Citizen science, treatment and microbial compliance monitoring in rainwater harvesting in Namibia
- Angala, Hallo Angaleni Nameya
- Authors: Angala, Hallo Angaleni Nameya
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62082 , vital:28105
- Description: Expected release date-April 2020
- Full Text:
- Authors: Angala, Hallo Angaleni Nameya
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62082 , vital:28105
- Description: Expected release date-April 2020
- Full Text:
Towards understanding the effect of size variation on the aggressive and feeding behaviours of juvenile dusky kob Argyrosomus japonicus (Pisces: Sciaenidae)
- Authors: Babane, Siviwe Elvis
- Date: 2018
- Subjects: Argyrosomus -- Feeding and feeds , Aquaculture , Fishes -- Cannibalism , Fishes -- Feeding and feeds
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59592 , vital:27629
- Description: Many studies have been conducted on the effect of size-grading in other fish species. However, there is a paucity of scientific information on the effects of size variation on cannibalism of juvenile dusky kob. Thus, a study focusing on the effect of size variation on juvenile dusky kob aggressive and feeding (browsing) behaviours was conducted. Three separate groups of hatchery-reared juvenile dusky kob of were obtained from Oceanwise (Pty) Ltd for use in a series of three experimental trials. In all trials, juvenile fish of the same age were size-graded and the COV-value was used to determine the size variation. The focal fish (largest fish) was exposed to groups of fish with different size variation for 30-min. behavioural observations before and after feeding in randomised trials. The first experimental trial (Chapter 2) quantified the effect of increasing size variation and observation time on the aggressive and browsing behaviours of juvenile dusky kob. On average, juvenile dusky kob weighed 3.60 ± 0.68 g fish-1 and measured 5.8 ± 0.41 mm. Each focal fish was observed (a) before feeding in the morning, (b) 2 h after feeding, (c) 6 h after feeding and (d) 12 h after feeding. Fish increased browsing behaviours (averaging 6.60 ± 0.56) and decreased intimidating aggressive behaviours (18.60 ± 1.39) 12 h after feeding. Other aggressive behaviours occurred but did not differ between observation times. Aggressive and browsing behaviours positively correlated with size variation variables, predominantly, 12 h after feeding. An average frequency of 19 chases were observed positively correlated with size variation, followed by average frequencies of 17 body bites and browses, and 11 tail bites per 30 min. Some behaviours including average frequencies of 0.2 chases, 4 tail bites, 2.4 intimidating and 0.3 browsing behaviours negatively correlated with the size variation, generally closer to the last meal. These preliminary observations thus showed that fish have become hungry approximately 6-12 h after feeding and substituted certain behaviours for others as time after feeding passed and as size variation increased. The second experimental trial (Chapter 3) consisted of the observations further testing the relationship between aggressive behaviours and size variation of juveniles of dusky kob averaging 0.43 ± 0.27 g fish-1. The focal fish was exposed to groups of fish of four size variation (COV) treatments for observations before and 12 h after feeding. Aggressive behaviours positively correlated with size variation both before and 12 h after feeding. An average frequency of 437 body bites positively correlated more often with COV, followed by average frequencies of 365 intimidating behaviours and 199 tail bites per 30 min., respectively, before and 12 h after feeding. The least often exhibited aggressive behaviours averaged 26 chases while positively correlating with size variation on the times specified. An average frequency of 311 intimidating behaviours before and after feeding including average of 28 tail bites after feeding negatively correlated with size variation. This may relate to shift of behaviours depending on the needs and capacity of the fish. Apparently, aggressive fish can change its behaviour as a function of COV-values rather than the mean size of the other fish. The third trial (Chapter 4) investigated the effect of the aggressor’s (focal fish) size in relation its aggressive and browsing behaviours to other fish (non-focal fish). Juvenile fish used for this trial, on average, weighed 30 ± 7.63 g fish-1. Aggressive and browsing behaviours were observed in four treatments of a) high COV and mean weight below, b) low COV and mean weight less, c) high COV and mean weight equivalent to and d) low COV and mean weight higher than that of the focal fish. Increased frequencies of aggressive and browsing behaviours per 30 min. occurred in treatment A, sharing similar frequencies in treatment C, compared to the other treatments (B and D) which shared certain frequencies. The intimidating behaviours predominated, followed by browsing, body bites, chases and tail bites, respectively. The results of the overall study suggest that the time passed after feeding and increasing size variation and differences facilitated aggressive and browsing behaviours in juvenile dusky kob. Dusky kob showed increasing aggressive behaviours as early as in the first two weeks after hatching, averaging 0.43 ± 0.27 g fish-1 with the frequency correlating with size differences. Consistent size-grading technique in the same-age fish should be used to manage size variation associated with aggressive behaviours. The period of about 4-6 h after feeding may explain the noticeable increased aggressive and browsing behaviours. Thus, fish should be fed immediately before or after evacuation of their guts to maintain less-aggressive behaviours of juvenile dusky kob. Fish generally increased aggressive and browsing acts before and long time after feeding than closer to after feeding. The study has provided the fundamental scientific groundwork for fish farmers and future researchers can further explore size variation, time after feeding and gut evacuation rate as critical components of aggressive behaviours. The scientific knowledge of aggressive and cannibalistic behaviours has essential application in farming management to achieve improved survival and growth rates in juvenile fish.
- Full Text:
- Authors: Babane, Siviwe Elvis
- Date: 2018
- Subjects: Argyrosomus -- Feeding and feeds , Aquaculture , Fishes -- Cannibalism , Fishes -- Feeding and feeds
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59592 , vital:27629
- Description: Many studies have been conducted on the effect of size-grading in other fish species. However, there is a paucity of scientific information on the effects of size variation on cannibalism of juvenile dusky kob. Thus, a study focusing on the effect of size variation on juvenile dusky kob aggressive and feeding (browsing) behaviours was conducted. Three separate groups of hatchery-reared juvenile dusky kob of were obtained from Oceanwise (Pty) Ltd for use in a series of three experimental trials. In all trials, juvenile fish of the same age were size-graded and the COV-value was used to determine the size variation. The focal fish (largest fish) was exposed to groups of fish with different size variation for 30-min. behavioural observations before and after feeding in randomised trials. The first experimental trial (Chapter 2) quantified the effect of increasing size variation and observation time on the aggressive and browsing behaviours of juvenile dusky kob. On average, juvenile dusky kob weighed 3.60 ± 0.68 g fish-1 and measured 5.8 ± 0.41 mm. Each focal fish was observed (a) before feeding in the morning, (b) 2 h after feeding, (c) 6 h after feeding and (d) 12 h after feeding. Fish increased browsing behaviours (averaging 6.60 ± 0.56) and decreased intimidating aggressive behaviours (18.60 ± 1.39) 12 h after feeding. Other aggressive behaviours occurred but did not differ between observation times. Aggressive and browsing behaviours positively correlated with size variation variables, predominantly, 12 h after feeding. An average frequency of 19 chases were observed positively correlated with size variation, followed by average frequencies of 17 body bites and browses, and 11 tail bites per 30 min. Some behaviours including average frequencies of 0.2 chases, 4 tail bites, 2.4 intimidating and 0.3 browsing behaviours negatively correlated with the size variation, generally closer to the last meal. These preliminary observations thus showed that fish have become hungry approximately 6-12 h after feeding and substituted certain behaviours for others as time after feeding passed and as size variation increased. The second experimental trial (Chapter 3) consisted of the observations further testing the relationship between aggressive behaviours and size variation of juveniles of dusky kob averaging 0.43 ± 0.27 g fish-1. The focal fish was exposed to groups of fish of four size variation (COV) treatments for observations before and 12 h after feeding. Aggressive behaviours positively correlated with size variation both before and 12 h after feeding. An average frequency of 437 body bites positively correlated more often with COV, followed by average frequencies of 365 intimidating behaviours and 199 tail bites per 30 min., respectively, before and 12 h after feeding. The least often exhibited aggressive behaviours averaged 26 chases while positively correlating with size variation on the times specified. An average frequency of 311 intimidating behaviours before and after feeding including average of 28 tail bites after feeding negatively correlated with size variation. This may relate to shift of behaviours depending on the needs and capacity of the fish. Apparently, aggressive fish can change its behaviour as a function of COV-values rather than the mean size of the other fish. The third trial (Chapter 4) investigated the effect of the aggressor’s (focal fish) size in relation its aggressive and browsing behaviours to other fish (non-focal fish). Juvenile fish used for this trial, on average, weighed 30 ± 7.63 g fish-1. Aggressive and browsing behaviours were observed in four treatments of a) high COV and mean weight below, b) low COV and mean weight less, c) high COV and mean weight equivalent to and d) low COV and mean weight higher than that of the focal fish. Increased frequencies of aggressive and browsing behaviours per 30 min. occurred in treatment A, sharing similar frequencies in treatment C, compared to the other treatments (B and D) which shared certain frequencies. The intimidating behaviours predominated, followed by browsing, body bites, chases and tail bites, respectively. The results of the overall study suggest that the time passed after feeding and increasing size variation and differences facilitated aggressive and browsing behaviours in juvenile dusky kob. Dusky kob showed increasing aggressive behaviours as early as in the first two weeks after hatching, averaging 0.43 ± 0.27 g fish-1 with the frequency correlating with size differences. Consistent size-grading technique in the same-age fish should be used to manage size variation associated with aggressive behaviours. The period of about 4-6 h after feeding may explain the noticeable increased aggressive and browsing behaviours. Thus, fish should be fed immediately before or after evacuation of their guts to maintain less-aggressive behaviours of juvenile dusky kob. Fish generally increased aggressive and browsing acts before and long time after feeding than closer to after feeding. The study has provided the fundamental scientific groundwork for fish farmers and future researchers can further explore size variation, time after feeding and gut evacuation rate as critical components of aggressive behaviours. The scientific knowledge of aggressive and cannibalistic behaviours has essential application in farming management to achieve improved survival and growth rates in juvenile fish.
