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Towards improving the accuracy of quartz OSL dating: investigations of the relationship between dose-response curve shapes and unreliable equivalent dose estimates
No full textThe abstract for this item has not been populated.</p
Modelling of the Idaho Calcine Waste for Hot Isostatic Pressing Canister-filling Process
No full textThis thesis presents a comprehensive study on the modelling of the Idaho Calcine waste for the hot isostatic pressing (HIP) canister-filling process. The Idaho calcine waste, classified as high-level radioactive waste, necessitates immobilisation to ensure long-term environmental safety. Traditional methods such as cementation and vitrification have been employed for waste immobilisation, but these approaches have inherent limitations. The HIP process, which applies high temperature and pressure to immobilise waste in a durable, monolithic form, identified as a promising alternative. However, being an emerging technology, the development of HIP for handling radioactive material involves several critical challenges, including accurately replicating the flow properties of the hazardous Idaho calcine waste and of its scarce non-radioactive simulant, which are essential for canister-filling process design.This research primarily focuses on developing calibrated discrete element method (DEM) models that accurately replicate the flow properties of both the Idaho calcine waste simulant and the actual radioactive waste. The objectives include a thorough literature review on HIP canister-filling processes and DEM applications, performing powder characterisation tests on a high-fidelity Idaho calcine waste simulant, developing robust calibration procedures for the Edinburgh Elasto Plastic Adhesion (EEPA) contact model and simulating the HIP canister-filling process under various conditions. Experimental work involved characterising the Idaho calcine waste simulant using standard test methods, conducting HIP canister-filling experiments with novel nozzle designs and validating the DEM models against experimental data.Key findings highlight the effectiveness of DEM modelling in predicting the bulk material behaviour of the radioactive Idaho calcine waste and its simulant in powder filling processes. The calibrated DEM models demonstrate high accuracy in simulating flow dynamics and packing behaviour within the HIP canisters. This predictive capability is crucial for ensuring homogeneous packing, mitigating void formation and optimising the canister-filling process and canister design. Additionally, the models provide insights into particle interactions and the HIP canister, fundamental for understanding compaction behaviour under HIP conditions.By selecting the correct calibration methods, this study closely emulates the bulk material properties relevant to a HIP canister filling process. Notably, the DEM model precisely predicts the mass balance within the simulated integrated filling system and accurately emulates the surface profile and fill level of the powder bed in a vibratory powder filling study. Although DEM simulation is computationally demanding, advances in hardware have enabled this research to be conducted on desktop PCs with readily available components, allowing for the simulation of complex bulk material scenarios, such as the multi-unit operation integrated HIP canister-filling system presented in this thesis.The implications of these findings are significant. By accelerating the development and enhancing the safety of emerging nuclear waste technology, this research contributes to the broader goal of sustainable and safe nuclear waste disposal. Leveraging the analytical capability of DEM, which to date has limited application in the nuclear industry, underscores the importance of a multidisciplinary approach to solving complex engineering problems. The successful simulation of the radioactive Idaho calcine waste not only marks a significant advancement in nuclear engineering but also offers a versatile analytical method adaptable for different types of high-level radioactive waste with varying bulk material properties.However, scaling up the HIP canister-filling system to accommodate industrial-scale applications remains a key challenge. Future work will focus on refining DEM models to better simulate the complexities associated with large-scale operations, including the effects of particle size distribution, shape irregularities and the influence of air. Additionally, there is significant potential in coupling DEM with nuclear kinetics for dosage assessment, which could enhance nuclear health physics by ensuring better protection and safety measures. Further developments will aim at optimising the HIP canister-filling process, improving overall efficacy and reliability as a nuclear waste immobilisation technique. This includes tackling challenges such as predicting HIP canister deformation under elevated temperature and pressure to minimise defects in the final waste form.The research underscores the importance of a multidisciplinary approach, combining the body of knowledge from bulk materials handling, nuclear engineering, HIP technology, immobilisation of radioactive materials, computational modelling and rapid prototyping to address the complex challenges of nuclear waste management. Future research will explore advanced computational techniques and algorithms to enhance the accuracy and efficiency of DEM simulations, potentially integrating machine learning methods to predict material behaviour under various conditions. Continued efforts will also be made to ensure that the HIP process meets stringent environmental and regulatory standards, with ongoing validation of DEM models through experimental data to ensure compliance with safety and environmental guidelines. These findings and future developments pave the way for enhancing the maturity of emerging nuclear waste management solutions, ultimately contributing to long-term environmental safety and sustainability of nuclear technology.</p
