Malarial drug targets cysteine proteases as hemoglobinases
- Authors: Mokoena, Fortunate
- Date: 2012
- Subjects: Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4005 , http://hdl.handle.net/10962/d1004065 , Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Description: Malaria has consistently been rated as the worst parasitic disease in the world. This disease affects an estimated 5 billion households annually. Malaria has a high mortality rate leading to distorted socio-economic development of the world at large. The major challenge pertaining to malaria is its continuous and rapid spread together with the emergence of drug resistance in Plasmodium species (vector agent of the disease). For this reason, researchers throughout the world are following new leads for possible drug targets and therefore, investigating ways of curbing the spread of the disease. Cysteine proteases have emerged as potential antimalarial chemotherapeutic targets. These particular proteases are found in all living organisms, Plasmodium cysteine proteases are known to degrade host hemoglobin during the life cycle of the parasite within the human host. The main objective of this study was to use various in silico methods to analyze the hemoglobinase function of cysteine proteases in P. falciparum and P. vivax. Falcipain-2 (FP2) of P. falciparum is the best characterized of these enzymes, it is a validated drug target. Both the three-dimensional structures of FP2 and its close homologue falcipain-3 (FP3) have been solved by the experimental technique X-ray crystallography. However, the homologue falcipain-2 (FP2’)’ and orthologues from P.vivax vivapain-2 (VP2) and vivapain-3 (VP3) have yet to be elucidated by experimental techniques. In an effort to achieve the principal goal of the study, homology models of the protein structures not already elucidated by experimental methods (FP2’, VP2 and VP3) were calculated using the well known spatial restraint program MODELLER. The derived models, FP2 and FP3 were docked to hemoglobin (their natural substrate). The protein-protein docking was done using the unbound docking program ZDOCK. The substrate-enzyme interactions were analyzed and amino acids involved in binding were observed. It is anticipated that the results obtained from the study will help focus inhibitor design for potential drugs against malaria. The residues found in both the P. falciparum and P. vivax cysteine proteases involved in hemoglobin binding have been identified and some of these are proposed to be the main focus for the design of a peptidomimetric inhibitor.
- Full Text:
- Authors: Mokoena, Fortunate
- Date: 2012
- Subjects: Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4005 , http://hdl.handle.net/10962/d1004065 , Malaria -- Chemotherapy , Antimalarials , Hemoglobin , Proteolytic enzymes , Cysteine proteinases , Plasmodium falciparum , Plasmodium vivax , Papain
- Description: Malaria has consistently been rated as the worst parasitic disease in the world. This disease affects an estimated 5 billion households annually. Malaria has a high mortality rate leading to distorted socio-economic development of the world at large. The major challenge pertaining to malaria is its continuous and rapid spread together with the emergence of drug resistance in Plasmodium species (vector agent of the disease). For this reason, researchers throughout the world are following new leads for possible drug targets and therefore, investigating ways of curbing the spread of the disease. Cysteine proteases have emerged as potential antimalarial chemotherapeutic targets. These particular proteases are found in all living organisms, Plasmodium cysteine proteases are known to degrade host hemoglobin during the life cycle of the parasite within the human host. The main objective of this study was to use various in silico methods to analyze the hemoglobinase function of cysteine proteases in P. falciparum and P. vivax. Falcipain-2 (FP2) of P. falciparum is the best characterized of these enzymes, it is a validated drug target. Both the three-dimensional structures of FP2 and its close homologue falcipain-3 (FP3) have been solved by the experimental technique X-ray crystallography. However, the homologue falcipain-2 (FP2’)’ and orthologues from P.vivax vivapain-2 (VP2) and vivapain-3 (VP3) have yet to be elucidated by experimental techniques. In an effort to achieve the principal goal of the study, homology models of the protein structures not already elucidated by experimental methods (FP2’, VP2 and VP3) were calculated using the well known spatial restraint program MODELLER. The derived models, FP2 and FP3 were docked to hemoglobin (their natural substrate). The protein-protein docking was done using the unbound docking program ZDOCK. The substrate-enzyme interactions were analyzed and amino acids involved in binding were observed. It is anticipated that the results obtained from the study will help focus inhibitor design for potential drugs against malaria. The residues found in both the P. falciparum and P. vivax cysteine proteases involved in hemoglobin binding have been identified and some of these are proposed to be the main focus for the design of a peptidomimetric inhibitor.
- Full Text:
Managing an inclusive school: a case study of a pilot school in Swaziland
- Authors: Zimba, Zondani
- Date: 2012
- Subjects: Inclusive education -- Swaziland -- Mbabane Special education -- Swaziland -- Mbabane Learning disabled children -- Education -- Swaziland -- Mbabane Students with disabilities -- Swaziland -- Mbabane School management and organization -- Swaziland -- Mbabane
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1669 , http://hdl.handle.net/10962/d1003552
- Description: Inclusive Education (IE) reflects the values, ethos, and culture of an education system committed to excellence by promoting education opportunities for all learners. IE is about building a more just society and ensuring the right to education for all learners regardless of their individual characteristics or difficulties (UNESCO: 2007). The kingdom of Swaziland has committed itself to high quality basic education which provides equal opportunities for all children and youth. This is evident in the Swaziland National Constitution (2006). To promote Education for All (EFA) as stated in the constitution, an IE Policy has been developed and a draft policy is in place. The programme has been operational since 2006. There are nine pilot schools and four teachers from each school who have been trained on how to handle pupils with disabilities. The programme will be rolled out to 608 primary schools by 2015. In this research, the goal was to investigate how a School Management Board responds to the challenges of managing an Inclusive School. This research is a qualitative interpretive case study based in one of the pilot schools in Mbabane in Swaziland. The study used document analysis, semi‐structured interviews and focus groups to collect data. The study revealed that the school has done much in accommodating IE as there are changes in management structures and approaches, organizational culture and operating procedures. On the other hand, there are still significant challenges such as a lack of knowledge of inclusion and negativity on the part of learners and parents. Other challenges include inadequate training for educators and lack of suitable infrastructure. The study concludes by recommending improved staff development programmes, infrastructure upgrades, acquiring appropriate teaching and learning resources and employing multidisciplinary personnel.
- Full Text:
- Authors: Zimba, Zondani
- Date: 2012
- Subjects: Inclusive education -- Swaziland -- Mbabane Special education -- Swaziland -- Mbabane Learning disabled children -- Education -- Swaziland -- Mbabane Students with disabilities -- Swaziland -- Mbabane School management and organization -- Swaziland -- Mbabane
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1669 , http://hdl.handle.net/10962/d1003552
- Description: Inclusive Education (IE) reflects the values, ethos, and culture of an education system committed to excellence by promoting education opportunities for all learners. IE is about building a more just society and ensuring the right to education for all learners regardless of their individual characteristics or difficulties (UNESCO: 2007). The kingdom of Swaziland has committed itself to high quality basic education which provides equal opportunities for all children and youth. This is evident in the Swaziland National Constitution (2006). To promote Education for All (EFA) as stated in the constitution, an IE Policy has been developed and a draft policy is in place. The programme has been operational since 2006. There are nine pilot schools and four teachers from each school who have been trained on how to handle pupils with disabilities. The programme will be rolled out to 608 primary schools by 2015. In this research, the goal was to investigate how a School Management Board responds to the challenges of managing an Inclusive School. This research is a qualitative interpretive case study based in one of the pilot schools in Mbabane in Swaziland. The study used document analysis, semi‐structured interviews and focus groups to collect data. The study revealed that the school has done much in accommodating IE as there are changes in management structures and approaches, organizational culture and operating procedures. On the other hand, there are still significant challenges such as a lack of knowledge of inclusion and negativity on the part of learners and parents. Other challenges include inadequate training for educators and lack of suitable infrastructure. The study concludes by recommending improved staff development programmes, infrastructure upgrades, acquiring appropriate teaching and learning resources and employing multidisciplinary personnel.
- Full Text:
Microalgae biomass as fermentation feedstock
- Authors: Tijjani-Oshungboye, Kubura
- Date: 2012
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5956 , http://hdl.handle.net/10962/d1006168
- Description: The search for alternative energy is as a result of pollution generated by the utilization of fossil fuel. Bearing in mind the increase in demand which exceeds supply, alternative energy must reduce the carbon foot print in order to relieve use of fossil fuels. Biogas generation from wastes is an old technology that has been in existence for decades. This same concept was behind the development of the integrated algae ponding system (IAPS), where the use of microalgae biomass is adopted for waste water treatment and, anaerobic digestion which is a component of the IAPS, simultaneously generates biogas. The biogas from the IAPS was quantified in order to evaluate efficiency of the system and the anaerobic fermentation pit was also simulated in the laboratory to optimize biogas production using microalgae as co-fermentation feedstock. Microalgae biomass was evaluated as potential feedstock for ethanol fermentation and the use of biogas was investigated as an alternative transportation fuel. In an IAPS substantial biomass is produced on an annual basis. For effective treatment of waste water and efficient nutrient removal continuous harvest of the biomass is required. In the present study, water treatment efficiency of the EBRU IAPS was determined by carrying out a series of tests to investigate the decline in nutrient content from port of influent entry to effluent discharge. There was more than a 60% reduction in nutrient content with a concomitant increase in biomass and growth rate of 0.25 g/L . Biogas generated from the IAPS was quantified using a flow meter and the composition determined by gas chromatography. Methane which is the principal constituent of biogas was 75% (±SD, n=IO) and 2.34 m³.d⁻¹ was measured as biogas yield from the EBRU IAPS. The study also investigated the use of the excess microalgae biomass as a fermentation feedstock for ethanol production and as a co-substrate in order to increase biogas yield from the system. Positive results were achieved for ethanol production from microalgae although yield was generally low. About 385 mg.⁻¹ of ethanol was recovered when glucose was used as substrate, where as only 115 mg.⁻¹ of ethanol was recovered with microalgae as substrate. Suitability of microalgae as feedstock for ethanol generation and biogas generation was determined by characterisation which involved estimation of the carbohydrate, protein and lipid content, and analysis of the C, H, 0, Nand S content. Laboratory fed batch reactors simulated the anaerobic digestion process in order to study the effect of microalgae biomass as co-substrate for biogas generation. The fermenters were inoculated with an active consortium obtained from the Makana municipal waste water works and microbial studies were carried to confirm the presence of the anaerobic consortium. Different pre-treatments (concentrated, rupturing and freeze-drying) were used to disrupt the microalgae prior to introduction into fermenters in a ratio of 3: I. COD, TC, TOC, SO₄⁻² and TN analyses were carried out to monitor nutrient depletion in the system, and biogas generated by the system was quantified by volumetric analysis and the gas composition determined. Statistical analysis (ANOVA) was used to test for significant difference pre and post addition of microalgae. In the most effective fermenter, biogas production was at an average of 394 ml.d·' and CH₄ ratio in the biogas increased by over a 100%. Theoretical methane potential of the IAPS and the Makana municipal waste water works treating 5 ML.d⁻¹ of domestic waste was determined using the empirical formula of waste water and shown to yield 1,037,342.40 m³/yr. The projected biogas yield from this system was used to evaluate its potential use as transportation fuel. In total, 198,673 .55 m³ of biogas was estimated to be required to fuel the Rhodes University's fleet of vehicles, with a residual biogas stream of 838,668.85 m³. It was also demonstrated in the present study that renewable energy sourced from biomass has the potential of supplanting the use of fossil fuel resulting in less pollution leading to a cleaner and healthier environment.
