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Comparative electrochemistry and electrocatalytic activities of cobalt, iron and manganese phthalocyanine complexes axially co-ordinated to mercaptopyridine self-assembled monolayer at gold electrodes

  • Authors: Ozoemena, Kenneth I , Nyokong, Tebello
  • Date: 2006
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/286054 , vital:56234 , xlink:href="https://doi.org/10.1016/j.electacta.2005.08.007"
  • Description: Comparative surface electrochemistry and electrocatalytic properties of solid ultrathin monolayer films of metallophthalocyanine (MPc) complexes of cobalt (CoPc), iron (FePc) and manganese (MnPc) self-immobilised, via axial ligation reaction, onto preformed 4-mercaptopyridine self-assembled monolayers (SAMs) on gold electrodes have been described. Surface electrochemical parameters of the modified electrodes showed that these MPc-SAMs are densely packed with flat orientations. The electrochemical, electrocatalytic and stability properties of these MPc complexes follow this order: FePc > MnPc > CoPc. This finding is remarkable as it suggests that the success of using this method of self-assembling of MPc onto gold electrode is largely dependent on the bond distance between the pyridine linker and the central metal of the MPc; the shorter the distance, the faster the co-ordination and the better the electrocatalytic properties towards L-cysteine and thiocyanate. Thus, the superiority of FePc-based SAM over those of the MnPc and CoPc, has been proposed to be the result of the more favorable axial co-ordination properties of FePc with pyridine (i.e. shorter Fe–N(pyridine) bond length.
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  • Date Issued: 2006

Comparison of satellite rainfall data with observations from gauging station networks

  • Authors: Hughes, Denis A
  • Date: 2006
  • Language: English
  • Type: text , Article
  • Identifier: vital:7079 , http://hdl.handle.net/10962/d1009748
  • Description: Networks of ground-based hydro-meteorological observations are frequently sparse in developing countries and the situation is not improving. Part of the reason is the lack of resources available in countries which have more pressing economic and social issues. However, these are also the very countries where improved estimates of water resource availability are required. While hydrological models have the potential to provide the necessary information, without adequately accurate climate (rainfall, evaporation, etc.) input information, it is extremely difficult to establish models and generate representative water resource availability information. This paper reports on a preliminary analysis of the potential for using satellite derived rainfall data through a comparison with available gauge data for four basins in the southern Africa region. It is clear that the satellite data cannot be used directly in conjunction with historical gauge data. Specifically, the satellite data do not reflect the strong influences on precipitation of topography in some of the basins. However, the prospects of applying relatively straightforward adjustments are promising and further assessments appear to be justified.
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  • Date Issued: 2006

Comparitive study of automation strategies at VW Germany and South Africa

  • Authors: Wessel, Oliver
  • Date: 2006
  • Subjects: Volkswagen (Firm) , Motor vehicle industry -- Automation Comparative studies
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9607 , http://hdl.handle.net/10948/823 , Volkswagen (Firm) , Motor vehicle industry -- Automation Comparative studies
  • Description: This master thesis analyses the Volkswagen assembly lines of the Golf A5 manufacture in the mother plant in Wolfsburg, the Touran manufacture in the Auto 5000 GmbH in Wolfsburg as well as the Golf A5 manufacture in Uitenhage in South Africa - all with regard to the level of automation. The target of the analysis is the determination of the optimal level of automation in the three production sites and therefore, the investigation of the potential to automate, or rather to deautomate in particular sections of the assembly in the prevailing production locations. The three production sites are to be investigated with regard to costs, quality and quantity.
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  • Date Issued: 2006

Competing interests and change within the pharmacy education system in South Africa

