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An investigation of the potential quantum advantage in next-generation timing and positioning techniques for satellite networks
No full textThis thesis investigates techniques for achieving high-precision timing and positioning in space. In particular, the potential of quantum properties such as squeezing and entanglement to overcome the standard quantum limit in precision is explored. Additionally, measurement strategies such as the temporal and spatial mode demultiplexing are also investigated. Despite their theoretical potential, the real-world performance of these techniques over inter-satellite free-space links has remained largely unexplored --- until now.
We begin by evaluating the performance of squeezed light for clock synchronization over inter-satellite links, developing a model that includes real-world issues such as beam diffraction, photodetection inefficiency, satellite pointing jitter, and excess noise. Using our model, we quantify the expected performance of a squeezed light-based clock synchronization scheme on satellites. We then investigate entanglement as an alternative resource for clock synchronization, identifying the unique constraints associated with this quantum property. Our findings offer novel insights into engineering criteria such as minimum squeezing level, minimum photodetection efficiency, and maximum pointing jitter, which will significantly influence future satellite-based experiments.
Next, we conduct a fundamental analysis of the temporal mode measurement strategy, focusing on the key nuisance parameters expected in practice. By treating these parameters as random variables with probability density functions, we determine the minimum information needed about the parameters for the successful operation of the strategy in real-world settings. Our findings can also be one-to-one mapped to the spatial domain. Finally, we extend the temporal mode strategy into the spatial domain and propose a solution for synchronization using coherent light and balanced homodyne detection. Our proposal presents a pathway to achieving sub-Rayleigh resolution in applications including satellite positioning and astronomical imaging. Furthermore, we analyze the impact of fixed and fluctuating satellite misalignment, beam diffraction, and photodetection inefficiency on our proposed solution.
Overall, this thesis contributes novel and important insights into the expected performance of quantum techniques for high-precision timing and positioning in space, laying the foundation for the development of next-generation communications, sensing and navigation infrastructure
A Light-weight Multiphase CFD Configuration for Liquid Hydrogen Flash Boiling
No full textLiquid hydrogen is known for its low saturation temeprature and low latent heat of
evaporation, the storage of which requires carefully designed insulation system.
However, limited by the measuring technique in such cryogenic environment, the
sensors cannot provide detailed measurement in evaporation rate, temperature
distribution and flow regime inside the tank. Therefore, CFD studies are applied to
compensate the gaps. Tani et al. [1] conducted an experiment on flash boiling
phenomenon in a large-scale liquid hydrogen storage tank and provided a bubble
nucleation based 3 stage phase change model. Kangwanpongpan et al. [2] proposed
an alternative CFD model with better fit to experimental result, based on volume of
fraction (VOF) and large eddy simulations (LES). Based on these results, this paper
proposed a lightweight alternative CFD configuration with RANS turbulent models,
which shows significant improvement on computational stability on larger calculation
timestep size and coarser mesh setup. The results show better fit to experimental data.
Moreover, comparisons are made between the geometries of previous papers by Tani
et al. [1] and Kangwanpongpan et al. [2]. Analysis is made on the cause of different
simulation behavior from CFD perspective. Finally, suggestions are made on how to
reduce BOG generation by appropriate outlet flow rate control
Uncovering the rules underlying mitochondrial volume homeostasis
No full textMitochondria are essential organelles responsible for energy production and metabolic functions in eukaryotic cells. Maintaining mitochondrial volume during the cell cycle is crucial for proper cellular function in many eukaryotes. Using fission yeast as a model organism due to its conserved mechanisms with mammalian cells and its small, consistent mitochondrial number, we investigated how cells maintain mitochondrial homeostasis.
We previously showed that mitochondrial partitioning during mitosis is stochastic, leading to unequal mitochondrial volumes in daughter cells [1]. It was unclear whether the cells detect and correct these deficits before the next division.
We used a microfluidic mother machine [2] combined with deep learning-based image analysis to track multiple generations of fission yeast. Our findings confirm that fission yeast cells exhibit ’sizer-like’ behaviour, growing to a critical size (∼15 μm) before division, thus maintaining cell size homeostasis. By comparing wild-type cells to mutants with significant mitochondrial partitioning errors, we found that cells maintain mitochondrial homeostasis through the cell sizer mechanism.
Importantly, we observed that cells with fewer mitochondria grew more slowly and had longer cell cycles than similarly sized cells with more mitochondria. This allows cells with fewer mitochondria to catch up in mitochondrial volume, thus maintaining mitochondrial homeostasis. This suggests that mitochondrial volume dictates the growth rate and timing of the cell cycle, rather than cell size alone.