- Full Text:
- Authors: Tijjani-Oshungboye, Kubura
- Date: 2012
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5956 , http://hdl.handle.net/10962/d1006168
- Description: The search for alternative energy is as a result of pollution generated by the utilization of fossil fuel. Bearing in mind the increase in demand which exceeds supply, alternative energy must reduce the carbon foot print in order to relieve use of fossil fuels. Biogas generation from wastes is an old technology that has been in existence for decades. This same concept was behind the development of the integrated algae ponding system (IAPS), where the use of microalgae biomass is adopted for waste water treatment and, anaerobic digestion which is a component of the IAPS, simultaneously generates biogas. The biogas from the IAPS was quantified in order to evaluate efficiency of the system and the anaerobic fermentation pit was also simulated in the laboratory to optimize biogas production using microalgae as co-fermentation feedstock. Microalgae biomass was evaluated as potential feedstock for ethanol fermentation and the use of biogas was investigated as an alternative transportation fuel. In an IAPS substantial biomass is produced on an annual basis. For effective treatment of waste water and efficient nutrient removal continuous harvest of the biomass is required. In the present study, water treatment efficiency of the EBRU IAPS was determined by carrying out a series of tests to investigate the decline in nutrient content from port of influent entry to effluent discharge. There was more than a 60% reduction in nutrient content with a concomitant increase in biomass and growth rate of 0.25 g/L . Biogas generated from the IAPS was quantified using a flow meter and the composition determined by gas chromatography. Methane which is the principal constituent of biogas was 75% (±SD, n=IO) and 2.34 m³.d⁻¹ was measured as biogas yield from the EBRU IAPS. The study also investigated the use of the excess microalgae biomass as a fermentation feedstock for ethanol production and as a co-substrate in order to increase biogas yield from the system. Positive results were achieved for ethanol production from microalgae although yield was generally low. About 385 mg.⁻¹ of ethanol was recovered when glucose was used as substrate, where as only 115 mg.⁻¹ of ethanol was recovered with microalgae as substrate. Suitability of microalgae as feedstock for ethanol generation and biogas generation was determined by characterisation which involved estimation of the carbohydrate, protein and lipid content, and analysis of the C, H, 0, Nand S content. Laboratory fed batch reactors simulated the anaerobic digestion process in order to study the effect of microalgae biomass as co-substrate for biogas generation. The fermenters were inoculated with an active consortium obtained from the Makana municipal waste water works and microbial studies were carried to confirm the presence of the anaerobic consortium. Different pre-treatments (concentrated, rupturing and freeze-drying) were used to disrupt the microalgae prior to introduction into fermenters in a ratio of 3: I. COD, TC, TOC, SO₄⁻² and TN analyses were carried out to monitor nutrient depletion in the system, and biogas generated by the system was quantified by volumetric analysis and the gas composition determined. Statistical analysis (ANOVA) was used to test for significant difference pre and post addition of microalgae. In the most effective fermenter, biogas production was at an average of 394 ml.d·' and CH₄ ratio in the biogas increased by over a 100%. Theoretical methane potential of the IAPS and the Makana municipal waste water works treating 5 ML.d⁻¹ of domestic waste was determined using the empirical formula of waste water and shown to yield 1,037,342.40 m³/yr. The projected biogas yield from this system was used to evaluate its potential use as transportation fuel. In total, 198,673 .55 m³ of biogas was estimated to be required to fuel the Rhodes University's fleet of vehicles, with a residual biogas stream of 838,668.85 m³. It was also demonstrated in the present study that renewable energy sourced from biomass has the potential of supplanting the use of fossil fuel resulting in less pollution leading to a cleaner and healthier environment.
- Full Text:
Molecular chaperone expression and function in breast cancer and breast cancer stem cells
- Authors: Sterrenberg, Jason Neville
- Date: 2012
- Subjects: Breast -- Cancer , Stem cells , Cancer cells
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4141 , http://hdl.handle.net/10962/d1016238
- Description: The Cancer Stem Cell (CSC) theory suggests that cancers arise from and are maintained by a subpopulation of cancer cells with stem cell properties. Molecular chaperones are key components of cellular regulation. The overexpression of chaperones has become synonymous with cancer cells with chaperones being recognized as bona fide anti-cancer drug targets. Although chaperone activity has been characterized in cancer cells, very little is known about the cellular functions of chaperones in cancer stem cells. We set out to compare the expression of selected molecular chaperones in non-stem cancer cell and cancer stem cell enriched populations isolated from breast cancer lines, in order to identify chaperones differentially expressed between the two populations for further biological characterization. In order to isolate breast cancer stem cells from the MCF-7 and MDA-MB-231 breast cancer cell lines, three cancer stem cell isolation and identification techniques were utilized based on (1) cell surface marker expression (CD44+/CD24- and CD44+/CD24-/EpCAM+ phenotypes), (2) aldehyde dehydrogenase enzyme activity (ALDHHi) and (3) ability to grow in anchorage-independent conditions. The MDA-MB-231 and MCF-7 breast cancer cell lines displayed CD44+/CD24- cell populations with the MCF-7 cell line additionally displaying a large CD44+/CD24-/EpCAM+ population. Although both cell lines showed similar ALDHHi populations, they differed substantially with respect to anchorage-independent growth. MCF-7 cells were able to form anchorage-independent colonies while the MDA-MB-231 cell line was not. Anchorage-independent MCF-7 cells showed enrichment in CD44+/CD24- and CD44+/CD24-/EpCAM+ cells compared to adherent MCF-7 cells, and were selected for gene expression studies. Gene expression studies identified 22 genes as being down-regulated at the mRNA level in the anchorage-independent MCF-7 cells, while only 2 genes (BAG1 and DNAJC12) were up-regulated. The down-regulation of selected chaperones in anchorage independent MCF-7 cells was confirmed at the protein level for selected chaperones, including DNAJB6, a type II DNAJ protein shown to be involved in the regulation of Wnt signaling. In order to characterize the effect of DNAJB6 expression on BCSCs we developed a pCMV mammalian expression plasmid for both DNAJB6 isoforms (DNAJB6L and DNAJB6S). We successfully constructed mutants of the conserved histidine-proline-aspartic acid (HPD) motif of the J domain of DNAJB6S and DNAJB6L. These constructs will allow the analysis of the role of DNAJB6 in cancer stem cell function. To the best of our knowledge, this is the first report to focus on the comparative expression of molecular chaperones in normal and cancer stem cell enriched breast cancer populations.
- Full Text:
- Authors: Sterrenberg, Jason Neville
- Date: 2012
- Subjects: Breast -- Cancer , Stem cells , Cancer cells
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4141 , http://hdl.handle.net/10962/d1016238
- Description: The Cancer Stem Cell (CSC) theory suggests that cancers arise from and are maintained by a subpopulation of cancer cells with stem cell properties. Molecular chaperones are key components of cellular regulation. The overexpression of chaperones has become synonymous with cancer cells with chaperones being recognized as bona fide anti-cancer drug targets. Although chaperone activity has been characterized in cancer cells, very little is known about the cellular functions of chaperones in cancer stem cells. We set out to compare the expression of selected molecular chaperones in non-stem cancer cell and cancer stem cell enriched populations isolated from breast cancer lines, in order to identify chaperones differentially expressed between the two populations for further biological characterization. In order to isolate breast cancer stem cells from the MCF-7 and MDA-MB-231 breast cancer cell lines, three cancer stem cell isolation and identification techniques were utilized based on (1) cell surface marker expression (CD44+/CD24- and CD44+/CD24-/EpCAM+ phenotypes), (2) aldehyde dehydrogenase enzyme activity (ALDHHi) and (3) ability to grow in anchorage-independent conditions. The MDA-MB-231 and MCF-7 breast cancer cell lines displayed CD44+/CD24- cell populations with the MCF-7 cell line additionally displaying a large CD44+/CD24-/EpCAM+ population. Although both cell lines showed similar ALDHHi populations, they differed substantially with respect to anchorage-independent growth. MCF-7 cells were able to form anchorage-independent colonies while the MDA-MB-231 cell line was not. Anchorage-independent MCF-7 cells showed enrichment in CD44+/CD24- and CD44+/CD24-/EpCAM+ cells compared to adherent MCF-7 cells, and were selected for gene expression studies. Gene expression studies identified 22 genes as being down-regulated at the mRNA level in the anchorage-independent MCF-7 cells, while only 2 genes (BAG1 and DNAJC12) were up-regulated. The down-regulation of selected chaperones in anchorage independent MCF-7 cells was confirmed at the protein level for selected chaperones, including DNAJB6, a type II DNAJ protein shown to be involved in the regulation of Wnt signaling. In order to characterize the effect of DNAJB6 expression on BCSCs we developed a pCMV mammalian expression plasmid for both DNAJB6 isoforms (DNAJB6L and DNAJB6S). We successfully constructed mutants of the conserved histidine-proline-aspartic acid (HPD) motif of the J domain of DNAJB6S and DNAJB6L. These constructs will allow the analysis of the role of DNAJB6 in cancer stem cell function. To the best of our knowledge, this is the first report to focus on the comparative expression of molecular chaperones in normal and cancer stem cell enriched breast cancer populations.