Silence and Inarticulacy in Wordsworth’s <i>Prelude</i>
No full textThis thesis discusses how different kinds of silence and inarticulacy function in Wordsworth’s Prelude. In this autobiographical poem, silence enables various kinds of connection at different points in the poet’s life. Silence facilitates a more immediate connection with nature for the child Wordsworth, enables the commemoration of the dead for the adult Wordsworth, and enables the older poet to reflectively compose the poem. The poet is not only interested in solitary silence. I introduce a distinction between silence and inarticulacy in The Prelude to analyse the poet’s interest in what lies beyond words in a social context. When recollecting social encounters he had as a young adult, the poet reveals a preoccupation with other people’s inarticulacy. These encounters challenge the poet to consider what can be revealed by what people do not or cannot say. As well as exploring what other people leave unsaid, the poet makes explicit his own inarticulacy. The attempted recollection of the poet’s past inarticulacy produces a poetic inarticulacy. Instead of seeing this inarticulacy as necessarily a failure, the poet connects the feeling of promise he had trying to articulate experiences in nature with the feeling of trying to articulate his own memories and imaginative thought. In these ways, the poet demonstrates a deep interest in what lies beyond sound, beyond others’ words and beyond his own. This thesis aims to reveal ways in which the poet uses silence, other people’s inarticulacy and his own inarticulacy in The Prelude to better express the nuances and power of deeper-than-verbal experience.</p
Radiobiological Effectiveness of Charged Particle Therapeutic Beams: Experimental Derivation,Application for Treatment Optimization and Radiation Protection of Astronauts
No full textThis thesis explores various applications of silicon-on-insulator (SOI) microdosimeters, specifically for space and aviation application, neutron monitoring in mixed radiation fields, as well as relative biological effectiveness (RBE) derivation for treatment planning systems (TPS) verification in proton and heavy ion therapy (HIT). Microdosimetry investigates the stochastic deposition of energy in a micron sized site in order to determine the biological effects that would be experienced by human cells in various radiation fields. SOI microdosimeters were conceived and developed by the Centre for Medical and Radiation Physics (CMRP) at the University of Wollongong (UOW), in Australia in order to supplement the current gold standard in microdosimetric measurements - the tissue equivalent proportional counter (TEPC) for radiation protection purposes in space, and address shortcomings of the TEPC for routine clinical applications in particle therapy.With an increasing push towards space exploration, it is vital to fully understand the risks associated with space travel not only to the astronauts, but also to the electronics on board the spacecraft. The presence of mixed radiation fields in space, makes it difficult to accurately distinguish between components, as heavy ions, while being less abundant, possess high linear energy transfer (LET) which can cause greater biological damage to cells. While it is possible to measure the macro doses associated with space travel, determining the biological effects on cells is difficult on a micron scale. The ability of an SOI based microdosimetry system to be utilized in a low dose rate, mixed radiation fields is investigated in the first part of this thesis. By utilizing several heavy ion radiation fields, it was possible to replicate the radiation field encountered in space and investigate the quality of the radiation and assess the potential biological impact on human cells. The response of the SOI microdosimeter in a mixed radiation field containing neutrons is also investigated. Neutron are difficult to detect in mixed radiation field environments. With the aid of a 10B4C thin film converter, it was found to be possible to separate the epithermal, thermal and fast neutron component from other radiation components. Additionally, a new 2 μm thick active layer SOI microdosimeter is extensively characterized and applied for thermal neutron detection in a heavy ion beam with successful detection of the thermal neutron component.The next part of this thesis, explores the radiation hardness and charge collection properties of a new layout design SOI microdosimeters to determine the limits of their exposure to ionizing radiation and whether the device could withstand typical doses in space and QA measurements. An ion beam induced current (IBIC) technique is utilized using a microbeam probe at the Centre for Accelerator Science (CAS) at the Australian Nuclear Science and Technology Organization (ANSTO) with low energy carbon ions possessing high LET which is raster scanned over the microdosimeters. By mapping the position of the ion beam with time, it is possible to generate charge collection efficiency (CCE) maps and better understand the charge collection properties of the devices. It was found that the microdosimeters with this new design were fabricated with different specifications, i.e. on a support wafer if higher resistivity, leading to unwanted charge collection from the substrate of the device. To alter the intrinsic properties of the substrate, the microdosimeters were irradiated with high doses of gamma radiation from a Co-60 source. Following this irradiation, the microdosimeters were then rescanned by the IBIC beam, and new CCE maps were generated to further investigate the unwanted charge collection. The findings of this part of the thesis showed important recommendations for future designs of SOI microdosimeters, as well as showing their ability to tolerate typical doses encountered in space and particle therapy, furthering the case for their applicability for space radiation monitoring and QA measurements in particle therapy.The third part of this work, explores the ability of the SOI microdosimeters to predict the RBE of various heavy ion beams at various clinical, and experimental facilities, as well as demonstrating the first ever experimental verification of LETd optimized plans for proton therapy. This final section of the thesis demonstrates the ability to accurately predict RBE values for heavy ion therapy (HIT) in real time using the modified microdosimetric kinetic model (mMKM) and an improved biological weighting function (IBWF) known as the V79-RBE10 BWF, while also accurately measuring LETd in proton therapy - something that has never been shown before.Overall, this thesis successfully shows and justifies the use of SOI microdosimeters for monitoring of radiation effects for astronauts during space missions, as well as its viability in a new domain of QA for particle therapy.</p
Evaluating Economic Empowerment Policies and Firm Performance: Insights from South Africa's Broad-Based Black Economic Empowerment Policy
No full textThis thesis investigates how economic empowerment policies impact firm performance and address racial inequality, through the lens of South Africa’s Broad-Based Black Economic Empowerment policy. Central to understanding the need for such policies is South Africa's legacy of racial inequality, rooted in its apartheid history. The focus is on the persistent racial inequality within the corporate sector, despite the implementation of B-BBEE more than thirty years ago, which was aimed at redressing the socio-economic inequalities from apartheid. This thesis consists of three studies, each examining a different yet related component of the B-BBEE policy and its impact on South African firms.In the first study I explore how the South African government has used accounting technologies to manage the pervasive issue of racial inequality. Premised on Foucault’s notion of governmentality, I conduct a qualitative case study using publicly available archival data to determine the extent to which accounting techniques have helped to shape policy responses to racial inequality. I show that accounting techniques and calculations give visibility to the problems of government and help design a programme to solve racial inequality. The lived experiences and impacts of racism in the workplace have been problematised, turned into statistics, and used to rationalise the need for ongoing government intervention in solving the problem. These processes underpin the development of the scorecard system, which measures the contributions firms have made towards minimising racial inequalities. This study augments the existing body of Foucauldian literature by illustrating how power dynamics can be counteracted. I further show that in governmental processes, accounting can exhibit a dual role, and these roles are not always subordinate to the analysis of political realities. The case of B-BBEE reveals the unintended consequences of utilising accounting to control the conduct of individuals or groups.In the second study, I evaluate the B-BBEE policy’s effectiveness in reducing racial inequality by examining the compliance of firms in different sectors over a span of 13 years. Using quantitative analysis, I investigate the strategic choices that firms make when deciding between generic and sector-specific scorecards. I also analyse how various sectors have adapted to the changing B-BBEE criteria. The results show that there was a general improvement in compliance after 2013, however there are still unique issues in certain sectors. This study offers important insights into the differences in compliance across sectors, emphasising the significance of customised strategies in the execution of policies.In the third study, I examine the relationship between B-BBEE compliance and firm performance, considering both financial and non-financial performance. I apply cross-sectional OLS regression analysis and find a positive relationship between compliance and financial performance, especially within highly competitive sectors. I further find that the 2013 B-BBEE Act amendment has varying effects on different sectors, with a stronger impact in certain sectors and less in others. Moreover, I find that B-BBEE compliance improves value within the ESG framework, implying that the policy can be a valuable strategic resource for business. This study contributes to the existing literature by integrating financial and non-financial performance, showing how B-BBEE compliance can improve both business performance and sustainable competitive advantage.This thesis advances theory and offers practical implications for policymakers and management. This thesis contributes to the broader discussion on the interlinkages between the compliance costs, financial performance and social accountability. The findings emphasise the significance of adaptable and industry-specific solutions for ensuring compliance, while also demonstrating a positive business case for B-BBEE policy.</p
Enhancing evidence-based decision making in healthcare by addressing meta-analytic methods
No full textSystematic reviews (SRs) are considered the gold standard of evidence in decision making in healthcare. SRs attempt to provide an objective summary of an evidence base by identifying all available primary studies on a specific topic. This process often includes a meta-analysis, a method used to statistically combine results from two or more primary studies, thereby condensing the evidence into a single effect estimate. SRs and meta-analyses have the potential to greatly influence patient care and outcomes and so the methods used to conduct SRs and meta-analyses need to be carefully considered.Traditional pairwise meta-analysis models only have the capability of incorporating data for one outcome of interest for a maximum of two comparison groups and are commonly used in practice. However, innovation in meta-analysis methodology means that more complex meta-analysis models are available which are capable of specifying the extent of the missing outcome data (MOD) in each study. Other models are able to incorporate outcome data for multiple outcomes or multiple comparison groups to be meta-analysed simultaneously. In practice, it is rare for no missing data to be present in the primary studies or for only one outcome or treatment of interest to be meta-analysed in a SR, meaning that there is great potential for uptake of these newer models. It has also proposed that using these models may increase the robustness and precision of results from meta-analysis, increasing their ability to accurately reflect the true effect and inform clinical guidelines to promote evidence-based practice.The central hypothesis of this thesis is that accounting for missing data, analysing multiple outcomes simultaneously or conducting a network meta-analysis will increase the robustness of meta-analyses and change the precision of the effect estimates. This hypothesis was tested by conducting three separate SRs with each containing a complex meta-analysis model to incorporate additional information and a naïve meta-analysis model to serve as a comparison.Firstly, the impact of accounting for MOD in meta-analysis was explored by conducting an overview of SRs with meta-analysis evaluating the impact of lifestyle interventions during pregnancy to reduce postpartum weight retention (PPWR). Results from these meta-analyses were re-analysed using the same data of the outcome and additional information about MOD. There were three SRs identified through database searching which included a total of 15 randomised controlled trials (RCTs) and 4 cluster RCTs across the SRs. All SRs identified showed statistically significant favourable effects of lifestyle interventions but conducted an available case analysis (ACA) which ignores the extent of MOD during analysis. Inconsistency varied across the SRs (I2 = 0% - 60%). In an updated analysis of all 19 trials included in the previous SRs, PPWR was lower for the intervention group than the control group and was statistically significant (MD: -0.80, 95% CI: -1.30, -0.30). There was substantial inconsistency (I2=51.3%, p=0.234). These results were compared to a meta-analysis which accounted for MOD by assuming that, on average, missing participants from the intervention group retained 0.5kg more than observed participants on average and that missing control participants retained the same amount of weight as observed participants. In this analysis, the effect of lifestyle interventions to prevent PPWR was reduced to -0.63 and remained marginally statistically significant (95% CI: -1.17, -0.08). Inconsistency was also reduced (I2 = 17.1%). The differences between results from this analysis and the ACA were analysed using a robustness index (RI) where a RI A SR of cohort studies evaluating the impact of preeclampsia (PE) on offspring blood pressure was conducted to allow comparison of results from a pairwise meta-analysis model to a multivariate meta-analysis which was used to analyse both systolic blood pressure (SBP) and diastolic blood pressure (DBP) simultaneously. After database and handsearching and study selection, 42 cohort studies comparing blood pressure of offspring born to preeclamptic and normotensive pregnancies were identified. Of these 42 studies, only seven provided estimates which were adjusted for key confounders. In univariate 2-level random effects meta-analyses of effect sizes adequately adjusted for confounders, offspring of preeclamptic pregnancies had higher SBP and DBP than offspring born to normotensive pregnancies (SBP: 2.07 mmHg, 95% CI: 1.33, 2.82; DBP: 1.26 mmHg, 95% CI: 0.49, 2.04). In multilevel multivariate meta-analysis, there were 21 effect sizes of SBP and 18 effect sizes of DBP extracted from the seven cohort studies. The effect of PE on offspring SBP was stronger (MD: 2.32 mmHg, 95% CI: 1.53, 3.11) but the effect of PE