Furthermore, we demonstrate that mitochondrial volume continues to increase exponentially throughout the cell cycle, even during the later stages, when overall cell growth transitions from exponential to decelerated growth. Theoretical modelling showed that exponential cell growth is possible due to exponential increases in mitochondrial volume and activity. Testing this with wild-type cells and cells lacking functional mitochondria (rho0), we observed that without mitochondrial function, cell growth shifts from exponential to linear, reinforcing the critical role of mitochondria in driving exponential cell growth.
In conclusion, mitochondrial homeostasis is maintained via the cell sizer, but mitochondrial volume plays a pivotal role in determining growth rate and cell cycle timing. Exponential cell growth is driven by the exponential increase in functional mitochondria, highlighting their essential role in the dynamics of cellular growth
Maranguka - A study based on publicly available evidence: A case study for ANZSOG's project on co-governance and trust in government
No full textThe objective of this case study is to examine co-governance, its interaction with trust and power relations as they relate to Maranguka, using documents which are in the public domain. This is part of a larger project for ANZSOG focusing on co-governance
The Development of Glucose Metabolism Inhibitors and Novel Synthetic Strategy towards 2,3-Disubstituted Indoles
No full textTumour cells exhibit enhanced glycolytic activity compared to normal cells—a phenomenon known as the Warburg effect. This metabolic change offers a promising therapeutic target, enabling selective cancer treatment with potentially fewer side effects. In previous work, BH10, a naphthoquinone derivative, was identified as a potent hit compound through a phenotypic screen based on oxygen consumption. BH10 exerted anti-proliferative effects by inducing mitochondrial oxidative stress and disrupting glucose metabolism.
In this study, Kelch-like ECH-associated protein 1 (Keap1) was identified as a potential BH10 target via avidin pull-down assays using biotinylated-BH10. To optimize biological activity and pharmacokinetic profiles, three series of BH10 analogues were synthesised. The first series of analogues included a naphthoimidazole core and a triazole ring with various terminal groups. The best compound displayed cytotoxicity against HEC1A cells with an IC₅₀ of 2.60 μM and improved pharmacokinetics in mice. The second series of analogues retained the BH10 scaffold. An imidazole derivative demonstrated a good balance between potency (IC₅₀ = 6.4 μM) and selectivity (index = 3.6). The best BH10-based organic salts in the third series exhibited remarkable anticancer activity (IC₅₀ = 22.97 nM) and a high selectivity ratio (41.43), suggesting strong tumour specificity. Molecular docking suggested consistent carbonyl-mediated interactions with a hydrophobic Keap1 binding pocket across all three series, supporting Keap1 as a potential key target.
In parallel, a metal-free method was developed to construct 2,3-disubstituted indoles, which are prominent in natural products and pharmaceuticals. The transformation involves Lawesson’s reagent-mediated C2–C3 bond formation from amidophenylglyoxylic esters via intramolecular cyclization. This reaction tolerates a wide range of esters, amides, and substituents on the aromatic ring, delivering structurally diverse indoles in moderate to good yields. The method was further applied to tricyclic and tetracyclic fused indole frameworks, introducing additional five- or six-membered rings fused at the N1–C2 position of the indole core. Mechanistic studies, including radical trapping and by-product analysis, support a carbene-mediated pathway, as evidenced by elemental sulfur formation. The method is scalable and compatible with further modifications, demonstrating its synthetic utility
CREATIVE INTEGRATION OF EGYPTIAN CULTURAL HERITAGE IN ELECTRIC VEHICLE STYLING
No full textThis paper explores the integration of Egyptian cultural heritage into electric vehicle design, aligning with Egypt Vision 2030 principles. The purpose is to investigate how ancient Egyptian symbols can inspire innovative electric vehicle styling and assess the educational outcomes of such a design project. Conducted as a coursework project at the October 6 University in Giza, 6 of October, Egypt, this initiative challenged product design students to design electric vehicle’s using symbols and motifs used in ancient Egyptian civilization. The methodology included four phases: 1) research and inspiration; 2) ideation and refinement; 3) digital modelling, and 4) physical modelling. The findings showed that integrating cultural symbols enhanced the aesthetic and symbolic value of the electric vehicle’s, fostering creativity and deeper cultural appreciation among students. Practical implications suggest that such designs can appeal to consumers seeking unique and culturally meaningful products. The originality and value of this paper lie in demonstrating how cultural heritage can be preserved and promoted through contemporary design, contributing to both educational outcomes and market innovation
The Role of Family and Peers in Mental Wellbeing Across Childhood and Adolescence
