Complex interactions involving the Cape fig, Ficus sur Forsskål, and its associated insects
- Authors: Zachariades, Costas
- Date: 1995
- Subjects: Insect-plant relationships Mutualism (Biology) Fig -- South Africa Fig wasp -- South Africa Ants Homoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5655 , http://hdl.handle.net/10962/d1005338
- Description: The inadequacy of arbitrarily classifying interactions between species as antagonistic, neutral or mutualistic has become clear in recent years. Both direct and indirect interactions between species can vary between mutualism and antagonism, depending on the intrinsic and extrinsic contexts of the interaction. This study investigated the characteristics of an ant-plant-homopteran interaction in southern Africa. The polyphagous homopteran Hilda patruelis (Tettigometridae) feeds primarily on the trunk-borne fruiting branches and figs of the Cape fig tree, Ficus sur, and produces honeydew which attracts tending ants. Ten of the sixteen ant species/species groups present on F. sur tended H. patruelis, with Pheidole megacephala the most frequent attendant. Ants attracted to F. sur by H. patruelis honeydew or other liquid food sources also preyed on insects on the tree, including adults of the small agaonid fig wasps whose larvae feed on the ovules in the developing figs. One fig wasp species (Ceratosolen capensis) is also the tree's only pollinator. No benefits to H. patruelis from being tended by ants were detected, either in terms of reduced parasitism, or predation by a lycaenid caterpillar. A P. megacephala colony foraging on a F. sur tree was found to receive a high proportion of its likely energy requirements from the tree, mainly in the form of H. patruelis honeydew, during periods when it was bearing fruit. It is probable that the H. patruelis-P. megacephala interaction constitutes a direct mutualism at times, but that benefits to the homopteran are intermittent or weak. Both H. patruelis and ants benefitted from F. sur, directly or indirectly, through the provision of food (and for some ants, nesting sites). The removal of phloem sap by H. patruelis did not detectably reduce the trees' reproductive output, either in terms of pollinator or viable seed production. The indirect effects of ant and H. patruelis presence on the F. sur trees were on average positive, as ants preyed disproportionately heavily on fig wasp species parasitic on or competing with the pollinator, thus increasing pollinator production. Effects of ant presence on seed production were not investigated, but have been demonstrated as beneficial elsewhere. However, there is great varatlon both in the composition of the wasp fauna arriving to oviposit at different crops, and in ant densities per fig, on several temporal and spatial scales. This results in high variability in the effects of ants on the pollinator and, through it, the tree, from positive to zero and potentially even negative. Despite this conditionality of beneficial outcomes for the tree, the mean effect of ants on the F. sur population studied was to increase pollinator production by up to nearly 20%. This study is among the few to have demonstrated an overall benefit to a plant of having homopteran-tending ants present on it.
- Full Text:
- Date Issued: 1995
- Authors: Zachariades, Costas
- Date: 1995
- Subjects: Insect-plant relationships Mutualism (Biology) Fig -- South Africa Fig wasp -- South Africa Ants Homoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5655 , http://hdl.handle.net/10962/d1005338
- Description: The inadequacy of arbitrarily classifying interactions between species as antagonistic, neutral or mutualistic has become clear in recent years. Both direct and indirect interactions between species can vary between mutualism and antagonism, depending on the intrinsic and extrinsic contexts of the interaction. This study investigated the characteristics of an ant-plant-homopteran interaction in southern Africa. The polyphagous homopteran Hilda patruelis (Tettigometridae) feeds primarily on the trunk-borne fruiting branches and figs of the Cape fig tree, Ficus sur, and produces honeydew which attracts tending ants. Ten of the sixteen ant species/species groups present on F. sur tended H. patruelis, with Pheidole megacephala the most frequent attendant. Ants attracted to F. sur by H. patruelis honeydew or other liquid food sources also preyed on insects on the tree, including adults of the small agaonid fig wasps whose larvae feed on the ovules in the developing figs. One fig wasp species (Ceratosolen capensis) is also the tree's only pollinator. No benefits to H. patruelis from being tended by ants were detected, either in terms of reduced parasitism, or predation by a lycaenid caterpillar. A P. megacephala colony foraging on a F. sur tree was found to receive a high proportion of its likely energy requirements from the tree, mainly in the form of H. patruelis honeydew, during periods when it was bearing fruit. It is probable that the H. patruelis-P. megacephala interaction constitutes a direct mutualism at times, but that benefits to the homopteran are intermittent or weak. Both H. patruelis and ants benefitted from F. sur, directly or indirectly, through the provision of food (and for some ants, nesting sites). The removal of phloem sap by H. patruelis did not detectably reduce the trees' reproductive output, either in terms of pollinator or viable seed production. The indirect effects of ant and H. patruelis presence on the F. sur trees were on average positive, as ants preyed disproportionately heavily on fig wasp species parasitic on or competing with the pollinator, thus increasing pollinator production. Effects of ant presence on seed production were not investigated, but have been demonstrated as beneficial elsewhere. However, there is great varatlon both in the composition of the wasp fauna arriving to oviposit at different crops, and in ant densities per fig, on several temporal and spatial scales. This results in high variability in the effects of ants on the pollinator and, through it, the tree, from positive to zero and potentially even negative. Despite this conditionality of beneficial outcomes for the tree, the mean effect of ants on the F. sur population studied was to increase pollinator production by up to nearly 20%. This study is among the few to have demonstrated an overall benefit to a plant of having homopteran-tending ants present on it.
- Full Text:
- Date Issued: 1995
A study of the personal literature written in the Eastern Cape in the nineteenth century
- Authors: Young, Cheryl Ann
- Date: 1995
- Subjects: Arkwright, Robert Wigram, 1822 -- Diaries , Armstrong, Frances -- Diaries , Bowker, Thomas Holden, 1807-1885 -- Diaries , Brownlee, James, 1824-1851 -- Diaries , Crealock, John North, 1837-1895 -- Diaries , Flanagan, Arthur Stephen -- Diaries , Hall, Henry, 1815 -- Diaries , Merriman, Nathaniel James, 1809-1881 Diaries , Pigot, Sophia, 1804-1881 -- Diaries , Stretch, Charles Lennox, 1797-1882 -- Diaries , Griffith, Patrick Raymond -- Diaries , Clergy -- South Africa -- Diaries , Diaries -- History and criticism , Soldiers -- South Africa -- Diaries , South African diaries -- History and criticism , Women -- South Africa -- Diaries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2231 , http://hdl.handle.net/10962/d1002274 , Arkwright, Robert Wigram, 1822 -- Diaries , Armstrong, Frances -- Diaries , Bowker, Thomas Holden, 1807-1885 -- Diaries , Brownlee, James, 1824-1851 -- Diaries , Crealock, John North, 1837-1895 -- Diaries , Flanagan, Arthur Stephen -- Diaries , Hall, Henry, 1815 -- Diaries , Merriman, Nathaniel James, 1809-1881 Diaries , Pigot, Sophia, 1804-1881 -- Diaries , Stretch, Charles Lennox, 1797-1882 -- Diaries , Griffith, Patrick Raymond -- Diaries , Clergy -- South Africa -- Diaries , Diaries -- History and criticism , Soldiers -- South Africa -- Diaries , South African diaries -- History and criticism , Women -- South Africa -- Diaries
- Description: The evidence of these diaries, all written in the nineteenth century, reveals the heterogeneous nature of early settler society in the Eastern Cape. Generalizations can only be of the most tenuous kind in such a small sample; but women tend to dwell on the domestic, the men on their public lives, the most reticent about their private lives are the soldiers. There is one diary which can be described as personal; the diarists did not regard their diaries as appropriate repositories of their personal triumphs and failures. The perceptions formed in Britain about the land and people of Africa are not drastically modified upon arrival unless the diarist experiences a prolongued contact with either.
- Full Text:
- Date Issued: 1995
- Authors: Young, Cheryl Ann
- Date: 1995
- Subjects: Arkwright, Robert Wigram, 1822 -- Diaries , Armstrong, Frances -- Diaries , Bowker, Thomas Holden, 1807-1885 -- Diaries , Brownlee, James, 1824-1851 -- Diaries , Crealock, John North, 1837-1895 -- Diaries , Flanagan, Arthur Stephen -- Diaries , Hall, Henry, 1815 -- Diaries , Merriman, Nathaniel James, 1809-1881 Diaries , Pigot, Sophia, 1804-1881 -- Diaries , Stretch, Charles Lennox, 1797-1882 -- Diaries , Griffith, Patrick Raymond -- Diaries , Clergy -- South Africa -- Diaries , Diaries -- History and criticism , Soldiers -- South Africa -- Diaries , South African diaries -- History and criticism , Women -- South Africa -- Diaries
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2231 , http://hdl.handle.net/10962/d1002274 , Arkwright, Robert Wigram, 1822 -- Diaries , Armstrong, Frances -- Diaries , Bowker, Thomas Holden, 1807-1885 -- Diaries , Brownlee, James, 1824-1851 -- Diaries , Crealock, John North, 1837-1895 -- Diaries , Flanagan, Arthur Stephen -- Diaries , Hall, Henry, 1815 -- Diaries , Merriman, Nathaniel James, 1809-1881 Diaries , Pigot, Sophia, 1804-1881 -- Diaries , Stretch, Charles Lennox, 1797-1882 -- Diaries , Griffith, Patrick Raymond -- Diaries , Clergy -- South Africa -- Diaries , Diaries -- History and criticism , Soldiers -- South Africa -- Diaries , South African diaries -- History and criticism , Women -- South Africa -- Diaries
- Description: The evidence of these diaries, all written in the nineteenth century, reveals the heterogeneous nature of early settler society in the Eastern Cape. Generalizations can only be of the most tenuous kind in such a small sample; but women tend to dwell on the domestic, the men on their public lives, the most reticent about their private lives are the soldiers. There is one diary which can be described as personal; the diarists did not regard their diaries as appropriate repositories of their personal triumphs and failures. The perceptions formed in Britain about the land and people of Africa are not drastically modified upon arrival unless the diarist experiences a prolongued contact with either.
- Full Text:
- Date Issued: 1995
Comprehending strike action: the South African experience c.1950-1990 and the theoretical implications thereof
- Authors: Wood, Geoffrey Thomas
- Date: 1995
- Subjects: Strikes and lockouts -- South Africa -- History Industrial relations -- South Africa -- History Labor unions -- South Africa -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3319 , http://hdl.handle.net/10962/d1003107
- Description: Regular strike action has become a central characteristic of the South African industrial relations system. Whilst in the 1950s strikes were mostly isolated outbursts of relatively short duration, strikes in the 1980s were challenges of unprecedented duration and intensity. It is argued that despite this dramatic change, reflecting a series of discontinuities in both the political and economic arenas, strike action in South Africa does follow distinct patterns, and can be ascribed to a combination of identifiable causes. Principal causal factors include wage aspirations, past experiences and the subjective interpretation thereof, and the role of the union movement. Contingent factors include the prevailing political climate, industrial relations legislation, the amount of information opposing sides possess of their adversaries' intentions as well as spatial issues, such as the internal dynamics of individual communities. Partially as a result of South Africa's political transformation, the late 1980s and early 1990s saw further changes in the industrial relations environment. Reflecting these developments, it is argued that a new type of trade unionism has developed, "coterminous unionism" . This will have far-reaching implications for the nature of industrial conflict. However, it falls fully within the theoretical parameters outlined in this thesis. Despite significant developments in social theory in the 1980s and 1990s, there have been few attempts accordingly to update theories of strike action. One of the objectives of this thesis has been to attempt such an update. It is hoped that the constructs developed will shed light on a widely prevalent form of social conflict, assist in the analysis of future outbreaks, and enable the identification of those situations where a high propensity to engage in strike action may exist.
- Full Text:
- Date Issued: 1995
- Authors: Wood, Geoffrey Thomas
- Date: 1995
- Subjects: Strikes and lockouts -- South Africa -- History Industrial relations -- South Africa -- History Labor unions -- South Africa -- History
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3319 , http://hdl.handle.net/10962/d1003107
- Description: Regular strike action has become a central characteristic of the South African industrial relations system. Whilst in the 1950s strikes were mostly isolated outbursts of relatively short duration, strikes in the 1980s were challenges of unprecedented duration and intensity. It is argued that despite this dramatic change, reflecting a series of discontinuities in both the political and economic arenas, strike action in South Africa does follow distinct patterns, and can be ascribed to a combination of identifiable causes. Principal causal factors include wage aspirations, past experiences and the subjective interpretation thereof, and the role of the union movement. Contingent factors include the prevailing political climate, industrial relations legislation, the amount of information opposing sides possess of their adversaries' intentions as well as spatial issues, such as the internal dynamics of individual communities. Partially as a result of South Africa's political transformation, the late 1980s and early 1990s saw further changes in the industrial relations environment. Reflecting these developments, it is argued that a new type of trade unionism has developed, "coterminous unionism" . This will have far-reaching implications for the nature of industrial conflict. However, it falls fully within the theoretical parameters outlined in this thesis. Despite significant developments in social theory in the 1980s and 1990s, there have been few attempts accordingly to update theories of strike action. One of the objectives of this thesis has been to attempt such an update. It is hoped that the constructs developed will shed light on a widely prevalent form of social conflict, assist in the analysis of future outbreaks, and enable the identification of those situations where a high propensity to engage in strike action may exist.
- Full Text:
- Date Issued: 1995
Petrogenesis of the New Amalfi sheet a highly differentiated Karoo intrusion
- Authors: Williams, Craig Milton
- Date: 1995
- Subjects: Petrogenesis -- South Africa -- Eastern Cape -- Karoo , Geochemistry -- South Africa -- Eastern Cape -- Karoo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4985 , http://hdl.handle.net/10962/d1005597 , Petrogenesis -- South Africa -- Eastern Cape -- Karoo , Geochemistry -- South Africa -- Eastern Cape -- Karoo
- Description: The New Amalfi Sheet is a highly differentiated tholeiitic intrusion which is situated between the towns of Matatiele and Swartberg in East Griqualand. It lies within the Central area of the Karoo Igneous Province. Rock types range from dolerites at the base and top through to a highly differentiated granophyre which is found as a 'sandwich horizon' within the top half of the sheet. The most evolved granophyre represents 15.86% of the initial liquid, which was found to be very similar in composition to the average Lesotho-type magma of Marsh and Eales (1984). The paragenetic sequence was found to be chromite → olivine → plagioclase → pigeonite and augite. Cumulus magnetite and ilmenite enter the paragenetic sequence together with immiscible sulphide droplets after 35% crystallization. In the late stages of crystallization, augite changes composition towards ferrohedenbergite. The reappearance of iron-rich olivine coincides with the disappearance of pigeonite and apatite appears as a cumulus phase for the first time after 70% crystallization. Granophyric intergrowth, which contains coarse perthitic Kfeldspar, becomes the most abundant modal entity within the most evolved granophyres. Differentiation was dominated by fractionation of plagioclase and pyroxene, with subordinate olivine and opaque-oxide fractionation. A minor amount of assimilation of country rock occurred within the topmost granophyres. The intrusion has been dated, using the Rb-Sr isochron method, at 178.37 ± 5.52 Ma. Extensive subsolidus deuteric alteration has resulted in the formation of a complete series of hydrothermally altered clinopyroxenes which are enriched in CaO but depleted in TiO₂ compared to the unaltered magmatic clinopyroxenes. It has also resulted in the formation of abundant vermiform ilmenite in the most evolved rocks, recognized by the fact that this phase is enriched in MnO compared to magmatic ilmenites. The very iron-rich orthopyroxene, ferrohypersthene, was found to have crystallized, during cooling of the sheet from the intercumulus liquid. Olivine in the dolerite re-equilibrated with the intercumulus liquid, becoming more iron-rich in composition.
- Full Text:
- Date Issued: 1995
- Authors: Williams, Craig Milton
- Date: 1995
- Subjects: Petrogenesis -- South Africa -- Eastern Cape -- Karoo , Geochemistry -- South Africa -- Eastern Cape -- Karoo
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4985 , http://hdl.handle.net/10962/d1005597 , Petrogenesis -- South Africa -- Eastern Cape -- Karoo , Geochemistry -- South Africa -- Eastern Cape -- Karoo
- Description: The New Amalfi Sheet is a highly differentiated tholeiitic intrusion which is situated between the towns of Matatiele and Swartberg in East Griqualand. It lies within the Central area of the Karoo Igneous Province. Rock types range from dolerites at the base and top through to a highly differentiated granophyre which is found as a 'sandwich horizon' within the top half of the sheet. The most evolved granophyre represents 15.86% of the initial liquid, which was found to be very similar in composition to the average Lesotho-type magma of Marsh and Eales (1984). The paragenetic sequence was found to be chromite → olivine → plagioclase → pigeonite and augite. Cumulus magnetite and ilmenite enter the paragenetic sequence together with immiscible sulphide droplets after 35% crystallization. In the late stages of crystallization, augite changes composition towards ferrohedenbergite. The reappearance of iron-rich olivine coincides with the disappearance of pigeonite and apatite appears as a cumulus phase for the first time after 70% crystallization. Granophyric intergrowth, which contains coarse perthitic Kfeldspar, becomes the most abundant modal entity within the most evolved granophyres. Differentiation was dominated by fractionation of plagioclase and pyroxene, with subordinate olivine and opaque-oxide fractionation. A minor amount of assimilation of country rock occurred within the topmost granophyres. The intrusion has been dated, using the Rb-Sr isochron method, at 178.37 ± 5.52 Ma. Extensive subsolidus deuteric alteration has resulted in the formation of a complete series of hydrothermally altered clinopyroxenes which are enriched in CaO but depleted in TiO₂ compared to the unaltered magmatic clinopyroxenes. It has also resulted in the formation of abundant vermiform ilmenite in the most evolved rocks, recognized by the fact that this phase is enriched in MnO compared to magmatic ilmenites. The very iron-rich orthopyroxene, ferrohypersthene, was found to have crystallized, during cooling of the sheet from the intercumulus liquid. Olivine in the dolerite re-equilibrated with the intercumulus liquid, becoming more iron-rich in composition.
- Full Text:
- Date Issued: 1995
The analysis of a computer music network and the implementation of essential subsystems
- Authors: Wilks, Antony John
- Date: 1995
- Subjects: Computer networks , Computer music , MIDI (Standard)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4666 , http://hdl.handle.net/10962/d1006682 , Computer networks , Computer music , MIDI (Standard)
- Description: The inability to share resources in commercial and institutional computer music studios results in non-optimal resource utilisation. The use of computers to process, store and communicate data can be extended within these studios, to provide the capability of sharing resources amongst their users. This thesis describes a computer music network which was designed for this purpose. Certain devices had to be custom built for the implementation of the network. The thesis discusses the design and construction of these devices.
- Full Text:
- Date Issued: 1995
- Authors: Wilks, Antony John
- Date: 1995
- Subjects: Computer networks , Computer music , MIDI (Standard)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4666 , http://hdl.handle.net/10962/d1006682 , Computer networks , Computer music , MIDI (Standard)
- Description: The inability to share resources in commercial and institutional computer music studios results in non-optimal resource utilisation. The use of computers to process, store and communicate data can be extended within these studios, to provide the capability of sharing resources amongst their users. This thesis describes a computer music network which was designed for this purpose. Certain devices had to be custom built for the implementation of the network. The thesis discusses the design and construction of these devices.
- Full Text:
- Date Issued: 1995
An investigation of reactions directed towards the synthesis of 2-methyl-2-(methylthio)propanal oxime
- Authors: Whittaker, Ruth Eleanor
- Date: 1995
- Subjects: Pesticides -- Synthesis , Insecticides , Aldicarb -- Synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4322 , http://hdl.handle.net/10962/d1004980 , Pesticides -- Synthesis , Insecticides , Aldicarb -- Synthesis
- Description: The processes leading to the formation of 2-methyl-2-(methylthio)propanal oxime, known industrially as aldicarb oxime, have been studied. The three stages of the synthesis, viz., chlorination, thiomethylation and oximation have been thoroughly investigated, with the aim of optimising the yield and purity of aldicarb oxime. Attention has been focused on the chlorination step, and the effects of altering various conditions have been determined; the reaction has been carried out in the absence and presence of heat, solvent and buffer, and the extent of chlorine addition has also been varied. These studies have led to some improvement in the yield for this step. Several simple and inexpensive methods for purifying contaminated batches of aldicarb oxime have also been examined. Possible aldicarb oxime contaminants, identified by GLC and GC-MS analysis, have been synthesised for use as chromatographic and spectroscopic standards, and confirmation of the presence of a number of these contaminants has been achieved. Aldehyde trimers have been found to be the primary contaminants present in aldicarb oxime and the thermal stability of these trimers, their corresponding monomers and aldicarb oxime itself has been studied using variable temperature ¹H NMR spectroscopy. Novel pyridine derivatives, with potential as aldicarb analogues, have been synthesised and characterised using spectroscopic methods.
- Full Text:
- Date Issued: 1995
- Authors: Whittaker, Ruth Eleanor
- Date: 1995
- Subjects: Pesticides -- Synthesis , Insecticides , Aldicarb -- Synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4322 , http://hdl.handle.net/10962/d1004980 , Pesticides -- Synthesis , Insecticides , Aldicarb -- Synthesis
- Description: The processes leading to the formation of 2-methyl-2-(methylthio)propanal oxime, known industrially as aldicarb oxime, have been studied. The three stages of the synthesis, viz., chlorination, thiomethylation and oximation have been thoroughly investigated, with the aim of optimising the yield and purity of aldicarb oxime. Attention has been focused on the chlorination step, and the effects of altering various conditions have been determined; the reaction has been carried out in the absence and presence of heat, solvent and buffer, and the extent of chlorine addition has also been varied. These studies have led to some improvement in the yield for this step. Several simple and inexpensive methods for purifying contaminated batches of aldicarb oxime have also been examined. Possible aldicarb oxime contaminants, identified by GLC and GC-MS analysis, have been synthesised for use as chromatographic and spectroscopic standards, and confirmation of the presence of a number of these contaminants has been achieved. Aldehyde trimers have been found to be the primary contaminants present in aldicarb oxime and the thermal stability of these trimers, their corresponding monomers and aldicarb oxime itself has been studied using variable temperature ¹H NMR spectroscopy. Novel pyridine derivatives, with potential as aldicarb analogues, have been synthesised and characterised using spectroscopic methods.
- Full Text:
- Date Issued: 1995
Secondary school geography teachers' perceptions of the role of environmental education in geography with particular reference to Natal Education Department teachers
- Wassermann, Johannes Michiel
- Authors: Wassermann, Johannes Michiel
- Date: 1995
- Subjects: Geography teachers -- South Africa -- KwaZulu-Natal -- Attitudes Environmental education -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1761 , http://hdl.handle.net/10962/d1003646
- Description: Environmental Education (EE) as a development cannot be ignored by Geography or Geographers particularly since South Africa, as the rest of the world, is confronted by a looming environmental crisis. Geography is an environmental science concerned primarily with man-environment relationships using an environmental approach to develop the skills, knowledge, values and attitudes necessary for sustainable living. Geography has a vital role to play in addressing environmental issues. In formal education Geography teachers will be responsible for the implementation of such an approach. This study therefore investigates the perceptions of Natal Senior Secondary School Geography teachers regarding the role of EE in Geography. Questionnaires and semi-structured interviews were used to determine this. The study revealed that although these teachers are well qualified and motivated they had a limited grasp of the theory underpinning current EE and Geographical thinking. Recommendations are made for the development of an environmental approach in the teaching of Geography.
- Full Text:
- Date Issued: 1995
- Authors: Wassermann, Johannes Michiel
- Date: 1995
- Subjects: Geography teachers -- South Africa -- KwaZulu-Natal -- Attitudes Environmental education -- South Africa -- KwaZulu-Natal
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1761 , http://hdl.handle.net/10962/d1003646
- Description: Environmental Education (EE) as a development cannot be ignored by Geography or Geographers particularly since South Africa, as the rest of the world, is confronted by a looming environmental crisis. Geography is an environmental science concerned primarily with man-environment relationships using an environmental approach to develop the skills, knowledge, values and attitudes necessary for sustainable living. Geography has a vital role to play in addressing environmental issues. In formal education Geography teachers will be responsible for the implementation of such an approach. This study therefore investigates the perceptions of Natal Senior Secondary School Geography teachers regarding the role of EE in Geography. Questionnaires and semi-structured interviews were used to determine this. The study revealed that although these teachers are well qualified and motivated they had a limited grasp of the theory underpinning current EE and Geographical thinking. Recommendations are made for the development of an environmental approach in the teaching of Geography.
- Full Text:
- Date Issued: 1995
HPLC analysis and pharmacokinetics of cyclizine
- Authors: Walker, Roderick Bryan
- Date: 1995
- Subjects: High performance liquid chromatography Piperazine Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3801 , http://hdl.handle.net/10962/d1003279
- Description: The investigations detailed in this dissertation have been conducted to address the paucity of pharmacokinetic information, in published literature, pertaining to cyclizine. The areas of investigation have included the selective quantitation of both cyclizine and its demethylated metabolite, norcyclizine in serum and urine, assessment of stability of both compounds in stored biological samples, dosage form analysis, dissolution rate testing of tablets, and bioavailability and pharmacokinetics following administration of an intravenous solution, and tablets to humans. High-performance liquid chromatography (HPLC) was used as the main analytical technique throughout these studies. An original HPLC method employing ultraviolet detection with a limit of quantitation of 5μg/ℓ was developed for the determination of cyclizine in serum and both cyclizine and norcyclizine in urine, Solid-phase extraction using extraction columns packed with reversed-phase C18 material, and followed by a simple phase-separation step proved successful for the accurate and precise isolation of the compounds. The validated method was applied to the analysis of serum and urine samples from a pilot study in which a single volunteer was administered 50mg of cyclizine hydrochloride. Several samples collected during the pilot study revealed the presence of both drug and metabolite in concentrations below the limit of detection. In order to improve the selectivity and sensitivity of the analytical method an HPLC method with electrochemical detection operating in the "oxidative-screen" mode was developed. The solid-phase extraction procedure was modified slightly and the method found to be precise, accurate, selective and highly sensitive with a limit of quantitation of Iμg/g/l for both cyclizine and norcyclizine in both serum and urine. This method was applied to the determination of both compounds after intravenous and oral administration of cyclizine to humans. HPLC with electrochemical detection was used for the analysis of samples collected during dissolution studies on the batch of tablets used for pharmacokinetic studies. In addition, this method was used to assess content uniformity of the tablets and of samples from the batch of intravenous ampoules of cyclizine lactate. Dissolution studies showed that all tablets tested passed the compendial specifications for cyclizine. Content uniformity assessment revealed that within-batch uniformity existed for both the tablets and ampoules and, therefore, variations in pharmacokinetic parameters for the drug would more than likely be as a result of inter- and intra-individual variability within the subject population. Pharmacokinetic information for cyclizine was obtained following administration of an intravenous bolus dose of cyclizine lactate as a solution, oral administration of cyclizine hydrochloride as a single dose of 50mg and as fixed multiple doses of 50mg every 8 hours for five days. Further information was acquired following administration of single doses of 100mg and 150mg cyclizine hydrochloride. Data collected from these studies were evaluated using both compartmental and non-compartmental techniques. Cyclizine was rapidly absorbed following oral administration with mean kₐ = 1.54 hr⁻¹ and was found to have an absolute bioavailability (F) of 0.47. The presence of norcyclizine in serum following oral and not intravenous dosing suggests cyclizine is susceptible to "first-pass" metabolism in either the gut wall or the I iver. Mean ClTOT determined following the intravenous dose was 0.865 ℓ/hr/kg. The mean ClTOT of 0.823 ℓ/hr/kg calculated following oral dosing, using a unique value of F for each subject compared favourahly with that obtained following intravenous dosing. Renal clearance of cyclizine is negligihle indicating that non-renal routes of elimination account for the majority of removal of cyclizine form the body. Cyclizine is extensively distributed and the mean Vz following an intravenous dose was 16.70 ℓ/kg. This value is lower than that calculated from all oral studies from which the mean Vz was determined to be 25.74 ℓ/kg. Cyclizine is eliminated slowly with a mean elimination t½ = 20.11 hours. Cyclizine dose not appear to follow dosedependent kinetics and therefore, inability to predict steady state levels are more than likely due to accumulation as a result of frequent dosing rather than saturation of elimination mechanisms. Modelling of intravenous data to one-compartment (lBCM), two-compartment (2BCM) and threecompartment models indicated that the pharmacokinetics of cyclizine can be adequately described by a 3BCM. The drug is rapidly distributed into a "shallow" peripheral compartment (α = 9.44 hr⁻¹ , and k₂₁ = 2.09 hr⁻¹ ), and slowly distributed to the "deep" peripheral compartment (β = 0.451 hr⁻¹ and k₃₁ = 0.120 hr⁻¹ ). Modelling of all oral data indicated that a 2BCM best described the pharmacokinetics of the drug, however, distribution to the peripheral compartment is not as rapid as to the "shallow" peripheral compartment following the intravenous dose. Mean distribution parameters were α = 0.64 hr⁻¹1 and, k₂₁ = 0.39 hr⁻¹. Mean CITOT following intravenous dosing of 0.70 ℓ/hr/kg was similar to the mean CIToT of 0.73 ℓ/hr/kg determined after oral dosing. The mean distribution volume at steady state determined following intravenous dosing (17.78 ℓ/kg) was lower than that obtained from the oral studies (25.52 ℓ/kg). The mean terminal elimination half-lives calculated for cyclizine following fitting of intravenous and oral data was 25.09 hours. In general, mean pharmacokinetic parameters calculated following titting of data to a 2BCM after oral administration correlate closely with those calculated using non-compartmental techniques. However, the pharmacokinetics following intravenous dosing are better described by a 3BCM and a close correlation between parameters estimated using noncompartmental techniques and compartmental techniques is evident when a 3BCM model is used.
- Full Text:
- Date Issued: 1995
- Authors: Walker, Roderick Bryan
- Date: 1995
- Subjects: High performance liquid chromatography Piperazine Pharmacokinetics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3801 , http://hdl.handle.net/10962/d1003279
- Description: The investigations detailed in this dissertation have been conducted to address the paucity of pharmacokinetic information, in published literature, pertaining to cyclizine. The areas of investigation have included the selective quantitation of both cyclizine and its demethylated metabolite, norcyclizine in serum and urine, assessment of stability of both compounds in stored biological samples, dosage form analysis, dissolution rate testing of tablets, and bioavailability and pharmacokinetics following administration of an intravenous solution, and tablets to humans. High-performance liquid chromatography (HPLC) was used as the main analytical technique throughout these studies. An original HPLC method employing ultraviolet detection with a limit of quantitation of 5μg/ℓ was developed for the determination of cyclizine in serum and both cyclizine and norcyclizine in urine, Solid-phase extraction using extraction columns packed with reversed-phase C18 material, and followed by a simple phase-separation step proved successful for the accurate and precise isolation of the compounds. The validated method was applied to the analysis of serum and urine samples from a pilot study in which a single volunteer was administered 50mg of cyclizine hydrochloride. Several samples collected during the pilot study revealed the presence of both drug and metabolite in concentrations below the limit of detection. In order to improve the selectivity and sensitivity of the analytical method an HPLC method with electrochemical detection operating in the "oxidative-screen" mode was developed. The solid-phase extraction procedure was modified slightly and the method found to be precise, accurate, selective and highly sensitive with a limit of quantitation of Iμg/g/l for both cyclizine and norcyclizine in both serum and urine. This method was applied to the determination of both compounds after intravenous and oral administration of cyclizine to humans. HPLC with electrochemical detection was used for the analysis of samples collected during dissolution studies on the batch of tablets used for pharmacokinetic studies. In addition, this method was used to assess content uniformity of the tablets and of samples from the batch of intravenous ampoules of cyclizine lactate. Dissolution studies showed that all tablets tested passed the compendial specifications for cyclizine. Content uniformity assessment revealed that within-batch uniformity existed for both the tablets and ampoules and, therefore, variations in pharmacokinetic parameters for the drug would more than likely be as a result of inter- and intra-individual variability within the subject population. Pharmacokinetic information for cyclizine was obtained following administration of an intravenous bolus dose of cyclizine lactate as a solution, oral administration of cyclizine hydrochloride as a single dose of 50mg and as fixed multiple doses of 50mg every 8 hours for five days. Further information was acquired following administration of single doses of 100mg and 150mg cyclizine hydrochloride. Data collected from these studies were evaluated using both compartmental and non-compartmental techniques. Cyclizine was rapidly absorbed following oral administration with mean kₐ = 1.54 hr⁻¹ and was found to have an absolute bioavailability (F) of 0.47. The presence of norcyclizine in serum following oral and not intravenous dosing suggests cyclizine is susceptible to "first-pass" metabolism in either the gut wall or the I iver. Mean ClTOT determined following the intravenous dose was 0.865 ℓ/hr/kg. The mean ClTOT of 0.823 ℓ/hr/kg calculated following oral dosing, using a unique value of F for each subject compared favourahly with that obtained following intravenous dosing. Renal clearance of cyclizine is negligihle indicating that non-renal routes of elimination account for the majority of removal of cyclizine form the body. Cyclizine is extensively distributed and the mean Vz following an intravenous dose was 16.70 ℓ/kg. This value is lower than that calculated from all oral studies from which the mean Vz was determined to be 25.74 ℓ/kg. Cyclizine is eliminated slowly with a mean elimination t½ = 20.11 hours. Cyclizine dose not appear to follow dosedependent kinetics and therefore, inability to predict steady state levels are more than likely due to accumulation as a result of frequent dosing rather than saturation of elimination mechanisms. Modelling of intravenous data to one-compartment (lBCM), two-compartment (2BCM) and threecompartment models indicated that the pharmacokinetics of cyclizine can be adequately described by a 3BCM. The drug is rapidly distributed into a "shallow" peripheral compartment (α = 9.44 hr⁻¹ , and k₂₁ = 2.09 hr⁻¹ ), and slowly distributed to the "deep" peripheral compartment (β = 0.451 hr⁻¹ and k₃₁ = 0.120 hr⁻¹ ). Modelling of all oral data indicated that a 2BCM best described the pharmacokinetics of the drug, however, distribution to the peripheral compartment is not as rapid as to the "shallow" peripheral compartment following the intravenous dose. Mean distribution parameters were α = 0.64 hr⁻¹1 and, k₂₁ = 0.39 hr⁻¹. Mean CITOT following intravenous dosing of 0.70 ℓ/hr/kg was similar to the mean CIToT of 0.73 ℓ/hr/kg determined after oral dosing. The mean distribution volume at steady state determined following intravenous dosing (17.78 ℓ/kg) was lower than that obtained from the oral studies (25.52 ℓ/kg). The mean terminal elimination half-lives calculated for cyclizine following fitting of intravenous and oral data was 25.09 hours. In general, mean pharmacokinetic parameters calculated following titting of data to a 2BCM after oral administration correlate closely with those calculated using non-compartmental techniques. However, the pharmacokinetics following intravenous dosing are better described by a 3BCM and a close correlation between parameters estimated using noncompartmental techniques and compartmental techniques is evident when a 3BCM model is used.
- Full Text:
- Date Issued: 1995
Sensitive high-performance liquid chromatographic determination of cyclizine and its demethylated metabolite, norcyclizine, in biological fluids using coulometric detection
- Walker, Roderick B, Kanfer, Isadore
- Authors: Walker, Roderick B , Kanfer, Isadore
- Date: 1995
- Language: English
- Type: text , Article
- Identifier: vital:6452 , http://hdl.handle.net/10962/d1006640 , http://dx.doi.org/10.1016/0378-4347(95)00202-T
- Description: An accurate, sensitive, selective and reproducible high-performance liquid chromatographic method with coulometric detection for the determination of cyclizine and its inactive demethylated metabolite, norcyclizine, in biological fluids has been developed. The drugs were separated using a custom packed reversed-phase C18 analytical column and phosphate buffer (0.05 M, pH 3)-acetonitrile (7:3) as mobile phase. The dual electrode coulometric detector was operated in the "oxidative-screen" mode with the upstream electrode (detector 1) set at 0.55 V and the downstream electrode (detector 2) set at 0.90 V. Serum and urine samples were prepared for analysis by solid-phase extraction, followed by a simple phase-separation step. The limit of quantitation was 1 ng/ml for both cyclizine and norcyclizine in serum and urine.
- Full Text:
- Date Issued: 1995
- Authors: Walker, Roderick B , Kanfer, Isadore
- Date: 1995
- Language: English
- Type: text , Article
- Identifier: vital:6452 , http://hdl.handle.net/10962/d1006640 , http://dx.doi.org/10.1016/0378-4347(95)00202-T
- Description: An accurate, sensitive, selective and reproducible high-performance liquid chromatographic method with coulometric detection for the determination of cyclizine and its inactive demethylated metabolite, norcyclizine, in biological fluids has been developed. The drugs were separated using a custom packed reversed-phase C18 analytical column and phosphate buffer (0.05 M, pH 3)-acetonitrile (7:3) as mobile phase. The dual electrode coulometric detector was operated in the "oxidative-screen" mode with the upstream electrode (detector 1) set at 0.55 V and the downstream electrode (detector 2) set at 0.90 V. Serum and urine samples were prepared for analysis by solid-phase extraction, followed by a simple phase-separation step. The limit of quantitation was 1 ng/ml for both cyclizine and norcyclizine in serum and urine.
- Full Text:
- Date Issued: 1995
Intercultural communication on a passenger aircraft flight deck: a qualitative study set in the context of South African corporate affirmative action policy
- Authors: Waite, Michele Jeannette
- Date: 1995
- Subjects: Intercultural communication South Africa , Language and culture South Africa , Communication and culture South Africa , Affirmative action programs South Africa , Air pilots South Africa Language , Flight crews South Africa Language ,
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3082 , http://hdl.handle.net/10962/d1002591
- Description: The recent emphasis on Affirmative Action policies in South African corporations has illuminated the issue of cultural diversity in organizations and the difficulties arising from this transition and change. One such difficulty is the problem of intercultural communication where miscommunication can have life-threatening consequences. This problem is particularly critical in the operational environment of the passenger aircraft flight deck where small group factors, as well as intercultural issues must be taken into account. In this thesis the problem of intercultural communication in such contexts as a consequence of Affirmative Action is examined. The data for this thesis comprises the communication of five culturally diverse flight crews. A multi-method was used for the gathering and analysis of this data. This involved the use of video-taped flight simulator sessions, and personal interviews with each crew member. The subjects themselves were involved in identifying key communication problems from the video and interpretation of the data. Three levels of analysis were used in the interpretation of the findings - the individual, the group and the organization. The factors which affected communication at each level in the small, culturally diverse group are highlighted. Furthermore, factors which influence the climate in which communication takes place are also considered. The implications for Affirmative Action are discussed.
- Full Text:
- Date Issued: 1995
- Authors: Waite, Michele Jeannette
- Date: 1995
- Subjects: Intercultural communication South Africa , Language and culture South Africa , Communication and culture South Africa , Affirmative action programs South Africa , Air pilots South Africa Language , Flight crews South Africa Language ,
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3082 , http://hdl.handle.net/10962/d1002591
- Description: The recent emphasis on Affirmative Action policies in South African corporations has illuminated the issue of cultural diversity in organizations and the difficulties arising from this transition and change. One such difficulty is the problem of intercultural communication where miscommunication can have life-threatening consequences. This problem is particularly critical in the operational environment of the passenger aircraft flight deck where small group factors, as well as intercultural issues must be taken into account. In this thesis the problem of intercultural communication in such contexts as a consequence of Affirmative Action is examined. The data for this thesis comprises the communication of five culturally diverse flight crews. A multi-method was used for the gathering and analysis of this data. This involved the use of video-taped flight simulator sessions, and personal interviews with each crew member. The subjects themselves were involved in identifying key communication problems from the video and interpretation of the data. Three levels of analysis were used in the interpretation of the findings - the individual, the group and the organization. The factors which affected communication at each level in the small, culturally diverse group are highlighted. Furthermore, factors which influence the climate in which communication takes place are also considered. The implications for Affirmative Action are discussed.
- Full Text:
- Date Issued: 1995
Alternative dispute resolution in the best interests of the child
- Authors: Van Zyl, Lesbury
- Date: 1995
- Subjects: Divorce mediation -- South Africa , Dispute resolution (Law) -- South Africa , Custody of children -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3697 , http://hdl.handle.net/10962/d1003212 , Divorce mediation -- South Africa , Dispute resolution (Law) -- South Africa , Custody of children -- South Africa
- Description: The development of private divorce mediation appears to offer a friendly and informal alternative to the "hostile" adversarial divorce. A close analysis of its claims, however, shows them to be largely unproven. Urgent attention should therefore be given to the philosophical base of the movement. There is also a need for empirical research and for standardised training. Further unanswered questions relate to the part to be played by different professions, and to professional ethics. It is submitted that the appointment of Family Advocates is a step in the right direction but that the establishment of a full Family Court will best protect children's interests.
- Full Text:
- Date Issued: 1995
- Authors: Van Zyl, Lesbury
- Date: 1995
- Subjects: Divorce mediation -- South Africa , Dispute resolution (Law) -- South Africa , Custody of children -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3697 , http://hdl.handle.net/10962/d1003212 , Divorce mediation -- South Africa , Dispute resolution (Law) -- South Africa , Custody of children -- South Africa
- Description: The development of private divorce mediation appears to offer a friendly and informal alternative to the "hostile" adversarial divorce. A close analysis of its claims, however, shows them to be largely unproven. Urgent attention should therefore be given to the philosophical base of the movement. There is also a need for empirical research and for standardised training. Further unanswered questions relate to the part to be played by different professions, and to professional ethics. It is submitted that the appointment of Family Advocates is a step in the right direction but that the establishment of a full Family Court will best protect children's interests.
- Full Text:
- Date Issued: 1995
Environmental education and research in southern Africa: a landscape of shifting priorities
- Authors: Van Rensburg, Eureta Janse
- Date: 1995
- Subjects: Environmental education -- Research -- South Africa Environmental sciences -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1513 , http://hdl.handle.net/10962/d1003395
- Description: What has come to be labelled as 'the environment crisis' has roots in the structures and orientations of modern societies. True to our modernist ways we call on, or offer, education and research, experts and science, to address our socio-ecological concerns. This study set out to identify research priorities in environmental education from within the institutional setting of a university and within the context of environmental and political change in southern Africa and epistemological shifts in educational research traditions. The emergent research design allowed for a progressive clarification of theoretical vantage point: from an instrumental listing of priorities, through the participatory development of a critical and consensual framework for research, to a reflexive description of a landscape of shifting priorities. I collected data over a 3-year period, in inter alia 38 semi-structured interviews, workshops with some 150 participants, focus group discussions, documents and conferences. Participants' professional contexts included environmental education, natural resource management, social and biophysical sciences, development, formal and non-formal education, funding agencies, academic and non-academic settings. My engagement with the emerging discourses revealed patterns and inconsistencies in participants' views on research, environmental education, change and research priorities. I identified three orientations - Research for Management to Restore Order to Nature and Society, Research to Resolve Practitioners' and Communities' Problems, and Research for Radical Reconstruction - in the emerging landscape. These orientations were accompanied by change models and themes (discourses of difference and 'othering', instrumental views of education and research and accumulative knowledge, a conceptual theory-practice gap) which limited their potential for transformation towards sustainable living. They presented solutions cut from the same modernist cloth as the environment crisis. An emerging Reflexive perspective in and on environmental education research showed potential as a transitionary orientation outside modernist assumptions. I outline research priorities from this perspective. Reflexivity reveals the myths of expert-driven, instrumental and institutionalised research separated from environmental education and based upon rationalistic interpretations of science. It opens up possibilities for transformative knowledge emerging from 're-search' based versions of education as a process of, rather than a means to, social change.
- Full Text:
- Date Issued: 1995
- Authors: Van Rensburg, Eureta Janse
- Date: 1995
- Subjects: Environmental education -- Research -- South Africa Environmental sciences -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1513 , http://hdl.handle.net/10962/d1003395
- Description: What has come to be labelled as 'the environment crisis' has roots in the structures and orientations of modern societies. True to our modernist ways we call on, or offer, education and research, experts and science, to address our socio-ecological concerns. This study set out to identify research priorities in environmental education from within the institutional setting of a university and within the context of environmental and political change in southern Africa and epistemological shifts in educational research traditions. The emergent research design allowed for a progressive clarification of theoretical vantage point: from an instrumental listing of priorities, through the participatory development of a critical and consensual framework for research, to a reflexive description of a landscape of shifting priorities. I collected data over a 3-year period, in inter alia 38 semi-structured interviews, workshops with some 150 participants, focus group discussions, documents and conferences. Participants' professional contexts included environmental education, natural resource management, social and biophysical sciences, development, formal and non-formal education, funding agencies, academic and non-academic settings. My engagement with the emerging discourses revealed patterns and inconsistencies in participants' views on research, environmental education, change and research priorities. I identified three orientations - Research for Management to Restore Order to Nature and Society, Research to Resolve Practitioners' and Communities' Problems, and Research for Radical Reconstruction - in the emerging landscape. These orientations were accompanied by change models and themes (discourses of difference and 'othering', instrumental views of education and research and accumulative knowledge, a conceptual theory-practice gap) which limited their potential for transformation towards sustainable living. They presented solutions cut from the same modernist cloth as the environment crisis. An emerging Reflexive perspective in and on environmental education research showed potential as a transitionary orientation outside modernist assumptions. I outline research priorities from this perspective. Reflexivity reveals the myths of expert-driven, instrumental and institutionalised research separated from environmental education and based upon rationalistic interpretations of science. It opens up possibilities for transformative knowledge emerging from 're-search' based versions of education as a process of, rather than a means to, social change.
- Full Text:
- Date Issued: 1995
The mineralogy and geochemistry of the Voëlwater banded iron-formation, Northern Cape Province
- Authors: Tsikos, Harilaos
- Date: 1995
- Subjects: Mineralogy -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4977 , http://hdl.handle.net/10962/d1005589 , Mineralogy -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Description: Banded iron-formations (BIFs) are chemically precipitated sedimentary rocks in which Fe-rich bands or laminae alternate with Fe-poor ones. They formed within a specific time-span of the geological record. Their occurrence is restricted between 2.3 and 1.9 Ga, and characterises virtually all the major Precambrian-aged sedimentary basins of the world. The Precambrian Transvaal Basin in Griqualand West, South Africa, is noted for its well-developed BIF units. The Kuruman and Griquatown BIFs comprising the Asbesheuwels Subgroup (up to 1000m thick) are the best known and thickest of these. As far as metallogenesis is concerned, the Kuruman BIF is of major importance, for it carries the world's largest crocidolite (blue asbestos) deposits. The uppermost, youngest member of iron-formation deposition in the Griqualand West Sequence is represented by the Voëlwater BIF. The direct association between the latter and the giant Mn-deposits of the Kalahari Field, renders the Voëlwater association unusual, if not unique, in the geological record. The Voëlwater BIF represents a typical example of the so-called "Superior-type", and in the area of study it has undergone late-diagennetic to low-grade metamorphic processes. This is evident from the mineralogical composition and textural signature of the various BIF lithologies. Specifically, the minerals that make up the Voëlwater BIF are mainly chert(quartz), Fe-oxides (magnetite and hematite), Fe-silicates (greenalite, stilpnomelane, minnesotaite, riebeckite, Fe-mica), Fe-carbonates (members of the dolomite-ankerite series and siderite), calcite and pyrite. Soft-sediment deformation structures and shear-stress indicators are abundant in carbonate-rich and granular, silicate-rich BIF lithologies respectively. The bulk chemical composition of the study rocks is relatively simple and is characterised by the abundance of essentially three elements, namely Si, Fe, and Ca, which make up more than 90% of the total chemical composition of the Voëlwater BIFs. The detrital component of the study rocks is negligible. Mn-enrichments characterise all the transitional lithologies towards the interbedded Mn-orebodies, as well as the well-developed, hematitic BIF-unit between the Ongeluk lavas and the lower Mn-horizon. In terms of trace element composition, no significant enrichments or depletions, were encountered, except for some unusually high values of Sr and Ba and Co in carbonate-rich and Mn-rich lithologies respectively. Geochemical comparisons on the basis of major, trace and light rare-earth element composition verified the similarity between the Voëlwater BIF and other major Superior-type BIFs of the world (e.g. Kuruman, Griquatown, Sokoman, Biwabik, Gunflint, Mara-Mamba, Brockman, etc.). The processes that led to the formation of the Voëlwater BIFs may have been very similar to the ones described in various genetic models proposed in recent years. They would have involved a combination of: i. hydrothermal processes related to mid-ocean ridge (MOR) or hot-spot activity that acted as major iron suppliers; ii. storm-mixing in stratified oceans (bottom, anoxic, Fe⁺² reservoir-thermo- pycnocline zone-upper, mixed, SiO₂-saturated layer), largely dictated by seasonal changes and contemporaneous volcanism; iii. periodic, convection-driven upwelling mechanisms acting as major Fe-precipitators; and, iv. organic carbon productivity that was responsible for the anoxic diagenesis of the initial sediment. However, the origin of Fe and Mn for the genesis of the Voëlwater sediments was difficult to explain with typical convection-cell models in active mid-ocean ridges, in contrast to previous hypotheses. Instead, large-scale endogenous processes in the form of magma convection, underplating, differentiation and associated degassing, may have played a critical role in the supply of metals for the formation of large amounts of BIFs in the Precambrian. The present study of the Voëlwater BIF also bears strong implications regarding the metallogenesis of Mn in the Precambrian. The common association of Mn with carbonate-bearing sediments, the transitional character of the Voëlwater BIF towards carbonate lithologies (Mooidraai dolomites) and the critical timing of the deposition of the former in terms of the Precambrian atmospheric-lithospheric- hydrospheric evolution, may be important indicators for the exploration of large Mn-deposits in Precambrian sedimentary basins of the world.
- Full Text:
- Date Issued: 1995
- Authors: Tsikos, Harilaos
- Date: 1995
- Subjects: Mineralogy -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4977 , http://hdl.handle.net/10962/d1005589 , Mineralogy -- South Africa -- Northern Cape , Geochemistry -- South Africa -- Northern Cape , Geology -- South Africa -- Northern Cape
- Description: Banded iron-formations (BIFs) are chemically precipitated sedimentary rocks in which Fe-rich bands or laminae alternate with Fe-poor ones. They formed within a specific time-span of the geological record. Their occurrence is restricted between 2.3 and 1.9 Ga, and characterises virtually all the major Precambrian-aged sedimentary basins of the world. The Precambrian Transvaal Basin in Griqualand West, South Africa, is noted for its well-developed BIF units. The Kuruman and Griquatown BIFs comprising the Asbesheuwels Subgroup (up to 1000m thick) are the best known and thickest of these. As far as metallogenesis is concerned, the Kuruman BIF is of major importance, for it carries the world's largest crocidolite (blue asbestos) deposits. The uppermost, youngest member of iron-formation deposition in the Griqualand West Sequence is represented by the Voëlwater BIF. The direct association between the latter and the giant Mn-deposits of the Kalahari Field, renders the Voëlwater association unusual, if not unique, in the geological record. The Voëlwater BIF represents a typical example of the so-called "Superior-type", and in the area of study it has undergone late-diagennetic to low-grade metamorphic processes. This is evident from the mineralogical composition and textural signature of the various BIF lithologies. Specifically, the minerals that make up the Voëlwater BIF are mainly chert(quartz), Fe-oxides (magnetite and hematite), Fe-silicates (greenalite, stilpnomelane, minnesotaite, riebeckite, Fe-mica), Fe-carbonates (members of the dolomite-ankerite series and siderite), calcite and pyrite. Soft-sediment deformation structures and shear-stress indicators are abundant in carbonate-rich and granular, silicate-rich BIF lithologies respectively. The bulk chemical composition of the study rocks is relatively simple and is characterised by the abundance of essentially three elements, namely Si, Fe, and Ca, which make up more than 90% of the total chemical composition of the Voëlwater BIFs. The detrital component of the study rocks is negligible. Mn-enrichments characterise all the transitional lithologies towards the interbedded Mn-orebodies, as well as the well-developed, hematitic BIF-unit between the Ongeluk lavas and the lower Mn-horizon. In terms of trace element composition, no significant enrichments or depletions, were encountered, except for some unusually high values of Sr and Ba and Co in carbonate-rich and Mn-rich lithologies respectively. Geochemical comparisons on the basis of major, trace and light rare-earth element composition verified the similarity between the Voëlwater BIF and other major Superior-type BIFs of the world (e.g. Kuruman, Griquatown, Sokoman, Biwabik, Gunflint, Mara-Mamba, Brockman, etc.). The processes that led to the formation of the Voëlwater BIFs may have been very similar to the ones described in various genetic models proposed in recent years. They would have involved a combination of: i. hydrothermal processes related to mid-ocean ridge (MOR) or hot-spot activity that acted as major iron suppliers; ii. storm-mixing in stratified oceans (bottom, anoxic, Fe⁺² reservoir-thermo- pycnocline zone-upper, mixed, SiO₂-saturated layer), largely dictated by seasonal changes and contemporaneous volcanism; iii. periodic, convection-driven upwelling mechanisms acting as major Fe-precipitators; and, iv. organic carbon productivity that was responsible for the anoxic diagenesis of the initial sediment. However, the origin of Fe and Mn for the genesis of the Voëlwater sediments was difficult to explain with typical convection-cell models in active mid-ocean ridges, in contrast to previous hypotheses. Instead, large-scale endogenous processes in the form of magma convection, underplating, differentiation and associated degassing, may have played a critical role in the supply of metals for the formation of large amounts of BIFs in the Precambrian. The present study of the Voëlwater BIF also bears strong implications regarding the metallogenesis of Mn in the Precambrian. The common association of Mn with carbonate-bearing sediments, the transitional character of the Voëlwater BIF towards carbonate lithologies (Mooidraai dolomites) and the critical timing of the deposition of the former in terms of the Precambrian atmospheric-lithospheric- hydrospheric evolution, may be important indicators for the exploration of large Mn-deposits in Precambrian sedimentary basins of the world.
- Full Text:
- Date Issued: 1995
Reactions of iron- and zinc-fuelled pyrotechnic systems
- Authors: Tribelhorn, Michael John
- Date: 1995
- Subjects: Detonators Peroxides Chemistry, Analytic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4341 , http://hdl.handle.net/10962/d1005003
- Description: A major industrial use of pyrotechnic compositions is as delay fuses in electric detonators. Suitable delay times may be achieved through (i) choice of chemical components (ii) adjustment of composition of the system chosen and, finally, (iii) adjustment of the length of fuse used. This study forms part of a survey of binary fuel/oxidant combinations in an attempt to provide some fundamental information on the first step above: (i) choice of chemical components. The complete survey has included studies of a single fuel in combination with one of a variety of oxidants, and studies of the oxidation of one of several different fuels separately by barium peroxide and strontium peroxide. This study is part of this second approach and the fuels chosen were iron and zinc powders, mainly for chemical reasons (including the potential for use of thermomagnetometry on the iron systems), but also for possible environmental advantages. The mixed oxide products of pyrotechnic combustion could also have some scientific and/or commercial value. The techniques used included thermal analyses of mixtures and their individual components, and measurements of temperature-time profiles during combustion. Thermodynamic and kinetic information was obtained under a variety of conditions and scanning electron microscopy and X-ray diffraction and microprobe analyses provided additional information. Possible mechanisms of reactions are discussed in detail. The practical conclusions were that any potential use which the Fe/peroxide systems may have as delay compositions, with burning-rates of from 3-30 mm s⁻¹, is offset by the susceptibility of the oxidants to reaction with water and CO₂ in the atmosphere. The Zn/BaO₂ and Zn/SrO₂ systems did not burn under compaction, and combustion of uncompacted powders was erratic. Zinc liquid (and probably zinc vapour) take part in the reaction and the gaseous nature of the combustion makes zinc-fuelled pyrotechnic systems unsuitable for delay applications. All the techniques used showed the heterogeneity of the solid residues of combustion. If these residues were to be of any value, they would need further conventional treatment involving grinding of the residue, possible adjustment of compositions, and calcining to produce uniform materials.
- Full Text:
- Date Issued: 1995
- Authors: Tribelhorn, Michael John
- Date: 1995
- Subjects: Detonators Peroxides Chemistry, Analytic
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4341 , http://hdl.handle.net/10962/d1005003
- Description: A major industrial use of pyrotechnic compositions is as delay fuses in electric detonators. Suitable delay times may be achieved through (i) choice of chemical components (ii) adjustment of composition of the system chosen and, finally, (iii) adjustment of the length of fuse used. This study forms part of a survey of binary fuel/oxidant combinations in an attempt to provide some fundamental information on the first step above: (i) choice of chemical components. The complete survey has included studies of a single fuel in combination with one of a variety of oxidants, and studies of the oxidation of one of several different fuels separately by barium peroxide and strontium peroxide. This study is part of this second approach and the fuels chosen were iron and zinc powders, mainly for chemical reasons (including the potential for use of thermomagnetometry on the iron systems), but also for possible environmental advantages. The mixed oxide products of pyrotechnic combustion could also have some scientific and/or commercial value. The techniques used included thermal analyses of mixtures and their individual components, and measurements of temperature-time profiles during combustion. Thermodynamic and kinetic information was obtained under a variety of conditions and scanning electron microscopy and X-ray diffraction and microprobe analyses provided additional information. Possible mechanisms of reactions are discussed in detail. The practical conclusions were that any potential use which the Fe/peroxide systems may have as delay compositions, with burning-rates of from 3-30 mm s⁻¹, is offset by the susceptibility of the oxidants to reaction with water and CO₂ in the atmosphere. The Zn/BaO₂ and Zn/SrO₂ systems did not burn under compaction, and combustion of uncompacted powders was erratic. Zinc liquid (and probably zinc vapour) take part in the reaction and the gaseous nature of the combustion makes zinc-fuelled pyrotechnic systems unsuitable for delay applications. All the techniques used showed the heterogeneity of the solid residues of combustion. If these residues were to be of any value, they would need further conventional treatment involving grinding of the residue, possible adjustment of compositions, and calcining to produce uniform materials.
- Full Text:
- Date Issued: 1995
A comparison of the reproductive strategies of key species of a prograding dune system in the Mlalazi Nature Reserve, Natal
- Authors: Todd, Colleen Barbara
- Date: 1995
- Subjects: Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4231 , http://hdl.handle.net/10962/d1003800 , Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Description: The succession on the dunes of the Mlalazi Nature Reserve represents a classical example of primary succession. The reproductive strategies of eight key species were compared to determine some of the mechanisms affecting the community dynamics, at the population level, in the early stages of succession. There is a temporal separation in the flowering and fruiting phenologies. Passerina rigida, Stipagrostis zeyheri and Imperata cylindrica produced small seeds with a low fruit/seed mass ratio within a short cycle. The seeds are suitable for wind-dispersal. The animal-dispersed species; Eugenia capensis, Mimusops caffra and Scaevola plumieri, produced large fleshy seeds with a high fruit/seed mass ratio within cycles of six months and more. Chrysanthemoides monilifera, also an animal-dispersed species, produced a large quantity of small fleshy seeds throughout the year. The fern, Microsorium scolopendrium produced spores throughout the year. The staggered fruiting and flowering phenology ensures a year-round availability of fruit in the dunefield. The key species formed less than half of the species composition of the soil seed bank. The size and range of the soil seed bank differed between the species. P. rigida and S. plumieri formed a high proportion of the seeds in the soil with a wide distribution along the successional gradient. The other species had low soil seed densities with short distribution ranges, or were not present. P. rigida and S. plumieri are easily dispersed species, whereas the other species may have a more restricted and clumped distribution due to the effect of foragers. A high density of P. rigida and E. capensis seeds were found under the parent trees. Only seeds of P. rigida and S. zeyheri were found in the soil in the open. Seeds of P. rigida, S. zeyheri, E. capensis and M. caffra were found under the canopies of P. rigida, E. capensis and M. caffra. No seeds of C. monilifera and I. cylindrica were found in the soil, possibly due to predation. The period of the study (September 1991 to November 1992) was in a dry or drought cycle with only 56.8% of the mean annual rainfall falling. Seed germination and seedling survival of all the species were affected by these dry, warm climatic conditions. The species had seedling densities of less than 4 seeds/m². The environmental conditions along the successional gradient also had an effect on seed germination and seedling survival. Environmental factors of soil pH, light intensity and surface soil temperatures were higher in the open than under canopy. Soil pH and the understorey cover decreased as the light intensity decreased from under the canopy of P. rigida to M. caffra . Litter cover and plant height increased. E. capensis had measurements intermediate to the two species, but had higher surface soil temperatures and plant height than P. rigida. Seedlings of P. rigida in the open and under the canopy of the parent plants had died by the end of the monitoring period. 50% of the seedlings of S. zeyheri under the canopy of P. rigida and M. caffra died. The mortality rate of the seedlings of E. capensis was lower under M. caffra than under the parent plants. I. cylindrica may be propagated vegetatively. However, the mortality of the propagules was greater under the canopy of E. capensis than under P. rigida. M. caffra only germinated under the canopy of E. capensis with a 100% mortality of the seedlings. M. scolopendrium only produced propagules through vegetative propagation under the canopy of E. capensis and M. caffra. The mortality of the young ferns was less than 50% and less under M. caffra than under E. capensis. No seedlings of C. monilifera or S. plumieri were found. The seed distribution range, seed germination requirements and the effect of the environmental conditions on the germination of the seeds and seedling establishment of the species appear to important factors of the reproductive strategies regulating the size of the species populations along the successional gradient.
- Full Text:
- Date Issued: 1995
- Authors: Todd, Colleen Barbara
- Date: 1995
- Subjects: Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4231 , http://hdl.handle.net/10962/d1003800 , Sand dune plants -- South Africa -- KwaZulu-Natal -- Mlalazi Nature Reserve , Sand dune plants Comparative studies
- Description: The succession on the dunes of the Mlalazi Nature Reserve represents a classical example of primary succession. The reproductive strategies of eight key species were compared to determine some of the mechanisms affecting the community dynamics, at the population level, in the early stages of succession. There is a temporal separation in the flowering and fruiting phenologies. Passerina rigida, Stipagrostis zeyheri and Imperata cylindrica produced small seeds with a low fruit/seed mass ratio within a short cycle. The seeds are suitable for wind-dispersal. The animal-dispersed species; Eugenia capensis, Mimusops caffra and Scaevola plumieri, produced large fleshy seeds with a high fruit/seed mass ratio within cycles of six months and more. Chrysanthemoides monilifera, also an animal-dispersed species, produced a large quantity of small fleshy seeds throughout the year. The fern, Microsorium scolopendrium produced spores throughout the year. The staggered fruiting and flowering phenology ensures a year-round availability of fruit in the dunefield. The key species formed less than half of the species composition of the soil seed bank. The size and range of the soil seed bank differed between the species. P. rigida and S. plumieri formed a high proportion of the seeds in the soil with a wide distribution along the successional gradient. The other species had low soil seed densities with short distribution ranges, or were not present. P. rigida and S. plumieri are easily dispersed species, whereas the other species may have a more restricted and clumped distribution due to the effect of foragers. A high density of P. rigida and E. capensis seeds were found under the parent trees. Only seeds of P. rigida and S. zeyheri were found in the soil in the open. Seeds of P. rigida, S. zeyheri, E. capensis and M. caffra were found under the canopies of P. rigida, E. capensis and M. caffra. No seeds of C. monilifera and I. cylindrica were found in the soil, possibly due to predation. The period of the study (September 1991 to November 1992) was in a dry or drought cycle with only 56.8% of the mean annual rainfall falling. Seed germination and seedling survival of all the species were affected by these dry, warm climatic conditions. The species had seedling densities of less than 4 seeds/m². The environmental conditions along the successional gradient also had an effect on seed germination and seedling survival. Environmental factors of soil pH, light intensity and surface soil temperatures were higher in the open than under canopy. Soil pH and the understorey cover decreased as the light intensity decreased from under the canopy of P. rigida to M. caffra . Litter cover and plant height increased. E. capensis had measurements intermediate to the two species, but had higher surface soil temperatures and plant height than P. rigida. Seedlings of P. rigida in the open and under the canopy of the parent plants had died by the end of the monitoring period. 50% of the seedlings of S. zeyheri under the canopy of P. rigida and M. caffra died. The mortality rate of the seedlings of E. capensis was lower under M. caffra than under the parent plants. I. cylindrica may be propagated vegetatively. However, the mortality of the propagules was greater under the canopy of E. capensis than under P. rigida. M. caffra only germinated under the canopy of E. capensis with a 100% mortality of the seedlings. M. scolopendrium only produced propagules through vegetative propagation under the canopy of E. capensis and M. caffra. The mortality of the young ferns was less than 50% and less under M. caffra than under E. capensis. No seedlings of C. monilifera or S. plumieri were found. The seed distribution range, seed germination requirements and the effect of the environmental conditions on the germination of the seeds and seedling establishment of the species appear to important factors of the reproductive strategies regulating the size of the species populations along the successional gradient.
