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Social learning processes in a citrus farming community of practice

  • Authors: Downsborough, Linda
  • Date: 2007
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1878 , http://hdl.handle.net/10962/d1005859
  • Description: Learning takes place in a number of ways. Situated learning for example, tries to shift the focus from the individual as a learner to the learner participating in the social world and from learning as a strictly cognitive process to a more encompassing view of social practice. The overall aim of this research was to gain a deeper understanding of the ways in which learning takes place in and between members of a citrus farming community, in other words it was to investigate the social learning processes. The research was undertaken in Patensie, a citrus farming community of the Gamtoos River Valley, Eastern Cape, South Africa. Data was generated through the use of interviews and informal discussions with participants together with document analysis, such as minutes of meetings. I also made observations of the learning interactions that were evident and also the interactions that were evident in the area as a whole. The data was analysed in two phases, the first involved reading across the interview transcripts and organizing the data under broad themes while the second phase made use of an analytical framework, a Community of Practice perspective to further analyze and engage with the data. I drew quite strongly on the ideas of situated learning, Communities of Practice and the notion of Legitimate Peripheral Participation (Lave & Wenger, 1991) as a means to understand, interpret and describe the social learning processes. The research highlighted that in this case study, citrus farmers learn in a number of sociological ways, for example through intergenerational learning (in the family), learning from each other in a Community of Practice, learning from private consultants and extensions officers as well as from other organizations and institutions. It also considered how farmers' learning had influenced land use practice in the area. This brought to the fore an emerging partnership with a conservation agent based on providing economic incentives to farmers to engage in sustainable landuse practices. It is hoped that this research may inform future educational endeavours by shedding light on the social learning processes and by drawing attention to key aspects of learning that may previously have been overlooked in research.
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  • Date Issued: 2007

Social workers' experiences of HIV and AIDS intervention in Botswana

  • Authors: Kesamang, Lefhoko
  • Date: 2007
  • Subjects: AIDS (Disease) -- Botswana , AIDS (Disease) -- Botswana -- Epidemiology , AIDS (Disease) -- Botswana -- Prevention
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:9987 , http://hdl.handle.net/10948/532 , AIDS (Disease) -- Botswana , AIDS (Disease) -- Botswana -- Epidemiology , AIDS (Disease) -- Botswana -- Prevention
  • Description: This study endeavoured to explore and describe the experiences of social workers in their intervention with HIV and AIDS clients within the Department of Clinical Services of the Ministry of Health in Botswana. The researcher undertook a qualitative research study, using an exploratory, descriptive and contextual design to explore these experiences as perceived by the social workers. The method of data collection included semi-structured face-to-face interviews, as this was deemed most appropriate to the nature of the study. Data analysis was undertaken according to the outline of Tesch (1990), as stated in Creswell (1994:155). The findings were reported as themes, sub-themes and categories emanating from the data-analysis process. In ensuring the trustworthiness of the findings, the researcher adhered to Guba’s (1981) model (in Krefting, 1991:251). The research findings were subjected to a literature control, and culminated in the compiling of the research report. The research findings centred around the following five themes: · experiences of intervention with HIV and AIDS clients; · challenges in HIV and AIDS intervention; · measures to alleviate challenges of HIV and AIDS intervention; · intervention strategies utilised by social workers; and · suggestions and advice to new social workers. The recommendations resulting from this research project proposed inter alia that social workers need to be trained in specific and specialised areas related to HIV and AIDS intervention in the health setting, and that the support structures and a holistic multidisciplinary service delivery approach need to be put in place to assist social workers to be able to meet the needs of the clients as well as their own needs. Key Words: participants, clients/patient, qualitative, HIV and AIDS, experiences, intervention, strategies.
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  • Date Issued: 2007

Social workers' experiences on the transformation of social welfare from a remedial approach to a developmental approach

  • Authors: Mashigo, Boipuso Stephina
  • Date: 2007
  • Subjects: Social service -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:9990 , http://hdl.handle.net/10948/559 , Social service -- South Africa
  • Description: When the new democratic government came into power, much legislation, policies and strategies were transformed, included was the welfare system that was imbalanced, unjust, discriminatory and inappropriate. It was replaced by a developmental approach that is more just, equitable and appropriate system contained in the White Paper for Social Welfare (1997). Social workers were expected to reform their method of intervention. Consequently, this study will focus on the experiences of social workers as changes were brought into the approaches used in service delivery. The goal of the study is to explore and describe social workers’ experiences on the transformation of social welfare from a traditional remedial approach to a developmental approach. The study was conducted using the qualitative research approach. The research study made use of an explorative, descriptive and contextual design. The researcher used purposive and theoretical non-probability sampling methods to draw the sample. Data was collected through semi- structured interviews. The data was analyzed using Tesch’s eight steps in Creswell (1994:155) and was verified against four criteria that Guba in (Krefting, 1991) developed for testing the trustworthiness of a qualitative study. Based on the findings and conclusion of the study, recommendations were made to the management of the department of social development on how to address the challenges facing social workers on the implementation of the developmental approach. The results will be disseminated by means of a written research report.
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  • Date Issued: 2007

Spermiogenesis, sperm ultrastructure and reproductive tract morphology in cicadas implications for systematic relationships

