Controls on the distribution of manganese in banded iron-formations (BIF) of the palaeoproterozoic transvaal supergroup, South Africa
- Authors: Fryer, Lindi
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2926 , vital:20343
- Description: The 2.65 to 2.05 Ga Transvaal Supergroup comprises one of the best-preserved and largely continuous successions in the world of Banded Iron-Formation (BIF), a chemical sedimentary rock composed of fine (mm to cm scale) interbanded iron-rich and iron-poor bands, developed atop the Archaean Kaapvaal Craton of southern Africa. The Transvaal BIF sequence contains at its upper stratigraphic part, an intriguing interlayered BIF-Mn association, namely the Hotazel Formation in the Kalahari Manganese Field, which constitutes the largest land-based manganese deposit on record. The genesis of the Hotazel deposits, and their exact significance in terms of atmosphere-hydrosphere-biosphere evolution, remain as elusive as they are challenging. In this thesis, an attempt is made to illuminate the origin and diagenesis of the Hotazel Formation and its post-depositional hydrothermal modification, through a highresolution geochemical study of the narrowest of the three BIF-Mn sedimentary cycles present in the Hotazel stratigraphy. This approach is coupled with a preliminary geochemical study of the distribution of Mn in older BIF of the Transvaal Supergroup as well (Kuruman and Griquatown Formations), so as to test recent models that causally link all BIFs in the Transvaal Supergroup under a common and evolving palaeo-environment of deposition. The results indicate that the cyclic deposition of the Hotazel BIF and enveloped Mn-rich sediments would have taken place in a stratified basin with a well-developed chemocline in terms of the vertical distributions of Mn and Fe, much like recent anoxic stratified basins such as the Orca Basin in the Gulf of Mexico. The increased Mn abundances as Mn-bearing ferrous carbonates in the upper part of the Griquatown BIF predating the Hotazel strata, also seems to lend support to the notion that the two BIFs are temporally interlinked as part of a broader sedimentary continuum. Finally, the largely conservative behaviour of Mn and associated elements during hydrothermal alteration of the Hotazel rocks is re-assessed, and renewed emphasis is placed on the possibility that brine metasomatism may have been a key factor in Mn redistribution and residual enrichment.
- Full Text:
- Authors: Fryer, Lindi
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2926 , vital:20343
- Description: The 2.65 to 2.05 Ga Transvaal Supergroup comprises one of the best-preserved and largely continuous successions in the world of Banded Iron-Formation (BIF), a chemical sedimentary rock composed of fine (mm to cm scale) interbanded iron-rich and iron-poor bands, developed atop the Archaean Kaapvaal Craton of southern Africa. The Transvaal BIF sequence contains at its upper stratigraphic part, an intriguing interlayered BIF-Mn association, namely the Hotazel Formation in the Kalahari Manganese Field, which constitutes the largest land-based manganese deposit on record. The genesis of the Hotazel deposits, and their exact significance in terms of atmosphere-hydrosphere-biosphere evolution, remain as elusive as they are challenging. In this thesis, an attempt is made to illuminate the origin and diagenesis of the Hotazel Formation and its post-depositional hydrothermal modification, through a highresolution geochemical study of the narrowest of the three BIF-Mn sedimentary cycles present in the Hotazel stratigraphy. This approach is coupled with a preliminary geochemical study of the distribution of Mn in older BIF of the Transvaal Supergroup as well (Kuruman and Griquatown Formations), so as to test recent models that causally link all BIFs in the Transvaal Supergroup under a common and evolving palaeo-environment of deposition. The results indicate that the cyclic deposition of the Hotazel BIF and enveloped Mn-rich sediments would have taken place in a stratified basin with a well-developed chemocline in terms of the vertical distributions of Mn and Fe, much like recent anoxic stratified basins such as the Orca Basin in the Gulf of Mexico. The increased Mn abundances as Mn-bearing ferrous carbonates in the upper part of the Griquatown BIF predating the Hotazel strata, also seems to lend support to the notion that the two BIFs are temporally interlinked as part of a broader sedimentary continuum. Finally, the largely conservative behaviour of Mn and associated elements during hydrothermal alteration of the Hotazel rocks is re-assessed, and renewed emphasis is placed on the possibility that brine metasomatism may have been a key factor in Mn redistribution and residual enrichment.
- Full Text:
Exploration, monetization, disillusion: a history of upstream oil development in the onshore Algoa basin
- Authors: James, Jonathan Scott
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3870 , vital:20551
- Description: The onshore Algoa basin has, since the mid-1960s, been an area of interest for oil and gas exploration. Despite the general lack of knowledge and publicly available information on the topic, a large amount of geological and geophysical data has been collected on the region owing to the oil and gas exploration. The intended aim of this thesis is to compile and construct a historical narrative of the oil and gas exploration that took place within the onshore Algoa basin, and to then contextualize that localized narrative within the greater macro-narrative of the global oil and gas industry. This thesis is primarily concerned with the time period beginning in the early 1960s up to mid-2014, however reference is also made to events pre-1960. For the purposes of compartmentalizing the various areas of research covered, the thesis has been divided into three broad areas of interest: the geology of the onshore Algoa basin, the global oil market and its impact on exploration therein, and the attempts to monetize the leases that came to be purchased post-exploration. The narrative on the geology of the onshore Algoa basin is aimed at providing a summarized account of the most important details pertaining to the search for petroleum systems in simplified, yet accurate, language. The aspects of the geology which command the most attention are those which are necessary in functioning petroleum systems such as suitable permeabilities, porosities, reservoir rocks, trapping mechanisms and cap rocks. The global oil and gas market is also used to contextualize the search for oil and gas within the onshore Algoa basin and is explained against the backdrop of the global oil trade and the sanctions imposed on the apartheid state. Furthermore, the analysis of the attempts to monetize leases within the onshore Algoa basin will provide a financial reference point to the shortcomings of the exploration and monetization efforts. The purpose of this thesis is to construct a historical narrative of the onshore Algoa basin which not only gives an accurate portrayal of the exploration efforts that have taken place thus far, but to also provide a enough detail of those exploration efforts to indicate the future of the onshore Algoa basin as an exploration play.
- Full Text:
- Authors: James, Jonathan Scott
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3870 , vital:20551
- Description: The onshore Algoa basin has, since the mid-1960s, been an area of interest for oil and gas exploration. Despite the general lack of knowledge and publicly available information on the topic, a large amount of geological and geophysical data has been collected on the region owing to the oil and gas exploration. The intended aim of this thesis is to compile and construct a historical narrative of the oil and gas exploration that took place within the onshore Algoa basin, and to then contextualize that localized narrative within the greater macro-narrative of the global oil and gas industry. This thesis is primarily concerned with the time period beginning in the early 1960s up to mid-2014, however reference is also made to events pre-1960. For the purposes of compartmentalizing the various areas of research covered, the thesis has been divided into three broad areas of interest: the geology of the onshore Algoa basin, the global oil market and its impact on exploration therein, and the attempts to monetize the leases that came to be purchased post-exploration. The narrative on the geology of the onshore Algoa basin is aimed at providing a summarized account of the most important details pertaining to the search for petroleum systems in simplified, yet accurate, language. The aspects of the geology which command the most attention are those which are necessary in functioning petroleum systems such as suitable permeabilities, porosities, reservoir rocks, trapping mechanisms and cap rocks. The global oil and gas market is also used to contextualize the search for oil and gas within the onshore Algoa basin and is explained against the backdrop of the global oil trade and the sanctions imposed on the apartheid state. Furthermore, the analysis of the attempts to monetize leases within the onshore Algoa basin will provide a financial reference point to the shortcomings of the exploration and monetization efforts. The purpose of this thesis is to construct a historical narrative of the onshore Algoa basin which not only gives an accurate portrayal of the exploration efforts that have taken place thus far, but to also provide a enough detail of those exploration efforts to indicate the future of the onshore Algoa basin as an exploration play.
- Full Text:
Environmental conflict resolution: a critical analysis of the role of interests and value
- Authors: Mweshi, John
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/55842 , vital:26740
- Description: This thesis intends to contribute to an enhanced understanding of environmental conflicts and their resolution. To accomplish this task the thesis will ascertain the role that value and interests play in environmental conflicts in order to establish an adequate basis upon which they can be resolved. In the process, the thesis will also examine three different approaches, namely, the Standard Approach; the Environmental Impact Assessment (EIA) framework; and the Structured Decision Making (SDM) approach. First, the standard approach is informed by the understanding that focusing on interests instead of human values makes the resolution of conflicts more tractable. In contrast, this thesis argues that an exclusive focus on interests, in the context of environmental conflict resolution, is inadequate in some important respects because there are other factors to be considered such as the environmental impacts at the root of the conflict. Second, the thesis examines the focus on impacts that characterises EIAs. It argues that this approach remedies the limitations of the standard approach insofar as impacts are understood in terms of object value. However, the EIA approach does not provide much guidance on how to deal with conflicting human values. Third, taking into account the fact that the standard approach does not address the question of object value, while the EIA addresses object value but does not deal directly with human values, the thesis examines the SDM approach to environmental risk decisions. The thesis argues that while the SDM approach claims to deal with conflicts involving human values head-on, it does not provide a viable alternative in terms of environmental conflict resolution. This is because it fails to recognise the key distinction between human values and object value despite acknowledging the presence of multiple value dimensions as a major obstacle to value trade-offs and therefore to the resolution of value conflicts. Finally, the thesis recommends an adequate basis upon which environmental conflicts can be resolved.