- Full Text:
- Date Issued: 1995
Bacterial interaction in hide biodeterioration with special reference to selected Clostridium species
- Authors: Thompson, Gillian Ann
- Date: 1995
- Subjects: Hides and skins -- Preservation Aerobic bacteria Pseudomonas aeruginosa Clostridium Halobacterium
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4041 , http://hdl.handle.net/10962/d1004102
- Description: Animal hides are the basic raw material of the leather industry and they undergo rapid putrefaction unless "cured". This study investigated the role and interactive effects of three selected bacteria, Pseudomonas aeruginosa. Clostridium histoly ticum and Clostridium sporogenes in in-situ cattle hide degradation using a model system set up for the purpose. The system consisted of 3cm diameter hide pieces contained in sealed jars and sterilised by ethylene oxide to remove resident microbes and inactivate autolytic tissue enzymes. The inocula were prepared either as individual cultures or as combinations of two inocula or all three inocula. Degradative changes during storage at 30°C were measured for up to 8 days using ten different parameters. Initial trials confirmed that the selected inocula were readily isolated from raw hides and could outcompete resident populations to produce putrefactive decomposition. Growth rates and enzyme profiles of the organisms and the effects of nutrients and reductants on their relative denaturative effects were used to standardise the system. Trials on the effects of ethylene oxide indicated the suitability of the method for hide and collagen sterilisation. The findings of in-situ trials with the selected inocula confirmed previous studies of protein putrefaction in that a bacterial succession was evident involving aerobic proteolytic bacteria, micro-aerophilic proteolytic bacteria and strictly anaerobic amino acid degrading bacteria. However, this study showed that the micro-aerophilic collagenase producing C. histolyticum degraded hides at a far greater rate when inoculated on its own than when in the presence of either or both of the other two inocula. It also demonstrated a bacterial antagonism between the two clostridia in which C. sporogenes prevented degradative changes occurring for up to 4-6 days possibly due to cysteine production by C. sporogenes. These findings have implications for hide preservation since maintenance of aerobic conditions and suppression of spore outgrowth could be used to delay growth of collagenase producing clostridia. The use of C. sporogenes as a biocontrol agent is also postulated. The model system was also used to examine salted hides during storage and these studies indicated that Halobacteriaceae do not produce collagenase but that inadequately salted hides could possibly be subject to degradation by delsulfovibrios.
- Full Text:
- Date Issued: 1995
- Authors: Thompson, Gillian Ann
- Date: 1995
- Subjects: Hides and skins -- Preservation Aerobic bacteria Pseudomonas aeruginosa Clostridium Halobacterium
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4041 , http://hdl.handle.net/10962/d1004102
- Description: Animal hides are the basic raw material of the leather industry and they undergo rapid putrefaction unless "cured". This study investigated the role and interactive effects of three selected bacteria, Pseudomonas aeruginosa. Clostridium histoly ticum and Clostridium sporogenes in in-situ cattle hide degradation using a model system set up for the purpose. The system consisted of 3cm diameter hide pieces contained in sealed jars and sterilised by ethylene oxide to remove resident microbes and inactivate autolytic tissue enzymes. The inocula were prepared either as individual cultures or as combinations of two inocula or all three inocula. Degradative changes during storage at 30°C were measured for up to 8 days using ten different parameters. Initial trials confirmed that the selected inocula were readily isolated from raw hides and could outcompete resident populations to produce putrefactive decomposition. Growth rates and enzyme profiles of the organisms and the effects of nutrients and reductants on their relative denaturative effects were used to standardise the system. Trials on the effects of ethylene oxide indicated the suitability of the method for hide and collagen sterilisation. The findings of in-situ trials with the selected inocula confirmed previous studies of protein putrefaction in that a bacterial succession was evident involving aerobic proteolytic bacteria, micro-aerophilic proteolytic bacteria and strictly anaerobic amino acid degrading bacteria. However, this study showed that the micro-aerophilic collagenase producing C. histolyticum degraded hides at a far greater rate when inoculated on its own than when in the presence of either or both of the other two inocula. It also demonstrated a bacterial antagonism between the two clostridia in which C. sporogenes prevented degradative changes occurring for up to 4-6 days possibly due to cysteine production by C. sporogenes. These findings have implications for hide preservation since maintenance of aerobic conditions and suppression of spore outgrowth could be used to delay growth of collagenase producing clostridia. The use of C. sporogenes as a biocontrol agent is also postulated. The model system was also used to examine salted hides during storage and these studies indicated that Halobacteriaceae do not produce collagenase but that inadequately salted hides could possibly be subject to degradation by delsulfovibrios.
- Full Text:
- Date Issued: 1995
A case for geography in South African senior primary schools: an analysis and evaluation of current geographical thinking and practice
- Authors: Taylor, Simon Michael
- Date: 1995
- Subjects: Geography -- Study and teaching (Elementary) -- South Africa -- Evaluation Geography teachers -- South Africa -- Attitudes Geography -- Study and teaching (Elementary) -- Curricula -- Comparative studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1428 , http://hdl.handle.net/10962/d1003309
- Description: Geography faces several challenges in a changing South Africa. These include the challenge to initiate a primary curriculum that helps to provide a foundation for sustainable living in a society that faces serious problems of unemployment, violence, irreparable damage to the environment and the lack of housing, water and basic services for the majority of the population. This thesis attempts to provide a case for geography in the primary school by examining the value of the subject for pupils' development and by reviewing the strengths and weaknesses of an integrated approach in view of the possible introduction of an integrated primary curriculum in South Africa. The second aspect of the study is concerned with a survey of teachers in the Natal Education Department to evaluate the perceived value of geography as a subject and support for geography as a discrete subject. The main thrust of geography in the primary school is to develop concepts, skills, values and attitudes that allow pupils to be more understanding and caring about the local and global environment, about people, communities, species and the natural environment on which we all depend. The results of the survey reveal that teachers support geography as a discrete subject with an intra-curriculum approach. The introduction of an integrated core curriculum in South Africa would prove problematic as teachers are not in favour of an integrated approach across the curriculum. The lack of teacher support in Kenya for an integrated curriculum was one of the main reasons for its failure. Hopefully South Africa will learn from other countries experiences with introducing an integrated curriculum. Teachers value the role of geography in the education of the child and suggest the introduction of environmental and development themes to make the subject more relevant to children's lives. The syllabus analysis revealed that a unified pnmary curriculum is required which is influenced by the needs of society in South Africa. Recommendations are made regarding ideas for a future primary curriculum.
- Full Text:
- Date Issued: 1995
- Authors: Taylor, Simon Michael
- Date: 1995
- Subjects: Geography -- Study and teaching (Elementary) -- South Africa -- Evaluation Geography teachers -- South Africa -- Attitudes Geography -- Study and teaching (Elementary) -- Curricula -- Comparative studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1428 , http://hdl.handle.net/10962/d1003309
- Description: Geography faces several challenges in a changing South Africa. These include the challenge to initiate a primary curriculum that helps to provide a foundation for sustainable living in a society that faces serious problems of unemployment, violence, irreparable damage to the environment and the lack of housing, water and basic services for the majority of the population. This thesis attempts to provide a case for geography in the primary school by examining the value of the subject for pupils' development and by reviewing the strengths and weaknesses of an integrated approach in view of the possible introduction of an integrated primary curriculum in South Africa. The second aspect of the study is concerned with a survey of teachers in the Natal Education Department to evaluate the perceived value of geography as a subject and support for geography as a discrete subject. The main thrust of geography in the primary school is to develop concepts, skills, values and attitudes that allow pupils to be more understanding and caring about the local and global environment, about people, communities, species and the natural environment on which we all depend. The results of the survey reveal that teachers support geography as a discrete subject with an intra-curriculum approach. The introduction of an integrated core curriculum in South Africa would prove problematic as teachers are not in favour of an integrated approach across the curriculum. The lack of teacher support in Kenya for an integrated curriculum was one of the main reasons for its failure. Hopefully South Africa will learn from other countries experiences with introducing an integrated curriculum. Teachers value the role of geography in the education of the child and suggest the introduction of environmental and development themes to make the subject more relevant to children's lives. The syllabus analysis revealed that a unified pnmary curriculum is required which is influenced by the needs of society in South Africa. Recommendations are made regarding ideas for a future primary curriculum.
- Full Text:
- Date Issued: 1995
Physiological, perceptual and performance responses to competitive stress in individual and team sports among youth sport participants
- Authors: Swart, Kamilla
- Date: 1995
- Subjects: Sports -- Psychological aspects , Competition (Psychology) in adolescence -- Testing , Stress in adolescence -- Testing , Anxiety in adolescence -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5169 , http://hdl.handle.net/10962/d1016257
- Description: Due to limited research in the field testing of youth sport, specifically with regard to females, this project was delimited to the examination of the responses of youth participants in relation to the nature of the sport, when participating under conditions of competitive stress. It further attempted to elucidate gender related differences within these responses. Forty four male and female subjects aged 15 - 19 years volunteered to participate in this study; all pupils were First team members who competed in a variety of team and individual sports. Subjects participated in a battery of psychological, physiological and performance tests before and after competing in a practice session and during competitive league matches. The data were statistically analyzed for the various parameters under investigation. The results of the Sport Competition Anxiety Test indicated that the females, and the male team players had the highest competitive anxiety traits (CTA). The Task and Ego Orientation in Sport Questionnaire scores showed that most subjects have a general dominance of task orientation to sport. The results of the Physical Self-Perception Profile revealed that the females' poorer perception of their physical was not as substantial as their difference in CTA compared to males. Team participants, particularly the males, had a poorer self-image than individual sport counterparts. Elevated heart rate responses were observed prior to performing in a competitive ambience, with significant increases in team, rather than individual, players. The Evaluation of Task Demands revealed that team players, especially the females, perceived the match demands as significantly higher than the individual athletes. No significant differences were observed in the players' Evaluation of Perceived Strain. Neither were any significant differences observed in the players' ratings of their performance. In conclusion, although differences appear to exist between male and female responses within a competitive ambience, the magnitude of difference was far more notable between team and individual responses to competitive stress, particularly for competitive matches as opposed to practice sessions.
- Full Text:
- Date Issued: 1995
- Authors: Swart, Kamilla
- Date: 1995
- Subjects: Sports -- Psychological aspects , Competition (Psychology) in adolescence -- Testing , Stress in adolescence -- Testing , Anxiety in adolescence -- Testing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5169 , http://hdl.handle.net/10962/d1016257
- Description: Due to limited research in the field testing of youth sport, specifically with regard to females, this project was delimited to the examination of the responses of youth participants in relation to the nature of the sport, when participating under conditions of competitive stress. It further attempted to elucidate gender related differences within these responses. Forty four male and female subjects aged 15 - 19 years volunteered to participate in this study; all pupils were First team members who competed in a variety of team and individual sports. Subjects participated in a battery of psychological, physiological and performance tests before and after competing in a practice session and during competitive league matches. The data were statistically analyzed for the various parameters under investigation. The results of the Sport Competition Anxiety Test indicated that the females, and the male team players had the highest competitive anxiety traits (CTA). The Task and Ego Orientation in Sport Questionnaire scores showed that most subjects have a general dominance of task orientation to sport. The results of the Physical Self-Perception Profile revealed that the females' poorer perception of their physical was not as substantial as their difference in CTA compared to males. Team participants, particularly the males, had a poorer self-image than individual sport counterparts. Elevated heart rate responses were observed prior to performing in a competitive ambience, with significant increases in team, rather than individual, players. The Evaluation of Task Demands revealed that team players, especially the females, perceived the match demands as significantly higher than the individual athletes. No significant differences were observed in the players' Evaluation of Perceived Strain. Neither were any significant differences observed in the players' ratings of their performance. In conclusion, although differences appear to exist between male and female responses within a competitive ambience, the magnitude of difference was far more notable between team and individual responses to competitive stress, particularly for competitive matches as opposed to practice sessions.
- Full Text:
- Date Issued: 1995
The small business entrepreneur : a psychological profile
- Authors: Street, David Michael
- Date: 1995
- Subjects: Businessmen -- Psychology , Businesswomen -- Psychology , Self-employed -- Psychology , Entrepreneurship -- Psychological aspects , Small business -- Psychological aspects , Businessmen , Businesswomen , Businesspeople
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:3065 , http://hdl.handle.net/10962/d1002574 , Businessmen -- Psychology , Businesswomen -- Psychology , Self-employed -- Psychology , Entrepreneurship -- Psychological aspects , Small business -- Psychological aspects , Businessmen , Businesswomen , Businesspeople
- Description: With the growing importance being placed on the small business environment as having a positive influence on economic growth and vitality (Erwee, 1987: Burns & Dewhurst, 1989), there has been a corresponding increase in attention being paid to entrepreneurship and the characteristics of the entrepreneur. This increased attention is due to the fact that entrepreneurs have long been linked to small business creation and recognised as an important factor in the small business development process (Boyd & Gumpert, 1983). Despite the quantity of research on entrepreneurship, there appears to be an ongoing controversy oyer what characterises an entrepreneurial business. and the specific characteristics of the small business entrepreneur. It has been argued that although there is an overlap between entrepreneurial and non-entrepreneurial businesses. they are in fact different entities (Carland, Hoy, Boulton & Carland, 1984: Drucker, 1985), and that not every individual who starts a business is an entrepreneur (Drucker. 1985). Small business entrepreneurship has been found to be specifically related to the psychological characteristics of the owner-manager who controls the business (Miller. 1983). The purpose of this research was to identify and describe psychological characteristics displayed by a group of South African small business entrepreneurs, thereby compiling a psychological profile of the small business entrepreneur. Given the nature of entrepreneurial activities and processes, Hofer and Bygrave (1992) recommend that accurate, precise qualitative data that is rich in its descriptive characterisation of the situation and the phenomenon involved be collected. As a result the researcher used qualitative rather than quantitative methods of investigation. Innovative behaviour has long been linked to entrepreneurship (Schumpeter. 1934) and entrepreneurial businesses were distinguished from other small businesses by their use of innovative strategic practices. Two sample groups consisting of entrepreneurial and non-entrepreneurial businesses, were created and the data collected were analysed independently. The results, based on personal interviews with 32 small business owner-managers and the administration and interpretation of tihe Structured Objective Rorschach Test (SORT), indicate that small business entrepreneurship should not be used as a term synonymous with small business ownership and/or management. Despite similarities between small business entrepreneurs and other small business owner-managers. the results suggest that a distinction between the two groups is necessary for accurate future research on entrepreneurs. The entrepreneurs differed from other small business owner-managers in terms of their psychological characteristics including their motives, their perception and attitude towards the external environment, and various sociological factors. The entrepreneurial businesses were also different in that they were more innovative and growth oriented than the non-entrepreneurial businesses. The research contributes towards a clarification of the concept of small business entrepreneurship and indicates a need for more precise sampling techniques to be used in entrepreneurial research.
- Full Text:
- Date Issued: 1995
- Authors: Street, David Michael
- Date: 1995
- Subjects: Businessmen -- Psychology , Businesswomen -- Psychology , Self-employed -- Psychology , Entrepreneurship -- Psychological aspects , Small business -- Psychological aspects , Businessmen , Businesswomen , Businesspeople
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:3065 , http://hdl.handle.net/10962/d1002574 , Businessmen -- Psychology , Businesswomen -- Psychology , Self-employed -- Psychology , Entrepreneurship -- Psychological aspects , Small business -- Psychological aspects , Businessmen , Businesswomen , Businesspeople
- Description: With the growing importance being placed on the small business environment as having a positive influence on economic growth and vitality (Erwee, 1987: Burns & Dewhurst, 1989), there has been a corresponding increase in attention being paid to entrepreneurship and the characteristics of the entrepreneur. This increased attention is due to the fact that entrepreneurs have long been linked to small business creation and recognised as an important factor in the small business development process (Boyd & Gumpert, 1983). Despite the quantity of research on entrepreneurship, there appears to be an ongoing controversy oyer what characterises an entrepreneurial business. and the specific characteristics of the small business entrepreneur. It has been argued that although there is an overlap between entrepreneurial and non-entrepreneurial businesses. they are in fact different entities (Carland, Hoy, Boulton & Carland, 1984: Drucker, 1985), and that not every individual who starts a business is an entrepreneur (Drucker. 1985). Small business entrepreneurship has been found to be specifically related to the psychological characteristics of the owner-manager who controls the business (Miller. 1983). The purpose of this research was to identify and describe psychological characteristics displayed by a group of South African small business entrepreneurs, thereby compiling a psychological profile of the small business entrepreneur. Given the nature of entrepreneurial activities and processes, Hofer and Bygrave (1992) recommend that accurate, precise qualitative data that is rich in its descriptive characterisation of the situation and the phenomenon involved be collected. As a result the researcher used qualitative rather than quantitative methods of investigation. Innovative behaviour has long been linked to entrepreneurship (Schumpeter. 1934) and entrepreneurial businesses were distinguished from other small businesses by their use of innovative strategic practices. Two sample groups consisting of entrepreneurial and non-entrepreneurial businesses, were created and the data collected were analysed independently. The results, based on personal interviews with 32 small business owner-managers and the administration and interpretation of tihe Structured Objective Rorschach Test (SORT), indicate that small business entrepreneurship should not be used as a term synonymous with small business ownership and/or management. Despite similarities between small business entrepreneurs and other small business owner-managers. the results suggest that a distinction between the two groups is necessary for accurate future research on entrepreneurs. The entrepreneurs differed from other small business owner-managers in terms of their psychological characteristics including their motives, their perception and attitude towards the external environment, and various sociological factors. The entrepreneurial businesses were also different in that they were more innovative and growth oriented than the non-entrepreneurial businesses. The research contributes towards a clarification of the concept of small business entrepreneurship and indicates a need for more precise sampling techniques to be used in entrepreneurial research.
- Full Text:
- Date Issued: 1995
An exploratory survey of the needs and adjustment to retirement of persons residing in Port Alfred
- Authors: Stephens, Brent William
- Date: 1995
- Subjects: Retirement, Places of -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Social conditions , Older people -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Economic conditions , Retirees -- South Africa -- Eastern Cape -- Port Alfred
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3283 , http://hdl.handle.net/10962/d1006514 , Retirement, Places of -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Social conditions , Older people -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Economic conditions , Retirees -- South Africa -- Eastern Cape -- Port Alfred
- Description: The problem that was chosen to be investigated, was that, within the white middle class South African white-collar worker there appears to be a tendency to live for the "pie in the sky" - which for most seems to be retirement to the idyllic cottage by the sea. Within the South African scenario, there seems to be a definite lack of career planning or at least planning for retirement, other than the financial emphasis. Upon reaching the "ultimate" retirement, retirees take their pension money and move to the coast, expecting pure bliss. The result of their lack of forethought is that they settle in a totally different climate, away from the support of family and friends, possibly finding their income inadequate, with the result that many fall seriously ill, and then discover a lack of geriatric care or a hospital at the time in their lives when they need it the most. The aim of the research was to investigate these issues using a specific location - Port Alfred, researching the fact that Port Alfred continues to be a retirement haven, despite appearing to lack the necessary facilities required by the elderly. The method of the research was to initially administer a pilot questionnaire to a few elderly residents at random, which was then followed up by the formal personally administered questionnaire to a sample. The sample of retired elderly residents in Port Alfred was chosen at random primarily from the various old age homes in Port Alfred. This questionnaire was administered in 1983 but due to financial and personal reasons, the results were not written up. In 1990, the research was continued with a further questionnaire being administered in 1991. The research direction was altered slightly to identify not only what resources were felt to be lacking, but also to identify how well the retired persons of Port Alfred had managed their transition to retirement. The results showed some similarity between the 1983 and the 1991 research. On the surface the retirees appeared well-adjusted and content, but when it was delved deeper, they appeared to have opted out of making any great effort to change their situation, but rather had taken the view that they had earned their rest, would make the best of what they had, and leave it to someone else to champion their cause. This meant that they relied heavily upon those in their community to meet their obvious needs. The promised hospital that they had arduously raised funds for had not materialised, and that seemed to have been the last effort that they had been prepared to make, they were now at rest. The conclusion was that, although the retirees had made the best of their situation, this definitely did not mean that their resources were adequate. Various charities and social services were at work in the community to redress the imbalance, but it was felt that these would in turn benefit by the addition of a social worker. This social worker would coordinate these services and take responsibility for the community at large, particularly addressing the need to unify the services with those to the large non-White community, in the (on-going) development of the New South Africa
- Full Text:
- Date Issued: 1995
- Authors: Stephens, Brent William
- Date: 1995
- Subjects: Retirement, Places of -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Social conditions , Older people -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Economic conditions , Retirees -- South Africa -- Eastern Cape -- Port Alfred
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3283 , http://hdl.handle.net/10962/d1006514 , Retirement, Places of -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Social conditions , Older people -- South Africa -- Eastern Cape -- Port Alfred , Older people -- South Africa -- Eastern Cape -- Port Alfred -- Economic conditions , Retirees -- South Africa -- Eastern Cape -- Port Alfred
- Description: The problem that was chosen to be investigated, was that, within the white middle class South African white-collar worker there appears to be a tendency to live for the "pie in the sky" - which for most seems to be retirement to the idyllic cottage by the sea. Within the South African scenario, there seems to be a definite lack of career planning or at least planning for retirement, other than the financial emphasis. Upon reaching the "ultimate" retirement, retirees take their pension money and move to the coast, expecting pure bliss. The result of their lack of forethought is that they settle in a totally different climate, away from the support of family and friends, possibly finding their income inadequate, with the result that many fall seriously ill, and then discover a lack of geriatric care or a hospital at the time in their lives when they need it the most. The aim of the research was to investigate these issues using a specific location - Port Alfred, researching the fact that Port Alfred continues to be a retirement haven, despite appearing to lack the necessary facilities required by the elderly. The method of the research was to initially administer a pilot questionnaire to a few elderly residents at random, which was then followed up by the formal personally administered questionnaire to a sample. The sample of retired elderly residents in Port Alfred was chosen at random primarily from the various old age homes in Port Alfred. This questionnaire was administered in 1983 but due to financial and personal reasons, the results were not written up. In 1990, the research was continued with a further questionnaire being administered in 1991. The research direction was altered slightly to identify not only what resources were felt to be lacking, but also to identify how well the retired persons of Port Alfred had managed their transition to retirement. The results showed some similarity between the 1983 and the 1991 research. On the surface the retirees appeared well-adjusted and content, but when it was delved deeper, they appeared to have opted out of making any great effort to change their situation, but rather had taken the view that they had earned their rest, would make the best of what they had, and leave it to someone else to champion their cause. This meant that they relied heavily upon those in their community to meet their obvious needs. The promised hospital that they had arduously raised funds for had not materialised, and that seemed to have been the last effort that they had been prepared to make, they were now at rest. The conclusion was that, although the retirees had made the best of their situation, this definitely did not mean that their resources were adequate. Various charities and social services were at work in the community to redress the imbalance, but it was felt that these would in turn benefit by the addition of a social worker. This social worker would coordinate these services and take responsibility for the community at large, particularly addressing the need to unify the services with those to the large non-White community, in the (on-going) development of the New South Africa
- Full Text:
- Date Issued: 1995