- Full Text:
Movements of sub-adult sicklefin lemon sharks Negaprion acutidens in a remote Indian Ocean atoll
- Authors: Filmalter, John David
- Date: 2012
- Subjects: Silky shark , Silky shark -- Habitat , Sharks -- Amirante Islands (Seychelles)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5383 , http://hdl.handle.net/10962/d1018229
- Description: The sicklefin lemon shark Negaprion acutidens is a large-bodied (> 3m) coastal shark species, widely distributed in tropical and sub-tropical Indo-Pacific waters. Despite its large size and wide distribution, very little is known about its movement behaviour throughout ontogeny. The primary aim of this thesis was to gain an understanding of the movements of sub-adult N. acutidens, in and around the St. Joseph Atoll, Republic of Seychelles, to facilitate the effective conservation of this vulnerable species. A total of 22 sharks (139 – 202 cm TL) were equipped with coded acoustic transmitters and passively monitored using moored acoustic receivers for a period of 20 month from March 2009 to October 2010. The use of passive acoustic telemetry arrays to study behavioural ecology has increased in popularity in recent years and been successfully applied to study a host of teleost and elasmobranch species in a diversity of habitats, ranging from sheltered estuaries to the offshore pelagic environment. However, the practicalities of designing an effective network of receivers to optimally monitor animal movements can be challenging. In this study the receiver array was optimised through a series of incremental steps to achieve an efficient design that allowed for the specific objectives to be addressed. The specific objectives of this study were to i) gain an understanding of the long term space use patterns and site fidelity of sub-adult N. acutidens within degree of use of the St. Joseph Atoll lagoon and surrounding habitats, and ii) investigate their short term behavioural patterns in response to natural rhythmic cycles. The important role the atoll plays in the sub-adult stage of this species was demonstrated by the very low numbers of detections outside the atoll compared to the very large numbers of detections inside the atoll. Over the course of a year the tagged sharks showed a high degree of site fidelity to the atoll, with 79 – 100% of the individuals detected during each month and 50% being detected on a near daily basis. This result provides testimony of the nursery role of the atoll and importance of these habitats in the early life history for this species. Individual area use was generally found to be restricted to the eastern part of the atoll incorporating a portion of the central deep lagoon and a nearby adjacent area of the sand flats. The movements of sub-adult N. acutidens on and off of the shallow flats surrounding the central lagoon (likely for foraging) were found to be strongly influenced by the tidal height and the diel cycle. Tagged sharks were found to utilise the flats more regularly when the tidal height was greater than 90 cm and particularly more so during the night and early morning than during daylight times. The combined results of this study expose the vulnerability of this species to rapid local depletion. Similarly, the effectiveness of spatial management measures, such as no-take marine protected areas is highlighted as an efficient tool for the future conservation of this species. In the St. Joseph Atoll in particular, the use of a multi-levelled protection approach, where the eastern portion on the atoll is completely restricted while the remaining area is utilized for non-consumptive tourism activities, could be highly effective. Future research should investigate changes in area use throughout the ontogeny of this species as well improve the understanding of the breeding site fidelity and population size of reproductive females using the St. Joseph Atoll.
- Full Text:
- Authors: Filmalter, John David
- Date: 2012
- Subjects: Silky shark , Silky shark -- Habitat , Sharks -- Amirante Islands (Seychelles)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5383 , http://hdl.handle.net/10962/d1018229
- Description: The sicklefin lemon shark Negaprion acutidens is a large-bodied (> 3m) coastal shark species, widely distributed in tropical and sub-tropical Indo-Pacific waters. Despite its large size and wide distribution, very little is known about its movement behaviour throughout ontogeny. The primary aim of this thesis was to gain an understanding of the movements of sub-adult N. acutidens, in and around the St. Joseph Atoll, Republic of Seychelles, to facilitate the effective conservation of this vulnerable species. A total of 22 sharks (139 – 202 cm TL) were equipped with coded acoustic transmitters and passively monitored using moored acoustic receivers for a period of 20 month from March 2009 to October 2010. The use of passive acoustic telemetry arrays to study behavioural ecology has increased in popularity in recent years and been successfully applied to study a host of teleost and elasmobranch species in a diversity of habitats, ranging from sheltered estuaries to the offshore pelagic environment. However, the practicalities of designing an effective network of receivers to optimally monitor animal movements can be challenging. In this study the receiver array was optimised through a series of incremental steps to achieve an efficient design that allowed for the specific objectives to be addressed. The specific objectives of this study were to i) gain an understanding of the long term space use patterns and site fidelity of sub-adult N. acutidens within degree of use of the St. Joseph Atoll lagoon and surrounding habitats, and ii) investigate their short term behavioural patterns in response to natural rhythmic cycles. The important role the atoll plays in the sub-adult stage of this species was demonstrated by the very low numbers of detections outside the atoll compared to the very large numbers of detections inside the atoll. Over the course of a year the tagged sharks showed a high degree of site fidelity to the atoll, with 79 – 100% of the individuals detected during each month and 50% being detected on a near daily basis. This result provides testimony of the nursery role of the atoll and importance of these habitats in the early life history for this species. Individual area use was generally found to be restricted to the eastern part of the atoll incorporating a portion of the central deep lagoon and a nearby adjacent area of the sand flats. The movements of sub-adult N. acutidens on and off of the shallow flats surrounding the central lagoon (likely for foraging) were found to be strongly influenced by the tidal height and the diel cycle. Tagged sharks were found to utilise the flats more regularly when the tidal height was greater than 90 cm and particularly more so during the night and early morning than during daylight times. The combined results of this study expose the vulnerability of this species to rapid local depletion. Similarly, the effectiveness of spatial management measures, such as no-take marine protected areas is highlighted as an efficient tool for the future conservation of this species. In the St. Joseph Atoll in particular, the use of a multi-levelled protection approach, where the eastern portion on the atoll is completely restricted while the remaining area is utilized for non-consumptive tourism activities, could be highly effective. Future research should investigate changes in area use throughout the ontogeny of this species as well improve the understanding of the breeding site fidelity and population size of reproductive females using the St. Joseph Atoll.
- Full Text:
Moving through the city : Cape Town's legacy of slavery and the performance of creolised carnival
- Authors: Nsele, Zamansele
- Date: 2012
- Subjects: Carnival -- South Africa -- Cape Town , Cape of Good Hope (South Africa) -- Economic conditions , Cape of Good Hope (South Africa) -- Social conditions , Cape Town -- Economic conditions , Cape Town -- Social conditions , Slavery -- South Africa -- Cape Town , Stereotypes (Social psychology -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2489 , http://hdl.handle.net/10962/d1012977
- Description: After South Africa entered into democracy in 1994, a mediation period of change was set in motion. It was an invitation for South Africans to imagine and envision themselves anew (Gqola 2010). Slave memory; a neglected past, that was previously silenced came to the fore and is currently in the process of being renegotiated in post-apartheid South Africa. In the light of this, I believe that the study of the Cape Minstrel Carnival which has its social roots in slavery lends itself for an insightful interpretation within an art historical framework. While institutionally the memory of slavery was officially marginalized: comparatively, on the streets of Cape Town, the community preserved it in elusive ways embodied in the procession of Carnival through the city. This thesis explores the imagery of creolisation, through an analysis of the Cape Minstrel Carnival. Zimitri Erasmus (Erasmus 200:14) defines creolisation as cultural production that happens under the specific conditions of slavery. Before I decode some of the motifs embedded in the imagery of creolisation, in chapter one I provide an in depth analysis; of the contextual conditions of which the practice of carnival originated. My analysis is informed extensively by post-colonial theories on race, identity, and creolisation. The route of the procession of carnival reveals an alternative and clandestine history of the city of Cape Town which I believe deserves focus. In chapter two I discuss its site specificity in relation to key urban sites, such as the District Six Museum, the Slave Lodge Museum and the Bo-Kaap Museum. This thesis explores the use of performance as a corporeal tool to demarcate the city. In the process of this analysis, a repertoire of movement becomes salient in the construction of creolised identities. In chapter three I discuss the motif of the “coon” as the most salient image of creolisation in the parade; I trace its iconographic roots to the performance of blackface minstrelsy that originated from the slave plantations of the United States of America. By unpacking the racist iconography bound up in the initial construction of the “coon”, it becomes clear that its derogative meaning was subverted when it was appropriated as a symbol of celebration into the New Year’s parades. As a result of its complicated history, some residents deride the parade as perpetuating racial stereotypes, by portraying “coloured” people as buffoons. Class snobbery has played a big part in the criticism. Therefore the procession of “the coons” or euphemistically the minstrels represents a cultural cringe for some and a festive celebration for others and both these sentiments coexist simultaneously. The Cape Town Minstrel Carnival can be interpreted on multiple shifting levels because it takes on an ambivalent and ambiguous position as far as meaning is concerned.
- Full Text:
- Authors: Nsele, Zamansele
- Date: 2012
- Subjects: Carnival -- South Africa -- Cape Town , Cape of Good Hope (South Africa) -- Economic conditions , Cape of Good Hope (South Africa) -- Social conditions , Cape Town -- Economic conditions , Cape Town -- Social conditions , Slavery -- South Africa -- Cape Town , Stereotypes (Social psychology -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2489 , http://hdl.handle.net/10962/d1012977
- Description: After South Africa entered into democracy in 1994, a mediation period of change was set in motion. It was an invitation for South Africans to imagine and envision themselves anew (Gqola 2010). Slave memory; a neglected past, that was previously silenced came to the fore and is currently in the process of being renegotiated in post-apartheid South Africa. In the light of this, I believe that the study of the Cape Minstrel Carnival which has its social roots in slavery lends itself for an insightful interpretation within an art historical framework. While institutionally the memory of slavery was officially marginalized: comparatively, on the streets of Cape Town, the community preserved it in elusive ways embodied in the procession of Carnival through the city. This thesis explores the imagery of creolisation, through an analysis of the Cape Minstrel Carnival. Zimitri Erasmus (Erasmus 200:14) defines creolisation as cultural production that happens under the specific conditions of slavery. Before I decode some of the motifs embedded in the imagery of creolisation, in chapter one I provide an in depth analysis; of the contextual conditions of which the practice of carnival originated. My analysis is informed extensively by post-colonial theories on race, identity, and creolisation. The route of the procession of carnival reveals an alternative and clandestine history of the city of Cape Town which I believe deserves focus. In chapter two I discuss its site specificity in relation to key urban sites, such as the District Six Museum, the Slave Lodge Museum and the Bo-Kaap Museum. This thesis explores the use of performance as a corporeal tool to demarcate the city. In the process of this analysis, a repertoire of movement becomes salient in the construction of creolised identities. In chapter three I discuss the motif of the “coon” as the most salient image of creolisation in the parade; I trace its iconographic roots to the performance of blackface minstrelsy that originated from the slave plantations of the United States of America. By unpacking the racist iconography bound up in the initial construction of the “coon”, it becomes clear that its derogative meaning was subverted when it was appropriated as a symbol of celebration into the New Year’s parades. As a result of its complicated history, some residents deride the parade as perpetuating racial stereotypes, by portraying “coloured” people as buffoons. Class snobbery has played a big part in the criticism. Therefore the procession of “the coons” or euphemistically the minstrels represents a cultural cringe for some and a festive celebration for others and both these sentiments coexist simultaneously. The Cape Town Minstrel Carnival can be interpreted on multiple shifting levels because it takes on an ambivalent and ambiguous position as far as meaning is concerned.
- Full Text:
Multi-instrument observations of ionospheric irregularities over South Africa
- Authors: Amabayo, Emirant Bertillas
- Date: 2012
- Subjects: Ionosphere -- Research , Sudden ionospheric disturbances , Ionospheric storms , Solar activity , Sunspots
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5476 , http://hdl.handle.net/10962/d1005261 , Ionosphere -- Research , Sudden ionospheric disturbances , Ionospheric storms , Solar activity , Sunspots
- Description: The occurrence of mid-latitude spread F (SF) over South Africa has not been extensively studied since the installation of the DPS-4 digisondes at Madimbo (30.88◦E, 22.38◦S), Grahamstown (33.32◦S, 26.50◦E) and Louisvale (28.51◦S, 21.24◦E). This study is intended to quantify the probability of the occurrence of F region disturbances associated with ionospheric spread F (SF) and L-band scintillation over South Africa. This study used available ionosonde data for 8 years (2000-2008) from the three South African stations. The SF events were identified manually on ionograms and grouped for further statistical analysis into frequency SF (FSF), range SF (RSF) and mixed SF (MSF). The results show that the diurnal pattern of SF occurrence peaks strongly between 23:00 and 00:00 UT. This pattern is true for all seasons and types of SF at Madimbo and Grahamstown during 2001 and 2005, except for RSF which had peaks during autumn and spring during 2001 at Madimbo. The probability of both MSF and FSF tends to increase with decreasing sunspot number (SSN), with a peak in 2005 (a moderate solar activity period). The seasonal peaks of MSF and FSF are more frequent during winter months at both Madimbo and Grahamstown. In this study SF was evident in ∼ 0.03% and ∼ 0.06% of the available ionograms at Madimbo and Grahamstown respectively during the eight year period. The presence of ionospheric irregularities associated with SF and scintillation was investigated using data from selected Global Positioning System (GPS) receiver stations distributed across South Africa. The results, based on GPS total electron content (TEC) and ionosonde measurements, show that SF over this region can most likely be attributed to travelling ionospheric disturbances (TIDs), caused by gravity waves (GWs) and neutral wind composition changes. The GWs were mostly associated with geomagnetic storms and sub-storms that occurred during periods of high and moderate solar activity (2001-2005). SF occurrence during the low solar activity period (2006-2008)can probably be attributed to neutral wind composition changes.
- Full Text:
- Authors: Amabayo, Emirant Bertillas
- Date: 2012
- Subjects: Ionosphere -- Research , Sudden ionospheric disturbances , Ionospheric storms , Solar activity , Sunspots
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5476 , http://hdl.handle.net/10962/d1005261 , Ionosphere -- Research , Sudden ionospheric disturbances , Ionospheric storms , Solar activity , Sunspots
- Description: The occurrence of mid-latitude spread F (SF) over South Africa has not been extensively studied since the installation of the DPS-4 digisondes at Madimbo (30.88◦E, 22.38◦S), Grahamstown (33.32◦S, 26.50◦E) and Louisvale (28.51◦S, 21.24◦E). This study is intended to quantify the probability of the occurrence of F region disturbances associated with ionospheric spread F (SF) and L-band scintillation over South Africa. This study used available ionosonde data for 8 years (2000-2008) from the three South African stations. The SF events were identified manually on ionograms and grouped for further statistical analysis into frequency SF (FSF), range SF (RSF) and mixed SF (MSF). The results show that the diurnal pattern of SF occurrence peaks strongly between 23:00 and 00:00 UT. This pattern is true for all seasons and types of SF at Madimbo and Grahamstown during 2001 and 2005, except for RSF which had peaks during autumn and spring during 2001 at Madimbo. The probability of both MSF and FSF tends to increase with decreasing sunspot number (SSN), with a peak in 2005 (a moderate solar activity period). The seasonal peaks of MSF and FSF are more frequent during winter months at both Madimbo and Grahamstown. In this study SF was evident in ∼ 0.03% and ∼ 0.06% of the available ionograms at Madimbo and Grahamstown respectively during the eight year period. The presence of ionospheric irregularities associated with SF and scintillation was investigated using data from selected Global Positioning System (GPS) receiver stations distributed across South Africa. The results, based on GPS total electron content (TEC) and ionosonde measurements, show that SF over this region can most likely be attributed to travelling ionospheric disturbances (TIDs), caused by gravity waves (GWs) and neutral wind composition changes. The GWs were mostly associated with geomagnetic storms and sub-storms that occurred during periods of high and moderate solar activity (2001-2005). SF occurrence during the low solar activity period (2006-2008)can probably be attributed to neutral wind composition changes.
- Full Text:
Musculoskeletal and perceptual responses of batsmen comparing high- and moderate-volume sprints between the wickets
- Authors: Sheppard, Bronwyn Jane
- Date: 2012
- Subjects: Cricket -- Batting -- Physiological aspects , Cricket injuries , Musculoskeletal system -- Wounds and injuries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5171 , http://hdl.handle.net/10962/d1016366
- Description: Background: Literature has associated repeated eccentric muscle actions with increased muscle damage of the muscles involved. Eccentric actions are typical in sports which are ‘stop-start’ in nature requiring rapid acceleration and deceleration, typical of a batting activity in cricket. Ultra-structural damage of the skeletal muscle as a consequence of repeated decelerating activities is associated with performance decrements, particularly muscle strength and sprinting speeds. This suggests that eccentric strength decrements may provide an indication for the development of muscle strain injuries during these activities. Despite these findings, limited research has identified the specific musculoskeletal demands placed on cricket batsmen, particularly with reference to various match intensities. Objective: The present study, therefore, sought to determine the specific musculoskeletal, physiological and perceptual demands placed on specialised batsmen during two work bouts of different intensities; one representing a highintensity work bout and the other a moderate-intensity work bout. The dependent variables of interest were muscle activation, isokinetic strength changes, heart rate, ‘central’ and ‘local’ ratings of perceived exertion (RPE), body discomfort and performance. Methods: The two experimental conditions, representative of a high- (HVR) and moderate-volume running (MVR) batting protocol, required players to perform a simulated batting work bout of either twelve or six runs an over, within a laboratory setting. Selected physiological, perceptual and performance measures were collected at specific time intervals throughout the work bout while the biophysical measures were collected prior to, and following both protocols. Results: Of the variables measured, heart rate, ‘central’ and ‘local’ RPE values were observed to increase significantly (p<0.05) over time. This increase was greater as a consequence of the HVR in comparison to the MVR. No change in sprint times was documented during the MVR, in contrast, significant (p<0.05) increases over time were observed during the HVR, further highlighting the elevated demands associated with this condition. In addition, an ‘end spurt’ was observed particularly following the HVR condition, suggesting athletes were conserving themselves through the adoption of a pacing strategy. Reductions in biceps femoris and semitendinosus muscle activation levels were observed following the HVR. This was further supported by the significantly greater levels of semitendinosus activation following the MVR when compared to the HVR. Peak concentric and eccentric knee extensor (EXT) (-17.17% and -16.07% respectively) and eccentric flexor (FLEX) (- 17.49%) values decreased significantly (p<0.05) following the HVR at 60°.s-1. In addition, concentric and eccentric total work produced by the flexors and eccentric extensors resulted in significantly (p<0.05) lower values due to the HVR. Conclusion: The intermittent high-volume batting work bout elicited elevated mean heart rates, perceived ratings of cardiovascular and muscular effort and sprint times. Furthermore, hamstring activation levels and muscle strength, particularly concentric strength of the dominant lower limb were negatively affected by the HVR condition. These results suggest elevated demands were placed on the hamstring musculature as a consequence of the HVR condition, indicating a greater degree of musculoskeletal strain and increased injury risk associated with running between the wickets at this intensity, representative of an aggressive batting scenario.
- Full Text:
- Authors: Sheppard, Bronwyn Jane
- Date: 2012
- Subjects: Cricket -- Batting -- Physiological aspects , Cricket injuries , Musculoskeletal system -- Wounds and injuries
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5171 , http://hdl.handle.net/10962/d1016366
- Description: Background: Literature has associated repeated eccentric muscle actions with increased muscle damage of the muscles involved. Eccentric actions are typical in sports which are ‘stop-start’ in nature requiring rapid acceleration and deceleration, typical of a batting activity in cricket. Ultra-structural damage of the skeletal muscle as a consequence of repeated decelerating activities is associated with performance decrements, particularly muscle strength and sprinting speeds. This suggests that eccentric strength decrements may provide an indication for the development of muscle strain injuries during these activities. Despite these findings, limited research has identified the specific musculoskeletal demands placed on cricket batsmen, particularly with reference to various match intensities. Objective: The present study, therefore, sought to determine the specific musculoskeletal, physiological and perceptual demands placed on specialised batsmen during two work bouts of different intensities; one representing a highintensity work bout and the other a moderate-intensity work bout. The dependent variables of interest were muscle activation, isokinetic strength changes, heart rate, ‘central’ and ‘local’ ratings of perceived exertion (RPE), body discomfort and performance. Methods: The two experimental conditions, representative of a high- (HVR) and moderate-volume running (MVR) batting protocol, required players to perform a simulated batting work bout of either twelve or six runs an over, within a laboratory setting. Selected physiological, perceptual and performance measures were collected at specific time intervals throughout the work bout while the biophysical measures were collected prior to, and following both protocols. Results: Of the variables measured, heart rate, ‘central’ and ‘local’ RPE values were observed to increase significantly (p<0.05) over time. This increase was greater as a consequence of the HVR in comparison to the MVR. No change in sprint times was documented during the MVR, in contrast, significant (p<0.05) increases over time were observed during the HVR, further highlighting the elevated demands associated with this condition. In addition, an ‘end spurt’ was observed particularly following the HVR condition, suggesting athletes were conserving themselves through the adoption of a pacing strategy. Reductions in biceps femoris and semitendinosus muscle activation levels were observed following the HVR. This was further supported by the significantly greater levels of semitendinosus activation following the MVR when compared to the HVR. Peak concentric and eccentric knee extensor (EXT) (-17.17% and -16.07% respectively) and eccentric flexor (FLEX) (- 17.49%) values decreased significantly (p<0.05) following the HVR at 60°.s-1. In addition, concentric and eccentric total work produced by the flexors and eccentric extensors resulted in significantly (p<0.05) lower values due to the HVR. Conclusion: The intermittent high-volume batting work bout elicited elevated mean heart rates, perceived ratings of cardiovascular and muscular effort and sprint times. Furthermore, hamstring activation levels and muscle strength, particularly concentric strength of the dominant lower limb were negatively affected by the HVR condition. These results suggest elevated demands were placed on the hamstring musculature as a consequence of the HVR condition, indicating a greater degree of musculoskeletal strain and increased injury risk associated with running between the wickets at this intensity, representative of an aggressive batting scenario.
