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Reverberation Mapping of the Accretion Discs in the Quasars 3C 273 and 1H 2106-099
Get PDFThe main aim of this thesis is to perform the first accretion disc reverberation mapping analysis on the AGN 3C 273 and 1H 2106-099 using the modern reverberation mapping algorithms Javelin, PyceCREAM and PyROA. This is with the intention of obtaining useful physical insights into these AGN and to compare the performance of the algorithms. Through spectral, photometric and reverberation mapping measurements we find evidence to suggest the accretion disc spectrum in 3C 273 follows a power law with a slightly shallower exponent β ∼ 1 than expected from the approximated thin disc model (β = 4/3 ). However the difference does not seem very significant and good agreement was found with the more physically meaningful unapproximated thin disc model simulated with a boundary condition at the radius of innermost stable circular orbit. We therefore conclude 3C 273 likely conforms to the thin disc model and displays the ’accretion disc size problem’ with a scale ∼ 2 − 3 larger than expected. For 1H 2106-099, we found an unexpected discontinuity in the PyROA and Javelin lag estimates which is reflected in the spectrum and which we cannot identify with any specific contamination. Investigating the possibility that the discontinuity is anomalous, we obtain corrected Javelin and PyROA lag estimates in near perfect agreement with the thin disc model without an up-scaled accretion disc. Our PyceCREAM RM results also indicate that the discontinuity is anomalous but differ from PyROA and Javelin in suggesting the accretion disc in 1H 2106-099 is up-scaled by a factor ∼ 2. A secondary aim of the thesis was to investigate how the uncertainties on lag estimates returned by the algorithms depends on the length of the observing period and cadence of the light-curve data. Analysis on two dust reverberation mapping campaigns returned results which suggest that the length of the light-curve relative to the expected lag has a more significant effect on the size of the uncertainties than the cadence relative to the lag. We then estimate the optimum light-curve length to be ∼ 10× the expected lag and the optimum cadence to be ∼ 6× smaller than the expected lag which had associated lag uncertainties of ∼ 11% and ∼ 10% respectively
MEASUREMENT OF BREATH ACETONE IN THE DETECTION OF LOW CARBOHYDRATE AVAILABILITY FOLLOWING IMPLEMENTATION OF “TRAIN LOW” STRATEGIES
Get PDFEnhancing the metabolism of athletes can be achieved through the manipulation of nutrition and exercise variables. Muscle biopsies are currently viewed as the ‘gold-standard’ for assessing muscle glycogen levels of athletes. However, the process of obtaining a muscle biopsy is invasive and takes a considerable time to analyse. Following research that has implemented muscle biopsies, it has been suggested that an acute reduced carbohydrate intake in conjunction with a suitable training intensity (known as “training low”) has shown to elicit conducive metabolic adaptations to increase the sustainability and production of adenosine triphosphate (ATP) to support endurance athletes. The overarching purpose of this research was to establish and refine a suitable protocol, which could be employed to analyse the effectiveness of a number of “train low” strategies at eliciting low carbohydrate availability in endurance athletes. Six key aims were identified to guide the research, which focused on the integration of chemistry and sports science equipment, identifying the most effective sequence to collect the measurements required, and comparing and understanding two breath acetone (BrAce) detectors for assessing carbohydrate availability. This thesis presented a methodological-development study to address the purpose and aims through a series of four pilot studies. The two BrAce detectors included a Cavity Enhanced Laser Induced Fluorescence (CELIF) prototype (made by the Chemistry Department at Durham University) and a Ketonix® BrAce detector, which is currently in the breath analyser market. In addition to the BrAce detectors, other metabolic measurements included capillary blood glucose, betahydroxybutyrate and gas analysis (i.e., respiratory exchange ratio). The pilot studies concluded with an experimental pilot, which involved an endurance athlete (male, ultra-endurance, running; age: 38 years; stature: 1.76 m; body mass: 66.1 kg), who followed the agreed protocol. Taking the range of measurements sequentially rather than in parallel
was the most effective, with the CELIF BrAce concentrations reflecting the values of the accompanying metabolic measures more than the Ketonix®, with the Ketonix® providing a wider variance of measurements within and between participants. The participant in the experimental trial was unable to complete the exercise protocol after following the “train low” strategies. Overall, the agreed protocol worked effectively, with some revaluation required for elements of the equipment and protocol. The CELIF BrAce detector provided an indication that it detects carbohydrate availability more effectively than the Ketonix®. However, further refining and development is required to improve the prototype’s effectiveness of detecting low carbohydrate availability
Precision QCD corrections to gluon-initiated diphoton-plus-jet production at the LHC
Get PDFIn this thesis, we present recent advances at the precision frontier of higher-order quantum chromodynamics (QCD) calculations. We consider massless two-loop five-point amplitudes, with a particular focus on diphoton-plus-jet production through gluon fusion. We build a library of infrared functions up to at most next-to-next-to-leading order (NNLO) in QCD, which can be used to validate amplitudes and construct counterterms in subtraction schemes at NNLO. We review progress in the novel use of machine learning technology to optimise the evaluation of amplitudes in hadron collider simulations. We present the full-colour virtual QCD corrections to diphoton-plus-jet production through gluon fusion, discussing the new techniques developed to calculate these non-planar two-loop amplitudes. We use these amplitudes to compute the next-to-leading QCD corrections to the differential cross sections of diphoton-plus-jet production through gluon fusion at the Large Hadron Collider. We also present the leading-colour double-virtual corrections to hadronic trijet production. All derived amplitudes are made available in a public implementation that is ready for further phenomenological application
Investigating the sustained impact of the physical cellular microenvironment on the structure and function of a hepatocellular carcinoma cell line.
Get PDFMechanotransduction defines the functional activity of cells by altering gene expression in accordance with cellular structure. With this in mind, a novel in vitro model has been developed where cells are ‘primed’ to a three-dimensional (3D) phenotype through growth on a biologically inert 3D substrate before liberation and reseeding into a secondary culture. To characterise this protocol, the structural and functional effects of 3D priming were evaluated on the HepG2 hepatocellular carcinoma cell line, frequently used for in vitro liver research on drug discovery and pathology.
It was found that through using a 3D priming model, cells adopted a mechanical and functional memory based on the historical physical microenvironment. HepG2 cells primed in 3D demonstrated altered cytoskeletal organisation and cell morphology after reseeding, with cell populations more readily forming 3D structures compared to cells reseeded from conventional two-dimensional (2D) substrates. Global gene expression was significantly altered in the priming model, with enrichment of mechanical and structural genes occurring in 2D HepG2 cells compared to enrichment in key genes involved in hepatic metabolism and biosynthesis in the 3D primed HepG2 cells. 3D priming also resulted in enhanced production of the liver specific biomarkers albumin and urea; even within secondary 3D spheroid cultures. Metabolic activity was significantly altered through priming, with the 3D priming model showing decreased sensitivity to xenobiotic toxicity, though this difference balanced out in the secondary models.
Overall, this study has shown that changing the substrate geometry impacts directly on cell structure and results in an altered transcriptional state in HepG2 cells that gives rise to a more physiologically relevant phenotype that is sustained even after enzymatic and mechanical disruption. This holds potential for improving the functionality of in vitro models and further elucidates the role of mechanotransduction in directing cell biology
'Rome's Immortal Fair': The Roman Matrona in the long eighteenth century imagination
Get PDFThis thesis explores receptions of Roman matronae in France, Britain and its American colonies during the Age of Revolutions. Roman matronae, were towering figures in the eighteenth-century political imagination. Heroines generally from the period of the Roman Republic, matronae were upheld in ancient histories and in later European culture as ‘female worthies’, exemplary monuments to stoicism, self-sacrifice, patriotism, and civic bravery. Invested with civic significance as wives, mothers and sometimes as civic agents in their own right, Roman matronae were, ancient worthies with an explicitly political inflection. Though championed in eighteenth-century culture as models for female political activity, the cultural power of the Roman matrona in this period has hitherto escaped scholarly analysis, obscured by more recent assumptions concerning the ‘hyper-masculine’ coding of the ‘idea of Rome’, and particularly Roman Republicanism, in eighteenth-century civic discourse. Through exploration of Roman matronae in eighteenth-century visual and material culture, this thesis seeks to complicate such assumptions and shed new light upon the important place ‘ideas of Rome’, occupied in the aesthetic, political, and intellectual identities of British and French women in the age of Enlightenment and Revolutions. First charting the rise of the Roman matrona in the literary public spheres of seventeenth-century France and eighteenth-century Britain, the chapters of the thesis in-vestigate the cultural and political work performed by the Roman matron in electoral politics, Republican and proto-feminist philosophy, and in the dramaturgy of the French Revolution, to demonstrate how matronae were made conduits for female virtue, patriotism, feminism, and classical erudition. In so doing, this thesis also reveals how women themselves engaged in dynamic processes of classical reception to claim space, agency, and citizenship within their political communities during the long eighteenth century
A novel role for PRC2 activity in light signalling in Arabidopsis thaliana
Get PDFLight is the major regulator of plant development, controlling a number of key stages throughout the plant life cycle. One of these is the transition from skotomorphogenesis to photomorphogenesis in seedlings upon exposure to light. Perception of light via a suite of photoreceptors initiates a massive reorganisation at the transcriptional, translational and post-translational levels across the seedling. In recent years, increasing evidence has also been presented showing epigenetic changes also play a crucial role in this process. The work in this thesis seeks to contribute to this growing field by identifying that the Polycomb Repressive Complex 2 (PRC2) plays a key role in photomorphogenesis via the deposition of H3K27me3, mediated by the histone methyltransferase CURLYLEAF (CLF).
Phenotypic and genetic analysis shows that CLF activity is upregulated by blue light in a CRY1-dependent manner, and that loss of CLF leads to elongated hypocotyls – a classic phenotypic trait which has been long used to identify deficiencies in light signalling. RNA-seq and ChIP-qPCR analysis indicates that CLF inhibits hypocotyl elongation via the deposition of the silencing chromatin modification H3K27me3 at expansins and XTH genes. It is also shown that CLF further contributes to the enhancement of auxin signalling in cotyledons via the H3K27me3-mediated silencing of AUX/IAA and GH3 genes. Additional phenotypic analysis indicates that CLF also plays a role in other auxin-regulated processes such as phototropism. Finally, a candidate interaction is identified between CLF and the skotomorphogenesis-promoting transcription factor PIF4, indicating an intriguing possible mechanism for CLF regulation during light responses
Newly Created Children of God: Adoption and New Creation in the Theology of Paul
Get PDFThe main thesis of the present study is that Paul’s use of υἱοθεσία (Rom 8:15, 23; 9:4; Gal 4:5) can be best explained by the concept of new creation understood within the Jewish context. In other words, Paul uses the metaphor of “adoption” within the frame of the new creation in Christ, and this affects both the form and content of the adoption metaphor. The concept of new creation in υἱοθεσία in Rom 8:15 and Rom 8:23 is closely related to the themes of “Spirit” and “resurrection” based on their allusions to Gen 2:7 (via allusions to Ezek 36–37) and Gen 3:16-19 respectively. In Rom 9, Paul uses the adoption metaphor to describe God’s election of Israel not according to any of their qualifications but according to God’s calling and mercy. This indicates that the gift of υἱοθεσία has to be confirmed and fulfilled in Christ in the context of new creation. Similarly, Paul’s use of υἱοθεσία in Gal 4:5 has a connection with the new creation (καινὴ κτίσις) in Gal 6:15, in terms of a new identity in Christ regardless of ethnicity, social status, and gender (cf. Gal 3:28). Not only Gal 3:28’s famous allusion to Gen 1:27 but also the Adamic narrative framework in Gal 4:1-7, which I will argue in this thesis, strengthen the new creation context of Paul’s use of the adoption metaphor in Gal 4. In order to demonstrate the close relationship between Paul’s adoption metaphor and the concept of new creation, I will investigate the concept of new creation in Second Temple Jewish writings and in Paul (Part I of this thesis: chapters 2–4) and analyse Paul’s use of υἱοθεσία in light of new creation (Part II of this thesis: chapters 5–7).
Although there has been a great deal of research on Paul’s use of υἱοθεσία and the concept of new creation in Paul, no study has paid attention to the close relationship between them and what this relationship means for the shape of Pauline theology. For example, recent studies of ethnicity in Paul—the so-called “Radical New perspective on Paul” or “Paul within Judaism”—often appeal to the Abrahamic sonship or the divine sonship in Romans and Galatians, but the sense of new creation—in terms of discontinuity, incongruity, and divine intervention in Christ—is virtually absent in their arguments. In the present study I will attempt not only to demonstrate the close relationship between Paul’s use of υἱοθεσία and the new creation motif but also to show how this relationship helps us to gain a better understanding of Pauline theology through a dialogue with the “Paul within Judaism” school of scholars
Community Response to Flood Disaster: A Case Study of Flooding in Penang, Malaysia
Get PDFIn November 2017, Penang Island, Malaysia, experienced the heaviest rainfall ever
recorded on the island. The city is very low lying, has undergone massive development
in the last three decades and is built predominantly of high-rise buildings on steep
slopes with land-reclamation megaprojects. Rapid urbanisation is another serious
environmental issue, leading to forest clearance, which means the area which can act
as a sponge to absorb excess water gets continually smaller; as a result, the city flooded.
There were several other flooding incidents across Malaysia in 2016-2017, but Penang
was the worst-affected area, recording 51 flash floods between January 2016 and midOctober 2017. As a consequence, a large proportion of the 220,000 homes in the city
were flooded.
This research demonstrates a comprehensive investigation of community resilience and
the factors affecting vulnerability at the household and organisational levels via the
experience of flood response in Teluk Kumbar, Penang Island. Over recent decades,
the increased incidence of flood disasters has been accompanied by a dramatic
proliferation of human inequalities, economic damage, environmental degradation,
recovery costs, institutional vulnerability, and political processes.
This research uses a multi-method approach in which the qualitative and quantitative
data were conducted sequentially. The data set comprises in-depth semi-structured
interviews with 28 experts to examine the construction of flood management
knowledge and its relation to decision-making. Additionally, 100 individuals, including
both male and female, were surveyed through a questionnaire, and 29 of them
participated in six separate focus-group discussions. Six months of fieldwork allowed
naturally occurring talk, unstructured interviews, and photovoice data related to locals'
daily lives to understand their social behaviours when responding to flooding
emergency times.
This dissertation is an endeavour to capture people's perception and response to
measure the effectiveness of the community's coping strategies, social capital, adaptive
capacity and identify factors that influence vulnerability to flooding hazard as a matter
of exposure to risk and susceptibility. One of the main stated objectives has emphasised
the necessity of improving community resilience regarding proactive preparedness and
their response to flood mitigation initiatives.
According to the study's findings, there is a strong correlation between people's local
knowledge, their social capital and how they developed their coping capacity,
preparedness and decision-making. In particular, the thesis centered on the absence of
local people's voices in local participation because of the political involvement and
bureaucratic nature. In fact, it was also clear that it’s negatively impact effective
emergency flood management and the response capacity of local residents.
Overall, results revealed that community preparedness should be well articulated with
the involvement of the local people that are ready to deal with any eventualities.
Specifically, this thesis uses the 2017 flood events to re-examine the theoretical and
conceptual understanding of progress in integrating resilience capacity building and
ongoing attention on flood mitigation in flood disaster preparedness at the community
level. Further, this research makes a practical and significant valuable contribution for
local government - public institutions (e.g. NADMA, Malaysia National Security
Council, Penang City Council), decision-makers, nonprofit volunteer organisations,
local community groups and relevant significant stakeholders, including professional
practitioners related to flood management and recovery
Predictive maintenance modelling on offshore wind turbines: combining big data with expert knowledge
Get PDFThe downward price pressures on wind power in the past fifteen years have spurred research into predictive maintenance modelling on wind turbines. This research explored fault prediction modelling using unprecedented quantities of wind turbine SCADA data, work-order data and expert knowledge.
This thesis details the development of prediction models for eight fault case studies. In each case study, methodologies for applying large wind turbine operational datasets to model development were explored and implemented.
These datasets were used to develop enhanced class labelling approaches for training datasets. Developed models underwent extensive validation testing using the large number of example faults available. These approaches were consolidated into a recommended framework for developing future models.
The developed models were implemented into the operational strategies of eighteen offshore wind farms. Hundreds of instances of site feedback from site technicians were used to determine an accurate picture of performance metrics such as lead time and precision.
The research established that interpretable models, developed through observation and rule extraction approaches, can be applied to multiple wind turbines across wind farms without compromising performance. Recommended training dataset sizes for producing robust classifiers were determined from experiments on two case studies
Improving the Logarithmic Accuracy of the Angular-Ordered Parton Shower
Get PDFMonte Carlo event generators are a key tool for making theoretical predictions that can be compared with the results of collider experiments, our most
accurate probes of fundamental particle physics. New developments in the way parton shower accuracy is assessed have led us to re-examine the accuracy of the angular-ordered parton shower in the Herwig 7 event generator, focussing on the way recoil is handled after successive emissions. We first discuss how the evolution variable is defined in the Herwig angular-ordered shower and how the choice of this definition determines the recoil scheme. We then show how the recoil scheme can affect the logarithmic accuracy of final-state radiation produced by the algorithm. As part of this investigation we consider a new interpretation of the evolution variable intended to mitigate problems with previous iterations of the shower. To test this, simulated events for each scheme are compared with experimental data from both LEP and the LHC. Next we extend our analysis to initial-state radiation and perform the same process of assessing the logarithmic accuracy of different interpretations of the evolution variable. This time, we compare simulated events for each scheme with LHC data for the vector boson production. Additionally, we consider the impact that the choice of NLO matching scheme has on the accuracy of these simulations, with reference to the same LHC data
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