Valorization of chicken feather through dekeratinization by keratinolytic Bacillus species to amino acid
- Authors: Matches, Lupho
- Date: 2021-02
- Subjects: Proteolytic enzymes , Poultry -- Processing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20451 , vital:45667
- Description: The poultry meat processing sector generates chicken feathers as by-products, and they are 90percent keratin in composition. Keratin is an insoluble and structural protein that shows recalcitrance to hydrolysis by classical proteolytic enzymes, including trypsin, pepsin, and papain. Keratinases are a group of proteolytic enzymes endowed with keratin degradation into peptides and amino acids. They are recently gaining traction for their multifaceted potential application in the green industrial space. Hence, keratinolytic bacteria previously isolated from dumpsite were identified using 16S rDNA sequencing. The optimal fermentation conditions were determined for enhanced extracellular keratinase production and chicken feather degradation. Also, the amino acid analysis of the chicken feather hydrolysates was carried out. The biochemical properties of the keratinases were also determined. Based on 16S rDNA sequencing and phylogenetic analysis, the isolates coded as SSN-02 and HSN-03 showed a high percentage of sequence homology with Bacillus spp.; hence, they were identified as Bacillus sp. NFH5 and Bacillus sp. FHNM, respectively. Bacillus sp. NFH5 showed optimal keratinase production of 1149.99 ± 80.99 U/mL after 96 h of incubation time, in optimized fermentation conditions that included pH (4.0), chicken feather (1.5percent, w/v), inoculum size (3percent, v/v) and temperature (30 oC). Similarly, Bacillus sp. FHNM demonstrated the maximum keratinase production of 480 ± 41.14 U/mL 144 h post cultivation, in optimized fermentation conditions with pH (7.0), chicken feather (2.0percent, w/v), inoculum size (3percent, v/v) and temperature (30 oC). For Bacillus sp. NFH5 chicken feather hydrolysate, the amino acids in relatively higher concentration (>1.0g/100g sample) include arginine (1.8), serine (1.16), aspartic acid (1.95), glutamic acid (2.47), proline (1.16) and glycine (1.45). Bacillus sp. FHNM feather hydrolysates, contained (g/100g of sample): arginine (1.9), serine (1.4), aspartic acid (2.5), glutamic acid (2.51), glycine (1.51), proline (1.13), leucine (1.030, histidine (1.25), and lysine (1.06) (g/100g of sample) in high concentration. The keratinases were optimally active at pH 8.0. Bacillus sp. FHNM showed an optimal temperature of 100 oC; while Bacillus sp. NFH5 keratinase displayed optimal activity at 90 oC. EDTA and 1,10-phenanthroline inhibited the keratinases, and the inhibition pattern indicated that they belong to metalloprotease. Keratinase from Bacillus sp. FHNM showed considerable residual activity in the presence of Co²⁺ (93percent), Fe³⁺ (99percent), and K⁺ (94percent). Bacillus sp. NFH5 keratinase retained 92percent, 92percent, 93percent of the original activity against Ba²⁺, Na⁺ and Fe³⁺ treatment. Bacillus sp. FHNM keratinase was remarkably stable after 60 min of detergents treatment with residual activity of 89percent, 96percent, 81percent, 73percent, 96percent, 88percent, 88percent and 98percent for Omo, Surf, Ariel, Sunlight, Prowash, Freshwave, Sky, and Evaklin, respectively. Maq impacted the enzyme stability negatively, with residual activity of 48percent after 60 min of incubation. Additionally, keratinase Bacillus sp. NFH5 retained 68percent, 78percent, 80percent, 84percent, 57percent, 80percent, 98percent, 106percent and 106percent of the original activity against Omo, Surf, Ariel, Sunlight, Maq, Prowash, Freshwave, Sky and Evaklin, respectively. Therefore, these results suggest that Bacillus spp. could be ideal candidates for sustainable production of active keratinases and valorization of the abundantly generated keratinous biomass. The stability displayed by keratinases from Bacillus sp. FHNM and Bacillus sp. NFH5 suggests their promising candidacy for detergent formulation. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-02
- Authors: Matches, Lupho
- Date: 2021-02
- Subjects: Proteolytic enzymes , Poultry -- Processing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20451 , vital:45667
- Description: The poultry meat processing sector generates chicken feathers as by-products, and they are 90percent keratin in composition. Keratin is an insoluble and structural protein that shows recalcitrance to hydrolysis by classical proteolytic enzymes, including trypsin, pepsin, and papain. Keratinases are a group of proteolytic enzymes endowed with keratin degradation into peptides and amino acids. They are recently gaining traction for their multifaceted potential application in the green industrial space. Hence, keratinolytic bacteria previously isolated from dumpsite were identified using 16S rDNA sequencing. The optimal fermentation conditions were determined for enhanced extracellular keratinase production and chicken feather degradation. Also, the amino acid analysis of the chicken feather hydrolysates was carried out. The biochemical properties of the keratinases were also determined. Based on 16S rDNA sequencing and phylogenetic analysis, the isolates coded as SSN-02 and HSN-03 showed a high percentage of sequence homology with Bacillus spp.; hence, they were identified as Bacillus sp. NFH5 and Bacillus sp. FHNM, respectively. Bacillus sp. NFH5 showed optimal keratinase production of 1149.99 ± 80.99 U/mL after 96 h of incubation time, in optimized fermentation conditions that included pH (4.0), chicken feather (1.5percent, w/v), inoculum size (3percent, v/v) and temperature (30 oC). Similarly, Bacillus sp. FHNM demonstrated the maximum keratinase production of 480 ± 41.14 U/mL 144 h post cultivation, in optimized fermentation conditions with pH (7.0), chicken feather (2.0percent, w/v), inoculum size (3percent, v/v) and temperature (30 oC). For Bacillus sp. NFH5 chicken feather hydrolysate, the amino acids in relatively higher concentration (>1.0g/100g sample) include arginine (1.8), serine (1.16), aspartic acid (1.95), glutamic acid (2.47), proline (1.16) and glycine (1.45). Bacillus sp. FHNM feather hydrolysates, contained (g/100g of sample): arginine (1.9), serine (1.4), aspartic acid (2.5), glutamic acid (2.51), glycine (1.51), proline (1.13), leucine (1.030, histidine (1.25), and lysine (1.06) (g/100g of sample) in high concentration. The keratinases were optimally active at pH 8.0. Bacillus sp. FHNM showed an optimal temperature of 100 oC; while Bacillus sp. NFH5 keratinase displayed optimal activity at 90 oC. EDTA and 1,10-phenanthroline inhibited the keratinases, and the inhibition pattern indicated that they belong to metalloprotease. Keratinase from Bacillus sp. FHNM showed considerable residual activity in the presence of Co²⁺ (93percent), Fe³⁺ (99percent), and K⁺ (94percent). Bacillus sp. NFH5 keratinase retained 92percent, 92percent, 93percent of the original activity against Ba²⁺, Na⁺ and Fe³⁺ treatment. Bacillus sp. FHNM keratinase was remarkably stable after 60 min of detergents treatment with residual activity of 89percent, 96percent, 81percent, 73percent, 96percent, 88percent, 88percent and 98percent for Omo, Surf, Ariel, Sunlight, Prowash, Freshwave, Sky, and Evaklin, respectively. Maq impacted the enzyme stability negatively, with residual activity of 48percent after 60 min of incubation. Additionally, keratinase Bacillus sp. NFH5 retained 68percent, 78percent, 80percent, 84percent, 57percent, 80percent, 98percent, 106percent and 106percent of the original activity against Omo, Surf, Ariel, Sunlight, Maq, Prowash, Freshwave, Sky and Evaklin, respectively. Therefore, these results suggest that Bacillus spp. could be ideal candidates for sustainable production of active keratinases and valorization of the abundantly generated keratinous biomass. The stability displayed by keratinases from Bacillus sp. FHNM and Bacillus sp. NFH5 suggests their promising candidacy for detergent formulation. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-02
Waste keratinous biomass valorization and characterization of keratinases produced by exiguobacteria species
- Authors: Dlume, Tutuka
- Date: 2021-02
- Subjects: Factory and trade waste -- Biodegradation , Bioremediation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20695 , vital:46438
