Spatial and temporal patterns in the hyperbenthic community structure in a permanently open Eastern Cape estuary, South Africa
- Authors: Heyns, Elodie R
- Date: 2010
- Subjects: Sundays Estuary -- South Africa -- Eastern Cape , Groundfishes -- South Africa -- Eatern Cape , Estuaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5768 , http://hdl.handle.net/10962/d1005456
- Description: The spatial and temporal (seasonal and diel) patterns in the hyperbenthic community structure (>500 μm) was investigated in the warm temperate, permanently open Kariega Estuary situated along the south-eastern coastline of South Africa. Spatial and seasonal patterns in the hyperbenthic community structure were assessed monthly at six stations along the length of the estuary over a period of twelve months. Data were collected using a modified hyperbenthic sledge, comprising two super-imposed nets. Physico-chemical data indicate the presence of a constant reverse salinity gradient, with highest salinities measured in the upper reaches and lowest at the mouth of the estuary. Strong seasonal patterns in temperature, dissolved oxygen and total chlorophyll-a (chl-a) concentrations were evident. Total average hyperbenthic densities ranged between 0.04 and 166 ind.m-3 in the lower net and between 0.12 and 225 ind.m-3 in the upper net. Hyperbenthic biomass values ranged between 0.02 and 11.9 mg.dry weight.m-3 in the lower net and between 0.02 and 17.4 mg.dry weight.m-3 in the upper net. A spatial and temporal pattern in total densities was detected with an increase in abundance over the period of September to October 2008 particularly in the middle reaches (Stations 3 and 4). Both the lower and upper nets were numerically dominated by decapods (mainly brachyuran crab zoeae) with the exception of June and July 2008 when mysids (mainly Mesopodopsis wooldridgei) dominated, making up 72.4 ± 58.14% of the total abundance in the lower net. A redundancy analysis (RDA) indicated that 99.2% of the variance in the hyperbenthic community structure could be explained by the first two canonical axes. Axis one, which accounted for 96.8% of the total variation detected in the ordination plot was highly correlated with sedimentary organic content and to a lesser extent the chl-a concentration within the Kariega Estuary. The correlations with the second canonical axis (2.4%) were less obvious, however, salinity and seston concentration were weakly correlated with this axis. Diel variability in the hyperbenthic community structure was assessed during March 2009. Samples were collected during the day and night (n = 6 for each period) using sampling gear described above. Total average hyperbenthic densities during the day (497.9 ± 254.1 ind.m-3) were significantly higher than night-time estimates (129.9 ± 38.5 ind.m-3; p<0.05). There were no significant differences in the average dayand night-time estimates of hyperbenthic biomass (p>0.05). A hierarchical cluster analysis identified two significantly distinct groupings, designated the day and night samples. Results from the SIMPER procedure indicated that the high densities of crab zoeae recorded during the day-time accounted for the majority of the dissimilarity between the day and night groupings (44.7%). In addition, it is apparent that several benthic species, especially from the cumacean and isopod orders, were absent from the hyperbenthos during the day-time and emerged into the water column at night.
- Full Text:
- Date Issued: 2010
- Authors: Heyns, Elodie R
- Date: 2010
- Subjects: Sundays Estuary -- South Africa -- Eastern Cape , Groundfishes -- South Africa -- Eatern Cape , Estuaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5768 , http://hdl.handle.net/10962/d1005456
- Description: The spatial and temporal (seasonal and diel) patterns in the hyperbenthic community structure (>500 μm) was investigated in the warm temperate, permanently open Kariega Estuary situated along the south-eastern coastline of South Africa. Spatial and seasonal patterns in the hyperbenthic community structure were assessed monthly at six stations along the length of the estuary over a period of twelve months. Data were collected using a modified hyperbenthic sledge, comprising two super-imposed nets. Physico-chemical data indicate the presence of a constant reverse salinity gradient, with highest salinities measured in the upper reaches and lowest at the mouth of the estuary. Strong seasonal patterns in temperature, dissolved oxygen and total chlorophyll-a (chl-a) concentrations were evident. Total average hyperbenthic densities ranged between 0.04 and 166 ind.m-3 in the lower net and between 0.12 and 225 ind.m-3 in the upper net. Hyperbenthic biomass values ranged between 0.02 and 11.9 mg.dry weight.m-3 in the lower net and between 0.02 and 17.4 mg.dry weight.m-3 in the upper net. A spatial and temporal pattern in total densities was detected with an increase in abundance over the period of September to October 2008 particularly in the middle reaches (Stations 3 and 4). Both the lower and upper nets were numerically dominated by decapods (mainly brachyuran crab zoeae) with the exception of June and July 2008 when mysids (mainly Mesopodopsis wooldridgei) dominated, making up 72.4 ± 58.14% of the total abundance in the lower net. A redundancy analysis (RDA) indicated that 99.2% of the variance in the hyperbenthic community structure could be explained by the first two canonical axes. Axis one, which accounted for 96.8% of the total variation detected in the ordination plot was highly correlated with sedimentary organic content and to a lesser extent the chl-a concentration within the Kariega Estuary. The correlations with the second canonical axis (2.4%) were less obvious, however, salinity and seston concentration were weakly correlated with this axis. Diel variability in the hyperbenthic community structure was assessed during March 2009. Samples were collected during the day and night (n = 6 for each period) using sampling gear described above. Total average hyperbenthic densities during the day (497.9 ± 254.1 ind.m-3) were significantly higher than night-time estimates (129.9 ± 38.5 ind.m-3; p<0.05). There were no significant differences in the average dayand night-time estimates of hyperbenthic biomass (p>0.05). A hierarchical cluster analysis identified two significantly distinct groupings, designated the day and night samples. Results from the SIMPER procedure indicated that the high densities of crab zoeae recorded during the day-time accounted for the majority of the dissimilarity between the day and night groupings (44.7%). In addition, it is apparent that several benthic species, especially from the cumacean and isopod orders, were absent from the hyperbenthos during the day-time and emerged into the water column at night.
- Full Text:
- Date Issued: 2010
Spatio-temporal dynamics of ichthyoplankton in the Kowie estuary, South Africa
- Authors: Kruger, Michelle
- Date: 2010
- Subjects: Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5319 , http://hdl.handle.net/10962/d1005164 , Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Description: Ichthyoplankton dynamics in the permanently open Kowie Estuary, in the warm temperate region of South Africa was investigated. The composition, abundance, distribution and seasonality of larval fishes were studied over a two year period between 2004 and 2006. Additionally, tidal exchange of ichthyoplankton and the use of frontal zones in the mouth region of the estuary were also explored between 2008 and 2009. Temporal and spatial trends in occurrence of larval fishes within the estuary and associated marina were obtained from data collected seasonally using boat-based plankton netting at 14 sampling stations along the length of the estuary. A total of 11 128 larval fishes were collected, representing 23 families and 38 taxa. Clupeidae and Gobiidae were the dominant fish families, contributing 47.0 % and 24.7 % respectively to the total catch. Estuarine resident species dominated the overall catch (91 %). A notable absence of older stage larvae and early juveniles characterised the artificial channels of the marina and estuary mouth region. This was attributed to the absence of a shallow, marginal water habitat typical of successful estuarine nursery areas. Tidal exchange of larval fishes was investigated in the Kowie Estuary using a new technique. A set of drifting light traps were set repetitively on the ebb and flood tide every second night for two consecutive 14 day periods during the peak estuarine recruitment period. A total of 553 larval fishes were caught during the study, representing nine families and 26 species. Blenniidae and Clupeidae dominated the catches. Family and species occurrence changed with tide state. Species richness (d) and diversity (H’) varied with tide and was highest on flood tides. Estuary-dependent species, such as Omobranchus woodii were more dominant on flood tides, whilst larvae of marine-spawned species, such as Sardinops sagax, were dominant on the ebb tide. Light trap catches yielded a different composition in terms of development stage / size and species, when compared to towed net studies. Towed plankton nets were again used to study the shear fronts that characterise the mouth region of the canalised Kowie Estuary. It was hypothesised that the convergence zone of the front provides feeding opportunities for ichthyoplankton. Ichthyoplankton, zooplankton and phytoplankton was collected from within and immediately outside of the convergence zone during frontal conditions. Species specific distribution trends emerged from this study. Postflexion larvae and early juvenile stages of the estuary dependent Mugilidae were only present in the foam line of the convergence zones. Some known predators of ichthyoplankton were also present in slightly higher numbers in the convergence zone (isopods) while other predators such as mysid shrimps, chaetognaths and cnidarians were more abundant out of the convergence zone. It appears that these zones may provide access to temporary food patches in the lower estuary but will be accompanied by a trade-off with increased isopod predators. The Kowie Estuary is a heavily impacted system and lack of adequate freshwater supply; artificial channelling and pollution ultimately have a negative impact of the success of this system as a nursery area. Rehabilitation of marginal areas in the lower estuary and marina is suggested as remedial action to re-establish the integrity of the nursery function this system could offer.
- Full Text:
- Date Issued: 2010
- Authors: Kruger, Michelle
- Date: 2010
- Subjects: Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5319 , http://hdl.handle.net/10962/d1005164 , Fishes -- Larvae -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred
- Description: Ichthyoplankton dynamics in the permanently open Kowie Estuary, in the warm temperate region of South Africa was investigated. The composition, abundance, distribution and seasonality of larval fishes were studied over a two year period between 2004 and 2006. Additionally, tidal exchange of ichthyoplankton and the use of frontal zones in the mouth region of the estuary were also explored between 2008 and 2009. Temporal and spatial trends in occurrence of larval fishes within the estuary and associated marina were obtained from data collected seasonally using boat-based plankton netting at 14 sampling stations along the length of the estuary. A total of 11 128 larval fishes were collected, representing 23 families and 38 taxa. Clupeidae and Gobiidae were the dominant fish families, contributing 47.0 % and 24.7 % respectively to the total catch. Estuarine resident species dominated the overall catch (91 %). A notable absence of older stage larvae and early juveniles characterised the artificial channels of the marina and estuary mouth region. This was attributed to the absence of a shallow, marginal water habitat typical of successful estuarine nursery areas. Tidal exchange of larval fishes was investigated in the Kowie Estuary using a new technique. A set of drifting light traps were set repetitively on the ebb and flood tide every second night for two consecutive 14 day periods during the peak estuarine recruitment period. A total of 553 larval fishes were caught during the study, representing nine families and 26 species. Blenniidae and Clupeidae dominated the catches. Family and species occurrence changed with tide state. Species richness (d) and diversity (H’) varied with tide and was highest on flood tides. Estuary-dependent species, such as Omobranchus woodii were more dominant on flood tides, whilst larvae of marine-spawned species, such as Sardinops sagax, were dominant on the ebb tide. Light trap catches yielded a different composition in terms of development stage / size and species, when compared to towed net studies. Towed plankton nets were again used to study the shear fronts that characterise the mouth region of the canalised Kowie Estuary. It was hypothesised that the convergence zone of the front provides feeding opportunities for ichthyoplankton. Ichthyoplankton, zooplankton and phytoplankton was collected from within and immediately outside of the convergence zone during frontal conditions. Species specific distribution trends emerged from this study. Postflexion larvae and early juvenile stages of the estuary dependent Mugilidae were only present in the foam line of the convergence zones. Some known predators of ichthyoplankton were also present in slightly higher numbers in the convergence zone (isopods) while other predators such as mysid shrimps, chaetognaths and cnidarians were more abundant out of the convergence zone. It appears that these zones may provide access to temporary food patches in the lower estuary but will be accompanied by a trade-off with increased isopod predators. The Kowie Estuary is a heavily impacted system and lack of adequate freshwater supply; artificial channelling and pollution ultimately have a negative impact of the success of this system as a nursery area. Rehabilitation of marginal areas in the lower estuary and marina is suggested as remedial action to re-establish the integrity of the nursery function this system could offer.
- Full Text:
- Date Issued: 2010
Structure and functioning of fish assemblages in two South African estuaries, with emphasis on the presence and absence of aquatic macrophyte beds
- Authors: Sheppard, Jill Nicole
- Date: 2010
- Subjects: Estuaries -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5321 , http://hdl.handle.net/10962/d1005166 , Estuaries -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape
- Description: Temporarily open/closed estuaries (TOCEs) are the dominant estuary type in South Africa. These systems are often characterized by extensive beds of submerged macrophytes, which form important foraging and shelter habitats for fishes, especially for estuary-dependent fish species such as the Cape stumpnose Rhabdosargus holubi and Cape moony Monodactylus falciformis that are commonly associated with them. A loss of submerged macrophytes from an estuary has been shown to affect the fish community as well as reducing overall system productivity. The TOC East Kleinemonde Estuary, situated in the warm-temperate biogeographic region of South Africa has been subject to an ongoing long-term fish monitoring project since 1995. During the period 1995 to 2002, this estuary contained large beds of the submerged macrophytes Ruppia cirrhosa and Potamogeton pectinatus. However, subsequent to a major flood event in 2003 these macrophytes have been largely absent from this system. The effect of the loss of submerged macrophytes on the East Kleinemonde fish assemblage was investigated through an analysis of seine and gill net catch data. Seine net catches for a 12 year period, encompassing six years of macrophyte presence and six years of macrophyte senescence, revealed changes in the relative abundance of certain fish species. Vegetation-associated species such as R. holubi and M. falciformis decreased in abundance whereas sediment-associated species, especially members of the family Mugilidae, increased in abundance following loss of the macrophytes in this estuary. The critically endangered pipefish Syngnathus watermeyeri was only recorded in catches during years in which macrophyte beds were present. In addition to the analysis of catch data, the importance of macrophytes as a primary energy source for selected estuarine fishes was explored through the analysis of carbon and nitrogen stable isotopes. Prior to conducting these analyses, common methodological practices to address the presence of carbonates and lipids within isotope samples were evaluated. A subset of samples were either acid washed to remove carbonates, or lipids were removed according to the method of Bligh and Dyer (1959) as both of these compounds have been shown to affect stable carbon and nitrogen isotope ratios. The suitability of the lipid normalization models of Fry (2002) and Post et al. (2007) for samples of estuarine fish muscle were also tested. Based on this evaluation both models are suitable for use with estuarine fish muscle tissue, however since neither carbonate nor lipid content of any of the samples used in this study was high all samples were left untreated in the following analysis. Carbon isotope ratios from a wide range of fish species collected from the East Kleinemonde Estuary during the macrophyte-senescent phase were compared with individuals of the same species from the neighbouring West Kleinemonde Estuary (where extensive beds of R. cirrhosa and P. pectinatus were present) and revealed the influence of submerged macrophyte material in the diet of fishes in the latter system. However, it was apparent that these plants are not directly consumed but rather contribute to the detrital pool that forms a food source for most invertebrate and some fish species. The most significant source of carbon for East Kleinemonde fishes during the macrophyte senescent phase appeared to have a more depleted origin; probably from benthic or pelagic microalgae. In conclusion, while the importance of macrophyte beds as shelter and foraging habitats for estuarine fishes are well documented, their role in terms of the structuring and functioning of fish assemblages in TOCEs remains somewhat uncertain. The findings of this study were possibly masked by the resilience of vegetation-associated species to the loss of this habitat, as well as by life history characteristics of species such as R. holubi that allow their numerical dominance despite habitat change. Nonetheless, macrophyte senescence in the East Kleinemonde Estuary resulted in the loss of at least one species and the reduced abundance of vegetation-associated species, probably reflective of reduced food resources and/or increased vulnerability to predation. As a result, beds of submerged macrophytes are an important habitat within TOCEs.
