A social-ecological investigation into urban domestic gardens and avifauna in medium-sized towns of the Eastern Cape, South Africa
- Authors: Tricam, Shayla
- Date: 2020
- Subjects: Urban ecology (Biology) -- South Africa , Biotic communites -- South Africa , Gardens -- South Africa -- Managemenet , Birds – Ecology – South Africa , Gardening to attract birds -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145314 , vital:38427
- Description: Urban domestic gardens are an often overlooked component of urban green infrastructure, despite their potential to contribute to the preservation of urban biodiversity. As opposed to public greenspaces, private gardens are individually owned and managed, thus act as social-ecological systems, where the cumulative actions of urban residents can scale up to influence ecological patterns and processes on a larger scale. The diversity of fauna and flora within urban gardens provide a range of ecosystem goods and services, as well as less tangible benefits in the form of recreation, education and culture. However, little is known about the contribution of urban domestic gardens to urban biodiversity and its potential conservation value in South Africa. This study investigated urban domestic gardens along a socio-economic gradient in two medium-sized towns, Grahamstown and Port Alfred in the Eastern Cape, South Africa. This study found distinct differences among urban resident garden management practices as well as the avifauna which were seen within the gardens across the socio-economic gradient. The Garden Management Intensity index was higher within affluent households compared to other socio-economic levels, with subsequent management scores not differing statistically along the gradient. While there was variation within garden management practices, as well as the number of residents who participated in supplementary bird feeding, little variation was seen in the activities which were enjoyed by the residents, indicating numerous benefits the garden environment provides for all urban residents. The bird community composition along the socio-economic gradient displayed patterns directly reflecting the “luxury effect”, where households with a higher socio-economic status had harbour gardens with greater levels of biodiversity. This study showed that affluent gardens displayed far greater diversity, richness and abundance of urban birds. Multivariate analyses confirmed the patterns by highlighting a distinct bird community in the affluent zone, compared to other two socio-economic zones, which housed a second bird community. Furthermore, the main driver of the bird community composition was dominated by vegetation complexity, most notably tree cover within the gardens. Therefore, this study highlighted that patterns of ecological inequality are highly evident in medium-sized towns in South Africa, where older, affluent suburbs households display greater diversity and abundance of birdlife, compared to subsequent socio-economic zones within the study. Prioritisation with regards to the benefits a garden environment brings to urban residents in terms of a connection to nature, access to urban greenery, and relationship to urban wildlife is vital and should be promoted and planned for across all socio-economic zones.
- Full Text:
- Date Issued: 2020
- Authors: Tricam, Shayla
- Date: 2020
- Subjects: Urban ecology (Biology) -- South Africa , Biotic communites -- South Africa , Gardens -- South Africa -- Managemenet , Birds – Ecology – South Africa , Gardening to attract birds -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145314 , vital:38427
- Description: Urban domestic gardens are an often overlooked component of urban green infrastructure, despite their potential to contribute to the preservation of urban biodiversity. As opposed to public greenspaces, private gardens are individually owned and managed, thus act as social-ecological systems, where the cumulative actions of urban residents can scale up to influence ecological patterns and processes on a larger scale. The diversity of fauna and flora within urban gardens provide a range of ecosystem goods and services, as well as less tangible benefits in the form of recreation, education and culture. However, little is known about the contribution of urban domestic gardens to urban biodiversity and its potential conservation value in South Africa. This study investigated urban domestic gardens along a socio-economic gradient in two medium-sized towns, Grahamstown and Port Alfred in the Eastern Cape, South Africa. This study found distinct differences among urban resident garden management practices as well as the avifauna which were seen within the gardens across the socio-economic gradient. The Garden Management Intensity index was higher within affluent households compared to other socio-economic levels, with subsequent management scores not differing statistically along the gradient. While there was variation within garden management practices, as well as the number of residents who participated in supplementary bird feeding, little variation was seen in the activities which were enjoyed by the residents, indicating numerous benefits the garden environment provides for all urban residents. The bird community composition along the socio-economic gradient displayed patterns directly reflecting the “luxury effect”, where households with a higher socio-economic status had harbour gardens with greater levels of biodiversity. This study showed that affluent gardens displayed far greater diversity, richness and abundance of urban birds. Multivariate analyses confirmed the patterns by highlighting a distinct bird community in the affluent zone, compared to other two socio-economic zones, which housed a second bird community. Furthermore, the main driver of the bird community composition was dominated by vegetation complexity, most notably tree cover within the gardens. Therefore, this study highlighted that patterns of ecological inequality are highly evident in medium-sized towns in South Africa, where older, affluent suburbs households display greater diversity and abundance of birdlife, compared to subsequent socio-economic zones within the study. Prioritisation with regards to the benefits a garden environment brings to urban residents in terms of a connection to nature, access to urban greenery, and relationship to urban wildlife is vital and should be promoted and planned for across all socio-economic zones.
- Full Text:
- Date Issued: 2020
A study of contaminants in fish in South Africa : linking science, management and society
- Authors: Ramparsad, Kerina
- Date: 2020
- Subjects: Estuarine fishes -- Contamination -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48609 , vital:40895
- Description: Contaminants in fish is a concern globally and locally. Fish have the propensity to accumulate contaminants to levels that may pose a threat to human health and disrupt ecosystem function. The purpose for investigating contaminants in this study for fish provides the public with information on the potential human health risks from the contaminated fish we consume. This study also investigated contaminants in estuarine fish and sediment, and is important to monitor as these components of ecosystems can indicate contamination in estuaries. Effective methods to determine contaminants in fish and sediment included the Direct Mercury Analyser 80 for mercury, Gas Chromatography for fatty acids and polychlorinated biphenyls and Inductively Coupled Plasma for aluminium, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, vanadium and zinc. Basic statistical tools, geochemical techniques, a bioaccumulation model and human health risk assessment tools provided by the United States Environmental Protection Agency were used to interpret the data. Ultimately consumption advice was developed from the risk assessment results and showed predatory fish such as swordfish and bluenose species are recommended to be avoided while yellow tail, red roman, mackerel, fish fingers and canned tuna are some of the fish that can be eaten 10-14 times per month that would not cause potential health risks. It was found that estuarine ambassid fish investigated in this study were not suitable for contaminant monitoring. There were no clear spatial and seasonal trends observed in the estuaries suggesting that ambassid fish efficiently assimilate contaminants. There was little evidence that contaminants were transferred from sediment to ambassid fish in the eThekwini estuaries. Therefore, their use is limited as a cost-effective estuarine contaminant monitoring tool. Each estuary investigated is unique and requires its own management plan.
- Full Text:
- Date Issued: 2020
- Authors: Ramparsad, Kerina
- Date: 2020
- Subjects: Estuarine fishes -- Contamination -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48609 , vital:40895
- Description: Contaminants in fish is a concern globally and locally. Fish have the propensity to accumulate contaminants to levels that may pose a threat to human health and disrupt ecosystem function. The purpose for investigating contaminants in this study for fish provides the public with information on the potential human health risks from the contaminated fish we consume. This study also investigated contaminants in estuarine fish and sediment, and is important to monitor as these components of ecosystems can indicate contamination in estuaries. Effective methods to determine contaminants in fish and sediment included the Direct Mercury Analyser 80 for mercury, Gas Chromatography for fatty acids and polychlorinated biphenyls and Inductively Coupled Plasma for aluminium, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, vanadium and zinc. Basic statistical tools, geochemical techniques, a bioaccumulation model and human health risk assessment tools provided by the United States Environmental Protection Agency were used to interpret the data. Ultimately consumption advice was developed from the risk assessment results and showed predatory fish such as swordfish and bluenose species are recommended to be avoided while yellow tail, red roman, mackerel, fish fingers and canned tuna are some of the fish that can be eaten 10-14 times per month that would not cause potential health risks. It was found that estuarine ambassid fish investigated in this study were not suitable for contaminant monitoring. There were no clear spatial and seasonal trends observed in the estuaries suggesting that ambassid fish efficiently assimilate contaminants. There was little evidence that contaminants were transferred from sediment to ambassid fish in the eThekwini estuaries. Therefore, their use is limited as a cost-effective estuarine contaminant monitoring tool. Each estuary investigated is unique and requires its own management plan.
- Full Text:
- Date Issued: 2020
A study of why some physic concepts in the South African Physical Science curriculum are poorly understood in order to develop a targeted action-research intervention for Newton’s second law
- Authors: Cobbing, Kathleen Margaret
- Date: 2020
- Subjects: Physics -- Study and teaching (Secondary) -- South Africa , Physics -- Examinations, questions, etc. -- South Africa , Motion -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146903 , vital:38575
- Description: Globally, many students show a poor understanding of concepts in high school physics and lack the necessary problem-solving skills that the course demands. The application of Newton’s second law was found to be particularly problematic through document analysis of South African examination feedback reports, as well as from an analysis of the physics examinations at a pair of well-resourced South African independent schools that follow the Independent Examination Board curriculum. Through an action-research approach, a resource for use by students was designed and modified to improve students’ understanding of this concept, while modelling problemsolving methods. The resource consisted of brief revision notes, worked examples and scaffolded exercises. The design of the resource was influenced by the theory of cognitive apprenticeship, cognitive load theory and conceptual change theory. One of the aims of the resource was to encourage students to translate between the different representations of a problem situation: symbolic, abstract, model and concrete. The impact of this resource was evaluated at a pair of schools using a mixed methods approach. This incorporated pre- and post-tests for a quantitative assessment, qualitative student evaluations and the analysis of examination scripts. There was an improvement from pre- to post-test for all four iterations of the intervention and these improvements were shown to be significant. The use of the resource led to an increase in the quality and quantity of diagrams drawn by students in subsequent assessments.
- Full Text:
- Date Issued: 2020
- Authors: Cobbing, Kathleen Margaret
- Date: 2020
- Subjects: Physics -- Study and teaching (Secondary) -- South Africa , Physics -- Examinations, questions, etc. -- South Africa , Motion -- Study and teaching (Secondary) -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146903 , vital:38575
- Description: Globally, many students show a poor understanding of concepts in high school physics and lack the necessary problem-solving skills that the course demands. The application of Newton’s second law was found to be particularly problematic through document analysis of South African examination feedback reports, as well as from an analysis of the physics examinations at a pair of well-resourced South African independent schools that follow the Independent Examination Board curriculum. Through an action-research approach, a resource for use by students was designed and modified to improve students’ understanding of this concept, while modelling problemsolving methods. The resource consisted of brief revision notes, worked examples and scaffolded exercises. The design of the resource was influenced by the theory of cognitive apprenticeship, cognitive load theory and conceptual change theory. One of the aims of the resource was to encourage students to translate between the different representations of a problem situation: symbolic, abstract, model and concrete. The impact of this resource was evaluated at a pair of schools using a mixed methods approach. This incorporated pre- and post-tests for a quantitative assessment, qualitative student evaluations and the analysis of examination scripts. There was an improvement from pre- to post-test for all four iterations of the intervention and these improvements were shown to be significant. The use of the resource led to an increase in the quality and quantity of diagrams drawn by students in subsequent assessments.
- Full Text:
- Date Issued: 2020
A stunting profile of children under the age of five visiting Bhisho hospital clinic, part of the umbrella project: a profile of stunting in children under the age of five in food insecure villages in Mqanduli, Ngqushwa and Bhisho hospital, Eastern Cape, South Africa
- Authors: Beyleveld, Janine
- Date: 2020
- Subjects: Children -- growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/50201 , vital:42066
- Description: Introduction and Background: Stunting is the most prevalent form of childhood malnutrition where about 149 million children under the age of five can be classified as stunted globally. South Africa has one of the highest stunting rates in the world at 27%, causing devastating effects on economic productivity as well as on an individual’s nutritional status. The presence of stunted growth in children is a strong indicator of chronic undernutrition and highlights injustices experienced within communities. Aims and Objectives: The aim of this study is to develop a stunning profile of children under the age of five, visiting BhishoHospital’s gateway clinic in the Eastern Cape, South Africa. The objectives were to determine the prevalence of stunting of the children visiting Bhisho Hospital’s clinic and to identify the drivers of stunting in the area. Methodology: A quantitative study with a descriptive, cross-sectional design was used. The study population included all children under the age of five visiting Bhisho Hospital’s clinic. Data was collected by means of an interview-administered questionnaire. Results: The prevalence of stunting in the area was 47.5%. A significant association was found between the participants' main form of sanitation and stunting category in the group of infants younger than six months (p = 0.007) and the group older than six months(p = 0.040). Discussion: The prevalence of stunting in the area was far higher than the national average of 27%, although the majority of the sample had a normal weight. The use of non-flush toilets was found to be a risk factor for childhood stunting. Recommendation: Financial and political investment in child health needs to be placed as a top priority in South Africa to reduce stunting rates.
- Full Text:
- Date Issued: 2020
- Authors: Beyleveld, Janine
- Date: 2020
- Subjects: Children -- growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/50201 , vital:42066
- Description: Introduction and Background: Stunting is the most prevalent form of childhood malnutrition where about 149 million children under the age of five can be classified as stunted globally. South Africa has one of the highest stunting rates in the world at 27%, causing devastating effects on economic productivity as well as on an individual’s nutritional status. The presence of stunted growth in children is a strong indicator of chronic undernutrition and highlights injustices experienced within communities. Aims and Objectives: The aim of this study is to develop a stunning profile of children under the age of five, visiting BhishoHospital’s gateway clinic in the Eastern Cape, South Africa. The objectives were to determine the prevalence of stunting of the children visiting Bhisho Hospital’s clinic and to identify the drivers of stunting in the area. Methodology: A quantitative study with a descriptive, cross-sectional design was used. The study population included all children under the age of five visiting Bhisho Hospital’s clinic. Data was collected by means of an interview-administered questionnaire. Results: The prevalence of stunting in the area was 47.5%. A significant association was found between the participants' main form of sanitation and stunting category in the group of infants younger than six months (p = 0.007) and the group older than six months(p = 0.040). Discussion: The prevalence of stunting in the area was far higher than the national average of 27%, although the majority of the sample had a normal weight. The use of non-flush toilets was found to be a risk factor for childhood stunting. Recommendation: Financial and political investment in child health needs to be placed as a top priority in South Africa to reduce stunting rates.
- Full Text:
- Date Issued: 2020
Age of squid Loligo reynaudii d’Orbigny, 1845, and its possible use to test effectiveness of the closed season in protecting this resource
- Mwanangombe, Collette Habani
- Authors: Mwanangombe, Collette Habani
- Date: 2020
- Subjects: Loliginidae -- Spawning -- South Africa , Loliginidae -- Age determination , Loligo fisheries -- South Africa , Fishery management -- South Africa , Otoliths , Loliginidae – Eggs -- Incubation , Loliginidae – Growth , Fish stock assessment -- South Africa , Recruitment (Population biology) -- South Africa , Loligo reynaudii d’Orbigny
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144333 , vital:38336
- Description: This study presents age distributions representing populations of adult Loligo reynaudii, together with the results of spawning and commercial catches to assist in understanding the beneficial role of the closed season. The results were based on 791 samples collected during three closed seasons (November: 2003, 2004 and 2005) and out of closed season during April/May 2005. Age and predicted growth were examined by counting daily rings on statolith microstructures. The age in days after hatching ranged from 168 to 484 days (71-425 mm) in males and from 125 to 478 days (83-263 mm) in females. Average age at spawning was found to be 323 days in males and 316 days in females. Population estimates of growth rates were best described by a linear growth model which revealed that males grew faster than females in length as they grew older with growth rate ranging between 0.63 to 0.83 mm per day for males and between 0.22 to 0.32 mm per day for females. Back-calculated hatch dates and later egg-laying events for parental populations were determined. Results from back calculated egg laying dates (presented as percentage of frequency of all laying dates) indicated a highest total of 36%, 39% and 15% of eggs from all samples were laid during the closed season and nine days after the closed season during year 2003, 2004 and 2005 respectively. Monthly commercial total catches (2002-2005) showed an increase from November soon after the fishery resumed, up until the month of January. Daily catches were highest in November (up to 290 tonnes) relative to the daily catches observed in December and January in all the years. Results led to the conclusion that the closed season (25 October to 22 November) is beneficial for both the chokka resource and the fishery. This is because: a) there is time for enough spawning biomass to accumulate, which subsequently results in high catches (good fishery), in the current year, best immediately after season opens in November; b) there is a link in the results between egg laying dates in the period of closed season and immediately afterwards, and the magnitude of catches in last nine days of November.
- Full Text:
- Date Issued: 2020
- Authors: Mwanangombe, Collette Habani
- Date: 2020
- Subjects: Loliginidae -- Spawning -- South Africa , Loliginidae -- Age determination , Loligo fisheries -- South Africa , Fishery management -- South Africa , Otoliths , Loliginidae – Eggs -- Incubation , Loliginidae – Growth , Fish stock assessment -- South Africa , Recruitment (Population biology) -- South Africa , Loligo reynaudii d’Orbigny
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144333 , vital:38336
- Description: This study presents age distributions representing populations of adult Loligo reynaudii, together with the results of spawning and commercial catches to assist in understanding the beneficial role of the closed season. The results were based on 791 samples collected during three closed seasons (November: 2003, 2004 and 2005) and out of closed season during April/May 2005. Age and predicted growth were examined by counting daily rings on statolith microstructures. The age in days after hatching ranged from 168 to 484 days (71-425 mm) in males and from 125 to 478 days (83-263 mm) in females. Average age at spawning was found to be 323 days in males and 316 days in females. Population estimates of growth rates were best described by a linear growth model which revealed that males grew faster than females in length as they grew older with growth rate ranging between 0.63 to 0.83 mm per day for males and between 0.22 to 0.32 mm per day for females. Back-calculated hatch dates and later egg-laying events for parental populations were determined. Results from back calculated egg laying dates (presented as percentage of frequency of all laying dates) indicated a highest total of 36%, 39% and 15% of eggs from all samples were laid during the closed season and nine days after the closed season during year 2003, 2004 and 2005 respectively. Monthly commercial total catches (2002-2005) showed an increase from November soon after the fishery resumed, up until the month of January. Daily catches were highest in November (up to 290 tonnes) relative to the daily catches observed in December and January in all the years. Results led to the conclusion that the closed season (25 October to 22 November) is beneficial for both the chokka resource and the fishery. This is because: a) there is time for enough spawning biomass to accumulate, which subsequently results in high catches (good fishery), in the current year, best immediately after season opens in November; b) there is a link in the results between egg laying dates in the period of closed season and immediately afterwards, and the magnitude of catches in last nine days of November.
- Full Text:
- Date Issued: 2020
Alternative pine species/hybrids for the Cape timber growing regions of South Africa
- Authors: Van der Hoef, André
- Date: 2020
- Subjects: Species -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47613 , vital:40258
- Description: Pinus radiata has been the preferred commercial sawtimber species for the Cape forestry region for many years. Since the introduction of Fusarium circinatum, and the susceptibility of P. radiata to this disease, the sustainable production of this pine species for the Cape has been negatively impacted due to poor survival in the nursery and in field plantings. For this reason, a number of additional pine species and hybrids have been established in the Cape region of South Africa since 2006 to identify taxa that would perform as well as or better than P. radiata. Three research trials were implemented on contrasting sites that contained eight common species/hybrids treatments that included P. elliottii, P. elliottii x P. caribaea, P. radiata, P. patula x P. greggii var. australis, P. patula x P. oocarpa, P. patula x P. tecunumanii (HE), P. patula x P. tecunumanii (LE) and P. tecunumanii (HE) x P. oocarpa were established at Witelsbos, Kruisfontein and Garcia across diverse soil types, drainage and climate conditions in the Cape. Survival, growth data and tree morphology (forking, foxtails, broken tops and stem form) were assessed at five years of age and individual tree volume was calculated. Five year results indicate that on the waterlogged site at Witelsbos P. elliottii and its hybrid with P. caribaea was best in terms of productivity, at the dry site of Garcia, P. taeda and P. elliottii demonstrated promise, and at Kruisfontein, the most fertile site, P. elliottii x P. caribaea, P. patula x P. tecunumanii (LE) and P. maximinoi were found to be promising alternatives to P. radiata. Wood properties were assessed at Kruisfontein at six-years of age. Basic density and Modulus of Elasticity (MOE) were found to be significantly different for the various species/hybrids. Pinus patula x P. tecunumanii (LE), P. patula x P. greggii (S), P. maximinoi and P. patula x P. tecunumanii (HE) were all significantly better than P. radiata, which would suggest that these taxa would have similar or superior wood strength over P. radiata, the preferred sawtimber species for the Cape region. Only P. tecunumanii (HE) x P. oocarpa had a higher basic density than P. radiata, but not significantly different. Species that had similar basic density were P. patula x P. greggii (S), P. taeda and P. tecunumanii (LE) x P. caribaea. Although P. elliottii x P. caribaea had the highest volume at Witelsbos and Kruisfontein, the timber qualities were the worst, suggesting that some breeding is needed to improve this hybrid to be an acceptable sawtimber species. From this study, several potential alternative species/hybrids have been identified that are tolerant to the F. circinatum pathogen and have acceptable growth and wood properties, compared to P. radiata.
- Full Text:
- Date Issued: 2020
- Authors: Van der Hoef, André
- Date: 2020
- Subjects: Species -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/47613 , vital:40258
- Description: Pinus radiata has been the preferred commercial sawtimber species for the Cape forestry region for many years. Since the introduction of Fusarium circinatum, and the susceptibility of P. radiata to this disease, the sustainable production of this pine species for the Cape has been negatively impacted due to poor survival in the nursery and in field plantings. For this reason, a number of additional pine species and hybrids have been established in the Cape region of South Africa since 2006 to identify taxa that would perform as well as or better than P. radiata. Three research trials were implemented on contrasting sites that contained eight common species/hybrids treatments that included P. elliottii, P. elliottii x P. caribaea, P. radiata, P. patula x P. greggii var. australis, P. patula x P. oocarpa, P. patula x P. tecunumanii (HE), P. patula x P. tecunumanii (LE) and P. tecunumanii (HE) x P. oocarpa were established at Witelsbos, Kruisfontein and Garcia across diverse soil types, drainage and climate conditions in the Cape. Survival, growth data and tree morphology (forking, foxtails, broken tops and stem form) were assessed at five years of age and individual tree volume was calculated. Five year results indicate that on the waterlogged site at Witelsbos P. elliottii and its hybrid with P. caribaea was best in terms of productivity, at the dry site of Garcia, P. taeda and P. elliottii demonstrated promise, and at Kruisfontein, the most fertile site, P. elliottii x P. caribaea, P. patula x P. tecunumanii (LE) and P. maximinoi were found to be promising alternatives to P. radiata. Wood properties were assessed at Kruisfontein at six-years of age. Basic density and Modulus of Elasticity (MOE) were found to be significantly different for the various species/hybrids. Pinus patula x P. tecunumanii (LE), P. patula x P. greggii (S), P. maximinoi and P. patula x P. tecunumanii (HE) were all significantly better than P. radiata, which would suggest that these taxa would have similar or superior wood strength over P. radiata, the preferred sawtimber species for the Cape region. Only P. tecunumanii (HE) x P. oocarpa had a higher basic density than P. radiata, but not significantly different. Species that had similar basic density were P. patula x P. greggii (S), P. taeda and P. tecunumanii (LE) x P. caribaea. Although P. elliottii x P. caribaea had the highest volume at Witelsbos and Kruisfontein, the timber qualities were the worst, suggesting that some breeding is needed to improve this hybrid to be an acceptable sawtimber species. From this study, several potential alternative species/hybrids have been identified that are tolerant to the F. circinatum pathogen and have acceptable growth and wood properties, compared to P. radiata.