- Full Text:
- Authors: Mweshi, John
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/55842 , vital:26740
- Description: This thesis intends to contribute to an enhanced understanding of environmental conflicts and their resolution. To accomplish this task the thesis will ascertain the role that value and interests play in environmental conflicts in order to establish an adequate basis upon which they can be resolved. In the process, the thesis will also examine three different approaches, namely, the Standard Approach; the Environmental Impact Assessment (EIA) framework; and the Structured Decision Making (SDM) approach. First, the standard approach is informed by the understanding that focusing on interests instead of human values makes the resolution of conflicts more tractable. In contrast, this thesis argues that an exclusive focus on interests, in the context of environmental conflict resolution, is inadequate in some important respects because there are other factors to be considered such as the environmental impacts at the root of the conflict. Second, the thesis examines the focus on impacts that characterises EIAs. It argues that this approach remedies the limitations of the standard approach insofar as impacts are understood in terms of object value. However, the EIA approach does not provide much guidance on how to deal with conflicting human values. Third, taking into account the fact that the standard approach does not address the question of object value, while the EIA addresses object value but does not deal directly with human values, the thesis examines the SDM approach to environmental risk decisions. The thesis argues that while the SDM approach claims to deal with conflicts involving human values head-on, it does not provide a viable alternative in terms of environmental conflict resolution. This is because it fails to recognise the key distinction between human values and object value despite acknowledging the presence of multiple value dimensions as a major obstacle to value trade-offs and therefore to the resolution of value conflicts. Finally, the thesis recommends an adequate basis upon which environmental conflicts can be resolved.
- Full Text:
Spatio-temporal variation in the phytobenthos and phytoplankton community structure and composition of particulate matter along a river-estuary continuum assessed using microscopic and stable isotope analyses
- Authors: Dalu, Tatenda
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54416 , vital:26563
- Description: Phytoplankton and phytobenthos communities play an important role in lotic systems as primary producers providing essential biomolecules to higher trophic oganisms and are important indicators for environmental or ecological change. In this thesis, field studies (observational and experimental) along a river–estuary continuum were conducted to assess the spatio-temporal variation and development of phytobenthos and phytoplankton communities using a combination of stable isotope and community analyses in a temperate southern African system across four study periods: September (early spring) and November/December (late spring) 2012, and February (summer) and May/June (winter) 2013. Additionally, the sources and composition of the particulate organic matter were also analysed using stable isotope (δ15N and δ13C) analysis. The effects of substrate type and flood occurrence were assessed through experimental studies at an up- and downstream site of the river after a major flood event that occurred between October and November 2012. Common household tiles were used as artificial substrates to study the development/succession of phytobenthos communities after the flood disturbance. Distinct diatom communities were observed between upstream and downstream sites and at each site, community structure changed with time indicating succession. In addition to recording diatom characteristics on three natural substrates, namely; macrophytes, rocks and sediment, artificial substrates observations were also made on three different types of artificial substrates, namely; brick, brown clay and grey clay tiles. The natural (species richness 78) and artificial substrates (sp. richness 93) had different communities with the latter having greater species richness. Common phytobenthos taxa were not restricted to a single substrate but preference was generally high for the artificial substrates, especially brown tiles (mean sp. richness 47). Results of the redundancy analysis (RDA) analysis indicated that ammonium, conductivity, total dissolved solids, salinity, pH, oxygen reduction potential, phosphate and water depth were the major determinants of the phytobenthos composition at the two sites. The spatio–temporal variation of phytoplankton and phytobenthos communities and allochthonous organic matter along the river–estuary continuum was assessed at 8 sites using a combination of community and stable isotope analyses. A total of 178 species belonging to 78 genera were recorded with diatoms being predominant, accounting for 81.9 % of the total abundance. The total chl-a concentration along the river-estuary continuum increased from spring to a high in summer before decreasing to a low in winter. Periphyton communities were observed to be significantly different across sites (p < 0.05) in terms of species richness, abundances and isotopically The high periphytic δ15N values (range 7.9–15.2 ‰) recorded at the downstream sites compared to the pristine upstream sites (δ15N values range 4–7 ‰) suggest nutrient enrichment most likely derived from anthropogenic sources. Overall, our results reveal general patterns of periphyton communities and stable isotopes and provide improved information in the use of periphyton δ15N as an excellent indicator of anthropogenic nitrogen pollution. Ecologists are interested in the factors that control, and the variability in, the contributions of different sources to mixed organic materials traveling through lotic systems. We hypothesized that the source matter fuelling mixed organic pools in a river-estuary continuum varies over space and time, with the upper reaches of a system characterized by allochthonous-dominated material and autochthonous contributions becoming more important in the lower reaches. Samples of the mixed organic pools and allochthonous and autochthonous source materials were collected during the four study periods. The C:N ratios of suspended particulate matter (SPM) collected during summer and winter indicated that the lower reaches of the system had similar organic matter contributions from the freshwater and terrestrial sources. Stable isotope analysis in R revealed that the contributions of autochthonous organic matter were high in SPM along the entire continuum, and aquatic macrophytes were significant contributors to SPM specifically in the upper reaches. The terrestrial leaves made major contributions to the SPM in the middle regions of the system (i.e. downstream sites of the river, particularly in early and late spring). Bulk detritus had large allochthonous matter components in the lower reaches (estuary), and the contributions of aquatic macrophytes and benthic algae to bulk detritus were high (> 50 %) in the upper to middle reaches (river), but low (< 20 %) in the lower reaches (estuary). The current investigation represents the first attempt to assess the validity of the River Continuum Concept (RCC) in a southern African temperate river. The phytoplankton and phytobenthos communities, and chl-a concentration followed a trend similar to that proposed for the river continuum concept (RCC). The middle reaches based on the phytobenthos or phytoplankton communities and chl-a concentrations which were employed as proxies for primary production, were the most productive, while the upper reaches were the least primary productive. The evaluation of organic matter contributions to the SPM and detritus along the river–estuary continuum provided a baseline assessment of the nature and sources of potential food for consumers inhabiting different locations during different times of the year. Incorporating such spatio-temporal variations in SPM and detritus into food web studies will improve our understanding of the flow of carbon through aquatic systems.
- Full Text:
- Authors: Dalu, Tatenda
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54416 , vital:26563
- Description: Phytoplankton and phytobenthos communities play an important role in lotic systems as primary producers providing essential biomolecules to higher trophic oganisms and are important indicators for environmental or ecological change. In this thesis, field studies (observational and experimental) along a river–estuary continuum were conducted to assess the spatio-temporal variation and development of phytobenthos and phytoplankton communities using a combination of stable isotope and community analyses in a temperate southern African system across four study periods: September (early spring) and November/December (late spring) 2012, and February (summer) and May/June (winter) 2013. Additionally, the sources and composition of the particulate organic matter were also analysed using stable isotope (δ15N and δ13C) analysis. The effects of substrate type and flood occurrence were assessed through experimental studies at an up- and downstream site of the river after a major flood event that occurred between October and November 2012. Common household tiles were used as artificial substrates to study the development/succession of phytobenthos communities after the flood disturbance. Distinct diatom communities were observed between upstream and downstream sites and at each site, community structure changed with time indicating succession. In addition to recording diatom characteristics on three natural substrates, namely; macrophytes, rocks and sediment, artificial substrates observations were also made on three different types of artificial substrates, namely; brick, brown clay and grey clay tiles. The natural (species richness 78) and artificial substrates (sp. richness 93) had different communities with the latter having greater species richness. Common phytobenthos taxa were not restricted to a single substrate but preference was generally high for the artificial substrates, especially brown tiles (mean sp. richness 47). Results of the redundancy analysis (RDA) analysis indicated that ammonium, conductivity, total dissolved solids, salinity, pH, oxygen reduction potential, phosphate and water depth were the major determinants of the phytobenthos composition at the two sites. The spatio–temporal variation of phytoplankton and phytobenthos communities and allochthonous organic matter along the river–estuary continuum was assessed at 8 sites using a combination of community and stable isotope analyses. A total of 178 species belonging to 78 genera were recorded with diatoms being predominant, accounting for 81.9 % of the total abundance. The total chl-a concentration along the river-estuary continuum increased from spring to a high in summer before decreasing to a low in winter. Periphyton communities were observed to be significantly different across sites (p < 0.05) in terms of species richness, abundances and isotopically The high periphytic δ15N values (range 7.9–15.2 ‰) recorded at the downstream sites compared to the pristine upstream sites (δ15N values range 4–7 ‰) suggest nutrient enrichment most likely derived from anthropogenic sources. Overall, our results reveal general patterns of periphyton communities and stable isotopes and provide improved information in the use of periphyton δ15N as an excellent indicator of anthropogenic nitrogen pollution. Ecologists are interested in the factors that control, and the variability in, the contributions of different sources to mixed organic materials traveling through lotic systems. We hypothesized that the source matter fuelling mixed organic pools in a river-estuary continuum varies over space and time, with the upper reaches of a system characterized by allochthonous-dominated material and autochthonous contributions becoming more important in the lower reaches. Samples of the mixed organic pools and allochthonous and autochthonous source materials were collected during the four study periods. The C:N ratios of suspended particulate matter (SPM) collected during summer and winter indicated that the lower reaches of the system had similar organic matter contributions from the freshwater and terrestrial sources. Stable isotope analysis in R revealed that the contributions of autochthonous organic matter were high in SPM along the entire continuum, and aquatic macrophytes were significant contributors to SPM specifically in the upper reaches. The terrestrial leaves made major contributions to the SPM in the middle regions of the system (i.e. downstream sites of the river, particularly in early and late spring). Bulk detritus had large allochthonous matter components in the lower reaches (estuary), and the contributions of aquatic macrophytes and benthic algae to bulk detritus were high (> 50 %) in the upper to middle reaches (river), but low (< 20 %) in the lower reaches (estuary). The current investigation represents the first attempt to assess the validity of the River Continuum Concept (RCC) in a southern African temperate river. The phytoplankton and phytobenthos communities, and chl-a concentration followed a trend similar to that proposed for the river continuum concept (RCC). The middle reaches based on the phytobenthos or phytoplankton communities and chl-a concentrations which were employed as proxies for primary production, were the most productive, while the upper reaches were the least primary productive. The evaluation of organic matter contributions to the SPM and detritus along the river–estuary continuum provided a baseline assessment of the nature and sources of potential food for consumers inhabiting different locations during different times of the year. Incorporating such spatio-temporal variations in SPM and detritus into food web studies will improve our understanding of the flow of carbon through aquatic systems.