- Full Text:
- Date Issued: 2010
- Authors: Sheppard, Jill Nicole
- Date: 2010
- Subjects: Estuaries -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5321 , http://hdl.handle.net/10962/d1005166 , Estuaries -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape
- Description: Temporarily open/closed estuaries (TOCEs) are the dominant estuary type in South Africa. These systems are often characterized by extensive beds of submerged macrophytes, which form important foraging and shelter habitats for fishes, especially for estuary-dependent fish species such as the Cape stumpnose Rhabdosargus holubi and Cape moony Monodactylus falciformis that are commonly associated with them. A loss of submerged macrophytes from an estuary has been shown to affect the fish community as well as reducing overall system productivity. The TOC East Kleinemonde Estuary, situated in the warm-temperate biogeographic region of South Africa has been subject to an ongoing long-term fish monitoring project since 1995. During the period 1995 to 2002, this estuary contained large beds of the submerged macrophytes Ruppia cirrhosa and Potamogeton pectinatus. However, subsequent to a major flood event in 2003 these macrophytes have been largely absent from this system. The effect of the loss of submerged macrophytes on the East Kleinemonde fish assemblage was investigated through an analysis of seine and gill net catch data. Seine net catches for a 12 year period, encompassing six years of macrophyte presence and six years of macrophyte senescence, revealed changes in the relative abundance of certain fish species. Vegetation-associated species such as R. holubi and M. falciformis decreased in abundance whereas sediment-associated species, especially members of the family Mugilidae, increased in abundance following loss of the macrophytes in this estuary. The critically endangered pipefish Syngnathus watermeyeri was only recorded in catches during years in which macrophyte beds were present. In addition to the analysis of catch data, the importance of macrophytes as a primary energy source for selected estuarine fishes was explored through the analysis of carbon and nitrogen stable isotopes. Prior to conducting these analyses, common methodological practices to address the presence of carbonates and lipids within isotope samples were evaluated. A subset of samples were either acid washed to remove carbonates, or lipids were removed according to the method of Bligh and Dyer (1959) as both of these compounds have been shown to affect stable carbon and nitrogen isotope ratios. The suitability of the lipid normalization models of Fry (2002) and Post et al. (2007) for samples of estuarine fish muscle were also tested. Based on this evaluation both models are suitable for use with estuarine fish muscle tissue, however since neither carbonate nor lipid content of any of the samples used in this study was high all samples were left untreated in the following analysis. Carbon isotope ratios from a wide range of fish species collected from the East Kleinemonde Estuary during the macrophyte-senescent phase were compared with individuals of the same species from the neighbouring West Kleinemonde Estuary (where extensive beds of R. cirrhosa and P. pectinatus were present) and revealed the influence of submerged macrophyte material in the diet of fishes in the latter system. However, it was apparent that these plants are not directly consumed but rather contribute to the detrital pool that forms a food source for most invertebrate and some fish species. The most significant source of carbon for East Kleinemonde fishes during the macrophyte senescent phase appeared to have a more depleted origin; probably from benthic or pelagic microalgae. In conclusion, while the importance of macrophyte beds as shelter and foraging habitats for estuarine fishes are well documented, their role in terms of the structuring and functioning of fish assemblages in TOCEs remains somewhat uncertain. The findings of this study were possibly masked by the resilience of vegetation-associated species to the loss of this habitat, as well as by life history characteristics of species such as R. holubi that allow their numerical dominance despite habitat change. Nonetheless, macrophyte senescence in the East Kleinemonde Estuary resulted in the loss of at least one species and the reduced abundance of vegetation-associated species, probably reflective of reduced food resources and/or increased vulnerability to predation. As a result, beds of submerged macrophytes are an important habitat within TOCEs.
- Full Text:
- Date Issued: 2010
Studies on mixed-species colonies of honeybees, Apis cerana and Apis mellifera
- Authors: Yang, Ming-Xian
- Date: 2010
- Subjects: Bees Apis cerana Honeybee Honeybee -- Behavior Bee culture Honeybee -- Physiology Insect societies Animal communication Bees -- Nests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5779 , http://hdl.handle.net/10962/d1005467
- Description: The honeybees Apis cerana and Apis mellifera are derived from the same ancestral base about two million years ago. With speciation and evolution, they have acquired many advanced living skills in common, but have also evolved very different living strategies due to different distributions. This thesis is an intensive study of the biology of the mixed-species colonies of these species, the aims of which were to investigate their behavioural relationships and uncover the evolutionary conserved features of their behaviours subsequent to speciation. The results show that the two species can form a stable society to perform normal tasks. First, workers of both species in the mixed-colonies could form the typical retinue behaviour to hetero-species queens, thus indicating that queen pheromones could be spread to and by both species. Secondly, both species did not show significantly different ovarian activation under hetero-species queens, suggesting that the queen pheromones more likely play a role of "honest signal" rather than a "repression" substance in the honeybee colonies. Thirdly, both species could mutually decode each other‘s waggle dances, with unexpectedly low misunderstanding; revealing that the dance language in a dark environment is quite adaptive for cavity-nesting honeybees. Fourthly, workers of both species could cooperate with each other in comb construction, although the combs they built contain many irregular cells. Interestingly, A. cerana workers could be stimulated by A. mellifera workers to perform this task, thus confirming self-organization theory in the colony. Fifthly, A. mellifera workers behaved more "defectively" in thermoregulation, but perhaps because A. cerana workers are more sensitive to changes in hive temperature. Given these differences in strategy, A. mellifera workers‘ performance might in fact reduce conflicts. Lastly, when faced with threats of predatory wasps, both species engaged in aggressive defence. Although they did not learn from each other‘s responses, species-specific strategies were adopted by each of them so that the defence of the mixed-colonies is very effective. I conclude that the two species can adapt to each other‘s efforts and task allocation is reasonably organized allowing mixed-species colonies to reach stability. These results suggest that all of the social behaviours discussed here were highly conserved following speciation. This thesis could provide some clues for the study of honeybee evolution from open-nesting to the transition of cavity-nesting.
- Full Text:
- Date Issued: 2010
- Authors: Yang, Ming-Xian
- Date: 2010
- Subjects: Bees Apis cerana Honeybee Honeybee -- Behavior Bee culture Honeybee -- Physiology Insect societies Animal communication Bees -- Nests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5779 , http://hdl.handle.net/10962/d1005467
- Description: The honeybees Apis cerana and Apis mellifera are derived from the same ancestral base about two million years ago. With speciation and evolution, they have acquired many advanced living skills in common, but have also evolved very different living strategies due to different distributions. This thesis is an intensive study of the biology of the mixed-species colonies of these species, the aims of which were to investigate their behavioural relationships and uncover the evolutionary conserved features of their behaviours subsequent to speciation. The results show that the two species can form a stable society to perform normal tasks. First, workers of both species in the mixed-colonies could form the typical retinue behaviour to hetero-species queens, thus indicating that queen pheromones could be spread to and by both species. Secondly, both species did not show significantly different ovarian activation under hetero-species queens, suggesting that the queen pheromones more likely play a role of "honest signal" rather than a "repression" substance in the honeybee colonies. Thirdly, both species could mutually decode each other‘s waggle dances, with unexpectedly low misunderstanding; revealing that the dance language in a dark environment is quite adaptive for cavity-nesting honeybees. Fourthly, workers of both species could cooperate with each other in comb construction, although the combs they built contain many irregular cells. Interestingly, A. cerana workers could be stimulated by A. mellifera workers to perform this task, thus confirming self-organization theory in the colony. Fifthly, A. mellifera workers behaved more "defectively" in thermoregulation, but perhaps because A. cerana workers are more sensitive to changes in hive temperature. Given these differences in strategy, A. mellifera workers‘ performance might in fact reduce conflicts. Lastly, when faced with threats of predatory wasps, both species engaged in aggressive defence. Although they did not learn from each other‘s responses, species-specific strategies were adopted by each of them so that the defence of the mixed-colonies is very effective. I conclude that the two species can adapt to each other‘s efforts and task allocation is reasonably organized allowing mixed-species colonies to reach stability. These results suggest that all of the social behaviours discussed here were highly conserved following speciation. This thesis could provide some clues for the study of honeybee evolution from open-nesting to the transition of cavity-nesting.
- Full Text:
- Date Issued: 2010
Studies towards the development of novel HIV-1 integrase inhibitors
- Authors: Lee, Yi-Chen
- Date: 2010
- Subjects: HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4357 , http://hdl.handle.net/10962/d1005022 , HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Description: The project has focused on the preparation of several series of compounds designed as potential HIV-1 integrase inhibitors. Various 2-nitrobenzaldehydes have been reacted with two activated alkenes, methyl vinyl ketone (MVK) and methyl acrylate, under Baylis-Hillman conditions to afford α-methylene-β-hydroxylalkyl derivatives in moderate to excellent yields. The reactions were conducted using the tertiary amine catalysts, 1,4-diazabicyclo[2.2.2]octane(DABCO) or 3-hydroxyquinuclidine (3-HQ) with chloroform as solvent, and yields were optimised by varying the catalyst, reagent concentrations and the reaction time. Reductive cyclization of the Baylis-Hillman adducts via catalytic hydrogenation, using 10% palladiumon-carbon catalyst in ethanol, afforded quinoline and quinoline N-oxide derivatives. In some cases “acyclic” reduction products were also isolated. Reaction of the Baylis-Hillman MVK adducts with HCl, has resulted in effective nucleophilic (SN’) displacement of the hydroxyl group to afford allylic chloride derivatives. Direct substitution of these chloro derivatives by secondary or primary amines, followed by catalytic hydrogenation gave quinoline derivatives containing a 3-aminomethyl substituent. The Baylis-Hillman ester adducts obtained from reaction with methyl acrylate were treated directly with various amines to give diastereomeric conjugate addition products. Reactions with piperazine gave N,N’-disubstituted piperazine products. The piperidine derivatives have been dehydrated to give cinnamate esters in moderate yields. The products, which have all been satisfactorily characterised by elemental (HRMS) and spectroscopic (1- and 2-D NMR) analysis, constitute a “library” of compounds for in silico and in vitro studies as potential HIV integrase inhibitors.
- Full Text:
- Date Issued: 2010
- Authors: Lee, Yi-Chen
- Date: 2010
- Subjects: HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4357 , http://hdl.handle.net/10962/d1005022 , HIV infections -- Treatment , HIV (Viruses) , AIDS (Disease) -- Treatment , Nuclear magnetic resonance , Heterocyclic compounds -- Derivatives , Enzyme inhibitors , Chemical inhibitors , Quinoline
- Description: The project has focused on the preparation of several series of compounds designed as potential HIV-1 integrase inhibitors. Various 2-nitrobenzaldehydes have been reacted with two activated alkenes, methyl vinyl ketone (MVK) and methyl acrylate, under Baylis-Hillman conditions to afford α-methylene-β-hydroxylalkyl derivatives in moderate to excellent yields. The reactions were conducted using the tertiary amine catalysts, 1,4-diazabicyclo[2.2.2]octane(DABCO) or 3-hydroxyquinuclidine (3-HQ) with chloroform as solvent, and yields were optimised by varying the catalyst, reagent concentrations and the reaction time. Reductive cyclization of the Baylis-Hillman adducts via catalytic hydrogenation, using 10% palladiumon-carbon catalyst in ethanol, afforded quinoline and quinoline N-oxide derivatives. In some cases “acyclic” reduction products were also isolated. Reaction of the Baylis-Hillman MVK adducts with HCl, has resulted in effective nucleophilic (SN’) displacement of the hydroxyl group to afford allylic chloride derivatives. Direct substitution of these chloro derivatives by secondary or primary amines, followed by catalytic hydrogenation gave quinoline derivatives containing a 3-aminomethyl substituent. The Baylis-Hillman ester adducts obtained from reaction with methyl acrylate were treated directly with various amines to give diastereomeric conjugate addition products. Reactions with piperazine gave N,N’-disubstituted piperazine products. The piperidine derivatives have been dehydrated to give cinnamate esters in moderate yields. The products, which have all been satisfactorily characterised by elemental (HRMS) and spectroscopic (1- and 2-D NMR) analysis, constitute a “library” of compounds for in silico and in vitro studies as potential HIV integrase inhibitors.
- Full Text:
- Date Issued: 2010
Take my word for it: a new approach to the problem of sincerity in the epistemology of testimony
- Authors: Dewhurst, Therese
- Date: 2010
- Subjects: Sincerity Philosophy Terminology Knowledge, Theory of Honesty
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2707 , http://hdl.handle.net/10962/d1002837
- Description: The epistemological problem of sincerity in testimony is often approached in the following way: We, as a matter of fact, accept utterances as sincere. We do so in the face of knowledge that people lie and deceive,and yet we still count these beliefs as good beliefs. Therefore there must be some reason or argument that we can cite in order to justify our acceptance of the sincerity of the speaker. In this thesis I will argue, contra this, that there is no reason, per se, that justifies our of a speakers sincerity: this is because recognition of the obligation to accept the sincerity is a necessary condition on the possibility of communication and interpretation. In the first three of the thesis I will argue against three of the main approaches to the problem by focusing on what I believe to be the strongest accounts of each: Elizabeth Fricker's reductionism, Tyler Burge's non-reductionism, and Paul Faulkner's trust account of testimony. In the final chapter I will put forward my positive account. I will argue that it is a constitutive rule of language that a speaker be sincere, and then make the further claim, that it is a constitutive rule of interpretation that the hearer take an utterance as sincere. On my account, successful communication does not just depend on a speaker making sincere utterances,but just as importantly,, on the hearer recognising an obligation to take those utterances as being sincere.
