VictorJuiz/thesis huggingface dataset:
Theory and modelling of energy transport in quantum nanostructures

This thesis is concerned with quantum properties of excitonic energy transport in nanostructures that are embedded in a noisy environment. Of principal interests are ways to exploit this environment to facilitate the transport of energetic excitations.
The first research chapter deals with an extension to the 'standard' open quantum system picture, where the Hilbert space is split into three: system, environment, and a wider universe. This division is natural for many biological and artificial nanostructures. A new analytical method, based on a phase space representation of the density matrix, is developed for studying such division. The effects of the wider universe are shown to be captured by a simple correction of the environmental response function.
The second research chapter addresses the question: when do second-order perturbative approaches to open quantum systems, which are intuitive and simple to compute, provide adequate accuracy? A simple analytical criterion is developed, and its validity is verified for the case of the much-studied FMO dynamics as well as the canonical spin-boson model.
In the third research chapter, an intuitive model of a photocell is studied. The model comprises two light-absorbing molecules coupled to an idealised reaction centre, showing asymmetric dimers are capable of providing a significant enhancement of light-to-current conversion under ambient conditions. This is done by 'parking' the energy of an absorbed photon in a dark state which neither absorbs nor emits light.
In the final research chapter, a basic model for what can be thought as a "quantum brachistochrone" problem is investigated. Exotic energy configurations are found to yield considerable enhancement to the exciton’s transfer probability, due to similar mechanisms studied in the previous chapter.

Keywords: FMO
Open quantum theory
Density Matrix
Photocell
Excitonic energy transport
Advisor: Benjamin, S
Gauger, E
Surface mapping of faceted metal oxides by chemical probe-assisted NMR for catalytic applications

Semiconductive metal oxides are of great importance in environmental remediation and electronics because of their ability to generate charge carriers when excited with appropriate energy. The electronic structure, light absorption and charge transport properties have made the transition metal oxides an attractive material as photocatalyst. Recently, facet-engineering by morphology control has been intensively studied as an efficient approach to further enhance their photocatalytic performance.
However, various processing steps and post-treatments used in the preparation of facet-engineered particles may generate different surface active sites which may affect their photocatalysis. Moreover, many traditional techniques (PL, EPR and XPS) used for materials characterization (oxygen vacancy, hydroxyl group, cation…etc.) are not truly surface specific but analyzing a range from surface few layers to bulk. Accordingly, they can only provide very limited information on chemical states of the surface active features and their distribution among facets, causing difficulties to unambiguously correlate facet-dependent results with activity. As a result, this often leads to different interpretations amongst researchers during the past decades.
As the publications of titanium and zinc ranked top two among studies of first row of transition oxides in the past decades, this thesis will firstly review on the disagreements generated among researchers when they correlated the performance of ZnO and TiO2 with their facet activities based on traditional techniques. As there are shortcomings of these techniques in producing truly facet-dependent features, some results can be misleading and with no cross-literature comparison. To address these issues, we have developed a new technique "probe-molecule-assisted NMR" which allows a genuine differentiation of surface active sites from various facets. This surface-fingerprint technique has been demonstrated to provide both qualitative (chemical shift) and quantitative (peak intensity) information on the concentration and distribution of truly surface features among facets. In light of the new technique, this thesis will revisit the facet-dependent photocatalytic properties and shed light on these issues.

Keywords: Nuclear magnetic resonance
Surface features
Facet-dependent activity
Oxygen vacancy
Surface characterization
Advisor: Tsang, S
Policy experimentation and institutional power dynamics in China’s higher education reforms

In response to the challenges presented by unprecedented growth in higher education (HE) since 1978, China adopted policy experimentation (PE) as a means of introducing and testing HE reforms. This study involves four in-depth case studies of important reforms facilitated by policy experiments at different junctures of China's HE development: early 1980s, mid-late 1980s, late 1990s, and early 2010s. Within each reform, two elite universities as 'experiment points' (shi dian) were selected. Through cross-case analysis informed by semi-structured interviews and extensive documentary analysis, the study offers a holistic historical perspective on how PE has been used to bring about institutional changes in China’s higher education.
The study documents different rationales used for implementing policy experiments. State actors use PE to exert pressure on universities to introduce reforms, to lower associated risks and to strengthen the nation's overall HE policymaking capacity in a volatile and extremely heterogeneous context. For their part, university leaders have adopted PE locally to navigate China’s politically charged policymaking environment and to negotiate with state actors more favourable terms for reforms. Therefore, the PE approach enables state-university interactions and power negotiations that create and maintain 'strategy space' for consensus-building and institutional changes. It is an iterative process characterised by central-local interaction and intentionally ambiguous boundaries. The state, however, retains ultimate authority for legitimatising, selecting and expanding policy experiments. It is best understood as elite-enabled experimentation within existing political hierarchies.
Over time, China’s PE approach has become a semi-institutionalised mechanism for HE reforms. In the various policy experiments discussed in this study, PE functions as a productive, disciplinary and symbolic force at different stages of the policy process. Sometimes it appears to offer a genuinely productive mechanism for producing, identifying and negotiating innovative policy options that may be replicated at a larger scale; sometimes its essential use lies in its generated regulative effect; and sometimes it assumes more of a symbolic role allowing the government to acquire or consolidate reform legitimacy. Policy processes are mediated by these different uses of PE towards either reform efficacy or institutional conformity. This study situates these reforms within broader political, social, economic and historical contexts, and highlights the policy implications for higher education reform internationally.