on offspring DBP was smaller and no longer statistically significant (MD: 1.04 mmHg, 95% CI: -0.12, 2.20). The borrowing of strength (BoS) statistic was calculated using the variance of the pooled effects from both pairwise and multivariate meta-analysis. BoS was 51.4% for SBP and 33.4% for DBP, indicating that a sizable proportion of the pooled effect was calculated from correlated evidence.The final study was a SR of probiotics and maintenance therapies, including polyethylene glycol (PEG), mineral oil, lactulose and other commonly used treatments, to treat functional constipation in children. This enabled comparison of pairwise and network meta-analysis for the effect of probiotics as compared to control for the outcomes of defecation frequency (BMs/wk) and treatment success as defined by the study authors. After database searching, handsearching and study selection there were 49 RCTs selected for inclusion. Ten RCTs compared probiotics and placebo directly and were pooled in a pairwise meta-analysis. The pooled effect for defecation frequency was small and not statistically significant (MD = 0.19, 95% CI: -0.14, 0.51) while the pooled effect for treatment success was marginally statistically significant (RR=1.48, 95% CI: 1.03, 2.13). Heterogeneity in the analysis of both outcomes was high (I2=86.0% for defecation frequency, I2=74.1% for treatment success). When direct and indirect evidence from all 49 RCTs were combined in a network meta-analysis, pooled effects for the comparison between probiotics and placebo were increased for the outcome of defecation frequency (MD = 0.57, -0.13, 1.27) but smaller for treatment success (RR=1.40, 95% CI: 1.06, 1.85). The variance of pooled effects was smaller in network meta-analysis and BoS was 24.5% and 40.6% for defecation frequency and treatment success respectively. This was equivalent to a gain in information of 2.5 and 4.8 studies of a similar size to that included in the analysis.The findings of this thesis demonstrate that the pooled effects of meta-analyses are influenced by the statistical model used. Accounting for MOD in sensitivity analyses revealed some instances where results from an ACA were not robust to MOD when compared to a sensitivity analysis. Precision around effect estimates was greater in multivariate and network meta-analysis, indicating that these models may be more effective in detecting small effects. These differences in effects could influence conclusions of SRs and may affect patient care when findings from SRs are translated into practice. Given the increase in robustness to MOD in effects from meta-analysis which account for MOD, and in the precision of estimates from multivariate meta-analyses, coordinated efforts from researchers and educators are needed to increase the use of these tools which are not often used in practice. The promotion of these tools could be implemented in meta-analysis guidance documents with a discussion of the potential benefits to encourage their uptake. Promotion of more complex meta-analysis models may also involve increasing the knowledge of SR authors about the limitations of naïve pairwise meta-analysis to incorporate additional information about MOD, multiple outcomes and multiple treatments. This may in turn improve the quality of meta-analyses as a whole by preventing the misuse of naïve models, which may result in improved evidence-based decision making in healthcare.</p
Person-Organisation Fit and Misfit: Definitions, Measurement, and Application in English and Chinese
No full textDespite the richness of Person-organisation (PO) fit and PO misfit studies, the definition and measurement of fit and misfit are still “elusive”. The interaction between the person and the work environment is such a broad topic that researchers usually define and measure PO fit and PO misfit based on their research interests. However, the researcher-oriented approach detaches fit and misfit from the psychological meanings. In another vein, the “elusive” nature of fit and misfit makes cross-cultural studies more troublesome.We start this doctoral thesis with a critical overview and a brief literature review of PO fit, PO misfit and their relevant constructs. Considering the absence of a systematic review of misfit, a systematic review of PE misfit and its relevant constructs in English literature was conducted, this can be found in Chapter 2. Although the measurements of misfit vary, the most commonly used instruments measure degrees of similarity of values and low scores of similarities are interpreted as misfit. In Chapter 3, an examination is made on how low scores of value congruence became the currency of perceived employee misfit (PEM) studies. This is achieved using a historical lens. In Chapter 4, the research focus shifts to examining PO fit in an Eastern context (i.e. China). As a result, Chapter 4 provides a systematic review of the relevant studies conducted in China and written in Chinese. A Chinese model of PE fit is tested in Chapter 5. This chapter provides new insights into this concept in an Eastern context. This doctoral thesis ends with a conclusion of how these findings complement existing knowledge about fit and misfit and suggest future research directions.This doctoral thesis makes theoretical contributions by providing the first systematic review of employee misfit. It also critiqued the traditional approach to employee misfit measurement and called for the adoption of a quantitative approach that asks employees about their misfit directly. When fit and misfit step into other cultural contexts, the extant Western fit and misfit theories become “void”. This doctoral thesis systematically investigates how fit, the product of Western literature, is interpreted, defined, and measured in China. We extend PO fit in the Eastern context with an empirical study and replicate and extend a Chinese model of person-environment fit into PO fit.</p
