VictorJuiz/thesis huggingface dataset:
Online algorithms for markets
Keywords: Online Algorithms
Cryptocurrencies
Algorithmic Game Theory

The thesis consists of two parts, both dealing with issues of uncertainty and incentives in markets. In the first part we examine the online properties of markets. In most of the Mechanism Design literature, markets are studied under the assumption that all participants are present at the same time and can seamlessly interact with each other. This may not always be the case in practice. We consider markets where buyers and sellers appear in sequence, one after another, without overlapping and it is the duty of an intermediary to coordinate with them. We take the role of that intermediary and our goal is redistribute items among them to maximise certain objectives, namely the profit, social welfare or gain from trade. We focus on posted price mechanisms, which are robust and truthful. There are two natural, complementary variants of the order of arrival of the agents. In the first case, an adversary dictates their order, but the intermediary has prior, distributional information about their valuations, similar to the prophet inequality setting. In the second, the adversary selects their valuations but their order is a uniformly random permutation. We obtain asymptotically tight worst-case guarantees for both cases, under a competitive analysis benchmark.
In the second part, we study the strategic implications that arise from adding one extra option to the miners participating in the bitcoin proto- col. We propose that when adding a block, miners also have the ability to pay forward an amount to be collected by the first miner who successfully extends their branch, giving them the power to influence the incentives for mining. We formulate a stochastic game for the study of such incentives and show that with this added option, smaller miners can guarantee that the best response of even substantially more powerful miners is to follow the expected behavior intended by the protocol designer. Moreover, pay-forward can be used to alleviate the predicted instability when block rewards are small compared with respect to transaction fees, by smoothing out the variability of the rewards collected from transaction fees.
Beauty and the Gods in Archaic Greece
Keywords: Beauty
Archaic Greece
Greek Gods

This thesis is about the relationship between the beautiful and the divine in Archaic Greece. By examining the literary, epigraphic and archaeological records, it seeks to understand how ideas, representations and experiences of beauty informed Greek relations with the gods in the Archaic period (c.750-480 BCE). One aim of the thesis is to elucidate the significance of beauty for Archaic conceptions of the gods. The first chapter explores the representation of the beautiful and the divine in Archaic epic, especially Hesiod and Homer, who profoundly affected attitudes to the gods from the Archaic period to late antiquity. How conceptions of beauty and the gods oriented worshippers’ values, actions and the character of their experiences is the focus of the remaining chapters. The second core aim of the thesis, therefore, is to explore the significance of beauty for different forms and contexts of divine worship in Archaic Greece: from musical performances for the gods in chapter two, to developments in sacred architecture in chapter three, to the practice of giving objects to the gods in chapter four. As chapters three and four highlight, the material culture of Greek sanctuaries changed dramatically between the late eighth and early fifth centuries BCE. A central argument of the thesis is that the value and experience of beauty were integral to these changes, which had enduring consequences. Despite its under-representation in scholarship on ancient aesthetics, the Archaic period witnessed a transformation in Greek culture which was pivotal for the religious and aesthetic values, expectations and experiences of later generations of classical antiquity and beyond.
Therapeutic targeting of histone H3 lysine 36 trimethylation-deficient cancers
Keywords: Drug discovery
Epigenetics
Synthetic lethality

Histone modifications play diverse and essential roles in the maintenance of genome integrity, as evidenced by the frequency at which different histone marks are dysregulated during tumourigenesis. The trimethylation of histone H3 at lysine 36 (H3K36me3) and SETD2, the enzyme solely responsible for this histone mark, are important in many cellular processes and have been reported to be lost or mutated in cancers. Targeting cells that are deficient in H3K36me3 or SETD2 is therefore an attractive therapeutic strategy for specifically killing tumour cells with minimal effect on normal tissue using the concept of synthetic lethality.
Using a previously reported synthetic lethal interaction between SETD2 and the WEE1 kinase as a starting point, a high-throughput small-molecule compound screen was performed in cells in which SETD2 had been deleted using CRISPR-Cas9 technology. The aim of this screen was to identify two categories of hits: (1) those that enhance the SETD2-WEE1 synthetic lethality (synergy hits) and (2) those that target SETD2-CRISPR cells on their own (novel synthetic lethality hits).
Analysis of the synergy hits focused on histone deacetylases (HDACs), which revealed that the Class I HDACs HDAC1 and HDAC2 had differential effects on the SETD2-WEE1 synthetic lethality. Furthermore, depletion of both HDACs individually led to a significant loss of viability specifically in SETD2-CRISPR cells. The results suggest a putative synthetic lethality between SETD2 and HDAC2 that bears certain similarities to the relationship between SETD2 and WEE1.
The most potent among the novel synthetic lethality hits was a compound called RITA, which demonstrated the ability to target SETD2 deficiency in the form of CRISPR knockout, siRNA knockdown, and naturally occurring mutations. This was accompanied by a striking upregulation and activation of the p53 tumour suppressor, activation of the DNA damage response, cell cycle arrest, and apoptosis. These phenotypes were further associated with increased levels of replication stress markers and reduced replication fork velocity. The potential mechanism of action of this compound was investigated via a number of strategies based on current knowledge of SETD2 and RITA, as well as more exploratory approaches. Overall, the data indicate that perturbations in the G1/S transition and replication stress play key roles in mediating RITA’s cytotoxicity in the context of SETD2 loss.
Human genetic variation and the dispersal of Bantu-speaking populations
Keywords: Human genetic variation
Africa
Admixture
Bantu-speaking populations

