Chemical and spectroscopic studies of chromone derivatives
- Authors: Davidson, Deborah Nicole
- Date: 1992
- Subjects: Chromatophores Plant pigments Asthma -- Treatment -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4420 , http://hdl.handle.net/10962/d1006857
- Description: Various chromone derivatives have been used in asthma therapy, and their biological activity is apparently related to certain chemical features which include conformation and acidity. In the present study, substituent effects on conformation and acidity have been explored in chromone systems with potential biological activity. A range of variously substituted symmetrical chromone-2-carboxamides (including a series of N,N-dimethylchromone-2-carboxamides) have been prepared via chromone-2-carboxylic acids, which, in turn, were prepared from the corresponding o-hydroxyacetophenones. The N,N-dimethylchromone-2-carboxamides were prepared by reacting the appropriate chromone-2-carbonyl chlorides with dimethylammonium chloride in pyridine, in an approach which resolved various problems encountered in the preparation of these compounds. Substituent effects on the conformation of chromone-2-carboxamides have been explored using dynamic NMR spectroscopy, and the observed splitting of the N-alkyl signals has been attributed to slow site-exchange of the N-alkyl substituents. Dynamic NMR frequency separations and coalescence temperatures have been used to calculate rotational energy barriers, and substituent effects on these rotational energy barriers have been analysed. The possible implication of ring-opening of chromones in chromone pharmacology has also been examined. A range of 3-(2-hydroxybenzoyl)acrylamides has been prepared via the dimethylamine-mediated ring-opening of N,N-dimethylchromone-2-carboxamides and the E-double-bond configuration of the ring-opened products has been unambiguously established by single crystal analysis of the parent system. The configuration and conformation of the crystal structure of the parent system have been shown, using IR and NMR spectroscopic, and molecular graphics techniques, to be maintained in solution and to characterise the whole series. ¹H and ¹³C NMR spectroscopy have also been used to study the dimethylamine-mediated ring-opening of disodium cromoglycate. The kinetics of the dimethylamine-mediated ring-opening of N,N-dimethylchromone-2-carboxamides have been studied using UV spectroscopy. These reactions have been shown to follow third-order kinetics overall and a mechanism accommodating the observed third-order kinetics has been proposed. Substituent effects have been further investigated by the potentiometric determination of the pKa (pK [subscript a]) values for a series of chromone-2-carboxylic acids. The relationship between acidity and the observed rate constants has been explored and has verified that the observed rate constants are sensitive to the influence of meta-substituents on the stability of the phenoxide ion "leaving group" rather than C-2 electrophilicity.
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- Date Issued: 1992
Chibhudhu
- Authors: Venancio Mbande and his Chopi timbila xylophone group , Tracey, Andrew T N
- Date: 1992
- Subjects: Chopi (African people) -- South Africa , Folk music , Xylophone music , Rattle (Musical instrument) , Drum (Musical instrument) , Africa South Africa Rustenburg f-sa
- Language: Chopi
- Type: sound recordings , field recordings , Sound recording material
- Identifier: http://hdl.handle.net/10962/96471 , vital:31283 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC049b-02
- Description: Traditional dance song accompanied by timbila xylophone rattles and one drum
- Full Text: false
- Date Issued: 1992
Complete regularity and related concepts in L-uniform spaces
- Authors: Harnett, Rait Sicklen
- Date: 1992
- Subjects: Uniform spaces , Mathematics -- Research
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5403 , http://hdl.handle.net/10962/d1005217 , Uniform spaces , Mathematics -- Research
- Description: L will denote a completely distributive lattice with an order reversing involution. The concept of an L-uniform space is introduced. An extension theorem concerning L-uniformly continuous functions is proved. A characterisation of L-uniformizability, involving L-complete regularity is given. With respect to L--completely regular spaces it is shown that the topological modification of an L-completely regular space is completely regular. Furthermore it is shown that the topologically generated L-topology of a completely regular space is L-completely regular.
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- Date Issued: 1992
Dance and sexual politics some implications of the status of women in selected dance forms
- Authors: Poona, Sobhna Keshavelal
- Date: 1992
- Subjects: Dance -- Social aspects , Sex discrimination against women
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2145 , http://hdl.handle.net/10962/d1002377 , Dance -- Social aspects , Sex discrimination against women
- Description: This thesis explores, from a feminist perspective, some implications on the status of women in selected dance forms, and addresses the perceptions of women as 'inferior' and 'subordinate'. One of the intentions behind the work was, indeed, to challenge prevailing perceptions and create an awareness of sexism, capitalism and patriarchy, especially for the uncritical and uninformed who have become its victims. Part 1 offers an analysis of the premises upon which social, political and economic inequality are founded and consolidated, with specific reference to sexual inequality and sexual prejudice. Utilising a Marxist-feminist and semiotic approach, the machinations of the traditional mass media are linked to negative imaging of the female body in support of the sexist, patriarchal, capitalist male manipulator, who benefits from women's subordinate social status. Part 2 addresses the issue of sexual politics, and the implications for dance research and performance. The researcher offers a descriptive analysis of four specific dance forms, which serve to highlight the socialisation and educational processes that shape our perceptions and instruct our lives. A set of questionnaires was sent to fourteen autonomous dance institutions, including those attached to national performing arts councils. The thesis concludes with a summary of the results of the questionnaires that were distributed amongst female dancers, dance students and choreographers. The researcher questions our culture's preoccupation with the female body image, and posits the urgent need for an assessment of this situation, and an education which will create a better understanding and a more harmonious climate for development.
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- Date Issued: 1992
Developing a problem solving approach to primary mathematics teaching: a case study
- Authors: Naidoo, Anandhavelli
- Date: 1992
- Subjects: Mathematics -- Study and teaching (Elementary) Problem solving -- Study and teaching (Elementary)
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1493 , http://hdl.handle.net/10962/d1003374
- Description: According to recent research a focus in teaching mathematics to children is the development of problem solving abilities. Problem solving means the process of applying mathematical knowledge and skills to unfamiliar situations. A case study was done using a problem solving approach to the learning and teaching of mathematics with a sample of teachers registered at the Umlazi College For Further Education. These teachers were familiar with the traditional approach of teaching mathematics through drill and practice methods. The new syllabus that is to be implemented emphasises a problem solving approach to the teaching of mathematics. This study set out to implement a problem solving approach with primary school mathematics teachers so that they would be someway prepared for the innovations of the new syllabus. Workshops were conducted using an action research approach with discourse and practice leading to reconstruction with improvements. Early theorists like Piaget and Bruner offered ways of understanding children's learning, to help the teacher develop his teaching. Dienes introduced an element of play and Dewey spoke of the importance of experience. Dienes and Dewey show the first positive signs of recognising the importance of social interaction in the learning situation. Social interaction lays emphasis on language and discussion in the mathematics classroom. A social constructivist model of teaching and learning was used for the research. This research includes a study of the established ideas on developing a problem solving approach to mathematics teaching. These ideas were incorporated into the workshops that the group of teachers attended. During the workshops teachers were gradually exposed to the essence of problem solving techniques through much group discussion and doing practical exercises, which they could then implement in their classes. The teachers reported back at each subsequent workshop. A non-participant observer evaluated the development at the workshops. The workshops' success was evident from the change in the teachers' attitudes and behaviour as well as their feedback of what transpired in the classroom. They reported on the change in their roles as information suppliers to facilitators where the thinking process was focused on, rather than the importance of a correct answer. In the workshops the teachers themselves moved from passive listeners to active participants. It would appear from this preliminary investigation that through using a problem solving approach in workshops, inservice teachers can benefit constructively from this approach and will attempt to use it in their own teaching.
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- Date Issued: 1992
Die sosio-ekonomiese opname as instrument vir die inisiëring van 'n ontwikkelingsproses in 'n landelike gemeenskap met spesifieke verwysing na Wartburg
- Authors: Rossouw, Anthonie Michael Müller
- Date: 1992
- Subjects: Community development -- South Africa -- Wartburg Social service -- South Africa -- Wartburg Social service -- Research Rural poor -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3280 , http://hdl.handle.net/10962/d1006475
- Description: Aim of this study. The problem of poverty, especially in rural S.A ., formed the basis for the questions and hypotheses posed in this study. Poverty stricken communities, with the accompanying suffering, the immobilizing effect of poverty and the present climate of urgent changes in S.A., were also apparent in Wartburg (study area). The problem was to initiate development in such a way that the chances of failure and therefore the wasting of already scarce resources is minimized. The manner in which development is initiated and what are viewed as desirable elements of development should culminate into achieving self-sustaining development in the long term. It became clear therefore that a complete data base needs to be established in order to initiate such a development process. In this study the aim was to investigate the role which research plays in the process of development. Method. This study can be divided into two sections, viz an investigation into the theoretical basis for achieving a self-sustaining process of development and how research should be done within such a process. Secondly, the practical application of such a theoretical basis was tested and forms the empirical section of this study. The first section was completed by undertaking a literature study. The conditions set for the development process guided the researcher increasingly to a holistic perspective, Community Development and the state of the art of Social Work Practice. The second part of this study was done through empirical research. The questionnaire method was utilized where structured interviews were conducted by properly trained field workers who were of similar cultural background as the community involved in the survey. The data was processed by using the B.M.D.P. programme and recorded in section B of this report. From section A and B of this report conclusions were drawn regarding the development process, the role research has in this process and the task of the Social Work Profession in this regard. Findings. From the theory it seemed that the state of the art regarding social Work Practice upholds a holistic perspective and views community practice and development as an important function within this perspective. It seems that a unitary approach to Social Work is increasingly becoming a reality in the pursuit of a holistic perspective as well as by stressing the importance of community practice. The integrated approach to Social Work Practice seems to collaborate with these views. The role of research is equally important to social Work Practice as it is to Community Development and should be viewed as an integral part of the Social Work Process/Practice. The empirical section of this study is a clear example of what can be achieved by a properly planned and executed research project which forms an integral part of a development process. Together with the community valuable data were drawn from the data base. These conclusions were directly employed to identify priorities and in planning specific projects. Conclusions. This study concludes, firstly, that Social Work Practice has an obvious task in the field of community development. This profession can contribute to a large extent toward making development more human and to acknowledge the importance of both man and his environment when considering development. The study also showed that research is an integral part of a development process, especially where the aim is that of a perpetuating, self-sustaining development process. In short, it seems that the Socio-economic research meets the requirements set by the aforementioned development process, but that refining seems necessary in order to make it more effective and useful as an instrument for initiating such a process of development as discussed in the above paragraphs.
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- Date Issued: 1992
Domestic strategies of rural Transkeian women
- Authors: Cloete, Laura
- Date: 1992
- Subjects: Rural families -- South Africa -- Transkei Women -- South Africa -- Transkei Women -- South Africa Sex role -- South Africa -- Transkei Rural women -- South Africa -- Transkei Transkei (South Africa) -- Social conditions Transkei (South Africa) -- Rural conditions Transkei (South Africa) -- Economic conditions
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/2014 , vital:20247 , ISBN 0868102342
- Description: This research, originally undertaken as part of a B.A.(Honours) Degree in Anthropology, has several aims. Firstly, it aims to reveal the various community options available to women in rural Transkei for coping with their domestic activities in the face of the large-scale absence of men. It will analyse the rationale behind the choices and their consequences for the women’s workload. Secondly, this will illuminate gender and generational roles and attitudes of community members, present and absent, in the community. The focus, in this case, will be predominantly on women, however. Thirdly, and finally, this research will analyse the relationships of power between men and women, and between adults and children by examining the various influences, such as religion and education, which constrain and coerce their behaviour and attitudes. From this, we should be left with an illuminating picture of the forces under which women operate in rural Transkei; and with some insight into their behaviour and attitudes, their beliefs and aspirations and into their lives. , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
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- Date Issued: 1992
Ecological effects of impoundments in the Buffalo River, Eastern Cape, with particular reference to the distribution of blackflies (Diptera : simuliidae)
- Authors: Palmer, Robert William
- Date: 1992
- Subjects: Stream ecology -- South Africa -- Buffalo River (Eastern Cape) Dipter -- South Africa -- Buffalo River (Eastern Cape)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6028 , http://hdl.handle.net/10962/d1006157
- Description: This thesis examines the extent and intensity of the effects of impoundments on selected physical, chemical and biotic conditions in an impounded southern African river. Life-history characteristics and environmental requirements which determine the success of impoundment-outlet blackflies in southern Africa were studied. Difficulties with the identification of immature blackflies led to a search for additional diagnostic characters, the description of larvae of seven species previously unknown, and the development of new keys to the species of Simulium (larvae and pupae) in southern Africa. Distribution records for each species are presented, and their ecology is summarised. Three pairs of closely related species, which were formerly indistinguishable, can now be recognised by differences between the structure of their cephalic fan microtrichia. Monthly physical, chemical and invertebrate samples at 16 sites upstream and downstream of four impoundments in the Buffalo River, eastern Cape, were taken over a period of two years. The downstream effects of impoundments on these parameters depended on the variable examined, the position of the impoundment along the river profile, the depth from which water was released, and the quality of the inflowing water. Impoundments in the Buffalo River caused an upstream shift of the thermal and suspended organic conditions, and the distribution of blackfly species. Surface-release impoundments in the clean, upper-reaches of the river caused increases in water temperature (by as much as 8ºC) and chlorophyll a (by as much as 600%). Recovery to riverine conditions was within 2.6 to 18.4 km, depending on flow. A polluted, surface-release impoundment in the middle-reaches of the river had a slight dampening effect on river temperatures, converted the particle size spectrum of the river from small (<80 μm) to large (250-1000 μm), and improved the water quality of the downstream reaches (with the exception of nitrate concentrations, which were higher in the tailwaters compared to inflowing water). An impoundment in the lower reaches caused reductions in maximum temperature of up to 6ºC when releasing water from the surface, and up to 16ºC when releasing water from the bottom. Bottom-released water carried high concentrations (36 to 190 g m³) of small (<5 μm) and largely inorganic (86 to 93%) material.Twenty species of blackflies were found in the Buffalo River, of which 18 were distinguishable as larvae. They were divided into those which were widespread (5 taxa), those restricted to waterfalls and mountain torrents (2 taxa), those found in the foothill stony run zone (6 taxa), and rare taxa (5 taxa). Impoundments in the Buffalo River did not alter population densities of blackfly larvae, but did alter blackfly species composition, favouring five species commonly found in mid-order streams in southern Africa (s. meduseaforme, S. hargreavesi, S. nigritarse, S. adersi and s. damnosum s.l.) at the expense of upper-reach species (s. rutherfoordi, S. letabum and s. impukane). These five species are regarded as typical of impoundment-outlets, and were small, multivoltine flies whose larvae shared a generalised cephalic fan microtrichial structure, consisting of a single row of moderately differentiated microtrichia. A strong relation was found between cephalic fan microtrichial structure and larval habitats: Taxa found in fast-flowing, clear water had a more complex fan structure compared to those found in slow-flowing, turbid water. It is concluded that impoundment-induced changes to hydrodynamics and transported material (food) are important factors which have changed the distribution of blackflies in southern Africa in recent times. These changes are more severe downstream of upper-reach impoundments than middle or lower-reach impoundments.
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- Date Issued: 1992
Educational computing in secondary schools of the Cape Education Department: a research survey to assess computing facility acquisition and its utilization
- Authors: Bean, Pat
- Date: 1992
- Subjects: Education, Secondary -- South Africa -- Data processing Education, Secondary -- South Africa -- Computer network resources Computer-assisted instruction -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1505 , http://hdl.handle.net/10962/d1003387
- Description: Secondary schools under the jurisdiction of the Cape Education Department (CED) have, over the past 10 years, been acquiring computer equipment without a national policy on educational computing in South Africa, and within only broad parameters provided by their department. The aim of this study was to determine the present status of educational computing in these schools. A literature survey on educational computing was undertaken and a number of international and local 'computers-in-schools' initiatives were elucidated. A field survey, involving all CED secondary schools (239), was initiated by sending questionnaires to principals of these schools - a return rate of 89% was achieved. The results of the research revealed that most CED secondary schools have already acquired computer facilities. The role of pressure groups such as teachers, parents, business sector etc together with other factors that might have influenced schools in acquiring their computer facilities was also investigated. The investigation also revealed where and how these facilities are being utilised: most schools use their computers for administrative functions, with the computer-as-a-tool for teachers and pupils also fast gaining ground. Computer-assisted learning activities, where the computer is integrated with subject curricula, are however still limited. The extent of both teachers' formal training in educational computing and their familiarity with different software applications were also determined. Schools were also required to indicate the areas where they experience problems in getting teachers and pupils more involved in 'computers-in-education' activities. The present educational computing position in secondary schools of the CED will have to serve as a foundation for the department's CISR Project embarked upon in 1991.
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- Date Issued: 1992
Educational needs of adults in Mdantsane
- Authors: McAllister, Patrick A , Young, Michael , Manona, Cecil W , Hart, Jo
- Date: 1992
- Subjects: Adult education -- South Africa -- Mdantsane (Ciskei) Adult education -- South Africa -- Mdantsane (Ciskei) -- Case studies
- Language: English
- Type: Book , Text
- Identifier: http://hdl.handle.net/10962/2079 , vital:20253 , ISBN 0868102423
- Description: The purpose of the study was to collect some preliminary information in advance of the inauguration of a new educational project at Fort Hare University which, under the guidance of a new Vice-Chancellor, Dr. S.M.E. Bengu, is forging for itself a new course of development as a people's University. The new project arises out of a report prepared by the International Extension College for the University of Fort Hare. The hope is that a number of innovations can be introduced into adult education in the Eastern Cape which will prove of value in meeting the needs of people living in different kinds of localities. The planning will begin in the early winter, as soon as staff have assembled, and as soon as Dr. David Warr, the international consultant to the project, is in post. It seemed sensible to conduct, in advance, one of the surveys which will be needed to underpin plans. To do this at short notice and complete it in a short time (the work did not commence until February, 1992) the best course was to rely on an experienced team from a neighbouring University, Rhodes, which had already conducted surveys in different districts within the Eastern Cape, and to bring in further support from the University of Natal , Digitised by Rhodes University Library on behalf of the Institute of Social and Economic Research (ISER)
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- Date Issued: 1992
Environmental education in primary schools in Bophuthatswana : a case study in curriculum implementation
- Authors: Shongwe, Doctor Petrus
- Date: 1992
- Subjects: Environmental education -- South Africa -- Bophuthatswana , Primary school teaching -- Research -- South Africa -- Bophuthatswana
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1514 , http://hdl.handle.net/10962/d1003396
- Description: This study examines the extent to which teachers in Senior Primary Schools who have obtained a professional qualification in Environmental Education, implement Environmental Education in their schools. It also explores factors which influence the implementation of Environmental Education at the Senior Primary School. Teachers who had qualified from Tlhabane and Hebron Colleges of Education were interviewed as were the principals of their schools and some of the lecturers who had taught them Environmental Education. The implementation of Environmental Education was addressed by means of comparing the teacher's responses with Primary Environmental Education Teacher Competencies as suggested by Glasgow and Robinson (1986) and Lahiry et al (1988). The information was deduced from the teachers responses from semi-structured interviews and were qualitatively analysed.
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- Date Issued: 1992
Environmental physiology of the intertidal limpets Patella (Prosobranchia) and Siphonaria (Pulmonata)
- Authors: Marshall, David John
- Date: 1992
- Subjects: Prosobranchia Pulmonata Patellidae Siphonaria Limpets
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5686 , http://hdl.handle.net/10962/d1005372
- Description: Physiological response to environmental change is examined in species of the intertidal limpets, Patella (Prosobranchia) and Siphonaria (Pulmonata). Characteristics of heart beat were determined using impedance pneumography and these are described. Heart rate of P. granularis is related to temperature and body size, and cardiac arrest in this limpet is apparently stress-related. Siphonaria oculus may exhibit a temperature-independent, extreme, and often prolonged bradycardia (<10 beats/min). When measured shortly after aerial exposure, heart rate and oxygen consumption of the above limpet species are closely correlated. The relationships of aerial oxygen consumption with body weight and ambient temperature were determined for the above high shore species of limpet. Both have low aerial rates of oxygen consumption relative to low shore limpet species, and their QlO values decrease with increasing temperature. Diel field recordings of heart rate of S. oculus, taken during summer and winter, suggest absence of temperature acclimation, and this was also shown for oxygen consumption at high aerial temperatures (30°C) in laboratory experiments. Oxygen consumption of P. granularis is partially temperature compensated temperature acclimation). In air, even though S. oculus loses water faster, it shows greater tolerance of water loss and survives longer than P. granularis. Prolonged aerial exposure of S. oculus leads to depression of heart rate and of V02 (down to 18% of the pre-exposure rate), responses interpreted as representing adaptive metabolic rate depression. In P. granularis aerial heart rate remains constant and V02 never falls below IX 38% of pre-exposure rate. This reduction in V02 in air is considered as being stress-related, resulting from impairment of oxygen uptake. In declining oxygen tension S. capensis shows a better capacity for oxyregulation than P. granularis. On exposure to hypoxia, sand-inundation and hyposalinity, S. capensis may show typical bradycardia ( <10 beats/min), suggesting depression of aerobic metabolism, and on return to pre-exposure conditions there is no overshoot of heart rate, suggesting absence of oxygen debt. The effect of hypoxia, sand-inundation and hyposalinity on heart rate of P. granularis is variable; this becomes depressed and is often interspersed with extended cardiac arrest. When conditions are normalized, this species exhibits a clear overshoot of heart rate. The significance of differences in physiological response between patellid and siphonariid limpets is discussed with regard to their habitat segregation, particularly in the upper-shore zone (open rock and tidal pools) and sand-inundated rock substrata, where only siphonariid limpets may be found. While not previously characterized in marine gastropods, metabolic rate depression by Siphonaria, through facilitating isolation and conserving food reserves, is suggested as a key factor determining their distribution in physico-chemically more extreme and variable intertidal habitats.
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- Date Issued: 1992
Environmentalism and its implications for education: a study of private schools in the Eastern Cape
- Authors: Slade, Wilfred John
- Date: 1992
- Subjects: Environmental education -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa Private schools -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1520 , http://hdl.handle.net/10962/d1003402
- Description: This study explores the extent to which the ethos and the basic approach to education taken by three Eastern Cape private schools influences the practice of environmental education within these schools. Their environmental education programmes are evaluated in terms of the guiding principles adopted by the international community in the 'Tbilisi Principles of Environmental Education'. An ethnographic approach was adopted for this research and findings are essentially descriptive and qualitative, with special regard to social structures and the attitudes of individuals within these structures.
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- Date Issued: 1992
Evaluation of three simple hydrosalinity models applied to citrus orchards in the Lower Coerney River irrigation area, Eastern Cape, South Africa
- Authors: Cobban, Dale Anne
- Date: 1992
- Subjects: Irrigation -- Management , Irrigation -- Research -- South Africa -- Eastern Cape , Water in agriculture , Citrus -- Irrigation -- South Africa , Soils, Salts in
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4829 , http://hdl.handle.net/10962/d1005504 , Irrigation -- Management , Irrigation -- Research -- South Africa -- Eastern Cape , Water in agriculture , Citrus -- Irrigation -- South Africa , Soils, Salts in
- Description: Three hydrosalinity models of different complexity were evaluated against data from selected citrus orchards in the Lower Coerney River irrigation area. These models were statistically compared with field data, and found to vary in accuracy of output predictions. The simplest model, the LEACHING REQUIREMENT (LR) model, has the lowest data input requirements and produces output predictions that correlate with up to 93% of the variance in measured data. SODICS, which is theoretically more detailed and requires a greater level of detail in input, produces predictions of an accuracy equivalent to the LR model. The PEAK model was assessed in two parts, the PEAKM module simulating soil moisture and soil moisture movement was able to predict variations in moisture up to 99% of the time. The PEAKD module, which predicts solute concentrations was less effective in replicating real world conditions
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- Date Issued: 1992
Exploration for stratabound copper, lead and zinc deposits in the Damara-Katanga orogen, central-southern Africa
- Authors: Latorre, J J
- Date: 1992
- Subjects: Mining geology -- Research -- Africa , Copper ores -- Africa , Lead ores -- Africa , Zinc ores -- Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4946 , http://hdl.handle.net/10962/d1005558
- Description: The Damara-Katanga orogen in central-southern Africa represents an area of 1.73xl0⁶ sq. km. The region is considered one of the wealthiest metallogenic provinces in the world. Successful exploration for stratabound base-metal deposits has taken place at this particular area since the introduction of more organised methodology in the early 1920s. The genesis, location and distribution of the ore deposits are related to their tectonic settings. Geodynamic evolution of the orogen, which initially formed part of a complex Pan-African rift system, comprises the following stages rifting; downwarping, including spreading on the western portion; syn-orogeny and late-orogeny. Two major tectonic events in the history of the region have been identified: the Katangan (900-750 Ma) and the Damaran episodes (750-500 Ma). Timing of mineralisation of ore deposits has been related to the evolutionary stages of the orogen. Genetic models of the most productive deposits are briefly discussed in this dissertation. The sedimentological, geochemical, paleogeographic and structural features can be employed as geological guidelines for integrated exploration programmes. Discoveries of major deposits and prospects in the orogen are also summarised, focussing on the exploration methods employed. The cost-effective use of the exploration techniques includes the classical copper-lead-zinc soil sampling for residual soils such as those in the Copperbelt area. Airborne magnetics and electromagnetics and follow-up ground geophysics have proved successful in areas where the cover is transported in the search for shallow ore deposits such as the Matchless massive sulphides. Remote sensing, geochemical and geophysical techniques have been tried in covered areas of western Botswana. The lack of geological control makes this interpretation difficult. A detailed geological mapping and the use of geochemical and geophysical techniques has been used to delineate carbonate-hosted base-metal deposits at the Otavi Land. The more expensive traditional methods necessary for the delineation of orebodies, such as pitting, trenching and drilling, are also discussed. Using a sequential approach, a possible exploration strategy is suggested, outlining the cost-effective use of remote sensing, geochemical and geophysical techniques. Standardisation in basic geological information is required for future successful explorations in the Damara-Katanga orogen, as well as attractive mining policies. In the event of their implementation, exploration perspectives are promising, specifically in terms of ore potential.
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- Date Issued: 1992
Exploratory studies of novel ligand systems
- Authors: Taylor, Steven John
- Date: 1992
- Subjects: Ligands , Coordination compounds
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4315 , http://hdl.handle.net/10962/d1004973 , Ligands , Coordination compounds
- Description: A range of novel ligand systems have been developed in three distinct phases and preliminary studies have been initiated to evaluate their complexation potential. Phase I incorporated the synthesis of single strand ligand systems, which were mainly based on amino acid residues. Techniques have been developed for the attachment of these ligand systems onto, firstly, a styrene monomer, and then later onto a pseudo-styrene linking group, viz. the p-toluoyl group. The linking reactions were based on the formation of amides or esters by the reaction of an acid chloride system with an amine or alcohol. Phase II involved the synthesis of bis-chain ligand systems and their attachment onto the p-toluoyl linking group. A further linking group was also developed at this stage, viz. the xylyl group. In the preparation of phase II ligand systems, use was made of malonic ester and iminodiacetic acid derivatives. Phase III has involved the synthesis of cyclic ligand systems, with skeletons based upon the structures used in phase I and phase II and two crown ether type systems have been prepared.
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- Date Issued: 1992
Facies mapping of the Vaal Reef placer as an aid to remnant pillar extraction and stope width optimisation
- Authors: O'Donovan, Anthony Gareth
- Date: 1992
- Subjects: Facies (Geology) -- South Africa -- Vaal Reef placer
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4947 , http://hdl.handle.net/10962/d1005559 , Facies (Geology) -- South Africa -- Vaal Reef placer
- Description: The Vaal Reef placer is situated on the unconformable junction of the Strathmore and Stilfontein formations of the Johannesburg Subgroup. Within the South Division of the Vaal Reefs Exploration and Mining company lease, the Vaal Reef Placer is shown to be composed of several different units. Each unit exhibits its own specific characteristics and trend direction which can be used to establish distinct "Reef packages". These packages can be mapped in such a way as to provide a preliminary lithofacies map for the Vaal Reef Placer. The delineation of such geologically homogenous zones, and the development of a suitable depositional model, can be utilised in several ways. The characteristics of a particular zone are shown to influence the control of stoping width, evaluation of remnant pillars and the geostatistical methodology of evaluating current and future ore reserve blocks.
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- Date Issued: 1992
Fieldwork as a compensatory teaching strategy for rural black senior secondary schools
- Authors: Boqwana, Eleanor Pindiwe
- Date: 1992
- Subjects: Black people -- Education -- South Africa , Geography -- Fieldwork -- Study and teaching , Geography -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1544 , http://hdl.handle.net/10962/d1003426 , Black people -- Education -- South Africa , Geography -- Fieldwork -- Study and teaching , Geography -- Study and teaching -- South Africa
- Description: The understanding of geographical concepts and the development of skills requires the use of appropriate teaching strategies. Modern school syllabuses emphasize the development of concepts and skills which are basic to the understanding of geography. Geography provides practical learning opportunities which directly involve the learner. Techniques which directly involve the learner are perceived to be the most valuable. Fieldwork, which embraces a wide range of innovative teaching strategies, is the one best suited to give first-hand experience to the pupils. This study investigates the potential of fieldwork to promote conceptual understanding in geography with special reference to pupils in rural schools. Extensive literature on fieldwork in geographical education was analysed. Surveys of geography teachers and pupils in senior secondary schools were conducted to assess their attitudes towards geography and the use of learner-centred approaches with special reference to fieldwork. The role of fieldwork to promote conceptual understanding was evaluated by exposing two groups of pupils to different field activities. This revealed that fieldwork promotes understanding, stimulates interest and builds up confidence even when first introduced at senior secondary level.
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- Date Issued: 1992
Form and substance in R.M. Hare's utilitarianism
- Authors: Coetzee, Pieter Hendrik
- Date: 1992
- Subjects: Hare, R. M. (Richard Mervyn) -- Ethics , Utilitarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2706 , http://hdl.handle.net/10962/d1002836 , Hare, R. M. (Richard Mervyn) -- Ethics , Utilitarianism
- Description: Throughout his career as moral philosopher Hare has insisted that there is a rational way of arriving at substantive moral judgements. Hare develops this view - first presented in ' The language of morals' (1952) and ' Universalizability' (1955) - into the claim that rational agents are required to adopt utilitarian solutions to moral disputes. In ' Freedom and reason ' (1963) this claim is defended with reference to the view that the formal features of moral language (universalizability and prescriptivity)commit moral agents to a certain method of reasoning, and that this method of reasoning, when conjoined with facts about people's desires and preferences, leads us to accept substantive moral judgements consistent with those required by a form of utilitarianism. This view features throughout Hare's subsequent work, but the argument for it undergoes change. This means change in the defence of the claim that the meta-theory Universal Prescriptivism is consistent with a form of normative utilitarian theory, as this claim is argued for in 'Ethical theory and utilitarianism' (1976) and 'Moral Thinking' (1981). I shall endeavour to trace the chronological development of Hare's thinking, and will concentrate on developments in the argument for a theory of act-utilitarianism. I shall argue that the argument for utilitarianism gives rise to two major problems which arise from a specific feature of the argument, namely, the attempt to run the resolution of bi-lateral and multi-lateral cases of conflict along lines analogous to the resolution of conflict in the single-person case. Hare's argument requires that a decision-maker must identify the person with whom he reverses roles as himself, and that he must be prepared to concede that the things his recipient has good reasons for wanting are also reasons for him to want the same things. I argue that it is not possible to make coherent sense of the identity of the person in the reversed-role situation and that the motivational states a decision -maker is expected to deem 'his own' are not properly states of himself. If I am right, the 'identity'-question sits at the root of a motivational gap in Hare's theory.
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- Date Issued: 1992
From FidoNet to internet: the evolution of a national network
- Authors: Jacot-Guillarmod, Francois F
- Date: 1992
- Language: English
- Type: Conference paper
- Identifier: vital:6974 , http://hdl.handle.net/10962/101
- Description: The South African academic research network, UNINET-ZA, evolved within two years from a FidoNet mail gateway that distributed email via interactive Kermit links, to a dialup uucp network, to wide area TCP/IP, and finally to full Internet connectivity. While the majority of UNINET-ZA sites are now TCP/IP connected, elements of the original gatewaying techniques are still fulfilling useful functions - for example a TCP/IP <=> FidoNet gateway, and links into non-Unix, non-TCP/IP based systems.
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- Date Issued: 1992