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 on the nutritional value of seven accessions of cocoyam growing in South Africa
- Authors: Lewu, Muinat Nike
- Date: 2010
- Subjects: Taro , Nutrition , Field crops -- Nutrition , Taro -- Nutritional aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11305 , http://hdl.handle.net/10353/d1001054 , Taro , Nutrition , Field crops -- Nutrition , Taro -- Nutritional aspects
- Description: Cocoyam [Colocasia esculenta (L.) Schott] is widely cultivated as a staple food in the tropical and subtropical regions of the world. The crop, however, remains unpopular and not well known outside KwaZulu-Natal Province of South Africa where it is cultivated mainly for subsistence. The aims of the study were to collect local landraces (accessions) of the crop from where it is found growing within the country for various studies and also to document its nutritional values as well as the safety/toxicity of the crop. The study was carried out using various methods. These included a comparative assessment of the proximate, mineral and antinutrient compositions of cooked and uncooked tubers of a typical commercially available cocoyam and potato found in South African markets. These investigations were repeated for the tubers and leaves of available landraces (seven accessions) of C. esculenta found growing in the farmers’ fields in KwaZulu-Natal Province. Also, an in vivo toxicological study on cooked accessions of the local landraces was conducted to determine possible toxicity effects after consumption using albino rats as a model. The results revealed that commercially available cocoyam and potato tubers have very close nutritional components. Analysis of the proximate composition of seven accessions (UFCe1- UFCe7) of cooked and uncooked tubers of cocoyam indicated that UFCe7 was better in ash, crude protein, crude fibre and crude lipid contents but with higher moisture which could make it more vulnerable to microbial attack. No tubers of the seven accessions appeared to be ii outstandingly better than the others based on their mineral compositions. However, in terms of antinutritional factors, UFCe1, UFCe3 and UFCe7 had the least amounts of oxalate, tannins and phytate in their cooked states. It was discovered however, that the leaves of the accessions of this vegetable contain substantial amount of minerals, and therefore, can contribute significantly to the nutrient requirements of humans and could be recommended as a cheap source of nutrients in South Africa. None of the accessions was outstandingly better than the others in terms of their mineral contents and anti-nutritional factors. Moreover, the current study has shown that boiling the leaves of cocoyam prior to consumption is an effective way of reducing the antinutrient contents of the leaves of the plant thereby making it safe for consumption. The findings also revealed that cooking C. esculenta leaves may increase the levels of protein, fibre and lipid contents while cooking may also decrease the mineral, carbohydrate and caloric contents of the leaves of the accessions. The leafy vegetable may, therefore, be recommended as a cheap source of plant protein. Cooking improved the nutritive value as a result of the reduction in antinutrient levels, thereby improving the food quality in all the tuber and leaf samples used for this study. At the same time, cooked samples also suffered loss of some nutrients with respect to the proximate and mineral compositions. However, supplementation from other food sources that are rich in these nutrients is necessary when these crops are cooked for consumption. Any of the cocoyam accessions may be recommended for consumption for improved protein and mineral nutrients while tubers of accession UFCe7 have also shown good promise in terms of protein and fibre content availability. The results of the in vivo study, using the liver and kidney functional endpoints of weanling albino rats (Rattus norvegicus) maintained on different accessions of cooked cocoyam-based iii diets (UFCe1-UFCe7) for 28 days, revealed that all the accessions produced selective alterations on the hepatorenal indices of weanling rats. The highest alterations were produced by UFCe4 while the least was from UFCe2. These alterations may have consequential effects on the normal functioning of the liver and kidney of the animals. The UFCe2 exhibited the least toxicity risk among the accessions of C. esculenta growing in KwaZulu-Natal Province of South Africa.
- Full Text:
- Date Issued: 2010
- Authors: Lewu, Muinat Nike
- Date: 2010
- Subjects: Taro , Nutrition , Field crops -- Nutrition , Taro -- Nutritional aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11305 , http://hdl.handle.net/10353/d1001054 , Taro , Nutrition , Field crops -- Nutrition , Taro -- Nutritional aspects
- Description: Cocoyam [Colocasia esculenta (L.) Schott] is widely cultivated as a staple food in the tropical and subtropical regions of the world. The crop, however, remains unpopular and not well known outside KwaZulu-Natal Province of South Africa where it is cultivated mainly for subsistence. The aims of the study were to collect local landraces (accessions) of the crop from where it is found growing within the country for various studies and also to document its nutritional values as well as the safety/toxicity of the crop. The study was carried out using various methods. These included a comparative assessment of the proximate, mineral and antinutrient compositions of cooked and uncooked tubers of a typical commercially available cocoyam and potato found in South African markets. These investigations were repeated for the tubers and leaves of available landraces (seven accessions) of C. esculenta found growing in the farmers’ fields in KwaZulu-Natal Province. Also, an in vivo toxicological study on cooked accessions of the local landraces was conducted to determine possible toxicity effects after consumption using albino rats as a model. The results revealed that commercially available cocoyam and potato tubers have very close nutritional components. Analysis of the proximate composition of seven accessions (UFCe1- UFCe7) of cooked and uncooked tubers of cocoyam indicated that UFCe7 was better in ash, crude protein, crude fibre and crude lipid contents but with higher moisture which could make it more vulnerable to microbial attack. No tubers of the seven accessions appeared to be ii outstandingly better than the others based on their mineral compositions. However, in terms of antinutritional factors, UFCe1, UFCe3 and UFCe7 had the least amounts of oxalate, tannins and phytate in their cooked states. It was discovered however, that the leaves of the accessions of this vegetable contain substantial amount of minerals, and therefore, can contribute significantly to the nutrient requirements of humans and could be recommended as a cheap source of nutrients in South Africa. None of the accessions was outstandingly better than the others in terms of their mineral contents and anti-nutritional factors. Moreover, the current study has shown that boiling the leaves of cocoyam prior to consumption is an effective way of reducing the antinutrient contents of the leaves of the plant thereby making it safe for consumption. The findings also revealed that cooking C. esculenta leaves may increase the levels of protein, fibre and lipid contents while cooking may also decrease the mineral, carbohydrate and caloric contents of the leaves of the accessions. The leafy vegetable may, therefore, be recommended as a cheap source of plant protein. Cooking improved the nutritive value as a result of the reduction in antinutrient levels, thereby improving the food quality in all the tuber and leaf samples used for this study. At the same time, cooked samples also suffered loss of some nutrients with respect to the proximate and mineral compositions. However, supplementation from other food sources that are rich in these nutrients is necessary when these crops are cooked for consumption. Any of the cocoyam accessions may be recommended for consumption for improved protein and mineral nutrients while tubers of accession UFCe7 have also shown good promise in terms of protein and fibre content availability. The results of the in vivo study, using the liver and kidney functional endpoints of weanling albino rats (Rattus norvegicus) maintained on different accessions of cooked cocoyam-based iii diets (UFCe1-UFCe7) for 28 days, revealed that all the accessions produced selective alterations on the hepatorenal indices of weanling rats. The highest alterations were produced by UFCe4 while the least was from UFCe2. These alterations may have consequential effects on the normal functioning of the liver and kidney of the animals. The UFCe2 exhibited the least toxicity risk among the accessions of C. esculenta growing in KwaZulu-Natal Province of South Africa.
- Full Text:
- Date Issued: 2010
Surveillance of invasive vibro species in discharged aqueous efflents of wastewater treatment plants in the Eastern Cape province of South Africa
- Authors: Igbinosa, Etinosa Ogbomoede
- Date: 2010
- Subjects: Vibrio -- South Africa -- Eastern Cape , Water -- Fluoridation -- South Africa -- Eastern Cape , Water -- Pollution -- South Africa -- Eastern Cape , Effluent quality -- South Africa -- Eastern Cape , Water -- Purification -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11267 , http://hdl.handle.net/10353/245 , Vibrio -- South Africa -- Eastern Cape , Water -- Fluoridation -- South Africa -- Eastern Cape , Water -- Pollution -- South Africa -- Eastern Cape , Effluent quality -- South Africa -- Eastern Cape , Water -- Purification -- South Africa -- Eastern Cape
- Description: Vibrio infections remain a serious threat to public health. In the last decade, Vibrio disease outbreaks have created a painful awareness of the personal, economic, societal, and public health costs associated with the impact of contaminated water in the aquatic milieu. This study was therefore designed to assess the prevalence of Vibrio pathogens in the final effluents of wastewater treatment plants (WWTPs) in the Eastern Cape Province, as well as their abilities to survive the treatment processes of the activated sludge system either as free cells or as plankton-associated entities in relation to the physicochemical qualities of the effluents. Three wastewater treatment facilities were selected to represent typical urban, sub-urban and rural communities, and samples were collected monthly from August 2007 to July 2008 from the final effluent, discharge point, 500 meter upstream and downstream of the discharge points and analysed for physicochemical parameters, Vibrio pathogens prevalence and their antibiogram characteristics using both culture based and molecular techniques. Physicochemical parameters measured include pH, temperature, electrical conductivity, salinity, turbidity, total dissolved solid (TDS), dissolved oxygen (DO), chemical oxygen demand (COD), nitrate, nitrite and orthophosphate levels. Unacceptably high levels of the assayed parameters were observed in many cases for COD (<10 - 1180 mg/l), nitrate (0.08 - 13.14 mg NO3- as N/l), nitrite (0.06 - 6.78 mg NO2- as N/l), orthophosphate (0.07-4.81 mg PO43- as P/l), DO (1.24 - 11.22 mg/l) and turbidity (2.04 -159.06 NTU). Temperature, COD and nitrite varied significantly with season (P < 0.05), while pH, EC, salinity, TDS, COD, and nitrate all varied significantly with sampling site (P < 0.01; P < 0.05). In the rural wastewater treatment facility, free-living Vibrio densities varied from 0 to 3.45 × 101 cfu ml-1, while the plankton-associated Vibrio densities vary with plankton sizes as follows: 180 μm (0 – 4.50 × 103 cfu ml-1); 60 μm (0 – 4.86 × 103 cfu ml-1); 20 μm (0 – 1.9 × 105 cfu ml-1). The seasonal variations in the Vibrio densities in the 180 and 60 μm plankton size samples were significant (P < 0.05), while the 20 μm plankton size and free-living vibrios densities were not. Molecular confirmation of the presumptive vibrios isolates revealed V. fluvialis (36.5 percent), as the predominant species, followed by V. vulnificus (34.6 percent), and V. parahaemolyticus (23.1 percent), and V. metschnikovii (5.8 percent) (detected using only API 20 NE), suggesting high incidence of pathogenic Vibrio species in the final effluent of the wastewater facility. Correlation analysis suggested that the concentration of Vibrio species correlated negatively with salinity and temperature (P < 0.001 and P < 0.002 respectively) as well as with pH and turbidity (P < 0.001), in the final effluent. Population density of total Vibrio ranged from 2.1 × 101 to 4.36 × 104 cfu ml-1 and from 2.80 ×101 to 1.80 × 105 cfu ml-1 for the sub-urban and urban communities treatment facilities respectively. Vibrio species associated with 180 μm, 60 μm, and 20 μm plankton sizes, were observed at densities of 0 - 1.36 × 103 cfu ml-1, 0 - 8.40 × 102 cfu ml-1 and 0 - 6.80 × 102 cfu ml-1 respectively at the sub-urban community‘s WWTP. In the urban community, counts of culturable vibrios ranged from 0 - 2.80 × 102 cfu ml-1 (180 μm); 0 - 6.60 × 102 cfu ml-1 (60 μm) and 0 -1.80 × 103 cfu ml-1 (20 μm). Abundance of free-living Vibrio species varied between 0 and the orders of 102 and 103 cfu ml-1 in the sub-urban and urban communities WWTPs respectively. Molecular confirmation of the presumptive vibrios isolates revealed the presence of V. fluvialis (41.38 percent), V. vulnificus (34.48 percent), and V. parahaemolyticus (24.14 percent) in the sub-urban community effluents. In the urban community V. fluvialis (40 percent), V. vulnificus (36 percent), and V. parahaemolyticus (24 percent) were detected. There was no significant correlation between Vibrio abundance and season, either as free-living or plankton-associated entities, while Vibrio species abundance correlated positively with temperature (r = 0.565; P < 0.01), salinity and dissolved oxygen (P < 0.05). Turbidity and pH showed significant seasonal variation (P < 0.05) in both locations. The Vibrio strains showed the typical multi-antibiotic-resistance of an SXT element. They were resistant to sulfamethoxazole (Sul), trimethoprim (Tmp), cotrimoxazole (Cot), chloramphenicol (Chl) and streptomycin (Str), as well as other antibiotics such as ampicillin (Amp), penicillin (Pen), erythromycin (Ery), tetracycline (Tet), nalidixic acid (Nal), and gentamicin (Gen). The antibiotic resistance genes detected includes dfr18 and dfrA1 for trimethoprim; tetA, strB, floR, sul2 blaP1, for tetracycline, streptomycin, chloramphenicol, sulfamethoxazole and β-lactams respectively. A number of these genes were only recently described from clinical isolates, demonstrating genetic exchange between clinical and environmental Vibrio species. This study revealed that there was an adverse impact on the physicochemical characteristics of the receiving watershed as a result of the discharge of inadequately treated effluents from the wastewater treatment facilities. The occurrence of Vibrio species as plankton-associated entities confirms the role of plankton as potential reservoir for this pathogen. Also the treated final effluents are reservoirs of various antibiotics resistance genes. This could pose significant health and environmental risk to the biotic component of the environment including communities that rely on the receiving water for domestic purposes and may also affect the health status of the aquatic milieu in the receiving water. There is need for consistent monitoring programme by appropriate regulatory agencies to ensure compliance of the wastewater treatment facilities to regulatory effluent quality standards.