Research on Advanced Vehicle Cabin Suspension Control System
No full textEfficiently solving the balance between ride performance, energy consumption, and stability in commercial vehicles is important. Except for the trade-off between handling stability and ride comfort, huge energy consumption remains a challenge for traditional suspension systems and interconnected technologies. Research shows that cabin systems are more suitable for implementing different isolation techniques to increase ride comfort, as the cabin directly affects the vehicle and occupant dynamics. Electromagnetic systems in cabin suspension have emerged as a promising solution due to their lower energy consumption and cost-effectiveness. An electrically interconnected suspension (EIS) system with external electrical network (EN) uses mechanical-electrical analogies to solve the problem of complex circuits and cost consumption in traditional suspensions. A full-car EIS system with a 4-port EN has been proposed and optimized using genetic algorithm (GA) technology, which aims to enhance the ride comfort of the cabin. The thesis utilizes GA to optimize variable resistance parameters within the electrical network of the EIS system, aiming to achieve superior performance across multiple road conditions.Moreover, the thesis emphasizes the importance of verifying theoretical optimizations in actual tests. A Hardware-in-the-Loop (HiL) test platform is developed to evaluate the effectiveness of the optimized EIS cabin system accurately. Experimental results demonstrate the efficacy of the optimized EIS system in improving ride comfort and stability under various driving conditions. Comparison between the optimized EIS system and conventional passive suspension systems indicates that the ride comfort performance with the optimized EIS system in practical application has been significantly improved. Specifically, when the vehicle is driving at 50/ℎ, the cabin acceleration in the three motions of the cabin is decreased by 7.43%, 8.97%, and 18.56%, respectively; At a medium speed of 70/ℎ, these reductions become 8.70%, 31.14%, and 36.65%, correspondingly. Finally, at a high speed of 100/ℎ, the respective reductions amount to 17.33%, 23.65%, and 47.30%. It can be concluded that the EIS cabin system demonstrates good performance in terms of ride comfort after testing on the HiL experimental platform, enhancing the practicality of future research.</p
Changes in Australian rainfall and their links to large scale drivers of variability
No full textLarge scale changes in rainfall in Australia have been the subject of extensive previous study. Significant trends have been observed in seasonal rainfall around the country, such as increasing summer rainfall in the tropics and decreasing winter rainfall in southwest Western Australia. These changes are linked to anthropogenic factors such as land clearing, aerosol concentrations and increased greenhouse gas concentration. They may also be linked to changes in three drivers of internal variability affecting Australia. These drivers are the El Niño-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and the Southern Annular Mode (SAM). In this thesis, the observed changes in rainfall and their links to changes in these drivers are investigated. Throughout this work, station level rainfall data from the High Quality Daily and Monthly Rainfall datasets and gridded rainfall data from the Australian Water Availability Project are used in conjunction with the most commonly used indices for the climate drivers. Trend analysis performed on seasonal rainfall agrees well with prior work, particularly noting the strong declines in winter rainfall in the southwest, autumn rainfall in the southeast, and the strong increase in summer rainfall in the north. Rainfall variability during autumn and winter in the southwest is also declining, with fewer very wet seasons occurring, resulting in a decline in annual rainfall variability. Elsewhere, the seasonal rainfall variability is mostly increasing, particularly during summer in the north. The impact of the Millennium drought on these trends appears to have reduces an observed positive trend in rainfall prior to the drought in New South Wales. Positive trends are observed in each of the three climate drivers, with quantile regression analysis also indicating that the upper quantiles for ENSO and the IOD are increasing at a greater rate than the lower quantiles. The trends observed for these drivers do not appear to correlate well with observed trends in rainfall. Change point analysis performed on seasonal rainfall totals detects structural breaks in the time series of winter rainfall in southwest Western Australia (SWWA), with a very consistent time of change detected across the region. This change is a major factor in the observed negative decline in winter rainfall in the region. Changes are also detected in other parts of the country, in eastern Australia during spring and in northern Australia during summer, both contributing to increases in mean seasonal