Attitudes, knowledge and behaviour of HIV positive pregnant women attending antenatal care in Buffalo city metropolitan district East London towards prevention of mother to child transmission (PMTCT)
- Matroshe, Florence Nozakhe Skoti
- Authors: Matroshe, Florence Nozakhe Skoti
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Nursing Science)
- Identifier: vital:11915 , http://hdl.handle.net/10353/d1016150
- Description: The National HIV and AIDS and STI strategic plan for South Africa, 2007-2011 aims to reduce the rate of mother to child transmission to less than 5% by 2011. On the World Aids day in 2009, the Honorable President Jacob Zuma announced the intervention to improve antiretroviral therapy (ARV), access to priority group’s in order to decrease the disease burden, to address maternal and child mortality, and to improve life expectancy (PMTCT Guidelines: 2010). According to the literature reviewed, accepting attitudes may indicate better knowledge and understanding of HIV and AIDS. Marking a change in South Africa’s history of HIV the South African Government launched a major HIV Counseling and Testing program campaign (HCT) in 2010. For the PMTCT program to work and be acceptable, it needs to be known by its clients. It helps the individual to know about their status so that they make important choices for self and others. Amongst the important choices, medications for opportunistic medications, ARV’S, behavior change, etc, are included (Project Literacy 2006:40). Aim and Objectives: The study assessed the knowledge that the pregnant women have towards the prevention of mother to-child transmission which includes HIV testing, antiretroviral prophylaxis during pregnancy, labour, and post natal and feeding options. Methods: A quantitative descriptive method was used for this study. The questionnaires developed by the researcher were used for data collection. The items on the questionnaire were divided into four (4) subsections. The questionnaire was administered to all positive pregnant women coming for follow up visit and those available at the time of data collection. Conclusion: In this study evaluation of the level of knowledge and attitude of positive pregnant women with regard to PMTCT in 5 Buffalo City Municipality clinics was conducted. It was found that some of positive pregnant women have better knowledge about PMTC though there were still those that need further education. Recommendations: The service providers, who are the professional nurses, should be provided with proper training on PMTCT program to improve their standard of service delivery and to capacitate them with knowledge and skills. Integration of HIV related health aspects during assessment and treatment of pregnant women should be strengthened, as the purpose of implementation of PMTCT was to reduce mortality rate by 50%, and also to reach the 4th Millennium Development Goal of reducing these deaths by two-thirds by 2015.east london towards prevention of mother to child transmission (pmtct)
- Full Text:
- Date Issued: 2014
- Authors: Matroshe, Florence Nozakhe Skoti
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Nursing Science)
- Identifier: vital:11915 , http://hdl.handle.net/10353/d1016150
- Description: The National HIV and AIDS and STI strategic plan for South Africa, 2007-2011 aims to reduce the rate of mother to child transmission to less than 5% by 2011. On the World Aids day in 2009, the Honorable President Jacob Zuma announced the intervention to improve antiretroviral therapy (ARV), access to priority group’s in order to decrease the disease burden, to address maternal and child mortality, and to improve life expectancy (PMTCT Guidelines: 2010). According to the literature reviewed, accepting attitudes may indicate better knowledge and understanding of HIV and AIDS. Marking a change in South Africa’s history of HIV the South African Government launched a major HIV Counseling and Testing program campaign (HCT) in 2010. For the PMTCT program to work and be acceptable, it needs to be known by its clients. It helps the individual to know about their status so that they make important choices for self and others. Amongst the important choices, medications for opportunistic medications, ARV’S, behavior change, etc, are included (Project Literacy 2006:40). Aim and Objectives: The study assessed the knowledge that the pregnant women have towards the prevention of mother to-child transmission which includes HIV testing, antiretroviral prophylaxis during pregnancy, labour, and post natal and feeding options. Methods: A quantitative descriptive method was used for this study. The questionnaires developed by the researcher were used for data collection. The items on the questionnaire were divided into four (4) subsections. The questionnaire was administered to all positive pregnant women coming for follow up visit and those available at the time of data collection. Conclusion: In this study evaluation of the level of knowledge and attitude of positive pregnant women with regard to PMTCT in 5 Buffalo City Municipality clinics was conducted. It was found that some of positive pregnant women have better knowledge about PMTC though there were still those that need further education. Recommendations: The service providers, who are the professional nurses, should be provided with proper training on PMTCT program to improve their standard of service delivery and to capacitate them with knowledge and skills. Integration of HIV related health aspects during assessment and treatment of pregnant women should be strengthened, as the purpose of implementation of PMTCT was to reduce mortality rate by 50%, and also to reach the 4th Millennium Development Goal of reducing these deaths by two-thirds by 2015.east london towards prevention of mother to child transmission (pmtct)
- Full Text:
- Date Issued: 2014
Barriers and incentives to potential adoption of biofuel crops by smallholder farmers in selected areas in the Chris Hani and O.R. Tambo district municipalities, South Africa
- Authors: Cheteni, Priviledge
- Date: 2014
- Subjects: Renewable energy sources -- South Africa -- Eastern Cape , Energy crops industry -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11225 , http://hdl.handle.net/10353/d1020182 , Renewable energy sources -- South Africa -- Eastern Cape , Energy crops industry -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape
- Description: Since the launch of the Biofuels Industrial Strategy in 2007 by the South African government, only a few smallholder farmers have adopted biofuels for production. The government hopes to stimulate economic development and alleviate poverty by targeting areas that were previously neglected for agriculture by the apartheid government. However, there still appears to be a lack of a clear and comprehensive policy framework for the development of a South African biofuel industry, because the proposed initiatives have not been implemented to date. There are also concerns among stakeholders that government policy is taking too long to formulate, compounding existing uncertainty in the industry. This study therefore aims to identify barriers and incentives that influence the potential adoption of biofuel crops in selected areas in the Eastern Cape Province, South Africa. The study utilised a semi-structured questionnaire to record responses from 129 smallholder farmers that were identified through a snowballing sampling technique. Descriptive statistical analysis and a Heckman two-step model were applied to analyse the data. Analysis was done using SPSS 21 and EViews 8. Results obtained showed that the variables: arable land, incentives offered, challenges faced, labour source and farm experience were statistical significant at 5 or 10 percent p value to awareness of farmers to biofuel crops. Adoption of biofuel crops was statistically related to gender, qualification, membership to association and household size. The study recommends that the Biofuels Industrial Strategy Policy be revisited in order to have a mechanism of including smallholder farmers that it aims to empower with employment and improvement in their livelihoods. The government can help smallholder farmers by addressing the challenges they face in improving their output. Furthermore, it recommends that a national study on barriers and incentives that influence the adoption of biofuel crops be carried out in order to identify other factors that may hinder the Biofuels Strategy Policy aims in empowering the disadvantaged farmers.
- Full Text:
- Date Issued: 2014
- Authors: Cheteni, Priviledge
- Date: 2014
- Subjects: Renewable energy sources -- South Africa -- Eastern Cape , Energy crops industry -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11225 , http://hdl.handle.net/10353/d1020182 , Renewable energy sources -- South Africa -- Eastern Cape , Energy crops industry -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape
- Description: Since the launch of the Biofuels Industrial Strategy in 2007 by the South African government, only a few smallholder farmers have adopted biofuels for production. The government hopes to stimulate economic development and alleviate poverty by targeting areas that were previously neglected for agriculture by the apartheid government. However, there still appears to be a lack of a clear and comprehensive policy framework for the development of a South African biofuel industry, because the proposed initiatives have not been implemented to date. There are also concerns among stakeholders that government policy is taking too long to formulate, compounding existing uncertainty in the industry. This study therefore aims to identify barriers and incentives that influence the potential adoption of biofuel crops in selected areas in the Eastern Cape Province, South Africa. The study utilised a semi-structured questionnaire to record responses from 129 smallholder farmers that were identified through a snowballing sampling technique. Descriptive statistical analysis and a Heckman two-step model were applied to analyse the data. Analysis was done using SPSS 21 and EViews 8. Results obtained showed that the variables: arable land, incentives offered, challenges faced, labour source and farm experience were statistical significant at 5 or 10 percent p value to awareness of farmers to biofuel crops. Adoption of biofuel crops was statistically related to gender, qualification, membership to association and household size. The study recommends that the Biofuels Industrial Strategy Policy be revisited in order to have a mechanism of including smallholder farmers that it aims to empower with employment and improvement in their livelihoods. The government can help smallholder farmers by addressing the challenges they face in improving their output. Furthermore, it recommends that a national study on barriers and incentives that influence the adoption of biofuel crops be carried out in order to identify other factors that may hinder the Biofuels Strategy Policy aims in empowering the disadvantaged farmers.
- Full Text:
- Date Issued: 2014
Basin analysis of the Soutpansberg and Tuli Coalfields, Limpopo Province of South Africa
- Authors: Malaza, Ntokozo
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: vital:11531 , http://hdl.handle.net/10353/d1021279
- Description: The Soutpansberg and Tuli Coalfields are both hosted in the Karoo Basin, Limpopo Province of South Africa. The Soutpansberg Coalfield is situated north of the Soutpansberg Mountain Range and has a strike length of about 200 km and width of about 80 km which is fault controlled and extends from Waterpoort in the west to the Kruger National Park in the east. The Tuli Coalfield occurs in a small intracratonic, east-west trending fault-controlled sedimentary basin with a preserved width of 80 km and length of 120 km. The east to west trend of the Tuli Coalfield parallels that of the Soutpansberg Coalfield further east, and the two coalfields link up with the north-south trending Lebombo Basin. The Tuli Coalfield occurs in the Tuli Basin, while the Soutpansberg Coalfield occurs in the Soutpansberg Basin. The two basins preserve a heterogeneous succession of the Upper Paleozoic to Lower Mesozoic sedimentary and volcanic rocks of the Karoo Supergroup. Because the area is largely covered by the Quaternary Kalahari Group sands, the stratigraphy of the succession is not as well understood as the Main Karoo Basin in South Africa. This study deals with the intra-basinal stratigraphic correlation, facies and depositional environments, petrography, geochemistry, provenance, geophysics, structural geology, diagenesis of sandstone, subsidence history and coal quality in the Soutpansberg and Tuli Coalfields. Based on the field work and detailed sedimentological analyses of over 2000 borehole data, seven facies associations (FAs) comprising sixteen major lithofacies were identified. The facies associations are: Glacial diamictite and sandstone (FA 1), Clast supported conglomerate and sandstone (FA 2), Tabular cross-bedded sandstone (FA 3), Trough and planar cross-bedded sandstone (FA 4), Fine calcareous and micaceous siltstone and mudstone (FA 5), Sandy shale/mudstone (FA 6), Laminated or thin-bedded Carbonaceous shale/mudstone and coal (FA 7). The facies associations (FA 1 to FA 7) correspond to the lithostratigraphic sub-divisions of the Tshidzi, Madzaringwe and Mikambeni Formations. The Madzaringwe Formation in this study is informally sub-divided into the Lower, Middle and Upper Members while the Mikambeni Formation is informally sub-divided into the Lower and Upper Members. Sedimentological characteristics of the identified facies associations indicate the following depositional environments: Fluvioglacial (braided streams) depositional environment (FA 1, Tshidzi Diamictite Formation); Floodplain ponds, lakes, marshes and backswamps (FA 6 and FA 7, Lower Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Middle Member of the Madzaringwe Formation); Floodplain ponds, lakes and backswamps (FA 6 and FA 7, Upper Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, swamps and shallow lakes (FA 5, FA 6 and FA 7, Lower Member of the Mikambeni Formation) and lastly braided channels, meandering channels, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Upper Member of the Mikambeni Formation). Paleocurrent directions were measured using directional structures (cross-bedding and asymmetric ripple marks). The paleocurrent analysis shows that the direction of the channels was from south-west to north-east in both coalfields. Based on the structural study and geophysical interpretations, the structural and tectonic settings of the two coalfields have been revealed, both coalfields are normal fault-bounded. The geological evolution of the Karoo strata, at least since the Upper Carboniferous, essentially follows the type model for passive continental margin terrain. Paleostress inversion techniques have been employed to interpret the stress regime of the two coalfields. The Soutpansberg Basin is characterised by W-E to ENE-WSW extension and N-S to NNW-SSE compression. The Tuli Basin is characterised by N-S to NNW-SSE compression and W-E to ENE-WSE extension. This stress field reflects the established structural trend of the two shear belts (the Tshipise and Siloam shear zones) bounding the Central Zone of the Limpopo Mobile Belt. The geophysical interpretations were focused on outlining structures, contacts and on the delineation of gravity, magnetic and radiometric signatures in areas defined as anomalous. The magnetic, gravity and radiometric data showed low amplitudes in the sedimentary strata compared to the surrounding and basement geological bodies. The E-N-E fault system has a notable signature, defining two magnetic domains on both southern and northern sides of the Soutpansberg Coalfield. The intrusive emplacements are mainly fault controlled and they trend in the same direction as the two fault systems. Jurassic volcanics (Letaba and Jozini Formations) follow a SW-NE trend, outcropping in the east (Soutpansberg Basin), producing a strong magnetic response in this area, and partly buried in the west, where magnetic intensity tends to be reduced. Petrographic and geochemical analyses of the Soutpansberg sandstones revealed immature sub-litharenite, sub-arkose and minor arkosic arenites in nature, dominated by sub-angular to rounded detrital grains, sourced from recycled orogens, craton interior to transitional continental. The sandstones of the Tuli Coalfield are classified as sub-arkoses and minor sub-litharenites and sourced from the craton interior and recycled orogen provenances. Both petrographic and geochemical results suggest a passive continental margin source. Petrographic and geochemical results of the samples of the Soutpansberg Coalfield suggest uplifted basement source areas dominated by sedimentary rocks with minor granite-gneiss rocks. The petrography and geochemistry of the Tuli sandstones suggest source areas dominantly composed of plutonic (granites) and metamorphic (gneisses and schists) rocks with a component from a sedimentary (quartz-arenites, quartzites, shales, arkoses and meta-arkoses) rocks. Diagenetic features of Mikambeni and Madzaringwe sandstones are subdivided into early, middle and late stages. Time is relative with the earliest diagenetic event occurring shortly after deposition and the latest occurring up until present time. The main diagenetic processes that have affected the sandstones include mechanical compaction, cementation and the dissolution of framework grains and cements. Early diagenetic processes include mechanical compaction, silica and calcite cementation, clay minerals (pore lining and pore-filling kaolinite, illite and smectite), feldspar authigenesis and the formation of hematite cements and coatings. Late diagenesis includes quartz and feldspar overgrowths, seritisation, chlorite alteration, grain deformation, pressure-solution and fracturing and albitisation. The subsidence of the basins is believed to be initiated and thermally controlled by tectonics (i.e. faults of basements blocks) rather than sedimentary burial. The subsidence within the basins supports the primary graben system which must have been centered within the present basins, and later became a region of major faulting. This gave way to the Late Carboniferous rapid subsidence, with areas of greater extension subsiding more rapidly. The Early Permian (last phase) is characterised by a slow subsidence representing the post-rift thermal subsidence. The rift flanks were gradually uplifted and, and then generally subsided as a results of thermal contraction after the extension terminated. Based on the coal analysis, both coalfields are characterised by coking bituminous coal. The study has revealed that the eastern Soutpansberg Coalfield is likely to present better opportunities for identification of potentially exploitable coal deposits as compared to the Tuli Coalfield.
