Intake of salt and sugar in grade five learners at underprivileged schools in Port Elizabeth compared to the intake at underprivileged schools in Johannesburg
- Authors: Straub, Alycia
- Date: 2018
- Subjects: Children -- Nutrition -- South Africa -- Port Elizabeth , Children -- Nutrition -- South Africa -- Johannesburg , Hypertension , Obesity in children
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/33261 , vital:32614
- Description: The literature clearly indicates that excessive amounts of salt and sugar, compared to the recommended amounts, are consumed by young children, leading to the earlier presentation of lifestyle diseases such as obesity, diabetes mellitus type 2 and hypertension (Lichtenstein et al., 2006; Grimes et al., 2013). The problem to address is that there is insufficient information available on the intake of sugar and salt in South African children, and more specifically in the Johannesburg and Port Elizabeth areas; this information is necessary to determine which prevention strategies should be developed. The aim of this study was to determine the current intake of salt and sugar of grade five learners at a sample of quintile three schools in Johannesburg and Port Elizabeth and to investigate whether there was a relationship between the sugar and salt intake and the BMI (kg/m2) and blood pressure (mmHg) of these learners. A baseline exploratory, quantitative, descriptive, cross-sectional study design was used. A non-random, convenient sampling method was used with a sample size of 220 consenting learners of Johannesburg and 350 of Port Elizabeth. A semi-quantitative adapted food frequency questionnaire was used to determine the current intake of salt and sugar in the learners. The data was analysed using the SPSS version 22 programme. Ethical clearance was obtained from the relevant bodies. The results were as follows: no significant differences were found between the frequency of consumption of any of the food items that were chosen to represent salt and sugar intake and blood pressure and BMI within either Johannesburg or Port Elizabeth. Therefore, no associations between salt and sugar intake and blood pressure and BMI were found within either area. When comparing the learners of Johannesburg with those in Port Elizabeth a few significant differences were found; mostly showing a weak association. However, there was a moderate association for sugar in tea/ coffee between the underweight and overweight/obese learners of Johannesburg compared to Port Elizabeth. Preferences, peer influence and food culture are suggested reasons for this significant difference. Recommendations of the study were the South African Food-based Dietary Guidelines “Use salt and foods high in salt sparingly” and “Use food and drinks that contain sugar sparingly and not between meals” should continue to be encouraged.
- Full Text:
- Date Issued: 2018
- Authors: Straub, Alycia
- Date: 2018
- Subjects: Children -- Nutrition -- South Africa -- Port Elizabeth , Children -- Nutrition -- South Africa -- Johannesburg , Hypertension , Obesity in children
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/33261 , vital:32614
- Description: The literature clearly indicates that excessive amounts of salt and sugar, compared to the recommended amounts, are consumed by young children, leading to the earlier presentation of lifestyle diseases such as obesity, diabetes mellitus type 2 and hypertension (Lichtenstein et al., 2006; Grimes et al., 2013). The problem to address is that there is insufficient information available on the intake of sugar and salt in South African children, and more specifically in the Johannesburg and Port Elizabeth areas; this information is necessary to determine which prevention strategies should be developed. The aim of this study was to determine the current intake of salt and sugar of grade five learners at a sample of quintile three schools in Johannesburg and Port Elizabeth and to investigate whether there was a relationship between the sugar and salt intake and the BMI (kg/m2) and blood pressure (mmHg) of these learners. A baseline exploratory, quantitative, descriptive, cross-sectional study design was used. A non-random, convenient sampling method was used with a sample size of 220 consenting learners of Johannesburg and 350 of Port Elizabeth. A semi-quantitative adapted food frequency questionnaire was used to determine the current intake of salt and sugar in the learners. The data was analysed using the SPSS version 22 programme. Ethical clearance was obtained from the relevant bodies. The results were as follows: no significant differences were found between the frequency of consumption of any of the food items that were chosen to represent salt and sugar intake and blood pressure and BMI within either Johannesburg or Port Elizabeth. Therefore, no associations between salt and sugar intake and blood pressure and BMI were found within either area. When comparing the learners of Johannesburg with those in Port Elizabeth a few significant differences were found; mostly showing a weak association. However, there was a moderate association for sugar in tea/ coffee between the underweight and overweight/obese learners of Johannesburg compared to Port Elizabeth. Preferences, peer influence and food culture are suggested reasons for this significant difference. Recommendations of the study were the South African Food-based Dietary Guidelines “Use salt and foods high in salt sparingly” and “Use food and drinks that contain sugar sparingly and not between meals” should continue to be encouraged.
- Full Text:
- Date Issued: 2018
Interactions between three biological control agents of water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae) in South Africa
- Authors: Petela, Nomvume
- Date: 2018
- Subjects: Water hyacinth -- South Africa , Water hyacinth -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Curculionidae , Delphacidae , Miridae , Neochetina eichhorniae Warner , Megamelus scutellaris Berg , Eccritotarsus eichhorniae Henry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60676 , vital:27814
- Description: Water hyacinth, Eichhomia crassipes (Mart.) Solms (Pontederiaceae) is a free-floating perennial weed that is regarded as the worst aquatic weed in the world because of its negative impacts on aquatic ecosystems. It is native to the Amazon Basin of South America, but since the late 1800s has spread throughout the world. The first record of the weed in South Africa was noted in 1908 on the Cape Flats and in KwaZulu-Natal, but it is now dispersed throughout the country. Mechanical and chemical control methods have been used against the weed, but biological control is considered the most cost-effective, sustainable and environmentally friendly intervention. Currently, nine biological control agents have been released against water hyacinth in South Africa, and Neochetina eichhorniae Warner (Coleoptera: Curculionidae) is used most widely to control it. However, in some sites, water hyacinth mats have still not been brought under control because of eutrophic waters and cool temperatures. It was therefore necessary to release new biological control agents to complement the impact of N. eichhorniae. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released in 2013, but little is known about how it interacts with other agents already present in South Africa. It is likely to compete with the established biological control agent, Eccritotarsus eichhorniae Henry (Heteroptera: Miridae), because they are both sap suckers. On the other hand, N. eichhorniae is the most widespread and thus the most important biological control agent for water hyacinth. The aim of this study, then, was to determine the interactions between the two sap-sucking agents in South Africa that presumably occupy similar niches on the plant, and the interaction between M. scutellerais and N. eichhorniae, the most widely distributed and abundant agent in South Africa. Three experiments were conducted at the Waainek Research Facility at Rhodes University, Grahamstown, Eastern Cape, South Africa. Plants were grown for two weeks and insect species were inoculated singly or in combination. Water hyacinth, plant growth parameters and insect parameters were measured every 14 days for a period of 12 weeks. The results of the study showed that feeding by either E. eichhorniae or M. scutellaris had no effect on the feeding of the other agent. Both agents reduced all the measured plant growth parameters equally, either singly or in combination (i.e. E. eichhorniae or M. scutellaris alone or together). The interaction between the two agents appears neutral and agents are likely to complement each other in the field. Prior feeding by E. eichhorniae or M. scutellaris on water hyacinth did not affect the subsequent feeding by either agent. Megamelus scutellaris prefers healthy fresh water hyacinth plants. In addition, planthoppers performed best in combination with the weevil, especially on plants with new weevil feeding scars. The results of the study showed that M. scutellaris is compatible with other biological control agents of water hyacinth that are already established in South Africa. Therefore, the introduction of M. scutellaris may enhance the biological control of water hyacinth in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Petela, Nomvume
- Date: 2018
- Subjects: Water hyacinth -- South Africa , Water hyacinth -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Curculionidae , Delphacidae , Miridae , Neochetina eichhorniae Warner , Megamelus scutellaris Berg , Eccritotarsus eichhorniae Henry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60676 , vital:27814
- Description: Water hyacinth, Eichhomia crassipes (Mart.) Solms (Pontederiaceae) is a free-floating perennial weed that is regarded as the worst aquatic weed in the world because of its negative impacts on aquatic ecosystems. It is native to the Amazon Basin of South America, but since the late 1800s has spread throughout the world. The first record of the weed in South Africa was noted in 1908 on the Cape Flats and in KwaZulu-Natal, but it is now dispersed throughout the country. Mechanical and chemical control methods have been used against the weed, but biological control is considered the most cost-effective, sustainable and environmentally friendly intervention. Currently, nine biological control agents have been released against water hyacinth in South Africa, and Neochetina eichhorniae Warner (Coleoptera: Curculionidae) is used most widely to control it. However, in some sites, water hyacinth mats have still not been brought under control because of eutrophic waters and cool temperatures. It was therefore necessary to release new biological control agents to complement the impact of N. eichhorniae. Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released in 2013, but little is known about how it interacts with other agents already present in South Africa. It is likely to compete with the established biological control agent, Eccritotarsus eichhorniae Henry (Heteroptera: Miridae), because they are both sap suckers. On the other hand, N. eichhorniae is the most widespread and thus the most important biological control agent for water hyacinth. The aim of this study, then, was to determine the interactions between the two sap-sucking agents in South Africa that presumably occupy similar niches on the plant, and the interaction between M. scutellerais and N. eichhorniae, the most widely distributed and abundant agent in South Africa. Three experiments were conducted at the Waainek Research Facility at Rhodes University, Grahamstown, Eastern Cape, South Africa. Plants were grown for two weeks and insect species were inoculated singly or in combination. Water hyacinth, plant growth parameters and insect parameters were measured every 14 days for a period of 12 weeks. The results of the study showed that feeding by either E. eichhorniae or M. scutellaris had no effect on the feeding of the other agent. Both agents reduced all the measured plant growth parameters equally, either singly or in combination (i.e. E. eichhorniae or M. scutellaris alone or together). The interaction between the two agents appears neutral and agents are likely to complement each other in the field. Prior feeding by E. eichhorniae or M. scutellaris on water hyacinth did not affect the subsequent feeding by either agent. Megamelus scutellaris prefers healthy fresh water hyacinth plants. In addition, planthoppers performed best in combination with the weevil, especially on plants with new weevil feeding scars. The results of the study showed that M. scutellaris is compatible with other biological control agents of water hyacinth that are already established in South Africa. Therefore, the introduction of M. scutellaris may enhance the biological control of water hyacinth in South Africa.
- Full Text:
- Date Issued: 2018
Investigating long-term host-parasite dynamics in odontocetes in Southern Africa
- Authors: Adams, Inge Alison
- Date: 2018
- Subjects: Biological invasions -- Environmental aspects , Cetacea -- Indian Ocean , Ecological disturbances
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23437 , vital:30543
- Description: Cetaceans are a very diverse family and globally, various aspects about their biology have been studied, including infection by parasites. Twenty-five dolphin species can be found in the South African subregion and very little information is available detailing which parasites are infecting them. Parasite samples have been collected opportunistically since the 1970’s from dolphins incidentally caught in shark nets off the KwaZulu-Natal coastline as well as from dolphins stranded along the Eastern Cape coastline. These samples have been stored in the Graham Ross Marine Mammal Collection at the Port Elizabeth Museum and samples belonging to eight odontocete species have been used in the present analysis. These eight species are: the Indian Ocean Humpback Dolphin (Sousa plumbea), the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus), the Long-beaked Common Dolphin (Delphinus capensis), the Risso’s Dolphin (Grampus griseus), the Pantropical Spotted Dolphin (Stenella attenuata), the Striped Dolphin (Stenella coeruleoalba), the Pygmy Sperm Whale (Kogia breviceps) and the Dwarf Sperm Whale (Kogia breviceps). This study aims to investigate which parasites are infecting odontocetes in Southern Africa. Secondly, this study aims to investigate whether any trends in infection exist between sexes, age groups, cause of death and over time. Eighteen parasite species were found to infect odontocetes in Southern Africa. Two could only be identified to family level, seven to genus level and eight to species level. Only one parasite, a trematode, could not be identified and several parasite species were new host records for the subregion. Results showed that the prevalence of parasitic infection has increased over the last four decades, prompting questions regarding the health of our oceans. This study is the first to comprehensively investigate which parasite species are found in these eight odontocete species in Southern Africa. This baseline data will contribute greatly to other types of research involving parasites and provides us with information regarding the health of our ocean.
- Full Text:
- Date Issued: 2018
- Authors: Adams, Inge Alison
- Date: 2018
- Subjects: Biological invasions -- Environmental aspects , Cetacea -- Indian Ocean , Ecological disturbances
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23437 , vital:30543
- Description: Cetaceans are a very diverse family and globally, various aspects about their biology have been studied, including infection by parasites. Twenty-five dolphin species can be found in the South African subregion and very little information is available detailing which parasites are infecting them. Parasite samples have been collected opportunistically since the 1970’s from dolphins incidentally caught in shark nets off the KwaZulu-Natal coastline as well as from dolphins stranded along the Eastern Cape coastline. These samples have been stored in the Graham Ross Marine Mammal Collection at the Port Elizabeth Museum and samples belonging to eight odontocete species have been used in the present analysis. These eight species are: the Indian Ocean Humpback Dolphin (Sousa plumbea), the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus), the Long-beaked Common Dolphin (Delphinus capensis), the Risso’s Dolphin (Grampus griseus), the Pantropical Spotted Dolphin (Stenella attenuata), the Striped Dolphin (Stenella coeruleoalba), the Pygmy Sperm Whale (Kogia breviceps) and the Dwarf Sperm Whale (Kogia breviceps). This study aims to investigate which parasites are infecting odontocetes in Southern Africa. Secondly, this study aims to investigate whether any trends in infection exist between sexes, age groups, cause of death and over time. Eighteen parasite species were found to infect odontocetes in Southern Africa. Two could only be identified to family level, seven to genus level and eight to species level. Only one parasite, a trematode, could not be identified and several parasite species were new host records for the subregion. Results showed that the prevalence of parasitic infection has increased over the last four decades, prompting questions regarding the health of our oceans. This study is the first to comprehensively investigate which parasite species are found in these eight odontocete species in Southern Africa. This baseline data will contribute greatly to other types of research involving parasites and provides us with information regarding the health of our ocean.
- Full Text:
- Date Issued: 2018
Investigating the viability and performance of a pilot scale Fly Ash/Lime Filter Tower (FLFT) for greywater treatment and the fate of Triclosan post treatment
- Authors: Nondlazi, Sinoyolo
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63704 , vital:28473
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
- Authors: Nondlazi, Sinoyolo
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63704 , vital:28473
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Investigating thermal physiology as a tool to improve the release efficacy of insect biological control agents
- Authors: Griffith, Tamzin Camilla
- Date: 2018
- Subjects: Aquatic weeds -- Biological control , Water hyacinth -- Biological control , Insects -- Physiology , Miridae -- Effect of low temperatures on , Cold adaptation , Insects as biological pest control agents , Eccritotarsus catarinensis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63301 , vital:28391
- Description: Biological control is commonly used for the control of invasive aquatic weeds, which often involves the release of multiple host-specific agents. Releasing multiple agents has inherent safety concerns as the introduction of each new agent is associated with risks, but is often required to improve control where establishment is limited. Climatic incompatibility between the agent’s thermal physiology and its introduced range often causes agents to fail to establish. However, it has been suggested that the thermal physiology of insects is plastic. Therefore, the potential to manipulate their thermal physiologies before releasing them into the field needs to be explored; reducing the need to release additional agents, thereby ensuring the safety of biological control. This thesis therefore aimed to firstly, determine whether season and locality influenced the thermal physiology of two field populations of a water hyacinth (Eichhornia crassipes) control agent, the mirid Eccritotarsus catarinensis; one collected from the hottest establishment site, and one collected from the coldest establishment site in South Africa. Their thermal physiology was significantly influenced by season and not by the sites’ climate, suggesting their thermal physiology is plastic under field conditions. Secondly, the classical method of determining the lower critical thermal limit (CTmin), and a new respirometry method of determining this limit, compared the thermal physiology of two Eccritotarsus species reared in quarantine. Eccritotarsus catarinensis was significantly more cold tolerant than the more recently released Eccritotarsus eichhorniae, despite similar maintenance conditions, and as such, was used to establish whether cold hardening under laboratory conditions was possible. Successfully cold hardened E. catarinensis had a significantly lower CTmin compared to the field cold acclimated population, suggesting that cold hardening of agents could be conducted before release to improve their cold tolerance and increase their chances of establishment, allowing for further adaptation to colder climates in the field to occur. Increasing establishment of the most effective agents will decrease the number of agents needed in a biological control programme, thus encouraging a more parsimonious approach to biological control.
- Full Text:
- Date Issued: 2018
- Authors: Griffith, Tamzin Camilla
- Date: 2018
- Subjects: Aquatic weeds -- Biological control , Water hyacinth -- Biological control , Insects -- Physiology , Miridae -- Effect of low temperatures on , Cold adaptation , Insects as biological pest control agents , Eccritotarsus catarinensis
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63301 , vital:28391
- Description: Biological control is commonly used for the control of invasive aquatic weeds, which often involves the release of multiple host-specific agents. Releasing multiple agents has inherent safety concerns as the introduction of each new agent is associated with risks, but is often required to improve control where establishment is limited. Climatic incompatibility between the agent’s thermal physiology and its introduced range often causes agents to fail to establish. However, it has been suggested that the thermal physiology of insects is plastic. Therefore, the potential to manipulate their thermal physiologies before releasing them into the field needs to be explored; reducing the need to release additional agents, thereby ensuring the safety of biological control. This thesis therefore aimed to firstly, determine whether season and locality influenced the thermal physiology of two field populations of a water hyacinth (Eichhornia crassipes) control agent, the mirid Eccritotarsus catarinensis; one collected from the hottest establishment site, and one collected from the coldest establishment site in South Africa. Their thermal physiology was significantly influenced by season and not by the sites’ climate, suggesting their thermal physiology is plastic under field conditions. Secondly, the classical method of determining the lower critical thermal limit (CTmin), and a new respirometry method of determining this limit, compared the thermal physiology of two Eccritotarsus species reared in quarantine. Eccritotarsus catarinensis was significantly more cold tolerant than the more recently released Eccritotarsus eichhorniae, despite similar maintenance conditions, and as such, was used to establish whether cold hardening under laboratory conditions was possible. Successfully cold hardened E. catarinensis had a significantly lower CTmin compared to the field cold acclimated population, suggesting that cold hardening of agents could be conducted before release to improve their cold tolerance and increase their chances of establishment, allowing for further adaptation to colder climates in the field to occur. Increasing establishment of the most effective agents will decrease the number of agents needed in a biological control programme, thus encouraging a more parsimonious approach to biological control.
- Full Text:
- Date Issued: 2018
Investigation of strategies employed in rural households to improve food security in Raymond Mhlaba Local Municipality : a case of Zihlahleni Location in Middledrift, Eastern Cape Province
- Authors: Gqozo, Odwa
- Date: 2018
- Subjects: Food security -- South Africa -- Eastern Cape Rural development -- South Africa -- Eastern Cape Households -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10758 , vital:35752
- Description: Eastern Cape is one of the provinces experiencing a rapid increase in food prices while household income is increasing at a slower rate. Against this background, the main objective of this study was to investigate strategies used by rural households to improve food security in Raymond Mhlaba Local Municipality formally known as Nkonkobe in the Eastern Cape Province, South Africa. Data were collected from 100 households using a questionnaire as the main instrument by using simple random sampling. Data were analyzed by employing simple descriptive statistics to describe household food security. Results revealed that most (50.3percent) households that were interviewed were male headed and unemployment was high (73.6percent). Moreover, the average age of the interviewed household heads was 59 years. Most (68percent) of the households owned home gardens and had access to arable land which was not being cultivated. Most (87percent) households indicated that lack of capital was the main cause of food security and depended on government grants. Most (100percent) of the interviewed household heads depend mostly on food purchases rather than their own production. The recommendation is that the government should continue fostering its agenda of improving agriculture as a strategy in rural households for curbing food insecurity.
- Full Text:
- Date Issued: 2018
- Authors: Gqozo, Odwa
- Date: 2018
- Subjects: Food security -- South Africa -- Eastern Cape Rural development -- South Africa -- Eastern Cape Households -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10758 , vital:35752
- Description: Eastern Cape is one of the provinces experiencing a rapid increase in food prices while household income is increasing at a slower rate. Against this background, the main objective of this study was to investigate strategies used by rural households to improve food security in Raymond Mhlaba Local Municipality formally known as Nkonkobe in the Eastern Cape Province, South Africa. Data were collected from 100 households using a questionnaire as the main instrument by using simple random sampling. Data were analyzed by employing simple descriptive statistics to describe household food security. Results revealed that most (50.3percent) households that were interviewed were male headed and unemployment was high (73.6percent). Moreover, the average age of the interviewed household heads was 59 years. Most (68percent) of the households owned home gardens and had access to arable land which was not being cultivated. Most (87percent) households indicated that lack of capital was the main cause of food security and depended on government grants. Most (100percent) of the interviewed household heads depend mostly on food purchases rather than their own production. The recommendation is that the government should continue fostering its agenda of improving agriculture as a strategy in rural households for curbing food insecurity.
- Full Text:
- Date Issued: 2018
Investigation of the subsurface geology using time domain, magnetic and electrical resistivity geophysical techniques in the Karoo basin at Beaufort west, Western Cape Province, South Africa
- Authors: Ntunja, Asanda
- Date: 2018
- Subjects: Geology Geophysics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14659 , vital:40034
- Description: Beaufort West lies in the Central Karoo Basin and is specifically situated in the Poortjie Member of the Teekloof Formation in the Beaufort Group. The Teekloof Formation was deposited in a floodplain environment and it consists of alternating bluish grey mudstone and very fine to medium grained sandstone. The sediments of the Karoo Basin were intruded by numerous dolerite sills and dykes during a period of extensive magmatic activity over the whole South African subcontinent when the break-up of Gondwanda occurred. This led to a continuous jointing of the sedimentary rocks and the jointing resulted in rocks that are prone to weathering. Weathering that occurred in Beaufort West resulted in the formation of alluvium, calcrete, scree and hard pan deposits which overlay most of the ground surface. The joints in rocks paved way for groundwater storage in the sedimentary beds as sediments of the Karoo Basin lack significant primary porosity. Geophysical surveys were done in order to determine a suitable site to locate and drill a deep borehole to the White Hill Formation in order to extract shale gas that is proposed to be present in the area, thereafter determine sites for monitoring boreholes for groundwater and also look for area where potential groundwater might be present. This then requires geophysical investigations of the surface and subsurface geology of the area prior to drilling so as to locate any features such as dolerite intrusions which may hinder the drilling process and locate shallow aquifers, which will tend to be monitored before and during fracking. Five lines of varying lengths from 2-6 km and different orientation were surveyed using geophysical techniques which included the time domain, electrical resistivity as well as the magnetic methods. The geophysical investigations were conducted in order to fulfil the main vii objectives and aims of the study. The techniques were then complemented by XRF, petrography and density analyses. The time domain method reveals that Lines 1 and Line 2 comprises of rocks with low resistivity values of less than 30 Ωm. These two lines were more conductive towards the east and northeast side of the study site and the resistivity tends to increase towards the south and west. Line 4 appeared to be more conductive towards the south-east of the line. Lines 3 and 5 showed high resistivity values with Line 5 being the most resistive suggesting that the underlying strata is consolidated, dry and hard. The resistivity in all the lines surveyed showed an increase with increasing depth. The depth of investigation was approximately up to 150 m. The electrical resistivity results were only obtained from Line 1 and Line 2. The results, which complement the time domain results, suggest that the two lines indeed comprise of rocks which exhibit low resistivity values. This then implies that the rocks in the vicinity are fractured and the fractures might be field with groundwater and possibly contain some conductive minerals such as sodium oxide (Na2O) as supported by XRF results. This method also reveals that along Line 1, there are individual bodies of high resistivity values. The probing depth of about 78 m was achieved for the electrical resistivity survey. The magnetic data indicate that the magnetic intensity does not vary much across lines 3, 4 and 5 and there is not much change in lithology with depth and lateral extent. The area covered by Lines 1 and 2, and the additional eleven fill in lines has several prominent magnetic highs that are inferred to be due to dolerite intrusions in the sandstones and these bodies may be connected at depth. One of these anomalies which trends east-west direction partially coincides with a mapped dolerite intrusion. Some areas with sandstones also exhibit high viii magnetism which is due to about 3.3% content of Fe2O3 present in the sandstones as seen from XRF. This is probably resulted from weathering of magnetite in dolerite intrusions. Petrography results obtained from samples collected in the field reveal that there is an abundance of quartz in sandstones and siltstones. Quartz arenite also contained about 50% of feldspar, containing both plagioclase and K-feldspar. The sandstones of the Teekloof Formation (Beaufort West) have undergone calcite replacement where the calcite matrix replaced most or all of the clay matrix between the mineral grains. The fractures in rocks were seen and it was inferred that they are due to the present cleavages in feldspar and weathering of feldspar in sandstones. Through X-ray Fluorescence (XRF) analysis, it was revealed that the rocks contained a high percentage of Na2O. XRF also showed that these rocks were under low chemical weathering which led to the formation of new minerals in rock as other minerals such as feldspar weather away. This resulted in quartz being the most dominant mineral present as it is not prone to chemical weathering and thus the rocks were proven to be chemically matured. Thirty one rock samples were collected from the field in order to determine the density and porosity measurements. The fine to medium grained grey sandstones show an average density of 2.597 g/cm3 and a porosity of 1.4 %. The brownish grey sandstone have an average density of 2.546 g/cm3 and porosity of 2.9 % and the brown sandstones exhibit an average of 2.584 g/cm3 and a porosity 1.46 %. Dolerite has an average density of 2.970 g/cm3 and porosity of 0.5 % and siltstones have a density of 2.595 g/cm3 and porosity of 1.38 %. The brownish grey sandstones have the highest porosity and the grey sandstone and siltstone have the least porosity after the dolerite.
- Full Text:
- Date Issued: 2018
- Authors: Ntunja, Asanda
- Date: 2018
- Subjects: Geology Geophysics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14659 , vital:40034
- Description: Beaufort West lies in the Central Karoo Basin and is specifically situated in the Poortjie Member of the Teekloof Formation in the Beaufort Group. The Teekloof Formation was deposited in a floodplain environment and it consists of alternating bluish grey mudstone and very fine to medium grained sandstone. The sediments of the Karoo Basin were intruded by numerous dolerite sills and dykes during a period of extensive magmatic activity over the whole South African subcontinent when the break-up of Gondwanda occurred. This led to a continuous jointing of the sedimentary rocks and the jointing resulted in rocks that are prone to weathering. Weathering that occurred in Beaufort West resulted in the formation of alluvium, calcrete, scree and hard pan deposits which overlay most of the ground surface. The joints in rocks paved way for groundwater storage in the sedimentary beds as sediments of the Karoo Basin lack significant primary porosity. Geophysical surveys were done in order to determine a suitable site to locate and drill a deep borehole to the White Hill Formation in order to extract shale gas that is proposed to be present in the area, thereafter determine sites for monitoring boreholes for groundwater and also look for area where potential groundwater might be present. This then requires geophysical investigations of the surface and subsurface geology of the area prior to drilling so as to locate any features such as dolerite intrusions which may hinder the drilling process and locate shallow aquifers, which will tend to be monitored before and during fracking. Five lines of varying lengths from 2-6 km and different orientation were surveyed using geophysical techniques which included the time domain, electrical resistivity as well as the magnetic methods. The geophysical investigations were conducted in order to fulfil the main vii objectives and aims of the study. The techniques were then complemented by XRF, petrography and density analyses. The time domain method reveals that Lines 1 and Line 2 comprises of rocks with low resistivity values of less than 30 Ωm. These two lines were more conductive towards the east and northeast side of the study site and the resistivity tends to increase towards the south and west. Line 4 appeared to be more conductive towards the south-east of the line. Lines 3 and 5 showed high resistivity values with Line 5 being the most resistive suggesting that the underlying strata is consolidated, dry and hard. The resistivity in all the lines surveyed showed an increase with increasing depth. The depth of investigation was approximately up to 150 m. The electrical resistivity results were only obtained from Line 1 and Line 2. The results, which complement the time domain results, suggest that the two lines indeed comprise of rocks which exhibit low resistivity values. This then implies that the rocks in the vicinity are fractured and the fractures might be field with groundwater and possibly contain some conductive minerals such as sodium oxide (Na2O) as supported by XRF results. This method also reveals that along Line 1, there are individual bodies of high resistivity values. The probing depth of about 78 m was achieved for the electrical resistivity survey. The magnetic data indicate that the magnetic intensity does not vary much across lines 3, 4 and 5 and there is not much change in lithology with depth and lateral extent. The area covered by Lines 1 and 2, and the additional eleven fill in lines has several prominent magnetic highs that are inferred to be due to dolerite intrusions in the sandstones and these bodies may be connected at depth. One of these anomalies which trends east-west direction partially coincides with a mapped dolerite intrusion. Some areas with sandstones also exhibit high viii magnetism which is due to about 3.3% content of Fe2O3 present in the sandstones as seen from XRF. This is probably resulted from weathering of magnetite in dolerite intrusions. Petrography results obtained from samples collected in the field reveal that there is an abundance of quartz in sandstones and siltstones. Quartz arenite also contained about 50% of feldspar, containing both plagioclase and K-feldspar. The sandstones of the Teekloof Formation (Beaufort West) have undergone calcite replacement where the calcite matrix replaced most or all of the clay matrix between the mineral grains. The fractures in rocks were seen and it was inferred that they are due to the present cleavages in feldspar and weathering of feldspar in sandstones. Through X-ray Fluorescence (XRF) analysis, it was revealed that the rocks contained a high percentage of Na2O. XRF also showed that these rocks were under low chemical weathering which led to the formation of new minerals in rock as other minerals such as feldspar weather away. This resulted in quartz being the most dominant mineral present as it is not prone to chemical weathering and thus the rocks were proven to be chemically matured. Thirty one rock samples were collected from the field in order to determine the density and porosity measurements. The fine to medium grained grey sandstones show an average density of 2.597 g/cm3 and a porosity of 1.4 %. The brownish grey sandstone have an average density of 2.546 g/cm3 and porosity of 2.9 % and the brown sandstones exhibit an average of 2.584 g/cm3 and a porosity 1.46 %. Dolerite has an average density of 2.970 g/cm3 and porosity of 0.5 % and siltstones have a density of 2.595 g/cm3 and porosity of 1.38 %. The brownish grey sandstones have the highest porosity and the grey sandstone and siltstone have the least porosity after the dolerite.
- Full Text:
- Date Issued: 2018
Isolation and characterization of E. coli and Campylobacter spp. from diarrhoeal samples collected from selected hospitals in Amathole District Municipality, Eastern Cape, South Africa
- Authors: Omolajaiye, Sunday Abraham
- Date: 2018
- Subjects: Escherichia coli infections Campylobacter infections Diarrhea
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6213 , vital:29515
- Description: Approximately 2-4 billion cases of infectious diarrhoea occur every year, with the highest numbers recorded in sub-Saharan Africa. It remains the most common public health issue among children in developing nations. The purpose of this research was to unfold the prevalence of diarrhoeagenic E. coli and Campylobacter pathotypes as well as elucidate their antibiogram characteristics in diarrhoeal stool samples collected in some medical facilities in Eastern Cape Province, South Africa. Two hundred stool samples were collected from both inpatients and outpatients from male and females of all age groups attending selected medical facilities in the study area. Isolation and characterization of both organisms were done using culture based and molecular methods. Antibiotic susceptibility patterns of identified isolates were determined against a panel of 12 antimicrobial agents. One hundred and twenty presumptive E. coli isolates and 42 presumptive isolates of Campylobacter spp. Were isolated. Eighty-two percent (82 percent) of the presumptive E. coli isolates were confirmed as E. coli while 46.3 percent belonged to Campylobacter spp. Pathotyping of the diarrhoeagenic E. coli isolates by Polymerase chain reaction (PCR) showed the following prevalences: DAEC 43 (32 percent), EHEC 18 (17 percent), EIEC 11 (10 percent) and EPEC 18 (17 percent). EAEC and ETEC were not detected, while for Campylobacter spp. 37 (88 percent) were C. jejuni, and C. coli was not detected. A total of 12 (32.4 percent) of the confirmed Campylobacter jejuni isolates were found to possess the fliM gene, 9 (24.3 percent) possessed the flhA gene and only 6 (16.2 percent) harboured the gene flgE2. None were positive for the flaA, flab and flhB genes.The antibiotic resistance patterns observed among the E. coli isolates were high against ampicillin (98.1 percent), chloramphenicol (94.3 percent) and tetracycline (90.6 percent). For Campylobacter spp., resistance observed were: chloramphenicol (91.6 percent), tetracycline (25.2 percent), erythromycin (49.6 percent) and gentamycin (56.4 percent). A lesser resistance against imipenem (35.9 percent) and quinolone (ciprofloxacin) (45.5 percent) were exhibited by the E.coli isolates. 10.8 percent and 20.3 percent of the Campylobacter isolates were resistant to imipenem and ciprofloxacin respectively. The presence of chloramphenicol (CatA1) and tetracycline (tetA) resistance genes were detected in 94 percent and 89 percent of E. coli isolates respectively while 98 percent of Campylobacter spp. Harboured the catA1 resistance gene. It could be deduced from this study that E. coli and Campylobacter spp. are predomiant enteric pathogens as the etiologic agents of diarrhoea in the study community, and that their antimicrobial resistance is high in the study location. The need to develop strategies to prevent infection and control resistant organisms is evident.
- Full Text:
- Date Issued: 2018
- Authors: Omolajaiye, Sunday Abraham
- Date: 2018
- Subjects: Escherichia coli infections Campylobacter infections Diarrhea
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6213 , vital:29515
- Description: Approximately 2-4 billion cases of infectious diarrhoea occur every year, with the highest numbers recorded in sub-Saharan Africa. It remains the most common public health issue among children in developing nations. The purpose of this research was to unfold the prevalence of diarrhoeagenic E. coli and Campylobacter pathotypes as well as elucidate their antibiogram characteristics in diarrhoeal stool samples collected in some medical facilities in Eastern Cape Province, South Africa. Two hundred stool samples were collected from both inpatients and outpatients from male and females of all age groups attending selected medical facilities in the study area. Isolation and characterization of both organisms were done using culture based and molecular methods. Antibiotic susceptibility patterns of identified isolates were determined against a panel of 12 antimicrobial agents. One hundred and twenty presumptive E. coli isolates and 42 presumptive isolates of Campylobacter spp. Were isolated. Eighty-two percent (82 percent) of the presumptive E. coli isolates were confirmed as E. coli while 46.3 percent belonged to Campylobacter spp. Pathotyping of the diarrhoeagenic E. coli isolates by Polymerase chain reaction (PCR) showed the following prevalences: DAEC 43 (32 percent), EHEC 18 (17 percent), EIEC 11 (10 percent) and EPEC 18 (17 percent). EAEC and ETEC were not detected, while for Campylobacter spp. 37 (88 percent) were C. jejuni, and C. coli was not detected. A total of 12 (32.4 percent) of the confirmed Campylobacter jejuni isolates were found to possess the fliM gene, 9 (24.3 percent) possessed the flhA gene and only 6 (16.2 percent) harboured the gene flgE2. None were positive for the flaA, flab and flhB genes.The antibiotic resistance patterns observed among the E. coli isolates were high against ampicillin (98.1 percent), chloramphenicol (94.3 percent) and tetracycline (90.6 percent). For Campylobacter spp., resistance observed were: chloramphenicol (91.6 percent), tetracycline (25.2 percent), erythromycin (49.6 percent) and gentamycin (56.4 percent). A lesser resistance against imipenem (35.9 percent) and quinolone (ciprofloxacin) (45.5 percent) were exhibited by the E.coli isolates. 10.8 percent and 20.3 percent of the Campylobacter isolates were resistant to imipenem and ciprofloxacin respectively. The presence of chloramphenicol (CatA1) and tetracycline (tetA) resistance genes were detected in 94 percent and 89 percent of E. coli isolates respectively while 98 percent of Campylobacter spp. Harboured the catA1 resistance gene. It could be deduced from this study that E. coli and Campylobacter spp. are predomiant enteric pathogens as the etiologic agents of diarrhoea in the study community, and that their antimicrobial resistance is high in the study location. The need to develop strategies to prevent infection and control resistant organisms is evident.
- Full Text:
- Date Issued: 2018
Isolation, identification and genetic characterisation of a microsporidium isolated from the carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae)
- Authors: Lloyd, Melissa
- Date: 2018
- Subjects: Pyralidae , Pyralidae -- Genetics , Pyralidae -- Phylogeny , Pyralidae -- Pathogens , Cladistic analysis , Transmission electron microscopy , Carob moth (Ectomyelois ceratoniae)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61894 , vital:28075
- Description: Carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) is an economically important pest, yet its biology and pest status on citrus in South Africa was, until recently, poorly understood. A study was initiated to determine the cause of collapse of a laboratory carob moth colony that was established to investigate the biology of carob moth on citrus and to develop integrated management strategies for the pest. An organism was isolated from deceased larvae and was morphologically identified as a microsporidium, based on transmission electron microscopy. Microsporidia are obligate intracellular parasites that have been found to infect almost all eukaryotes. Several Nosema species have been isolated from economically important insect pests, yet little genetic information is available from online databases for identification. Mature spores were recovered and measured using transmission electron microscopy. Spores were ovocylindrical with a wrinkled exospore, and had a length of 2.8 ± 0.02 pm and a width of 1.6 ± 0.04 pm. The identity of the microsporidium was confirmed by PCR amplification, sequencing and analysis of the regions encoding the ribosomal RNA. BLAST analysis of the different rRNA regions amplified showed that the microsporidium shared a 96 - 99 % identity with Nosema sp. M-Pr, Nosema carpocapsae, Nosema oulemae, Nosema sp. CO1, Microsporidium 57864, and Nosema bombi. Phylogenetic analysis of the SSU and LSU rRNA genes showed that the microsporidium clustered with the Nosema / Vairimorpha clade, supported by a bootstrap value of 100. The organisation of the RNA cistron was determined by PCR amplification using the primer set 18f and L1328r to be 5’-SSU-ITS-LSU-IGS-5S-3’, which confirms the placement of the microsporidium within the Nosema / Vairimorpha clade. Because the BLAST results showed a close relationship with Nosema carpocapsae, a microsporidium infecting codling moth, the pathogenicity of the microsporidium was tested against codling moth by inoculating artificial diet with a high spore concentration of 1.1 x 107 spores/ml and a low spore concentration of 1.1 x 104 spores/ml. DNA was extracted from deceased larvae inoculated with the high concentration, and PCR of the SSU rRNA gene and bacterial 16S region was performed. Mortality in the high concentration experiment was significant (p = 0.05), but the cause of infection was determined to be a bacterium, through sequencing and BLAST analysis of the bacterial 16S rDNA. The bacterium shared a 99 % identity with Bacillus cereus. Percentage mortality (p = 0.09), larval mass (p = 0.09) and instar (p = 0.24) did not differ significantly between treatments in the low concentration experiment. DNA was extracted from the larvae and PCR amplification of the SSU rRNA gene was performed to determine whether microsporidia were present. No SSU bands were observed in any of the treatments and percentage mortality was not significant, thus it was determined that no infection occurred. This is the first study to report the genetic characterisation of a microsporidium isolated from carob moth and provides important genetic information for classification of microsporidia within the Nosema / Vairimorpha clade. It is also one of few studies in which the complete rRNA cistron of a species within the Nosema / Vairimorpha clade has been sequenced. The identification of a microsporidium from a laboratory colony of carob moth is important as it provides information about pathogens infecting the carob moth and constraints to carob moth rearing, which is useful for further studies on rearing carob moth and for establishment of a clean colony for research purposes.
- Full Text:
- Date Issued: 2018
- Authors: Lloyd, Melissa
- Date: 2018
- Subjects: Pyralidae , Pyralidae -- Genetics , Pyralidae -- Phylogeny , Pyralidae -- Pathogens , Cladistic analysis , Transmission electron microscopy , Carob moth (Ectomyelois ceratoniae)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61894 , vital:28075
- Description: Carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) is an economically important pest, yet its biology and pest status on citrus in South Africa was, until recently, poorly understood. A study was initiated to determine the cause of collapse of a laboratory carob moth colony that was established to investigate the biology of carob moth on citrus and to develop integrated management strategies for the pest. An organism was isolated from deceased larvae and was morphologically identified as a microsporidium, based on transmission electron microscopy. Microsporidia are obligate intracellular parasites that have been found to infect almost all eukaryotes. Several Nosema species have been isolated from economically important insect pests, yet little genetic information is available from online databases for identification. Mature spores were recovered and measured using transmission electron microscopy. Spores were ovocylindrical with a wrinkled exospore, and had a length of 2.8 ± 0.02 pm and a width of 1.6 ± 0.04 pm. The identity of the microsporidium was confirmed by PCR amplification, sequencing and analysis of the regions encoding the ribosomal RNA. BLAST analysis of the different rRNA regions amplified showed that the microsporidium shared a 96 - 99 % identity with Nosema sp. M-Pr, Nosema carpocapsae, Nosema oulemae, Nosema sp. CO1, Microsporidium 57864, and Nosema bombi. Phylogenetic analysis of the SSU and LSU rRNA genes showed that the microsporidium clustered with the Nosema / Vairimorpha clade, supported by a bootstrap value of 100. The organisation of the RNA cistron was determined by PCR amplification using the primer set 18f and L1328r to be 5’-SSU-ITS-LSU-IGS-5S-3’, which confirms the placement of the microsporidium within the Nosema / Vairimorpha clade. Because the BLAST results showed a close relationship with Nosema carpocapsae, a microsporidium infecting codling moth, the pathogenicity of the microsporidium was tested against codling moth by inoculating artificial diet with a high spore concentration of 1.1 x 107 spores/ml and a low spore concentration of 1.1 x 104 spores/ml. DNA was extracted from deceased larvae inoculated with the high concentration, and PCR of the SSU rRNA gene and bacterial 16S region was performed. Mortality in the high concentration experiment was significant (p = 0.05), but the cause of infection was determined to be a bacterium, through sequencing and BLAST analysis of the bacterial 16S rDNA. The bacterium shared a 99 % identity with Bacillus cereus. Percentage mortality (p = 0.09), larval mass (p = 0.09) and instar (p = 0.24) did not differ significantly between treatments in the low concentration experiment. DNA was extracted from the larvae and PCR amplification of the SSU rRNA gene was performed to determine whether microsporidia were present. No SSU bands were observed in any of the treatments and percentage mortality was not significant, thus it was determined that no infection occurred. This is the first study to report the genetic characterisation of a microsporidium isolated from carob moth and provides important genetic information for classification of microsporidia within the Nosema / Vairimorpha clade. It is also one of few studies in which the complete rRNA cistron of a species within the Nosema / Vairimorpha clade has been sequenced. The identification of a microsporidium from a laboratory colony of carob moth is important as it provides information about pathogens infecting the carob moth and constraints to carob moth rearing, which is useful for further studies on rearing carob moth and for establishment of a clean colony for research purposes.
- Full Text:
- Date Issued: 2018
Labour and external stakeholder management in construction projects
- Authors: Sisilana, Vuyisile
- Date: 2018
- Subjects: Strategic planning , Project management Customer services -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35622 , vital:33764
- Description: In the face of the unemployment crisis in South Africa, organisations involved in infrastructure projects are encouraged to engage local communities, to source any available skills as a form of labour on those projects, as an initiative to alleviate unemployment. This initiative presents numerous challenges in the coordination of resources and activities across organisations. Although this collaborative effort is for combating social problems in our local communities; it has resulted in costing organisations and government millions of Rands because of delays due to work stoppages and cost overruns in construction projects. Stakeholder management theory provides the grounding for this research. Although a framework already exists in project management for stakeholder management, but there is lack of research in the engagement of external stakeholders especially in local community projects and project managers struggle to make the stakeholder management processes relevant to this stakeholder. A qualitative study was undertaken, and the data was collected in the form of semi-structured interviews, to collect the views and perceptions from construction project managers involved in projects affected by local labour work stoppages. This study seeks to find out the real causes and effects of local labour work stoppages and finding efficient ways of resolving this. This research seeks to be a starting point for further research in work stoppages caused by business forums as it was concluded as a major cause during interviews with industry professionals. This research found that disruptions from business forums are one of the causes of work stoppages, which was not found in literature. This research concluded that government intervention is required to resolve this growing challenge. It has been concluded that the project stakeholder management processes are not applied in construction projects by project managers.
- Full Text:
- Date Issued: 2018
- Authors: Sisilana, Vuyisile
- Date: 2018
- Subjects: Strategic planning , Project management Customer services -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35622 , vital:33764
- Description: In the face of the unemployment crisis in South Africa, organisations involved in infrastructure projects are encouraged to engage local communities, to source any available skills as a form of labour on those projects, as an initiative to alleviate unemployment. This initiative presents numerous challenges in the coordination of resources and activities across organisations. Although this collaborative effort is for combating social problems in our local communities; it has resulted in costing organisations and government millions of Rands because of delays due to work stoppages and cost overruns in construction projects. Stakeholder management theory provides the grounding for this research. Although a framework already exists in project management for stakeholder management, but there is lack of research in the engagement of external stakeholders especially in local community projects and project managers struggle to make the stakeholder management processes relevant to this stakeholder. A qualitative study was undertaken, and the data was collected in the form of semi-structured interviews, to collect the views and perceptions from construction project managers involved in projects affected by local labour work stoppages. This study seeks to find out the real causes and effects of local labour work stoppages and finding efficient ways of resolving this. This research seeks to be a starting point for further research in work stoppages caused by business forums as it was concluded as a major cause during interviews with industry professionals. This research found that disruptions from business forums are one of the causes of work stoppages, which was not found in literature. This research concluded that government intervention is required to resolve this growing challenge. It has been concluded that the project stakeholder management processes are not applied in construction projects by project managers.
- Full Text:
- Date Issued: 2018
Lipid pathway regulation in high fat diet induced insulin resistance and prevention by Sutherlandia frutescens
- Nnolum-Orji, Ngozi Francisca
- Authors: Nnolum-Orji, Ngozi Francisca
- Date: 2018
- Subjects: Insulin -- Physiological effect , Fatty acids -- Metabolism Lipids in human nutrition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/33442 , vital:32873
- Description: Excessive dietary fats are key players in the development of insulin resistance (IR). These fatty acids alter the normal lipid metabolic processes, mostly lipolysis and lipogenesis, through hormonal and transcriptional regulation, and in part, through alterations in the gut microbiota composition and their secretion of short-chain fatty acids (SCFAs). In this regard, extensive knowledge on the development (at different time points) of this deregulation of lipid metabolism by high-fat feeding, and the control thereof, is necessary to identify early biomarkers of metabolic diseases such as IR and T2DM, and provide new pharmacological and behavioural lifestyle intervention strategies. In a previous study at NMMU, male Wister rats developed IR within 56 days of chronic intake of a high-fat diet (HFD), while the group that consumed the same HFD supplemented with aqueous extracts of Sutherlandia frutescens (HFD+SF) were protected from IR (Mackenzie, 2009). The present study investigated the role of the gut microbiota via SCFA secretion, and that of the lipid pathways in the observed IR with high-fat feeding, and in the prevention with S. frutescens supplementation. These were done through study of the over-time (days 28, 56 and 86) regulation of gut-derived SCFAs in the liver and plasma samples, as well as the regulation of lipolytic and lipogenic parameters in the liver and adipose tissue samples of these rats. Quantification of SCFAs was carried out using GC-MS technique, while qRT-PCR was used for estimation of the expression levels of genes coding for lipolytic and lipogenic enzymes and transcriptional/regulatory factors. The results obtained showed no role of gut-derived SCFAs as substrates for lipid metabolism in the study rats. Also, gene expression of the lipolytic enzyme (HSL) did not provide evidence of a causative role of adipose lipolysis in the development of observed IR in HFD rats. However, the importance of adipose tissue insulin sensitivity to the maintenance of normal lipolytic rates was indicated in Sutherlandia treated rats. On the other hand, over-time decrease in the gene expression of lipogenic enzymes (ACC and FAS) in the liver and adipose tissues of HFD rats imply that deregulation of lipogenesis contributed to IR in these rats. Conversely, stimulation of lipogenesis in the S. frutescens treated rats prevented the rats from developing IR. Furthermore, gene expression of the transcription factors (liver PPARalpha for lipolysis; and SREBP-1c and PPARgamma for lipogenesis) correlate these observations. Leptin gene expression supports its effect on lipolysis but not lipogenesis, while gene expressions of SCFA receptors correlate FFAR2, but not FFAR3, to lipogenesis and lipolysis.
- Full Text:
- Date Issued: 2018
- Authors: Nnolum-Orji, Ngozi Francisca
- Date: 2018
- Subjects: Insulin -- Physiological effect , Fatty acids -- Metabolism Lipids in human nutrition
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/33442 , vital:32873
- Description: Excessive dietary fats are key players in the development of insulin resistance (IR). These fatty acids alter the normal lipid metabolic processes, mostly lipolysis and lipogenesis, through hormonal and transcriptional regulation, and in part, through alterations in the gut microbiota composition and their secretion of short-chain fatty acids (SCFAs). In this regard, extensive knowledge on the development (at different time points) of this deregulation of lipid metabolism by high-fat feeding, and the control thereof, is necessary to identify early biomarkers of metabolic diseases such as IR and T2DM, and provide new pharmacological and behavioural lifestyle intervention strategies. In a previous study at NMMU, male Wister rats developed IR within 56 days of chronic intake of a high-fat diet (HFD), while the group that consumed the same HFD supplemented with aqueous extracts of Sutherlandia frutescens (HFD+SF) were protected from IR (Mackenzie, 2009). The present study investigated the role of the gut microbiota via SCFA secretion, and that of the lipid pathways in the observed IR with high-fat feeding, and in the prevention with S. frutescens supplementation. These were done through study of the over-time (days 28, 56 and 86) regulation of gut-derived SCFAs in the liver and plasma samples, as well as the regulation of lipolytic and lipogenic parameters in the liver and adipose tissue samples of these rats. Quantification of SCFAs was carried out using GC-MS technique, while qRT-PCR was used for estimation of the expression levels of genes coding for lipolytic and lipogenic enzymes and transcriptional/regulatory factors. The results obtained showed no role of gut-derived SCFAs as substrates for lipid metabolism in the study rats. Also, gene expression of the lipolytic enzyme (HSL) did not provide evidence of a causative role of adipose lipolysis in the development of observed IR in HFD rats. However, the importance of adipose tissue insulin sensitivity to the maintenance of normal lipolytic rates was indicated in Sutherlandia treated rats. On the other hand, over-time decrease in the gene expression of lipogenic enzymes (ACC and FAS) in the liver and adipose tissues of HFD rats imply that deregulation of lipogenesis contributed to IR in these rats. Conversely, stimulation of lipogenesis in the S. frutescens treated rats prevented the rats from developing IR. Furthermore, gene expression of the transcription factors (liver PPARalpha for lipolysis; and SREBP-1c and PPARgamma for lipogenesis) correlate these observations. Leptin gene expression supports its effect on lipolysis but not lipogenesis, while gene expressions of SCFA receptors correlate FFAR2, but not FFAR3, to lipogenesis and lipolysis.
- Full Text:
- Date Issued: 2018
Macroinvertebrate and diatom assemblage responses to pollution, with emphasis on salinity, in the Kat River, Eastern Cape South Africa
- Authors: Mgaba, Ntombekhaya
- Date: 2018
- Subjects: Water -- Pollution -- South Africa -- Kat River , Stream salinity -- South Africa -- Kat River , Sewage disposal plants -- South Africa , Environmental monitoring -- South Africa -- Kat River , Water quality -- South Africa -- Kat River , South African Scoring System version 5 (SASS5) , Macroinvertebrate Response Assessment Index (MIRAI)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63279 , vital:28389
- Description: Salinity has been implicated as one of the major contributors to deteriorating water quality of freshwater ecosystems around the globe. In South Africa, anthropogenic activities such as mining, agriculture, industry and wastewater treatment works (WWTWs) are the major sources of increasing salinity levels of freshwater resources. The main focus of this study was to assess the impact of salinity on water quality of the Kat River using macroinvertebrates and diatoms as bioindicators. Biomonitoring using macroinvertebrates and diatom communities and concurrent sampling of water physicochemical variables were conducted bi-monthly from December 2015 to November 2016.This period covered summer and winter, and the study was conducted at five selected sites (Sites 1, 2, 3, 4 and 5) along the length of the Kat River. For macroinvertebrates biomonitoring, the South African Scoring System version 5 (SASS5) and Macroinvertebrate Response Assessment Index (MIRAI) were applied to collect and analyse data, while the Taylor et al (2006) protocol for collecting and analysing diatom assemblages was modified and used for diatom collection and analysis. Water physicochemical variables, including hydrogen ion concentration (pH), electrical conductivity (EC), dissolved oxygen (DO), temperature, turbidity and stream flow were determined in situ using appropriate multiprobe meter and/or techniques. Nutrients (NO3-N, NO2-N, NH4-N and PO4-P) were analysed in the laboratory using appropriate analytical methods. All data were subjected to appropriate statistical analyses and statistical decisions were made at an alpha value of 0.05. Particularly, multivariate analyses of both macroinvertebrates and diatoms assemblages were conducted using canonical correspondence analysis and Bray-Curtis similarity analysis, while indicator species analysis was used to determine which species is/are more significant with respect to biomonitoring in the Kat River. Biotic diversity indices were also measured and used to discriminate between least and most impacted sites. The Kat River water quality was found to have experienced a varying degree of modification compared to Generic Resources Water Quality Objectives limits. Change in DO, stream flow, EC, nutrients and turbidity exerted the greatest influenced on the macroinvertebrates assemblage structure, with organisms at Sites 4 and 5 (downstream sites) showing more significant negative impact compared to organisms at Sites 1, 2 and 3 (upstream sites). Analysis of the diatom biomonitoring showed more negative impact at Sites 2, 4 and 5 compared to Sites 1 and 3. Fort Beaufort Wastewater Treatment Works and small-scale farming activities, as well as leaking of pipes carrying sewage, were found to be the likely major sources of anthropogenic activities responsible for the observed increased salinity and other pollutants in the Kat River. Overall, this study found macroinvertebrates (identified up to the family level) as good for biomonitoring to assess or predict water quality of the Kat River, while diatoms were found to be most suitable for biomonitoring to assess salinity in the Kat River.
- Full Text:
- Date Issued: 2018
- Authors: Mgaba, Ntombekhaya
- Date: 2018
- Subjects: Water -- Pollution -- South Africa -- Kat River , Stream salinity -- South Africa -- Kat River , Sewage disposal plants -- South Africa , Environmental monitoring -- South Africa -- Kat River , Water quality -- South Africa -- Kat River , South African Scoring System version 5 (SASS5) , Macroinvertebrate Response Assessment Index (MIRAI)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63279 , vital:28389
- Description: Salinity has been implicated as one of the major contributors to deteriorating water quality of freshwater ecosystems around the globe. In South Africa, anthropogenic activities such as mining, agriculture, industry and wastewater treatment works (WWTWs) are the major sources of increasing salinity levels of freshwater resources. The main focus of this study was to assess the impact of salinity on water quality of the Kat River using macroinvertebrates and diatoms as bioindicators. Biomonitoring using macroinvertebrates and diatom communities and concurrent sampling of water physicochemical variables were conducted bi-monthly from December 2015 to November 2016.This period covered summer and winter, and the study was conducted at five selected sites (Sites 1, 2, 3, 4 and 5) along the length of the Kat River. For macroinvertebrates biomonitoring, the South African Scoring System version 5 (SASS5) and Macroinvertebrate Response Assessment Index (MIRAI) were applied to collect and analyse data, while the Taylor et al (2006) protocol for collecting and analysing diatom assemblages was modified and used for diatom collection and analysis. Water physicochemical variables, including hydrogen ion concentration (pH), electrical conductivity (EC), dissolved oxygen (DO), temperature, turbidity and stream flow were determined in situ using appropriate multiprobe meter and/or techniques. Nutrients (NO3-N, NO2-N, NH4-N and PO4-P) were analysed in the laboratory using appropriate analytical methods. All data were subjected to appropriate statistical analyses and statistical decisions were made at an alpha value of 0.05. Particularly, multivariate analyses of both macroinvertebrates and diatoms assemblages were conducted using canonical correspondence analysis and Bray-Curtis similarity analysis, while indicator species analysis was used to determine which species is/are more significant with respect to biomonitoring in the Kat River. Biotic diversity indices were also measured and used to discriminate between least and most impacted sites. The Kat River water quality was found to have experienced a varying degree of modification compared to Generic Resources Water Quality Objectives limits. Change in DO, stream flow, EC, nutrients and turbidity exerted the greatest influenced on the macroinvertebrates assemblage structure, with organisms at Sites 4 and 5 (downstream sites) showing more significant negative impact compared to organisms at Sites 1, 2 and 3 (upstream sites). Analysis of the diatom biomonitoring showed more negative impact at Sites 2, 4 and 5 compared to Sites 1 and 3. Fort Beaufort Wastewater Treatment Works and small-scale farming activities, as well as leaking of pipes carrying sewage, were found to be the likely major sources of anthropogenic activities responsible for the observed increased salinity and other pollutants in the Kat River. Overall, this study found macroinvertebrates (identified up to the family level) as good for biomonitoring to assess or predict water quality of the Kat River, while diatoms were found to be most suitable for biomonitoring to assess salinity in the Kat River.
- Full Text:
- Date Issued: 2018
Manufacturing of continuous flow equipment
- Authors: Strydom, Martin
- Date: 2018
- Subjects: Microfluidics , Nanofluids Micro-reactor
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35818 , vital:33850
- Description: For the work of this thesis a proof of concept microreactor and pump have been designed. Open source technology was used where possible to reduce the manufacturing cost. The pump is a pseudo HPLC/Syringe pump hybrid which adopts designs from both pumping systems. It works by charging two volumes of liquid into the primary chamber while the secondary chamber discharges. When the charge of the primary chamber is complete half of the liquid is pumped into the secondary chamber and the other half gets discharged. This has the benefit of sharing a common drive to reduce cost. The pump did function; however, the 3D printed parts did not have sufficient rigidity to offset mechanical stress, thus flexing occurred. The micro-reactor that was developed, was unique to commercial units. It was not chemically or thermally bonded but clamped with a gasket sealing the channels. This provides the advantage of unblocking inert material in the reactor. The reactor disk that was clamped was a super alloy, namely, Hastelloy C276. The reactor was tested against two commonly used reactors, namely, Chemtrix3227 and Little Things Factory (MS+VS). A simple synthesis of ethyl acetate has been used as a model reaction for comparing. The test reactor did not perform as well as the commercial counterparts, however probable causes have been identified for potential future work. Both the pump and the reactor worked as a proof of concept system, however further development is required for commercialisation.
- Full Text:
- Date Issued: 2018
- Authors: Strydom, Martin
- Date: 2018
- Subjects: Microfluidics , Nanofluids Micro-reactor
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/35818 , vital:33850
- Description: For the work of this thesis a proof of concept microreactor and pump have been designed. Open source technology was used where possible to reduce the manufacturing cost. The pump is a pseudo HPLC/Syringe pump hybrid which adopts designs from both pumping systems. It works by charging two volumes of liquid into the primary chamber while the secondary chamber discharges. When the charge of the primary chamber is complete half of the liquid is pumped into the secondary chamber and the other half gets discharged. This has the benefit of sharing a common drive to reduce cost. The pump did function; however, the 3D printed parts did not have sufficient rigidity to offset mechanical stress, thus flexing occurred. The micro-reactor that was developed, was unique to commercial units. It was not chemically or thermally bonded but clamped with a gasket sealing the channels. This provides the advantage of unblocking inert material in the reactor. The reactor disk that was clamped was a super alloy, namely, Hastelloy C276. The reactor was tested against two commonly used reactors, namely, Chemtrix3227 and Little Things Factory (MS+VS). A simple synthesis of ethyl acetate has been used as a model reaction for comparing. The test reactor did not perform as well as the commercial counterparts, however probable causes have been identified for potential future work. Both the pump and the reactor worked as a proof of concept system, however further development is required for commercialisation.
- Full Text:
- Date Issued: 2018
Metabolic Systems Biology: Uncovering operations of cell and metabolism
- Authors: Marange , Israel Yeukai
- Date: 2018
- Subjects: Systems biology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19120 , vital:39881
- Description: The aim of this work is to analyse the technique for formulating cellular metabolism in living organisms. It also focuses on developing models of cellular metabolic systems. A sequence of biochemical reactions termed metabolic branched pathways that occur inside a cell, are of particular interest.Mathematical modelling is used as a tool to examine and analyse the metabolism of viral dynamics for the ends of this research. Dynamic mathematical models provide an important means with which to investigate the cell cycle control system. The derivation of the ordinary differential equations (ODEs) is useful in describing and analysing the metabolic network structures of branched flux pathways, as well as enzyme-substrate,reciprocal-action networks which control the cell cycle. Different general and specific factors affecting metabolic rate are identified and explained
- Full Text:
- Date Issued: 2018
- Authors: Marange , Israel Yeukai
- Date: 2018
- Subjects: Systems biology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19120 , vital:39881
- Description: The aim of this work is to analyse the technique for formulating cellular metabolism in living organisms. It also focuses on developing models of cellular metabolic systems. A sequence of biochemical reactions termed metabolic branched pathways that occur inside a cell, are of particular interest.Mathematical modelling is used as a tool to examine and analyse the metabolism of viral dynamics for the ends of this research. Dynamic mathematical models provide an important means with which to investigate the cell cycle control system. The derivation of the ordinary differential equations (ODEs) is useful in describing and analysing the metabolic network structures of branched flux pathways, as well as enzyme-substrate,reciprocal-action networks which control the cell cycle. Different general and specific factors affecting metabolic rate are identified and explained
- Full Text:
- Date Issued: 2018
Method development for chemolysis of waste tyres and characterization of the components
- Authors: Tsipa, Phuti Cedric
- Date: 2018
- Subjects: Composite materials , Rubber Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36694 , vital:34044
- Description: Chemolysis method for degradation and extraction of waste tyres for production of oil was developed. This method consist of three different solvent systems; firstly, the selective solvent system capable of extracting the process oil used in the production of tyres. This solvent system follows a phase transfer catalysis reaction, which is a reaction with a solvent consisting of two phases. Second system is a Destructive solvent system, which is capable of breaking down the polymer chains within the rubber matrix. It follows phase transfer catalysis reaction. Lastly, the collecting/wash solvent system, which is capable of collecting the remaining extracts in the residual crumb. Three products where obtained from this method: Liquid (oil), Gas and Solid (char), with the oil plus char being the focus of this study. Characterizations were carried out to obtain the quality of the oil recovered. Various analytical techniques were used to achieve the aims and objectives of this study, this involved Fourier Transform Infra-red spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) spectroscopy, High-resolution Thermogravimetric analysis (Hi-resTM TGA), Gas Chromatography coupled to Mass spectroscopy (GC-MS) and Simulated Distillation D86 (SIMDIST D86). Hydrocarbon compounds and market value acids where identified with reference to standards ran on the GC-MS. Market value acids were quantified to obtain the exact amount present in the extracted oil, the amounts for dodecanoic acid, hexadecanoic acid, heptadecanoic acid and octadecanoic acid were 0.73%, 5.1%, 0.49% and 9.98% respectively. Approximately 15% of this market value acid are present in the extracted oil. Internal GC-MS library and Retention Index (RI) methods with the help of NIST library were also used for compounds identification. A total of 53 compounds were successfully identified. SIMDIST D86 analysis showed that the petroleum fractions present in the total extracted oil were Heavy naphtha 0.73%, Kerosene 3.23%, Distillate fuel oil 6.27%, Light vacuum gas oil 57.93% and Heavy vacuum gas oil 31.83%. Hi-resTM TGA was used to characterize the char recovered for thermal properties. Chemolysis char showed relatively similar thermal stability compared to commercial N115 carbon black. The chemolysis method of oil extraction from waste tyres reported in this thesis shows promise in terms of both the routine of execution, quantification of market value constituents of the oil and chemical details of both the tyre derived oil and char.
- Full Text:
- Date Issued: 2018
- Authors: Tsipa, Phuti Cedric
- Date: 2018
- Subjects: Composite materials , Rubber Chemistry, Organic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36694 , vital:34044
- Description: Chemolysis method for degradation and extraction of waste tyres for production of oil was developed. This method consist of three different solvent systems; firstly, the selective solvent system capable of extracting the process oil used in the production of tyres. This solvent system follows a phase transfer catalysis reaction, which is a reaction with a solvent consisting of two phases. Second system is a Destructive solvent system, which is capable of breaking down the polymer chains within the rubber matrix. It follows phase transfer catalysis reaction. Lastly, the collecting/wash solvent system, which is capable of collecting the remaining extracts in the residual crumb. Three products where obtained from this method: Liquid (oil), Gas and Solid (char), with the oil plus char being the focus of this study. Characterizations were carried out to obtain the quality of the oil recovered. Various analytical techniques were used to achieve the aims and objectives of this study, this involved Fourier Transform Infra-red spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) spectroscopy, High-resolution Thermogravimetric analysis (Hi-resTM TGA), Gas Chromatography coupled to Mass spectroscopy (GC-MS) and Simulated Distillation D86 (SIMDIST D86). Hydrocarbon compounds and market value acids where identified with reference to standards ran on the GC-MS. Market value acids were quantified to obtain the exact amount present in the extracted oil, the amounts for dodecanoic acid, hexadecanoic acid, heptadecanoic acid and octadecanoic acid were 0.73%, 5.1%, 0.49% and 9.98% respectively. Approximately 15% of this market value acid are present in the extracted oil. Internal GC-MS library and Retention Index (RI) methods with the help of NIST library were also used for compounds identification. A total of 53 compounds were successfully identified. SIMDIST D86 analysis showed that the petroleum fractions present in the total extracted oil were Heavy naphtha 0.73%, Kerosene 3.23%, Distillate fuel oil 6.27%, Light vacuum gas oil 57.93% and Heavy vacuum gas oil 31.83%. Hi-resTM TGA was used to characterize the char recovered for thermal properties. Chemolysis char showed relatively similar thermal stability compared to commercial N115 carbon black. The chemolysis method of oil extraction from waste tyres reported in this thesis shows promise in terms of both the routine of execution, quantification of market value constituents of the oil and chemical details of both the tyre derived oil and char.
- Full Text:
- Date Issued: 2018
Microhabitat and biotic structure of stromatolite formations
- Authors: Weston, Ross-Lynne Alida
- Date: 2018
- Subjects: Stromatolites , Microbial mats Sedimentary structures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/17493 , vital:28358
- Description: Stromatolites are among the oldest types of microbial formations. In contrast to their ancient counterparts, many modern marine stromatolites have a coarser internal structure and host a diverse eukaryotic community. Different mesofabric structures are found within stromatolite formations which may provide microhabitat opportunities for organisms. Therefore, the first aim of this study was to investigate how the microalgal (including Bacillariophyta, Chlorophyta and cyanobacteria) community contributes towards the differences observed amongst mesofabric structures in terms of depth profiles and layering at representative stromatolites forming along the Port Elizabeth coastline in South Africa. The second aim was to investigate how the invertebrate community changes between mesofabric types. This was achieved by comparing the proportional abundances of each of the major microalgal classes between the different mesofabric types and depth profiles. Additionally, the invertebrates found within samples collected were identified and counted. These were related to site and environmental characteristics using multivariate modelling. Clear variability in terms of proportional abundance was apparent between microhabitats and with depth. Coarser, more-bioturbated types had a higher bacillariophyte biomass than smoother types. Invertebrate abundance was generally higher in coarser mats. However, one of the finer, well-laminated types had surprisingly more invertebrates than expected, but only in summer. The changes in microalgal and invertebrate community distribution varied seasonally. More microalgae were found in summer and more invertebrates were found in winter. Microalgae distribution was driven by mesofabric features whereas invertebrate distribution was attributed to resource changes. The implications of this study are in terms of the role of microalgae as ecosystem engineers in driving microhabitat differences. The microhabitats provide opportunities for colonisation by invertebrates.
- Full Text:
- Date Issued: 2018
- Authors: Weston, Ross-Lynne Alida
- Date: 2018
- Subjects: Stromatolites , Microbial mats Sedimentary structures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/17493 , vital:28358
- Description: Stromatolites are among the oldest types of microbial formations. In contrast to their ancient counterparts, many modern marine stromatolites have a coarser internal structure and host a diverse eukaryotic community. Different mesofabric structures are found within stromatolite formations which may provide microhabitat opportunities for organisms. Therefore, the first aim of this study was to investigate how the microalgal (including Bacillariophyta, Chlorophyta and cyanobacteria) community contributes towards the differences observed amongst mesofabric structures in terms of depth profiles and layering at representative stromatolites forming along the Port Elizabeth coastline in South Africa. The second aim was to investigate how the invertebrate community changes between mesofabric types. This was achieved by comparing the proportional abundances of each of the major microalgal classes between the different mesofabric types and depth profiles. Additionally, the invertebrates found within samples collected were identified and counted. These were related to site and environmental characteristics using multivariate modelling. Clear variability in terms of proportional abundance was apparent between microhabitats and with depth. Coarser, more-bioturbated types had a higher bacillariophyte biomass than smoother types. Invertebrate abundance was generally higher in coarser mats. However, one of the finer, well-laminated types had surprisingly more invertebrates than expected, but only in summer. The changes in microalgal and invertebrate community distribution varied seasonally. More microalgae were found in summer and more invertebrates were found in winter. Microalgae distribution was driven by mesofabric features whereas invertebrate distribution was attributed to resource changes. The implications of this study are in terms of the role of microalgae as ecosystem engineers in driving microhabitat differences. The microhabitats provide opportunities for colonisation by invertebrates.
- Full Text:
- Date Issued: 2018
Mining, agriculture and wetland ecological infrastructure in the Upper Komati catchment (South Africa): contestations in a complex social-ecological system
- Authors: Keighley, Tia-Kristi
- Date: 2018
- Subjects: Wetland ecology -- Komati River Watershed , Coal mines and mining -- Environmental aspects -- Komati River Watershed , Agriculture -- Environmental aspects -- Komati River Watershed , Acid mine drainage -- Komati River Watershed , Water quality -- Physiological effect -- Komati River Watershed , Wetland conservation -- Komati River Watershed , National Freshwater Ecosystem Priority Areas (NFEPAs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63810 , vital:28491
- Description: Wetlands provide a wide variety of natural benefits (ecosystem services) from the natural environment to human populations, making them key examples of ecological infrastructure. However, the use of wetlands and their associated catchments is often contested by different users, making them nodes of conflict. Thus, there is a range of pressures on many wetlands which can ultimately lead to degradation or destruction. This study investigated the X11B quaternary catchment in the Upper Inkomati basin, Mpumalanga, South Africa. This catchment is characterised by a network of wetlands and streams that provide catchment residents with water. The sub-catchment is heavily used, dominated by the agricultural sector and coal mining. To understand the contestation, a contextual analysis was carried out. Selected wetland conditions and ecosystem services, along with user perceptions and the value of wetland-use, were assessed. Wetlands were observably in a relatively healthy condition. The resilience of wetlands and the efficiency of the ecosystem services they offer, especially in mediating water quality, were clear. The early results indicated a healthy landscape despite multiple-user impact from human activity. The health scores and provision of ecosystem services, along with the identified National Freshwater Ecosystem Priority Areas (NFEPAs) and red-listed fauna and flora, provide a substantial grounding for advocating the conservation of the wetlands of the contested X11B catchment. When water quality measures were added to the wetland health and ecosystem service assessment, low pH levels and high electrical conductivity were recorded. Both measures indicate coal mining impacts, more specifically Acid Mine Drainage (AMD) impacts, since AMD typically has sulphate as the dominant salt ion, and high concentrations of trace elements and metal ions. Concentrations breaching the recommended resource quality objectives (RQOs) of trace elements and ions, found in fertilizers and pesticides, were recorded in most sites, suggesting agricultural impacts on the landscape’s hydrology. Further, these agricultural impacts would add to the compromising effect of the wetlands’ capacity to remove pollutants from the water body. Livestock farming on all sites were also near wetlands which may have limited the vegetation cover of grazed land, so increasing runoff and the volume of water entering wetlands and compromising their ecosystem services. Poor water quality has implications for biophysical processes, which play an important role in the functioning of wetlands, for the benefit of users. Without the water quality measures, ecosystem health and ecosystem service methodology used suggested a healthy catchment. However, simple field water quality measures indicated past and present mining impacts. Therefore, the mandatory use of water chemistry is recommended in the assessment of wetlands in catchments with past and present mining activity taking place. Without this, repercussions would include wetland loss, and a more thorough investigation into the water quality and its effects on the wetland ecosystems is suggested. Further ecological investigation of water chemistry (heavy metals, ions, nutrients and trace elements) and macroinvertebrate assemblages identified links to water chemistry impacts on macroinvertebrate abundance and diversity. Abundance results based on the presence, absence and abundance of macroinvertebrates at the different sites did not reveal any clear patterns associated with different landscape users. Diversity, on the other hand, was related to land-use, where sites with high mining use had lower macroinvertebrate diversity than other sites. Related, concurrent, hydro-pedology research produced a more comprehensive understanding of the impact of mining on hydro-connectivity that clearly indicates mining as the cause of long-term deterioration of functional wetland health in a way that is practically impossible to restore. This study suggests that wetlands provide a strong ecosystem service of intermittent resetting of the wetland sediment adsorptive capacity for toxic metal and other salt ions. The hypothesis arising from the work is that, in the case of another heavy rainfall event, the town of Carolina risks another AMD crisis. As sediments are likely to be accumulating and saturated with toxic metal ions. Further AMD-related changes in acidity will increase the mobilisation of adsorbed ions. Future flooding and flushing of wetlands will therefore once again move toxic metal ions through the system, and possibly re-contaminate the Boesmanspruit dam. The value of the study is in delivering specific evidence on the impacts of mining (and to a lesser extent agriculture) on wetland quality. Overall, this study, combined with additional research, indicates that in the X11B catchment, mining impacts are long-term and more serious than agriculture. In terms of contestation the research indicates that reliance on bio-physical data and knowledge is inadequate in resolving conflict between coal mining and other land- and water-users. The study demonstrates the necessity of insight into the social system and the value of a transdisciplinary approach in addressing land-use conflicts and wetland protection.
- Full Text:
- Date Issued: 2018
- Authors: Keighley, Tia-Kristi
- Date: 2018
- Subjects: Wetland ecology -- Komati River Watershed , Coal mines and mining -- Environmental aspects -- Komati River Watershed , Agriculture -- Environmental aspects -- Komati River Watershed , Acid mine drainage -- Komati River Watershed , Water quality -- Physiological effect -- Komati River Watershed , Wetland conservation -- Komati River Watershed , National Freshwater Ecosystem Priority Areas (NFEPAs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63810 , vital:28491
- Description: Wetlands provide a wide variety of natural benefits (ecosystem services) from the natural environment to human populations, making them key examples of ecological infrastructure. However, the use of wetlands and their associated catchments is often contested by different users, making them nodes of conflict. Thus, there is a range of pressures on many wetlands which can ultimately lead to degradation or destruction. This study investigated the X11B quaternary catchment in the Upper Inkomati basin, Mpumalanga, South Africa. This catchment is characterised by a network of wetlands and streams that provide catchment residents with water. The sub-catchment is heavily used, dominated by the agricultural sector and coal mining. To understand the contestation, a contextual analysis was carried out. Selected wetland conditions and ecosystem services, along with user perceptions and the value of wetland-use, were assessed. Wetlands were observably in a relatively healthy condition. The resilience of wetlands and the efficiency of the ecosystem services they offer, especially in mediating water quality, were clear. The early results indicated a healthy landscape despite multiple-user impact from human activity. The health scores and provision of ecosystem services, along with the identified National Freshwater Ecosystem Priority Areas (NFEPAs) and red-listed fauna and flora, provide a substantial grounding for advocating the conservation of the wetlands of the contested X11B catchment. When water quality measures were added to the wetland health and ecosystem service assessment, low pH levels and high electrical conductivity were recorded. Both measures indicate coal mining impacts, more specifically Acid Mine Drainage (AMD) impacts, since AMD typically has sulphate as the dominant salt ion, and high concentrations of trace elements and metal ions. Concentrations breaching the recommended resource quality objectives (RQOs) of trace elements and ions, found in fertilizers and pesticides, were recorded in most sites, suggesting agricultural impacts on the landscape’s hydrology. Further, these agricultural impacts would add to the compromising effect of the wetlands’ capacity to remove pollutants from the water body. Livestock farming on all sites were also near wetlands which may have limited the vegetation cover of grazed land, so increasing runoff and the volume of water entering wetlands and compromising their ecosystem services. Poor water quality has implications for biophysical processes, which play an important role in the functioning of wetlands, for the benefit of users. Without the water quality measures, ecosystem health and ecosystem service methodology used suggested a healthy catchment. However, simple field water quality measures indicated past and present mining impacts. Therefore, the mandatory use of water chemistry is recommended in the assessment of wetlands in catchments with past and present mining activity taking place. Without this, repercussions would include wetland loss, and a more thorough investigation into the water quality and its effects on the wetland ecosystems is suggested. Further ecological investigation of water chemistry (heavy metals, ions, nutrients and trace elements) and macroinvertebrate assemblages identified links to water chemistry impacts on macroinvertebrate abundance and diversity. Abundance results based on the presence, absence and abundance of macroinvertebrates at the different sites did not reveal any clear patterns associated with different landscape users. Diversity, on the other hand, was related to land-use, where sites with high mining use had lower macroinvertebrate diversity than other sites. Related, concurrent, hydro-pedology research produced a more comprehensive understanding of the impact of mining on hydro-connectivity that clearly indicates mining as the cause of long-term deterioration of functional wetland health in a way that is practically impossible to restore. This study suggests that wetlands provide a strong ecosystem service of intermittent resetting of the wetland sediment adsorptive capacity for toxic metal and other salt ions. The hypothesis arising from the work is that, in the case of another heavy rainfall event, the town of Carolina risks another AMD crisis. As sediments are likely to be accumulating and saturated with toxic metal ions. Further AMD-related changes in acidity will increase the mobilisation of adsorbed ions. Future flooding and flushing of wetlands will therefore once again move toxic metal ions through the system, and possibly re-contaminate the Boesmanspruit dam. The value of the study is in delivering specific evidence on the impacts of mining (and to a lesser extent agriculture) on wetland quality. Overall, this study, combined with additional research, indicates that in the X11B catchment, mining impacts are long-term and more serious than agriculture. In terms of contestation the research indicates that reliance on bio-physical data and knowledge is inadequate in resolving conflict between coal mining and other land- and water-users. The study demonstrates the necessity of insight into the social system and the value of a transdisciplinary approach in addressing land-use conflicts and wetland protection.
- Full Text:
- Date Issued: 2018
Morphological and genetic variation of Gymnothorax undulatus (Anguilliformes: Muraenidae) in the Western Indian Ocean
- Authors: Sithole, Yonela
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63722 , vital:28476
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
- Authors: Sithole, Yonela
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63722 , vital:28476
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
Multi-temporal analysis of changes in vegetation distribution in the Great Fish River Game Reserve, Eastern Cape Province, South Africa :1982-2012
- Authors: Dikweni, Sipho
- Date: 2018
- Subjects: Climatic changes -- South Africa|zEastern Cape Biodiversity conservation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10511 , vital:35550
- Description: Great Fish River Game Reserve plays an important role in curtailing the ever-increasing biodiversity declines in Eastern Cape Province and South Africa at large. Though this area plays an important role in the conservation of natural biodiversity, it has been observed that it is undergoing considerable changes with regards to conditions and composition of vegetation cover. These changes signal a decline in the capacity of the Great Fish River Game Reserve to support wildlife population. In this study, remote sensing was used to investigate multi-temporal changes in vegetation distribution in this particular reserve over a period of 30 years (1982-2012). A supervised classification was carried out to classify four Landsat images including; Landsat TM, Landsat ETM and Landsat 8 imagery of 1984, 1992, 2002 and 2013 respectively to map historical and present vegetation conditions and distribution in the Great Fish River Game Reserve. A comparative examination of the classified images showed that there were significant changes in the composition and structure of vegetation with much of the palatable plant species being driven to extinction. The results showed that herbivory pressure inconjuction with climate variability has subsequently resulted in a decrease of the supporting potential of the reserve to sustain wildlife due to mortality of the most preferred plant species and abundant increase of non-palatable plant species. As grazing and browsing intensity increased, there was a decline in regenerative potential of the selected plant species by wild herbivores and successful increase in abundance of the non-palatable plant species. The results of this investigation suggest that the current increase in wildlife population will facilitate the deterioration of habitat condition to support wildlife up to the point of no recovery.
- Full Text:
- Date Issued: 2018
- Authors: Dikweni, Sipho
- Date: 2018
- Subjects: Climatic changes -- South Africa|zEastern Cape Biodiversity conservation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10511 , vital:35550
- Description: Great Fish River Game Reserve plays an important role in curtailing the ever-increasing biodiversity declines in Eastern Cape Province and South Africa at large. Though this area plays an important role in the conservation of natural biodiversity, it has been observed that it is undergoing considerable changes with regards to conditions and composition of vegetation cover. These changes signal a decline in the capacity of the Great Fish River Game Reserve to support wildlife population. In this study, remote sensing was used to investigate multi-temporal changes in vegetation distribution in this particular reserve over a period of 30 years (1982-2012). A supervised classification was carried out to classify four Landsat images including; Landsat TM, Landsat ETM and Landsat 8 imagery of 1984, 1992, 2002 and 2013 respectively to map historical and present vegetation conditions and distribution in the Great Fish River Game Reserve. A comparative examination of the classified images showed that there were significant changes in the composition and structure of vegetation with much of the palatable plant species being driven to extinction. The results showed that herbivory pressure inconjuction with climate variability has subsequently resulted in a decrease of the supporting potential of the reserve to sustain wildlife due to mortality of the most preferred plant species and abundant increase of non-palatable plant species. As grazing and browsing intensity increased, there was a decline in regenerative potential of the selected plant species by wild herbivores and successful increase in abundance of the non-palatable plant species. The results of this investigation suggest that the current increase in wildlife population will facilitate the deterioration of habitat condition to support wildlife up to the point of no recovery.
- Full Text:
- Date Issued: 2018
NetwIOC: a framework for the automated generation of network-based IOCS for malware information sharing and defence
- Authors: Rudman, Lauren Lynne
- Date: 2018
- Subjects: Malware (Computer software) , Computer networks Security measures , Computer security , Python (Computer program language)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60639 , vital:27809
- Description: With the substantial number of new malware variants found each day, it is useful to have an efficient way to retrieve Indicators of Compromise (IOCs) from the malware in a format suitable for sharing and detection. In the past, these indicators were manually created after inspection of binary samples and network traffic. The Cuckoo Sandbox, is an existing dynamic malware analysis system which meets the requirements for the proposed framework and was extended by adding a few custom modules. This research explored a way to automate the generation of detailed network-based IOCs in a popular format which can be used for sharing. This was done through careful filtering and analysis of the PCAP hie generated by the sandbox, and placing these values into the correct type of STIX objects using Python, Through several evaluations, analysis of what type of network traffic can be expected for the creation of IOCs was conducted, including a brief ease study that examined the effect of analysis time on the number of IOCs created. Using the automatically generated IOCs to create defence and detection mechanisms for the network was evaluated and proved successful, A proof of concept sharing platform developed for the STIX IOCs is showcased at the end of the research.
- Full Text:
- Date Issued: 2018
- Authors: Rudman, Lauren Lynne
- Date: 2018
- Subjects: Malware (Computer software) , Computer networks Security measures , Computer security , Python (Computer program language)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60639 , vital:27809
- Description: With the substantial number of new malware variants found each day, it is useful to have an efficient way to retrieve Indicators of Compromise (IOCs) from the malware in a format suitable for sharing and detection. In the past, these indicators were manually created after inspection of binary samples and network traffic. The Cuckoo Sandbox, is an existing dynamic malware analysis system which meets the requirements for the proposed framework and was extended by adding a few custom modules. This research explored a way to automate the generation of detailed network-based IOCs in a popular format which can be used for sharing. This was done through careful filtering and analysis of the PCAP hie generated by the sandbox, and placing these values into the correct type of STIX objects using Python, Through several evaluations, analysis of what type of network traffic can be expected for the creation of IOCs was conducted, including a brief ease study that examined the effect of analysis time on the number of IOCs created. Using the automatically generated IOCs to create defence and detection mechanisms for the network was evaluated and proved successful, A proof of concept sharing platform developed for the STIX IOCs is showcased at the end of the research.
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- Date Issued: 2018