Estimating the population size of three large carnivore species and the diet of six large carnivore species, in Madikwe Game Reserve
- Authors: Honiball, Terry-Lee
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Carnivores
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52139 , vital:43421
- Description: Large carnivores play a vital role in ecosystems, providing ecosystem services such as herbivore regulation. If not properly monitored, carnivores could place significant pressure on certain prey species, and in extreme cases, result in the local extinction of certain species. A lack of demographic data can indirectly threaten carnivores, as policies and management decisions based on demographic data can result in the over harvesting or unsustainable hunting of large carnivores. Furthermore, their conservation is becoming confined to small, fenced, protected areas. Whereby species are intensively managed, making demographic and ecological data a fundamental part of conservation decisions. Therefore, it is essential for conservation practitioners to understand large carnivore demography and their role, to conserve them effectively. To provide Madikwe Game Reserve with the necessary data for effective long-term monitoring and management of the large carnivore guild, I estimated the population size of the cryptic carnivores. I then investigated the efficacy of different camera trap survey designs on improving the detection probability of leopard (Panthera pardus), brown hyaena (Parahyaena brunnea), and spotted hyaena (Crocuta crocuta). I found that brown hyaena and spotted hyaena detection probability increased with a higher number of camera traps, whereas leopard detection probability did not increase with an increased number of camera traps. I further investigated the diet, prey preferences and dietary overlap of lion (Panthera leo), cheetah (Acinonyx jubatus), African wild dog (Lycaon pictus), leopard, spotted hyaena and brown hyaena. I found that all species displayed a degree of dietary overlap, however the most notable level of competition occurred between leopards, wild dogs, and cheetahs. This iv information will assist MGR to make informed decisions about large carnivore management in the reserve. I recommend continued long-term monitoring for the establishment of trends over time, allowing for holistic management of the entire large carnivore guild. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Honiball, Terry-Lee
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Carnivores
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52139 , vital:43421
- Description: Large carnivores play a vital role in ecosystems, providing ecosystem services such as herbivore regulation. If not properly monitored, carnivores could place significant pressure on certain prey species, and in extreme cases, result in the local extinction of certain species. A lack of demographic data can indirectly threaten carnivores, as policies and management decisions based on demographic data can result in the over harvesting or unsustainable hunting of large carnivores. Furthermore, their conservation is becoming confined to small, fenced, protected areas. Whereby species are intensively managed, making demographic and ecological data a fundamental part of conservation decisions. Therefore, it is essential for conservation practitioners to understand large carnivore demography and their role, to conserve them effectively. To provide Madikwe Game Reserve with the necessary data for effective long-term monitoring and management of the large carnivore guild, I estimated the population size of the cryptic carnivores. I then investigated the efficacy of different camera trap survey designs on improving the detection probability of leopard (Panthera pardus), brown hyaena (Parahyaena brunnea), and spotted hyaena (Crocuta crocuta). I found that brown hyaena and spotted hyaena detection probability increased with a higher number of camera traps, whereas leopard detection probability did not increase with an increased number of camera traps. I further investigated the diet, prey preferences and dietary overlap of lion (Panthera leo), cheetah (Acinonyx jubatus), African wild dog (Lycaon pictus), leopard, spotted hyaena and brown hyaena. I found that all species displayed a degree of dietary overlap, however the most notable level of competition occurred between leopards, wild dogs, and cheetahs. This iv information will assist MGR to make informed decisions about large carnivore management in the reserve. I recommend continued long-term monitoring for the establishment of trends over time, allowing for holistic management of the entire large carnivore guild. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
Evolutionary robotics controllers with location perception facilitated by neural network-based simulators
- Authors: Phillips, Antin Paul
- Date: 2021-04
- Subjects: Evolutionary Robots -- South Africa , Neural networks (Computer science) -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61613 , vital:71474
- Description: Humans impressively maintain a real-time approximation of their bodily form. For instance, one knows where one’s arm is, relative to the body, without needing to directly observe it. This ability, in part, allows humans to interact with the environment without direct observation. This bodily sense is referred to as ”proprioception“. The human body contains various proprioceptors, sensory neurons which provide information about the physical state of the body. This information, along with internal body representations that humans develop over time, allows one to maintain an approximation of their bodily form. Humans also possess an impressive sense of direction and navigation ability. For instance, a blindfolded human can move around a familiar environment and maintain an approximate sense of where they are within that environment. This ability is, in part, enabled by proprioception as it provides one with an approximation of the effects their actions have on their body. The field of Evolutionary Robots (ER) makes extensive use of robotic simulators to carry out simulated robotic evaluations. Research has been conducted into alternate forms of simulation and Simulator Neural Networks (SNNs) were subsequently developed. The speed and accuracy of these SNNs, relative to more typical simulation techniques, is what inspired the approach explored in this research. Robots do not necessarily possess the appropriate hardware to sense their position within an environment. Thus, it was proposed that SNNs could be incorporated into ER controllers to approximate the position of the robot. These SNNs would be executed in parallel to the robot and provide a constant approximation of the robot’s position. This would provide controllers with information that they would not otherwise have, albeit approximate information. Various experiments were carried out which examined both typical ER controllers as well as those which were augmented in the proposed fashion. The augmented controllers were found to outperform typical controllers as well as develop more advanced and efficient behaviours. Furthermore, the augmented controllers demonstrated the ability to solve tasks that regular controllers could not. A potential criticism of the approach suggested in this research is that ER controllers could hypothetically be trained in such a way that the proposed augmentation would be unnecessary. This possibility was investigated and it was found that successfully training controllers in such a manner would be unlikely. Furthermore, the effort involved in fine-tuning this training process would be greater than simply following the approach suggested in this research. Another potential drawback of the suggested approach involved the accuracy of the information that SNNs could provide to controllers. The approximated information was found to diverge over time and negatively affected controller performance. A method to address this issue was proposed and subsequently implemented. This method was demonstrated to be an effective means of reducing the divergence of the SNNs outputs and, in turn, improved controller performance. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Phillips, Antin Paul
- Date: 2021-04
- Subjects: Evolutionary Robots -- South Africa , Neural networks (Computer science) -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/61613 , vital:71474
- Description: Humans impressively maintain a real-time approximation of their bodily form. For instance, one knows where one’s arm is, relative to the body, without needing to directly observe it. This ability, in part, allows humans to interact with the environment without direct observation. This bodily sense is referred to as ”proprioception“. The human body contains various proprioceptors, sensory neurons which provide information about the physical state of the body. This information, along with internal body representations that humans develop over time, allows one to maintain an approximation of their bodily form. Humans also possess an impressive sense of direction and navigation ability. For instance, a blindfolded human can move around a familiar environment and maintain an approximate sense of where they are within that environment. This ability is, in part, enabled by proprioception as it provides one with an approximation of the effects their actions have on their body. The field of Evolutionary Robots (ER) makes extensive use of robotic simulators to carry out simulated robotic evaluations. Research has been conducted into alternate forms of simulation and Simulator Neural Networks (SNNs) were subsequently developed. The speed and accuracy of these SNNs, relative to more typical simulation techniques, is what inspired the approach explored in this research. Robots do not necessarily possess the appropriate hardware to sense their position within an environment. Thus, it was proposed that SNNs could be incorporated into ER controllers to approximate the position of the robot. These SNNs would be executed in parallel to the robot and provide a constant approximation of the robot’s position. This would provide controllers with information that they would not otherwise have, albeit approximate information. Various experiments were carried out which examined both typical ER controllers as well as those which were augmented in the proposed fashion. The augmented controllers were found to outperform typical controllers as well as develop more advanced and efficient behaviours. Furthermore, the augmented controllers demonstrated the ability to solve tasks that regular controllers could not. A potential criticism of the approach suggested in this research is that ER controllers could hypothetically be trained in such a way that the proposed augmentation would be unnecessary. This possibility was investigated and it was found that successfully training controllers in such a manner would be unlikely. Furthermore, the effort involved in fine-tuning this training process would be greater than simply following the approach suggested in this research. Another potential drawback of the suggested approach involved the accuracy of the information that SNNs could provide to controllers. The approximated information was found to diverge over time and negatively affected controller performance. A method to address this issue was proposed and subsequently implemented. This method was demonstrated to be an effective means of reducing the divergence of the SNNs outputs and, in turn, improved controller performance. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-04
Evolutionary robotics controllers with location perception facilitated by neural network-based simulators
- Authors: Phillips, Antin Paul
- Date: 2021-04
- Subjects: Grahamstown (South Africa) , Eastern Cape (South Africa) , Neural networks (Computer science) -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52137 , vital:43444
