leading cause of hospitalisation and death in children <5 years old; and is an important cause of illness in older children and adults. Shigella is one of four leading causes of diarrhoea globally and is likely a major cause of diarrhoea in Oceanic LMICs, particularly PNG. A survey was conducted among parents of children with diarrhoea in the PNG highlands, demonstrating limited access to, and application of, sanitation and hygiene; likely contributing to the transmission of Shigella and other pathogens in PNG. To better understand Shigella in Oceanic LMICs, multiple analyses of isolates from within PNG (n=38), far-northeastern Australia, and from travellers returning to Australia from Oceanic LMICs with shigellosis (n=34) were conducted. Antimicrobial susceptibility (by disc diffusion), detection of virulence genes by polymerase chain reaction (PCR) were conducted on all isolates, and whole genome sequencing (WGS) conducted on 63 isolates. Shigella spp. were commonly resistant to two or more classes of first-line antibiotics, with resistance more common in post-2010 relative to pre-2010 isolates. WGS was used to verify PCR detection of virulence genes, determine whether resistance could be predicted genetically, and conduct phylogenetic analysis of Shigella spp. in Oceania. WGS surpassed PCR in the detection of virulence genes, but correlated poorly with phenotypic antimicrobial resistance. Phylogenetic analysis revealed the intra- and inter-country relatedness. Three phylogenetic groups of S. flexneri co-exist in Oceanic LMICs (and far-northeastern Australia), the result of multiple incursions. Two lineages of S. sonnei were detected, one circulating in PNG and New Caledonia, and the other in various other countries including Fiji; with no geographical overlap of the two S. sonnei lineages. Incursions of Shigella into the Oceanic LMICs occur regularly, and are likely to occur again. This study provides evidence of the need for, and potential approach to, expanded surveillance of Shigella in the region.
- Description: Doctor of Philsophy
- Authors: Malau, Elisheba
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: In Papua New Guinea (PNG) and other low-middle income countries (LMICs) in Oceania, diarrhoea remains a leading cause of hospitalisation and death in children <5 years old; and is an important cause of illness in older children and adults. Shigella is one of four leading causes of diarrhoea globally and is likely a major cause of diarrhoea in Oceanic LMICs, particularly PNG. A survey was conducted among parents of children with diarrhoea in the PNG highlands, demonstrating limited access to, and application of, sanitation and hygiene; likely contributing to the transmission of Shigella and other pathogens in PNG. To better understand Shigella in Oceanic LMICs, multiple analyses of isolates from within PNG (n=38), far-northeastern Australia, and from travellers returning to Australia from Oceanic LMICs with shigellosis (n=34) were conducted. Antimicrobial susceptibility (by disc diffusion), detection of virulence genes by polymerase chain reaction (PCR) were conducted on all isolates, and whole genome sequencing (WGS) conducted on 63 isolates. Shigella spp. were commonly resistant to two or more classes of first-line antibiotics, with resistance more common in post-2010 relative to pre-2010 isolates. WGS was used to verify PCR detection of virulence genes, determine whether resistance could be predicted genetically, and conduct phylogenetic analysis of Shigella spp. in Oceania. WGS surpassed PCR in the detection of virulence genes, but correlated poorly with phenotypic antimicrobial resistance. Phylogenetic analysis revealed the intra- and inter-country relatedness. Three phylogenetic groups of S. flexneri co-exist in Oceanic LMICs (and far-northeastern Australia), the result of multiple incursions. Two lineages of S. sonnei were detected, one circulating in PNG and New Caledonia, and the other in various other countries including Fiji; with no geographical overlap of the two S. sonnei lineages. Incursions of Shigella into the Oceanic LMICs occur regularly, and are likely to occur again. This study provides evidence of the need for, and potential approach to, expanded surveillance of Shigella in the region.
- Description: Doctor of Philsophy
The molecular epidemiology of influenza in Cambodia
- Authors: Suttie, Annika
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Avian influenza viruses (AIVs) represent a risk to the health of humans and animals. The prevalence of AIVs in live bird markets in Cambodia is among the highest in the world, being detected in 45.5% of tested poultry in 2015. To better understand the potential risk presented by AIVs, this thesis investigated the genetic characteristics of AIVs circulating in Cambodia between 2014 to 2018; focusing on subtypes that pose the greatest risk to human and animal health (H5, H7 and H9). Highly pathogenic (HP) H5N1 clade 2.3.2.1c viruses and low pathogenic H9N2 BJ/94-like h9-4.2.5 clade viruses were the most frequently detected subtypes, and circulate endemically in Cambodia’s domestic poultry. Co-infections were detected and facilitated the production of two novel reassortant H5N1 AIVs with single genes from H9N2 viruses. Additionally, numerous intrasubtypic reassortment events were detected for H5 and H9 AIVs. This is concerning as reassortment events can rapidly produce novel viruses of public health risk. Phylogenetic analyses showed some genes of the Cambodian H5, H7 and H9 AIVs clustered with zoonotic viruses, suggesting a common origin. There are parallels between H5N1 and H9N2 AIVs detected in Cambodia and Vietnam, likely facilitated through the illegal trade of live poultry and/or the migration of wild birds. Molecular analyses showed H9 AIVs have major markers associated with adaptation to mammals; though during the study period the only human AIV cases were the result of HP H5N1. Molecular markers of resistance to adamantine antivirals was observed in 3% of H5 and 41% of H9 AIVs; however, both subtypes remain susceptible to first line antiviral treatment, neuraminidase inhibitors. The data presented in this thesis demonstrates that circulation of Cambodian AIVs represents a risk for the emergence of novel viruses. Interventions are urgently needed to mitigate the threat posed to poultry and humans.
- Description: Doctor of Philosophy
- Authors: Suttie, Annika
- Date: 2019
- Type: Text , Thesis , PhD
- Full Text:
- Description: Avian influenza viruses (AIVs) represent a risk to the health of humans and animals. The prevalence of AIVs in live bird markets in Cambodia is among the highest in the world, being detected in 45.5% of tested poultry in 2015. To better understand the potential risk presented by AIVs, this thesis investigated the genetic characteristics of AIVs circulating in Cambodia between 2014 to 2018; focusing on subtypes that pose the greatest risk to human and animal health (H5, H7 and H9). Highly pathogenic (HP) H5N1 clade 2.3.2.1c viruses and low pathogenic H9N2 BJ/94-like h9-4.2.5 clade viruses were the most frequently detected subtypes, and circulate endemically in Cambodia’s domestic poultry. Co-infections were detected and facilitated the production of two novel reassortant H5N1 AIVs with single genes from H9N2 viruses. Additionally, numerous intrasubtypic reassortment events were detected for H5 and H9 AIVs. This is concerning as reassortment events can rapidly produce novel viruses of public health risk. Phylogenetic analyses showed some genes of the Cambodian H5, H7 and H9 AIVs clustered with zoonotic viruses, suggesting a common origin. There are parallels between H5N1 and H9N2 AIVs detected in Cambodia and Vietnam, likely facilitated through the illegal trade of live poultry and/or the migration of wild birds. Molecular analyses showed H9 AIVs have major markers associated with adaptation to mammals; though during the study period the only human AIV cases were the result of HP H5N1. Molecular markers of resistance to adamantine antivirals was observed in 3% of H5 and 41% of H9 AIVs; however, both subtypes remain susceptible to first line antiviral treatment, neuraminidase inhibitors. The data presented in this thesis demonstrates that circulation of Cambodian AIVs represents a risk for the emergence of novel viruses. Interventions are urgently needed to mitigate the threat posed to poultry and humans.
- Description: Doctor of Philosophy