Title not specified
- Authors: Venda men and boys , Tracey, Andrew T N
- Date: 2002
- Subjects: Venda --(African people) , Folk Music , Mbira , Sub-Saharan African music , Africa South Africa Venda f-sa
- Language: Venda
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/112161 , vital:33554 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC126b-01
- Description: Venda traditional music with Mbila Mutondo accompaniment
- Full Text: false
- Date Issued: 2002
Genetic characterization of conspecific populations of Tilapia Sparrmanii (A.Smith 1840) in the dolomitic sinkholes and springs of the North-West Province (South Africa), and their comparison to Tilapia Guinasana (Trewavas 1936)
- Authors: Nxomani, Clifford David
- Date: 2002
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4079 , http://hdl.handle.net/10962/d1007452
- Description: This study was undertaken to investigate the genetic relationships of allopatric populations of the cichlid fish, Tilapia sparrmanii (A. Smith 1840) inhabiting the sinkholes and springs of the North West Province, South Africa. It also examined the genetic relationships of T sparrmanii to its polychromatic sister species, Tilapia guinasana (Trewavas 1936) which is endemic to the Guinas sinkhole in Namibia. Finally, the study investigated whether there is a genetic basis for T guinasana's colour polymorphism. The research was prompted by the concern of conservation authorities about the possible loss of unique fauna given the high demand for use of the subterranean waters for agricultural, domestic and industrial purposes. Such demands have the potential to drain these habitats. Further concerns related to habitat destruction and the introduction of alien species in the ecosystems inhabited by both fish species. Three approaches were adopted in attempting to answer the above questions. First was the investigation of Sodium dodecylsulphate (SDS)-Polyacrylamide Gel Electrophoresis (PAGE) of total cellular proteins as a fast and relatively inexpensive indicator of genetic relatedness between the fish populations. Secondly, genetic differentiation between the T sparrmanii populations and its relationship to T guinasana were assayed using restriction endonuclease analysis of Polymerase Chain Reaction (PCR)-amplified regions of the cytochrome b gene and the d-Ioop of mitochondrial DNA, coupled with Temperature Gradient Gel Electrophoresis (TGGE) analysis of the same regions. The third approach involved the use of Random Amplified Polymorphic DNA (RAPD) fingerprinting of the populations ofT sparrmanii as an indicator of genetic differentiation between them. RAPD fingerprinting was further used to investigate the genetic relationships between T sparrmanii and T guinasana and to probe the genetic basis of the polychromatism of the latter. SDS-PAGE did not reveal any genetic differentiation between the T sparrmanii populations, nor could the analysis detect variation within them. It however clearly distinguished at a species level between T sparrmanii and T guinasana as well as between these and other fish species, thus indicating its possible utility as an indicator of genetic relatedness at a species level. Mitochondrial studies employing the Restriction Fragment Length Polymorphism (RFLP) of Polymerase Chain Reaction (PCR)-amplified cytochrome b (1.1 kb) and d-Ioop regions (0.9 kb) with six and five restriction enzymes respectively, failed to reveal genetic differences within and between the allopatric populations. TGGE of500 bp of the d-Ioop and 400 bp of the 12sRNA PCR-amplified fragments did not reveal any differences between the populations of T. sparrmanii, nor did the analysis reveal any differences between T. sparrmanii and T. guinasana. The lack of differentiation between the T. sparrmanii populations by these mitochondrial Dna analysis techniques, despite habitat fragmentation, indicated a recent origin of the populations from a common ancestral population. Failure to distinguish between T. sparrmanii and T. guinasana may be related to the sensitivity of the techniques utilized. RAPD fingerprinting analysis indicated that the populations are genetically differentiated from each other. Using a measure of coefficient of variation, the population with the highest variation was the Wondergat population (13.99%), followed by the Klerkskraal popUlation (8.29%), the Malmani and Marico Oog populations (each with 5.88%) and the least variation (4.95 and 4.83%) was with the Amalinda and Molopo Oog populations respectively. This high degree of intra population similarity points to the fact that this differentiation is still confined within the limits of con specificity. The genetic distances between all of the T. sparrmanii populations across all primers ranged from 0.09 to 0.234 and averaged 0.146, a value that falls in the upper end of conspecific population differentiation. Such results indicate populational sub-division below the species level. RAPD fingerprinting therefore proved more sensitive than protein or mitochondrial studies. The differentiation it detected between the populations is a reflection of their adaptation to local conditions of the unique ecosystems they inhabit. A comparison with a subset of primers between T. guinasana and T. sparrmanii confirmed the separate species status of the former from the latter. The mean genetic distance between the T. sparrmanii populations was 0.136, compared to that between T. sparrmanii and T. guinasana which was found to be 0.374. Statistical analysis of the difference between the mean genetic distances indicated significance with 95% confidence. The polychromatism of T guinasana was investigated to determine whether there were significant differences between its five colour morphs. RAPD fingerprinting indicated with 95% confidence that there were significant differences between the colour forms based on the genetic distances computed between them. These genetic differences appeared to correlate with the observed assortative mating between the colour forms of the species. The manifestation of the polychromatism at sexual maturity in T guinasana probably indicates that colouration plays an important role in the breeding process. The genetic uniqueness shown here between the populations of T sparrmanii and the colour forms of T guinasana indicate for protective measures to be put in place if the genetic resources of the isolated fish populations are to be preserved. These must be coupled with a thorough assessment of the temporal and spatial distribution of genetic variability of the populations as a guide to a long-term management strategy for the fish populations and the ecosystems they inhabit. This study therefore has shown that the allopatric populations of T sparrmanii in the sinkholes and springs of the North-West Province are genetically unique, as well as show that the colour forms of T guinasana are genetically distinct.
