The views of amakrwala on the meaning of umqombothi and commercial alcohol use during the initiation ceremonies
- Authors: Mavimbela, Mzoli
- Date: 2021
- Subjects: Youth -- Alcohol use , Alcoholism -- South Africa , Alcoholism -- Psychological aspects , Initiation rites -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10948/60862 , vital:68801
- Description: Ulwaluko or initiation ceremony is one of the most important ceremonies practiced by the amaXhosa ethnic group to mark male adolescents’ transition from boyhood to manhood. Every young Xhosa male is anticipated to undergo this ceremony in order to be respected and be viewed as a true man by the society. There is a dearth of literature on amakrwala’s views regarding the meaning of traditional beer (umqombothi) and commercial alcohol (brandy or beer) use during the initiation ceremony. Thus, this study addresses this gap, as it adds to the existing spectrum of knowledge on the meaning of alcohol use during the amaXhosa initiation process. The socio-cultural theory was selected as the theoretical framework for the study. This study took a qualitative nature which was exploratory-descriptive and contextual in design employing a non-probability purposive-criterion based technique to sample 16 identified amaXhosa adult males between the ages of 18 to 24 years who recently went through the initiation ceremony. Sixteen individual semi-structured telephonic interviews were conducted. Data collected was analysed using thematic data analysis. Various data verification strategies were employed to ensure trustworthiness. Research ethics applicable to this study were guided by the principles contained in the Belmont report (1979). The findings showed that during the amaXhosa initiation ceremony both commercial alcohol and umqombothi played significant but different roles during each stage of the ceremony. The majority of amakrwala viewed umqombothi as a significant beer for ancestors to divinely bless isiko while brandy and beer were viewed as sweets or beers for fun which accompanied umqombothi. Brandy and beer were viewed as beers required by abafana teaching amakrwala manhood in the lighthouses. Thus, negative behaviours portrayed by abafana during imigidi after drinking alcohol were viewed as a great concern by amakrwala. 7 Alcohol use in ulwaluko was viewed as good by the amakrwala but they emphasized that there should be guidelines that monitor responsible drinking.
- Full Text:
- Date Issued: 2021
- Authors: Mavimbela, Mzoli
- Date: 2021
- Subjects: Youth -- Alcohol use , Alcoholism -- South Africa , Alcoholism -- Psychological aspects , Initiation rites -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , Degree
- Identifier: http://hdl.handle.net/10948/60862 , vital:68801
- Description: Ulwaluko or initiation ceremony is one of the most important ceremonies practiced by the amaXhosa ethnic group to mark male adolescents’ transition from boyhood to manhood. Every young Xhosa male is anticipated to undergo this ceremony in order to be respected and be viewed as a true man by the society. There is a dearth of literature on amakrwala’s views regarding the meaning of traditional beer (umqombothi) and commercial alcohol (brandy or beer) use during the initiation ceremony. Thus, this study addresses this gap, as it adds to the existing spectrum of knowledge on the meaning of alcohol use during the amaXhosa initiation process. The socio-cultural theory was selected as the theoretical framework for the study. This study took a qualitative nature which was exploratory-descriptive and contextual in design employing a non-probability purposive-criterion based technique to sample 16 identified amaXhosa adult males between the ages of 18 to 24 years who recently went through the initiation ceremony. Sixteen individual semi-structured telephonic interviews were conducted. Data collected was analysed using thematic data analysis. Various data verification strategies were employed to ensure trustworthiness. Research ethics applicable to this study were guided by the principles contained in the Belmont report (1979). The findings showed that during the amaXhosa initiation ceremony both commercial alcohol and umqombothi played significant but different roles during each stage of the ceremony. The majority of amakrwala viewed umqombothi as a significant beer for ancestors to divinely bless isiko while brandy and beer were viewed as sweets or beers for fun which accompanied umqombothi. Brandy and beer were viewed as beers required by abafana teaching amakrwala manhood in the lighthouses. Thus, negative behaviours portrayed by abafana during imigidi after drinking alcohol were viewed as a great concern by amakrwala. 7 Alcohol use in ulwaluko was viewed as good by the amakrwala but they emphasized that there should be guidelines that monitor responsible drinking.
- Full Text:
- Date Issued: 2021
Theories of Job Satisfaction In The Higher Education Context Education Context
- Asoba, Samson Nambei, Patricia, Nteboheng Mefi
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Motivation Job Satisfaction Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8125 , vital:61399 , xlink:href="https://www.abacademies.org/articles/the-primacy-of-effective-human-capital-management-to-the-growth-of-entrepreneurship-ventures-a-study-of-cases-from-the-fast-food-r-10259.html"
- Description: In South Africa, stagnant economic growth and high unemployment rates have called for solutions from all key national institutions, including institutions of higher learning, to provide solutions. This call must be considered within the transformation discourse that arose in South Africa after the fall of the apartheid regime in 1994 and the need to equalize educational opportunities, reduce poverty and improve lives through education. All this underscores the need for a vibrant motivated, satisfied and dedicated workforce. To explain and understand the phenomena of job-satisfaction several theories have been suggested by Maslow, Vroom, Adams, McGregor, Herzberg, Alderfer’s and other authors, however theories on employee job satisfaction varies with time and place, the old theory needs to be either modified, or replaced with a new model. The study attempt to synthesize the theories of job satisfaction in the Higher Education Institution in Eastern Cape Province in South Africa. The study adopted a desktop that was designed primarily as a descriptive study to source literatures on motivation, job satisfaction, and theories. Theories are neither right nor wrong rather it depends on the context where it is applied. Theories need to be restructured according to the new areas of research in human psychology. The evidence established from this study suggest theories of job satisfaction have to be tested against these emerging factors of positive psychology and their impact on human behaviour at individual, group and organizational levels in other Higher Education institutions in South Africa. Keywords: Motivation, Job Satisfaction, Theories, University.
- Full Text:
- Date Issued: 2021
- Authors: Asoba, Samson Nambei , Patricia, Nteboheng Mefi
- Date: 2021
- Subjects: Motivation Job Satisfaction Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/8125 , vital:61399 , xlink:href="https://www.abacademies.org/articles/the-primacy-of-effective-human-capital-management-to-the-growth-of-entrepreneurship-ventures-a-study-of-cases-from-the-fast-food-r-10259.html"
- Description: In South Africa, stagnant economic growth and high unemployment rates have called for solutions from all key national institutions, including institutions of higher learning, to provide solutions. This call must be considered within the transformation discourse that arose in South Africa after the fall of the apartheid regime in 1994 and the need to equalize educational opportunities, reduce poverty and improve lives through education. All this underscores the need for a vibrant motivated, satisfied and dedicated workforce. To explain and understand the phenomena of job-satisfaction several theories have been suggested by Maslow, Vroom, Adams, McGregor, Herzberg, Alderfer’s and other authors, however theories on employee job satisfaction varies with time and place, the old theory needs to be either modified, or replaced with a new model. The study attempt to synthesize the theories of job satisfaction in the Higher Education Institution in Eastern Cape Province in South Africa. The study adopted a desktop that was designed primarily as a descriptive study to source literatures on motivation, job satisfaction, and theories. Theories are neither right nor wrong rather it depends on the context where it is applied. Theories need to be restructured according to the new areas of research in human psychology. The evidence established from this study suggest theories of job satisfaction have to be tested against these emerging factors of positive psychology and their impact on human behaviour at individual, group and organizational levels in other Higher Education institutions in South Africa. Keywords: Motivation, Job Satisfaction, Theories, University.
- Full Text:
- Date Issued: 2021
Theorising Active Learning–A Historical Analysis
- Authors: Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435072 , vital:73128 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: There is no definitive or consensual Education for Sustainable Development (ESD) pedagogy but there is a suite of techniques which, if examined, will reveal similar features and principles. For example, in its ESD sourcebook, Unesco (2012) highlights pedagogies featuring question-orientated, analytical, critical and decisive skills, as well as relational pedagogies with features such as learner-centredness and participation. In its later Roadmap for Implementing the Global Action Programme for Education for Sustainable Development, Unesco calls for pedagogies that support the designing of ‘teaching and learning in an interactive, learner-centred way that enables exploratory, action-oriented and transformative learning’ (Unesco 2014: 12). An international collaborative group–ESD Expert-Net–highlighted the ‘active’ element of ESD arguing that ‘action’ or ‘doing’ elements of learning have traditionally been neglected, and that if ESD practice is to address local and global challenges ‘a strong action component’ is needed (Hoffmann and Rajeswari nd: 9). The notion of ‘active learning’has been of central interest in the Fundisa for Change project. This chapter describes its trajectory of development and use in South African ESD by outlining core features and principles for active learning. This is with a view to positioning the further chapters in this section of the book in relation to national and international research that has influenced the approach of Fundisa for Change. The chapter also serves to inform international interests in active learning.