- Full Text:
Structural studies on yeast eIF5A using biomolecular NMR and molecular dynamics
- Authors: Sigauke, Lester Takunda
- Date: 2015
- Subjects: Molecular dynamics , Reverse transcriptase , HIV (Viruses) , HIV infections , Eukaryotic cells , Yeast
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4547 , http://hdl.handle.net/10962/d1017927
- Description: Eukaryotic initiation factor 5A, eIF5A, is a ubiquitous eukaryotic protein that has been shown to influence the translation initiation of a specific subset of mRNAs. It is the only protein known to undergo hypusination in a two-step post translational modification process involving deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH) enzymes. Hypusination has been shown to influence translation of HIV-1 and HTLV-1 nuclear export signals, while the involvement of active hypusinated eIF5A in induction of IRES mediated processes that initiate pro-apoptotic process have inspired studies into the manipulation of eIF5A in anti-cancer and anti-diabetic therapies. eIF5A oligomerisation in eukaryotic systems has been shown to be influenced by hypusination and the mechanism of dimerisation is RNA dependent. Nuclear magnetic resonance spectroscopy approaches were proposed to solve the structure of the hypusinated eIF5A in solution in order to understand the influence of hypusination on the monomeric arrangement which enhances dimerisation and activates the protein. Cleavage of the 18 kDa protein monomer by introduction of thrombin cleavage site within the flexible domain was thought to give rise to 10 kDa fragments accessible to a 600 MHz NMR spectrometer. Heteronuclear single quantum correlation experiments of the mutated isotopically labelled protein expressed in E. coli showed that the eIF5A protein with a thrombin cleavage insert, eIF5AThr (eIF5A subscript Thr), was unfolded. In silico investigations of the behaviour of eIF5A and eIF5AThr (eIF5A subscript Thr) models in solution using molecular dynamics showed that the mutated model had different solution dynamics to the native model. Chemical shift predictors were used to extract atomic resolution data of solution dynamics and the introduction of rigidity in the flexible loop region of eIF5A affected solution behaviour consistent with lack of in vivo function of eIF5AThr (eIF5A subscript Thr) in yeast. Residual dipolar coupling and T₁ relaxation times were calculated in anticipation of the extraction of experimental data from RDC and relaxation dispersion experiments based on HSQC measurable restraints.
- Full Text:
- Authors: Sigauke, Lester Takunda
- Date: 2015
- Subjects: Molecular dynamics , Reverse transcriptase , HIV (Viruses) , HIV infections , Eukaryotic cells , Yeast
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4547 , http://hdl.handle.net/10962/d1017927
- Description: Eukaryotic initiation factor 5A, eIF5A, is a ubiquitous eukaryotic protein that has been shown to influence the translation initiation of a specific subset of mRNAs. It is the only protein known to undergo hypusination in a two-step post translational modification process involving deoxyhypusine synthase (DHS) and deoxyhypusine hydroxylase (DOHH) enzymes. Hypusination has been shown to influence translation of HIV-1 and HTLV-1 nuclear export signals, while the involvement of active hypusinated eIF5A in induction of IRES mediated processes that initiate pro-apoptotic process have inspired studies into the manipulation of eIF5A in anti-cancer and anti-diabetic therapies. eIF5A oligomerisation in eukaryotic systems has been shown to be influenced by hypusination and the mechanism of dimerisation is RNA dependent. Nuclear magnetic resonance spectroscopy approaches were proposed to solve the structure of the hypusinated eIF5A in solution in order to understand the influence of hypusination on the monomeric arrangement which enhances dimerisation and activates the protein. Cleavage of the 18 kDa protein monomer by introduction of thrombin cleavage site within the flexible domain was thought to give rise to 10 kDa fragments accessible to a 600 MHz NMR spectrometer. Heteronuclear single quantum correlation experiments of the mutated isotopically labelled protein expressed in E. coli showed that the eIF5A protein with a thrombin cleavage insert, eIF5AThr (eIF5A subscript Thr), was unfolded. In silico investigations of the behaviour of eIF5A and eIF5AThr (eIF5A subscript Thr) models in solution using molecular dynamics showed that the mutated model had different solution dynamics to the native model. Chemical shift predictors were used to extract atomic resolution data of solution dynamics and the introduction of rigidity in the flexible loop region of eIF5A affected solution behaviour consistent with lack of in vivo function of eIF5AThr (eIF5A subscript Thr) in yeast. Residual dipolar coupling and T₁ relaxation times were calculated in anticipation of the extraction of experimental data from RDC and relaxation dispersion experiments based on HSQC measurable restraints.
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The interrelationships between foreign direct investment and economic growth in Africa
- Authors: Bolani, Lindelwa Mandisa
- Date: 2015
- Subjects: Investments, Foreign -- Africa , Economic development -- Africa , Africa -- Economic conditions -- 1960- , Africa -- Foreign economic relations , Gross domestic product -- Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1123 , http://hdl.handle.net/10962/d1019885
- Description: There has been a long search for the keys to development and economic growth in Africa. This study investigates the relationship between FDI and economic growth over the period 2000-2012 using data from 48 African countries. On the aggregate regional level FDI and economic growth were found to be positively correlated during this period. Using panel data econometric techniques and the Panel Granger Causality test, results revealed that a bi-directional causality relationship existed between FDI and GDP. Thus, the results suggest that GDP is a requirement for increased investment, and at the same time is the result of increased foreign investment. Thus, the conclusion is that African policy makers are justified in increasing their attempts to create an attractive business environment for foreign investors, as it is beneficial for economic growth.
- Full Text:
- Authors: Bolani, Lindelwa Mandisa
- Date: 2015
- Subjects: Investments, Foreign -- Africa , Economic development -- Africa , Africa -- Economic conditions -- 1960- , Africa -- Foreign economic relations , Gross domestic product -- Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1123 , http://hdl.handle.net/10962/d1019885
- Description: There has been a long search for the keys to development and economic growth in Africa. This study investigates the relationship between FDI and economic growth over the period 2000-2012 using data from 48 African countries. On the aggregate regional level FDI and economic growth were found to be positively correlated during this period. Using panel data econometric techniques and the Panel Granger Causality test, results revealed that a bi-directional causality relationship existed between FDI and GDP. Thus, the results suggest that GDP is a requirement for increased investment, and at the same time is the result of increased foreign investment. Thus, the conclusion is that African policy makers are justified in increasing their attempts to create an attractive business environment for foreign investors, as it is beneficial for economic growth.
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An assessment of equilibrium in the Merensky Reef : a textural, geochemical and Nd isotope study of coexisting plagioclase and orthopyroxene from Winnaarshoek in the eastern Bushveld Complex, RSA
- Authors: Raines, Mark Douglas
- Date: 2014
- Subjects: Mines and mineral resources -- South Africa -- Bushveld Complex , Plagioclase , Neodymium , Petrology , Electron probe microanalysis , Isotope geology , Mineralogical chemistry , Crystallization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5079 , http://hdl.handle.net/10962/d1015644
- Description: Evidence of mineral disequilibrium is presented for the Merensky Reef at Winnaarshoek in the eastern Bushveld Complex. Petrographic disequilibrium textures, disequilibrium in orthopyroxene, plagioclase and clinopyroxene mineral compositions as well as disequilibrium in Sm-Nd isotopic compositions of whole rock samples and coexisting plagioclase and orthopyroxene are presented. Disequilibrium textures presented include clinopyroxene exsolution lamellae in orthopyroxene; resorbed plagioclase in orthopyroxene or relict plagioclase; various inclusions such as orthopyroxene, plagioclase or clinopyroxene in larger oikocrysts of clinopyroxene or orthopyroxene; discontinuous rims of clinopyroxene surrounding orthopyroxene; resorbed orthopyroxene in clinopyroxene; and corona textures associated with olivine. These textures were used to derive a possible mineral crystallization sequence. At least two sequences of crystallization took place, both of which crystallized plagioclase first. One sequence then crystallized olivine which was then consumed to produce orthopyroxene which crystallized prior to late clinopyroxene. The other sequence indicates orthopyroxene crystallization after plagioclase crystallization, followed by crystallization of clinopyroxene. These sequences indicate at least two magmas were responsible for the genesis of the Merensky Reef and its hanging wall and footwall units. Compositionally, disequilibrium is evident in the range of compositions found in coexisting orthopyroxene, plagioclase and clinopyroxene with stratigraphic height, with particular reference to the change in mineral composition in each of the hanging wall, Reef and footwall units. Orthopyroxene compositions range in Mg numbers between 74.6 and 82.9 (77.4) in the hanging wall, 78.5 and 87.0 (avg. 81.1) in the Reef, and 77.9 and 84.1 (avg. 81.3) in the footwall. Plagioclase compositions range in An content between An64.9 and An82.3 (avg. An75.1) in the hanging wall, An56.8 to An70.8 (avg. An62.7) in the Reef, and An54.2 to An86.3 (avg. An73.2) in the footwall. In terms of Sm-Nd isotopic compositions, disequilibrium is evident between both whole rock samples and coexisting plagioclase and orthopyroxenes. Bulk rock Sm-Nd isotopic compositions show a range in ԐNd values between ԐNd (2.06 Ga) = -4.8 to -6.4 in the hangingwall, ԐNd (2.06 Ga) = -6.3 to -8.5 in the Reef, and ԐNd (2.06 Ga) = -4.5 to -6.3 in the footwall. Similar ԐNd values are present in the hanging wall and footwall units, with a clear “spike” in the Merensky Reef. ԐNd values in plagioclase are between ԐNd (2.06 Ga) = -5.8 and -7.8, while orthopyroxene isotopic Sm-Nd values are between ԐNd (2.06 Ga = -7.1 and -9.1. The mineral disequilibrium features presented within this study help elucidate the crystallization sequence of the magma as well as to constrain the contamination of the magma upon ascension and emplacement of the Merensky Reef. The results of this study favour a model where a mantle plume resulted in the ascent of a new magma which was contaminated by the assimilation of old, lower crust. Contamination took place prior to the possible lateral emplacement of the Merensky reef as a density current. 5-10% contamination of depleted mantle or a B2-“like” source by Archaean TTGs is modeled to achieve the contamination “spike” of ԐNd = -8.5 in the Merensky Reef.
- Full Text:
- Authors: Raines, Mark Douglas
- Date: 2014
- Subjects: Mines and mineral resources -- South Africa -- Bushveld Complex , Plagioclase , Neodymium , Petrology , Electron probe microanalysis , Isotope geology , Mineralogical chemistry , Crystallization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5079 , http://hdl.handle.net/10962/d1015644
- Description: Evidence of mineral disequilibrium is presented for the Merensky Reef at Winnaarshoek in the eastern Bushveld Complex. Petrographic disequilibrium textures, disequilibrium in orthopyroxene, plagioclase and clinopyroxene mineral compositions as well as disequilibrium in Sm-Nd isotopic compositions of whole rock samples and coexisting plagioclase and orthopyroxene are presented. Disequilibrium textures presented include clinopyroxene exsolution lamellae in orthopyroxene; resorbed plagioclase in orthopyroxene or relict plagioclase; various inclusions such as orthopyroxene, plagioclase or clinopyroxene in larger oikocrysts of clinopyroxene or orthopyroxene; discontinuous rims of clinopyroxene surrounding orthopyroxene; resorbed orthopyroxene in clinopyroxene; and corona textures associated with olivine. These textures were used to derive a possible mineral crystallization sequence. At least two sequences of crystallization took place, both of which crystallized plagioclase first. One sequence then crystallized olivine which was then consumed to produce orthopyroxene which crystallized prior to late clinopyroxene. The other sequence indicates orthopyroxene crystallization after plagioclase crystallization, followed by crystallization of clinopyroxene. These sequences indicate at least two magmas were responsible for the genesis of the Merensky Reef and its hanging wall and footwall units. Compositionally, disequilibrium is evident in the range of compositions found in coexisting orthopyroxene, plagioclase and clinopyroxene with stratigraphic height, with particular reference to the change in mineral composition in each of the hanging wall, Reef and footwall units. Orthopyroxene compositions range in Mg numbers between 74.6 and 82.9 (77.4) in the hanging wall, 78.5 and 87.0 (avg. 81.1) in the Reef, and 77.9 and 84.1 (avg. 81.3) in the footwall. Plagioclase compositions range in An content between An64.9 and An82.3 (avg. An75.1) in the hanging wall, An56.8 to An70.8 (avg. An62.7) in the Reef, and An54.2 to An86.3 (avg. An73.2) in the footwall. In terms of Sm-Nd isotopic compositions, disequilibrium is evident between both whole rock samples and coexisting plagioclase and orthopyroxenes. Bulk rock Sm-Nd isotopic compositions show a range in ԐNd values between ԐNd (2.06 Ga) = -4.8 to -6.4 in the hangingwall, ԐNd (2.06 Ga) = -6.3 to -8.5 in the Reef, and ԐNd (2.06 Ga) = -4.5 to -6.3 in the footwall. Similar ԐNd values are present in the hanging wall and footwall units, with a clear “spike” in the Merensky Reef. ԐNd values in plagioclase are between ԐNd (2.06 Ga) = -5.8 and -7.8, while orthopyroxene isotopic Sm-Nd values are between ԐNd (2.06 Ga = -7.1 and -9.1. The mineral disequilibrium features presented within this study help elucidate the crystallization sequence of the magma as well as to constrain the contamination of the magma upon ascension and emplacement of the Merensky Reef. The results of this study favour a model where a mantle plume resulted in the ascent of a new magma which was contaminated by the assimilation of old, lower crust. Contamination took place prior to the possible lateral emplacement of the Merensky reef as a density current. 5-10% contamination of depleted mantle or a B2-“like” source by Archaean TTGs is modeled to achieve the contamination “spike” of ԐNd = -8.5 in the Merensky Reef.
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The implications of rural-urban migration on employment and household income with particular reference to Lesotho
- Authors: Damane, Moeti
- Date: 2012
- Subjects: Rural-urban migration -- Employment -- Lesotho Informal sector (Economics) -- Lesotho Lesotho -- Economic conditions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1002 , http://hdl.handle.net/10962/d1002737
- Description: The research investigates the impact of internal rural - urban migration III Lesotho on household income and employment. Using data gathered from the 2002/03 household survey, the 2006 nationwide census and a questionnaire on rural - urban migration in Lesotho administered to 500 respondents in Maseru and Leribe, we estimate a logit model of the probability of employment in Lesotho in 2008 given a set of independent variables. The independent variables are respondent's work experience; years of education completed; employment status in 2004; employment status in 2008; gender; job skill level; place of residence in 2004 and a categorical variable that measures whether or not the respondent is a rural - urban migrant. The results suggest that migration and work experience have no significant impact on an individual's likelihood of being employed in the country's formal sector. Also, it was found that the higher the level of education an individual has, the less likely are their chances of employment in the country's formal sector because of the lack of formal jobs in the urban areas. Over 50% of Lesotho's workforce employed in the urban areas was discovered to work in the informal sector. The study concludes that there is a lack of jobs in Lesotho's urban formal sector that results in a thriving informal sector. The advantages of informal sector jobs to the rural - urban migrant include an increase in their standard of living as well as that of their family members left behind in the rural areas but the disadvantages include low levels of investor confidence that lead to a decrease in overall economic development and growth in the country.
- Full Text:
- Authors: Damane, Moeti
- Date: 2012
- Subjects: Rural-urban migration -- Employment -- Lesotho Informal sector (Economics) -- Lesotho Lesotho -- Economic conditions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1002 , http://hdl.handle.net/10962/d1002737
- Description: The research investigates the impact of internal rural - urban migration III Lesotho on household income and employment. Using data gathered from the 2002/03 household survey, the 2006 nationwide census and a questionnaire on rural - urban migration in Lesotho administered to 500 respondents in Maseru and Leribe, we estimate a logit model of the probability of employment in Lesotho in 2008 given a set of independent variables. The independent variables are respondent's work experience; years of education completed; employment status in 2004; employment status in 2008; gender; job skill level; place of residence in 2004 and a categorical variable that measures whether or not the respondent is a rural - urban migrant. The results suggest that migration and work experience have no significant impact on an individual's likelihood of being employed in the country's formal sector. Also, it was found that the higher the level of education an individual has, the less likely are their chances of employment in the country's formal sector because of the lack of formal jobs in the urban areas. Over 50% of Lesotho's workforce employed in the urban areas was discovered to work in the informal sector. The study concludes that there is a lack of jobs in Lesotho's urban formal sector that results in a thriving informal sector. The advantages of informal sector jobs to the rural - urban migrant include an increase in their standard of living as well as that of their family members left behind in the rural areas but the disadvantages include low levels of investor confidence that lead to a decrease in overall economic development and growth in the country.
- Full Text:
The development and technologizing of selected Sepedi ICT terminology
- Authors: Magagane, Raesetja Linah
- Date: 2011
- Subjects: Northern Sotho language -- Terms and phrases Northern Sotho language -- Terminology Northern Sotho language -- Computer-assisted instruction Communication -- Technological innovations
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3581 , http://hdl.handle.net/10962/d1002156
- Description: It is my wish that the Sepedi language speakers, through the development and technologization of certain Sepedi ICT terminology, are able to operate a computer in their own language, and implement the new developed and technologized ICT terminology (technologization). The pupils and students at their various institutions should be made comfortable in using the developed and technologized Sepedi language terminology. In the long run the Sepedi language speakers should be ensured access to the web in order to find information about Sepedi language, culture and terms in disciplines such as ICT. It is recommended in this thesis that higher learning institutions offer bursaries to students to develop all South African languages in such a manner that they can be used in all high status functions.
