VictorJuiz/thesis huggingface dataset:
Fast probing of many Earth models with full waveforms
Keywords: born approximation
seismology
global seismology
Rytov approximation
waveform modelling
first order approximations

Seismology is our primary method for inferring the structure and dynamics of Earth’s interior. A region of particular importance is the lowermost mantle near the core-mantle boundary. Detailed information about lowermost mantle seismic structures can be inferred by comparing synthetic seismic waveforms to those observed at Earth’s surface.
In this thesis, a forward modelling method is presented which is based on first order single scattering approximations. These include the well-known Born approximation (which involves linearly perturbing the amplitude of the waveform), as well as the Rytov approximation (which involves linearly perturbing the phase of the waveform) and a whole family of intermediate approximations termed Marks approximations. The computation of these first order waveforms is facilitated by time and space dependent waveform sensitivity kernels. Kernels are computed for each source-receiver pair, but they are independent of the perturbed model. Once the kernel is calculated, synthetic seismograms for many models are generated very quickly (≈ 7 s per model).
The applicabilities of the Born, Rytov and Marks approximations are tested by comparing to reference solutions computed with a fully numerical method. For small perturbations to the background model, an excellent agreement is found between the first order and reference solutions, providing validation of the method. The first order method breaks down with increasingly large and strong perturbations. The Rytov ap- proximation consistently performs better than Born (the worst) or Marks(intermediate). The method is valid for P, S and converted phases.
The first order method is used to generate synthetic P/Pdiff waveforms under the Rytov approximation for 500 models representative of the large low velocity province under Africa. The database of synthetic data is probed in a statistical manner; sets of models which fit certain supposed observations are presented.
In pursuit of (soft) power: Chinese artificial intelligence governance in an age of great power competition
Keywords: artificial intelligence
foreign policy
United States foreign policy
international relations
soft power
United States
technology
The People's Republic of China
policy
great power competition
China
geopolitics

The 2017 New Generation Artificial Intelligence Development Plan outlined the People’s Republic of China’s aims to become the world leader in Artificial Intelligence (AI) by 2030 and create a global example of an AI-powered & governed society. Much analysis of PRC AI strategy since has focused on how these goals build domestic and international influence to enhance China’s hard power capabilities. This work asks instead: How does China’s approach to soft power manifest in its efforts to become an AI superpower? Through studying Chinese national-level AI policies and subsequent overseas state messaging via directed content analysis, I found that U.S. understandings of PRC AI strategy are flawed due to their overpowering focus on its hard power implications. The Chinese model of AI governance may have more draw through soft power than previously recognized.
I further argue that a full understanding of the PRC’s AI strategy requires more study of how soft power considerations influence that policy. Strong parallels exist between China’s conception of soft power and its broader AI strategy, both of which emphasize the construction of a strong domestic foundation upon which global influence can be built. China’s emphasis not just on the governance of AI (the act of regulating AI or dictating its use), but also the governance through AI (the eployment of AI in society to aid in the act of governing) allows for the construction of a potentially comprehensive and example-setting model. This study can inform future studies of Chinese soft power and global AI governance norms. It also calls for U.S. policy actors to place more emphasis on revitalizing the domestic U.S. democratic model through AI, rather than framing key AI policies as direct competitive responses to the “China threat.”
Towards the total synthesis of stambomycin D
Keywords: asymmetric alkyne addition
deprotection
protecting groups
asymmetric synthesis
polyketides
aldol reactions

Stambomycin D, a 51-membered glycosylated macrolide, was discovered by a genome mining approach, and the predicted planar structure confirmed by NMR spectroscopic analysis. However, the sequence analysis-predicted stereocenters (except C28 and C50) remain to be validated. This thesis discusses efforts to achieve a chemical synthesis of stambomycin D to fully determine its stereochemistry, including the 'unpredictable' C28 and C50 stereocenters. To begin with, the stambomycin D aglycone was disconnected at C50 to reveal acyclic C1–C51 fragments, which could be divided into five smaller fragments (C1–C11, C13–C22, C23–C31 (1,3-anti or syn diol at C27 and C28) and C33–C48 fragments). The early chapters discuss the synthesis of these fragments as well as deprotection studies, and the later chapters focus on the union of these fragments. Regarding the order of combination, the C13–C22 fragment is coupled to the C23–C31 (1,3-anti diol at C27 and C28, this thesis only discusses the anti diol diastereomer) first to construct the C13–C31 framework. A deprotection study was successfully executed on this fragment. The subsequent union of the C13–C32 fragment and C33–C48 fragment gives the C13–C48 fragment, for which deprotection exploration was also carried out. Through these deprotection studies, we not only supported the sequence analysis-predicted assignment of most of the stereocenters of stambomycin D, but also paved the way for the deprotection of the acyclic C1–C51 fragment and ultimately synthesis of the entire macrolide.
Understanding and exploring behavioural change: eadiness to change and response to Cognitive Behaviour Therapy; recording of clients’ child dependants by mental health service staff and improving fluid restriction and quality of life in people receiving haemodialysis