The expansion of Bantu-speaking agropastoralist populations had a significant impact on the genetic, linguistic, and cultural variation of sub-Saharan Africa. Bantu languages originated in an area close to the present-day border between Cameroon and Nigeria not earlier than 5000 years ago. From their homeland, these languages spread south and east through most of sub-Saharan Africa becoming by far the largest African linguistic family. Even though it is generally accepted that this dispersal was the result of the migration of people, there are still many unanswered questions about the dynamics of this process. The demic consequences of this dispersal are reflected in the relatively high genetic homogeneity observed across most of sub-Saharan Africa populations but its implications on the genetic diversity of the continent are not fully appreciated yet. Incorporating African populations’ genome-wide data available from Prof. Capelli’s research group with previously published data, this thesis addresses and tries to answer some of the questions related to the genetic impact of this dispersal.
I start by addressing the process of admixture between the migrating Bantu speakers and previous inhabitants in south-east Africa.
Rejecting the hypothesis of a potentially pre-Bantu component found in south-east African Bantu-speaking populations as the result of extensive gene flow, I highlight the importance of the demographic dynamics associated with the Bantu dispersal in shaping the genetic diversity of these communities. I then focus on the analysis of the genetic variation observed in sub-Saharan Niger-Congo populations, highlighting the impact of admixture events and the existence of population structure within Bantu speakers, often considered as a genetically homogeneous group. Lastly, I attempt to mask the admixture events I found and reconcile genetics, geography, and linguistics in order to reconstruct the relationships among the Bantu-speaking populations across the continent.
Overall, my results emphasize the diversity observed in Bantu-speaking populations and the impact their rapid dispersal and contact with other communities had on the genetic variation they show.
The impact of everyday violence on identity: an experimental study in Nigeria
Keywords: Intergroup Relations
Nigeria
Conflict
Identity
Africa
Violence

“Everyday” violence, such as robbery, burglary, or interpersonal assault, is endemic throughout much of the developing world, yet there has been relatively little research about its effects on social identity and intergroup relations. Using original data collected from an experiment embedded in a survey of over 1,000 people in Lagos, Nigeria, I empirically assess the impact of the acute threat of everyday violence, as well as actual victimization, on social identity, trust, and attitudes about violence and politics.
I find that exposure to everyday violence significantly impacts identity – and that its effects vary considerably depending on whether the individual was “merely” threatened by violence or actually experienced it firsthand. The fear induced by an acute threat of everyday violence is broadly identity-affirming, increasing evaluations of and warmth toward the primary in-group and depressing trust in and attitudes toward the out-group. Actual victimization, however, has the opposite effect, leading to a greater openness toward and trust in the primary out-group. Neither threat nor victimization significantly impacts attitudes about politics or the future use of violence.
Drawing on over 70 interviews with violence-affected-Lagosians, I argue that the way expectations about one’s security and community are defied and then rebuilt may account for this effect. Specifically, I point to three contributing factors: 1) disappointment in the apathetic in-group response; 2) “empathy-born-of-violence;” and 3) positive religious coping. These dynamics play out over time and are largely dependent on interactions with others; in this sense, one’s social environment may significantly shape whether victimization leads to openness to others and to what extent.
This research demonstrates, among other things, the profound and diverse ways in which exposure to everyday violence affects identity, and the importance of incorporating the study of everyday violence into research agendas about the dynamics of identity and conflict.
Studies of the Martian atmospheric boundary layer and global circulation from combined use of spacecraft data and numerical circulation models
Keywords: Mars Modelling
Mesoscale Modelling
Singular Spectrum Analysis
General Circluation Modelling
Data Assimilation
"Regional" Reanalysis
Curiosity REMS
Mars Climate Sounder
Spectral Energy Budget