- Full Text:
- Date Issued: 2021
- Authors: Schudel, Ingrid J
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/435072 , vital:73128 , ISBN 9781928502241 , https://library.oapen.org/handle/20.500.12657/64082
- Description: There is no definitive or consensual Education for Sustainable Development (ESD) pedagogy but there is a suite of techniques which, if examined, will reveal similar features and principles. For example, in its ESD sourcebook, Unesco (2012) highlights pedagogies featuring question-orientated, analytical, critical and decisive skills, as well as relational pedagogies with features such as learner-centredness and participation. In its later Roadmap for Implementing the Global Action Programme for Education for Sustainable Development, Unesco calls for pedagogies that support the designing of ‘teaching and learning in an interactive, learner-centred way that enables exploratory, action-oriented and transformative learning’ (Unesco 2014: 12). An international collaborative group–ESD Expert-Net–highlighted the ‘active’ element of ESD arguing that ‘action’ or ‘doing’ elements of learning have traditionally been neglected, and that if ESD practice is to address local and global challenges ‘a strong action component’ is needed (Hoffmann and Rajeswari nd: 9). The notion of ‘active learning’has been of central interest in the Fundisa for Change project. This chapter describes its trajectory of development and use in South African ESD by outlining core features and principles for active learning. This is with a view to positioning the further chapters in this section of the book in relation to national and international research that has influenced the approach of Fundisa for Change. The chapter also serves to inform international interests in active learning.
- Full Text:
- Date Issued: 2021
Thien-2-yl substituted chlorins as photosensitizers for photodynamic therapy and photodynamic antimicrobial chemotherapy
- Babu, Balaji, Sindelo, Azole, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Sindelo, Azole , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190578 , vital:45007 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108886"
- Description: The synthesis and characterization of meso-tetra(thien-2-yl)chlorin (1) and meso-tetra(5-bromothien-2-yl)chlorin (2) is reported. These dyes have red-shifted absorption maxima compared to those of the analogous meso-tetraphenylchlorin (3). 1 and 2 have Q bands at 660 and 664 nm, respectively, singlet oxygen quantum yields of 0.60 and 0.64 and exhibit good photostability. The triplet states were found to have lifetimes of 8.6 μs in N2 purged DMF. Time-dependent cellular uptake of chlorins reached a maximum in MCF-7 cancer cells after 12 h. Upon irradiation with a Thorlabs M660L3 LED (280 mW cm−2), 2 exhibited better photocytotoxicity with an IC50 value of 2.7 μM against MCF-7 cells. The 2ʹ,7ʹ-dichlorodihydrofluorescein diacetate (DCFDA) assay provided evidence for intracellular generation of reactive oxygen species. Photodynamic inactivation of bacteria by the chlorins was also studied. 2 exhibits better activity with log reduction values of 7.42 and 8.34 towards Staphylococcus aureus and Escherichia coli, respectively, under illumination for 60 min at 660 nm with a Thorlabs M660L3 LED (280 mW cm−2). These results demonstrate that 2 is a promising candidate for future in vivo experiments and merits further in-depth investigation.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Sindelo, Azole , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190578 , vital:45007 , xlink:href="https://doi.org/10.1016/j.dyepig.2020.108886"
- Description: The synthesis and characterization of meso-tetra(thien-2-yl)chlorin (1) and meso-tetra(5-bromothien-2-yl)chlorin (2) is reported. These dyes have red-shifted absorption maxima compared to those of the analogous meso-tetraphenylchlorin (3). 1 and 2 have Q bands at 660 and 664 nm, respectively, singlet oxygen quantum yields of 0.60 and 0.64 and exhibit good photostability. The triplet states were found to have lifetimes of 8.6 μs in N2 purged DMF. Time-dependent cellular uptake of chlorins reached a maximum in MCF-7 cancer cells after 12 h. Upon irradiation with a Thorlabs M660L3 LED (280 mW cm−2), 2 exhibited better photocytotoxicity with an IC50 value of 2.7 μM against MCF-7 cells. The 2ʹ,7ʹ-dichlorodihydrofluorescein diacetate (DCFDA) assay provided evidence for intracellular generation of reactive oxygen species. Photodynamic inactivation of bacteria by the chlorins was also studied. 2 exhibits better activity with log reduction values of 7.42 and 8.34 towards Staphylococcus aureus and Escherichia coli, respectively, under illumination for 60 min at 660 nm with a Thorlabs M660L3 LED (280 mW cm−2). These results demonstrate that 2 is a promising candidate for future in vivo experiments and merits further in-depth investigation.
- Full Text:
- Date Issued: 2021
Thirty years of Male Daughters, Female Husbands
- Magadla, Siphokazi, Magoqwana, Babalwa, Motsemme, Nthabiseng
- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298685 , vital:57727 , xlink:href="https://doi.org/10.1080/02589001.2021.1926442"
- Description: This paper examines the legacy of Ifi Amadiume's Male Daughters, Female Husbands: Gender and Sex in an African Society (1987) to African gender theorisation three decades after its publication. We argue that Amadiume's detailed ethnography of the Nnobi society provides an example of what can be achieved when African scholars centre local histories, languages, and kinship ties to provide contextualised understandings of sex and gender. In southern African societies, we assess the ways in which gender fluidity, drawing from local languages, age, seniority and lineage do not strictly fix sex to gender, thus providing possibilities for flexible gender structures that allow women to access institutions of power through the lineage as first daughters (umafungwashe) and wives, among others. We further examine the ways conservative patriarchal discourses continue distorting African cultures and traditions, thus undermining women's rights and access to social, cultural, economic and political power. We argue that current Eurocentric attempts that aim to delink sex and gender do not move us beyond the universalised binaries of gender and sex. Through revisiting local social and linguistic histories that practised gender fluidity and tolerance, we can also begin to challenge the conservative attitudes towards the LGBTQIA+ communities. Given the continued sexual and gender diversities that are being challenged daily in the African continent, it is timely that we revisit the historical meanings along with their contemporary implications for sexual citizenship and gendered power relations today.
- Full Text:
- Date Issued: 2021
- Authors: Magadla, Siphokazi , Magoqwana, Babalwa , Motsemme, Nthabiseng
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298685 , vital:57727 , xlink:href="https://doi.org/10.1080/02589001.2021.1926442"
- Description: This paper examines the legacy of Ifi Amadiume's Male Daughters, Female Husbands: Gender and Sex in an African Society (1987) to African gender theorisation three decades after its publication. We argue that Amadiume's detailed ethnography of the Nnobi society provides an example of what can be achieved when African scholars centre local histories, languages, and kinship ties to provide contextualised understandings of sex and gender. In southern African societies, we assess the ways in which gender fluidity, drawing from local languages, age, seniority and lineage do not strictly fix sex to gender, thus providing possibilities for flexible gender structures that allow women to access institutions of power through the lineage as first daughters (umafungwashe) and wives, among others. We further examine the ways conservative patriarchal discourses continue distorting African cultures and traditions, thus undermining women's rights and access to social, cultural, economic and political power. We argue that current Eurocentric attempts that aim to delink sex and gender do not move us beyond the universalised binaries of gender and sex. Through revisiting local social and linguistic histories that practised gender fluidity and tolerance, we can also begin to challenge the conservative attitudes towards the LGBTQIA+ communities. Given the continued sexual and gender diversities that are being challenged daily in the African continent, it is timely that we revisit the historical meanings along with their contemporary implications for sexual citizenship and gendered power relations today.