Keywords: haemodialysis
cognitive behavioural therapy
case series
readiness to change
acceptance and commitment Therapy
ACT Matrix

There is considerable interest in identifying factors that predict outcome from psychological treatment. This review examines the relationship between readiness / stage of change at entry to CBT treatment and treatment attendance or outcome in people with mental health problems other than addiction. A systematic literature search identified 20 eligible studies of which 19 were included in the narrative synthesis. Seventeen explored the relationship between readiness and symptom outcome, with a majority (n=12) identifying at least one statistically significant relationship between variables, either directly or in interaction with another measure. A number of these also tested other associations which were non-significant. In contrast, five studies explored the association between readiness and treatment attendance, and findings were inconclusive. The review identified little evidence that the association between readiness and outcome varied according to clinical problem being treated or measure of readiness used. The five studies adopting an RCT design identified no evidence of differences in the relationship between readiness and outcome when comparing CBT to other psychotherapeutic interventions. Study quality was variable, and a range of methodological limitations and potential avenues for future work are discussed.
Modelling and simulation of compacting sedimentary basins
Keywords: sedimentation
mathematical modelling
basin

Hydrocarbons are found in rocks within sedimentary basins below the Earth’s surface. Whilst they remain a primary energy source, many hydrocarbon fields are nearing depletion, and new, more advanced exploration and recovery techniques are required to find new reserves and to sustain production. One such technique aims at predicting the evolution of pressure, porosity, and temperature profiles within basins from past to present, to determine whether there is potential for hydrocarbon generation in a certain location and also to reduce drilling risk.
In this thesis, we identify and mathematically model the primary geological processes within a sedimentary basin. We develop a fundamental model which describes both the mechanical and chemical compaction of sediments, and their influence on the porosity, pressure, and temperature profiles. We write our model in a general form which then sets up the framework on which we can add geological features, such as sills and fault lines. Such a generalised model, which can include these features in multiple dimensions, is rarely seen in literature.
We use the finite element method to develop a solver which can tackle our full model in multiple dimensions, and we test the validity of the solver through the method of manufactured solutions and error analysis. We discuss additional numerical techniques that can be used to model the deforming basin with respect to compaction and sedimentation. Our model is solved for the simplest case first, before we present simulations for varying geological situations. We examine the effects of a constant versus a porosity-dependent permeability model, varying rock viscosity values, different compaction models, and mechanical or chemical compaction (the latter of which is frequently neglected in literature and in industry). Then, we present simulations for basins in the presence of complex geological features, such as laterally varying stresses, faults, and sills. Finally, we summarise our key findings.
(Re)moving waste: caste, spaces, and materials in Delhi
Keywords: materials
spaces
waste
value
infrastructures and technology
caste

Delhi is faced with a burgeoning growth of discarded materials—commonly referred to as waste. This rapid increase is characterised by chaos and disorder in the management of waste. This thesis examines the disorder and its effects through the lens of materials, spaces, time, people, and infrastructures involved in the flow of waste through the city. I focus on three waste-related sites in Delhi—Balmiki colonies, the Bhalswa landfill, and recycling units in north-west Delhi—and show how discarded materials acquire different meanings in different contexts and subsequently shape the caste-, class-, and gender- based social relations and the social and economic value associated with waste work and waste workers. I demonstrate this by focusing on the technocratic infrastructure of waste management and by examining the human and caste-based infrastructure of waste management. I show how the growing privatisation of the waste management infrastructure and the use of technology alongside the Clean India Campaign are projected as symbols of modernity and cleanliness and are used to invisibilise the human and environmental dimensions of the waste crisis for political and economic profit. Simultaneously, I focus on waste workers—municipal sanitation workers, public private partnership-led garbage collectors, informal waste pickers, and recyclers—to demonstrate the varying nature of stigma, discrimination, and evaluation of waste work and waste workers. I illustrate how urban marginality has pushed not only Scheduled Caste communities’ workers but also many non-Scheduled Caste communities, such as Muslim and Hindu OBCs, into waste work, transforming their social relations and caste hierarchies at a micro level. Furthermore, I examine how the value of waste work varies from being reproductive (city’s livability) to productive (generating exchange value in waste materials), across different spatio-temporal axes and value chains, and how that shapes the way waste workers perceive themselves and their work.
Bankruptcy in early modern England: bankruptcy and insolvency in the early modern Court of Chancery, 1543-1628
Keywords: King James I
property law
bills of conformity
vulnerable debtors
Chancery record
early modern period
debt settlements
insolvency
Francis Bacon LC
debts
equity
land law
fraud
discharge of debts
bankruptcy
Court of Chancery
sureties
financial rehabilitation
sixteenth-century
Privy Council
archival materials
widows
debtor's prison
seventeenth-century
orphans

This thesis presents a detailed analysis of the Chancery practice in relation to both bankruptcy and insolvency between 1543 and 1628. The aim of the thesis is to improve our understanding of the foundations and early development of bankruptcy and insolvency law in England. The methodology of the thesis is primarily doctrinal, but it uses historical methods to trace and understand unexplored cases and other legal archival materials in Chancery records, and together with additional historical and literary sources puts the law into a social and economic historical framework.
The thesis shows that the Court of Chancery had two functions in relation to bankruptcy and insolvency. The survey of the records shows that the Court of Chancery exercised a review function in relation to the decisions of the commissions of bankrupts which were authorised to deal with bankruptcy matters in the first instance, including declaring debtors bankrupt. This meant that the Court of Chancery effectively worked as an appellate court for the decisions of commissions of bankrupts.
In addition to the review function, the Court of Chancery also had an equitable function in relation to insolvency matters. In its equitable function the Court of Chancery dealt with issues concerning insolvent debtors that were not regulated by statutory bankruptcy or the common law. This thesis breaks with conventional scholarship and shows that the Chancery practice in this area appears to have been very humane, with special care for the most vulnerable in society, and that ‘modern’ bankruptcy principles and ideas, such as the concept of insolvency by misfortune, voluntary bankruptcy, debt settlements (compositions), majority control and the discharge of debts, which have generally been attributed to the bankruptcy statutes of 1705 and 1711, were already applied in the Court of Chancery in this earlier period.
A cryogenic trap for microwave-driven quantum logic using 43Ca+ ions
Keywords: surface trap
trapped ions
calcium 43
microwave gates
laser cooling
two-qubit gates
laser-free gates

The encoding and manipulation of information using the quantum states of trapped ions currently represents one of the most promising routes towards the realisation of a universal quantum computer. Although quantum gates in this system were originally driven by lasers, an alternative approach that uses the magnetic field gradients generated by current-carrying structures integrated directly into the trap has gained traction in recent years. This laser-free approach offers a few advantages, but the implementation of fast two-qubit gates with fidelities below the threshold required for quantum error correction remains challenging. In this thesis I describe progress in an ion trap system aimed at improving the fidelity and speed of two-qubit gates driven by magnetic field gradients oscillating near the transition frequency of the qubit. Work is based on a hyperfine qubit in 43Ca+ that has not been used for quantum logic before. We operate at a static magnetic field of 28.8 mT, at which point the qubit frequency of approximately 3.1 GHz becomes to first order insensitive to field fluctuations, enabling an internal coherence time that is orders of magnitude larger than the duration of quantum gates. The strong magnetic field results in a complex energy level structure, with adjacent states in the ground level being split by several multiples of the linewidths of the cooling lasers. Nevertheless, we demonstrate cooling to a temperature of 0.5mK for a single ion, close to the Doppler limit, by exploiting dark resonances that form between fine-structure levels. Furthermore, we implement resolved-sideband cooling using two laser beams driving a Raman transition, achieving an average occupation number ¯n = 0.08 for the two-ion motional mode of interest. Experiments are carried out in a surface trap that is suitable for operation at room and cryogenic temperatures. It features a U-shaped microwave electrode, which produces a microwave magnetic field such that the field component coupling the qubit states exhibits a strong gradient, but significantly reduced amplitude around the trap centre. I discuss measurements of parameters that will impact twoqubit gate fidelity, such as heating rates, drifts in motional frequencies, ac Zeeman shifts and the spatial dependence of the microwave magnetic field. Furthermore, we demonstrate spin-motion entanglement for a single ion using the Mølmer-Sørensen scheme and present the results of initial attempts at a twoqubit gate, for which we measure a fidelity of 0.77(2). I also provide a brief analysis of dominant sources of error that will have to be addressed in future experiments.
Essays in finance
Keywords: financial markets
equity crowdfunding
maturity structure
gender
government debt management
information
wisdom of crowds
fundraising strategy

This thesis presents three empirical analyses that contribute to our understanding of how financial securities and intermediaries facilitate the allocation of resources between firms, consumers, and the government. Each paper investigates a distinct asset class and aspect of the resource allocation problem. The first paper explores the role of information in financial markets and the wisdom of crowds. The analysis uses a recently developed statistical technique to infer overlap in information sets of security analysts and develops a profitable trading strategy using analyst stock ratings. This finding highlights the prevalence of information diversity. The second paper focuses on government debt managers in national treasuries and finds that they actively choose the maturity structure of government bonds to minimize the expected costs of debt service while responding to demographic factors so as to enable risk-sharing across generations. The third paper leverages the new phenomenon of equity crowdfunding campaigns to disentangle entrepreneurial choices from investor preferences, differentiating the fundraising strategies that entrepreneurs pursue based on their experience and gender, and the funding outcomes they achieve. Taken together, these three studies contribute to our understanding of how intermediaries and securities allocate resources in various financial settings.
Breaking boundaries: a study of socio-cultural identities in archaic and classical western Sicily
Keywords: ancient Mediterranean
death and burial
ancient Sicily
identity
epigraphy

This thesis investigates the burial practices of western Sicilian settlements during the late Archaic and Classical periods, incorporating comparative epigraphic evidence. Specifically, it explores the processes of creation and assertion of socio-cultural identities among migrant and indigenous communities, rather than focusing solely on their pre-defined outcomes. The prioritisation of ethnicity in the definition of collective identities in this region and period continues to influence the ways the agents and dynamics of contact are conceptualised. Such ‘ethnic labelling’ is not only unwarranted in view of the available evidence, but also obfuscates our understanding of other types of identities and historical processes. To challenge these existing frameworks and heuristic models, this thesis analyses the burial evidence from Palermo, Monte Castellazzo di Poggioreale, Monte d'Oro di Montelepre, Himera and Solunto, and draws on comparative epigraphic evidence from the curse tablets and Meilichios horoi of Selinunte, and the tophet of Mozia. By examining the markers and features used by western Sicilian communities to assert and negotiate their social identities, this thesis reveals the complex ways in which social hierarchies, economic drivers, historical circumstances and regional intervisibility shaped funerary and epigraphic practices. This thesis argues that patterns (and discontinuities) in these practices were not imposed by pre-defined ethnic rationales, but were rather selected by local communities in response to their unique context of social mobility, polity interaction and regional connectivity.
Conflict and society in the Anglo-Saxon landscape
Keywords: Anglo-Saxon
kingship
community
England
identity
warfare
landscape

This thesis is about the communication of collective identity in the landscape of Anglo-Saxon England. The goal of this research is to examine the way landscape was perceived in historical writing, and how landscape shaped the strategies by which political authority and collective identity was transmitted. Thus, this thesis is concerned with the relationship between practice and perception. From a historiographical perspective, this work will bring together three aspects of research that are sometimes not in simultaneous dialogue, namely: landscape, identity, and political history, providing an opportunity to synthesise major historiographical work, and demonstrate the interconnectedness of topics often dealt with in isolation. The central contention of this work is that the landscape was not ‘passive’ or mute; it was ideologically charged and fiercely contested. Not only did this guide political and social strategies, but it also underpinned historical writing, and the landscape itself could be used for rhetorical effect. The first major argument of this thesis is that Anglo-Saxon collective identity was layered and flexible, and it cannot be entirely determined or discussed in ethnic terms. As such, techniques that communicated collective identity needed to be robust enough to incorporate complex layers of Anglo-Saxon self-perception. It will be argued that ‘conflict’, as a broad process and set of interactions which were interpreted and communicated in historical writing, was an important way to locate collective identity in a landscape context. The places where battles took place and were memorialised, where assemblies publicly asserted the status of the military elite, and where acts of reconciliation took place were perceived as being significant and were incorporated into wider landscapes. Thus, the perception of the landscape, and the layers of meaning that it evoked in Anglo-Saxon society could subvert the traditional dichotomy of ‘core-and-periphery’ by emphasising the ideological significance of landscapes that might traditionally be understood as ‘peripheral’, such as forests, moors, or fens.
Multiparameter persistent homology of data
Keywords: random geometric simplicial complex
persistent homology

We explore two distinct topics in the field of topological data analysis: invariants and metrics for multiparameter persistence modules, and the homology of random geometric simplicial complexes.
We define a computable, stable invariant for multiparameter persistence modules, the multiparameter persistence landscape, and exemplify this invariant to be sensitive to the topology and geometry of multifiltered data sets. We prove a local bi-Lipschitz equivalence between two well-studied metrics for multiparameter persistence modules: the interleaving distance and the matching distance. A consequence of this equivalence result is that the multiparameter persistence landscape is a locally complete invariant for finitely presented multiparameter persistence modules.
Finally, we explore the asymptotic properties of Čech complexes built on compact Riemannian manifolds with non-empty boundary. We attain homological connectivity thresholds with identical leading terms. An upper threshold above which the Čech complex has homology isomorphic to the homology of the underlying manifold with high probability, and a lower threshold beneath which with high probability it does not.