Real-time LEO satellite precise orbit and clock determination: Strategies and Challenges

To realize the various benefits brought by Low Earth Orbit (LEO) satellites in single-receiver high-precision GNSS-based Positioning Navigation and Timing (PNT) services, LEO satellite orbits and clocks need to be processed and delivered to users in real-time with precision of a few centimeters. While post-processing of cm-level LEO satellite orbits and clocks can be widely achieved, real-time processing faces various Challenges. When the number of LEO satellites increases, the observation data downlinked to the processing center may experience large and complicated discontinuities and incompleteness depending on the downlinking strategies. Even with the observations downlinked in real-time, the LEO satellite clock precision tends to be very sensitive to the continuity and quality of the GNSS real-time products. This study first introduces the procedure for ground-based cm-level real-time LEO satellite Precise Orbit Determination (POD), including near-real-time POD, short-term prediction, and ephemeris fitting/broadcasting. Next, the short-term predicted orbits and long-term predicted clocks of LEO satellites are introduced and properly constrained in filter-based real-time LEO satellite clock determination to achieve a precision of about 0.2 ns. Strategies to deal with sub-optimal observation data and GNSS products are explained. With the proposed methods, a Signal-In-Space Ranging Error at sub-dm to 1 dm can be achieved in practice

Clinical pharmacology studies of benzathine benzylpenicillin and benzylpenicillin

This thesis investigates the clinical use of benzathine penicillin G (BPG) in rheumatic heart disease and syphilis management, focusing on delivery constraints, safety concerns, and pharmacokinetics. Through qualitative research, systematic review, and population pharmacokinetic modeling, it examines provider apprehensions, logistical challenges, adverse reactions, and maternal pharmacokinetics. Despite BPG’s efficacy and favorable pharmacologic profile, findings underscore the need for optimized formulations, robust supply chains, and enhanced pharmacovigilance to ensure safer, more effective utilization, particularly in resource-limited settings

A survey of Australian dairy farmers’ attitudes to their business, its challenges and transitioning to alternative enterprises

Dairy farmers are grappling with serious business challenges, including rising operational costs, labour shortages, unstable milk prices, changing consumer preferences, long hours with minimal downtime and unstable weather patterns due to climate change impacts. Using a telephone-based representative survey and interviews with 147 Australian dairy farmers conducted in 2023, we employed a mixed-method approach combining quantitative and qualitative analysis to determine the challenges and primary concerns of the participants, as well as to explore potential solutions. Four key variables that contributed significantly to a binary logistic regression model of transition intentions were identified, namely: level of satisfaction with dairy farming, openness to exploring other agricultural alternatives to dairy farming, preference to receive financial and/or other support to remain in the industry and preference to receive financial and/or other support to transition into a different form of farming or business. This model accurately predicted the probability that farmers were considering transitioning away from dairy farming and the probability that they were considering staying in dairy farming. This deepens our understanding of the challenges faced by farmers in the Australian dairy industry, and provides policymakers, industry stakeholders and researchers with critical insights to facilitate transition pathways that will enhance farmers’ future sustainability

Singing Fishes: The Acoustic Ecology of Australian Fish Choruses

Passive acoustic monitoring of fish choruses can provide information on the distribution, habitat use, spawning dynamics, behaviour, local abundance, and ecological interactions of fish populations. The primary focus of this thesis was to map the contribution of fish choruses to Australian underwater soundscapes and investigate the ecology of these phenomena. This thesis has significantly advanced understanding of fish choruses in Australian waters, highlighting their ecological importance and providing a foundation for future research and management efforts

Aspirin in a novel mouse model of metabolic steatotic liver disease and its potential to prevent hepatocellular carcinoma

Aspirin shows promise as an accessible approach for preventing liver disease and hepatocellular carcinoma (HCC). Using mouse models combining gene editing and a NASH-inducing diet, aspirin reduced liver inflammation, fibrosis, oxidative stress, and hypoxia, while shifting immune cell profiles toward tissue repair. Key targets included COX-1 and hypoxia pathways. These findings highlight aspirin’s potential as a protective agent in chronic liver disease management and warrant further investigation into its mechanisms and role in HCC prevention

Spillovers and small spatial scale analyses: contributions from spatial economics

This editorial introduces the seven papers included in this issue of Spatial Economic Analysis (SEA). The papers analyse two important topics in spatial economics. The first addresses the spillovers between units in space, specifically the phenomena through which different locations interact and the multiple channels through which these interactions take place. The second topic is related to the obtainment and processing of information at small spatial scales. The topics that are covered in the first theme are hence how distance influences venture capital (VC) investment decisions; the role of various proximities in innovation and regional knowledge production functions; the effects on local labour markets caused by what happens in other markets nearby; the use of different types of proximities and different distances at the same time in estimating spatial autoregressive model with autoregressive disturbances (SARAR) models. On the second topic the issue covers a new two-step technique to estimate small spatial scale synthetic data from microdata and aggregate statistics as an alternative to spatial microsimulation; the use of satellite data to estimate consumer confidence and expectations; and the use of disaggregated general equilibrium modelling based on the partial hypothetical extraction approach in input–output systems to estimate the effects of emergency aid

Experimental and numerical investigation on the aging behavior of CFZnL composites in salt spray environment

This study develops a class of novel carbon-fiber-Zinc-alloy-laminated (CFZnL) composites, and investigates the modulus after salt spray aging. Experimental salt spray aging and tensile tests have been sequentially performed on CFZnL composites and conventional CFRP composites, to assess the aging behavior and residual tensile modulus. It has been observed that Zn alloy layer significantly enhances the aging-resistance due to moisture absorption. In addition, a multiscale modeling approach is proposed to predict the aging behavior and moduli of CFZnL and CFRP composites. Microscale models have been established to obtain the effective diffusion coefficients and effective properties of CFRP layers. Moreover, residual properties of CFRP and Zn alloy layers are calculated using an exponential degradation model. Then, they are introduced in the macroscale model for the tensile simulation. The numerical results concur well with the experimental ones, validating the accuracy of the multiscale modeling approach. It indicates that CFZnL composites with double-side Zn alloy layers possess superior aging-resistance than others in salt spray environment. Finally, the damage mechanisms are analyzed for the aged CFRP and CFZnL composites via experimental observations

Precarious Housing, Rental Assistance and Wellbeing: Unpacking Multi-Dimensional Links.

This thesis explores the complex multi-dimensional relationship between housing, rental assistance and wellbeing, which is spread over three main chapters. The first chapter explores the key drivers of transitions into and out of precarious housing. The second chapter analyses the impact of dwelling-based and neighbourhood-based precarious housing on mental wellbeing. The third chapter uncovers the effectiveness of rental assistance in preventing precarious housing among low-income renters