Acceptance of ambulatory blood pressure monitoring in a semi-rural population in South Africa:
- Chiwanza, Farisai, Irwin, Yoland, Dowse, Roslind
- Authors: Chiwanza, Farisai , Irwin, Yoland , Dowse, Roslind
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157072 , vital:40084 , DOI: https://doi.org/10.4102/hsag.v25i0.1336
- Description: Ambulatory blood pressure monitoring is a valuable tool that helps in providing an insight into the diagnosis and management of hypertension; however, no evidence exists of its acceptance in the diverse South African population. We assessed the acceptance of an ambulatory blood pressure monitor in patients attending public sector primary health care (PHC) clinics. Five PHC clinics in the Makana subdistrict in the Eastern Cape.
- Full Text:
- Authors: Chiwanza, Farisai , Irwin, Yoland , Dowse, Roslind
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157072 , vital:40084 , DOI: https://doi.org/10.4102/hsag.v25i0.1336
- Description: Ambulatory blood pressure monitoring is a valuable tool that helps in providing an insight into the diagnosis and management of hypertension; however, no evidence exists of its acceptance in the diverse South African population. We assessed the acceptance of an ambulatory blood pressure monitor in patients attending public sector primary health care (PHC) clinics. Five PHC clinics in the Makana subdistrict in the Eastern Cape.
- Full Text:
Acetophenone substituted phthalocyanines and their graphene quantum dots conjugates as photosensitizers for photodynamic antimicrobial chemotherapy against Staphylococcus aureus
- Openda, Yolande I, Sen, Pinar, Managa, Muthumuni, Nyokong, Tebello
- Authors: Openda, Yolande I , Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186507 , vital:44506 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.101607"
- Description: This work reports on the synthesis and characterization of novel acetophenone substituted phthalocyanines along with the self-assembled nanoconjugates formed via π-π stacking interaction between the synthesized unmetalated (2), zinc (3) and indium (4) phthalocyanines and graphene quantum dots (GQDs) to form 2@GQDs, 3@GQDs and 4@GQDs. The complexes and conjugates exhibited high singlet oxygen ranging from 0.20 to 0.79 in DMSO for Pcs and nanoconjugates where in all cases, the indium complexes showed the highest singlet oxygen quantum yields. The photodynamic antimicrobial chemotherapy activity of both phthalocyanines and nanoconjugates were tested against Staphylococcus aureus. 4@GQDs was found to be highly effective causing a 9.68 log reduction of the bacteria at 10 μM (based on Pc) when compared to 3.77 log reduction of 3@GQDs.
- Full Text:
- Authors: Openda, Yolande I , Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186507 , vital:44506 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.101607"
- Description: This work reports on the synthesis and characterization of novel acetophenone substituted phthalocyanines along with the self-assembled nanoconjugates formed via π-π stacking interaction between the synthesized unmetalated (2), zinc (3) and indium (4) phthalocyanines and graphene quantum dots (GQDs) to form 2@GQDs, 3@GQDs and 4@GQDs. The complexes and conjugates exhibited high singlet oxygen ranging from 0.20 to 0.79 in DMSO for Pcs and nanoconjugates where in all cases, the indium complexes showed the highest singlet oxygen quantum yields. The photodynamic antimicrobial chemotherapy activity of both phthalocyanines and nanoconjugates were tested against Staphylococcus aureus. 4@GQDs was found to be highly effective causing a 9.68 log reduction of the bacteria at 10 μM (based on Pc) when compared to 3.77 log reduction of 3@GQDs.
- Full Text:
Activity of diverse chalcones against several targets: statistical analysis of a high-throughput virtual screen of a custom chalcone library
- Authors: Sarron, Arthur F D
- Date: 2020
- Subjects: Acetophenone , Benzaldehyde , Ketones , Pyruvate kinase , Drug development , Aromatic compounds , Heat shock proteins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/116028 , vital:34291
- Description: Chalcone family molecules are well known to have therapeutic proprieties (anti-inflammatory, anti-microbial or anti-cancer, etc). However the mechanism of action in some cases is not well known. A virtual library of this family of compounds was constructed using custom scripts, based on the aldol condensation, and this library was modified further to analogues by expansion of the α,β-unsaturated ketone linker. Acetophenone and benzaldehyde derivatives which are available and purchasable were used as a base to design the chalcone virtual library. 8063 chalcones were constructed and geometrically optimized with Gaussian 09. Their physicochemical characteristics linked to the Lipinski rules were analyzed with Knime and CDK. The entire library was after docked against several targets including HIV-1 integrase, MRSA pyruvate kinase, HSP90, COX-1, COX-2, ALR2, MAOA, MAOB, acetylcholinesterase, butyrylcholinesterase and PLA2. With the exception of MAOA, which does not have a crystal structure ligand, all dockings were validated by redocking the original ligand provided by the literature. These targets are known in the literature to be inhibited by chalcone-derivatives. However, specificity of the particular known chalcone inhibitors to the particular targets is not known. To this end the performance of the generated chalcone library against the list of targets was of interest. The binding energy of ligand-protein complexes was generally good across the library. Statistical analysis including principal component analysis and hierarchical clustering analysis were made in order to investigate for any physical/chemical characteristics which might explain what chalcone features affect the binding energy of the ligand-protein complexes. The spherical polar coordinates defining the orientation of the binding poses were also calculated and used in the statistical analysis. The statistical analysis has allowed us to hypothesize the importance of these radial distances and the polar angles of key atoms in the chalcones in binding to the pyruvate kinase crystal structure. This was validated by the docking of another small library of compound models in which the α,β-unsaturated ketone chain of the chalcone was replaced by incrementally longer conjugated chains. Further studies on the chalcones themselves reveal rotameric systems in both cis and trans-configurations (which may impact binding), and also studied was the effect of Topliss-based modification and its impact of binding to HSP90. Molecular dynamics confirmed good binding of identified chalcone hits.
- Full Text:
- Authors: Sarron, Arthur F D
- Date: 2020
- Subjects: Acetophenone , Benzaldehyde , Ketones , Pyruvate kinase , Drug development , Aromatic compounds , Heat shock proteins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/116028 , vital:34291
- Description: Chalcone family molecules are well known to have therapeutic proprieties (anti-inflammatory, anti-microbial or anti-cancer, etc). However the mechanism of action in some cases is not well known. A virtual library of this family of compounds was constructed using custom scripts, based on the aldol condensation, and this library was modified further to analogues by expansion of the α,β-unsaturated ketone linker. Acetophenone and benzaldehyde derivatives which are available and purchasable were used as a base to design the chalcone virtual library. 8063 chalcones were constructed and geometrically optimized with Gaussian 09. Their physicochemical characteristics linked to the Lipinski rules were analyzed with Knime and CDK. The entire library was after docked against several targets including HIV-1 integrase, MRSA pyruvate kinase, HSP90, COX-1, COX-2, ALR2, MAOA, MAOB, acetylcholinesterase, butyrylcholinesterase and PLA2. With the exception of MAOA, which does not have a crystal structure ligand, all dockings were validated by redocking the original ligand provided by the literature. These targets are known in the literature to be inhibited by chalcone-derivatives. However, specificity of the particular known chalcone inhibitors to the particular targets is not known. To this end the performance of the generated chalcone library against the list of targets was of interest. The binding energy of ligand-protein complexes was generally good across the library. Statistical analysis including principal component analysis and hierarchical clustering analysis were made in order to investigate for any physical/chemical characteristics which might explain what chalcone features affect the binding energy of the ligand-protein complexes. The spherical polar coordinates defining the orientation of the binding poses were also calculated and used in the statistical analysis. The statistical analysis has allowed us to hypothesize the importance of these radial distances and the polar angles of key atoms in the chalcones in binding to the pyruvate kinase crystal structure. This was validated by the docking of another small library of compound models in which the α,β-unsaturated ketone chain of the chalcone was replaced by incrementally longer conjugated chains. Further studies on the chalcones themselves reveal rotameric systems in both cis and trans-configurations (which may impact binding), and also studied was the effect of Topliss-based modification and its impact of binding to HSP90. Molecular dynamics confirmed good binding of identified chalcone hits.
- Full Text:
African Foreign Policies: Selecting signifiers to explain agency
- Authors: Bischoff, Paul, 1954-
- Date: 2020
- Subjects: Africa Foreign relations 1960- , Africa Politics and government 1960-
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/161716 , vital:40657 , ISBN 9780367348281 , https://www.routledge.com/African-Foreign-Policies-Selecting-Signifiers-to-Explain-Agency/Bischoff/p/book/9780367348281
- Description: This book explores, at a time when several powers have become serious players on the continent, aspects of African agency, past and present, by African writers on foreign policy, representative of geography, language and state size. In the past, African foreign policy has largely been considered within the context of reactions to the international or global 'external factor'. This ground-breaking book, however, looks at how foreign policy has been crafted and used in response not just to external, but also, mainly, domestic imperatives or (theoretical) signifiers. As such, it narrates individual and changing foreign policy orientations over time - and as far back as independence - with mainly African-based scholars who present their own constructs of what is a useful theoretical narrative regarding foreign policy on the continent - how theory is adapted to local circumstance or substituted for continentally based ontologies. The book therefore contends that the African experience carries valuable import for expanding general understandings of foreign policy in general. This book will be of key interest to scholars and students of Foreign Policy Analysis, Foreign Policy Studies, African International Relations/Politics/Studies, Diplomacy and more broadly to International Relations. , Introduction / Paul-Henri Bischoff -- What Next? Past and present African foreign policy concepts and practices / Paul-Henri Bischoff -- The African Union as a Foreign Policy Player: African Agency in International Cooperation / Tshepo Gwatiwa -- Unprincipled Pragmatism and Anti-Imperialist Impulses in an Interconnected World: The Zuma Presidency, 2009-2017 / Mzukisi Qobo -- Towards A Strategic Culture Approach to Understanding and Conceptualising Ethiopia's Foreign Policy Towards Israel and the Middle Eastern Arab Countries / Makonnen Tesfaye -- Nigeria's Foreign Policy and Intervention Behaviour in Africa: What Role for Agency? / Olumuyiwa Amao -- Zimbabwe and New Signifiers: Towards a cultural political economy of Foreign Policy Making / Mike Mavura -- Realist Conceptions of Kenya's Foreign Policy and Foreign Policy Behaviour: A Theoretical and Contextual Disposition / Korwa Gombe Adar and Mercy Kathambi Kaburu -- Addressing the Conceptual Void of African Small State Foreign Policy in Orthodox Theory: A Case Study of Botswana's Principled Pragmatism / Kabelo M. Mahupela -- Tunisia's Foreign Policy Towards France Before and After an Undemanding 'Revolution': A Theoretical Explanation of the An-Nahdha-led Interim Governments' Soft Policy / Ahmed Ali Salem -- Straddling Between Convergence and Divergence: A Constructivist's View of Malawi's Foreign Policy in Post-independence Africa / Eugenio Njoloma -- Strategies of a Small State Between Realism and Liberalism: Sixty Years of Guinea's Diplomacy and Foreign Policy (1958-2018) / Issaka K. Souaré -- Rethinking SADC's Collective Policymaking Processes on External Relations and Non-state Participation for Region-building / Cecilia Lwiindi Nedziwe -- Towards an Understanding of the Interplay Between Ghana's Foreign and Defence Policies / Kwesi Aning and Kwaku Danso -- Conclusion / Paul-Henri Bischoff
- Full Text:
- Authors: Bischoff, Paul, 1954-
- Date: 2020
- Subjects: Africa Foreign relations 1960- , Africa Politics and government 1960-
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/161716 , vital:40657 , ISBN 9780367348281 , https://www.routledge.com/African-Foreign-Policies-Selecting-Signifiers-to-Explain-Agency/Bischoff/p/book/9780367348281
- Description: This book explores, at a time when several powers have become serious players on the continent, aspects of African agency, past and present, by African writers on foreign policy, representative of geography, language and state size. In the past, African foreign policy has largely been considered within the context of reactions to the international or global 'external factor'. This ground-breaking book, however, looks at how foreign policy has been crafted and used in response not just to external, but also, mainly, domestic imperatives or (theoretical) signifiers. As such, it narrates individual and changing foreign policy orientations over time - and as far back as independence - with mainly African-based scholars who present their own constructs of what is a useful theoretical narrative regarding foreign policy on the continent - how theory is adapted to local circumstance or substituted for continentally based ontologies. The book therefore contends that the African experience carries valuable import for expanding general understandings of foreign policy in general. This book will be of key interest to scholars and students of Foreign Policy Analysis, Foreign Policy Studies, African International Relations/Politics/Studies, Diplomacy and more broadly to International Relations. , Introduction / Paul-Henri Bischoff -- What Next? Past and present African foreign policy concepts and practices / Paul-Henri Bischoff -- The African Union as a Foreign Policy Player: African Agency in International Cooperation / Tshepo Gwatiwa -- Unprincipled Pragmatism and Anti-Imperialist Impulses in an Interconnected World: The Zuma Presidency, 2009-2017 / Mzukisi Qobo -- Towards A Strategic Culture Approach to Understanding and Conceptualising Ethiopia's Foreign Policy Towards Israel and the Middle Eastern Arab Countries / Makonnen Tesfaye -- Nigeria's Foreign Policy and Intervention Behaviour in Africa: What Role for Agency? / Olumuyiwa Amao -- Zimbabwe and New Signifiers: Towards a cultural political economy of Foreign Policy Making / Mike Mavura -- Realist Conceptions of Kenya's Foreign Policy and Foreign Policy Behaviour: A Theoretical and Contextual Disposition / Korwa Gombe Adar and Mercy Kathambi Kaburu -- Addressing the Conceptual Void of African Small State Foreign Policy in Orthodox Theory: A Case Study of Botswana's Principled Pragmatism / Kabelo M. Mahupela -- Tunisia's Foreign Policy Towards France Before and After an Undemanding 'Revolution': A Theoretical Explanation of the An-Nahdha-led Interim Governments' Soft Policy / Ahmed Ali Salem -- Straddling Between Convergence and Divergence: A Constructivist's View of Malawi's Foreign Policy in Post-independence Africa / Eugenio Njoloma -- Strategies of a Small State Between Realism and Liberalism: Sixty Years of Guinea's Diplomacy and Foreign Policy (1958-2018) / Issaka K. Souaré -- Rethinking SADC's Collective Policymaking Processes on External Relations and Non-state Participation for Region-building / Cecilia Lwiindi Nedziwe -- Towards an Understanding of the Interplay Between Ghana's Foreign and Defence Policies / Kwesi Aning and Kwaku Danso -- Conclusion / Paul-Henri Bischoff
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Afromelampsalta, a new genus, a new species, and five new combinations of African cicadettine cicadas (Hemiptera: Cicadidae: Cicadettinae):
- Sanborn, Allen F, Villet, Martin H
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140680 , vital:37909
- Description: Afromelampsalta n. gen. is described for African species currently assigned to the genera Melampsalta Kolenati, 1857. Cicadetta Kolenati, 1857 and Pauropsalta Goding and Froggatt, 1904, and the new species Afromelampsalta luteofasciata n. gen., n. sp. is described. Afromelampsalta aethiopica (Distant, 1905) n. comb., A. cadisia (Walker, 1850) n. comb. and A. leucoptera (Germar, 1830) n. comb. are reassigned from Melampsalta to Afromelampsalta n. gen., A. limitata (Walker, 1852) n. comb. is transferred from Cicadetta Kolenati, 1857 and A. mimica (Distant ,1907) n. comb. is transferred from Pauropsalta Goding and Froggatt, 1904 to Afromelampsalta n. gen. Notes on the biology of the new species, a description of the exuvia of A. mimica n. comb., and a key to the species of African Cicadettini are provided.
- Full Text:
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140680 , vital:37909
- Description: Afromelampsalta n. gen. is described for African species currently assigned to the genera Melampsalta Kolenati, 1857. Cicadetta Kolenati, 1857 and Pauropsalta Goding and Froggatt, 1904, and the new species Afromelampsalta luteofasciata n. gen., n. sp. is described. Afromelampsalta aethiopica (Distant, 1905) n. comb., A. cadisia (Walker, 1850) n. comb. and A. leucoptera (Germar, 1830) n. comb. are reassigned from Melampsalta to Afromelampsalta n. gen., A. limitata (Walker, 1852) n. comb. is transferred from Cicadetta Kolenati, 1857 and A. mimica (Distant ,1907) n. comb. is transferred from Pauropsalta Goding and Froggatt, 1904 to Afromelampsalta n. gen. Notes on the biology of the new species, a description of the exuvia of A. mimica n. comb., and a key to the species of African Cicadettini are provided.
- Full Text:
Agents sans frontiers: cross-border aquatic weed biological control in the rivers of southern Mozambique
- Langa, Sílvia da Fátima, Hill, Martin P, Compton, Stephen G
- Authors: Langa, Sílvia da Fátima , Hill, Martin P , Compton, Stephen G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148998 , vital:38794 , DOI: 10.2989/16085914.2020.1749551
- Description: Biological control is an effective ways of controlling aquatic plants, especially in South Africa. Release of biological control agents has been limited to Mozambique, where water hyacinth (Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae)), water lettuce (Pistia stratiotes L. (Araceae)), red water ferns (Azolla spp. (Azollaceae)) and salvinia (Salvinia molesta DS Mitch. (Salviniaceae)) are significant weeds in the south of the country. In 2009, we assessed the status of these weeds in seven rivers across southern Mozambique and recorded whether any biocontrol agents were present.
- Full Text:
- Authors: Langa, Sílvia da Fátima , Hill, Martin P , Compton, Stephen G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148998 , vital:38794 , DOI: 10.2989/16085914.2020.1749551
- Description: Biological control is an effective ways of controlling aquatic plants, especially in South Africa. Release of biological control agents has been limited to Mozambique, where water hyacinth (Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae)), water lettuce (Pistia stratiotes L. (Araceae)), red water ferns (Azolla spp. (Azollaceae)) and salvinia (Salvinia molesta DS Mitch. (Salviniaceae)) are significant weeds in the south of the country. In 2009, we assessed the status of these weeds in seven rivers across southern Mozambique and recorded whether any biocontrol agents were present.
- Full Text:
Alignment in the orientation of LOFAR radio sources:
- Osinga, E, Miley, G K, van Weeren, R J, Shimwell, T W, Duncan, K J, Hardcastle, M J, Mechev, A P, Röttgering, H J A, Tasse, C, Williams, W L
- Authors: Osinga, E , Miley, G K , van Weeren, R J , Shimwell, T W , Duncan, K J , Hardcastle, M J , Mechev, A P , Röttgering, H J A , Tasse, C , Williams, W L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163452 , vital:41039 , https://doi.org/10.1051/0004-6361/202037680
- Description: Various studies have laid claim to finding an alignment of the polarization vectors or radio jets of active galactic nuclei over large distances, but these results have proven controversial and so far, there is no clear explanation for this observed alignment. To investigate this case further, we tested the hypothesis that the position angles of radio galaxies are randomly oriented in the sky by using data from the Low-Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS). A sample of 7555 double-lobed radio galaxies was extracted from the list of 318 520 radio sources in the first data release of LoTSS at 150 MHz. We performed statistical tests for uniformity of the two-dimensional (2D) orientations for the complete 7555 source sample. We also tested the orientation uniformity in three dimensions (3D) for the 4212 source sub-sample with photometric or spectroscopic redshifts.
- Full Text:
- Authors: Osinga, E , Miley, G K , van Weeren, R J , Shimwell, T W , Duncan, K J , Hardcastle, M J , Mechev, A P , Röttgering, H J A , Tasse, C , Williams, W L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163452 , vital:41039 , https://doi.org/10.1051/0004-6361/202037680
- Description: Various studies have laid claim to finding an alignment of the polarization vectors or radio jets of active galactic nuclei over large distances, but these results have proven controversial and so far, there is no clear explanation for this observed alignment. To investigate this case further, we tested the hypothesis that the position angles of radio galaxies are randomly oriented in the sky by using data from the Low-Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS). A sample of 7555 double-lobed radio galaxies was extracted from the list of 318 520 radio sources in the first data release of LoTSS at 150 MHz. We performed statistical tests for uniformity of the two-dimensional (2D) orientations for the complete 7555 source sample. We also tested the orientation uniformity in three dimensions (3D) for the 4212 source sub-sample with photometric or spectroscopic redshifts.
- Full Text:
AMBER force field parameters for the Zn (II) ions of the tunneling-fold enzymes GTP cyclohydrolase I and 6-pyruvoyl tetrahydropterin synthase
- Khairallah, Afrah, Tastan Bishop, Ozlem, Moses, Vuyani
- Authors: Khairallah, Afrah , Tastan Bishop, Ozlem , Moses, Vuyani
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429360 , vital:72604 , xlink:href="https://doi.org/10.1080/07391102.2020.1796800"
- Description: The folate biosynthesis pathway is an essential pathway for cell growth and survival. Folate derivatives serve as a source of the one-carbon units in several intracellular metabolic reactions. Rapidly dividing cells rely heavily on the availability of folate derivatives for their proliferation. As a result, drugs targeting this pathway have shown to be effective against tumor cells and pathogens, but drug resistance against the available antifolate drugs emerged quickly. Therefore, there is a need to develop new treatment strategies and identify alternative metabolic targets. The two de novo folate biosynthesis pathway enzymes, GTP cyclohydrolase I (GCH1) and 6-pyruvoyl tetrahydropterin synthase (PTPS), can provide an alternative strategy to overcome the drug resistance that emerged in the two primary targeted enzymes dihydrofolate reductase and dihydropteroate synthase. Both GCH1 and PTPS enzymes contain Zn2+ ions in their active sites, and to accurately study their dynamic behaviors using all-atom molecular dynamics (MD) simulations, appropriate parameters that can describe their metal sites should be developed and validated. In this study, force field parameters of the GCH1 and PTPS metal centers were generated using quantum mechanics (QM) calculations and then validated through MD simulations to ensure their accuracy in describing and maintaining the Zn2+ ion coordination environment. The derived force field parameters will provide accurate and reliable MD simulations involving these two enzymes for future in-silico identification of drug candidates against the GCH1 and PTPS enzymes.
- Full Text:
- Authors: Khairallah, Afrah , Tastan Bishop, Ozlem , Moses, Vuyani
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429360 , vital:72604 , xlink:href="https://doi.org/10.1080/07391102.2020.1796800"
- Description: The folate biosynthesis pathway is an essential pathway for cell growth and survival. Folate derivatives serve as a source of the one-carbon units in several intracellular metabolic reactions. Rapidly dividing cells rely heavily on the availability of folate derivatives for their proliferation. As a result, drugs targeting this pathway have shown to be effective against tumor cells and pathogens, but drug resistance against the available antifolate drugs emerged quickly. Therefore, there is a need to develop new treatment strategies and identify alternative metabolic targets. The two de novo folate biosynthesis pathway enzymes, GTP cyclohydrolase I (GCH1) and 6-pyruvoyl tetrahydropterin synthase (PTPS), can provide an alternative strategy to overcome the drug resistance that emerged in the two primary targeted enzymes dihydrofolate reductase and dihydropteroate synthase. Both GCH1 and PTPS enzymes contain Zn2+ ions in their active sites, and to accurately study their dynamic behaviors using all-atom molecular dynamics (MD) simulations, appropriate parameters that can describe their metal sites should be developed and validated. In this study, force field parameters of the GCH1 and PTPS metal centers were generated using quantum mechanics (QM) calculations and then validated through MD simulations to ensure their accuracy in describing and maintaining the Zn2+ ion coordination environment. The derived force field parameters will provide accurate and reliable MD simulations involving these two enzymes for future in-silico identification of drug candidates against the GCH1 and PTPS enzymes.
- Full Text:
AMBER force field parameters for the Zn (II) ions of the tunneling-fold enzymes GTP cyclohydrolase I and 6-pyruvoyl tetrahydropterin synthase:
- Khairallah, Afrah, Tastan Bishop, Özlem, Moses, Vuyani
- Authors: Khairallah, Afrah , Tastan Bishop, Özlem , Moses, Vuyani
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163068 , vital:41009 , DOI: 10.1080/07391102.2020.1796800
- Description: The folate biosynthesis pathway is an essential pathway for cell growth and survival. Folate derivatives serve as a source of the one-carbon units in several intracellular metabolic reactions. Rapidly dividing cells rely heavily on the availability of folate derivatives for their proliferation. As a result, drugs targeting this pathway have shown to be effective against tumor cells and pathogens, but drug resistance against the available antifolate drugs emerged quickly. Therefore, there is a need to develop new treatment strategies and identify alternative metabolic targets. The two de novo folate biosynthesis pathway enzymes, GTP cyclohydrolase I (GCH1) and 6-pyruvoyl tetrahydropterin synthase (PTPS), can provide an alternative strategy to overcome the drug resistance that emerged in the two primary targeted enzymes dihydrofolate reductase and dihydropteroate synthase.
- Full Text:
- Authors: Khairallah, Afrah , Tastan Bishop, Özlem , Moses, Vuyani
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163068 , vital:41009 , DOI: 10.1080/07391102.2020.1796800
- Description: The folate biosynthesis pathway is an essential pathway for cell growth and survival. Folate derivatives serve as a source of the one-carbon units in several intracellular metabolic reactions. Rapidly dividing cells rely heavily on the availability of folate derivatives for their proliferation. As a result, drugs targeting this pathway have shown to be effective against tumor cells and pathogens, but drug resistance against the available antifolate drugs emerged quickly. Therefore, there is a need to develop new treatment strategies and identify alternative metabolic targets. The two de novo folate biosynthesis pathway enzymes, GTP cyclohydrolase I (GCH1) and 6-pyruvoyl tetrahydropterin synthase (PTPS), can provide an alternative strategy to overcome the drug resistance that emerged in the two primary targeted enzymes dihydrofolate reductase and dihydropteroate synthase.
- Full Text:
An analysis of carbon tax and other environmental levies: a South African and international perspective
- Authors: Vuzane, Rolihlahla
- Date: 2020
- Subjects: Carbon taxes , Carbon taxes -- South Africa , Environmental impact charges , Environmental impact charges -- South Africa , Taxation -- Environmental aspects , Taxation -- Environmental aspects -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/167676 , vital:41502
- Description: As a “Non-Annex 1” country, there was no obligation for South Africa to reduce its carbon emissions. South Africa undertook, of its own volition, to take measures to reduce 34% of the carbon monoxide emissions by 2020 and 42% by 2025 respectively. In response, South Africa promulgated the Carbon Tax Act, No. 15 of 2019. This study seeks to answer the question: After analysing the range of environmental taxes levied in the Scandinavian countries (Denmark, Finland, Norway and Sweden) and in South Africa, are there lessons that can be learnt for South Africa? In answering this question, the carbon tax structure in South Africa and in selected Scandinavian countries is analysed, together with existing environmental taxes and the related policies, using a literature study. What is evident from the Scandinavian countries studied, is that environmental taxes have distributional effects and are effective in reducing carbon emissions. The major result of the study was that the real weakness of the newly introduced Carbon Tax Act is that in both in the first and second phase of its implementation, the carbon tax rate is too low to send an appropriate signal to the market and would not have the desired outcome. In addition, there are currently no guidelines that inform the revenue recycling technique to ensure transparency of revenue usage, improved energy management, or how the Carbon Tax Act will promote environmental quality. A major concern is that carbon tax revenue will not be ring-fenced. Given that South Africa is a developing country and depends mainly on non-renewable energy, it is inevitable that most of its sectors will be subject to the carbon tax. A plausible approach is the one that promotes the idea of taxing those more heavily that contribute most to environmental degradation and are highly energy concentrated, to promote parity between the harm to the environment and the taxes levied to redress the harm.
- Full Text:
- Authors: Vuzane, Rolihlahla
- Date: 2020
- Subjects: Carbon taxes , Carbon taxes -- South Africa , Environmental impact charges , Environmental impact charges -- South Africa , Taxation -- Environmental aspects , Taxation -- Environmental aspects -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/167676 , vital:41502
- Description: As a “Non-Annex 1” country, there was no obligation for South Africa to reduce its carbon emissions. South Africa undertook, of its own volition, to take measures to reduce 34% of the carbon monoxide emissions by 2020 and 42% by 2025 respectively. In response, South Africa promulgated the Carbon Tax Act, No. 15 of 2019. This study seeks to answer the question: After analysing the range of environmental taxes levied in the Scandinavian countries (Denmark, Finland, Norway and Sweden) and in South Africa, are there lessons that can be learnt for South Africa? In answering this question, the carbon tax structure in South Africa and in selected Scandinavian countries is analysed, together with existing environmental taxes and the related policies, using a literature study. What is evident from the Scandinavian countries studied, is that environmental taxes have distributional effects and are effective in reducing carbon emissions. The major result of the study was that the real weakness of the newly introduced Carbon Tax Act is that in both in the first and second phase of its implementation, the carbon tax rate is too low to send an appropriate signal to the market and would not have the desired outcome. In addition, there are currently no guidelines that inform the revenue recycling technique to ensure transparency of revenue usage, improved energy management, or how the Carbon Tax Act will promote environmental quality. A major concern is that carbon tax revenue will not be ring-fenced. Given that South Africa is a developing country and depends mainly on non-renewable energy, it is inevitable that most of its sectors will be subject to the carbon tax. A plausible approach is the one that promotes the idea of taxing those more heavily that contribute most to environmental degradation and are highly energy concentrated, to promote parity between the harm to the environment and the taxes levied to redress the harm.
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An analysis of how visualisation capabilities in dynamic geometric software develop meaning-making of mathematical concepts in selected Grade 11 learners
- Authors: Mavani, Deepack Pravin
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa , Mathematics -- Computer programs , Mathematics -- Study and teaching (Secondary) -- South Africa -- Case studies , Mathematics -- Study and teaching -- Activity programs , Educational technology , Visualization
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143213 , vital:38211
- Description: Visualisation plays a central role in developing mathematical ideas because it can be used to make these ideas explicit and visible, and thus has the potential to advance understanding. This study centred around the GeoGebra Literacy Initiative Project (GLIP), a teacher development initiative in Mthatha that aimed to grow and develop appropriate Information and Communication Technology (ICT) skills in teachers, to harness the teaching and learning potential of GeoGebra. GeoGebra is a dynamic geometric software package that is very interactive and makes use of powerful features to create images which can be moved around the computer screen for mathematical exploration. This research project was located within GLIP and analysed how GeoGebra applets develop conceptual and procedural understanding in selected Grade 11 learners. One aspect of GLIP was for teachers to use GeoGebra applets that they had developed themselves and implemented in their classrooms in pre-determined cycles that were aligned to the curriculum. My study specifically focused on how the selected learners made use of these applets and explored how learning had taken place in terms of developing mathematical meaning-making. This interpretive research study was designed as a case study. The case was a cohort of selected Grade 11 learners who had been taught by GLIP teachers, and my unit of analysis was the learners’ interaction with the applets. A screen capturing software package was used to capture learners’ interactions with the GeoGebra. My data consisted mainly of recorded observations and interviews. An analytical framework derived from the works of Kilpatrick, Swafford, and Findell (2001) and Carter et al. (2009) guided and informed the data analysis of the learners’ activities with the GeoGebra. The theoretical orientation of this study was constructivist learning. An in-depth analysis and detailed descriptions of the participants’ interactions enabled me to gain a comprehensive understanding of their meaning-making processes in a technological classroom context. An analysis across the participants identified distinguishable patterns or differences in the development of the learners’ mathematical proficiency and making sense of mathematical ideas. The research argued that technology enabled visualisation was a powerful tool to not only enrich mathematically activities, but to also enrich conceptual and procedural understanding. The findings recognised that exploration of, or manipulation on mathematical objects in GeoGebra was a key activity in the participants’ meaning-making process. It also enabled learners to offer self-proclaimed theories
- Full Text:
- Authors: Mavani, Deepack Pravin
- Date: 2020
- Subjects: Mathematics -- Study and teaching (Secondary) -- South Africa , Mathematics -- Computer programs , Mathematics -- Study and teaching (Secondary) -- South Africa -- Case studies , Mathematics -- Study and teaching -- Activity programs , Educational technology , Visualization
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/143213 , vital:38211
- Description: Visualisation plays a central role in developing mathematical ideas because it can be used to make these ideas explicit and visible, and thus has the potential to advance understanding. This study centred around the GeoGebra Literacy Initiative Project (GLIP), a teacher development initiative in Mthatha that aimed to grow and develop appropriate Information and Communication Technology (ICT) skills in teachers, to harness the teaching and learning potential of GeoGebra. GeoGebra is a dynamic geometric software package that is very interactive and makes use of powerful features to create images which can be moved around the computer screen for mathematical exploration. This research project was located within GLIP and analysed how GeoGebra applets develop conceptual and procedural understanding in selected Grade 11 learners. One aspect of GLIP was for teachers to use GeoGebra applets that they had developed themselves and implemented in their classrooms in pre-determined cycles that were aligned to the curriculum. My study specifically focused on how the selected learners made use of these applets and explored how learning had taken place in terms of developing mathematical meaning-making. This interpretive research study was designed as a case study. The case was a cohort of selected Grade 11 learners who had been taught by GLIP teachers, and my unit of analysis was the learners’ interaction with the applets. A screen capturing software package was used to capture learners’ interactions with the GeoGebra. My data consisted mainly of recorded observations and interviews. An analytical framework derived from the works of Kilpatrick, Swafford, and Findell (2001) and Carter et al. (2009) guided and informed the data analysis of the learners’ activities with the GeoGebra. The theoretical orientation of this study was constructivist learning. An in-depth analysis and detailed descriptions of the participants’ interactions enabled me to gain a comprehensive understanding of their meaning-making processes in a technological classroom context. An analysis across the participants identified distinguishable patterns or differences in the development of the learners’ mathematical proficiency and making sense of mathematical ideas. The research argued that technology enabled visualisation was a powerful tool to not only enrich mathematically activities, but to also enrich conceptual and procedural understanding. The findings recognised that exploration of, or manipulation on mathematical objects in GeoGebra was a key activity in the participants’ meaning-making process. It also enabled learners to offer self-proclaimed theories
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An analysis of indicators disclosed in the integrated annual reports of selected South African retailers
- Authors: Blignaut, Anna Cornelia
- Date: 2020
- Subjects: Financial statements -- South Africa -- Case studies , Retail trade -- South Africa
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/140859 , vital:37924
- Description: This study aimed to analyse the indicators disclosed in the Integrated Annual Reports (IARs) of selected South African retailers. This was firstly done by identifying the six capital and governance indicators retailers report on in order to analyse the commonalities and differences between them, secondly by identifying and assessing evidence of integrated thinking and lastly by making recommendations for optimal retail sector reporting. IARs from Pick n Pay Stores Ltd, Shoprite Holdings Ltd, Spar Group Ltd and Woolworths Holdings Ltd were analysed using content analysis. The results found noteworthy differences in IAR composition in terms of report length and the sections retailers devoted more or less of their report to. Governance and Remuneration indicator disclosure did not allow for broad comparison among all four retailers. In terms of indicator disclosure few indicators were disclosed by all retailers, whilst many were only disclosed by one retailer. Disclosures related to all six capitals were found, yet some indicators were disclosed excessively. Paradoxically, insufficient disclosure of indicators that are easily measurable and low levels of negative or unfavourable indicator disclosure was also apparent in this study. The comparability of indicators was influenced by the aggregation and disaggregation of indicators as well as the lack of consistency in the terminology used in IARs. Indicator disclosure also revealed several trends in the South African retail industry. This research identified the following six themes related to integrated thinking in the sample IARs. Retailers understand the connection between capitals, express consideration for multiple stakeholders and appreciate the context in which they operate, to some extent. Retailers were also found to have different interpretations of sustainability as part of their strategy and risk management whilst the completeness and consistency of information disclosed and retailers’ conceptualisation of value-added in IAR has not yet developed to the same extent across the retail industry. This study finally makes recommendations that may be used for optimal retail sector reporting with regards to the integrated reporting process as well as the integrated report itself. Addressing the former it is recommended that: integrated reporting be viewed as a means to build an internal understanding of their sustainability practices; integrated thinking be included as part of their strategic planning process; all capitals be considered in decision making; communication be established with others in the retail industry and that retailers engage with the IIRC on integrated reporting issues. In terms of the IAR itself, it is recommended that retailers ensure consistency in the terminology used and that the disaggregation of indicators is done in a consistent way. Retailers should include a balance of positive and negative disclosures as well as context-based indicators and seek assurance of the social, environmental and ethical information in their IARs. Finally, retailers need to set measurable sustainability performance targets and link them to specific performance indicators. The results of this study are not without limitations. The identification and categorisation of an indicator was largely based on the researcher’s own judgement in the content analysis process and can be highlighted as the main limitation of this research.
- Full Text:
- Authors: Blignaut, Anna Cornelia
- Date: 2020
- Subjects: Financial statements -- South Africa -- Case studies , Retail trade -- South Africa
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/140859 , vital:37924
- Description: This study aimed to analyse the indicators disclosed in the Integrated Annual Reports (IARs) of selected South African retailers. This was firstly done by identifying the six capital and governance indicators retailers report on in order to analyse the commonalities and differences between them, secondly by identifying and assessing evidence of integrated thinking and lastly by making recommendations for optimal retail sector reporting. IARs from Pick n Pay Stores Ltd, Shoprite Holdings Ltd, Spar Group Ltd and Woolworths Holdings Ltd were analysed using content analysis. The results found noteworthy differences in IAR composition in terms of report length and the sections retailers devoted more or less of their report to. Governance and Remuneration indicator disclosure did not allow for broad comparison among all four retailers. In terms of indicator disclosure few indicators were disclosed by all retailers, whilst many were only disclosed by one retailer. Disclosures related to all six capitals were found, yet some indicators were disclosed excessively. Paradoxically, insufficient disclosure of indicators that are easily measurable and low levels of negative or unfavourable indicator disclosure was also apparent in this study. The comparability of indicators was influenced by the aggregation and disaggregation of indicators as well as the lack of consistency in the terminology used in IARs. Indicator disclosure also revealed several trends in the South African retail industry. This research identified the following six themes related to integrated thinking in the sample IARs. Retailers understand the connection between capitals, express consideration for multiple stakeholders and appreciate the context in which they operate, to some extent. Retailers were also found to have different interpretations of sustainability as part of their strategy and risk management whilst the completeness and consistency of information disclosed and retailers’ conceptualisation of value-added in IAR has not yet developed to the same extent across the retail industry. This study finally makes recommendations that may be used for optimal retail sector reporting with regards to the integrated reporting process as well as the integrated report itself. Addressing the former it is recommended that: integrated reporting be viewed as a means to build an internal understanding of their sustainability practices; integrated thinking be included as part of their strategic planning process; all capitals be considered in decision making; communication be established with others in the retail industry and that retailers engage with the IIRC on integrated reporting issues. In terms of the IAR itself, it is recommended that retailers ensure consistency in the terminology used and that the disaggregation of indicators is done in a consistent way. Retailers should include a balance of positive and negative disclosures as well as context-based indicators and seek assurance of the social, environmental and ethical information in their IARs. Finally, retailers need to set measurable sustainability performance targets and link them to specific performance indicators. The results of this study are not without limitations. The identification and categorisation of an indicator was largely based on the researcher’s own judgement in the content analysis process and can be highlighted as the main limitation of this research.
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An Analysis of Internet Background Radiation within an African IPv4 netblock
- Authors: Hendricks, Wadeegh
- Date: 2020
- Subjects: Computer networks -- Monitoring –- South Africa , Dark Web , Computer networks -- Security measures –- South Africa , Universities and Colleges -- Computer networks -- Security measures , Malware (Computer software) , TCP/IP (Computer network protocol)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103791 , vital:32298
- Description: The use of passive network sensors has in the past proven to be quite effective in monitoring and analysing the current state of traffic on a network. Internet traffic destined to a routable, yet unused address block is often referred to as Internet Background Radiation (IBR) and characterised as unsolicited. This unsolicited traffic is however quite valuable to researchers in that it allows them to study the traffic patterns in a covert manner. IBR is largely composed of network and port scanning traffic, backscatter packets from virus and malware activity and to a lesser extent, misconfiguration of network devices. This research answers the following two questions: (1) What is the current state of IBR within the context of a South African IP address space and (2) Can any anomalies be detected in the traffic, with specific reference to current global malware attacks such as Mirai and similar. Rhodes University operates five IPv4 passive network sensors, commonly known as network telescopes, each monitoring its own /24 IP address block. The oldest of these network telescopes has been collecting traffic for over a decade, with the newest being established in 2011. This research focuses on the in-depth analysis of the traffic captured by one telescope in the 155/8 range over a 12 month period, from January to December 2017. The traffic was analysed and classified according the protocol, TCP flag, source IP address, destination port, packet count and payload size. Apart from the normal network traffic graphs and tables, a geographic heatmap of source traffic was also created, based on the source IP address. Spikes and noticeable variances in traffic patterns were further investigated and evidence of Mirai like malware activity was observed. Network and port scanning were found to comprise the largest amount of traffic, accounting for over 90% of the total IBR. Various scanning techniques were identified, including low level passive scanning and much higher level active scanning.
- Full Text:
- Authors: Hendricks, Wadeegh
- Date: 2020
- Subjects: Computer networks -- Monitoring –- South Africa , Dark Web , Computer networks -- Security measures –- South Africa , Universities and Colleges -- Computer networks -- Security measures , Malware (Computer software) , TCP/IP (Computer network protocol)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/103791 , vital:32298
- Description: The use of passive network sensors has in the past proven to be quite effective in monitoring and analysing the current state of traffic on a network. Internet traffic destined to a routable, yet unused address block is often referred to as Internet Background Radiation (IBR) and characterised as unsolicited. This unsolicited traffic is however quite valuable to researchers in that it allows them to study the traffic patterns in a covert manner. IBR is largely composed of network and port scanning traffic, backscatter packets from virus and malware activity and to a lesser extent, misconfiguration of network devices. This research answers the following two questions: (1) What is the current state of IBR within the context of a South African IP address space and (2) Can any anomalies be detected in the traffic, with specific reference to current global malware attacks such as Mirai and similar. Rhodes University operates five IPv4 passive network sensors, commonly known as network telescopes, each monitoring its own /24 IP address block. The oldest of these network telescopes has been collecting traffic for over a decade, with the newest being established in 2011. This research focuses on the in-depth analysis of the traffic captured by one telescope in the 155/8 range over a 12 month period, from January to December 2017. The traffic was analysed and classified according the protocol, TCP flag, source IP address, destination port, packet count and payload size. Apart from the normal network traffic graphs and tables, a geographic heatmap of source traffic was also created, based on the source IP address. Spikes and noticeable variances in traffic patterns were further investigated and evidence of Mirai like malware activity was observed. Network and port scanning were found to comprise the largest amount of traffic, accounting for over 90% of the total IBR. Various scanning techniques were identified, including low level passive scanning and much higher level active scanning.
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An Analysis of Self-Help Agricultural Projects in Rothe Village, Lesotho
- Authors: Phiri, Bokang
- Date: 2020
- Subjects: Community development -- Lesotho , Rural development -- Lesotho , Rural development projects - Lesotho -- Case studies , Agricultural development projects - Lesotho -- Case studies , Agricultural development projects - Lesotho -- Evaluation , Rural Self-Help Development Association
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144242 , vital:38324
- Description: The study analysed self-help agricultural projects in Rothe, Lesotho to ascertain whether they improve the quality lives of Rothe villagers. As much as government driven self-help projects in Lesotho contribute to growing the rural economy, there is limited research that looks the sustainability of these interventions. Much of the literature in Lesotho reveal that self-help agricultural projects have focused on people being provided with food-for-work, or cash-for-work, these offered little benefits and temporary relief for hunger for beneficiaries. This study seeks to understand how self-help agricultural projects can sustainable improve the lives of Rothe community in Lesotho. The study drew from Sustainable Livelihoods Approach to understand self-help agricultural projects in Rothe, Lesotho. The study employed a qualitative case study approach, supplemented by purposive and snowball sampling methods and semi-structured interviews to select and interview self-help project beneficiaries and Field Officers of RSDA in Rothe Village. The findings revealed that self-help agricultural projects are alternative development interventions for improving the quality lives of poor rural villagers. These development interventions enable people to access livelihoods resources, assets, and social capitals that are important to improve, and sustain livelihoods. Additionally, they improve capabilities of the poor, and contribute to their overall development. The thesis concludes that these development interventions have a role to play in alleviating rural poverty lives as a way to ensure equitable distribution of resources. The study recommends that the government, people on the ground and RSDA should work together to strengthen people’s capabilities through self-help agricultural projects to promote welfare and well-being of rural people.
- Full Text:
- Authors: Phiri, Bokang
- Date: 2020
- Subjects: Community development -- Lesotho , Rural development -- Lesotho , Rural development projects - Lesotho -- Case studies , Agricultural development projects - Lesotho -- Case studies , Agricultural development projects - Lesotho -- Evaluation , Rural Self-Help Development Association
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144242 , vital:38324
- Description: The study analysed self-help agricultural projects in Rothe, Lesotho to ascertain whether they improve the quality lives of Rothe villagers. As much as government driven self-help projects in Lesotho contribute to growing the rural economy, there is limited research that looks the sustainability of these interventions. Much of the literature in Lesotho reveal that self-help agricultural projects have focused on people being provided with food-for-work, or cash-for-work, these offered little benefits and temporary relief for hunger for beneficiaries. This study seeks to understand how self-help agricultural projects can sustainable improve the lives of Rothe community in Lesotho. The study drew from Sustainable Livelihoods Approach to understand self-help agricultural projects in Rothe, Lesotho. The study employed a qualitative case study approach, supplemented by purposive and snowball sampling methods and semi-structured interviews to select and interview self-help project beneficiaries and Field Officers of RSDA in Rothe Village. The findings revealed that self-help agricultural projects are alternative development interventions for improving the quality lives of poor rural villagers. These development interventions enable people to access livelihoods resources, assets, and social capitals that are important to improve, and sustain livelihoods. Additionally, they improve capabilities of the poor, and contribute to their overall development. The thesis concludes that these development interventions have a role to play in alleviating rural poverty lives as a way to ensure equitable distribution of resources. The study recommends that the government, people on the ground and RSDA should work together to strengthen people’s capabilities through self-help agricultural projects to promote welfare and well-being of rural people.
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An analysis of South Africa’s food security policy frameworks from a food sovereignty perspective: challenges and implications for genuine long-term food security
- Authors: Hoepfl, Jason
- Date: 2020
- Subjects: Food sovereignty -- South Africa , Food security -- South Africa , Food security -- Government policy -- South Africa , Food security -- Climatic factors -- South Africa , Food policy -- Government policy -- South Africa , Agriculture and state -- South Africa , Food industry and trade -- Government policy -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/162851 , vital:40990
- Description: Food price volatility, ecological shocks and unprecedented levels of hunger and obesity are increasing concerns within food security governance, as is the emergence of food sovereignty in broadening critical discussions around food, water, energy and environmental crises. This thesis analyses this changing terrain in the context of South African policy. It analyses shifts in policymaking and the capability of South Africa’s food security policy frameworks to include food sovereignty principles and in so doing support genuine long-term food security. A shift in policy priorities from household production, trade and income opportunities towards social safety nets and nutritional interventions is identified. This focus is constrained by an inability to affect structural changes within a deeply inequitable food landscape. An emphasis on commercial farming and unwillingness to challenge large agribusiness, value chains and corporate retail has enabled social differentiation in access to food and the country’s colonial land dispensation to continue. Consequently, markets have continued to be antipathetic to the needs of poor producers and consumers in South Africa. To overcome these structural constraints, food security policy needs to be framed within a more radical normative agenda. This is important for challenging inequitable power relations and asserting the social and ecological imperatives of healthy food systems. Food sovereignty has significant potential to support a normative agenda by supporting the multiple farming practices, enterprises and livelihood strategies pursued by poor farmers, the unemployed and working poor whilst preserving sensitive environments for future generations. Determining the future of food security is not the privilege of the few with economic clout or power to govern but the right of all. The incorporation of food sovereignty principles in policymaking is therefore paramount for achieving genuine long-term food security.
- Full Text:
- Authors: Hoepfl, Jason
- Date: 2020
- Subjects: Food sovereignty -- South Africa , Food security -- South Africa , Food security -- Government policy -- South Africa , Food security -- Climatic factors -- South Africa , Food policy -- Government policy -- South Africa , Agriculture and state -- South Africa , Food industry and trade -- Government policy -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/162851 , vital:40990
- Description: Food price volatility, ecological shocks and unprecedented levels of hunger and obesity are increasing concerns within food security governance, as is the emergence of food sovereignty in broadening critical discussions around food, water, energy and environmental crises. This thesis analyses this changing terrain in the context of South African policy. It analyses shifts in policymaking and the capability of South Africa’s food security policy frameworks to include food sovereignty principles and in so doing support genuine long-term food security. A shift in policy priorities from household production, trade and income opportunities towards social safety nets and nutritional interventions is identified. This focus is constrained by an inability to affect structural changes within a deeply inequitable food landscape. An emphasis on commercial farming and unwillingness to challenge large agribusiness, value chains and corporate retail has enabled social differentiation in access to food and the country’s colonial land dispensation to continue. Consequently, markets have continued to be antipathetic to the needs of poor producers and consumers in South Africa. To overcome these structural constraints, food security policy needs to be framed within a more radical normative agenda. This is important for challenging inequitable power relations and asserting the social and ecological imperatives of healthy food systems. Food sovereignty has significant potential to support a normative agenda by supporting the multiple farming practices, enterprises and livelihood strategies pursued by poor farmers, the unemployed and working poor whilst preserving sensitive environments for future generations. Determining the future of food security is not the privilege of the few with economic clout or power to govern but the right of all. The incorporation of food sovereignty principles in policymaking is therefore paramount for achieving genuine long-term food security.
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An analysis of the public reporting of organisational resilience found within the integrated reports of a large state-owned enterprise
- Authors: Fleming, Linda
- Date: 2020
- Subjects: Eskom (Firm) , Organizational resilience , Eskom (Firm) -- Management
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/141276 , vital:37958
- Description: This research explored whether there is any evidence of reporting of organisational resilience within the integrated reports of a large state-owned enterprise. The organisation chosen for the research was Eskom. The integrated annual reports of Eskom for 2016, 2017 and 2018 were examined. Direct and indirect evidence of organisational resilience was sought within the organisations integrated reports. The direct reporting of organisational resilience was located by using a PDF word search. A thematic content analysis was used to perform the search for indirect reporting of organisational resilience. Three main themes to represent organisational resilience that were identified beforehand were used to identify the indirect reporting of organisational resilience. Namely, transformability, adaptability and persistence. Sub themes of general and specified resilience were also identified during the research process. The literature review discusses the themes in detail, and also introduces communication and integrated reporting. Evidence of both direct and indirect organisational resilience was identified in all three years studied. Evidence of all the main themes and sub themes was found within the indirect reporting of organisational resilience. The main limitation of the study is that although evidence of reporting of organisational resilience was found, this evidence does not provide any indications of the level of organisational resilience within Eskom. A number of recommendations to Eskom management are made at the end of the research. What is interesting is that integrated reports are not designed to report on organisational resilience. However, the research showed clear evidence of reporting of organisational resilience within all three years researched. Potentially indicating that the integrated annual reports are a useful method of sharing information regarding organisational resilience with stakeholders. An additional benefit is that communication with stakeholders is simultaneously contributing to the enhancement of the organisations resilience.
- Full Text:
- Authors: Fleming, Linda
- Date: 2020
- Subjects: Eskom (Firm) , Organizational resilience , Eskom (Firm) -- Management
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/141276 , vital:37958
- Description: This research explored whether there is any evidence of reporting of organisational resilience within the integrated reports of a large state-owned enterprise. The organisation chosen for the research was Eskom. The integrated annual reports of Eskom for 2016, 2017 and 2018 were examined. Direct and indirect evidence of organisational resilience was sought within the organisations integrated reports. The direct reporting of organisational resilience was located by using a PDF word search. A thematic content analysis was used to perform the search for indirect reporting of organisational resilience. Three main themes to represent organisational resilience that were identified beforehand were used to identify the indirect reporting of organisational resilience. Namely, transformability, adaptability and persistence. Sub themes of general and specified resilience were also identified during the research process. The literature review discusses the themes in detail, and also introduces communication and integrated reporting. Evidence of both direct and indirect organisational resilience was identified in all three years studied. Evidence of all the main themes and sub themes was found within the indirect reporting of organisational resilience. The main limitation of the study is that although evidence of reporting of organisational resilience was found, this evidence does not provide any indications of the level of organisational resilience within Eskom. A number of recommendations to Eskom management are made at the end of the research. What is interesting is that integrated reports are not designed to report on organisational resilience. However, the research showed clear evidence of reporting of organisational resilience within all three years researched. Potentially indicating that the integrated annual reports are a useful method of sharing information regarding organisational resilience with stakeholders. An additional benefit is that communication with stakeholders is simultaneously contributing to the enhancement of the organisations resilience.
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An archetypical analysis of chief executive officers in the mining sector according to their remuneration and company performance: a resource based view
- Authors: King, Matthew Sebastian
- Date: 2020
- Subjects: Executives -- Salaries, etc. -- South Africa , Directors of corporations -- Salaries, etc. -- South Africa , Mining corporations -- Salaries, etc. -- South Africa , Mines and mineral resources -- Management
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/168503 , vital:41589
- Description: The growth in the mining sector post 1994 saw many CEO s enjoy exorbitant levels of financial prosperity particularly in relation to th e mining workforce . The pay disparity between the remuneration of CEO s and the average worker contributed to instability and labour unrest. While there has been extensive research conducted on the relationship between CEO remuneration and company performance, questions around the justification of exorbitant CEO remuneration levels have persisted. One of the shortcomings of these studies have been understanding company performance as limited to financial indicators. For this reason, Resource - Based theory was used in this study to focus on CEOs as tangible, heterogeneous and immobile assets, who could influence company performance by creating a firm’s competitive advantage. In order to investigate this, a mixed - method research design was utilised to ascertain the relationship between CEO remune ration and company performance. The data for the quantitative study was collected using an archival method by sourcing secondary data obtained from the sampled companie s’ annual integrated reports. Statistical tests were performed to test the relationsh ip between CEO remuneration and company performance of mining companies listed on the JSE over the period of 2014 to 2018. This was followed by the qualitative thematic analysis which utilised online information published about four CEOs sampled according to their pay/performance relationships (namely high earning/high performing; high earning/low performing; low earning/high performing and low earning/low performing). The VRIO framework was utilised in conjunction with the thematic analysis to assess the extent to which each of the selected CEOs could be identified as valuable, rare, inimitable and organised. Finally, t he demographic characteristics and leadership attributes of these CEOs were collectiv ely aligned to particular l eadership archetype s. This study found that despite company performance levels experiencing negative growth and volatility, CEO remuneration remained stable and experienced positive growth throughout the period . The qualitative analysis and the application of the VRIO framework wa s conducted in order to explor e reasons why this disparity may continue to exist. The analysis of the differences in demographic characteristics and leadership attributes between these four CEOs provided a possible j ustification for the disparity in t he levels of remuneration. It was found that some CEOs high levels of remuneration could be justified by virtue of their well - developed leadership skills. In particular CEOs need softer skills (such as communication, openness, relationship - building and stakeholder engagement) and to draw on the communicator, builder and coach archetypes in order to create a sustained competitive advantage within companies.
- Full Text:
- Authors: King, Matthew Sebastian
- Date: 2020
- Subjects: Executives -- Salaries, etc. -- South Africa , Directors of corporations -- Salaries, etc. -- South Africa , Mining corporations -- Salaries, etc. -- South Africa , Mines and mineral resources -- Management
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/168503 , vital:41589
- Description: The growth in the mining sector post 1994 saw many CEO s enjoy exorbitant levels of financial prosperity particularly in relation to th e mining workforce . The pay disparity between the remuneration of CEO s and the average worker contributed to instability and labour unrest. While there has been extensive research conducted on the relationship between CEO remuneration and company performance, questions around the justification of exorbitant CEO remuneration levels have persisted. One of the shortcomings of these studies have been understanding company performance as limited to financial indicators. For this reason, Resource - Based theory was used in this study to focus on CEOs as tangible, heterogeneous and immobile assets, who could influence company performance by creating a firm’s competitive advantage. In order to investigate this, a mixed - method research design was utilised to ascertain the relationship between CEO remune ration and company performance. The data for the quantitative study was collected using an archival method by sourcing secondary data obtained from the sampled companie s’ annual integrated reports. Statistical tests were performed to test the relationsh ip between CEO remuneration and company performance of mining companies listed on the JSE over the period of 2014 to 2018. This was followed by the qualitative thematic analysis which utilised online information published about four CEOs sampled according to their pay/performance relationships (namely high earning/high performing; high earning/low performing; low earning/high performing and low earning/low performing). The VRIO framework was utilised in conjunction with the thematic analysis to assess the extent to which each of the selected CEOs could be identified as valuable, rare, inimitable and organised. Finally, t he demographic characteristics and leadership attributes of these CEOs were collectiv ely aligned to particular l eadership archetype s. This study found that despite company performance levels experiencing negative growth and volatility, CEO remuneration remained stable and experienced positive growth throughout the period . The qualitative analysis and the application of the VRIO framework wa s conducted in order to explor e reasons why this disparity may continue to exist. The analysis of the differences in demographic characteristics and leadership attributes between these four CEOs provided a possible j ustification for the disparity in t he levels of remuneration. It was found that some CEOs high levels of remuneration could be justified by virtue of their well - developed leadership skills. In particular CEOs need softer skills (such as communication, openness, relationship - building and stakeholder engagement) and to draw on the communicator, builder and coach archetypes in order to create a sustained competitive advantage within companies.
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An assessment of temporal changes in selective biological characteristics of chokka squid (Loligo reynaudii d’Órbigny, 1845)
- Authors: Mmethi, Mpho Audrey
- Date: 2020
- Subjects: Loligo reynaudii , Squids -- Morphology , Squids -- South Africa , Squid fisheries -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143516 , vital:38253
- Description: The biological characteristics of chokka squid, Loligo reynaudii, sampled off the south coast of South Africa, were compared between 1994 and 2017 to ascertain any temporal changes using analysis of length frequency (LF) data over 15 years (1996–2017), and mantle length (ML) and total weight (TW) relationships over 9 years (1994–2016). To investigate feeding, two caecum colours were chosen for analysis (white: no food ingested, and yellow: six to seven hours after food ingestion). Other factors were kept constant throughout: similar sampling period of 60 days in spring-summer, similar depths and areas sampled, and identical maturity stage. Anecdotal evidence from fishers suggested that the length frequency and ML_TW relationship of chokka have changed over years, with possibilities to be linked to fishing activities and environmental conditions. Also, there is evidence in the published literature that both fisheries and environment may influence length distributions in populations of fish and cephalopods over time. The results from this study showed no significant differences between length frequencies over the time series. However, a significant decrease in length frequencies between 2014 and 2016 was noted when paired data was analysed by Anova (2014:2015, 2014:2016 and 2015:2016), which was initially noted in kernel density, Figure 2, hence an additional analysis was done. These changes were not linked to sea temperature (at 9 m, 14 m, 18 m, and 21 m depth strata), with not significant (P>0.05) results when temperature was analysed by t-test between 2002 and 2015. There was also a weak correlation between length frequency and the total squid catch in a given year (F Statistic (df = 1; 13) is 3.686 and 5.394 for males and females respectively, R² is 0.221 for males and 0.293 for females), but too weak to interpret, given the lack of other supporting data and the short time series. The ML_TW relationship showed no significant trends between the years for either sex. There was also no correlation between the ML_TW and total squid catch or temperature. A white caecum occurred significantly more often in males than in females (dof = 1; p < 0.05) from General Linear Model (GLM), indicating that the presence of non-feeding males in the spawning grounds may be linked to the behaviour of spawning squid.
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- Authors: Mmethi, Mpho Audrey
- Date: 2020
- Subjects: Loligo reynaudii , Squids -- Morphology , Squids -- South Africa , Squid fisheries -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143516 , vital:38253
- Description: The biological characteristics of chokka squid, Loligo reynaudii, sampled off the south coast of South Africa, were compared between 1994 and 2017 to ascertain any temporal changes using analysis of length frequency (LF) data over 15 years (1996–2017), and mantle length (ML) and total weight (TW) relationships over 9 years (1994–2016). To investigate feeding, two caecum colours were chosen for analysis (white: no food ingested, and yellow: six to seven hours after food ingestion). Other factors were kept constant throughout: similar sampling period of 60 days in spring-summer, similar depths and areas sampled, and identical maturity stage. Anecdotal evidence from fishers suggested that the length frequency and ML_TW relationship of chokka have changed over years, with possibilities to be linked to fishing activities and environmental conditions. Also, there is evidence in the published literature that both fisheries and environment may influence length distributions in populations of fish and cephalopods over time. The results from this study showed no significant differences between length frequencies over the time series. However, a significant decrease in length frequencies between 2014 and 2016 was noted when paired data was analysed by Anova (2014:2015, 2014:2016 and 2015:2016), which was initially noted in kernel density, Figure 2, hence an additional analysis was done. These changes were not linked to sea temperature (at 9 m, 14 m, 18 m, and 21 m depth strata), with not significant (P>0.05) results when temperature was analysed by t-test between 2002 and 2015. There was also a weak correlation between length frequency and the total squid catch in a given year (F Statistic (df = 1; 13) is 3.686 and 5.394 for males and females respectively, R² is 0.221 for males and 0.293 for females), but too weak to interpret, given the lack of other supporting data and the short time series. The ML_TW relationship showed no significant trends between the years for either sex. There was also no correlation between the ML_TW and total squid catch or temperature. A white caecum occurred significantly more often in males than in females (dof = 1; p < 0.05) from General Linear Model (GLM), indicating that the presence of non-feeding males in the spawning grounds may be linked to the behaviour of spawning squid.
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An assessment of the effectiveness of the Crossways Farm Village constructed wetland in the treatment of domestic wastewater
- Authors: Silbernagl, Ryan
- Date: 2020
- Subjects: Crossways Farm Village FWS wetland (South Africa)-- Management , Sewage -- Purification -- South Africa , Wetland management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145011 , vital:38400
- Description: A mass balance study was conducted comparing inflowing and outflowing solute loads in order to calculate the treatment efficiency of a free water surface (FWS) constructed wetland used to treat domestic wastewater following primary treatment in an anaerobic reactor and oxidation in a rotating biological contractor. Water samples were taken at six locations down the length of the treatment system and analysed for nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), ammonia nitrogen (NH4-N) and phosphorus as phosphate (PO4-P). Flow was determined using two V notch weirs combined with pressure transducers based on an empirically derived stage-discharge relationship. The concentration of each solute (g.m-3) multiplied by flow (m3.day-1) provides a measurement of the mass of each solute entering and leaving the treatment wetland such that the difference (inflow – outflow) indicates the nett storage in, or loss from, the wetland. In order to determine the water balance, apart from measuring surface inflows and outflows, rainfall was measured using an onsite rain gauge. Evapotranspirational losses were determined using the Penman-Monteith equation based on weather data collected at an onsite weather station. Other than water that entered the wetland via the primary water treatment works, surface inflows could be ignored as the wetland was sealed with a plastic liner, which also prevented groundwater inflow and outflow. Wetland outputs via surface outflow and evapotranspiration were then subtracted from wetland inputs to determine the water balance over the study period. Approximately 10.5% of water inputs into the hydrological mass balance calculation was not accounted for, which is considered to be accounted for by inaccuracy associated with the estimation of evapotranspiration and possibly by differences in water levels in the wetland at the start and end of the experiment. Total input, output and storage of NO3-N, NO2-N, NH4-N and PO4-P was calculated from April 2016 to September 2016 to give the treatment efficiency of the FWS wetland system. Results showed a 91.5% reduction in NO3-N, 76.6% reduction in NH4-N, and 88.8% reduction in PO4P between the inflow and outflow. Wetland sediment and vegetation (Typha capensis) samples were also analysed for nitrogen and phosphorus content to give an estimate of nutrient stocks/storage accumulated in plant tissues and sediments over the lifespan of the wetland. Standing stock calculations showed that a total of 450.1kg of nitrogen is stored in the wetlands, of which 69.3kg is stored in wetland sediments. Wetland phosphorus retention was found to be significantly lower with a total of 57.1kg of phosphorus, of which 77.4% was stored in sediments, indicating that wetland sediments comprise the largest store and therefore removal pathway of nutrients in the Crossways Farm Village FWS wetland.
- Full Text:
- Authors: Silbernagl, Ryan
- Date: 2020
- Subjects: Crossways Farm Village FWS wetland (South Africa)-- Management , Sewage -- Purification -- South Africa , Wetland management -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/145011 , vital:38400
- Description: A mass balance study was conducted comparing inflowing and outflowing solute loads in order to calculate the treatment efficiency of a free water surface (FWS) constructed wetland used to treat domestic wastewater following primary treatment in an anaerobic reactor and oxidation in a rotating biological contractor. Water samples were taken at six locations down the length of the treatment system and analysed for nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), ammonia nitrogen (NH4-N) and phosphorus as phosphate (PO4-P). Flow was determined using two V notch weirs combined with pressure transducers based on an empirically derived stage-discharge relationship. The concentration of each solute (g.m-3) multiplied by flow (m3.day-1) provides a measurement of the mass of each solute entering and leaving the treatment wetland such that the difference (inflow – outflow) indicates the nett storage in, or loss from, the wetland. In order to determine the water balance, apart from measuring surface inflows and outflows, rainfall was measured using an onsite rain gauge. Evapotranspirational losses were determined using the Penman-Monteith equation based on weather data collected at an onsite weather station. Other than water that entered the wetland via the primary water treatment works, surface inflows could be ignored as the wetland was sealed with a plastic liner, which also prevented groundwater inflow and outflow. Wetland outputs via surface outflow and evapotranspiration were then subtracted from wetland inputs to determine the water balance over the study period. Approximately 10.5% of water inputs into the hydrological mass balance calculation was not accounted for, which is considered to be accounted for by inaccuracy associated with the estimation of evapotranspiration and possibly by differences in water levels in the wetland at the start and end of the experiment. Total input, output and storage of NO3-N, NO2-N, NH4-N and PO4-P was calculated from April 2016 to September 2016 to give the treatment efficiency of the FWS wetland system. Results showed a 91.5% reduction in NO3-N, 76.6% reduction in NH4-N, and 88.8% reduction in PO4P between the inflow and outflow. Wetland sediment and vegetation (Typha capensis) samples were also analysed for nitrogen and phosphorus content to give an estimate of nutrient stocks/storage accumulated in plant tissues and sediments over the lifespan of the wetland. Standing stock calculations showed that a total of 450.1kg of nitrogen is stored in the wetlands, of which 69.3kg is stored in wetland sediments. Wetland phosphorus retention was found to be significantly lower with a total of 57.1kg of phosphorus, of which 77.4% was stored in sediments, indicating that wetland sediments comprise the largest store and therefore removal pathway of nutrients in the Crossways Farm Village FWS wetland.
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An effort to study the influence of tides on the longitudinal variation of vertical E× B drift over the African sector:
- Habyarimana, Valence, Habarulema, John B, Mungufeni, Patrick, Uwamahoro, Jean C
- Authors: Habyarimana, Valence , Habarulema, John B , Mungufeni, Patrick , Uwamahoro, Jean C
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149026 , vital:38797 , https://doi.org/10.1016/j.jastp.2020.105338
- Description: Meteorological processes such as tides influence ionospheric variability through vertical coupling. For the first time, we have used data from Communication Navigation Outage and Forecasting System (C/NOFS) satellite from 2008–2015 to develop a Neural Network (NN) vertical E×B drift model over the African region, with inclusion of a proxy of tides as one of the inputs together with other physical and geophysical inputs. Two models (with and without tidal proxy input) were developed for both East and West African sectors. To derive the tidal proxy, we first calculate the 60-day running means per year which were subtracted from the actual vertical E×B drift measurements to obtain a set of residuals. The purpose of the subtraction was to remove long-term trends in vertical E×B drift that could potentially alias into tides.
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- Authors: Habyarimana, Valence , Habarulema, John B , Mungufeni, Patrick , Uwamahoro, Jean C
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149026 , vital:38797 , https://doi.org/10.1016/j.jastp.2020.105338
- Description: Meteorological processes such as tides influence ionospheric variability through vertical coupling. For the first time, we have used data from Communication Navigation Outage and Forecasting System (C/NOFS) satellite from 2008–2015 to develop a Neural Network (NN) vertical E×B drift model over the African region, with inclusion of a proxy of tides as one of the inputs together with other physical and geophysical inputs. Two models (with and without tidal proxy input) were developed for both East and West African sectors. To derive the tidal proxy, we first calculate the 60-day running means per year which were subtracted from the actual vertical E×B drift measurements to obtain a set of residuals. The purpose of the subtraction was to remove long-term trends in vertical E×B drift that could potentially alias into tides.
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