Narratiewe strategieë by die ondersoek van die verlede in twee romans, naamlik Lijken op liefde (1997) deur Astrid H. Roemer en Duiwelskloof (1998) deur André P. Brink
- Authors: Potgieter, Maretha
- Date: 2002
- Subjects: Roemer, Astrid. Lijken op liefde , Brink, André Philippus, 1935- Duiwelskloof
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3578 , http://hdl.handle.net/10962/d1002151 , Roemer, Astrid. Lijken op liefde , Brink, André Philippus, 1935- Duiwelskloof
- Description: This study investigates some of the narrative strategies used by two novels, namely Lijken op Liefde (1997) by the Surinam born author Astrid H. Roemer and Duiwelskloof (1998) by the South African André P. Brink, in their exploration of and dialogue with traumatic pasts. Both texts are written within so-called postcolonial time frames, delve into the personal and collective past and attempt to provide a corrective on knowledges that used to be deemed not useful, unimportant or have been forgotten by official historiography. The theoretical base of the study is an eclectic mixture of both postcolonial and postmodern theories, throwing light on the strategies employed by these novels in order to understand, problematise and creatively exploit the past. , Hierdie studie kyk na sommige van die narratiewe strategieë binne twee romans, naamlik Lijken op Liefde (1997) deur die Surinaams-gebore outeur Astrid H. Roemer en Duiwelskloof (1998) deur die Suid-Afrikaner André P. Brink, in hulle ondersoek na en dialoog met die traumatiese verlede. Beide tekste is geskryf binne sogenaamde postkoloniale tydvakke, delf in die persoonlike en kollektiewe verlede, en verskaf ’n korrektief op die dinge wat as onbruikbaar of onbelangrik beskou is, of vergete geraak het binne die offisiële historiografie. Die teoretiese basis van die studie is ’n eklektiese mengsel van beide postkoloniale en postmoderne teorieë wat lig werp op die strategieë wat hierdie tekste gebruik om die verlede te verstaan, te problematiseer en kreatief te ontgin.
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- Date Issued: 2002
Heterologous expression of the helicoverpa armigera stunt virus in Saccharomyces cerevisiae
- Authors: Venter, Philip Arno
- Date: 2002
- Subjects: Helicoverpa armigera Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3895 , http://hdl.handle.net/10962/d1003811
- Description: Lepidopteran insects like Helicoverpa armigera, more commonly known as the cotton bollworm, are economically important pests of a wide variety of crops throughout the world. The Helicoverpa armigera stunt virus (HaSV), a tetravirus with a bipartite single-stranded positive-sense RNA genome, has great potential as a biological pesticide against H. armigera. The larger genomic strand of this virus (RNA1) encodes the viral replicase, while the other (RNA2) encodes the 71 kDa capsid protein precursor (p71). 240 copies of p71 assemble into a procapsid with the concomitant encapsidation of the viral RNA. This is followed by a complex maturation event that is characterized by the autoproteolytic cleavage of p71 into the 64 kDa capsid protein (P64) and a 7 kDa peptide (p7). The rearrangements that occur during maturation results in the formation of mature HaSV capsids that can thereupon deliver RNA to other susceptible host cells. The principal objective of the research described in this study was to demonstrate that this virus could be assembled in Saccharomyces cerevisiae. S. cerevisiae expression vectors were constructed for the production of p71. This protein was detected in cell lysates from two different strains of S. cerevisiae, both containing either chromosomal or episomal copies of an expression cassette for P71. A number of factors relating to the expression of P71 (e.g. strains used, expression loci and expression rate) and the preparation of protein extracts from S. cerevisiae (e.g. the presence of various protease inhibitors and salt concentrations) were examined to attain optimal levels of soluble p71. A small fraction of the optimized soluble p71 was shown to be in the form of virus-like particles (VLPs), with a yield of ≤10⁷ VLPs from a 1.5l culture of P71⁺ cells. These particles were exclusively in the procapsid form, had a similar buoyant density to that of wild-type HaSV and could undergo maturation when the pH was reduced to 5. S. cerevisiae vectors were constructed for the episomal expression of the HaSV genomic RNAs. These vectors directed the transcription of RNA1 and RNA2 transcripts, which had similar sizes to those of the HaSV genomic RNAs. Mature HaSV particles were purified from cells, transgenic for P71, RNA1 and RNA2, by way of two different virus purification protocols that were developed during this study. RT-PCR analyses on RNA-extracts from these particles demonstrated that RNA transcripts, which were produced in trans with p71, could be encapsidated by HaSV capsids in S. cerevisiae. A droplet-feed bioassay on H. armigera larvae demonstrated that the S. cerevisiae-derived HaSV particles caused impaired larval development. This response was correlated with the detection of HaSV RNA2 in RNA extractions from larvae that were used in this bioassay. The results that were generated through the course of this study, provided proof for the concept of the non-host production of infectious HaSV particles from S. cerevisiae. This work could serve as a foundation for future research on the development of an expression system for the large-scale production of this virus as a biopesticide.
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- Date Issued: 2002
Metabolic responses to various combinations of gradient, load and marching speed
- Authors: Todd, Andrew I , Scott, Patricia A
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6751 , http://hdl.handle.net/10962/d1009331
- Description: This study examined the metabolic cost of South African soldiers carrying loads under various conditions of gradient and marching speed. Thirty-two male soldiers participated in the study. Three speed and load combinations, 4, 5 and 6 km.h[superscript (-1)] carrying of 50, 35 and 20 kg respectively, were imposed, on each of three gradients: -10%, 0% and +10%; a total of nine experimental conditions. Subjects wore standardized military uniforms and breathed into a portable ergospirometer (Metamax) for the duration of each condition. Subjects were required to march for six minutes under each condition, and metabolic responses were monitored during the third and sixth minute of each condition. The metabolic responses to the three level marching conditions showed no significant differences. Marching uphill resulted in a significant increase in metabolic demands under all three speed and load onditions. Downhill marching elicited significant decreases only under the two lighter load conditions. Downhill marching with heavy loads appears to show no reduction in metabolic demands placed on soldiers.
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- Date Issued: 2002
The land question in South Africa, Zimbabwe and Kenya: a geographical perspective on resource endowment
- Authors: Fox, Roddy C , Rowntree, Kate M
- Date: 2002
- Language: English
- Type: Conference paper
- Identifier: vital:6664 , http://hdl.handle.net/10962/d1006671
- Description: In sharp contrast to the debates concerning land policy, land tenure and sustainable resource management in South Africa is any input concerning the geographical distribution of land productivity. This paper attempts to redress this imbalance by providing an empirical investigation of land potential in South Africa. In this way we intend to provide the crucial context for policy and academic studies of the land issue in South Africa. Furthermore, we will undertake our study in such a way that comparison can be made to Zimbabwe and Kenya where the land issue has been such a critical component of the post-colonial development process. Theoretically our work is contextualised within the debates surrounding the importance of geographical endowments, institutions and policies in the development process.
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- Date Issued: 2002
Gender discourse and Malawian rural communities: a study of the meaning the people of traditional authority Likoswe of Chiradzulo make from human rights and gender messages
- Authors: Manda, Levi Zeleza
- Date: 2002
- Subjects: Human rights -- Malawi , Mass media in community development -- Malawi , Communication in community development -- Malawi , Mass media -- Social aspects -- Malawi , Mass media criticism -- Malawi , Women's rights -- Malawi , Sex role -- Malawi
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3456 , http://hdl.handle.net/10962/d1002910 , Human rights -- Malawi , Mass media in community development -- Malawi , Communication in community development -- Malawi , Mass media -- Social aspects -- Malawi , Mass media criticism -- Malawi , Women's rights -- Malawi , Sex role -- Malawi
- Description: Contrary to earlier beliefs and media theories such as the hypodermic needle or magic bullet, the audience of public communication is not a passive homogenous mass that easily succumbs to media influence. The audience is active, that is, it makes an effort to interpret media content. Depending on predisposing cultural, political, religious, or economic factors the audience makes different meanings from media texts. Media messages are not wholly controlled by producers, although the producers have their preferred and expected readings. Using qualitative research techniques associated with ethnographic and cultural studies (notably focus group discussions), this study sought to explore the meanings rural people in Malawi make out of human rights and gender messages broadcast on radio and through music. Interpreted against Stuart Hall's (1974b) Encoding and Decoding model, the study concludes that while rural communities understand and appreciate the new sociopolitical discourse, they take a negotiated stance because they have their own doubts and fears. They fear losing their cultural identity. Additionally, men, in particular, negotiate the messages because they fear losing their social power over land, property and family.
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- Date Issued: 2002
Reading William Blake and T.S. Eliot: contrary poets, progressive vision
- Authors: Rayneard, Max James Anthony
- Date: 2002
- Subjects: Blake, William, 1757-1827 -- Criticism and interpretation , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2279 , http://hdl.handle.net/10962/d1007545 , Blake, William, 1757-1827 -- Criticism and interpretation , Eliot, T. S. (Thomas Stearns), 1888-1965 -- Criticism and interpretation
- Description: Many critics resort to explaining readers' experiences of poems like William Blake's Jerusalem and T.S. Eliot's Four Quartets in terms of "spirituality" or "religion". These experiences are broadly defined in this thesis as jouissance (after Roland Barthes' essay The Pleasure of the Text) or "experience qua experience". Critical attempts at the reduction of jouissance into abstract constructs serve merely as stopgap measures by which critics might avoid having to account for the limits of their own rational discourse. These poems, in particular, are deliberately structured to preserve the reader's experience of the poem from reduction to any particular meta-discursive construct, including "the spiritual". Through a broad application of Rezeption-Asthetik principles, this thesis demonstrates how the poems are structured to direct readers' faculties to engage with the hypothetical realm within which jouissance occurs, beyond the rationally abstractable. T.S. Eliot's poetic oeuvre appears to chart his growing confidence in non-rational, pre-critical faculties. Through "The Love Song of J. Alfred Prufrock", The Waste Land, and Four Quartets, Eliot's poetry becomes gradually less prescriptive of the terms to which the experience of his poetry might be reduced. In Four Quartets he finally entrusts readers with a great deal of responsibility for "co-creating" the poem's significance. Like T.S . Eliot, although more consistently throughout his oeuvre, William Blake is similarly concerned with the validation of the reader's subjective interpretative/creative faculties. Blake's Jerusalem is carefully structured on various intertwined levels to rouse and exercise in the reader what the poet calls the "All Glorious Imagination" (Keynes 1972: 679). The jouissance of Jerusalem or Four Quartets is located in the reader's efforts to co-create the significance of the poems. It is only during a direct engagement with this process, rather than in subsequent attempts to abstract it, that the "experience qua experience" may be understood.
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- Date Issued: 2002
Selecting an appropriate process for the formulating of an operations strategy for Bridgestone/Firestone, Port Elizabeth plant, in a changed market environment
- Authors: Jeena, Umesh
- Date: 2002
- Subjects: Tire industry -- South Africa -- Port Elizabeth -- Management , Bridgestone/Firestone (Firm)
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10945 , http://hdl.handle.net/10948/d1011325 , Tire industry -- South Africa -- Port Elizabeth -- Management , Bridgestone/Firestone (Firm)
- Description: The research problem addressed in this study was aimed in assisting the management of Bridgestone/Firestone, Port Elizabeth plant, in selecting an appropriate process for the formulation of an operations strategy. The author embarked on a literature survey to gain understanding of the challenges that are occurring in the market environment. The theories and techniques around operational strategies were extensively researched in an effort to effectively and efficiently assist the management of Firestone in achieving a competitive advantage over rival competitors. Other areas of focus include the content, development, principles and concepts in developing an operations strategy. The author details the process of the formulation of an operations strategy as well as the discussion of four models/procedures deployed in organisations that would enhance strategy formulation. It is evident from the findings of the empirical study that a high percentage of the respondents “agree” that the strategy deployed within Bridgestone/Firestone, Port Elizabeth plant is appropriate, yet an alarmingly high percentage believe it to be “ineffective.
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- Date Issued: 2002
Evaluation of manufacturing processes for the production of atrazine
- Authors: Schaefer, Melissa Claire
- Date: 2002
- Subjects: Atrazine , Pesticides
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10960 , http://hdl.handle.net/10948/96 , Atrazine , Pesticides
- Description: This report describes the results of investigations carried out with the view to find an alternative for MIBK as solvent for the production of atrazine as currently practised by Dow AgroSciences in South Africa. The main motivating factors for the said investigation was: · to increase the yield of atrazine produced, · to reduce the amount of organics, consisting essentially of reaction solvent containing dissolved product, in the aqueous process effluent, and · to improve the properties of the solid (crystalline) product to enable easier product formulation. Synthetic reactions carried out in the absence of organic solvent, i.e. in essentially a 10% NaCl solution containing a surfactant, proved rather disappointing. Low yields of atrazine were obtained together with relatively large amounts of by-products such as propazine and simazine, irrespective of the nature of the surfactant. The reason for the low yield of atrazine and high yields of by-products were established in competing substitution reactions. In these reactions, IPA was reacted with an equimolar mixture of cyanuric chloride and mono-i (first reaction intermediate) in both aqueous medium and in toluene as reaction solvent. The results of these experiments indicated that in aqueous medium IPA reacts faster with mono-i than cyanuric chloride to give propazine as by-product. In toluene, however, the preferred reaction is with cyanuric chloride to give more mono-i as product. Toluene was investigated as an alternative organic solvent to MIBK in view of its desirable properties such as low solubility in water and ease of recovery and recycling. The synthesis of atrazine was optimised in terms of addition sequence and rates of amine reagents and base (HCl acceptor), both by means of benchscale reactions and reaction calorimetry. Reaction energy profiles indicated that both the reaction of secondary amine/NaOH and primary amine/NaOH were virtually instantaneous. This implies that the reaction can be performed under feed control conditions. Of particular importance in ensuring high yields of high purity product was accurate temperature control (since both reaction steps are highly exothermic) and mixing. The latter was important in view of the rapid reaction of amine/NaOH with cyanuric chloride, as well as the possible reaction of mono-i, the first reaction intermediate, with IPA in cases of local excesses of reagent. Under optimum conditions, a yield of atrazine > 97% could be achieved where the resultant product was well within stipulated product specifications. In view of the results obtained, the following recommendations regarding the synthesis of atrazine in toluene as reaction solvent can be made: · Use a reagent addition sequence that staggers the addition of amine and NaOH in such a manner that amine is added first for a short while, followed by the simultaneous addition of amine and NaOH, and ending with NaOH. Use two reaction vessels in series, one for the IPA addition reaction and one for the MEA addition reaction. In this manner the reaction can be run on a continuous basis since no lag time between amine additions is required. Also, smaller reactors may be used whilst maintaining high production rates. Smaller reactors will improve both temperature control and mixing of reagents.
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- Date Issued: 2002
Science for all - myth or reality?: a research project
- Authors: Valiathazhel, James Daniel
- Date: 2002
- Subjects: Science -- Study and teaching -- South Africa Motion -- Study and teaching -- South Africa Physics -- Study and teaching -- South Africa Competency-based education -- South Africa Educational change -- South Africa Technical institutes -- South Africa Technical education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1847 , http://hdl.handle.net/10962/d1004391
- Description: Abstract: Transformation at a historically disadvantaged technikon in South Africa : a research project: South Africa is in the seventh year of democracy. During the first term of office, the ANC government proposed radical shift from the system(s) of education that was/were in existence in this country. A change in the education system in South Africa was inevitable. The ANC government have realised the need and proposed plans for a change in the education system in this country. We might be able to overcome the inequalities of the past and have an education system relevant for all South Africans that promote an equal opportunity for success as envisaged by Outcomes Based Education (OBE). This research project, using a qualitative case study methodology, reports on the readiness of Border Technikon in implementing Outcomes Based Education (OBE) as a teaching/lecturing strategy. Since 1998 Border Technikon organised a series of staff training workshops to empower the academic staff in Outcomes Based Education. A preliminary study on the topic was conducted during 1999, in which questionnaires (to 16 academic staff) and semi-structured interviews (with three academic staff) were used to collect data. During 2000, when the second and final round of this study was conducted semistructured interviews were employed with 4 staff members to gather data. Literature review and document analysis was also part of the research. The analysis of data indicated that the very nature of most of the Technikon Programmes demands an OBE approach in teaching/lecturing and hence OBE based teaching/lecturing is largely practised at Border Technikon. However a few areas of concerns were identified. Some of these concerns were: (i) Technikon employed academic staff (from industry, etc...) with no professional qualification in teaching and it was difficult to provide OBE training to such people and (ii) lack of sufficient support from the Technikon Management might be a cause for the poor attendance of academic staff during the training programme. Another aspect emerged from the data analysis was that all academic staff participated in this study expressed the need for further training in OBE and related topics. Abstract: Science for all - myth or reality?: Different educational projects around the world have made Scientific Literacy a world-wide concern. This study through a literature review shows that Scientific Literacy is a term that has many definitions and interpretations. This literature review reveals that, in the present system Science for All is a myth for various reasons. Governments around the world in general, and South Africa in particular, are in the process of introducing different projects such as the Year of Science and Technology (YEAST), science week and science exhibitions for the purpose of popularising science and technology. The Department of Education in Thailand has modified its education system to accommodate Science for All. In this literature review among other issues the status quo in South African science education and the Thailand model were examined. A few recommendations to achieve Science for All are also included in this project. Abstract: Developing and evaluating the use of learning material in science - a constructivist approach towards learning Newton's laws : a research project: The Government of National Unity in 1994 introduced a new educational policy for South Africa. This represented a shift in paradigm from a transmission mode of teaching and learning to a learner-centred education. The shift marks a transformation from a content-based curriculum to an Outcomes Based Education (OBE). Various authors found that different sections in the Physical Science syllabus in South Africa are often misunderstood by students for different reasons. One of the reasons was that students had their own ideas about laws of nature and these (mis)conceptions were resistant to change. From the literature and from the author's personal experience it was found that Bodies in Motion is a topic that is difficult to conceptualise by students of different age groups. The challenge facing educators is how to tackle this issue. In this research project a diagnostic test is developed and used to identify the topics where students have conceptual problems. To address these problem areas further, concept sheets/work sheets where developed and implemented. The different challenges and tasks given in the work sheets/learning material are organised in such a way as to make the students aware of their own ideas about Bodies in Motion in general and the key-concepts in particular and also to make them aware of the ideas of their peers (group members). It was also aimed at offering the learners the scientific alternative to their own beliefs. At the end, it was discovered that, even though the general understanding of the learners has improved in this topic (namely, Bodies in Motion), their original beliefs were largely unaffected. It is the hope of the researcher that the project would be the basis for further research on the development of learning material in science.
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- Date Issued: 2002
Workplace Reorganisation Course
- Authors: DITSELA
- Date: 2002
- Subjects: Development Institute for Training,Support and Education for Labour (DITSELA)
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/175688 , vital:42606
- Description: This booklet is about the way in which work is being restructured in the workplaces of South Africa. It is the first in a series of booklets dealing with various restructuring issues faced by workers. There are major changes being made in the workplace that impact on the lives of workers. For workers, restructuring brings changes to the way that their workplace is organised and this will impact on their working lives. These changes could hold threats or opportunities for workers. This first book will explain what is meant by restructuring and look at why many companies in South Africa are considering restructuring. It will also look at some trade union strategies around restructuring and some suggestions for negotiating restructuring.
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- Date Issued: 2002
The ecophysiology of selected coastal dune pioneer plants of the Eastern Cape
- Authors: Ripley, B S
- Date: 2002
- Subjects: Sand dune plants -- South Africa -- Eastern Cape Sand dune ecology -- South Africa -- Eastern Cape Sand dune plants -- Ecophysiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4222 , http://hdl.handle.net/10962/d1003791
- Description: Understanding the mechanisms and adaptations that allow only certain species to thrive in the potentially stressful foredune environment requires a knowledge of the basic ecophysiology of foredune species. Ecophysiological measurements were conducted on the foredune pioneer species Arctotheca populifolia (Berg.) Norl., Ipomoea pes-caprae(L.) R. Br. and Scaevola plumieri (L.) Vahl. and showed significant differences among species with respect to the physiology associated with biomass production, water and nutrient relations. Differences related to CO₂ assimilation included differences in photosynthetic and respiratory rates, susceptibility to light stress and leaf and stem non-structural carbohydrate concentrations. These resulted in differences in primary production rates of shoots. Mechanisms leading to the differences in CO₂ assimilation among species included differences in stomatal behaviour, carboxylation efficiencies, efficiencies of utilisation of incident photosynthetic photon flux density (PPFD) and rates of ribulose-1,6-bisphosphate (RuBP) regeneration. Correlated with differences in photosynthetic capacity were differences in chlorophyll contents but not differences in leaf nitrogen content. Differences in interspecific stomatal behaviour resulted in significantly different transpiration rates which in combination with differences in assimilation rates resulted in differences in water-use efficiency. The absolute amounts of water transpired, although significantly different among species, were moderate to high in comparison with species from other ecosystems and were typical of mesophytes. Transpiration rates in combination with plant hydraulic conductances and soil water availability resulted in leaf water potentials that were not very negative and none of the investigated species showed evidence of osmotic adjustment. The volume of water transpired by each of the species per unit land surface area was estimated from the relationship between abiotic factors and plant water loss. These relationships varied among species and had varying degrees of predictability as a result of differences in stomatal behaviour between the three species. The water requirements of A. populifolia and S. plumieri were adequately met by the water supplied by rainfall and the water stored in the dune sands. It was therefore not necessary to invoke the utilisation of ground water or the process of internal dew formation to supply sufficient water to meet the requirements. However, I. pes-caprae despite its lower transpiration rates and due to its higher biomass, lost greater volumes of water per unit dune surface area than either A. populifolia or S. plumieri. This resulted in periods of potential water limitation for I. pes-caprae. Incident light was the most important determinant of leaf photosynthetic CO₂ assimilation and transpiration, particularly as a linear relationship between incident PPFD and atmospheric vapour pressure deficit (VPD) could be demonstrated. Whole plant photosynthetic production by S. plumieri was shown to be light limited as a result of mutual shading despite high incident and reflected PPFD occurring in the foredune environment. The leaf hair-layer of A. populifolia was shown to be important in reducing transmitted UV and hence reducing photoinhibition but it also caused reduced transpiration rates because of the thicker boundary layer and thus increased leaf temperatures. The nutrient content of above-ground plant parts of the investigated species were typical of higher plants despite the low nutrient content measured for the dune soils. With the possible exception of nitrogen the nutrient demand created by above-ground production was adequately met by the supply of nutrients either from sand-water or from aquifer-water transpired by the plants. Differences in the volumes of water transpired, and hence the quantity of nutrients potentially taken up via the transpiration stream, resulted in interspecific differences in above-ground plant macronutrient content. The reallocation patterns of nutrients differed both between the various nutrients measured and interspecifically. Standing biomass and the density of plants per unit land area was low in comparison to that of other ecosystems and was different among investigated species. This may be important in maintaining the adequate supply of resources (water, nutrients and light). As a result of the interspecific differences in biomass when production was expressed per unit land surface area the resultant productivity was not dissimilar among species. Productivity was high when comparisons were made with species from other ecosystems. No single resource (water, nutrients or light) could be identified as the controlling factor in the foredune environment and a combination of both resource stress and environmental disturbance are likely to be involved. Physiology, production, growth and growth characteristics conveyed certain adaptive advantages to these species in respect to both resource stress and environmental disturbance. Interspecific differences in these adaptations can be used to offer explanations for the observed microhabitat preferences of the three investigated species. Furthermore features common to all three species offer some explanations as to why these species and not others are able to inhabit the foredunes.
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- Date Issued: 2002
An investigation into the possible neuroprotective role of antidepressant drugs
- Authors: Steiner, Claire
- Date: 2002
- Subjects: Antidepressants -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3792 , http://hdl.handle.net/10962/d1003270 , Antidepressants -- Research
- Description: Antidepressants are widely used in the treatment of depressive illnesses associated with neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease and Huntington’s disease. Neuroprotection in such disorders is of vital importance in order to delay the progression of the primary disorder. The pathology of neurodegeneration is not fully understood. It is however widely accepted that oxidative stress and excitotoxicity play a major role. Brain tissue is rich in phospholipids, which are especially prone to oxidation due to the high level of oxygen utilization in the brain. In addition, the brain lacks defence mechanisms to protect it against the wrath of free radicals. Presently, there is a wide variety of antidepressant drugs available. These range from the original tricyclic antidepressants to the newer selective serotonin reuptake inhibitors. It is not known whether antidepressant drugs, old or new, offer neuroprotection or how the existing state and/or the progression of neurodegeneration, is influenced by these agents. The present study was undertaken to determine how nortriptyline, trimipramine and fluoxetine affect neurodegeneration. Initial in vitro and in vivo studies show that all three of the antidepressants (0-1mM) studied provide neuroprotection from quinolinic acid induced lipid peroxidation. A histological investigation supported these findings by showing that a marginal degree of neuroprotection is apparent when treating animals with antidepressants (10mg/kg) before and following quinolinic acid intrastriatal injection. Further studies were undertaken in an attempt to determine the mode of neuroprotective action of the agents studied. An in vitro study of superoxide anion induced lipid peroxidation indicates that these agents do not act as antioxidants. The influence of the antidepressants on tryptophan 2,3-dioxygenase activity was assessed, based on the understanding that inhibition of this enzyme results in increased levels of the known antioxidant indoleamine, melatonin. Nortriptyline hydrochloride is seen to inhibit tryptophan 2,3-dioxygenase activity and as such it is possible that this antidepressant can indirectly provide neuroprotection by increasing available melatonin. Electrochemical and UV/visible studies show that trimipramine maleate interacts with free iron (II) and iron (III) ions. Free metal ions can catalyse the formation of damaging free radicals. Through interaction with trimipramine maleate, these ions will be unavailable to the system and thus cannot contribute to oxidative stress. The findings of this study indicate that antidepressants may be able to provide neuroprotection to neuronal cells. The mode of such neuroprotective actions need to be further examined so that patients suffering from depression coexisting with neurodegenerative diseases can be safely and effectively treated.
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- Date Issued: 2002
State or public service broadcasting?: an analysis of the coverage of political issues and debates during an election campaign on television news
- Authors: Macha, Herbert
- Date: 2002
- Subjects: Public service television programs -- Zambia , Television in politics , Television broadcasting of news -- Zambia , Elections -- Zambia
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3502 , http://hdl.handle.net/10962/d1006234 , Public service television programs -- Zambia , Television in politics , Television broadcasting of news -- Zambia , Elections -- Zambia
- Description: Public Service Television remains a key institution of democratisation in the context of emerging democracies in Africa, especially with the advent of liberalisation and commercialisation of the media. The democratic changes taking place in Zambia require a genuine public service broadcasting television that will promote pluralism in the public sphere. Among the many available strategies and mechanisms for fostering a sustainable democratic and cultural environment, public service broadcasting is still the best. This study set out to examine representation of political issues and debates during election campaign on ZNBC television news to assess the extent to which it plays a role as a public broadcaster in the mediation of pluralistic politics. Election news on television, in line with the public sphere argument was found to be essential for investigating the nature of public service television from the point of view of impartiality, universality and diversity. Using both qualitative and quantitative methods the study has confirmed the hypothesis that the role of a public service television in the mediation of pluralistic politics is compromised by ZNBC's partial and unbalanced coverage of elections. As a result ZNBC, as a public service broadcaster is undermining the very democracy it is expected to promote. Public service television should take new forms if it is to be recognised and appreciated by the public as a genuine, open and democratic public sphere. I therefore recommend that a system of license fee for viewers be introduced. Secondly, government should increase funding into public service television to supplement revenue from license fee and advertising. Thirdly, I recommend the appointment of an independent board whose members will be appointed for a fixed term, by public nomination and a process of public hearing, according to publicly available criteria, which guarantees diversity of political, ethnic, social and professional background. Fourthly I suggest the formation of an Election News Coverage Committee comprising of journalists, academicians, the church and civic organisation that will formulate and implement editorial policy on election coverage and above all monitor and the coverage of elections on ZNBC television news.
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- Date Issued: 2002