text: DSpace Collection: http://hdl.handle.net/2381/8806 2015-10-10T12:32:08Z A bayesian approach to the study of dark matter in disk galaxies http://hdl.handle.net/2381/33167 Title: A bayesian approach to the study of dark matter in disk galaxies Authors: Hague, Peter R. Abstract: Studies of the rotation of disk galaxies have long been used to infer the presence and distribution of dark matter within them. Here I present a new Markov Chain Monte Carlo (MCMC) method to explore the extensive and complex parameter space created by the possible combinations of dark and luminous matter in these galaxies. I present exhaustive testing of this method to ensure it can retrieve dark matter halo parameters from artificial data, and apply it to real galaxies from The HI Nearby Galaxy Survey (THINGS) and other sources. The results of these studies can shed some light on how disk galaxies form and evolve. Chapters 1 and 2 provide background for the physics and statistical methods respectively. Chapter 3 shows the testing of the MCMC method on artificial data, and applies it to DDO 154 to find a more robust constraint on the inner log slope than previous methods. Chapter 4 applies this method to a broad range of galaxies taken from the THINGS survey, constrains their physical properties, and presents a simple model of feedback to compare with. Chapter 5 applies the method to M33, mapping a degeneracy between the log slope of the dark matter halo and the mass-to-light ratio, that excludes the combination of a cored halo and a light stellar disk. Chapter 6 extends the MCMC method to an earlier stage of analysis by marginalising over the parameter space of possible disk models for simulated galaxies. Chapter 7 presents conclusions and discusses future work that can lead on from this thesis. 2015-10-01T15:59:29Z Absorption Line Variability in BALQSOs and NGC 4151 http://hdl.handle.net/2381/33166 Title: Absorption Line Variability in BALQSOs and NGC 4151 Authors: Wildy, Conor Abstract: Blueshifted AGN absorption lines indicate outflowing material from the central engine. Many repeat spectral observations of AGN have observed variability in the shape and strength of these lines, however there is no scientific consensus regarding the dominant mechanism which drives this variability. The main purpose of this thesis is to investigate this mechanism in a sample of BALQSOs and a Seyfert 1 galaxy. The BALQSO sample consists of 50 quasars, in which we test the dependence of broad absorption line variability on several variables. To do this a novel technique is used (Non-negative matrix factorisation) to reconstruct the entire emission profile, allowing accurate measurement of variability even in cases of absorption line overlap with the corresponding broad emission line. No significant correlations between variability and any of the investigated properties are found. The lack of luminosity correlation suggests ionisation changes do not play a dominant role in the variability of the BALQSO population. The most variable BALQSO in the 50 quasar sample, SDSS J113831.4+351725.3, shows extraordinary BAL variability, with one C IV BAL lying outside the random walk model which accurately predicted the BAL behaviour in a large BAL study. Co-ordinated BAL changes in this object, despite being separated by thousands of km s−1, together with results of photoionisation simulations and the behaviour of the continuum, strongly suggest that the variability mechanism is ionisation fraction changes driven by variations in the input ionising continuum. The Seyfert 1 galaxy NGC 4151 is noted for its continuum variability, however its absorption line variability is less well studied. Examination of the variability of metastable helium absorption lines, which are sensitive to high column densities, suggests a crossing-clouds scenario in which changes to the line-of-sight covering fraction occur, thereby driving spectral changes. Photoionisation calculations suggest a mass outflow rate which is too small to result in galaxy feedback effects. 2015-10-01T15:54:30Z The Development and Treatment of Strabismic Amblyopia http://hdl.handle.net/2381/33165 Title: The Development and Treatment of Strabismic Amblyopia Authors: Maconachie, Gail Dorothy Elizabeth Abstract: Background: Strabismus development is a complex process involving various parts of the visual system. This complexity is increased by the presence of numerous subtypes. Although research has shown strong genetic and environmental components it is not yet clear if there are stronger associations with particular subtypes. In addition, the association between strabismus and retinal development and its limitation on visual outcome, in combination with other factors such as compliance to treatment, has not yet been explored. Methods: Strabismic subjects were recruited to four areas to assess the development and treatment of strabismic amblyopia. Genetic and environmental factors were systematically identified within the literature and through strabismic pedigrees. The influence of strabismic development on the retina was assessed using optical coherence tomography (OCT) in strabismic infants compared to healthy controls. OCT and electronic monitors were used to investigate causes of poor outcomes after amblyopia treatment. Results: Systematic reviewing of the literature revealed strong associations between strabismus and various environmental and genetic factors. By observing the inheritance of strabismus through pedigrees it was observed that accommodative forms of esotropia had a stronger association with inheritance than other subtypes. The effect of strabismus on retinal development revealed delayed or abnormal changes within particular layers of the retina. These defects were observed in both eyes of strabismic subjects and were sustained in subjects who failed to reach successful outcomes after treatment. In addition, through using electronic monitors, compliance to both glasses wearing and occlusion were significantly correlated to visual outcomes. Conclusion: This thesis continues to support growing evidence that both genetic and environmental factors play a role in strabismus development. Its development also has retrograde effects on the visual pathway in particular the retina, which is sustained unless treatment is successful. In addition, compliance to treatment has shown to be vital in obtaining a successful outcome. 2015-10-01T15:42:52Z Investigation into the effect of refractivity on propagation at uhf and vhf frequencies – modelled and experimental analysis http://hdl.handle.net/2381/33163 Title: Investigation into the effect of refractivity on propagation at uhf and vhf frequencies – modelled and experimental analysis Authors: Alam, Imtiaz Abstract: The goal of this research was to use weather parameters to compute refractivity variation of the atmosphere that can be used to predict refractivity distribution in the first kilometre of the atmosphere over the English Channel for UHF and VHF propagation and to understand the influence of meteorology on propagation. Different refractivity profiles are constructed based on meteorological data taken from the UK Meteorological Office in order to investigate their effects on wave propagation. The hourly experimental path loss between the transmitter and receiver obtained from the experimental setup comprising of two UHF and two VHF communication links are investigated for a period of one year. The experimental setup comprises of long and short trans-horizon paths (140 km and 50 km) having a transmitter located on Jersey and receivers on Portland and Alderney. In order to investigate the characteristics of refractivity and its impact on wave propagation, a propagation model is developed in MATLAB using parabolic equation method. The model is used to get an hourly modelled path loss corresponding to the experimental path loss for four communication links of UHF Portland, UHF Alderney, VHF Portland and VHF Alderney. The correlation between the modelled path loss and experimental path loss is presented for refractivity distribution recommended by the ITU and for that of a standard atmosphere. The simulated and experimental results showing the influence of evaporation duct upon path loss for frequencies of 240 and 2015 MHz is also included. The results obtained by using the standard atmospheric refractivity profile were a better fit to the experimental observations than the ITU recommended values for some of the investigated links. It is also inferred that evaporation ducts exist up to a height of 10 m for the short path at both frequencies and up to a height of 30 m for the long path at VHF but not at UHF. 2015-10-01T15:37:12Z The palaeontology of Bering sea foraminifera from the late quaternary http://hdl.handle.net/2381/33161 Title: The palaeontology of Bering sea foraminifera from the late quaternary Authors: Oluyemi, Aturamu Adeyinka Abstract: The taxonomy of benthic foraminifera recovered from 160 core samples over depth 20.59 m and representing the past ~597 Kyr (sedimentary deposit of the Tarantian and Ionian stages) at Bowers Ridge, Bering Sea IODP site U1342, includes some 52 species from 41 genera and 22 families: these species are given formal taxonomic treatment with detailed illustration. A further 16 species are discussed in open nomenclature. Foraminifer assemblages are dominated by species of Takayanagia delicata, Uvigerina bifurcata, Islandiella norcrossi and Alabaminella weddellensis accounting for more than 58 % of all specimens recovered. In addition to their taxonomic identification, this study interrogates the relationship between benthic foraminifera and interpreted changes in oxygen concentration and productivity during a series of late Quaternary glacial– interglacial cycles at site U1342. In particular, the species Bolivina spissa (Cushman) – thought to record changes in seabed oxygen level, shows no correlation between test pore density and interpreted bottom water oxygen level (BW-O2), suggesting that oxygen is not the sole driver influencing the distribution and morphology of this species. Further assessment of the total foraminiferal assemblages at site U1342 - using the sedimentological context and the proportion of deep infaunal species as a proxy for low oxygen conditions at the seabed, and shallow infaunal species as a proxy for a welloxygenated seabed, identify eight broadly defined temporally successive benthic foraminiferal intervals through the sampled core. Three of these intervals, between depths 0 - ~5.40, ~ 6.50 - 9.00 and ~16.90 - 18.67 m-CCSF, signal a well-oxygenated sea bed, whilst the other five intervals suggest increased phytodetritus flux to the seabed, coupled with variations in seabed oxygen level. In general, there is no clear connexion between these intervals and the glacial-interglacial oscillation at the site during the past ~597 ka, suggesting that ecological influences on foraminiferal distribution at Bowers are complex. 2015-10-01T15:21:58Z Regulation of L-Type Ca2+ Channels by Nitric Oxide Signalling in Guinea Pig Ventricular Myocytes http://hdl.handle.net/2381/33158 Title: Regulation of L-Type Ca2+ Channels by Nitric Oxide Signalling in Guinea Pig Ventricular Myocytes Authors: Weli, Sardar Mohammed Abstract: Nitric oxide (NO) is constitutively generated by cardiac myocytes and has important roles in cardiac function, including modifying L-type Ca2+ currents (ICa,L). The precise nature of this modification remains elusive with NO reported to increase, reduce or have biphasic effects on ICa,L. Here I explored the effects of NO signalling on ICa,L in both active period and resting period myocytes recorded from guinea pig ventricular myocytes using the perforated whole-cell switched voltage-clamp technique to maintain intracellular signalling pathways. Both cGMP-dependent and S-nitrosylation pathways were investigated. Isoprenaline (100 nM) significantly increased peak ICa,L by about two fold. Subsequent application of NO, using the NO donor SNAP, significantly decreased this enhanced ICa,L but had little effect on basal ICa,L. In contrast to these results obtained from active period myocytes, NO did not inhibit isoprenaline enhanced ICa,L in resting period myocytes. In active period myocytes NO inhibition of isoprenaline enhanced ICa,L was maintained in the presence of ODQ (1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one), a soluble guanylyl cyclase (sGC) inhibitor. Direct activation of sGC or peripheral guanylyl cyclase independently of NO by BAY 60-2770 or ANP respectively, however, gave results similar to those observed with NO; although in some cells, BAY 60-2770 did not reduce isoprenaline enhanced ICa,L. Thus direct activation of sGC mimics the effect of NO, yet inhibiting sGC did not abolish NO reduction of isoprenaline enhanced ICa,L. These results suggest that NO modulates ICa,L through more than one mechanism. To investigate the S-nitrosylation pathway, denitrosylation was inhibited using N6022, a blocker of S-nitrosoglutathione reductase, an enzyme involved in denitrosylation. This treatment, either completely abolished or slowed significantly the rate of development of isoprenaline enhancement of ICa,L in cells exposed previously to NO. In conclusion, NO inhibition of isoprenaline enhanced ICa,L involves at least two signalling pathways; a cGMP-dependent and the S-nitrosylation pathway in active period myocytes. 2015-10-01T15:01:59Z Reassessing the long chronology of the penannular brooch in Britain: exploring changing styles, use and meaning across a millennium http://hdl.handle.net/2381/33157 Title: Reassessing the long chronology of the penannular brooch in Britain: exploring changing styles, use and meaning across a millennium Authors: Booth, Anna Louise Abstract: Penannular brooches are a simple form of dress fastener used in Britain from the late Iron Age, through to the Roman and Early Medieval periods. This thesis represents the first full study of their British development for fifty years. The catalogue of penannulars originally compiled by Elizabeth Fowler in the late 1950s has been more than doubled, allowing a thorough re-analysis of chronological variation and continuity in stylistic development, distribution, use and deposition. This has been carried out via broad analysis of the penannular database and two regional case studies looking at South-West England and Yorkshire and North Lincolnshire, the two areas where penannulars were concentrated throughout their chronology. Many previous studies have focused only on the later penannular types, leading to an unbalanced approach dominated by the preoccupations of early medieval archaeology. This has created the perception that penannulars had a simple evolutionary development that contributed to the straightforward survival of a 'Celtic' culture in some regions during the Roman period and beyond. To counterbalance this, analysis here has particularly focused on the earlier end of the penannular chronology. As a result an alternative picture is presented, of a highly complex development influenced by Continental parallels, which stands in deep contrast to the simplistic sequences proposed in most previous studies. The ever increasing corpus of theoretical work on bodily adornment has also been drawn on, enabling a more nuanced approach that moves us away from the idea that appearance is just an external manifestation of a single, static form of identity and instead recognises that it plays a vital role in an active and continual process of forming and maintaining multiple, complex, overlapping and sometimes opposing identities. 2015-10-01T14:50:49Z Wrist partial arthrodesis or other motion preserving surgery for degenerative wrist disease: Prospective comparative assessment of grip strength, range of motion, function and disability. http://hdl.handle.net/2381/33156 Title: Wrist partial arthrodesis or other motion preserving surgery for degenerative wrist disease: Prospective comparative assessment of grip strength, range of motion, function and disability. Authors: Singh, Harvinder Pal Abstract: Traumatic osteoarthritis of the wrist is a disabling disease that affects middleaged active adults in the prime of their working life. I set out to assess wrist function and disability in patients with traumatic wrist osteoarthritis before and after surgery. I measured wrist range of motion with flexible electrogoniometer, grip strength with force-time curves using dynamometer, hand function with timed Sollerman hand function test and patient-reported outcome. I first developed these techniques in normal volunteers and then extended them to patients with wrist osteoarthritis before surgery and after four-corner fusion, three-corner fusion, total wrist fusion, and proximal row carpectomy. I used flexible electrogoniometry to generate circumduction curves to measure range, rate and rhythm of circumduction of the wrist. It showed that there was no difference in range of motion parameters in patients with wrist osteoarthritis before surgery and after four-corner fusion and three-corner fusion. Proximal row carpectomy provides better flexion-extension and poorer radio-ulnar deviation than four-corner fusion. Three-corner fusion allows better rate and rhythm of movements in flexion and ulnar deviation compared to four-corner fusion. Grip strength was measured with dynamometer to generate force time curves to measure sustainability of grip. There was no difference between our groups with wrist osteoarthritis before surgery and after wrist fusion, four-corner fusion or three-corner fusion. I developed the Timed Sollerman hand function test by measuring the time taken to complete each of the tasks without summarisation into a 5-point scale. It showed that volunteers completed the tasks quicker with the dominant hand than with the nondominant hand. Women took less time to complete the tasks in the 30-40 years age group than women in the 20-30 years age group and beyond 40 years. The patients with PRC completed the different activities of daily living quicker than the 4CF patients, except for activities requiring wrist torque strength. 2015-10-01T14:44:19Z Investigating the effects of curcumin and resveratrol on pancreatic cancer stem cells http://hdl.handle.net/2381/33155 Title: Investigating the effects of curcumin and resveratrol on pancreatic cancer stem cells Authors: Karim, Karzan Khowaraham Abstract: Anti-proliferative and cancer stem-cell targeting abilities of curcumin and resveratrol individually have been shown in different cancers. This project aimed to assess the activity of these compounds, alone and in combination in pancreatic cancer cell lines (PCCLs) and stellate cells. Anti-proliferation assays were performed for curcumin and resveratrol alone and in combination, combined with end point markers of activity including apoptosis and cell cycle arrest. Pancreatic cancer stem cell populations were defined using the cell surface markers CD44, CD24, ESA, CD133, ALDH-1 activity or sphere forming ability, and finally Nanog expression was assessed. The intracellular uptake of curcumin and its metabolites was analysed by HPLC. The PCCLs were more sensitive to curcumin than resveratrol, and combinations of these compounds showed anti-proliferative efficacy through apoptosis and cell cycle arrest at low, clinically achievable concentrations (CACs) in 2 out of 4 cell lines. Capan-1 cells exhibited the highest sensitivity to curcumin, which was able to enhance the effectiveness of resveratrol treatments in targeting cancer stem-like populations. Spheroid growth was significantly inhibited by curcumin and resveratrol combinations in Capan-1 cells, correlating with decreased ALDH1 activity and Nanog expression. In human pancreatic cancer tissue, various stem-like populations were identified based on expression of ALDH1 or CD24+/CD44+, which may provide a suitable target in vivo. Capan-1 cells metabolised curcumin to detectable amounts of curcumin glucuronide. However, curcumin metabolites did not show any significant activity at CACs. Curcumin alone may have activity against pancreatic cancer stem cells, and enhances efficacy at low concentrations when in combination with resveratrol. Capan-1 cells are able to internalise curcumin, and this cell line exhibited the greatest sensitivity to treatment. Overall, the results suggest that curcumin and resveratrol warrant further investigation as combination therapies for targeting cancer stem-like cells and stellate cells responsible for the dense stroma observed in pancreatic cancer. 2015-10-01T14:35:59Z Exploring the problematic nature of GCSE examining in Economics and Business: Assessing troublesome knowledge, threshold concepts and learning http://hdl.handle.net/2381/33153 Title: Exploring the problematic nature of GCSE examining in Economics and Business: Assessing troublesome knowledge, threshold concepts and learning Authors: Ashwin, Andrew Kenneth Abstract: This thesis focuses upon assessment of learning at General Certificate of Secondary Education (GCSE) level. Approaches to learning, lecturers' conceptions of teaching, students' conceptions of learning, threshold concepts and troublesome knowledge have all been the focus of research at higher education but there has been limited work into the relevance of these fields to learning prior to higher education. This thesis surveys the research in higher education and applies some of the concepts to assessment, teaching and learning at lower levels of the education hierarchy. It looks at the extent to which students at GCSE level might be expected to begin the journey of thinking in the subject in the fields of economics and business. Teachers are a key influencer of assessment outcomes at GCSE level but their approach to teaching and their conception of learning may be influenced by the assessment framework in which they are operating. Analysis of student responses to examination questions, the extent to which teachers at this level can agree on evidence of learning and what an assessment is designed to achieve and teachers' conceptions of learning will be studied at GCSE. The results of this research suggest that a reconceptualisation of the assessment objectives, which frame the specifications at this level and provide a focus for curriculum development, could influence the way students are taught and the way in which teaching and learning programmes are put together. Such a change could help to reduce the asymmetry between students and teachers and encourage teaching and learning which helps students to 'think in the subject' and champion deep approaches to learning. 2015-10-01T14:27:48Z Designing for the Post-Millennials: What assumptions are made by staff in museums about child digital literacy when designing digital interactives? http://hdl.handle.net/2381/33074 Title: Designing for the Post-Millennials: What assumptions are made by staff in museums about child digital literacy when designing digital interactives? Authors: Hetherington, Amy Kristine Abstract: This research seeks to examine issues surrounding digital literacy discourse and its place within the museum. Using the design of digital interactives as an example, it asks what assumptions museums have made about child digital literacy, and how these assumptions have changed over the last fifteen years. The study proposes a new application of digital literacy theory that can usefully differentiate between what it categorises as realistic and optimistic perceptions of child digital literacy, and then uses this theory to understand how museums view their child visitors and how they design for them digitally. The research adopts a historical approach in its methodology to look at the design processes and digital interactives over the last fifteen years, in three museums of digital interactive design. The thesis explores what it characterises as the 'four-step' design process (from user-centred design theory) to help it uncover where assumptions are made and what effect this has had on the resulting interactives. The intention has been to make a case that when designing in-gallery digital interactives for children, the museums tend to adhere more to an optimistic discourse of digital literacy than one that might be seen as realistic, and that furthermore, this is a tendency that has persisted over the course of many years of design in three English museums. The significance of the thesis rests in the appropriation of digital literacy theory to form a greater understanding of museums' perception of their young visitors, by uncovering the influences on staff in their digital interactive design considerations. Description: Some images removed due to copyright. 2015-09-21T13:22:49Z Causes of Brain Injury Associated with Cardiac Interventions http://hdl.handle.net/2381/33073 Title: Causes of Brain Injury Associated with Cardiac Interventions Authors: Patel, Nikil Abstract: Background& Objective: Brain injury after cardiac surgery is a serious concern for patients and their families. Thousands of air bubbles enter the cerebral circulation during cardiac surgery, but whether these are harmful to the brain and impact adversely on cognition remains subject of speculation. The purpose of this study was to use MRI to characterise new and pre-existing cerebral ischaemic lesions in patients undergoing cardiac surgery, and to test whether the accumulation of new lesions adversely affects cognition. This study also draws upon recent advances in intra-operative bubble sizing to investigate whether high volumes of macro-bubbles have potential to result in new MRI lesions or increased risk of cognitive decline following surgery. Methods: The burden of pre-existing versus new ischaemic lesions was quantified based on analysis of 3T MR images and compared with the results of cognitive testing. Intraoperative Doppler ultrasound recordings were used to estimate the number, volume and diameters of bubbles entering the middle cerebral artery during surgery for comparison with MRI and cognitive outcome. Results: Post-operative lesions were identified in 31% of patients. Patients with pre-existing lesions were 10 times more likely to receive new lesions after surgery. Forty six percent of patients experienced postoperative cognitive decline, which was independent of whether new lesions were present. Intra-cardiac patients received over 16 times the total volume of air, 7 times as many macro-bubbles, 5 times as many emboli following aortic cross-clamp removal, and over twice as many emboli overall than CABG patients, but there were no significant differences in MRI or cognitive outcome. Conclusions: New MRI lesions and high numbers of intra-operative macro-bubbles are common during cardiac surgery, but we found no evidence of any adverse effect on cognition. 2015-09-21T13:14:13Z Imaging China: China's cultural diplomacy through loan exhibitions to British museums http://hdl.handle.net/2381/33072 Title: Imaging China: China's cultural diplomacy through loan exhibitions to British museums Authors: Kong, Da Abstract: China's worldwide cultural promotion has attracted considerable attention in the past decade. Art exhibitions sent out by the Chinese government, as an important part of such initiatives, have been ever more visible in Western museums. How and why the Chinese government uses such exhibitions, however, has rarely been explored. This study examines how such exhibitions have contributed to China's cultural diplomacy, through shaping the image of China in the British media. It demonstrates how China's loan exhibitions contribute to an advanced and civilised, democratic and humanist (with Chinese characteristics), innovative and creative, multi-ethnic and multi-cultural, open, collaborative and peaceful image of China, and how such image is consistent with China's cultural diplomacy in the new century. This study examines the factors which have an impact on the media interpretation of such exhibitions, namely the image of China in the media. It explores the involvement of the Chinese government and the influence of museum professionals on both sides (China and the UK) in producing and delivering these exhibitions, and the relationships between them. It demonstrates that the Chinese government plays a vital role in delivering loan exhibitions, but the role is more bureaucratic and facilitating, rather than didactic or propagandistic. The Chinese government is aware of the value of loan exhibitions for cultural diplomacy, but still allows the museums involved enough freedom in shaping the exhibitions. This study also considers the operation of China's current system of managing loan exhibitions, and their implications for China's cultural diplomacy and Chinese museums. It concludes that the Chinese government should reform the current system to encourage Chinese museums on all levels to actively engage in international collaboration, without intervening in their professional independence. 