- Full Text:
- Date Issued: 2010
- Authors: Igbinosa, Etinosa Ogbomoede
- Date: 2010
- Subjects: Vibrio -- South Africa -- Eastern Cape , Water -- Fluoridation -- South Africa -- Eastern Cape , Water -- Pollution -- South Africa -- Eastern Cape , Effluent quality -- South Africa -- Eastern Cape , Water -- Purification -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11267 , http://hdl.handle.net/10353/245 , Vibrio -- South Africa -- Eastern Cape , Water -- Fluoridation -- South Africa -- Eastern Cape , Water -- Pollution -- South Africa -- Eastern Cape , Effluent quality -- South Africa -- Eastern Cape , Water -- Purification -- South Africa -- Eastern Cape
- Description: Vibrio infections remain a serious threat to public health. In the last decade, Vibrio disease outbreaks have created a painful awareness of the personal, economic, societal, and public health costs associated with the impact of contaminated water in the aquatic milieu. This study was therefore designed to assess the prevalence of Vibrio pathogens in the final effluents of wastewater treatment plants (WWTPs) in the Eastern Cape Province, as well as their abilities to survive the treatment processes of the activated sludge system either as free cells or as plankton-associated entities in relation to the physicochemical qualities of the effluents. Three wastewater treatment facilities were selected to represent typical urban, sub-urban and rural communities, and samples were collected monthly from August 2007 to July 2008 from the final effluent, discharge point, 500 meter upstream and downstream of the discharge points and analysed for physicochemical parameters, Vibrio pathogens prevalence and their antibiogram characteristics using both culture based and molecular techniques. Physicochemical parameters measured include pH, temperature, electrical conductivity, salinity, turbidity, total dissolved solid (TDS), dissolved oxygen (DO), chemical oxygen demand (COD), nitrate, nitrite and orthophosphate levels. Unacceptably high levels of the assayed parameters were observed in many cases for COD (<10 - 1180 mg/l), nitrate (0.08 - 13.14 mg NO3- as N/l), nitrite (0.06 - 6.78 mg NO2- as N/l), orthophosphate (0.07-4.81 mg PO43- as P/l), DO (1.24 - 11.22 mg/l) and turbidity (2.04 -159.06 NTU). Temperature, COD and nitrite varied significantly with season (P < 0.05), while pH, EC, salinity, TDS, COD, and nitrate all varied significantly with sampling site (P < 0.01; P < 0.05). In the rural wastewater treatment facility, free-living Vibrio densities varied from 0 to 3.45 × 101 cfu ml-1, while the plankton-associated Vibrio densities vary with plankton sizes as follows: 180 μm (0 – 4.50 × 103 cfu ml-1); 60 μm (0 – 4.86 × 103 cfu ml-1); 20 μm (0 – 1.9 × 105 cfu ml-1). The seasonal variations in the Vibrio densities in the 180 and 60 μm plankton size samples were significant (P < 0.05), while the 20 μm plankton size and free-living vibrios densities were not. Molecular confirmation of the presumptive vibrios isolates revealed V. fluvialis (36.5 percent), as the predominant species, followed by V. vulnificus (34.6 percent), and V. parahaemolyticus (23.1 percent), and V. metschnikovii (5.8 percent) (detected using only API 20 NE), suggesting high incidence of pathogenic Vibrio species in the final effluent of the wastewater facility. Correlation analysis suggested that the concentration of Vibrio species correlated negatively with salinity and temperature (P < 0.001 and P < 0.002 respectively) as well as with pH and turbidity (P < 0.001), in the final effluent. Population density of total Vibrio ranged from 2.1 × 101 to 4.36 × 104 cfu ml-1 and from 2.80 ×101 to 1.80 × 105 cfu ml-1 for the sub-urban and urban communities treatment facilities respectively. Vibrio species associated with 180 μm, 60 μm, and 20 μm plankton sizes, were observed at densities of 0 - 1.36 × 103 cfu ml-1, 0 - 8.40 × 102 cfu ml-1 and 0 - 6.80 × 102 cfu ml-1 respectively at the sub-urban community‘s WWTP. In the urban community, counts of culturable vibrios ranged from 0 - 2.80 × 102 cfu ml-1 (180 μm); 0 - 6.60 × 102 cfu ml-1 (60 μm) and 0 -1.80 × 103 cfu ml-1 (20 μm). Abundance of free-living Vibrio species varied between 0 and the orders of 102 and 103 cfu ml-1 in the sub-urban and urban communities WWTPs respectively. Molecular confirmation of the presumptive vibrios isolates revealed the presence of V. fluvialis (41.38 percent), V. vulnificus (34.48 percent), and V. parahaemolyticus (24.14 percent) in the sub-urban community effluents. In the urban community V. fluvialis (40 percent), V. vulnificus (36 percent), and V. parahaemolyticus (24 percent) were detected. There was no significant correlation between Vibrio abundance and season, either as free-living or plankton-associated entities, while Vibrio species abundance correlated positively with temperature (r = 0.565; P < 0.01), salinity and dissolved oxygen (P < 0.05). Turbidity and pH showed significant seasonal variation (P < 0.05) in both locations. The Vibrio strains showed the typical multi-antibiotic-resistance of an SXT element. They were resistant to sulfamethoxazole (Sul), trimethoprim (Tmp), cotrimoxazole (Cot), chloramphenicol (Chl) and streptomycin (Str), as well as other antibiotics such as ampicillin (Amp), penicillin (Pen), erythromycin (Ery), tetracycline (Tet), nalidixic acid (Nal), and gentamicin (Gen). The antibiotic resistance genes detected includes dfr18 and dfrA1 for trimethoprim; tetA, strB, floR, sul2 blaP1, for tetracycline, streptomycin, chloramphenicol, sulfamethoxazole and β-lactams respectively. A number of these genes were only recently described from clinical isolates, demonstrating genetic exchange between clinical and environmental Vibrio species. This study revealed that there was an adverse impact on the physicochemical characteristics of the receiving watershed as a result of the discharge of inadequately treated effluents from the wastewater treatment facilities. The occurrence of Vibrio species as plankton-associated entities confirms the role of plankton as potential reservoir for this pathogen. Also the treated final effluents are reservoirs of various antibiotics resistance genes. This could pose significant health and environmental risk to the biotic component of the environment including communities that rely on the receiving water for domestic purposes and may also affect the health status of the aquatic milieu in the receiving water. There is need for consistent monitoring programme by appropriate regulatory agencies to ensure compliance of the wastewater treatment facilities to regulatory effluent quality standards.
- Full Text:
- Date Issued: 2010
Synergistic potententials and isolation of bioactive compounds from the extracts of two helichrysum species indigenous to the Eastern Cape province
- Authors: Aiyegoro, Olayinka Ayobami
- Date: 2010
- Subjects: Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11268 , http://hdl.handle.net/10353/250 , Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Description: Helichrysum longifolium and H. pedunculatum belong to the Astereceae family and are used extensively in folkloric medicine in South Africa to manage stress-related ailments and as dressings for wounds normally encountered in circumcision rites, bruises, cuts and sores. The in vitro antibacterial time-kill studies, the synergistic potentials, the phytochemical screenings and antioxidant potentials as well as the isolation of the bioactive compounds from the extracts of these two plants were carried out in this study. The in vitro antibacterial activities and time kill regimes of crude extracts of H. pedunculatum was assessed. The extracts was active against both Gram positive and Gram negative bacteria tested at a concentration of 10 mg/ml. Minimum Inhibitory Concentration (MIC) values for all the susceptible bacteria ranged between 0.1 – 35 mg/ml. The average log reduction in viable cell count in time kill assay ranged between 0.17 Log10 to 6.37 Log10 cfu/ml after 6 h of interaction, and between 0.14 Log10 and 6.99 Log10 cfu/ml after 12 h interaction in 1 × MIC and 2 × MIC of the extract. The effect of the aqueous extract was only bacteriostatic on both reference and environmental strains and the clinical isolates were outrightly resistant to aqueous extract. This is worrisome and this could be one reason why, there is an incidence of high death rate resulting from circumcision wounds infection even after treating such wounds with H. pedunculatum leaf. In vitro antibacterial time kill studies of extracts of H. longifolium was assessed. All test bacteria were susceptible to the methanol extract, while none was susceptible to the aqueous extract. Two of the test bacteria were susceptible to the ethyl acetate extract, while ten and seven were susceptible to the acetone and chloroform extracts respectively at the test concentration of 5 mg/ml. The minimum inhibitory concentrations (MICs) ranged between 0.1 and 5.0 mg/ml, while minimum bactericidal concentrations (MBCs) ranged between 1.0 and >5 mg/ml for all the extracts. Average log reductions in viable cell counts for all the extracts ranged between 0.1 Log10 and 7.5 Log10 cfu/ml after 12 h interaction at 1 × MIC and 2 × MIC. Most of the extracts were rapidly bactericidal at 2 × MIC achieving a complete elimination of most of the test organisms within 12 h exposure time. The effect of combinations of the crude extracts of H. pedunculatum leaves and eight antibiotics was investigated by means of checkerboard and time-kill methods. In the checkerboard method, synergies of between 45.83-56.81 percent were observed and this is independent of Gram reaction, with combinations in the aqueous extract yielding largely antagonistic interactions (18.75 percent). The time kill assay also detected synergy that is independent of Gram reaction with a ≥ 3Log10 potentiation of the bactericidal activity of the test antibiotics. We conclude that the crude leaf extracts of H. pedunculatum could be potential source of broad spectrum antibiotics resistance modulating compounds. The interactions between crude extracts of H. longifolium in combination with six first-line antibiotics using both the time-kill and the checkerboard methods were carried out. The time-kill method revealed the highest bactericidal activity exemplified by a 6.7 Log10 reduction in cell density against Salmonella sp. when the extract and Penicillin G are combined at ½ × MIC. Synergistic response constituted about 65 percent, while indifference and antagonism constituted about 28.33 percent and 6.67 percent in the time kill assay, respectively. The checkerboard method also revealed that the extracts improved bactericidal effects of the antibiotics. About 61.67 percent of all the interactions were synergistic, while indifference interactions constituted about 26.67 percent and antagonistic interactions was observed in approximately 11.66 percent. The in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extracts of H. longifolium and H. pedunculatum was investigated. The scavenging activity on superoxide anions, DPPH, H2O2, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extracts. The extracts exhibited scavenging activity in all radicals tested due to the presence of relatively high total phenol and flavonoids contents in the extracts. Our findings suggest that H. longifolium and H. pedunculatum are endowed with antioxidant phytochemicals and could serve as a base for future drugs. Bioactivity-guided fractionation of the leaves of H. longifolium and H. pedunculatum yielded two known compounds. From the n-hexane fraction of H. longifolium a compound was isolated (Stigmasterol) and from the ethyl acetate fraction of H. pedunculatum another compound (β-sitosterol) was isolated. The compounds were isolated and identified using various techniques. The antimicrobial, anti-inflammatory, antioxidant, analgesic and anti-pyretic activities of these compounds have been reported in literatures. In general, the experiments and tests conducted in this study appear to have justified the folkloric medicinal uses of H. longifolium and H. pedunculatum for the treatment of stress related ailments and wound infections and make a substantial contribution to the knowledge base of the use of herbal medicine for the treatment of the microbial infections.
- Full Text:
- Date Issued: 2010
- Authors: Aiyegoro, Olayinka Ayobami
- Date: 2010
- Subjects: Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11268 , http://hdl.handle.net/10353/250 , Helichrysum -- South Africa -- Eastern Cape , Antibiotics , Antioxidants , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape
- Description: Helichrysum longifolium and H. pedunculatum belong to the Astereceae family and are used extensively in folkloric medicine in South Africa to manage stress-related ailments and as dressings for wounds normally encountered in circumcision rites, bruises, cuts and sores. The in vitro antibacterial time-kill studies, the synergistic potentials, the phytochemical screenings and antioxidant potentials as well as the isolation of the bioactive compounds from the extracts of these two plants were carried out in this study. The in vitro antibacterial activities and time kill regimes of crude extracts of H. pedunculatum was assessed. The extracts was active against both Gram positive and Gram negative bacteria tested at a concentration of 10 mg/ml. Minimum Inhibitory Concentration (MIC) values for all the susceptible bacteria ranged between 0.1 – 35 mg/ml. The average log reduction in viable cell count in time kill assay ranged between 0.17 Log10 to 6.37 Log10 cfu/ml after 6 h of interaction, and between 0.14 Log10 and 6.99 Log10 cfu/ml after 12 h interaction in 1 × MIC and 2 × MIC of the extract. The effect of the aqueous extract was only bacteriostatic on both reference and environmental strains and the clinical isolates were outrightly resistant to aqueous extract. This is worrisome and this could be one reason why, there is an incidence of high death rate resulting from circumcision wounds infection even after treating such wounds with H. pedunculatum leaf. In vitro antibacterial time kill studies of extracts of H. longifolium was assessed. All test bacteria were susceptible to the methanol extract, while none was susceptible to the aqueous extract. Two of the test bacteria were susceptible to the ethyl acetate extract, while ten and seven were susceptible to the acetone and chloroform extracts respectively at the test concentration of 5 mg/ml. The minimum inhibitory concentrations (MICs) ranged between 0.1 and 5.0 mg/ml, while minimum bactericidal concentrations (MBCs) ranged between 1.0 and >5 mg/ml for all the extracts. Average log reductions in viable cell counts for all the extracts ranged between 0.1 Log10 and 7.5 Log10 cfu/ml after 12 h interaction at 1 × MIC and 2 × MIC. Most of the extracts were rapidly bactericidal at 2 × MIC achieving a complete elimination of most of the test organisms within 12 h exposure time. The effect of combinations of the crude extracts of H. pedunculatum leaves and eight antibiotics was investigated by means of checkerboard and time-kill methods. In the checkerboard method, synergies of between 45.83-56.81 percent were observed and this is independent of Gram reaction, with combinations in the aqueous extract yielding largely antagonistic interactions (18.75 percent). The time kill assay also detected synergy that is independent of Gram reaction with a ≥ 3Log10 potentiation of the bactericidal activity of the test antibiotics. We conclude that the crude leaf extracts of H. pedunculatum could be potential source of broad spectrum antibiotics resistance modulating compounds. The interactions between crude extracts of H. longifolium in combination with six first-line antibiotics using both the time-kill and the checkerboard methods were carried out. The time-kill method revealed the highest bactericidal activity exemplified by a 6.7 Log10 reduction in cell density against Salmonella sp. when the extract and Penicillin G are combined at ½ × MIC. Synergistic response constituted about 65 percent, while indifference and antagonism constituted about 28.33 percent and 6.67 percent in the time kill assay, respectively. The checkerboard method also revealed that the extracts improved bactericidal effects of the antibiotics. About 61.67 percent of all the interactions were synergistic, while indifference interactions constituted about 26.67 percent and antagonistic interactions was observed in approximately 11.66 percent. The in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extracts of H. longifolium and H. pedunculatum was investigated. The scavenging activity on superoxide anions, DPPH, H2O2, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extracts. The extracts exhibited scavenging activity in all radicals tested due to the presence of relatively high total phenol and flavonoids contents in the extracts. Our findings suggest that H. longifolium and H. pedunculatum are endowed with antioxidant phytochemicals and could serve as a base for future drugs. Bioactivity-guided fractionation of the leaves of H. longifolium and H. pedunculatum yielded two known compounds. From the n-hexane fraction of H. longifolium a compound was isolated (Stigmasterol) and from the ethyl acetate fraction of H. pedunculatum another compound (β-sitosterol) was isolated. The compounds were isolated and identified using various techniques. The antimicrobial, anti-inflammatory, antioxidant, analgesic and anti-pyretic activities of these compounds have been reported in literatures. In general, the experiments and tests conducted in this study appear to have justified the folkloric medicinal uses of H. longifolium and H. pedunculatum for the treatment of stress related ailments and wound infections and make a substantial contribution to the knowledge base of the use of herbal medicine for the treatment of the microbial infections.
- Full Text:
- Date Issued: 2010
Synthesis, characterization and reactions of novel ferrocenylimidazoles as donor ligands
- Authors: Onyancha, Douglas Okerio
- Date: 2010
- Subjects: Ferrocene
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10390 , http://hdl.handle.net/10948/1150 , Ferrocene
- Description: In this project a series of ferrocenylimidazole derivatives were successfully prepared and characterized using an array of analytical techniques. Reactions of ferrocenylcarbinols with N,N′-thiocarbonyldiimidazole under both solvent-free conditions and in dichloromethane are described. The reaction of ferrocenylmethanol afforded S,S-bis(ferrocenylmethyl)dithiocarbonate, the reaction of α-substituted ferrocenylcarbinols provided ferrocenylalkylimidazolides, while ω-ferrocenylcarbinols yielded ferrocenylimidazolecarbothioates. The reactions were carried out under solvent-free conditions, consistent with the principles of Green Chemistry. Ferrocenyl benzyl ethers were successfully prepared by reacting 4-ferrocenylbenzyl-1Hcarboxylate with a series of primary alcohols under catalytic condition and under a catalyst– free environment. Refluxing a mixture of alcohol-water and 4-ferrocenylbenzyl-1Hcarboxylate provided the corresponding ethers in modest yields. The same ethers were obtained at room temperature by employing potassium tetrachloroplatinate or hydrochloric acid as catalyst. Ferrocenyl-1H-imidazole, 4-ferrocenylphenyl-1H-imidazole and their corresponding ferrocenyl-3-subsitituted imidazolium salts have been successfully synthesized. The compounds were characterized and the electrochemical properties of selected imidazolium salts were examined by cyclic voltammetry. Additionally, X-ray structures of two of the imidazolium salts were determined. The imidazolium salts were found to be good catalysts for the Heck and Suzuki cross-coupling reactions.
- Full Text:
- Date Issued: 2010
- Authors: Onyancha, Douglas Okerio
- Date: 2010
- Subjects: Ferrocene
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10390 , http://hdl.handle.net/10948/1150 , Ferrocene
- Description: In this project a series of ferrocenylimidazole derivatives were successfully prepared and characterized using an array of analytical techniques. Reactions of ferrocenylcarbinols with N,N′-thiocarbonyldiimidazole under both solvent-free conditions and in dichloromethane are described. The reaction of ferrocenylmethanol afforded S,S-bis(ferrocenylmethyl)dithiocarbonate, the reaction of α-substituted ferrocenylcarbinols provided ferrocenylalkylimidazolides, while ω-ferrocenylcarbinols yielded ferrocenylimidazolecarbothioates. The reactions were carried out under solvent-free conditions, consistent with the principles of Green Chemistry. Ferrocenyl benzyl ethers were successfully prepared by reacting 4-ferrocenylbenzyl-1Hcarboxylate with a series of primary alcohols under catalytic condition and under a catalyst– free environment. Refluxing a mixture of alcohol-water and 4-ferrocenylbenzyl-1Hcarboxylate provided the corresponding ethers in modest yields. The same ethers were obtained at room temperature by employing potassium tetrachloroplatinate or hydrochloric acid as catalyst. Ferrocenyl-1H-imidazole, 4-ferrocenylphenyl-1H-imidazole and their corresponding ferrocenyl-3-subsitituted imidazolium salts have been successfully synthesized. The compounds were characterized and the electrochemical properties of selected imidazolium salts were examined by cyclic voltammetry. Additionally, X-ray structures of two of the imidazolium salts were determined. The imidazolium salts were found to be good catalysts for the Heck and Suzuki cross-coupling reactions.
- Full Text:
- Date Issued: 2010
The adoption of quality assurance in e-Health acquisition for rural hospitals in the Eastern Cape Province
- Authors: Ruxwana, Nkqubela
- Date: 2010
- Subjects: Quality assurance -- Management , Hospital care -- Quality control , Health facilities -- Quality control , Health -- Computer network resources , Public health -- Information services
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9731 , http://hdl.handle.net/10948/1514 , Quality assurance -- Management , Hospital care -- Quality control , Health facilities -- Quality control , Health -- Computer network resources , Public health -- Information services
- Description: The evolution of e-health has the potential to assist in the management of scarce resources and the shortage of skills, enhance efficiencies, improve quality and increase work productivity within the healthcare sector. As a result, an increase is seen in e-health solutions developments with the aim to improve healthcare services, hospital information systems, health decision support, telemedicine and other technical systems that have the potential to reduce cost, improve quality, and enhance the accessibility and delivery of healthcare. However, unfortunately their implementation contiues to fail. Although there are several reasons for this, in this study a lack of project quality management is viewed as a key contributor to the failure of e-health solutions implementation projects in rural hospitals. This results in neglected aspects of quality assurance (QA), which forms an integral part of project quality management. The purpose of this study is to develop a Genertic Quality Assurance Model (GQAM) for the successful acquisition (i.e. development and implementation) of e-health solutions in rural hospitals in the Eastern Cape Province to enable improved quality of care and service delivery. In order to develop and test this model it was necessary to identify the QA methodologies that are currently used in rural hospitals and to evaluate their strengths and weaknesses, as well as their impact on project success. The study is divided into four phases; in each phase different study designs were followed. The study used triangulation of qualitative and some elements of quantitative research approaches, in terms of which a case study approach was adpoted to answer the research questions. This study did indeed develop a GQAM that can be used to ensure e-health solution success in rural hospitals. Furthermore, to aid in the implementation of this model, a set of QA value chain implementation guidelines were developed, as a framework, to inject the nodel into typical (SDLC) phases.
- Full Text:
- Date Issued: 2010
- Authors: Ruxwana, Nkqubela
- Date: 2010
- Subjects: Quality assurance -- Management , Hospital care -- Quality control , Health facilities -- Quality control , Health -- Computer network resources , Public health -- Information services
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9731 , http://hdl.handle.net/10948/1514 , Quality assurance -- Management , Hospital care -- Quality control , Health facilities -- Quality control , Health -- Computer network resources , Public health -- Information services
- Description: The evolution of e-health has the potential to assist in the management of scarce resources and the shortage of skills, enhance efficiencies, improve quality and increase work productivity within the healthcare sector. As a result, an increase is seen in e-health solutions developments with the aim to improve healthcare services, hospital information systems, health decision support, telemedicine and other technical systems that have the potential to reduce cost, improve quality, and enhance the accessibility and delivery of healthcare. However, unfortunately their implementation contiues to fail. Although there are several reasons for this, in this study a lack of project quality management is viewed as a key contributor to the failure of e-health solutions implementation projects in rural hospitals. This results in neglected aspects of quality assurance (QA), which forms an integral part of project quality management. The purpose of this study is to develop a Genertic Quality Assurance Model (GQAM) for the successful acquisition (i.e. development and implementation) of e-health solutions in rural hospitals in the Eastern Cape Province to enable improved quality of care and service delivery. In order to develop and test this model it was necessary to identify the QA methodologies that are currently used in rural hospitals and to evaluate their strengths and weaknesses, as well as their impact on project success. The study is divided into four phases; in each phase different study designs were followed. The study used triangulation of qualitative and some elements of quantitative research approaches, in terms of which a case study approach was adpoted to answer the research questions. This study did indeed develop a GQAM that can be used to ensure e-health solution success in rural hospitals. Furthermore, to aid in the implementation of this model, a set of QA value chain implementation guidelines were developed, as a framework, to inject the nodel into typical (SDLC) phases.
- 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 depiction of female characters by male writers in selected isiXhosa drama works
- Authors: Peter, Zola Welcome
- Date: 2010
- Subjects: Xhosa drama -- 20th century -- History and criticism , Women in literature , Feminism and literature , Xhosa drama -- Male authors , Gender identity in literature
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8446 , http://hdl.handle.net/10948/1482 , Xhosa drama -- 20th century -- History and criticism , Women in literature , Feminism and literature , Xhosa drama -- Male authors , Gender identity in literature
- Description: This research expresses female character portrayal in various drama works written by males. Chapter one is a general introduction that gives the key to this study, the motivation that leads to the selection of this topic; a literary review on the portrayal of female characters in literary works written by males; the scope of study, the basic composition of the ensuing chapters and the definitions of terms that are of paramount importance for this research. Various literary theories are used in Chapter two for the analysis of the research texts. These literary theories include womanism, gender and feminism which expose the social effects caused by the negative perception of females in social life and the negative portrayal of female characters in male dramatic writings. Other literary theories include onomastics as a literary theory, which exposes the relationship between the name giver of a person and the power the name gives to its bearer, as well as psychoanalysis as a theory which proved to be unavoidable, since this study analyses the personal behaviour of the individual characters within their literary environment. Chapter three depicts the general victimization of female characters in male drama works and exposes the various effects of the attitudes of male writers towards female characters in terms of gender role. Chapter four shows a general stereotypical portrayal of female characters in male written drama texts. This chapter shows the impact of stereotyping on female characters from drama works that puts them in a vulnerable position, showing that it is risky to become a victim of ill-treatment in their communities and the literary world. Chapter five deals with the psychological literary review of female characters, showing them as being suicidal and murderers who easily take their own lives and those of other people. Chapter six is a general conclusion of the works which includes observer remarks from other literary researchers of the literature.
- Full Text:
- Date Issued: 2010
- Authors: Peter, Zola Welcome
- Date: 2010
- Subjects: Xhosa drama -- 20th century -- History and criticism , Women in literature , Feminism and literature , Xhosa drama -- Male authors , Gender identity in literature
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8446 , http://hdl.handle.net/10948/1482 , Xhosa drama -- 20th century -- History and criticism , Women in literature , Feminism and literature , Xhosa drama -- Male authors , Gender identity in literature
- Description: This research expresses female character portrayal in various drama works written by males. Chapter one is a general introduction that gives the key to this study, the motivation that leads to the selection of this topic; a literary review on the portrayal of female characters in literary works written by males; the scope of study, the basic composition of the ensuing chapters and the definitions of terms that are of paramount importance for this research. Various literary theories are used in Chapter two for the analysis of the research texts. These literary theories include womanism, gender and feminism which expose the social effects caused by the negative perception of females in social life and the negative portrayal of female characters in male dramatic writings. Other literary theories include onomastics as a literary theory, which exposes the relationship between the name giver of a person and the power the name gives to its bearer, as well as psychoanalysis as a theory which proved to be unavoidable, since this study analyses the personal behaviour of the individual characters within their literary environment. Chapter three depicts the general victimization of female characters in male drama works and exposes the various effects of the attitudes of male writers towards female characters in terms of gender role. Chapter four shows a general stereotypical portrayal of female characters in male written drama texts. This chapter shows the impact of stereotyping on female characters from drama works that puts them in a vulnerable position, showing that it is risky to become a victim of ill-treatment in their communities and the literary world. Chapter five deals with the psychological literary review of female characters, showing them as being suicidal and murderers who easily take their own lives and those of other people. Chapter six is a general conclusion of the works which includes observer remarks from other literary researchers of the literature.
- 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 of a technology-strategy framework to improve the competitiveness of small-to medium-sized furniture manufacturers in South Africa
- Authors: Lourens, Ann Sharon
- Date: 2010
- Subjects: Furniture industry and trade -- Effect of technological innnovations on -- South Africa , Furniture industry and trade -- Economic aspects -- South Africa , Technology strategy , Competition
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8658 , http://hdl.handle.net/10948/1329 , Furniture industry and trade -- Effect of technological innnovations on -- South Africa , Furniture industry and trade -- Economic aspects -- South Africa , Technology strategy , Competition
- Description: The research problem addressed in this study was to establish how small- to medium-sized furniture manufacturing businesses could develop a technology strategy that would improve their competitiveness. Therefore, the primary objective of this research study was to develop a technology-strategy framework for small- to medium-sized furniture manufacturers to assist them to improve their competitiveness. Research has indicated that small- to medium-sized furniture manufacturers have the potential to contribute to South Africa‟s economic growth, job creation and gross domestic product. However, research has also indicated that small- to medium-sized furniture manufacturing industries have not kept up with technology developments and, as a result, competiveness is on the decline. Low-technology businesses, such as those found within the furniture manufacturing industry, often have no framework or methodology to guide the successful acquisition and integration of technology to enable a more competitive business. The main problem was addressed in three phases. Firstly, a literature review of strategy and technology-related factors was conducted which provided valuable insight into the development of a strategic framework. This included identification of the business strategy, external and internal factors influencing technology requirements, technology integration, -selection and criterion for competitiveness. Secondly, an empirical study consisting of both a quantitative and qualitative investigation was performed. The quantitative measuring instrument used was a questionnaire designed from the literature study information and was administered to a stratified sample of small- to medium-sized furniture manufacturers. The quantitative results were triangulated by qualitative interviews with selected respondents. The empirical results revealed a strong relationship between technology and competitiveness (as measured by business performance and technology- iv competitive advantage), thereby confirming the importance of technology utilisation for small- to medium-sized furniture manufacturers and the significance of developing a technology-strategy framework. Thirdly, by combining the literature study information and findings from the empirical investigation, the technology-strategy framework was developed. The technology-strategy framework provides a roadmap to integrate technology with the business strategy. The technology-strategy framework is used in three phases, firstly, the business strategy is identified, secondly, the technology-strategy framework provides a guide to identify and forecast technology, conduct an internal audit and identify technology that can execute the business strategy. The final phase is the application of criteria by means of which competitiveness improvement is assessed. Ultimately, the technology-strategy framework can facilitate improved competitiveness of the furniture industry.
- Full Text:
- Date Issued: 2010
- Authors: Lourens, Ann Sharon
- Date: 2010
- Subjects: Furniture industry and trade -- Effect of technological innnovations on -- South Africa , Furniture industry and trade -- Economic aspects -- South Africa , Technology strategy , Competition
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8658 , http://hdl.handle.net/10948/1329 , Furniture industry and trade -- Effect of technological innnovations on -- South Africa , Furniture industry and trade -- Economic aspects -- South Africa , Technology strategy , Competition
- Description: The research problem addressed in this study was to establish how small- to medium-sized furniture manufacturing businesses could develop a technology strategy that would improve their competitiveness. Therefore, the primary objective of this research study was to develop a technology-strategy framework for small- to medium-sized furniture manufacturers to assist them to improve their competitiveness. Research has indicated that small- to medium-sized furniture manufacturers have the potential to contribute to South Africa‟s economic growth, job creation and gross domestic product. However, research has also indicated that small- to medium-sized furniture manufacturing industries have not kept up with technology developments and, as a result, competiveness is on the decline. Low-technology businesses, such as those found within the furniture manufacturing industry, often have no framework or methodology to guide the successful acquisition and integration of technology to enable a more competitive business. The main problem was addressed in three phases. Firstly, a literature review of strategy and technology-related factors was conducted which provided valuable insight into the development of a strategic framework. This included identification of the business strategy, external and internal factors influencing technology requirements, technology integration, -selection and criterion for competitiveness. Secondly, an empirical study consisting of both a quantitative and qualitative investigation was performed. The quantitative measuring instrument used was a questionnaire designed from the literature study information and was administered to a stratified sample of small- to medium-sized furniture manufacturers. The quantitative results were triangulated by qualitative interviews with selected respondents. The empirical results revealed a strong relationship between technology and competitiveness (as measured by business performance and technology- iv competitive advantage), thereby confirming the importance of technology utilisation for small- to medium-sized furniture manufacturers and the significance of developing a technology-strategy framework. Thirdly, by combining the literature study information and findings from the empirical investigation, the technology-strategy framework was developed. The technology-strategy framework provides a roadmap to integrate technology with the business strategy. The technology-strategy framework is used in three phases, firstly, the business strategy is identified, secondly, the technology-strategy framework provides a guide to identify and forecast technology, conduct an internal audit and identify technology that can execute the business strategy. The final phase is the application of criteria by means of which competitiveness improvement is assessed. Ultimately, the technology-strategy framework can facilitate improved competitiveness of the furniture industry.
- Full Text:
- Date Issued: 2010
The impact of child sexual abuse (CSA) on the school life experiences and academic performance of adult CSA survivors
- Ah Hing, Antoinette Danielle
- Authors: Ah Hing, Antoinette Danielle
- Date: 2010
- Subjects: Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9478 , http://hdl.handle.net/10948/1259 , Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Description: Child Sexual Abuse (CSA) is a societal problem whose origins date back to the times of the ancient Greeks and Romans. It is found in all levels of society, from the wealthiest to the poorest; and the short-term and long-term impacts it has on the lives of the victims, can be devastating. There are many reasons for the occurrence of child sexual abuse, but in all cases, the ultimate accountability rests on the shoulders of the sexual offender. The nature of child sexual victimisation varies from verbal suggestions to violent physical force. Irrespective of which type the child is being subjected to, as the weaker partner in the pedagogical relationship with the adult, s/he is never able to defend herself/himself. The global phenomenon, and the increase in CSA, has given rise to the research question, namely: How does child sexual abuse impact on the school life experiences and academic performance of learners at school? The purpose of this research study was to provide insight into the following issues: • The nature and identification of the symptoms of child sexual abuse; • The manner in which sexually abused children manifest their experiences of sexual abuse at school; • How sexually abused children cope with their learning tasks; and • Recommendations for educators. The literature relating to CSA was reviewed, with the aim of establishing a solid theoretical foundation for the study. CSA has been looked at holistically, encompassing the accepted definitions, the related concepts, the nature of sexual abuse, the prevalence and incidence of CSA, the possible causes, the short-term and long-term impacts, and the suggestions by adult survivors for use by educators in their efforts to help abused learners. 11 In an attempt to provide acceptable answers to the research problem, a mixed- method research design was implemented. The research study was conducted in two phases: Stage 1 consisted of an exploration of the research problem by means of the following question put to the participants: In your experience as an adult survivor of child sexual abuse how did the abuse impact on your school life experiences, including your academic performance? A total of nineteen participants from the Eastern Cape Province shared their experiences, by means of writing their life story as a narrative. Purposive and availability sampling of adult survivors was undertaken. In order to ensure the trustworthiness and authenticity of the research methodology, Guba’s model of data verification was used. Accepted ethical measures were taken into consideration and adhered to during the research. The analysed data were taken directly from the narratives that the individual participants saved onto flashdrives. Consensus by the researcher and coder was reached regarding the identification of themes, categories and subcategories. The following four significant themes emerged, based on the results of the data analysis: Theme One: Health, sexuality and the sexual experiences of sexual abused children and adolescents. Theme Two: The social development of sexually abused children and adolescents. Theme Three: School-related experiences and academic performance of sexually abused children and adolescents. Theme Four: Advice and suggestions from adult survivors for young victims of CSA. 12 Stage 2 offered recommendations to the teachers of learners who are, or have been sexually abused, derived from the findings of Phase 1. The conclusion was reached that CSA does have an impact on the academic performance of learners. Therefore, teachers are in need of a greater understanding and awareness of CSA, in order to help these learners.
- Full Text:
- Date Issued: 2010
- Authors: Ah Hing, Antoinette Danielle
- Date: 2010
- Subjects: Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9478 , http://hdl.handle.net/10948/1259 , Child sexual abuse , Adult child sexual abuse victims -- Counseling of , Sexually abused children , Academic achievement
- Description: Child Sexual Abuse (CSA) is a societal problem whose origins date back to the times of the ancient Greeks and Romans. It is found in all levels of society, from the wealthiest to the poorest; and the short-term and long-term impacts it has on the lives of the victims, can be devastating. There are many reasons for the occurrence of child sexual abuse, but in all cases, the ultimate accountability rests on the shoulders of the sexual offender. The nature of child sexual victimisation varies from verbal suggestions to violent physical force. Irrespective of which type the child is being subjected to, as the weaker partner in the pedagogical relationship with the adult, s/he is never able to defend herself/himself. The global phenomenon, and the increase in CSA, has given rise to the research question, namely: How does child sexual abuse impact on the school life experiences and academic performance of learners at school? The purpose of this research study was to provide insight into the following issues: • The nature and identification of the symptoms of child sexual abuse; • The manner in which sexually abused children manifest their experiences of sexual abuse at school; • How sexually abused children cope with their learning tasks; and • Recommendations for educators. The literature relating to CSA was reviewed, with the aim of establishing a solid theoretical foundation for the study. CSA has been looked at holistically, encompassing the accepted definitions, the related concepts, the nature of sexual abuse, the prevalence and incidence of CSA, the possible causes, the short-term and long-term impacts, and the suggestions by adult survivors for use by educators in their efforts to help abused learners. 11 In an attempt to provide acceptable answers to the research problem, a mixed- method research design was implemented. The research study was conducted in two phases: Stage 1 consisted of an exploration of the research problem by means of the following question put to the participants: In your experience as an adult survivor of child sexual abuse how did the abuse impact on your school life experiences, including your academic performance? A total of nineteen participants from the Eastern Cape Province shared their experiences, by means of writing their life story as a narrative. Purposive and availability sampling of adult survivors was undertaken. In order to ensure the trustworthiness and authenticity of the research methodology, Guba’s model of data verification was used. Accepted ethical measures were taken into consideration and adhered to during the research. The analysed data were taken directly from the narratives that the individual participants saved onto flashdrives. Consensus by the researcher and coder was reached regarding the identification of themes, categories and subcategories. The following four significant themes emerged, based on the results of the data analysis: Theme One: Health, sexuality and the sexual experiences of sexual abused children and adolescents. Theme Two: The social development of sexually abused children and adolescents. Theme Three: School-related experiences and academic performance of sexually abused children and adolescents. Theme Four: Advice and suggestions from adult survivors for young victims of CSA. 12 Stage 2 offered recommendations to the teachers of learners who are, or have been sexually abused, derived from the findings of Phase 1. The conclusion was reached that CSA does have an impact on the academic performance of learners. Therefore, teachers are in need of a greater understanding and awareness of CSA, in order to help these learners.
- Full Text:
- Date Issued: 2010
The impact of the Western conceptualization of the Christian gospel on its communication in a non-Western environment, with particular reference to the AmaXhosa
- Authors: Higgs, Michael John
- Date: 2010
- Subjects: Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Language: English
- Type: Thesis , Doctoral , D Th
- Identifier: vital:11800 , http://hdl.handle.net/10353/356 , Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Description: This thesis examines the extent and nature of the impact of the contextualization of Christianity upon the amaXhosa from the missionary irruption in the nineteenth century to the present day, and proceeds to examine the implications of this impact for the presentation of the Christian gospel in the contemporary Eastern Cape. Chapter One describes the problem, offers definitions of key concepts and outlines the procedural method for the rest of the thesis. Chapter Two deals with the question of the cross-cultural communication of the Christian gospel in theory. Doctrinal questions such as the nature of the gospel are examined. The basic hermeneutical issue of the categorization of doctrinal tenets according to whether they are required or simply permitted is discussed in terms of Osborne's categories: 'cardinal', 'non-cardinal'. Tenets which are found to be 'anti-scriptural' would be rejected. Specific hermeneutical topics such as language and meaning, symbolics, textuality and orality are then discussed. This is followed by a survey of secular influences which affect a conceptualization. This chapter is preparatory to, and definitive for, the discourse which follows. Chapter Three outlines the cultural heritage from which the Western missionary contextualization of Christianity developed. It shows the extent to which this presentation of the gospel was dependent upon the philosophy which Britain and Europe inherited from the classical Greek culture. More modern developments such as the Enlightenment, Empiricism and Historicism bring the discourse up to the point at which the missionaries arrived. Chapter Four deals with the initial encounter between the missionaries and the amaXhosa. A brief account is given of the nature of the religious and spiritual aspects of the Xhosa culture which first encountered Christianity. The doctrinal section of this chapter deals with those doctrines in the missionary message which became issues for the amaXhosa. The hermeneutical section shows how the cultural setting of the West (vii) affected both the contextualization by the missionaries and the conceptualization by the amaXhosa. To a large extent, the missionaries made the double mistake of imposing their culture on the amaXhosa and failing to accord respect, even recognition, to the Xhosa culture. This amounted to imperialism, which, together with the political imperialism of Britain as the colonizing power, evoked responses from the Xhosa community which are outlined in section 4.4, including those of Nxele and Ntsikana. Because the impact of the Western contextualization is an on-going phenomenon, the thesis continues to trace its development up to the present time. Apartheid is briefly mentioned in Chapter Five. The point is made that all white people were perceived by the amaXhosa to be Christians, and the architects and practitioners of apartheid claimed to be Christians. This ideology therefore had a direct effect on the Xhosa conceptualization of the gospel. The architects of apartheid actually believed that they were accepting God's gift and mandate. This chapter includes Black theological reaction to apartheid in terms of the South African version of Liberation theology. Chapter Six returns to Western Theology in order to bring the sphere of discourse from the point at which it left off at the end of Chapter Three up to the present time. The schools of thought in this period are: Secularism and Existentialism, together with their theological extension, Demythologization. The main religious movements are the Charismatic Movement and Neo-Pentecostalism. Postmodernism came as a later philosophical school, to be followed by Globality. Chapter Seven deals with black South African reactive and proactive responses. The predominant theologies are those of Dwane, Buthelezi, Boesak and Mtuze. Although Dwane, Buthelezi and Boesak came on the scene at the same time as the black theologians reviewed in Chapter Five, their work is placed here because it differs significantly from the more radical responses of the latter. Mtuze is post-apartheid, and responds to the developments outlined in Chapter Six. Chapter Eight draws the findings of the thesis together, by considering how the Christian Gospel ought to be presented to the various contemporary sub-cultures of the amaXhosa. (viii) The last Chapter applies the findings of the thesis to the task in hand. The desired outcomes are listed and briefly discussed. The task ahead is enunciated in terms of manpower and other resources for the effective communication of the Christian gospel in the twenty-first century. The past, present and projected programmes of the Bible Institute Eastern Cape [the target institution] are described and assessed. Finally, topics which presented themselves in the course of the preparation of this thesis are suggested for future research.
- Full Text:
- Date Issued: 2010
- Authors: Higgs, Michael John
- Date: 2010
- Subjects: Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Language: English
- Type: Thesis , Doctoral , D Th
- Identifier: vital:11800 , http://hdl.handle.net/10353/356 , Christianity and culture -- South Africa , Church history , Missions -- South Africa -- Eastern Cape , Xhosa (African people) -- Religion , Communication -- Religious aspects -- Christianity
- Description: This thesis examines the extent and nature of the impact of the contextualization of Christianity upon the amaXhosa from the missionary irruption in the nineteenth century to the present day, and proceeds to examine the implications of this impact for the presentation of the Christian gospel in the contemporary Eastern Cape. Chapter One describes the problem, offers definitions of key concepts and outlines the procedural method for the rest of the thesis. Chapter Two deals with the question of the cross-cultural communication of the Christian gospel in theory. Doctrinal questions such as the nature of the gospel are examined. The basic hermeneutical issue of the categorization of doctrinal tenets according to whether they are required or simply permitted is discussed in terms of Osborne's categories: 'cardinal', 'non-cardinal'. Tenets which are found to be 'anti-scriptural' would be rejected. Specific hermeneutical topics such as language and meaning, symbolics, textuality and orality are then discussed. This is followed by a survey of secular influences which affect a conceptualization. This chapter is preparatory to, and definitive for, the discourse which follows. Chapter Three outlines the cultural heritage from which the Western missionary contextualization of Christianity developed. It shows the extent to which this presentation of the gospel was dependent upon the philosophy which Britain and Europe inherited from the classical Greek culture. More modern developments such as the Enlightenment, Empiricism and Historicism bring the discourse up to the point at which the missionaries arrived. Chapter Four deals with the initial encounter between the missionaries and the amaXhosa. A brief account is given of the nature of the religious and spiritual aspects of the Xhosa culture which first encountered Christianity. The doctrinal section of this chapter deals with those doctrines in the missionary message which became issues for the amaXhosa. The hermeneutical section shows how the cultural setting of the West (vii) affected both the contextualization by the missionaries and the conceptualization by the amaXhosa. To a large extent, the missionaries made the double mistake of imposing their culture on the amaXhosa and failing to accord respect, even recognition, to the Xhosa culture. This amounted to imperialism, which, together with the political imperialism of Britain as the colonizing power, evoked responses from the Xhosa community which are outlined in section 4.4, including those of Nxele and Ntsikana. Because the impact of the Western contextualization is an on-going phenomenon, the thesis continues to trace its development up to the present time. Apartheid is briefly mentioned in Chapter Five. The point is made that all white people were perceived by the amaXhosa to be Christians, and the architects and practitioners of apartheid claimed to be Christians. This ideology therefore had a direct effect on the Xhosa conceptualization of the gospel. The architects of apartheid actually believed that they were accepting God's gift and mandate. This chapter includes Black theological reaction to apartheid in terms of the South African version of Liberation theology. Chapter Six returns to Western Theology in order to bring the sphere of discourse from the point at which it left off at the end of Chapter Three up to the present time. The schools of thought in this period are: Secularism and Existentialism, together with their theological extension, Demythologization. The main religious movements are the Charismatic Movement and Neo-Pentecostalism. Postmodernism came as a later philosophical school, to be followed by Globality. Chapter Seven deals with black South African reactive and proactive responses. The predominant theologies are those of Dwane, Buthelezi, Boesak and Mtuze. Although Dwane, Buthelezi and Boesak came on the scene at the same time as the black theologians reviewed in Chapter Five, their work is placed here because it differs significantly from the more radical responses of the latter. Mtuze is post-apartheid, and responds to the developments outlined in Chapter Six. Chapter Eight draws the findings of the thesis together, by considering how the Christian Gospel ought to be presented to the various contemporary sub-cultures of the amaXhosa. (viii) The last Chapter applies the findings of the thesis to the task in hand. The desired outcomes are listed and briefly discussed. The task ahead is enunciated in terms of manpower and other resources for the effective communication of the Christian gospel in the twenty-first century. The past, present and projected programmes of the Bible Institute Eastern Cape [the target institution] are described and assessed. Finally, topics which presented themselves in the course of the preparation of this thesis are suggested for future research.
