Photoconductive spectroscopy of GaSb thin films
- Authors: Shura, Megersa Wodajo
- Date: 2012
- Subjects: Photoelectron spectroscopy , Photoconductivity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10549 , http://hdl.handle.net/10948/d1019937
- Description: In this study, we have investigated the photo-response of gallium antimonide (GaSb) by measuring the spectral, injection level, as well as the temperature dependence of the steady-state photoconductivity of epitaxial films. By combining the various photo-response measurements with-galvanometric measurements, the effective excess carrier lifetimes could be calculated and described in terms of the various experimental variables considered. From a comparison of the measured and theoretical carrier lifetimes, a clear discrepancy was found for the injection dependent results. This inconsistency between the expected and measured behaviours was resolved using a two-layer model to describe the photo-conductive response of the thin film. In this model, the generation/recombination processes are considered for the bulk as well as for a depleted near-surface region. By combining these two contributions when calculating the total excess photocurrent, the various experimental results could be successfully described. The photo-response measurements revealed that the main contribution to the photocurrent came from the near-surface region, where the bandto- band and Auger recombination transitions are reduced. From the simulation of the injection level dependence of the excess carrier lifetime, some of the near-surface characteristics, such as the position of the surface Fermi-level and the surface recombination velocity, could be determined. In the case of p-type GaSb, the room temperature surface Fermi-level was found to be pinned (290±20) meV above the valence band maximum, whereas the n-type material had a pinning position of (150±20) meV above the valence band maximum. These pinning positions were shown to be independent of the doping density and relatively insensitive to the surface treatments considered. The presence of a near-surface depletion region, as well as the position of the surface Fermi-level, was corroborated by Raman spectroscopy. From a comparison of the phonon mode and the phonon-hole plasmon coupled mode, a surface Fermi-level position of (300 ± 30) meV was deduced for p-type GaSb. Finally, the effect various surface treatments have on the photo-response, and related surface properties, were investigated. Removal of the native oxide (HCl:H2O) followed by sulphur passivation (Na2S:9H2O) results in a slight decrease in the surface Fermi-level position. Aging studies however revealed that the surface characteristics reverted back to the untreated values following a few days in air. Coating the GaSb surfaces with a thin ZnS layer was found to have little effect on the surface potential, resulting only in a slight increase in the near-surface donor density. The sensitivity of the measured photocurrent to surface treatments and changes in the ambient with cooling, further validate the importance of considering the surface potential and the related space-charge when describing the photoconductive response of GaSb thin films.
- Full Text:
- Date Issued: 2012
- Authors: Shura, Megersa Wodajo
- Date: 2012
- Subjects: Photoelectron spectroscopy , Photoconductivity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10549 , http://hdl.handle.net/10948/d1019937
- Description: In this study, we have investigated the photo-response of gallium antimonide (GaSb) by measuring the spectral, injection level, as well as the temperature dependence of the steady-state photoconductivity of epitaxial films. By combining the various photo-response measurements with-galvanometric measurements, the effective excess carrier lifetimes could be calculated and described in terms of the various experimental variables considered. From a comparison of the measured and theoretical carrier lifetimes, a clear discrepancy was found for the injection dependent results. This inconsistency between the expected and measured behaviours was resolved using a two-layer model to describe the photo-conductive response of the thin film. In this model, the generation/recombination processes are considered for the bulk as well as for a depleted near-surface region. By combining these two contributions when calculating the total excess photocurrent, the various experimental results could be successfully described. The photo-response measurements revealed that the main contribution to the photocurrent came from the near-surface region, where the bandto- band and Auger recombination transitions are reduced. From the simulation of the injection level dependence of the excess carrier lifetime, some of the near-surface characteristics, such as the position of the surface Fermi-level and the surface recombination velocity, could be determined. In the case of p-type GaSb, the room temperature surface Fermi-level was found to be pinned (290±20) meV above the valence band maximum, whereas the n-type material had a pinning position of (150±20) meV above the valence band maximum. These pinning positions were shown to be independent of the doping density and relatively insensitive to the surface treatments considered. The presence of a near-surface depletion region, as well as the position of the surface Fermi-level, was corroborated by Raman spectroscopy. From a comparison of the phonon mode and the phonon-hole plasmon coupled mode, a surface Fermi-level position of (300 ± 30) meV was deduced for p-type GaSb. Finally, the effect various surface treatments have on the photo-response, and related surface properties, were investigated. Removal of the native oxide (HCl:H2O) followed by sulphur passivation (Na2S:9H2O) results in a slight decrease in the surface Fermi-level position. Aging studies however revealed that the surface characteristics reverted back to the untreated values following a few days in air. Coating the GaSb surfaces with a thin ZnS layer was found to have little effect on the surface potential, resulting only in a slight increase in the near-surface donor density. The sensitivity of the measured photocurrent to surface treatments and changes in the ambient with cooling, further validate the importance of considering the surface potential and the related space-charge when describing the photoconductive response of GaSb thin films.
- Full Text:
- Date Issued: 2012
Photophysicochemical and photodynamic studies of phthalocyanines conjugated to selected drug delivery agents
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
- Full Text:
- Date Issued: 2012
- Authors: Nombona, Nolwazi
- Date: 2012
- Subjects: Phthalocyanines Photochemistry Photochemotherapy Drug delivery systems Magnesium Zinc Nanoparticles Staphylococcus aureus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4333 , http://hdl.handle.net/10962/d1004994
- Description: This work reports on the successful synthesis, characterisation and photophysical properties of new asymmetric metal free, magnesium and zinc phthalocyanines. The synthesis of symmetrical phthalocyanines is also reported. A selection of phthalocyanines have been conjugated, covalently linked, encapsulated or mixed with selected of drug delivery agents which include gold or silver nanoparticles, poly-L-lysine, liposomes and folic acid. The influence of delivery agent on the photophysical and photochemical properties of conjugated phthalocyanine is investigated. The studies showed that the Au nanoparticle significantly lowered the fluorescence quantum yield values of the phthalocyanines. The photodynamic activity of Zn phthalocyanine-ε-polylysine conjugates in the presence of nanoparticles towards the inactivation of Staphylococcus aureus showed high photoinactivation in the presence of silver nanoparticles. The presence of silver nanoparticels from the minimal inhibition concentration (MIC₅₀) studies showed remarkable growth inhibition for the tested conjugates even at low concentrations. The conjugate also showed no dark toxicity when evaluated using the chick choriallantoic membrane (CAM) assay. The efficiency of selected zinc phthalocyanine as photodynamic therapy (PDT) agents was investigated. The production of reactive oxygen species (ROS) and phototoxicity of the photosensitizers were assessed. Healthy fibroblast cells and breast cancer (MCF-7) cells were treated with either free phthalocyanine or phthalocyanine bound to either gold nanoparticles or encapsulated in liposomes. Cell viability studies showed the optimum phototoxic effect on non-malignant cells to be 4.5 J.cm⁻². The PDT effect of the liposome bound phthalocyanine showed extensive damage of the breast cancer cells. Gold nanoparticles only showed a modest improvement in PDT activity.
- Full Text:
- Date Issued: 2012
Photophysicochemical studies of phenylthio phthalocyanines interaction with gold nanoparticles and applications in dye sensitised solar cells and optical limiting
- Authors: Forteath, Shaun
- Date: 2012
- Subjects: Phthalocyanines , Nanoparticles , Photochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4334 , http://hdl.handle.net/10962/d1004995 , Phthalocyanines , Nanoparticles , Photochemistry
- Description: The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.
- Full Text:
- Date Issued: 2012
- Authors: Forteath, Shaun
- Date: 2012
- Subjects: Phthalocyanines , Nanoparticles , Photochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4334 , http://hdl.handle.net/10962/d1004995 , Phthalocyanines , Nanoparticles , Photochemistry
- Description: The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.
- Full Text:
- Date Issued: 2012
Physico-chemical and microalgal characteristics of the Goukamma Estuary
- Authors: Kaselowski, Tanja
- Date: 2012
- Subjects: Estuarine ecology , Estuaries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10623 , http://hdl.handle.net/10948/d1011130 , Estuarine ecology , Estuaries -- South Africa
- Description: Estuaries are intrinsically complex and dynamic ecosystems that display marked spatial and temporal variability. Because estuaries are situated at the receiving end of catchment activities, they are at particular risk of alterations to their natural complexity. The overarching objective of this study was to gain an overview of the abiotic conditions and biotic response of the Goukamma Estuary, a small temporarily open/closed estuary (TOCE) which is situated in a relatively undisturbed catchment in the Southern Cape. Physico-chemical properties drive estuarine ecology, and together with biological indicators, are commonly assessed to determine the present status of an estuary. During the study, physico-chemical parameters reflected great spatial and temporal variability in response to the mouth state over a 13 month period. Parameters ranged within expected limits, as proposed by the conceptual model for water quality of TOCE’s (Snow and Taljaard 2007). Of particular importance was the prominent occurrence of salinity stratification and hypoxic conditions (dissolved oxygen [DO] < 3 mg l-1) during both open and closed mouth states. Data indicated that in the wide and shallow lower reaches, weak stratification gradients were present and oxygenated conditions (DO > 6 mg l-1) were maintained throughout the water column mainly by wind and tidal action. However, stratification increased towards the deeper, channel-like middle and upper reaches of the estuary, followed by a significant reduction in bottom DO concentrations and development of hypoxia and anoxia. Bottom water hypoxia commonly occurs in microtidal estuaries due to the limited influence of mixing forces, mainly by wind and tidal action. The Goukamma Estuary is a channel-like microtidal estuary where stratification effectively limited oxygenation of the bottom water which resulted in frequent occurrence of bottom water hypoxia. During June 2010 when the highest local rainfall (75 mm) was recorded for the region, salinity and DO data showed that this amount of rainfall was insignificant as it did not replenish the water column of oxygen. Only the surface 0.5 m layer was fresh and oxygenated while below this, the water column was completely hypoxic. In an unimpacted state, the Goukamma Estuary is a blackwater system and is expected to be nutrient poor; however, farming activities in the catchment have resulted in elevated nutrient concentrations. This study showed that significantly higher nutrient concentrations were measured in the middle and upper reaches of the estuary, adjacent to cattle farms situated in the floodplain of these reaches. Nutrient concentrations represented mesotrophic (dissolved inorganic nitrogen [DIN] > 500 μg l-1) to eutrophic conditions (dissolved inorganic phosphorus [DIP] > 25 μg l-1). Nutrient input stimulated phytoplankton to attain a significantly high biomass, ranging between 0.3 – 112 μg l-1 (~ 7.7 ± 1.3 μg l-1; n = 128) and 0.8 – 289 μg l-1 (~ 21.1 ± 4.4 μg l-1; n = 80) during the open and closed states, respectively. High organic loads are associated with high oxygen demands which consequently result in hypoxia following decomposition. Exacerbated by natural salinity stratification which effectively limits oxygenation of the water column, unnaturally high nutrient concentrations and coinciding organic loads place the estuary at particular risk of degradation. This study captured key patterns and processes by quantifying salinity, oxygen and nutrient concentrations in addition to biological indicators (phytoplankton biomass and community composition). Considering possible budget constraints, it is recommended that monthly salinity and oxygen concentrations should be monitored as well as seasonal nutrient concentrations. It is also recommended that riparian buffer zones should be established in the middle and upper reaches of the estuary, as these vegetation buffers have been well documented to contribute to nutrient attenuation and improved water quality from agricultural run-off.
