Showing items 161 - 180 of 185

Your selections:

The investigation of the hydrolysis reaction of m-phenylene to resorcinol

  • Authors: Khaile, Thebeeapelo John
  • Date: 2002
  • Subjects: Resorcinol
  • Language: English
  • Type: Thesis , Masters , MTech (Chemistry)
  • Identifier: vital:10961 , http://hdl.handle.net/10948/107 , Resorcinol
  • Description: The purpose of this study was to characterise the resinous material formed during the acid catalysed hydrolysis of m-phenylenediamine (MPDA) to resorcinol, and to establish a reaction mechanism that could explain the formation of both resorcinol and the resinous materials in the reaction. A further objective was to determine reaction conditions that would lead to reduced formation of the resins during the hydrolysis reaction. The number of compounds present in a sample taken during the course of the hydrolysis reaction was determined by HPLC fitted with a photodiode array detector. Five main components were detected. These compounds were identified as mphenylenediamine, m-aminophenol, resorcinol, 3,3’-aminodiphenylamine and 3- amino-3’-hydroxydiphenylamine by means of GC-MS. 3,3’-Diaminodiphenylamine is formed by self-condensation of MPDA and 3-amino-3’-hydroxydiphenylamine is formed by the reaction of MPDA with resorcinol. The degree of formation of these intermediates is substantially reduced when MPDA is added dose-wise to phosphoric acid at a reaction temperature of 220oC. The reaction mechanism of the hydrolysis reaction was investigated by isotopic lable incorporation, followed by analysis by NMR. This was done by hydrolysing MPDA using deuterated phosphoric acid (D3PO4). D3PO4 was generated by dissolving phosphorus pentoxide in deuterium oxide. The resorcinol product obtained from the hydrolysis using D3PO4 was found to be deuterated on the C-2, C-4 and C-6 positions. This suggests that the hydrolysis reaction involves protonation of MPDA on these positions, and this results in the formation of an iminium ion as one of the resonance forms. Hydrolysis then occurs on the positively charged carbon of this species. Fertiliser grade phosphoric acid can be used in the hydrolysis reaction, provided sulphates are removed before the acid is used in the hydrolysis reaction. The hydrolysis reaction using either ammonium sulphate or sulphuric acid produces resorcinol in yields lower than 60% if the hydrolysis is conducted in one pass. If these catalysts are used in the hydrolysis reaction, the reaction mixture needs to be re-heated after removal of resorcinol in order to increase the yield. Hydrolysis of MPDA using zirconium phosphate as catalyst gave resorcinol yields in excess of 90% over 24 hours. These reactions were carried out at very low concentrations of MPDA (0.3%). The mode of catalysis in these reactions is unclear. There is a possibility that the reaction is catalysed by phosphoric acid that leaches out of zirconium phosphate at high temperatures. The reaction might therefore not differ mechanistically from the phosphoric acid catalysed reaction. Further studies are required to clarify this point.
  • Full Text:
  • Date Issued: 2002

The legal effect of a coup d'etat on traditional constitutional concepts

  • Authors: Mkwentla, Nelson Koala
  • Date: 2002
  • Subjects: Coups d'état , Constitutional law
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: vital:3684 , http://hdl.handle.net/10962/d1003199 , Coups d'état , Constitutional law
  • Description: This thesis deals with constitutional law and other legal subjects such as Jurisprudence and Judicial Review. One constitution is distinguishable from another by its own provisions. These provisions are usually referred to as either the basic characteristics or features of the particular constitution and these are invariably derived from the basic political philosophy and constitutional arrangements of the particular country. A coup affects these characteristics in different ways. Some automatically disappear as being incompatible with the revolution; some are modified, others are strengthened. The usurpers may choose to set aside the constitution completely and replace it with another, or amend it to suit the new situation, or rule without any constitution. This often happens amidst the rattle of weapons and the whirr of military engines in and around the capital of a given country on that awesome occasion. This thesis sets out to examine the legal aspects of a coup d’ etat. The thesis is divided into six broad sections. Part one will deal with the theoretical background. I shall discuss an overview of Kelsen’s pure theory of law. The second part deals with the scope of its application in revolutionary situations and will also touch upon the reason behind the Kelsen’s theory as shown by decided cases from country to country. The third part deals with the essence as well as the significance of the doctrine of necessity to validate unconstitutional acts in the case of a coup d’ etat. This discussion is to pave the way for the fourth part which is to explore the position of judges who took oath of office under the old constitution. I am to explain their position after a coup d’ etat. The fifth part forms the gist of my research. I shall examine the effect of a coup d’ etat on traditional constitutional concepts such as fundamental rights, separation of powers, rule of law and judicial review in the military regime. The sixth part will deal with African experience. I shall include recommendations and conclusions drawn from the Lesotho and Uganda experiences.
  • Full Text:
  • Date Issued: 2002

