Open Access Theses

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  • ItemOpen Access
    Sprinkle Magic on the Dance: Enriching a Verified Choreographic Language with a Simply Typed Lambda Calculus
    Lu, Xin
    Distributed systems are ubiquitous but writing endpoint programs can be error-prone since mismatched message sending and receiving can lead to errors such as deadlock, where the system indefinitely awaits a message. Choreography offers a solution by providing a global description of how messages are exchanged among endpoints, where message mismatches are disallowed — a property called “deadlock-free by design”. The global choreography is then projected into process models for each endpoint, preserving the deadlock-free property. While many choreography languages focus on message exchange behaviors, few address the local computations occurring within endpoints. Most current languages assume local computation results or delegate them to external languages. While this offers a reasoning ground for studying message exchange behaviours of choreography, when it comes to writing a concrete choreography program, the former can only exchange literal values and the latter leads to cumbersome code due to the addition of an external computation program which typically involves conversions between choreography values and external data types. Hence in this thesis, we extend Kalas, a state-of-the-art choreography language with verified end- to-end compilation, with a local language Sprinkles, such that local computations are handled gracefully within a few lines of codes. Moreover, it also allows us to formally analyse the message exchange behaviours of choreography when local computations are considered. Our proofs show that the strong normalisation property of Sprinkles implies progress for the enriched Kalas, and that the combination of type soundness and strong normalisation of of Sprinkles implies type preservation for non-recursive, synchronous transitions in the enriched Kalas.
  • ItemOpen Access
    The Origin of the Initial Mass Function: The Role of Gravity, Turbulence, Jets, and Radiative Feedback
    (2025) Mathew, Sajay
    Understanding the origin of stellar masses is one of the most compelling and important challenges in modern astrophysics. This is because the evolution and lifetime of a star, which are influenced by its mass, shape the structure and evolution of the interstellar medium of galaxies. Understanding the origin of the mass of a star is directly linked to understanding the mass distribution of stars since stars generally form in clusters. The stellar mass distribution is referred to as the initial mass function (IMF). The IMF is often thought to be relatively universal, and explaining the IMF characteristics like the existence of a peak mass and the power-law nature at the high mass end lies at the forefront of star formation research. In this thesis, I perform a comprehensive parameter study of the IMF using state-of-the-art star cluster formation simulations that incorporate physically important mechanisms such as gravity, turbulence, magnetic fields, jets, and radiative heating. I show that the inclusion of outflow feedback in numerical simulations is essential to accurately model star formation and the IMF, as its effects significantly influence other key physical mechanisms such as turbulence and stellar radiative heating. I find that protostellar outflows shift the IMF to lower masses by roughly a factor of 2. Furthermore, I find that variations in the mode of turbulence driving play a significant role in shaping the form of the IMF, where a purely compressive (curl-free) turbulence driving produces a higher fraction of low-mass stars as compared to a purely solenoidal (divergence-free) driving. Changing the turbulence driving mode in simulations from purely solenoidal to purely compressive decreases the median stellar mass by a factor of 1.5. My study suggests that the dominance of solenoidal turbulence driving modes and relatively high cloud virial parameter values detected in the vicinity of the Galactic centre can partly explain the top-heavy nature of the IMFs in the associated clouds I propose that the scatter in the IMF observed in different regions of the Milky Way is due to the difference in the environmental conditions. I also use the results from my simulation suite to study the binary properties of stars, which are closely tied to understanding the IMF. I verify that my simulations reproduce the observed trends like the increasing multiplicity fraction with mass and the dependence of orbital eccentricity on binary separation. I find that the turbulence driving mode has a considerable influence on the binary eccentricity, with simulations having compressively driven turbulence producing a higher fraction of high-eccentricity binaries as compared to simulations with solenoidal or a mixture of driving modes. This implies that the universal eccentricity distribution often used as an initial condition in N-body simulations of stellar cluster dynamics needs revision and further shows the broad impact of my work. I conclude that the IMF and the binary properties are controlled by the combined effect of gravity, magnetic fields, turbulence and protostellar feedback. The inferences from my studies can be used to calibrate sub-grid models in large-scale simulations of galaxy evolution, which often assume a universal IMF independent of the local physical conditions. This would enable more accurate modelling of energy output from star clusters, which are crucial drivers of galaxy evolution. My study advocates for future observational surveys to quantify the associated cloud conditions, such as the turbulence properties, together with measuring the IMF of star clusters. Creating distinct ensembles of observational IMFs for various cloud conditions would enable isolating the individual effects of different physical mechanisms and facilitate one-to-one comparisons with my theoretical work. Meticulous comparisons between observations and theory are quintessential to deepening our understanding of the IMF and star formation.
  • ItemOpen Access
    Religious Regulations And Persecutions In Contemporary Indonesia: A Case Study Of The Ahmadiyah Community
    (2025) Cerdikwan, Cerdikwan
    Most research on minority rights and religious conflict emphasises national inter-religious tensions. This study shifts the focus to intra-religious conflict at the local level, examining why Ahmadiyah followers, a Muslim minority in Indonesia, face persecution. Despite 568 recorded cases across 56 districts and cities, not all regions with restrictive religious regulations experience significant persecution, suggesting that other factors are at play. This study employs a comparative case study design, focusing on Depok, Bogor, and Bandung City, and draws on 70 in-depth interviews with stakeholders including mayoral candidates, religious leaders, Ahmadiyah followers, Islamic vigilante group leaders, and Muslim civil society organisations. The findings reveal a strong link between local political dynamics, particularly during mayoral elections, and the persecution of Ahmadiyah followers. Nearly 80% of these incidents occurred around elections, as candidates exploited Ahmadiyah issues to appeal to conservative Muslim voters. Three primary factors contribute to this persecution: (1) intense political competition, (2) the influence of conservative religious leaders, and (3) the weak impact of Muslim civil society organisations advocating for religious pluralism. This means that the persecution of the Ahmadiyah community is driven by local political dynamics, particularly during mayoral elections and intense political competition. Persecution escalates when there is fierce political rivalry, as candidates exploit the Ahmadiyah issue to enhance their Islamic credentials, gain votes from conservative Muslims, and secure support from Islamic hardliners and conservative local religious leaders. Additionally, the weak influence of Muslim civil society organisations supporting religious pluralism contributes to this persecution. This research underscores how electoral strategies at the local level can intensify religious persecution, offering insights into how such conflicts might be mitigated.
