Restricted Theses

Permanent URI for this collectionhttps://hdl.handle.net/1885/9050

While this collection is searchable, the digital copies of the theses are restricted because the author has requested an embargo period or permission has not been given to make the work publicly available.

Browse

Now showing 1 - 20 of 350

Embargo
Psi controls signalling from the Drosophila cortex glial niche to regulate neural stem cell fate
(2024) Muckle, Damien
Glioma patients experience high rates of morbidity and invariable fatality, yet no new, effective treatments have emerged in more than 35 years. Progress in therapeutic development is hindered by a limited understanding of the biology of these heterogeneous brain tumours, which are driven by glioma stem cells supported by a glial niche. Genomic sequencing of the low-grade brain tumour oligodendroglioma identified frequent loss-of-function mutations in the single-stranded DNA/RNA binding protein FUBP1, which are predicted to drive these tumours. However, functional studies investigating FUBP1 function in mammalian systems are complicated by compensatory effects from paralogues within the FUBP protein family, which share common gene binding targets. In Drosophila, the three mammalian FUBP proteins are represented by a single orthologue, Psi, which shares high structural and functional similarity to FUBP1. By taking advantage of this reduced functional redundancy, and the powerful tractability of Drosophila genetics, we dissect FUBP1/Psi function in the cortex glial niche, which functions analogously to the oligodendroglioma niche by providing the structural support and secreted signals which regulate stem cell proliferation and differentiation. Here we demonstrate Psi knockdown specifically in the cortex glial niche of the Drosophila larval brain reduces cortex glial growth and proliferation. Moreover, cortex glial-specific Psi depletion cell non-autonomously drives the proliferation and expansion of otherwise wild-type NSCs. Thus, we present the first evidence that an FUBP family protein functions in a cell non-autonomous manner to control NSC fate. To determine the molecular basis for Psi's capacity to control NSC renewal and differentiation from the supporting cortex glial niche, we used Targeted DamID (TaDa) to identify direct, genome-wide Psi binding targets in cortex glia. We further identified differentially expressed and/or spliced targets via RNA sequencing of Psi-depleted cortex glia and associated NSCs compared with isogenic controls. Intersection of Psi binding targets and transcriptionally altered genes in Psi-depleted cortex glia revealed Psi directly regulates components of major developmental signalling pathways, Hippo and MAPK, among other networks essential for niche function. Our functional genetic studies indicate Psi represses upstream Hippo pathway components in the niche to maintain normal cortex glia growth and proliferation. Furthermore, Psi knockdown directly upregulates EGFR ligand spitz (spi) in cortex glia, which functions in the niche to cell-autonomously regulate cortex glia growth and proliferation. Psi depletion also upregulates another EGFR ligand, gurken (grk), which, in contrast to spi, is required to enable expansion and proliferation of neighbouring NSCs driven cell non-autonomously by loss of Psi. Together, our data demonstrate Psi functions cell non-autonomously in the glial niche to orchestrate signalling networks required to prevent excessive NSC renewal. Thus, given the high degree of functional homology with Psi, we predict FUBP1 loss-of-function drives oligodendroglioma tumourigenesis, at least in part, by dysregulating intra-tumour interactions between the glial niche and glioma stem cells.
Embargo
International politics and construction of climate security by small island developing states: Maldives and Samoa form broader meanings of security
(2024) Rasheed, Athaulla
This research investigates Small Island Developing States' (SIDS) discursive formation of national and foreign policy narratives on climate change as a security concern. It recognises SIDS have played an important role in promoting comprehensive approaches to climate security at the United Nations Security Council debates - these included considering multi-sectoral climate-related threat factors and comprehensive security provisions, including collaborative (whole-of-government) governance approaches to address them. For this thesis, climate security is defined as the ability of states or communities to address and build resilience against climate change in achieving sustainable development, self-sufficiency, and national security. Although it recognising SIDS' engagements in the Security Council debates, the main objective of this thesis is not to analyse their international (climate security) narratives, but instead to present an analytical framework to investigate and portray a domestic construction of climate security by SIDS - using the Maldives' and Samoa's experience - and to explain the domestic narratives driving these countries' national and foreign policy on climate change as a security issue. This thesis asserts that domestic construction helps to make better sense of why SIDS' claim for broader meanings of security becomes important for the Security Council's climate debates, or securitising climate at the international level, and why a comprehensive approach to problem-solving is important in addressing the impacts of climate change on national and international peace and security. In this respect, in adopting a constructivist approach to international relations and security studies, this thesis identifies, analyses, and explains the discourses and identities constitutive of policy narratives that have shaped the climate threat identification and problem-solving approaches adopted in Maldives and Samoa. This thesis analyses the formation of climate policy as a national crisis, threat categories impacting the countries' capacity to achieve sustainable development, and the meaning of security in their island contexts concerning those threats. In that, the intersubjective aspect of the discursive formation of identities and interests explains the interconnectedness or constitutive function of domestic and international policy narratives of states. The domestic interests associated with policy narratives concerning the security implications of climate change can explain both their national and foreign policy drivers. This thesis concludes that the Maldives' and Samoa's cases assert that SIDS become important stakeholders in developing intersubjective narratives to incorporate more holistic and comprehensive aspects of problem-solving into the international peace and security discourse concerning climate change. The Maldives' and Samoa's policy discourses and identities forming climate security narratives, analysed in this thesis, provide a practical framework to explain this.
