The geology, petrology and geochemistry of the mineralization and hydrothermal alteration at Ongeama, Ongombo and Matchless West Extension, Namibia
- Authors: Moroni, Marilena
- Date: 1991
- Subjects: Geology -- Namibia , Petrology -- Namibia , Geochemistry -- Namibia
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5045 , http://hdl.handle.net/10962/d1007693 , Geology -- Namibia , Petrology -- Namibia , Geochemistry -- Namibia
- Description: The Matchless Amphibolite Belt (Damara Orogen, Namibia) hosts several volcanogenic-exhalative, sediment-hosted stratiform cupriferous pyrite deposits. These are thought to be related to submarine volcanism during the early evolutionary stages of a narrow Damaran ocean, the Matchless Trough. The mineralized bodies examined (Ongeama, Ongombo and Matchless West Extension) are deformed and metamorphosed to low-medium grade (greenschist-amphibolite facies). They are associated with metapelite and amphibolite country rocks, and crop out as prominent limonite-rich gossans. The elongated shape of the sulphide bodies suggests a structural control. The mineralization normally consists of a variably developed massive sulphide portion, either quartz-, talc- or amphibole-bearing, and a stratigraphically overlying, extensive horizon of sulphide- and baryte-bearing exhalite (magnetite quartzite and less common talc- and actinolite-bearing schists). Lateral and vertical mineralogical changes within the mineralization match with significant variations in the element distribution. A metamorphosed and deformed alteration pipe, indicating the position of the fluid conduit, can be recognized in association with some ore bodies. The formation of quartz-muscovite and chlorite alteration envelopes (Ongeama, Matchless West Extension) and the presence of subtle mineralogical changes (Ongombo) in the immediate wallrocks, accompanied by extensive redistribution, leaching and introduction of elements from outside, suggest the hydrothermal metasomatic origin of the alteration zones. Element zoning within the mineralized bodies can be related to the original position of the vent, possibly coinciding with the intersection of the axis of the alteration pipe with the sulphide body. Cu, Zn, Au (pro parte) and Mo are enriched proximal to the vent, whereas Pb, Ba, Mn, Ag, Au, Sn, Bi and W enrichment characterizes the distal facies of the mineralization. In spite of the obliterating and disrupting effects of the regional dynamo-metamorphism, the element distribution within the mineralization and alteration zones examined is comparable with the geochemical trends observed in present-day mineralizing systems in early- stage oceanic environments (e.g. Guaymas Basin). During exploration for blind volcanogenic mineralization, the detection of hydrothermally altered rocks is fundamental in indicating the proximity to the mineralization. The localization of the alteration zone is also important in the interpretation of the regional geology of the explored area: in deformed terrains the assessment of the stratigraphic position of the alteration zone, relative to the mineralization, helps in establishing the polarity of the sequence.
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- Date Issued: 1991
The pineal gland as a model to elucidate the primary mode of action of sympathoactive agents
- Authors: Welman, Alan David
- Date: 1991
- Subjects: Pineal gland , Cythochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3876 , http://hdl.handle.net/10962/d1001610
- Description: An attempt was made to use the pineal gland as a model for the study of the primary mode of action of sympathoactive agents. Two drugs were investigated, viz. alpha-methyldopa and ephedrine whose mode of action is not entirely clear. Organ cultures of pineal glands from rats treated chronically with alpha-methyldopa showed enhanced conversion of radioactive serotonin to melatonin (aMT) , as well as its precursor Nacetylserotonin (aHT). This treatment was also found to raise Nacetyltransferase (NAT) activity. These increases associated with alpha-methyldopa treatment were further enhanced by the beta-adrenergic agonist, isoproterenol, suggesting a supersensitivity-type effect occurring at the level of the beta-receptor. A subsequent binding study, however, showed a decrease in beta-receptor binding with exposure to alpha-methyldopa, providing mitigating evidence against the occurrence of a supersensitivity phenomenon. It is possible that a metabolite of alpha-methyldopa acts as an alpha 1 and beta-adrenergic agonist, resulting in greater melatonin (aMT) and N-acetylserotonin (aHT) synthesis than by a beta-adrenergic agonist, isoproterenol. Combined treatment of pineals with alpha-methyldopa and an alphareceptor blocker, phentolamine, resulted in melatonin (aMT) , Nacetylserotonin (aHT) , and N-acetyltransferase (NAT) activity levels which were lower than those obtained with alpha-methyldopa treatment alone, thus confirming the alpha-adrenergic activity of the metabolite of alpha-methyldopa. Additional pineal metabolites were isolated and measured simultaneously in the organ culture experiments. Organ cultures of rat pineal glands treated with ephedrine showed raised levels of melatonin (aMT) and N-acetylserotonin (aHT). Treatment with ephedrine also produced raised N-acetyltransferase activity. A further enhancement of these parameters was induced by norepinephrine, suggesting a supersensitivity-type effect occurring at the level of the beta-adrenergic receptor. Rats were treated with reserpine (a norepinephrine depleter) and the pineals exposed to ephedrine. Endogenous norepinephrine normally released by the action of ephedrine was thus absent, and under these conditions, levels of melatonin (aMT) and N-acetylserotonin (aHT) were reduced. N-acetyltransferase (NAT) activity was also reduced, but maintained levels pointing to substantial adrenergic activity of ephedrine as well as norepinephrine released by virtue of the drug's action. A subsequent binding study showed a decrease in beta-adrenergic receptor binding with exposure to ephedrine and a further decrease in ephedrine treated pineals from reserpine treated rats, thus ruling out the occurrence of a supersensitivity phenomenon. It is possible that both ephedrine and released norepinephrine have alpha- and beta-receptor activity. Additional pineal metabolites were isolated and measured in the organ culture experiments. A 16-hour time profile of the production of melatonin (aMT) and N-acetylserotonin (aHT) with norepinephrine and ephedrine treatment provided useful information regarding the course of action of the two agents. A pineal cell-culture system was developed and exposed to ephedrine and norepinephrine. N-acetyltransferase (NAT) activity levels measured after exposure to these agents were raised, confirming the adrenergic activity of both in the model. Finally, an HPLC system coupled to a UV detector was used in an attempt to measure melatonin (aMT) extracted from pineal organ culture media. The results showed that melatonin could be measured by this method, however, a more sensitive detection system was recommended for future work.
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- Date Issued: 1991
An investigation into pupils' knowledge of and attitudes towards AIDS : a survey of four private schools
- Authors: Robinson, Margaret
- Date: 1991
- Subjects: AIDS (Disease) -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1348 , http://hdl.handle.net/10962/d1001414
- Description: Because of the extent and immediacy of the problem of AIDS in the RSA and because this disease, which is mainly transmitted by voluntary human behaviour, has no cure, the need for educational programmes to curtail the spread of AIDS is seen as of prime importance in the RSA. At present there is little published research about the levels of knowledge of AIDS attained by pupils in junior and senior schools, nor of the attitudes they have towards the disease. It was felt that without this information, it would be difficult to develop appropriate AIDS education programmes. In this research, questionnaires were administered to investigate the knowledge of and attitudes towards the acquired immunodeficiency syndrome - (AIDS) - of the standards 5, 7 and 9 pupils at four private schools. These three age groups were chosen in order to look at the possible effects of the maturation process on these pupils' perceptions of AIDS. A questionnaire was also completed by selected school personnel to provide background information on any existing AIDS education in the schools. A pilot study was carried out with a small group of pupils in order to establish the areas of concern being expressed by senior school pupils. The results of the survey have shown that while there is a gradation in the knowledge levels of the pupils in standards 5, 7 and 9, there is a need for more intensive teaching of AlDS at or before the transition from junior to senior school. That the pupils perceive a need for school-based education, particularly in order to acquire knowledge of prevention strategies, was evident. The attitudes of the majority of the pupils towards AIDS sufferers were found to be tolerant or circumspect, although there was evidence of intolerance from some quarters. The fears of the pupils were found to stem largely from the unique characteristics of the disease and a lack of knowledge of how to protect themselves against it. In developing guidelines for a programme of AIDS education for the South African schools, the programmes and interventions currently operative in the USA, Great Britain, Europe and two African countries were considered. This research has raised a number of questions, the answers to which will he important in the development of future programmes of AIDS education
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- Date Issued: 1991
Evaluating an English department: the use of illuminative evaluation procedures in descriptive and diagnostic analysis of English teaching programmes in high schools
- Authors: Thorpe, Robert Nicholas
- Date: 1991
- Subjects: English language -- Study and teaching (Secondary) -- South Africa English language -- Study and teaching (Secondary) -- Evaluation
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1522 , http://hdl.handle.net/10962/d1003404
- Description: To evaluate what is actually happening within a High School subject curriculum, the annual parade of marks, percentages and symbol distributions is not by itself adequate, especially in assessing progress towards such English syllabus goals as: That pupils expand their experience of life, gain empathetic understanding of people and develop moral awareness. (3.1. 4 HG) How too, from examination results alone, can a subject head of English assess the success of his objective "to woo his pupils into the reading habit"? (School 1: Goals 1988) Decisions on English department policy and procedures are frequently based on personal hunches and examination results. Few subject departments engage in proper evaluations of their curricula to support decisions made, or to impart meaning upon the countless daily transactions between child and adult, individual and institution in the learning process. This study demonstrates the efficacy of "illuminative evaluation" techniques in opening out an educational innovation (1986 First Language English syllabi of the Cape Education Department) at two High Schools for comment and appraisal. The array of information gathered should be useful in planning and implementing further curricula initiatives. The inherent flexibility of illuminative evaluation procedures and their freedom from large-scale data base requirements needed for 'scientific' models of evaluation are advantageous in investigating the untidy complexities of English teaching. Both 'closed' and 'open' response questionnaires, interviews, and perusal of relevant documents informed the researcher of the views of pupils, parents, English teachers, other subject heads, the two school principals and the education authorities on what waS and ought to be happening in English classes. From the considerable array of information generated, the distress of conscientious English teachers facing unreasonable work-loads emerged clearly. Such teachers are likely to occupy key roles in the non-racial state schools of the future and cannot be regarded as expendable. 'Open schools' present new challenges to existing curricula and the position of English may prove to be critical. Thus it is submitted that English subject heads should be concerned with evaluating their departments so that informed decisions can be taken on future directions. Illuminative evaluation is demonstrably useful in such analyses.
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- Date Issued: 1991
The effect of teaching text organisation on reading in English as a second language
- Authors: Silburn, Gail Deirdre
- Date: 1991
- Subjects: English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1372 , http://hdl.handle.net/10962/d1001438
- Description: This research investigated the effect of teaching text organisation on reading in English second language to schoolgirls. All subjects underwent a training programme of five one-hour sessions on consecutive school days. The experimental group were trained in the use and recognition of top-level organisation as a reading strategy, based on work done by Bartlett (1978) and Carrell (1985). The control group were trained in unrelated grammar exercises. A pre-test was administered to each group before their programme began. Post-test 1 was administered immediately after the training was completed, and Post-test 2, three weeks later. These tests required a written recall of two passages once they had been read, and an answer to a question on their organisation. The null hypotheses stated that the experimental group's training in the use and recognition of top-level organisation as a reading strategy would make no difference in their ability to read and recall information or to recognise and use top-level organisation in their recalls. For the quantity of information recalled, no differences were found in the Pre-test and Post-test 1; a statistically significant difference was found in Post-test 2 in favour of the experimental group. For the quality of information recalled, the control group remembered more top-level idea units in the Pre-test; there was no difference in Post-test 1; the experimental group did better in three out of five levels in Post-test 2. There was no difference in the Pretest in either group's use of the passage's top-level organisation to structure recalls, but the experimental group did better in both post-tests. The control group did better in the Pre-test in recognising the passage's top-level organisation, but the experimental group did better in both post-tests. The null hypotheses were rejected as the experimental training made a difference, although this difference only became apparent three weeks later, and not immediately after the training. The experimental group's nullifying the control group's Pre-test advantage in Post-test 1 and surpassing it in Post-test 2, powerfully supports Bartlett's and Carrell's findings that teaching the strategy did make a difference and that this effect could be maintained over three weeks
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- Date Issued: 1991
The development, pursuit and maintenance of a South African Antarctic policy : 1926-1988
- Authors: Laverde, René
- Date: 1991
- Subjects: Antarctic Treaty -- (1959) , Antarctica -- History , South Africa -- Foreign relations -- Antarctica
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2523 , http://hdl.handle.net/10962/d1001852
- Description: Connections between South Africa and Antarctica can be traced as far back as the 1700s when European expeditions in search of the southern continent used Cape Town (and later Simonstown) as a base of operation. This link expanded considerably after formal British acquisition of the Cape of Good Hope in 1815, yet it was not until 1926 that an actual South African policy towards the Antarctic began to materialize. Once this policy was established it continued to be characterized by procrastination as well as resistance both from within and without South Africa. The history of South Africa's Antarctic policy can be divided into five periods: first, the commencement of the policy (focusing primarily on economic interests), 1926-1939; second, the pursuit of interests through the policy (focusing on political interests), 1944- 1958; third, the entrenchment of South Africa's interests in the Antarctic (by securing South Africa's position within the Antarctic Treaty System), 1958-1960; fourth, the expansion of and foreign assault on the policy (under the auspices of the Antarctic Treaty System), 1960-1988; and fifth, the defence of and future prospects for the policy (from United Nation's calls for South Africa's exclusion from the Antarctic Treaty System), since 1982. While resistance from inside and outside the government during the first two periods resulted from inadequacies in the South African Antarctic policy itself, resistance in the final two periods has centred upon non-Antarctic issues. As South Africa has faced ever-increasing exclusion from international governmental organizations over opposition to Its apartheid policies, organizations such as the Antarctic Treaty Organization have inevitably been drawn into the debate. As a result, the Consultative Parties of the Antarctic Treaty (of which South Africa is one of the original twelve) have been forced to deal with the following question: to what extent will political issues outside the scope of the management policies of the Antarctic Treaty Organization be allowed to affect the functioning of the Antarctic Treaty System? While the Consultative Parties continue to ponder this and the fact that South Africa's Consultative Status has become the most divisive factor within the Antarctic Treaty System, no final solutions to these issues appear likely before 1991.
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- Date Issued: 1991
An investigation of the significance of learned helplessness on membership participation in co-operative movements
- Authors: Norman, Paul Deon
- Date: 1991
- Subjects: Learned helplessness , Psychology , Black people -- South Africa , Attributional Style Questionnaire , Partician Index , Co-operatives , Helplessness (Psychology) , Black people -- Psychology
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2895 , http://hdl.handle.net/10962/d1002059
- Description: In this study the psychological phenomenon of learned helplessness is investigated to determine its significance as a characteristic of members of progressive co-operatives within the South African context. Most of the members of these co-operatives are black South Africans. It is argued that because of the country's racial policy, many of the members have become accustomed to a passive response to events in their lives and this gives rise to their failure to utilise the freedom and opportunities of the co-operative structure. The researcher hypothesises that this passive response could be explained in terms of a high level of learned helplessness among co-operative members. Two hypotheses are investigated in this study: Hypothesis 1: Passive co-operative members will have higher levels of learned helplessness than active members. Hypothesis 2:The level of learned helplessness decreases as the length of co-operative members involvement increases. Data collection for this study was carried out by combining a personal interview and a standardised questionnaire (the Attributional Style Questionnaire). To distinguish between the passive and active members, a Participation Index was constructed. The ASQ was translated into Xhosa, adapted for the sample and two translators were employed to conduct the interviews in Xhosa. The sample consisted of 50 black South Africans, many with limited education and was drawn from six co-operatives in the Eastern Cape. No significant differences were found between the active and passive groups in terms of their levels of learned helplessness. Furthermore, the length of involvement in the co-operative had no effect on the level of learned helplessness. No support was found therefore for Hypothesis l and 2. A significant difference, however, was found between active and passive members and the number of months of involvement. This suggests that the length of involvement has an effect on how active members will be in the co-operative. The results of this study indicate that generally the sample does not suffer from learned helplessness. It is argued that Hypothesis 2 is not supported due to confounding variables. The study raises many doubts as to the reliability of the ASQ and the Participation Index used in the study.
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- Date Issued: 1991
Gold mineralization in an archaean granite-greenstone remnant west of Melmoth, Natal ore genesis and implications for exploration
- Authors: Bullen, Warwick David
- Date: 1991
- Subjects: Gold ores -- Geology -- South Africa , Greenstone belts -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4967 , http://hdl.handle.net/10962/d1005579 , Gold ores -- Geology -- South Africa , Greenstone belts -- South Africa -- KwaZulu-Natal
- Description: The previously undifferentiated, "Melmoth Granite-Greenstone Remnant" (MGGR¹) crops out over an area of about 360 km² in northern Natal, South Africa. The greenstone sequence is comprised mainly of mafic metalavas with lesser serpentinite, talc schist, dacitic tuff, quartz-muscovite schist, quartzite and calc-silicate rocks. The greenstones are intruded by syntectonic trondhjemitic gneisses, late-tectonic granodioritic gneisses and post-tectonic granite dykes. Four phases of deformation and metamorphism are recognized. Epigenetic, disseminated and quartz vein-hosted gold mineralization is associated with D₂ shearing - a positive correlation existing between the intensity of the shearing, the thickness of the shear zone and the grade of ore it contains. Auriferous quartz veins are distinguished from an earlier generation of barren vein quartz on the basis of mineralogy, texture and relationship to the s-fabric. The mineralization occurs in zones of dilation associated with shear zone refraction. Associated wall rock alteration includes sericitization, argillization and chloritization. An ore genesis model based on the aforementioned parameters, is proposed. Finally, an exploration programme has been devised in order to locate undiscovered gold deposits in the MGGR. The programme could probably be applied, with minor modifications, to shear zone-hosted gold deposits in other granite-greenstone remnants in northern Natal. ¹- Name suggested by writer.
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- Date Issued: 1991
An investigation of the romantic ballet in its sociocultural context in Paris and London, 1830 to 1850
- Authors: Osborne, Jane
- Date: 1991
- Subjects: Ballet -- France -- Paris , Ballet -- England -- London , Ballet -- History -- 19th century , Ballet -- Sociological aspects
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2126 , http://hdl.handle.net/10962/d1002028
- Description: Historians have made a considerable contribution to the study of the Romantic ballet in terms of chronological development, the Romantic movement in the arts and the contribution of specific dancers and choreographers; very little research has been attempted to date on the interrelationship between the dance form and the wide range of human experience of the period. This holistic approach provides insight into form, content and stagecraft; political, economic and social influences; the prevailing artistic aesthetic and cultural climate; sex, gender and class issues; and the priorities, value system and nuances of the times. Recent work by historians and social scientists (eg Brinson 1981, Adshead 1983, Spencer 1985, Hanna 1988, Garafola 1989) advocates a recognition of the role of social and cultural systems in the evaluation of dance. This approach further ackowledges the equal status of all cultures, and has opened up areas of African performing dance in cultural systems outside the west. My parallel investigation of the gumboot dance in its South African context, which appears in Appendix B, provides an example. The first half of the nineteenth century was characterized by the disruptive beginnings of the emergent industrial world, centred in Paris and London; and the Romantic ballet tradition reached its greatest heights at this time. Chapter one establishes the political, economic, social and artistic environment, and identifies middle class dominance as a key factor. Chapters two and three focus primarily on the three great ballets of the age, La Sylphide, 1832, Giselie, 1841, and Pas de Quatre, 1845, as expressions of the essential duality of the times, and of Romantic synaesthesia in the arts, which enabled them to transcend the pedestrian bourgeois materialism of faciliatators and audience. Chapter four examines the images of the idealized ballerina and the 'Victorian' middle class woman in relation to bourgeois male attitudes to female sexuality, gender and class. The conclusion sums up the themes of duality, middle class influence, and the Romantic aesthetic, and discusses the prevalent notion that this period was identified as a 'golden age' of the Romantic ballet.
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- Date Issued: 1991
Land expropriation and labour extraction under Cape colonial rule : the war of 1835 and the "emancipation" of the Fingo
- Authors: Webster, Alan Charles
- Date: 1991
- Subjects: Ayliff, John, 1797-1862 , Fingo (African people) -- History , Frontier War, 1834-1835 , Cape of Good Hope (South Africa) -- History -- 1814-1852 , Xhosa (African people) -- History , Gcaleka (African people) -- History , Bantu-speaking peoples -- Migrations , Rharhabe (African people) -- History , Historiography -- South Africa , D'Urban, Benjamin, Sir, 1777-1849 , Land tenure -- South Africa -- Cape of Good Hope , Working class -- South Africa -- Cape of Good Hope , Eminent domain -- South Africa -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2572 , http://hdl.handle.net/10962/d1002425
- Description: The interpretations of the war of 1835 and the identity of the Fingo that were presented by the English settlers, have remained the mainstays of all subsequent histories. They asserted that the war of 1835 was the fault purely of 'Kaffir' aggression, that it was controlled by Hintza, the paramount chief, and that the ensuing hostilities were justifiable colonial defence and punishment of the Africans. The arrival of the Fingo in the Colony, it was claimed, was unconnected with the war. It was alleged that the seventeen thousand Fingo brought into the Colony in May 1835 were all Natal refugees who had fled south from the devastations of Shaka and the 'mfecane', and who had then become oppressed by their Gca1eka hosts. Both of these 'histories' need to be inverted. The 'irruption' of December 1834 was not unprovoked Rharhabe aggression, but the final response to years of the advance of the Cape Colony. Large areas of Rharhabe land had been expropriated, and their cattle regularly raided. Their women and children had been seized and taken into the Colony as labourers. The attacks were carried out by only a section of the Rharhabe on specific areas in Albany. The damage caused, and stock taken, was vastly exaggerated by the colonists. The Cape Governor, D'Urban, and British troop reinforcements arrived in Albany in January, and the Rharhabe were invaded two months later. D'Urban later invaded the innocent Gcaleka, took cattle, wreaked havoc and killed Hintza after he refused to ally with the Colony. The Fingo made their appearance at this moment. They were not a homogenous group. There were four categories within the term: mission and refugee collaborators (who were given land at Peddie and had chiefs appointed), military auxiliaries, labourers, and later, destitute Rharhabe seeking employment in the Colony. Only a small minority of the total Fingo were from Natal. The majority of the Fingo appear to have been Rharhabe and Gcaleka women and children, captured by the troops during the war and distributed on farms in the eastern districts to ameliorate the chronic labour shortage. Thus, instead of the year 1835 being one of great loss for the eastern Cape, as claimed by the settler apologists, it was a catalyst to the economic development of the area. All Rharhabe land was seized, to be granted as settler farms. Well over sixty thousand Rharhabe and Gcaleka cattle were captured and distributed amongst the colonists. The security threat of the adjacent Rharhabe and the independent Gcaleka was removed. And a large colonial labour supply was ensured.
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- Date Issued: 1991
The distribution patterns and community structure of the Tsitsikamma rocky littoral ichthyofauna
- Authors: Burger, Lynton Francois
- Date: 1991
- Subjects: Fishes -- South Africa -- Geographical distribution , Tripterygiidae -- South Africa -- Geographical distribution , Littoral plants -- South Africa -- Tsitsikamma , Littoral plants
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5260 , http://hdl.handle.net/10962/d1005104 , Fishes -- South Africa -- Geographical distribution , Tripterygiidae -- South Africa -- Geographical distribution , Littoral plants -- South Africa -- Tsitsikamma , Littoral plants
- Description: The results of a community survey of the rocky intertidal and subtidal reef ichthyofauna of the Tsitsikamma National Park and adjacent areas are presented. An updated species checklist is given, comprising 116 species of 46 families, including a new genus and species of Tripterygiid. Single species are shown to dominate, in terms of numbers, both the cryptic and subtidal components for all the areas sampled down the vertical profile. Species richness, evenness and diversity are found to increase with depth for both the cryptic and suprabenthic components. A community level feeding study shows an increase in trophic specialisation with depth and food availability is found to be an important factor delimiting littoral fish vertical distribution. The nursery function of the Tsitsikamma rocky littoral area is assessed and it is shown that shallow littoral areas as a whole are more important than intertidal pools alone in functioning as nurseries. The results of the study are found to fit into the existing trend of an increase in species richness and diversity, from west to east, along the South African coast. A significant difference is shown between the observed frequencies of species on exploited reefs outside the Park and unexploited reefs inside the Park. The density of the key reef predator Petrus rupestris is shown to be nine times more abundant on deep reef inside the park compared to deep reef outside the park (0.0045 fish/m² and 0.0005 fish/m² respectively) and a paucity of larger individuals of this species on exploited reefs is noted. Marked differences in the relative abundance of other species between exploited and unexploited reefs are evident and it is hypothesised that community disruption has occurred on exploited reefs, either directly or indirectly because of the removal of P. rupestris. These results are discussed in the context of marine reserves as a conservation strategy and a recommendation is made to extend the 5.6km seaward boundary of the Tsitsikamma National Park westwards to include the large concentration of presently exploited rocky reefs between the Blaaukrans river mouth and Natures Valley.
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- Date Issued: 1991
The informal sector in the Eastern Cape: a case study of New Brighton and Kwamagxaki, Port Elizabeth
- Authors: Sofisa, Thembela Nicholas
- Date: 1991
- Subjects: Informal sector (Economics) -- South Africa -- Port Elizabeth , Self-employed -- South Africa , New Brighton (Port Elizabeth, South Africa) , Port Elizabeth (South Africa) -- Economic conditions , KwaMagxaki (Port Elizabeth, South Africa)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:934 , http://hdl.handle.net/10962/d1002667 , Informal sector (Economics) -- South Africa -- Port Elizabeth , Self-employed -- South Africa , New Brighton (Port Elizabeth, South Africa) , Port Elizabeth (South Africa) -- Economic conditions
- Description: Recently, researchers have shown enormous interest in the informal sector due to extensive poverty and rising unemployment trend in the South African economy. These problems have worsened in the Port Elizabeth economy, as most entrepreneurs have scaled down their operations or liquidated their businesses due to a structural decline in the manufacturing sector and periodic recessions in the national economy. Undoubtedly, the informal sector has become a reasonable economic alternative as far as income accumulation and employment generation. The present study shows that the informal sector is characterised mainly by self-employment and also the income from this sector has also improved the standard of living of most sampled households in New Brighton and KwaMagxaki. The aim of this thesis, then, is to evaluate the nature, extent, meaning and influence of the informal sector in the Port Elizabeth Black economy. However, this can only be achieved once the informal sector is placed within the appropriate theoretical framework. This is done by comparing and contrasting the different conceptualisations of the informal sector in the literature. In conclusion, the thesis combines the different conceptualisations of the informal sector in the literature with the empirical evidence from the Port Elizabeth townships' informal sector. The important findings of the study are: The informal sector is mainly characterised by distributive activities than productive activities. Women comprised 62% of the informal sector. Economically-active members of the economy are in the informal sector. Education levels in this sector are relatively low. The informal sector is characterised by one-man businesses with few employees who are also family members. There was no trace of migrants in the informal sector. The informal sector is characterised by linkages. Informal income alleviates conditions of poverty. Policies have to implemented for the development of the informal sector. Twenty-three percent of the households in New Brighton were in the informal sector and only 6% in KwaMagxaki. Although, this study focuses in Port Elizabeth, it is the intention that the results presented will provide a broad overview of what the informal sector is.
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- Date Issued: 1991
A pilot study of the relationship between the English language abilities of a group of primary school children and their tree-drawings
- Authors: Kierman, Wynsome Doreen
- Date: 1991
- Subjects: Children -- Language -- Research Children -- Language -- Study and teaching -- Research Cognition in children Communicative competence in children -- Research English language -- Study and teaching (Primary) -- Research
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1704 , http://hdl.handle.net/10962/d1003587
- Description: This pilot study attempts to assess the correlation between language ability and a projective Tree-drawing test. The hypothesis tested is that expounded by Sandra Michel, a psychologist working with Dr. A. A. Tomatis at the Language Centre in Paris. The theory of Language from which her work derives is that put forward by A. A. Tomatis in Vers l'écoute humaine (Towards Human Hearing), (1977) and Education and Dyslexia trans . , Louise Guiney, (1972). This hypothesis states that the Tree-drawing can give a clear indication of the kind of dialogue the testee will be able and willing to use. The claims for projective Tree-drawing 'tests' or techniques have been mainly concerned with personality or psychological assessments and sometimes with intelligence testing since Charles Koch first began his work in this field in the early forties. Sandra Michel in "The Tree Test", translated by T . Brown, (unpublished paper), Tomatis Centre (Scarbrough, Ontario, 1980) discusses a Tree-drawing scale that indicates both the developmental level of the child's language ability and his/her motivation towards dialogue and communication at this level. To test this hypothesis a sample of 1094 Tree-drawings was used. The drawings were done by Primary School children of both sexes from Sub. A. to Std . 5, collected over four years of research. These drawings were studied to see if the Tree scale of drawings described by Michel did in fact occur and if they occurred in the sequence she suggests. As a result of these preliminary investigations a developmental scale was devised and proposed as a refinement of Michel's scale. Scores from these two Tree-scales were correlated with English language scores using Pearson Product Moment Correlation Coefficient and the Spearman Rank techniques. The sample for this correlation study was a group of 54 Std. 5 pupils whose English language ability was evaluated by (i) a school English Examination mark, (ii) a Questionnaire scoring receptive and expressive language behaviours and (iii) Verbal I.Q. scores. The positive correlation between these language scores and the Tree-drawing projective test scores are discussed and the implications for English language teaching and suggestions for further research mentioned.
- Full Text:
- Date Issued: 1991
Environmental and socio-economic effects associated with the planting of Atriplex nummularia Lindl. (Oldman saltbush) in the Karoo
- Authors: Hobson, Colin Desmond
- Date: 1991
- Subjects: Botany, Economic Plant introduction -- South Africa -- Karoo Plants, Cultivated
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: vital:4794 , http://hdl.handle.net/10962/d1001894
- Description: This study examines the environmental and socio-economic effects associated with the planting of Atriplex nummularia Lindl. (Oldman saltbush) in the karoo. This is the first study of its kind on oldman saltbush and serves as an important scoping exercise in assessing the impact of saltbush on its surrounds and in identifying additional aspects which require investigation. The environmental parameters investigated include microclimatic effects, soil induced changes, salinity effects on the germination of selected karoo species and compositional changes in the indigenous plant community within a saltbush plantation. When compared to indigenous karoo plant species oldman saltbush is found to ameliorate soil temperatures and increase surface soil salinity (specifically sodium chloride), on an individual plant basis. Salinity is shown to have a differential effect on the germination of selected karoo shrubs. The indigenous plant community within a forty year old saltbush plantation is impoverished with both density of individuals and species richness being markedly reduced. Saltbush is identified as an unsuitable nurse plant for the majority of karoo shrubs. Farm size in relation to both actual and intended area established to saltbush is considered. The area of saltbush already established in the karoo is considered too insignificant to have any wide socio-economic impact. Farmers who intend planting large areas of their farms to saltbush are in the minority. It is those farmers who already have some saltbush planted, who intend planting more. Ecologically based management guidelines are presented, suggesting practices which minimize the detrimental effects of saltbush on soil salinity and the indigenous plant community. These guidelines are practical and in keeping with the overall objectives of optimum resource utilisation and the national grazing strategy for South Africa.
- Full Text:
- Date Issued: 1991
An investigation into the relationship between kinesthetic sensitivity and balancing ability in pre-school children
- Authors: Burger, Laetitia Mary
- Date: 1991
- Subjects: Motor ability in children Perception in children Preschool children
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1615 , http://hdl.handle.net/10962/d1003497
- Description: The purpose of this study was to explore the possibility of a linear relationship between kinesthetic sensitivity and balancing ability in pre-school children. Furthermore, the effects of age on kinesthetic sensitivity and balancing ability were investigated. Finally, the role of gender in kinesthetic sensitivity and balancing ability was examined. Fifty-one subjects, between the ages of three and six years, executed five trials on each of two kinesthetic sensitivity tests (an arm abduction test and a hip abduction test); two tests for static balance (on a balance board and on a balance stick) and two tests for dynamic balance (a beam walk test and a stepping stones test). Although the correlations between kinesthetic sensitivity and balancing ability were generally positive, they were very slight. These low correlations are probably an indication that different abilities are required for carrying out the different tasks. Generally, both balancing ability and kinesthetic sensitivity appeared to improve with age. From analysis of individual test results it was obvious that abilities varied from individual to individual (Appendix G). This could have been the result of developmental, motivational or experiential differences. Although the girls generally performed slightly better on most tests than the boys the correlations between test scores for boys were slightly higher than those for girls. At-test indicated that there were no significant differences between the mean scores of the boys and the girls on the balancing or the kinesthetic sensitivity tasks.
- Full Text:
- Date Issued: 1991
Mantle xenoliths from the Abrahamskraal kimberlite : a craton-margin geotherm
- Authors: Nowicki, Thomas Edward
- Date: 1991
- Subjects: Kimberlite , Kimberlite -- Inclusions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4898 , http://hdl.handle.net/10962/d1001557
- Description: The Abrahamskraal kimberlite pipe (group I) occurs approximately 5 km to the south-west of the geophysically defined margin of the Kaapvaal craton in the central Cape Province, and contains a variety of crustal and mantle xenoliths. This study focusses on xenoliths of deep-seated origin (mantle and lower-crustal), and in particular on garnet-orthopyroxene bearing assemblages which are amenable to thermobarometric techniques. Four major types of deep-seated xenolith have been identified, i.e. peridotites, dunites , eclogites, and garnet pyroxenites. The petrographic features and mineral compositions of these xenoliths are described . Pressures and temperatures of equilibration have been calculated primarily using the garnet-orthopyroxene thermometer of Harley (1984), and the Al-in-enstatite barometer of Nickel and Green (1985). The peridotites are coarse-textured (Harte, 1977), magnesium -rich rocks, and are typical examples of the common type I peridotites which generally dominate mantle xenolith suites in kimberlites. Garnet peridotite xenoliths define a geotherm which lies along a typical theoretical conductive geothermal gradient for shield areas (Pollack and Chapman, 1977), and which extends to a maximum pressure of 41 kb (~130 km). Comparison of the Abrahamskraal geotherm with that constructed for the northern Lesotho xenolith suite (calculated using the same thermobarometer couple), suggests that the lithosphere at the Namaqua /Kaapvaal boundary is not significantly thinner or hotter than that underlying the craton. Modelling of the craton boundary under the constraints provided by the Abrahamskraal geotherm, and by the distribution of diamond-bearing kimberlites in southern Africa, indicates that the Abrahamskraal kimberlite has sampled relatively thick, cool , Namaqua lithosphere. It is suggested that, in terms of diamond distribution, the age and magmatic history of the Namaqua lithosphere is of greater significance than its thickness. Two varieties of dunite occur at Abrahamskraal. Coarse-textured dunites with Mg-rich olivine compositions similar to those of the peridotitic olivines, probably originated by similar (but perhaps more extreme) processes to those which formed the peridotites. A finer-grained and relatively Fe-rich variety of dunite may represent ultramafic cumulates formed by fractionation of basic or ultrabasic magmas within the mantle. Two varieties of eclogite have been distinguished. Coarse-grained eclogites which yield relatively high temperature estimates, are believed to have originated from depths similar to those determined for the garnet peridotites, i.e. from the lower lithosphere. A distinctly finer grained variety of eclogite, yields significantly lower temperatures which may be based on frozen-in equilibria. A maximum depth of approximately 87 km (~ 27 kb) has been estimated for these xenoliths, but they may have originated from significantly shallower (possibly lower-crustal) levels. The garnet pyroxenite xenoliths are generally orthopyroxene-rich rocks which contain varying amounts of garnet (8 to 33 %) and clinopyroxene (0 to 64 %). Textural features indicate that the garnet and possibly some of the clinopyroxene has exsolved from an originally A l -rich orthopyroxene. The rocks are significantly more Fe-rich than the peridotite xenoliths, and their constituent minerals show a wide range of Mg/Mg+Fe ratios. The pressure-temperature array defined by the garnet pyroxenites is approximately isothermal, and spans a depth range from approximately 30 to 95 km. It deviates strongly (to higher temperatures) from the ambient geothermal gradient at the time of kimberlite emplacement, as inferred from the garnet peridotite xenoliths. The pressures and temperatures calculated for the garnet pyroxenites are based on mineral equilibria which are believed to have been frozen-in during cooling from an intial hightemperature (probably molten) state. Qualitative modelling of possible cooling paths in pressure-temperature-composition space, indicates that the apparent depth range displayed by the garnet pyroxenites, approximates the true depth range over which these rocks were emplaced. However, the apparent pressures calculated from core compositions are significantly lower than the true pressures at which the original rocks formed . The garnet pyroxenite xenoliths appear to represent a major, possibly Namaqua age (~1000-1400 Ma), magmatic event involving the emplacement of large amounts of mafic magma over a significant depth range in the shallow upper mantle
- Full Text:
- Date Issued: 1991
South African anti-apartheid documentaries 1977-1987: some theoretical excursions
- Authors: Steenveld, Lynette Noreen
- Date: 1991
- Subjects: Documentary films -- South Africa -- History and criticism , Apartheid -- South Africa , Anti-apartheid movements -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3484 , http://hdl.handle.net/10962/d1002939 , Documentary films -- South Africa -- History and criticism , Apartheid -- South Africa , Anti-apartheid movements -- South Africa
- Description: This study examines anti-apartheid documentary production in South Africa between 1977 and 1987. These documentaries were produced by a variety of producers in order to record aspects of South Africa's contemporary social history, and as a means of contributing - in some way - to changing the conditions described. While the 'content' of the documentaries is historical and social, and their intention political, this study is aimed at elucidating how a documentary, as a representational system, produces meaning. The study is therefore located within the discourse of film studies. My study is based on the theory that a documentary is the embodiment of several relationships: the relationship between social reality and documentary producers; the social relationships engaged in, in the production of the text; the relationship between the text and its audience 1, and the relationship between the audience and its social context. This informs my methodological approach in which analysis appropriate to each area of study is used. Using secondary sources obtained through standard library research, I pursue social and historical analysis of the 1970s and 1980s in order to contextualise both the producers of the documentaries, and their audience. The social relations of production of a text are examined using material gathered through extensive interviews with the producers and published secondary material. How this impinges on the documentary is ascertained through detailed textual analysis of 30 documentaries. For analytical clarity each chapter focuses on a specific aspect of documentary - although I do show how the various relationships impinge on each other. This research finds that the documentaries faithfully reflect the anti-apartheid ideology dominant in the extra-parliamentary opposition in the period under discussion - to the extent that all forms of consciousness are framed by this discourse. An examination of the textual strategies used shows that they are bound by the conventions of broadcast television. They therefore construct a spectator-text relationship which is not consistent with the political concern that democratic relationships be established as the basis of a post-apartheid society. In other words, there is an inconsistency between the ideology espoused, and the way in which film- and videomakers, in their specialised field of production, practise their politics. This can be attributed to the over-riding political intention of the documentarists 'to record' what is happening, and to establish a popular archive which can be used by extra-parliamentary opposition groups in their struggle against apartheid.
- Full Text:
- Date Issued: 1991
The digestive mechanisms of an intertidal grazer, the sea urchin Parechinus angulosus
- Authors: Sweijd, Neville Anthony
- Date: 1991
- Subjects: Sea urchins -- Nutrition , Sea urchins , Echinoida
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5662 , http://hdl.handle.net/10962/d1005346 , Sea urchins -- Nutrition , Sea urchins , Echinoida
- Description: Echinoids are important grazers in the near-shore ecosystem and can significantly effect their ecology. The sea urchin Parechinus angulosus occurs inter- and subtidally along the southern African coast. Within this range it consumes an extremely wide variety of algae. Since algal cell walls have an almost species specific chemical composition, the question arises as to how it can digest the algae that it consumes. In order to investigate the digestive mechanisms employed by P. angulosus, an ultrastructural study of the gut was undertaken to characterize the tissue and identify functional regions in the gut. Ten structural and storage polysaccharides commonly found in macroalgae were used as substrates to assay the digestive polysaccharidases of the sea urchin. The enteric bacteria of the sea urchin were isolated and tested separately for polysaccharidase activity using the same substrates. The results shown that the gut of Parechinus angulosus is regionally specialized, with the foregut primarily responsible for the production of hydrolytic enzymes, while the hindgut is primarily absorptive. The occurrence of lamellar bodies, heterolysosomes, cytoplasmic blebs and paddle cilia among other characteristic features of the digestive epithelium are described and discussed. Two levels of enzyme activity are apparent. Generally the urchin could hydrolyze the reserve polysaccharides, but only partially hydrolyze the structural polysaccharides, of red and green algae. P.angulosus was unable to digest alginic acid, the main structural polysaccharide of brown algae. Mixed cultures of bacteria utilized only the reserve polysaccharides of red and green algae. Significantly, the bacteria were able to hydrolyze alginic acid. Enteric bacteria also showed agarolytic activity. Parechinus angulosus has the ability to digest red and green algae. No lysozyme activity was detected. The enteric bacteria can digest the same algal reserve polysaccharides and so may compete for carbon in the gut. However, in the case of brown algae, bacteria have a potentially important endosymbiotic role as agents of digestion. These results correspond with food preference studies which have shown that, although P.angulosus consumes the kelp Ecklonia maxima, in the western Cape, it is amongst its least preferred food species. The reasons for this are its unpalatability and the urchin's inability to digest brown algae. The digestibility of algal material can be an important factor in determining algal-herbivore interactions.
- Full Text:
- Date Issued: 1991
Chemical studies of 1,5-benzodioxepanones
- Authors: Gelebe, Aifheli Carlson
- Date: 1991
- Subjects: Biochemistry , Pigments (Biology) , Benzopyrans
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4423 , http://hdl.handle.net/10962/d1006895 , Biochemistry , Pigments (Biology) , Benzopyrans
- Description: Chromone and flavanone derivatives were prepared by condensation of the corresponding 2-hydroxyacetophenones (with diethyl oxalate or the appropriate aromatic aldehyde respectively) and cyclisation of the condensation products. Saeyer-Villiger rearrangement of these flavanones, with MCPBA, resulted in expansion of the C-ring. Spectroscopic techniques have been used to establish the regioselectivity of the rearrangement and hence, the identity of the rearranged products as 1,5-benzodioxepan-4-ones. The 1,5-benzodioxepan-4-ones were subjected to detailed ¹H and ¹³C n.m.r. analysis and a combination of low and high resolution mass spectrometry has been used to study the mass fragmentation pathways of these ring-expanded products.
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- Date Issued: 1991
A critical review of contemporary dance/movement therapy
- Authors: Du Plessis, Nicolette
- Date: 1991
- Subjects: Dance therapy , Modern dance
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2135 , http://hdl.handle.net/10962/d1002367 , Dance therapy , Modern dance
- Description: This critical review aims to describe and define the field of dance/movement therapy. Attention is paid to central issues in psychology and dance studies which influence the advancement of the modality. Dance/movement therapy is a young profession, developed during the second half of this century, and must be viewed within the socio-cultural context of contemporary western industrialized societies. This work therefore firstly documents the development of dance/movement therapy in the light of recent studies into the nature of bodily expression and non-verbal communication. The phenomenological understanding of the human body is discussed, and the concept of bodyliness proposed in order to encapsulate a multi-dimensional understanding of the meanings of the human body. Dance/movement therapy is then delineated in relation to verbal psychotherapeutic traditions, as well as to the more marginalized body therapies. In this way it is hoped to provide an understanding of the historical precedents and theoretical contexts within which dance/movement therapy is emerging, and ultimately the possibly unique alternative service it may provide. As wide a variety as possible of theoretical approaches in dance/movement therapy is then described, and classified according to the predominant psychological orientation of the proponents. From this a critical review is attempted which is directed broadly at foundational considerations of the profession, rather than at any particular methodology. The enquiry focusses on directions for future possible research which will ensure sound theoretical frames of reference for the developing profession. Discussion of two examples of dance being used in the therapeutic context in South Africa concludes. This section is not a judgmental evaluation of techniques, but intended rather as documentation and broad classification of current work of this nature.
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- Date Issued: 1991