  • ItemOpen Access
    Ready Player Won: A study of e-sports' compatibility with South Korean nation-branding and development of national star power
    (2025) Grantham, Amy
    Over the last decade viewership trends for e-sports (competitive videogaming) have been outstripping once-sacred physical sports events like the Superbowl. E-sports management companies' valuations have soared to hundreds of millions of US dollars, while tournaments and athletes have been sponsored by some of the most prestigious luxury brands on the market. E-sports has even become a medalled event in the quadrennial Asian Games, and continues to be actively considered for inclusion in the biggest multinational competitive event in the world: the Summer Olympics. Yet it continues to be conspicuously absent from formal nation-branding contexts in lieu of music, film, and physical sports, even by famed e-sports pioneers like South Korea. This dissertation takes e-sports as a primary case study to assess ways that different entertainment industries can be used in nation-branding, and the functional utility that they have in different foreign and domestic policy contexts. It asks which specific aspects of e-sports help or hinder its use in nation-branding campaigns, particularly through the lens of national "star power": a concept describing the image-based charm and "likeability" of a country, such that target audiences become predisposed to liking and supporting the wielding country itself rather than simply acceding to its forceful or transactionally persuasive demands in a discrete situation. Employing a multidisciplinary method, the dissertation specifically examines entertainment industry-oriented influence campaigns from the perspective of South Korea. These are juxtaposed with shortform studies of the United States to further map the applications of e-sports in (inter)national fora. The dissertation finds that e-sports functions as a powerful catalyst for individual and industrial star power, including by dint of its global audience diversity, promotional viability across platforms, athletes' personal renown, and transcendence of linguistic and geographic divides. These have been successfully leveraged to overcome operational challenges to e-sports' deployment by governments, including intellectual property rights, multinational compositions of professional teams, and limited visibility of governments' in-person e-sports promotions to foreign audiences in South Korea. E-sports' near-invisibility in South Korea's leader-level nation-branding campaigns is found to be a matter of government convenience (prioritising industries that achieve a "mainstream moment" in target countries' media landscapes), rather than any fundamental incompatibility between e-sports and nation-branding. This research provides significant contributions in three areas. It addresses major gaps in academic-practitioner conceptual frameworks of influence in international relations, particularly with respect to national "attractiveness", national "personalities", and curation of mimetic desire. From a cultural studies perspective, it also serves as one of the first comprehensive academic investigations into the global e-sports industry, providing insights into its internal operations and external applications from the perspectives of three major stakeholder groups: governments, athletes, and fans. Finally, it maps these findings in relation to K-pop, K-cinema, and physical sports, deepening understandings of entertainment industries' idiosyncrasies and their ability to generate substantial international star power.
  • ItemOpen Access
    Genomic Epidemiology for supporting Public Health in Australia
    (2025) Peacock, Patrick
    This dissertation presents the work undertaken and results for the series of projects completed during my field placement to satisfy the requirements of the Master of Philosophy (Applied Epidemiology). My placement was facilitated at the Centre for Infectious Diseases and Microbiology - Public Health within the Institute for Clinical Pathology and Medical Research - NSW Health Pathology, Westmead Hospital, NSW. I worked alongside multiple reference laboratories including the Microbial Genomics Reference Laboratory, the Enteric Reference Laboratory, and the Antimicrobial Resistance Reference Laboratory in addition to collaborating with colleagues within the NSW Ministry of Health, Public Health Units and ACT Health. Genomics has become a powerful tool for the investigation of pathogens of public health interest. In late 2022 an aged-care facility in the ACT experienced an outbreak of COVID-19. Subsequent investigation identified multiple cases with a heavily mutated virus, indicative of molnupiravir-induced mutations. The antiviral medication, molnupiravir, saw widespread prescription rates in Australia, particularly in the aged care sector. While there have been suggestions in literature that molnupiravir treatment may not always result in non-viable virus, there had not been any epidemiological linked information confirming this to date. Treatment of Shigellosis cases are often complicated by antimicrobial resistance (AMR). Phenotypic AMR testing on Shigella spp. is not routinely performed by diagnostic laboratories nor is there a standardised panel of antimicrobials to test against. The NSW Ministry of Health requested a study to evaluate the feasibility of incorporating genotypic AMR prediction into the Shigellosis surveillance system. I performed analysis of the quality of current AMR data and compared the genotypic and phenotypic results for samples from 2022. A high degree of concordance was found and where inconsistencies were found, we requested the Antimicrobial Resistance Reference Laboratory to perform repeat phenotypic testing. The repeated results were concordant with our genotypic predictions giving further confidence in accuracy of genotypic predictions. It was recommended to incorporate reporting of genomic results as a part of longer trend analysis to inform empirical treatment while performing periodic phenotypic testing on samples to ensure genotypic predictions remain accurate and comprehensive. NSW has been prospectively sequencing all referred isolates of Salmonella enterica serovar Enteritidis and Salmonella enterica serovar Typhimurium since 2016. These serovars are responsible for most foodborne illness in NSW and while not common, can have severe disease presentations. I confirmed the hypothesis that S. Enteritidis is approximately twice more associated with severe disease than S. Typhimurium. I performed a further data analysis on the Salmonella dataset examining the proportions of AMR and multidrug resistance (MDR). This identified that whilst S. Enteritidis had a slightly higher proportion of any amount of AMR, S. Typhimurium had a higher proportion of MDR isolates. However, this higher proportion of MDR was biased by a subset of S. Typhimurium, multi-locus sequence type 34, having a very high (over 80%) proportion of multidrug resistance.
  • ItemOpen Access
    Reading Riverside: History and Heritage in Canberra's Oldest Public Cemetery
    Adams, Timothy
    The processes of death and mortuary practices in colonial Australia are often mythologised to fit the romantic notion of the early Aussie battler. However, practices of mourning, eulogising and memorialising the dead in Anglo-Australian society has always been complex and colourful, reflecting the mixing of common English traditions with vernacular Australian practices. Due to the tyranny of distance, these practices, while rich and complex, often varied from place to place, reflecting local fashions and community practices. As a result, cemeteries provide a remarkable archive of social and cultural history for local communities. This thesis uses Queanbeyan’s Riverside Cemetery as a case study, illustrating the social and cultural development of the Canberra region between the mid 19th -20 th centuries. Analysis of the cemetery illustrates political, racial and ideological changes over a period of 150 years. The thesis also demonstrates the ambiguity of heritage value and investigates the many influences on the heritage conservation process, as well as the inherent difficulties in this process. The balance between the importance of conserving a community’s past, and the requirements of planning for a modern and growing community, is shown to be a difficult one for a small Council, one that cannot be achieved without deep community involvement.
