Tesis sobre el tema "Fields of Research"

The primary purposes of this study were to (1) verify the criteria for selection of variables that are measures of research activity; (2) replicate for 1987 the development of a composite measure of research activity index (RAI) for the top 100 research universities in the United States; (3) cluster the top 100 research universities according to the Carnegie Foundation's classifications and rank each university by its respective RAI within the cluster; (4) evaluate the strengths and weaknesses of the RAI and compare the results to those of previous studies; (5) pilot the development of a component Fields of Science and Engineering Research Activity Index (FSERAI) for the top 100 research universities in two specific fields of science (physical and social sciences) and rank the universities according to their respective component FSERAIs; and (6) examine a productivity quotient for each of the top 100 research universities. A review of the literature provided the eleven variables used in the development of the composite RAI. The statistical instrument used to develop the Research Activity Index Score (RAIS) was a subroutine of factor analysis known as principal components analysis. The RAI scores were produced for each institution and ranked in descending order. Ultimately, two comparisons were made. First, the RAIs for the year 1987 were compared with previous RAIs for the years 1980 and 1985. Second, the RAIs for the years 1980 and 1985 were recalculated exclusive of the personnel variables unavailable for the year 1987. Institutions were then clustered according to Carnegie Foundation classifications and were ranked by their respective RAIs within each category. The same basic design, used to produce the composite RAI, was used to produce the composite FSERAI. Of the seventeen variables initially gathered, eight were used in the derivation of the component FSERAI. Ultimately, 48 institutions were ranked in the physical sciences and 67 were ranked in the social sciences. Lastly, a relative productivity index for each of the top 100 research universities was produced.

Two areas of underwater acoustics are investigated: ocean-bottom scattering and acoustic fields in geometrically dispersive sound channels. The purpose is to describe and provide an understanding of the physical mechanisms in these two areas by comparing analyzed results from ocean experiments with theoretical computations. Experiments using directive 19.5-kHz transducers illustrate temporal and spacial behavior of signals scattered from the ocean bottom. The signals fluctuate, as a function of acoustic geometry, in linear relation to source and receiver motion and to signal frequency. Spacial structure of the acoustic field depends on frequency and acoustic geometry and is independent of motion and bottom roughness. Data supporting these observations are included as well as data showing the effects of bottom type on the scattered returns, that is, the existence of subbottom returns in some data. Volume-scattering-strength profiles are also provided from data obtained in these experiments. Continuous-wave (CW) and impulsive sources covering frequencies 5 to 260 Hz were towed and deployed respectively over ranges up to 3000 km, with reception on fixed hydrophones. Analyses of measured propagation losses of these low-frequency acoustic signals in the dispersive channel provide insights into the nature of the propagation and the acoustic channel. Both the CW signals and the arrivals of the impulsive signals are analyzed in terms of transmission loss, convergence-zone structure, source-motion effects, interference structure, and channel characteristics. The systematic variation (internal tides) of the medium and its influence on the interference field are discussed. The state of modeling, both simple and complicated, is reviewed and compared with results of the ocean experiments. Relationships are provided between this work and the broader field of underwater acoustics. Suggested areas for future research are made.

The thesis provides a background on crystallisation, the effects of applied fields and summarises the techniques used for characterisation and analysis. The study of applied magnetic fields was carried out on three crystallising systems (a) sucrose, (b) lactose and (c) cocoa butter. Both sucrose and lactose were crystallised from aqueous solutions in incubators at 50°C in applied magnetic fields and the resulting crystals compared to the those obtained under zero field conditions. The results for the sucrose study where the magnetic treatment was carried out under static, dynamic pumped and dynamic syphoned conditions domonstrated that changes in phase, crystallinity, morphology and microcrystallinity were a result of the applied magnetic fields and additional strongly bound water was found to be present within the sucrose crystals most likely to be sucrose hydrates. The resulting sucrose crystals were dependant on the type of field applied, the purity of the sucrose solution and the residence time within the applied field. The lactose study under static conditions provided similar results concluding that applied fields resulted in a more controlled crystallisation resulting in increased crystal size, increased crystallinity and changes in morphology. Crystallisation of cocoa butter from the melt, under normal production conditions in applied fields, resulted in changes in morphology and the time taken to reach optimum tempering which were dependant on the type of applied field and the residence time in the applied field.

In this dissertation the question of whether or not a relative extension of number fields has a relative integral basis is considered. In Chapters 2 and 3 we use a criteria of Mann to determine when a cyclic quartic field or a pure quartic field has an integral basis over its quadratic subfield. In the final chapter we study the question: if the relative discriminant of an extension K / k is principal, where [K : k] = l such that l is an odd prime and k is either a quadratic or a normal quartic number field, does K / k have an integral basis?
Ph. D.

Grasses form the basis for the meat, dairy, wool and deer industries, which contribute to nearly 50% of New Zealand exports, and are also an important component of natural ecosystems. Worldwide >100 plant viruses infect grass species and even mild and symptomless infections can adversely effect plant populations through reduced reproductive rates and greater susceptibility to environmental extremes. The only previously published study on viruses in New Zealand’s natural grasslands found that cereal viruses have invaded the native grass flora of the South Island. This research provided an extensive survey of New Zealand native grasses, showing that barley yellow dwarf virus diseases (BYDV, Luteoviridae) and Cocksfoot mottle virus (CoMV, Sobemovirus) are widespread in the North and South islands of New Zealand. Significant findings include seven new virus hosts amongst the New Zealand native flora, the first report of BYDV-PAS in New Zealand, detection in Hierochloe redolens of a novel virus in the Luteoviridae family (proposed name BYDV-To), and in Festuca novae-zelandiae a novel dsRNA virus possibly belonging to the Partitiviridae family. New virus host reports in New Zealand include CoMV in Poa anceps, P. cita, F. novae-zelandiae, and Chionochloa rubra; BYDV-PAV and BYDV-PAS in Microlaena stipoides and Dichelacne crinita; BYDV-MAV in P. cita, F. novae-zelandiae and H. redolens; and CYDV-RPV in P. cita and M. stipoides. Molecular techniques for virus detection and identification were developed or improved during this study. Phylogenetic analyses of viral coat protein sequences from native and exotic grass species indicate either frequent or recent virus movement into native ecosystems, and multiple virus introduction events in New Zealand. The likely origins of the virus species are discussed. Two CoMV variants were identified, one of which caused severe necrosis in susceptible cocksfoot cultivars. Reciprocal aphid transmission of BYDV-PAV using cereals and native grasses showed that although transmission to natives was low, the efficiency of transmission from natives to cereals was comparable to that between cereal species, suggesting virus adaptation to the cereal host species. The findings from this study are discussed in respect to disease management and bio-security in New Zealand, and recommendations are made for future research.
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This thesis examines the role of primary school principals as they undertake their role as educational leaders. Part One summarises theories about leadership and places principals' educational leadership in context. Leadership is defined as a social process whereby principals blend biography and context to reconcile positivist, systemic requirements and recommendations with appropriate localised, and individualised, expectations and aspirations. Part Two outlines an ethnographic methodology that justifies a process to gather and analyse data on the work of three principal subjects. This material is presented in cameo form and supported by questionnaire data from a further group of principal colleagues. Principals' leadership is identified as the interpretation of expectations and resources that results in particular actions. This interpretation is sourced in both context and personal biography. Part Three consists of data analysis and findings. The influence and interplay of context and personal biography are outlined. Conclusions are drawn as to the differences between leadership and management practices, and specific leadership activities performed by principals are identified. This leads to a clarification of leadership as a process of control (as opposed to power) that defines, rather than accommodates, the rules of realisation as to appropriate action. Recommendations are made regarding further study into the issues of personal identity, leadership style and the urgent need for principal pre-service and in-service professional development.
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The improvement of teaching is now recognised to be a key to the sustained improvement of student achievement. Teacher appraisal, a central element of performance management, is intended to improve the quality of teaching (and therefore learning). This thesis examines whether teacher appraisal is achieving this purpose, through three empirical studies. This thesis begins with a discussion of the context of teacher appraisal in relation to education reform of the last two decades. A normative model of teacher appraisal, one that focuses on data-based inquiry into student learning, is outlined, and the emerging education context in relation to that model is examined. Three studies, which explored schools' appraisal documents, appraisal discussions and teachers' appraisal goals, are presented. The first study, a document analysis, investigated the emphasis on student learning in the statements of purpose in 17 primary schools' appraisal policies, and the emphasis on student learning in the performance indicators developed to assess teachers against the professional standards. Results showed that while improved student learning was an intended purpose of schools' appraisal policies, the indicators that were used to evaluate teachers seldom focused directly on student learning.The second study examined whether data-based inquiry into student learning occurs in appraisal discussions, and the reasons for the level of reported inquiry. Eleven practitioners (four appraisers and seven appraisees from three schools) were interviewed about their most recent appraisal discussion to investigate whether student learning was a focus of the appraisal discussions and whether student achievement data were referred to in those discussions. Findings showed that appraisal discussions typically focused on teacher practices without exploring connections between those practices and the impact they have on student learning.Only one of the eleven teachers described a discussion that included talk specifically about student learning. Furthermore, there were no reports of reference to student learning data in appraisal discussions. There was, however, a particularly positive response to the suggestion that appraisal should, and could, focus on student learning and on data relating to this learning. This study also highlighted the considerable influence of appraisal goals in determining the content and scope of appraisals. In the third study, 68 teachers from eight schools responded to a questionnaire about their appraisal goals to establish the extent to which teachers' appraisal goals focus on data-based inquiry into student learning. Less than five per cent of goals were found to refer to student outcomes. The vast majority focused on teacher processes and behaviours. Goals also tended to be vague, rather than specific, and were not explicitly challenging. Findings across the studies suggest that only limited attention is given, in critical elements of teacher appraisal, to student learning. The final chapter of the thesis explores two key strategies for closing the gap between current appraisal practices and the 'appraisal for learning' approach argued for here - an approach that focuses on teacher learning about student learning and that is based on evidence. The first strategy involves alignment within appraisal elements, and to initiatives beyond appraisal. The second strategy is capacity building to ensure that personal, interpersonal and organisational capacities necessary for 'appraisal for learning' are developed. This research shows how teacher appraisal policy and practice has been a missed opportunity to improve teaching effectiveness and how it could be reshaped in ways that maximise student learning.

The immense potential of language, for learning, building relationships, as the embodiment of culture, for an understanding of the world and for expressing 'self', is the underlying theme of this thesis. One less apparent aspect of the language of children is their private speech. In this thesis the research questions focus on whether children from diverse language backgrounds attending English-speaking kindergartens use private speech. Further, if so, what is the context, who is present when it is used and is there a response from the person or people? These questions are primarily addressed through observations of eight children as well as recordings of their private speech. An understanding of the context is supported through interviews with the parents and teachers in the kindergartens. The expectations for this research were largely based on the work of Vygotsky, and adapted to the natural, 'free play' environments of the kindergartens. It was expected that children from diverse language backgrounds in English medium kindergartens would use private speech in their own language. While the children did use private speech (unlike the results from Vygotsky's research) they talked to themselves in English using the language that they had acquired from the community, from the media, from their experiences at kindergarten and in some cases from their families. Based on Krafft & Berk's categories of private speech, a significant focus of this research is the categories of private speech that were used by individual children. These findings pose interesting insight into the experiences of the children. This research has shown the child's remarkable ability to tune into the language and culture of context and to do so not only in relation to the socio-cultural context but also through thinking and acting. This study has also provided insight into the early childhood environments and the experiences of the teachers. As the first known research into private speech/self-talk in early childhood in Aotearoa New Zealand it can serve as a spring-board for further research to enhance our understanding of the child's thinking and learning through private speech.

The outcome of demographics which point to a rapid increase in the number of older adults in the population has been widely debated in the literature. However, it has been examined primarily from the perspective of an unrealistically optimistic or unduly pessimistic view of the future, with few attempts to provide other alternatives. This thesis is structured in three sections. The first backgrounds the context of the research question, the relevant literature, the prospect of gender bias in that literature and the historical development of government policy towards ageing. The second section presents a theoretical perspective for social change, examines the development of social movements and puts a case for a new social movement arising out of the increasing number of older adults and supporting educative processes. The third section reports on empirical research based on interviews in Australia and New Zealand with leaders of organisations involved with older adults and focuses on drawing conclusions from the research in relation to the research question. The theory proposed in this thesis is based on the premise that an opportune time in history exists for older adults to contribute to social and political change. However, for senior members of society to undertake this role will require education in some form, to act as an agency or catalyst to initiate an organised social movement. Findings of this research support the view that the majority of older adults remain fit and healthy and do not conform to the medicalisation approach to ageing on which government policy and, to a large extent, public attitudes, have been formed. While there would be problems of organisation in the formation of a new social movement there are no insurmountable obstacles to overcome. The greatest difficulty would seem to lie in overcoming inertia, sectional interests, generating the leadership and developing innovative and imaginative educative processes.
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This thesis explores reasons for New Zealand’s problematic tail of literacy underachievement and suggests one way to address the problem, is for schools to operate as learning organizations. A qualitative research design was used to identify elements of organizational learning in the practices of three very different schools identified as improving the students’ learning outcomes. The research methods included semi-structured interviews, team meeting observations, an anonymous questionnaire and document analysis. An analytical framework identifying five elements of organizational learning, developed from a review of the organizational learning literature, was used to evaluate each school’s ability to learn about their teaching and learning programmes as a result of reviewing students’ achievement information. The research findings identified elements of the organizational learning framework in the practices of all three schools. It was found that whilst the elements of the framework were necessary, the entirety of the framework was most significant in facilitating organizational learning. In order for the schools to learn to improve the learning of their students, they needed to have a well defined infrastructure for the collection, collation, analysis and use of student achievement information. The occurrence of the infrastructure alone did not, however, facilitate organizational learning. The school leaders and teachers needed to apply the appropriate curriculum content, pedagogical and assessment literacy knowledge to the assessment data in order to make sense of it and to use the information to review and refine their teaching and learning programmes. The acquisition of appropriate levels of professional knowledge appeared to be facilitated within a culture where teachers felt safe and confident to challenge and be challenged in their collegial discussions about students’ learning. Rigorous collegial discussions appeared to foster team learning and to be leader driven. When the appropriate professional knowledge was not available within the organization, learning only appeared to occur when the necessary expertise was accessed from the external environment.

