Evaluating the physiological, morphological and nutritional effects of elevated atmospheric CO2 and drought on select South African maize cultivars
- Authors: Bopape, Tebadi Mamadiga
- Date: 2021-10
- Subjects: Corn Varieties South Africa , Dry farming South Africa , Corn Effect of atmospheric carbon dioxide on South Africa , Corn Effect of drought on South Africa , Corn Morphology , Corn Nutrition , Corn Physiological effect
- Language: English
- Type: Master theses , text
- Identifier: http://hdl.handle.net/10962/189020 , vital:44807
- Description: Thesis embargoed. Expected Release date October 2022. , Thesis (MSc) -- Faculty of Science, Botany, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Bopape, Tebadi Mamadiga
- Date: 2021-10
- Subjects: Corn Varieties South Africa , Dry farming South Africa , Corn Effect of atmospheric carbon dioxide on South Africa , Corn Effect of drought on South Africa , Corn Morphology , Corn Nutrition , Corn Physiological effect
- Language: English
- Type: Master theses , text
- Identifier: http://hdl.handle.net/10962/189020 , vital:44807
- Description: Thesis embargoed. Expected Release date October 2022. , Thesis (MSc) -- Faculty of Science, Botany, 2021
- Full Text:
- Date Issued: 2021-10
Addressing the Twin Challenges of Poverty and Unemployment through Community Work Programmes in South Africa :
- Tshishonga, Ndwakhulu, Matsiliza, Noluthando S
- Authors: Tshishonga, Ndwakhulu , Matsiliza, Noluthando S
- Date: 2021-06
- Subjects: South Africa Poverty Equality Community organization Livelihoods Public Works Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7424 , vital:53961 , https://doi.org/10.31920/2634-3649/2021/v11n2a12
- Description: This paper interrogates gaps in the implementing community work programmes in South Africa using the case of the Expanded Public Works Programme (EPWP) and Community Work Programmes (CWP). The EPWP and CWPs were adopted by government as strategies aimed at uprooting poverty and unemployment in South Africa. The intention was to respond to high levels of poverty and structural unemployment compounded by gross inequity which renders South Africa the most unequal society in the world. South Africa is characterised by inequality, poverty and unemployment, and this has created an uneven allocation of resources to society at large. The interface of poverty, unemployment and inequality undermines South Africa’s policies to become a developmental state. This paper argues that the legacy of apartheid and the adoption of neo-liberal policies in the post-apartheid era has not only contributed to socio-economic exclusion and marginalisation, but also relegate the poor and disadvantaged people into the deprivation trap. The paper evaluates the potential and challenges faced by EPWP, and the CWP to address the twin problems of poverty and unemployment in the country. Authors of this paper adopted a qualitative research approach to review literature from various sources such as books, articles from accredited journals and online credible publications. To respond to the aim, this paper argues that, although community-based work programmes such as the Expanded Public Works Programme and Community Work do not sustain employment opportunities in South Africa, they provide short-term safety nets for the unemployed, semi-skilled and unskilled citizens. Findings from this study revealed that community development work is not successful in achieving all the goals that are directly linked to poverty alleviation at programme level. Challenges found to be stifling the effective implementation of community work programmes included the implementation of the programmes at small scale, lack of active participation by unemployed and host communities, poor coordination and inadequate adequate infrastructure and resources to run the programmes effectively as we as well limited access to resources, assets and skills that can be jointly used to sustain the economy. The paper recommends the adoption of pluralistic approach in promoting active participation among community work programmes’ stakeholders. This a literature review paper hence secondary sources of data were used.
- Full Text:
- Date Issued: 2021-06
- Authors: Tshishonga, Ndwakhulu , Matsiliza, Noluthando S
- Date: 2021-06
- Subjects: South Africa Poverty Equality Community organization Livelihoods Public Works Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7424 , vital:53961 , https://doi.org/10.31920/2634-3649/2021/v11n2a12
- Description: This paper interrogates gaps in the implementing community work programmes in South Africa using the case of the Expanded Public Works Programme (EPWP) and Community Work Programmes (CWP). The EPWP and CWPs were adopted by government as strategies aimed at uprooting poverty and unemployment in South Africa. The intention was to respond to high levels of poverty and structural unemployment compounded by gross inequity which renders South Africa the most unequal society in the world. South Africa is characterised by inequality, poverty and unemployment, and this has created an uneven allocation of resources to society at large. The interface of poverty, unemployment and inequality undermines South Africa’s policies to become a developmental state. This paper argues that the legacy of apartheid and the adoption of neo-liberal policies in the post-apartheid era has not only contributed to socio-economic exclusion and marginalisation, but also relegate the poor and disadvantaged people into the deprivation trap. The paper evaluates the potential and challenges faced by EPWP, and the CWP to address the twin problems of poverty and unemployment in the country. Authors of this paper adopted a qualitative research approach to review literature from various sources such as books, articles from accredited journals and online credible publications. To respond to the aim, this paper argues that, although community-based work programmes such as the Expanded Public Works Programme and Community Work do not sustain employment opportunities in South Africa, they provide short-term safety nets for the unemployed, semi-skilled and unskilled citizens. Findings from this study revealed that community development work is not successful in achieving all the goals that are directly linked to poverty alleviation at programme level. Challenges found to be stifling the effective implementation of community work programmes included the implementation of the programmes at small scale, lack of active participation by unemployed and host communities, poor coordination and inadequate adequate infrastructure and resources to run the programmes effectively as we as well limited access to resources, assets and skills that can be jointly used to sustain the economy. The paper recommends the adoption of pluralistic approach in promoting active participation among community work programmes’ stakeholders. This a literature review paper hence secondary sources of data were used.