- Full Text:
- Date Issued: 2010
- Authors: Dewhurst, Therese
- Date: 2010
- Subjects: Sincerity Philosophy Terminology Knowledge, Theory of Honesty
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2707 , http://hdl.handle.net/10962/d1002837
- Description: The epistemological problem of sincerity in testimony is often approached in the following way: We, as a matter of fact, accept utterances as sincere. We do so in the face of knowledge that people lie and deceive,and yet we still count these beliefs as good beliefs. Therefore there must be some reason or argument that we can cite in order to justify our acceptance of the sincerity of the speaker. In this thesis I will argue, contra this, that there is no reason, per se, that justifies our of a speakers sincerity: this is because recognition of the obligation to accept the sincerity is a necessary condition on the possibility of communication and interpretation. In the first three of the thesis I will argue against three of the main approaches to the problem by focusing on what I believe to be the strongest accounts of each: Elizabeth Fricker's reductionism, Tyler Burge's non-reductionism, and Paul Faulkner's trust account of testimony. In the final chapter I will put forward my positive account. I will argue that it is a constitutive rule of language that a speaker be sincere, and then make the further claim, that it is a constitutive rule of interpretation that the hearer take an utterance as sincere. On my account, successful communication does not just depend on a speaker making sincere utterances,but just as importantly,, on the hearer recognising an obligation to take those utterances as being sincere.
- Full Text:
- Date Issued: 2010
The advent of the 'Festivore' an exploration of South African audience attendance in the performing arts at the National Arts Festival
- Authors: Antrobus, Richard Roy
- Date: 2010
- Subjects: Standard Bank National Arts Festival -- Economic aspects , Arts -- Economic aspects , Performing arts festivals -- Economic aspects -- South Africa -- Grahamstown , Arts -- South Africa -- Economic aspects , Arts -- South Africa -- Finance , Arts -- South Africa -- Political aspects , Arts audiences -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2130 , http://hdl.handle.net/10962/d1002362
- Description: In South Africa, the performing arts have contributed to enhancing national identity and distinctiveness despite coming up against weak legislation, policy and infrastructure to support their growth and proliferation (Fredericks, 2005: 9). Coupled with a decline in both government and consumer support and the contradictory disparity between valuing the arts and the funding of the arts, theatre companies can no longer rely on the comfort of external subsidies and financial support. In order to be economically viable and sustainable to ensure their survival, there is an increasing demand for theatre companies to look to novel ways of increasing audience demand for theatre and improving audience attendance. However, instead of risking artistic integrity and the performance product to satisfy the market, this research suggests that promotion and development of theatre at arts festivals provides a platform to access a wider theatre-going public, which therefore facilitates a change in the market focus toward appreciation of the product (production). It explores leading arguments pertaining to the attendance of arts and cultural events, namely, Peterson and Simkus (1992), later updated by Peterson‟s (2005)„omnivore-univore‟ argument. The argument purports cultural consumption as binary in nature: either significant and diverse or limited, if not absent altogether. Supported by a number of case-studies, including Chan and Goldthorpe (2005) and Montgomery and Robinson (2008) and Snowball et al. (2009), the investigation challenges Bourdieu‟s (1984) theory on cultural distinction as well as the homology and individualisation argument. In determining the factors that influence cultural taste and consumer behaviour, including motivators and inhibitors of attendance and a predominant emphasis on audience risk and information asymmetry, the research was placed in a local context, providing an overview of the socio-economic theatre environment in South Africa. It investigated the nature, structure and impact of local festivals (as events) in changing audience demand and theatre attendance. With specific reference to the South African National Arts Festival (NAF) the research notes the effects of Hauptfleisch‟s „eventification‟ phenomenon on univore attenders and therefore expands the omnivore-univore theory to include a new breed of attender: the “Festivore”. A case study explored the “Festivore” hypothesis through empirical research, surveys and face-to-face qualitative interviews and on-seat questionnaire responses by festival attenders. Personal interviews and communication was also carried out with leading experts in the field. The data was then analysed using SPSS 13 electronic statistical analysis programme to determine the socio-demographics and the factors that affect theatre attendance of existing, as well as potential target, theatre audiences at the National Arts Festival The study concluded that South African theatre attenders are generally omnivorous consumers and that, more importantly, there seems to be a shift towards „festivorous‟ consumption. Furthermore, evidence supports the development and proliferation of festivals as a means not only to support and promote the arts in South Africa but, more importantly, to generate new theatre audiences and entrench theatre attendance into South African culture.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Richard Roy
- Date: 2010
- Subjects: Standard Bank National Arts Festival -- Economic aspects , Arts -- Economic aspects , Performing arts festivals -- Economic aspects -- South Africa -- Grahamstown , Arts -- South Africa -- Economic aspects , Arts -- South Africa -- Finance , Arts -- South Africa -- Political aspects , Arts audiences -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2130 , http://hdl.handle.net/10962/d1002362
- Description: In South Africa, the performing arts have contributed to enhancing national identity and distinctiveness despite coming up against weak legislation, policy and infrastructure to support their growth and proliferation (Fredericks, 2005: 9). Coupled with a decline in both government and consumer support and the contradictory disparity between valuing the arts and the funding of the arts, theatre companies can no longer rely on the comfort of external subsidies and financial support. In order to be economically viable and sustainable to ensure their survival, there is an increasing demand for theatre companies to look to novel ways of increasing audience demand for theatre and improving audience attendance. However, instead of risking artistic integrity and the performance product to satisfy the market, this research suggests that promotion and development of theatre at arts festivals provides a platform to access a wider theatre-going public, which therefore facilitates a change in the market focus toward appreciation of the product (production). It explores leading arguments pertaining to the attendance of arts and cultural events, namely, Peterson and Simkus (1992), later updated by Peterson‟s (2005)„omnivore-univore‟ argument. The argument purports cultural consumption as binary in nature: either significant and diverse or limited, if not absent altogether. Supported by a number of case-studies, including Chan and Goldthorpe (2005) and Montgomery and Robinson (2008) and Snowball et al. (2009), the investigation challenges Bourdieu‟s (1984) theory on cultural distinction as well as the homology and individualisation argument. In determining the factors that influence cultural taste and consumer behaviour, including motivators and inhibitors of attendance and a predominant emphasis on audience risk and information asymmetry, the research was placed in a local context, providing an overview of the socio-economic theatre environment in South Africa. It investigated the nature, structure and impact of local festivals (as events) in changing audience demand and theatre attendance. With specific reference to the South African National Arts Festival (NAF) the research notes the effects of Hauptfleisch‟s „eventification‟ phenomenon on univore attenders and therefore expands the omnivore-univore theory to include a new breed of attender: the “Festivore”. A case study explored the “Festivore” hypothesis through empirical research, surveys and face-to-face qualitative interviews and on-seat questionnaire responses by festival attenders. Personal interviews and communication was also carried out with leading experts in the field. The data was then analysed using SPSS 13 electronic statistical analysis programme to determine the socio-demographics and the factors that affect theatre attendance of existing, as well as potential target, theatre audiences at the National Arts Festival The study concluded that South African theatre attenders are generally omnivorous consumers and that, more importantly, there seems to be a shift towards „festivorous‟ consumption. Furthermore, evidence supports the development and proliferation of festivals as a means not only to support and promote the arts in South Africa but, more importantly, to generate new theatre audiences and entrench theatre attendance into South African culture.
- Full Text:
- Date Issued: 2010
The biology of austroglanis gilli and austroglanis barnardi (siluriformes : austroglanididae) in the Olifants River system, South Africa
- Authors: Mthombeni, Vusi Gedla
- Date: 2010
- Subjects: Catfishes -- South Africa -- Olifants River , Fishes -- South Africa -- Olifants River -- Growth , Freshwater fishes -- Effect of pesticides on -- South Africa -- Olifants River
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5370 , http://hdl.handle.net/10962/d1015222
- Description: Austroglanis gilli and A. barnardi are endemic to the Clanwilliam-Olifants System in the Western Cape, South Africa. The populations of each of these species are considered to be threatened by various anthropogenic activities, which include inappropriate agricultural practice and impacts of alien invasive fish species. The purpose of this thesis was to assess the life-history of these two endangered species in order to contribute to understanding their biology. Such information is vital for the development of strategies for their conservation. Marginal zone and marginal increment analyses from sectioned lapilliar otoliths of both A. gilli and A. barnardi showed a unimodal peak, suggesting a single annulus formation. The oldest specimens of A. gilli and A. barnardi were 12+ and 14+ years, respectively. The growth of A. gilli and A. barnardi was relatively slow and was best described by the von Bertalanffy growth curve as: L, = 131.56(1 - exp(- 0.27(t - 1.18 ))) for male and L, = 113.86(1 - exp(- 0.43(1- 0.74))) for female A. gilli from the Rondegat River. In the Noordhoeks River, growth was L, = 99.67(1 - exp(- 0.53(t - 0.35))) for male and L, = 96.60(1 - exp(- 0.64(t - 0.11 ))) for female A. gilli, and L, =71.02(1-exp(-0.26(1-3.07))) and L, = 69.50(1-exp(-0.36(1 - 1.88))) for male and female A. barnardi, respectively. The average natural mortality for the combined sexes was estimated using catch curve analysis at 0.37 ± 0.12 per year for A. gilli from the Rondegat River, and at 0.71 ± 0.05 and 0.39 ± 0.04 per year for A. gilli and A. barnardi from the Noordhoeks River, respectively. For A. gilli in the Rondegat River, the first maturity was estimated at 3.3 years (97.3 mm SL) for males and 3.1 years (94.3 mm SL) for females. In the Noordhoeks River, the first maturity for A. gilli was estimated at 2.0 years (71.9 mm SL) for males and 1.7 (66.4 mm SL) for females, and for A. barnardi at 2.0 (55.0 nun SL) for males and 2.9 years (58.9 mm SL) for females. Maturity corresponded closely to the asymptotic sizes from the von Bertalanffy curves, suggesting a shift in energy use from somatic growth to gonad development. Macroscopic assessment of the state of gonads, the Ganado-somatic index and histological examinations revealed that both A. gilli and A. barnardi have a single spawning season. The presence of oocytes in different stages of development in each of the ovaries of mature females collected between November and January suggested asynchronous, iteroperous serial spawning. The resorption of yolk was observed from ovaries collected between February and March and no vitellogenic oocyte was visible from ovaries collected between April and August. A similar trend was observed for males, with spermatozoa filling the lumen between November and January and some residual spermatozoa being present in the lumens soon after the breeding season. Spermatocytes and spermatids were dominant in the testes until October. An Index of Relative Importance revealed that A. gilli feeds predominantly on the benthic macroinvertebrate larvae of Ephemeroptera (particularly Baetidae), Diptera (particularly Chironomidae and Simuliidae) and Trichoptera. Austroglanis barnardi feeds predominantly on dipteran larvae (particularly Chironornidae and Simuliidae). Chi square contingency tables showed a significant difference in the dominant prey items of A. gilli and A. barnardi in the Noordhoeks River (X₂= 53.79, d.f. = 4, p > 0.001) and A. gilli between Rondegat and Noordhoeks rivers (x₂ = 34.74, d.f. = 4, p > 0.001). The Spearman's rank correlation test showed no shifts in the diet of A. barnardi from Noordhoeks River and A. gilli from Rondegat River with a change in size and season (p>O.OS). However, there was a shift in the diet of A. gilli from the Noordhoeks River which could suggest a distinct patchiness of benthic macroinvertebrates between the riffle feeding areas used by juveniles and other biotopes used by adults. The occurrence, in stomach contents, of other prey items from a wide variety of taxa and the presence of allochthonous material from the terrestrial environment could suggest an opportunistic feeding guild for both Austroglanis species. The life-history traits of A. gilli and A. barnardi, which are charaterized by slow growth, long life span and low relative fecundity, indicate that both species are relatively precocial and K-selected. The population of a precocial species is relatively stable and if population numbers were to be greatly reduced, they would require a long time to rebuild. An urgent conservation intervention is therefore recommended for Austroglanis spp. so as to maintain the diversity of populations within these species. The creation of protected river reserves and raising public conservation awareness may minimise activities that result in altered river hydrology and the destruction of complex benthic habitats.