  • ItemOpen Access
    Chasing 'Wonders': Textures and Infrastructures of Circular Economies in Cambodia
    (2025) Lau, Justin
    Imagine a world in which sewage can become drinking water, food scraps can end up back on your dinner table as a nutritious meal, waste never ends up in landfill, resources are never exhausted. Such a wondrous world is not far from the future. The circular economy model is designed to realize this vision by eliminating waste, promoting material reuse, and regenerating nature. Chasing 'Wonder' seeks to reimagine the circular economy by exploring what makes this model appealing and what is at stake when such a wondrous world fails to materialize. It argues that circular economies are multiple fantastical projects that are continually being made and remade. Based on year-long multi-sited ethnographic research in Cambodia, this study traces different emerging forms of circular economies, from a black soldier fly farm to a wastewater treatment project. In the absence of reliable waste infrastructure in Cambodia, the circular economy model is increasingly promoted by the government as an alternative waste management solution. In examining how different grassroot initiatives design waste infrastructures to enact circular economies, this study reveals the lives that are inadvertently embroiled in such circular endeavours. Much of the anthropological literature has critically challenged the circular economy model for operating as growth-driven capitalism writ large. What remains under-examined and conceptualized is how certain imaginaries of circular economies take hold and become diverging more-than-human sites of constraints, predicaments, and/or possibilities for different waste actors. Chasing 'Wonder' provides an alternative ethnographic account by charting out these divergences and the varying allures and effects of the ever-transforming circular economies. It offers an innovative contribution by bringing the anthropology of waste into conversation with science and technology studies, feminist new materialisms, and disability studies. Such an approach enables us to re-examine the seemingly wondrous circular economies by foregrounding their textures, inconsistencies, and multi-edged ramifications.
  • ItemUnknown
    Three Essays in Corporate Finance
    (2025) Viriyavejkul, Arnan
    The first chapter explores the causes and consequences of incorporating inventor directors into corporate boards. Our investigation reveals that firms opting for inventor director appointments are characterised by complexity and a pronounced demand for advisory input. At the firm level, our results show that firms with at least one inventor director on their board experience an increase in innovative output, as measured by patent counts, citations, and the economic value derived from these patents. The causal relationships between inventor director presence and innovation output are established through director turnover analyses, focusing on events of director departure and retirement. Our findings remain robust across a variety of additional controls, model specifications, and definitions of variables. Notably, the impact of inventor directors is more significant in firms with high advisory and monitoring needs. Furthermore, there are additive synergies when both CEOs and directors are inventors. Collectively, our research offers compelling evidence of the important role of inventor directors in enhancing board effectiveness, particularly in fostering an innovative landscape. The second chapter investigates the relationships between inventor CEOs and earnings management, revealing that inventor CEOs are negatively associated with real earnings management, prioritising long-term value creation and financial transparency. Firms with inventor CEOs demonstrate higher earnings quality and transparency. Utilising a CEO turnover approach, we find that CEO turnover involving inventor CEOs increases both real-activity and total earnings management. This suggests that inventor CEOs' focus on sustainable growth and innovation diminishes the need for earnings manipulation, providing crucial insights for investors, analysts, and regulators. Additionally, high-productivity and active inventor CEOs are especially effective in reducing real-activity earnings management, with the negative correlation being more pronounced in firms with high analyst coverage and low board monitoring. This highlights the role of external and internal governance in shaping earnings management practices. Furthermore, we show that inventor CEOs, due to their long-term incentives, attract dedicated institutional investors and deter transient institutional investors. Finally, we find that inventor CEOs, due to their focus on long-term innovation projects, are negatively associated with earnings surprises, and that the effects of these earnings surprises on cumulative abnormal returns are more pronounced in firms led by inventor CEOs, as markets react more strongly to the inherent uncertainty and long-term nature of their innovative activities. The third chapter studies the impact of R&D tax credits on the presence of inventor directors on corporate boards. We find that R&D tax credits are associated with a higher likelihood of having an inventor director on corporate boards. The effect is more pronounced in firms operating within high-tech industries, those with substantial R&D expenditures, and larger size. We show that the positive relationship is causal and robust based on a battery of empirical tests, including staggered difference-in-differences (DID) designs to explore the dynamic effects of R&D tax credits. Further analysis indicates that inventor directors, influenced by R&D tax credits, typically serve as internal directors, particularly within the C-suite, and enhance firms' innovation outputs. Furthermore, our research has documented that R&D tax credits are associated with increased director compensation, serving as a significant incentive mechanism. Overall, our findings bridge fiscal policy and corporate governance.
  • ItemOpen Access
    Peptide Drug Conjugates: An Exploration for Antimalarial and Anticancer Treatments
    (2025) Palombi, Isabella
    Small molecule drugs are essential in the treatment and management of acute and chronic diseases. However, they often possess disadvantages such as nonspecific interactions with healthy cells and can suffer from loss of efficacy as pathogens or diseased cells gain drug resistance. The approval of antibody-drug conjugates (ADCs) for cancer treatment has highlighted targeted drug delivery as a novel therapeutic approach to overcome some of the limitations of small molecules. Inspired by the success of ADCs, peptide-drug conjugates (PDCs) provide an attractive and cheaper alternative for the exploration of targeted drug delivery. In this thesis, three small molecule drugs, primaquine (PQ), camptothecin (CPT) and vemurafenib (Vem), are conjugated onto bioactive cell-penetrating peptides to understand if certain drug liabilities, such as off-target toxicity or drug resistance, can be mitigated through peptide conjugation. The exploration of PDCs in both an infectious disease context (malaria) and a noncommunicable disease context (cancer) will highlight these emerging therapeutic modalities as a versatile tool for targeted treatments. Chapter One introduces PDCs as a promising tool for targeted therapy and highlights the need for such an approach in the treatment of both infectious and noncommunicable diseases. The different design aspects of PDCs are discussed, including the types of targeting peptides, different linker technologies and alternative conjugation strategies. The design, synthesis and biological evaluation of a suite of PDCs in different disease contexts will be underlined as the key theme explored in this thesis, which is subdivided into chapters based on the identity of the PDC drug cargo. Chapter Two discusses the synthesis of six PQ-containing antimalarial PDCs, each with varied design characteristics, and the subsequent biological evaluation of their killing ability against Plasmodium parasites. The insights provided by changes in the low micromolar activity for different PDC analogues revealed that conjugation site and linker type play an important role in PDC potency. These first-generation conjugates highlighted PDCs as a feasible approach to antimalarial therapy, an area that remains underexplored for this treatment type. Chapter Three investigates the synthesis of four anticancer PDCs containing CPT, a small molecule drug with off-target toxicity. The knowledge of the relationship between design characteristics and potency from the previous chapter was used to inform PDC construction. Biological evaluation of the PDCs against a melanoma cancer cell line revealed nanomolar to low micromolar potency, albeit with toxicity against a noncancerous cell line. The non-selective nature of the PDCs reinforced the importance of design in PDC development, including matching drug cargo with the correct carrier molecule. Chapter Four explores the synthesis of five Vem-containing anticancer PDCs and details their killing ability against melanoma cell lines that are sensitive and resistant to the drug cargo. The resulting PDCs had selective low micromolar activity against the drug-sensitive cell line. Evaluation of peptide-linker controls containing no drug highlighted the contribution of each PDC component to PDC activity and indicated the importance of the peptide carrier to overall potency. One of the PDCs was also active against the drug-resistant cell line, emphasising this approach as a feasible means to reinvigorate interest in small molecule drugs with resistance issues. Chapter Five summarises the above projects on antimalarial and anticancer PDCs utilising bioactive cell-penetrating peptides. A perspective is provided on the prospects of future generations of PDCs and how the lessons learned throughout this thesis will inform design considerations.