  • Authors: Chawanji, Abraham Simbarashe
  • Date: 2007
  • Subjects: Cicadas Cicadas -- Reproduction Spermiogenesis in animals
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:5770 , http://hdl.handle.net/10962/d1005458
  • Description: Sperm structure in five species of cicadine cicadas (Albanycada albigera, Azanicada zuluensis, Platypleura capensis, P. hirtipennis and Pycna semiclara) and five species of cicadettine cicadas (Melampsalta leucoptera, Quintilia walkeri, Stagira simplex, Xosopsaltria thunbergi and Monomatapa matoposa) was investigated by light and electron microscopy. In addition, spermiogenesis in cicadas was described; the information was derived from two cicadettines (Diceroprocta biconica and M. matoposa) and three cicadines (Kongota punctigera, P. capensis and P. semiclara). Mature spermatozoa of all species investigated are elongate and filiform, consisting of three distinct regions: the head (acrosome and nucleus), mid-piece and tail. All species produce more than one discrete length of nucleated, motile sperm, a form of sperm polymorphism termed polymegaly. Polymegaly is expressed in three ways; sperm have uni-, bi- or trimodal nucleus and tail lengths. Besides the differences in length, there are also notable differences in the size of nuclei. The anterior parts of sperm heads are embedded in an elongate homogenous matrix forming spermatodesmata. The conical acrosome is deeply invaginated posteriorly, and sits on top of the nucleus. The acrosomal contents are differentiated internally with a tubular substructure and a subacrosomal space. The anterior of the nucleus intrudes into the posterior section of the subacrosomal space. Anteriorly the acrosome is laterally flattened; posteriorly it extends as two tubular processes on either side of the nucleus that gradually decrease in diameter. The homogenously electron-dense nucleus is pointed anteriorly and is generally cylindrical, although posteriorly there is a lateral invagination that extends part-way along the nucleus. This invagination houses fine granular material of the putative centriolar adjunct which does not form in close proximity to the centriole and hence may not be a true centriolar adjunct. The lamellate disposition of the centriolar adjunct material within the sperm-midpiece of cicadettine cicadas is distinct, and separates these cicadas from their cicadine counterparts in which the centriolar adjunct material is non-lamellate. Vesicle-like elements that are associated with both the posterior nucleus and the centriolar adjunct are also found within the invagination. Immediately posterior of and adjoining the centriolar adjunct is a pair of mitochondrial derivatives that are elongated and extend for almost the entire length of the tail. Except for size the architecture of short and long spermatozoa is generally similar in all species. The absence of accessory bodies in cicada sperm suggests that within the Cicadomorpha, the families Cicadidae and Cercopidae are closely related. Only long nuclei were observed in the fertilized eggs of A. zuluensis indicating that sperm with long nuclei might be favoured for fertilization. Spermiogenesis involves: (a) development of the acrosome from a proacrosomal granule; (b) development of the nucleus, characterized by elongation and streamlining with a simultaneous condensation of chromatin; (c) development of the axoneme from the centriole; (d) amalgamation of individual small mitochondria to form elongated mitochondrial derivatives in which cristae are arranged into regularly spaced lamellae; and (f) elimination of cytoplasm. The presence of a manchette, a transient microtubular organelle, which surrounds the acrosome, nucleus and mitochondrial derivatives, is a characteristic feature of spermiogenesis. The gross morphology of the reproductive tract in both male and female cicadas exhibits an organization similar to that in most oviparous insects. The non-functional spermatheca is the only exceptional feature in the female reproductive tract. Its role has been taken over by the common oviduct which, subsequently, has become modified into a swollen, differentiated structure with a dual role of receiving oocytes from the paired ovaries and storage of spermatozoa. Testis mass varies between cicada species; this variation might be linked to the intensity of sperm competition which has been found to be positively correlated with relative investment in spermatogenesis. Based on the preliminary findings of this study, K. punctigera, with its larger testis relative to body size, would be the ideal candidate to show the greatest levels of sperm competition. Accessory glands in both male and female A. zuluensis, D. biconica, P. hirtipennis and O. quadraticollis are very long; this character might be of phylogenetic significance. Despite being notoriously refractory spermiocladistics is potentially valuable in systematic and phylogenic studies of cicadas, especially at the subfamily level.
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  • Date Issued: 2007

Stakeholders' perceptions of parents' involvement in the governance of a Namibian rural school

  • Authors: Niitembu, Martha M
  • Date: 2007
  • Subjects: School management and organization -- Namibia Education -- Parent participation -- Namibia Education and state -- Namibia Rural schools -- Namibia
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1770 , http://hdl.handle.net/10962/d1003655
  • Description: The issue of decentralisation has been one of the top priorities of the Namibian education system since independence in 1990. One of the decentralisation aims was to enhance parental involvement in education by establishing School Boards. However, School Boards and the role of parents in school management have been considered ineffective for several years which led to the promulgation of Education Act 16 of 2001 in which the roles of School Boards are strengthened and clarified. This study sought to investigate School Board members’ perceptions, understanding and experiences of parents’ involvement in school governance more specifically after the implementation of the Education Act of 2001 in 2003. This study is an interpretive case study of one combined rural school in the Ohangwena educational region of Namibia. This research employed three data collection techniques, namely semi-structured interviews, observation and document analysis. The main findings of this study reveal that there is a lack of joint understanding and shared vision between educators and parents in the School Board. This problem underpins other more symptomatic problems, such as lack of accountability in the matter of school finances, differences in understanding the roles of School Board members and lack of parents’ motivation from the school management. The study further reveals the ineffectiveness and insufficiency of the training provided in the past. It highlights some of the challenges that hinder the effective involvement of parents in rural school governance, such as poor educational background among parents, poor knowledge of the English language and poor understanding of educational issues. However the findings also acknowledge parents’ participation and their full involvement in decision-making. The findings show that the new School Board elected in terms of the Education Act of 2001 has been more effective than previous School Boards and has reached a number of achievements such as being instrumental in solving disciplinary problems, purchasing school assets and renovating classrooms. Recommendations for practice and for further research are made.
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  • Date Issued: 2007

Statistical analyses of artificial waterpoints: their effect on the herbaceous and woody structure composition within the Kruger National Park

  • Authors: Goodall, Victoria Lucy
  • Date: 2007
  • Subjects: South African National Parks , Ecology -- Statistical methods , Regression analysis , Log-linear models , Game reserves -- South Africa , Kruger National Park (South Africa)
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5570 , http://hdl.handle.net/10962/d1002810 , South African National Parks , Ecology -- Statistical methods , Regression analysis , Log-linear models , Game reserves -- South Africa , Kruger National Park (South Africa)
  • Description: The objective of this project is to link the statistical theory used in the ecological sciences with an actual project that was developed for the South African National Parks Scientific Services. It investigates the changes that have occurred in the herbaceous and woody structure due to the closure of artificial waterpoints; including the impacts that elephants and other herbivores have on the vegetation of the Kruger National Park. This project was designed in conjunction with South African National Parks (SANP) Scientific Services and it is a registered project with this department. The results of this project will be submitted to Scientific Services in accordance with the terms and conditions of a SANP research project. A major concern within the KNP is the declining numbers of rare antelope and numerous projects have been developed to investigate possible ways of halting this decline and thus protecting the heterogeneity of the Kruger National Park. Three different datasets were investigated, covering three aspects of vegetation structure and composition within the KNP. The first investigated the changes that have occurred since the N'washitsumbe enclosure in the Far Northern KNP was fenced off from the rest of the park. The results show that over the 40 years since the enclosure was built, changes have occurred which have resulted in a significant difference in the abundance of Increaser 2 and Decreaser grass species between the inside and the outside of the enclosure. Increaser 2 and Decreaser categories are the result of a grass species classification depending on whether the species thrives or is depressed by heavy grazing. The difference in grass species composition and structure between the inside and the outside of the enclosure indicates that the grazing animals within the KNP have influenced the grass composition in a way that favours the dominant animals. This has resulted in a declining roan antelope population - one of the species that is considered as a 'rare antelope'. Many artificial waterpoints (boreholes and dams) have also been closed throughout the KNP in the hope of resulting in a change in vegetation structure and composition in favour of the roan. Veld condition assessment data for 87 boreholes throughout the Park was analyzed to determine whether the veld in the vicinity is beginning to change towards a more Decreaser dominated sward which would favour the roan. The results were analyzed for the different regions of the Park; and they indicate that changes are becoming evident; however, the results are not particularly conclusive, yet. The majority of the boreholes were closed between 1994 and 1998 which means that not a lot of data were available to be analyzed. A similar study conducted in another 10 years time might reveal more meaningful results. However the results are moving in the direction hoped for by the management of the KNP. The results show that the grass composition has a higher proportion of Decreaser grasses since the closure of the waterpoints, and the grass biomass around these areas has also improved. The results were analyzed on an individual basis; and then on a regional basis as the minimal data meant that the individual analyses did not provide any significant results. A third study was then done on the impact that the rapidly increasing elephant population on the vegetation within the Riparian zone along three rivers in the Far Northern region of the KNP. The riparian zone is an important part of the landscape, in terms of providing food for many animals as well as shade. The elephant population has increased substantially since the termination of the culling program and this means that the feeding requirements of the population has increased which could result in severe damage upon the vegetation, as elephants can be very destructive feeders. The results show surprising differences between the three years of data that were analyzed; however the results indicate that the elephants are targeting specific height ranges of trees when feeding; however they do not seem to consistently target specific tree species. This is positive for the diversity of the Riparian zone as this region is very important both ecologically and aesthetically for the tourists who visit the Park.
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  • Date Issued: 2007

Strategies for managing work related stress

  • Authors: Müller, Elsie Franscina
  • Date: 2007
  • Subjects: Stress management , Job stress , Work -- Psychological aspects
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8577 , http://hdl.handle.net/10948/742 , Stress management , Job stress , Work -- Psychological aspects
  • Description: The objective of this study was to identify the strategies (primary, secondary and tertiary) that can be employed to manage work related stress. A questionnaire, was designed based on the strategies found in a literature study on the topic and used to gather inputs from academic head of department and lecturers. The questionnaire was delivered by hand to 18 potential respondents. All 16 questionnaires returned could be used. These were processed and analysed using Microsoft Excel spreadsheets. In general support was found for primary stress management strategies pertaining to work schedule, work load and work pace, job content, career development, the home-work relationship and work environment. Lifestyle management in terms of physical activities and a healthy diet were regarded as the preferred secondary stress management strategies. The strategies related to lifestyle management which were identified from the literature study were physical activities, healthy diet, relaxation techniques such as meditation and yoga. Support was found for tertiary stress management strategies but most of the respondents were not sure if their organisation offered any wellness, employee assistance or stress management programmes. Wellness programmes were indicated as a strategy that will have the most impact on reducing work related stress and employee assistance programmes (EAPs) ranked there after. Overall respondents indicated that they did not perceive their work as very stressful.
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  • Date Issued: 2007

Studies towards the development of novel multidentate ligands

  • Authors: Magqi, Nceba
  • Date: 2007
  • Subjects: Density functionals , Ligands , Ligands -- Design , Ligands -- Analysis , Camphor
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4358 , http://hdl.handle.net/10962/d1005023 , Density functionals , Ligands , Ligands -- Design , Ligands -- Analysis , Camphor
  • Description: In this study, attention has been given to the design and synthesis of novel multidentate ligands for use in the construction of ruthenium-based metathesis catalysts, and their chelating potential has been explored by computer modelling at the Density Functional Theory (DFT) level. Both Kemp’s triacid (1,3,5-trimethyl-1,3,5-cyclohexanetricarboxylic acid) and D-(+)-camphor have been investigated as molecular scaffolds for the development of such ligands. However selective elaboration of the functional groups in Kemp’s triacid proved difficult to achieve, and the research has focused on the development of camphor derivatives. The synthesis of the camphor-based ligands has involved C-8 functionalisation and ring-opening of the bicyclic system to afford tridentate products. The formation of 9-iodocamphorquinone bis(ethylene ketal) together with the desired product, the 8-iodo isomer, has been confirmed by single crystal X-ray analysis of both compounds. Formation of the 9-iodo analogue has provided new insights into the intramolecular rearrangement of camphor skeleton, and the mechanistic implications have been assessed by coset analysis. Attempts to effect nucleophilic displacement of the 8-halogeno groups by nucleophilic donor moieties proved unexpectedly difficult and, coupled with the susceptibility of the carbonyl groups to nucleophilic attack, has led to the formation of novel tricyclic products, viz., 1,6-dimethyl-3-(2-pyridylamino)-4-oxatricyclo[4.3.0.0[superscript 3,7]]-2-nonanone and 6,7-dimethyl-3-(2-pyridylamino)-4-oxatricyclo -[4.3.0.0[superscript 3,7]]-2-nonanone. However the diphenylphosphine group was successfully introduced at C-8 and oxidative ring-opening of the camphor skeleton has afforded the tridentate ligands, 2-(diphenylphosphinoylmethyl)-1,2-dimethyl-1,3-cyclopentanedicarboxylic acid and 2-(diphenylphosphinoylmethyl)-1,3-bis(hydroxymethyl)1,2-dimethylcyclopentane. One- and two-dimensional NMR and, where appropriate, high-resolution MS methods have been used to characterise the products. Three [superscript 13]C NMR chemical shift prediction programmes, viz., ChemWindow and the MODGRAPH neural network and HOSE (Hierachially Ordered Spherical description of Environment), have been applied to representative compounds to assess their efficacy. While the predicted shifts correlated reasonably well with the experimental data, they proved to be insufficiently accurate to differentiate the isomeric systems examined.
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  • Date Issued: 2007

Study of metallophthalocyanines attached onto pre-modified gold surfaces

  • Authors: Mashazi, Philani Nkosinathi
  • Date: 2007
  • Subjects: Phthalocyanines , Electrochemistry , Electrodes, Enzyme , Glucose -- Measurement
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4361 , http://hdl.handle.net/10962/d1005026 , Phthalocyanines , Electrochemistry , Electrodes, Enzyme , Glucose -- Measurement
  • Description: Tetra-carboxy acid chloride phthalocyanine complexes of cobalt, iron and manganese were synthesized and characterized using spectroscopic and electrochemical techniques. These complexes were fabricated as thin films on gold electrode following a covalent immobilization and self-assembling methods. Surface electrochemical and spectroscopic characterization showed that these complexes are surface-confined species. The characterization using spectroscopic and electrochemical methods confirmed the formation of thiol and MPc SAMs on gold electrode. The electrocatalytic behaviour of the SAM modified gold electrodes was studied for the detection of L-cysteine and hydrogen peroxide. The limits of detection (LoD) for Lcysteine were of the orders of 10[superscript -7] mol.L[superscript -1] for all the MPc complexes studied and the LoD for hydrogen peroxide at cobalt phthalocyanine modified gold electrode was of the orders of 10[superscript -7]mol.L[superscript -1] for both electrocatalytic oxidation and reduction. The modification process for gold electrodes was reproducible and showed good stability, if stored in pH 4 phosphate buffer solutions and can be used over a long period of time. The cobalt phthalocyanine modified gold electrode was also investigated for the fabrication of glucose oxidase (GOx)-based biosensor and as an electron mediator between the enzyme and gold electrode. The behaviour of the enzyme modified gold electrode towards the detection of glucose was studied and the results gave a limit of detection of the orders of 10[superscript -6] mol.L[superscript -1] with low binding constant (4.8 mM) of enzyme (GOx) to substrate (glucose) referred to as Michaelis-Menten constant. The practical applications, i.e. the real sample analysis and interference studies, for the enzyme modified gold electrodes were investigated. These studies showed that the enzyme electrode is valuable and can be used for glucose detection.
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  • Date Issued: 2007

Study of titanium, tantalum and chromium catalysts for use in industrial transformations

  • Authors: Tau, Prudence Lerato
  • Date: 2007
  • Subjects: Titanium Tantalum Phthalocyanines Electrochemistry Photochemotherapy Chromium Spectrum analysis
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4363 , http://hdl.handle.net/10962/d1005028
  • Description: PART A The syntheses, spectroscopic and electrochemical characterisation of a series of titanium and tantalum phthalocyanine complexes are reported. The complexes are unsubstituted and substituted at either the peripheral or non-peripheral positions with sulphonates, aryloxy, arylthio or amino groups. The complexes mostly exhibit Qbands in the near-infrared region as well as interesting properties in different solvents. The interaction of differently sulphonated titanium and tantalum phthalocyanine complexes with methyl viologen (MV[superscript 2+]), and hence the stoichiometry and association constants are evaluated. Detailed photophysicochemical properties of the complexes were investigated and are for the first time presented with fluorescence lifetimes easily obtained from fluorescence quenching studies. The transformation of 1-hexene photocatalysed by aryloxy- and arylthio-appended complexes is also presented for the first time. The electrochemical properties of the complexes are unknown and are thus presented. Cyclic (CV) and square wave (SWV) voltammetries, chronocoulometry and spectroelectrochemistry are employed in the study of the complexes. Two oneelectron reductions and a simultaneous 4-electron reduction are observed for the unsubstituted Cl[subscript 3]TaPc. Reduction occurs first at the metal followed by ring-based processes. The tetra- and octa-substituted derivatives however exhibit peculiar electrochemical behaviour where a multi-electron transfer process occurs for complexes bearing certain substituents. For all complexes, the first two reductions are metal-based followed by ring-based processes. A comparative study of the electrocatalytic activities of the complexes towards the oxidation of nitrite is also investigated. The complexes are immobilised onto a glassy carbon electrode either by drop-dry or electropolymerisation methods. All the modified electrodes exhibit improved electrocatalytic oxidation of nitrite than the unmodified electrodes by a twoelectron mechanism producing nitrate ions. Catalytic currents are enhanced and nitrite overpotential reduced to ~ 0.60 V. Kinetic parameters are determined for all complexes and a mechanism is proposed. PART B: The syntheses and electrochemical characterisation of chromium and titanium complexes for the selective trimerisation of ethylene to 1-hexene are presented. The synthesis of the chromium complex requires simple steps while tedious steps are used for the air-sensitive titanium complex. The spectroscopic interaction of the chromium complex with the co-catalyst methylaluminoxane is investigated. The complexes are characterised by electrochemical methods such as cyclic voltammetry and spectroelectrochemistry.
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  • Date Issued: 2007

Subtle racism amongst undergraduate learners after a decade of democracy

  • Authors: Van der Westhuizen, Amanda
  • Date: 2007
  • Subjects: Racism in higher education -- South Africa -- Nelson Mandela Bay , Intergroup relations , Social interaction
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:9954 , http://hdl.handle.net/10948/d1018820
  • Description: The concept of “race” has been the organising feature of South African society for more than three centuries. More recent social changes in the United States of America, Europe, Australia, and South Africa have lead to more subtle expressions of racism. The present study aimed to explore and describe subtle racism amongst undergraduate psychology learners at a tertiary institution in Nelson Mandela Metropolitan Municipality in 2004. The Subtle Racism Scale was used to measure anti-Black sentiment among a sample of 286 undergraduate psychology learners, obtained through non–probability, convenience sampling. Multiple regression analysis revealed the independent variables of race, age, and the race-age interaction were significantly associated with subtle racism of the participants. Research results demonstrated that participants’ level of estimated subtle racism varied according to the age and race of the participants, supporting the notion that racism in South Africa did not influence different age and race groups in a uniform manner.
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  • Date Issued: 2007

Synthesis and characterization of symmetrical and unsymmetrical ferrocenyl ligands for use in the preparation of Redox Active Ruthenium Alkylidene Complexes

  • Authors: Saku, Duduetsang
  • Date: 2007
  • Subjects: Ferrocene , Ligands , Asymmetric synthesis
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10403 , http://hdl.handle.net/10948/701 , Ferrocene , Ligands , Asymmetric synthesis
  • Description: Oxidation of a ferrocenyl group in conjugation to another metal centre can alter the electron density at that metal centre and lead to a change in overall reactivity of a complex. Herein, the synthesis and characterization of redox active symmetrical and unsymmetrical ferrocenylalkene derivatives is described. A change in the standard redox potential of ferrocene (465 mV), to more positive potentials in vinylferrocene 1 (478 mV) and 4-phenylvinylferrocene 3 (499 mV), showed how manipulation of a redox potential can be effected on the ferrocenyl moiety by just using conjugation effects. A shift by +13 mV is observed in 1 and this potential more than doubled in 3 (+34 mV). Ferrocenylderived ruthenium alkylidene complexes were also prepared in a cross metathesis of 1 and 3 with Grubbs’ 1 (676.5 mV) to give complexes Ferrocenylidenebis( tricyclohexylphosphine)dichlororuthenium 14, 4-ferrocenylphenylidene-bis (tricyclohexylphosphine)dichlororuthenium 15 respectively. The extent of the electronic communication between the ferrocenyl group and the ruthenium centre was then estimated by looking at the positive or negative redox potential shifts of 14 and 15 as a result of 1 and 3. A large positive potential shift by 180 mV in 14 indicated that there was a strong electronic communication between the two metal centres, while the smaller, yet significant positive potential shift by 89.5 mV in 15 showed 3 to have a lesser effect on the ruthenium centre. Compounds 14 and 15 were tested in a Ring Closing Metathesis (RCM) of diethyldiallylmalonate showed enhanced reactivity.
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  • Date Issued: 2007

Synthesis of novel coumarin derivatives as potential inhibitors of HIV-1 protease

  • Authors: Rose, Nathan Rolf
  • Date: 2007 , 2013-07-01
  • Subjects: Coumarins , Protease Inhibitors , Heterocyclic compounds -- Derivatives , HIV infections -- Treatment
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4430 , http://hdl.handle.net/10962/d1007220 , Coumarins , Protease Inhibitors , Heterocyclic compounds -- Derivatives , HIV infections -- Treatment
  • Description: This research has focused on the development of novel coumann derivatives containing peptide-like side chains as potential HIV-1 protease inhibitors. The reaction of various salicylaldehyde derivatives with tert-butyl acrylate In the presence of 1,4- diazabicyclo[2.2.2]octane (DABCO) has afforded a series of Baylis-Hillman adducts in moderate yield. Cyclisation of the adducts in the presence of HCI afforded the corresponding 3-(chloromethyl)coumarin derivatives, which have been reacted with various amine hydrochlorides in the presence of Proton Sponge® to afford a series of novel 3- (aminomethyl)coumarin derivatives, which were fully characterised by NMR and HRMS methods. Various approaches to the introduction of hydroxyl or amino groups at the C-4 position of coumarin and the 3-(chloromethyl)coumarin derivatives have been explored; these have included dihydroxylation of the coumarin double bond, and the synthesis of 4- benzylaminocoumarin derivatives as potential intermediates. The Vilsmeier-Haack and Mannich reactions have also been investigated as possible methods of introducing the desired peptide-like functionality. Computer modelling of selected structures has indicated that some of the novel 3- (aminomethyl)coumarin derivatives may exhibit activity as inhibitors of HIV-1 protease. The planned enzyme inhibition assays were unfortunately precluded by the aqueous insolubility of the selected compounds. Three ¹³C NMR chemical shift algorithms, viz., Modgraph Neural Network, Modgraph HOSE and Chern Window, have been applied to selected compounds prepared in this study. The Modgraph Neural Network algorithm was found, in all cases, to provide the most accurate correlations with the experimentally-determined chemical shifts. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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  • Date Issued: 2007

Synthesis of P-Methane-3,8-Diol

  • Authors: Mpuhlu, Batsho
  • Date: 2007
  • Subjects: Insect baits and repellents
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:10411 , http://hdl.handle.net/10948/570 , http://hdl.handle.net/10948/d1011717 , Insect baits and repellents
  • Description: The synthesis of para-menthane-3,8-diol in a batch reactor was investigated in some detail with the view to evaluate the potential of producing said p-menthane- 3,8-diol in a continuous-flow reactor from the results obtained from the batch process. The methodology used as base for this investigation was a published procedure by Takasago of Japan. The Takasago-method produced 92.3 percent Yield for the product para-menthane-3,8-diol, and 2.7 percent Yield of the by-product, acetal. The objective for this investigation was to produce a minimum p-menthane-3,8- diol content of 97.0 percent and a maximum content of 3.0 percent for the by-product acetal. The batch production process was evaluated in detail using statistical experimental design methodologies. Three process variables, namely catalyst loading, organic/aqueous phase ratio and reaction temperature were selected for the study. The experimental method was based on the Takasago procedure, however the substrate was added as a single slug as opposed to gradual addition method and the reaction period was reduced to 30 minutes. Apart from statistical analysis, mechanistic aspects were also used to interpret the following results. Using a central composite design, three response models (one for the conversion of citronellal, p-menthane-3,8-diol and acetal formation) were determined. An analysis of the response surfaces indicated that, to increase the citronellal conversion all three variables should be increased. To increase the amount of pmenthane- 3,8-diol, the reaction temperature and acid concentration should be increased, but the Aq/org ratio should be decreased as the acid catalyst concentration is increased. To minimize the amount of acetals formed during the reaction, the Aq/org ratio should be decreased; temperature and acid concentration can be decreased or increased. The reaction mechanism suggested that p-menthane-3,8-diol may be formed along two pathways: One pathway directly forms p-menthane-3,8-diol, whilst the second pathway forms the isopulegol first, then proceeds to form product by hydrolysis. The acetal is formed as result of the reaction between unreacted citronellal and p-menthane-3,8-diol. From the design experiments it was suggested that reaction time can be reduced to 8 minutes at reaction temperatures between, 80-85 0C The product and acetal were isolated by simple vacuum evaporation of the low boiling citronellal and isopulegol. Results from recycling the catalyst phase were similar to those of the initial process. The results of this investigation has clearly shown that with a proper understanding of the effect of process variables on the performance of the batch synthesis route, the conversion of this traditionally batch (actually semi-batch) process into a continuous process is quite feasible provided that suitable equipment is available. The most important features required for such equipment would be: Intense mixing throughout the reaction zone so as to maximise the surface area between the two immiscible phases, hence the rate of mass transfer between the two phases; and the ability to run reactions above the boiling point of water. Plans for the further study of the process are already well underway and sections of static mixing tubes have been acquired to build a continuous lab scale tubular reactor that would be capable of providing the level of mixing required.
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  • Date Issued: 2007

Synthesis of triprenylated toluquinone and toluhydroquinone metabolites from a marine-derived Penicillium fungus

  • Authors: Scheepers, Brent Ashley
  • Date: 2007
  • Subjects: Penicillium , Antineoplastic agents , Marine fungi , Quinone
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4373 , http://hdl.handle.net/10962/d1005038 , Penicillium , Antineoplastic agents , Marine fungi , Quinone
  • Description: This project forms part of a collaborative effort between the marine natural products chemists at Rhodes University and the medical biochemists at the University of Cape Town’s School of Medicine. Our UCT collaborators tested the cytotoxicity of a group of toluhydroquinones and toluquinones (9-15) against the oesophageal cancer cell line WHCO1 and revealed that the triprenylated toluhydroquinone 11 and it’s oxidised analogue 12 were the most active. This thesis presents an investigation into the role of the polyprenyl side-chain in the cytotoxicity of compound 11 and it’s oxidised analogue 12 by synthesizing and testing the cytotoxicity of simplified analogues of this compound. The synthesis of the two ortho-prenylated toluhydroquinone analogues 5-methyl-2-[(2'E,6'E)-3',7' -dimethyl-2',6'-octadienyl]-1,4-benzenediol (19) and 5-methyl-2-[(2'E,6'E)-3',7',11'-trimethyl-2',6',10'-dodecatrienyl]-1,4-benzenediol (21) and their two ortho-prenylated toluquinone analogues, 5-methyl-2-[(2'E,6'E)-3',7'-dimethyl-2',6'-octadienyl]-2,5-cyclohexadiene-1,4-dione (20) and 5-methyl-2-[(2'E,6'E)-3',7',11'-trimethyl-2',6',10'-dodecatrienyl]-2,5-cyclohexadiene-1,4-dione (22) is described. Our initial attempts to couple geranyl bromide, farnesyl bromide and farnesal to the aromatic precursors m-cresol and 1,4-dimethoxy-2-methylbenzene using directed ortho-prenylation and phenoxide carbon-alkylation were unsuccessful. The four target analogues were eventually synthesized via the initial metal halogen exchange reaction between 1-bromo-2,5-dimethoxy-4-methylbenzene and geranyl bromide/farnesyl bromide using n-BuLi and TMEDA in ditheyl ether at 0 °C to yield 92 and 104 respectively in moderate yield. The demethylation of both compounds preceded smoothly using AgO giving the target analogues 20 and 22 in good yield (approx. 90 %). The reduction of quinones 20 and 22 with sodium dithionite gave 19 and 21 in quantitative yield. The synthesis reported here is the first regioselective synthesis of these compounds. The anti-oesophageal cancer activity of 19-22 and two commercially available non-prenylated analogues 17 and 18 were tested against WHCO1. The conclusion drawn from the anti-oesophageal cancer study was that the polyprenyl side-chain plays a negligable role in the cytotoxicity of compounds such as 11 and 9 against the oesophageal cancer cell line WHCO1.
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  • Date Issued: 2007

Synthesis, properties and reactions of Novel Quinone Methides

  • Authors: Taljaard, Jana Heloïse
  • Date: 2007
  • Subjects: Quinone , Chemistry, Organic
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:10408 , http://hdl.handle.net/10948/616 , Quinone , Chemistry, Organic
  • Description: Novel p-quinone methides have been synthesized by the dealkylation of 5-(p-alkyloxyaryl)- 10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ols and related compounds. Aspects of the dealkylation reaction were investigated using computational methods in order to identify possible intermediates and postulate reasons for the observed reactivity patterns. This included studying the effect of varying the size of the central B-ring, changing the alkyloxy group, and altering the substitution pattern on the parent alcohols. We have assessed the relative energies of reaction intermediates and have also evaluated the influence of factors such as charge delocalisation, LUMO properties of the carbocations and thermodynamic factors on the dealkylation reaction. The use of different dealkylating reagents was also briefly investigated. Demethylation of 1,3- dimethyl-11-(4-methoxyphenyl)-6,11-dihydrodibenzo[b,e]oxepin-11-ol with pyridine hydrochloride led to acid-catalyzed ring-contraction of the parent alcohol to form a novel substituted anthraquinone, 9-(4-hydroxyphenyl)-1,3-dimethyl-anthracen-10-(9H)-one, in good yield. The general reactivity of the p-quinone methides of interest to us was explored by subjecting these compounds to reaction with a range of nucleophiles (bases, Grignard reagents and alcohols). A range of aryl Grignard reagents were reacted with the p-quinone methides, with the main product isolated in almost all cases being the aryl-coupled 1,2-addition product. The nucleophilic addition reactions of alcohols were supported by a computational study and a probable reaction mechanism has been postulated. A base-catalyzed rearrangement is proposed to account for the formation of products in which dehydrogenation of the ethane bridge was observed. These studies showed that in these p-quinone methides, chemical reactivity is strongly influenced by steric crowding, resulting in reversal of the normal 1,2- vs. 1,6- selectivities expected for nucleophilic addition. The ketalization process was explored further using diols and thiols. Products analogous to those obtained with the monohydric alcohols resulted from the diols, along with a series of novel bis-ethers. A range of miscellaneous reactions of 4-(dibenzo[a,d]cycloheptan-5-ylidene)cyclohexa-2,5,- dienone and related systems were investigated. Functionalization by epoxidation, dichlorocarbenation and Diels-Alder reactions, photochemical and [2+2] cycloaddition were attempted and reduction and oxidation reactions were also explored. Photochemical demethylation of an ortho-methoxyl substituent on the p-quinone methide system was observed to occur in good yield. The p-quinone methides underwent reductive coupling in the presence of Zn/AlCl3. The electronic spectra of highly conjugated carbocations were obtained and their potential as novel dyes evaluated. A low-temperature Grignard exchange reaction followed by spontaneous cyclization upon workup, was successful in synthesizing the lactone, spiro[10,11- dihydro-5H-dibenzo[a,d]cyclohepten-(3’,4’H)-phenyl-5,2’(5’H)-furan-5’-one], in one step from the starting ketone. A novel seven-membered Malachite Green dye analogue, 11-(4- dimethylamino-phenyl)-3-morpholin-4-yl-6,11-dihydro-dibenzo[b,e]oxepin-11-ol, was also synthesized and its electronic spectra compared to that of the unannulated Malachite Green dye series. All novel compounds synthesized were characterized using NMR, IR and HRMS-analysis.
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  • Date Issued: 2007

Teacher motivation in a South African school

  • Authors: Kovach, John C
  • Date: 2007
  • Subjects: Teacher morale -- South Africa -- Eastern Cape Teachers -- Professional ethics -- South Africa -- Eastern Cape Teacher-administrator relationships -- South Africa -- Eastern Cape Educational leadership -- South Africa -- Eastern Cape
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1790 , http://hdl.handle.net/10962/d1003675
  • Description: This study explores and attempts to shed light on what motivates teachers and how teacher motivation is affected by a principal's leadership style. The worldviews of pragmatism and critical realism were used as the basis for exploring teacher motivation in a South African school. A primary school in the Eastern Cape of South Africa was chosen for the case study. Three data gathering tools, a leadership questionnaire, teacher survey, and interviews were used to generate data on teacher motivation and the interaction between leadership style and teacher motivation. In regards to teachers, religion, social justice, and self-efficacy were all identified as motivators. The principal was strongly charismatic in her leadership and along with transformational and social justice leadership played a major role in influencing teacher behaviors. Self-determination theory was identified as helping to explain different levels of intrinsic and extrinsic motivation and thereby to better understand varying degrees of teacher motivation. There are many difficulties in South African education and around the world in general and this study is premised on the belief that if teacher motivation can be studied and advanced there will be an improvement in education and learning. This thesis was limited in its scope and ability to fully explore the different levels of ontology as outlined by the critical realist and this is identified as a possible future course of action for not only studying teacher motivation but getting to the 'heart of the matter'.
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  • Date Issued: 2007

Teachers' perceptions of the implementation of the arts and culture learning area in the senior phase

  • Authors: Van Blerk, Susan
  • Date: 2007
  • Subjects: Competency-based education , Arts -- Study and teaching (Secondary) , Culture -- Study and teaching (Secondary)
  • Language: English
  • Type: Thesis , Masters , MPhil
  • Identifier: vital:9546 , http://hdl.handle.net/10948/627 , Competency-based education , Arts -- Study and teaching (Secondary) , Culture -- Study and teaching (Secondary)
  • Description: Teachers are the primary implementers of a curriculum as they need to bring the curriculum to life in the classroom. In order to optimize the success of the implementation of a specific curriculum, it is necessary to monitor the experiences of the educator in the classroom and in drawing conclusions from the data gained, make recommendations for the continued improvement of implementation. As mentioned earlier, Fullan’s reference (1991:117) to the significant effect of teachers thoughts on the implementation gave rise to the central research question, namely to determine teachers’ perceptions about the implementation of the Arts and Culture learning area at a particular school ‘Perceptions’ however, is a subjective concept and thus any form of quantitative research would appear to be inappropriate. Based on the above it was decided to approach this investigation qualitatively and so this project was done within the qualitative paradigm.
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  • Date Issued: 2007

Teachers' perspectives on the implementation of life orientation as a learning area

  • Authors: Panday, Dhevina
  • Date: 2007
  • Subjects: Life skills -- Study and teaching , Teachers -- South Africa -- Attitudes , Education -- South Africa -- Curricula
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:9551 , http://hdl.handle.net/10948/590 , Life skills -- Study and teaching , Teachers -- South Africa -- Attitudes , Education -- South Africa -- Curricula
  • Description: The aim of this research project then was to investigate a particular dimension related to the implementation of the Life Orientation learning area within a particular rural primary school in the Kwa-Zulu Natal region. Since the teacher has been identified as a key role player in the successful or unsuccessful implementation of a new curriculum, the primary focus was on the teacher per se. Fullan’s emphasis (1991:117) on teachers’ thoughts (what they think) and actions (what they do), raises two subsequent questions, namely What do teachers at this particular school do with regard to the implementation of the (new) Life Orientation learning area? and What do these teachers think about the implementation of the (new) Life Orientation learning area? In this study, I focused on the second question, namely What do teachers think about the implementation of the (new) Life Orientation learning area? Within the context of this study, it is assumed that the teachers’ thoughts also include their opinions, viewpoints, attitudes and beliefs about the implementation of the Life Orientation curriculum. The term ‘perspective’ has thus been used as encompassing term and the main research question defined as What are teachers’ perceptives about the implementation of the (new) Life Orientation learning area?.
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  • Date Issued: 2007

Teenage pregnancies as a management issue in township schools in George

  • Authors: Sethosa, Grace Sibongile
  • Date: 2007
  • Subjects: Teenage pregnancy -- South Africa , Sex instruction for teenagers -- South Africa
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:9543 , http://hdl.handle.net/10948/678 , Teenage pregnancy -- South Africa , Sex instruction for teenagers -- South Africa
  • Description: This study investigates the causes, consequences and possible solutions of teenage pregnancy. It indicates that socio-economic factors play an important role in the occurrence of teenage pregnancies. In addition the study suggests that a range of factors, including, cultural norms and individual needs, impact on the childbearing decisions of teenage females. The study demonstrates that the most important negative consequences of teenage pregnancy include dropping out of school, unemployment, single parenthood and higher levels of poverty. An important finding of the study is that policies and programmes aimed at reducing teen pregnancy rates, and eliminating the negative consequences experienced by teen mothers and their children, are unlikely to be fully effective unless they realistically address socio-economic imbalances faced by many young women in South Africa.
  • Full Text:
  • Date Issued: 2007
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