- Full Text:
- Date Issued: 2014
- Authors: Malaza, Ntokozo
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Geology)
- Identifier: vital:11531 , http://hdl.handle.net/10353/d1021279
- Description: The Soutpansberg and Tuli Coalfields are both hosted in the Karoo Basin, Limpopo Province of South Africa. The Soutpansberg Coalfield is situated north of the Soutpansberg Mountain Range and has a strike length of about 200 km and width of about 80 km which is fault controlled and extends from Waterpoort in the west to the Kruger National Park in the east. The Tuli Coalfield occurs in a small intracratonic, east-west trending fault-controlled sedimentary basin with a preserved width of 80 km and length of 120 km. The east to west trend of the Tuli Coalfield parallels that of the Soutpansberg Coalfield further east, and the two coalfields link up with the north-south trending Lebombo Basin. The Tuli Coalfield occurs in the Tuli Basin, while the Soutpansberg Coalfield occurs in the Soutpansberg Basin. The two basins preserve a heterogeneous succession of the Upper Paleozoic to Lower Mesozoic sedimentary and volcanic rocks of the Karoo Supergroup. Because the area is largely covered by the Quaternary Kalahari Group sands, the stratigraphy of the succession is not as well understood as the Main Karoo Basin in South Africa. This study deals with the intra-basinal stratigraphic correlation, facies and depositional environments, petrography, geochemistry, provenance, geophysics, structural geology, diagenesis of sandstone, subsidence history and coal quality in the Soutpansberg and Tuli Coalfields. Based on the field work and detailed sedimentological analyses of over 2000 borehole data, seven facies associations (FAs) comprising sixteen major lithofacies were identified. The facies associations are: Glacial diamictite and sandstone (FA 1), Clast supported conglomerate and sandstone (FA 2), Tabular cross-bedded sandstone (FA 3), Trough and planar cross-bedded sandstone (FA 4), Fine calcareous and micaceous siltstone and mudstone (FA 5), Sandy shale/mudstone (FA 6), Laminated or thin-bedded Carbonaceous shale/mudstone and coal (FA 7). The facies associations (FA 1 to FA 7) correspond to the lithostratigraphic sub-divisions of the Tshidzi, Madzaringwe and Mikambeni Formations. The Madzaringwe Formation in this study is informally sub-divided into the Lower, Middle and Upper Members while the Mikambeni Formation is informally sub-divided into the Lower and Upper Members. Sedimentological characteristics of the identified facies associations indicate the following depositional environments: Fluvioglacial (braided streams) depositional environment (FA 1, Tshidzi Diamictite Formation); Floodplain ponds, lakes, marshes and backswamps (FA 6 and FA 7, Lower Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Middle Member of the Madzaringwe Formation); Floodplain ponds, lakes and backswamps (FA 6 and FA 7, Upper Member of the Madzaringwe Formation); Meandering and braided channels, crevasse splays, swamps and shallow lakes (FA 5, FA 6 and FA 7, Lower Member of the Mikambeni Formation) and lastly braided channels, meandering channels, levees and crevasse channels (FA 2, FA 3, FA 4 and FA 5, Upper Member of the Mikambeni Formation). Paleocurrent directions were measured using directional structures (cross-bedding and asymmetric ripple marks). The paleocurrent analysis shows that the direction of the channels was from south-west to north-east in both coalfields. Based on the structural study and geophysical interpretations, the structural and tectonic settings of the two coalfields have been revealed, both coalfields are normal fault-bounded. The geological evolution of the Karoo strata, at least since the Upper Carboniferous, essentially follows the type model for passive continental margin terrain. Paleostress inversion techniques have been employed to interpret the stress regime of the two coalfields. The Soutpansberg Basin is characterised by W-E to ENE-WSW extension and N-S to NNW-SSE compression. The Tuli Basin is characterised by N-S to NNW-SSE compression and W-E to ENE-WSE extension. This stress field reflects the established structural trend of the two shear belts (the Tshipise and Siloam shear zones) bounding the Central Zone of the Limpopo Mobile Belt. The geophysical interpretations were focused on outlining structures, contacts and on the delineation of gravity, magnetic and radiometric signatures in areas defined as anomalous. The magnetic, gravity and radiometric data showed low amplitudes in the sedimentary strata compared to the surrounding and basement geological bodies. The E-N-E fault system has a notable signature, defining two magnetic domains on both southern and northern sides of the Soutpansberg Coalfield. The intrusive emplacements are mainly fault controlled and they trend in the same direction as the two fault systems. Jurassic volcanics (Letaba and Jozini Formations) follow a SW-NE trend, outcropping in the east (Soutpansberg Basin), producing a strong magnetic response in this area, and partly buried in the west, where magnetic intensity tends to be reduced. Petrographic and geochemical analyses of the Soutpansberg sandstones revealed immature sub-litharenite, sub-arkose and minor arkosic arenites in nature, dominated by sub-angular to rounded detrital grains, sourced from recycled orogens, craton interior to transitional continental. The sandstones of the Tuli Coalfield are classified as sub-arkoses and minor sub-litharenites and sourced from the craton interior and recycled orogen provenances. Both petrographic and geochemical results suggest a passive continental margin source. Petrographic and geochemical results of the samples of the Soutpansberg Coalfield suggest uplifted basement source areas dominated by sedimentary rocks with minor granite-gneiss rocks. The petrography and geochemistry of the Tuli sandstones suggest source areas dominantly composed of plutonic (granites) and metamorphic (gneisses and schists) rocks with a component from a sedimentary (quartz-arenites, quartzites, shales, arkoses and meta-arkoses) rocks. Diagenetic features of Mikambeni and Madzaringwe sandstones are subdivided into early, middle and late stages. Time is relative with the earliest diagenetic event occurring shortly after deposition and the latest occurring up until present time. The main diagenetic processes that have affected the sandstones include mechanical compaction, cementation and the dissolution of framework grains and cements. Early diagenetic processes include mechanical compaction, silica and calcite cementation, clay minerals (pore lining and pore-filling kaolinite, illite and smectite), feldspar authigenesis and the formation of hematite cements and coatings. Late diagenesis includes quartz and feldspar overgrowths, seritisation, chlorite alteration, grain deformation, pressure-solution and fracturing and albitisation. The subsidence of the basins is believed to be initiated and thermally controlled by tectonics (i.e. faults of basements blocks) rather than sedimentary burial. The subsidence within the basins supports the primary graben system which must have been centered within the present basins, and later became a region of major faulting. This gave way to the Late Carboniferous rapid subsidence, with areas of greater extension subsiding more rapidly. The Early Permian (last phase) is characterised by a slow subsidence representing the post-rift thermal subsidence. The rift flanks were gradually uplifted and, and then generally subsided as a results of thermal contraction after the extension terminated. Based on the coal analysis, both coalfields are characterised by coking bituminous coal. The study has revealed that the eastern Soutpansberg Coalfield is likely to present better opportunities for identification of potentially exploitable coal deposits as compared to the Tuli Coalfield.
- Full Text:
- Date Issued: 2014
Biological evaluation and semi-synthesis of Isolated compounds from (Syzygium aromaticum (L.) Merr. & Perry) Buds
- Authors: Sibusiso, Rali
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11352 , http://hdl.handle.net/10353/d1021140
- Description: Natural products play a fundamental role in modern drug discovery as they continue providing diverse bioactive lead compounds for new drug formulation. However, isolation of these valued compounds is problematic. On the other hand, the morbidity and mortality rates caused by non-communicable diseases are increasing with improved longevity. Thus, the study herein focused on the isolation of plant-derived compounds from Syzygium aromaticum and evaluated their biological properties. Syzygium aromaticum is a well-known plant which belongs to family Myrtaceae. Dried flower buds of S. aromaticum were subjected to sequential solvent extraction. The ethyl acetate extract (15.535 g) was subjected to column chromatography using a silica gel (0.063-0.200 mm) for isolation. This has led to the isolation of three distinct compounds that were identified as eugenol, maslinic acid (MA) and oleanolic acid (OA). The structural elucidation of these valued compounds was done using NMR, GC-MS, LC-MS, FT-IR and Mp. Further semi-synthesis of the oleanolic acid afforded acetate and ester OA-derived compounds with better solubility properties. All these compounds were evaluated for analgesic and anti-inflammatory properties. All tested compounds were administered at a dose of 40 mg/kg to both Wistar rats and Swiss mice. Significant (p<0.01) analgesic and anti-inflammatory properties are obtained for all compounds. The effects of eugenol in all experiment were better except in the thermal-induced pain or tail flick test. In the case of modified compounds, the formalin induced pain test disclosed that oleanane derived compounds confessed analgesic and anti-inflammatory effects better than OA, whereas, in tale flick test oleanolic acid proved superior analgesic effects compared to all its derivatives with the exception of the acetyl-derivative. Acute anti-inflammatory test showed that acetyl-derivatives were more active than other compounds. In conclusion, chromatographic techniques and semi-synthesise of oleanolic acid have resulted to several plant-derived compounds with analgesic and anti-inflammatory properties. The semi-synthesized compounds may serve as alternative drug candidates for new analgesic and anti-inflammatory drug formulation
- Full Text:
- Date Issued: 2014
- Authors: Sibusiso, Rali
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: vital:11352 , http://hdl.handle.net/10353/d1021140
- Description: Natural products play a fundamental role in modern drug discovery as they continue providing diverse bioactive lead compounds for new drug formulation. However, isolation of these valued compounds is problematic. On the other hand, the morbidity and mortality rates caused by non-communicable diseases are increasing with improved longevity. Thus, the study herein focused on the isolation of plant-derived compounds from Syzygium aromaticum and evaluated their biological properties. Syzygium aromaticum is a well-known plant which belongs to family Myrtaceae. Dried flower buds of S. aromaticum were subjected to sequential solvent extraction. The ethyl acetate extract (15.535 g) was subjected to column chromatography using a silica gel (0.063-0.200 mm) for isolation. This has led to the isolation of three distinct compounds that were identified as eugenol, maslinic acid (MA) and oleanolic acid (OA). The structural elucidation of these valued compounds was done using NMR, GC-MS, LC-MS, FT-IR and Mp. Further semi-synthesis of the oleanolic acid afforded acetate and ester OA-derived compounds with better solubility properties. All these compounds were evaluated for analgesic and anti-inflammatory properties. All tested compounds were administered at a dose of 40 mg/kg to both Wistar rats and Swiss mice. Significant (p<0.01) analgesic and anti-inflammatory properties are obtained for all compounds. The effects of eugenol in all experiment were better except in the thermal-induced pain or tail flick test. In the case of modified compounds, the formalin induced pain test disclosed that oleanane derived compounds confessed analgesic and anti-inflammatory effects better than OA, whereas, in tale flick test oleanolic acid proved superior analgesic effects compared to all its derivatives with the exception of the acetyl-derivative. Acute anti-inflammatory test showed that acetyl-derivatives were more active than other compounds. In conclusion, chromatographic techniques and semi-synthesise of oleanolic acid have resulted to several plant-derived compounds with analgesic and anti-inflammatory properties. The semi-synthesized compounds may serve as alternative drug candidates for new analgesic and anti-inflammatory drug formulation
- Full Text:
- Date Issued: 2014
Characterization and computer simulation of corn stover/coal blends for co-gasification in a downdraft gasifier
- Authors: Mabizela, Polycarp Sbusiso
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11600 , http://hdl.handle.net/10353/d1020203
- Description: The need for sustainable alternative energy technology is becoming more urgent as the demand for clean energy environment increases. For centuries, electricity in South Africa has been derived mostly from coal with results growing in multifold annually due to concerns about the impact of fossil fuel utilization related to emission of greenhouse gasses. It is practically impossible at the moment to replace coal with biomass resources because of the low energy value of biomass. However, the conversion of coal has experienced some challenges especially during its gasification which includes, but are not limited to a high reaction temperature exceeding 900°C which most gasifiers cannot achieve, and if achieved in most cases, combustion of the resulting syngas usually occur, leading to low conversion efficiency and the risk of reaching extremely high temperatures that may result in pressure build up and explosion may also occur. Therefore, this study sought to investigate the possibility of co-gasifying corn stover with coal with the ultimate aim establishing the best mixing ratio that would result in optimum co-gasification efficiency after computer simulation. Proximate and ultimate analysis, including energy values of corn stover and coal as well as their blends were undertaken and results showed significant differences between the two feedstocks and narrow range composition betwee their blends in terms of properties and energy value. Corn stover showed a higher fraction of volatile matter and lower ash content than coal, whereas those of their blends vary considerably in terms of physical properties. Differences in chemical composition also showed higher fraction of hydrogen and oxygen, and less carbon than coal while those of their blends vary according to the ratio of corn stover to coal and vice versa in the blends. The thermal stability of corn stover and coal as well as their blends were also established and the maximum temperature reached for thermal degradation of their blends was 900°C as depicted by TGA analysis. The SEM results revealed no changes in morphology of the pure samples of corn stover and coal which was due to the fact that a pre-treatment of the samples were not undertaken, whereas the blends showed significant changes in morphology as a result of blending. However, luminous and non-luminous features were noticed in both SEM images of the blends with the 10% coal/90% corn stover blend having higher percentages of luminosity as a result of higher quantities of coal in the blend. The energy density of the samples were also measured and found to be 16.1 MJ/kg and 22.8 MJ/kg for corn stover and coal respectively. Those of their blends varied from 16.9 to approximately 23.5 MJ/kg. These results were used to conduct computer simulation of the co-gasification process in order to establish the best blend that would result in maximum co-gasification efficiency. The blend 90% corn stover/10% coal was found to be the most suitable blend for co-gasification resulting in an efficiency of approximately 58% because its conversion was efficiently achieved at a temperature that is intermediate to that of coal and biomass independently. The simulation results were, however, compared with experimental data found in the literature and results showed only slight variation between them.
- Full Text:
- Date Issued: 2014
- Authors: Mabizela, Polycarp Sbusiso
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: vital:11600 , http://hdl.handle.net/10353/d1020203
- Description: The need for sustainable alternative energy technology is becoming more urgent as the demand for clean energy environment increases. For centuries, electricity in South Africa has been derived mostly from coal with results growing in multifold annually due to concerns about the impact of fossil fuel utilization related to emission of greenhouse gasses. It is practically impossible at the moment to replace coal with biomass resources because of the low energy value of biomass. However, the conversion of coal has experienced some challenges especially during its gasification which includes, but are not limited to a high reaction temperature exceeding 900°C which most gasifiers cannot achieve, and if achieved in most cases, combustion of the resulting syngas usually occur, leading to low conversion efficiency and the risk of reaching extremely high temperatures that may result in pressure build up and explosion may also occur. Therefore, this study sought to investigate the possibility of co-gasifying corn stover with coal with the ultimate aim establishing the best mixing ratio that would result in optimum co-gasification efficiency after computer simulation. Proximate and ultimate analysis, including energy values of corn stover and coal as well as their blends were undertaken and results showed significant differences between the two feedstocks and narrow range composition betwee their blends in terms of properties and energy value. Corn stover showed a higher fraction of volatile matter and lower ash content than coal, whereas those of their blends vary considerably in terms of physical properties. Differences in chemical composition also showed higher fraction of hydrogen and oxygen, and less carbon than coal while those of their blends vary according to the ratio of corn stover to coal and vice versa in the blends. The thermal stability of corn stover and coal as well as their blends were also established and the maximum temperature reached for thermal degradation of their blends was 900°C as depicted by TGA analysis. The SEM results revealed no changes in morphology of the pure samples of corn stover and coal which was due to the fact that a pre-treatment of the samples were not undertaken, whereas the blends showed significant changes in morphology as a result of blending. However, luminous and non-luminous features were noticed in both SEM images of the blends with the 10% coal/90% corn stover blend having higher percentages of luminosity as a result of higher quantities of coal in the blend. The energy density of the samples were also measured and found to be 16.1 MJ/kg and 22.8 MJ/kg for corn stover and coal respectively. Those of their blends varied from 16.9 to approximately 23.5 MJ/kg. These results were used to conduct computer simulation of the co-gasification process in order to establish the best blend that would result in maximum co-gasification efficiency. The blend 90% corn stover/10% coal was found to be the most suitable blend for co-gasification resulting in an efficiency of approximately 58% because its conversion was efficiently achieved at a temperature that is intermediate to that of coal and biomass independently. The simulation results were, however, compared with experimental data found in the literature and results showed only slight variation between them.
- Full Text:
- Date Issued: 2014
Clinical experiences of third-year student nurses in a public college in the Eastern Cape
- Authors: Tyanti, Mandisa
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Nursing Science)
- Identifier: vital:11912 , http://hdl.handle.net/10353/d1016097
- Description: Clinical experience has always been an important part of nursing education. Nursing colleges require students to be placed in clinical areas in order to acquire new knowledge and skills. The purpose of the study was to explore and describe the clinical experiences during their clinical placement of the third-year student nurses at a public college in the Eastern Cape. The objectives of this study were: to explore and describe the experiences of the third-year student of a public nursing college in the Eastern Cape, and to describe strategies for the improvement of student learning during clinical practice. A qualitative, explorative and descriptive research design was used to describe the clinical experiences of these student nurses and the strategies for the improvement of student learning during clinical practice. Data were collected from focus group interviews, using a purposive and convenience sample from one college campus in the Eastern Cape. Tesch’s method of data analysis (in Creswell, 2003) was used to analyse data. Trustworthiness was ensured in this research by using Guba’s model (in Lincoln & Guba, 1985) of qualitative research. Ethical approval was obtained from the University of Fort Hare Research Ethics Committee, the Department of Health, Eastern Cape, the Head of the Nursing College, the Campus Head and the participants and ethical consideration was ensured throughout the research process. Themes and sub-themes emerged from data collected about the clinical experiences of the nurses. The study brought to light the experiences of third-year student nurses during allocation to clinical areas. The findings from this study revealed the need for proper clinical accompaniment by college staff to ensure that clinical learning is taking place. Strategies to improve learning in the clinical areas are described. and recommendations for nursing education and nursing practice are made. If this is applied, it will help the student nurses to be better professionals.
- Full Text:
- Date Issued: 2014
- Authors: Tyanti, Mandisa
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Nursing Science)
- Identifier: vital:11912 , http://hdl.handle.net/10353/d1016097
- Description: Clinical experience has always been an important part of nursing education. Nursing colleges require students to be placed in clinical areas in order to acquire new knowledge and skills. The purpose of the study was to explore and describe the clinical experiences during their clinical placement of the third-year student nurses at a public college in the Eastern Cape. The objectives of this study were: to explore and describe the experiences of the third-year student of a public nursing college in the Eastern Cape, and to describe strategies for the improvement of student learning during clinical practice. A qualitative, explorative and descriptive research design was used to describe the clinical experiences of these student nurses and the strategies for the improvement of student learning during clinical practice. Data were collected from focus group interviews, using a purposive and convenience sample from one college campus in the Eastern Cape. Tesch’s method of data analysis (in Creswell, 2003) was used to analyse data. Trustworthiness was ensured in this research by using Guba’s model (in Lincoln & Guba, 1985) of qualitative research. Ethical approval was obtained from the University of Fort Hare Research Ethics Committee, the Department of Health, Eastern Cape, the Head of the Nursing College, the Campus Head and the participants and ethical consideration was ensured throughout the research process. Themes and sub-themes emerged from data collected about the clinical experiences of the nurses. The study brought to light the experiences of third-year student nurses during allocation to clinical areas. The findings from this study revealed the need for proper clinical accompaniment by college staff to ensure that clinical learning is taking place. Strategies to improve learning in the clinical areas are described. and recommendations for nursing education and nursing practice are made. If this is applied, it will help the student nurses to be better professionals.
- Full Text:
- Date Issued: 2014
Computational studies, synthesis and characterization of ruthenium (ii) anticancer complexes
- Authors: Adeniyi, Adebayo Azeez
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11338 , http://hdl.handle.net/10353/d1015577
- Description: This thesis is centred on the application of Ru-based complexes as a promising alternative to cis-platin in cancer chemotherapy. Cis-platin is known to be the most prescribed chemotherapy which has more than 70% application in cancer cases especially the testicular cancer. An insight is provided in Chapter One and Two into the literatures reports on the application of Ru(II)-based complexes in cancer chemotherapy. In order to address some of the pressing challenges in rational design of Ru-based anticancer complexes, section 3.3 and 3.4 deal with efforts to elucidate the complication of their chemistry and instability while in section 3.5 efforts are made to find solution to the lack of proper knowledge of their targets using different theoretical approaches as presented in Chapter Three. In addition to the theoretical study, this thesis also comprises of the synthesis of the bis-pyrazole derivatives type of ligands and the derivatives of their Ru(II)-based complexes as provided in Chapter Four and Five respectively. Also the computational methods were used to elucidate the structural and spectroscopic properties of the synthesised ligands and their Ru(II)-based complexes. The geometrical and electronic properties are studied in relation to the stability and the reported anticancer activities of Ru(II)-based complexes in section 3.3. In subsection 3.3.1, several quantum properties including the natural energy decomposition analysis (NEDA) and quantum theory of atoms in a molecule (QTAIM) are computed on three models of RAPTA-C complexes using DFT with hybrid functional and basis set with ECP and without ECP. The higher stability of Carbo-RAPTA-C and Oxalo-RAPTA-C over RAPTA-C comes from the lower exchange repulsion and higher polarization contributions to their stability which gives insight into experimental observation. A similar study was carried out in subsection 3.3.2 on half-sandwich Ru(II)-based anticancer complexes with 6-toluene and 6-trifluorotoluene.
- Full Text:
- Date Issued: 2014
- Authors: Adeniyi, Adebayo Azeez
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11338 , http://hdl.handle.net/10353/d1015577
- Description: This thesis is centred on the application of Ru-based complexes as a promising alternative to cis-platin in cancer chemotherapy. Cis-platin is known to be the most prescribed chemotherapy which has more than 70% application in cancer cases especially the testicular cancer. An insight is provided in Chapter One and Two into the literatures reports on the application of Ru(II)-based complexes in cancer chemotherapy. In order to address some of the pressing challenges in rational design of Ru-based anticancer complexes, section 3.3 and 3.4 deal with efforts to elucidate the complication of their chemistry and instability while in section 3.5 efforts are made to find solution to the lack of proper knowledge of their targets using different theoretical approaches as presented in Chapter Three. In addition to the theoretical study, this thesis also comprises of the synthesis of the bis-pyrazole derivatives type of ligands and the derivatives of their Ru(II)-based complexes as provided in Chapter Four and Five respectively. Also the computational methods were used to elucidate the structural and spectroscopic properties of the synthesised ligands and their Ru(II)-based complexes. The geometrical and electronic properties are studied in relation to the stability and the reported anticancer activities of Ru(II)-based complexes in section 3.3. In subsection 3.3.1, several quantum properties including the natural energy decomposition analysis (NEDA) and quantum theory of atoms in a molecule (QTAIM) are computed on three models of RAPTA-C complexes using DFT with hybrid functional and basis set with ECP and without ECP. The higher stability of Carbo-RAPTA-C and Oxalo-RAPTA-C over RAPTA-C comes from the lower exchange repulsion and higher polarization contributions to their stability which gives insight into experimental observation. A similar study was carried out in subsection 3.3.2 on half-sandwich Ru(II)-based anticancer complexes with 6-toluene and 6-trifluorotoluene.
- Full Text:
- Date Issued: 2014
Determinants of rural households’ diversification of livelihood strategies: a case of Intsika Yethu farmers of the Eastern Cape province, South Africa
- Authors: Munhenga, Daniel
- Date: 2014
- Subjects: Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11220 , http://hdl.handle.net/10353/d1019818 , Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Description: Despite the continuing perceived economic centrality of agriculture in Intsika Yethu local municipality, rural households engage and pursue diverse non-farm livelihood activities to cope with diverse challenges and risks such as drought. This study assessed the importance of existing livelihood strategies adopted by the different rural households in Intsika Yethu; the link between households’ ownership and access to different ‘assets’; factors determining households’ ability to adopt certain livelihood strategies in the area. A survey of 120 households in six administrative areas and informal discussions with key informants were used to collect demographic data, data on socio-economic activities and factors determining the choice of livelihood strategies of the households in Intsika Yethu. The research findings indicated that only about 10% of the interviewed households relied solely on on-farm livelihood strategy only. Credit, remittances, market distance, affiliating to cooperatives, education and household size have a potential of influencing households to shift from on-farm livelihood strategy to other livelihood strategies. The government may need to promote programs and awareness on how households can diversify their livelihood strategies as a way of coping with economic constraints in the area.
- Full Text:
- Date Issued: 2014
- Authors: Munhenga, Daniel
- Date: 2014
- Subjects: Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11220 , http://hdl.handle.net/10353/d1019818 , Sustainable development -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape , Farm management -- South Africa -- Eastern Cape
- Description: Despite the continuing perceived economic centrality of agriculture in Intsika Yethu local municipality, rural households engage and pursue diverse non-farm livelihood activities to cope with diverse challenges and risks such as drought. This study assessed the importance of existing livelihood strategies adopted by the different rural households in Intsika Yethu; the link between households’ ownership and access to different ‘assets’; factors determining households’ ability to adopt certain livelihood strategies in the area. A survey of 120 households in six administrative areas and informal discussions with key informants were used to collect demographic data, data on socio-economic activities and factors determining the choice of livelihood strategies of the households in Intsika Yethu. The research findings indicated that only about 10% of the interviewed households relied solely on on-farm livelihood strategy only. Credit, remittances, market distance, affiliating to cooperatives, education and household size have a potential of influencing households to shift from on-farm livelihood strategy to other livelihood strategies. The government may need to promote programs and awareness on how households can diversify their livelihood strategies as a way of coping with economic constraints in the area.
- Full Text:
- Date Issued: 2014
Development of a bench scale single batch biomass to liquid fuel facility
- Authors: Zhang, Yusheng
- Date: 2014
- Subjects: Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: http://hdl.handle.net/10353/811 , vital:26499 , Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Description: The research described in this dissertation was motivated by the global demand for energy that is not dependent on coal, oil, natural gas and other non-renewable fossil fuels. The technology used in this project is related to the use of biomass to produce a viable alternative to conventional sources of fuel. A bench scale biomass to liquid (BTL) facility was built and tested. This produced results confirming the feasibility of the BTL process. The findings of the pilot study outlined in this dissertation justified the conclusion that the next step will be to expand the capacity and productivity of the BTL pilot plant to an industrial scale. Biomass comes from a variety of renewable sources that are readily available. In this case, the material used in the fixed bed biomass gasification facility to generate wood gas was agricultural and forestry waste, such as straw and wood chips. The gasifier had the capacity to produce up to 10 cubic metres/hr of gas with a carbon monoxide and hydrogen content of between 20–40% by volume, when it was operated at ambient pressure and with air as the oxidizer. The gas, produced at a temperature above 700º C, was cooled in a quench/water scrubber in order to remove most of the mechanical impurities (tars and water-soluble inorganic particles), condensed and dried with corn cobs before being compressed in cylinders at over 100 bar (g) for use in the Fischer-Tropsch Synthesis (FTS). The syngas was subjected further to a series of refining processes which included removal of sulphur and oxygen. The sulphur removal technology chosen entailed applying modified activated carbon to adsorb H2S with the help of hydrolysis in order to convert organic sulphur impurities into H2S which reduced the sulphur content of the gas to less than 5 ppbv. Supported cobalt catalyst (100 grams), were loaded into a single-tube fixed bed FT reactor with an inner diameter of 50 mm. The reactor was fitted with a heating jacket through which, heated oil ran to cool the reactor during a normal reaction occurring at < 250 ºC, while nitrogen was used in the heating jacket during reduction, which occurred at temperatures up ~ 350 ºC. The FTS reaction was carried out at different pressures and temperatures. Liquid and wax products were produced from the facility. The properties of the liquid and solid hydrocarbons produced were found to be the same as FT products from other feed stocks, such as natural gas and coal.
- Full Text:
- Date Issued: 2014
- Authors: Zhang, Yusheng
- Date: 2014
- Subjects: Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Language: English
- Type: Thesis , Masters , MSc (Chemistry)
- Identifier: http://hdl.handle.net/10353/811 , vital:26499 , Biomass energy , Renewable energy sources , Energy conversion , Electric power production
- Description: The research described in this dissertation was motivated by the global demand for energy that is not dependent on coal, oil, natural gas and other non-renewable fossil fuels. The technology used in this project is related to the use of biomass to produce a viable alternative to conventional sources of fuel. A bench scale biomass to liquid (BTL) facility was built and tested. This produced results confirming the feasibility of the BTL process. The findings of the pilot study outlined in this dissertation justified the conclusion that the next step will be to expand the capacity and productivity of the BTL pilot plant to an industrial scale. Biomass comes from a variety of renewable sources that are readily available. In this case, the material used in the fixed bed biomass gasification facility to generate wood gas was agricultural and forestry waste, such as straw and wood chips. The gasifier had the capacity to produce up to 10 cubic metres/hr of gas with a carbon monoxide and hydrogen content of between 20–40% by volume, when it was operated at ambient pressure and with air as the oxidizer. The gas, produced at a temperature above 700º C, was cooled in a quench/water scrubber in order to remove most of the mechanical impurities (tars and water-soluble inorganic particles), condensed and dried with corn cobs before being compressed in cylinders at over 100 bar (g) for use in the Fischer-Tropsch Synthesis (FTS). The syngas was subjected further to a series of refining processes which included removal of sulphur and oxygen. The sulphur removal technology chosen entailed applying modified activated carbon to adsorb H2S with the help of hydrolysis in order to convert organic sulphur impurities into H2S which reduced the sulphur content of the gas to less than 5 ppbv. Supported cobalt catalyst (100 grams), were loaded into a single-tube fixed bed FT reactor with an inner diameter of 50 mm. The reactor was fitted with a heating jacket through which, heated oil ran to cool the reactor during a normal reaction occurring at < 250 ºC, while nitrogen was used in the heating jacket during reduction, which occurred at temperatures up ~ 350 ºC. The FTS reaction was carried out at different pressures and temperatures. Liquid and wax products were produced from the facility. The properties of the liquid and solid hydrocarbons produced were found to be the same as FT products from other feed stocks, such as natural gas and coal.
- Full Text:
- Date Issued: 2014
Development of an M-commerce security framework
- Murufu, Mufudzi Anesu Chapman
- Authors: Murufu, Mufudzi Anesu Chapman
- Date: 2014
- Subjects: Mobile commerce , Telecommunication systems
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/833 , vital:26501 , Mobile commerce , Telecommunication systems
- Description: Research shows how M-Commerce has managed to find its way to previously inaccessible parts of the world as a major Information and Communication Technologies (ICT) tool for development due to widespread introduction of mobile phones in remote areas. M-Commerce has offered valuable advantages: anytime, anywhere, more personal, more location-aware, more context-aware, more age aware, always online and instant connectivity. But this is not without its problems, of which security is high on the list. The security issues span the whole M-Commerce spectrum, from the top to the bottom layer of the OSI network protocol stack, from machines to humans. This research proposes a threat-mitigation modular framework to help address the security issues lurking in M-Commerce systems being used by marginalised rural community members. The research commences with a literature survey carried out to establish security aspects related to M-Commerce and to determine requirements for a security framework. The framework classifies M-Commerce security threat-vulnerability-risks into four levels: human behaviour and mobile device interaction security, mobile device security, M-Commerce access channel security, wireless network access security. This is followed by a review of the supporting structures or related frameworks that the proposed framework could leverage to address security issues on M-Commerce systems as ICT4D initiatives. The proposed security framework based on the requirements discovered is then presented. As a proof-of-concept, a case study was undertaken at the Siyakhula Living Lab at Dwesa in the Eastern Cape province of South Africa in order to validate the components of the proposed framework. Following the application of the framework in a case study, it can be argued that the proposed security framework allows for secure transacting by marginalised users using M-Commerce initiatives. The security framework is therefore useful in addressing the identified security requirements of M-Commerce in ICT4D contexts.
- Full Text:
- Date Issued: 2014
- Authors: Murufu, Mufudzi Anesu Chapman
- Date: 2014
- Subjects: Mobile commerce , Telecommunication systems
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/833 , vital:26501 , Mobile commerce , Telecommunication systems
- Description: Research shows how M-Commerce has managed to find its way to previously inaccessible parts of the world as a major Information and Communication Technologies (ICT) tool for development due to widespread introduction of mobile phones in remote areas. M-Commerce has offered valuable advantages: anytime, anywhere, more personal, more location-aware, more context-aware, more age aware, always online and instant connectivity. But this is not without its problems, of which security is high on the list. The security issues span the whole M-Commerce spectrum, from the top to the bottom layer of the OSI network protocol stack, from machines to humans. This research proposes a threat-mitigation modular framework to help address the security issues lurking in M-Commerce systems being used by marginalised rural community members. The research commences with a literature survey carried out to establish security aspects related to M-Commerce and to determine requirements for a security framework. The framework classifies M-Commerce security threat-vulnerability-risks into four levels: human behaviour and mobile device interaction security, mobile device security, M-Commerce access channel security, wireless network access security. This is followed by a review of the supporting structures or related frameworks that the proposed framework could leverage to address security issues on M-Commerce systems as ICT4D initiatives. The proposed security framework based on the requirements discovered is then presented. As a proof-of-concept, a case study was undertaken at the Siyakhula Living Lab at Dwesa in the Eastern Cape province of South Africa in order to validate the components of the proposed framework. Following the application of the framework in a case study, it can be argued that the proposed security framework allows for secure transacting by marginalised users using M-Commerce initiatives. The security framework is therefore useful in addressing the identified security requirements of M-Commerce in ICT4D contexts.
- Full Text:
- Date Issued: 2014
Development of conservation methods for gunnera perpensa l.: an overexploited medicinal plant in the Eastern Cape, South Africa
- Authors: Chigor, Chinyere Blessing
- Date: 2014
- Subjects: Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11311 , http://hdl.handle.net/10353/d1019832 , Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Description: South Africa, many plants which are used in traditional medicines are collected from wild populations. The high demand for trade and use of these medicinal plants place an enormous pressure on their natural populations, especially because they are indiscriminately harvested. The most affected of these plant species are those harvested from their underground parts, among which is Gunnera perpensa L. Gunnera perpensa is of considerable ethnobotanical interest in traditional medicine because of its wide usage. The rhizomes are widely used and indiscriminately collected in large quantities from the wild to meet the ever increasing demand in traditional medicine markets. As a result, this valuable medicinal plant species is being endangered. According to the Red List of South African Plants, the conservation status of G. perpensa has been listed as ‘declining’. The ethnobotanical survey conducted as part of this research confirms the plant species as threatened. It is, therefore, important to develop propagation and conservation strategies for this medicinal plant. Clonal propagation of G. perpensa was conducted using varying lengths of the rhizome (1, 2, 3, 4 and 5 cm) segments as propagules. While regeneration was possible with all the rhizome lengths, most of the growth parameters were significantly higher in the 5 cm rhizomes than the other rhizome segments. The appropriate planting depth for the rhizomes was also determined and 4 or 5 cm planting depths were found appropriate. No significant difference was observed in the growth parameters amongst the planting depths; nevertheless, 4 cm depth gave higher growth and yield. The results of this study show that regenerating G. perpensa.
- Full Text:
- Date Issued: 2014
- Authors: Chigor, Chinyere Blessing
- Date: 2014
- Subjects: Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11311 , http://hdl.handle.net/10353/d1019832 , Gunnera -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Medical anthropology -- South Africa -- Eastern Cape , Medical policy -- South Africa -- Eastern Cape
- Description: South Africa, many plants which are used in traditional medicines are collected from wild populations. The high demand for trade and use of these medicinal plants place an enormous pressure on their natural populations, especially because they are indiscriminately harvested. The most affected of these plant species are those harvested from their underground parts, among which is Gunnera perpensa L. Gunnera perpensa is of considerable ethnobotanical interest in traditional medicine because of its wide usage. The rhizomes are widely used and indiscriminately collected in large quantities from the wild to meet the ever increasing demand in traditional medicine markets. As a result, this valuable medicinal plant species is being endangered. According to the Red List of South African Plants, the conservation status of G. perpensa has been listed as ‘declining’. The ethnobotanical survey conducted as part of this research confirms the plant species as threatened. It is, therefore, important to develop propagation and conservation strategies for this medicinal plant. Clonal propagation of G. perpensa was conducted using varying lengths of the rhizome (1, 2, 3, 4 and 5 cm) segments as propagules. While regeneration was possible with all the rhizome lengths, most of the growth parameters were significantly higher in the 5 cm rhizomes than the other rhizome segments. The appropriate planting depth for the rhizomes was also determined and 4 or 5 cm planting depths were found appropriate. No significant difference was observed in the growth parameters amongst the planting depths; nevertheless, 4 cm depth gave higher growth and yield. The results of this study show that regenerating G. perpensa.
- Full Text:
- Date Issued: 2014
Diet and microhabitat use of the woodland dormouse Graphiurus murinus at the Great Fish River Reserve, Eastern Cape, South Africa
- Authors: Lamani, Siviwe
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11797 , http://hdl.handle.net/10353/d1019854
- Description: The diet of the woodland dormouse Graphiurus murinus was studied in a riverine Combretum forest at the Great Fish River Reserve (Eastern Cape, South Africa). Food remains were collected seasonally from a maximum of 45 different nest boxes between December 2010 and November 2011. An overall mean of 1.32 ± 0.51 food categories (range 1–4) were identified in each nest box used as “larder” during the year. Dietary diversity and standardized diet breadth were low to intermediate, with a peak in summer and a nadir in winter. In terms of percentage occurrence, arthropods were dominant (99%) in all seasons, followed by molluscs (16%) and fruits (14%). When relative percentage occurrence and percentage weight were considered, arthropods were still dominant, but a slight decrease was observed in summer. Besides spiders (order Araneae), nine arthropod families were found in the diet of the woodland dormouse; Tenebrionidae (40%), Spirostreptidae (30%), Carabidae (15%) and Blattidae (14%) were the most dominant families in terms of percentage weight. Grewia robusta and Ziziphus mucronata were the only fruit species present in the diet. Pianka’s diet overlap indices were very high (>0.93), indicating that the diet of the woodland dormouse was similar between pairs of seasons. This study also investigated whether woodland dormice Graphiurus murinus positively select or avoid specific microhabitat types or structures, and whether a set of predictor variables related to microhabitat characteristics can explain the presence and rates of visits to specific trapping stations. Trapping was conducted seasonally, over 5 days, between June 2011 and April 2012. A grid of 96 stations (16 rows × 6 lines) was established. Trap stations were set at 10-m intervals. At each station two Sherman traps were placed. The 192 traps were distributed relatively equitably among four height categories (0–0.5 m, 0.51–1 m, 1.01–1.5 m, and 1.51–2.5 m). On average, trapping success was 4.70 ± 4.17 dormice per 100 traps. Dormice were trapped at an average height of 136 ± 64 cm, which was significantly higher than the average height at which traps were set (99 ± 75 cm). Bonferroni Z tests indicated that dormice positively selected areas with high canopy cover and connectivity, possibly to decrease predation risk. Generalized Linear Models showed that trap use and numbers of visits and different animals caught were positively associated with a high arboreal connectivity, hence supporting the hypothesis that woodland dormice may depend on wooden “corridors” for their movements.
- Full Text:
- Date Issued: 2014
- Authors: Lamani, Siviwe
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11797 , http://hdl.handle.net/10353/d1019854
- Description: The diet of the woodland dormouse Graphiurus murinus was studied in a riverine Combretum forest at the Great Fish River Reserve (Eastern Cape, South Africa). Food remains were collected seasonally from a maximum of 45 different nest boxes between December 2010 and November 2011. An overall mean of 1.32 ± 0.51 food categories (range 1–4) were identified in each nest box used as “larder” during the year. Dietary diversity and standardized diet breadth were low to intermediate, with a peak in summer and a nadir in winter. In terms of percentage occurrence, arthropods were dominant (99%) in all seasons, followed by molluscs (16%) and fruits (14%). When relative percentage occurrence and percentage weight were considered, arthropods were still dominant, but a slight decrease was observed in summer. Besides spiders (order Araneae), nine arthropod families were found in the diet of the woodland dormouse; Tenebrionidae (40%), Spirostreptidae (30%), Carabidae (15%) and Blattidae (14%) were the most dominant families in terms of percentage weight. Grewia robusta and Ziziphus mucronata were the only fruit species present in the diet. Pianka’s diet overlap indices were very high (>0.93), indicating that the diet of the woodland dormouse was similar between pairs of seasons. This study also investigated whether woodland dormice Graphiurus murinus positively select or avoid specific microhabitat types or structures, and whether a set of predictor variables related to microhabitat characteristics can explain the presence and rates of visits to specific trapping stations. Trapping was conducted seasonally, over 5 days, between June 2011 and April 2012. A grid of 96 stations (16 rows × 6 lines) was established. Trap stations were set at 10-m intervals. At each station two Sherman traps were placed. The 192 traps were distributed relatively equitably among four height categories (0–0.5 m, 0.51–1 m, 1.01–1.5 m, and 1.51–2.5 m). On average, trapping success was 4.70 ± 4.17 dormice per 100 traps. Dormice were trapped at an average height of 136 ± 64 cm, which was significantly higher than the average height at which traps were set (99 ± 75 cm). Bonferroni Z tests indicated that dormice positively selected areas with high canopy cover and connectivity, possibly to decrease predation risk. Generalized Linear Models showed that trap use and numbers of visits and different animals caught were positively associated with a high arboreal connectivity, hence supporting the hypothesis that woodland dormice may depend on wooden “corridors” for their movements.
- Full Text:
- Date Issued: 2014
Diet of the yellow mongoose (Cynictis penicillata) in the Albany Thicket Biome of South Africa
- Authors: Bizani, Mfundo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11796 , http://hdl.handle.net/10353/d1019840
- Description: The dietary habits of the yellow mongoose Cynictis penicillata were studied in the Albany Thicket Biome of South Africa (Great Fish River Reserve, Eastern Cape). The diet was investigated through the analysis of 1,056 scats that were sampled over a period of 7 years (2005−2009 and 2011−2012) mainly in three similar sites (Kelarny, Grasslands and Junction 10) that were used by at least three families or groups of yellow mongooses. Scats were collected near latrine sites, labelled and stored in a freezer. In the laboratory, scats were oven dried for a period of 24 hours at 50 C. Diet was determined by identifying undigested food remains in the scats. Hair samples were examined under the compound microscope to identify which mammals were ingested. In the field, both arthropod and small mammal abundance were determined in order to evaluate whether yellow mongooses are opportunistic or specialist feeders. Furthermore, inter-annual (2006–2008) and inter-group/inter-site variations in the diet were assessed. Based on faecal analysis, arthropods were the principal prey, while small mammals acted as supplementary food item. Other food categories like vegetation, reptiles and birds were only ingested or preyed upon infrequently. Intermediate dietary diversity, and low standardised diet breadth indices were obtained for all seasons, as well as for the whole sampling period. The diet overlaps calculated for pairs of seasons were very high and did not differ substantially. However, the diet of the yellow mongoose varied seasonally, yearly and between groups (sites), mostly due to variations in arthropod and small mammal consumption. Food availability displayed an increase in biomass of both small mammals and arthropods in summer and autumn. Results obtained in this study could suggest that the yellow mongoose at the GFRR is insectivorous by preferring to feed on insects (and arthropods in general) when both insects and rodents are abundant. However the fact that its diet varies both seasonally, yearly and locally, as well as the presence of remains of other food categories in the scats, indicates that this species is rather an opportunistic, generalist feeder than an insect specialist.
- Full Text:
- Date Issued: 2014
- Authors: Bizani, Mfundo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Zoology)
- Identifier: vital:11796 , http://hdl.handle.net/10353/d1019840
- Description: The dietary habits of the yellow mongoose Cynictis penicillata were studied in the Albany Thicket Biome of South Africa (Great Fish River Reserve, Eastern Cape). The diet was investigated through the analysis of 1,056 scats that were sampled over a period of 7 years (2005−2009 and 2011−2012) mainly in three similar sites (Kelarny, Grasslands and Junction 10) that were used by at least three families or groups of yellow mongooses. Scats were collected near latrine sites, labelled and stored in a freezer. In the laboratory, scats were oven dried for a period of 24 hours at 50 C. Diet was determined by identifying undigested food remains in the scats. Hair samples were examined under the compound microscope to identify which mammals were ingested. In the field, both arthropod and small mammal abundance were determined in order to evaluate whether yellow mongooses are opportunistic or specialist feeders. Furthermore, inter-annual (2006–2008) and inter-group/inter-site variations in the diet were assessed. Based on faecal analysis, arthropods were the principal prey, while small mammals acted as supplementary food item. Other food categories like vegetation, reptiles and birds were only ingested or preyed upon infrequently. Intermediate dietary diversity, and low standardised diet breadth indices were obtained for all seasons, as well as for the whole sampling period. The diet overlaps calculated for pairs of seasons were very high and did not differ substantially. However, the diet of the yellow mongoose varied seasonally, yearly and between groups (sites), mostly due to variations in arthropod and small mammal consumption. Food availability displayed an increase in biomass of both small mammals and arthropods in summer and autumn. Results obtained in this study could suggest that the yellow mongoose at the GFRR is insectivorous by preferring to feed on insects (and arthropods in general) when both insects and rodents are abundant. However the fact that its diet varies both seasonally, yearly and locally, as well as the presence of remains of other food categories in the scats, indicates that this species is rather an opportunistic, generalist feeder than an insect specialist.
- Full Text:
- Date Issued: 2014
Effect of irrigation farming potential on commercialization of smallholder farming in the Eastern Cape Province of South Africa
- Authors: Sipoko, Nomava
- Date: 2014
- Subjects: Irrigation farming -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Agriculture -- Economic aspects
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11218 , http://hdl.handle.net/10353/d1019772 , Irrigation farming -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Agriculture -- Economic aspects
- Description: Enhancement of smallholder production to improve rural livelihood is an important policy goal in developing countries. Research findings indicate that smallholder production can be improved through establishment of new smallholder irrigation schemes, and the rehabilitation of abandoned ones. Smallholder irrigation has a potential to contribute significantly in shifting smallholder farming to commercial farming. Although the roles of irrigating farmers are clearly defined, smallholder farmer’s development results in South Africa have been disappointing. The performance of smallholder irrigation is unsatisfactory. Smallholder irrigation has failed to improve the standard of living and livelihoods of smallholder farmers in South Africa. The majority of farmers are still producing at subsistence level. This study, therefore, aimed to contribute to smallholder irrigation literature in two ways; firstly by evaluating the extent of irrigation participation of smallholder farmers towards commercialization in the study areas. The study also examined the determinants of irrigation participation among smallholder farmers. A sample of 80 households was drawn by random sampling of smallholders in four villages as follows: 40 respondents from Mgxabakazi and Dinizulu villages and 40 respondents from Ncorha flats and Tshatshu. The sample included both irrigators and non-irrigators. Descriptive analysis shows that irrigators had better production and wellbeing than non-irrigators. For the inferential analysis of the data, two models were employed namely, Binary Logistic Regression Model (BRM) and Truncated Regression Model (TRM). The Binary Regression model was used to predict the probability of farmers participating in irrigation schemes. Whether or not a farmer participated in irrigation was introduced as the binary dependent or response variable that could be explained by a range of explanatory or predictor variables such as source of water, land size, ability to sustain business, membership in the scheme, market access, availability of the irrigation system, willingness to irrigate, farming type commercial or subsistence and institutional support services. From these predictor variables, being part of the irrigation, ability to sustain business and market were found to be factors influencing farmer’s decision to participate. The second model required the in-depth investigation of the influence of irrigation participation as reflected by extent of commercialization. In order to do this, the level of commercialization was measured by calculating Household Commercialization Index. Then the truncated regression model (TR) was used to test the factors that affect the level of commercialization for the farmers who are participating in the irrigation schemes.Age, irrigated land, willingness to commercialize and gross value of production were found to exert strong influence on the level of commercialization among farmers participating in irrigation. The study recommends that investments in smallholder irrigation should receive high priority, with emphasis on collective action, promotion of contract farming and strengthening the support services from government and the private sector, and ensuring enhanced access to market to all farmers.
- Full Text:
- Date Issued: 2014
- Authors: Sipoko, Nomava
- Date: 2014
- Subjects: Irrigation farming -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Agriculture -- Economic aspects
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11218 , http://hdl.handle.net/10353/d1019772 , Irrigation farming -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Agriculture -- Economic aspects
- Description: Enhancement of smallholder production to improve rural livelihood is an important policy goal in developing countries. Research findings indicate that smallholder production can be improved through establishment of new smallholder irrigation schemes, and the rehabilitation of abandoned ones. Smallholder irrigation has a potential to contribute significantly in shifting smallholder farming to commercial farming. Although the roles of irrigating farmers are clearly defined, smallholder farmer’s development results in South Africa have been disappointing. The performance of smallholder irrigation is unsatisfactory. Smallholder irrigation has failed to improve the standard of living and livelihoods of smallholder farmers in South Africa. The majority of farmers are still producing at subsistence level. This study, therefore, aimed to contribute to smallholder irrigation literature in two ways; firstly by evaluating the extent of irrigation participation of smallholder farmers towards commercialization in the study areas. The study also examined the determinants of irrigation participation among smallholder farmers. A sample of 80 households was drawn by random sampling of smallholders in four villages as follows: 40 respondents from Mgxabakazi and Dinizulu villages and 40 respondents from Ncorha flats and Tshatshu. The sample included both irrigators and non-irrigators. Descriptive analysis shows that irrigators had better production and wellbeing than non-irrigators. For the inferential analysis of the data, two models were employed namely, Binary Logistic Regression Model (BRM) and Truncated Regression Model (TRM). The Binary Regression model was used to predict the probability of farmers participating in irrigation schemes. Whether or not a farmer participated in irrigation was introduced as the binary dependent or response variable that could be explained by a range of explanatory or predictor variables such as source of water, land size, ability to sustain business, membership in the scheme, market access, availability of the irrigation system, willingness to irrigate, farming type commercial or subsistence and institutional support services. From these predictor variables, being part of the irrigation, ability to sustain business and market were found to be factors influencing farmer’s decision to participate. The second model required the in-depth investigation of the influence of irrigation participation as reflected by extent of commercialization. In order to do this, the level of commercialization was measured by calculating Household Commercialization Index. Then the truncated regression model (TR) was used to test the factors that affect the level of commercialization for the farmers who are participating in the irrigation schemes.Age, irrigated land, willingness to commercialize and gross value of production were found to exert strong influence on the level of commercialization among farmers participating in irrigation. The study recommends that investments in smallholder irrigation should receive high priority, with emphasis on collective action, promotion of contract farming and strengthening the support services from government and the private sector, and ensuring enhanced access to market to all farmers.
- Full Text:
- Date Issued: 2014
Effect of pre-slaughter stress of pigs on the levels of cortisol, creatine kinase and their subsequent relationship with pork quality
- Authors: Nzolo, Jama
- Date: 2014
- Subjects: Slaughtering and slaughter-houses , Pork -- Quality , Swine -- Handling , Livestock -- Handling , Creatine kinase
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11837 , http://hdl.handle.net/10353/d1021287 , Slaughtering and slaughter-houses , Pork -- Quality , Swine -- Handling , Livestock -- Handling , Creatine kinase
- Description: The study was conducted to determine the effect of pre-slaughter stress of pigs on the levels of cortisol, creatine kinase (CK) and their subsequent relationship with pork quality. From our knowledge, there is paucity of information on transportation, lairage duration and sex effects on saliva cortisol and its relation with serum cortisol, urine cortisol and other meat quality traits. Stage one of the study assessed the effect of sex and time to slaughter (transport and lairage duration) on the levels of cortisol and CK in crossbred pigs. The second stage of the study evaluated the effect of sex and lairage duration on pork quality. The trials comprised of 60 22-weeks old commercial crossbred pigs [(30 boars vs. 30 gilts) with an average body weight of 76.9kg for gilts and 78.3kg for boars. Thirty pigs (15 Boars vs. 15 Gilts) were slaughtered on arrival after a 120km road journey and the other 30, after travelling the same road and distance, were slaughtered after having been in the lairage for 20 hours. Saliva samples were obtained during three time periods: between 07:00-10:00 on the day before the journey, on arrival at the abattoir and after lairage. Levels of cortisol in serum and urine and CK in serum samples collected at slaughter were determined. The samples (saliva and serum) were centrifuged at 20oC for 10 min at 3550 x g and stored at -20oC in separate vials until analysis. Pork quality was assessed using muscle pH, colour, thawing and cooking losses and Warner-Bratzler Shear Force. Correlations between cortisol levels in saliva, serum and urine and meat quality were assessed. The effect of sex and time to slaughter on saliva cortisol was significant. Statistical analysis showed significant interaction of sex by time to slaughter on serum cortisol. It was only the effect of sex that demonstrated higher (P <0.05) serum creatine kinase levels in gilts. Likewise, urine cortisol was influenced (P <0.05) only by time to slaughter. Saliva cortisol after transportation (r = 0.52) was correlated (P <0.05) with urine cortisol. The study suggests that there are greater responses of the Hypothalamic-pituitary-adrenal axis following time to slaughter (transport and lairage duration) between gilts and boars. This can be used in measuring cortisol in saliva, serum and urine, and serum creatine kinase to determine stress levels in pigs. Besides the lightness (L*) colour value which was significantly lower (P <0.05) in meat from gilts than from boars, the results of this study showed no interaction or individual effect (sex or lairage duration) on pH and other colour measurements. Meat cooking loss was affected (P <0.05) by gender x lairage interaction. Effect of lairage duration (as an individual effect) on the measured meat quality traits was not significant (P <0.05). Correlation analysis showed significant (P <0.05) negative relation between baseline saliva cortisol (r = -0.40) and the pork L* value. Saliva cortisol after lairage duration (r = -0.38 and r = 0.38) was correlated (P <0.05) with pH45 and pork a* value, respectively. Serum cortisol (r = -0.35) was negatively correlated (P <0.05) with pH45. Moreover, there were negative correlations (P <0.05) between saliva cortisol after transportation (r = -0.35), saliva cortisol after lairage duration (r = -0.44), serum cortisol (r = -0.40) and meat cooking loss. The study suggests that cortisol in saliva and serum can be used to determine effect of time to slaughter (transport and lairage duration) on meat quality traits from gilts and boars. Keywords: Boars; gilts; saliva cortisol; serum cortisol; serum creatine kinase; urine cortisol.
- Full Text:
- Date Issued: 2014
- Authors: Nzolo, Jama
- Date: 2014
- Subjects: Slaughtering and slaughter-houses , Pork -- Quality , Swine -- Handling , Livestock -- Handling , Creatine kinase
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11837 , http://hdl.handle.net/10353/d1021287 , Slaughtering and slaughter-houses , Pork -- Quality , Swine -- Handling , Livestock -- Handling , Creatine kinase
- Description: The study was conducted to determine the effect of pre-slaughter stress of pigs on the levels of cortisol, creatine kinase (CK) and their subsequent relationship with pork quality. From our knowledge, there is paucity of information on transportation, lairage duration and sex effects on saliva cortisol and its relation with serum cortisol, urine cortisol and other meat quality traits. Stage one of the study assessed the effect of sex and time to slaughter (transport and lairage duration) on the levels of cortisol and CK in crossbred pigs. The second stage of the study evaluated the effect of sex and lairage duration on pork quality. The trials comprised of 60 22-weeks old commercial crossbred pigs [(30 boars vs. 30 gilts) with an average body weight of 76.9kg for gilts and 78.3kg for boars. Thirty pigs (15 Boars vs. 15 Gilts) were slaughtered on arrival after a 120km road journey and the other 30, after travelling the same road and distance, were slaughtered after having been in the lairage for 20 hours. Saliva samples were obtained during three time periods: between 07:00-10:00 on the day before the journey, on arrival at the abattoir and after lairage. Levels of cortisol in serum and urine and CK in serum samples collected at slaughter were determined. The samples (saliva and serum) were centrifuged at 20oC for 10 min at 3550 x g and stored at -20oC in separate vials until analysis. Pork quality was assessed using muscle pH, colour, thawing and cooking losses and Warner-Bratzler Shear Force. Correlations between cortisol levels in saliva, serum and urine and meat quality were assessed. The effect of sex and time to slaughter on saliva cortisol was significant. Statistical analysis showed significant interaction of sex by time to slaughter on serum cortisol. It was only the effect of sex that demonstrated higher (P <0.05) serum creatine kinase levels in gilts. Likewise, urine cortisol was influenced (P <0.05) only by time to slaughter. Saliva cortisol after transportation (r = 0.52) was correlated (P <0.05) with urine cortisol. The study suggests that there are greater responses of the Hypothalamic-pituitary-adrenal axis following time to slaughter (transport and lairage duration) between gilts and boars. This can be used in measuring cortisol in saliva, serum and urine, and serum creatine kinase to determine stress levels in pigs. Besides the lightness (L*) colour value which was significantly lower (P <0.05) in meat from gilts than from boars, the results of this study showed no interaction or individual effect (sex or lairage duration) on pH and other colour measurements. Meat cooking loss was affected (P <0.05) by gender x lairage interaction. Effect of lairage duration (as an individual effect) on the measured meat quality traits was not significant (P <0.05). Correlation analysis showed significant (P <0.05) negative relation between baseline saliva cortisol (r = -0.40) and the pork L* value. Saliva cortisol after lairage duration (r = -0.38 and r = 0.38) was correlated (P <0.05) with pH45 and pork a* value, respectively. Serum cortisol (r = -0.35) was negatively correlated (P <0.05) with pH45. Moreover, there were negative correlations (P <0.05) between saliva cortisol after transportation (r = -0.35), saliva cortisol after lairage duration (r = -0.44), serum cortisol (r = -0.40) and meat cooking loss. The study suggests that cortisol in saliva and serum can be used to determine effect of time to slaughter (transport and lairage duration) on meat quality traits from gilts and boars. Keywords: Boars; gilts; saliva cortisol; serum cortisol; serum creatine kinase; urine cortisol.
- Full Text:
- Date Issued: 2014
Effects of dietary inclusion of Moringa oleifera leaf meal on growth performance, physico-chemical attributes, oxidative stability and sensory quality of pork
- Authors: Nduku, Xola Pauline
- Date: 2014
- Subjects: Pork -- Quality , Food -- Sensory evaluation , Fatty acids , Moringa , Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11836 , http://hdl.handle.net/10353/d1021281 , Pork -- Quality , Food -- Sensory evaluation , Fatty acids , Moringa , Meat -- Quality
- Description: The objective of the study was to determine growth performance, physico-chemical attributes, oxidative stability and sensory quality of pork from pigs fed one of three dietary treatments, eac containing 0%, 2.5% or 5% (T1, T2 and T3, respectively) Moringa oleifera leaf meal (MOLM). Dietary treatments were formulated to be isonitrogenous and isoenergetic for weaner (6 – 8 weeks) and grower (9 – 13 weeks) phases. Twelve Large White (LW) and 12 Kolbroek (KB) male pigs at 6 weeks of age, initially weighing an average 10 kg, were randomly allocated to one of the dietary treatments, each with four replicates, in individual pens. Feed and water were offered ad libitum. The Longissimus thoracis et lumborum (LTL) muscle of each carcass (n = 24) was sampled for meat quality and fatty acid analyses. Breed differences in measured parameters were observed. In pigs receiving 5% MOLM, the LW had significantly the highest ADFI (P<0.05) than KB pigs. In pigs receiving 2.5% and 5% MOLM, backfat thickness was significantly highest (P<0.05) compared to those receiving 0% MOML. Dietary inclusion of MOLM had no significant effects (P>0.05) on the physico-chemical quality of pork from LW pigs; although it significantly (P<0.05) increased a* and reduced WBSF values in pork from KB pigs. Pork from LW pigs receiving 5% MOLM had significantly increased (P<0.05) n-3 content of the subcutaneous tissue of LW pigs compared to KB, and also when compread to other treatment groups. In both breeds, the composition of PUFA: SFA and n-6: n-3 in the subcutaneous adipose tissue was significantly (P<0.05) lower in T2 and T3 than in T1. The n-3 levels for pork muscle from LW pigs receiving 2.5% and 5% MOLM, and from KB pigs receiving 5% MOLM, were significantly (P<0.05) lower. Inclusions of MOLM significantly (P<0.05) reduced the n-6: n-3 fatty acids in pork from both LW pigs and KB pigs. Consumer scores on sensory attributes (aroma intensity, initial impression of juiciness, first bite, sustained impression of juiciness, muscle fibre and overall tenderness and overall flavor intensity) significantly (P<0.05) increased as the level of MOLM inclusion in the diet increased; and higher scores were observed in fried meat than in boiled for most sensory attributes. It may be concluded that inclusion of MOLM in pig diets up to 5% improved the ADFI, a*, tenderness of pork without adversely affecting the FCR and other physico-chemical quality attributes; and resulted in desired increase in levels of n-3 and reduced the n-6: n-3 fatty acid ratio.
- Full Text:
- Date Issued: 2014
- Authors: Nduku, Xola Pauline
- Date: 2014
- Subjects: Pork -- Quality , Food -- Sensory evaluation , Fatty acids , Moringa , Meat -- Quality
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11836 , http://hdl.handle.net/10353/d1021281 , Pork -- Quality , Food -- Sensory evaluation , Fatty acids , Moringa , Meat -- Quality
- Description: The objective of the study was to determine growth performance, physico-chemical attributes, oxidative stability and sensory quality of pork from pigs fed one of three dietary treatments, eac containing 0%, 2.5% or 5% (T1, T2 and T3, respectively) Moringa oleifera leaf meal (MOLM). Dietary treatments were formulated to be isonitrogenous and isoenergetic for weaner (6 – 8 weeks) and grower (9 – 13 weeks) phases. Twelve Large White (LW) and 12 Kolbroek (KB) male pigs at 6 weeks of age, initially weighing an average 10 kg, were randomly allocated to one of the dietary treatments, each with four replicates, in individual pens. Feed and water were offered ad libitum. The Longissimus thoracis et lumborum (LTL) muscle of each carcass (n = 24) was sampled for meat quality and fatty acid analyses. Breed differences in measured parameters were observed. In pigs receiving 5% MOLM, the LW had significantly the highest ADFI (P<0.05) than KB pigs. In pigs receiving 2.5% and 5% MOLM, backfat thickness was significantly highest (P<0.05) compared to those receiving 0% MOML. Dietary inclusion of MOLM had no significant effects (P>0.05) on the physico-chemical quality of pork from LW pigs; although it significantly (P<0.05) increased a* and reduced WBSF values in pork from KB pigs. Pork from LW pigs receiving 5% MOLM had significantly increased (P<0.05) n-3 content of the subcutaneous tissue of LW pigs compared to KB, and also when compread to other treatment groups. In both breeds, the composition of PUFA: SFA and n-6: n-3 in the subcutaneous adipose tissue was significantly (P<0.05) lower in T2 and T3 than in T1. The n-3 levels for pork muscle from LW pigs receiving 2.5% and 5% MOLM, and from KB pigs receiving 5% MOLM, were significantly (P<0.05) lower. Inclusions of MOLM significantly (P<0.05) reduced the n-6: n-3 fatty acids in pork from both LW pigs and KB pigs. Consumer scores on sensory attributes (aroma intensity, initial impression of juiciness, first bite, sustained impression of juiciness, muscle fibre and overall tenderness and overall flavor intensity) significantly (P<0.05) increased as the level of MOLM inclusion in the diet increased; and higher scores were observed in fried meat than in boiled for most sensory attributes. It may be concluded that inclusion of MOLM in pig diets up to 5% improved the ADFI, a*, tenderness of pork without adversely affecting the FCR and other physico-chemical quality attributes; and resulted in desired increase in levels of n-3 and reduced the n-6: n-3 fatty acid ratio.
- Full Text:
- Date Issued: 2014
Effects of oats and vetch cover crops on light organic matter fractions and activities of selected enzymes in an irrigated maize based conservation agriculture system on Alice Jozini Ecotope in the Eastern Cape, South Africa
- Authors: Mukumbareza, Caroline
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11872 , http://hdl.handle.net/10353/d1019815
- Description: Low soil fertility in the Eastern Cape Province (EC) is attributed to poor agricultural management, which reduces organic matter, among other factors. Conservation agriculture (CA), consisting of no-till, soil cover and rotations, is being promoted to improve soil quality and productivity. Soil biological parameters respond to the overall effects of management on the physical and chemical components of soil. This study was conducted to evaluate the effects of oat (Avena sativa) and grazing vetch (Vicia dasycarpa) cover crops on soil biological activity after five years under CA and evaluate light organic matter fractions, MBC and activities of selected enzymes as early indicators of organic matter build up under in no-till maize based CA system. The study was based on soil samples collected from a five year trial with rotations of maize and sole covercrops and two younger trials (4 and 28 months) with oat and grazing vetch bicultures. In the five year old trial, oat and grazing vetch were planted at four fertiliser regimes (i) Fertilizer applied to cover crops and maize (F1), (ii) fertilizer applied to cover crops only (F2), (iii) fertilizer applied to maize only (F3) and (iv) no fertilizer applied (F4)) to give a 2 × 4 factorial plus control laid out in a randomized complete block design (RCBD) with three replications. Fertilizer was applied at 10 kg P ha-1, as a compound (6.7% N; 10% P; 13.3% K) at planting and grazing vetch was inoculated with Rhizobium legunominosarium biovar viciae. Oat was top dressed using limestone ammonium nitrate (LAN – 28% N) at 7 weeks after planting (WAP) to make a total of 45 kg N ha-1. Three weeks after termination of the cover crops, all plots were split in half and maize was planted and fertilizer applied at 0 and 60 N kg ha-1. A third of the N was applied at planting (6.7% N; 10% P; 13.3% K). In the biculture trials, the treatments were 90% oat + 10% vetch, 70% oat + 30% vetch, 50% oat+ 50% vetch, 100% vetch and 100% oat and laid out in a RCBD with three replicates. Only basal fertilizer was applied to the cover crop at planting at 13.34 kg N ha-1, 20 kg P ha-1 and 26.66 kg K ha-1 using 2:3:4 (30 + 0.5% Zn) compound fertiliser. After cover crop termination, SC701 maize variety was planted, and fertilised at 60 kg N ha-1 with a third of the N applied as a basal. In the five year old trial, oat and vetch gave significantly (P < 0.05) higher MBC and activities of all soil enzymes measured than the weedy fallow at 0-5 and 5-20 cm depths. Fertilization of cover crop (F2) and maize (F3) gave similar MBC. The F4 in cover crops gave similar dehydrogenase activity with F3 under weedy fallow and that for vetch rotation was the same for F3 in oat. The F4 for grazing vetch had similar β-glucosidase activity as F1 and similar urease activity as F1, F2 and F3 of oat rotations. Acid and alkaline activity in F1 had similar results to F2. In the younger trials, biculture treatments did not improve total C, and N when compared with the weedy fallow. Dehydrogenase, β-glucosidase, arylsulphatase and alkaline phosphatase activities were higher in the 28 month trial compared to the 4 month one while urease was higher in the 4-month old trial. Treatments with more than 50% oat content had higher acid phosphatase activity in the 4- than 28 month old trial. Effects of cover crop, as the main factor, was significant in all enzymes (P < 0.05), with 70% oat + 30% vetch treatment having the highest dehydrogenase and arylsulphatase while for alkaline phosphatase it had similar results to 90% oat + 10% vetch. For β-glucosidase and urease, effects of cover crop as the main factor were also significant with sole vetch giving the highest activity for both enzymes. Acid phosphatase activity was highest in sole oat. Particulate OM was highest in the 100% oat treatment and declined with decrease in the proportion of oat in the biculture. The 50% oat + 50% vetch treatment had similar POM to the 70% oat +30% vetch in the 4 month old trial and to the 90% oat + 10% vetch in the 28 months old trial in the 0-5 cm depth (P < 0.05). In the 5-20 cm depth, the 70% oat +30% vetch treatment had similar POM to the 90% oat + 10% vetch in the 28 month old trial. The 70% oat+30% vetch had greatest WSC and MBC followed by the 90% oat +10% vetch, with the 50% oat + 50% vetch being similar to 100% vetch and 100% oat (MBC only). The 28 months old trial had greater POM and WSC than the 4 months trial. The findings of this study imply that the use of grazing vetch and fertilization of cover crops only improves soil biological activity, represented by MBC and enzyme activities, after 5 years of maize-cover crop rotations in low input conservation agriculture system. Bicultures, particularly the 70% oat + 30% vetch, work better than their sole crops in improving organic matter fractions, MBC and enzyme activities and that POM, WSC, MBC, enzyme activities are useful early indicators of soil organic matter build-up of CA systems.
- Full Text:
- Date Issued: 2014
- Authors: Mukumbareza, Caroline
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11872 , http://hdl.handle.net/10353/d1019815
- Description: Low soil fertility in the Eastern Cape Province (EC) is attributed to poor agricultural management, which reduces organic matter, among other factors. Conservation agriculture (CA), consisting of no-till, soil cover and rotations, is being promoted to improve soil quality and productivity. Soil biological parameters respond to the overall effects of management on the physical and chemical components of soil. This study was conducted to evaluate the effects of oat (Avena sativa) and grazing vetch (Vicia dasycarpa) cover crops on soil biological activity after five years under CA and evaluate light organic matter fractions, MBC and activities of selected enzymes as early indicators of organic matter build up under in no-till maize based CA system. The study was based on soil samples collected from a five year trial with rotations of maize and sole covercrops and two younger trials (4 and 28 months) with oat and grazing vetch bicultures. In the five year old trial, oat and grazing vetch were planted at four fertiliser regimes (i) Fertilizer applied to cover crops and maize (F1), (ii) fertilizer applied to cover crops only (F2), (iii) fertilizer applied to maize only (F3) and (iv) no fertilizer applied (F4)) to give a 2 × 4 factorial plus control laid out in a randomized complete block design (RCBD) with three replications. Fertilizer was applied at 10 kg P ha-1, as a compound (6.7% N; 10% P; 13.3% K) at planting and grazing vetch was inoculated with Rhizobium legunominosarium biovar viciae. Oat was top dressed using limestone ammonium nitrate (LAN – 28% N) at 7 weeks after planting (WAP) to make a total of 45 kg N ha-1. Three weeks after termination of the cover crops, all plots were split in half and maize was planted and fertilizer applied at 0 and 60 N kg ha-1. A third of the N was applied at planting (6.7% N; 10% P; 13.3% K). In the biculture trials, the treatments were 90% oat + 10% vetch, 70% oat + 30% vetch, 50% oat+ 50% vetch, 100% vetch and 100% oat and laid out in a RCBD with three replicates. Only basal fertilizer was applied to the cover crop at planting at 13.34 kg N ha-1, 20 kg P ha-1 and 26.66 kg K ha-1 using 2:3:4 (30 + 0.5% Zn) compound fertiliser. After cover crop termination, SC701 maize variety was planted, and fertilised at 60 kg N ha-1 with a third of the N applied as a basal. In the five year old trial, oat and vetch gave significantly (P < 0.05) higher MBC and activities of all soil enzymes measured than the weedy fallow at 0-5 and 5-20 cm depths. Fertilization of cover crop (F2) and maize (F3) gave similar MBC. The F4 in cover crops gave similar dehydrogenase activity with F3 under weedy fallow and that for vetch rotation was the same for F3 in oat. The F4 for grazing vetch had similar β-glucosidase activity as F1 and similar urease activity as F1, F2 and F3 of oat rotations. Acid and alkaline activity in F1 had similar results to F2. In the younger trials, biculture treatments did not improve total C, and N when compared with the weedy fallow. Dehydrogenase, β-glucosidase, arylsulphatase and alkaline phosphatase activities were higher in the 28 month trial compared to the 4 month one while urease was higher in the 4-month old trial. Treatments with more than 50% oat content had higher acid phosphatase activity in the 4- than 28 month old trial. Effects of cover crop, as the main factor, was significant in all enzymes (P < 0.05), with 70% oat + 30% vetch treatment having the highest dehydrogenase and arylsulphatase while for alkaline phosphatase it had similar results to 90% oat + 10% vetch. For β-glucosidase and urease, effects of cover crop as the main factor were also significant with sole vetch giving the highest activity for both enzymes. Acid phosphatase activity was highest in sole oat. Particulate OM was highest in the 100% oat treatment and declined with decrease in the proportion of oat in the biculture. The 50% oat + 50% vetch treatment had similar POM to the 70% oat +30% vetch in the 4 month old trial and to the 90% oat + 10% vetch in the 28 months old trial in the 0-5 cm depth (P < 0.05). In the 5-20 cm depth, the 70% oat +30% vetch treatment had similar POM to the 90% oat + 10% vetch in the 28 month old trial. The 70% oat+30% vetch had greatest WSC and MBC followed by the 90% oat +10% vetch, with the 50% oat + 50% vetch being similar to 100% vetch and 100% oat (MBC only). The 28 months old trial had greater POM and WSC than the 4 months trial. The findings of this study imply that the use of grazing vetch and fertilization of cover crops only improves soil biological activity, represented by MBC and enzyme activities, after 5 years of maize-cover crop rotations in low input conservation agriculture system. Bicultures, particularly the 70% oat + 30% vetch, work better than their sole crops in improving organic matter fractions, MBC and enzyme activities and that POM, WSC, MBC, enzyme activities are useful early indicators of soil organic matter build-up of CA systems.
- Full Text:
- Date Issued: 2014
Electing high-order modes in solid state laser resonators
- Authors: Iheanetu, Kelachukwu
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: http://hdl.handle.net/10353/995 , vital:26516
- Description: The first chapter considered the fundamental processes of laser operation: photon absorption, spontaneous and stimulated emissions. These processes are considered when designing a laser gain medium. A four-level laser scheme was also illustrated. Then, the basic components and operating principle of a simple laser system was presented using a diode end-pumped Nd:YAG solid state laser resonator. The second chapter considered laser light as light rays propagating in the resonator and extensively discussed the oscillating field in the laser resonators. It examined the characteristics of the fundamental Gaussian mode and the same theory was applied to higher-order modes. Chapter three started with an introduction to beam shaping and proceeded to present a review of some intra-cavity beam shaping techniques, the use of; graded phase mirrors, difractive elements { binary phase elements and spiral phase elements. Also, a brief discussion was given on the concept of conventional holography and digital holography. The phase-only spatial light modulator (SLM) was presented, which by default is used to perform (only) phase modulation of optical fields and how it can be use to perform amplitude modulation also. Finally, a detailed discussion of the digital laser which uses the intracavity SLM as a mode selection element was presented, since it was the technique used in the experiment. The elegance of dynamic on-demand mode selection that required only a change of the grey-scale hologram on the SLM was one quality that was exploited in using the digital laser. The next two chapters presented the experiments and results. The concept of the digital laser was first used in the experiment in chapter four, to assemble a stable diode endpumped Nd:YAG solid state laser resonator. Basically, the cavity was of hemispherical configuration using an intra-cavity SLM (virtual concave mirror) as a back re ector and a at mirror output coupler. A virtual concave mirror was achieve on the SLM by using phase modulation to generate the hologram of a lens, which when displayed on the SLM made it to mimic a concave mirror. Then the next phase was using symmetric Laguerre-Gaussian mode function, of zero azimuthal order to generate digital holograms that correspond to amplitude absorbing concentric rings. These holograms, combined with the hologram that iv mimics a concave mirror were used on the SLM to perform high-order Laguerre-Gaussian modes selection in the cavity. The fifth chapter presented the results of the mode selection and considered the purity of the beam at the output coupler by comparing measured modal properties with the theoretical prediction. The outcome confirmed that the modes were of high purity and quality which further implied that the cavity was indeed selecting single pure high-order modes. The results also demonstrated that forcing the cavity to oscillate at higher-order modes (p = 3) extracted 74% more power from the gain medium compared to the fundamental mode (p = 0), but this extra power is only accessible beyond a critical pump input power of 38.8 W. Laser brightness describes the potential of a laser beam to achieve high intensities while still maintaining a large Rayleigh range. It is a property that is dependent on beam power and its quality factor. To achieve high brightness one needs to generate a beam that extracts maximum power from the gain with good beam quality. Building on the experiments demonstrated in this study, one can make the correct choices of output coupler's re ectivity, the laser gain medium's length and doping concentration and the pump mode overlap for a particular mode to further enhance energy extraction from the cavity, and then using well known extra-cavity techniques to improve the output beams quality factor by transforming the high-order mode back to the fundamental mode. This will electively achieve higher laser brightness.
- Full Text:
- Date Issued: 2014
- Authors: Iheanetu, Kelachukwu
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Physics)
- Identifier: http://hdl.handle.net/10353/995 , vital:26516
- Description: The first chapter considered the fundamental processes of laser operation: photon absorption, spontaneous and stimulated emissions. These processes are considered when designing a laser gain medium. A four-level laser scheme was also illustrated. Then, the basic components and operating principle of a simple laser system was presented using a diode end-pumped Nd:YAG solid state laser resonator. The second chapter considered laser light as light rays propagating in the resonator and extensively discussed the oscillating field in the laser resonators. It examined the characteristics of the fundamental Gaussian mode and the same theory was applied to higher-order modes. Chapter three started with an introduction to beam shaping and proceeded to present a review of some intra-cavity beam shaping techniques, the use of; graded phase mirrors, difractive elements { binary phase elements and spiral phase elements. Also, a brief discussion was given on the concept of conventional holography and digital holography. The phase-only spatial light modulator (SLM) was presented, which by default is used to perform (only) phase modulation of optical fields and how it can be use to perform amplitude modulation also. Finally, a detailed discussion of the digital laser which uses the intracavity SLM as a mode selection element was presented, since it was the technique used in the experiment. The elegance of dynamic on-demand mode selection that required only a change of the grey-scale hologram on the SLM was one quality that was exploited in using the digital laser. The next two chapters presented the experiments and results. The concept of the digital laser was first used in the experiment in chapter four, to assemble a stable diode endpumped Nd:YAG solid state laser resonator. Basically, the cavity was of hemispherical configuration using an intra-cavity SLM (virtual concave mirror) as a back re ector and a at mirror output coupler. A virtual concave mirror was achieve on the SLM by using phase modulation to generate the hologram of a lens, which when displayed on the SLM made it to mimic a concave mirror. Then the next phase was using symmetric Laguerre-Gaussian mode function, of zero azimuthal order to generate digital holograms that correspond to amplitude absorbing concentric rings. These holograms, combined with the hologram that iv mimics a concave mirror were used on the SLM to perform high-order Laguerre-Gaussian modes selection in the cavity. The fifth chapter presented the results of the mode selection and considered the purity of the beam at the output coupler by comparing measured modal properties with the theoretical prediction. The outcome confirmed that the modes were of high purity and quality which further implied that the cavity was indeed selecting single pure high-order modes. The results also demonstrated that forcing the cavity to oscillate at higher-order modes (p = 3) extracted 74% more power from the gain medium compared to the fundamental mode (p = 0), but this extra power is only accessible beyond a critical pump input power of 38.8 W. Laser brightness describes the potential of a laser beam to achieve high intensities while still maintaining a large Rayleigh range. It is a property that is dependent on beam power and its quality factor. To achieve high brightness one needs to generate a beam that extracts maximum power from the gain with good beam quality. Building on the experiments demonstrated in this study, one can make the correct choices of output coupler's re ectivity, the laser gain medium's length and doping concentration and the pump mode overlap for a particular mode to further enhance energy extraction from the cavity, and then using well known extra-cavity techniques to improve the output beams quality factor by transforming the high-order mode back to the fundamental mode. This will electively achieve higher laser brightness.
- Full Text:
- Date Issued: 2014
Enhancement of the usability of SOA services for novice users
- Authors: Yalezo, Sabelo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/822 , vital:26500
- Description: Recently, the automation of service integration has provided a significant advantage in delivering services to novice users. This art of integrating various services is known as Service Composition and its main purpose is to simplify the development process for web applications and facilitates reuse of services. It is one of the paradigms that enables services to end-users (i.e.service provisioning) through the outsourcing of web contents and it requires users to share and reuse services in more collaborative ways. Most service composers are effective at enabling integration of web contents, but they do not enable universal access across different groups of users. This is because, the currently existing content aggregators require complex interactions in order to create web applications (e.g., Web Service Business Process Execution Language (WS-BPEL)) as a result not all users are able to use such web tools. This trend demands changes in the web tools that end-users use to gain and share information, hence this research uses Mashups as a service composition technique to allow novice users to integrate publicly available Service Oriented Architecture (SOA) services, where there is a minimal active web application development. Mashups being the platforms that integrate disparate web Application Programming Interfaces (APIs) to create user defined web applications; presents a great opportunity for service provisioning. However, their usability for novice users remains invalidated since Mashup tools are not easy to use they require basic programming skills which makes the process of designing and creating Mashups difficult. This is because Mashup tools access heterogeneous web contents using public web APIs and the process of integrating them become complex since web APIs are tailored by different vendors. Moreover, the design of Mashup editors is unnecessary complex; as a result, users do not know where to start when creating Mashups. This research address the gap between Mashup tools and usability by the designing and implementing a semantically enriched Mashup tool to discover, annotate and compose APIs to improve the utilization of SOA services by novice users. The researchers conducted an analysis of the already existing Mashup tools to identify challenges and weaknesses experienced by novice Mashup users. The findings from the requirement analysis formulated the system usability requirements that informed the design and implementation of the proposed Mashup tool. The proposed architecture addressed three layers: composition, annotation and discovery. The researchers developed a simple Mashup tool referred to as soa-Services Provisioner (SerPro) that allowed novice users to create web application flexibly. Its usability and effectiveness was validated. The proposed Mashup tool enhanced the usability of SOA services, since data analysis and results showed that it was usable to novice users by scoring a System Usability Scale (SUS) score of 72.08. Furthermore, this research discusses the research limitations and future work for further improvements.
- Full Text:
- Date Issued: 2014
- Authors: Yalezo, Sabelo
- Date: 2014
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: http://hdl.handle.net/10353/822 , vital:26500
- Description: Recently, the automation of service integration has provided a significant advantage in delivering services to novice users. This art of integrating various services is known as Service Composition and its main purpose is to simplify the development process for web applications and facilitates reuse of services. It is one of the paradigms that enables services to end-users (i.e.service provisioning) through the outsourcing of web contents and it requires users to share and reuse services in more collaborative ways. Most service composers are effective at enabling integration of web contents, but they do not enable universal access across different groups of users. This is because, the currently existing content aggregators require complex interactions in order to create web applications (e.g., Web Service Business Process Execution Language (WS-BPEL)) as a result not all users are able to use such web tools. This trend demands changes in the web tools that end-users use to gain and share information, hence this research uses Mashups as a service composition technique to allow novice users to integrate publicly available Service Oriented Architecture (SOA) services, where there is a minimal active web application development. Mashups being the platforms that integrate disparate web Application Programming Interfaces (APIs) to create user defined web applications; presents a great opportunity for service provisioning. However, their usability for novice users remains invalidated since Mashup tools are not easy to use they require basic programming skills which makes the process of designing and creating Mashups difficult. This is because Mashup tools access heterogeneous web contents using public web APIs and the process of integrating them become complex since web APIs are tailored by different vendors. Moreover, the design of Mashup editors is unnecessary complex; as a result, users do not know where to start when creating Mashups. This research address the gap between Mashup tools and usability by the designing and implementing a semantically enriched Mashup tool to discover, annotate and compose APIs to improve the utilization of SOA services by novice users. The researchers conducted an analysis of the already existing Mashup tools to identify challenges and weaknesses experienced by novice Mashup users. The findings from the requirement analysis formulated the system usability requirements that informed the design and implementation of the proposed Mashup tool. The proposed architecture addressed three layers: composition, annotation and discovery. The researchers developed a simple Mashup tool referred to as soa-Services Provisioner (SerPro) that allowed novice users to create web application flexibly. Its usability and effectiveness was validated. The proposed Mashup tool enhanced the usability of SOA services, since data analysis and results showed that it was usable to novice users by scoring a System Usability Scale (SUS) score of 72.08. Furthermore, this research discusses the research limitations and future work for further improvements.
- Full Text:
- Date Issued: 2014
Enterococcus pathotypes as reservoirs of antibiotic resistance determinants in the Kat River and Fort Beaufort abstraction waters
- Authors: Ntloko, Phindiwe
- Date: 2014
- Subjects: Enterococcus , Drug resistance
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11290 , http://hdl.handle.net/10353/d1019821 , Enterococcus , Drug resistance
- Description: In this study, 400 presumptive Enterococcus isolates previously recovered from Kat River and Fort Beaufort Abstraction water dam were subjected to molecular confirmation and pathotyping. Two hundred and seventy-four (68%) of these isolates were confirmed to be enterococci species. Confirmations studies were polymerase chain reaction (PCR) based, using enterococci specific primers targeting the tuf gene. The confirmed enterococci isolates were further differentiated into their pathotypes, the targets of which were: E. faecalis, E. avium, E. hirae, E. casseliflavarus and E. gallinarum using well documented species specific primer sequences. E. faecalis accounted for 20% of the isolates, followed by E. avium (16%), E. hirae (13%), E. casseliflavarus (5%) and E. gallinarum (3%). Furthermore, all the confirmed isolates were analysed for antibiotic susceptibilities using a panel of nine different antibiotics, namely vancomycin, linezolid, ciprofloxacin, ampicillin, gentamicin, chloramphenicol, tetracycline, erythromycin, penicillin, and those that were resistant were assayed for the presence of relevant antibiotic resistance genes. All the 274 isolates were found to harbour vanA resistance gene confirming their phenotypic resistance to the vancomycin. Similarly, 60% (109/180) of the isolates showed phenotypic resistance to erythromycin which was further confirmed by the presence of ermA genes in these isolates. The presence of antibiotic resistant bacteria in surface waters poses a risk to public health.
- Full Text:
- Date Issued: 2014
- Authors: Ntloko, Phindiwe
- Date: 2014
- Subjects: Enterococcus , Drug resistance
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11290 , http://hdl.handle.net/10353/d1019821 , Enterococcus , Drug resistance
- Description: In this study, 400 presumptive Enterococcus isolates previously recovered from Kat River and Fort Beaufort Abstraction water dam were subjected to molecular confirmation and pathotyping. Two hundred and seventy-four (68%) of these isolates were confirmed to be enterococci species. Confirmations studies were polymerase chain reaction (PCR) based, using enterococci specific primers targeting the tuf gene. The confirmed enterococci isolates were further differentiated into their pathotypes, the targets of which were: E. faecalis, E. avium, E. hirae, E. casseliflavarus and E. gallinarum using well documented species specific primer sequences. E. faecalis accounted for 20% of the isolates, followed by E. avium (16%), E. hirae (13%), E. casseliflavarus (5%) and E. gallinarum (3%). Furthermore, all the confirmed isolates were analysed for antibiotic susceptibilities using a panel of nine different antibiotics, namely vancomycin, linezolid, ciprofloxacin, ampicillin, gentamicin, chloramphenicol, tetracycline, erythromycin, penicillin, and those that were resistant were assayed for the presence of relevant antibiotic resistance genes. All the 274 isolates were found to harbour vanA resistance gene confirming their phenotypic resistance to the vancomycin. Similarly, 60% (109/180) of the isolates showed phenotypic resistance to erythromycin which was further confirmed by the presence of ermA genes in these isolates. The presence of antibiotic resistant bacteria in surface waters poses a risk to public health.
- Full Text:
- Date Issued: 2014