Unknown
Appropriately Timing Seed Germination- New Players and Upstream Controllers
(2024) Wellawatta Mudiyanselage, Ayesha
Seed germination is a most critical developmental phase change, particularly under abiotic stress conditions such as drought or salinity. The timing of germination plays a major role in setting the timeline of the plant developmental cycle, and in conditioning seedling survival and adaption to unfavourable environments until completion of the plant developmental cycle and successful reproduction. Over recent decades, great progress has been made in understanding seed dormancy, its establishment during maturation on the mother plant, and the factors controlling its release after shedding. In contrast, little is known about the genetic determinants of germination in non-dormant seeds, especially under abiotic stresses. The Arabidopsis ERECTA family AtERf is demonstrated master regulator of various aspects of aerial plant growth and development, and is also involved in responses to environmental stresses, and some immune responses. A recent study (Nanda et al., 2019) uncovered another, unsuspected function, especially in the sensitivity of seed germination to salinity and osmotic stress. The germination of seeds with reduced ERECTA family signalling was found to slowed down, delayed or even halted by salinity and osmotic stress, through largely reversible mechanisms, so that when conditions became more favourable again, germination generally resumed, without significant loss of seed viability. That adaptive function was shown to be primarily under maternal control, and to involve the three family members, with specificity, among ERf members. The present study followed from that work, with a two-fold aim: a) Better understand the physiological and molecular bases of the maternal inheritance of the ERf-mediated germination phenotype; b) Test conservation across species of the newly discovered ERf regulatory function in Arabidopsis seed germination, with a focus on barley (Hordeum vulgare, Hv), a major staple food and pillar of the brewing industry. The first Chapter of this thesis describes the discovery of a novel molecular interactor of the Arabidopsis AtERf - the MYB family transcription factor AtGL1- previously unknown to be acting in seeds, nor to interact with the extensively documented ERf signalling pathways in aerial organs. GL1 is here shown to synergistically interact with the ERf members, in a gene combination-dependent manner, to regulate the initiation, progression, and timing of germination completion under saline conditions. A second Chapter reports on a genome-wide analysis of ERf- and GL1-mediated changes in transcriptional networks during early seed development and differentiation through RNAseq analysis of developing siliques. The results indicate that wide-spread ERf and GL1 separately act and also interact in the transcriptional control of hormone signalling, transcription factors, cell wall biogenesis, the formation of cuticular and wax compounds, stress response pathways. The last part of the thesis presents the analysis of a range of barley mutant lines obtained through CRISPR-Cas9 editing of the putative barley HvERf and HvGL1 orthologues. They show that these genes, separately and together, exert a major regulatory role in vegetative development, fertility and the anatomical and structural characteristics of the maternal seed enclosing tissues, and in the regulation of seed germination under salinity but also constitutively. In conclusion, the findings reported in this thesis overall highlight the potential of the barley ERECTA genes and putative orthologue to AtGL1 for genetic improvement, especially with respect of more uniform germination within seed cohorts, and regulation of its timing to mitigate risks of germination failure or seedling death, thus enhancing yield.
Unknown
A Change In The Field: Australia-India cricket and the possibilities for cultural openness in the shadow of colonialism
(2024) Piggott, Geoffrey
A common view in the discourse of Australia-India cultural relations is that for a more meaningful relationship to develop, Australia must move beyond approaching India through the prism of practices which have their roots in the two countries' shared - but contrasting - history of British colonialism. Cricket, it is often said, provides a shallow point of connection and acts as a reminder of the racial and cultural injustices of Empire. This thesis problematises such received wisdom. It begins from the premise that while there is little doubt that a colonial lens limits Australian understandings of India, cricket continues to be a major point of popular cultural contact between the two countries, and has, in the last three decades, moved beyond the colonial power dynamics of its past as India has become the pre-eminent force in the sport. In light of this, this thesis asks how and to what extent cricket might move Australia-India cultural relations beyond their mediation through the echoes of the British Empire and foster a disposition of greater cultural openness from Australia towards India. It presents a detailed study of media representations and in-depth interviews with commentators, journalists, administrators and players, examining how India's rise to power in cricket was negotiated in Australia. Through analysis of a series of ruptures in the sport during the late 1990s and early 2000s, the thesis charts how long-maintained Australian narratives of Indian racial and cultural inferiority were rendered unsustainable by India's exercise of its newfound power. This was due, I argue, partly to the specificities of sport as a cultural field, its lusory nature providing space for changes in Australian attitudes, and partly to the impact, in Bourdieuan terms, of the economic field on the cultural, with India's economic power changing fundamental aspects of the form of the sport. The shift in cultural power opened new possibilities and posed still unresolved challenges for Australian cricket and the broader Australia-India cultural relationship. On one hand, the period of conflict, ironically, established a site of nostalgic memory which now provides a meaningful point of connection between the two countries. On the other hand, the changes in the form of the game mean that cricketing traditions which have positioned it as part of the Australian national imaginary are threatened, and that the financial health of the sport is tied to a hyper-commercial and increasingly politicised Indian cricket establishment. Through my research, in addition to adding to the discourse of Australia-India relations, I add to contemporary debate in cultural studies and postcolonial studies. I propose that, for all the game's colonial history and contemporary neo-liberal capitalist logic, the changes in cricket are an example of how formerly colonial cultural practices can, in complex and imperfect ways, move beyond their racially hierarchical histories, act as a shared point of reference across national-cultural boundaries and provide a site for the development of attitudes of cultural openness.
Unknown
Additive Manufacturing Based on Electrochemistry
(2024) Viktorova, Jekaterina
A fabrication method combining 3D printing and multi-material electrodeposition is introduced in this thesis. The method combines electrochemical and three-dimensional control of electrode positions to culminate in a new process for 2D patterning and the 3D printing of metals, semiconductors, as well as polymers into complex shapes with feature sizes as small as 10 um. The method specifically allows access to patterned or printed, previously difficult-to-process electrically conductive pi-conjugated polymers. The technique uses electrodes in a solution of an electrodepositable material to perform electrochemical printing, a process that can be controlled by varying the inter-electrode gap, the applied potential or current, the electrode geometry and dimension, the electrodeposition solution (ink), movement direction, and movement speed. The first chapter introduces the concepts of electrodeposition and localized electrodeposition and applies them to electrochemical printing. It also explores the influence of the different parameters which affect the printing process and introduces the types of materials that can be printed using this method. In Chapter 2, electrochemical printing is shown to have a unique combination of speed and resolution, multi-material printing, and morphology control, culminating in multi-material device fabrication. In Chapter 3, the first steps are made in monitoring the electrochemical reactions and localized deposition processes in-situ by combining electrochemical analytical methods such as cyclic voltammetry and chronoamperometry with electrochemical quartz crystal microgravimetry. Using poly(3,4-ethylenedioxythiophene) (PEDOT) as a model system, we study the effects that the composition of the supporting electrolyte and solvent used, de-oxygenation and monomer concentration had on the polymerization yield. In Chapter 4, a brand-new approach involving the ferrocene-mediated cationic electrochemical printing of bisphenol A diglycidyl ether and tris[4-hydroxyphenyl] methane triglycidyl ether) based on electrochemically controlled ring-opening polymerization is demonstrated. The development of this novel fabrication method combining 3D printing and multi-material electrodeposition opens new pathways for advanced material design and manufacturing. By enabling precise, controlled deposition of metals, semiconductors, and conductive polymers in complex 2D and 3D architectures, this technique can significantly enhance applications in fields such as flexible electronics, biosensors, and energy storage devices. The ability to pattern previously hard-to-process conductive polymers also presents opportunities for innovations in organic electronics and optoelectronic devices. The versatility and scalability of this method position it as a promising platform for future research and development in multi-material printing and electrochemical manufacturing, potentially unlocking the production of functional materials and devices.
Embargo
Characterisation of the Transcriptome and Proteome of Residual Bodies and Uncovering of a Non-Canonical Role of the Histone Variant H2A.B3 During Spermatogenesis
(2024) Apu, Nazmul
Spermatogenesis is a process where male germ cells undergo morphological changes to become motile and fertile spermatozoa. Key changes include the shrinkage of the nucleus, development of the flagellum, and extrusion of most cytoplasmic contents into the lumen of the seminiferous tubules in the form of Residual Bodies (RBs). Conventionally, RBs were thought to be phagocytosed by Sertoli cells (SCs). However, recent evidence challenges this view, highlighting a more intricate utilisation of RB contents. Specifically, H2A.B3, a spermatid-specific histone variant known for its positive regulation of germ cell transcription, is preserved in a full-length non-chromatin-bound form within RBs. Remarkably, upon RB absorption, H2A.B3 is detected in the nucleus of SCs. Intriguingly, the H2A.B3 KO mouse exhibits tubules congested with the cytoplasmic content of maturing spermatids and defective SC phenotypes. This suggests a novel epigenetic information transfer mechanism between germ and Sertoli cells mediated by RBs, where H2A.B3 potentially acts as a chaperone to transport germ cell-specific factors to SCs. The first aim of the thesis was to establish an improved purification method for RBs from mouse seminiferous tubules. Chapter 3 introduces a continuous sucrose gradient ultracentrifugation-based method, enabling the isolation of up to 98% pure RBs from only 1 g of testis tissue. Morphological characterisation of RBs using RB-specific EMA staining and transmission electron microscopy (TEM) revealed that the tubules of H2A.B3 KO mice contain a more dispersed form of RBs with a different size distribution, suggesting delayed RB absorption by SCs and slower tubule differentiation. Furthermore, H2A.B3 KO RBs demonstrated more filled vacuoles of lysosomal nature compared to WT, implying defects in lysosomal clearance. The second aim, explored in Chapters 4 and 5, was to comprehensively characterise the transcriptome and proteome of RBs, respectively. Using Nanopore RNA-sequencing (RNA-seq), diverse classes of biologically important RNA were identified in RBs, with a significant overrepresentation of replication-dependent histone genes in H2A.B3 KO RBs. This implies a defective chromatin compaction process, as evidenced by a higher sperm chromatin density in H2A.B3 KO mice. Additionally, H2A.B3 was found to be involved in splicing, showing a preference for first and last exon inclusion. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomic study of RBs detected 3,226 proteins, which are mainly involved in protein transport and metabolism. Our investigation also reported the presence several histone proteins in RBs for the first time. Moreover, RBs contain nine unique H2A.B3-interacting proteins, the majority of which are associated with splicing. The third aim of the thesis, explored in Chapter 6, was to investigate the role of H2A.B3 in RNA degradation. A newly developed bioinformatic pipeline was used to measure and compare the 3'- and 5'-end degradation levels of replication-dependent histone mRNA transcripts between WT and H2A.B3 KO across various spermatid stages and RBs. The 3'-end of replication-dependent histone mRNAs was the most degraded in early-round spermatids of H2A.B3 KO mice, whereas the 5'-end remained mostly unaffected, which was also validated by overexpressing the H2A.B3 protein in Neuro2a cells. In summary, this thesis presents a modernised RB purification method, aiding in understanding RB biology and the crucial roles played by H2A.B3. The findings lay the groundwork for investigating broader hypothesis regarding epigenetic information transfer between germ cells and SCs via RBs. Additionally, a novel non-canonical role of H2A.B3 in the degradation process of replication-dependent histone mRNA is uncovered, further expanding our understanding of spermatogenesis.
Embargo
In Situ Oxygen Isotopes and Water Concentrations: Analytical Developments and Applications to Extraterrestrial Materials
(2024) Patkar, Aditya
O-isotopes of chondrules, CAIs, and matrix commonly show variable 16O abundances. A 16O-poor aqueous or water-ice reservoir is thought to have influenced their primary isotope ratios. This study explores the interrelationship between O-isotope systematics and total water contents (H+OH+H2O) in components from carbonaceous chondrites, pallasites and asteroid Ryugu samples using the SHRIMP SI ion microprobe. Analytical development is needed to measure in situ water in meteoritic NAMs, and three O-isotopes in the hydrated chondrite matrix because of the presence of a large 16O1H peak. Techniques were developed to reduce instrument water background and reliably measure water content <100 ppm, employing various sample preparation methods and introducing a Bi-Sn alloy as an alternative to In mounts. Terrestrial minerals with varying water contents were used to quantify the tailing from 16O1H under the 17O peak. Minerals show D17O residuals systematically related to the 16O1H peaks suggesting consistent tailing, and a tailing correction has been proposed. Thirdly, IMF bias was determined in a suite of olivine reference materials over the entire Mg/Fe compositional range. CC chondrules show variable O-isotope ratios with most type I olivine (Mg#>90) are isotopically lighter reflecting reducing conditions, higher T, and lower dust:gas, whereas type II olivine (Mg#<90) that formed in an oxidising, dust-rich environment are isotopically heavier. In contrast to previous studies in chondrule NAMs with a large range of ~8 ppm to ~1 wt% water, our results in >250 olivine grains from chondrules and isolated matrix grains are much lower. Similar to O-isotope dichotomy, forsterites (Mg# >98) from CM, CO, CV chondrites contain a median of 4.6 +- 3.7 (1SD) ppm water, while type II olivine (4450 permil. However, CAI phases from CV finds show several 1000s of ppm water, potentially originating from small fractures that pervade the CAIs, especially melilite, suggesting terrestrial alteration. Lower water in clean regions of melilite from CV chondrite finds and in the rejected spots from Allende CAIs that overlap fractures suggests that the fractures from CV finds may contain localised incipient hydrated products. The low water data in Allende CAI phases suggests a nebular origin and similar P-T conditions which is consistent with our current understanding of CAI formation and evolution. Hydrated matrix from CM, CI, CY chondrites and asteroid Ryugu reflects extensive aqueous alteration. Bulk O-isotope ratios in the hydrated matrix dominated by serpentine-saponite show large IMF effects likely controlled by Mg/Fe variations. Bulk CM2 matrix shows D17O values ranging from -1.6 to -2.5 permil compared to whole-rock values which range between -2 to -4 permil. In contrast, matrix from CI and CY chondrites and Ryugu shows a D17O range overlapping with the whole-rock values. The large D17O scatter can be partly attributed to uncertainty in tailing correction but also possibly reflects the intrinsic isotopic heterogeneity of the chondritic matrix.
Embargo
Wild Goose Tracks in the Snow: An Illustrated Record of my Preordained Life by Wanyan Linqing (1791-1846): a nineteenth-century memoir
(2024) Sanderson, Christina
Wanyan Linqing (1791-1846) was a Manchu Bannerman who travelled throughout China as an official in service of the Qing Court. In his later years he acquired and moved into a renowned garden-mansion in Peking, where he composed an autobiographical memoir in classical Chinese, Hongxue yinyuan tuji (Wild Goose Tracks in the Snow: An Illustrated Record of my Preordained Life), recording, in two hundred and forty chapters each accompanied by a woodblock illustration, as many moments of his life deemed to have been the most memorable. During the 1980s, the first one hundred and seventy chapters of this memoir were translated and annotated in Hong Kong by Mongol Bannerman Professor Yang Tsung-han (1901-1992). Under the guidance of Professor John Minford, Christina Sanderson has recently compiled the first complete translation and annotation of this work, by editing Yang's existing translation and commentary and translating and annotating the final seventy chapters. This thesis is a reflection on that memoir, and on the process of its translation. It argues that Tracks in the Snow is a remarkable window into the world of traditional China. To prove this, it presents several different ways of reading the memoir, including from a biographical and historical perspective, and in the context of literature.
Embargo
Road from Rebetiko: Explorations in the Fusion of Jazz and Traditional Greek Urban Music
(2024) Campbell, Constantine Robert
This project is a research-led hybridity experiment in creative practice, fusing jazz and Greek rebetiko. The thesis explores the history and nature of jazz fusion - or hybridity - with a view to understand its significance for the genre of jazz and to position the rebetiko-jazz fusion experiment within it. The thesis also explores the history and nature of Greek rebetiko music in order to pay homage to its traditions, heritage, and musicians, and to embrace its spirit and learn from its mechanisms for the purpose of hybridity. Finally, the thesis offers an exegesis of creative practice, which describes the inspiration, methods, processes, and outcomes of this rebetiko-jazz fusion experiment, which culminates in twelve original compositions that have been performed and recorded across two albums. I conclude that my creative practice is a glocalised expression of both jazz and rebetiko.
Embargo
Quantifying porphyry copper deposit fertility from zircon geochemistry using predictive modelling: from theory to applications
(2024) Carrasco Godoy, Carlos
The demand for copper in the next 20 years is expected to be equal to its total historic production due to copper's fundamental role in the transition to green energy. Porphyry copper deposits are the source of 75% of the world's copper but the rate of discovery of new deposits has declined over the last decade. Zircon is an accessory mineral that is resistant to chemical weathering and physical abrasion. It is common in siliceous igneous rocks, including those associated with porphyry copper deposits. Zircon's chemical composition can provide information about the magma it crystallizes from and potentially be used to distinguish ore-forming porphyry magmas from barren magma systems. This thesis covers three projects aimed at understanding how zircon geochemistry can be used in porphyry Cu exploration. The first presents an empirical method, based on Onuma diagrams and the lattice strain theory, to calculate missing rare earth elements (REE) and Y data in legacy datasets in which some elements were not analysed. The results have been calibrated against known concentrations, and lattice strain theory estimates, using a dataset of ~1,500 zircons with no missing REE + Y concentrations. The results show that REEs can be confidently imputed with as few as five REEs and allow the estimation of La, Pr and Ce* in zircons with greater confidence than traditional methods. These methods enable the reconciliation of old and new REE + Y data. The second project is a data-driven analysis of zircon geochemistry that compares those that formed in magmas associated with porphyry copper deposits with those that formed in barren magmatism. This study compiles a database of more than 23,000 zircons from > 30 porphyry copper deposits, barren sources and rivers and uses machine learning for classification and comparison with traditional geochemical thresholds. The study confirms some of the zircon fertility indicators proposed in the literature (Eu/Eu*, Dy/Yb, Ce/Nd), discard those that are not diagnostic (Hf, Th/U), and proposes two new fertility indicators (P and shape of the REE pattern). It also shows that random forest models outperform traditional geochemical methods by correctly identifying up to 20% more fertile zircons. Shallow machine learning algorithms outperform the traditional geochemical discriminators and provide insights into characteristics that have not previously been considered when evaluating porphyry copper fertility using zircon geochemistry. The last project is a test case of zircon fertility classification using random forest in the world's most prolific porphyry copper region: the Loa River drainage basin, Northern Chile, that includes the Chuquicamata, El Abra, Collahuasi, Spence and Sierra Gorda porphyry districts. Nearly 1,600 zircon grains, collected along the Loa River basin, were analysed for trace elements, geochronology, and their class membership probability (fertile or barren) calculated using predictive models. The results indicate that periods with higher zircon frequency coincide with the ages of the magmatic arcs in the area. Furthermore, the age of the deposits matches the end of these periods and is accompanied by an increase in the number of zircons classified as fertile. There is also an increase in the fraction of fertile zircons in samples collected close to deposits, which reach their maximum near the El Abra deposit.
Embargo
White Fantasy, Indigenous Sovereignty: Tools for an Ethics of Representation in Settler-Colonial Creative Writing Practice
(2024) Stevens, Rosanna
"White is a colour. A page is not a neutral cultural object. The white imagination is indeed colour blind. It is blind to its own colour - whiteness; and to its own cultural standpoint that is neither neutral nor universal." - Jeanine Leane (2021, para. 26) First Nations scholars and writers have spent considerable time and thought critiquing mainstream methods with which white Australian writers tell stories about Aboriginal and Torres Strait Islander Peoples, issues, culture and Country. While some white settler-colonial writers and scholars have responded to the authority of First Nations knowledge holders and makers, the uptake of Indigenous instruction in wider settler-colonial creative discourse remains limited. Nonetheless, white desire to tell stories that 'get it right' in representing Indigeneity has remained and intensified in anxiety, without significant questioning among white writers about what 'getting it right' is, who determines this achievement, whom it serves, and what that means. In this thesis, I present how I have used my creative practice and positionality as a white colonial-settler middle-class woman, to participate in this questioning. This PhD project articulates how attempts at representing First Peoples become political projects as I see and understand myself, my concerns, my creative practice and my words in the context of colonising racial categories, and the insistence and values of unceded Indigenous sovereignty. As a result of this questioning - guided by critical race and whiteness studies, Indigenous-led literary and knowledge production studies, and phenomenological cultural studies - I develop five conceptual tools that decentre the goal of representational perfection of Indigenous subjects from white subjectivity, on the grounds that this is a false, and colonising, project. Instead, these conceptual tools - of unfinishedness, apology, honesty, contextualisation and turning - support a practical, lived redefinition of what it means to be a writer who is accountable to those with a vested interest in a story. This thesis contributes to understanding how, in the context of Indigenous sovereignty, settler-colonial storytellers might realise and loosen the tight grip of normative narrative production that encourages a closed, hurried, and possessive creative and representational practice.
Embargo
Exercise of adaptive leadership by senior officials in the Australian Public Service as a Westminster institution
(2024) McMahon, Robert
Framed by tensions between Westminster conventions and traditions, and public servants' values, craft obligations and felt responsibility, the research explores how Senior Executive Service (SES) officers in the Australian federal government make use of a specific leadership model, adaptive leadership (AL), in conceiving and performing their roles. The kernel for the study is that AL, adopted by the Australian Public Service Commission in 2012 to develop its SES cadre, evinces particular entrepreneurial characteristics which may not be a natural fit in the Australian Public Service (APS) as a derived Westminster institution with inherited conventions, traditions and understandings. While traditional formulations posit that Westminster public services operate along dichotomous responsibility-accountability conventions and principal-agency relationships, these accounts fail to sufficiently acquit the role of the public service in an increasingly complex environment. Conceptually, this study explores the role of the public service as an institution with a form of independence adapting to changing responsibility and dispersed accountability, including an increased relationship between senior officials direct to the parliament. Empirically, the study examines subsidiary questions about how, and in what circumstances, public officials exercise AL, and whether they do so in modified forms depending upon organisational setting. Emerging from this exploration was a distinct set of leadership conditions -- a 'native' leadership craft -- used by SES officers to make sense of and navigate their environment: a "habit of discernment" to bridge knowing the right thing to do and acting to do it. To explore for the prevalence of AL against the normative backdrop of the APS's role in the Westminster tradition, the research employs a mixed methods approach involving interviews with dozens of elite (political and administrative) actors, APS SES officers and observer-stakeholders; grounded in three organisation-level case studies to observe the possible situational variation of AL. It also draws on a large bank of primary and secondary documentary material--speeches, press releases, parliamentary debates, reports, guidelines, monographs and journal articles. This research is relevant conceptually and timely in practice. Along with other nations, Australia faces a set of difficult challenges ahead, not least managing the social and economic aftermath of historic pandemic crisis, extant international strategic and economic pressures, and domestic policy challenges. Effective leadership by senior officials will therefore be critical to navigate these pressures. In light of the research findings, the study proposes changes in SES leadership development policy and practices to support senior officials navigate their evolving environment.
Embargo
The role of TREX-2 complex in nucleo-cytoplasmic mRNA export
Kim, Yoona
Eukaryotic cells display compartmentalisation within the nucleus and cytoplasm, regulated by nucleo-cytoplasmic transport (NCT). This process is essential for the movement of functional molecules, with the nuclear pore complex (NPC) acting as a selective barrier. While the karyopherin family oversees the transport of most macromolecules, mRNA export follows a distinct route mediated by Mex67-Nxt1 in S. pombe and Nxf1-Nxt1 in humans, recognised as the sole mRNA export receptors with evolutionary conservation. Although current models propose the recruitment of Transcription and Export complexes 1 and 2 (TREX-1 and TREX-2) to mRNAs during transcription elongation, delivering them to the Mex67-Nxt1/NXF1-NXT1 transport receptor, the non-essential nature of Mex67 and Nxt1 genes in S. pombe suggests the existence of alternative mRNA export receptors. In this study, we discovered the intriguing role of the TREX-2 complex as an mRNA export receptor, facilitating the transit of mRNAs through the nucleopore channel. Our results demonstrate that the TREX-2 complex functions as an mRNA export receptor, despite its anchorage to the nucleoplasmic side of the NPC via the extended C-terminal domain of the Sac3 subunit, known as GANP in humans. Our research revealed that the TREX-2's head-domain, consisting of the N-region with FG-like repeats and the mRNA-binding M-region, can extend to the cytoplasmic side of the NPC. Furthermore, we demonstrated a strong correlation between the head-domain of TREX-2 complex and messenger ribonucleoproteins (mRNPs) during nuclear translocation, independent of Mex67. The research posits a dynamic model in which the TREX-2 complex and mRNPs move conjointly through the NPC's FG-repeat framework. While this coordinated migration occurs, the TREX-2's tail-domain is consistently anchored to the nuclear side, signifying an existence of a distinctive pathway for the nuclear export of mRNA, one that does not solely depend on the traditional transport receptor Mex67-Nxt1 (NXF1-NXT1 in human). Furthermore, we explored the functional role of a newly identified protein complex, namely the Sac32-Pci2-Dss1 complex. Our findings indicate that Sac32 shares conserved homology with Sac3, similar to the Sac3 subunit of TREX-2 complex, and its structural arrangement is preserved across a range of eukaryotes from S. pombe to higher organisms. Our investigation revealed that Sac32 predominantly localises in the nucleoplasm, in contrast to TREX-2 complex, which is situated at the nuclear periphery. The deletion of sac32 and pci2 resulted in the accumulation of mRNA within the nucleus, indicating that the Sac32-Pci2-Dss1 complex may function as a mobile version of the spTREX-2 complex, contributing to the mRNA export. Remarkably, our observations indicate that Sac32 is capable of migrating towards the nuclear periphery where it potentially interacts closely with the head-domain of the TREX-2 complex. This suggests a role for Sac32 in facilitating the transfer of mRNPs to the TREX-2 complex for nuclear mRNA export. Finally, our extensive genome-wide analyses revealed that TREX-2 complex binds to mRNAs globally, while TREX-1 complex exhibits both global and selective interactions with mRNA molecules. Additionally, our findings suggest the potential involvement of Sac32 in co-transcriptional mRNA processes. Our study presents the 'lasso model' where the TREX-2 complex is essential for bulk mRNA export, engaging after mRNPs dock at the nuclear basket facilitated by nuclear export factors like TREX-1 complex, Sac32-Pci2-Dss1 complex, or Mex67-Nxt1. The TREX-2's head-domain actively transports mRNPs to the cytoplasm, while the tail-domain remains fixed at the nuclear basket. Our findings introduce a new paradigm for mRNA export, challenging the traditional view of the only mRNA export receptor and revealing a previously uncharacterised transport pathway within the NCT system that operates independently of established shuttle proteins.
Embargo
YAP activation in the skin promotes an inflamed and immunosuppressed microenvironment
Garrett, Jessica
The success of cancer immunotherapy is highly dependent on the tumour microenvironment. Tumour responsiveness to immune checkpoint inhibitors depends on potentiating cytotoxic T cell activity, but this can be blocked by the presence of immunosuppressive cells in the microenvironment which interfere with normal T cell function. Understanding how to combat immunosuppression and resensitise tumours to immunotherapy, is the focus of current research efforts. The oncogene Yes Associated Protein (YAP) has a well-established role in cancer growth and metastasis. Separate to cancer, there is an emerging role for YAP in the development of chronic inflammatory diseases and fibrosis. Given this, I sought to define the cellular and molecular immune responses driven by YAP hyperactivation in the skin, with the intention of understanding how oncogenic YAP might influence the tumour microenvironment. Two mouse models were characterised, where YAP was constitutively activated in the basal keratinocytes of the epidermis (K5>YAP5SA and K5>Lats1/2-/-). YAP activation resulted in keratinocyte hyperproliferation, thickening of the epidermis and the development of a dermatitis-like skin phenotype. Analysis of the skin immune contexture, facilitated by Flow Cytometry and single cell RNAseq, revealed a strong infiltration of myeloid cells (dominated by neutrophils), with a gene expression profile characteristic of myeloid derived suppressor cells. In the lymphoid compartment, CD4+ T cells and NK+ cells were significantly increased in YAP-activated skin, without a corresponding increase in cytotoxic CD8+ T cells. Infiltrating CD4+ T cell populations included both conventional, helper and immunosuppressive Treg subtypes. Corresponding analyte analysis, performed on plasma from both YAP-activated models, revealed a cytokine profile characteristic of chronic inflammation and immunosuppression. Importantly, in vivo growth of a syngeneic murine melanoma cell line was significantly accelerated when implanted in K5>YAP5SA mice. Taken together, these data identify a non-cell autonomous role for YAP in influencing the immune contexture of the skin, marked by features of cellular and molecular immunosuppression. Furthermore, the protumorigenic potential of the YAP-driven immune contexture, identified here, warrants further investigation in the immune-oncology space.
Embargo
Advanced Luminescence-Based Characterization Techniques For Perovskite Solar Cells
Bui, Anh
This thesis focuses on the comprehensive characterization of hybrid organic-inorganic perovskite-based solar cells (PSCs). Despite impressive advancements in perovskite-based solar cell research, resulting in certified power conversion efficiencies (PCE) of up to 26% for single-junction cells and 33.7% for monolithic perovskite-silicon tandem solar cells, further efforts are essential for commercializing this technology. A key challenge lies in the non-uniformity of the perovskite layer, which can serve as a degradation center during long-term operation and limit the device's original performance. To address this limitation, a series of novel characterization techniques based on photoluminescence (PL) imaging have been developed to spatially resolve crucial optoelectronic parameters, such as implied open-circuit voltage (iVoc), pseudo-fill factor (pFF), ideality factor (nid), and series resistance (Rs). The correlation between these parameters enables a profound understanding of device performance losses and their origins. In the first part of the thesis, we employ generalized Planck's law to convert the relative detected PL signal to quasi-Fermi level splitting (QFLS), representing the implied open-circuit voltage. We calibrate the halogen lamp with known absolute intensity to accurately calculate the scaling factor (SF) accounting for the detected light fraction. Our approach is validated through various independent techniques, including lifetime-calibrated PL, spectrally resolved PL, and comparison with terminal Voc. We apply this method to spatially resolve iVoc of different devices, encompassing bare perovskite films, perovskite top cells, and silicon bottom cells of tandem perovskite-silicon solar cells. The VOC loss due to non-radiative recombination and energy band alignment is subsequently calculated, providing a vital target for the fabrication process. In the second part of the thesis, illumination intensity and temperature-dependent PL imaging are employed to extract various optoelectronic properties of PSCs, including pFF, nid, and activation energy of recombination (Ea). The pFF parameter, which represents the fill factor of the device without series resistance, is used to evaluate the potential PCE of PSCs, offering the second target for the fabrication process. The PL-based method's contactless advantage enables the study of different layers and fabrication processes' effects on device performance, providing valuable insights. nid and EA help predict major non-radiative recombination mechanisms, offering further understanding of the performance loss origins. Additionally, correlations between these parameters are investigated for devices before and after degradation tests. In the third part of the thesis, we investigate the PL intensity at different terminal voltages, including open-circuit, maximum power point, and short-circuit conditions, to calculate the PCE image and the series resistance (Rs) image. A strong correlation between PL quenching and PCE is observed, highlighting the significance of PL intensities in assessing device performance. However, a weak correlation is found between the PL image intensity under open-circuit conditions and the final PCE, emphasizing the risk of misinterpreting device performance based solely on PL intensities. Furthermore, we demonstrate the impact of voltage-dependent series resistance on device simulation accuracy, underscoring another crucial contribution of luminescence imaging to the perovskite solar cell technology's research and development.
Embargo
Power Centralisation and Economic Diversification: The Political Economy of Saudi Arabia Based on Vision 2030
(2024) Alhumaidi, Khalid
Since the oil boom in the 1970s, the strategic focus of the Kingdom of Saudi Arabia (KSA) has been firmly centred on the pursuit of economic diversification beyond oil. Despite recurring efforts since the 1970s, the Kingdom's diversification strategies exhibit a cyclical pattern, strengthening in response to declining oil prices and subsequently receding when oil prices rebound, raising questions about persistent challenges to diversification. Numerous views have been proposed to explain this dilemma; however, they tend to overlook a critical aspect: the complex nature of the Saudi regime's power structure. In January 2015, King Salman's accession to the throne, coupled with Crown Prince Mohammed bin Salman's ascendance as KSA's de facto ruler, marked a turning point, leading to the launch of Vision 2030, which aims to reduce the economy's dependence on oil. Since then, KSA has seen significant shifts in its economic, social, and political fabric under Vision 2030. This thesis investigates the impact of the Crown Prince's centralisation of power on the implementation of Vision 2030. This thesis is based on field research in KSA. The methodology encompassed a spectrum of data collection techniques, including over 100 interviews with ministers, government officials, members of the royal family, development advisors, academics, and citizens, coupled with the analysis of primary sources. This thesis argues that power centralisation under the Crown Prince has brought an end to state fragmentation, a trait that facilitated inefficiency within the Saudi bureaucracy for five decades. The subsequent implementation of Vision 2030 has spurred increased government efficiency and expedited economic diversification initiatives in the industrial, investment, tourism and entertainment sectors and in initiatives such as the Aramco initial public offering. On the other hand, the implementation of Vision 2030 is not without challenges. The long-standing influence of the rentier economy has complicated the swift implementation of Vision 2030, especially through inherited challenges such as public sector expansion and private sector fragility, while emerging challenges like the absence of a political framework, mega projects, and an undefined economic structure have also impeded implementation. By evaluating the historical context of economic diversification, this thesis examines the period from the post-2015 era until 2022. It argues that centralisation has facilitated bypassing bureaucratic hurdles and diminishing the influence of narrow interest groups. This significant change, essential for advancing the agenda of economic diversification under Vision 2030, marks a departure from the Kingdom's politics pre-2015. This thesis concludes that the Crown Prince's centralisation of power has positively influenced economic diversification efforts based on Vision 2030.
Embargo
Power and Dependency: the Ambiguous Reality and Norms of the Rich in China
(2024) Wang, Jasmine
I adopt a multi disciplinary approach spanning anthropology, sociology, philosophy, history, and political science. Confucianism was the official ideology legitimizing authority in traditional China, but the central philosophy is Legalism. Qin Hui describes the Chinese past as "Legalism masquerading as Confucianism" where power is absolute, defining the cultural and political situation in China. I use the entrepreneurs as a prism to explain Chinese politics and culture. China's first capitalist experiments with a market economy was introduced in the early 1980s, and I follow the ups and downs of the entrepreneurs since then. They are used as both the vehicle of wealth and as a scapegoat of trouble for the CCP; praised as heroes and blamed for alleged "original sins". I use Van Gennep's concept "Liminality" in a wider meaning as it has expanded into wider social and political theory. Victor Turner described liminality as "a state of betwixt and between". The Chinese entrepreneurs can be seen, not as a class, but as being in a liminal state, betwixt and between power and dependency. Hidden and unwritten norms regulate this situation. Such norms represent the hidden agenda of the powerful. The entrepreneurs must be skillful at maneuvering through such a system of hidden norms. I interviewed forty wealthy entrepreneurs. I use ethnomethodology as a way to describe the "unequal social encounters" my interviewees were experiencing in their state of liminality. Anxiety and insecurity often dominated. Strategies of caution became central. Issues of law, nationalism, democracy, family and gender, citizenship and residency, class, poverty, and money worship were part of their narrative. Today's "red elites" do not allow their arbitrary power to be caged by bureaucratic rules. The Chinese system does not follow Weberian rationality as "red elites" can "soften up" the process through cultivating informal relations and loyalty to cement the effectiveness of their political rule. I link this to James March's theory of "organized anarchy". The entrepreneurs are both demonized and idealized. They are used by political power as negative or positive models whenever necessary. "The nomenklatura system" is an upward accountability system, causing the pervasiveness of informal institutions, where informal social relations dominate. Chinese bureaucracy is about personal loyalty, trust, and patron-client relationships. Weber explained the "charisma of office", contrasting it to "original charisma". In China, the "original charisma" of Maoism has changed into "routinized charisma". This form of charismatic authority is based on legitimization through economic reforms rather than ideology. The financial clique (jinrong bang) describes the financial technocracy in charge of the Chinese financial system. This clique constitutes a complicated web of connections through family lineages as well as economic expertise. They form an opaque web of connections difficult to challenge by the party leadership. I term this situation an "emperor's paranoia". Where there is power, there is resistance. I discuss Scott's "hidden and public transcripts". The entrepreneurs often juggle different transcripts because of their state of liminality between power and dependency. They are unlikely to initiate attacks on the power system and cynical in their confrontations and collusions with power. I also discuss the norms of cynicism in China as a systemic or structural cynicism rather than a moral issue as such. Scott's concept of "political electricity" forms my argument about potential sudden change. I end my thesis discussing the potential breakdown scenarios and the constant winds of change.
Embargo
Ruthenium alkynyl-terminated ladder-type oligo(p-phenylene)s
(2024) Sabu, Anagha
The field of nonlinear optics encompasses interactions of electromagnetic fields(light) with matter, these interactions change the nature of the incident light such that new fields with differing phase, frequency, amplitude, polarization, path, or other propagation characteristics are produced. Materials which possess nonlinear optical (NLO) properties are of technological importance in areas that utilize optical devices, with potential applications such as microfabrication, bioimaging, photodynamic therapy, and frequency up-conversion lasing. In the first part of my PhD work, synthesis of a series of rigidified ladder-type oligo(p-phenylene)s end-functionalized by bis(dppe)-ligated ruthenium alkynyl units. Their optical, electrochemical and spectra electrochemical properties are discussed. Comparison of these results with non-rigidified ruthenium complexes allows for the determination of the effects of rigidification for promising optical properties. In the second part of this work, a series of rigidified ladder-type oligo(p-phenylene)s end functionalized by nitro acceptor and bis(dppe)-ligated ruthenium unit have been synthesized and characterized. The structure-property relationship of these complexes has been studied.
Embargo
How are multinational corporations operating in Australia reacting to greater tax transparency?
(2024) Van Der Walt, Nicolaas
Abstract Outrage at egregious corporate tax planning practices has seen the introduction of greater tax transparency as a regulatory tool to counteract the systemic under-taxation of multinational corporations (MNCs). Qualitative research undertaken as part of this thesis found that wider access to corporate tax information induces some degree of openness about tax practices among MNCs, but not always to the extent intended. Transparency begets transparency within limits. The limitations are imposed by regulation that does not trigger an automatic change of mindset in MNCs, but rather signals an illusion of regulatory control that needs to be factored into ongoing business modelling. Differences among MNCs in how they make sense of this regulatory control suggest that over time, further inroads into disclosure practices may be achieved with a judicious set of regulatory tools that include further ratcheting up transparency requirements. This research uses legitimacy theory to argue that MNCs' voluntary tax-related disclosures are largely driven by extrinsic motivation and a desire to maintain, or repair, corporate legitimacy - with only a minority of MNCs adopting tax transparency as a corporate value/principle. It appears, for most MNCs, that transparency moves their hands but not their hearts. This instrumentalist approach means that MNCs operating in Australia overwhelmingly self-legitimate aggressive tax planning based on pure 'legality', allowing them to skirt morality considerations and to resist demands to pay a 'fair share' of tax. MNCs are cognisant, however, that civil society actors perceive overly aggressive tax structuring as a breach of corporations' social contract obligations, causing an erosion of offending corporations' moral legitimacy. To protect their corporate reputations and to safeguard social licences, MNCs consequently 'contextualise' information releases relating to their tax behaviour. The desire to remain in control of their disclosure environments creates the risk that MNCs might be investing in appearances and engaging in mock compliance, instead of undertaking fundamental reform. In this thesis, Erving Goffman's theatrical metaphor of 'frontstage' versus 'backstage' behaviour is used to devise a typology of MNCs operating in Australia. In this regard, the research compares the behavioural impact of transparency on MNCs' public reporting with key interviewees' private observations behind closed doors. By analysing these data in terms of the degree to which an MNC institutionalises tax transparency and/or shuns tax aggressiveness, a particular MNC can be categorised as either 'hardcore', 'poser', 'incremental change', or 'restructured'. The research found that greater tax transparency indeed had some 'chilling effect' on corporate tax aggressiveness, even though - as a stand-alone mechanism - it fell short of being a behavioural game-changer. Based on the AMP framework of 'awareness' (A), 'motivation' (M), and 'pathways' (P), this thesis advocates for greater and broader tax transparency, increasing motivational pressure through wider access to MNCs' country-by-country reporting data and the building of credible pathways toward fundamental international tax architecture reform. Furthermore, to augment regulatory capacity within the tax ecosystem, non-state actors - whose tax-technical proficiency is in the process of developing significantly - should be empowered to access and analyse MNCs' tax-related information as uncovered through tax transparency measures.
Embargo
Durability of High-temperature Absorber Coatings
(2024) Hosseini, Sahar
Solar absorber coatings play a crucial role in concentrating solar power (CSP) plants by converting solar irradiance into thermal energy. The primary objective of the research presented in this doctoral thesis is to understand the optical and physical degradation mechanisms for such coatings while in operation. Such knowledge will assist future development of new coatings, with better durability and improved optical performance. This study focuses on three coatings: (1) Pyromark 2500, a coating in common use; (2) a so-called 'coral-structured coating' developed by industry partner Nano Frontier Technology (NFT); and (3) CoteRill750, a coating developed by John Cockerill. Aging mechanisms were studied for all three coatings using different accelerated aging tests. Isothermal aging tests at 800C and 900C showed that optical degradation of these coatings is primarily associated with changes in morphology and the formation of new phases. Analysis of coatings that failed mechanically during testing suggests key reasons for such failures include reduction in bonding strength owing to micro-defects and the formation of oxide layers, combined with stress caused by thermal expansion coefficient mismatch between layers. The coral-structured coating was found to be more resistant to thermal stress compared to Pyromark because of the macro- and micro-porous structures, which accommodate thermal stresses. For Pyromark, curing temperature was found to be an important factor in optical and mechanical stability. Isothermal aging testing cannot simulate conditions on a cloudy day, where coating temperatures may fluctuate significantly. Therefore, thermal cycling tests under a range of different conditions were conducted. The results showed that the combination of temperature ramping plus holding at high temperature accelerated aging mechanisms. Such mechanisms include diffusion, sintering and growth of oxide layers, which all contribute to optical degradation and reduction in the bonding strength between layers. Hence, this type of test is necessary for comparing the durability between different coatings. Further testing focussed on thermal cycling using on-sun and high-flux facilities, albeit for a shorter time. Another topic examined in this doctoral research is the measurement of coating emittance, which is a factor affecting emission loss from the receiver and efficiency at high temperatures.

Browse

Recent Submissions