- Full Text:
- Date Issued: 2012
- Authors: Kaselowski, Tanja
- Date: 2012
- Subjects: Estuarine ecology , Estuaries -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10623 , http://hdl.handle.net/10948/d1011130 , Estuarine ecology , Estuaries -- South Africa
- Description: Estuaries are intrinsically complex and dynamic ecosystems that display marked spatial and temporal variability. Because estuaries are situated at the receiving end of catchment activities, they are at particular risk of alterations to their natural complexity. The overarching objective of this study was to gain an overview of the abiotic conditions and biotic response of the Goukamma Estuary, a small temporarily open/closed estuary (TOCE) which is situated in a relatively undisturbed catchment in the Southern Cape. Physico-chemical properties drive estuarine ecology, and together with biological indicators, are commonly assessed to determine the present status of an estuary. During the study, physico-chemical parameters reflected great spatial and temporal variability in response to the mouth state over a 13 month period. Parameters ranged within expected limits, as proposed by the conceptual model for water quality of TOCE’s (Snow and Taljaard 2007). Of particular importance was the prominent occurrence of salinity stratification and hypoxic conditions (dissolved oxygen [DO] < 3 mg l-1) during both open and closed mouth states. Data indicated that in the wide and shallow lower reaches, weak stratification gradients were present and oxygenated conditions (DO > 6 mg l-1) were maintained throughout the water column mainly by wind and tidal action. However, stratification increased towards the deeper, channel-like middle and upper reaches of the estuary, followed by a significant reduction in bottom DO concentrations and development of hypoxia and anoxia. Bottom water hypoxia commonly occurs in microtidal estuaries due to the limited influence of mixing forces, mainly by wind and tidal action. The Goukamma Estuary is a channel-like microtidal estuary where stratification effectively limited oxygenation of the bottom water which resulted in frequent occurrence of bottom water hypoxia. During June 2010 when the highest local rainfall (75 mm) was recorded for the region, salinity and DO data showed that this amount of rainfall was insignificant as it did not replenish the water column of oxygen. Only the surface 0.5 m layer was fresh and oxygenated while below this, the water column was completely hypoxic. In an unimpacted state, the Goukamma Estuary is a blackwater system and is expected to be nutrient poor; however, farming activities in the catchment have resulted in elevated nutrient concentrations. This study showed that significantly higher nutrient concentrations were measured in the middle and upper reaches of the estuary, adjacent to cattle farms situated in the floodplain of these reaches. Nutrient concentrations represented mesotrophic (dissolved inorganic nitrogen [DIN] > 500 μg l-1) to eutrophic conditions (dissolved inorganic phosphorus [DIP] > 25 μg l-1). Nutrient input stimulated phytoplankton to attain a significantly high biomass, ranging between 0.3 – 112 μg l-1 (~ 7.7 ± 1.3 μg l-1; n = 128) and 0.8 – 289 μg l-1 (~ 21.1 ± 4.4 μg l-1; n = 80) during the open and closed states, respectively. High organic loads are associated with high oxygen demands which consequently result in hypoxia following decomposition. Exacerbated by natural salinity stratification which effectively limits oxygenation of the water column, unnaturally high nutrient concentrations and coinciding organic loads place the estuary at particular risk of degradation. This study captured key patterns and processes by quantifying salinity, oxygen and nutrient concentrations in addition to biological indicators (phytoplankton biomass and community composition). Considering possible budget constraints, it is recommended that monthly salinity and oxygen concentrations should be monitored as well as seasonal nutrient concentrations. It is also recommended that riparian buffer zones should be established in the middle and upper reaches of the estuary, as these vegetation buffers have been well documented to contribute to nutrient attenuation and improved water quality from agricultural run-off.
- Full Text:
- Date Issued: 2012
Phytochemical analysis and bioactivity of Garcinia Kola (Heckel) seeds on selected bacterial pathogens
- Seanego, Christinah Tshephisho
- Authors: Seanego, Christinah Tshephisho
- Date: 2012
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11259 , http://hdl.handle.net/10353/420 , Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Description: Garcinia kola is one of the plants used in folklore remedies for the treatment of microbial infections. Bacterial resistance to commonly used antibiotics has necessitated the search for newer and alternative compounds for the treatment of drug resistant microbial infections. This study focuses on the bioactivity of G. kola seeds on Streptococcus pyogenes (ATCC 49399), Staphylococcus aureus (NCTC 6571), Plesiomonas Shigelloides (ATCC 51903) and Salmonella typhimurium (ATCC 13311), organisms which can cause illnesses from mild to severe with potentially fatal outcomes. The crude ethyl acetate, ethanol, methanol, acetone and aqueous extracts were screened by agar-well diffusion method and the activities of the extract were further determined by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. The inhibition zones ranged from 0 - 24 mm, while MIC and MBC of the extract ranged between 0.04 - 1.25 mg/mL and 0.081 - 2.5 mg/mL respectively. Chloroform/ Ethyl Acetate/ Formic acid (CEF) solvent system separated more active compounds followed by Ethyl Acetate/ Methanol/ Water (EMW) and Benzene/ Ethanol/ Ammonium Hydroxide (BEA). The extracts were fractionated by Thin Layer Chromatography (TLC). Bioautography was used to assess the activity of the possible classes of compounds present in the more active extracts. Column chromatography was used to purify the active compounds from the mixture while Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify the phyto components of the fractions. The MIC of the fractions ranged between 0.0006 - 2.5 mg/mL. CEF 3 (F3), CEF 11 (F11) and CEF 12 (F12) revealed the presence of high levels fatty acids Linoleic acid, 1, 2-Benzenedicarboxylic acid and 2, 3-Dihydro-3, 5-dihydroxy-6-methyl, respectively. The results obtained from this study justify the use of this plant in traditional medicine and provide leads which could be further exploited for the development of new and potent antimicrobials.
- Full Text:
- Date Issued: 2012
- Authors: Seanego, Christinah Tshephisho
- Date: 2012
- Subjects: Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11259 , http://hdl.handle.net/10353/420 , Drug resistance in microorganisms , Garcinia , Antibiotics , Medicinal plants , Microbial sensitivity tests , Streptococcal infections , Streptococcus , Staphylococcus aureus infections , Salmonella typhimurium , Traditional medicine
- Description: Garcinia kola is one of the plants used in folklore remedies for the treatment of microbial infections. Bacterial resistance to commonly used antibiotics has necessitated the search for newer and alternative compounds for the treatment of drug resistant microbial infections. This study focuses on the bioactivity of G. kola seeds on Streptococcus pyogenes (ATCC 49399), Staphylococcus aureus (NCTC 6571), Plesiomonas Shigelloides (ATCC 51903) and Salmonella typhimurium (ATCC 13311), organisms which can cause illnesses from mild to severe with potentially fatal outcomes. The crude ethyl acetate, ethanol, methanol, acetone and aqueous extracts were screened by agar-well diffusion method and the activities of the extract were further determined by Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays. The inhibition zones ranged from 0 - 24 mm, while MIC and MBC of the extract ranged between 0.04 - 1.25 mg/mL and 0.081 - 2.5 mg/mL respectively. Chloroform/ Ethyl Acetate/ Formic acid (CEF) solvent system separated more active compounds followed by Ethyl Acetate/ Methanol/ Water (EMW) and Benzene/ Ethanol/ Ammonium Hydroxide (BEA). The extracts were fractionated by Thin Layer Chromatography (TLC). Bioautography was used to assess the activity of the possible classes of compounds present in the more active extracts. Column chromatography was used to purify the active compounds from the mixture while Gas Chromatography-Mass Spectrometry (GC-MS) was used to identify the phyto components of the fractions. The MIC of the fractions ranged between 0.0006 - 2.5 mg/mL. CEF 3 (F3), CEF 11 (F11) and CEF 12 (F12) revealed the presence of high levels fatty acids Linoleic acid, 1, 2-Benzenedicarboxylic acid and 2, 3-Dihydro-3, 5-dihydroxy-6-methyl, respectively. The results obtained from this study justify the use of this plant in traditional medicine and provide leads which could be further exploited for the development of new and potent antimicrobials.
- Full Text:
- Date Issued: 2012
Phytoplankton associated with mesoscale eddies in the Mozambique Channel
- Authors: O'Reilly, Bevan James
- Date: 2012
- Subjects: Mozambique Channel. , Phytoplankton
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10622 , http://hdl.handle.net/10948/d1010967 , Mozambique Channel. , Phytoplankton
- Description: The study undertaken was an attempt to provide information on the effect that oceanographic features common in the Mozambique Channel have on primary production. Oligotrophic conditions dominated the Mozambique Channel at the time of sampling and the introduction of nutrients into the euphotic zone by upwelling processes were identified as cyclonic eddies. Differences in physico-chemical variables between surface and F-max across all sites proved to be stronger than the physico-chemical variables between 4 grouped oceanographic features. This was revealed by stronger variations in phytoplankton community structure and chlorophyll a concentration between surface and F-max compared to oceanographic features sampled. One of the hypotheses presented for the study was that diatoms would dominate phytoplankton communities within a cyclonic eddy. This was not the case as the coccolithophorid, Emiliania huxleyi Lohmann (Hay and Mohler 1967) dominated F-max and surface water in the cyclonic eddies and most other sites. Phytoplankton community structure did not differ significantly between the oceanographic features sampled which contradicted another one of hypotheses presented in the study. Chlorophyll a concentration in surface water of the cyclonic eddies was significantly higher than in surface waters within the anti-cyclonic eddy. F-max was not significantly different in phytoplankton biomass between these two system types. The cyclonic eddies and anti-cyclone had similar phytoplankton diversity which did not verify the hypothesis that there would be less phytoplankton species diversity within cyclonic eddies compared to the anti-cyclonic eddy. Phytoplankton community structure differed between F-max (depth at which maximum chlorophyll a is found) and the surface. This phytoplankton community difference was linked to differences in physico-chemical variables between the two depths. The diatoms Thalassionema nitzschioides, Pseudo-nitzschia sp.A, Pseudo-nitzschia sp.B, Thalassiosira sp.C, Thalassiosira sp.E, Bacteriastrum furcatum, Guinardia cylindrus, Nitzschia closterium, Hemiaulus hauckii, and Nitzschia braarudii revealed the only discernible ecological similarity amongst phytoplankton species across all sites and depths. This is important as it revealed that these species were regularly found occupying similar depths and potentially similar physico-chemical ranges in the water column which suggest these diatom species responded to a dominant source of variation. Distribution patterns of species and of ecologically defined groups support the hypothesis that diatom species and assemblages are good indicators of the changing character of an upwelling system. These statements lead to the assumption that the diatom grouping found in this study indicates areas of upwelling where water temperatures are reduced and nutrients are more readily available. One must keep in mind that ordination techniques are only descriptive and no significance is tested. The coccolithophorid D. anthos and the dinoflagellate Phalacroma spp. were noted as being most dissimilar to all other phytoplankton species with regards to their position in the water column and their response to physico-chemical variables. Finally, the dominance of E. huxleyi in the Mozambique Channel during November/December of 2009 reveals the potential vulnerability of phytoplankton in the channel to ocean acidification.
- Full Text:
- Date Issued: 2012
- Authors: O'Reilly, Bevan James
- Date: 2012
- Subjects: Mozambique Channel. , Phytoplankton
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10622 , http://hdl.handle.net/10948/d1010967 , Mozambique Channel. , Phytoplankton
- Description: The study undertaken was an attempt to provide information on the effect that oceanographic features common in the Mozambique Channel have on primary production. Oligotrophic conditions dominated the Mozambique Channel at the time of sampling and the introduction of nutrients into the euphotic zone by upwelling processes were identified as cyclonic eddies. Differences in physico-chemical variables between surface and F-max across all sites proved to be stronger than the physico-chemical variables between 4 grouped oceanographic features. This was revealed by stronger variations in phytoplankton community structure and chlorophyll a concentration between surface and F-max compared to oceanographic features sampled. One of the hypotheses presented for the study was that diatoms would dominate phytoplankton communities within a cyclonic eddy. This was not the case as the coccolithophorid, Emiliania huxleyi Lohmann (Hay and Mohler 1967) dominated F-max and surface water in the cyclonic eddies and most other sites. Phytoplankton community structure did not differ significantly between the oceanographic features sampled which contradicted another one of hypotheses presented in the study. Chlorophyll a concentration in surface water of the cyclonic eddies was significantly higher than in surface waters within the anti-cyclonic eddy. F-max was not significantly different in phytoplankton biomass between these two system types. The cyclonic eddies and anti-cyclone had similar phytoplankton diversity which did not verify the hypothesis that there would be less phytoplankton species diversity within cyclonic eddies compared to the anti-cyclonic eddy. Phytoplankton community structure differed between F-max (depth at which maximum chlorophyll a is found) and the surface. This phytoplankton community difference was linked to differences in physico-chemical variables between the two depths. The diatoms Thalassionema nitzschioides, Pseudo-nitzschia sp.A, Pseudo-nitzschia sp.B, Thalassiosira sp.C, Thalassiosira sp.E, Bacteriastrum furcatum, Guinardia cylindrus, Nitzschia closterium, Hemiaulus hauckii, and Nitzschia braarudii revealed the only discernible ecological similarity amongst phytoplankton species across all sites and depths. This is important as it revealed that these species were regularly found occupying similar depths and potentially similar physico-chemical ranges in the water column which suggest these diatom species responded to a dominant source of variation. Distribution patterns of species and of ecologically defined groups support the hypothesis that diatom species and assemblages are good indicators of the changing character of an upwelling system. These statements lead to the assumption that the diatom grouping found in this study indicates areas of upwelling where water temperatures are reduced and nutrients are more readily available. One must keep in mind that ordination techniques are only descriptive and no significance is tested. The coccolithophorid D. anthos and the dinoflagellate Phalacroma spp. were noted as being most dissimilar to all other phytoplankton species with regards to their position in the water column and their response to physico-chemical variables. Finally, the dominance of E. huxleyi in the Mozambique Channel during November/December of 2009 reveals the potential vulnerability of phytoplankton in the channel to ocean acidification.
- Full Text:
- Date Issued: 2012
Plantar pressure and impulse profiles of students from a South African university
- Authors: Kramer, Mark
- Date: 2012
- Subjects: Human mechanics , Foot -- Movements , Joints -- ange of motion , eng
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10095 , http://hdl.handle.net/10948/d1010606 , Human mechanics , Foot -- Movements , Joints -- ange of motion
- Description: Most activities of daily living and numerous modes of physical activity incorporate some form of ambulation, of which the foot and ankle constitute the first link in the kinetic chain. A change in foot or ankle structure may therefore have subsequent effects on the superincumbent joints of the human body such as the knee, hip and lower back. Plantar pressure and impulse measurements can therefore provide greater insight into the mechanics of the foot under load-bearing conditions with regards to the areas and regions of the foot that exhibit the largest pressure values and impulse figures. Hence, it is of importance to establish normative data so as to obtain a frame of reference to identify those individuals that fall outside these norms and may exhibit a larger probability of injury. Aim and Objectives: The primary aim was to identify and compare the plantar pressure distribution patterns and impulse values of students of a South African university of different gender and race groups. To realise this aim two specific objectives were set. The first was to determine whether height, weight, body mass index (BMI), gender, race, and the level of physical activity were related to the pressure and impulse values obtained, and the second was to generate reference tables from the normative data gathered. Method: The RS Footscan system was used to measure the pressure and impulse values of the foot. The characteristics that were analysed were height, weight, body mass index and the level of physical activity of the participant and their respective association with plantar pressure and impulse values obtained. This information was then used to establish normative data. A quasi-experimental study design utilising convenience sampling was implemented as the intention was to investigate as single instance in as natural a manner as possible. Convenience sampling was used with predefined inclusion and exclusion criteria. A total of 180 participants were utilised in this study and were subdivided as follows: Gender: Males (n = 90); Females (n = 90); Race: African black (n = 60); white (n = 60) and coloured (n = 60). Each race group therefore comprised of 30 males and 30 females respectively. The anthropometric profile of participants was as follows: Age (S.D.) = 22.21 (S.D. ± 2.93) years; Height (S.D.) = 169.69 (S.D. ± 8.91) cm; Weight (S.D.) = 66.97 (S.D. ± 12.01) kg; BMI (S.D.) = 23.16 (S.D. ± 3.15) kg/m2. Participants were asked to complete a questionnaire prior to testing that would identify all exclusion criteria consisting of: the presence of foot pain or deformity, acute lower extremity trauma, lower extremity surgery, exhibited problems of performance including eye, ear or cognitive impairment, diabetes mellitus or other neurological neuropathy, or the use of walking aids. Anthropometric measurements were then taken for those participants that qualified for the study. Participants were required to perform approximately five warm-up trials to familiarise themselves with the testing equipment before testing commenced. A total of ten successful trails were subsequently recorded for each participant, with three footprints being recorded per trial on the pressure platform, thereby comprising 30 footprints (15 left foot and 15 right foot) per participant that were analysed regarding pressure and impulse values. The two-step gait initiation protocol was implemented which was proven to be a valid and reliable means of assessing gait. Participants were instructed to walk at a comfortable walking speed between 1.19 – 1.60 m/s to ensure conformity between all participants as between-trial gait velocities were proven to be significantly variable. The foot was subdivided into ten anatomical areas focusing on the great toe, lesser toes, metatarsal 1, metatarsal 2, metatarsal 3, metatarsal 4, metatarsal 5, midfoot, medial heel and lateral heel. These ten areas were then grouped into one of three regions, namely the forefoot region (great toe, lesser toes, and all five metatarsal head areas), midfoot region (midfoot area), and rearfoot/heel region (medial and lateral heel areas). Once all relevant data was gathered, corrected and analysed it was used to establish normative data tables pertaining to the various gender and race groups. Results: Of the ten individual pressure and impulse areas, the second and third metatarsal heads demonstrated the highest mean peak pressure and impulse values. Once grouped into one of the three regions, the heel region was ascribed with the largest impulse and pressure values. It was established that statistically and practically significant racial pressure differences were apparent in the left and right forefoot and midfoot regions, with black and coloured individuals yielding the highest values, whereas white participants yielded the lowest. The same was true with regards to impulse figures in that both statistical and practical significant levels were established in the forefoot and midfoot regions. Black and coloured participants exhibited larger impulse values than the white participants. The level of physical activity was found to be associated with both pressure and impulse values over the various regions of the foot. Black individuals that were largely inactive as well as moderately active coloured participants yielded the highest pressure and impulse values, which were found to be statistically and practically significant over the forefoot regions. Conversely, white participants of all physical activity levels as well as coloured participants of both low and high physical activity levels exhibited the lowest pressure values over the forefoot region, which were also found to be statistically and practically significant. The anthropometric variables of height, weight and BMI were found to relate statistically to pressure and impulse values under the various regions of the foot, but none were found to be of any practical significance (r < .30). Conclusion: It was clearly established that both gender and race specific differences existed regarding plantar pressure and impulse values of the normal foot. Plantar pressure and impulse values were also associated with the level of physical activity of the individual, thereby indicating that the level of physical activity could be a contributing factor to altered pressure and impulse values. Anthropometric variables such as height, weight and BMI could not solely account for the variances observed in pressure and impulse. Further research is required to determine whether pressure or impulse values above or below those obtained predispose an individual to injury and to contrast between various activity or sporting codes and the effect of these on plantar pressure and impulse figures. Finally, from the collected data one was able to establish reference tables for the specific gender and race groups for both plantar pressure and impulse values. This enables one to classify individuals based on the pressure and impulse values generated.
- Full Text:
- Date Issued: 2012
- Authors: Kramer, Mark
- Date: 2012
- Subjects: Human mechanics , Foot -- Movements , Joints -- ange of motion , eng
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10095 , http://hdl.handle.net/10948/d1010606 , Human mechanics , Foot -- Movements , Joints -- ange of motion
- Description: Most activities of daily living and numerous modes of physical activity incorporate some form of ambulation, of which the foot and ankle constitute the first link in the kinetic chain. A change in foot or ankle structure may therefore have subsequent effects on the superincumbent joints of the human body such as the knee, hip and lower back. Plantar pressure and impulse measurements can therefore provide greater insight into the mechanics of the foot under load-bearing conditions with regards to the areas and regions of the foot that exhibit the largest pressure values and impulse figures. Hence, it is of importance to establish normative data so as to obtain a frame of reference to identify those individuals that fall outside these norms and may exhibit a larger probability of injury. Aim and Objectives: The primary aim was to identify and compare the plantar pressure distribution patterns and impulse values of students of a South African university of different gender and race groups. To realise this aim two specific objectives were set. The first was to determine whether height, weight, body mass index (BMI), gender, race, and the level of physical activity were related to the pressure and impulse values obtained, and the second was to generate reference tables from the normative data gathered. Method: The RS Footscan system was used to measure the pressure and impulse values of the foot. The characteristics that were analysed were height, weight, body mass index and the level of physical activity of the participant and their respective association with plantar pressure and impulse values obtained. This information was then used to establish normative data. A quasi-experimental study design utilising convenience sampling was implemented as the intention was to investigate as single instance in as natural a manner as possible. Convenience sampling was used with predefined inclusion and exclusion criteria. A total of 180 participants were utilised in this study and were subdivided as follows: Gender: Males (n = 90); Females (n = 90); Race: African black (n = 60); white (n = 60) and coloured (n = 60). Each race group therefore comprised of 30 males and 30 females respectively. The anthropometric profile of participants was as follows: Age (S.D.) = 22.21 (S.D. ± 2.93) years; Height (S.D.) = 169.69 (S.D. ± 8.91) cm; Weight (S.D.) = 66.97 (S.D. ± 12.01) kg; BMI (S.D.) = 23.16 (S.D. ± 3.15) kg/m2. Participants were asked to complete a questionnaire prior to testing that would identify all exclusion criteria consisting of: the presence of foot pain or deformity, acute lower extremity trauma, lower extremity surgery, exhibited problems of performance including eye, ear or cognitive impairment, diabetes mellitus or other neurological neuropathy, or the use of walking aids. Anthropometric measurements were then taken for those participants that qualified for the study. Participants were required to perform approximately five warm-up trials to familiarise themselves with the testing equipment before testing commenced. A total of ten successful trails were subsequently recorded for each participant, with three footprints being recorded per trial on the pressure platform, thereby comprising 30 footprints (15 left foot and 15 right foot) per participant that were analysed regarding pressure and impulse values. The two-step gait initiation protocol was implemented which was proven to be a valid and reliable means of assessing gait. Participants were instructed to walk at a comfortable walking speed between 1.19 – 1.60 m/s to ensure conformity between all participants as between-trial gait velocities were proven to be significantly variable. The foot was subdivided into ten anatomical areas focusing on the great toe, lesser toes, metatarsal 1, metatarsal 2, metatarsal 3, metatarsal 4, metatarsal 5, midfoot, medial heel and lateral heel. These ten areas were then grouped into one of three regions, namely the forefoot region (great toe, lesser toes, and all five metatarsal head areas), midfoot region (midfoot area), and rearfoot/heel region (medial and lateral heel areas). Once all relevant data was gathered, corrected and analysed it was used to establish normative data tables pertaining to the various gender and race groups. Results: Of the ten individual pressure and impulse areas, the second and third metatarsal heads demonstrated the highest mean peak pressure and impulse values. Once grouped into one of the three regions, the heel region was ascribed with the largest impulse and pressure values. It was established that statistically and practically significant racial pressure differences were apparent in the left and right forefoot and midfoot regions, with black and coloured individuals yielding the highest values, whereas white participants yielded the lowest. The same was true with regards to impulse figures in that both statistical and practical significant levels were established in the forefoot and midfoot regions. Black and coloured participants exhibited larger impulse values than the white participants. The level of physical activity was found to be associated with both pressure and impulse values over the various regions of the foot. Black individuals that were largely inactive as well as moderately active coloured participants yielded the highest pressure and impulse values, which were found to be statistically and practically significant over the forefoot regions. Conversely, white participants of all physical activity levels as well as coloured participants of both low and high physical activity levels exhibited the lowest pressure values over the forefoot region, which were also found to be statistically and practically significant. The anthropometric variables of height, weight and BMI were found to relate statistically to pressure and impulse values under the various regions of the foot, but none were found to be of any practical significance (r < .30). Conclusion: It was clearly established that both gender and race specific differences existed regarding plantar pressure and impulse values of the normal foot. Plantar pressure and impulse values were also associated with the level of physical activity of the individual, thereby indicating that the level of physical activity could be a contributing factor to altered pressure and impulse values. Anthropometric variables such as height, weight and BMI could not solely account for the variances observed in pressure and impulse. Further research is required to determine whether pressure or impulse values above or below those obtained predispose an individual to injury and to contrast between various activity or sporting codes and the effect of these on plantar pressure and impulse figures. Finally, from the collected data one was able to establish reference tables for the specific gender and race groups for both plantar pressure and impulse values. This enables one to classify individuals based on the pressure and impulse values generated.
- Full Text:
- Date Issued: 2012
Political parties in South African law
- Authors: Tiry, Zaahira
- Date: 2012
- Subjects: Political parties -- Law and legislation -- South Africa , Politics -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10285 , http://hdl.handle.net/10948/d1012414 , Political parties -- Law and legislation -- South Africa , Politics -- Law and legislation -- South Africa
- Description: This dissertation is a literature study of the legal regime of political parties in post-apartheid South Africa. A constitutional perspective is adopted throughout the study in order to confine the topic to the realm of South African law. Hence, the focus of the study is to identify legal rights contained in chapter two of the Constitution and to also identify other provisions of the Constitution that have a bearing on political parties. As mentioned in the conclusion, section 19 of the Constitution, set the scene for the development of this study. An analysis of the constitutional provisions highlighted in this study, case law and present legislation dealing with political parties reveals that there is a need for comparative research and the adoption of adequate legislation to regulate the functioning of political parties in South Africa. It is submitted that the regulation of parties by statute is required to ensure a just political order whereby the functioning of political parties is in line with the Constitution.
- Full Text:
- Date Issued: 2012
- Authors: Tiry, Zaahira
- Date: 2012
- Subjects: Political parties -- Law and legislation -- South Africa , Politics -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:10285 , http://hdl.handle.net/10948/d1012414 , Political parties -- Law and legislation -- South Africa , Politics -- Law and legislation -- South Africa
- Description: This dissertation is a literature study of the legal regime of political parties in post-apartheid South Africa. A constitutional perspective is adopted throughout the study in order to confine the topic to the realm of South African law. Hence, the focus of the study is to identify legal rights contained in chapter two of the Constitution and to also identify other provisions of the Constitution that have a bearing on political parties. As mentioned in the conclusion, section 19 of the Constitution, set the scene for the development of this study. An analysis of the constitutional provisions highlighted in this study, case law and present legislation dealing with political parties reveals that there is a need for comparative research and the adoption of adequate legislation to regulate the functioning of political parties in South Africa. It is submitted that the regulation of parties by statute is required to ensure a just political order whereby the functioning of political parties is in line with the Constitution.
- Full Text:
- Date Issued: 2012
Population dynamics of the white shark, Carcharodon carcharias, at Mossel Bay, South Africa
- Authors: Ryklief, Rabiah
- Date: 2012
- Subjects: White shark -- South Africa -- Mossel Bay , Sharks -- South Africa -- Mossel Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10717 , http://hdl.handle.net/10948/d1012077 , White shark -- South Africa -- Mossel Bay , Sharks -- South Africa -- Mossel Bay
- Description: Mossel Bay is internationally recognised as one of the centres of abundance of white sharks in South Africa. During 2008 – 2010 there were four sites within the bay i.e. Seal Island, Hartenbos, Kleinbrak and Grootbrak, which were sampled to gain insight into the population dynamics of this species. Currently, life history information on white sharks in this area is limited. This study used a combination of mark-recapture using photographic identification techniques and sight per unit effort methods. Inter-annual, seasonal and spatial patterns in abundance are assessed. The effects of environmental parameters on abundance are also investigated. Photographic identification techniques were employed to identify unique individuals within the sampled population. This modified mark-recapture approach is therefore non-invasive and cost-effective. Open population POPAN parameterization was used to analyse the data in software program MARK. The total population was estimated at 389 sharks (351 – 428; 95 percent CI). Over the three year period, a marginal (yet non-significant) decline in numbers was observed, in terms of both monthly and seasonal population estimates. Sightings per unit effort data were collected during sampling trips. The relative abundance and body size composition of white sharks demonstrated significant spatial and seasonal variation. The highest and lowest relative abundance was observed at Seal Island and Hartenbos, respectively, and is likely attributed to prey availability. Although white sharks were present year-round in Mossel Bay, the highest relative abundance occurred during summer and the lowest relative abundance occurred during spring. White sharks were grouped into three main size classes based on estimated total length (TL): Young of the year (YOY) (125 – 174cm), juvenile (175 – 324cm) and adult (325 – 524cm). YOY white sharks were most prevalent at Grootbrak, with juvenile and adult individuals concentrating at Seal Island. Although most size classes were present throughout the year, seasonal differences were observed. YOY individuals were most abundant in the autumn months, juvenile size-classes appeared to concentrate in the study area during winter, and the adult individuals were most abundant in the spring months. Overall, there was a high concentration of white sharks ranging in size between 175 – 324cm TL, and it was thus hypothesised that Mossel Bay represents an interim nursery or grow out area for white sharks in South Africa. Data collected from 2008 and 2009 was used to investigate the relationship between specific environmental parameters, i.e. sea surface temperature and vertical water clarity, in relation to the relative abundance of white sharks. Sea surface temperature and vertical water clarity observed in this study ranged from 9.3 - 22.7°C and 0 – 10m, respectively. Sea surface temperature did not have a significant influence on the relative abundance of white sharks and this may be attributed to the thermoregulatory capacity of the species. Vertical water clarity, however, did significantly influence the relative abundance. Furthermore, the combined effect of site and season significantly influenced the relative abundance of white sharks and is probably linked to the distribution and abundance of inshore prey resources.
- Full Text:
- Date Issued: 2012
- Authors: Ryklief, Rabiah
- Date: 2012
- Subjects: White shark -- South Africa -- Mossel Bay , Sharks -- South Africa -- Mossel Bay
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10717 , http://hdl.handle.net/10948/d1012077 , White shark -- South Africa -- Mossel Bay , Sharks -- South Africa -- Mossel Bay
- Description: Mossel Bay is internationally recognised as one of the centres of abundance of white sharks in South Africa. During 2008 – 2010 there were four sites within the bay i.e. Seal Island, Hartenbos, Kleinbrak and Grootbrak, which were sampled to gain insight into the population dynamics of this species. Currently, life history information on white sharks in this area is limited. This study used a combination of mark-recapture using photographic identification techniques and sight per unit effort methods. Inter-annual, seasonal and spatial patterns in abundance are assessed. The effects of environmental parameters on abundance are also investigated. Photographic identification techniques were employed to identify unique individuals within the sampled population. This modified mark-recapture approach is therefore non-invasive and cost-effective. Open population POPAN parameterization was used to analyse the data in software program MARK. The total population was estimated at 389 sharks (351 – 428; 95 percent CI). Over the three year period, a marginal (yet non-significant) decline in numbers was observed, in terms of both monthly and seasonal population estimates. Sightings per unit effort data were collected during sampling trips. The relative abundance and body size composition of white sharks demonstrated significant spatial and seasonal variation. The highest and lowest relative abundance was observed at Seal Island and Hartenbos, respectively, and is likely attributed to prey availability. Although white sharks were present year-round in Mossel Bay, the highest relative abundance occurred during summer and the lowest relative abundance occurred during spring. White sharks were grouped into three main size classes based on estimated total length (TL): Young of the year (YOY) (125 – 174cm), juvenile (175 – 324cm) and adult (325 – 524cm). YOY white sharks were most prevalent at Grootbrak, with juvenile and adult individuals concentrating at Seal Island. Although most size classes were present throughout the year, seasonal differences were observed. YOY individuals were most abundant in the autumn months, juvenile size-classes appeared to concentrate in the study area during winter, and the adult individuals were most abundant in the spring months. Overall, there was a high concentration of white sharks ranging in size between 175 – 324cm TL, and it was thus hypothesised that Mossel Bay represents an interim nursery or grow out area for white sharks in South Africa. Data collected from 2008 and 2009 was used to investigate the relationship between specific environmental parameters, i.e. sea surface temperature and vertical water clarity, in relation to the relative abundance of white sharks. Sea surface temperature and vertical water clarity observed in this study ranged from 9.3 - 22.7°C and 0 – 10m, respectively. Sea surface temperature did not have a significant influence on the relative abundance of white sharks and this may be attributed to the thermoregulatory capacity of the species. Vertical water clarity, however, did significantly influence the relative abundance. Furthermore, the combined effect of site and season significantly influenced the relative abundance of white sharks and is probably linked to the distribution and abundance of inshore prey resources.
- Full Text:
- Date Issued: 2012
Population dynamics of the Zuurberg Cycad and the predicted impact of climate change
- Authors: Singh, Karishma
- Date: 2012
- Subjects: Cycads -- South Africa -- Eastern Cape , Encephalartos -- South Africa -- Eastern Cape , Climate change -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10633 , http://hdl.handle.net/10948/d1012857
- Description: Cycads first appeared about 300 million years ago and historical data indicates that they survived fluctuations of global temperature and carbon dioxide concentrations and reached peak abundance during periods where temperature and carbon dioxide concentrations were much higher than the present conditions as well as the predicted increased levels. With Africa being one of the most vulnerable regions to climate change and in the absence of an evaluation of predicted impacts of climate change on cycads, this study aims to contribute to our understanding of responses of Encephalartos longifolius to increased temperature. Encephalartos longifolius (Jacq.) Lehm is an Eastern Cape endemic and like most cycads has been around for millions of years with very little change to its basic structure. Photosynthetic rates showed E.longifolius seedlings have C3 photosynthesis and even under stress they do not switch over to CAM photosynthesis. The photosynthetic rates of seedlings showed a typical C3 -plant type response under elevated carbon dioxide levels. Increased temperatures could be detrimental to the species but coupled with elevated carbon dioxide levels the growth of Encephalartos longifolius are postulated to outweigh the negative impacts of increased temperatures. Whilst climatic conditions in the Eastern Cape might not impact the abundance of Encephalartos longifolius, the species however is declining rapidly to the present near-threatened status. Demographic studies revealed a high percentage of juvenile numbers in the wild; however juvenile plants are impacted on by animals thereby jeopardizing their survival. Adult plants are heavily impacted on by animals; this reduces the probability of new offspring being produced. Cycads are also very slow - growing which is the primary cause of their ruin in the wild. Encephalartos longifolius grows at just over approximately 1 cm per year with growth being more rapid in the juvenile plants. Once juvenile plants reach approximately 60 cm they stop growing in diameter but only get taller. Seed germination is also a very slow process with an optimum temperature of 28°C and a growth medium of at least 50 percent moisture. Regardless of the Eastern Cape predicted to become the hottest province in South Africa as a result of climate change, cycads will be able to adapt to the changing environment and conservation plans should focus on animal and human impacts that are the major force causing decreasing abundance of Encephalartos longifolius in the wild.
- Full Text:
- Date Issued: 2012
- Authors: Singh, Karishma
- Date: 2012
- Subjects: Cycads -- South Africa -- Eastern Cape , Encephalartos -- South Africa -- Eastern Cape , Climate change -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10633 , http://hdl.handle.net/10948/d1012857
- Description: Cycads first appeared about 300 million years ago and historical data indicates that they survived fluctuations of global temperature and carbon dioxide concentrations and reached peak abundance during periods where temperature and carbon dioxide concentrations were much higher than the present conditions as well as the predicted increased levels. With Africa being one of the most vulnerable regions to climate change and in the absence of an evaluation of predicted impacts of climate change on cycads, this study aims to contribute to our understanding of responses of Encephalartos longifolius to increased temperature. Encephalartos longifolius (Jacq.) Lehm is an Eastern Cape endemic and like most cycads has been around for millions of years with very little change to its basic structure. Photosynthetic rates showed E.longifolius seedlings have C3 photosynthesis and even under stress they do not switch over to CAM photosynthesis. The photosynthetic rates of seedlings showed a typical C3 -plant type response under elevated carbon dioxide levels. Increased temperatures could be detrimental to the species but coupled with elevated carbon dioxide levels the growth of Encephalartos longifolius are postulated to outweigh the negative impacts of increased temperatures. Whilst climatic conditions in the Eastern Cape might not impact the abundance of Encephalartos longifolius, the species however is declining rapidly to the present near-threatened status. Demographic studies revealed a high percentage of juvenile numbers in the wild; however juvenile plants are impacted on by animals thereby jeopardizing their survival. Adult plants are heavily impacted on by animals; this reduces the probability of new offspring being produced. Cycads are also very slow - growing which is the primary cause of their ruin in the wild. Encephalartos longifolius grows at just over approximately 1 cm per year with growth being more rapid in the juvenile plants. Once juvenile plants reach approximately 60 cm they stop growing in diameter but only get taller. Seed germination is also a very slow process with an optimum temperature of 28°C and a growth medium of at least 50 percent moisture. Regardless of the Eastern Cape predicted to become the hottest province in South Africa as a result of climate change, cycads will be able to adapt to the changing environment and conservation plans should focus on animal and human impacts that are the major force causing decreasing abundance of Encephalartos longifolius in the wild.
- Full Text:
- Date Issued: 2012
Post occupancy evaluation of an office building : the case of country club estate, Johannesburg
- Matshili, Humbulani Emmanuel
- Authors: Matshili, Humbulani Emmanuel
- Date: 2012
- Subjects: Architectural design -- Evaluation , Offices -- Design , Office buildings -- South Africa -- Johannesburg -- Evaluation , Real property -- South Africa -- Johannesburg
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9703 , http://hdl.handle.net/10948/d1018554
- Description: Most organisations nowadays want to build offices that are cost effective, but at the same time they forget to consider the impact of IEQ on the occupants’ wellbeing and performance. These offices are equipped with air-conditioners, which may impact negatively on performances if not monitored, controlled and maintained. An occupant’s performance may be accelerated or reduced, based on the effectiveness of IEQ in the office buildings. It is imperative that the employer or management create a work environment that is conducive to the occupants’ needs, so that the occupants may be able to improve their work performance that often yields increased productivity. The main aim of the study was to investigate the efficiency of a building’s Indoor Environmental Quality (IEQ) and how it affects workers with regard to productivity. The objectives of the study were: to determine the level of satisfaction of the occupants in terms of the IEQ, evaluate the effects that the current IEQ of the building has on the productivity of the occupants, and proffer solutions to identified problems so that the building performance can be improved, and similar future buildings can be improved upon in terms of IEQ. Post Occupancy Evaluation (POE) was utilised to conduct the evaluation. This will help stakeholders and managements to ensure that past mistakes committed are not repeated in the future buildings. POE analyses IEQ related to Indoor Air Quality (IEQ), thermal comfort, occupant’s satisfaction and occupant performance and productivity. There is a correlation between different indoor parameters of the occupants’ satisfaction, health and productivity at the workplace. For these correlations to complement each other successfully, IEQ factors must be conducive to human wellbeing. Workplace environments are perceived as unsafe and unhygienic. This situation is caused by poor planning of workstations, low indoor air quality, inappropriate lighting in the office, lack of ventilation and insufficient safety measures. In particular, findings of this study demonstrate the low level of occupants’ satisfaction with regard to office buildings in the Country Club Estate, Johannesburg. The results from this study show that POE is perceived to be completely new to occupants of the Country Club Estate. Management or stakeholders have a huge task ahead to address the benefits of implementing POE and to face the consequences if POE is not implemented.
- Full Text:
- Date Issued: 2012
- Authors: Matshili, Humbulani Emmanuel
- Date: 2012
- Subjects: Architectural design -- Evaluation , Offices -- Design , Office buildings -- South Africa -- Johannesburg -- Evaluation , Real property -- South Africa -- Johannesburg
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9703 , http://hdl.handle.net/10948/d1018554
- Description: Most organisations nowadays want to build offices that are cost effective, but at the same time they forget to consider the impact of IEQ on the occupants’ wellbeing and performance. These offices are equipped with air-conditioners, which may impact negatively on performances if not monitored, controlled and maintained. An occupant’s performance may be accelerated or reduced, based on the effectiveness of IEQ in the office buildings. It is imperative that the employer or management create a work environment that is conducive to the occupants’ needs, so that the occupants may be able to improve their work performance that often yields increased productivity. The main aim of the study was to investigate the efficiency of a building’s Indoor Environmental Quality (IEQ) and how it affects workers with regard to productivity. The objectives of the study were: to determine the level of satisfaction of the occupants in terms of the IEQ, evaluate the effects that the current IEQ of the building has on the productivity of the occupants, and proffer solutions to identified problems so that the building performance can be improved, and similar future buildings can be improved upon in terms of IEQ. Post Occupancy Evaluation (POE) was utilised to conduct the evaluation. This will help stakeholders and managements to ensure that past mistakes committed are not repeated in the future buildings. POE analyses IEQ related to Indoor Air Quality (IEQ), thermal comfort, occupant’s satisfaction and occupant performance and productivity. There is a correlation between different indoor parameters of the occupants’ satisfaction, health and productivity at the workplace. For these correlations to complement each other successfully, IEQ factors must be conducive to human wellbeing. Workplace environments are perceived as unsafe and unhygienic. This situation is caused by poor planning of workstations, low indoor air quality, inappropriate lighting in the office, lack of ventilation and insufficient safety measures. In particular, findings of this study demonstrate the low level of occupants’ satisfaction with regard to office buildings in the Country Club Estate, Johannesburg. The results from this study show that POE is perceived to be completely new to occupants of the Country Club Estate. Management or stakeholders have a huge task ahead to address the benefits of implementing POE and to face the consequences if POE is not implemented.
- Full Text:
- Date Issued: 2012
Post-apartheid racial integration in Grahamstown : a time-geographical perspective
- Authors: Irvine, Philippa Margaret
- Date: 2012
- Subjects: Race discrimination -- South Africa -- Eastern Cape Grahamstown (South Africa) -- Race relations Grahamstown (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4845 , http://hdl.handle.net/10962/d1005521
- Description: This research is situated within the context of the post-apartheid era in South Africa, which includes the dominant ideologies and policies that have shaped the urban landscape of the past and present. It investigates the extent and patterns of integration that exist twenty years after the country’s political transition and it uses Grahamstown, a small education and cultural centre in the Eastern Cape Province, as its case study. The investigation incorporates the traditional geographical focus of residential and educational integration, using conventional means of investigation such as segregation indices, dissimilarity indices, percentages and maps. However, in identifying the broader nature of ‘segregation’ and ‘integration’, the study moves beyond these foci and approaches. It adopts the timegeographical framework to reveal the dynamic use of urban space that reflects the lived space of selected individuals from the community of Grahamstown: the extent and patterns of their behavioural integration or spatial linkages. Together, these approaches reveal that Grahamstown is still a city divided by race and, now, class. Schools and residential areas remain tied to the apartheid divisions of race and the white community exists almost entirely within the bounds of apartheid’s blueprint of urban space. Rhodes University, which is located within Grahamstown, has experienced admirable levels of integration within the student body and within the staff as a whole, but not within the staff’s different levels. In essence, where integration has occurred it has been unidirectional with the black community moving into the spaces and institutions formerly reserved for whites. The limited behavioural integration or spatial linkages are shown to be tied to city structure and, within the white group, to perceptions of ‘otherness’ held by the individuals interviewed. While the study shows limited differences in the time-spatial movements between members of different races who are resident in the former white group area, it highlights the differences between those more permanently resident in the city and the temporary educational migrants or students. The study argues that the slow pace of change is related to the nature of South Africa’s democratic transition and its attending political and economic policies.
- Full Text:
- Date Issued: 2012
- Authors: Irvine, Philippa Margaret
- Date: 2012
- Subjects: Race discrimination -- South Africa -- Eastern Cape Grahamstown (South Africa) -- Race relations Grahamstown (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4845 , http://hdl.handle.net/10962/d1005521
- Description: This research is situated within the context of the post-apartheid era in South Africa, which includes the dominant ideologies and policies that have shaped the urban landscape of the past and present. It investigates the extent and patterns of integration that exist twenty years after the country’s political transition and it uses Grahamstown, a small education and cultural centre in the Eastern Cape Province, as its case study. The investigation incorporates the traditional geographical focus of residential and educational integration, using conventional means of investigation such as segregation indices, dissimilarity indices, percentages and maps. However, in identifying the broader nature of ‘segregation’ and ‘integration’, the study moves beyond these foci and approaches. It adopts the timegeographical framework to reveal the dynamic use of urban space that reflects the lived space of selected individuals from the community of Grahamstown: the extent and patterns of their behavioural integration or spatial linkages. Together, these approaches reveal that Grahamstown is still a city divided by race and, now, class. Schools and residential areas remain tied to the apartheid divisions of race and the white community exists almost entirely within the bounds of apartheid’s blueprint of urban space. Rhodes University, which is located within Grahamstown, has experienced admirable levels of integration within the student body and within the staff as a whole, but not within the staff’s different levels. In essence, where integration has occurred it has been unidirectional with the black community moving into the spaces and institutions formerly reserved for whites. The limited behavioural integration or spatial linkages are shown to be tied to city structure and, within the white group, to perceptions of ‘otherness’ held by the individuals interviewed. While the study shows limited differences in the time-spatial movements between members of different races who are resident in the former white group area, it highlights the differences between those more permanently resident in the city and the temporary educational migrants or students. The study argues that the slow pace of change is related to the nature of South Africa’s democratic transition and its attending political and economic policies.
- Full Text:
- Date Issued: 2012
Pre-concentration of heavy metals in aqueous environments using electrospun polymer nanofiber sorbents
- Authors: Darko, Godfred
- Date: 2012
- Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
- Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
- Full Text:
- Date Issued: 2012
- Authors: Darko, Godfred
- Date: 2012
- Subjects: Heavy metals -- Absorption and adsorption -- Research Nanochemistry -- Research Polystyrene -- Research Polyamides -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4337 , http://hdl.handle.net/10962/d1004998
- Description: This thesis presents an alternative approach for pre-concentrating heavy metals in aqueous environments using electro spun polymer nanofiber sorbents. The conditions for electrospinning polyethersulfone, polystyrene, polysulfone and polyamide-6 were optimized. The morphologies and porosities of the electrospun nanofibers were studied using SEM and BET nitrogen gas adsorptions. The nanofibers had mesoporous morphologies with specific surface areas up to 58 m2/g. The electro spun nanofiber sorbents were characterized in terms of their tunability for both uptake and release of heavy metals. The usability of the sorbent was also assessed. The sorbents showed fast adsorption kinetics for heavy metals « 20 min for As, Cu, Ni and Pb) in different aqueous environments. The adsorption characteristics of the sorbents best fitted the Freundlich isotherm and followed the first order kinetics. The efficiencies of adsorption and desorption of heavy metals on both imidazolyl-functionalized polystyrene and amino-functionalized polysulfone sorbents were more than 95% up to the fifth cycle of usage. Reusability improved dramatically (up to 10 runs of usage) when mechanically stable amino-functionalized nylon-6 electro spun nanofibers were used. The capacity of the amino-functionalized nylon-6 sorbent to pre-concentrate heavy metals compared very favourably with those of aqua regia and HN03+H202 digestions especially in less complex matrices. Due to their highly porous nature, the electro spun nanofibers exhibited high adsorption capacities (up to 50 mg/g) for heavy metal ions. The loading capacities achieved with the imidazolyl-functionalized sorbent were higher than those for amino-functionalized mesoporous silica and biomass-based sorbents. The electro spun nanofiber sorbents presents an efficient and cost effective alternative for preconcentrating heavy metals in aqueous environments.
- Full Text:
- Date Issued: 2012
Prevalence, seasonal trends and incidences of cattle tuberculosis and brucellosis in the Cacadu municipality, Eastern Cape, South Africa
- Authors: Nombebe, Thobeka
- Date: 2012
- Subjects: Tuberculosis in cattle -- South Africa -- Eastern Cape , Brucellosis in animals -- South Africa -- Eastern Cape , Dairy farms -- South Africa -- Eastern Cape , Mycobacterium tuberculosis -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Biostatistics and Epidemiology)
- Identifier: vital:11783 , http://hdl.handle.net/10353/d1016200 , Tuberculosis in cattle -- South Africa -- Eastern Cape , Brucellosis in animals -- South Africa -- Eastern Cape , Dairy farms -- South Africa -- Eastern Cape , Mycobacterium tuberculosis -- South Africa -- Eastern Cape
- Description: A cross-sectional study was conducted from February 2011 to August 2012 to investigate the status and identify risk factors for Bovine Tuberculosis (BTB) and cattle Brucellosis. A total of 1277 cattle from 6 selected dairy farms were tested. The farms were purposively selected on suspected risk. Samples were analysed using Rose Bengal Test (RBPT) and Complement Fixation Test (CFT) for Brucellosis and Comparative Intradermal Tuberculin Test (CITT) for BTB. The results revealed the overall prevalence of 1.6% for Brucellosis and no BTB was found. Logistic regression analysis revealed that age of cattle, herd size and number of calves a cow has had significant association with Brucellosis with p-values 0.0071, 0.0490 and 0.000 respectively. The role of location (p>0.05), gender (p>0.05) and breed (p>0.05) in the occurrence of the disease was not statistically significant at α=0.05, although higher rates were obtained in females and Jersey breed. Questionnaires were also administered to 47 individuals a total of 12 females and 35 males. Most respondents were not aware about cattle brucellosis and cattle tuberculosis. Consumption of raw or unpasteurized milk still occurs with 74.75% of respondents revealed.
- Full Text:
- Date Issued: 2012
- Authors: Nombebe, Thobeka
- Date: 2012
- Subjects: Tuberculosis in cattle -- South Africa -- Eastern Cape , Brucellosis in animals -- South Africa -- Eastern Cape , Dairy farms -- South Africa -- Eastern Cape , Mycobacterium tuberculosis -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc (Biostatistics and Epidemiology)
- Identifier: vital:11783 , http://hdl.handle.net/10353/d1016200 , Tuberculosis in cattle -- South Africa -- Eastern Cape , Brucellosis in animals -- South Africa -- Eastern Cape , Dairy farms -- South Africa -- Eastern Cape , Mycobacterium tuberculosis -- South Africa -- Eastern Cape
- Description: A cross-sectional study was conducted from February 2011 to August 2012 to investigate the status and identify risk factors for Bovine Tuberculosis (BTB) and cattle Brucellosis. A total of 1277 cattle from 6 selected dairy farms were tested. The farms were purposively selected on suspected risk. Samples were analysed using Rose Bengal Test (RBPT) and Complement Fixation Test (CFT) for Brucellosis and Comparative Intradermal Tuberculin Test (CITT) for BTB. The results revealed the overall prevalence of 1.6% for Brucellosis and no BTB was found. Logistic regression analysis revealed that age of cattle, herd size and number of calves a cow has had significant association with Brucellosis with p-values 0.0071, 0.0490 and 0.000 respectively. The role of location (p>0.05), gender (p>0.05) and breed (p>0.05) in the occurrence of the disease was not statistically significant at α=0.05, although higher rates were obtained in females and Jersey breed. Questionnaires were also administered to 47 individuals a total of 12 females and 35 males. Most respondents were not aware about cattle brucellosis and cattle tuberculosis. Consumption of raw or unpasteurized milk still occurs with 74.75% of respondents revealed.
- Full Text:
- Date Issued: 2012
Prevention of mother to child transmission (PMTCT) of HIV/AIDS: a review of using PMTCT services in South Africa
- Authors: Jumare, Fadila
- Date: 2012
- Subjects: AIDS (Disease) in pregnancy -- South Africa -- Prevention , AIDS (Disease) -- South Africa -- Prevention , HIV infections -- Transmission -- South Africa , Antiretroviral agents
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9091 , http://hdl.handle.net/10948/d1011508 , AIDS (Disease) in pregnancy -- South Africa -- Prevention , AIDS (Disease) -- South Africa -- Prevention , HIV infections -- Transmission -- South Africa , Antiretroviral agents
- Description: Despite good intentions and commitment from health providers, it is difficult for HIV positive pregnant women to access Prevention of Mother to Child Transmission of HIV (PMTCT) services (Skinner et al 2005:115). The aim of this research was to find out the extent to which socio-economic and cultural factors influence access to and utilization of PMTCT services. It appeared that despite having a legal plan and framework to ensure that PMTCT services are available and free, the realities confronting HIV positive women in South Africa as suggested by the literature contradicted this objective. Inevitably, these contradictions were identified as some of the main factors contributing to lack of access and inadequate utilization of PMTCT services. These factors were identified through a review of fifteen studies selected based on their relevance to the research aim. The findings were presented according to the following themes: Functioning of clinics, adherence to ART, uptake of VCT and infant feeding practices. According to research evidence, the major socio-cultural factors influencing access and utilization of PMTCT services include fear of stigma and discrimination which are related to cultural norms and practices. The socio-economic factors include transport costs, lack of food, medicines and formula milk which are all related to poverty and unemployment. The research also found that health system constraints such as long waiting times in clinics, stock-outs of formula milk, medicines and test kits influenced the utilization of PMTCT services by HIV positive women.
- Full Text:
- Date Issued: 2012
- Authors: Jumare, Fadila
- Date: 2012
- Subjects: AIDS (Disease) in pregnancy -- South Africa -- Prevention , AIDS (Disease) -- South Africa -- Prevention , HIV infections -- Transmission -- South Africa , Antiretroviral agents
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9091 , http://hdl.handle.net/10948/d1011508 , AIDS (Disease) in pregnancy -- South Africa -- Prevention , AIDS (Disease) -- South Africa -- Prevention , HIV infections -- Transmission -- South Africa , Antiretroviral agents
- Description: Despite good intentions and commitment from health providers, it is difficult for HIV positive pregnant women to access Prevention of Mother to Child Transmission of HIV (PMTCT) services (Skinner et al 2005:115). The aim of this research was to find out the extent to which socio-economic and cultural factors influence access to and utilization of PMTCT services. It appeared that despite having a legal plan and framework to ensure that PMTCT services are available and free, the realities confronting HIV positive women in South Africa as suggested by the literature contradicted this objective. Inevitably, these contradictions were identified as some of the main factors contributing to lack of access and inadequate utilization of PMTCT services. These factors were identified through a review of fifteen studies selected based on their relevance to the research aim. The findings were presented according to the following themes: Functioning of clinics, adherence to ART, uptake of VCT and infant feeding practices. According to research evidence, the major socio-cultural factors influencing access and utilization of PMTCT services include fear of stigma and discrimination which are related to cultural norms and practices. The socio-economic factors include transport costs, lack of food, medicines and formula milk which are all related to poverty and unemployment. The research also found that health system constraints such as long waiting times in clinics, stock-outs of formula milk, medicines and test kits influenced the utilization of PMTCT services by HIV positive women.
- Full Text:
- Date Issued: 2012
Primary education and rural community development in King William's Town District
- Authors: Rawana, Yolisa
- Date: 2012
- Subjects: Education, Rural , Community development -- South Africa -- King William's Town , Rural development -- South Africa -- King William's Town
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9054 , http://hdl.handle.net/10948/d1007750 , Education, Rural , Community development -- South Africa -- King William's Town , Rural development -- South Africa -- King William's Town
- Description: The focus of this research was to investigate the lack of access to primary education in King William's Town district in Eastern Cape which is inhibiting rural community development. The aim of the study was to determine whether geographic location have effects on attendance of school, to perceive gender discrepancy in primary education, to investigate what cost as a factor that contributes to a child's access and attendance to a primary education and to make recommendations to improve the situation. The study followed a descriptive research method. Data was collected by studying relevant existing literature. Document analysis was used to analyse the data and recommendations for improvement were made. The findings revealed that the day to day attendance of learners is below what it should be, which lead to dropouts, non-compliance with legislation, inadequate monitoring and evaluation. There is a need to recruit Department officials with a particular level of education, knowledge, understanding and expertise to minimise the chances of failure. Recommendations are finally made to mitigate the problem situation
- Full Text:
- Date Issued: 2012
- Authors: Rawana, Yolisa
- Date: 2012
- Subjects: Education, Rural , Community development -- South Africa -- King William's Town , Rural development -- South Africa -- King William's Town
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9054 , http://hdl.handle.net/10948/d1007750 , Education, Rural , Community development -- South Africa -- King William's Town , Rural development -- South Africa -- King William's Town
- Description: The focus of this research was to investigate the lack of access to primary education in King William's Town district in Eastern Cape which is inhibiting rural community development. The aim of the study was to determine whether geographic location have effects on attendance of school, to perceive gender discrepancy in primary education, to investigate what cost as a factor that contributes to a child's access and attendance to a primary education and to make recommendations to improve the situation. The study followed a descriptive research method. Data was collected by studying relevant existing literature. Document analysis was used to analyse the data and recommendations for improvement were made. The findings revealed that the day to day attendance of learners is below what it should be, which lead to dropouts, non-compliance with legislation, inadequate monitoring and evaluation. There is a need to recruit Department officials with a particular level of education, knowledge, understanding and expertise to minimise the chances of failure. Recommendations are finally made to mitigate the problem situation
- Full Text:
- Date Issued: 2012
Private sector participation in renewable energy: a survey of listed companies in South Africa
- Authors: Eno, Venessa Asik Awo
- Date: 2012
- Subjects: Renewable energy sources -- South Africa , Energy policy -- South Africa , Public-private sector cooperation -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9114 , http://hdl.handle.net/10948/d1015636
- Description: Although renewable energy technology has received much attention over recent years the depletion of known fossil fuel reserves and the volatility of international fuel prices require that society looks beyond the current coal-dominated electricity generation methods. Investment in renewable energy and energy efficiency is important to reduce the negative economic, social and environmental impacts of energy production and consumption in South Africa. Currently, renewable energy contributes relatively little to primary energy and even less to the consumption of commercial energy. The challenge of transforming entire economies is enormous, especially if a country is as fossil-fuel-based and emission-intensive as South Africa. However, as it is already facing climate change impacts in an increasingly carbon constrained world; South Africa must drastically reduce its greenhouse gas emission intensity soon. The South African electricity sector is a vital part of the economy and at the same time contributes most to the emission problem. Transforming this sector is therefore urgently needed. First steps have been taken to enhance energy efficiency and promote renewable energy, but they have failed to have any large-scale effects. The two major barriers to investments in renewable energy technologies are based in the South African energy innovation system and its inherent power structures and in the economics of renewable energy technologies. Subsequently the private sector will have to play a significant role in closing the human resources gap by providing funds and expertise. Furthermore, the creation of employment opportunities and actively promoting structural change in the economy are seen, especially in industrialized countries, as goals that support the promotion of renewable energy. Moreover, with more support and assistance from the government and partnership with the private sector will be of immense help to achieve renewable energy goals.
- Full Text:
- Date Issued: 2012
- Authors: Eno, Venessa Asik Awo
- Date: 2012
- Subjects: Renewable energy sources -- South Africa , Energy policy -- South Africa , Public-private sector cooperation -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9114 , http://hdl.handle.net/10948/d1015636
- Description: Although renewable energy technology has received much attention over recent years the depletion of known fossil fuel reserves and the volatility of international fuel prices require that society looks beyond the current coal-dominated electricity generation methods. Investment in renewable energy and energy efficiency is important to reduce the negative economic, social and environmental impacts of energy production and consumption in South Africa. Currently, renewable energy contributes relatively little to primary energy and even less to the consumption of commercial energy. The challenge of transforming entire economies is enormous, especially if a country is as fossil-fuel-based and emission-intensive as South Africa. However, as it is already facing climate change impacts in an increasingly carbon constrained world; South Africa must drastically reduce its greenhouse gas emission intensity soon. The South African electricity sector is a vital part of the economy and at the same time contributes most to the emission problem. Transforming this sector is therefore urgently needed. First steps have been taken to enhance energy efficiency and promote renewable energy, but they have failed to have any large-scale effects. The two major barriers to investments in renewable energy technologies are based in the South African energy innovation system and its inherent power structures and in the economics of renewable energy technologies. Subsequently the private sector will have to play a significant role in closing the human resources gap by providing funds and expertise. Furthermore, the creation of employment opportunities and actively promoting structural change in the economy are seen, especially in industrialized countries, as goals that support the promotion of renewable energy. Moreover, with more support and assistance from the government and partnership with the private sector will be of immense help to achieve renewable energy goals.
- Full Text:
- Date Issued: 2012
Problems encountered with the implementation of an activity-based costing system
- Authors: Konan, Nangan Christian
- Date: 2012
- Subjects: Managerial accounting , Cost allocation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:8979 , http://hdl.handle.net/10948/d1018653
- Description: The activity-based costing (ABC) system is a cost allocation technique which appears to have many benefits over the traditional costing systems. However, companies that have attempted to implement ABC have encountered various difficulties. Thus, there is a need to investigate the problems faced by companies while implementing ABC. The main objective of this study was to find solutions to overcome the problems encountered by South African companies during the implementation of an activity-based costing system.
- Full Text:
- Date Issued: 2012
- Authors: Konan, Nangan Christian
- Date: 2012
- Subjects: Managerial accounting , Cost allocation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:8979 , http://hdl.handle.net/10948/d1018653
- Description: The activity-based costing (ABC) system is a cost allocation technique which appears to have many benefits over the traditional costing systems. However, companies that have attempted to implement ABC have encountered various difficulties. Thus, there is a need to investigate the problems faced by companies while implementing ABC. The main objective of this study was to find solutions to overcome the problems encountered by South African companies during the implementation of an activity-based costing system.
- Full Text:
- Date Issued: 2012
Productions of high quality wastewater final effluents remain a challenge in the Eastern Cape Province of South Africa
- Authors: Gusha, Siyabulela Stability
- Date: 2012
- Subjects: Water-supply, Rural -- Health aspects -- South Africa , Pathogenic microorganisms -- South Africa -- Eastern Cape , Water-supply, Rural -- South Africa -- Eastern Cape , Effluent quality -- Testing , Sewage disposal plants -- South Africa -- Eastern Cape , Escherichia coli
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11265 , http://hdl.handle.net/10353/489 , Water-supply, Rural -- Health aspects -- South Africa , Pathogenic microorganisms -- South Africa -- Eastern Cape , Water-supply, Rural -- South Africa -- Eastern Cape , Effluent quality -- Testing , Sewage disposal plants -- South Africa -- Eastern Cape , Escherichia coli
- Description: Water is an indispensible and yet a difficult resource to be renewed, thus water scarcity has become one of the major challenges faced worldwide, with the Southern regions of Africa being the most impacted and affected, especially the Eastern Cape Province of South Africa where rural communities depend on receiving waterbodies that are often negatively impacted by wastewater final effluents. This present study was conducted between August and December 2010 to assess the physicochemical and microbial qualities of the final effluents of peri-urban and rural communities based wastewater treatment plants in the Eastern Cape Province. The physicochemical parameters were determined on site and in the laboratory, while bacteriological qualities were determined using culture based techniques. The virological qualities were determined by molecular methods using reverse transcriptase polymerase chain reaction for the target RNA virus and the conventional polymerase chain reaction for the target DNA virus. For both wastewater treatment plants, the physicochemical parameters ranged as follows: chemical oxygen demand (5.95-45 mg/L); total dissolved solids (114.5-187.0 mg/L); salinity (0.12-0.20 psu); temperature (14.2-25.7oC); pH (6.0-7.6); nitrate and nitrites (1.55-6.7 mg/L and 0.023-1.15 mg/L respectively); biological oxygen demand (3.5-7.8 mg/L); turbidity (1.49-6.98 NTU); and chlorine residual (0-2.97 mg/L). Feacal indicator bacteria counts ranged as follows: feacal coliforms (0-1.25×104 cfu/100 ml); total coliforms (0-3.95×104 cfu/100 ml); and enterococci (0-5.0×103 cfu/100 ml). xviii Seventy five percent of the rural community based plant and 80 percent of the peri-urban community based plant were positive for coxsackie A virus, while hepatitis A virus was detected in all the rural community based plant 80 percent of the peri-urban community based plant. This study suggests the need for intervention by appropriate regulatory agencies to ensure regular monitoring of the qualities of final effluents of wastewater treatment facilities in the Eastern Cape Province and ensure compliance to established guidelines.
- Full Text:
- Date Issued: 2012
- Authors: Gusha, Siyabulela Stability
- Date: 2012
- Subjects: Water-supply, Rural -- Health aspects -- South Africa , Pathogenic microorganisms -- South Africa -- Eastern Cape , Water-supply, Rural -- South Africa -- Eastern Cape , Effluent quality -- Testing , Sewage disposal plants -- South Africa -- Eastern Cape , Escherichia coli
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11265 , http://hdl.handle.net/10353/489 , Water-supply, Rural -- Health aspects -- South Africa , Pathogenic microorganisms -- South Africa -- Eastern Cape , Water-supply, Rural -- South Africa -- Eastern Cape , Effluent quality -- Testing , Sewage disposal plants -- South Africa -- Eastern Cape , Escherichia coli
- Description: Water is an indispensible and yet a difficult resource to be renewed, thus water scarcity has become one of the major challenges faced worldwide, with the Southern regions of Africa being the most impacted and affected, especially the Eastern Cape Province of South Africa where rural communities depend on receiving waterbodies that are often negatively impacted by wastewater final effluents. This present study was conducted between August and December 2010 to assess the physicochemical and microbial qualities of the final effluents of peri-urban and rural communities based wastewater treatment plants in the Eastern Cape Province. The physicochemical parameters were determined on site and in the laboratory, while bacteriological qualities were determined using culture based techniques. The virological qualities were determined by molecular methods using reverse transcriptase polymerase chain reaction for the target RNA virus and the conventional polymerase chain reaction for the target DNA virus. For both wastewater treatment plants, the physicochemical parameters ranged as follows: chemical oxygen demand (5.95-45 mg/L); total dissolved solids (114.5-187.0 mg/L); salinity (0.12-0.20 psu); temperature (14.2-25.7oC); pH (6.0-7.6); nitrate and nitrites (1.55-6.7 mg/L and 0.023-1.15 mg/L respectively); biological oxygen demand (3.5-7.8 mg/L); turbidity (1.49-6.98 NTU); and chlorine residual (0-2.97 mg/L). Feacal indicator bacteria counts ranged as follows: feacal coliforms (0-1.25×104 cfu/100 ml); total coliforms (0-3.95×104 cfu/100 ml); and enterococci (0-5.0×103 cfu/100 ml). xviii Seventy five percent of the rural community based plant and 80 percent of the peri-urban community based plant were positive for coxsackie A virus, while hepatitis A virus was detected in all the rural community based plant 80 percent of the peri-urban community based plant. This study suggests the need for intervention by appropriate regulatory agencies to ensure regular monitoring of the qualities of final effluents of wastewater treatment facilities in the Eastern Cape Province and ensure compliance to established guidelines.
- Full Text:
- Date Issued: 2012
Professional women balancing work and motherhood : a study of coping strategies used in balancing this dual role
- Authors: Gunton, Andrea
- Date: 2012
- Subjects: Working mothers -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Role conflict Stress (Psychology) Working mothers -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3143 , http://hdl.handle.net/10962/d1007242
- Description: The aim of this qualitative research study is to develop insights into the dynamics involved in work- family conflict, balance and coping strategies. The study explores the experiences of seven professional women, who are also mothers, employed in professional work positions in Grahamstown. The research is interpretive in nature as it aims to explore the conflicts experienced by the professional mothers in balancing their competing roles. The study focused on the demands that these women face and the coping strategies that these working mothers develop and use, in order to balance their career aspirations as well as their family responsibilities. It set out to explore the women’s perceptions of work- family conflict and the extent to which they experience it, further examining the compromises that the women have had to make and possible feelings of guilt or regret that they may have experienced. The findings indicated that this balance is sensitive to many facilitating and hindering factors. The participants revealed that they experience work- family conflict, and that the experience of it has largely to do with the guilt of not spending enough time with their family. Another significant finding was that the women expressed their coping strategies as being organised; forming a line between work and family life as well as employing domestic workers. The women further stated that there are constant compromises that have to be made to fit in the multiple roles, and that feelings of guilt and/or regret do set in at times.
- Full Text:
- Date Issued: 2012
- Authors: Gunton, Andrea
- Date: 2012
- Subjects: Working mothers -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Role conflict Stress (Psychology) Working mothers -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3143 , http://hdl.handle.net/10962/d1007242
- Description: The aim of this qualitative research study is to develop insights into the dynamics involved in work- family conflict, balance and coping strategies. The study explores the experiences of seven professional women, who are also mothers, employed in professional work positions in Grahamstown. The research is interpretive in nature as it aims to explore the conflicts experienced by the professional mothers in balancing their competing roles. The study focused on the demands that these women face and the coping strategies that these working mothers develop and use, in order to balance their career aspirations as well as their family responsibilities. It set out to explore the women’s perceptions of work- family conflict and the extent to which they experience it, further examining the compromises that the women have had to make and possible feelings of guilt or regret that they may have experienced. The findings indicated that this balance is sensitive to many facilitating and hindering factors. The participants revealed that they experience work- family conflict, and that the experience of it has largely to do with the guilt of not spending enough time with their family. Another significant finding was that the women expressed their coping strategies as being organised; forming a line between work and family life as well as employing domestic workers. The women further stated that there are constant compromises that have to be made to fit in the multiple roles, and that feelings of guilt and/or regret do set in at times.
- Full Text:
- Date Issued: 2012