- Description: Keratinous wastes are emanating in a million tons, as by-products, from various agro-industrial processing plants. Consequently, they create a serious solid waste problem in the environment due to poor handling. Microbial keratinases are proteolytic enzymes that effectively participate in keratin-rich biomass hydrolyses such as feathers, nail, hair, hooves, and horns. Therefore, proper management of these wastes via recycling into useful products is ecologically imperative. Biodegradation of keratin-rich biomass has been identified as an economical and environmentally friendly way of transforming these recalcitrant agro wastes into useful products, hence the motivation for this study. Feather degrading bacterial strains previously isolated from a municipal dumpsite and coded as SSB-02 and SSB-03 was identified through 16S rDNA sequencing and phylogenetic analysis. The fermentation conditions for keratinase production were optimized. The protein and amino acids constituents of the hydrolyzed chicken feather were analyzed. The biochemical properties of the keratinase produced were determined. Also, the effect of laundry detergents on the stability of the keratinase was studied. The isolates coded as SSB-02 and SSB-03 showed a high percentage of sequence homology with Exguobacterium spp., hence they were identified as Exiguobacterium sp. FBH5 and Exiguobacterium acetylicum FHBD, respectively. Exiguobacterium sp. FBH5 showed the highest extracellular keratinase production of 934.58 ± 27.27 U/mL at 72 h of incubation; in optimized fermentation conditions that included pH (5.0), temperature (30 oC), and chicken feather (0.5percent, w/v). Similarly, E. acetylicum FHBD displayed optimal keratinase production of 1023.64 ± 25.71 U/mL at 120 h of fermentation and improved fermentation conditions that involved pH (3.0), temperature (35 oC) and chicken feathers (0.5-1.5percent; w/v). The amino acid analysis showed that arginine, aspartic acid and glutamic acid were the most abundant amino acids cleaved from the degradation of chicken feathers by Exiguobacterium sp. FBH5 at a respective concentration of 1.16, 1.28 and 1.45 (g/100g sample). Additionally, hydrolysate that emanated from E. indicum FHBD degradation of feather showed high concentrations of arginine, serine, aspartic acid, glutamic acid, and glycine at the respective concentration (g/100g sample) of 1.2, 1.12, 1.34, 1.58 and 1.29. The keratinases were optimally active at pH and temperature of 8.0 and 50 oC, respectively. EDTA and PMSF did not highly repress keratinolytic proteases' activity, and this inhibitory pattern suggests that they may belong to a mixed protease family. Keratinase from E. acetylicum FHBD was highly stable in the presence of SDS, with 99percent residual activity and displayed variable stability in other chemical agents tested. A similar stability pattern was observed with keratinase from Exiguobacterium sp. FBH5, although the enzyme lost about 40percent of its original activity in the presence of SDS. Evaluation of metal ion stability indicated that E. acetylicum FHBD keratinase was remarkably stable in the presence of Fe3+, Mg2+, Cu2+, Zn2+, and Ba2+, with residual activity of 94percent, 88percent, 89percent, 90percent, and 97percent, respectively. Similarly, Exiguobacterium sp. FBH5 keratinase was considerably stable after treatment with Co2+, K+, and Zn2+ as it displayed a residual activity of 85percent, 84percent and 93percent, respectively. The study of the keratinases stability in laundry detergents showed that E. acetylicum FHBD keratinolytic proteases was activated in the presence of Omo, Surf, Sunlight, and Pro wash after 60 min of pre-incubation compared to 30 min, with residual activity of 94 ± 2.94percent, 91 ± 2.53percent, 95 ± 2.89percent and 87 ± 2.89percent respectively. Likewise, Exiguobacterium sp. FBH5 keratinase activity was promoted after 60 min of incubation compared to 30 min, with a residual enzyme activity of 79percent, 84percent, 101percent, 103percent and 105percent and 106percent for Ariel, Surf, Prowash, Freewave, Sky and Evaklin, respectively. Therefore Exiguobacterium spp., demonstrated excellent keratinolytic potentials that could be exploited for sustainable development of bio-innovative products. The study keratinases' properties suggest their industrial and biotechnological application potentials, especially as bio-additive in the formulation of laundry detergents. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-02
- Authors: Dlume, Tutuka
- Date: 2021-02
- Subjects: Factory and trade waste -- Biodegradation , Bioremediation
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20695 , vital:46438
- Description: Keratinous wastes are emanating in a million tons, as by-products, from various agro-industrial processing plants. Consequently, they create a serious solid waste problem in the environment due to poor handling. Microbial keratinases are proteolytic enzymes that effectively participate in keratin-rich biomass hydrolyses such as feathers, nail, hair, hooves, and horns. Therefore, proper management of these wastes via recycling into useful products is ecologically imperative. Biodegradation of keratin-rich biomass has been identified as an economical and environmentally friendly way of transforming these recalcitrant agro wastes into useful products, hence the motivation for this study. Feather degrading bacterial strains previously isolated from a municipal dumpsite and coded as SSB-02 and SSB-03 was identified through 16S rDNA sequencing and phylogenetic analysis. The fermentation conditions for keratinase production were optimized. The protein and amino acids constituents of the hydrolyzed chicken feather were analyzed. The biochemical properties of the keratinase produced were determined. Also, the effect of laundry detergents on the stability of the keratinase was studied. The isolates coded as SSB-02 and SSB-03 showed a high percentage of sequence homology with Exguobacterium spp., hence they were identified as Exiguobacterium sp. FBH5 and Exiguobacterium acetylicum FHBD, respectively. Exiguobacterium sp. FBH5 showed the highest extracellular keratinase production of 934.58 ± 27.27 U/mL at 72 h of incubation; in optimized fermentation conditions that included pH (5.0), temperature (30 oC), and chicken feather (0.5percent, w/v). Similarly, E. acetylicum FHBD displayed optimal keratinase production of 1023.64 ± 25.71 U/mL at 120 h of fermentation and improved fermentation conditions that involved pH (3.0), temperature (35 oC) and chicken feathers (0.5-1.5percent; w/v). The amino acid analysis showed that arginine, aspartic acid and glutamic acid were the most abundant amino acids cleaved from the degradation of chicken feathers by Exiguobacterium sp. FBH5 at a respective concentration of 1.16, 1.28 and 1.45 (g/100g sample). Additionally, hydrolysate that emanated from E. indicum FHBD degradation of feather showed high concentrations of arginine, serine, aspartic acid, glutamic acid, and glycine at the respective concentration (g/100g sample) of 1.2, 1.12, 1.34, 1.58 and 1.29. The keratinases were optimally active at pH and temperature of 8.0 and 50 oC, respectively. EDTA and PMSF did not highly repress keratinolytic proteases' activity, and this inhibitory pattern suggests that they may belong to a mixed protease family. Keratinase from E. acetylicum FHBD was highly stable in the presence of SDS, with 99percent residual activity and displayed variable stability in other chemical agents tested. A similar stability pattern was observed with keratinase from Exiguobacterium sp. FBH5, although the enzyme lost about 40percent of its original activity in the presence of SDS. Evaluation of metal ion stability indicated that E. acetylicum FHBD keratinase was remarkably stable in the presence of Fe3+, Mg2+, Cu2+, Zn2+, and Ba2+, with residual activity of 94percent, 88percent, 89percent, 90percent, and 97percent, respectively. Similarly, Exiguobacterium sp. FBH5 keratinase was considerably stable after treatment with Co2+, K+, and Zn2+ as it displayed a residual activity of 85percent, 84percent and 93percent, respectively. The study of the keratinases stability in laundry detergents showed that E. acetylicum FHBD keratinolytic proteases was activated in the presence of Omo, Surf, Sunlight, and Pro wash after 60 min of pre-incubation compared to 30 min, with residual activity of 94 ± 2.94percent, 91 ± 2.53percent, 95 ± 2.89percent and 87 ± 2.89percent respectively. Likewise, Exiguobacterium sp. FBH5 keratinase activity was promoted after 60 min of incubation compared to 30 min, with a residual enzyme activity of 79percent, 84percent, 101percent, 103percent and 105percent and 106percent for Ariel, Surf, Prowash, Freewave, Sky and Evaklin, respectively. Therefore Exiguobacterium spp., demonstrated excellent keratinolytic potentials that could be exploited for sustainable development of bio-innovative products. The study keratinases' properties suggest their industrial and biotechnological application potentials, especially as bio-additive in the formulation of laundry detergents. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-02
A new species of Buyisa Distant, 1907 (Hemiptera Cicadidae Cicadettinae Cicadettini) from South Africa
- Sanborn, Allen F, Villet, Martin H
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441318 , vital:73877 , https://doi.org/10.4289/0013-8797.123.1.199
- Description: A new species of the cicada genus Buyisa Distant, 1907 is described from South Africa for an undetermined species referenced in the literature. Buyisa eccaensis new species is described and illustrated and notes on its biology are provided. A key to the officially described species of Buyisa is also included.
- Full Text:
- Date Issued: 2021
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441318 , vital:73877 , https://doi.org/10.4289/0013-8797.123.1.199
- Description: A new species of the cicada genus Buyisa Distant, 1907 is described from South Africa for an undetermined species referenced in the literature. Buyisa eccaensis new species is described and illustrated and notes on its biology are provided. A key to the officially described species of Buyisa is also included.
- Full Text:
- Date Issued: 2021
Accelerated implementations of the RIME for DDE calibration and source modelling
- Authors: Van Staden, Joshua
- Date: 2021
- Subjects: Radio astronomy , Radio inferometers , Radio inferometers -- Calibration , Radio astronomy -- Data processing , Radio inferometers -- Data processing , Radio inferometers -- Calibration -- Data processing
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/172422 , vital:42199
- Description: Second- and third-generation calibration methods filter out subtle effects in interferometer data, and therefore yield significantly higher dynamic ranges. The basis of these calibration techniques relies on building a model of the sky and corrupting it with models of the effects acting on the sources. The sensitivities of modern instruments call for more elaborate models to capture the level of detail that is required to achieve accurate calibration. This thesis implements two types of models to be used in for second- and third-generation calibration. The first model implemented is shapelets, which can be used to model radio source morphologies directly in uv space. The second model implemented is Zernike polynomials, which can be used to represent the primary beam of the antenna. We implement these models in the CODEX-AFRICANUS package and provide a set of unit tests for each model. Additionally, we compare our implementations against other methods of representing these objects and instrumental effects, namely NIFTY-GRIDDER against shapelets and a FITS-interpolation method against the Zernike polynomials. We find that to achieve sufficient accuracy, our implementation of the shapelet model has a higher runtime to that of the NIFTY-GRIDDER. However, the NIFTY-GRIDDER cannot simulate a component-based sky model while the shapelet model can. Additionally, the shapelet model is fully parametric, which allows for integration into a parameterised solver. We find that, while having a smaller memory footprint, our Zernike model has a greater computational complexity than that of the FITS-interpolated method. However, we find that the Zernike implementation has floating-point accuracy in its modelling, while the FITS-interpolated model loses some accuracy through the discretisation of the beam.
- Full Text:
- Date Issued: 2021
- Authors: Van Staden, Joshua
- Date: 2021
- Subjects: Radio astronomy , Radio inferometers , Radio inferometers -- Calibration , Radio astronomy -- Data processing , Radio inferometers -- Data processing , Radio inferometers -- Calibration -- Data processing
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/172422 , vital:42199
- Description: Second- and third-generation calibration methods filter out subtle effects in interferometer data, and therefore yield significantly higher dynamic ranges. The basis of these calibration techniques relies on building a model of the sky and corrupting it with models of the effects acting on the sources. The sensitivities of modern instruments call for more elaborate models to capture the level of detail that is required to achieve accurate calibration. This thesis implements two types of models to be used in for second- and third-generation calibration. The first model implemented is shapelets, which can be used to model radio source morphologies directly in uv space. The second model implemented is Zernike polynomials, which can be used to represent the primary beam of the antenna. We implement these models in the CODEX-AFRICANUS package and provide a set of unit tests for each model. Additionally, we compare our implementations against other methods of representing these objects and instrumental effects, namely NIFTY-GRIDDER against shapelets and a FITS-interpolation method against the Zernike polynomials. We find that to achieve sufficient accuracy, our implementation of the shapelet model has a higher runtime to that of the NIFTY-GRIDDER. However, the NIFTY-GRIDDER cannot simulate a component-based sky model while the shapelet model can. Additionally, the shapelet model is fully parametric, which allows for integration into a parameterised solver. We find that, while having a smaller memory footprint, our Zernike model has a greater computational complexity than that of the FITS-interpolated method. However, we find that the Zernike implementation has floating-point accuracy in its modelling, while the FITS-interpolated model loses some accuracy through the discretisation of the beam.
- Full Text:
- Date Issued: 2021
Adaptive network intrusion detection using optimised machine learning models
- Chindove, Hatitye E, Brown, Dane L
- Authors: Chindove, Hatitye E , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465634 , vital:76627 , xlink:href="https://www.researchgate.net/publication/358046953_Adaptive_Network_Intrusion_Detection_using_Optimised_Machine_Learning_Models"
- Description: Network intrusion detection system (NIDS) adoption is essential for mitigating computer network attacks in various scenarios. However, the increasing complexity of computer networks and attacks make it challenging to classify network traffic. Machine learning (ML) techniques in a NIDS can be affected by different scenarios, and thus the recency, size and applicability of datasets are vital factors to consider when selecting and tuning a machine learning classifier. The proposed approach evaluates relatively new datasets constructed such that they depict real-world scenarios. It includes empirical analyses of practical, systematic ML-based NIDS with significant network traffic for improved intrusion detection. A comparison between machine learning classifiers, including deep learning, form part of the evaluation process. Results on how the proposed approach increased model effectiveness for NIDS in a more practical setting are discussed. Recurrent neural networks and random forests models consistently achieved the best results.
- Full Text:
- Date Issued: 2021
- Authors: Chindove, Hatitye E , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465634 , vital:76627 , xlink:href="https://www.researchgate.net/publication/358046953_Adaptive_Network_Intrusion_Detection_using_Optimised_Machine_Learning_Models"
- Description: Network intrusion detection system (NIDS) adoption is essential for mitigating computer network attacks in various scenarios. However, the increasing complexity of computer networks and attacks make it challenging to classify network traffic. Machine learning (ML) techniques in a NIDS can be affected by different scenarios, and thus the recency, size and applicability of datasets are vital factors to consider when selecting and tuning a machine learning classifier. The proposed approach evaluates relatively new datasets constructed such that they depict real-world scenarios. It includes empirical analyses of practical, systematic ML-based NIDS with significant network traffic for improved intrusion detection. A comparison between machine learning classifiers, including deep learning, form part of the evaluation process. Results on how the proposed approach increased model effectiveness for NIDS in a more practical setting are discussed. Recurrent neural networks and random forests models consistently achieved the best results.
- Full Text:
- Date Issued: 2021
Advancing Assessment Thinking in Education for Sustainable Development with a Focus on Significant Learning Processes
- Shumba, Overson, Mandikonza, Caleb, Lotz-Sisitka, Heila
- Authors: Shumba, Overson , Mandikonza, Caleb , Lotz-Sisitka, Heila
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435209 , vital:73138 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: This position paper is developed in the context of the Fundisa [Teaching] for Change teacher education programme (www.fundisaforchange.co.za), as well as the Sustainability Starts with Teachers programmes for teacher education (www. sustainabilityteachers.org/course). Fundisa for Change is a South African programme while Sustainability Starts with Teachers is a Southern Africa Development Community (SADC) programme for teacher educators. Both these programmes seek to enhance transformative environments and sustainability education processes in teacher education. They have a strategic focus on situated and transformative learning approaches for learners to learn to ‘know the world’ and practice ‘being in the world’. The real world provides the context for learning and assessment for learning, but not enough is known about assessment of such learning.
- Full Text:
- Date Issued: 2021
- Authors: Shumba, Overson , Mandikonza, Caleb , Lotz-Sisitka, Heila
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435209 , vital:73138 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: This position paper is developed in the context of the Fundisa [Teaching] for Change teacher education programme (www.fundisaforchange.co.za), as well as the Sustainability Starts with Teachers programmes for teacher education (www. sustainabilityteachers.org/course). Fundisa for Change is a South African programme while Sustainability Starts with Teachers is a Southern Africa Development Community (SADC) programme for teacher educators. Both these programmes seek to enhance transformative environments and sustainability education processes in teacher education. They have a strategic focus on situated and transformative learning approaches for learners to learn to ‘know the world’ and practice ‘being in the world’. The real world provides the context for learning and assessment for learning, but not enough is known about assessment of such learning.
- Full Text:
- Date Issued: 2021
Aluminum corrosion retardation properties of acetamidophenoxy phthalocyanines: Effect of central metal
- Nnaji, Nnaemeka, Sen, Pinar, Nyokong, Tebello
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
- Date Issued: 2021
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185433 , vital:44386 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.130806"
- Description: Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for metal free (2), ClGa (3) and Co (4) tetrakis (4-acetamidophenoxy) phthalocyanine. Electrochemical techniques were used in the study and complemented with Fourier transform infrared, scanning electron microscopy and X-ray diffraction measurements. Potentiodynamic polarization technique gave inhibition efficiency values as 93.3% (2), 69.7% (3) and 87.7% (4) at 28°C at highest inhibitor concentration (10 µM) in the following order 2 > 4 > 3. These compounds exhibited good corrosion inhibition performance as mixed-type corrosion inhibitors. All applied techniques gave results which corroborated.
- Full Text:
- Date Issued: 2021
Amphiphilic axially modified cationic indium-porphyrins linked to hydrophilic magnetic nanoparticles for photodynamic antimicrobial chemotherapy against gram-negative strain; Escherichia coli
- Makolla, Collen L, Mgidlana, Sithi, Nyokong, Tebello
- Authors: Makolla, Collen L , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185024 , vital:44317 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109262"
- Description: In this study, we report on the synthesis, characterization, and application of indium porphyrins linked to silver core-shell magnetic nanoparticles for in vitro photodynamic antimicrobial chemotherapy (PACT) against gram-negative strain, E. coli. This work compares the photophysicochemical and PACT activities of InCl 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridinium)-triiodide porphyrin (1), InCl 5-p-carboxyphenyl-10-15-20-(tris-4-hexylpyridinium)-triiodide porphyrin (2), In (para-aminophenyl) 5,10,15,20-tetrakis(4-methylpyridinium)-tetraiodide porphyrin (3), and In (para-aminophenyl) 5,10,15,20-tetrakis(4-hexylpyridinium)-tetraiodide porphyrin (4). The comparisons were based on the structure and number of charges. Hydrophilic and hydrophobic characters of the amphiphilic porphyrins were studied by comparing the effect of the different alkyl halides (iodomethane and iodohexane) quaternizing agents. The porphyrin complexes were further linked to magnetic nanoparticles to facilitate antimicrobial synergy and recovery of the complexes after use. High Log reduction values ranging from 7.19 to 9.58 were obtained for the quaternized complexes.
- Full Text:
- Date Issued: 2021
- Authors: Makolla, Collen L , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185024 , vital:44317 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109262"
- Description: In this study, we report on the synthesis, characterization, and application of indium porphyrins linked to silver core-shell magnetic nanoparticles for in vitro photodynamic antimicrobial chemotherapy (PACT) against gram-negative strain, E. coli. This work compares the photophysicochemical and PACT activities of InCl 5-p-carboxyphenyl-10-15-20-(tris-4-methylpyridinium)-triiodide porphyrin (1), InCl 5-p-carboxyphenyl-10-15-20-(tris-4-hexylpyridinium)-triiodide porphyrin (2), In (para-aminophenyl) 5,10,15,20-tetrakis(4-methylpyridinium)-tetraiodide porphyrin (3), and In (para-aminophenyl) 5,10,15,20-tetrakis(4-hexylpyridinium)-tetraiodide porphyrin (4). The comparisons were based on the structure and number of charges. Hydrophilic and hydrophobic characters of the amphiphilic porphyrins were studied by comparing the effect of the different alkyl halides (iodomethane and iodohexane) quaternizing agents. The porphyrin complexes were further linked to magnetic nanoparticles to facilitate antimicrobial synergy and recovery of the complexes after use. High Log reduction values ranging from 7.19 to 9.58 were obtained for the quaternized complexes.
- Full Text:
- Date Issued: 2021
An evaluation of co-management practices: A case of a South African platinum mine management and the local community
- Authors: Matsimela, Tebogo Mapipi
- Date: 2021
- Subjects: Mines and mineral resource -- Management -- South Africa , Mines and mineral resource -- Management -- Social aspects , Mines and mineral resource -- Management -- Moral and ethical aspects , Platinum mines and mining -- Management -- South Africa -- Case studies , Corporate governance -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/171874 , vital:42134
- Description: A vast body of literature reveals the paradigm shift of South Africa’s economy from an agricultural community to an industrial economy. Elbra (2013) illustrated that South African mining host communities viewed that mineral endowments have become a “resource curse” instead of a driver of local economic development for the benefit of the community. To understand the mining and community conflict and their subsequent complexities, the Marikana massacre in August 2012 must be revisited (Bell, 2016). The problems may be broadly summarised as a lack of stakeholder engagement and inclusivity. Studies involving stakeholder management and co-management focused on the identification of stakeholders and their management. The research evaluated the co-management practices between mine management and a local community. It considered the challenges that emanated from the co-management practices. The primary focus of this research has been to evaluate the co-management features between the mine management and the local community and to identify the challenges associated with co-management from a mine management perspective. Furthermore, the research attempted to find effective co-management practices between the mine management and the local community which may be used to improve the partnership. Armitage, Berkes and Doubleplay (2007) recognised that in facilitating effective co-management, the commitment towards fulfilling good governance and accountability was paramount in ensuring that the rights and obligations of both private and public actors were achieved. However, Ran and Qi (2018) acknowledged that such partnerships were not immune to challenges because the poor implementation of co-management features like power-sharing could collapse a co-management partnership. This study aimed to evaluate the current co-management practices from the mine management’s perspective. A literature search revealed the range of co-management features that explained the different use of practices. The features included co-management and power sharing, co-management and institution building, co-management and trust and social capital, co-management as a process, co-management and problem solving, and co-management and governance. The study evaluated the co-management features between the mine management and the local community, identified the current challenges associated with co-management from a mine management perspective and attempted to make recommendations on effective co-management practices between the mine management and a local community. A qualitative case study method was employed. This method allowed the researcher to evaluate multifaceted matters which may have been investigated in the past but not inconsiderable detail (Baxter and Jack, 2008). Data was sampled using purposive sampling. This was because the population sample was chosen according to their roles and responsibilities and their involvement in the co-management between the mine management and the local community. Data was collected through semi-structured interviews and document analyses. The findings of the research were derived from a range of company documents. Thematic analysis was employed to understand the practices of co-management which underpinned the co-management partnership between the mine management and the local community. It was found that there was a positive relationship between the literature study and the response from the mine management. The shared responsibilities emerged out of a dialogue characterised by deliberation and negotiations between the mine management and the stakeholders. Berkes (2009), asserted that co-management bore a resemblance to the process of the sharing of ideas of how responsibilities could be better shared and that it emanated from a process of deliberation and negotiation. Furthermore, if the evolution of the co-management partnership was not managed carefully, it could pose a risk to the partnership itself. It was acknowledged by the research respondents that there were complications involved in having the community as a shareholder in the mine, but equally, the community showed an appreciation of being involved in building a sustainable mine. The model of sustainable partnership emphasised that any viable partnership should adopt this model to achieve a sustainable performance (Thomson and Boutilier, 2011). This research showed that the co-management practices between the mine management and the local community concurred with the findings of Zvarivadza (2018). Trust and transparency between mine management and the community could go a long way in ensuring that the mine fulfilled its legal responsibilities in the local community where the mine is located.
- Full Text:
- Date Issued: 2021
- Authors: Matsimela, Tebogo Mapipi
- Date: 2021
- Subjects: Mines and mineral resource -- Management -- South Africa , Mines and mineral resource -- Management -- Social aspects , Mines and mineral resource -- Management -- Moral and ethical aspects , Platinum mines and mining -- Management -- South Africa -- Case studies , Corporate governance -- South Africa -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/171874 , vital:42134
- Description: A vast body of literature reveals the paradigm shift of South Africa’s economy from an agricultural community to an industrial economy. Elbra (2013) illustrated that South African mining host communities viewed that mineral endowments have become a “resource curse” instead of a driver of local economic development for the benefit of the community. To understand the mining and community conflict and their subsequent complexities, the Marikana massacre in August 2012 must be revisited (Bell, 2016). The problems may be broadly summarised as a lack of stakeholder engagement and inclusivity. Studies involving stakeholder management and co-management focused on the identification of stakeholders and their management. The research evaluated the co-management practices between mine management and a local community. It considered the challenges that emanated from the co-management practices. The primary focus of this research has been to evaluate the co-management features between the mine management and the local community and to identify the challenges associated with co-management from a mine management perspective. Furthermore, the research attempted to find effective co-management practices between the mine management and the local community which may be used to improve the partnership. Armitage, Berkes and Doubleplay (2007) recognised that in facilitating effective co-management, the commitment towards fulfilling good governance and accountability was paramount in ensuring that the rights and obligations of both private and public actors were achieved. However, Ran and Qi (2018) acknowledged that such partnerships were not immune to challenges because the poor implementation of co-management features like power-sharing could collapse a co-management partnership. This study aimed to evaluate the current co-management practices from the mine management’s perspective. A literature search revealed the range of co-management features that explained the different use of practices. The features included co-management and power sharing, co-management and institution building, co-management and trust and social capital, co-management as a process, co-management and problem solving, and co-management and governance. The study evaluated the co-management features between the mine management and the local community, identified the current challenges associated with co-management from a mine management perspective and attempted to make recommendations on effective co-management practices between the mine management and a local community. A qualitative case study method was employed. This method allowed the researcher to evaluate multifaceted matters which may have been investigated in the past but not inconsiderable detail (Baxter and Jack, 2008). Data was sampled using purposive sampling. This was because the population sample was chosen according to their roles and responsibilities and their involvement in the co-management between the mine management and the local community. Data was collected through semi-structured interviews and document analyses. The findings of the research were derived from a range of company documents. Thematic analysis was employed to understand the practices of co-management which underpinned the co-management partnership between the mine management and the local community. It was found that there was a positive relationship between the literature study and the response from the mine management. The shared responsibilities emerged out of a dialogue characterised by deliberation and negotiations between the mine management and the stakeholders. Berkes (2009), asserted that co-management bore a resemblance to the process of the sharing of ideas of how responsibilities could be better shared and that it emanated from a process of deliberation and negotiation. Furthermore, if the evolution of the co-management partnership was not managed carefully, it could pose a risk to the partnership itself. It was acknowledged by the research respondents that there were complications involved in having the community as a shareholder in the mine, but equally, the community showed an appreciation of being involved in building a sustainable mine. The model of sustainable partnership emphasised that any viable partnership should adopt this model to achieve a sustainable performance (Thomson and Boutilier, 2011). This research showed that the co-management practices between the mine management and the local community concurred with the findings of Zvarivadza (2018). Trust and transparency between mine management and the community could go a long way in ensuring that the mine fulfilled its legal responsibilities in the local community where the mine is located.
- Full Text:
- Date Issued: 2021
An Evaluation of Machine Learning Methods for Classifying Bot Traffic in Software Defined Networks
- Van Staden, Joshua, Brown, Dane L
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465645 , vital:76628 , xlink:href="https://link.springer.com/chapter/10.1007/978-981-19-7874-6_72"
- Description: Internet security is an ever-expanding field. Cyber-attacks occur very frequently, and so detecting them is an important aspect of preserving services. Machine learning offers a helpful tool with which to detect cyber attacks. However, it is impossible to deploy a machine-learning algorithm to detect attacks in a non-centralized network. Software Defined Networks (SDNs) offer a centralized view of a network, allowing machine learning algorithms to detect malicious activity within a network. The InSDN dataset is a recently-released dataset that contains a set of sniffed packets within a virtual SDN. These sniffed packets correspond to various attacks, including DDoS attacks, Probing and Password-Guessing, among others. This study aims to evaluate various machine learning models against this new dataset. Specifically, we aim to evaluate their classification ability and runtimes when trained on fewer features. The machine learning models tested include a Neural Network, Support Vector Machine, Random Forest, Multilayer Perceptron, Logistic Regression, and K-Nearest Neighbours. Cluster-based algorithms such as the K-Nearest Neighbour and Random Forest proved to be the best performers. Linear-based algorithms such as the Multilayer Perceptron performed the worst. This suggests a good level of clustering in the top few features with little space for linear separability. The reduction of features significantly reduced training time, particularly in the better-performing models.
- Full Text:
- Date Issued: 2021
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465645 , vital:76628 , xlink:href="https://link.springer.com/chapter/10.1007/978-981-19-7874-6_72"
- Description: Internet security is an ever-expanding field. Cyber-attacks occur very frequently, and so detecting them is an important aspect of preserving services. Machine learning offers a helpful tool with which to detect cyber attacks. However, it is impossible to deploy a machine-learning algorithm to detect attacks in a non-centralized network. Software Defined Networks (SDNs) offer a centralized view of a network, allowing machine learning algorithms to detect malicious activity within a network. The InSDN dataset is a recently-released dataset that contains a set of sniffed packets within a virtual SDN. These sniffed packets correspond to various attacks, including DDoS attacks, Probing and Password-Guessing, among others. This study aims to evaluate various machine learning models against this new dataset. Specifically, we aim to evaluate their classification ability and runtimes when trained on fewer features. The machine learning models tested include a Neural Network, Support Vector Machine, Random Forest, Multilayer Perceptron, Logistic Regression, and K-Nearest Neighbours. Cluster-based algorithms such as the K-Nearest Neighbour and Random Forest proved to be the best performers. Linear-based algorithms such as the Multilayer Perceptron performed the worst. This suggests a good level of clustering in the top few features with little space for linear separability. The reduction of features significantly reduced training time, particularly in the better-performing models.
- Full Text:
- Date Issued: 2021
An Evaluation of YOLO-Based Algorithms for Hand Detection in the Kitchen
- Van Staden, Joshua, Brown, Dane L
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465134 , vital:76576 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9519307"
- Description: Convolutional Neural Networks have offered an accurate method with which to run object detection on images. Specifically, the YOLO family of object detection algorithms have proven to be relatively fast and accurate. Since its inception, the different variants of this algorithm have been tested on different datasets. In this paper, we evaluate the performances of these algorithms on the recent Epic Kitchens-100 dataset. This dataset provides egocentric footage of people interacting with various objects in the kitchen. Most prominently shown in the footage is an egocentric view of the participants' hands. We aim to use the YOLOv3 algorithm to detect these hands within the footage provided in this dataset. In particular, we examine the YOLOv3 algorithm using two different backbones: MobileNet-lite and VGG16. We trained them on a mixture of samples from the Egohands and Epic Kitchens-100 datasets. In a separate experiment, average precision was measured on an unseen Epic Kitchens-100 subset. We found that the models are relatively simple and lead to lower scores on the Epic Kitchens 100 dataset. This is attributed to the high background noise on the Epic Kitchens 100 dataset. Nonetheless, the VGG16 architecture was found to have a higher Average Precision (AP) and is, therefore, more suited for retrospective analysis. None of the models was suitable for real-time analysis due to complex egocentric data.
- Full Text:
- Date Issued: 2021
- Authors: Van Staden, Joshua , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/465134 , vital:76576 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9519307"
- Description: Convolutional Neural Networks have offered an accurate method with which to run object detection on images. Specifically, the YOLO family of object detection algorithms have proven to be relatively fast and accurate. Since its inception, the different variants of this algorithm have been tested on different datasets. In this paper, we evaluate the performances of these algorithms on the recent Epic Kitchens-100 dataset. This dataset provides egocentric footage of people interacting with various objects in the kitchen. Most prominently shown in the footage is an egocentric view of the participants' hands. We aim to use the YOLOv3 algorithm to detect these hands within the footage provided in this dataset. In particular, we examine the YOLOv3 algorithm using two different backbones: MobileNet-lite and VGG16. We trained them on a mixture of samples from the Egohands and Epic Kitchens-100 datasets. In a separate experiment, average precision was measured on an unseen Epic Kitchens-100 subset. We found that the models are relatively simple and lead to lower scores on the Epic Kitchens 100 dataset. This is attributed to the high background noise on the Epic Kitchens 100 dataset. Nonetheless, the VGG16 architecture was found to have a higher Average Precision (AP) and is, therefore, more suited for retrospective analysis. None of the models was suitable for real-time analysis due to complex egocentric data.
- Full Text:
- Date Issued: 2021
An Examination of the Nexus between Environmental Knowledge and Environmental Learning Processes
- Chitsiga, Christina, Schudel, Ingrid J
- Authors: Chitsiga, Christina , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435086 , vital:73129 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: Previous chapters in this book have discussed the complexity of environmental content (see Schudel and Lotz-Sisitka, Chapter 2; Isaacs and Olvitt, Chapter 4) and Chapter 8 (Schudel) has highlighted the significance and key elements of active and critical approaches to learning. The primary purpose of this chapter is to draw these two approaches together; that is, to explore the nexus of environmental content and environmental learning processes.
- Full Text:
- Date Issued: 2021
- Authors: Chitsiga, Christina , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435086 , vital:73129 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: Previous chapters in this book have discussed the complexity of environmental content (see Schudel and Lotz-Sisitka, Chapter 2; Isaacs and Olvitt, Chapter 4) and Chapter 8 (Schudel) has highlighted the significance and key elements of active and critical approaches to learning. The primary purpose of this chapter is to draw these two approaches together; that is, to explore the nexus of environmental content and environmental learning processes.
- Full Text:
- Date Issued: 2021
An Exploration of what Grade 7 Natural Sciences Teachers Know, Believe and Say about Biodiversity and the Teaching of Biodiversity
- Isaacs, Dorelle, Olvitt, Lausanne L
- Authors: Isaacs, Dorelle , Olvitt, Lausanne L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435153 , vital:73134 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: This chapter shares the findings of a small-scale qualitative research project that investigated what three Grade 7 Natural Sciences teachers know, believe and say about biodiversity (Isaacs 2016). The study was sparked by the researcher’s interest in environmental learning and the importance of school curricula in preparing children to take care of their local and global environments. Biodiversity refers to Earth’s rich variety of plants and animals. It has been described as ‘the complex web of life’that includes diversity at genetic, species and ecosystem levels (Gurr et al. 2012: 4). The concept came to prominence in 1992 when the United Nations’ Convention on Biological Diversity defined biological diversity as ‘the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems’(United Nations 1992: Article 2).
- Full Text:
- Date Issued: 2021
- Authors: Isaacs, Dorelle , Olvitt, Lausanne L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435153 , vital:73134 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: This chapter shares the findings of a small-scale qualitative research project that investigated what three Grade 7 Natural Sciences teachers know, believe and say about biodiversity (Isaacs 2016). The study was sparked by the researcher’s interest in environmental learning and the importance of school curricula in preparing children to take care of their local and global environments. Biodiversity refers to Earth’s rich variety of plants and animals. It has been described as ‘the complex web of life’that includes diversity at genetic, species and ecosystem levels (Gurr et al. 2012: 4). The concept came to prominence in 1992 when the United Nations’ Convention on Biological Diversity defined biological diversity as ‘the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems’(United Nations 1992: Article 2).
- Full Text:
- Date Issued: 2021
An exploratory case study on the barriers, challenges and benefits of sustainability reporting by small and medium enterprises (SMEs) in South Africa
- Authors: Mhlope, Veliswa
- Date: 2021
- Subjects: Small business -- South Africa -- Case studies , Sustainable development reporting -- South Africa -- Case studies , Social responsibility of business , Environmental responsibility -- South Africa , Environmental reporting -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/172018 , vital:42149
- Description: SMEs in South Africa and other developing countries have been slow to take up sustainability reporting. This qualitative study is aimed to study the challenges and barriers faced by SMEs, together with the potential benefits for SMEs participating in this type of reporting. It also makes recommendations about how SMEs can participate in and benefit from sustainability reporting. The study shows that indeed there are several challenges in terms of getting involved in sustainability reporting for SMEs. On the other hand, the research finds that the SMEs who are already participating in sustainability reporting can show the benefits of engaging in sustainability reporting and that these benefits far outweigh the challenges. The participating SMEs are also able to show that they have attained a competitive advantage as a result of engaging in sustainability reporting. If, however, sustainability reporting is to become entrenched into SMEs, a few changes need to take place to address challenges such as lack of information about sustainability reporting and its benefits, lack of regulations and more importantly, lack of awareness about sustainable development. As the South African government begins to respond to issues such as climate change, skills development and good governance, it will become necessary for them to introduce regulations to manage this risk. It is also highly possible that in the next few years, reporting will become a regulatory requirement that SMEs will be forced to comply with to continue to do business. The SMEs who are already practising sustainability practices will benefit from being first movers. Those SMEs who start sooner rather than later will already have the internal resources and capabilities to take advantage of the legislative environment. They will have a head start over their rivals in terms of gaining competitive advantage.
- Full Text:
- Date Issued: 2021
- Authors: Mhlope, Veliswa
- Date: 2021
- Subjects: Small business -- South Africa -- Case studies , Sustainable development reporting -- South Africa -- Case studies , Social responsibility of business , Environmental responsibility -- South Africa , Environmental reporting -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/172018 , vital:42149
- Description: SMEs in South Africa and other developing countries have been slow to take up sustainability reporting. This qualitative study is aimed to study the challenges and barriers faced by SMEs, together with the potential benefits for SMEs participating in this type of reporting. It also makes recommendations about how SMEs can participate in and benefit from sustainability reporting. The study shows that indeed there are several challenges in terms of getting involved in sustainability reporting for SMEs. On the other hand, the research finds that the SMEs who are already participating in sustainability reporting can show the benefits of engaging in sustainability reporting and that these benefits far outweigh the challenges. The participating SMEs are also able to show that they have attained a competitive advantage as a result of engaging in sustainability reporting. If, however, sustainability reporting is to become entrenched into SMEs, a few changes need to take place to address challenges such as lack of information about sustainability reporting and its benefits, lack of regulations and more importantly, lack of awareness about sustainable development. As the South African government begins to respond to issues such as climate change, skills development and good governance, it will become necessary for them to introduce regulations to manage this risk. It is also highly possible that in the next few years, reporting will become a regulatory requirement that SMEs will be forced to comply with to continue to do business. The SMEs who are already practising sustainability practices will benefit from being first movers. Those SMEs who start sooner rather than later will already have the internal resources and capabilities to take advantage of the legislative environment. They will have a head start over their rivals in terms of gaining competitive advantage.
- Full Text:
- Date Issued: 2021
An exploratory study of psychologists’ perceptions of the phenomenon currently understood as ‘borderline personality disorder’
- Authors: Daya, Lekha
- Date: 2021
- Subjects: Borderline personality disorder , Psychologists -- Attitudes -- South Africa , Diagnostic and statistical manual of mental disorders
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/171139 , vital:42023
- Description: The phenomenon currently understood as ‘borderline personality disorder’ (BPD) has been complex and multifaceted since its inception. Previous studies have focused on the validity of The Diagnostic and Statistical Manual of Mental Disorders (DSM) conceptualisation of BPD, aetiologies of BPD, the psychologies of persons diagnosed with BPD, and the gendered nature of BPD. This study aimed to specifically explore South African practising psychologists’ perceptions of BPD. Through thematic analysis from a constructivist, post-modern paradigm, this study aimed to explore the perceptions and experiences of practising psychologists on BPD, as well as the usefulness of the DSM in working with BPD in a non-western society such as South Africa (SA). The study sampled two Counselling and two Clinical psychologists practising in the South African context, with exposure to and experience in working with BPD. Collectively, results in this study identified psychologists’ perceptions of shortcomings in the usefulness of the DSM’s approach to categorising phenomena associated with BPD, and brought attention to a need for further research and attention into the role of psychologists’ in the construction of BPD. This study seeks to represent psychologists’ practical experiences and perceptions, in an attempt to add contextually relevant findings on the DSM’s construction of BPD, and to contribute to challenging the stigma and misunderstanding associated with BPD. Specific practice implications and recommendations for future research are discussed within.
- Full Text:
- Date Issued: 2021
- Authors: Daya, Lekha
- Date: 2021
- Subjects: Borderline personality disorder , Psychologists -- Attitudes -- South Africa , Diagnostic and statistical manual of mental disorders
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/171139 , vital:42023
- Description: The phenomenon currently understood as ‘borderline personality disorder’ (BPD) has been complex and multifaceted since its inception. Previous studies have focused on the validity of The Diagnostic and Statistical Manual of Mental Disorders (DSM) conceptualisation of BPD, aetiologies of BPD, the psychologies of persons diagnosed with BPD, and the gendered nature of BPD. This study aimed to specifically explore South African practising psychologists’ perceptions of BPD. Through thematic analysis from a constructivist, post-modern paradigm, this study aimed to explore the perceptions and experiences of practising psychologists on BPD, as well as the usefulness of the DSM in working with BPD in a non-western society such as South Africa (SA). The study sampled two Counselling and two Clinical psychologists practising in the South African context, with exposure to and experience in working with BPD. Collectively, results in this study identified psychologists’ perceptions of shortcomings in the usefulness of the DSM’s approach to categorising phenomena associated with BPD, and brought attention to a need for further research and attention into the role of psychologists’ in the construction of BPD. This study seeks to represent psychologists’ practical experiences and perceptions, in an attempt to add contextually relevant findings on the DSM’s construction of BPD, and to contribute to challenging the stigma and misunderstanding associated with BPD. Specific practice implications and recommendations for future research are discussed within.
- Full Text:
- Date Issued: 2021
An investigation into the mediation of the representation of gender roles in God of women : a critical discourse analysis of pedagogic practices in selected Namibian schools
- Nghikefelwa, Josephine Mwasheka
- Authors: Nghikefelwa, Josephine Mwasheka
- Date: 2021
- Subjects: Nyati, Sifiso. God of women , Stereotypes (Social psychology) in literature , Women in literature , English literature -- Study and teaching (Secondary) -- Namibia , Women's rights in literature , Women's rights -- Study and teaching (Secondary)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172389 , vital:42195 , 10.21504/10962/172389
- Description: This is a qualitative study designed to investigate the role of pedagogical practices in the mediation of stereotypical gender representations in the drama God of Women by Sifiso Nyathi (1998). This drama is one of the literature setworks for Grade 9 English Second Language learners in Namibian Secondary schools. Fairclough’s (2012) Critical Discourse Analysis was used as a research design, as well as the conceptual and analytical framework. The analysis of this drama by teachers during the teaching and learning process, pedagogic practices they employ, learners’ engagement in classroom activities, and the nature of comments that teachers write on students’ assignment, based on God of Women, formed part of the unit of analysis. The study explored teachers’ pedagogical practices during English Literature teaching to gain insight into whether and how teachers shape learners’ engagement with literature to promote critical thinking. Focus on the mediation process (‘teacher talks around the text’) concerned a close analysis of teachers’ engagement with the text during lessons. Semi-structured interviews, classroom observation and documentary evidence were used to generate data. The research site and study participants were purposively sampled.
- Full Text:
- Date Issued: 2021
- Authors: Nghikefelwa, Josephine Mwasheka
- Date: 2021
- Subjects: Nyati, Sifiso. God of women , Stereotypes (Social psychology) in literature , Women in literature , English literature -- Study and teaching (Secondary) -- Namibia , Women's rights in literature , Women's rights -- Study and teaching (Secondary)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172389 , vital:42195 , 10.21504/10962/172389
- Description: This is a qualitative study designed to investigate the role of pedagogical practices in the mediation of stereotypical gender representations in the drama God of Women by Sifiso Nyathi (1998). This drama is one of the literature setworks for Grade 9 English Second Language learners in Namibian Secondary schools. Fairclough’s (2012) Critical Discourse Analysis was used as a research design, as well as the conceptual and analytical framework. The analysis of this drama by teachers during the teaching and learning process, pedagogic practices they employ, learners’ engagement in classroom activities, and the nature of comments that teachers write on students’ assignment, based on God of Women, formed part of the unit of analysis. The study explored teachers’ pedagogical practices during English Literature teaching to gain insight into whether and how teachers shape learners’ engagement with literature to promote critical thinking. Focus on the mediation process (‘teacher talks around the text’) concerned a close analysis of teachers’ engagement with the text during lessons. Semi-structured interviews, classroom observation and documentary evidence were used to generate data. The research site and study participants were purposively sampled.
- Full Text:
- Date Issued: 2021
An online information security Aaareness model: the disclosure of personal data
- Authors: Parker, Heather Joubert
- Date: 2021
- Subjects: Social media -- Psychological aspects , Social media -- Psychological aspects -- South Africa , Human behavior , Disclosure of information -- Psychological aspects -- Case studies , Personal information management -- Psychological aspects -- Case studies , Data protection -- Psychologial aspects -- Case studies
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/172329 , vital:42189
- Description: Social media has revolutionized the way people send and receive information by creating a new level of interconnected communication. However, the use of the Internet and social media brings about various ways in which a user’s personal data can be put at risk. This study aims to investigate what drives the disclosure of personal information online and whether an increase in awareness of the value of personal information motivates users to safeguard their information. Fourteen university students participated in a mixed-methods experiment, where they completed a questionnaire before and after being shown the data stored about them by online platforms to determine if changes occur in their intention to disclose. Following completing the initial questionnaire, the participant viewed the personal data stored about them by Facebook, Google, and Instagram. Other online tools such as Social Profile Checker, Facebook View As, and HaveIBeenPawned were used to see the information publicly available about each participant. Together these findings were discussed in a semi-structured interview to determine the influence of attitudes, subjective norms, and awareness on the cost-benefit analysis users conduct when disclosing information online. Overall, the findings indicate that users are able to disregard their concerns due to a resigned and apathetic attitude towards privacy. Furthermore, subjective norms enhanced by FOMO further allow users to overlook potential risks to their information in order to avoid social isolation and sanction. Alternatively, an increased awareness of the personal value of information and having experienced a previous privacy violation encourage the protection of information and limited disclosure. Thus, this study provides insight into privacy and information disclosure on social media in South Africa. It reveals more insight into the cost-benefit analysis users conduct by combining the Theory of Planned Behaviour with the Privacy Calculus Model, as well as the antecedent factors of Trust in the Social Media Provider, FOMO, and Personal Valuation of Information.
- Full Text:
- Date Issued: 2021
- Authors: Parker, Heather Joubert
- Date: 2021
- Subjects: Social media -- Psychological aspects , Social media -- Psychological aspects -- South Africa , Human behavior , Disclosure of information -- Psychological aspects -- Case studies , Personal information management -- Psychological aspects -- Case studies , Data protection -- Psychologial aspects -- Case studies
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/172329 , vital:42189
- Description: Social media has revolutionized the way people send and receive information by creating a new level of interconnected communication. However, the use of the Internet and social media brings about various ways in which a user’s personal data can be put at risk. This study aims to investigate what drives the disclosure of personal information online and whether an increase in awareness of the value of personal information motivates users to safeguard their information. Fourteen university students participated in a mixed-methods experiment, where they completed a questionnaire before and after being shown the data stored about them by online platforms to determine if changes occur in their intention to disclose. Following completing the initial questionnaire, the participant viewed the personal data stored about them by Facebook, Google, and Instagram. Other online tools such as Social Profile Checker, Facebook View As, and HaveIBeenPawned were used to see the information publicly available about each participant. Together these findings were discussed in a semi-structured interview to determine the influence of attitudes, subjective norms, and awareness on the cost-benefit analysis users conduct when disclosing information online. Overall, the findings indicate that users are able to disregard their concerns due to a resigned and apathetic attitude towards privacy. Furthermore, subjective norms enhanced by FOMO further allow users to overlook potential risks to their information in order to avoid social isolation and sanction. Alternatively, an increased awareness of the personal value of information and having experienced a previous privacy violation encourage the protection of information and limited disclosure. Thus, this study provides insight into privacy and information disclosure on social media in South Africa. It reveals more insight into the cost-benefit analysis users conduct by combining the Theory of Planned Behaviour with the Privacy Calculus Model, as well as the antecedent factors of Trust in the Social Media Provider, FOMO, and Personal Valuation of Information.
- Full Text:
- Date Issued: 2021
Anti-oxidant and cytotoxicity activity against the HCC70 Breast cancer cell line of aqueous and methanolic extracts of two red algae species from the Eastern Cape Coast, South Africa
- Authors: Basera, Afra Tsitsi
- Date: 2021
- Subjects: Drug resistance in cancer cells , Oxidative stress
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22589 , vital:52586
- Description: Cancer, despite extensive research, remains one of the leading causes of mortality. Research into plant-derived compounds has gained traction, as some are not cytotoxic towards healthy cells and pose fewer side effects. Marine algae produce secondary metabolites, protecting them from oxidative stress, which causes cardiovascular diseases, cancer, and diabetes. Therefore, this study aimed to evaluate the anticancer potential of selected red algae species, collected from Humewood Beach, Gqeberha in South Africa, against HCC70 (human breast adenocarcinoma) cancer cells. Identification of the species was made through DNA barcoding of the rbcL gene. Methanolic and aqueous extracts of Gelidium pristoides and Laurencia natalensis were evaluated for antioxidant activity, phytochemical content, and anticancer potential. The phytochemical composition was determined using the phenol, flavonoid, flavonol, tannin, and proanthocyanidin content assays. Antioxidant potential was evaluated using the Ferric reducing antioxidant potential, Diphenyl-1- Picrylhydrazyl (DPPH), nitric oxide, 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity, and total antioxidant capacity (TAC) assays. The resazurin assay was used to determine the antiproliferative and cytotoxic activity of the methanolic extracts and solid-phase extraction fractions against the HCC70 breast cancer cells. The red algae species were identified as G. pristoides and L. natalensis. The aqueous extract of G. pristoides exhibited significantly higher phenols (24.0 mg/g GAE), tannins (31.6 mg/g TAE), and flavonols content (20.5 mg/g RE) than its methanolic extract, or the aqueous and methanolic extracts of L. natalensis. Methanolic extracts of G. pristoides and L. natalensis exhibited significantly higher proanthocyanidin contents (19.4 mg/g and 15.7 mg/g CE) than their respective aqueous extracts (13.0 mg/g and 11.8 mg/g CE). Flavonoids, however, were absent in both species. The aqueous and methanol extracts of Laurencia natalensis and Gelidium pristoides exhibited low inhibitory activities (less than 50%) against DPPH, ABTS, and nitric oxide radicals. Both species also showed low ferric reducing power. All the extracts were antiproliferative and cytotoxic against the HCC70 breast cancer cells, with L. natalensis exhibiting more significant inhibitory activity. However, its Solid Phase Extraction fractions did not display antiproliferative potential, unlike fraction 4 of G. pristoides. The study results suggest that both G. pristoides and L. natalensis possess bioactive compounds with potential anticancer activity. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021
- Authors: Basera, Afra Tsitsi
- Date: 2021
- Subjects: Drug resistance in cancer cells , Oxidative stress
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22589 , vital:52586
- Description: Cancer, despite extensive research, remains one of the leading causes of mortality. Research into plant-derived compounds has gained traction, as some are not cytotoxic towards healthy cells and pose fewer side effects. Marine algae produce secondary metabolites, protecting them from oxidative stress, which causes cardiovascular diseases, cancer, and diabetes. Therefore, this study aimed to evaluate the anticancer potential of selected red algae species, collected from Humewood Beach, Gqeberha in South Africa, against HCC70 (human breast adenocarcinoma) cancer cells. Identification of the species was made through DNA barcoding of the rbcL gene. Methanolic and aqueous extracts of Gelidium pristoides and Laurencia natalensis were evaluated for antioxidant activity, phytochemical content, and anticancer potential. The phytochemical composition was determined using the phenol, flavonoid, flavonol, tannin, and proanthocyanidin content assays. Antioxidant potential was evaluated using the Ferric reducing antioxidant potential, Diphenyl-1- Picrylhydrazyl (DPPH), nitric oxide, 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity, and total antioxidant capacity (TAC) assays. The resazurin assay was used to determine the antiproliferative and cytotoxic activity of the methanolic extracts and solid-phase extraction fractions against the HCC70 breast cancer cells. The red algae species were identified as G. pristoides and L. natalensis. The aqueous extract of G. pristoides exhibited significantly higher phenols (24.0 mg/g GAE), tannins (31.6 mg/g TAE), and flavonols content (20.5 mg/g RE) than its methanolic extract, or the aqueous and methanolic extracts of L. natalensis. Methanolic extracts of G. pristoides and L. natalensis exhibited significantly higher proanthocyanidin contents (19.4 mg/g and 15.7 mg/g CE) than their respective aqueous extracts (13.0 mg/g and 11.8 mg/g CE). Flavonoids, however, were absent in both species. The aqueous and methanol extracts of Laurencia natalensis and Gelidium pristoides exhibited low inhibitory activities (less than 50%) against DPPH, ABTS, and nitric oxide radicals. Both species also showed low ferric reducing power. All the extracts were antiproliferative and cytotoxic against the HCC70 breast cancer cells, with L. natalensis exhibiting more significant inhibitory activity. However, its Solid Phase Extraction fractions did not display antiproliferative potential, unlike fraction 4 of G. pristoides. The study results suggest that both G. pristoides and L. natalensis possess bioactive compounds with potential anticancer activity. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021
Antiviral drug discovery: preparing for the next pandemic
- Adamson, Catherine S, Chibale, Kelly, Goss, Rebecca J M, Jaspars, Marcel, Newman, David J, Dorrington, Rosemary A
- Authors: Adamson, Catherine S , Chibale, Kelly , Goss, Rebecca J M , Jaspars, Marcel , Newman, David J , Dorrington, Rosemary A
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177499 , vital:42827 , DOI: 10.1039/d0cs01118e
- Description: Clinically approved antiviral drugs are currently available for only 10 of the more than 220 viruses known to infect humans. The SARS-CoV-2 outbreak has exposed the critical need for compounds that can be rapidly mobilised for the treatment of re-emerging or emerging viral diseases, while vaccine development is underway. We review the current status of antiviral therapies focusing on RNA viruses, highlighting strategies for antiviral drug discovery and discuss the challenges, solutions and options to accelerate drug discovery efforts.
- Full Text:
- Date Issued: 2021
- Authors: Adamson, Catherine S , Chibale, Kelly , Goss, Rebecca J M , Jaspars, Marcel , Newman, David J , Dorrington, Rosemary A
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/177499 , vital:42827 , DOI: 10.1039/d0cs01118e
- Description: Clinically approved antiviral drugs are currently available for only 10 of the more than 220 viruses known to infect humans. The SARS-CoV-2 outbreak has exposed the critical need for compounds that can be rapidly mobilised for the treatment of re-emerging or emerging viral diseases, while vaccine development is underway. We review the current status of antiviral therapies focusing on RNA viruses, highlighting strategies for antiviral drug discovery and discuss the challenges, solutions and options to accelerate drug discovery efforts.
- Full Text:
- Date Issued: 2021
Assisting Learners to Take Up Agency in Problem-Solving Activities
- Lambrechts, Therese, O’Donoghue, Rob B, Schudel, Ingrid J
- Authors: Lambrechts, Therese , O’Donoghue, Rob B , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435099 , vital:73130 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: The study was informed by an expansion of the ‘design research’ reported by McKenny and Reeves (2012) and it developed as a collaborative design process similar to that described by Voogt, Laferriere, Breuleux, Itow, Hickey and McKenny (2015). Voogt et al. approached design research as a successive and developing process of formative work by participants working together to design and assess a learning programme. In our case the design work was undertaken within a course-supported process of ESD design innovation among participating teachers and subject advisors.
- Full Text:
- Date Issued: 2021
- Authors: Lambrechts, Therese , O’Donoghue, Rob B , Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435099 , vital:73130 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: The study was informed by an expansion of the ‘design research’ reported by McKenny and Reeves (2012) and it developed as a collaborative design process similar to that described by Voogt, Laferriere, Breuleux, Itow, Hickey and McKenny (2015). Voogt et al. approached design research as a successive and developing process of formative work by participants working together to design and assess a learning programme. In our case the design work was undertaken within a course-supported process of ESD design innovation among participating teachers and subject advisors.
- Full Text:
- Date Issued: 2021