The proprietary consequences of foreign marriages for the purposes of estate planning and succession in South Africa
- Authors: Thorne, Aimee Liza
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/420725 , vital:71773
- Description: This thesis is intended to provide clarity regarding the proprietary consequences of foreign marriages in the context of estate planning and succession in South Africa. It includes an exploration into the impact of specific legislation on foreign marriages, the implications of matrimonial property regimes on a deceased estate in South Africa, private international law principles affecting matrimonial property and succession claims, the scope of antenuptial contracts and postnuptial contracts as existing remedies for foreign remedies, and the harmonisation of succession and matrimonial property law in the European Union (EU). It furthermore suggests potential reforms for the overhaul of the lex domicilii matrimonii principle and associated issues arising therefrom. Various specific issues discussed include the waiver of accrual claims, maintenance claims by surviving spouses of a foreign marriage, choice-of-law rules for matrimonial property rights and succession rights, the registration of a domestic or foreign antenuptial contract for foreign marriages, the formal validity and proper law of antenuptial contracts, the operation of the immutability principle on a domestic and international level, and the common-law approach to the recognition of postnuptial contracts and spousal donations. , Thesis (LLM) -- Faculty of Law, Law, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Thorne, Aimee Liza
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/420725 , vital:71773
- Description: This thesis is intended to provide clarity regarding the proprietary consequences of foreign marriages in the context of estate planning and succession in South Africa. It includes an exploration into the impact of specific legislation on foreign marriages, the implications of matrimonial property regimes on a deceased estate in South Africa, private international law principles affecting matrimonial property and succession claims, the scope of antenuptial contracts and postnuptial contracts as existing remedies for foreign remedies, and the harmonisation of succession and matrimonial property law in the European Union (EU). It furthermore suggests potential reforms for the overhaul of the lex domicilii matrimonii principle and associated issues arising therefrom. Various specific issues discussed include the waiver of accrual claims, maintenance claims by surviving spouses of a foreign marriage, choice-of-law rules for matrimonial property rights and succession rights, the registration of a domestic or foreign antenuptial contract for foreign marriages, the formal validity and proper law of antenuptial contracts, the operation of the immutability principle on a domestic and international level, and the common-law approach to the recognition of postnuptial contracts and spousal donations. , Thesis (LLM) -- Faculty of Law, Law, 2023
- Full Text:
- Date Issued: 2023-03-29
Evaluation of spatial distribution and health risk of pesticide residues in the environmental matrices of buffalo river estuary and their removal using nanosponges and modified cyclodextrins
- Authors: Mdeni, Nonkululeko Landy
- Date: 2023-03
- Subjects: Chemicals , Hazardous substances , Dangerous chemicals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27629 , vital:69321
- Description: The contamination of lotic ecosystems caused by agricultural, industrial, and anthropogenic activities has attracted the attention of researchers, authorities, and scientists because these waterbodies are of social and economic importance to human livelihoods. Pesticides and insecticides are a group of compounds that are toxic to pests and insects, respectively. Organophosphate pesticides (OPs) can be released into different environmental matrices through several sources including agricultural and urban runoff. They are one of the three main classes of synthetic organic pesticides that are used in agricultural sector and very often end up in other destinations than their target sites. In this study, four OPs, namely, ronnel, malathion, parathion and Durban were investigated. The Buffalo River Estuary, located in East London, is one of most popular areas and the river is a major source of raw water abstraction for three municipalities in the Eastern Cape Province, South Africa. Sediment samples were collected from six points in the estuary and soil samples were taken from a nearby dumpsite in winter and spring seasons of 2021. The physicochemical parameters of the samples including particle size, moisture content, oil and grease and organic carbon were determined. The samples were then extracted by ultra-sonication, the final extracts were analyzed using GC-μECD and the risk quotient (RQ) method was used to evaluate the risk of OP exposure to aquatic organisms. Polymer modified cyclodextrin (β-CD) for the removal of parathion in sediment and soil was synthesized and the morphology of the modified β-CD and vibrations of the synthesized material were determined using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of the OPs investigated were in the range of 0.09 to 2.99 and 0.274 to 9.06 μg/L, respectively. OPs gave a good recovery except for malathion, which had a recovery percentage lower than 70%. Calibration curves were plotted for the four OPs and were linear with relative standard deviations (RSD) ranging from 1.02 to 3.50, and correlation coefficients (R2) ranging from 0.9935 to 0.9972. The mean concentrations for sediments and soil in both seasons varied from 0.00231 to 63.8 μg/g in winter and from 0.0017 to 36.6 μg/g in spring, with malathion being the predominant congener and dursban being the least dominant in both seasons. In winter, the particle size percentages of the sediment and soil samples ranged from 34.4 to 79.4 percentage, 15.4 to 23.9 percentage and from 7.77 to 38.3 percentage for coarse, medium, and fine fractions, respectively. While in spring, the particle size for the course, medium and fine mesh fractions ranged from 37.4 to 74.6 percentage, 14.1 to 25.1 percentage and 12.4 to 35.0 percentage respectively; the percentage moisture content varied from 43.0 to 73.1 in winter, and from 57.1 to 63.4 in spring. In the soil samples, the physicochemical properties were lower in winter except for the n- hexane extractable material (HEM), which significantly decreased in spring from 2.6 to 1.63 mg/kg; while for sediments, the oil and grease ranged from 1.77 to 10.3 mg/kg in winter and from 1.63 to 4.28 mg/kg in spring. The risk quotient method was used to determine the risk of OP exposure to sediment-dwelling organisms and the results obtained indicated that the levels of OPs in this study, especially dursban, can pose a high risk to the organisms in sediments, with RQs higher than ten (˃10) in both winter and summer. The Pearson product-moment correlation showed that parathion had a weak correlation with every other variable except for malathion in winter, whereas in spring, parathion correlated very weakly with malathion; suggesting that products containing parathion are mostly used to control pests found in crops, such as corn and mosquitos, which are most active in the spring season. There was a very strong correlation between dursban and ronnel in spring and winter, implying that an increase in dursban concentration resulted in an increase in the concentration of ronnel. To determine the efficiency of the synthesized adsorbent CD-chitosan-alginate for the removal of Parathion from soil and sediment, different parameters such as concentration, time, pH and dose were varied. The adsorption capacity was found to be highest at pH 2 (99.19 percentage), when 3 mL of the adsorbent was used for 30 minutes. , Thesis (Msci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
- Authors: Mdeni, Nonkululeko Landy
- Date: 2023-03
- Subjects: Chemicals , Hazardous substances , Dangerous chemicals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27629 , vital:69321
- Description: The contamination of lotic ecosystems caused by agricultural, industrial, and anthropogenic activities has attracted the attention of researchers, authorities, and scientists because these waterbodies are of social and economic importance to human livelihoods. Pesticides and insecticides are a group of compounds that are toxic to pests and insects, respectively. Organophosphate pesticides (OPs) can be released into different environmental matrices through several sources including agricultural and urban runoff. They are one of the three main classes of synthetic organic pesticides that are used in agricultural sector and very often end up in other destinations than their target sites. In this study, four OPs, namely, ronnel, malathion, parathion and Durban were investigated. The Buffalo River Estuary, located in East London, is one of most popular areas and the river is a major source of raw water abstraction for three municipalities in the Eastern Cape Province, South Africa. Sediment samples were collected from six points in the estuary and soil samples were taken from a nearby dumpsite in winter and spring seasons of 2021. The physicochemical parameters of the samples including particle size, moisture content, oil and grease and organic carbon were determined. The samples were then extracted by ultra-sonication, the final extracts were analyzed using GC-μECD and the risk quotient (RQ) method was used to evaluate the risk of OP exposure to aquatic organisms. Polymer modified cyclodextrin (β-CD) for the removal of parathion in sediment and soil was synthesized and the morphology of the modified β-CD and vibrations of the synthesized material were determined using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of the OPs investigated were in the range of 0.09 to 2.99 and 0.274 to 9.06 μg/L, respectively. OPs gave a good recovery except for malathion, which had a recovery percentage lower than 70%. Calibration curves were plotted for the four OPs and were linear with relative standard deviations (RSD) ranging from 1.02 to 3.50, and correlation coefficients (R2) ranging from 0.9935 to 0.9972. The mean concentrations for sediments and soil in both seasons varied from 0.00231 to 63.8 μg/g in winter and from 0.0017 to 36.6 μg/g in spring, with malathion being the predominant congener and dursban being the least dominant in both seasons. In winter, the particle size percentages of the sediment and soil samples ranged from 34.4 to 79.4 percentage, 15.4 to 23.9 percentage and from 7.77 to 38.3 percentage for coarse, medium, and fine fractions, respectively. While in spring, the particle size for the course, medium and fine mesh fractions ranged from 37.4 to 74.6 percentage, 14.1 to 25.1 percentage and 12.4 to 35.0 percentage respectively; the percentage moisture content varied from 43.0 to 73.1 in winter, and from 57.1 to 63.4 in spring. In the soil samples, the physicochemical properties were lower in winter except for the n- hexane extractable material (HEM), which significantly decreased in spring from 2.6 to 1.63 mg/kg; while for sediments, the oil and grease ranged from 1.77 to 10.3 mg/kg in winter and from 1.63 to 4.28 mg/kg in spring. The risk quotient method was used to determine the risk of OP exposure to sediment-dwelling organisms and the results obtained indicated that the levels of OPs in this study, especially dursban, can pose a high risk to the organisms in sediments, with RQs higher than ten (˃10) in both winter and summer. The Pearson product-moment correlation showed that parathion had a weak correlation with every other variable except for malathion in winter, whereas in spring, parathion correlated very weakly with malathion; suggesting that products containing parathion are mostly used to control pests found in crops, such as corn and mosquitos, which are most active in the spring season. There was a very strong correlation between dursban and ronnel in spring and winter, implying that an increase in dursban concentration resulted in an increase in the concentration of ronnel. To determine the efficiency of the synthesized adsorbent CD-chitosan-alginate for the removal of Parathion from soil and sediment, different parameters such as concentration, time, pH and dose were varied. The adsorption capacity was found to be highest at pH 2 (99.19 percentage), when 3 mL of the adsorbent was used for 30 minutes. , Thesis (Msci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