- Full Text:
- Authors: Magagane, Raesetja Linah
- Date: 2011
- Subjects: Northern Sotho language -- Terms and phrases Northern Sotho language -- Terminology Northern Sotho language -- Computer-assisted instruction Communication -- Technological innovations
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3581 , http://hdl.handle.net/10962/d1002156
- Description: It is my wish that the Sepedi language speakers, through the development and technologization of certain Sepedi ICT terminology, are able to operate a computer in their own language, and implement the new developed and technologized ICT terminology (technologization). The pupils and students at their various institutions should be made comfortable in using the developed and technologized Sepedi language terminology. In the long run the Sepedi language speakers should be ensured access to the web in order to find information about Sepedi language, culture and terms in disciplines such as ICT. It is recommended in this thesis that higher learning institutions offer bursaries to students to develop all South African languages in such a manner that they can be used in all high status functions.
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The role of the ward committees as an interface between local government and community: a case study of Makana Municipality
- Authors: Stuurman, Sonwabo Happyboy
- Date: 2009
- Subjects: Makana Municipality Local government -- South Africa -- Case studies Local government -- South Africa -- Citizen participation Community development -- South Africa -- Case studies Political participation -- South Africa -- Case studies Democracy -- South Africa South Africa -- Politics and government -- 1994- South Africa -- Politics and government -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3292 , http://hdl.handle.net/10962/d1003080
- Description: The Ward Committee System was introduced in South Africa in 2001 as a tool to bring government closer to the people and to enhance participatory democracy. The Makana Municipality adopted the system in 2002. Previous research on local government indicates that these structures have not been effective due to the lack of resources to sustain them. This study was interested in furthering such research, using the Makana Municipality as a case study during which unstructured, in-depth interviews and focus group discussions were conducted with Ward Councillors, Ward Committee Members and Grade 12 learners. The aim of the research was to investigate whether the ward committees did indeed promote the notion of participatory democracy and to what extent grass roots development has been enhanced by this structure of local government. The findings from both the respondents and the observations indicate that, in addition to the lack of resources, the underutilization of the Ward Committee System is a result of the effect of opposing political affiliations within the ward committee system, affiliations that undermine the goal of collaborative decision-making. Whereas the ward committee system is a positive idea, the findings suggest that the government is not supporting these structures by failing to equip the ward committee members with necessary capacities and skills. Therefore, if municipalities are committed to bridging the gap between local government and the community, and are keen to enhance participatory democracy, then capacity building of the ward committees and respect for their role during the decision-making process need to be taken seriously. At present, ward committee members are not influential and active in the decision-making process. In addition, the youth as prospective future ward committee members seemed disillusioned with the notion of participatory democracy, and instead have adopted the mentality that nepotism and corruption, as displayed by those in power, is the only way of governance. This research suggests that the ward committee system, intended to bring government closer to the people, may in fact not only alienate government from the people, but also the people from each other.
- Full Text:
- Authors: Stuurman, Sonwabo Happyboy
- Date: 2009
- Subjects: Makana Municipality Local government -- South Africa -- Case studies Local government -- South Africa -- Citizen participation Community development -- South Africa -- Case studies Political participation -- South Africa -- Case studies Democracy -- South Africa South Africa -- Politics and government -- 1994- South Africa -- Politics and government -- 21st century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3292 , http://hdl.handle.net/10962/d1003080
- Description: The Ward Committee System was introduced in South Africa in 2001 as a tool to bring government closer to the people and to enhance participatory democracy. The Makana Municipality adopted the system in 2002. Previous research on local government indicates that these structures have not been effective due to the lack of resources to sustain them. This study was interested in furthering such research, using the Makana Municipality as a case study during which unstructured, in-depth interviews and focus group discussions were conducted with Ward Councillors, Ward Committee Members and Grade 12 learners. The aim of the research was to investigate whether the ward committees did indeed promote the notion of participatory democracy and to what extent grass roots development has been enhanced by this structure of local government. The findings from both the respondents and the observations indicate that, in addition to the lack of resources, the underutilization of the Ward Committee System is a result of the effect of opposing political affiliations within the ward committee system, affiliations that undermine the goal of collaborative decision-making. Whereas the ward committee system is a positive idea, the findings suggest that the government is not supporting these structures by failing to equip the ward committee members with necessary capacities and skills. Therefore, if municipalities are committed to bridging the gap between local government and the community, and are keen to enhance participatory democracy, then capacity building of the ward committees and respect for their role during the decision-making process need to be taken seriously. At present, ward committee members are not influential and active in the decision-making process. In addition, the youth as prospective future ward committee members seemed disillusioned with the notion of participatory democracy, and instead have adopted the mentality that nepotism and corruption, as displayed by those in power, is the only way of governance. This research suggests that the ward committee system, intended to bring government closer to the people, may in fact not only alienate government from the people, but also the people from each other.
- Full Text:
Interest rate risk management : a case study of GBS Mutual Bank
- Authors: Williamson, Gareth Alan
- Date: 2008
- Subjects: GBS Mutual Bank , Interest rates -- Case studies , Interest rate risk -- Case studies , Risk management -- Case studies , Financial risk -- Case studies , Banks and banking -- Case studies
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:986 , http://hdl.handle.net/10962/d1002720 , GBS Mutual Bank , Interest rates -- Case studies , Interest rate risk -- Case studies , Risk management -- Case studies , Financial risk -- Case studies , Banks and banking -- Case studies
- Description: Banks play a pivotal role in the economic growth and development of countries, primarily through the diversification of risk for both themselves and other economic agents. Interest rate risk is regarded as one of the most prominent financial risks faced by a bank. A large portion of private banks’ revenue stems from net interest income that is generated from the difference between various assets and liabilities that are held on the balance sheet. Fluctuations in the interest rate can alter a bank’s interest income and value, making interest rate risk management vital to its success. The asset and liability committee of a bank is the internal committee charged with the duty of managing the bank’s interest rate risk exposure through the use of various hedging strategies and instruments. This thesis uses a case study methodology to analyse GBS Mutual Bank interest rate risk management. Its specific business circumstances, balance sheet structure and the market conditions over a specified period are used to comment on the practicality of a variety of balance sheet positioning strategies and derivative hedging instruments. The thesis also provides recommendations for the bank’s asset and liability committee in terms of its functions and organisation. It is elucidated that the most practical balance sheet hedging strategies are a volume strategy and immunisation, while the most practical derivative hedging instruments are interest rate futures and interest rate collars. It is found that the bank has a well functioning asset and liability committee whose only encumbrance to its functionality is the inadequacy of the informational technology used to measure, control and manage its interest rate risk position. This thesis concludes by summarising the practicality of the various interest rate risk hedging alternatives available to the GBS Mutual Bank. Implementing a particular strategy or instrument depends, of course, on its asset and liability committee’s decision.
- Full Text:
- Authors: Williamson, Gareth Alan
- Date: 2008
- Subjects: GBS Mutual Bank , Interest rates -- Case studies , Interest rate risk -- Case studies , Risk management -- Case studies , Financial risk -- Case studies , Banks and banking -- Case studies
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:986 , http://hdl.handle.net/10962/d1002720 , GBS Mutual Bank , Interest rates -- Case studies , Interest rate risk -- Case studies , Risk management -- Case studies , Financial risk -- Case studies , Banks and banking -- Case studies
- Description: Banks play a pivotal role in the economic growth and development of countries, primarily through the diversification of risk for both themselves and other economic agents. Interest rate risk is regarded as one of the most prominent financial risks faced by a bank. A large portion of private banks’ revenue stems from net interest income that is generated from the difference between various assets and liabilities that are held on the balance sheet. Fluctuations in the interest rate can alter a bank’s interest income and value, making interest rate risk management vital to its success. The asset and liability committee of a bank is the internal committee charged with the duty of managing the bank’s interest rate risk exposure through the use of various hedging strategies and instruments. This thesis uses a case study methodology to analyse GBS Mutual Bank interest rate risk management. Its specific business circumstances, balance sheet structure and the market conditions over a specified period are used to comment on the practicality of a variety of balance sheet positioning strategies and derivative hedging instruments. The thesis also provides recommendations for the bank’s asset and liability committee in terms of its functions and organisation. It is elucidated that the most practical balance sheet hedging strategies are a volume strategy and immunisation, while the most practical derivative hedging instruments are interest rate futures and interest rate collars. It is found that the bank has a well functioning asset and liability committee whose only encumbrance to its functionality is the inadequacy of the informational technology used to measure, control and manage its interest rate risk position. This thesis concludes by summarising the practicality of the various interest rate risk hedging alternatives available to the GBS Mutual Bank. Implementing a particular strategy or instrument depends, of course, on its asset and liability committee’s decision.
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Perceptions of the gap between theory and practice in the preparation of English language teachers at the Lesotho College of Education
- Authors: Molete, Bakae
- Date: 2008
- Subjects: Lesotho College of Education Education -- Research -- Lesotho Teachers -- Training of -- Lesotho Student teaching -- Lesotho English language -- Study and teaching -- Lesotho Observation (Educational method) English teachers -- Training of -- Lesotho
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1936 , http://hdl.handle.net/10962/d1007682
- Description: The distinction between theory and practice can be traced back to Aristotle (384-322 B.C). Theory has been seen as the preserve of the academician who, through research, produces knowledge for the practitioner to use in his/her practice. This research sets out to investigate perceptions of the respondents with regard to the extent to which theory is applicable in practice. It does this in the context of teacher training at the Lesotho College of Education, (LCE), a teacher training college in Lesotho. In this research project; a case study of 5 students from the LCE who had been on teaching practice, their mentor teachers on teaching practice, and a college lecturer who had observed said students on teaching practice was used. Data was collected by means of focus group interviews and semi-structured interviews. Relevant documents in the form of classroom observation forms were also used. The findings from the data analysis revealed that students on teaching practice had, to a great extent, had difficulties in applying what they had learned at the college when they got to teaching practice. Difficulties were mainly experienced in the areas of classroom and time management as well as in the application of the teaching methods learned at the college. This research takes a closer look at these difficulties. It investigates their probable causes and, finally, suggests ways of responding to them.
- Full Text:
- Authors: Molete, Bakae
- Date: 2008
- Subjects: Lesotho College of Education Education -- Research -- Lesotho Teachers -- Training of -- Lesotho Student teaching -- Lesotho English language -- Study and teaching -- Lesotho Observation (Educational method) English teachers -- Training of -- Lesotho
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1936 , http://hdl.handle.net/10962/d1007682
- Description: The distinction between theory and practice can be traced back to Aristotle (384-322 B.C). Theory has been seen as the preserve of the academician who, through research, produces knowledge for the practitioner to use in his/her practice. This research sets out to investigate perceptions of the respondents with regard to the extent to which theory is applicable in practice. It does this in the context of teacher training at the Lesotho College of Education, (LCE), a teacher training college in Lesotho. In this research project; a case study of 5 students from the LCE who had been on teaching practice, their mentor teachers on teaching practice, and a college lecturer who had observed said students on teaching practice was used. Data was collected by means of focus group interviews and semi-structured interviews. Relevant documents in the form of classroom observation forms were also used. The findings from the data analysis revealed that students on teaching practice had, to a great extent, had difficulties in applying what they had learned at the college when they got to teaching practice. Difficulties were mainly experienced in the areas of classroom and time management as well as in the application of the teaching methods learned at the college. This research takes a closer look at these difficulties. It investigates their probable causes and, finally, suggests ways of responding to them.
- Full Text:
Social learning processes in a citrus farming community of practice
- Authors: Downsborough, Linda
- Date: 2007
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1878 , http://hdl.handle.net/10962/d1005859
- Description: Learning takes place in a number of ways. Situated learning for example, tries to shift the focus from the individual as a learner to the learner participating in the social world and from learning as a strictly cognitive process to a more encompassing view of social practice. The overall aim of this research was to gain a deeper understanding of the ways in which learning takes place in and between members of a citrus farming community, in other words it was to investigate the social learning processes. The research was undertaken in Patensie, a citrus farming community of the Gamtoos River Valley, Eastern Cape, South Africa. Data was generated through the use of interviews and informal discussions with participants together with document analysis, such as minutes of meetings. I also made observations of the learning interactions that were evident and also the interactions that were evident in the area as a whole. The data was analysed in two phases, the first involved reading across the interview transcripts and organizing the data under broad themes while the second phase made use of an analytical framework, a Community of Practice perspective to further analyze and engage with the data. I drew quite strongly on the ideas of situated learning, Communities of Practice and the notion of Legitimate Peripheral Participation (Lave & Wenger, 1991) as a means to understand, interpret and describe the social learning processes. The research highlighted that in this case study, citrus farmers learn in a number of sociological ways, for example through intergenerational learning (in the family), learning from each other in a Community of Practice, learning from private consultants and extensions officers as well as from other organizations and institutions. It also considered how farmers' learning had influenced land use practice in the area. This brought to the fore an emerging partnership with a conservation agent based on providing economic incentives to farmers to engage in sustainable landuse practices. It is hoped that this research may inform future educational endeavours by shedding light on the social learning processes and by drawing attention to key aspects of learning that may previously have been overlooked in research.
- Full Text:
- Authors: Downsborough, Linda
- Date: 2007
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1878 , http://hdl.handle.net/10962/d1005859
- Description: Learning takes place in a number of ways. Situated learning for example, tries to shift the focus from the individual as a learner to the learner participating in the social world and from learning as a strictly cognitive process to a more encompassing view of social practice. The overall aim of this research was to gain a deeper understanding of the ways in which learning takes place in and between members of a citrus farming community, in other words it was to investigate the social learning processes. The research was undertaken in Patensie, a citrus farming community of the Gamtoos River Valley, Eastern Cape, South Africa. Data was generated through the use of interviews and informal discussions with participants together with document analysis, such as minutes of meetings. I also made observations of the learning interactions that were evident and also the interactions that were evident in the area as a whole. The data was analysed in two phases, the first involved reading across the interview transcripts and organizing the data under broad themes while the second phase made use of an analytical framework, a Community of Practice perspective to further analyze and engage with the data. I drew quite strongly on the ideas of situated learning, Communities of Practice and the notion of Legitimate Peripheral Participation (Lave & Wenger, 1991) as a means to understand, interpret and describe the social learning processes. The research highlighted that in this case study, citrus farmers learn in a number of sociological ways, for example through intergenerational learning (in the family), learning from each other in a Community of Practice, learning from private consultants and extensions officers as well as from other organizations and institutions. It also considered how farmers' learning had influenced land use practice in the area. This brought to the fore an emerging partnership with a conservation agent based on providing economic incentives to farmers to engage in sustainable landuse practices. It is hoped that this research may inform future educational endeavours by shedding light on the social learning processes and by drawing attention to key aspects of learning that may previously have been overlooked in research.
- Full Text:
Research portfolio
- Authors: Hoveka, E P
- Date: 2004
- Subjects: Education -- Namibia Teaching -- Namibia Curriculum planning -- Namibia Educational change -- Namibia English language -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1733 , http://hdl.handle.net/10962/d1003616
- Description: The purpose of this study is to look at English Second Language IGCSE Core Curriculum for Grades 11 and 12. The criteria that has been identified and selected for analysis as stipulated by the Ministry of Basic Education and Culture Language policy Document of 1996 reads as follows: The aim of teaching English as a language should be to enable the learners to increase their participation in the learning processes. This aim was selected as the criteria for investigation because the notion of active participation by the learners in the teaching and learning process places the learners in a different perspective. In other words, the learners are to be seen as possessors of knowledge rather than ‘empty vessels’ as depicted by the behaviourist approach (Van Harmelen 1999). This idea of a learner-centred approach as embedded in Social Constructivism approach is the foundation on which the Namibian Education Reform Process is based. The justification for selecting these particular criteria for close inspection in the English Second Language Curriculum was sparked by the professional attachment of the researcher into teaching English Second Language to Grades 11 and 12 at the Herman Gmeiner Technical School in Swakopmund. The researcher is also serving as a subject head for this particular discipline. Furthermore, evaluating and analyzing the English Second Language curriculum on this particular objective, the researcher hopes to uncover or come to an understanding of how our educational practices have moved from what was practiced under the behavioural approach and to discover the needs of teachers in terms of implementing the new curriculum in their daily practices as educators. Having the criteria stated, the study will focus on how the data was collected and the type of methodology used to gather this information.
- Full Text:
- Authors: Hoveka, E P
- Date: 2004
- Subjects: Education -- Namibia Teaching -- Namibia Curriculum planning -- Namibia Educational change -- Namibia English language -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1733 , http://hdl.handle.net/10962/d1003616
- Description: The purpose of this study is to look at English Second Language IGCSE Core Curriculum for Grades 11 and 12. The criteria that has been identified and selected for analysis as stipulated by the Ministry of Basic Education and Culture Language policy Document of 1996 reads as follows: The aim of teaching English as a language should be to enable the learners to increase their participation in the learning processes. This aim was selected as the criteria for investigation because the notion of active participation by the learners in the teaching and learning process places the learners in a different perspective. In other words, the learners are to be seen as possessors of knowledge rather than ‘empty vessels’ as depicted by the behaviourist approach (Van Harmelen 1999). This idea of a learner-centred approach as embedded in Social Constructivism approach is the foundation on which the Namibian Education Reform Process is based. The justification for selecting these particular criteria for close inspection in the English Second Language Curriculum was sparked by the professional attachment of the researcher into teaching English Second Language to Grades 11 and 12 at the Herman Gmeiner Technical School in Swakopmund. The researcher is also serving as a subject head for this particular discipline. Furthermore, evaluating and analyzing the English Second Language curriculum on this particular objective, the researcher hopes to uncover or come to an understanding of how our educational practices have moved from what was practiced under the behavioural approach and to discover the needs of teachers in terms of implementing the new curriculum in their daily practices as educators. Having the criteria stated, the study will focus on how the data was collected and the type of methodology used to gather this information.
- Full Text:
Processes of transformation in a group psychotherapy intervention for single mothers
- Authors: Spiro, Monica
- Date: 2002
- Subjects: Single mothers -- Psychological aspects Group psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3100 , http://hdl.handle.net/10962/d1004375
- Description: South African and international statistics indicate that single mother families account for a large and growing proportion of the population. The economic, practical, and emotional stresses of single mothering have been documented and the experience of isolation that often accompanies their circumstances is noted in the literature. Group therapy has been utilised as a treatment plan with single mothers to provide social support and to help the women cope with stress. This thesis examines the experience of single mothers who attended a slow, open group therapy intervention for single mothers at the Child Guidance Clinic, University of Cape Town. The study is located in a feminist social constructionist tradition that recognises the multiplicity of social realities. It places the women's experiences at the foreground of the investigation so as to allow for insight into the socially constructed and first-order reality of the respondents. The research investigates the women's subjective experiences of single parenting; their experiences in the group and its impact on them; and their perceptions of group processes that may have facilitated transformation in their lives. Ten members of the single mother groups were selected for in-depth interviews. Five of the most recent graduates were interviewed and five more participants were selected as the five longest standing members currently participating in the groups. The participants' length of stay in the group at the time of interview varied between eight months and five years. The women were drawn from a range of race, class, cultural and educational backgrounds. The data was collected using individual semi-structured in -depth interviews. A constructivist grounded theory approach was employed to analyse the data. Results revealed the value of the group therapy intervention as a transformative experience for these women who face the challenges of being single parents. The participants highlighted the interpersonal factor of the group intervention as central to their experience and identified this relational aspect as the unique site of their emotional growth. The five interpersonal factors that were identified are: non-judgemental acceptance; support; commonality of experience; reciprocity; and challenge and confrontation between group members. Their accounts of personal changes brought about by participation in the group reflect internal intrapsychic transformations, which are understood in terms of increased se lf-acceptance, enhanced self-esteem, and improved self-confidence. Furthermore, their accounts of personal transformations include a reorganisation of their relational patterns from their immediate to their larger social context. The centrality of relational processes in this research reinforces contemporary theory of women's psychology, particularly theory emerging from the Stone Center, which offers a view of women's psychological growth as occurring in and through participation and engagement with others to achieve more mature and satisfying forms of relating. The accounts of personal and collective transformation provide further insight in to the concept of relational empowerment as it occurs in these groups and offer an understanding of the potentially restorative value of group therapy for single mothers. Future therapeutic interventions are considered and the need for further research in the field is discussed.
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- Authors: Spiro, Monica
- Date: 2002
- Subjects: Single mothers -- Psychological aspects Group psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3100 , http://hdl.handle.net/10962/d1004375
- Description: South African and international statistics indicate that single mother families account for a large and growing proportion of the population. The economic, practical, and emotional stresses of single mothering have been documented and the experience of isolation that often accompanies their circumstances is noted in the literature. Group therapy has been utilised as a treatment plan with single mothers to provide social support and to help the women cope with stress. This thesis examines the experience of single mothers who attended a slow, open group therapy intervention for single mothers at the Child Guidance Clinic, University of Cape Town. The study is located in a feminist social constructionist tradition that recognises the multiplicity of social realities. It places the women's experiences at the foreground of the investigation so as to allow for insight into the socially constructed and first-order reality of the respondents. The research investigates the women's subjective experiences of single parenting; their experiences in the group and its impact on them; and their perceptions of group processes that may have facilitated transformation in their lives. Ten members of the single mother groups were selected for in-depth interviews. Five of the most recent graduates were interviewed and five more participants were selected as the five longest standing members currently participating in the groups. The participants' length of stay in the group at the time of interview varied between eight months and five years. The women were drawn from a range of race, class, cultural and educational backgrounds. The data was collected using individual semi-structured in -depth interviews. A constructivist grounded theory approach was employed to analyse the data. Results revealed the value of the group therapy intervention as a transformative experience for these women who face the challenges of being single parents. The participants highlighted the interpersonal factor of the group intervention as central to their experience and identified this relational aspect as the unique site of their emotional growth. The five interpersonal factors that were identified are: non-judgemental acceptance; support; commonality of experience; reciprocity; and challenge and confrontation between group members. Their accounts of personal changes brought about by participation in the group reflect internal intrapsychic transformations, which are understood in terms of increased se lf-acceptance, enhanced self-esteem, and improved self-confidence. Furthermore, their accounts of personal transformations include a reorganisation of their relational patterns from their immediate to their larger social context. The centrality of relational processes in this research reinforces contemporary theory of women's psychology, particularly theory emerging from the Stone Center, which offers a view of women's psychological growth as occurring in and through participation and engagement with others to achieve more mature and satisfying forms of relating. The accounts of personal and collective transformation provide further insight in to the concept of relational empowerment as it occurs in these groups and offer an understanding of the potentially restorative value of group therapy for single mothers. Future therapeutic interventions are considered and the need for further research in the field is discussed.
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An analysis of some school history textbooks with special reference to styles of concept presentation
- Matoti, Sukude Mangwevandile
- Authors: Matoti, Sukude Mangwevandile
- Date: 1990
- Subjects: History -- Study and teaching -- South Africa -- Textbooks -- Evaluation , South Africa -- History -- Textbooks
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1343 , http://hdl.handle.net/10962/d1001409
- Description: The aim of this study was to find out whether the school history textbooks used in Transkei Junior and Senior secondary schools were adequate in helping pupils meet the demands of their course. The results of the study would be used as argument for or against the assumption that the type of textbooks used in Transkei schools, through their inadequacy in equipping the pupils with the necessary skills for "doing" history, do contribute to the high failure rate in history, especially that they are in most schools, the only recourse for both the teacher and the pupil. In particular the study intended to see what strategies the history textbooks used to aid concept understanding which is crucial to the understanding of history. Twenty three criteria, fourteen objective and nine subjective were used to assess the books for readability and for strategies which might aid concept understanding. Eight books were assessed: four Std 5 and four Std 8 books. The results showed that only three of the eight books catered for the development of skills of learning history and were suited to the level of the pupiils for whom they were intended . History textbooks therefore need to be improved so as to foster the skills of learning history. Their inadequacy could be a contributory factor to the high rate of failure. In-service and pre-service training in methods of textbook analysis can assist in textbook selection and for changes in methods of teaching to supplement shortcomings in books which are commonly used
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- Authors: Matoti, Sukude Mangwevandile
- Date: 1990
- Subjects: History -- Study and teaching -- South Africa -- Textbooks -- Evaluation , South Africa -- History -- Textbooks
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1343 , http://hdl.handle.net/10962/d1001409
- Description: The aim of this study was to find out whether the school history textbooks used in Transkei Junior and Senior secondary schools were adequate in helping pupils meet the demands of their course. The results of the study would be used as argument for or against the assumption that the type of textbooks used in Transkei schools, through their inadequacy in equipping the pupils with the necessary skills for "doing" history, do contribute to the high failure rate in history, especially that they are in most schools, the only recourse for both the teacher and the pupil. In particular the study intended to see what strategies the history textbooks used to aid concept understanding which is crucial to the understanding of history. Twenty three criteria, fourteen objective and nine subjective were used to assess the books for readability and for strategies which might aid concept understanding. Eight books were assessed: four Std 5 and four Std 8 books. The results showed that only three of the eight books catered for the development of skills of learning history and were suited to the level of the pupiils for whom they were intended . History textbooks therefore need to be improved so as to foster the skills of learning history. Their inadequacy could be a contributory factor to the high rate of failure. In-service and pre-service training in methods of textbook analysis can assist in textbook selection and for changes in methods of teaching to supplement shortcomings in books which are commonly used
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Application of high-performance liquid chromatography to the analysis, stability and pharmacokinetics of erythromycin
- Authors: Stubbs, Christopher
- Date: 1988
- Subjects: Erythromycin High performance liquid chromatography
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3809 , http://hdl.handle.net/10962/d1004372
- Description: Erythromycin is a macrolide antibiotic used mainly in the treatment of infections caused by gram-positive organisms. Erythromycin base is rap idly degraded in acidic media necessitating the use of structurally modified erythromycin derivatives or acid resistant dosage forms in order to decrease gastric inactivation of the drug. The majority of pharmacokinetic studies to-date have utilized relatively non-specific microbiological assay procedures which are unable to differentiate between concentrations of active erythromycin base and the inactive pro-drug derivatives. A high-performance liquid chromatographic (HPLC) technique is described for the simultaneous determination of erythromycin base and propionate (inactive pro-drug form) in human serum and urine following the oral administration of erythromycin estolate, an acid stable derivative of erythromycin. The method involves a solid-phase extraction step prior to chromatography on a C18 reversed-phase column with coulometric electrochemical detection. Sample handling and storage techniques are presented which minimize hydrolysis of the inactive ester moiety between sample collection and analysis, thereby more accurately reflecting the in vivo situation than in previously published studies. Results from single dose pharmacokinetic studies indicate that only 10-15% of the total erythromycin concentration in vivo is present as the active base component following oral administration of erythromycin estolate. This percentage increases to approximately 25% during multiple dose administration. Novel urinary excretion data are presented which reveal that approximately 40% and 55% of the total erythromycin excreted in urine is excreted as erythromycin base following single and multiple dosages respectively. Computer fitting of mean serum concentration-time data revealed that an open one compartment model with linear first order absorption and elimination best described the absorption and disposition of erythromycin, although poor computer fits for individual data sets were observed. Some evidence of non-linear elimination is presented utilizing both compartmental and non-compartmental pharmacokinetic techniques. Large intra-and inter-personal variability in erythromycin absorption and disposition was experienced which was evaluated in five subjects who each received one 500 mg erythromycin estolate tablet from the same batch, on three separate occasions. In addition. an HPLC method is described for the analysis of "total erythromycin" concentrations following erythromycin estolate administration which involves hydrolysis of the ester component prior to chromatography. as well as an HPLC method utilizing amperometric electrochemical detection capable of monitoring the stability of erythromycin base in stored biological fluids. These methods were uti I ized in various stability studies involving erythromycin base and propionate as well as for the analysis of erythromycin estolate dosage forms.
- Full Text:
- Authors: Stubbs, Christopher
- Date: 1988
- Subjects: Erythromycin High performance liquid chromatography
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3809 , http://hdl.handle.net/10962/d1004372
- Description: Erythromycin is a macrolide antibiotic used mainly in the treatment of infections caused by gram-positive organisms. Erythromycin base is rap idly degraded in acidic media necessitating the use of structurally modified erythromycin derivatives or acid resistant dosage forms in order to decrease gastric inactivation of the drug. The majority of pharmacokinetic studies to-date have utilized relatively non-specific microbiological assay procedures which are unable to differentiate between concentrations of active erythromycin base and the inactive pro-drug derivatives. A high-performance liquid chromatographic (HPLC) technique is described for the simultaneous determination of erythromycin base and propionate (inactive pro-drug form) in human serum and urine following the oral administration of erythromycin estolate, an acid stable derivative of erythromycin. The method involves a solid-phase extraction step prior to chromatography on a C18 reversed-phase column with coulometric electrochemical detection. Sample handling and storage techniques are presented which minimize hydrolysis of the inactive ester moiety between sample collection and analysis, thereby more accurately reflecting the in vivo situation than in previously published studies. Results from single dose pharmacokinetic studies indicate that only 10-15% of the total erythromycin concentration in vivo is present as the active base component following oral administration of erythromycin estolate. This percentage increases to approximately 25% during multiple dose administration. Novel urinary excretion data are presented which reveal that approximately 40% and 55% of the total erythromycin excreted in urine is excreted as erythromycin base following single and multiple dosages respectively. Computer fitting of mean serum concentration-time data revealed that an open one compartment model with linear first order absorption and elimination best described the absorption and disposition of erythromycin, although poor computer fits for individual data sets were observed. Some evidence of non-linear elimination is presented utilizing both compartmental and non-compartmental pharmacokinetic techniques. Large intra-and inter-personal variability in erythromycin absorption and disposition was experienced which was evaluated in five subjects who each received one 500 mg erythromycin estolate tablet from the same batch, on three separate occasions. In addition. an HPLC method is described for the analysis of "total erythromycin" concentrations following erythromycin estolate administration which involves hydrolysis of the ester component prior to chromatography. as well as an HPLC method utilizing amperometric electrochemical detection capable of monitoring the stability of erythromycin base in stored biological fluids. These methods were uti I ized in various stability studies involving erythromycin base and propionate as well as for the analysis of erythromycin estolate dosage forms.
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Aspects of the biology and population dynamics of the geelbek Atractoscion aequidens (Cuvier) (Pisces: Sciaenidae) off the South African coast
- Authors: Griffiths, Marc H
- Date: 1988
- Subjects: Sciaenidae -- South Africa Fish populations -- South Africa Atractoscion Atractoscion -- South Africa -- Ecology Atractoscion -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5194 , http://hdl.handle.net/10962/d1001970
- Description: The geelbek Atractoscion aeguidens is an important commercial and recreational linefish species along the South African eastern seaboard . Aspects of its biology and population dynamics were investigated using data collected from various sampling sites along the South African east coast and from catch statistics obtained from both the Sea Fisheries Research Institute (Cape Town), and dealer records. The biological aspects studied included age and growth, reproduction and feeding. It was established that A. aeguidens is a fast growing species with a relatively late age at sexual maturity and a 1:1 sex ratio. Feeding studies revealed that it has become specialized to feed on small pelagic fish. The South African geelbek stock consists of three distinct age related sub-populations, each representing a particular phase in the life cycle. The sub-adults (1-4 yrs) occur in the South West Cape and feed predominantly on anchovy, Engraulis capensis, which they follow, moving inshore in summer and offshore in winter. The adults (5-9 yrs) undergo a seasonal inshore migration to Natal where they spawn in spring. The dynamics of this migration are strongly influenced by the annual movement of their principal prey viz. , Sardinops ocellatus, to that region. As a result the geelbek first arrive in Natal during mid winter. Evidence is also presented to suggest that a significant number of "adolescent " fish (4-5 yrs) undergo limited gonad maturation and a partial migration to at least as far as the South East Cape. Spawning appears to occur offshore. It is postulated that eggs and larvae are transported southwards by the peripheral waters of the Agulhas Current. After spawning the adults probably remain offshore and use the current to aid their return to the South and South West Cape, where they spend summer feeding on the Agulhas Bank. Juveniles (<1 yr) first appear in the South East Cape between January and March. They apparently use this region as a nursery area for almost a year before moving southwards to join the sub-adults in the South West Cape. In the South East Cape, the juveniles feed initially on mysids whereafter they switch to anchovies and pilchards. A preliminary stock assessment using yield per recruit and spawner biomass per recruit models, indicated that despite the current legislation the South African geelbek population is already overexploited. This is largely attributed to high rates of fishing mortality of the migratory adult population. Further management recommendations are therefore proposed. These include a size limit (660 mm FL), derived from an investigation of the interrelationship between natural mortality and somatic growth in a theoretical unexploited cohort, as well as a uniform bag limit for all user groups (5 fish per person per day)
- Full Text:
- Authors: Griffiths, Marc H
- Date: 1988
- Subjects: Sciaenidae -- South Africa Fish populations -- South Africa Atractoscion Atractoscion -- South Africa -- Ecology Atractoscion -- South Africa -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5194 , http://hdl.handle.net/10962/d1001970
- Description: The geelbek Atractoscion aeguidens is an important commercial and recreational linefish species along the South African eastern seaboard . Aspects of its biology and population dynamics were investigated using data collected from various sampling sites along the South African east coast and from catch statistics obtained from both the Sea Fisheries Research Institute (Cape Town), and dealer records. The biological aspects studied included age and growth, reproduction and feeding. It was established that A. aeguidens is a fast growing species with a relatively late age at sexual maturity and a 1:1 sex ratio. Feeding studies revealed that it has become specialized to feed on small pelagic fish. The South African geelbek stock consists of three distinct age related sub-populations, each representing a particular phase in the life cycle. The sub-adults (1-4 yrs) occur in the South West Cape and feed predominantly on anchovy, Engraulis capensis, which they follow, moving inshore in summer and offshore in winter. The adults (5-9 yrs) undergo a seasonal inshore migration to Natal where they spawn in spring. The dynamics of this migration are strongly influenced by the annual movement of their principal prey viz. , Sardinops ocellatus, to that region. As a result the geelbek first arrive in Natal during mid winter. Evidence is also presented to suggest that a significant number of "adolescent " fish (4-5 yrs) undergo limited gonad maturation and a partial migration to at least as far as the South East Cape. Spawning appears to occur offshore. It is postulated that eggs and larvae are transported southwards by the peripheral waters of the Agulhas Current. After spawning the adults probably remain offshore and use the current to aid their return to the South and South West Cape, where they spend summer feeding on the Agulhas Bank. Juveniles (<1 yr) first appear in the South East Cape between January and March. They apparently use this region as a nursery area for almost a year before moving southwards to join the sub-adults in the South West Cape. In the South East Cape, the juveniles feed initially on mysids whereafter they switch to anchovies and pilchards. A preliminary stock assessment using yield per recruit and spawner biomass per recruit models, indicated that despite the current legislation the South African geelbek population is already overexploited. This is largely attributed to high rates of fishing mortality of the migratory adult population. Further management recommendations are therefore proposed. These include a size limit (660 mm FL), derived from an investigation of the interrelationship between natural mortality and somatic growth in a theoretical unexploited cohort, as well as a uniform bag limit for all user groups (5 fish per person per day)
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The Hasidic spirit as the foundation of the art of Marc Chagall
- Authors: Bagraim, Abigail Sarah
- Date: 1987
- Subjects: Chagall, Marc, 1887-1985 Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2393 , http://hdl.handle.net/10962/d1002189
- Description: In considering Chagall's art the observer is immediately struck by the constancy of his almost obsessive repetition of certain symbols and themes. In this way Chagall has created his own fantasy world, one with which the observer soon becomes acquainted and grows to love and understand.
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- Authors: Bagraim, Abigail Sarah
- Date: 1987
- Subjects: Chagall, Marc, 1887-1985 Criticism and interpretation
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: vital:2393 , http://hdl.handle.net/10962/d1002189
- Description: In considering Chagall's art the observer is immediately struck by the constancy of his almost obsessive repetition of certain symbols and themes. In this way Chagall has created his own fantasy world, one with which the observer soon becomes acquainted and grows to love and understand.
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The ecology and control of Opuntia Aurantiaca in South Africa in relation to the cochineal insect, Dactylopius Austrinus
- Authors: Zimmermann, Helmuth G
- Date: 1982
- Subjects: Cochineal insect -- South Africa Cactus -- South Africa Weeds -- Control -- South Africa Insect-plant relationships
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5612 , http://hdl.handle.net/10962/d1003061
- Description: The cochineal insect Dactylopius austrinus De Lotto, which was released on jointed cactus, Opuntia aurantiaca Lindley, in South Africa in 1932, failed to bring the weed under an acceptable level of control in spite of the encouraging results during the first few years after release. The reasons for this apparent failure were never clearly understood. In 1957 the State embarked on an intensive herbicidal control programme which is still in force today. This sustained and expensive programme has undoubtedly reduced the density of the weed in most areas but has failed to solve the problem and the plant continues to expand its range. The biological control of o. aurantiaca in South Africa has been fundamentally influenced by this chemical control campaign. The relationship between chemical and biological control methods is reported in this study.
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- Authors: Zimmermann, Helmuth G
- Date: 1982
- Subjects: Cochineal insect -- South Africa Cactus -- South Africa Weeds -- Control -- South Africa Insect-plant relationships
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5612 , http://hdl.handle.net/10962/d1003061
- Description: The cochineal insect Dactylopius austrinus De Lotto, which was released on jointed cactus, Opuntia aurantiaca Lindley, in South Africa in 1932, failed to bring the weed under an acceptable level of control in spite of the encouraging results during the first few years after release. The reasons for this apparent failure were never clearly understood. In 1957 the State embarked on an intensive herbicidal control programme which is still in force today. This sustained and expensive programme has undoubtedly reduced the density of the weed in most areas but has failed to solve the problem and the plant continues to expand its range. The biological control of o. aurantiaca in South Africa has been fundamentally influenced by this chemical control campaign. The relationship between chemical and biological control methods is reported in this study.
- Full Text: