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Regularisation by multiplicative noise for reaction-diffusion equations with distributional drift
Get PDFIn this thesis we deal with regularisation by noise phenomena in partial differential equations caused by multiplicative noises. In particular, we study the solvability of stochastic reaction-diffusion equations in the case when the “drift” or “reaction term” is so irregular that it is not even a function, but merely a distribution in the Schwartz-sense. We provide the definition of solution, which is a priori not well-understood. We use Malliavin calculus to obtain estimates related to the density of the solution of the driftless equation, such as quantitative bounds on all Malliavin derivatives of the solution, and a quantitative nondegeneracy result for the first Malliavin derivative. We use these results to prove an “integration by parts” result for computing expectations of functions of the driftless equation. We also show the Lipschitz continuity of the Malliavin derivatives of the driftless equation in the initial condition, and quantify how well the driftless equation approximates the general case with (possibly distributional) drift. We combine the aforementioned results with state-of-the-art stochastic sewing techniques to prove a well-posedness result for the stochastic reaction-diffusion equation with distributional drift, derive stability estimates, and establish the temporal and spatial regularity of the solution. Moreover, we provide bounds on the H\"older norms of the density of solution of the driftless equation, and all of its derivatives
Controlling, evading, and maximising quantum thermalisation
Get PDFQuantum thermalisation is the process by which generic interacting many-body systems evolve such that local observables relax to their thermal equilibrium values, regardless of the system’s initial state. While progress has been made through the Eigenstate Thermalisation Hypothesis – a powerful conjecture describing thermalisation in closed quantum systems – practical methods to control or exploit this process remain elusive. This is a crucial challenge if we aim to use interacting many-body systems as a foundation for quantum technologies. After providing introduction to quantum thermalisation and many-body chaos in Chapters 1-2, the core of this thesis explores theoretical frameworks for controlling quantum thermalisation using tunable quantum systems, with a strong emphasis on experimental realisability. In Chapter 3, we introduce a chiral spin-chain model and demonstrate that, when tuned to the appropriate coupling regime, it exhibits maximally thermalising behaviour, similar to the well-known Sachdev-Ye-Kitaev model. Leveraging this property, we implement the Hayden–Preskill teleportation protocol, showing that maximal scrambling can improve the protocol’s timescales. In Chapter 4, we step back and introduce quantum many-body scarring as a mechanism for evading thermalisation. We showcase how the PXP model – a limit of the experimentally realised Rydberg atom platform – allows for tunable quantum many-body scars by means of varying the detuning or chemical potential. This approach unveils a continuous family of scarred initial states that extends beyond low-entangled product states. Finally, in Chapter 5, we investigate a distinct information-scrambling process – “Gaussification”. In this process, which bears some resemblance to thermalisation, the states which are initially interacting, i.e., possess non-Gaussian correlations and violate Wick’s theorem, progressively evolve into Gaussian ones. We demonstrate that Rydberg atom arrays can retain non-Gaussian correlations after a quantum quench in a way that is robust against experimental errors. Our conclusions are presented in Chapter 6 where we argue that the results presented in this thesis challenge the notion that thermalisation is an inevitable destructive force by offering several strategies to both resist it and harness it for applications in quantum-information processing
Evolution of competing populations in time-varying environments
Get PDFPopulations evolve subject to the conditions of their environment, which vary in time. Changes in the environment directly impact the evolution of the population, making an understanding of population evolution under environmental variability crucial to uncovering the evolutionary dynamics of natural populations. This thesis investigates the effect of the coupling between ecological dynamics, driven by varying environmental conditions, and population evolution. In particular, it considers the combined effect of demographic fluctuations (randomness caused by stochastic births and deaths in a finite population) and environmental variability on four models of competition in two-species microbial populations. These models are inspired by real-world issues such as antimicrobial resistance evolution and the establishment of unwanted mutants in healthy populations. In a constant environment, the behaviour in each model is understood and, in the motivating contexts considered, often leads to undesirable evolutionary outcomes. However, these dynamics change dramatically upon the introduction of environmental variability. The majority of this thesis focuses on environmental variability modelled by a dichotomous Markov noise controlling the carrying capacity of the population (the number of individuals it can typically support). This drives the population size of the community and thus directly impacts the strength of demographic fluctuations, providing a coupling between ecological and evolutionary dynamics. The case where environmental variability impacts both the reproductive capabilities of species and the carrying capacity is also considered. Due to the eco-evolutionary coupling, driven by environmental changes, interesting novel phenomena arise at the evolutionary level. In particular, in each model a preferred evolutionary outcome is motivated, and it is shown how appropriate conditions on environmental variability can promote those outcomes. These behaviours are investigated through extensive stochastic simulations and the development of analytical techniques
Young people’s narratives on their experiences of attending a school with an isolation space
Get PDFIn this research, I explored young people's experiences in mainstream secondary schools that use isolation practices. I draw upon a relational ontology and social constructionist epistemology (Burr, 2003; Gergen, 2009) to understand how participants co-construct meaning around isolation, both as users and as witnesses. I used a qualitative narrative methodology and the Listening Guide to gather rich narratives and analyse the layers of voice, identity, and meaning in the participants’ stories (McKenzie et al., 2021).
My literature review explored the historical roots of isolation practices in punitive traditions and behaviourist paradigms (Slee, 1995; Smith, 1981). These practices emphasise control over fostering learning or emotional growth (Barker, 2019; Foucault, 1975). Recent guidance advises that isolation should be proportionate and considerate of the young person’s welfare (Department for Education, 2024a). However, I found that this remains poorly defined, unmonitored, and lacks evaluation from those affected, the young people themselves (Power & Taylor, 2018; Sealy et al., 2023).
The narratives I heard constructed isolation as consistently punitive, restrictive and emotionally distressing, for those who were placed in isolation and those who witnessed it. All participants used the simile of a prison to describe isolation spaces and explored emotional dysregulation, stigma, and power within their narratives. Whilst some shared relief that isolation existed to deter their peers from being disruptive, its fairness, consistency and emotional impact were questioned. One participant expressed a desire to comfort those in isolation, demonstrating a capacity for co-regulation that is currently being prevented by isolation and punitive measures (Emerson & Frosh, 2009).
Through this research, I share the voices of young people and urge schools, educational psychologists, and policymakers to reconsider punitive approaches. I advocate for emotionally attuned, psychologically informed, evidence-based relational practices that promote regulation, inclusion, and dignity (Siegel & Bryson, 2018; Taylor & Scorer, 2025)
National Labour: “Quite dead” or “The coming force”? The Labour faction of Britain’s National Government under Baldwin & Chamberlain, 1935-39
No full textThe National Labour Committee, from 1937 the National Labour Organisation, was the last political party to provide Britain with a prime minister outside of Labour and the Conservatives and has to date been the longest-lived (and arguably most successful) party to break away from Labour. However, it currently represents a significant blind spot in the historiography of interwar British politics. Although the crisis and general election of 1931, and the Labour Party split they entailed, are well-understood, as are the ‘high politics’ of the National Government, practically nothing has been written on National Labour as a party.
This thesis aims to remedy this deficiency by examining National Labour as an institution in the period 1935-39. The general election of 1935 proved a bruising experience for the party, amidst the context of near-total lack of organisational activity and Ramsay MacDonald’s recent retirement from the premiership. Although the consensus to date has been that the poor performance in that election marked “the end of the road” for National Labour, in fact the next four years saw a remarkable and unexpected rebirth.
As MacDonald left the political stage, National Labour evolved from a London-based committee that supported candidates and published essays into a modern political party with constituency organisations, area councils and conferences and women’s and youth wings. The party’s personnel also changed, from being a rump of MacDonaldite defectors, to, by the end of the decade, a youthful core of progressive centrists, forward-looking and largely free from the baggage of 1931. Competitive internal elections, a steady trickle of prominent recruits and intense ideological clashes over appeasement indicate the emergence of a genuine institutional life by 1939, before the outbreak of the Second World War removed the party’s raison d'être
Assessing the sources, chemistry and trends of nitrogen oxides in the remote oceanic atmosphere
Get PDFNitrogen oxides (NO and NO2, known as NOx) are key species in the ozone cycle and thus indirectly affect the atmosphere's oxidising capacity, as ozone photolysis produces the hydroxyl radical, OH. In the tropical marine boundary layer (MBL), low emissions, high relative humidities and photochemical activity result in high OH production rates. Whilst it is important to understand the chemical processes that take place in the tropical MBL, this region is remote therefore mixing ratios are low and measurements are challenging.
NOx has been measured at the Cabo Verde Atmospheric Observatory (CVAO) in the North Atlantic since 2006, using a high-sensitivity chemiluminescence instrument with low detection limits. The data processing steps used at the CVAO have been validated through comparison with those used at the Kennaook/Cape Grim Baseline Air Pollution Station in Tasmania. The long-term dataset from the CVAO was used to identify trends in NOx mixing ratios, particularly the effects different air masses reaching the site have on NOx values.
Photostationary state (PSS) analysis was performed on NO2 and HONO measurements from the CVAO, revealing that our understanding of the chemistry in the remote MBL is incomplete. The underestimation of PSS NO2 has been attributed to missing oxidants converting NO into NO2, with measured peroxy radicals at the CVAO not sufficient to reconcile measured and PSS values. HONO PSS analysis indicates that the photolysis of particulate nitrate (pNO3) is the main source of HONO in this environment, but more work needs to be done to determine the factors driving the enhancement of pNO3 photolysis compared to that of nitric acid.
Current NOx mixing ratios are low enough that net ozone destruction is seen in the MBL, but understanding NOx cycling over the oceans is necessary as increases in NOx could result in a shift to an ozone production regime
Development of mathematical morphology and pattern recognition algorithms to characterize solar activity
Get PDFSolar activity acts as the primary driver of space weather, encompassing phenomena such as flares, coronal mass ejections, and solar energetic particles, which originate from distinct regions like sunspots, faculae, and granules. Predicting space weather is essential due to its significant impact on planetary atmospheres and human activities both in space and on Earth, including communication and navigation systems, power grids, spacecraft operations, astronaut safety, and aviation at high altitudes and latitudes. Sunspots, in particular, harbour intense magnetic fields that can trigger powerful solar eruptions and therefore require continuous monitoring. In recent years, automated identification methods have become increasingly common as the vast amounts of data from both ground- and space-based observatories can no longer be handled manually.
In this thesis, we developed mathematical morphology algorithms for automatic sunspot detection. Our results, compared with those obtained through manual methods, demonstrate comparable accuracy, enabling the extension of this approach to other solar features and image datasets. For instance, we applied a modified version of these algorithms to simulation-generated maps to identify magnetic flux rope structures in two active regions, capturing their distinct dynamics and, in one case, an eruption corroborated by Solar Dynamics Observatory (SDO) observations.
Mathematical morphology was further applied to extensive datasets to identify all coronal off-limb structures visible in SDO/Atmospheric Imaging Assembly (AIA) 304 Å images throughout nearly the entire Solar Cycle 24 (June 2010–December 2021). Statistical analysis of the properties of these features revealed significant trends, including distinct behaviours between high- and low-intensity coronal structures in terms of latitudinal distribution. Additionally, evidence was found for the existence of active longitudes, with coronal off-limb structures exhibiting a preferred longitudinal distribution pattern. These findings deepen our understanding of coronal activity and open new avenues for improving space weather forecasting
The Virtual Realities of Contemporary Post/apocalyptic Fiction
Get PDFThis thesis explores Virtual Reality (VR) technology as a model for interactive, body-led experiential reading. The objective is to make a case for VR as a narrative medium which invites the user to physically interact with immaterial phenomena. I propose that this exceptional phenomenological character of the VR user experience represents the possibility of affectively engaging with the cataclysmic change definitive of the contemporary epoch.
To analyse how VR can be put to literary work, I explore three contemporary post/apocalyptic fictions which imagine post-technological near-future worlds: Emily St. John Mandel's Station Eleven (2014), Don DeLillo's The Silence (2020), and Rumaan Alam's Leave the World Behind (2020). In my readings of all three texts, I identify the unique affinities between VR and the post/apocalyptic genre by showing how each
writer reimagines futurelessness as a productive, ahistorical place from which technology's synonymity with the future can be disrupted and reoriented towards the present.
To translate the properties of VR to literature, I draw on a range of theories and discourses, including metafiction, digital media theory, phenomenology, and philosophies of technology. By applying this combination of literary, digital, and philosophical theories to the literary novel, I hope to highlight the potential of VR as a medium which adds
interdisciplinary value to traditional literary criticism. Each chapter explores how the texts varyingly evoke the experiential properties of VR by adopting a discursive and reclamatory approach to the apocalyptic tradition and inviting alternate modes of reading.
The result, I hope, is a thesis which makes a persuasive case for VR as an alternative way of approaching traditional literary criticism and an affirmation of the value of reading fiction to understand and affectively respond to contemporary concerns
Phase Behaviour and Structural Characterisation of Model of the Schefflera Elegantissima Leaf Intracuticular Wax
No full textThe plant cuticle acts as a crucial barrier against transpiration. New findings show that long-chain hydrocarbons in the intracuticular wax layer notably reduce water loss. It’s evident that complex molecules are crucial for plants. With the global population on the rise, it is increasingly vital to manage plant health to prevent crop failures and ensure substantial agricultural yields. This is particularly true as plant wax composition is known to alter in response to external factors, such as drought. (1,2) The traditional brick-and-mortar theory suggests water molecules navigate a complex pathway during cuticular transpiration. Understanding these pathways is key for agrochemical penetration of the wax layer.
The intricate composition of the intracuticular wax of the Schefflera elegantissima plant was simplified into two previously unstudied 2-component systems, and their phase behaviour was analysed. Following in-depth individual compound analysis, the study investigated the solid-liquid and solid-solid equilibria of C29-C31 n-alkane mixtures and C31-C30OH n-alkane-alcohol mixtures using DSC and XRD. Two novel equilibrium phase diagrams for the binary mixtures were developed based on the analytical results
Targeting neutrophil cell death as a treatment for multimorbidity
No full textMultimorbidity is the presence of two or more chronic conditions in a single person. Chronic inflammatory disorders account for ~70% of all worldwide deaths, with cardiovascular diseases (e.g., atherosclerosis) and respiratory conditions (e.g., chronic obstructive pulmonary disease (COPD)) frequently presenting together as a multimorbidity, due to shared risk factors. Neutrophilic inflammation is central to the progression of COPD and atherosclerosis, with the dysregulation of neutrophil cell death mechanisms causing prolonged inflammatory responses, damaging the surrounding tissues. This suggests that therapies targeting neutrophil cell death mechanisms (i.e., apoptosis and neutrophil extracellular trap (NET)osis) may be used to treat such conditions. Previous work indicates that the EGFR/ErbB inhibitor, neratinib, induces neutrophil apoptosis and increases efferocytosis rates in macrophages in vivo. Moreover, the PKCβII inhibitor ruboxistaurin has previously been shown to inhibit NET formation. This study presents findings in support of the ideas that: 1) Ruboxistaurin is able to significantly inhibit the production of NETs induced by multiple different pathways in human neutrophils in vitro. 2) Neratinib, is able to induce neutrophil apoptosis, and is also able to increase efferocytosis and phagocytosis rates of human monocyte derived macrophages (MDMs) in vitro (potentially via inducing elevated expression of MerTK on these cells). 3) Using an AAV-mPCSK9 induced model of atherosclerosis (in tandem with a high fat diet (HFD)), and an LPS induced acute lung injury model in combination, it is possible to develop a murine model of multimorbidity in vivo. 4) Using this murine model of multimorbidity, neratinib treatment induced multiple positive outcomes relating to the severity of inflammation observed between groups treated with neratinib and vehicle control groups. These findings suggest that treatments which target neutrophil cell death mechanisms represent viable therapeutic options for use in the treatment of chronic inflammatory disorders, and multimorbidity
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