2015-09-21T13:07:02Z Safety Requirement Patterns for High Consequence Arming Systems http://hdl.handle.net/2381/33071 Title: Safety Requirement Patterns for High Consequence Arming Systems Authors: Slipper, Daniel James Abstract: This thesis details research investigating issues with the way in which safety requirements (often termed assertions) are written for the specific application of high consequence arming systems. Existing methods for deriving such requirements focus on the approach through which these systems are designed. Currently this is based upon three main concepts: isolation, incompatibility and inoperability. These are often referred to as the 3I's, and are used in combination with a fourth I of independence. The issue motivating this research is that there is no rigour in the manner in which these are written and no methods exist to ensure completeness of the resultant requirements set. A systems engineering approach has been adopted to perform this research and considers the needs of stakeholders involved in specification of arming system safety requirements, from these requirements of the project are derived. A solution has been presented in the form of a set of 8 templates which allow repeatable specification of assertions, along with a set of 12 patterns which cover realistic and commonly used relationships between these templates. The template assertions are based upon a state machine format and adopt a novel view of the 3I's where attenuation, incompatibility, state changes and race are used to specify lower level and more detailed requirements than the existing methods. Application of the new approach to real industry projects showed that it identified assertions which were missed using the current state of the art methods. Through use of modelling it has also been demonstrated that the new approach produces a complete set of assertions which, when implemented correctly, provide protection against detonation in a given environment. This approach is intended for use alongside existing methods to produce a set of requirements which meet all regulatory needs, inclusive of independence, something which this approach does not consider. 2015-09-21T12:58:07Z The style of Quaker consumption in British Colonial New Jersey: the link between religious beliefs and values and the archaeological record of the society of friends http://hdl.handle.net/2381/33070 Title: The style of Quaker consumption in British Colonial New Jersey: the link between religious beliefs and values and the archaeological record of the society of friends Authors: Young, Michael Lawrence Abstract: This research focuses on the role of beliefs and values at domestic Quaker sites in British Colonial North America and their transformations through time. Evidence is drawn from building techniques, ceramic and glass tablewares, foodways as manifest through storage/preparation vessels and faunal remains, alcohol and tobacco-related objects, and materials related to dress and personal adornment. The aim of this research is to make substantial contributions to the study of Quakers, to the study of the influence of beliefs and values in colonial situations and past cultural traditions in general, and to the study of the rise and spread of eighteenth-century consumerism associated with the Industrial Revolution. Beliefs and values possess material manifestations. To link the material archaeological evidence to cultural ideals, this proposed research focuses on behavior which may be documented in the archaeological record. The full potential of the archaeological contribution to issues surrounding the varying degree of adherence to Quaker beliefs and values may be realized through consideration of all available types of material culture. An analytical focus on the style of consumption and technology is considered essential for the study of tenets, beliefs, and values in the archaeological record. The revival of archaeological theories of style is advocated as the primary means archaeologists have available to study the manifestation of beliefs, values, and the underlying ethos through variation in material culture. The revival of an archaeological focus on style enables a more full realization of the goals of social archaeology and the consideration of the significance of a research project at the higher scales of relevance: the scale of issues of importance in history and the social sciences in general, and the scale of the contribution research may render towards developing solutions to contemporary social problems. 2015-09-21T12:45:58Z The impact of sedentary time and breaks in sedentary time on markers of cardio-metabolic health http://hdl.handle.net/2381/33069 Title: The impact of sedentary time and breaks in sedentary time on markers of cardio-metabolic health Authors: Henson, Joseph John Abstract: Background: Sedentary behaviour has emerged as a distinctive health behaviour paradigm, showing associations with markers of cardio-metabolic health independent of other lifestyle behaviours, such as physical activity. However, most investigations have been conducted in the general population without reference to specific risk factors and experimental research in humans is lacking. Aims: 1. Undertake narrative reviews investigating the effect of sedentary behaviour upon markers of cardio-metabolic health 2. Conduct a series of observational studies investigating the independent effects of sedentary behaviour on traditional and non-traditional markers of cardio- metabolic health. 3. Design and conduct an acute experimental study to establish whether reducing sitting time through regular bouts of non-sedentary activity improves cardio- metabolic health in women at high risk of T2DM. Key Findings: 1. Experimental studies demonstrate that regularly breaking sedentary behaviour with short bouts of walking imparts acute metabolic advantages. 2. Sedentary time was shown to have stronger associations with 2-hour glucose, triglycerides, HDL-cholesterol compared to moderate-to-vigorous physical activity (MVPA). 3. Sedentary time was associated with interleukin 6 (IL-6), heart, liver and visceral fat, independent of measured confounders, including glycaemia, adiposity and MVPA. 4. Compared to a prolonged bout of sitting, both standing and walking significantly reduced the glucose and insulin incremental area under the curve (iAUC) in women at high risk of T2DM. Conclusions: This thesis synthesizes the current evidence examining the relationship between sedentary behaviour and various health outcomes (Chapters Two and Three). Chapters Four, Five and Six investigate the independent effects of sedentary behaviour on markers of cardio-metabolic health through a series of observational studies. Chapter Seven examines the effectiveness of an experimental study and Chapter Eight discusses the implications of these findings whilst identifying areas for future research. 2015-09-21T12:37:32Z The role of endocannabinoids and their receptors on the regulation of bladder function and detrusor overactivity http://hdl.handle.net/2381/33068 Title: The role of endocannabinoids and their receptors on the regulation of bladder function and detrusor overactivity Authors: Bakali, Evangelia Abstract: The endocannabinoid system (ECS) has been identified in the urinary bladder of humans and rats and is purported to play a modulatory role in detrusor overactivity (DO). Clinical studies demonstrated that cannabis improves urgency in patients with neurogenic DO. However, how endocannabinoids are regulated in vivo as well as the pathophysiological relevance of deregulation of the system in the aetiopathogenesis of DO remain unexplored. This thesis explores the clinical relevance of the ECS in the aetiopathogenesis of DO, by evaluating the effects of cannabinoid agonists on bladder contractions in vitro and in vivo. Cannabinoid receptor (CBR) expression was localised in human and rat bladders. In vitro, ACEA (CB1 agonist) had both pre- and postsynaptic effects on bladder contraction, while GP1a (CB2 agonist) only had postsynaptic effect. CB1 receptor was co-localised with ChAT (choline acetyltransferase enzyme) in human detrusor but not in the urothelium, while CB2 co-localised with ChAT in both urothelium and detrusor. qRT-PCR showed that CB1 receptor was significantly upregulated by 2.8-fold in the urothelium of DO patients and downregulated by 3.2-fold in the detrusor of DO patients compared to normal. Rat cystometry experiments demonstrated CP55,940 (CBR non-selective agonist) significantly increased micturition interval (MI) and bladder capacity (BC) by 52±5.5% and induced a 25 ± 2.9% decrease in maximal pressure (MP). Addition of CP55,940 to rats with induced bladder irritation, showed an increase in MI by 78% ± 16.7% and a 22% ± 5.8% reduction in MP. In conclusion, cannabinoid receptors are involved in normal micturition at both peripheral and CNS sites, data supported by in vitro studies where CB1 reduced neuronal activity and where both cannabinoid receptors modulated bladder contractility. CB1 receptors expressed in afferent fibre endings in the urothelium could influence bladder function. CB1 receptor agonists may be useful for future treatment of DO as there is altered CB1 receptor expression in these bladders. 2015-09-21T12:31:16Z The epidemiology of abdominal aortic aneurysm and natural history of type II endoleak after endovascular aneurysm repair http://hdl.handle.net/2381/33067 Title: The epidemiology of abdominal aortic aneurysm and natural history of type II endoleak after endovascular aneurysm repair Authors: Sidloff, David Adam Abstract: Abdominal aortic aneurysm is an important cause of death globally, however, its impact is less today than two decades ago due to a decline in AAA mortality. Within the same timeframe changes have occurred to the way that AAA may be treated, for example an increasing use of endovascular surgical techniques. Type II endoleak is one of the most common complication of endovascular aneurysm repair. The sequela of having a type II endoleak is however unknown. My objectives within this thesis were to analyse causes of the decline in aneurysm mortality being seen in many developed countries using data derived from the World Health Organisation and investigate short/medium term outcomes of patients with type II endoleak at a single centre in the United Kingdom. Through these studies I have demonstrated a robust association between trends in established cardiovascular risk factors and mortality from AAA suggesting that a reduction in the global burden of high cholesterol (P=0.0082), hypertension (P=0.028) and smoking (P=0.017) have led to a drop in AAA mortality. Aneurysm rupture in patients with an isolated type II endoleak appears to be rare occurring in less than 1% of all literature reported type II endoleaks and no ruptures were recorded in patients with type II endoleak followed up prospectively. Patients with isolated type II endoleak demonstrate equivalent aneurysm related mortality to those without, however, there is a strong independent association between type II endoleak and 5mm of aneurysm sac expansion (P=0.0001). A conservative strategy to the treatment of type II endoleak appears to be safe and given time isolated type II endoleak appear to have a good chance of spontaneously resolving without the need for invasive intervention. For those patients with type II endoleak and 10mm of aneurysm sac expansion, further research is needed to investigate the risk versus benefit of intervention. 2015-09-21T12:22:12Z The regulation and role of MS1 in the cardiac stress response http://hdl.handle.net/2381/33022 Title: The regulation and role of MS1 in the cardiac stress response Authors: Fothergill, Daniel Philip Abstract: Ischaemia reperfusion injury results in metabolic disruption in cardiac cells, potentially leading to cell death and ultimately heart failure. The regulation of the cellular response to ischaemia reperfusion is not fully understood. Previously, the muscle-enriched protein MS1 was shown to be upregulated immediately after physiological and pathological muscle stimulation, possibly acting in the early phase of the stress response. The aims of this work were two-fold. Firstly, to identify transcription factors binding the UP2 site, an evolutionarily conserved putative regulatory region upstream of the MS1 transcriptional start site. In silico analyses were conducted to identify candidate transcription factors, before in vitro assays using H9c2 cardiomyoblasts were used to confirm binding of the identified factors. It was demonstrated that the Ets transcription factors Elf1 and Fli1 can bind the site in vitro, and that Fli1, in concert with GATA2, can modulate MS1 and UP2 expression. Secondly, it was shown that MS1 mRNA and protein are upregulated in response to simulated ischaemia reperfusion in vitro in a similar time-course to its upregulation in pathologically stressed rodent hearts and physiologically stressed human skeletal muscle. In addition, Elf1 knockdown ameliorated this response. It was also demonstrated that MS1 knockdown sensitised cells to oxidative stress. Overall, the findings suggest that MS1 is up-regulated in response to a simulated ischaemia reperfusion protocol in H9c2 cells, and this contributes to the protection of cells against oxidative stress. This response may be facilitated in part by the action of Ets proteins acting at the UP2 site. This thesis provides novel evidence for the involvement of MS1 in cardiomyocyte responses to reperfusion injury, possibly via UP2, and in the cellular protection against oxidant-induced cell death. 2015-09-03T15:00:09Z Physical and Chemical Investigations of Starch Based Bio-Plastics http://hdl.handle.net/2381/33021 Title: Physical and Chemical Investigations of Starch Based Bio-Plastics Authors: Abolibda, Tariq Ziyad Y. Abstract: Starch is one of the most common and easily obtained natural polymers, making it attractive as a potential bio-based alternative to synthetic polymers. The plasticisation of starch is complex due to the extensive hydrogen bonding between chains. This study shows that a simple quaternary ammonium salt combined with hydrogen bond donor (HBD) forms effective modifiers that produce flexible plastics with good mechanical properties that are comparable to some polyolefin plastics. Starch-based plastics can be formed by the same processes as current commercial plastics, giving similar mechanical strength to some polyolefin plastics. The processing conditions are shown to significantly affect the structure of the polymer which has a concomitant effect upon the mechanical and physical properties of the resulting plastic. Using a glycerol based modifier results in a totally sustainable and biodegradable material which can be formed by extrusion, pressing, vacuum forming and injection moulding. Most significantly, it is shown that these plastics are environmentally compatible, recyclable, bio-degradable and compostable. This study has demonstrated the optimisation of the parameters for a range of techniques that are currently used in processing this type of plastic. These include: temperature profiling for both compression moulding and extrusion, residence time in the extruder, drying time and pressing time. Glycerol/choline chloride is the plasticiser that was found to give optimal properties and has been used for most of this study. The optimum ratio is shown to be 1:3 by weight plasticiser: starch. In addition, five different systems of fillers have been added to the starch based plastics to study their effect on tensile strength and strain, glass transition temperature, viscoelasticity, crystallinity, morphology and rheology. The chemical changes have also been investigated after the addition of the five fillers which are eggshell, wood-flour, silk, zein and lignin. Furthermore, the fillers have an effect on stabilising water content in thermoplastic starch. Water uptake and water loss have been examined using thermogravimetric analysis, water absorption isotherms, water absorption capacity and contact angle. Finally, some applications have been presented for protecting these plastics from surrounding moisture. 2015-09-03T14:53:37Z Capital structure in Europe: determinants, market timing and speed of adjustment http://hdl.handle.net/2381/33020 Title: Capital structure in Europe: determinants, market timing and speed of adjustment Authors: Zhu, Ting Ting Abstract: In broad terms, the aim of this thesis is to investigate the determinants of capital structure in European-listed firms. More specifically, it examines the existence of market timing effects in European firms and the speed of adjustment towards optimal capital structure as well as its determinants. Over the last two decades, Europe has undergone an intriguing experience involving changes in the political geography, financial liberalization, financial integration, a financial crisis and, most recently, financial reform. These exogenous shocks have taken their toll on European capital markets and banking sectors. In particular, the recent financial crisis has unveiled a number of inefficiencies in the incomplete financial integration process in terms of weak governance and ineffective regulations. The crisis period witnessed an increase in the following: the probability of bankruptcy; the number of banks and firms failing; illiquidity; and a significant loss in firms' values. This in turn affected the flow of funds into firms either from bank lending channels or from capital markets. Indeed, such financial turmoil calls for further investigation into the determinants of firms' capital structure in the European markets. This thesis contributes to the literature in two ways. First, this is the first study that empirically tests the market timing theory in 15 European countries. Second, it adds to the scant literature on comparative studies that examine the target capital speed of adjustment and its determinants. The thesis employs various econometric models to analyse the unbalanced panel data collected from 15 European countries. The generalized method of moments (GMM) estimator (among other panel data techniques) is deemed appropriate to estimate the models. It is designed to accommodate the unbalanced panels, multiple endogeneity and the autoregressive properties in the dependent variable. The new evidence provided by the findings of this study will be of great interest to the literature and policy-makers. The results confirm the effect of market valuation. However, it is negative in Europe, rather than positive as theory suggests. The results provide evidence that partially supports both pecking order and trade-off theories. For European firms, the annual speed of adjustment towards target capital is, on average, one quarter for book leverage and one half for market leverage. Firms in the Netherlands and Finland are the fastest to adjust their capital while firms in France and Spain are the slowest. The driving forces of the adjustment speed reveal that firms adjust more rapidly in wealthier and healthier environments such as those which involve a stable economy, a concentrated banking system and a promising future. Description: The file associated with this record is under embargo for 12 months 2015-09-03T14:42:17Z Mechanism of solidification cracking during welding of high strength steels for subsea linepipe http://hdl.handle.net/2381/33019 Title: Mechanism of solidification cracking during welding of high strength steels for subsea linepipe Authors: Aucott, Lee Alan Abstract: Weld solidification cracking is an important issue in fusion welding. If undetected, the cracking defects can act as stress concentration sites which lead to premature failure via fatigue, as well as offer favourable sites for hydrogen assisted cracking and stress corrosion cracking. For welded steel products such as deep sea oil and gas transportation pipes, such defects heighten the risk of catastrophic in-service failures. Such failures can lead to devastating environmental, economic, and social damage. In this thesis, a comprehensive review of literature associated with steel linepipe and solidification cracking defects is first presented. Fluid flow prior to solidification is then observed and quantified in situ using a novel synchrotron X-ray radiography approach. The flow is dynamic at velocities up to 0.52 m/s and primarily driven via Marangoni flow. The relationship between the microstructure and mechanical properties of the welded linepipe are extensively characterised, with a new equation derived to assess fracture toughness based on the size and distribution of carbonitride precipitates. Weld residual stresses are measured both before and after linepipe expansion in the U-forming, O-forming and expansion process for the first time using a neutron diffraction technique. To further understand the fundamental mechanisms of solidification cracking during welding of high strength steels for subsea linepipe, a novel small-scale Varestraint test rig was developed for use in synchrotron X-ray imaging experiments and a Transvarestriant test rig utilised for industrial scale weldability tests. Solidification cracking during the welding of steel is observed in situ for the first time using a micro-radiography approach and the 3D crack network is rebuilt using a micro-tomography technique. It is proposed that solidification cracks nucleate from sub-surface cavities associated with: i) residual liquid high in solute and impurity concentration (hot cracks), ii) Ti (C,N) precipitated during solidification (that induce ductile microvoids). Solidification cracks then propagate via inter-dendritic hot tearing. 2015-09-03T14:33:57Z Ties that Bind: The role of shared affect in collective action http://hdl.handle.net/2381/33018 Title: Ties that Bind: The role of shared affect in collective action Authors: Allen, Frances Anne Murray Abstract: This thesis focuses on social-affective dynamics in the formation and cohesion of a team working in a complex collaboration crossing government, non-profit, and business sectors. Cross-sector collaborations are increasingly used in solving complex problems, necessitating a better understanding of what keeps actors committed to working together when relational and time commitments become strained. While cognitive reasons and mechanics of team formation are important, equally important are social and emotional reasons individuals find to stay committed to each other and the powerful impact they could have together. Social and affective elements of group cohesion are interdependent with the rational-cognitive, yet they are under-represented in research on complex teams. To explore the mediating process of shared affect in building relational cohesion, micro-ethnographic research was deployed for a 7-month period in following a Collective Impact (CI) initiative to improve early childhood school readiness in a particular US community. This produced a rich cross-sector case study portraying what binds coalition actors to each other to achieve extraordinary commitment to collective action in addressing the community challenge. Extending previous research on person-to-group ties, the findings reveal type and frequency of social exchange are insufficient to understanding the emergence of shared commitment, as prior emotional history among participants and their perceived expectations play a role. The research also indicated that productive exchange may not be possible without first embedding negotiated exchange inside a reciprocal exchange relationship. Finally, the findings were also considered through the lens of several prominent theories on group interaction as well as human intrinsic needs, yielding several opportunities for theoretical intersection and integration. The thesis concludes the Theory of Social Commitments has merit in a real world case study and argues for more qualitative research to round out and deepen the existing body of knowledge on moving from person-to-person to person-to-group ties and the conditions whereby groups may chart their own course to collective action and impact. 2015-09-03T14:24:37Z Bridging the Eastern and Western Mediterranean: The Roman Harbour Sites on the Coast of Cyrenaica, North-Eastern Libya http://hdl.handle.net/2381/33017 Title: Bridging the Eastern and Western Mediterranean: The Roman Harbour Sites on the Coast of Cyrenaica, North-Eastern Libya Authors: Hesein, Mohamed A.H. Abstract: This thesis examines the results of an archaeological survey along a 50 km coastal strip of al-Jabal al-Akhdar (Green Mountain) in Cyrenaica (north-eastern Libya). The survey aimed to assess Cyrenaican ports during the Roman period, and secondary and minor harbours in particular. The conclusions demonstrate that a significant amount of productive and trading activity took place in this area in antiquity. This challenges previous assumptions that only major ports such as Apollonia, Ptolemais and Berenice were involved in trade. This study demonstrates the potential of secondary and small harbours to inform research about the economic role, mechanisms and hierarchy of harbours, in contrast to the prevalent trend among scholars to focus on the study of mega and major-ports. The new evidence has greatly increased our knowledge about productive activity along the coast of Cyrenaica, for example via the identification of 12 new amphora kilns. Initial estimates of the capacity of the vats recorded suggest that these harbours were involved in large-scale manufacturing. A further important strand of research involved an in-depth study of the physical features of the harbours and the construction techniques used in the buildings. An initial typology of these harbours was created to distinguish their roles and hierarchy, and provide a broader framework for their chronology. This analysis suggested that the secondary and minor harbours and other major ports were all well organised and interconnected. Each harbour seems to have played a particular role within the complex trade networks operating out of Cyrenaica. Finally, an investigation of the products imported to Cyrenaican harbours over time uses the ceramic evidence recorded during field survey or published sherds. This allows the discussion of some of the principal components of the import-export trade. A detailed gazetteer of the sites studied is presented in the appendices. Description: The file associated with this record is under embargo for 3 years. 2015-09-03T14:17:07Z A mixed methods investigation into the perceptions of lower secondary school students and teachers in Cyprus on the purposes and approaches of assessment http://hdl.handle.net/2381/33016 Title: A mixed methods investigation into the perceptions of lower secondary school students and teachers in Cyprus on the purposes and approaches of assessment Authors: Solomonidou, Georgia Abstract: The role of assessment in education has been vital, since the earliest establishment of formal education. Though assessment in its early history was used only as a measurement instrument, alternative assessment of student achievement has arrived on the scene the past two decades. It is accepted that assessment can be used for learning also known as Formative Assessment. In this context, many studies have emerged worldwide investigating students' and teachers' perceptions on assessment approaches and purposes as these will affect their practices. The current study uses a Sequential Mixed Methods design to investigate perceptions on the purposes of students' assessment in general and the assessment framework specific for the Modern Greek language subject within the New National Curriculum in Cyprus (NNC). The methods involved two questionnaires; the one administered to Greek language teachers (N=95) followed by 7 individual interviews and the other administered to lower secondary school students (N=599) followed by three group interviews involving 15 students in total. The qualitative data helped explain and build upon initial quantitative results while involving people from the same sample. Results are discussed in light of other research showing that the perceptions of teachers and students are in alignment with the current shift of assessment to be used for enhancing teaching and learning. Both parties tend to agree with the legitimate purposes of assessment. Teachers and students would like to use the elements of Formative Assessment as promoted by the NNC but feel that there is inadequate training, a lack of literature and concrete examples on how to put these elements into practice. 2015-09-03T14:02:32Z Use of Non-mammalian Models to Assess the Virulence of Pseudomonas aeruginosa http://hdl.handle.net/2381/32941 Title: Use of Non-mammalian Models to Assess the Virulence of Pseudomonas aeruginosa Authors: Crosatti, Marialuisa Abstract: Pseudomonas aeruginosa (P. aeruginosa) is the archetypical opportunistic pathogen that accounts for significant numbers of cases of hospital-acquired infections. It adapts to diverse environments in part because it may "modify" its genome through horizontal gene transfer (HGT). Caenorhabditis elegans (C. elegans) and Acanthamoeba spp. (A. castellanii and A. polyphaga) can be employed as in vivo surrogates to investigate the virulence associated with P. aeruginosa clinical isolates and with the presence of genomic islands, genetic elements acquired through HGT. A PA14 based P. aeruginosa pathogenicity island (PAPI)-2 minus mutant exhibited only a minor reduction in virulence as measured by C. elegans survival using the slow-killing assay (SKA) model of virulence but significant attenuation of virulence was found as assessed by the expansion of A. castellanii but not A. polyphaga film on non-nutrient agar. A C. elegans highthroughput assay (HTA) was also established as model of infection and validated against the SKA. The HTA was employed to screen a panel of P. aeruginosa mutants created by deletion of tRNA-associated genomic islands. Few mutants (5 out of 21) showed attenuated virulence toward C. elegans in HTA many of which were confirmed to be less virulent toward the nematode using SKA. Screening of clinical isolates linked the strains isolated from blood culture of a patient with lower survival of C. elegans in HTA compared with strains isolated from sputum. Moreover, type III secretion system effector (T3SS) exoU-positive strains and strains developing pigments during growth were more virulent toward C. elegans in HTA than T3SS effector exoS-positive strains and pigment-less strains, respectively. Since pigment development was also linked to exoU and this gene has been associated with genomic islands integrated at tRNALys10, it was inferred that these genomic islands may bear functions affecting C. elegans survival possibly enhancing iron scavenging. 2015-08-12T15:36:28Z Historical and contemporary archaeologies of social housing: changing experiences of the modern and new, 1870 to present http://hdl.handle.net/2381/32940 Title: Historical and contemporary archaeologies of social housing: changing experiences of the modern and new, 1870 to present Authors: Dwyer, Emma Abstract: This thesis has used building recording techniques, documentary research and oral history testimonies to explore how concepts of the modern and new between the 1870s and 1930s shaped the urban built environment, through the study of a particular kind of infrastructure that was developed to meet the needs of expanding cities at this time – social (or municipal) housing – and how social housing was perceived and experienced as a new kind of built environment, by planners, architects, local government and residents. This thesis also addressed how the concepts and priorities of the Victorian and Edwardian periods, and the decisions made by those in authority regarding the form of social housing, continue to shape the urban built environment and impact on the lived experience of social housing today. In order to address this, two research questions were devised: • How can changing attitudes and responses to the nature of modern life between the late nineteenth and early twentieth centuries be seen in the built environment, specifically in the form and use of social housing? • Can contradictions between these earlier notions of the modern and new, and our own be seen in the responses of official authority and residents to the built environment? The research questions were applied to three case study areas, three housing estates constructed between 1910 and 1932 in Birmingham, London and Liverpool. During the course of answering these research questions, three further themes have arisen, which have broader relevance beyond this thesis: • How to interpret buildings that have a life extending beyond their original purpose. • The practice of contemporary archaeology as it relates to the built environment • How new kinds of environments are created and experienced, and how this can be investigated through material evidence. 2015-08-12T15:24:54Z Development of a hybrid portable medical gamma camera http://hdl.handle.net/2381/32939 Title: Development of a hybrid portable medical gamma camera Authors: Bugby, Sarah Louise Abstract: A novel small field of view medical gamma camera - the Compact Gamma Camera (CGC) - has been developed at the University of Leicester to provide portable, high-resolution gamma imaging for applications in nuclear medical imaging. The suitability of this camera for medical imaging is investigated through Monte Carlo simulation, phantom studies and preliminary clinical testing. Quality assurance protocols are adapted for use with small field of view gamma cameras. These protocols are then used to provide a full characterisation of the CGC. The CGC is found to compare favourably to other small field of view systems in development. Phantom studies are described which show that the CGC is well suited to intraoperative imaging, particularly for use in sentinel lymph node biopsy. A Monte Carlo model is described that is designed to simulate the response of a pinholecollimated, scintillator-based gamma camera. The model is shown to accurately model sensitivity and spatial resolution. Previously derived analytical models are shown to be unsuitable for modelling finite source profiles and a new analytical model is described which addresses this shortcoming. This model is used to define appropriate test source sizes for the characterisation of small field of view systems. A modified version of the CGC - the Hybrid Compact Gamma Camera (HCGC) - is described which includes an optical imager in a coaligned configuration. The HCGC allows for functional and anatomical images to be obtained simultaneously. The use of hybrid optical-gamma imaging is novel in small field of view cameras and offers new possibilities for assisting surgeons in localising the site of uptake in procedures such as sentinel node detection. 2015-08-12T15:15:55Z Changing work and employment institutions in Mauritius: Challenges for workers, companies and education and training institutions http://hdl.handle.net/2381/32938 Title: Changing work and employment institutions in Mauritius: Challenges for workers, companies and education and training institutions Authors: Emilien, Stephanie Blandine Abstract: This thesis critically explores how changing work and employment institutions have brought about challenges for workers, companies and Education and Training institutions in Mauritius. The study uses a historical institutionalist approach as well as additional concepts to examine how Work and Employment as well as Education and Training institutions of Mauritius, have adjusted to contemporary economic conditions. Recently, Mauritius, a former French and British colony, has diversified its economy and launched its Business Process Outsourcing (BPO) sector. The sector has developed in parallel with the government's endeavour to turn Mauritius into a knowledge economy over time. In order to facilitate the setting up of numerous multinational companies, the country has adopted more flexible employment legislation. As a result, companies have been able to take advantage of the island-nation's cheap, multi-lingual and youthful labour market. The thesis identifies challenges that have been triggered by the requirement for new skill capacities, and further challenges in the form of risks experienced by young Mauritian workers in their employment relationships. Through a qualitative empirical approach, 75 semi-structured interviews were undertaken with workers, managers, educationists and experts in Mauritius. The study argues that current and forthcoming Education and Training (E&T) Policies face several tensions that the Mauritian government did not anticipate and cannot adequately deal with. Findings show disparities between employers' expectations of workers' level of employability and skill capacities on the one hand and actual skill capacities on the other. Tensions also lie between the government and private employers in regard to who is to provide which form of training. Further contradictions are found in the government's one-sided efforts towards building a 'high-skill' workforce while new pillars of the economy, here illustrated by the BPO sector, can be comparatively low-skill. Considering the absence of union organisation and the generally low level of agency among workers, these tensions can have damaging impact upon young Mauritian workers at work and beyond. In conclusion, the study highlights the importance of considering context-specificity in the formulation of E& T policies. It suggests that there is much scope for institutional change in which education systems and policies can be more carefully designed to address new economic and social needs in Mauritius. 2015-08-12T15:07:07Z The mechanistic basis of Nek7 activation through Nek9 binding and induced dimerization http://hdl.handle.net/2381/32937 Title: The mechanistic basis of Nek7 activation through Nek9 binding and induced dimerization Authors: Haq, Tamanna Abstract: Mitosis is a tightly coordinated process that is regulated by many proteins to ensure the correct segregation of chromosomes and the production of two genetically identical daughter cells. Incorrect mitotic spindle assembly and the incorrect segregation of chromosomes often results in aneuploidy, which gives rise to very severe consequences such as tumorigenesis and cancer. The mitotic kinases, Nek6, Nek7 and Nek9 play a pivotal role within mitotic spindle assembly and their dysregulation has been associated with several cancers and solid tumour formation. Previous work has demonstrated that Nek7 exists in an autoinhibitory conformation as a result of the aromatic side chain of tyrosine-97 protruding into the active site and forming a hydrogen-bond with leucine-180 of the aspartate-leucine-glycine (DLG) motif (which is aspartate-phenylalanine-glycine (DFG) motif in most kinases). Mutation of tyrosine-97 to an alanine (Y97A) or phenylalanine (Y97F) residue results in a hyperactive kinase. The addition of the non-catalytic C- terminal domain of Nek9 relieves the autoinhibition of wild-type Nek7, but the hyperactive Nek7 mutant overrides the effect of the Nek9 C-terminal domain (CTD). This study focuses on mapping the site of the Nek7-Nek9 interaction and key residues involved through the use of GST co-precipitation assays and confirming the binding site using X-ray crystallography. The minimal binding region of Nek9810-828 binds at a novel allosteric site on the C-lobe of Nek7Y97F, but it alone is not sufficient to activate Nek7. Nek7Y97F crystallised as a back-to-back dimer, forming interactions mainly via its N‐lobes. The self-association of the Nek9-CTD via its coiled-coil domain is necessary for the activation of Nek7. Here we propose a novel mechanism for Nek7 activation where Nek9 oligomerises via its coiled-coil domain and binds to oligomers of Nek7, which can subsequently form back-to-back dimers and autoactivate to enhance their kinase activity. 2015-08-12T14:59:45Z Ion Transfer Dynamics of Polyaniline and Its Derivatives in Energy Storage and Water Purification http://hdl.handle.net/2381/32905 Title: Ion Transfer Dynamics of Polyaniline and Its Derivatives in Energy Storage and Water Purification Authors: Yavuz, Abdulcabbar Abstract: This thesis concerns the electrochemistry of electroactive conducting polymer films in novel ionic liquid media of relevance to energy storage devices and in aqueous media for water purification. The processes taking place at the interfaces of the electrolytes and modified electrodes are important for improving the performance of electrochemical devices. Understanding physical and chemical behaviours of both components and their interfacial dynamic are the aims of this thesis. Polyaniline (PANI), its derivatives and copolymer modified electrodes were deposited with a combination of electrochemical (cyclic voltammetry) and acoustic wave (EQCM) measurement. The optical, electrochemical and morphological behaviours of the resulting films were characterised. Quartz crystal impedance analysis was for the first time used to identify deviations in liquid behaviour from Newtonian, depending on temperature. Ion exchange dynamics of PANI modified electrode in deep eutectic solvents (DES) was used to shed light on supercapacitor applications. Various aspects of the behaviour of PANI films exposed to DES media in the potential range corresponding to p-doping were identified. The rate limiting process, different switching processes and performance of resulting films depend not only on the film coverage but also on the growth conditions. PANI films cycled in non-aqueous media for supercapacitor applications were also used in non-acidic medium for the Electrically Switched Ion Exchange (ESIX) process. The concept is that PANI oxidation is accompanied by fluoride uptake in neutral solution and then eliminates fluoride into a different aqueous acidic waste stream. The mechanism and fundamentals of this concept were monitored by using the EQCM. Description: The file associated with this record is under embargo for 12 months at the request of the author. 2015-08-05T15:19:29Z Bio-spheres of Risk-Aversion and Equitable Health. An Ethnography of Neoliberal Area-Based Public Health Policy Intervention and Physical Activity in a Deprived English Neighbourhood http://hdl.handle.net/2381/32904 Title: Bio-spheres of Risk-Aversion and Equitable Health. An Ethnography of Neoliberal Area-Based Public Health Policy Intervention and Physical Activity in a Deprived English Neighbourhood Authors: Williams, Oliver Stephen Abstract: The aim of this thesis is to explore the relationships between health, place and inequality. The research focuses on area-based public health policy in a deprived neighbourhood - 'Kingsland' - in central England. Kingsland attracted a number of area-based initiatives (ABIs) with the overarching aim of reducing national inequality. Between 2000-2010, significant resources were invested in local projects to promote 'healthy' living: most notably through physical activity (PA). Kingsland became a relatively novel place: a deprived area with numerous PA facilities and services. A central research concern is how far these services, particularly a new local leisure centre, impact the lives of people of low-SES. Localities transformed in ways designed to promote 'healthy' living are conceptualised as 'bio-spheres of risk-aversion' and assessed for their potential to address health inequalities. This research took place two years after the ABIs were implemented. Data primarily come from sixteen months of ethnographic observation, but also includes interviews, a survey, and document analysis. Relationships between health, place and inequality are considered within the wider context of neoliberal dominance. The example of the global obesity 'epidemic' illustrates the ways in which neoliberal ideology promotes individual responsibility. The 'oppressive' and 'emancipatory' potentials of neoliberal health policy are explored in relation to the 'choices' and embodied experiences of people of low-SES. This research demonstrates that neoliberal policies not only have harmful individual consequences, they also exacerbate structural inequalities. Specifically, analysis indicates the potential for ABIs to exacerbate health inequalities. Findings reveal some direct, detrimental impacts on people of low-SES and highlight the importance of equitable health provision. This thesis makes an original contribution by revealing the paradoxical effects that health policy can have on relationships between health, place and inequality. It offers a set of novel theoretical concepts to better understand this paradox and to guard against it. 2015-08-05T15:13:29Z Assessment of physiological status and spatial distribution of emergent macrophytes based on imaging spectroscopy http://hdl.handle.net/2381/32903 Title: Assessment of physiological status and spatial distribution of emergent macrophytes based on imaging spectroscopy Authors: Stratoulias, Dimitris Abstract: Wetlands are ecosystems encountered at the land-water ecotone and hence inheriting rich complexity and biodiversity. Emergent macrophytes are a prime example of this variability manifested by the co-occurrence of vegetation associations at a very fine spatial level. From 1960s onwards an abrupt deterioration of reed beds in Europe has been systematically observed and denoted as the 'reed die-back'. Since then, earth observation has been utilized mainly to map the extent of reed beds based on multispectral information. Hyperspectral remote sensing has frequently been employed in vegetation related studies, however the spectral information content of macrophytes has not been widely investigated. This study focuses on assessing the potential of imaging spectroscopy for assessing the ecophysiology of lake shore vegetation at leaf level and mapping macrophytes species associations from airborne imagery. Concurrently acquired spectroscopic, chlorophyll fluorescence and chlorophyll content information from field samples around Lake Balaton, Hungary are employed to identify spectral regions and propose narrowband indices which can aid the identification of reed ecophysiological status based solely on vegetation spectral characteristics. Macrophyte species as well as Phragmites in different phenological states have concretely separate spectral responses, however stable and die-back reed are not crucially different. Bathymetry regulates consistently the spectral response of Phragmites. Narrow band ratio 493/478 (0.65***) correlates with the ETR, the latter being an indication of the photosynthetic activity of the plant, and hence the vegetation physiological status. Most indices correlating with fluorometric parameters are located in the optical domain. Based on R2 graphs, the ratios 699/527 and 612/516 can be used to estimate Y(II) from AISA hyperspectral data. Estimation of the photophysiological parameters of a reed bed is possible based solely on airborne hyperspectral imagery. Simultaneously acquired airborne AISA Eagle, Hawk and discrete return LiDAR data are combined in order to stress out the potential of each dataset in classifying the reed bed in terms of species associations. An application of SVM on noise-reduced Eagle data, at the chlorophyll and near infrared absorption spectral regions, provides the most concrete results in terms of overall accuracy (89%). SVM outperforms ML and infrared sensors as well as LiDAR data do not improve the categorization of macrophyte classes. While airborne data inherit a superior spectral and spatial resolution, they are difficult to acquire in an operational context. Upcoming satellites will provide imagery with progressively higher spatial and spectral capabilities. A simulation of Sentinel-2 image over a reed bed in a nature protected area indicates the potential of satellite imagery in mapping macrophytes. Main classes can be distinguished, despite the fact that inter-class separability is becoming vague. Given the very large swath of Sentinel-2 (290km) an operational categorization of main macrophytes is foreseen achievable. 2015-08-05T15:04:08Z Firm size inequality: industry dynamics, entrepreneurship and welfare http://hdl.handle.net/2381/32902 Title: Firm size inequality: industry dynamics, entrepreneurship and welfare Authors: Puntaier, Elmar Abstract: This thesis analyses the dynamics and determinants of the size distribution of firms and examines its implications on welfare. It draws on Schumacher's proposition of a 'balanced' size distribution of firms as a precondition for sustainable economic development, which conflicts with models predicting an increase in firm size inequality in the long run. For the said dynamism to be understood, the historical development from the First Industrial Revolution is reproduced and emerging patterns set in relation to the evolutionary approach to economic development. This leads to the central argument of this thesis, which is the need for a fair share of medium-sized firms in order to maximise innovative capacity, economic resilience, net job creation and sustainability. To identify the forces driving firm size inequality and the extent to which rebalancing is possible, this thesis consolidates the streams Gibrat's Law initiated. The industry-level analysis of the UK, Italy and Germany from 2001 to 2010 demonstrates that the size distribution of firms converges to a lognormal distribution. For technology-rich firms, firm size inequality is inversely U-shaped and the systemic erosion of diversity reduces the options to rebalance. In service industries, industry dynamics are more intense and cause a faster increase in firm size inequality. The resulting co-existence of small and large firms reduces spill-over effects and the ability to recover from macro-economic shocks, but these, paradoxically, increase firm size inequality. To delay the process of increasing firm size inequality, small and medium-sized firms need to engage with export activities and accumulate intangible assets. As the owner-managed firm commercialises on uncertainty and the large firm escapes from it, preserving the 'middle' is rewarded with a higher degree of innovative capacity and contributes to sustainable growth. There are also windows of opportunity where rebalancing is possible and from these openings new industries emerge. Description: This file associated with this record is under embargo for 12 months at the request of the author. 2015-08-05T14:58:59Z To What Extent do Informal Learning and Technology Transfer Impact Absorptive Capacity? http://hdl.handle.net/2381/32901 Title: To What Extent do Informal Learning and Technology Transfer Impact Absorptive Capacity? Authors: Nakale, Metusalem Abstract: This thesis aimed to investigate the extent to which informal learning and technology transfer impact absorptive capacity and to uncover how individual social agents contribute to the development of absorptive capacity. Research on absorptive capacity has hitherto mainly focused on the use of proxies such as R&D intensity and the number of PhD holders in organizations to measure absorptive capacity. This preoccupation with proxies has retarded progress with respect to our understanding of how absorptive capacity is developed. The literature review revealed that most previous studies employed the quantitative paradigm and failed to capture the contextual dimensions of absorptive capacity. Most studies focused mainly on organizational level aspects thereby neglecting the individual antecedents of absorptive capacity. In order to reveal aspects of absorptive capacity development that quantitative studies are unable reveal, this study employed a qualitative paradigm, based on the constructionist philosophy. The data were generated through the use of semi-structured interviews, supplemented by field notes. The data analysis drew on the grounded theory approach. The evidence generated by this study shows that informal learning and knowledge/ technology transfer impact the ability to integrate and use external knowledge through individual agency. The findings also show that individual employees rely on their cognitive resources to acquire knowledge. Further, the results suggest that working with others, interacting with them, helps with knowledge transfer and institutionalization. The main implications of this study are that managers need to facilitate the creation of more learning opportunities in the workplace. Such learning has the potential to contribute significantly to the aspiration of creating a knowledge economy, especially in the context of Namibia. Also, organizations need to forge more links with industrial forerunners in order to learn from them and build up their own technological capabilities. 2015-08-05T14:49:35Z Iron age and Roman-era vehicle terrets from western and central Britain: an interpretive study http://hdl.handle.net/2381/32900 Title: Iron age and Roman-era vehicle terrets from western and central Britain: an interpretive study Authors: Lewis, Anna Sian Grodecka Abstract: This thesis presents an interpretive study into the development, distribution, use and deposition of Iron Age and Roman-era terrets, or rein-guides, from western and central Britain. It is the first in-depth study of terrets as an artefact class and, unlike previous catalogues of Iron Age or "Celtic" metalwork, includes terrets of Continental or Roman stylistic origin as well as the "D-shaped" British series. The accompanying database records 596 terrets from within the study area. The "D-shaped" series first emerged around the third century BC, and appears to have taken a stylistic leap in the early first century AD, when terret design became increasingly varied and frequently involved the inclusion of colourful enamels. From the mid-first century AD, Continental-influenced forms became widespread in Britain. The D-shaped series continued to evolve, whilst adhering to basic conventions and constraints, until chariotry fell into decline around the end of the first century AD. The thesis re-assesses dating evidence for the development of the artefact class, and proposes a new typology organised into three main typo-chronological groups. The inter-relation of D-shaped and Continental varieties is investigated, the distribution across the study area of different forms compared, and depositional contexts reviewed. The social significances of D-shaped terrets in particular are also considered, as communicated both through their artistic development and through the behaviours evident in their deposition. Moving from the Late Iron Age into the Early Roman era, the thesis makes use of object theory and post-colonial theory to interpret the changing social roles of terrets in the context of Roman invasion and occupation. Description: 2 Access Databases included as Appendices 2015-08-05T14:40:22Z Submillimetre observations of dusty, luminous, high-redshift galaxies http://hdl.handle.net/2381/32899 Title: Submillimetre observations of dusty, luminous, high-redshift galaxies Authors: Jones, Suzy Frederica Abstract: This thesis presents submillimetre (submm) observations using the James Clerk Maxwell Telescope (JCMT) Submillimetre Common-User Bolometer Array 2 (SCUBA-2) of dusty, luminous, high-redshift galaxies. Submm wavelengths are important because the coldest dust properties can be observed, which can help with the calculation of total infrared (IR) luminosities. Three samples of galaxies are investigated in Chapters 3, 4 and 6. The galaxies in Chapter 3 are selected using the Wide-Field Infrared Survey Explorer (WISE) with extremely red mid-IR colours. From previous studies these galaxies are a rare population of dusty, hot (60 - 120K), high-redshift 1 < z < 3, hyper-luminous galaxies and are known as hot dust-obscured galaxies (WISE-selected Hot DOGs). The galaxies in Chapter 4 are selected in a comparable method but are also radio-selected. These galaxies with radio emission are thought to have radio-jet dominated feedback. The galaxies from Chapter 3 and 4 are amongst the most luminous galaxies in the Universe and could be undergoing intense AGN-driven feedback. This feedback could be the result of major mergers between two gas-rich galaxies and are thought to be an important mechanism in galaxy evolution. Chapter 5 compares the two samples of galaxies in Chapters 3 and 4 and also their environments. The environments around high-redshift far-IR and mid-IR luminous galaxies appears to be above average. The overdense environments could yield evidence for the nature of their massive dark matter halos and highlight their bias as compared with the underlying dark matter distribution. The galaxies in Chapter 6 were selected in the millimetre (mm) wavelengths using Planck to have dusty spectral energy distributions (SEDs). Submm observations are used to determine if they are candidates for dusty, luminous, high-redshift galaxies and to obtain more accurate positions. Consequently this will help future searches of dusty, luminous, high-redshift galaxies using successive all-sky Planck data releases. 