- Description: Humans impressively maintain a real-time approximation of their bodily form. For instance, one knows where one’s arm is, relative to the body, without needing to directly observe it. This ability, in part, allows humans to interact with the environment without direct observation. This bodily sense is referred to as ”proprioception“. The human body contains various proprioceptors, sensory neurons which provide information about the physical state of the body. This information, along with internal body representations that humans develop over time, allows one to maintain an approximation of their bodily form. Humans also possess an impressive sense of direction and navigation ability. For instance, a blindfolded human can move around a familiar environment and maintain an approximate sense of where they are within that environment. This ability is, in part, enabled by proprioception as it provides one with an approximation of the effects their actions have on their body. The field of Evolutionary Robots (ER) makes extensive use of robotic simulators to carry out simulated robotic evaluations. Research has been conducted into alternate forms of simulation and Simulator Neural Networks (SNNs) were subsequently developed. The speed and accuracy of these SNNs, relative to more typical simulation techniques, is what inspired the approach explored in this research. Robots do not necessarily possess the appropriate hardware to sense their position within an environment. Thus, it was proposed that SNNs could be incorporated into ER controllers to approximate the position of the robot. These SNNs would be executed in parallel to the robot and provide a constant approximation of the robot’s position. This would provide controllers with information that they would not otherwise have, albeit approximate information. Various experiments were carried out which examined both typical ER controllers as well as those which were augmented in the proposed fashion. The augmented controllers were found to outperform typical controllers as well as develop more advanced and efficient behaviours. Furthermore, the augmented controllers demonstrated the ability to solve tasks that regular controllers could not. A potential criticism of the approach suggested in this research is that ER controllers could hypothetically be trained in such a way that the proposed augmentation would be unnecessary. This possibility was investigated and it was found that successfully training controllers in such a manner would be unlikely. Furthermore, the effort involved in fine-tuning this training process would be greater than simply following the approach suggested in this research. Another potential drawback of the suggested approach involved the accuracy of the information that SNNs could provide to controllers. The approximated information was found to diverge over time and negatively affected controller performance. A method to address this issue was proposed and subsequently implemented. This method was demonstrated to be an effective means of reducing the divergence of the SNNs outputs and, in turn, improved controller performance. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Phillips, Antin Paul
- Date: 2021-04
- Subjects: Grahamstown (South Africa) , Eastern Cape (South Africa) , Neural networks (Computer science) -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52137 , vital:43444
- Description: Humans impressively maintain a real-time approximation of their bodily form. For instance, one knows where one’s arm is, relative to the body, without needing to directly observe it. This ability, in part, allows humans to interact with the environment without direct observation. This bodily sense is referred to as ”proprioception“. The human body contains various proprioceptors, sensory neurons which provide information about the physical state of the body. This information, along with internal body representations that humans develop over time, allows one to maintain an approximation of their bodily form. Humans also possess an impressive sense of direction and navigation ability. For instance, a blindfolded human can move around a familiar environment and maintain an approximate sense of where they are within that environment. This ability is, in part, enabled by proprioception as it provides one with an approximation of the effects their actions have on their body. The field of Evolutionary Robots (ER) makes extensive use of robotic simulators to carry out simulated robotic evaluations. Research has been conducted into alternate forms of simulation and Simulator Neural Networks (SNNs) were subsequently developed. The speed and accuracy of these SNNs, relative to more typical simulation techniques, is what inspired the approach explored in this research. Robots do not necessarily possess the appropriate hardware to sense their position within an environment. Thus, it was proposed that SNNs could be incorporated into ER controllers to approximate the position of the robot. These SNNs would be executed in parallel to the robot and provide a constant approximation of the robot’s position. This would provide controllers with information that they would not otherwise have, albeit approximate information. Various experiments were carried out which examined both typical ER controllers as well as those which were augmented in the proposed fashion. The augmented controllers were found to outperform typical controllers as well as develop more advanced and efficient behaviours. Furthermore, the augmented controllers demonstrated the ability to solve tasks that regular controllers could not. A potential criticism of the approach suggested in this research is that ER controllers could hypothetically be trained in such a way that the proposed augmentation would be unnecessary. This possibility was investigated and it was found that successfully training controllers in such a manner would be unlikely. Furthermore, the effort involved in fine-tuning this training process would be greater than simply following the approach suggested in this research. Another potential drawback of the suggested approach involved the accuracy of the information that SNNs could provide to controllers. The approximated information was found to diverge over time and negatively affected controller performance. A method to address this issue was proposed and subsequently implemented. This method was demonstrated to be an effective means of reducing the divergence of the SNNs outputs and, in turn, improved controller performance. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text: false
- Date Issued: 2021-04
Factors affecting the performance of the wooden furniture manufacturing industry in the Southern Cape
- Authors: Vheriwa, Prayer
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Furniture making -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52017 , vital:43449
- Description: The furniture manufacturing industry in South Africa is facing several challenges that affect the performance of firms in this sector. A literature review indicates several factors such as availability of resources; location; access to local markets; access to export markets; and development programmes that may affect the performance of wooden furniture manufacturing firms in the Southern Cape. The purpose of the current study was to fill the knowledge gap on why the performance of wooden furniture manufacturing firms in the Southern Cape has declined. The study intends to contribute to the limited formal information resources on the Southern Cape furniture manufacturing industry. A conceptual framework was developed and employed for investigating factors hypothesised to affect the performance of furniture manufacturing firms in the Southern Cape. The research conducted was explorative. An interpretive paradigm was selected to collect and interpret qualitative data and a positivist paradigm was used for the quantitative component of the study. The quantitative data was subjected to a chi-square test using IBM SPSS statistics software and qualitative data was analysed for meanings and context using ATLAS.ti software. Statistical tests on qualitative and quantitative data were conducted to determine whether sufficient evidence existed to make conclusions on the hypotheses, relating to significant relationships between the selected independent variables for the study and the performance of wooden furniture manufacturing firms in the Southern Cape. The results show that existing development programmes and availability of resources, namely: timber, skilled human resources and availability of finance, influence the performance of furniture manufacturing firms in the Southern Cape. Results further reveal that location; access to local market; and access to export market have a partial influence on the performance of the furniture manufacturing firms in the Southern Cape. The study presents information which serves to improve the capacity for growth of wooden furniture manufacturing firms. Based on the results, recommendations were made to overcome the factors affecting the performance of the furniture manufacturing firms in the Southern Cape. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Vheriwa, Prayer
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Furniture making -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52017 , vital:43449
- Description: The furniture manufacturing industry in South Africa is facing several challenges that affect the performance of firms in this sector. A literature review indicates several factors such as availability of resources; location; access to local markets; access to export markets; and development programmes that may affect the performance of wooden furniture manufacturing firms in the Southern Cape. The purpose of the current study was to fill the knowledge gap on why the performance of wooden furniture manufacturing firms in the Southern Cape has declined. The study intends to contribute to the limited formal information resources on the Southern Cape furniture manufacturing industry. A conceptual framework was developed and employed for investigating factors hypothesised to affect the performance of furniture manufacturing firms in the Southern Cape. The research conducted was explorative. An interpretive paradigm was selected to collect and interpret qualitative data and a positivist paradigm was used for the quantitative component of the study. The quantitative data was subjected to a chi-square test using IBM SPSS statistics software and qualitative data was analysed for meanings and context using ATLAS.ti software. Statistical tests on qualitative and quantitative data were conducted to determine whether sufficient evidence existed to make conclusions on the hypotheses, relating to significant relationships between the selected independent variables for the study and the performance of wooden furniture manufacturing firms in the Southern Cape. The results show that existing development programmes and availability of resources, namely: timber, skilled human resources and availability of finance, influence the performance of furniture manufacturing firms in the Southern Cape. Results further reveal that location; access to local market; and access to export market have a partial influence on the performance of the furniture manufacturing firms in the Southern Cape. The study presents information which serves to improve the capacity for growth of wooden furniture manufacturing firms. Based on the results, recommendations were made to overcome the factors affecting the performance of the furniture manufacturing firms in the Southern Cape. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
Fish ecology and ecophysiology in an anthropogenically-altered temporarily open/closed estuary in the warm-temperate region of the Eastern Cape Province, South Africa
- Authors: Mpinga, Mfundo
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Fishes--Ecology--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52122 , vital:43431
- Description: Estuaries are globally recognized for their contribution to the coastal marine environment by acting as nursery grounds for numerous marine estuarine-dependent fish species. These linking ecosystems between marine and riverine environments, are ideal for these species due to the habitat diversity, nutrient and food availability, shallower and calmer environments they provide relative to the ocean. Abrupt hydrodynamic and physico-chemical changes which frequently occur in estuaries impose physiological stress and requires superior adaptability in the fish that reside within them. This is exacerbated by anthropogenic modifications to estuaries which affects their natural ecological function. The Seekoei Estuary is one of 192 temporarily open/closed estuaries (TOCEs) in South Africa and these estuaries are characterised by their periodical connection to the sea due to the formation of a mouth berm. These estuaries are the dominant type in South Africa. A lot of research has been done in these kinds of estuaries, however, it is still limited due to their vast numbers. These estuaries are popular for human settlement and this has led to mismanagement due to the lack of ecological information. Furthermore, because of their inability to continuously flush out water, temporarily open closed estuaries are more vulnerable to pollution and anthropogenic modifications. The aim of this study was to assess the small fish community in relation to their environment in the hypersaline anthropogenically-altered Seekoei Estuary, by analysing the spatio-temporal trends of physico-chemical properties, nutrient loads, phytoplankton biomass and fish community structure. In addition, histological adaptation in gills of fish that survive hypersaline water was investigated. The study found that physico-chemical properties were influenced by anthropogenic alterations, in particular adverse water abstraction, instream water obstructions and artificial breaching. Nutrient concentration was found to be influenced by the intense agricultural practices in the upper reaches. It was evident that nutrient concentration (dissolved inorganic phosphorus) coupled with high salinity and optimum temperature (15 oC - 20 oC) affected the phytoplankton biomass. This estuary’s inability to naturally breach makes it vulnerable to phytoplankton blooms. The accumulation of cohesive silt caused by low river inflow, due to water abstraction in the upper reaches, was attributed to this estuary’s prolonged mouth closure. This was exacerbated by the presence of the causeway, which acts as a barrier between the middle and lower estuary. The abundance of marine fish species in the estuary, despite its long closure, indicates that the larvae and juveniles of these species make use of overwash events and brief artificial breaching events to recruit into the estuary. The high species richness in iii sites below the causeway is indicative of the barrier effect, which prevents the migration of some species to the upper reaches. This was evident during a massive fish kill, recorded during this study, which was more severe in sites below the causeway than above it. Chloride cell hyperplasia, mucus secretion and thickening of the epithelial layer in gills of indicator fish species from this estuary was the histological adaptation, which enables these fishes to be tolerant to high salinity. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Mpinga, Mfundo
