VictorJuiz/thesis huggingface dataset:
Magnetotransport in Graphene: A study of Quantum Hall Breakdown, Energy Loss Rates, and Weak Localization
Keywords: Nanotechnology
Magnetotransport
Carbon

This thesis reports magnetotransport measurements in graphene Hall bar devices. Graphene samples fabricated from different techniques (epitaxial growth on silicon carbide, exfoliation, and CVD) are measured and compared. Measurements are taken primarily using a 21T magnet, at liquid Helium 4 temperatures.
The first three chapters present the background for the work. Chapter One details the motivation for the thesis, and gives a general background to carbon and the state of carbon research. Chapter Two covers the theoretical background of graphene, including the anomalous quantum Hall effect and weak localization. Chapter Three covers the synthesis of graphene and a typical procedure undertaken for device fabrication.
The next three chapters report experimental results. Chapter Four presents measurements of the energy loss rates in exfoliated graphene. The mechanism of carrier energy loss is investigated, and compared to theory. Further, the breakdown of the quantum Hall effect in the device is investigated, demonstrating peak current densities far in excess of those found in the literature for exfoliated graphene. Chapter Five shows measurements comparing the carrier energy loss rates in graphene derived from the epitaxial, exfoliated and CVD fabrication techniques. An unconventional method for measuring the energy loss rate based on measuring the weak localization peak is developed, and trends in the energy loss rates with carrier density are investigated for a wide range of devices. Chapter Six reports a comparison of the decomposed weak localization scattering lengths from graphene devices derived from the epitaxial and CVD methods, and compares these to measurements from the literature. Further, a previously reported saturation of the weak localization in graphene is investigated, and demonstrated to be an experimental artefact.
This thesis provides a development of the understanding, and an experimental verification, of several aspects of heat transfer in graphene. An understanding of heat transfer is of critical importance to proposed high-density nano-electronics, and bolometry applications. The high breakdown currents and observed trends in carrier density are also of significant assistance in the design of low-cost resistance metrology devices based on graphene.
Coordination of frontline workers for improving the health of children in Rajasthan (India) : a case study
Keywords: Integration
Community Health Workers
India
Coordination
Frontline Workers
Convergence
ASHA
Cooperation
NRHM

All governments aim to ensure better health and nutrition to children. The Rajasthan state (India) has implemented a unique frontline coordination model where Accredited Health Social Activist (ASHA) Sahyoginis are expected to support two other frontline workers (FLWs) i.e. the Anganwadi Workers from the Integrated Child Development Services and the Auxiliary Nurse Midwives from the Health department to improve child health. This thesis focuses on examining the existing coordination between the three groups of FLWs in Rajasthan by exploring FLWs' participation in child immunisation and Vitamin A supplementation (two common activities), service coverage and beneficiary's' knowledge (expected outcomes), and the challenges faced and areas that need improvement for better frontline coordination.
A mixed methods design was used. Sixteen villages from two blocks (tribal and non-tribal) of Udaipur district (Rajasthan) were selected using multistage purposive sampling. The formative stage included 12 FLWs' in-depth interviews (IDIs) as well as a review of FLWs' job descriptions to understand the process and government expectations on their participation in routine childhood immunisation, polio camps, routine Vitamin A supplementation and Vitamin A campaigns. The next stage included data collection from the 16 selected villages i.e. structured questionnaire survey of FLWs (46), observations of Maternal and Child Health and Nutrition Day (16), review of FLWs' immunisation and Vitamin A registers (32) and a structured questionnaire survey of registered infants' mothers (321)-all to ascertain the actual participation of FLWs in these four activities and the outcomes. IDIs with FLWs (46) and FLWs' line managers (17) were conducted to understand their experience, issues and solutions for better frontline coordination.
The participation of FLWs in three of the four activities (except Polio Camps) was found to be limited. The FLWs and their line managers were also dissatisfied with coordination between FLWs. Poor outcomes also indicated unsatisfactory coordination. Overall, frontline participation and outcomes were better in tribal than non-tribal villages. A variety of factors (i.e. personal, professional, organisational, and geo-socio-cultural) appeared to affect coordination between FLWs.
Appropriate recruitment, training, monitoring and supervision and rewards to the FLWs along with greater political commitment for coordinated approached and addressing intra-departmental challenges are proposed to improve frontline coordination and child health in Rajasthan.
How does the chromatin remodeler ATRX identify its targets in the genome?
Keywords: non-B DNA structures
ATR-X syndrome
G-quadruplexes
chromatin remodelling factors
G4
GC-rich tandem repeats
R-loops
ATRX

ATRX is a chromatin remodeling protein associated with X-linked Alpha-Thalassemia Mental Retardation syndrome and cancers that use the Alternative Lengthening of Telomere pathway. In the absence of ATRX there is a DNA damage response associated with telomeres and the expression of certain genes are perturbed. Recent findings (Law et al, 2010 Cell) have shown that ATRX is preferentially enriched at GC-rich tandem repeats in the genome. The mechanism for this localisation is unknown but may be related to the potential for these GC-rich tandem repeats to adopt non-B form DNA structures; ATRX has been shown to bind such structures (G4) in vitro. This study aims to understand the specific factors of the repeats that signal ATRX targeting.
To address the research questions, an experimental system was developed, in which known targets, the ψζ VNTR and telomere repeats, were inserted into an inducible ectopic gene in the 293T-Rex cell line by site-directed recombination.
ATRX was found to be enriched at the ectopic repeats compared to an endogenous negative control suggesting that it is recruited by the repeats independent of its original context. Furthermore, ATRX enrichment increased upon transcription of the ectopic gene, and this was dependent on the orientation of the repeat with the non-template strand being G-rich. Interestingly, when the repeat was transcribed, the distribution of ATRX across the repeats was asymmetrical with most ATRX binding downstream of the repeat. Moreover, there was a direct correlation between the repeat size and level of ATRX bound: the longer the repeat the higher the increase in ATRX enrichment.
To determine the signal for ATRX binding, assays were performed to look for features which reflected the distribution of ATRX including H3K9me3, RNA polII, G4, R loops and DNA supercoiling. R loops look to be a strong candidate for the signaling of ATRX binding.
The role of inflammasomes in intestinal inflammation
Keywords: mucosal immunity
Inflammasome
intestinal inflammation

Single Nucleotide Polymorphisms (SNPs) in the intracellular pattern recognition receptor gene NLRP3 are associated with susceptibility to Crohn’s disease, a form of inflammatory bowel disease (IBD). Following cell damage or infection, NLRP3 triggers the formation of inflammasomes, a multimolecular protein complex containing NLRP3, ASC and caspase-1, which mediate secretion of IL-1β and IL-18. NLRP3 inflammasome activation in macrophages has been implicated in protection against several pathogens, but whether NLRP3 activation in tissue cells contributes to protective immunity against bacterial pathogens is unknown. We show that upon infection with the attaching/effacing (A/E) intestinal pathogen Citrobacter rodentium, Nlrp3-/- and Asc-/- mice displayed higher bacterial colonization, more weight loss and exacerbated intestinal inflammation. We further show that Nlrp3 inflammasome activation in intestinal epithelial cells (IECs) acts rapidly after infection to limit bacterial replication and penetration, and inhibits the development of inflammatory pathology in the gut. We also show that epithelial Nlrp3-mediated protection is independent of the classical inflammasome cytokines IL-1β and IL-18. Thus an Nlrp3-Asc circuit in IECs regulates early defense against a mucosal pathogen and limits inflammation in the intestine. Nlrp3 inflammasome activation has also been implicated in protection in acute models of experimental colitis, but its role in chronic models of colitis is unknown. We found that Asc signaling is necessary for the development of innate chronic intestinal inflammation driven by Helicobacter hepaticus. Thus while deficient inflammasome signaling in tissue cells increases susceptibility towards enteric pathogens, excessive inflammasome activation can drive chronic intestinal inflammation.
Silk cocoons as composites
Keywords: cocoon
biocomposites
biomaterials
silk

This thesis looks at the engineering aspects of silkworm cocoons as a structural biological composite system. A wide range of species of silk cocoons were studied for their morphologies, physical properties and mechanical behaviour. A silk cocoon can be described very broadly as a nonwoven fibre composite made of silk fibres bonded by sericin binder, although the a variety of species can show a diversity of structural features of the layers, porosity, degree of orientation, binding density and presence of crystals etc. These structural differences lead to diverse cocoon mechanical behaviour. Tensile and compressive properties of cocoons are tested and linked to their individual interfibre bonding, connectivity and density. Gas diffusion through the cocoon walls is controlled by the combination of thickness and density.
In addition, a physically realistic quantitative model is developed, which links directly the structure and mechanical properties of silk cocoons. The gradual loss of connectivity of the interfibre bonding is the key mechanism for the deformation of cocoons. It can be quantified as a strain activated function of the bonding up to a failure criterion, where either a percolation threshold of 50% of these bonds or the failure stress of the binder arrives. For Bombyx mori cocoon, which has a graded-layer structure, the model was enhanced to include the contribution of interlayer and intralayer bonding in the system. This model can also be applied to other nonwoven fibre and particulate composites using a small number of physically realistic model parameters, and will be a valuable ‘bioinspired’ tool for the development of new composite systems.
Based on the understanding of structure-mechanical property relationships in silkworm cocoons, an engineering approach was used for examining cocoon as an impact resistant structural material that provides mechanical protection from environmental threats. In addition, silk cocoons were used as a nonwoven reinforcement to develop an engineering composite by increasing the connectivity (more binder) in the cocoon. Using polyurethane or regenerated silk fibroin of medium concentration can increase the toughness of cocoons, and epoxy or regenerated silk fibroin of high concentration binding leads to a brittle system.
Inventing the veteran, imagining the state: post-conflict reintegration and state consolidation in Timor-Leste, 1999-2002
Keywords: Timor-Leste
veterans
Post-conflict transitions
pensions
reintegration

Conventional post-conflict state-building models approach disarmament, demobilisation, and reintegration (DDR) programmes as a means for state actors to delegitimise non-state sources of power and centralise control over coercive power with the state. The programmes carry the promise of new lives for conflict actors and a new, modern and technocratic approach to the exercise of force; they are thus central to post-conflict transformation. However, this thesis calls into question the naturalisation of 'state' and 'conflict' actors in DDR models. Instead, it finds that DDR programmes create these categories and, in doing so, serve to mask and facilitate continuities in elite power.
This thesis examines the case of Timor-Leste. In Timor-Leste, the country's new leaders - resistance actors cum state actors - have centralised legitimate power, while, at the same time, incorporated non-state, resistance-era networks and identities upon which their authority depends. The key technology through which this order has been established is a suite of reintegration programmes. In registering over a quarter of a million people and dispersing significant funds, this programme has emerged as a tool of governance. Again challenging the idea of a 'state' acting upon 'veterans', this thesis finds that these programmes constitute these identities. The act of defining non-state conflict actors who may no longer legitimately wield force also necessarily defines the category of state actors who may wield force.
In asking what these programmes 'do,' this thesis rejects conventional readings of reintegration practices as security-driven or processes like registration as purely administrative challenges. As such, this study introduces a critical, new perspective on the political economy of post-conflict reintegration programmes. It supports its findings through a mixed methods approach, combining a robust, representative survey of over 220 former resistance members with ethnographic observation and 90 semi-structured elite interviews. This thesis is thus of relevance to those interested in DDR, conflict networks, and state-building.
The Human Rights Act, asylum, and the campaign against Section 55
Keywords: civil society
social justice
human rights
asylum
law

A major objective of the Human Rights Act (HRA) was to bring about a culture of rights in the UK. Its introduction fore-grounded questions about the use of rights to advance social justice issues and was the impetus for this research. At about the same as the Act came into effect another law, Section 55, an antithesis of what the HRA promised, was passed which forced thousands of asylum-seekers into destitution. Section 55 became a major battleground pitting non-governmental organisations (NGOs) against the Home Office in a three-year long campaign, characterised by rancour and viciousness, unlike any in recent memory. The NGOs, with the new HRA as a key part of their strategy, defeated the legislation. This thesis, a bottom-up case study of rights at work, examines the role of rights in the campaign to assess (1) if rights brought about social changes and (2) is a culture of rights developing in the UK? The paper first considers the various theoretical frameworks on rights and social change and analyses various case studies of rights at work. Context is important; therefore, it also examines how asylum has come to be framed in present-day discourse, with an overview on the evolution of welfare as a coercive measure. The study, framed against current events of the day, concludes that while test-case challenges eventually defeated Section 55 welfare as a coercive measure continues. In short, the HRA has proven to be ineffective against illiberal policies and the development of a culture of rights, insofar as asylum is concerned, has stalled. And it has happened with deliberation by a government determined to be tough on asylum irrespective of the HRA.
Charge transport in disordered semiconductors in solid state sensitized solar cells: influence on performance and stability
Keywords: charge transport
perovskite solar cells
dye sensitized solar cells

This thesis studies parameters influencing both the performance and stability of solid state sensitized solar cells (ssSSCs). ssSSCs benefit from their low materials and manufacturing processing costs, a consequence of using solution processed materials. However, solution processed materials are often structurally and electronically disordered. By characterizing fully operational ssSSCs and their charge transport properties, this thesis elucidates the factors limiting charge transport and proposes routes towards both improved photovoltaic conversion efficiency and long-term stability.
Chapter 2 provides an explanation of the operation of ssSSCs, while Chapter 3 discusses the basic methods used in this thesis. Having set this background, Chapter 4 explores the interaction between atmospheric oxygen and charge doping mechanisms in the organic semiconductors used in ssSSCs. To understand the implications of the findings presented in Chapter 4, a new technique, “transient mobility spectroscopy”, was developed to understand the evolution of balanced charge transport behaviour of disordered semiconductors at different operating conditions in ssSSCs. This technique is presented in full in Chapter 5.
The understanding gained in Chapters 4 and 5 suggest that alternative light absorbers with higher extinction coefficients may be beneficial to improving the performance of ssSSCs. Chapter 6 discusses the use of an organometal trihalide perovskite, as light absorber in ssSSCs. Using time resolved techniques, the charge transport and recombination mechanisms in various device architectures are explored, allowing suggestions to be made towards future improvements.
Chapter 7 uses the technique presented in Chapter 5 to understand a rapid degradation mechanism of working ssSSCs. Particular focus is placed on the titanium dioxide charge-transporting layer. Building on this newfound understanding, two methods for attaining stable photovoltaic performance are provided, a great step forward for this technology.
The political economy of natural gas producer cooperation: cartelisation and market power
Keywords: natural gas
natural gas prices
producer conduct
cooperative behaviour
economic cooperation
collective action
LNG
artificial market entry barriers
economic rent
cartel
GECF

In 2001 the Gas Exporting Countries Forum (GECF) was created by some of the world’s leading natural gas producing and exporting countries in order to promote their mutual interests through cooperation, in particular with regard to extracting the maximum value from their natural gas exports.
My core research question is: Does cooperation among GECF member countries explain those exporters’ market power in highly import-dependent natural gas consuming countries? To determine the influence of the GECF’s cooperative actions and policies, I study the GECF’s cooperative behaviour and measure the role of (collusive) producer conduct in terms of its contribution to achieving the main GECF objective: attaining gas prices that are measurably above the cost of production and hence help producers earn significant economic rents. I employ a variety of methods from the international relations literature on cooperation and cartelisation, collective action theory and an economic measurement model in three case studies.
I find that cooperation among GECF members partly explains their market power in a number of import-dependent gas markets. This is so despite the GECF’s weak degree of institutionalisation. The reasons for the GECF’s influence on effective cooperative results are: first, conducive structural conditions in many gas importing markets favouring cartelisation; second, GECF members use methods such as artificial market entry barriers (e.g. long-term term contracts negotiated in a non-transparent way) to secure their market power and third, the GECF faces less severe internal procedural challenges that plague other cartels such as collective action problems, especially cheating.
Cooperation among GECF exporters hence contributes to high(er) prices of natural gas. This causes economic inefficiencies and a transfer of wealth—and political power—from gas consumers to producers. It also hinders climate change mitigation as cleanerburning gas remains too expensive to replace ‘dirty’ coal in power generation.
Translocal identities: an ethnographic account of the political economy of childhood transitions in northern Thailand
Keywords: transitions
migration
anthropology
Thailand
childhood

This thesis examines Karen childhood transitions in a context of expansion of the cash economy, formal education and modern institutions. Since the 1960s, Thai state development has had a significant impact on the organisation of work and learning among highland populations. Today, household economies largely depend on cash income and children aspire towards an adult life in which paid work is central. Formal education is highly valued as a means to reach this goal. Children often migrate for education to better-resourced locations and access scholarships provided by national and international institutions. On the basis of 12 months of ethnographic fieldwork undertaken between October 2007 and September 2009, the thesis seeks to understand the effects of globalisation on politically and economically marginalized children in northern Thailand through the lens of changing modes of production and learning. Findings indicate that children’s migration for education reflects broad political economic inequalities among Karen households as well as between them and mainstream Thai lowland populations. International dimensions of unequal relations are revealed in local peoples’ collective negotiations with Japanese and Catholic Christian NGOs. Although socio-cultural constructs like ‘gender’, ‘generation’, and ‘ethnicity�� shape Karen childhoods, this study found that their economic and political status are more fundamental in shaping all aspects of their social lives, including their socio-cultural identities. Childhood transitions emerge as multidimensional learning processes towards mastery of ‘translocal identities’, the skill to manage identities and relationships across multiple spaces and institutions. This is a culturally valued skill evidenced when minority children tactfully negotiate differing modes of compliance, resistance, and adaptation, especially in the domains of work and education. Thus, children participate in the moulding of local versions of the modern political economy of northern Thailand.