- Full Text:
Negotiating family planning radio messages among Malawian rural men of traditional authority Kadewere, Chiradzulo district
- Authors: Ntaba, Jolly Maxwell
- Date: 2012
- Subjects: Family planning -- Malawi , Birth control -- Malawi , Radio advertising -- Campaigns -- Malawi , Men -- Attitudes
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3548 , http://hdl.handle.net/10962/d1018258
- Description: Family planning campaigns, using the media among other advocacy interventions, are produced and disseminated by both government and nongovernment organizations in Malawi, with an aim of reducing fertility and promotion of reproductive health. This qualitative audience study looks specifically at the reception by rural men of radio broadcast Public Service Announcements produced by the NGO, Banja La Mtsogolo, a leading provider of family planning services and products based in Blantyre. The aim of the study is to understand how the appropriation of these messages relates to traditional concepts of gender, masculinity and kinship within an area that has not been spared the influences, values and accoutrements of modernity. Underpinned by Hall’s encoding and decoding model, the study reveals that at most men make an oppositional reading of the texts based on their lived and shared cultural experiences. The results show that while people understand and appreciate the importance of family planning, cultural and traditional influences play a major role in how these messages are appropriated by and incorporated into the everyday lives of their listeners. Given the above understandings, the research asks what are the implications for the success of family-planning media campaigns by government and other non-governmental organisations such as Banja La Mtsogolo
- Full Text:
- Authors: Ntaba, Jolly Maxwell
- Date: 2012
- Subjects: Family planning -- Malawi , Birth control -- Malawi , Radio advertising -- Campaigns -- Malawi , Men -- Attitudes
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3548 , http://hdl.handle.net/10962/d1018258
- Description: Family planning campaigns, using the media among other advocacy interventions, are produced and disseminated by both government and nongovernment organizations in Malawi, with an aim of reducing fertility and promotion of reproductive health. This qualitative audience study looks specifically at the reception by rural men of radio broadcast Public Service Announcements produced by the NGO, Banja La Mtsogolo, a leading provider of family planning services and products based in Blantyre. The aim of the study is to understand how the appropriation of these messages relates to traditional concepts of gender, masculinity and kinship within an area that has not been spared the influences, values and accoutrements of modernity. Underpinned by Hall’s encoding and decoding model, the study reveals that at most men make an oppositional reading of the texts based on their lived and shared cultural experiences. The results show that while people understand and appreciate the importance of family planning, cultural and traditional influences play a major role in how these messages are appropriated by and incorporated into the everyday lives of their listeners. Given the above understandings, the research asks what are the implications for the success of family-planning media campaigns by government and other non-governmental organisations such as Banja La Mtsogolo
- Full Text:
Normative indicators for an isiXhosa-speaking population with disadvantaged education for tests of hand motor function and verbal fluency
- Authors: Da Silva Pita, Anita
- Date: 2012
- Subjects: Neuropsychological tests Hand -- Movements People with social disabilities -- Language People with social disabilities -- Education
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2959 , http://hdl.handle.net/10962/d1002468
- Description: The aim of the study was to obtain preliminary normative data for two tests of hand motor function (Successive Finger Tapping and Purdue Pegboard tests) and two tests of verbal fluency ("S"-Words-In-One-Minute and Words-In-One-Minute), administered in English, on a non-clinical sample of black, isiXhosa-speaking unskilled workers with a background of relatively disadvantaged former DET education (N = 33). The sample was equally distributed for gender; educational level was restricted to 11 - 12 years; age range was 18 - 40 years divided further into two age categories (18 - 29 and 30 - 40 years). Results of t-test comparative analyses revealed significant age effects on both trials of the Successive Finger Tapping test in the direction of the younger age group outperforming the older age group, and a marginal but consistent tendency towards poorer performance at an earlier age stage than proposed by the available literature, for the Purdue Pegboard, "S"Words- In-One-Minute and Words-In-One-Minute. Gender effects were only in evidence on the Purdue Pegboard in the direction of females outperforming males. A descriptive comparison of the norms acquired for the present study with available normative data for English first language speaking populations with higher levels and/ or relatively advantaged quality of education revealed consistently poorer performance for the present study. The findings highlight the effect of relatively low levels and/ or poor quality of education on both verbal and non-verbal neuropsychological test performance and confirm the need for demographically specific normative data.
- Full Text:
- Authors: Da Silva Pita, Anita
- Date: 2012
- Subjects: Neuropsychological tests Hand -- Movements People with social disabilities -- Language People with social disabilities -- Education
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2959 , http://hdl.handle.net/10962/d1002468
- Description: The aim of the study was to obtain preliminary normative data for two tests of hand motor function (Successive Finger Tapping and Purdue Pegboard tests) and two tests of verbal fluency ("S"-Words-In-One-Minute and Words-In-One-Minute), administered in English, on a non-clinical sample of black, isiXhosa-speaking unskilled workers with a background of relatively disadvantaged former DET education (N = 33). The sample was equally distributed for gender; educational level was restricted to 11 - 12 years; age range was 18 - 40 years divided further into two age categories (18 - 29 and 30 - 40 years). Results of t-test comparative analyses revealed significant age effects on both trials of the Successive Finger Tapping test in the direction of the younger age group outperforming the older age group, and a marginal but consistent tendency towards poorer performance at an earlier age stage than proposed by the available literature, for the Purdue Pegboard, "S"Words- In-One-Minute and Words-In-One-Minute. Gender effects were only in evidence on the Purdue Pegboard in the direction of females outperforming males. A descriptive comparison of the norms acquired for the present study with available normative data for English first language speaking populations with higher levels and/ or relatively advantaged quality of education revealed consistently poorer performance for the present study. The findings highlight the effect of relatively low levels and/ or poor quality of education on both verbal and non-verbal neuropsychological test performance and confirm the need for demographically specific normative data.
- Full Text:
On the underwater visual census of Western Indian Ocean coral reef fishes
- Authors: Wartenberg, Reece
- Date: 2012
- Subjects: Coral reef fishes -- Africa, Southern , Coral reef fishes -- Indian Ocean , Coral reef fishes -- Behavior , Fish communities -- Africa, Southern , Fish communities -- Indian Ocean , Groundfishes -- Africa, Southern , Groundfishes -- Indian Ocean , Groundfishes -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5308 , http://hdl.handle.net/10962/d1005153 , Coral reef fishes -- Africa, Southern , Coral reef fishes -- Indian Ocean , Coral reef fishes -- Behavior , Fish communities -- Africa, Southern , Fish communities -- Indian Ocean , Groundfishes -- Africa, Southern , Groundfishes -- Indian Ocean , Groundfishes -- Behavior
- Description: This study conducted the first high-resolution investigation of the ichthyofaunal assemblages on a high-latitude coral reef in the Western Indian Ocean (WIO). Two-Mile reef, in South Africa, is a large, accessible patch-reef, and was selected as a candidate study area. Although the effect of season in structuring coral reef fish communities is most-often overlooked, the relationship between these fish communities and their habitat structure has been investigated. In South Africa, however, neither of these potential community-level drivers has been explored. As coral reefs worldwide are faced with high levels of usage pressure, nondestructive underwater visual census (UVC) techniques were identified as the most appropriate survey methods. This study had two primary aims that were; (1) to identify the most suitable technique for the UVC of coral reef fishes, and to test variations of the selected technique for appropriateness to implementation in long-term monitoring programs, and (2) to determine if possible changes to ichthyofaunal community structure could be related to trends in season and/or habitat characteristics. A review of the literature indicated that the most appropriate UVC method for surveying epibenthic coral reef fishes is underwater transecting. To compare the traditional slate-based transects to variations that implement digital image technology, slate transects were compared to a first-attempt digital photographic transect technique, and digital videographic transects. Videographic transects produced the most favourable species richness, abundance, and standard deviations of the three techniques. Diversity was not significantly different between transect techniques. The minimum required sample size was lowest for videographic transects (17 replicates), intermediate for photographic transects (27 replicates) and highest for slate transects (37 replicates). Videographic and photographic transects required greater analysis time to generate counts, but required lower observer training time. While videographic transects produced the lowest proportion of species considered unidentifiable, all three transect techniques showed similar functionality to surveying epibenthic coral reef fishes. Videographic transects were therefore identified as the most appropriate UVC technique for this study. Videographic transects at shallow (6 – 14 m), intermediate (14 – 22 m) and deep (22 – 30 m) depths in mid-winter and mid-summer, sampled a total of 41 families consisting of 209 species and 18172 individuals, dominated by pomacentrids in abundance and labrids in richness. The fish assemblages on Two-Mile Reef were found to be similar in composition to lower-latitude WIO reefs. Overall ichthyofaunal abundance and richness was significantly higher in summer than in winter, and was higher at shallow sites than at intermediate and deep sites. A multivariate approach confirmed differences between seasons at shallow depths but not between seasons at intermediate and deep depths. The fish assemblages on Two-Mile Reef can therefore be described as being comprised of four relatively distinct communities: a shallow, winter community; a shallow, summer community; a year-round intermediate community; and a year-round deep community. The distributions of discriminating species indicated that high abundances of the algal-feeding pomacentrids are observed only at shallow and intermediate sites while high abundances of the zooplanktivorous serranid subfamily, the Anthiinae, are observed predominantly at deep sites. Assessment of all measured supplementary variables indicated that of all factor combinations, observed patterns could be ascribed most strongly to depth. Quantification of reef characteristics indicated that as depth increases, habitat complexity decreases, benthic communities shift from dense coral domination to sparse sponge domination, and algal biomass and cover decreases. The ability of the videographic transect technique to detect changes in community structure with season and depth indicates that season and depth should be accounted for in future high-latitude ichtyofaunal surveys, and that the videographic transect technique is suitable for implementation in long-term monitoring programs on coral reefs. The similarity in fish assemblages between Two-Mile Reef and lower latitude regions suggests that the protocol for surveying epibenthic coral reef fishes, resulting from this study, is relevant throughout the continental WIO.
- Full Text:
- Authors: Wartenberg, Reece
- Date: 2012
- Subjects: Coral reef fishes -- Africa, Southern , Coral reef fishes -- Indian Ocean , Coral reef fishes -- Behavior , Fish communities -- Africa, Southern , Fish communities -- Indian Ocean , Groundfishes -- Africa, Southern , Groundfishes -- Indian Ocean , Groundfishes -- Behavior
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5308 , http://hdl.handle.net/10962/d1005153 , Coral reef fishes -- Africa, Southern , Coral reef fishes -- Indian Ocean , Coral reef fishes -- Behavior , Fish communities -- Africa, Southern , Fish communities -- Indian Ocean , Groundfishes -- Africa, Southern , Groundfishes -- Indian Ocean , Groundfishes -- Behavior
- Description: This study conducted the first high-resolution investigation of the ichthyofaunal assemblages on a high-latitude coral reef in the Western Indian Ocean (WIO). Two-Mile reef, in South Africa, is a large, accessible patch-reef, and was selected as a candidate study area. Although the effect of season in structuring coral reef fish communities is most-often overlooked, the relationship between these fish communities and their habitat structure has been investigated. In South Africa, however, neither of these potential community-level drivers has been explored. As coral reefs worldwide are faced with high levels of usage pressure, nondestructive underwater visual census (UVC) techniques were identified as the most appropriate survey methods. This study had two primary aims that were; (1) to identify the most suitable technique for the UVC of coral reef fishes, and to test variations of the selected technique for appropriateness to implementation in long-term monitoring programs, and (2) to determine if possible changes to ichthyofaunal community structure could be related to trends in season and/or habitat characteristics. A review of the literature indicated that the most appropriate UVC method for surveying epibenthic coral reef fishes is underwater transecting. To compare the traditional slate-based transects to variations that implement digital image technology, slate transects were compared to a first-attempt digital photographic transect technique, and digital videographic transects. Videographic transects produced the most favourable species richness, abundance, and standard deviations of the three techniques. Diversity was not significantly different between transect techniques. The minimum required sample size was lowest for videographic transects (17 replicates), intermediate for photographic transects (27 replicates) and highest for slate transects (37 replicates). Videographic and photographic transects required greater analysis time to generate counts, but required lower observer training time. While videographic transects produced the lowest proportion of species considered unidentifiable, all three transect techniques showed similar functionality to surveying epibenthic coral reef fishes. Videographic transects were therefore identified as the most appropriate UVC technique for this study. Videographic transects at shallow (6 – 14 m), intermediate (14 – 22 m) and deep (22 – 30 m) depths in mid-winter and mid-summer, sampled a total of 41 families consisting of 209 species and 18172 individuals, dominated by pomacentrids in abundance and labrids in richness. The fish assemblages on Two-Mile Reef were found to be similar in composition to lower-latitude WIO reefs. Overall ichthyofaunal abundance and richness was significantly higher in summer than in winter, and was higher at shallow sites than at intermediate and deep sites. A multivariate approach confirmed differences between seasons at shallow depths but not between seasons at intermediate and deep depths. The fish assemblages on Two-Mile Reef can therefore be described as being comprised of four relatively distinct communities: a shallow, winter community; a shallow, summer community; a year-round intermediate community; and a year-round deep community. The distributions of discriminating species indicated that high abundances of the algal-feeding pomacentrids are observed only at shallow and intermediate sites while high abundances of the zooplanktivorous serranid subfamily, the Anthiinae, are observed predominantly at deep sites. Assessment of all measured supplementary variables indicated that of all factor combinations, observed patterns could be ascribed most strongly to depth. Quantification of reef characteristics indicated that as depth increases, habitat complexity decreases, benthic communities shift from dense coral domination to sparse sponge domination, and algal biomass and cover decreases. The ability of the videographic transect technique to detect changes in community structure with season and depth indicates that season and depth should be accounted for in future high-latitude ichtyofaunal surveys, and that the videographic transect technique is suitable for implementation in long-term monitoring programs on coral reefs. The similarity in fish assemblages between Two-Mile Reef and lower latitude regions suggests that the protocol for surveying epibenthic coral reef fishes, resulting from this study, is relevant throughout the continental WIO.
- Full Text:
Optimistic science: the effectiveness of economic methodology in achieving objectivity
- Authors: Holl, Ryan
- Date: 2012
- Subjects: Economics -- Methodology , Social epistemology , Knowledge, Theory of -- Science , Objectivity -- Science , Science -- Methodology , Optimism
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1105 , http://hdl.handle.net/10962/d1013393
- Description: This thesis examines the extent to which optimism has a bearing on objectivity in scientific inquiry. It is not, however, a psychological level examination into objectivity. Rather, the discussion focuses on collective attitudes, whether in the form of science or a more general public opinion. In essence, sources of optimism at the fundamental level of scientific inquiry are articulated with a careful attempt to differentiate between attitudes about the subject (methodology) and the object of study. The antithetical thread of optimism versus pessimism is teased out with the use of a joint case study of liberalism and Stalinism. The idea of antithesis, however, is contrasted by the fact that, although mirror image ideologies, these collective attitudes share a common faith in progress (albeit through different social mechanisms). This faith in progress provides the basis for the crux of the thesis as it moves to discuss scientific methodology. There is general agreement on what good science should look like and the possibility of progressive science can be articulated. However, it is also possible to highlight the conditions for degenerative science and to further link this to a degenerative social totality in which democracy and social progress are undermined. Economics is used as a case study and it is argued that dogmatic notions on progress have proved to be a major stumbling block to objectivity in the discipline. Furthermore, the implications on the real world are serious.
- Full Text:
- Authors: Holl, Ryan
- Date: 2012
- Subjects: Economics -- Methodology , Social epistemology , Knowledge, Theory of -- Science , Objectivity -- Science , Science -- Methodology , Optimism
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1105 , http://hdl.handle.net/10962/d1013393
- Description: This thesis examines the extent to which optimism has a bearing on objectivity in scientific inquiry. It is not, however, a psychological level examination into objectivity. Rather, the discussion focuses on collective attitudes, whether in the form of science or a more general public opinion. In essence, sources of optimism at the fundamental level of scientific inquiry are articulated with a careful attempt to differentiate between attitudes about the subject (methodology) and the object of study. The antithetical thread of optimism versus pessimism is teased out with the use of a joint case study of liberalism and Stalinism. The idea of antithesis, however, is contrasted by the fact that, although mirror image ideologies, these collective attitudes share a common faith in progress (albeit through different social mechanisms). This faith in progress provides the basis for the crux of the thesis as it moves to discuss scientific methodology. There is general agreement on what good science should look like and the possibility of progressive science can be articulated. However, it is also possible to highlight the conditions for degenerative science and to further link this to a degenerative social totality in which democracy and social progress are undermined. Economics is used as a case study and it is argued that dogmatic notions on progress have proved to be a major stumbling block to objectivity in the discipline. Furthermore, the implications on the real world are serious.
- Full Text:
Penumbra
- Authors: Mahlangu, Songeziwe
- Date: 2012
- Subjects: South African fiction (English) -- 21st century , Fiction -- Social aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5979 , http://hdl.handle.net/10962/d1015207
- Description: After failing his Post Graduate Diploma in Accounting Mangaliso Zolo takes an office job at a large insurance company in Cape Town. Anonymous and overlooked in a vast bureaucracy but with a pay check promising happiness and security, he slides into a series of personal crises that test his grip on what he believes in. When at his lowest ebb he leaves his job, grabs his bible and hits the streets his world closes in on him and he is eventually confined to a psychiatric hospital. Penumbra is a novel that explores the liminal area between faith and avarice, sanity and madness, modernity and tradition, friendship and enmity. It is set in contemporary South Africa, a society defined by alienation and excess.
- Full Text:
- Authors: Mahlangu, Songeziwe
- Date: 2012
- Subjects: South African fiction (English) -- 21st century , Fiction -- Social aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5979 , http://hdl.handle.net/10962/d1015207
- Description: After failing his Post Graduate Diploma in Accounting Mangaliso Zolo takes an office job at a large insurance company in Cape Town. Anonymous and overlooked in a vast bureaucracy but with a pay check promising happiness and security, he slides into a series of personal crises that test his grip on what he believes in. When at his lowest ebb he leaves his job, grabs his bible and hits the streets his world closes in on him and he is eventually confined to a psychiatric hospital. Penumbra is a novel that explores the liminal area between faith and avarice, sanity and madness, modernity and tradition, friendship and enmity. It is set in contemporary South Africa, a society defined by alienation and excess.
- Full Text:
Perceptions of commerce graduates from a selected higher education institution
- Authors: Kaliika, Michael
- Date: 2012
- Subjects: Education, Higher -- Curricula -- South Africa -- Evaluation Business education -- Curricula -- South Africa -- Evaluation Business education graduates -- South Africa -- Attitudes
- Type: Thesis , Masters , MCom
- Identifier: vital:1188 , http://hdl.handle.net/10962/d1004358
- Description: The role of higher education in developing human capital and contributing to economic growth, competitive advantage and societal progress of any country is well documented. The direct link between the economic performance of a country and the level of education of its citizens cannot be repudiated. Furthermore, the demands of a growing economy, governmental pressure and the competitive international business environment have put pressure on South African businesses. This is aggravated by a “skills crisis” and the need to deliver more goods and services to increasingly more diverse customers. There is consensus amongst experts that the shortage of skills and high-level managerial human resources in South Africa constitute a major threat to the country’s future economic development and productivity growth. As the business world becomes increasingly sophisticated and challenging, so does the need to continuously review and assess the business qualifications that equip managers to cope with the challenges facing them. The competencies that come with a Commerce degree are relevant in every corner of society from managing successful private companies, public organisations, for governments to be able to contribute to the greatest good of society, to socially effective not- for- profit organisations. Despite the importance of a degree in Commerce there are some criticisms about the degree and Commerce graduates. The problem statement of this study is therefore vested in the continuum of praise and criticisms of Commerce graduates and the Commerce curriculum and, the reported imbalances between higher education institutions and the needs of the labour market. The question is whether such praise and criticisms are justified and whether higher education institutions specifically meet the requirements and expectations of both the graduates themselves and of business practice. The primary research objective of this study was, therefore, to obtain the opinions of Commerce graduates and Commerce graduate employers on the overall perception of Commerce graduates produced by a prominent HEI in the Eastern Cape Province in South iv Africa. To achieve this objective and based on in-depth analysis of secondary sources, two independent empirical surveys, aimed at two population strata were conducted, namely: • The Commerce graduates with known email addresses (N = 1 870) were extracted from the HEI’s alumni database. A total of 231 usable questionnaires were received from these Commerce graduates. • The employers with known addresses (N = 85) were extracted from the selected HEIs Career Centre database. A total of 47 usable questionnaires were received from the employers of the Commerce graduates. The main findings in this research pertain to aspects concerning core courses in the Commerce curriculum offered by the selected HEI, management skills and traits as required in the work environment, commerce curriculum outcomes and perceived experience as a student in the Faculty of Commerce at the selected HEI and Employer perceptions on the profile of the Commerce graduate. In this regard, the main findings are therefore summarised below: • Both graduates and employers assigned high relative importance scores to seventeen of the 19 core courses, supporting the multi-functionary interdisciplinary approach to the Commerce curriculum. Concerns were expressed by the Commerce graduates with the quality of tuition they had received in most of the core courses. Likewise, employers were not always satisfied with the Commerce graduates’ proficiency in some of the core courses, relative to the importance of core courses for running a business. • The Commerce graduates and employers strongly endorsed and supported the importance of the 43 management skills and traits in the work environment. Commerce graduates expressed concerns about the extent to which their management skills and traits had been developed through tuition. Concerns about the proficiency of the Commerce graduates in all the management skills and traits, relative to the importance in the work place, were conveyed by the employers. • On average the perceptions on the outcome of studies in the Faculty of Commerce were very highly regarded by the Commerce graduates. The highest mean score was for the item “Studying in the Faculty of Commerce contributed to an increase in my knowledge and abilities.”• The perceived experience of Commerce graduates as students in the Faculty of Commerce at the selected HEI was very highly regarded, implying that the selected HEI was meeting the expectations of its Commerce graduates. • Employer perceptions of what would constitute an ideal Commerce graduate were not fully met by the profile of the actual Commerce graduate from the selected HEI.
- Full Text:
- Authors: Kaliika, Michael
- Date: 2012
- Subjects: Education, Higher -- Curricula -- South Africa -- Evaluation Business education -- Curricula -- South Africa -- Evaluation Business education graduates -- South Africa -- Attitudes
- Type: Thesis , Masters , MCom
- Identifier: vital:1188 , http://hdl.handle.net/10962/d1004358
- Description: The role of higher education in developing human capital and contributing to economic growth, competitive advantage and societal progress of any country is well documented. The direct link between the economic performance of a country and the level of education of its citizens cannot be repudiated. Furthermore, the demands of a growing economy, governmental pressure and the competitive international business environment have put pressure on South African businesses. This is aggravated by a “skills crisis” and the need to deliver more goods and services to increasingly more diverse customers. There is consensus amongst experts that the shortage of skills and high-level managerial human resources in South Africa constitute a major threat to the country’s future economic development and productivity growth. As the business world becomes increasingly sophisticated and challenging, so does the need to continuously review and assess the business qualifications that equip managers to cope with the challenges facing them. The competencies that come with a Commerce degree are relevant in every corner of society from managing successful private companies, public organisations, for governments to be able to contribute to the greatest good of society, to socially effective not- for- profit organisations. Despite the importance of a degree in Commerce there are some criticisms about the degree and Commerce graduates. The problem statement of this study is therefore vested in the continuum of praise and criticisms of Commerce graduates and the Commerce curriculum and, the reported imbalances between higher education institutions and the needs of the labour market. The question is whether such praise and criticisms are justified and whether higher education institutions specifically meet the requirements and expectations of both the graduates themselves and of business practice. The primary research objective of this study was, therefore, to obtain the opinions of Commerce graduates and Commerce graduate employers on the overall perception of Commerce graduates produced by a prominent HEI in the Eastern Cape Province in South iv Africa. To achieve this objective and based on in-depth analysis of secondary sources, two independent empirical surveys, aimed at two population strata were conducted, namely: • The Commerce graduates with known email addresses (N = 1 870) were extracted from the HEI’s alumni database. A total of 231 usable questionnaires were received from these Commerce graduates. • The employers with known addresses (N = 85) were extracted from the selected HEIs Career Centre database. A total of 47 usable questionnaires were received from the employers of the Commerce graduates. The main findings in this research pertain to aspects concerning core courses in the Commerce curriculum offered by the selected HEI, management skills and traits as required in the work environment, commerce curriculum outcomes and perceived experience as a student in the Faculty of Commerce at the selected HEI and Employer perceptions on the profile of the Commerce graduate. In this regard, the main findings are therefore summarised below: • Both graduates and employers assigned high relative importance scores to seventeen of the 19 core courses, supporting the multi-functionary interdisciplinary approach to the Commerce curriculum. Concerns were expressed by the Commerce graduates with the quality of tuition they had received in most of the core courses. Likewise, employers were not always satisfied with the Commerce graduates’ proficiency in some of the core courses, relative to the importance of core courses for running a business. • The Commerce graduates and employers strongly endorsed and supported the importance of the 43 management skills and traits in the work environment. Commerce graduates expressed concerns about the extent to which their management skills and traits had been developed through tuition. Concerns about the proficiency of the Commerce graduates in all the management skills and traits, relative to the importance in the work place, were conveyed by the employers. • On average the perceptions on the outcome of studies in the Faculty of Commerce were very highly regarded by the Commerce graduates. The highest mean score was for the item “Studying in the Faculty of Commerce contributed to an increase in my knowledge and abilities.”• The perceived experience of Commerce graduates as students in the Faculty of Commerce at the selected HEI was very highly regarded, implying that the selected HEI was meeting the expectations of its Commerce graduates. • Employer perceptions of what would constitute an ideal Commerce graduate were not fully met by the profile of the actual Commerce graduate from the selected HEI.
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Performance of defensive shares on the JSE during financial crisis: evidence from analysis of returns and volatility
- Authors: Arguile, Wayne Peter
- Date: 2012
- Subjects: Industries -- South Africa -- Finance Industries -- South Africa -- Statistics Johannesburg Stock Exchange Rational expectations (Economic theory)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1001 , http://hdl.handle.net/10962/d1002736
- Description: This study analyses whether historically defensive sectors on the JSE have – with respect to the market – proven to be defensive during the recent global financial crisis. By withstanding the shocks of market volatility, defensive industries (such as pharmaceuticals and consumer staples) are renowned for their consistent performance throughout the business cycle. Using daily data for the period 2000–2009, the study compares the descriptive statistics of sector returns before and during the crisis. The volatility of each sector relative to the market index is calculated using the CAPM beta and a simplified volatility ratio. The same comparison is extended to the conditional volatilities of each of the sectors, which is estimated using the GARCH model and two of its extensions: the EGARCH and GJR GARCH models. While no sector experienced a positive mean return during the financial crisis, Healthcare, Consumer Goods, Consumer Services and Industrials all proved less volatile than the market. Surprisingly, Telecommunications proved more volatile than the market and experienced leverage effects during the financial crisis. Since the timing of a recession is difficult to predict, defensive securities were found to be a useful investment tool for protection against adverse movements in the stock market.
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- Authors: Arguile, Wayne Peter
- Date: 2012
- Subjects: Industries -- South Africa -- Finance Industries -- South Africa -- Statistics Johannesburg Stock Exchange Rational expectations (Economic theory)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1001 , http://hdl.handle.net/10962/d1002736
- Description: This study analyses whether historically defensive sectors on the JSE have – with respect to the market – proven to be defensive during the recent global financial crisis. By withstanding the shocks of market volatility, defensive industries (such as pharmaceuticals and consumer staples) are renowned for their consistent performance throughout the business cycle. Using daily data for the period 2000–2009, the study compares the descriptive statistics of sector returns before and during the crisis. The volatility of each sector relative to the market index is calculated using the CAPM beta and a simplified volatility ratio. The same comparison is extended to the conditional volatilities of each of the sectors, which is estimated using the GARCH model and two of its extensions: the EGARCH and GJR GARCH models. While no sector experienced a positive mean return during the financial crisis, Healthcare, Consumer Goods, Consumer Services and Industrials all proved less volatile than the market. Surprisingly, Telecommunications proved more volatile than the market and experienced leverage effects during the financial crisis. Since the timing of a recession is difficult to predict, defensive securities were found to be a useful investment tool for protection against adverse movements in the stock market.
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Peripheral vision field fatigue during simulated driving : the effects of time on task and time of day on selected psychophysiological, performance and subjective responses
- Authors: Robertson, Jade Kelly
- Date: 2012 , 2012-09-22
- Subjects: Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5141 , http://hdl.handle.net/10962/d1007136 , Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Description: Worldwide, motor accidents are responsible for a large number of deaths and disabilities (Connor et al., 2001), and one of the major causes of motor accidents is driver fatigue. Although majority of drivers are aware of the dangers of fatigued driving, accidents related to this continues to contribute to a large percentage of all accidents, between 5 and 50% (Nilsson et al., 1997; Williamson et al., 2011). The purpose of the research was to establish the effect that fatigue renders on an individual’s peripheral visual field and to determine whether a decrement in driving performance occurs at the same rate as a decrement in peripheral visual performance. Fatigue was induced through time of day as well as time on task. Sixteen students from Rhodes University were recruited, subject to no previous sleep disorders, among other criteria. Each participant was required to partake in two conditions, namely a day condition (09h00–11h00) and a night condition (23h00– 01h00). Each condition consisted of a 90 minute dual task; the primary task was a tracking task, in which participants were instructed to track a white line as accurately as possible. A secondary peripheral response task was introduced, in which participants were instructed to respond as quickly as possible to the peripheral stimuli, by pressing one of two clickers located on the steering wheel. The peripheral stimuli were located at 20º, 30º and 40º visual angle. Psychophysiological, performance and subjective measures were obtained before, during and after the main task. The pre- and post-tests included core body temperature, critical flicker fusion frequency threshold, a digit span memory test, Wits Sleepiness Scale and a NASA-TLX questionnaire. The psychophysiological and performance measures of heart rate, heart rate variability, blink frequency, blink duration, lane deviation, number of saccades towards peripheral stimuli, response time to peripheral stimuli and the percentage of missed peripheral responses were all recorded throughout the 90 minute main dual task. The results revealed significant differences (p<0.05) for heart rate variability, number of saccades towards peripheral stimuli and the Wits Sleepiness Scale, with regard to time of day. For time on task, significant effects were established for lane deviation, response time to peripheral stimuli, percentage of missed peripheral responses, heart rate, heart rate variability, blink frequency, blink duration, critical flicker fusion frequency threshold, core body temperature and the Wits Sleepiness Scale. Eccentricity was analysed and found to be significant for response time to peripheral stimuli, as well as for the percentage of missed peripheral responses; there was a significant increase in both measures with an increase in the stimuli eccentricity. No significances were established for time of day or between the pre- and post-tests conducted for the digit span memory performance; however, a significant interactional effect between the two was established. When assessing the percentage rate of decrement of driving performance compared to the percentage rate in the decrement of the missed peripheral responses, it was found that the percentage rate of decrement was equal for both measures. Thus from this research it can be seen that, concurrent with a decrement in driving performance, there are adverse effects on an individuals' peripheral vision, which have great implications for the safety of workers in industry and transport, as well as motorists. It was also established that time on task is possibly a more appropriate variable to consider than time of day, when implementing work schedules and rest breaks in industry, transport and fields alike, as more significant findings were seen for time on task compared to time of day. , Adobe Acrobat 9.53 Paper Capture Plug-in
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- Authors: Robertson, Jade Kelly
- Date: 2012 , 2012-09-22
- Subjects: Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5141 , http://hdl.handle.net/10962/d1007136 , Automobile driving simulators , Automobile driving -- Psychological aspects , Automobile driving -- Physiological aspects , Traffic accidents , Traffic safety , Fatigue , Peripheral vision
- Description: Worldwide, motor accidents are responsible for a large number of deaths and disabilities (Connor et al., 2001), and one of the major causes of motor accidents is driver fatigue. Although majority of drivers are aware of the dangers of fatigued driving, accidents related to this continues to contribute to a large percentage of all accidents, between 5 and 50% (Nilsson et al., 1997; Williamson et al., 2011). The purpose of the research was to establish the effect that fatigue renders on an individual’s peripheral visual field and to determine whether a decrement in driving performance occurs at the same rate as a decrement in peripheral visual performance. Fatigue was induced through time of day as well as time on task. Sixteen students from Rhodes University were recruited, subject to no previous sleep disorders, among other criteria. Each participant was required to partake in two conditions, namely a day condition (09h00–11h00) and a night condition (23h00– 01h00). Each condition consisted of a 90 minute dual task; the primary task was a tracking task, in which participants were instructed to track a white line as accurately as possible. A secondary peripheral response task was introduced, in which participants were instructed to respond as quickly as possible to the peripheral stimuli, by pressing one of two clickers located on the steering wheel. The peripheral stimuli were located at 20º, 30º and 40º visual angle. Psychophysiological, performance and subjective measures were obtained before, during and after the main task. The pre- and post-tests included core body temperature, critical flicker fusion frequency threshold, a digit span memory test, Wits Sleepiness Scale and a NASA-TLX questionnaire. The psychophysiological and performance measures of heart rate, heart rate variability, blink frequency, blink duration, lane deviation, number of saccades towards peripheral stimuli, response time to peripheral stimuli and the percentage of missed peripheral responses were all recorded throughout the 90 minute main dual task. The results revealed significant differences (p<0.05) for heart rate variability, number of saccades towards peripheral stimuli and the Wits Sleepiness Scale, with regard to time of day. For time on task, significant effects were established for lane deviation, response time to peripheral stimuli, percentage of missed peripheral responses, heart rate, heart rate variability, blink frequency, blink duration, critical flicker fusion frequency threshold, core body temperature and the Wits Sleepiness Scale. Eccentricity was analysed and found to be significant for response time to peripheral stimuli, as well as for the percentage of missed peripheral responses; there was a significant increase in both measures with an increase in the stimuli eccentricity. No significances were established for time of day or between the pre- and post-tests conducted for the digit span memory performance; however, a significant interactional effect between the two was established. When assessing the percentage rate of decrement of driving performance compared to the percentage rate in the decrement of the missed peripheral responses, it was found that the percentage rate of decrement was equal for both measures. Thus from this research it can be seen that, concurrent with a decrement in driving performance, there are adverse effects on an individuals' peripheral vision, which have great implications for the safety of workers in industry and transport, as well as motorists. It was also established that time on task is possibly a more appropriate variable to consider than time of day, when implementing work schedules and rest breaks in industry, transport and fields alike, as more significant findings were seen for time on task compared to time of day. , Adobe Acrobat 9.53 Paper Capture Plug-in
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Perspectives on China's rise in Namibia: the effects on foreign policy and domestic politics
- Amadhila, Nelago Ndapandula Ndanyanyukwa
- Authors: Amadhila, Nelago Ndapandula Ndanyanyukwa
- Date: 2012
- Subjects: Namibia -- Relations -- China China -- Relations -- Namibia Namibia -- Politics and government -- Chinese influences Namibia -- Economic conditions -- Chinese influences
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2758 , http://hdl.handle.net/10962/d1002968
- Description: This thesis analyses the different levels at which China’s presence in Namibia affects Namibia’s domestic politics and foreign policy from a constructivist viewpoint. Constructivist theory is used to examine the different perceptions of the Chinese in Namibia and how these inform Namibian politics and Sino-Namibian relations. These perceptions are formed at different levels of society in formal and informal relations, state-to-state, state-to-business,business-to-business and individual-to-group relations. The way in which perceptions of Chinese involvement in Namibia at the grassroots level of society differ from those at the top increasingly has an effect on domestic Namibian politics and, as such, Sino-Namibian relations. This identifies official and non-official perceptions of China’s political, economic and social presence to determine the effects of grassroots on China vis-à-vis official perceptions in Namibian politics and the effects of grassroots views on Namibian politics and on official views and state behaviour towards China and China’s presence in the country.
