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(Upcoming) The Interplay of Formal and Informal Social Protection in the Global South
No full textPeer-reviewe
Managing rangeland change in New South Wales for landscape repair
No full textThe rangelands of southeastern Australia are a landscape with extensive evidence of historical land degradation. Monitoring and managing this historic land degradation is made challenging by the disparities of scale throughout the rangelands, which make implementing solutions to ongoing erosion difficult. Monitoring wind erosion is one metric that has been used as a proxy for landscape condition, with the focus on direct measurement of dust emissions. However, in the past decade there has been a pivot towards using remote sensing products to monitor groundcover as a proxy for dust, allowing more flexible and adaptive monitoring regimes.
This in turn creates an opportunity to extend these remote sensing products to monitoring at paddock-scales, thereby informing timely land management decision-making. The approach in this thesis is to explore the evolution of techniques used to inform land management decision-making with a specific lens of wind erosion. This is achieved through a case-study approach, using a series of locations throughout rangeland New South Wales to explore land degradation with a historical perspective. Through these case-studies, the transition from measuring and monitoring dust, to the adoption of using remote sensed groundcover products that provide paddock-scale information relevant to land managers is examined.
To do this, this thesis first considers the historical context of erosion in the rangelands of southeastern Australia, and puts this into the context of changing management options. This is supported by comparing DustWatch data against local social metrics, and using a more targeted dust metric for comparison against regional Landsat groundcover and ABARES land use data. While these regional dust analyses produce interesting results about regional dust, they don't successfully localise and geolocate dust emission sources. Therefore, MODIS and Landsat groundcover is used to build a novel cumulative metric of landscape condition, with this cumulative cover product offering a novel way to view and examine fractional cover data. Two common landscape repair treatments (waterponds and wagon wheels) are examined with this cumulative metric to assess the impact of land management interventions.
This is then extended through three case-studies focussed on the use of water as a mechanism through which land managers can monitor landscape repair, two focussed on LFA and one on piospheres. This is then supported by an examination of whether landscape repair can be rebuilt by alternative applications of remote sensing. To this end, an index of landscape functionality gain is developed from Landsat fractional cover to extend cumulative cover, using a self-referential control at Bokhara Plains, and connected to land management inflexion points.
The results of this thesis are significant, as they indicate that it is potentially possible for land managers to conduct their own remotely sensed paddock-scale monitoring using publicly available datasets. This thesis critically develops alternative ways to view and analyse groundcover data in order to build understanding of trends and patterns within properties. This is valuable, as it empowers the land manager to understand the link between their management decisions and groundcover dynamics- a key element that underpins grazing production and protection from land degradation. Empowering land managers with this knowledge accelerates the capacity to build landscape function and effect landscape repair. This offers land managers opportunities to access emerging natural capital markets, and may have major implications with future policy changes. Through this, further development of the remote sensing capabilities examined in this thesis has major potential to support New South Wales rangeland managers in repairing degraded landscapes and address the legacy of accelerated erosion in rangeland southeastern Australia
High-Dimensional Inference under Dynamics and Complexity: Applications in Biology and Finance
No full textThis thesis focuses on advancing statistical inference methods and theoretical understanding for modeling and optimization problems in high-dimensional settings, specifically targeting scenarios where the number of variables substantially exceeds available observations. The central contributions include the development of a robust method for detecting change points in graphical models and an in-depth theoretical analysis of the "double descent" phenomenon in mean-variance portfolio optimization.
In Chapter 2, we propose the Factor-Augmented Graphical Model (FAGM), a novel methodology for detecting structural changes in piecewise-constant graphical models. Unlike traditional approaches that assume independent observations and static network structures, FAGM explicitly incorporates unobserved, temporally correlated common factors. This allows the method to isolate true shifts in conditional dependencies by analyzing error components, which are assumed to be independently and piecewise-identically distributed. We rigorously establish the theoretical consistency of a regularized estimator and demonstrate its effectiveness through extensive simulation studies and a real-world application involving gene expression data.
Chapter 3 investigates the empirically observed but theoretically ambiguous "double descent" phenomenon within the framework of mean-variance portfolio optimization. By explicitly modeling complexity through the number of assets, we uncover a distinctive "double ascent" pattern in the out-of-sample Sharpe ratio. Initially, increased portfolio complexity enhances performance, followed by deterioration due to estimation errors, and eventually a renewed improvement when complexity surpasses the number of observations. Our theoretical results provide transparency into the causal mechanisms behind this phenomenon, quantifying how economic benefits (theoretical Sharpe ratio) and statistical accuracy (estimation precision) jointly drive this counterintuitive behavior. This analysis reveals that over-parameterization can significantly outperform simpler models in high-dimensional portfolio selection contexts.
Collectively, this thesis provides rigorous theoretical foundations, complemented by extensive simulation and empirical studies, clearly demonstrating the practical utility and robustness of the proposed statistical methodologies and theoretical insights
The nutritional ecology of the Zanzibar red colobus (Piliocolobus kirkii) within modified habitats
No full textAs primate habitats are being continually altered by human activity, animals need to adapt in various ways in order to survive. This is particularly true for folivorous primates as modified landscapes usually results in directly affecting their food resources. With disturbed habitats comes an increased number of introduced plant species. These exotic plants most often contain unfamiliar secondary compounds that can be potentially harmful when ingested. There is currently little work that investigates how living in a modified environment impacts the dietary ecology of folivores, which is vital when implementing conservation strategies to ensure their survival. This study focuses on four groups of endangered Zanzibar red colobus monkeys (Piliocolobus kirkii) that live in a variety of anthropogenically modified habitats in the Jozani Chwaka-Bay National Park & Biosphere Reserve, Zanzibar. One group resided in the southern part of the National Park, utilising heavily disturbed regenerated edge forest and the surround shambas (farmlands). Three other groups deeper in the forest were also followed, whose habitat disturbance levels ranged from low to moderate. Within these environments, some groups have adopted the unusual behaviour of consuming charcoal, which is thought to serve as a detoxification agent by adsorbing harmful phenolic compounds found in many of these introduced plant species. By comparing data on different habitats, behaviours, diets and the chemical constituents of food plants, a better understanding of how these folivores have adapted to cope with modified environments, will be gained. Results indicate that habitats, behaviours, diets and feeding strategies have changed since research was conducted in the area by Mturi (1991) and Siex (2003). Overall, the shamba group had a larger home range, a broader dietary diversity containing more exotic plant species and consumed charcoal most frequently, compared to the forest groups. Nutritional analysis of samples from each groups diet, indicated that the ZRC food items differed greatly in levels of important constituents; with the overall nutritional profile of samples from one group being higher in protein, while that of the other groups excelled in energy, minerals or was relatively balanced. Habitat disturbance levels did not coincide with the nutritional fingerprints of the samples analysed. This study elucidates how the ZRC are using their habitats when exposed to modified habitats along with how better conservation strategies can be implemented to benefit this endemic species
Couette Flow Linear Dichroism Spectroscopy
No full textLinear Dichroism (LD) spectroscopy uses linearly polarized light to measure how a molecule orients itself with respect to a reference axis or, more precisely, how the transition moment of a chromophore in the molecule is oriented. This provides insight into how, e.g., molecules assemble into macromolecules and their orientation with respect to each other. Prerequisites for LD is a medium in which the molecules orient in a preferred direction and that the molecules under investigation are long enough to allow orientation. For long biomolecules such as RNA/DNA or fibrils of proteins in solution, Couette flow is an efficient way of creating a flow-induced orientation of the molecules, while recirculating a small volume of sample. In this chapter, we present the methodology behind LD spectroscopy including best practice for sample handling and data collection, as well as the interpretation of LD spectra including examples of RNA, DNA, proteins, and their complexes.Peer-reviewe
The effects of thermal history and composition on the thermodynamic behaviour of helium in tungsten and tungsten-based alloys
No full textNuclear fusion power is the promise of clean energy generation to meet the demands of the new century. However, containing a plasma with a core temperature ten times hotter than that of the sun is no easy task. The confinement vessel must be constructed from resilient materials that can withstand both the heat and the bombardment of the plasma species. ITER is the first proof-of-concept reactor in constructed. This thesis aims to assist in ITER's goals of understanding the complex fundamental plasma-material interactions and developing materials resilient to the harsh reactor conditions in the global push for nuclear fusion energy.
The first goal of the thesis aims to investigate the thermodynamic properties of helium (He) bubbles to contribute to the existing understanding and models of He PMI expected in ITER. Bulk W samples were exposed to a low-energy (25 eV) He plasma at 573 K (LT) and 1050 K (HT). After plasma exposure, these samples were subject to TDS, ERDA, SEM, and in-situ TEM annealing. Structures comprised of a network of bubbles were stable up to 998 K during in-situ TEM annealing of the LT sample. He desorption from the LT sample was inferred to stem from interstitial He rather than these bubbles. Bubbles in the HT sample were found to be thermally active up to 998 K, resulting in an increase in the average bubble size and a loss of number density. GISAXS analysis on the effects of annealing on bubble radius distribution produces results consistent with the TEM. An "Ostwald ripening-like" model was proposed to explain the differences in annealing behaviours of the LT and HT samples. In-situ TEM annealing of a HT bulk W sample at 1073 K showed a reconfiguration of lattice atoms to reduce the surface area of large voids left behind after plasma exposure. It is suggested that lattice effects also contribute to the formation of fuzz and require more investigation.
The results provided a deeper understanding of the bubble formation mechanism and subsequent thermodynamics based on the plasma exposure temperature. The differences in behaviour observed from these experiments can be used to help explain temperature-dependent effects such as recrystallisation suppression and form a wide set of consistent experiments for computational models to be compared to.
The second goal of the thesis is to characterise the He-PMI of three alloys for possible use as a divertor material in future fusion reactors.
Four sputter-deposited materials: sputtered pure W (WS), W-5%(wt)Ta, W-3%(wt)Cr, and W-5%(wt)Ta-3%(wt)Cr were exposed to 25 eV He plasma at LT and HT. After plasma exposure, these materials were subject to TDS, ERDA, SEM and TEM. The addition of Ta to Ws and WCr has been shown to inhibit the formation of He bubbles. This may be a case of increasing the fluence threshold for fuzz rather than the complete prevention of fuzz. Additionally, the addition of Ta slows grain growth of both Ws and WCr. This property is intrinsic to Ta rather than from an emergent W-Ta interaction and could potentially be used to delay the undesired but inevitable onset of recrystallisation.
The electrical resistivities of the four sputtered films were measured as a surrogate for its thermal conductivity to characterise how this property changes with alloying and He exposure. The alloying of Ta significantly increases the resistivity of W, much more than that of Cr. As expected, He plasma exposure degrades the resistivity regardless of the material. WTaCr has the largest electrical resistivity and suffers the largest increase after He plasma exposure likely due to the presence of both alloying impurities deforming the lattice and serving as trapping sites. Both effects increase probability of electron scattering. The reduction in thermal conductivity from both alloying and He plasma irradiation, especially for alloys with more elements, will have to be considered alongside its other benefits when determining its viability for fusion reactors
Resistivity distribution and donor properties of antimony-doped n-type Czochralski silicon ingots
No full textWe investigate antimony (Sb)-doped Czochralski-grown silicon as an alternative n-type substrate for photovoltaic applications, and characterize their axial resistivity distribution, donor properties, and mechanical strength. We find that Sb-doped ingots can achieve a more uniform resistivity distribution along the axial direction compared to P-doped counterparts. Dopant concentration profiles in P-doped ingots can be accurately modelled using the standard Scheil's equation, accounting only for dopant segregation during solidification. In contrast, modelling Sb-doped ingots requires consideration of both dopant segregation and evaporation effects to fit the dopant distribution accurately. Using electron paramagnetic resonance spectroscopy at 9 K, we observe two hyperfine lines in P-doped samples, and six hyperfine lines for Sb121 and eight for Sb123 isotopes, with the number of hyperfine lines governed by the nuclear spins. We further identify two-atom Sb clustering in the Sb-doped wafers, confirmed through simulations of the additional weak electron paramagnetic resonance peaks. Finally, we find that 140 μm as-cut planar Sb-doped wafers exhibit slightly higher mechanical strength compared to P-doped wafers.Funding provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Office under Agreement Number 38526.Peer-reviewe
Legacies of Conflict in the Pacific: Why the Past Matters Now
No full textIn July 2025, Conciliation Resources published a report titled Legacies of Conflict in the Pacific: Dealing with the Past, co‑authored by Mercy Masta and Kate Higgins, with contributions from peacebuilding practitioners across Fiji, Papua New Guinea (PNG), Solomon Islands, Bougainville, and other Pacific contexts. Launched at ANU in September 2025, the report emphasises that conflict in the Pacific is not merely historical — its legacies continue to shape the political, social, psychological, and cultural life of communities.
This In Brief examines the lasting impact of past conflict and emphasises the importance of history, memory, and local agency in peacebuilding. Drawing on the compendium, it advocates for inclusive, culturally grounded, and locally led approaches that combine oral and documented histories, support indigenous practices, and prioritise marginalised groups. It also offers practical recommendations for policymakers and peacebuilders to advance long-term reconciliation, justice, and sustainable peace in the Pacific.Australian Department of Foreign Affairs and Trad