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Fishes--Ecology--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52122 , vital:43431
- Description: Estuaries are globally recognized for their contribution to the coastal marine environment by acting as nursery grounds for numerous marine estuarine-dependent fish species. These linking ecosystems between marine and riverine environments, are ideal for these species due to the habitat diversity, nutrient and food availability, shallower and calmer environments they provide relative to the ocean. Abrupt hydrodynamic and physico-chemical changes which frequently occur in estuaries impose physiological stress and requires superior adaptability in the fish that reside within them. This is exacerbated by anthropogenic modifications to estuaries which affects their natural ecological function. The Seekoei Estuary is one of 192 temporarily open/closed estuaries (TOCEs) in South Africa and these estuaries are characterised by their periodical connection to the sea due to the formation of a mouth berm. These estuaries are the dominant type in South Africa. A lot of research has been done in these kinds of estuaries, however, it is still limited due to their vast numbers. These estuaries are popular for human settlement and this has led to mismanagement due to the lack of ecological information. Furthermore, because of their inability to continuously flush out water, temporarily open closed estuaries are more vulnerable to pollution and anthropogenic modifications. The aim of this study was to assess the small fish community in relation to their environment in the hypersaline anthropogenically-altered Seekoei Estuary, by analysing the spatio-temporal trends of physico-chemical properties, nutrient loads, phytoplankton biomass and fish community structure. In addition, histological adaptation in gills of fish that survive hypersaline water was investigated. The study found that physico-chemical properties were influenced by anthropogenic alterations, in particular adverse water abstraction, instream water obstructions and artificial breaching. Nutrient concentration was found to be influenced by the intense agricultural practices in the upper reaches. It was evident that nutrient concentration (dissolved inorganic phosphorus) coupled with high salinity and optimum temperature (15 oC - 20 oC) affected the phytoplankton biomass. This estuary’s inability to naturally breach makes it vulnerable to phytoplankton blooms. The accumulation of cohesive silt caused by low river inflow, due to water abstraction in the upper reaches, was attributed to this estuary’s prolonged mouth closure. This was exacerbated by the presence of the causeway, which acts as a barrier between the middle and lower estuary. The abundance of marine fish species in the estuary, despite its long closure, indicates that the larvae and juveniles of these species make use of overwash events and brief artificial breaching events to recruit into the estuary. The high species richness in iii sites below the causeway is indicative of the barrier effect, which prevents the migration of some species to the upper reaches. This was evident during a massive fish kill, recorded during this study, which was more severe in sites below the causeway than above it. Chloride cell hyperplasia, mucus secretion and thickening of the epithelial layer in gills of indicator fish species from this estuary was the histological adaptation, which enables these fishes to be tolerant to high salinity. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
Impact of feeding milk once-a-day on growth and development of jersey calves
- Authors: Myburgh, Albertus Petrus
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Calves -- Feeding and feeds
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52095 , vital:43438
- Description: In conventional calf rearing systems calves are fed milk twice a day. Calves are normally housed in a calf shed, kept in individual pens or in groups. The goal should be to limit mor-talities to less than 5% from birth to 30 days. This can be achieved by reducing animal stress, controlling diseases and feeding the animals properly. The immune function can be de-pressed by inadequate nutrition which will increase susceptibility to diseases. Key objective on a dairy farm should be to rear a healthy calf until the calf reaches the optimum mating weight. Digestive disorders and respiratory diseases are the main causes of mortalities of young calves. Jersey calves at Outeniqua Research Farm are kept in movable hutches out-side, for 8 weeks and whole milk is fed only once a day. Although it is common practice to feed milk to calves twice-a-day, Jersey calves are raised with great success by feeding whole milk once-a-day, but proven data was never collected to indicate that feeding whole milk to Jersey calves does not compromise growth or development of calves. Much research was done on feeding of milk to Holstein calves, but little was done on Jersey calves. Research also shows results on feeding of milk replacer rather than whole milk. This raised the question of can whole milk be fed once-a-day successfully to Jersey calves with-out compromising growth and development and what are the advantages of feeding whole milk once-a-day to Jersey calves? , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Myburgh, Albertus Petrus
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Calves -- Feeding and feeds
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52095 , vital:43438
- Description: In conventional calf rearing systems calves are fed milk twice a day. Calves are normally housed in a calf shed, kept in individual pens or in groups. The goal should be to limit mor-talities to less than 5% from birth to 30 days. This can be achieved by reducing animal stress, controlling diseases and feeding the animals properly. The immune function can be de-pressed by inadequate nutrition which will increase susceptibility to diseases. Key objective on a dairy farm should be to rear a healthy calf until the calf reaches the optimum mating weight. Digestive disorders and respiratory diseases are the main causes of mortalities of young calves. Jersey calves at Outeniqua Research Farm are kept in movable hutches out-side, for 8 weeks and whole milk is fed only once a day. Although it is common practice to feed milk to calves twice-a-day, Jersey calves are raised with great success by feeding whole milk once-a-day, but proven data was never collected to indicate that feeding whole milk to Jersey calves does not compromise growth or development of calves. Much research was done on feeding of milk to Holstein calves, but little was done on Jersey calves. Research also shows results on feeding of milk replacer rather than whole milk. This raised the question of can whole milk be fed once-a-day successfully to Jersey calves with-out compromising growth and development and what are the advantages of feeding whole milk once-a-day to Jersey calves? , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
Incidence of parasitic trematodes effects on the energetics and behaviour of Coryogalops sordidus (Family: Gobiidae) resident in microbialite pools, warm temperate South Africa
- Authors: Du Toit, Hendrik Daniël
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Gobiidae -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52458 , vital:43666
- Description: Coryogalops sordidus(Epaulette goby), is a cryptobenthic species of the Family Gobiidae that iscommonly foundoccupying turbulent surf zones, calm rock pools, and sand and mud flats, where they are generally carnivorous predators. The distribution of C. sordidushas been recorded for Kenya, Tanzania, Mozambique, and South Africa. The species is also resident in the microbialite pools on the temperate south east coast of South Africa. Recent reports indicated these gobies to be covered in numerous dark lesions, possibly suggesting that the microbialite pools are a sub-optimal habitat. Preliminary analyses have indicated that the dark lesions are a result of encysted metacercaria of a digenetic trematode (fluke). There werehowever,no current recorded parasiticspecies occurring within microbialite pool nor any records of any parasitic species utilizingC. sordidus as a host in South Africa. Therefore, the aim of this study was to investigate parasite-host interactions and parasite presence in and around themicrobialite pool systems of Algoa Bay using C. sordidusas a study species. Coryogalops sordiduswas identified to be parasitised by digenetic trematode metacercaria of the Family Diplostomidae Poirier, 1886, localised primarily to the host musculature, fins, eyes, and integument with no settlement on any of the visceral organs. Furthermore, C. sordidus was found additionally parasitised by a green leech (Class: Hirundinea) of the Family Piscicolidae Johnston, 1865, localised exclusively to the ventral body surface, underneath the pelvic fin of the host. Further investigation into the life cycle of the trematode, suggested that the most probable final hosts wereherons,namely Ardea cinereaand Egretta garzetta garzetta, and intermediate host likely being the freshwater gastropod Assimineacf.capensis, present inthe upper microbialite pools. In both the microbialite and neighbouring rock pools trematode prevalence was found to oscillate in response to seasonal chemical and climatic conditions, whereas the secondary piscicolid leech parasite was influencedmoreby host presence than environmental conditions. Greater prevalence and intensity were measured in the microbialite pools suggesting that these systems likely contained a suit of favourable conditions that allowed for greater trematode loads to be maintained as compared to neighbouring rock pools. As parasites often have deleterious effects on their hosts, the response can manifest as an altered host behaviour or an increased energetic debt due to elevated immune response activity and the associated cost of tissue repair at sites of parasite aggregation.This study further investigatedifgobies (C. sordidus) infected with metacercarial cysts display higher metabolic ratesordifferent swimming behaviour compared to non-infected individuals. The results indicated that the metacercarial load carried by infected hosts had on average no significant impact on energetics, swimming ability, or swimming behaviour, concluding that the average metacercarial intensity present on the gobies is therefore below the threshold of an altered host response. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Du Toit, Hendrik Daniël
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Gobiidae -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52458 , vital:43666
