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Faster Attention Disengagement Predicts Social Skills
No full textData file.This file presents the final sample after exclusions were made (as outlined in the manuscript).</p
How Do Aboriginal and Torres Strait Islander Creative Cultural Practitioners in the South East Assert the Multiple Values of Their Culture and Practice to Challenge the Discourse of Indigenous Authenticity Within the Arts and Cultural Ecologies?
No full textAboriginal and Torres Strait Islander art, or creative cultural practices, are valuable to Australia, not just in terms of the contribution to the economy but also for the cultural and social benefits being generated. The arts and cultural ecologies have also featured in policy initiatives to address systemic Indigenous disadvantage. However, the Indigenous art that is lauded both nationally and internationally includes very little of the art produced by Aboriginal and Torres Strait Islanders living and working in the south-east of Australia. The art of the south-east has been characterised in the literature as inauthentic, and this perception of inauthenticity appears to relate to colonial perspectives regarding who should be considered an Aboriginal or Torres Strait Islander person. The purpose of this research is to understand whether there is a discourse of Indigenous authenticity circulating within the Australian arts and cultural ecologies and if so, what its effects are on Aboriginal and Torres Strait Islander creative cultural practitioners in the south-east. Operating at the intersection of the disciplines of Indigenous studies, cultural policy and cultural economics I considered a broad range of literature, and although Indigenous academics and artists, cultural economists and cultural policy theorists have commented on aspects of the arts and cultural ecologies, there has been no comprehensive review of the Aboriginal and Torres Strait Islander engagement with the arts and cultural ecologies through an Aboriginal and Torres Strait Islander lens. Informed by Indigenous standpoint theory and using Indigenous methodologies and grounded theory, I yarned with 20 knowledge holders including creative cultural practitioners producing contemporary Aboriginal and Torres Strait Islander art in south-east Australia, as well as some of their community Elders and art industry allies. Together we considered how they and their communities engage with the established art markets and the broader arts and cultural ecologies. Considering the arts and cultural ecologies from an Aboriginal and Torres Strait Islander perspective gives primacy to the Aboriginal and Torres Strait Islander view of the discourse of Indigenous authenticity circulating within the arts and cultural ecologies and the impact on Aboriginal and Torres Strait Islander creative cultural practitioners and their communities. The study shows that Aboriginal and Torres Strait Islander creative cultural practitioners in the south-east have, since the beginning of colonisation, used their creative cultural practices to maintain and innovate culture and to talk back to the coloniser, and in this way demonstrate Gerald Vizenor’s concept of survivance. The research revealed that whilst racism and the frequently encountered perception that there are no creative cultural practitioners in the south-east remain persistent, there is a vibrant and dedicated community of creative cultural practitioners in the south-east. These practitioners are ensuring that, far from being lost, our creative cultural practices have been nurtured and strengthened. A need for greater education regarding the Aboriginal and Torres Strait Islander population in the south-east and our creative cultural practices within the arts and cultural ecologies, and more broadly, is required to make the community and their practice more visible and recognised. In addition, the knowledge holders identified a need to improve the understanding within the arts and cultural ecologies of the resourcing requirements needed to facilitate the relational engagements involved in Aboriginal and Torres Strait Islander creative cultural practices. In particular, relational practices consistent with a value-based approach emerged as being crucial. For instance, the need to talk with Elders, and to consult with community, may require longer lead times and additional funding to ensure the relational responsibilities which are often at the core of our practice, can be fully honoured. In giving a voice to Aboriginal and Torres Strait Islander knowledge holders, this research shines a light on how creative cultural practice is a crucial element of survivance and creates value that exists beyond the narrow context of the Indigenous art market. While value in purely economic terms, that is, income and financial support for creative cultural practices, was not the key motivation for the practitioners I yarned with, it was clear that their practices were a way to enrich the lives of their community, to honour their Indigenous knowledge and heritage and to revive and reinvigorate their culture.Aboriginal and Torres Strait Islander people should be aware that this thesis and associated project files may contain the images, voices or names of people who have since passed away. </p
Retinal Benefits of Lutein from Gac (Momordica cochinchinensis) Fruit Peel
No full textThe eye is responsible for vision but is vulnerable to decline, injury and disease. At the commencement of this project, there were a few natural products recommended by clinicians as beneficial for eye health (AREDS2, 2014; AREDS2, 2022). This project aimed to investigate the potential of biomaterials capable of improving eye health and managing eye diseases, and it was identified based on in vitro, animal studies and clinical trials that lutein was a major biomaterial capable of promoting eye health particularly age related macular degeneration (AMD) (Chapter 1a). The thesis further examined lutein-rich sources, highlighting a novel and exotic Asian plant source called gac fruit (Momordica cochinchinensis) (Chapter 1b). Advancements and limitations in the extraction and formulation methods of lutein were elucidated (Chapter 1b). The optimisation of lutein extraction from gac fruit were investigated and involved three key parameters: KOH concentration, extraction temperature, and extraction time (Chapter 2). Lutein extracts from gac demonstrated effectiveness in protecting retina pigment epithelium (RPE) cells against H2O2-induced stress (Chapter 3). The lutein was developed as natural nanomaterials that could be clinically used as injectables and topical medicines for improved eye health (Chapter 4). Results from this study contributes to knowledge in natural product assessment and alternative ophthalmic treatments, introduces potential shorter route of administration for lutein in the context of retinal diseases, with the prospect of its application as a healthcare product.</p
Understanding the Role of Gas Diffusion Layer for Pressurised PEM Unitised Regenerative Fuel Cells
No full textIn this PhD thesis, the role of gas diffusion layer (GDL) in pressurised proton exchange membrane (PEM) unitised regenerative fuel cells (URFCs) is investigated. URFCs play a crucial role in the energy transition by efficiently integrating hydrogen production and electricity generation that is important for the applications that space utilisation is of great importance. The research aims to deepen the understanding of the oxygen-side GDL's role in PEM URFC performance, exploring necessary modifications to enhance this performance, particularly in the fuel cell mode of operation. In particular, the study sought to develop methods for estimating the electrical conductivity of metallic GDLs used in PEM URFCs and electrolysers, investigate the impact of GDL hydrophobisation on fuel cell-mode performance, and analyse the role of GDL alongside other parameters in hydrogen crossover in both electrolyser and fuel cell modes.
The research methods implemented in this study included an extensive literature review, theoretical studies, and experimental investigations. The literature review involved critically examining a wide range of existing peer-reviewed research articles, conference proceedings, books, theses, and relevant technical publications. This phase was instrumental in establishing a detailed understanding of the current state of the art in GDL technology and identifying gaps in the field relevant to PEM URFCs. The theoretical aspect of this research utilised established models and approaches, including the rule of mixture, critical porosity, and tortuosity concepts, for estimating the electrical conductivity of sintered metal fibres. Darcy's law was applied for pressure drop estimations across porous media, and Fick’s law of diffusion was used in estimating the hydrogen crossover phenomenon during both fuel cell and electrolyser operation modes. The experimental component was conducted in RMIT University’s Sustainable Hydrogen Energy Laboratory (SHEL) by focusing on the effects of PTFE coating, i.e., as a means for GDL hydrophobisation, on the performance of PEM URFC. These experiments were crucial in translating small-scale single-cell PEM URFC findings to broader applications in larger-scale stacks, ensuring the scalability and practical application of the research. The small-scale PTFE coating of the GDLs was performed in-house and for the large-scale samples, external facilities were utilised. In these studies, the effect of PTFE coating was of interest at the lower temperature range, which has not received the needed attention in the published research.
The research led to the development of innovative semi-empirical models for estimating the electrical conductivity of metallic GDLs, providing a substantial improvement over existing models. These new models particularly offer good accuracy for sintered metal fibres, a material mainly used in PEM URFCs as well as electrolysers due to their favourable properties, especially corrosion resistance. The theoretical models developed for hydrogen crossover in both fuel cell and electrolyser modes offered valuable insights into the complex interplay of operational parameters such as pressure, temperature, current density, and the physical properties of the GDL and catalyst layer, namely thickness and permeability. These models highlighted the critical role of the GDL in influencing hydrogen crossover, a phenomenon essential to the efficiency and safety of URFCs. It was found that GDL compression that affects the GDL permeability can have a marked effect on hydrogen supersaturation, a phenomenon that plays a major role in hydrogen crossover during water electrolysis.
The study revealed experimentally that PTFE coating on GDLs had a considerable impact on fuel cell performance, particularly at lower operating temperatures. While low PTFE loading maintained electrical conductivity and did not have a negative impact on contact resistance, higher loadings resulted in decreased performance due to reduced porosity. These findings underlined the importance of carefully balancing hydrophobic properties depending on the desired operating conditions.
The research effectively addressed critical questions and objectives. Through the comprehensive literature review, the study identified key attributes and modifications of the oxygen-side GDL that impact PEM URFC performance, including porosity, fibre diameter, and hydrophobisation techniques. The newly developed methodologies for estimating GDL bulk electrical conductivity eliminated the need for complex numerical models of GDL, which can be incorporated into numerical studies on PEM URFCs to study the effect of GDL porosity. The experimental investigations into the effects of PTFE coating revealed its significant role in enhancing fuel cell performance under varying operating conditions, providing valuable insights for optimising URFC design based on the desired operating conditions, especially practical operating temperature.
The development of the models for hydrogen crossover enhanced the understanding of this phenomenon and provided the possibility of incorporating hydrogen crossover in 3D numerical models of both fuel cell and electrolyser operations. This enables a more accurate estimation of overall efficiency and the possible effects of hydrogen crossover on durability. Additionally, it assists in determining the safe operational conditions, especially the current density range to ensure hydrogen concentration in oxygen stays within the safe limits. This is a critical aspect of maximising the efficiency of the hydrogen generation and reducing the size of hydrogen production systems utilising water electrolysis, resulting in the reduction of both CAPEX and OPEX.
Future research directions include further exploration into the mechanical properties of metallic GDLs and their behaviour during assembly. Additional experimental studies are required to explore the effects of PTFE coating under diverse operating conditions and hydrogen feed modes. Investigating the microporous layer for the oxygen side of PEM URFCs is crucial to understanding its impact on improving water management and durability. Moreover, considering the substantial impact of contact resistance on ohmic losses in electrochemical devices, investigating the effect of porosity and potentially fibre diameter on contact resistance are recommended. The inclusion of the developed hydrogen crossover models in the numerical modelling of PEM URFCs as well as fuel cells and electrolysers can provide further insight into this phenomenon and support investigating its effect on the durability of the membrane.</p
Essays on Gender Inequality and Health in Bhutan
No full textGender inequality is a great social injustice. Many countries still experience high levels of discrimination between men and women. The issue is particularly pertinent in Bhutan, where there are significant gender inequalities in education, employment, and health.
The first study of this thesis examines the gender wage gap in Bhutan using data for the period 2012 to 2019. This study employs a range of modelling and decomposition approaches to provide deep insights into the gender wage gap. Also examined in this study, is how a change to Bhutan's minimum wage in 2014 impacted the gender wage gap. Results suggest a significant gender wage gap in rural areas compared to urban ones once socio-economic characteristics have been taken into account. The wage gap and discrimination are highest at the lower end of the wage distribution and then decrease gradually when moving up the distribution, thereby depicting a robust sticky floor effect. Also, the study finds that the minimum wage rate policy significantly improved wage income and reduced the gender wage gap at the lower end of the wage distribution. By examining gender differential effects in different sectors and on the minimum wage policy, this study makes an important contribution to the existing literature.
The second study examines the impact of the national-level alcohol and tobacco policies on alcohol, tobacco, and areca nut consumption in Bhutan for the period 2007 to 2022. Using Seemingly Unrelated Regressions and Trivariate Probit models, the economic relationships across drugs are investigated. To this extent, the study uses both drug price and drug control policies to examine how the demand for, say, areca nut responds to changes in areca nut price as well as alcohol and tobacco control policies. This allows the establishment of crucial cross-drug relationships that are extremely useful towards formulating effective drug policies and anti-drug campaigns. This study finds that alcohol and areca nut are sensitive to their own prices. In terms of cross-drug relationships, consumption of both tobacco and areca nut reduces in response to alcohol control policies, indicating they are economic complements for alcohol. Also, the study finds alcohol and areca nut products are economic complements to tobacco; the consumption of both drugs declines in response to tobacco control policies. This study is the first to determine economic relationships across different types of demerit goods in Bhutan.
The third study constructs a mental health index using the World Health Organisation’s Global School-based Student Health Survey data and investigates the determinants of mental health in school-aged adolescents in Bhutan, using advanced techniques such as the Receiver Operating Characteristics and the Lasso regression. The study finds that strong parental and peer support reduce adolescent mental health risks, while negative experiences like injuries and bullying increase them. Adolescent females, particularly those who engage in alcohol abuse, are more likely to have mental health problems. Lifestyle factors such as sedentary behavior and smoking are positively associated with mental health issues. Highlighted in this study is the complex interplay of socio-demographic and lifestyle variables in shaping adolescent mental health outcomes in Bhutan.</p
Designer Solvents for Understanding Protein Stability
No full textProteins have been harnessed for biotechnology applications including but not limited to detergents, pharmaceuticals and biocatalysis. However, many proteins are limited after purification due to their poor long term (shelf life) and thermal stability as well as low solubility in aqueous buffered solutions. This problem can be directly related to the fundamental interactions between proteins and their solvents. Therefore, research into the effect of solvents on protein solubility and stability could shed light on these interactions. A class of non-aqueous solvents showing promise for protein stabilisation is ionic liquids (ILs). ILs are liquids consisting of cations and anions, with tailorable properties due to the structural variation of their ions. Some ILs have been shown to enhance protein solubility, activity and/or stability. However, due to the compounding complexity of IL solvents and protein structure, there is no comprehensive understanding of the influence of ILs on proteins. This necessitates additional, thorough investigation of the many aspects of IL based solvents and protein structure, beginning from a fundamental standpoint of IL structure-property relationships to the specific ion effects of model proteins in IL solvents.
This thesis aims to use the characterization of IL physicochemical and solvation properties to better understand their effect on model proteins. Beginning with the synthesis and characterization of novel ILs, followed by the targeted investigation of protic IL (PIL) structural effects on solvation properties. Finally, it aims to correlate the structure and concentration of ILs with their effect on shape, size, and aggregation of the model proteins hen egg white lysozyme (HEWL) and human lysozyme (HL).
Initially the experimental aim was to expand the known structure-property relationships of ILs. The use of machine learning (ML) algorithms and the comprehensive experimental characterisation of both novel and reported ILs have been conducted to address this knowledge gap. The work presented herein includes the synthesis and characterization of a library of 50 ILs, systematically chosen for their structural variance. This included structural moieties of hydroxyl groups, primary to quaternary ammonium cations, both inorganic and organic anions as well as varying the alkyl chain length on either the cation or the anion. Each IL was extensively characterized for their physicochemical, thermal, and liquid nanostructure properties. Further analysis using ML algorithms enabled the quantification of the influence of these structural moieties on IL properties, as well as the qualitative prediction of thermal properties. ML showed that density, surface tension and refractive index were almost entirely based on IL structure and the powerful influence of the presence of hydroxyl groups to increase density, surface tension, viscosity, refractive index, glass transition temperature and reduce conductivity.
To better understand the interactions between ILs and solutes, the characterisation of Kamlet-Aboud-Taft (KAT) parameters and the ET(30) electronic transition energy scale combined with molecular dynamics (MD) simulations was performed. Within the library of ILs a focus on PILs was made because of their extensive H-bonding capabilities and ease of synthesis. The KAT parameters include π* (dipolarity/polarizability), α (H-bond donating ability) and β (H-bond accepting ability). This revealed that increased alkyl chain length increases β while decreasing π*, α and ET(30). Notably, hydroxyl groups had the opposite effect. The β value of the PIL was shown to be predominantly based on the anion where the nitrate anion was found to be more influential than carboxylate anions for increasing PIL polarizability and reducing β. Radial distribution functions were used to determine atom-atom distances and correlate them with KAT parameters. This showed increased polarizability aligned with greater cation-anion distances and anion-anion distances, and the increase in β correlated to a decrease in cation-cation distances.
Next, the previously synthesized library of ILs, as well as common ionic salts, were used to investigate their effect on the model protein HEWL. ILs were used at concentrations of 1, 10, 50 and 100 mol% while the salts were used at 1 mol%. A high energy synchrotron based small angle X-ray scattering (SAXS) method was used for the rapid analysis of samples, which provided structural information on protein size, shape, and aggregation. This enabled a high throughput screening study to correlate IL structural moieties and protein structural stability. The hydroxyl group was highlighted as a potential protein stabilising group at higher IL concentrations, with ethanolammonium acetate, ethanolammonium formate, diethylammonium formate and ethanolammonium propionate supporting non-aggregated HEWL at 50 mol%. Noticeably, an IL concentration of 1 mol% most effectively supported native HEWL structure across almost all ILs while high concentrations of ILs (50 and 100 mol%) often increased HEWL aggregation. Ionic salts at 1 mol% were shown to align with the Hofmeister series while the ILs did not fit within this series due to the complex nature of IL specific ion effects and ion pairing.
To further the investigation of specific PILs on protein structures, a study was conducted on the structurally similar proteins HEWL and HL. PILs were used due to their similar H-bonding properties to water, which has caused speculation of their potential protein stabilizing ability. However, the literature involving proteins and ILs has shown ambiguous results when comparing the effect of a PIL across proteins. Therefore, a selection of 5 PILs were chosen from the previous protein study for their varying effects on HEWL stability and used at 1, 10 and 20 mol% in water. Through a combination of size exclusion chromatography (SEC)-SAXS and capillary SAXS, the effects of PIL and protein concentration on protein aggregation were investigated. The effect of PILs was mostly consistent across proteins and despite them increasing protein aggregation as compared to buffer, the 1 mol% PILs were the most effective concentration for supporting monomeric proteins. The chaotropic nature of the nitrate anion was highlighted as both 10 and 20 mol% ethylammonium nitrate had minimal aggregation for either protein. However, SEC analysis highlighted the differences in the aggregation of both proteins in buffer; where HEWL is monomeric, and HL has a small number of aggregates. Overall, this work showed that despite similarities in protein structure, these proteins had significantly different aggregation behaviour.</p
Titanium Hollow-strut Lattice Metamaterials by Laser Powder Bed Fusion
No full textDr. Noronha investigated the design of titanium hollow-strut lattices and established their manufacturability guidelines by laser powder bed fusion additive manufacturing. The manufactured titanium lattices exhibited mechanical properties that surpassed the empirical limits of cellular metallic materials with comparable relative densities. The research findings extend perspectives on metallic lattice materials.</p
Returning to sport after a COVID-19 shutdown: understanding the challenges facing community sport clubs
No full textRationale/Purpose: This study investigates the challenges of returning to sport after a COVID-19 shutdown of sport from the perspective of community sport clubs (CSCs). We explore the relationship between the challenges CSCs identified and the challenges the nation’s lead sport agency identified; and similarities or differences in the challenges faced by different types of CSCs. Design/methodology/approach: Concept Mapping (online) with 57 CSCs in Victoria, Australia. Findings: CSCs identified eight clusters of challenges related to returning to sport after the COVID-19 shutdown (in highest to lowest mean impact rating order): volunteers; club culture; health protocols; membership; finances; facilities; competition; and governance and division of responsibility. Cluster impact ratings differed by club location, competitive season, venue type, club size, and type of sport offered. Practical implications: The challenges CSCs face returning to sport are more complex and broader than current national guidelines suggest, with previously existing challenges exacerbated and new challenges emerging. Listening to CSCs is essential to understanding the nuances of, and support needed to address the complex context-specific challenges to returning to operations after a COVID-19 shutdown. Research contribution: Understanding the challenges and how they differ for CSCs as they return to sport
Traversing TechSex: benefits and risks in digitally mediated sex and relationships
No full textBackground. Digital technologies play a significant role in people’s sexual and intimate lives via smart phones, cameras, dating apps and social media. Although there is a large body of research on the potential risks posed by these technologies, research on benefits and pleasures is limited. Methods. This study explored digital sexual practices, including perceptions of risks and benefits among a sample of Australian adults (n = 445). Data were collected in 2020 via an online survey. Descriptive and bivariate analyses were undertaken to identify significant relationships between demographic variables and the use of technologies in relation to perceived risks and benefits. The mean age of participants was 42 years, over half were women (58.5%) and identified as heterosexual (61.1%). Results. Findings reveal that use of digital media was common in participants’ sex lives and relationships; 60.3% of participants had viewed pornography online, 34.9% had used dating apps, and 33.9% had sent sexual or naked self-images to another person. Over one in three reported positive outcomes from this: 38.2% felt emotionally connected to their partners due to online communication; 38.0% agreed that digital technologies facilitated closer connections; however, the majority of participants were aware of potential risks associated with online sexual engagement, particularly non-consensual exposure of their sexual or naked images, with women expressing greater concern. Conclusions. Policy, legal and educational responses should be based on holistic understanding of digital sexual engagement, acknowledging the ways in which technologies can support sexual relationships while also building people’s knowledge and capacity to manage risks.</p
Improving Interpreting for Dementia Assessments – MINDSET study
No full textThe article discusses the MINDSET training package, developed to improve interpreter communication during dementia assessments in culturally and linguistically diverse (CALD) communities in Australia, which provide interpreters with specific training in cognitive assessments. CALD Australians face significant barriers to accurate dementia assessment and timely diagnosis due to language proficiency and other cultural factors.</p