rainfall. Performing the change point analysis on the drivers of internal variability results in few significant change points being detected with meaningful links to the observed changes in rainfall. Some changes during summer for ENSO occur around the same time as some changes in rainfall in the north, but the increasing trend in ENSO since the change would imply a reduction in rainfall rather than the observed increase. A change in the IOD around the same time as those changes in SWWA is also detected, but the correlations between the IOD and winter rainfall in SWWA are very low. An analysis of changes in rain events indicates that extended periods of rainfall are expected to decline in length and rainfall volume across most of the country, with a notable exception being increases in the tropics during the monsoon season. Correlating these rain events with the drivers of variability supports this observation, especially when considering the observed positive trends in all three indices, though these correlations are weak and these drivers are therefore unlikely to be key drivers of observed change. The difference in how the SAM influences rainfall in southern Australia and areas further north is clear during winter, but less so during the rest of the year. These results are important in giving a clearer picture of Australian rainfall changes when it comes to drought or flood mitigation, but could be brought into a greater context if the analyses are repeated with rainfall on shorter time scales, such as sub-daily totals which are linked more with flash flooding. The changes observed here may also be limited by the relatively short length of the instrumental record in Australia, which extends back to the late 19th century. The use of an ENSO index which measures the temperature gradient across the Pacific may also allow for some conclusions to be drawn on changes in El Niño and La Niña cycles. The changes observed in this study may be part of a larger cycle on a much greater time scale, and so it is important to continue to build a complete record of historical Australian rainfall data, upon which these analyses could be repeated.</p
Unpacking Developers, Curriculum Leaders, and K-12 Teachers' Perceptions of Artificial Intelligence in Education
No full textArtificial intelligence (AI) technologies are rapidly permeating various sectors, and the educational domain is striving to integrate these innovations. However, a discord exists between the stakeholders involved—developers, curriculum leaders, and K-12 educators. Teachers face pressures to cover curricular content within constrained schedules, leaving limited time to comprehend and effectively utilise the AI tools promoted by curriculum leaders and developed by companies. This disconnect raises concerns about the suitability and successful integration of AI in educational contexts.The divergent practices of each stakeholder group have contributed to slow adoption rates, lack of understanding, and tensions in the field. This study aimed to explore these tensions by eliciting stakeholder perspectives to uncover convergences, divergences, and the varying levels at which their thoughts, beliefs, and values operate within the AI in education discourse.Employing a modified Delphi approach, this research engaged all three stakeholder groups in a two-round, open-ended interview process. Participants shared their perceptions on AI in education, allowing each group to establish a consensus. The individual group perceptions were then compared to identify areas of convergence, divergence, and the differing macro, meso, and micro levels at which their thoughts and agendas operate.The findings revealed nuanced viewpoints and priorities across developers, curriculum leaders, and educators, shaped by their distinct value systems and roles. While teachers emphasised pragmatic classroom-level (micro) considerations, curriculum leaders and developers exhibited more nuanced perspectives on AI's potential contributions, often operating at macro and meso levels, focusing on commercialisation, regulations, and social factors. Comprehending these divergent perceptions is crucial for understanding AI's current state in education and informing strategies to address challenges associated with the design, integration, and adoption of AI technologies.Despite convergence on certain topics, such as AI's potential roles, literacy needs, ethical concerns, and addressing disparities, the persistent divergence across macro, meso, and micro levels underscores the critical need for alignment and collaboration among stakeholders to effectively integrate AI in education. To rectify this misalignment and ensure responsible tool development and adoption, a shift towards participatory processes is imperative. Developers must actively engage with educators to gain comprehensive understanding of classroom nuances. Curriculum leaders and developers should prioritise supporting educators in acquiring AI literacy, moving beyond merely imposing technologies. AI-literate educators can then make informed decisions, selectively adopting tools that enhance teaching and learning while rejecting those that fall short.Ultimately, understanding perceptions and conceptualisations across stakeholder groups is important for harnessing AI's potential in education in ways that are safe and equitable, connected to the everyday realities of classrooms in order to leverage the transformative possibilities of AI in educational settings.</p