Open Access Theses

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Access status: Open Access ,
Crystallographic Anisotropy and its Influence on Ion Track Morphology in Single-Crystalline Materials
(2026) Wierbik, Jessica
Trace amounts of actinides incorporated into minerals such as apatite, mica, and zircon undergo spontaneous fission, producing energetic fragments that form narrow cylindrical damage zones a few nanometres in diameter known as fission tracks (FTs). Thermal annealing of these tracks is widely used in FT thermochronology to reconstruct low-temperature thermal histories of rocks and estimate rates of geological processes within the upper crust. Current FT dating relies on chemical etching to enlarge tracks to the micron scale, but this removes the primary radiation damage, obscuring information about the actual damaged region. A detailed understanding of unetched track damage and its evolution under geologically relevant conditions is therefore essential for improving the reliability of FT thermochronology. When crystalline solids are irradiated with swift heavy ions (SHIs), the formation of ion tracks is similar to that of FTs, making them well suited as a proxy to study the parameters controlling FT morphology. Ion tracks are conventionally described as cylindrical damage zones with circular cross-sections. This view, however, largely reflects limitations of existing characterisation techniques in resolving fine cross-sectional features. The structural anisotropy of single-crystals suggests deviations from circular track geometries should be expected, and variations in cross-sectional shape and annealing behaviour for differently oriented tracks are likely governed by the host crystal's properties. In this work, synchrotron-based small-angle X-ray scattering (SAXS) is used to resolve cross-sectional anisotropy of ion tracks at the nanometre scale. SAXS measurements using a rotational sample stage enabled determination of the full cross-sections of differently oriented tracks in single-crystalline fluorapatite, elbaite tourmaline, and synthetic alpha-quartz irradiated with 185 MeV Au ions along the [0001] and <10-10> directions. The results reveal pronounced anisotropy in both track shape and size. Tracks formed parallel to [0001] show near-circular cross-sections, whereas tracks oriented perpendicular to the c-axis exhibit distinctly non-circular cross-sections. The observed anisotropy correlates with the direction-dependent elastic properties of the host crystals, with smaller radii occurring along elastically stiffer directions. The rotational SAXS setup was further combined with ex situ thermal annealing to investigate track evolution in fluorapatite irradiated with 1.64 GeV Au ions. Annealing results in reduction of track size for both orientations. <10-10>-tracks initially show non-circular cross-sections that become increasingly anisotropic with temperature, indicating heterogeneous recovery. The strongest shrinkage occurs at the position of the hexagonal axis within the plane, where lower activation energies are required to initiate recrystallisation. Tracks parallel to [0001] retain their circular geometry and display more isotropic recovery. In situ annealing of ion tracks in tourmaline over 300-640 C shows that tracks, initially characterised by a core and surrounding transition zone, exhibit progressive narrowing of the transition zone above 460 C, indicating a sharpening of the track-matrix interface. Above 520 C, reliable density profiles can no longer be determined for either orientation. Raman measurements indicate that irradiation induces lattice disorder exceeding that expected from track overlap alone, suggesting additional damage mechanisms. Moderate annealing promotes partial lattice recovery, but above 500 C crystallinity decreases and cylindrical track models break down, indicating that host-lattice metamictisation directly affects track annealing behaviour. The results highlight the fundamental role of host crystal structure in ion-track formation and annealing, with implications extending to nuclear materials design, planetary science, nanoscale fabrication, and thermochronology.
Access status: Open Access ,
Shakespeare's Terrible Neutrality
(2026) Chen, Jiangyue
This thesis explores what I term Shakespeare's terrible neutrality, a comprehensive and impartial stance that pervades his complete works. Drawing on a close reading of Shakespeare's plays, as well as on the critical tradition from Keats, George Steiner, and contemporary Shakespeare scholars, I argue that Shakespeare's terrible neutrality lies in his refusal to take a definitive stance (and at times even in his deliberate violation of poetic justice). This neutrality enables him to gain a comprehensive understanding of the world and human experience, particularly when considered across his entire oeuvre. Through a sustained engagement with four major themes - religion, politics, love, and law - this thesis demonstrates how Shakespeare repeatedly revisits similar scenarios, motifs, and dilemmas, adjusting variables such as character traits, social contexts, and narrative structures to create a world in which both positive and negative elements coexist, while readers can clearly discern right from wrong. Causal relationships cannot be reduced to a single predictable or explanatory framework, yet events unfold in ways consistent with reality and logic, and a greater diversity of characters and narrative developments becomes possible precisely because of this terrible neutrality.
