VictorJuiz/thesis huggingface dataset:
Tent-maps, two-point sets, and the self-Tietze property
Keywords: tent-map
two-point set
retractifiable
self-Tietze

This thesis discusses three distinct topics.
A topological space X is said to be self-Tietze if for every closed C ⊂ X, every continuous f : C &rightarrow; X admits a continuous extension F : X &rightarrow; X. We show that every disconnected, self-Tietze space is ultranormal. The Tychonoff Plank is an example of a compact self-Tietze space which is not completely normal, and we establish that a completely normal, zerodimensional, homogeneous space need not be self-Tietze.
A subset of the plane is a two-point set if it meets every straight line in exactly two points. We show that a two-point set cannot contain a dense Gδ subset of an arc. We also show that the complement of a two-point set is necessarily path-connected. Finally, we construct a zero-dimensional subset of the plane of which the complement is simply-connected.
For ⋋ ∈ ℝ, the tent-map with slope ⋋ is the function f : [0, 1] &rightarrow; ℝ such that f(x) = ⋋x for x &leq; ½ and f(x) = ⋋(1 - x) for x &geq; ½. Properties of w-limit sets of tent-maps, i.e. sets of the form
⋂
n∈ℕ
_________________
{ fn + k (x) | k ∈ ℕ }
for x ∈ [0, 1], are examined, and an example of a tent-map and a closed, invariant, nonempty, internally chain transitive subset of [0, 1] which is not an w-limit set is given.
Multicomponent fractional quantum Hall effects
Keywords: Fractional quantum Hall effect

This thesis scrutinizes the condensed matter physics phenomenon known as the fractional quantum Hall effect (FQHE), in particular fractional quantum Hall effects occurring in multicomponent systems. Broadly speaking, the FQHE can be defined as a many-electron quantum phenomenon, driven by strong interactions, that occurs in two-dimensional electron gasses in the presence of a perpendicular external magnetic field (and it is also predicted to occur for any two-dimensional particles, such as confined cold atoms, in an external gauge field). Multicomponent systems are systems where the constituent particles (such as electrons or cold atoms) possess internal degrees of freedom, for instance a spin or valley index. These internal degrees of freedom are often overlooked when modeling the FQHE.
Taking into account the multicomponent degree of freedom yields an abundance of possibilities for the intellection of new types of so-called “topological phases of matter”, which are ubiquitously associated with the FQHE. In this thesis several different cases are considered. The first topic discussed herein is a study of phase transitions that can take place between FQHE phases with different net values of their multicomponent degrees of freedom. Examples are phase transitions between phases of different uniform net spin polarization, tunable as a function of certain system parameters. Some significant technical refinements are made to a previous model and comparisons are made with a variety of different experiments. The results are relevant for multicomponent FQHEs occurring in GaAs,AlAs and SiGe semiconductor systems where the electronic structure is confined to two dimensions, as well as in two-dimensional materials such as graphene.
The second topic discussed herein is the introduction of the multiparticle multicomponent pseudopotential formalism. This methodology is oriented towards considerably expanding an existing framework for the construction of exactly solvable FQHE models by parameterizing multicomponent interactions. The final topic is the first example application of this new formalism to the construction of an exactly solvable FQHE model.
Qadizadeli Revivalism reconsidered in light of Ahmad al-Rumi al-Aqhisari's Majalis al-abrar
Keywords: Turkey
Ahmad al-Rumi al-Aqhisari
Ottoman Islam
history
Qadizadelis