Evaluation of water and sanitation challenges in informal settlements: a case study of Duncan Village, East London, South Africa
- Authors: Munyai, Khodani Keith
- Date: 2023-03
- Subjects: Squatter settlements , Water quality management , Sanitation, Rural
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27721 , vital:69396
- Description: Water and sanitation are basic human needs. It is also a constitutional right for all citizens in South Africa to have access to both water and sanitation. Supply of water and sanitation services in South Africa is characterised by both achievements and challenges. As informed by literature, in South Africa it is evident that water and sanitation still hold many challenges in poor communities, particularly in informal settlements. This study was conducted with the purpose of evaluating water and sanitation challenges in the informal settlements of Duncan Village and make recommendations, where applicable, to the local municipality for possible remedies. Despite the provision of water and sanitation by the Buffalo City Metro Municipality, the study reveals that there are serious water and sanitation challenges in Duncan Village. High water losses, illegal water connections, illegal sanitation connections causing sewer spillages, vandalism of both water and sanitation service infrastructure, and lack of operations and maintenance are identified as the key water and sanitation challenges. According to the findings, the causes of these challenges include the municipality's lack of proper planning for informal settlements; lack of visibility of municipal water and sanitation officials in informal settlements; lack of awareness; lack of public participation; overpopulation; lack of monitoring; and lack of operations and maintenance budget to help keep the provided facilities intact and usable. The study's key recommendations include intense involvement of the municipality and the ward councillors, ownership by the residents, monitoring of water and sanitation facilities, operations and maintenance, and formalising Duncan Village informal settlements. This was accomplished using questionnaires to gather, analyse, and interpret the collected data. The study targeted residents, ward councillors, and a municipal officer from the municipality's Water and Sanitation section as respondents , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
- Authors: Munyai, Khodani Keith
- Date: 2023-03
- Subjects: Squatter settlements , Water quality management , Sanitation, Rural
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27721 , vital:69396
- Description: Water and sanitation are basic human needs. It is also a constitutional right for all citizens in South Africa to have access to both water and sanitation. Supply of water and sanitation services in South Africa is characterised by both achievements and challenges. As informed by literature, in South Africa it is evident that water and sanitation still hold many challenges in poor communities, particularly in informal settlements. This study was conducted with the purpose of evaluating water and sanitation challenges in the informal settlements of Duncan Village and make recommendations, where applicable, to the local municipality for possible remedies. Despite the provision of water and sanitation by the Buffalo City Metro Municipality, the study reveals that there are serious water and sanitation challenges in Duncan Village. High water losses, illegal water connections, illegal sanitation connections causing sewer spillages, vandalism of both water and sanitation service infrastructure, and lack of operations and maintenance are identified as the key water and sanitation challenges. According to the findings, the causes of these challenges include the municipality's lack of proper planning for informal settlements; lack of visibility of municipal water and sanitation officials in informal settlements; lack of awareness; lack of public participation; overpopulation; lack of monitoring; and lack of operations and maintenance budget to help keep the provided facilities intact and usable. The study's key recommendations include intense involvement of the municipality and the ward councillors, ownership by the residents, monitoring of water and sanitation facilities, operations and maintenance, and formalising Duncan Village informal settlements. This was accomplished using questionnaires to gather, analyse, and interpret the collected data. The study targeted residents, ward councillors, and a municipal officer from the municipality's Water and Sanitation section as respondents , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
Participation dynamics in the management of protected areas: the case of Dwesa-Cwebe Nature Reserve and its adjacent communities, Eastern Cape Province, South Africa
- Nyamahono, James Donald https://orcid.org/0000-0002-1391-9126
- Authors: Nyamahono, James Donald https://orcid.org/0000-0002-1391-9126
- Date: 2023-03
- Subjects: Protected areas , Natural resources conservation areas -- South Africa , National protected areas systems
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27358 , vital:66947
- Description: In many parts of the developing world, participation in the management of ‘protected areas’ is among the most tangible indices of how the rural population encounters formal conservation policies, strategies and ideologies. However, some scholars have argued that the sharing of the burdens and benefits of participation is devoid of equity. While some analysts have emphasised the imperative of multi-stakeholder participation in nature conservation, citing this as a crucial socio-ecological investment, others have highlighted the inherent contradictions in the process, describing it as an avenue for manipulation, tokenism and exploitation. This study is located in this debate and focuses on narratives around the participation of different stakeholders in the management of Dwesa-Cwebe Nature Reserve and its adjacent communities in the rural Wild-Coast, Eastern Cape, South Africa. The researcher notes that research on the degrees and participation dynamics among various role players involved in the management of protected areas in South Africa, Dwesa-Cwebe Nature Reserve in particular is limited. Against this background, this study contributes to ongoing discussions on protected area management in South Africa but seeks to expand this discussion by interrogating the nature and degrees of participation within the Dwesa-Cwebe Nature Reserve - to deepen intellectual understanding on the significant role played by protected areas in engendering participatory democracy, equity, justice as well as meeting the needs of marginalised communities. Primary data for the thesis were collected using in-depth and key-informant interviews with officials from government institutions and parastatals, politicians and traditional authority figures. Focus group discussions were held with ‘youth’ participants as well as ‘elders’ in the Reserve’s adjacent communities. An analysis of policy and other government documents sought to outline the institutional attributes of protected areas management in South Africa and the underpinning ideas. A thematic analysis of the corpus of empirical information helped to show how these institutional attributes inhere in Dwesa-Cwebe Nature Reserve as well as the epistemic challenge these attributes pose vis-à-vis indigenous ecological ideas and practices in the adjacent ‘indigenous’ communities. The study revealed that participation is perceived differently by various stakeholders due to multiple, mutually contradictory impulses. While institutional stakeholders attached great importance to the structural role of institutional frameworks, hence the vigorous reliance on formal conservation strategies, narratives from community members drew attention to ‘equity deficits’. The study also found that while the selected Reserve may have fostered cooperation between government and the adjacent communities, conflict and distrust ran deep between these stakeholders. From these and other findings, the study concluded that ecological participation in the study area was characterised by clusters of stakeholders who regard one another as ‘epistemic outsiders’ and related to one another as such, with practical consequences – especially for the long-term sustainability of the Reserve. In the main, the thesis rests on the argument that in the face of epistemic differences, dominance and marginalisation could become a defining feature of protected area management that cannot be readily resolved through the mere process of participation. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2023
- Full Text:
- Date Issued: 2023-03
- Authors: Nyamahono, James Donald https://orcid.org/0000-0002-1391-9126
- Date: 2023-03
- Subjects: Protected areas , Natural resources conservation areas -- South Africa , National protected areas systems
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27358 , vital:66947
- Description: In many parts of the developing world, participation in the management of ‘protected areas’ is among the most tangible indices of how the rural population encounters formal conservation policies, strategies and ideologies. However, some scholars have argued that the sharing of the burdens and benefits of participation is devoid of equity. While some analysts have emphasised the imperative of multi-stakeholder participation in nature conservation, citing this as a crucial socio-ecological investment, others have highlighted the inherent contradictions in the process, describing it as an avenue for manipulation, tokenism and exploitation. This study is located in this debate and focuses on narratives around the participation of different stakeholders in the management of Dwesa-Cwebe Nature Reserve and its adjacent communities in the rural Wild-Coast, Eastern Cape, South Africa. The researcher notes that research on the degrees and participation dynamics among various role players involved in the management of protected areas in South Africa, Dwesa-Cwebe Nature Reserve in particular is limited. Against this background, this study contributes to ongoing discussions on protected area management in South Africa but seeks to expand this discussion by interrogating the nature and degrees of participation within the Dwesa-Cwebe Nature Reserve - to deepen intellectual understanding on the significant role played by protected areas in engendering participatory democracy, equity, justice as well as meeting the needs of marginalised communities. Primary data for the thesis were collected using in-depth and key-informant interviews with officials from government institutions and parastatals, politicians and traditional authority figures. Focus group discussions were held with ‘youth’ participants as well as ‘elders’ in the Reserve’s adjacent communities. An analysis of policy and other government documents sought to outline the institutional attributes of protected areas management in South Africa and the underpinning ideas. A thematic analysis of the corpus of empirical information helped to show how these institutional attributes inhere in Dwesa-Cwebe Nature Reserve as well as the epistemic challenge these attributes pose vis-à-vis indigenous ecological ideas and practices in the adjacent ‘indigenous’ communities. The study revealed that participation is perceived differently by various stakeholders due to multiple, mutually contradictory impulses. While institutional stakeholders attached great importance to the structural role of institutional frameworks, hence the vigorous reliance on formal conservation strategies, narratives from community members drew attention to ‘equity deficits’. The study also found that while the selected Reserve may have fostered cooperation between government and the adjacent communities, conflict and distrust ran deep between these stakeholders. From these and other findings, the study concluded that ecological participation in the study area was characterised by clusters of stakeholders who regard one another as ‘epistemic outsiders’ and related to one another as such, with practical consequences – especially for the long-term sustainability of the Reserve. In the main, the thesis rests on the argument that in the face of epistemic differences, dominance and marginalisation could become a defining feature of protected area management that cannot be readily resolved through the mere process of participation. , Thesis (PhD) -- Faculty of Social Sciences and Humanities, 2023
- Full Text:
- Date Issued: 2023-03
Analysis of corporate failures: a case study of two South African banks
- Mqomboti, Xitshembiso Pronacia
- Authors: Mqomboti, Xitshembiso Pronacia
- Date: 2023-02
- Subjects: Business failures South Africa , Corporate governance South Africa , Risk management , Operational risk , Business ethics , Bank management South Africa , Banks and banking South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419151 , vital:71620
- Description: This study analysed the factors that contributed to the failure of Venda Building Society Mutual Bank (VBS) and African Bank Limited and the impact it had on their key stakeholders. The specific objectives of this study were to evaluate African Bank and VBS bank's operational risk management processes and controls, the role of ethical failures at VBS bank and African Bank; and assess how the failures affected their stakeholders. The population sample of the study included African Bank and VBS. The study adopted a qualitative research method. Existing reports from both African Bank and VBS were used to collect data. The study adopted a thematic data analysis method, which includes data coding and the development of themes. The data analysis framework was derived from a defined set of research propositions and seven (7) themes were derived from this analysis method. The failure in operational controls of both banks and ineffective risk management structures including unethical conduct by the executive management and board of VBS bank, irregular financial transactions and weakened external auditing function resulted in an unaccountable executive relationship and reckless lending decision-making. This research study will expand on the existing body of knowledge on the failures and near-failures of banks in the South African banking sector. The South African banking industry and its regulatory bodies will be better equipped to strengthen their corporate governance in risk controls to mitigate future collapses and near collapses of banks. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2023
- Full Text:
- Date Issued: 2023-02
- Authors: Mqomboti, Xitshembiso Pronacia
- Date: 2023-02
- Subjects: Business failures South Africa , Corporate governance South Africa , Risk management , Operational risk , Business ethics , Bank management South Africa , Banks and banking South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419151 , vital:71620
- Description: This study analysed the factors that contributed to the failure of Venda Building Society Mutual Bank (VBS) and African Bank Limited and the impact it had on their key stakeholders. The specific objectives of this study were to evaluate African Bank and VBS bank's operational risk management processes and controls, the role of ethical failures at VBS bank and African Bank; and assess how the failures affected their stakeholders. The population sample of the study included African Bank and VBS. The study adopted a qualitative research method. Existing reports from both African Bank and VBS were used to collect data. The study adopted a thematic data analysis method, which includes data coding and the development of themes. The data analysis framework was derived from a defined set of research propositions and seven (7) themes were derived from this analysis method. The failure in operational controls of both banks and ineffective risk management structures including unethical conduct by the executive management and board of VBS bank, irregular financial transactions and weakened external auditing function resulted in an unaccountable executive relationship and reckless lending decision-making. This research study will expand on the existing body of knowledge on the failures and near-failures of banks in the South African banking sector. The South African banking industry and its regulatory bodies will be better equipped to strengthen their corporate governance in risk controls to mitigate future collapses and near collapses of banks. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2023
- Full Text:
- Date Issued: 2023-02
Design and development of mobile-based e-Marketing application for communal farmers in Eastern Cape. South Africa.
- Authors: Fatumo, Dare Ebenezer
- Date: 2023-02
- Subjects: Food security , Agriculture , Agriculture -- Technology transfer
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27511 , vital:67421
- Description: The application of Information and Communication Technologies (ICT) in agriculture can augment farmers' production capabilities, this is a perception for all farmers worldwide, but there are some in communal areas who may not be as exposed to ICT tools as their commercial counterparts in urban areas, especially in developed communities. Food security in any society is a vital measure that should always be treated with high priority since humankind's existence is based on food availability. One major challenge with farmers in communal areas has been the marketing of their farm produce effectively to avoid wastage, get more value, and bridge the gap between themselves and urban commercial farmers. This challenge includes food wastage, untimely information, and market accessibility due to distance restraint. ICT can beused to bring a functional platform to assist this challenge. In this context, communal farmers have a challenge. The aim of this research was to design and develop an easy-to-use mobilebased e-marketing application for marketing farm products for communal farmers in Alice community, South Africa. Before design and development, review of challenges of farmers on the reception and communication of sensitive information pertaining to food security. Effective communication of farm produce baseline information on awareness and adaptation of mobile ICT technology of communal farmers was investigated. A mixed method was used through reviews of literature and as well distribution of questionnaires to get an understanding of the present state of communal farmers’ marketing problems. Furthermore, a prototyping methodology was used in the development of the mobile-based application for this research. The result of this research demonstrated the need for communal farmers to market their farm products at their convenience. An easy-to-use mobile-based e-market application was then developed; the application is an android application that will assist communal farmers in marketing their farm products as soon as they are available to avoid food wastage. The application performance and evaluation assessment indicated that the tool would maximize farm productivity and profitability and, facilitate concise and effective access to the market, as well as eliminate the need for an intermediary. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-02
- Authors: Fatumo, Dare Ebenezer
- Date: 2023-02
- Subjects: Food security , Agriculture , Agriculture -- Technology transfer
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27511 , vital:67421
- Description: The application of Information and Communication Technologies (ICT) in agriculture can augment farmers' production capabilities, this is a perception for all farmers worldwide, but there are some in communal areas who may not be as exposed to ICT tools as their commercial counterparts in urban areas, especially in developed communities. Food security in any society is a vital measure that should always be treated with high priority since humankind's existence is based on food availability. One major challenge with farmers in communal areas has been the marketing of their farm produce effectively to avoid wastage, get more value, and bridge the gap between themselves and urban commercial farmers. This challenge includes food wastage, untimely information, and market accessibility due to distance restraint. ICT can beused to bring a functional platform to assist this challenge. In this context, communal farmers have a challenge. The aim of this research was to design and develop an easy-to-use mobilebased e-marketing application for marketing farm products for communal farmers in Alice community, South Africa. Before design and development, review of challenges of farmers on the reception and communication of sensitive information pertaining to food security. Effective communication of farm produce baseline information on awareness and adaptation of mobile ICT technology of communal farmers was investigated. A mixed method was used through reviews of literature and as well distribution of questionnaires to get an understanding of the present state of communal farmers’ marketing problems. Furthermore, a prototyping methodology was used in the development of the mobile-based application for this research. The result of this research demonstrated the need for communal farmers to market their farm products at their convenience. An easy-to-use mobile-based e-market application was then developed; the application is an android application that will assist communal farmers in marketing their farm products as soon as they are available to avoid food wastage. The application performance and evaluation assessment indicated that the tool would maximize farm productivity and profitability and, facilitate concise and effective access to the market, as well as eliminate the need for an intermediary. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-02
A Comparative Analysis of Speaker and Headphone-Based Immersive Audio in VR and Gaming Applications:
- Authors: Marais, Kyle , Foss, Richard
- Date: 2023
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426705 , vital:72384 , https://ieeexplore.ieee.org/abstract/document/10289435
- Description: Precise and accurate audio spatialization is crucial for gaming and Virtual Reality (VR) applications, as it is an essential aspect of the immersion experienced by users. When the audio of a virtual environment is synchronized with its visual sources and localized accurately, users are more likely to feel deeply engaged and suspend their disbelief. Audio Middleware software is commonly used in cooperation with game engines to meet the audio requirements of virtual environments created by game developers. This research paper presents a comparative analysis of speaker-and headphone-based immersive audio systems within the context of VR. The research findings indicate that, despite the headphone-based system offering more accurate audio localization and a higher ‘perceived audio quality’, the speaker-based system resulted in a greater sense of ‘immersion.’.
- Full Text:
- Date Issued: 2023
A Comparative Analysis of Speaker and Headphone-Based Immersive Audio in VR and Gaming Applications:
- Authors: Marais, Kyle , Foss, Richard
- Date: 2023
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426705 , vital:72384 , https://ieeexplore.ieee.org/abstract/document/10289435
- Description: Precise and accurate audio spatialization is crucial for gaming and Virtual Reality (VR) applications, as it is an essential aspect of the immersion experienced by users. When the audio of a virtual environment is synchronized with its visual sources and localized accurately, users are more likely to feel deeply engaged and suspend their disbelief. Audio Middleware software is commonly used in cooperation with game engines to meet the audio requirements of virtual environments created by game developers. This research paper presents a comparative analysis of speaker-and headphone-based immersive audio systems within the context of VR. The research findings indicate that, despite the headphone-based system offering more accurate audio localization and a higher ‘perceived audio quality’, the speaker-based system resulted in a greater sense of ‘immersion.’.
- Full Text:
- Date Issued: 2023
Activated carbon-decorated polyacrylonitrile fibers and their porphyrin-immobilized composites for removal of methylene blue dye and Ciprofloxacin in water
- Oyim, James, Amuhaya, Edith, Nyokong, Tebello
- Authors: Oyim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:65077 , xlink:href="https://doi.org/10.1080/10601325.2023.2183868"
- Description: Photocatalyst adsorbents are an appealing group of materials for environmental applications. Herein, we study a new simple, inexpensive, yet very effective adsorbent photocatalyst based on porphyrin immobilized activated carbon-decorated polyacrylonitrile, InP(PAN/AC), for removal of methylene blue dye and Ciprofloxacin in water under Xe-lamp and sunlight irradiation (the latter for Ciprofloxacin only). Our results shed light on developing the most effective and sustainable adsorbent photocatalysts that can easily be industrialized due to the ease of preparation through electrospinning coupled with the readily available preparation materials. After five cycles, the InP(PAN/AC) maintained high methylene dye removal efficiency and structural integrity. Significantly, we propose the coordinated contribution of singlet oxygen and hydroxyl radical in the photodegradation process and highlight the importance of such an integrated system with adsorption and photodegradation capabilities for water treatment.
- Full Text:
- Date Issued: 2023
- Authors: Oyim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:65077 , xlink:href="https://doi.org/10.1080/10601325.2023.2183868"
- Description: Photocatalyst adsorbents are an appealing group of materials for environmental applications. Herein, we study a new simple, inexpensive, yet very effective adsorbent photocatalyst based on porphyrin immobilized activated carbon-decorated polyacrylonitrile, InP(PAN/AC), for removal of methylene blue dye and Ciprofloxacin in water under Xe-lamp and sunlight irradiation (the latter for Ciprofloxacin only). Our results shed light on developing the most effective and sustainable adsorbent photocatalysts that can easily be industrialized due to the ease of preparation through electrospinning coupled with the readily available preparation materials. After five cycles, the InP(PAN/AC) maintained high methylene dye removal efficiency and structural integrity. Significantly, we propose the coordinated contribution of singlet oxygen and hydroxyl radical in the photodegradation process and highlight the importance of such an integrated system with adsorption and photodegradation capabilities for water treatment.
- Full Text:
- Date Issued: 2023
Asymmetrical zinc phthalocyanine conjugated to various nanomaterials for applications in phototransformation of organic pollutants and photoinactivation of bacteria
- Mgidlana, Sithi, Openda, Yolande Ikala, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360344 , vital:65081 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.134850"
- Description: Zinc phthalocyanine (ZnPc) complexes are linked to metallic nanoparticles covalently via amide and ester bonds. The photocatalytic activity of the conjugates of ZnPc complexes with NiWO4, Ag2WO4, CoWO4 and Ag-Fe3O4 nanoparticles are evaluated for photodegradation of methylene blue, tetracycline, and dibenzothiophene. The photocatalytic efficiencies of the prepared phthalocyanine complexes increased in the presence of nanoparticles. This work also reports on the photodynamic antimicrobial chemotherapy activity of these materials against Staphylococcus aureus (S. aureus) bacteria. The results indicate that Ag2WO4 based nanoconjugates exhibit high antimicrobial activity with higher log reduction compared to NiWO4, CoWO4 and Ag-Fe3O4 based materials.
- Full Text:
- Date Issued: 2023
- Authors: Mgidlana, Sithi , Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360344 , vital:65081 , xlink:href="https://doi.org/10.1016/j.molstruc.2022.134850"
- Description: Zinc phthalocyanine (ZnPc) complexes are linked to metallic nanoparticles covalently via amide and ester bonds. The photocatalytic activity of the conjugates of ZnPc complexes with NiWO4, Ag2WO4, CoWO4 and Ag-Fe3O4 nanoparticles are evaluated for photodegradation of methylene blue, tetracycline, and dibenzothiophene. The photocatalytic efficiencies of the prepared phthalocyanine complexes increased in the presence of nanoparticles. This work also reports on the photodynamic antimicrobial chemotherapy activity of these materials against Staphylococcus aureus (S. aureus) bacteria. The results indicate that Ag2WO4 based nanoconjugates exhibit high antimicrobial activity with higher log reduction compared to NiWO4, CoWO4 and Ag-Fe3O4 based materials.
- Full Text:
- Date Issued: 2023
Best practices in the use and exchange of microorganism biological control genetic resources
- Mason, Peter G, Hill, Martin P, Smith, David, Silvestri, Luciano C, Weyl, Philip S R, Brodeur, Jacques, Vitorino, Marcello Diniz
- Authors: Mason, Peter G , Hill, Martin P , Smith, David , Silvestri, Luciano C , Weyl, Philip S R , Brodeur, Jacques , Vitorino, Marcello Diniz
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417927 , vital:71495 , xlink:href="https://doi.org/10.1007/s10526-023-10197-3"
- Description: The Nagoya Protocol actions the third objective of the Convention on Biological Diversity and provides a framework to effectively implement the fair and equitable sharing of benefits arising out of the use of genetic resources. This includes microorganisms used as biological control agents. Thus biological control practitioners must comply with access and benefit-sharing regulations that are implemented by countries providing microbial biological control agents. A review of best practices and guidance for the use and exchange of microorganisms used for biological control has been prepared by the IOBC Global Commission on Biological Control and Access and Benefit-Sharing to demonstrate commitment to comply with access and benefit-sharing requirements, and to reassure the international community that biological control is a very successful and environmentally safe pest management strategy that uses biological resources responsibly and sustainably. We propose that best practices include the following elements: collaboration to facilitate information exchange about the availability of microbial biological control agents and where they may be sourced; freely sharing available knowledge in databases about successes and failures; collaborative research with provider countries to develop capacity; and production technology transfer to provide economic opportunities. We recommend the use of model concept agreements for accessing microorganisms for scientific research and non-commercial release into nature where access and benefit-sharing regulations exist and where regulations are not restrictive or do not exist. We also recommend a model agreement for deposition of microbial biological control agents into culture collections.
- Full Text:
- Date Issued: 2023
- Authors: Mason, Peter G , Hill, Martin P , Smith, David , Silvestri, Luciano C , Weyl, Philip S R , Brodeur, Jacques , Vitorino, Marcello Diniz
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417927 , vital:71495 , xlink:href="https://doi.org/10.1007/s10526-023-10197-3"
- Description: The Nagoya Protocol actions the third objective of the Convention on Biological Diversity and provides a framework to effectively implement the fair and equitable sharing of benefits arising out of the use of genetic resources. This includes microorganisms used as biological control agents. Thus biological control practitioners must comply with access and benefit-sharing regulations that are implemented by countries providing microbial biological control agents. A review of best practices and guidance for the use and exchange of microorganisms used for biological control has been prepared by the IOBC Global Commission on Biological Control and Access and Benefit-Sharing to demonstrate commitment to comply with access and benefit-sharing requirements, and to reassure the international community that biological control is a very successful and environmentally safe pest management strategy that uses biological resources responsibly and sustainably. We propose that best practices include the following elements: collaboration to facilitate information exchange about the availability of microbial biological control agents and where they may be sourced; freely sharing available knowledge in databases about successes and failures; collaborative research with provider countries to develop capacity; and production technology transfer to provide economic opportunities. We recommend the use of model concept agreements for accessing microorganisms for scientific research and non-commercial release into nature where access and benefit-sharing regulations exist and where regulations are not restrictive or do not exist. We also recommend a model agreement for deposition of microbial biological control agents into culture collections.
- Full Text:
- Date Issued: 2023
Co phthalocyanine mediated electrochemical detection of the HER2 in the presence of Au and CeO2 nanoparticles and graphene quantum dots
- Centane, Sixolile, Nyokong, Tebello
- Authors: Centane, Sixolile , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360372 , vital:65083 , xlink:href="https://doi.org/10.1016/j.bioelechem.2022.108301"
- Description: In this work, cobalt tetra phenoxy acetic acid phthalocyanine (CoTAPc) is investigated as an electron mediator, immobilization platform for an HB5 aptamer and to enhance the electrochemical signal for the detection of human epidermal growth factor receptor 2 (HER2). Furthermore, the CoTAPc was combined individually with sulphur/nitrogen doped graphene quantum dots (SNGQDs), gold nanoparticles (AuNPs) and cerium oxide nanoparticles (CeO2NPs), on a glassy carbon electrode (GCE) via sequential adsorption. The CoTAPc and SNGQDs were also π-π stacked, used for electrode modification similarly to the rest of the other surfaces and applied towards the electrochemical detection of HER2. The designed sensors were characterized using electrochemical impedance spectroscopy (EIS). The designed aptasensors showed detection limits as low as 6.0 pg/mL. The real life applicability of the designed aptasensors was tested in human serum samples. The aptasensors showed great storage stability, sensitivity and specificity towards HER2, implying great potential for applications in early diagnosis of breast cancer.
- Full Text:
- Date Issued: 2023
- Authors: Centane, Sixolile , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360372 , vital:65083 , xlink:href="https://doi.org/10.1016/j.bioelechem.2022.108301"
- Description: In this work, cobalt tetra phenoxy acetic acid phthalocyanine (CoTAPc) is investigated as an electron mediator, immobilization platform for an HB5 aptamer and to enhance the electrochemical signal for the detection of human epidermal growth factor receptor 2 (HER2). Furthermore, the CoTAPc was combined individually with sulphur/nitrogen doped graphene quantum dots (SNGQDs), gold nanoparticles (AuNPs) and cerium oxide nanoparticles (CeO2NPs), on a glassy carbon electrode (GCE) via sequential adsorption. The CoTAPc and SNGQDs were also π-π stacked, used for electrode modification similarly to the rest of the other surfaces and applied towards the electrochemical detection of HER2. The designed sensors were characterized using electrochemical impedance spectroscopy (EIS). The designed aptasensors showed detection limits as low as 6.0 pg/mL. The real life applicability of the designed aptasensors was tested in human serum samples. The aptasensors showed great storage stability, sensitivity and specificity towards HER2, implying great potential for applications in early diagnosis of breast cancer.
- Full Text:
- Date Issued: 2023
Combination of photodynamic antimicrobial chemotherapy and ciprofloxacin to combat S. aureus and E. coli resistant biofilms
- Openda, Yolande Ikala, Nyokong, Tebello
- Authors: Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360384 , vital:65084 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103142"
- Description: Photodynamic antimicrobial chemotherapy (PACT) coupled with an antibiotic, ciprofloxacin (CIP), was investigated using two indium metallated cationic photosensitizers, a porphyrin (1) and a phthalocyanine (2). Applying PACT followed by the antibiotic treatment led to a remarkable reduction in the biofilm cell survival of two antibiotic-resistant bacterial strains, S. aureus (Gram-positive) and E. coli (Gram-nenative). Treating both bacteria strains with PACT alone showed no significant activity at 32 µM with 15 min irradiation, while CIP alone exhibited a minimum biofilm inhibition concentration (MBIC) at 4 and 8 µg/mL on S. aureus and E. coli, respectively following 24 h incubation. The combined treatment resulted in the complete eradication of the matured biofilms with high log10 reduction values of 7.05 and 7.20 on S. aureus and E. coli, respectively, at low concentrations. It was found that 15 min PACT irradiation of 8 µM of complexes (1 and 2) combined with 2 µg/mL of CIP have a 100% reduction of the resistant S. aureus biofilms. Whereas the total killing of E. coli was obtained when combining 8 µM of complex 1 and 16 µM of complex 2 both combined with 4 µg/mL of CIP.
- Full Text:
- Date Issued: 2023
- Authors: Openda, Yolande Ikala , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360384 , vital:65084 , xlink:href="https://doi.org/10.1016/j.pdpdt.2022.103142"
- Description: Photodynamic antimicrobial chemotherapy (PACT) coupled with an antibiotic, ciprofloxacin (CIP), was investigated using two indium metallated cationic photosensitizers, a porphyrin (1) and a phthalocyanine (2). Applying PACT followed by the antibiotic treatment led to a remarkable reduction in the biofilm cell survival of two antibiotic-resistant bacterial strains, S. aureus (Gram-positive) and E. coli (Gram-nenative). Treating both bacteria strains with PACT alone showed no significant activity at 32 µM with 15 min irradiation, while CIP alone exhibited a minimum biofilm inhibition concentration (MBIC) at 4 and 8 µg/mL on S. aureus and E. coli, respectively following 24 h incubation. The combined treatment resulted in the complete eradication of the matured biofilms with high log10 reduction values of 7.05 and 7.20 on S. aureus and E. coli, respectively, at low concentrations. It was found that 15 min PACT irradiation of 8 µM of complexes (1 and 2) combined with 2 µg/mL of CIP have a 100% reduction of the resistant S. aureus biofilms. Whereas the total killing of E. coli was obtained when combining 8 µM of complex 1 and 16 µM of complex 2 both combined with 4 µg/mL of CIP.
- Full Text:
- Date Issued: 2023
Contrasting effects of climate change on the invasion risk and biocontrol potential of the invasive Iris pseudacorus L. between Northern and Southern Hemisphere
- Minuti, Gianmarco, Coetzee, Julie A, Stiers, Iris
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Stiers, Iris
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423329 , vital:72048 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105290"
- Description: Iris pseudacorus is both a prized ornamental and an invasive aquatic plant that tends to grow dense monospecific stands, displacing the local vegetation and altering the hydrology of freshwater ecosystems. Originally from Europe, this species has historically invaded North America, China and Japan, and more recently spread through Argentina, South Africa and Australasia, where it is now a target for biological control. Field surveys within its native range have led to the selection of three candidate biocontrol agents. Prioritizing the best candidates for different regions constitutes a critical step, which could save significant time and resources before further cost-intensive experimental studies are conducted. Climate change is seldom taken into consideration in the prioritization process. In this regard, climatic suitability can be used to model the potential distributions of weeds and their candidate agents, both in space and time, thus allowing to identify areas at risk of invasion and predict where agents will be able to establish long-term. Accordingly, the objectives of this work were (i) to predict I. pseudacorus invasions and range shifts in the context of climate change; (ii) to identify wetland areas most at risk of invasion under present and future climatic conditions; and (iii) to prioritize the best suite of candidate biocontrol agents for different invaded ranges, worldwide. To do so, we modelled the present and future (2040–2060) climatic suitability of I. pseudacorus and its candidate agents using the software MaxEnt. Our results highlight a clear distinction between predictions for the Northern and Southern Hemispheres. In North America and eastern Asia, the area climatically suitable for I. pseudacorus is expected to increase and shift northwards. As for its biocontrol agents, very low suitability is predicted across these regions, further decreasing under future climatic conditions. On the other hand, climatically suitable areas for the plant in South America, southern Africa and Australasia are predicted, on average, to reduce in response to climate change. A decrease in climatic suitability is also expected for its candidate biocontrol agents which, however, would still maintain a significant range overlap with their host. These results can be used to prioritize areas most at risk of invasion and identify which combination of candidates could potentially provide the best level of control across different invaded ranges.
- Full Text:
- Date Issued: 2023
- Authors: Minuti, Gianmarco , Coetzee, Julie A , Stiers, Iris
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423329 , vital:72048 , xlink:href="https://doi.org/10.1016/j.biocontrol.2023.105290"
- Description: Iris pseudacorus is both a prized ornamental and an invasive aquatic plant that tends to grow dense monospecific stands, displacing the local vegetation and altering the hydrology of freshwater ecosystems. Originally from Europe, this species has historically invaded North America, China and Japan, and more recently spread through Argentina, South Africa and Australasia, where it is now a target for biological control. Field surveys within its native range have led to the selection of three candidate biocontrol agents. Prioritizing the best candidates for different regions constitutes a critical step, which could save significant time and resources before further cost-intensive experimental studies are conducted. Climate change is seldom taken into consideration in the prioritization process. In this regard, climatic suitability can be used to model the potential distributions of weeds and their candidate agents, both in space and time, thus allowing to identify areas at risk of invasion and predict where agents will be able to establish long-term. Accordingly, the objectives of this work were (i) to predict I. pseudacorus invasions and range shifts in the context of climate change; (ii) to identify wetland areas most at risk of invasion under present and future climatic conditions; and (iii) to prioritize the best suite of candidate biocontrol agents for different invaded ranges, worldwide. To do so, we modelled the present and future (2040–2060) climatic suitability of I. pseudacorus and its candidate agents using the software MaxEnt. Our results highlight a clear distinction between predictions for the Northern and Southern Hemispheres. In North America and eastern Asia, the area climatically suitable for I. pseudacorus is expected to increase and shift northwards. As for its biocontrol agents, very low suitability is predicted across these regions, further decreasing under future climatic conditions. On the other hand, climatically suitable areas for the plant in South America, southern Africa and Australasia are predicted, on average, to reduce in response to climate change. A decrease in climatic suitability is also expected for its candidate biocontrol agents which, however, would still maintain a significant range overlap with their host. These results can be used to prioritize areas most at risk of invasion and identify which combination of candidates could potentially provide the best level of control across different invaded ranges.
- Full Text:
- Date Issued: 2023
Declines in Livestock Numbers Accompany Cropping Deagrarianisation Processes in the Eastern Cape, South Africa
- Shackleton, Charlie M, Ntshudu, Monde
- Authors: Shackleton, Charlie M , Ntshudu, Monde
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402248 , vital:69834 , xlink:href="https://doi.org/10.3390/land12091735"
- Description: Deagrarianisation amongst smallholder farmers is a growing phenomenon globally, driven by a complex array of context-specific and higher-scale factors. Most research has focused on declines in arable cropping, with relatively little regard to the deagrarianisation dynamics associated with livestock ownership, yet the two are often linked through the need for draught power for ploughing. Here, we report on a survey of 293 rural households in 10 rural villages in the Eastern Cape province, South Africa, where we ascertained whether ownership of cattle, goats, sheep and pigs had changed over the previous 15 years and what were the underlying reasons for any changes at both village- and household-scale. The majority felt that there had been a decline in the number of households keeping livestock and the number of animals in the village. Additionally, a clear majority of owners for each type of livestock stated that their households currently have fewer animals than 15 years ago. The main reasons for declines were that their animals had died due to drought or disease, theft, or they had sold them because of financial needs. There was a positive association between the keeping of cattle and field cultivation. Despite these general declines, two-thirds of households currently without livestock wished that they had some, primarily for use in cultural ceremonies/rituals or for income. This study shows the deagrarianisation processes in the region also apply to the livestock sector despite the significance of livestock in the local Xhosa culture. This study highlights the multifaceted nature of deagrarianisation in communal tenure systems.
- Full Text:
- Date Issued: 2023
- Authors: Shackleton, Charlie M , Ntshudu, Monde
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402248 , vital:69834 , xlink:href="https://doi.org/10.3390/land12091735"
- Description: Deagrarianisation amongst smallholder farmers is a growing phenomenon globally, driven by a complex array of context-specific and higher-scale factors. Most research has focused on declines in arable cropping, with relatively little regard to the deagrarianisation dynamics associated with livestock ownership, yet the two are often linked through the need for draught power for ploughing. Here, we report on a survey of 293 rural households in 10 rural villages in the Eastern Cape province, South Africa, where we ascertained whether ownership of cattle, goats, sheep and pigs had changed over the previous 15 years and what were the underlying reasons for any changes at both village- and household-scale. The majority felt that there had been a decline in the number of households keeping livestock and the number of animals in the village. Additionally, a clear majority of owners for each type of livestock stated that their households currently have fewer animals than 15 years ago. The main reasons for declines were that their animals had died due to drought or disease, theft, or they had sold them because of financial needs. There was a positive association between the keeping of cattle and field cultivation. Despite these general declines, two-thirds of households currently without livestock wished that they had some, primarily for use in cultural ceremonies/rituals or for income. This study shows the deagrarianisation processes in the region also apply to the livestock sector despite the significance of livestock in the local Xhosa culture. This study highlights the multifaceted nature of deagrarianisation in communal tenure systems.
- Full Text:
- Date Issued: 2023
Development of a translation device for axiological-semantic density in political news articles: Wording and charging
- Siebörger, Ian, Adendorff, Ralph D
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385311 , vital:68006 , xlink:href="https://doi.org/10.1515/text-2020-0156"
- Description: The concept of axiological-semantic density from Legitimation Code Theory (LCT) is extremely helpful in analysing political knowledge-building, as it describes the strength of relations between various people, political stances and moral judgements, enabling these to be positioned in relation to each other. We present a multi-level translation device designed to identify strengths of axiological-semantic density in political news articles from the Daily Sun, South Africa’s most popular tabloid newspaper. This translation device was devised through analysis of selected texts from a corpus of 516 articles published between January and June 2015. It was developed through a collaborative process involving the first author and a team of student research assistants. The final translation device has five tools, of which two, the wording and charging tools, are described in this article, and then illustrated using an example analysis of a Daily Sun political news article. Both tools reveal insights into South African political discourses and ways in which axiological-semantic density can be enacted in future research. Making axiological-semantic density visible using such a translation device also has practical applications in assisting readers to understand the ways in which publications such as the Daily Sun position political parties, enabling them to engage more constructively in discussions on the country’s future.
- Full Text:
- Date Issued: 2023
- Authors: Siebörger, Ian , Adendorff, Ralph D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/385311 , vital:68006 , xlink:href="https://doi.org/10.1515/text-2020-0156"
- Description: The concept of axiological-semantic density from Legitimation Code Theory (LCT) is extremely helpful in analysing political knowledge-building, as it describes the strength of relations between various people, political stances and moral judgements, enabling these to be positioned in relation to each other. We present a multi-level translation device designed to identify strengths of axiological-semantic density in political news articles from the Daily Sun, South Africa’s most popular tabloid newspaper. This translation device was devised through analysis of selected texts from a corpus of 516 articles published between January and June 2015. It was developed through a collaborative process involving the first author and a team of student research assistants. The final translation device has five tools, of which two, the wording and charging tools, are described in this article, and then illustrated using an example analysis of a Daily Sun political news article. Both tools reveal insights into South African political discourses and ways in which axiological-semantic density can be enacted in future research. Making axiological-semantic density visible using such a translation device also has practical applications in assisting readers to understand the ways in which publications such as the Daily Sun position political parties, enabling them to engage more constructively in discussions on the country’s future.
- Full Text:
- Date Issued: 2023
Distribution and impact of the native South African wasp, Megastigmus transvaalensis (Hussey, 1956)(Hymenoptera: Torymidae) on the invasive Schinus terebinthifolia Raddi (Anacardiaceae) in South Africa
- Mangenlele, Nwabisa L, Martin, Grant D
- Authors: Mangenlele, Nwabisa L , Martin, Grant D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416841 , vital:71390 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a12"
- Description: Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian pepper tree) is a tree native to subtropical South America that was introduced into South Africa as an ornamental plant. Globally, it is regarded as one of the world’s worst invasive trees. In South Africa the tree has acquired a native seed-feeding wasp, Megastigmus transvaalensis (Hussey, 1956) (Hymenoptera: Torymidae). The wasp’s native hosts are from the Searsia F.A. Barkley genus (Anacardiaceae), but it has expanded its host range to form a new association with both S. terebinthifolia and its close relative Schinus molle L. (Anacardiaceae). In order to quantify the seed predation by M. transvaalensis on S. terebinthifolia seeds, tree populations were surveyed across the Eastern Cape and KwaZulu-Natal provinces. The wasp was present at 99% of the S. terebinthifolia populations with an average of 22% of the seeds being destroyed. In the Eastern Cape province, the highest seed damage occurred at the start of the winter months, when about 35% of seeds were damaged. This fell to less than 12% in spring and summer when the plants were flowering. Megastigmus transvaalensis was found at nearly all the S. terebinthifolia populations in South Africa, but due to the limited number of predated seeds it is unlikely to reduce population sizes or curb the spread of the invasive alien tree in South Africa.
- Full Text:
- Date Issued: 2023
- Authors: Mangenlele, Nwabisa L , Martin, Grant D
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416841 , vital:71390 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a12"
- Description: Schinus terebinthifolia Raddi (Anacardiaceae) (Brazilian pepper tree) is a tree native to subtropical South America that was introduced into South Africa as an ornamental plant. Globally, it is regarded as one of the world’s worst invasive trees. In South Africa the tree has acquired a native seed-feeding wasp, Megastigmus transvaalensis (Hussey, 1956) (Hymenoptera: Torymidae). The wasp’s native hosts are from the Searsia F.A. Barkley genus (Anacardiaceae), but it has expanded its host range to form a new association with both S. terebinthifolia and its close relative Schinus molle L. (Anacardiaceae). In order to quantify the seed predation by M. transvaalensis on S. terebinthifolia seeds, tree populations were surveyed across the Eastern Cape and KwaZulu-Natal provinces. The wasp was present at 99% of the S. terebinthifolia populations with an average of 22% of the seeds being destroyed. In the Eastern Cape province, the highest seed damage occurred at the start of the winter months, when about 35% of seeds were damaged. This fell to less than 12% in spring and summer when the plants were flowering. Megastigmus transvaalensis was found at nearly all the S. terebinthifolia populations in South Africa, but due to the limited number of predated seeds it is unlikely to reduce population sizes or curb the spread of the invasive alien tree in South Africa.
- Full Text:
- Date Issued: 2023
Diverse values of nature for sustainability
- Pascual, Unai, Balvanera, Patricia, Anderson, Christopher B, Chaplin-Kramer, Rebecca, Christie, Michael, González-Jiménez, David, Martin, Adrian, Raymond, Christopher M, Termansen, Mette, Vatn, Arild, Athayde, Simone, Baptiste, Brigitte, Barton, Davind N, Jacobs, Sander, Kelemen, Eszter, Kumar, Ritesh, Lazos, Elena, Mwampamba, Tuyeni H, Nakangu, Barbara, O’Farrell, Patrick, Subramanian, Suneetha M, van Noordwijk, Meine, Ahn, SoEun, Amaruzaman, Sacha, Amin, Ariane M, Arias-Arévalo, Paola, Arroyo-Robles, Gabriela, Cantú-Fernández, Mariana, Castro, Antonio J, Contreras, Victoria, de Vos, Alta, Dendoncker, Nicolas, Engel, Stefanie, Eser, Uta, Faith, Daniel P, Filyushkina, Anna, Ghazi, Houda, Gómez-Baggethun, Erik, Gould, Rachelle K, Guibrunet, Louise, Gundimeda, Haripriya, Hahn, Thomas, Harmáčková, Zuzana V, Hernández-Blanco, Marcello, Horcea-Milcu, Andra-loana, Huambachano, Mariaelena, Wicher, Natalia L H, Aydın, Cem I, Islar, Mine, Koessler, Ann-Kathrin, Kenter, Jasper O, Kosmus, Marina, Lee, Heera, Leimona, Beria, Lele, Sharachchandra, Lenzi, Dominic, Lliso, Bosco, Mannetii, Lelani M, Merçon, Juliana, Monroy-Sais, Ana S, Mukherjee, Nibedita, Muraca, Barbara, Muradian, Roldan, Murali, Ranjini, Nelson, Sara H, Nemogá-Soto, Gabriel R, Ngouhouo-Poufoun, Jonas, Niamir, Aidin, Nuesiri, Emmanuel, Nyumba, Tobias O, Özkaynak, Begüm, Palomo, Ignacio, Pandit, Ram, Pawłowska-Mainville, Agnieszka, Porter-Bolland, Luciano, Quaas, Martin, Rode, Julian, Rozzi, Ricardo, Sachdeva, Sonya, Aibek, Samakov, Schaafsma, Marije, Sitas, Nadia, Ungar, Paula, Yiu, Evonne, Yoshida, Yuki, Zent, Eglee
- Authors: Pascual, Unai , Balvanera, Patricia , Anderson, Christopher B , Chaplin-Kramer, Rebecca , Christie, Michael , González-Jiménez, David , Martin, Adrian , Raymond, Christopher M , Termansen, Mette , Vatn, Arild , Athayde, Simone , Baptiste, Brigitte , Barton, Davind N , Jacobs, Sander , Kelemen, Eszter , Kumar, Ritesh , Lazos, Elena , Mwampamba, Tuyeni H , Nakangu, Barbara , O’Farrell, Patrick , Subramanian, Suneetha M , van Noordwijk, Meine , Ahn, SoEun , Amaruzaman, Sacha , Amin, Ariane M , Arias-Arévalo, Paola , Arroyo-Robles, Gabriela , Cantú-Fernández, Mariana , Castro, Antonio J , Contreras, Victoria , de Vos, Alta , Dendoncker, Nicolas , Engel, Stefanie , Eser, Uta , Faith, Daniel P , Filyushkina, Anna , Ghazi, Houda , Gómez-Baggethun, Erik , Gould, Rachelle K , Guibrunet, Louise , Gundimeda, Haripriya , Hahn, Thomas , Harmáčková, Zuzana V , Hernández-Blanco, Marcello , Horcea-Milcu, Andra-loana , Huambachano, Mariaelena , Wicher, Natalia L H , Aydın, Cem I , Islar, Mine , Koessler, Ann-Kathrin , Kenter, Jasper O , Kosmus, Marina , Lee, Heera , Leimona, Beria , Lele, Sharachchandra , Lenzi, Dominic , Lliso, Bosco , Mannetii, Lelani M , Merçon, Juliana , Monroy-Sais, Ana S , Mukherjee, Nibedita , Muraca, Barbara , Muradian, Roldan , Murali, Ranjini , Nelson, Sara H , Nemogá-Soto, Gabriel R , Ngouhouo-Poufoun, Jonas , Niamir, Aidin , Nuesiri, Emmanuel , Nyumba, Tobias O , Özkaynak, Begüm , Palomo, Ignacio , Pandit, Ram , Pawłowska-Mainville, Agnieszka , Porter-Bolland, Luciano , Quaas, Martin , Rode, Julian , Rozzi, Ricardo , Sachdeva, Sonya , Aibek, Samakov , Schaafsma, Marije , Sitas, Nadia , Ungar, Paula , Yiu, Evonne , Yoshida, Yuki , Zent, Eglee
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415612 , vital:71270 , xlink:href="https://doi.org/10.1038/s41586-023-06406-9"
- Description: Twenty-five years since foundational publications on valuing ecosystem services for human well-being, addressing the global biodiversity crisis still implies confronting barriers to incorporating nature’s diverse values into decision-making. These barriers include powerful interests supported by current norms and legal rules such as property rights, which determine whose values and which values of nature are acted on. A better understanding of how and why nature is (under)valued is more urgent than ever. Notwithstanding agreements to incorporate nature’s values into actions, including the Kunming-Montreal Global Biodiversity Framework (GBF) and the UN Sustainable Development Goals, predominant environmental and development policies still prioritize a subset of values, particularly those linked to markets, and ignore other ways people relate to and benefit from nature. Arguably, a ‘values crisis’ underpins the intertwined crises of biodiversity loss and climate change, pandemic emergence and socio-environmental injustices. On the basis of more than 50,000 scientifc publications, policy documents and Indigenous and local knowledge sources, the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) assessed knowledge on nature’s diverse values and valuation methods to gain insights into their role in policymaking and fuller integration into decisions. Applying this evidence, combinations of values-centred approaches are proposed to improve valuation and address barriers to uptake, ultimately leveraging transformative changes towards more just (that is, fair treatment of people and nature, including inter- and intragenerational equity) and sustainable futures.
- Full Text:
- Date Issued: 2023
- Authors: Pascual, Unai , Balvanera, Patricia , Anderson, Christopher B , Chaplin-Kramer, Rebecca , Christie, Michael , González-Jiménez, David , Martin, Adrian , Raymond, Christopher M , Termansen, Mette , Vatn, Arild , Athayde, Simone , Baptiste, Brigitte , Barton, Davind N , Jacobs, Sander , Kelemen, Eszter , Kumar, Ritesh , Lazos, Elena , Mwampamba, Tuyeni H , Nakangu, Barbara , O’Farrell, Patrick , Subramanian, Suneetha M , van Noordwijk, Meine , Ahn, SoEun , Amaruzaman, Sacha , Amin, Ariane M , Arias-Arévalo, Paola , Arroyo-Robles, Gabriela , Cantú-Fernández, Mariana , Castro, Antonio J , Contreras, Victoria , de Vos, Alta , Dendoncker, Nicolas , Engel, Stefanie , Eser, Uta , Faith, Daniel P , Filyushkina, Anna , Ghazi, Houda , Gómez-Baggethun, Erik , Gould, Rachelle K , Guibrunet, Louise , Gundimeda, Haripriya , Hahn, Thomas , Harmáčková, Zuzana V , Hernández-Blanco, Marcello , Horcea-Milcu, Andra-loana , Huambachano, Mariaelena , Wicher, Natalia L H , Aydın, Cem I , Islar, Mine , Koessler, Ann-Kathrin , Kenter, Jasper O , Kosmus, Marina , Lee, Heera , Leimona, Beria , Lele, Sharachchandra , Lenzi, Dominic , Lliso, Bosco , Mannetii, Lelani M , Merçon, Juliana , Monroy-Sais, Ana S , Mukherjee, Nibedita , Muraca, Barbara , Muradian, Roldan , Murali, Ranjini , Nelson, Sara H , Nemogá-Soto, Gabriel R , Ngouhouo-Poufoun, Jonas , Niamir, Aidin , Nuesiri, Emmanuel , Nyumba, Tobias O , Özkaynak, Begüm , Palomo, Ignacio , Pandit, Ram , Pawłowska-Mainville, Agnieszka , Porter-Bolland, Luciano , Quaas, Martin , Rode, Julian , Rozzi, Ricardo , Sachdeva, Sonya , Aibek, Samakov , Schaafsma, Marije , Sitas, Nadia , Ungar, Paula , Yiu, Evonne , Yoshida, Yuki , Zent, Eglee
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415612 , vital:71270 , xlink:href="https://doi.org/10.1038/s41586-023-06406-9"
- Description: Twenty-five years since foundational publications on valuing ecosystem services for human well-being, addressing the global biodiversity crisis still implies confronting barriers to incorporating nature’s diverse values into decision-making. These barriers include powerful interests supported by current norms and legal rules such as property rights, which determine whose values and which values of nature are acted on. A better understanding of how and why nature is (under)valued is more urgent than ever. Notwithstanding agreements to incorporate nature’s values into actions, including the Kunming-Montreal Global Biodiversity Framework (GBF) and the UN Sustainable Development Goals, predominant environmental and development policies still prioritize a subset of values, particularly those linked to markets, and ignore other ways people relate to and benefit from nature. Arguably, a ‘values crisis’ underpins the intertwined crises of biodiversity loss and climate change, pandemic emergence and socio-environmental injustices. On the basis of more than 50,000 scientifc publications, policy documents and Indigenous and local knowledge sources, the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) assessed knowledge on nature’s diverse values and valuation methods to gain insights into their role in policymaking and fuller integration into decisions. Applying this evidence, combinations of values-centred approaches are proposed to improve valuation and address barriers to uptake, ultimately leveraging transformative changes towards more just (that is, fair treatment of people and nature, including inter- and intragenerational equity) and sustainable futures.
- Full Text:
- Date Issued: 2023
Do thermal requirements of Dichrorampha odorata, a shoot-boring moth for the biological control of Chromolaena odorata, explain its failure to establish in South Africa?
- Nqayi, Slindile B, Zachariades, Costas, Coetzee, Julie A, Hill, Martin P, Chidwanyika, Frank, Uyi, Osariyekemwen O, McConnachie, Andrew J
- Authors: Nqayi, Slindile B , Zachariades, Costas , Coetzee, Julie A , Hill, Martin P , Chidwanyika, Frank , Uyi, Osariyekemwen O , McConnachie, Andrew J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416851 , vital:71391 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a14"
- Description: Chromolaena odorata (L.) RM King and H Rob. (Asteraceae) has been subject to a biological control programme in South Africa for over three decades. A shoot-tip boring moth, Dichrorampha odorata Brown and Zachariades (Lepidoptera: Tortricidae), originating from Jamaica, was released as a biological control agent in 2013 but despite the release of substantial numbers of the insect, it has not established a permanent field population. Because climate incompatibility is a major constraint for classical biological control of invasive plants, and based on the differences in climate between Jamaica and South Africa and field observations at release sites, aspects of the thermal physiology of D. odorata were investigated to elucidate reasons for its failure to establish. Developmental time decreased with increasing temperatures ranging from 20 °C to 30 °C, with incomplete development for immature stages at 18 °C and 32 °C. The developmental threshold, t, was calculated as 8.45 °C with 872.4 degree-days required to complete development (K). A maximum of 6.5 generations per year was projected for D. odorata in South Africa, with the heavily infested eastern region of the country being the most eco-climatically suitable for establishment. The lower lethal temperature (LLT50) of larvae and adults was –4.5 and 1.8 °C, respectively. The upper lethal temperature (ULT50) for larvae was 39.6 °C whilst that of adults was 41.0 °C. Larvae thus had better cold tolerance compared to adults whereas adults had better heat tolerance compared to larvae. The critical thermal (CT) limits for adults were 3.4 ± 0.07 to 43.7 ± 0.12 °C. Acclimation at 20 °C for 7 days resulted in increased cold and heat tolerance with a CTmin and CTmax of 1.9 ± 0.06 and 44.4 ± 0.07 °C respectively, compared to the relative control, acclimated at 25 °C. Acclimation at 30 °C improved neither cold (CTmin: 5.9 ± 0.08 °C) nor heat tolerance (CTmax: 42.9 ± 0.10 °C). These results suggest that thermal requirements fall within field temperatures and are thus not the main constraining factor leading to poor establishment of D. odorata in South Africa.
- Full Text:
- Date Issued: 2023
- Authors: Nqayi, Slindile B , Zachariades, Costas , Coetzee, Julie A , Hill, Martin P , Chidwanyika, Frank , Uyi, Osariyekemwen O , McConnachie, Andrew J
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416851 , vital:71391 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v31_n1_a14"
- Description: Chromolaena odorata (L.) RM King and H Rob. (Asteraceae) has been subject to a biological control programme in South Africa for over three decades. A shoot-tip boring moth, Dichrorampha odorata Brown and Zachariades (Lepidoptera: Tortricidae), originating from Jamaica, was released as a biological control agent in 2013 but despite the release of substantial numbers of the insect, it has not established a permanent field population. Because climate incompatibility is a major constraint for classical biological control of invasive plants, and based on the differences in climate between Jamaica and South Africa and field observations at release sites, aspects of the thermal physiology of D. odorata were investigated to elucidate reasons for its failure to establish. Developmental time decreased with increasing temperatures ranging from 20 °C to 30 °C, with incomplete development for immature stages at 18 °C and 32 °C. The developmental threshold, t, was calculated as 8.45 °C with 872.4 degree-days required to complete development (K). A maximum of 6.5 generations per year was projected for D. odorata in South Africa, with the heavily infested eastern region of the country being the most eco-climatically suitable for establishment. The lower lethal temperature (LLT50) of larvae and adults was –4.5 and 1.8 °C, respectively. The upper lethal temperature (ULT50) for larvae was 39.6 °C whilst that of adults was 41.0 °C. Larvae thus had better cold tolerance compared to adults whereas adults had better heat tolerance compared to larvae. The critical thermal (CT) limits for adults were 3.4 ± 0.07 to 43.7 ± 0.12 °C. Acclimation at 20 °C for 7 days resulted in increased cold and heat tolerance with a CTmin and CTmax of 1.9 ± 0.06 and 44.4 ± 0.07 °C respectively, compared to the relative control, acclimated at 25 °C. Acclimation at 30 °C improved neither cold (CTmin: 5.9 ± 0.08 °C) nor heat tolerance (CTmax: 42.9 ± 0.10 °C). These results suggest that thermal requirements fall within field temperatures and are thus not the main constraining factor leading to poor establishment of D. odorata in South Africa.
- Full Text:
- Date Issued: 2023
Dual action of asymmetrical zinc (II) phthalocyanines conjugated to silver tungstate nanoparticles towards photodegradation of tetracycline and inactivation of Staphylococcus aureus bacteria
- Mgidlana, Sithi, Sen, Pinar, Nyokong, Tebello
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360400 , vital:65085 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114444"
- Description: Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1–3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photodegradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.
- Full Text:
- Date Issued: 2023
- Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360400 , vital:65085 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114444"
- Description: Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1–3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photodegradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.
- Full Text:
- Date Issued: 2023
Electrocatalytic Behavior of Manganese and Cobalt Porphyrins Attached to Graphene Quantum Dots: Applied in the Oxidation of Hydrazine
- Jokazi, Mbulelo, Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Jokazi, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360411 , vital:65086 , xlink:href="https://doi.org/10.1002/elan.202200222"
- Description: Manganese and cobalt metalated 5, 10, 15-tris(aminophenyl)-20-(4-carboxyphenyl) porphyrins (ClMnTA3CPP and CoTA3CPP) were synthesized and attached to graphene quantum dots (GQDs) via π-π interaction and electrostatic interaction. The electrochemical oxidation of hydrazine was performed via cyclic voltammetry and chronoamperometry. The CoTA3CPP showed good electrocatalytic activity towards the oxidation of hydrazine in terms of catalytic rate constants and limits of detection (LoD). ClMnTA3CPP showed lower overpotential 0.60 V. The introduction of GQDs improved the electrocatalytic ability when combined with CoTA3CPP and ClMnTA3CPP with the lowest LoD (0.0025 mM CoTA3CPP–GQDs) followed by ClMnTA3CPP–GQDs with 0.0033 mM.
- Full Text:
- Date Issued: 2023
- Authors: Jokazi, Mbulelo , Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/360411 , vital:65086 , xlink:href="https://doi.org/10.1002/elan.202200222"
- Description: Manganese and cobalt metalated 5, 10, 15-tris(aminophenyl)-20-(4-carboxyphenyl) porphyrins (ClMnTA3CPP and CoTA3CPP) were synthesized and attached to graphene quantum dots (GQDs) via π-π interaction and electrostatic interaction. The electrochemical oxidation of hydrazine was performed via cyclic voltammetry and chronoamperometry. The CoTA3CPP showed good electrocatalytic activity towards the oxidation of hydrazine in terms of catalytic rate constants and limits of detection (LoD). ClMnTA3CPP showed lower overpotential 0.60 V. The introduction of GQDs improved the electrocatalytic ability when combined with CoTA3CPP and ClMnTA3CPP with the lowest LoD (0.0025 mM CoTA3CPP–GQDs) followed by ClMnTA3CPP–GQDs with 0.0033 mM.
- Full Text:
- Date Issued: 2023