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- Date Issued: 2002
Effects of substituents on the photosensitizing and electrocatalytic properties of phthalocyanines
- Authors: Maree, Suzanne Elizabeth
- Date: 2002
- Subjects: Phthalocyanines
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4554 , http://hdl.handle.net/10962/d1018247
- Description: In this work a selection of octasubstituted phthalocyaninato Zinc, Ge(IV) and Sn(IV) complexes were synthesized for possible use in photodynamic therapy and their photochemistry, photophysics and electrochemistry studied. Third-generation complexes containing steroids, e.g. cholesterol and estrone, were synthesized to improve tumour selectivity. The zinc phthalocyanine complexes (ZnPc) showed that complexes containing electron-donating groups have higher photostability. Germanium phthalocyanine complexes (GePc) undergo phototransformation rather than direct photobleaching and the tin phthalocyanine complexes (SnPc) undergo photobleaching mediated by photoreduction of the phthalocyanine ring. Singlet oxygen production showed increased in the following order: GePc>SnPc>ZnPc. Triplet lifetimes of the GePc (168-340μs) are very similar to that of the ZnPc (197 - 366μs), but the triplet lifetimes of the SnPc are ten fold shorter (10 - 32μs ). Triplet quantum yields are higher for the GePc (0.20 - 0.50) and SnPc (0.08 - 0.45) than for the ZnPc (0.02 - 0.25). Fluorescence lifetimes of GePc ( 4.0 - 5.1 ns) are significantly longer than that of ZnPc (1.9 - 3.0 ns) and SnPc (0.2 - 0.4 ns). Fluorescence quantum yields decrease in the following order: GePc(0.21-0.31)>ZnPc(0.02-0.21)>SnPc(0.02- 0.06). Ring-substituted cobalt phthalocyanine complexes of the form CoPc(R)4 (R= NH2, N02, C(CH3)3, S03H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the Com/Co11 couple of the CoPc(R)4 complexes in acidic media and to the Con/Co1 couple in basic media. The catalytic current and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive and the currents increasing with increase in pH.
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- Date Issued: 2002
Naming students problems: an analysis of language-related discourses at a South African university
- Authors: Boughey, Chrissie
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6086 , http://hdl.handle.net/10962/d1008484 , http://www.tandfonline.com/doi/pdf/10.1080/13562510220144798
- Description: This article examines a number of discourses that construct students 'problems' as they engage with tertiary study at a historically black South African university. These dominant discourses are then linked to Street's 'autonomous' model of literacy and Rampton's 'autonomous' model of applied linguistics in order to interrogate their ideological biases. Implications of the discourses for the provision of epistemological access to tertiary study are then explored. The article ends by indicating how a 'literacy across the curriculum' approach to working with students' difficulties could provide an alternative to current 'remedial' programmes.
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- 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.
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- Date Issued: 2002
Bad faith: the psychological life of a satanist who committed murder
- Authors: Du Toit, Jacobus Petrus
- Date: 2002
- Subjects: Murderers -- Psychology , Criminal psychology , Satanism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3152 , http://hdl.handle.net/10962/d1007483 , Murderers -- Psychology , Criminal psychology , Satanism
- Description: Traditional methods of psychological and forensic research fail to adequately provide an account of the psychological meaning that perpetrators of crime derive when appropriating their actions to Satanic involvement. In February 2001, a young man appeared in a South African High Court and testified that he had committed murder as a result of his involvement in Satanism. The aim of this study is to gain a phenomenological understanding of how this man appropriates the act of murder to involvement in Satanism. A review of literature elucidates Satanism as a context for meaning, provide a framework for defining murder as a criminal act, and situate this study in the broader field of phenomenological-existential, psychological research. An emergent design case-study approach was applied to data gathered from a single subject, by means of a three-interview series. An empirical phenomenological methodology was used during the interpretive phase to arrive at both a descriptive account of the subject's phenomenological experience and how the eidetic structure of the experience of Satanism as a context tor meaning emerged. A discussion of the subject's appropriation of murder with Satanism illustrates how the subject imposed a dichotomy of good and bad on his life-world in an attempt to derive meaning from his experience of inadequacy. Involvement with Satanism is meaningful, in that it affords its followers an increased sense of power, a safe environment to explore individuality, shared responsibility associated with exercising free choice, social situatedness and an affirmation of being through an increased awareness of finitude. The research subject experienced committing murder as an act of loyalty to the perceived gains he had been afforded as result of his involvement with Satanism.
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- Date Issued: 2002
Restoring democratic governance in Zimbabwe: a critical investigation of the internet as a possible means of creating new sites of struggle for positive democratic change by Zimbabwean media and activists in Zimbabwe
- Authors: Vennard, Francisca Caroline
- Date: 2002
- Subjects: Zimbabwe -- Politics and government -- 1980- , Internet in publicity , Press and politics -- Zimbabwe , Freedom of the press -- Zimbabwe , Digital media
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2837 , http://hdl.handle.net/10962/d1003047 , Zimbabwe -- Politics and government -- 1980- , Internet in publicity , Press and politics -- Zimbabwe , Freedom of the press -- Zimbabwe , Digital media
- Description: This thesis is a reaction to the state of utter lawlessness and the abuse of human rights by those in power in Zimbabwe over the past two years and it investigates the possibility of restoring democratic governance in that country by increasing the freedom of expression and media freedom, which is considered to be one of the most valuable elements in advancing democratization. Its aim is to establish the Internet as the best means possible to increasing media freedom and creating new ‘sites of struggle’ for activists in a context where the substantive freedom of expression does not exist. This in turn is shown to advance levels of democracy. To this end, the value of the freedom of expression to media freedom and the value of the latter to increasing levels of democracy is developed and the lack of democracy in Zimbabwe at all levels of society is considered. The Internet is seen to increase the freedoms of speech and association in new and interesting ways and it is discussed in various examples in which it has already been instrumental in evading the censorship of the media and increasing the ability of activists to express themselves freely and to organize more efficiently. Finally, the resources that Internet technology makes available to African journalists and activists are considered along with lessons gleaned from international examples of successful Internet use and it is shown to already be of use to Zimbabwean journalists and activists as they create to new cyberspaces in which they can struggle for positive democratic change in Zimbabwe. The Internet is also shown to have tremendous potential for future use in that country.
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- Date Issued: 2002
Can formal language planning link to grassroots cultural initiatives?: an informal investigation
- Authors: Wright, Laurence
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:7041 , http://hdl.handle.net/10962/d1007381
- Description: Formal language planning is inevitably a top-down, highly technical process. Success for such planning would seem to depend on engaging productively with existing or readily developed social motivation within the society. This article reports on an informal investigation into how ordinary language practitioners and cultural workers in South Africa view the possibilities of contributing to the country’s emerging language dispensation, what they regard as their most useful possible contributions, and what they expect from the language planners and ‘government’ in support of South Africa’s Language Policy and Plan.
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- Date Issued: 2002
Action research : exploring the use [of] print media as a resource in the teaching of English as a second language
- Authors: Letsoalo, Matome David
- Date: 2002
- Subjects: Action research in education , English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2376 , http://hdl.handle.net/10962/d1005962 , Action research in education , English language -- Study and teaching -- Foreign speakers
- Description: South African education has been going through a process of transformation: from a traditional, transmission system to one of a more progressive nature. In the new curriculum, Curriculum 2005 anchored on Outcomes-based Education (OBE), focus is laid on critical reflection, innovation and creativity by classroom participants. Learning situations are expected to promote flexibility, co-operation and relevance of teaching/learning materials. This research looks at these aspects in the English Second Language (ESL) situation where print media articles are used as resource. Other than being a rich resource for language, print media texts have been found to be appropriate for this exploration because of their potential to offer opportunities for critical reflection and interaction with authentic issues. Unlike uncritical reliance on textbooks, the proper use of media articles can give the teachers and learners the space to select relevant and exciting materials for their situations. In this study, the research was done through action research where I (the researcher) actually taught the lessons in collaboration with the English teacher. The teaching method was influenced by the Freirean style of Iiberatory teaching where critical reflection, socio-political relevance and co-operation are crucial elements. The action research was done in two cycles. Experiences in the first cycle pointed to, among other aspects, the fact that the learners could not work in a co-operative way as they were not used to it. Addressing this problem consequently became the basis of the second cycle where the skills of co-operative learning were taught before the learners engaged in further lessons. The conclusions drawn from this research point to the importance of the teacher as an agent in the learning process if the demands of progressive and liberatory teaching are to be met. It has thus been concluded that elements such as critical thinking, creativity, flexibility and selection/development of relevant materials presuppose the existence of a well-trained teacher who is skilled and able to make these possible. In the light of my findings, my major recommendation is that teacher development needs to be strengthened so that more emphasis is placed on enhancing the teacher's ability to critique texts and improve his or her own practice, acquiring the skills to teach in a critical way and achieving the learning competencies.
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- Date Issued: 2002
The development assumptions of Botswana television : an assessment
- Authors: Mmusi, Bishy
- Date: 2002
- Subjects: Television -- Social aspects -- Botswana , Botswana -- Social conditions , AIDS (Disease) -- Botswana
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3511 , http://hdl.handle.net/10962/d1007668 , Television -- Social aspects -- Botswana , Botswana -- Social conditions , AIDS (Disease) -- Botswana
- Description: This study researched a project to set up a national television service for Botswana to find out whether the service could be used for rural development generally, and in particular to assist the Ministry of Health to implement its health projects in the rural areas and including the fight against the AIDS disease. It reviews conceptions of development and also analyses various communication models that usefully inform the conceptualisation of a TV service that can contribute to development. The study was done by going through reports of feasibility studies on the project and through letters of official correspondence among officials of the Government of Botswana who debated the subject of whether or not the country should have a national TV service. The reports and correspondence were supplemented with interviews of key people involved in the implementation of the project, as well as interviews of officials of the Ministry of Health. The findings of the study are that the Botswana television service project started and ended on a footing that forgot about television, a medium that is dependent on professional and organisational capacity and purpose, and as a result the project did not take-off. A qualitative method was used as the study required in-depth interviews during which new issues kept on emerging and nothing could be pre-determined because the study took place as the project was being implemented. The study was completed in June 2000, at a point where the project should have been completed but it was discovered that the station could not go on air as a television service had not been conceptualised and there was no management structure in place and the Government of Botswana appealed to the British Government for the staff of the British Broadcasting Corporation to come quickly to Botswana to rescue the project and put it on track, supposedly. The study has concluded that the Botswana television service project became stillborn because there was a lack of professional and intellectual capacity to conceptualise the service, and instead there had been too much concentration on the construction of the TV building and acquisition of equipment.
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- Date Issued: 2002
Psychological resilience: the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts
- Authors: Alexander, Debra Geraldine
- Date: 2002
- Subjects: Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3092 , http://hdl.handle.net/10962/d1003059 , Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Description: This study investigates the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts. The Social Readjustment Rating Scale, the Multidimensional Coping Inventory and the Defense Style Questionnaires were completed by 194 police, ambulance and teaching personnel. A sample of 37 teachers served as a non high risk occupation control group. Descriptive statistics, regression analysis, analysis of variance, analysis of difference and principal component analysis were performed on the data. Results indicated minimal significant between group differences. Within group variances were yielded. A minor relationship between levels of stress and usage of positive and negative mechanisms was observed. The significance of these findings is discussed and recommendations made for further study.