Active labour market programmes are an important component of government labour market policy internationally and in New Zealand. The growth in unemployment, and in particular male and long term unemployment, since the mid 1980's in New Zealand have contributed to the enhanced role of active labour market programmes in government policy. In the early 1990's the New Zealand government introduced a menu of interventions including subsidy, work experience and training programmes. Concomitant with this development has been increased pressure from political, business and social groups to assess the effectiveness of this approach in lowering unemployment. The aim of this thesis is to evaluate the effect of active labour market policy utilised in New Zealand from 1989 to 1997. Whether or not these active labour market interventions were beneficial to those males who participated in them, the effect of treatment upon the treated, is the parameter estimated. The range of programmes makes it possible to analyse a number of programme evaluation issues. These include the overall question of the impact of subsidy, work experience and training programmes in general, but also other specific research questions. In particular the range of subsidy programmes makes it possible to identify that subsidies to private sector firms are more effective than those to public sector organisations. The effectiveness of start-up subsidies for the unemployed are also evaluated and found to be beneficial. The effects of participation upon selected education and ethnic groups are also estimated. Since there is no one estimation approach that works in all circumstances, both regression and matching estimators are used. In order to achieve this it is necessary to create two estimation datasets as the data requirements vary for each technique. The main findings from the research are that participation in active labour market programmes is beneficial in reducing the length of time that participants are registered as unemployed. Work experience programmes have the largest impact, followed by subsidies. The effect of training programmes is smallest. The major beneficial effect occurs in the year following participation and then reduces in subsequent years. There are also some important methodological findings, including the sensitivity of results to the time frame, to the datasets chosen, and to the estimation techniques used.

This study is about an educational experience, which encompasses a range of educational knowledge and skills. It is an experience that is relatively unknown in educational research terms. It is also ct comparatively 'secular' educational experience within a 'religious' institution, the Congregational Christian Church of Samoa (CCCS). The Pastor's School (A'oga a le Faifeau) system teaches children to read and write, employing both Palagi and Fa'a Samoa frameworks. The study is also a positive response to the critical and sometimes negative historical treatment of the church and the Fa'a Samoa, especially in their role in the Samoan child's critical literacy experiences. In the light of the underachievement of Samoan children (especially in literacy-reading and writing), this thesis makes two arguments. They are: i) The Pastors' Schools are an important educational system that have escaped attention but which have profoundly significant educational content and impacts. ii) There is a literacy problem in New Zealand that the A'oga a le Faifeau could address for the reported underachieving Samoan children. The content of the A'oga a le Faifeau syllabus for example, includes the teaching of reading, writing, arithmetic, religious and general knowledge, and the Fa'a Samoa This knowledge forms part of the semantic resources, and literacy skills and expertise, which could prepare children for school because some of those knowledge and skills have spans to school-based literacies. One of the A'oga a le Faifeau's most significant educational impacts is the maintenance and retention of the Samoan language.

'Public Choice Theory' is defined by its proponents as 'the application of economics to politics'. This thesis attempts to describe Public Choice Theory in its component parts and as a coherent and potent contemporary factor in the political and educational scene. The methodologies used are Foucauldian 'genealogy' and 'immanent critique', that is, the theory is examined in its historical context and in terms of its own logic. The process by which this theory has affected the educational situation in New Zealand is examined, and set in the context of the wider application of economics to politics in this country generally. Some of the major policy documents concerning Education are read closely in order to identify the extent of the Public Choice Theory influence on them, Whilst Public Choice Theory is commonly associated with the 'New Right' it is also the key element of 'analytic Marxism'. Whether from 'left' or 'right,' Public Choice Theory, as a basis for the content or organisation of education is presented as a historically contingent theory, making dubious claims to scientific validation, and bringing about consistent changes in the nature of education and the construction of persons engaged in it.

The purpose of this two year cross-sectional and longitudinal study was to examine the reading and language of severely and profoundly deaf children over two years. The focus was on reading and language achievement, measured by standardized tests and the process of reading demonstrated when engaged in reading prose. The children were the entire population of severely and profoundly deaf, aged from 5 to 10 years at the commencement of the study, who had no other educational handicaps. They were being educated within a Total Communication programme at the Kelston School for Deaf and associated unit classrooms. Reading achievement was assessed by the Gates-MacGinitie Reading Assessment Test on three occasions, each one year apart. Reading achievement was also assessed by documenting accuracy and comprehension (retelling) when reading natural language texts. Language achievement was measured using the Grammatical Analysis of Elicited Language (Moog and Geers, 1979, 1980). The relationship between reading and language achievement was established. The reading of natural language stories was analyzed to establish the pattern of errors (miscues) on text at two levels of difficulty for the reader. Categories of semantically appropriate, syntactically appropriate, grammatically similar, the omission of inflectional morphemes, fingerspelt miscues and signing errors were established. Comparisons were made between age groups, proficiency groups(High and Low) and across developmental levels. Cloze passages were also analysed to assess the use of contextual information by these readers. Analyses of Variance (ANOVA) were undertaken for each miscue category in the signed reading, classified by age and proficiency of the reader, and difficulty of the text. Analyses of variance (ANOVA) were undertaken for the miscue categories classified by reading level, and the cloze exercise substitution classified by age and proficiency of the reader. Observations of classroom reading instructions were included to document the environment within which the children were being educated. Six individual case studies, three high progress and three low progress, were also analyzed. The findings suggest that reading achievement of these severely and profoundly deaf readers is still low. This is consistent with previous studies but achievement in comparison with earlier New Zealand data and data from surveys in the U.S. was slightly higher. This study supported previous research that suggested that standardized tests of reading do not adequately measure the reading achievement of deaf readers. High positive correlations (r ≥.90) between reading and language achievement were interpreted to be bi-directional and suggestive that higher rates of engaged time in reading could facilitate greater reading and language development. An integrated/interactive model most appropriately described the process of reading for these deaf readers as for hearing readers. Like hearing readers these deaf readers, at all ages and both high and low progress, were able to utilize contextual cues, and textual cues as they interacted with text. However, several unique differences in the process of reading have important implications for instruction. Low levels of syntactic cues during signed reading, it was suggested, reflect the readers use of their language in use and sensitivity to task factors. Fingerspelling was demonstrated to be a potentially useful strategy that was used at a significantly higher rate by High Progress readers. High Progress readers were more able than Low progress readers to use strategies ensuring fluency in order to construct meaning from texts Observations of classroom reading indicated that the rate of engaged time in reading was not high and that although the teachers espoused a meaning-emphasis some practices in the classroom did not foster independent problem solving readers. The educational implications of the data were discussed.

Phonological awareness is one of the most important metacognitive skills needed for literacy development. However, the relationships between preschool phonological awareness and pre-literacy skills are only just beginning to be examined. An important area is the study of potential precursors to phonological awareness. The current research proposed that phonological awareness develops along a continuum of linguistic awareness beginning with syllables and moving towards the smallest level of the phoneme. In the current research, potential precursors were examined in two studies. The first study was an examination of preschool phonological awareness in a sample of 110 New Zealand four-year-old children with no formal literacy instruction but who had a range of pre-literacy skills including 12 children who could read one or more words. The second study examined how literacy instruction influenced the development of phoneme awareness by independently assessing the role of learning to read and the role of learning to spell by teaching non-readers to read 8 CVC words or to spell the same 8 CVC words, but not to read and spell. The results found that rime and phoneme awareness both contributed to a latent variable of phonological awareness and that they each had different potential precursors. Receptive vocabulary explained the most variance in rime awareness with a small association of letter-name knowledge and own-name spelling while rime awareness developed more in children who learnt new words in the intervention. Rime awareness contributed to phoneme awareness along with letter-sound knowledge. When children were taught to read using blending this led to task specific phoneme awareness gains only. Phoneme awareness did not contribute to word-learning in the experimental conditions, with the only learning occurring in the spelling conditions. Letter-name knowledge had a relationship with the acquisition of orthographic representations. Letter-sound knowledge had a relationship with phoneme and letter-level attempts at unfamiliar words. This suggests that children with good letter-name and letter-sound knowledge have both orthographic knowledge and alphabetic strategies available in early word reading and spelling. Results are discussed in terms of their theoretical and practical implications emphasising the role of alphabet knowledge in early literacy acquisition.

This thesis using oral historiographic techniques examines the changing role and function of a teachers' union during changes in the nature of a national State which can also be related to changing forms of capitalism. The teachers' union is New Zealand Post-Primary Teachers Association (the secondary school teachers' union) and the period of particular focus is between 1983 and the beginning of 1993. This is the period of a crisis in the New Zealand State during which the character of the national State was moved from what has been described as a 'wage earners' Welfare State towards a more residual form providing a 'modest safety net'. The financial and the labour market were deregulated to become more free of direct State involvement. The administration of education was changed and the individual schools' elected Boards of Trustees were made responsible for the provision of schooling. The role of PPTA in the State is moved structurally in this time. As a professional association before the changes, PPTA had both opportunity for input into the mandate of education, as well as the possibility of creating implementation pressure through political action. As a bargaining agent, the input role of PPTA to decisions in education was limited to addressing members' concerns at the school level. The restructuring of education and of the labour market, PPTA was both an object to be acted on and a participant obstructing the changes. This thesis presents what is a PPTA view of those changes. PPTA formed a central part of the education structures which were to be transformed by the economic liberal project. The survival of PPTA demonstrates the extent to which the project was not completed and the resistance of PPTA was one of the reasons why the project in education could not be completed. The thesis is in three parts. Part one is a regulationist-derived periodisation of the historical development of the New Zealand wage earners Welfare State and education. This is followed by a consideration of the economic-liberal challenge to this State Part two considers the development of PPTA's professional project and the possibilities presented through different arenas. Part three focuses on the changing nature of the State labour market policy and PPTA's activity in that. The changing strategies and tactics of PPTA's 'professional project', the thesis argues, occur under changing political conditions and are an example of Offe's concept of rational opportunism

This thesis investigates and analyses the Report of the Commission on Education in New Zealand,1962, also known as the 'Currie Report', paying particular attention to the policy process surrounding the written and oral submissions. Views expressed during the submissions and their ideological basis are related to wider power relationships within society. The submissions emanating from outside the Department of Education are revisited as well as the departmental submissions to establish whether there are any grounds to challenge the consensual, liberal interpretations that have been attached to this important New Zealand historical educational document. The issues raised and avoided in the submissions coalesce around specific themes, which are related to the broader issues of the development of New Zealand educational history. Attempts to counteract, mute and marginalise dissent and to encourage optimal social control are witnessed in the organizational structure of the commission and in its methods. The interaction and networking of key participants is studied and the important inter-relationship between central bureaucratic interventions and powerful educational pressure group activity points to the continuing operational success of central government processes. The often competing forces of provincialism and centralism in New Zealand education underlie many of the conflicts surrounding educational change. Religion, race, gender and class are forces that continually interact to create legitimation crises. The governmental attempt to minimise or at least rationalize these socially contested differences in education from 1960-1962 is the subject of this thesis. An analysis is made of the process by which public dissatisfaction regarding education in the fifties and sixties was mediated and largely marginalised by the educational bureaucracy. This is done by a thorough examination of the interaction of pressure groups, unions, media and governmental agencies during the two year submissions to the Commission on Education 1962. The distinction between the commission's report and the submissions and interrogations leading up to the report is important, as the primary data extracted from the primary resource material in the submissions, at times, contradicts the departmental view as expressed in the report itself. In this way it is hoped to move beyond the rhetoric that informs previous commentaries and move closer to an interpretation based upon the primary data.

This investigation explores the reactions to Darwinism in the format and informal education of New Zealand society. The subsidiary purpose is to look at some implications for formal education. Many of the reactions have focussed on distortions of the Darwinian theory of evolution with the form of reaction to Darwinism being centred on different views of humankind. The various group interests have caused different aspects of Darwinism to be highlighted particularly when groups feel their interests are under threat. Using aspects of an "HS3" historical survey technique i.e. the history of the public reaction to an aspect of science and science teaching, key features of this debate are set in context. This context is then used to show that creationist objections and social Darwinian interpretations share many characteristics with their overseas counterparts. A philosophical analysis of the positions taken supports a charge that New Zealand creationist science is partly non science, and partly bad science. It is also shown that confusion has been created when groups have debated issues from different perspectives including cultural perspectives. In particular there has been a lack of communication as various creationist groups, using different research bases, and political, economic and legal institutions, have adopted generalist conservative positions, highlighted metaphysical and ethical considerations and drawn on creationist science literature to support the science of their case while pro-evolutionist groups have adopted specialist liberal or progressive positions, concentrated on the logic and epistemology of the debate and have drawn on mainstream science literature. Finally some implications have been drawn from this analysis of the different reactions, and recommendations have been made for future teaching of evolution and related concepts.