- Full Text:
- Date Issued: 2021
Three new biological control programmes for South Africa: Brazilian pepper, Tamarix and Tradescantia
- Byrne, Marcus J, Mayonde, Samalesu, Venter, Nic, Chidawanyika, Frank, Zachariades, Costas, Martin, Grant D
- Authors: Byrne, Marcus J , Mayonde, Samalesu , Venter, Nic , Chidawanyika, Frank , Zachariades, Costas , Martin, Grant D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414490 , vital:71152 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
- Description: Three weed biological control (biocontrol) programmes are described, all of which are considered to be ‘transfer projects’ that were initiated elsewhere, and on which South Africa has piggybacked its biocontrol efforts. Using knowledge and expertise from international collaborators, South African weed researchers are following a long tradition of transfer projects, which has been a largely successful and practical approach to biocontrol. Two Brazilian weeds, the Brazilian pepper tree Schinus terebinthifolia and the spiderwort Tradescantia fluminensis are being targeted, along with the Old-World trees Tamarix ramosissima and T. chinensis. The potential biocontrol agents are described and ranked for the two trees according to what has been discovered elsewhere, while the agent already released against T. fluminensis is rated (as poor), and other potential agents are considered. The addition of molecular techniques, climate matching and remote sensing in transfer projects can increase the chance of successful biocontrol and the inclusion of these techniques in the three new programmes is discussed. Transfer projects are a cost-effective and pragmatic way to pick winning biocontrol programmes.
- Full Text:
- Date Issued: 2021
Three new biological control programmes for South Africa: Brazilian pepper, Tamarix and Tradescantia
- Authors: Byrne, Marcus J , Mayonde, Samalesu , Venter, Nic , Chidawanyika, Frank , Zachariades, Costas , Martin, Grant D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/414490 , vital:71152 , xlink:href="https://hdl.handle.net/10520/ejc-cristal-v10-n1-a7"
- Description: Three weed biological control (biocontrol) programmes are described, all of which are considered to be ‘transfer projects’ that were initiated elsewhere, and on which South Africa has piggybacked its biocontrol efforts. Using knowledge and expertise from international collaborators, South African weed researchers are following a long tradition of transfer projects, which has been a largely successful and practical approach to biocontrol. Two Brazilian weeds, the Brazilian pepper tree Schinus terebinthifolia and the spiderwort Tradescantia fluminensis are being targeted, along with the Old-World trees Tamarix ramosissima and T. chinensis. The potential biocontrol agents are described and ranked for the two trees according to what has been discovered elsewhere, while the agent already released against T. fluminensis is rated (as poor), and other potential agents are considered. The addition of molecular techniques, climate matching and remote sensing in transfer projects can increase the chance of successful biocontrol and the inclusion of these techniques in the three new programmes is discussed. Transfer projects are a cost-effective and pragmatic way to pick winning biocontrol programmes.
- Full Text:
- Date Issued: 2021
Top-Down Synthesis of a Lamivudine-Zidovudine Nano Co-Crystal
- Witika, Bwalya A, Smith, Vincent J, Walker, Roderick B
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183172 , vital:43918 , xlink:href="https://doi.org/10.3390/cryst11010033"
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiretroviral agents used to manage HIV/AIDS infection. A wet media milling top-down approach was used to develop and produce nano co-crystals of 3TC and AZT. Micro co-crystals were prepared by solvent evaporation and subsequently milled in the presence of two surfactants, viz., sodium lauryl sulfate (SLS) and α-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000). Optimisation was undertaken using design of experiments (DoE) and response surface methodology (RSM) to establish and identify parameters that may affect the manufacturing of nano co-crystals. The impact of SLS and TPGS 1000 concentration, milling time, and number of units of milling medium on the manufacturing of nano co-crystals, was investigated. The critical quality attributes (CQA) monitored were particle size (PS), Zeta potential (ZP), and polydispersity index (PDI). Powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, transmission electron microscopy, energy dispersive X-ray spectroscopy scanning electron microscopy, and cytotoxicity assays were used for additional characterization of the optimised nano co-crystal. The mean PS, PDI, and ZP of the optimised top-down nanocrystal were 271.0 ± 92.0 nm, 0.467 ± 0.073, and −41.9 ± 3.94 mV, respectively. In conclusion, a simple, inexpensive, rapid, and precise method of nano co-crystal manufacturing was developed, validated, and optimised using DoE and RSM, and the final product exhibited the target CQA.
- Full Text:
- Date Issued: 2021
- Authors: Witika, Bwalya A , Smith, Vincent J , Walker, Roderick B
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183172 , vital:43918 , xlink:href="https://doi.org/10.3390/cryst11010033"
- Description: Lamivudine (3TC) and zidovudine (AZT) are antiretroviral agents used to manage HIV/AIDS infection. A wet media milling top-down approach was used to develop and produce nano co-crystals of 3TC and AZT. Micro co-crystals were prepared by solvent evaporation and subsequently milled in the presence of two surfactants, viz., sodium lauryl sulfate (SLS) and α-tocopheryl polyethylene glycol succinate 1000 (TPGS 1000). Optimisation was undertaken using design of experiments (DoE) and response surface methodology (RSM) to establish and identify parameters that may affect the manufacturing of nano co-crystals. The impact of SLS and TPGS 1000 concentration, milling time, and number of units of milling medium on the manufacturing of nano co-crystals, was investigated. The critical quality attributes (CQA) monitored were particle size (PS), Zeta potential (ZP), and polydispersity index (PDI). Powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, transmission electron microscopy, energy dispersive X-ray spectroscopy scanning electron microscopy, and cytotoxicity assays were used for additional characterization of the optimised nano co-crystal. The mean PS, PDI, and ZP of the optimised top-down nanocrystal were 271.0 ± 92.0 nm, 0.467 ± 0.073, and −41.9 ± 3.94 mV, respectively. In conclusion, a simple, inexpensive, rapid, and precise method of nano co-crystal manufacturing was developed, validated, and optimised using DoE and RSM, and the final product exhibited the target CQA.
- Full Text:
- Date Issued: 2021
Towards the Development of a Photovoltaic Array Fault Detection and Diagnosis (PVAFDD) System
- Ncube, Prince D N, Meyer, Edson L, Shibeshi, Zelalem S
- Authors: Ncube, Prince D N , Meyer, Edson L , Shibeshi, Zelalem S
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429105 , vital:72560 , https://ieeexplore.ieee.org/abstract/document/9698581
- Description: The perpetual increment in energy demand continues to put pressure on the South African Economy. Independent Power Producers (IPPs) have been contracted to relieve the strain by supplementing energy production using solar photovoltaic (PV) technologies. These IPPs are paid per megawatt they produce and face stiff penalties should they fail to deliver on contractual obligations. Naturally solar PV plants are susceptible to numerous PV faults that could lead to a negative return on investment. It therefore makes economic sense to adopt mechanisms that can be able to detect, localize and diagnose PV faults when they occur within a solar PV system. There exists an extensive literature on how to detect and diagnose PV faults, however, localizing PV faults is still in its infancy. This paper proposes to cater to the needs of the IPPs by developing an intelligent PV Array Fault Detection and Diagnostics (PVAFDD) system capable of localizing PV faults which can be embedded into the Supervisory Control and Data Acquisition (SCADA) system used to manage and control such PV systems. The PVAFDD system is based on a machine learning (ML) model implemented using logistic regression algorithm. The ML model is trained using meteorological data ranging over a period of eight years in Alice, Eastern Cape. Using simulations driven by real-life data scenarios, we have been able to train, validate and test the PVAFDD system. When the PVAFDD system detects a fault, a cascade of real-time PVA tests is undertaken to localize the PV fault. The system then carries out PVA fault diagnostics and gives recommendations on the PV fault classification. Corrective measures can therefore be implemented on the affected PVA swiftly reducing the downtime of the PV plant, ergo proving to be a cost-effective measure that offers a competitive edge to IPPs using the PVAFDD system.
- Full Text:
- Date Issued: 2021
- Authors: Ncube, Prince D N , Meyer, Edson L , Shibeshi, Zelalem S
- Date: 2021
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429105 , vital:72560 , https://ieeexplore.ieee.org/abstract/document/9698581
- Description: The perpetual increment in energy demand continues to put pressure on the South African Economy. Independent Power Producers (IPPs) have been contracted to relieve the strain by supplementing energy production using solar photovoltaic (PV) technologies. These IPPs are paid per megawatt they produce and face stiff penalties should they fail to deliver on contractual obligations. Naturally solar PV plants are susceptible to numerous PV faults that could lead to a negative return on investment. It therefore makes economic sense to adopt mechanisms that can be able to detect, localize and diagnose PV faults when they occur within a solar PV system. There exists an extensive literature on how to detect and diagnose PV faults, however, localizing PV faults is still in its infancy. This paper proposes to cater to the needs of the IPPs by developing an intelligent PV Array Fault Detection and Diagnostics (PVAFDD) system capable of localizing PV faults which can be embedded into the Supervisory Control and Data Acquisition (SCADA) system used to manage and control such PV systems. The PVAFDD system is based on a machine learning (ML) model implemented using logistic regression algorithm. The ML model is trained using meteorological data ranging over a period of eight years in Alice, Eastern Cape. Using simulations driven by real-life data scenarios, we have been able to train, validate and test the PVAFDD system. When the PVAFDD system detects a fault, a cascade of real-time PVA tests is undertaken to localize the PV fault. The system then carries out PVA fault diagnostics and gives recommendations on the PV fault classification. Corrective measures can therefore be implemented on the affected PVA swiftly reducing the downtime of the PV plant, ergo proving to be a cost-effective measure that offers a competitive edge to IPPs using the PVAFDD system.
- Full Text:
- Date Issued: 2021
Towards the development of a pro-environmental strategy for improving catch-and-release behaviour in recreational fisheries – a case study on a competitive South African angling body
- Authors: Mannheim, Samantha L
- Date: 2021
- Subjects: Fishing -- Environmental aspects -- South Africa , Fishing -- South Africa , Fishers -- Attitudes -- South Africa , Fishers -- Attitudes -- South Africa -- Cast studies , Fishes -- Conservation -- South Africa , Rock and Surf Super Pro League , Southern African Fisheries Ecology Research Lab
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171862 , vital:42133
- Description: Catch-and-release (C&R) is becoming increasingly popular in recreational fisheries with the potential to contribute towards conserving the oceans limited fish stocks. Several studies have highlighted high rates of mortality and many sub-lethal effects which ultimately have a negative impact on fish population viability. With poorly developed handling practices, the fish that are released suffer the consequences of physical and physiological stress and do not always survive, thus making the ethics of C&R fishing questionable. Many studies have contributed to our understanding of the factors that influence the fate of fish released by anglers. Despite this, few interventions have been able to improve angler C&R behaviour. Pro-environmental behavioural strategies however hold some potential for improving angler C&R behaviour. To test their potential, we partnered with the South African Rock and Surf Super Pro League (RASSPL Africa), the biggest exclusively C&R competitive shore-based angling league in South Africa. The first two years (2013 and 2014) of the partnership were purely focused on building trust and relationships and making observations on angler behaviour. In 2015, we collected baseline data on angler behaviour and fish health during the RASSPL national fishing competition. This was followed by comparable data collection at the following two national competitions in 2016 and 2017 after the introduction of a combination of pro- environmental behaviour interventions, including rule changes, improving angler knowledge, behavioural modelling, rewards, penalties and feedback to improve C&R behaviour. There were significant improvements in angler behaviour, including a decline in total air exposure from 101.93s ± 64.34 in 2015 to 77.37s ± 60.52 in 2017 (F(2,618) = 9.27, P < 0.01), and the time taken for an angler to place their fish into a bucket declined from 105.86s ± 69.47 in 2015 to 23.05s ± 24.13 in 2017 (F(2,556) = 158.71, P < 0.01). There were also improvements in the health of the fish, with a decline in the blood lactate concentration and mean reflex action mortality predictor (RAMP’s) scores for the dominant species, Diplodus capensis (lactate – 9.46 ± 3.80 mmol.l-1 in 2015 and 6.69 ± 2.99 mmol.l-1 in 2017, RAMP – 0.28 ± 0.22 in 2015 and 0.19 ± 0.17 in 2017), and Haploblapharus fuscus (lactate – 4.25 ± 1.89 mmol.l-1 in 2015 and 1.76 ± 0.78 mmol.l-1in 2017, RAMP – 0.15 ± 0.18 in 2015 and 0 ± 0 in 2017). In 2018, surveys were conducted to gain insight into angler demographics and external (social, economic, cultural and institutional) and internal factors (knowledge and awareness, motivations, attitudes and perceptions) associated with the RASSPL anglers. Surveys were also designed to assist in identifying what components were key drivers behind the angler’s behavioural changes. The demographic characteristics of RASSPL anglers were not dissimilar from the general recreational angling public in South Africa, suggesting that this kind of intervention may have potential at a broader scale. In terms of the drivers of behavioural change, the surveys revealed that 68% of respondents strongly agreed that the structural rule changes contributed to their improved behaviour. This was followed by the educational presentations (66% of the respondents) and modelling / demonstrative videos (59% of the respondents). The conservation prizes were considered less effective, with only 27% of anglers strongly agreeing that this intervention improved their C&R behaviour. Overall this study has demonstrated that it is possible to improve the C&R behaviour of anglers in a competitive setting, with the most effective component of the intervention being the use of rule changes (structural approach). These findings suggest that proenvironmental strategies hold potential for improving the C&R behaviour of anglers and the health of released fishes. It is suggested that interventions to improve C&R behaviour should aim to develop long-term relationships, and implement a broad range of well communicated strategies based on reliable data and sound rationality. Key words: marine shore-based fisheries; community engagement; pro- environmental behaviour; behavioural intervention.
- Full Text:
- Date Issued: 2021
- Authors: Mannheim, Samantha L
- Date: 2021
- Subjects: Fishing -- Environmental aspects -- South Africa , Fishing -- South Africa , Fishers -- Attitudes -- South Africa , Fishers -- Attitudes -- South Africa -- Cast studies , Fishes -- Conservation -- South Africa , Rock and Surf Super Pro League , Southern African Fisheries Ecology Research Lab
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171862 , vital:42133
- Description: Catch-and-release (C&R) is becoming increasingly popular in recreational fisheries with the potential to contribute towards conserving the oceans limited fish stocks. Several studies have highlighted high rates of mortality and many sub-lethal effects which ultimately have a negative impact on fish population viability. With poorly developed handling practices, the fish that are released suffer the consequences of physical and physiological stress and do not always survive, thus making the ethics of C&R fishing questionable. Many studies have contributed to our understanding of the factors that influence the fate of fish released by anglers. Despite this, few interventions have been able to improve angler C&R behaviour. Pro-environmental behavioural strategies however hold some potential for improving angler C&R behaviour. To test their potential, we partnered with the South African Rock and Surf Super Pro League (RASSPL Africa), the biggest exclusively C&R competitive shore-based angling league in South Africa. The first two years (2013 and 2014) of the partnership were purely focused on building trust and relationships and making observations on angler behaviour. In 2015, we collected baseline data on angler behaviour and fish health during the RASSPL national fishing competition. This was followed by comparable data collection at the following two national competitions in 2016 and 2017 after the introduction of a combination of pro- environmental behaviour interventions, including rule changes, improving angler knowledge, behavioural modelling, rewards, penalties and feedback to improve C&R behaviour. There were significant improvements in angler behaviour, including a decline in total air exposure from 101.93s ± 64.34 in 2015 to 77.37s ± 60.52 in 2017 (F(2,618) = 9.27, P < 0.01), and the time taken for an angler to place their fish into a bucket declined from 105.86s ± 69.47 in 2015 to 23.05s ± 24.13 in 2017 (F(2,556) = 158.71, P < 0.01). There were also improvements in the health of the fish, with a decline in the blood lactate concentration and mean reflex action mortality predictor (RAMP’s) scores for the dominant species, Diplodus capensis (lactate – 9.46 ± 3.80 mmol.l-1 in 2015 and 6.69 ± 2.99 mmol.l-1 in 2017, RAMP – 0.28 ± 0.22 in 2015 and 0.19 ± 0.17 in 2017), and Haploblapharus fuscus (lactate – 4.25 ± 1.89 mmol.l-1 in 2015 and 1.76 ± 0.78 mmol.l-1in 2017, RAMP – 0.15 ± 0.18 in 2015 and 0 ± 0 in 2017). In 2018, surveys were conducted to gain insight into angler demographics and external (social, economic, cultural and institutional) and internal factors (knowledge and awareness, motivations, attitudes and perceptions) associated with the RASSPL anglers. Surveys were also designed to assist in identifying what components were key drivers behind the angler’s behavioural changes. The demographic characteristics of RASSPL anglers were not dissimilar from the general recreational angling public in South Africa, suggesting that this kind of intervention may have potential at a broader scale. In terms of the drivers of behavioural change, the surveys revealed that 68% of respondents strongly agreed that the structural rule changes contributed to their improved behaviour. This was followed by the educational presentations (66% of the respondents) and modelling / demonstrative videos (59% of the respondents). The conservation prizes were considered less effective, with only 27% of anglers strongly agreeing that this intervention improved their C&R behaviour. Overall this study has demonstrated that it is possible to improve the C&R behaviour of anglers in a competitive setting, with the most effective component of the intervention being the use of rule changes (structural approach). These findings suggest that proenvironmental strategies hold potential for improving the C&R behaviour of anglers and the health of released fishes. It is suggested that interventions to improve C&R behaviour should aim to develop long-term relationships, and implement a broad range of well communicated strategies based on reliable data and sound rationality. Key words: marine shore-based fisheries; community engagement; pro- environmental behaviour; behavioural intervention.