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- Date Issued: 2002
Exploring the perceived value of work as part of psychosocial rehabilitation of the state patient : Komani Hospital, Queenstown
- Authors: Crocker, Ann Petro
- Date: 2002
- Subjects: Work -- Psychological aspects Mentally ill -- Attitudes
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:5953 , http://hdl.handle.net/10962/d1007464
- Description: During the research an attempt was made to gain an understanding of the perceived value of work in psychosocial rehabilitation with the Sate patient at Komani Hospital. The respondents' motivation to work and what they gain from working, was investigated, as well as the experience of the nonworking respondents and their motivation not to work. To achieve this, ten respondents who were working and ten respondents who were not working, were interviewed. This study involves only a limited number of State patients at Komani Hospital and therefore findings cannot be generalised and also because the study was done at one Hospital only. A literature study was undertaken during which it was evident that work as part of vocational rehabilitation contributed to the well being of the mentally disabled person. It was also stated in the literature that the disabled person must be actively involved in his/her own rehabilitation planning and that the person must make conscious decisions to move away from the "sick" role and participate in his/her rehabilitation process. Interview schedules were developed. Response received from the twenty participants was analysed. The overall findings of the study showed that the majority of respondents who were working, were motivated by money. The fact that the respondents work from Hospital and therefore disrupt the Hospital routine, work with abled co-workers and feeling needed by the factory where they are employed. also emphasised the respondents' motivation to keep on working. The findings of the study with the non-working group showed that some respondents want to work, but there are not enough work opportunities available in and from Hospital. The non-working respondents are not interested in working at the occupational therapy department because the pay patients get for work done at the department is too little, and therefore they reject the work there. Some respondents do not want to work. whether work is available or not. The non-working group is largely dependent on staff and co-patients for an income, or tobacco. The predominant activity of the non-working group of respondents during the day, as well as that of the majority of the working group respondents during weekends was sleeping, talking to friends, and smoking. The research findings, conclusions and recommendations could contribute to a better understanding of patients and the value of work for the patient in a Psychiatric Hospital.
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- Date Issued: 2002
Diamondback Moth, Plutella xylostella (L.), (Lepidoptera: Plutellidae ), and Other Insects of Canola, Brassica napus L., in Gauteng Province, South Africa
- Authors: Mosiane, M S
- Date: 2002
- Subjects: Plutellidae , Plutellidae -- South Africa -- Gauteng , Rape (Plant) -- South Africa -- Gauteng , Canola , Plant parasites
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5937 , http://hdl.handle.net/10962/d1018250
- Description: Canola, Brassics napus L. is a relatively new crop in South Africa. Insect pests have not yet been a major problem, but the notorious brassica specialist, diamondback moth (DBM), Plutella xylostella (L.) (Plutellidae) is establishing itself as a serious pest of this crop. DBM is the most important insect pest of plants from the family Brassicaceae throughout the world. It has developed resistance to all chemical pesticides used against it in the field and to toxins of the bacterium Bacillus thuringiensis. The pest status of DBM in South Africa is lower than in other countries with similar climates. However, due to indiscriminate use of pesticides, local populations of DBM are showing signs of resistance. An initial survey has indicated that in addition to DBM, canola is also attacked by aphids, Myzus persicae (Sulzer), Brevicoryne brassicae (L.), Lipaphis e1ysimi (Kaltenbach), (Aphiade), thrips, Thrips tabaci (Lindeman) and other pests mostly brassica specialists. The study was initiated to determine the composition of the community of insects found on canola, the seasonal phenology of DBM populations in canola, and the composition, relative abundance and seasonality of its parasitoids. Monitoring of the insects was carried out at weekly intervals for three years at Rietondale and Bapsfontein in Gauteng province of South Africa. Berlese funnels have been found to be useful in extracting insects from plants, and were used to indicate the presence ofDBM larvae and other insects found on canola. Adults of DBM were monitored with synthetic pheromone traps; larval and pupal populations were monitored by scouting canola plants. Samples of larvae, pupae and parasitoid cocoons were brought into the laboratory. Parasitoids that emerged were identified and their incidence recorded. Monolepta cf bifasciata (Chrysomelidae) and Listroderes costrirostris (Schoener) (Curculionidae) were the most abundant of the coleopteran pests. (DBM) and Heliothis armigera (H.) (Noctuidae) were most abundant lepidopteran pests of Canola. There was a high proportion of first and second instar larvae as indicated by the results of the Berlese funnels as compared to visual scouting in Bapsfontein. From May to August the infestation level of DBM was high, reaching the maximum of 0.25 larvae per plant in June 1996, then declined and remained low for the rest of the season in Rietondale. From September to December for all three years of the study, the population levels Of DBM were high, reaching a maximum of 9.6larvae per plant in September 1997, and remained low from January to August in Bapsfontein. The number of adult moths per trap per week ranged from 0 to 91 in Rietondale, peaking in January 1996 and September 1997. There was no correlation between infestation levels and the pheromone trap catches. In contrast to Rietondale, there was a high correlation between pheromone trap catches and subsequent larval infestations at Bapsfontein. Although DBM infestation levels were generally low, parasitism levels often reached 100% caused by a complex of parasitoids. During the period of study, the following hymenopteran parasitoids were recorded: Cotesia plutellae (Kurdjumov) and Apanteles eriophyes (Nixon), Braconidae), both larval parasitoids, Diadegma mollipla (Holmgren) (Ichneumonidae), and Oomyzus sokolowskii (Kurdjumov) (Eulophidae), larval-pupal parasitoids, Diadromus collaris (Gravenhorst) (Ichneumonidae) pupal parasitoid, and the hyperparasitoids Mesochorus sp. (Ichneumonidae) and Pteromalus sp. (Pteromalidae). Cotesia plutellae was the most abundant parasitoid occurring throughout the year..