The nature of professional expertise has been widely debated in the literature. However it has been examined primarily from a dichotomy of perspectives - either from an experiential or a cognitive focus, without the attempt to integrate these, and other aspects of expertise, into an integrated and coherent model. This research is structured in two sections. The first part incorporates a philosophical discussion, which advances an integrated model of professional expertise. The second part uses a case study focused on the field of medical imaging to illustrate and refine the model. Ten professionals identified as experts in the various sub-specialties within medical imaging were guided through a sustained period of interviews and logging of critical incidents in order to elicit in-depth data in relation to the process of expertise. Findings showed that while expertise is situated in the context of practice, it incorporates several dimensions working together in an integrated, seamless fashion through the medium of the individual practitioner. The proposed model integrates five main aspects, namely: knowledge base; cognitive processes; internal integrative processes; interpersonal relationships; and professional practice. That is, it is a synthesis of a particular knowledge base, the cognitive processes, personality and internal processes of the practitioner. It manifests through, and builds on, interpersonal relationships with clients and other professionals, and is expressed through the actual doing of professional practice. It is through the reflexive examination of practice and management of change that professionals may transform these five integrated aspects into the qualitative state of expertise. One of the implications of these findings for higher education are that institutions providing professional education need to value all the dimensions of expertise and their effective integration in order to promote the learning required to advance professionals towards this level of practice.

This is a study of a) the nature and incidence of independent learning defined as "knowing how to generate and direct the processes of learning...*(see p.3) in new entrant classroom settings and, b) the nature of the teacher-child interactions associated with such independent learning. Systematic observation was used at school entry and three months later, to identify aspects of independent learning and the associated teacher behaviours. Six categories of child directed acts identified the range of behaviours from which independent learning could be inferred. Each category of teacher behaviour that appeared to facilitate independent learning in children was developed as a "mirror image" of each category of child directed acts. The teacher and four children in two new entrant classes were observed over the whole day for five days during two observation periods, one at the beginning of Term three and the other after 12 weeks. Each class was involved in normal classroom activities that covered the whole curriculum. The children were engaging in a considerable amount of independent learning on entry to school and three months later. Many facilitative teaching acts occurred in the interactive style that was demonstrated in all aspects of the curriculum. The teachers spent a considerable portion of teaching time assisting children in one-to-one teaching situations and in small groups, encouraging their responses and fostering and supporting independence in their learning. There was some difference observed between teachers in the attention given to different categories and in the facilitative behaviour occurring in one-to-one interactions and small group teaching interactions. A way of teaching emerges that differs from a teaching agenda determined by didactic, traditional instruction. The two teachers were deemed to be using the children's agenda to foster and support them in independent learning in the various curriculum areas. Some of the practical and philosophical features of the New Zealand education system that may contribute to this particular style of teaching are discussed. The theories of learning and teaching deriving from this study place a value on independent learning (as here defined) in new entrant children and on the teacher’s role in providing opportunities for it to develop. Independent learning a) ensures the continuation of learning at times when the teacher is directly engaged with other children, and b) derives from a teacher expectation that children will be able to actively process ideas and make some decisions about their learning. It engenders a power in children that sustains the momentum of learning.

This thesis investigates the problem of how to speed up the process through which professional educators learn how to significantly improve disadvantaged students’ academic achievement. The problem is addressed through three questions: (i) What are the most effective national and international examples of school improvement? (ii) What is the condition of the evidence base for making claims of effectiveness? (iii) What can be learned about developing and implementing effective school improvement from those national and international examples? The thesis begins by searching international and national school improvement literature to find those initiatives with the strongest evidence of effectiveness. One initiative in England (the National Literacy and Numeracy Strategies) and four initiatives in the United States (Success For All, Direct Instruction, The School Development Programme & a district-wide reform in New York District #2) were considered to have strong evidence of effectiveness. Two initiatives in New Zealand (the Numeracy Development Project & the Strengthening Education in Mangere and Otara project commonly called SEMO) had evidence that showed promise. It is argued that patterns of investment in different types of evaluation and ease of access to achievement information account for the difference between the strong international evidence and promising evidence in New Zealand. A series of investigations in the middle of the thesis focus on the processes set up in the initiatives to help practitioners learn effective reform practices. Three models of learning processes are developed which reveal a strong preference for vertical learning in England and the United States and a more balanced vertical-horizontal learning preference in New Zealand. Despite those contrasts, three characteristics were found to be common to all seven effective initiatives. They are a sharp focus on instructional improvement, a set of standardised practices, and, learning connections to transfer the reform ideas into practice. The latter part of the thesis transforms those three characteristics into a theory for schooling improvement which contribute to a faster and more effective reform process.

In this thesis I portray through a history of music and art education in New Zealand the forms knowledge production took in these subject and the discourses within which they were embedded. This enables a more comprehensive understanding of curriculum and unearths connections with what Lyotard (1984) described as 'grand narrative' used to legitimate knowledge claims and practices at certain historical moments. Through such histories we may chart the progress of European civilization within the local context and provide the historical raison d'être for the present state of affairs in music and arts areas of the New Zealand curriculum. Curriculum and its 'reform' representing in part the distribution of public goods and services, has been embroiled in a market project. I seek to expose the politics of knowledge involved in the construction of the notion of The Arts within a neo-liberal policy environment. This environment has involved the deliberate construction of a 'culture of enterprise and competition' (Peters, 1995: 52) and, in the nurturing of conditions for trans-national capital's freedom of movement, a withdrawal from Keynesian economic and social policy, an assault on the welfare state. The thesis delves beyond the public face of policy-making. It follows and scrutinizes critically the birth of The Arts in the New Zealand Curriculum to the production of the first draft of the proposed policy presented by the Ministry of Education in 1999. I examine it as a site of the 'accumulation of meaning' (Derrida, 1981: 57) through a discussion of the history of meaning of 'art' and 'art' education. There is much of value in the Draft document. In particular, the arts have been invested with a new intellectual weight and the professionalism, passion and dedication of those involved in its writing shines through in each of the subject areas within the arts. However, through a process of analysis, I will show that there has been, in fact, a fashioning of a new container for the isolation of artistic knowledge. This is despite official sentiments mentioning possibilities within the document for flourishing separate Music, Art, Dance, and Drama education that implies increased curriculum space. The Draft Arts (1999) document both disguises and rehashes the 'master narrative' of universal rationality and artistic canons and is unlikely to work towards revitalising or protecting local cultural identities though not through lack of intention. I use Lyotard's notion of 'performativity' to critique notions of 'skills' and their 'development' which are implicitly and explicitly stated within the 'levels' of development articulated in the Draft Arts (1999) document. It is argued that this conflation works to enforce cultural homogeneity. There are clear dangers that the Draft Arts' (1999) conception of 'Arts Literacies' might operate as mere functional literacy in the service of the dominant culture's discourse of power and knowledge-one which celebrates the art-as-commodity ideal. It is argued that the Education Ministry's theoretical and epistemological construction of The Arts as one area of learning is unsound, and in fact represents a tightening of modernism's hierarchical notion of culture. New Zealand, now post-colonial or post-imperialist, both bi-cultural and multi-cultural, is situated on the south-western edge of the Pacific Rim. Culturally, it now includes Pacific Island, Asian, and new immigrants, as well as Maori and people of European descent. This therefore necessitates aesthetic practices which, far from promoting a set of universal principles for the appreciation of art - one canonical rule or 'standard' - recognise and reflect cultural difference. Merely admitting cultural difference is inadequate. By working away critically at the deeply held ethno-centric assumptions of modernism, its selective traditions concerned with 'practices, meanings, gender, "races", classes' (Pollock, 1999: 10), its universalising aesthetics of beauty, formal relations, individuality, authenticity or originality, and self-expression, of 'negativity and alienation, and abstraction' (Huyssens, 1986: 209), it is possible to begin to understand the theoretical task of articulating difference with regard to aesthetics. The development of the arts curriculum in New Zealand is placed within the modernism/postmodernism and modernity/postmodernity debates. These debates have generated a number of questions which are forcing us to re-examine the assumptions of modernism. The need for the culture of modernism to become self-critical of its own determining assumptions in order to come to understand its cultural practices, is becoming an urgent theoretical task, especially in disciplines and fields concerned with the transmission of acquired learning and the production of new knowledge. The culture of modernism is often taken as the historical succession of twentieth century avant-gardes (B. Smith, 1998) yet the culture of modernity, philosophically speaking, strictly begins with René Descartes several hundred years earlier, with a pre-history in the Florentine renaissance and the re-discovery of Graeco-Roman artistic and literary forms going back to the thirteenth century. Aesthetic modernism identifies with consumer capitalism and its major assumptions are rationalist, individualist and focus upon the autonomy of both the 'work of art' and the artist at the expense of the artwork, its reception and audience within its localised cultural context. The ideological features of humanism/liberalism - its privileging of the individual subject, the moral, epistemological and aesthetic privileging of the author/artist - are examined as forces contributing to modernism's major values (or aesthetic). Such approaches, it is argued, were limited for dealing with difference. The security and reproductive nature of modernistic approaches to curriculum in the arts areas are destabilized by thinking within the postmodern turn, and the effects of the changes questioning the basic epistemological and metaphysical assumptions in disciplinary fields including art/literature, artchitecture, philosophy and political theory, are registered here, within the field of the education in and through the arts. In a seminal description or report on knowledge, Jean-François Lyotard defines postmodernism as 'incredulity towards metanarratives' (1984: xxiv). Postmodernism, he argues, is 'undoubtedly part of the modern', 'not modernism at its end but in its nascent state and that state is constant (1984: 79). After Lyotard, postmodernism might be seen, therefore, not just as a mode or manner or attitude towards the past, but also as a materializing discourse comprising a dynamic reassessment and re-examination of modernism and modernity's culture. The thinking subject (the cogito) seen as the fount of all knowledge, its autonomy, and transparency, its consideration as the centre of artistic and aesthetic virtuosity and moral action, is subjected to intellectual scrutiny and suspicion. The need for an aesthetics of difference is contextualised through an examination of western hierarchies of art and the aesthetics of marginalized groups. I use the theories of poststructuralist, Jacques Derrida and Jean-François Lyotard, to examine the concept of difference. These theoretical inspirations are used as methodological tools for offsetting the privileging of the liberal individual and individualism. Rather than the mere consideration of difference in curricula, I seek to insert and establish the principle of an aesthetics of difference into relations of pedagogy and curricula. The implications for professional practice resulting from a recognition of a politics of representation are examined and a politics of difference. I argue that art education in all its manifestations can no longer avoid the deeper implications of involvement with representation, including forms of gender, ethnicity and class representation as well as colonial representation. The Western canon's notion of 'artists' and their 'art', often based upon white bourgeois male representations and used in many primary school classrooms, are part and parcel of 'social and political investments in canonicity', a powerful 'element in the hegemony of dominant social groups and interests' (Pollock, 1999: 9). Difference is not appreciated in this context. School art, music, and drama classrooms can become sites for the postmodern questioning of representation of 'the other'. In this context, an aesthetics of difference insists upon too, the questioning of images supporting hegemonic discourses, images which have filled the spaces in the 'chinks and cracks of the power/knowledge-apparati' (Teresa de Lauretis, 1987 cited in Pollock, 1999: 7-8). What would an 'eccentric rereading', a rediscovery of what the canon's vicarly cloak disguises and reveals, mean for music, and for the individual arts areas of the curriculum? I hope to reveal the entanglements of the cultural dynamics of power through an examination of the traditions of Truth and Beauty in imagery which are to be disrupted by inserting into the canon the principle of the aesthetics of difference. Art education as a politics of representation embraces art's constitutive role in ideology. This is to be exposed as we seek to unravel and acknowledge which kinds of knowledges are legitimised and privileged by which kinds of representations. Which kinds of narratives, historical or otherwise, have resulted in which kinds of depictions through image? A recognition of the increasing specification of the subject demands also the careful investigation of colonial representation, the construction of dubious narratives about our history created through visual imaging and its provision of complex historical references. How have art, music, dance, drama been used in the service of particular political and economic narratives? Through revisioning the curriculum from a postmodern perspective, suggestions are made for an alternative pedagogy, which offsets the ideological features of humanism/liberalism, one in which an aesthetics of difference might pervade cultural practices - 'systems of signification', 'practices of representation' (Rizvi, 1994). I draw upon Lyotard's notion of 'small narratives' (1984), and present an investigation of what the democratic manifestation of 'the differend', and multiple meaning systems, might indicate in terms of 'differencing' music education as a site in which heterogenous value systems and expression may find form.
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In materials science, the traditional methodological framework is the identification of the composition-processing-structure-property causal pathways that link hierarchical structure to properties. However, all the properties of materials can be derived ultimately from structure and bonding, and so the properties of a material are interrelated to varying degrees. The work presented in this thesis, employed artificial neural networks (ANNs) to explore the correlations of different material properties with several examples in different fields. Those including 1) to verify and quantify known correlations between physical parameters and solid solubility of alloy systems, which were first discovered by Hume-Rothery in the 1930s. 2) To explore unknown crossproperty correlations without investigating complicated structure-property relationships, which is exemplified by i) predicting structural stability of perovskites from bond-valence based tolerance factors tBV, and predicting formability of perovskites by using A-O and B-O bond distances; ii) correlating polarizability with other properties, such as first ionization potential, melting point, heat of vaporization and specific heat capacity. 3) In the process of discovering unanticipated relationships between combination of properties of materials, ANNs were also found to be useful for highlighting unusual data points in handbooks, tables and databases that deserve to have their veracity inspected. By applying this method, massive errors in handbooks were found, and a systematic, intelligent and potentially automatic method to detect errors in handbooks is thus developed. Through presenting these four distinct examples from three aspects of ANN capability, different ways that ANNs can contribute to progress in materials science has been explored. These approaches are novel and deserve to be pursued as part of the newer methodologies that are beginning to underpin material research.

With the introduction of personality research, occupational and job satisfaction research has advanced in scale. Evidence from studies within Personality Trait and Work Psychology research strongly suggests there to be connections between not only Neuroticism and job satisfaction rates, but that personality traits also seem to be unevenly distributed across occupations. This report sought to confirm and further explore findings made on Neuroticism and job satisfaction, as well as potential differences in personality traits among researchers in Social Science, Physical Science and Technology. Using the Five Factor Model (FFM) of personality and the Short Index of Job Satisfaction (SIJS), a survey study was conducted with a total of 83 participants. Using a Kruskal-Wallis test between fields of research and Personality Traits, this study found no significant differences between the fields of research. Correlations between Neuroticism and Job Satisfaction could not reach statistical significance enough to replicate previous findings. This report made other findings, such as significant links between personality traits, and discusses future research for this area of research.
Forskningen inom personlighetstyper innebar nya möjligheter för arbetspsykologin. Empiri ifrån studier föreslår starka kopplingar mellan jobbnöjdhet och personlighetstyper, men även att personlighetstyper skiljer sig mellan arbetsplatser och mer specifikt, mellan olika forskningsområden. Denna uppsats avsåg att hitta de kopplingar som gjorts tidigare mellan Neuroticism och jobbnöjdhet, men även eventuella skillnader i personlighetstyper mellan tre olika forskningsområden: Sociala vetenskaper, Fysiska vetenskaper och Teknologiska vetenskaper. Genom att kombinera Five Factor Model of personality (FFM) och Short Index of Job Satisfaction (SIJS) skapades två enkäter, en på Engelska och en på Svenska. Studien innehöll totalt 83 deltagare ifrån de tre valda forskningsområdena, och med hjälp av korrelationsberäkningar och Kruskal-Wallis test kunde man konstatera att resultaten som hade hittats av tidigare forskning inte kunde replikeras. Andra statistiskt signifikanta fynd mellan personlighetstyper gjordes dock, och dessa diskuteras tillsammans med implikationer för framtida forskning.

The analysis of presence/absence data of plant species by regression analysis is the subject of this thesis. A nonparametric approach is emphasized, and methods which take into account correlations between species are also considered. In particular, generalized additive models (GAMs) are used, and these are applied to species’ responses to greenhouse scenarios and to examine multispecies interactions. Parametric models are used to estimate optimal conditions for the presence of species and to test several niche theory hypotheses. An extension of GAMs called vector GAMs is proposed, and they provide a means for proposing nonparametric versions of the following models: multivariate regression, the proportional and nonproportional odds model, the multiple logistic regression model, and bivariate binary regression models such as bivariate probit model and the bivariate logistic model. Some theoretical properties of vector GAMs are deduced from those pertaining to ordinary GAMs, and its relationship with the generalized estimating equations (GEE) approach elucidated.
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Autonomous deterministic epidemiological models are known to be asymptotically stable. Asymptotic stability of these models contradicts observations. In this thesis we consider some factors which were suggested as able to destabilise the system. We consider discrete-time and continuous-time autonomous epidemiological models. We try to keep our models as simple as possible and investigate the impact of different factors on the system behaviour. Global methods of dynamical systems theory, especially the theory of bifurcations and the direct Lyapunov method are the main tools of our analysis. Lyapunov functions for a range of classical epidemiological models are introduced. The direct Lyapunov method allows us to establish their boundedness and asymptotic stability. It also helps investigate the impact of such factors as susceptibles' mortality, horizontal and vertical transmission and immunity failure on the global behaviour of the system. The Lyapunov functions appear to be useful for more complicated epidemiological models as well. The impact of mass vaccination on the system is also considered. The discrete-time model introduced here enables us to solve a practical problem-to estimate the rate of immunity failure for pertussis in New Zealand. It has been suggested by a number of authors that a non-linear dependence of disease transmission on the numbers of infectives and susceptibles can reverse the stability of the system. However it is shown in this thesis that under biologically plausible constraints the non-linear transmission is unable to destabilise the system. The main constraint is a condition that disease transmission must be a concave function with respect to the number of infectives. This result is valid for both the discrete-time and the continuous-time models. We also consider the impact of mortality associated with a disease. This factor has never before been considered systematically. We indicate mechanisms through which the disease-induced mortality can affect the system and show that the disease-induced mortality is a destabilising factor and is able to reverse the system stability. However the critical level of mortality which is necessary to reverse the system stability exceeds the mortality expectation for the majority of human infections. Nevertheless the disease-induced mortality is an important factor for understanding animal diseases. It appears that in the case of autonomous systems there is no single factor able to cause the recurrent outbreaks of epidemics of such magnitudes as have been observed. It is most likely that in reality they are caused by a combination of factors.
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This thesis examines the preparation and chemistry of osmium and ruthenium complexes with ligands featuring the group 14 donor atoms carbon and silicon, and the group l5 donor atom phosphorus. Aryl, alkenyl, and alkynyl complexes of osmium and ruthenium, prepared via mercury reagents, are discussed in Chapter One. 5-Coordinate 2-halophenyl complexes M(C6H4X-2)CI(CE)(PPh3)2 (M = Os; X = C1, Br; E = O, S; M = Os; X = I E = O; M = Ru; X = CI, Br, E = O) were synthesised by reaction of organomercury reagents Hg(C6H4X-2)2 (X = C1, I, Br) with MHC1(CO)(PPh3)3: (M = Os, Ru). Os(C6H4X-2)C1(CO)(PPh3)2 (M = Os; X = C1, I, Br) were characterised structurally and the interaction between X and M examined. Attempted benzyne syntheses using these complexes were not successful. 6-Coordinate complexes M(C6H4X-2)C1(CO)(CE)(PPh3)2 (M = Os, X = C1, E = O, S; Br, E = O, S; M = Os, E = O, X = I; M = Ru, E = O, X = C1, Br) were prepared by the addition of carbon monoxide to the corresponding 5-coordinate precursors. Approaches towards reduction of these complexes are discussed. The structure of Os(C6H4C1-2)C1(CS)(CO)(PPh3)2 revealed that the thiocarbonyl and the aryl halide ligands were cis and therefore in an ideal geometry to rearrange and form a substituted thioacyl ligand. Indeed, on heating Os(C6H4X-2)C1(CS)(CO)(PPh3)2 (X = C1, Br) the corresponding thioacyl complexes Os(η2-CS{C6H4X-2})C1(CO)(PPh3)2 (X = C1, Br) were formed. The decreased electron density in the halo aryl rings of these thioacyl complexes, combined with the fact that the halide substituents were no longer bonded to the metal, enabled facile lithiation of the aryl rings, even at low temperature. Quenching the appropriate lithiated intermediate with Bu3SnC1 gave Os(η2-CS{C6H4SnBu3-2})C1(CO)(PPh3)2. These results suggested that M(C6H4{CH2X}-2)C1(CO)(PPh3)2 (M = Os, Ru) were worthwhile target complexes for lithiation studies. To this end, Hg(C6H4{CH2OH}-2)C1 was prepared but attempts to convert the alcohol into a tosylate (for subsequent reaction with LiX) were unsuccessful and so this chemistry was not pursued further. Hg(C6H4{CH2OH}-2)C1 transferred the benzylic alcohol groups to osmium and ruthenium, albeit in low yields. Oxidation of Hg(C6H4{CH2OH}-2)C1 with PCC provided the benzaldehyde-containing mercury complex Hg(C6H4{CHO}-2)C1, symmetrization of which gave Hg(C6H4{CHO}-2)2. The latter compound was used to prepare aldehyde complexes of osmium and ruthenium, as well as mercury(II) benzaldoxime and benzaldimines. The aldehyde oxygen atoms in the osmium and ruthenium complexes were bound to the metals and were unaffected by amines, and by attempts to displace them from the metals. The addition of dimethyldithiocarbamate to Ru(C6H4{CHO}-2)C1(CO)(PPh3)2 displaced a triphenylphosphine ligand and Ru(C6H4{CHO}-2)(CO)({CH3}2NCS2)(PPh3) was formed. Transfer of the benzaldoxime ligand, and various benzaldimine ligands [C6H4{C[H]=NR] R = Me, CH2CH2NEt2, CH2CH2NMe2], to osmium or ruthenium gave M(C6H4{C[H]=NR}-2)C1(CO)(PPh3)2 (M = Ru, R = OH; M = Os, Ru; R = Me, CH2CH2NEt2;M= Ru, R = CH2CH2NMe2). The derived cationic complexes Ru(C6H4{C[H]=NCH2CH2NHR2}-2)C1(CO)(PPh3)2]BF4 (R - Me, Et) were prepared by protonation of the benzaldimine complexes with HBF4+ and Ru(C6H4{C[H]=NCH2CH2NR2}-2)(Co)(PPh3)2]BF4(R = Me, Et)were prepared by addition of AgBF4. Bromination of Ru(C6H4{C[H]=NMe}-2)C1(Co)(PPh3)2 gave Ru(C6H3{C[H]=NMe}-2, Br-4)C1(Co)(PPh3)2 which was lithiated at low temperature. The aryllithium was quenched with Bu3SnC1 to give Ru(C6H3 { C[H]=NMe}-2,SnBu3-4)C1(CO)(PPh3)2. The reaction of alkynylmercury reagents with osmium and ruthenium complexes are discussed in the following sections. Treatment of RuHCI(CO)(PPh3)2 with Hg(C≡CPh)2 has been reported previously, the result being formation of an α-phenylethynyl-trans-β-styryl ligand. However, the corresponding reaction with OsHCI(CO)(PPh3)3 resulted in catalysed coupling of the alkyne. This reaction was re-examined and the 6-coordinate α-phenylethynyl-trans-β-styryl osmium complex was prepared by direct reaction of the 5-coordinate complex with acetate ion. A dicarbonyl complex containing the α-phenylethynyl-trans-β-styryl ligand, Os(C{C≡Ph}=CHPh)CI(CO)2(PPh3)2, was prepared by the addition of carbon monoxide in the presence of LiC1 to the acetate complex. Thiocarbonyl complexes containing an α-phenylethynyl-trans-β-styryl ligand were prepared. Addition of carbon monoxide to solutions containing these complexes gave the thioacyl analogues M(η2-CS{C[C≡CPh]=CHPh})C1(CO)(PPh3)2 (M = Os, Ru). The remaining sections in Chapter One examine the reactions of mercury(II) reagents with the osmium(O) complexes Os(CO)2(PPh3)3 and OsCI(NO)(PPh3)3. Oxidative addition of the mercury-carbon bond of HgR2 (R = C6H4CH34, C≡CPh, trans-CH=CHPh) to Os(CO)2(PPh3)3 gave OsR(HgR)(CO)2(PPh3)2. Reaction of the acetylide or styryl complexes with iodine resulted in cleavage of the osmium-mercury bond and yielded either Os(C≡CPh)I(CO)2(PPh3)2 or Os(trans-CH=CHPh)I(CO)2(PPh3)2. Similar complexes were not accessible from reaction of the osmium(II) complex OsHC1(CO)(PPh3)3 with the appropriate mercury reagent. Whereas the mercury reagents reacted with Os(CO)2(PPh3)3 to give the simple oxidative addition products, the corresponding reactions of OsC1(NO)(PPh3)3 with HgR2 did not always give the analogous products OsR(HgR)C1(NO)(PPh3)2. Addition of Hg(C6H4CH3-4)2 to OsC1(NO)(PPh3)3 gave a mixture of the bis(p-tolyl) complex Os(C6H4CH3-4)2C1(NO)(PPh3)2 and the mono(p-tolyl) complex Os(C6H4CH3-4)CI2(NO)(PPh3)2. The structure of the bis(p-tolyl) complex revealed that the p-tolyl ligands were trans and the metal-carbon(aryl) bond lengths were extremely long. Addition of pyridine to the bis(p-tolyl) complex gave Os(C6H4CH3-4)2(C5H5N)CI(NO)(PPh3), which contained two cis p-tolyl ligands. The reactions of Hg(C6H4C1-2)2 and Hg(C≡CPh)Ph with OsCI(NO)(PPh3)3 gave complexes containing a single organic ligand. In contrast, treatment of OsCI(NO)(PPh3)3 with either Hg({C4H4S-2})2 or Hg([C4H4SMe-5]-2})2 gave the dithienyl complexes OsR2CI(NO)(PPh3)2 [R = (C4H4S)-2, ({C4H4SMe-5})-2. Furthermore, the reaction of Hg(CF3)2 with OsC1(NO)(PPh3)3 gave Os(CF3)(Hg{CF3})CI(NO)(PPh3)2. Treatment of OsCI(NO)(PPh3)3 with Hg(trans-CH=CHPh)2 gave Os(trans-CH=CHPh)CI2(NO)(PPh3)2 and an osmaindene complex, Os(C6H4CH=CH)H(NO)(PPh3)2, which in turn gave Os(C6H4CH=CH)Cl(No)(PPh3)2 on treatment with HCl. Chapter Two examines osmabenzene chemistry. Spectroscopic data were collected for the known complexes Os(η2-C[S]CH=CHCH=CH)(CO)(PPh3)2, and Os(C[SH]CH=CHCH=CH)(cis-CI)(CO)(PPh3)2. Oxidation of the osmabenzene thiol to a sulfinic acid was attempted. Methylation of the parent complex, Os(η2-C[S]CH=CHCH=CH)(CO)(PPh3)2, gave the product of kinetic control as Os(C[SMe]CH=CHCH=CH)(cis-I)(CO)(PPh3)2, reported previously, which rearranged on heating to give the trans isomer, Os(C[SMe]CH=CHCH=CH)(trans-I)(CO)(PPh3)2. Approaches to auration of the sulphur in Os(η2-C[S]CH=CHCH=CH)(CO)(PPh3)2, are described. Although the metallabenzenes reported previously have physical properties comparable with those of benzene itself, little evidence has been reported to suggest that the chemical reactivity of metallabenzenes is similar to that of benzene. The research described in this chapter provides the first example of a metallabenzene complex that undergoes aromatic electrophilic substitution. Thus, the metallabenzene complex Os(C[SMe]CH=CHCH=CH)(cis-I)(Co)(PPh3)2was brominated, chlorinated, and even iodinated. Crystal structure determinations and NMR studies showed that C5, which was activated by the thioether functionality, was the preferred site of electrophile attack. Even more significantly, Os(C[SMe]CH=CHCH=CH)(cis-I)(Co)(PPh3)2 was nitrated with either Cu(NO3)2/acetic anhydride, or with the more potent reagent NO2CF3SO3.CF3SO3H. The site of nitration was identical with that of halogenation, namely, C5. Previous syntheses of metallabenzenes had reported the use of the simplest alkyne, ethyne. This chapter describes the first metallabenzene complex prepared from propyne, giving the metallabenzene Os(η2-C[S]C{CH3}=CHCH=C{CH3})(CO)(PPh3)2 and the oxidative addition product Os(C≡CCH3)H(CO)(CS)(PPh3)2. Ten of the metallabenzene complexes were characterised structurally and the significance of the carbon-carbon bond lengths in the metallacyclic rings are discussed. The complete characterisation of these complexes by NMR spectroscopy revealed that the ring protons in the metallabenzene complexes, excepting H6, were at chemical shifts similar to those expected for normal aromatic carbons. Chapter Three examines the coordination of the strongly ח-accepting tris(N-pyrrolyl)phosphine ligand to osmium. Two tris(N-pyrrolyl)phosphine complexes of Os(II), OsHCI(CO)(PPh3)2(P{NC4H4}3) and OsH(C6H4CH3-4)(CO)(PPh3)2(P{NC4H4}3), were prepared. Both of these showed significantly higher infrared carbonyl stretching absorptions than the analogous triphenylphosphine complexes, reflecting the ח-acceptor nature of the tris(N-pyrrolyl)phosphine ligand. The osmium(O) complexes Os(CE)(CO)(PPh3)2P(NC4H4)3 (E = O, S) were prepared and the carbonyl complex was characterised structurally. The osmium-phosphorus(pyrrolyl) bond length of this complex was relatively short. The tris(N-pyrrolyl)phosphine ligand was in the equatorial plane as were the two carbonyl ligands. Chapter Four examines silyl and siloxane complexes of osmium and ruthenium. Although triethoxysilyl complexes of ruthenium have been prepared previously through ethanolysis of the coordinated SiCl3 group, the osmium analogues could not be prepared this way. It was found that Os(Si{OEt}3)CI(CO)(PPh3)2 could be prepared successfully by direct treatment of Os(Ph)Cl(CO)(PPh3)2 with triethoxysilane. Addition of carbon monoxide to the 5-coordinate triethoxysilyl complex afforded the dicarbonyl complex. The triethoxysilyl nitrosyl complex, OsH(Si{OEt}3)CI(NO)(PPh3)2, was prepared by oxidative addition of triethoxysilane to OsCI(NO)(PPh3)3, and the siloxane nitrosyl complex, Os(O[Si{OEt}3])CI2(NO)(PPh3 )2 was also characterised fully. Prior to this work only a single silatranyl complex was known. This chapter reports fifteen new silatranyl complexes and examines the unique properties conferred upon the silatrane by coordination to the metal. The silatranyl-containing complexes OsH(Si{OCH2CH2}3N)CI(No)(pph3)2 and OsH(Si{OCH2CH2}3N)(CO)2(pph3)2 were formed by oxidative addition of silatrane to the appropriate osmium(O) complex. Neither was suitable for further research because the chloro nitrosyl complex ejected silatrane in the presence of oxygen, and the dicarbonyl complex was isolated as a mixture of three isomers. In contrast, the unsaturated complexes M(Si{OCH2CH2}3N)C1(CO)(PPh3)2 (M = Os, Ru) were excellent materials for further study. The crystal structures of both of these complexes reveal typical metal-silyl distances with atypical silatranyl N→Si bond lengths. In both cases the N→Si bond length is elongated, the nitrogen is planar, and the cage is best described as quasi-silatranyl. The unsaturated nature of the metal in Os(Si{OCH2CH2}3N)CI(CO)(PPh3)2 offered access to derived complexes. The ח-acid carbon monoxide added to the vacant site forming Os(Si{OCH2CH2}3N)C1(co)2(pph3)2. Methylation of the 5-coordinate silatranyl complexes, gave [M(Si{OCH2CH2}3NMe)CI(CO)(PPh3)2]CF3SO3(M = Os, Ru). This reaction has not been achieved previously for silatrane derivatives. These methylated complexes have the longest recorded N→Si distances for any silatrane derivatives, and display a tetrahedral bridgehead nitrogen which points out of the cage at the methyl substituent. Protonation of the 5-coordinate silatranyl complexes gave [M(Si{OCH2CH2}3NH)CI(CO)(PPh3)2]CF3SO3 (M = Os, Ru). The thiocarbonyl-containing derivatives Os(Si{OCH2CH2}3N)CI(CS)(PPh3)2 and [Os(Si{OCH2CH2}3NMe)CI(CS)(PPh3)2]CF3S03 were prepared and these complexes showed spectroscopic properties similar to those observed for the carbonyl-containing analogues. The 5-coordinate silatranyl-thiocarbonyl complex rearranged in the presence of carbon monoxide to form Os(η2-C{S}Si{OCH2CH2}3N))CI(CO)(PPh3)2, which did not contain a metal-silicon bond. The silatranyl cage in the structure of this complex showed a very short N→Si bond with the nitrogen centre tetrahedral and pointing into the cage and towards the silicon atom. The osmium(IV) complex OsH3(Si{OCH2CH2}3N)(pph3)2 was prepared from OsH4(PPh3)2 and silatrane. The structure of this complex showed that the hydride ligands were oriented trans to a single triphenylphosphine in each case. Treatment of this complex with methyl iodide gave the quaternary salt [OsH3(Si{OCH2CH2}3NMe)(PPh3)3]I, and protonation gave [OsH3(Si{OCH2CH2}3NH)(PPh3)3]CF3SO3.