  • ItemOpen Access
    Applied Epidemiology in North Coast NSW
    (2025) Ellis, Megan
    I undertook my Master of Philosophy in Applied Epidemiology (MAE) placement at North Coast Population and Public Health (NSW Health) in Coffs Harbour from March 2023 to October 2024. This thesis presents the activities and projects I was involved in during my placement. The first chapter provides an overview of my field placement and the activities I was involved in outside of my major MAE projects. The second chapter presents an epidemiological study examining syphilis testing trends for people who use drugs attending sexual health services in North Coast NSW between 2022 and 2023. Chapter three reports an investigation of a gastrointestinal illness outbreak in attendees to a Tweed Heads birthday dinner. The fourth chapter involves a data analysis of Q fever notifications in North Coast NSW between 2014 and 2023. The fifth chapter presents the evaluation of the residential aged care facilities acute respiratory infection outbreak surveillance system in North Coast NSW. Finally, chapter six details my teaching experience during the lessons from the field and teaching first year MAE students' sessions. The work presented in this thesis demonstrates my ability to meet the core competencies required for the MAE program and contribute to public health research and practice.
  • ItemOpen Access
    Investigating the Similarities and Differences Between Orthorexia Nervosa and Eating Disorders Using Implicit and Explicit Measures
    (2025) Clifford, Rosemary
    The term Orthorexia Nervosa (ON) emerged in the 1990s to describe a condition characterised by an obsessive preoccupation with healthy/pure eating that leads to physical and psychological impairment. Since its inception, there have been several debates regarding ON, including questions about where it is best categorised in diagnostic manuals, whether it represents a new eating disorder (ED) or a subtype of a currently recognised ED, and whether body image concerns are a feature. The current research aimed to inform such debates through three studies comparing participants with elevated ON symptoms and ED symptoms (ED/ON), participants with elevated ED symptoms (ED), and healthy comparison (HC) participants (i.e., an absence of ON or ED symptoms and no history of shape/weight concerns). Study 1 investigated the presence of ED symptomatology, body image concerns (appearance focus and appearance satisfaction), psychological distress, ED-specific impairment, and general mental and physical health in those with elevated ON symptoms compared to those without. Results indicated that higher levels of ED symptomatology, appearance focus, and ED-specific impairment were found among those in the ED/ON group relative to the ED and HC groups. The ED/ON group was comparable to the ED group, but higher than the HC group, in terms of appearance satisfaction, psychological distress, and general mental and physical health. Study 2 investigated the implicit associations to food and body stimuli of those with ON compared to those without. This study compared the implicit associations of the same three groups of participants as Study 1 utilising three Implicit Association Tests (IAT) assessing attitudes towards health- versus appearance-based stimuli. These included two picture-based IATs (one assessing attitudes towards healthy/average-weight female bodies versus thin/unhealthy female bodies, and one assessing attitudes towards healthy/high-calorie foods versus low-calorie/unhealthy foods) and one questionnaire-based IAT (assessing attitudes towards health- versus appearance-focused statements). Results indicated that participants across all groups exhibited a more favourable view towards the health-based stimuli than the appearance-based stimuli, with the ED/ON participants exhibiting the least favourable view towards the health-based stimuli among the three groups, and the ED and HC participants exhibiting comparable attitudes. Finally, Study 3 investigated the cognitive processing of those with ON compared to those without by focusing on attentional bias towards food and body stimuli. Utilising the same participant sample and stimuli image sets as Study 2, attentional biases towards healthy/average-weight bodies, thin/unhealthy bodies, healthy/high-calorie food, and low-calorie/unhealthy food images were assessed using a series of Visual Probe Detection Tasks (VPDTs). Results indicated that the ED/ON group demonstrated greater attentional bias towards thin/unhealthy bodies, healthy/high-calorie, and unhealthy/low-calorie food compared to the ED and HC groups, but not for healthy/average-weight bodies. Overall, the current research indicated that ON symptoms in the context of an ED were associated with a greater focus on appearance and more elevated levels of ED-specific impairment, a less favourable view of health-based stimuli, and a greater attentional bias to food and body stimuli. If replicated, the findings suggest that the additional presence of ON symptoms in those with an ED signifies a more severe presentation, which has both diagnostic and treatment implications.