Access status: Open Access ,
Understanding Sexual Conflict and Environmental Effects on Reproductive Strategies in Mosquitofish (Gambusia holbrooki)
Akhter, Fatema
Sexual conflict is very common and is considered as a natural phenomenon, which arises when males and females show divergency in their reproductive interests. Environmental factors such as changes in temperature, salinity and water clarity can significantly influence the level of sexual conflict and can also influence the reproductive strategies of each sex. In species, such as mosquitofish (Gambusia holbrooki), where mating is frequently coercive and male harassment is intense, social interactions and environmental conditions both play critical roles in shaping reproductive outcomes. To investigate how sexual conflict and environmental factors (such as salinity, temperature, turbidity) interact to influence reproductive strategies, physiological stress, and life-history traits in males and females, I ran a set of laboratory experiments using mosquitofish. In this thesis, I present four experimental studies examining; the cost related to harassment and multiple mating (Chapter 2); the cost of fighting and sperm production (Chapter 3); the effect of turbidity on female stress level (Chapter 4); and the effect of salinity and temperature on male reproductive strategies (Chapter 5). Chapter 1 introduces the concepts of reproduction, sexual conflict and how different environmental factors can influence reproduction in fish. Chapter 2 differentiates the cost of sexual harassment and multiple mating (polyandry) in female mosquitofish (Gambusia holbrooki). In polyandrous situation both things happen simultaneously, which is why it is difficult to know which one is more expensive. I differentiated the cost by controlling the harassment level and mating rates by using three treatments. I used ablation technique to control the rate of mating. I found that female who faced more harassment, grow more slowly and produce a smaller number of eggs. Chapter 3 differentiates the cost of sperm production from the cost of male-male fighting. As both things usually happen at once, I used the ablation technique (physically cutting the gonopodia) to stop sperm transfer to the female. To find out the most expensive one, I designed three treatments with varying number of rivals and with different sperm ejaculation ability. I found that sperm production is more expensive than fighting and competing with rivals. Chapter 4 investigates the effect of turbid water on the level of male harassment and female stress level and how the level of harassment influences the female stress level. By using four types of treatment (clear water or turbid water; and one male or three males), I found that reduced water turbidity (clear water) elevates female physiological stress (cortisol level), while male harassment levels do not affect female physiological stress. My findings highlight the importance of abiotic conditions in modulating the intensity of sexual conflict. Chapter 5 explores how temperature and salinity influence male life history and reproductive traits, including sperm quantity and velocity. I designed four treatments (two temperatures and two salinity levels) and found that in saline water males produce less sperm than in freshwater and mature earlier at a smaller size. Overall, salinity has more severe effect than temperature, but when salinity and high temperature combine then the effects are more complicated.
Access status: Open Access ,
A Multifaceted Analysis of Model Generalization in Challenging Environments
(2026) Tu, Weijie
Deep learning models have become central to modern artificial intelligence systems, achieving strong performance across a wide range of visual recognition and reasoning tasks. However, deploying these models reliably in real-world environments remains challenging. In practice, models often encounter distribution shifts, produce unreliable confidence estimates, and must operate in settings where labeled data for validation or model selection are unavailable. These challenges are particularly pronounced for large vision-language and multimodal models, whose complexity and open-ended applications demand a deeper understanding of robustness, uncertainty, and model behavior beyond conventional accuracy-based evaluation. This thesis investigates how trustworthiness can be analyzed and supported in deep models, with a particular focus on vision-language systems operating under realistic conditions. The thesis first studies the robustness of deep visual and vision-language models across diverse architectures, training distributions, and fine-tuning strategies in Chapter 3. Beyond overall accuracy, the analysis examines robustness with respect to specific visual factors, out-of-distribution conditions, and the interaction between vision and language encoders. It further incorporates safety-relevant aspects such as predictive uncertainty, out-of-distribution detection, and sensitivity to 3D perturbations, revealing systematic failure modes that arise under realistic testing scenarios. Building on these findings, Chapter 4 further delves into uncertainty estimation and calibration in vision-language models. The results show that strong zero-shot performance does not necessarily imply reliable confidence and that they are not inherently well calibrated. Nevertheless, simple post-hoc calibration methods can substantially improve uncertainty estimates, even under distribution shifts, across different label spaces, and with only limited calibration data. These results demonstrate that reliable uncertainty estimation of vision language models can be achieved in practice without extensive labeled supervision. The thesis then explores how model performance can be assessed when labeled evaluation data are unavailable. Chapters 5 and 6 study the problem of ranking models without labels. Chapter 5 shows that signals derived from softmax prediction probabilities can provide informative indicators of relative model performance on unlabeled data. Chapter 6 extends this idea to large multimodal models and further investigates the role of uncertainty signals in model ranking. Finally, Chapter 7 introduces a data-centric perspective through an unsupervised dataset representation that captures semantic structure without labels, supporting reasoning about dataset similarity, training set suitability, and test set difficulty. Together, this thesis provides a unified perspective on trustworthy machine learning for deep learning models, advancing methods for understanding model generalization in challenging environments.
Access status: Open Access ,
Planning under Partial Observability and Object Discovery with Reusable Local Strategy Priors
(2026) Tang, Zikang
Partially observable online planning problems with dynamic object discovery and initially unstable identities are characterised by substantial uncertainty, strong sequential decision-making requirements, and a nontrivial exploration–execution trade-off. Network penetration provides a representative instance of this class of problems, since the agent initially lacks knowledge of the full network topology, node roles, stable identities, and exact connectivity, and must instead discover objects online, update an internal knowledge graph, and complete a target query under a limited budget. To address this setting, this thesis proposes a hierarchical online planning framework that combines knowledge-graph-based state representation, role beliefs, local subnet construction, and budgeted Monte Carlo Tree Search. To preserve local trade-offs among success probability, intermediate progress, and execution cost, the framework uses an ϵconstraint sweep to retain an approximate set of non-dominated local options rather than collapsing local decisions into a single weighted score. It further abstracts subnet-level search outcomes into action templates indexed by structural signatures in a generalized policy library, enabling cross-episode reuse of local strategies. At the global decision stage, rule-based actions, local subnet candidates, and library-retrieved candidates are aggregated within a unified selection process, while online feedback, slow forgetting, and successful trajectory replay are used to refine stored experience. Experimental results show that pure MCTS remains stronger in raw success robustness and wall-clock runtime. However, when the subnetbased framework succeeds, it often reaches terminal success in fewer interaction steps and preserves more remaining budget. Same-type policy-library transfer provides the strongest evidence for reusable local strategy priors, while cross-type transfer is useful but less reliable. Overall, the results suggest that combining local subnet search, approximate non-dominated option organisation, and abstract strategy reuse can improve interaction-level efficiency and same-type transfer in partially observable online planning problems with dynamic object discovery, while leaving computational efficiency and cross-type robustness as limitations for future work.