- Full Text:
- Date Issued: 2010
- Authors: Mthombeni, Vusi Gedla
- Date: 2010
- Subjects: Catfishes -- South Africa -- Olifants River , Fishes -- South Africa -- Olifants River -- Growth , Freshwater fishes -- Effect of pesticides on -- South Africa -- Olifants River
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5370 , http://hdl.handle.net/10962/d1015222
- Description: Austroglanis gilli and A. barnardi are endemic to the Clanwilliam-Olifants System in the Western Cape, South Africa. The populations of each of these species are considered to be threatened by various anthropogenic activities, which include inappropriate agricultural practice and impacts of alien invasive fish species. The purpose of this thesis was to assess the life-history of these two endangered species in order to contribute to understanding their biology. Such information is vital for the development of strategies for their conservation. Marginal zone and marginal increment analyses from sectioned lapilliar otoliths of both A. gilli and A. barnardi showed a unimodal peak, suggesting a single annulus formation. The oldest specimens of A. gilli and A. barnardi were 12+ and 14+ years, respectively. The growth of A. gilli and A. barnardi was relatively slow and was best described by the von Bertalanffy growth curve as: L, = 131.56(1 - exp(- 0.27(t - 1.18 ))) for male and L, = 113.86(1 - exp(- 0.43(1- 0.74))) for female A. gilli from the Rondegat River. In the Noordhoeks River, growth was L, = 99.67(1 - exp(- 0.53(t - 0.35))) for male and L, = 96.60(1 - exp(- 0.64(t - 0.11 ))) for female A. gilli, and L, =71.02(1-exp(-0.26(1-3.07))) and L, = 69.50(1-exp(-0.36(1 - 1.88))) for male and female A. barnardi, respectively. The average natural mortality for the combined sexes was estimated using catch curve analysis at 0.37 ± 0.12 per year for A. gilli from the Rondegat River, and at 0.71 ± 0.05 and 0.39 ± 0.04 per year for A. gilli and A. barnardi from the Noordhoeks River, respectively. For A. gilli in the Rondegat River, the first maturity was estimated at 3.3 years (97.3 mm SL) for males and 3.1 years (94.3 mm SL) for females. In the Noordhoeks River, the first maturity for A. gilli was estimated at 2.0 years (71.9 mm SL) for males and 1.7 (66.4 mm SL) for females, and for A. barnardi at 2.0 (55.0 nun SL) for males and 2.9 years (58.9 mm SL) for females. Maturity corresponded closely to the asymptotic sizes from the von Bertalanffy curves, suggesting a shift in energy use from somatic growth to gonad development. Macroscopic assessment of the state of gonads, the Ganado-somatic index and histological examinations revealed that both A. gilli and A. barnardi have a single spawning season. The presence of oocytes in different stages of development in each of the ovaries of mature females collected between November and January suggested asynchronous, iteroperous serial spawning. The resorption of yolk was observed from ovaries collected between February and March and no vitellogenic oocyte was visible from ovaries collected between April and August. A similar trend was observed for males, with spermatozoa filling the lumen between November and January and some residual spermatozoa being present in the lumens soon after the breeding season. Spermatocytes and spermatids were dominant in the testes until October. An Index of Relative Importance revealed that A. gilli feeds predominantly on the benthic macroinvertebrate larvae of Ephemeroptera (particularly Baetidae), Diptera (particularly Chironomidae and Simuliidae) and Trichoptera. Austroglanis barnardi feeds predominantly on dipteran larvae (particularly Chironornidae and Simuliidae). Chi square contingency tables showed a significant difference in the dominant prey items of A. gilli and A. barnardi in the Noordhoeks River (X₂= 53.79, d.f. = 4, p > 0.001) and A. gilli between Rondegat and Noordhoeks rivers (x₂ = 34.74, d.f. = 4, p > 0.001). The Spearman's rank correlation test showed no shifts in the diet of A. barnardi from Noordhoeks River and A. gilli from Rondegat River with a change in size and season (p>O.OS). However, there was a shift in the diet of A. gilli from the Noordhoeks River which could suggest a distinct patchiness of benthic macroinvertebrates between the riffle feeding areas used by juveniles and other biotopes used by adults. The occurrence, in stomach contents, of other prey items from a wide variety of taxa and the presence of allochthonous material from the terrestrial environment could suggest an opportunistic feeding guild for both Austroglanis species. The life-history traits of A. gilli and A. barnardi, which are charaterized by slow growth, long life span and low relative fecundity, indicate that both species are relatively precocial and K-selected. The population of a precocial species is relatively stable and if population numbers were to be greatly reduced, they would require a long time to rebuild. An urgent conservation intervention is therefore recommended for Austroglanis spp. so as to maintain the diversity of populations within these species. The creation of protected river reserves and raising public conservation awareness may minimise activities that result in altered river hydrology and the destruction of complex benthic habitats.
- Full Text:
- Date Issued: 2010
The biotechnology of hard coal utilization as a bioprocess substrate
- Mutambanengwe, Cecil Clifford Zvandada
- Authors: Mutambanengwe, Cecil Clifford Zvandada
- Date: 2010
- Subjects: Coal -- Biotechnology Acid mine drainage Coal mines and mining -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3934 , http://hdl.handle.net/10962/d1003993
- Description: The development of coal biotechnology, using hard coal as a substrate, has been impeded by its low reactivity in biological processes. As a result, the more successful application studies have focused on lignitic soft coals. However, new studies have reported using biologically or geologically oxidized hard coal as a functional substrate option for bioprocess applications on a large scale. This study undertook a preliminary investigation into the feasibility of environmental applications of coal biotechnology using oxidized hard coal substrates in both anaerobic and aerobic processes with carbon dioxide, sulfate and oxygen as terminal electron acceptors. A preliminary characterization of the oxidized hard coal substrates was undertaken to determine and predict their viability and behavior as electron donors and carbon sources for environmental bioprocess applications of direct interest to the coal mining industry. Both biologically and geologically oxidized coal substrates showed loss of up to 17% and 52% carbon respectively and incorporation of oxygen ranging from 0.9 – 24%. The latter substrate showed greater loss of carbon and increased oxygenation. The biologically and geologically oxidized hard coal substrates were shown to partition readily into 23% and 32% organic humic acid, a 0.1% fulvic acid fraction and 65% and 59% inorganic and humin fractions respectively. These organic components were shown to be potentially available for biological consumption. In the unmodified hard coal substrate, partitioning was not observed and it did not perform as a functional substrate for any of the bioprocesses investigated. Where carbon dioxide was used as a terminal electron acceptor, methane production ranging from 9 – 26 mg CH4.g substrate-1 was demonstrated from both oxidized coal substrates. Geologically oxidized coal produced 30% more methane than biologically oxidized coal. Methane yields from the geologically oxidized coal in the presence and absence of a co-substrate were 5 – 13-fold higher than previous studies that used hard coal for methanogenesis. Based on these results, and that the development and optimization of the biological oxidation process is currently ongoing, further applications investigated in this study were undertaken using geologically oxidized coal. It was shown using pyrolysis gas chromatography mass spectrometry that the methanogenic system was dependent on the presence of an effective co-substrate supporting the breakdown of the complex organic structures within the oxidized hard coal substrate. Also that the accumulation of aromatic intermediate breakdown compounds predominantly including toluene, furfural, styrene and 2-methoxy vinyl phenol appeared to become inhibitory to both methanogenic and sulfidogenic reactions. This was shown to be a more likely cause of reactor failure rather than substrate exhaustion over time. Evidence of a reductive degradation pathway of the complex organic structures within the oxidized hard coal substrates was shown through the production, accumulation and utilization of volatile fatty acids including acetic, formic, propionic, butyric and valeric acids. Comparative analysis of the volatile fatty acids produced in this system showed that geologically oxidized coal produced 20% more of the volatile fatty acids profiled and double the total concentration compared to the biologically oxidized coal. The use of geologically oxidized hard coal as a functional substrate for biological sulfate reduction was demonstrated in the neutralization of a simulated acid mine drainage wastewater in both batch and continuous process operations. Results showed an increase in pH from pH 4.0 to ~ pH 8.0 with sulfide production rates of ~ 86 mgL-1.day-1 in the batch reactions, while the pH increased to pH 9.0 and sulfide production rates of up to 450 mgL-1.day-1 were measured in the continuous process studies using sand and coal up-flow packed bed reactors. Again, the requirement for an effective co-substrate was demonstrated with lactate shown to function as a true co-substrate in this system. However, a low cost alternative to lactate would need to emerge if the process was to function in large-scale commercial environmental treatment applications. In this regard, the aerobic growth and production of Neosartorya fischeri biomass (0.64 g.biomass.g SOC-1) was demonstrated using oxidized hard coal and glutamate as a co-substrate. Both can be produced from wastes generated on coal mines, with the fungal biomass generated in potentially large volumes. Preliminary demonstration of the use of the fungal biomass as a carbon and electron donor source for biological sulfate reduction was shown and thus that this could serve as an effective substrate for anaerobic environmental treatment processes. Based on these findings, an Integrated Coal Bioprocess model was proposed using oxidized hard coal as a substrate for environmental remediation applications on coal mines. In this approach, potential applications included methane recovery from waste coal, use of waste coal in the treatment of acid mine drainage waste waters and the recovery and use of humic acids in the rehabilitation of open cast mining soils. This study provided a first report demonstrating the use of biologically and geologically oxidized hard coals as bioprocess substrates in environmental bioremediation applications. It also provided an indication that follow-up bioengineering studies to investigate scaled-up applications of these findings would be warranted.
- Full Text:
- Date Issued: 2010
- Authors: Mutambanengwe, Cecil Clifford Zvandada
- Date: 2010
- Subjects: Coal -- Biotechnology Acid mine drainage Coal mines and mining -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3934 , http://hdl.handle.net/10962/d1003993
- Description: The development of coal biotechnology, using hard coal as a substrate, has been impeded by its low reactivity in biological processes. As a result, the more successful application studies have focused on lignitic soft coals. However, new studies have reported using biologically or geologically oxidized hard coal as a functional substrate option for bioprocess applications on a large scale. This study undertook a preliminary investigation into the feasibility of environmental applications of coal biotechnology using oxidized hard coal substrates in both anaerobic and aerobic processes with carbon dioxide, sulfate and oxygen as terminal electron acceptors. A preliminary characterization of the oxidized hard coal substrates was undertaken to determine and predict their viability and behavior as electron donors and carbon sources for environmental bioprocess applications of direct interest to the coal mining industry. Both biologically and geologically oxidized coal substrates showed loss of up to 17% and 52% carbon respectively and incorporation of oxygen ranging from 0.9 – 24%. The latter substrate showed greater loss of carbon and increased oxygenation. The biologically and geologically oxidized hard coal substrates were shown to partition readily into 23% and 32% organic humic acid, a 0.1% fulvic acid fraction and 65% and 59% inorganic and humin fractions respectively. These organic components were shown to be potentially available for biological consumption. In the unmodified hard coal substrate, partitioning was not observed and it did not perform as a functional substrate for any of the bioprocesses investigated. Where carbon dioxide was used as a terminal electron acceptor, methane production ranging from 9 – 26 mg CH4.g substrate-1 was demonstrated from both oxidized coal substrates. Geologically oxidized coal produced 30% more methane than biologically oxidized coal. Methane yields from the geologically oxidized coal in the presence and absence of a co-substrate were 5 – 13-fold higher than previous studies that used hard coal for methanogenesis. Based on these results, and that the development and optimization of the biological oxidation process is currently ongoing, further applications investigated in this study were undertaken using geologically oxidized coal. It was shown using pyrolysis gas chromatography mass spectrometry that the methanogenic system was dependent on the presence of an effective co-substrate supporting the breakdown of the complex organic structures within the oxidized hard coal substrate. Also that the accumulation of aromatic intermediate breakdown compounds predominantly including toluene, furfural, styrene and 2-methoxy vinyl phenol appeared to become inhibitory to both methanogenic and sulfidogenic reactions. This was shown to be a more likely cause of reactor failure rather than substrate exhaustion over time. Evidence of a reductive degradation pathway of the complex organic structures within the oxidized hard coal substrates was shown through the production, accumulation and utilization of volatile fatty acids including acetic, formic, propionic, butyric and valeric acids. Comparative analysis of the volatile fatty acids produced in this system showed that geologically oxidized coal produced 20% more of the volatile fatty acids profiled and double the total concentration compared to the biologically oxidized coal. The use of geologically oxidized hard coal as a functional substrate for biological sulfate reduction was demonstrated in the neutralization of a simulated acid mine drainage wastewater in both batch and continuous process operations. Results showed an increase in pH from pH 4.0 to ~ pH 8.0 with sulfide production rates of ~ 86 mgL-1.day-1 in the batch reactions, while the pH increased to pH 9.0 and sulfide production rates of up to 450 mgL-1.day-1 were measured in the continuous process studies using sand and coal up-flow packed bed reactors. Again, the requirement for an effective co-substrate was demonstrated with lactate shown to function as a true co-substrate in this system. However, a low cost alternative to lactate would need to emerge if the process was to function in large-scale commercial environmental treatment applications. In this regard, the aerobic growth and production of Neosartorya fischeri biomass (0.64 g.biomass.g SOC-1) was demonstrated using oxidized hard coal and glutamate as a co-substrate. Both can be produced from wastes generated on coal mines, with the fungal biomass generated in potentially large volumes. Preliminary demonstration of the use of the fungal biomass as a carbon and electron donor source for biological sulfate reduction was shown and thus that this could serve as an effective substrate for anaerobic environmental treatment processes. Based on these findings, an Integrated Coal Bioprocess model was proposed using oxidized hard coal as a substrate for environmental remediation applications on coal mines. In this approach, potential applications included methane recovery from waste coal, use of waste coal in the treatment of acid mine drainage waste waters and the recovery and use of humic acids in the rehabilitation of open cast mining soils. This study provided a first report demonstrating the use of biologically and geologically oxidized hard coals as bioprocess substrates in environmental bioremediation applications. It also provided an indication that follow-up bioengineering studies to investigate scaled-up applications of these findings would be warranted.
- Full Text:
- Date Issued: 2010
The characterisation of trypanosomal type 1 DnaJ-like proteins
- Authors: Ludewig, Michael Hans
- Date: 2010
- Subjects: Molecular genetics , Molecular chaperones , Protozoa , Heat shock proteins , Trypanosoma
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4126 , http://hdl.handle.net/10962/d1015205
- Description: Trypanosomes are protozoans, of which many are parasitic, and possess complex lifecycles which alternate between mammalian and arthropod hosts. As is the case with most organisms, molecular chaperones and heat shock proteins are encoded within the genomes of these protozoans. These proteins are an integral part of maintaining the structural integrity of proteins during normal and stress conditions. Heat shock protein 40 (Hsp40) is a co-chaperone of heat shock protein 70 (Hsp70) and in some cases can act as a chaperone. These proteins work together to bind non-native polypeptide structures to prevent unfolded protein aggregrate formation in times of stress, translocate proteins across organelle membranes, and transport unsalvageable proteins to proteolytic degradation by the cellular proteasome. Hsp40s are divided into four types based on their domain structure. Analysis of the nuclear genomes of eight trypanosomatid species revealed that less than 10 of the approximate 70 Hsp40 sequences per genome were Type 1 Hsp40s, many of which contained putative orthologues in the other seven trypanosomatid genomes. One of these Type 1 Hsp40s from T b. brucei, Trypanosoma brucei DnaJ 2 (Tbj2), was functionally characterised in T brucei brucei. RNA interference knockdown of expression in T brucei brucei showed that cells deficient in Tbj2 displayed a severe inhibition of the growth of the cell population. The levels of the Tbj2 protein population in T brucei brucei cells increases after exposure to 42°c and the protein was found to have a generalized cytoplasmic subcellular localization at 37°c. These findings provide evidence that Tbj2 is an orthologue of Yeast DnaJ 1 (Y dj l), an essential S. cerevisiae protein. Hsp40s interact with their partner Hsp70s through their J-domain. The amino acids of the J-domain important for a functional interaction with Hsp70 were examined in Trypanosoma cruzi DnaJ 2 (Tcj2) (the orthologue of Tbj2) and T cruzi DnaJ protein 3 (Tcj3) by testing their ability to substitute for Y dj l in Saccharomyces cerevisae and for DnaJ in Escherichia coli. In both systems, the positively charged amino acids of Helix II and III of the J-domain disrupted the functional interaction of these Hsp40s with their partner Hsp70s. Substitutions in Helix I and IV of the J-domains of Tcj2 and Tcj3 produced varied results in the two different systems, possibly suggesting that these helices serve to define with which Hsp70s a given Hsp40 can interact. The inability of an Hsp40 and an Hsp70 to interact functionally does not necessarily mean a total absence of physical interaction between these proteins. The amino acid substitution of the histidine in the HPD motif (H34Q) of the J-domain of Tcj2 and Tcj3 removed the ability of these proteins to interact functionally with S. cerevisiae Hsp70 (Ssal) in vivo. However, preliminary binding studies using the quartz crystal microbalance with dissipation monitoring (QCM-D) show that Tcj2 and Tcj2(H34Q) both physically interact with M sativa Hsp70 in vitro. This study is the first report to provide evidence that certain trypanosoma! Type 1 Hsp40s are essential proteins. Futhermore, the interaction of these Hsp40s with Hsp70 identified important features of the functional interface of this chaperone machinery.