- Full Text:
- Date Issued: 2020
An Analysis of Internet Background Radiation within an African IPv4 netblock
- Authors: Hendricks, Wadeegh
- Date: 2020
- Subjects: Computer networks -- Monitoring –- South Africa , Dark Web , Computer networks -- Security measures –- South Africa , Universities and Colleges -- Computer networks -- Security measures , Malware (Computer software) , TCP/IP (Computer network protocol)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103791 , vital:32298
- Description: The use of passive network sensors has in the past proven to be quite effective in monitoring and analysing the current state of traffic on a network. Internet traffic destined to a routable, yet unused address block is often referred to as Internet Background Radiation (IBR) and characterised as unsolicited. This unsolicited traffic is however quite valuable to researchers in that it allows them to study the traffic patterns in a covert manner. IBR is largely composed of network and port scanning traffic, backscatter packets from virus and malware activity and to a lesser extent, misconfiguration of network devices. This research answers the following two questions: (1) What is the current state of IBR within the context of a South African IP address space and (2) Can any anomalies be detected in the traffic, with specific reference to current global malware attacks such as Mirai and similar. Rhodes University operates five IPv4 passive network sensors, commonly known as network telescopes, each monitoring its own /24 IP address block. The oldest of these network telescopes has been collecting traffic for over a decade, with the newest being established in 2011. This research focuses on the in-depth analysis of the traffic captured by one telescope in the 155/8 range over a 12 month period, from January to December 2017. The traffic was analysed and classified according the protocol, TCP flag, source IP address, destination port, packet count and payload size. Apart from the normal network traffic graphs and tables, a geographic heatmap of source traffic was also created, based on the source IP address. Spikes and noticeable variances in traffic patterns were further investigated and evidence of Mirai like malware activity was observed. Network and port scanning were found to comprise the largest amount of traffic, accounting for over 90% of the total IBR. Various scanning techniques were identified, including low level passive scanning and much higher level active scanning.
- Full Text:
- Date Issued: 2020
- Authors: Hendricks, Wadeegh
- Date: 2020
- Subjects: Computer networks -- Monitoring –- South Africa , Dark Web , Computer networks -- Security measures –- South Africa , Universities and Colleges -- Computer networks -- Security measures , Malware (Computer software) , TCP/IP (Computer network protocol)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103791 , vital:32298
- Description: The use of passive network sensors has in the past proven to be quite effective in monitoring and analysing the current state of traffic on a network. Internet traffic destined to a routable, yet unused address block is often referred to as Internet Background Radiation (IBR) and characterised as unsolicited. This unsolicited traffic is however quite valuable to researchers in that it allows them to study the traffic patterns in a covert manner. IBR is largely composed of network and port scanning traffic, backscatter packets from virus and malware activity and to a lesser extent, misconfiguration of network devices. This research answers the following two questions: (1) What is the current state of IBR within the context of a South African IP address space and (2) Can any anomalies be detected in the traffic, with specific reference to current global malware attacks such as Mirai and similar. Rhodes University operates five IPv4 passive network sensors, commonly known as network telescopes, each monitoring its own /24 IP address block. The oldest of these network telescopes has been collecting traffic for over a decade, with the newest being established in 2011. This research focuses on the in-depth analysis of the traffic captured by one telescope in the 155/8 range over a 12 month period, from January to December 2017. The traffic was analysed and classified according the protocol, TCP flag, source IP address, destination port, packet count and payload size. Apart from the normal network traffic graphs and tables, a geographic heatmap of source traffic was also created, based on the source IP address. Spikes and noticeable variances in traffic patterns were further investigated and evidence of Mirai like malware activity was observed. Network and port scanning were found to comprise the largest amount of traffic, accounting for over 90% of the total IBR. Various scanning techniques were identified, including low level passive scanning and much higher level active scanning.
- Full Text:
- Date Issued: 2020
An assessment of temporal changes in selective biological characteristics of chokka squid (Loligo reynaudii d’Órbigny, 1845)
- Authors: Mmethi, Mpho Audrey
- Date: 2020
- Subjects: Loligo reynaudii , Squids -- Morphology , Squids -- South Africa , Squid fisheries -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143516 , vital:38253
- Description: The biological characteristics of chokka squid, Loligo reynaudii, sampled off the south coast of South Africa, were compared between 1994 and 2017 to ascertain any temporal changes using analysis of length frequency (LF) data over 15 years (1996–2017), and mantle length (ML) and total weight (TW) relationships over 9 years (1994–2016). To investigate feeding, two caecum colours were chosen for analysis (white: no food ingested, and yellow: six to seven hours after food ingestion). Other factors were kept constant throughout: similar sampling period of 60 days in spring-summer, similar depths and areas sampled, and identical maturity stage. Anecdotal evidence from fishers suggested that the length frequency and ML_TW relationship of chokka have changed over years, with possibilities to be linked to fishing activities and environmental conditions. Also, there is evidence in the published literature that both fisheries and environment may influence length distributions in populations of fish and cephalopods over time. The results from this study showed no significant differences between length frequencies over the time series. However, a significant decrease in length frequencies between 2014 and 2016 was noted when paired data was analysed by Anova (2014:2015, 2014:2016 and 2015:2016), which was initially noted in kernel density, Figure 2, hence an additional analysis was done. These changes were not linked to sea temperature (at 9 m, 14 m, 18 m, and 21 m depth strata), with not significant (P>0.05) results when temperature was analysed by t-test between 2002 and 2015. There was also a weak correlation between length frequency and the total squid catch in a given year (F Statistic (df = 1; 13) is 3.686 and 5.394 for males and females respectively, R² is 0.221 for males and 0.293 for females), but too weak to interpret, given the lack of other supporting data and the short time series. The ML_TW relationship showed no significant trends between the years for either sex. There was also no correlation between the ML_TW and total squid catch or temperature. A white caecum occurred significantly more often in males than in females (dof = 1; p < 0.05) from General Linear Model (GLM), indicating that the presence of non-feeding males in the spawning grounds may be linked to the behaviour of spawning squid.
- Full Text:
- Date Issued: 2020
- Authors: Mmethi, Mpho Audrey
- Date: 2020
- Subjects: Loligo reynaudii , Squids -- Morphology , Squids -- South Africa , Squid fisheries -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143516 , vital:38253
- Description: The biological characteristics of chokka squid, Loligo reynaudii, sampled off the south coast of South Africa, were compared between 1994 and 2017 to ascertain any temporal changes using analysis of length frequency (LF) data over 15 years (1996–2017), and mantle length (ML) and total weight (TW) relationships over 9 years (1994–2016). To investigate feeding, two caecum colours were chosen for analysis (white: no food ingested, and yellow: six to seven hours after food ingestion). Other factors were kept constant throughout: similar sampling period of 60 days in spring-summer, similar depths and areas sampled, and identical maturity stage. Anecdotal evidence from fishers suggested that the length frequency and ML_TW relationship of chokka have changed over years, with possibilities to be linked to fishing activities and environmental conditions. Also, there is evidence in the published literature that both fisheries and environment may influence length distributions in populations of fish and cephalopods over time. The results from this study showed no significant differences between length frequencies over the time series. However, a significant decrease in length frequencies between 2014 and 2016 was noted when paired data was analysed by Anova (2014:2015, 2014:2016 and 2015:2016), which was initially noted in kernel density, Figure 2, hence an additional analysis was done. These changes were not linked to sea temperature (at 9 m, 14 m, 18 m, and 21 m depth strata), with not significant (P>0.05) results when temperature was analysed by t-test between 2002 and 2015. There was also a weak correlation between length frequency and the total squid catch in a given year (F Statistic (df = 1; 13) is 3.686 and 5.394 for males and females respectively, R² is 0.221 for males and 0.293 for females), but too weak to interpret, given the lack of other supporting data and the short time series. The ML_TW relationship showed no significant trends between the years for either sex. There was also no correlation between the ML_TW and total squid catch or temperature. A white caecum occurred significantly more often in males than in females (dof = 1; p < 0.05) from General Linear Model (GLM), indicating that the presence of non-feeding males in the spawning grounds may be linked to the behaviour of spawning squid.
- Full Text:
- Date Issued: 2020
An assessment of the effectiveness of the Crossways Farm Village constructed wetland in the treatment of domestic wastewater
- Authors: Silbernagl, Ryan
- Date: 2020
- Subjects: Crossways Farm Village FWS wetland (South Africa)-- Management , Sewage -- Purification -- South Africa , Wetland management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145011 , vital:38400
- Description: A mass balance study was conducted comparing inflowing and outflowing solute loads in order to calculate the treatment efficiency of a free water surface (FWS) constructed wetland used to treat domestic wastewater following primary treatment in an anaerobic reactor and oxidation in a rotating biological contractor. Water samples were taken at six locations down the length of the treatment system and analysed for nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), ammonia nitrogen (NH4-N) and phosphorus as phosphate (PO4-P). Flow was determined using two V notch weirs combined with pressure transducers based on an empirically derived stage-discharge relationship. The concentration of each solute (g.m-3) multiplied by flow (m3.day-1) provides a measurement of the mass of each solute entering and leaving the treatment wetland such that the difference (inflow – outflow) indicates the nett storage in, or loss from, the wetland. In order to determine the water balance, apart from measuring surface inflows and outflows, rainfall was measured using an onsite rain gauge. Evapotranspirational losses were determined using the Penman-Monteith equation based on weather data collected at an onsite weather station. Other than water that entered the wetland via the primary water treatment works, surface inflows could be ignored as the wetland was sealed with a plastic liner, which also prevented groundwater inflow and outflow. Wetland outputs via surface outflow and evapotranspiration were then subtracted from wetland inputs to determine the water balance over the study period. Approximately 10.5% of water inputs into the hydrological mass balance calculation was not accounted for, which is considered to be accounted for by inaccuracy associated with the estimation of evapotranspiration and possibly by differences in water levels in the wetland at the start and end of the experiment. Total input, output and storage of NO3-N, NO2-N, NH4-N and PO4-P was calculated from April 2016 to September 2016 to give the treatment efficiency of the FWS wetland system. Results showed a 91.5% reduction in NO3-N, 76.6% reduction in NH4-N, and 88.8% reduction in PO4P between the inflow and outflow. Wetland sediment and vegetation (Typha capensis) samples were also analysed for nitrogen and phosphorus content to give an estimate of nutrient stocks/storage accumulated in plant tissues and sediments over the lifespan of the wetland. Standing stock calculations showed that a total of 450.1kg of nitrogen is stored in the wetlands, of which 69.3kg is stored in wetland sediments. Wetland phosphorus retention was found to be significantly lower with a total of 57.1kg of phosphorus, of which 77.4% was stored in sediments, indicating that wetland sediments comprise the largest store and therefore removal pathway of nutrients in the Crossways Farm Village FWS wetland.
- Full Text:
- Date Issued: 2020
- Authors: Silbernagl, Ryan
- Date: 2020
- Subjects: Crossways Farm Village FWS wetland (South Africa)-- Management , Sewage -- Purification -- South Africa , Wetland management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145011 , vital:38400
- Description: A mass balance study was conducted comparing inflowing and outflowing solute loads in order to calculate the treatment efficiency of a free water surface (FWS) constructed wetland used to treat domestic wastewater following primary treatment in an anaerobic reactor and oxidation in a rotating biological contractor. Water samples were taken at six locations down the length of the treatment system and analysed for nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), ammonia nitrogen (NH4-N) and phosphorus as phosphate (PO4-P). Flow was determined using two V notch weirs combined with pressure transducers based on an empirically derived stage-discharge relationship. The concentration of each solute (g.m-3) multiplied by flow (m3.day-1) provides a measurement of the mass of each solute entering and leaving the treatment wetland such that the difference (inflow – outflow) indicates the nett storage in, or loss from, the wetland. In order to determine the water balance, apart from measuring surface inflows and outflows, rainfall was measured using an onsite rain gauge. Evapotranspirational losses were determined using the Penman-Monteith equation based on weather data collected at an onsite weather station. Other than water that entered the wetland via the primary water treatment works, surface inflows could be ignored as the wetland was sealed with a plastic liner, which also prevented groundwater inflow and outflow. Wetland outputs via surface outflow and evapotranspiration were then subtracted from wetland inputs to determine the water balance over the study period. Approximately 10.5% of water inputs into the hydrological mass balance calculation was not accounted for, which is considered to be accounted for by inaccuracy associated with the estimation of evapotranspiration and possibly by differences in water levels in the wetland at the start and end of the experiment. Total input, output and storage of NO3-N, NO2-N, NH4-N and PO4-P was calculated from April 2016 to September 2016 to give the treatment efficiency of the FWS wetland system. Results showed a 91.5% reduction in NO3-N, 76.6% reduction in NH4-N, and 88.8% reduction in PO4P between the inflow and outflow. Wetland sediment and vegetation (Typha capensis) samples were also analysed for nitrogen and phosphorus content to give an estimate of nutrient stocks/storage accumulated in plant tissues and sediments over the lifespan of the wetland. Standing stock calculations showed that a total of 450.1kg of nitrogen is stored in the wetlands, of which 69.3kg is stored in wetland sediments. Wetland phosphorus retention was found to be significantly lower with a total of 57.1kg of phosphorus, of which 77.4% was stored in sediments, indicating that wetland sediments comprise the largest store and therefore removal pathway of nutrients in the Crossways Farm Village FWS wetland.
- Full Text:
- Date Issued: 2020
An ergonomics approach to understanding perceived barriers to the provision of high-quality healthcare: a Sarah Baartman District clinics case study
- Authors: Card, Jason
- Date: 2020
- Subjects: Medical care -- South Africa -- Eastern Cape , Public health -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/170536 , vital:41933
- Description: Background:The complex nature of healthcare systemsoftenresultsinthe emergence of context-specific barriers that limit the ability for healthcare stakeholders to ensure safe and effective care delivery. In low-to middle-income (LMIC) countries, such as South Africa (SA), limited financial, material and human resources coupled withpoor infrastructure and poor public health determinants, includingpoverty andpoor education, affectthe ability to maintain andimprove on quality care outcomes.Understanding what different stakeholders perceive as barriers, and if these barriers are understood at different levels, is therefore important when attempting to mitigate the risk for unsafe or inefficient care delivery. Human Factors and Ergonomics (HFE) adoptssystems and participatory approaches for the exploration, analysis, and design of socio-technical systems to optimize both human wellbeing and system performance.The barriers to safe and effective healthcare delivery, from an HFE perspective, are not known in the South African context, particularly in parts of the Eastern Cape Province. Elucidatingthesebarriers, even if self-reported,may guidefuture efforts aimed at mitigating risks.The purpose of this study, therefore,wasto explore and highlight the perceived systemic barriers to local and national healthcare delivery, within the Sarah Baartman District in the Eastern Cape Province of South Africa.Methods: Ashort discussion aimed at introducing HFE and components of the Work Systems Model, followed by a survey that captured participant demographics, job characteristics, the perceived national and local systemic barriers, and proposed solutions, was administered withhealthcare stakeholders from 14 primary healthcare facilities and 1 department office within the Sarah Baartman District.Participants (n=120) included management, pharmacy, administration, maintenance, community-and home-based care and nursing staff.Data from the surveys were thematically analysed and categorised according to components of the work system model (Carayon, 2009) and respective workgroup.Results: The findings revealed many overlapping,systemic barriersthat includedshortages of staff, poor management and leadership, a lack of equipmentand basic necessities, poor infrastructure, patient complexity,and high workloads. The results further indicate that the way in which the reported barriers affect worksystem interactionsand performance are unique to different workgroups. Stakeholders iiproposedthat,among others, the absorption of contract workers, the provision of training and adequate human and medical resources and the maintenance of facilities may mitigate the barriers and improve healthcare delivery.Conclusion: The findings highlight a myriad of perceived systemic barriers perceived in the Sarah Baartman district, some of which were fundamental for the effective function of any healthcare system. These barriers may have wide-spread implications for stakeholders at all levels, ultimately affecting the performance, satisfaction and safety and the quality of care. It is especially important to consider these barriers in light of the COVID-19 epidemic, which emerged throughout this study and the major threat it presents to South African healthcare systems. Future research should aim to explore how these barriers interact to contribute to processes and outcomes, as well as explore the perceptions at provincial and national levels in order to better identify areas and strategies for improvement.
- Full Text:
- Date Issued: 2020
- Authors: Card, Jason
- Date: 2020
- Subjects: Medical care -- South Africa -- Eastern Cape , Public health -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/170536 , vital:41933
- Description: Background:The complex nature of healthcare systemsoftenresultsinthe emergence of context-specific barriers that limit the ability for healthcare stakeholders to ensure safe and effective care delivery. In low-to middle-income (LMIC) countries, such as South Africa (SA), limited financial, material and human resources coupled withpoor infrastructure and poor public health determinants, includingpoverty andpoor education, affectthe ability to maintain andimprove on quality care outcomes.Understanding what different stakeholders perceive as barriers, and if these barriers are understood at different levels, is therefore important when attempting to mitigate the risk for unsafe or inefficient care delivery. Human Factors and Ergonomics (HFE) adoptssystems and participatory approaches for the exploration, analysis, and design of socio-technical systems to optimize both human wellbeing and system performance.The barriers to safe and effective healthcare delivery, from an HFE perspective, are not known in the South African context, particularly in parts of the Eastern Cape Province. Elucidatingthesebarriers, even if self-reported,may guidefuture efforts aimed at mitigating risks.The purpose of this study, therefore,wasto explore and highlight the perceived systemic barriers to local and national healthcare delivery, within the Sarah Baartman District in the Eastern Cape Province of South Africa.Methods: Ashort discussion aimed at introducing HFE and components of the Work Systems Model, followed by a survey that captured participant demographics, job characteristics, the perceived national and local systemic barriers, and proposed solutions, was administered withhealthcare stakeholders from 14 primary healthcare facilities and 1 department office within the Sarah Baartman District.Participants (n=120) included management, pharmacy, administration, maintenance, community-and home-based care and nursing staff.Data from the surveys were thematically analysed and categorised according to components of the work system model (Carayon, 2009) and respective workgroup.Results: The findings revealed many overlapping,systemic barriersthat includedshortages of staff, poor management and leadership, a lack of equipmentand basic necessities, poor infrastructure, patient complexity,and high workloads. The results further indicate that the way in which the reported barriers affect worksystem interactionsand performance are unique to different workgroups. Stakeholders iiproposedthat,among others, the absorption of contract workers, the provision of training and adequate human and medical resources and the maintenance of facilities may mitigate the barriers and improve healthcare delivery.Conclusion: The findings highlight a myriad of perceived systemic barriers perceived in the Sarah Baartman district, some of which were fundamental for the effective function of any healthcare system. These barriers may have wide-spread implications for stakeholders at all levels, ultimately affecting the performance, satisfaction and safety and the quality of care. It is especially important to consider these barriers in light of the COVID-19 epidemic, which emerged throughout this study and the major threat it presents to South African healthcare systems. Future research should aim to explore how these barriers interact to contribute to processes and outcomes, as well as explore the perceptions at provincial and national levels in order to better identify areas and strategies for improvement.
- Full Text:
- Date Issued: 2020
An exploration of the overlap between open source threat intelligence and active internet background radiation
- Authors: Pearson, Deon Turner
- Date: 2020
- Subjects: Computer networks -- Security measures , Computer networks -- Monitoring , Malware (Computer software) , TCP/IP (Computer network protocol) , Open source intelligence
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103802 , vital:32299
- Description: Organisations and individuals are facing increasing persistent threats on the Internet from worms, port scanners, and malicious software (malware). These threats are constantly evolving as attack techniques are discovered. To aid in the detection and prevention of such threats, and to stay ahead of the adversaries conducting the attacks, security specialists are utilising Threat Intelligence (TI) data in their defense strategies. TI data can be obtained from a variety of different sources such as private routers, firewall logs, public archives, and public or private network telescopes. However, at the rate and ease at which TI is produced and published, specifically Open Source Threat Intelligence (OSINT), the quality is dropping, resulting in fragmented, context-less and variable data. This research utilised two sets of TI data, a collection of OSINT and active Internet Background Radiation (IBR). The data was collected over a period of 12 months, from 37 publicly available OSINT datasets and five IBR datasets. Through the identification and analysis of common data between the OSINT and IBR datasets, this research was able to gain insight into how effective OSINT is at detecting and potentially reducing ongoing malicious Internet traffic. As part of this research, a minimal framework for the collection, processing/analysis, and distribution of OSINT was developed and tested. The research focused on exploring areas in common between the two datasets, with the intention of creating an enriched, contextualised, and reduced set of malicious source IP addresses that could be published for consumers to use in their own environment. The findings of this research pointed towards a persistent group of IP addresses observed on both datasets, over the period under research. Using these persistent IP addresses, the research was able to identify specific services being targeted. Amongst these persistent IP addresses were significant packets from Mirai like IoT Malware on port 23/tcp and 2323/tcp as well as general scanning activity on port 445/TCP.
- Full Text:
- Date Issued: 2020
- Authors: Pearson, Deon Turner
- Date: 2020
- Subjects: Computer networks -- Security measures , Computer networks -- Monitoring , Malware (Computer software) , TCP/IP (Computer network protocol) , Open source intelligence
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103802 , vital:32299
- Description: Organisations and individuals are facing increasing persistent threats on the Internet from worms, port scanners, and malicious software (malware). These threats are constantly evolving as attack techniques are discovered. To aid in the detection and prevention of such threats, and to stay ahead of the adversaries conducting the attacks, security specialists are utilising Threat Intelligence (TI) data in their defense strategies. TI data can be obtained from a variety of different sources such as private routers, firewall logs, public archives, and public or private network telescopes. However, at the rate and ease at which TI is produced and published, specifically Open Source Threat Intelligence (OSINT), the quality is dropping, resulting in fragmented, context-less and variable data. This research utilised two sets of TI data, a collection of OSINT and active Internet Background Radiation (IBR). The data was collected over a period of 12 months, from 37 publicly available OSINT datasets and five IBR datasets. Through the identification and analysis of common data between the OSINT and IBR datasets, this research was able to gain insight into how effective OSINT is at detecting and potentially reducing ongoing malicious Internet traffic. As part of this research, a minimal framework for the collection, processing/analysis, and distribution of OSINT was developed and tested. The research focused on exploring areas in common between the two datasets, with the intention of creating an enriched, contextualised, and reduced set of malicious source IP addresses that could be published for consumers to use in their own environment. The findings of this research pointed towards a persistent group of IP addresses observed on both datasets, over the period under research. Using these persistent IP addresses, the research was able to identify specific services being targeted. Amongst these persistent IP addresses were significant packets from Mirai like IoT Malware on port 23/tcp and 2323/tcp as well as general scanning activity on port 445/TCP.
- Full Text:
- Date Issued: 2020
An explorative study of Makana local football association coaches characteristics, experiences and needs
- Authors: Callow, Gavin
- Date: 2020
- Subjects: Makana Local Football Association (South Africa) , Football -- Coaching -- South Africa , Football coaches -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138785 , vital:37672
- Description: Introduction: Sports participation has been associated with a number of benefits to young athletes, outside of purely physical health. One of the key components of a successful sports talent identification and development program is effective coaching. A foundation of effective coaching is the coach’s knowledge which can be developed through formal, non-formal and informal means of education. The majority of coach education literature has however focused on coaches from developed countries. Limited studies have looked at the educational experiences and needs of South African coaches, particularly football coaches. The purpose of the current investigation is to establish Local Football Association (LFA) coaches’ perceptions of their educational backgrounds and what knowledge they deem important to be effective coaches. Method: A mixed methods approach was used in which (n=25) Makana LFA coaches answered a questionnaire with the aim of identifying their educational histories and what their current educational needs were. A semi-structured interview was also implemented in which some of the respondents (n=4) were asked more in-depth questions around the same topics, to create a more complete coaching profile. Results: The questionnaire responses highlighted that only 8% of the coaches possess a formal coaching qualification and all of the coaches work on a volunteer basis. Previous experience as a player is the chief source of knowledge for Makana LFA coaches. Not having enough available time is the main perceived barrier for 56% of participants to seeking out further educational opportunities. Fundamentals of coaching was selected by 56% of the coaches as a key subject they want to learn more about. Findings from the interview demonstrate that participants coach multiple teams and often have to rely on senior players to take up assistant coach positions, as well as managing their time effectively to work with all their teams. Informal education is the main source of information for the coaches which includes asking for advice, reading coaching manuals or having a mentor. The coaches value all 3 forms of education, however non-formal workshops are favoured. This is due to all of the coaches already having some form of informal learning experience and formal learning opportunities being too costly to pursue. A combination of lectures, practical sessions and group discussions is desired as a delivery method of coaching knowledge. Discussion: The level of coaching qualifications in the LFA is low, this may have significant implications for talent identification and development in the Sarah Baartman region. All the coaches are volunteer coaches, who primarily rely on informal means of coaching education. ‘Time’ was indicated to be a major barrier, to coaches seeking out educational opportunities. Coaches indicated that they would benefit from a coaching program if it took into consideration their needs, such as wanting to learn more about interpersonal and intrapersonal awareness. Conclusion: If local coaching programs are to be effective, they must reflect the educational needs of their community.
- Full Text:
- Date Issued: 2020
- Authors: Callow, Gavin
- Date: 2020
- Subjects: Makana Local Football Association (South Africa) , Football -- Coaching -- South Africa , Football coaches -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/138785 , vital:37672
- Description: Introduction: Sports participation has been associated with a number of benefits to young athletes, outside of purely physical health. One of the key components of a successful sports talent identification and development program is effective coaching. A foundation of effective coaching is the coach’s knowledge which can be developed through formal, non-formal and informal means of education. The majority of coach education literature has however focused on coaches from developed countries. Limited studies have looked at the educational experiences and needs of South African coaches, particularly football coaches. The purpose of the current investigation is to establish Local Football Association (LFA) coaches’ perceptions of their educational backgrounds and what knowledge they deem important to be effective coaches. Method: A mixed methods approach was used in which (n=25) Makana LFA coaches answered a questionnaire with the aim of identifying their educational histories and what their current educational needs were. A semi-structured interview was also implemented in which some of the respondents (n=4) were asked more in-depth questions around the same topics, to create a more complete coaching profile. Results: The questionnaire responses highlighted that only 8% of the coaches possess a formal coaching qualification and all of the coaches work on a volunteer basis. Previous experience as a player is the chief source of knowledge for Makana LFA coaches. Not having enough available time is the main perceived barrier for 56% of participants to seeking out further educational opportunities. Fundamentals of coaching was selected by 56% of the coaches as a key subject they want to learn more about. Findings from the interview demonstrate that participants coach multiple teams and often have to rely on senior players to take up assistant coach positions, as well as managing their time effectively to work with all their teams. Informal education is the main source of information for the coaches which includes asking for advice, reading coaching manuals or having a mentor. The coaches value all 3 forms of education, however non-formal workshops are favoured. This is due to all of the coaches already having some form of informal learning experience and formal learning opportunities being too costly to pursue. A combination of lectures, practical sessions and group discussions is desired as a delivery method of coaching knowledge. Discussion: The level of coaching qualifications in the LFA is low, this may have significant implications for talent identification and development in the Sarah Baartman region. All the coaches are volunteer coaches, who primarily rely on informal means of coaching education. ‘Time’ was indicated to be a major barrier, to coaches seeking out educational opportunities. Coaches indicated that they would benefit from a coaching program if it took into consideration their needs, such as wanting to learn more about interpersonal and intrapersonal awareness. Conclusion: If local coaching programs are to be effective, they must reflect the educational needs of their community.
- Full Text:
- Date Issued: 2020
An in silico analysis, purification and partial kinetic characterisation of a serine protease from Gelidium pristoides
- Authors: Ntsata, Zolani
- Date: 2020
- Subjects: Gelidium Proteolytic enzymes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12076 , vital:39149
- Description: The aim of this study was to characterize the protease enzyme (s) from red algae. An in silico analysis of red algae genomes was used to identify gene coding for protease. Protease sequences identified from these genomes were examined for conserved domains, active site and structures. The domain search revealed that the identified sequences were from the five classes of protease enzymes. For function inference, the red algae sequences were aligned to identify the catalytic sites, and the tertiary structures were predicted using homology modelling. An in silico analysis provides an indication of the class and potential functions of the enzymes. However, it cannot predict whether the gene is constitutively expressed in the red algae or under which conditions it may be induced, and it cannot determine the kinetic efficiency of an enzyme against various substrate, or the optimum conditions for the protein activity. Attempts to clone and recombinantly express selected red algae proteases, proved unsuccessful, as the available genomes where from red algae species found mainly in Asia, and the designed primers, therefore, did not amplify a corresponding PCR product from the red algae harvested in South Africa. Crude extracts of red algae collected from Kenton-on-Sea, along the East Coast of South Africa, were screened for protease activity using Benzoyl-Arginine-pNitroAnilide (BApNA) as substrate. The proteases detected in the crude extract were purified using ammonium sulphate precipitation and HiPrep DEAE FF 16/10; CM FF 16/10, and HiPrep Q FF 16/10 columns for ion-exchange chromatography. The HiPrep Q FF 16/10 column yielded active protein, which revealed two bands of 11kDa and 17kDa on SDS-PAGE. It was assumed that these bands represented two subunits of the purified protease. Kinetic characterisation of the purified protease revealed a pH optimum of 9, using BApNA as substrate, a temperature optimum at 60ºC, and sensitivity to temperature when stored above 4ºC. The protease activity was inhibited by Ferric chloride (32%), induced by calcium chloride (156%), no inhibition by magnesium chloride (97%) and slight inhibition by potassium chloride (77%) and manganese chloride (70%). Phenylmethylsulfonyl fluoride (PMSF), a serine protease inhibitor, almost totally inhibited the protease activity, indicating that the protease from red algae was most likely a serine protease. The Km and kcat values were 1.96 µM, and 0.364 s -1 , respectively using BApNA as the substrate. This study revealed that the red algae genome contains numerous genes that encode for proteases from almost all the classes of proteases. A serine protease from the red algae Gelidium pristoides was partially purified and kinetically characterised, confirming that red algae found along the Eastern Coast of South Africa contain genes that express active proteases that may be of medical or industrial interest. Further studies, however, are required to recombinantly express, purify and characterise the numerous proteases encoded by the genes identified in the in silico analysis of this study.
- Full Text:
- Date Issued: 2020
- Authors: Ntsata, Zolani
- Date: 2020
- Subjects: Gelidium Proteolytic enzymes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12076 , vital:39149
- Description: The aim of this study was to characterize the protease enzyme (s) from red algae. An in silico analysis of red algae genomes was used to identify gene coding for protease. Protease sequences identified from these genomes were examined for conserved domains, active site and structures. The domain search revealed that the identified sequences were from the five classes of protease enzymes. For function inference, the red algae sequences were aligned to identify the catalytic sites, and the tertiary structures were predicted using homology modelling. An in silico analysis provides an indication of the class and potential functions of the enzymes. However, it cannot predict whether the gene is constitutively expressed in the red algae or under which conditions it may be induced, and it cannot determine the kinetic efficiency of an enzyme against various substrate, or the optimum conditions for the protein activity. Attempts to clone and recombinantly express selected red algae proteases, proved unsuccessful, as the available genomes where from red algae species found mainly in Asia, and the designed primers, therefore, did not amplify a corresponding PCR product from the red algae harvested in South Africa. Crude extracts of red algae collected from Kenton-on-Sea, along the East Coast of South Africa, were screened for protease activity using Benzoyl-Arginine-pNitroAnilide (BApNA) as substrate. The proteases detected in the crude extract were purified using ammonium sulphate precipitation and HiPrep DEAE FF 16/10; CM FF 16/10, and HiPrep Q FF 16/10 columns for ion-exchange chromatography. The HiPrep Q FF 16/10 column yielded active protein, which revealed two bands of 11kDa and 17kDa on SDS-PAGE. It was assumed that these bands represented two subunits of the purified protease. Kinetic characterisation of the purified protease revealed a pH optimum of 9, using BApNA as substrate, a temperature optimum at 60ºC, and sensitivity to temperature when stored above 4ºC. The protease activity was inhibited by Ferric chloride (32%), induced by calcium chloride (156%), no inhibition by magnesium chloride (97%) and slight inhibition by potassium chloride (77%) and manganese chloride (70%). Phenylmethylsulfonyl fluoride (PMSF), a serine protease inhibitor, almost totally inhibited the protease activity, indicating that the protease from red algae was most likely a serine protease. The Km and kcat values were 1.96 µM, and 0.364 s -1 , respectively using BApNA as the substrate. This study revealed that the red algae genome contains numerous genes that encode for proteases from almost all the classes of proteases. A serine protease from the red algae Gelidium pristoides was partially purified and kinetically characterised, confirming that red algae found along the Eastern Coast of South Africa contain genes that express active proteases that may be of medical or industrial interest. Further studies, however, are required to recombinantly express, purify and characterise the numerous proteases encoded by the genes identified in the in silico analysis of this study.
- Full Text:
- Date Issued: 2020
An initial investigation into biological control options for Schinus terebinthifolia in South Africa
- Magengelele, Nwabisa Laurencia
- Authors: Magengelele, Nwabisa Laurencia
- Date: 2020
- Subjects: Anacardiaceae -- Biological control -- South Africa , Plants, Ornamental -- South Africa , Invasive plants -- Biological control -- South Africa , Insects as biological pest control agents -- South Africa , Brazilian pepper tree -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103835 , vital:32306
- Description: Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian pepper tree) is a native tree to subtropical South America that was introduced into South Africa as an ornamental plant. Globally, it is regarded as one of the world’s worst invasive trees. In South Africa, this aggressive pioneer species is becoming increasingly problematic and is being considered as a target for biological control. In South Africa the tree has acquired a native seed-feeding wasp, Megastigmus transvaalensis Hussey (Hymenoptera: Torymidae). The wasp’s native hosts are indigenous Rhus species (Anacardiaceae), but it has expanded its host range to form a new association with both S. terebinthifolia and its close relative S. molle L. (Anacardiaceae). In order to quantify the seed predation by M. transvaalensis on S. terebinthifolia seeds, tree populations were surveyed across the Eastern Cape and KwaZulu-Natal provinces. The wasp was present at 99% of the S. terebinthifolia populations with an average of 22% of the seeds being destroyed. In the Eastern Cape Province, the highest seed damage occurred at the start of the winter months, when about 35% of seeds were damaged. This fell to less than 12% in spring and summer when the plants were flowering. Megastigmus transvaalensis may have slowed the rate of spread of the plant, but it is unlikely to reduce population sizes of S. terebinthifolia in South Africa in the long-term. Biological control efforts can be assisted by knowing the origin and invasion history of the target species. Genetic analyses are often the only way to elucidate the invasion history of invasive alien plants because it is rare to find detailed records of plant introductions. Both microsatellite and chloroplast DNA analysis were conducted on S. terebinthifolia trees from the plant’s introduced distribution in South Africa and both Florida and Hawaii, USA. These samples were compared to plants from the native distribution of South America. The analysis indicated that the S. terebinthifolia in South Africa was most likely sourced from the state of Rio de Janeiro in Brazil, which is the same source of the invasive populations in Florida and Hawaii. Importantly, the South African populations were all found to be “haplotype A”. Plants samples collected from Hawaii USA were the closest match to the South African plants. Biological control agents known to damage haplotype A which have been considered for use in Hawaii and Florida should therefore be prioritised for South Africa. Schinus terebinthifolia has a broad distribution in South Africa; however, the majority of the current distribution is limited to the coastal regions along the eastern coast in KwaZulu-Natal Province. This suggests that the species may be climatically limited. Species distribution models in MaxEnt were used to predict the suitable ecological niche of the species. Using occurrence localities from both the native and invaded range to calibrate the models resulted in 56% of the modelled areas being considered suitable for the growth of S. terebinthifolia in South Africa. This included areas in the Eastern Cape, Western Cape and Limpopo provinces. When the models were calibrated using just the native range data, or just the invaded range data, predicted distributions were more restricted and limited to the coastal areas of the Eastern Cape and KwaZulu-Natal provinces. The coastal areas between Florianopolis and Santos in Brazil were highlighted as the most climatically similar to the invasive populations of S. terebinthifolia in South Africa. These areas should be prioritised if native range surveys for potential biological control agents are conducted in South America. Although the native seed-feeding wasp is damaging to S. terebinthifolia in South Africa, the tree is still not under suitable levels of biological control and is likely to spread and increase in density. New biological control agents are therefore required. Genetic and climatic matching has determined where the most appropriate region to collect new potential biological control agents is. The genetic matching data has also indicated that biological control agents that have been released, or are being considered for release, in Hawaii and Florida, are likely to be suitable for the South African plants because they have been shown to be damaging to ‘haplotype A’. These agents should therefore be the first to be considered for release in South Africa.
- Full Text:
- Date Issued: 2020
An initial investigation into biological control options for Schinus terebinthifolia in South Africa
- Authors: Magengelele, Nwabisa Laurencia
- Date: 2020
- Subjects: Anacardiaceae -- Biological control -- South Africa , Plants, Ornamental -- South Africa , Invasive plants -- Biological control -- South Africa , Insects as biological pest control agents -- South Africa , Brazilian pepper tree -- Biological control -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103835 , vital:32306
- Description: Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian pepper tree) is a native tree to subtropical South America that was introduced into South Africa as an ornamental plant. Globally, it is regarded as one of the world’s worst invasive trees. In South Africa, this aggressive pioneer species is becoming increasingly problematic and is being considered as a target for biological control. In South Africa the tree has acquired a native seed-feeding wasp, Megastigmus transvaalensis Hussey (Hymenoptera: Torymidae). The wasp’s native hosts are indigenous Rhus species (Anacardiaceae), but it has expanded its host range to form a new association with both S. terebinthifolia and its close relative S. molle L. (Anacardiaceae). In order to quantify the seed predation by M. transvaalensis on S. terebinthifolia seeds, tree populations were surveyed across the Eastern Cape and KwaZulu-Natal provinces. The wasp was present at 99% of the S. terebinthifolia populations with an average of 22% of the seeds being destroyed. In the Eastern Cape Province, the highest seed damage occurred at the start of the winter months, when about 35% of seeds were damaged. This fell to less than 12% in spring and summer when the plants were flowering. Megastigmus transvaalensis may have slowed the rate of spread of the plant, but it is unlikely to reduce population sizes of S. terebinthifolia in South Africa in the long-term. Biological control efforts can be assisted by knowing the origin and invasion history of the target species. Genetic analyses are often the only way to elucidate the invasion history of invasive alien plants because it is rare to find detailed records of plant introductions. Both microsatellite and chloroplast DNA analysis were conducted on S. terebinthifolia trees from the plant’s introduced distribution in South Africa and both Florida and Hawaii, USA. These samples were compared to plants from the native distribution of South America. The analysis indicated that the S. terebinthifolia in South Africa was most likely sourced from the state of Rio de Janeiro in Brazil, which is the same source of the invasive populations in Florida and Hawaii. Importantly, the South African populations were all found to be “haplotype A”. Plants samples collected from Hawaii USA were the closest match to the South African plants. Biological control agents known to damage haplotype A which have been considered for use in Hawaii and Florida should therefore be prioritised for South Africa. Schinus terebinthifolia has a broad distribution in South Africa; however, the majority of the current distribution is limited to the coastal regions along the eastern coast in KwaZulu-Natal Province. This suggests that the species may be climatically limited. Species distribution models in MaxEnt were used to predict the suitable ecological niche of the species. Using occurrence localities from both the native and invaded range to calibrate the models resulted in 56% of the modelled areas being considered suitable for the growth of S. terebinthifolia in South Africa. This included areas in the Eastern Cape, Western Cape and Limpopo provinces. When the models were calibrated using just the native range data, or just the invaded range data, predicted distributions were more restricted and limited to the coastal areas of the Eastern Cape and KwaZulu-Natal provinces. The coastal areas between Florianopolis and Santos in Brazil were highlighted as the most climatically similar to the invasive populations of S. terebinthifolia in South Africa. These areas should be prioritised if native range surveys for potential biological control agents are conducted in South America. Although the native seed-feeding wasp is damaging to S. terebinthifolia in South Africa, the tree is still not under suitable levels of biological control and is likely to spread and increase in density. New biological control agents are therefore required. Genetic and climatic matching has determined where the most appropriate region to collect new potential biological control agents is. The genetic matching data has also indicated that biological control agents that have been released, or are being considered for release, in Hawaii and Florida, are likely to be suitable for the South African plants because they have been shown to be damaging to ‘haplotype A’. These agents should therefore be the first to be considered for release in South Africa.
- Full Text:
- Date Issued: 2020
An investigation into the application of Distributed Endpoint Processing to 3D Immersive Audio Rendering
- Authors: Devonport, Robin Sean
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163258 , vital:41022
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Computer Science, 2020.
- Full Text:
- Date Issued: 2020
- Authors: Devonport, Robin Sean
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163258 , vital:41022
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Computer Science, 2020.
- Full Text:
- Date Issued: 2020
An investigation into the fire regimes of the upper Tsitsa River catchment
- Authors: Snyman, Gareth
- Date: 2020
- Subjects: Prescribed burning -- Environmental aspects -- South Africa , Fire ecology -- South Africa , Tsitsa River catchment (South Africa) , Soil erosion -- South Africa , Grasslands -- Management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145256 , vital:38422
- Description: South African grasslands are rich in flora and fauna and are a dominant vegetation cover in many of the water catchment areas, while providing a multitude of services to local communities and the environment. Fires have been the primary tool used to manage grasslands for livestock production for many years. However, there is debate about how they impact and alter landscapes and there are two schools of thought throughout literature. One argument is that fires are detrimental to landscapes; altering hydrological processes by causing excess soil erosion and changing soil properties. The other opinion is that fires are beneficial to ecosystems; maintaining vegetation structure, preventing bush encroachment, cycling nutrients and allowing for new plant growth. This study focused on the effects of fire regimes on soil properties in order to better understand the role that fire plays in geomorphic processes in the upper Tsitsa River catchment. The catchment falls under two land management types- commercial and communal, with the latter being severely degraded. Fire regimes were determined using a combination of Landsat and MODIS remotely sensed data and testing was carried out on soils exposed to different Fire Return Intervals (FRI). It was found that soils that were exposed to a high fire frequency (1-2-year FRI) exhibited a significantly higher degree of water repellency (p< 0.001) and surface hardness (p< 0.001) than soils that were exposed to a low fire frequency (3-4 year FRI), which indicates increased erosion potential. However, whilst a higher fire frequency resulted in altered soil characteristics, it contributed to landscape degradation as suggested in the literature, and soils are able to return to their previous state in over a short period of time. Further investigation into factors affecting fire regimes found that geology influenced vegetation type, resulting in differences in biomass in the two land management areas. The commercially managed land supported a high biomass, which resulted in a more natural fire regime with frequent fires, whilst the communally managed land supported less biomass. Smaller fuel loads and increased landscape fragmentation through overgrazing and road networks resulted in an altered fire regime with less frequent fires. Although the communally managed land has an altered fire regime, this research suggests that fires are not influencing the severe degradation present in these areas, and this is rather a function of geology and mismanagement of land. Whilst fire and grazing management plans can be implemented to alter the modified fire regime in the communal areas back to its natural state, this would take a long time and an increase in fires would pose a threat to surrounding communities. Overall the fire regimes in the upper Tsitsa River catchment are being altered by human influence and land management type, and whilst fire frequency is negatively altering soil properties, these soils can return to their natural state. The severe land degradation present in the communally managed areas are not a function of fire frequency and rather of geology and land management.
- Full Text:
- Date Issued: 2020
- Authors: Snyman, Gareth
- Date: 2020
- Subjects: Prescribed burning -- Environmental aspects -- South Africa , Fire ecology -- South Africa , Tsitsa River catchment (South Africa) , Soil erosion -- South Africa , Grasslands -- Management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145256 , vital:38422
- Description: South African grasslands are rich in flora and fauna and are a dominant vegetation cover in many of the water catchment areas, while providing a multitude of services to local communities and the environment. Fires have been the primary tool used to manage grasslands for livestock production for many years. However, there is debate about how they impact and alter landscapes and there are two schools of thought throughout literature. One argument is that fires are detrimental to landscapes; altering hydrological processes by causing excess soil erosion and changing soil properties. The other opinion is that fires are beneficial to ecosystems; maintaining vegetation structure, preventing bush encroachment, cycling nutrients and allowing for new plant growth. This study focused on the effects of fire regimes on soil properties in order to better understand the role that fire plays in geomorphic processes in the upper Tsitsa River catchment. The catchment falls under two land management types- commercial and communal, with the latter being severely degraded. Fire regimes were determined using a combination of Landsat and MODIS remotely sensed data and testing was carried out on soils exposed to different Fire Return Intervals (FRI). It was found that soils that were exposed to a high fire frequency (1-2-year FRI) exhibited a significantly higher degree of water repellency (p< 0.001) and surface hardness (p< 0.001) than soils that were exposed to a low fire frequency (3-4 year FRI), which indicates increased erosion potential. However, whilst a higher fire frequency resulted in altered soil characteristics, it contributed to landscape degradation as suggested in the literature, and soils are able to return to their previous state in over a short period of time. Further investigation into factors affecting fire regimes found that geology influenced vegetation type, resulting in differences in biomass in the two land management areas. The commercially managed land supported a high biomass, which resulted in a more natural fire regime with frequent fires, whilst the communally managed land supported less biomass. Smaller fuel loads and increased landscape fragmentation through overgrazing and road networks resulted in an altered fire regime with less frequent fires. Although the communally managed land has an altered fire regime, this research suggests that fires are not influencing the severe degradation present in these areas, and this is rather a function of geology and mismanagement of land. Whilst fire and grazing management plans can be implemented to alter the modified fire regime in the communal areas back to its natural state, this would take a long time and an increase in fires would pose a threat to surrounding communities. Overall the fire regimes in the upper Tsitsa River catchment are being altered by human influence and land management type, and whilst fire frequency is negatively altering soil properties, these soils can return to their natural state. The severe land degradation present in the communally managed areas are not a function of fire frequency and rather of geology and land management.
- Full Text:
- Date Issued: 2020
An investigation into the readiness of open source software to build a Telco Cloud for virtualising network functions
- Authors: Chindeka, Tapiwa C
- Date: 2020
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/124320 , vital:35593
- Description: Cloud computing offers new mechanisms that change the way networks can be created and managed. The increased demand for multimedia and Internet of Things (IoT) services using the Internet Protocol is also fueling the need to look more into a networking approach that is less reliant on physical hardware components and allows new networks and network components to be created on-demand. Network Function Virtualisation (NFV) is a networking paradigm that decouples network functions from the hardware on which they run on. This offers new approaches to telecommunication providers who are looking to new ways of improving Quality of Service (QoS) in cost effective ways. Cloud technologies have given way to more specialised cloud environments such as the telco cloud. The telco cloud is a cloud environment where telecommunication services are hosted utilising NFV techniques. As the use of telecommunication standards moves towards 5G, network services will be provided in a virtualised manner in order to keep up with the demand. Open source software is a driver for innovation as it is has a collaborative culture to support it. This research investigates the readiness of open source tools to build a telco cloud that supports functions such as autoscaling and fault tolerance. Currently available open source software was explored for the different aspects involved in building a cloud from the ground up. The ETSI NFV MANO framework is also discussed as it is a widely used guiding standard for implementing NFV. Guided by the ETSI NFV MANO framework, open source software was used in an experiment to build a resilient cloud environment in which a virtualised IP Multimedia Subsystem (vIMS) network was deployed. Through this experimentation, it is evident that open source tools are mature enough to build the cloud environment and its ETSI NFV MANO compliant orchestration. However, features such as autoscaling and fault tolerance are still fairly immature and experimental.
- Full Text:
- Date Issued: 2020
- Authors: Chindeka, Tapiwa C
- Date: 2020
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/124320 , vital:35593
- Description: Cloud computing offers new mechanisms that change the way networks can be created and managed. The increased demand for multimedia and Internet of Things (IoT) services using the Internet Protocol is also fueling the need to look more into a networking approach that is less reliant on physical hardware components and allows new networks and network components to be created on-demand. Network Function Virtualisation (NFV) is a networking paradigm that decouples network functions from the hardware on which they run on. This offers new approaches to telecommunication providers who are looking to new ways of improving Quality of Service (QoS) in cost effective ways. Cloud technologies have given way to more specialised cloud environments such as the telco cloud. The telco cloud is a cloud environment where telecommunication services are hosted utilising NFV techniques. As the use of telecommunication standards moves towards 5G, network services will be provided in a virtualised manner in order to keep up with the demand. Open source software is a driver for innovation as it is has a collaborative culture to support it. This research investigates the readiness of open source tools to build a telco cloud that supports functions such as autoscaling and fault tolerance. Currently available open source software was explored for the different aspects involved in building a cloud from the ground up. The ETSI NFV MANO framework is also discussed as it is a widely used guiding standard for implementing NFV. Guided by the ETSI NFV MANO framework, open source software was used in an experiment to build a resilient cloud environment in which a virtualised IP Multimedia Subsystem (vIMS) network was deployed. Through this experimentation, it is evident that open source tools are mature enough to build the cloud environment and its ETSI NFV MANO compliant orchestration. However, features such as autoscaling and fault tolerance are still fairly immature and experimental.
- Full Text:
- Date Issued: 2020
An investigation of the morphological and electrochemical properties of anode titanate materials used in li-ion batteries
- Authors: Gelant, Charmaine
- Date: 2020
- Subjects: Electrodes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48346 , vital:40851
- Description: The chemistry involved in the synthesis of lithium titanium oxide (Li4Ti5O12) for lithium ion battery applications is critical for understanding and optimizing the most cost-efficient manufacturing route. This study investigates the sol-gel synthesis technique of Li4Ti5O12 using triethanolamine (TEOA) as complexing agent by means of in-situ Powder X-ray Diffraction (PXRD). The influence of doping with various metals such as Al3+, Mg2+ , Co3+ and Ni2+ that were made as precursors was considered for comparison purposes due to literature showing improved electrochemical performance using the molecular formula of Li4Ti4.95M0.05O12. The in-situ PXRD technique was used to identify the phase changes that occurred in the thermal synthesis process from the sol-gel precursors to the final crystalline oxides. The materials’ decomposition mechanisms were characterized by thermal gravimetric analysis (TGA) as the precursors were gradually heated to obtain the final oxides. BET surface area analysis and scanning electron microscopy (SEM) were used in order to obtain a morphological understanding of the materials during the synthetic route at specific temperature regions. The in-situ studies have shown that the precursor materials are amorphous at room temperature to about 550 °C, after which the spinel and anatase formed, with relatively small crystallites and a large surface area. The study also showed that a crystalline intermediate phase formed at around 150-200 °C, which then disappeared above 250 °C and was speculated to be a titanium acid (H2Ti2O5.H2O). Upon further heating above 250 °C, the anatase phase converted to the high temperature stable TiO2 phase, rutile, also with an increased formation of the expected LTO spinel phase around 850 °C. Keeping the material at 850 °C, isothermally, did show further conversion of the rutile into the desired spinel phase Li4Ti5O12 (LTO) with an increase in the crystallite size and a decrease in surface area. SEM analysis of the material at 850 °C did show some extensive sintering of the particles with some samples indicating the presence of an additional β-Li2TiO3 phase that formed at the high temperatures. Upon cooling, the βLi2TiO3 phase showed a distinctive powder diffraction pattern besides the typical spinel II LTO phase. The study showed that in comparison to the oxide formed at 850 °C, a mixed phase material of the spinel LTO, anatase and rutile could be achieved at temperatures close to 650 °C with very small crystallites and a relatively large surface area that showed desirable electrochemical properties. Suitable Li-ion coin cells were built with the undoped spinel and doped materials that were isothermally made at 650 °C and 850 °C, whereby their electrochemical properties were tested in the form of cell capacity, electrochemical impedance spectroscopy (EIS) and differential capacity (dQ/dV) studies. The cells made with the materials at 850 °C provided reasonable capacity where the dQ/dV plots did show a single step redox reaction at around 1.5V vs Li/Li+ . These were compared to cells made with commercially available LTO and highlighted the importance of high surface area and small particle size of the active material in order to achieve acceptable electrochemical performances. The cells with the materials made at 650 °C showed to have good capacity upon the first discharge with a number of irreversible phase transitions that were subsequently not observed upon recharging. The dQ/dV graphs showed that the phase transitions were unique to the mixed phase composition of the material made at low temperatures and the cells made with the doped spinel materials were on average better performing than the undoped LTO material. Subsequent grinding steps of the active material made at 850 °C improved the capacity performance of the cells but were still lower when compared to the commercially available material. Hence, significantly longer grinding and processing time would be required to achieve battery active materials that are acceptable for commercial use. This study highlights the importance of understanding the phase transitions that occur during the synthesis route of making battery active material, where doping with different elements and using lower temperatures during synthesis could lead to electroactive materials that do not require additional excessive processing steps such as grinding.
- Full Text:
- Date Issued: 2020
- Authors: Gelant, Charmaine
- Date: 2020
- Subjects: Electrodes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/48346 , vital:40851
- Description: The chemistry involved in the synthesis of lithium titanium oxide (Li4Ti5O12) for lithium ion battery applications is critical for understanding and optimizing the most cost-efficient manufacturing route. This study investigates the sol-gel synthesis technique of Li4Ti5O12 using triethanolamine (TEOA) as complexing agent by means of in-situ Powder X-ray Diffraction (PXRD). The influence of doping with various metals such as Al3+, Mg2+ , Co3+ and Ni2+ that were made as precursors was considered for comparison purposes due to literature showing improved electrochemical performance using the molecular formula of Li4Ti4.95M0.05O12. The in-situ PXRD technique was used to identify the phase changes that occurred in the thermal synthesis process from the sol-gel precursors to the final crystalline oxides. The materials’ decomposition mechanisms were characterized by thermal gravimetric analysis (TGA) as the precursors were gradually heated to obtain the final oxides. BET surface area analysis and scanning electron microscopy (SEM) were used in order to obtain a morphological understanding of the materials during the synthetic route at specific temperature regions. The in-situ studies have shown that the precursor materials are amorphous at room temperature to about 550 °C, after which the spinel and anatase formed, with relatively small crystallites and a large surface area. The study also showed that a crystalline intermediate phase formed at around 150-200 °C, which then disappeared above 250 °C and was speculated to be a titanium acid (H2Ti2O5.H2O). Upon further heating above 250 °C, the anatase phase converted to the high temperature stable TiO2 phase, rutile, also with an increased formation of the expected LTO spinel phase around 850 °C. Keeping the material at 850 °C, isothermally, did show further conversion of the rutile into the desired spinel phase Li4Ti5O12 (LTO) with an increase in the crystallite size and a decrease in surface area. SEM analysis of the material at 850 °C did show some extensive sintering of the particles with some samples indicating the presence of an additional β-Li2TiO3 phase that formed at the high temperatures. Upon cooling, the βLi2TiO3 phase showed a distinctive powder diffraction pattern besides the typical spinel II LTO phase. The study showed that in comparison to the oxide formed at 850 °C, a mixed phase material of the spinel LTO, anatase and rutile could be achieved at temperatures close to 650 °C with very small crystallites and a relatively large surface area that showed desirable electrochemical properties. Suitable Li-ion coin cells were built with the undoped spinel and doped materials that were isothermally made at 650 °C and 850 °C, whereby their electrochemical properties were tested in the form of cell capacity, electrochemical impedance spectroscopy (EIS) and differential capacity (dQ/dV) studies. The cells made with the materials at 850 °C provided reasonable capacity where the dQ/dV plots did show a single step redox reaction at around 1.5V vs Li/Li+ . These were compared to cells made with commercially available LTO and highlighted the importance of high surface area and small particle size of the active material in order to achieve acceptable electrochemical performances. The cells with the materials made at 650 °C showed to have good capacity upon the first discharge with a number of irreversible phase transitions that were subsequently not observed upon recharging. The dQ/dV graphs showed that the phase transitions were unique to the mixed phase composition of the material made at low temperatures and the cells made with the doped spinel materials were on average better performing than the undoped LTO material. Subsequent grinding steps of the active material made at 850 °C improved the capacity performance of the cells but were still lower when compared to the commercially available material. Hence, significantly longer grinding and processing time would be required to achieve battery active materials that are acceptable for commercial use. This study highlights the importance of understanding the phase transitions that occur during the synthesis route of making battery active material, where doping with different elements and using lower temperatures during synthesis could lead to electroactive materials that do not require additional excessive processing steps such as grinding.
