This research expands the current body of export performance research by examining the factors influencing export performance among private sector exporting firms in a developing country, namely Saudi Arabia. This study identifies the internal and external factors that influence firms' export performance, empirically examines those factors' influence on export performance, and derives guidelines for both managers and government policy makers concerning the best policies and strategies for improving export performance. Based on the existing literature, a theoretical model for the relationship between export performance and sixty-five independent variables was developed. Three measures of export performance were operationalised: export intensity, export sales growth, and export profitability. The independent variables included both internal and external variables. Internal variables were grouped under firms' differential advantages, export marketing strategy, and management quality. External variables were grouped under local market environment, national environment, and foreign market environment. The analysis and hypothesis testing were carried out for each measure separately. The hypotheses were tested using data collected by means of mail questionnaire from 154 exporting manufacturing firms in Saudi Arabia. Additional data were collected through six in-depth interviews. The results of the analysis revealed the importance of many internal and external factors in influencing firms' export performance. These results differed across different export performance measures. For example export intensity was explained significantly by export marketing strategy, export sales growth was a function of management quality, and export profitability was explained mainly by firms' differential advantages. Moreover, external variables were found to explain export performance. Export intensity was associated positively with exporting to Asia and export profitability was positively associated with exporting to Arab countries.

Glioblastoma is the most common primary malignant brain tumour in the adult population. Despite multimodality treatment with surgery, radiotherapy and chemotherapy, outcomes are very poor, with less than 15% of patients alive after two years. Increasing evidence suggests that glioblastoma stem cells (GSCs) are likely to play an important role in the biology of this disease and are involved in treatment resistance and tumour recurrence following standard therapy. My thesis aims to address two main aspects of this research area: 1) optimization of methods to evaluate treatment responses of GSCs and their differentiated counterparts (non-GSCs), with a particular focus on a tissue culture model that resembles more closely the tumoral niche; 2) characterization of cell division and centrosome cycle of GSCs, investigating possible differences between these cells and non-GSCs, that would allow the identification of targets for new therapeutic strategies against glioblastomas. In the first part of my project, I optimized a clonogenic survival assay, to compare sensitivity of GSCs and non-GSCs to various treatments, and I developed the use of a 3-dimentional tissue culture system, that allows analysis of features and radiation responses of these two subpopulations in the presence of specific microenvironmental factors from the tumoral niche. In the second part, I show that GSCs display mitotic spindle abnormalities more frequently than non-GSCs and that they have distinctive features with regards to the centrosome cycle. I also demonstrate that GSCs are more sensitive than non-GSCs to subtle changes in Aurora kinase A activity, which result in a rapid increase in polyploidy and subsequently in senescence, with a consistent reduction in clonogenic survival. Based on these findings, I propose that kinases involved in the centrosome cycle need to be explored as a novel strategy to target GSCs effectively and improve outcomes of glioblastoma patients.

This thesis comprises three parts, Parts A, B and C. Part A commences with a very brief survey based on the chemical literature of the concept of aromaticity. A number of excellent reviews covering both the historical and theoretical aspects of this subject have appeared recently and, in view of this, a more detailed consideration of aromaticity was deemed unnecessary. This is followed by a discussion of the chemistry of the mulenes with particular emphasis on the theoretical aspects of the subject. The chemistry of perinaphthene and its derivatives is then reviewed in detail and this leads logically to a reasoned description of the aims of the experimental investigation. Part B is a discussion of the results achieved in the course of investigations centred on the perinaghtene nucleus. Part C is devoted entirely to a description of experimental details, and is the complement to part B.