- Full Text:
- Date Issued: 2010
- Authors: Ludewig, Michael Hans
- Date: 2010
- Subjects: Molecular genetics , Molecular chaperones , Protozoa , Heat shock proteins , Trypanosoma
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4126 , http://hdl.handle.net/10962/d1015205
- Description: Trypanosomes are protozoans, of which many are parasitic, and possess complex lifecycles which alternate between mammalian and arthropod hosts. As is the case with most organisms, molecular chaperones and heat shock proteins are encoded within the genomes of these protozoans. These proteins are an integral part of maintaining the structural integrity of proteins during normal and stress conditions. Heat shock protein 40 (Hsp40) is a co-chaperone of heat shock protein 70 (Hsp70) and in some cases can act as a chaperone. These proteins work together to bind non-native polypeptide structures to prevent unfolded protein aggregrate formation in times of stress, translocate proteins across organelle membranes, and transport unsalvageable proteins to proteolytic degradation by the cellular proteasome. Hsp40s are divided into four types based on their domain structure. Analysis of the nuclear genomes of eight trypanosomatid species revealed that less than 10 of the approximate 70 Hsp40 sequences per genome were Type 1 Hsp40s, many of which contained putative orthologues in the other seven trypanosomatid genomes. One of these Type 1 Hsp40s from T b. brucei, Trypanosoma brucei DnaJ 2 (Tbj2), was functionally characterised in T brucei brucei. RNA interference knockdown of expression in T brucei brucei showed that cells deficient in Tbj2 displayed a severe inhibition of the growth of the cell population. The levels of the Tbj2 protein population in T brucei brucei cells increases after exposure to 42°c and the protein was found to have a generalized cytoplasmic subcellular localization at 37°c. These findings provide evidence that Tbj2 is an orthologue of Yeast DnaJ 1 (Y dj l), an essential S. cerevisiae protein. Hsp40s interact with their partner Hsp70s through their J-domain. The amino acids of the J-domain important for a functional interaction with Hsp70 were examined in Trypanosoma cruzi DnaJ 2 (Tcj2) (the orthologue of Tbj2) and T cruzi DnaJ protein 3 (Tcj3) by testing their ability to substitute for Y dj l in Saccharomyces cerevisae and for DnaJ in Escherichia coli. In both systems, the positively charged amino acids of Helix II and III of the J-domain disrupted the functional interaction of these Hsp40s with their partner Hsp70s. Substitutions in Helix I and IV of the J-domains of Tcj2 and Tcj3 produced varied results in the two different systems, possibly suggesting that these helices serve to define with which Hsp70s a given Hsp40 can interact. The inability of an Hsp40 and an Hsp70 to interact functionally does not necessarily mean a total absence of physical interaction between these proteins. The amino acid substitution of the histidine in the HPD motif (H34Q) of the J-domain of Tcj2 and Tcj3 removed the ability of these proteins to interact functionally with S. cerevisiae Hsp70 (Ssal) in vivo. However, preliminary binding studies using the quartz crystal microbalance with dissipation monitoring (QCM-D) show that Tcj2 and Tcj2(H34Q) both physically interact with M sativa Hsp70 in vitro. This study is the first report to provide evidence that certain trypanosoma! Type 1 Hsp40s are essential proteins. Futhermore, the interaction of these Hsp40s with Hsp70 identified important features of the functional interface of this chaperone machinery.
- Full Text:
- Date Issued: 2010
The characteristics and role of informal leaders in work groups : a South African perspective
- Authors: Wienekus, Barend Willem
- Date: 2010
- Subjects: Supervisors, industrial -- South Africa Leadership -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:1166 , http://hdl.handle.net/10962/d1002782
- Description: It has been twenty years since F W De Klerk unbanned the African National Congress. This momentous occasion changed overnight the business landscape in South Africa and the way business were done for many decades. Before and after this crucial moment in South African history, leaders played a significant role in bringing change about as well as managing it. Whether hierarchical or non-hierarchical, leadership manifests itself through all spheres of civilisation. Within any collective, formal as well as informal leadership are always at work and within the environment there always seems to be an individual that appears to hold equal or more influence and sway over the collective. This research investigates the characteristics and role of this individual, the informal leader. In addition, against the melting pot of the diversity of culture, social structures, economics, and demographics in South Africa, the influence of culture on how leadership is being perceived and experienced is also researched. The research is grounded in a post-positivists approach and conducted within a constructivist-interpretative paradigm. A qualitative approach is followed with personal interviews as the method to collect the data from respondents. The interview protocol consists of a combination of questions containing questions of both a quantitative and qualitative nature. Questions of a qualitative nature were open-ended and of an in-depth nature. The research is two pronged. The focus of the research is an Original Equipment Manufacturer (OEM) in the South African Motor Industry and for the primary goal of the research data was collected from employees within work groups of the OEM. The primary research goal investigates the role and characteristics of informal leaders in work groups as seen and experienced by their fellow employees and if there is any congruence with that of the role and characteristics of formal leaders. The study found no fundamental differences between the characteristics and role of formal and informal leaders. The characteristics and role of leaders between different cultures also appear to be the same. For the secondary research goal – determining whether the role and characteristics of informal leaders in work groups could be underpinned in the principles of Ubuntu and if consideration should be given to any cultural differences between leaders and followers by organisational hierarchies – the literature was reviewed in order to reach a conclusion with regards this goal. The literature indicates that culture does affect leadership, especially on how the leadership is executed and experienced in a multicultural society and if ignored, will have a detrimental effect on effective leadership. In order to strive towards achieving maximum productivity, it is imperative that management in South African organisations be aware of the changed dynamic within their organisations as well as on the global stage. The research therefore ends with the practical implications of informal leaders for organisations in South Africa. It is recommended that the importance and contribution of informal leaders within work groups in a multi-culture organisation needs not only to be considered as an element of group leadership, but should be accommodated by the organisation. It is also recommended that organisations recognise the cultural differences between leaders and followers in organisations and the possible consequences if ignored. If the competitive pressures and requirements of globalisation are ignored against the background of Afrocentric expectations and motivational imperatives of the South African workforce, it will result in an ineffective workforce, which will in due course render these organisations uncompetitive and non-sustainable locally and globally.
- Full Text:
- Date Issued: 2010
- Authors: Wienekus, Barend Willem
- Date: 2010
- Subjects: Supervisors, industrial -- South Africa Leadership -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:1166 , http://hdl.handle.net/10962/d1002782
- Description: It has been twenty years since F W De Klerk unbanned the African National Congress. This momentous occasion changed overnight the business landscape in South Africa and the way business were done for many decades. Before and after this crucial moment in South African history, leaders played a significant role in bringing change about as well as managing it. Whether hierarchical or non-hierarchical, leadership manifests itself through all spheres of civilisation. Within any collective, formal as well as informal leadership are always at work and within the environment there always seems to be an individual that appears to hold equal or more influence and sway over the collective. This research investigates the characteristics and role of this individual, the informal leader. In addition, against the melting pot of the diversity of culture, social structures, economics, and demographics in South Africa, the influence of culture on how leadership is being perceived and experienced is also researched. The research is grounded in a post-positivists approach and conducted within a constructivist-interpretative paradigm. A qualitative approach is followed with personal interviews as the method to collect the data from respondents. The interview protocol consists of a combination of questions containing questions of both a quantitative and qualitative nature. Questions of a qualitative nature were open-ended and of an in-depth nature. The research is two pronged. The focus of the research is an Original Equipment Manufacturer (OEM) in the South African Motor Industry and for the primary goal of the research data was collected from employees within work groups of the OEM. The primary research goal investigates the role and characteristics of informal leaders in work groups as seen and experienced by their fellow employees and if there is any congruence with that of the role and characteristics of formal leaders. The study found no fundamental differences between the characteristics and role of formal and informal leaders. The characteristics and role of leaders between different cultures also appear to be the same. For the secondary research goal – determining whether the role and characteristics of informal leaders in work groups could be underpinned in the principles of Ubuntu and if consideration should be given to any cultural differences between leaders and followers by organisational hierarchies – the literature was reviewed in order to reach a conclusion with regards this goal. The literature indicates that culture does affect leadership, especially on how the leadership is executed and experienced in a multicultural society and if ignored, will have a detrimental effect on effective leadership. In order to strive towards achieving maximum productivity, it is imperative that management in South African organisations be aware of the changed dynamic within their organisations as well as on the global stage. The research therefore ends with the practical implications of informal leaders for organisations in South Africa. It is recommended that the importance and contribution of informal leaders within work groups in a multi-culture organisation needs not only to be considered as an element of group leadership, but should be accommodated by the organisation. It is also recommended that organisations recognise the cultural differences between leaders and followers in organisations and the possible consequences if ignored. If the competitive pressures and requirements of globalisation are ignored against the background of Afrocentric expectations and motivational imperatives of the South African workforce, it will result in an ineffective workforce, which will in due course render these organisations uncompetitive and non-sustainable locally and globally.
- Full Text:
- Date Issued: 2010
The development and implementation of an evaluation for rural ICT projects in developing countries: an exploration of the Siyakhulu Living Lab, South Africa
- Authors: Pade Khene, Caroline Ileje
- Date: 2010
- Subjects: Siyakhula Living Lab Information technology -- South Africa -- Eastern Cape Rural development projects -- South Africa -- Eastern Cape Communication in economic development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1138 , http://hdl.handle.net/10962/d1002767
- Description: Rural development is a priority for poverty alleviation and development in developing countries, as the majority of the poor live in rural areas. Information and knowledge are key strategic resources for social and economic development as they empower rural communities with the ability to expand their choices through knowing what works best in their communities. Information and communication technologies (ICT) play a significant role in supporting rural development activities through providing supportive development information and creating essential interconnectivities between rural areas and more developed regions. However, rural ICT for development (ICT4D) is still at best a ‘working hypothesis’, faced with barriers and challenges associated with implementation and use in the rural environment; which threaten the success, sustainability or relevance of an ICT intervention. Many key questions remain largely unanswered, with no concrete or credible data to support a wide range of claims concerning the use of ICT for development. The evaluation of rural ICT projects is indispensable as it determines the need, effectiveness, impact, sustainability and extent of the awareness of the contribution such projects or programmes can make in poverty alleviation and development. Even so, existing ICT4D evaluations are confrontedwith shortcomings and challenges which influence the accuracy and reliability of evaluation conclusions. These shortcomings highlight the need to embark on a more comprehensive evaluation approach, sensitive to the rural environment. This research study was aimed at developing a comprehensive rural ICT evaluation framework to assess ICT projects and interventions that work toward supporting poverty eradication in rural communities. A multi-method approach was used to determine the multiple variables and components associated with rural ICT evaluation, and then to determine how these variables interrelate. The approach is founded on programme evaluation, ICT for development evaluation, and information systems evaluation. Firstly, key domains of programme evaluations combined with an exploration of the need and shortcomings of ICT4D evaluation, contributed to the development of a template to analyse existing ICT4D evaluation frameworks and information systems frameworks, based on a selection of criteria. The combined analysis of the two groups of frameworks compares and contrasts key characteristics that form the structure of a comprehensive evaluation. This analysis and a review of programme evaluation enabled the development of a Rural ICT Comprehensive Evaluation Framework (RICT-CEF) that encompasses the key components essential for a comprehensive evaluation of rural ICT projects. The theoretical framework aims to inform ICT intervention to improve and support rural development, through the application of fundamental and interconnected evaluation domains sensitive to the rural environment, throughout the project’s lifecycle. In order to obtain a better understanding and application of the RICT-CEF, a real-life case study investigation of the Siyakhula Living Lab reveals the lessons learned (shortcomings and suitability) from applying a prototype of the framework in a rural environment. The study is characteristically a rich case study, as the investigation occurs at two levels: 1) The actual evaluation of the project to obtain results to improve or guide the project, through applying domains of the RICT-CEF, and 2) Observing and investigating the application of the RICT-CEF framework to learn lessons from its evaluation process in a real-life context. The research study reveals the compatibility of the RICT-CEF framework in a real-life rural ICT intervention case, and builds lessons learned for enhancing the framework and guiding future evaluations in ICT4D. The RICT-CEF can possibly be viewed as a platform for the key domains and processes essential for the evaluation of ICT4D interventions; which can be customised for a variety of ICT projects, such that a comparative assessment of projects can provide measurement and further awareness of the impact of rural ICT in developing countries.