Access status: Open Access ,
Developmental Programming, Life-History Trade-Offs, and the Mechanisms that Drive them: Insights from Australian Skinks
(2026) Leibold, Dalton
The conditions experienced during development can have lasting, "programmatic", consequences for phenotypes and fitness. Developmental programming may be initiated through direct effects of the environment acting on the individual, or via indirect effects of the maternal environment through maternal phenotypes. The individual effects of developmental environments and maternal effects have long been appreciated, but how they interact to program phenotypes is poorly understood. Likewise, developmental effects are highly dependent on the context in which these traits are expressed, potentially differing among species with alternative life-history strategies. Consequently, recent work has aimed to characterise the mechanisms underlying developmental programming and how conserved these mechanisms are among species. Additionally, while developmental effects in early life are well-characterized, relatively few studies have followed individuals throughout the lifespan, thereby limiting our understanding of their long-term fitness consequences. The paucity of longitudinal, multi-species studies which measure life-history traits alongside physiological mechanisms is often attributed to logistical constraints - particularly the limitations of current methods for quantifying physiological biomarkers. Therefore, in my thesis, I aimed to characterize how the developmental environment and maternal effects interact to shape key life-history traits throughout the lifespan of two species with differing life-history strategies, and developed and utilized novel methods to quantify multiple physiological biomarkers of fitness. Specifically, I tested the effects of incubation temperature and maternal stress hormones (corticosterone) on the growth and survival of delicate skinks (Lampropholis delicata) and garden skinks (Lampropholis guichenoti) throughout their lifespan in naturalistic conditions. I developed a novel function assay panel utilizing flow cytometry techniques to quantify mitochondrial function and oxidative stress - which are associated with performance and survival - both early and late in life. In doing so, I aimed to address the questions: 1) Do the developmental environment and maternal effects interact to shape early-life fitness and phenotypes?; 2) Do developmental effects have programmatic effects on life-history trajectories?; 3) Are developmental effects mediated by species' life-history strategies?; and 4) Are developmental effects driven by programmatic changes in mitochondrial or oxidative physiology? My findings generally suggest that developmental conditions have important consequences for early-life fitness, but a limited role in programming long-term patterns of phenotypic variation, that life-history strategy variation among species may play a role in buffering species from developmental effects, and that mitochondrial and oxidative physiology were not the mechanisms responsible for the patterns observed. Yet, there remain alternative mechanistic pathways and ecological contexts that may reveal a more complex relationship between developmental environments and life-history trajectories, which warrants further investigation. The comprehensive design of this thesis establishes a powerful foundation for more targeted investigations of these alternative mechanisms and pathways, while the novel flow cytometry methods presented herein provide a powerful tool for mechanistic life-history studies both in the context of developmental programming and more broadly. Thus, my thesis provides important data, experimental designs, and methodological tools for additional studies of developmental programming, life-history trade-offs, and the mechanisms that drive them.
Access status: Open Access ,
Regional Kinematics of the Banda Arc Transition Zone from Seismic and Geodetic Constraints
(2026) Nugroho, Hendro
Deformation Study in the Arc-Continental Transitional Zone of the Banda Arc Inferred from Seismic and Geodetic Data Abstract Indonesia and Timor-Leste lie within an active tectonic zone where the Indo-Australian, Pacific, and Sundaland Plates converge, resulting in complex crustal deformation and high seismicity. This study characterizes deformation across the region using broadband seismic waveform data and geodetic observations from the GPS. Seismic data from a temporary 30-station broadband array (YS network) were used to investigate the 2015 Alor earthquake sequence. We computed nine CMT solutions to describe source mechanisms, using full waveform inversion across multiple frequency bands and velocity models. The analysis included hypocenter relocation, fault plane identification, and rupture direction estimation. These efforts revealed a previously unidentified fault on Alor Island, now interpreted as an active structure contributing to regional deformation and incorporated into subsequent geodetic modeling. To assess regional plate boundary reorganization, we developed a kinematic block model using over 200 GPS velocities and 492 earthquake slip vectors from the Indonesia-Australia-New Guinea collision zone. The model resolves major block motions and reveals significant variations in slip rates and rotation, particularly across the New Guinea Fold-and-Thrust Belt and the Banda Arc. Elevated residuals in some regions suggest unmodeled micro-blocks or internal strain. Focusing on the Timor region, we refined the block model to define six micro-blocks based on GPS data, active fault mapping, and strain-rate analysis using a wavelet-based multiscale method. Despite the relatively low misfit in the broader regional model, results indicate that the Timor block undergoes internal deformation and cannot be treated as a single rigid body. These micro-blocks accommodate differential motion and localized strain, underscoring the island's complex tectonics. Overall, this integrated geodetic and seismic analysis advances understanding of crustal deformation and active tectonics in the Banda Arc region and informs future seismic hazard assessment.
Access status: Open Access ,
Tip of the Spear :Event Based Epidemiology
(2026) Edgeworth, Jared
This volume contains four projects as well as additional public health experiences that satisfy the competencies of the Master of Philosophy (Applied Epidemiology) that was conducted through placement at UNSW's Kirby Institutes Biosecurity Program, which features the EPIWATCH Open Source Outbreak Early Warning system. These projects contain an evaluation of the Syndromic surveillance component of EPIWATCH, completing the evaluation of a surveillance system competency as well as the minor competency of presenting at a scientific conference. An epidemiological investigation using survey data into Australian Attitudes and Behaviors related to COVID-19 public health measures including predictors for satisfaction to government's removal of mandatory isolation, which achieves the competencies of analyzing a public health data set and designing a epidemiological study. An analysis of potential outbreaks following two laboratory incidents in the United States of America using the event-based capabilities of EPIWATCH, serving to complete the competencies of conducting an epidemiological study competency as well as the minor competency of preparing a advanced draft for publication. Finally a measles outbreak investigation was conducted that occurred in early 2024 in Southeast Sydney that satisfies the competencies of investigating an acute public health problem or threat. The outbreak also satisfies the minor competences of conducting a literature review and creating a Lay Summary. The final chapter includes my additional experiences while undertaking this thesis, including teaching epidemiology to my peers as well as to graduate students. My presentations to my colleagues at the Biosecurity Program as well as my presentation to the general community at the Communicable Diseases and Immunization Conference in Brisbane in Mid-2024. The conclusions made from my projects, as well as the experiences that I was able to obtain have contributed to the wider body of research in applied epidemiology as well as to inform public health policy.
Access status: Open Access ,
Fetal Growth Measurement
(2026) Paoletti, Debra
Ultrasound assessment of the fetus in pregnancy has become an integral part of antenatal care. For ultrasound practitioners and pregnant women alike, it is difficult to imagine pregnancy care without ultrasound. The assessment of fetal growth by evaluating changes in serial measurements and haemodynamic assessment of the fetus with Doppler ultrasound have become valuable tools in obstetric management. Identification of pathologic fetal growth has become increasingly important as fetal growth restriction is associated with increased risk of adverse perinatal outcomes and when undiagnosed is a risk factor for stillbirth. Large fetuses may also complicate pregnancies, increasing risks for birth trauma and neonatal morbidity. With widespread adoption of ultrasound into obstetric practice, how to best discriminate between normal and pathological growth, which charts to reference measurements to, and when to perform the measurements remain contentious issues. With increasing emphasis placed on ultrasound measures of fetal size and Doppler parameters to identify abnormal growth and guide clinical management, it has become imperative that charts used for these measures are reliable and used consistently. Continued lack of standardisation has the potential for misdiagnosis of abnormal fetal growth, and the suitability of reference charts derived from one population for use on a different population is an unresolved issue and problematic in multiethnic populations. In this thesis I explore the origins of measurements used in ultrasound assessment of the fetus and how these are used to measure fetal growth and wellbeing. Ultrasound providers were surveyed to gain insights into current Australian practice in performing and reporting third trimester ultrasound. The performance of fetal reference charts currently used (now more than 25 years old) and recently published growth standards were evaluated in a prospective cross-sectional study of 1642 datasets. Lastly, methods to measure fetal growth velocity were assessed in a retrospective longitudinal study of 636 datasets. The exploration of the emergence of measurements used in ultrasound assessment of the fetus consolidates many disparate sources and provides a single account of the origin of fetal measurements. Survey findings reveal inconsistent third trimester reporting practices persist in Australia, with at least four different population based reference charts in current use and lack of uniformity in fetal Doppler assessment. Evaluation of fetal reference charts currently recommended by the Australasian Society of Ultrasound in Medicine and recently published Intergrowth 21st growth standards reveal discrepancies in the proportion of measurements falling below the 10th centile and above the 90th centile, suggesting these standards are not suitable for use in the Australian population. Assessment of fetal growth velocity between 20 and 36 weeks failed to demonstrate a strong relationship between reduced growth velocity and adverse neonatal outcome.These findings have several implications for clinical practice. Inconsistent third trimester reporting practices not only raises the possibility of false-positive and false-negative diagnosis of fetal growth restriction but also has the potential for conflicting diagnoses based on the providers' choice of reference chart. A consensus on which reference charts should be used in Australia would help remedy this situation, however evaluation of the recently published Intergrowth 21st growth standards indicates they are unsuitable for use in the Australian population. Adoption into clinical practice would result in a greater proportion of fetuses classified as large for gestational age, and fewer classified as small for gestational age. The absence of a strong relationship between reduced growth velocity between 20 and 36 weeks and adverse neonatal outcome implies formal reporting of fetal growth velocity is currently not warranted.
Access status: Open Access ,
"Originated on the wrong side of the blanket"? A History of Self-Government in the Australian Capital Territory to 2001
(2026) Humphries, Gary
This thesis offers a foundational history of the Legislative Assembly for the Australian Capital Territory in the context of the development of self-government. The ACT's is the most recently-created Australian polity, incorporating unique constitutional features. It faced intense community hostility to its establishment in 1989, including the election of MLAs committed to its abolition. This study charts the relationship between the unique circumstances of the new parliament's birth and infancy and the democratic political culture which developed in Canberra during its first dozen years. It argues that these disruptive conditions spawned two essential drivers in the Territory's emerging democratic development: first, growth towards constitutional and operational "normalcy", to demonstrate to sceptical citizens the benefits of responsible government and, secondly, the emergence of an idiosyncratic political culture in which minority government, with just a single exception (2004-08), became an entrenched feature and other departures from recognised political norms have emerged. As such, the thesis serves three important functions. First, it constitutes an appraisal by which the ACT community can evaluate whether their once-disparaged system of government has been a success or a failure. Secondly, it explores the extent to which the ACT experience may constitute a marker for the survival and evolution of Australia's democratic system, currently beset by voter distrust. Thirdly, it offers a (rare) Australian iteration of political "history from within" - historiography by a direct participant in the historical account.
Access status: Open Access ,
"That's where the politics comes in": Factors Influencing Policy Responses to Employment in Solomon Islands and Vanuatu
(2026) Close, Stephen
This doctoral research examines specific factors influencing two important employment policy areas differently in two Pacific states. Pacific Islanders prioritise better jobs and livelihoods for themselves and their families. However, employment in the Pacific has been described as a "wicked public policy problem" (Hassall, 2020, p. 124). Limited education, economic growth and jobs has impacts on poverty, under-development, and politics, including civil unrest. For decades overseas tertiary scholarships have been prioritised. Broader change has come from overseas labour opportunities in the last two decades. Pacific employment policy responses vary; with mixed impacts and unclear trends. External aid donors have been influential. How politics and societal interests shape Pacific employment policy in practice has been little researched. The research draws on interviews with policy stakeholders in both countries, and analyses policy documentation, academic material, budget and student data and media articles. Case studies trace policy-making from 2006/2007 to 2019 (Vanuatu Government Scholarships from 1997). Applying critical policy analysis and policy ethnography, this research identifies how politics shaped employment policy: who had power and how they used it. The case studies present multiple ways that politicians and officials responded to budget problems, political pressures and corruption, including varied approaches to distribute access. These included Solomon Islands' formalised 'Constituency Awards'; Vanuatu's enforced sanctions on personalised selection of scholarships; different results of attempted student loan schemes; and inception of two contrasting national universities. In Solomon Islands, emergent national leadership and significant donor substitution helped boost labour mobility numbers at the end of the case study period. In Vanuatu strong domestic policy leadership on labour mobility from early on led to broad participation but also policy contestation and 'problems of success'. In all four cases, significant donor influence raised questions about local policy ownership, and led to unintended consequences. Comparison of these cases reveals that important political and institutional differences shaped how and when politicians and officials were able to develop, deliver and reform policy. Different distributions of power, incentives, accountabilities, and societal interests, shaped policy decisions and pathways. Both broader and sectoral politics shaped two distinct patterns of employment policy-making in the two states. This thesis provides a rare, overdue, and contemporary understanding of the politics of policy-making on employment, a long-term, complex policy problem in Pacific states. It presents new insights into the agency of policy actors, and practical understanding of the operation and contestation of formal and informal institutions in Pacific policy-making. This research 'brings the politics back in' to build a better understanding of how public policy is developed, delivered and reformed in Pacific states, how politics affects education and employment, and how Pacific officials work across formal and informal institutions to meet demand for education and employment.
Access status: Open Access ,
Variation in human rib and femoral histology: A study of ancient and modern humans
(2026) Stewart, Tahlia
Remodelling is a process of bone renewal occurring throughout the human lifespan. Remodelling evidence is retained in bone microstructure (histology) in modern and ancient samples, providing a rich source of knowledge about human health and behaviour. However, we do not fully understand how age, biological sex, social status, and anatomical form of bones, influence human femoral and rib histology, particularly in Australia. To date, only one study examined Australian human femoral and rib histology, but none have compared Australian to medieval British samples to explore ancestral indicators of remodelling. This thesis aimed to investigate how different factors influence human rib and femoral histology, particularly in largely unexplored modern Australian samples compared to medieval British samples as a more widely studied ancestral population. Four questions were identified: (1) does human rib and femoral bone histology vary with age, sex and social status in samples of English ancestry?; (2) do modern and medieval human bone histology comparisons indicate more sedentary modern lifestyle? (3); is there variation in histological variables between serial rib sections? (4); does cortical bone histology vary in the femur and rib with distinct bone metabolic activities? The methods in this thesis were bone histomorphometry and cross-sectional geometry, where secondary osteons, Haversian canals, porosity, and cortical bone were quantified and analysed using univariate and multivariate statistics. The first thesis question found that secondary osteon densities were higher in older than middle adults in the rib, but not in the femur. Females had higher rib and femoral osteon and Haversian canal area than males. Modern ribs had higher secondary osteons densities than the medieval samples, except for the anterior femur, where this applied only to modern versus medieval low status. Rib porosity was higher in medieval low status samples, except in the anterior femur where it was higher in modern samples. Modern samples had lower rib cortical width than medieval samples. For thesis question two, a discriminant function analysis based on multivariate comparisons successfully separated medieval and modern rib and femoral bone, but there was no conclusive evidence that modern humans were more sedentary than medieval humans. Results from analyses addressing thesis question three found that there were correlations between serial pairs of rib cross-sections in most histological variables, except porosity and osteon and Haversian canal densities, suggesting that sampling ribs in different shaft areas may render different histological results depending on variables observed. For the final thesis question four it was discovered that femoral secondary osteons and Haversian canals were larger than in the rib, but they did not necessarily vary in shape, though nuances in the shape variables used were evident. A reduced major axis regression determined secondary osteon and Haversian canal isometry in the rib but positive allometry in the femur, suggesting different constraints in secondary osteon formation. This thesis concludes that bone histology, a product of remodelling, is in a complex relationship with age, sex, and social status (determining diet, health and access to resources) and that it changes depending on whether the femur or rib are investigated, and also on the rib sectioning location. It appears that rib and femur remodelling in modern Australia has remained similar to English medieval times. However, there is an allometric constraint on histology, which means that future rib and femur studies should account for bone size when examining histology. These results suggest that rib and femoral microstructure is influenced differently by different factors. This thesis is the first comprehensive study of bone histology applying multivariate and allometric analyses that includes modern Australian alongside medieval English samples.
Access status: Open Access ,
UX Design, Implementation and Evaluation for a Social Choice Board Game App
(2026) Zhu, Hongzhe
Computational social choice systems can support collective decisions, but their practical value depends on whether people can understand, influence, and accept the decision process. Group board-game allocation makes this problem concrete because participants need to coordinate preferences, player counts, teaching knowledge, familiarity, and possible multi-table assignments, while existing tools provide limited support for shared control and explanation. In this setting of collective decision-making, this thesis implements a human-centred framework for structuring information flow between participants and allocation algorithms. The framework is realised through PickNPlay, a participant-directed web system for collaborative game entry, tiered preference input, Z3-backed allocation, progress visibility, revision, and explanation, and extended through Boardot, an exploratory shared-station facilitation layer. Exploratory HCI sessions using observation, SUS questionnaires, interviews, follow-up material, and thematic analysis found that PickNPlay was rated as more usable over the formative Boardroom BGVS baseline, while Boardot showed comparable descriptive usability and made allocation more visible as a shared room-scale event. The findings suggest that solver-backed allocation becomes more acceptable when participants can see, shape, and revise the decision process. The thesis contributes a human-centred account of group board-game allocation as shared interaction infrastructure, showing how constrained collective decisions can be made more socially usable through transparency, recoverable coordination, and bounded facilitation.
Access status: Open Access ,
Expectations and Opportunities: Addressing the priorities and requirements of diverse Aboriginal and Torres Strait Islander peoples and communities in the Australian tertiary music education system
(2026) Newsome, Jennifer
The thesis describes a nationally focussed Indigenous-centred investigation of the priorities, requirements, and needs of diverse Aboriginal and Torres Strait Islander Peoples in engaging with the Australian tertiary music education system. The research responds to long standing historic inequities in which Australian First Nations music, musicians, and music making remain on the periphery of the work of Australian tertiary music institutions, and First Nations musicians continue to encounter systemic barriers to equitable access, participation, and success. The overarching aims of the research were to contribute to alleviating structural inequalities resulting from a legacy of settler-colonialism in the context of the Australian tertiary music education system by privileging the views and perspectives of Aboriginal and Torres Strait Islander people. The main goal of the research was to develop nationally focussed Indigenous-informed empirical evidence, grounded in the insights and perspectives of experientially informed First Nations stakeholders, as a means for enhancing the engagement of Australian tertiary music education institutions with diverse Aboriginal and Torres Strait Islander people, and improving outcomes of benefit for diverse First Nations Peoples and communities in the Australian tertiary music education system. The research comprised a first-time, bespoke, place-based, Indigenous-centred extended co-design case study conducted at the ANU School of Music at the Australian National University (ANU) from 2022-2025 and employed an Indigenous-centred participatory mixed-methods methodology embedded in an overarching framework of Indigenous-informed and Indigenous-centred co-design. The research design comprised four integrated components: The ANU School of Music Indigenous Reference Group, a series of four Indigenous Focus Group Co-design Workshops, a nationally focussed Survey Questionnaire, and three in-depth Interviews. The research findings provide comprehensive and detailed evidence-based insights into the priorities, requirements, and needs of diverse First Nations Peoples and communities in engaging with the Australian tertiary music education system, and ways in which tertiary music education institutions can address these, with specific reference to the ANU School of Music. For Australian tertiary music education institutions, the findings highlight the essential importance of inclusive and responsive policies, programs, and practices that recognise First Nations rights; align with First Nations cultures and values; support the identified learning priorities, aspirations, and needs of First Nations musicians; recognise First Nations diversity; and above all, observe Indigenous self-determination as the guiding principle. The study demonstrates the efficacy of Indigenous self-determination and Indigenous-centred co-design in developing evidence-based approaches to enhancing outcomes of benefit for diverse First Nations Peoples and communities in the Australian tertiary music education system. The research contributes data that adds to an understanding of the priorities, requirements, and needs of First Nations Peoples, and provides a set of recommendations for enhancing institutional responsiveness to the rights and interests of Australian First Nations Peoples and communities, and at the ANU School of Music specifically. The findings and recommendations are applicable also in other Australian tertiary music education contexts.
Access status: Open Access ,
Growth and characterisation of InAsP single quantum dots in InP nano/micro-cavities for single photon source applications
(2026) Huang, Xiaoying
Single-photon sources or emitters are at the core of quantum information technologies, ranging from quantum communication to quantum cryptography and quantum computing. Among various types of single-photon emitters, epitaxially grown semiconductor quantum dots have been recognised as highly promising candidates due to their superior optical performance, including high brightness, purity, and indistinguishability. The integration of single quantum dots into optical cavities to enhance the spontaneous emission rate is crucial for achieving high-quality single-photon emitters. While top-down fabrication approaches have been widely explored, deterministic positioning of single quantum dots remains a significant challenge. In this thesis, we develop a hybrid approach that combines droplet epitaxy with selective area epitaxy to deterministically position single quantum dots in various optical cavities, enabling both optically pumped and electrically injected single-photon source applications.
Access status: Open Access ,
Names, Descriptions And Existence Claims
(1983) Seto, Darryl
Designators are used only in language contexts. The sounds by Wittgenstein’s builders were not designators. There is one consequence of this for philosophy which I wish to point out. A study of any subject cannot be divorced from language and the situations in which the subject appears. Abstractions cannot be studied without looking at sentences where the concept is employed and the context which evokes this sentence. One rule that I would suggest consistent with this is in the philosophy of action. In any context there is a ‘right’ description of the action. Permissible descriptions follow rules in language governing how actions are to be described. A description must be responsive to the context which evokes this comment. Unless there is a story being told or a specific question asked, there is really no ‘right’ description.
Access status: Open Access ,
Effects of Neonicotinoid Insecticides on Soil Microbial Communities and Their Interactions with Selected Soil Properties
(2026) Akter, Sharmin
Neonicotinoids are globally dominant systemic insecticides, yet their effects on belowground microbial communities remain incompletely characterised. Soil microorganisms regulate nutrient cycling, organic matter decomposition, and agroecosystem resilience, making their responses to pesticide exposure central to understanding long-term soil health. This thesis investigated how neonicotinoid seed treatments shape soil bacterial and fungal communities across multiple timescales in Luvisol and Vertisol soils with contrasting textures. The research comprised a systematic review, a 10-day experiment with imidacloprid, thiamethoxam, and clothianidin, and a 28-day experiment examining imidacloprid effects across loamy sand, sandy loam, and clay soils. The review identified highly variable outcomes and major methodological gaps, including limited field studies, poor representation of fungi, and insufficient integration of soil physicochemical data. These gaps informed experiments integrating bacterial and fungal responses with soil properties. Microbial communities were characterised using 16S rRNA gene and ITS amplicon sequencing to assess diversity, taxonomic composition, co-occurrence networks, and predicted functional profiles. Short-term experiments showed selective bacterial compositional changes without a consistent overall diversity shift. Transient increases in bacterial diversity occurred under thiamethoxam and clothianidin, whereas imidacloprid reduced diversity by Day 10. Taxonomic responses were compound-specific, with Mesorhizobium consistently enriched across all neonicotinoids, while nitrifying and other bacterial taxa responded differentially among treatments. Fungal diversity remained largely stable despite temporally variable community composition. Clothianidin produced the greatest number of discriminatory fungal taxa, increased saprotrophs, and reduced symbiotrophs. The 28-day experiment demonstrated strong mediation by soil physicochemical context. Clay soil exhibited reduced evenness, less cohesive co-occurrence networks, and broad predicted functional suppression. Loamy sand showed intermediate responses, with increased network integration despite reduced diversity. Sandy loam maintained stable richness, evenness, and phylogenetic diversity and developed denser, more modular networks, indicating reorganisation rather than collapse. Functional profiles showed downregulation of carbohydrate and nucleotide metabolism pathways in fine-textured soils, suggesting constraints on carbon turnover and microbial energy flow under neonicotinoid stress. These contrasts may partly reflect inherent soil structure. The Vertisol clay, with shrink-swell behaviour and a more dynamic, compactible pore structure, may enhance variation in pore connectivity and chemical-microbe contact, whereas the more rigid Luvisol structures may moderate exposure and support greater microbial resilience. These differences likely contributed to contrasting community stability, network organisation, and stronger functional suppression in the fine-textured Vertisol. These findings were synthesised into a fate-effect-function conceptual model linking neonicotinoid persistence, microbial exposure, taxonomic restructuring, and functional consequences. The model provides a mechanistic framework for interpreting implications for biogeochemical cycling, biodegradation potential, and soil ecosystem services. Overall, this thesis demonstrates that neonicotinoid effects on soil microbial communities are dynamic, compound-specific, and mediated by soil texture. By linking microbial structural and functional shifts to agroecosystem processes, it advances the evidence base for neonicotinoid risk assessment and supports management strategies aimed at safeguarding soil health and agricultural sustainability.
Access status: Open Access ,
The Ageing Mind of the Double Brain: Studies in Hemispheric Asymmetry for Global-Local Processing
(2026) Chen, Haiwen
Global-local processing refers to a visual attentional mechanism that involves directing attention either globally (to an overall visual scene) or locally (to the finer elements within the scene). The two hemispheres of the brain demonstrate functional asymmetry for global-local processing, with global processing specialised in the right hemisphere and local processing specialised in the left hemisphere. Healthy ageing has been shown to influence global-local processing, with evidence suggesting that older adults demonstrate a local-processing bias. The right-hemisphere ageing hypothesis has been put forth to explain this bias, proposing that right-hemisphere functions are more vulnerable to ageing. In this thesis, hemispheric asymmetry for global-local processing was investigated using a hierarchical-figures task, in which a large stimulus was made up of several small stimuli. The hierarchical figures were presented briefly to the left or right visual field, such that information was initially processed by the contralateral hemisphere. Study 1 was an investigation of hemispheric asymmetry for global-local processing in neurologically healthy right-handed young (N = 27) and older (N = 34) adults. The question addressed was: Do stimulus categories with different demands on visuospatial-verbal processing (letters, verbalisable objects, and nonverbalisable shapes) influence hemispheric asymmetry for global-local processing in young and older adults? Study 2 was an investigation of the role of the right hemisphere in the non-directional component of attentional orienting in neurologically healthy right-handed young (N = 39) and older (N = 38) adults. The question addressed was: Do older adults demonstrate greater difficulties with disengaging attention from local-level information when correct responding required re-orienting attention to global-level information? Study 3 was an investigation of individual differences in hemispheric asymmetry for global-local processing in neurologically healthy right-handed young (N = 127) and older (N = 58) adults. The questions addressed were: Do individual young and older adults demonstrate right-hemisphere specialisation for global processing and left-hemisphere specialisation for local processing. If so, Do these individual differences in hemispheric asymmetry account for age-related changes in global-local processing? Study 4 was an investigation of age-group differences and individual differences in the perception of the Ebbinghaus illusion in neurologically healthy young (N = 87) and older (N = 58) adults. The question addressed was: Does a local-processing bias reduce susceptibility to the Ebbinghaus illusion? Four key conclusions emerged from this research. First, healthy ageing influences two aspects of global-local processing. Older adults demonstrate greater difficulties: (1) processing global-level information, and (2) disengaging attention from local-level information for the purpose of re-orienting attention to global-level information. Second, hemispheric asymmetry for global-local processing remains intact with age. In young and older adults, the right hemisphere (when compared to the left hemisphere), is more efficient for processing global-level information, and the left hemisphere (when compared to the right hemisphere) is more efficient for processing local-level information. Third, evidence for the right-hemisphere ageing hypothesis was mixed. Although older adults do demonstrate age-related difficulties in global processing, the right hemisphere of older participants was still more efficient compared to the left hemisphere at processing global information. Fourth, there are individual differences in the processing of global-level and local-level information. This thesis provides future research directions for understanding how healthy ageing influences functional hemispheric asymmetry, and the impact this has on visual attention across the life span.
Access status: Open Access ,
Generative Audio Synthesis in Sound, Speech, and Music
(2026) Niu, Xinlei
Audio is an important modality through which humans perceive and interpret the world. From speech and environmental sounds to music, it contains linguistic, emotional, and contextual information that can represent artistic expression. With the rapid progress of machine learning and generative AI, generative audio synthesis has emerged as a powerful approach to automatically producing realistic and diverse sounds, speech, and music content. However, current methods have challenges in requiring large computational resources, lacking flexibility across audio content, and offering limited controllability to users in practice. This thesis aims to tackle these limitations by developing audio synthesis techniques that are efficient, flexible, and controllable. This thesis explores how generative models can be designed to operate effectively under training resource constraints, adapt across different and diverse creative audio content, and allow for fine-grained and customized control to users. To achieve these goals, six complementary methods are proposed in this thesis. Among them, SoundLoCD in Chapter 3 and BDP in Chapter 5 focus on training efficiency, introducing a lightweight diffusion framework and a discrete latent optimal path modeling framework that preserve quality while reducing training computational requirements and strategies. HybridVC in Chapter 6 and SoundMorpher in Chapter 7 advance flexibility by enabling flexible voice conversion and seamless sound morphing across multi-modalities conditions. BVS in Chapter 4 and SteerMusic in Chapter 8 enhance synthesizing controllability, which allows fine-grained alignment between audio and visual context and empowers user-driven editing in music generation. In summary, these contributions form a unified perspective on AI-generated content of audio synthesis, which treats speech, sound, and music not as isolated problems but as interconnected domains of users immersive auditory experience. The resulting proposed methods move toward a future where audio generation is accessible, adaptive, and deeply integrated into creative, assistive, and interactive applications.
Access status: Open Access ,
On the Spatial Structure and Properties of Cold Neutral Hydrogen Gas In the Milky Way
Lynn, Callum
Despite its long period of study, there still remains no consensus on the dominant processes that control the rate of star formation. Neutral hydrogen (HI), being the most abundant element in the Universe, provides an important tracer, both for large scale galactic morphology and as the fundamental building block of stars. Improving our knowledge of the physical properties of HI and its transition between warm and cold phases is thus key to understanding the cycle of star formation and chemical enrichment in the Milky Way. Despite ongoing efforts, there still remains great uncertainty on the physical properties of cold and warm HI due to observational constraints of previous surveys. Presented here in this thesis are attempts to address questions surrounding the phase distribution and spatial structure of HI through detailed analysis of HI absorption and emission of the Milky Way from the Galactic Australian Square Kilometre Array Pathfinder HI Survey (GASKAP-HI). The first component of my thesis makes use of the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope, using the ~500 sightlines where HI 21cm absorption was detected in the Milky Way at high Galactic latitudes, and the ~2000 sightlines with no detections. The signal-to-noise is reduced through stacking sightlines to detect warmer gas in absorption. Gas was detected with a temperature of ~1300 K gas ubiquitous throughout the region, along with a lack of temperature variation spatially across the plane-of-sky. The work also provides a test for the efficacy of stacking HI spectra to detect higher temperature gas for future studies, finding that stacking, while producing lower limits on optical depth measurements, still allows for accurate measurements of temperature for components previously hidden under noise. Next, I have analysed the spatial variation of neutral hydrogen cold gas density across the plane-of-sky through computing structure functions of the detected GASKAP-HI absorption sightlines. The warm and cold gas follow different spatial power-law slopes (-2.6 vs -2.3 respectively), with both slopes being shallower than Kolmogorov turbulence (-3.6). The cold gas has a shallower slope due to more power existing on smaller spatial scales, where the cold gas is formed through condensation and shocks. I have also, for the first time, calculated the structure function of temperature of cold HI gas across the plane-of-sky. The structure function slope of the spin temperatures was flat, implying the temperature of cold gas is random across the plane-of-sky, not tied to any specific physical HI structures. Comparing with MHD simulations, the flatness of the structure function may indicate potential uncharacterised errors in the calculation of spin temperatures, and the need for a review of the currently accepted method for estimating temperatures for potential improvements. Finally, I present work focussed on characterising instabilities found in the HI emission data of a Galactic filament. Through Gaussian decomposition tools such as ROHSA, I was able to separate out spatially coherent maps of the individual neutral HI phases from emission data to study their interactions. The cold gas is concentrated within small scale structures undergoing Rayleigh-Taylor instabilities, with the warmer, more diffuse phases of HI gas enveloping the structure. Using the correlation between HI and dust to estimate physical distances to the structure, the wavelength of the Rayleigh-Taylor instabilities is estimated to be approximately 1 parsec in size. The work also investigates the effects of resolution on estimating cold gas mass fractions, since extra-galactic observations lack the spatial resolution of Milky Way surveys. Spatial resolution appears to have no effect on the mean and median cold neutral medium mass fraction, but the maximum value decreases with decreasing resolution.

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