- Full Text:
- Date Issued: 2021-06
Atypical HIV-vacuolar myelopathy: a case report :
- Mongezi, Tau, Sibi, Joseph, Jerry, George, Lourdes de Fátima, Ibañez Valdés, Tozama, Dubula, Humberto, Foyaca Sibat
- Authors: Mongezi, Tau , Sibi, Joseph , Jerry, George , Lourdes de Fátima, Ibañez Valdés , Tozama, Dubula , Humberto, Foyaca Sibat
- Date: 2021-06
- Subjects: South Africa HIV (Viruses) Cervical spondylotic myelopathy Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7670 , vital:54741 , https://doi.org/10.1186/s40001-021-00483-0
- Description: Background: Here, we report an atypical HIV-vacuolar myelopathy and search the available medical literature about atypical presentations of human immunodefciency virus associate vacuolar myelopathy (HIV-VM) and immunoglobu‑ lin therapy response. Case: A 26-year-old lady who was 4 weeks postpartum presented to us with acute faccid quadriparesis, with no sen‑ sory level. Extensive workup ruled out other causes of myelopathy. She developed a stage 3 acute kidney injury, and MRI showed difuse cord atrophy involving the lower cervical and thoracic cord. The patient received IV-immunoglob‑ ulin, ARVs, and supportive therapy with inadequate response. Unfortunately, she developed nosocomial pneumonia and died. Discussion: In HIV-VM, there is spinal cord atrophy, which mainly involves the thoracic cord. In our case, this patho‑ logical process also afected the spinal cord’s cervical region, leading to faccid tetraplegia, with high CD4 level, with‑ out response to the treatment, including intravenous immunoglobulin. Keynotes: Vacuolar myelopathy, HIV, Immunoglobulin therapy, faccid tetraplegia, hypokalaemia. Renal failure. Keywords: Human immunodefciency virus, Associated lesions of the nervous system, Human immunodefciency virus-associated myelopathy, Intravenous immunoglobulin administration, Case report, HIV-vacuolar myelopathy
- Full Text:
- Date Issued: 2021-06
- Authors: Mongezi, Tau , Sibi, Joseph , Jerry, George , Lourdes de Fátima, Ibañez Valdés , Tozama, Dubula , Humberto, Foyaca Sibat
- Date: 2021-06
- Subjects: South Africa HIV (Viruses) Cervical spondylotic myelopathy Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7670 , vital:54741 , https://doi.org/10.1186/s40001-021-00483-0
- Description: Background: Here, we report an atypical HIV-vacuolar myelopathy and search the available medical literature about atypical presentations of human immunodefciency virus associate vacuolar myelopathy (HIV-VM) and immunoglobu‑ lin therapy response. Case: A 26-year-old lady who was 4 weeks postpartum presented to us with acute faccid quadriparesis, with no sen‑ sory level. Extensive workup ruled out other causes of myelopathy. She developed a stage 3 acute kidney injury, and MRI showed difuse cord atrophy involving the lower cervical and thoracic cord. The patient received IV-immunoglob‑ ulin, ARVs, and supportive therapy with inadequate response. Unfortunately, she developed nosocomial pneumonia and died. Discussion: In HIV-VM, there is spinal cord atrophy, which mainly involves the thoracic cord. In our case, this patho‑ logical process also afected the spinal cord’s cervical region, leading to faccid tetraplegia, with high CD4 level, with‑ out response to the treatment, including intravenous immunoglobulin. Keynotes: Vacuolar myelopathy, HIV, Immunoglobulin therapy, faccid tetraplegia, hypokalaemia. Renal failure. Keywords: Human immunodefciency virus, Associated lesions of the nervous system, Human immunodefciency virus-associated myelopathy, Intravenous immunoglobulin administration, Case report, HIV-vacuolar myelopathy
- Full Text:
- Date Issued: 2021-06
The reproductive performance, demography and spatial ecology of an extralimital white rhinoceros population
- Authors: Truter, Anja
- Date: 2021-04
- Subjects: White rhinoceros -- South Africa -- Eastern Cape , White rhinoceros -- Effect of poaching on -- South Africa -- Eastern Cape , White rhinoceros -- South Africa -- Eastern Cape -- Reproduction , White rhinoceros -- Dispersal -- South Africa -- Eastern Cape , White rhinoceros -- Food -- South Africa -- Eastern Cape , White rhinoceros -- Behavior -- South Africa -- Eastern Cape , Spatial ecology -- South Africa -- Eastern Cape , Animal populations -- South Africa -- Eastern Cape , Endangered species -- South Africa -- Eastern Cape , Spatial behavior in animals -- South Africa -- Eastern Cape , Shamwari Game Reserve (South Africa)
- Language: English
- Type: thesis , text , Master , MSc
- Identifier: http://hdl.handle.net/10962/177975 , vital:42895
- Description: The white rhinoceros (Ceratotherium simum) (hereafter rhino) is under threat of becoming extinct due to continued poaching for its horns. In South Africa and elsewhere in Africa private landowners have, over the last few decades, contributed to the conservation of various species, including rhinos, even in areas where they have not occurred historically (i.e., where they are extralimital). Unfortunately, very few studies have investigated the conservation contribution of extralimital white rhinos on private reserves to the overall meta-population and/or their reproductive performance. The first aim of my study was therefore to determine whether or not the white rhinos introduced to a private game reserve in the Eastern Cape Province in 1992 have been successful from a reproductive perspective. I calculated inter-calving intervals, age at first calving, conception period, sex ratio, fecundity and fertility rates for white rhinos over this 28-year period. The average annual population growth rate for the rhinos was 10%, which is higher than the recommended 5% by the Rhino Management Group. Trends in density-dependent parameters such as age at first calving and inter-calving intervals also indicated that my study population is still well below carrying capacity for white rhinos and is contributing positively to white rhino conservation in South Africa. The second aim of my study was to investigate home range size and vegetation preferences of white rhinos. Home ranges were mostly larger for all age groups compared to rhinos in their native range. Previously cultivated lands (dominated by several grass species) were preferred by all rhino age groups. The rehabilitation of these previous agricultural-based pastures has likely contributed to the successful introduction of the white rhino as an extralimital megaherbivore in the Eastern Cape. I conclude that although extralimital white rhino populations in the Eastern Cape can be successful from a reproductive perspective, their potential impact on the indigenous biodiversity of the region should be a key future research priority. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Truter, Anja
- Date: 2021-04
- Subjects: White rhinoceros -- South Africa -- Eastern Cape , White rhinoceros -- Effect of poaching on -- South Africa -- Eastern Cape , White rhinoceros -- South Africa -- Eastern Cape -- Reproduction , White rhinoceros -- Dispersal -- South Africa -- Eastern Cape , White rhinoceros -- Food -- South Africa -- Eastern Cape , White rhinoceros -- Behavior -- South Africa -- Eastern Cape , Spatial ecology -- South Africa -- Eastern Cape , Animal populations -- South Africa -- Eastern Cape , Endangered species -- South Africa -- Eastern Cape , Spatial behavior in animals -- South Africa -- Eastern Cape , Shamwari Game Reserve (South Africa)
- Language: English
- Type: thesis , text , Master , MSc
- Identifier: http://hdl.handle.net/10962/177975 , vital:42895
- Description: The white rhinoceros (Ceratotherium simum) (hereafter rhino) is under threat of becoming extinct due to continued poaching for its horns. In South Africa and elsewhere in Africa private landowners have, over the last few decades, contributed to the conservation of various species, including rhinos, even in areas where they have not occurred historically (i.e., where they are extralimital). Unfortunately, very few studies have investigated the conservation contribution of extralimital white rhinos on private reserves to the overall meta-population and/or their reproductive performance. The first aim of my study was therefore to determine whether or not the white rhinos introduced to a private game reserve in the Eastern Cape Province in 1992 have been successful from a reproductive perspective. I calculated inter-calving intervals, age at first calving, conception period, sex ratio, fecundity and fertility rates for white rhinos over this 28-year period. The average annual population growth rate for the rhinos was 10%, which is higher than the recommended 5% by the Rhino Management Group. Trends in density-dependent parameters such as age at first calving and inter-calving intervals also indicated that my study population is still well below carrying capacity for white rhinos and is contributing positively to white rhino conservation in South Africa. The second aim of my study was to investigate home range size and vegetation preferences of white rhinos. Home ranges were mostly larger for all age groups compared to rhinos in their native range. Previously cultivated lands (dominated by several grass species) were preferred by all rhino age groups. The rehabilitation of these previous agricultural-based pastures has likely contributed to the successful introduction of the white rhino as an extralimital megaherbivore in the Eastern Cape. I conclude that although extralimital white rhino populations in the Eastern Cape can be successful from a reproductive perspective, their potential impact on the indigenous biodiversity of the region should be a key future research priority. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-04
Features of Graduate Underemployment in South Africa: A Study in Mthatha, Eastern Cape Province
- Mayekiso, Cwenga, Obioha, Emeka E
- Authors: Mayekiso, Cwenga , Obioha, Emeka E
- Date: 2021-03
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7451 , vital:53966 , https://journals.co.za/doi/full/10.31920/2634-3649/2021/v11n1a8
- Description: This paper articulates the patterns and feel of graduate underemployment in Mthatha, a South African town in the Eastern Cape Province. Foregrounded on Peter Blua’s Social Exchange Theory, this study adopted a quantitative approach. A sample of 60 respondents was drawn from underemployed graduate population through a combination of stratified and random sampling techniques. Data collected from survey (questionnaire) were analysed with appropriate tools in the Statistical Package for the Social Sciences. The study found that majority of underemployed graduates are between 21 and 25 years of age, married, hold bachelor’s degrees in Social Sciences. Gender, qualification type and level of qualification have no significant influence on determining underemployed graduates’ choice of occupation as single and combined variables or factors. While only very few (5%) of the underemployed graduates are never happy at work, femaleness, older graduates, Africans, higher qualification, higher basic salary and longer years of underemployment best predict happiness at work, although not at significant level, except for basic salary. A majority of graduates (73.3%) do sometimes consider leaving their current jobs, even when there are no alternatives. This is influenced by maleness, older graduates, being Whites, higher qualification, lower basic salary and lower years of underemployment. Lack of networking was found to be the most important factor in graduate underemployment, followed by lack of experience and gender not being significant. This study recommends policy intervention by state, where there is legislation that provides for entry level jobs that may not require previous experience. Also, there should be another legislation that protects the underemployed through salary regulation and incentivising of employers that engage workers in such capacity. Keywords: Underemployment, Youth, Graduates, South Africa.