- Full Text:
- Date Issued: 2010
- Authors: Pade Khene, Caroline Ileje
- Date: 2010
- Subjects: Siyakhula Living Lab Information technology -- South Africa -- Eastern Cape Rural development projects -- South Africa -- Eastern Cape Communication in economic development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1138 , http://hdl.handle.net/10962/d1002767
- Description: Rural development is a priority for poverty alleviation and development in developing countries, as the majority of the poor live in rural areas. Information and knowledge are key strategic resources for social and economic development as they empower rural communities with the ability to expand their choices through knowing what works best in their communities. Information and communication technologies (ICT) play a significant role in supporting rural development activities through providing supportive development information and creating essential interconnectivities between rural areas and more developed regions. However, rural ICT for development (ICT4D) is still at best a ‘working hypothesis’, faced with barriers and challenges associated with implementation and use in the rural environment; which threaten the success, sustainability or relevance of an ICT intervention. Many key questions remain largely unanswered, with no concrete or credible data to support a wide range of claims concerning the use of ICT for development. The evaluation of rural ICT projects is indispensable as it determines the need, effectiveness, impact, sustainability and extent of the awareness of the contribution such projects or programmes can make in poverty alleviation and development. Even so, existing ICT4D evaluations are confrontedwith shortcomings and challenges which influence the accuracy and reliability of evaluation conclusions. These shortcomings highlight the need to embark on a more comprehensive evaluation approach, sensitive to the rural environment. This research study was aimed at developing a comprehensive rural ICT evaluation framework to assess ICT projects and interventions that work toward supporting poverty eradication in rural communities. A multi-method approach was used to determine the multiple variables and components associated with rural ICT evaluation, and then to determine how these variables interrelate. The approach is founded on programme evaluation, ICT for development evaluation, and information systems evaluation. Firstly, key domains of programme evaluations combined with an exploration of the need and shortcomings of ICT4D evaluation, contributed to the development of a template to analyse existing ICT4D evaluation frameworks and information systems frameworks, based on a selection of criteria. The combined analysis of the two groups of frameworks compares and contrasts key characteristics that form the structure of a comprehensive evaluation. This analysis and a review of programme evaluation enabled the development of a Rural ICT Comprehensive Evaluation Framework (RICT-CEF) that encompasses the key components essential for a comprehensive evaluation of rural ICT projects. The theoretical framework aims to inform ICT intervention to improve and support rural development, through the application of fundamental and interconnected evaluation domains sensitive to the rural environment, throughout the project’s lifecycle. In order to obtain a better understanding and application of the RICT-CEF, a real-life case study investigation of the Siyakhula Living Lab reveals the lessons learned (shortcomings and suitability) from applying a prototype of the framework in a rural environment. The study is characteristically a rich case study, as the investigation occurs at two levels: 1) The actual evaluation of the project to obtain results to improve or guide the project, through applying domains of the RICT-CEF, and 2) Observing and investigating the application of the RICT-CEF framework to learn lessons from its evaluation process in a real-life context. The research study reveals the compatibility of the RICT-CEF framework in a real-life rural ICT intervention case, and builds lessons learned for enhancing the framework and guiding future evaluations in ICT4D. The RICT-CEF can possibly be viewed as a platform for the key domains and processes essential for the evaluation of ICT4D interventions; which can be customised for a variety of ICT projects, such that a comparative assessment of projects can provide measurement and further awareness of the impact of rural ICT in developing countries.
- Full Text:
- Date Issued: 2010
The development and implementation of computer literacy terminology in isiXhosa
- Authors: Sam, Msindisi Scara
- Date: 2010
- Subjects: Xhosa language -- Data processing Computer literacy -- South Africa -- Dwesa-Cwebe Computer literacy -- South Africa -- Grahamstown Information technology -- South Africa -- Dwesa-Cwebe Information technology -- South Africa -- Grahamstown Computational linguistics -- South Africa -- Dwesa-Cwebe Computational linguistics -- South Africa -- Grahamstown Information technology -- South Africa -- Dwesa-Cwebe -- Social aspects Information technology -- South Africa -- Grahamstown -- Social aspects Digital divide -- South Africa -- Dwesa-Cwebe Communication in economic development -- South Africa -- Dwesa-Cwebe Communication in economic development -- South Africa -- Grahamstown South Africa-Norway Tertiary Education Development Programme Rhodes University. Dept. of African Languages
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3580 , http://hdl.handle.net/10962/d1002155
- Full Text:
- Date Issued: 2010
- Authors: Sam, Msindisi Scara
- Date: 2010
- Subjects: Xhosa language -- Data processing Computer literacy -- South Africa -- Dwesa-Cwebe Computer literacy -- South Africa -- Grahamstown Information technology -- South Africa -- Dwesa-Cwebe Information technology -- South Africa -- Grahamstown Computational linguistics -- South Africa -- Dwesa-Cwebe Computational linguistics -- South Africa -- Grahamstown Information technology -- South Africa -- Dwesa-Cwebe -- Social aspects Information technology -- South Africa -- Grahamstown -- Social aspects Digital divide -- South Africa -- Dwesa-Cwebe Communication in economic development -- South Africa -- Dwesa-Cwebe Communication in economic development -- South Africa -- Grahamstown South Africa-Norway Tertiary Education Development Programme Rhodes University. Dept. of African Languages
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3580 , http://hdl.handle.net/10962/d1002155
- Full Text:
- Date Issued: 2010
The E.coli RNA degradosome analysis of molecular chaperones and enolase
- Authors: Burger, Adélle
- Date: 2010
- Subjects: Molecular chaperones , Escherichia coli -- Biotechnology , Polyphosphates , Polyphosphates -- Biotechnology , RNA-protein interactions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3950 , http://hdl.handle.net/10962/d1004009 , Molecular chaperones , Escherichia coli -- Biotechnology , Polyphosphates , Polyphosphates -- Biotechnology , RNA-protein interactions
- Description: Normal mRNA turnover is essential for genetic regulation within cells. The E. coli RNA degradosome, a large multi-component protein complex which originates through specific protein interactions, has been referred to as the “RNA decay machine” and is responsible for mRNA turnover. The degradosome functions to process RNA and its key components have been identified. The scaffold protein is RNase E and it tethers the degradosome to the cytoplasmic membrane. Polynucleotide phosphorylase (PNPase), ATP-dependent RNA helicase (RhlB helicase) and the glycolytic enzyme enolase associate with RNase E to form the degradosome. Polyphosphate kinase associates with the degradosome in substoichiometric amounts, as do the molecular chaperones DnaK and GroEL. The role of DnaK as well as that of enolase in the RNA degradosome is unknown. Very limited research has been conducted on the components of the RNA degradosome under conditions of stress. The aim of this study was to understand the role played by enolase in the assembly of the degradosome under conditions of stress, as well as investigating the protein levels of molecular chaperones under these conditions. The RNA degradosome was successfully purified through its scaffold protein using nickel-affinity chromatography. In vivo studies were performed to investigate the protein levels of DnaK and GroEL present in the degradosome under conditions of heat stress, and whether GroEL could functionally replace DnaK in the degradosome. To investigate the recruitment of enolase to the degradosome under heat stress, a subcellular fractionation was performed to determine the localization of enolase upon heat shock in vivo. The elevated temperature resulted in an increased concentration of enolase in the membrane fraction. To determine whether there is an interaction between enolase and DnaK, enolase activity assays were conducted in vitro. The effect of DnaK on enolase activity was measured upon quantifying DnaK and adding it to the enolase assays. For the first time it was observed that the activity of enolase increased with the addition of substoichiometric amounts of DnaK. This indicates that DnaK may be interacting with the RNA degradosome via enolase.
- Full Text:
- Date Issued: 2010
- Authors: Burger, Adélle
- Date: 2010
- Subjects: Molecular chaperones , Escherichia coli -- Biotechnology , Polyphosphates , Polyphosphates -- Biotechnology , RNA-protein interactions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3950 , http://hdl.handle.net/10962/d1004009 , Molecular chaperones , Escherichia coli -- Biotechnology , Polyphosphates , Polyphosphates -- Biotechnology , RNA-protein interactions
- Description: Normal mRNA turnover is essential for genetic regulation within cells. The E. coli RNA degradosome, a large multi-component protein complex which originates through specific protein interactions, has been referred to as the “RNA decay machine” and is responsible for mRNA turnover. The degradosome functions to process RNA and its key components have been identified. The scaffold protein is RNase E and it tethers the degradosome to the cytoplasmic membrane. Polynucleotide phosphorylase (PNPase), ATP-dependent RNA helicase (RhlB helicase) and the glycolytic enzyme enolase associate with RNase E to form the degradosome. Polyphosphate kinase associates with the degradosome in substoichiometric amounts, as do the molecular chaperones DnaK and GroEL. The role of DnaK as well as that of enolase in the RNA degradosome is unknown. Very limited research has been conducted on the components of the RNA degradosome under conditions of stress. The aim of this study was to understand the role played by enolase in the assembly of the degradosome under conditions of stress, as well as investigating the protein levels of molecular chaperones under these conditions. The RNA degradosome was successfully purified through its scaffold protein using nickel-affinity chromatography. In vivo studies were performed to investigate the protein levels of DnaK and GroEL present in the degradosome under conditions of heat stress, and whether GroEL could functionally replace DnaK in the degradosome. To investigate the recruitment of enolase to the degradosome under heat stress, a subcellular fractionation was performed to determine the localization of enolase upon heat shock in vivo. The elevated temperature resulted in an increased concentration of enolase in the membrane fraction. To determine whether there is an interaction between enolase and DnaK, enolase activity assays were conducted in vitro. The effect of DnaK on enolase activity was measured upon quantifying DnaK and adding it to the enolase assays. For the first time it was observed that the activity of enolase increased with the addition of substoichiometric amounts of DnaK. This indicates that DnaK may be interacting with the RNA degradosome via enolase.
- Full Text:
- Date Issued: 2010
The effects of booster breaks during a sedentary night shift on physiological, psychomotor, psycho-physiological, and cognitive performance over a 3 night shift habituation phase
- Authors: Lombard, Wesley Ross
- Date: 2010
- Subjects: Night work , Shift systems , Performance , Exercise , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Cognition -- Effect of exercise on , Motor ability
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5116 , http://hdl.handle.net/10962/d1005194 , Night work , Shift systems , Performance , Exercise , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Cognition -- Effect of exercise on , Motor ability
- Description: Despite extensive research into shift work, workers working under rotating shift conditions are still plagued by the effects of the desynchronisation resulting from working against their natural circadian rhythms. Additionally, modern industries are shifting towards tasks requiring greater cognitive demand with less manual labour incorporated into the tasks. Research into operator based tasks, and hence those of a sedentary cognitive base both during day and night shifts, has been focusing on the effectiveness of the standard rest/break schedule. Research indicating that the standard rest break schedule is often ineffective in eliminating operator discomfort and performance deterioration, with these affects argued to be more pronounced during a night shift schedule. Therefore current research set out to investigate alternative rest break schedules, incorporating a short bout of physical activity and stretching exercises which are proposed to enhance performance and subjective mood, while eliminating operator discomfort for sedentary based cognitive tasks. Three conditions were tested during a three day habituation shift cycle within a laboratory, incorporating two night shift groups (control and experimental) and a control day shift group. Twelve subjects made up each group, with the two night shift groups completing the shift schedule together. The control groups followed a typical 8 hour shift schedule while the experimental group performed a booster break (exercise and stretches) activity for 7.5 minutes every hour during the night shift schedule. Over the course of the shift, subjects completed a battery of six tests providing data on physiological measurements (heart rate and temperature), performance criteria (reaction time responses, memory and neurobiological) and subjective measures. Responses obtained for all the different parameters measured indicated a strong circadian influence for the majority of the variables, indicating the course of natural down regulation within physiological and performance criteria over the night shift. The booster break significantly improved reaction time performance, subjective ratings and resulted in a high sustainable activity level. Day shift comparisons indicating that within subjective measures and reaction time performance, the booster break resulted in similar responses to those of the day shift workers, while the control night shift groups reported significantly lowers results. Additionally, the booster break had positive influences during the circadian nadir, significantly improving parameters of performance and subjective ratings of sleepiness. The results of this study indicating which variables are strong predictors and indicators of the oscillations in performance and subjective ratings due to the circadian changes. The booster break interventions had positive effects on subjective ratings and reaction time performance, while also being argued to decrease the burden placed on the cardiac system as a result of increased sympathetic tone during the night shift, while additionally resulting in similar responses to those of day shift workers. Further studies are required, however, to provide conclusive evidence particularly within a working situation over a longer shift schedule.
- Full Text:
- Date Issued: 2010
- Authors: Lombard, Wesley Ross
- Date: 2010
- Subjects: Night work , Shift systems , Performance , Exercise , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Cognition -- Effect of exercise on , Motor ability
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5116 , http://hdl.handle.net/10962/d1005194 , Night work , Shift systems , Performance , Exercise , Exercise -- Physiological aspects , Exercise -- Psychological aspects , Cognition -- Effect of exercise on , Motor ability
- Description: Despite extensive research into shift work, workers working under rotating shift conditions are still plagued by the effects of the desynchronisation resulting from working against their natural circadian rhythms. Additionally, modern industries are shifting towards tasks requiring greater cognitive demand with less manual labour incorporated into the tasks. Research into operator based tasks, and hence those of a sedentary cognitive base both during day and night shifts, has been focusing on the effectiveness of the standard rest/break schedule. Research indicating that the standard rest break schedule is often ineffective in eliminating operator discomfort and performance deterioration, with these affects argued to be more pronounced during a night shift schedule. Therefore current research set out to investigate alternative rest break schedules, incorporating a short bout of physical activity and stretching exercises which are proposed to enhance performance and subjective mood, while eliminating operator discomfort for sedentary based cognitive tasks. Three conditions were tested during a three day habituation shift cycle within a laboratory, incorporating two night shift groups (control and experimental) and a control day shift group. Twelve subjects made up each group, with the two night shift groups completing the shift schedule together. The control groups followed a typical 8 hour shift schedule while the experimental group performed a booster break (exercise and stretches) activity for 7.5 minutes every hour during the night shift schedule. Over the course of the shift, subjects completed a battery of six tests providing data on physiological measurements (heart rate and temperature), performance criteria (reaction time responses, memory and neurobiological) and subjective measures. Responses obtained for all the different parameters measured indicated a strong circadian influence for the majority of the variables, indicating the course of natural down regulation within physiological and performance criteria over the night shift. The booster break significantly improved reaction time performance, subjective ratings and resulted in a high sustainable activity level. Day shift comparisons indicating that within subjective measures and reaction time performance, the booster break resulted in similar responses to those of the day shift workers, while the control night shift groups reported significantly lowers results. Additionally, the booster break had positive influences during the circadian nadir, significantly improving parameters of performance and subjective ratings of sleepiness. The results of this study indicating which variables are strong predictors and indicators of the oscillations in performance and subjective ratings due to the circadian changes. The booster break interventions had positive effects on subjective ratings and reaction time performance, while also being argued to decrease the burden placed on the cardiac system as a result of increased sympathetic tone during the night shift, while additionally resulting in similar responses to those of day shift workers. Further studies are required, however, to provide conclusive evidence particularly within a working situation over a longer shift schedule.
