VictorJuiz/thesis huggingface dataset:
Market intermediation: information, computation, and incentives

Auctions are a major field of interest in game theory and in the wider mi- croeconomics area, reflected by recognitions such as Nobel prizes to William Vickrey and Paul Milgrom. The algorithmic game theory literature too pro- vides discussion of a wide range of different auction settings. But real-life markets are rarely comprised of a single monopolist facing buyers without alternative. We therefore explore market intermediation, in which we aim to match buyers and sellers to achieve some objective. While auctions have been well-explored in manifold variations, intermediation has received less attention in the literature.
We aim to move beyond the independent, single-unit case and explore the limits of what can be achieved in more complex scenarios. In the first part, we look at a correlated-priors setting. We show that the revenue-optimal mechanism for this can be computed using a polynomial-time algorithm for one buyer and one seller. For two or more buyers we show that this problem is NP-hard, in contrast, but that truthful-in-expectation mechanisms can be computed using an LP in polynomial time for fixed number of buyers and sellers. In this setting we further discuss how market intermediation relates to classical auctions, as well as reverse auctions. Further motivating our results, we show that our discussion of market intermediation can lead back to useful results for both of these settings, giving an improved algorithm for the optimal two-bidder auction, and showing for the first time that a reverse auction behaves differently than an auction.
In the second part, we consider an online intermediation setting, in which the market maker encounters an unknown sequence of buyers and sellers one at a time, with knowledge of their independent priors. We explore this from the point of view of online algorithms and competitive analysis, comparing against an offline adversary who knows the buyer-seller sequence in advance. For the general case, we show that the competitive ratio of the intermediary’s revenue grows as the square root of the number of buyers and sellers. In contrast, we consider two settings with natural restrictions; one in which the sequence is balanced, and one in which there is an upper limit on the number of items the intermediary is allowed to hold at any one time. For both these settings we show that the competitive ratio is constant.
Finally, in the third part we explore multi-unit intermediation. In this, we consider one seller and one buyer each having concave valuation of a number of items. The intermediary’s aim will be to maximise welfare, while maintaining budget balance. This setting has been explored for the single- item case, along with simple reductions for divisible goods to that case. We will give a strong characterisation result as well as approximation guarantees for the multi-unit case.

Advisor: Goldberg, P
Koutsoupias, E
Multi-mass imaging in chemical reaction dynamics

The work described in this thesis illustrates the application of multi-mass velocity-map imaging in the investigation of molecular fragmentation dynamics. Results from three experiments, focussing on three types of fragmentation processes, are reported. Firstly, a photofragmentation and photoionization study of niobium oxide (NbO) is presented. Analysis of the recorded velocity-map images yields refined values for the dissociation energies of NbO and NbO+, which are found to be 60,650±124 cm−1 and 57,414 ± 124 cm−1, respectively. In addition, the first steps towards the study of charged metal-ligand clusters are outlined using the example of the photofragmentation of the VCO2+ complex.
In Chapter 3, the UV-induced photofragmentation dynamics of the CH2BrI molecule are studied in a time-resolved UV-pump XUV-probe experiment. While the findings are largely consistent with previous studies on this system, evidence for charge transfer processes between the XUV ionized halogen photoproducts and neutral rotationally excited CH2Br fragments are found.
Finally, Chapter 4 presents an experimental study of the dissociative electron ionization of CF3I. Following the ionization step, dissociation of singly-charged parent ions proceeds via either the C-I bond or C-F bond breaking with very different dynamics. A mixture of statistical′anddirect' bond breaking dynamics is observed, and can be rationalized by comparison with photoionization studies. Evidence for the fragmentation of doubly and triply charged ions is also found, with these processes apparently proceeding via a two-body Coulomb explosion followed by further fragmentation of the molecular product ion.

Keywords: Electron ionization
Laser spectroscopy
PImMS
Molecular beams
Velocity-map imaging
Multi-mass imaging
Mass spectrometry
Ion imaging
Advisor: Vallance, C
Brouard, M
Mackenzie, S
Novel fluorination methodology through computational insight – tuning fluoride through hydrogen bonding

Even though carbon-fluorine bonds are uncommon in nature, fluorination of organic molecules is well-known to induce desirable biological properties. Methods for fluorination are therefore highly sought after; however, one of the most convenient sources of fluorine, inorganic fluoride salts, are inconvenient reagents. Inspired by the fluorinase enzyme’s binding of fluoride through hydrogen bonding, this work describes the computational investigation of the effects of hydrogen bonding on fluoride reactivity and selectivity, in collaboration with experimental chemistry, to develop novel catalytic methods for asymmetric fluorination of organic molecules with simple fluoride reagents.
Chapter 1 summarizes the current state of the art for using fluoride as a reagent for fluorination of organic molecules. Computational methods and challenges in modeling such systems are also described. Chapter 2 describes the study and rationalization of experimental data on the effect of hydrogen bond donor strength on the reactivity and selectivity of urea-fluoride complexes as reagents in a model SN2 vs E2 reaction with primary bromide substrate. This chapter also describes benchmarking of computational methods for accurate description of fluoride. Chapter 3 describes the development of hydrogen bonding phase-transfer catalysis (HB PTC) and its application to asymmetric fluorination with group 1 metal fluoride salts and chiral urea organocatalyst, including mechanistic study and computationally guided catalyst design. Chapter 4 describes the application of HB PTC to asymmetric desymmetrization of aziridinium ions. Computation yields insight into the origins of enantioselectivity and the activation of potassium fluoride as fluoride source. The final chapter discusses the computational insight into the effects of hydrogen bonding on fluoride, including consequences for enantioselectivity and catalytic kinetics.

Advisor: Gouverneur, V
Paton, R
Investigating the pathogenesis of congenital insensitivity to pain using gene-editing in an in vitro model

The voltage gated sodium channel Nav1.7 is a key component of the mammalian nociceptive system. Homozygous loss of function mutations in SCN9A, the gene that encodes Nav1.7, cause congenital insensitivity to pain (CIP) in humans. Affected individuals are unable to perceive pain in response to any noxious stimulus, be it mechanical, chemical or thermal in form. Rare Mendelian disorders such as CIP can offer insight into the complexities of common, polygenic conditions such as chronic pain. As a result, the channel has attracted significant interest as a therapeutic and research target. However, a lack of primary material suitable for studying human Nav1.7 has hindered the characterisation of its function and cellular localisation. Here, we have developed an in vitro human model through the use of gene-editing tools suitable for the experimental interrogation of hNav1.7. Using CRISPR/Cas9, we genetically tag Nav1.7 and reveal the channel is robustly expressed at the soma cell surface, axons and enriched in the terminals of iPSC-nociceptors. Further, through the use of both novel gene-edited and CIP derived lines we demonstrate the channel has a key role in regulating neuronal excitability. Together, our findings provide mechanistic insight into the pathogenesis of congenital insensitivity to pain and contribute, more broadly, to our understanding of human nociceptive signalling.

Advisor: Bennett, D
The tunebooks of J. B. Malchair, Oxford, c.1760-1812

From at least 1760, when he moved to Oxford, the German-born musician and artist, John Malchair (1730-1812), collected tunes of various nations. His sources ranged from printed books to acquaintances at the University and even, on one occasion, the whistling of a man in the street. Over the next thirty-five years, Malchair assembled four volumes of tunes, only the third and fourth of which are extant. Malchair’s third tunebook is titled ‘Vol. 3d: The Third Collection of Tunes’; his fourth tunebook is called ‘The Arrangement’, and in it he ‘arranged’ about 500 tunes already known to him into three categories: Welsh, Irish and Scottish. This thesis will describe Malchair’s collecting habits in the context of collecting in Britain in the eighteenth century, and the publication of collections of tunes, as well as providing a more detailed focus on these activities in England.
Malchair created a title page for ‘English Tunes’ within ‘The Arrangement’ but added no music to this section of the manuscript, yet there are several ‘English’ tunes that have been included in other sections. In addition, there are a number of apparent contradictions, such as where the same tune is included under two different national headings. I will explore a range of examples in order to explain Malchair’s scheme of national categorisation, and consider Malchair in relation to those among his contemporaries and near-contemporaries who also addressed questions of national categorisation in music.
Malchair’s tunebooks are different from most others, while also growing out of a shared pre-existing and widespread culture of tunebook-keeping and personal music-collecting. I will argue that this difference stemmed from the fact that his tunebooks were not for personal music-making, as was usually the case, but instead formed a ‘collection’. I will posit two hypotheses: first, that Malchair’s purpose in collecting was to compare tunes as he found them (rather than editing them) and thereby to identify the ‘best’ version; and, second, that Malchair’s aim in categorising his tunes was to demonstrate the characteristic music of each nation, and that in categorising he was primarily concerned not with geographical origins, but rather with national style.

Advisor: Aspden, S
Observations for practical Fermi–Pasta–Ulam–Tsingou systems

Nonlinear dynamics is a field that has been widely studied by mathematicians and scientists. However, engineers are yet to exploit the full potential of nonlinearity in coupled systems despite the majority of real physical systems being inherently nonlinear. Although a vast array of results has been generated from simulations, only a small number of physical systems have been investigated.
In a 1955 report, Fermi, Pasta, Ulam, and Tsingou reported recurrence of energy between modes in a simple mass-spring system containing a nonlinear coupling term. Extensive numerical simulations of the FPUT system have followed this discovery. However, minimal evidence of FPUT recurrence has been observed in physical systems.
This may be due to the effect of ‘real-world’ imperfections on the ideal systems used in the simulations. Variations between system components due to manufacturing tolerances and energy losses through damping are present in most physical systems. By understanding the effects of these imperfections, it may be possible to apply the results of the simulations to physical systems.
The effects of tolerance and damping on recurrence were studied using a series of simulations. The results demonstrate that such imperfections degrade the observation of recurrence, often leading to complete loss in moderately sized arrays. These simulations enabled the identification of a series of conditions under which a practical system might display recurrence. Tight tolerances, low damping, small array size and moderately weak coupling strengths are required.
An electronic amplifier circuit was designed to meet these constraints. Preliminary testing of this electronic system has provided early verification of the simulation results. FPUT recurrence was observed a system with four elements. These results suggest that without considering tolerances in real systems, the applicability of the results from simulations to physical systems may be limited.

Advisor: Collins, S
Choubey, B
"Der Zauberberg" and the pleasures of immersive reading

This is the first study of "Der Zauberberg" written from the perspective of its non-academic readers. It will be of interest to scholars of Thomas Mann, transnational German studies, comparative literature, and reception studies. Starting from the observation that literary scholarship almost never engages with the experience of non-academic readers, I argue that this is a serious limitation, since our very rationale for studying books is that they belong to human culture and matter to their readers. This is a particularly pressing problem for the study of "Der Zauberberg" because the novel portrays Hans Castorp’s gradual immersion in culture: in other words, it thematizes the very process of reading, reception, and the value and relevance of culture. In this study, I discuss hundreds of records of reading experiences – preserved in parentheses and asides and between the lines of traditional academic studies, on Internet fora and blogs, in reviews, essays and memoirs, marketing brochures from Davos and advertizing copy used to sell the novel, Mann’s fan mail and his replies to it, and in books and films, whether popular, famous or half-forgotten. The reading records that I have brought together span the century since the novel’s publication, as well as numerous languages and several continents, and testify to an energetic confrontation with "Der Zauberberg" outside the ivory tower of academia. Using the common metaphor of immersion in a book, I discuss different examples of how and why non-academic readers have engaged with the novel and what it has meant to them, and what academic readers have missed by not attending to this wealth of untapped material. Through case studies of different responses to "Der Zauberberg", I ask what it means to interact with culture, and argue that this is precisely what the novel is all about.

Keywords: German literature
Thomas Mann
Reception
Der Zauberberg
The Magic Mountain
Comparative Literature
Advisor: Morgan, B
Constructions in stable commutator length and bounded cohomology

The bounded cohomology of a group G with coefficients in a normed G-module V was first systematically studied by Gromov in 1982 in his seminal paper [Gro82] in connection to the minimal volume of manifolds. Since then it has sparked much research in Geometric Group Theory. However, it is notoriously hard to explicitly compute bounded cohomology, even for the most basic groups: There is no finitely generated group G for which the full bounded cohomology with real coefficients is known except where it is known to vanish in all degrees (see [Mon06]). In this thesis we discuss several new constructions for classses in bounded cohomology.
There is a well-known interpretation of ordinary group cohomology in degrees 2 and 3 in terms of group extensions. We establish an analogous interpretation in the context of bounded cohomology. This involves certain maps between arbitrary groups called quasihomomorphisms, which were defined and studied by Fujiwara and Kapovich in [FK16].
A key open problem is to compute the full bounded cohomology of a non-abelian free group F with trivial real coefficients. It is known that the bounded cohomology in dimension n is trivial for n = 1 and infinite dimensional for n = 2, 3, but essentially nothing is known about for n ≥ 4. For n = 4, one may construct classes by taking the cup product between two 2-classes, but it is possible that all such cup-products are trivial. We show that all such cup-products do indeed vanish if both classes are induced by the quasimorphisms of Brooks or Rolli.

Keywords: Bounded Cohomology
Stable Commutator Length
Advisor: Bridson, M
Toll links metabolism and microbiota in the Drosophila intestine

Peptidoglycan recognition protein SA (PGRP-SA) is an extracellular recognition protein, which interacts with the peptidoglycan of Gram-positive bacteria and activates the Toll signalling pathway. While many studies have described the interaction of PGRP-SA with pathogenic bacteria, studies on its response to commensal bacteria is lacking. Using Drosophila melanogaster as a model organism, we demonstrate the relationship between PGRP-SA with the indigenous gut microbiota, and how the activity of mTOR influences this relationship. Our results reveal that PGRP-SA is essential to maintain microbial load and retain Lactobacillaceae in young flies. Moreover, inhibition of the activity of mTOR restores the microbiota of PGRP-SA mutant seml flies in a density dependent manner. Translational regulation factor, 4E-BP, whose levels are dictated by both Toll and mTOR pathway of the host, mediates this host-microbiome interaction. Our results give an insight into how host factors maintain indigenous microbiota in a healthy gut. This can help us better understand the genetic basis of variation in the composition of gut bacteria, and assist in developing measures to tackle microbiota induced disorders in the future.

Keywords: Toll pathway
4E-BP
Lactobacillaceae
Gut microbiota
Rapamycin
mTOR pathway
Advisor: Ligoxygakis, P
Why does God save the king?

Inspired by the outcome of the 2010 Arab uprisings, this project explores the causal mechanisms behind regime survival in the monarchies of the Middle East and North Africa (MENA). It is motivated by the following research question: How do Arab monarchies survive active opposition?
To answer this question, this study develops a theory about successful regime behavior that leads to survival. This theory highlights how active opposition impacts the process that leads to regime survival, and how survival-seeking regime behavior in turn affects immediate as well as future opposition. It argues that authoritarian monarchs survive by using a specific toolkit to contain (rather than exacerbate) threats. This toolkit consists of various combinations of strategies which rulers choose consistently depending on the level of threat which they face. The latter is determined by the goals and motivations of the opposition, the evolving interrelationship between the regime and different opposition actors, and various exogenous factors.
Methodologically, this project is characterized by a mixed methods triangulation approach which analyzes both quantitative and qualitative data separately before converging the results for interpretation. The author’s analysis of a wider scope of different but complementary data- from in-depth interviews, archival research, primary sources, trends and datasets- allows her to advance well-substantiated conclusions. Moreover, this study is constructed around a three-part, in-depth explanatory case-study which follows a micro-level approach to within-country and cross-country analysis. Its main theory is built through a fine-grained analysis of Morocco and Oman, confirmed through a cross-country analysis of the remaining six Arab monarchies, and further developed through a study of negative cases such as Iran’s Pahlavi monarchy and Gaddafi’s Libya.
This dissertation makes several important theoretical and empirical contributions to the fields of Comparative and Middle East politics, and its main argument presents a novel and comprehensive explanation about authoritarian persistence.

Keywords: Social Movements
Protests
Regime Survival
Subsidies
Oil
Opposition
Monarchy
Authoritarianism
Advisor: Bermeo, N
Non-contact vital sign monitoring of pre-term infants

Non-contact vital sign monitoring using video cameras enables the measurement of heart rate and respiratory rate to be performed without sensors attached to the skin of the patient. This provides advantages in terms of patient comfort and the management of skin irritation and infection. However, the use of non-contact technologies in the clinic presents several challenges such as variations in human skin colour, changes in lighting conditions, the detection of the presence of a patient in the video frame and the selection of suitable regions of interests (ROIs) from which vital signs can be estimated.
This thesis proposes a framework for the accurate and continuous measurement of heart rate and respiratory rate in pre-term infants in a real-world hospital environment. The framework has been developed and validated on the data obtained from a clinical study of pre-term infants hospitalised in the high-dependency area of the neonatal intensive care unit (NICU) of the John Radcliffe Hospital in Oxford. The study involved the recording of videos and reference vital signs for 90 sessions during daytime from 30 pre-term infants, comprising a total recording time of 426.6 hours. The dataset provided a wide range of vital sign values for developing and validating the framework.
Multi-task deep learning algorithms were developed so that vital-sign estimation could be performed only when the infant was present in front of the video camera and no clinical interventions were undertaken. The algorithms are able to deal with different skin tones, lighting condition changes and variable body postures.
Heart rate is estimated from the photoplethysmographic imaging (PPGi) signal derived from subtle changes in the colour of the skin areas. Respiratory rate is estimated using data fusion from the PPGi signals along with the shape and morphological properties of the skin areas. Signal quality assessment algorithms are developed for both heart rate and respiratory rate to discriminate between clinically acceptable and noisy signals. In a test set, the mean absolute error between the reference and camera-derived heart rates is 2.3 beats/min for over 76% of the time for which the reference and camera data are valid. The mean absolute error between the reference and camera-derived respiratory rate is 3.6 breaths/min for over 78% of the time. Most of the time periods during which the video camera cannot provide estimates of heart rate and respiratory rate are lower than 30 seconds.
This thesis further investigated the feasibility of using non-contact algorithms to estimate heart rate and respiratory rate during a painful clinical procedure, a heel prick for withdrawing blood for blood gas analysis. Adaptation of the algorithms enables physiological indicators of pain to be derived from the analysis of the video camera data.

Keywords: Camera
Non-contact monitoring
Respiratory rate
Heart rate
Photoplethysmography
Vital signs
Advisor: Tarassenko, L
Montoya, M