- Full Text:
- Date Issued: 2021-03
- Authors: Mayekiso, Cwenga , Obioha, Emeka E
- Date: 2021-03
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7451 , vital:53966 , https://journals.co.za/doi/full/10.31920/2634-3649/2021/v11n1a8
- Description: This paper articulates the patterns and feel of graduate underemployment in Mthatha, a South African town in the Eastern Cape Province. Foregrounded on Peter Blua’s Social Exchange Theory, this study adopted a quantitative approach. A sample of 60 respondents was drawn from underemployed graduate population through a combination of stratified and random sampling techniques. Data collected from survey (questionnaire) were analysed with appropriate tools in the Statistical Package for the Social Sciences. The study found that majority of underemployed graduates are between 21 and 25 years of age, married, hold bachelor’s degrees in Social Sciences. Gender, qualification type and level of qualification have no significant influence on determining underemployed graduates’ choice of occupation as single and combined variables or factors. While only very few (5%) of the underemployed graduates are never happy at work, femaleness, older graduates, Africans, higher qualification, higher basic salary and longer years of underemployment best predict happiness at work, although not at significant level, except for basic salary. A majority of graduates (73.3%) do sometimes consider leaving their current jobs, even when there are no alternatives. This is influenced by maleness, older graduates, being Whites, higher qualification, lower basic salary and lower years of underemployment. Lack of networking was found to be the most important factor in graduate underemployment, followed by lack of experience and gender not being significant. This study recommends policy intervention by state, where there is legislation that provides for entry level jobs that may not require previous experience. Also, there should be another legislation that protects the underemployed through salary regulation and incentivising of employers that engage workers in such capacity. Keywords: Underemployment, Youth, Graduates, South Africa.
- Full Text:
- Date Issued: 2021-03
5-Fu inclusion complex capped gold nanoparticles for breast cancer therapy
- Lakkakula, Jaya R, Krause, Rui W M, Divakaran, Deepika, Barage, Sagar, Srivastava, Rohit
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
- Authors: Lakkakula, Jaya R , Krause, Rui W M , Divakaran, Deepika , Barage, Sagar , Srivastava, Rohit
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/191713 , vital:45150 , xlink:href="https://doi.org/10.1016/j.molliq.2021.117262"
- Description: We have attempted to prolong the circulation time and increase the solubility of 5-Fluorouracil by complexing it with cyclodextrin and then further conjugating onto the gold nanoparticle to form 5Fu ICAu. The 1H NMR and molecular docking studies suggested that 5-Fu was included within the 2HP-β-CD cavity and H-5 proton probably serves as the binding site for stabilization of the inclusion complex. The 5Fu-ICAu showed higher cell inhibition rate when studied on MDA-MB-231 and MCF-7 breast cancer cell lines due to the enhanced permeability and retention (EPR) effect by allowing the selective accumulation of nanoparticles at tumor site. This unique system can serve as a novel nanocarrier for delivery of hydrophobic drugs.
- Full Text:
- Date Issued: 2021
A case for ethical frameworks to enhance mobile government implementation at South African municipalities
- Makwembere, Sandra, Garidzira, Rufaro
- Authors: Makwembere, Sandra , Garidzira, Rufaro
- Date: 2021
- Subjects: Government Ethics Technology and state Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7170 , vital:53081 , xlink:href="https://doi.org/10.4102/td.v17i1.826"
- Description: Interest in mobile government (m-government) is growing globally. Mobile government refers to the use of wireless and mobile technologies to deliver services to citizens, businesses, employees and other government entities. Presently, technological advancements take place despite questions on whether the existing policy and regulatory frameworks are suitable to regulate the effects of m-government. With m-government, municipal operations take place in virtual spaces where the consequences of such operations are still largely unknown and the frameworks that are apt to minimise any long-term effects on society are yet to be defined. This conceptual article suggests that ethical frameworks should be encouraged as part of mobile government implementation in municipalities to encourage reflective municipal practices and to improve judgement and behaviour in m-government decision-making. It contributes to debates on approaches to comprehensively support and guide mobile government towards positive municipal service delivery outcomes. Keywords: m-government; ethics; ethical frameworks; municipal service delivery; e-government; mobile technology
- Full Text:
- Date Issued: 2021
- Authors: Makwembere, Sandra , Garidzira, Rufaro
- Date: 2021
- Subjects: Government Ethics Technology and state Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7170 , vital:53081 , xlink:href="https://doi.org/10.4102/td.v17i1.826"
- Description: Interest in mobile government (m-government) is growing globally. Mobile government refers to the use of wireless and mobile technologies to deliver services to citizens, businesses, employees and other government entities. Presently, technological advancements take place despite questions on whether the existing policy and regulatory frameworks are suitable to regulate the effects of m-government. With m-government, municipal operations take place in virtual spaces where the consequences of such operations are still largely unknown and the frameworks that are apt to minimise any long-term effects on society are yet to be defined. This conceptual article suggests that ethical frameworks should be encouraged as part of mobile government implementation in municipalities to encourage reflective municipal practices and to improve judgement and behaviour in m-government decision-making. It contributes to debates on approaches to comprehensively support and guide mobile government towards positive municipal service delivery outcomes. Keywords: m-government; ethics; ethical frameworks; municipal service delivery; e-government; mobile technology
- Full Text:
- Date Issued: 2021
A critical appraisal of the recruitment and selection process of the Public Protector in South Africa
- Bazana, Sandiso, Reddy, Tayra
- Authors: Bazana, Sandiso , Reddy, Tayra
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453707 , vital:75279 , xlink:href=" https://journals.co.za/doi/full/10.4102/sajhrm.v19i0.1207"
- Description: Orientation: The process of recruitment and selection the Public Protector (PP) needs to ensure that the most ‘fit and proper’ candidate is appointed. The process needs critical scrutiny for such a fit and proper candidate to be selected. Research motivation: South Africa’s superior courts, including the Constitutional court have recently (in 2019) labelled the current Public Protector; dishonest and Incompetent in carrying out the duties of the PP office. Research purpose: This article critically appraises the recent process that culminated in the appointment of Ms Busisiwe Mkhwebane as the fourth Public Protector in the democratic South Africa.
- Full Text:
- Date Issued: 2021
- Authors: Bazana, Sandiso , Reddy, Tayra
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453707 , vital:75279 , xlink:href=" https://journals.co.za/doi/full/10.4102/sajhrm.v19i0.1207"
- Description: Orientation: The process of recruitment and selection the Public Protector (PP) needs to ensure that the most ‘fit and proper’ candidate is appointed. The process needs critical scrutiny for such a fit and proper candidate to be selected. Research motivation: South Africa’s superior courts, including the Constitutional court have recently (in 2019) labelled the current Public Protector; dishonest and Incompetent in carrying out the duties of the PP office. Research purpose: This article critically appraises the recent process that culminated in the appointment of Ms Busisiwe Mkhwebane as the fourth Public Protector in the democratic South Africa.