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- Date Issued: 2002
Catalytic behaviour of metallophthalocyanines towards the detection of nitric oxide
- Authors: Vilakazi, Lea Sibulelo
- Date: 2002
- Subjects: Electrochemistry Nitric oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4418 , http://hdl.handle.net/10962/d1006852
- Description: Electrocatalytic reduction and oxidation of nitric oxide (NO) using cobalt phthalocyanine complexes have been studied and compared to vitamin B₁₂ and other metallophthalocyanine (MPc) complexes. Modifying a glassy carbon electrode with these complexes resulted in improved sensitivity of the electrode allowing detection of NO to 10⁻⁹ mol dm⁻³. The mechanisms of catalysis were studied. Electrocatalysis of NO involves coordination of NO to the MPc complex. Hence catalytic activity is affected by the nature of the metal center. However coordination of NO to the MPc complex has to be reversible to eliminate poisoning of the electrode. Though FePc gave the best sensitivity and lowered the reduction potential more than CoPc, the strong Fe-NO bond resulted in the poisoning of the electrode hence, rendering the electrode unstable. Rate constants for NO coordination to the MPc complexes were studied. These rates were smaller than the studied NO porphyrin coordination rates. Electrocatalytic reduction of NO using MPc complexes involves a transfer of an electron from the metal center to the NO ligand. Hence, substitution of electron-donating grohps on the cobalt pthalocyanine complex resulted in improved sensitivity and catalytic activity. A CoPc modified microelectrode (11μm) was used to monitor NO in human blood components and to detect NO in a rat brain. Detections of NO were also done in aqueous solutions in the presence of interfering species such as dopamine and serotonin. An interaction between NO and serotonin was observed.
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- Date Issued: 2002
Biosulphidogenic hydrolysis of lignin and lignin model compounds
- Authors: Madikane, Mzekelo
- Date: 2002
- Subjects: Lignin Lignin -- Biodegradation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3917 , http://hdl.handle.net/10962/d1003976
- Description: Lignin degradation under biosulphidogenic conditions has not been extensively reported in the literature. Although aerobic degradation of lignin is well documented, anaerobic biodegradation has focused mainly on methanogenic systems with biosulphidogenic systems receiving less attention. Sulphate reducing bacteria are known to generate moderately high levels of both sulphide and alkalinity at room temperatures, and these conditions draw some comparison with the Kraft pulping process. In the Kraft pulping process, lignin is degraded chemically at ±170°C under high sulphide and alkaline conditions and may provide a model for understanding biosulphidogenic lignin degrading activity. The aim of this study was to investigate the biosulphidogenic hydrolysis of lignin within the context of the chemical and biological conditions generated by a mixed sulphate reducing bacteria consortia. Bioreactor studies with a mixed sulphate reducing consortia and pine wood powder (both untreated and depectinated) resulted in the generation of comparable levels of sulphide and alkalinity used in the chemical hydrolysis studies. Aromatic compound yields were between 20 to 50% of the chemical hydrolysis studies. This fluctuation may have been due to the utilization of these aromatic compounds as electron donors by the sulphate reducing consortia as evidenced by the high rate of sulphate reduction in both the untreated and depectinated wood bioreactors. Biodegradation of lignin model compounds was investigated in order to elucidate lignin degradation mechanisms. Both mono-aromatic and dimeric lignin model compounds were used as electron donors and carbon sources for the mixed sulphate reducing consortia. Biodegradation and mass spectrometer analysis of mono-aromatic compounds, ferulic acid and ferulic acid ethyl ester resulted in the production of intermediates such as catechol, cyclohexane carboxylic acid and adipic acid. These intermediates were also observed in the degradation of dimeric ferulic acid. Biodegradation of salicin resulted in the production of salicyl alcohol, ortho-cresol and acetate. Biodegradation of benzylic ether resulted in the production of vanillin and acetate as end products. The results of these studies provide evidence for a biosulphidogenic hydrolysis of lignin, and also the utilisation of lignin-derived aromatic compounds as electron donor sources, by a mixed sulphate reducing consortia.
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- Date Issued: 2002
A taxonomic revision of the genus Bergeranthus Schwantes (Mesembryanthemaceae) in South Africa
- Authors: Dold, Anthony P
- Date: 2002
- Subjects: Aizoaceae -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4248 , http://hdl.handle.net/10962/d1007481 , Aizoaceae -- South Africa
- Description: The genus Bergeranthus Schwantes comprises ten species ofleaf-succulent Mesembryanthemaceae that are centred in the Albany centre of endemism and restricted to the Eastern Cape Province of South Africa. No taxonomic revision of the genus, or key to the species of Bergeranthus, has been undertaken since its description by Schwantes in 1926. The species concepts are mostly based on single, or at best severaL cultivated plants and are notoriously narrow and in some cases incorrect. Louisa Bolus described five of the ten currently recognized species of Bergeranthus (as well as B. cookii, B.firmus, B. glenensis, B.jamesii, and B. longisepalus) from cultivated plants that she had never seen in the wild. This narrow species concept, compounded by morphological change that occurs in response to environmental factors, presents an assemblage of ill-defmed and poorly known taxa that have been prioritised for taxonomic attention by various authors. Furthermore, the generic delimitation of Bergeranthus with the closely related genera Rhombophyllum and Hereroa is unclear and requires attention before generic revisions are attempted for all three genera. The taxonomic revision presented here is based on a study of 210 wild populations of Bergeranthus as well as cultivated representatives of these and 135 herbarium specimens. A phenetic analysis based on 36 vegetative characters was initially used to delimit taxa. Thereafter sixty-three macro- and micro-morphological characters were critically assessed for the purposes of species delimitation, amendment of existing species descriptions and the description of two new species. Macromorphological characters examined included rootstock, leaf(36), inflorescence, floral (nine), fruit (nine), seed germination and seedling characters. Micro-morphological characters examined included leaf anatomy, leaf epidermal wax layer, anther shape and point of adherence, pollen and seed characters. This revision reduces two species into synonymy and two new species, B. albomarginatus and B. nanus, are described. Existing species descriptions are improved and all species are illustrated. A key to species is provided. The reproductive biology, ecology, phytogeography and distribution data of the genus are discussed towards an improved understanding of the genus. The generic delimitation of Bergeranthus and its closest relatives, Rhombophyllum and Hereroa, are discussed based on an examination of 25 morphological characters and two phenological characters and a provisional key to genera is provided. A phylogenetic analysis of all 10 species of Bergeranthus, both species of Rhombophyllum and a single species of Hereroa (H. granulata) was undertaken to support species and generic delimitation.
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- Date Issued: 2002
Synthesis, photophysical and photochemical studies of germanium and tin phthalocyanine complexes
- Authors: Maree, Suzanne , Phillips, David , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/289667 , vital:56661 , xlink:href="https://doi.org/10.1142/S108842460200004X"
- Description: This work reports on the synthesis of tin and germanium phthalocyanine complexes containing phenoxy and substituted phenoxy groups as phthalocyanine ring substituents. The compounds studied are: dichlorogermanium phthalocyanine complexes containing eight phenoxy (4a), o-methyl phenoxy (4b) or estrone (4c) groups on the ring. The corresponding dichlorotin complexes (5a, 5b and 5c) and diiodotin complex (6a) were also investigated, as well as diestrone phthalocyaninato tin (7). Germanium octaphenoxy phthalocyanine complexes undergo phototransformation rather than direct photobleaching, whereas tin octaphenoxy phthalocyanine complexes undergo a photobleaching process, which is mediated by photoreduction of the phthalocyanine ring. Tin octaphenoxy phthalocyanine complexes gave higher ΦΔ values than the corresponding germanium complexes. Also tin phthalocyanine complexes containing an unsubstituted ring gave higher ΦΔ values than the corresponding octaphenoxy substituted complexes. The triplet quantum yields increased with the increase in electron-donating power of the ring substituents.
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- Date Issued: 2002
The influence of structure, density and direct use benefits on the harvesting of trees in the rural village of Pikoi, Eastern Cape, South Africa
- Authors: Motinyane, Teboho R
- Date: 2002
- Subjects: Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4771 , http://hdl.handle.net/10962/d1007705 , Deforestation -- Control -- South Africa -- Eastern Cape , Deforestation -- South Africa -- Eastern Cape , Fuelwood consumption -- South Africa -- Eastern Cape , Trees -- South Africa -- Eastern Cape
- Description: The people of Pikoli in the Peddie district of the Eastern Cape are mostly unemployed and earn most of their income from old-age allowances. The place is remote and 'modern' amenities such as paraffin and petroleum gas are expensive. Electricity and transport are unavailable. There is heavy reliance on woody plants for fuel and for materials for construction and fencing and to some extent medicinal and ritual uses. Indigenous trees in this rural area are threatened by over-utilisation and the absence of clear government management policies. The over-utilisation of these resources is leading to deforestation. It was proposed at the beginning of this study that people who harvest trees cause similar results to the piosphere effect caused by the herbivores on the rangeland. Ecological-economic analysis was performed to find a common ground between the people's income and needs so that effective sustainable management strategies can be developed. A combination of semi-structured interviews, direct observations and ecological surveys were used to gather information about: Tree species used, and for what purpose in Pikoli; Individual tree species preference by inhabitants; Change in tree density in response to changes in utilisation intensity at varying distances away from the village; The local direct use benefits inhabitants derive from utilising indigenous tree resources. The study showed that the people of Pikoli use a variety of 23 indigenous trees and that they have marked preferences regarding the tree species they use for fuelwood and construction purposes. Although Ptaeroxylon obliquum is a highly preferred species for fuelwood and construction, its popularity can also be linked to its high relative abundance in this area. Other species such Maytenus undata and Pappea capensis are also highly preferred although they are harvested at much greater distances from thecentre of the village. Change in individual tree density in response to changes in utilisation intensity at varying distances away from the village showed clearly that a piosphere effect also applies to human harvesting. The average number of individual trees closer (1 200 m) to the village centre was 2 trees per 100 m², and their numbers increase to approximately 35 trees per 100 m² at a distance of about 3 000 m from the village centre. The study reports on the direct use benefits derived by the people of Pikoli from harvesting tree resources. The average total net value of trees harvested for fuelwood was R4089.09 (US$ 359.01) per household per annum. The value of tree resources harvested represents a large percentage of average households' annual income. Therefore, the economic benefits households derive from utilising tree resources are high. Indigenous tree resource use in this rural village seems to be unsustainable and the inhabitants seem to be aware of it. However, they have few alternatives. Their economic conditions do not allow them to afford alternative resources available in the formal market.
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- Date Issued: 2002
Building project management within financial institutions, a comparative assessment
- Authors: Van Tonder, Anthony David
- Date: 2002
- Subjects: Project management , Financial institutions -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10893 , http://hdl.handle.net/10948/79 , Project management , Financial institutions -- Management
- Description: The expenditure by financial institutions in South Africa on building projects could conservatively be estimated to total in the region of a billion rand per annum. It is surprising, given the amount of money being spent that there is currently no co-operation between the various financial institutions in the field of building project management. The research in this study found that most financial institutions were not taking into account all the costs and benefits when undertaking a project. When a project is undertaken in this manner, the viability analysis would not be a true reflection of the project being undertaken. The areas which were not taken into account when undertaking a project were the indirect project costs, which included costs like the project management staff themselves. An exception to this was First National Bank Metropolitan Delivery. They followed an outsourcing strategy in terms of their building project management function and the cost of this was known and added into the project cost. In terms of the benefits, this study found that the financial institutions do not take the intangible benefits into account. They do not consider the long term benefits which will be derived as a result of the implementation of a project. Arriving at a model which takes into account these factors, would provide material for a Doctorate thesis.
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- Date Issued: 2002
The development of an operations strategy for Eissmann South Africa that addresses market requirements and the needs of its customers
- Authors: Richards, Scott
- Date: 2002
- Subjects: Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10899 , http://hdl.handle.net/10948/88 , Production management -- South Africa , Eissmmann South Africa (Firm) Customer services , Customer services -- Management
- Description: With global competition becoming a key concept in the majority of companies worldwide, it is necessary for organisations to develop operations strategies that enable them to meet their customers‘ needs. Organisations will never be capable of reaching future goals without their customers. For this reason it is imperative for organisations to identify what competitive factors are required by the market, and which performance objectives are needed in order to increase the competitiveness of the organisation. In this research, Chapters 1 and 2 were used to identify the main and subproblems of the research, to delimit the research and to provide literature background to operations strategies and related operations topics. The empirical study in Chapter 3 was used to gather information pertaining to the specific requirements of ESA’s customers, and the operations performanceof ESA. Chapter 4 was used to analyse the data gathered from the empirical study. From this analysis it was possible for the researcher to identify the specific requirements of ESA’s customers and the operations performance of ESA. Chapter 5 was used to provide recommendations to bridge the performance gap between the customer requirements and the operations performance of ESA. By effectively implementing all of the recommendations suggested in this research, ESA will be able to improve its operation performance and meet the specific requirements of its market and its customers.
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- Date Issued: 2002