- Full Text:
- Date Issued: 2021
Towards The Quantification Of The Historical And Future Water Resources Of The Limpopo River
- Kapangaziwiri, Evison, Kahinda, Jean-Marc M, Oosthuizen, Nadia, Mvandaba, Vuyelwa, Hobbs, Philip, Hughes, Denis A
- Authors: Kapangaziwiri, Evison , Kahinda, Jean-Marc M , Oosthuizen, Nadia , Mvandaba, Vuyelwa , Hobbs, Philip , Hughes, Denis A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438349 , vital:73453 , ISBN 978-0-6392-0303-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2439_final.pdf
- Description: The complexity of current water resource management poses many challenges. Wa-ter managers must solve a range of interrelated dilemmas – such as balancing quan-tity and quality, mitigating the effects of flooding and drought, and maintaining bio-diversity, ecological functions, and services. Sustainable water resource manage-ment, planning, and development requires reliable quantification of the amount, distribution, and quality of water within river basins. With the demand for water resources rapidly growing across the globe, there is also an urgent need for accu-rate monitoring, forecasting and simulation of hydrologic variables – especially in major (often transboundary) river basins such as the Limpopo – not only for optimal water resources management but more compellingly, also for water security, food security, power generation, and economic development. However, the available data are frequently far from sufficient – in terms of availability, accuracy, and spa-tial/temporal resolution – for the understanding of both natural and anthropogenic processes (and their complex linkages) in a river basin. Such challenges also make it very difficult to use the data for the practical application of estimation of water resources availability.
- Full Text:
- Date Issued: 2021
- Authors: Kapangaziwiri, Evison , Kahinda, Jean-Marc M , Oosthuizen, Nadia , Mvandaba, Vuyelwa , Hobbs, Philip , Hughes, Denis A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438349 , vital:73453 , ISBN 978-0-6392-0303-4 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2439_final.pdf
- Description: The complexity of current water resource management poses many challenges. Wa-ter managers must solve a range of interrelated dilemmas – such as balancing quan-tity and quality, mitigating the effects of flooding and drought, and maintaining bio-diversity, ecological functions, and services. Sustainable water resource manage-ment, planning, and development requires reliable quantification of the amount, distribution, and quality of water within river basins. With the demand for water resources rapidly growing across the globe, there is also an urgent need for accu-rate monitoring, forecasting and simulation of hydrologic variables – especially in major (often transboundary) river basins such as the Limpopo – not only for optimal water resources management but more compellingly, also for water security, food security, power generation, and economic development. However, the available data are frequently far from sufficient – in terms of availability, accuracy, and spa-tial/temporal resolution – for the understanding of both natural and anthropogenic processes (and their complex linkages) in a river basin. Such challenges also make it very difficult to use the data for the practical application of estimation of water resources availability.
- Full Text:
- Date Issued: 2021
Turn-on detection of cysteine by a donor-acceptor type quinoline fluorophore: Exploring the sensing strategy and performance in bioimaging
- Muthusamy, Selvaraj, Zhao, Long, Rajalakshmi, Kanagaraj, Zhu, Dongwei, Soy, Rodah, Mack, John, Nyokong, Tebello, Wang, Shengjun, Lee, Kang-Bong, Zhu, Weihua
- Authors: Muthusamy, Selvaraj , Zhao, Long , Rajalakshmi, Kanagaraj , Zhu, Dongwei , Soy, Rodah , Mack, John , Nyokong, Tebello , Wang, Shengjun , Lee, Kang-Bong , Zhu, Weihua
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185644 , vital:44406 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109556"
- Description: Tracking the biothiol cysteine (Cys) in living systems is a significant responsibility to balance the redox environment and oxidative stress. A quinoline-7-nitro-1,2,3-benzoxadiazole (Q-NBD) fluorophore has been synthesized and characterized towards examination of Cys. The probe forms a quinoline-substituted phenol (Q-Ph-OH) after thiolysis of the NBD ether bond, leading to an increase of fluorescence at green channel. The turn-on sensing mechanism originates from the change in intramolecular charge transfer (ICT-OFF) along with an aggregation-induced emission (AIE) as suggested by spectroscopy measurements in solutions, time-dependent density-functional theory (TD-DFT) calculations and 1H NMR titration examination. Importantly, Q-NBD exhibited great sensitivity with a low limit of detection value of 89.5 nM and remarkable selectivity in various biothiols towards Cys. The sensor probe was successfully used for detecting both endogenous and exogenous Cys in PC3 living cells and spiked Cys in human urine samples.
- Full Text:
- Date Issued: 2021
- Authors: Muthusamy, Selvaraj , Zhao, Long , Rajalakshmi, Kanagaraj , Zhu, Dongwei , Soy, Rodah , Mack, John , Nyokong, Tebello , Wang, Shengjun , Lee, Kang-Bong , Zhu, Weihua
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185644 , vital:44406 , xlink:href="https://doi.org/10.1016/j.dyepig.2021.109556"
- Description: Tracking the biothiol cysteine (Cys) in living systems is a significant responsibility to balance the redox environment and oxidative stress. A quinoline-7-nitro-1,2,3-benzoxadiazole (Q-NBD) fluorophore has been synthesized and characterized towards examination of Cys. The probe forms a quinoline-substituted phenol (Q-Ph-OH) after thiolysis of the NBD ether bond, leading to an increase of fluorescence at green channel. The turn-on sensing mechanism originates from the change in intramolecular charge transfer (ICT-OFF) along with an aggregation-induced emission (AIE) as suggested by spectroscopy measurements in solutions, time-dependent density-functional theory (TD-DFT) calculations and 1H NMR titration examination. Importantly, Q-NBD exhibited great sensitivity with a low limit of detection value of 89.5 nM and remarkable selectivity in various biothiols towards Cys. The sensor probe was successfully used for detecting both endogenous and exogenous Cys in PC3 living cells and spiked Cys in human urine samples.
- Full Text:
- Date Issued: 2021
Ultrasound-Triggered Release of 5-Fluorouracil from Soy Lecithin Echogenic Liposomes
- Ezekiel, Charles I, Bapolisi, Alain M, Walker, Roderick B, Krause, Rui W M
- Authors: Ezekiel, Charles I , Bapolisi, Alain M , Walker, Roderick B , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183115 , vital:43913 , xlink:href="https://doi.org/10.3390/pharmaceutics13060821"
- Description: Colorectal cancer is the third most diagnosed cancer and the second leading cause of death. The use of 5-fluorouracil (5-FU) has been the major chemotherapeutic treatment for colorectal cancer patients. However, the efficacy of 5-FU is limited by drug resistance, and bone marrow toxicity through high-level expression of thymidylate synthase, justifying the need for improvement of the therapeutic index. In this study, the effects of ultrasound on echogenic 5-FU encapsulated crude soy liposomes were investigated for their potential to address these challenges. Liposomes were prepared by thin-film hydration using crude soy lecithin and cholesterol. Argon gas was entrapped in the liposomes for sonosensitivity (that is, responsiveness to ultrasound). The nanoparticles were characterized for particle size and morphology. The physicochemical properties were also evaluated using differential scanning calorimetry, Fourier transform infrared and X-ray diffraction. The release profile of 5-FU was assessed with and without 20 kHz low-frequency ultrasound waves at various amplitudes and exposure times. The result reveal that 5-FU-loaded liposomes were spherical with an encapsulation efficiency of approximately 60%. Approximately 65% of 5-FU was released at the highest amplitude and exposure time was investigated. The results are encouraging for the stimulated and controlled release of 5-FU for the management of colorectal cancer.
- Full Text:
- Date Issued: 2021
- Authors: Ezekiel, Charles I , Bapolisi, Alain M , Walker, Roderick B , Krause, Rui W M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183115 , vital:43913 , xlink:href="https://doi.org/10.3390/pharmaceutics13060821"
- Description: Colorectal cancer is the third most diagnosed cancer and the second leading cause of death. The use of 5-fluorouracil (5-FU) has been the major chemotherapeutic treatment for colorectal cancer patients. However, the efficacy of 5-FU is limited by drug resistance, and bone marrow toxicity through high-level expression of thymidylate synthase, justifying the need for improvement of the therapeutic index. In this study, the effects of ultrasound on echogenic 5-FU encapsulated crude soy liposomes were investigated for their potential to address these challenges. Liposomes were prepared by thin-film hydration using crude soy lecithin and cholesterol. Argon gas was entrapped in the liposomes for sonosensitivity (that is, responsiveness to ultrasound). The nanoparticles were characterized for particle size and morphology. The physicochemical properties were also evaluated using differential scanning calorimetry, Fourier transform infrared and X-ray diffraction. The release profile of 5-FU was assessed with and without 20 kHz low-frequency ultrasound waves at various amplitudes and exposure times. The result reveal that 5-FU-loaded liposomes were spherical with an encapsulation efficiency of approximately 60%. Approximately 65% of 5-FU was released at the highest amplitude and exposure time was investigated. The results are encouraging for the stimulated and controlled release of 5-FU for the management of colorectal cancer.
- Full Text:
- Date Issued: 2021
Understanding the food crises in southern Africa and the ways of transitioning the food systems to combat hunger
- Chakona, Gamuchirai, Mushangai, Dandira
- Authors: Chakona, Gamuchirai , Mushangai, Dandira
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , working paper
- Identifier: http://hdl.handle.net/10962/433956 , vital:73014 , ISBN working paper
- Description: Globally, almost one billion people are estimated to face hunger on a regular basis (Poppy et al., 2014) and more than two billion people suffer from micronutrient deficiencies (Barrett, 2010; FAO et al. 2020). The number of food-insecure people has been on the rise with subSaharan Africa having the greatest number of individuals who are both hungry (about 237 million people) and malnourished (almost 23% of the population) (FAO, 2018). Beyond hunger, FAO et al. (2020) noted that a growing number of people have had to reduce the quantity and quality of the food they consume. This makes it almost impossible to have a world with zero hunger by 2030 and achieve SDG 2 target 2.1 of ensuring access to safe, nutritious and sufficient food for all people and target 2.2 of eradicating all forms of malnutrition (UN 2015). Most governments globally have pledged to eradicate hunger in their nations by 2030, and one of their solutions is to increase agricultural productivity to meet the needs of all their people. However, Poppy et al. (2014) argued that increased yields and food supplies do not assure food security for all as some poorer societies and communities may not have access to sufficient quantity or quality food (Iram and Butt, 2004), which is a challenge in many African communities, especially in South Africa. This highlights the complexity of the food system within many countries.
- Full Text:
- Date Issued: 2021
- Authors: Chakona, Gamuchirai , Mushangai, Dandira
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , working paper
- Identifier: http://hdl.handle.net/10962/433956 , vital:73014 , ISBN working paper
- Description: Globally, almost one billion people are estimated to face hunger on a regular basis (Poppy et al., 2014) and more than two billion people suffer from micronutrient deficiencies (Barrett, 2010; FAO et al. 2020). The number of food-insecure people has been on the rise with subSaharan Africa having the greatest number of individuals who are both hungry (about 237 million people) and malnourished (almost 23% of the population) (FAO, 2018). Beyond hunger, FAO et al. (2020) noted that a growing number of people have had to reduce the quantity and quality of the food they consume. This makes it almost impossible to have a world with zero hunger by 2030 and achieve SDG 2 target 2.1 of ensuring access to safe, nutritious and sufficient food for all people and target 2.2 of eradicating all forms of malnutrition (UN 2015). Most governments globally have pledged to eradicate hunger in their nations by 2030, and one of their solutions is to increase agricultural productivity to meet the needs of all their people. However, Poppy et al. (2014) argued that increased yields and food supplies do not assure food security for all as some poorer societies and communities may not have access to sufficient quantity or quality food (Iram and Butt, 2004), which is a challenge in many African communities, especially in South Africa. This highlights the complexity of the food system within many countries.
- Full Text:
- Date Issued: 2021
Unlocking the Diversity of Pyrroloiminoquinones Produced by Latrunculid Sponge Species
- Kalinski, Jarmo-Charles J, Krause, Rui W M, Parker-Nance, Shirley, Waterworth, Samantha C, Dorrington, Rosemary A
- Authors: Kalinski, Jarmo-Charles J , Krause, Rui W M , Parker-Nance, Shirley , Waterworth, Samantha C , Dorrington, Rosemary A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191802 , vital:45165 , xlink:href="https://doi.org/10.3390/md19020068"
- Description: Sponges of the Latrunculiidae family produce bioactive pyrroloiminoquinone alkaloids including makaluvamines, discorhabdins, and tsitsikammamines. The aim of this study was to use LC-ESI-MS/MS-driven molecular networking to characterize the pyrroloiminoquinone secondary metabolites produced by six latrunculid species. These are Tsitsikamma favus, Tsitsikamma pedunculata, Cyclacanthia bellae, and Latrunculia apicalis as well as the recently discovered species, Tsitsikamma nguni and Tsitsikamma michaeli. Organic extracts of 43 sponges were analyzed, revealing distinct species-specific chemical profiles. More than 200 known and unknown putative pyrroloiminoquinones and related compounds were detected, including unprecedented makaluvamine-discorhabdin adducts and hydroxylated discorhabdin I derivatives. The chemical profiles of the new species T. nguni closely resembled those of the known T. favus (chemotype I), but with a higher abundance of tsitsikammamines vs. discorhabdins. T. michaeli sponges displayed two distinct chemical profiles, either producing mostly the same discorhabdins as T. favus (chemotype I) or non- or monobrominated, hydroxylated discorhabdins. C. bellae and L. apicalis produced similar pyrroloiminoquinone chemistry to one another, characterized by sulfur-containing discorhabdins and related adducts and oligomers. This study highlights the variability of pyrroloiminoquinone production by latrunculid species, identifies novel isolation targets, and offers fundamental insights into the collision-induced dissociation of pyrroloiminoquinones.
- Full Text:
- Date Issued: 2021
- Authors: Kalinski, Jarmo-Charles J , Krause, Rui W M , Parker-Nance, Shirley , Waterworth, Samantha C , Dorrington, Rosemary A
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191802 , vital:45165 , xlink:href="https://doi.org/10.3390/md19020068"
- Description: Sponges of the Latrunculiidae family produce bioactive pyrroloiminoquinone alkaloids including makaluvamines, discorhabdins, and tsitsikammamines. The aim of this study was to use LC-ESI-MS/MS-driven molecular networking to characterize the pyrroloiminoquinone secondary metabolites produced by six latrunculid species. These are Tsitsikamma favus, Tsitsikamma pedunculata, Cyclacanthia bellae, and Latrunculia apicalis as well as the recently discovered species, Tsitsikamma nguni and Tsitsikamma michaeli. Organic extracts of 43 sponges were analyzed, revealing distinct species-specific chemical profiles. More than 200 known and unknown putative pyrroloiminoquinones and related compounds were detected, including unprecedented makaluvamine-discorhabdin adducts and hydroxylated discorhabdin I derivatives. The chemical profiles of the new species T. nguni closely resembled those of the known T. favus (chemotype I), but with a higher abundance of tsitsikammamines vs. discorhabdins. T. michaeli sponges displayed two distinct chemical profiles, either producing mostly the same discorhabdins as T. favus (chemotype I) or non- or monobrominated, hydroxylated discorhabdins. C. bellae and L. apicalis produced similar pyrroloiminoquinone chemistry to one another, characterized by sulfur-containing discorhabdins and related adducts and oligomers. This study highlights the variability of pyrroloiminoquinone production by latrunculid species, identifies novel isolation targets, and offers fundamental insights into the collision-induced dissociation of pyrroloiminoquinones.
- Full Text:
- Date Issued: 2021
Urban birds in the Eastern Cape: local observations from Makhanda (Grahamstown) and future questions
- Craig, Adrian J F K, Hulley, Patrick E, Mullins, R Lorraine G
- Authors: Craig, Adrian J F K , Hulley, Patrick E , Mullins, R Lorraine G
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449580 , vital:74831 , https://doi.org/10.2989/00306525.2020.1816585
- Description: In Makhanda (Grahamstown), a non-industrial town with approximately 85 000 inhabitants, we have recorded 174 bird species within the urban area, of which 104 species are likely to breed regularly. The source habitats of these birds include all the surrounding habitat types, and the bird community is evidently determined by both local conditions within the town (e.g. tree density) and regional changes affecting the eastern coast of South Africa (range shifts). Topics meriting future research on urban bird communities in South Africa are highlighted.
- Full Text:
- Date Issued: 2021
Urban birds in the Eastern Cape: local observations from Makhanda (Grahamstown) and future questions
- Authors: Craig, Adrian J F K , Hulley, Patrick E , Mullins, R Lorraine G
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/449580 , vital:74831 , https://doi.org/10.2989/00306525.2020.1816585
- Description: In Makhanda (Grahamstown), a non-industrial town with approximately 85 000 inhabitants, we have recorded 174 bird species within the urban area, of which 104 species are likely to breed regularly. The source habitats of these birds include all the surrounding habitat types, and the bird community is evidently determined by both local conditions within the town (e.g. tree density) and regional changes affecting the eastern coast of South Africa (range shifts). Topics meriting future research on urban bird communities in South Africa are highlighted.
- Full Text:
- Date Issued: 2021
Urban ecology of the Global South
- du Toit, Marie J, Shackleton, Charlie M, Cilliers, Sarel S, Davoren, Elandre
- Authors: du Toit, Marie J , Shackleton, Charlie M , Cilliers, Sarel S , Davoren, Elandre
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/433728 , vital:72997 , ISBN 978-3-030-67650-6 , https://doi.org/10.1007/978-3-030-67650-6
- Description: Against the background of unprecedented rates of urbanisation in the Global South, leading to massive social, economic and environmental transformations, this book engages with the dire need to understand the ecology of such settings as the foundation for fostering sustainable and resilient human settlements in contexts that are very different to the Global North. It does so by bringing together scholars from around the world, drawing together research and case studies from across the Global South to illustrate, in an interdisciplinary and comprehensive fashion, the ecology of towns and cities in the Global South. Framed using a social-ecological systems lens, it provides the reader with an in-depth analysis and understanding of the ecological dynamics and ecosystem services and disservices within the complex and rapidly changing towns and cities of the Global South, a region with currently scarce representation in most of the urban ecology literature. As such the book makes a call for greater geographical balance in urban ecology research leading towards a more global understanding and frameworks. The book embraces the complexity of these rapid transformations for ecological and environmental management and how the ecosystems and the benefits they provide shape local ecologies, livelihood opportunities and human wellbeing, and how such knowledge can be mobilised towards improved urban design and management and thus urban sustainability.
- Full Text:
- Date Issued: 2021
- Authors: du Toit, Marie J , Shackleton, Charlie M , Cilliers, Sarel S , Davoren, Elandre
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/433728 , vital:72997 , ISBN 978-3-030-67650-6 , https://doi.org/10.1007/978-3-030-67650-6
- Description: Against the background of unprecedented rates of urbanisation in the Global South, leading to massive social, economic and environmental transformations, this book engages with the dire need to understand the ecology of such settings as the foundation for fostering sustainable and resilient human settlements in contexts that are very different to the Global North. It does so by bringing together scholars from around the world, drawing together research and case studies from across the Global South to illustrate, in an interdisciplinary and comprehensive fashion, the ecology of towns and cities in the Global South. Framed using a social-ecological systems lens, it provides the reader with an in-depth analysis and understanding of the ecological dynamics and ecosystem services and disservices within the complex and rapidly changing towns and cities of the Global South, a region with currently scarce representation in most of the urban ecology literature. As such the book makes a call for greater geographical balance in urban ecology research leading towards a more global understanding and frameworks. The book embraces the complexity of these rapid transformations for ecological and environmental management and how the ecosystems and the benefits they provide shape local ecologies, livelihood opportunities and human wellbeing, and how such knowledge can be mobilised towards improved urban design and management and thus urban sustainability.
- Full Text:
- Date Issued: 2021
Urban ecosystem disservices in the Global South
- Davoren, Elandre, Shackleton, Charlie M
- Authors: Davoren, Elandre , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433780 , vital:73000 , ISBN 978-3-030-67650-6 , https://doi.org/10.1007/978-3-030-67650-6_11
- Description: As much as people benefit from the ecosystem services provided by nature, ecosystem disservices also impact daily lives. This is especially true for many urban communities in the Global South due to (1) the often greater diversity of ecosystem disservices and (2) higher vulnerabilities, which together can lead to greater impacts of ecosystem disservices in many Global South settings. This chapter provides an overview of the current understandings of urban ecosystem disservices and their assessment and management with an emphasis on the Global South, albeit with reference to the Global North where useful. This overview reveals a lack of detailed and systematic empirical research on urban ecosystem disservices generally, but even more so in the Global South, despite the greater diversity and vulnerability in Global South settings. This needs to be acknowledged in urban ecology framings of urban dynamics in the Global South and translated into better integration of both ecosystem services and disservices within common research, policy or management frameworks. It is only through such integration that appropriate context-relevant policy directions and management options can be identified, thereby promoting the wellbeing of urban citizens in the Global South.
- Full Text:
- Date Issued: 2021
- Authors: Davoren, Elandre , Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433780 , vital:73000 , ISBN 978-3-030-67650-6 , https://doi.org/10.1007/978-3-030-67650-6_11
- Description: As much as people benefit from the ecosystem services provided by nature, ecosystem disservices also impact daily lives. This is especially true for many urban communities in the Global South due to (1) the often greater diversity of ecosystem disservices and (2) higher vulnerabilities, which together can lead to greater impacts of ecosystem disservices in many Global South settings. This chapter provides an overview of the current understandings of urban ecosystem disservices and their assessment and management with an emphasis on the Global South, albeit with reference to the Global North where useful. This overview reveals a lack of detailed and systematic empirical research on urban ecosystem disservices generally, but even more so in the Global South, despite the greater diversity and vulnerability in Global South settings. This needs to be acknowledged in urban ecology framings of urban dynamics in the Global South and translated into better integration of both ecosystem services and disservices within common research, policy or management frameworks. It is only through such integration that appropriate context-relevant policy directions and management options can be identified, thereby promoting the wellbeing of urban citizens in the Global South.
- Full Text:
- Date Issued: 2021
Urban green infrastructure for poverty alleviation: evidence synthesis and conceptual considerations
- Authors: Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401383 , vital:69730 , xlink:href="https://doi.org/10.3389/frsc.2021.710549"
- Description: The multiple benefits of urban green infrastructure (UGI) that support sustainable cities are increasingly acknowledged, and yet the bulk of research over the past decade or so has focused on only a small subset of the numerous benefits, notably recreation, physical and mental health, and regulating services. In contrast, there is very little information on the contribution of UGI to several of the other Sustainable Development Goals (SDGs), and in particular SDG 1 of reducing poverty, despite the pervasiveness of poverty globally. This paper considers the diverse direct and indirect ways in which UGI can contribute to poverty alleviation, drawing on the limited evidence from various regions of the world. The direct links between UGI and poverty alleviation is via three means, namely provision of (1) consumptive or provisioning goods such as wild foods and firewood, (2) employment in UGI development, maintenance, and restoration, and (3) land for urban agriculture, income generation and dwelling. There are also a number of indirect links such as cash savings, improved physical and mental health, improved social networks, improved educational outcomes, and regulation of potential natural disasters. However, the commonly unequal distribution of UGI within and between cities means that the poverty alleviation potential and benefits are inequitably distributed, often against those who are most in need of them, i.e., the urban poor. This demands greater attention to promoting the equitable distribution and quality of UGI and mainstreaming of UGI into poverty reduction strategies and programmes and vice versa, as well as greater examination of the links between UGI and poverty alleviation in a greater range of contexts.
- Full Text:
- Date Issued: 2021
Urban green infrastructure for poverty alleviation: evidence synthesis and conceptual considerations
- Authors: Shackleton, Charlie M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/401383 , vital:69730 , xlink:href="https://doi.org/10.3389/frsc.2021.710549"
- Description: The multiple benefits of urban green infrastructure (UGI) that support sustainable cities are increasingly acknowledged, and yet the bulk of research over the past decade or so has focused on only a small subset of the numerous benefits, notably recreation, physical and mental health, and regulating services. In contrast, there is very little information on the contribution of UGI to several of the other Sustainable Development Goals (SDGs), and in particular SDG 1 of reducing poverty, despite the pervasiveness of poverty globally. This paper considers the diverse direct and indirect ways in which UGI can contribute to poverty alleviation, drawing on the limited evidence from various regions of the world. The direct links between UGI and poverty alleviation is via three means, namely provision of (1) consumptive or provisioning goods such as wild foods and firewood, (2) employment in UGI development, maintenance, and restoration, and (3) land for urban agriculture, income generation and dwelling. There are also a number of indirect links such as cash savings, improved physical and mental health, improved social networks, improved educational outcomes, and regulation of potential natural disasters. However, the commonly unequal distribution of UGI within and between cities means that the poverty alleviation potential and benefits are inequitably distributed, often against those who are most in need of them, i.e., the urban poor. This demands greater attention to promoting the equitable distribution and quality of UGI and mainstreaming of UGI into poverty reduction strategies and programmes and vice versa, as well as greater examination of the links between UGI and poverty alleviation in a greater range of contexts.
- Full Text:
- Date Issued: 2021
Visible light responsive TiO2-graphene oxide nanosheets-Zn phthalocyanine ternary heterojunction assisted photoelectrocatalytic degradation of Orange G
- Nwahara, Nnamdi, Adeniyi, Omotayo, Mashazi, Philani N, Nyokong, Tebello
- Authors: Nwahara, Nnamdi , Adeniyi, Omotayo , Mashazi, Philani N , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185446 , vital:44387 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113291"
- Description: Herein, we report on the successful fabrication of a visible light-responsive TiO2 - graphene oxide nanosheets – Zn phthalocyanine (TiO2@GONS@ZnPc) ternary structure for the photoelectrochemical degradation of Orange G azo dye. The characterization of TiO2@GONS@ZnPc composite was achieved using various spectroscopic and microscopic techniques. Our results show that the TiO2@GONS@ZnPc surface hybrid heterojunction promotes charge separation and electron migration, significantly improving the degradation efficiency with an applied potential. For the first time, we show the existence of a non-radical activation route for persulfate (PS) using such π electron-rich ZnPc-GONS catalysts. The degradation kinetics were found to follow pseudo first order kinetics. Electron spin resonance analyses suggested that neither hydroxyl radicals nor sulfate radicals were produced therein, and therefore were not responsible for the persulfate-driven oxidation of the OG dye. These findings suggest that both which GONS and ZnPc play a critical role in mediating the eventual charge transfer mediated PS activation. The results illustrate the remarkable capacity of the TiO2@GONS@ZnPc composite to rapidly degrade Orange G by a coupled TiO2@GONS@ZnPc-persulfate system.
- Full Text:
- Date Issued: 2021
- Authors: Nwahara, Nnamdi , Adeniyi, Omotayo , Mashazi, Philani N , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185446 , vital:44387 , xlink:href="https://doi.org/10.1016/j.jphotochem.2021.113291"
- Description: Herein, we report on the successful fabrication of a visible light-responsive TiO2 - graphene oxide nanosheets – Zn phthalocyanine (TiO2@GONS@ZnPc) ternary structure for the photoelectrochemical degradation of Orange G azo dye. The characterization of TiO2@GONS@ZnPc composite was achieved using various spectroscopic and microscopic techniques. Our results show that the TiO2@GONS@ZnPc surface hybrid heterojunction promotes charge separation and electron migration, significantly improving the degradation efficiency with an applied potential. For the first time, we show the existence of a non-radical activation route for persulfate (PS) using such π electron-rich ZnPc-GONS catalysts. The degradation kinetics were found to follow pseudo first order kinetics. Electron spin resonance analyses suggested that neither hydroxyl radicals nor sulfate radicals were produced therein, and therefore were not responsible for the persulfate-driven oxidation of the OG dye. These findings suggest that both which GONS and ZnPc play a critical role in mediating the eventual charge transfer mediated PS activation. The results illustrate the remarkable capacity of the TiO2@GONS@ZnPc composite to rapidly degrade Orange G by a coupled TiO2@GONS@ZnPc-persulfate system.
- Full Text:
- Date Issued: 2021
What are social-ecological systems and social-ecological systems research
- Biggs, Reinette, Clements, Hayley, de Vos, Alta, Folke, Carl, Manyani, Amanda, Maciejewski, Kristine, Martin-Lopez, Berta, Preiser, Rika, Selomane, Odirilwe, Schluter, Maja
- Authors: Biggs, Reinette , Clements, Hayley , de Vos, Alta , Folke, Carl , Manyani, Amanda , Maciejewski, Kristine , Martin-Lopez, Berta , Preiser, Rika , Selomane, Odirilwe , Schluter, Maja
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433900 , vital:73008 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: The period since the Second World War has been marked by rapid and accelerating changes to many aspects of human society and the environment (Clark, Crutzen, and Schellnhuber 2004; Steffen et al. 2011; Steffen et al. 2015a). There is accumulating evidence and rising concern about the potential consequences these changes hold for key Earth system processes at a global scale, and human well-being and prosperity into the future (Krausmann et al. 2013; Steffen et al. 2015b). The Anthropocene, as this new era of extensive human impact on the Earth has come to be known (Crutzen 2006), manifests in a closely intertwined set of social and ecological changes. Technological advances, increasing human population, rising levels of wealth and consumption, and the institutional arrangements we have developed to govern our economies and societies interplay with one another, and drastically affect the Earth’s climate, biological diversity, fresh-water and biogeochemical flows, and levels of novel pollutants in the environment (Steffen et al. 2015a). These environmental changes, in turn, contribute to increasingly frequent and severe droughts (Dai 2013; Trenberth et al. 2014), floods (Milly et al. 2002; Nicholls 2004), heatwaves (Guo et al. 2018; Oliver et al. 2018) and the emergence of novel pathogens such as SARS-CoV-2 (Everard et al. 2020; O ’Callaghan-Gordo and Antò 2020; Schmeller, Courchamp, and Killeen 2020) that can lead to massive societal disruption and hardship, especially among the poor (Wheeler and Von Braun 2013; Barbier and Hochard 2018).
- Full Text:
- Date Issued: 2021
- Authors: Biggs, Reinette , Clements, Hayley , de Vos, Alta , Folke, Carl , Manyani, Amanda , Maciejewski, Kristine , Martin-Lopez, Berta , Preiser, Rika , Selomane, Odirilwe , Schluter, Maja
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433900 , vital:73008 , ISBN 9781000401516 , https://library.oapen.org/handle/20.500.12657/49560
- Description: The period since the Second World War has been marked by rapid and accelerating changes to many aspects of human society and the environment (Clark, Crutzen, and Schellnhuber 2004; Steffen et al. 2011; Steffen et al. 2015a). There is accumulating evidence and rising concern about the potential consequences these changes hold for key Earth system processes at a global scale, and human well-being and prosperity into the future (Krausmann et al. 2013; Steffen et al. 2015b). The Anthropocene, as this new era of extensive human impact on the Earth has come to be known (Crutzen 2006), manifests in a closely intertwined set of social and ecological changes. Technological advances, increasing human population, rising levels of wealth and consumption, and the institutional arrangements we have developed to govern our economies and societies interplay with one another, and drastically affect the Earth’s climate, biological diversity, fresh-water and biogeochemical flows, and levels of novel pollutants in the environment (Steffen et al. 2015a). These environmental changes, in turn, contribute to increasingly frequent and severe droughts (Dai 2013; Trenberth et al. 2014), floods (Milly et al. 2002; Nicholls 2004), heatwaves (Guo et al. 2018; Oliver et al. 2018) and the emergence of novel pathogens such as SARS-CoV-2 (Everard et al. 2020; O ’Callaghan-Gordo and Antò 2020; Schmeller, Courchamp, and Killeen 2020) that can lead to massive societal disruption and hardship, especially among the poor (Wheeler and Von Braun 2013; Barbier and Hochard 2018).
- Full Text:
- Date Issued: 2021