Phytochemical analysis and bioactivity of selected South African medicinal plants on clinical isolates of Helicobacter pylori
- Authors: Njume, Collise
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11260 , http://hdl.handle.net/10353/449 , Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Description: Medicinal plants have been used as traditional medicine in the treatment of numerous human diseases for thousands of years in many parts of the world. In the developing world, especially in rural areas, herbal remedies continue to be a primary source of medicine. Scientifically, medicinal plants have proven to be an abundant source of biologically active compounds, many of which have already been formulated into useful therapeutic substances or have provided a basis for the development of new lead molecules for pharmaceuticals. Antibiotic resistance, undesireable side effects and expences associated with the use of combination therapy in the treatment of Helicobacter pylori infections have generated a considerable interest in the study of medicinal plants as potential sources of new drugs against this organism. The high complexicity of bioactive compounds accumulated in plants coupled with their broad antimicrobial activity may make it difficult for pathogenic organisms, including H. pylori to acquire resistance during treatment. This study therefore evaluates the antimicrobial potential of selected South African medicinal plants employed in the treatment of H. pylori-related infections, and the subsequent isolation of the plant active principles. An ethnobotanical survey of plants used in the treatment of H. pylori-related infections was conducted in the study area. Crude extracts of Combretum molle, Sclerocarya birrea, Garcinia kola, Alepidea amatymbica and 2 Strychnos species were screened against 30 clinical strains of H. pylori and 2 standard control strains (NCTC 11638 and ATCC 43526). In the preliminary stages of this study, ethyl acetate, acetone, ethanol, methanol and water extracts of the plants were tested against H. pylori by agar well diffusion and micro broth dilution methods. The plant crude extracts that exhibited anti-H. pylori activity with a iv percentage susceptibility of 50 percent and above were considered for the rate of kill assays and the most active crude extracts selected for bio-assay guided isolation of the active ingredient. Preliminary fractionation of the crude extract was achieved by thin layer chromatography (TLC) using different solvent combinations; hexane/diethylether (HDE), ethyl acetate/methanol/water (EMW) and chloroform/ethyl acetate/formic acid (CEF) in order to determine the most suitable combination for column chromatography (CC) and subsequent testing by indirect bioautography. The extract was then fractionated in a silica gel column using previously determined solvent combinations as eluent. Active fractions obtained from column chromatography separations were further fractionated and the compounds identified by gas chromatography/mass spectrometry (GC/MS) analysis. All the plants exhibited antimicrobial activity against H. pylori with zone of inhibition diameters ranging from 0 - 38 mm and minimum inhibitory concentration (MIC) values ranging from 0.06 - 5.0 mg/mL. The most active plant extracts were the acetone extract of C. molle with a percentage susceptibility of 87.1 percent, acetone and aqueous extracts of S. birrea (71 percent each) and the ethanolic extracts of G. kola (53.3 percent). Except for the aqueous extract, these extracts also exhibited a strong bactericidal activity against H. pylori at different concentrations. TLC analysis revealed the presence of 9 components in the acetone extract of S. birrea with the EMW solvent system as opposed to 5 and 8 with HDE and CEF respectively. Bioassay-guided isolation led to the identification of 52 compounds from the acetone extract of S. birrea with n-octacosane being the most abundant (41.68 percent). This was followed by pyrrolidine (38.91 percent), terpinen-4-ol (38.3 percent), n-eicosane (24.98 percent), cyclopentane (16.76 percent), n-triacontane (16.28 percent), aromadendrene (13.63 percent) and α-gujunene (8.77 percent). Terpinen-4-ol and pyrrolidine demonstrated strong antimicrobial activity against H. pylori at all concentrations tested. These results may serve as preliminary scientific validation of the ethnomedicinal uses of the above mentioned plants in the treatment of H. pylori-related infections in South Africa. Terpinen-4-ol and pyrrolidine could be considered for further evaluation as therapeutic or prophylactic agents in the treatment of H. pylori-related infections. However, further investigations would be necessary to determine their toxicological properties, in-vivo potencies and mechanism of action against H.pylori
- Full Text:
- Date Issued: 2011
- Authors: Njume, Collise
- Date: 2011
- Subjects: Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Language: English
- Type: Thesis , Doctoral , PhD (Microbiology)
- Identifier: vital:11260 , http://hdl.handle.net/10353/449 , Helicobacter pylori , Medicinal plants -- Biotechnology , Traditional medicine -- South Africa -- Eastern Cape , Antibiotics , Drug resistance in microorganisms , Extracts , Helicobacter pylori infections
- Description: Medicinal plants have been used as traditional medicine in the treatment of numerous human diseases for thousands of years in many parts of the world. In the developing world, especially in rural areas, herbal remedies continue to be a primary source of medicine. Scientifically, medicinal plants have proven to be an abundant source of biologically active compounds, many of which have already been formulated into useful therapeutic substances or have provided a basis for the development of new lead molecules for pharmaceuticals. Antibiotic resistance, undesireable side effects and expences associated with the use of combination therapy in the treatment of Helicobacter pylori infections have generated a considerable interest in the study of medicinal plants as potential sources of new drugs against this organism. The high complexicity of bioactive compounds accumulated in plants coupled with their broad antimicrobial activity may make it difficult for pathogenic organisms, including H. pylori to acquire resistance during treatment. This study therefore evaluates the antimicrobial potential of selected South African medicinal plants employed in the treatment of H. pylori-related infections, and the subsequent isolation of the plant active principles. An ethnobotanical survey of plants used in the treatment of H. pylori-related infections was conducted in the study area. Crude extracts of Combretum molle, Sclerocarya birrea, Garcinia kola, Alepidea amatymbica and 2 Strychnos species were screened against 30 clinical strains of H. pylori and 2 standard control strains (NCTC 11638 and ATCC 43526). In the preliminary stages of this study, ethyl acetate, acetone, ethanol, methanol and water extracts of the plants were tested against H. pylori by agar well diffusion and micro broth dilution methods. The plant crude extracts that exhibited anti-H. pylori activity with a iv percentage susceptibility of 50 percent and above were considered for the rate of kill assays and the most active crude extracts selected for bio-assay guided isolation of the active ingredient. Preliminary fractionation of the crude extract was achieved by thin layer chromatography (TLC) using different solvent combinations; hexane/diethylether (HDE), ethyl acetate/methanol/water (EMW) and chloroform/ethyl acetate/formic acid (CEF) in order to determine the most suitable combination for column chromatography (CC) and subsequent testing by indirect bioautography. The extract was then fractionated in a silica gel column using previously determined solvent combinations as eluent. Active fractions obtained from column chromatography separations were further fractionated and the compounds identified by gas chromatography/mass spectrometry (GC/MS) analysis. All the plants exhibited antimicrobial activity against H. pylori with zone of inhibition diameters ranging from 0 - 38 mm and minimum inhibitory concentration (MIC) values ranging from 0.06 - 5.0 mg/mL. The most active plant extracts were the acetone extract of C. molle with a percentage susceptibility of 87.1 percent, acetone and aqueous extracts of S. birrea (71 percent each) and the ethanolic extracts of G. kola (53.3 percent). Except for the aqueous extract, these extracts also exhibited a strong bactericidal activity against H. pylori at different concentrations. TLC analysis revealed the presence of 9 components in the acetone extract of S. birrea with the EMW solvent system as opposed to 5 and 8 with HDE and CEF respectively. Bioassay-guided isolation led to the identification of 52 compounds from the acetone extract of S. birrea with n-octacosane being the most abundant (41.68 percent). This was followed by pyrrolidine (38.91 percent), terpinen-4-ol (38.3 percent), n-eicosane (24.98 percent), cyclopentane (16.76 percent), n-triacontane (16.28 percent), aromadendrene (13.63 percent) and α-gujunene (8.77 percent). Terpinen-4-ol and pyrrolidine demonstrated strong antimicrobial activity against H. pylori at all concentrations tested. These results may serve as preliminary scientific validation of the ethnomedicinal uses of the above mentioned plants in the treatment of H. pylori-related infections in South Africa. Terpinen-4-ol and pyrrolidine could be considered for further evaluation as therapeutic or prophylactic agents in the treatment of H. pylori-related infections. However, further investigations would be necessary to determine their toxicological properties, in-vivo potencies and mechanism of action against H.pylori
- Full Text:
- Date Issued: 2011
Crime, violence and apartheid in selected works of Richard Wright and Athol Fugard: a study
- Authors: Makombe, Rodwell
- Date: 2011
- Subjects: Apartheid in literature , Politics and literature -- South Africa , Race discrimination -- South Africa , Crime -- South Africa , Violence -- South Africa
- Language: English
- Type: Thesis , Doctoral , DLitt et Phil (English)
- Identifier: vital:11888 , http://hdl.handle.net/10353/525 , Apartheid in literature , Politics and literature -- South Africa , Race discrimination -- South Africa , Crime -- South Africa , Violence -- South Africa
- Description: Different forms of racial segregation have been practiced in different countries the world over. However, the nature of South Africa‟s apartheid system, as it was practiced from 1948 until the dawn of the democratic dispensation in 1994, has been a subject of debate in South Africa and even beyond. Apartheid was a policy that was designed by the then ruling Nationalist Party for purposes of dividing and stratifying South Africa along racial lines - whites, blacks, coloureds and Asians. It thus promoted racial segregation and/or unequal stratification of society. In South Africa‟s hierarchy of apartheid, blacks, who constituted the majority of the population, were ironically the most destitute and segregated. Some historians believe that South Africa‟s racial policy was designed against the backdrop of Jim Crow, a similar system of racial discrimination which was instituted in the American South late in the 1890s through the 20th century. Jim Crow and apartheid are, in this study, considered as sides of the same coin; hence for the sake of convenience, the word apartheid is used to subsume Jim Crow. Although South Africa‟s apartheid system was influenced by different ideologies, for example German missiology as applied by the Dutch Reformed Church, historian Hermann Giliomee (2003: 373) insists that „the segregationist practice of the American South was particularly influential.‟ Given the ideological relationship between apartheid and Jim Crow, the present study investigates the interplay of compatibility between apartheid/Jim Crow and crime and violence as reflected in selected works of Richard Wright (African American novelist) and Athol Fugard (South African playwright). The aim of the study is firstly, to examine the works in order to analyse them as responses to apartheid and by extension colonial domination and secondly to investigate crime and violence. The three criminological theories selected for this study are strain theory (by Robert Merton), subculture theory (Edwin Sutherland) and labelling theory (Howard Becker). While criminological theory provides an empirical dimension to the study, postcolonial theory situates the study within a specified space, which is the postcolonial context. The postcolonial is, however understood, not as a demarcated historical space, but as a continuum, from the dawn of colonization to the unforeseeable future. Three postcolonial theorists have been identified for the purposes of this study. These are: Frantz Fanon, Homi Bhabha and Bill Ashcroft. Fanon‟s psychoanalysis of the colonized, Homi Bhabha‟s Third Space and hybridity as well as Ashcroft‟s postcolonial transformation are key concepts in understanding the different ways in which the colonized deal with the consequences of colonization. It has been suggested particularly in Edward Said‟s Orientalism (1978) that the discourse of orientalism creates the Oriental, as if Orientals were a passive object of the colonial adventure. This study uses Bhabha‟s and Ashcroft‟s theory of colonial discourse to argue that the colonized are not only objects of the colonial enterprise but also active participants in the process of opening survival spaces for self-realization. The various criminal activities that the colonized engage in (as represented in the selected works of Richard Wright and Athol Fugard) are in this study viewed as ways of inscribing their subjectivity within an exclusive colonial system.
- Full Text:
- Date Issued: 2011
- Authors: Makombe, Rodwell
- Date: 2011
- Subjects: Apartheid in literature , Politics and literature -- South Africa , Race discrimination -- South Africa , Crime -- South Africa , Violence -- South Africa
- Language: English
- Type: Thesis , Doctoral , DLitt et Phil (English)
- Identifier: vital:11888 , http://hdl.handle.net/10353/525 , Apartheid in literature , Politics and literature -- South Africa , Race discrimination -- South Africa , Crime -- South Africa , Violence -- South Africa
- Description: Different forms of racial segregation have been practiced in different countries the world over. However, the nature of South Africa‟s apartheid system, as it was practiced from 1948 until the dawn of the democratic dispensation in 1994, has been a subject of debate in South Africa and even beyond. Apartheid was a policy that was designed by the then ruling Nationalist Party for purposes of dividing and stratifying South Africa along racial lines - whites, blacks, coloureds and Asians. It thus promoted racial segregation and/or unequal stratification of society. In South Africa‟s hierarchy of apartheid, blacks, who constituted the majority of the population, were ironically the most destitute and segregated. Some historians believe that South Africa‟s racial policy was designed against the backdrop of Jim Crow, a similar system of racial discrimination which was instituted in the American South late in the 1890s through the 20th century. Jim Crow and apartheid are, in this study, considered as sides of the same coin; hence for the sake of convenience, the word apartheid is used to subsume Jim Crow. Although South Africa‟s apartheid system was influenced by different ideologies, for example German missiology as applied by the Dutch Reformed Church, historian Hermann Giliomee (2003: 373) insists that „the segregationist practice of the American South was particularly influential.‟ Given the ideological relationship between apartheid and Jim Crow, the present study investigates the interplay of compatibility between apartheid/Jim Crow and crime and violence as reflected in selected works of Richard Wright (African American novelist) and Athol Fugard (South African playwright). The aim of the study is firstly, to examine the works in order to analyse them as responses to apartheid and by extension colonial domination and secondly to investigate crime and violence. The three criminological theories selected for this study are strain theory (by Robert Merton), subculture theory (Edwin Sutherland) and labelling theory (Howard Becker). While criminological theory provides an empirical dimension to the study, postcolonial theory situates the study within a specified space, which is the postcolonial context. The postcolonial is, however understood, not as a demarcated historical space, but as a continuum, from the dawn of colonization to the unforeseeable future. Three postcolonial theorists have been identified for the purposes of this study. These are: Frantz Fanon, Homi Bhabha and Bill Ashcroft. Fanon‟s psychoanalysis of the colonized, Homi Bhabha‟s Third Space and hybridity as well as Ashcroft‟s postcolonial transformation are key concepts in understanding the different ways in which the colonized deal with the consequences of colonization. It has been suggested particularly in Edward Said‟s Orientalism (1978) that the discourse of orientalism creates the Oriental, as if Orientals were a passive object of the colonial adventure. This study uses Bhabha‟s and Ashcroft‟s theory of colonial discourse to argue that the colonized are not only objects of the colonial enterprise but also active participants in the process of opening survival spaces for self-realization. The various criminal activities that the colonized engage in (as represented in the selected works of Richard Wright and Athol Fugard) are in this study viewed as ways of inscribing their subjectivity within an exclusive colonial system.
- Full Text:
- Date Issued: 2011
The business sustainability of an automotive refinish paint distributor
- Authors: Msuthwana, Vusumzi M
- Date: 2011
- Subjects: Business enterprises -- Development , Business enterprises -- Marketing , Business -- Sustainability
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9371 , http://hdl.handle.net/10948/d1012376 , Business enterprises -- Development , Business enterprises -- Marketing , Business -- Sustainability
- Description: From a broad overview of business management literature, the proposition emerged that strategic conditions within an organisation can translate into sustainable business development outcomes. However, in the rapidly evolving business environment, the quest to grow or sustain competitive advantage demands that business practices become more proactive, creative and innovative. Globalisation and technological advances drive the need for innovation within a business context and the resultant rapid pace of change demands that businesses adopt a customer-focused entrepreneurial orientation to accommodate this need for innovation. This study investigated whether the principles of marketing, business management tools and management of the customer-base could be incorporated as key drivers to develop innovative and creative tactics that could serve as viable solutions to sustain business development strategies of automotive refinish paint distributors. An initial step in this research comprised a theoretical overview of the internal business environment as a system of the enterprise that aims to provide an in-depth understanding of the organisation, which could be applied to support strategic business goals and objectives. The literature review further entailed an investigation and explorations regarding best practices that automotive refinish paint distributors could follow in order to identify, focus on and develop their source of competitive advantage, sustainability and profitability. From the literature review, a methodological framework was developed that could be applied to specific success indicators, moulded to produce distinctive competencies in the automotive refinish paint industry; defining a significant foundation from which the objectives of this study could be researched. The study adopted the qualitative research approach and focused on a single case of a refinish paint distributor. The reason for selecting the case study method is that an entire organisation could be investigated in depth with particular attention to detail. A detailed questionnaire was drawn up in order to conduct face-to-face interviews with selected respondents, based on the profound expertise of the selected personnel. This was done to enable the researcher to assess the prevalent elements of business sustainability applied by the automotive refinish distributor to enhance their competitive advantage. The design of the empirical element of this study, aimed at providing a blueprint that would enable the researcher to structure the research problem in such a way that the outcome of the study would be valid, objective and reliable. Due to the qualitative nature of this study, the results are interpreted through inductive reasoning, observations, projective and participatory approaches all of which are integrated into a comprehensive model indicating key drivers to promote, improve and facilitate the business sustainability of the automotive refinish paint distributor. A range of recommendations and managerial implications extracted from the results of the empirical study are presented in the final chapter.
- Full Text:
- Date Issued: 2011
- Authors: Msuthwana, Vusumzi M
- Date: 2011
- Subjects: Business enterprises -- Development , Business enterprises -- Marketing , Business -- Sustainability
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9371 , http://hdl.handle.net/10948/d1012376 , Business enterprises -- Development , Business enterprises -- Marketing , Business -- Sustainability
- Description: From a broad overview of business management literature, the proposition emerged that strategic conditions within an organisation can translate into sustainable business development outcomes. However, in the rapidly evolving business environment, the quest to grow or sustain competitive advantage demands that business practices become more proactive, creative and innovative. Globalisation and technological advances drive the need for innovation within a business context and the resultant rapid pace of change demands that businesses adopt a customer-focused entrepreneurial orientation to accommodate this need for innovation. This study investigated whether the principles of marketing, business management tools and management of the customer-base could be incorporated as key drivers to develop innovative and creative tactics that could serve as viable solutions to sustain business development strategies of automotive refinish paint distributors. An initial step in this research comprised a theoretical overview of the internal business environment as a system of the enterprise that aims to provide an in-depth understanding of the organisation, which could be applied to support strategic business goals and objectives. The literature review further entailed an investigation and explorations regarding best practices that automotive refinish paint distributors could follow in order to identify, focus on and develop their source of competitive advantage, sustainability and profitability. From the literature review, a methodological framework was developed that could be applied to specific success indicators, moulded to produce distinctive competencies in the automotive refinish paint industry; defining a significant foundation from which the objectives of this study could be researched. The study adopted the qualitative research approach and focused on a single case of a refinish paint distributor. The reason for selecting the case study method is that an entire organisation could be investigated in depth with particular attention to detail. A detailed questionnaire was drawn up in order to conduct face-to-face interviews with selected respondents, based on the profound expertise of the selected personnel. This was done to enable the researcher to assess the prevalent elements of business sustainability applied by the automotive refinish distributor to enhance their competitive advantage. The design of the empirical element of this study, aimed at providing a blueprint that would enable the researcher to structure the research problem in such a way that the outcome of the study would be valid, objective and reliable. Due to the qualitative nature of this study, the results are interpreted through inductive reasoning, observations, projective and participatory approaches all of which are integrated into a comprehensive model indicating key drivers to promote, improve and facilitate the business sustainability of the automotive refinish paint distributor. A range of recommendations and managerial implications extracted from the results of the empirical study are presented in the final chapter.
- Full Text:
- Date Issued: 2011
Dynamics of macrophytes in the East Kleinemonde, a small temporarily open/closed South Afrcan Estuary
- Authors: Riddin, Taryn
- Date: 2011
- Subjects: Estuaries -- South Africa -- East Kleinemonde
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10605 , http://hdl.handle.net/10948/1529 , Estuaries -- South Africa -- East Kleinemonde
- Description: The East Kleinemonde Estuary is one of 175 temporarily open/closed estuaries (TOCEs) that represent 70 percent of estuaries in South Africa. TOCEs are small (mostly less than 100 ha), shallow estuaries (average depth < 2 m) that respond quickly to freshwater inflow events. Their connection to the sea can be highly variable resulting in considerable changes in abiotic and biotic conditions. Mouth status depends on a balance between freshwater inflow and marine influence, which in turn affects ambient abiotic conditions. The objective of the study was to identify the abiotic variables which influence macrophyte growth and habitat availability. It was hypothesised that water level and salinity were the two main drivers of macrophyte change and macrophyte habitat would respond very rapidly, in less than a month, when habitat was available. Macrophyte habitats would also have high sediment seed reserves to ensure persistence under highly variable abiotic conditions. Macrophyte cover was monitored monthly in the East Kleinemonde Estuary along three permanent transects. The dominant habitats were submerged macrophytes, intertidal salt marsh, supratidal salt marsh, reeds and sedges. The following abiotic variables; water level, water column salinity, water temperature, Secchi depth, air temperature and rainfall were also measured between March 2006 and January 2010. Time-lag responses of the macrophytes to water level and salinity changes up to four months prior to the sampling session were also assessed. The analysis of a one year dataset highlighted only water level as a driver of change in macrophyte cover, whereas the five year dataset identified salinity as an additional important abiotic driver. This is because during September 2008 to January 2010 a series of large marine overwash events maintained high salinity (> 30 ppt) and high water level (> 1.6 m amsl) in the estuary. Water level increased by up to 0.33 m due to large volumetric changes and salinity was significantly higher in the 16 month closed euhaline phase after the breach (31 ± 0.9 ppt) compared to 21.9 ± 0.9 ppt in the closed polyhaline phase before the September 2008 breach. This increase in salinity significantly reduced the cover of the submerged macrophytes Ruppia cirrhosa and Chara vulgaris. They were replaced by macroalgae during this high salinity phase. The cover of supratidal salt marsh and reed habitats was also significantly reduced during the high water level phase, which in turn would lead to the potential for bank destabilisation and erosion. Based on the average elevation above sea level position of the macrophytes in the East Kleinemonde iv Estuary, a threshold water level was identified as 1.55 amsl. This was taken to be the height above sea level at which there was a maximum cover change for each macrophyte habitat. Above this water level emergent macrophyte habitat would mainly be inundated. This, together with 30 ppt salinity, was identified as the two thresholds for macrophyte change in the East Kleinemonde Estuary. From these thresholds and the 5 year dataset four biotic states were identified as State A: open and tidal, State B: closed with a water level below 1.55 m amsl and salinity between 18 to 30 ppt, State C: closed and water level above 1.55 m amsl and salinity between 18 to 30 ppt and State D: closed and water level above 1.55 m amsl and salinity above 30 ppt. Intertidal salt marsh, reeds and sedges were dominant during the open phase. Submerged macrophytes were dominant during the closed polyhaline state and macroalgae during the closed euhaline state. The high variability of abiotic factors common in TOCEs and the response of macrophyte habitat indicated that macrophytes were resilient to changing states provided they were of relatively short (< 3 months) duration. Macrophytes in the East Kleinemonde Estuary were found to have fast growth rates and large seed reserves in the sediment. The seed banks in the East Kleinemonde, as well as the adjacent temporarily open/closed West Kleinemonde Estuary were quantified for the first time in a South African estuary. The averaged data from both estuaries showed that Charophyte öospores represented almost 72 percent of the sexual propagules in the sediment with a mean öospore density of 31 306 ± 2 293 m-2. This was despite the Charophytes being sparsely located and only representing a maximum of 32.5 percent cover in the above ground vegetation. Historically there must have been stands of Charophytes in the East Kleinemonde Estuary, such that öospores could accumulate to such high density found in this study. The second highest seed density was for the intertidal salt marsh plant Sarcocornia tegetaria (18 percent) (7 929 ± 688 seed m-2), followed by the submerged angiosperm Ruppia cirrhosa (7 percent) (2 852 ± 327 seeds m-2). Although seed density did not differ significantly with sediment depth, seeds still occurred at 20 cm below the surface of the sediment providing a regeneration source in the event of sediment scouring during a flood event. Germination studies in the greenhouse showed that most seeds were viable and Sarcocornia tegetaria began to germinate after 3 days to a maximum of 82 percent after 91 days. Submerged species only germinated after 18 days with a low maximum germination of between 11 and 15 percent. This study has made an original contribution to the field of knowledge on macrophyte responses in a small TOCE as it showed that macrophyte habitats in the East Kleinemonde Estuary have a high natural variability in cover over time, they respond quickly after a disturbance event such as a mouth breach and there are large sediment seed reserves that remain viable from 2 to more than 5 years. This ensures habitat persistence even under unfavourable conditions, such as prolonged periods of mouth closure with high water level and flooding which causes loss of salt marsh species. Given this natural variability it is necessary to predict responses both spatially and temporally in order to manage and maintain ecological functioning in TOCEs. This study identified dominant macrophyte habitat for different abiotic states through the use of water level and salinity thresholds. In the determination of the freshwater requirements of any South African estuary freshwater inflow rates are provided for each estuary's past, present and possible future freshwater inflow scenarios. These flow data are generated by hydrological models and simulated monthly inflow volumes for a period of about 72 years are provided. For the East Kleinemonde freshwater requirement study for any year in that 70-odd year period, the number of high flow and low flow mouth breaches were predicted, as well as the closed state periods. The threshold water level of 1.55 m amsl was also used to filter past, present and future inflow monthly volumes to determine the frequency of the four abiotic states identified in this study. It was based on a water level/water volume equation calculation from a digital elevation model. Results showed that the total closed period in the present state was 83 percent, made up of 48 percent of the time in a polyhaline state (State C) and 35 percent in a euahaline state (State D). A second method was used to quantify available spatial habitat under different water level scenarios. A spatial model was written in Model Builder, an application in ArcGIS that allowed a series of processes to be built. A habitat map was overlaid with a bathymetric map and by selecting water level, available habitat areas were determined and empirical equations of water level versus available habitat were produced. These equations were then used to calculate the available habitat areas for monthly water level conditions from the freshwater requirement study for the past, present and two future inflow scenarios. Using both the threshold water level method and the spatial availability model method it was possible to assess the effect of the two future inflow scenarios on macrophyte habitat vi response. Scenario 1 had a 16 percent reduction in mean annual runoff (MAR) generating low flows for 88.6 percent of the time and a 3.5 percent reduction in flood events. In Scenario 2 there would be a 12 percent reduction in MAR with low flows occurring for 87.5 percent of the year, a 5.3 percent reduction in floods and an 11.5 percent reduction in the open mouth state. The model showed that Scenario 1 would have the highest submerged macrophyte area (12.56 ha versus 12.48 ha in Scenario 2), whereas Scenario 2 produced the largest mudflat and intertidal salt marsh area (7.11 ha versus 7.34 ha) due to lower water level in conjunction with the bathymetry of the estuary. A reduction in freshwater inflow to TOCEs either due to anthropogenic influences or natural precipitation cycles is one of the main threats to the optimum functioning of these estuaries. The results from this study and the two methods of assessing the effect of freshwater inflow scenarios on macrophytes in TOCEs can be integrated into the current freshwater inflow assessment methodology in South Africa, as well as adding to our understanding of the ecological functioning of these small, highly variable estuaries. The methods provide a quick assessment of macrophyte habitat associated with abiotic states under past, present and future inflow scenarios. All that is required to predict macrophyte habitat for different freshwater inflow scenarios (present, past and future) is a habitat map, a bathymetric map and the elevation range of macrophytes in the TOCE being assessed. This, together with the knowledge of response rates, provides invaluable information for the management of TOCEs to maintain their ecological functioning under altered freshwater inflow regimes.
- Full Text:
- Date Issued: 2011
- Authors: Riddin, Taryn
- Date: 2011
- Subjects: Estuaries -- South Africa -- East Kleinemonde
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10605 , http://hdl.handle.net/10948/1529 , Estuaries -- South Africa -- East Kleinemonde
- Description: The East Kleinemonde Estuary is one of 175 temporarily open/closed estuaries (TOCEs) that represent 70 percent of estuaries in South Africa. TOCEs are small (mostly less than 100 ha), shallow estuaries (average depth < 2 m) that respond quickly to freshwater inflow events. Their connection to the sea can be highly variable resulting in considerable changes in abiotic and biotic conditions. Mouth status depends on a balance between freshwater inflow and marine influence, which in turn affects ambient abiotic conditions. The objective of the study was to identify the abiotic variables which influence macrophyte growth and habitat availability. It was hypothesised that water level and salinity were the two main drivers of macrophyte change and macrophyte habitat would respond very rapidly, in less than a month, when habitat was available. Macrophyte habitats would also have high sediment seed reserves to ensure persistence under highly variable abiotic conditions. Macrophyte cover was monitored monthly in the East Kleinemonde Estuary along three permanent transects. The dominant habitats were submerged macrophytes, intertidal salt marsh, supratidal salt marsh, reeds and sedges. The following abiotic variables; water level, water column salinity, water temperature, Secchi depth, air temperature and rainfall were also measured between March 2006 and January 2010. Time-lag responses of the macrophytes to water level and salinity changes up to four months prior to the sampling session were also assessed. The analysis of a one year dataset highlighted only water level as a driver of change in macrophyte cover, whereas the five year dataset identified salinity as an additional important abiotic driver. This is because during September 2008 to January 2010 a series of large marine overwash events maintained high salinity (> 30 ppt) and high water level (> 1.6 m amsl) in the estuary. Water level increased by up to 0.33 m due to large volumetric changes and salinity was significantly higher in the 16 month closed euhaline phase after the breach (31 ± 0.9 ppt) compared to 21.9 ± 0.9 ppt in the closed polyhaline phase before the September 2008 breach. This increase in salinity significantly reduced the cover of the submerged macrophytes Ruppia cirrhosa and Chara vulgaris. They were replaced by macroalgae during this high salinity phase. The cover of supratidal salt marsh and reed habitats was also significantly reduced during the high water level phase, which in turn would lead to the potential for bank destabilisation and erosion. Based on the average elevation above sea level position of the macrophytes in the East Kleinemonde iv Estuary, a threshold water level was identified as 1.55 amsl. This was taken to be the height above sea level at which there was a maximum cover change for each macrophyte habitat. Above this water level emergent macrophyte habitat would mainly be inundated. This, together with 30 ppt salinity, was identified as the two thresholds for macrophyte change in the East Kleinemonde Estuary. From these thresholds and the 5 year dataset four biotic states were identified as State A: open and tidal, State B: closed with a water level below 1.55 m amsl and salinity between 18 to 30 ppt, State C: closed and water level above 1.55 m amsl and salinity between 18 to 30 ppt and State D: closed and water level above 1.55 m amsl and salinity above 30 ppt. Intertidal salt marsh, reeds and sedges were dominant during the open phase. Submerged macrophytes were dominant during the closed polyhaline state and macroalgae during the closed euhaline state. The high variability of abiotic factors common in TOCEs and the response of macrophyte habitat indicated that macrophytes were resilient to changing states provided they were of relatively short (< 3 months) duration. Macrophytes in the East Kleinemonde Estuary were found to have fast growth rates and large seed reserves in the sediment. The seed banks in the East Kleinemonde, as well as the adjacent temporarily open/closed West Kleinemonde Estuary were quantified for the first time in a South African estuary. The averaged data from both estuaries showed that Charophyte öospores represented almost 72 percent of the sexual propagules in the sediment with a mean öospore density of 31 306 ± 2 293 m-2. This was despite the Charophytes being sparsely located and only representing a maximum of 32.5 percent cover in the above ground vegetation. Historically there must have been stands of Charophytes in the East Kleinemonde Estuary, such that öospores could accumulate to such high density found in this study. The second highest seed density was for the intertidal salt marsh plant Sarcocornia tegetaria (18 percent) (7 929 ± 688 seed m-2), followed by the submerged angiosperm Ruppia cirrhosa (7 percent) (2 852 ± 327 seeds m-2). Although seed density did not differ significantly with sediment depth, seeds still occurred at 20 cm below the surface of the sediment providing a regeneration source in the event of sediment scouring during a flood event. Germination studies in the greenhouse showed that most seeds were viable and Sarcocornia tegetaria began to germinate after 3 days to a maximum of 82 percent after 91 days. Submerged species only germinated after 18 days with a low maximum germination of between 11 and 15 percent. This study has made an original contribution to the field of knowledge on macrophyte responses in a small TOCE as it showed that macrophyte habitats in the East Kleinemonde Estuary have a high natural variability in cover over time, they respond quickly after a disturbance event such as a mouth breach and there are large sediment seed reserves that remain viable from 2 to more than 5 years. This ensures habitat persistence even under unfavourable conditions, such as prolonged periods of mouth closure with high water level and flooding which causes loss of salt marsh species. Given this natural variability it is necessary to predict responses both spatially and temporally in order to manage and maintain ecological functioning in TOCEs. This study identified dominant macrophyte habitat for different abiotic states through the use of water level and salinity thresholds. In the determination of the freshwater requirements of any South African estuary freshwater inflow rates are provided for each estuary's past, present and possible future freshwater inflow scenarios. These flow data are generated by hydrological models and simulated monthly inflow volumes for a period of about 72 years are provided. For the East Kleinemonde freshwater requirement study for any year in that 70-odd year period, the number of high flow and low flow mouth breaches were predicted, as well as the closed state periods. The threshold water level of 1.55 m amsl was also used to filter past, present and future inflow monthly volumes to determine the frequency of the four abiotic states identified in this study. It was based on a water level/water volume equation calculation from a digital elevation model. Results showed that the total closed period in the present state was 83 percent, made up of 48 percent of the time in a polyhaline state (State C) and 35 percent in a euahaline state (State D). A second method was used to quantify available spatial habitat under different water level scenarios. A spatial model was written in Model Builder, an application in ArcGIS that allowed a series of processes to be built. A habitat map was overlaid with a bathymetric map and by selecting water level, available habitat areas were determined and empirical equations of water level versus available habitat were produced. These equations were then used to calculate the available habitat areas for monthly water level conditions from the freshwater requirement study for the past, present and two future inflow scenarios. Using both the threshold water level method and the spatial availability model method it was possible to assess the effect of the two future inflow scenarios on macrophyte habitat vi response. Scenario 1 had a 16 percent reduction in mean annual runoff (MAR) generating low flows for 88.6 percent of the time and a 3.5 percent reduction in flood events. In Scenario 2 there would be a 12 percent reduction in MAR with low flows occurring for 87.5 percent of the year, a 5.3 percent reduction in floods and an 11.5 percent reduction in the open mouth state. The model showed that Scenario 1 would have the highest submerged macrophyte area (12.56 ha versus 12.48 ha in Scenario 2), whereas Scenario 2 produced the largest mudflat and intertidal salt marsh area (7.11 ha versus 7.34 ha) due to lower water level in conjunction with the bathymetry of the estuary. A reduction in freshwater inflow to TOCEs either due to anthropogenic influences or natural precipitation cycles is one of the main threats to the optimum functioning of these estuaries. The results from this study and the two methods of assessing the effect of freshwater inflow scenarios on macrophytes in TOCEs can be integrated into the current freshwater inflow assessment methodology in South Africa, as well as adding to our understanding of the ecological functioning of these small, highly variable estuaries. The methods provide a quick assessment of macrophyte habitat associated with abiotic states under past, present and future inflow scenarios. All that is required to predict macrophyte habitat for different freshwater inflow scenarios (present, past and future) is a habitat map, a bathymetric map and the elevation range of macrophytes in the TOCE being assessed. This, together with the knowledge of response rates, provides invaluable information for the management of TOCEs to maintain their ecological functioning under altered freshwater inflow regimes.
- Full Text:
- Date Issued: 2011
An analysis of sources and predictability of geomagnetic storms
- Authors: Uwamahoro, Jean
- Date: 2011
- Subjects: Ionospheric storms Solar flares Interplanetary magnetic fields Magnetospheric substorms Coronal mass ejections Space environment Neural networks (Computer science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5451 , http://hdl.handle.net/10962/d1005236
- Description: Solar transient eruptions are the main cause of interplanetary-magnetospheric disturbances leading to the phenomena known as geomagnetic storms. Eruptive solar events such as coronal mass ejections (CMEs) are currently considered the main cause of geomagnetic storms (GMS). GMS are strong perturbations of the Earth’s magnetic field that can affect space-borne and ground-based technological systems. The solar-terrestrial impact on modern technological systems is commonly known as Space Weather. Part of the research study described in this thesis was to investigate and establish a relationship between GMS (periods with Dst ≤ −50 nT) and their associated solar and interplanetary (IP) properties during solar cycle (SC) 23. Solar and IP geoeffective properties associated with or without CMEs were investigated and used to qualitatively characterise both intense and moderate storms. The results of this analysis specifically provide an estimate of the main sources of GMS during an average 11-year solar activity period. This study indicates that during SC 23, the majority of intense GMS (83%) were associated with CMEs, while the non-associated CME storms were dominant among moderate storms. GMS phenomena are the result of a complex and non-linear chaotic system involving the Sun, the IP medium, the magnetosphere and ionosphere, which make the prediction of these phenomena challenging. This thesis also explored the predictability of both the occurrence and strength of GMS. Due to their nonlinear driving mechanisms, the prediction of GMS was attempted by the use of neural network (NN) techniques, known for their non-linear modelling capabilities. To predict the occurrence of storms, a combination of solar and IP parameters were used as inputs in the NN model that proved to predict the occurrence of GMS with a probability of 87%. Using the solar wind (SW) and IP magnetic field (IMF) parameters, a separate NN-based model was developed to predict the storm-time strength as measured by the global Dst and ap geomagnetic indices, as well as by the locally measured K-index. The performance of the models was tested on data sets which were not part of the NN training process. The results obtained indicate that NN models provide a reliable alternative method for empirically predicting the occurrence and strength of GMS on the basis of solar and IP parameters. The demonstrated ability to predict the geoeffectiveness of solar and IP transient events is a key step in the goal towards improving space weather modelling and prediction.
- Full Text:
- Date Issued: 2011
- Authors: Uwamahoro, Jean
- Date: 2011
- Subjects: Ionospheric storms Solar flares Interplanetary magnetic fields Magnetospheric substorms Coronal mass ejections Space environment Neural networks (Computer science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5451 , http://hdl.handle.net/10962/d1005236
- Description: Solar transient eruptions are the main cause of interplanetary-magnetospheric disturbances leading to the phenomena known as geomagnetic storms. Eruptive solar events such as coronal mass ejections (CMEs) are currently considered the main cause of geomagnetic storms (GMS). GMS are strong perturbations of the Earth’s magnetic field that can affect space-borne and ground-based technological systems. The solar-terrestrial impact on modern technological systems is commonly known as Space Weather. Part of the research study described in this thesis was to investigate and establish a relationship between GMS (periods with Dst ≤ −50 nT) and their associated solar and interplanetary (IP) properties during solar cycle (SC) 23. Solar and IP geoeffective properties associated with or without CMEs were investigated and used to qualitatively characterise both intense and moderate storms. The results of this analysis specifically provide an estimate of the main sources of GMS during an average 11-year solar activity period. This study indicates that during SC 23, the majority of intense GMS (83%) were associated with CMEs, while the non-associated CME storms were dominant among moderate storms. GMS phenomena are the result of a complex and non-linear chaotic system involving the Sun, the IP medium, the magnetosphere and ionosphere, which make the prediction of these phenomena challenging. This thesis also explored the predictability of both the occurrence and strength of GMS. Due to their nonlinear driving mechanisms, the prediction of GMS was attempted by the use of neural network (NN) techniques, known for their non-linear modelling capabilities. To predict the occurrence of storms, a combination of solar and IP parameters were used as inputs in the NN model that proved to predict the occurrence of GMS with a probability of 87%. Using the solar wind (SW) and IP magnetic field (IMF) parameters, a separate NN-based model was developed to predict the storm-time strength as measured by the global Dst and ap geomagnetic indices, as well as by the locally measured K-index. The performance of the models was tested on data sets which were not part of the NN training process. The results obtained indicate that NN models provide a reliable alternative method for empirically predicting the occurrence and strength of GMS on the basis of solar and IP parameters. The demonstrated ability to predict the geoeffectiveness of solar and IP transient events is a key step in the goal towards improving space weather modelling and prediction.
- Full Text:
- Date Issued: 2011
Poverty attribution and reaction to income inequality in Nigeria: the case of Badia community in Lagos
- Authors: Ige, Kehinde Davies
- Date: 2011
- Subjects: Income distribution -- Nigeria , Poverty -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD (Sociology)
- Identifier: vital:11951 , http://hdl.handle.net/10353/329 , Income distribution -- Nigeria , Poverty -- Nigeria
- Description: This study was about the reaction of disadvantaged groups and persons to inequality and deprivation. Set in Badia, a low income community in Lagos, Nigeria, it investigates the main effects of community members’ attributions of causes of poverty in motivating or impeding their reaction to inequality. Relative Deprivation (RD) theory proposed that dissatisfaction with social outcomes depend on subjective feelings rather than objective criteria. However scholars found empirical difficulties in predicting collective action on the basis of RD. Resource Mobilization proponents argued on the contrary that feelings are not salient within the framework of action. The infusion of Social Identity Theory (SIT) into RD research however resolved the paradox of action with SIT’s argument that action was contingent upon the perception of permeability and legitimacy of inter-group structures. However, despite successes of SIT, scholars found that it was unable to predict the type of actions group members will take in response to injustice and the nature of possible actions. Propositions of RD and SIT were therefore suitable for integration into the proposition of Taylor & McKirnan’s (1984) Five Stage Model (FSM) of inter-group relations that reactions to RD feelings were predicated upon the dynamics of the social philosophy guiding stratification. Using an integrated RD, SIT and FSM framework, this study shows how disadvantaged group members’ responses to deprivation proceeded as predicted by the FSM from mutual acceptance to collective action mediated by their perception of causes of poverty. This complements the trend in the literature on reaction to inequality and it's almost ii exclusive focus on instrumental and affective concerns while neglecting the role of consensually shared beliefs in motivating or impeding action and willingness to act in response to injustice. The study hypothesized that the pattern of causal attributions of poverty of respondents will shape their ‘predisposition to act’ and the type of action they would engage in. The main hypothesis of the study therefore was that poverty attribution mediates the relationship between ‘feelings of injustice’ and ‘reaction to inequality’. For instance where respondents attribute poverty to individual or fatalistic factors they will adopt individual action whereas where attributions are structural, responses will be collective, where feelings of injustice were present. A survey was conducted using a five-level Likert scale to decipher respondents’ perceptions of feelings of injustice, their causal attribution of poverty, their levels of willingness to embark on collective action and actions taken in the preceding year. In the first stage of analysis, responses (n = 383) were reduced using Principal Components Analysis (PCA) to determine how questionnaire items contributed to variables under consideration. Subsequently, variables extracted were correlated and regressed. While bivariate correlation was used to test simple relationships between variables, a stepwise hierarchical regression analysis was used to decipher how sub-dimensions of poverty attribution mediate the relationship between respondents’ feelings of injustice and their willingness to embark on collective action entering variables in succession into the regression equation. Furthermore, a 1 x 3 x 5 Multivariate Analysis of Covariance (MANCOVA) was used to test the mediation effects of poverty attribution sub-dimensions on the relationship between injustice feelings and actions. The results showed iii that structural attribution was the preferred explanation for poverty among Badia residents, as this explanation was preferred by a majority of the respondents. It was also shown that while 96.9% of respondents used more than one causal attribution, a majority of structural attributors adopted fatalistic attribution as second choice of explanation for poverty. On the basis of the above, and in line with previous studies (Mann, 1970; Bobo, 1991), it was deduced that the possibility for radical action would be diminished as a result of this ‘dual/split consciousness’. The result further confirmed as hypothesized, that fatalistic attribution had a negative correlation with willingness to embark on collective action as respondents in the fatalistic condition were not willing to embark on collective action. However, respondents in the structural conditions were more willing to engage in collective action. While attributions predicted willingness to embark on collective action, MANCOVA showed that action proceeded in a continuum as predicted by the FSM. For example, while the introduction of fatalistic and individual attribution to the equation hypothesizing the relationship between injustice feelings and action showed that resultant actions were predominantly individual normative, post-hoc inclusion of the structural dimension to the equation showed an addition variance to the equation for collective action. This indicated that structural attributions enhance collective normative action. However, consistent with most studies in the literature, the results did not predict collective non-normative action1. Results indicated low adherence of subject to items eliciting collective action suggesting that past studies which reported high preference of collective action by disadvantaged groups may have been influenced by ‘social desirability effects’, given Topf’s (1995) assertion that what people say they will do is often not what they do but what they perceive as right in the particular situation. 1 The only notable exception is Boen & Vanbeselaere (1998) 2 A full discussion of lay explanations of poverty is reserved for chapter 4 of this thesis. iv The study however proposed on the basis of the salience of structural attributions that poverty attributions may become useful for Social Movement Organizations (SMOs) interested in fostering social change. However, while the study showed that attribution influences willingness to embark on action it does not show how attribution becomes salient in group membership. Thus there is a need for future studies to investigate how attribution affects group identification. Similarly, given the dearth of studies of the attribution of the ‘actual poor’ of poverty, it is necessary for future studies to test the validity of the result from the present study indicating stronger adherence to fatalistic than individualistic attributions of poverty among the disadvantaged. While many past studies of attribution and those of reaction to injustice have been on samples of middle-class adults in developed countries, or artificially created deprived groups, the present study being of the ‘real life’ poor in a Third World setting, provides evidence of ‘real world’ actions and attributions of people experiencing poverty.
- Full Text:
- Date Issued: 2011
- Authors: Ige, Kehinde Davies
- Date: 2011
- Subjects: Income distribution -- Nigeria , Poverty -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD (Sociology)
- Identifier: vital:11951 , http://hdl.handle.net/10353/329 , Income distribution -- Nigeria , Poverty -- Nigeria
- Description: This study was about the reaction of disadvantaged groups and persons to inequality and deprivation. Set in Badia, a low income community in Lagos, Nigeria, it investigates the main effects of community members’ attributions of causes of poverty in motivating or impeding their reaction to inequality. Relative Deprivation (RD) theory proposed that dissatisfaction with social outcomes depend on subjective feelings rather than objective criteria. However scholars found empirical difficulties in predicting collective action on the basis of RD. Resource Mobilization proponents argued on the contrary that feelings are not salient within the framework of action. The infusion of Social Identity Theory (SIT) into RD research however resolved the paradox of action with SIT’s argument that action was contingent upon the perception of permeability and legitimacy of inter-group structures. However, despite successes of SIT, scholars found that it was unable to predict the type of actions group members will take in response to injustice and the nature of possible actions. Propositions of RD and SIT were therefore suitable for integration into the proposition of Taylor & McKirnan’s (1984) Five Stage Model (FSM) of inter-group relations that reactions to RD feelings were predicated upon the dynamics of the social philosophy guiding stratification. Using an integrated RD, SIT and FSM framework, this study shows how disadvantaged group members’ responses to deprivation proceeded as predicted by the FSM from mutual acceptance to collective action mediated by their perception of causes of poverty. This complements the trend in the literature on reaction to inequality and it's almost ii exclusive focus on instrumental and affective concerns while neglecting the role of consensually shared beliefs in motivating or impeding action and willingness to act in response to injustice. The study hypothesized that the pattern of causal attributions of poverty of respondents will shape their ‘predisposition to act’ and the type of action they would engage in. The main hypothesis of the study therefore was that poverty attribution mediates the relationship between ‘feelings of injustice’ and ‘reaction to inequality’. For instance where respondents attribute poverty to individual or fatalistic factors they will adopt individual action whereas where attributions are structural, responses will be collective, where feelings of injustice were present. A survey was conducted using a five-level Likert scale to decipher respondents’ perceptions of feelings of injustice, their causal attribution of poverty, their levels of willingness to embark on collective action and actions taken in the preceding year. In the first stage of analysis, responses (n = 383) were reduced using Principal Components Analysis (PCA) to determine how questionnaire items contributed to variables under consideration. Subsequently, variables extracted were correlated and regressed. While bivariate correlation was used to test simple relationships between variables, a stepwise hierarchical regression analysis was used to decipher how sub-dimensions of poverty attribution mediate the relationship between respondents’ feelings of injustice and their willingness to embark on collective action entering variables in succession into the regression equation. Furthermore, a 1 x 3 x 5 Multivariate Analysis of Covariance (MANCOVA) was used to test the mediation effects of poverty attribution sub-dimensions on the relationship between injustice feelings and actions. The results showed iii that structural attribution was the preferred explanation for poverty among Badia residents, as this explanation was preferred by a majority of the respondents. It was also shown that while 96.9% of respondents used more than one causal attribution, a majority of structural attributors adopted fatalistic attribution as second choice of explanation for poverty. On the basis of the above, and in line with previous studies (Mann, 1970; Bobo, 1991), it was deduced that the possibility for radical action would be diminished as a result of this ‘dual/split consciousness’. The result further confirmed as hypothesized, that fatalistic attribution had a negative correlation with willingness to embark on collective action as respondents in the fatalistic condition were not willing to embark on collective action. However, respondents in the structural conditions were more willing to engage in collective action. While attributions predicted willingness to embark on collective action, MANCOVA showed that action proceeded in a continuum as predicted by the FSM. For example, while the introduction of fatalistic and individual attribution to the equation hypothesizing the relationship between injustice feelings and action showed that resultant actions were predominantly individual normative, post-hoc inclusion of the structural dimension to the equation showed an addition variance to the equation for collective action. This indicated that structural attributions enhance collective normative action. However, consistent with most studies in the literature, the results did not predict collective non-normative action1. Results indicated low adherence of subject to items eliciting collective action suggesting that past studies which reported high preference of collective action by disadvantaged groups may have been influenced by ‘social desirability effects’, given Topf’s (1995) assertion that what people say they will do is often not what they do but what they perceive as right in the particular situation. 1 The only notable exception is Boen & Vanbeselaere (1998) 2 A full discussion of lay explanations of poverty is reserved for chapter 4 of this thesis. iv The study however proposed on the basis of the salience of structural attributions that poverty attributions may become useful for Social Movement Organizations (SMOs) interested in fostering social change. However, while the study showed that attribution influences willingness to embark on action it does not show how attribution becomes salient in group membership. Thus there is a need for future studies to investigate how attribution affects group identification. Similarly, given the dearth of studies of the attribution of the ‘actual poor’ of poverty, it is necessary for future studies to test the validity of the result from the present study indicating stronger adherence to fatalistic than individualistic attributions of poverty among the disadvantaged. While many past studies of attribution and those of reaction to injustice have been on samples of middle-class adults in developed countries, or artificially created deprived groups, the present study being of the ‘real life’ poor in a Third World setting, provides evidence of ‘real world’ actions and attributions of people experiencing poverty.
- Full Text:
- Date Issued: 2011
The impact of toys as educative curriculum material on pre-service primary school Natural Sciences teachers' understanding of energy
- Authors: Meiring, Leslie Frank
- Date: 2011
- Subjects: Educational toys , Science -- Study and teaching (Primary) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9477 , http://hdl.handle.net/10948/1332 , Educational toys , Science -- Study and teaching (Primary) -- South Africa
- Description: In this study toys were used as educative curriculum material in an intervention on the topic of energy aimed at Intermediate Phase pre-service science teachers (n= 87) registered for a BEd degree at the Nelson Mandela Metropolitan University, South Africa. The intervention consisted of, amongst other elements, lectures, assignments and toy workshops, with the latter being a key driver in the process. The choice of toys as the educative curriculum material was informed by the fact that there is a huge variety of simple, reasonably priced and easily procured toys that are suitable to demonstrate the concept of energy from both theoretical and practical perspectives. The conclusions that can be drawn from the study are that the use of toys in the preparation of pre-service primary school teachers has the potential to substantially improve their subject content knowledge (SCK), pedagogical content knowledge (PCK), and their confidence related to these two constructs with respect to their understandings of energy. The data generated also suggest that when appropriate educative curriculum materials are integrated into a topic in science-teacher education, there may be a substantial positive impact on pre-service teachers‘ confidence in both their understanding of the science content and their perceptions of their ability to teach this content. An additional finding of the study was that, despite its popularity, status and usefulness over many years, the Science Teacher Efficacy Belief Instrument (STEBI-B) shows low sensitivity to measuring changes in efficacy as a consequence of the so-called ‗ceiling effect‘. The ceiling effect is a result of initial high scores which provide little opportunity to show iii substantial positive change as a result of an appropriate intervention that is designed to improve efficacy. While this study did not directly address this lacuna in STEBI-B, it made use of an innovative descriptive statistic, ‗percentage gain of potential‘, in an attempt to describe and interpret even small changes in efficacy as measured by STEBI-B.
- Full Text:
- Date Issued: 2011
- Authors: Meiring, Leslie Frank
- Date: 2011
- Subjects: Educational toys , Science -- Study and teaching (Primary) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9477 , http://hdl.handle.net/10948/1332 , Educational toys , Science -- Study and teaching (Primary) -- South Africa
- Description: In this study toys were used as educative curriculum material in an intervention on the topic of energy aimed at Intermediate Phase pre-service science teachers (n= 87) registered for a BEd degree at the Nelson Mandela Metropolitan University, South Africa. The intervention consisted of, amongst other elements, lectures, assignments and toy workshops, with the latter being a key driver in the process. The choice of toys as the educative curriculum material was informed by the fact that there is a huge variety of simple, reasonably priced and easily procured toys that are suitable to demonstrate the concept of energy from both theoretical and practical perspectives. The conclusions that can be drawn from the study are that the use of toys in the preparation of pre-service primary school teachers has the potential to substantially improve their subject content knowledge (SCK), pedagogical content knowledge (PCK), and their confidence related to these two constructs with respect to their understandings of energy. The data generated also suggest that when appropriate educative curriculum materials are integrated into a topic in science-teacher education, there may be a substantial positive impact on pre-service teachers‘ confidence in both their understanding of the science content and their perceptions of their ability to teach this content. An additional finding of the study was that, despite its popularity, status and usefulness over many years, the Science Teacher Efficacy Belief Instrument (STEBI-B) shows low sensitivity to measuring changes in efficacy as a consequence of the so-called ‗ceiling effect‘. The ceiling effect is a result of initial high scores which provide little opportunity to show iii substantial positive change as a result of an appropriate intervention that is designed to improve efficacy. While this study did not directly address this lacuna in STEBI-B, it made use of an innovative descriptive statistic, ‗percentage gain of potential‘, in an attempt to describe and interpret even small changes in efficacy as measured by STEBI-B.
- Full Text:
- Date Issued: 2011
(In)visibility and the exercise of power: a genealogy of the politics of drag spectacles in a small city in South Africa
- Authors: Marx, Jacqueline Greer
- Date: 2011
- Subjects: Female impersonators -- Research -- South Africa Male impersonators -- Research -- South Africa Apartheid -- South Africa -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3013 , http://hdl.handle.net/10962/d1002522
- Description: This study investigates the politics of homosexual visibility in dressing-up, cross-dressing and drag performances that take place in a small city in South Africa over a period of sixty years, beginning in the 1950s and the inception of apartheid policy, through the socio-political changes in the 1990s to the 21st century post-apartheid context. The study draws on Butler’s notion of performative resistance and adopts a Foucauldian genealogy to examine the conditions that make visibility possible and through which particular representations of homosexuality are articulated and read, or remain unread or misread. Information about dressing-up, cross-dressing and drag performance was obtained in interviews, from documentary evidence, and from audio-visual recordings of drag shows and gay and lesbian beauty pageant competitions. Semiotics and a Foucauldian approach to analysing discourse were used to interpret the written, spoken, and visual texts. In this study I argue that the state prohibition of homosexuality during apartheid meant that people could not admit to knowing about it, and this ‘not knowing’ provided a cover for homosexual behaviour in public. At this time, the threat of being identified was associated with police raids on private parties. In the 1990s, homosexual visibility was more viable than it had been in the past. However, the strategies that were adopted to negotiate public visibility at this time were tailored to appease normative sentiments rather than challenge them. I argue that, historically, race and gender have played a role in diminishing and exacerbating homosexual visibility and its politics. Addressing the potential for harm that is associated with homosexual visibility in the 21st century post-apartheid context, this study considers the circumstances in which invisibility is desirable.
- Full Text:
- Date Issued: 2011
- Authors: Marx, Jacqueline Greer
- Date: 2011
- Subjects: Female impersonators -- Research -- South Africa Male impersonators -- Research -- South Africa Apartheid -- South Africa -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3013 , http://hdl.handle.net/10962/d1002522
- Description: This study investigates the politics of homosexual visibility in dressing-up, cross-dressing and drag performances that take place in a small city in South Africa over a period of sixty years, beginning in the 1950s and the inception of apartheid policy, through the socio-political changes in the 1990s to the 21st century post-apartheid context. The study draws on Butler’s notion of performative resistance and adopts a Foucauldian genealogy to examine the conditions that make visibility possible and through which particular representations of homosexuality are articulated and read, or remain unread or misread. Information about dressing-up, cross-dressing and drag performance was obtained in interviews, from documentary evidence, and from audio-visual recordings of drag shows and gay and lesbian beauty pageant competitions. Semiotics and a Foucauldian approach to analysing discourse were used to interpret the written, spoken, and visual texts. In this study I argue that the state prohibition of homosexuality during apartheid meant that people could not admit to knowing about it, and this ‘not knowing’ provided a cover for homosexual behaviour in public. At this time, the threat of being identified was associated with police raids on private parties. In the 1990s, homosexual visibility was more viable than it had been in the past. However, the strategies that were adopted to negotiate public visibility at this time were tailored to appease normative sentiments rather than challenge them. I argue that, historically, race and gender have played a role in diminishing and exacerbating homosexual visibility and its politics. Addressing the potential for harm that is associated with homosexual visibility in the 21st century post-apartheid context, this study considers the circumstances in which invisibility is desirable.
- Full Text:
- Date Issued: 2011
An intervention for enhancing the mathematics teaching practices of grade four teachers in the Nelson Mandela Metropolitan area
- Authors: Botha, Adele
- Date: 2011
- Subjects: Mathematics -- Study and teaching , Mathematics , Mathematics -- Handbooks, manuals, etc , Mathematics teachers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9499 , http://hdl.handle.net/10948/d1008176 , Mathematics -- Study and teaching , Mathematics , Mathematics -- Handbooks, manuals, etc , Mathematics teachers
- Description: Mathematics is regarded as a driving force in economies worldwide. The performance of South African learners in mathematics over the past decade has highlighted that problems are being experienced across all grades. This situation needs to be addressed with urgency. The South African Department of Education stated that quality learning must be the objective for all grades. The implementation of good teaching practices plays a crucial role in improving the quality of education and in guiding learners towards quality learning. To achieve quality mathematics teaching and learning it is imperative to determine what good mathematics teaching practices are. The identification of good mathematic teaching practices will provide a yard stick to measure the mathematics teaching competency of teachers. This study identifies a set of good mathematics teaching practice indicators and evidences applicable to teachers in the Intermediate phase as a first contribution. These indicators and evidences frame the second research contribution: an assessment instrument entitled “A Classroom Observation Tool for Observing Mathematics Teaching Practices in Primary Schools”. As a third research contribution a generic profile of a Grade four mathematics teacher has been built. This generic profile has been built through an analysis of data gathered by means of self-assessment questionnaires completed by the research sample, as well as through applying the observation tool. The value of the generic profile lies in the identification of shared strengths and shared improvement opportunities in the mathematics teaching practice of the sample and as such, it forms the basis of a theory on Grade four mathematics teaching practice. The fourth research contribution is the design and application of an intervention that addresses the shared improvement opportunities. The research study concludes by comparing pre-intervention classroom observation data with post-intervention classroom observation data and reporting on the impact of the intervention.
- Full Text:
- Date Issued: 2011
- Authors: Botha, Adele
- Date: 2011
- Subjects: Mathematics -- Study and teaching , Mathematics , Mathematics -- Handbooks, manuals, etc , Mathematics teachers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9499 , http://hdl.handle.net/10948/d1008176 , Mathematics -- Study and teaching , Mathematics , Mathematics -- Handbooks, manuals, etc , Mathematics teachers
- Description: Mathematics is regarded as a driving force in economies worldwide. The performance of South African learners in mathematics over the past decade has highlighted that problems are being experienced across all grades. This situation needs to be addressed with urgency. The South African Department of Education stated that quality learning must be the objective for all grades. The implementation of good teaching practices plays a crucial role in improving the quality of education and in guiding learners towards quality learning. To achieve quality mathematics teaching and learning it is imperative to determine what good mathematics teaching practices are. The identification of good mathematic teaching practices will provide a yard stick to measure the mathematics teaching competency of teachers. This study identifies a set of good mathematics teaching practice indicators and evidences applicable to teachers in the Intermediate phase as a first contribution. These indicators and evidences frame the second research contribution: an assessment instrument entitled “A Classroom Observation Tool for Observing Mathematics Teaching Practices in Primary Schools”. As a third research contribution a generic profile of a Grade four mathematics teacher has been built. This generic profile has been built through an analysis of data gathered by means of self-assessment questionnaires completed by the research sample, as well as through applying the observation tool. The value of the generic profile lies in the identification of shared strengths and shared improvement opportunities in the mathematics teaching practice of the sample and as such, it forms the basis of a theory on Grade four mathematics teaching practice. The fourth research contribution is the design and application of an intervention that addresses the shared improvement opportunities. The research study concludes by comparing pre-intervention classroom observation data with post-intervention classroom observation data and reporting on the impact of the intervention.
- Full Text:
- Date Issued: 2011
An evaluation of the effectiveness of Walter Sisulu University's teaching practice as a context for student teachers' competence development
- Authors: Ntsaluba, Doris Nomonde
- Date: 2011
- Subjects: Teaching practice -- Student teacher
- Language: English
- Type: Thesis , Doctoral , D Ed
- Identifier: vital:18455 , http://hdl.handle.net/11260/d1007761
- Description: This study was aimed at evaluating the effectiveness of teaching practice as a context for the development of student teachers’ competences at Walter Sisulu University. The study was necessitated by the lack of information on whether teaching practice really provides an effective context or not. A literature study focusing on planning of teaching practice, preparation of student teachers for teaching practice, placement of student teachers for teaching practice, mentoring during teaching practice as well as supervision and assessment of teaching practice was conducted. The activity and situated learning theories provided a theoretical framework for studying teaching practice. The mixed-methods approach consisting of quantitative and qualitative approaches was used and data was collected through questionnaires and focus group discussions. The participants in the study were: thirty (30) student teachers in their third year of study; ten (10) host teachers who were hosting student teachers at the time of data collection for this study and ten (10) university supervisors responsible for teaching practice supervision. Data from closed-ended questionnaire items were analysed statistically. Frequencies and percentages were derived. Content analysis was used to analyse qualitative data. The results of the study revealed that there was a serious lack of communication between the university and the schools used for teaching practice and as a result student teachers were subjected to a wide range of treatment when they arrived at the schools. The findings also showed that student teachers were inadequately prepared for teaching practice. Student teachers were faced with serious challenges with regard to placement and there was no common programme of mentoring. The schools, as a result, did not provide a sufficiently-appropriate environment for teaching practice to become an effective context for student teachers‘ competence development. The recommendations made include suggestions for the improvement of the general organisation of teaching practice with the university and the schools working as partners in all the activities of teaching practice. The introduction of a formal programme for the preparation of student teachers for teaching practice is suggested and a teaching practice model is also proposed.
- Full Text:
- Date Issued: 2011
- Authors: Ntsaluba, Doris Nomonde
- Date: 2011
- Subjects: Teaching practice -- Student teacher
- Language: English
- Type: Thesis , Doctoral , D Ed
- Identifier: vital:18455 , http://hdl.handle.net/11260/d1007761
- Description: This study was aimed at evaluating the effectiveness of teaching practice as a context for the development of student teachers’ competences at Walter Sisulu University. The study was necessitated by the lack of information on whether teaching practice really provides an effective context or not. A literature study focusing on planning of teaching practice, preparation of student teachers for teaching practice, placement of student teachers for teaching practice, mentoring during teaching practice as well as supervision and assessment of teaching practice was conducted. The activity and situated learning theories provided a theoretical framework for studying teaching practice. The mixed-methods approach consisting of quantitative and qualitative approaches was used and data was collected through questionnaires and focus group discussions. The participants in the study were: thirty (30) student teachers in their third year of study; ten (10) host teachers who were hosting student teachers at the time of data collection for this study and ten (10) university supervisors responsible for teaching practice supervision. Data from closed-ended questionnaire items were analysed statistically. Frequencies and percentages were derived. Content analysis was used to analyse qualitative data. The results of the study revealed that there was a serious lack of communication between the university and the schools used for teaching practice and as a result student teachers were subjected to a wide range of treatment when they arrived at the schools. The findings also showed that student teachers were inadequately prepared for teaching practice. Student teachers were faced with serious challenges with regard to placement and there was no common programme of mentoring. The schools, as a result, did not provide a sufficiently-appropriate environment for teaching practice to become an effective context for student teachers‘ competence development. The recommendations made include suggestions for the improvement of the general organisation of teaching practice with the university and the schools working as partners in all the activities of teaching practice. The introduction of a formal programme for the preparation of student teachers for teaching practice is suggested and a teaching practice model is also proposed.
- Full Text:
- Date Issued: 2011
Time series models for paired comparisons
- Authors: Sjolander, Morne Rowan
- Date: 2011
- Subjects: Paired comparisons (Statistics)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10577 , http://hdl.handle.net/10948/d1012858
- Description: The method of paired comparisons is seen as a technique used to rank a set of objects with respect to an abstract or immeasurable property. To do this, the objects get to be compared two at a time. The results are input into a model, resulting in numbers known as weights being assigned to the objects. The weights are then used to rank the objects. The method of paired comparisons was first used for psychometric investigations. Various other applications of the method are also present, for example economic applications, and applications in sports statistics. This study involves taking paired comparison models and making them time-dependent. Not much research has been done in this area. Three new time series models for paired comparisons are created. Simulations are done to support the evidence obtained, and theoretical as well as practical examples are given to illustrate the results and to verify the efficiency of the new models. A literature study is given on the method of paired comparisons, as well as on the areas in which we apply our models. Our first two time series models for paired comparisons are the Linear-Trend Bradley- Terry Model and the Sinusoidal Bradley-Terry Model. We use the maximum likelihood approach to solve these models. We test our models using exact and randomly simulated data for various time periods and various numbers of objects. We adapt the Linear-Trend Bradley-Terry Model and received our third time series model for paired comparisons, the Log Linear-Trend Bradley-Terry Model. The daily maximum and minimum temperatures were received for Port Elizabeth, Uitenhage and Coega for 2005 until 2009. To evaluate the performance of the Linear-Trend Bradley-Terry Model and the Sinusoidal Bradley-Terry Model on estimating missing temperature data, we artificially remove observations of temperature from Coega’s temperature dataset for 2006 until 2008, and use various forms of these models to estimate the missing data points. The exchange rates for 2005 until 2008 between the following currencies: the Rand, Dollar, Euro, Pound and Yen, were obtained and various forms of our Log Linear-Trend Bradley-Terry Model are used to forecast the exchange rate for one day ahead for each month in 2006 until 2008. One of the features of this study is that we apply our time series models for paired comparisons to areas which comprise non-standard paired comparisons; and we want to encourage the use of the method of paired comparisons in a broader sense than what it is traditionally used for. The results of this study can be used in various other areas, like for example, in sports statistics, to rank the strength of sports players and predict their future scores; in Physics, to calculate weather risks of electricity generation, particularly risks related to nuclear power plants, and so forth, as well as in many other areas. It is hoped that this research will open the door to much more research in combining time series analysis with the method of paired comparisons.
- Full Text:
- Date Issued: 2011
- Authors: Sjolander, Morne Rowan
- Date: 2011
- Subjects: Paired comparisons (Statistics)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10577 , http://hdl.handle.net/10948/d1012858
- Description: The method of paired comparisons is seen as a technique used to rank a set of objects with respect to an abstract or immeasurable property. To do this, the objects get to be compared two at a time. The results are input into a model, resulting in numbers known as weights being assigned to the objects. The weights are then used to rank the objects. The method of paired comparisons was first used for psychometric investigations. Various other applications of the method are also present, for example economic applications, and applications in sports statistics. This study involves taking paired comparison models and making them time-dependent. Not much research has been done in this area. Three new time series models for paired comparisons are created. Simulations are done to support the evidence obtained, and theoretical as well as practical examples are given to illustrate the results and to verify the efficiency of the new models. A literature study is given on the method of paired comparisons, as well as on the areas in which we apply our models. Our first two time series models for paired comparisons are the Linear-Trend Bradley- Terry Model and the Sinusoidal Bradley-Terry Model. We use the maximum likelihood approach to solve these models. We test our models using exact and randomly simulated data for various time periods and various numbers of objects. We adapt the Linear-Trend Bradley-Terry Model and received our third time series model for paired comparisons, the Log Linear-Trend Bradley-Terry Model. The daily maximum and minimum temperatures were received for Port Elizabeth, Uitenhage and Coega for 2005 until 2009. To evaluate the performance of the Linear-Trend Bradley-Terry Model and the Sinusoidal Bradley-Terry Model on estimating missing temperature data, we artificially remove observations of temperature from Coega’s temperature dataset for 2006 until 2008, and use various forms of these models to estimate the missing data points. The exchange rates for 2005 until 2008 between the following currencies: the Rand, Dollar, Euro, Pound and Yen, were obtained and various forms of our Log Linear-Trend Bradley-Terry Model are used to forecast the exchange rate for one day ahead for each month in 2006 until 2008. One of the features of this study is that we apply our time series models for paired comparisons to areas which comprise non-standard paired comparisons; and we want to encourage the use of the method of paired comparisons in a broader sense than what it is traditionally used for. The results of this study can be used in various other areas, like for example, in sports statistics, to rank the strength of sports players and predict their future scores; in Physics, to calculate weather risks of electricity generation, particularly risks related to nuclear power plants, and so forth, as well as in many other areas. It is hoped that this research will open the door to much more research in combining time series analysis with the method of paired comparisons.
- Full Text:
- Date Issued: 2011
Evidence-informed clinical guidelines for nursing care practices related to the safety of the mechanically ventilated patient
- Authors: Jordan, Portia Janine
- Date: 2011
- Subjects: Respiratory intensive care -- South Africa -- Port Elizabeth , Respiratory therapy -- South Africa -- Port Elizabeth , Artificial respiration -- South Africa -- Port Elizabeth , Artificial respiration -- Nursing , Respirators (Medical equipment) -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10027 , http://hdl.handle.net/10948/1322 , Respiratory intensive care -- South Africa -- Port Elizabeth , Respiratory therapy -- South Africa -- Port Elizabeth , Artificial respiration -- South Africa -- Port Elizabeth , Artificial respiration -- Nursing , Respirators (Medical equipment) -- South Africa -- Port Elizabeth
- Description: An evidence-based approach to clinical practice aims to deliver appropriate care in an efficient manner to individual patients. This approach entails the integration of research evidence, clinical expertise and the interpretation of patients' needs and perspectives in making decisions about the best care modalities. The increased emphasis internationally on improved patient care and cost effectiveness in health care delivery highlighted the need for quality health services that have to be built upon the use of best evidence to inform practice and patient-care decision-making (McKenna, Ashton and Keeney, 2004:178). Critical care nursing science, a specialised branch of nursing, focusing on the care of the critically ill patient in a designated unit, is no exception to the drive to provide improved quality and cost-effective patient care. Critical care practitioners are seen to have a specialised knowledge base, specific skills in delivering advanced health care and a commitment to serve the critically ill patient. It is expected of them to be aware of new and emerging evidence about health disease processes, treatment modalities and technology used in the critical-care units. Due to the dynamic nature of a critical care unit, it is essential that every practitioner working in the unit, whether a novice professional nurse or senior unit manager, needs to be aware of the current evidence guiding their practices (Elliot, Aitken, Chaboyer, 2007:18). With reference to the critically ill patient who is connected to a mechanical ventilator, practices related to the nursing care of this group of patients, who mostly occupy the critical care units, should be based on the best evidence in order to provide cost-effective and quality care. The research study aimed to explore and describe four identified nursing care practices related to safety of a mechanically ventilated patient as performed by professional nurses in the critical care units in the Nelson Mandela Metropole. The identified nursing-care practices include: endotrachael tube placement verification, endotracheal tube cuff pressure monitoring, endotrachael tube suctioning and mechanical ventilator settings. This objective was operationalized in Stage One of the study, by using a quantitative, explorative, descriptive and contextual approach. A structured questionnaire was utilised to collect data from professional nurses working in critical care units. From the analysed data, it was decided to select the two nursing care practices that were done least according to the best recommended practice, namely endotracheal tube suctioning and endotracheal tube cuff pressure monitoring. Based on the results, systematic reviews were done respectively on the two nursing care practices. On completion of Stage One of the study, evidence-informed clinical guidelines for the two identified nursing care practices were developed. The clinical guidelines were based on the evidence found in conducting the systematic reviews. The draft clinical guidelines were reviewed by an expert panel. Feedback from the reviewers was considered to prepare the final evidence-informed clinical guidelines. Based on the clinical guidelines, two clinical algorithms were developed, which might be used at the patient's bedside and can assist in quick dissemination of the recommendations for practice. Ethical considerations were maintained throughout the study. The quality of the study was ensured in applying the principles of validity and reliability as well as performing a critical appraisal of all data collected during the systematic review. It is envisaged that the study findings be disseminated in the critical care units in the Nelson Mandela Metropole and published in peer reviewed journals.
- Full Text:
- Date Issued: 2011
- Authors: Jordan, Portia Janine
- Date: 2011
- Subjects: Respiratory intensive care -- South Africa -- Port Elizabeth , Respiratory therapy -- South Africa -- Port Elizabeth , Artificial respiration -- South Africa -- Port Elizabeth , Artificial respiration -- Nursing , Respirators (Medical equipment) -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10027 , http://hdl.handle.net/10948/1322 , Respiratory intensive care -- South Africa -- Port Elizabeth , Respiratory therapy -- South Africa -- Port Elizabeth , Artificial respiration -- South Africa -- Port Elizabeth , Artificial respiration -- Nursing , Respirators (Medical equipment) -- South Africa -- Port Elizabeth
- Description: An evidence-based approach to clinical practice aims to deliver appropriate care in an efficient manner to individual patients. This approach entails the integration of research evidence, clinical expertise and the interpretation of patients' needs and perspectives in making decisions about the best care modalities. The increased emphasis internationally on improved patient care and cost effectiveness in health care delivery highlighted the need for quality health services that have to be built upon the use of best evidence to inform practice and patient-care decision-making (McKenna, Ashton and Keeney, 2004:178). Critical care nursing science, a specialised branch of nursing, focusing on the care of the critically ill patient in a designated unit, is no exception to the drive to provide improved quality and cost-effective patient care. Critical care practitioners are seen to have a specialised knowledge base, specific skills in delivering advanced health care and a commitment to serve the critically ill patient. It is expected of them to be aware of new and emerging evidence about health disease processes, treatment modalities and technology used in the critical-care units. Due to the dynamic nature of a critical care unit, it is essential that every practitioner working in the unit, whether a novice professional nurse or senior unit manager, needs to be aware of the current evidence guiding their practices (Elliot, Aitken, Chaboyer, 2007:18). With reference to the critically ill patient who is connected to a mechanical ventilator, practices related to the nursing care of this group of patients, who mostly occupy the critical care units, should be based on the best evidence in order to provide cost-effective and quality care. The research study aimed to explore and describe four identified nursing care practices related to safety of a mechanically ventilated patient as performed by professional nurses in the critical care units in the Nelson Mandela Metropole. The identified nursing-care practices include: endotrachael tube placement verification, endotracheal tube cuff pressure monitoring, endotrachael tube suctioning and mechanical ventilator settings. This objective was operationalized in Stage One of the study, by using a quantitative, explorative, descriptive and contextual approach. A structured questionnaire was utilised to collect data from professional nurses working in critical care units. From the analysed data, it was decided to select the two nursing care practices that were done least according to the best recommended practice, namely endotracheal tube suctioning and endotracheal tube cuff pressure monitoring. Based on the results, systematic reviews were done respectively on the two nursing care practices. On completion of Stage One of the study, evidence-informed clinical guidelines for the two identified nursing care practices were developed. The clinical guidelines were based on the evidence found in conducting the systematic reviews. The draft clinical guidelines were reviewed by an expert panel. Feedback from the reviewers was considered to prepare the final evidence-informed clinical guidelines. Based on the clinical guidelines, two clinical algorithms were developed, which might be used at the patient's bedside and can assist in quick dissemination of the recommendations for practice. Ethical considerations were maintained throughout the study. The quality of the study was ensured in applying the principles of validity and reliability as well as performing a critical appraisal of all data collected during the systematic review. It is envisaged that the study findings be disseminated in the critical care units in the Nelson Mandela Metropole and published in peer reviewed journals.
- Full Text:
- Date Issued: 2011
Development of MgZnO-grown MOCVD for UV Photonic applications
- Authors: Talla, Kharouna
- Date: 2011
- Subjects: Photoluminescence , Photonics , Zinc oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10537 , http://hdl.handle.net/10948/d1012585 , Photoluminescence , Photonics , Zinc oxide
- Description: MgxZn1-xO has emerged as a material of great technological importance. Having a direct energy band gap that is tunable throughout much of the ultraviolet (UV) region of the spectrum from the near-UV (~370 nm) to the deep-UV (~176 nm), this compound is of interest for a variety of optoelectronic devices operating in this part of the electromagnetic spectrum. MgxZn1-xO offers advantages over the more mature compound semiconductor AlGaN which stem mainly from the unusually high exciton binding energy (60 meV in ZnO). In this study the growth of ZnO and MgxZn1-xO thin films using metal organic chemical vapour deposition (MOCVD) is systematically investigated. The films are mainly grown on c-Al2O3 and Si (100) and characterized using various techniques, such as photoluminescence (PL), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and auger electron spectroscopy (AES). The optical and the structural properties are essentially inspected in order to improve their quality. In this thesis the optimisation of ZnO grown using oxygen gas as a new oxidant in our reactor is investigated. The growth temperature and VI/II ratio are varied in order to find optimum parameters giving high quality layers. The effects of Si (100), Si (111), c- and r-sapphire, glass, GaAs and ZnO substrates on the optical, structural and morphological properties of ZnO thin films grown with tert-butanol (TBOH) is examined. Similar morphologies are observed for all substrates, with the films comprising hexagonal columns having cone shaped ends. The photoluminescence spectra are similar, but the various transitions have different relative intensities. It is clear that the different substrates influence neither the orientation of the films, nor the surface morphology, significantly. The photoluminescence hints at larger stacking fault densities in films grown on silicon and glass, however, as evidenced by stronger basal plane stacking fault-related luminescence at ~3.319 eV in the relevant low temperature photoluminescence spectra. The morphology changes with Mg incorporation, from hexagonal columnar structures to cubic faceted columns. From PL, the full with at half maximum is found to gradually increase with Mg content due to alloy broadening. The deep level emission (DLE) is observed to shift with Mg content. By changing the Mg content, the band gap of MgxZn1-xO film is tuned by ~450 meV, which provides an excellent opportunity for band gap engineering for optoelectronic applications. The c-lattice constant of ZnO (5.205 Å) decreases by only 0.6% when the Mg content reaches x=0.39. The introduction of Mg into ZnO is shown to increase the relative PL intensity of stacking fault-related transitions (at 3.314 eV for ZnO). This becomes the dominant near band edge emission. Using TEM a thin Mg rich layer is observed at the interface between the film and the Si or Al2O3. Temperature dependent PL measurements on layers with low Mg concentration (x=0.05 and 0.1) show that the main bound exciton peak exhibits an “s-shaped” temperature dependence, characteristic of localization in a disordered alloy. The origin of the PL line broadening of MgxZn1-xO (x≤0.04) is also analyzed with respect to alloy broadening, taking into account a random cation distribution and alloy clustering. The influence of various MOCVD growth parameters such as growth temperature and VI/II ratio is studied. Varying the temperature from 280 ˚C to 580 ˚C reveals strong morphological changes and optical degradation of the films. Low (<280 ˚C) and high (>580 ˚C) growth temperatures reduce the Mg incorporation. High VI/II ratios also decrease the Mg incorporation, as evidenced by the red-shift of the donor bound exciton (D°X) line. This is ascribed to a stronger premature reaction between (MeCp)2Mg and the oxidant or a preferential heterogeneous interaction between the Mg and oxygen species on the growth front. For both oxidizing agents (O2 and TBOH), the growth at 420 ˚C and a VI-II ratio of 60 on c-Al2O3 gave optimal quality layers in terms of their optical and structural quality. A comparison of films grown using TBOH and O2 gas as oxidizing agent shows no major difference in terms of Mg incorporation. The effect of annealing, the inclusion of a buffer layer and the influence of growth rate on the properties MgxZn1-xO thin films are also reported.
- Full Text:
- Date Issued: 2011
- Authors: Talla, Kharouna
- Date: 2011
- Subjects: Photoluminescence , Photonics , Zinc oxide
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10537 , http://hdl.handle.net/10948/d1012585 , Photoluminescence , Photonics , Zinc oxide
- Description: MgxZn1-xO has emerged as a material of great technological importance. Having a direct energy band gap that is tunable throughout much of the ultraviolet (UV) region of the spectrum from the near-UV (~370 nm) to the deep-UV (~176 nm), this compound is of interest for a variety of optoelectronic devices operating in this part of the electromagnetic spectrum. MgxZn1-xO offers advantages over the more mature compound semiconductor AlGaN which stem mainly from the unusually high exciton binding energy (60 meV in ZnO). In this study the growth of ZnO and MgxZn1-xO thin films using metal organic chemical vapour deposition (MOCVD) is systematically investigated. The films are mainly grown on c-Al2O3 and Si (100) and characterized using various techniques, such as photoluminescence (PL), x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and auger electron spectroscopy (AES). The optical and the structural properties are essentially inspected in order to improve their quality. In this thesis the optimisation of ZnO grown using oxygen gas as a new oxidant in our reactor is investigated. The growth temperature and VI/II ratio are varied in order to find optimum parameters giving high quality layers. The effects of Si (100), Si (111), c- and r-sapphire, glass, GaAs and ZnO substrates on the optical, structural and morphological properties of ZnO thin films grown with tert-butanol (TBOH) is examined. Similar morphologies are observed for all substrates, with the films comprising hexagonal columns having cone shaped ends. The photoluminescence spectra are similar, but the various transitions have different relative intensities. It is clear that the different substrates influence neither the orientation of the films, nor the surface morphology, significantly. The photoluminescence hints at larger stacking fault densities in films grown on silicon and glass, however, as evidenced by stronger basal plane stacking fault-related luminescence at ~3.319 eV in the relevant low temperature photoluminescence spectra. The morphology changes with Mg incorporation, from hexagonal columnar structures to cubic faceted columns. From PL, the full with at half maximum is found to gradually increase with Mg content due to alloy broadening. The deep level emission (DLE) is observed to shift with Mg content. By changing the Mg content, the band gap of MgxZn1-xO film is tuned by ~450 meV, which provides an excellent opportunity for band gap engineering for optoelectronic applications. The c-lattice constant of ZnO (5.205 Å) decreases by only 0.6% when the Mg content reaches x=0.39. The introduction of Mg into ZnO is shown to increase the relative PL intensity of stacking fault-related transitions (at 3.314 eV for ZnO). This becomes the dominant near band edge emission. Using TEM a thin Mg rich layer is observed at the interface between the film and the Si or Al2O3. Temperature dependent PL measurements on layers with low Mg concentration (x=0.05 and 0.1) show that the main bound exciton peak exhibits an “s-shaped” temperature dependence, characteristic of localization in a disordered alloy. The origin of the PL line broadening of MgxZn1-xO (x≤0.04) is also analyzed with respect to alloy broadening, taking into account a random cation distribution and alloy clustering. The influence of various MOCVD growth parameters such as growth temperature and VI/II ratio is studied. Varying the temperature from 280 ˚C to 580 ˚C reveals strong morphological changes and optical degradation of the films. Low (<280 ˚C) and high (>580 ˚C) growth temperatures reduce the Mg incorporation. High VI/II ratios also decrease the Mg incorporation, as evidenced by the red-shift of the donor bound exciton (D°X) line. This is ascribed to a stronger premature reaction between (MeCp)2Mg and the oxidant or a preferential heterogeneous interaction between the Mg and oxygen species on the growth front. For both oxidizing agents (O2 and TBOH), the growth at 420 ˚C and a VI-II ratio of 60 on c-Al2O3 gave optimal quality layers in terms of their optical and structural quality. A comparison of films grown using TBOH and O2 gas as oxidizing agent shows no major difference in terms of Mg incorporation. The effect of annealing, the inclusion of a buffer layer and the influence of growth rate on the properties MgxZn1-xO thin films are also reported.
- Full Text:
- Date Issued: 2011
Strategies to create a post-merged organisational culture conducive to effective performance management
- Authors: Paul, Gary William
- Date: 2011
- Subjects: Corporate culture , Organizational change , Organizational effectiveness
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9385 , http://hdl.handle.net/10948/d1010857 , Corporate culture , Organizational change , Organizational effectiveness
- Description: Mergers have been described as the most complex business process that an organisation can be faced with, requiring executives and other stakeholders to discharge the promise of a more successful merged organisation. However, several studies have highlighted the factors that led to the demise of the merged organisations. One of the often quoted and frequently blamed aspects related to merger failure has been the lack of effective post-merged organisational culture integration and alignment. Where mergers have been successful, it was attributed to a structured approach to integrating and aligning all aspects related to organisational culture thus ensuring the creation of a high performing organisation, conducive to effective performance management. The main research problem in this study centred around the identification of strategies that could be used to design an integrated model for creating a post-merged organisational culture which is conducive to effectively managing performance. To achieve this objective, the following approaches were adopted: A literature study was conducted with the view to identifying the challenges facing merged organisations in general and post-merged South African Higher Education institutions in particular. The researcher also conducted interviews with senior HR practitioner at the institutions participating in this study to gain insights into their experiences of performance within their merged institutions. The institutions involved in this study were Nelson Mandela Metropolitan University (NMMU), Cape Peninsula University of Technology (CPUT and Durban University of Technology (DUT). The insights gleaned from these interviews were incorporated into the survey questionnaire. The literature study also concerned itself with the identification of strategies that merged organisations could use in its pursuit of organisational culture alignment and integration. These strategies included conducting critical pre-merger assessments or due-diligence studies, adopting structured approaches to dealing with resistance to change, employee engagement, the design, implementation and communication of monitoring and evaluation of merger success measures as well as several other moderating variables referred to in figure 1.2. In terms of sub-problem six of the study, the findings of sub-problems one, two and five were used to develop an eight-step integrated theoretical model to create an organisational culture conducive to effective performance management in a post-merged environment. The model served as a basis for the design of a survey questionnaire. The questionnaire was used to ascertain the extent to which respondents from the three participating institutions (NMMU, CPUT and DUT), perceived the various strategies as being important in establishing a post-merged organisational culture conducive to effective performance management. The results that emerged from the empirical study showed a strong concurrence with the strategies identified in the literature study and included in the integrated theoretical model. The quantitative and qualitative results from the empirical study where incorporated into the integrated theoretical model, which lead to a refined Eight-Step Integrated Post-merged Organisational Culture Creation Model as depicted in Figure 7.1 with associated details in Figure 7.2.
- Full Text:
- Date Issued: 2011
- Authors: Paul, Gary William
- Date: 2011
- Subjects: Corporate culture , Organizational change , Organizational effectiveness
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9385 , http://hdl.handle.net/10948/d1010857 , Corporate culture , Organizational change , Organizational effectiveness
- Description: Mergers have been described as the most complex business process that an organisation can be faced with, requiring executives and other stakeholders to discharge the promise of a more successful merged organisation. However, several studies have highlighted the factors that led to the demise of the merged organisations. One of the often quoted and frequently blamed aspects related to merger failure has been the lack of effective post-merged organisational culture integration and alignment. Where mergers have been successful, it was attributed to a structured approach to integrating and aligning all aspects related to organisational culture thus ensuring the creation of a high performing organisation, conducive to effective performance management. The main research problem in this study centred around the identification of strategies that could be used to design an integrated model for creating a post-merged organisational culture which is conducive to effectively managing performance. To achieve this objective, the following approaches were adopted: A literature study was conducted with the view to identifying the challenges facing merged organisations in general and post-merged South African Higher Education institutions in particular. The researcher also conducted interviews with senior HR practitioner at the institutions participating in this study to gain insights into their experiences of performance within their merged institutions. The institutions involved in this study were Nelson Mandela Metropolitan University (NMMU), Cape Peninsula University of Technology (CPUT and Durban University of Technology (DUT). The insights gleaned from these interviews were incorporated into the survey questionnaire. The literature study also concerned itself with the identification of strategies that merged organisations could use in its pursuit of organisational culture alignment and integration. These strategies included conducting critical pre-merger assessments or due-diligence studies, adopting structured approaches to dealing with resistance to change, employee engagement, the design, implementation and communication of monitoring and evaluation of merger success measures as well as several other moderating variables referred to in figure 1.2. In terms of sub-problem six of the study, the findings of sub-problems one, two and five were used to develop an eight-step integrated theoretical model to create an organisational culture conducive to effective performance management in a post-merged environment. The model served as a basis for the design of a survey questionnaire. The questionnaire was used to ascertain the extent to which respondents from the three participating institutions (NMMU, CPUT and DUT), perceived the various strategies as being important in establishing a post-merged organisational culture conducive to effective performance management. The results that emerged from the empirical study showed a strong concurrence with the strategies identified in the literature study and included in the integrated theoretical model. The quantitative and qualitative results from the empirical study where incorporated into the integrated theoretical model, which lead to a refined Eight-Step Integrated Post-merged Organisational Culture Creation Model as depicted in Figure 7.1 with associated details in Figure 7.2.
- Full Text:
- Date Issued: 2011
Repulsive-attractive models for the impact of two predators on prey species varying in anti-predator response
- Authors: Ddumba, Hassan
- Date: 2011
- Subjects: Predation (Biology) -- Mathematical models , Wildlife management -- Mathematical models , Pattern formation (Biology) , Predatory animals -- Ecology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10506 , http://hdl.handle.net/10948/d1010995 , Predation (Biology) -- Mathematical models , Wildlife management -- Mathematical models , Pattern formation (Biology) , Predatory animals -- Ecology
- Description: This study considers the dynamical interaction of two predatory carnivores (Lions (Panthera leo) and Spotted Hyaenas (Crocuta crocuta)) and three of their common prey (Buffalo (Syncerus caffer), Warthog (Phacochoerus africanus) and Kudu (Tragelaphus strepsiceros)). The dependence on spatial structure of species’ interaction stimulated the author to formulate reaction-diffusion models to explain the dynamics of predator-prey relationships in ecology. These models were used to predict and explain the effect of threshold populations, predator additional food and prey refuge on the general species’ dynamics. Vital parameters that model additional food to predators, prey refuge and population thresholds were given due attention in the analyses. The stability of a predator-prey model for an ecosystem faced with a prey out-flux which is analogous to and modelled as an Allee effect was investigated. The results highlight the bounds for the conversion efficiency of prey biomass to predator biomass (fertility gain) for which stability of the three species ecosystem model can be attained. Global stability analysis results showed that the prey (warthog) population density should exceed the sum of its carrying capacity and threshold value minus its equilibrium value i.e., W >(Kw + $) −W . This result shows that the warthog’s equilibrium population density is bounded above by population thresholds, i.e., W < (Kw+$). Besides showing the occurrence under parameter space of the so-called paradox of enrichment, early indicators of chaos can also be deduced. In addition, numerical results revealed stable oscillatory behaviour and stable spirals of the species as predator fertility rate, mortality rate and prey threshold were varied. The stabilising effect of prey refuge due to variations in predator fertility and proportion of prey in the refuge was studied. Formulation and analysis of a robust mathematical model for two predators having an overlapping dietary niche were also done. The Beddington-DeAngelis functional and numerical responses which are relevant in addressing the Principle of Competitive Exclusion as species interact were incorporated in the model. The stabilizing effect of additional food in relation to the relative diffusivity D, and wave number k, was investigated. Stability, dissipativity, permanence, persistence and periodicity of the model were studied using the routine and limit cycle perturbation methods. The periodic solutions (b 1 and b 3), which influence the dispersal rate (') of the interacting species, have been shown to be controlled by the wave number. For stability, and in order to overcome predator natural mortality, the nutritional value of predator additional food has been shown to be of high quality that can enhance predator fertility gain. The threshold relationships between various ecosystem parameters and the carrying capacity of the game park for the prey species were also deduced to ensure ecosystem persistence. Besides revealing irregular periodic travelling wave behaviour due to predator interference, numerical results also show oscillatory temporal dynamics resulting from additional food supplements combined with high predation rates.
- Full Text:
- Date Issued: 2011
- Authors: Ddumba, Hassan
- Date: 2011
- Subjects: Predation (Biology) -- Mathematical models , Wildlife management -- Mathematical models , Pattern formation (Biology) , Predatory animals -- Ecology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10506 , http://hdl.handle.net/10948/d1010995 , Predation (Biology) -- Mathematical models , Wildlife management -- Mathematical models , Pattern formation (Biology) , Predatory animals -- Ecology
- Description: This study considers the dynamical interaction of two predatory carnivores (Lions (Panthera leo) and Spotted Hyaenas (Crocuta crocuta)) and three of their common prey (Buffalo (Syncerus caffer), Warthog (Phacochoerus africanus) and Kudu (Tragelaphus strepsiceros)). The dependence on spatial structure of species’ interaction stimulated the author to formulate reaction-diffusion models to explain the dynamics of predator-prey relationships in ecology. These models were used to predict and explain the effect of threshold populations, predator additional food and prey refuge on the general species’ dynamics. Vital parameters that model additional food to predators, prey refuge and population thresholds were given due attention in the analyses. The stability of a predator-prey model for an ecosystem faced with a prey out-flux which is analogous to and modelled as an Allee effect was investigated. The results highlight the bounds for the conversion efficiency of prey biomass to predator biomass (fertility gain) for which stability of the three species ecosystem model can be attained. Global stability analysis results showed that the prey (warthog) population density should exceed the sum of its carrying capacity and threshold value minus its equilibrium value i.e., W >(Kw + $) −W . This result shows that the warthog’s equilibrium population density is bounded above by population thresholds, i.e., W < (Kw+$). Besides showing the occurrence under parameter space of the so-called paradox of enrichment, early indicators of chaos can also be deduced. In addition, numerical results revealed stable oscillatory behaviour and stable spirals of the species as predator fertility rate, mortality rate and prey threshold were varied. The stabilising effect of prey refuge due to variations in predator fertility and proportion of prey in the refuge was studied. Formulation and analysis of a robust mathematical model for two predators having an overlapping dietary niche were also done. The Beddington-DeAngelis functional and numerical responses which are relevant in addressing the Principle of Competitive Exclusion as species interact were incorporated in the model. The stabilizing effect of additional food in relation to the relative diffusivity D, and wave number k, was investigated. Stability, dissipativity, permanence, persistence and periodicity of the model were studied using the routine and limit cycle perturbation methods. The periodic solutions (b 1 and b 3), which influence the dispersal rate (') of the interacting species, have been shown to be controlled by the wave number. For stability, and in order to overcome predator natural mortality, the nutritional value of predator additional food has been shown to be of high quality that can enhance predator fertility gain. The threshold relationships between various ecosystem parameters and the carrying capacity of the game park for the prey species were also deduced to ensure ecosystem persistence. Besides revealing irregular periodic travelling wave behaviour due to predator interference, numerical results also show oscillatory temporal dynamics resulting from additional food supplements combined with high predation rates.
- Full Text:
- Date Issued: 2011
Oil enclave economy and sexual liaisons in Nigeria's Niger Delta region
- Authors: Gandu, Yohanna Kagoro
- Date: 2011
- Subjects: Women -- Violence against -- Nigeria Abused women -- Nigeria Sexual abuse victims -- Nigeria Prostitution -- Nigeria Oil industries -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3318 , http://hdl.handle.net/10962/d1003106
- Description: This thesis examines the intersection of oil enclave economy and the phenomenon of sexual liaisons in Nigeria’s Niger Delta region. The particular focus of this thesis is on the extent to which oil enclavity contributes to the emergence of sexual liaisons between local women and expatriate oil workers. Despite the fact that the Nigerian oil industry has been subjected to considerable scholarly debate for over five decades, this aspect of the social dimension of oil has not received adequate scholarly attention. Gender-specific discourse has tended to focus more on women protest. Other aspects, such as gender-specific violence that women in the region have had to live with, are either ignored or poorly articulated. Picketing of oil platforms by protesting women is celebrated as signs that women are active in the struggle against oil Transnational Companies (TNCs). While women protest is a significant struggle against oil TNCs, it has the potential of blurring our intellectual focus on the specific challenges confronting women in the Niger Delta. This study shows that since the inauguration of the Willink Commission in 1957, national palliatives meant to alleviate poverty in the Niger Delta region have not been gender sensitive. A review of the 1957 Willink Commission and others that came after it shows that the Nigerian state is yet to address the peculiar problems that the oil industry has brought to the women folk in the region. The paradox is that while oil provides enormous wealth and means of patronage to the Nigerian state elite, the oil TNCs, and better paid expatriate oil workers, a large section of the local Oil Bearing Communities (OBCs), especially women and unemployed youth, are not only dispossessed but survive in an environment characterised by anxiety and misery. With limited survival alternatives, youths resort to violent protest including oil thefts and bunkering. Local women are also immersed in this debacle because some of them resort to sexual liaisons with economically empowered expatriate oil workers as an alternative means of survival. This study therefore shifts the focus to women by exploring the extent to which sexual liaison reflects the contradictions in the enclave oil economy. The study employed an enclave economy conceptual framework to demonstrate that oil extractive activities compromise and distort the local economies of OBCs. This situation compels local women to seek for alternative means of survival by entering into sexual liaisons with more financially privileged expatriate oil workers. The study reviewed relevant secondary documentary sources of data. Further, it employed primary data collection techniques which include in-depth interviews/life histories, ethnographic observations, focus group discussions, and visual sociology. Besides obtaining the social profile and challenges facing the women involved in sexual liaisons with expatriate oil workers, the study provides an outline of participants’ narratives on the different social and economic dimensions of the intersection of oil enclave economy and sexual liaisons. The study found that some of the women involved in sexual liaisons with expatriate oil workers have been abandoned with ‘fatherless’ children. Some of them have also been rejected by their immediate family members and, in some cases, by their community. The study also found that the phenomenon of sexual liaisons and the incidents of abandoned ‘fatherless’ children that result from the practice, has over the years been played out through local resentment against oil TNCs and their expatriate employees. This finding helps to fill the gap in narratives and to make sense of the civic revolt and deepening instability in the Niger Delta region.
- Full Text:
- Date Issued: 2011
- Authors: Gandu, Yohanna Kagoro
- Date: 2011
- Subjects: Women -- Violence against -- Nigeria Abused women -- Nigeria Sexual abuse victims -- Nigeria Prostitution -- Nigeria Oil industries -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3318 , http://hdl.handle.net/10962/d1003106
- Description: This thesis examines the intersection of oil enclave economy and the phenomenon of sexual liaisons in Nigeria’s Niger Delta region. The particular focus of this thesis is on the extent to which oil enclavity contributes to the emergence of sexual liaisons between local women and expatriate oil workers. Despite the fact that the Nigerian oil industry has been subjected to considerable scholarly debate for over five decades, this aspect of the social dimension of oil has not received adequate scholarly attention. Gender-specific discourse has tended to focus more on women protest. Other aspects, such as gender-specific violence that women in the region have had to live with, are either ignored or poorly articulated. Picketing of oil platforms by protesting women is celebrated as signs that women are active in the struggle against oil Transnational Companies (TNCs). While women protest is a significant struggle against oil TNCs, it has the potential of blurring our intellectual focus on the specific challenges confronting women in the Niger Delta. This study shows that since the inauguration of the Willink Commission in 1957, national palliatives meant to alleviate poverty in the Niger Delta region have not been gender sensitive. A review of the 1957 Willink Commission and others that came after it shows that the Nigerian state is yet to address the peculiar problems that the oil industry has brought to the women folk in the region. The paradox is that while oil provides enormous wealth and means of patronage to the Nigerian state elite, the oil TNCs, and better paid expatriate oil workers, a large section of the local Oil Bearing Communities (OBCs), especially women and unemployed youth, are not only dispossessed but survive in an environment characterised by anxiety and misery. With limited survival alternatives, youths resort to violent protest including oil thefts and bunkering. Local women are also immersed in this debacle because some of them resort to sexual liaisons with economically empowered expatriate oil workers as an alternative means of survival. This study therefore shifts the focus to women by exploring the extent to which sexual liaison reflects the contradictions in the enclave oil economy. The study employed an enclave economy conceptual framework to demonstrate that oil extractive activities compromise and distort the local economies of OBCs. This situation compels local women to seek for alternative means of survival by entering into sexual liaisons with more financially privileged expatriate oil workers. The study reviewed relevant secondary documentary sources of data. Further, it employed primary data collection techniques which include in-depth interviews/life histories, ethnographic observations, focus group discussions, and visual sociology. Besides obtaining the social profile and challenges facing the women involved in sexual liaisons with expatriate oil workers, the study provides an outline of participants’ narratives on the different social and economic dimensions of the intersection of oil enclave economy and sexual liaisons. The study found that some of the women involved in sexual liaisons with expatriate oil workers have been abandoned with ‘fatherless’ children. Some of them have also been rejected by their immediate family members and, in some cases, by their community. The study also found that the phenomenon of sexual liaisons and the incidents of abandoned ‘fatherless’ children that result from the practice, has over the years been played out through local resentment against oil TNCs and their expatriate employees. This finding helps to fill the gap in narratives and to make sense of the civic revolt and deepening instability in the Niger Delta region.
- Full Text:
- Date Issued: 2011
Economics of land reform models used in Mashonaland Central Province of Zimbabwe
- Authors: Musemwa, Lovemore
- Date: 2011
- Subjects: Land reform -- Zimbabwe , Agricultural productivity -- Zimbabwe , Land tenure -- Zimbabwe , Infrastructure (Economics) -- Government policy -- Zimbabwe , Land reform beneficiaries -- Zimbabwe , Land use -- Economic aspects -- Zimbabwe , Field crops -- Zimbabwe , Data envelopment analysis -- Zimbabwe , Land settlement -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11168 , http://hdl.handle.net/10353/435 , Land reform -- Zimbabwe , Agricultural productivity -- Zimbabwe , Land tenure -- Zimbabwe , Infrastructure (Economics) -- Government policy -- Zimbabwe , Land reform beneficiaries -- Zimbabwe , Land use -- Economic aspects -- Zimbabwe , Field crops -- Zimbabwe , Data envelopment analysis -- Zimbabwe , Land settlement -- Zimbabwe
- Description: The land reform that has unfolded in Zimbabwe since 1980 used different models and had diverse consequences. Since the implementation of the fast tract land reform programme in 2000, Zimbabwe experienced heavy reduction in yield and output at farm level that led to a 70% shortfall in production to meet annual food requirements (Richardson, 2005). The economic crisis in Zimbabwe has been characterized by worsening food insecurity especially in the rural areas where harvests continue to be poor. In the beef sector, Zimbabwe has failed to meet its export quota to the EU. The shortfall in production to meet annual food requirements shows a very grim situation but do not tell us about the performance of resettled farmers who now occupy much of the productive land. The broad objective of the study was to determine and compare the production efficiency of resettled farmers in Zimbabwe across land reform models. In addition, the study determined land use intensity. The study was conducted in the Mashonaland Central Province of Zimbabwe mainly because a wide variety of field crops were grown by resettled farmers. The respondents were stratified into three groups. These were: beneficiaries of land reform before 2000 (resettle scheme), fast track A1 model and fast track A2 model. The three models differ on how they were implemented and supported and this might result in different efficiencies of the models. A total of 245 copies structured questionnaire were administered on the resettled farmers from June to September 2010. Descriptive statistics was applied to the basic characteristics of the sampled households. The effect of model of land reform, gender of the household head, marital status, age of the household head, education, household size, religion, dependence ratio, whether the farmer was fulltime or part-time in farming, experience of the farmers in farming at that environment, total land size owned by the farmers and soil type on revenue per hectare and land use rate were determined using the GLM procedure of SAS (2003). Significance differences between least-square group means were compared using the PDIFF test of SAS (2003). The relationship between Revenue and land utilization was examined using the Pearson‟s correlations analysis. Dependance between response variables that had an effect on either revenue per hectare or land utilization with all the other response variables was tested using the Chi-square test for dependance. To find the effect of arable land used and herd size on revenue per hectare and land use the RSREG Procedure of SAS (2003) was used. Input oriented DEA model under the assumption of constant return to scale was used to estimate efficiency in this study. To identify factors that influence efficiency, a Tobit model censored at zero was selected. The mean land use rate varied significantly (p<0.05) with the land reform model with A2 having highest land use rate of 67%. The A1 and old resettlement households had land use rates of 53% and 46%, respectively. Sex, marital status, age of the household head, education and household size significantly affected land use (P<0.05). Revenue per hectare was not affected by any the factors that were inputted in the model. Results from the DEA approach showed that A2 farmers (large land owners) had an average technical efficiency score of 0.839, while the lowest ranking model (A1) had an average score of 0.618. Small land holders (A1 and the old resettled farmers) are on average less cost-efficient than large land owners, with a score of 0.29 for the former compared with 0.45 for the latter. From the factors that were entered in the Tobit model, age of household head, excellent production knowledge and farmer status affected technical efficiency whereas allocative efficiency was only affected by good production knowledge, farm size, arable land owned and area under cultivation. Factors which affected economic efficiency of the resettled farmers are secondary education, household size, farm size, cultivated area and arable land owned. None of the included socio-economic variables has significant effects on the allocative and economic efficiency of the resettled farmers. Thus, the allocative and economic inefficiencies of the farmers might be accounted for by other natural and environmental factors which were not captured in the model.
- Full Text:
- Date Issued: 2011
- Authors: Musemwa, Lovemore
- Date: 2011
- Subjects: Land reform -- Zimbabwe , Agricultural productivity -- Zimbabwe , Land tenure -- Zimbabwe , Infrastructure (Economics) -- Government policy -- Zimbabwe , Land reform beneficiaries -- Zimbabwe , Land use -- Economic aspects -- Zimbabwe , Field crops -- Zimbabwe , Data envelopment analysis -- Zimbabwe , Land settlement -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11168 , http://hdl.handle.net/10353/435 , Land reform -- Zimbabwe , Agricultural productivity -- Zimbabwe , Land tenure -- Zimbabwe , Infrastructure (Economics) -- Government policy -- Zimbabwe , Land reform beneficiaries -- Zimbabwe , Land use -- Economic aspects -- Zimbabwe , Field crops -- Zimbabwe , Data envelopment analysis -- Zimbabwe , Land settlement -- Zimbabwe
- Description: The land reform that has unfolded in Zimbabwe since 1980 used different models and had diverse consequences. Since the implementation of the fast tract land reform programme in 2000, Zimbabwe experienced heavy reduction in yield and output at farm level that led to a 70% shortfall in production to meet annual food requirements (Richardson, 2005). The economic crisis in Zimbabwe has been characterized by worsening food insecurity especially in the rural areas where harvests continue to be poor. In the beef sector, Zimbabwe has failed to meet its export quota to the EU. The shortfall in production to meet annual food requirements shows a very grim situation but do not tell us about the performance of resettled farmers who now occupy much of the productive land. The broad objective of the study was to determine and compare the production efficiency of resettled farmers in Zimbabwe across land reform models. In addition, the study determined land use intensity. The study was conducted in the Mashonaland Central Province of Zimbabwe mainly because a wide variety of field crops were grown by resettled farmers. The respondents were stratified into three groups. These were: beneficiaries of land reform before 2000 (resettle scheme), fast track A1 model and fast track A2 model. The three models differ on how they were implemented and supported and this might result in different efficiencies of the models. A total of 245 copies structured questionnaire were administered on the resettled farmers from June to September 2010. Descriptive statistics was applied to the basic characteristics of the sampled households. The effect of model of land reform, gender of the household head, marital status, age of the household head, education, household size, religion, dependence ratio, whether the farmer was fulltime or part-time in farming, experience of the farmers in farming at that environment, total land size owned by the farmers and soil type on revenue per hectare and land use rate were determined using the GLM procedure of SAS (2003). Significance differences between least-square group means were compared using the PDIFF test of SAS (2003). The relationship between Revenue and land utilization was examined using the Pearson‟s correlations analysis. Dependance between response variables that had an effect on either revenue per hectare or land utilization with all the other response variables was tested using the Chi-square test for dependance. To find the effect of arable land used and herd size on revenue per hectare and land use the RSREG Procedure of SAS (2003) was used. Input oriented DEA model under the assumption of constant return to scale was used to estimate efficiency in this study. To identify factors that influence efficiency, a Tobit model censored at zero was selected. The mean land use rate varied significantly (p<0.05) with the land reform model with A2 having highest land use rate of 67%. The A1 and old resettlement households had land use rates of 53% and 46%, respectively. Sex, marital status, age of the household head, education and household size significantly affected land use (P<0.05). Revenue per hectare was not affected by any the factors that were inputted in the model. Results from the DEA approach showed that A2 farmers (large land owners) had an average technical efficiency score of 0.839, while the lowest ranking model (A1) had an average score of 0.618. Small land holders (A1 and the old resettled farmers) are on average less cost-efficient than large land owners, with a score of 0.29 for the former compared with 0.45 for the latter. From the factors that were entered in the Tobit model, age of household head, excellent production knowledge and farmer status affected technical efficiency whereas allocative efficiency was only affected by good production knowledge, farm size, arable land owned and area under cultivation. Factors which affected economic efficiency of the resettled farmers are secondary education, household size, farm size, cultivated area and arable land owned. None of the included socio-economic variables has significant effects on the allocative and economic efficiency of the resettled farmers. Thus, the allocative and economic inefficiencies of the farmers might be accounted for by other natural and environmental factors which were not captured in the model.
- Full Text:
- Date Issued: 2011
Desegregation and socio-spatial integration in residential suburbs in East London, South Africa (1993-2008)
- Authors: Bwalya, John
- Date: 2011
- Subjects: City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Geography)
- Identifier: vital:11504 , http://hdl.handle.net/10353/336 , City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Description: This study used integration as the overarching conceptual framework to investigate socio-spatial integration in post-apartheid South Africa. The study adopted the embedded case study design to investigate the spatial and social aspects of integration in former white residential suburbs in East London, South Africa. Recognising that integration occurred in different registers, this study used data from the South African Property Transfer Guide (SAPTG) database to investigate spatial-temporal integration in East London‟s residential suburbs from 1993 to 2008. A total of 21,683 residential property transfers were reviewed in 46 suburbs, and transfers to Blacks were identified. The residential property transfers were mapped to identify the nature of spatial integration. To investigate social integration, in-depth personal interviews were conducted on a purposively drawn sample of residents in the three case study suburbs of Southernwood, Cambridge and Gonubie. The interviews focused on three proxy indicators of social capital at neighbourhood level. The results of the study showed that post-apartheid spatial integration in East London closely followed the class-based residential template. Contrary to predictions prior to, and following apartheid‟s demise, the study showed that spatial integration occurred without racial conflicts. The study also found that social integration in the residential suburbs reflected the neighbourhood context and personal preferences, and was highly fluid. Although feelings of racial distance were evident, there were also indications of social cohesion, which were dynamic and uneven in time and space. Based on the data and the dialectical nature of spatial and social integration, the study concluded that fragmentation and integration are likely to continue coexisting in the South African city.
- Full Text:
- Date Issued: 2011
- Authors: Bwalya, John
- Date: 2011
- Subjects: City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Geography)
- Identifier: vital:11504 , http://hdl.handle.net/10353/336 , City planning -- South Africa -- East London , Apartheid -- South Africa -- Eastern Cape , Migration, Internal -- South Africa -- Eastern Cape
- Description: This study used integration as the overarching conceptual framework to investigate socio-spatial integration in post-apartheid South Africa. The study adopted the embedded case study design to investigate the spatial and social aspects of integration in former white residential suburbs in East London, South Africa. Recognising that integration occurred in different registers, this study used data from the South African Property Transfer Guide (SAPTG) database to investigate spatial-temporal integration in East London‟s residential suburbs from 1993 to 2008. A total of 21,683 residential property transfers were reviewed in 46 suburbs, and transfers to Blacks were identified. The residential property transfers were mapped to identify the nature of spatial integration. To investigate social integration, in-depth personal interviews were conducted on a purposively drawn sample of residents in the three case study suburbs of Southernwood, Cambridge and Gonubie. The interviews focused on three proxy indicators of social capital at neighbourhood level. The results of the study showed that post-apartheid spatial integration in East London closely followed the class-based residential template. Contrary to predictions prior to, and following apartheid‟s demise, the study showed that spatial integration occurred without racial conflicts. The study also found that social integration in the residential suburbs reflected the neighbourhood context and personal preferences, and was highly fluid. Although feelings of racial distance were evident, there were also indications of social cohesion, which were dynamic and uneven in time and space. Based on the data and the dialectical nature of spatial and social integration, the study concluded that fragmentation and integration are likely to continue coexisting in the South African city.
- Full Text:
- Date Issued: 2011
Intellectualisation of African languages with particular reference to isiXhosa
- Authors: Maseko, Pamela
- Date: 2011
- Subjects: Xhosa language -- Study and teaching -- South Africa , Language and education -- South Africa , African languages
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/58035 , vital:27035
- Description: The research explores the relationship between language and education, and motivates for the intellectualisation of African languages, isiXhosa in particular, and for their use in education. The main rationale behind this is that access to, and success in education can largely be realised if that education is mediated in one’s first language. The thesis discusses works of prominent scholars who have written on the subject - relating cognitive abilities and achievement in education to language in which that education is offered. The lack of terminology in new domains in African languages as barrier to mother tongue education is laid bare by looking specifically at the history of intellectualisation of isiXhosa, from the missionaries in the 1820s up to the new endeavours as recently as 2008. Terminologies that were developed during the Bantu Education era, where development of isiXhosa and other indigenous African languages was accelerated in order to respond to the demands of moedertaal-onderwys (mother tongue education) are surveyed, and the process of their development analysed. Three main terminology lists developed during this period are analysed against terminology development principles, approaches and methods that are seen as a measure to ensure quality terminology development. The efforts of the development of isiXhosa during the post-apartheid South Africa, especially the government-driven initiatives, are also critiqued even though these are not as effective and as extensive, especially in education. The result of this analysis is that African languages and isiXhosa in particular, can be used in scientific disciplines and at the highest levels of education. Its grammar is advanced, and its lexicon is extensive such that new concepts that need to be named can be named, using appropriate term creation strategies. There are also technological tools such as WordSmith tools that can be used that can advance its development, ensuring that the concept represented in the newly-created term is precise, concise and appropriate in terms of its discipline. Therefore it is argued that, in the interim, terminologies should be developed, in various subjects, to support learning, which at this stage is mediated in English, for those students who have other languages as mother tongue. Those terminologies that have been developed in the various historical periods should be collated, revised and brought into the classrooms. The thesis argues that real intellectualisation of isiXhosa and other African languages rests on the use of these languages in classrooms and lecture halls, and in the value that all role players place on these languages.
- Full Text:
- Date Issued: 2011
- Authors: Maseko, Pamela
- Date: 2011
- Subjects: Xhosa language -- Study and teaching -- South Africa , Language and education -- South Africa , African languages
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/58035 , vital:27035
- Description: The research explores the relationship between language and education, and motivates for the intellectualisation of African languages, isiXhosa in particular, and for their use in education. The main rationale behind this is that access to, and success in education can largely be realised if that education is mediated in one’s first language. The thesis discusses works of prominent scholars who have written on the subject - relating cognitive abilities and achievement in education to language in which that education is offered. The lack of terminology in new domains in African languages as barrier to mother tongue education is laid bare by looking specifically at the history of intellectualisation of isiXhosa, from the missionaries in the 1820s up to the new endeavours as recently as 2008. Terminologies that were developed during the Bantu Education era, where development of isiXhosa and other indigenous African languages was accelerated in order to respond to the demands of moedertaal-onderwys (mother tongue education) are surveyed, and the process of their development analysed. Three main terminology lists developed during this period are analysed against terminology development principles, approaches and methods that are seen as a measure to ensure quality terminology development. The efforts of the development of isiXhosa during the post-apartheid South Africa, especially the government-driven initiatives, are also critiqued even though these are not as effective and as extensive, especially in education. The result of this analysis is that African languages and isiXhosa in particular, can be used in scientific disciplines and at the highest levels of education. Its grammar is advanced, and its lexicon is extensive such that new concepts that need to be named can be named, using appropriate term creation strategies. There are also technological tools such as WordSmith tools that can be used that can advance its development, ensuring that the concept represented in the newly-created term is precise, concise and appropriate in terms of its discipline. Therefore it is argued that, in the interim, terminologies should be developed, in various subjects, to support learning, which at this stage is mediated in English, for those students who have other languages as mother tongue. Those terminologies that have been developed in the various historical periods should be collated, revised and brought into the classrooms. The thesis argues that real intellectualisation of isiXhosa and other African languages rests on the use of these languages in classrooms and lecture halls, and in the value that all role players place on these languages.
- Full Text:
- Date Issued: 2011