VictorJuiz/thesis huggingface dataset:
A comparative study of homelessness and services to meet basic needs
Keywords: homelessness
social services
social policy
sanitation

People experiencing homelessness often have difficulty accessing resources to meet their basic needs for food and sanitation. However, services to meet basic needs—such as public toilets, soup runs, and day centres—have been under-explored in research concerning homelessness and the welfare state. Accordingly, relatively little is known about the ways in which these services fit into the extension of rights through the welfare state. This research examines evidence from policy documents as well as the perspectives of service providers, city government officials, and advocacy groups to investigate the following question: In what ways, if any, does the relative salience of social or civil rights in a welfare state affect the provision of services to meet the basic needs of people experiencing homelessness? Through a comparative analysis of New York and London, two major cities within the ‘liberal’ welfare regime, this study demonstrates that the provision of services to meet basic needs is fragmented, in both cases consisting of a mix of government, voluntary, and private provision. Additionally, the relative salience of social and civil rights affects the ways in which policymakers and service providers conceptualise poverty and need, as well as the claims advocacy groups make on behalf of people experiencing homelessness. Drawing from concepts in social citizenship and social exclusion, the analysis shows that these findings reflect differences in understandings of poverty, rights, and responsibilities in each city.
Aristophanes and the poetics of surprise
Keywords: semiotics
Greek comedy
humour
performance
reception
Aristophanes
typology
poetics

The purpose of this thesis is to examine the variety, the mechanisms, and the poetological intention of the effect of surprise in Aristophanic comedy, addressing the phenomenon not as a self-evident or unselfconscious element of comedy as a genre, but as an elaborate system which characterises the style of the specific dramatist. More precisely, the thesis analyses Aristophanes’ most prominent verbal, thematic, and theatrical modes of surprise from a typological perspective, and interprets them as comprising the key area in which the playwright claims and demonstrates his artistic superiority over rival genres and individual poets. In line with this purpose, two parallel aims of the thesis are to provide an original commentary on the passages under examination, and to promote the study of modern performances – a practice which has so far been either restricted to Classical Reception or only theoretically acknowledged (if at all) by mainstream philological scholarship.
Model misspecification and general Bayesian bootstraps
Keywords: Model misspecification
Bootstrap
Model uncertainty
Bayesian nonparametrics

This thesis explores how a Bayesian should update their beliefs in the knowledge that any model available to them, however useful, is wrong. A number of connections are made between ideas in the model misspecification, Bayesian nonparametrics and bootstrapping literatures. These have led to the development of novel methods for scalable Bayesian inference under model misspecification for a family of general Bayesian parameters. In Chapter 1 we introduce the core topics of this thesis, in particular the foundations of statistical modelling, model misspecification and general Bayesian updating.
In Chapter 2 we revisit the weighted likelihood bootstrap. This method can be interpreted as sampling exactly from a Bayesian nonparametric posterior distribution, making only weak assumptions about the data-generating mechanism. The loss-likelihood bootstrap is developed as a generalisation of this idea to a wider family of parameters. By making a connection with general Bayesian updating, we provide a means of calibrating the parametric form of the general Bayesian posterior by matching asymptotic posterior information.
In Chapter 3 we present a novel framework for Bayesian nonparametric learning from Bayesian parametric models. A mixture of Dirichlet processes is well suited for incorporating information from a misspecified model into a nonparametric analysis. The properties of this method are examined, and a computationally scalable algorithm for posterior sampling, called the posterior bootstrap, is described. Extensions to the correction of approximate posterior distributions, and to more general parameters of interest, are pursued.
In Chapter 4 we explore two extensions to the work of Chapters 2 and 3. In the first, we explore an application of our nonparametric learning framework to sparse regression problems and investigate the properties of nonparametric learning under a lasso objective function. In the second we consider how we should extend the posterior bootstrap to parametric statistical models containing random effects. Both of these extensions are based on the notion of uncertainty quantification by suitably randomising an objective function.
In Chapter 5 we conclude and discuss future work.
Customer mobility and congestion in supermarkets
Keywords: supermarkets
networks
complex systems
queueing networks
human mobility

We model customer mobility and congestion in supermarkets and investigate how these two processes depend on the layout of a store. Our motivation is twofold: we seek to understand how customers move in supermarkets and how to arrange the layout of a supermarket to reduce congestion in it. Congestion affects both the shopping experience and the bottom line of supermarkets, so models that can estimate customer mobility and congestion in new store layouts are of great interest to retailers.
We use random-walk models and population-level mobility models to model customer mobility, and we use queues and queueing networks to model congestion. We represent a store as a network in which the nodes are zones in a supermarket and edges connect adjacent zones. Customers traverse the network from node to node and queue at each node. We measure congestion by the total mean queue size Q (which is equivalent to the total number of customers in a store). We are interested in how network topology (representing store layout) affects Q.
We first examine a simple model of single-source, single-sink queueing networks with unbiased random walkers. We analyse the relationship between congestion (specifically, Q) and network topology, and we describe network topologies that minimize Q. We also present efficient greedy algorithms for edge addition and deletion to reduce Q. We then consider human-mobility models and use them to estimate mobility flows between zones in a supermarket. These models have, to our knowledge, not been applied previously to problems with such small spatial scales. We applied the human-mobility models to 17 supermarkets, and we find that they can successfully estimate 65-70% of the mobility flow in a supermarket. We also find that the parameters in our models do not change markedly between different stores and different time periods of the same store. One can therefore calibrate the parameters of our models on one store and then use the models to estimate mobility flow in all other stores using only purchase data and the store layouts. Finally, we integrate the human-mobility models into a queueing-network framework to estimate congestion in supermarkets. We present a simple optimization algorithm that swaps the locations of aisles and finds store layouts with significantly smaller values of Q. In these store layouts, popular nodes are often moved from the centre of a store to the perimeter.
Our research helps improve understanding of customer mobility and congestion in supermarkets, especially the relationship between congestion and store layout. Our models and ideas are also relevant for complex systems on similar spatial scales (eg, mobility of visitors in a museum).
The role of the HIF-PHD pathway in carotid body Type I cell proliferation
Keywords: PHD2
HIF
Ventilation
hypoxia

The carotid body is an important peripheral chemoreceptor in adult mammalian physiology. A small, paired neuroendocrine tissue located at the carotid bifurcation in the neck, the carotid body is a polymodal chemoreceptor which detects fluctuations of a number of substances in arterial blood, most notably oxygen. In response to low oxygen levels (hypoxia), the Type I cells of the carotid body release neurotransmitters onto afferent nerves to stimulate a rapid adaptive hyperventilatory response. In addition to this acute response, sustained hypoxia results in a substantial increase in the size of the carotid body, known as carotid body hyperplasia. It has been proposed that this proliferative response qualifies the carotid body as a stem cell niche, and characterizing the mechanisms behind this proliferation is of significance for understanding both the specialist function of the carotid body and the wider influence of hypoxia on cellular proliferation. Previous work in this field has implicated the hypoxia-inducible factor (HIF) transcription factors and the regulatory prolyl hydroxylase family (PHD) as master regulators of the responses to hypoxia across the organism, and in the carotid body specifically.
This thesis also establishes that pseudohypoxic stimulation of the carotid body Type I cells via genetic inactivation of the HIF prolyl hydroxylase PHD2 is sufficient to drive a multilineage expansion of the carotid body. The resulting pseudohypoxic carotid bodies were grossly enlarged, highly vascular and contained multiple ultrastructural abnormalities. An exciting implication of this is that this mouse line may represent the first mouse model for carotid paraganglioma, a subtype of paraganglioma derived from the carotid body. In addition to the effects on proliferation, ultrastructural changes were observed in the signalling vesicles of the Type I cells, suggesting a functional link between the HIF-PHD pathway and the acute signalling function of the organ. Taken together, these results demonstrate an essential role for the HIF-2α-PHD2 couple in the function of Type I cells in the carotid body.
Metal-metal bonding in poly-metallic systems
Keywords: CASSCF
spectroelectrochemsitry
metal-metal bonds
density functional theory
poly-metallic

This thesis focuses on the nature of metal-metal bonding in poly-metallic systems. The electronic structures of examples of this class are studied using both density functional theory (DFT), time-dependent density functional theory (TD-DFT), periodic density functional theory and also the complete active space self-consistent-field (CASSCF) methodology. The thesis starts with a broad introduction to the chemistry of metal-metal bonded systems in chapter 1, where the focus is on the historical development of our understanding of the metal-metal bond from both experimental and theoretical perspectives. Potential applications of metal-metal bonded species are also covered. In chapter 2, a brief introduction of theoretical techniques used in this thesis is presented, covering Hartree-Fock theory, multi-configurational approaches and density functional theory, along with a discussion of basis sets. The first of the main results chapters, chapter 3, covers the electronic structure of face-shared trimetallic systems, [(PEt3)3Ru(MCl6)Ru(PEt3)3]z+, where M= Ru, Rh and Ir. Our aim here is to provide a framework for interpreting the available structural and spectroscopic evidence, and use this insight to establish how metal-metal interactions change as a function of the identity of the metal ions and also their oxidation states. Our results suggest that the switch from Ru to Rh/Ir in the central position induces a marked shift from a delocalized regime to one where unpaired electrons on the outer Ru centers only interact weakly via super exchange. The nature of the metal-metal bonding of face-shared tetra-metallic systems, [(PEt3)3Ru(Ru2Cl9)Ru(PEt3)3]1+, is the subject of chapter 4. Here we make the comparison with 'naked' [Ru2Cl9]3-, and show that whilst reduction processes are localized on the Ru2Cl9 core, oxidation takes place at the external Ru centres, leading to metal-metal bonding that extends across the entire Ru4 chain. In Chapter 5, the electronic structure of (Cp*RuCl)2(mu - Cl)2 system is discussed. This system is unique in so much as two molecules with very different Ru-Ru bond lengths co-exist in the solid-state. We have used periodic density functional theory to confirm that the crystallographic state is indeed the lowest energy one, but that relatively minor perturbations to the environment can drive transition to states where both Ru-Ru bonds are either long or short.
Computer vision and natural language processing for people with vision impairment
Keywords: canonical correlation analysis
semantic segmentation
visual question answering
generative models
natural language processing
low vision
visual dialogue
assistive technologies
vision impairment
machine learning
blindness
artificial intelligence
computer vision
accessibility
weakly supervised
sensory substitution

Globally 253 million people live with severely impaired vision. They face extensive challenges in their day-to-day lives, from independently navigating and socialising, to fine-grained tasks like reading, and identifying and interacting with objects. Assistive tools have been developed to ease these challenges, ranging from the white cane to talking wearables, however, most remain simplistic, doing little in the way of parsing and understanding the dynamic, 3D world required for safe and easy interaction. Rapid advances in machine learning, computer vision and natural language processing, however, coupled with the miniaturisation of electronics and proliferation of mobile devices and wearables, are redefining the landscape of assistive technologies for people with vision impairment.
This thesis takes concrete steps toward the goal of data-driven assistive technologies by exploring methods for i) understanding visual scenes, ii) relaying this information to visually impaired (VI) users, and iii) evaluating models for relaying information through natural language. In the first direction, we develop a state-of-the-art weakly-supervised semantic segmentation method which segments objects using only classification labels. These labels can easily be collected from vi users as they interact with objects in the real-world. In the second, we develop two methods for relaying information about the environment. We do this by i) creating spatial audio soundscapes of 3D scenes, and ii) allowing users to directly ask questions about their visual environment, which the system then answers. We validate the first on human participants in virtual reality environments, and the second using quantitative metrics on experimental datasets. In the third direction we investigate a widely-used dataset for a sequential visual question-answering task and find that it contains exploitable biases which are exacerbated by poor evaluation metrics. We then propose a better method for evaluating, and quantifying performance on this task. In the future data-driven assistive technologies hold much promise for people with vision impairment. Efforts must, however, consider how well data-driven models port to real-world scenarios, where i) the incoming data will be considerably different from that in established visual perception datasets, and ii) the portability constraints of mobile devices are much more stringent.
Experiencing development on China’s frontier: the Nuosu’s bridewealth
Keywords: developmentalism
Nuosu
Chinese ethnic minorities
bridewealth
value

The thesis investigates the “problematic” inflation in bridewealth among the Nuosu people in contemporary Liangshan, Southwest China, to elucidate how ethnic minorities engaged with various state-steered development projects. The study treats “development” as a historical process, in which the practice of bridewealth has been associated with the ethnicity of the Nuosu, and the inflation in bridewealth has been attributed to the “backwardness” of the Nuosu culture both in political discourses and policy-making of the state. The thesis discusses, through ethnographic materials, how the Nuosu of various statuses indigenise the “humiliation” inflicted on them by state development. The historical perspective and ethnographic method serve to show empowerment of the Nuosu as reflectors of their society. Nuosu on-going and dynamic negotiation and engagement with state definitions of ethnicity and legitimacy has thus led to the reification of the state as an interlocutor at the most local level and in core events of Nuosu’s daily life, importantly the practice of bridewealth.
The thesis reveals “the variants of development” rooted in the understanding/misunderstanding of planned templates for development. The variants are manifested by the multiplicity of voices and the creativities found in the narrations and implementation of development. By engaging with anthropological debates on the themes of “value” and “the anthropology of the good”, the thesis demonstrates how the shift in the value attached to the Nuosu brides transvalues the external environment such as manifested in state investigations, regulations, and legislation. More importantly, the humiliation inflicted on Nuosu culture in the process of promoting development has not resulted in the depreciation of the value that define being a “real” Nuosu. Instead, the practice of bridewealth is informed by Nuosu collective values which simultaneously are creating values. The inflation in bridewealth highlights and transvalues the yearnings and desires of the Nuosu in their most exalted form, leading to a core insight of the thesis that values associated with a “real” Nuosu identity acquired their most forceful impact in the Nuosu encounter with state developmentalism.
ATP delivery rates in myocardial hypertrophy
Keywords: mitral regurgitation
saturation transfer
creatine kinase
aortic stenosis
phosphotransfer
cardiac metabolism

This thesis aims to better understand the metabolic dimension of cardiac adaptation to increased work by studying the creatine kinase (CK) system in participants with pathological hypertrophy secondary to severe aortic stenosis with preserved ejection fraction (SevAS-pEF) or secondary to severe primary mitral regurgitation (MR), participants with hearts adapted to exercise training, and participants with no hypertrophy (NH). It also aims to understand why some hearts transition to failure in the presence of pressure overload, by studying a group with severe aortic stenosis with reduced ejection fraction (SevAS-rEF).
Broadly speaking there are two pathways for ATP delivery from sites of production in mitochrondria to sites of use at the myofibrils: facilitated diffusion by the CK system and simple diffusion. This thesis aims to investigate both. Closely related to this, CK also has roles in the temporal buffering of adenine nucleotides and the control of respiratory flux over varying work rates, so more broadly represents a kind of metabolic reserve. CK activity can be assessed on freeze-and-extract biochemical assay.
Using 31phosphorus-magnetic resonance spectroscopy (MRS) saturation transfer to estimate the CK rate constant (kf) is the first step toward estimates of in vivo flux. Over 60 intra-operative left ventricular (LV) biopsies in participants with pre-operative 31P-MRS are collected to validate the novel TRiST sequence against biochemically-assessed maximum CK rate. Ch. 3 describes non-invasive and invasive predictors of CK total activity and derives a three-variable linear regression model in 37 triplicate datasets to predict CK total activity from total creatine, kf and LV end-systolic volume index.
Ch. 4 studies invasive and non-invasive measures of the CK system in participants with sevAS-pEF, sevAS-rEF, and NH. The chapter argues for the assessment of metabolic reserve as a way of identifying – and explaining – the recently described subset of patients whose ventricles deteriorate sooner in the face of pressure overload. A stepwise fall in median CK total activity is found when arranging groups in order of increasing LV mass index. Non-invasive measures are also assessed in participants with moderate AS, healthy volunteers, and sevAS-pEF participants late post-operatively.
The CK system is then studied in participants with severe primary MR and preserved systolic function pre- and post-operatively (Ch. 5), and in participants with physiological hypertrophy or normal, non-trained, hearts at rest and during dobutamine stress (Ch. 6). Ch. 7 relates CK activity with ATP diffusion distance using 3D models built from tomographic stacks of electron microscopy images in a subset of LV biopsies.
Who will govern artificial intelligence? Learning from the history of strategic politics in emerging technologies
Keywords: Strategic technologies
General purpose technologies
Technology governance

Artificial intelligence (AI) is a strategic general purpose technology (GPT) with the potential to deliver vast economic value and substantially affect national security. The central claim motivating this work is that the development of a strategic GPT follows a distinct pattern of politics. By modelling this pattern, we can make predictions about how the politics of AI will unfold.
The proposed model follows a life cycle of a strategic GPT. It focuses on three actors – the state, firms, and researchers. Each actor is defined by their goals, resources and constraints. The model analyses the relationships between these actors – specifically, the synergies and conflicts that emerge between them as their goals, resources, and constraints interact.
Case studies of strategic GPTs developed in the U.S. – specifically aerospace technology, biotechnology, and cryptography – show that the model captures much of history accurately. When applied to AI, the model also does well to capture political dynamics to date and motivates predictions about how we could expect the politics of AI to unfold. For example, I predict that AI firms will be increasingly constrained by the legislative environment, and more pressured to serve national defense and security interests. Some will be caught in the cross-hairs of public critique and researcher push back; some, however, will willingly sell AI technologies to the state with little friction. Further, I predict that the political influence of researchers will shrink, going against what some may view as a rise in researcher influence given recent events of employee backlash in AI firms. In turn, the inclination and capacity for the state to exert control over AI’s development and proliferation will likely grow, exercised via tools such as export controls.
Artificial intelligence is going to matter greatly, and indeed, already does. It matters, then, that we understand the politics that surrounds it, and that we ultimately lay the groundwork for the governance of a technology that is poised to be transformative.