VictorJuiz/thesis huggingface dataset:
Novel device architectures for perovskite solar cells

The aim of the work presented in this thesis is to study the opto-electronic properties of semi-conducting perovskite materials when being used in unconventional solar cell device configurations. Being a young technology, perovskites as solar cell materials have seen an unparalleled rise in the research community which has driven the fastest performance inflation to power conversion efficiencies competing with the ones of long established single crystalline technologies. The ability to process perovskites inexpensively makes them the new hope in the fight against climate change. Herein device architectures were developed with a special focus on potential commercial applications.
Initially the work in this thesis has been motivated by the interest in crystal growth and morphology of perovskite thin-films, which has led to the study of confined crystal growth within microstructures. Controlling the crystal domain geometry enabled the fabrication of enhanced semi-transparent devices. More efforts were directed into the improvement of specifically neutral colour semi-transparent devices, which could be improved via a simple treatment of selectively attaching shunt-blocking layers. Furthermore, a back-contacted perovskite device design was introduced, which allows not only for the fabrication of a new type of perovskite solar cell, but also represent a great material testing platform to study perovskite and electrode characteristics. This led to the discovery of charge transport distances, that exceed those of other thin-film devices.
Finally, perovskite-on-silicon tandem solar cell designs were analysed through a rigorous optical model to estimate the expected real world energy yield from such systems. Important implications include the fact that two terminal tandem solar cells come close to four-terminal configurations and can overall compete, in relative terms, well with established single junction silicon cells.

Keywords: Device architecture
Perovskite
Energy yield
Advisor: Snaith, H
Cell type-specific Runx1 enhancer-reporter mouse lines to study hemogenic endothelium

Hematopoietic stem cells emerge from a specialized subset of endothelial cells in the midgestation mouse aorta. This subset, the so-called hemogenic endothelium (HE), undergoes a morphological and molecular change to a hematopoietic cell type, as part of the endothelial-to- hematopoietic transition (EHT). Previously, lack of specific markers prevented mechanistic studies of HE, as well as studies into its developmental origin. Runx1 is a critical regulator of developmental hematopoiesis and is expressed in all cell intermediates of EHT. Identification of the Runx1 +23 enhancer led to the development of enhancer-reporter tools in order to isolate HE for further analysis. Here, I investigated the cell-type specific activity of another Runx1 enhancer, located 204 kb downstream of the ATG in exon 1. I generated a novel enhancer-reporter mouse line (204GFP) and determined the expression pattern and lineage potential of 204GFP+ cells. It was established that the +204 enhancer marks all HE and part of the HSCs. Hematopoietic progenitor cells, in contrast, were not marked by the 204GFP transgene. Interestingly, the 204GFP reporter also marks part of the Runx1- expressing sub-aortic mesenchyme. To test whether the 204GFP reporter could enrich for HE when combined with a Runx1 +23 enhancer-reporter transgene, I generated and characterized a 23Cherry transgenic mouse line. Expression analysis of aortic endothelial cells marked by both the 204GFP and 23Cherry transgenes using the Fluidigm platform indicated an enrichment of cells with a HE expression signature. This enrichment will facilitate further analysis of the molecular networks active in HE using whole genome expression profiling. The Runx1 enhancer-reporter models are also valuable tools to track the developmental origin of HE, which remains to be established in the mouse embryo. To this end, I mapped the precise spatio-temporal expression pattern of the 23GFP transgene in pre- somitic embryos and established lineage tracing experiments. This provides the basis to revisit fate mapping of the primitive streak to determine the origin(s) of the HE lineage.

Advisor: De Bruijn, MT
The social functions of intergroup schadenfreude

Schadenfreude is a German word, which describes the pleasure that people take in someone else’s misfortune. The aim of the present research was to investigate the social functions of intergroup schadenfreude. Chapter 2 presents Studies 1 – 3, focusing on the social functions of experiencing intergroup schadenfreude in the context of football tournaments, using both concurrent and retrospective methods. Study 1 did not find any relation between change in perceived relative status and intergroup schadenfreude, possibly because of the sample’s low domain interest and identification. However, schadenfreude was positively associated with change in status in Study 2 and with change in performance evaluation in Study 3 as expected. Also, across all three studies, intergroup schadenfreude was associated with consequences corresponding to its social distancing (e.g., distance from or dislike of the outgroup and intention to humiliate its members) and social affiliation functions (e.g., intention to celebrate with ingroup members). Importantly, schadenfreude mediated the effects of change in status (Study 2) and performance evaluation (Study 3) on these consequences. Chapter 3 presents Studies 4 and 5, which investigated whether social status is specifically associated with intergroup schadenfreude, and examined whether this social concern helps to differentiate intergroup schadenfreude from victorious joy (i.e., happiness about a third-party’s victory). I developed a new experimental paradigm to manipulate participants’ concern for status to elicit feelings of intergroup schadenfreude. I also manipulated participants’ concern for external rewards associated with the third-party’s victory to prompt victorious joy. However, in both studies, the concern for external rewards was the main influence on both intergroup schadenfreude and victorious joy, although a multivariate interaction between the two motives affected these emotions in Study 4. Hence, these studies suggest that status may be only one of the many motives underlying intergroup schadenfreude. Chapter 4 presents Study 6, which was a vignette-based study investigating the social affiliation functions of sharing intergroup schadenfreude as a function of ingroup identification. Participants read tweets from an ingroup member expressing either intergroup schadenfreude or victorious joy. Identification was also manipulated. However, results showed that recipients of intergroup schadenfreude messages formed more negative impressions of the tweeter and intended to distance themselves from him/her more than recipients of victorious joy messages. Chapter 5 provides an overview of the findings, contributions, and limitations of these six studies and discusses directions for future research. Overall, this thesis went beyond the current focus on the antecedents of schadenfreude and took steps towards the development of a social-functional account of intergroup schadenfreude.

Keywords: Intergroup Relations
Schadenfreude
Social Psychology
Emotion
Advisor: Parkinson, B
The spatial organization of the epidermal growth factor receptor on the surface of colorectal carcinoma cells

The discovery of the existence of the cell membrane has led to a search for its organization on a molecular scale. The advent of artificial lipid bilayers and the development of electron microscopy in the 1930’s provided direct visual evidence for the existence of the cell membrane and drove forward models of membrane structure based its known composition of proteins, lipids and carbohydrates. The fluid mosaic model of membrane structure, based on thermo- dynamics and newly developed protein structural studies of the time, placed integral globular membrane proteins within a fluid phospholipid bilayer. This model allowed for the association of proteins into groups and the possible mobility of proteins within the lipid bilayer. At the the same time fluorescence microscopy demonstrated movement of proteins in the plane of the lipid bilayer. Since then experimental techniques have been developed that show protein complexes of varying sizes do exist and so this gives us the opportunity to ask how receptor proteins fit into the molecular organization of the cell membrane.
This thesis presents an investigation into how the epidermal growth factor receptor (EGFR) organizes in the cell membrane of colorectal carcinoma cells. First a new cell line for studying the receptor by stably expressing the epidermal growth factor receptor conjugated to enhanced green fluorescent protein (EGFR-eGFP) in SW620 cells was developed. This is an interest- ing cell line because it originates from a colonic adenocarcinoma that during the process of metastasis has lost the ability to express the EGFR. It therefore provided an environment for the expression of the fluorescent form of the receptor more in keeping with its natural environment.
The technique of total internal reflection fluorescence (TIRF) microscopy was used to visualize the fluorescently tagged receptor in the cell membrane. This technique uses the principles of total internal reflection to excite fluorescence in molecules located only 100 nm into the cell. Because sources of fluorescence from outside the illuminated area are minimized individual fluorescent molecules can be imaged. The spots in the images, produced by the fluorophores, were detected using a single molecule detection and tracking algorithm. The intensities of these detected spots were analysed and compared with that from a single molecule of enhanced green fluorescent protein (eGFP). This gave an estimate of the number of receptors contained within each receptor complex.
Before ligand binding most of the receptors were found to be located in complexes containing up to eight molecules and most frequently they were found in complexes of two molecules. Larger complexes of receptors were found to have formed after activation of the receptor by its ligand.

Keywords: total internal reflection fluorescence microscopy
Advisor: Leake, M
Bodmer, W
Enhanced array design for tidal power generation

Tidal stream energy is a predictable source of renewable energy. Tidal stream turbines have been proposed as a way to extract useful energy from the tide. Many arrays of such devices will need to be installed to extract significant amounts of energy. The presence of an array of turbines within a tidal flow will impact the flowfield, as complex fluid interactions occur across multiple scales. This thesis is concerned with the behaviour of tidal turbines arrayed across channels. Experimental and analytical work is carried out to investigate array behaviour and to create new modelling tools to replicate this behaviour.
Linear Momentum Actuator Disc Theory (LMADT) is employed to develop a new analytical model for a long row array of tidal turbines split into multiple smaller, co- linear row arrays. An argument of separation of scales is used to facilitate this model. It is found that increases in power extraction beyond that of a single continuous row array are possible.
Experimental work is carried out on a row array of eight porous discs, simulating a short row array of tidal turbines. Disc porosity and spacing are varied to investigate thrust on the array, flow behaviour behind the array and an 'inferred' power removed from the flow. The results are compared to previously developed theoretical models. Good agreement is found with the trends of the analytical model, for example that there is a peak power coefficient which can be reached through appropriate selection of spacing and disc resistance. Differences from theory are found in the total thrust and power measurements, as well as in some aspects of the flow behaviour in the array wake. Reductions in thrust and power towards the ends of the array are also identified as 'end effects' which are not included in the analytical model.
Based on these results a new semi-empirical model is proposed, using LMADT with experimental data closure. This model allows variation of the disc resistance across a row array. Values from the experimental work are used as inputs to the model, and the results compared to experimental measurements of flowspeed, thrust and power. Although agreement with experimental results is found in some areas, there are still some discrepancies between the analytical model and the experimental results. This indicates that there are additional factors that contribute to end effects on a short row array.

Keywords: Porous discs
Analytic modelling
Tidal turbine arrays
Experimental modelling
Advisor: Willden, R
Byrne, B
Finiteness Properties and CAT(0) groups

In this thesis, we explore several areas of geometric topology. We first prove that all groups G which fit into a short exact sequence F2&hookrightarrow; G &twoheadrightarrow; ℤ, act properly, freely, cellularly and cocompactly on CAT(0) square complexes. This shows, among other things, that their cubical dimension is equal to their geometric dimension.
In the second part, we consider finiteness properties of subgroups of CAT(0) groups. We construct two infinite families of finitely presented subgroups of hyperbolic groups, that are not themselves hyperbolic. We also construct the first examples of CAT(0) groups that do not contain ℤ3 subgroups but have subgroups of type FP2 that are not finitely presented.
We give examples of groups that are of type Fn-1 not of type Fn and contain no free abelian subgroups of rank > ⌈n⁄3⌉.
In the final part of the thesis we examine stable diffeomorphisms of smooth 4-manifolds and place an upper bound on the number of S2× S2
summands required to gain a stable diffeomorphism.

Advisor: Bridson, M
Future searches for rare astrophysical signals and detector commissioning in SNO+

SNO+ is a 780 kTonne liquid scintillator experiment, situated 2km underground in the Creighton mine near Sudbury, Ontario and primarily designed to study neutrinoless double beta decay, but also has several other physics goals such as solar neutrinos, reactor and geo-neutrinos and supernova neutrinos. SNO+ may also be sensitive to rare astrophysics signals, such as Axion-Like Particles (ALPs) originating from the Sun. This thesis predicts a limit on the ALP-electron coupling, |gAe × g3AN| &LT; 1.1 × 10−11 via the axio-electric effect and a limit on the ALP-photon coupling of |gAγ × g3AN| &LT; 3.0 × 10−11 GeV−1 via the inverse Primakoff interaction, which could be achieved with 5 years of Te-loaded scintillator phase of SNO+. Both of these upper limits are an order of magnitude improvement on the current published limits on ALP couplings.
SNO+ should also be sensitive to another rare astrophysics signal: a burst of neutrinos from a supernova, originating from our Galaxy, via proton elastic scattering (PES) and inverse beta decay (IBD) interactions within the scintillator. The ratio of PES/IBD interactions, due to supernova neutrinos, is determined by the vx/ve flux ratio. This ratio could indicate a preference for the inverted neutrino mass hierarchy, due to a proposed dramatic 'spectral swapping' between vx and ve flux distributions caused by neutrino-neutrino interactions from the corecollapse of a supernova. The initial commissioning of the data acquisition (DAQ) and scattering calibration (SMELLIE) systems, during SNO+ data commissioning runs taken in December 2014, is also evaluated in this thesis.

Advisor: Biller, S
Testing the neurocognitive model of  antidepressant treatment

The neurocognitive model of antidepressant treatment action states that antidepressants work by producing relatively immediate positive shifts in emotional processing, which translate into clinical improvement with time. Short-term or even acute doses of antidepressants can, for example, increase memory for positive self-referent words or decrease amygdala activation to fearful faces, and these early changes correlate with later clinical improvement. However, there are a number of ways in which the model needs further probing. The aim of this thesis was to test the neurocognitive model by: 1) investigating whether changes in emotional processing occur in an antidepressant with a novel mechanism of action, St John’s wort, as the model predicts; and 2) examining whether there is a comparable pattern of neuropsychological changes to citalopram in a population of high neurotic volunteers, whose baseline emotional biases may make them a more ideal group in which to study drug effects. We found that seven days of St John’s wort produced similar changes to other antidepressants, for example reducing recognition of disgusted faces and attention to fearful faces while increasing memory for positive words. The drug did not affect other aspects of cognition including working memory and reward learning. These findings support the theory that early psychological changes are a common feature of all antidepressants. On the other hand, four weeks of citalopram treatment produced apparently contradictory effects in high neurotics, increasing memory for positive words but also increasing recognition of negative facial expressions. Neuroimaging data showed that high neurotics had greater response to neutral faces in emotional processing areas compared to low neurotics, which was reduced with citalopram. High neurotics also showed increased resting state connectivity in default mode network areas and between amygdala and cortical areas, which was again reduced with citalopram. We suggest that in this group citalopram corrects general negative emotional processing biases, but also works to decrease a natural aversion to particularly threatening socially-relevant stimuli. Overall this thesis supports the idea that early changes in emotional processing are vital for antidepressant action, but also suggests that in certain groups such as high neurotics, some changes may be more nuanced than previously reported and warrant further scrutiny.

Keywords: emotion
neuroimaging
mood disorders
antidepressants
neuroticism
Advisor: Harmer, C
An EU-centric account of the rule of law

The rule of law is declared to be a foundational and guiding value of the European Union in Article 2 Treaty on European Union. The European Commission claims to be the ‘guardian of the rule of law’, and the concept has been determinative in judgments in the Court of Justice of the EU. However, the EU has not defined what exactly is meant by ‘the rule of law’. This leads to the question: how can the EU claim to be guided by the rule of law, ‘common to all Member States’, but not provide an account of what that means in practice? To determine such an account, I examine contemporary accounts of the rule of law and identify the specific nature of the EU. I conclude that while the rule of law is a shared value across legal systems, distinct accounts develop within, and adapt to, each one. I advance an EU-centric account of the rule of law (EUCA) which is apt for the EU legal order. I advocate the value of EUCA first in abstract by providing reasons for why it is to the benefit of the EU Institutions, the Member States and individuals to endorse EUCA compliance. I then show the practical use of EUCA as a source of legitimacy from the perspective of Member States and individuals in the context of issues of contemporary and pressing concern in the areas of international trade, corporate taxation and the criminal law. I seek to bridge the gap between a theoretical account of the rule of law apt for the EU legal order, and the practical guidance it can provide in the resolution of crisis issues. I conclude on the essential importance of guarding, strengthening, and enhancing the rule of law throughout the EU, not just as a means of resolution in times of crisis, but as a guarantee of the future of the European Union.

Keywords: rule of law
European Union law
Advisor: Craig, P
Securing reform? Post-election power sharing and security sector reform in Zimbabwe, Kenya, and Togo, 2006-2013

Power-sharing arrangements have become the default tool of international actors to resolve a vast range of conflicts worldwide, with a particular concentration in sub-Saharan Africa. Traditionally used to end high-intensity civil wars, recently power sharing has increasingly been used to terminate an array of lower-intensity conflicts, such as election-related violence in Togo in 2006 and Kenya and Zimbabwe in 2008. The thin but emerging scholarship on post-election power sharing is largely negative, maintaining that the model is unlikely to deliver the institutional reforms necessary to resolve the underlying roots of electoral conflicts. Yet the cases of Kenya, and, to a lesser extent, Togo, appear to complicate this narrative, suggesting that post-election power sharing may be able to deliver some key but thorny institutional reforms, such as security sector reform. While the power-sharing model continues to be used worldwide and security reform is widely identified by scholars and practitioners as critical to durable peace, the existing literature has generally ignored the potential link between the two.
As such, this dissertation seeks to answer the following questions: Does post-election power sharing lead to security sector reform? Which causal factors are most important in shaping security reform outcomes under post-election power sharing, and through what processes or mechanisms?
The two-step integrated theoretical framework presented here forwards a structured contingency approach, positing that a combination of long- and short-term domestic and international factors will drive or stymie reform of the security sector under post-election power sharing in democratizing countries. In short, the theory argues that two main longterm factors, the nature of civil-military relations and the character of external involvement, combined with two short-term mechanisms, the design of the political agreement and the type of political strategy deployed by the parties, will be the most important factors shaping security reform outcomes under post-election power sharing. I demonstrate that post-election power sharing plays a significant role in the causal process of security reform and can deliver some institutional reforms, under certain conditions.
The dissertation uses the method of structured, focused comparison to build and apply the theoretical propositions to the cases of Kenya, Togo, and Zimbabwe. Using process tracing and the logic of most-similar comparisons, I conduct two sets of cross- and within-case comparisons, utilizing elite interviews as the primary tool for data collection. I conducted over 100 interviews with key decision-makers in my case countries—including former prime ministers, cabinet ministers, top political party leaders, senior security officials, and international stakeholders.

Advisor: de Oliveira, R