Shaykh Aḥmad al-R­ūmī al-Āqḥiṣārī (d. 1041/1632), Ḥanafi jurist, theologian and Sufi, is largely an unknown figure to scholars of Ottoman religious history. Progress towards disclosing key aspects of al-Āqḥiṣārī’s thought has been made in recent times thanks to the important contributions of Y. Michot, who has, in particular, demonstrated the association of al-Āqḥiṣārī with the Ottoman puritanical movement, the Qaḍīzādelis. Building upon Michot’s work, this study delves further into the works of al-Āqḥiṣārī especially his seminal contribution, the Majālis al-abrār. The study sets out its main themes and the authorities on which it is based; it then moves to show the degree of overlap between al-Āqḥiṣārī’s understandings and Naqshbandī Sufism, as well as the extent to which his thought converges with that of better-known Ottoman puritans such as Birgivī Efendī (d. 981/1573) and Qaḍīzāde (d. 1044/1635). It is suggested that the impact of the Majālis al-abrār on the Qāḍīzādelis had the outcome in the second half of the seventeenth century of increasing the violence of their activists, a development which ultimately led to their downfall.
A key aspect of this study is the re-examination of the view that the Qāḍīzādelis were a proto-Wahhābī or proto-Salafī movement, which is typical in the existing literature. Whilst demonstrating the influence of Ibn Qayyim al-Jawziyya (d. 751/1350) and his teacher, Aḥmad b. Taymiyya (d. 728/1328), upon al-Āqḥiṣārī’s thought, the limits of this influence are clearly demonstrated by bringing to light al-Āqḥiṣārī’s distinct doctrinal and legal positions, which were very much embedded within the Ottoman Islam of his times. Ultimately, by studying the relationship between al-Āqḥiṣārī’s masterpiece, the Majālis al-abrār and Qāḍīzādeli and Naqshbandī beliefs, the study aims to place the movement in its own Ottoman, Ḥanafī, and Sufi milieu, thereby challenging the dominant approach which reads the movement through modern paradigms.
Development of models and methods to assess the efficacy of anti-cancer drugs targeted to the mitochondria
Keywords: oxidative phosphorylation
glucose
cancer metabolism
Warburg effect

Background: Malignant transformation of cells is typically characterised by aerobic glycolysis, resulting in supressed mitochondrial function, a state that helps resistance to apoptosis. This characteristic has been widely accepted as a hallmark of cancer and has been shown to be of critical importance in tumour development. The bioenergetic differences between normal and malignant cells are being exploited to identify potential cancer specific therapeutics. Improved in-vitro models are required to aid the identification and assessment of candidate drugs. In this project, we investigated the bioenergetic phenotypes of a panel of adult and paediatric cancer cell lines and evaluated the potential of 3D models as a platform for testing drugs that target cancer metabolism. We also investigated a novel method to assess mitochondrial function that enables the quantification of the level of oxygenation within the cell.
Results: The results presented in this thesis show that not all cancers display this aerobic glycolytic phenotype. We found that while some cell lines displayed the Warburg phenotype others displayed high levels of oxidative metabolism. These bioenergetic profiles need to be considered when deciding which anti-cancer drugs to use in a chemotherapeutic regime. If a bioenergetic pattern can be identified it may one day form the basis of a screening strategy for tumours. Dichloroacetate (DCA) is a small molecule PDK inhibitor that was investigated in this study. It was found to be relatively non-toxic to cells cultured in 2D but had improved toxicity when the cells were cultured in a 3D environment. Lastly, we evaluated a new oxygen sensing nanoprobe, Mito-Xpress Intra, and the results demonstrate its potential as a non-invasive means of measuring oxygen concentrations within the cell in real time as well as highlighting some striking differences between applied ambient and measured intracellular oxygen concentrations.
Conclusion: The findings suggest that not all cancers display the characteristic glycolytic phenotype. They also highlight the importance of controlling oxygen and glucose levels when evaluating metabolism and when drug testing.
An integrative approach to understanding the fitness cost of rifampicin resistance in Pseudomonas aeruginosa
Keywords: experimental evolution
rifampicin resistance
pleiotropy
systems biology
fitness cost of antibiotic resistance mutations
transcriptome profiling
compensatory mutations

Antibiotic resistance in bacteria is acquired through spontaneous chromosomal mutations or horizontal gene transfer. In the absence of antibiotics, resistant mutants generally show reduced fitness due to compromised growth rate, competitive ability and virulence compared to their antibiotic-sensitive ancestors. The focus of my research is to dissect the molecular underpinnings of the variations in the fitness cost of chromosomal antibiotic resistance using a systems-level approach. From an evolutionary perspective, my research aims are to understand how the fitness cost influences adaptation in resistant populations in an antibiotic-free environment. Using rifampicin resistance in Pseudomonas aeruginosa as a model, my work shows that most of the variation in the fitness cost of rifampicin resistance can be attributed to the direct effect of rifampicin resistance mutations on transcriptional efficiency. Through RNA-Seq transcriptome profiling, I demonstrate that global changes in gene expression levels associated with resistance mutations are surprisingly subtle, suggesting that the transcriptional regulatory network of P. aeruginosa is robust against compromised transcriptional efficiency. Using experimental evolution and whole-genome sequencing, my work reveals a systematic difference in the genetic basis of adaptation in mutants that were propagated in the absence of antibiotics. During compensatory adaptation, resistant mutants can recover the fitness cost of resistance by fixing second-site mutations that directly offset the deleterious effects of resistance mutations. Amongst resistant mutant populations with low fitness costs, general adaptation limits compensatory adaptation, which is most likely to be due to the rarity of compensatory mutations and clonal interference. Far from being the most ubiquitous mechanism in the evolution of resistance, compensatory adaptation is the exception that is more likely to be observed in resistant mutants with high fitness costs. In addition, I applied key elements of the integrative experimental approach developed in this work to dissect the molecular basis of the fitness cost associated with carriage of the pNUK73 small plasmid in P. aeruginosa, which carries the rep gene encoding a plasmid replication protein. My results confirmed that rep expression generates a significant fitness cost in P. aeruginosa and demonstrate how the molecular origins of the fitness cost of resistance can be dissected in a different biological context.
The political ecology of human-elephant relationships in India: encounters, spaces, politics
Keywords: India
Asian elephant
human geography
political ecology
biodiversity
posthumanism
postcolonialism

This thesis presents an examination of the political ecology of human-elephant relationships in India. Its overall aim is to revitalize the ecology that has been sifted out from the discipline. The thesis draws upon, and consequently develops, more-than-human geography through a sustained engagement of nature-society relations in a non-Western context.
The thesis has three broad objectives. First, to examine what more-than-human geography’s emphasis on non-dualistic forms of agency, could contribute to understandings of policy, planning and politics in conservation. Second, to examine the spatial dimensions of human-elephant relations and the social orderings of space which influence these relationships. The third objective of the thesis is to interrogate the politics of elephant conservation through a sustained engagement with diverse modes of human-elephant encounters and the socio-political assemblages with which they are entangled.
The thesis first deploys and develops the concept of ‘encounter value’ to account for the different forms of human-elephant encounters and how they contribute to the political economies of biodiversity conservation. The thesis then draws from a multi-sited ethnography examining both encounters and spaces of elephant conservation. It shows how elephants help forge connections across difference and the ways their geographies are reconfigured by global networks of conservation. The third empirical section has an implicit spatial dimension. It is concerned with writing a ‘more-than-human’ geography of landscapes, examining how humans and elephants cohabit with and against the grain of political design. Finally, the thesis examines politics as an ecology of relations, showing how human-elephant relations as well as social and political outcomes may be mediated by materials.
Modes of enquiry between these papers overlap. They offer critical insights into three themes that interface between political ecology and more-than-human geography. First, the thesis contributes to conceptualizing modes of human-animal encounters in a symmetrical fashion. It explicates the role of nonhuman agency as an organizing force in political economies of conservation. Second, it posits new understandings of the spaces of animals. This is developed in two ways: landscapes as dwelt, political achievements and as fluid spaces emerging through international networks of environmental governance. Third, the thesis ecologizes politics and goes beyond the humanist frameworks of political ecology. It fosters novel conversations between more-than-human geography and the postcolonial critique of political ecology in the context of human-elephant relationships. Taken together, the thesis offers up a concerted, symmetrical and novel approach to the study people’s relations with animals.
Simplified fixed pattern noise correction and image display for high dynamic range CMOS logarithmic imagers
Keywords: fixed pattern noise
high dynamic range
image sensors
CIELAB
tone mapping
colour quality
imaging
CMOS sensors
FPN modelling
colour error
logarithmic sensors
contrast sensitivity
EKV

Biologically inspired logarithmic CMOS sensors offer high dynamic range imaging capabilities without the difficulties faced by linear imagers. By compressing dynamic range while encoding contrast information, they mimic the human visual system’s response to photo stimuli in fewer bits than those used in linear sensors. Despite this prospect, logarithmic sensors suffer poor image quality due to illumination dependent fixed pattern noise (FPN), making individual pixels appear up to 100 times brighter or darker. This thesis is primarily concerned with alleviating FPN in logarithmic imagers in a simple and convenient way while undertaking a system approach to its origin, distribution and effect on the quality of monochrome and colour images, after FPN correction. Using the properties of the Human visual system, I propose to characterise the errors arising from FPN in a perceptually significant manner by proposing an error measure, never used before. Logarithmic operation over a wide dynamic range is first characterised using a new model; yi j =aj +bj ln(exp sqrt(cj +djxi)−1), where yi j is the response of the sensor to a light stimulus xi and aj, bj, cj and dj are pixel dependent parameters. Using a proposed correction procedure, pixel data from a monochromatic sensor array is FPN corrected to approximately 4% error over 5 decades of illumination even after digitisation - accuracy equivalent to four times the human eyes ability to just notice an illumination difference against a uniform background. By evaluating how error affects colour, the possibility of indiscernible residual colour error after FPN correction, is analytically explored using a standard set of munsell colours. After simulating the simple FPN correction procedure, colour quality is analysed using a Delta E76 perceptual metric, to check for perceptual discrepancies in image colour. It is shown that, after quantisation, the FPN correction process yields 1−2 Delta E76 error units over approximately 5 decades of illumination; colour quality being imperceptibly uniform in this range. Finally, tone-mapping techniques, required to compress high dynamic range images onto the low range of standard screens, have a predominantly logarithmic operation during brightness compression. A new Logr'Gb' colour representation is presented in this thesis, significantly reducing computational complexity, while encoding contrast information. Using a well-known tone mapping technique, images represented in this new format are shown to maintain colour accuracy when the green colour channel is compressed to the standard display range, instead of the traditional luminance channel. The trade off between colour accuracy and computation in this tone mapping approach is also demonstrated, offering a low cost alternative for applications with low display specifications.
Microcompartmentation of aldolase in Arabidopsis
Keywords: intracellular organisation
aldolase
microcompartmentation
enzyme moonlighting
actin
metabolons

Understanding the internal organization of cells from the molecular up to organelle level is a current challenge for biology if we are to better comprehend the mechanisms by which cellular processes occur. A prevailing view of the cell interior is that biochemical reactions and molecular movements are dominated by random diffusion. However, in addition to being compartmented into organelles, cells may well be organized at a finer level. Proteins may localise to specific areas within sub-cellular compartments, by associating with each other, the cytoskeleton and organelle membranes. Thus giving rise to distinct microcompartments. Considerable in vitro evidence exists for such interactions between enzymes and larger cellular components. This strengthens the idea that cells may be microcompartmented. However, little in vivo evidence supports this hypothesis, especially in plants. As a test-case for the concept of microcompartmentation this project investigated the sub-cellular distribution of the glycolytic enzyme fructose-bisphosphate aldolase in Arabidopsis thaliana; the ultimate aim being to establish whether it is microcompartmented in vivo and, further, to test the potential function(s) of such microcompartmentation.
Utrophin upregulation and microRNAs - two avenues of Duchenne muscular dystrophy therapy research
Keywords: DMD
utrophin
myopathy
microRNA
Duchenne
miRNA