The life history of selected coastal foredune species of South Africa

  • Authors: Knevel, Irma Cornelia
  • Date: 2002
  • Subjects: Sand dune plants -- South Africa Sand dune ecology -- South Africa
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:4207 , http://hdl.handle.net/10962/d1003776
  • Description: South African dune fields are severely threatened by human expansion and in the long run the stabilisation of many dunes will be necessary. The alien grass Ammophila arenaria is the most important drift sand stabiliser at present in South Africa. Although not invasive, the current impact of A. arenaria on the dune systems of South Africa is considerable, and thus the stabilising benefit of the grass seemed to may be outweighed by its negative consequences. It is therefore preferable to use indigenous sand stabilising species. In order to define guidelines for the application of indigenous plants for stabilisation, their autecology should be studied first to enhance the chance of successful stabilisation results. The main aim of the present thesis was to gather information on the life history processes of selected indigenous, sand stabilising foredune species. To investigate the growth of foredune pioneer species, the common pioneer Scaevola plumieri was followed over a three-year period to determine the growth season and leaf phenology. Soil-borne pathogens are known to influence the growth and vegetation dynamics of foredune species. To examine this effect on the South African foredunes the rhizosphere soil and the roots of several species were studied. To test the effect of the nematode fauna on succeeding plant species a transplantation experiment was carried out. The seed stage is the only life-cycle stage that can survive unfavourable conditions. Therefore, the seed ecology of several foredune species was studied extensively to determine the reproductive season, the seed production, the fate of seeds after shedding (germination, seawater dispersal), germination requirements and seed bank strategy. Seeds of the species Arctotheca populifolia, Ipomoea pes-caprae, Myrica cordifolia, and Scaevola plumieri were subjected to germination trials, field observations on seedling survival, and scarification and stratification experiments. This was done to obtain information about the germination requirements and to determine the reproductive season and growth season. The seed bank strategy of the foredune species, as well as the seed bank density, was determined by extensive sampling along the Cape coast. The species S. plumieri thrived under sand accretion situations, which makes it a good candidate for stabilisation purposes. The growth of S. plumieri was seasonal, with the highest leaf production during spring and summer. The stem position on the foredune had a strong effect on the overall performance of S. plumieri , with the stems situated on the landward face of the foredune showing higher leaf and seed production. Theiii nematode survey of soil and roots of several foredune species showed that all plant species featured a specific nematode fauna in the rhizosphere soil and the roots. The specific nematode fauna affected the growth of foreign plant species in the transplantation experiment, resulting in a lower root and/or shoot biomass production. Most of the foredune species produce seeds from spring to late summer. For S. plumieri the position of the stem on the dunes, as well as the predation of unripe seeds affected the number of seeds produced. The highest production was found for the landward faced stems. The S. plumieri seeds were able to float on seawater for at least three months without losing viability, as was observed for seeds of I. pes-caprae. The seeds of M. cordifolia, however, sank after a few days, but their viability was not affected. The rhizome fragments of A. arenaria and S. virginicus floated for 120 days, whereas the fragments of E. villosa sunk after one day. The viability of S. virginicus fragments was affected by the duration in seawater by an increase in sprouting time. The seeds of all species tested germinated readily under controlled conditions, except S. plumieri seeds which required a long lag-phase before germination. In the field the seeds of A. populifolia, I. pes-caprae and S. plumieri germinated, producing many seedlings. Only the seedlings of A. populifolia and S. plumieri survived. Of the species found in the foredunes 57% was represented in the soil seed bank. For most species, the seeds that were found in the seed bank showed viability of at least 40%. Many of the seeds found were older than one year, suggesting a short-term persistent seed bank. The present study is a start in filling the gap in information on dune pioneer and foredune species. The conclusion was that in general all species in the present study were easy to grow under controlled conditions, and thus could be used for stabilisation purposes. When the more rapidly growing pioneer species are planted in combination with succeeding foredune species, a functional and aesthetic ecosystem could be created.
  • Full Text:
  • Date Issued: 2002

The medicinal chemistry of the isomers of the cyclic dipeptide: cyclo(Trp-Pro)

  • Authors: Jamie, Hajierah
  • Date: 2002
  • Subjects: Pharmaceutical chemistry , Cyclic compounds
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:11023 , http://hdl.handle.net/10948/281 , Pharmaceutical chemistry , Cyclic compounds
  • Description: The isomers of cyclo(Trp-Pro) (cyclo(L-Trp-L-Pro), cyclo(L-Trp-D-Pro), cyclo(D-Trp-LPro) and cyclo(D-Trp-D-Pro)) have been successfully synthesized and screened for biological activity. High percentage yields were obtained by using the three phase synthesis system, which involves the synthesis of the intermediate protected linear dipeptides, followed by the removal of the protecting Boc groups. This step is followed by cyclization and crystallization of the isomers. The diketopiperazines rings of cyclo(L-Trp-L-Pro) and cyclo(D-Trp-D-Pro) contain cisamide bonds, while cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) contain trans-amide bonds. These bonds govern the conformation of the diketopiperazines ring. The isomers have shown different degrees of biological activity, possibly as a result of the orientation of the side chain of tryptophan and this difference in conformation, leading to varying interactions between isomer and a range of receptors. Under experimental conditions, 10-3 M cyclo(L-Trp-D-Pro) and cyclo(D-Trp-L-Pro) showed effective anticancer activity against the cervical cancer cell line, HeLa, resulting in a <50% reduction in cell viability. Cytotoxicity screening with cyclo(D-Trp-L-Pro) indicated that it was hepatocyte-specific in its toxicity, whilst the other isomers were cytotoxic against the other cell types tested. At 1mg/ml, cyclo(L-Trp-L-Pro) proved to be an effective antimicrobial agent against Gram positive bacteria, while cyclo(L-Trp-DPro) effectively inhibited the growth of the Gram negative bacteria, Esherichia coli. Cyclo(D-Trp-L-Pro) proved to be effective against Streptococcus, while cyclo(D-Trp-DPro) effectively reduced viability of the yeast, Candida albicans. Cyclo(D-Trp-L-Pro) was the only isomer to show Ca2+-channel antagonism, whilst the other isomers resulted in opening of the Ca2+-channel. No effects were observed on K+-channel activity for all the isomers tested. The isomers also proved to be valuable antiarrhythmic agents by effectively reducing the time spent in ventricular tachycardia and arrhythmia, as well as decreasing the time for the heart rate to return to a normal sinus rhythm. Furthermore, cyclo(L-Trp-D-Pro) showed positive chronotropic activity, while cyclo(D-Trp-L-Pro) ii showed negative chronotropic activity. In addition, cyclo(L-Trp-D-Pro) and cyclo(D-Trp- L-Pro) also increased the coronary flow rate. 0.125 –1 mM Cyclo(L-Trp-D-Pro) decreased aggregation in washed platelets induced by thrombin. All isomers increased adhesion to an artificial surface when the platelets were stimulated by ADP, yet caused reduced adhesion when the platelets were stimulated by thrombin. These results prove the potential of these compounds as novel agents in a range of biological fields, indicating that a combination of L- and D- amino acids may prove more effective than an agent consisting solely of L-amino acids.
  • Full Text:
  • Date Issued: 2002