Keywords: Education
Policy process
Education reform
Higher Education
China
Policy experimentation
Advisor: Mills, D
Ertl, H
Childhood pneumococcal pneumonia in Nepal

Pneumonia is the greatest cause of childhood mortality outside the neonatal period, yet the pathogen-specific aetiology of childhood pneumonia remains poorly defined. Vaccine probe studies estimate that approximately one third of children &LT;5 years of age with radiographic endpoint consolidation have pneumococcal pneumonia in settings prior to the introduction of pneumococcal conjugate vaccination (PCV), such as much of South Asia. 10-valent PCV was introduced to the Nepali infant immunisation schedule in August 2015.
I investigated childhood pneumococcal pneumonia in Nepal. I aimed to describe the prevalence of pneumococcal infection in children with suspected invasive bacterial disease admitted to Patan Hospital, Kathmandu, Nepal; to assess the impact of 10- valent PCV on pneumococcal pneumonia; and to assess two potential diagnostic tests for pneumococcal pneumonia based on the childhood response to pneumococci – assay of antibodies from lymphocyte supernatant (ALS) and analysis of differential gene expression (transcriptomics) – in children with pneumonia at Patan Hospital.
Pneumococci were the second-most most prevalent pathogen isolated from the blood of children between 2005 and 2016. Interrupted time series analyses of data from children admitted with pneumonia from March 2014–December 2016, showed a small increase (approximately 4%) in the odds of admission with pneumonia in comparison to non-pneumonia admis- sions temporally associated with 10-valent PCV introduction. However, it was not possible to adjust these time series analyses for extreme events including earthquakes (April 2015) and clean fuel shortages/increased air pollution (winter 2015/2016). In contrast, the indirect cohort method (a case-control approach in vaccinated vs unvaccinated children) showed vaccine effectiveness of 84% on the odds of nasopharyngeal carriage of vaccine-type pneumococci, but no effectiveness on pneumonia in these early data.
Assay of IgG ALS pneumococcal capsular polysaccharides was complicated by what appear to be non-specific binding to capsular polysaccharides (of both S. pneumoniae, particularly serotype 3, and H. influenzae). Assay of IgG ALS to the best-performing of five pneumococcal proteins assessed had a sensitivity of 88% and specificity of 71% for the discrimination of pneumococcal pneumonia from other bacterial pneumonia. A transcriptomic signature discriminated between pneumococcal pneumonia and other bacterial pneumonia with a sensitivity of 91% and specificity of 100%.
This thesis therefore contributes to knowledge of the clinical epidemiology of pneumococcal disease in South Asia. These data may also contribute to public health policy-making in the region. In addition, the development of two diagnostic tests for the aetiology of childhood pneumonia may be useful for future studies of childhood pneumonia aetiology.

Keywords: Vaccines
Transcriptomics
Epidemiology
Immunology
Pneumonia
Diagnostic tests
Advisor: Kelly, D
Pollard, A
Knight, J
'The living and the dying' : the rise of the United States and Anglo-French perceptions of power, 1898-1899

This thesis examines Anglo-French perceptions of power within the context of the rise of the United States of America. It uses several overlapping events falling within a moment at the end of the nineteenth century (1898-1899) – the Spanish-American War, the Dreyfus Affair and the Fashoda crisis – to explore various British and French actors’ perceptions of national power, decline, and international competition. It draws heavily on diplomatic material, but its methodology is primarily cultural. It examines ways in which various cultural assumptions affected perceptions of power and global events. It takes a particular interest in the relationship between ideas about gender and dimensions of national power. It focuses on contemporary preoccupations and assumptions, whether spoken or unspoken, and argues that they could prove determinative. External realities were refracted into perceptions that in turn drove prescriptions and policy.
The thesis juxtaposes perspectives from multiple states, thereby contextualizing or comparing British, French and occasionally American preoccupations with those of their transatlantic contemporaries. It draws upon archival sources which previously have been under-examined or approached from different perspectives and research priorities. Its exploration of the cultural dimensions of thought about national power and success is grounded in an awareness of the analysis and actions of certain diplomats and politicians involved in the more practical business of international affairs. Conversely, diplomatic and other records are situated within their cultural milieu, to better understand the context in which views about the international order were shaped. The thesis necessarily makes excursions into the history of emotions, since its actors' political analyses at times appear entangled and aligned with their emotional responses. The thesis therefore serves as an example of an international history that integrates diplomatic with cultural and emotional elements and demonstrates their mutual illumination.

Keywords: International history
Emotional history
Cultural history
Spanish-American War
France
United States
Dreyfus Affair
Transatlantic relations
Diplomatic history
Fashoda crisis
British Empire
Advisor: Clavin, P
Harris, R
Self-organised criticality in random graph processes

In the first half of this thesis, we study the random forest obtained by conditioning the Erdős--Rényi random graph G(N,p) to include no cycles. We focus on the critical window, in which, as studied by Aldous for G(N,p):

p(N) =   1+λN-1/3
N
We describe a scaling limit for the sizes of the largest trees in this critical random forest, in terms of the excursions above zero of a particular reflected diffusion. We proceed by showing convergence of the reflected exploration process associated to the critical random forests, using careful enumeration of classes of forests, and the asymptotic properties of uniform trees.
In the second half of this thesis, we study a random graph process where vertices have one of k types. An inhomogeneous random graph represents the initial connections between vertices, and over time new edges are added homogeneously, as in the classical random graph process. Each vertex is frozen at some rate, resulting in the removal of its entire component. This is a version of the frozen percolation model introduced by R\'ath, which (under mild conditions) exhibits self-organised criticality: the dynamics first drive the system to a critical state, and from then on maintain it in criticality.
We prove a convergence result for the proportion of vertices of each type which survive until time t, and describe the local limit in terms of a multitype branching process whose parameters are critical and given by the solution to an unusual differential equation driven by Perron--Frobenius eigenvectors. The argument relies on a novel multitype exploration process, leading to a concentration result for the proportion of types in all large components of a near-critical inhomogeneous random graph; and on a stronger convergence result for mean-field frozen percolation, when the initial graphs may be random.

Advisor: Goldschmidt, C
Martin, J
The origin and development of Maghribī round scripts. Arabic palaeography in the Islamic West (4th/10th-6th/12th centuries)

This thesis aims to study the origin and development of Maghrib&imacr; round scripts, i.e. the highly distinctive writing styles employed in the Arabic manuscripts and documents produced from the 4th/10th century onwards in the western Islamic world, and more specifically in the Iberian Peninsula, North-West Africa, and the Balearic Islands. In order to reconstruct the activity of Maghrib&imacr; calligraphers, copyists, and secretaries, and to follow the development of their practices, the present work lists and discusses the earliest dated material written in Maghrib&imacr; scripts, in chronological order: 123 non-Quranic manuscripts, 25 Quranic codices and fragments, nine chancery documents, and two private contracts, all of which produced between 270/883 and 600/1204. The palaeographic analysis of the scripts has made it possible to distinguish between different Maghrib&imacr; sub-styles and 'schools' of calligraphy, some of which have been given a new definition. A particular attention has been devoted to the geographical and historical context in which these scripts developed – i.e. Umayyad al-Andalus – and to the cultural, and even ideological implications of their use and diffusion throughout North-West Africa. Codicological aspects have also been taken into consideration, such as the quality of scribal supports, the composition of quires and gatherings, the methods of ruling the pages, the choice of inks and pigments of different types, the style and techniques of illumination. Where possible, the autoptic study of the material has been combined with the information offered by primary sources of various kinds (historical treatises, biographical dictionaries, handbooks for notaries...) so as to present a comprehensive picture of the Maghrib&imacr; scribal tradition until the Almohad period. The resulting image is that of a calligraphic culture as rich and sophisticated as the eastern one, which constituted a key element in the creation and promulgation of the Andalus&imacr; identity throughout the Mediterranean, but whose formative process and full aesthetic range were still poorly understood.

Keywords: Arabic palaeography
Advisor: Johns, J
Ultracold atoms in dressed potentials

Time-varying fields are widely used to extend the accessible range of trapping potentials for ultracold atoms. This work explores two very different examples of such fields, in the radiofrequency and optical regimes, whose interactions with trapped atoms can both be described in terms of the dressed atom picture.
Forming the basis of this work are radiofrequency dressed adiabatic potentials based on macroscopic trapping coils. Atoms are confined at the south pole of the resultant oblate spheroidal trapping surfaces. This work describes the extension of these potentials by two different methods: the application of multiple dressing radiofrequencies, and addition of a rapidly-scanned optical dipole trap.
This is the first experimental demonstration of a multiple-radiofrequency dressed adiabatic potential, explored using ultracold 87Rb atoms confined in a highly configurable double well. Due to the independent generation of each constituent dressing frequency, the depth of each trapping well and the height of the barrier are easily manipulated, enabling precise and reliable transfer of atoms between the available trapping geometries. Experimental work includes an exploration of the potential-shaping capabilities of the three-radiofrequency system, and characterisation of the potential landscape using radiofrequency spectroscopy with good agreement to the eigenvalues numerically calculated using Floquet theory. This initial exploration of multiple-radiofrequency techniques lays the groundwork for applications in studying double well physics in a two-dimensional system, and independent state or species selective manipulation of trapped atoms. The potential shaping capabilities of this method can also be extended by applying additional trapping frequencies.
In a supplementary line of experimental work, an optical dipole trapping system has been constructed, and the trapping beam aligned to the lower surface of the radiofrequency dressed trapping shell in order to sculpt the radial confinement. Beam shaping is achieved using an acousto-optic deflector, which can be used to produce either a composite array of static deflected beams, a rapidly-scanned painted potential, or some combination of the two approaches.
The development and extension of the experimental apparatus required to implement these enhanced dressed state potentials is explored, and the challenges of their experimental implementation considered.

Keywords: Magnetic trapping
Ultracold atoms
Multiple-radiofrequency adiabatic potentials
Radiofrequency dressed potentials
Bose-Einstein condensate
Adiabatic potentials
Advisor: Foot, C
Child guidance centres in Japan: regional variation in policy implementation and the family-bond

In contemporary Japan, approximately 85 per cent of children in alternative care are placed in large institutions. This contrasts with global discourse, encapsulated in the UN Guidelines for the Alternative Care of Children, and with practice in most OECD countries, which use foster care more extensively. Explanations for Japan’s outlier status often focus on a homogenous national culture, yet there is significant regional variation between local authorities in how policy is implemented, most readily visible in the percentage of children in foster care.
The title of this dissertation points to the three original contributions to knowledge of this work. The first is the rich ethnographic description of the child guidance centres and the decision-making process by which a child is removed from the family and placed into care. The second contribution is the explanation of regional variation in policy implementation. This is explained with reference to regional variation in resources, in norms, on the goals of care, the functions of different types of care, and the threshold until which a child is seen as being suitable for foster care, and in the organisational cultures of the child guidance centres.
The final contribution to knowledge is the construction of the family-bond, between child and 'parent'. This is understood as singular and discrete, that is, that a child can only have one family-bond at any moment in time. Where foster care is constructed as anything other than professional or semi-professional care in a family setting it is seen as a threat to the child’s family-bond with their natal parent. This dissertation argues that current attempts to increase the use of foster care by national and local authorities are likely to have limited impact unless they take this construction of the family-bond into account and focus on redefining the function of foster care.

Keywords: Adoption
Child Abuse
Family
Japan
Social Policy
Alternative Care
Foster Care
Social Work
Child Welfare
Advisor: Goodman, R
Seeleib-Kaiser, M
Fish ecology of mesophotic coral ecosystems

Mesophotic coral ecosystems (MCEs; reefs 30-150 m depth) are largely unstudied. This thesis uses the shallow reef to MCE depth gradient around Utila, Honduras, to address research questions in three themes: (i) understanding fish community ecological processes on MCEs; (ii) evaluating effective survey techniques for MCE fish research; and (iii) exploring the role of MCEs in the western Atlantic lionfish invasion. Around Utila, herbivorous reef fish declined with increasing depth, but remained present on MCEs, suggesting a possible role in structuring mesophotic benthic communities. To test this I artificially excluded fish from areas of the reef with controls for changing light levels. The results indicate strong effects of light availability on MCE hard coral, macroalgal and sponge coverage, while little detectable effects of fish exposure. Fish surveys play a crucial role in informing reef management, yet few studies consider how biases in survey techniques varies across depth gradients. I explored differences between baited-remote underwater video (BRUV) and diver-operated video (DOV) finding BRUVs consistently recorded more species regardless of depth, but that DOV is likely better for surveys of herbivores. I also assessed fish responses to divers using open-circuit SCUBA or closed-circuit rebreathers (CCR) and, while both recorded similar fish abundances, CCR divers were able to approach fish more closely. In addition, I conducted a meta-analysis identifying widespread invasion of western Atlantic MCEs by Indo-Pacific lionfish, with similar relative abundance distributions across the depth gradient to native range sites. Around Utila, MCE lionfish occurred at greater densities than on shallow reefs, with MCE individuals larger and more mature than their shallow counterparts. This suggests deeper lionfish populations may represent an extension of ontogenetic migrations, and act as a disproportionately large source of new lionfish recruits. Overall, this thesis provides insights applicable to the western Atlantic region more generally and highlights the need for MCEs to be considered by reef managers.

Advisor: Rogers, A
Exton, D