2015-08-05T14:32:05Z A Calculus of Mobility and Communication for Ubiquitous Computing http://hdl.handle.net/2381/32898 Title: A Calculus of Mobility and Communication for Ubiquitous Computing Authors: Gul, Nosheen Abstract: Ubiquitous computing makes various computing devices available throughout the physical setting. Ubiquitous computing devices are distributed and could be mobile, and interactions among them are concurrent and often depend on the location of the devices. Process calculi are formal models of concurrent and mobile systems. The work in this thesis is inspired by the calculus of Mobile Ambients and other process calculi such as Calculus of Communicating Systems which have proved to be successful in the modelling of mobility, communication and structure of systems. We start by developing operational semantics for the calculus of Mobile Ambients and Push and Pull Ambient Calculus, and prove that the semantics are sound and complete with respect to the corresponding underlying reduction semantics. This thesis proposes a Calculus of Communication and Mobility, denoted by CMCPCA, for the modelling of mobility, communication and context awareness in the setting of ubiquitous computing. CMCPCA is an ambient calculus with the in and out capabilities of Cardelli and Gordon as well the push and pull capabilities of Phillips and Vigliotti. CMCPCA has a new form of global communication similar to that in Milner's CCS. We define a new notion of behavioural equivalence for our calculus in terms of an observation predicate and action transitions. Thus, we define barbed bisimulation and congruence, and capability barbed bisimulation and congruence. We then prove that capability barbed congruence coincides with barbed congruence. We also include in the calculus a new form of context awareness mechanism that allows ambients to query their current location and surrounding. We then propose reduction semantics and operational semantics for the context awareness primitives, and show that the semantics coincide. Several case studies and a variety of small examples show the expressiveness and usefulness of our calculus. 2015-08-05T14:17:23Z STEREO observations of solar wind transients in the inner heliosphere http://hdl.handle.net/2381/32897 Title: STEREO observations of solar wind transients in the inner heliosphere Authors: Conlon, Thomas Michael Abstract: This thesis investigates the implications of relaxing assumptions inherent in techniques that analyse solar wind transients observed by NASA's Solar TErrestrial RElations Observatory (STEREO). In the first research chapter, I relaxed the assumption that the STEREO spacecraft are stationary while observing a transient. For much of the parameter space investigated, this effect was minimal, however in some cases it resulted in differences in derived radial speeds of hundreds of km s-1, leading to large errors. Using real data examples, the difference this effect makes was shown. The second research chapter applies the previous analysis to Corotating Interactions Region (CIR) observations. CIR events were identifed in STEREO HI J-maps, analysed, and their predicted arrival times calculated at each of the STEREO and Advanced Composition Explorer (ACE) spacecraft. A superposed epoch analysis was conducted using the predicted arrival times as the zero epoch time. It was found that when the fixed STEREO spacecraft assumption was relaxed, the CIR related transients that I observed had their estimated propagation speed increase such that they were propagating at (or close to) the slow solar wind speed, a physically realistic change. Changes in the structure of a stream interface over 1-2 days were seen, calling into question some of the underlying assumptions, which assume constant propagation characteristics over longer time-scales. Finally, I consider acceleration of solar wind transients close to the Sun. I use the analysis from previous chapters to perform fits to transient trajectories close to the Sun and infers the size of the acceleration region required to achieve convincing fits at low elongation values. It was found that the behaviour of the transients is consistent with an acceleration region within which the transient accelerates and then adopts a constant propagation speed. The acceleration region does not appear to occur at a fixed radial distance, but rather is different for each event analysed. 2015-08-05T13:55:16Z Neutron reflectometry studies of conducting polymer films http://hdl.handle.net/2381/32896 Title: Neutron reflectometry studies of conducting polymer films Authors: Beebee, Charlotte Anne Stillwell Abstract: Within the field of conducting polymers, it is well understood that the variables in film formation, ranging from the polymerisation and deposition methodologies to the supporting electrolyte in the deposition solution, can produce a wide range of different electrochemical and structural properties for a given polymeric species. For the most part, studies into these effects rely on spectroscopic, electrochemical and surface characterisation techniques. In this work, neutron reflectometry is used to identify the extent of solvent content and spatial distribution within polymer films, providing insight into the internal structure. In conjunction with electrochemical methods, two types of variables are explored: the addition of carbon composites and the electrochemical control function used for polymerisation/deposition. The effect of the incorporation of carbon nanoparticles is explored in the case of composite poly(3,4-ethylenedioxythiophene)-nanodiamond films. These are revealed to be similarly electroactive to pristine poly(3,4-ethylenedioxythiophene) films but present a more ordered internal structure. The effect of the electrodeposition method is investigated by comparing films produced by potentiodynamic, potentiostatic and galvanostatic deposition in the case of two different polymers, polypyrrole and poly(3,4-ethylenedioxythiophene). The results show that the polymerisation efficiency for a given growth protocol differs depending on the polymer species, as do the structural variations, such as porosity or structural stability following charge/discharge processes. 2015-08-05T13:47:03Z Resisting Financialisation with Deleuze and Guattari http://hdl.handle.net/2381/32895 Title: Resisting Financialisation with Deleuze and Guattari Authors: Barthold, Charles Abstract: This thesis wanted to operate two tasks. First, this thesis sought to perform a description of the contemporary functioning of the economy, that is to say of capitalism. This entailed an analysis of the current financialisation of world capitalism. Second, this thesis wanted to identify a revolutionary resistant subjectivity to financialisation. This implied to look for a subjectivity which could successfully resist the power of finance. The first task, that is to say the description of the contemporary economy, was performed through an engagement with an interdisciplinary and Marxian literature that problematised financialisation as a process related not only to the economy and production, but also to the State, social reproduction and even subjectivity. Marxism allowed me to understand the dynamics of capitalism and the current centrality of finance, which was expressed by the concept of financialisation. However, Marxism was unable to provide a sophisticated political strategy which would be based on a specific revolutionary subjectivity. Marx's oeuvre never provided very effective political strategies. Therefore, the political economy of Marx was often complemented by Leninism as a form of political strategy, based on party politics and the vanguard of the proletariat. However, Leninism was connected to Fordist capitalism. Therefore, a new political strategy was needed in the context of financialisation. The work of Deleuze and Guattari provided a novel conceptualisation of subjectivity which could articulate a revolutionary resistance to financialisation. My revolutionary understanding of the oeuvre of Deleuze and Guattari was situated by an analysis of their reception by political philosophy because alternative interpretations existed. Therefore, this thesis sought to operate a fruitful dialogue, that is to say a resonance between Marx and Deleuze and Guattari. 2015-08-05T13:39:56Z Design and Control of the Brushless Doubly Fed Twin Induction Generator (BDFTIG) using dSPACE http://hdl.handle.net/2381/32875 Title: Design and Control of the Brushless Doubly Fed Twin Induction Generator (BDFTIG) using dSPACE Authors: Bensadeq, Asim Abstract: The aim of this research is to present indirect vector control (IVC) for a Brushless Doubly Fed Twin Induction Generator (BDFTIG) for wind energy conversion. The system is anticipated as an advanced solution to the conventional doubly fed induction generator (DFIG) to decrease the maintenance cost and increase the system reliability of the wind turbine system. The proposed BDFTIG employs two cascaded induction machine sets, which consists of two wound rotor induction machines with their rotors connected in cascade to eliminate the brushes and copper rings in the DFIG. This new machine would ideally have one common rotor, and the two stators to be integrated within one housing. For the practical purpose of this research two separate DFIG's were coupled together to a single prime mover. The dynamic model of the BDFTIG with the two machines' rotors electromechanically coupled in a back-to-back configuration is developed and implemented using Matlab/Simulink. Based on the model, the control scheme for flexible power flow control in the BDFTIG with a bidirectional converter is developed. Independent control of the active and reactive power flow is achieved by a four-quadrant power converter under the closed-loop stator flux oriented control scheme. In the proposed control strategy, the generator speed tracks the reference speed very well, and thus the maximum power extract. Which is the optimum speed derived from the maximum power point tracking of the wind turbine. 2015-08-04T15:32:56Z Early Proetid Trilobites From Northern Europe http://hdl.handle.net/2381/32850 Title: Early Proetid Trilobites From Northern Europe Authors: Owens, Robert Maurice Abstract: All known Lower Palaeozoic proetid trilobites from northern Europe have been examined, and those from the Ordovician of the British Isles and Scandinavia and those from the Silurian of the British Isles and Bohemia are described in detail. Closely related species from other areas are figured for comparison. Members of 23 proetid genera, 8 of which are new, are described and figured. 113 species have been investigated, 36 of which are new. The Lower Palaeozoic proetids have hitherto been poorly understood and neglected, and in this thesis they are comprehensively treated as a group for the first time. With their description and figuring, it is now possible to propose a provisional phylogeny for the earlier Proetidae, and to attempt to seek the origins of many important Devonian genera. Of morphological features, the most useful characters for classification are found in the pygidium. Cephalic characters tend to be less reliable. The rostral plate is always subtriangular or trapezoidal in outline, and in all except one case the connective sutures converge backwards. The preannulus has been found to be restricted to the subfamilies Proetinae and Cornuproetinae. From this study it appears as if at least two main lines of proetid trilobites extend well back into the Ordovician, and there may well be a case in the future for recognising two distinct families. The origin of the Proetidae remains problematical, but they could have their origins in Cambro-Ordovician Hystricurine trilobites, some of which, like the proetids, have a trapezoidal rostral plate. 2015-07-30T17:10:56Z Compositional Style and African Identity: A Study of Modern Nigerian Art Music http://hdl.handle.net/2381/32755 Title: Compositional Style and African Identity: A Study of Modern Nigerian Art Music Authors: Omojola, Olabode F. Abstract: The introduction of European culture and Christianity to Nigeria in the second half of the nineteenth century was to lead to changes in the socio-political, economic and religious features of Nigerian society. Since traditional, pre-colonial, Nigerian music was strongly tied to these features, the introduction of European culture and Christianity also had significant effects on Nigerian musical culture. One important result of the contact between European and Nigerian cultures is the growth of the European-derived idiom of written compositions conceived for presentation on a concert platform. In this thesis, such works which have been written by Nigerian composers (from 1940 onwards) are studied with a view to assessing how the composers have sought to meet the artistic demands of contemporary Nigeria by integrating European and Nigerian elements. The thesis provides discussions on historical developments in nineteenth century Nigeria, musical activities in the Church, and the characteristic features of Nigerian music. These discussions constitute the necessary historical, cultural and musical background to the study of the lives and works of six of the major composers of Modern Nigerian Art music in Chapters 5-11. The last chapter summarises the major findings of the study and assesses the problems and the prospects which the growth of this new idiom faces in Nigeria. The chapter identifies the need for a greater emphasis on the teaching of traditional Nigerian music in secondary and tertiary institutions as an important condition for the propagation and the appreciation of the works of modern Nigerian composers. 2015-07-20T14:07:25Z Re-thinking the Curiosity Cabinet: A Study of Visual Representation in Early and Post Modernity http://hdl.handle.net/2381/32594 Title: Re-thinking the Curiosity Cabinet: A Study of Visual Representation in Early and Post Modernity Authors: Bowry, Stephanie Jane Abstract: This thesis examines the concepts and visual strategies employed within the sixteenth- and seventeenth-century curiosity cabinet – here defined as privately-owned European collections of extraordinary objects – to represent the world. This research also examines how these concepts and strategies are paralleled in contemporary art practice from 1990 to the present in Europe and the USA. As such, it challenges traditional museological interpretations of the cabinet as a mere proto-museum, as well as the notion that the cabinet is obsolete as a form of cultural practice. This thesis primarily focuses upon Northern European collecting practice from c. 1540 - c. 1660, and draws upon artworks, objects and collections as illustrative examples. The thesis also offers a new translation of parts of a seminal text in the history of early collections: Samuel Quiccheberg's Inscriptiones Vel Tituli Theatri Amplissimi (1565), included in the Appendix. During the last two decades, there has been a resurgence of scholarly interest in the cabinet, yet perspectives on early collections remain limited – often to a single interpretive lens. Furthermore, scholarship on the nature of the cabinet's connections with and relevance to contemporary cultural practice is still in its infancy. This thesis contends that the cabinet is best understood as a complex set of practices, related to but distinct from those of contemporary museums, and draws upon the Derridean concept of the spectre in order to demonstrate how the cabinet's practices are echoed within contemporary art practice at both a visual and conceptual level. Ultimately, this thesis contributes a new historiography, theoretical perspective and methodological approach to the early modern cabinet, one which sets it in an appropriate historical context, but also considers the nature of its significance in the contemporary era. Description: Some images removed due to copyright issues. 2015-07-10T13:12:52Z Eosinophilic airways inflammation in Chronic Obstructive Pulmonary Disease http://hdl.handle.net/2381/32546 Title: Eosinophilic airways inflammation in Chronic Obstructive Pulmonary Disease Authors: Eltboli, Osama M. I. Abstract: Background: Eosinophilic airway inflammation (>3% sputum eosinophils) is a feature of subgroup of subjects with chronic obstructive pulmonary disease (COPD). My objectives were to investigate the clinical characteristics of eosinophilic COPD, its stability over time and extent in bronchial tissue, whether it is related to parasite exposure or atopy and whether its persistence is due to abnormal clearance by macrophages. Methods: Subjects were studied that had participated in previous observational studies. The repeatability of sputum eosinophils was measured between 3 monthly visits for 1 year. The extent of eosinophilic inflammation in bronchial tissue was assessed using immunohistology on bronchial tissue from COPD and control subjects. Positive serology for parasites was tested in serum samples for 4 helminth species. Atopy was assessed in the subjects using serum total Ig-E and skin prick test. Eosinophil efferocytosis by macrophages was investigated in vivo using cytoplasmic area of red hue of macrophages and in vitro using apoptotic eosinophils fed to monocyte-derived macrophages from COPD and healthy controls. The dynamics of eosinophil clearance during exacerbations was explored using the red hue technique. Results: Eosinophilic and non-eosinophilic COPD have similar lung function and exacerbation frequency. In eosinophilic COPD the health status is better and bacterial colonisation is lower. This phenotype is stable over time. Airway tissue eosinophilis are increased in COPD subjects with high blood eosinophils and are positively correlated with features of remodelling. Eosinophilic COPD is not associated with helminth exposure, but is related to elevated total Ig-E. Macrophage efferocytosis of eosinophils is impaired in COPD and is associated with the severity and frequency of COPD exacerbations. Efferocytosis of eosinophils by macrophages is increased following oral corticosteroid therapy at exacerbation. Conclusion: Eosinophilic COPD is a distinct and stable phenotype that persists in the blood, bronchus and sputum. Its persistence is partly related to atopy and impaired clearance by macrophages with the latter associated with COPD exacerbation severity and frequency. 2015-07-09T13:31:02Z Thermodynamic characterisation of semi-solid processability in alloys based on AL-SI, AL-CU and AL-MG binary systems http://hdl.handle.net/2381/32538 Title: Thermodynamic characterisation of semi-solid processability in alloys based on AL-SI, AL-CU and AL-MG binary systems Authors: Zhang, Duyao Abstract: The processing window is important for the semisolid processability of alloys. Applications of semi-solid metal (SSM) processing, especially aluminium alloys have been expanding for their excellent mechanical properties. However, the alloys well suited and commercially used for SSM processing today are limited in types. The main purpose of this Ph.D. project is to understand what makes an alloy suitable for SSM processing on both aspects of thermodynamics and kinetics. This research started with a fundamental study of binary alloys based on Al-Si, Al-Cu and Al-Mg systems (wt%): Al-1Si, Al-5Si, Al-12Si and Al-17Si; Al-1Cu, Al-2Cu and Al-5Cu; Al-0.5Mg, Al-3Mg and Al-5.5Mg. These are representative of Si, Cu and Mg contents in commercial alloys used for SSM processing. The Single-Pan Scanning Calorimeter (SPSC) and Differential Scanning Calorimeter (DSC) were used to investigate the liquid fraction changes during heating and cooling of these binary alloys. Thermo-Calc and DICTRA (DIffusion-Controlled TRAnsformations) software have been used to predict the fraction liquid versus temperature taking into account both thermodynamics and kinetics. Comparison of the predictions with experimental data revealed that the simulation results show the same pattern with experimental results in the fraction liquid-temperature relationship. However, the SPSC results are closer to the prediction than DSC curves are, even with the relatively large sample size associated with SPSC. This is potentially a significant result as predicting the liquid fraction versus temperature for the heating of a billet for semi-solid processing remains one of the challenges. The results also suggest that the fraction liquid sensitivity to time should be identified as a critical parameter of the process window for semi-solid processing in addition to the fraction liquid sensitivity to temperature. For microstructure investigation, microanalysis techniques, including Scanning Electron Microscopy (SEM) and micro-indentation testing, have been used on polished sections, and compared to theoretical predictions. In addition, some parts of this project are in cooperation with General Research Institute for Nonferrous Metals (GRINM), which aims to design and develop high performance semi-solid alloys. Thermodynamic analysis (both predictions and experiments) were carried out on thixoformed 319s (2.95Cu, 6.10Si, 0.37Mg, wt%) and 201 (4.80Cu, 0.7Ag, wt%) aluminium alloys. SEM techniques and Transmission Electron Microscopy (TEM) were used for the microstructural characterisation. The results showed that the DSC curves were sensitive to microsegregation in SSM alloys and resulted in a lower liquid fraction than the cast alloys calculated through the integration method from the DSC results. Al2Cu phase in SSM alloys 319s and 201 can be dissolved into matrix up to 0.4 % before melting temperature under 3K/min heating rate when compared with 10K/min heating rate. The DSC scan rate should be carefully selected as higher heating rate can inhibit dissolution of the intermetallic phases during heating leading to less accurate liquid fractions predictions. 2015-07-09T11:09:57Z MicroRNA control of drug-resistance in haematological malignancies http://hdl.handle.net/2381/32535 Title: MicroRNA control of drug-resistance in haematological malignancies Authors: Screen, Michael P. Abstract: miRNAs have been shown to play a role in fundamental cellular processes. They are also involved in drug-resistance mechanisms, which hamper the treatment of many types of cancer, including haematological malignancies. This study sought to uncover mechanisms of miRNA-induced drug-resistance in two haematological malignancies: diffuse large B-cell lymphoma (DLBCL) and multiple myeloma (MM). To this end, profiling of DLBCL and MM-derived cell lines was carried out to identify miRNAs whose levels were altered relative to their respective controls. The expression levels of these miRNAs were then modulated in the cell lines to examine the effect upon cell survival. The miRNA profiling data of the DLBCL cell lines compared to their control "normal" B-cell lines, was then combined with the results of previously performed "translational profiling" in which levels of mRNA translation are compared. Translational profiling identified upregulation of certain DNA damage repair (including BRCA2) and anti-apoptotic (including Bcl-2) proteins in the DLBCL cell lines. Importantly, the miRNA profiling data identified downregulation of miR-34a and miR-146 in the DLBCL cell lines, which are reported to target Bcl-2 and BRCA2, respectively. In GCB-DLBCL patient samples low miR-34a expression correlated with poor prognosis. In MM, the miRNA profile of an acquired multidrug-resistant cell line (8226/R5) was compared with the profile of its parental sensitive cell line and the miR-200 family was identified as upregulated in the resistant line. Overexpression of miR-200b, miR-200c or miR-429 in the parental cell line increased resistance to the proteasome inhibitor bortezomib. The increased resistance was due to direct targeting of the pro-apoptotic protein, Noxa, by the miR-200bc/429 family. Acquired bortezomib-resistant cell lines, which were only resistant to proteasome inhibitors, were then generated. miR-200b was again upregulated in these new cell lines, suggesting that increased expression of the miR-200bc/429 family is a possible mechanism for acquired bortezomib-resistance in MM. Description: The file associated with this record is under embargo for 1 year. 2015-07-09T11:01:28Z The ecology of East African soda lakes: implications for lesser flamingo (Phoeniconaias minor) feeding behaviours http://hdl.handle.net/2381/32533 Title: The ecology of East African soda lakes: implications for lesser flamingo (Phoeniconaias minor) feeding behaviours Authors: Robinson, Victoria Jane Abstract: This thesis investigates the feeding ecology of the lesser flamingo (Phoeniconaias minor). Studies took place at six endorheic alkaline-saline lakes within the East African Rift Valley, which varied in terms of taxonomic composition and biomass, both spatially and temporally. The lakes could be categorised as Arthrospira fusiformis dominated (lakes Bogoria and Sonachi), diatom dominated (Lakes Natron and Elementaita) or 'other' cyanobacteria dominated (lakes Oloidien and Nakuru). From 2009 to 2013, the lake levels were consistently rising with the average biomass reducing concurrently; maximum surface A. fusiformis recorded was > 800 mg L-1 in 2009 at Lake Bogoria, falling to < 50 mg L-1 in 2013. A reduction in average biomass was recorded at all lakes throughout the study period, with the exception of Lake Natron, where higher diatom abundance was recorded in 2011 than in 2009. This study identified 10 distinct feeding behaviours utilised by lesser flamingos at different times of day. Different behaviours were also employed to access different food resources from a variety of niches throughout the aquatic habitat: from the lake's edge, the open water and the lake-sediment interface. Deep water feeding was occurring in higher frequency than recorded previously, at Lake Bogoria where flamingos were exploiting a highly concentrated food resource of sedimented A. fusiformis, discovered during this study. This confirms that deep water feeding behaviours are more common than only being utilised to access diatoms as an emergency food source, as has been suggested. The time spent feeding was negatively correlated with food abundance across the six lakes with lower biomass requiring longer feeding duration, however, at Lake Bogoria a positive correlation was identified, suggesting re-stocking of energy reserves. A positive correlation was identified between the distribution of food resources within Lake Bogoria and lesser flamingo distribution across the lake. Finally, a significant difference was found between flock density when feeding on different food sources (more densely flocked when feeding on A. fusiformis than on diatoms) or through different feeding behaviours. 2015-07-09T10:48:29Z Study of the radiation effects on the Swift-XRT CCD camera in low Earth orbit http://hdl.handle.net/2381/32532 Title: Study of the radiation effects on the Swift-XRT CCD camera in low Earth orbit Authors: Pagani, Claudio Abstract: In this thesis, the damage caused by space radiation on the Swift X-ray telescope CCD is investigated. The analysis reveals the presence of damaged pixels affected by charge traps that results in the degradation of the detector energy resolution. The software developed for the trap mapping analysis is presented. The implementation of the trap corrections recovers a significant fraction of the lost resolution. Data from XRT calibration radioactive sources are analysed to characterise the energy and temperature dependence of the charge losses. The trap measurements are exploited in the attempt to derive the value of the ionisation energy of silicon using a novel statistical method. The large charge losses affecting the damaged pixels are at odds with expectations from CCD irradiation by protons, that should generate single electron defects. Neutrons, instead, generated on board the XRT in the detector aluminium proton shield, may displace multiple lattice atoms, as they interact directly with the nuclei. The two scenarios were investigated exposing the same kind of CCD on board the XRT, irradiated before the Swift launch with 10 MeV protons, to a dose of 14 MeV neutrons comparable to that of the XRT during a few years in orbit, as derived from simulations developed using ESA's space radiation modelling system. A laboratory program was undertaken at the Leicester Camera test facility to investigate the damage caused by protons and neutrons. In both cases, pixels affected by large energy losses are identified and characteristic trap energy levels are derived. In the context of satellite missions using CCDs, the observed spatial nonuniformity of the damage suggests that the classical approach of an average correction for the charge transfer inefficiency applied over the entire detector is not accurate and may produce misleading results. Optimisation of the CCD shielding design is discussed based on this investigation. 2015-07-09T10:33:45Z