  • ItemOpen Access
    Perovskite Solar Cells for Space Applications
    (2025) Nguyen, Thuan
    Perovskite solar cells (PSC) technology has seen significant advancements since its initial introduction in 2009. There is a growing interest in utilizing PSC technology for space application. However, the stability of PSCs in space environments remains unclear. This thesis aims to investigate the degradation mechanism of perovskite in space conditions and improve the performance and stability of PSCs to meet the requirements for space missions. PSC technology offers a promissing power option for space applications due to its high power-to-weight ratio and tolerance to space radiation. A new simulation-based method has been developed to predict the degradation of PSCs under proton radiation. This method uses ion scattering simulations to generate depth-dependent defect profiles based on proton energy and fluence, which are then used in optoelectronic simulations to predict degradation. The study compares the radiation tolerance of inorganic perovskite CsPbI2Br and organic-inorganic perovskite FAMAPbI3, and predicts that CsPbI2Br and FAMAPbI3 cells retain 62% and 65% of their initial efficiencies after 100 keV proton radiation with a dose of 1e14 p.cm-2, respectively. It also shows that radiation direction must be considered when predicting rdiation tolerance, as the spatial overlap between photogenerated carriers and radiation-induced defects significantly impacts the cell performance. This method is used to predict mission end-of-life performance of PSCs, taking into account the full proton radiation energy spectrum and fluence and the incident direction. Additionally, the study assesses the impact of 10 MeV proton radiation on perovskite films and PSCs at fluences in range from 1e12 to 1e14 p.cm-2, which is equivalent to 1 to 100 years in Geosynchronous equatorial orbit (GEO) without any shielding or cover. For the first time, void formation and material ablation were detected, showing the degradation mechanism due to structural damage. As a result, these led to the degradation of PSCs to 89% of the initial performance at the highest dose. Finally, the study disscusses the device performance and stability improvements via management of excess lead iodide (PbI2) in PSCs. This method, known as buried interface modification, effectively adjusts the amount of excess PbI2 in PSCs at both the bottom surface and the bulk of the perovkite layer, achieving high efficiencies with negligible hysteresis and excellent stability via defect passivation. The approach is effective for both negative-intrinsic-possitive (n-i-n) and possitive-intrinsic-negative (p-i-n) structures.
  • ItemOpen Access
    Rare earth element mineralisation in Australia
    (2025) Chandler, Ross
    Australia hosts a variety of Rare Earth Element (REE) deposits. Whilst carbonatite-associated deposits are the only style currently mined, some peralkaline volcanic and Iron Oxide Copper Gold (IOCG) systems also contain economic concentrations of REE. Despite growing interest in REE, the ore genesis of all three deposit styles in Australia remains understudied, hampering effective utilisation of the nation's Critical Metal resources. This thesis addresses this knowledge gap first by assessing known occurrences, followed by microanalytical and geochemical studies of REE mineralisation nationwide. Firstly this thesis presents a compilation of the geological and isotopic characteristics of Australia's carbonatites. The 16 known carbonatites range from Neoarchean to Jurassic in age, are all hosted within Proterozoic (or older) crust and are extremely geologically diverse. They range from multiphase intrusive complexes dominated by carbonatite (e.g. Gifford Creek and Mt Weld, WA) or silicate rocks (e.g. Cummins Range and Cundeelee, WA), to small volume carbonatite dykes (e.g. Yungal dykes, WA). The diversity is reflected in radiogenic isotopic signatures (Rb/Sr and Sm/Nd), which indicate derivation from a variety of mantle sources. REE and Nb mineralisation is hosted within both primary carbonatite and overlying carbonatite-derived regolith, with dolomite carbonatite displaying greater increases in REE grade during weathering, compared to siderite carbonatites. The second part of this thesis focusses on the Mt Weld carbonatite (WA), which hosts a large REE deposit within the regolith overlying a c. 2.06 Ga carbonatite complex. Samples are taken from an exploration drill hole, and reveal an intrusive architecture of inner REE-mineralised magnesio- to ferrocarbonatite (c. 600m diameter) surrounded by an annulus of REE-poor calciocarbonatite (c. 1.2km thick). Monazite is the main host of REE, with textures and chemistries suggestive of a period of late hydrothermal mineralisation. A comparison of carbonatite and regolith geochemistry suggests minimal horizontal migration of ore elements during regolith formation, displaying a ~5x upgrade in REE during weathering. Thirdly, REE mineralisation within the Bingie Grumble peralkaline trachyte (NSW) is investigated. REE are hosted within magmatic eudialyte that is variably pseudomorphically replaced by intergrown amorphous zircon, hydroxylbastnasite-(Nd) and an array of Ce silicate (Mn) phases. 40Ar/39Ar geochronology confirms a c. 17.1 Ma age for the trachyte. Using mineral and whole-rock chemistries, a model for the deuteric (autometasomatic) alteration of the trachyte is presented, where hydrothermal fluids from the de-volatilisation of the erupting lava interact with eudialyte, causing pseudomorphic replacement by secondary mineral assemblages. The deuteric fluids efficiently oxidised CeIII to CeIV and in some cases, transported trivalent LREE significant distances within flows, forming Ce-deficient hydroxylbastnasite-(Nd), some of the most Nd-rich naturally occurring minerals reported to date (up to 34% Nd2O3). Finally, this thesis presents a study on the Cu-Au-U systems of the eastern Mt Isa Inlier (QLD) which identifies two distinct styles of REE-enriched deposits: F-Ba rich IOCG deposits and U-Cu-Au skarn deposits. The first is characterised by a single phase of REE and Cu mineralisation, and the latter by early REE and U-rich skarn formation followed by a late Cu-Au overprint. REE patterns systematically vary between deposit types, with IOCG deposits characterised by positive Eu anomalies in mineral and whole rock, while skarns have negative Eu anomalies. These observations suggest distinctly different mechanisms of ore formation. The contrasting behaviour of Eu between the two deposit types may reflect the metal source in each deposit type, supported by an association of the skarns with evolved intrusives, and the F-Ba rich IOCGs with regions of albitisation.
