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  • (2020) Portocalis-Van Toorn, Christine
    Thesis
    It has been argued that the current business environment is so dynamic and techno-centric that Chief Information Officers (CIOs) must be transformational leaders capable of providing the strategic vision expected of other C-Suite members. This requires CIOs to have the ability to drive change, generate business value and leverage innovative technologies for competitive advantage. As a result, many CIOs see themselves as nomads, with their role loosely defined by a technology-determined past but bound by a strategic business-focused future. Despite the changing organisational expectations of CIOs, there has been little research on the role of a CIO over the past 10 years and there is a paucity of research on the competencies required by CIOs. This study explores the changing roles and responsibilities of CIOs and identifies the competencies required to fulfil these changing roles and responsibilities. The study is based on over 30 hours of in-depth interviews with 30 CIOs in leading organisations across six industry sectors in Australia. Data analysis consisted of a four-stage process that first identified required competencies before linking these to the roles that CIOs must undertake in order to meet organisational expectations. Analysis revealed that all CIOs require a core set of Social & Behavioural, Cognitive and Functional competencies in order to fulfil their role as a C-Suite member. In addition, the CIO undertakes one or more of five specialised roles depending on the needs of the organisation. These specialised roles are as Catalyst of Change, Leader, Visionary, Architect, and as ‘Chameleon’, who can seamlessly collaborate with and connect a wide variety of internal and external stakeholders. The analysis reveals the additional competencies, beyond the core competencies, required to fulfil each of these roles. This study is the first piece of research in the CIO space to be true to the concept of competency as utilised in other fields. It provides a significant updating to our understanding of the roles and responsibilities of the CIO and argues for a re-conceptualisation of the CIO as a function rather than an individual. It concludes by presenting a CIO competency Model.

  • (2020) Vats, Gaurav
    Thesis
    This thesis compiles the applications and nanoscale understanding of electrical, optical and mechanical manipulation of ferroelectric domains in ((K0.5Na0.5)NbO3–2 mol% Ba(Ni0.5Nb0.5)O3−δ) (KNBNNO). KNBNNO is a novel bandgap (1.6 eV) engineered ferroelectric with an excellent piezo-response (100 pm/V). This made it interesting for light-dependent nanoscale investigations using scanning probe microscopy. The light is found to work analogous to an applied electric field and the charge carriers generated by the presence of light are found to be compensated by the movement of ferroelectric domains. The domain wall velocities achieved by the exposure to the light source are of the order of 0.01 nm/s. To make KNBNNO viable for practical applications, the domain wall velocities were further enhanced to 30,000 nm/s by the cumulative effect of light and low electric fields (< 4 kV/mm). The light illumination on this material is found to tune the material’s electrical conductivity by orders of magnitude and the charge injection due to illumination is governed by the ferroelectric photovoltaic effect. KNBNNO is also found to illustrate mechanical switching under atomic-force microscopy (AFM) tip pressure (> 0.4 μN). It is found that tip pressures higher than 3 μN can cause permanent deformation of the sample surface. The optical response of the materials is found to be influenced under the mechanical loading via an atomic force microscope tip. The presence of multiple domain switching mechanisms in KNBNNO makes it interesting for an ample spectrum of applications (neuromorphic computing and solid-state energy conversion) and to develop a fundamental understanding of more complex possible mechanisms. Based on the understanding gained, the phenomenon of electro-optic control of ferroelectric domains is utilized to modulate photo- and pyro-currents. Using this, a prototype monolithic light-effect transistor is presented. This could be a potential solution to the scaling limit of three-terminal transistors. In addition, two novel energy conversion cycles (Opto-electric and thermo-opto-electric) are proposed. Finally, the study is concluded with a hope to motivate the scientific community for utilizing the cumulative effect of light, electric field and mechanical force for novel devices and applications.