- Full Text:
- Authors: Amadhila, Nelago Ndapandula Ndanyanyukwa
- Date: 2012
- Subjects: Namibia -- Relations -- China China -- Relations -- Namibia Namibia -- Politics and government -- Chinese influences Namibia -- Economic conditions -- Chinese influences
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2758 , http://hdl.handle.net/10962/d1002968
- Description: This thesis analyses the different levels at which China’s presence in Namibia affects Namibia’s domestic politics and foreign policy from a constructivist viewpoint. Constructivist theory is used to examine the different perceptions of the Chinese in Namibia and how these inform Namibian politics and Sino-Namibian relations. These perceptions are formed at different levels of society in formal and informal relations, state-to-state, state-to-business,business-to-business and individual-to-group relations. The way in which perceptions of Chinese involvement in Namibia at the grassroots level of society differ from those at the top increasingly has an effect on domestic Namibian politics and, as such, Sino-Namibian relations. This identifies official and non-official perceptions of China’s political, economic and social presence to determine the effects of grassroots on China vis-à-vis official perceptions in Namibian politics and the effects of grassroots views on Namibian politics and on official views and state behaviour towards China and China’s presence in the country.
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Photophysicochemical studies of phenylthio phthalocyanines interaction with gold nanoparticles and applications in dye sensitised solar cells and optical limiting
- Authors: Forteath, Shaun
- Date: 2012
- Subjects: Phthalocyanines , Nanoparticles , Photochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4334 , http://hdl.handle.net/10962/d1004995 , Phthalocyanines , Nanoparticles , Photochemistry
- Description: The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.
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- Authors: Forteath, Shaun
- Date: 2012
- Subjects: Phthalocyanines , Nanoparticles , Photochemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4334 , http://hdl.handle.net/10962/d1004995 , Phthalocyanines , Nanoparticles , Photochemistry
- Description: The syntheses, spectroscopic characterisation, photophysical and photochemical studies have been conducted for a variety of phenylthio substituted phthalocyanines (Pcs). Comparisons have been made taking into consideration the influence of the central metal ion, solvent properties and substituent type. The optical limiting properties were also determined for all the Pcs synthesised. A low-symmetry metallophthalocyanine complex was similarly characterised and the photoelectrochemical parameters determined when used as a sensitiser of nanoporous ZnO. The symmetric analogue was conjugated to gold nanoparticles to determine the influence of interactions on its photophysical properties and distinct differences occurred in the absorption and fluorescence spectra suggesting successful formation of conjugates.
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Post-apartheid racial integration in Grahamstown : a time-geographical perspective
- Authors: Irvine, Philippa Margaret
- Date: 2012
- Subjects: Race discrimination -- South Africa -- Eastern Cape Grahamstown (South Africa) -- Race relations Grahamstown (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4845 , http://hdl.handle.net/10962/d1005521
- Description: This research is situated within the context of the post-apartheid era in South Africa, which includes the dominant ideologies and policies that have shaped the urban landscape of the past and present. It investigates the extent and patterns of integration that exist twenty years after the country’s political transition and it uses Grahamstown, a small education and cultural centre in the Eastern Cape Province, as its case study. The investigation incorporates the traditional geographical focus of residential and educational integration, using conventional means of investigation such as segregation indices, dissimilarity indices, percentages and maps. However, in identifying the broader nature of ‘segregation’ and ‘integration’, the study moves beyond these foci and approaches. It adopts the timegeographical framework to reveal the dynamic use of urban space that reflects the lived space of selected individuals from the community of Grahamstown: the extent and patterns of their behavioural integration or spatial linkages. Together, these approaches reveal that Grahamstown is still a city divided by race and, now, class. Schools and residential areas remain tied to the apartheid divisions of race and the white community exists almost entirely within the bounds of apartheid’s blueprint of urban space. Rhodes University, which is located within Grahamstown, has experienced admirable levels of integration within the student body and within the staff as a whole, but not within the staff’s different levels. In essence, where integration has occurred it has been unidirectional with the black community moving into the spaces and institutions formerly reserved for whites. The limited behavioural integration or spatial linkages are shown to be tied to city structure and, within the white group, to perceptions of ‘otherness’ held by the individuals interviewed. While the study shows limited differences in the time-spatial movements between members of different races who are resident in the former white group area, it highlights the differences between those more permanently resident in the city and the temporary educational migrants or students. The study argues that the slow pace of change is related to the nature of South Africa’s democratic transition and its attending political and economic policies.
- Full Text:
- Authors: Irvine, Philippa Margaret
- Date: 2012
- Subjects: Race discrimination -- South Africa -- Eastern Cape Grahamstown (South Africa) -- Race relations Grahamstown (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4845 , http://hdl.handle.net/10962/d1005521
- Description: This research is situated within the context of the post-apartheid era in South Africa, which includes the dominant ideologies and policies that have shaped the urban landscape of the past and present. It investigates the extent and patterns of integration that exist twenty years after the country’s political transition and it uses Grahamstown, a small education and cultural centre in the Eastern Cape Province, as its case study. The investigation incorporates the traditional geographical focus of residential and educational integration, using conventional means of investigation such as segregation indices, dissimilarity indices, percentages and maps. However, in identifying the broader nature of ‘segregation’ and ‘integration’, the study moves beyond these foci and approaches. It adopts the timegeographical framework to reveal the dynamic use of urban space that reflects the lived space of selected individuals from the community of Grahamstown: the extent and patterns of their behavioural integration or spatial linkages. Together, these approaches reveal that Grahamstown is still a city divided by race and, now, class. Schools and residential areas remain tied to the apartheid divisions of race and the white community exists almost entirely within the bounds of apartheid’s blueprint of urban space. Rhodes University, which is located within Grahamstown, has experienced admirable levels of integration within the student body and within the staff as a whole, but not within the staff’s different levels. In essence, where integration has occurred it has been unidirectional with the black community moving into the spaces and institutions formerly reserved for whites. The limited behavioural integration or spatial linkages are shown to be tied to city structure and, within the white group, to perceptions of ‘otherness’ held by the individuals interviewed. While the study shows limited differences in the time-spatial movements between members of different races who are resident in the former white group area, it highlights the differences between those more permanently resident in the city and the temporary educational migrants or students. The study argues that the slow pace of change is related to the nature of South Africa’s democratic transition and its attending political and economic policies.
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Professional women balancing work and motherhood : a study of coping strategies used in balancing this dual role
- Authors: Gunton, Andrea
- Date: 2012
- Subjects: Working mothers -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Role conflict Stress (Psychology) Working mothers -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3143 , http://hdl.handle.net/10962/d1007242
- Description: The aim of this qualitative research study is to develop insights into the dynamics involved in work- family conflict, balance and coping strategies. The study explores the experiences of seven professional women, who are also mothers, employed in professional work positions in Grahamstown. The research is interpretive in nature as it aims to explore the conflicts experienced by the professional mothers in balancing their competing roles. The study focused on the demands that these women face and the coping strategies that these working mothers develop and use, in order to balance their career aspirations as well as their family responsibilities. It set out to explore the women’s perceptions of work- family conflict and the extent to which they experience it, further examining the compromises that the women have had to make and possible feelings of guilt or regret that they may have experienced. The findings indicated that this balance is sensitive to many facilitating and hindering factors. The participants revealed that they experience work- family conflict, and that the experience of it has largely to do with the guilt of not spending enough time with their family. Another significant finding was that the women expressed their coping strategies as being organised; forming a line between work and family life as well as employing domestic workers. The women further stated that there are constant compromises that have to be made to fit in the multiple roles, and that feelings of guilt and/or regret do set in at times.
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- Authors: Gunton, Andrea
- Date: 2012
- Subjects: Working mothers -- South Africa -- Grahamstown Work and family -- South Africa -- Grahamstown Role conflict Stress (Psychology) Working mothers -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3143 , http://hdl.handle.net/10962/d1007242
- Description: The aim of this qualitative research study is to develop insights into the dynamics involved in work- family conflict, balance and coping strategies. The study explores the experiences of seven professional women, who are also mothers, employed in professional work positions in Grahamstown. The research is interpretive in nature as it aims to explore the conflicts experienced by the professional mothers in balancing their competing roles. The study focused on the demands that these women face and the coping strategies that these working mothers develop and use, in order to balance their career aspirations as well as their family responsibilities. It set out to explore the women’s perceptions of work- family conflict and the extent to which they experience it, further examining the compromises that the women have had to make and possible feelings of guilt or regret that they may have experienced. The findings indicated that this balance is sensitive to many facilitating and hindering factors. The participants revealed that they experience work- family conflict, and that the experience of it has largely to do with the guilt of not spending enough time with their family. Another significant finding was that the women expressed their coping strategies as being organised; forming a line between work and family life as well as employing domestic workers. The women further stated that there are constant compromises that have to be made to fit in the multiple roles, and that feelings of guilt and/or regret do set in at times.
- Full Text: