A series of new planar complexes with the dianion of 2,3-quinoxalinedithiol ligand has been prepared. The complexes have been characterized from the study of their analyses, magnetic moment, conductance, polarograms, electron spin resonance spectra, and electronic spectra, and compared with the available data on the corresponding maleonitriledithiolene and toluene-3,4-dithiolene complexes.

Although there is consensus on the increasing role of emerging and developing economies in global markets, the literature on the mechanisms contributing to their growth remains still limited. The research aims to contribute to knowledge by exploring and understanding the process of transformation from a centrally planned economy into a market based economy. This transformation process is analysed from the perspective of a Venture Capital industry emerging and developing in Poland. The research focuses on the dynamics of particular factors and their impact on a specific set of stakeholders. In order to take a sufficiently broad contextual view, an organizational theory approach was employed. The Venture Capital industry was treated as a community of organizations which are connected by direct or indirect relationships. The interpretative framework was provided by two leading organizational theories: Institutional theory and Resource Dependence theory. The research is qualitative, and is guided by a specially designed framework for collecting and analysing the data. The primary data were collected though semi structured interviews with Venture Capital industry stakeholders of different types, and with different roles in the process. The research contributes to knowledge at three levels. Firstly, it addresses the literature gap on emergence of the Venture Capital industry in Poland. Secondly, it contributes to an understanding of the process of the emergence of a Venture Capital industry and economic transformation. Thirdly, findings may contribute to policy recommendations formulated to accelerate effective development in financial services.

Cette thèse présente une étude du modèle XY bidimensionnel dans des conditions réalistes, comme la présence d'imperfections (impuretés non magnétiques) ou la taille finie du réseau. Ces deux aspects sont typiques de situations expérimentales et nécessitent un questionnement théorique. Nous avons également considéré le comportement a basse température du modèle d'Heisenberg fini et avons trouve un comportement analogue a celui du modèle XY. Nous avons utilise a la fois une approche analytique et des simulations numériques pour traiter le problème. Les résultats essentiels de ce travail sont: (a) la détermination de l'exposant de décroissance algébrique de la fonction de corrélation du modèle XY dilue, analytiquement avec l'approximation d'ondes de spins et par simulations Monte Carlo a l'aide de l'algorithme de Wolff, (b) l'estimation correspondante dans le cas du modèle d'Heisenberg sur réseau fini a basse température assortie de simulations numériques également, (c) la forme de l'interaction entre les impuretés non magnétiques et les défauts topologiques dans le cadre du modèle de Villain et dans le modèle de Kosterlitz-Thouless, et l'estimation analytique de la réduction de température critique basée sur la forme de cette interaction, (d) la détermination numérique de la distribution de probabilité de l'aimantation résiduelle sur un système fini en présence de désordre. Pour l'ensemble de nos travaux, nous avons obtenu un bon accord entre les prédictions théoriques et les simulations numériques, de même qu'avec des travaux antérieurs le cas écheant. / The thesis presents a study of the two-dimensional XY model exposed to such realistic conditions as the presence of lattice imperfections (nonmagnetic impurities) and lattice finiteness. Both features are typical for experimentally accessible magnetic materials and ask for theoretical description. We also have explored the low-temperature behaviour of a finite two-dimensional Heisenberg model and found behaviour similar to that of the 2D XY model. We have used both analytical and computer experiment approaches to tackle the problem. The essential output of the work consists of: (a) estimation of the non-universal exponent of the power law decay of the pair correlation function of a diluted 2D XY model at low temperature as a function of dilution, analytically in the spin-wave approximation, and in the Monte Carlo simulations using the Wolff algorithm; (b) analytical estimation of the corresponding exponent of the 2D Heisenberg model in the low-temperature limit for the finite lattice size and its comparison to the Monte Carlo simulations; (c) evaluation of the form of interaction between nonmagnetic impurities and topological defects within the Villain model as well as in the Kosterlitz-Thouless model, and analytical prediction of the critical temperature reduction made on the basis of this interaction; (d) Monte Carlo investigation of the form of the residual magnetization probability distribution in a finite system in presence of nonmagnetic disorder (dilution). We found all our analytical predictions in quite well agreement with the Monte Carlo simulation results as well as with other researches of the similar problems.

La O-GlcNAcylation est une glycosylation dynamique et réversible sous le contrôle de la O-GlcNAc Transférase (OGT) qui transfère un résidu de GlcNAc sur les Ser/Thr de protéines intracellulaires, et de la O-GlcNAcase (OGA). Plusieurs travaux dont ceux de notre équipe ont montré l'importance de la dynamique de O-GlcNAcylation pour la progression normale du cycle cellulaire, et plus particulièrement de la mitose. L’objectif de mes travaux de thèse était de comprendre comment la balance O-GlcNAc participe au contrôle des étapes précoces du cycle cellulaire. J’ai d’abord montré dans différentes lignées cellulaires que l’entrée en phase S s’accompagne d’une baisse marquée du niveau de O-GlcNAc, corrélée à une augmentation de l’expression et de l’activité de l’OGA endogène. Par protéomique, 58 protéines cytosoliques et nucléaires différentiellement O-GlcNAcylées à la transition G1/S ont ensuite été identifiées dans les cellules MCF7 synchronisées. Ces protéines interviennent dans des processus cellulaires essentiels à la phase G1 dont la régulation de la transcription, de la traduction et de la mise en conformation des protéines, et de la réplication de l’ADN. Par immunoprécipitation, les variations O-GlcNAc dépendantes du cycle cellulaire ont été confirmées sur les protéines cytosoliques CK8, hnRNP K et Caprine 1, et sur les protéines nucléaires du complexe de pré-réplication, MCM-3, -4, -6, et -7. Ces travaux montrent donc que la transition G1/S est étroitement liée à la dynamique de O-GlcNAcylation et soulignent un rôle potentiel de cette glycosylation dans le contrôle de l’initiation de la réplication de l’ADN et par là même, dans le maintien de l'intégrité génomique. / O-GlcNAcylation is a highly dynamic and reversible glycosylation which is governed by O-GlcNAc Transferase (OGT) that transfers the N-acetylglucosamine (GlcNAc) residue onto Ser/Thr of intracellular proteins, and O-GlcNAcase (OGA). Over the last decade, we and others have shown that dynamics of O-GlcNAcylation was important in regulating the cell cycle progression, and more particularly the mitosis events. The aim of my work was to explore how O-GlcNAc balance is implicated in the control of cellular proliferation by focusing on the early steps in the cell cycle. We highlighted in several cell lines that S-phase entry is associated with a marked decrease in the overall level of O-GlcNAcylated proteins, concordant with an increase in both the expression and activity of endogenous OGA. Then, using a proteomic approach we identified 58 cytoplasmic and nuclear proteins differentially O-GlcNAcylated between G0, G1 and S phases. These proteins are involved in key cellular functions that are essential for G1 and S progression, such as protein folding and translation, transcription or DNA replication. By immunoprecipitation, we further confirmed the cell cycle-dependent O-GlcNAc variations of CK8, hnRNP K, Caprin-1, and MCM -3, -4, -6, and -7 proteins which are part of the pre-replicative complex. To conclude, this study shows that there is a close link between the dynamics of O-GlcNAc and G1/S transition and provides a descriptive overview of differentially O-GlcNAcylated proteins at the G1/S transition, highlighting a potential role of O-GlcNAcylation in the initiation of DNA synthesis and therefore, in the maintenance of genome integrity.

Master of Science / Department of Statistics / James W. Neill

The international community proclaims victory when a conflict-ridden state is able to get rid of the main cause of the conflict. However, all the problems of the state do not end with that victory. It rather triggers a whole new set of problems, which combined with the aftermath of the conflict, leads the country to a larger crisis. Afghanistan, after the fall of Taliban regime in 2001, faced various social, political and economic challenges that marked the beginning of a transition period that was much more challenging than the previous period. In this paper, I discuss the major problems of transition-period Afghanistan and how the handling of these problems has shaped the image of the government inside the country and outside. I look into various variables that have played leading roles in Afghanistan in the past ten years (legitimacy, corruption, and state capacity), analyze their interconnectedness, and examine the state‘s vulnerability, leading to a discussion of whether there is an immediate need for a changed approach by national leadership. I demonstrate the complex interaction of the variables in connection with their impact on economic development. Towards the end, I suggest the need for a balanced approach, including but not limited to the increase in sub- national capacity, which will involve strong leadership from the government to define and divide the functions of various actors involved in the stabilization of the country. We will see that Afghanistan‘s geographical location, its natural capacity and the international support it has been receiving provide it with immense prospect for stabilization and even development, providing that the variables analyzed in the paper are addressed.

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy. / High purity natural type Il a diamond specimens were used in this study. Conducting layers in the surfaces of these diamonds were generated using low-ion dose multiple implantation-annealing steps. The implantation energies and the ion-doses were spread evenly to intermix the point-defects, thereby increasing the probability of interstitialvacancy recombinations and promoting dopant-interstitial-vacancy combination resulting in activated dopant sites in the implanted layers. The process used to prepare our samples is known as cold-implantation-rapid-annealing (CIRA). Carbon-ion and boron-ion implantation was used to prepare the diamond specimens, and de-conductivity measurements in the temperature range of 1.5-300 K were made following each CIRA sequence. An electrical conductivity crossover from the Mott variable range hopping (VRH) to the Efros-Shklovskii VRH conduction was observed when the temperature of insulating samples was lowered. The conductivity crossover temperature Tcross decreases with increasing concentration of the boron-ion dose in the implanted layers, indicating the narrowing of the Coulomb gap in the single-particle density of states near the Fermi energy. (Abbreviation abstract) / Andrew Chakane 2019

MA, Industrial Psychology, Faculty of Humanities, University of the Witwatersrand, 2010 / This study explored the career barriers of black women in middle management through the application of Schlossberg’s Transition Theory. The rationale behind the study was informed by statistics that show that there are few black women in top management, a fact attributable to the double discrimination faced during Apartheid because of their gender and race. The two aims of the study were to explore any career barriers that these women may be experiencing or have experienced as they attempt to advance their careers to top management; and secondly, to explore the coping strategies that these women use to deal with the barriers experienced while attempting to advance their careers. In order to investigate the research questions, nine women who met the criteria of the study participated in semi-structured interviews. The study was qualitative in nature, and the interview transcripts were analyzed through thematic content analysis. The main themes were identified and presented under the 4 S’s: Situation, Self, Support and Strategy. What became apparent from the findings was that the participants were dealing with a dual challenge of gender and race discrimination. They were also dealing with role conflict and other barriers such as politics in the workplace and age discrimination. However, it was found that these women were proactive in confronting their challenges as they engaged in numerous coping strategies including education and social support to cope with the career barriers. Schlossberg’s Transition Theory proved to be an appropriate framework for exploration of the career barriers and thus the application of this theory had implications for theory, organisations and future research.

Nitrides of late transition metals possess interesting properties leading to different technological applications, yet, due to many factors, synthesis and reliable characterization of the physical properties of these materials constitute a big challenge. In this work, we present a detailed firstprinciples investigation of the structural, the electronic and the optical properties of the bulk crystalline MNx (where M = Pd, Pt, Cu, Ag or Au; and x = 1/3, 1 or 2) and ZnN. The studied structural properties include energy-volume equation of state (EOS), equilibrium lattice structural parameters, cohesive and formation energies, relative phase stabilities, bulk modulus and its pressure derivative. By means of the enthalpy-pressure EOS, some possiblepressure-induced structural phase transitions are carefully examined. Electronic properties of the energetically most stable phases are investigated via the analysis of their band structure and their total and partial densities of states (DOSs). The frequency-dependent optical constants (absorption coefficient, reflectivity, refractive index, and energy-loss spectrum) of some phases are derived from the calculated frequency-dependent microscopic dielectric tensor. Our calculations of the structural and the electronic properties are based on density functional theory (DFT) within the projector-augmented wave (PAW) formulation and the generalised-gradient approximation (GGA) to the exchange-correlation functional. In order to improve the calculated electronic structure, and to investigate the optical spectra, we carry out expensive GW0 calculations within the the random-phase approximation (RPA) to the dielectric tensor. Obtained results are discussed within the employed theoretical methods of calculations. Whenever possible, our obtained results are compared with experiment and with previous theoretical studies. We report the discovery of some possible low-energy competitive phases which are more stable at zero pressure than the synthesized and other hypothetical structural phases. To the best of our knowledge, our calculated optical spectra may be considered as the first, and thus, the most accurate, calculations within the many-body perturbation GWA calculations, so far.

Adolescents with Autism and their families experience a significant increase in the number and nature of challenges faced when leaving the structure of the formal education system. Increased support and planning is required in order to prepare for and better manage this period, as a successful transition is associated with family well-being. An ecosystemic approach was used in order to better understand the experiences of the individual, the family, the school and the community during this period. The purpose of this study was to gain an understanding of parent and professional perspectives on various elements of the transition process, including planning and support, predicted outcomes and the feelings experienced, in order to develop awareness, improved planning and consequently; outcomes. A sample of 14 participants (7 parents and 7 professionals) was engaged in semi-structured interviews. The results indicate that both parents and professionals feel an overwhelming sense of fear and uncertainty with regards to the future of the adolescent with Autism; however a sense of optimism and hope also exists, as participants reported effective interventions were beginning to occur. The knowledge and understanding of the needs of these individuals is continuously growing within the parents and professionals who are directly involved in the lives of adolescents with Autism; however increased awareness is required within the community and government sectors in order to gain increased access to resources and services. With the appropriate support, individuals with Autism can experience increased quality of life within residential, employment, social and community settings. The results of the current study are discussed with reference to previous research studies, and recommendations for further research are provided.