In this thesis, the near-surface environment on Mars is studied in connection to the general atmospheric circulation. Well-established methods for modelling Earth's atmosphere were invoked, such as embedding a regional mesoscale model into a global atmospheric circulation model, and driving the atmospheric states from the global model, by assimilation of orbital spacecraft data. Embedding a regional model inside a global one for Mars is innovative. But the novelty of our work comes with the assimilation of spacecraft data into such an assembly of numerical models, to produce a regional (GCM+mesoscale model) reanalysis. This achievement is unique in the studies of the Martian atmosphere. However, performing this for the atmosphere of another Solar System planet, came with a collection of challenges. We first proved the viability of our terrestrial model configuration for Mars' atmosphere, by quantifying the direction of energy transfer (potential and kinetic) between scales from both free-running simulations and assimilated reanalyses. We thus produced the first systematic study of the spectral energy budget of the Martian atmosphere, and concluded that energy flows from large scales to small scales. This can be interpreted as suggesting that information flow also goes from large to small scales, to justify using unidirectional information flow from global to embedded model via boundary conditions. Moreover, we discovered that Mars is missing an enstrophy-dominated energy inertial range (i.e. the k-3 range in kinetic energy) that is present in Earth's spectral energetics.
The embedded simulations were carried out for 4 typical Martian seasons around Gale Crater, at a resolution of 80 × 80 × 60 grid-boxes of 5km side-lengths, covering a 400km × 400km region surrounding the crater. Ulteriorly, the assimilated analysis was interpolated to the location of the Curiosity rover (situated in the crater floor) for comparison with in situ measurements. Different methods of decomposing the measured variability into various time-dependent components were employed. Given that atmospheric tides are directly forced in models and reality, the correlations from the diurnal and semidiurnal atmospheric tides show almost perfect matching between our analysis and observations. The differences come from uncorrelative effects added by the crater topography and incorrect atmospheric dust and aerosol loading in the models. We finalized our pursuit by explaining both datasets (model and observations) from the superposition of correlations. We concluded that atmospheric dust and aerosol loading is responsible for the underlying shape in the data, with perturbations from superimposing the local meteorology. The tidal components that are not well-matched are important because they can lead to improved models and/or analyses.
Using routinely collected data to estimate postoperative complication rates, temporal trends, and geographical variation in Dupuytren's disease surgical management in England
Keywords: Complications
Temporal trends
Dupuytren's
Hospital Episode Statistics (HES)
Geographical variation

Introduction: Dupuytren's disease (DD) is a common fibro-proliferative condition of the hand and it is usually treated surgically. The primary aim of this thesis was to evaluate DD surgical management in terms of patient characteristics, risk of postoperative complications and reoperation, temporal trend and geographical variation in England. Secondary aim was to investigate the association between DD and non-genetic factors. Methods: A longitudinal population-based cohort study was conducted using Hospital Episode Statistics database. Cumulative incidence and self-controlled case series methods were used to investigate postoperative complications. Directly standardised rates were calculated to evaluate temporal trends and geographical variation of primary Dupuytren’s disease surgery. To investigate the association between DD and non-genetic factors a systematic review was undertaken. Results: Between 1 April 2007 and 31st March 2017, 158,119 DD operative procedures were performed in 121,488 adult patients in England. DD surgery was most commonly performed in male, elderly, white patients living in less financially deprived areas and few comorbidities. Most operations performed were primary limited fasciectomy (LF). There was a significant incidence of local and serious systemic complications following DD surgery. The rate of reoperation was highest after primary percutaneous needle fasciotomy compared to primary LF or dermofasciectomy. There was an overall increasing trend and striking variation in the rates of primary DD surgery in England. A strong association was found between DD and advanced age, male gender, family history of DD, diabetes, heavy alcohol drinking, cigarette smoking and manual work exposure. Conclusions: The study findings have significant clinical importance as they helps to better understand DD surgical management.
Redistributive authoritarianism: land reform and regime durability in the Middle East
Keywords: leader tenure
land reform

A growing literature on land reform under autocracy shows that leaders often use the expropriation and redistribution to disempower incumbent elites and to signal a credible commitment to potential coalition members. Although these strategies have been found to extend leader tenure in Latin America (Albertus and Menaldo, 2012), these patterns have yet to be systematically tested in other parts of the world. Counter to the expectations generated by the Latin American experience, I find that leaders who pursue land reform in the Middle East and North Africa (MENA) have shorter tenures than non-reformers. This finding motivates my central research question: why are redistributive autocrats less likely to endure than their non-redistributive counterparts?
I address this puzzle in two stages. First, I argue that the legacies of European colonialism impacted the inclusivity of elite coalitions. In countries with legacies of exclusive coalitions, autocrats inherited more intense demands for redistribution than in countries with legacies of inclusive coalitions. Strong demands from previously excluded elites drove leaders to pursue radical land reforms. I use a medium-N quantitative analysis to uncover patterns regarding the implementation of land reform and the survival prospects of redistributive autocrats.
Second, radical reformers must also decide how to attract a loyal support coalition after redistribution is underway. Radical reformers who simultaneously extend cooptive state capacity through investment in and provision of “soft” institutions (e.g., agricultural cooperatives, health, education) are more likely to send a credible signal to potential members of an expanded supporting coalition. Alternatively, autocrats that pursue radical reform and rely on the expansion of repressive institutions (e.g., the military) are less likely to attract new supporters and are consequently more vulnerable to ouster. I turn to the case studies of Jordan, Iraq, and Egypt to disentangle the patterns suggested by the cross-national findings.
Hybrid quantum-classical algorithms and error mitigation
Keywords: Near term quantum computing

These days, research groups such as Google, Microsoft, and Rigetti are working towards fabricating quantum devices which have hundreds to thousands of qubits. In recently proposed quantum algorithms, i.e. hybrid quantum-classical algorithms, such quantum devices are used as subroutines for calculation of classically intractable tasks. However, the applicability of hybrid algorithms was quite limited, for example, the search of the ground state, and simulation of the dynamics of quan- tum systems. In addition, near-term quantum devices are expected to be quite noisy, impairing the precision of computation seriously and removing any potential advantages with quantum computers. Therefore, it is necessary to extend the applicability of hybrid algorithms and mitigate errors on quantum computers.
In this thesis, we describe the generalisation of hybrid algorithms so that they can be applied to variety of problems, such as search of the spectrum of quantum systems, simulation of open quantum systems and even general mathematical tasks. The algorithm for finding spectra is useful for applications such as new drug discovery, design of batteries. Generally speaking, quantum systems of interest to physicists, chemists, and materials scientists inevitably interact with their environments, and quantum states are decohered. Therefore, to investigate quantum phenomena, new algorithms simulating open quantum systems are described in this thesis. Algorithms for general mathematical tasks such as matrix multiplication to a vector and solving linear equations, useful for a large number of problems, such as machine learning, are also presented.
Furthermore, in order to make hybrid algorithms useful, we also invented a practical error mitigation method for suppressing physical errors, which may make hybrid algorithms useful. We showed that errors can be suppressed for a quantum system with over 50 qubits for the current achievable error rate, which is believed to be hard to simulate with classical computers. Also, we generalised the error mitigation technique to be applied to mitigate algorithmic errors, which may enhance the accuracy of Hamiltonian simulation.
Hunting for water with MCS
Keywords: Mars Climate Sounder
Infrared radiation
MCS
Mars

Mars Climate Sounder (MCS) is an infrared radiometer aboard NASA’s Mars Reconnaissance Orbiter (MRO) launched in August 2005 and designed to characterize the temporal and spatial variation of temperature, dust and water profiles. MCS has nine spectral channels in the range 0.3–50 μm. An original goal of the mission was retrieval of vertical water profiles. This was to be done using two spectrally co-located channels (centred at 42 μm)—a narrow channel (B3), which was mainly sensitive to dust, and a broader overlapping channel (B2) sensitive to both dust and water. This has been severely compromised by the fact that the B2 and B3 filters did not meet their specification, with a much wider than expected spectral response.
This thesis is split into three parts attempting to assess the current ability of MCS to retrieve water vapour. In the first part, work was done assessing the ramifications on the water vapour sensitivity of the B3-B2 pair and the B2 channel alone through extensive simulation work. The B3-B2 pair were found to have a drastically reduced sensitivity to water vapour that was further reduced by the presence of dust and low temperatures. Radiance residuals of B2 from MCS observations showed that a water vapour signal is present in the channel. Simulations of MCS radiances and retrieval of synthetic observations revealed that the accuracy of water vapour retrievals is sensitive to the choice of aerosol particle size and that in the presence of moderate aerosol opacity (dust and water ice), aerosol radiance contribution in B2 is falsely misinterpreted as water vapour.
In the second part, work was done measuring the spectral response of the B3 filter in order to understand the process behind the spectral broadening in the B-channels. It was thought that random forward scattering of out-of-bandpass radiation by the mesh filter may be the cause of the widening. Using a custom-made jig and FTIR spectrometer, measurements were taken at several filter-detector separation distances. No change in the B3 response FWHM was observed as the distance was varied. In the final part, a two-stage retrieval method was applied to MCS observations for MY28 northern hemisphere summer (Ls=111–173°). Nightside vertical profiles of water vapour were retrieved for the first time showing interaction with the aphelion cloud belt directly. Possible interaction between dust and water cycles was seen. Retrieval results compared favourably with observations by others for both column abundances and vertical profiles. Of particular note was good agreement with results from Clancy et al. (2017) using vertical water profiles derived from CRISM retrievals of 1.27 μm O2 (1∆g) dayglow. A number of spurious retrievals were seen and these are attributed to the aerosol model choice problem seen in the simulations.