- Description: Coryogalops sordidus(Epaulette goby), is a cryptobenthic species of the Family Gobiidae that iscommonly foundoccupying turbulent surf zones, calm rock pools, and sand and mud flats, where they are generally carnivorous predators. The distribution of C. sordidushas been recorded for Kenya, Tanzania, Mozambique, and South Africa. The species is also resident in the microbialite pools on the temperate south east coast of South Africa. Recent reports indicated these gobies to be covered in numerous dark lesions, possibly suggesting that the microbialite pools are a sub-optimal habitat. Preliminary analyses have indicated that the dark lesions are a result of encysted metacercaria of a digenetic trematode (fluke). There werehowever,no current recorded parasiticspecies occurring within microbialite pool nor any records of any parasitic species utilizingC. sordidus as a host in South Africa. Therefore, the aim of this study was to investigate parasite-host interactions and parasite presence in and around themicrobialite pool systems of Algoa Bay using C. sordidusas a study species. Coryogalops sordiduswas identified to be parasitised by digenetic trematode metacercaria of the Family Diplostomidae Poirier, 1886, localised primarily to the host musculature, fins, eyes, and integument with no settlement on any of the visceral organs. Furthermore, C. sordidus was found additionally parasitised by a green leech (Class: Hirundinea) of the Family Piscicolidae Johnston, 1865, localised exclusively to the ventral body surface, underneath the pelvic fin of the host. Further investigation into the life cycle of the trematode, suggested that the most probable final hosts wereherons,namely Ardea cinereaand Egretta garzetta garzetta, and intermediate host likely being the freshwater gastropod Assimineacf.capensis, present inthe upper microbialite pools. In both the microbialite and neighbouring rock pools trematode prevalence was found to oscillate in response to seasonal chemical and climatic conditions, whereas the secondary piscicolid leech parasite was influencedmoreby host presence than environmental conditions. Greater prevalence and intensity were measured in the microbialite pools suggesting that these systems likely contained a suit of favourable conditions that allowed for greater trematode loads to be maintained as compared to neighbouring rock pools. As parasites often have deleterious effects on their hosts, the response can manifest as an altered host behaviour or an increased energetic debt due to elevated immune response activity and the associated cost of tissue repair at sites of parasite aggregation.This study further investigatedifgobies (C. sordidus) infected with metacercarial cysts display higher metabolic ratesordifferent swimming behaviour compared to non-infected individuals. The results indicated that the metacercarial load carried by infected hosts had on average no significant impact on energetics, swimming ability, or swimming behaviour, concluding that the average metacercarial intensity present on the gobies is therefore below the threshold of an altered host response. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text:
- Date Issued: 2021-04
Linking agrochemical pollution with the aquatic ecological integrity of the Twee River Catchment, Western Cape
- Authors: Brink, Zanné
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Ecological integrity
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52326 , vital:43588
- Description: This study was initiated in the Twee River system due to the threat posed by agrochemicals on the occurrence of the endemic and endangered fish species found within the catchment. Poor knowledge and understanding of the environmental effects of fertilizers, pesticides and other agrochemicals among small and large commercial farmers within the study area, in combination with their intensive use may have resulted in chemical contamination above environmentally safe concentrations. Numerous studies have highlighted the fact that more research needs to be conducted to identify the key threats to the continued existence of specifically the Critically Endangered Sedercypris erubescens. The overall aim of this study was to determine the spatial and temporal patterns in aquatic ecosystem diversity in the Twee River catchment as indicated by macroinvertebrate and native fish distribution and abundance. It was further investigated if there was a link between agrochemical pollution and the aquatic ecological integrity of the Twee River catchment. Selected sampling sites were identified and sampled to determine the presence and concentration of pesticides entering the water of the Twee River system during run-off and event-based spraying. Furthermore, the effect of these pesticides on the distribution and abundance of the aquatic biota were determined using SASS5 for the macroinvertebrate populations and visually sampling the distribution of the native and non-native fish in the Twee River catchment. This study supports suggestions made by previous studies, that sub-lethal to lethal concentrations of insecticides could be a threat to the long-term survival of benthic macroinvertebrates and potentially the more sensitive endemic fish species within the Twee River system. More focussed research is needed to address impacts of pesticides within this catchment. Agricultural and conservation efforts should be aimed at developing of a shared vision amongst stakeholders, to allow for the longterm conservation of the endemic fish of the Twee River. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Brink, Zanné
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Ecological integrity
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52326 , vital:43588
- Description: This study was initiated in the Twee River system due to the threat posed by agrochemicals on the occurrence of the endemic and endangered fish species found within the catchment. Poor knowledge and understanding of the environmental effects of fertilizers, pesticides and other agrochemicals among small and large commercial farmers within the study area, in combination with their intensive use may have resulted in chemical contamination above environmentally safe concentrations. Numerous studies have highlighted the fact that more research needs to be conducted to identify the key threats to the continued existence of specifically the Critically Endangered Sedercypris erubescens. The overall aim of this study was to determine the spatial and temporal patterns in aquatic ecosystem diversity in the Twee River catchment as indicated by macroinvertebrate and native fish distribution and abundance. It was further investigated if there was a link between agrochemical pollution and the aquatic ecological integrity of the Twee River catchment. Selected sampling sites were identified and sampled to determine the presence and concentration of pesticides entering the water of the Twee River system during run-off and event-based spraying. Furthermore, the effect of these pesticides on the distribution and abundance of the aquatic biota were determined using SASS5 for the macroinvertebrate populations and visually sampling the distribution of the native and non-native fish in the Twee River catchment. This study supports suggestions made by previous studies, that sub-lethal to lethal concentrations of insecticides could be a threat to the long-term survival of benthic macroinvertebrates and potentially the more sensitive endemic fish species within the Twee River system. More focussed research is needed to address impacts of pesticides within this catchment. Agricultural and conservation efforts should be aimed at developing of a shared vision amongst stakeholders, to allow for the longterm conservation of the endemic fish of the Twee River. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
Nurse educators’ understanding of Africanising undergraduate education at a nursing education institution
- Authors: Mlatsha, Ayanda
- Date: 2021-04
- Subjects: Nursing --South Africa , Organizational Change -- Education , Educational change--South Africa --Nursing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/60764 , vital:67197
- Description: In the light of transformation and the need for a relatively recently liberated country to enhance higher education, one of the foremost demands of South Africans in education was that of Africanising higher education. Africanising is associated with the term ‘transformation’. The latter is a process that requires the revision of the existing education system towards that of an African-contextualised education system in Africa. Concurrently the nursing profession has an increased need for transcultural nursing in education to ensure that undergraduates deliver culturally aligned and African contextualised nursing care. At present, there is no clear description of how Africanising nursing education can be carried out by nurse educators. Hence some educators argue that the change may not be a smooth process as there is no blueprint that provides guidance for how the process should be conducted. This study intended to assist in describing the meaning of Africanising nursing education as it is understood by nurse educators in a Nursing Education Institution (NEI). Therefore, this study explored and described nurse educators’ understanding of Africanising undergraduate nursing education at a NEI in the Nelson Mandela Bay in the Eastern Cape, South Africa in order to construct recommendations for NEI managers and nurse educators on how the process of Africanising undergraduate nursing education at NEIs can be facilitated. The researcher used a qualitative descriptive approach. The postcolonial theory was used to underpin this study. Purposive sampling was utilised to select nurse educators for participation in the study. Each of the twelve participants were asked to draw a naïve sketch regarding their understanding of fricanisation of the undergraduate nursing education followed by an individual semi-structured interview. Data collection was conducted online, using recorded Zoom sessions. Content analysis was used to aanalyse the data and the findings were used to construct recommendations for NEI managers and nurse educators on how the process of Africanising undergraduate nursing education at NEIs can be enhanced. Throughout the study ethical principles as well as the requirements related to the concepts of trustworthiness, credibility; dependability; confirmability and transferability were upheld. , Thesis (MSc) -- Faculty of Health Sciences, School of Clinical care and Medicinal Sciences, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Mlatsha, Ayanda
- Date: 2021-04
- Subjects: Nursing --South Africa , Organizational Change -- Education , Educational change--South Africa --Nursing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/60764 , vital:67197
- Description: In the light of transformation and the need for a relatively recently liberated country to enhance higher education, one of the foremost demands of South Africans in education was that of Africanising higher education. Africanising is associated with the term ‘transformation’. The latter is a process that requires the revision of the existing education system towards that of an African-contextualised education system in Africa. Concurrently the nursing profession has an increased need for transcultural nursing in education to ensure that undergraduates deliver culturally aligned and African contextualised nursing care. At present, there is no clear description of how Africanising nursing education can be carried out by nurse educators. Hence some educators argue that the change may not be a smooth process as there is no blueprint that provides guidance for how the process should be conducted. This study intended to assist in describing the meaning of Africanising nursing education as it is understood by nurse educators in a Nursing Education Institution (NEI). Therefore, this study explored and described nurse educators’ understanding of Africanising undergraduate nursing education at a NEI in the Nelson Mandela Bay in the Eastern Cape, South Africa in order to construct recommendations for NEI managers and nurse educators on how the process of Africanising undergraduate nursing education at NEIs can be facilitated. The researcher used a qualitative descriptive approach. The postcolonial theory was used to underpin this study. Purposive sampling was utilised to select nurse educators for participation in the study. Each of the twelve participants were asked to draw a naïve sketch regarding their understanding of fricanisation of the undergraduate nursing education followed by an individual semi-structured interview. Data collection was conducted online, using recorded Zoom sessions. Content analysis was used to aanalyse the data and the findings were used to construct recommendations for NEI managers and nurse educators on how the process of Africanising undergraduate nursing education at NEIs can be enhanced. Throughout the study ethical principles as well as the requirements related to the concepts of trustworthiness, credibility; dependability; confirmability and transferability were upheld. , Thesis (MSc) -- Faculty of Health Sciences, School of Clinical care and Medicinal Sciences, 2021
- Full Text:
- Date Issued: 2021-04
On the ideals and semimodules of commutative semirings
- Authors: Olivier, Ruan
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52782 , vital:44026
- Description: Semirings are a generalisation of rings where additive inverses need not exist. In this dissertation, we focus on results of commutative semirings with non-zero identity. Many results that we study are analogous to results from commutative rings with non-zero identity. Properties which are unique to semirings are also investigated, such as semirings where all elements are additively idempotent. The notion of ideals is examined in the context of a semiring. Specifically, prime ideals, maximal ideals, k-ideals and partitioning ideals of semirings are considered. Additionally, the module over a ring is generalised to a semimodule over a semiring. The emphasis is on prime subsemimodules and multiplication semimodules. Lastly, invertible ideals of semirings are examined. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Olivier, Ruan
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52782 , vital:44026
- Description: Semirings are a generalisation of rings where additive inverses need not exist. In this dissertation, we focus on results of commutative semirings with non-zero identity. Many results that we study are analogous to results from commutative rings with non-zero identity. Properties which are unique to semirings are also investigated, such as semirings where all elements are additively idempotent. The notion of ideals is examined in the context of a semiring. Specifically, prime ideals, maximal ideals, k-ideals and partitioning ideals of semirings are considered. Additionally, the module over a ring is generalised to a semimodule over a semiring. The emphasis is on prime subsemimodules and multiplication semimodules. Lastly, invertible ideals of semirings are examined. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2021
- Full Text:
- Date Issued: 2021-04
Optimising the uptake of [𝐈𝐫𝐂𝐥𝟔]𝟐− by a diammonium resin: HCl effect and resin performance
- Authors: Ngayeka, Mbokazi Zizipho
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54089 , vital:46284
- Description: The separation of [IrCl6]2- from [RhCl5(H2O)]2- by silica microparticles functionalized with 1,10-diamindecane (C10) and quaternized with 4-nitrobenzylchloride (NO2Benz) in various hydrochloric acid mediums was investigated by continuous column studies. The sorbent materials were synthesized using three different routes: Synthesis route 1 (NaI catalyzed synthesis of diammonium functionalized silica microparticles), Synthesis Route 2 (via silylazation of silica followed by functionalization) and Synthesis Route 3 (silane-based sorbent material). The functionalized sorbent materials were characterized by NMR, Microanalysis, SEM-EDS, FT-IR, TGA and BET surface area. The separation efficiency of the quaternary diammonium cations was investigated under dynamic flow adsorption conditions. Preliminary ICP-OES runs were done, at 6 M HCl, to assess which synthesis route gave the best performing sorbent material. [IrCl6]2- selectivity of the sorbent materials was achieved by washing with an HCl solution to remove unadsorbed metal species, then stripping off the [RhCl5(H2O)]2- with 0.05 M of sodium chlorate and the iridium species was eluted with a 20% HCl solution. From the preliminary ICP-OES, loading capacities were calculated, and it was observed that the three sorbent materials from synthesis route 2 (13.89 mg/g for (4) SSC10NO2Benz-A, 1.44 mg/g for (5) SSC10NO2Benz-HoA, and 1.0859 mg/g for (6) SSC10NO2Benz-DoA) showed the highest uptake of [IrCl6]2- and route 1 (1.89 mg/g for (1) SSC10NO2Benz-A, 1.25 mg/g for (2) SSC10NO2Benz-HoA and 0.99 mg/g for (3) SSC10NO2Benz-DoA ) and Route 3 (0.55 mg/g for (7) SC10-AI and 0.755 mg/g for (8) SC10-ACl) materials did not perform efficiently enough, thus were not used further for the HCl study. Within synthesis route 2, three sorbent materials were evaluated, which had varying quantities of the cation: SSC10NO2Benz-A (having a quantity previously used in our research and denoted A), SSC10NO2Benz-HoA (having a quantity Half of A) and SSC10NO2Benz-DoA (having a quantity double of A). SSC10NO2Benz-A showed the highest loading capacity than SSC10NO2Benz-HoA and SSC10NO2Benz-DoA; HCl studies were carried out using SSC10NO2Benz-A. HCl solution having different concentrations (5, 5.5 , 6 , 6.6 and 6.8 M) were used to prepare the metal solutions. This was done to assess which HCl concentration gave the best metal solution containing high amounts of [IrCl6]2- and [RhCl5(H2O)]2-, which would result in a more efficient separation. An auto titrator was used to standardize the HCl concentrations, and the metal ion chloride species solutions were determined by UV-Vis, and their concentrations were confirmed with ICP-OES. Column sorption of iridium and rhodium on SSC10NO2Benz-A using these HCl solutions was carried out, and loading capacities of [IrCl6]2- were obtained. The loading capacities of the 5 M, 5.5 M, 6 M, 6,6 M and 6.8 M HCl solutions for [IrCl6]2- were 2.64, 4.01, 13.89, 18.15 and 7.23 mg/g, respectively. The optimum separation conditions were thus determined by investigating effective parameters such as the method of synthesis, silica to cation ratio, HCl concentration and flow rate. This thesis presents quaternary diammonium sorbent materials that could be applied in feed solutions from ore processing for iridium recovery. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Ngayeka, Mbokazi Zizipho
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/54089 , vital:46284
- Description: The separation of [IrCl6]2- from [RhCl5(H2O)]2- by silica microparticles functionalized with 1,10-diamindecane (C10) and quaternized with 4-nitrobenzylchloride (NO2Benz) in various hydrochloric acid mediums was investigated by continuous column studies. The sorbent materials were synthesized using three different routes: Synthesis route 1 (NaI catalyzed synthesis of diammonium functionalized silica microparticles), Synthesis Route 2 (via silylazation of silica followed by functionalization) and Synthesis Route 3 (silane-based sorbent material). The functionalized sorbent materials were characterized by NMR, Microanalysis, SEM-EDS, FT-IR, TGA and BET surface area. The separation efficiency of the quaternary diammonium cations was investigated under dynamic flow adsorption conditions. Preliminary ICP-OES runs were done, at 6 M HCl, to assess which synthesis route gave the best performing sorbent material. [IrCl6]2- selectivity of the sorbent materials was achieved by washing with an HCl solution to remove unadsorbed metal species, then stripping off the [RhCl5(H2O)]2- with 0.05 M of sodium chlorate and the iridium species was eluted with a 20% HCl solution. From the preliminary ICP-OES, loading capacities were calculated, and it was observed that the three sorbent materials from synthesis route 2 (13.89 mg/g for (4) SSC10NO2Benz-A, 1.44 mg/g for (5) SSC10NO2Benz-HoA, and 1.0859 mg/g for (6) SSC10NO2Benz-DoA) showed the highest uptake of [IrCl6]2- and route 1 (1.89 mg/g for (1) SSC10NO2Benz-A, 1.25 mg/g for (2) SSC10NO2Benz-HoA and 0.99 mg/g for (3) SSC10NO2Benz-DoA ) and Route 3 (0.55 mg/g for (7) SC10-AI and 0.755 mg/g for (8) SC10-ACl) materials did not perform efficiently enough, thus were not used further for the HCl study. Within synthesis route 2, three sorbent materials were evaluated, which had varying quantities of the cation: SSC10NO2Benz-A (having a quantity previously used in our research and denoted A), SSC10NO2Benz-HoA (having a quantity Half of A) and SSC10NO2Benz-DoA (having a quantity double of A). SSC10NO2Benz-A showed the highest loading capacity than SSC10NO2Benz-HoA and SSC10NO2Benz-DoA; HCl studies were carried out using SSC10NO2Benz-A. HCl solution having different concentrations (5, 5.5 , 6 , 6.6 and 6.8 M) were used to prepare the metal solutions. This was done to assess which HCl concentration gave the best metal solution containing high amounts of [IrCl6]2- and [RhCl5(H2O)]2-, which would result in a more efficient separation. An auto titrator was used to standardize the HCl concentrations, and the metal ion chloride species solutions were determined by UV-Vis, and their concentrations were confirmed with ICP-OES. Column sorption of iridium and rhodium on SSC10NO2Benz-A using these HCl solutions was carried out, and loading capacities of [IrCl6]2- were obtained. The loading capacities of the 5 M, 5.5 M, 6 M, 6,6 M and 6.8 M HCl solutions for [IrCl6]2- were 2.64, 4.01, 13.89, 18.15 and 7.23 mg/g, respectively. The optimum separation conditions were thus determined by investigating effective parameters such as the method of synthesis, silica to cation ratio, HCl concentration and flow rate. This thesis presents quaternary diammonium sorbent materials that could be applied in feed solutions from ore processing for iridium recovery. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text:
- Date Issued: 2021-04
Participatory mapping of cultural ecosystem services in the Mountain Zebra National Park, South Africa
- Authors: Mpapane, Nelsiwe Pertunia
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Nature--Effect of human beings on--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52103 , vital:43432
- Description: Cultural ecosystem services (CES) are an essential part of human well-being. CES characterize the intangible connections that people have with their surrounding environments, and act as vessels to facilitate the understanding of meaningful and respectful relationships between humans and nature, which are necessary for sustainability. However, CES render themselves as complex cultural dimensions that are difficult to connect to specific aspects of an ecosystem, or to measure and manage. Thus, a progressive approach is required for promoting effective management of CES within landscapes. This thesis endeavours to understand human─nature interactions in protected areas, the CES benefits that arise from such interactions, and the links of these to ecosystems, facilities or features within the landscape. Protected areas represent some of the last remaining intact ecological areas that support biodiversity conservation and human─nature experiences. Protected areas, such as the Mountain Zebra National Park, are therefore suitable study sites to cast light on: (a) how human─nature relationships manifest in parks, (b) which CES are experienced by visitors, (c) which landscape features are associated with CES benefits, (d) who visits the Park, and (e) how the delivery and/or accessibility of CES to visitors of the Park could be improved. My research involved qualitative and spatial elements as forms of enquiry over a period of six months of data collection. I used semi-structured interviews (n = 20) paired with a participatory mapping approach. Additionally, I performed a comparative analysis using a peer-reviewed paper that focused on the management perspectives of CES delivery, to seek out similarities and differences between management perspectives and actual visitor experiences. The findings of this study have outlined that the Mountain Zebra National Park offers significant benefits to visitors. Aesthetic, recreational, inspirational value and cultural heritage emerged as the most frequently mapped CES. The findings have also shown that CES benefits are widely distributed across the landscape, with a spatial correlation in hotspot areas. Moreover, amenities or built infrastructure such as picnic iii sites, camping areas and viewpoints within the Park, are crucial for strengthening social relationships among family and friends, as well as in aiding the delivery of CES. This study provides insights into the subjective and diverse ways that human─nature relationships translate into CES benefits. It also sheds light on the importance of adequate planning within protected areas, for the maximization of the benefits from CES to people without compromising the mandate of biodiversity conservation. This study also contributes to a growing body of evidence that documents human─nature interactions in, and non-material benefits acquired from, protected areas within South Africa. I further advocate for improved access, adequate infrastructure, awareness creation and strategies to attract the younger generation to the national parks of South Africa. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Mpapane, Nelsiwe Pertunia
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Nature--Effect of human beings on--South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52103 , vital:43432
- Description: Cultural ecosystem services (CES) are an essential part of human well-being. CES characterize the intangible connections that people have with their surrounding environments, and act as vessels to facilitate the understanding of meaningful and respectful relationships between humans and nature, which are necessary for sustainability. However, CES render themselves as complex cultural dimensions that are difficult to connect to specific aspects of an ecosystem, or to measure and manage. Thus, a progressive approach is required for promoting effective management of CES within landscapes. This thesis endeavours to understand human─nature interactions in protected areas, the CES benefits that arise from such interactions, and the links of these to ecosystems, facilities or features within the landscape. Protected areas represent some of the last remaining intact ecological areas that support biodiversity conservation and human─nature experiences. Protected areas, such as the Mountain Zebra National Park, are therefore suitable study sites to cast light on: (a) how human─nature relationships manifest in parks, (b) which CES are experienced by visitors, (c) which landscape features are associated with CES benefits, (d) who visits the Park, and (e) how the delivery and/or accessibility of CES to visitors of the Park could be improved. My research involved qualitative and spatial elements as forms of enquiry over a period of six months of data collection. I used semi-structured interviews (n = 20) paired with a participatory mapping approach. Additionally, I performed a comparative analysis using a peer-reviewed paper that focused on the management perspectives of CES delivery, to seek out similarities and differences between management perspectives and actual visitor experiences. The findings of this study have outlined that the Mountain Zebra National Park offers significant benefits to visitors. Aesthetic, recreational, inspirational value and cultural heritage emerged as the most frequently mapped CES. The findings have also shown that CES benefits are widely distributed across the landscape, with a spatial correlation in hotspot areas. Moreover, amenities or built infrastructure such as picnic iii sites, camping areas and viewpoints within the Park, are crucial for strengthening social relationships among family and friends, as well as in aiding the delivery of CES. This study provides insights into the subjective and diverse ways that human─nature relationships translate into CES benefits. It also sheds light on the importance of adequate planning within protected areas, for the maximization of the benefits from CES to people without compromising the mandate of biodiversity conservation. This study also contributes to a growing body of evidence that documents human─nature interactions in, and non-material benefits acquired from, protected areas within South Africa. I further advocate for improved access, adequate infrastructure, awareness creation and strategies to attract the younger generation to the national parks of South Africa. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
Recreating a wetland at an abandoned saltworks : towards a rehabilitation plan
- Authors: Wasserman, Johan
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52146 , vital:43450
- Description: A saltworks at Swartkops Estuary was abandoned in 2018. While operational, the saltworks hosted some of the largest breeding colonies of several shorebird species in southern Africa and hosted thousands of Palearctic migrant waterbirds annually. The abandonment of the saltworks has resulted in the loss of the artificially managed hydrological regime and therefore the wetland function and habitat value of the site, and the rich and diverse avifauna that once occurred at the site have not returned. The rehabilitation of the saltworks as a wetland that functions as a waterbird sanctuary is currently being organised, and this research aimed to create a plan for implementing and monitoring the rehabilitation. In order to do so, the baseline environmental condition of the abandoned saltworks was established, the possible rehabilitation interventions necessary for rehabilitating the site were assessed, and the potential ecological implications of any interventions were investigated. The assessment of the saltworks’ baseline condition revealed that the site is now characterised by vast expanses of dry hypersaline sediment with sparse patches of monospecific vegetation and depauperate avifauna. The once rich and diverse waterbird communities have all but disappeared since the site was abandoned and are unlikely to return unless a managed hydrological regime is reinstated. Furthermore, it is improbable that salt marsh vegetation will cover the abandoned saltworks primarily due to the high sediment salinity that will persist unless the saltpans are flooded. The area will likely remain barren with little ecological value if no rehabilitation action is taken. Two potential rehabilitation options for reinstating a hydrological regime at the saltworks were identified: (1) pumping estuary water into all of the saltpans; or (2) pumping estuary water into some of the saltpans, while allowing the largest one to be filled with stormwater. Both options were deemed to be feasible; however, the second option will likely have lower running costs. The use of stormwater to fill the one saltpan is expected to result in brackish conditions initially, while the saltpans filled with estuary water would have salinity levels ranging from euhaline to slightly hypersaline. Both the stormwater and estuary water are rich in inorganic nutrients – the estuary water is rich in both dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), while the stormwater has an exceptionally high DIN content. This raised concerns of creating eutrophic wetlands with detrimental conditions such as algal blooms and a hypoxic water column. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Wasserman, Johan
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52146 , vital:43450
- Description: A saltworks at Swartkops Estuary was abandoned in 2018. While operational, the saltworks hosted some of the largest breeding colonies of several shorebird species in southern Africa and hosted thousands of Palearctic migrant waterbirds annually. The abandonment of the saltworks has resulted in the loss of the artificially managed hydrological regime and therefore the wetland function and habitat value of the site, and the rich and diverse avifauna that once occurred at the site have not returned. The rehabilitation of the saltworks as a wetland that functions as a waterbird sanctuary is currently being organised, and this research aimed to create a plan for implementing and monitoring the rehabilitation. In order to do so, the baseline environmental condition of the abandoned saltworks was established, the possible rehabilitation interventions necessary for rehabilitating the site were assessed, and the potential ecological implications of any interventions were investigated. The assessment of the saltworks’ baseline condition revealed that the site is now characterised by vast expanses of dry hypersaline sediment with sparse patches of monospecific vegetation and depauperate avifauna. The once rich and diverse waterbird communities have all but disappeared since the site was abandoned and are unlikely to return unless a managed hydrological regime is reinstated. Furthermore, it is improbable that salt marsh vegetation will cover the abandoned saltworks primarily due to the high sediment salinity that will persist unless the saltpans are flooded. The area will likely remain barren with little ecological value if no rehabilitation action is taken. Two potential rehabilitation options for reinstating a hydrological regime at the saltworks were identified: (1) pumping estuary water into all of the saltpans; or (2) pumping estuary water into some of the saltpans, while allowing the largest one to be filled with stormwater. Both options were deemed to be feasible; however, the second option will likely have lower running costs. The use of stormwater to fill the one saltpan is expected to result in brackish conditions initially, while the saltpans filled with estuary water would have salinity levels ranging from euhaline to slightly hypersaline. Both the stormwater and estuary water are rich in inorganic nutrients – the estuary water is rich in both dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), while the stormwater has an exceptionally high DIN content. This raised concerns of creating eutrophic wetlands with detrimental conditions such as algal blooms and a hypoxic water column. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
Rheology behaviour of slurries as a function of particle size and ion concentration
- Authors: Kondlo, Princess Kholiwe
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53333 , vital:45141
- Description: In this work, the rheological properties of alumina slurries milled to different particle sizes were investigated. Viscosity increases as the particle size decreases. When increasing amounts of calcium hydroxide, strontium hydroxide or barium hydroxide are added, the viscosity first goes down and then goes up. This can be explained in terms of changes in pH and changes in ionic strength impacting on the surface potential of the particles in suspension. Adding the same concentration of different cations results in different viscosities, with the order being (from high to low viscosity) Ba>Sr>Ca. Effects of partial dissolution of and structural changes to the alumina particles at high pH cannot be excluded. In order to better understanding the different effects, it was attempted to measure the zeta potential of the slurries at different pH values. This resulted in highly positive zeta potential values over the complete pH range, without the observationof an iso-electric point. This does not fit to the observed changes in rheology and contrasts withliterature data. One explanation would be that the measurement system used is unsuitable to yield correct zeta potential values for the materials under investigation. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Kondlo, Princess Kholiwe
- Date: 2021-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/53333 , vital:45141
- Description: In this work, the rheological properties of alumina slurries milled to different particle sizes were investigated. Viscosity increases as the particle size decreases. When increasing amounts of calcium hydroxide, strontium hydroxide or barium hydroxide are added, the viscosity first goes down and then goes up. This can be explained in terms of changes in pH and changes in ionic strength impacting on the surface potential of the particles in suspension. Adding the same concentration of different cations results in different viscosities, with the order being (from high to low viscosity) Ba>Sr>Ca. Effects of partial dissolution of and structural changes to the alumina particles at high pH cannot be excluded. In order to better understanding the different effects, it was attempted to measure the zeta potential of the slurries at different pH values. This resulted in highly positive zeta potential values over the complete pH range, without the observationof an iso-electric point. This does not fit to the observed changes in rheology and contrasts withliterature data. One explanation would be that the measurement system used is unsuitable to yield correct zeta potential values for the materials under investigation. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
- Full Text:
- Date Issued: 2021-04
Synthesis of coumarin based fluorescent chemosensors for the detection of metal ions.
- Authors: Hamukoshi, Simeon Shiweda
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Organic compounds--Synthesis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52041 , vital:43422
- Description: The study focused on the synthesis of three coumarin-based chemosensors; hydrazone fluorescent chemosensor , azo-benzothiazole dye and azo-quinoline dye. The hydrazone fluorescent chemosensor was synthesised through multiple reaction steps were the azide functionality at position 8 of the coumarin backbone was replaced with the hydrazone group in the last reaction step. The azo dyes were synthesised through a two step reaction process. The photophysical properties of all three chemosensors were investigated. The hydrazone chemosensor and azo-benzothiazole dye presented high absorption and emission, while the azo-quinoline only presented absorption properties. The chemosensing ability of the three products were investigated through absorption and emission. The hydrazone chemosensor was found to be highly selective towards Fe3+ in water and the dyes were found to be selective towards Hg2+. The mechanisms of interaction between the chemosensors and their selective metal ions were investigated via computational analysis and 1H NMR analysis. All of the chemosensors where characyerised using 1H NMR, Fourier Transform Infrared Spectrometer (FTIR) and the X Ray Chrystal structure for the hydrazone chemosensor was obtained via X ray Chrystallography. Finally, the electron density distribution of the all synthesised compounds their predicted stable metal ion complexes was determined using Density Functionaly Theory (DFT). , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Hamukoshi, Simeon Shiweda
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Organic compounds--Synthesis
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52041 , vital:43422
- Description: The study focused on the synthesis of three coumarin-based chemosensors; hydrazone fluorescent chemosensor , azo-benzothiazole dye and azo-quinoline dye. The hydrazone fluorescent chemosensor was synthesised through multiple reaction steps were the azide functionality at position 8 of the coumarin backbone was replaced with the hydrazone group in the last reaction step. The azo dyes were synthesised through a two step reaction process. The photophysical properties of all three chemosensors were investigated. The hydrazone chemosensor and azo-benzothiazole dye presented high absorption and emission, while the azo-quinoline only presented absorption properties. The chemosensing ability of the three products were investigated through absorption and emission. The hydrazone chemosensor was found to be highly selective towards Fe3+ in water and the dyes were found to be selective towards Hg2+. The mechanisms of interaction between the chemosensors and their selective metal ions were investigated via computational analysis and 1H NMR analysis. All of the chemosensors where characyerised using 1H NMR, Fourier Transform Infrared Spectrometer (FTIR) and the X Ray Chrystal structure for the hydrazone chemosensor was obtained via X ray Chrystallography. Finally, the electron density distribution of the all synthesised compounds their predicted stable metal ion complexes was determined using Density Functionaly Theory (DFT). , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
Testing alternative Pinus species and hybrids for the South African structural pole market