- Full Text:
- Date Issued: 2020
Analysis of bacterial Mur amide ligase enzymes for the identification of inhibitory compounds by in silico methods
- Chamboko, Chiratidzo Respina
- Authors: Chamboko, Chiratidzo Respina
- Date: 2020
- Subjects: Mur amide ligases , Ligases , Ligand binding (Biochemistry) , Antibacterial agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163430 , vital:41036
- Description: An increased emergence of resistant pathogenic bacterial strains over the years has resulted in many people dying of untreatable infections. This has become one of the most critical global public health problems, as resistant strains are complicating treatment of infectious diseases, increasing human morbidity, mortality, and health care costs. A very limited amount of effective antibiotics is currently available, but the development of novel classes of antibacterial agents is becoming a priority. Mur amide ligases are enzymes that have been identified as potentially good targets for antibiotics, as they are uniquely found in bacteria. They are responsible for the formation of peptide bonds in a growing peptidoglycan structure for bacterial cell walls. The current work presented here focused on characterizing these Mur amide ligase enzymes and obtaining inhibitory compounds that could potentially be of use in drug discovery of antibacterial agents. To do this, multiple sequence alignment, motif analysis and phylogenetic tree constructions were carried out, followed by docking studies and molecular dynamic simulations. Prior to docking, homology modelling of missing residues in the MurF structure (PDB 1GG4) was performed. Characterization results revealed the Mur amide ligase enzymes contained defined conservation in limited regions, that ultimately mapped towards the central domain responsible for ATP binding (presence of a conserved GKT motif). Further analysis of results further unraveled the unique patterns observed within each group of the family of enzymes. As a result of these findings, docking studies were carried out on each Mur amide ligase structure. At most, two ligands were identified to be sufficiently inhibiting each Mur amide ligase. The ligands obtained were SANC00574 and SANC00575 for MurC, SANC00290 and SANC00438 for MurD, SANC00290 and SANC00525 for MurE and SANC00290 and SANC00434 for MurF. The two best ligands identified for each enzyme had docked in the active site of their respective proteins, passed Lipinski’s rule of five and had substantially low binding energies. Molecular dynamic simulations were then performed to analyze the behavior of the proteins and protein-ligand complexes, to confirm the lead compounds as good inhibitors of the Mur amide ligases. In the case of MurC, MurD and MurE complexes, the identified ligands clearly impacted the behavior of the protein, as the ligand bound proteins became more compact and stable, while flexibility decreased. There was however an opposite effect on MurF complexes, that resulted in identified inhibitors being discarded. As a potential next step, in vivo and in vitro experiments can be performed with identified ligands from this research, to further support the information presented.
- Full Text:
- Date Issued: 2020
- Authors: Chamboko, Chiratidzo Respina
- Date: 2020
- Subjects: Mur amide ligases , Ligases , Ligand binding (Biochemistry) , Antibacterial agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/163430 , vital:41036
- Description: An increased emergence of resistant pathogenic bacterial strains over the years has resulted in many people dying of untreatable infections. This has become one of the most critical global public health problems, as resistant strains are complicating treatment of infectious diseases, increasing human morbidity, mortality, and health care costs. A very limited amount of effective antibiotics is currently available, but the development of novel classes of antibacterial agents is becoming a priority. Mur amide ligases are enzymes that have been identified as potentially good targets for antibiotics, as they are uniquely found in bacteria. They are responsible for the formation of peptide bonds in a growing peptidoglycan structure for bacterial cell walls. The current work presented here focused on characterizing these Mur amide ligase enzymes and obtaining inhibitory compounds that could potentially be of use in drug discovery of antibacterial agents. To do this, multiple sequence alignment, motif analysis and phylogenetic tree constructions were carried out, followed by docking studies and molecular dynamic simulations. Prior to docking, homology modelling of missing residues in the MurF structure (PDB 1GG4) was performed. Characterization results revealed the Mur amide ligase enzymes contained defined conservation in limited regions, that ultimately mapped towards the central domain responsible for ATP binding (presence of a conserved GKT motif). Further analysis of results further unraveled the unique patterns observed within each group of the family of enzymes. As a result of these findings, docking studies were carried out on each Mur amide ligase structure. At most, two ligands were identified to be sufficiently inhibiting each Mur amide ligase. The ligands obtained were SANC00574 and SANC00575 for MurC, SANC00290 and SANC00438 for MurD, SANC00290 and SANC00525 for MurE and SANC00290 and SANC00434 for MurF. The two best ligands identified for each enzyme had docked in the active site of their respective proteins, passed Lipinski’s rule of five and had substantially low binding energies. Molecular dynamic simulations were then performed to analyze the behavior of the proteins and protein-ligand complexes, to confirm the lead compounds as good inhibitors of the Mur amide ligases. In the case of MurC, MurD and MurE complexes, the identified ligands clearly impacted the behavior of the protein, as the ligand bound proteins became more compact and stable, while flexibility decreased. There was however an opposite effect on MurF complexes, that resulted in identified inhibitors being discarded. As a potential next step, in vivo and in vitro experiments can be performed with identified ligands from this research, to further support the information presented.
- Full Text:
- Date Issued: 2020
Analysis of bacterial Mur amide ligase enzymes for the identification of inhibitory compounds by in silico methods
- Chamboko, Chiratidzo Respina
- Authors: Chamboko, Chiratidzo Respina
- Date: 2020
- Subjects: Pathogenic microorganisms -- Analysis , Drug resistance in microorganisms , Microorganisms -- Effect of drugs on , Antibiotics -- Effectiveness , Pathogenic bacteria , Drug tolerance , Enzymes -- Analysis , Peptide antibiotics
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161911 , vital:40690
- Description: An increased emergence of resistant pathogenic bacterial strains over the years has resulted in many people dying of untreatable infections. This has become one of the most critical global public health problems, as resistant strains are complicating treatment of infectious diseases, increasing human morbidity, mortality, and health care costs. A very limited amount of effective antibiotics is currently available, but the development of novel classes of antibacterial agents is becoming a priority. Mur amide ligases are enzymes that have been identified as potentially good targets for antibiotics, as they are uniquely found in bacteria. They are responsible for the formation of peptide bonds in a growing peptidoglycan structure for bacterial cell walls. The current work presented here focused on characterizing these Mur amide ligase enzymes and obtaining inhibitory compounds that could potentially be of use in drug discovery of antibacterial agents. To do this, multiple sequence alignment, motif analysis and phylogenetic tree constructions were carried out, followed by docking studies and molecular dynamic simulations. Prior to docking, homology modelling of missing residues in the MurF structure (PDB 1GG4) was performed. Characterization results revealed the Mur amide ligase enzymes contained defined conservation in limited regions, that ultimately mapped towards the central domain responsible for ATP binding (presence of a conserved GKT motif). Further analysis of results further unraveled the unique patterns observed within each group of the family of enzymes. As a result of these findings, docking studies were carried out on each Mur amide ligase structure. At most, two ligands were identified to be sufficiently inhibiting each Mur amide ligase. The ligands obtained were SANC00574 and SANC00575 for MurC, SANC00290 and SANC00438 for MurD, SANC00290 and SANC00525 for MurE and SANC00290 and SANC00434 for MurF. The two best ligands identified for each enzyme had docked in the active site of their respective proteins, passed Lipinski’s rule of five and had substantially low binding energies. Molecular dynamic simulations were then performed to analyze the behavior of the proteins and protein-ligand complexes, to confirm the lead compounds as good inhibitors of the Mur amide ligases. In the case of MurC, MurD and MurE complexes, the identified ligands clearly impacted the behavior of the protein, as the ligand bound proteins became more compact and stable, while flexibility decreased. There was however an opposite effect on MurF complexes, that resulted in identified inhibitors being discarded. As a potential next step, in vivo and in vitro experiments can be performed with identified ligands from this research, to further support the information presented.
- Full Text:
- Date Issued: 2020
- Authors: Chamboko, Chiratidzo Respina
- Date: 2020
- Subjects: Pathogenic microorganisms -- Analysis , Drug resistance in microorganisms , Microorganisms -- Effect of drugs on , Antibiotics -- Effectiveness , Pathogenic bacteria , Drug tolerance , Enzymes -- Analysis , Peptide antibiotics
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161911 , vital:40690
- Description: An increased emergence of resistant pathogenic bacterial strains over the years has resulted in many people dying of untreatable infections. This has become one of the most critical global public health problems, as resistant strains are complicating treatment of infectious diseases, increasing human morbidity, mortality, and health care costs. A very limited amount of effective antibiotics is currently available, but the development of novel classes of antibacterial agents is becoming a priority. Mur amide ligases are enzymes that have been identified as potentially good targets for antibiotics, as they are uniquely found in bacteria. They are responsible for the formation of peptide bonds in a growing peptidoglycan structure for bacterial cell walls. The current work presented here focused on characterizing these Mur amide ligase enzymes and obtaining inhibitory compounds that could potentially be of use in drug discovery of antibacterial agents. To do this, multiple sequence alignment, motif analysis and phylogenetic tree constructions were carried out, followed by docking studies and molecular dynamic simulations. Prior to docking, homology modelling of missing residues in the MurF structure (PDB 1GG4) was performed. Characterization results revealed the Mur amide ligase enzymes contained defined conservation in limited regions, that ultimately mapped towards the central domain responsible for ATP binding (presence of a conserved GKT motif). Further analysis of results further unraveled the unique patterns observed within each group of the family of enzymes. As a result of these findings, docking studies were carried out on each Mur amide ligase structure. At most, two ligands were identified to be sufficiently inhibiting each Mur amide ligase. The ligands obtained were SANC00574 and SANC00575 for MurC, SANC00290 and SANC00438 for MurD, SANC00290 and SANC00525 for MurE and SANC00290 and SANC00434 for MurF. The two best ligands identified for each enzyme had docked in the active site of their respective proteins, passed Lipinski’s rule of five and had substantially low binding energies. Molecular dynamic simulations were then performed to analyze the behavior of the proteins and protein-ligand complexes, to confirm the lead compounds as good inhibitors of the Mur amide ligases. In the case of MurC, MurD and MurE complexes, the identified ligands clearly impacted the behavior of the protein, as the ligand bound proteins became more compact and stable, while flexibility decreased. There was however an opposite effect on MurF complexes, that resulted in identified inhibitors being discarded. As a potential next step, in vivo and in vitro experiments can be performed with identified ligands from this research, to further support the information presented.
- Full Text:
- Date Issued: 2020