Valuation of internet-based businesses
- Authors: Krüger, Janine
- Date: 2013
- Subjects: Electronic commerce , Internet marketing -- Evaluation , New business enterprises , Internet marketing , Retail trade -- Computer network resources , Teleshopping , Consumer behavior
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9280 , http://hdl.handle.net/10948/d1008187 , Electronic commerce , Internet marketing -- Evaluation , New business enterprises , Internet marketing , Retail trade -- Computer network resources , Teleshopping , Consumer behavior
- Description: This study investigates the valuation of Internet-based businesses. In particular the influence of the implementation of an e-business strategy on the value of a business by focussing on its financial performance, will be determined. Although the valuation of businesses in general has been researched extensively, research on the valuation of Internet-based businesses produced contradictory findings. No consensus could be reached regarding the most appropriate valuation approach to be used. Some research findings indicated that the discounted cash flow approach was the most appropriate while others stipulated that a new valuation approach should be developed. Many authors state that the move to include an e-business strategy is natural, and that businesses cannot afford not to include some form of e-business strategy. Previous research has also shown that by including an e-business strategy, it is possible to improve efficiency of the business and ultimately increase profitability. However, there was no emphasis on how the e-business strategy will influence the business valuation. In order to establish whether an e-business strategy will create value for a business, an empirical investigation was undertaken.
- Full Text:
- Date Issued: 2013
- Authors: Krüger, Janine
- Date: 2013
- Subjects: Electronic commerce , Internet marketing -- Evaluation , New business enterprises , Internet marketing , Retail trade -- Computer network resources , Teleshopping , Consumer behavior
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9280 , http://hdl.handle.net/10948/d1008187 , Electronic commerce , Internet marketing -- Evaluation , New business enterprises , Internet marketing , Retail trade -- Computer network resources , Teleshopping , Consumer behavior
- Description: This study investigates the valuation of Internet-based businesses. In particular the influence of the implementation of an e-business strategy on the value of a business by focussing on its financial performance, will be determined. Although the valuation of businesses in general has been researched extensively, research on the valuation of Internet-based businesses produced contradictory findings. No consensus could be reached regarding the most appropriate valuation approach to be used. Some research findings indicated that the discounted cash flow approach was the most appropriate while others stipulated that a new valuation approach should be developed. Many authors state that the move to include an e-business strategy is natural, and that businesses cannot afford not to include some form of e-business strategy. Previous research has also shown that by including an e-business strategy, it is possible to improve efficiency of the business and ultimately increase profitability. However, there was no emphasis on how the e-business strategy will influence the business valuation. In order to establish whether an e-business strategy will create value for a business, an empirical investigation was undertaken.
- Full Text:
- Date Issued: 2013
Use of bioindicators and biomarkers to assess aquatic environmental contamination in selected urban wetlands in Uganda
- Authors: Naigaga, Irene
- Date: 2013
- Subjects: Indicators (Biology) Biochemical markers Environmental monitoring -- Uganda Water quality biological assessment -- Uganda Water -- Pollution -- Uganda Wetlands -- Monitoring -- Uganda Wetland management -- Uganda Aquatic resources -- Uganda Aquatic resources conservation -- Uganda Aquatic resources -- Management -- Uganda Fishes -- Histopathaology -- Uganda Urban ecology (Biology) -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5198 , http://hdl.handle.net/10962/d1002603
- Description: Pollution of aquatic resources in Uganda is on the increase and the trends are expected to increase with increase in population size and urbanisation. Assessment and mitigation of the environmental impacts on water quality and biodiversity have now become necessary. The aim of the study was to integrate invertebrate and fish as bioindicators and fish histopathology as a biomarker in the assessment of water quality deterioration in urban wetlands in Uganda. The integration harnesses the advantages and counteracts the shortcomings of each method and thus builds a more robust diagnostic tool that gives a better view of the impacts to the entire ecosystem. Four endpoints which included, physicochemical variables, benthic macroinvertebrate bioindicators, fish bioindicators and fish histopathology biomarkers were compared between varied effluent-impacted wetlands (Murchison Bay in Kampala, and Kirinya, Masese and Winday Bay in Jinja) and a non-impacted reference wetland (Lwanika in Mayuge). Results from the effluent-impacted sites differed from the less impacted reference site. The two sampling locations at Murchison Bay (inshore and offshore) and one sampling location at Kirinya (inshore), that were highly impacted with urban effluent, showed elevated nutrient levels, low pH, dissolved oxygen and secchi depth readings. This corresponded with low invertebrate taxa and fish species diversity and richness; and severe histopathological responses in liver, gonads and gills of O. niloticus. Sensitive taxa such as ephemeroptera and trichoptera were completely absent while pollution tolerant taxa Chironomus sp, Corbicula and Oligochaeta were present. Also notable was the absence of many native haplochromines and presence of mainly Brycinus sadleri, Oreochromis niloticus and leucostictus. The organs manifested high prevalence of severe inflammatory and regressive changes and higher organ indices that fell within the pathological category. These sites were consistently classified as highly polluted under the four endpoints. The reference site was classified as least polluted while Masese and Winday Bay were moderately polluted. Results suggested that the approach of using invertebrate and fish as bioindicators and the fish histopathology as a biomarker, in relation to water quality physicochemical variables was a useful tool in highlighting the spatial differences in environmental quality.
- Full Text:
- Date Issued: 2013
- Authors: Naigaga, Irene
- Date: 2013
- Subjects: Indicators (Biology) Biochemical markers Environmental monitoring -- Uganda Water quality biological assessment -- Uganda Water -- Pollution -- Uganda Wetlands -- Monitoring -- Uganda Wetland management -- Uganda Aquatic resources -- Uganda Aquatic resources conservation -- Uganda Aquatic resources -- Management -- Uganda Fishes -- Histopathaology -- Uganda Urban ecology (Biology) -- Uganda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5198 , http://hdl.handle.net/10962/d1002603
- Description: Pollution of aquatic resources in Uganda is on the increase and the trends are expected to increase with increase in population size and urbanisation. Assessment and mitigation of the environmental impacts on water quality and biodiversity have now become necessary. The aim of the study was to integrate invertebrate and fish as bioindicators and fish histopathology as a biomarker in the assessment of water quality deterioration in urban wetlands in Uganda. The integration harnesses the advantages and counteracts the shortcomings of each method and thus builds a more robust diagnostic tool that gives a better view of the impacts to the entire ecosystem. Four endpoints which included, physicochemical variables, benthic macroinvertebrate bioindicators, fish bioindicators and fish histopathology biomarkers were compared between varied effluent-impacted wetlands (Murchison Bay in Kampala, and Kirinya, Masese and Winday Bay in Jinja) and a non-impacted reference wetland (Lwanika in Mayuge). Results from the effluent-impacted sites differed from the less impacted reference site. The two sampling locations at Murchison Bay (inshore and offshore) and one sampling location at Kirinya (inshore), that were highly impacted with urban effluent, showed elevated nutrient levels, low pH, dissolved oxygen and secchi depth readings. This corresponded with low invertebrate taxa and fish species diversity and richness; and severe histopathological responses in liver, gonads and gills of O. niloticus. Sensitive taxa such as ephemeroptera and trichoptera were completely absent while pollution tolerant taxa Chironomus sp, Corbicula and Oligochaeta were present. Also notable was the absence of many native haplochromines and presence of mainly Brycinus sadleri, Oreochromis niloticus and leucostictus. The organs manifested high prevalence of severe inflammatory and regressive changes and higher organ indices that fell within the pathological category. These sites were consistently classified as highly polluted under the four endpoints. The reference site was classified as least polluted while Masese and Winday Bay were moderately polluted. Results suggested that the approach of using invertebrate and fish as bioindicators and the fish histopathology as a biomarker, in relation to water quality physicochemical variables was a useful tool in highlighting the spatial differences in environmental quality.
- Full Text:
- Date Issued: 2013
Understanding current teacher implementation of Zimbabwe's primary school AIDS curriculum: a case study
- Authors: Musingarabwi, Starlin
- Date: 2013
- Subjects: Teacher participation in curriculum planning -- Zimbabwe , Primary school teachers -- Zimbabwe , Education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9584 , http://hdl.handle.net/10948/d1020912
- Description: Zimbabwe’s Ministry of Education Sport, Arts and Culture offers as one of the primary school curricula, an AIDS curriculum which all Grades 4 to 7 teachers in Zimbabwe’s primary schools mandatorily implement with a view to contributing towards the prevention of the spread of HIV/AIDS among the young primary school learners. The purpose of this research was to explore and describe teachers’ understanding and implementation of Zimbabwe’s primary school AIDS curriculum regarding the ways in which they articulated teaching practices and processes in their classrooms. The study also aimed to elicit the teachers’ views on how personal and contextual factors impact their adaptation and enactment of the curriculum. The study also sought to establish teachers’ perceptions of their practical experiences with the implementation of Zimbabwe’s primary school AIDS curriculum and their suggestions for improving practice. The study follows a qualitative case study design with minimal quantitative results. It involved three purposively selected primary school grade six teachers (n=3) each of whom was asked to teach five lessons while being observed over a period of three months. Each teacher availed his or her teaching scheme/plan to the researcher who conducted document analysis to glean their symbolic conceptualisation of actual classroom practice of the curriculum. This was followed by three semi-structured interviews with each participating teacher to elicit their perceptions. A content analysis using ideas borrowed from the grounded theory approach was employed resulting in thematic findings. The findings of the study confirm and enhance the theoretical significance of the phenomenological-adaptive perspective of educational change and Honig’s (people, policy, places) and cognition model for describing teacher implementation of the mandatory AIDS curriculum. The findings also confirm the complex ways in which human-generated personal and contextual factors played out in framing and shaping teachers’ personal adaptation of the mandatory AIDS curriculum. The study confirms the adaptation claim that as cognitive sense-makers, teachers mutate and enact a curriculum according to their personal subjective interpretations in the context of unique use-setting implementation realities. Although one of the participants’ understanding and practice displayed considerable comprehension of the requirements of the curriculum, the other teachers displayed an understanding of this curriculum in a superficial way, and experienced few positive experiences and several conceptual and operational constraints in its implementation. Drawing on their practical experiences with the implementation of the curriculum, teachers offered suggestions for transforming the implementation proficiency of this curriculum, which formed part of the conceptual strategy I developed for improving practice. Thus the resultant achievement of the study was a conceptual strategy that was constructed from the key findings of the study to provide educational change leaders with nuanced ideas and insights for improving practice.
- Full Text:
- Date Issued: 2013
- Authors: Musingarabwi, Starlin
- Date: 2013
- Subjects: Teacher participation in curriculum planning -- Zimbabwe , Primary school teachers -- Zimbabwe , Education -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9584 , http://hdl.handle.net/10948/d1020912
- Description: Zimbabwe’s Ministry of Education Sport, Arts and Culture offers as one of the primary school curricula, an AIDS curriculum which all Grades 4 to 7 teachers in Zimbabwe’s primary schools mandatorily implement with a view to contributing towards the prevention of the spread of HIV/AIDS among the young primary school learners. The purpose of this research was to explore and describe teachers’ understanding and implementation of Zimbabwe’s primary school AIDS curriculum regarding the ways in which they articulated teaching practices and processes in their classrooms. The study also aimed to elicit the teachers’ views on how personal and contextual factors impact their adaptation and enactment of the curriculum. The study also sought to establish teachers’ perceptions of their practical experiences with the implementation of Zimbabwe’s primary school AIDS curriculum and their suggestions for improving practice. The study follows a qualitative case study design with minimal quantitative results. It involved three purposively selected primary school grade six teachers (n=3) each of whom was asked to teach five lessons while being observed over a period of three months. Each teacher availed his or her teaching scheme/plan to the researcher who conducted document analysis to glean their symbolic conceptualisation of actual classroom practice of the curriculum. This was followed by three semi-structured interviews with each participating teacher to elicit their perceptions. A content analysis using ideas borrowed from the grounded theory approach was employed resulting in thematic findings. The findings of the study confirm and enhance the theoretical significance of the phenomenological-adaptive perspective of educational change and Honig’s (people, policy, places) and cognition model for describing teacher implementation of the mandatory AIDS curriculum. The findings also confirm the complex ways in which human-generated personal and contextual factors played out in framing and shaping teachers’ personal adaptation of the mandatory AIDS curriculum. The study confirms the adaptation claim that as cognitive sense-makers, teachers mutate and enact a curriculum according to their personal subjective interpretations in the context of unique use-setting implementation realities. Although one of the participants’ understanding and practice displayed considerable comprehension of the requirements of the curriculum, the other teachers displayed an understanding of this curriculum in a superficial way, and experienced few positive experiences and several conceptual and operational constraints in its implementation. Drawing on their practical experiences with the implementation of the curriculum, teachers offered suggestions for transforming the implementation proficiency of this curriculum, which formed part of the conceptual strategy I developed for improving practice. Thus the resultant achievement of the study was a conceptual strategy that was constructed from the key findings of the study to provide educational change leaders with nuanced ideas and insights for improving practice.
- Full Text:
- Date Issued: 2013
Towards the development of a mycoinsecticide to control white grubs (Coleoptera: Scarabaeidae) in South African sugarcane
- Authors: Goble, Tarryn Anne
- Date: 2013
- Subjects: Insecticides -- Environmental aspects Insecticides -- Toxicology Beetles -- South Africa -- KwaZulu-Natal Beetles -- Control -- South Africa -- KwaZulu-Natal Coleophoridae -- South Africa -- KwaZulu-Natal Scarabaeidae -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- Control -- South Africa -- KwaZulu-Natal , Insecticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5586 , http://hdl.handle.net/10962/d1001748
- Description: In the KwaZulu-Natal (KZN) Midlands North region of South Africa, the importance and increased prevalence of endemic scarabaeids, particularly Hypopholis sommeri Burmeister and Schizonycha affinis Boheman (Coleoptera: Melolonthinae), as soil pests of sugarcane, and a need for their control was established. The development of a mycoinsecticide offers an environmentally friendly alternative to chemical insecticides. The identification of a diversity of white grub species, in two Scarabaeidae subfamilies, representing seven genera were collected in sugarcane as a pest complex. Hypopholis sommeri and S. affinis were the most prevalent species. The increased seasonal abundances, diversity and highly aggregated nature of these scarabaeid species in summer months, suggested that targeting and control strategies for these pests should be considered in this season. Increased rainfall, relative humidity and soil temperatures were linked to the increased occurrence of scarab adults and neonate grubs. Beauveria brongniartii (Saccardo) Petch epizootics were recorded at two sites in the KZN Midlands North on H. sommeri. Seventeen different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria sp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana senso stricto (Balsamo) Vuillemin and B. brongniartii species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear B locus (Bloc) gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. There was no genetic differentiation between the two sites, Harden Heights and Canema in the KZN Midlands North. High gene flow from swarming H. sommeri beetles is the proposed mechanism for this lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal to subterranean habitats in the environment by H. sommeri beetles. This was the first record of this species of fungus causing epizootics on the larvae and adults of H. sommeri in South Africa. The virulence of 21 isolates of Beauveria brongniartii and two isolates of B. bassiana were evaluated against the adults and larvae of S. affinis and the adults of H. sommeri and Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae). Despite being closely-related, B. brongniartii isolates varied significantly in their virulence towards different hosts and highlighted the host specific nature of B. brongniartii towards S. affinis when compared to B. bassiana. Adults of S. affinis were significantly more susceptible to B. brongniartii isolates than the second (L2) or third instar (L3) grubs. The median lethal time (LT₅₀) of the most virulent B. brongniartii isolate (C13) against S. affinis adults was 7.8 days and probit analysis estimated a median lethal concentration (LC₅₀) of 4.4×10⁷ conidia/ml⁻¹. When L2 grubs were treated with a concentration of 1.0×10⁸ conidia/ml⁻¹, B. brongniartii isolates HHWG1, HHB39A and C17 caused mortality in L2 grubs within 18.4-19.8 days (LT₅₀). Beauveria brongniartii isolate HHWG1 was tested against the L3 grubs of S. affinis at four different concentrations. At the lowest concentration (1×10⁶ conidia/ml⁻¹), the LT₅₀ was 25.8 days, and at the highest concentration (1×10⁹ conidia/ml⁻¹) the LT₅₀ dropped to 15.1 days. The persistence of B. bassiana isolate 4222 formulated on rice and wheat bran and buried at eight field sites in the KZN Midlands North was evaluated by plating out a suspension of treated soil onto a selective medium. All eight field sites showed a significant decline in B. bassiana CFUs per gram of soil over time, with few conidia still present in the samples after a year. Greater declines in CFUs were observed at some sites but there were no significant differences observed in the persistence of conidia formulated on rice or wheat bran as carriers. Overall, poor persistence of B. bassiana isolate 4222 was attributed to suboptimum temperatures, rainfall, which rapidly degraded the nutritive carriers, attenuated fungal genotype and the action of antagonistic soil microbes. Growers’ perceptions of white grubs as pests and the feasibility of a mycoinsecticide market were evaluated by means of a semi-structured questionnaire. The study showed that the reduced feasibility of application, general lack of potential demand for a product, high cost factors and most importantly, the lack of pest perception, were factors which would negatively affect the adoption of a granular mycoinsecticide. Growers however exhibited a positive attitude towards mycoinsecticides, and showed all the relevant attributes for successful technology adoption. It is recommended that because B. brongniartii epizootics were recorded on target pests which indicated good host specificity, dispersal ability and persistence of the fungus in the intended environment of application; that a mycoinsecticide based on this fungal species be developed. What will likely increase adoption and success of a mycoinsecticide is collaboration between various industries partners to increases market potential in other crops such as Acacia mearnsii De Wild (Fabales: Fabaceae).
- Full Text:
- Date Issued: 2013
- Authors: Goble, Tarryn Anne
- Date: 2013
- Subjects: Insecticides -- Environmental aspects Insecticides -- Toxicology Beetles -- South Africa -- KwaZulu-Natal Beetles -- Control -- South Africa -- KwaZulu-Natal Coleophoridae -- South Africa -- KwaZulu-Natal Scarabaeidae -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- South Africa -- KwaZulu-Natal Sugarcane -- Diseases and pests -- Control -- South Africa -- KwaZulu-Natal , Insecticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5586 , http://hdl.handle.net/10962/d1001748
- Description: In the KwaZulu-Natal (KZN) Midlands North region of South Africa, the importance and increased prevalence of endemic scarabaeids, particularly Hypopholis sommeri Burmeister and Schizonycha affinis Boheman (Coleoptera: Melolonthinae), as soil pests of sugarcane, and a need for their control was established. The development of a mycoinsecticide offers an environmentally friendly alternative to chemical insecticides. The identification of a diversity of white grub species, in two Scarabaeidae subfamilies, representing seven genera were collected in sugarcane as a pest complex. Hypopholis sommeri and S. affinis were the most prevalent species. The increased seasonal abundances, diversity and highly aggregated nature of these scarabaeid species in summer months, suggested that targeting and control strategies for these pests should be considered in this season. Increased rainfall, relative humidity and soil temperatures were linked to the increased occurrence of scarab adults and neonate grubs. Beauveria brongniartii (Saccardo) Petch epizootics were recorded at two sites in the KZN Midlands North on H. sommeri. Seventeen different fluorescently-labelled microsatellite PCR primers were used to target 78 isolates of Beauveria sp. DNA. Microsatellite data resolved two distinct clusters of Beauveria isolates which represented the Beauveria bassiana senso stricto (Balsamo) Vuillemin and B. brongniartii species groups. These groupings were supported by two gene regions, the nuclear ribosomal Internal Transcribed Spacer (ITS) and the nuclear B locus (Bloc) gene of which 23 exemplar Beauveria isolates were represented and sequenced. When microsatellite data were analysed, 26 haplotypes among 58 isolates of B. brongniartii were distinguished. Relatively low levels of genetic diversity were detected in B. brongniartii and isolates were shown to be closely related. There was no genetic differentiation between the two sites, Harden Heights and Canema in the KZN Midlands North. High gene flow from swarming H. sommeri beetles is the proposed mechanism for this lack of genetic differentiation between populations. Microsatellite analyses also showed that B. brongniartii conidia were being cycled from arboreal to subterranean habitats in the environment by H. sommeri beetles. This was the first record of this species of fungus causing epizootics on the larvae and adults of H. sommeri in South Africa. The virulence of 21 isolates of Beauveria brongniartii and two isolates of B. bassiana were evaluated against the adults and larvae of S. affinis and the adults of H. sommeri and Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae). Despite being closely-related, B. brongniartii isolates varied significantly in their virulence towards different hosts and highlighted the host specific nature of B. brongniartii towards S. affinis when compared to B. bassiana. Adults of S. affinis were significantly more susceptible to B. brongniartii isolates than the second (L2) or third instar (L3) grubs. The median lethal time (LT₅₀) of the most virulent B. brongniartii isolate (C13) against S. affinis adults was 7.8 days and probit analysis estimated a median lethal concentration (LC₅₀) of 4.4×10⁷ conidia/ml⁻¹. When L2 grubs were treated with a concentration of 1.0×10⁸ conidia/ml⁻¹, B. brongniartii isolates HHWG1, HHB39A and C17 caused mortality in L2 grubs within 18.4-19.8 days (LT₅₀). Beauveria brongniartii isolate HHWG1 was tested against the L3 grubs of S. affinis at four different concentrations. At the lowest concentration (1×10⁶ conidia/ml⁻¹), the LT₅₀ was 25.8 days, and at the highest concentration (1×10⁹ conidia/ml⁻¹) the LT₅₀ dropped to 15.1 days. The persistence of B. bassiana isolate 4222 formulated on rice and wheat bran and buried at eight field sites in the KZN Midlands North was evaluated by plating out a suspension of treated soil onto a selective medium. All eight field sites showed a significant decline in B. bassiana CFUs per gram of soil over time, with few conidia still present in the samples after a year. Greater declines in CFUs were observed at some sites but there were no significant differences observed in the persistence of conidia formulated on rice or wheat bran as carriers. Overall, poor persistence of B. bassiana isolate 4222 was attributed to suboptimum temperatures, rainfall, which rapidly degraded the nutritive carriers, attenuated fungal genotype and the action of antagonistic soil microbes. Growers’ perceptions of white grubs as pests and the feasibility of a mycoinsecticide market were evaluated by means of a semi-structured questionnaire. The study showed that the reduced feasibility of application, general lack of potential demand for a product, high cost factors and most importantly, the lack of pest perception, were factors which would negatively affect the adoption of a granular mycoinsecticide. Growers however exhibited a positive attitude towards mycoinsecticides, and showed all the relevant attributes for successful technology adoption. It is recommended that because B. brongniartii epizootics were recorded on target pests which indicated good host specificity, dispersal ability and persistence of the fungus in the intended environment of application; that a mycoinsecticide based on this fungal species be developed. What will likely increase adoption and success of a mycoinsecticide is collaboration between various industries partners to increases market potential in other crops such as Acacia mearnsii De Wild (Fabales: Fabaceae).
- Full Text:
- Date Issued: 2013
Towards a cost-efficient & standardised monitoring protocol for subtidal reef fish in the Agulhas ecoregion of South Africa
- Bernard, Anthony Thomas Firth
- Authors: Bernard, Anthony Thomas Firth
- Date: 2013
- Subjects: Reef fishes -- South Africa Reef fishes -- Monitoring--South Africa Fish stock assessment -- South Africa Coastal zone management -- South Africa Fish communities -- South Africa Marine parks and reserves -- South Africa Marine resources conservation -- South Africa Marine biodiversity conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5585 , http://hdl.handle.net/10962/d1001674
- Description: Under the growing demand for marine fish resources, and the apparent and expected impacts of global climate change, there is a need to conduct long-term monitoring (LTM) to ensure effective management of resources and conservation of biodiversity. However LTM programmes often suffer from design deficiencies and fail to achieve their objectives. These deficiencies stem from the fact that insufficient consideration is afforded to the design phase, with programmes selecting methods that are not suitable to address the objectives, or are not cost-efficient, compromising the sustainability of the LTM. To facilitate the establishment of LTM programmes along the southern coast of South Africa, background research needed to be conducted to identify which methods were most appropriate for LTM of reef fish. This study presents a detailed field-based assessment of the suitability and cost-efficiency of monitoring methods for long-term monitoring of reef fish in the Agulhas Ecoregion of South Africa. The approach adopted to identify the method, or suite of methods most suited for LTM, involved (i) the selection of methods considered suitable for LTM, (ii) the individual assessment and optimisation of method performance, and (iii) the comparative assessment of the fish community sampled by the different methods. The most suited method(s) were then identified as those that provide the most comprehensive assessment of the fish community and had the highest cost-efficiency. The research was conducted between January 2008 and 2011 in the Tsitsikamma and Table Mountain National Park (TNP and TMNP, respectively) marine protected areas (MPAs) within the Agulhas Ecoregion. The methods selected included fish traps (FT), controlled angling (CA), underwater visual census (UVC), remote underwater video (RUV), baited RUV (BRUV) and remotely operated vehicles (ROV). The individual assessment and optimisation was conducted with the FT, UVC, RUV and BRUV methods. The assessment of the FT method aimed to identify the optimal soak time, and whether or not the size of the funnel entrance to the trap affected the catch. The results identified that larger funnel entrances caught more fish and soak times of 80 minutes produced the highest catches per unit effort. However the data were highly variable and the method detected few of the species typical of the region. Fish traps were also associated with high levels of mortality of fish post-release. The assessment of UVC strip transect method involved directly comparing the precision of data collected by researchers and volunteers using a novel double-observer technique (paired-transects). The results showed considerable error in both the volunteers and researchers data, however the researchers produced significantly higher precision data, compared to the volunteers. The distinction between researchers and volunteers was not evident in the data for the dominant species of fish. For all observers, the abundance of a species in the sample had a significant influence on its detectability, with locally scarce or rare species poorly detected. UVC was able to sample the majority of species typical of reefs in the region, however it appeared plagued by observer and detectability biases. The assessments of RUV and BRUV were conducted simultaneously which enabled the assessment of the effect of bait on the observed fish community. In addition the optimal deployment time for both methods to maximise species richness and abundance was determined. The results showed that BRUV, and to a lesser degree RUV, were able to effectively survey the reef fish community for the region with a 50 minute and 35 minute deployment time, respectively. Baited remote underwater video was especially good at detecting the invertebrate and generalist carnivores, and cartilaginous species. On the other hand, RUV was more effective at surveying the microinvertebrate carnivores. Remote underwater video was characterised by higher data variability, compared to BRUV, and was ultimately considered a less cost-efficient monitoring method. Comparative methods assessments were conducted during two field experiments with the FT, UVC and BRUV methods in the TMNP MPA, and the FT, CA, UVC, RUV, BRUV and ROV methods compared in the TNP MPA. The objectives of the comparison were to investigate differences in the fish communities observed with the different methods, and to determine the power of the data to detect an annual 10% growth in the fish populations over a period of five years. The results from the method comparison were in turn used to conduct the cost-benefit analysis to determine the efficiency of the different methods at achieving monitoring objectives requiring population data from multiple trophic and functional groups with the community, and from species of fisheries importance. The results indicated that FT, CA and ROV were ineffective at monitoring the reef fish community, although CA appeared to provide valuable data for the dominant fisheries species. Both CA and FT required minimal initial investment however, the variability in the data translated into high annual monitoring costs, as the required sampling effort was great. The ROV required the highest initial investment and was identified as the least cost-efficient method. Underwater visual census was able to adequately survey the bony fish within the community, however it did not detect the cartilaginous species. Underwater visual census required a large initial investment and was not cost-efficient, as a many samples were required to account for the variability in the data. Remote underwater video provided a comprehensive assessment of the reef fish community, however it too was associated with high levels of variability in the data, compared to BRUV, reducing its cost-efficiency. BRUV provided the most comprehensive assessment of the reef fish community and was associated with the highest cost-efficiency to address the community and fisheries species monitoring objectives. During the course of this research stereo-BRUV has gained considerable support as an effective reef fish monitoring method. Although not tested during this research, stereo-BRUV is preferred to BRUV as it provides accurate data on the size of fish. However, the initial investment of stereo-BRUV is over three times that required for the BRUV. Although it is recommended that a baited video technique be used for LTM in the Agulhas Ecoregion, the choice between BRUV and stereo-BRUV will depend on the specific objectives of the programme and the available budget at the implementing agency.
- Full Text:
- Date Issued: 2013
- Authors: Bernard, Anthony Thomas Firth
- Date: 2013
- Subjects: Reef fishes -- South Africa Reef fishes -- Monitoring--South Africa Fish stock assessment -- South Africa Coastal zone management -- South Africa Fish communities -- South Africa Marine parks and reserves -- South Africa Marine resources conservation -- South Africa Marine biodiversity conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5585 , http://hdl.handle.net/10962/d1001674
- Description: Under the growing demand for marine fish resources, and the apparent and expected impacts of global climate change, there is a need to conduct long-term monitoring (LTM) to ensure effective management of resources and conservation of biodiversity. However LTM programmes often suffer from design deficiencies and fail to achieve their objectives. These deficiencies stem from the fact that insufficient consideration is afforded to the design phase, with programmes selecting methods that are not suitable to address the objectives, or are not cost-efficient, compromising the sustainability of the LTM. To facilitate the establishment of LTM programmes along the southern coast of South Africa, background research needed to be conducted to identify which methods were most appropriate for LTM of reef fish. This study presents a detailed field-based assessment of the suitability and cost-efficiency of monitoring methods for long-term monitoring of reef fish in the Agulhas Ecoregion of South Africa. The approach adopted to identify the method, or suite of methods most suited for LTM, involved (i) the selection of methods considered suitable for LTM, (ii) the individual assessment and optimisation of method performance, and (iii) the comparative assessment of the fish community sampled by the different methods. The most suited method(s) were then identified as those that provide the most comprehensive assessment of the fish community and had the highest cost-efficiency. The research was conducted between January 2008 and 2011 in the Tsitsikamma and Table Mountain National Park (TNP and TMNP, respectively) marine protected areas (MPAs) within the Agulhas Ecoregion. The methods selected included fish traps (FT), controlled angling (CA), underwater visual census (UVC), remote underwater video (RUV), baited RUV (BRUV) and remotely operated vehicles (ROV). The individual assessment and optimisation was conducted with the FT, UVC, RUV and BRUV methods. The assessment of the FT method aimed to identify the optimal soak time, and whether or not the size of the funnel entrance to the trap affected the catch. The results identified that larger funnel entrances caught more fish and soak times of 80 minutes produced the highest catches per unit effort. However the data were highly variable and the method detected few of the species typical of the region. Fish traps were also associated with high levels of mortality of fish post-release. The assessment of UVC strip transect method involved directly comparing the precision of data collected by researchers and volunteers using a novel double-observer technique (paired-transects). The results showed considerable error in both the volunteers and researchers data, however the researchers produced significantly higher precision data, compared to the volunteers. The distinction between researchers and volunteers was not evident in the data for the dominant species of fish. For all observers, the abundance of a species in the sample had a significant influence on its detectability, with locally scarce or rare species poorly detected. UVC was able to sample the majority of species typical of reefs in the region, however it appeared plagued by observer and detectability biases. The assessments of RUV and BRUV were conducted simultaneously which enabled the assessment of the effect of bait on the observed fish community. In addition the optimal deployment time for both methods to maximise species richness and abundance was determined. The results showed that BRUV, and to a lesser degree RUV, were able to effectively survey the reef fish community for the region with a 50 minute and 35 minute deployment time, respectively. Baited remote underwater video was especially good at detecting the invertebrate and generalist carnivores, and cartilaginous species. On the other hand, RUV was more effective at surveying the microinvertebrate carnivores. Remote underwater video was characterised by higher data variability, compared to BRUV, and was ultimately considered a less cost-efficient monitoring method. Comparative methods assessments were conducted during two field experiments with the FT, UVC and BRUV methods in the TMNP MPA, and the FT, CA, UVC, RUV, BRUV and ROV methods compared in the TNP MPA. The objectives of the comparison were to investigate differences in the fish communities observed with the different methods, and to determine the power of the data to detect an annual 10% growth in the fish populations over a period of five years. The results from the method comparison were in turn used to conduct the cost-benefit analysis to determine the efficiency of the different methods at achieving monitoring objectives requiring population data from multiple trophic and functional groups with the community, and from species of fisheries importance. The results indicated that FT, CA and ROV were ineffective at monitoring the reef fish community, although CA appeared to provide valuable data for the dominant fisheries species. Both CA and FT required minimal initial investment however, the variability in the data translated into high annual monitoring costs, as the required sampling effort was great. The ROV required the highest initial investment and was identified as the least cost-efficient method. Underwater visual census was able to adequately survey the bony fish within the community, however it did not detect the cartilaginous species. Underwater visual census required a large initial investment and was not cost-efficient, as a many samples were required to account for the variability in the data. Remote underwater video provided a comprehensive assessment of the reef fish community, however it too was associated with high levels of variability in the data, compared to BRUV, reducing its cost-efficiency. BRUV provided the most comprehensive assessment of the reef fish community and was associated with the highest cost-efficiency to address the community and fisheries species monitoring objectives. During the course of this research stereo-BRUV has gained considerable support as an effective reef fish monitoring method. Although not tested during this research, stereo-BRUV is preferred to BRUV as it provides accurate data on the size of fish. However, the initial investment of stereo-BRUV is over three times that required for the BRUV. Although it is recommended that a baited video technique be used for LTM in the Agulhas Ecoregion, the choice between BRUV and stereo-BRUV will depend on the specific objectives of the programme and the available budget at the implementing agency.
- Full Text:
- Date Issued: 2013
The use of Geographical Information Systems for the promotion of spatial cognition, spatial perspective taking and problem solving in school level geography
- Authors: Britz, Hendrina Wilhemina
- Date: 2013
- Subjects: Geography -- Study and teaching -- South Africa -- Port Elizabeth , Geographic information systems -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9579 , http://hdl.handle.net/10948/d1020298
- Description: A question asked at the United States of America (USA) National Council for Geographic Education (NCGE) conference in 1967, namely, what learning does GIS allow that other ways do not and whether teaching GIS at school level is worth the time and effort required to implement it, remains largely unanswered. Literature searches suggest that little more has been done since 1967 to investigate the effectiveness of GIS in education, or that there are any findings to suggest that GIS is worth the time and effort to implement in schools. Internationally the implementation of GIS software and geo-spatial data in schools has been slow, and South Africa is no exception. The main reasons given for slow implementation internationally have included lack of resources, lack of training and lack of time. The majority of secondary schools that offer Geography in the Port Elizabeth Education District, South Africa, teach GIS theory without the use of GIS software and geo-spatial data. The purpose of this research was to elicit the perceptions of secondary school level Geography teachers and learners of the benefits, barriers and obstacles to implementing GIS software and geo-spatial data as a teaching strategy. As a focused exercise to investigate what learning using GIS allows that other ways do not, this study also investigated whether using GIS as a teaching and learning strategy enables the promotion of learners spatial cognition, spatial perspective taking and problem solving abilities better than traditional methods do. The findings are viewed through the lens of developing Crystallized Intelligence (Gc), Spatial Intelligence (Gv) and Fluid Intelligence (Gf), respectively. The study followed a concurrent transformative mixed methods design with pre-post testing and the use of crossover experimental and control groups to generate both qualitative and quantitative data. Questionnaires aimed at all secondary Geography teachers in the Port Elizabeth Education District were used to assess how GIS is taught in their schools and to evaluate their perceptions of the benefits and barriers of implementing GIS software and geo-spatial data in the classroom. Four secondary school Geography teachers in four schools volunteered to take part in the experimental aspects of the study. Empirical data on the development of spatial cognition, spatial perspective taking, and problem solving were generated via pre- and post-tests in which the grade 11 Geography learners participated. Experimental and comparison groups of learners wrote four different types of pre- and post-tests where the experimental groups worked on GIS software with geo-spatial data while the comparison groups used traditional methods. Teacher interviews and learner interviews were also conducted to assess attitudes towards GIS software and geo-spatial data as a teaching strategy. The results from this aspect of the study mirrored the benefits and barriers to implementing GIS in schools recorded in international literature. However, and possibly more importantly, the empirical data generated by the learners revealed that GIS software and geo-spatial data do statistically significantly promote better spatial cognition (Crystallized Intelligence) and spatial perspective taking (Spatial Intelligence) than traditional methods do (i.e. using atlases, rulers and calculators). No improvement was found in the experimental groups‟ problem solving abilities. This report offers possible explanations and recommendations in terms of socio-cultural findings from other educational studies on the effects of exploratory talk on the development of Fluid Intelligence. Recommendations are made for the attention of curriculum developers, teachers, school principals, departmental officials and other educational stakeholders in terms of what is required for the successful implementation of GIS software and the use of geo-spatial data in secondary school Geography classes.
- Full Text:
- Date Issued: 2013
- Authors: Britz, Hendrina Wilhemina
- Date: 2013
- Subjects: Geography -- Study and teaching -- South Africa -- Port Elizabeth , Geographic information systems -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9579 , http://hdl.handle.net/10948/d1020298
- Description: A question asked at the United States of America (USA) National Council for Geographic Education (NCGE) conference in 1967, namely, what learning does GIS allow that other ways do not and whether teaching GIS at school level is worth the time and effort required to implement it, remains largely unanswered. Literature searches suggest that little more has been done since 1967 to investigate the effectiveness of GIS in education, or that there are any findings to suggest that GIS is worth the time and effort to implement in schools. Internationally the implementation of GIS software and geo-spatial data in schools has been slow, and South Africa is no exception. The main reasons given for slow implementation internationally have included lack of resources, lack of training and lack of time. The majority of secondary schools that offer Geography in the Port Elizabeth Education District, South Africa, teach GIS theory without the use of GIS software and geo-spatial data. The purpose of this research was to elicit the perceptions of secondary school level Geography teachers and learners of the benefits, barriers and obstacles to implementing GIS software and geo-spatial data as a teaching strategy. As a focused exercise to investigate what learning using GIS allows that other ways do not, this study also investigated whether using GIS as a teaching and learning strategy enables the promotion of learners spatial cognition, spatial perspective taking and problem solving abilities better than traditional methods do. The findings are viewed through the lens of developing Crystallized Intelligence (Gc), Spatial Intelligence (Gv) and Fluid Intelligence (Gf), respectively. The study followed a concurrent transformative mixed methods design with pre-post testing and the use of crossover experimental and control groups to generate both qualitative and quantitative data. Questionnaires aimed at all secondary Geography teachers in the Port Elizabeth Education District were used to assess how GIS is taught in their schools and to evaluate their perceptions of the benefits and barriers of implementing GIS software and geo-spatial data in the classroom. Four secondary school Geography teachers in four schools volunteered to take part in the experimental aspects of the study. Empirical data on the development of spatial cognition, spatial perspective taking, and problem solving were generated via pre- and post-tests in which the grade 11 Geography learners participated. Experimental and comparison groups of learners wrote four different types of pre- and post-tests where the experimental groups worked on GIS software with geo-spatial data while the comparison groups used traditional methods. Teacher interviews and learner interviews were also conducted to assess attitudes towards GIS software and geo-spatial data as a teaching strategy. The results from this aspect of the study mirrored the benefits and barriers to implementing GIS in schools recorded in international literature. However, and possibly more importantly, the empirical data generated by the learners revealed that GIS software and geo-spatial data do statistically significantly promote better spatial cognition (Crystallized Intelligence) and spatial perspective taking (Spatial Intelligence) than traditional methods do (i.e. using atlases, rulers and calculators). No improvement was found in the experimental groups‟ problem solving abilities. This report offers possible explanations and recommendations in terms of socio-cultural findings from other educational studies on the effects of exploratory talk on the development of Fluid Intelligence. Recommendations are made for the attention of curriculum developers, teachers, school principals, departmental officials and other educational stakeholders in terms of what is required for the successful implementation of GIS software and the use of geo-spatial data in secondary school Geography classes.
- Full Text:
- Date Issued: 2013
The SKA's the limit : on the nature of faint radio sources
- Authors: McAlpine, Kim
- Date: 2013 , 2012-09-14
- Subjects: Radio telescopes -- South Africa Radio astronomy -- South Africa Square Kilometer Array (Spacecraft)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5504 , http://hdl.handle.net/10962/d1007271
- Description: From abstract: Within the next few years a large number of new and vastly more sensitive radio astronomy facilities are scheduled to come online. These new facilities will map large areas of the sky to unprecedented depths and transform radio astronomy into the leading technique for investigating the complex processes which govern the formation and evolution of galaxies. This thesis combines multi-wavelength techniques, highly relevant to future deep radio surveys, to study the evolution and properties of faint radio sources. , TeX , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: McAlpine, Kim
- Date: 2013 , 2012-09-14
- Subjects: Radio telescopes -- South Africa Radio astronomy -- South Africa Square Kilometer Array (Spacecraft)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5504 , http://hdl.handle.net/10962/d1007271
- Description: From abstract: Within the next few years a large number of new and vastly more sensitive radio astronomy facilities are scheduled to come online. These new facilities will map large areas of the sky to unprecedented depths and transform radio astronomy into the leading technique for investigating the complex processes which govern the formation and evolution of galaxies. This thesis combines multi-wavelength techniques, highly relevant to future deep radio surveys, to study the evolution and properties of faint radio sources. , TeX , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
The screening and characterisation of compounds for modulators of heat shock protein (Hsp90) in a breast cancer cell model
- Authors: Moyo, Buhle
- Date: 2013 , 2013-07-18
- Subjects: Heat shock proteins Breast -- Cancer Breast -- Cancer -- Chemotherapy Breast -- Cancer -- Treatment Cancer cells Naphthoquinone PQQ (Biochemistry)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4060 , http://hdl.handle.net/10962/d1004129
- Description: Breast cancer is a leading cause of cancer death in Africa. Hsp90 has been identified as a target for anti-cancer treatments as its inhibition results in the disruption and ubiquitin–proteasome degradation of activated oncoproteins. Currently, there are no US Food and Drug Administration approved Hsp90 inhibitor drugs and existing Hsp90 inhibitors such as geldanamycin and novobiocin are hepatotoxic and display a low affinity for Hsp90, respectively. Therefore, there is a need for the development of Hsp90 inhibitors with improved inhibitory properties. In this study twelve natural compounds bearing a quinone nucleus were screened and characterised for the modulation of Hsp90. The compounds analysed formed three series; the sargaquinoic acid (SQA), naphthoquinone, and pyrroloiminoquinone alkaloid series. Certain compounds exhibited half maximal inhibitory concentrations of between 3.32 μM and 12.4 μM, while others showed no antiproliferative activity at concentrations of up to 500 μM in the MDA-MB-231 breast adenocarcinoma cell line. Immunofluorescence and Western analyses indicated that the modulation of Hsp90 and partner proteins by SQA was more similar to that of novobiocin. Isothermal titration calorimetry analyses suggested that SQA interacted with Hsp90β with a low affinity, and saturation-transfer difference nuclear magnetic resonance confirmed that this interaction with Hsp90β occurred through the methyl moiety bound to 1, 4 benzoquinone of SQA. Pulldown assays indicated SQA disrupted the association between Hsp90 and Hop dose-dependently, more similarly to novobiocin. Immunofluorescence and Western analyses performed on naphthoquinone and pyrroloiminoquinone alkaloid compounds indicated modulation of Hsp90 and Hsp90 partner proteins by the compounds. Naphthoquinone compounds were prioritised for analysis for binding to Hsp90β over the pyrroloiminoquinone alkaloid compounds. Lapachol interacted with Hsp90β with a low affinity however; this interaction was thought to be too weak to disrupt the association of Hsp90 and Hop. The remaining naphthoquinone compounds showed no interaction with Hsp90β, thus allowing the determination of a preliminary structure-activity relationship for these compounds. To the best of our knowledge, this is the first study to describe a systematic subcellular analysis of the effects of geldanamycin and novobiocin in comparison to sargaquinoic acid and compounds of the naphthoquinone and pyrroloquinoline scaffold on Hsp90 and its partner proteins. , Microsoft� Word 2010 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Moyo, Buhle
- Date: 2013 , 2013-07-18
- Subjects: Heat shock proteins Breast -- Cancer Breast -- Cancer -- Chemotherapy Breast -- Cancer -- Treatment Cancer cells Naphthoquinone PQQ (Biochemistry)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4060 , http://hdl.handle.net/10962/d1004129
- Description: Breast cancer is a leading cause of cancer death in Africa. Hsp90 has been identified as a target for anti-cancer treatments as its inhibition results in the disruption and ubiquitin–proteasome degradation of activated oncoproteins. Currently, there are no US Food and Drug Administration approved Hsp90 inhibitor drugs and existing Hsp90 inhibitors such as geldanamycin and novobiocin are hepatotoxic and display a low affinity for Hsp90, respectively. Therefore, there is a need for the development of Hsp90 inhibitors with improved inhibitory properties. In this study twelve natural compounds bearing a quinone nucleus were screened and characterised for the modulation of Hsp90. The compounds analysed formed three series; the sargaquinoic acid (SQA), naphthoquinone, and pyrroloiminoquinone alkaloid series. Certain compounds exhibited half maximal inhibitory concentrations of between 3.32 μM and 12.4 μM, while others showed no antiproliferative activity at concentrations of up to 500 μM in the MDA-MB-231 breast adenocarcinoma cell line. Immunofluorescence and Western analyses indicated that the modulation of Hsp90 and partner proteins by SQA was more similar to that of novobiocin. Isothermal titration calorimetry analyses suggested that SQA interacted with Hsp90β with a low affinity, and saturation-transfer difference nuclear magnetic resonance confirmed that this interaction with Hsp90β occurred through the methyl moiety bound to 1, 4 benzoquinone of SQA. Pulldown assays indicated SQA disrupted the association between Hsp90 and Hop dose-dependently, more similarly to novobiocin. Immunofluorescence and Western analyses performed on naphthoquinone and pyrroloiminoquinone alkaloid compounds indicated modulation of Hsp90 and Hsp90 partner proteins by the compounds. Naphthoquinone compounds were prioritised for analysis for binding to Hsp90β over the pyrroloiminoquinone alkaloid compounds. Lapachol interacted with Hsp90β with a low affinity however; this interaction was thought to be too weak to disrupt the association of Hsp90 and Hop. The remaining naphthoquinone compounds showed no interaction with Hsp90β, thus allowing the determination of a preliminary structure-activity relationship for these compounds. To the best of our knowledge, this is the first study to describe a systematic subcellular analysis of the effects of geldanamycin and novobiocin in comparison to sargaquinoic acid and compounds of the naphthoquinone and pyrroloquinoline scaffold on Hsp90 and its partner proteins. , Microsoft� Word 2010 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
The role of conflict management in maintenance of discipline : the case of Kenya's public secondary schools
- Authors: Kibui, Agnes Wanja
- Date: 2013
- Subjects: School discipline -- Kenya , Discipline of children -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:16151 , http://hdl.handle.net/10948/d1020074
- Description: This study set out to establish the role of conflict Management in Maintenance of Discipline in Kenya’s Public Secondary Schools. The study formulated 6 objectives as follows: examine the nature of Conflict experienced in Public Secondary Schools in Kenya; establish how teachers and students perceive conflict in secondary schools; determine how teachers and students experience conflict in Secondary Schools; investigate the effectiveness of conflict Management Programmes used in Secondary Schools; discover suitable conflict management programmes to address present and future conflict in secondary schools; generate findings based on a theoretical approach for understanding and managing conflict in secondary schools with particular reference to schools in Kenya. The research was conducted in the form of a descriptive survey design with a mixed methods approach which combined qualitative research design and quantitative research technique. A sample of 649 Students, 16 secondary school head teachers, and 16 secondary school guidance and counseling officers from 4 provinces in Kenya was used to obtain data for the study. Random and purposive sampling techniques were used. Data was collected using questionnaires and structured interviews. Descriptive statistics such as mean, percentages, standard deviation, and frequencies was used to discuss the research findings. The study also used inferential statistics, particularly chi-square to test the significant statistical differences on the nature of conflict in schools, how students and teachers experience and perceive conflict in different categories of schools. From the findings, students witness conflict in form of theft, 51.7%, bullying, 29 percent, rumours and fights. Results from males and females indicate that drugs are abused in secondary schools (males (26.8%) and females (13.6 percent). All the respondents revealed that students take drugs to please their peers, and to release stress, and for adventure. On the effectiveness of conflict management programmes, a majority of students accept punishment when they break the school rules (80.0%) as they feel that punishments improve their behaviour. Most of the teachers had not had proper training in conflict management and some of them do not understand the role of peer mediation as they lack such programmes in their schools. The study concluded that failure to train teachers in conflict management skills, and to involve students in decision making causes conflict in schools. The study recommended that life skills, and peace keeping lessons should be taught in schools. In addition, head teachers and teachers should go for a refresher course in conflict management. Also, the study recommends that a comparative study should be done in a wider scope in secondary schools that experience conflict and those that do not, so as to get an insight of the suitable strategies needed to manage conflict in schools.
- Full Text:
- Date Issued: 2013
- Authors: Kibui, Agnes Wanja
- Date: 2013
- Subjects: School discipline -- Kenya , Discipline of children -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:16151 , http://hdl.handle.net/10948/d1020074
- Description: This study set out to establish the role of conflict Management in Maintenance of Discipline in Kenya’s Public Secondary Schools. The study formulated 6 objectives as follows: examine the nature of Conflict experienced in Public Secondary Schools in Kenya; establish how teachers and students perceive conflict in secondary schools; determine how teachers and students experience conflict in Secondary Schools; investigate the effectiveness of conflict Management Programmes used in Secondary Schools; discover suitable conflict management programmes to address present and future conflict in secondary schools; generate findings based on a theoretical approach for understanding and managing conflict in secondary schools with particular reference to schools in Kenya. The research was conducted in the form of a descriptive survey design with a mixed methods approach which combined qualitative research design and quantitative research technique. A sample of 649 Students, 16 secondary school head teachers, and 16 secondary school guidance and counseling officers from 4 provinces in Kenya was used to obtain data for the study. Random and purposive sampling techniques were used. Data was collected using questionnaires and structured interviews. Descriptive statistics such as mean, percentages, standard deviation, and frequencies was used to discuss the research findings. The study also used inferential statistics, particularly chi-square to test the significant statistical differences on the nature of conflict in schools, how students and teachers experience and perceive conflict in different categories of schools. From the findings, students witness conflict in form of theft, 51.7%, bullying, 29 percent, rumours and fights. Results from males and females indicate that drugs are abused in secondary schools (males (26.8%) and females (13.6 percent). All the respondents revealed that students take drugs to please their peers, and to release stress, and for adventure. On the effectiveness of conflict management programmes, a majority of students accept punishment when they break the school rules (80.0%) as they feel that punishments improve their behaviour. Most of the teachers had not had proper training in conflict management and some of them do not understand the role of peer mediation as they lack such programmes in their schools. The study concluded that failure to train teachers in conflict management skills, and to involve students in decision making causes conflict in schools. The study recommended that life skills, and peace keeping lessons should be taught in schools. In addition, head teachers and teachers should go for a refresher course in conflict management. Also, the study recommends that a comparative study should be done in a wider scope in secondary schools that experience conflict and those that do not, so as to get an insight of the suitable strategies needed to manage conflict in schools.
- Full Text:
- Date Issued: 2013
The restoration of an alien-invaded riparian zone in grassy fynbos, South Africa
- Authors: Fourie, Saskia
- Date: 2013
- Subjects: Fynbos ecology -- South Africa Riparian ecology -- South Africa Riparian restoration -- South Africa Alien plants -- South Africa Invasive plants -- South Africa Endemic plants -- South Africa Plants -- Effect of fires on -- South Africa Soil seed banks -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4733 , http://hdl.handle.net/10962/d1003840
- Description: The most recent surveys in South Africa estimate that invasions are still increasing, despite substantial clearing efforts. Riparian systems in South Africa are particularly vulnerable to invasion by woody IAPs. This thesis addresses the restoration of alien‐invaded riparian systems, by investigating the factors that facilitate or constrain spontaneous recovery and influence the trajectories of succession. These factors include invasion history and management history, especially the use of fire. A seedling emergence approach was used to test the presence of a viable pre‐fire seedbank, and the effect of fire on the seed bank. The efficacy of some active restoration interventions was also tested, with the aim to return invasion‐resistant, indigenous vegetation with a structure and function representative of uninvaded sites. The findings of this study indicated the presence of a viable and persistent riparian soil seed bank, even after 30 years of intermtittent invasion as well as two fire cycles under invasion. It shows that the management practice of fell‐and‐burn resulted in high soil temperatures, and that this reduced the indigenous soil seed bank density, especially in the upper soil layer. Clear germination sequences and patterns of emergence over time for different species were observed during this study, with many species exhibiting delayed emergence relative to the timing of the fire event. It is proposed that manipulation of the season of fire could be used to selectively optimise the order of arrival and therefore superior recruitment of some species over others in the Eastern Cape fynbos, and thus alter the trajectories of recovery of vegetation towards a more desired state. Active restoration in the form of indigenous seed and plant additions resulted in a significantly higher indigenous cover after seven months, compared to a control (passive restoration) or restoring with grass. Indigenous cover and composition was also strongly influenced by lateral zonation, and some key guilds and species were missing or present in much lower densities compared to reference sites. Grass restoration significantly suppressed the regeneration of A. longifolia, as well as the regeneration of indigenous species. Biotic resistance can thus be achieved through restoration, and it could be a powerful tool in the management of IAPs, although the deliberate introduction of grass after clearing in fynbos also reduces biodiversity and could have unforeseen consequences to riparian function.
- Full Text:
- Date Issued: 2013
- Authors: Fourie, Saskia
- Date: 2013
- Subjects: Fynbos ecology -- South Africa Riparian ecology -- South Africa Riparian restoration -- South Africa Alien plants -- South Africa Invasive plants -- South Africa Endemic plants -- South Africa Plants -- Effect of fires on -- South Africa Soil seed banks -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4733 , http://hdl.handle.net/10962/d1003840
- Description: The most recent surveys in South Africa estimate that invasions are still increasing, despite substantial clearing efforts. Riparian systems in South Africa are particularly vulnerable to invasion by woody IAPs. This thesis addresses the restoration of alien‐invaded riparian systems, by investigating the factors that facilitate or constrain spontaneous recovery and influence the trajectories of succession. These factors include invasion history and management history, especially the use of fire. A seedling emergence approach was used to test the presence of a viable pre‐fire seedbank, and the effect of fire on the seed bank. The efficacy of some active restoration interventions was also tested, with the aim to return invasion‐resistant, indigenous vegetation with a structure and function representative of uninvaded sites. The findings of this study indicated the presence of a viable and persistent riparian soil seed bank, even after 30 years of intermtittent invasion as well as two fire cycles under invasion. It shows that the management practice of fell‐and‐burn resulted in high soil temperatures, and that this reduced the indigenous soil seed bank density, especially in the upper soil layer. Clear germination sequences and patterns of emergence over time for different species were observed during this study, with many species exhibiting delayed emergence relative to the timing of the fire event. It is proposed that manipulation of the season of fire could be used to selectively optimise the order of arrival and therefore superior recruitment of some species over others in the Eastern Cape fynbos, and thus alter the trajectories of recovery of vegetation towards a more desired state. Active restoration in the form of indigenous seed and plant additions resulted in a significantly higher indigenous cover after seven months, compared to a control (passive restoration) or restoring with grass. Indigenous cover and composition was also strongly influenced by lateral zonation, and some key guilds and species were missing or present in much lower densities compared to reference sites. Grass restoration significantly suppressed the regeneration of A. longifolia, as well as the regeneration of indigenous species. Biotic resistance can thus be achieved through restoration, and it could be a powerful tool in the management of IAPs, although the deliberate introduction of grass after clearing in fynbos also reduces biodiversity and could have unforeseen consequences to riparian function.
- Full Text:
- Date Issued: 2013
The influence of overwash and breaching events on the spatial and temporal patterns in ichthyofauna community composition in a temporarily open/closed southern African estuary
- Authors: Tweddle, Gavin Paul
- Date: 2013
- Subjects: Estuarine fishes -- Africa, Southern Marine fishes -- Africa, Southern Fishes -- Breeding -- Africa, Southern Fishes -- Effect of habitat modification on -- Africa, Southern Fishes -- Spawning -- Africa, Southern Gobiidae -- Africa, Southern Estuaries -- Africa, Southern Estuarine ecology -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5610 , http://hdl.handle.net/10962/d1002957
- Description: This study assessed the importance of overwash and breaching events on the ichthyofaunal community structure in the medium-sized temporarily open/closed Mpekweni Estuary located on the southeast coastline of southern Africa. The fish in the littoral zone of the estuary were sampled using a 5m seine net while the channel region was sampled using two nets, a smaller meshed 30m seine net to target the estuarine spawning species and the juvenile estuarine-dependant marine spawners, and a larger meshed 50m seine net to target the larger marine and freshwater spawning species. Intensive monthly sampling over two years provided data on selected physico-chemical and biological parameters. During the two year sampling period from November 2005 to October 2007 the estuary breached in late July 2006 and remained open till the sandbar re-formed across the mouth in late December 2006. Thus, sampling encompassed three open/closed phases 1) initial closed period, 2) open period and 3) re-closed period after the berm was re-formed. The open period was divided into two phases 1) the out-flow phase and 2) the tidal phase. A total of 36 fish species representing 19 families were sampled using the various seine nets employed during the investigation. In the littoral zone, the estuarine spawners (Estuarine Utilisation Category, [EUC] I), mainly the Gobiidae, Glossogobius callidus, dominated the samples numerically and by biomass. The smaller estuarine spawning species sampled in the channel were numerically dominated by Gilchristella aestuaria in conjunction with two other EUC I species, Atherina breviceps and G. callidus. The estuarine-dependant marine spawners (EUC II), however, dominated the ichthyofaunal biomass of the channel. The abundance and biomass of the larger species targeted were dominated by estuarine-dependant marine spawning species (EUC II), principally Rhabdosargus holubi. During the closed periods of the estuary, total fish abundance and biomass displayed weak seasonal patterns. The breaching event and subsequent open period was associated with a decrease in the total abundances of fish in the littoral zone and channel of the estuary, reflecting the out-flow of estuarine biomass-rich water into the marine environment. The breaching event coincided with a shift in the community composition of the ichthyofauna, reflecting the recruitment of marine spawning species into the estuary. Numerical analysis identified two distinct spatial fish communities within the estuary, a community associated with the mouth region and one comprising the rest of the estuary. The absence of any further spatial patterns in the ichthyofaunal community structure within the Mpekweni Estuary appear to be ascribed to the virtual absence of horizontal patterns in physico-chemical and biological parameters recorded in the system. Cohort analyses were employed to determine possible recruitment events for selected estuarine and marine spawning species. The estuarine spawning species displayed continuous recruitment patterns throughout the study, which appeared to be unaffected by the breaching event. Conversely, the larger marine spawning species displayed multiple cohorts, indicating non-continuous recruitment. Subsequent retrospective analysis of cohorts for the different species identified summer recruitment peaks that coincided with the breaching event and open period. Minor recruitment of marine spawning species also occurred during overwash events. The recruitment of ichthyofauna into the estuary was quantified during three distinct hydrological events: overwash, out-flow phase immediately after breaching and tidal phase during the period when the mouth was open. Estimates of fish recruitment were highest during the outflow phase immediately after the estuary breached and declined as the estuary became tidally inundated with marine water. Although not as high as the outflow and tidal phases, recruitment was evident during overwash events. Results of the current study highlight the importance of both breaching and overwashing events in structuring the ichthyofaunal community composition in a medium-sized southern African temporarily open/closed estuary. These results are broadly in agreement with similar studies conducted both locally and in other regions of the world.
- Full Text:
- Date Issued: 2013
- Authors: Tweddle, Gavin Paul
- Date: 2013
- Subjects: Estuarine fishes -- Africa, Southern Marine fishes -- Africa, Southern Fishes -- Breeding -- Africa, Southern Fishes -- Effect of habitat modification on -- Africa, Southern Fishes -- Spawning -- Africa, Southern Gobiidae -- Africa, Southern Estuaries -- Africa, Southern Estuarine ecology -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5610 , http://hdl.handle.net/10962/d1002957
- Description: This study assessed the importance of overwash and breaching events on the ichthyofaunal community structure in the medium-sized temporarily open/closed Mpekweni Estuary located on the southeast coastline of southern Africa. The fish in the littoral zone of the estuary were sampled using a 5m seine net while the channel region was sampled using two nets, a smaller meshed 30m seine net to target the estuarine spawning species and the juvenile estuarine-dependant marine spawners, and a larger meshed 50m seine net to target the larger marine and freshwater spawning species. Intensive monthly sampling over two years provided data on selected physico-chemical and biological parameters. During the two year sampling period from November 2005 to October 2007 the estuary breached in late July 2006 and remained open till the sandbar re-formed across the mouth in late December 2006. Thus, sampling encompassed three open/closed phases 1) initial closed period, 2) open period and 3) re-closed period after the berm was re-formed. The open period was divided into two phases 1) the out-flow phase and 2) the tidal phase. A total of 36 fish species representing 19 families were sampled using the various seine nets employed during the investigation. In the littoral zone, the estuarine spawners (Estuarine Utilisation Category, [EUC] I), mainly the Gobiidae, Glossogobius callidus, dominated the samples numerically and by biomass. The smaller estuarine spawning species sampled in the channel were numerically dominated by Gilchristella aestuaria in conjunction with two other EUC I species, Atherina breviceps and G. callidus. The estuarine-dependant marine spawners (EUC II), however, dominated the ichthyofaunal biomass of the channel. The abundance and biomass of the larger species targeted were dominated by estuarine-dependant marine spawning species (EUC II), principally Rhabdosargus holubi. During the closed periods of the estuary, total fish abundance and biomass displayed weak seasonal patterns. The breaching event and subsequent open period was associated with a decrease in the total abundances of fish in the littoral zone and channel of the estuary, reflecting the out-flow of estuarine biomass-rich water into the marine environment. The breaching event coincided with a shift in the community composition of the ichthyofauna, reflecting the recruitment of marine spawning species into the estuary. Numerical analysis identified two distinct spatial fish communities within the estuary, a community associated with the mouth region and one comprising the rest of the estuary. The absence of any further spatial patterns in the ichthyofaunal community structure within the Mpekweni Estuary appear to be ascribed to the virtual absence of horizontal patterns in physico-chemical and biological parameters recorded in the system. Cohort analyses were employed to determine possible recruitment events for selected estuarine and marine spawning species. The estuarine spawning species displayed continuous recruitment patterns throughout the study, which appeared to be unaffected by the breaching event. Conversely, the larger marine spawning species displayed multiple cohorts, indicating non-continuous recruitment. Subsequent retrospective analysis of cohorts for the different species identified summer recruitment peaks that coincided with the breaching event and open period. Minor recruitment of marine spawning species also occurred during overwash events. The recruitment of ichthyofauna into the estuary was quantified during three distinct hydrological events: overwash, out-flow phase immediately after breaching and tidal phase during the period when the mouth was open. Estimates of fish recruitment were highest during the outflow phase immediately after the estuary breached and declined as the estuary became tidally inundated with marine water. Although not as high as the outflow and tidal phases, recruitment was evident during overwash events. Results of the current study highlight the importance of both breaching and overwashing events in structuring the ichthyofaunal community composition in a medium-sized southern African temporarily open/closed estuary. These results are broadly in agreement with similar studies conducted both locally and in other regions of the world.
- Full Text:
- Date Issued: 2013
The impact and control of waterweeds in the Southern Mozambique Basin rivers
- Authors: Langa, Sílvia da Fátima
- Date: 2013
- Subjects: Water hyacinth -- Mozambique Water ferns -- Mozambique Water lettuce -- Mozambique Salvinia molesta -- Mozambique Aquatic weeds -- Mozambique Invasive plants -- Mozambique Aquatic weeds -- Control -- Mozambique Invasive plants -- Control -- Mozambique Aquatic weeds -- Biological control -- Mozambique Invasive plants -- Biological control -- Mozambique Aquatic resources -- Management -- Mozambique Beetles -- Mozambique Insects as biological pest control agents -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5587 , http://hdl.handle.net/10962/d1001905
- Description: In Mozambique, establishment of aquatic weeds has been enhanced through the increased enrichment of water bodies by nutrient runoffs from human and agricultural wastes that lead to an increase in nitrate and phosphate in the water. The aquatic weeds, water hyacinth (Eichhornia crassipes), red water fern ( Azolla microphylla), water lettuce (Pistia stratiotes) and salvinia (Salvinia molesta) were found in most watercourses in Mozambique and are becoming aggressive in some watercourses, especially in the Umbeluzi and Incomati rivers. Farmers and people living along the rivers are aware of the negative impact of the water weeds because the large mats of weeds cause loss of shoreline and navigability along the rivers. Other commonly perceived effects of aquatic invasive plants in Mozambique rivers include: reduced navigable surface area; difficulties for fishermen, which reduces income; increased prevalence of insects and insect-borne disease, and decreased aesthetic value. The methods currently used for the control and management of the aquatic weeds are mechanical and manual control. Both methods are costly, time consuming, and only provide a short-term solution to the problem. The study found that the weevils Neochetina eichhorniae and N. bruchi were effective biological control agents in the study area but their impact is too gradual compared to the aggressive proliferation of water hyacinth. The one year lab-experiment clearly demonstrated that the water lettuce weed had a significant impact on the recruitment of macro-invertebrates to the artificial substrates, and water lettuce contributed to the reduction of oxygen in the water and consequent reduction of macro-invertebrate abundance and diversity. The biodiversity recovered at the same time in the pools containing water lettuce controlled by N. affinis and water lettuce controlled by herbicide, but richness and diversity of macro-invertebrates was higher in the water lettuce controlled by N affinis during the first sampling occasion compared to the water lettuce in pools controlled by herbicide, where macro-invertebrates increased only when DO levels recovered after water lettuce mat decay. The number of taxa recorded in this study is an indication of the significance of macro-invertebrates in an aquatic environment. This therefore emphasizes the need for more research efforts into macrophyte and macro-invertebrate associations in the aquatic system to better understand the implications of habitat modification arising from human activities. It will also enable us to be better equipped with a more appropriate ecological understanding for aquatic resources management.
- Full Text:
- Date Issued: 2013
- Authors: Langa, Sílvia da Fátima
- Date: 2013
- Subjects: Water hyacinth -- Mozambique Water ferns -- Mozambique Water lettuce -- Mozambique Salvinia molesta -- Mozambique Aquatic weeds -- Mozambique Invasive plants -- Mozambique Aquatic weeds -- Control -- Mozambique Invasive plants -- Control -- Mozambique Aquatic weeds -- Biological control -- Mozambique Invasive plants -- Biological control -- Mozambique Aquatic resources -- Management -- Mozambique Beetles -- Mozambique Insects as biological pest control agents -- Mozambique
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5587 , http://hdl.handle.net/10962/d1001905
- Description: In Mozambique, establishment of aquatic weeds has been enhanced through the increased enrichment of water bodies by nutrient runoffs from human and agricultural wastes that lead to an increase in nitrate and phosphate in the water. The aquatic weeds, water hyacinth (Eichhornia crassipes), red water fern ( Azolla microphylla), water lettuce (Pistia stratiotes) and salvinia (Salvinia molesta) were found in most watercourses in Mozambique and are becoming aggressive in some watercourses, especially in the Umbeluzi and Incomati rivers. Farmers and people living along the rivers are aware of the negative impact of the water weeds because the large mats of weeds cause loss of shoreline and navigability along the rivers. Other commonly perceived effects of aquatic invasive plants in Mozambique rivers include: reduced navigable surface area; difficulties for fishermen, which reduces income; increased prevalence of insects and insect-borne disease, and decreased aesthetic value. The methods currently used for the control and management of the aquatic weeds are mechanical and manual control. Both methods are costly, time consuming, and only provide a short-term solution to the problem. The study found that the weevils Neochetina eichhorniae and N. bruchi were effective biological control agents in the study area but their impact is too gradual compared to the aggressive proliferation of water hyacinth. The one year lab-experiment clearly demonstrated that the water lettuce weed had a significant impact on the recruitment of macro-invertebrates to the artificial substrates, and water lettuce contributed to the reduction of oxygen in the water and consequent reduction of macro-invertebrate abundance and diversity. The biodiversity recovered at the same time in the pools containing water lettuce controlled by N. affinis and water lettuce controlled by herbicide, but richness and diversity of macro-invertebrates was higher in the water lettuce controlled by N affinis during the first sampling occasion compared to the water lettuce in pools controlled by herbicide, where macro-invertebrates increased only when DO levels recovered after water lettuce mat decay. The number of taxa recorded in this study is an indication of the significance of macro-invertebrates in an aquatic environment. This therefore emphasizes the need for more research efforts into macrophyte and macro-invertebrate associations in the aquatic system to better understand the implications of habitat modification arising from human activities. It will also enable us to be better equipped with a more appropriate ecological understanding for aquatic resources management.
- Full Text:
- Date Issued: 2013
The ecology and management of the large carnivore guild on Shamwari Game Reserve, Eastern Cape
- Authors: O'Brien, John William
- Date: 2013
- Subjects: Cheetah -- Behavior -- South Africa -- Shamwari Game Reserve Shamwari Game Reserve (South Africa) Carnivora -- South Africa -- Shamwari Game Reserve Wildlife conservation -- South Africa -- Shamwari Game Reserve Game reserves -- Management -- South Africa -- Shamwari Game Reserve Lion -- Behavior -- South Africa -- Shamwari Game Reserve Lion -- Ecology -- South Africa -- Shamwari Game Reserve African wild dog -- Ecology -- South Africa -- Shamwari Game Reserve Cheetah -- Ecology -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Cheetah -- Food -- South Africa -- Shamwari Game Reserve African wild dog -- Behavior -- South Africa -- Shamwari Game Reserve African wild dog -- Food -- South Africa -- Shamwari Game Reserve Leopard -- Behavior -- South Africa -- Shamwari Game Reserve Leopard -- Ecology -- South Africa -- Shamwari Game Reserve Leopard -- Food --South Africa -- Shamwari Game Reserve
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5609 , http://hdl.handle.net/10962/d1002604
- Description: Shamwari Game Reserve was the first enclosed conservation area in the Eastern Cape Province of South Africa to reintroduce free ranging lions, cheetahs, leopards and wild dogs back into their historic range. At that time (2000 – 2001), little information was available on the ecology and behaviour of these predators in the habitats of the Eastern Cape, and management decisions were based on assumptions and unfounded comparisons with extant populations but from quite different habitats. The aim of this study was therefore to obtain a better understanding of the feeding ecology and space use of the predator guild, and the carrying capacity of Shamwari Game Reserve to enable more informed management decisions. In addition, the reserve is a photographic based tourism venture and understanding both the ecological and financial sustainability of the predator guild was important. The diets of the predators were similar to those reported in other studies; larger predators killed a greater range of prey species than did smaller predators and a small number of prey species made up the majority of the kills. The larger predators had a higher mean kill mass than the smaller species and prey selection was influenced by prey size, prey abundance and prey habitat preference, and risk associated with hunting the species. Diet was flexible and responded to natural and management induced changes in prey abundance. There was a considerable overlap in space use by the lions, cheetahs and leopards with their core areas being centred on and around the Bushmans River. Space use was driven by resource distribution and landscape attributes, and by the presence of other predators of the same or different species. The long term viability of wild dog within the reserve was explored and the results confirmed that there was neither the required space nor the ecological processes and the wild dogs were removed from the reserve. A carrying capacity of the reserve for the predator guild was determined using the Maximum Sustainable Yield method to assess the potential prey species off take and a resultant density of 3.3 to 6.6 lion female equivalent units per 10 000 ha was established. The natural carrying capacity of the reserve with respect to predators will not sustain the tourism objectives and consequently prey supplementation was necessary to maintain predator density at levels high enough to sustain tourism. Under these conditions the large predator guild is still sustainable financially although careful, responsible management is needed to provide ecological sustainability.
- Full Text:
- Date Issued: 2013
- Authors: O'Brien, John William
- Date: 2013
- Subjects: Cheetah -- Behavior -- South Africa -- Shamwari Game Reserve Shamwari Game Reserve (South Africa) Carnivora -- South Africa -- Shamwari Game Reserve Wildlife conservation -- South Africa -- Shamwari Game Reserve Game reserves -- Management -- South Africa -- Shamwari Game Reserve Lion -- Behavior -- South Africa -- Shamwari Game Reserve Lion -- Ecology -- South Africa -- Shamwari Game Reserve African wild dog -- Ecology -- South Africa -- Shamwari Game Reserve Cheetah -- Ecology -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Lion -- Food -- South Africa -- Shamwari Game Reserve Cheetah -- Food -- South Africa -- Shamwari Game Reserve African wild dog -- Behavior -- South Africa -- Shamwari Game Reserve African wild dog -- Food -- South Africa -- Shamwari Game Reserve Leopard -- Behavior -- South Africa -- Shamwari Game Reserve Leopard -- Ecology -- South Africa -- Shamwari Game Reserve Leopard -- Food --South Africa -- Shamwari Game Reserve
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5609 , http://hdl.handle.net/10962/d1002604
- Description: Shamwari Game Reserve was the first enclosed conservation area in the Eastern Cape Province of South Africa to reintroduce free ranging lions, cheetahs, leopards and wild dogs back into their historic range. At that time (2000 – 2001), little information was available on the ecology and behaviour of these predators in the habitats of the Eastern Cape, and management decisions were based on assumptions and unfounded comparisons with extant populations but from quite different habitats. The aim of this study was therefore to obtain a better understanding of the feeding ecology and space use of the predator guild, and the carrying capacity of Shamwari Game Reserve to enable more informed management decisions. In addition, the reserve is a photographic based tourism venture and understanding both the ecological and financial sustainability of the predator guild was important. The diets of the predators were similar to those reported in other studies; larger predators killed a greater range of prey species than did smaller predators and a small number of prey species made up the majority of the kills. The larger predators had a higher mean kill mass than the smaller species and prey selection was influenced by prey size, prey abundance and prey habitat preference, and risk associated with hunting the species. Diet was flexible and responded to natural and management induced changes in prey abundance. There was a considerable overlap in space use by the lions, cheetahs and leopards with their core areas being centred on and around the Bushmans River. Space use was driven by resource distribution and landscape attributes, and by the presence of other predators of the same or different species. The long term viability of wild dog within the reserve was explored and the results confirmed that there was neither the required space nor the ecological processes and the wild dogs were removed from the reserve. A carrying capacity of the reserve for the predator guild was determined using the Maximum Sustainable Yield method to assess the potential prey species off take and a resultant density of 3.3 to 6.6 lion female equivalent units per 10 000 ha was established. The natural carrying capacity of the reserve with respect to predators will not sustain the tourism objectives and consequently prey supplementation was necessary to maintain predator density at levels high enough to sustain tourism. Under these conditions the large predator guild is still sustainable financially although careful, responsible management is needed to provide ecological sustainability.
- Full Text:
- Date Issued: 2013
The contribution of submerged macrophytes and macroalgae to nutrient cycling in the Great Brak Estuary
- Authors: Human, Lucienne Ryno Daniel
- Date: 2013
- Subjects: Nutrient cycles -- South Africa -- Great Brak Estuary , Microalgae -- South Africa -- Great Brak Estuary , Estuarine ecology -- South Africa -- Great Brak Estuary
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10364 , http://hdl.handle.net/10948/d1021102
- Description: An ecological reserve study by the Department of Water Affairs on the Great Brak Estuary stated that there was a need to determine how much nitrogen and phosphorus was flowing through the estuary as well as how effective the macroalgae were at removing N and P. The objective of this study was to investigate the physico-chemical characteristics in the estuary and the influence of these on the submerged macrophytes and macroalgae. A nutrient budget for the estuary was developed in order to quantify the contribution of the submerged macrophytes and macroalgae relative to other contributing sources. The Wolwedans Dam located 3 km upstream from the estuary has reduced the amount of freshwater flow to the estuary by as much as 56 percent. The estuary has been allocated 2 x 106 m3 per annum of freshwater (ecological reserve) that is used to breach the mouth once or twice a year in spring or summer. Even though this water has been made available it is not sufficient to flush the estuary. Reduced flushing has led to an accumulation of organic matter and degradation in the water quality. Physico-chemical measurements between September 2010 and July 2012 showed that dissolved oxygen values were generally below 6 mg l-1. The average NH4+ concentration in the estuary was 7 μM and increased with depth to 12 μM at 2 m depths. Concentrations >45 μM were found in February and April 2011 at the 5 m deep hole at 3.4 km upstream. Negative correlations between dissolved oxygen and NH4+ during November 2010, February 2011, April 2011 and July 2011 (r = -0.68; -0.67; -0.63; -0.96) indicated that remineralisation of organic matter had occurred. Soluble reactive phosphorus (SRP) followed a similar trend to the NH4+ and was generally below 1 μM in the water column for most months, and had peaks at 1.0 km and 3.4 km in the bottom water. The abundance of submerged macrophytes and macroalgae below the N2 bridge were mostly influenced by mouth state and river inflow. During the closed phase the dominant macroalga Cladophora glomerata had an area cover ranging from 3000 to 6000 m2 while Zostera capensis and Ruppia cirrhosa covered an area of 2000 to 3500 m2 and 1500 to 2900 m2, respectively. After an artificial breach in February 2011, water drained out of the estuary leaving the alga stranded on the marshes and as the flood tide entered the macroalga was once again redistributed in the lower reaches. The alga utilised the available nutrients in the water column and expanded its area cover from 35000 m2 in February 2011 to 64000 m2 in March 2011. However, after the floods in June 2011, Cladophora glomerata had been washed out of the system while the submerged macrophytes responded positively extending their area cover. By comparing the artificial breach with the natural breach, and the effect on the estuary, an important observation was highlighted. Increasing the current allocated ecological reserve, and using a larger volume of water to breach the mouth artificially, would result in better scouring of sediment and associated organic matter out of the estuary. This would enable better oxygenation of the water column, reduce remineralisation and minimise algal blooms.
- Full Text:
- Date Issued: 2013
- Authors: Human, Lucienne Ryno Daniel
- Date: 2013
- Subjects: Nutrient cycles -- South Africa -- Great Brak Estuary , Microalgae -- South Africa -- Great Brak Estuary , Estuarine ecology -- South Africa -- Great Brak Estuary
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10364 , http://hdl.handle.net/10948/d1021102
- Description: An ecological reserve study by the Department of Water Affairs on the Great Brak Estuary stated that there was a need to determine how much nitrogen and phosphorus was flowing through the estuary as well as how effective the macroalgae were at removing N and P. The objective of this study was to investigate the physico-chemical characteristics in the estuary and the influence of these on the submerged macrophytes and macroalgae. A nutrient budget for the estuary was developed in order to quantify the contribution of the submerged macrophytes and macroalgae relative to other contributing sources. The Wolwedans Dam located 3 km upstream from the estuary has reduced the amount of freshwater flow to the estuary by as much as 56 percent. The estuary has been allocated 2 x 106 m3 per annum of freshwater (ecological reserve) that is used to breach the mouth once or twice a year in spring or summer. Even though this water has been made available it is not sufficient to flush the estuary. Reduced flushing has led to an accumulation of organic matter and degradation in the water quality. Physico-chemical measurements between September 2010 and July 2012 showed that dissolved oxygen values were generally below 6 mg l-1. The average NH4+ concentration in the estuary was 7 μM and increased with depth to 12 μM at 2 m depths. Concentrations >45 μM were found in February and April 2011 at the 5 m deep hole at 3.4 km upstream. Negative correlations between dissolved oxygen and NH4+ during November 2010, February 2011, April 2011 and July 2011 (r = -0.68; -0.67; -0.63; -0.96) indicated that remineralisation of organic matter had occurred. Soluble reactive phosphorus (SRP) followed a similar trend to the NH4+ and was generally below 1 μM in the water column for most months, and had peaks at 1.0 km and 3.4 km in the bottom water. The abundance of submerged macrophytes and macroalgae below the N2 bridge were mostly influenced by mouth state and river inflow. During the closed phase the dominant macroalga Cladophora glomerata had an area cover ranging from 3000 to 6000 m2 while Zostera capensis and Ruppia cirrhosa covered an area of 2000 to 3500 m2 and 1500 to 2900 m2, respectively. After an artificial breach in February 2011, water drained out of the estuary leaving the alga stranded on the marshes and as the flood tide entered the macroalga was once again redistributed in the lower reaches. The alga utilised the available nutrients in the water column and expanded its area cover from 35000 m2 in February 2011 to 64000 m2 in March 2011. However, after the floods in June 2011, Cladophora glomerata had been washed out of the system while the submerged macrophytes responded positively extending their area cover. By comparing the artificial breach with the natural breach, and the effect on the estuary, an important observation was highlighted. Increasing the current allocated ecological reserve, and using a larger volume of water to breach the mouth artificially, would result in better scouring of sediment and associated organic matter out of the estuary. This would enable better oxygenation of the water column, reduce remineralisation and minimise algal blooms.
- Full Text:
- Date Issued: 2013
The application of the Rome Statute of the International Criminal Court to illegal natural resource exploitation in the Congo conflic
- Authors: Tsabora, James
- Date: 2013 , 2013-03-27
- Subjects: International criminal law -- Congo (Democratic Republic) Criminal procedure (International law) Natural resources -- Law and legislation -- Congo (Democratic Republic)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3665 , http://hdl.handle.net/10962/d1002612
- Description: This thesis explores the phenomenon of illegal natural resource exploitation in conflict zones and the application of international criminal law, particularly the Rome Statute of the International Criminal Court to combat the roblem. Contemporary African conflicts, such as the Democratic Republic of Congo conflict explored as a case study herein, have become increasingly distinguishable by the tight connection between war and various forms of illegal natural resource exploitation, particularly targeting valuable and precious mineral resources. With their incidence being highest in Africa, wars funded by illegally exploited natural resources have gradually become one of the greatest threats to regional peace and human security on the African continent. The Congo conflict clearly demonstrated the problematic nature and impact of illegal natural resource exploitation and the widespread human, economic and political costs associated with this phenomenon. This thesis is based on the initial assumption that the quest by conflict actors to profit from war through illegal natural resource exploitation activities is at the centre of the commission of serious human rights violations as well as the complexity and longevity of African conflicts. Developments in international criminal law, culminating in the adoption of the Rome Statute and the establishment of the International Criminal Court, have given impetus to the argument that any group of conflict actors should be subjected to the individual criminal responsibility regime of this legal framework. A further underlying assumption of this thesis is therefore that international criminal law can constrain the acts and conduct defined in this thesis as illegal natural resource exploitation activities since they constitute war crimes under the Rome Statute framework. However, despite illustrating the illegal resource exploitation activities of various state and non-state actors, this thesis is confined to an application of the Rome Statute based international criminal liability regime against members of armed rebel groups involved in such acts. In exploring these issues, this work examines international criminal law institutions and the relevance of international criminal justice in addressing particular phenomena prevalent during African armed conflicts. It further provides the stage to assess the potential of international criminal law in safeguarding natural resources for the benefit of African societies perennially exposed to the depredations of natural resource financed warfare. , Microsoft� Office Word 2007 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
- Authors: Tsabora, James
- Date: 2013 , 2013-03-27
- Subjects: International criminal law -- Congo (Democratic Republic) Criminal procedure (International law) Natural resources -- Law and legislation -- Congo (Democratic Republic)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3665 , http://hdl.handle.net/10962/d1002612
- Description: This thesis explores the phenomenon of illegal natural resource exploitation in conflict zones and the application of international criminal law, particularly the Rome Statute of the International Criminal Court to combat the roblem. Contemporary African conflicts, such as the Democratic Republic of Congo conflict explored as a case study herein, have become increasingly distinguishable by the tight connection between war and various forms of illegal natural resource exploitation, particularly targeting valuable and precious mineral resources. With their incidence being highest in Africa, wars funded by illegally exploited natural resources have gradually become one of the greatest threats to regional peace and human security on the African continent. The Congo conflict clearly demonstrated the problematic nature and impact of illegal natural resource exploitation and the widespread human, economic and political costs associated with this phenomenon. This thesis is based on the initial assumption that the quest by conflict actors to profit from war through illegal natural resource exploitation activities is at the centre of the commission of serious human rights violations as well as the complexity and longevity of African conflicts. Developments in international criminal law, culminating in the adoption of the Rome Statute and the establishment of the International Criminal Court, have given impetus to the argument that any group of conflict actors should be subjected to the individual criminal responsibility regime of this legal framework. A further underlying assumption of this thesis is therefore that international criminal law can constrain the acts and conduct defined in this thesis as illegal natural resource exploitation activities since they constitute war crimes under the Rome Statute framework. However, despite illustrating the illegal resource exploitation activities of various state and non-state actors, this thesis is confined to an application of the Rome Statute based international criminal liability regime against members of armed rebel groups involved in such acts. In exploring these issues, this work examines international criminal law institutions and the relevance of international criminal justice in addressing particular phenomena prevalent during African armed conflicts. It further provides the stage to assess the potential of international criminal law in safeguarding natural resources for the benefit of African societies perennially exposed to the depredations of natural resource financed warfare. , Microsoft� Office Word 2007 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Date Issued: 2013
The adaptation of the 'Clinical Outcomes in Routine Evaluation-Outcome Measure' (CORE-OM) from English into a valid Xhosa measure of distress
- Authors: Campbell, Megan Michelle
- Date: 2013 , 2013-06-06
- Subjects: Psychometrics -- Research -- South Africa Psychology -- Mathematical models -- Research -- South Africa Psychological tests -- Research -- South Africa Mental health services -- Research -- South Africa Health services accessibility -- Research -- South Africa Language disorders -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2894 , http://hdl.handle.net/10962/d1001538
- Description: In South Africa access to mental healthcare resources is restricted for a number of reasons including language barriers that prevent suitable communication between mental healthcare professionals and African language speaking South Africans. The translation of psychometric tools into African languages has been identified as one method in improving access to psychological services for African language speakers. The Clinical Outcomes in Routine Evaluation - Outcome Measure (CORE-OM) has demonstrated its clinical utility within the United Kingdom (UK) National Healthcare Service (NHS) as a standardised psychotherapy outcome measure that evaluates the degree of psychological distress individuals present with at the start of psychotherapy treatment, and the degree of change that has been effected at the termination of therapy. A measure like the CORE-OM holds valuable clinical utility for the South African context. This thesis argues that the availability of a valid Xhosa version of the CORE-OM would allow for improved access to psychotherapy resources for Xhosa speaking individuals, and allow for the evaluation of the effectiveness of psychotherapy interventions conducted in Xhosa. The CORE-OM developers have provided a translation design and set of guidelines to standardise the translation of the CORE-OM into different languages. However this thesis argues that these guidelines are incomplete. Instead International Test Commission (ITC) guidelines are recommended as a culturally sensitive method to supplement current CORE-OM translation guidelines, in order to generate a valid Xhosa measure of distress. A mixed methods approach is applied which first investigates the construct equivalence and bias of the CORE-OM English version within a South African student population sample, both qualitatively and quantitatively, in order to establish the degree of adaptation required to generate a valid Xhosa version of distress. Next the CORE-OM English version is translated into Xhosa using the five-stage translation design prescribed by the CORE System Trust, supplemented by ITC guidelines. All changes made to the CORE-OM during translation into Xhosa are documented. The CORE-OM Xhosa version is then investigated for reliability and validity. This investigation reveals low internal reliability within the subjective wellbeing domain indicating that these items are less meaningful as depictions of distress within the Xhosa language. A reduced version of the CORE-OM demonstrates strong psychometric properties as a valid Xhosa measure of distress.
- Full Text:
- Date Issued: 2013
- Authors: Campbell, Megan Michelle
- Date: 2013 , 2013-06-06
- Subjects: Psychometrics -- Research -- South Africa Psychology -- Mathematical models -- Research -- South Africa Psychological tests -- Research -- South Africa Mental health services -- Research -- South Africa Health services accessibility -- Research -- South Africa Language disorders -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2894 , http://hdl.handle.net/10962/d1001538
- Description: In South Africa access to mental healthcare resources is restricted for a number of reasons including language barriers that prevent suitable communication between mental healthcare professionals and African language speaking South Africans. The translation of psychometric tools into African languages has been identified as one method in improving access to psychological services for African language speakers. The Clinical Outcomes in Routine Evaluation - Outcome Measure (CORE-OM) has demonstrated its clinical utility within the United Kingdom (UK) National Healthcare Service (NHS) as a standardised psychotherapy outcome measure that evaluates the degree of psychological distress individuals present with at the start of psychotherapy treatment, and the degree of change that has been effected at the termination of therapy. A measure like the CORE-OM holds valuable clinical utility for the South African context. This thesis argues that the availability of a valid Xhosa version of the CORE-OM would allow for improved access to psychotherapy resources for Xhosa speaking individuals, and allow for the evaluation of the effectiveness of psychotherapy interventions conducted in Xhosa. The CORE-OM developers have provided a translation design and set of guidelines to standardise the translation of the CORE-OM into different languages. However this thesis argues that these guidelines are incomplete. Instead International Test Commission (ITC) guidelines are recommended as a culturally sensitive method to supplement current CORE-OM translation guidelines, in order to generate a valid Xhosa measure of distress. A mixed methods approach is applied which first investigates the construct equivalence and bias of the CORE-OM English version within a South African student population sample, both qualitatively and quantitatively, in order to establish the degree of adaptation required to generate a valid Xhosa version of distress. Next the CORE-OM English version is translated into Xhosa using the five-stage translation design prescribed by the CORE System Trust, supplemented by ITC guidelines. All changes made to the CORE-OM during translation into Xhosa are documented. The CORE-OM Xhosa version is then investigated for reliability and validity. This investigation reveals low internal reliability within the subjective wellbeing domain indicating that these items are less meaningful as depictions of distress within the Xhosa language. A reduced version of the CORE-OM demonstrates strong psychometric properties as a valid Xhosa measure of distress.
- Full Text:
- Date Issued: 2013
Synthesis, characterisation and biological activity of 2-(methylthiomethyl)anilines, 2-(methylthio)anilines, their Schiff-base derivatives and metal(II) (Co, Ni, Cu) complexes
- Olalekan, Temitope Elizabeth
- Authors: Olalekan, Temitope Elizabeth
- Date: 2013
- Subjects: Aniline , Schiff bases , Ligands , Nuclear magnetic resonance spectroscopy , Chelates , X-ray crystallography , Antimalarials
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4562 , http://hdl.handle.net/10962/d1020868
- Description: A series of 31 sulfur-nitrogen donor ligands and 64 metal(II) complexes have been investigated. The thiomethylated aniline ligands 2–(methylthiomethyl)aniline 2MT and 2–(methylthio)aniline 2MA were synthesized with their substituted derivatives (-Me, -MeO, -Cl, -Br, -NO2) to serve as chelating agents. These ligands behave as bidentate ligands with SN donor group with Co(II), Ni(II) and Cu(II). The Co(II) and Ni(II) complexes have the ML2Cl2 molecular formula while the Cu(II) complexes formed with MLCl2 stoichiometry where L is the bidentate ligand. The ligands and their metal(II) complexes have been characterized by elemental analysis and with spectroscopic techniques. The trend observed in the NMR spectra and IR frequencies of the thiomethylated compounds shows there is a significant difference between the 2MT and 2MA series as a result of sulfur lone pairs extending the conjugation of the aromatic ring in the case of the latter. The effect of the position and electronic nature of ring substituent on the NMR shifts of the amine protons is discussed. The 6- and 5-membered chelate complexes formed by the 2MT and 2MA ligands respectively do not show significant diversity in their spectroscopic properties. From the elemental analysis for the Co(II) and Ni(II) complexes, their compositions reveal 1:2 M:L stoichiometry with 2 chlorine atoms from the respective metal salts. In addition, the spectroscopic data are largely indicative of tetragonally distorted structures for these solid complexes. The X-ray crystallography data reveal the Cu(II) complexes exist as square pyramidal dimers and with long Cu–Cl equitorial bonds fit into the tetragonally distorted octahedral structure. The electrolytic nature of Co(II) and Cu(II) complexes in DMF were found to be similar, they behave as non electrolytes in contrast to Ni(II) complexes which are 1:1 electrolytes. The electronic spectra of these metal(II) complexes were found to be different for both their solid forms and in solutions of DMF and DMSO and this has been discussed. The thiomethylated aniline ligands possess the amine and thioether groups which are present in many known biologically active compounds, hence the biological activity of the ligands and their metal complexes were tested against three strains of bacteria and one fungus. The methoxy-substituted derivatives were found to possess better inhibitory activity and this was similarly reflected in the metal(II) complexes. The activity of the complexes can be said to be in the order, Cu(II) > Co(II) > Ni(II). The Schiff-base derivatives were prepared from the ligands and para-methoxysalicylaldehyde and their Cu(II) complexes were synthesized in order to determine their biological activity. The Schiff-base ligands were found to be less active than their parent ligands. The Cu(II) complexes are not soluble in water, DMSO or DMF, as a result and could not be evaluated for their biological activity. Based on the good results from the antimicrobial evaluation, the antiplasmodial activity of some of the Co(II), Ni(II) and Cu(II) complexes of the thiomethylated ligands against Plasmodium falciparum (FCR-3) was determined. At 50 μM concentration level, the Cu(II) complexes show activity equal or better than the prophylactic chloroquine. The Cu(II) complexes with the methoxy-substituted demonstrated exceptional activity but their Co(II) and Ni(II) analogues did not show any activity. The cytotoxicity of the active Cu(II) complexes at 50 μM concentration was determined against the breast cancer cell line (MDA-MB-231). The compounds destroyed the cancer cell in the range of 28–40%, thus showing their preferred activity against the parasitic cell instead of the cancer cell. The selectivity demonstrated by these compounds have shown them to be potential antimalarial agents and this could be further investigated.
- Full Text:
- Date Issued: 2013
- Authors: Olalekan, Temitope Elizabeth
- Date: 2013
- Subjects: Aniline , Schiff bases , Ligands , Nuclear magnetic resonance spectroscopy , Chelates , X-ray crystallography , Antimalarials
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4562 , http://hdl.handle.net/10962/d1020868
- Description: A series of 31 sulfur-nitrogen donor ligands and 64 metal(II) complexes have been investigated. The thiomethylated aniline ligands 2–(methylthiomethyl)aniline 2MT and 2–(methylthio)aniline 2MA were synthesized with their substituted derivatives (-Me, -MeO, -Cl, -Br, -NO2) to serve as chelating agents. These ligands behave as bidentate ligands with SN donor group with Co(II), Ni(II) and Cu(II). The Co(II) and Ni(II) complexes have the ML2Cl2 molecular formula while the Cu(II) complexes formed with MLCl2 stoichiometry where L is the bidentate ligand. The ligands and their metal(II) complexes have been characterized by elemental analysis and with spectroscopic techniques. The trend observed in the NMR spectra and IR frequencies of the thiomethylated compounds shows there is a significant difference between the 2MT and 2MA series as a result of sulfur lone pairs extending the conjugation of the aromatic ring in the case of the latter. The effect of the position and electronic nature of ring substituent on the NMR shifts of the amine protons is discussed. The 6- and 5-membered chelate complexes formed by the 2MT and 2MA ligands respectively do not show significant diversity in their spectroscopic properties. From the elemental analysis for the Co(II) and Ni(II) complexes, their compositions reveal 1:2 M:L stoichiometry with 2 chlorine atoms from the respective metal salts. In addition, the spectroscopic data are largely indicative of tetragonally distorted structures for these solid complexes. The X-ray crystallography data reveal the Cu(II) complexes exist as square pyramidal dimers and with long Cu–Cl equitorial bonds fit into the tetragonally distorted octahedral structure. The electrolytic nature of Co(II) and Cu(II) complexes in DMF were found to be similar, they behave as non electrolytes in contrast to Ni(II) complexes which are 1:1 electrolytes. The electronic spectra of these metal(II) complexes were found to be different for both their solid forms and in solutions of DMF and DMSO and this has been discussed. The thiomethylated aniline ligands possess the amine and thioether groups which are present in many known biologically active compounds, hence the biological activity of the ligands and their metal complexes were tested against three strains of bacteria and one fungus. The methoxy-substituted derivatives were found to possess better inhibitory activity and this was similarly reflected in the metal(II) complexes. The activity of the complexes can be said to be in the order, Cu(II) > Co(II) > Ni(II). The Schiff-base derivatives were prepared from the ligands and para-methoxysalicylaldehyde and their Cu(II) complexes were synthesized in order to determine their biological activity. The Schiff-base ligands were found to be less active than their parent ligands. The Cu(II) complexes are not soluble in water, DMSO or DMF, as a result and could not be evaluated for their biological activity. Based on the good results from the antimicrobial evaluation, the antiplasmodial activity of some of the Co(II), Ni(II) and Cu(II) complexes of the thiomethylated ligands against Plasmodium falciparum (FCR-3) was determined. At 50 μM concentration level, the Cu(II) complexes show activity equal or better than the prophylactic chloroquine. The Cu(II) complexes with the methoxy-substituted demonstrated exceptional activity but their Co(II) and Ni(II) analogues did not show any activity. The cytotoxicity of the active Cu(II) complexes at 50 μM concentration was determined against the breast cancer cell line (MDA-MB-231). The compounds destroyed the cancer cell in the range of 28–40%, thus showing their preferred activity against the parasitic cell instead of the cancer cell. The selectivity demonstrated by these compounds have shown them to be potential antimalarial agents and this could be further investigated.
- Full Text:
- Date Issued: 2013
Structural analysis of synthetic ferrihydrite nanoparticles and its reduction in a hydrogen atmosphere
- Authors: Masina, Colani John
- Date: 2013
- Subjects: Ferric hydroxides , Minerals -- Analysis , Nanoparticles
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10555 , http://hdl.handle.net/10948/d1020796
- Description: Ferrihydrite (FHYD), a nanocrystalline material has long been described as a poorly crystalline disordered mineral mainly due to its small crystal size which is typically 2−6 𝑛𝑚. The three-dimensional structure of the mineral has long been described by a multi-phase structural model that consists of Fe3+ only in octahedral (Oh) coordination. In this model ferrihydrite is described as a mixture of two major phases (akaganeite/goethite-like f-phase and feroxyhite-like d-phase) and a minor ultradispersed nanohematite phase. This model has been recently challenged and a new, single-phase model was proposed, having a basic structural motif closely related to the Baker-Figgs δ-Keggin cluster and is isostructural with the mineral akdalaite, Al10O14(OH)2. In its ideal form, the proposed new structure of FHYD consist of 80 % Oh and 20 % tetrahedral (Td) Fe3+ polyhedra which can be adequately described by a single-domain model with the hexagonal spacegroup 𝑃63𝑚𝑐 and unit cell dimensions 𝑎=5.95 Å and 𝑐=9.06 Å. In this study, nanoparticles of 2-line FHYD (FHYD2), 2-line FHYD deposited onto SiO2 (FHYD2/SiO2) and 6-line FHYD (FHYD6) synthesised using rapid hydrolysis of Fe(NO3)3.9H2O solutions were characterized using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), Mössbauer spectroscopy (MS) as well as magnetization and magnetic susceptibility measurements. The coordination environment of iron atoms in the structure of FHYD was investigated using TEM and MS. The thermal transformation of FHYD nanoparticles was monitored through changes in the magnetization as a function of temperature and the reduction behaviour in hydrogen environment was studied using temperature programmed reduction (TPR), in-situ XRD and MS. Electron diffraction, TEM/ scanning TEM (STEM) imaging, and electron energy loss (EELS) measurements were carried out on three different microscopes viz. JEOL JEM-2100 LaB6 TEM, aberration corrected Schottky-FEG JEOL JEM-ARM200F HRTEM and cold-FEG Zeiss SESAM TEM. EELS studies were concentrated mainly on the iron 𝐿-edge of FHYD and iron oxides reference spectra with well known crystal structures. The iron oxide Fe 𝐿-edge is usually characterized by two intense sharp peaks termed “white lines”. The fine structures introduced by the crystal field effect on the 𝐿- edge contain information that is highly specific to the Fe3+ site symmetry.
- Full Text:
- Date Issued: 2013
- Authors: Masina, Colani John
- Date: 2013
- Subjects: Ferric hydroxides , Minerals -- Analysis , Nanoparticles
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10555 , http://hdl.handle.net/10948/d1020796
- Description: Ferrihydrite (FHYD), a nanocrystalline material has long been described as a poorly crystalline disordered mineral mainly due to its small crystal size which is typically 2−6 𝑛𝑚. The three-dimensional structure of the mineral has long been described by a multi-phase structural model that consists of Fe3+ only in octahedral (Oh) coordination. In this model ferrihydrite is described as a mixture of two major phases (akaganeite/goethite-like f-phase and feroxyhite-like d-phase) and a minor ultradispersed nanohematite phase. This model has been recently challenged and a new, single-phase model was proposed, having a basic structural motif closely related to the Baker-Figgs δ-Keggin cluster and is isostructural with the mineral akdalaite, Al10O14(OH)2. In its ideal form, the proposed new structure of FHYD consist of 80 % Oh and 20 % tetrahedral (Td) Fe3+ polyhedra which can be adequately described by a single-domain model with the hexagonal spacegroup 𝑃63𝑚𝑐 and unit cell dimensions 𝑎=5.95 Å and 𝑐=9.06 Å. In this study, nanoparticles of 2-line FHYD (FHYD2), 2-line FHYD deposited onto SiO2 (FHYD2/SiO2) and 6-line FHYD (FHYD6) synthesised using rapid hydrolysis of Fe(NO3)3.9H2O solutions were characterized using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), Mössbauer spectroscopy (MS) as well as magnetization and magnetic susceptibility measurements. The coordination environment of iron atoms in the structure of FHYD was investigated using TEM and MS. The thermal transformation of FHYD nanoparticles was monitored through changes in the magnetization as a function of temperature and the reduction behaviour in hydrogen environment was studied using temperature programmed reduction (TPR), in-situ XRD and MS. Electron diffraction, TEM/ scanning TEM (STEM) imaging, and electron energy loss (EELS) measurements were carried out on three different microscopes viz. JEOL JEM-2100 LaB6 TEM, aberration corrected Schottky-FEG JEOL JEM-ARM200F HRTEM and cold-FEG Zeiss SESAM TEM. EELS studies were concentrated mainly on the iron 𝐿-edge of FHYD and iron oxides reference spectra with well known crystal structures. The iron oxide Fe 𝐿-edge is usually characterized by two intense sharp peaks termed “white lines”. The fine structures introduced by the crystal field effect on the 𝐿- edge contain information that is highly specific to the Fe3+ site symmetry.
- Full Text:
- Date Issued: 2013
Strategies to provide holistic care and support to children who are AIDS orphans living in township communities
- Authors: Frood, Sharron Louise
- Date: 2013
- Subjects: Children of AIDS patients -- Care -- South Africa , Orphans -- Care -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10064 , http://hdl.handle.net/10948/d1020655
- Description: The human immunodeficiency virus/acquired immune-deficiency syndrome pandemic (HIV/AIDS) continues to increase in prevalence worldwide, particularly in South Africa. “AIDS, (Acquired Immune Deficiency Syndrome), has devastated the social and economic fabric of African societies, made orphans of a whole generation of children and become the epicentre of the HIV/AIDS pandemic” (Fassin, 2007: 76). Like the virus itself, the AIDS crisis mutates rapidly. Children who are AIDS orphans living in South Africa, as in other African countries, suffer from recurrent psychological trauma. It starts with the illness and death of their parents and is followed by cycles of poverty, malnutrition, stigma, exploitation, sickness and often sexual abuse. The figures concerning those affected, which are staggering, offer various predictions regarding the number of orphans left in the wake of the pandemic. Between 1990 and 2003, the number of orphaned children rose from fewer than 1 million to more than 12 million in sub-Saharan Africa (UNICEF, 2005: 68). South Africa is severely affected by the AIDS pandemic, with the largest number of HIV infections in the world, a total of 5.7 million (RSA, 2010: 10), affecting approximately 3.2 million women and 280 000 children aged from 0 to14 years. There is a significant variation in HIV prevalence per province, with the Eastern Cape (EC) reportedly having an average prevalence rate of 28 percent. Hence South Africa is likely to be the country with highest percentage of children orphaned by AIDS within its population. Orphanhood is a major consequence of the AIDS pandemic in South Africa with an estimated 2.2 million AIDS-orphaned children, 11,188 per 100,000 by 2015. Most children who are AIDS orphans living in township communities live predominantly uncared for and unsupported. Therefore the purpose of this research study was to develop strategies to provide care and support to children who are AIDS orphans living in township communities. To achieve the purpose of this research study, a qualitative, exploratory, descriptive and contextual design was used by the researcher to gain insight from health and social care practitioners who render care and support to children who are AIDS orphans living in these communities. The data from in-depth interviews with the health and social care practitoners was used by the researcher to develop strategies to provide care and support to children who are AIDS orphans living in township communities. The study comprised the following four phases: Phase One: During this phase, the researcher will present an overview of the current legislative framework policies at an international, national and provincial level, regarding the the rights of children living in South Africa. Phase Two: During this phase data from two research populations were collected and analysed. As the research process of this study dealt with two groups of participants, namely in group one health care practitioners and group two comprised social workers and psychologists, who work in the township communities to provide care and support to children who are AIDS orphans living in these communities. The researcher discussed each group separately in the discussion of phase two of the study. Phase Three: Comprised the themes identified in the data gathered from the transcribed in-depth interviews, the field notes as well as the reflective journals were cross-validated to ensure trustworthiness of the data which was then organised into a conceptual framework. The conceptual framework was used to clarify the relationships of the concepts and the themes identified during the research process and also used to link the gathered data to previously established models and theories (Schneider, 2004: 133). Phase Four: The last phase of the research design, focused on the development of the “Steps of progression strategies” to provide holistic care and support to children who are AIDS orphans living in township communities. This was done making use of the themes identified during data analysis and the literature sources used throughout this research process. The evaluation criteria of Chinn and Kramer (2008: 237-248) were used to evaluate the strategies. It is therefore concluded that the researcher succeeded in achieving the purpose of this study because strategies which were understandable, clear, simple, applicable and significant to nursing practice have been developed for use by the Department of Health and Department of Social Development as well as primary health and social care practitioners to provide holistic care and support to children who are AIDS orphans living in township communities in South Africa.
- Full Text:
- Date Issued: 2013
- Authors: Frood, Sharron Louise
- Date: 2013
- Subjects: Children of AIDS patients -- Care -- South Africa , Orphans -- Care -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10064 , http://hdl.handle.net/10948/d1020655
- Description: The human immunodeficiency virus/acquired immune-deficiency syndrome pandemic (HIV/AIDS) continues to increase in prevalence worldwide, particularly in South Africa. “AIDS, (Acquired Immune Deficiency Syndrome), has devastated the social and economic fabric of African societies, made orphans of a whole generation of children and become the epicentre of the HIV/AIDS pandemic” (Fassin, 2007: 76). Like the virus itself, the AIDS crisis mutates rapidly. Children who are AIDS orphans living in South Africa, as in other African countries, suffer from recurrent psychological trauma. It starts with the illness and death of their parents and is followed by cycles of poverty, malnutrition, stigma, exploitation, sickness and often sexual abuse. The figures concerning those affected, which are staggering, offer various predictions regarding the number of orphans left in the wake of the pandemic. Between 1990 and 2003, the number of orphaned children rose from fewer than 1 million to more than 12 million in sub-Saharan Africa (UNICEF, 2005: 68). South Africa is severely affected by the AIDS pandemic, with the largest number of HIV infections in the world, a total of 5.7 million (RSA, 2010: 10), affecting approximately 3.2 million women and 280 000 children aged from 0 to14 years. There is a significant variation in HIV prevalence per province, with the Eastern Cape (EC) reportedly having an average prevalence rate of 28 percent. Hence South Africa is likely to be the country with highest percentage of children orphaned by AIDS within its population. Orphanhood is a major consequence of the AIDS pandemic in South Africa with an estimated 2.2 million AIDS-orphaned children, 11,188 per 100,000 by 2015. Most children who are AIDS orphans living in township communities live predominantly uncared for and unsupported. Therefore the purpose of this research study was to develop strategies to provide care and support to children who are AIDS orphans living in township communities. To achieve the purpose of this research study, a qualitative, exploratory, descriptive and contextual design was used by the researcher to gain insight from health and social care practitioners who render care and support to children who are AIDS orphans living in these communities. The data from in-depth interviews with the health and social care practitoners was used by the researcher to develop strategies to provide care and support to children who are AIDS orphans living in township communities. The study comprised the following four phases: Phase One: During this phase, the researcher will present an overview of the current legislative framework policies at an international, national and provincial level, regarding the the rights of children living in South Africa. Phase Two: During this phase data from two research populations were collected and analysed. As the research process of this study dealt with two groups of participants, namely in group one health care practitioners and group two comprised social workers and psychologists, who work in the township communities to provide care and support to children who are AIDS orphans living in these communities. The researcher discussed each group separately in the discussion of phase two of the study. Phase Three: Comprised the themes identified in the data gathered from the transcribed in-depth interviews, the field notes as well as the reflective journals were cross-validated to ensure trustworthiness of the data which was then organised into a conceptual framework. The conceptual framework was used to clarify the relationships of the concepts and the themes identified during the research process and also used to link the gathered data to previously established models and theories (Schneider, 2004: 133). Phase Four: The last phase of the research design, focused on the development of the “Steps of progression strategies” to provide holistic care and support to children who are AIDS orphans living in township communities. This was done making use of the themes identified during data analysis and the literature sources used throughout this research process. The evaluation criteria of Chinn and Kramer (2008: 237-248) were used to evaluate the strategies. It is therefore concluded that the researcher succeeded in achieving the purpose of this study because strategies which were understandable, clear, simple, applicable and significant to nursing practice have been developed for use by the Department of Health and Department of Social Development as well as primary health and social care practitioners to provide holistic care and support to children who are AIDS orphans living in township communities in South Africa.
- Full Text:
- Date Issued: 2013
Standards to facilitate optimal experiences of short-term study abroad nursing students at a higher education institution
- Authors: Du Rand, Sussara Maria
- Date: 2013
- Subjects: Nursing -- Study and teaching -- United States , Transcultural nursing , Nursing -- Cross-cultural studies , Foreign study , Nursing students
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10066 , http://hdl.handle.net/10948/d1020659
- Description: Advances in technology have made globalization and internationalization a reality in the world. National borders are becoming more permeable and migration of goods, services, and health care workers takes place more readily. Higher Education Institutions (HEIs) have become competitors and vendors in the global knowledge economy and are expected to develop job seekers that are responsible and engaged global citizens and employees. Offering study abroad programmes is one of the ways that HEIs achieve this goal. It is estimated that in 2010, 4.7 million people studied abroad (OECD, 2012:360), and it is anticipated that this number will grow to 15 million by the year 2025 (Altbach & Knight, 2006:9). South Africa is emerging as a regional hub for study and research in sub-Saharan Africa (UNESCO: 2012b). Many organizations that train nurses are internationalizing their curriculum which effectively means that Schools of Nursing are seeking placement for students to study, gain insight into other cultures and practices, and to gain clinical experience in other countries. Students, the customers of the Higher Education Institutions, often pay large sums of money to undertake these study abroad programmes and therefore expect good quality learning experiences in return. The aim of this qualitative, contextual, exploratory, and descriptive study was to explore and describe the expectations and experiences of international nursing students and faculty members at a Higher Educational Institution in South Africa in order to develop standards that will enable HEIs to optimize the experiences of short-term study abroad nursing students. An in-depth contextual investigation was conducted on globalization and internationalization, as well as the higher education and health systems of three countries to understand the context of the study abroad programmes. Qualitative data was gathered from students and faculty members using focus groups and individual interviews to establish their expectations and experiences of the programme. Thematic synthesis was carried out on the contextual data and the qualitative data. Thereafter, thematic synthesis analysis was conducted using both sets of results to develop standards that can be used to optimize the experience of short-term study abroad nursing students at a HEI. A total of 35 standards were developed around the following main themes: the objectives of study abroad programmes should be stated clearly before arrival and include the expectations of the global, national, and local communities, the higher education institution and the staff and students; study abroad programmes should be managed in an ethical manner and in an enabling environment, as part of their strategic goals and plans of a HEI; students should be exposed to a variety of experiences and differences between the sending and hosting countries during their study abroad programmes; Standards to Facilitate Optimal Experiences of Short-term Study Abroad Nursing Students at a HEI; study abroad programmes should be evaluated at different intervals and levels to ensure quality of the programmes and to ensure that the objectives/outcomes are met. A limitation of the study was the sampling of the clinical mentors which did not include representatives from the overseas universities. It is recommended that the standards that were developed in this study be introduced and tested in HEIs and that more research be conducted on different levels and groups with regard to study abroad programmes in future.
- Full Text:
- Date Issued: 2013
- Authors: Du Rand, Sussara Maria
- Date: 2013
- Subjects: Nursing -- Study and teaching -- United States , Transcultural nursing , Nursing -- Cross-cultural studies , Foreign study , Nursing students
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10066 , http://hdl.handle.net/10948/d1020659
- Description: Advances in technology have made globalization and internationalization a reality in the world. National borders are becoming more permeable and migration of goods, services, and health care workers takes place more readily. Higher Education Institutions (HEIs) have become competitors and vendors in the global knowledge economy and are expected to develop job seekers that are responsible and engaged global citizens and employees. Offering study abroad programmes is one of the ways that HEIs achieve this goal. It is estimated that in 2010, 4.7 million people studied abroad (OECD, 2012:360), and it is anticipated that this number will grow to 15 million by the year 2025 (Altbach & Knight, 2006:9). South Africa is emerging as a regional hub for study and research in sub-Saharan Africa (UNESCO: 2012b). Many organizations that train nurses are internationalizing their curriculum which effectively means that Schools of Nursing are seeking placement for students to study, gain insight into other cultures and practices, and to gain clinical experience in other countries. Students, the customers of the Higher Education Institutions, often pay large sums of money to undertake these study abroad programmes and therefore expect good quality learning experiences in return. The aim of this qualitative, contextual, exploratory, and descriptive study was to explore and describe the expectations and experiences of international nursing students and faculty members at a Higher Educational Institution in South Africa in order to develop standards that will enable HEIs to optimize the experiences of short-term study abroad nursing students. An in-depth contextual investigation was conducted on globalization and internationalization, as well as the higher education and health systems of three countries to understand the context of the study abroad programmes. Qualitative data was gathered from students and faculty members using focus groups and individual interviews to establish their expectations and experiences of the programme. Thematic synthesis was carried out on the contextual data and the qualitative data. Thereafter, thematic synthesis analysis was conducted using both sets of results to develop standards that can be used to optimize the experience of short-term study abroad nursing students at a HEI. A total of 35 standards were developed around the following main themes: the objectives of study abroad programmes should be stated clearly before arrival and include the expectations of the global, national, and local communities, the higher education institution and the staff and students; study abroad programmes should be managed in an ethical manner and in an enabling environment, as part of their strategic goals and plans of a HEI; students should be exposed to a variety of experiences and differences between the sending and hosting countries during their study abroad programmes; Standards to Facilitate Optimal Experiences of Short-term Study Abroad Nursing Students at a HEI; study abroad programmes should be evaluated at different intervals and levels to ensure quality of the programmes and to ensure that the objectives/outcomes are met. A limitation of the study was the sampling of the clinical mentors which did not include representatives from the overseas universities. It is recommended that the standards that were developed in this study be introduced and tested in HEIs and that more research be conducted on different levels and groups with regard to study abroad programmes in future.
- Full Text:
- Date Issued: 2013