VictorJuiz/thesis huggingface dataset:
Engineering plasmonic light scattering with thin dielectric films: towards enhanced light trapping and novel sensing elements

Plasmonic research is becoming increasingly focused on the integration of noble metal nanostructures with planar devices to enhance their performance. Whilst the physics of noble metal nanoparticles at a simple interface is well studied, their behaviour inside a thin film structure is not. This work investigates the effect that placement in a thin dielectric film has on the excited modes and the directional scattering from various geometries of nanoparticle; the focus is on the fundamental principles but the application of this work in light trapping and nanoantenna design is also discussed. Research is conducted using finite-difference time-domain simulations and a custom built dark-field Fourier-space microscope, designed to interrogate individual particles and measure their angular scattering in thin films for the first time. It is found that the excited modes, large angle scattering and substrate coupling of the nanoparticles can be manipulated and improved considerably through careful choice of the materials and dimensions of the layers. Scattering from silver nanowires into a substrate is observed experimentally for the first time and an overcoating thin film is exploited to create highly directional emission, which is compared with nanoantennas in the literature. The potential to use this system as a novel sensing element is discussed. Following on from this, the nanocube patch antenna system is reviewed and its operation as a subwavelength plasmonic gas sensor is demonstrated for the first time to test for relative humidity using the Nafion polymer. This easily fabricable system shows superior sensitivities to other single-particle sensors across a range of humidities and simulations predict that by using sharper cubes and different deposition processes a further tripling of the recorded efficiency is achievable. The nanopatch structure can be readily adapted to detect a variety of other gases, and has the potential for integration into photonic circuitry.

Advisor: Smith, J
Watt, A
Assender, H
Generational change in gender gaps in political behaviour and attitudes: the roles of modernisation, secularisation, and socialisation

This thesis examines to what extent there are generational differences in gender gaps in political behaviour and attitudes, and what explains this generational variation. Generations differ considerably on factors such as women’s role in the family and the workplace, gender inequality, and formative experiences, and I argue this leads to different gender gaps for different generations. I examine such generational variation in gender gaps in vote choice, left-right self-placement, attitudes towards spending and redistribution, and attitudes towards gender-egalitarianism. Broad cross-national trends in Europe and Canada are identified, as well as country-specific patterns using Britain and the US as case studies. This thesis finds that generally, in the countries studied, men are more left-wing than women in older birth cohorts, whilst women are more left-wing than men in younger birth cohorts. This ‘gender-generation gap’ is produced through processes of modernisation, especially secularisation. In addition to this broad trend, the political context or zeitgeist during a generation’s formative years produces gender gaps in both vote choice and attitudes that differ between generations according to this socialisation experience. The influences of modernisation and such political socialisation interact to create complex patterns of generational variation in political gender gaps that differ across political contexts. For example, in the British case, women of younger cohorts are not more left-wing in their vote choice than men. These results suggest that we should focus on gender gaps at the level of generational subgroups in order to fully understand political differences between men and women. Furthermore, they predict that gradually, the gender gap where women are more left-wing than men will grow over time through generational replacement. However, they also indicate that this will not occur in all contexts, and that more work needs to be done to understand how the political context shapes gender gaps.

Keywords: gender gap
political generations
voting
Advisor: Fisher, S
Ambiguity and intermediation in the early moments of market formation: the case of the UK social investment market

Markets are arenas of social interaction for the exchange of products and services that are embedded in specific networks, cultures, and political relations. The study of how new markets come into being is a lively area of scholarly debate, and the purpose of this thesis is to shed light on the dynamics of these early moments of market formation. These nascent markets are characterized by the lack of shared meanings and settled rules around their participants, processes, and infrastructure. I approach them with arguments from economic sociology and from theories of organizations and institutions.
The empirical context is a longitudinal study of the UK social investment market from 2000 to 2015, a field that intersects the social, financial, and public sectors. Social investment refers to the combination of financial returns and social impact, but the contest over its meaning and practice is itself a part of this analysis. The core data collection is based on interviews, reports, field events, and online sources, which provide an empirical basis to understand the social, cultural, and political processes that are shaping this market.
I build on different traditions in the sociology of markets to explore changes over time in the rules, identities, practices, and dominant actors during the early moments of the UK social investment market. My first main finding is that the initial period of uncontested ambiguity is followed by efforts from mainstream organizations to reduce that ambiguity by reshaping rules and practices. This then results in a period of collaborative contestation, where peripheral actors challenge the core features of the field and hinder the path to stability. The second finding is about the role played by intermediary organizations in nascent markets, which consists of building the market infrastructure by connecting actors, developing a language, and establishing rules and practices.
These findings point to the importance of theorizing about ambiguity in the early moments of markets. I contribute to this endeavor by specifying some of its features and dynamics, and by emphasizing the centrality of intermediation. I also further our understanding of those markets that span across the worlds of business, policy, and civil society.

Keywords: Nascent markets
Ambiguity
Field emergence
Social investment
Impact investment
Intermediation
Early moments
Advisor: Ventresca, M
Jenkinson, T
Developmental response to brain inflammation

Perinatal inflammation contributes to neurodevelopmental diseases, and animal models have revealed that the inflammatory response within the central nervous system is age dependent. It remains unclear what intrinsic and/or extrinsic factors are responsible for this variation. Here, my aim was to discover the mechanisms responsible for the age-dependent changes in the inflammatory response of the brain by injecting interleukin-1 (IL-1β) into the brain of mice at postnatal day (P)7, P14, P21 or into adult mice.
A "window of susceptibility" was found at P14, which was associated with marked neutrophil recruitment and blood-brain barrier (BBB) breakdown, in response to a low dose of IL-1β. Evaluation of cytokine, chemokine, and adhesion molecule mRNA transcripts failed to reveal any specific increases in basal or reactive expression following the injection of IL-1β at P14. The extrinsic hepatic acute phase response (APR) was evaluated, but, once again, there was no evidence that an altered APR might account for the enhanced inflammatory response at P14. Indeed, an inverse relationship between the magnitude of the leukocyte recruitment to the brain and the APR was discovered. Enhancement of the APR with intravenous IL-1β after injection of a low dose of IL-1β into the brain was found to reduce the number of neutrophils and BBB permeability in the brain. While no molecular changes seem to account for the presence of the "window of susceptibility", a population of Iba-1+ large, flattened and irregular perivascular cells was discovered within the P14 brain, that may contribute to the increased leukocyte recruitment at P14.
Although variations in the brain inflammatory response with development were not fully account for, my results highlight the importance of the systemic inflammatory response on the outcome of acute brain injury and suggest that the systemic APR might be manipulated therapeutically to protect the brain in the perinatal period.

Keywords: Acute phase response
Postnatal development
Neuroinflammation
Advisor: Anthony, D
Stolp, H
Regulation of somatostatin secretion from pancreatic δ-cells

The somatostatin-secreting δ-cell is the least abundant cell type in the pancreatic islet and this may explain why very little is known about its role and function. In this thesis, I have characterized the SST-Cre-GCaMP3 mouse model in which the genetically encoded Ca2+ sensor GCaMP3 is expressed in somatostatin-expressing cells. Using these mice, glucose-induced somatostatin secretion was found to be inhibited by a KATP channel-dependent membrane depolarization and amplified by Ca2+ -induced Ca2+ release (CICR) mediated by activation of ryanodine receptor Ca2+ release channels.
Interestingly, glucose-induced [Ca2+ ]i oscillations in δ-cells did not correlate with electrical activity and persisted also when the cells were clamped at -70 mV, consistent with an important role of CICR. In addition, this study led to the finding that [Ca2+ ]i oscillations in different δ-cells display a synchronous behaviour upon glucose stimulation.
The role of somatostatin in the paracrine regulation of glucagon secretion was also addressed. Application of insulin inhibited glucagon secretion and stimulated somatostatin release. Using the SST-GCaMP3 mice, it was demonstrated that insulin exerts a direct stimulatory effect on δ-cells [Ca2+ ]i oscillations. After δ cell-specific ablation of insulin receptor, insulin had no inhibitory effect on glucagon secretion. This was paralleled by the loss of insulin-induced stimulation of somatostatin secretion.
Collectively, these data suggest that insulin stimulates somatostatin release, which in turn inhibits glucagon secretion. This finding highlights the pivotal role of somatostatin in the regulation of glucagon secretion. It also raises the interesting possibility of using a somatostatin receptor antagonist as an adjunct to insulin therapy to minimize the risk of hypoglycaemia.

Advisor: Rorsman, P
BOR2G: Building Optimal Regularised Reconstructions with GPUs (in cubes)

Robots require high-quality maps—internal representations of their operating workspace—to localise, path plan, and perceive their environment. Until recently, these maps were restricted to sparse, 2D representations due to computational, memory, and sensor limitations. With the widespread adoption of high-quality sensors and graphics processors for parallel processing, these restrictions no longer apply: dense 3D maps are feasible to compute in real time (i.e., at the input sensor’s frame rate).
This thesis presents the theory and system to create large-scale dense 3D maps (i.e., reconstruct continuous surface models) using only sensors found on modern autonomous automobiles: 2D laser, 3D laser, and cameras. In contrast to active RGB-D cameras, passive cameras produce noisy surface observations and must be regularised in both 2D and 3D to create accurate reconstructions. Unfortunately, straight-forward application of 3D regularisation causes undesired surface interpolation and extrapolation in regions unexplored by the robot. We propose a method to overcome this challenge by informing the regulariser of the specific subsets of 3D surfaces upon which to operate. When combined with a compressed voxel grid data structure, we demonstrate our system fusing data from both laser and camera sensors to reconstruct 7.3 km of urban environments. We evaluate the quantitative performance of our proposed method through the use of synthetic and real-world datasets—including datasets from Stanford's Burghers of Calais, University of Oxford's RobotCar, University of Oxford’s Dense Reconstruction, and Karlsruhe Institute of Technology’s KITTI—compared to ground-truth laser data. With only stereo camera inputs, our regulariser reduces the 3D reconstruction metric error between 27% to 36% with a final median accuracy ranging between 4 cm to 8 cm.
Furthermore, by augmenting our system with object detection, we remove ephemeral objects (e.g., automobiles, bicycles, and pedestrians) from the input sensor data and target our regulariser to interpolate the occluded urban surfaces. Augmented with Kernel Conditional Density Estimation, our regulariser creates reconstructions with median errors between 5.64 cm and 9.24 cm.
Finally, we present a machine-learning pipeline that learns, in an automatic fashion, to recognise the errors in dense reconstructions. Our system trains on image and laser data from a 3.8 km urban sequence. Using a separate 2.2 km urban sequence, our pipeline consistently identifies error-prone regions in the image-based dense reconstruction.

Keywords: autonomous vehicles
optimisation
machine learning
artificial intelligence
robotics
mapping
Advisor: Newman, P
Semi-sovereignty and relationships of hierarchy

Scholars of International Relations are increasingly interested in exploring differences between the members of international society, and the various forms of international hierarchy which connect these unlike actors. There are many points of intersection between these areas of interest, and a recent turn towards historical sociology, which puts the historical development of international society front and centre, and draws particular attention to the long-nineteenth century as a pivotal period in that development. This thesis seeks to contribute to these research programmes, by explaining variations between the so-called 'semi-sovereign' polities found throughout international society at the time. These entities existed throughout the entirety of the long-nineteenth century, and could be found across a range of regions. They varied by legal type, in terms of the rights they held and lacked, and in terms of the organizations and institutions they comprised and within which they were situated. This thesis accounts for variations between these polities in terms of four 'social logics': complexes of relations, processes, practices, norms, and concepts which, taken together, represent distinct, ideal-typical styles of interaction. Drawing on 'relational' International Relations theory and approaches from historical sociology, I argue that polities manifested and embodied elements of these prior logics, in a range of different combinations and configurations. With recourse to these logics – law, management, suzerainty, and cultural differentiation – we can account for where these entities came from, why they had the characteristics they did, and why they varied from one another, as well as from their fully-sovereign and wholly non-sovereign counterparts.

Advisor: Keene, E
The role of p97 cofactors SPRTN and FAF1 in DNA replication

It is well known that cancer cells are loaded with excess proteins. To survive this proteotoxic crisis cancer cells rely heavily on the ubiquitin proteasome system (UPS). Valosin containing protein (VCP) or p97 has recently emerged as a central player of UPS. Moreover, p97 inhibitors were shown to possess potent anti-cancer properties. Owing to the essential function of p97, it can be assumed that general p97 inhibition will be equally toxic to surrounding normal tissues. Interestingly, p97 employs diverse sets of cofactors to govern distinct biological pathways. Thus understanding the p97-cofactor interaction in specific pathways may give us the ultimate edge by allowing us to abolish those cancer specific p97-cofactor interactions in our fight against cancer. This thesis explains novel function of two bonafide p97 cofactors SPRTN and FAF1 in DNA replication.
Our discovery of a new human syndrome followed by its characterisation that monogenic and biallelic mutations in SPRTN leads to premature aging and juvenile hepatocellular carcinoma, have led us to identify the critical function of SPRTN in DNA replication. Our follow up work further revealed that SPRTN is a novel protease in humans and has the essential function in covalent DNA-protein crosslinks (DPCs) repair. To this end, we have found that SPRTN proteolytically removes CHK1 from chromatin, which is evolutionary conserved and vital for replication fork progression to preserve genomic integrity.
Additionally, this thesis also explains a novel mechanism through which FAF1 downregulation in cancer cells might promote genomic instability. Our data supports a model where the p97-FAF1 complex binds to ubiquitinated CDT1 and degrades it via the proteasome after CDT1 mediated replication initiation, to prevent re-replication and genomic instability.
The notion that high replication stress in some cancers can be utilised as an Achilles heel, led to the search for novel factors involved in DNA replication owing to its high therapeutic potential. Replication factors with enzymatic activities are especially appealing due to the relative ease of targeting them by small molecule inhibitors. This thesis thus highlights the great potential of the p97 systems in our battle against cancer.

Advisor: Ramadan, K
United in defeat: the causes and consequences of identity fusion in football fans

What motivates extreme pro-group action, such as heroism and self-sacrifice on the battlefield? Despite much scholarly attention in recent years, the question is yet to be fully explained. Recent research suggests that shared dysphoric experiences are one way of generating identity fusion, a visceral sense of 'oneness' between individual and group that has been shown to motivate willingness to fight and die for the group. Using two special populations - British and Brazilian football fans - this thesis investigates the causes and consequences of fusion. Football fan cultures are diverse, globally popular, and ripe for examining intergroup conflict. This thesis focuses on two related components of the 'shared dysphoria pathway' to fusion: emotional arousal (e.g. watching one's team suffer a particularly bitter defeat) and the sense of 'self-transformativeness' that ensues from intense, shared experiences. Across four studies, it is shown that for some individuals, sharing the agony of defeat can be emotionally and physiologically arousing to such a degree so as to transform their sense of personal identity. In turn, this leads to a more porous boundary between group and individual identities, i.e. individuals become 'fused' with their groups. Fused people are documented as engaging in some of the most extreme and potentially dangerous social behaviours we know. Two related consequences of fusion are examined: extreme pro-group action and outgroup hostility. Football hooliganism is a persistent, global problem, which is addressed in a fifth study. This thesis refutes past work suggesting that hooligans are social misfits, instead contending that hooligans are especially fused to their group and motivated to defend their 'brothers-in-arms', which results in outgroup violence. These findings suggest that a more thorough understanding of the causes and consequences of fusion could conceivably impact a great many areas, perhaps most importantly conflict resolution and policies relating to intergroup conflict.

Keywords: Football
Identity fusion
Cognitive anthropology
Football fandom
Group psychology
Social cohesion
Brazil
Social bonding
Hooliganism
Human evolution
Advisor: Whitehouse, H
Self-management of weight in adults with overweight and obesity: characterising and evaluating cognitive and behavioural strategies

Background: The majority of adults in the UK are overweight or obese, and many embark on weight loss attempts, often without professional support. This dissertation set out to hone in on the cognitive and behavioural strategies used by adults with overweight and obesity attempting to lose weight, particularly in self-guided attempts, and to test the relationship between use of these strategies and weight loss success. Methods: A new taxonomy and questionnaire were developed to provide a framework to identify the cognitive and behavioural strategies used by individuals during weight loss attempts. The taxonomy was used in a systematic review and meta-analysis of self-help interventions for weight loss and in a systematic review of qualitative studies of self-directed weight loss. The questionnaire was used in an observational cohort study in adults with overweight and obesity trying to lose weight. Results: The taxonomy and questionnaire consist of 117 strategies. The qualitative review illuminated a range of attitudes and beliefs towards these strategies and highlighted the centrality of interpretation of self-monitored data. The quantitative review found that self-help interventions led to greater weight loss than unsupported attempts to lose weight at six months. In the cohort study, despite heterogeneity in the strategies employed, coherent patterns of behaviours emerged for individual participants. Strategies related to motivational support, dietary impulse control, and weight loss planning and monitoring were associated with greater weight loss. Conclusion: This dissertation demonstrates that self-help interventions can lead to significant weight loss and provides results to guide the content of such interventions. It maps out a previously uncharted area and provides a set of tools for further research and intervention development.

Keywords: self-management
obesity
health behaviour
weight management
Advisor: Aveyard, P
Jebb, S