Characterized by the severe progressive wastage of skeletal muscle, Duchenne muscular dystrophy (DMD) is a crippling X-linked recessive disease that is caused by the absence of the protein dystrophin. This thesis aimed to critically evaluate the potential of different therapeutic options to combat this disease. Utrophin is a paralogue of dystrophin. The Fiona mouse is an mdx (dystrophin-deficient) transgenic mouse that overexpresses the full-length utrophin protein in skeletal muscle, and various studies have shown that it does not display a dystrophic phenotype. However, these studies have only been performed on sedentary mice. In this work it is demonstrated that utrophin’s protective effect is partially diminished after a sustained period of exercise-induced stress, highlighting for the first time a functional difference between dystrophin and utrophin. This thesis also presents results of two mdx mouse drug trials testing the ameliorative effects of the administration of the drugs GW501516 and C1100, which show that treatment with both drugs results in partial amelioration of the dystrophic phenotype. GW501516 administration results in a beneficial fast-to-slow fibre type switch and an in vivo increase in utrophin protein levels. We have also shown that C1100 treatment results in a significant increase in utrophin A promoter activity in vitro, and the mechanism of action of this drug on this promoter has been deciphered. The global dysregulation of microRNAs in skeletal muscle of mdx and dko (dystrophin- and utrophin-deficient) mice was evaluated by microarray analysis to identify microRNAs involved in the dystrophic pathological cascades. The results of detailed expression analyses of miR-31, miR-206 and miR-503 are presented, and two therapeutically-relevant predicted targets of miR-503 were validated. Overall, this thesis evaluates the potential of different and possibly complementary therapeutic options to combat DMD.
Transnationalism and the Internet: the case of London-based Chinese professionals
Keywords: China
migration
transnationalism
Internet

This thesis examines the role of internet use in migrants’ participation in, and articulation of, rising Chinese modernity. It explores the ways in which transnational subjectivity is produced through this process. It investigates how migrants’ various uses of the internet construct and make sense of their connections with China. It demonstrates a new generation of subjectivity among Chinese transnationals that is tech-savvy, modern and triumphal – a subjectivity embedded in the exchange between the (macro) political economy of China’s rise and the (micro) everyday practices surrounding the internet.
This is an ethnographic study focusing on an emerging population within the broader Chinese diaspora; that is, mainland Chinese professionals who migrated for higher education and professional training in recent years as a result of China’s reform and economic power. This study locates its enquiries in three offline-grounded institutions – ethnic organisations, states and families. These institutions pre-date the internet but increasingly turn to the technology for transnational and local connections.
Regarding Chinese organisations, utilising the internet to build co-ethnic sociality is read as a symbolic practice that signals the users’ belonging to a technologically-advanced, mobile and wealthy sector within the broader idea of the Chinese community. On the role of the state, internet use provides new modes of migrants’ access to China’s state-led development projects, thus opening up new spaces for the state’s disciplinary power to be exercised. This digital governance is enabled by a discourse of Chinese triumphalism constructed by both the state and the migrants. Regarding families, the digitalisation of the gendered division of labour in transnational families provides evidence of the segmented nature of China’s digital modernity and disrupts the triumphal portrait of transnational modernity constructed among the elite-stratum migrants.
Overall, this study develops a dialogue between two literatures. On the one hand, it adds to diasporic internet studies by introducing an offline-grounded, geographically-informed approach and by bringing transnational modernity into its research agenda. On the other hand, it draws on Nonini and Ong’s (1997) theorisation of Chinese transnationalism as alternative modernity and further adds to this theorisation with a focus on internet technology and a discussion of the impacts of China’s rise. It contributes to human geography by revisiting a key concept in this discipline – transnationalism – with a discussion of the interweaving impacts of information technology and the geopolitical shift of China’s rising modernity.