Development of a distributed optical fiber sensor for geological applications
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: James, Jena
- Date: 2022-04
- Subjects: Polymers--Optical properties -- South Africa , Detectors—Materials
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56156 , vital:55973
- Description: The purpose of the study was to develop a distributed optical fiber acoustic sensor for monitoring ground subsidence before collapse sinkholes form causing costly damage on infrastructure. Costs in excess of R1.3 billion have been incurred while dealing with sinkhole related measures in South Africa. Monitoring sinkholes and the presence of an early warning alert system can drastically reduce the impact, risk and cost caused by sudden ground collapse. A related goal was to construct a reliable collapse alert early warning system to facilitate disaster preparedness and avoid further damage from accidents. This was achieved by developing a spectroscopic shift monitoring algorithm which analysed changes in the subsurface vibration modes using ambient noise signals. For the first time to our knowledge, an optic fiber sensor with an early warning alarm, using ambient noise vibrations to detect and monitor sinkholes was developed at NMU. A polarisation-based, interferometric optical fiber seismic sensor was developed and compared to a commercial geophone. The fiber sensor exhibited superior performance in sensitivity, bandwidth, signal response and recovery times. The sensitivity of the optical fiber sensor was 0.47 rad/Pa surpassing the geophone sensitivity by 9.32%, and the bandwidth of 3.349kHz was 20 times greater for the optical fiber sensor. The fiber sensor was used to measure millisecond events as the impact duration of a bouncing ball was successfully obtained. It was used to detect sinkhole formation in the simulator model, designed. Ground collapse precursors were identified, and early warning alert was achieved using the spectral analysis algorithm, developed. The collapse precursor condition was identified as a functional combination of variations in the peak frequency, bandwidth and peak intensity. A distributed acoustic sensor was built to detect ambient noise induced subsurface signals. Vibrations were located along the 28km length of optical fiber with a relative error of 9.6%. The sensor demonstrated a frequency response range of 212.25Hz, an event distance precision of 224m with time resolution of 1.12µs, and a spatial resolution of 1km. The position of disturbance was measured within 300m of its actual point of 3.21km along the optical fiber. The results showed that distributed optical fiber sensing allows real-time monitoring of the subsurface over extended distances, using ambient noise signals. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2022
- Full Text:
- Date Issued: 2022-04
Effect of pomegranate (Punica granatum L) peel powder meal on growth performance, gut integrity, haemato-biochemical indices, meat, and bone quality of broiler chickens
- Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Akuru, Eunice Amaka https://orcid.org/0000-0002-3093-0247
- Date: 2022-04
- Subjects: Broilers (Chickens) , Meat -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23611 , vital:58218
- Description: The objective of the current study was to investigate the overall response of broiler birds to varying dietary levels of pomegranate (Punica granatum L) peel powder meal (PPPM). A total of 432-day-old Cobb 500 broiler chicks were randomly divided into six experimental groups of four replications with 18 birds per replicate in a completely randomized design (CRD). The birds were fed isonitrogenous and isocaloric experimental diets designated as: T1-control diet with 0percent additives (negative control; NEGCON); T2- control diet supplemented with α-tocopherol acetate at 200g per ton (positive control; POSCON): T3, T4, T5 and T6-control diet supplemented with 2, 4, 6 and 8g/kg PPPM (PPPM2, PPPM4, PPPM6, PPPM8). The phytochemical, nutritional and antioxidant properties of the pomegranate peel powder were determined. Results showed that the South African-grown pomegranate peel (“Wonderful” variety) had rich protein and trace mineral contents. Higher (p < 0.05) antioxidant and hepatic anti-lipid peroxidative activities were recorded in the ethanol and acetone extracts than the water extract, whereas the three extracts had no toxic effects on liver and kidney cells (p > 0.05). The dietary effects of PPPM supplementation on growth performance, digestibility, carcass, and organ weight indices of Cobb 500 birds were determined. The POSCON diet enhanced (p < 0.05) feed conversion ratio (FCR) at week 3. The average final body weight and average daily weight gain were highest (p < 0.05) in birds fed PPPM2 and PPPM4 diets, whereas birds fed PPPM2 diet had enhanced (p < 0.05) FCR and protein efficiency ratio when compared with birds on POSCON. Thigh and breast weights were highest (p < 0.05) in birds on PPPM4 and PPPM8 diets, whereas birds fed PPPM4 diet had enhanced (p < 0.05) nutrient digestibility compared with those on POSCON. The antioxidant status and breast meat quality of Cobb 500 broiler birds fed diets supplemented with PPPM were determined. Meat from birds fed PPPM8 diet had the highest (p < 0.05) thawing loss, while cooking loss was lowest (p < 0.05) in the PPPM2 group. The highest (p < 0.05) ability to scavenge ABTS [(2, 2-azinobis (3ethylbenzothiazoline-6 sulfonic acid))] radical cation (ABTS+) was recorded in the PPPM2 and PPPM4 meat while PPPM8 meat had increased (p < 0.05) catalase activity. The fatty acid composition, oxidative status, and drip loss in breast meat of Cobb 500 broiler birds fed graded levels of PPPM was determined. Meat from birds fed PPPM4 diet had the lowest (p < 0.05) margaric (C17:0) and arachidic (C20:0) acids, while meat from birds fed PPPM8 diet had higher (p < 0.05) levels of eicosadenoic (C20:2, n-6) and arachidonic (AA, 20:4) acids. The POSCON had higher (p < 0.05) ability to reduce TBARS levels in meat on day-1 and day-16 of storage than the NEGCON and PPPM diets, whereas TBARS levels were lowest (p < 0.05) in PPPM6 meat on day-16. The gut pH, histology, haematology, serum-biochemical indices, and bone quality parameters of Cobb 500 broiler birds fed diets supplemented with PPPM was determined. Birds fed POSCON, PPM2 and PPPM4 diets had the lowest (p < 0.05) pH in the duodenum, jejunum, and caecum, whereas duodenal pH values were lowest (p < 0.05) in birds fed PPPM2 and PPPM4 diets compared with birds on NEGCON. Birds fed PPPM4 diet had the highest (p < 0.01) duodenal, jejunal and ileal villi height (VH), and the highest (p < 0.01) VH to crypt depth (CD) ratio in the duodenum, jejunum, and ileum. The lowest (p < 0.05) CD in the duodenum, jejunum and ileum was also recorded in birds fed PPPM4 diet. Birds fed PPPM8 diet had higher (p < 0.05) values for white blood cell count, red blood cell count, haemoglobin concentration and packed cell volume, whereas the lowest (p < 0.05) concentration of serum aspartate transaminase was recorded in birds fed PPPM4 diet. Birds on PPM4 diet had longer (p < 0.05) bones. Bone weight and bone breaking strength were highest (p < 0.05) in birds fed PPPM8 diet. Tibia zinc and iron concentrations increased as the inclusion levels of pomegranate peel powder meal increased. It was concluded that broiler birds require 4 g/kg pomegranate peel powder for enhanced growth performance, nutrient digestibility, gut histology, quality, and antioxidant enzyme activity of meat, whereas 8 g/kg pomegranate peel powder meal supplementation is required for enhanced heamato-biochemical indices, bone quality, fatty acid composition and lipid peroxidative parameters in broiler birds. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Evaluation of antimicrobial combination therapy options for the management of integron-mediated multidrug resistance in enterococcus species and acinetobacter baumannii from aquatic environment in the Eastern Cape Province, South Africa
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Ola, Adeniji Oluwaseun
- Date: 2022-04
- Subjects: Enterococcus , Aquatic biodiversity , Acinetobacter
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27776 , vital:69467
- Description: Infectious diseases caused by multidrug-resistant MDR pathogens, such as Acinetobacter baumannii and Enterococcus spp., is an increasing worldwide problem. For treating these diseases, antibiotics are usually the first choice. But organisms develop resistance as a result of drug abuse, continuous use of antibiotics and release of antibiotics into the environment. These have prompted MDR's development, making even the most active drugs ineffective. Transposons, plasmids and integrons are the most effective mobile genetic elements that promote acquisition and spread of resistance determinants. Integrons carrying various arrays of resistance gene cassettes are principally helpful for epidemiological studies of these disease-causing organisms. Alternative treatments, such as using drugs in combination or with adjuvants and nanoparticles therapy, have been documented. Nanoparticles have the potential requirements for qualifying as antibacterial agents. In addition to their antimicrobial activities, nanoparticles can be used together with antibiotics for more enhanced antimicrobial activity In this study, Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were recovered from the aquatic environment in the Eastern Cape Province, South Africa with a standard microbiological method. Their antibiotic sensitivity testing was carried out using Kirby Bauer disk diffusion and microdilution methods. A high occurrence of class-1 integrons was discovered in MDR A. baumanni, with the internal variable containing aadA1, aadA5 and aadA2 genes, which confer resistance for streptomycin and spectinomycin, aac 6Ib for amikacin/ tobramycin and dfrA17 genes for trimethoprim. Similarly, class1 integron was detected in Enterococcus, without the presence of gene cassette. The checkerboard assay and time-kill assay were used to test for the effect of the combination of the antibiotic. The impact of colistin combined with quinolones (ciprofloxacin) with the Fractional inhibitory concentration index FICs 0.31 indicated synergistic effects against MDR A baumanni. However, when colistin was combined with meropenem and ceftazidime, additive effects with FIC, ranging from 0.52 to 1 were observed. In addition, a combination of gentamicin MIC 4 μgml with vancomycin MIC 256 μgml antibiotics against vancomycin-resistant Enterococcus faecalis showed antibacterial activity. In contrast, the combination of ciprofloxacin 1 μgml with Ampicillin 16 μgml antibiotics against Enterococcus faecalis showed a bacteriostatic effect. The initial inoculum declined by 100 percentage when gentamicin was combined with vancomycin at a concentration of 4 and 128 μgml MIC respectively, for about 2 h following the treatment for MDR E. faecium. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction ERIC PCR analyses of the studied pathogens revealed great genetic diversity, suggesting the various sources of environmental contamination. Silver nanoparticles AgNPs and zinc oxide nanoparticles ZnO NPs were chemically synthesized using a precipitation method and characterized using energy dispersive Xray analysis EDX, scanning electron microscopy SEM, Fourier transforms infrared spectroscopic analysis FTIR and transmission electron microscopy TEM. The characterization results showed the synthesis of 43.37 nm and 21.03 nm nanoparticles of zinc oxide and silver origins, correspondingly, with distinct morphology, as revealed in TEM. The size, stability and functional groups of the nanoparticles produced were revealed using EDX and FTIR. Zinc oxide nanoparticles were cytotoxic against Vero cell lines at the tested concentrations, whereas AgNPs had no cytotoxic effect at lower concentrations. Acinetobacter baumanni, Enterococcus faecium and Enterococcus faecalis were with MIC in the range of 0.0390.078mgml for silver nanoparticles. Zinc oxide nanoparticles were explicitly active against Enterococcus species gram-positive with MIC of 1.25 5 mgml. Both studied nanoparticles exhibited profound synergistic and additive activities against all the investigated MDR pathogens. These findings demonstrate good antibacterial potential of the nanoparticles against drug-resistant strains and open a new arena of antimicrobials for medical treatment. , Thesis (MSc) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Grappling with food and livelihood practices in the context of socio-ecological displacement: The case of 2014 Tokwe-Mukorsi flood victims in Chingwizi, Zimbabwe
- Mudefi, Elmon https://orcid.org/0000-0003-3448-5432
- Authors: Mudefi, Elmon https://orcid.org/0000-0003-3448-5432
- Date: 2022-04
- Subjects: Food security , Households , Natural disasters -- Zimbabwe
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22056 , vital:51979
- Description: This study sought to examine how the socio-ecologically displaced Tokwe-Mukorsi community in southern Zimbabwe grappled with adverse circumstances that threatened to obliterate their age-old food and livelihood practices after five years of being resettled 150km away in Chingwizi. The investigation is done against the backdrop of the dominant narrative on resilience, which often overlooks resilience outcomes associated with specific contextual experiences of socio-ecological disadvantage. The study examined the nature and character of emergent food and livelihood practices in Chingwizi, with a view to establishing how they were impacted by socio-political dynamics encountered vis-à-vis displacement, resettlement and in processes of attempting to recover. The study also examined how local narratives about the new food and livelihood practices in Chingwizi intersect with dominant resilience discourses, especially those related to climate change adaptation, sustainability and food security. A triangulated research design was utilised. It consisted of survey, focus group discussion, in-depth interview, and key informant interview. Qualitative research participants were selected based on their knowledge and experience on food and livelihood practices before and after displacement. This included the displaced flood victims that met this criterion, local leaders, government officials and local opinion leaders. The findings revealed that food and livelihood practices in Chingwizi had deteriorated over the five-year period under investigation. This was reflected in a diminution in livestock herds, crop production, income streams and average household monthly incomes. As a result, food insecurity was very high, and households were forced to rely more on donations. The displaced flood victims, however, adapted to the harsh conditions by engaging in a variety of livelihood alternatives, including food vending, buying and selling, craftwork, small livestock rearing, and migrating to neighbouring South Africa to seek employment opportunities. Nevertheless, efforts to rebuild food and livelihood practices were hampered by socio-political dynamics. This resulted in the loss of key livelihood assets, a situation aggravated by compensational injustice, contestations over land and resources by the host communities, dysfunctional social networks, and victims’ cultural ‘fixations’. The study concludes from these and other findings that achieving transformation in the form of adaptation, food security and sustainability following involuntary displacement and resettlement is more than just a question of resilience, and that displacement and resettlement are complex processes that create invidious dynamism for the stakeholders concerned. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mudefi, Elmon https://orcid.org/0000-0003-3448-5432
- Date: 2022-04
- Subjects: Food security , Households , Natural disasters -- Zimbabwe
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22056 , vital:51979
- Description: This study sought to examine how the socio-ecologically displaced Tokwe-Mukorsi community in southern Zimbabwe grappled with adverse circumstances that threatened to obliterate their age-old food and livelihood practices after five years of being resettled 150km away in Chingwizi. The investigation is done against the backdrop of the dominant narrative on resilience, which often overlooks resilience outcomes associated with specific contextual experiences of socio-ecological disadvantage. The study examined the nature and character of emergent food and livelihood practices in Chingwizi, with a view to establishing how they were impacted by socio-political dynamics encountered vis-à-vis displacement, resettlement and in processes of attempting to recover. The study also examined how local narratives about the new food and livelihood practices in Chingwizi intersect with dominant resilience discourses, especially those related to climate change adaptation, sustainability and food security. A triangulated research design was utilised. It consisted of survey, focus group discussion, in-depth interview, and key informant interview. Qualitative research participants were selected based on their knowledge and experience on food and livelihood practices before and after displacement. This included the displaced flood victims that met this criterion, local leaders, government officials and local opinion leaders. The findings revealed that food and livelihood practices in Chingwizi had deteriorated over the five-year period under investigation. This was reflected in a diminution in livestock herds, crop production, income streams and average household monthly incomes. As a result, food insecurity was very high, and households were forced to rely more on donations. The displaced flood victims, however, adapted to the harsh conditions by engaging in a variety of livelihood alternatives, including food vending, buying and selling, craftwork, small livestock rearing, and migrating to neighbouring South Africa to seek employment opportunities. Nevertheless, efforts to rebuild food and livelihood practices were hampered by socio-political dynamics. This resulted in the loss of key livelihood assets, a situation aggravated by compensational injustice, contestations over land and resources by the host communities, dysfunctional social networks, and victims’ cultural ‘fixations’. The study concludes from these and other findings that achieving transformation in the form of adaptation, food security and sustainability following involuntary displacement and resettlement is more than just a question of resilience, and that displacement and resettlement are complex processes that create invidious dynamism for the stakeholders concerned. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2022
- Full Text:
- Date Issued: 2022-04
HRM digitalisation and value added in the south African workplace
- Authors: Chapano, Munodani
- Date: 2022-04
- Subjects: Personnel management , Human Resources Assessment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57578 , vital:58094
- Description: The main objective of this study was to determine the extent and nature of value that HRM digitalisation can add to the South African workplace. Digitalisation is a product of 4IR, which refers to the process of leveraging and applying 4IR technologies within organisational operations, including HRM, with the aim of optimising business processes. HRM digitalisation refers to the adoption and application of digital HRM technologies of the 4IR in the conduct of HRM practices, policies, activities and transactions to optimise the HRM function. Due to a shortage of studies that shed light on the value contributed by HRM digitalisation in the workplace, a need arises to determine the extent and nature of this value and the strategies needed to unlock this potential in the context of the 4IR. Moreover, in most South African (SA) organisations, there has been a lack of a fully integrated approach to digital HRM. Thus, this study aims at exploring HRM digitalisation and the value it contributes to South African organisations, with the expectation of developing an articulated and integrative HRM digital strategy for South African organisations. This study was accomplished by means of a literature and an empirical study. The literature study provided theoretical information related to challenges and opportunities introduced by the 4IR in the world of work, with specific reference to the South African workplace and which therefore impact HRM and necessitate the need for digitalisation of HRM. In addition, the following were explored: HRM Digital Strategies that could be adopted and add value in the South African workplace; the extent and nature of that value; the challenges probably encountered in doing so and possible means to overcome the challenges. The discussion led to the development of a hypothetical, theoretical model of HRM digitalisation in the South African workplace. The hypothetical model was used as the basis for the development of a measuring instrument used to collect empirical data for this study. The empirical study used the online questionnaire survey as the data collection instrument that measured the extent and nature of value that various HRM Digital Strategies could vii | P a g e add to the South African workplace; perceived value and hard evidence of the impact of HRM digitalisation; and the extent and nature of challenges associated with the Adoption of HRM Digital Strategies across the HR value chain. The online survey questionnaire was administered to HR directors, HR managers, HR practitioners and line managers who worked in the automotive manufacturing industry in the municipalities of Nelson Mandela Bay in Port Elizabeth and Buffalo City in East London in the Eastern Cape Province of South Africa. A non-probability sampling procedure which comprised a combination of purposive and snowball sampling methods was used to select participants for the study (n = 312). The results from the empirical study, computed using Exploratory Factor Analysis (EFA), descriptive statistics and inferential statistics (such as paired-sample t-tests, Pearson’s product moment correlation and regression analysis) showed that organisations in South Africa had invested and adopted more of Digital Talent and Digital Media strategies and less of Digital Org (Design & Culture) and Digital ERM HRM strategies across the HR value chain and as a result, had gained more value at relational level, followed by that at operational level. They gained the least value at transformational level. It was therefore revealed that if HRM professionals, managers and leaders within organisations want to boost the contribution of the HRM function towards achieving the strategic goals of the organisation (transformational level), digitalising the function is one of the best ways. They can achieve this by investing more of HRM Digital Strategies related to Digital Org (Design & Culture), followed by Digital Talent and Digital ERM strategies. Challenges related to the adoption of digital strategies across the HR value chain were only found to negatively influence Digital Org (Design & Culture) and Digital ERM strategies, whereas Digital Talent and Digital Media strategies were not negatively influenced. Based on the literature and empirical results of this study, an integrative HRM digitalisation model was designed to provide a framework approach for implementing HRM digitalisation in South African organisations. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Chapano, Munodani
- Date: 2022-04
- Subjects: Personnel management , Human Resources Assessment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57578 , vital:58094
- Description: The main objective of this study was to determine the extent and nature of value that HRM digitalisation can add to the South African workplace. Digitalisation is a product of 4IR, which refers to the process of leveraging and applying 4IR technologies within organisational operations, including HRM, with the aim of optimising business processes. HRM digitalisation refers to the adoption and application of digital HRM technologies of the 4IR in the conduct of HRM practices, policies, activities and transactions to optimise the HRM function. Due to a shortage of studies that shed light on the value contributed by HRM digitalisation in the workplace, a need arises to determine the extent and nature of this value and the strategies needed to unlock this potential in the context of the 4IR. Moreover, in most South African (SA) organisations, there has been a lack of a fully integrated approach to digital HRM. Thus, this study aims at exploring HRM digitalisation and the value it contributes to South African organisations, with the expectation of developing an articulated and integrative HRM digital strategy for South African organisations. This study was accomplished by means of a literature and an empirical study. The literature study provided theoretical information related to challenges and opportunities introduced by the 4IR in the world of work, with specific reference to the South African workplace and which therefore impact HRM and necessitate the need for digitalisation of HRM. In addition, the following were explored: HRM Digital Strategies that could be adopted and add value in the South African workplace; the extent and nature of that value; the challenges probably encountered in doing so and possible means to overcome the challenges. The discussion led to the development of a hypothetical, theoretical model of HRM digitalisation in the South African workplace. The hypothetical model was used as the basis for the development of a measuring instrument used to collect empirical data for this study. The empirical study used the online questionnaire survey as the data collection instrument that measured the extent and nature of value that various HRM Digital Strategies could vii | P a g e add to the South African workplace; perceived value and hard evidence of the impact of HRM digitalisation; and the extent and nature of challenges associated with the Adoption of HRM Digital Strategies across the HR value chain. The online survey questionnaire was administered to HR directors, HR managers, HR practitioners and line managers who worked in the automotive manufacturing industry in the municipalities of Nelson Mandela Bay in Port Elizabeth and Buffalo City in East London in the Eastern Cape Province of South Africa. A non-probability sampling procedure which comprised a combination of purposive and snowball sampling methods was used to select participants for the study (n = 312). The results from the empirical study, computed using Exploratory Factor Analysis (EFA), descriptive statistics and inferential statistics (such as paired-sample t-tests, Pearson’s product moment correlation and regression analysis) showed that organisations in South Africa had invested and adopted more of Digital Talent and Digital Media strategies and less of Digital Org (Design & Culture) and Digital ERM HRM strategies across the HR value chain and as a result, had gained more value at relational level, followed by that at operational level. They gained the least value at transformational level. It was therefore revealed that if HRM professionals, managers and leaders within organisations want to boost the contribution of the HRM function towards achieving the strategic goals of the organisation (transformational level), digitalising the function is one of the best ways. They can achieve this by investing more of HRM Digital Strategies related to Digital Org (Design & Culture), followed by Digital Talent and Digital ERM strategies. Challenges related to the adoption of digital strategies across the HR value chain were only found to negatively influence Digital Org (Design & Culture) and Digital ERM strategies, whereas Digital Talent and Digital Media strategies were not negatively influenced. Based on the literature and empirical results of this study, an integrative HRM digitalisation model was designed to provide a framework approach for implementing HRM digitalisation in South African organisations. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Impacts of algal blooms in a temperate Estuarine fish nursery area, South Africa
- Authors: Bornman, Eugin
- Date: 2022-04
- Subjects: Cyanobacterial toxins --Environmental aspects , Estuarine eutrophication --South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55899 , vital:54398
- Description: Anthropogenically-derived eutrophication and Harmful Algal Blooms (HABs) are an increasing threat to estuarine ecosystems globally. The rapid population growth in coastal areas and the mismanagement of water resources have led to the rapid increase in eutrophication in estuaries. Consequently, HABs have become frequent phenomena with severe impacts on the ecological functioning of these systems. A paucity exists in understanding the specific mechanisms of how HABs impact estuarine communities globally. This has not been studied in South Africa, despite the observed increase in the occurrence of HABs in the past few decades. Therefore, this study investigated the impact of HABs on the ecological functioning of the anthropogenically altered Sundays Estuary, South Africa, which is affected by predictable and recurrent HABs of the raphidophyte, Heterosigma akashiwo. This study found that a high density (> 1000 cell m L-1 ) of H. akashiwo was present during all but the winter months in the poly- to mesohaline zone, yet it peaked in warmer spring/summer months with a density of ca. 70 000 cell m L-1 corresponding to 800 µg Chl-a L -1 . This species significantly altered the estuary's water quality, causing supersaturated surface- and hypoxic bottom-water during severe HABs or referred to as hypereutrophic bloom phases (> 60 µg Chl-a L -1 ). Despite these changes, the common copepod, Pseudodiaptomus hessei, occurred at similar densities among HAB phases and responded to similar triggers to the HAB. However, a shift in predator-prey interactions within the zooplankton community was evident, with scavenger or opportunist species such as the isopod, Cirolana fluviatilis, and the polychaete, Perinereis falsovariegata, occurring at higher densities during hypereutrophic bloom phases. The overall abundance of juvenile and small adult fishes were high during HABs, but the diversity decreased during HABs. Some species, notably the Mugilidae occurred at lower densities during HABs. Mugilidae also had pronounced histological gill alterations and a lowered proportion of secondary lamellae available for gas exchange during an in situ cage experiment where fishes were isolated inside and outside the HAB. Deformities such as tumorous growths were also found for the first time in a South African Estuary. This indicated a stressed population of Mugilidae in the Sundays Estuary. The ubiquitous mugilid, Mugil cephalus, actively avoided HABs during an acoustic telemetry study, despite having a home range that overlapped the HAB area. Tagged individuals mostly occupied areas directly above the HAB in the upper mesohaline to lower oligohaline zones and only iv briefly transitioned through the HAB area to utilise the lower reaches of the estuary. Since the formation of HABs is reliant on various factors, including specific species responses, environmental variables, nutrient enrichment, and flow characteristics, the impacts of HABs on estuarine communities may vary between estuarine systems or affected species. Therefore, more research that focuses on the impacts of HABs on estuaries is needed to limit the potential loss of ecosystem services. Particularly in light of further unsustainable development, upstream freshwater abstraction and climate change, will cause more frequent and severe HABs, that may result in fish population declines in the long-term. Better management and mitigation strategies are needed to reduce HAB formation such as reducing nutrient enrichment and restoring natural freshwater flow and flooding events to the Sundays Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Bornman, Eugin
