VictorJuiz/thesis huggingface dataset:
Topological effects on the quantum properties of magnetic nanographene molecules
Keywords: EPR
magnetism
materials science
physics
chemistry
carbon

Graphenoids are nanometer-sized flakes that share the same honeycomb framework of graphene. Novel chemistry has allowed the bottom-up synthesis of molecular graphenoids with atomic-like control of their structure. The electronic properties of these finite-sized graphene nanoislands actively depend on the topology of their edges and their pi-electron network. Rational design of the topology in terms of size, conjugation, and presence of defects, has highlighted exotic magnetic properties that were predicted for quantum confined graphene structures. The presence of free spins, and the similarity to the graphene lattice would render them promising materials for all carbon-based spintronic and quantum devices. While a large number of structures are being synthetised by chemists everywhere, the quantum properties of these molecules remain widely unexplored.
In this work, we study the quantum properties of three categories of graphenoids: units with pentagonal defects, segments with zigzag edges, and ring-shaped molecules. Defects have been observed in graphene and are expected to play a key role in its optical, electronic, and magnetic properties. However, because most of the studies focused on the structural characterization, the implications of topological defects on the physicochemical properties of graphene remain poorly understood. Zigzag segments of carbon edges are a fundamental ingredient for most proposals of graphene nanostructures: they allow nontrivial topologies, where spin states can be used for quantum information processing and new communication pathways. Ring structures are intriguing for their aromatic and antiaromatic properties, and because they could show compelling quantum interference patterns.
In this thesis, we use EPR to study the quantum properties of ensemble of isolated molecules. We measure coherence times at different temperatures and in different hosting matrices in order to evaluate structural and environmental effects on the properties. The molecular graphenoids obtain large coherence times up to room temperature that we compare to metal-based molecular systems and inorganic systems. We use advanced decoupling sequences to increment the coherence of the systems. Finally, we suggest synthetic strategies to remove the main channels of decoherence. These results shine new light on the fundamental quantum properties of topological defects and edge states in nanographene structures.
Breaking the deadly triad in reinforcement learning
Keywords: off-policy learning
reinforcement learning
the deadly triad

Reinforcement Learning (RL) is a promising framework for solving sequential decision making problems emerging from agent-environment interactions via trial and error. Off-policy learning is one of the most important techniques in RL, which enables an RL agent to learn from agent-environment interactions generated by a policy (i.e, a decision making rule that an agent relies on to interact with the environment) that is different from the policy of interest. Arguably, this flexibility is key to applying RL to real-world problems. Off-policy learning, however, often leads to instability of RL algorithms, if combined with function approximation (i.e., using a parameterized function to represent quantities of interest) and bootstrapping (i.e., recursively constructing a learning target for an estimator by using the estimator itself), two arguably indispensable ingredients for large-scale RL applications. This instability, resulting from the combination of off-policy learning, function approximation, and bootstrapping, is the notorious deadly triad in RL.
In this thesis, we propose several novel RL algorithms theoretically addressing the deadly triad. The proposed algorithms cover a wide range of RL settings (e.g., both prediction and control, both value-based and policy-based methods, both discounted and average-reward performance metrics). By contrast, existing methods address this issue in only a few RL settings, where our methods also exhibit several advantages over existing ones, e.g., reduced variance, improved asymptotic performance guarantee. These improvements are made possible by the use of several advanced tools (e.g., target networks, differential value functions, density ratios, and truncated followon traces). Importantly, the proposed algorithms remain fully incremental and computationally efficient, making them readily available for large-scale RL applications.
Besides the theoretical contributions in breaking the deadly triad, we also make empirical contributions by introducing a bi-directional target network that scales up residual algorithms, a family of RL algorithms that break the deadly triad in some restricted settings.
Contributions to the numerics of quadratic backward SDEs and probability on turbulence
Keywords: Turbulence
BSDE
Numerical method