The molecular microbial ecology of sulfate reduction in the Rhodes BioSURE process

  • Authors: Chauke, Chesa Gift
  • Date: 2002
  • Subjects: Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4082 , http://hdl.handle.net/10962/d1007475 , Water -- Purification -- Biological treatment , Acid mine drainage , Water -- Microbiology
  • Description: The research reported here investigated the use of a Baffle Reactor in order to study aspects of the biological sulfur cycle, where a floating sulfur biofilm formation occurs and where complex organic compounds provide electron donor sources. The development of a laboratory-scale Baffle Reactor model system satisfied the requirements for sulfate reducing bacterial biomass growth and sulfur biofilm formation. Since relatively little is known about the microbial ecology of floating sulfur biofilm systems, this study was undertaken to describe the sulfate reducing sludge population of the system together with its performance. A combination of culture- and molecular-based techniques were applied in this study in order to investigate the microbial ecology of the sulfate-reducing bacteria component of the system. These techniques enabled the identification and the analysis of the distribution of different sulfate reducing bacterial strains found within the sludge bioreactors. Strains isolated from the sludge were characterised based on culture appearance, gram staining and scanning electron microscopy morphology. Molecular methods based on the PCR-amplified 16S rRNA including denaturing gradient gel electrophoresis were employed in order to characterise sulfate-reducing bacteria within the reactors. Three novel Gram negative sulfate-reducing bacteria strains were isolated from the sludge population. Strains isolated were tentatively named Desulfomonas rhodensis, Desulfomonas makanaiensis, and Clostridium sulforhodensis. Results obtained from the Baffle Reactor showed that three dominant species were isolated from the DNA extracted from the whole bacterial population by peR. Three of these were similar to those mentioned above. The presence of these three novel unidentified species suggest that there are a range of other novel organisms involved in sulfate reduction processes.
  • Full Text:
  • Date Issued: 2002

The political ecology of wildlife conservation in Kenya, 1895-1975

  • Authors: Matheka, Reuben M
  • Date: 2002
  • Subjects: Wildlife conservation -- Kenya Environmental policy -- Kenya Wildlife conservation -- Political aspects -- Kenya
  • Language: English
  • Type: Thesis , Doctoral , PhD
  • Identifier: vital:2595 , http://hdl.handle.net/10962/d1007530
  • Description: The study examines the development of wildlife conservation policy and practice in Kenya from 1895 to 1975. Started by the colonial state as part of its resource control programme, wildlife conservation in Kenya gradually became an important aspect of the country's economy chiefly because of its significance as the basis of a vibrant tourist industry. The conservation programme was also important to conservationists who viewed Kenya's wildlife as a heritage to humanity. Similarly, local communities, which were affected in various ways by wildlife conservation policies, had their own perceptions of the programme. All this led to the proliferation of groups whose interests were potentially conflicting. Wildlife conservation in Kenya during the period under examination was thus characterised by various struggles between interest groups such as conservationists, the state, and local communities. The struggles centred around such issues as the costs and benefits of conservation and were manifested through anti-conservation activities like the poaching of wild animals by dissatisfied groups. These struggles changed over time in line with social, economic, political, and ecological developments. International events/processes (such as the two world wars, economic booms/depressions, and decolonisation) triggered local processes which influenced conservationism either positively or negatively. Wildlife conservation in Kenya during the period under study was dynamic. The thesis challenges the myth of a monolithic 'colonial' wildlife policy often implied in many studies on the subject. The thesis also lays emphasis on the ecological basis of wildlife conservation while recognising the impact of social, political, and economic developments on the evolution of wildlife conservation policy and practice in Kenya. The country's 'geography' not only provided the foundation for conservation but also influenced the programme over time. Droughts, floods, army worm infestations, and other 'natural' occurrences interacted with social and economic changes, such as population growth and the development of capitalism, to shape conservation policy. The conservation programme was thus influenced by a complex interaction of a variety of factors.
  • Full Text:
  • Date Issued: 2002