- Date: 2022-04
- Subjects: Cyanobacterial toxins --Environmental aspects , Estuarine eutrophication --South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55899 , vital:54398
- Description: Anthropogenically-derived eutrophication and Harmful Algal Blooms (HABs) are an increasing threat to estuarine ecosystems globally. The rapid population growth in coastal areas and the mismanagement of water resources have led to the rapid increase in eutrophication in estuaries. Consequently, HABs have become frequent phenomena with severe impacts on the ecological functioning of these systems. A paucity exists in understanding the specific mechanisms of how HABs impact estuarine communities globally. This has not been studied in South Africa, despite the observed increase in the occurrence of HABs in the past few decades. Therefore, this study investigated the impact of HABs on the ecological functioning of the anthropogenically altered Sundays Estuary, South Africa, which is affected by predictable and recurrent HABs of the raphidophyte, Heterosigma akashiwo. This study found that a high density (> 1000 cell m L-1 ) of H. akashiwo was present during all but the winter months in the poly- to mesohaline zone, yet it peaked in warmer spring/summer months with a density of ca. 70 000 cell m L-1 corresponding to 800 µg Chl-a L -1 . This species significantly altered the estuary's water quality, causing supersaturated surface- and hypoxic bottom-water during severe HABs or referred to as hypereutrophic bloom phases (> 60 µg Chl-a L -1 ). Despite these changes, the common copepod, Pseudodiaptomus hessei, occurred at similar densities among HAB phases and responded to similar triggers to the HAB. However, a shift in predator-prey interactions within the zooplankton community was evident, with scavenger or opportunist species such as the isopod, Cirolana fluviatilis, and the polychaete, Perinereis falsovariegata, occurring at higher densities during hypereutrophic bloom phases. The overall abundance of juvenile and small adult fishes were high during HABs, but the diversity decreased during HABs. Some species, notably the Mugilidae occurred at lower densities during HABs. Mugilidae also had pronounced histological gill alterations and a lowered proportion of secondary lamellae available for gas exchange during an in situ cage experiment where fishes were isolated inside and outside the HAB. Deformities such as tumorous growths were also found for the first time in a South African Estuary. This indicated a stressed population of Mugilidae in the Sundays Estuary. The ubiquitous mugilid, Mugil cephalus, actively avoided HABs during an acoustic telemetry study, despite having a home range that overlapped the HAB area. Tagged individuals mostly occupied areas directly above the HAB in the upper mesohaline to lower oligohaline zones and only iv briefly transitioned through the HAB area to utilise the lower reaches of the estuary. Since the formation of HABs is reliant on various factors, including specific species responses, environmental variables, nutrient enrichment, and flow characteristics, the impacts of HABs on estuarine communities may vary between estuarine systems or affected species. Therefore, more research that focuses on the impacts of HABs on estuaries is needed to limit the potential loss of ecosystem services. Particularly in light of further unsustainable development, upstream freshwater abstraction and climate change, will cause more frequent and severe HABs, that may result in fish population declines in the long-term. Better management and mitigation strategies are needed to reduce HAB formation such as reducing nutrient enrichment and restoring natural freshwater flow and flooding events to the Sundays Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Investigating the first level of pass -through effects of the SACU region monetary transmission mechanism
- Authors: Mkhombo, Thando
- Date: 2022-04
- Subjects: Monetary unions -- Africa, Southern , Foreign exchange market
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55998 , vital:54562
- Description: The purpose of this thesis is to investigate the first-level pass-through effects of monetary policy transmission in SACU using the wavelet analysis methodology. The thesis comprises four empirical themes. 1. Investigating the time-frequency relationship in the Fisher’s effect for SACU countries. 2. Investigating the time-frequency relationship in the Purchasing Power Parity (PPP) for SACU countries. 3. Investigating the time-frequency relationship between the exchange rate and the stock returns for SACU countries. 4. Investigating the time-frequency relationship between interest rates, exchange rates, and stock returns for SACU countries. Whilst there exists a considerable amount of empirical works which have studied the four themes in SACU countries that are covered in this study, there is a need for more empirical investigation for several reasons. Firstly, a majority of the studies have focused on South Africa with very little empirical literature existing for Botswana and Lesotho. Secondly, the previous SACU based studies present contradicting findings. Thirdly, Most of these studies did not cover the themes comprehensively, as is the case in this study. Finally, to the best of my knowledge, this methodology has not been employed in any SACU related literature until now. Altogether, the thesis bridges the inconsistencies found in previous SACU-related literature and offers fresh implications for policymakers and market participants. From an empirical perspective, the wavelet coherence analysis proves to be a powerful tool in reconciling previous contradicting empirical evidence on the existence of the Fisher effect in SACU countries. From a policy perspective, more fined tuned implications are derived from the findings of the study as wavelets are able to depict a more accurate description of the different first-level monetary transmission relationships. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School for Economics, Development and Tourism, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mkhombo, Thando
- Date: 2022-04
- Subjects: Monetary unions -- Africa, Southern , Foreign exchange market
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55998 , vital:54562
- Description: The purpose of this thesis is to investigate the first-level pass-through effects of monetary policy transmission in SACU using the wavelet analysis methodology. The thesis comprises four empirical themes. 1. Investigating the time-frequency relationship in the Fisher’s effect for SACU countries. 2. Investigating the time-frequency relationship in the Purchasing Power Parity (PPP) for SACU countries. 3. Investigating the time-frequency relationship between the exchange rate and the stock returns for SACU countries. 4. Investigating the time-frequency relationship between interest rates, exchange rates, and stock returns for SACU countries. Whilst there exists a considerable amount of empirical works which have studied the four themes in SACU countries that are covered in this study, there is a need for more empirical investigation for several reasons. Firstly, a majority of the studies have focused on South Africa with very little empirical literature existing for Botswana and Lesotho. Secondly, the previous SACU based studies present contradicting findings. Thirdly, Most of these studies did not cover the themes comprehensively, as is the case in this study. Finally, to the best of my knowledge, this methodology has not been employed in any SACU related literature until now. Altogether, the thesis bridges the inconsistencies found in previous SACU-related literature and offers fresh implications for policymakers and market participants. From an empirical perspective, the wavelet coherence analysis proves to be a powerful tool in reconciling previous contradicting empirical evidence on the existence of the Fisher effect in SACU countries. From a policy perspective, more fined tuned implications are derived from the findings of the study as wavelets are able to depict a more accurate description of the different first-level monetary transmission relationships. , Thesis (PhD) -- Faculty of Business and Economic Sciences, School for Economics, Development and Tourism, 2022
- Full Text:
- Date Issued: 2022-04
Pharmacological, toxicological and phytochemical evaluation of helichrysum petiolare hilliard & b.l. burtt - an indigenous plant traditionally used in the treatment of diabetes in the eastern cape province of South Africa
- Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Authors: Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Date: 2022-04
- Subjects: Diabetes -- Alternative treatment , Traditional medicine , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22787 , vital:52755
- Description: Diabetes mellitus is one of the leading causes of death in South Africa, and it has already placed significant stress on the country’s health sector and economy. The orthodox hypoglycaemic drugs are not only ineffective in the management of the disease and its complications, but they also possess unwanted side effects. The need for alternative non-toxic drugs is therefore imperative. Various studies have listed several medicinal plants that can be successfully used in the herbal treatment of diabetes and have investigated them for their anti-diabetic potentials in vivo and/or in vitro. Out of the different potential herbal species, plants belonging to the Asteraceae family possess highly potent hypoglycaemic properties with negligible toxicities. Five Asteraceae plants widely used in different parts of South Africa for the treatment of diabetes were reviewed. The review provided an update of scientific evidence on the hypoglycaemic properties of the plants. However, Helichrysum petiolare was studied extensively in this study for its antidiabetic activity H. petiolare has been listed in many ethnobotanical surveys as a plant with potent hypoglycaemic potential, this, however, has not been properly verified in scientific literature and there has hardly been any study on the essential oil and nutritional composition, and antioxidant, antidiabetic, and cytotoxicity potentials of the plant. The effects of hydro-distillation (HD) and solvent-free microwave extraction (SFME) methods on the chemical constituents of H. petiolare-derived essential oils were evaluated. The SFME method had a higher yield of essential oil than the HD. There were substantial amounts of monoterpenes, monoterpene alcohols, sesquiterpenes, and sesquiterpene alcohols in both essential oils obtained, but these compounds were more profound in the SFME derived essential oil which has 62 compounds compared to the 52 derived through HD. The SFME derived essential oil can therefore be said to be of better quality than the HD method. The compounds obtained in the essential oils have high pharmaceutical and cosmetic value, and as observed in this study, their quantity is dependent on the method of extraction (Ibáñez and Blázquez, 2021; Kaur et al., 2021). The proximate analysis of the whole plant of H. petiolare showed high levels of Acid Detergent Fibre (ADF), vitamins (A, C and E), Neutral Detergent Fibre (NDF), and minerals. The high ADF level is believed to be responsible for the low energy, fat and carbohydrate levels observed in the study. The result showed a high level of oxalate and therefore suggests cooking of the plant before human consumption. Overall nutrition and mineral compositions of the plant showed that H. petiolare is immensely rich in vital nutrients that are of great importance to health and metabolism; these nutrients are suggested to be partly responsible for the plant’s useful medicinal properties. The phytochemical contents of the acetone (ACQ), ethanol (ETQ), and boiled (BAQ) and cold (CAQ) aqueous whole-plant extracts of Helichrysum petiolare were determined using standard phytochemical reaction methods. ABTS, DPPH, NO and TAC assays were used to evaluate their antioxidant properties. The highest total phenolic content (212,963 mg/g) was reported in the BAQ extract, while the ETQ had the highest flavonoid (172.393 mg/g) and proanthocyanidin contents (65.855 mg/g). Alkaloids, flavonols, and saponin were highest in the ACQ extract, while the CAQ had the lowest phytochemical content. Among the extracts, the BAQ had the highest DPPH•+ (IC50 0.02 mg/mL) and ABTS•+ (IC50 0.07) inhibition capacities, while the ETQ exhibited the highest NO• Inhibition (IC50 0.41 mg/mL) and TAC (IC50 0.19 mg/mL). These findings justify the use of H. petiolare in traditional medicine and further recommend the ETQ and BAQ extracts of the plant as more effective extracts for medicinal treatment. The hepatotoxicity (cytotoxicity, mitotoxicity and lipotoxicity) potential of the BAQ, CAQ and ETQ extracts of Helichrysum petiolare was evaluated using standard procedures. The results showed negligible BAQ and CAQ cytotoxicities, which were further, corroborated by stability in the mitochondrial membrane potentials and were congruent with the CAQ and BAQ results for steatosis and phospholipidosis. The data suggested favourable CAQ and BAQ toxicity profiles with limited risks for hepatotoxicity. The ETQ extract, however, showed significantly high levels of cytotoxicity and lipotoxicity, and a low level of mitotoxicity. Our result suggested a potential risk of the ETQ extract for hepatotoxicity but appears partly independent of direct mitochondrial involvement. Glucose uptake assay showed significantly increased glucose uptake in the BAQ and CAQ treated L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α–amylase and α-glucosidase activities as compared to CAQ. The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus. This study provides up to date scientific information on the use of H. petiolare in the treatment of diabetes mellitus in the Eastern Cape of South Africa. It justifies the use of this plant in herbal medicine and sheds more light on its previously vaguely understood nutritional and medicinal potentials. More studies, however, need to be done to isolate, identify and purify the constituent bioactive compound(s). Their dosage of application and mode of action also needs to be understood. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Aladejana, Adebowale Emmanuel https://orcid.org/0000-0003-1871-926X
- Date: 2022-04
- Subjects: Diabetes -- Alternative treatment , Traditional medicine , Medicinal plants
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22787 , vital:52755
- Description: Diabetes mellitus is one of the leading causes of death in South Africa, and it has already placed significant stress on the country’s health sector and economy. The orthodox hypoglycaemic drugs are not only ineffective in the management of the disease and its complications, but they also possess unwanted side effects. The need for alternative non-toxic drugs is therefore imperative. Various studies have listed several medicinal plants that can be successfully used in the herbal treatment of diabetes and have investigated them for their anti-diabetic potentials in vivo and/or in vitro. Out of the different potential herbal species, plants belonging to the Asteraceae family possess highly potent hypoglycaemic properties with negligible toxicities. Five Asteraceae plants widely used in different parts of South Africa for the treatment of diabetes were reviewed. The review provided an update of scientific evidence on the hypoglycaemic properties of the plants. However, Helichrysum petiolare was studied extensively in this study for its antidiabetic activity H. petiolare has been listed in many ethnobotanical surveys as a plant with potent hypoglycaemic potential, this, however, has not been properly verified in scientific literature and there has hardly been any study on the essential oil and nutritional composition, and antioxidant, antidiabetic, and cytotoxicity potentials of the plant. The effects of hydro-distillation (HD) and solvent-free microwave extraction (SFME) methods on the chemical constituents of H. petiolare-derived essential oils were evaluated. The SFME method had a higher yield of essential oil than the HD. There were substantial amounts of monoterpenes, monoterpene alcohols, sesquiterpenes, and sesquiterpene alcohols in both essential oils obtained, but these compounds were more profound in the SFME derived essential oil which has 62 compounds compared to the 52 derived through HD. The SFME derived essential oil can therefore be said to be of better quality than the HD method. The compounds obtained in the essential oils have high pharmaceutical and cosmetic value, and as observed in this study, their quantity is dependent on the method of extraction (Ibáñez and Blázquez, 2021; Kaur et al., 2021). The proximate analysis of the whole plant of H. petiolare showed high levels of Acid Detergent Fibre (ADF), vitamins (A, C and E), Neutral Detergent Fibre (NDF), and minerals. The high ADF level is believed to be responsible for the low energy, fat and carbohydrate levels observed in the study. The result showed a high level of oxalate and therefore suggests cooking of the plant before human consumption. Overall nutrition and mineral compositions of the plant showed that H. petiolare is immensely rich in vital nutrients that are of great importance to health and metabolism; these nutrients are suggested to be partly responsible for the plant’s useful medicinal properties. The phytochemical contents of the acetone (ACQ), ethanol (ETQ), and boiled (BAQ) and cold (CAQ) aqueous whole-plant extracts of Helichrysum petiolare were determined using standard phytochemical reaction methods. ABTS, DPPH, NO and TAC assays were used to evaluate their antioxidant properties. The highest total phenolic content (212,963 mg/g) was reported in the BAQ extract, while the ETQ had the highest flavonoid (172.393 mg/g) and proanthocyanidin contents (65.855 mg/g). Alkaloids, flavonols, and saponin were highest in the ACQ extract, while the CAQ had the lowest phytochemical content. Among the extracts, the BAQ had the highest DPPH•+ (IC50 0.02 mg/mL) and ABTS•+ (IC50 0.07) inhibition capacities, while the ETQ exhibited the highest NO• Inhibition (IC50 0.41 mg/mL) and TAC (IC50 0.19 mg/mL). These findings justify the use of H. petiolare in traditional medicine and further recommend the ETQ and BAQ extracts of the plant as more effective extracts for medicinal treatment. The hepatotoxicity (cytotoxicity, mitotoxicity and lipotoxicity) potential of the BAQ, CAQ and ETQ extracts of Helichrysum petiolare was evaluated using standard procedures. The results showed negligible BAQ and CAQ cytotoxicities, which were further, corroborated by stability in the mitochondrial membrane potentials and were congruent with the CAQ and BAQ results for steatosis and phospholipidosis. The data suggested favourable CAQ and BAQ toxicity profiles with limited risks for hepatotoxicity. The ETQ extract, however, showed significantly high levels of cytotoxicity and lipotoxicity, and a low level of mitotoxicity. Our result suggested a potential risk of the ETQ extract for hepatotoxicity but appears partly independent of direct mitochondrial involvement. Glucose uptake assay showed significantly increased glucose uptake in the BAQ and CAQ treated L6 and C3A cell lines. The CAQ extract enhanced glucose uptake more in the L6 myocytes than in the C3A cell-lines hepatocytes. The BAQ extract showed higher levels of inhibition on α–amylase and α-glucosidase activities as compared to CAQ. The BAQ and CAQ extracts of H. petiolare may, therefore, contain pharmacologically active and relatively non-toxic hypoglycaemic chemicals, which may be effective substitutes in the treatment of diabetes mellitus. This study provides up to date scientific information on the use of H. petiolare in the treatment of diabetes mellitus in the Eastern Cape of South Africa. It justifies the use of this plant in herbal medicine and sheds more light on its previously vaguely understood nutritional and medicinal potentials. More studies, however, need to be done to isolate, identify and purify the constituent bioactive compound(s). Their dosage of application and mode of action also needs to be understood. , Thesis (PhD) -- Faculty of Science and Agriculture, 2022
- Full Text:
- Date Issued: 2022-04
Phytochemical investigation and antidiabetic activity of cissampelos capensis and strychnos henningsii the Eastern Cape medicinal plants
- Authors: Latolla, Nehemiah Solomon
- Date: 2022-04
- Subjects: Medicinal plants -- Eastern Cape (South Africa) , Endemic plants -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56145 , vital:55956
- Description: Diabetes mellitus is recorded as a significant health crisis in South Africa and various medicinal plants are used for the management of diabetes. However, the chemistry and bioactivity associated with these plants' antidiabetic activity are still lacking. Cissampelos capensis L.f. and Strychnos henningsii Gilg are among the plants utilised to manage diabetes in the Eastern Cape Province, South Africa. C. capensis and S. henningsii are known for their isoquinoline – and indole alkaloids, respectively. Other phytochemical groups associated with antidiabetic activity are the phenols, flavonoids, and terpenes. Thus, this study aimed to evaluate in-depth the phytochemical profiling, alkaloidal identification, and structural characterisation of phytochemicals isolated from these plants. Also, subsequent in vitro antidiabetic screening of the crude extracts and isolated compounds from both plants was done. The phytochemical profiling was performed by employing a qualitative and quantitative approach through high-performance thin layer chromatography (HPTLC) and UV-spectrometry. Further analysis for the identification of alkaloids was done by using LCMS. Fractionation and purification of crude extracts were achieved through crystallisation and various chromatographic techniques. NMR, HRMS, UV/Vis, FTIR, and XRD spectroscopic techniques were used to characterise isolated compounds. In vitro antidiabetic activity screening involved the investigation of cytotoxicity, antioxidant activity, alpha-amylase – and/or alpha-glucosidase inhibition (particular to type II diabetes). C. capensis and S. henningsii extracts tested positive for alkaloids, phenolics, flavonoids, and terpenes through HPTLC screening. Quantitative estimation by UV spectrometry of these phytochemical groups detected the highest concentration of alkaloids, followed by flavonoids, phenolics, and terpenes content. The in vitro antidiabetic biological screening of the various crude extracts suggested that the presence of alkaloids, flavonoids, phenolics, and terpenes fostered favourable biological activity. The LCMS of the known alkaloidal constituents from C. capensis detected the presence of ten alkaloids, including glaziovine, lauroscholtzine, pronuciferine and vi salutardine. Seven known alkaloids and one triterpene were detected from S. henningsii, including holtsiine, 23-hdroxyspermostrychnine, henningsiine, and the triterpene, friedelin. These findings suggest that C. capensis and S. henningsii have similar phytochemical constituents compared to the species reported in literature. However, the distribution of the phytochemicals in the various plant parts differed from previous accounts. , Thesis (PhD) -- Faculty of Science,School of Biomecular and Chemical Sciences , 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Latolla, Nehemiah Solomon
- Date: 2022-04
- Subjects: Medicinal plants -- Eastern Cape (South Africa) , Endemic plants -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56145 , vital:55956
- Description: Diabetes mellitus is recorded as a significant health crisis in South Africa and various medicinal plants are used for the management of diabetes. However, the chemistry and bioactivity associated with these plants' antidiabetic activity are still lacking. Cissampelos capensis L.f. and Strychnos henningsii Gilg are among the plants utilised to manage diabetes in the Eastern Cape Province, South Africa. C. capensis and S. henningsii are known for their isoquinoline – and indole alkaloids, respectively. Other phytochemical groups associated with antidiabetic activity are the phenols, flavonoids, and terpenes. Thus, this study aimed to evaluate in-depth the phytochemical profiling, alkaloidal identification, and structural characterisation of phytochemicals isolated from these plants. Also, subsequent in vitro antidiabetic screening of the crude extracts and isolated compounds from both plants was done. The phytochemical profiling was performed by employing a qualitative and quantitative approach through high-performance thin layer chromatography (HPTLC) and UV-spectrometry. Further analysis for the identification of alkaloids was done by using LCMS. Fractionation and purification of crude extracts were achieved through crystallisation and various chromatographic techniques. NMR, HRMS, UV/Vis, FTIR, and XRD spectroscopic techniques were used to characterise isolated compounds. In vitro antidiabetic activity screening involved the investigation of cytotoxicity, antioxidant activity, alpha-amylase – and/or alpha-glucosidase inhibition (particular to type II diabetes). C. capensis and S. henningsii extracts tested positive for alkaloids, phenolics, flavonoids, and terpenes through HPTLC screening. Quantitative estimation by UV spectrometry of these phytochemical groups detected the highest concentration of alkaloids, followed by flavonoids, phenolics, and terpenes content. The in vitro antidiabetic biological screening of the various crude extracts suggested that the presence of alkaloids, flavonoids, phenolics, and terpenes fostered favourable biological activity. The LCMS of the known alkaloidal constituents from C. capensis detected the presence of ten alkaloids, including glaziovine, lauroscholtzine, pronuciferine and vi salutardine. Seven known alkaloids and one triterpene were detected from S. henningsii, including holtsiine, 23-hdroxyspermostrychnine, henningsiine, and the triterpene, friedelin. These findings suggest that C. capensis and S. henningsii have similar phytochemical constituents compared to the species reported in literature. However, the distribution of the phytochemicals in the various plant parts differed from previous accounts. , Thesis (PhD) -- Faculty of Science,School of Biomecular and Chemical Sciences , 2022
- Full Text:
- Date Issued: 2022-04
Rethinking the informal settlements upgrading programmes in the Free State Province, South Africa: a transformative and multi-faceted model
- Authors: Sive Dintsi
- Date: 2022-04
- Subjects: Squatter settlements --South Africa -- Free State , City planning South Africa --Citizen participation
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55987 , vital:54561
- Description: This thesis intended to reveal the factors that contributed to the formulation of the informal settlements upgrading programmes in the Free State, South Africa, from an institutional perspective; subsequently to conceptualise a transformative and multi faceted model for the development and management of human settlements. The mixed methods exploratory research design has been applied in this study. This research design has allowed for the implementation of research methods including the qualitative inductive content analysis method, the case study method, and the semi structured survey questionnaire method. The data collection methods used comprised both primary and secondary data. Primary data involved online surveys and field observations. Secondary data comprised of an inductive analysis of written sources. The main findings of the study were as follows. First, the policy design and implementation processes have been misaligned. Second, there has been inadequate stakeholder engagements. Third, the government has not prioritised the employment of specialists in the field of housing and human settlements. Fourth, corruption has caused the state to fail to provide adequate housing for all. Fifth, municipalities are unable to identify and define existing informal settlements. Lastly, illegal immigration is causing a rapid increase in the number of informal settlements. This thesis proffered key recommendations based on the conclusions drawn from these findings. First, there must be an implementation of an integrated model for the preparation of upgrading policy. Second, communication technology education for officials of the state must be enhanced. Third, the government must prioritise the employment of experts in upgrading work. Fourth, the upgrading policy must reflect the paradigm shift from housing to human settlements. Fifth, municipalities need to be systematically transformed and improved for their functions on upgrading. Finally, illegal immigration must be firmly monitored while legal immigration is discouraged. To this end, this thesis has presented a strong viewpoint that limits the influx of immigrants into unproclaimed urban land that leads to the growth of informal settlements. The study has also strongly advocated for the legal spatial placement of South African citizens and legal immigrants on strategically and socio-economically viable land, where it is suitably available and owned by the state. Housing in the thesis has been viewed as one of the essential instruments that must inevitably emerge as a prospect towards xiv effectively unlocking improved living conditions in informal settlements; rather than housing being perceived as human settlements. , Thesis (PhD) -- Faculty of Engineering, the Built Environment and Information Technology, School of the Built Environment, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Sive Dintsi
- Date: 2022-04
- Subjects: Squatter settlements --South Africa -- Free State , City planning South Africa --Citizen participation
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55987 , vital:54561
- Description: This thesis intended to reveal the factors that contributed to the formulation of the informal settlements upgrading programmes in the Free State, South Africa, from an institutional perspective; subsequently to conceptualise a transformative and multi faceted model for the development and management of human settlements. The mixed methods exploratory research design has been applied in this study. This research design has allowed for the implementation of research methods including the qualitative inductive content analysis method, the case study method, and the semi structured survey questionnaire method. The data collection methods used comprised both primary and secondary data. Primary data involved online surveys and field observations. Secondary data comprised of an inductive analysis of written sources. The main findings of the study were as follows. First, the policy design and implementation processes have been misaligned. Second, there has been inadequate stakeholder engagements. Third, the government has not prioritised the employment of specialists in the field of housing and human settlements. Fourth, corruption has caused the state to fail to provide adequate housing for all. Fifth, municipalities are unable to identify and define existing informal settlements. Lastly, illegal immigration is causing a rapid increase in the number of informal settlements. This thesis proffered key recommendations based on the conclusions drawn from these findings. First, there must be an implementation of an integrated model for the preparation of upgrading policy. Second, communication technology education for officials of the state must be enhanced. Third, the government must prioritise the employment of experts in upgrading work. Fourth, the upgrading policy must reflect the paradigm shift from housing to human settlements. Fifth, municipalities need to be systematically transformed and improved for their functions on upgrading. Finally, illegal immigration must be firmly monitored while legal immigration is discouraged. To this end, this thesis has presented a strong viewpoint that limits the influx of immigrants into unproclaimed urban land that leads to the growth of informal settlements. The study has also strongly advocated for the legal spatial placement of South African citizens and legal immigrants on strategically and socio-economically viable land, where it is suitably available and owned by the state. Housing in the thesis has been viewed as one of the essential instruments that must inevitably emerge as a prospect towards xiv effectively unlocking improved living conditions in informal settlements; rather than housing being perceived as human settlements. , Thesis (PhD) -- Faculty of Engineering, the Built Environment and Information Technology, School of the Built Environment, 2022
- Full Text:
- Date Issued: 2022-04
Scenarios for South Africa’s ocean economy towards 2060
- Authors: Hadi, Nomtha
- Date: 2022-04
- Subjects: Sustainable development--South Africa , Economic development--South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57676 , vital:58195
- Description: The ocean is becoming the new focal point in the discourse on growth and sustainable development, both at national and international levels. Scenario planning improves the quality of the strategic conversations that organisations need to have as a position in preparing for the future. In this research, scenarios for South Africa’s ocean economy towards 2060 were developed and explored by considering the six key ocean sectors as outlined in the Operations Phakisa Strategy, namely, Marine Transport and Manufacturing, Offshore Oil and Gas Exploration, Aquaculture, Small Harbours, Coastal and Marine Tourism, Marine Protection Services and Ocean Governance. The research process was guided by Inayatullah’s six pillars and linked methods towards scenario development. Existing studies do not take into consideration the various social, technological, economic, environmental, political, legislative and ethical factors influencing the growth of the ocean economy. With the ocean increasingly being considered a new economic frontier, sustainable development has become pertinent for supporting and facilitating continued economic growth areas without compromising on environmental, social, or economic factors. Sustainable development within the ocean economy is further supported by Goal 14 of the Sustainable Development Goals, which focuses on conservation and sustainable use of the ocean, sea and marine resources. A literature review was conducted to gain a better understanding of the ocean economy, and primary data was collected through a real-time Delphi platform and semi-structured interviews. The real-time Delphi collected information on the key megatrends that continue to shape the ocean economy and key drivers and wild cards that can affect the sustainability of the key ocean economy industries. In addition, semi-structured interviews collected information on the proposed scenarios and the capacity needed in growing and promoting a sustainable ocean economy for South Africa towards 2060. A scenario matrix was developed for South Africa’s ocean economy and four scenarios and their implications were analysed. The preferred scenario was a resilient ocean economy towards 2060. The study also took a step forward with a view to provide reference to stakeholders and governments in progressing towards a possible scenario and developed an integrated vision for a sustainable ocean economy for South Africa towards 2060. This proposed vision is to ABSTRACT v mitigate against future challenges, collaborate and proactively utilise the development opportunities offered by the ocean economy. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Hadi, Nomtha
- Date: 2022-04
- Subjects: Sustainable development--South Africa , Economic development--South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/57676 , vital:58195
- Description: The ocean is becoming the new focal point in the discourse on growth and sustainable development, both at national and international levels. Scenario planning improves the quality of the strategic conversations that organisations need to have as a position in preparing for the future. In this research, scenarios for South Africa’s ocean economy towards 2060 were developed and explored by considering the six key ocean sectors as outlined in the Operations Phakisa Strategy, namely, Marine Transport and Manufacturing, Offshore Oil and Gas Exploration, Aquaculture, Small Harbours, Coastal and Marine Tourism, Marine Protection Services and Ocean Governance. The research process was guided by Inayatullah’s six pillars and linked methods towards scenario development. Existing studies do not take into consideration the various social, technological, economic, environmental, political, legislative and ethical factors influencing the growth of the ocean economy. With the ocean increasingly being considered a new economic frontier, sustainable development has become pertinent for supporting and facilitating continued economic growth areas without compromising on environmental, social, or economic factors. Sustainable development within the ocean economy is further supported by Goal 14 of the Sustainable Development Goals, which focuses on conservation and sustainable use of the ocean, sea and marine resources. A literature review was conducted to gain a better understanding of the ocean economy, and primary data was collected through a real-time Delphi platform and semi-structured interviews. The real-time Delphi collected information on the key megatrends that continue to shape the ocean economy and key drivers and wild cards that can affect the sustainability of the key ocean economy industries. In addition, semi-structured interviews collected information on the proposed scenarios and the capacity needed in growing and promoting a sustainable ocean economy for South Africa towards 2060. A scenario matrix was developed for South Africa’s ocean economy and four scenarios and their implications were analysed. The preferred scenario was a resilient ocean economy towards 2060. The study also took a step forward with a view to provide reference to stakeholders and governments in progressing towards a possible scenario and developed an integrated vision for a sustainable ocean economy for South Africa towards 2060. This proposed vision is to ABSTRACT v mitigate against future challenges, collaborate and proactively utilise the development opportunities offered by the ocean economy. , Thesis (PhD) -- Faculty of Business and Economic science, 2022
- Full Text:
- Date Issued: 2022-04
Smart catchment management and application in the Swartkops River and Estuary
- Authors: Mmachaka,Thandi Nthabiseng
- Date: 2022-04
- Subjects: Estuarine ecology--South Africa--Swartkops River Estuary
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55932 , vital:54401
- Description: The influence of urbanization and industrialization on natural resources results in complex water resource management. In South Africa, there has been escalating rural-urban migration, a growing population in urban areas, and the mushrooming of informal settlements in cities over the last five decades. In the pursuit of protecting water resources, these contextual realities create a significant challenge to policymakers, planners, and implementers. Due to rapid population growth, climate change, recent droughts, and growing competition among agricultural, industrial, commercial, environmental, and domestic sectors, water resources are presently under severe stress in South Africa. This situation necessitates the effective management of water resources. This study completed a situational assessment for the Swartkops Catchment to examine the extent of pollution, mapped sources of pollution, investigated water quality governance and identified hot spot areas to provide the foundation for effective and efficient catchment management. To determine the current water quality status of the Swartkops Catchment, this current study investigated spatial and temporal variation in physico-chemical parameters, nutrients, and faecal bacteria. This study applied a mixed-method research design using semi-structured interviews and focus groups discussions as data collection methods to investigate the water quality governance of the Swartkops Catchment. Following the situational assessment of the Swartkops Catchment, the effectiveness of applying innovative smart catchment practices to improve water quality was investigated. The word smart in this context refers to innovative mechanisms that will ensure effective and efficient water resources management. The PHP scripting language (Hypertext Preprocessor), Android studio, Wampserver, and JavaScript were used to develop the Water Use Screening System (WUSS) and Pollution Incident Reporting System (PRS). In South Africa, stormwater infrastructure suffers from unsustainable utilization. Stormwater systems discharge into many of the country‘s rivers and estuaries, including Swartkops, leading to water quality degradation. To improve the Recommended Ecological Category (REC) of the Swartkops Estuary to Category C, drivers that contribute to poor water quality must be understood to inform appropriate management interventions. Results from sampling in Markman Canal were compared with historical water quality data. The present study showed that the Markman Canal contributed faecal bacteria, nutrients, and trace metals to the Swartkops Estuary. The Markman Canal was the greatest source of trace metals to the Swartkops Estuary compared to the other point sources entering the estuary. The results show that arsenic and mercury levels in the Markman Canal and the Swartkops Estuary were higher than that previously measured. Iron and copper concentrations were higher in the Markman Canal whereas only copper increased in the Swartkops Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Mmachaka,Thandi Nthabiseng
- Date: 2022-04
- Subjects: Estuarine ecology--South Africa--Swartkops River Estuary
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55932 , vital:54401
- Description: The influence of urbanization and industrialization on natural resources results in complex water resource management. In South Africa, there has been escalating rural-urban migration, a growing population in urban areas, and the mushrooming of informal settlements in cities over the last five decades. In the pursuit of protecting water resources, these contextual realities create a significant challenge to policymakers, planners, and implementers. Due to rapid population growth, climate change, recent droughts, and growing competition among agricultural, industrial, commercial, environmental, and domestic sectors, water resources are presently under severe stress in South Africa. This situation necessitates the effective management of water resources. This study completed a situational assessment for the Swartkops Catchment to examine the extent of pollution, mapped sources of pollution, investigated water quality governance and identified hot spot areas to provide the foundation for effective and efficient catchment management. To determine the current water quality status of the Swartkops Catchment, this current study investigated spatial and temporal variation in physico-chemical parameters, nutrients, and faecal bacteria. This study applied a mixed-method research design using semi-structured interviews and focus groups discussions as data collection methods to investigate the water quality governance of the Swartkops Catchment. Following the situational assessment of the Swartkops Catchment, the effectiveness of applying innovative smart catchment practices to improve water quality was investigated. The word smart in this context refers to innovative mechanisms that will ensure effective and efficient water resources management. The PHP scripting language (Hypertext Preprocessor), Android studio, Wampserver, and JavaScript were used to develop the Water Use Screening System (WUSS) and Pollution Incident Reporting System (PRS). In South Africa, stormwater infrastructure suffers from unsustainable utilization. Stormwater systems discharge into many of the country‘s rivers and estuaries, including Swartkops, leading to water quality degradation. To improve the Recommended Ecological Category (REC) of the Swartkops Estuary to Category C, drivers that contribute to poor water quality must be understood to inform appropriate management interventions. Results from sampling in Markman Canal were compared with historical water quality data. The present study showed that the Markman Canal contributed faecal bacteria, nutrients, and trace metals to the Swartkops Estuary. The Markman Canal was the greatest source of trace metals to the Swartkops Estuary compared to the other point sources entering the estuary. The results show that arsenic and mercury levels in the Markman Canal and the Swartkops Estuary were higher than that previously measured. Iron and copper concentrations were higher in the Markman Canal whereas only copper increased in the Swartkops Estuary. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Synthesis and applications of novel fluorescent and colorimetric coumarin-based sensors towards analyte sensing in aqueous systems
- Authors: Battison, Aidan Leigh
- Date: 2022-04
- Subjects: Water-supply engineering--Technological innovations , Polymers--Optical properties , Fluorescent polymers
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55954 , vital:54558
- Description: The continuous growth of mankind has not been considerate to the environment. The release of millions of tonnes of toxic heavy metal cations and anionic species through industrial, mining, agricultural, and electronic dumping has led to disease and, in many instances, death. This is usually suffered by low-income informal populations residing in third world countries. Moreover, many unnecessary deaths of children are becoming more prevalent because of consumption and contact with contaminated water, agricultural, and animal sources. Bioaccumulation of these toxic species in fish, plants, and animals, inevitably make their way back to the unaware general population. As growth by mining, agriculture, and electronics are indeed vital aspects of human development, the negative side effects of these activities usually continue unregulated. Therefore, as these processes are set to continue until more stringent regulatory processes are put into legislature; low-cost, sensitive, selective organic based sensors are a step in the right direction towards highlighting the need for environmental restoration and remediation; whilst also aiming to preventing unnecessary disease and death in the process. Herein, coumarin derived small-molecule fluorescent and colorimetric sensors for the quantitative and qualitative assessment of cationic and anionic species in aqueous and organic media are described. Ten fluorescent sensors supporting 1,4-disubstituted triazolyl moieties were synthesized according to Cu(I)-catalyzed azide-alkyne cycloaddition “click” reactions. These sensors were screened for their cationic and anionic affinities in a variety of solvent systems. Majority of the sensors responded well towards Fe3+, characterized by a strong fluorescent quenching response with a good degree of sensitivity and selectivity. Selected sensors were further investigated for their affinities towards anionic species; however, they did not display the same degree of selectivity or sensitivity towards these chosen anions. Titration studies of selected sensors with Fe3+ were able to be used towards determining the modes of fluorescent quenching; the photophysical mechanisms by which quenching occurs; stoichiometric binding ratios, association constants, and the number of coordination sites present between the sensors and Fe3+. Reversibility studies of the sensor-metal complex was investigated with EDTA. Partial reversibility was achieved for the chosen sensors with Fe3+. Hydrogen potential studies further described the application of these sensors over a good pH range. The binding site between the sensors and Fe3+ was investigated by NMR studies. , Thesis (PhD) -- Faculty of Science, School of Biomecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Battison, Aidan Leigh
- Date: 2022-04
- Subjects: Water-supply engineering--Technological innovations , Polymers--Optical properties , Fluorescent polymers
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55954 , vital:54558
- Description: The continuous growth of mankind has not been considerate to the environment. The release of millions of tonnes of toxic heavy metal cations and anionic species through industrial, mining, agricultural, and electronic dumping has led to disease and, in many instances, death. This is usually suffered by low-income informal populations residing in third world countries. Moreover, many unnecessary deaths of children are becoming more prevalent because of consumption and contact with contaminated water, agricultural, and animal sources. Bioaccumulation of these toxic species in fish, plants, and animals, inevitably make their way back to the unaware general population. As growth by mining, agriculture, and electronics are indeed vital aspects of human development, the negative side effects of these activities usually continue unregulated. Therefore, as these processes are set to continue until more stringent regulatory processes are put into legislature; low-cost, sensitive, selective organic based sensors are a step in the right direction towards highlighting the need for environmental restoration and remediation; whilst also aiming to preventing unnecessary disease and death in the process. Herein, coumarin derived small-molecule fluorescent and colorimetric sensors for the quantitative and qualitative assessment of cationic and anionic species in aqueous and organic media are described. Ten fluorescent sensors supporting 1,4-disubstituted triazolyl moieties were synthesized according to Cu(I)-catalyzed azide-alkyne cycloaddition “click” reactions. These sensors were screened for their cationic and anionic affinities in a variety of solvent systems. Majority of the sensors responded well towards Fe3+, characterized by a strong fluorescent quenching response with a good degree of sensitivity and selectivity. Selected sensors were further investigated for their affinities towards anionic species; however, they did not display the same degree of selectivity or sensitivity towards these chosen anions. Titration studies of selected sensors with Fe3+ were able to be used towards determining the modes of fluorescent quenching; the photophysical mechanisms by which quenching occurs; stoichiometric binding ratios, association constants, and the number of coordination sites present between the sensors and Fe3+. Reversibility studies of the sensor-metal complex was investigated with EDTA. Partial reversibility was achieved for the chosen sensors with Fe3+. Hydrogen potential studies further described the application of these sensors over a good pH range. The binding site between the sensors and Fe3+ was investigated by NMR studies. , Thesis (PhD) -- Faculty of Science, School of Biomecular and Chemical Sciences, 2022
- Full Text:
- Date Issued: 2022-04
The foraging ecology of female Cape fur seals (Arctocephalus pusillus pusillus) in South Africa
- Botha, Jonathan Aubrey, Kirkman, Stephen, Lombard, Amanda
- Authors: Botha, Jonathan Aubrey , Kirkman, Stephen , Lombard, Amanda
- Date: 2022-04
- Subjects: Seals (Animals)--Habitat—Conservation , Marine ecology—South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55965 , vital:54559
- Description: The marine environment is spatially and temporally dynamic and many marine ecosystems are experiencing impacts of broad-scale climate change. Within these ecosystems, marine predators play a crucial role in ecosystem function through their top-down influences on prey populations. These predators may also respond to bottom-up influences and changes at lower trophic levels. A thorough understanding of marine predator foraging ecology is thus important to improve our understanding of ecosystem function, inform conservation and management measures, and to predict the response of predators to future environmental change. The Cape fur seal (Arctocephalus pusillus pusillus) comprises a major proportion of the southern African marine predator biomass. However, little is known about the foraging distribution and behaviour of the species, despite its obvious importance within the ecosystem and increasing concerns regarding seal-fisheries conflict. Using a variety of technologies, including, GPS and satellite-linked tags, dive behaviour recorders, accelerometers and stable isotope analysis, this thesis investigated the foraging ecology of female Cape fur seals breeding on the coast of South Africa. First, to identify important foraging areas and assess the influence of geographic, temporal and environmental factors on these areas, lactating females from three breeding colonies were fitted with GPS or Argos-linked tracking devices, while individuals from two of these colonies were also fitted with dive behaviour recorders. Results revealed geographic differences in the foraging distributions and ranges of individuals between breeding colonies, which likely reflects a combined influence of ecological setting and density dependant competition. In addition, dive behaviour recorders revealed the occurrence of benthic foraging at both sites where they were deployed, and the dominance of this strategy in some individuals. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Botha, Jonathan Aubrey , Kirkman, Stephen , Lombard, Amanda
- Date: 2022-04
- Subjects: Seals (Animals)--Habitat—Conservation , Marine ecology—South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55965 , vital:54559
- Description: The marine environment is spatially and temporally dynamic and many marine ecosystems are experiencing impacts of broad-scale climate change. Within these ecosystems, marine predators play a crucial role in ecosystem function through their top-down influences on prey populations. These predators may also respond to bottom-up influences and changes at lower trophic levels. A thorough understanding of marine predator foraging ecology is thus important to improve our understanding of ecosystem function, inform conservation and management measures, and to predict the response of predators to future environmental change. The Cape fur seal (Arctocephalus pusillus pusillus) comprises a major proportion of the southern African marine predator biomass. However, little is known about the foraging distribution and behaviour of the species, despite its obvious importance within the ecosystem and increasing concerns regarding seal-fisheries conflict. Using a variety of technologies, including, GPS and satellite-linked tags, dive behaviour recorders, accelerometers and stable isotope analysis, this thesis investigated the foraging ecology of female Cape fur seals breeding on the coast of South Africa. First, to identify important foraging areas and assess the influence of geographic, temporal and environmental factors on these areas, lactating females from three breeding colonies were fitted with GPS or Argos-linked tracking devices, while individuals from two of these colonies were also fitted with dive behaviour recorders. Results revealed geographic differences in the foraging distributions and ranges of individuals between breeding colonies, which likely reflects a combined influence of ecological setting and density dependant competition. In addition, dive behaviour recorders revealed the occurrence of benthic foraging at both sites where they were deployed, and the dominance of this strategy in some individuals. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
The regulation of renewable energy in South Africa
- Van Huyssteen, Cornelis Roelof, Adelman, Sam
- Authors: Van Huyssteen, Cornelis Roelof , Adelman, Sam
- Date: 2022-04
- Subjects: International law and human rights , Climatic changes -- Social aspects --South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56382 , vital:56617
- Description: As a developing country, South Africa’s demand for electricity is accelerating in order to facilitate economic growth and provide the necessary basic services to its people. Historically, the South African government has primarily opted to cater for the country’s electricity needs by means of coal as an affordable fossil fuel-based energy source. However, amidst the world’s changing climate and the plummeting costs of renewable energy technologies, there is increasing global pressure to phase out the use of fossil fuels as the key contributor to anthropogenic climate change and to move towards renewables as the world’s main source of energy. The primary problem highlighted in this thesis is the fact that South Africa’s energy laws have been developed to accommodate fossil fuels as the main source of energy, effectively neglecting the need to incorporate provisions that support and regulate the renewable energy sector. The thesis argues for the need for South Africa to transition away from fossil-fuel and nuclear based energy solutions based on the potential of renewables not only to improve energy security, but also to contribute towards social, economic, and environmental development. However, the transition to renewables and the realisation of its associated benefits will only be realised by means of a regulatory framework dedicated to the development of the renewable energy sector. The researcher argues that, in their current form, South African laws and policies limits the growth of the renewable energy sector. In order to propose reform and to develop the law to support renewable energy sufficiently, the thesis explores international law as well as global best practice in the United Kingdom and Germany related to renewable energy regulation. The comparative analysis allows the researcher to make recommendations to inform the development of South Africa’s renewable energy legal framework. It is argued that, given South Africa’s status as a developing country, such reform must be based upon the fundamental principles of climate change mitigation and social development. Ultimately, it is submitted that, a law dedicated to renewable energy can, and must, play an imperative role in realising the concept of sustainable development in South Africa. , Thesis (LLD) -- Faculty of Law , School of Public Law, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Van Huyssteen, Cornelis Roelof , Adelman, Sam
- Date: 2022-04
- Subjects: International law and human rights , Climatic changes -- Social aspects --South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/56382 , vital:56617
- Description: As a developing country, South Africa’s demand for electricity is accelerating in order to facilitate economic growth and provide the necessary basic services to its people. Historically, the South African government has primarily opted to cater for the country’s electricity needs by means of coal as an affordable fossil fuel-based energy source. However, amidst the world’s changing climate and the plummeting costs of renewable energy technologies, there is increasing global pressure to phase out the use of fossil fuels as the key contributor to anthropogenic climate change and to move towards renewables as the world’s main source of energy. The primary problem highlighted in this thesis is the fact that South Africa’s energy laws have been developed to accommodate fossil fuels as the main source of energy, effectively neglecting the need to incorporate provisions that support and regulate the renewable energy sector. The thesis argues for the need for South Africa to transition away from fossil-fuel and nuclear based energy solutions based on the potential of renewables not only to improve energy security, but also to contribute towards social, economic, and environmental development. However, the transition to renewables and the realisation of its associated benefits will only be realised by means of a regulatory framework dedicated to the development of the renewable energy sector. The researcher argues that, in their current form, South African laws and policies limits the growth of the renewable energy sector. In order to propose reform and to develop the law to support renewable energy sufficiently, the thesis explores international law as well as global best practice in the United Kingdom and Germany related to renewable energy regulation. The comparative analysis allows the researcher to make recommendations to inform the development of South Africa’s renewable energy legal framework. It is argued that, given South Africa’s status as a developing country, such reform must be based upon the fundamental principles of climate change mitigation and social development. Ultimately, it is submitted that, a law dedicated to renewable energy can, and must, play an imperative role in realising the concept of sustainable development in South Africa. , Thesis (LLD) -- Faculty of Law , School of Public Law, 2022
- Full Text:
- Date Issued: 2022-04
The use of psychometric test systems as a pre-selection tool for identifying successful harvesting machine operators
- Authors: Schwegman, Kylle
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55246 , vital:51102
- Description: A shift towards fully mechanized forest activities, such as harvesting and, more recently, silviculture, has occurred from the early 2 000’s. The reason for mechanizing these activities differs for each country, although for most countries there is concern relating to the health and safety of forest workers. With mechanization in harvesting, the forest worker has moved away from the physical intensity of having to fell, debranch, debark and cross-cut trees into logs using either an axe or chainsaw, to operating a machine. Studies revolving around the human element (operator) have been conducted specifically relating to the ergonomics of the machines and how operators may influence machine productivity. Results showed that due to the repetitive nature of the work, the operators are exposed to associated stresses for longer periods. Typical injuries associated to these kinds of stressors are whole body vibrations (WBVs), repetitive hand and arm movements, non-neutral body postures and manual lifting, which lead to musculoskeletal symptoms in the lower back, neck and shoulders. However, as machine technology improves so does the ergonomic conditions which are experienced by machine operators. Machine productivity can be influenced by various factors, with the most influential being tree volume. However, a recent study showed that over 40% of variation in machine productivity has been observed amongst different machine operators operating similar machines. The specific reason for these differences has yet to be determined. However, decision making, motivation, planning capacity, concentration, memory, motor coordination, pattern recognition, logic reasoning, and spatial perception are abilities that have been described as important for successful harvesting work. The pre-selection of operators using psychometric and cognitive tests is not new to forestry, although very little information is available relating to the aptitude test known as the Vienna test system as well as the best possible demographic associated with successful harvesting operators. The overall aim of this study was to determine whether the high variation found amongst harvesting machine operators could be reduced initially through a preselection process which involves the use of aptitude tests (Vienna Test System) and demographic questionnaires. A study was implemented in Zululand, South Africa, testing whether there were significant productivity differences between nine machine operators. , Thesis (PhD) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Schwegman, Kylle
- Date: 2022-04
- Subjects: Port Elizabeth (South Africa) , Eastern Cape (South Africa) , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55246 , vital:51102
- Description: A shift towards fully mechanized forest activities, such as harvesting and, more recently, silviculture, has occurred from the early 2 000’s. The reason for mechanizing these activities differs for each country, although for most countries there is concern relating to the health and safety of forest workers. With mechanization in harvesting, the forest worker has moved away from the physical intensity of having to fell, debranch, debark and cross-cut trees into logs using either an axe or chainsaw, to operating a machine. Studies revolving around the human element (operator) have been conducted specifically relating to the ergonomics of the machines and how operators may influence machine productivity. Results showed that due to the repetitive nature of the work, the operators are exposed to associated stresses for longer periods. Typical injuries associated to these kinds of stressors are whole body vibrations (WBVs), repetitive hand and arm movements, non-neutral body postures and manual lifting, which lead to musculoskeletal symptoms in the lower back, neck and shoulders. However, as machine technology improves so does the ergonomic conditions which are experienced by machine operators. Machine productivity can be influenced by various factors, with the most influential being tree volume. However, a recent study showed that over 40% of variation in machine productivity has been observed amongst different machine operators operating similar machines. The specific reason for these differences has yet to be determined. However, decision making, motivation, planning capacity, concentration, memory, motor coordination, pattern recognition, logic reasoning, and spatial perception are abilities that have been described as important for successful harvesting work. The pre-selection of operators using psychometric and cognitive tests is not new to forestry, although very little information is available relating to the aptitude test known as the Vienna test system as well as the best possible demographic associated with successful harvesting operators. The overall aim of this study was to determine whether the high variation found amongst harvesting machine operators could be reduced initially through a preselection process which involves the use of aptitude tests (Vienna Test System) and demographic questionnaires. A study was implemented in Zululand, South Africa, testing whether there were significant productivity differences between nine machine operators. , Thesis (PhD) -- Faculty of Science, School of Natural Resource Management, 2022
- Full Text:
- Date Issued: 2022-04
Zooplankton dynamics of Algoa Bay (South Africa) under varying oceanographic conditions
- Authors: Bizani,Mfundo
- Date: 2022-04
- Subjects: Marine zooplankton -- South Africa , Climate changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55943 , vital:54554
- Description: the ecological significance of ocean plankton in terms of nutrient cycling and energy transfer is widely recognised, as is their mechanistic link with both oceanographic processes and climate. Consequently, plankton are widely regarded as sentinels of climate change, principally owing to their responsiveness to changing environmental conditions. Developing an understanding of the ecological as well as socio-economic consequences associated with changes in marine plankton dynamics has emerged as a key issue worldwide. Though many exciting advances in this respect have been attained with the aid of long-term plankton time series (>50 y), global environmental datasets and innovative meta-analyses, building deep knowledge of regional bio-physical dynamics and responses to specific perturbed states remains an essential component of the collective effort. Algoa Bay, situated on the warmtemperate south-east coast of South Africa presents a unique opportunity to study key elements of plankton ecology relevant to climate change problems in the regional sense. The embayment is locally subjected to frequent wind-driven upwelling and regionally, to periodic mesoscale oceanographic forcing (e.g., large solitary meanders, Agulhas Current intrusions), all of which culminate in a complex physical and biogeochemical environment. Using zooplankton as the focal component and drawing from a multi-year monthly dataset incorporating a bay-scale sampling framework, the present study addressed three key hypotheses pertaining to 1) drivers of spatio-temporal variability, 2) biomass rate of change over temporal scales using time-series analyses, and 3) community responses to a bay-scale biological perturbation event. Zooplankton biomass exhibited prominent seasonal patterns with bimodal peaks corresponding with near-consistent year-to-year autumn and spring blooms. Overall, the spatial trend showed no heterogeneity, though statistical significance between-station variability was noted per season. An analytical framework involving generalised additive models revealed zooplankton spatial heterogeneity in Algoa Bay to be a function of seasonal variation in a suite of physicochemical variables, including the combined effects of temperature, salinity, dissolved oxygen, total nitrogen and silicate, but not ammonium, phosphate or chlorophyll-a (as proxy for phytoplankton). Fronts (including river plumes), warm water intrusion from the Agulhas Current, and wind-driven upwelling were postulated to be key driving forces. Structural breaks analysis performed on station-specific time series revealed significant incremental increases in zooplankton biomass over time, which in turn, corresponded with a gradual decrease in thermocline depth. The most pronounced increasing effect was associated with a period (2013– 14) of amplified land-derived nutrient input and increasing harmful algal bloom (HAB) activity. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
- Authors: Bizani,Mfundo
- Date: 2022-04
- Subjects: Marine zooplankton -- South Africa , Climate changes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/55943 , vital:54554
- Description: the ecological significance of ocean plankton in terms of nutrient cycling and energy transfer is widely recognised, as is their mechanistic link with both oceanographic processes and climate. Consequently, plankton are widely regarded as sentinels of climate change, principally owing to their responsiveness to changing environmental conditions. Developing an understanding of the ecological as well as socio-economic consequences associated with changes in marine plankton dynamics has emerged as a key issue worldwide. Though many exciting advances in this respect have been attained with the aid of long-term plankton time series (>50 y), global environmental datasets and innovative meta-analyses, building deep knowledge of regional bio-physical dynamics and responses to specific perturbed states remains an essential component of the collective effort. Algoa Bay, situated on the warmtemperate south-east coast of South Africa presents a unique opportunity to study key elements of plankton ecology relevant to climate change problems in the regional sense. The embayment is locally subjected to frequent wind-driven upwelling and regionally, to periodic mesoscale oceanographic forcing (e.g., large solitary meanders, Agulhas Current intrusions), all of which culminate in a complex physical and biogeochemical environment. Using zooplankton as the focal component and drawing from a multi-year monthly dataset incorporating a bay-scale sampling framework, the present study addressed three key hypotheses pertaining to 1) drivers of spatio-temporal variability, 2) biomass rate of change over temporal scales using time-series analyses, and 3) community responses to a bay-scale biological perturbation event. Zooplankton biomass exhibited prominent seasonal patterns with bimodal peaks corresponding with near-consistent year-to-year autumn and spring blooms. Overall, the spatial trend showed no heterogeneity, though statistical significance between-station variability was noted per season. An analytical framework involving generalised additive models revealed zooplankton spatial heterogeneity in Algoa Bay to be a function of seasonal variation in a suite of physicochemical variables, including the combined effects of temperature, salinity, dissolved oxygen, total nitrogen and silicate, but not ammonium, phosphate or chlorophyll-a (as proxy for phytoplankton). Fronts (including river plumes), warm water intrusion from the Agulhas Current, and wind-driven upwelling were postulated to be key driving forces. Structural breaks analysis performed on station-specific time series revealed significant incremental increases in zooplankton biomass over time, which in turn, corresponded with a gradual decrease in thermocline depth. The most pronounced increasing effect was associated with a period (2013– 14) of amplified land-derived nutrient input and increasing harmful algal bloom (HAB) activity. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2022
- Full Text:
- Date Issued: 2022-04
Accountability of the police to provincial governments in South Africa: a comparative analysis of law and practice in the eastern and Western Cape Provinces
- Authors: Tyabazayo, Phumlani
- Date: 2022-03
- Subjects: Police -- South Africa , Police power , Police administration
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22456 , vital:52323
- Description: The 2012 Constitutional Court matter between the national minister of police and the premier of the Western Cape (Minister of Police v Premier of the Western Cape 2013 (12) BCLR 1365 (CC)) concerning the exercise of provincial policing powers as provided for in chapter 11 of the Constitution of South Africa laid bare the tension between the national and provincial governments in the exercise of these powers. Despite the Court’s determination of the dispute, there are still grey areas regarding the constitutional obligations of the provinces with regard to policing. The result has been a lack of clarity and uniformity in the exercise of policing powers by various provinces in South Africa. Based on documentary analysis and interviews, this study explores the parameters of the powers of provinces in policing matters as well as the extent of accountability of the police to provincial governments in South Africa by comparing the law and practice in the Eastern Cape and Western Cape provinces. The study argues that if provinces are to effectively exercise their constitutional powers in policing matters, there needs to be a degree of uniformity in and a mutual understanding of the extent and parameters of provincial policing powers. Only when they clearly understand their powers in policing matters will provincial governments be able to develop legal and policy frameworks to consolidate their powers and effectively hold the police accountable. The study considers whether the current policing powers afforded to provinces are adequate and if not, whether constitutional reform is needed to afford provinces more and clearer policing powers. Furthermore, within the context of participatory democracy, the study takes an in-depth look into the accountability role of Community Police Forums. The study finds that, generally, provincial governments fall short in fulfilling the obligations imposed on them by the Constitution. The study further finds that, in practice, there is still uncertainty about the role of the provincial governments and the Civilian Secretariat for Police in policing matters. Among the recommendations of this study is that section 206 (1) of the Constitution be amended to give provinces power to formulate policing policy in respect of issues peculiar to a particular province. The study also proposes a model to enhance the exercise of provincial policing powers by provincial governments in South Africa. , Thesis (PhD) -- Faculty of Law, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Tyabazayo, Phumlani
- Date: 2022-03
- Subjects: Police -- South Africa , Police power , Police administration
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/22456 , vital:52323
- Description: The 2012 Constitutional Court matter between the national minister of police and the premier of the Western Cape (Minister of Police v Premier of the Western Cape 2013 (12) BCLR 1365 (CC)) concerning the exercise of provincial policing powers as provided for in chapter 11 of the Constitution of South Africa laid bare the tension between the national and provincial governments in the exercise of these powers. Despite the Court’s determination of the dispute, there are still grey areas regarding the constitutional obligations of the provinces with regard to policing. The result has been a lack of clarity and uniformity in the exercise of policing powers by various provinces in South Africa. Based on documentary analysis and interviews, this study explores the parameters of the powers of provinces in policing matters as well as the extent of accountability of the police to provincial governments in South Africa by comparing the law and practice in the Eastern Cape and Western Cape provinces. The study argues that if provinces are to effectively exercise their constitutional powers in policing matters, there needs to be a degree of uniformity in and a mutual understanding of the extent and parameters of provincial policing powers. Only when they clearly understand their powers in policing matters will provincial governments be able to develop legal and policy frameworks to consolidate their powers and effectively hold the police accountable. The study considers whether the current policing powers afforded to provinces are adequate and if not, whether constitutional reform is needed to afford provinces more and clearer policing powers. Furthermore, within the context of participatory democracy, the study takes an in-depth look into the accountability role of Community Police Forums. The study finds that, generally, provincial governments fall short in fulfilling the obligations imposed on them by the Constitution. The study further finds that, in practice, there is still uncertainty about the role of the provincial governments and the Civilian Secretariat for Police in policing matters. Among the recommendations of this study is that section 206 (1) of the Constitution be amended to give provinces power to formulate policing policy in respect of issues peculiar to a particular province. The study also proposes a model to enhance the exercise of provincial policing powers by provincial governments in South Africa. , Thesis (PhD) -- Faculty of Law, 2022
- Full Text:
- Date Issued: 2022-03
An analysis of the internship programme in the Sarah Baartman Health District of the Eastern Cape: a model for effective implementation
- Authors: Feni, Monde Ludick
- Date: 2022-03
- Subjects: Internship programs , Public service employment , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23359 , vital:57617
- Description: The study’s main purpose was to evaluate the processes for Internship Programme Implementation in the Sarah Baartman Health District of the Eastern Cape Department of Health, to determine a Model that can be postulated for improving the Internship Programme Implementation in the Sarah Baartman Health District, wide Public Service and Private Sector. An empirical Study reveals the process for the Internship Programme Implementation has been marred with a significant number of challenges. As part of the recommendations, it was highly stressed that the Sarah Baartman Health District must adopt and embrace the Internship Programme Implementation Model in Figure 6.1 to effectively implement the Internship Programme as a means to deal with the challenges. Data was collected by the investigator from four main groups within the Sarah Baartman Health District. These were Senior Managers, Corporate Services Managers, Mentors, current and past interns. All these groups were directly involved in the internships in the Sarah Baartman Health District Health Department. The investigator got accurate and verified reflections, experiences and understandings of four constructs surrounding the internship programme and they include recruitment and employment of Interns using Best Practices, Training and Development Programmes for Interns Training, Performance Management and Development System for Interns and Mentoring as a Tool to Transfer Knowledge, Skills, Competencies and Attitudes required to Perform Optimally. During interviews, the researcher requested permission from the participants to record their responses digitally. This was done to make sure that no data was lost during the writing of responses from the participants. The questionnaires that were distributed to the interns and mentors had closed-ended questions, but the validity of the questionnaire was ensured by having a space for comments under each question to allow participants to support their answers. An analysis of the questionnaire was done by employing Microsoft Excel and statistics that are descriptive and inferential. The study findings revealed that the recruitment and employment of interns using best practices had a mean score above the required mean of 3, meaning that it is applied acceptably. As much as the construct is acceptable and meets the standard, the item in the construct that pertained to security checks for interns was not done and this is a worrying factor, meaning that the recruitment and employment of interns might be at risk of bringing in interns into the programme who are risky for the organisation. , Thesis (PhD) -- Faculty of Management and Commerce, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Feni, Monde Ludick
- Date: 2022-03
- Subjects: Internship programs , Public service employment , South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/23359 , vital:57617
- Description: The study’s main purpose was to evaluate the processes for Internship Programme Implementation in the Sarah Baartman Health District of the Eastern Cape Department of Health, to determine a Model that can be postulated for improving the Internship Programme Implementation in the Sarah Baartman Health District, wide Public Service and Private Sector. An empirical Study reveals the process for the Internship Programme Implementation has been marred with a significant number of challenges. As part of the recommendations, it was highly stressed that the Sarah Baartman Health District must adopt and embrace the Internship Programme Implementation Model in Figure 6.1 to effectively implement the Internship Programme as a means to deal with the challenges. Data was collected by the investigator from four main groups within the Sarah Baartman Health District. These were Senior Managers, Corporate Services Managers, Mentors, current and past interns. All these groups were directly involved in the internships in the Sarah Baartman Health District Health Department. The investigator got accurate and verified reflections, experiences and understandings of four constructs surrounding the internship programme and they include recruitment and employment of Interns using Best Practices, Training and Development Programmes for Interns Training, Performance Management and Development System for Interns and Mentoring as a Tool to Transfer Knowledge, Skills, Competencies and Attitudes required to Perform Optimally. During interviews, the researcher requested permission from the participants to record their responses digitally. This was done to make sure that no data was lost during the writing of responses from the participants. The questionnaires that were distributed to the interns and mentors had closed-ended questions, but the validity of the questionnaire was ensured by having a space for comments under each question to allow participants to support their answers. An analysis of the questionnaire was done by employing Microsoft Excel and statistics that are descriptive and inferential. The study findings revealed that the recruitment and employment of interns using best practices had a mean score above the required mean of 3, meaning that it is applied acceptably. As much as the construct is acceptable and meets the standard, the item in the construct that pertained to security checks for interns was not done and this is a worrying factor, meaning that the recruitment and employment of interns might be at risk of bringing in interns into the programme who are risky for the organisation. , Thesis (PhD) -- Faculty of Management and Commerce, 2022
- Full Text:
- Date Issued: 2022-03
Code of conduct for learners: A strategy for enhancing positive discipline in selected township schools in Durban, KwaZulu-Natal
- Zondo, Sindiswa Silindokuhle
- Authors: Zondo, Sindiswa Silindokuhle
- Date: 2022-03
- Subjects: School discipline
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21711 , vital:51744
- Description: Dealing with misbehaving learners remains a significant challenge for teachers in South African schools. As the use of corporal punishment and other punitive measures to deal with misbehaving learners is now illegal, alternative positive disciplinary measures have been put in place. The prohibition of negative disciplinary measures has left teachers feeling powerless and frustrated, not knowing how to manage learner behaviour, despite the fact that they are the viable agents tasked with ensuring that positive disciplinary measures are implemented in schools. This study sought to examine how best a code of conduct for learners can be used to enhance positive discipline in schools. To that end, the study offers insights into how positive disciplinary measures may be used, in dealing with learner indiscipline. This is a qualitative study, underpinned by the interpretivist paradigm. The study employed a phenomenological design as a strategy for data collection, to examine how a code of conduct for learners can be used to enhance positive discipline in selected township schools. As this is a qualitative study concerned more with the depth than the breadth of information, the researcher deemed it necessary to focus on two schools, to obtain deep insight into the participants’ lived experiences. Two schools, in Pinetown in Durban, participated in the study. Interviews, observations and document reviews were used as data-collection instruments. In each school, interviews were conducted with the school principal, teacher representatives serving on the school governing board, disciplinary committee members, and members of the representative council for learners. Disciplinary hearings and disciplinary committee meetings were observed, and documents of relevance to the study were reviewed. The findings, as reported on here, revealed that the code of conduct is the most important strategy that schools can use to enhance positive discipline. Other strategies in enhancing positive discipline include the use of a research-based positive classroom management approach; positive reinforcement; integrating community support services; modelling good behaviour; parental involvement; preventive, supportive and corrective discipline; detention; communication (incorporating professionalism and cooperation); the creation of an environment conducive to teaching and learning; and the withdrawal or withholding of privileges. The findings further revealed that positive discipline is an alternative to negative disciplinary measures, such as corporal punishment in schools. Teachers are expected to comply with, and adhere to, disciplinary policies, and to assist learners in unlearning bad behaviours and developing the necessary life skills, values, and attitudes. The participants’ understanding of the use of a code of conduct for positive discipline successfully assisted them, as teachers, in dealing with misbehaving learners, and, in turn, in developing learners’ positive self-control and self-esteem, helping them to become responsible citizens, and courageous and respectful learners, not only in the school environment, but also as members of society at large. The research findings also revealed that many participants believed using a code of conduct (positive discipline) to enhance positive behaviour was a waste of time, and ineffective. As the findings indicate, learners were found to become impervious or immune to positive disciplinary measures put in place to assist them with behavioural problems. The findings also revealed that the ineffectiveness of such a code in enhancing positive discipline could be attributed to the fact that the teachers themselves were not, to a certain degree, fully trained with regard to positive disciplinary measures. A lack of parental support and teacher professionalism, the continued use of (the prohibited) corporal punishment, poor communication, a lack of stakeholder involvement in formulating codes of conduct, a lack of positive modelling and power struggles were found to impede the use of a code of conduct to enhance positive discipline in schools. Based on the research findings, the study recommends that schools ensure that there is a sufficiently detailed code of conduct to assist teachers in addressing learners’ bad behaviour. There should also be advocacy from the Department of Basic Education, for support programmes to be put in place to assist teachers with alternative ways of enhancing positive discipline in the classroom. Awareness of how teachers are to be upskilled as regards positive disciplinary strategies, active parental involvement, and increased support for teachers, are amongst the recommendations. Ultimately, the researcher concluded that the code of conduct was a strategy that schools can use to enhance positive discipline. To this end, teachers must adhere to that code (and other positive disciplinary measures), for positive discipline to flourish in schools. , Thesis (PhD) -- Faculty of Education, 2022
- Full Text:
- Date Issued: 2022-03
- Authors: Zondo, Sindiswa Silindokuhle
- Date: 2022-03
- Subjects: School discipline
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21711 , vital:51744
- Description: Dealing with misbehaving learners remains a significant challenge for teachers in South African schools. As the use of corporal punishment and other punitive measures to deal with misbehaving learners is now illegal, alternative positive disciplinary measures have been put in place. The prohibition of negative disciplinary measures has left teachers feeling powerless and frustrated, not knowing how to manage learner behaviour, despite the fact that they are the viable agents tasked with ensuring that positive disciplinary measures are implemented in schools. This study sought to examine how best a code of conduct for learners can be used to enhance positive discipline in schools. To that end, the study offers insights into how positive disciplinary measures may be used, in dealing with learner indiscipline. This is a qualitative study, underpinned by the interpretivist paradigm. The study employed a phenomenological design as a strategy for data collection, to examine how a code of conduct for learners can be used to enhance positive discipline in selected township schools. As this is a qualitative study concerned more with the depth than the breadth of information, the researcher deemed it necessary to focus on two schools, to obtain deep insight into the participants’ lived experiences. Two schools, in Pinetown in Durban, participated in the study. Interviews, observations and document reviews were used as data-collection instruments. In each school, interviews were conducted with the school principal, teacher representatives serving on the school governing board, disciplinary committee members, and members of the representative council for learners. Disciplinary hearings and disciplinary committee meetings were observed, and documents of relevance to the study were reviewed. The findings, as reported on here, revealed that the code of conduct is the most important strategy that schools can use to enhance positive discipline. Other strategies in enhancing positive discipline include the use of a research-based positive classroom management approach; positive reinforcement; integrating community support services; modelling good behaviour; parental involvement; preventive, supportive and corrective discipline; detention; communication (incorporating professionalism and cooperation); the creation of an environment conducive to teaching and learning; and the withdrawal or withholding of privileges. The findings further revealed that positive discipline is an alternative to negative disciplinary measures, such as corporal punishment in schools. Teachers are expected to comply with, and adhere to, disciplinary policies, and to assist learners in unlearning bad behaviours and developing the necessary life skills, values, and attitudes. The participants’ understanding of the use of a code of conduct for positive discipline successfully assisted them, as teachers, in dealing with misbehaving learners, and, in turn, in developing learners’ positive self-control and self-esteem, helping them to become responsible citizens, and courageous and respectful learners, not only in the school environment, but also as members of society at large. The research findings also revealed that many participants believed using a code of conduct (positive discipline) to enhance positive behaviour was a waste of time, and ineffective. As the findings indicate, learners were found to become impervious or immune to positive disciplinary measures put in place to assist them with behavioural problems. The findings also revealed that the ineffectiveness of such a code in enhancing positive discipline could be attributed to the fact that the teachers themselves were not, to a certain degree, fully trained with regard to positive disciplinary measures. A lack of parental support and teacher professionalism, the continued use of (the prohibited) corporal punishment, poor communication, a lack of stakeholder involvement in formulating codes of conduct, a lack of positive modelling and power struggles were found to impede the use of a code of conduct to enhance positive discipline in schools. Based on the research findings, the study recommends that schools ensure that there is a sufficiently detailed code of conduct to assist teachers in addressing learners’ bad behaviour. There should also be advocacy from the Department of Basic Education, for support programmes to be put in place to assist teachers with alternative ways of enhancing positive discipline in the classroom. Awareness of how teachers are to be upskilled as regards positive disciplinary strategies, active parental involvement, and increased support for teachers, are amongst the recommendations. Ultimately, the researcher concluded that the code of conduct was a strategy that schools can use to enhance positive discipline. To this end, teachers must adhere to that code (and other positive disciplinary measures), for positive discipline to flourish in schools. , Thesis (PhD) -- Faculty of Education, 2022
- Full Text:
- Date Issued: 2022-03