- Full Text:
- Date Issued: 2021
A Critical Review of Environmental Governance, Land Restitution, and Tourism in Protected Areas
- Authors: Ramukumba, Takalani
- Date: 2021
- Subjects: Tourism Land use Environmental protection Wildlife conservation Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7029 , vital:52756 , xlink:href=":https://doi.org/10.46222/ajhtl.19770720.200"
- Description: Natural areas, when protected, conserve the natural environment and function as social spaces in which tourism brings increased income, employment, and financial support for conservation. The inclusion of local community members in the planning and management of protected areas has been on the rise since the early 1900s. Tourism has been advocated as a strategy that can help in achieving economic development, especially in rural areas. However, governance issues and potential negative impacts of tourism development have been under inspection. Conservation efforts in Southern Africa especially in the late 1800s and early 1900s had negative impacts on the local communities since this led to many communities being displaced or having limited access to these protected areas. This has seen the need for ways and efforts to get local community members' despondency and attitudes towards protected areas change such that in the 20th century, there were efforts to use conservation models that included community members in the decision-making and benefit-sharing process to garner their support for protected areas. This paper reviews literature on environmental governance, land restitution in protected areas, tourism in protected areas, co-management, and the importance of community participation. These concepts are reviewed using Manyeleti Game Reserve as a case study. Keywords: Tourism, land restitution, environmental governance, wildlife resources, and stakeholder participation
- Full Text:
- Date Issued: 2021
- Authors: Ramukumba, Takalani
- Date: 2021
- Subjects: Tourism Land use Environmental protection Wildlife conservation Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7029 , vital:52756 , xlink:href=":https://doi.org/10.46222/ajhtl.19770720.200"
- Description: Natural areas, when protected, conserve the natural environment and function as social spaces in which tourism brings increased income, employment, and financial support for conservation. The inclusion of local community members in the planning and management of protected areas has been on the rise since the early 1900s. Tourism has been advocated as a strategy that can help in achieving economic development, especially in rural areas. However, governance issues and potential negative impacts of tourism development have been under inspection. Conservation efforts in Southern Africa especially in the late 1800s and early 1900s had negative impacts on the local communities since this led to many communities being displaced or having limited access to these protected areas. This has seen the need for ways and efforts to get local community members' despondency and attitudes towards protected areas change such that in the 20th century, there were efforts to use conservation models that included community members in the decision-making and benefit-sharing process to garner their support for protected areas. This paper reviews literature on environmental governance, land restitution in protected areas, tourism in protected areas, co-management, and the importance of community participation. These concepts are reviewed using Manyeleti Game Reserve as a case study. Keywords: Tourism, land restitution, environmental governance, wildlife resources, and stakeholder participation
- Full Text:
- Date Issued: 2021
A decade of biological control of Parthenium hysterophorus L.(Asteraceae) in South Africa reviewed: introduction of insect agents and their status
- Strathie, L W, Cowie, Blair W, McConnachie, Andrew J, Chidawanyika, Frank, Musedeli, Jufter N, Sambo, SMC, Magoso, EX, Gareeb, M
- Authors: Strathie, L W , Cowie, Blair W , McConnachie, Andrew J , Chidawanyika, Frank , Musedeli, Jufter N , Sambo, SMC , Magoso, EX , Gareeb, M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416795 , vital:71386 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a11"
- Description: The annual herb, Parthenium hysterophorus L. (Asteraceae: Heliantheae) is a severe terrestrial invader globally. Infestations reduce crop yield, limit available grazing, hinder conservation efforts, and affect human and animal health in Africa, Asia and Australia, and on associated islands. Due to the impact and threat of further invasion of P. hysterophorus, a biological control (biocontrol) programme was initiated in 2003 in South Africa. This review discusses the research and implementation activities undertaken on the insect agents from 2011 to 2020. During this period, the stem-boring weevil Listronotus setosipennis Hustache (Coleoptera: Curculionidae), leaf-feeding beetle Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) and seed-feeding weevil Smicronyx lutulentus Dietz (Coleoptera: Curculionidae), were found to be host specific and approved for release. Releases of mass-reared insect agents have been concentrated particularly in north-eastern South Africa, where P. hysterophorus infestations are most prolific. Post-release monitoring studies indicated localised establishment and impact of L. setosipennis and S. lutulentus. Listronotus setosipennis persisted through severe drought conditions, and although it disperses slowly, larval feeding is structurally damaging. Establishment of S. lutulentus is improving, reducing seed production where it is established. Zygogramma bicolorata resulted in defoliation at a few sites, but establishment has been poor and the beetle has been absent since 2019. Although a combination of fungal and insect agents were demonstrated to reduce P. hysterophorus, additional natural enemies could improve control. Consequently, the stem-galling moth Epiblema strenuana Walker (Lepidoptera: Tortricidae) and root-crown boring moth Carmenta sp. nr. ithacae (Beutenmüller) (Lepidoptera: Sesiidae) remain under evaluation. The management of P. hysterophorus in South Africa has been guided by the development of a national strategy, which incorporates multiple management methods, including biocontrol. International collaborations have intensified as a growing number of countries begin to utilize biocontrol to manage P. hysterophorus. Despite the progress towards biocontrol of P. hysterophorus during this period, increased utilisation of approved agents and the introduction of additional agents are necessary to achieve greater control.
- Full Text:
- Date Issued: 2021
- Authors: Strathie, L W , Cowie, Blair W , McConnachie, Andrew J , Chidawanyika, Frank , Musedeli, Jufter N , Sambo, SMC , Magoso, EX , Gareeb, M
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416795 , vital:71386 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a11"
- Description: The annual herb, Parthenium hysterophorus L. (Asteraceae: Heliantheae) is a severe terrestrial invader globally. Infestations reduce crop yield, limit available grazing, hinder conservation efforts, and affect human and animal health in Africa, Asia and Australia, and on associated islands. Due to the impact and threat of further invasion of P. hysterophorus, a biological control (biocontrol) programme was initiated in 2003 in South Africa. This review discusses the research and implementation activities undertaken on the insect agents from 2011 to 2020. During this period, the stem-boring weevil Listronotus setosipennis Hustache (Coleoptera: Curculionidae), leaf-feeding beetle Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) and seed-feeding weevil Smicronyx lutulentus Dietz (Coleoptera: Curculionidae), were found to be host specific and approved for release. Releases of mass-reared insect agents have been concentrated particularly in north-eastern South Africa, where P. hysterophorus infestations are most prolific. Post-release monitoring studies indicated localised establishment and impact of L. setosipennis and S. lutulentus. Listronotus setosipennis persisted through severe drought conditions, and although it disperses slowly, larval feeding is structurally damaging. Establishment of S. lutulentus is improving, reducing seed production where it is established. Zygogramma bicolorata resulted in defoliation at a few sites, but establishment has been poor and the beetle has been absent since 2019. Although a combination of fungal and insect agents were demonstrated to reduce P. hysterophorus, additional natural enemies could improve control. Consequently, the stem-galling moth Epiblema strenuana Walker (Lepidoptera: Tortricidae) and root-crown boring moth Carmenta sp. nr. ithacae (Beutenmüller) (Lepidoptera: Sesiidae) remain under evaluation. The management of P. hysterophorus in South Africa has been guided by the development of a national strategy, which incorporates multiple management methods, including biocontrol. International collaborations have intensified as a growing number of countries begin to utilize biocontrol to manage P. hysterophorus. Despite the progress towards biocontrol of P. hysterophorus during this period, increased utilisation of approved agents and the introduction of additional agents are necessary to achieve greater control.