  • ItemOpen Access
    Developing Novel Methods for High-Field Electron Paramagnetic Resonance Measurements of Biomolecules
    (2025) Judd, Martyna
    The scope of Electron Paramagnetic Resonance (EPR) spectroscopy has expanded dramatically in recent decades as a powerful tool for biomolecular structure determination. Advancements in high-frequency microwave instrumentation have motivated the exploration of novel measurement methods, probehead design, and biomolecular spin technologies, which take advantage of the increased sensitivity and resolution that comes with detecting unpaired electrons at high magnetic fields. High-field EPR provides a promising avenue for visualising molecular events in biological cells and addressing key challenges of modern drug discovery. This thesis aims to contribute to ongoing high-field EPR developments and their application to structural biology. The thesis is divided into two parts. Part I focuses on the Electron-Nuclear Double Resonance (ENDOR) experiment at 94 GHz to measure 5-30 A distances between an electron and nuclear spin. This range is notoriously difficult to capture using standard techniques, but can be accessed by ENDOR through exploiting the spectroscopic advantages of 19F and the S = 7/2 paramagnetic Gd3+ ion at 94 GHz. Chapter 3 shows that 19F ENDOR can resolve distances and conformational dynamics in proteins tagged with Gd3+ and 19F spin labels for dipolar interactions up to 16 A. The 19F ENDOR detection limit is pushed to >20 A by using the distance dependence of the ENDOR intensity, overcoming the chase for linewidth resolution. Systematic 19F ENDOR measurements of molecular rulers with well-defined 19F-Gd3+ distances validate the integrated-intensity approach to reliably access distances up to 30 A in spin-labelled protein. This approach is thoroughly benchmarked by lineshape modelling and statistical error analysis. Lastly, by using a novel, complementary set of luorinated aromatic amino acids, the orientation of buried side chains can be accurately constrained in metalloproteins with rigid Gd3+ sites. In proteins labelled with flexible Gd3+ tags, 19F ENDOR lineshape analysis combined with rotamer simulations provides information on the conformational distribution of trifluoromethyl-labelled side chains. In Chapter 4 this approach is expanded to other magnetically active nuclei. 31P Mims ENDOR is used in tandem with EXAFS measurements to validate the binding mode of luminescent lanthanide complexes to different polyphosphates, to understand and optimize these complexes in biological sensing and cell imaging applications. ENDOR provides important insight into binding mode heterogeneity which cannot be easily obtained by other techniques. Part 2 pivots to the development of new resonators for EPR measurements at Q-band (34 GHz) which bridge the requirements of high-sensitivity, narrowband detection for CW EPR, with the need for efficient off-resonance excitation in a broadband resonator for pulse EPR experiments. In Chapter 6 the standard 34 GHz TE011 cavity is modified with a dielectric plate covering the coupling iris to increase the resonator bandwidth while retaining sensitivity. Experiments demonstrate the dependence of the resonator bandwidth on the dielectric thickness, coupling short position, and cavity dimensions and show good agreement with finite elements electromagnetic calculations. This modification was implemented into a movable dielectric coupling short, to easily interchange between the original critically coupled CW mode and the dielectrically overcoupled mode. Finally a new 34 GHz TE01d3 dielectric probe is presented, which outperforms both the TE011 cavity and Bruker EN 5107D2 dielectric resonator sensitivities, and overcomes limitations of standard dielectric resonators, i.e. lack of frequency tunability and sample-size restrictions. The TE01d3 resonator is also compatible with the dielectric coupling mechanism. These developments are well-positioned to allow EPR experiments with different resonator requirements, to be measured in a unified, general-purpose set up.
  • ItemOpen Access
    Physiology and Plasticity of Sensory Synapses in the Piriform Cortex
    (2025) Palmer, Daniel
    In this thesis, I utilise in vitro slice models to investigate the structure, physiology and plasticity of synapses delivering sensory (afferent) information from the olfactory bulb (OB) to the primary excitatory neurons of the PCx, semilunar (SL) and superficial pyramidal (SP) cells. Given the relationship between postsynaptic morphology and synaptic transmission, I first used enhanced-resolution confocal microscopy to investigate the dendritic structure and distribution of spines on the apical arbours of the two target cell types. SP cells displayed more complex dendritic trees and a higher spine density than SL cells. Interestingly, although arranged at a lower density, spines on the distal apical dendrites of SL cells (where afferent input is received) were significantly larger than those on SP cells. As a result, synaptic opportunity (defined as total spine head surface area per unit dendritic length) was similar for both cell types. In view of the substantial differences in spine structure and distribution, I next combined minimal electrical stimulation with whole-cell somatic recordings to investigate the properties of afferent synaptic transmission. These experiments showed that SL cells receive significantly larger unitary synaptic inputs from the OB than do SP cells. Variance-mean analysis and strontium-evoked asynchronous EPSCs revealed that these powerful inputs to SL cells are driven by both a higher neurotransmitter release probability (Pr) and higher quantal amplitude (Q). As a result, SL cells can be lifted to action potential threshold with fewer afferent inputs than SP cells. Next, I asked whether the disparity in afferent synaptic structure and transmission to SL and SP cells extended to their ability to express synaptic plasticity. Using patterned extracellular stimulation, N-methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP) and depression (LTD) could be observed using field recordings. When isolating unitary inputs, however, LTP and LTD could only be induced at afferent-SL synapses, with no reliable plasticity inducible at afferent-SP inputs. Interestingly, afferent-SL LTD was expressed both pre- and postsynaptically, with variable changes in Pr (presynaptic) and Q (postsynaptic) observed. On the other hand, afferent-SL LTP was predominantly presynaptic and appeared to depend on the prior Pr of the stimulated input, such that low Pr synapses could be potentiated while high Pr synapses could not. In a final set of exploratory experiments, I investigated the excitability of SL and SP cell dendrites. Dendritic NMDA spikes can evoke synaptic potentiation at afferent inputs, so it was important to understand whether the plasticity I observed depended on this mechanism. I made whole-cell recordings from both somas and dendrites of SL and SP cells while systematically increasing the strength of afferent extracellular stimulation. Although putative dendritic electrogenesis was observed at high stimulation strengths, synaptic responses scaled linearly through the minimal stimulation range, indicating that the unitary stimulation strengths used in my plasticity experiments did not evoke active dendritic events. Overall, the experiments presented in this thesis reveal distinct differences in how SL and SP cells receive and process monosynaptic sensory information from the OB. From dendritic spine structure through to synaptic transmission and plasticity, SL and SP cells are markedly distinct. Given that these cells are the dominant glutamatergic cell types of the PCx, and receive the majority of monosynaptic afferent input from the OB, understanding how they process olfactory input will be critical for our ultimate understanding of how information is encoded and stored within this trilaminar sensory cortex.
  • ItemOpen Access
    Supplementary refuge as a tool for recovering small mammals and reptiles after fire
    (2025) Burns, Heather
    Global fire regimes are becoming more frequent, severe, and extensive. Within Australia, this trend was demonstrated by the unprecedented scale and ecological impact of the 2019-2020 Black Summer fires. Small mammals and reptiles are of particular conservation concern due to their reliance on ground-level vegetation and woody debris, and increased vulnerability to predation in burnt landscapes. Despite the importance of post-fire conservation for these species, there are relatively few evidence-based management interventions available to land managers looking to actively conserve native fauna after fire. In the following chapters I aim to address this knowledge gap by systematically mapping the literature to identify potential post-fire management actions (Chapter 2), and conducting a field-based experiment to test the effects of supplementary coarse woody debris (CWD) on small mammal and reptile populations (Chapters 3-5). In Chapter 2 I used a systematic mapping protocol to identify the range of conservation-focused management interventions that have been used in disturbed landscapes globally. I aimed to identify which management interventions have been used in disturbed landscapes to date and whether those interventions could be suitable in response to other types of disturbance, specifically fire. Interventions were most commonly used to address invasive or overabundant species, agriculture, and production forestry. Coarse woody debris manipulation, predator control and revegetation were the most commonly studied interventions. However, understanding suitable management responses to fire represents a significant knowledge gap and only three studies assessed management interventions in post-fire landscapes. In Chapters 3 and 4 I experimentally tested the effects of supplementary CWD on small mammal and reptile populations in areas burnt by the 2020 Orroral Valley Fire in Namadgi National Park, ACT. In a field-based study I established 20 experimental blocks with three treatments: (1) structure only (CWD piles); (2) predation only (strips of chicken wire); and (3) structure + predation (CWD piles covered in chicken wire). A combination of active and visual searches were used to survey reptile populations at each treatment for two consecutive summer seasons, and wildlife cameras were used to continuously monitor small mammal activity for 15 months. Woody debris treatments (i.e., structure and structure + predation) supported significantly higher abundances of reptiles compared to the control. Small mammal abundance and richness was not significantly greater at any treatment compared with the control, and instead increased most significantly with increasing levels of shrub cover. In Chapter 5 I examined the thermal properties of supplementary CWD piles and compared them to the thermal properties of natural refugia in a post-fire landscape. Temperature loggers were used to monitor temperatures within CWD piles, hollow logs and rocky outcrops across seven months. Temperatures within CWD piles were significantly less extreme than ambient maximum and minimum temperatures. In Chapter 6 I synthesise the findings of Chapters 2-5 to answer the question "what should we do after the next fire?". In this chapter I identify the key lessons learned across my research that can help land managers make more informed decisions after future fires. Overall, supplementary CWD was proven to support a higher abundance of reptiles in areas burnt at high and low fire severity across our study. CWD piles without chicken wire were the most cost-effective treatment tested, and the simplicity of their construction provides an opportunity to involve citizen scientists and community members interested in post-fire recovery efforts.
  • ItemOpen Access
    General Keypoint Detection: Few-Shot and Zero-Shot
    (2025) Lu, Changsheng
    Keypoint detection is a fundamental research topic in computer vision. Despite extensive research on keypoint detection over the past several decades, existing state-of-the-art deep-learning based methods perform well only on specific object types and parts, and struggle to recognize novel keypoints on unseen objects. This close-set detection paradigm limits the model generality to diverse classes in an open-world scenario. Moreover, these models typically require large amounts of annotated data for training before they can recognize a new class, leading to the problem of ``no intelligence without human annotations''. To mitigate above issues, we raise an interesting yet challenging question: how to detect both base and novel keypoints for unseen species given few or even no annotated samples? To answer this question, we have conducted a series of research works as follows: Firstly, inspired by few-shot learning, we introduce a new task called few-shot keypoint detection (FSKD) whose goal is to detect the corresponding keypoints in a query image given one or a few support images with keypoint annotations. Moreover, we propose a versatile FSKD model with uncertainty learning, which can detect a varying number of keypoints of different types while also provides uncertainty estimation for these keypoints. We show the effectiveness of our FSKD on downstream tasks such as few-shot fine-grained visual recognition (FGVR) and semantic alignment (SA). In SA, we further contribute a novel yet realistic thin-plate-spline warping that uses keypoint uncertainty. Secondly, we explore ways to enhance the performance and robustness of FSKD models. To achieve this, we propose a novel visual prior guided vision transformer for FSKD. The visual prior maps are unsupervised and class-agnostic, which helps suppress background noise and encourages context learning on the foregrounds. Moreover, we investigate i) transductive extension of FSKD and ii) FSKD with masking and alignment (MAA), to improve the keypoint representation learning. Thirdly, despite the versatility of existing FSKD models, we observe that there remain two important issues hindering the progress of FSKD, which are i) the scalability issue w.r.t. the number of keypoints and ii) the large domain shift of keypoints between seen and unseen species. To address the first issue, we propose a novel light-weight FSKD model based on simultaneous modulation and detection, which significantly reduces the computational cost without the sacrifice of performance. To overcome the second issue, we improve our light-weight model with the mean feature based contrastive learning (MFCL). Despite simplicity, MFCL promotes invariance learning among the same type of keypoints across different species in noisy scenarios. As a result, the domain shift is bridged. Lastly, if treating the support image and keypoints as visual prompt, we notice that the above FSKD models, basically, align well with the popular ``prompt'' based models used in various vision and language tasks. Consequently, we unified the zero-shot keypoint detection (ZSKD) and few-shot keypoint detection (FSKD) into one framework, capable of accepting either visual prompts, text prompts, or both. We expand prompt diversity across three aspects: modality, semantics (seen vs. unseen), and language, to enable a more general keypoint detection. A multimodal prototype set is proposed to support both visual and textual prompting. To infer the keypoint location of unseen texts, we propose visual and text interpolation, and add the pairs of auxiliary keypoints and texts into training. This significantly improves the zero-shot novel keypoint detection and the spatial reasoning of our model. Additionally, we discover that the large language model (LLM) is a good text parser. By coupling with a large language model (LLM), our keypoint detection model can well handle the diverse text prompts.
  • ItemEmbargo
    Molecular basis for the folding and autocatalytic processing of beta-helical autotransporter passenger domains
    (2025) Yuan, Xiaojun
    Autotransporters are a distinct class of outer membrane proteins (OMPs) and the largest family of virulence factors produced by Gram-negative bacterial pathogens. The virulence functions of autotransporters depend on their correct assembly at the bacterial cell surface. Assembly requires the C-terminal beta-barrel domain to be inserted into the outer membrane in a partially folded state to facilitate translocation of the N-terminal passenger domain onto the cell surface, where it folds into its biologically active form. Some passenger domains remain attached to their cognate beta-barrel domains to typically function as adhesins or as mediators of aggregation and biofilm formation, while others are cleaved and released into the extracellular environment to function as toxins or in disruption of host immune response. Once translocated, autotransporter passenger domains predominantly fold into elongated beta-helical stalk-like structures that project outwards from the cell surface. Many studies have provided valuable insights into how autotransporters adopt their functional conformations, yet many mechanistic details are lacking. In this study, we used mutagenesis analysis to test the role of the extracellular loops of the beta-barrel domain belonging to the autotransporter, plasmid-encoded toxin (Pet) in folding of the cognate passenger domain. We found that the fifth extracellular loop (L5), which forms a beta-hairpin structure, is required for Pet passenger folding into its native, protease-resistant conformation in vivo and in vitro. This work revealed that it is the beta-strand propensity of the L5 beta-hairpin, rather than specific amino acid residues, that is important for facilitating passenger folding. Based on these findings, we proposed that L5 mediates Pet passenger folding via beta-augmentation and showed that this folding mechanism is conserved in the Serine Protease Autotransporters of Enterobacteriaceae (SPATE) subfamily. To test if loop-mediated passenger folding is conserved in autotransporters beyond the SPATE subfamily, we used antigen 43 (Ag43) as a model protein. Ag43 is an autotransporter that mediates cell aggregation and biofilm formation. We found that both the fourth and fifth extracellular loops of the beta-barrel domain are required for rapid folding of the passenger domain and for Ag43-mediated bacterial cell aggregation. Together, these findings suggest that loop-mediated passenger folding could be a conserved folding mechanism among autotransporters with a beta-helical structure. We also show that proteolytic processing of Ag43 occurs through autocatalysis, in the absence of host or exogenous proteases, and that autocatalytic processing of the passenger domain from its cognate beta-barrel is not required for Ag43 function. This study provides new mechanistic understanding of how autotransporter passenger domains fold and undergo proteolytic processing. Our results suggest that the autotransporter beta-barrel domain is a folding vector that mediates passenger domain folding directly via the extracellular loop(s). We show that inhibition of passenger domain folding through deletion of the extracellular loop(s) inhibits autotransporter-mediated virulence functions, and thereby propose that the extracellular loops are potential therapeutic targets in treating and preventing bacterial infections.
  • ItemOpen Access
    Choosing Their Own Path: Uncertainty and the Persistence of Hedging in Southeast Asia
    (2025) Marston IV, Hunter
    Why do states continue to prefer hedging strategies despite persistent threats to their security and growing pressure associated with great power rivalry? Based on detailed empirical analysis of three Southeast Asian countries (Singapore, Vietnam, and the Philippines), this thesis argues that a range of factors explain the persistence of hedging: uncertainty regarding great power competition; mixed views of China; a lack of consensus regarding threats; fear of alienating China; and a preference for self-help strategies or limited alignment over alliances, which create unwanted dependence. Furthermore, this thesis argues that domestic variables, including regime type, bureaucratic institutions, personalities, histories, and leaders' perceptions of threats, produce variations in hedging and the causal pathway to its continuation in the face of security threats and pressures associated with great power rivalry. Thus, external factors explain the persistence of hedging, while internal causes determine its particular expression within each country. This dissertation proposes a Neoclassical Realist theoretical framework of hedging to demonstrate how particular domestic factors account for the unique forms of alignment behaviour in Singapore, Vietnam, and the Philippines. As the dissertation explains, Singapore practices a unique form of hedging which it characterises as "performative hedging," given the importance Singapore places on the appearance of not taking sides, even as it is more closely aligned with the United States based on its history of security cooperation. Vietnam relies on "multidirectional hedging" to maintain positive ties with China even as it deepens its security partnerships with a diverse range of partners in order to preserve flexibility. The Philippines' foreign policy vacillations, by contrast, are better characterised as "underbalancing" as opposed to hedging, given the lack of consistency and purposiveness which the administration of President Rodrigo Duterte (2016-2022) exhibited. Based on the findings from these three case studies, this dissertation makes the following arguments: First, given the prevalence of hedging in the face of direct threats to states' security, hedging should be considered as a valid (if suboptimal) policy response to a threat. Second, hedging is far more resilient under conditions of bipolar rivalry or great power competition than previously assumed. Third, hedging requires both consistency and purposiveness, as the Philippines case study illustrates. This thesis creates new knowledge about the limits and durability of hedging in the face of emerging security threats and new pressures associated with the return of great power rivalry. It also adds greater precision to the concept of hedging, which has been widely used though frequently misunderstood in the International Relations literature.
  • ItemOpen Access
    Three Studies on the U.S. Securities and Exchange Commission (SEC) Comment Letters
    (2025) Wang , WEIXIAO (Steve)
    This thesis presents three studies on the comment letters issued by the U.S. Securities and Exchange Commission (SEC) during its filing review process. I examine three types of comment letters and provide evidence that demonstrates the benefits of the SEC's filing review process. Study 1 examines the impact of compensation-related comment letters (CCLs) issued by the SEC on excess chief executive officers' (CEO) compensation. I find that changes in compensation in the two-year window surrounding the release of CCLs are negatively associated with the number of disclosure defects identified in CCLs, and that this association is driven by defects that relate directly to pay or the method by which it was determined, rather than broader governance- or readability-related defects. Cross-sectional analyses suggest that the negative impact of a CCL on excess CEO compensation is concentrated in firms with overpaid CEOs and less powerful CEOs and firms pursuing prospector-oriented strategies. I further show that total disclosure defects, pay-related defects, and governance-related defects are positively associated with the likelihood that the subject firm experiences low shareholder support in subsequent 'say-on-pay' votes, suggesting that enhanced visibility of excess pay and resulting shareholder activism may be one channel through which pressure is brought to bear on firms to reduce excess compensation. Study 2 investigates whether the qualitative characteristics of firms' narrative responses to the SEC's non-GAAP-related comment letters (NGCLs) are associated with non-GAAP earnings quality, as measured by the persistence of items excluded from published non-GAAP metrics. I find that firms with lower quality non-GAAP earnings that induce a comment letter are associated with less readable firm responses to that comment letter. I further find that the association between the readability of response letters and non-GAAP earnings quality is strongest in cases where persistent expenses other than those relating to special items are included in non-GAAP earnings, and where non-GAAP earnings or growth in earnings are positive and their equivalent GAAP measures are negative. I also show that firms whose responses use less causative language and more positive tones are associated with inferior non-GAAP earnings quality. Additional evidence suggests that firms that provide more readable responses are more likely to follow SEC non-GAAP disclosure requirements by reducing the prominence of non-GAAP earnings in the future. Overall, my results demonstrate that the qualitative characteristics of firm responses to NGCLs contain useful information about non-GAAP earnings quality. Study 3 explores the impact of the SEC's revenue recognition comment letters (RCLs) issued to downstream firms (customers) on the investment efficiency of upstream firms (suppliers). I find that customers' RCLs are associated with more efficient investments by suppliers. The baseline results are robust to a host of analyses to mitigate endogeneity, including difference-in-differences, propensity score matching, entropy balancing, and modified control function regression. Further evidence shows that this association is stronger when the information transfer in supply chain is more likely and for suppliers with an information disadvantage. Additional evidence shows that customers' RCLs are associated with better efficiency of suppliers' investments in capital and R&D and that the severity of customers' comment letters is also related to better investment efficiency of suppliers. Overall, the results suggest that customers' RCLs contain valuable information affecting suppliers' investment decisions.
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