The pursuit of paternal custody

  • Authors: Pieterse, Johanna Tyziena
  • Date: 2002
  • Subjects: Custody of children -- South Africa , Paternal custody -- South Africa , Divorced fathers -- South Africa , Father and child -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:3398 , http://hdl.handle.net/10962/d1018266
  • Description: Issues concerning children may be the most intense and emotive areas of divorce and can lead to spectacular legal battles. Social work practice revealed that it is often the father who leaves the court, stripped of his fatherhood by a court order that only grants him limited access to his own children. Some divorced fathers disengage from their children's lives but there is documented evidence of South African fathers who desire continuity in their relationships with their children after divorce. An interest in these fathers prompted this study. Fathers who challenged maternal custody were selected since it was assumed that their lived experiences would include non-custodial as well as custodial fatherhood. The study was approached from a constructivist position and was further informed by a family systems theory. South African and international literature was perused followed by an exploratory study on the relatively uncharted terrain of paternal custody. A qualitative method was used and one unstructured interview with a schedule was conducted with each of the five respondents who were selected according to non-probability purposive sampling methods. Interviews were recorded and transcribed verbatim. Data was analysed cross-sectionally around certain themes and categories that were extracted from the data. The most significant findings of the study which appear to resemble some earlier national and international findings, are summarised as follows: Some fathers appear to have sound motives for pursuing custody of their children. These fathers, if afforded the opportunity, find fulfilment in parenting their children whom they perceive to be happy and prosperous in their care. There are fathers in whom divorce causes clear and profound signs of distress which appear to be related to the loss of the pre-divorce father I child relationship. The feeling of powerlessness to effect the well-being of their children as they see it was emphasised. Recommendations generated from these findings relate to the elimination of gender bias from custody decisions, including fathers in therapeutic interventions with divorced families and the provision of family courts and mediation services as suggested in the White Paper for Social Welfare. Recommendations for future research are also presented.
  • Full Text:
  • Date Issued: 2002

The relationship between the leadership, internal quality, and customer satisfaction levels of dealerships in a South African motor vehicle organisation

  • Authors: Botha, Jennifer
  • Date: 2002
  • Subjects: Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
  • Language: English
  • Type: Thesis , Masters , MCom
  • Identifier: vital:1185 , http://hdl.handle.net/10962/d1002802 , Consumer satisfaction , Automobile dealers -- South Africa , Industrial productivity , Customer services
  • Description: This research investigates the relationship between the leadership, internal quality, and customer satisfaction levels in the dealerships of a South African motor vehicle organisation. The Service Profit Chain provides the background theory to this relationship, by suggesting that various factors within the service delivery system of an organisation affect the level of customer satisfaction. From the Service Profit Chain, it is established that two of the prevalent factors affecting customer satisfaction, are leadership and internal quality. The Full Range Leadership Development Theory provides the backdrop for analysing the leadership style of each dealership by using the Multifactor Leadership Questionnaire. The Competence Process forms the theoretical construct against which the internal quality of these dealerships is assessed using the Organisation Competence Analysis Questionnaire. Information was gathered, using these two instruments, from a sample of 85 motor vehicle dealerships within South Africa. The customer satisfaction levels at each of these dealerships, is measured by the motor vehicle organisation’s own instrument, known as the Customer Satisfaction Index. Data obtained from each instrument, for the respective dealerships, was then statistically analysed. However, due to the low reliability of the instruments used in this research, the results of this study indicate that there is no relationship between the leadership, internal quality, and customer satisfaction levels within a South African motor vehicle organisation. Therefore we can conclude that the null hypotheses can not be rejected.
  • Full Text:
  • Date Issued: 2002

The relationship between three anxiety related clusters in projective drawings and anxiety and ego-strength scales of the Minnesota multiphasic personality inventory-2

  • Authors: Brink, André
  • Date: 2002
  • Subjects: Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2942 , http://hdl.handle.net/10962/d1002451 , Projective techniques , Personality assessment , Personality tests , Anxiety , Minnesota Multiphasic Personality Inventory
  • Description: Based on the shortcomings of past research, the need for understanding and investigation of the general relationship between self-report measures and human figure drawings required understanding and investigation (Riethmiller & Handler, 1997b; Waehler, 1997) while utilising a quantitative, configural scoring approach. Riethmiller and Handler (1997a; 1997b) hypothesised that subjects have one of two typical approach styles to anxiety/stress that influences their execution of the Human Figure Drawing (HFD) Test: “Avoidance” or “Coping” as measured by composite scoring index clusters. They argue that these two approach styles had to be taken into account when investigating anxiety on the HFD Test. According to Handler and Reyher (1965) those who experience more intense anxiety typically rely on an “Avoidant” approach, while those with lower anxiety typically rely on a “Coping” approach. The “Coping” response is hypothesised to suggest good ego-strength, and the “Avoidant” response poor ego-strength. Handler and Reyher (1964; 1965; 1966) also argued that there are two sources of anxiety on projective drawings: internal and external sources of anxiety. They hypothesised that the “External” anxiety cluster (measured by utilising the car drawing) and self-report measures both assess ‘external’ anxiety. Using Handler’s (1967) HFD index scoring manual, this research therefore inve stigated the level of correlation of the two MMPI-2 anxiety scale scores with (a) the hypothesised Stress Approach HFD cluster scores, as well as with (b) the “External” anxiety cluster score, while the hypothesised Stress Approach HFD cluster scores were compared with the (c) MMPI-2 ego strength scale score. The results of the investigated relationships yielded non-significant correlations overall. The differences in nature of the two measurement instruments, and the potential weaknesses of this study, as two likely explanations for these correlations, are discussed. In the consideration of the differences of the two measurement instruments, the weaknesses of SR measures and criterion-related validity are discussed while self- attributed and implicit motives are contrasted with each other. Potential extraneous variables and possible truncated range are discussed as potential weaknesses of this study.
  • Full Text:
  • Date Issued: 2002

The remote configuration of devices within home entertainment networks

  • Authors: Dembovsky, Colin
  • Date: 2002
  • Subjects: Home entertainment systems , Home video systems
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4685 , http://hdl.handle.net/10962/d1007795 , Home entertainment systems , Home video systems
  • Description: This thesis examines home entertainment network remote configuration solutions. It does so by inspecting four home entertainment networking solution specifications - HAVi, Jini, AV/C and UPnP. Two of these (AV/C and UPnP) are implemented partially for a system allowing a TV to configure an AudioNideo Receiver (AV/R) remotely on the network (a process known as remote configuration). The two implementations are then more closely investigated and several implementation differences in the approach between the remote configuration method of device configuration and other methods of device configuration are discerned. These different approaches are then categorised into one of two theoretical models of communication for configuring devices on home entertainment networks - the Rendering model and the Programmed model. By classifying a particular method of device configuration into one of the two models, manufacturers can quickly determine the inherent strengths and weaknesses of that method , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
  • Full Text:

The role of cellulases and glucohydrolases in the solubilisation of primary sewage sludge

  • Authors: Ngesi, Nosisa
  • Date: 2002 , 2013-05-09
  • Subjects: Sewage sludge , Sewage sludge digestion , Cellulase , Glucosidase inhibitors , Hydrolases , Sulfates
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4080 , http://hdl.handle.net/10962/d1007454 , Sewage sludge , Sewage sludge digestion , Cellulase , Glucosidase inhibitors , Hydrolases , Sulfates
  • Description: Biological sulph ate reduction has been identi fied as a potentially valuable process for removing sulphate and heavy metals from indllstrial effluents. The role of sulphate reducing bacteria (SRB) in this process has attracted the attention of biotechnologists and recently of enzymologists due to its fundamental properties and possible role in AMD bioremediation. These obligatory anaerobic sulphate-reducing bacteria are commonly known to dissimilate sulphate for energy. Under anaerobic conditions SRB oxidize simple organic compounds such as lactic acid with the sulphate and thereby generate hydrogen sulphide (a stTong reducing agent) and bicarbonate ions. The hydrogen sulphide in turn reacts with contaminant metals contained in AMD and precipitates them out of solution as metal sulphides. Bicarbonate ions neutralize AMD by reaction with protons to form carbon dioxide and water. Organic matter in the municipal sewage sludge has been identified as a potential source of electron donors for su lphate reduction. However, this organic matter is in the polymeric form that cannot be util ised by SRB. The latter depend on the activities of other hydrolytic bacteria for the degradation of complex polymers. Hence the availability of these monomeric substrates is a major factor, which may constrain further process development and is considered a rate-limiting step. Thi s study is therefore undertaken to investigate the bacterial glucohydrolase enzymes involved in the digestion of the polysaccharides present in the sewage sludge with specific interest in cellulases and/or p-glucosidase enzymes. The goals of the research are to: isolate, identify, purify and quantify these enzymes; study their distribution with respect to time, pH, and temperature; maximize and quantify the hydrol ys is products; study whether sulphide and sulphate have an enhancing or an inhibitory effect on the activity of enzymes; optimize the enzyme activity against substrate and/or product inhibition and soluble heavy metal salts. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
  • Full Text:
  • Date Issued: 2002

The selection paradox: selecting and evaluating trainee psychologists in the context of narrative theory

  • Authors: Kaschula, Joanne
  • Date: 2002
  • Subjects: Psychologists -- Training of -- South Africa , Psychology -- Study and teaching -- South Africa , Psychologists -- Selection and appointment -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSocSc
  • Identifier: vital:3001 , http://hdl.handle.net/10962/d1002510 , Psychologists -- Training of -- South Africa , Psychology -- Study and teaching -- South Africa , Psychologists -- Selection and appointment -- South Africa
  • Description: Psychology has become an increasingly popular discipline for study in the South African context, with the number of students enrolling for courses increasing rapidly. The selection and evaluation of trainee psychologists is a complex and contested issue. With so few students reaching Masters level and the changing needs of the South African context, it becomes imperative that only the most suitable candidates are selected for entry into the field of professional psychology. This study focuses on the selection process of trainee psychologists at an institution that incorporates the narrative philosophy in both the selection and training of candidates. The question is raised, whether it is possible to utilize narrative principles in a process that is intended to judge and evaluate candidates? This presents a paradox. The paradox is illuminated in both the intentions behind the narrative questions in the application form and in the candidates' experiences of responding to these. The conclusion reached is that the narrative philosophy makes for an enriching and creative experience of the selection process for candidates but this however, does not ameliorate the negative effects of evaluation and the 'gaze'.
  • Full Text:
  • Date Issued: 2002

The teaching of ecology in schools: a literature review

  • Authors: Wiredu, Christopher Agyei
  • Date: 2002
  • Subjects: Environmental education Teachers -- In-service training -- South Africa Science -- Study and teaching -- South Africa Ecology -- Study and teaching
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:1413 , http://hdl.handle.net/10962/d1003134
  • Description: Project 1: This is a literature review on the teaching of ecology in South African schools. The importance of ecology education in the school curriculum is well reported. It is also reported that in spite of the apparent importance of the subject, not much ecology is taught or learned in schools. This report examines what ecology is supposed to be about and the challenges that confront its teaching. The approaches to teaching the subject are also discussed. It would seem that if teachers focus on teaching ecological concepts using constructivist teaching/learning strategies, students might be helped to learn ecology meaningfully. Project 2: 'Constructing eco-concepts' is a case study that reports the effects of a module whose design was informed by social constructivist ideas on the understanding of selected ecological concepts by college students. Social constructivism as a philosophy of learning has gained increasing attention in science education in recent times and yet the approach is so alien to so many. Many teachers still teach by the traditional teacher-centred approaches. This research project reports the conceptual change of students after undertaking the module. It also reports the students' perceptions about the teaching/learning strategies employed in the module. It would seem that the social constructivist strategies used in the module assisted the students to improve their frameworks of ecological concepts. Data also tend to reveal that the students enjoyed the approach to learning and had positive views about the social constructivist teaching/learning approach. Project 3: With the advent of the new curriculum framework for South Africa, the outcomes based curriculum, it would seem that teachers could no longer approach teaching by the traditional transmission methods. Colleges of education have been criticised for producing teachers who do not seem to be adequately prepared for their job. Presently, the argument seems to be that teachers would need in-service education on a wide scale and the colleges of education would seem to be important in-service teacher education centres. This research, using case study methodology, investigated the potential of one of the colleges of education to become an in-service teacher education institution based on its physical and human resources.
  • Full Text:
  • Date Issued: 2002

The variation of conditions of employment

  • Authors: Horo, Lindile
  • Date: 2002
  • Subjects: Labor laws and legislation -- South Africa , Labor disputes -- South Africa , Collective bargaining -- South Africa
  • Language: English
  • Type: Thesis , Masters , LLM
  • Identifier: vital:11043 , http://hdl.handle.net/10948/282 , Labor laws and legislation -- South Africa , Labor disputes -- South Africa , Collective bargaining -- South Africa
  • Description: This paper seeks to bring clarity to a number of issues that arise from a process resulting from the unilateral variation of terms and conditions of employment and the conflict management and dispute resolution processes. The variation of employment terms particularly when it is driven by one party to the employment relationship can cause instability, insecurity, confusion and uncertainty to the parties involved. The nature of work is not constant and therefore changes are inevitable. This then has an effect of bringing disorder not only to the employer-employee relationship but also to the labour relations balance. In many instances and depending on whether it is the employer or employee who propagates the changes, the reasons to alter the conditions are different. Employers usually cite operational or economic reasons that are meant for the survival of the business as the need to make the changes. From the employees’ side the changes are necessitated by reasons aimed at a move from protecting the favourable employment conditions already acquired to improving them or attaining more. In the event that the parties to the employment relationship do not agree to the changes proposed and implemented, a dispute usually arises. This results from the failure of a consultation process, negotiations, persuasion or collective bargaining in general. In essence such a dispute arises from absence of consent to the changes. The failure of a bargaining system requires the process to assume a new nature. The dispute resolution systems and the conflict management systems follow as both the appropriate and necessary steps. The bargaining power together with the intervention of the third party is at the centre of this phase. The parties, depending on the nature of the dispute, the conditions that iv are changed and who are affected by the changes, have choices on what dispute resolution mechanisms to employ. The choice made has a huge impact on both the outcome required in the form of recourse, how the dispute will be resolved or how the conflict will be managed. There is legislative intervention with regards to the resolution of the conflictual scenarios that arise from disputes on unilateral variation of terms and conditions of employment. There are also non-statutory measures available to the parties. The choices are vast as to when can the variation take place, the reasons for the changes, the parties involved, the possible dispute resolution mechanisms, what can be varied and whether the unilateral implementation can be viewed as fair.
  • Full Text:
  • Date Issued: 2002

Theatre and science, with specific reference to Shelagh Stephenson's An experiment with an air pump (1999)

  • Authors: Van Niekerk, Dion
  • Date: 2002
  • Subjects: Science in literature , Stephenson, Shelagh -- Experiment with an air pump
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2152 , http://hdl.handle.net/10962/d1004270
  • Description: Science has featured intermittently as the subject of theatrical texts since Thomas Shadwell first represented the Renaissance scientist in The Virtuoso (1676). The late twentieth century, however, saw an incremental growth in theatre's interest in scientific exploration, a growth concommitant with the vast impact that science has had on technology, warfare and the machinations of political power. The tensions generated by the disjuncture between the rationality of science and the unpredictability of human society have provided a rich source of material for theatrical investigation into the human experience. The purpose of this thesis is twofold: to reveal some of the thematic concerns that emerge in this genre, and to examine the interplay between theatre and science. Shelagh Stephenson's An Experiment with an Air Pump (1999) provides a useful point of focus for this inquiry. By parallelling two time periods, exposing the scientific objectification of women and, in addition, opening up contemporary ethics for negotiation with the audience, Stephenson calls into question the objectivity and certainty of history, gender and ethical conduct. These she presents as dynamic and evolving fields of discourse that contribute to, but do not solely constitute, knowledge and understanding of the world. An Experiment with an Air Pump also displays an awareness, through its metatheatricality, of theatre itself as an imaginative, subjective discourse which parallels the more intuitive and personal aspects of scientific exploration. The play functions as a microscope, bringing into focus a contemporary world in which traditional systems of understanding and knowledge need to be reassessed and reinvented.
  • Full Text:
  • Date Issued: 2002

Thermal and photostability studies of furosemide and its cyclodextrin mixtures

  • Authors: Melane, Babalwa Blossom
  • Date: 2002 , 2013-05-16
  • Subjects: Furosemide , Furosemide -- Stability
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4440 , http://hdl.handle.net/10962/d1007625 , Furosemide , Furosemide -- Stability
  • Description: Furosemide (Lasix®), abbreviated as FR and also known as frusemide, is a drug used for renal problems and treatment of cardiac edema. Various polymorphic forms of furosemide, dependent upon the method of preparation and thermal treatment, have been reported. The main thermal decomposition product of furosemide has been identified as saluamine. The dissolution properties of furosemide have also been reported to be improved by complexation with beta-cyclodextrin. Photostabilities of the different crystal forms have been studied. Differential scanning calorimetry (DSC) and thermogravimetry (TG) have been used to examine the thermal behaviour of furosemide itself and of its physical and kneaded mixtures with betacyclodextrin (BCD) and gamma-cyclodextrin (GCD). There is strong evidence from DSC that complex formation between FR and GCD occurs. This is supported by IR and XRD data. Decreases in the intensity and broadening of the characteristic carbonyl (1660 cm'l) and amine (1588 cm⁻¹) bands in the kneaded mixture, compared to the physical mixture, were observed with IR. X-ray diffraction results for the 1:3 molar ratio FR/GCD kneaded mixture showed a halo diffraction pattern characteristic. of an amorphous solid and did not resemble patterns from the drug, or the gamma, cyclodextrin, or the physical mixture. Photostability studies have been conducted on solid furosemide and its mixtures with GCD or BCD. An HPLC method was developed to determine the amount of drug remaining after exposure and the presence of any degradants. Results indicated that about 10% degradation of the drug occurred during exposure for 16 hours at 550 W/m², with the appearance of polar degradants. Although IR and DSC results for the 1:3 molar ratio FR/GCD kneaded mixture showed a probable strong interaction between FR and GCD, the photostability of FR was decreased. The 1 :3 molar ratio FR/BCD kneaded mixture showed less photo-degradation than the 1:3 molar ratio FR/GCD mixture under similar conditions, suggesting that inclusion of the drug molecule (FR) is different in the two cyclodextrins.
  • Full Text:
  • Date Issued: 2002

Thermophilic lignin degrading enzymes from actinomycetes for biotechnological applications

  • Authors: Mhlanga, Chido Yvonne Lois
  • Date: 2002 , 2013-05-16
  • Subjects: Actinomycetales -- Biotechnology , Lignin
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4085 , http://hdl.handle.net/10962/d1007628 , Actinomycetales -- Biotechnology , Lignin
  • Description: Phenolic residues which accumulate in the environment as a result of agro-industrial practices has resulted in the need to find and use Eco-Friendly techniques, rather than the traditional methods of burning or burying this kind of waste. Bioremediation and bioconversion are attractive alternatives using whole cell or enzyme-based systems. The aims of this project were to isolate and uses thermophilic Actinomycetes, which produce thermo-tolerant oxidoreductase enzymes, which can be used to bioconvert a model industrial phenolic waste commonly genersated in the wine-making industry of South Africa. Current research in bioconversion and bioremediation focuses on mesophilic microbes in that their enzymes can catalyse reactions at higher temperatures without affecting its activity and lower contamination levels. Three novel Actinomycete isolates were isolated (RU-A0l , RU-A03 and RU-A06) from a compost site and characterized using a combination of conventional identification techniques and 16S rDNA methodology to identity the three isolates. All three isolates belong to the Streptomyces clade. In addition, five known Actinomycetes were selected from an internation culture collection and also screened for oxidoreductase activity in comparision to the three novel isolates. Although the five isolates were selected based on their ability to produce oxidoreductase enzymes, unexpectedly, no activity was detected. Screening assays for peroxidase, polyphenol oxidase and laccase on RU-AO 1, RU-A03 and RU-A06, showed that all three isolated produced peroxidases and peroxidases but no laccase. Substrate specificity studies revealed that the most suitable substrates to determine peroxidase and polyphenol oxidase activity on these isolates were catechol for polyphenol oxidase, 2,4-dichlorophenol for peroxidases and veratryl alcohol for lignin peroxidases. Previous studies have indicated that peroxidases and polyphenol oxidases are produced in Actinomycetes during the primary stage of growth. This was the case with RU-AOI , RU-A03 and RU-A06. Growth rates were higher that other Actinomycetes, with maxImum biomass being reached at 36 hours for the isolates RU-AOI and RU-A06 and 48 hours for isolate RUA03. pH studies showed that the three isolates were adaptable and could grow over a broad pH range. Catabolism studies of phenolic model compounds showed that the three isolates were capable of catabolizing the model phenolic compounds within a period of 24 hours. Further studies were carried out to determine the effect of these microbes and their enzymes in whole cell and enzyme-based systems on a model phenolic waste, graoe waste consisting of compressed grape skins, pips and stalks. Whole cell studies showed that the isolates were capable of bioconverting the waste at a maximum concentration of 30% grape waste (vol:vol). Peroxidase and polyphenol oxidase activity increased indicating induction of these enzymes in the presence of phenolic compounds, with a maximum increase of up to 15.9 fold increase in extracellular lignin peroxidase activity in RU-AO1. HPLC and phenolic determination assays indicated that bioconversion of the phenolic grape waste had occurred in the presence of the three isolates. Attempts were made to isolate and identify a peroxidase or phenol oxidase gene from one the isolates. As bacteria, Actinomycetes are amendable to gene manipulation making them suitable candidates for methods such as site directed evolution in comparison to fungi. Two clones were selected for sequencing based on positive activity results when assayed for peroxidase activity. However the resultant sequences did not identify a functional gene sequence. Southern Blotting was then carried out to determine the nature of the peroxidase gene. Previous studies have been focused on the catalase-peroxidase gene (CalC gene) found Actinomycetes and other bacteria. A probe was developed from the CalC gene. No hybridization occurred with any of the enzyme restricted DNA from the three isolates. The implications of these results are that the peroxidase genets in the three isolates are in fact lignin peroxidase in nature. This project has the potential in the bioconversion of phenolic wastes and is the first description of the use of thermophilic Actinomycetes in the bioconversion of an industrial phenolic waste.
  • Full Text:
  • Date Issued: 2002

Towards a broader socio-ecological education : a case study of school based curricular reform

  • Authors: Cimma, Gary Martin
  • Date: 2002
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: vital:20973 , http://hdl.handle.net/10962/5763
  • Description: This work documents and analyses an action research project that the researcher undertook in conjunction with colleagues at an independent Catholic high school in Johannesburg. The main objective was to try to expand the existing curriculum in operation at the time of starting the research to one, which was more socio-ecologically sensitive. One of the key references during the action research was the recently drafted ‘Vision Statement’ document, which detailed the educational ideals of the school. Some of the key findings that emerged as the research proceeded, were that the levels of socio-ecological sensitivity displayed by the learners were influenced by the backgrounds from which they came, and that these background environments were often not comfortable with the changes taking place in the educational and greater South African environments. The Participatory Action Research mode of research which was used proved to be problematic in that only a handful of the educators actually got involved in participating in the project. The failure of many of educators to get involved was, in the opinion of the researcher, due to their lack of understanding how important the development of social and ecological sensitivity are to the necessary change capacity required in present day South African society. The need to be involved in the ongoing development of curriculum as required by Curriculum 2005 as a form of Outcomes Based Education was also problematic as some educators were not familiar with their role in this regard. The limited time-span of the research was also a limiting factor as the development of a socio-ecologically sensitive curriculum required changes in some fundamental attitudes and approaches to education and the environment.
  • Full Text:
  • Date Issued: 2002

Towards the performer-creator in contemporary mime, with specific reference to the physical theatre of Andrew Buckland, 1988-2000

  • Authors: Murray, Robert Ian
  • Date: 2002
  • Subjects: Buckland, Andrew , Mime , Mimes -- South Africa
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2158 , http://hdl.handle.net/10962/d1007720
  • Description: Part one of this thesis investigates the conceptualisation of the performer-creator and its relevance in late twentieth century physical performance by examining some of the theoretical, but mainly artistic, traditions that suggest a movement towards this. Chapter one tackles the question of definition, linking mime within a wider physical theatre phenomenon. Chapter two looks at the importance of mime training for contemporary performance. This requires a focus on selected theatre practitioners who have significantly advanced the development of mime training and performance during the twentieth century. Chapter three examines the issue of silence in mime and questions a potential liberation of the word and language in contemporary performance and consequently how this affects the role of the performer, particularly in South Africa. Chapter four investigates the figure of the theatrical clown and how this late twentieth century development is playing an increasingly important role in contemporary performance. Chapter five then wraps up part one by pulling the preceding chapters together and thereby providing a working conceptualisation of the performer-creator, locating it within an overall appreciation of contemporary mime. Part two then tests the notion of the performer-creator by focussing on a case study through the investigation of Andrew Buckland to develop this idea. Andrew Buckland, and his work under the ethos of Mouthpeace from 1988-2000, provides a clear and unique example of this movement in contemporary South African performance. Trained as an actor and in classical illusion-based mime technique, as well as many dance forms such as ballet, contemporary and jazz, he has virtually single-handedly created and shaped a particular performance trend that is in line with contemporary international trends but retains a distinctive South African flavour. There is no space to attempt a definitive or exhaustive examination of his works, and nor is the intent to do so; rather, the aim is to draw from his work their essences that reveal his development as an artist: as both a creator and a performer.
  • Full Text:
  • Date Issued: 2002

Traditional leaders in post-1996 South Africa, with particular reference to the Eastern Cape

  • Authors: De Sas Kropiwnicki, Zosa Olenka
  • Date: 2002
  • Subjects: Tribal government -- South Africa -- Eastern Cape , Political leadership -- South Africa -- Eastern Cape , South Africa -- Politics and government
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2857 , http://hdl.handle.net/10962/d1007479 , Tribal government -- South Africa -- Eastern Cape , Political leadership -- South Africa -- Eastern Cape , South Africa -- Politics and government
  • Description: The failure of democracy in Africa can be partially attributed to the Eurocentric assumptions that belie Western recommendations for Africa. This thesis focuses on the failure of the modernisation school to account for the resiliency of tradition in the modern African state, which is described by Sklar (1991) as amounting to a form of 'mixed government', combining the traditional with the modern to create a uniquely African form of governance. This notion of a 'mixed government' is addressed from the vantage point of traditional leaders in the Eastern Cape. It maps the vacillating relationship between the chiefs, the people and the government through colonialism, Apartheid and democratisation. It concludes that although the Eastern Cape provincial government has subordinated the chiefs, this does not signify a victory for modernity over tradition because the chiefs are not a spent force. History has shown that when the government fails to act in the interests of the people, they seek an alternative authority namely, the chiefs. The ANC government's centralising tendencies have negative implications for democracy and consequently for the people. This opens up space for the chiefs to assert themselves provided they play an active role in furthering democracy, development and modernisation in the interests of the people. Hence, although ' mixed' government in the post-1996 South Africa is currently on the ANC's terms, traditional leaders may someday play a vital role in the modern democratic state.
  • Full Text:
  • Date Issued: 2002
  • Disclaimer
  • Privacy
  • Copyright
  • Contact