No full textMental wellbeing, defined as a positive state of mental health, is especially important during childhood and adolescence – critical developmental periods that have seen increasing rates of mental health diagnoses over time. Fortunately, these developmental periods offer key windows of opportunity for early intervention, with social relationships presenting potential sources of support. Yet, there remains limited understanding of how family and peer relationships influence overall wellbeing in childhood, or the mechanisms through which these relationships shape adolescent wellbeing. This thesis aimed to investigate the role of family and peer relationships in child wellbeing, as well as the underlying mechanisms linking these relationships to adolescent wellbeing. To facilitate these analyses, age-appropriate measures of mental wellbeing were first validated, adapted from the adult COMPAS-W Mental Wellbeing measure, following which the role of family and peers in changes in child and adolescent wellbeing was investigated. Following the thesis introduction, Chapter 2 outlines the development and validation of the self-report COMPAS-KIDS and parent-report COMPAS-PARENT wellbeing measure for children aged 5-7 and 8-12 years old. These measures demonstrated strong reliability, temporal stability, and validity against established criteria. Chapter 3 used these measures to explore the impact of parent and peer relationships as well as individual factors on child wellbeing over time. Among 5-7-year-olds, higher baseline child anxiety scores and peer problems scores were associated with lower child wellbeing scores, while higher levels of parent-child relationship closeness were associated with higher wellbeing levels over a 6-week period. For 8-12-year-olds, greater social functioning scores were associated with higher wellbeing scores, though girls reported lower wellbeing scores over time. Chapter 4 describes the validation of the COMPAS-W for adolescents aged 13-17 years, which also showed high reliability, temporal stability and validity. Three wellbeing profiles (languishing, moderate and flourishing) were evident across both neurotypical and clinical groups. Finally, Chapter 5 explored mechanisms linking relationships to wellbeing change in adolescence using this scale. At baseline, social support scores were positively associated with wellbeing scores through higher self-esteem scores; however, peer problem scores, cybervictimization scores, and loneliness scores were found to be negatively associated with wellbeing scores through lower self-esteem scores. Social support scores were also positively associated with wellbeing scores through active coping scores and cybervictimization scores were associated with wellbeing scores through active coping scores. Additionally, the negative association between cyber-victimization scores and self-esteem scores was found for neurotypical adolescents but not those with a clinical diagnosis. At follow-up, lower levels of loneliness continued to be associated with lower levels of wellbeing at 6 weeks, through lower levels of self-esteem. Overall, this thesis enhances the understanding of the role of parent and peer relationships in shaping child wellbeing, and highlights self-esteem and active coping as key mechanisms linking peer relationships to adolescent wellbeing. Future research could explore these dynamics over longer periods. Further, adolescent interventions may benefit from targeting self-esteem and coping skills alongside fostering supportive relationships and mitigating harmful ones to support mental wellbeing
Notation Is Not All That It Appears to Be: Roger Smalley on Changing Musical Relationships
No full textThis article considers Roger Smalley’s conception of notation from the point of view of the relationship between playing and writing. It argues that notation was one of the ways in which Smalley understood music history as a history of the relationship between composers and performers. Smalley’s version of music history included several turning points, the most significant of which came with Karlheinz Stockhausen’s music, which changed the relationship between performers and composers. This changing relationship brought new challenges to the notation of music, which mediates between different roles. The article focuses on different forms of notation, and the flexibility of notation, which Smalley nevertheless incorporates into a coherent picture of postwar music; and positions Smalley as one of the key figures of the changing relationships that new forms of notation mediate. The article concludes with close observations about one of the scores that Smalley annotated most heavily, David Lumsdaine’s Kelly Ground (1966). These observations build on the research of Emily Payne and Floris Schuiling, who have established the value of performers’ annotations in writing about the agency of musicians and the adaptability of notation
Global burden of 292 causes of death in 204 countries and territories and 660 subnational locations, 1990–2023: a systematic analysis for the Global Burden of Disease Study 2023
No full textBackground Timely and comprehensive analyses of causes of death stratified by age, sex, and location are essential for shaping effective health policies aimed at reducing global mortality. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2023 provides cause-specific mortality estimates measured in counts, rates, and years of life lost (YLLs). GBD 2023 aimed to enhance our understanding of the relationship between age and cause of death by quantifying the probability of dying before age 70 years (70q0) and the mean age at death by cause and sex. This study enables comparisons of the impact of causes of death over time, offering a deeper understanding of how these causes affect global populations. Methods GBD 2023 produced estimates for 292 causes of death disaggregated by age-sex-location-year in 204 countries and territories and 660 subnational locations for each year from 1990 until 2023. We used a modelling tool developed for GBD, the Cause of Death Ensemble model (CODEm), to estimate cause-specific death rates for most causes. We computed YLLs as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. Probability of death was calculated as the chance of dying from a given cause in a specific age period, for a specific population. Mean age at death was calculated by first assigning the midpoint age of each age group for every death, followed by computing the mean of all midpoint ages across all deaths attributed to a given cause. We used GBD death estimates to calculate the observed mean age at death and to model the expected mean age across causes, sexes, years, and locations. The expected mean age reflects the expected mean age at death for individuals within a population, based on global mortality rates and the population's age structure. Comparatively, the observed mean age represents the actual mean age at death, influenced by all factors unique to a location-specific population, including its age structure. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 250-draw distribution for each metric. Findings are reported as counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2023 include a correction for the misclassification of deaths due to COVID-19, updates to the method used to estimate COVID-19, and updates to the CODEm modelling framework. This analysis used 55 761 data sources, including vital registration and verbal autopsy data as well as data from surveys, censuses, surveillance systems, and cancer registries, among others. For GBD 2023, there were 312 new country-years of vital registration cause-of-death data, 3 country-years of surveillance data, 51 country-years of verbal autopsy data, and 144 country-years of other data types that were added to those used in previous GBD rounds. Findings The initial years of the COVID-19 pandemic caused shifts in long-standing rankings of the leading causes of global deaths: it ranked as the number one age-standardised cause of death at Level 3 of the GBD cause classification hierarchy in 2021. By 2023, COVID-19 dropped to the 20th place among the leading global causes, returning the rankings of the leading two causes to those typical across the time series (ie, ischaemic heart disease and stroke). While ischaemic heart disease and stroke persist as leading causes of death, there has been progress in reducing their age-standardised mortality rates globally. Four other leading causes have also shown large declines in global age-standardised mortality rates across the study period: diarrhoeal diseases, tuberculosis, stomach cancer, and measles. Other causes of death showed disparate patterns between sexes, notably for deaths from conflict and terrorism in some locations. A large reduction in age-standardised rates of YLLs occurred for neonatal disorders. Despite this, neonatal disorders remained the leading cause of global YLLs over the period studied, except in 2021, when COVID-19 was temporarily the leading cause. Compared to 1990, there has been a considerable reduction in total YLLs in many vaccine-preventable diseases, most notably diphtheria, pertussis, tetanus, and measles. In addition, this study quantified the mean age at death for all-cause mortality and cause-specific mortality and found noticeable variation by sex and location. The global all-cause mean age at death increased from 46·8 years (95% UI 46·6–47·0) in 1990 to 63·4 years (63·1–63·7) in 2023. For males, mean age increased from 45·4 years (45·1–45·7) to 61·2 years (60·7–61·6), and for females it increased from 48·5 years (48·1–48·8) to 65·9 years (65·5–66·3), from 1990 to 2023. The highest all-cause mean age at death in 2023 was found in the high-income super-region, where the mean age for females reached 80·9 years (80·9–81·0) and for males 74·8 years (74·8–74·9). By comparison, the lowest all-cause mean age at death occurred in sub-Saharan Africa, where it was 38·0 years (37·5–38·4) for females and 35·6 years (35·2–35·9) for males in 2023. Lastly, our study found that all-cause 70q0 decreased across each GBD super-region and region from 2000 to 2023, although with large variability between them. For females, we found that 70q0 notably increased from drug use disorders and conflict and terrorism. Leading causes that increased 70q0 for males also included drug use disorders, as well as diabetes. In sub-Saharan Africa, there was an increase in 70q0 for many non-communicable diseases (NCDs). Additionally, the mean age at death from NCDs was lower than the expected mean age at death for this super-region. By comparison, there was an increase in 70q0 for drug use disorders in the high-income super-region, which also had an observed mean age at death lower than the expected value. Interpretation We examined global mortality patterns over the past three decades, highlighting—with enhanced estimation methods—the impacts of major events such as the COVID-19 pandemic, in addition to broader trends such as increasing NCDs in low-income regions that reflect ongoing shifts in the global epidemiological transition. This study also delves into premature mortality patterns, exploring the interplay between age and causes of death and deepening our understanding of where targeted resources could be applied to further reduce preventable sources of mortality. We provide essential insights into global and regional health disparities, identifying locations in need of targeted interventions to address both communicable and non-communicable diseases. There is an ever-present need for strengthened health-care systems that are resilient to future pandemics and the shifting burden of disease, particularly among ageing populations in regions with high mortality rates. Robust estimates of causes of death are increasingly essential to inform health priorities and guide efforts toward achieving global health equity. The need for global collaboration to reduce preventable mortality is more important than ever, as shifting burdens of disease are affecting all nations, albeit at different paces and scales. Funding Gates Foundation