Anti-cancer and anti-trypanosomal properties of alkaloids from the root bark of Zanthoxylum leprieurii Guill and Perr
- Eze, Fabian I, Siwe-Noundou, Xavier, Isaacs, Michelle, Patala, Srivinas, Osadebe, Patience O, Krause, Rui W M
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Isaacs, Michelle , Patala, Srivinas , Osadebe, Patience O , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193352 , vital:45324 , xlink:href="http://dx.doi.org/10.4314/tjpr.v19i11.19"
- Description: Purpose: To isolate the anti-cancer and anti-trypanosomal principles of Zanthoxylum leprieurii, a medicinally versatile wild tropical plant used for managing tumours, African trypanosomiasis, and inflammation in southeastern Nigeria. Methods: The pure compounds were isolated using chromatographic methods. The structural elucidation of the pure compounds was based on their NMR (1D and 2D) and mass spectral data as well as chemical test results. Structure-activity relationships were based on the structural differences among the compounds. The cytotoxicity of the extracts and compounds (1, 2, 3, and 4) was evaluated in HeLa (human cervix adenocarcinoma) cell line while the trypanocidal activities were evaluated on Trypanosoma brucei brucei. Results: Two acridone alkaloids, 1-hydroxy-3-methoxy-10-methylacridin-9 (10H)-one, named fabiocinine (1), and 1-hydroxy-2,3-dimethoxy-10-methylacridin-9 (10H)-one (arborinine, 2), together with a furoquinoline alkaloid, skimmianine (3), and a chelerythrine derivative, 6-acetonyl-5,6-dihydrochelerythrine (4) were isolated from the root bark of Zanthoxylum leprieurii. Skimmianine (3) exhibited cytotoxicity and anti-trypanosomal IC50 of 12.8 and 13.2 µg/mL respectively (p less than 0.05). Compound (1) and arborinine (2) were selectively cytotoxic to HeLa cells with cytotoxicity IC50 of 28.49 and 62.71 µg/mL, respectively, while (4) did not show significant activity (p less than 0.05). Conclusion: Zanthoxylum leprieurii root bark contains cytotoxic and trypanocidal compounds, and is thus a potential source of anti-cancer and anti-trypanosomal leads.
- Full Text:
- Date Issued: 2020
- Authors: Eze, Fabian I , Siwe-Noundou, Xavier , Isaacs, Michelle , Patala, Srivinas , Osadebe, Patience O , Krause, Rui W M
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193352 , vital:45324 , xlink:href="http://dx.doi.org/10.4314/tjpr.v19i11.19"
- Description: Purpose: To isolate the anti-cancer and anti-trypanosomal principles of Zanthoxylum leprieurii, a medicinally versatile wild tropical plant used for managing tumours, African trypanosomiasis, and inflammation in southeastern Nigeria. Methods: The pure compounds were isolated using chromatographic methods. The structural elucidation of the pure compounds was based on their NMR (1D and 2D) and mass spectral data as well as chemical test results. Structure-activity relationships were based on the structural differences among the compounds. The cytotoxicity of the extracts and compounds (1, 2, 3, and 4) was evaluated in HeLa (human cervix adenocarcinoma) cell line while the trypanocidal activities were evaluated on Trypanosoma brucei brucei. Results: Two acridone alkaloids, 1-hydroxy-3-methoxy-10-methylacridin-9 (10H)-one, named fabiocinine (1), and 1-hydroxy-2,3-dimethoxy-10-methylacridin-9 (10H)-one (arborinine, 2), together with a furoquinoline alkaloid, skimmianine (3), and a chelerythrine derivative, 6-acetonyl-5,6-dihydrochelerythrine (4) were isolated from the root bark of Zanthoxylum leprieurii. Skimmianine (3) exhibited cytotoxicity and anti-trypanosomal IC50 of 12.8 and 13.2 µg/mL respectively (p less than 0.05). Compound (1) and arborinine (2) were selectively cytotoxic to HeLa cells with cytotoxicity IC50 of 28.49 and 62.71 µg/mL, respectively, while (4) did not show significant activity (p less than 0.05). Conclusion: Zanthoxylum leprieurii root bark contains cytotoxic and trypanocidal compounds, and is thus a potential source of anti-cancer and anti-trypanosomal leads.
- Full Text:
- Date Issued: 2020
Occurrence of selected endocrine disrupting compounds in the Eastern Cape province of South Africa:
- Farounbi, Adebayo I, Ngqwala, Nosiphiwe P
- Authors: Farounbi, Adebayo I , Ngqwala, Nosiphiwe P
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148447 , vital:38740 , DOI: 10.1007/s11356-020-08082-y
- Description: Endocrine-disrupting compounds are attracting attention worldwide because of their effects on living things in the environment. Ten endocrine disrupting compounds: 4-nonylphenol, 2,4-dichlorophenol, estrone, 17β-estradiol, bisphenol A, 4-tertoctylphenol, triclosan, atrazine, imidazole and 1,2,4-triazole were investigated in four rivers and wastewater treatment plants in this study. Rivers were sampled at upstream, midstream and downstream reaches, while the influent and effluent samples of wastewater were collected from treatment plants near the receiving rivers. Sample waters were freeze-dried followed by extraction of the organic content and purification by solid-phase extraction. Concentrations of the compounds in the samples were determined with ultra-high performance liquid chromatography-tandem mass spectrometry. The instrument was operated in the positive electrospray ionization (ESI) mode.
- Full Text:
- Date Issued: 2020
- Authors: Farounbi, Adebayo I , Ngqwala, Nosiphiwe P
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148447 , vital:38740 , DOI: 10.1007/s11356-020-08082-y
- Description: Endocrine-disrupting compounds are attracting attention worldwide because of their effects on living things in the environment. Ten endocrine disrupting compounds: 4-nonylphenol, 2,4-dichlorophenol, estrone, 17β-estradiol, bisphenol A, 4-tertoctylphenol, triclosan, atrazine, imidazole and 1,2,4-triazole were investigated in four rivers and wastewater treatment plants in this study. Rivers were sampled at upstream, midstream and downstream reaches, while the influent and effluent samples of wastewater were collected from treatment plants near the receiving rivers. Sample waters were freeze-dried followed by extraction of the organic content and purification by solid-phase extraction. Concentrations of the compounds in the samples were determined with ultra-high performance liquid chromatography-tandem mass spectrometry. The instrument was operated in the positive electrospray ionization (ESI) mode.
- Full Text:
- Date Issued: 2020
The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate creams
- Fauzee, Ayesha F B, Walker, Roderick B
- Authors: Fauzee, Ayesha F B , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183275 , vital:43937 , xlink:href="https://doi.org/10.1080/23311916.2020.1804713"
- Description: The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate (CP) cream formulations was investigated using a Central Composite Design of Experiments. Thirty batches of cream were manufactured and the formulation variables assessed were % v/v propylene glycol, % w/w Gelot® 64, cetostearyl alcohol and glyceryl monostearate content. The responses monitored included viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released at 72 hours. The responses were compared to those of a reference product, Dermovate® cream. ANOVA analysis revealed that viscosity, spreadability, and % CP released at 72 hours were significant formulation responses (p more than 0.05). Cetostearyl alcohol had the greatest impact on quality of pilot scale products. An increase in cetostearyl alcohol resulted in an increase in viscosity, a decrease in spreadability, and a decrease in % CP released at 72 hours. The optimized pilot scale CP formulation contained 46% v/v propylene glycol, 8.6% w/w cetostearyl alcohol, 10.5% w/w glyceryl monostearate, and 3.8% w/w Gelot® 64. The resultant viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released were 44633cP, 24.91cm2, 101.23 %, 76.98 g/cm2, 198.23 µS/cm, and 50.23%. The addition of cetostearyl alcohol and Gelot® 64 is critical for establishing a soft formulation that leads to the formation of a mixed crystal bilayer network of high viscosity. The formation of a separate crystalline lipophilic network usually occurs in semi-solid formulations that contain high concentrations of emulsifier, leading to an increase in shear stress and greater physicochemical stability of the formulation. The use of experimental design approaches to formulation development activities, permit evaluation of multiple factors simultaneously, reducing the time and costs associated with product development activities, whilst identifying a composition design space and ensuring stable and effective dosage forms are produced.
- Full Text:
- Date Issued: 2020
- Authors: Fauzee, Ayesha F B , Walker, Roderick B
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183275 , vital:43937 , xlink:href="https://doi.org/10.1080/23311916.2020.1804713"
- Description: The impact of formulation variables on the optimization of pilot scale clobetasol 17-propionate (CP) cream formulations was investigated using a Central Composite Design of Experiments. Thirty batches of cream were manufactured and the formulation variables assessed were % v/v propylene glycol, % w/w Gelot® 64, cetostearyl alcohol and glyceryl monostearate content. The responses monitored included viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released at 72 hours. The responses were compared to those of a reference product, Dermovate® cream. ANOVA analysis revealed that viscosity, spreadability, and % CP released at 72 hours were significant formulation responses (p more than 0.05). Cetostearyl alcohol had the greatest impact on quality of pilot scale products. An increase in cetostearyl alcohol resulted in an increase in viscosity, a decrease in spreadability, and a decrease in % CP released at 72 hours. The optimized pilot scale CP formulation contained 46% v/v propylene glycol, 8.6% w/w cetostearyl alcohol, 10.5% w/w glyceryl monostearate, and 3.8% w/w Gelot® 64. The resultant viscosity, spreadability, pH, CP content, extrudability, electrical conductivity, and % CP released were 44633cP, 24.91cm2, 101.23 %, 76.98 g/cm2, 198.23 µS/cm, and 50.23%. The addition of cetostearyl alcohol and Gelot® 64 is critical for establishing a soft formulation that leads to the formation of a mixed crystal bilayer network of high viscosity. The formation of a separate crystalline lipophilic network usually occurs in semi-solid formulations that contain high concentrations of emulsifier, leading to an increase in shear stress and greater physicochemical stability of the formulation. The use of experimental design approaches to formulation development activities, permit evaluation of multiple factors simultaneously, reducing the time and costs associated with product development activities, whilst identifying a composition design space and ensuring stable and effective dosage forms are produced.
- Full Text:
- Date Issued: 2020
Multi-layered risk management in under-resourced antenatal clinics
- Feltham-King, Tracey, Macleod, Catriona I
- Authors: Feltham-King, Tracey , Macleod, Catriona I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298561 , vital:57716 , xlink:href="https://doi.org/10.1080/13698575.2019.1697432"
- Description: In this article we contribute to critical risk approaches to studying pregnancy and childbirth in the global South. Following Sarah Rudrum’s work, our approach focusses on sociocultural inequalities amid the regulation of individuals. We draw on data from our Foucauldian-inspired ethnography of two antenatal clinics in an under-resourced area of South Africa to illustrate how multi-layered risk management operates in these spaces. These data were collected over a period of six months in the form of semi-structured interviews, observations of consultations and waiting room interactions, documents used in the clinic, and posters appearing on the clinic walls. Our findings show how a scientific-bureaucratic approach to pregnancy risk management, as encoded in international, national and institutional guidelines, is well known, highly visible, and practised through surveillance and reporting mechanisms in clinics. This approach incites healthcare practitioners to achieve particular performance standards and to monitor their professional agency. Managing pregnancy risk thus entails regulating the healthcare practitioners themselves. In implementing approved pregnancy risk management strategies in an over-subscribed and under-resourced public healthcare setting, however, healthcare practitioners face potential risk to their professional reputation and integrity. In managing this risk, they resist the scientific-bureaucratic approach through: depicting themselves as victims of unfair institutional arrangements or unreasonable patients; instituting street-level bureaucracy to control access to the clinics; and controlling patients’ actions in authoritarian ways. Our research shows that without engagement with the on-the-ground realities of the antenatal clinic in resource-poor environments, a scientific-bureaucratic approach to pregnancy risk management is inevitably limited in its effectiveness.
- Full Text:
- Date Issued: 2020
- Authors: Feltham-King, Tracey , Macleod, Catriona I
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298561 , vital:57716 , xlink:href="https://doi.org/10.1080/13698575.2019.1697432"
- Description: In this article we contribute to critical risk approaches to studying pregnancy and childbirth in the global South. Following Sarah Rudrum’s work, our approach focusses on sociocultural inequalities amid the regulation of individuals. We draw on data from our Foucauldian-inspired ethnography of two antenatal clinics in an under-resourced area of South Africa to illustrate how multi-layered risk management operates in these spaces. These data were collected over a period of six months in the form of semi-structured interviews, observations of consultations and waiting room interactions, documents used in the clinic, and posters appearing on the clinic walls. Our findings show how a scientific-bureaucratic approach to pregnancy risk management, as encoded in international, national and institutional guidelines, is well known, highly visible, and practised through surveillance and reporting mechanisms in clinics. This approach incites healthcare practitioners to achieve particular performance standards and to monitor their professional agency. Managing pregnancy risk thus entails regulating the healthcare practitioners themselves. In implementing approved pregnancy risk management strategies in an over-subscribed and under-resourced public healthcare setting, however, healthcare practitioners face potential risk to their professional reputation and integrity. In managing this risk, they resist the scientific-bureaucratic approach through: depicting themselves as victims of unfair institutional arrangements or unreasonable patients; instituting street-level bureaucracy to control access to the clinics; and controlling patients’ actions in authoritarian ways. Our research shows that without engagement with the on-the-ground realities of the antenatal clinic in resource-poor environments, a scientific-bureaucratic approach to pregnancy risk management is inevitably limited in its effectiveness.
- Full Text:
- Date Issued: 2020
PRECEPT: a framework for ethical digital forensics investigations
- Ferguson, R I, Renaud, Karen, Wilford, Sara, Irons, Alastair
- Authors: Ferguson, R I , Renaud, Karen , Wilford, Sara , Irons, Alastair
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149884 , vital:38909 , https://doi.org/10.1108/JIC-05-2019-00979
- Description: This paper argues the need for a practical, ethically grounded approach to digital forensic investigations, one that acknowledges and respects the privacy rights of individuals and the intellectual capital disclosure rights of organizations, as well as acknowledging the needs of law enforcement. The paper derives a set of ethical guidelines, and then maps these onto a forensics investigation framework. The framework to expert review in two stages is subjected, refining the framework after each stage. The paper concludes by proposing the refined ethically grounded digital forensics investigation framework. The treatise is primarily UK based, but the concepts presented here have international relevance and applicability.
- Full Text:
- Date Issued: 2020
- Authors: Ferguson, R I , Renaud, Karen , Wilford, Sara , Irons, Alastair
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149884 , vital:38909 , https://doi.org/10.1108/JIC-05-2019-00979
- Description: This paper argues the need for a practical, ethically grounded approach to digital forensic investigations, one that acknowledges and respects the privacy rights of individuals and the intellectual capital disclosure rights of organizations, as well as acknowledging the needs of law enforcement. The paper derives a set of ethical guidelines, and then maps these onto a forensics investigation framework. The framework to expert review in two stages is subjected, refining the framework after each stage. The paper concludes by proposing the refined ethically grounded digital forensics investigation framework. The treatise is primarily UK based, but the concepts presented here have international relevance and applicability.
- Full Text:
- Date Issued: 2020
Quantifying the impacts of abrasion and bacterial transfer when fish are exposed to sand during a catch-and-release event:
- Foster, Ryan M, Childs, Amber-Robyn, Brooks, Margot, Farthing, Matthew W, Butler, Edward C, Potts, Warren M
- Authors: Foster, Ryan M , Childs, Amber-Robyn , Brooks, Margot , Farthing, Matthew W , Butler, Edward C , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160427 , vital:40445 , https://doi.org/10.2989/1814232X.2020.1792982
- Description: Best-practice guidelines to improve recreational fishers’ handling during catch-and-release (CandR) events are critical to improve the conservation and management of fish stocks worldwide. While best-practice research is growing, there are knowledge gaps, with the effects of sand exposure on fish mucous membranes understudied. This study aimed to determine the effects of exposing a fish to sand during a CandR event. A total of 360 juvenile (48–137 mm TL) Cape stumpnose Rhabdosargus holubi were subjected to a simulated CandR event during which they were either held: (i) with wet hands, or (ii) dry hands; or with wet hands and then placed on either (iii) wet sterilised sand, (iv) dry sterilised sand, (v) wet unsterilised sand, or (vi) dry unsterilised sand. Fish were maintained in a recirculating system for two weeks, euthanised and subjected to an examination of their mucous layer (bacterial counts, abrasion counts and percentage of abrasion area) and an internal biological assessment. Bacteria fro m fish mucous layers were cultivated on agar plates to count bacterial colonies.
- Full Text:
- Date Issued: 2020
- Authors: Foster, Ryan M , Childs, Amber-Robyn , Brooks, Margot , Farthing, Matthew W , Butler, Edward C , Potts, Warren M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160427 , vital:40445 , https://doi.org/10.2989/1814232X.2020.1792982
- Description: Best-practice guidelines to improve recreational fishers’ handling during catch-and-release (CandR) events are critical to improve the conservation and management of fish stocks worldwide. While best-practice research is growing, there are knowledge gaps, with the effects of sand exposure on fish mucous membranes understudied. This study aimed to determine the effects of exposing a fish to sand during a CandR event. A total of 360 juvenile (48–137 mm TL) Cape stumpnose Rhabdosargus holubi were subjected to a simulated CandR event during which they were either held: (i) with wet hands, or (ii) dry hands; or with wet hands and then placed on either (iii) wet sterilised sand, (iv) dry sterilised sand, (v) wet unsterilised sand, or (vi) dry unsterilised sand. Fish were maintained in a recirculating system for two weeks, euthanised and subjected to an examination of their mucous layer (bacterial counts, abrasion counts and percentage of abrasion area) and an internal biological assessment. Bacteria fro m fish mucous layers were cultivated on agar plates to count bacterial colonies.
- Full Text:
- Date Issued: 2020
Synthesis and pharmacological evaluation of chlorin derivatives for photodynamic therapy of cholangiocarcinoma
- Gao, Ying-Hua, Li, Man-Yi, Saijad, Faiza, Wang, Jin-Hai, Meharban, Faiza, Gadoora, Malaz A, Yan, Yi-Jia, Nyokong, Tebello, Chen, Zhi-Long
- Authors: Gao, Ying-Hua , Li, Man-Yi , Saijad, Faiza , Wang, Jin-Hai , Meharban, Faiza , Gadoora, Malaz A , Yan, Yi-Jia , Nyokong, Tebello , Chen, Zhi-Long
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190873 , vital:45036 , xlink:href="https://doi.org/10.1016/j.ejmech.2020.112049"
- Description: Photodynamic therapy (PDT) has been developed as a promising therapeutic method in cancer treatment. The discovery of effective photosensitizer, which is the key factor of PDT, is highly desired. This paper reports the synthesis of novel chlorin derivatives, 5,10,15,20-tetraphenyl-[2:3]-[(methoxycarbonyl, carboxy)methano] chlorin I and 5,10,15,20-tetraphenyl-[2:3]- {[methoxycarbonyl, (2-hydroxyethyl)amide]methano}chlorin II. Their structures were characterized with UV–vis, 1HNMR, 13CNMR and HRMS spectroscopies. Photophysical and photochemical experiments results showed that compound I and II had an absorption maximum around 650 nm, with molar extinction coefficients of 1 × 104 M−1 cm−1. They had strong fluorescence emission in 650–660 nm upon excitation with 419–422 nm light. ESR showed that singlet oxygen was produced upon irradiation of compounds with 650 nm light in the presence of molecular oxygen. The photo-bleaching test indicated that the structure of compounds was stable. These new compounds exhibit excellent anti-tumor effects and lower toxicity compared to m-THPC in vitro and in vivo. Compound I and II had high tumor selectivity, which could induced tumor cells shrinkage and necrosis under 650 nm laser irradiation. Flow cytometry revealed that the compounds might mediate PDT effect at late apoptotic phase. These results make these compound I and II promising candidates for future study in photo-diagnosis and photodynamic therapy of cholangiocarcinoma.
- Full Text:
- Date Issued: 2020
- Authors: Gao, Ying-Hua , Li, Man-Yi , Saijad, Faiza , Wang, Jin-Hai , Meharban, Faiza , Gadoora, Malaz A , Yan, Yi-Jia , Nyokong, Tebello , Chen, Zhi-Long
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190873 , vital:45036 , xlink:href="https://doi.org/10.1016/j.ejmech.2020.112049"
- Description: Photodynamic therapy (PDT) has been developed as a promising therapeutic method in cancer treatment. The discovery of effective photosensitizer, which is the key factor of PDT, is highly desired. This paper reports the synthesis of novel chlorin derivatives, 5,10,15,20-tetraphenyl-[2:3]-[(methoxycarbonyl, carboxy)methano] chlorin I and 5,10,15,20-tetraphenyl-[2:3]- {[methoxycarbonyl, (2-hydroxyethyl)amide]methano}chlorin II. Their structures were characterized with UV–vis, 1HNMR, 13CNMR and HRMS spectroscopies. Photophysical and photochemical experiments results showed that compound I and II had an absorption maximum around 650 nm, with molar extinction coefficients of 1 × 104 M−1 cm−1. They had strong fluorescence emission in 650–660 nm upon excitation with 419–422 nm light. ESR showed that singlet oxygen was produced upon irradiation of compounds with 650 nm light in the presence of molecular oxygen. The photo-bleaching test indicated that the structure of compounds was stable. These new compounds exhibit excellent anti-tumor effects and lower toxicity compared to m-THPC in vitro and in vivo. Compound I and II had high tumor selectivity, which could induced tumor cells shrinkage and necrosis under 650 nm laser irradiation. Flow cytometry revealed that the compounds might mediate PDT effect at late apoptotic phase. These results make these compound I and II promising candidates for future study in photo-diagnosis and photodynamic therapy of cholangiocarcinoma.
- Full Text:
- Date Issued: 2020
Urban foraging of wild plants in two medium-sized South African towns: People, perceptions and practices
- Garekae, Hesekia, Shackleton, Charlie M
- Authors: Garekae, Hesekia , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176333 , vital:42685 , https://doi.org/10.1016/j.ufug.2020.126581
- Description: Urban ecosystems provide goods and services critical to livelihood sustenance, environmental protection and sustainability. However, the potential role of some urban ecosystem services such as the provisioning services, to promote liveable cities and livelihood resilience is seldom considered. This study reports on the prevalence and pattern of wild plant foraging and uses in the towns of Potchefstroom and Thabazimbi, South Africa, based on a random sample of 374 households. Descriptive and inferential statistics were used for analysing data. Foraging wild plants was integral to livelihoods and traditions and provided household energy, dietary diversity, health, and cultural affirmation, among others. About 68 % of the respondents reported foraging wild plants, albeit at varying degrees between and within towns.
- Full Text:
- Date Issued: 2020
- Authors: Garekae, Hesekia , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176333 , vital:42685 , https://doi.org/10.1016/j.ufug.2020.126581
- Description: Urban ecosystems provide goods and services critical to livelihood sustenance, environmental protection and sustainability. However, the potential role of some urban ecosystem services such as the provisioning services, to promote liveable cities and livelihood resilience is seldom considered. This study reports on the prevalence and pattern of wild plant foraging and uses in the towns of Potchefstroom and Thabazimbi, South Africa, based on a random sample of 374 households. Descriptive and inferential statistics were used for analysing data. Foraging wild plants was integral to livelihoods and traditions and provided household energy, dietary diversity, health, and cultural affirmation, among others. About 68 % of the respondents reported foraging wild plants, albeit at varying degrees between and within towns.
- Full Text:
- Date Issued: 2020
Foraging wild food in urban spaces: The contribution of wild foods to urban dietary diversity in South Africa
- Garekae, Hesekia, Shackleton, Charlie M
- Authors: Garekae, Hesekia , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176368 , vital:42688 , https://doi.org/10.3390/su12020678
- Description: Globally, approximately one billion people benefit from contributions of wild foods to their food security and dietary diversity. Wild foods are known to be important in rural communities in terms of food and micronutrient provision, diversifying diets, reducing vulnerability to non-communicable diseases and overall health. However, the potential contribution of wild foods towards food security and dietary diversity in urban food systems has been largely overlooked. This study examined the contribution of wild foods to household dietary diversity in two towns in South Africa, based on a survey of 137 households.
- Full Text:
- Date Issued: 2020
- Authors: Garekae, Hesekia , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176368 , vital:42688 , https://doi.org/10.3390/su12020678
- Description: Globally, approximately one billion people benefit from contributions of wild foods to their food security and dietary diversity. Wild foods are known to be important in rural communities in terms of food and micronutrient provision, diversifying diets, reducing vulnerability to non-communicable diseases and overall health. However, the potential contribution of wild foods towards food security and dietary diversity in urban food systems has been largely overlooked. This study examined the contribution of wild foods to household dietary diversity in two towns in South Africa, based on a survey of 137 households.
- Full Text:
- Date Issued: 2020
BTC price volatility: fundamentals versus information
- Gbadebo, Adedeji Daniel, Adekunle, Ahmed Oluwatobi, Adebayo-Oke Abdulrauf Lukman, Adedokun, Wole, Akande, Joseph
- Authors: Gbadebo, Adedeji Daniel , Adekunle, Ahmed Oluwatobi , Adebayo-Oke Abdulrauf Lukman , Adedokun, Wole , Akande, Joseph
- Date: 2020
- Subjects: Bitcoin price volatility , Bitcoin market fundamentals , Autoregressive Distributed Lag (ARDL)
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/11260/6978 , vital:52630 , https://doi.org/10.1080/23311975.2021.1984624
- Description: This paper offers a plausible response to “what explains the sporadic volatility in the price of Bitcoin?” We hypothesized that market “fundamentals” and “information demands” are key drivers of Bitcoin’s unpredictable price fluctuation. We adopt the transfer-function [Autoregressive Distributed Lag, ARDL] model and its Bounds testing approach to verify how the volatility of the price of Bitcoin responds to its transaction volume, cryptocurrency market capitalisation, world market equity index and Google search. We found the existence of long-run cointegration relation and observed that all the variables except the equity index positively explain the volatility of Bitcoin price. The result established evidence that market fundamentals drive erratic swing in Bitcoin price than information.
- Full Text:
- Date Issued: 2020
- Authors: Gbadebo, Adedeji Daniel , Adekunle, Ahmed Oluwatobi , Adebayo-Oke Abdulrauf Lukman , Adedokun, Wole , Akande, Joseph
- Date: 2020
- Subjects: Bitcoin price volatility , Bitcoin market fundamentals , Autoregressive Distributed Lag (ARDL)
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/11260/6978 , vital:52630 , https://doi.org/10.1080/23311975.2021.1984624
- Description: This paper offers a plausible response to “what explains the sporadic volatility in the price of Bitcoin?” We hypothesized that market “fundamentals” and “information demands” are key drivers of Bitcoin’s unpredictable price fluctuation. We adopt the transfer-function [Autoregressive Distributed Lag, ARDL] model and its Bounds testing approach to verify how the volatility of the price of Bitcoin responds to its transaction volume, cryptocurrency market capitalisation, world market equity index and Google search. We found the existence of long-run cointegration relation and observed that all the variables except the equity index positively explain the volatility of Bitcoin price. The result established evidence that market fundamentals drive erratic swing in Bitcoin price than information.
- Full Text:
- Date Issued: 2020
High genetic diversity and limited spatial structure in an endangered, endemic South African sparid, the red steenbras Petrus rupestris:
- Gouws, G, Kerwath, S E, Potts, Warren M, James, Nicola C, Vine, Niall G, Cowley, Paul D
- Authors: Gouws, G , Kerwath, S E , Potts, Warren M , James, Nicola C , Vine, Niall G , Cowley, Paul D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160379 , vital:40440 , DOI: 10.2989/1814232X.2020.1788640
- Description: The red steenbras Petrus rupestris is endemic to South Africa, occurring from False Bay in the Western Cape Province to St Lucia in the province of KwaZulu-Natal. This species, the largest member of the family Sparidae, has undergone a substantial stock decline as a result of overfishing and is considered to be collapsed. Various aspects of its life history, including high residency, predictable migrations, late maturity and longevity, have made it vulnerable to overexploitation. This study analysed the diversity and genetic structure of red steenbras across seven sampling regions, using mitochondrial (control region) and nuclear (S7 intron 1) DNA markers.
- Full Text:
- Date Issued: 2020
- Authors: Gouws, G , Kerwath, S E , Potts, Warren M , James, Nicola C , Vine, Niall G , Cowley, Paul D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160379 , vital:40440 , DOI: 10.2989/1814232X.2020.1788640
- Description: The red steenbras Petrus rupestris is endemic to South Africa, occurring from False Bay in the Western Cape Province to St Lucia in the province of KwaZulu-Natal. This species, the largest member of the family Sparidae, has undergone a substantial stock decline as a result of overfishing and is considered to be collapsed. Various aspects of its life history, including high residency, predictable migrations, late maturity and longevity, have made it vulnerable to overexploitation. This study analysed the diversity and genetic structure of red steenbras across seven sampling regions, using mitochondrial (control region) and nuclear (S7 intron 1) DNA markers.
- Full Text:
- Date Issued: 2020
Expansive learning in the leadership development of school learners
- Grant, Carolyn, Kajee, Farhana Amod
- Authors: Grant, Carolyn , Kajee, Farhana Amod
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281072 , vital:55689 , xlink:href="https://doi.org/10.1080/13603124.2020.1836405"
- Description: In many countries across the globe, and on the African continent in particular, young people do not have a voice in matters concerning their schooling. By virtue of their minor status, opportunities for participatory decision-making and leadership in schools are restricted, despite national policies to the contrary. This is all-too-often because leadership is (mis)understood as an adult phenomenon. In this article, we present a formative intervention, ‘Learners Lead’, which aimed at developing learner voice and leadership in learners through collective involvement in school change projects. Formulated as a documentary case study, data were generated from 95 research reports, the written assessments of the students registered for the Educational Leadership and Management elective within a postgraduate qualification in a South African university. Analysis drew on the pyramid of learner voice and the theory of expansive learning to examine if, and how, leadership development in learners occurred. The study found that expansive learning’s seven learning actions provided the necessary additional theoretical tools for understanding and unpacking the stages of leadership development as the school change projects unfolded. Implications for practice and research are discussed.
- Full Text:
- Date Issued: 2020
- Authors: Grant, Carolyn , Kajee, Farhana Amod
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281072 , vital:55689 , xlink:href="https://doi.org/10.1080/13603124.2020.1836405"
- Description: In many countries across the globe, and on the African continent in particular, young people do not have a voice in matters concerning their schooling. By virtue of their minor status, opportunities for participatory decision-making and leadership in schools are restricted, despite national policies to the contrary. This is all-too-often because leadership is (mis)understood as an adult phenomenon. In this article, we present a formative intervention, ‘Learners Lead’, which aimed at developing learner voice and leadership in learners through collective involvement in school change projects. Formulated as a documentary case study, data were generated from 95 research reports, the written assessments of the students registered for the Educational Leadership and Management elective within a postgraduate qualification in a South African university. Analysis drew on the pyramid of learner voice and the theory of expansive learning to examine if, and how, leadership development in learners occurred. The study found that expansive learning’s seven learning actions provided the necessary additional theoretical tools for understanding and unpacking the stages of leadership development as the school change projects unfolded. Implications for practice and research are discussed.
- Full Text:
- Date Issued: 2020
Genetics of schizophrenia in the South African Xhosa
- Gulsuner, S, Stein, D J, Susser, E S, Sibeko, G, Pretorius, A, Walsh, T, Majara, L, Mndini, M M, Mqulwana, S G, Ntola, O A, Casadei, S, Zingela, Zukiswa, Nagdee, M, Ramesar, R S, King, M-C, McClellan, J M, Ngqengelele, L L, Korchina, V, van der Merwe, C, Malan, M, Fader, K M, Feng, M, Willoughby, E, Munzi, D, Andrews, H F, Gur, R C, Gibbs, R A
- Authors: Gulsuner, S , Stein, D J , Susser, E S , Sibeko, G , Pretorius, A , Walsh, T , Majara, L , Mndini, M M , Mqulwana, S G , Ntola, O A , Casadei, S , Zingela, Zukiswa , Nagdee, M , Ramesar, R S , King, M-C , McClellan, J M , Ngqengelele, L L , Korchina, V , van der Merwe, C , Malan, M , Fader, K M , Feng, M , Willoughby, E , Munzi, D , Andrews, H F , Gur, R C , Gibbs, R A
- Date: 2020
- Subjects: Schizophrenia -- Diagnosis -- Cross-cultural studies , Medical genetics , Xhosa (African people)
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4217 , vital:44044 , https://doi.org/10.1126/science.aay8833
- Description: Africa, the ancestral home of all modern humans, is the most informative continent for understanding the human genome and its contribution to complex disease. To better understand the genetics of schizophrenia, we studied the illness in the Xhosa population of South Africa, recruiting 909 cases and 917 age-, gender-, and residence-matched controls. Individuals with schizophrenia were significantly more likely than controls to harbor private, severely damaging mutations in genes that are critical to synaptic function, including neural circuitry mediated by the neurotransmitters glutamine, γ-aminobutyric acid, and dopamine. Schizophrenia is genetically highly heterogeneous, involving severe ultrarare mutations in genes that are critical to synaptic plasticity. The depth of genetic variation in Africa revealed this relationship with a moderate sample size and informed our understanding of the genetics of schizophrenia worldwide.
- Full Text:
- Date Issued: 2020
- Authors: Gulsuner, S , Stein, D J , Susser, E S , Sibeko, G , Pretorius, A , Walsh, T , Majara, L , Mndini, M M , Mqulwana, S G , Ntola, O A , Casadei, S , Zingela, Zukiswa , Nagdee, M , Ramesar, R S , King, M-C , McClellan, J M , Ngqengelele, L L , Korchina, V , van der Merwe, C , Malan, M , Fader, K M , Feng, M , Willoughby, E , Munzi, D , Andrews, H F , Gur, R C , Gibbs, R A
- Date: 2020
- Subjects: Schizophrenia -- Diagnosis -- Cross-cultural studies , Medical genetics , Xhosa (African people)
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/4217 , vital:44044 , https://doi.org/10.1126/science.aay8833
- Description: Africa, the ancestral home of all modern humans, is the most informative continent for understanding the human genome and its contribution to complex disease. To better understand the genetics of schizophrenia, we studied the illness in the Xhosa population of South Africa, recruiting 909 cases and 917 age-, gender-, and residence-matched controls. Individuals with schizophrenia were significantly more likely than controls to harbor private, severely damaging mutations in genes that are critical to synaptic function, including neural circuitry mediated by the neurotransmitters glutamine, γ-aminobutyric acid, and dopamine. Schizophrenia is genetically highly heterogeneous, involving severe ultrarare mutations in genes that are critical to synaptic plasticity. The depth of genetic variation in Africa revealed this relationship with a moderate sample size and informed our understanding of the genetics of schizophrenia worldwide.
- Full Text:
- Date Issued: 2020
Reimagining academic identities in response to research demands at Universities of Technology
- Gumbi, Thobani, McKenna, Sioux
- Authors: Gumbi, Thobani , McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185897 , vital:44446 , xlink:href="https://doi.org/10.14426/cristal.v8i1.234"
- Description: In the last volume of this journal, Garraway and Winberg called for a reimagination of Universities of Technology (UoT) within the South African higher education system. This article continues that conversation by looking at the implications that the formation of the UoT had for academics’ identities. Technikon lecturers’ identities were closely tied to workplace expertise, but demands for research in UoTs have changed this. A social realist analysis of interviews with fifteen academics at three UoTs finds that research remains a contested issue. Interviewees understood research to take the form of acquiring postgraduate qualifications, rather than as an ongoing activity tied to their identities. Echoing Garraway and Winberg’s study, the bureaucratic nature of the institutional culture was referred to as a constraint. There was also a view that for this programme, Dental Technology, a demand for research was needed from industry if this was to be a valued aspect of academics’ identities.
- Full Text:
- Date Issued: 2020
- Authors: Gumbi, Thobani , McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185897 , vital:44446 , xlink:href="https://doi.org/10.14426/cristal.v8i1.234"
- Description: In the last volume of this journal, Garraway and Winberg called for a reimagination of Universities of Technology (UoT) within the South African higher education system. This article continues that conversation by looking at the implications that the formation of the UoT had for academics’ identities. Technikon lecturers’ identities were closely tied to workplace expertise, but demands for research in UoTs have changed this. A social realist analysis of interviews with fifteen academics at three UoTs finds that research remains a contested issue. Interviewees understood research to take the form of acquiring postgraduate qualifications, rather than as an ongoing activity tied to their identities. Echoing Garraway and Winberg’s study, the bureaucratic nature of the institutional culture was referred to as a constraint. There was also a view that for this programme, Dental Technology, a demand for research was needed from industry if this was to be a valued aspect of academics’ identities.
- Full Text:
- Date Issued: 2020
An effort to study the influence of tides on the longitudinal variation of vertical E× B drift over the African sector:
- Habyarimana, Valence, Habarulema, John B, Mungufeni, Patrick, Uwamahoro, Jean C
- Authors: Habyarimana, Valence , Habarulema, John B , Mungufeni, Patrick , Uwamahoro, Jean C
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149026 , vital:38797 , https://doi.org/10.1016/j.jastp.2020.105338
- Description: Meteorological processes such as tides influence ionospheric variability through vertical coupling. For the first time, we have used data from Communication Navigation Outage and Forecasting System (C/NOFS) satellite from 2008–2015 to develop a Neural Network (NN) vertical E×B drift model over the African region, with inclusion of a proxy of tides as one of the inputs together with other physical and geophysical inputs. Two models (with and without tidal proxy input) were developed for both East and West African sectors. To derive the tidal proxy, we first calculate the 60-day running means per year which were subtracted from the actual vertical E×B drift measurements to obtain a set of residuals. The purpose of the subtraction was to remove long-term trends in vertical E×B drift that could potentially alias into tides.
- Full Text:
- Date Issued: 2020
- Authors: Habyarimana, Valence , Habarulema, John B , Mungufeni, Patrick , Uwamahoro, Jean C
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149026 , vital:38797 , https://doi.org/10.1016/j.jastp.2020.105338
- Description: Meteorological processes such as tides influence ionospheric variability through vertical coupling. For the first time, we have used data from Communication Navigation Outage and Forecasting System (C/NOFS) satellite from 2008–2015 to develop a Neural Network (NN) vertical E×B drift model over the African region, with inclusion of a proxy of tides as one of the inputs together with other physical and geophysical inputs. Two models (with and without tidal proxy input) were developed for both East and West African sectors. To derive the tidal proxy, we first calculate the 60-day running means per year which were subtracted from the actual vertical E×B drift measurements to obtain a set of residuals. The purpose of the subtraction was to remove long-term trends in vertical E×B drift that could potentially alias into tides.
- Full Text:
- Date Issued: 2020
Using action cameras to estimate the abundance and habitat use of threatened fish in clear headwater streams:
- Hannweg, B, Marr, S M, Bloy, Lesley E, Weyl, Olaf L F
- Authors: Hannweg, B , Marr, S M , Bloy, Lesley E , Weyl, Olaf L F
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148911 , vital:38785 , DOI: 10.2989/16085914.2019.1701404
- Description: Snorkel and electrofishing surveys are the traditional baseline methods for fish surveys in clear headwater streams. However, action cameras provide a non-harmful alternative to monitor freshwater fish populations to develop informed conservation management initiatives. In this paper, estimates from photographs and videos from action cameras are compared with snorkel survey estimates of the density of a threatened endemic minnow species in a headwater stream, Eastern Cape, South Africa. Photograph-based relative abundances of fish summed over five microhabitats in each pool returned equivalent results to snorkel surveys, whereas the equivalent video-based abundance estimates were approximately 50% greater than the snorkel estimates. Therefore, photograph-derived estimates could be used as an alternative to snorkel surveys for fish population monitoring and habitat use studies in clear headwater streams.
- Full Text:
- Date Issued: 2020
- Authors: Hannweg, B , Marr, S M , Bloy, Lesley E , Weyl, Olaf L F
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148911 , vital:38785 , DOI: 10.2989/16085914.2019.1701404
- Description: Snorkel and electrofishing surveys are the traditional baseline methods for fish surveys in clear headwater streams. However, action cameras provide a non-harmful alternative to monitor freshwater fish populations to develop informed conservation management initiatives. In this paper, estimates from photographs and videos from action cameras are compared with snorkel survey estimates of the density of a threatened endemic minnow species in a headwater stream, Eastern Cape, South Africa. Photograph-based relative abundances of fish summed over five microhabitats in each pool returned equivalent results to snorkel surveys, whereas the equivalent video-based abundance estimates were approximately 50% greater than the snorkel estimates. Therefore, photograph-derived estimates could be used as an alternative to snorkel surveys for fish population monitoring and habitat use studies in clear headwater streams.
- Full Text:
- Date Issued: 2020
A snapshot of early childhood care and education in South Africa: institutional offerings, challenges and recommendations
- Authors: Harrison, Giulietta D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160312 , vital:40433 , https://doi.org/10.4102/sajce.v10i1.797
- Description: This article draws from a research report on the Project for Inclusive Early Childhood Care and Education (PIECCE), which surveyed attitudes, training strategies, materials and entrance requirements across most relevant higher education institutions (HEIs), non-governmental organisations (NGOs) and technical and vocational education and training colleges (TVETs). The aim of this study was to identify what institutions were offering in terms of training teachers in the birth-to-four age group, to identify the challenges and provide recommendations based on the findings.
- Full Text:
- Date Issued: 2020
- Authors: Harrison, Giulietta D
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160312 , vital:40433 , https://doi.org/10.4102/sajce.v10i1.797
- Description: This article draws from a research report on the Project for Inclusive Early Childhood Care and Education (PIECCE), which surveyed attitudes, training strategies, materials and entrance requirements across most relevant higher education institutions (HEIs), non-governmental organisations (NGOs) and technical and vocational education and training colleges (TVETs). The aim of this study was to identify what institutions were offering in terms of training teachers in the birth-to-four age group, to identify the challenges and provide recommendations based on the findings.
- Full Text:
- Date Issued: 2020
An improved systems approach as a phytosanitary measure for Thaumatotibia leucotreta (Lepidoptera: Tortricidae) in export citrus fruit from South Africa
- Hattingh, Vaughan, Moore, Sean D, Kirkman, Wayne, Goddard, Mat, Thackeray, Sean, Peyper, Mellissa, Sharp, Gary, Cronjé, Paul, Pringle, Ken
- Authors: Hattingh, Vaughan , Moore, Sean D , Kirkman, Wayne , Goddard, Mat , Thackeray, Sean , Peyper, Mellissa , Sharp, Gary , Cronjé, Paul , Pringle, Ken
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423700 , vital:72086 , xlink:href="https://doi.org/10.1093/jee/toz336"
- Description: A systems approach was previously developed for mitigating phytosanitary risk of Thaumatotibia leucotreta (Meyrick) in citrus fruit exported from South Africa, as an alternative to a standalone cold disinfestation treatment. The present study first tested the original systems approach by applying it on a semicommercial scale in 10 Nova mandarin orchards. Fruit were inspected at points in the production, packing, and simulated shipping process, to assess performance of the systems approach. Additional data were obtained from 17 Valencia orange orchards and six packinghouses. In the second part of this study, the systems approach was accordingly revised and improved, consisting of three measures: 1) preharvest controls and measurements and postpicking sampling, inspection, and packinghouse procedures; 2) postpacking sampling and inspection; and 3) shipping conditions. The model quantifying the effectiveness of the systems approach was improved by correcting errors in the original version, updating parameter values and adding a component that provides for comparison with the risk mitigation provided by a standalone disinfestation treatment. Consequently, the maximum potential proportion of fruit that may be infested with live T. leucotreta after application of the improved systems approach is no greater than the proportion of fruit that may be infested after application of a Probit 9 efficacy postharvest disinfestation treatment to fruit with a 2% pretreatment infestation. The probability of a mating pair surviving is also determined. The model enables a priori determination of the required threshold levels for any of the three measures, based on quantification of the other two measures.
- Full Text:
- Date Issued: 2020
- Authors: Hattingh, Vaughan , Moore, Sean D , Kirkman, Wayne , Goddard, Mat , Thackeray, Sean , Peyper, Mellissa , Sharp, Gary , Cronjé, Paul , Pringle, Ken
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423700 , vital:72086 , xlink:href="https://doi.org/10.1093/jee/toz336"
- Description: A systems approach was previously developed for mitigating phytosanitary risk of Thaumatotibia leucotreta (Meyrick) in citrus fruit exported from South Africa, as an alternative to a standalone cold disinfestation treatment. The present study first tested the original systems approach by applying it on a semicommercial scale in 10 Nova mandarin orchards. Fruit were inspected at points in the production, packing, and simulated shipping process, to assess performance of the systems approach. Additional data were obtained from 17 Valencia orange orchards and six packinghouses. In the second part of this study, the systems approach was accordingly revised and improved, consisting of three measures: 1) preharvest controls and measurements and postpicking sampling, inspection, and packinghouse procedures; 2) postpacking sampling and inspection; and 3) shipping conditions. The model quantifying the effectiveness of the systems approach was improved by correcting errors in the original version, updating parameter values and adding a component that provides for comparison with the risk mitigation provided by a standalone disinfestation treatment. Consequently, the maximum potential proportion of fruit that may be infested with live T. leucotreta after application of the improved systems approach is no greater than the proportion of fruit that may be infested after application of a Probit 9 efficacy postharvest disinfestation treatment to fruit with a 2% pretreatment infestation. The probability of a mating pair surviving is also determined. The model enables a priori determination of the required threshold levels for any of the three measures, based on quantification of the other two measures.
- Full Text:
- Date Issued: 2020
Ecosystem disservices matter when valuing ecosystem benefits from small-scale arable agriculture:
- Herd-Hoare, Shannon C, Shackleton, Charlie M
- Authors: Herd-Hoare, Shannon C , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175744 , vital:42620 , https://doi.org/10.1016/j.ecoser.2020.101201
- Description: The contribution of ecosystem services to smallholder agriculture is widely recognised. However, they are seldom analysed in tandem with the ecosystem disservices, such as crop weeds and pests, which the same systems produce. We do so by quantifying the provisioning ecosystem services and disservices in smallholder arable agricultural systems in three rural villages in southeastern South Africa. Using a mixed methods approach we consider the relative benefits from ecosystem services after the effects of disservices, and the management and strategies that households adopt to minimise disservices. The role of ecosystem services and disservices was expressed in economic terms to provide a common framework to assess the relative magnitude of their contribution or loss.
- Full Text:
- Date Issued: 2020
- Authors: Herd-Hoare, Shannon C , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/175744 , vital:42620 , https://doi.org/10.1016/j.ecoser.2020.101201
- Description: The contribution of ecosystem services to smallholder agriculture is widely recognised. However, they are seldom analysed in tandem with the ecosystem disservices, such as crop weeds and pests, which the same systems produce. We do so by quantifying the provisioning ecosystem services and disservices in smallholder arable agricultural systems in three rural villages in southeastern South Africa. Using a mixed methods approach we consider the relative benefits from ecosystem services after the effects of disservices, and the management and strategies that households adopt to minimise disservices. The role of ecosystem services and disservices was expressed in economic terms to provide a common framework to assess the relative magnitude of their contribution or loss.
- Full Text:
- Date Issued: 2020
Integrating Ecosystem Services and Disservices in Valuing Smallholder Livestock and Poultry Production in Three Villages in South Africa
- Herd-Hoare, Shannon C, Shackleton, Charlie M
- Authors: Herd-Hoare, Shannon C , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176089 , vital:42659 , https://doi.org/10.1016/j.ufug.2020.126740 , https://doi.org/10.21504/RUR.c.5388515.v1
- Description: This study presents an integrated examination of both the ecosystem services (ES) and ecosystem disservices (EDS) associated with smallholder animal husbandry in rural livelihoods in three villages in southeast South Africa. It recognises the contribution of ES supporting and resulting from smallholder livestock and poultry production, but also details the limiting factors or EDS, such as tick-borne disease, birds of prey or unpalatable rangeland, produced by the same system. Using a mixed-methods approach, including focus group discussions with various Participatory Learning and Action (PLA) activities, key informant interviews, household surveys and land-use change mapping on GIS, we consider the relative value and benefits from ES after the effects of EDS, as well as the management and strategies that households adopt to minimise EDS.
- Full Text:
- Date Issued: 2020
- Authors: Herd-Hoare, Shannon C , Shackleton, Charlie M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/176089 , vital:42659 , https://doi.org/10.1016/j.ufug.2020.126740 , https://doi.org/10.21504/RUR.c.5388515.v1
- Description: This study presents an integrated examination of both the ecosystem services (ES) and ecosystem disservices (EDS) associated with smallholder animal husbandry in rural livelihoods in three villages in southeast South Africa. It recognises the contribution of ES supporting and resulting from smallholder livestock and poultry production, but also details the limiting factors or EDS, such as tick-borne disease, birds of prey or unpalatable rangeland, produced by the same system. Using a mixed-methods approach, including focus group discussions with various Participatory Learning and Action (PLA) activities, key informant interviews, household surveys and land-use change mapping on GIS, we consider the relative value and benefits from ES after the effects of EDS, as well as the management and strategies that households adopt to minimise EDS.
- Full Text:
- Date Issued: 2020