- Full Text:
- Date Issued: 2010
The in vitro biological activities of three Hypoxis species and their active compounds
- Authors: Boukes, Gerhardt Johannes
- Date: 2010
- Subjects: Potatoes -- Africa , Potatoes -- Therapeutic use , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10322 , http://hdl.handle.net/10948/1228 , Potatoes -- Africa , Potatoes -- Therapeutic use , Medicinal plants
- Description: The African potato is used as an African traditional medicine for its nutritional and medicinal properties. Most research has been carried out on H. hemerocallidea, with very little or nothing on other Hypoxis spp. The main aim of this project was to provide scientific data on the anticancer, anti-inflammatory and antioxidant properties of H. hemerocallidea, H. stellipilis and H. sobolifera chloroform extracts and their active compounds. The hypoxoside and phytosterol contents of the three Hypoxis spp. were determined using TLC, HPLC and GC. H. hemerocallidea and H. sobolifera chloroform extracts contained the highest amounts of hypoxoside and β-sitosterol, respectively. For the anticancer properties, cytotoxicity of the Hypoxis extracts and its purified compounds were determined against the HeLa, HT-29 and MCF-7 cancer cell lines (using MTT), and PBMCs (using CellTiter-Blue®). H. sobolifera had the best cytotoxicity against the three cancer cell lines, whereas H. stellipilis stimulated HeLa and HT-29 cancer cell growth. IC50 values of hypoxoside and rooperol were determined. DNA cell cycle arrest (using PI staining) occurred in the late G1/early S (confirmed by increased p21Waf1/Cip1 expression) and G2/M phases after 15 and 48 hrs, respectively, when treated with Hypoxis extracts and rooperol. H. sobolifera and rooperol activated caspase-3 and -7 (using fluorescently labelled antibodies) in HeLa and HT-29 cancer cells, and caspase-7 in MCF-7 cancer cells after 48 hrs. Annexin V binding to phosphatidylserines in rooperol treated U937 cells confirmed early apoptosis after 15 hrs. The TUNEL assay showed DNA fragmentation in the three cancer cell lines when treated with H. sobolifera and rooperol for 48 hrs. A shift pass the G2/M phase has led to the investigation of endoreduplication, which was confirmed by cell/nucleus size, and anti-apoptotic proteins (Akt, phospho-Akt, phospho-Bcl-2 and p21Waf1/Cip1). U937 cell differentiation to monocyte-macrophages was optimized using PMA and 1,25(OH)2D3, which was confirmed by morphological and biochemical changes. For the anti-inflammatory properties, Hypoxis extracts and rooperol significantly increased NO production in monocyte-macrophages (pre-loaded with DAF-2 DA) and phagocytosis of pHrodoTM E. coli BioParticles®. The treatments had no effect on COX-2 expression in monocyte-macrophages. The phytosterols significantly increased IL-1β and IL-6 secretion xv (using the FlowCytomix Multiplex human Th1/Th2 10plex Kit I) in the PBMCs of one donor. For the antioxidant properties, Hypoxis extracts and rooperol significantly increased ROS production in undifferentiated and differentiated U937 cells, which were pre-loaded with DCFH-DA. Hypoxis extracts and purified compounds had ferric reducing activities, but only rooperol had ferric reducing activities significantly greater than ascorbic acid. β-sitosterol, campesterol and cholesterol significantly increased SOD activity in Chang liver cells, while H. stellipilis, H. sobolifera and rooperol decreased SOD activity. Anticancer, anti-inflammatory and antioxidant properties of the Hypoxis extracts may be attributed to the β-sitosterol content, because Hypoxis chloroform extracts contained very little or no hypoxoside. Unidentified compounds, and synergistic and additive effects of the compounds may have contributed to the biological effects. This study confirms previous reports that rooperol is the active compound. Results provide scientific data on the medicinal properties of one of the most frequently used medicinal plants in South Africa.
- Full Text:
- Date Issued: 2010
- Authors: Boukes, Gerhardt Johannes
- Date: 2010
- Subjects: Potatoes -- Africa , Potatoes -- Therapeutic use , Medicinal plants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10322 , http://hdl.handle.net/10948/1228 , Potatoes -- Africa , Potatoes -- Therapeutic use , Medicinal plants
- Description: The African potato is used as an African traditional medicine for its nutritional and medicinal properties. Most research has been carried out on H. hemerocallidea, with very little or nothing on other Hypoxis spp. The main aim of this project was to provide scientific data on the anticancer, anti-inflammatory and antioxidant properties of H. hemerocallidea, H. stellipilis and H. sobolifera chloroform extracts and their active compounds. The hypoxoside and phytosterol contents of the three Hypoxis spp. were determined using TLC, HPLC and GC. H. hemerocallidea and H. sobolifera chloroform extracts contained the highest amounts of hypoxoside and β-sitosterol, respectively. For the anticancer properties, cytotoxicity of the Hypoxis extracts and its purified compounds were determined against the HeLa, HT-29 and MCF-7 cancer cell lines (using MTT), and PBMCs (using CellTiter-Blue®). H. sobolifera had the best cytotoxicity against the three cancer cell lines, whereas H. stellipilis stimulated HeLa and HT-29 cancer cell growth. IC50 values of hypoxoside and rooperol were determined. DNA cell cycle arrest (using PI staining) occurred in the late G1/early S (confirmed by increased p21Waf1/Cip1 expression) and G2/M phases after 15 and 48 hrs, respectively, when treated with Hypoxis extracts and rooperol. H. sobolifera and rooperol activated caspase-3 and -7 (using fluorescently labelled antibodies) in HeLa and HT-29 cancer cells, and caspase-7 in MCF-7 cancer cells after 48 hrs. Annexin V binding to phosphatidylserines in rooperol treated U937 cells confirmed early apoptosis after 15 hrs. The TUNEL assay showed DNA fragmentation in the three cancer cell lines when treated with H. sobolifera and rooperol for 48 hrs. A shift pass the G2/M phase has led to the investigation of endoreduplication, which was confirmed by cell/nucleus size, and anti-apoptotic proteins (Akt, phospho-Akt, phospho-Bcl-2 and p21Waf1/Cip1). U937 cell differentiation to monocyte-macrophages was optimized using PMA and 1,25(OH)2D3, which was confirmed by morphological and biochemical changes. For the anti-inflammatory properties, Hypoxis extracts and rooperol significantly increased NO production in monocyte-macrophages (pre-loaded with DAF-2 DA) and phagocytosis of pHrodoTM E. coli BioParticles®. The treatments had no effect on COX-2 expression in monocyte-macrophages. The phytosterols significantly increased IL-1β and IL-6 secretion xv (using the FlowCytomix Multiplex human Th1/Th2 10plex Kit I) in the PBMCs of one donor. For the antioxidant properties, Hypoxis extracts and rooperol significantly increased ROS production in undifferentiated and differentiated U937 cells, which were pre-loaded with DCFH-DA. Hypoxis extracts and purified compounds had ferric reducing activities, but only rooperol had ferric reducing activities significantly greater than ascorbic acid. β-sitosterol, campesterol and cholesterol significantly increased SOD activity in Chang liver cells, while H. stellipilis, H. sobolifera and rooperol decreased SOD activity. Anticancer, anti-inflammatory and antioxidant properties of the Hypoxis extracts may be attributed to the β-sitosterol content, because Hypoxis chloroform extracts contained very little or no hypoxoside. Unidentified compounds, and synergistic and additive effects of the compounds may have contributed to the biological effects. This study confirms previous reports that rooperol is the active compound. Results provide scientific data on the medicinal properties of one of the most frequently used medicinal plants in South Africa.
- Full Text:
- Date Issued: 2010
The influence of emotional intelligence on change management strategies in establishing self-managing schools : a multi-site case study
- Authors: Pather, S. S
- Date: 2010
- Subjects: Emotional intelligence -- South Africa , Self-directed work teams -- South Africa , Schools -- Decentralization -- South Africa , Change -- Management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9554 , http://hdl.handle.net/10948/1154 , Emotional intelligence -- South Africa , Self-directed work teams -- South Africa , Schools -- Decentralization -- South Africa , Change -- Management
- Description: In South Africa, the trend has been towards the decentralising of authority and giving greater powers to schools. This implies the active involvement of the school governing body members, the school management team members and the Level One educators in the day-to-day functioning of the school. Whilst some schools have welcomed this change and seen this devolution of power as an added advantage contributing to the efficacy of schools, some schools have struggled, while others have failed dismally to cope with this added responsibility of managing their own resources. The researcher, being an educator involved in this transition, has been intrigued by the success of some self-managing schools and the failure of others. The following words of Oliver Wendell Holmes have inspired the investigator to conduct this research to ascertain the reasons for the success of certain schools and the failure of others: “What lies behind us and what lies before us are tiny matters compared to what lies within us.” Since the performance of schools is normally ranked according to their matriculation pass rates, this research focused on six self-managing schools in the Port Elizabeth District. These schools were selected on the basis of their matriculation performances in 2008. Two of the schools had achieved an above 85 percent matriculation pass rate (Category A); two obtained a 50 percent pass rate (Category B); while the other two schools obtained matriculation pass rates of between 25 percent and 30 percent (Category C). Although the research relied strongly on a qualitative method of inquiry, because of the nature of the data and the need to obtain a better understanding of the feelings, attitude and perceptions of those in management positions, governing body positions and members of the personnel, multiple instruments for data collection such as a literature review and the study of school documents and questionnaires, were used. This inclusion of these multiple instruments for obtaining information, which is also called triangulation, contributed to the reliability and validity of the empirical investigation. Although the data was presented in the form of tables and graphs, vi which alludes to a quantitative approach, a narrative interpretation of the findings, which is associated with a qualitative method of inquiry, was also presented. An analysis of the findings revealed that there was a great amount of involvement of the principals, school management team members and Level One educators in Category A schools, which had a matriculation pass rate of above 85%, in the following change management strategies: the establishment of a vision, planning and organising, teamwork, training and development, communication, praise and incentives, and evaluation and feedback. There was also a great contribution by the school governing body members. However, the study revealed that Category B and Category C schools did not effectively use communication, praise and incentives and evaluation and feedback as change management strategies. It was evident from the empirical investigation that in Category B and C schools, the school governing body members were less, or not involved in the usage of the change management strategies applied. According to the results based on the six-facet model of Emotional Intelligence, Category A schools obtained 80% and above in the competencies relating to the self and social domain. Category B schools fluctuated between 50 percent and 80 percent in both dimensions, while Category C schools fluctuated between 30 percent and 80 percent. The findings suggest that there should be greater involvement of all stakeholders, especially the school governing body members, in the establishment of a vision, planning and organising, communication, teamwork, training and development, praise and incentives and the provision of feedback and evaluation for self-managing schools to become effective and improve their performances. Professional development, especially in the areas pertaining to Emotional Intelligence competencies such as personal and interpersonal skills, should be prioritised. This thesis proposes that, on the basis of the investigation carried out at the six participating schools on the influence of Emotional Intelligence on the change management strategies adopted in self-managing schools, schools use strategies such as the establishment of a vision, planning and organising, communication, teamwork, training and development, praise and incentives and evaluation and feedback to ameliorate the damaging impact of change. There should be continuous training and development at schools, especially for the school governing body members, who are elected every three years. The newly elected school governing body members need to develop the necessary skills to effectively contribute to the efficacy of schools. The human resource is the vital ingredient in schools, thus for any progression or improvement, all stakeholders need to be informed, trained and enriched. Since Emotional Intelligence can be learned, professional development in the area of Emotional Intelligence should be given more thought and included in training courses, focusing on the development of personal and interpersonal skills. The Emotional Intelligence training should be conducted as part of teacher training courses as well as on an annual basis for educators already in the teaching system, since Emotional Intelligence can influence the use of change management strategies at schools and enhance the efficacy of the functioning of self-managing schools.
- Full Text:
- Date Issued: 2010
- Authors: Pather, S. S
- Date: 2010
- Subjects: Emotional intelligence -- South Africa , Self-directed work teams -- South Africa , Schools -- Decentralization -- South Africa , Change -- Management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9554 , http://hdl.handle.net/10948/1154 , Emotional intelligence -- South Africa , Self-directed work teams -- South Africa , Schools -- Decentralization -- South Africa , Change -- Management
- Description: In South Africa, the trend has been towards the decentralising of authority and giving greater powers to schools. This implies the active involvement of the school governing body members, the school management team members and the Level One educators in the day-to-day functioning of the school. Whilst some schools have welcomed this change and seen this devolution of power as an added advantage contributing to the efficacy of schools, some schools have struggled, while others have failed dismally to cope with this added responsibility of managing their own resources. The researcher, being an educator involved in this transition, has been intrigued by the success of some self-managing schools and the failure of others. The following words of Oliver Wendell Holmes have inspired the investigator to conduct this research to ascertain the reasons for the success of certain schools and the failure of others: “What lies behind us and what lies before us are tiny matters compared to what lies within us.” Since the performance of schools is normally ranked according to their matriculation pass rates, this research focused on six self-managing schools in the Port Elizabeth District. These schools were selected on the basis of their matriculation performances in 2008. Two of the schools had achieved an above 85 percent matriculation pass rate (Category A); two obtained a 50 percent pass rate (Category B); while the other two schools obtained matriculation pass rates of between 25 percent and 30 percent (Category C). Although the research relied strongly on a qualitative method of inquiry, because of the nature of the data and the need to obtain a better understanding of the feelings, attitude and perceptions of those in management positions, governing body positions and members of the personnel, multiple instruments for data collection such as a literature review and the study of school documents and questionnaires, were used. This inclusion of these multiple instruments for obtaining information, which is also called triangulation, contributed to the reliability and validity of the empirical investigation. Although the data was presented in the form of tables and graphs, vi which alludes to a quantitative approach, a narrative interpretation of the findings, which is associated with a qualitative method of inquiry, was also presented. An analysis of the findings revealed that there was a great amount of involvement of the principals, school management team members and Level One educators in Category A schools, which had a matriculation pass rate of above 85%, in the following change management strategies: the establishment of a vision, planning and organising, teamwork, training and development, communication, praise and incentives, and evaluation and feedback. There was also a great contribution by the school governing body members. However, the study revealed that Category B and Category C schools did not effectively use communication, praise and incentives and evaluation and feedback as change management strategies. It was evident from the empirical investigation that in Category B and C schools, the school governing body members were less, or not involved in the usage of the change management strategies applied. According to the results based on the six-facet model of Emotional Intelligence, Category A schools obtained 80% and above in the competencies relating to the self and social domain. Category B schools fluctuated between 50 percent and 80 percent in both dimensions, while Category C schools fluctuated between 30 percent and 80 percent. The findings suggest that there should be greater involvement of all stakeholders, especially the school governing body members, in the establishment of a vision, planning and organising, communication, teamwork, training and development, praise and incentives and the provision of feedback and evaluation for self-managing schools to become effective and improve their performances. Professional development, especially in the areas pertaining to Emotional Intelligence competencies such as personal and interpersonal skills, should be prioritised. This thesis proposes that, on the basis of the investigation carried out at the six participating schools on the influence of Emotional Intelligence on the change management strategies adopted in self-managing schools, schools use strategies such as the establishment of a vision, planning and organising, communication, teamwork, training and development, praise and incentives and evaluation and feedback to ameliorate the damaging impact of change. There should be continuous training and development at schools, especially for the school governing body members, who are elected every three years. The newly elected school governing body members need to develop the necessary skills to effectively contribute to the efficacy of schools. The human resource is the vital ingredient in schools, thus for any progression or improvement, all stakeholders need to be informed, trained and enriched. Since Emotional Intelligence can be learned, professional development in the area of Emotional Intelligence should be given more thought and included in training courses, focusing on the development of personal and interpersonal skills. The Emotional Intelligence training should be conducted as part of teacher training courses as well as on an annual basis for educators already in the teaching system, since Emotional Intelligence can influence the use of change management strategies at schools and enhance the efficacy of the functioning of self-managing schools.
- Full Text:
- Date Issued: 2010
The integration of natural resource management into the curriculum of rural under-resourced schools : a Bernsteinian analysis
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2010
- Subjects: Conservation of natural resources -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa -- Eastern Cape Bernstein, Basil B Nature conservation -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4762 , http://hdl.handle.net/10962/d1007157
- Description: This study was motivated by the need to improve curriculum relevance in poor rural schools through contextualised teaching and learning based on the management of local natural resources. It involved four schools which are located in the Ngqunshwa Local Municipality of the Eastern Cape Province of South Africa. The study's aim was to provide insight into and better understanding of the curriculum implementation process regarding natural resource management (NRM) education in a poor rural education context. This was done by analysing the extent of NRM integration in pedagogic texts, activities and practices in the different fields which constitute the structure of the pedagogic system in this education sector. The study adopted an interpretivist approach to the analysis, which was based on indicators of the extent of NRM integration, and was informed by Bernstein's concepts of classification and curriculum recontextualisation, and his model of the structure of the pedagogic system. The items which were analysed included national and provincial Grade 10 Life Sciences curriculum documents, Grade 10 Life Sciences textbooks, in-service training workshops for Life Sciences teachers, and various school documents, activities and practices. The analysis also involved interviews with educators, and classroom observations of Grade 10 Life Sciences lessons. The results revealed a very high overall level of NRM integration in the Grade 10 Life Sciences curriculum documents produced at national and provincial levels. The overall level of NRM integration was also found to be very high in the Grade 10 Life Science textbooks that were analysed, but very low in the in-service teacher training workshops, and in the schools' documents, activities and practices, especially in the Grade 10 Life Sciences lessons, and in schools' end-of-year Grade 10 Life Sciences examination papers. The study makes a number of recommendations towards effective integration of NRM into the curriculum of Eastern Cape's rural poor schools which include more specific and explicit reference to NRM in the official Grade 10 Life Sciences curriculum documents, the provision of environmental education courses to district education staff and Grade 10 Life Sciences teachers, the training of teachers in the classroom use of textbooks and other educational materials, and regular monitoring of teachers' work. The study also exposes important knowledge gaps which need urgent research attention in order to enhance NRM education in the poor rural schools of the Eastern Cape. These include analysing power and control relationships between the various agencies and agents that are involved with curriculum implementation in this education sector, and conducting investigation into the creation of specialist NRM knowledge and into the quality of NRM knowledge that is transmitted as pedagogic discourse in schools. This study contributes to the fields of rural education and environmental education in South Africa, and to the growing interest in the study of curriculum from a sociology of education perspective in the context of the country’s post-apartheid curriculum reforms.
- Full Text:
- Date Issued: 2010
- Authors: Nsubuga, Yvonne Nakalo
- Date: 2010
- Subjects: Conservation of natural resources -- Study and teaching -- South Africa Environmental education -- Curricula -- South Africa -- Eastern Cape Bernstein, Basil B Nature conservation -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4762 , http://hdl.handle.net/10962/d1007157
- Description: This study was motivated by the need to improve curriculum relevance in poor rural schools through contextualised teaching and learning based on the management of local natural resources. It involved four schools which are located in the Ngqunshwa Local Municipality of the Eastern Cape Province of South Africa. The study's aim was to provide insight into and better understanding of the curriculum implementation process regarding natural resource management (NRM) education in a poor rural education context. This was done by analysing the extent of NRM integration in pedagogic texts, activities and practices in the different fields which constitute the structure of the pedagogic system in this education sector. The study adopted an interpretivist approach to the analysis, which was based on indicators of the extent of NRM integration, and was informed by Bernstein's concepts of classification and curriculum recontextualisation, and his model of the structure of the pedagogic system. The items which were analysed included national and provincial Grade 10 Life Sciences curriculum documents, Grade 10 Life Sciences textbooks, in-service training workshops for Life Sciences teachers, and various school documents, activities and practices. The analysis also involved interviews with educators, and classroom observations of Grade 10 Life Sciences lessons. The results revealed a very high overall level of NRM integration in the Grade 10 Life Sciences curriculum documents produced at national and provincial levels. The overall level of NRM integration was also found to be very high in the Grade 10 Life Science textbooks that were analysed, but very low in the in-service teacher training workshops, and in the schools' documents, activities and practices, especially in the Grade 10 Life Sciences lessons, and in schools' end-of-year Grade 10 Life Sciences examination papers. The study makes a number of recommendations towards effective integration of NRM into the curriculum of Eastern Cape's rural poor schools which include more specific and explicit reference to NRM in the official Grade 10 Life Sciences curriculum documents, the provision of environmental education courses to district education staff and Grade 10 Life Sciences teachers, the training of teachers in the classroom use of textbooks and other educational materials, and regular monitoring of teachers' work. The study also exposes important knowledge gaps which need urgent research attention in order to enhance NRM education in the poor rural schools of the Eastern Cape. These include analysing power and control relationships between the various agencies and agents that are involved with curriculum implementation in this education sector, and conducting investigation into the creation of specialist NRM knowledge and into the quality of NRM knowledge that is transmitted as pedagogic discourse in schools. This study contributes to the fields of rural education and environmental education in South Africa, and to the growing interest in the study of curriculum from a sociology of education perspective in the context of the country’s post-apartheid curriculum reforms.
- Full Text:
- Date Issued: 2010
The introduction of cyberhunts as a teaching and learning strategy to guide teachers towards the integration of computer technology in schools
- Authors: Du Plessis, André
- Date: 2010
- Subjects: Educational technology , Computers -- Study and teaching , Computer-assisted instruction , Competency-based education
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9555 , http://hdl.handle.net/10948/1210 , Educational technology , Computers -- Study and teaching , Computer-assisted instruction , Competency-based education
- Description: This study, which is based on a computer literacy teacher development programme that included introducing the teacher participants to the Internet, investigated whether the development of teacher ICT skills through the design of cyberhunts in a learning-as-design context, has the potential to promote the critical and developmental outcomes which form the basis of the South African National Curriculum Statement (NCS) and Draft White Paper on e-Education. The research was conducted within the post-positivist paradigm underpinned by a critical realist position and made use of qualitative and quantitative data1 gathering methods (mixed research) within an interpretative case study. Several different quantitative and qualitative data collection tools were used. Quantitative data gathering tools that had been used comprised of Likert scale questionnaires, a computer skills questionnaire, as well as certain sections within semi-closed-openended questionnaires. The qualitative data gathering tools that had been used were semi-closed-openended questionnaires, journal reflection sheets, observation and interviews. Ontologically the research was informed by a critical-realist perspective, epistemologically by a socio-cultural perspective; including situated learning within communities of practice; recognising the cognitive, social and situated learning dimension of teacher learning. Methodologically an interpretive case study approach was used, as the aim was to explore and investigate what the participants experienced, perceived and to understand the participants: what they felt, how they felt and why they felt and responded in certain ways. Initially the study focused on identifying how ready the participating schools and their participating teachers were in terms of the implementation and integration of Information and Communications Technology (ICT) with reference to first- and second order barriers. The findings suggest that addressing the first- and second order barriers is a vital aspect when assisting schools to move towards ICT integration. The next phase of the research focused on whether the cyberhunt design approach is capable of developing the critical outcomes of the NCS, whether it promotes motivation and interest, and whether it promotes collaboration. Both the quantitative and qualitative data portrayed positive results regarding the perceptions of the participating teachers in the cyberhunt design approach related to the critical and 1PLEASE NOTE: All the data referred to as in the appendix and all appendices are attached to this thesis on a CD containing the portable document format (PDF) files. This can be found at the back. iv developmental outcomes with reference to search and research, reading attitude, decision making, planning skills - which include time management and goal setting, knowledge and skills related to composing questions on different cognitive levels, computer skills, reflection and design skills. Positive results were also found related to audience, confidence, mental effort, motivation, interest and collaboration. The probabilities (p values) and practical statistical significance in the form of Cohen's d, were highly significant. The teachers’ final cyberhunt products suggest that the majority of the participants had obtained basic cyberhunt design skills. However, in spite of the positive results, it was found that not all teachers are yet ready to implement this approach exactly as it is intended. When interpreted within an activity theory perspective; the positive results might be attributed to the unmediated functioning of the rules, division of labour and community aspects of the theory, while the conditions required by complexity theory for the development of a complex learning community appear to have been met by the implementation of cyberhunts as a strategy. The conditions for enabling the development of a complex learning community; namely internal diversity, redundancy, decentralised control, organised randomness and neighbour interaction; also appear to have interacted with the unmediated aspects of activity theory in developing consensual rules and through the negotiation of the division of labour located within the community. In a like manner, positive results related to search and research, decision making, questioning, computer skills, reflection, design skills and audience reported can most likely be attributed to the functioning of the mediational tools as described by activity theory such as the computer technology, the Internet, the software that had been used and language. The data thus suggest that the interaction between both the unmediated elements and higher order mediated elements of activity theory, have most likely been the defining factors which created high levels of motivation, interest, collaboration and a positive classroom culture through which the critical and developmental outcomes of the South Africa curriculum can possibly be achieved within a complex learning community. The study also investigated how the teacher development process regarding ICT implementation should be managed. This study found that the acronym CRAR3FS2 holds the key to teacher development and classroom implementation. This acronym represents the verbs or actions that the participating teachers highly valued during implementation and what they have indicated as being important, namely: Care, Relate, Assess, Reflect, Read, Re-Plan, Feedback, Share and Support.
- Full Text:
- Date Issued: 2010
- Authors: Du Plessis, André
- Date: 2010
- Subjects: Educational technology , Computers -- Study and teaching , Computer-assisted instruction , Competency-based education
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9555 , http://hdl.handle.net/10948/1210 , Educational technology , Computers -- Study and teaching , Computer-assisted instruction , Competency-based education
- Description: This study, which is based on a computer literacy teacher development programme that included introducing the teacher participants to the Internet, investigated whether the development of teacher ICT skills through the design of cyberhunts in a learning-as-design context, has the potential to promote the critical and developmental outcomes which form the basis of the South African National Curriculum Statement (NCS) and Draft White Paper on e-Education. The research was conducted within the post-positivist paradigm underpinned by a critical realist position and made use of qualitative and quantitative data1 gathering methods (mixed research) within an interpretative case study. Several different quantitative and qualitative data collection tools were used. Quantitative data gathering tools that had been used comprised of Likert scale questionnaires, a computer skills questionnaire, as well as certain sections within semi-closed-openended questionnaires. The qualitative data gathering tools that had been used were semi-closed-openended questionnaires, journal reflection sheets, observation and interviews. Ontologically the research was informed by a critical-realist perspective, epistemologically by a socio-cultural perspective; including situated learning within communities of practice; recognising the cognitive, social and situated learning dimension of teacher learning. Methodologically an interpretive case study approach was used, as the aim was to explore and investigate what the participants experienced, perceived and to understand the participants: what they felt, how they felt and why they felt and responded in certain ways. Initially the study focused on identifying how ready the participating schools and their participating teachers were in terms of the implementation and integration of Information and Communications Technology (ICT) with reference to first- and second order barriers. The findings suggest that addressing the first- and second order barriers is a vital aspect when assisting schools to move towards ICT integration. The next phase of the research focused on whether the cyberhunt design approach is capable of developing the critical outcomes of the NCS, whether it promotes motivation and interest, and whether it promotes collaboration. Both the quantitative and qualitative data portrayed positive results regarding the perceptions of the participating teachers in the cyberhunt design approach related to the critical and 1PLEASE NOTE: All the data referred to as in the appendix and all appendices are attached to this thesis on a CD containing the portable document format (PDF) files. This can be found at the back. iv developmental outcomes with reference to search and research, reading attitude, decision making, planning skills - which include time management and goal setting, knowledge and skills related to composing questions on different cognitive levels, computer skills, reflection and design skills. Positive results were also found related to audience, confidence, mental effort, motivation, interest and collaboration. The probabilities (p values) and practical statistical significance in the form of Cohen's d, were highly significant. The teachers’ final cyberhunt products suggest that the majority of the participants had obtained basic cyberhunt design skills. However, in spite of the positive results, it was found that not all teachers are yet ready to implement this approach exactly as it is intended. When interpreted within an activity theory perspective; the positive results might be attributed to the unmediated functioning of the rules, division of labour and community aspects of the theory, while the conditions required by complexity theory for the development of a complex learning community appear to have been met by the implementation of cyberhunts as a strategy. The conditions for enabling the development of a complex learning community; namely internal diversity, redundancy, decentralised control, organised randomness and neighbour interaction; also appear to have interacted with the unmediated aspects of activity theory in developing consensual rules and through the negotiation of the division of labour located within the community. In a like manner, positive results related to search and research, decision making, questioning, computer skills, reflection, design skills and audience reported can most likely be attributed to the functioning of the mediational tools as described by activity theory such as the computer technology, the Internet, the software that had been used and language. The data thus suggest that the interaction between both the unmediated elements and higher order mediated elements of activity theory, have most likely been the defining factors which created high levels of motivation, interest, collaboration and a positive classroom culture through which the critical and developmental outcomes of the South Africa curriculum can possibly be achieved within a complex learning community. The study also investigated how the teacher development process regarding ICT implementation should be managed. This study found that the acronym CRAR3FS2 holds the key to teacher development and classroom implementation. This acronym represents the verbs or actions that the participating teachers highly valued during implementation and what they have indicated as being important, namely: Care, Relate, Assess, Reflect, Read, Re-Plan, Feedback, Share and Support.
- Full Text:
- Date Issued: 2010
The phytogeography of the Sneeuberg, Nuweveldberge and Roggeveldberge (Great Escarpment): assessing migration routes and endemism
- Authors: Clark, Vincent Ralph
- Date: 2010
- Subjects: Phytogeography -- South Africa Endemic plants -- South Africa Plants -- Migration -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4187 , http://hdl.handle.net/10962/d1003756
- Description: The Great Escarpment forms a semi-continuous mountain system 5 000 km long, stretching from Angola in the north-west, south through Namibia, and into western, southern and eastern South Africa, including Lesotho and Swaziland. It is composed of a wide variety of geological suites but is unified in representing the edge of the African plateau and the passive Gondwanan continental margin. The Great Escarpment falls into all major climatic zones on the subcontinent, is a repository of palaeo- and neo-endemics, hosts more than half of southern Africa‟s centres of plant endemism, and has a rich suite of endemic fauna. In addition, the Great Escarpment is believed to be both a refugium and corridor for biological diversity. Despite the biological richness of the Great Escarpment, research to date has been fragmented and many sections of the Great Escarpment have not been studied. The aim of this study is to contribute to research on the Great Escarpment by undertaking a detailed floristic study of the southern Great Escarpment (the Sneeuberg, Nuweveldberge and Roggeveldberge). Together these mountains comprise approximately 1 000 km (one fifth) of the Great Escarpment, and occupy a transition zone between the summer rainfall zone in the east and the winter rainfall zone in the west. They are also the sections of Great Escarpment most closely situated to the Cape Floristic Region (CFR) and would thus be involved in hypothesised migration routes for lineages that also occur further north through the Drakensberg Alpine Centre (DAC) to the East African mountain chain. Detailed fieldwork of the southern Great Escarpment was undertaken over a period of four years in all seasons. Approximately 8 000 specimens were collected. Particular emphasis was placed on areas that may represent refugia, i.e. the highest plateaux and peaks, mesic areas and cliff-lines. An overview of each mountain range, together with their endemic plant species and phytogeography, is provided. Approximately ten new species have been discovered during this study, two of which have been described to date. Numerous endemics only known from their types have also been rediscovered. The Sneeuberg is defined as a new centre of plant endemism on the Great Escarpment (endemism of 2.3%), and the role of the Boschberg and Groot-Bruintjieshoogde (part of the Sneeuberg) as a nexus for floristic migration routes is discussed. The Nuweveldberge is shown to have low endemism despite a floristic tally similar to the Sneeuberg, while the Roggeveldberge are confirmed to be the most endemic-rich section of the southern Great Escarpment. The field data collected was augmented by available data in taxonomic revisions, and floras for the Sneeuberg, Nuweveldberge and Roggeveldberge were compiled. In order to floristically compare the southern Great Escarpment with other sections of the Great Escarpment and the CFR, a database of some 12 000 taxa was created using available floristic data for the CFR, DAC and Great WinterbergAmatolas, together with the data collated for the Sneeuberg, Nuweveldberge and Roggeveldberge. These data were analysed using phenetic methods and Parsimony Analysis of Endemicity (PAE). The results indicate stronger linkages in the east, particularly between the Sneeuberg and Nuweveldberge, and between the Sneeuberg and the Great WinterbergAmatolas. The relationship of the Roggeveldberge with the rest of the southern Great Escarpment remains ambiguous. In order to refine notions of connectivity and migration routes, 19 well-sampled phylogenies were assessed for sister-taxon disjunctions to explore CFRGreat Escarpment connections. Palaeo-connectivity between the CFR and southern Great Escarpment is most strongly supported for the south-eastern (SE) connection, and less so for the north-western (NW) and Matjiesfontein connections. There is support for the current (or recent) use of these three connections from numerous species that occur on both sides of the connections. Results of these analyses indicate that the southern Great Escarpment is a palaeo-corridor, the functioning of which has been broken by the aridification of the Nuweveldberge since the Last Glacial Maximum (LGM). Floristic connectivity is strongest in the east, from the Nuweveldberge to the DAC, and is less so in the west between the Nuweveldberge and the Roggeveldberge a finding attributed to the transition from a reliable winter rainfall regime on the Roggeveldberge to an unpredictable moisture regime on the Nuweveldberge. The mountains of the southern Great Escarpment are thus a series of refugia from a previous moister, cooler climate and are a corridor between the eastern and western components of the Great Escarpment. The SE connection is the primary link between the CFR and the eastern Great Escarpment Afromontane region in southern Africa. The implications of this research are that accurate conservation assessments and Red Data listings for many of the previously poorly-known endemics can now be made, and appropriate conservation measures implemented. Climate change remains the primary threat to these endemics and montane taxa in general, while degradation of wetlands is the primary threat to the water catchment service provided by the southern Great Escarpment. Future detailed research on the Great WinterbergAmatolas and Stormberg and a comprehensive flora of the HantamRoggeveldberge will further enhance our understanding of the floristics of the southern Great Escarpment, and provide the necessary data for comprehensive GIS-based models of proposed climate change scenarios for local, regional and national conservation planning.
- Full Text:
- Date Issued: 2010
- Authors: Clark, Vincent Ralph
- Date: 2010
- Subjects: Phytogeography -- South Africa Endemic plants -- South Africa Plants -- Migration -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4187 , http://hdl.handle.net/10962/d1003756
- Description: The Great Escarpment forms a semi-continuous mountain system 5 000 km long, stretching from Angola in the north-west, south through Namibia, and into western, southern and eastern South Africa, including Lesotho and Swaziland. It is composed of a wide variety of geological suites but is unified in representing the edge of the African plateau and the passive Gondwanan continental margin. The Great Escarpment falls into all major climatic zones on the subcontinent, is a repository of palaeo- and neo-endemics, hosts more than half of southern Africa‟s centres of plant endemism, and has a rich suite of endemic fauna. In addition, the Great Escarpment is believed to be both a refugium and corridor for biological diversity. Despite the biological richness of the Great Escarpment, research to date has been fragmented and many sections of the Great Escarpment have not been studied. The aim of this study is to contribute to research on the Great Escarpment by undertaking a detailed floristic study of the southern Great Escarpment (the Sneeuberg, Nuweveldberge and Roggeveldberge). Together these mountains comprise approximately 1 000 km (one fifth) of the Great Escarpment, and occupy a transition zone between the summer rainfall zone in the east and the winter rainfall zone in the west. They are also the sections of Great Escarpment most closely situated to the Cape Floristic Region (CFR) and would thus be involved in hypothesised migration routes for lineages that also occur further north through the Drakensberg Alpine Centre (DAC) to the East African mountain chain. Detailed fieldwork of the southern Great Escarpment was undertaken over a period of four years in all seasons. Approximately 8 000 specimens were collected. Particular emphasis was placed on areas that may represent refugia, i.e. the highest plateaux and peaks, mesic areas and cliff-lines. An overview of each mountain range, together with their endemic plant species and phytogeography, is provided. Approximately ten new species have been discovered during this study, two of which have been described to date. Numerous endemics only known from their types have also been rediscovered. The Sneeuberg is defined as a new centre of plant endemism on the Great Escarpment (endemism of 2.3%), and the role of the Boschberg and Groot-Bruintjieshoogde (part of the Sneeuberg) as a nexus for floristic migration routes is discussed. The Nuweveldberge is shown to have low endemism despite a floristic tally similar to the Sneeuberg, while the Roggeveldberge are confirmed to be the most endemic-rich section of the southern Great Escarpment. The field data collected was augmented by available data in taxonomic revisions, and floras for the Sneeuberg, Nuweveldberge and Roggeveldberge were compiled. In order to floristically compare the southern Great Escarpment with other sections of the Great Escarpment and the CFR, a database of some 12 000 taxa was created using available floristic data for the CFR, DAC and Great WinterbergAmatolas, together with the data collated for the Sneeuberg, Nuweveldberge and Roggeveldberge. These data were analysed using phenetic methods and Parsimony Analysis of Endemicity (PAE). The results indicate stronger linkages in the east, particularly between the Sneeuberg and Nuweveldberge, and between the Sneeuberg and the Great WinterbergAmatolas. The relationship of the Roggeveldberge with the rest of the southern Great Escarpment remains ambiguous. In order to refine notions of connectivity and migration routes, 19 well-sampled phylogenies were assessed for sister-taxon disjunctions to explore CFRGreat Escarpment connections. Palaeo-connectivity between the CFR and southern Great Escarpment is most strongly supported for the south-eastern (SE) connection, and less so for the north-western (NW) and Matjiesfontein connections. There is support for the current (or recent) use of these three connections from numerous species that occur on both sides of the connections. Results of these analyses indicate that the southern Great Escarpment is a palaeo-corridor, the functioning of which has been broken by the aridification of the Nuweveldberge since the Last Glacial Maximum (LGM). Floristic connectivity is strongest in the east, from the Nuweveldberge to the DAC, and is less so in the west between the Nuweveldberge and the Roggeveldberge a finding attributed to the transition from a reliable winter rainfall regime on the Roggeveldberge to an unpredictable moisture regime on the Nuweveldberge. The mountains of the southern Great Escarpment are thus a series of refugia from a previous moister, cooler climate and are a corridor between the eastern and western components of the Great Escarpment. The SE connection is the primary link between the CFR and the eastern Great Escarpment Afromontane region in southern Africa. The implications of this research are that accurate conservation assessments and Red Data listings for many of the previously poorly-known endemics can now be made, and appropriate conservation measures implemented. Climate change remains the primary threat to these endemics and montane taxa in general, while degradation of wetlands is the primary threat to the water catchment service provided by the southern Great Escarpment. Future detailed research on the Great WinterbergAmatolas and Stormberg and a comprehensive flora of the HantamRoggeveldberge will further enhance our understanding of the floristics of the southern Great Escarpment, and provide the necessary data for comprehensive GIS-based models of proposed climate change scenarios for local, regional and national conservation planning.
- Full Text:
- Date Issued: 2010
The use of response surface methodology and artificial neural networks for the establishment of a design space for a sustained release salbutamol sulphate formulation
- Authors: Chaibva, Faith Anesu
- Date: 2010
- Subjects: Salbutamol sulphate Artificial intelligence -- Medical applications Neural networks (Computer science) Response surfaces (Statistics) Pharmaceutical biotechnology -- Quality contro Drugs -- Design Pharmacokinetics Drugs -- Dosage forms Drugs -- Controlled release
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3845 , http://hdl.handle.net/10962/d1010432
- Description: Quality by Design (QbD) is a systematic approach that has been recommended as suitable for the development of quality pharmaceutical products. The QbD approach commences with the definition of a quality target drug profile and predetermined objectives that are then used to direct the formulation development process with an emphasis on understanding the pharmaceutical science and manufacturing principles that apply to a product. The design space is directly linked to the use of QbD for formulation development and is a multidimensional combination and interaction of input variables and process parameters that have been demonstrated to provide an assurance of quality. The objective of these studies was to apply the principles of QbD as a framework for the optimisation of a sustained release (SR) formulation of salbutamol sulphate (SBS), and for the establishment of a design space using Response Surface Methodology (RSM) and Artificial Neural Networks (ANN). SBS is a short-acting ♭₂ agonist that is used for the management of asthma and chronic obstructive pulmonary disease (COPD). The use of a SR formulation of SBS may provide clinical benefits in the management of these respiratory disorders. Ashtalin®8 ER (Cipla Ltd., Mumbai, Maharashtra, India) was selected as a reference formulation for use in these studies. An Ishikawa or Cause and Effect diagram was used to determine the impact of formulation and process factors that have the potential to affect product quality. Key areas of concern that must be monitored include the raw materials, the manufacturing equipment and processes, and the analytical and assessment methods employed. The conditions in the laboratory and manufacturing processes were carefully monitored and recorded for any deviation from protocol, and equipment for assessment of dosage form performance, including dissolution equipment, balances and hardness testers, underwent regular maintenance. Preliminary studies to assess the potential utility of Methocel® Kl OOM, alone and in combination with other matrix forming polymers, revealed that the combination of this polymer with xanthan gum and Carbopol® has the potential to modulate the release of SBS at a specific rate, for a period of 12 hr. A central composite design using Methocel® KlOOM, xanthan gum, Carbopol® 974P and Surelease® as the granulating fluid was constructed to fully evaluate the impact of these formulation variables on the rate and extent of SBS release from manufactured formulations. The results revealed that although Methocel® KlOOM and xanthan gum had the greatest retardant effect on drug release, interactions between the polymers used in the study were also important determinants of the measureable responses. An ANN model was trained for optimisation using the data generated from a central composite study. The efficiency of the network was optimised by assessing the impact of the number of nodes in the hidden layer using a three layer Multi Layer Perceptron (MLP). The results revealed that a network with nine nodes in the hidden layer had the best predictive ability, suitable for application to formulation optimisation studies. Pharmaceutical optimisation was conducted using both the RSM and the trained ANN models. The results from the two optimisation procedures yielded two different formulation compositions that were subjected to in vitro dissolution testing using USP Apparatus 3. The results revealed that, although the formulation compositions that were derived from the optimisation procedures were different, both solutions gave reproducible results for which the dissolution profiles were indeed similar to that of the reference formulation. RSM and ANN were further investigated as possible means of establishing a design space for formulation compositions that would result in dosage forms that have similar in vitro release test profiles comparable to the reference product. Constraint plots were used to determine the bounds of the formulation variables that would result in the manufacture of dosage forms with the desired release profile. ANN simulations with hypothetical formulations that were generated within a small region of the experimental domain were investigated as a means of understanding the impact of varying the composition of the formulation on resultant dissolution profiles. Although both methods were suitable for the establishment of a design space, the use of ANN may be better suited for this purpose because of the manner in which ANN handles data. As more information about the behaviour of a formulation and its processes is generated during the product Iifecycle, ANN may be used to evaluate the impact of formulation and process variables on measureable responses. It is recommended that ANN may be suitable for the optimisation of pharmaceutical formulations and establishment of a design space in line with ICH Pharmaceutical Development [1], Quality Risk Management [2] and Pharmaceutical Quality Systems [3]
- Full Text:
- Date Issued: 2010
- Authors: Chaibva, Faith Anesu
- Date: 2010
- Subjects: Salbutamol sulphate Artificial intelligence -- Medical applications Neural networks (Computer science) Response surfaces (Statistics) Pharmaceutical biotechnology -- Quality contro Drugs -- Design Pharmacokinetics Drugs -- Dosage forms Drugs -- Controlled release
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3845 , http://hdl.handle.net/10962/d1010432
- Description: Quality by Design (QbD) is a systematic approach that has been recommended as suitable for the development of quality pharmaceutical products. The QbD approach commences with the definition of a quality target drug profile and predetermined objectives that are then used to direct the formulation development process with an emphasis on understanding the pharmaceutical science and manufacturing principles that apply to a product. The design space is directly linked to the use of QbD for formulation development and is a multidimensional combination and interaction of input variables and process parameters that have been demonstrated to provide an assurance of quality. The objective of these studies was to apply the principles of QbD as a framework for the optimisation of a sustained release (SR) formulation of salbutamol sulphate (SBS), and for the establishment of a design space using Response Surface Methodology (RSM) and Artificial Neural Networks (ANN). SBS is a short-acting ♭₂ agonist that is used for the management of asthma and chronic obstructive pulmonary disease (COPD). The use of a SR formulation of SBS may provide clinical benefits in the management of these respiratory disorders. Ashtalin®8 ER (Cipla Ltd., Mumbai, Maharashtra, India) was selected as a reference formulation for use in these studies. An Ishikawa or Cause and Effect diagram was used to determine the impact of formulation and process factors that have the potential to affect product quality. Key areas of concern that must be monitored include the raw materials, the manufacturing equipment and processes, and the analytical and assessment methods employed. The conditions in the laboratory and manufacturing processes were carefully monitored and recorded for any deviation from protocol, and equipment for assessment of dosage form performance, including dissolution equipment, balances and hardness testers, underwent regular maintenance. Preliminary studies to assess the potential utility of Methocel® Kl OOM, alone and in combination with other matrix forming polymers, revealed that the combination of this polymer with xanthan gum and Carbopol® has the potential to modulate the release of SBS at a specific rate, for a period of 12 hr. A central composite design using Methocel® KlOOM, xanthan gum, Carbopol® 974P and Surelease® as the granulating fluid was constructed to fully evaluate the impact of these formulation variables on the rate and extent of SBS release from manufactured formulations. The results revealed that although Methocel® KlOOM and xanthan gum had the greatest retardant effect on drug release, interactions between the polymers used in the study were also important determinants of the measureable responses. An ANN model was trained for optimisation using the data generated from a central composite study. The efficiency of the network was optimised by assessing the impact of the number of nodes in the hidden layer using a three layer Multi Layer Perceptron (MLP). The results revealed that a network with nine nodes in the hidden layer had the best predictive ability, suitable for application to formulation optimisation studies. Pharmaceutical optimisation was conducted using both the RSM and the trained ANN models. The results from the two optimisation procedures yielded two different formulation compositions that were subjected to in vitro dissolution testing using USP Apparatus 3. The results revealed that, although the formulation compositions that were derived from the optimisation procedures were different, both solutions gave reproducible results for which the dissolution profiles were indeed similar to that of the reference formulation. RSM and ANN were further investigated as possible means of establishing a design space for formulation compositions that would result in dosage forms that have similar in vitro release test profiles comparable to the reference product. Constraint plots were used to determine the bounds of the formulation variables that would result in the manufacture of dosage forms with the desired release profile. ANN simulations with hypothetical formulations that were generated within a small region of the experimental domain were investigated as a means of understanding the impact of varying the composition of the formulation on resultant dissolution profiles. Although both methods were suitable for the establishment of a design space, the use of ANN may be better suited for this purpose because of the manner in which ANN handles data. As more information about the behaviour of a formulation and its processes is generated during the product Iifecycle, ANN may be used to evaluate the impact of formulation and process variables on measureable responses. It is recommended that ANN may be suitable for the optimisation of pharmaceutical formulations and establishment of a design space in line with ICH Pharmaceutical Development [1], Quality Risk Management [2] and Pharmaceutical Quality Systems [3]
- Full Text:
- Date Issued: 2010
Tillage and crop rotation impacts on soil, quality parameters and maize yield in Zanyokwe Irrigation Scheme, South Africa
- Authors: Njaimwe, Arnold Ngare
- Date: 2010
- Subjects: No-tillage , Soil mechanics , Soils -- Quality , Cover crops , Corn -- Irrigation
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11962 , http://hdl.handle.net/10353/460 , No-tillage , Soil mechanics , Soils -- Quality , Cover crops , Corn -- Irrigation
- Description: Intensive tillage and monoculture cropping practices reduce soil C accumulation hence increasing soil vulnerability to chemical, physical and biological degradation. This study focussed on enhancing biomass production of wheat and oat winter cover crops as a means of increasing C sequestration in the low organic C soils of the central part of Eastern Cape Province. The specific objectives were (i) to evaluate the short-term effects of no till and cereal-fallow based crop rotations on; soil organic matter related parameters, pH and electrical conductivity, (ii) soil bulk density, water retention and aggregate stability, (iii) soil microbial biomass C and N, mineralizable N, soil respiration, and dehydrogenase enzyme activity, (iv) grain yield, soil nutrient concentration (N, P and K) and their uptake by maize, and (v) to identify soil parameters with high sensitivity to tillage under maize-fallow-maize, maize-wheat-maize and maize-oat-maize rotational cover cropping practices. The experiment was laid out as a split-plot arrangement in a randomized complete block design with 4 replicates. Tillage treatments (CT and NT) were applied on the main plots which measured 8 × 18 m while crop rotation treatments were applied in the subplots which measured 8 × 6 m. The rotation treatments were maize-fallow-maize (MFM), maize-wheat-maize (MWM) and maize-oat-maize (MOM). Weed control in NT plots involved preplant application of glyphosate to control mainly the grass weeds while post emergence weed management was done using Atrazine (485 atrazine and 15 g l-1 triazines). Initial weed control in CT plots was achieved through ploughing to a depth of 20 cm followed by disking while post emergence weed iii management was done by hand hoeing. Soil parameters measured were; (i) particulate organic matter (POM), soil organic carbon (SOC), total nitrogen (TN), pH and electrical conductivity (EC), (ii) soil bulk density (b), moisture at field capacity (FC), aggregate mean weight diameter (MWD) determined by fast wetting (FW), slow wetting (SW), mechanical breakdown by shaking (MB) and the stability index (SI), (iii) soil microbial biomass C (MBC) and N (MBN), mineralizable N (MN), soil respiration (SR), and dehydrogenase enzyme activity (DHEA). No-till increased POM and TN compared to CT in Lenye and Burnshill, respectively. The MWM and the MOM rotations increased TN relative to the MFM rotation in Lenye. The MWM and MOM rotations enhanced SOC relative to MFM in all sampled soil depths at Burnshill and similar observations were made under MOM rotation in the 5-20 cm depth in Lenye. The MWM and MOM rotations tended to depress soil pH relative to the MFM rotation in both sampled soil depths in Lenye while NT reduced soil pH relative to CT on the surface soil layer in Burnshill. Soil EC and pH varied with depth across tillage practices but both parameters remained within the ideal range for successful crop production over the study period. Soil stability index (SI) and aggregate MWD determined by FW, SW and MB were higher in Lenye compared to Burnshill. The MOM rotation enhanced the SI relative to MFM and MWM rotations at both sites. Scanning electron microscope (SEM) showed that more organic C was incorporated into the soil under NT and MOM rotation compared to CT and MFM rotation which had few organic coatings on the soil particles. Microbial properties varied with plant biomass input as influenced by tillage and type of rotational cover crop at both sites. Like in other past studies, NT showed higher levels of MBC, MBN, NM and SR at the soil surface layer compared to CT in Burnshill. No till increased MN iv relative to CT in both sampled soil depths in Lenye and resulted in higher DHEA compared to CT in Burnshill. The MOM rotation increased MBC, MBN, MN relative to MFM rotation especially within surface soil layer. Similar observations were made with respect to MN and SR in both sampled soil layers at Lenye. By contrast, the DHEA was higher under the MFM relative to the MWM and MOM rotations in Lenye but similar under the MFM and MOM rotations in Burnshill. Maize grain yield was not affected by both tillage and crop rotations but varied with cropping season. Comparable grain yields observed under the two tillage practices with similar fertilizer application rates indicated the advantage of NT over CT in saving on labour costs in maize production without compromising yields. High plant biomass retention under NT relative to CT contributed to high soil N and P levels under the former compared to the latter tillage practice especially on soil surface layer at both study sites. Principal component analysis (PCA) revealed that soil chemical and biological parameters closely linked to organic matter, namely SOC, MN, MBC and MBN showed the highest sensitivity to tillage and crop rotation treatments. Soil aggregate MWD determined by SW and b were the physical parameters which were highly altered by agronomic management practice. The MWM and MOM rotations were clustered together and clearly separated from the MFM rotation and this observed trend only applied to the 0-5 and 5-20 cm depths in Lenye site only. No till, MWM and MOM rotations enhanced POM, SOC and TN relative to CT and MFM rotation suggesting these practices have greater potential to improve soil chemical properties compared to intensive tillage and maize monoculture based production practices. Reduced soil b under MOM rotation and improved SI under NT compared to MFM and CT, respectively v indicate that these practices have the potential to improve degraded soils. Although not significantly different, NT values for MBC, MBN, MN, SR and DHEA were higher compared to CT indicating the potential of the practice to improve soil biotic activity relative to conventional tillage practices. No till enhanced surface soil nitrate N and extractable P compared to CT at both sites revealing the long-term potential of NT in improving the supply of these essential plant nutrients compared to CT. Principal component analysis showed that SOC, MN, K, P, MBC, MBN, soil aggregate MWD determined by SW and b were the most sensitive parameters to tillage and crop rotations. Therefore, these parameters could constitute the minimum data set for assessments of the impact of selected CA practices on soil quality attributes.
- Full Text:
- Date Issued: 2010
- Authors: Njaimwe, Arnold Ngare
- Date: 2010
- Subjects: No-tillage , Soil mechanics , Soils -- Quality , Cover crops , Corn -- Irrigation
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11962 , http://hdl.handle.net/10353/460 , No-tillage , Soil mechanics , Soils -- Quality , Cover crops , Corn -- Irrigation
- Description: Intensive tillage and monoculture cropping practices reduce soil C accumulation hence increasing soil vulnerability to chemical, physical and biological degradation. This study focussed on enhancing biomass production of wheat and oat winter cover crops as a means of increasing C sequestration in the low organic C soils of the central part of Eastern Cape Province. The specific objectives were (i) to evaluate the short-term effects of no till and cereal-fallow based crop rotations on; soil organic matter related parameters, pH and electrical conductivity, (ii) soil bulk density, water retention and aggregate stability, (iii) soil microbial biomass C and N, mineralizable N, soil respiration, and dehydrogenase enzyme activity, (iv) grain yield, soil nutrient concentration (N, P and K) and their uptake by maize, and (v) to identify soil parameters with high sensitivity to tillage under maize-fallow-maize, maize-wheat-maize and maize-oat-maize rotational cover cropping practices. The experiment was laid out as a split-plot arrangement in a randomized complete block design with 4 replicates. Tillage treatments (CT and NT) were applied on the main plots which measured 8 × 18 m while crop rotation treatments were applied in the subplots which measured 8 × 6 m. The rotation treatments were maize-fallow-maize (MFM), maize-wheat-maize (MWM) and maize-oat-maize (MOM). Weed control in NT plots involved preplant application of glyphosate to control mainly the grass weeds while post emergence weed management was done using Atrazine (485 atrazine and 15 g l-1 triazines). Initial weed control in CT plots was achieved through ploughing to a depth of 20 cm followed by disking while post emergence weed iii management was done by hand hoeing. Soil parameters measured were; (i) particulate organic matter (POM), soil organic carbon (SOC), total nitrogen (TN), pH and electrical conductivity (EC), (ii) soil bulk density (b), moisture at field capacity (FC), aggregate mean weight diameter (MWD) determined by fast wetting (FW), slow wetting (SW), mechanical breakdown by shaking (MB) and the stability index (SI), (iii) soil microbial biomass C (MBC) and N (MBN), mineralizable N (MN), soil respiration (SR), and dehydrogenase enzyme activity (DHEA). No-till increased POM and TN compared to CT in Lenye and Burnshill, respectively. The MWM and the MOM rotations increased TN relative to the MFM rotation in Lenye. The MWM and MOM rotations enhanced SOC relative to MFM in all sampled soil depths at Burnshill and similar observations were made under MOM rotation in the 5-20 cm depth in Lenye. The MWM and MOM rotations tended to depress soil pH relative to the MFM rotation in both sampled soil depths in Lenye while NT reduced soil pH relative to CT on the surface soil layer in Burnshill. Soil EC and pH varied with depth across tillage practices but both parameters remained within the ideal range for successful crop production over the study period. Soil stability index (SI) and aggregate MWD determined by FW, SW and MB were higher in Lenye compared to Burnshill. The MOM rotation enhanced the SI relative to MFM and MWM rotations at both sites. Scanning electron microscope (SEM) showed that more organic C was incorporated into the soil under NT and MOM rotation compared to CT and MFM rotation which had few organic coatings on the soil particles. Microbial properties varied with plant biomass input as influenced by tillage and type of rotational cover crop at both sites. Like in other past studies, NT showed higher levels of MBC, MBN, NM and SR at the soil surface layer compared to CT in Burnshill. No till increased MN iv relative to CT in both sampled soil depths in Lenye and resulted in higher DHEA compared to CT in Burnshill. The MOM rotation increased MBC, MBN, MN relative to MFM rotation especially within surface soil layer. Similar observations were made with respect to MN and SR in both sampled soil layers at Lenye. By contrast, the DHEA was higher under the MFM relative to the MWM and MOM rotations in Lenye but similar under the MFM and MOM rotations in Burnshill. Maize grain yield was not affected by both tillage and crop rotations but varied with cropping season. Comparable grain yields observed under the two tillage practices with similar fertilizer application rates indicated the advantage of NT over CT in saving on labour costs in maize production without compromising yields. High plant biomass retention under NT relative to CT contributed to high soil N and P levels under the former compared to the latter tillage practice especially on soil surface layer at both study sites. Principal component analysis (PCA) revealed that soil chemical and biological parameters closely linked to organic matter, namely SOC, MN, MBC and MBN showed the highest sensitivity to tillage and crop rotation treatments. Soil aggregate MWD determined by SW and b were the physical parameters which were highly altered by agronomic management practice. The MWM and MOM rotations were clustered together and clearly separated from the MFM rotation and this observed trend only applied to the 0-5 and 5-20 cm depths in Lenye site only. No till, MWM and MOM rotations enhanced POM, SOC and TN relative to CT and MFM rotation suggesting these practices have greater potential to improve soil chemical properties compared to intensive tillage and maize monoculture based production practices. Reduced soil b under MOM rotation and improved SI under NT compared to MFM and CT, respectively v indicate that these practices have the potential to improve degraded soils. Although not significantly different, NT values for MBC, MBN, MN, SR and DHEA were higher compared to CT indicating the potential of the practice to improve soil biotic activity relative to conventional tillage practices. No till enhanced surface soil nitrate N and extractable P compared to CT at both sites revealing the long-term potential of NT in improving the supply of these essential plant nutrients compared to CT. Principal component analysis showed that SOC, MN, K, P, MBC, MBN, soil aggregate MWD determined by SW and b were the most sensitive parameters to tillage and crop rotations. Therefore, these parameters could constitute the minimum data set for assessments of the impact of selected CA practices on soil quality attributes.
- Full Text:
- Date Issued: 2010