In this thesis, we first study the numerical scheme of path-dependent quadratic backward stochastic differential equations (quadratic BSDE or QBSDE for short). Under the assumption that the terminal condition is of the form Φ(X), where Φ is a Lipschitz function on D(Rm) (the space of càdlàg paths) and X is the solution to a Lipschitz SDE satisfying linear growth conditions, we derive the path-regularity result which characterises the solution (Y,Z). Motivated by the modified implicit BTZ scheme, we propose the modified (inner) explicit BTZ scheme and conduct a perturbation analysis on Z-part of the scheme, followed by concluding the error of the scheme is O(N−1/2)) with N as the number of timesteps instead of O(N−1/2+ε)) for some ε > 0 in the modified implicit BTZ scheme. Numerical experiments support our conclusion on the convergence rate.
The second purpose of this thesis is to derive a partial differential equation (PDE) for the single-time single-point probability density function (PDF) of the velocity field of a turbulent flow. The PDF PDE is a highly nonlinear parabolic-transport equation, which depends on two conditional statistical characteristics of important physical meaning. The PDF PDE is a general form of the classical Reynolds mean flow equation, and is a precise formulation of the PDF transport equation. The PDF PDE provides us with a new method for modelling turbulence. An explicit example is constructed, though the example is seemingly artificial, it demonstrates the PDF method based on the new PDF PDE.
Lastly, vorticity random fields of turbulent flows are singled out as the main dynamical variables for the description of turbulence, and the evolution equation of the PDF of the vorticity field has been obtained. This PDF evolution equation is a mixed type PDE of the second order which depends only on the conditional mean (which is a first order statistic) of the underlying turbulent flow. This is in contrast with Reynolds’ mean flow equation which relies on a quadratic statistic. The PDF equation is interesting on its own and is worthy of study as a PDE of second order.
Legislative and adjudicative ideals: the role of political morality in statutory interpretation
Keywords: legal interpretation
statutory interpretation
philosophy
law
jurisprudence
legal philosophy

In Law’s Empire, Ronald Dworkin articulates four ideals of political morality: integrity, justice, fairness, and procedural due process. Although he explicitly articulates integrity in both a legislative and adjudicative principle, the other ideals remain somewhat vaguely defined. However, Dworkin’s analysis of constructive interpretation gives rise to the view, often present but unstated in theories of statutory interpretation, that the ideals which guide legislation should also guide interpretation. If legal reasoning is a matter of interpreting in view of the object of interpretation’s purpose, in order to devise a theory of statutory interpretation, we must first look to the purposes and ideals of the object in question: legislation.
While I reject Dworkinian integrity as a viable ideal, the remaining three values offer important guidance. Fairness and due process both require strict textual fidelity, both from legislators in crafting laws and from judges in interpreting those laws. Justice requires that laws pursue legitimate purposes using legitimate means. Legislators must draft laws in this way and judges must interpret laws as though they have been drafted in this way. To draw out the complexities of this view, we can look to the classical legal concept of equity, particularly as expressed in the philosophy of Thomas Hobbes. Equity, for Hobbes, is a legal interpretive principle which demands that laws be interpreted in view of both the law’s immediate purpose, as well as the ultimate purpose of all laws – the reason that the government was instituted – which Hobbes argues is safety.
Finally, we can apply our insights regarding statutory interpretation to other spheres of legal interpretation. Adrian Vermeule’s common good constitutionalism provides a methodologically similar, explicitly Dworkinian example of a theory of constitutional interpretation, through which we can explore legal interpretation in general.
Half-souled bodies: punishing civil servants for past state atrocities
Keywords: transitional justice
complicit responsibility
civil servant
punishment
retributivism

This thesis investigates the principal question of whether civil servants should be punished for past state atrocities under transitional circumstances. It looks into three sub-questions to answer this principal question. First, it inquires into whether retributivism provides an application justification of punishment in transitional circumstances. By addressing challenges about the effectiveness of punishment, the standing of the punisher, and the retroactivity of punishment, it argues that expressivist retributivism offers a defeasible justification for punishing civil servants in transitional circumstances. Second, it examines how civil servants can be held complicitly responsible for state atrocities. It proposes that an individual is complicitly responsible for a collective wrongdoing if she has taken an action that carries an impermissible risk of causing the collective wrongdoing’s success, and this action expresses a culpable choice. It also argues that this principle of complicit responsibility can overcome the problem of overdetermination. Third, it investigates what valid justifications and excuses civil servants can claim to counter blame and punishment. It rejects the cog-theory justification, the superior order justification, and the excuse of absent discriminatory intent. However, it argues that non-culpable ignorance can excuse civil servants' contribution to atrocities, and their ignorance is non-culpable if they have fulfilled their respective level of epistemic obligations. Therefore, this thesis argues that any civil servants who have contributed to state atrocities and cannot appeal to any valid justification or excuse deserve to be punished. If there are no forward-looking considerations that can outweigh retributive justice in the transitional context, these civil servants should be punished.
The democratic road to socialism (again): strategies of Anglo-American democratic socialism 2015-2020
Keywords: Jeremy Corbyn
socialist strategy
non-reformist reforms
Bernie Sanders
democratic socialism
class-struggle elections
capitalist democracy
Democratic Socialists of America
British Labour Party
in and against the state
capitalist state
rational choice

This thesis attempts to assess the strategic questions and possibilities raised by the coming to prominence of ‘democratic socialism’ in the UK and US in 2015- 2020, with the rise of Jeremy Corbyn and the Labour left on the one hand, and of the Democratic Socialists of America, spurred on by the campaigns of Bernie Sanders, on the other. In doing so, it also hopes to give readers an account of what, in fact, ‘democratic socialism’ constitutes in the contemporary Anglo-American context, and, crucially, make out what might productively differentiate it from other socialist orientations on the question of strategy. In particular, the thesis argues that contemporary democratic socialism presents a coherent answer to a key strategic challenge: how, given the dual improbability of either a revolutionary or moderate, gradualist method of socialist transformation, to proceed as a socialist actor seeking transformational change in the context of a capitalist democracy. However, whether democratic socialism presents a convincing answer to this challenge, the thesis argues, is open to debate.
In order to achieve its aims, the thesis combines the academic literature on socialist strategy and rational political choice in capitalist democracies, with the political literature produced by the contemporary Anglo-American democratic socialist movement itself, while also inspecting the real practices of that movement. The thesis focuses on three strategic elements of the democratic socialist movement: non-reformist reforms, in and against the state, and class-struggle elections.
Measuring composition and strain in bimetallic catalyst nanoparticles using advanced electron microscopy
Keywords: strain
STEM
fuel cell
composition
nanoparticle
catalyst
electron microscopy

Polymer electrolyte membrane fuel cells (PEMFCs) are promising energy-conversion devices due to their high efficiency and near-zero carbon emission footprint. PEMFCs still require a high mass of precious metal Pt as an electrocatalyst for oxygen reduction reaction (ORR) to ensure sufficient power output efficiency, but the sources and cost of Pt greatly limit its commercial application in fuel cells technology. The development of high-active and low-cost ORR electrocatalysts is therefore of much significance for the commercialization of fuel cells. Compared to Pt, bimetallic (Pt-Co) nanoparticles exhibit superior catalytic performance with less mass of precious metal, but the intrinsic mechanism of this catalytic enhancement has not been fully explained. Strain and composition are two fundamental effects that are highly associated with the catalytic activity of the Pt-based nanoparticles. Thus, being able to measure local composition and strain at an atomic scale within the individual nanoparticle will further our understanding of the operation of heterogeneous catalysts.
In this thesis, the strain analysis and composition quantification are precisely and simultaneously performed on the individual nanoparticle at an atomic scale for four Pt-Co nanoparticle ensembles, to relate composition and size to strain. We find that no compressive strain on the Pt-rich outer shell is imposed by the alloy core. Dilation strain is found to be distributed throughout the individual nanoparticles, with the radial dilation strain being much larger than the circumferential dilation strain at the surface. Remarkably, all the Pt-Co stoichiometries studied have a relatively invariant surface lattice parameter, which is smaller than that for pure Pt but larger than that predicted using the measured local composition, whether or not an acid de-alloying treatment is applied. This work makes it possible to design the optimum ORR catalysts by tuning strain, composition, and structure of the Pt-based bimetallic nanoparticles.
"The stuffe not ours": the work of derivation in early modern Englishwomen's writing
Keywords: atomism
early modern women
Mary Sidney
Epicureanism
romance
originality
Anne Lock
sonnet
derivation
psalm
women's writing
paraphrase
Protestant
early modern literature
feminism
Lucy Hutchinson
Lucretius
Espejo de príncipes y cavalleros
formalism
De rerum natura
Anne Dowriche
Margaret Tyler
The Mirror of Knighthood
authorship
translation
chivalric romance

Twentieth-century critics sought writing by women that captured authentic female voices of the past, but primarily found derivative texts: translations and paraphrases. These texts were deemed emblematic of a patriarchal dynamic, with women silenced by the male-authored source text. The disappointment palpable in this scholarship, where women’s texts are seen as insufficiently subversive, has long affected the critical fortunes of early modern women’s writing in English. This thesis argues instead that the authentic female voice is a misnomer for the real interest of derivative texts, namely evidence of women’s authorship: the will and capacity to make. Far from mechanical exercises, women’s translations and paraphrases abound in all that we associate with canonical genius: creativity, intellectual vigour, political comment, and formal experimentation. My chapters address writers as various as Anne Lock, Mary Sidney, Margaret Tyler, Anne Dowriche, and Lucy Hutchinson. Moving between a range of literary genres in which they wrote, as well as a range of derivative modes, I demonstrate the diverse interests of these writings, including many areas of thought and action typically assumed to exclude women. Far from constituting a distinctly female tradition, their derivative texts demonstrate the continuity of women’s engagements with the intellectual mainstream. As such, they reveal that the mainstream was never entirely male to begin with.
Policing illegal drug and wildlife trades - the role of the police, legal online platforms, private organisations and individuals, and cybercriminal traders
Keywords: policing
cybercriminal trade

This thesis explores the actors and activities involved in the policing of online illegal drug and wildlife trades on the Darknet and surface web. As the role of policing evolves due to advances in technology, the blurring of national boundaries, the increasing knowledge and skills of other actors, and the growing volume and value of these trades, more research is required about who and what is involved in this endeavour to increase its efficiency.
Policing has been argued to take place in a network, where various actors come together to perform operations (Dupont, 2004). One of the most recent policing classifications is Button (2019)’s policing taxonomy which involves technological components. This thesis designs its own policing framework and tests the relevance of Button (2019)’s model in the context of online illegal drug and wildlife trades. Beyond the Police which possess powers of search and arrest to protect citizens, legal online platforms have created trading policies and are monitoring and punishing misconduct on their sites to preserve their legality and reputation. Organisations and individuals in the private sector, non-profits, and academia have been gathering, analysing, and sharing data and expertise to help Police investigations and inform the public. Cybercriminal traders have also taken advantage of others for their own financial gain and consequently decreased trust on Darknet markets, as well as unintentionally providing the Police with ways to disrupt their markets from the inside.
This exploratory research used mixed social science methods to gather complimentary quantitative and qualitative insights. Semi-structured interviews were performed with 20 experts in Police agencies, legal platforms, for-profit and non-profit organisations, and academia. The content of 200 Police and private organisation reports, news articles, blog posts, and legal platforms’ trading policies was analysed. A pilot laboratory experiment also tested the behaviour of 138 participants following trust-related policing interventions in a fictitious online marketplace.
This thesis contributes to the fields of sociology and (cyber)criminology by designing a new cyber policing classification based on the policing of online illegal drug and wildlife trades and by formulating the first ‘policing script’ summarising the activities various policing actors perform in this context, when, with whom, and how they complement each other.
Patterns and processes of recovering large mammal communities
Keywords: roe deer
trentino
predator-prey interactions
wolf
ungulates
carnivores
bio-energetic models
step selection analysis
nature recovery
trophic interactions
integral projection models
trophic cascades
Yellowstone National Park
animal movement
migration

Despite the global biodiversity crisis, some ecosystems are showing encouraging signs of recovery, especially in Europe and North America. We do not have a clear understanding of how ecosystems recover from degraded states, of the causes and consequences of such recovery, or of how emerging species interactions affect and are affected by ecological processes. In this thesis, I investigate the patterns and processes emerging from recovering ecosystems by analysing population dynamics, species interactions and animal movement.
I explore the spatiotemporal trends of an expanding large mammal community in the Alps and investigate predator-prey interactions between wolves and their main prey. I assess the permeability of the Alpine landscape for recovering populations, by analysing the impact of natural and anthropogenic factors on the movement of a partially migratory ungulate. Studying species interactions in a dynamic and recovering system such as the Alps is challenging. I therefore focus on the Yellowstone ecosystem to analyse the impact of wolf predation on their prey and on other ecological processes. I develop a mechanistic, bio-energetic model of the vegetation-elk-wolf system, to study how energy acquired through resources flows across trophic levels influencing population dynamics and interactions. I then use this model to study how ecological and evolutionary change can affect complex tri-trophic systems.
I show that large mammal communities can recover relatively quickly in the right environment, and with the support of conservation and favourable environmental legislation. Nonetheless, humans can still have a significant impact on animal populations by affecting their movement patterns and habitat use. In the Alps, I could not detect an impact of wolf predation on prey populations because the recovery process is still ongoing and the system is highly dynamic. In Yellowstone, on the other hand, I show that wolf predation can have significant effects on the ecosystem, and that complex trophic interactions can respond in unexpected ways to ecological and evolutionary change.
My thesis offers advances for investigating complex terrestrial systems, for predicting the potential impacts of environmental change on ecosystems, and for informing future policy and landscape management decisions.