  • (2021) Myekhlai, Munkhshur
    Thesis
    The electrochemical water splitting reaction, which consists of hydrogen reduction at the cathode and oxygen evolution (OER) at the anode, is one of the core processes for the utilization of sustainable and green energy sources. However, the sluggish kinetics of the oxygen evolution reaction requires a higher overpotential than the theoretical potential (1.23 V). Engineering a high-performance electrocatalyst is an avenue to improve the reaction kinetics for OER. Bimetallic branched nanoparticles offer substantial benefits for OER electrocatalysts; which include a greatly increased exposed surface area, highly crystalline hcp branches and stable surfaces. This thesis aims to design branched nanoparticles as electrocatalysts for enhanced OER in the following ways: (i) extending the cubic-core hexagonal-branch growth approach for a new bimetallic (Co, Au) system, (ii) leveraging the advantages of the Ru-Pd branched nanoparticles by tuning the surface facets and branch number, and (iii) making branched nanoparticles consisting of a cubic core (Pd) and alloyed branches (RuCo). Chapter one discusses the literature on the oxygen evolution reaction and Co- and Ru-based electrocatalysts for OER as well as the organic solution-phase synthesis method. The limiting factors of Co- and Ru- based catalysts and the strategies for improving their catalytic performance are also summarized. Also outlined is the fundamental understanding for synthesizing metallic nanoparticles using a seed-mediated growth approach in an organic solution phase and controlling the shape and size of the final products. Chapter two describes the synthetic methodology, sample purification, ink preparation for electrochemical measurements and characterization techniques in more detail. Chapter three provides the synthetic approaches and challenges in making Co and Ru branched nanoparticles. Chapter four compares the OER catalytic activity and stability of the Co-Au branched nanoparticles with the Co-Au core-shell and Co3O4 nanoparticles in alkaline media. The improved catalytic performance of the branched nanoparticles can be attributed to the formation of an active and stable oxide layer on the branch surface. Chapter five investigates the effect of branch number, and surface facets on the catalytic properties of the Ru-Pd branched nanoparticles with tunable branch number and surface facets. It is found that tuning surface facets and branch length is essential for enhancing catalytic performance by increasing the exposure of more active sites and improving the accessibility of the catalytic surface to the catalytic reaction. Chapter six explores alloyed branched nanoparticles consisting of a Pd core and RuCo branches and assesses their catalytic activity for OER electrocatalysts. It is demonstrated that Co leaching during catalytic activation in acid solution increases the exposure of highly catalytically active sites on the branch surface resulting in enhanced catalytic activity. Chapter seven concludes the overall results and achievements of this thesis and also discusses future opportunities.

  • (2021) Djuandhi, Lisa
    Thesis
    With a theoretical capacity of 1672 mA h g-1, more than five times higher than any commercially available lithium-ion (Li-ion) cell systems, the lithium-sulfur (Li-S) cell is an attractive candidate for next generation energy storage. Despite this high theoretical capacity, Li-S cells generally suffer from poor capacity retention and working lifetimes that prevent them from mass commercialisation. This is mainly due to current limitations in managing the inherent Li-S redox reactions which involve diffusion and migration of electrochemically active polysulfides. One approach to prevent polysulfide migration is by rational design of the sulfur electrode framework. The aim of this research is to investigate the electrochemical implications of using different frameworks for entrapment of redox active species, mainly designed for the Li-S cell system. The two types of frameworks investigated are: (1) mixed-morphology carbon feeds derived from waste sources wherein the intention is for the carbon to purely act as a structural framework to trap lithium polysulfides, and (2) sulfur-rich copolymers wherein redox active sulfur is covalently bound within the framework. More specifically, the goals involve determining: (1) whether carbon acts purely as a structural framework to trap redox active species during electrochemistry, and (2) whether sulfur-rich copolymers act purely as a sulfur feed. Achieving these goals requires a thorough understanding of what properties in each framework are ideal for the Li-S cell. The main conclusion drawn from this work is that neither of the materials studied behaved as pure structural or covalent frameworks partaking in various side processes. Using specialised techniques such as X-ray powder diffraction, solid-state NMR, and X-ray absorption near-edge structure spectroscopy, the beneficial and parasitic side processes involved in each framework are able to be determined. Overall, a significantly enhanced understanding of the Li S cell chemistry when using these materials is presented in this work.