- Authors: Ndovela, Lisakhanya Sizo
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52002 , vital:43435
- Description: According to the South African National Standards, only Pinus canariensis, Pinus pinaster and Pinus radiata are suitable to be used as structural softwood poles. Of the three Pinus species mentioned, only P. radiata is still planted in South Africa and its future and availability is uncertain. The lack of availability of structural pine poles necessitates the South African forestry industry to look at alternative softwood species to plant. The broad aim of this study was to determine whether there are alternative Pinus species or hybrids that can be planted in South Africa’s Western and Southern Cape areas that will have suitable properties to be used as a resource for structural poles. This document reports on the testing of the strength and stiffness, as well as other relevant properties, of poles from several Pinus species and Pinus hybrids. The poles were derived from thinned eight-year-old tree stands in Knysna, Western Cape. Poles were peeled, kiln dried and graded before bending tests were carried out. Species and hybrids were also assessed for differences within a tree along the length. Also, the correlation between modulus of rupture (MOR), modulus of elasticity (MOE) and wood grading properties was evaluated. The results showed that there was a highly significant effect of species and log position on the mean MOR of the poles. In general, poles from the bottom of the tree had a higher mean MOR than poles from the top of the tree. There was also a highly significant effect of species and pole position on the mean MOE of poles, with poles at the top of the trees generally having higher MOE values. A very concerning finding was that the 5th percentile MOR and mean MOE values of all the species were far lower than required by SANS 10163-1 (2003). Even for the best performing species, P. radiata, the MOR 5th percentile value was less than half the required value, while the mean MOE was also 39% lower than the required mean MOE. Apart from P. radiata, the P. maximinoi performed the best of all species and hybrids since it had a statistically similar mean MOR and MOE to P. radiata. P. elliottii and the hybrid P. elliottii x caribaea had statistically significant lower MOR and MOE than P. radiata. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Ndovela, Lisakhanya Sizo
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52002 , vital:43435
- Description: According to the South African National Standards, only Pinus canariensis, Pinus pinaster and Pinus radiata are suitable to be used as structural softwood poles. Of the three Pinus species mentioned, only P. radiata is still planted in South Africa and its future and availability is uncertain. The lack of availability of structural pine poles necessitates the South African forestry industry to look at alternative softwood species to plant. The broad aim of this study was to determine whether there are alternative Pinus species or hybrids that can be planted in South Africa’s Western and Southern Cape areas that will have suitable properties to be used as a resource for structural poles. This document reports on the testing of the strength and stiffness, as well as other relevant properties, of poles from several Pinus species and Pinus hybrids. The poles were derived from thinned eight-year-old tree stands in Knysna, Western Cape. Poles were peeled, kiln dried and graded before bending tests were carried out. Species and hybrids were also assessed for differences within a tree along the length. Also, the correlation between modulus of rupture (MOR), modulus of elasticity (MOE) and wood grading properties was evaluated. The results showed that there was a highly significant effect of species and log position on the mean MOR of the poles. In general, poles from the bottom of the tree had a higher mean MOR than poles from the top of the tree. There was also a highly significant effect of species and pole position on the mean MOE of poles, with poles at the top of the trees generally having higher MOE values. A very concerning finding was that the 5th percentile MOR and mean MOE values of all the species were far lower than required by SANS 10163-1 (2003). Even for the best performing species, P. radiata, the MOR 5th percentile value was less than half the required value, while the mean MOE was also 39% lower than the required mean MOE. Apart from P. radiata, the P. maximinoi performed the best of all species and hybrids since it had a statistically similar mean MOR and MOE to P. radiata. P. elliottii and the hybrid P. elliottii x caribaea had statistically significant lower MOR and MOE than P. radiata. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
The effect of laundering on the physical and thermal properties of phase change textile materials
- Authors: Scheepers, Ricardo
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Textile chemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52038 , vital:43443
- Description: Phase change materials (PCMs) have been incorporated into clothing and textiles to provide added value in terms of thermoregulation and thus added comfort to the wearer in extreme weather conditions and sporting activities. Since clothing is laundered many times during the service life of the textile, the effects of simulated domestic laundering on the physical and thermal properties of a non-woven textile which contains PCMs were investigated. The thermal properties, such as the thermal degradation, melting, evaporation and crystallisation were measured by the TGA and DSC analytical techniques. The physical properties, such as the microcapsule size distribution, and the microcapsule morphologies of the PCM microcapsules, were measured by the SEM and Raman analytical techniques. The main objectives of this study were to determine the effect of repeated laundering at different wash temperatures on the mass loss, enthalpy, and physical changes in PCM. Thermal degradation as determined by TGA thermograms was found to be higher at a wash temperature of 60°C relative to that of a wash temperature at 30°C, the mass loss being 4.6% more at 60°C than at 30°C. This was asserted to physical changes such as size and shape of the PCM microcapsules as evident in SEM images. The SEM images showed broken and collapsed PCM microcapsules in the web and around the fibre, indicating evaporation of the thermoregulating content of the PCM. It was found that the heat capacity of the sample washed at 60°C was much lower than that of the unwashed sample, the difference being approximately 50% in terms of the latent heat capacity as determined by DSC thermograms. This implies that the latent heat effectiveness of the PCM has decreased significantly. The physical properties of the PCM such as the intermolecular interaction, the intensity and width of peaks, polarisation, degree of crystallinity and the orientation changed as illustrated in the Raman analysis. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Scheepers, Ricardo
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Textile chemistry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52038 , vital:43443
- Description: Phase change materials (PCMs) have been incorporated into clothing and textiles to provide added value in terms of thermoregulation and thus added comfort to the wearer in extreme weather conditions and sporting activities. Since clothing is laundered many times during the service life of the textile, the effects of simulated domestic laundering on the physical and thermal properties of a non-woven textile which contains PCMs were investigated. The thermal properties, such as the thermal degradation, melting, evaporation and crystallisation were measured by the TGA and DSC analytical techniques. The physical properties, such as the microcapsule size distribution, and the microcapsule morphologies of the PCM microcapsules, were measured by the SEM and Raman analytical techniques. The main objectives of this study were to determine the effect of repeated laundering at different wash temperatures on the mass loss, enthalpy, and physical changes in PCM. Thermal degradation as determined by TGA thermograms was found to be higher at a wash temperature of 60°C relative to that of a wash temperature at 30°C, the mass loss being 4.6% more at 60°C than at 30°C. This was asserted to physical changes such as size and shape of the PCM microcapsules as evident in SEM images. The SEM images showed broken and collapsed PCM microcapsules in the web and around the fibre, indicating evaporation of the thermoregulating content of the PCM. It was found that the heat capacity of the sample washed at 60°C was much lower than that of the unwashed sample, the difference being approximately 50% in terms of the latent heat capacity as determined by DSC thermograms. This implies that the latent heat effectiveness of the PCM has decreased significantly. The physical properties of the PCM such as the intermolecular interaction, the intensity and width of peaks, polarisation, degree of crystallinity and the orientation changed as illustrated in the Raman analysis. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
The feeding ecology and habitat selection of small antelopes in the Overberg Renosterveld, Western Cape
- Authors: Jansen van Vuuren, Amauréé
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Fynbos ecology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52014 , vital:43436
- Description: Human impacts have altered natural ecosystems which required species to become resilient in order to survive the anthropogenic landscape. The study area is located in the highly fragmented Overberg area in the Western Cape of South Africa. The high degree of fragmentation of the area is as a result of the nutrient rich soils and favourable topography which makes the area highly suitable for agricultural practices. The agriculture practiced in the area is mainly grain crops and livestock farming and the remaining patches of natural vegetation consist of Fynbos and Renosterveld vegetation. The patches of Fynbos and Renosterveld vegetation acts as movement corridors to allow species movement through the anthropogenic landscape. The anthropogenic landscape requires species to be resilient and to adapt to a novel habitat which poses new threats as well as new resources. The aim of the study is to investigate the effect of landscape transformation, resulting from agricultural practices, on the feeding and behavioural dynamics of five small specialist browser species in a fragmented lowland Fynbos and Renosterveld system. The objectives were to determine the forage preferences of each of the five specialist browser species and to determine which site-specific characteristics, drive the seasonal habitat use of the five specialist browser species. The five specialist browser species were bushbuck (Tragelaphus sylvaticus), Cape grysbok (Rhaphicerus melanotis), common duiker (Sylvicapra grimmia), grey rhebok (Pelea capreolus) and steenbok (Rhaphicerus campestris). To determine the dietary selection of the five specialist browser species we collected dung samples and performed a histological analysis on the dung samples. To determine the habitat use of the five specialist browser species we used an occupancy analysis framework on camera trap data collected on each of the species. Some species appeared more dependent on the food resources from the anthropogenic landscape and spent more time in the crops but required close by cover of natural vegetation. Others appeared more dependent on the remaining pockets of natural vegetation for food resources and spent more time in the natural vegetation. These species would occasionally move into the crops to utilise the food resources. Both the anthropogenic as well as the natural landscape contributed to the diets of all of the species. These species have been resilient to changes in the landscape and appear to be benefiting from the resources presented in the novel landscape. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Jansen van Vuuren, Amauréé
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Fynbos ecology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52014 , vital:43436
- Description: Human impacts have altered natural ecosystems which required species to become resilient in order to survive the anthropogenic landscape. The study area is located in the highly fragmented Overberg area in the Western Cape of South Africa. The high degree of fragmentation of the area is as a result of the nutrient rich soils and favourable topography which makes the area highly suitable for agricultural practices. The agriculture practiced in the area is mainly grain crops and livestock farming and the remaining patches of natural vegetation consist of Fynbos and Renosterveld vegetation. The patches of Fynbos and Renosterveld vegetation acts as movement corridors to allow species movement through the anthropogenic landscape. The anthropogenic landscape requires species to be resilient and to adapt to a novel habitat which poses new threats as well as new resources. The aim of the study is to investigate the effect of landscape transformation, resulting from agricultural practices, on the feeding and behavioural dynamics of five small specialist browser species in a fragmented lowland Fynbos and Renosterveld system. The objectives were to determine the forage preferences of each of the five specialist browser species and to determine which site-specific characteristics, drive the seasonal habitat use of the five specialist browser species. The five specialist browser species were bushbuck (Tragelaphus sylvaticus), Cape grysbok (Rhaphicerus melanotis), common duiker (Sylvicapra grimmia), grey rhebok (Pelea capreolus) and steenbok (Rhaphicerus campestris). To determine the dietary selection of the five specialist browser species we collected dung samples and performed a histological analysis on the dung samples. To determine the habitat use of the five specialist browser species we used an occupancy analysis framework on camera trap data collected on each of the species. Some species appeared more dependent on the food resources from the anthropogenic landscape and spent more time in the crops but required close by cover of natural vegetation. Others appeared more dependent on the remaining pockets of natural vegetation for food resources and spent more time in the natural vegetation. These species would occasionally move into the crops to utilise the food resources. Both the anthropogenic as well as the natural landscape contributed to the diets of all of the species. These species have been resilient to changes in the landscape and appear to be benefiting from the resources presented in the novel landscape. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2021
- Full Text: false
- Date Issued: 2021-04
Thiazole derivatives as potential hiv-1 protease inhibitors
- Authors: Hlongwe, Zola
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Enzyme kinetics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52116 , vital:43427
- Description: Series of compounds were screened using Schrodinger suite (Maestro). The DFT calculations were used for geometry optimization of the ligands using the B3YLYP functional and 6-31G basis set, and these structures were used for docking studies. Maestro was used to predict the activity of thiazole derivatives against HIV-1 protease. The range of estimated inhibition constants for these thiazole derivatives (65 nM-5 μM) indicate moderate to weak activity against HIV-1 protease, given that the activity of current protease inhibitors is typically found have experimental inhibition constants around 0.1-2.0 nM. Twenty compounds were selected based on the docking results and they were synthesized and characterized by NMR, FT-IR and elemental analysis. The cytotoxicity studies were done at two different concentrations (100 μM and 10 μM), using the brine shrimp bioassay. All compounds were highly toxic at 100 μM, with the percentage mortality between 20 to 75%. Eight compounds were selected for the enzyme bioassay based on the results obtained from lower concentration (10 μM). In the enzyme inhibition studies, the profile of HIV-1 activity was done at different inhibitor concentrations (800 μM – 10 μM) by measuring the cleavage of the synthetic substrate (Abz-Thr-lle-PNO2Phe=Gln-Arg-NH2) at excitation wavelength of 345/490 nm using fluorescence. Ligands 5 (unsubstituted derivative), 7 (4-nitro derivative) and 16 (4-methoxy derivative) gave percentage inhibition of 39, 45 and 42%, and this activity was very low compared to the activity of the positive control ritonavir (85% enzyme inhibition). Ligands 8 (4-methoxy derivative) and 12 (4-methoxy derivative) gave enzyme inhibition of 70% and 75%. These results suggest that the presence of the methoxy substituents ii increases activity of these compounds against HIV-1 protease. Most of the compounds gave good IC50 values between 12.5-42.7 nM. The bromo-substituted ligand 7 gave the lowest IC50 (12.5 nM). Ligand 11 also gave a good IC50 value of 14.86 nM. The bromo-substituted derivatives showed to be very active compared to other types of thiazole derivatives. Enzyme kinetics were carried out to compare the inhibition constants obtained via computational modelling. Ligand 7 (4-methoxy derivatives) binds better in the active site of HIV-1 protease than other compounds in Class B, with Ki = 50 nM, Km = 23.8 Nm and Vmax = 83.3 nM/min. The unsubstituted (L5), 4-bromo (L7) and 4-nitro (L8) substituted compounds gave inhibition constants of 100 to 112 nM. The in vitro testing yielded higher activity than that determined in silico. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Hlongwe, Zola
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Enzyme kinetics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52116 , vital:43427
- Description: Series of compounds were screened using Schrodinger suite (Maestro). The DFT calculations were used for geometry optimization of the ligands using the B3YLYP functional and 6-31G basis set, and these structures were used for docking studies. Maestro was used to predict the activity of thiazole derivatives against HIV-1 protease. The range of estimated inhibition constants for these thiazole derivatives (65 nM-5 μM) indicate moderate to weak activity against HIV-1 protease, given that the activity of current protease inhibitors is typically found have experimental inhibition constants around 0.1-2.0 nM. Twenty compounds were selected based on the docking results and they were synthesized and characterized by NMR, FT-IR and elemental analysis. The cytotoxicity studies were done at two different concentrations (100 μM and 10 μM), using the brine shrimp bioassay. All compounds were highly toxic at 100 μM, with the percentage mortality between 20 to 75%. Eight compounds were selected for the enzyme bioassay based on the results obtained from lower concentration (10 μM). In the enzyme inhibition studies, the profile of HIV-1 activity was done at different inhibitor concentrations (800 μM – 10 μM) by measuring the cleavage of the synthetic substrate (Abz-Thr-lle-PNO2Phe=Gln-Arg-NH2) at excitation wavelength of 345/490 nm using fluorescence. Ligands 5 (unsubstituted derivative), 7 (4-nitro derivative) and 16 (4-methoxy derivative) gave percentage inhibition of 39, 45 and 42%, and this activity was very low compared to the activity of the positive control ritonavir (85% enzyme inhibition). Ligands 8 (4-methoxy derivative) and 12 (4-methoxy derivative) gave enzyme inhibition of 70% and 75%. These results suggest that the presence of the methoxy substituents ii increases activity of these compounds against HIV-1 protease. Most of the compounds gave good IC50 values between 12.5-42.7 nM. The bromo-substituted ligand 7 gave the lowest IC50 (12.5 nM). Ligand 11 also gave a good IC50 value of 14.86 nM. The bromo-substituted derivatives showed to be very active compared to other types of thiazole derivatives. Enzyme kinetics were carried out to compare the inhibition constants obtained via computational modelling. Ligand 7 (4-methoxy derivatives) binds better in the active site of HIV-1 protease than other compounds in Class B, with Ki = 50 nM, Km = 23.8 Nm and Vmax = 83.3 nM/min. The unsubstituted (L5), 4-bromo (L7) and 4-nitro (L8) substituted compounds gave inhibition constants of 100 to 112 nM. The in vitro testing yielded higher activity than that determined in silico. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
Upwelling over submarine canyons: an in-situ and modelling approach
- Authors: Rautenbach, Gustav
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Oceanography -- Research -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52078 , vital:43442
- Description: The iSimangaliso Wetland Park, located along the coastline of northern KwaZulu-Natal (KZN), hosts South Africa's only tropical coral reef system and is clustered with submarine canyons. These ecosystems support a flourishing diving and pelagic sportfishing industry in the area that contributes tens of millions of rand to the South African Gross Domestic Profit (GDP) annually as well as to provide income and job security for the majority of the local residents. Understanding the oceanographic dynamics, particularly upwelling events, will improve current knowledge of how the ecosystem works and may enhance conservation techniques. The upwelling events within the iSimangaliso Wetland Park results in the influx of cold and nutrient rich waters that supports biological productivity in the area. The complex oceanography, dominated by the Northern Agulhas Current and mesoscale eddies that stem from the Mozambique Channel and South East Madagascar Current (SEMC) is understudied and lacks understanding. This thesis aims to build upon the current knowledge of the upwelling events over the submarine canyons and the concurrent influence on the Mixed Layer Depth (MLD). At the submarine canyons, six anomalous cooling events were identified from surface and subsurface measurements extracted from the Operational Sea Surface Temperature and Ice Analysis (OSTIA) Sea Surface Temperature (SST) and from data collected using Underwater Temperature Recorders (UTRs) over a 12-month period. Depth-integrated lagged correlations showed a 2-to-7-hour lag period from the deep to shallow stations, suggesting that the anomalous cooling events are in fact upwelling events. Wind measurements from the Mbazwana Weather Station and snapshots of sea-level anomalies illustrated that the weaker and shorter upwelling events are driven either by alongshore wind stress or a cyclonic eddy event solely; whereas the stronger event was driven by the combination of both forcing mechanisms. An idealized canyon ocean model is used to interrogate the two forcing mechanisms more fully and showed that the most intense upwelling events are driven by the combined effect of upwelling-favourable alongshore wind stress and a cyclonic eddy which results in strong upward vertical velocity anomalies and the greatest shallowing (6.88 m) of the MLD. With the contribution of the in-situ measurements as a baseline study it is apparent that the idealised model does provide an improved understanding of the upwelling events and forcing mechanism over the submarine canyons within the iSimangaliso Wetland Park. , Thesis (MSc) -- Faculty of Science, Ocean Sciences, 2021
- Full Text: false
- Date Issued: 2021-04
- Authors: Rautenbach, Gustav
- Date: 2021-04
- Subjects: Gqeberha (South Africa) , Eastern Cape (South Africa) , Oceanography -- Research -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/52078 , vital:43442
- Description: The iSimangaliso Wetland Park, located along the coastline of northern KwaZulu-Natal (KZN), hosts South Africa's only tropical coral reef system and is clustered with submarine canyons. These ecosystems support a flourishing diving and pelagic sportfishing industry in the area that contributes tens of millions of rand to the South African Gross Domestic Profit (GDP) annually as well as to provide income and job security for the majority of the local residents. Understanding the oceanographic dynamics, particularly upwelling events, will improve current knowledge of how the ecosystem works and may enhance conservation techniques. The upwelling events within the iSimangaliso Wetland Park results in the influx of cold and nutrient rich waters that supports biological productivity in the area. The complex oceanography, dominated by the Northern Agulhas Current and mesoscale eddies that stem from the Mozambique Channel and South East Madagascar Current (SEMC) is understudied and lacks understanding. This thesis aims to build upon the current knowledge of the upwelling events over the submarine canyons and the concurrent influence on the Mixed Layer Depth (MLD). At the submarine canyons, six anomalous cooling events were identified from surface and subsurface measurements extracted from the Operational Sea Surface Temperature and Ice Analysis (OSTIA) Sea Surface Temperature (SST) and from data collected using Underwater Temperature Recorders (UTRs) over a 12-month period. Depth-integrated lagged correlations showed a 2-to-7-hour lag period from the deep to shallow stations, suggesting that the anomalous cooling events are in fact upwelling events. Wind measurements from the Mbazwana Weather Station and snapshots of sea-level anomalies illustrated that the weaker and shorter upwelling events are driven either by alongshore wind stress or a cyclonic eddy event solely; whereas the stronger event was driven by the combination of both forcing mechanisms. An idealized canyon ocean model is used to interrogate the two forcing mechanisms more fully and showed that the most intense upwelling events are driven by the combined effect of upwelling-favourable alongshore wind stress and a cyclonic eddy which results in strong upward vertical velocity anomalies and the greatest shallowing (6.88 m) of the MLD. With the contribution of the in-situ measurements as a baseline study it is apparent that the idealised model does provide an improved understanding of the upwelling events and forcing mechanism over the submarine canyons within the iSimangaliso Wetland Park. , Thesis (MSc) -- Faculty of Science, Ocean Sciences, 2021
- Full Text: false
- Date Issued: 2021-04