The synthesis of novel C9-halogenated anthracyclinones by Lewis acid promoted cyclisations of ortho-methallyl anthraquinonyl chiral dioxanes has been investigated. Tin tetrachloride-N,N-dimethylformamide promoted cyclisation of the dioxane (30) proceeded with excellent stereoselectivity to give an 82% yield of the diastereomerically pure chlorotetracycle (78). Stronger Lewis acids gave poorer selectivity and boron trifluoride etherate reacted slowly with (30) but with high selectivity to give the diastereomerically pure fluorotetracycle (91) in 58% yield. The presence of a β-methoxy group in the substrate leads to decreased stereoselectivity due to competition between chelation and non-chelation controlled pathways. Stereochemistry was assigned to the products using a combination of X-ray crystallography, conformational analysis, nuclear Overhauser enhancements and chemical degradation. Attempts were made to extend the highly selective acetal cyclisation methodology to the intramolecular reaction of the allylsilane (121), cyclisation of which was expected to provide enantioselective access to the alkene (146). The synthesis of (121) was achieved despite its instability, but attempted cyclisations with Lewis acids or fluoride ions were unsuccessful. The racemic alkene (146) was prepared by an ene cyclisation and subjected to asymmetric dihydroxylation (AD). The products from the AD reactions are of considerable biological interest and have been characterized. Their stereochemistry has been assigned by 1H nmr comparisons with the parent diphenols, which have resulted in revisions of assignments made by earlier workers.

Two amylin responsive proteins, here designated ARP1 and ARP2, were discovered from rat skeletal muscle through two dimensional gel electrophoresis analysis. ARP1 was detected only in amylin-stimulated muscles where the insulin-stimulated glucose incorporation into glycogen was inhibited. This protein incorporated 32Pi but not [35S]-methionine in the metabolic labeling experiments. Subsequent molecular characterisation revealed that ARP1 was a novel monomeric form (designated form 1) of protein p20, and two other monomeric forms (designated forms 2 and 3 respectively) of protein p20 were also characterised. The production of ARP1 was not affected by the presence of insulin, but calcitonin gene-related peptide (CGRP) was found to evoke the production of ARP1 in the presence or absence of insulin. In contrast, ARP2 was detected in both control and amylin-stimulated muscles. Amylin stimulation evoked incorporation of [35S]-methionine but not 32Pi into the protein and increased its concentration significantly. It is concluded that amylin elicits the production of ARP1 through phosphorylation and increases the protein biosynthesis of ARP2; the amylin-evoked production of ARP1 is insulin independent; amylin and CGRP share, at least in part, an intracellular signal transduction pathway; and ARP1 and 2 may be involved in the development of insulin resistance. It is suggested that ARP1 and 2 could potentially be used as molecular markers for the analysis of amylin action.

This thesis contains two parts. The first part describes the synthesis of orthogonally protected L-2,3-cis-3,4-trans-DHP 1.44 in eleven steps starting from L-arabinose via double displacement of bis-mesylate 2,8. The second part describes the synthesis of the spiroacetal fragment of the alkaloid broussonetine H. (±)-2-(3-Bromopropyl)-1,7-dioxaspiro[5.5]undecane (3.38) was prepared in nine steps from 1,4- butanediol (1.49), propargyl bromide (3.33) and δ-valerolactone (1.51). Enantioenriched material, namely (2S)-2-(3-bromopropyl)-1,7-dioxaspiro[5.5]undecane (4.2) was synthesized in thirteen steps from (2S)-pentane-1,2,5-triol (4.14), trimethylsilylacetylene (4.22) and δ-valerolactone (1.51). The enantiomeric excess of the derived alcohol, (4S)-3-(1,7-dioxaspiro[5.5]undec-2-yl)propan-l-ol (4.28) was measured by its conversion into a Mosher ester derivative 4.28. This thesis also describes the progress towards the synthesis of the dihydroxypyrrolidine fragment 5.28 of broussonetine H from L-sorbose (1.48).

The chemistry of transition metal silyl complexes still remains relatively undeveloped despite the recent advances that have been made in this area. This thesis describes the synthesis and reactivity of new ruthenium and osmium silyl complexes. A general survey on the bonding, preparation and reactivity of transition metal silyl complexes is given in chapter one as an introduction to the chemistry discussed in the following chapters. Several reviews relating to transition metal-silicon chemistry have been published, 1-5 and therefore only the major features and more recent developments are highlighted in this overview. Emphasis has been placed on those aspects not previously reviewed. Coordinatively unsaturated transition metal silyl complexes are uncommon and the chemistry of these complexes has been virtually unexplored. The synthesis of the novel coordinatively unsaturated ruthenium and osmium silyl complexes, M(SiR3)Cl(CO)(PPh3)2 (M=Ru, Os; R=Cl, alkyl group, alkoxy group), is described in chapter two. The reaction of M(Ph)Cl(CO)(PPh3)2 (M=Ru, Os) with a silane, in some instances, provided a facile, high yield route to complexes of the type M(SiR3)Cl(CO)(PPh3)2 (M=Ru; SiR3=SiMe3, SiEt3, SiCl3, SiMe2Cl; M=Os; SiR3=SiCl3, SiMe2Cl). The chlorosily1 complexes were also prepared by treatment of MHCl(CO)(PPh3)3 (M=Ru, Os) with HSiCl3 and HSiMe2Cl. X-ray crystal structures were obtained of Ru(SiEt3)Cl(CO)(PPh3)2 and Os(SiCl3)Cl(CO)(PPh3)2. Complexes containing chlorosily1 ligands proved synthetically useful, undergoing a variety of nucleophilic substitution reactions at silicon with retention of the transition metal-silicon bond. New complexes synthesized by this method included Ru[Si(OEt)3]Cl(CO)(PPh3)2 and Os(SiMe3)Cl(CO)(PPh3)2. X-ray crystal structures of these two compounds were also obtained. These exchange reactions illustrate a route to new transition metal silyl compounds that has rarely been utilised. Also described in chapter two is the unprecedented formation of the novel compound Os(SiMe2C6H4PPh2)(C6H4PPh2)(CO)(PPh3), resulting from phenylation at silicon. The structure of this complex was determined by X-ray crystallography. In chapter three, addition of the Lewis bases CO and CN(p-tolyl) to coordinatively unsaturated silyl complexes, M(SiR3)Cl(CO)(PPh3)2 (M=Ru, Os), is described. The coordinatively saturated osmium silyl complexes Os(SiR3)Cl(CO)L(PPh3)2 (SiR3=SiCl3, SiMe2Cl, SiMe2OEt, SiMe3; L=CO, CNR) were generated in this way. Similarly, addition of 4,4'-dimethyl-2,2'-bipyridine to Ru(SiEt3)Cl(CO)(PPh3)2 afforded Ru(siEt3)Cl(dimethylbipy)(CO)(PPh3). The six-coordinate complex Ru(SiEt3)(η2-S2CNMe2)(CO)(PPh3)2 was synthesized by displacement of the labile chloride ligand from Ru(SiEt3)Cl(CO)(PPh3)2 by the dimethyldithiocarbamate anion. Characterization of Ru(SiEt3)(η2-S2CNMe2)(CO)(PPh3)2 included an X-ray crystallographic analysis. The exchange of silyl groups at the metal was also observed in several reactions. For example, heating Ru(SiMe3)Cl(CO)(PPh3)2 in the presence of excess HSiEt3 yielded Ru(SiEt3)Cl(CO)(PPh3)2. These reactions illustrate aspects of the chemistry that can occur at the metal centre of coordinatively unsaturated transition metal silyl complexes. Another route to coordinatively saturated osmium silyl complexes was via oxidative addition of a silane to Os(CO)2(PPh3)3, which yielded Os(SiR3)H(CO)2(PPh3)2 (SiR3=SiMe3, SiEt3, SiPh3, SiPh2H). The synthesis of these complexes is also discussed in chapter three. An X-ray crystal structure determination of Os(SiEt3)H(CO)2(PPh3)2 confirmed the presence of mutually trans carbonyl ligands. The first thiocarbonyl-containing transition metal silyl complexes, M(SiMe2Cl)Cl(CS)(PPh3)2 (M=Ru, Os), were prepared by treating M(Ph)Cl(CS)(PPh3)2 or MHCl(CS)(PPh3)3 with HSiMe2Cl. The Si-Cl bond in these compounds reacted readily with nucleophiles, yielding M(SiMe2OR)Cl(CS)(PPh3)2 (OR=OEt, OMe, OH). In contrast to the addition of CO to Os(SiR3)Cl(CO)(PPh3)2, addition of CO to Ru(SiMe2R)Cl(CS)(PPh3)2 (R=Cl, OEt, OMe, OH) and to Os(SiMe2OEt)Cl(CS)(PPh3)2 afforded dihapto-thioacyl complexes, M[η2-C(S)SiMe2R]Cl(CO)(PPh3)2, via a migratory insertion reaction involving the silyl group and the thiocarbonyl ligand. This reaction represents the first formal insertion of CS into a transition metal-silicon bond. The structure of Ru[η2-C(S)SiMe2OEt]Cl(CO)(PPh3)2 was obtained by X-ray crystallography and confirmed that bonding of the thioacyl ligand occurred in a dihapto fashion. These reactions are described in chapter four. When Os(Ph)Cl(CO)(PPh3)2 was reacted with HSiMe3, the formally osmium(IV) silyl complex Os(SiMe3)H3(CO)(PPh3)2 was produced. Few compounds of this type are known. The synthesis, characterization and reactivity of Os(SiMe3)H3(CO)(PPh3)2 are discussed in chapter five. The crystal structure of Os(SiMe3)H3(CO)(PPh3)2 is also depicted. In solution, Os(SiMe3)H3(CO)(PPh3)2 appeared to be in equilibrium with the highly reactive, coordinatively unsaturated species OsH2(CO)(PPh3)2. The reaction of Os(SiMe3)H3(CO)(PPh3)2 with HSiR3 (R=Et, Ph), HSn(p-tolyl)3 and HC2Ph was carried out, using Os(SiMe3)H3(CO)(PPh3)2 as an in situ source of OsH2(CO)(PPh3)2. These reactions afforded Os(SiR3)H3(CO)(PPh3)2 (R=Et, Ph), Os[Sn(p-tolyl)3]2H2(CO)(PPh3)2 and OsH(C2Ph)(CO)(PPh3)3 respectively, most likely via a series of oxidative addition-reductive elimination reactions involving OsH2(CO)(PPh3)2. Transition metal hydroxysilyl complexes are extremely rare. Only three systems have been reported containing a hydroxysilyl group bonded to a transition metal. 6,7,8 Chapter six deals with the formation of compounds of this type. Hydroxysilyl-containing complexes of ruthenium and osmium were obtained via the hydrolysis of M(SiMe2Cl)Cl(CO)(PPh3)2 and M(SiCl3)Cl(CO)(PPh3)2. The complexes M[Si(OH)3]Cl(CO)(PPh3)2 are the first trihydroxysilyl-containing transition metal complexes and therefore represent a new class of transition metal silyl compounds. Characterization of Os[Si(OH)3]Cl(CO)(PPh3)2 included an X-ray crystal structure which showed that, remarkably, no inter- or intra-molecular hydrogen bonding of the type O(H)···O or O(H) ··Cl was associated with the Si(OH)3 group. In contrast, intermolecular hydrogen bonding was found by X-ray crystallography for the dicarbonyl derivative, Os[Si(OH)3]Cl(CO)2(PPh3)2. Subsequent reactions involving Os[Si(OH)3]Cl(CO)(PPh3)2 led to the synthesis of the diosmium tetrahydroxydisiloxane complex, [OsCl(CO)(PPh3)2Si(OH)2-]2O. For example, [OsCl(CO)(PPh3)2Si(OH)2-]2O was isolated after Os(SiCl3)Cl(CO)(PPh3)2 was added to a dichloromethane solution of Os[Si(OH)3]Cl(CO)(PPh3)2. Formation of this tetrahydroxydisiloxane compound is significant and models the first condensation reaction generating a Si-O-Si linkage in the hydrolysis of organochlorosilanes to polysiloxanes. The Si-O-Si linkage was clearly visible in the X-ray crystal structure of [OsCl(CO)(PPh3)2Si(OH)2-]2O. Chapter seven provides a short conclusion, highlighting the important features of the work discussed in this thesis and identifies areas for future investigation.

Light and atoms couple together via the electromagnetic interaction. The simplest form of this interaction is the electric dipole interaction, and in its quantised form it provides a useful starting point for the investigation of quantum effects in optics. Two examples of quantum noise manipulation of the light field due to interaction with atoms will be presented, as well as an analysis of a simple model for laser cooling of trapped atoms. The first example of quantum noise manipulation is the investigation of a quantum non-demolition measurement scheme based on a three-level atomic system in the ladder configuration. An effective two-level model of the atomic system is used, which enables the inclusion of spontaneous emission noise from the upper atomic level. The system is found to perform well, when detuned far from resonance. The second example is the treatment of squeezing in the intensity difference between two modes coupled by a three-level atomic system in the ladder configuration. The noise correlations are similar to those occurring in the optical parametric oscillator, and give rise to good squeezing when the system is well detuned from the intermediate level. The simple model of laser cooling consists of a single two-level atom with quantised centre-of-mass motion constrained to move in a one-dimensional harmonic potential while interacting with a single-mode classical travelling light field. It is shown that there is an analogy between this model and the Jaynes-Cummings model. This gives rise to interesting coherent effects including quantum collapses and revivals in the atomic inversion. Sideband cooling occurs for this model when the light field is tuned to the atom's first lower vibrational sideband. The strong sideband and Lamb-Dicke perturbation regimes are defined. Analytic results have previously been obtained for the latter regime, but we carry out a numerical investigation of the steady state and time evolution behaviour in the former regime. Differences in the behaviour in the two regimes are discussed. Finally the possibility of observing quantum jumps between trap levels is discussed.

This study attempts to develop the theory surrounding a controlled convergence theorem in the setting of AP integration. First, after a brief review, we spend some time on developing concepts and definitions. We are able to use these concepts to successfully present an initial control convergent theorem. Then we study our conditions more profoundly and find a number of equivalences and inequivalences between them. We are able to weaken some of the standard hypotheses significantly. The Riesz type approach to our integral has been included in our theory. Appropriately enough, we are able to use some of our approaches to extend the theory of the Henstock-Kurweil integral.

Reductively triggered internal cyclisation reactions have been investigated as a prodrug system for the hypoxia selective release of aromatic nitrogen mustards. The observed pseudo-first-order rate coefficients of cyclisation of several model 2-aminoaryl-acetamides and propanamides have been measured. Cyclisation was observed to be strongly influenced by stereochemistry, whereas electron withdrawal from the amine-bearing ring resulted in a comparatively modest slowing of the rate of cyclisation. Protonation of the leaving group appeared to increase the rate of cyclisation, while changes in 4-substitution on the leaving amine had little effect on this rate. The cyclisation of 2-(2-aminophenyl) alkanamides was found to be subject to general catalysis by acidic buffer components, and rate determining formation of the tetrahedral intermediate has been proposed. Ring closure reactions of several 2-hydroxylaminophenylalkanamides have been studied by γ-radiolysis. HPLC methods have been developed for the separation of reduction and cyclisation products. Reduction stoichiometry implicates the hydroxylamine as the predominant reduction product of radiolysis of the 2-nitrophenylalkanamide precursors, which varied in the nature of substitution of the nitrobenzyl ring, 4-substitution of the leaving aniline, and overall geometry. Cyclisation via the hydroxylamino was observed to be significantly faster than that of its amino counterparts, and was similarly influenced by changes in geometry. The hydroxylamine undergoes a base catalysed, oxygen dependent reaction under aerobic conditions. This reaction did not appear to be influenced by the geometry of the compound. Substitution of the hydroxylamine-bearing ring with a carboxamide group (CONHR σp = 0.36) lowered the pH at which hydroxylamino-amide cyclisation was slowest, compared with its unsubstituted counterpart. The reaction was found to be aided by electron-withdrawal from the leaving amine. Rate determining breakdown of the tetrahedral intermediate has been proposed. Preliminary investigations have been made on 2-nitrophenyl alkyl esters and a 2,6-dinitrophenylamide prodrug system. Rapid, reductively triggered release of coupled phenols and amines has been observed from the nitro-esters and -amides, respectively. In contrast to amino-amide and hydroxylamino-amide cyclisation, gem-dimethyl substitution did not facilitate reductive release from the nitro-ester. The inability to measure the rates of reductive release in radiolysis solutions suggests that these reactions occur significantly faster than hydroxylamino-amide ring closure. Molecular mechanics calculations have been undertaken to investigate relationships between the geometry of 2-aminoarylalkanamides, and rates of cyclisation. The distance between, and angle of approach of the nucleophilic and electrophilic centres in the calculated minimum-energy conformer did not display a correlation with cyclisation rates.
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This thesis is concerned with the generation of picosecond pulses and their propagation through both resonant and non-resonant media. This was achieved by constructing a passively modelocked Erbium doped fibre laser (EDFL) which was used to study pulse propagation through sections of standard communications grade optical fibre, dispersion shifted optical fibre, and also through an Erbium doped fibre amplifier (EDFA) module. The EDFL produced a train of ˜2 psec pulses at 4 MHz, tunable over the erbium gain band ( 1520 - 1570 nm). The laser was constructed from commercially available components and had the property of stability combined with low pump power requirements to produce ˜50 Watt peak power pulses. The laser cavity geometry included a nonlinear optical loop mirror, which has the property of efficiently switching high peak power pulses, and allowed pulsed operation without the aid of any high-speed electronics. An EDFA module of identical geometry to that used in the laser was also constructed, and this was probed using the pulses from the EDFL. The traditional temporal and spectral measurements were found to be inadequate to allow a complete description of the pulse amplification process to be developed. To overcome this problem the technique of frequency resolved optical gating (FROG) was applied for the first time to optical fibre research, and allowed an indirect measurement of the electric field of the pulse. This complete description of the pulse was used in a numerical model to describe pulse propagation in an optical fibre. Fundamental propagation terms in the model were treated as free parameters in a minimisation scheme, which could be determined for a fibre under examination. This technique was shown to be accurate when used to examine pulse propagation through both standard and dispersion shifted optical fibre. A comprehensive numerical model was developed for the EDFA, and it was apparent from this model that a pulse propagating through an optimised EDFA encounters an atomic inversion distribution which is a strong function of distance along the amplifying fibre. It was also shown from the experimental results that the EDFA exhibited resonant dispersion, which is characteristic for propagation through an atomic medium on resonance.

The Claisen rearrangement of 1,4-bis(prop-2'-enyloxy)anthraquinone under reducing conditions is investigated. The elaboration of the product of double Claisen rearrangement towards an anthracyclinone skeleton is reported. The insertion of methyl ketone and aldehyde functions into the C-2 and C-3 positions of the anthraquinone skeleton and the subsequent elaboration towards an anthracyclinone skeleton is investigated. Methods for the conversion of hydroxymethylanthraquinones to side chains suitable for anthracyclinone syntheses are reported. A total synthesis of 7,9-didesoxydaunomycinone from 1,4-dihydroxy-2-methylanthraquinone is described.

Chapter one of this thesis reports an investigation of the synthesis of potential amber odorants from abietic acid. The acid catalysed rearrangement of abietic acid afforded two isomeric dienes the structures of which have been elucidated. Compounds containing the diene functionality were found to be unstable. However, removal of the diene system afforded stable compounds which are suited to further synthetic modification. Although the skeletal features possessed by a class of amber odorants were successfully introduced stereochemical control proved difficult. The stereochemistry of two intermediates was unambiguosly assigned by single-crystal X-ray diffraction experiments. The second chapter describes the successful conversion of totarol into conjugated dienolides possessing the B/C-ring present in type A and type C nagilactones. Consequently totarol may be considered as a useful model for the preparation of the biologically active nagilactones. In the course of this work several unusual rearrangements were observed. The products of rearrangement were characterised by 2-D n.m.r. and single crystal X-ray diffraction experiments and reaction mechanisms are proposed. The third chapter of this thesis reports the synthesis of the amber odorant, γ-bicyclohomofarnesal, from podocarpic acid. Analogues in which C-19 is functionalised were also prepared. However these compounds were odorless.

Carbon monoxide adsorption, surface speciation and particle size distributions have been studied in platinum, palladium, and rhodium hydrosol systems using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. In transmission electron micrographs of unprotected platinum and palladium hydrosols, particle necklacing believed to arise from sintering during preparation, is apparent. The average particle sizes of all hydrosols studied were in the range of 2 to 12 nm. X-ray photoelectron spectra of the metal hydrosols revealed evidence for (Pt-O)ads, Pt(II) and Pt(IV) oxides on platinum hydrosol particles whereas Pd(II) and Pd(IV) oxides were detected on the surfaces of palladium hydrosol particles. These surface oxides are found to be important in influencing hydrosol surface processes such as CO adsorption as a function of pH, inhibition of CO adsorption by alcohols and surface corrosion products resulting from the addition of iodide and cyanide. Fourier transform infrared spectra of CO-treated metal hydrosols revealed bands due to CO linearly adsorbed on the metal particles at ca. 2070 cm-1 (Pt), 2067 cm-1 (Pd) and 2045 cm-1 (Rh) whereas bands due to bridge-adsorbed (B2) CO were detected at ca.1950 cm-1 (Pd) and 1890 cm-1 (Rh). The use of CO as a spectroscopic probe molecule enabled the study of changes in the surface properties of the metal hydrosols which were induced by changes in the dispersion medium. For example, v(CO)ads was observed to decrease in infrared spectra of CO-treated platinum and rhodium hydrosols as pH was increased by KOH or other dissolved salts yielding alkaline solutions. This suggested a reduction in CO coverage resulting from hydroxyl adsorption and consequent increased oxide growth on the particles. In contrast, CO adsorption on platinum and rhodium hydrosols was enhanced in acidic media possibly as a result of the neutralisation of surface hydroxyls. The spectroscopic behaviour of adsorbed CO on platinum and rhodium hydrosols was only comparable to that of CO adsorbed at an electrode surface in acidic media when protecting agent was present which prevented aggregation of the hydrosol in such media. Inhibition of CO adsorption on platinum hydrosols was induced by the addition of aliphatic alcohols, poly(vinyl alcohol) and poisoning anions such as CN- and SH-. Correlations of v(CO)ads with CO coverage suggested that island formation of adsorbed CO was occurring for CO adsorption on unprotected palladium hydrosols and protected platinum and rhodium hydrosols as a function of pH. In allied investigations, an infrared spectroelectrochemical study of corrosion of a nickel electrode in aqueous cyanide media has revealed that [Ni(CN)4]2- is detected at potentials more cathodic than 200 mV vs. SCE. Cyanide was oxidised to cyanate (OCN-) and then successively to carbon dioxide at potentials more anodic than 200 mV vs. SCE. The appearance of features at 2094 cm-1 (HCN) and 2256 cm-1 (HNCO) were attributed to pH changes associated with the oxidation of cyanide to cyanate. The appearance of a band at ca. 2218 cm-1 in infrared spectra of the thin layer at very high potentials (> 1000 mV vs. SCE) was believed to arise from an unstable nickel(II) isocyanate complex.

An investigation has been carried out into the operation of a mode-locked argon laser at a wavelength of 514.5 nm and a repetition rate of 76.8 MHz. The characteristics of the pulses from the laser have been found to depend on the intra-cavity power level in the laser, and at average intra-cavity power levels exceeding 4 W, the pulses from the laser have a duration of typically 35 psec accompanied by a characteristic double-peaked spectrum with a spectral width of 13 GHz These pulse durations are approximately three times shorter than expected based on the inhomogeneously broadened transition bandwidth of 4 GHz. The dependence of the pulse characteristics on the intra-cavity power level has been explained by a model of pulse propagation where the coherent coupling between the pulse and the atomic polarisation in the laser gain medium is included. Detailed examination of the pulse structure reveals the presence of afterpulses that have a typical intensity two orders of magnitude lower than the main pulse. These afterpulses are interpreted as ringing arising from coherent Rabi-type oscillation of the atomic polarisation associated with the circulating pulse in the laser. Numerical simulations of the mode-locked laser have also been developed based on the fully coherent Maxwell-Bloch equations, and the results from the simulations reproduce well the experimentally observed variation in pulse characteristics. Based on results from the simulations, the short pulses observed at high intra-cavity powers are interpreted as the superfluorescent π –pulse solutions predicted in the long distant limit of pulse propagation in a swept-gain amplifying medium. The laser operation has also been studied in a mode-locked cavity dumped configuration. In this case the combination of the coherent mode-locking processes described above with the cavity dumped operation at a repetition rate of 3.8 MHz results in the observation of stable pulses with peak power of 1.6 kW.

Chapter One of this Thesis reports an investigation of the synthesis of diterpenoids (as potential ligands for cyclomanganation reactions) from podocarpic acid, and one from dehydroabietic acid. A number of monocyclic aromatic and chalcone derivatives were synthesised to act as model compounds in the subsequent complexation reactions. The second chapter describes successful complexations of the above ligands containing aldehyde, ketone, ester, or oxime groups as directing functionalities to form the resulting tetracarbonylmanganese sigma adducts in moderate to excellent yield. Attempted complexation of amide-containing ligands proved generally to be unsuccessful. Complexation of ligands containing either two potential sites for manganation or two potential ligating groups were investigated and the structures of the isolated complexes established unequivocally by N.M.R. spectroscopy or by X-ray crystallography. Chapter Three describes the successful coupling reactions of the tetracarbonylmanganese complexes with ethene and with substituted electron-poor olefins to give pentaannulated derivatives of podocarpic acid in very good yields. The stereochemistry of two cyclised alcohols was assigned unambiguously by single-crystal X-ray diffraction experiments. Various methods of activating the tetracarbonyl complexes were investigated, including chemical oxidation, and palladium(II)-mediated or thermally-promoted reactions. Two of the pentaannulated adducts were converted successfully into benzannulated analogues in good yield. Analogous coupling reactions of the activated complexes with ethyne and substituted alkynes are discussed in Chapter Four. Chapter Five reports an investigation of the reactions of the tetracarbonylmanganese complexes with halogen electrophiles such as Br2, ICl, or ICl3. When these reactions were performed in non-protic solvents the corresponding aryl halides were isolated in moderate to excellent yield. However, in protic solvents carbonyl insertion occurred to afford γ-lactones in very good yield. The stereochemistry of one of these lactones was assigned unambiguously by a single-crystal X-ray diffraction experiment. Oxidative cleavage of the C-Mn bond with a number of reagents proved generally to be unsuccessful, the isolation of oxygenated diterpenoids being observed only from reaction with Pb(OAc)4. Chapter Six describes various attempts at functionalising ring C of podocarpic acid derivatives via alternative methods to cyclomanganation. These include an investigation into the formation of η4-dienol ether and η4-diene tricarbonyliron complexes derived from the Birch reduction products of podocarpic acid derivatives; attempted regioselective chlorination and mercuration studies of ring C arenes; functionalisation of chlorinated podocarpic acid derivatives via their tricarbonylchromium complexes; and attempted oxidation of ring C arenes with meta-chloroperbenzoic acid.

The synthesis and ozonolysis of the 6- and 7-substituted 12-hydroxypodocarpatrienes (26), (86), (90), and (98), as a possible route for the synthesis of drimanes from 12-hydroxypodocarpa-8,11,13-trien-19-oic acid (podocarpic acid) (9) has been investigated. Modification of the aromatic ring of (9) has given 11- and l4-hydroxypodocarpatrienes which were ozonised to give the congeners (31), (34), and (36) of the naturally occurring drimanes confertifolin (6), isodrimenin (7), and winterin (8). The oxidation of a 12,13-dihydroxypodocarpatriene (37) and its dimethyl ether (38) have also been investigated. Routes for the conversion of the enone (45) and oxime (230), derived from the ozonolysis products of methyl podocarpate (10), to drimanes have also been investigated.

Primary and secondary amines react with pentachlorocyclopropane to form a variety of novel products. Amidines, allyl and cyclopropenyl cations are easily reached by these reactions. The 1,1,3,3-tetra-aminoallyl cations of this series can be reversibly protonated at C(2) to give diamidinium ions. Action of KOH on the diamidinium species CH2[C(NHBut)2]2 2+ produces the diamidine CH2[C(NBut)(NHBut)]2 which hydrolyses to the formamidine CH(NBut)(NHBut). Bis- and tris-amino substituted Cyclopropenylium ions are formed by the action of secondary amines on pentachlorocyclopropane. The cations of this study are stabilised by electron back-donation from nitrogen atoms of substituent groups- The subject of back-bonding was probed in several ways. crystallographically determined structures of representative salts afforded bond length data from which deductions about back-bonding were made. The measurement of barriers to bond rotation is another way that this effect was investigated. Using the technique of variable temperatue NMR, VT-NMR, spectroscopy, energies of activation about unsaturated bonds of allyl, amidinium and cyclopropenylium cations were found. UV-spectra provided additional information concerning bonding in these species. Tautomerism of N,N’-disubstituted amidines was investigated by VT-NMR spectroscopy. Individual tautomers were identified in NMR spectra (13C,1H). Tris-alkylaminocyclopropenylium ions were oxidised to form intensely coloured radical dications. The first Raman spectrum of a cyclopropenyl radical dication was determined. Using the technique of pulse radiolysis we were able to reduce the cyclopropenylium cation, [C3(Net2)3]+, to the molecular radical. Further, pulse experiments enabled standard reduction potentials of representative [C3(NR2)3]2+ and allyl radical dications to be measured and compared. In general, tertiary amines reacted with pentachlorocyclopropane to generate product mixtures. Reaction of para-dimethylaminopyridine, DMAP, on pentachlorocyclopropane was a case in exception. The novel allylide product is the same as that formed via an alternative route. The direct reaction of ammonia on pentachlorocyclopropane product several products including the formamidine NC-N=CH-NH2. A polyamide was prepared from the hydrolysis of a diamidinium ion. The mechanism of formation and the characterisation of this glossy, thermoplastic material is discussed.

Sulfate removal from sulfomucin is believed to be a rate-limiting step in sulfomucin degradation by bacteria from the digestive tract. A novel sulfomucin-desulfating enzyme has been discovered in the anaerobic bacterium, Prevotella strain RS2, which can grow on colonic mucin as its sole energy source. The enzyme, located in the periplasm, was assayed by measuring p-nitrophenol removal from the model substrate sulfate-6-N-acetylglucosamine-1-p-nitrophenol, sulfate-6-N-acetylglucosamine being the other product. This activity differs from that of sulfatases which remove the sulfate ester group from sulfate-6-N-acetylglucosamine and its analogues substituted at the Cl position. The enzyme has been termed a sulfate-6-N-acetylglucosaminidase or sulfoglycosidase (SGL). The SGL was purified to a single protein band of 100 kDa as analyzed by SDS-PAGE. The purified SGL protein was trypsin-digested and peptide fragments were sequenced. PCR and inverse PCR were then used to amplify the entire sg/ gene from Prevotella strain RS2 genomic DNA. After inserting the gene into a suitable plasmid, active recombinant SGL was expressed using an Escherichia coli expression system. The SGL was characterized using a selection of model substrates, and shown to be an exo-enzyme that removes non-reducing terminal sulfate-6-N-acetylglucosamine residues by glycosidic bond cleavage. When tested against its putative physiological substrate, sulfomucin, the only small molecular size product detected corresponded to a sulfate-6-N-acetylglucosamine residue. Thus the SGL can catalyze a reaction, formerly thought to be performed in bacteria by the combined actions of a N-acetylglucosamine-6-sulfatase and a N-acetylglucosaminidase. Inhibition studies on the SGL were carried out. Inhibitors of the SGL and those of the sulfatases were used to confirm the presence or absence of SGL-like activity in other bacteria that inhabit environments containing sulfomucin. Four isolates, including Prevotella strain RS2, of the thirteen strains tested, appeared to have SGL-like activity. This research on the SGL with its novel catalytic activity, suggests a new mechanism by which sulfomucin desulfation can occur. The physiological importance of the enzyme is postulated to be (i) to provide energy in the form of sulfate-6-N-acetylglucosamine, for the bacterium, (ii) to remove sulfate-6-N-acetylglucosamine groups present on mucin chains, thus creating or removing sites for different adhesins, and (iii) removal of inhibitory sulfate-6-N-acetylglucosamine groups from mucin chains that limit degradation of the chain by exoglycosidases and neuraminidases.

Copolymerisation of ethyl cellulose (EC) with methyl methacrylate (MMA) and vinyl acetate was carried out in solution, using a number of free radical initiators, to form graft copolymers with grafting yields up to 63% and weight average molecular weight about 9 x 104 g mol-1 Graft copolymerisation of MMA and EC appears to involve participation of comonomer charge transfer complexes at the initial stage of reaction, Interaction of EC with the carbonyl group of MMA enhances the electron-accepting ability of EC and promotes the formation of a donor-acceptor complex as matrix, with the resultant generation of a covalent bonded monomer radical, which then propagates in the usual manner to produce EC-g-PMMA. The influence of a number of experimental variables on the grafting efficiency of the EC-g-PMMA reaction, and the properties of the resulting copolymers, was investigated. The initiator has a significant effect on the grafting efficiency, which decreases in the order azobisisobutyronitril>ammonium persulphate>potassium persulphate>Ce(IV) ion. Benzoyl peroxide was found to be unsuitable because it promoted degradation of ethyl cellulose chains. The order of solvent influence on the grafting yield is chloroform>toluene>benzene. The grafting yield is also reaction time and temperature dependent. A2-3 hour reaction time and 40-50°C reaction temperature gives a substantial increase in both reaction rate and the molecular weight of the graft copolymer product. The introduction of PMMA graft side chains onto EC main chains leads to a significant decrease in the radius of gyration in solution, as determined by size exclusion chromatography, compared to linear EC. This finding is explained by the theory of Stockmayer and Fixman in terms of the number and type of long chain graft points in the molecule, Calculation of viscosity of EC-g-PMMA in solution using the Kurata equation gave values in good agreement with the experimentally determined viscosity. A significant result is that grafting PMMA branches onto EC reduces the hydrodynamic volume, and differential scanning calorimetry showed conclusively that increasing PMMA sidechain length reduces the chain flexibility, by reduction of free volume. The glass transition temperature of EC-g-PMMA, produced by using a large excess of MMA monomer and reasonably long reaction time, was shifted to higher temperature with increase of grafting yield and molecular weight. A single glass transition is observed for copolymers made using low initiator concentrations, and two glass transitions are found for higher initiator concentrations. In addition, EC-g-PMMA samples with higher grafting yield are more brittle than those with lower grafting yield. However, both the bending modulus (determined by dynamic mechanical thermal analysis) and elongation at break increase with grafting yield. Our experiments proved that the crystallinity of EC-g-PMMA is less than that of pure EC and greater than that of pure amorphous PMMA. The specific oxygen gas-permeability coefficients of EC-g-PMMA films decrease with increase of grafting yield. The reason is that grafting decreases of hydrodynamic volume. Interestingly, X-ray diffraction showed that the higher the grafting yields of EC-g-PMMA, the higher its crystallinity. Films of EC-blend-PMMA, made by solution casting and examined in cross section using scanning electron microscopy, showed an essentially multiple layer morphology with non-uniform dispersion of PMMA in the EC matrix. Scanning electron microscopy confirmed, as expected, that EC-g-PMMA cast films were homogeneous with no evidence of phase separation. The tensile strength of EC-g-PMMA films was typically about 20% higher than that of EC-blend-PMMA films, and the graft copolymer films exhibited greater oxygen permeability. A new model for graft copolymerisation to EC is proposed. The model provides for the possibility that grafting to EC with 48% ethoxy content can occur at the five OC2H5 groups and one OH group per unit. It was established using NMR spectrometry of EC-g-PMMA and EC-g-Poly (vinyl acetate) that under some conditions the ethoxy groups are the favoured graft sites. The liquid crystalline properties of EC and EC-g-PMMA were extensively investigated. Optical microscopy with crossed polarisers revealed that the relatively short mesomorphic temperature range of ethyl cellulose is extended downwards almost to ambient temperature in the graft copolymer. Low frequency Raman scattering showed that EC-g-PMMA has higher light scattering intensity than EC at ambient temperature. But it was lower than that of EC at 191°C. Moreover, the Jaynes-Cummings model cannot predict the light scattering intensity of EC-g-PMMA as a function of frequency very well, whereas the EIT-Kerr scheme is able to successfully account for the experimental observations. It was found that EC and EC-g-PMMA are pseudoplastic, lyotropic and thermotropic materials whose viscosity in solution is dependent on many factors, particularly on temperature and solution concentration. Both materials show unusual rheological behaviour, including maxima in the isothermal concentration dependence of viscosity. Unmodified EC exhibits thixotropic flow behaviour, whereas grafting PMMA side chains onto EC changes the flow behaviour to rheopectic, which is also typical of PMMA itself. As the temperature and concentration increase, the viscosity increases in response to the transition from an isotropic to an anisotropic state of EC-g-PMMA. Furthermore, experiments on the distinguishing characteristics of EC-g-PMMA indicate that different solvents affect its anisotropic flow behaviour to a greater or lesser extent. In particular, chloroform shows a stronger flow orientation effect than tetrachloroethane on EC-g-PMMA solutions. The rheological behaviour of EC and EC-g-PMMA in the nematic phase is much more complex than that of ordinary polymers or low molecular weight liquid crystals. The Doi theory is usually applicable to ordinary polymers or low molecular weight liquid crystals, but cannot predict shear stress as a function of shear rate; particularly at very low shear rates for EC and EC-g-PMMA. Whereas, the polydomain model is better to account for the observations. Measurements of thermally stimulated depolarisation current showed that EC-g-PMMA has a longer dipolar relaxation time in an electrical field. Molecular dipole motions of EC give a maximum depolarisation current at 138 °C in the glass transition region and another maximum near 200 °C, corresponding to dipolar relaxation in the liquid crystalline phase. EC-g-PMMA shows a broader dipolar relaxation temperature range in the liquid crystalline phase and the depolarisation current maximum shifts to a lower temperature. We have observed that field induced polarisation of EC-g-PMMA is affected by the length of the PMMA side chain, and obeys an interfacial model of the Maxwell-Wagner-Sillars type. It was confirmed by X-ray photoelectron spectroscopy that the length of the PMMA side chain could affect the surface properties. EC-g-PMMA has higher photoemission intensity than EC, and the photoemission intensity and depolarisation current increase with grafting yield.

High current anodization of magnesium and magnesium alloys Ellen Angharad Carter Pure magnesium and three magnesium alloys containing different amounts of aluminium (2-9%) plus zinc and manganese were anodized with constant current density in sodium hydroxide solution with and without fluoride or phosphate ions. Electric field strengths of resultant anodic films were calculated from galvanostatic transients. These transients showed three characteristic features: linear voltage increase, noisy high voltage signals accompanied by sparking, and sawtooth-like events characterized by instantaneous voltage drops followed by slower voltage increases. Each feature was linked to certain physical processes occurring in the metal/film/solution system. Oxidation of magnesium and magnesium alloys formed anodic films with bilayer structures: a passive barrier layer adhering to the metal electrode, topped by a porous secondary layer. Cation injection into the barrier film across the metal/oxide interface was the rate determining step for film growth. Interstitial cations migrated through the film under the influence of the electric field. At the film/solution interface they reacted with electrolyte species and either thickened the film or dissolved in solution. Electric field strength was constant for particular metal/solution combinations and was independent of applied current density. Changing the electrode material altered the resultant electric field strength: pure magnesium produced oxides with lower electric field strengths than films formed on the three magnesium alloys. Changing the electrolyte had no discernable effect on the electric field strength. Charge efficiency of the film growth process was investigated by oxygen gas evolution; efficiency decreased during sparking. Ion beam analysis (Rutherford backscattering, fluorine depth profiling and nuclear reaction analysis) coupled with X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray diffraction studies and Raman spectroscopy gave information about the anodic film surface. These techniques showed that oxides formed on magnesium-aluminium alloys were thinner than those formed on pure magnesium caused by aluminium dissolution. Fluorine depth profiling revealed that concentration profiles for fluorine in anodic oxides formed in fluoride-containing solution altered depending on the aluminium content of the electrode material.

A range of compounds related to the diquaternised salts of 2,2'-dtpyridine and 4,4'-dipyridine was studied in the present investigation. The effect of the change in the redox-state of the compounds was determined by vibrational spectroscopic and molecular orbital techniques. The investigation of 2,7-dimethylthieno[2,3-c:5,4-c'] dipyridinium diiodide monohydrate was undertaken by X-ray diffraction, vibrational spectroscopic and molecular-orbital techniques. These investigations showed that the thiophenic portion of the dication exhibited partial aromaticity. On formation of the radical monocation, a pattern of bond length changes consistent with the formation of a quinoidal structure was predicted by molecular-orbital calculations. This suggests that the electron delocalisation occurs over the entire molecule. The resonance Raman spectrum of the cation monoradical exhibits bands which may be assigned to the thiophenic portion, which suggests that this portion is associated with the chromophore. IR spectroscopic investigations into the electrogenerated radical of N,N'-diheptyl 4,4' - pyridinium, which has been investigated as the coloured component of electrochromic displays, were performed. The reflectance IR spectra of the radical monocations were obtained through bulk-sampling potential subtraction (PS) and surface-selective polarisation modulation (PM) techniques. The comparison between PS and PM spectra of the radical generated as a solid film in an aqueous medium, with the PS spectrum of the radical generated in acetonitrile revealed differences. These were interpreted in terms of an equilibrium between monomeric and aggregated forms of the radical. Similar results were obtained for the related compounds, methyl viologen and its dicyano substituted salt. The simplicity in the pattern of bands in the PS IR spectra of the monomeric radicals of methyl- and dicyanomethyl viologens was investigated by calculating the IR spectra of the dications and cation radicals of these compounds by molecular orbital techniques. The intense spectral features could be interpreted in terms of a charge-oscillation of the radical electron across the pyridine rings. The dipole moment of such modes is large and leads to the enhancement of these modes. The effect of various counterions associated with heptyl viologen was investigated by Raman and IR techniques. The pattern of bands in the Raman spectrum exhibited little variation with differing the counterions. The PS IR spectra exhibited disappearance features associated with the counterion in contrast to the PM spectra where no such bands were observed. PS IR spectra were also obtained by synchronising data acquisition with potential sweeps. The intensity of disappearance features in the PS IR spectra attributable to the CH modes varied at a similar rats to bands assigned to the radical aggregate. This suggested that a reorientation of the dipyridine ring and the quaternising alkyl chain probably occurs on reduction to form the radical. The lack of reversibility associated with the degradation of viologen films was investigated by PS IR techniques. The effect is probably associated with changes in the composition of the solid rather than a change in the concentrations of the monomeric and aggregated forms of the viologen radical. Dialkyl bridged diquaternary compounds of 2,2'-dipyridine were investigated by IR and theoretical techniques. The observation that the calculated dihedral angles for the dications and cation radicals were similar allowed the trends in the electronic absorption maxima (ultra-violet) and electrode potentials to be interpreted. Selective enhancements of bands in the PS IR spectra of the radicals suggest that a charge-oscillation mechanism may also be operative in these compounds. The utility of a combination of structural, theoretical and vibrational spectroscopic studies is demonstrated in these studies.

Chapter One begins with an introduction to enzymology and leads into a discussion on BSSL beginning with the physical properties and the source of the enzyme. The literature concerning the kinetic properties of BSSL is reviewed, followed by a discussion on how the structure of enzymes influences their catalytic activity and specificity. The use of X-ray crystallographic techniques is addressed as a means of elucidating the three dimensional structure of enzymes. The chemicals, apparatus and standard methodologies used in this present investigation are described in Chapter Two. The means by which kinetic data measured for an enzyme-substrate system are analysed and compared are also discussed. Chapter Three describes the purification of bile salt-stimulated human milk lipase (BSSL) from whole human milk. A detailed study of the activity of the purified protein has been conducted against both lipid and ester substrates in order to monitor the progress of the purification. A further determination of the physical properties of the protein has also been conducted. Results from these studies have identified the protein as BSSL. In Chapter Four the methods used for determining the partial amino acid sequence of the enzyme are described. This study has revealed interesting homologies with enzymes from other species. The sequence of that part of the enzyme which includes the active site has been determined and has been found to be identical to the consensus sequence found in the active site of pancreatic lipase, serine proteases and cholinesterases. It may therefore be postulated that the similarity observed for some of the kinetic behaviour of enzymes arises from homology in their amino acid sequences and, in particular, those portions of the protein comprising the active site. The use of kinetic isotope effects, to gain insight as to the mechanism of BSSL catalysed hydrolysis of lipid substrates, is the subject of Chapter Five. A mechanism has been proposed which explains the observed effects and takes into account information from the literature. The mechanism also incorporates findings made from the amino acid sequence study and the literature reports on the residues involved in catalysis. Chapter Six begins within a literature survey of detergent less microemulsions and continues with an account of the kinetic properties of BSSL in this new and novel medium in which enzymic reactions involving substrates of low water solubility may be conducted. The advantage of this medium is that it allows one to monitor the reaction by spectrophotometric means. In more traditional methods of assay of lipid substrates this is not normally possible. This advantage has also been exploited in the study of the kinetics of BSSL against triolein in reversed micelles, which is the subject of Chapter Seven. A detailed description is given of an FT-IR technique which allows one to monitor the course of reaction of biologically important substrates.

A wide range of compounds elicit the sweet taste response but currently it is not known what causes this response. In Chapter 3 a number of sweeteners, and representatives of all the taste groups are investigated using NMR spectroscopy. The T1 relaxation times of the tastants were determined in aqueous solution and in solution with liposomes, a model membrane system. The observed changes in T1, values are analysed to determine which regions of the tastants are involved in the interaction with the membrane. In Chapters 4 and 5 an investigation is reported of the interaction of tastants with a liquid membrane system, which is reportedly able to distinguish between classes of chemicals. The interest lies in developing a simple experiment that will enable taste qualities to be predicted, something that is currently not possible. In Chapters 6 and 7 the NMR assignments of some sweeteners is discussed. NMR assignments are a necessary precursor before their sweetening properties can be studied by NMR.

This work contains some fundamental investigations on Triton X series nonionic surfactants from different aspects. Techniques, such as viscometry, densimetry, diffusion measurement, ultra-violet spectrophotometry, differential scanning calorimetry, surface tension measurement and optical microscopy were employed to acquire the information. Some theoretical analyses were given to the results of these measurements. Triton X surfactants show different properties when they dissolve in different solvents. Aggregation can occur in some solvents, depending on the interactions between solvent and solute. The addition of a surfactant to a solvent will give rise to a solute-solvent interaction and change the solute-solute and solvent-solvent interactions as well. From mass transport properties of the surfactant solutions, these interactions were studied and the contributions to them from each species of the solutions were calculated with a transition-state theory model which is usually used for small molecule systems. Under some reasonable assumptions, a new theoretical method was set up and was able to give a reasonable explanation for the experimental results. The surfactants can also associate with some dyes in both polar and apolar media. The ultra-violet spectra of the surfactant-dye solutions show that surfactant-dye complexes might be formed in the polar and apolar media where the surfactants form regular and reversed micelles respectively. The mechanism of the complexation reactions was studied with equilibrium theory and the charge-transfer nature of the association between the surfactant and dye revealed. The surface tension and. cloud point changes due to the addition of polyethylene glycol were determined to discover the interaction between the water-soluble polymer PEG and the surfactants at the air-solution interface and in the bulk solutions respectively. The mass distribution of the two materials between the two phases produced in the segregation (at the cloud point) of the solutions were determined by their ultra-violet adsorption spectra and densities. The analysis of the cloud point changes was given with the new concepts of polysoap and depletion flocculation. The results show that the size of the micelles, the length of the polymer chains, and the structures of the intra - chain micelles can change the mechanisms of polymer-surfactant interaction and influence the properties of the polymer/surfactant solutions. In a certain range of concentrations, the surfactants aqueous solutions can form liquid crystalline structures which can be observed under a cross-polarised microscope and determined by differential scanning calorimetry. The phase diagrams and their variations with additions of the third component, such as xylene, polyethylene glycol and BaCl2 2H2O have been determined. The effects of temperature and each of the additives on the ordered structures were analysed separately in the light of concepts of spontaneous mean curvature and "salting out" effect. Osmotic coefficients of the surfactant aqueous and methanol solutions were determined with a vapour pressure osmometer, and the activity coefficient of the solvent can be calculated with the osmotic coefficients. The change of the activity coefficient with increase of surfactant concentration shows the interactions of the surfactant with the solvent. In aqueous solution, the addition of surfactant frees the solvent molecules, leading to an activity coefficient larger than 1. In methanol solution, the surfactant addition reduces the fugacity of methanol molecules, resulting in an activity coefficient less than 1. Chemical shift changes of protons of the surfactant molecules in the lH NMR spectra show some information about the configuration of the chains, hydration, and phase structure of the solution system when the surfactant concentration changes over the whole concentration range. From 40% w/w the associated water molecules begin to be lost, and the association number ratio of water molecules and the ethylene oxide unit of the surfactant is 4:1. Electric conductance of electrolytes in the surfactant aqueous solutions are reduced by the addition of the surfactants. The reduction is more significant for large size cations, and the longer the EO chain of the surfactant, the larger the reducing effect on conductance.