  • (2021) Rathbone, Harry
    Thesis
    Photosynthesis has played a key role in the evolutionary trajectory of life on Earth. The ways in which organisms harvest sunlight have diversified over the billions of years since photosynthesis emerged in the quest for more efficient use of this energy source. The evolutionary origins of some organisms’ light harvesting apparatus, however, have remained elusive as have the causes for stark architectural changes between evolutionarily related organisms. In this thesis, I firstly provide a detailed exploration of published data describing photosynthetic efficiency through the lens of structural biology and quantum mechanics, examining observations from a range of antenna systems. After having built a framework for how an efficient photosynthetic antenna may be constructed, the rest of this thesis explores the evolutionary trajectory of the light harvesting antenna of the cryptophyte algae. Cryptophytes are a clade of secondary endosymbiotic algae which gained their photosynthetic chloroplasts from an engulfed red alga, but produced in an architecturally distinct antenna. Red algae have an antenna comprised of stacked protein rings that form an energetic funnel to the photosynthetic reaction centre which generates chemical energy from photon excitations. Cryptophytes took this energy funnel and dismantled it; complexing one of its component proteins with a peptide of unknown origin (‘cryptophyte alpha’) and packing them at high density within the chloroplast. By examining recently published cryo-electron microscopy maps of red algal antennas, I have discovered the evolutionary ancestor of the unique cryptophyte alpha subunit. Through this discovery, I reveal possible evolutionary events following secondary endosymbiosis leading to the origin of the cryptophyte light harvesting system. Finally, I examine the light harvesting antenna of a particular cryptophyte species, Hemiselmis andersenii, isolating multiple protein components and determining their crystal structures at high resolution. Through this, I discover a more complex antenna than previously thought with multiple protein components and a rich energetic structure. Some of these antenna proteins show previously unrecognised spectral properties and chromophore architecture. This structural data aids in understanding the architectural change between the red algal and cryptophyte light harvesting antennas and further diversification within the cryptophyte clade.

  • (2021) Webb, David
    Thesis
    Planetary waves play a role in a large variety of oceanic and climate dynamics. In particular, Kelvin waves can provide rapid teleconnections from large-scale climate and weather events to remote regions of the globe. Kelvin waves may be partially responsible for linking climatic changes in Southern Ocean winds to increases in subsurface warming around Antarctica that can lead to glacial ice-melt and increases in global sea level rise. Kelvin waves may also link changes in Southern Ocean winds to increases in North Atlantic Deep Water (NADW) formation and an enhancement of the Atlantic Meridional Overturning Circulation (AMOC), which is responsible for circulating a vast amount of the ocean’s heat and nutrient content. However, the exact role of Kelvin waves in these processes is unclear. This thesis aims to further clarify the role that Kelvin waves play in these high-latitude climate processes. First, we use a suite of idealized models in order to better understand the dynamics of barotropic Kelvin waves around Antarctica. We find that super-inertial (high frequency) barotropic Kelvin waves are nearly completely scattered away from the Antarctic coastline due to a combination of coastal geometry and bathymetry. Sub-inertial (low frequency) barotropic Kelvin waves are mostly scattered away from the Antarctic coastline due to bathymetry, however a significant amount of barotropic Kelvin wave energy remains at the Antarctic coastline after one circumnavigation of the continent, enabling a gradual build-up of energy along the coast and the ability to sustain a barotropic Kelvin wave signal around Antarctica over time. Secondly, we perform a diagnostic study using theory and a range of varying resolution model simulations to quantify the amount of subsurface warming along the West Antarctic Peninsula caused by barotropic Kelvin waves via an induced bottom Ekman flow that advects warm Circumpolar Deep Water onto the Antarctic continental shelf. We find that barotropic Kelvin waves can account for a substantial amount of warming within one year, depending on the background temperature gradients and thickness of the bottom Ekman layer. Lastly, we explore the role of Kelvin waves in linking Southern Ocean wind-stress to NADW formation and the AMOC by analysing ensemble simulations from a fully-coupled ocean-sea-ice model at 1/4 degree horizontal resolution (50 vertical levels). We find first mode baroclinic Kelvin waves to propagate along a global coastal and equatorial waveguide from the Southern Ocean forcing region to the North Atlantic, where downwelling waves initiate an enhancement of the AMOC by making surface waters denser.

  • (2021) Cai, Lin
    Thesis
    This thesis consists of three chapters that investigate the linkage between uncertainty and corporate investment decisions on an international basis. In first chapter, I investigate the extent of U.S. policy-related spillovers into 22 other real economies. I find that, after accounting for factors previously used to explain corporate investment, US Economic Policy Uncertainty (US EPU, hereafter) fluctuations affect foreign corporate investments through two channels. First, the single effect of US EPU on international corporate investment shows an unequivocal negative relation (the direct channel). Second, an increase in US EPU also attenuates the negative sensitivity of corporate investment towards the cost of capital (the indirect channel). Further, I find that while the direct channel of US EPU on corporate investment persists across several subsamples, its indirect channel relates to a high degree of dependence on the U.S. economy and opacity exhibited by local economies. The second chapter reconciles the contrary views on the foreign investors using local disaster shocks from 46 countries over the period 1998-2018. I find that local disaster shocks cause significant disruptions to corporate investments, but foreign institutional investors attenuate the costs of disaster risks. The benefits associated with foreign institutional investors are not uniformly held across all economies, where the role of foreign institutional investors is particularly measurable in countries with well-developed institutional environment. The third chapter focuses on the uncertainty at domestic level using national elections across 23 different countries. I find that the corporate investment cycle corresponds with the timing of national elections, but there is a cross-sectional difference in the firm-level investment sensitivity to elections. During election periods, while firms temporarily reduce investment expenditures relative to nonelection years, the decline is mainly sourced from firms with greater political exposures. Further, I find that the investment cycles are more volatile when the election outcomes are uncertain, and the institutional environments are weaker.

  • (2020) Chua, Ngee Kiat
    Thesis
    Cholesterol is an essential lipid associated with many important biological functions. At both the cellular and physiological levels, cholesterol is acquired through two main sources. One source is uptake, while the other source is de novo cholesterol synthesis. Squalene monooxygenase (SM) is a rate-limiting enzyme of cholesterol synthesis. A few studies have suggested SM could be a promising treatment target to lower cholesterol levels in the blood and as another metabolic target in certain cancers. Thus, there is an increasing need to understand the regulation of this enzyme. One critical mode of regulation is the cholesterol-accelerated degradation of SM. This process requires the first 100 amino acids of SM (termed SM N100). The SM N100 regulatory domain represents a degron region (a degradation signal), which allows SM to be regulated by cholesterol. However, insights into cholesterol sensing by SM N100 and the mechanisms by which SM N100 confers instability were unknown. To investigate this degron, we utilised SM N100 fused to green fluorescent protein, a fusion protein which recapitulates the cholesterol-accelerated degradation of SM. Here, we have performed a series of point mutations, truncations and domain swaps based on our understanding of known degron features. We identified that an amphipathic helix (residues Gln62–Leu73) in SM N100 is required for cholesterol-accelerated degradation. We also present evidence that the cholesterol-driven disorder of the amphipathic helix lengthens the disordered region surrounding the helix and exposes a hydrophobic patch which accelerates SM N100 degradation. Attempts to identify ubiquitination sites revealed SM N100 undergoes non-canonical ubiquitination at serine residues to signal SM N100 for degradation. Finally, we identified valosin-containing protein (VCP) as a key protein which mediates the removal of the SM N100 degron from the endoplasmic reticulum into the cytosol for degradation. In summary, we have increased our understanding of the SM N100 degron architecture, furthering insights into how cholesterol sensing in the endoplasmic reticulum is coupled to protein quality control.

  • (2022) Hush, Anna
    Thesis
    For decades, feminists at Australian universities have fought to publicise and politicise the issue of campus sexual violence. These efforts have recently come to fruition, with universities publicly acknowledging the problem and undertaking various institutional reforms. However, there has been little scholarly attention paid to political struggles over sexual violence within universities. This thesis critically examines the politics of feminist activism against sexual violence at Australian university campuses. It situates this activism against the backdrop of the neoliberalisation of Australian universities, to reveal how feminists have challenged – and at times, acted in complicity with – these transformations in the landscape of Australian higher education. This analysis is both historical, drawing on archival material relating to the history of campus feminist politics, and contemporary, using data from interviews with students currently engaged in organising against sexual violence. It explores the strategies and tactics adopted by feminist collectives, the constraints on feminist mobilisation in the neoliberal university, and the shortcomings of these movements. This thesis makes two original contributions to knowledge. Firstly, it extends existing analyses of university sexual violence and contributes to the growing body of scholarship on this topic. Research on campus sexual violence in Australia has so far focused on policy analysis and prevalence data. While this provides an important basis for evaluating the scope of the problem and potential remedies, it is largely disconnected from political struggles over institutional responses to sexual violence, a gap this thesis seeks to fill. I offer an analysis of the historical and contemporary struggles that have created the conditions for institutional change, as well as the complex ways in which the neoliberal university undermines and constrains oppositional movements. Secondly, this thesis makes a theoretical contribution to the field of New and Feminist Institutionalism. It critically intervenes in the institutionalist field, drawing greater attention to the roles of macro-social contexts and actors in the form of social movements in processes of institutional change and proposing a framework that foregrounds these aspects of institutional politics. The findings of this research reveal significant limitations in Australian universities’ responses to sexual violence, with their actions falling short of both student demands and expert recommendations. I argue that these actions have largely functioned to consolidate managerial power and mitigate reputational risk, in doing so narrowing the space of political contestation. My analysis further illuminates the specific institutional constraints that bear upon student feminist organisers within the neoliberal university. This analysis offers strategic insights into feminist engagement with institutions, suggesting that student movements must develop the capacity to disrupt processes of institutional reproduction and challenge the reformist approach adopted by universities. A transformative response to campus sexual violence, I argue, will require broader and better-organised coalitions of staff and students in order to collectively challenge and overcome these constraints.

  • (2020) Khan, Mahjabeen
    Thesis
    Pseudomonas aeruginosa causes both contact lens and non-contact lens-related keratitis (corneal infection). This opportunistic bacterium naturally has the ability to resist the mechanism of action of many antibiotics which are used for treatment. P. aeruginosa resistance patterns and the mechanism of resistance in isolates from keratitis are not well understood. This thesis described the phenotypic and genotypic patterns of antimicrobial resistance and compared these between ocular isolates of P. aeruginosa from Australia (contact lens) and India (non-contact lens). Changes in the antimicrobial susceptibility between isolates over time were also analysed. Susceptibility to antibiotics, multipurpose disinfecting solutions and disinfectants was analysed for twenty-seven Australian isolates from contact lens-related keratitis and forty non-contact lens-related isolated from India. The whole genomes of fourteen Australian (historical and recent) and twelve Indian isolates were sequenced using Illumina® MiSeq®. Computational analysis of the genomes was performed to analyse their core and pan genomes and these were examined for the presence of acquired resistance genes, virulence genes, gene mutations, and these compared to their phenotypic resistance to antibiotics. Indian isolates possessed large pan genomes with more acquired resistance (30) genes and larger numbers of genetic variations. The Indian isolates contained clones of three sequence types ST308, ST316 and ST491, whereas Australian isolates contained only one sequence type ST233. Isolates with larger gene variations had mutations in the DNA mismatch repair system. Most multi-drug resistant Indian (non-contact lens) isolates were exoU +. Indian isolates had large accessory genes compared to Australian isolates and this increased the pan genome size of the Indian isolates. The number of core genome mutations were larger in the Indian isolates a median of 50006 (IQR=26967-50600) compared to Australian isolates a median of 26317 (IQR=25681-33780). There were differences between isolates from Australia and India with respect to their antibiotic resistance and associated genes. Indian strains had more genetic diversity and were multi-drug resistant. However, there was no evidence of substantial genetic or phenotypic changes within isolates from their respective countries.