- Full Text:
- Date Issued: 2010
The effects of glove fit on task performance and on the human operator
- Authors: Stack, Jessica Danielle
- Date: 2010
- Subjects: Hand -- Anatomy , Hand -- Wounds and injuries , Hand -- Care and hygiene , Gloves , Safety education, Industrial , Human-machine systems , Industrial safety , Industrial accidents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5119 , http://hdl.handle.net/10962/d1005197 , Hand -- Anatomy , Hand -- Wounds and injuries , Hand -- Care and hygiene , Gloves , Safety education, Industrial , Human-machine systems , Industrial safety , Industrial accidents
- Description: The hand is one of the most complex of all of the anatomical structures in the human body. It has been found that hand injuries are among the most frequent injuries that occur to the body, predominantly during industrial activities. It has therefore been concluded that more research is needed into protective factors, such as glove use. The design features of a glove emphasise either protection or performance. There is often a trade-off between increased safety and performance capability when donning gloves. It has been determined that gloves which are fitted and comfortable for the worker may provide the best compromise between protective functions and decreased performance. This investigation aimed to assess the influence of glove fit on the performance attributes of industrial tasks, as well as on the responses of the human operator. Glove fit was analysed as 35 male participants donned three different glove sizes during each test, including a best-fitting glove, a glove one size smaller than best-fitting, and a glove one size larger than best-fitting. For each glove size, gloves of two differing materials were tested, namely nitrile and neoprene. A barehanded condition was also tested, totalling seven gloved/barehanded conditions for each test. The seven conditions were assessed in a laboratory setting in a battery of tests. This consisted of components of task performance, including maximum pulling and pushing force, maximum torque, precision of force, tactility, speed and accuracy and dexterity. The performance responses were recorded, as well as participants’ perceptual responses using the Rating of Perceived Exertion scale, and muscle activity. Six muscles were selected: Flexor Digitorum Superficialis, Flexor Pollicus Longus, Extensor Carpi Ulnaris, Extensor Carpi Radialis, Flexor Carpi Ulnaris and Flexor Carpi Radialis. The results revealed that glove fit does affect certain spects of performance, and influences human operator responses for selected task components. Furthermore, discrepancies were distinguished between orking barehanded and working with an optimally fitted glove. There was also a glove material effect established. Overall, it was found that muscle activity when exerting maximum force in a pushing and pulling direction was optimal with the nitrile glove material. Maximum torque performance was enhanced with the use of a best-fitting glove, as compared with an ill-fitting glove or barehanded work. Force precision was preferable when barehanded, as opposed to the tactility task which rendered optimal results with a best-fitting glove. The same was found for speed and accuracy results, as glove fit appeared to have no effect on performance, but performance was improved when participants were barehanded. Dexterity performance was the most conclusively influenced by the conditions, resulting in barehanded performance being optimal. However, should a glove be necessary for a given task, an optimally-fitted glove which is of a thinner material would be recommended. It is necessary to distinguish the performance components of a task within industry and select the most appropriate glove for optimal performance and the least risk of overexertion.
- Full Text:
- Date Issued: 2010
- Authors: Stack, Jessica Danielle
- Date: 2010
- Subjects: Hand -- Anatomy , Hand -- Wounds and injuries , Hand -- Care and hygiene , Gloves , Safety education, Industrial , Human-machine systems , Industrial safety , Industrial accidents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5119 , http://hdl.handle.net/10962/d1005197 , Hand -- Anatomy , Hand -- Wounds and injuries , Hand -- Care and hygiene , Gloves , Safety education, Industrial , Human-machine systems , Industrial safety , Industrial accidents
- Description: The hand is one of the most complex of all of the anatomical structures in the human body. It has been found that hand injuries are among the most frequent injuries that occur to the body, predominantly during industrial activities. It has therefore been concluded that more research is needed into protective factors, such as glove use. The design features of a glove emphasise either protection or performance. There is often a trade-off between increased safety and performance capability when donning gloves. It has been determined that gloves which are fitted and comfortable for the worker may provide the best compromise between protective functions and decreased performance. This investigation aimed to assess the influence of glove fit on the performance attributes of industrial tasks, as well as on the responses of the human operator. Glove fit was analysed as 35 male participants donned three different glove sizes during each test, including a best-fitting glove, a glove one size smaller than best-fitting, and a glove one size larger than best-fitting. For each glove size, gloves of two differing materials were tested, namely nitrile and neoprene. A barehanded condition was also tested, totalling seven gloved/barehanded conditions for each test. The seven conditions were assessed in a laboratory setting in a battery of tests. This consisted of components of task performance, including maximum pulling and pushing force, maximum torque, precision of force, tactility, speed and accuracy and dexterity. The performance responses were recorded, as well as participants’ perceptual responses using the Rating of Perceived Exertion scale, and muscle activity. Six muscles were selected: Flexor Digitorum Superficialis, Flexor Pollicus Longus, Extensor Carpi Ulnaris, Extensor Carpi Radialis, Flexor Carpi Ulnaris and Flexor Carpi Radialis. The results revealed that glove fit does affect certain spects of performance, and influences human operator responses for selected task components. Furthermore, discrepancies were distinguished between orking barehanded and working with an optimally fitted glove. There was also a glove material effect established. Overall, it was found that muscle activity when exerting maximum force in a pushing and pulling direction was optimal with the nitrile glove material. Maximum torque performance was enhanced with the use of a best-fitting glove, as compared with an ill-fitting glove or barehanded work. Force precision was preferable when barehanded, as opposed to the tactility task which rendered optimal results with a best-fitting glove. The same was found for speed and accuracy results, as glove fit appeared to have no effect on performance, but performance was improved when participants were barehanded. Dexterity performance was the most conclusively influenced by the conditions, resulting in barehanded performance being optimal. However, should a glove be necessary for a given task, an optimally-fitted glove which is of a thinner material would be recommended. It is necessary to distinguish the performance components of a task within industry and select the most appropriate glove for optimal performance and the least risk of overexertion.
- Full Text:
- Date Issued: 2010
The evaluation of environmental reporting by publicly listed South African banks
- Authors: Oduro-Kwateng, George
- Date: 2010
- Subjects: Environmental reporting -- South Africa Banks and banking -- South Africa Social responsibility in banking -- South Africa Social responsibility of business -- South Africa Environmental protection -- South Africa Environmental economics -- South Africa Economic development -- South Africa -- Environmental aspects Environmental management -- South Africa Climatic changes -- South Africa Coalition for Environmentally Responsible Economies Global Reporting Initiative Standard Bank Limited Nedbank ABSA Bank
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:740 , http://hdl.handle.net/10962/d1003860
- Description: Recently, bankers have come to realise that banking operations, especially corporate lending, affect and are affected by the natural environment and that consequently, the banks might have an important role to play in helping to raise environmental standards. Although the environment presents significant risks to banks, in particular environmental credit risk, it also perhaps presents profitable opportunities. Stricter environmental regulations have forced companies to invest in environmentally friendly technologies and pollution control measures and in tum generated lending opportunities for bankers. This research examines the corporate practices of three of the four dominant banks in South Africa with respect to the environment, focusing on issues of climate change and environmental risk management by way of reporting and disclosure to all stakeholders. The emphasis on environmental reporting by South African banks has been reinforced by the latest release of the King III Report on Corporate Governance in South Africa. Global governance requires that the triple-bottom line should be applied in all corporate undertakings due to globalisation and trade liberalisation; however, the banking sector has responded poorly to the clarion call. The false view that the banks have no significant relationship with environmental degradation is being disproved. Environmental management is a huge and massive reconstruction of what has gone wrong with nature by human influence. The South African banks have had to face with the challenging tasks of reporting on the direct and mostly the indirect impacts of their environmental activities. Based on the three sampled banks which incidentally had greater percentages of the market capitalizations, the banks have fairly performed in environmental reporting. For example, Standard Bank (SA) Ltd has just signed the Equator Principles in 2007 implying corporate lending was done in 2007 without any respect to environmental impact assessments by corporate borrowers. Consequently, environmental reporting was not done to facilitate informed decision-making by stakeholders mostly shareholders and the communities where borrowers tun businesses. The objective of this research study is to investigate the extent and quantity of/voluntary environmental disclosures in the annual and sustainability reports of the banks listed on Johannesburg Stock Exchange. The periods examined were those subsequent to the release of the Exposure Draft Coalition for Environmentally Responsible Economies (CERES) Global Reporting Initiatives (GRI) issued in 1999. Using content analysis to focus on the environmental aspects, the research study compared three annual reports and three sustainability reports of 2007 year for the three sampled banks in order to evaluate reporting practices in the period surrounding this intervention. The results suggest a trend to triple bottom-line reporting and the extent and quantity of environmental information, albeit in specific categories.
- Full Text:
- Date Issued: 2010
- Authors: Oduro-Kwateng, George
- Date: 2010
- Subjects: Environmental reporting -- South Africa Banks and banking -- South Africa Social responsibility in banking -- South Africa Social responsibility of business -- South Africa Environmental protection -- South Africa Environmental economics -- South Africa Economic development -- South Africa -- Environmental aspects Environmental management -- South Africa Climatic changes -- South Africa Coalition for Environmentally Responsible Economies Global Reporting Initiative Standard Bank Limited Nedbank ABSA Bank
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:740 , http://hdl.handle.net/10962/d1003860
- Description: Recently, bankers have come to realise that banking operations, especially corporate lending, affect and are affected by the natural environment and that consequently, the banks might have an important role to play in helping to raise environmental standards. Although the environment presents significant risks to banks, in particular environmental credit risk, it also perhaps presents profitable opportunities. Stricter environmental regulations have forced companies to invest in environmentally friendly technologies and pollution control measures and in tum generated lending opportunities for bankers. This research examines the corporate practices of three of the four dominant banks in South Africa with respect to the environment, focusing on issues of climate change and environmental risk management by way of reporting and disclosure to all stakeholders. The emphasis on environmental reporting by South African banks has been reinforced by the latest release of the King III Report on Corporate Governance in South Africa. Global governance requires that the triple-bottom line should be applied in all corporate undertakings due to globalisation and trade liberalisation; however, the banking sector has responded poorly to the clarion call. The false view that the banks have no significant relationship with environmental degradation is being disproved. Environmental management is a huge and massive reconstruction of what has gone wrong with nature by human influence. The South African banks have had to face with the challenging tasks of reporting on the direct and mostly the indirect impacts of their environmental activities. Based on the three sampled banks which incidentally had greater percentages of the market capitalizations, the banks have fairly performed in environmental reporting. For example, Standard Bank (SA) Ltd has just signed the Equator Principles in 2007 implying corporate lending was done in 2007 without any respect to environmental impact assessments by corporate borrowers. Consequently, environmental reporting was not done to facilitate informed decision-making by stakeholders mostly shareholders and the communities where borrowers tun businesses. The objective of this research study is to investigate the extent and quantity of/voluntary environmental disclosures in the annual and sustainability reports of the banks listed on Johannesburg Stock Exchange. The periods examined were those subsequent to the release of the Exposure Draft Coalition for Environmentally Responsible Economies (CERES) Global Reporting Initiatives (GRI) issued in 1999. Using content analysis to focus on the environmental aspects, the research study compared three annual reports and three sustainability reports of 2007 year for the three sampled banks in order to evaluate reporting practices in the period surrounding this intervention. The results suggest a trend to triple bottom-line reporting and the extent and quantity of environmental information, albeit in specific categories.
- Full Text:
- Date Issued: 2010
The ichthyofauna and piscivorous avifauna in a small temporarily open/closed Eastern Cape estuary, South Africa
- Authors: Blake, Justin David
- Date: 2010
- Subjects: Estuarine fishes -- South Africa -- Eastern Cape , Bird populations -- South Africa -- Riet River Estuary , Estuaries -- South Africa -- Eastern Cape , Fish populations -- South Africa -- Riet River Estuary , Estuarine animals -- South Africa -- Riet River Estuary , Birds -- South Africa -- Riet River Estuary , Riet River Estuary (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5709 , http://hdl.handle.net/10962/d1005395 , Estuarine fishes -- South Africa -- Eastern Cape , Bird populations -- South Africa -- Riet River Estuary , Estuaries -- South Africa -- Eastern Cape , Fish populations -- South Africa -- Riet River Estuary , Estuarine animals -- South Africa -- Riet River Estuary , Birds -- South Africa -- Riet River Estuary , Riet River Estuary (South Africa)
- Description: The spatial and temporal patterns in selected components of the ichthyofauna and piscivorous avifauna in the small temporarily open/closed Riet River Estuary located on the eastern seaboard of southern Africa was investigated monthly over the period August 2005 to July 2006. The ichthyofauna within the littoral zone of the estuary was sampled using a 5 m seine net (8 stations) while a 30 m seine net (4 stations) was employed to sample the fish in the channel. Bird counts were made along repeat transects along the length of the estuary. Total ichthyofaunal abundances and biomass ranged between 1.60 and 8.67 individuals m⁻² and 0.45 to 21.76 g wwt m⁻² within the littoral zone, and between 0.08 and 0.44 individuals m⁻² and 0.58 and 36.52 g wwt m⁻² in the channel of the estuary. The highest values were generally recorded during the summer months. Results of the numerical analysis indicated that the breaching events recorded over the study period did not lead to a common trend in the ichthyofaunal community. In the absence of a link to the marine environment, the ichthyofaunal community in the littoral zone was numerically dominated by the estuarine resident species, Gilchristella aestuaria and to a lesser extent by Glossogobius callidus, which collectively accounted for ca. 54% of the total ichthyofauna sampled. The establishment of a link to the marine environment coincided with increased numbers of marine breeding species including Atherina breviceps and Rhabdosargus holubi to total fish counts within the estuary. Hierarchical cluster analysis did not identify any spatial patterns in the community structure of the ichthyofauna in the littoral zone or channel zone of the estuary, which could likely be linked to the absence of any distinct horizontal patterns in salinity and temperature within the system. A total of thirteen piscivorous bird species was recorded over the study period. Of the recorded species, six species were wading piscivores, four species were aerial divers and the remaining three species were pursuit swimmers. There were no significant correlations between the estimates of the ichthyofaunal abundance and biomass and bird numbers evident during the study (P> 0.05 in both cases). The Reed Cormorant (Phalacrocorax africanus) was the dominant species throughout the study, with a mean of 8.25 (SD ± 7.90) individuals per count. Mean values of the Pied Kingfisher (Ceryle rudis) and Giant Kingfisher (Megaceryle maximus) were 3.42 (SD ± 1.20) and 1.17 (SD ± 0.60) individuals per count, respectively. The remaining species revealed mean values < 0.5 individuals per count. The highest bird numbers were recorded in winter reflecting the migration of large numbers of the Reed Cormorant into the system. Breaching events were associated with a decrease in total bird numbers, which was most likely due to loss of potential foraging habitat (littoral zone) for waders resulting from reduced water levels. Monthly food consumption by all piscivorous birds revealed large temporal variability, ranging from 26.35 to 140.58 kg per month. The observed variability could be linked to mouth phase and bird numbers.
- Full Text:
- Date Issued: 2010
- Authors: Blake, Justin David
- Date: 2010
- Subjects: Estuarine fishes -- South Africa -- Eastern Cape , Bird populations -- South Africa -- Riet River Estuary , Estuaries -- South Africa -- Eastern Cape , Fish populations -- South Africa -- Riet River Estuary , Estuarine animals -- South Africa -- Riet River Estuary , Birds -- South Africa -- Riet River Estuary , Riet River Estuary (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5709 , http://hdl.handle.net/10962/d1005395 , Estuarine fishes -- South Africa -- Eastern Cape , Bird populations -- South Africa -- Riet River Estuary , Estuaries -- South Africa -- Eastern Cape , Fish populations -- South Africa -- Riet River Estuary , Estuarine animals -- South Africa -- Riet River Estuary , Birds -- South Africa -- Riet River Estuary , Riet River Estuary (South Africa)
- Description: The spatial and temporal patterns in selected components of the ichthyofauna and piscivorous avifauna in the small temporarily open/closed Riet River Estuary located on the eastern seaboard of southern Africa was investigated monthly over the period August 2005 to July 2006. The ichthyofauna within the littoral zone of the estuary was sampled using a 5 m seine net (8 stations) while a 30 m seine net (4 stations) was employed to sample the fish in the channel. Bird counts were made along repeat transects along the length of the estuary. Total ichthyofaunal abundances and biomass ranged between 1.60 and 8.67 individuals m⁻² and 0.45 to 21.76 g wwt m⁻² within the littoral zone, and between 0.08 and 0.44 individuals m⁻² and 0.58 and 36.52 g wwt m⁻² in the channel of the estuary. The highest values were generally recorded during the summer months. Results of the numerical analysis indicated that the breaching events recorded over the study period did not lead to a common trend in the ichthyofaunal community. In the absence of a link to the marine environment, the ichthyofaunal community in the littoral zone was numerically dominated by the estuarine resident species, Gilchristella aestuaria and to a lesser extent by Glossogobius callidus, which collectively accounted for ca. 54% of the total ichthyofauna sampled. The establishment of a link to the marine environment coincided with increased numbers of marine breeding species including Atherina breviceps and Rhabdosargus holubi to total fish counts within the estuary. Hierarchical cluster analysis did not identify any spatial patterns in the community structure of the ichthyofauna in the littoral zone or channel zone of the estuary, which could likely be linked to the absence of any distinct horizontal patterns in salinity and temperature within the system. A total of thirteen piscivorous bird species was recorded over the study period. Of the recorded species, six species were wading piscivores, four species were aerial divers and the remaining three species were pursuit swimmers. There were no significant correlations between the estimates of the ichthyofaunal abundance and biomass and bird numbers evident during the study (P> 0.05 in both cases). The Reed Cormorant (Phalacrocorax africanus) was the dominant species throughout the study, with a mean of 8.25 (SD ± 7.90) individuals per count. Mean values of the Pied Kingfisher (Ceryle rudis) and Giant Kingfisher (Megaceryle maximus) were 3.42 (SD ± 1.20) and 1.17 (SD ± 0.60) individuals per count, respectively. The remaining species revealed mean values < 0.5 individuals per count. The highest bird numbers were recorded in winter reflecting the migration of large numbers of the Reed Cormorant into the system. Breaching events were associated with a decrease in total bird numbers, which was most likely due to loss of potential foraging habitat (littoral zone) for waders resulting from reduced water levels. Monthly food consumption by all piscivorous birds revealed large temporal variability, ranging from 26.35 to 140.58 kg per month. The observed variability could be linked to mouth phase and bird numbers.
- Full Text:
- Date Issued: 2010
The identification and evaluation of key sustainable development indicators and the development of a conceptual decision-making model for capital investment within Gold Fields Limited (GFL)
- Authors: Jacobs, Phillip A H
- Date: 2010
- Subjects: Industrial management -- Environmental aspects -- South Africa -- Case studies Social responsibility of business -- South Africa -- Case studies Environmental protection -- South Africa -- Case studies Sustainable development -- South Africa -- Case studies Business ethics -- South Africa -- Case studies Industries -- Social aspects -- South Africa -- Case studies Industries -- Moral and ethical aspects -- South Africa -- Case studies Gold Fields Ltd -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:820 , http://hdl.handle.net/10962/d1008304
- Description: The current trends in sustainable development (SO) were examined in this study, which brought about the realisation that SO has become a business imperative. Mining, which is a highly impacting industry, is faced with the dilemma of implementing the principles of SO despite the realisation that its activities are severely limited by· the finite nature of the resource it is capitalising on. This reality, however, does not detract from the non-negotiable requirement for the industry to meet the increasing pressures to act responsibly towards the environment and the community in which it operates. Gold Fields has stepped up to the plate and has already taken several steps to achieve this end. These include the adoption of SO in its Vision, Values and strategies and the development and implementation of a SO framework to ensure the integration of the principles of SO into the business. Furthermore, Gold Fields has also entered into voluntary activities that further cement the commitment the company has towards so. These other initiatives include, inter alia, its International Council on Mining and Metals membership, UN Global Compact participation, becoming a signatory to the cyanide code, IS014001, and so on. This study focussed on several indicator categories and the identification of a set of supporting sustainable development indicators (SOls) for each, which included environmental, social, economic, technological, and ethics, legal and corporate governance (not in order of priority). These indicators were assessed by a carefully selected group of respondents whose collective wisdom and expertise were used to identify and weight supporting SOls for each of the indicator categories. These supporting SOls were in turn used to develop a model that is able to assist in the business's decision making processes when capital investment is being considered . A water treatment project that is currently being considered by Gold Fields was utilised to demonstrate how the decision making model can be applied to two different scenarios. The result clearly and successfully demonstrated that by proactively taking environmental, economic, social, technological, and ethics, legal and corporate governance considerations into account, a gold mining company is able to increase the level of SO of a capital investment project.
- Full Text:
- Date Issued: 2010
- Authors: Jacobs, Phillip A H
- Date: 2010
- Subjects: Industrial management -- Environmental aspects -- South Africa -- Case studies Social responsibility of business -- South Africa -- Case studies Environmental protection -- South Africa -- Case studies Sustainable development -- South Africa -- Case studies Business ethics -- South Africa -- Case studies Industries -- Social aspects -- South Africa -- Case studies Industries -- Moral and ethical aspects -- South Africa -- Case studies Gold Fields Ltd -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:820 , http://hdl.handle.net/10962/d1008304
- Description: The current trends in sustainable development (SO) were examined in this study, which brought about the realisation that SO has become a business imperative. Mining, which is a highly impacting industry, is faced with the dilemma of implementing the principles of SO despite the realisation that its activities are severely limited by· the finite nature of the resource it is capitalising on. This reality, however, does not detract from the non-negotiable requirement for the industry to meet the increasing pressures to act responsibly towards the environment and the community in which it operates. Gold Fields has stepped up to the plate and has already taken several steps to achieve this end. These include the adoption of SO in its Vision, Values and strategies and the development and implementation of a SO framework to ensure the integration of the principles of SO into the business. Furthermore, Gold Fields has also entered into voluntary activities that further cement the commitment the company has towards so. These other initiatives include, inter alia, its International Council on Mining and Metals membership, UN Global Compact participation, becoming a signatory to the cyanide code, IS014001, and so on. This study focussed on several indicator categories and the identification of a set of supporting sustainable development indicators (SOls) for each, which included environmental, social, economic, technological, and ethics, legal and corporate governance (not in order of priority). These indicators were assessed by a carefully selected group of respondents whose collective wisdom and expertise were used to identify and weight supporting SOls for each of the indicator categories. These supporting SOls were in turn used to develop a model that is able to assist in the business's decision making processes when capital investment is being considered . A water treatment project that is currently being considered by Gold Fields was utilised to demonstrate how the decision making model can be applied to two different scenarios. The result clearly and successfully demonstrated that by proactively taking environmental, economic, social, technological, and ethics, legal and corporate governance considerations into account, a gold mining company is able to increase the level of SO of a capital investment project.
- Full Text:
- Date Issued: 2010
The impact of a one-hour self-selected nap opportunity on physiological and performance variables during a simulated night shift
- Authors: Davy, Jonathan Patrick
- Date: 2010
- Subjects: Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5123 , http://hdl.handle.net/10962/d1005201 , Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Description: Napping has been explored extensively as a means of counteracting the negative effects associated with shift work. A significant amount of this research has focused on the implementation of scheduled naps, with few studies considering flexible nap schemes. The current study therefore aimed to assess the effects of a flexible nap opportunity on the physiological, cognitive, performance, neurophysiological and subjective responses of a group of non shift workers over the course of a three-day simulated night shift regime. Additional foci were the effects of the nap condition on the extent of the circadian adaptation of the subjects to the irregular work schedule and the circadian-related influences associated with being awake during the night. 36 subjects – 18 males and 18 females – were recruited to participate in the current study. The data collection spanned twelve days, during which four, three-day long shift cycles were set up: three night shift cycles and one day shift cycle. During each night shift cycle, three separate experimental conditions were staggered, namely the nap condition, the no nap condition and a booster break condition (a collaborative study that completed the setup). The day shift served as a further comparison. Each cycle comprised of 12 subjects, which meant there were four subjects per condition during each cycle. The shifts were 8 hours in duration, with the no nap group following a standard break schedule evinced in industry. The three breaks taken during the shifts amounted to a total time of 1 hour. The nap group was afforded a 1 hour flexible nap opportunity between 00h00 and 03h00 with no other breaks. Therefore, both conditions had the same amount of work time. During the shifts, subjects performed two simple, low arousal tasks (beading and packing) and completed a test battery roughly every two hours which was comprised of physiological, performance, neurophysiological and subjective measures. It was found that the inclusion of the nap opportunity significantly improved output performance and response time during a low precision, modified Fitts tapping task over the course of three night shifts, relative to no napping. Physiologically, napping resulted in higher heart rate frequency measures by the end of the shifts, which were also accompanied by significant reductions in subjective sleepiness ratings during all iii the night shifts. The nap group’s responses in this case, did not differ significantly from those of the day shift. Both simple reaction time and memory performances improved as a result of the nap inclusion, but only during the third night shift. The majority of the measures included in the research also depicted the effects of the circadian rhythm, which was indicative of the pronounced effect that this natural biological down regulation has on performance during the night. Napping reduced the severity of these effects during beading performance and measures of subjective sleepiness. With regard to habituation, the nap opportunity also resulted in positive changes in the responses of beading performance, high precision response time, simple reaction time and both subjective sleepiness measures, relative to no napping. Sleep diary responses indicated that although sleep length and quality during the day were significantly reduced for both night-time conditions, recovery sleep (length and quality) for the nap group did not differ significantly from the no nap group. The findings of this research indicate that the inclusion of a flexible napping opportunity during the night shift had positive effects on some physiological, performance and subjective responses, and that this intervention is as beneficial as scheduled napping. Specifically, napping resulted in a significantly higher output during the beading task, relative to the no nap group despite the duration of work time being the same. As such the introduction of a flexible, self-selected nap opportunity is a practical, effective and individual-specific means of alleviating the negative effects of shift work, while improving certain performance parameters. Therefore, industries should consider its inclusion in their fatigue management programs. However, contextspecific considerations must be made, with regard work scheduling, individual differences and task demands when implementing such an intervention. This will ensure that its introduction will be well received and in time, lessen the health and work-related decrements associated with shift work.
- Full Text:
- Date Issued: 2010
- Authors: Davy, Jonathan Patrick
- Date: 2010
- Subjects: Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5123 , http://hdl.handle.net/10962/d1005201 , Night work , Naps (sleep) in the workplace , Naps (sleep) in the workplace -- Case studies , Shift systems
- Description: Napping has been explored extensively as a means of counteracting the negative effects associated with shift work. A significant amount of this research has focused on the implementation of scheduled naps, with few studies considering flexible nap schemes. The current study therefore aimed to assess the effects of a flexible nap opportunity on the physiological, cognitive, performance, neurophysiological and subjective responses of a group of non shift workers over the course of a three-day simulated night shift regime. Additional foci were the effects of the nap condition on the extent of the circadian adaptation of the subjects to the irregular work schedule and the circadian-related influences associated with being awake during the night. 36 subjects – 18 males and 18 females – were recruited to participate in the current study. The data collection spanned twelve days, during which four, three-day long shift cycles were set up: three night shift cycles and one day shift cycle. During each night shift cycle, three separate experimental conditions were staggered, namely the nap condition, the no nap condition and a booster break condition (a collaborative study that completed the setup). The day shift served as a further comparison. Each cycle comprised of 12 subjects, which meant there were four subjects per condition during each cycle. The shifts were 8 hours in duration, with the no nap group following a standard break schedule evinced in industry. The three breaks taken during the shifts amounted to a total time of 1 hour. The nap group was afforded a 1 hour flexible nap opportunity between 00h00 and 03h00 with no other breaks. Therefore, both conditions had the same amount of work time. During the shifts, subjects performed two simple, low arousal tasks (beading and packing) and completed a test battery roughly every two hours which was comprised of physiological, performance, neurophysiological and subjective measures. It was found that the inclusion of the nap opportunity significantly improved output performance and response time during a low precision, modified Fitts tapping task over the course of three night shifts, relative to no napping. Physiologically, napping resulted in higher heart rate frequency measures by the end of the shifts, which were also accompanied by significant reductions in subjective sleepiness ratings during all iii the night shifts. The nap group’s responses in this case, did not differ significantly from those of the day shift. Both simple reaction time and memory performances improved as a result of the nap inclusion, but only during the third night shift. The majority of the measures included in the research also depicted the effects of the circadian rhythm, which was indicative of the pronounced effect that this natural biological down regulation has on performance during the night. Napping reduced the severity of these effects during beading performance and measures of subjective sleepiness. With regard to habituation, the nap opportunity also resulted in positive changes in the responses of beading performance, high precision response time, simple reaction time and both subjective sleepiness measures, relative to no napping. Sleep diary responses indicated that although sleep length and quality during the day were significantly reduced for both night-time conditions, recovery sleep (length and quality) for the nap group did not differ significantly from the no nap group. The findings of this research indicate that the inclusion of a flexible napping opportunity during the night shift had positive effects on some physiological, performance and subjective responses, and that this intervention is as beneficial as scheduled napping. Specifically, napping resulted in a significantly higher output during the beading task, relative to the no nap group despite the duration of work time being the same. As such the introduction of a flexible, self-selected nap opportunity is a practical, effective and individual-specific means of alleviating the negative effects of shift work, while improving certain performance parameters. Therefore, industries should consider its inclusion in their fatigue management programs. However, contextspecific considerations must be made, with regard work scheduling, individual differences and task demands when implementing such an intervention. This will ensure that its introduction will be well received and in time, lessen the health and work-related decrements associated with shift work.
- Full Text:
- Date Issued: 2010