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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

'Culmination chromatic density' in the free organ fugues of J.S. Bach

Leatherbarrow, Jane Florence January 2018 (has links)
The term 'Culmination chromatic density' (CCD) is devised for the thesis to describe perceived unusual chromatic harmony which occurs towards the end of a few of Bach's free organ fugues. The thesis seeks to determine the nature of the harmony, to establish if seventeenth and eighteenth-century theorists discuss fugue culmination harmony, and whether composers before Bach wrote fugues with unusual culmination harmony. After establishing an outline organ fugue chronology, historical music theory and fugues before Bach are examined for the purpose of identifying influences upon Bach's fugue culmination harmony. The main body of the thesis is an harmonic and structural analysis by chronology of thirty-six of Bach's fugues, individually and collectively. The analysis establishes fugue structure through tables of thematic entries, and the examination of thematic material, counterpoint, and tonal structure. The analysis also examines the accidentals, which are discussed and presented in graphs. The analysis of intervals gives detailed insight into the use of consonances and dissonances. Figured bass is used in music examples to show harmony and progressions. The analysis establishes that there is CCD in certain fugues of Bach, and that there are specific structural features, procedures and advanced compositional techniques associated with CCD. There is a clear link between incidences of CCD and fugue chronology. CCD is linked with fugue structure; and advanced fugues with CCD possess unique structures, procedures, and harmony. The analysis establishes that Bach uses background structures, an important additional compositional tool which is related to CCD. There is evidence of historical precedent in some aspects of CCD, both from music treatises, and in some fugues of antecedent French, German, and Italian composers. Areas for further research are suggested. Implications are that Bach uses previously undiscovered methods for fugue composition, and that there are potential changes to the established chronology.
412

Transfer of tool affordances in computer vision for robotics

Abelha Ferreira, Paulo January 2018 (has links)
Robots working in constrained environments in the industry have achieved great success for a variety of tasks. Future service robots working in unconstrained domains (e.g. home or hospital) will have to cope with unforeseen circumstances, such as not having the usual tool to perform a known task. They will have to assess the affordances of candidate substitute tools and also how best to grasp and orient a tool (tool-pose) for a given task. Everyday tasks in the home often involve using a tool in non-canonical ways, e.g., the handle of a spoon oriented in the right way to retrieve something from a gap; or a bottle of wine used as a rolling pin to roll dough. It is possible to exploit these similarities between different tools and their tool-poses if the robot can learn by trying different tool-poses and also transfer what was learned to assess substitute candidate tools. Learning and dealing with substitute tools comes naturally to humans and is already present in toddlers and in some animals. Research in cognitive science provides insight into a possible mechanism playing an important role in human concept adaptability: projection. Here we provide an application of this cognitive science idea into the real-world domain of computer vision for service robotics. We show both that projection can be made to work in a real-world domain and that our approach can achieve better results than the closest one in the literature. The two main contributions of this dissertation are: 1. A first approach to bringing the idea of projection from cognitive science into a real-world 3D computer vision domain. Instead of a one-pass assessment from sensor data to abstraction and then to score, we have a bottom-up exploration from sensor data to representation and a top-down selection of best alternatives. 2. A semi-automatic framework for assessing tool affordances and tool-pose starting from unsegmented point clouds and including segmentation, simulation, learning and flexible assessment. These contributions enable us to achieve 69% overall accuracy on five different everyday tasks compared to our closest competitor in the literature achieves only 32% on the same four tasks. These results can be obtained when (a) it is possible to create a simulation for the task (b) it is possible to pre-train the system on 5000 different tools. This dissertation demonstrates that it is possible to bring the projection idea into a real-world domain and that combining top-down pressure with bottom-up search and a flexible representation improves accuracy when assessing tool affordances for service robotics.
413

The place of art in Spinoza's naturalist philosophy

Thomas, Christopher January 2017 (has links)
The lack of discussion on art in Spinoza's works has led to the belief that a) the principles of his philosophy are actively hostile to art, and b) that his philosophy has nothing to offer regarding art's theorisation. This thesis examines the few places that Spinoza refers to art in order to discern three things: I) what Spinoza's thoughts on art are; II) how his views on art fit into the wider themes of his philosophy; and III) how his general philosophical position as well as his specific ideas on art might contribute to new models of theorising art. In Chapter One I develop Spinoza's relational and naturalistic concept of individuation, therein providing the theoretical ground for the subsequent chapters which, following Spinoza, treat the work of art as a complex body that conforms to the rules of individuation as they are developed across the Ethics. Chapter Two locates Spinoza's views on the creative act from what he notes of architecture, painting, and other 'things of this kind' in IIIP2Schol. Here I argue that Spinoza radically naturalises the creative act, deriving it from the complex causal activity of extended substance itself. To this extent art is given in IIIP2Schol as an expression of the complexity of Nature. Chapter Three turns to Spinoza's brief words on art and culture in IVP45Schol to ascertain his position on artistic experience. Here I argue that according to IVP45Schol art's necessity for the wise man lies in its ability to foster affective complexity. Chapter Four turns to that other peculiarly human artefact, Holy Scripture, to identify how 'nonnatural' objects come to be differentiated from merely 'natural' objects in Spinoza's strong naturalism. Finally I end with an appendix that brings Spinozistic principles to bear on a consideration of a poem by Futurist poet Mina Loy.
414

Social polymorphism and social behaviour in sweat bees (Hymenoptera: Halictidae)

Davison, Paul James January 2016 (has links)
I use field observations, experiments and molecular techniques to describe the social biology of the sweat bee Lasioglossum calceatum, and to investigate the mechanisms underlying social polymorphism and body size in this species. I also investigate environmental constraints on sociality, and the impact that workers have on productivity, in the obligate social species L. malachurum. Chapter 1 introduces sweat bees as a study system, and reviews social behaviour within the group. I then provide concise introductions to the study species. In Chapter 2 I show that L. calceatum exhibits latitudinal social polymorphism in the UK, with only bees in the south expressing primitive eusociality. I then describe the social life cycle from continuous field observations, with reference to genetic data. In Chapter 3 in I examine environmental and genetic components of social phenotype in L. calceatum by conducting a field transplant of bees from the north of the UK to the south. Social phenotype is likely to be predominantly determined by fixed genetic differences between social and solitary populations. Chapter 4 examines whether the transition between social and solitary nesting results in saw-tooth size clines in L. calceatum and Halictus rubicundus. Overall, both species exhibit converse-Bergmann clines but not saw-tooth clines. In Chapter 5 I transplant the obligate social sweat bee L. malachurum to the north of the UK, to test whether sociality is constrained by season length. Phenology was considerably delayed such that the life cycle could not be completed. In Chapter 6 I investigate queen quality, productivity and costs of worker production in L. malachurum, by manipulating the number of workers per nest. I show that queens probably incurs costs from producing more workers, and that a possible mechanism is that workers from larger groups may be of lower quality. In Chapter 7 I bring together key findings of the thesis, and comment on future directions.
415

Integrated control of honey bee diseases in apiculture

Al Toufailia, Hasan January 2016 (has links)
The honey bee, Apis mellifera, is important both ecologically and economically. Pests and diseases are arguably the greatest current challenge faced by honey bees and beekeeping. This PhD thesis is focused on honey bee disease control including natural resistance by means of hygienic behaviour. It contains eleven independent experiments, ten on honey bee pests and diseases and their control and resistance, and one on stingless bees. Each is written as a separate chapter, Chapters 4 and 14 of this thesis. Chapter 4: How effective is Apistan® at killing varroa? This shows that Apistan is not very effective at killing varroa, presumably because of resistance. It also shows that a single Apistan treatment resulted in the next treatment being significantly less effective, indicating strong selection for resistance. Chapter 5: Towards integrated control of varroa: comparing application methods and doses of oxalic acid on the mortality of phoretic Varroa destructor mites and their honey bee hosts. This shows that oxalic acid can be highly effective at killing varroa mites under beekeeping conditions in broodless hives in winter. However, varroa mortality is affected by application method and dose. In addition, bee and colony mortality and colony performance are also affected by application method and dose. The results of this chapter shows that sublimation is the best method, in that it gives greater varroa mortality at lower doses, and results in no harm to the colonies. In fact, colonies treated via sublimation had significantly more brood in spring that controls, and lower winter mortality, although this difference was not significant. Chapter 6: Towards integrated control of varroa: varroa mortality from treating broodless winter colonies twice with oxalic acid via sublimation. This shows that two treatments of 2.25 g oxalic acid via sublimation at an interval of 2 weeks in broodless honey bee colonies in winter result in greater varroa mortality than a single treatment, 99.6% vs. 97%. Making a second oxalic acid treatment was not harmful as the performance (frames of brood, queen and colony survival) of the twice-treated colonies over the next 4 months was not significantly different to the once-treated control colonies. Chapter 7: Towards integrated control of varroa: Efficacy of early spring trapping in drone brood. This indicates that trapping in drone brood in spring is probably not sufficiently effective to be able to control varroa populations on its own. It shows that trapping varroa in capped drone cells in early spring is not highly effective at controlling varroa. The first and second test frames of drone foundation removed 44% and 48% of the varroa, respectively. Chapter 8: Towards integrated control of varroa: Monitoring honey bee brood rearing in winter and the proportion of varroa in small patches of sealed cells. This shows that December is the month with the least brood. However, winter reduction in brood rearing varied among years and even in December some colonies still had sealed brood. Although the amounts of sealed brood were low, even a small patch of c. 500-600 sealed cells could contain 14% of the varroa in a colony. This will halve the duration of control provided by an oxalic acid treatment. Chapter 9: Towards integrated control of varroa: effect of variation in hygienic behaviour among honey bee colonies on mite population increase and deformed wing virus incidence. This shows clearly that hygienic behaviour reduces the one-year population growth of varroa in honey bee colonies by more than 50% and reduces the levels of deformed wing virus by more than 1000 times. Chapter 10: Hygienic behaviour saves the lives of honey bee colonies. This shows that hygienic behaviour saves the lives of honey bee colonies with shrivelled wings, a visible symptom of deformed wing virus that is considered a predictor of colony death. Over one year, only 2 of 11 colonies requeened with a non-hygienic queen survived, versus 13 of 15 requeened with a hygienic queen. Chapter 11: Hygienic behaviour by non-hygienic honey bee colonies: all colonies remove dead brood from open cells. This shows that all honey bee colonies are highly hygienic in response to dead or diseased brood in open cells. All larvae killed by freezing with liquid nitrogen and larvae with chalkbrood disease were removed. This was true even for colonies with low levels of removal of dead brood from sealed cells, which would be considered as non-hygienic colonies. Chapter 12: Removal of larvae infected by different strains of chalk brood and other fungi by hygienic and non-hygienic bee colonies. This shows that hygienic and non-hygienic honey bee colonies are highly hygienic in response to diseased larvae killed with different strains of fungus in open cells. Chapter 13: Hygienic behaviour in Brazilian stingless bees. This shows that the three stingless bee species studied (Melipona scutellaris, Scaptotrigona depilis, Tetragonisca angustula) all have high levels of hygienic behaviour, quantified as the removal of freeze-killed brood, in comparison to the honey bee Apis mellifera. In S. depilis there was considerable variation in hygienic behaviour among colonies, and hygienic colonies removed more brood affected by a naturally-occurring disease which we discovered and for which the causative agent remains to be identified. Chapter 14: First record of small hive beetle, Aethina tumida Murray, in South America. This reports the discovery of adult small hive beetles, Aethina tumida, in honey bee, Apis mellifera, hives in an apiary in Brazil, in March 2015. This is the first record for South America of this honey bee pest.
416

Sir George Scharf and the early National Portrait Gallery : reconstructing an intellectual and professional artistic world, 1857-1895

Heath, Elizabeth January 2018 (has links)
This thesis investigates the professional practice of the National Portrait Gallery's first Director Sir George Scharf (1820–95). It is the first focused analysis of his career and influence, within the nineteenth-century art and museum worlds. It attempts to position Scharf in relation to developments in art historical scholarship and the professionalization of museum practice, in the second half of the 1800s. Chapter 1 outlines Scharf's methodology for portraiture research and considers his scientific approach alongside the establishment of art history as a discipline during his lifetime. Whilst exploring Scharf's development of research standards to be carried forward by successors, it argues for his active role amongst a growing contingent of museum professionals. Chapter 2 reconstructs Scharf's social and professional networks, collating the names of individuals with whom he interacted and mapping the physical sites of engagement. It proposes that access to contacts proved vitally important to his official work and that Scharf himself functioned as an influential figure in this sphere. The third chapter concerns the nature of Scharf's relationships with members of the NPG's Board of Trustees. It investigates his early collaboration with two expert Trustees and charts his interactions with consecutive Chairmen of the Board, demonstrating Scharf's increasing authority with regards to Gallery procedures. Chapters 4 and 5 explore Scharf's interventions relative to the organization and interpretation of the collection across the NPG's early exhibition spaces. Chapter 4 argues that an increased capacity for display enabled Scharf to implement a rational hanging scheme, in line with the Gallery's instructive purpose and inspired by contemporary debates over the efficient presentation of public art. The final chapter documents Scharf's efforts to contextualize the national portraits, ranging from manipulating the exhibition environment, to expanding the NPG's catalogue according to a scholarly model. In its examination of George Scharf's career spanning five decades, particularly his engagement with discourse surrounding public art museums in the Victorian period, this thesis aims to make a significant contribution to the fields of museum studies and studies in the history of collecting and display.
417

Using Q method and agent based modelling to understand hurricane evacuation decisions

Oakes, Robert David January 2014 (has links)
A significant minority of at risk residents in the USA do not evacuate from an approaching hurricane when they are advised to by local authorities. This causes unnecessary deaths, injuries and suffering; a situation which is likely to intensify under predicted climate change. This thesis argues that non-evacuation is not fully understood as both the academic and policy framing of the decision to evacuate is centred around technical and socio-economic approaches which assume that risk is objective and “rational” people will evacuate if they have the material means to do so. This thesis argues that rationalities are differentiated and decision making is also a process which is influenced by members of a social network. Therefore there is a need for a more constructivist approach to get a deeper understanding of the subjectivity of hurricane evacuation. In this thesis, the theory of reasoned action is used as the framework of decision making as it highlights the importance of subjective attitudes and subjective norms on behaviour. A mixed methods case study of Hurricane Ike is used to analyse the evacuation of Galveston Island, Texas. Firstly a “Q” study was undertaken with 40 residents of Galveston, which unveiled four distinct subjective evacuation attitudes, demonstrating that people understand hurricane risk in different ways which impact on their decision to evacuate. The results of the Q study were then used to parameterise an agent based model, designed to investigate community level evacuation. The model showed that it is possible to explain island-level evacuation through the combination of subjective evacuation attitudes and subjective norms which can interact to produce emergent, or unpredicted behaviour. This thesis represents a fundamental challenge to positivist approaches and clearly demonstrates the value of a more constructivist approach to understanding hurricane evacuation based on subjective evacuation attitudes and subjective norms.
418

Quantitative image analysis of peripheral nerves in whiplash injury patients

Anantharaman, Kamakshi Pradeep January 2018 (has links)
The research in this thesis has examined the use of texture and shape analysis to characterise Magnetic Resonance (MR) images of peripheral nerves in order to provide a potential quantitative tool for better diagnosis and treatments. Texture and shape can be considered as inherent properties of all surfaces and have the potential to provide sensitive information which cannot be quantitatively perceived by human vision. Texture analysis has been successfully used in image classification of aerial and satellite imagery and the diagnosis and prognosis of several types of cancer. However, to date, it has never been used in investigating peripheral nerve damage. In this thesis, we study the application of texture and shape analysis to the peripheral nerves in the upper extremities of patients suffering from Whiplash Associated Disorders (WAD). Specifically, quantitative texture analysis was performed on MR images of the carpal tunnel which contains the median nerve. The median nerve was studied to identify differences in textural patterns. Texture methods such as: first order features; co-occurrence matrices; run-length matrices and autocorrelation function were applied and their performance was assessed. Texture analysis was also performed to investigate nerve damage in the MR images of the brachial plexus, both in controls and patients. Further, spatial domain shape metrics were used to quantify and study the morphological differences of the median nerve in controls and patients. This highlighted that some significant differences exist between groups and thus could potentially be reliably used in combination with clinical scale metrics to identify possible nerve damage. As MR images contain noise, locating the median nerve accurately to perform image analysis is very important. Therefore, we further investigated the application of an enhanced correlation filtering method that could be trained on images of the median nerve and then applied to detect the median nerve in test images. The Optimal Trade-off Maximum Average Correlation Height (OT-MACH) filter includes the expected distortions in the target in the construction of the filter reference function. The OT-MACH filter was tuned in a bandpass to maximize the correlation peak and thereby successfully locate the position of the median nerve in the carpal tunnel. This study has successfully demonstrated that texture and shape analysis can be used to investigate possible peripheral nerve damage. Further research is required using larger datasets to establish a quantitative image analysis tool to support clinical decision making and thereby improve patient care and treatment outcome.
419

Hygienic behaviour in honey bees

Bigio, Gianluigi January 2014 (has links)
This thesis focuses on hygienic behaviour in honey bees. In beekeeping, brood diseases incur heavy economical and biological costs and are no longer effectively treated with chemicals. Previous research has shown how hygienic behaviour, a trait expressed by c. 10% of unselected colonies, can be effective in reducing the impact and presence of such diseases. Hygienic behaviour is experimentally measured using the freeze-killed brood (FKB) bioassay and can be increased by selective breeding, generating lines of hygienic colonies. Chapter 4 demonstrates that the relative rarity of hygienic behaviour in unselected colonies is not because it incurs a cost via the removal of healthy brood. Chapter 5 - 6 focus on the impact of external factors on hygienic behaviour. Specifically, we demonstrate that the presence of brood, amount of food, and strength of the colony affect hygienic levels (Chapter 5). Chapter 6 shows that hygienic behaviour does not correlate with agressiviness or agitated behaviour. When breeding honey bees, it is possible to exploit instrumental insemination to have complete control over the genetic composition of the resulting progeny. This technique is however laborious and requires particular equipment and training. In Chapter 7 we show that it is possible to obtain acceptable levels of hygienic behaviour without artificial insemination. Chapter 8 illustrates how we obtained the first breeing line of hygienic honey bees through a selective breeding program that saw its first milestone in autumn 2013 when we detected high levels of hygienic behaviour. The results obtained represent the foundation for future research projects. Chapter 9 presents a valid, minimal methodology to keep virgin queens. We tested a variety of methods and factors to determine the best, mos cost-effective way to maintain queens for the week prior their introduction into a queenless hive. The results obtained provide some insights on both basic and applied aspects of honey bee breeding for hygienic behaviour and represent the foundation of what will be an ongoing selection programme towards a disease-resistant honey bee.
420

Cytocidal activity of Cry41Aa, an anticancer toxin from Bacillus thuringiensis

Souissi, Wided January 2018 (has links)
Bacillus thuringiensis (Bt) is a gram positive spore forming bacterium which produces intracellular protein crystals toxic to a wide variety of insect larvae and is the most commonly used biological pesticide worldwide. More recently, Bt crystal proteins known as parasporins have been discovered, that have no known insecticidal activity but target some human cancer cells exhibiting strong cytocidal activities with different toxicity spectra and varied activity levels. Amongst these parasporins, parasporin-3 most closely resembles the commercially used insecticidal toxins and presents the narrowest activity spectrum, showing moderate cytotoxicity against only two cancer cell lines, HL-60 (Human promyelocytic leukemia cells) and HepG2 (Human liver cancer cells). Parasporin-3, also called Cry41Aa, has only been shown to exhibit cytocidal activity towards these two cell lines after being proteolytically cleaved. In order to understand this activation mechanism various mutations were made at the N- or C-terminal region of the protein and the toxicity against both HepG2 and HL-60 cell lines was evaluated. Our results indicate that only N-terminal cleavage is required for activation and that N-terminally deleted mutants show some toxicity without the need for proteolytic activation. Furthermore we have shown that the level of toxicity towards the two cell lines depends on the protease used to activate the toxin. Proteinase K-activated toxin was significantly more toxic towards HepG2 and HL-60 than trypsin-activated toxin. N-terminal sequencing of activated toxins showed that this difference in toxicity is associated with a difference of just two amino acids (serine and alanine at positions 59 and 60 respectively) which we hypothesize occlude a binding motif. Preliminary work carried out on binding showed a lack of correlation between binding and toxicity since toxin binds to both susceptible and non-susceptible cancer cell lines. In an attempt to better understand the mechanism of action of Cry41Aa against these cells, we evolved resistance in HepG2 through repeated exposure to increasing doses of the toxin. Morphological, physiological and genetic characteristics of the resistant cell line were compared with susceptible cells. Toxin was shown to bind to resistant HepG2 similarly to the susceptible line. RNA sequencing identified AQP9 as a potential mediator of resistance but extensive investigations failed to show a direct link. The involvement of certain intracellular signalling pathways were also investigated in order to understand cell responses to the toxin and showed that in response to the toxin p38, but not ERK1/2, is activated and in a dose dependent manner.

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