  • Authors: Allan, Lucie
  • Date: 2006
  • Subjects: Pharmacy -- South Africa Pharmacy -- Study and teaching -- South Africa Pharmacy -- Practice -- South Africa Community pharmacy services -- South Africa Community health services -- South Africa
  • Language: English
  • Type: Thesis , Masters , MPharm
  • Identifier: vital:3741 , http://hdl.handle.net/10962/d1003219
  • Description: This thesis provides a historical account of the emergence of the pharmacy education system in South Africa, and an analysis of the influence of competing interest groups over the pharmacy education curriculum. It provides a critical evaluation of structural-consensus and micro-interpretive approaches to medical and pharmacy education, and sets out a macrointerpretive account of pharmacy education in South Africa. Following Margaret Archer (1979) it analyzes three forms of negotiation between competing interest groups in their efforts to change the pharmacy curriculum; these are political manipulation, external transaction and internal initiation. The thesis argues that whilst the private sector interest group (comprising of retail, wholesale and manufacturing pharmacy) dominated the pharmacy education system until 1994, since then a newly emerged government interest group has begun to compete for educational control. The priorities pursued by this interest group have consistently reflected the objectives set out in the ANC National Health Plan of 1994. The thesis maintains that given its frustration over the non-implementation of the ANC’s health policy objectives, the government interest group is likely to resort to direct political manipulation by passing legislation to alter the content of the current pharmacy curriculum. Such changes would seek to ensure that the syllabus more accurately reflects the ANC Plan’s community health and primary health care objectives. The thesis asserts that such an outcome (of direct political manipulation of the curriculum) is not inevitable, and can be avoided through a process of internally initiated change. It presents the findings of an interpretive case study into how the Rhodes University Community Experience Programme (CEP) influenced final year pharmacy students’ perceptions of the role of the pharmacist. The students’ comments were collected by means of focus group interviews, participant observation and documentary analysis. Whilst the CEP did not successfully transform their concept of the pharmacist’s role, it did succeed in influencing students’ understanding of the notions of community pharmacy and primary health care in line with the government interest group’s health objectives. This thesis concludes that internally initiated change within the pharmacy education system, would be preferable to that imposed through external political manipulation, as such change would be more likely to preserve the independent professional interests of pharmacy academics.
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  • Date Issued: 2006

Composition portfolio

  • Authors: Wynne, Donovan
  • Date: 2006
  • Subjects: Music -- South Africa Composition (Music) String quartets -- Scores
  • Language: English
  • Type: Thesis , Masters , MMus
  • Identifier: vital:2658 , http://hdl.handle.net/10962/d1003121
  • Description: Introductory remarks: Being a middle-class white South African, I grew up on a diet of predominantly "white" music: rock, pop and Western classical music. I was later introduced to a broader range of musics: blues, jazz, kwaito and traditional Southern African idioms. I found myself particularly attracted to the traditional music of the amaXhosa (especially that of the uhadi bow), possibly due to the fact that this music is hexatonic (that is, based on two major triads whose tonics are one tone apart), a system that bears certain resemblances to the Western tonal idiom. However, much of my musical experience tended to be entrenched in the piano and flute music I played: mostly works by composers who were neatly ensconced in the traditional Western canon. Therefore, despite the broad range of musics with which I was familiarisedduring my tertiary studies, I feel that this early experiential background is the reason I feel most comfortable with Western-influenced music. More recently, I discovered a whole new genre to explore: film music, particularly the work of Elliot Goldenthal, Danny Elfman, John Williams and Philip Glass, whose unique brand of minimalism has extended from the concert hall to thefilm theatre. I am fascinated by the ways in which film scores function. A "main titles" theme usually appears as the film opens, upon which most of the subsequent music is based. This is not a linear process, like a theme and its variations, but a lateral, where the main titles theme is the core that engenders other themes that all share a familial resemblance.
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  • Date Issued: 2006

Composition portfolio

  • Authors: Webb, Cassidy Frank
  • Date: 2006
  • Language: English
  • Type: Thesis , Masters , MMus
  • Identifier: vital:2659 , http://hdl.handle.net/10962/d1003729
  • Description: Introduction: This portfolio consists of musical ideas which I have had for some time now. I have attempted to capture these ideas throughout the portfolio, starting with the smaller works (Brumes et Pluies) and building up to the larger works (James Tiberius, The tide). Brumes et Pluies is minimalistic in style. The interlocking of the two pianos plays an important role in the texture of the piece. The rhythms are repetitive throughout, with only slight variations. Kalahari is more idiomatic, rhythmical and has a main theme which recurs throughout the piece. Melodic fragments are used, sometimes with slight variations. This piece was inspired by the Kalahari desert, with its abundance of life. I enjoy the string quartet because of the homogeneity of sound on the one hand, and the diversity possible by using different techniques and effects on the other. James Tiberius is a work for chamber orchestra. Motifs in the music resemble certain animals. The rhythm is unstable, as is the harmony. There are many melodic fragments throughout. The texture is thin in certain areas (at the beginning) and dense in others (the waltz). The harmony is sometimes unconventional. The Tide was written in response to a memory of a drowning incident I experienced when I was a child. This orchestral piece is strong in form. The opening, for example, is tense and slightly atonal in harmony. The pomposo section tends to utilise most of the orchestra, so the texture is a lot denser here and the harmony is more conventional. I try not to use traditional forms in my composition. Rather, I prefer to compose by re-using and re-introducing ideas as I proceed.
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  • Date Issued: 2006

Comprehension and acceptability of a patient information leaflet (PIL) for antiretroviral therapy:

  • Authors: Mwingira, Betty , Dowse, Roslind
  • Date: 2006
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/156902 , vital:40065 , https://doi.org/10.4102/hsag.v11i3.236
  • Description: The patient information leaflet (PIL) is recognised as playing a key role in informing patients about their medicines. The objectives of this research were to evaluate the readability and understanding of a PIL for the first-line ARV (antiretroviral) regimen available in the South African public health sector, and investigate its acceptability in the target Xhosa population. The study took place between August 2003 and July 2004. A PIL was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz, using established usability guidelines. South African legal requirements concerning PILs were incorporated and the PILs were available in both English and isiXhosa.
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  • Date Issued: 2006

Confession and public life in post‐apartheid South Africa: A Foucauldian reading of Antjie Krog's country of my skull

  • Authors: Garman, Anthea
  • Date: 2006
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/159724 , vital:40337 , DOI: 10.1080/02564710608530406
  • Description: Truth commissions around the world have given the technique of confession a new public currency and political power. Many works of literature thematising these commissions have also adopted the technique of confession for literary purposes. In this paper I bring Foucault's understanding of the technique of confession, and his discourse on the role of public intellectuals in modernity, to bear upon an examination of Antjie Krog's literary reflection of the work of the Truth and Reconciliation Commission (TRC), entitled Country of My Skull (1998). I look at how this text, and Krog's subsequent public intellectual status as a witness of the TRC, perpetuate the technique of confession without problematising it in ways that Foucault's work would suggest is necessary.
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  • Date Issued: 2006

Contrasting livelihoods in the upper and lower Gariep River basin: a study of livelihood change and household development

  • Authors: McDermott, Lindsay
  • Date: 2006
  • Subjects: Rural development -- Lesotho , Rural development -- South Africa -- Northern Cape , Sustainable development -- Lesotho , Sustainable development -- South Africa -- Northern Cape , Households -- Economic aspects -- Lesotho , Households -- Economic aspects -- South Africa -- Northern Cape , Rural poor -- Lesotho , Rural poor -- South Africa -- Northern Cape , Agriculture -- Lesotho , Agriculture -- South Africa -- Northern Cape
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:4758 , http://hdl.handle.net/10962/d1007147 , Rural development -- Lesotho , Rural development -- South Africa -- Northern Cape , Sustainable development -- Lesotho , Sustainable development -- South Africa -- Northern Cape , Households -- Economic aspects -- Lesotho , Households -- Economic aspects -- South Africa -- Northern Cape , Rural poor -- Lesotho , Rural poor -- South Africa -- Northern Cape , Agriculture -- Lesotho , Agriculture -- South Africa -- Northern Cape
  • Description: This study investigated rural livelihoods in two contrasting environments in the upper and lower reaches of the Gariep River: Sehlabathebe in the Lesotho highlands, and the Richtersveld in the Northern Cape, and how these have changed over time. Livelihoods were examined using the Sustainable Livelihoods Framework in conjunction with the household development cycle. This study therefore adopted a multi-scale approach, where a micro-level household analysis was framed within the macro level social, political, environmental, economic and institutional context, while taking into account the role of temporal scale of livelihood change. A multi-scale approach facilitated the identification of the major drivers of change, both exogenous and endogenous. The combination of livelihood strategies pursued differed between the two sites. Households in Sehlabathebe are reliant mainly on arable and garden cultivation, livestock in some households, occasional remittances, use of wild resources, petty trading and reliance on donations. Households in the Richtersveld relied primarily on livestock, wage labour, use of wild resources and State grants or pensions. The livelihood strategies pursued in each site have not changed markedly over time, but rather the relative importance of those strategies was found to have changed. The assets available to households, the livelihood strategies adopted and the changes in these livelihood strategies are influenced by a households stage in the development cycle and differing macro-level factors. Drivers of change operate at multiple spatial and temporal scales, and are often complex and interrelated. The major drivers of livelihood change were identified as macro-economic, demographic, institutional and social and climatic. This study highlights the importance of using historical analysis in the study of livelihoods, as well as the complexity and diversity of rural livelihoods. Ecosystem goods and services were found to play a fundamental role in rural livelihoods and are influenced by institutional factors. Rural households are heavily reliant on the formal economy, and macro-economic changes have had a significant impact on livelihoods. This is highlighted by how the drastic decline in migrant labour opportunities for households in Sehlabathebe has negatively affected them. Vulnerability was shown to be a result of external shocks and trends, such as institutional transformation, a decline in employment opportunities, theft and climatic variation; and differed between the two sites. The role of institutional breakdown was shown to be a major factor influencing rural livelihoods, and this is related to broader economic and political changes. This study contributes to the growing literature on rural livelihoods by allowing for an appreciation of how differing environments and contextual factors influence livelihood strategies adopted, and which different factors are driving change.
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  • Date Issued: 2006

Converts and conservatives: missionary representations of African rulers in the Northern Transvaal, c. 1870-1900

  • Authors: Kirkaldy, Alan , Kriel, Lize
  • Date: 2006
  • Language: English
  • Type: Article
  • Identifier: vital:6146 , http://hdl.handle.net/10962/d1003715 , http://www2.unil.ch/lefaitmissionnaire/pages/tables_publi/lfm18_tbl.htm
  • Description: During the second half of the nineteenth century, the Berlin Mission Society made strenuous efforts to convert the rulers of the people in whose areas they worked in the Northern Transvaal. In this they were largely unsuccessful. This raises questions about what forces influenced success and failure, and how the missionaries interpreted this. In this article, we interrogate the Berlin Missions Society’s accounts of the life and death of August Makhahane, a ruler of the Vhavenda who converted to Christianity, against the background of the accounts dealing with Matsiokwane Leboho, a ruler of the Bahananwa who did not convert. Through such a comparison, we aim at exploring the contrasted ways in which the Berlin missionaries reported about the two rulers.
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  • Date Issued: 2006

Corporate information risk : an information security governance framework

  • Authors: Posthumus, Shaun Murray
  • Date: 2006
  • Subjects: Computer security , Business enterprises -- Computer networks -- Security measures
  • Language: English
  • Type: Thesis , Masters , MTech
  • Identifier: vital:9776 , http://hdl.handle.net/10948/814 , Computer security , Business enterprises -- Computer networks -- Security measures
  • Description: Information Security is currently viewed from a technical point of view only. Some authors believe that Information Security is a process that involves more than merely Risk Management at the department level, as it is also a strategic and potentially legal issue. Hence, there is a need to elevate the importance of Information Security to a governance level through Information Security Governance and propose a framework to help guide the Board of Directors in their Information Security Governance efforts. IT is a major facilitator of organizational business processes and these processes manipulate and transmit sensitive customer and financial information. IT, which involves major risks, may threaten the security if corporate information assets. Therefore, IT requires attention at board level to ensure that technology-related information risks are within an organization’s accepted risk appetite. However, IT issues are a neglected topic at board level and this could bring about enronesque disasters. Therefore, there is a need for the Board of Directors to direct and control IT-related risks effectively to reduce the potential for Information Security breaches and bring about a stronger system of internal control. The IT Oversight Committee is a proven means of achieving this, and this study further motivates the necessity for such a committee to solidify an organization’s Information Security posture among other IT-related issues.
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  • Date Issued: 2006

Corporate social responsibility: evaluating three South African Companies' initiatives

  • Authors: Fourie, Neil
  • Date: 2006
  • Subjects: Social responsibility of business -- South Africa Case studies , Social responsibility of business -- South Africa
  • Language: English
  • Type: Thesis , Masters , MBA
  • Identifier: vital:8563 , http://hdl.handle.net/10948/568 , Social responsibility of business -- South Africa Case studies , Social responsibility of business -- South Africa
  • Description: The aim of this research project was to evaluate the available theoretical information on Corporate Social Responsibility and with this knowledge to then also evaluate three companieś initiatives based on this information. Gone are the days when an organisation could do business for the sole purpose of making a profit. If the organisation does not take the environment into account in doing business, or if the community where this organisation is situated or does business, feel “abused” or that their needs are not being addressed, the organisation will not survive and its future sustainability can not be assured or guaranteed. This has been proven internationally, but how does South African organisations fare when it comes to corporate social responsibility, and more specifically, what social responsible initiatives are taken? The research also attempted to determine how “industry specific” the three companies'́ initiatives are and whether any changes in initiative-directions should be considered. The Social Responsibility Initiatives of Woolworths, ENGEN and SABMiller (South Africa) were evaluated and certain shortcomings were identified and presented to the various companies. These companies deliver excellent products and services to their client base, but it was felt that should adherence be given to the recommendations that were made, the mentioned companies could in future improve their turnover, market position and increase their client support base. Finally, it could also assist in increasing brand loyalty amongst their customers.
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  • Date Issued: 2006

Creating international support for the development of the news media in Africa

  • Authors: Banda, Fackson
  • Date: 2006
  • Language: English
  • Type: Article
  • Identifier: vital:6326 , http://hdl.handle.net/10962/d1008301
  • Description: This article analyses the issues associated with providing support mechanisms for strengthening media institutions in Africa. It takes a historical look at the involvement of international actors in the evolution of African media, arguing that ideology plays a key role in the way international support is crafted for Africa's development, including media development.
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  • Date Issued: 2006

Creating knowledge networks

  • Authors: Kruss, G , Klerck, Gilton , Paterson, Angus William , Godfrey, S
  • Date: 2006
  • Language: English
  • Type: Text
  • Identifier: vital:544 , http://hdl.handle.net/10962/d1012400
  • Description: The new science and technology framework has challenged higher education institutions in South Africa to create research partnerships with industry, to contribute to growing a national system of innovation. Through detailed case studies, this monograph explores how one new organisational form typical of the knowledge society, the network, is currently being created in practice, in all its complex and contingent reality, in three high technology fields. It is the third volume in the Working Partnerships: Higher Education, Industry and Innovation series. The case studies show that knowledge networks are primarily shaped by the competitive dynamics of the industrial sub-sector within which partner enterprises operate, intersecting with the levels of scientific and managerial expertise within higher education partner institutions, and facilitated by government policy steering mechanisms and intermediary partners. The intersection of interests gives all partners a stake in the research project at the heart of the knowledge network, and builds the levels of trust required to succeed. The analysis highlights some of the possibilities and constraints evident in the current policy context, suggesting that state attempts to steer the system need to be more nuanced and targeted, informed by the specificity of sectoral dynamics, and it suggests that universities need to identify their own strategic solutions to develop a flexible and adaptive institutional approach to networks.
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  • Date Issued: 2006

Critical media literacy: a design for the future

  • Authors: Prinsloo, Jeanne
  • Date: 2006
  • Language: English
  • Type: text , Article
  • Identifier: vital:6331 , http://hdl.handle.net/10962/d1008476
  • Description: [From OPENSPACE Editor Alice Kanengoni's editorial]: Professor Jeanne Prinsloo notes in her article that "In fact, it has been argued that the significance of the media in people’s lives has increased to the extent that it has been described as their primary curriculum, thereby recasting formal education as the secondary curriculum." This therefore requires an incestment in media literacy; people's ability to to understand the world around them, as represented in the media. Thus, Professor Prinsloo argues for critical media literacy, citing the role that the media played in fuelling the genocide in Rwanda, as an illustrative case in point. She states that "While we can not attribute all blame in the Rwandan scenario to the radio use, it is clear that the media mattered." She indicates that "media representations and engagements play a significant role in the way we understand the world, its people and events, and ourselves therein." As such, societies should invest in building a critical citizenry that can read and deconstruct the various ideologies that are often carries in and through the media.
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  • Date Issued: 2006

Cross-cultural differences in IQ test performance: extension of an existing normative database on WAIS-III test performance

  • Authors: Gaylard, Emma K
  • Date: 2006
  • Subjects: Wechsler Adult Intelligence Scale , Wechsler Adult Intelligence Scale -- South Africa , Black people -- Education , Black people -- Social conditions , Intelligence tests -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2979 , http://hdl.handle.net/10962/d1002488 , Wechsler Adult Intelligence Scale , Wechsler Adult Intelligence Scale -- South Africa , Black people -- Education , Black people -- Social conditions , Intelligence tests -- South Africa
  • Description: Prior research (Shuttleworth-Edwards et al., 2004) presented preliminary normative data for the Wechsler Adult Intelligence Scale – III (WAIS-III) for Southern Africa, stratified according to gender (female vs. male), language (black African vs. white English), level of education (matric/12+ years of education vs. Graduate/15+ years of education) and quality of education (disadvantaged – Department of Education and Training vs. advantaged - Private/Model C). IQ scores for black African language and white English Southern Africans were comparable with the United States of America (USA) standardization when level and quality of education were equitable. (‘White English’ is the term used to denote those of European descent whose first language is English). A limitation of the research was the lack of control for language for most of the black groups and particularly in the Private/Model C Graduate group, where sixty percent of the participants originated from Zimbabwe. These represented a particularly elite group whose education was equitable to that of the white participants throughout their education (i.e. at primary, secondary and tertiary level). In order to rectify the lack of homogeneity of language, all non- Xhosa first language participants were excluded from the black sample and sixteen additional Xhosa first language participants were tested on the WAIS-III. Data analyses found no significant differences between the original and new groups, except in the comparison between Mixed African language Private/Model C Graduates and the Xhosa first language Private/Model C Graduate/15+ years of education, where there was a lowering of WAIS-III subtest, index and IQ scores in the newly constituted group. This lowering in test performance is explained in that the new Xhosa first language 15+ years of education group was a less advantaged group than the original Mixed African Language Private/Model C Graduate group, as the new group generally had less advantaged primary school education and had generally studied less at a tertiary level. Overall, these results demonstrate an incremental increase in WAIS-III test performance for sample groups on a continuum of quality of education from least to most advantaged education. This was true for both verbal and non-verbal subtests.
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  • Date Issued: 2006

Cultural significance of biodiversity: the role of medicinal plants in urban African cultural practices in the Eastern Cape, South Africa

  • Authors: Cocks, Michelle L , Dold, Anthony P
  • Date: 2006
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/141338 , vital:37963 , DOI: 10.2993/0278-0771(2006)26[60:CSOBTR]2.0.CO;2
  • Description: Since the International Convention on Biodiversity in 1992 conservation biologists, ecologists and conservationists have devoted considerable attention to the conservation of biodiversity. With this has come the realization that solutions to biological problems often lie in the mechanisms of social, cultural, and economic systems. This shift has emphasized the relationship between biodiversity and human diversity, or what the Declaration of Belem (1988) calls an “inextricable link” between biological and cultural diversity. The term biocultural diversity was introduced by Posey to describe the concept denoting this link. To date this concept has been used only in reference to “indigenous people” who, as part of their traditional lifestyles, use biodiversity to sustain their cultural identity. Our research, however, demonstrates that Xhosa people (amaXhosa) living in an urban context in the Eastern Cape Province of South Africa continue to use wild plants for cultural purposes and often access these through commercial trade. We suggest that recognition of the cultural and spiritual values associated with wild plants would greatly enhance biodiversity conservation efforts. Recognition of the significant role that wild plants play in fulfilling cultural needs for urban Xhosa people would go a long way towards achieving this.
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  • Date Issued: 2006

Cytokine signalling functions of human soluble IgE receptors in peripheral blood mononuclear cells from normal and hyper-allergic individuals and in B-lymphoblastoid and monocytic cell lines

  • Authors: Askew, Sandra Lyn
  • Date: 2006
  • Subjects: Ligands , Cell receptors , Cellular signal transduction
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:10305 , http://hdl.handle.net/10948/455 , Ligands , Cell receptors , Cellular signal transduction
  • Description: CD23 is a multifunctional receptor/ligand, found in a variety of cell types, such as human peripheral blood mononuclear cells (PBMCs), B-lymphoblastoid cell lines, mast cells and basophils. It is also found on a variety of haematopoietic cell lines. As the low-affinity receptor for immunoglobulin E (IgE), CD23 plays a role in antigen-presentation and macrophage activation. As a surface molecule cleaved from the cell membrane, soluble CD23 (sCD23) can act as an adhesion molecule and a cytokine. Perturbances of such molecular interactions may lead to various diseases such as allergies and other inflammatory diseases. It has been speculated that elevated levels of sCD23 may be used to bind secreted IgE, thus preventing it from binding to membrane CD23 on haematopoietic cells, preventing B cells from being activated into IgE producing cells. Signal transduction by sCD23 is dependent on cell subsets, ligands and co-factors required for its function. sCD23 plays a direct role in inducing tumour necrosis factor alpha (TNFα), interleukin-1 alpha (IL-1α) and interleukin-1 beta (IL-1β) and soluble IL-1 receptor from activated human monocytes and PBMCs in vitro. Recombinant forms of 25 and 37 kDa human sCD23 were produced by polymerase chain reaction (PCR)-cloning into pET23a, a bacterial expression vector. The proteins were expressed and refolded, followed by purification by gel filtration chromatography. The purified proteins were biochemically characterized to ensure purity and biological activity, by observing the binding to human IgE both in enzyme-linked immunosorbant assay (ELISA) and surface plasmon resonance (SPR) spectroscopy. ELISA showed KD values of 7.23 x 10-9M and 8.12 x 10-9M for the 25 and 37 kDa proteins, respectively. These values were significantly lower than that of Hibbert et al., (2005). SPR data obtained for the 25 kDa CD23 was not of reliable quality but SPR for the 33kDa sCD23 showed a KD of 1.18 x 10-7M, close to that of Hibbert et al., (2005), J. Exp. Med, 202: 751-760. To test the therapeutic potential of the recombinant molecule, a B-lymphoblastoid cell line (Raji), a pre-monocytic cell line (U937), and PBMCs from normal and hyper-allergic individuals were used. All cells showed no change in production of cytokines. It is essential to investigate further cytokine functions and production implicated by recombinant forms of sCD23, as well as binding of sCD23 to CD21 and CD11b/c, and in vivo IgE regulation before a conclusion can be drawn as to whether recombinant sCD23 is a potential therapeutic target against allergic disease.
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  • Date Issued: 2006

Decorating Asterisk : experiments in service creation for a multi-protocol telephony environment using open source tools

  • Authors: Hitchcock, Jonathan
  • Date: 2006
  • Subjects: Asterisk (Computer file) , Internet telephony
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4635 , http://hdl.handle.net/10962/d1006539 , Asterisk (Computer file) , Internet telephony
  • Description: As Voice over IP becomes more prevalent, value-adds to the service will become ubiquitous. Voice over IP (VoIP) is no longer a single service application, but an array of marketable services of increasing depth, which are moving into the non-desktop market. In addition, as the range of devices being generally used increases, it will become necessary for all services, including VoIP services, to be accessible from multiple platforms and through varied interfaces. With the recent introduction and growth of the open source software PBX system named Asterisk, the possibility of achieving these goals has become more concrete. In addition to Asterisk, a number of open source systems are being developed which facilitate the development of systems that interoperate over a wide variety of platforms and through multiple interfaces. This thesis investigates Asterisk in terms of its viability to provide the depth of services that will be required in a VoIP environment, as well as a number of other open source systems in terms of what they can offer such a system. In addition, it investigates whether these services can be made available on different devices. Using various systems built as a proof-of-concept, this thesis shows that Asterisk, in conjunction with various other open source projects, such as the Twisted framework provides a concrete tool which can be used to realise flexible and protocol independent telephony solutions for a small to medium enterprise.
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  • Date Issued: 2006

Democracy in Lesotho: theory and practice of opposition

  • Authors: Mohapi, Refiloe Alphonce
  • Date: 2006
  • Subjects: Democracy -- Lesotho , Political parties -- Lesotho , Lesotho -- Politics and government
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2806 , http://hdl.handle.net/10962/d1003016 , Democracy -- Lesotho , Political parties -- Lesotho , Lesotho -- Politics and government
  • Description: Using theoretical insights from elsewhere, this thesis examines and explains Lesotho’s opposition. It argues that the decline of single-member constituency and the rise of Mixed Member Proportionality (MMP) has weakened the prospects for a strong opposition in Lesotho; more parties in parliament have strengthened the hold of the ruling party. These parties cannot overturn the parliamentary decisions of the ruling Lesotho Congress for Democracy (LCD), which continues to win more than 90% of majority seats in successive elections. So, most bills and motions passed in parliament have support of the majority of the MPs of LCD. Opposition parties have little legislative impact in challenging the policies of government. Paradoxically, MPs of the LCD are often the only source of opposition in the country’s parliament.
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  • Date Issued: 2006
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