VictorJuiz/thesis huggingface dataset:
Safe and certified reinforcement learning with logical constraints
Keywords: formal methods
Markov decision processes
reinforcement learning
policy synthesis
temporal logics

Reinforcement Learning (RL) is a widely employed machine learning architecture that has been applied to a variety of decision-making problems, from resource management to robot locomotion, from recommendation systems to systems biology, and from traffic control to superhuman performance in video games. However, RL has experienced limited success beyond rigidly controlled or constrained applications, and successful employment of RL in safety-critical scenarios is yet to be achieved. A principal reason for this limitation is the lack of a systematic formal approach to specify requirements as tasks (or learning constraints), and to provide guarantees with respect to these requirements and constraints, during and after learning. This work addresses these issues by proposing a general method that leverages the success of RL in learning high-performance controllers, while developing the required assumptions and theories for the satisfaction of formal requirements and guiding the learning process within safe configurations. Given the expressive power of Linear Temporal Logic (LTL) in formulating control specifications, we propose the first model-free RL scheme to synthesise policies for unknown black-box Markov Decision Processes (MDPs), where the reward function is formally shaped by an LTL specification. We convert the given property into a Limit Deterministic Buchi Automaton (LDBA), namely a finite-state machine expressing the property. Further, by exploiting the structure of the LDBA, we shape a synchronous reward function on-the-fly, and we discuss the assumptions under which RL is guaranteed to synthesise control policies whose traces satisfy the LTL specification with maximum probability possible. This probability (certificate) can also be calculated in parallel with policy learning when the state space of the MDP is finite: as such, the RL algorithm produces a policy that is certified with respect to the property. We also show that our method produces "best available" control policies when the logical property cannot be satisfied. The performance of the proposed method is evaluated via a set of numerical examples and benchmarks, where we observe an improvement of one order of magnitude in the number of iterations required for the policy synthesis, compared to existing approaches whenever available.
Immunological responses to retinal gene therapy
Keywords: immunity
adeno-associated virus
AAV
hydroxychloroquine
inflammation
retinal gene therapy

Dose-dependent inflammatory responses in adeno-associated virus (AAV)–mediated retinal gene therapy trials have restricted the use of high vector doses and impeded the ability to enhance therapeutic efficacy. Characterising the nature of this response, and devising methods to overcome it, are thus becoming increasingly important in the clinical application of gene therapies. In the experiments herein, I investigated the composition, timing, and magnitude of the cellular immune response to retinal gene therapy in mice using quantitative flow cytometric analysis. I observed a significant increase in retinal leukocytes from 14 days after subretinal injection of an AAV8 vector expressing green fluorescent protein (GFP). These consisted of a constant population of resident microglia and infiltrating peripheral leukocytes including macrophages, natural killer cells, CD4 and CD8 T cells, and natural killer T cells. An identical vector at an equivalent dose encoding a human therapeutic transgene elicited a diminished response compared to paired injections with a GFP vector. However, the proportions of the leukocyte populations remained similar, suggesting a common mechanism of immunity. In addition to the induction of a cell-mediated immune response, innate detection of AAV vectors may directly restrict transgene expression. Preliminary evidence suggested in vitro AAV transduction may be limited by the anti-viral nucleic acid sensors Toll-like receptor 9 and cyclic GMP AMP synthase, suggesting possible detection of transgenic AAV genomes. I also showed that the immunomodulatory drug hydroxychloroquine can significantly enhance AAV transduction in vitro, ex vivo, and in vivo, with indirect indication of the partial antagonism of TLR9. The lack of structural change in the retina following subretinal hydroxychloroquine delivery indicates that it could be a safe adjunct for improving retinal gene therapy efficacy.
A problem of industries and regions: unemployment and structural change in Britain during the interwar years and 1980s
Keywords: structural change
interwar
1980s
unemployment

The most serious employment crises in twentieth-century Britain occurred during the interwar years and the early 1980s, when, in both cases, the unemployment rate climbed to over 10% in aggregate and remained high for many years. Both downturns also coincided with periods of structural change in the economy: in the interwar years, export-oriented heavy industries lost out to expanding light manufacturing industries, and, during the early 1980s, the decline of manufacturing accelerated as the economy pivoted toward service industries and finance. A large literature on these recessions has dealt with aggregate demand fluctuations and supply factors, but this mainly macroeconomic focus has limited our understanding of the impacts of structural change. This thesis investigates the interaction of structural change and the business cycle in both the crises using newly-digitized industry microdata and econometric methods. How did structural change affect these employment downturns, and what were the consequences for workers and the labor market? I find that in both periods, secular structural change contributed significantly to, and was amplified by, the cyclical downturn. This interaction caused the im- pact of the interwar and early 1980s recessions to vary across industries, regions, gender, and demographic groups, with some workers experiencing persistent disadvantage.
Chapter I reviews how structural and cyclical unemployment were understood by economists in a pre-Keynesian setting. Chapter II analyzes interwar unemployment with novel data, finding that structurally-disadvantaged industries had higher unemployment and that the labor market was more flexible for some workers than others. On the early 1980s, Chapter III argues that structural change caused a jobless recovery from the 1980-1981 recession. Finally, Chapter IV uses individual-level data to demonstrate that this recession disproportionately affected workers from particular industries, regions, and demographic groups.
Stronger than they seem: 'parchment barriers' and the state of judicial independence in Hungary and Poland
Keywords: Democratic Backsliding
Poland
Hungary
Central Europe
Judicial independence
Judicial Politics
CEE
Constitutional politics

Judicial independence has been a particularly salient issue in the context of the rule of law in democracies and hybrid regimes in recent years. Actions to encroach on this independence are taken very seriously, evidenced by the Article 7 procedures against Hungary and Poland. A political consensus seems to exist that certain legal changes to their constitutional courts should be condemned as threats to judicial independence. In empirical works on the subject, however, a very different consensus exists, finding no strong relationship between ‘parchment barriers’, or de jure independence, and de-facto judicial independence. The gap between the political and scholarly consensuses is an important one, because resolving it should dictate policy responses to the very real problem of captured courts. This begs an interesting question– how have legal changes to the regulation and makeup of judiciaries affected actual judicial outcomes? This paper first inspects and reconsiders the key characteristics of de jure judicial independence, showcasing the need for more conceptual clarity between the relevant legal or constitutional provisions and the actual changes to the structures which judges, governments, and citizens operate within. It then analyzes constitutional court behavior in two country cases: Hungary and Poland. A two-part analysis is performed for each country case. First, the effects of all legal changes which occurred on overall court outcomes are estimated. Second, the specific mechanism of how changes to the judicial appointment process can influence individual judge behavior is investigated. The results of these analyses provide tentative evidence that the legal changes to the constitutional courts of both countries are related to a decrease in the likelihood of a case being decided against the preferences of the ruling government. In both cases, this appears to be at least partly driven by the behavior of judges appointed through more politicized appointment processes, which rule in favor of the government more often. Ultimately, the paper provides support for the notion that formal rules can and do affect behavior. It also highlights the inherent relationship between calls to increase the democratic representation and legitimacy within minority institutions, and the greater possibilities of their majoritarian capture.
Time-series analysis of B[e] supergiant stars
Keywords: astrophysics
B[e] supergiant
binary star
GG Carinae
stellar physics

B[e] supergiant stars (B[e]SGs) are a rare and unusual class of massive evolved stars which are poorly understood. I demonstrate how studying \sgBeshorthand s by analysing time-series observations reveals key information about this stellar class which may help to build a common picture and determine the origin of their phenomena. I utilise spectroscopic data from the Global Jet Watch, which is able to observe astronomical objects with sustained high time-resolution, and describe my contributions to the data reduction pipeline. I access and analyse high-resolution FEROS spectra, and photometry from the ASAS, ASAS-SN, OMC, and TESS surveys.
I take an in-depth case study of the B[e]SG binary GG Carinae, which has been widely studied but poorly understood. I demonstrate that previous determinations of the binary's orbital solution were incorrect and accurately measure it for the first time, finding that the binary is significantly eccentric (e=0.50+/-0.03) and that the system is brightest at periastron. I discovered a pulsation mode in the system from photometric and spectroscopic variability, and analysed it in depth for the first time. The variability has a period of 1.583156+/-0.0002 days and displays amplitude modulation over the binary's orbital period, such that the amplitude of the detected variability is largest just after periastron. The variability is most likely due to an l=2 f-mode pulsation in the primary which is modulated by the time-varying tidal potential in the eccentric orbit. I study the two atomic circumbinary rings of GG Carinae and find evidence of subtle variability of the line centres and the blue-peak to red-peak ratios of the emission lines arising from the inner circumbinary ring over the FEROS observations. I show these variations may be caused due to the binary exciting the circumbinary rings to higher eccentricities over the observation timescales.
A preliminary study utilising TESS and ASAS-SN data of the Galactic B[e]SG sample reveals signatures of binarity in a further three specimens. This increases the ratio of confirmed or suspected binaries in the Galactic B[e]SG population from 4/9 to 7/9, indicating that binarity may be key in understanding the phenomenon. Pulsations similar to those seen in GG Carinae are also detected in at least two further objects for the first time, demonstrating that pulsations may also be a commonality of the class.
Multiplicative relations among special points of modular and Shimura curves
Keywords: André--Oort conjecture
unlikely intersections
modular functions
O-minimality
Zilber--Pink conjecture

We consider a number of Diophantine problems for (mixed) Shimura varieties. Specifically, we look at the multiplicative relations satisfied by special points of modular and Shimura curves. These problems are closely related to the André--Oort and Zilber--Pink conjectures, and we will resolve some special cases of these conjectures.
Let Y
be a modular or Shimura curve. Let V⊂Y×Gm
be an algebraic correspondence defined over
¯
Q
. For each n≥1
, we prove that all multiplicative dependencies among n
V
-images of special points of Y
belong to one of finitely many components of Vn
of a particular special kind.
We then strengthen this result in the case that Y
is the modular curve Y(1)=SL2(Z)∖H
and V
is the graph of a (suitably generic) rational function. In this case, we prove that, for each n≥1
, there are only finitely many n
-tuples of distinct V
-images of special points which are multiplicatively dependent and minimal for this property. The key ingredient in this strengthening is a functional multiplicative independence statement for modular functions, which we prove.
Finally, we give a complete classification of the triples of singular moduli which have rational product. We show that all such triples are trivial'' in a suitable sense. This establishes a completely explicit André--Oort statement for the family of cubic surfaces defined (in C3
) by an equation x1x2x3=α∈Q
.
Viral haemorrhagic fevers in pregnancy with a focus on lassa fever
Keywords: pregnancy
clinical trial participation
vaccine trials
lassa fever
seroconversion
transplacental transfer
seroprevalence
viral haemorrhagic fever

The viral haemorrhagic fevers (VHFs) are thought to be major causes of morbidity and mortality in pregnant women. However, there remains a paucity of evidence in pregnancy, due in part to the exclusion of pregnant women from clinical trials. The recent occurrence of large VHF outbreaks, coupled with the increased vulnerability of Sub-Saharan Africa to VHF epidemics, particularly in areas reporting high poverty and high maternal mortality increases the importance of improving our understanding of VHFs in pregnancy.
The thesis sets out to generate evidence to inform disease control and clinical trial design and implementation by investigating the epidemiology of the VHFs in pregnancy and exploring issues around trial implementation. It consists of three results chapters. Chapter 2 is an epidemiological evidence synthesis of the priority VHFs in pregnancy. It identifies research gaps and facilitates selection of one of the VHFs for in-depth study. Chapter 3 sets the stage for the next two results chapters. Chapter 4 investigates three gaps in the epidemiology of Lassa fever in pregnancy. Specifically, prevalence, incidence, and risk factors for Lassa fever, and begins work on the kinetics of Lassa antibodies in pregnancy by presenting evidence regarding transplacental transfer of Lassa antibodies. Chapter 5 explores issues around trial implementation by generating qualitative evidence specific to participation, recruitment, and retention of pregnant women in Lassa fever clinical trials.
The thesis presents new data on the epidemiology of the VHFs in pregnancy, particularly Lassa fever, which facilitates estimation of disease burden and, as such inform policy for disease control and drug and vaccine development. It describes trial design and implementation issues that arise with respect to the inclusion of pregnant women in clinical trials and suggests relevant actors and subject areas for effective trial implementation.
Understanding Valanginian continental climate using δ18O from sphaerosiderites as a proxy for precipitation
Keywords: Valanginian
Wealden
sphaerosiderite
cretaceous

Terrestrial and marine carbon isotopes record a significant perturbation of the global carbon cycle during the Valanginian: the Valanginian positive Carbon Isotope Event (CIE). The CIE was associated with warm, invariant, low-latitude sea surface temperatures, increased humidity, and ocean fertilization. Although marine changes are well documented, terrestrial temperatures and hydrological response during the CIE are not yet fully understood. The non-marine Wealden Supergroup of Southern England (Berriasian–Hauterivian) provides an ideal record for reconstructing low-latitude continental palaeoclimate during the CIE. These strata contain abundant sphaerosiderites, spherical iron carbonate concretions (FeCO3), which formed mainly in wetland environments and are thought to record meteoric δ18Ogroundwater reflective of regional hydrology. Wealden δ18Osiderite varies between –3.5‰ and 0.6‰ VPDB, Δ47 temperatures are 33–39° C, and reconstructed groundwater values are isotopically heavy (–3.7‰ to 2.6‰ VSMOW). Compositional and morphological heterogeneity of the sphaerosiderites, comparison to experimental siderite syntheses, isotope transects of individual spheres, high Δ47 temperatures, and comparisons to climate models suggest that the sphaerosiderites are a seasonally, summer-biased palaeohydrological record.
The δ18Osiderite values from sphaerosiderite horizons alternate between isotopically heavy and light values, interpreted as drier (less precipitation/higher evaporation) and wetter (higher precipitation/less evaporation) conditions, respectively. Correlation to marine records using carbon isotope stratigraphy suggests synchronous relatively arid periods at the onset of the CIE, and just proceeding the peak of the CIE. A peak in humidity observed in the Tethyan realm during the peak of the CIE cannot be assessed conclusively in the Weald basin, due to poor siderite and organic matter preservation in the Wadhurst Clay. A facies-specific δ13Corg shift and these poorly-preserved sphaerosiderites suggest a significant palaeoenvironmental change during deposition of the Wadhurst Clay, which needs further assessment. The geochemical records from the Weald Basin indicate that low-latitude terrestrial temperatures continued to be warm during the Valanginian CIE, supporting evidence from sea surface temperature reconstructions, and that there was periodic enhancement of the hydrological cycle during the Valanginian.
Pudeur, place, and print: modesty, agency, and collaboration in sixteenth-century French women’s writing
Keywords: women's writing
early modern France
print
Marguerite de Navarre
literary collaboration
women and agency
pudeur
collaborative modesty
Dames des Roches
Gabrielle de Coignard
modesty

This thesis considers responses to modesty in the works of four sixteenth-century French women writers who work with and reclaim modesty in different ways. I focus on Marguerite de Navarre, the Dames des Roches, and Gabrielle de Coignard who span the sixteenth century and operate in different locations: Nérac, Poitiers, and Toulouse. Firstly, I examine how far their works reflect discourses of modesty in circulation, and whether these responses are shaped by the locations, physical and thematic, in which they live. Occasionally tracking (im)pudeur and cognate terms, this exploration mainly offers textual commentaries on these key terms: virginity, chastity, desire, sex, the female body, nudity, shame, and silence. I document how the importance of modesty changes over time and the shifts or movement between locations in the production and circulation of texts, from salon-type structures to printed works. The process becomes more complex when considering common associations between print and sexual deviance which compromised a woman’s modesty. A second aspect of this thesis explores a creative response to this nexus, which I term ‘collaborative modesty’: networks of male and female collaborators that influence the composition, publication, and reception of women writers’ texts. Alongside the intervention of male figures, a striking mother-daughter relationship emerges; daughters play a vital role in how their mothers are received in print, contemporarily and retrospectively. This thesis reconsiders understandings of early modern French women writers as ‘submissive’ or ‘subversive’, by focusing on the agency that they achieve within the confines of society. Secondly, it offers a new concept of collaboration which dispels the myth of ‘male genius’ that for too long defined understandings of authorship. Literary collaboration is translocational and transactional; it does not simply consist of poets and writers. ‘Modest’ figures such as daughters, printers, and editors, all play an important role in literary creation.
The doctrine of the mean in Aristotle’s ethics
Keywords: Doctrine of the mean
Hartmann
McDowell
Silencing account
Aristotle

In this thesis I build on the scholarship on Aristotle’s doctrine of the mean that has proposed an interpretation closely connected to ideas of harmony and especially Aristotle’s notion of the καλόν. The central question of this paper is whether Aristotle’s application of the idea of harmony to ethics presents, as for example Hursthouse has argued, a fruitless spillover of a vacuous principle or rather a substantial ethical position. As a first step, I will argue that Aristotle envisages the doctrine of the mean to be at its core concerned with the intensity of a person’s affective response. Having established this central connection of the doctrine with the emotions, I will situate the emotions in the wider terrain of Aristotle’s ethics in particular with respect to moral formation and motivation. Having followed the argument for a reading of the mean as tied to ideas of harmony, as epitomised in Aristotle’s notion of the καλόν, I contrast two fundamentally different readings of the harmony Aristotle envisages. McDowell seems to suggest that such a harmony stems from a silencing of contrary reasons due to the distinct perception of the virtuous person, while Hartmann, who seems largely overlooked in the anglophone debate, understands the mean as the expression of a fundamental tension at the heart of ethics. In light of the textual material in the Nicomachean Ethics, I argue against McDowell’s silencing account as an interpretation of Aristotle and building on Hartmann argue that the doctrine of the mean may be read as a position of substantial insight in terms of ethics and moral psychology. In particular, I argue, the doctrine of the mean may be read as capturing the remarkable dual demands the virtuous person has to integrate on the level of personality. The contrast between McDowell and Hartmann, furthermore, elucidates what I read as Aristotle’s attempt to accommodate for two distinct senses of human excellence – one as essentially responsive, the other informed by and reflecting a correct understanding of values.