1) The literature covering the fields of isoprenoid quinones, leaf carotenoids and gradient elution chromatography has been comprehensively reviewed, the latter with particular reference to the methods available for the production of concentration gradients. The literature concerning the other lipid components of the chloroplast, together with the role of lipids in photosynthesis, has also been reviewed, although to a lesser extent. 2) A system for the production of complex concentration gradients has been devised, based on the use of a multi-chamber apparatus with the chambers connected in series by means of pumps. With the aid of the Computer Laboratory, the gradients produced by such a system have been examined and some general principles governing such gradients have been discussed. 3) The gradient producing system above has been used in the development of a semi-automatic, gradient elution chromatographic assay method for the plant quinones, and this method has been used to study the variation of these quinones throughout the growing season. This method appears to be more accurate and reproducible than those at present in use, as well as achieving more rapid analysis. 4) Thin layer chromatography has been used, in both adsorbent and reversed phase applications, together with reversed phase paper chromotography, to examine the caroten-oids and guinones present in leaves. Various other lipids present have also been studied, including the plant chromanols. 3) A thin layer technique for the separation of leaf carot-noids has been developed from 4) above and this, combined with spectrophotometry, has been used as a rapid assay method for the detection and estimation of the leaf carotonoids. 6) The development of carotenoids, chlorophylls and quinones on illumination of etiolated tissue has been-examined, using the techniques summarised in 3) and 5) above, together with a standard spectrophotometric assay the chlorophylls.

The adenovirus type 2 origin of DNA replication is located within the terminal 51 bp of the viral genome and contains three recognisable domains: the minimal origin or 'core' and binding sites for the cellular transcription factors Nuclear Factor I and Nuclear Factor III. Initiation of Ad2 DNA replication is preceded by the assembly of a nucleoprotein complex at the viral origin of DNA replication. Recombinant baculoviruses were previously constructed which express full-length Nuclear Factor I (NFIFL) or its DNA binding domain (NFTDBD) for use in experiments. DNase I footprinting experiments were carried out to examine the cooperative interaction between NFI and DBP. DBP can increase the binding affinity of both NFIFL and NFTDBD for their recognition site in the Ad2 origin of DNA replication. Mini-columns containing NFIDBD covalently linked to CNBr-activated Sepharose were used to demonstrate that the adenovirus DNA polymerase (pol) interacts with NFI on its own and as part of the precursor terminal protein (pTP)-pol heterodimer. Immunofluorescence experiments have shown that NFI is specifically targeted to sites of ongoing viral DNA replication in Ad2 infected cells but not in Ad4 infected cells. This localisation of NFI to discrete subnuclear sites reflects the requirement for NFI for efficient initiation of Ad2 DNA replication. The viral transcriptional activator Ela is also localised to discrete subnuclear sites which are very different from those of DBF and are cell cycle dependant. Antibodies to RNA polymerase II show that although its cellular distribution is also cell cycle dependant it is different from both DBF and Ela. When the sites of active transcription were labelled in Ad2 infected cells they were shown to be distinct from both the Ela and RNA polymerase II nuclear distribution.

Motions of plasma in magnetic structures in the solar atmosphere may be successfully modelled using the theory of magnetohydrodynamics (MHD) describing oscillatory motion, in the form of standing and propagating waves, and unstable behaviour. In this thesis we consider two forms of magnetic structuring, the current sheet and the thin magnetic flux tube. The current sheet finds particular application in the solar corona and solar wind; the thin flux tube is of particular importance in solar photospheric magnetism. A model of a current sheet with a continuous magnetic field profile is studied as a waveguide. The equation of motion for small perturbations to a current sheet equilibrium is obtained from the equations of ideal linear MHD and solved numerically to determine the nature of magnetoacoustic waves propagating parallel to the applied magnetic field. A number of approximation methods are used to shed light on the significance of the numerical results. We consider a variation of this model, applicable to the solar corona, and examine the possibility of impulsively generated magnetohydro dynamic waves in the sheet. Such waves exhibit wavepacket properties, similar to those found in slab models of magnetic structures. The process of convective collapse in a vertical magnetic flux tube located in the solar photospheric network is treated using the thin flux tube equations of ideal linear MED. We consider the critical stability of a thin flux tube embedded in convection zone models of varying complexity, taking into account the effects of an overlying chromospheric atmosphere and temperature imbalance between the flux tube and its environment. The dependence of the instability on various sets of boundary conditions is discussed; the choice of boundary conditions is a subject of some debate in the current literature. Possible future directions for work which extends the description of dynamic phenomena in both the current sheet and thin flux tube structure is discussed and ideas for linking these areas of research are presented.

Hydroxymethylation catalysis provides a valuable strategy for the high volume production of alcohols from α-alkenes. Generally this involves a hydroformylation-hydrogenation sequence, but the capacity to optimise selectivity for each transformation is limited. Condensation reactions between aldehyde products and alcohol products frustrate process economics. By an alternative scheme, all relevant bond-forming reactions occur in a single mechanism. This thesis describes several approaches to catalyst development and the application of derived systems for the hydroxymethylation of allyl alcohol. A review of auto-tandem hydroxymethylation and domino hydroxymethylation is presented in Chapter 1. In Chapter 2 the synthesis of bis-(diethylphosphine) ligands based on a modular series of chiral alicyclic scaffolds is described. High pressure NMR studies have shown that the catalytically active complex [RhH(CO)₂(L-L)] adopts preferentially ea geometry, with [Rh(CO)(L-L)(μ-CO)]₂ as the primary competing species. Catalyst performance can be correlated with the flexibility of the chelating ring; this favoured a high monomer/dimer ratio which enhances activity, but could not rigidify the configuration of the diethylphosphine groups which inhibits linear selectivity. Deuterium labelling studies were suggestive of a domino hydroxymethylation scheme. From the rhodium-hydroxyalkyl-hydride-carbonyl cation, a reductive elimination furnishes the diol derivatives and a β-hydride abstraction furnishes the hydroxyaldehyde derivatives. Up to 53 mol% selectivity to 1, 4-butanediol was attained. The catalysts could be recycled via biphasic separation, however poisoning by methacrolein caused a decline of activity upon reuse of the solution. An investigation of enhanced specific activity via the meta-effect is the subject of Chapter 3. The effect of systematic meta-substitution in triphenylphosphine upon physicochemical properties was investigated by IR spectroscopy and electrochemistry, both of which showed no significant structural impact on the uncoordinated triarylphosphine. Variable temperature ¹H NMR studies however revealed a change in the solution dynamics of the corresponding Vaska complex. The activation barrier to phosphorus-(ipso)carbon rotation increases as a function of meta-substitution, with rotation of substituted aryl rings past each other being more strained. This should create a well-defined coordination sphere around rhodium, and is proposed to account for the high linear selectivity observed in the hydroformylation of allylic alcohols with [RhH(CO){(3, 5-Me₂Ph)P}₃]. Linear-selectivity reached 96 mol%. Catalyst recycling was executed via biphasic separation, retaining on over twelve cycles an average of ~ 94 % efficiency. The kinetics of allyl alcohol hydroformylation with [RhH(CO){(3, 5-Me₂Ph)P}₃] was found to be well represented by Equation 11 (Section 3.6) A detailed analysis of how substrate-specific the influence of the meta-effect remains to be performed. In Chapter 4 domino hydroxymethylation by multi-component L-L/PEt3/Rh systems is described. The regioselective performance of a diphosphine rhodium catalyst in hydroformylation was translated for hydroxymethylation upon introduction of triethylphosphine at a L-L/PEt3 molar ratio ≥ 1. The highest observed selectivity to 1, 4-butanediol was 66 mol%. Competitive activity of triethylphosphine-modified rhodium species presumably accounts for the reduced linear selectivity observed when L-L/PEt3 molar ratio < 1. Despite aggravated catalyst decomposition at higher triethylphosphine concentrations, heterogeneous hydrogenation does not appear to take place. Deuterium labelling studies also discount a sequential homogeneous hydrogenation. There is evidence for the activation of a tris-phosphine-modified rhodium-acyl-carbonyl complex, but such a species could not be isolated from complexation reactions with a variety of precursors. It would be of interest to determine alternative promotors and to establish whether it is preferential to employ a high concentration of mildly acidic species or a low concentration of highly acidic species. The self-assembly of DNA base pair analogues 2-N-pivaloylaminopyridyl phosphine and isoquinolyl phosphine, each modified with diphenylphosphine, diethylphosphine, dicyclohexylphosphine and bis(3, 5-dimethylphenyl)phosphine, is described in Chapter 5. In the presence of a rhodium precursor, exclusive formation of the heteroleptic complex was observed. Although the intramolecular hydrogen-bonding network is sensitive to temperature and free hydroxyl functionalities, highly regioselective catalysts were generally afforded under the appropriate operating conditions. Only the catalyst based on the bis(dicyclohexylphosphine)-heterodimer performed poorly, presumably due to the formation of mono-phosphine complexes. High chemoselectivity was correlated with the heterodimer acidity constant, however this is rendered non-linear by a trans influence when electronic distinction between the platforms is high. Overall, complexes based on the assembly of a dicyclohexylphosphine platform and a bis(3, 5-dimethylphenyl)phosphine platform were found to be optimal; up to 73 mol% selectivity to 1, 4-butanediol was reached. It has been demonstrated in this thesis that in order to effect linear-selective domino hydroxymethylation of allyl alcohol, two distinct transition state structures must be optimised. High regioselectivity demands an asymmetric rhodium-hydride-dicarbonyl complex, which can be generated by an asymmetric chelate or by rigidifying the configuration of the substituents on phosphorus. Interestingly, chelation geometry in this transition state has little impact on this parameter. It has been shown that domino hydroxymethylation is activated by an electron-rich rhodium-acyl-dicarbonyl. The state of electron density on rhodium can be controlled by the substitution pattern on the phosphorus donors, but can also be changed by the inclusion of a suitable promoter. The chelation geometry in this transition state is more significant; placing the acyl functionality trans to a phosphorus donor concentrates the electronic effect in the rhodium-alkyldiol-hydride-carbonyl cation to such an extent as to impede hydride migration and reductive elimination of the diol, favouring β-hydride abstraction and reductive elimination of the hydroxyaldehyde.

Glioblastoma multiforme (GBM) is the most common and most aggressive type of primary brain tumour. It is currently treated by a mixture of ionising radiation and Temozolomide (TMZ) chemotherapy, however virtually all patients experience disease recurrence and 75% die within two years of diagnosis. Tumours which express elevated levels of the DNA repair protein O6-methylguanine DNA methyltransferase (MGMT) have a particularly poor prognosis, suggesting that levels of MGMT and the inefficacy of treatment are linked. MGMT is a “suicide” repair protein that binds irreversibly to a DNA adduct (such as those caused by TMZ) and is destroyed by the proteasome once repair has taken place. Therefore the ability of the cell to repair DNA damage relies on the rate at which it can resynthesise MGMT. Previous research has shown that reducing MGMT levels via promoter silencing increases the effectiveness of treatment, however this causes toxicity in bone marrow stem cells and is therefore unable to be used as a possible treatment option. My preliminary data suggests that inhibition of mTOR signalling reduces the steady state levels of MGMT without affecting mRNA levels, potentially making them more sensitive to TMZ treatment. I am therefore using inhibitors of the mTOR pathway and associated proteins, which have been selected via a novel bioinformatic technique, to ascertain how these affect MGMT protein levels and to determine whether a mixture of these inhibitors with DNA damaging agents could be used to increase the efficacy of TMZ treatment.

How shall we continue to speak of God's love in a world which continues to be flagrantly frustrated by human injustice? The question is not so much concerned with theodicy as with the task of human loving. Loving justly, so that ever wider structures of justice are made possible in history, must be a human endeavour which correlates with a divine precept, mandate, and command. Indeed, Christians are 'commanded' to love, both "one another" and the neighbour as oneself, in correspondence with the love revealed and exemplified by Christ. The 'thesis' developed in this research is given, to the Church and to the world, in Jesus' word to his disciples: As the Father has loved me, so I have loved you. Dwell in my love. If you heed my commands, you will dwell in my love, as I have heeded my Father's commands and dwell in his love ... This is my commandment: love one another, as I have loved you. (John 15:9-12) The task of loving is a problem of authentic correlation. We must first reflect upon the ministry of Jesus, and upon the sort of love or loves which he exemplified among his contemporaries. Then we must discover ways of interpreting the commanded love for our own day, and of putting such a love into practice. The quest for justice parallels and criticizes our quest for love. New Testament scholarship and theological reflection of the nineteenth and twentieth centuries have interpreted Christian love in many ways. As a convenient starting point for evaluating interpretations of Christian love, the proposition is suggested that an appropriate practice of love, correlating with the love of Christ, should lead, if ever so subtly, to the creation of justice in contemporary societies of human beings, and provide foundations for greater justice in future societies. A 'symposium' of selected 'speakers' on the characteristics of Christian love is 'convened'. From the nineteenth century we consider the thoughts of Ludwig Feuerbach and Soren Kierkegaard, and briefly, of the 'young Hegel'. These thinkers set the tone for much of the discussion, and in their ideas are distinguished certain dominant themes which will continue to characterize love-talk in the twentieth century. The twentieth century discussion takes the form of a 'debate' between 'neo-orthodox' Protestants, Latin American 'liberation theologians', and North American 'theologians of process'. But the debate is complicated, because the lines of division are not always distinctly drawn. We consider the most germane propositions of Anders Nygren, whose strict division between agape and eros has had a continuing impact upon Christian theology. Briefly we compare the thoughts of Emil Brunner, Reinhold Niebuhr, John Burnaby, and Karl Barth, and their impact upon the discussion of Christian love which began with Nygren's radical definitions. We observe, for example, how Karl Barth moves away from the early 'neo-orthodox' concerns, answering the critics of neo-orthodoxy with a holistic interpretation of love which melts into action, not determined, but sustained, by the covenanted love of God for his creatures. The latter part of this 'symposium' is an attempt to hear, without prejudging, two of the most prominent interpretations of love in contemporary thought. The Latin American theologians of liberation, since the late nineteen-sixties, have projected a view of Christian love which is thoroughly interpolated with the call for justice, on their continent especially, and also throughout the world. Their viewpoints elevate the discussion to a new plane, in which theory and practice are profoundly interdependent. Although Alfred North Whitehead wrote in the early twentieth century, his followers, in the United States specially, have begun to build upon his ideas, so that the 'process theology' of the eighties is intimately related to Whitehead's work in the twenties. Although the literature is massive, a hearing of Whitehead himself seems import if his ideas about love are to be set in relation to the genre which he inspired. Influenced significantly by the synthesizing method of Whitehead, the concluding chapter aims at no definitive conclusion. However, in recognition of the criterion that love should be creative of justice, certain related issues are distinguished which might inform theology's love-talk for the future. For example, recent textual analysis of the New Testament has demonstrated that the word agape has no consistent usage in the Bible as a word for love superseding all others. The perpetuation of agape as a ‘technical' word for a definite ‘type' of love, is not justified by scripture, and may obscure the profound intimacy of love to justice. Similarly, the relationship of faith to Christian love has the capacity to militate against love's relation to justice. The idea of eros may entail elements of Christian love and justice not normally construed by interpretations of agape. Response to God's love may be inhibited by exclusive, elite, or essentially egocentric characterizations of Christian love. Other insights pertinent to love's relation to justice, its affiliation with feeling, and its universal quality, are suggested.

The purpose of this study was to: 1. develop indices which would demonstrate by a ranking process the relative attractiveness of various competitors of labor in an area and to apply this tool to a sample to determine its feasibility of operation; 2. determine which job factors have the closest association to the overall image; and 3. identify which biographical variables vary significantly with the overall image. The method by which this objective was accomplished consisted of a questionnaire which was administered to 224 high school seniors in the Christiansburg-Radford area of which 182 were applicable in this study. Two indices were constructed to accomplish the first objective: 1. an index of preferability or overall image index, and 2. an index of desirability or treated image index. These two indices were found to be identical in the rankings of the firms which indicates that they validly confirm or support one another. By the use of coefficients of correlation the second objective outlined above was accomplished. This study found that certain job factors do have a close relationship with the overall image. The five job factors analyzed were those appearing in the cluster obtained from the students’ rankings of job factors in the last question of the questionnaire. The major finding here was that although job security is the students' most important job factor, it has a slight relationship to the overall image. An analysis of variance was utilized to accomplish the third objective outlined above. It was found that certain biographical variables do not vary significantly with the image of a firm an individual possesses. The firm itself or the character traits which make up the firm's personality have the greatest effect on the students' image of firms as employers. A recommendation for further study would be to alter the sample used in this study from graduating high school seniors to unemployed workers in the area to determine if their image indices would differ significantly from those in this study. / M.S.