- Full Text:
- Date Issued: 2021
A framework to test South Africa’s readiness for the fourth industrial revolution
- Olaitan, Olutoyin O., Issah, Moshood, Wayi, Ntombovuyo
- Authors: Olaitan, Olutoyin O. , Issah, Moshood , Wayi, Ntombovuyo
- Date: 2021
- Subjects: Industry 4.0 Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7153 , vital:53072 , xlink:href=" https://doi.org/10.4102/sajim.v23i1.1284"
- Description: Background: The fourth industrial revolution (4IR) is being touted as having the capacity to lift South Africa out of the challenges of poverty, unemployment and inequitable distribution of wealth. However, the state of the country’s readiness for the enabling technologies of the 4IR is in question. Objective: This article sought to investigate South Africa’s state of readiness for the technologies that enable the 4IR. The article proposed a framework which can be used to measure the country’s level of preparedness and implement the necessary processes to move the country into the 4IR era. Method: A detailed analysis of literature was carried out on the current and futuristic technologies employed by developed countries as they moved towards the 4IR. The fit – viability and the task – technology theories were employed to propose a framework to government for measuring its state of readiness for the 4IR in South Africa. Results: Based on findings from the literature study, the article proposed the 4IR readiness framework for government to measure and subsequently plans its response to the advent of 4IR technologies in the country. Conclusion: The framework revealed that South Africa has low technological capability, plummeting economic complexity and a fall in digital technological readiness. There is also a dearth of skilled workforce and technological infrastructure. It was recommended that government should focus on building and strengthening the resilience of both public and private institutions, investment in relevant 4IR education, infrastructural improvement, and promulgation and enforcement of legal framework to ensure security and privacy of data. Keywords: 4IR; task – technology; fit – viability; digital technology readiness; economic complexity
- Full Text:
- Date Issued: 2021
- Authors: Olaitan, Olutoyin O. , Issah, Moshood , Wayi, Ntombovuyo
- Date: 2021
- Subjects: Industry 4.0 Article
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/7153 , vital:53072 , xlink:href=" https://doi.org/10.4102/sajim.v23i1.1284"
- Description: Background: The fourth industrial revolution (4IR) is being touted as having the capacity to lift South Africa out of the challenges of poverty, unemployment and inequitable distribution of wealth. However, the state of the country’s readiness for the enabling technologies of the 4IR is in question. Objective: This article sought to investigate South Africa’s state of readiness for the technologies that enable the 4IR. The article proposed a framework which can be used to measure the country’s level of preparedness and implement the necessary processes to move the country into the 4IR era. Method: A detailed analysis of literature was carried out on the current and futuristic technologies employed by developed countries as they moved towards the 4IR. The fit – viability and the task – technology theories were employed to propose a framework to government for measuring its state of readiness for the 4IR in South Africa. Results: Based on findings from the literature study, the article proposed the 4IR readiness framework for government to measure and subsequently plans its response to the advent of 4IR technologies in the country. Conclusion: The framework revealed that South Africa has low technological capability, plummeting economic complexity and a fall in digital technological readiness. There is also a dearth of skilled workforce and technological infrastructure. It was recommended that government should focus on building and strengthening the resilience of both public and private institutions, investment in relevant 4IR education, infrastructural improvement, and promulgation and enforcement of legal framework to ensure security and privacy of data. Keywords: 4IR; task – technology; fit – viability; digital technology readiness; economic complexity
- Full Text:
- Date Issued: 2021
A heavy-atom-free π-extended N-confused porphyrin as a photosensitizer for photodynamic therapy
- Babu, Balaji, Mack, John, Nyokong, Tebello
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185909 , vital:44447 , xlink:href="https://doi.org/10.1039/d1nj00112d"
- Description: The synthesis and characterization of a novel 1,3-diethyl-2-thiobarbituric-acid-substituted N-confused porphyrin (NCP-TB) is reported, along with a study of its photodynamic activity against MCF-7 cells using 530 (110 mW cm−2) and 660 nm (280 mW cm−2) Thorlabs light-emitting diodes for 30 min. The singlet oxygen quantum yield for NCP-TB is 0.38 compared to 0.23 for the parent unsubstituted N-confused porphyrin (NCP) due to the presence of a sulfur atom. NCP-TB exhibits enhanced PDT activity compared to NCP at both wavelengths. A significantly lower IC50 value of 5.2 μM was obtained at 530 nm (14.7 μM at 660 nm) despite a smaller light dose, due to a large red shift of the intense B band into the green region of the spectrum. 2′,7′-Dichlorofluorescein diacetate (DCFDA) assays demonstrate that there is intracellular generation of reactive oxygen species upon exposure to light.
- Full Text:
- Date Issued: 2021
- Authors: Babu, Balaji , Mack, John , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185909 , vital:44447 , xlink:href="https://doi.org/10.1039/d1nj00112d"
- Description: The synthesis and characterization of a novel 1,3-diethyl-2-thiobarbituric-acid-substituted N-confused porphyrin (NCP-TB) is reported, along with a study of its photodynamic activity against MCF-7 cells using 530 (110 mW cm−2) and 660 nm (280 mW cm−2) Thorlabs light-emitting diodes for 30 min. The singlet oxygen quantum yield for NCP-TB is 0.38 compared to 0.23 for the parent unsubstituted N-confused porphyrin (NCP) due to the presence of a sulfur atom. NCP-TB exhibits enhanced PDT activity compared to NCP at both wavelengths. A significantly lower IC50 value of 5.2 μM was obtained at 530 nm (14.7 μM at 660 nm) despite a smaller light dose, due to a large red shift of the intense B band into the green region of the spectrum. 2′,7′-Dichlorofluorescein diacetate (DCFDA) assays demonstrate that there is intracellular generation of reactive oxygen species upon exposure to light.
- Full Text:
- Date Issued: 2021
A new species of Buyisa Distant, 1907 (Hemiptera Cicadidae Cicadettinae Cicadettini) from South Africa
- Sanborn, Allen F, Villet, Martin H
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441318 , vital:73877 , https://doi.org/10.4289/0013-8797.123.1.199
- Description: A new species of the cicada genus Buyisa Distant, 1907 is described from South Africa for an undetermined species referenced in the literature. Buyisa eccaensis new species is described and illustrated and notes on its biology are provided. A key to the officially described species of Buyisa is also included.
- Full Text:
- Date Issued: 2021
- Authors: Sanborn, Allen F , Villet, Martin H
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441318 , vital:73877 , https://doi.org/10.4289/0013-8797.123.1.199
- Description: A new species of the cicada genus Buyisa Distant, 1907 is described from South Africa for an undetermined species referenced in the literature. Buyisa eccaensis new species is described and illustrated and notes on its biology are provided. A key to the officially described species of Buyisa is also included.
- Full Text:
- Date Issued: 2021
A new species of red toad, Schismaderma Smith, 1849 (Anura: Bufonidae), from central Angola
- Baptista, Ninda L, Pinto, Pedro V, Keates, Chad, Edwards, Shelley, Rödel, Mark-Oliver, Conradie, Werner C
- Authors: Baptista, Ninda L , Pinto, Pedro V , Keates, Chad , Edwards, Shelley , Rödel, Mark-Oliver , Conradie, Werner C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461462 , vital:76204 , xlink:href="https://www.biotaxa.org/Zootaxa/article/view/zootaxa.5081.3.1"
- Description: A new species of red toad, from the previously monotypic genus Schismaderma, is described. The new species was found in Malanje Province, and seems endemic to central Angola, occurring approximately 500 km west of the closest known records of Schismaderma carens. Unusual adult colouration and geographical distance to remaining S. carens populations suggested specific differentiation. In an integrative approach, we compared the red toads from central Angola with S. carens from across the entire range, including molecular data, morphology of adults and tadpoles, and male advertisement calls. Phylogenetic analysis based on mitochondrial (12S, 16S, COI) and nuclear (CXCR4, RAG1) markers, retrieved the Angolan clade as monophyletic, and revealed intra-specific substructuring among the remaining Schismaderma. Genetic distances supported specific differentiation of the central Angolan material compared with other S. carens. Adults from the new Angolan species have bolder ventral patterning and smaller body size than S. carens. No obvious differences were detected between the tadpoles and the advertisement calls of the two Schismaderma species. This discovery adds to the knowledge of the herpetofauna of the Angolan Miombo woodlands, a poorly understood ecoregion, and likely more biodiverse than previously assumed. The result of past river basin dynamics in central Angola likely led to the evolution of this new species of Schismaderma.
- Full Text:
- Date Issued: 2021
- Authors: Baptista, Ninda L , Pinto, Pedro V , Keates, Chad , Edwards, Shelley , Rödel, Mark-Oliver , Conradie, Werner C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/461462 , vital:76204 , xlink:href="https://www.biotaxa.org/Zootaxa/article/view/zootaxa.5081.3.1"
- Description: A new species of red toad, from the previously monotypic genus Schismaderma, is described. The new species was found in Malanje Province, and seems endemic to central Angola, occurring approximately 500 km west of the closest known records of Schismaderma carens. Unusual adult colouration and geographical distance to remaining S. carens populations suggested specific differentiation. In an integrative approach, we compared the red toads from central Angola with S. carens from across the entire range, including molecular data, morphology of adults and tadpoles, and male advertisement calls. Phylogenetic analysis based on mitochondrial (12S, 16S, COI) and nuclear (CXCR4, RAG1) markers, retrieved the Angolan clade as monophyletic, and revealed intra-specific substructuring among the remaining Schismaderma. Genetic distances supported specific differentiation of the central Angolan material compared with other S. carens. Adults from the new Angolan species have bolder ventral patterning and smaller body size than S. carens. No obvious differences were detected between the tadpoles and the advertisement calls of the two Schismaderma species. This discovery adds to the knowledge of the herpetofauna of the Angolan Miombo woodlands, a poorly understood ecoregion, and likely more biodiverse than previously assumed. The result of past river basin dynamics in central Angola likely led to the evolution of this new species of Schismaderma.
- Full Text:
- Date Issued: 2021
A population genetics study of Pale-winged Starlings, Onychognathus nabouroup, using novel microsatellite markers
- Munshi, Naadhira, Symes, Craig, Maayer, Pieter de, Craig, Adrian J F K, Henry, Laurence, Hausberger, Martine, Mollett, Jean
- Authors: Munshi, Naadhira , Symes, Craig , Maayer, Pieter de , Craig, Adrian J F K , Henry, Laurence , Hausberger, Martine , Mollett, Jean
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448718 , vital:74754 , https://www.ajol.info/index.php/scopus/article/view/211291
- Description: Recent research into starling species has revealed the existence of vocal social markers and a link between song temporal structuring and social organisation. The aim of the present study was to develop a genetic tool for understanding the population structuring and behaviour (social/parental transmission) and mating in Pale-winged Starlings (Onychognathus nabouroup), a songbird which is found in arid areas of southern Africa. Using next-generation sequencing, microsatellite markers comprising six dinucleotides, eighteen trinucleotides and twenty-four tetra-nucleotides specific to the Pale-winged Starling were isolated and developed. A total of 77 birds were sampled from the Augrabies Falls Nature Reserve in South Africa (n= 53) and the Ai Ais-Richtersveld Transfrontier Park resort in Namibia (n= 24), respectively. Fifteen polymorphic microsatellite markers were genotyped. The statistical programme STRUCTURE revealed four different genetic clusters within the two populations.
- Full Text:
- Date Issued: 2021
- Authors: Munshi, Naadhira , Symes, Craig , Maayer, Pieter de , Craig, Adrian J F K , Henry, Laurence , Hausberger, Martine , Mollett, Jean
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448718 , vital:74754 , https://www.ajol.info/index.php/scopus/article/view/211291
- Description: Recent research into starling species has revealed the existence of vocal social markers and a link between song temporal structuring and social organisation. The aim of the present study was to develop a genetic tool for understanding the population structuring and behaviour (social/parental transmission) and mating in Pale-winged Starlings (Onychognathus nabouroup), a songbird which is found in arid areas of southern Africa. Using next-generation sequencing, microsatellite markers comprising six dinucleotides, eighteen trinucleotides and twenty-four tetra-nucleotides specific to the Pale-winged Starling were isolated and developed. A total of 77 birds were sampled from the Augrabies Falls Nature Reserve in South Africa (n= 53) and the Ai Ais-Richtersveld Transfrontier Park resort in Namibia (n= 24), respectively. Fifteen polymorphic microsatellite markers were genotyped. The statistical programme STRUCTURE revealed four different genetic clusters within the two populations.
- Full Text:
- Date Issued: 2021
A review of the biocontrol programmes against aquatic weeds in South Africa
- Coetzee, Julie A, Bownes, Angela, Martin, Grant D, Miller, Benjamin E, Smith, Rosalie, Weyl, Philip S R, Hill, Martin P
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D , Miller, Benjamin E , Smith, Rosalie , Weyl, Philip S R , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406965 , vital:70326 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a18"
- Description: Biological control (biocontrol) against invasive macrophytes is one of the longest standing programmes in South Africa, initiated in the 1970s against water hyacinth, Pontederia crassipes Mart. (Pontederiaceae). Since then, 15 agent species (13 insects, one mite and one pathogen) have been released against six weeds, most of which are floating macrophytes, with excellent levels of success. The release of the water hyacinth planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae) in particular, has improved biocontrol prospects for water hyacinth since 2018. In the last decade, however, a new suite of submerged and rooted emergent invasive macrophytes has been targeted. The first release against a submerged macrophyte in South Africa, and the first release against Brazilian waterweed, Egeria densa Planch. (Hydrocharitaceae), anywhere in the world, was achieved with the release of a leafmining fly, Hydrellia egeriae Rodrigues-Júnior, Mathis and Hauser (Diptera: Ephydridae). Yellow flag, Iris pseudacorus L. (Iridaceae) and Mexican waterlily, Nymphaea mexicana Zucc. (Nymphaeaceae), have also been targeted for biocontrol for the first time worldwide, and are in the early stages of agent development. Post-release evaluations, long term monitoring and controlled experiments have highlighted the need for a more holistic approach to managing aquatic invasive plants in South Africa, whose presence is largely driven by eutrophication, resulting in regime shifts between floating and submerged invaded states.
- Full Text:
- Date Issued: 2021
- Authors: Coetzee, Julie A , Bownes, Angela , Martin, Grant D , Miller, Benjamin E , Smith, Rosalie , Weyl, Philip S R , Hill, Martin P
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406965 , vital:70326 , xlink:href="https://hdl.handle.net/10520/ejc-ento_v29_n3_a18"
- Description: Biological control (biocontrol) against invasive macrophytes is one of the longest standing programmes in South Africa, initiated in the 1970s against water hyacinth, Pontederia crassipes Mart. (Pontederiaceae). Since then, 15 agent species (13 insects, one mite and one pathogen) have been released against six weeds, most of which are floating macrophytes, with excellent levels of success. The release of the water hyacinth planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae) in particular, has improved biocontrol prospects for water hyacinth since 2018. In the last decade, however, a new suite of submerged and rooted emergent invasive macrophytes has been targeted. The first release against a submerged macrophyte in South Africa, and the first release against Brazilian waterweed, Egeria densa Planch. (Hydrocharitaceae), anywhere in the world, was achieved with the release of a leafmining fly, Hydrellia egeriae Rodrigues-Júnior, Mathis and Hauser (Diptera: Ephydridae). Yellow flag, Iris pseudacorus L. (Iridaceae) and Mexican waterlily, Nymphaea mexicana Zucc. (Nymphaeaceae), have also been targeted for biocontrol for the first time worldwide, and are in the early stages of agent development. Post-release evaluations, long term monitoring and controlled experiments have highlighted the need for a more holistic approach to managing aquatic invasive plants in South Africa, whose presence is largely driven by eutrophication, resulting in regime shifts between floating and submerged invaded states.
- Full Text:
- Date Issued: 2021
Accelerated implementations of the RIME for DDE calibration and source modelling
- Authors: Van Staden, Joshua
- Date: 2021
- Subjects: Radio astronomy , Radio inferometers , Radio inferometers -- Calibration , Radio astronomy -- Data processing , Radio inferometers -- Data processing , Radio inferometers -- Calibration -- Data processing
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/172422 , vital:42199
- Description: Second- and third-generation calibration methods filter out subtle effects in interferometer data, and therefore yield significantly higher dynamic ranges. The basis of these calibration techniques relies on building a model of the sky and corrupting it with models of the effects acting on the sources. The sensitivities of modern instruments call for more elaborate models to capture the level of detail that is required to achieve accurate calibration. This thesis implements two types of models to be used in for second- and third-generation calibration. The first model implemented is shapelets, which can be used to model radio source morphologies directly in uv space. The second model implemented is Zernike polynomials, which can be used to represent the primary beam of the antenna. We implement these models in the CODEX-AFRICANUS package and provide a set of unit tests for each model. Additionally, we compare our implementations against other methods of representing these objects and instrumental effects, namely NIFTY-GRIDDER against shapelets and a FITS-interpolation method against the Zernike polynomials. We find that to achieve sufficient accuracy, our implementation of the shapelet model has a higher runtime to that of the NIFTY-GRIDDER. However, the NIFTY-GRIDDER cannot simulate a component-based sky model while the shapelet model can. Additionally, the shapelet model is fully parametric, which allows for integration into a parameterised solver. We find that, while having a smaller memory footprint, our Zernike model has a greater computational complexity than that of the FITS-interpolated method. However, we find that the Zernike implementation has floating-point accuracy in its modelling, while the FITS-interpolated model loses some accuracy through the discretisation of the beam.
- Full Text:
- Date Issued: 2021
- Authors: Van Staden, Joshua
- Date: 2021
- Subjects: Radio astronomy , Radio inferometers , Radio inferometers -- Calibration , Radio astronomy -- Data processing , Radio inferometers -- Data processing , Radio inferometers -- Calibration -- Data processing
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/172422 , vital:42199
- Description: Second- and third-generation calibration methods filter out subtle effects in interferometer data, and therefore yield significantly higher dynamic ranges. The basis of these calibration techniques relies on building a model of the sky and corrupting it with models of the effects acting on the sources. The sensitivities of modern instruments call for more elaborate models to capture the level of detail that is required to achieve accurate calibration. This thesis implements two types of models to be used in for second- and third-generation calibration. The first model implemented is shapelets, which can be used to model radio source morphologies directly in uv space. The second model implemented is Zernike polynomials, which can be used to represent the primary beam of the antenna. We implement these models in the CODEX-AFRICANUS package and provide a set of unit tests for each model. Additionally, we compare our implementations against other methods of representing these objects and instrumental effects, namely NIFTY-GRIDDER against shapelets and a FITS-interpolation method against the Zernike polynomials. We find that to achieve sufficient accuracy, our implementation of the shapelet model has a higher runtime to that of the NIFTY-GRIDDER. However, the NIFTY-GRIDDER cannot simulate a component-based sky model while the shapelet model can. Additionally, the shapelet model is fully parametric, which allows for integration into a parameterised solver. We find that, while having a smaller memory footprint, our Zernike model has a greater computational complexity than that of the FITS-interpolated method. However, we find that the Zernike implementation has floating-point accuracy in its modelling, while the FITS-interpolated model loses some accuracy through the discretisation of the beam.
- Full Text:
- Date Issued: 2021
Adaptation and validation of a computerized neurocognitive battery in the Xhosa of South Africa
- Cobb, Scott J, Moore, Tyler M, Stein, Dan J, Pretorius, Adele, Zingela, Zukiswa, Nagdee, Mohammed, Ngqengelele, Linda, Campbell, Megan M, Sibeko, Goodman, King, Mary C, McClellan, Jon M, Port, Allison M, Jackson, Chad, Ruparel, Kosha, Susser, Ezra, Gur, Ruben C
- Authors: Cobb, Scott J , Moore, Tyler M , Stein, Dan J , Pretorius, Adele , Zingela, Zukiswa , Nagdee, Mohammed , Ngqengelele, Linda , Campbell, Megan M , Sibeko, Goodman , King, Mary C , McClellan, Jon M , Port, Allison M , Jackson, Chad , Ruparel, Kosha , Susser, Ezra , Gur, Ruben C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302439 , vital:58196 , xlink:href="https://doi.org/10.1037/neu0000742"
- Description: Objective: Large-scale studies have revolutionized biomedical research, and neurocognitive tests can help elucidate the biological basis of neuropsychiatric diseases. However, studies have predominantly been conducted in Western settings. We describe the development and validation of a computerized battery (PennCNB) with the Xhosa population of South Africa. Method: Individuals with schizophrenia (n = 525) and a normative comparison group (n = 744) were balanced on age, sex, education, and region. Participants provided blood samples, were assessed psychiatrically, and were administered a PennCNB translation to isiXhosa, including measures of executive functions, episodic memory, complex cognition, social cognition, and sensorimotor speed. Feasibility was examined with test completion rates and input from administrators, and psychometric structural validity and associations with clinical and demographic characteristics were examined. Results: Tests were well tolerated by participants, as >87% had one (or fewer) test missing. Results suggested a similar factor structure to prior PennCNB studies in Western contexts, and expected age and sex effects were apparent. Furthermore, a similar profile of schizophrenia was observed, with neurocognitive deficits most pronounced for executive functions, especially attention, as well as memory, social cognition, and motor speed relative to complex cognition and sensorimotor speed. Conclusions: Results support the feasibility of implementing a culturally adapted computerized neurocognitive battery in sub-Saharan African settings and provide evidence supporting the concurrent validity of the translated instrument. Thus, the PennCNB is implementable on a large scale in non-Western contexts, shows expected factor structure, and can detect cognitive deficits associated with neuropsychiatric disorders. Obtaining valid measures of cognition by nonspecialized proctors is especially suitable in resource-limited settings, where traditional testing is prohibitive. Future work should establish normative standards, test–retest reliability, and sensitivity to treatment.
- Full Text:
- Date Issued: 2021
- Authors: Cobb, Scott J , Moore, Tyler M , Stein, Dan J , Pretorius, Adele , Zingela, Zukiswa , Nagdee, Mohammed , Ngqengelele, Linda , Campbell, Megan M , Sibeko, Goodman , King, Mary C , McClellan, Jon M , Port, Allison M , Jackson, Chad , Ruparel, Kosha , Susser, Ezra , Gur, Ruben C
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/302439 , vital:58196 , xlink:href="https://doi.org/10.1037/neu0000742"
- Description: Objective: Large-scale studies have revolutionized biomedical research, and neurocognitive tests can help elucidate the biological basis of neuropsychiatric diseases. However, studies have predominantly been conducted in Western settings. We describe the development and validation of a computerized battery (PennCNB) with the Xhosa population of South Africa. Method: Individuals with schizophrenia (n = 525) and a normative comparison group (n = 744) were balanced on age, sex, education, and region. Participants provided blood samples, were assessed psychiatrically, and were administered a PennCNB translation to isiXhosa, including measures of executive functions, episodic memory, complex cognition, social cognition, and sensorimotor speed. Feasibility was examined with test completion rates and input from administrators, and psychometric structural validity and associations with clinical and demographic characteristics were examined. Results: Tests were well tolerated by participants, as >87% had one (or fewer) test missing. Results suggested a similar factor structure to prior PennCNB studies in Western contexts, and expected age and sex effects were apparent. Furthermore, a similar profile of schizophrenia was observed, with neurocognitive deficits most pronounced for executive functions, especially attention, as well as memory, social cognition, and motor speed relative to complex cognition and sensorimotor speed. Conclusions: Results support the feasibility of implementing a culturally adapted computerized neurocognitive battery in sub-Saharan African settings and provide evidence supporting the concurrent validity of the translated instrument. Thus, the PennCNB is implementable on a large scale in non-Western contexts, shows expected factor structure, and can detect cognitive deficits associated with neuropsychiatric disorders. Obtaining valid measures of cognition by nonspecialized proctors is especially suitable in resource-limited settings, where traditional testing is prohibitive. Future work should establish normative standards, test–retest reliability, and sensitivity to treatment.
- Full Text:
- Date Issued: 2021
Adaptive machine learning based network intrusion detection
- Chindove, Hatitye, Brown, Dane L
- Authors: Chindove, Hatitye , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/464052 , vital:76471 , xlink:href="https://doi.org/10.1145/3487923.3487938"
- Description: Network intrusion detection system (NIDS) adoption is essential for mitigating computer network attacks in various scenarios. However, the increasing complexity of computer networks and attacks make it challenging to classify network traffic. Machine learning (ML) techniques in a NIDS can be affected by different scenarios, and thus the recency, size and applicability of datasets are vital factors to consider when selecting and tuning a machine learning classifier. The proposed approach evaluates relatively new datasets constructed such that they depict real-world scenarios. It includes analyses of dataset balancing and sampling, feature engineering and systematic ML-based NIDS model tuning focused on the adaptive improvement of intrusion detection. A comparison between machine learning classifiers forms part of the evaluation process. Results on the proposed approach model effectiveness for NIDS are discussed. Recurrent neural networks and random forests models consistently achieved high f1-score results with macro f1-scores of 0.73 and 0.87 for the CICIDS 2017 dataset; and 0.73 and 0.72 against the CICIDS 2018 dataset, respectively.
- Full Text:
- Date Issued: 2021
- Authors: Chindove, Hatitye , Brown, Dane L
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/464052 , vital:76471 , xlink:href="https://doi.org/10.1145/3487923.3487938"
- Description: Network intrusion detection system (NIDS) adoption is essential for mitigating computer network attacks in various scenarios. However, the increasing complexity of computer networks and attacks make it challenging to classify network traffic. Machine learning (ML) techniques in a NIDS can be affected by different scenarios, and thus the recency, size and applicability of datasets are vital factors to consider when selecting and tuning a machine learning classifier. The proposed approach evaluates relatively new datasets constructed such that they depict real-world scenarios. It includes analyses of dataset balancing and sampling, feature engineering and systematic ML-based NIDS model tuning focused on the adaptive improvement of intrusion detection. A comparison between machine learning classifiers forms part of the evaluation process. Results on the proposed approach model effectiveness for NIDS are discussed. Recurrent neural networks and random forests models consistently achieved high f1-score results with macro f1-scores of 0.73 and 0.87 for the CICIDS 2017 dataset; and 0.73 and 0.72 against the CICIDS 2018 dataset, respectively.
- Full Text:
- Date Issued: 2021
Addressing the red flags in cochineal identification: The use of molecular techniques to identify cochineal insects that are used as biological control agents for invasive alien cacti
- van Steenderen, Clarke J M, Paterson, Iain D, Edwards, Shelley, Day, Michael D
- Authors: van Steenderen, Clarke J M , Paterson, Iain D , Edwards, Shelley , Day, Michael D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423282 , vital:72044 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104426"
- Description: Invasive Cactaceae cause considerable damage to ecosystem function and agricultural practices around the world. The most successful biological control agents used to combat this group of weeds belong to the genus Dactylopius (Hemiptera: Dactylopiidae), commonly known as ‘cochineal’. Effective control relies on selecting the correct species, or in some cases, the most effective intraspecific lineage, of cochineal for the target cactus species. Many of the Dactylopius species are so morphologically similar, and in the case of intraspecific lineages, identical, that numerous misidentifications have been made in the past. These errors have resulted in failed attempts at the biological control of some cactus species. This study aimed to generate a multi-locus genetic database to enable the accurate identification of dactylopiids. Genetic characterization was achieved through the nucleotide sequencing of three gene regions (12S rRNA, 18S rRNA, and COI) and two inter-simple sequence repeats (ISSR). Nucleotide sequences were very effective for species-level and D. tomentosus lineage-level identification, but could not distinguish between the two lineages within D. opuntiae commonly used for biological control of various Opuntia spp. Fragment analysis through the use of ISSRs successfully addressed this issue. This is the first time that a method has been developed that can distinguish between these two D. opuntiae lineages. Using the methods developed in this study, biological control practitioners can ensure that the most effective agent species and lineages are used for each cactus target weed, thus maximizing the level of control.
- Full Text:
- Date Issued: 2021
- Authors: van Steenderen, Clarke J M , Paterson, Iain D , Edwards, Shelley , Day, Michael D
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423282 , vital:72044 , xlink:href="https://doi.org/10.1016/j.biocontrol.2020.104426"
- Description: Invasive Cactaceae cause considerable damage to ecosystem function and agricultural practices around the world. The most successful biological control agents used to combat this group of weeds belong to the genus Dactylopius (Hemiptera: Dactylopiidae), commonly known as ‘cochineal’. Effective control relies on selecting the correct species, or in some cases, the most effective intraspecific lineage, of cochineal for the target cactus species. Many of the Dactylopius species are so morphologically similar, and in the case of intraspecific lineages, identical, that numerous misidentifications have been made in the past. These errors have resulted in failed attempts at the biological control of some cactus species. This study aimed to generate a multi-locus genetic database to enable the accurate identification of dactylopiids. Genetic characterization was achieved through the nucleotide sequencing of three gene regions (12S rRNA, 18S rRNA, and COI) and two inter-simple sequence repeats (ISSR). Nucleotide sequences were very effective for species-level and D. tomentosus lineage-level identification, but could not distinguish between the two lineages within D. opuntiae commonly used for biological control of various Opuntia spp. Fragment analysis through the use of ISSRs successfully addressed this issue. This is the first time that a method has been developed that can distinguish between these two D. opuntiae lineages. Using the methods developed in this study, biological control practitioners can ensure that the most effective agent species and lineages are used for each cactus target weed, thus maximizing the level of control.
- Full Text:
- Date Issued: 2021