- Full Text:
Developing a citizen technician based approach to suspended sediment monitoring in the Tsitsa River catchment, Eastern Cape, South Africa
- Authors: Bannatyne, Laura Joan
- Date: 2018
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Suspended sediments -- South Africa -- Eastern Cape , Suspended sediments -- Monitoring -- Citizen participation , Tsitsa River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62593 , vital:28211
- Description: Suspended sediment (SS) in channels is spatiotemporally heterogeneous and, over the long term, is known to be moved predominantly by flood flows with return periods of ~1 - 1.5 years. Flood flows in the Tsitsa catchment (Eastern Cape Province, South Africa) are unpredictable, and display a wide range of discharges. Direct, flood-focused SS sampling at sub-catchment scale was required to provide a SS baseline against which to monitor the impact on SS of catchment rehabilitation interventions, to determine the relative contributions of sub-catchments to SS loads and yields at the site of the proposed Ntabelanga Dam wall, and to verify modelled SS baselines, loads and yields. Approaches to SS sampling relying on researcher presence and/or installed equipment to adequately monitor SS through flood flows were precluded by cost, and the physical and socioeconomic conditions in the project area. A citizen technician (CT)-based flood-focused approach to direct SS sampling was developed and implemented. It was assessed in terms of its efficiency and effectiveness, the proficiency of the laboratory analysis methods, and the accuracy of the resulting SS data. A basic laboratory protocol for SSC analysis was developed, but is not the focus of this thesis. Using basic sampling equipment and smartphone-based reporting protocols, local residents at eleven points on the Tsitsa River and its major tributaries were employed as CTs. They were paid to take water samples during daylight hours at sub-daily timestep, with the emphasis on sampling through flood flows. The method was innovative in that it opted for manual sampling against a global trend towards instrumentation. Whilst the management of CTs formed a significant project component, the CTs benefitted directly through remuneration and work experience opportunities. The sampling method was evaluated at four sites from December 2015 - May 2016. The CTs were found to have efficiently and effectively sampled SS through a range of water levels, particularly in the main Tsitsa channel. An acceptable level of proficiency and accuracy was achieved, and many flood events were successfully defined by multiple data points. The method was chiefly limited by the inability of CTs to sample overnight rises and peaks occurring as a result of afternoon thunderstorms, particularly in small tributaries. The laboratory process was responsible for some losses in proficiency and accuracy. Improved laboratory quality control was therefore recommended. The CT-based approach can be adapted to other spatial and temporal scales in other areas, and to other environmental monitoring applications.
- Full Text:
- Authors: Bannatyne, Laura Joan
- Date: 2018
- Subjects: Sediments (Geology) -- Management , Sediments (Geology) -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Suspended sediments -- South Africa -- Eastern Cape , Suspended sediments -- Monitoring -- Citizen participation , Tsitsa River
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62593 , vital:28211
- Description: Suspended sediment (SS) in channels is spatiotemporally heterogeneous and, over the long term, is known to be moved predominantly by flood flows with return periods of ~1 - 1.5 years. Flood flows in the Tsitsa catchment (Eastern Cape Province, South Africa) are unpredictable, and display a wide range of discharges. Direct, flood-focused SS sampling at sub-catchment scale was required to provide a SS baseline against which to monitor the impact on SS of catchment rehabilitation interventions, to determine the relative contributions of sub-catchments to SS loads and yields at the site of the proposed Ntabelanga Dam wall, and to verify modelled SS baselines, loads and yields. Approaches to SS sampling relying on researcher presence and/or installed equipment to adequately monitor SS through flood flows were precluded by cost, and the physical and socioeconomic conditions in the project area. A citizen technician (CT)-based flood-focused approach to direct SS sampling was developed and implemented. It was assessed in terms of its efficiency and effectiveness, the proficiency of the laboratory analysis methods, and the accuracy of the resulting SS data. A basic laboratory protocol for SSC analysis was developed, but is not the focus of this thesis. Using basic sampling equipment and smartphone-based reporting protocols, local residents at eleven points on the Tsitsa River and its major tributaries were employed as CTs. They were paid to take water samples during daylight hours at sub-daily timestep, with the emphasis on sampling through flood flows. The method was innovative in that it opted for manual sampling against a global trend towards instrumentation. Whilst the management of CTs formed a significant project component, the CTs benefitted directly through remuneration and work experience opportunities. The sampling method was evaluated at four sites from December 2015 - May 2016. The CTs were found to have efficiently and effectively sampled SS through a range of water levels, particularly in the main Tsitsa channel. An acceptable level of proficiency and accuracy was achieved, and many flood events were successfully defined by multiple data points. The method was chiefly limited by the inability of CTs to sample overnight rises and peaks occurring as a result of afternoon thunderstorms, particularly in small tributaries. The laboratory process was responsible for some losses in proficiency and accuracy. Improved laboratory quality control was therefore recommended. The CT-based approach can be adapted to other spatial and temporal scales in other areas, and to other environmental monitoring applications.
- Full Text:
A reconciliation study of different resource estimation methods and drill hole spacing as applied to the Langer Heinrich calcrete-hosted uranium deposit, Namibia
- Authors: Baufeldt, Sven
- Date: 2018
- Subjects: Uranium -- Namibia , Calcretes -- Namibia , Carnotite -- Namibia , Uranium mines and mining -- Namibia , Uranium ores -- Geology -- Namibia , Langer-Heinrich Uranium mine
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62527 , vital:28203
- Description: The Langer Heinrich calcrete hosted uranium deposit is situated approximately 90 km to east of the coastal town of Swakopmund in Namibia. It is run by an Australian owned company, Paladin Energy Limited, along with China National Nuclear Corporation (CNNC) who maintain 25% of the shares. Production commenced in 2007 and has been ongoing. Carnotite is the primary and only ore mineral, and the nature of mineralisation within the Langer Heinrich palaeo channel dictates westward-directed continuous open pit mining. Smaller-scale 1micro pits target near-surface, high-grade, lenses toward the east. The high variability in uranium grade over relatively short distances complicates the grade estimation process. This combined with a low uranium price, and a study aimed at optimising of mine production is one of the key drivers for the research presented in this thesis. The efficacy of four resource estimation techniques, commonly used in the mining industry, are investigated by application to variable exploration, infill drilling and grade-control drill pattern spacing. The drill spacing includes regular grids of 50 m x 50 m, 25 m x 25 m and 12,5 m x 12,5 m exploration data. Also included is grade control drill data, drilled on a 4 m x 4 m spacing. The current selective mining unit (SMU) is 4mE x 4mN x 3mRl which is an indication of the minimum dimension whereby the loading equipment can separate ore from waste. The two datasets are processed by four estimation techniques: Inverse Distance Weighting (IDW, squared and cubed), Ordinary Kriging (OK), Multiple Indicator Kriging (MIK) and Conditional Simulation (CS). The two datasets consisted of real-time mining data from pit G1 (micro-pit) in the eastern parts of the mining licence, and pit H1 (continuous larger open pit) in the western area of the palaeo channel. The reconciliation project aims to provide results suitable for devising optimised mining strategies, particularly in future targets where drill spacing can perhaps be improved to provide suitable data with a greater cost saving strategy. Along with the optimal drill spacing or combination thereof, a preferred estimation technique can be suggested and recommended for future operations that involve mining of surficial calcrete-hosted uranium deposits. Results of this study show that 12,5 m x 12,5 m drill spacing provided estimation accuracies similar to that of the narrow 4 m x 4 m grade control spacing (blast hole drilling spacing). The 12,5 m x 12,5m spacing has potential for accurate grade estimations during mining, and could be supplemented by infill downhole radiometric logging on a 4 m x 4 m spacing when 1 Micro pit: Small pits within palaeo channel usually targeted for their near surface high-grade ore necessary. In general, Multiple Indicator Kriging (MIK) provided the most accurate and robust estimations on the wider spaced exploration data and conditional simulation (CS) proved more efficient on the narrow grade control data. These results correspond with current exploration practices for surficial uranium deposits world-wide. Deposit type, therefore complexity and hence SMU sizes play a pivotal role in drill hole planning and estimation accuracies.
- Full Text:
- Authors: Baufeldt, Sven
- Date: 2018
- Subjects: Uranium -- Namibia , Calcretes -- Namibia , Carnotite -- Namibia , Uranium mines and mining -- Namibia , Uranium ores -- Geology -- Namibia , Langer-Heinrich Uranium mine
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62527 , vital:28203
- Description: The Langer Heinrich calcrete hosted uranium deposit is situated approximately 90 km to east of the coastal town of Swakopmund in Namibia. It is run by an Australian owned company, Paladin Energy Limited, along with China National Nuclear Corporation (CNNC) who maintain 25% of the shares. Production commenced in 2007 and has been ongoing. Carnotite is the primary and only ore mineral, and the nature of mineralisation within the Langer Heinrich palaeo channel dictates westward-directed continuous open pit mining. Smaller-scale 1micro pits target near-surface, high-grade, lenses toward the east. The high variability in uranium grade over relatively short distances complicates the grade estimation process. This combined with a low uranium price, and a study aimed at optimising of mine production is one of the key drivers for the research presented in this thesis. The efficacy of four resource estimation techniques, commonly used in the mining industry, are investigated by application to variable exploration, infill drilling and grade-control drill pattern spacing. The drill spacing includes regular grids of 50 m x 50 m, 25 m x 25 m and 12,5 m x 12,5 m exploration data. Also included is grade control drill data, drilled on a 4 m x 4 m spacing. The current selective mining unit (SMU) is 4mE x 4mN x 3mRl which is an indication of the minimum dimension whereby the loading equipment can separate ore from waste. The two datasets are processed by four estimation techniques: Inverse Distance Weighting (IDW, squared and cubed), Ordinary Kriging (OK), Multiple Indicator Kriging (MIK) and Conditional Simulation (CS). The two datasets consisted of real-time mining data from pit G1 (micro-pit) in the eastern parts of the mining licence, and pit H1 (continuous larger open pit) in the western area of the palaeo channel. The reconciliation project aims to provide results suitable for devising optimised mining strategies, particularly in future targets where drill spacing can perhaps be improved to provide suitable data with a greater cost saving strategy. Along with the optimal drill spacing or combination thereof, a preferred estimation technique can be suggested and recommended for future operations that involve mining of surficial calcrete-hosted uranium deposits. Results of this study show that 12,5 m x 12,5 m drill spacing provided estimation accuracies similar to that of the narrow 4 m x 4 m grade control spacing (blast hole drilling spacing). The 12,5 m x 12,5m spacing has potential for accurate grade estimations during mining, and could be supplemented by infill downhole radiometric logging on a 4 m x 4 m spacing when 1 Micro pit: Small pits within palaeo channel usually targeted for their near surface high-grade ore necessary. In general, Multiple Indicator Kriging (MIK) provided the most accurate and robust estimations on the wider spaced exploration data and conditional simulation (CS) proved more efficient on the narrow grade control data. These results correspond with current exploration practices for surficial uranium deposits world-wide. Deposit type, therefore complexity and hence SMU sizes play a pivotal role in drill hole planning and estimation accuracies.
- Full Text:
The effect of water temperature on the distribution of the Eastern Cape redfin minnow, Pseudobarbus afer (Peters, 1864)
- Authors: Bloy, Lesley Elizabeth
- Date: 2018
- Subjects: Minnows -- South Africa -- Eastern Cape , Cyprinidae -- South Africa -- Eastern Cape , Minnows -- Effect of temperature on -- South Africa -- Eastern Cape , Minnows -- Effect of exotic animals on -- South Africa -- Eastern Cape , Introduced organisms -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62017 , vital:28096
- Description: The main objective of this MSc study was to disentangle whether temperature or the presence of non-native fish was limiting the distribution of Pseudobarbus afer (Peters, 1864) in the Blindekloof stream, Eastern Cape, South Africa. The aims were to: i) describe the thermal regime of the Blindekloof stream; ii) conduct experiments to determine the preferred and critical temperatures of P. afer and; iii) use snorkel surveys to contextualise the distribution of both native and non-native fishes in the Blindekloof stream to assess whether the downstream distribution of P. afer was likely to be influenced by temperature or by the presence of non-native, predatory fishes. To describe the thermal regime, year-long temperature data from four long term monitoring sites in the Blindekloof stream were collected using Hobo temperature loggers and analysed in order to better understand the thermal profile, the thermal variation and the rate of temperature change in the stream. The warmest temperatures were recorded in late December 2015 (absolute maximum of 29.4 °C). The coolest water temperatures were recorded in early August 2015 (absolute minimum of 9.5 °C). There is both seasonal and diel variation in temperature with mean, minimum, maximum, 7 day mean, 7 day maximum and temperature ranges differing significantly between sites. With knowledge of the thermal regime of a monitored reach of the Blindekloof stream, the thermal tolerance and preference of P. afer were investigated. The thermal tolerance of P. afer was investigated using the Critical Thermal Method (CTM) which uses non-lethal endpoints (the loss of equilibrium). At low acclimatization temperatures (11.9 ± 0.7 °C), the mean CTmax of P. afer was found to be 29.9 ± 0.7 °C, while at a higher acclimatization temperature (19.9 ± 0.1 °C), the mean CTmax was 35.1 ± 0.6°C. Custom-built thermal choice tanks were used to investigate the thermal preference of P. afer in both summer and winter. The preferred median temperatures for the summer experiments ranged from 22.4 - 29.3 °C while the winter preferred median temperatures ranged from 18.5 - 23.1 °C. The thermal tolerance of P. afer was compared to the thermal regime of the stream and the results suggest that temperature is not limiting the distribution of P. afer. Snorkel surveys were used to determine the distribution of fishes in the Blindekloof stream. Analysis of the distribution data suggests that, in the absence of non-native predatory species, native fishes have the potential to inhabit pools throughout the system right to the confluence, thus predatory fishes and not temperature was limiting P. afer distributions.
- Full Text:
- Authors: Bloy, Lesley Elizabeth
- Date: 2018
- Subjects: Minnows -- South Africa -- Eastern Cape , Cyprinidae -- South Africa -- Eastern Cape , Minnows -- Effect of temperature on -- South Africa -- Eastern Cape , Minnows -- Effect of exotic animals on -- South Africa -- Eastern Cape , Introduced organisms -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62017 , vital:28096
- Description: The main objective of this MSc study was to disentangle whether temperature or the presence of non-native fish was limiting the distribution of Pseudobarbus afer (Peters, 1864) in the Blindekloof stream, Eastern Cape, South Africa. The aims were to: i) describe the thermal regime of the Blindekloof stream; ii) conduct experiments to determine the preferred and critical temperatures of P. afer and; iii) use snorkel surveys to contextualise the distribution of both native and non-native fishes in the Blindekloof stream to assess whether the downstream distribution of P. afer was likely to be influenced by temperature or by the presence of non-native, predatory fishes. To describe the thermal regime, year-long temperature data from four long term monitoring sites in the Blindekloof stream were collected using Hobo temperature loggers and analysed in order to better understand the thermal profile, the thermal variation and the rate of temperature change in the stream. The warmest temperatures were recorded in late December 2015 (absolute maximum of 29.4 °C). The coolest water temperatures were recorded in early August 2015 (absolute minimum of 9.5 °C). There is both seasonal and diel variation in temperature with mean, minimum, maximum, 7 day mean, 7 day maximum and temperature ranges differing significantly between sites. With knowledge of the thermal regime of a monitored reach of the Blindekloof stream, the thermal tolerance and preference of P. afer were investigated. The thermal tolerance of P. afer was investigated using the Critical Thermal Method (CTM) which uses non-lethal endpoints (the loss of equilibrium). At low acclimatization temperatures (11.9 ± 0.7 °C), the mean CTmax of P. afer was found to be 29.9 ± 0.7 °C, while at a higher acclimatization temperature (19.9 ± 0.1 °C), the mean CTmax was 35.1 ± 0.6°C. Custom-built thermal choice tanks were used to investigate the thermal preference of P. afer in both summer and winter. The preferred median temperatures for the summer experiments ranged from 22.4 - 29.3 °C while the winter preferred median temperatures ranged from 18.5 - 23.1 °C. The thermal tolerance of P. afer was compared to the thermal regime of the stream and the results suggest that temperature is not limiting the distribution of P. afer. Snorkel surveys were used to determine the distribution of fishes in the Blindekloof stream. Analysis of the distribution data suggests that, in the absence of non-native predatory species, native fishes have the potential to inhabit pools throughout the system right to the confluence, thus predatory fishes and not temperature was limiting P. afer distributions.
- Full Text:
In silico characterization of plasmodial transketolases as potential malaria drug target
- Authors: Boateng, Rita Afriyie
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63540 , vital:28433
- Description: Expected release date-April 2019
- Full Text:
- Authors: Boateng, Rita Afriyie
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63540 , vital:28433
- Description: Expected release date-April 2019
- Full Text:
The role of field and garden cultivation for food security under a changing climate: the case of Fairbairn and Ntloko villages, Eastern Cape
- Authors: Brooks, Haydn
- Date: 2018
- Subjects: Climatic changes -- Economic aspects -- Eastern Cape (South Africa) , Climatic changes -- Social aspects -- South Africa , Food -- Economic aspects -- South Africa , Food security -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58013 , vital:27019
- Description: The world is becoming more complex due to the increasing occurrence of social-ecological change. This is particularly evident in the developing world, especially on the African continent, where existing vulnerabilities (i.e. endemic poverty, weak governance, overpopulation and HIV/AIDS) are being exacerbated by the impact of climate change. Climate change poses a very real threat to millions of Africans, especially those who rely on the natural world for their livelihoods. The increasing variability of climate and rainfall patterns are said to have dire consequences on agricultural production which is the main livelihood activity of rural dwellers across the continent. The impacts of such change and variability include, changes in the frequency and intensity of droughts, flooding and heavy storms, leading to worsening soil conditions, desertification as well as disease and pest out-breaks which will likely result in reduced crop and livestock yields. A reduction in agricultural production will likely have a negative effect on the food security of millions of people. This study was conducted in the Eastern Cape of South Africa, in two rural villages, Fairbairn and Ntloko located in the former Ciskei homeland, with the purpose of exploring the nexus between climate change, cultivation and food security. This study combined social-ecological thinking with that of political ecology to create a robust lens, in which to analyse the complex interactions between humans and the environment. A mixed methods approach was used to gather the data which consisted of a household survey, using a structured questionnaire as well as semi-structured interviews with various respondents. Quantitative data were analysed using Excel and Statistica 13, whilst coding was used for qualitative data. The main aim of the study was to explore the extent and characteristics of cultivation in the two study sites, the role of household food production in food security as well as the challenges that local cultivator’s face with regards to climate change. In recent decades, there has been a decline in rural agricultural production with many fields that were previously cultivated, lying vacant and unused. However, as this study found, cultivation is still important as over 50% of sampled households cultivated a small area within the homestead. This was mainly done to supplement household food expenditure in order to save cash incomes. The results also found that although participants had perceived negative changes in climate and rainfall (amount, onset, duration), it was not considered the most important challenge for own production. Rather, lack of fencing and capital were seen as major hindrances to efficient own production. Understanding the complexity of own production and food security under a changing climate can help form better and more resilient policies and strategies for rural development, in addition to strengthening future livelihoods of rural people in an ever changing world.
- Full Text:
- Authors: Brooks, Haydn
- Date: 2018
- Subjects: Climatic changes -- Economic aspects -- Eastern Cape (South Africa) , Climatic changes -- Social aspects -- South Africa , Food -- Economic aspects -- South Africa , Food security -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58013 , vital:27019
- Description: The world is becoming more complex due to the increasing occurrence of social-ecological change. This is particularly evident in the developing world, especially on the African continent, where existing vulnerabilities (i.e. endemic poverty, weak governance, overpopulation and HIV/AIDS) are being exacerbated by the impact of climate change. Climate change poses a very real threat to millions of Africans, especially those who rely on the natural world for their livelihoods. The increasing variability of climate and rainfall patterns are said to have dire consequences on agricultural production which is the main livelihood activity of rural dwellers across the continent. The impacts of such change and variability include, changes in the frequency and intensity of droughts, flooding and heavy storms, leading to worsening soil conditions, desertification as well as disease and pest out-breaks which will likely result in reduced crop and livestock yields. A reduction in agricultural production will likely have a negative effect on the food security of millions of people. This study was conducted in the Eastern Cape of South Africa, in two rural villages, Fairbairn and Ntloko located in the former Ciskei homeland, with the purpose of exploring the nexus between climate change, cultivation and food security. This study combined social-ecological thinking with that of political ecology to create a robust lens, in which to analyse the complex interactions between humans and the environment. A mixed methods approach was used to gather the data which consisted of a household survey, using a structured questionnaire as well as semi-structured interviews with various respondents. Quantitative data were analysed using Excel and Statistica 13, whilst coding was used for qualitative data. The main aim of the study was to explore the extent and characteristics of cultivation in the two study sites, the role of household food production in food security as well as the challenges that local cultivator’s face with regards to climate change. In recent decades, there has been a decline in rural agricultural production with many fields that were previously cultivated, lying vacant and unused. However, as this study found, cultivation is still important as over 50% of sampled households cultivated a small area within the homestead. This was mainly done to supplement household food expenditure in order to save cash incomes. The results also found that although participants had perceived negative changes in climate and rainfall (amount, onset, duration), it was not considered the most important challenge for own production. Rather, lack of fencing and capital were seen as major hindrances to efficient own production. Understanding the complexity of own production and food security under a changing climate can help form better and more resilient policies and strategies for rural development, in addition to strengthening future livelihoods of rural people in an ever changing world.
- Full Text:
A mineralogical, geochemical and metallogenic study of unusual Mn/Na/Ba assemblages at the footwall of conglomeratic iron-ore at farm Langverwacht, Northern Cape Province of South Africa
- Authors: Bursey, James Rodney
- Date: 2018
- Subjects: Iron ores -- Geology -- South Africa -- Northern Cape , Conglomerate -- South Africa -- Northern Cape , Petrology -- South Africa -- Northern Cape , Manganese -- South Africa -- Northern Cape , Sodium -- South Africa -- Northern Cape , Barium -- South Africa -- Northern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62516 , vital:28201
- Description: The Postmasburg Manganese Field (PMF), located in the Northern Cape province of South Africa, plays host to significant deposits of iron and manganese that have been utilized since their discovery in 1922 by Captain L.T. Shone. Further afield, lies the massive high-grade manganese deposit of the Kalahari Manganese Field (KMF), which drew attention away from the PMF after its discovery. These deposits are not limited to iron and manganese ore, but contain significant assemblages of alkali-rich rocks - which is the focus of this study. The existence of alkali-rich assemblages beneath conglomeratic iron-ore on farm Langwervacht, has come under investigation in this study, and in particular, the enrichment of these rocks in Ba, Na and Mn. Petrographic analysis of the clast-supported conglomerate unit (ore-zone), has uncovered the presence of vugs (up to 8mm across) which contain barite, K-feldspar and fluorapatite. In addition to this, the ore-zone of one of the three boreholes contains late carbonate veins (kutnohorite), which travel along Fe-clast boundaries, and exploit clast-fractures and areas of weakness. Further down, within the ‘enriched-zone’ of alkalis, the mineralogy is more diverse - containing elevated concentrations of Ba, Na and Mn. Seventeen distinct minerals containing these three key elements have been identified - along with one solid-solution series in the form of hollandite-coronadite. The existence of minerals such as natrolite, aegirine, albite, banalsite, barite, serandite, celsian and hollandite-coronadite are indicative of hydrothermal activity having influenced these rocks. Bulk-geochemistry was used to compare the major and trace elements of each borehole and the associated units. Both the trace elements and the REE’s from the ore-zone are enriched by an average of 5-10x relative to the BIF standard used - which immediately suggests an influx of elements. Compared to PAAS (Post Archaean Australian Shales), the ore-zone REE’s are slightly depleted, but more importantly the profiles are very similar to that of the Mapedi shales achieved in previous studies. This result points towards a strong shale influence in the ore-zone protolith. Expectedly, many of the enriched-zone trace elements and REE’s show far greater enrichment than what is observed in the ore-zone. Trace and Rare Earth Element profiles between the ore-zone and the enriched-zone are, however, generally correlative, with profiles reflecting similar enrichments and depletions for a given element - even within different rock units. This suggests that the hydrothermal fluid has moved in a general upward direction, reacting with host-rock units, and relinquishing elements carried in solution - wherever conditions have been favourable for the accommodation of these elements. This study has shed light on the relationship between the ore-zone and the enriched-zone, and results suggest that the process of alkali enrichment is not directly related to the process of upgrading of the iron ores. This is due to the extent of the alkali-enrichment below the ore-zone, as well as enrichment factors in some trace elements being superior to that of Fe2O3 in the ore- zone. Hence, both of these zones have both been affected by a later hydrothermal fluid. The source of the fluid is likely a mature basinal brine, of oxidized, alkaline nature - which leached elements (Ba, K, Na, Pb, Ca) from older rocks, and carried them in solution. On a local-scale, this fluid has exploited areas of weakness in the form of fractures, less consolidated conglomeratic material and crosscutting veins. Manganese and iron has been remobilized on a local scale - producing secondary textures and partitioning into phases such as Mn-rich calcite and serandite. Comparisons to other studies in the PMF and KMF have revealed very similar alkali-rich assemblages, bearing many of the same minerals observed in this study - even within more manganiferous deposits. These findings have led to suggestions of a possible regional-scale hydrothermal overprint, which may have imparted a similar geochemical signal over the entire region - with the assistance of faults and unconformities. Of course, proving this is no mean feat, but current work on the source of barium in barite, using Sr isotopes from samples across the region may shed light on the source of at least one key element of these deposits.
- Full Text:
- Authors: Bursey, James Rodney
- Date: 2018
- Subjects: Iron ores -- Geology -- South Africa -- Northern Cape , Conglomerate -- South Africa -- Northern Cape , Petrology -- South Africa -- Northern Cape , Manganese -- South Africa -- Northern Cape , Sodium -- South Africa -- Northern Cape , Barium -- South Africa -- Northern Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62516 , vital:28201
- Description: The Postmasburg Manganese Field (PMF), located in the Northern Cape province of South Africa, plays host to significant deposits of iron and manganese that have been utilized since their discovery in 1922 by Captain L.T. Shone. Further afield, lies the massive high-grade manganese deposit of the Kalahari Manganese Field (KMF), which drew attention away from the PMF after its discovery. These deposits are not limited to iron and manganese ore, but contain significant assemblages of alkali-rich rocks - which is the focus of this study. The existence of alkali-rich assemblages beneath conglomeratic iron-ore on farm Langwervacht, has come under investigation in this study, and in particular, the enrichment of these rocks in Ba, Na and Mn. Petrographic analysis of the clast-supported conglomerate unit (ore-zone), has uncovered the presence of vugs (up to 8mm across) which contain barite, K-feldspar and fluorapatite. In addition to this, the ore-zone of one of the three boreholes contains late carbonate veins (kutnohorite), which travel along Fe-clast boundaries, and exploit clast-fractures and areas of weakness. Further down, within the ‘enriched-zone’ of alkalis, the mineralogy is more diverse - containing elevated concentrations of Ba, Na and Mn. Seventeen distinct minerals containing these three key elements have been identified - along with one solid-solution series in the form of hollandite-coronadite. The existence of minerals such as natrolite, aegirine, albite, banalsite, barite, serandite, celsian and hollandite-coronadite are indicative of hydrothermal activity having influenced these rocks. Bulk-geochemistry was used to compare the major and trace elements of each borehole and the associated units. Both the trace elements and the REE’s from the ore-zone are enriched by an average of 5-10x relative to the BIF standard used - which immediately suggests an influx of elements. Compared to PAAS (Post Archaean Australian Shales), the ore-zone REE’s are slightly depleted, but more importantly the profiles are very similar to that of the Mapedi shales achieved in previous studies. This result points towards a strong shale influence in the ore-zone protolith. Expectedly, many of the enriched-zone trace elements and REE’s show far greater enrichment than what is observed in the ore-zone. Trace and Rare Earth Element profiles between the ore-zone and the enriched-zone are, however, generally correlative, with profiles reflecting similar enrichments and depletions for a given element - even within different rock units. This suggests that the hydrothermal fluid has moved in a general upward direction, reacting with host-rock units, and relinquishing elements carried in solution - wherever conditions have been favourable for the accommodation of these elements. This study has shed light on the relationship between the ore-zone and the enriched-zone, and results suggest that the process of alkali enrichment is not directly related to the process of upgrading of the iron ores. This is due to the extent of the alkali-enrichment below the ore-zone, as well as enrichment factors in some trace elements being superior to that of Fe2O3 in the ore- zone. Hence, both of these zones have both been affected by a later hydrothermal fluid. The source of the fluid is likely a mature basinal brine, of oxidized, alkaline nature - which leached elements (Ba, K, Na, Pb, Ca) from older rocks, and carried them in solution. On a local-scale, this fluid has exploited areas of weakness in the form of fractures, less consolidated conglomeratic material and crosscutting veins. Manganese and iron has been remobilized on a local scale - producing secondary textures and partitioning into phases such as Mn-rich calcite and serandite. Comparisons to other studies in the PMF and KMF have revealed very similar alkali-rich assemblages, bearing many of the same minerals observed in this study - even within more manganiferous deposits. These findings have led to suggestions of a possible regional-scale hydrothermal overprint, which may have imparted a similar geochemical signal over the entire region - with the assistance of faults and unconformities. Of course, proving this is no mean feat, but current work on the source of barium in barite, using Sr isotopes from samples across the region may shed light on the source of at least one key element of these deposits.
- Full Text:
Gaining cyber security insight through an analysis of open source intelligence data: an East African case study
- Authors: Chindipha, Stones Dalitso
- Date: 2018
- Subjects: Open source intelligence -- Africa, East , Computer security -- Africa, East , Computer networks -- Security measures -- Africa, East , Denial of service attacks -- Africa, East , Sentient Hvper-Optimised Data Access Network (SHODAN) , Internet Background Radiation (IBR)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60618 , vital:27805
- Description: With each passing year the number of Internet users and connected devices grows, and this is particularly so in Africa. This growth brings with it an increase in the prevalence cyber-attacks. Looking at the current state of affairs, cybersecurity incidents are more likely to increase in African countries mainly due to the increased prevalence and affordability of broadband connectivity which is coupled with lack of online security awareness. The adoption of mobile banking has aggravated the situation making the continent more attractive to hackers who bank on the malpractices of users. Using Open Source Intelligence (OSINT) data sources like Sentient Hvper-Optimised Data Access Network (SHODAN) and Internet Background Radiation (IBR), this research explores the prevalence of vulnerabilities and their accessibility to evber threat actors. The research focuses on the East African Community (EAC) comprising of Tanzania, Kenya, Malawi, and Uganda, An IBR data set collected by a Rhodes University network telescope spanning over 72 months was used in this research, along with two snapshot period of data from the SHODAN project. The findings shows that there is a significant risk to systems within the EAC, particularly using the SHODAN data. The MITRE CVSS threat scoring system was applied to this research using FREAK and Heartbleed as sample vulnerabilities identified in EAC, When looking at IBR, the research has shown that attackers can use either destination ports or IP source addresses to perform an attack which if not attended to may be reused yearly until later on move to the allocated IP address space once it starts making random probes. The moment it finds one vulnerable client on the network it spreads throughout like a worm, DDoS is one the attacks that can be generated from IBR, Since the SHODAN dataset had two collection points, the study has shown the changes that have occurred in Malawi and Tanzania for a period of 14 months by using three variables i.e, device type, operating systems, and ports. The research has also identified vulnerable devices in all the four countries. Apart from that, the study identified operating systems, products, OpenSSL, ports and ISPs as some of the variables that can be used to identify vulnerabilities in systems. In the ease of OpenSSL and products, this research went further by identifying the type of attack that can occur and its associated CVE-ID.
- Full Text:
- Authors: Chindipha, Stones Dalitso
- Date: 2018
- Subjects: Open source intelligence -- Africa, East , Computer security -- Africa, East , Computer networks -- Security measures -- Africa, East , Denial of service attacks -- Africa, East , Sentient Hvper-Optimised Data Access Network (SHODAN) , Internet Background Radiation (IBR)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60618 , vital:27805
- Description: With each passing year the number of Internet users and connected devices grows, and this is particularly so in Africa. This growth brings with it an increase in the prevalence cyber-attacks. Looking at the current state of affairs, cybersecurity incidents are more likely to increase in African countries mainly due to the increased prevalence and affordability of broadband connectivity which is coupled with lack of online security awareness. The adoption of mobile banking has aggravated the situation making the continent more attractive to hackers who bank on the malpractices of users. Using Open Source Intelligence (OSINT) data sources like Sentient Hvper-Optimised Data Access Network (SHODAN) and Internet Background Radiation (IBR), this research explores the prevalence of vulnerabilities and their accessibility to evber threat actors. The research focuses on the East African Community (EAC) comprising of Tanzania, Kenya, Malawi, and Uganda, An IBR data set collected by a Rhodes University network telescope spanning over 72 months was used in this research, along with two snapshot period of data from the SHODAN project. The findings shows that there is a significant risk to systems within the EAC, particularly using the SHODAN data. The MITRE CVSS threat scoring system was applied to this research using FREAK and Heartbleed as sample vulnerabilities identified in EAC, When looking at IBR, the research has shown that attackers can use either destination ports or IP source addresses to perform an attack which if not attended to may be reused yearly until later on move to the allocated IP address space once it starts making random probes. The moment it finds one vulnerable client on the network it spreads throughout like a worm, DDoS is one the attacks that can be generated from IBR, Since the SHODAN dataset had two collection points, the study has shown the changes that have occurred in Malawi and Tanzania for a period of 14 months by using three variables i.e, device type, operating systems, and ports. The research has also identified vulnerable devices in all the four countries. Apart from that, the study identified operating systems, products, OpenSSL, ports and ISPs as some of the variables that can be used to identify vulnerabilities in systems. In the ease of OpenSSL and products, this research went further by identifying the type of attack that can occur and its associated CVE-ID.
- Full Text:
Understanding the extension capacity needs of the CapeNature Stewardship Programme in the Western Cape Province of South Africa
- Coetzee, Johannes Christiaan
- Authors: Coetzee, Johannes Christiaan
- Date: 2018
- Subjects: Conservation projects (Natural resources) , Psychometrics , Adaptive natural resource management , Biodiversity conservation , CapeNature Stewardship Programme
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63220 , vital:28383
- Description: There is an increasing call for conservation programmes to provide sound evidence of effectiveness, and employing empirical evaluations can assist in the transition to evidence-based conservation practices. The objectives of this research were to develop a logic model for the CapeNature Stewardship Programme which would articulate the programme's theory of operation with respect to its Stewardship Programme landholders. The second major objective was to develop psychometric instruments for assessing the motivations and satisfactions of the programme's stewardship landholders. Both objectives included the aim to provide robust and repeatable instruments for exploring landholder's psychology, and developing a programme's theory of operation to understand the programme and improve with understanding the needs of the landowners. In this regard the processes and methodologies employed represent a major component of this research. A mixed methods approach was utilized, including stakeholder and volunteer surveys, conducted via mailing hardcopies and the internet, together with three focus groups held with the programme's management, extension staff and the stewardship landholders. Analysis of the data thus collected included both qualitative and quantitative approaches, specifically coding and content analysis, together with statistical tests of internal consistency, factor analysis and doubling correspondence analysis. Robust indices for example validity and internal consistency were developed for assessing landholder’s satisfaction with extension and level of satisfaction with the stewardship programme (Babbie 2007). These indices revealed that landholders in the Stewardship Programme are not satisfied with the programme, and exhibit behaviours suggesting they act as advocates for the programme. Demographic data and additional information provided further insights into the programme. The development of a method for articulating the programme's theory of operation is represented, together with four logic models which graphically illustrate this theory. This process and theory allowed for recommendations to be provided for the programme's improvement. A platform for adaptive management and further evaluations of this, and similar programmes, represents a major outcome of this research, understanding the extension capacity needs for the conservation of biodiversity in the CapeNature Stewardship Programme to function as a model for improving the implementation of the programme across the Western Cape, South Africa. This research feeds into an evaluation of CapeNature’s Biodiveristy Stewardship programme and demonstrates the importance of incorporating psychology into conservation interventions.
- Full Text:
- Authors: Coetzee, Johannes Christiaan
- Date: 2018
- Subjects: Conservation projects (Natural resources) , Psychometrics , Adaptive natural resource management , Biodiversity conservation , CapeNature Stewardship Programme
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63220 , vital:28383
- Description: There is an increasing call for conservation programmes to provide sound evidence of effectiveness, and employing empirical evaluations can assist in the transition to evidence-based conservation practices. The objectives of this research were to develop a logic model for the CapeNature Stewardship Programme which would articulate the programme's theory of operation with respect to its Stewardship Programme landholders. The second major objective was to develop psychometric instruments for assessing the motivations and satisfactions of the programme's stewardship landholders. Both objectives included the aim to provide robust and repeatable instruments for exploring landholder's psychology, and developing a programme's theory of operation to understand the programme and improve with understanding the needs of the landowners. In this regard the processes and methodologies employed represent a major component of this research. A mixed methods approach was utilized, including stakeholder and volunteer surveys, conducted via mailing hardcopies and the internet, together with three focus groups held with the programme's management, extension staff and the stewardship landholders. Analysis of the data thus collected included both qualitative and quantitative approaches, specifically coding and content analysis, together with statistical tests of internal consistency, factor analysis and doubling correspondence analysis. Robust indices for example validity and internal consistency were developed for assessing landholder’s satisfaction with extension and level of satisfaction with the stewardship programme (Babbie 2007). These indices revealed that landholders in the Stewardship Programme are not satisfied with the programme, and exhibit behaviours suggesting they act as advocates for the programme. Demographic data and additional information provided further insights into the programme. The development of a method for articulating the programme's theory of operation is represented, together with four logic models which graphically illustrate this theory. This process and theory allowed for recommendations to be provided for the programme's improvement. A platform for adaptive management and further evaluations of this, and similar programmes, represents a major outcome of this research, understanding the extension capacity needs for the conservation of biodiversity in the CapeNature Stewardship Programme to function as a model for improving the implementation of the programme across the Western Cape, South Africa. This research feeds into an evaluation of CapeNature’s Biodiveristy Stewardship programme and demonstrates the importance of incorporating psychology into conservation interventions.
- Full Text:
Assessment of the long-term response to rehabilitation of two wetlands in KwaZulu-Natal, South Africa
- Authors: Cowden, Craig
- Date: 2018
- Subjects: Wetlands -- South Africa -- KwaZulu-Natal Wetland restoration -- South Africa -- KwaZulu-Natal Wetland management -- South Africa -- KwaZulu-Natal Wetland conservation -- South Africa -- KwaZulu-Natal Wetland ecology -- South Africa -- KwaZulu-Natal Ecosystem management -- South Africa -- KwaZulu-Natal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60606 , vital:27802
- Description: Assessing the outputs and outcomes of wetland rehabilitation activities is recognised by the 'Working for Wetlands' programme in South Africa as important, but to date has been limited. An assessment of the ecological outcomes and the structural outputs of the Working for Wetlands rehabilitation implemented in the Killarney and Kruisfontein wetlands, KwaZulu-Natal, in 2005 was undertaken. The assessment of outcomes included an evaluation of the changes in terms of ecological integrity and the supply of ecosystem services, using WET-Health and WET- EcoServices assessment techniques respectively, and vegetation composition. Improvements in hydrological and geomorphic integrity were recorded in both wetlands, resulting in improved ecosystem services delivery. However, investigation of vegetation composition using the Wetland Index Value and Floristic Quality Assessment Index showed that, seven years after rehabilitation, KiNamey's vegetation composition had improved, but Kruisfontein's vegetation was still largely dominated by pioneer species and appeared to be stable, but in a severely transformed state. The response of these wetlands has shown that sites for rehabilitation should be screened before work begins, and wetlands requiring intensive management of vegetation recovery should be assessed in terms of the objectives and the anticipated benefits of the project. The assessment of the outputs included an evaluation of structural integrity, survival and cost- effectiveness. Limited issues, mostly relating to deviations from the designs during construction, were identified with regards to the structural outputs at each of the wetlands. However, the spreader canals at both Killarney and Kruisfontein wetlands were not functioning as intended and concentrated flows from the spreader canals were evident in both wetlands. The use of spreader canals should therefore be carefully planned and implemented for future wetland rehabilitation projects. Consideration of ZAR per hectare equivalent re-instated/secured provided a useful initial means of determining the cost-effectiveness of the wetland rehabilitation. However, additional factors need to be considered, such as, the nature of the rehabilitation activities, the type and size of the problem being addressed, rehabilitation of priority wetlands, limitations imposed by funders, and risks that need to be addressed by the rehabilitation strategy. Furthermore, the evaluation of the Killarney and Kruisfontein wetlands highlighted the need to revise the Water Research Commission's Wetland Management Series, especially those documents or guidelines relating to rehabilitation planning (WET-RehabPlan), interventions (WET-RehabMethods), and monitoring and evaluation (WET-RehabEvaluate).
- Full Text:
- Authors: Cowden, Craig
- Date: 2018
- Subjects: Wetlands -- South Africa -- KwaZulu-Natal Wetland restoration -- South Africa -- KwaZulu-Natal Wetland management -- South Africa -- KwaZulu-Natal Wetland conservation -- South Africa -- KwaZulu-Natal Wetland ecology -- South Africa -- KwaZulu-Natal Ecosystem management -- South Africa -- KwaZulu-Natal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60606 , vital:27802
- Description: Assessing the outputs and outcomes of wetland rehabilitation activities is recognised by the 'Working for Wetlands' programme in South Africa as important, but to date has been limited. An assessment of the ecological outcomes and the structural outputs of the Working for Wetlands rehabilitation implemented in the Killarney and Kruisfontein wetlands, KwaZulu-Natal, in 2005 was undertaken. The assessment of outcomes included an evaluation of the changes in terms of ecological integrity and the supply of ecosystem services, using WET-Health and WET- EcoServices assessment techniques respectively, and vegetation composition. Improvements in hydrological and geomorphic integrity were recorded in both wetlands, resulting in improved ecosystem services delivery. However, investigation of vegetation composition using the Wetland Index Value and Floristic Quality Assessment Index showed that, seven years after rehabilitation, KiNamey's vegetation composition had improved, but Kruisfontein's vegetation was still largely dominated by pioneer species and appeared to be stable, but in a severely transformed state. The response of these wetlands has shown that sites for rehabilitation should be screened before work begins, and wetlands requiring intensive management of vegetation recovery should be assessed in terms of the objectives and the anticipated benefits of the project. The assessment of the outputs included an evaluation of structural integrity, survival and cost- effectiveness. Limited issues, mostly relating to deviations from the designs during construction, were identified with regards to the structural outputs at each of the wetlands. However, the spreader canals at both Killarney and Kruisfontein wetlands were not functioning as intended and concentrated flows from the spreader canals were evident in both wetlands. The use of spreader canals should therefore be carefully planned and implemented for future wetland rehabilitation projects. Consideration of ZAR per hectare equivalent re-instated/secured provided a useful initial means of determining the cost-effectiveness of the wetland rehabilitation. However, additional factors need to be considered, such as, the nature of the rehabilitation activities, the type and size of the problem being addressed, rehabilitation of priority wetlands, limitations imposed by funders, and risks that need to be addressed by the rehabilitation strategy. Furthermore, the evaluation of the Killarney and Kruisfontein wetlands highlighted the need to revise the Water Research Commission's Wetland Management Series, especially those documents or guidelines relating to rehabilitation planning (WET-RehabPlan), interventions (WET-RehabMethods), and monitoring and evaluation (WET-RehabEvaluate).
- Full Text:
Factors influencing estuarine and coastal connectivity of an estuarine-dependent fishery species, Pomadasys commersonnii (Haemulidae)
- Authors: Dames, Michael Henri
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62307 , vital:28153
- Description: Expected release date-April 2019
- Full Text:
- Authors: Dames, Michael Henri
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62307 , vital:28153
- Description: Expected release date-April 2019
- Full Text:
In silico study of Plasmodium 1-deoxy-dxylulose 5-phosphate reductoisomerase (DXR) for identification of novel inhibitors from SANCDB
- Authors: Diallo, Bakary N'tji
- Date: 2018
- Subjects: Plasmodium 1-deoxy-dxylulose 5-phosphate reductoisomerase , Isoprenoids , Plasmodium , Antimalarials , Malaria -- Chemotherapy , Molecules -- Models , Molecular dynamics , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64012 , vital:28523
- Description: Malaria remains a major health concern with a complex parasite constantly developing resistance to the different drugs introduced to treat it, threatening the efficacy of the current ACT treatment recommended by WHO (World Health Organization). Different antimalarial compounds with different mechanisms of action are ideal as this decreases chances of resistance occurring. Inhibiting DXR and consequently the MEP pathway is a good strategy to find a new antimalarial with a novel mode of action. From literature, all the enzymes of the MEP pathway have also been shown to be indispensable for the synthesis of isoprenoids. They have been validated as drug targets and the X-ray structure of each of the enzymes has been solved. DXR is a protein which catalyses the second step of the MEP pathway. There are currently 255 DXR inhibitors in the Binding Database (accessed November 2017) generally based on the fosmidomycin structural scaffold and thus often showing poor drug likeness properties. This study aims to research new DXR inhibitors using in silico techniques. We analysed the protein sequence and built 3D models in close and open conformations for the different Plasmodium sequences. Then SANCDB compounds were screened to identify new potential DXR inhibitors with new chemical scaffolds. Finally, the identified hits were submitted to molecular dynamics studies, preceded by a parameterization of the manganese atom in the protein active site.
- Full Text:
- Authors: Diallo, Bakary N'tji
- Date: 2018
- Subjects: Plasmodium 1-deoxy-dxylulose 5-phosphate reductoisomerase , Isoprenoids , Plasmodium , Antimalarials , Malaria -- Chemotherapy , Molecules -- Models , Molecular dynamics , South African Natural Compounds Database
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64012 , vital:28523
- Description: Malaria remains a major health concern with a complex parasite constantly developing resistance to the different drugs introduced to treat it, threatening the efficacy of the current ACT treatment recommended by WHO (World Health Organization). Different antimalarial compounds with different mechanisms of action are ideal as this decreases chances of resistance occurring. Inhibiting DXR and consequently the MEP pathway is a good strategy to find a new antimalarial with a novel mode of action. From literature, all the enzymes of the MEP pathway have also been shown to be indispensable for the synthesis of isoprenoids. They have been validated as drug targets and the X-ray structure of each of the enzymes has been solved. DXR is a protein which catalyses the second step of the MEP pathway. There are currently 255 DXR inhibitors in the Binding Database (accessed November 2017) generally based on the fosmidomycin structural scaffold and thus often showing poor drug likeness properties. This study aims to research new DXR inhibitors using in silico techniques. We analysed the protein sequence and built 3D models in close and open conformations for the different Plasmodium sequences. Then SANCDB compounds were screened to identify new potential DXR inhibitors with new chemical scaffolds. Finally, the identified hits were submitted to molecular dynamics studies, preceded by a parameterization of the manganese atom in the protein active site.
- Full Text:
The role of ecological processes in structuring reef fish communities in the Agulhas Ecoregion, South Africa
- Authors: Dyer, Alexander
- Date: 2018
- Subjects: Reef fishes -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Ecology -- South Africa -- Agulhas, Cape (Cape) , Marine biodiversity -- South Africa -- Agulhas, Cape (Cape) , Biotic communities -- South Africa -- Agulhas, Cape (Cape) , Sparidae -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Size -- South Africa -- Agulhas, Cape (Cape) , Baited remote underwater stereo-video systems (stereo-BRUVs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63899 , vital:28504
- Description: Local, niche-based processes, which arise from the interplay between biotic interactions and abiotic constraints are considered to be important regulators of community structure. However, it is increasingly recognised that patterns of diversity can also be strongly influenced by dispersal-driven processes. While empirical research on the diversity of coral reef fishes on shallow tropical reefs has contributed greatly to the development of general concepts in ecology, there have been considerably fewer studies on the processes which shape the diversity of fish communities on shallow (10 - 30 m) and deep (30 - 75 m) rocky reefs. Consequently, it is less clear at which spatial scales niche partitioning and dispersal limitation contribute most strongly to the structure of reef-associated fish communities within rocky reef ecosystems. To address this caveat, research was conducted at four rocky reef complexes within the warm-temperate Agulhas Ecoregion, South Africa. The diversity of reef-associated fishes was sampled by baited remote underwater stereo-video systems (stereo-BRUVs) to incorporate the range of heterogeneous reef habitat in Tsitsikamma National Park Marine Protected Area (TNP MPA) and Algoa Bay (AB). To examine how niche-based and dispersal-driven processes influence patterns of diversity among species within the dominant family of resident fishes, the sparids (Sparidae), components of diversity were quantified at several spatial scales. Turnover in the number of species which locally co-occurred was found to be largely driven by the limited dispersal of species over hundreds of kilometres. When relative species abundances were taken into account, sparid communities were characterised by higher than expected rates of compositional turnover among local habitat patches separated by hundreds to thousands of metres of contiguous reef. Patterns of compositional turnover were associated with the spatial aggregation of conspecifics, particularly at scales which facilitate the post-settlement dispersal of fishes. Niche-based segregation of species along the depth gradient was found to be the primary driver of compositional turnover among both protected and exploited communities. However, spatial structuring within reefs, which was independent of variation in the environment, suggests that compositional differences among communities are also influenced by the limited post-settlement dispersal of resident fishes to adjacent areas during their ontogeny. Together, the results suggest that the diversity of reef-associated sparids is likely to depend both on an adequate diversity of suitable reef habitat and a sufficient degree of spatial connectivity to facilitate ontogenetic habitat shifts. Taxon-based descriptors of diversity do not adequately account for ecological difference among conspecifics within size-structured populations. To test whether differences in body size facilitated coexistence among sparid fishes, the number of species which coexisted at the local scale was related to variation in the size structure of communities. In communities which have been historically protected from fishing, local coexistence between a greater number of species was promoted by reduced levels of intraspecific variation in size of fishes. This suggests that, among species with similar trophic requirements, further niche segregation along a prey-size and body-size gradient is likely to mitigate the direct impacts of competition for shared food resources. Among exploited communities, size structure did not influence the number of species which coexisted at the local scale. This finding suggests that fishing-induced mortality of larger-bodied fishes is likely to remove some of the constraints to colonisation which arise from asymmetries in competitive fitness between small and large-bodied fishes. Together, these results highlight the importance of post-settlement processes and population size structure to the maintenance of reef-associated fish diversity within contiguous rocky reef habitats.
- Full Text:
- Authors: Dyer, Alexander
- Date: 2018
- Subjects: Reef fishes -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Ecology -- South Africa -- Agulhas, Cape (Cape) , Marine biodiversity -- South Africa -- Agulhas, Cape (Cape) , Biotic communities -- South Africa -- Agulhas, Cape (Cape) , Sparidae -- South Africa -- Agulhas, Cape (Cape) , Reef fishes -- Size -- South Africa -- Agulhas, Cape (Cape) , Baited remote underwater stereo-video systems (stereo-BRUVs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63899 , vital:28504
- Description: Local, niche-based processes, which arise from the interplay between biotic interactions and abiotic constraints are considered to be important regulators of community structure. However, it is increasingly recognised that patterns of diversity can also be strongly influenced by dispersal-driven processes. While empirical research on the diversity of coral reef fishes on shallow tropical reefs has contributed greatly to the development of general concepts in ecology, there have been considerably fewer studies on the processes which shape the diversity of fish communities on shallow (10 - 30 m) and deep (30 - 75 m) rocky reefs. Consequently, it is less clear at which spatial scales niche partitioning and dispersal limitation contribute most strongly to the structure of reef-associated fish communities within rocky reef ecosystems. To address this caveat, research was conducted at four rocky reef complexes within the warm-temperate Agulhas Ecoregion, South Africa. The diversity of reef-associated fishes was sampled by baited remote underwater stereo-video systems (stereo-BRUVs) to incorporate the range of heterogeneous reef habitat in Tsitsikamma National Park Marine Protected Area (TNP MPA) and Algoa Bay (AB). To examine how niche-based and dispersal-driven processes influence patterns of diversity among species within the dominant family of resident fishes, the sparids (Sparidae), components of diversity were quantified at several spatial scales. Turnover in the number of species which locally co-occurred was found to be largely driven by the limited dispersal of species over hundreds of kilometres. When relative species abundances were taken into account, sparid communities were characterised by higher than expected rates of compositional turnover among local habitat patches separated by hundreds to thousands of metres of contiguous reef. Patterns of compositional turnover were associated with the spatial aggregation of conspecifics, particularly at scales which facilitate the post-settlement dispersal of fishes. Niche-based segregation of species along the depth gradient was found to be the primary driver of compositional turnover among both protected and exploited communities. However, spatial structuring within reefs, which was independent of variation in the environment, suggests that compositional differences among communities are also influenced by the limited post-settlement dispersal of resident fishes to adjacent areas during their ontogeny. Together, the results suggest that the diversity of reef-associated sparids is likely to depend both on an adequate diversity of suitable reef habitat and a sufficient degree of spatial connectivity to facilitate ontogenetic habitat shifts. Taxon-based descriptors of diversity do not adequately account for ecological difference among conspecifics within size-structured populations. To test whether differences in body size facilitated coexistence among sparid fishes, the number of species which coexisted at the local scale was related to variation in the size structure of communities. In communities which have been historically protected from fishing, local coexistence between a greater number of species was promoted by reduced levels of intraspecific variation in size of fishes. This suggests that, among species with similar trophic requirements, further niche segregation along a prey-size and body-size gradient is likely to mitigate the direct impacts of competition for shared food resources. Among exploited communities, size structure did not influence the number of species which coexisted at the local scale. This finding suggests that fishing-induced mortality of larger-bodied fishes is likely to remove some of the constraints to colonisation which arise from asymmetries in competitive fitness between small and large-bodied fishes. Together, these results highlight the importance of post-settlement processes and population size structure to the maintenance of reef-associated fish diversity within contiguous rocky reef habitats.
- Full Text:
Health and fitness of young, healthy adult females and the effect of an eight week pilates intervention
- Authors: Eaton, Lara Lee
- Date: 2018
- Subjects: Physical fitness for women -- South Africa -- Makhanda , Pilates method , Exercise for women -- South Africa -- Makhanda , Exercise -- Health aspects -- South Africa -- Makhanda , Exercise -- Physiological aspects -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58267 , vital:27112
- Description: Purpose: The first phase of this study aimed to investigate the health and fitness status of young adult females in the local community. The second phase of this study investigated the impact of an eight week progressive Pilates intervention on selected health and fitness parameters in this cohort. Methods: Healthy young adult females aged 18-26 years (n=96), from the local community, partook in once-off tests including anthropometric measures (stature, body mass, Body Mass Index and waist circumference) as well as fitness parameters including balance, flexibility, muscular strength and endurance, and lastly lumbo-pelvic stability. Health measures investigated included blood pressure and spirometry. Where possible, results were compared to those of similar populations from national surveys or published normative data. Sedentary volunteers from this cohort were then randomised into a Pilates Exercise (PEx, n=12) or an inactive Control (Con, n=11) group, with their results from Phase 1 serving as baseline measures. Pilates classes were held twice weekly (60 minutes per session). All the measures from phase 1 were repeated at weeks 4 and 8. An additional intervention test included Transversus abdominis recruitment. Participants maintained habitual dietary intake and energy expenditure throughout. Nine PEx group and eight Con group participants completed the intervention. Results: The current sample (phase 1) was found to be healthier than comparative populations from national surveys, and significant differences (p<0.05) were found for all comparisons except Forced Expiratory Volume (FEV1), (p=0.64). Physical activity levels (230 min.week-1) exceeded that of the recommend weekly threshold (150 min.week-1). BMI, waist circumference, blood pressure and spirometry measures were all found to be within suggested healthy normal ranges. Pilates significantly improved lumbo-pelvic stability in the PEx group at weeks 4 (p<0.005) and 8 (p<0.002). Similarly, abdominal (p=0.00, d=1.1), upper limb (p=0.037, d=0.9) and lower limb endurance (p=0.02, d=1.0, between group d=0.73 for PEx) also improved with no changes in the Con group. PEx energy expenditure significantly increased from baseline to weeks 4 (p=0.007, d=10.7) and 8 (p=0.027, d=0.64), however body mass was maintained throughout. Conversely, Minute Ventilation decreased in the PEx cohort (p=0.010, d=0.95) from weeks 4 to 8. The Con group showed significant increases in body mass (p=0.018), leg strength (within-group Cohen’s d=-1.08 between weeks 0-8; d=-2 between weeks 4-8) and dynamic balance (p=0.01, d=-0.5). While no within-group changes were observed, Protein intake was significantly greater (p=0.036, d>0.8 at baseline and week 8) in the PEx group throughout the intervention. Medium between-group effect sizes (d>0.5) were noted for PEx BMI and waist circumference measures at all time points. Further, although not significant, the large within-group effect size (d=-0.84) between baseline and week 8 for PEx systolic blood pressure, suggested the 9 mm Hg was meaningful. The same time period also indicated a large within-group effect size (d=-0.8) for PEx dynamic balance, and a medium Cohen’s d for (d=0.57) PEx static balance. Conclusion: The local population of young adult females was found to be significantly healthier than those of comparable national samples. Further, Pilates participation significantly improved lumbo-pelvic stability and muscular endurance with meaningful changes in systolic blood pressure, and balance in previously sedentary young, adult females. Body mass was also maintained.
- Full Text:
- Authors: Eaton, Lara Lee
- Date: 2018
- Subjects: Physical fitness for women -- South Africa -- Makhanda , Pilates method , Exercise for women -- South Africa -- Makhanda , Exercise -- Health aspects -- South Africa -- Makhanda , Exercise -- Physiological aspects -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58267 , vital:27112
- Description: Purpose: The first phase of this study aimed to investigate the health and fitness status of young adult females in the local community. The second phase of this study investigated the impact of an eight week progressive Pilates intervention on selected health and fitness parameters in this cohort. Methods: Healthy young adult females aged 18-26 years (n=96), from the local community, partook in once-off tests including anthropometric measures (stature, body mass, Body Mass Index and waist circumference) as well as fitness parameters including balance, flexibility, muscular strength and endurance, and lastly lumbo-pelvic stability. Health measures investigated included blood pressure and spirometry. Where possible, results were compared to those of similar populations from national surveys or published normative data. Sedentary volunteers from this cohort were then randomised into a Pilates Exercise (PEx, n=12) or an inactive Control (Con, n=11) group, with their results from Phase 1 serving as baseline measures. Pilates classes were held twice weekly (60 minutes per session). All the measures from phase 1 were repeated at weeks 4 and 8. An additional intervention test included Transversus abdominis recruitment. Participants maintained habitual dietary intake and energy expenditure throughout. Nine PEx group and eight Con group participants completed the intervention. Results: The current sample (phase 1) was found to be healthier than comparative populations from national surveys, and significant differences (p<0.05) were found for all comparisons except Forced Expiratory Volume (FEV1), (p=0.64). Physical activity levels (230 min.week-1) exceeded that of the recommend weekly threshold (150 min.week-1). BMI, waist circumference, blood pressure and spirometry measures were all found to be within suggested healthy normal ranges. Pilates significantly improved lumbo-pelvic stability in the PEx group at weeks 4 (p<0.005) and 8 (p<0.002). Similarly, abdominal (p=0.00, d=1.1), upper limb (p=0.037, d=0.9) and lower limb endurance (p=0.02, d=1.0, between group d=0.73 for PEx) also improved with no changes in the Con group. PEx energy expenditure significantly increased from baseline to weeks 4 (p=0.007, d=10.7) and 8 (p=0.027, d=0.64), however body mass was maintained throughout. Conversely, Minute Ventilation decreased in the PEx cohort (p=0.010, d=0.95) from weeks 4 to 8. The Con group showed significant increases in body mass (p=0.018), leg strength (within-group Cohen’s d=-1.08 between weeks 0-8; d=-2 between weeks 4-8) and dynamic balance (p=0.01, d=-0.5). While no within-group changes were observed, Protein intake was significantly greater (p=0.036, d>0.8 at baseline and week 8) in the PEx group throughout the intervention. Medium between-group effect sizes (d>0.5) were noted for PEx BMI and waist circumference measures at all time points. Further, although not significant, the large within-group effect size (d=-0.84) between baseline and week 8 for PEx systolic blood pressure, suggested the 9 mm Hg was meaningful. The same time period also indicated a large within-group effect size (d=-0.8) for PEx dynamic balance, and a medium Cohen’s d for (d=0.57) PEx static balance. Conclusion: The local population of young adult females was found to be significantly healthier than those of comparable national samples. Further, Pilates participation significantly improved lumbo-pelvic stability and muscular endurance with meaningful changes in systolic blood pressure, and balance in previously sedentary young, adult females. Body mass was also maintained.
- Full Text:
The metabolic physiology of early stage Argyrosomus japonicus with insight into the potential effects of pCO2 induced ocean acidification
- Authors: Edworthy, Carla
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Larvae -- Ecology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/51417 , vital:26094
- Description: Ocean acidification is a phenomenon associated with global change and anthropogenic CO2 emissions that is changing the chemistry of seawater. These changes result in elevated pCO2 and reduced pH in seawater and this is impacting marine organisms in various ways. Marine fishes are considered generally tolerant to conditions of ocean acidification; however, these assumptions are based on juvenile and adult fish tolerance and the larval stages have not been frequently assessed. Furthermore, it has been suggested that temperate species, particularly those with an estuarine association, may be tolerant to variable CO2 and pH. This study used an eco-physiological approach to understand how the early life stages of Argyrosomus japonicus, an estuarine dependent marine fisheries species found in warm-temperate regions, may be impacted by ocean acidification. The metabolic response of early stage larvae (hatching to early juvenile stage) was assessed under conditions of elevated pCO2 and reduced pH in a controlled laboratory setting. Small volume static respirometry was used to determine the oxygen consumption rate of larvae raised in three pCO2 treatments including a low (pCO2 = 327.50 ± 80.07 µatm at pH 8.15), moderate (pCO2 477.40 ± 59.46 µatm at pH 8.03) and high treatment (PCO2 910.20 ± 136.45 µatm at pH 7.78). These treatment levels were relevant to the present (low) and projected conditions of ocean acidification for the years 2050 (moderate) and 2100 (high). Prior to experimentation with ocean acidification treatments, baseline metabolic rates and diurnal variation in oxygen consumption rates in early stage A. japonicus was determined. Distinct ontogenetic structuring of metabolic rates was observed in early stage A. japonicus, with no cyclical fluctuations in metabolic rate occurring during the 24 hour photoperiodic cycle. Pre-flexion larvae showed no metabolic response to ocean acidification treatments; however post-flexion stage larvae showed metabolic depression of standard metabolic rate in the moderate (32.5%) and high (9.5%) pCO2 treatments (P = 0.02). Larvae raised in the high pCO2 treatment also showed high levels of mortality with no individuals surviving past the post-flexion stage. Larvae raised in the moderate pCO2 treatment were unaffected. This study concluded that ocean acidification conditions expected for the end of the century will have significant impacts on the metabolism of early stage A. japonicus, which may result in reduced growth, retardation of skeletal development and ultimately survival as a result of increased mortality. Furthermore, the timing of reduced metabolic scope will significantly impact the recruitment ability of A. japonicus larvae into estuarine habitats. This could ultimately impact the sustainability of A. japonicus populations. Most importantly, this study highlighted the need to consider the combined effect of ontogeny and life-history strategy when assessing the vulnerability of species to ocean acidification.
- Full Text:
- Authors: Edworthy, Carla
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Larvae -- Ecology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/51417 , vital:26094
- Description: Ocean acidification is a phenomenon associated with global change and anthropogenic CO2 emissions that is changing the chemistry of seawater. These changes result in elevated pCO2 and reduced pH in seawater and this is impacting marine organisms in various ways. Marine fishes are considered generally tolerant to conditions of ocean acidification; however, these assumptions are based on juvenile and adult fish tolerance and the larval stages have not been frequently assessed. Furthermore, it has been suggested that temperate species, particularly those with an estuarine association, may be tolerant to variable CO2 and pH. This study used an eco-physiological approach to understand how the early life stages of Argyrosomus japonicus, an estuarine dependent marine fisheries species found in warm-temperate regions, may be impacted by ocean acidification. The metabolic response of early stage larvae (hatching to early juvenile stage) was assessed under conditions of elevated pCO2 and reduced pH in a controlled laboratory setting. Small volume static respirometry was used to determine the oxygen consumption rate of larvae raised in three pCO2 treatments including a low (pCO2 = 327.50 ± 80.07 µatm at pH 8.15), moderate (pCO2 477.40 ± 59.46 µatm at pH 8.03) and high treatment (PCO2 910.20 ± 136.45 µatm at pH 7.78). These treatment levels were relevant to the present (low) and projected conditions of ocean acidification for the years 2050 (moderate) and 2100 (high). Prior to experimentation with ocean acidification treatments, baseline metabolic rates and diurnal variation in oxygen consumption rates in early stage A. japonicus was determined. Distinct ontogenetic structuring of metabolic rates was observed in early stage A. japonicus, with no cyclical fluctuations in metabolic rate occurring during the 24 hour photoperiodic cycle. Pre-flexion larvae showed no metabolic response to ocean acidification treatments; however post-flexion stage larvae showed metabolic depression of standard metabolic rate in the moderate (32.5%) and high (9.5%) pCO2 treatments (P = 0.02). Larvae raised in the high pCO2 treatment also showed high levels of mortality with no individuals surviving past the post-flexion stage. Larvae raised in the moderate pCO2 treatment were unaffected. This study concluded that ocean acidification conditions expected for the end of the century will have significant impacts on the metabolism of early stage A. japonicus, which may result in reduced growth, retardation of skeletal development and ultimately survival as a result of increased mortality. Furthermore, the timing of reduced metabolic scope will significantly impact the recruitment ability of A. japonicus larvae into estuarine habitats. This could ultimately impact the sustainability of A. japonicus populations. Most importantly, this study highlighted the need to consider the combined effect of ontogeny and life-history strategy when assessing the vulnerability of species to ocean acidification.
- Full Text:
Aquatic habitat shift assessment in a groundwater-fed semi-arid stream: an investigation into the response of Karoo hydroecology to system variability
- Authors: Ellis, Natalie
- Date: 2018
- Subjects: Aquatic habitats -- South Africa -- Karoo , Arid regions -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo , Stream ecology -- South Africa -- Karoo
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61882 , vital:28072
- Description: From introduction: The subject of biological response to changes in aquatic habitat is one which has been well explored in many regions of the world. Examples include work in south east Spain by Mellado Diaz et al. (2008) and Oliva-Paterna et al. (2003), in western United States of America by Hauer and Lorang (2004), and in West Germany by Meyer et al. (2003). Similarly, a number of studies have been conducted in semi-arid regions, exploring elements such as erosion, climate, lithology and landscape formations (e.g. Boardman et al., 2013; Le Maitre et al., 2007; Meyer et al., 2003). However, apart from the study by Uys (1997), and Uys and O’Keeffe (1997), there is a noticeable lack of literature on aquatic habitat shifts in semi-arid stream systems, despite these systems being recognised for their high natural variability. This study provides a base-level approach to conducting habitat shift assessments in a semi-arid stream system and monitoring the hydroecological responses to system variability.
- Full Text:
- Authors: Ellis, Natalie
- Date: 2018
- Subjects: Aquatic habitats -- South Africa -- Karoo , Arid regions -- South Africa -- Karoo , Biotic communities -- South Africa -- Karoo , Stream ecology -- South Africa -- Karoo
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61882 , vital:28072
- Description: From introduction: The subject of biological response to changes in aquatic habitat is one which has been well explored in many regions of the world. Examples include work in south east Spain by Mellado Diaz et al. (2008) and Oliva-Paterna et al. (2003), in western United States of America by Hauer and Lorang (2004), and in West Germany by Meyer et al. (2003). Similarly, a number of studies have been conducted in semi-arid regions, exploring elements such as erosion, climate, lithology and landscape formations (e.g. Boardman et al., 2013; Le Maitre et al., 2007; Meyer et al., 2003). However, apart from the study by Uys (1997), and Uys and O’Keeffe (1997), there is a noticeable lack of literature on aquatic habitat shifts in semi-arid stream systems, despite these systems being recognised for their high natural variability. This study provides a base-level approach to conducting habitat shift assessments in a semi-arid stream system and monitoring the hydroecological responses to system variability.
- Full Text:
Effects of CO2-induced ocean acidification on the early development, growth, survival and skeletogenesis of the estuarine-dependant sciaenid Argyrosomus japonicus
- Authors: Erasmus, Bernard
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Ecology , Argyrosomus -- Physiology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60585 , vital:27799
- Description: Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
- Full Text:
- Authors: Erasmus, Bernard
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Ecology , Argyrosomus -- Physiology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60585 , vital:27799
- Description: Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
- Full Text:
Discovery and validation of a CD4 binding aptamer through Crossover SELEX towards the preliminary development of a point-of-care aptasensor for rapid CD4+ T-cell counting
- Authors: Fellows, Tamika
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63527 , vital:28431
- Description: Expected release date-April 2020
- Full Text:
- Authors: Fellows, Tamika
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63527 , vital:28431
- Description: Expected release date-April 2020
- Full Text:
Influence of knowledge of the end-point on pacing during a 2000m rowing time trial
- Authors: Ferreira, Dean
- Date: 2018
- Subjects: Rowing -- Training , Rowing -- Coaching , Endurance sports -- Training , Rowers -- Ability testing , Rowing -- Training -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61636 , vital:28044
- Description: Introduction: A typical 2000 m rowing race requires maximal force production over six to eight minutes. Optimal distribution of energetic resources during such a race is vital for optimal performance. There is little research examining the pacing strategies employed by rowers, particularly at the sub-elite level. Aim: The purpose of this investigation was to determine the influence of knowledge of the end-point on pacing during a 2000 m rowing time trial. Methods: Eleven male rowers from a university rowing club volunteered to partake in the study. Each participant completed three experimental trials on an indoor rowing ergometer, each 2000 m. The only difference between the trials was the nature of the information provided beforehand. At the start of the control trial, participants were correctly informed about the distance to be covered. Participants were not informed of the distance to be completed in the unknown trial. For the deceptive trial, participants were told 1000 m would be completed, but when this distance was reached, they were told to continue for another 1000 m. During each trial muscle activity, power output, heart rate, performance time and perceptions of effort were measured.Results: The control trial was significantly (p<0.05) faster than both the unknown and deceptive trials, however the deceptive trial was the fastest of all trials at the 1000 m distance. The unknown trial was slowest at 1000 m and at 2000 m. Muscle activity, RPE, heart rate and power output were significantly (p<0.05) lower in the unknown trial compared to the control and deceptive trial. The control trial exhibited a reverse J-shape pacing profile. The deceptive trial revealed a significant (p<0.05) reduction in performance time, heart rate, power output and muscle activity after the 1000 m interval. The first 500 m interval had the fastest performance and highest power output in all trials. In all trials, RPE was highest at the end of the 2000 m, the greatest reading being obtained at the end of the control trial. During the first 1000 m of the deceptive trial, the dependant variables were similar to those in the control trial. Once the deception was revealed, there was a significant (p<0.05) reduction in the muscle activity, heart rate and power output. Conclusion: The results of this study indicate that accurate end-point information is crucial to the development of an optimal pacing strategy, and ultimately to successful performance. Rowers tend to adopt the reverse J-shape pacing profile most often due to the tactical and physiological benefits offered by this strategy. Unknown or inaccurate end-point information resulted in performance decrements due to the uncertainty associated with the exercise bout.
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- Authors: Ferreira, Dean
- Date: 2018
- Subjects: Rowing -- Training , Rowing -- Coaching , Endurance sports -- Training , Rowers -- Ability testing , Rowing -- Training -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61636 , vital:28044
- Description: Introduction: A typical 2000 m rowing race requires maximal force production over six to eight minutes. Optimal distribution of energetic resources during such a race is vital for optimal performance. There is little research examining the pacing strategies employed by rowers, particularly at the sub-elite level. Aim: The purpose of this investigation was to determine the influence of knowledge of the end-point on pacing during a 2000 m rowing time trial. Methods: Eleven male rowers from a university rowing club volunteered to partake in the study. Each participant completed three experimental trials on an indoor rowing ergometer, each 2000 m. The only difference between the trials was the nature of the information provided beforehand. At the start of the control trial, participants were correctly informed about the distance to be covered. Participants were not informed of the distance to be completed in the unknown trial. For the deceptive trial, participants were told 1000 m would be completed, but when this distance was reached, they were told to continue for another 1000 m. During each trial muscle activity, power output, heart rate, performance time and perceptions of effort were measured.Results: The control trial was significantly (p<0.05) faster than both the unknown and deceptive trials, however the deceptive trial was the fastest of all trials at the 1000 m distance. The unknown trial was slowest at 1000 m and at 2000 m. Muscle activity, RPE, heart rate and power output were significantly (p<0.05) lower in the unknown trial compared to the control and deceptive trial. The control trial exhibited a reverse J-shape pacing profile. The deceptive trial revealed a significant (p<0.05) reduction in performance time, heart rate, power output and muscle activity after the 1000 m interval. The first 500 m interval had the fastest performance and highest power output in all trials. In all trials, RPE was highest at the end of the 2000 m, the greatest reading being obtained at the end of the control trial. During the first 1000 m of the deceptive trial, the dependant variables were similar to those in the control trial. Once the deception was revealed, there was a significant (p<0.05) reduction in the muscle activity, heart rate and power output. Conclusion: The results of this study indicate that accurate end-point information is crucial to the development of an optimal pacing strategy, and ultimately to successful performance. Rowers tend to adopt the reverse J-shape pacing profile most often due to the tactical and physiological benefits offered by this strategy. Unknown or inaccurate end-point information resulted in performance decrements due to the uncertainty associated with the exercise bout.
- Full Text: