Household dietary patterns and food security challenges in Peri-Urban South Africa: A reflection of high unemployment in the wake of rising food prices
- Authors: Chakona, Gamuchirai
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433943 , vital:73013 , ISBN 978-3-030-93072-1 , https://doi.org/10.1007/978-3-030-93072-1_11
- Description: Urbanization is one of the major social changes sweeping the globe, with rapid growth of the urban population and stagnating growth of the rural population, especially in developing regions (UN-Habitat, 2020). In subSaharan Africa, rapid urbanization and poverty are the major fundamental development challenges that are perpetuating and deepening the crisis of food and nutrition insecurity in urban areas (Battersby, 2012). Many people living in urban areas face under-nutrition, mainly due to their lack of income rather than to a lack of capacity to produce food (Satterthwaite et al., 2010). The health and nutritional status of urban populations with very low incomes are at risk from rising prices in staple foods. This became evident with the rising hunger among urban populations after the food price rises in 2007 and the first half of 2008 (Cohen and Garrett, 2009). In South Africa, poverty, unemployment and high food prices are dominant and influence dietary change, which subsequently increases urban food insecurity and malnutrition (Battersby, 2012).
- Full Text:
- Authors: Chakona, Gamuchirai
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433943 , vital:73013 , ISBN 978-3-030-93072-1 , https://doi.org/10.1007/978-3-030-93072-1_11
- Description: Urbanization is one of the major social changes sweeping the globe, with rapid growth of the urban population and stagnating growth of the rural population, especially in developing regions (UN-Habitat, 2020). In subSaharan Africa, rapid urbanization and poverty are the major fundamental development challenges that are perpetuating and deepening the crisis of food and nutrition insecurity in urban areas (Battersby, 2012). Many people living in urban areas face under-nutrition, mainly due to their lack of income rather than to a lack of capacity to produce food (Satterthwaite et al., 2010). The health and nutritional status of urban populations with very low incomes are at risk from rising prices in staple foods. This became evident with the rising hunger among urban populations after the food price rises in 2007 and the first half of 2008 (Cohen and Garrett, 2009). In South Africa, poverty, unemployment and high food prices are dominant and influence dietary change, which subsequently increases urban food insecurity and malnutrition (Battersby, 2012).
- Full Text:
How many people globally actually use non-timber forest products?
- Shackleton, Charlie M, de Vos, Alta
- Authors: Shackleton, Charlie M , de Vos, Alta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403200 , vital:69933 , xlink:href="https://doi.org/10.1016/j.forpol.2021.102659"
- Description: Non-timber forest products (NTFPs) are widely used wild, biological products harvested from rural and urban landscapes for household subsistence, income and culture, thereby contributing to human wellbeing. Estimates of the numbers of people making use of, or being dependent on, NTFPs vary widely, and global estimates to date have excluded urban populations and also NTFP users in the Global North. Additionally, most global or continental estimates are two or more decades old, and hence do not account for significant worldwide changes in societies, cultures, economies and landscapes since the estimates were made. Here we collate more recent empirical studies reporting the number of NTFP users at fine scales that we extrapolate up for three broad regions, viz. rural areas of the Global South, urban areas of the Global South, and the Global North, as the basis for estimating the number of NTFP users globally. We calculate the lower and upper bounds, as well a median estimate. We find the lowest and median approximations to be 3.5 billion and 5.76 billion users globally, respectively, based on conservative approaches. This is more than double and triple, respectively, the oft cited and dated figure of 1.6 billion. Moreover, we find that only half of the global NTFP users are located in rural regions of the Global South, and that the other half are in urban areas and the Global North, showing that NTFPs are of importance across socio-economic and geographic regions, not just in remote and underdeveloped villages of the Global South. With such large numbers of users around the world, it is imperative that the supply, management, conservation and safeguarding of the values of NTFPs take a more central place in sectoral and development policies.
- Full Text:
- Authors: Shackleton, Charlie M , de Vos, Alta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/403200 , vital:69933 , xlink:href="https://doi.org/10.1016/j.forpol.2021.102659"
- Description: Non-timber forest products (NTFPs) are widely used wild, biological products harvested from rural and urban landscapes for household subsistence, income and culture, thereby contributing to human wellbeing. Estimates of the numbers of people making use of, or being dependent on, NTFPs vary widely, and global estimates to date have excluded urban populations and also NTFP users in the Global North. Additionally, most global or continental estimates are two or more decades old, and hence do not account for significant worldwide changes in societies, cultures, economies and landscapes since the estimates were made. Here we collate more recent empirical studies reporting the number of NTFP users at fine scales that we extrapolate up for three broad regions, viz. rural areas of the Global South, urban areas of the Global South, and the Global North, as the basis for estimating the number of NTFP users globally. We calculate the lower and upper bounds, as well a median estimate. We find the lowest and median approximations to be 3.5 billion and 5.76 billion users globally, respectively, based on conservative approaches. This is more than double and triple, respectively, the oft cited and dated figure of 1.6 billion. Moreover, we find that only half of the global NTFP users are located in rural regions of the Global South, and that the other half are in urban areas and the Global North, showing that NTFPs are of importance across socio-economic and geographic regions, not just in remote and underdeveloped villages of the Global South. With such large numbers of users around the world, it is imperative that the supply, management, conservation and safeguarding of the values of NTFPs take a more central place in sectoral and development policies.
- Full Text:
How the Teaching Development Grant was used (and the problem of common-sense understandings of teaching and learning)
- Moyo, Temwa, McKenna, Sioux, Ndebele, Clever
- Authors: Moyo, Temwa , McKenna, Sioux , Ndebele, Clever
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426917 , vital:72400 , xlink:href="http://dx.doi.org/10.17159/2520-9868/i86a07"
- Description: Teachers at primary and secondary education levels are required to hold a professional qualification but, at the higher education level, all that is required is content expertise. This may well contribute to South Africa's low university throughput and retention rates, in response to which, since 2004, the state has provided ZAR5.5 billion in the form of the Teaching Development Grant (now the University Capacity Development Grant) to address poor completion rates. We present an analysis of the use of the grant across the sector using a social realist framework. Every academic and student has themselves been taught and so have developed untheorised assumptions about curriculum and pedagogy. Such common-sense assumptions about teaching and learning often serve to reinforce the status quo, which is particularly problematic in a sector with poor and racially differentiated throughput and success rates. Many initiatives funded through the grant evidenced a reliance on common-sense assumptions rather than on theorised accounts. In particular, student development often took the form of remedial, add-on initiatives that left the mainstream curriculum untouched-and staff development was often generic and short term. We also found that expertise in academic development, which could potentially challenge common-sense assumptions, was unevenly distributed.
- Full Text:
- Authors: Moyo, Temwa , McKenna, Sioux , Ndebele, Clever
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426917 , vital:72400 , xlink:href="http://dx.doi.org/10.17159/2520-9868/i86a07"
- Description: Teachers at primary and secondary education levels are required to hold a professional qualification but, at the higher education level, all that is required is content expertise. This may well contribute to South Africa's low university throughput and retention rates, in response to which, since 2004, the state has provided ZAR5.5 billion in the form of the Teaching Development Grant (now the University Capacity Development Grant) to address poor completion rates. We present an analysis of the use of the grant across the sector using a social realist framework. Every academic and student has themselves been taught and so have developed untheorised assumptions about curriculum and pedagogy. Such common-sense assumptions about teaching and learning often serve to reinforce the status quo, which is particularly problematic in a sector with poor and racially differentiated throughput and success rates. Many initiatives funded through the grant evidenced a reliance on common-sense assumptions rather than on theorised accounts. In particular, student development often took the form of remedial, add-on initiatives that left the mainstream curriculum untouched-and staff development was often generic and short term. We also found that expertise in academic development, which could potentially challenge common-sense assumptions, was unevenly distributed.
- Full Text:
Hybrid approaches to teaching: Re-imagining the teaching of a foundational science course during a global pandemic
- Parker, Daniel M, Vorster, Jo-Anne E, Quinn, Lynn, Blackie, Margaret A L
- Authors: Parker, Daniel M , Vorster, Jo-Anne E , Quinn, Lynn , Blackie, Margaret A L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426662 , vital:72377 , xlink:href="https://www.ajol.info/index.php/cristal/article/view/240803"
- Description: Access to scientific knowledge, and teaching in the sciences, is believed to be about training because scientific knowledge is, generally, specialised. However, for students to gain full epistemological access in the sciences, they also need to be inducted as scientists and learners of science. We use Bernstein’s regulative and instructional discourse to engage with the notion of epistemological access and effectiveness of a foundational science course. We examine how the course can cultivate scientific identities amongst first year students at a recently established South African university. Our analysis assesses the impact of the forced shift from contact teaching to Emergency Remote Teaching due to the COVID-19 pandemic. We demonstrate that the course was able to begin to facilitate the cultivation of different kinds of knowers in science. However, several gaps remain. Thus, we argue that foundational science lecturers should focus on hybrid teaching approaches to promote enhanced learning amongst students.
- Full Text:
- Authors: Parker, Daniel M , Vorster, Jo-Anne E , Quinn, Lynn , Blackie, Margaret A L
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426662 , vital:72377 , xlink:href="https://www.ajol.info/index.php/cristal/article/view/240803"
- Description: Access to scientific knowledge, and teaching in the sciences, is believed to be about training because scientific knowledge is, generally, specialised. However, for students to gain full epistemological access in the sciences, they also need to be inducted as scientists and learners of science. We use Bernstein’s regulative and instructional discourse to engage with the notion of epistemological access and effectiveness of a foundational science course. We examine how the course can cultivate scientific identities amongst first year students at a recently established South African university. Our analysis assesses the impact of the forced shift from contact teaching to Emergency Remote Teaching due to the COVID-19 pandemic. We demonstrate that the course was able to begin to facilitate the cultivation of different kinds of knowers in science. However, several gaps remain. Thus, we argue that foundational science lecturers should focus on hybrid teaching approaches to promote enhanced learning amongst students.
- Full Text:
IFRS and FPI nexus: does the quality of the institutional framework matter for African countries?
- Simbi, Chipo, Arendse, Jacqueline A, Khumalo, Sibanisezwe A
- Authors: Simbi, Chipo , Arendse, Jacqueline A , Khumalo, Sibanisezwe A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426448 , vital:72354 , xlink:href="https://doi.org/10.1108/JAEE-10-2021-0319"
- Description: The institutional framework of an African country may influence the effectiveness of the International Financial Reporting Standards (IFRS) on foreign investment inflows. The purpose of this paper is to argue that the quality of a country's institutional framework impacts the effectiveness of IFRS to an adopting country and ultimately influences the levels of Foreign Portfolio Investment (FPI).
- Full Text:
- Authors: Simbi, Chipo , Arendse, Jacqueline A , Khumalo, Sibanisezwe A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426448 , vital:72354 , xlink:href="https://doi.org/10.1108/JAEE-10-2021-0319"
- Description: The institutional framework of an African country may influence the effectiveness of the International Financial Reporting Standards (IFRS) on foreign investment inflows. The purpose of this paper is to argue that the quality of a country's institutional framework impacts the effectiveness of IFRS to an adopting country and ultimately influences the levels of Foreign Portfolio Investment (FPI).
- Full Text:
Impedimetric aptasensor for HER2 biomarker using graphene quantum dots, polypyrrole and cobalt phthalocyanine modified electrodes
- Centane, Sixolile, Nyokong, Tebello
- Authors: Centane, Sixolile , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230960 , vital:49836 , xlink:href="https://doi.org/10.1016/j.sbsr.2021.100467"
- Description: A method is presented for the electrochemical detection of the breast cancer biomarker human epidermal growth factor receptor 2 (HER2). A glassy carbon electrode was modified using two techniques known as sequential adsorption and electro-polymerization, and the results are compared. The highly conductive polypyrrole (PPy) is used, in the presence of sulfur/nitrogen doped graphene quantum dots (SNGQDs) and a known cobalt phthalocyanine (CoPc). The different nanomaterials were used as an immobilization platform for the HER2 specific HB5 aptamer via amide linkage. The nanomaterials were arranged in various ways on the glassy carbon electrode, to investigate the effect of the electrode interface on the operational characteristics of a biosensor. The immobilized aptamer selectively recognizes HER2 on the electrode interface, and this leads to an increased charge transfer resistance (Rct) of the electrode when using ferricyanide as the electrochemical probe. The developed immunosensors showed high sensitivity with the best detection limit of 0.00141 ng/mL. The results showed that the method is simple and sensitive enough for the determination of HER2 in serum samples with good reproducibility and accuracy.
- Full Text:
- Authors: Centane, Sixolile , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/230960 , vital:49836 , xlink:href="https://doi.org/10.1016/j.sbsr.2021.100467"
- Description: A method is presented for the electrochemical detection of the breast cancer biomarker human epidermal growth factor receptor 2 (HER2). A glassy carbon electrode was modified using two techniques known as sequential adsorption and electro-polymerization, and the results are compared. The highly conductive polypyrrole (PPy) is used, in the presence of sulfur/nitrogen doped graphene quantum dots (SNGQDs) and a known cobalt phthalocyanine (CoPc). The different nanomaterials were used as an immobilization platform for the HER2 specific HB5 aptamer via amide linkage. The nanomaterials were arranged in various ways on the glassy carbon electrode, to investigate the effect of the electrode interface on the operational characteristics of a biosensor. The immobilized aptamer selectively recognizes HER2 on the electrode interface, and this leads to an increased charge transfer resistance (Rct) of the electrode when using ferricyanide as the electrochemical probe. The developed immunosensors showed high sensitivity with the best detection limit of 0.00141 ng/mL. The results showed that the method is simple and sensitive enough for the determination of HER2 in serum samples with good reproducibility and accuracy.
- Full Text:
Improving the mental health of women intimate partner violence survivors: Findings from a realist review of psychosocial interventions
- Paphitis, Sharli A, Bentley, Abigail, Asher, Laura, Osrin, David, Oram, Sian
- Authors: Paphitis, Sharli A , Bentley, Abigail , Asher, Laura , Osrin, David , Oram, Sian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426453 , vital:72355 , xlink:href="https://doi.org/10.1371/journal.pone.0264845"
- Description: Intimate partner violence (IPV) is highly prevalent and is associated with a range of mental health problems. A broad range of psychosocial interventions have been developed to support the recovery of women survivors of IPV, but their mechanisms of action remain unclear.
- Full Text:
- Authors: Paphitis, Sharli A , Bentley, Abigail , Asher, Laura , Osrin, David , Oram, Sian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426453 , vital:72355 , xlink:href="https://doi.org/10.1371/journal.pone.0264845"
- Description: Intimate partner violence (IPV) is highly prevalent and is associated with a range of mental health problems. A broad range of psychosocial interventions have been developed to support the recovery of women survivors of IPV, but their mechanisms of action remain unclear.
- Full Text:
In vitro photoinactivation of S. aureus and photocatalytic degradation of tetracycline by novel phthalocyanine-graphene quantum dots nano-assemblies
- Openda, Yolande Ikala, Mgidlana, Sithi, Nyokong, Tebello
- Authors: Openda, Yolande Ikala , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229895 , vital:49721 , xlink:href="https://doi.org/10.1016/j.jlumin.2022.118863"
- Description: A novel asymmetrical zinc (II) phthalocyanine (Pc) 4 bearing three dimethoxy groups and one carboxyl group was linked to glutathione capped graphene quantum dots (GQDs) by the reaction of carboxylic acid substituent on Pc 4 with the amino group on the GQDs. On the other side, the symmetrical Pc analog 3 was linked to the same nanoparticles through π-π interactions. The as-formed nano-photosensitizers were fully characterized by spectroscopic methods and their photophysicochemical properties were investigated as well. Photodynamic antimicrobial chemotherapy was performed on the planktonic cells of S. aureus strain. And the results show that these nano assemblies were able to completely inhibit the metabolic activity of the resistant bacteria strain S. aureus with a 10.26 log reduction in the viable count. Again, asymmetrical Pc showed higher photocatalytic activity compared to the symmetrical complex with higher kobs and fast initial rates for the former. The photocatalysis obeyed the Langmuir-Hinshelwood kinetic model. The target conjugates showed all the advantages of two different groups existing on a single entity.
- Full Text:
- Authors: Openda, Yolande Ikala , Mgidlana, Sithi , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229895 , vital:49721 , xlink:href="https://doi.org/10.1016/j.jlumin.2022.118863"
- Description: A novel asymmetrical zinc (II) phthalocyanine (Pc) 4 bearing three dimethoxy groups and one carboxyl group was linked to glutathione capped graphene quantum dots (GQDs) by the reaction of carboxylic acid substituent on Pc 4 with the amino group on the GQDs. On the other side, the symmetrical Pc analog 3 was linked to the same nanoparticles through π-π interactions. The as-formed nano-photosensitizers were fully characterized by spectroscopic methods and their photophysicochemical properties were investigated as well. Photodynamic antimicrobial chemotherapy was performed on the planktonic cells of S. aureus strain. And the results show that these nano assemblies were able to completely inhibit the metabolic activity of the resistant bacteria strain S. aureus with a 10.26 log reduction in the viable count. Again, asymmetrical Pc showed higher photocatalytic activity compared to the symmetrical complex with higher kobs and fast initial rates for the former. The photocatalysis obeyed the Langmuir-Hinshelwood kinetic model. The target conjugates showed all the advantages of two different groups existing on a single entity.
- Full Text:
Indium phthalocyanines
- Pinar, Sen, Mack, John, Nyokong, Tebello
- Authors: Pinar, Sen , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229998 , vital:49731 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.131850"
- Description: In this study, the photodynamic antimicrobial activities of a series of new tetra-substituted indium phthalocyanine (InPc) complexes are assessed. An aldehyde substituted complex (2) was initially prepared, which was converted through a condensatioreaction to an imine-pyrrolidine substituted complex (3), which in turn was quaternized to form a tetracationic species (4). Favorable photophysicochemical properties were obtained by incorporating a heavy In(III) ion into the central cavity. Aggregation studies revealed that 2–4 remain non-aggregated in DMSO at concentration below 25 µM. The photodeactivation of S.aureus and E.coli was studied. Log reduction values > 9.0 were obtained for cationic InPc 4 after 30 min of incubation and exposure to light for 75 min.
- Full Text:
- Authors: Pinar, Sen , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229998 , vital:49731 , xlink:href="https://doi.org/10.1016/j.molstruc.2021.131850"
- Description: In this study, the photodynamic antimicrobial activities of a series of new tetra-substituted indium phthalocyanine (InPc) complexes are assessed. An aldehyde substituted complex (2) was initially prepared, which was converted through a condensatioreaction to an imine-pyrrolidine substituted complex (3), which in turn was quaternized to form a tetracationic species (4). Favorable photophysicochemical properties were obtained by incorporating a heavy In(III) ion into the central cavity. Aggregation studies revealed that 2–4 remain non-aggregated in DMSO at concentration below 25 µM. The photodeactivation of S.aureus and E.coli was studied. Log reduction values > 9.0 were obtained for cationic InPc 4 after 30 min of incubation and exposure to light for 75 min.
- Full Text:
Insights into the Dynamics and Binding of Two Polyprotein Substrate Cleavage Points in the Context of the SARS-CoV-2 Main and Papain-like Proteases
- Sanusi, Zainab K, Lobb, Kevin A
- Authors: Sanusi, Zainab K , Lobb, Kevin A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452773 , vital:75169 , xlink:href="https://doi.org/10.3390/molecules27238251"
- Description: It is well known that vital enzymes in the replication process of the coronavirus are the SARS-CoV-2 PLpro and SARS-CoV-2 3CLpro, both of which are important targets in the search for anti-coronavirus agents. These two enzymes are responsible for cleavage at various polyprotein sites in the SARS-CoV-2 lifecycle. Herein, the dynamics of the polyprotein cleavage sequences for the boundary between non-structural proteins Nsp1 and Nsp2 (CS1) and between Nsp2 and Nsp3 (CS2) in complex with both the papain-like protein PLpro and the main protease 3CLpro were explored using computational methods. The post dynamics analysis reveals that CS1 and CS2 both have greater stability when complexed with PLpro. Of these two, greater stability is observed for the CS1–PLpro complex, while destabilization resulting in loss of CS2 from the PLpro active site is observed for CS2-PLpro, suggesting the rate of exchange by the papain-like protease is faster for CS2 compared to CS1. On the other hand, the 3CLpro main protease also reveals stability for CS1 suggesting that the main protease could also play a potential role in the cleavage at point CS1. However, destabilization occurs early in the simulation for the complex CLpro–CS2 suggesting a poor interaction and non-plausible protease cleavage of the polyprotein at CS2 by the main protease. These findings could be used as a guide in the development and design of potent COVID-19 antiviral inhibitors that mimic the CS1 cleavage site.
- Full Text:
- Authors: Sanusi, Zainab K , Lobb, Kevin A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452773 , vital:75169 , xlink:href="https://doi.org/10.3390/molecules27238251"
- Description: It is well known that vital enzymes in the replication process of the coronavirus are the SARS-CoV-2 PLpro and SARS-CoV-2 3CLpro, both of which are important targets in the search for anti-coronavirus agents. These two enzymes are responsible for cleavage at various polyprotein sites in the SARS-CoV-2 lifecycle. Herein, the dynamics of the polyprotein cleavage sequences for the boundary between non-structural proteins Nsp1 and Nsp2 (CS1) and between Nsp2 and Nsp3 (CS2) in complex with both the papain-like protein PLpro and the main protease 3CLpro were explored using computational methods. The post dynamics analysis reveals that CS1 and CS2 both have greater stability when complexed with PLpro. Of these two, greater stability is observed for the CS1–PLpro complex, while destabilization resulting in loss of CS2 from the PLpro active site is observed for CS2-PLpro, suggesting the rate of exchange by the papain-like protease is faster for CS2 compared to CS1. On the other hand, the 3CLpro main protease also reveals stability for CS1 suggesting that the main protease could also play a potential role in the cleavage at point CS1. However, destabilization occurs early in the simulation for the complex CLpro–CS2 suggesting a poor interaction and non-plausible protease cleavage of the polyprotein at CS2 by the main protease. These findings could be used as a guide in the development and design of potent COVID-19 antiviral inhibitors that mimic the CS1 cleavage site.
- Full Text:
Integrated photocatalyst adsorbents based on porphyrin anchored to activated carbon granules for water treatment
- Oyim, James, Amuhaya, Edith K, Matshitse, Refilwe, Mack, John, Nyokong, Tebello
- Authors: Oyim, James , Amuhaya, Edith K , Matshitse, Refilwe , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300101 , vital:57893 , xlink:href="https://doi.org/10.1016/j.cartre.2022.100191"
- Description: Integration of adsorption and photocatalysis processes can lead to several benefits in water treatment. Integrating well-known adsorbents with photocatalysts ensures that all the interesting components are preserved and helps to overcome the serious downsides of each material and technique when operated independently. In this work, we introduce a new concept of combining both absorption and photodegradation mechanisms using organic photocatalytic adsorbents for water purification. This was achieved by formulating photosensitizing hybrids based on a newly synthesized chloroindium (III) 5,10,15,20-tetrakis(4-acetamidophenyl) porphyrin (InTAAP) compound, anchored on oxygen functionalized coconut shell-based activated carbon granules supports. The fashioned integrated photocatalyst adsorbent hybrid (InTAAP(ACO)) was then studied for their adsorption and photodegradation efficiency using methylene blue dye, where InTAAP(ACO) showed excellent photocatalytic activity compared to ACO and unfunctionalized activated carbon granules (AC), with appreciably high and adsorption properties as AC and ACO.
- Full Text:
- Authors: Oyim, James , Amuhaya, Edith K , Matshitse, Refilwe , Mack, John , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/300101 , vital:57893 , xlink:href="https://doi.org/10.1016/j.cartre.2022.100191"
- Description: Integration of adsorption and photocatalysis processes can lead to several benefits in water treatment. Integrating well-known adsorbents with photocatalysts ensures that all the interesting components are preserved and helps to overcome the serious downsides of each material and technique when operated independently. In this work, we introduce a new concept of combining both absorption and photodegradation mechanisms using organic photocatalytic adsorbents for water purification. This was achieved by formulating photosensitizing hybrids based on a newly synthesized chloroindium (III) 5,10,15,20-tetrakis(4-acetamidophenyl) porphyrin (InTAAP) compound, anchored on oxygen functionalized coconut shell-based activated carbon granules supports. The fashioned integrated photocatalyst adsorbent hybrid (InTAAP(ACO)) was then studied for their adsorption and photodegradation efficiency using methylene blue dye, where InTAAP(ACO) showed excellent photocatalytic activity compared to ACO and unfunctionalized activated carbon granules (AC), with appreciably high and adsorption properties as AC and ACO.
- Full Text:
Integrating child rights standards in contraceptive and abortion care for minors in Africa
- Kangaude, Godfrey D, Macleod, Catriona I, Coast, Ernestina, Fetters, Tamara
- Authors: Kangaude, Godfrey D , Macleod, Catriona I , Coast, Ernestina , Fetters, Tamara
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441242 , vital:73869 , xlink:href="https://doi.org/10.1002/ijgo.14502"
- Description: Minor girls in Africa face challenges in accessing high-quality contraceptive and abortion services because laws and policies are not child-friendly. Many countries maintain restrictive laws, policies, or hospital practices that make it difficult for minors to access contraception and safe abortion even when the pregnancy would risk their life or health. Further, the clinical guidelines on contraceptive and abortion care are silent, vague, or ambiguous regarding minors' consent. African states should remedy the situation by ensuring that clinical guidelines integrate child rights principles and standards articulated in child rights treaties to enable health providers to facilitate full, unencumbered access to contraceptive and abortion care for minor girls. A sample of clinical guidelines is analyzed to demonstrate the importance of explicit, consistent, and unambiguous language about children's consent to ensure that healthcare workers provide sexual and reproductive health care in a manner that respects child rights.
- Full Text:
- Authors: Kangaude, Godfrey D , Macleod, Catriona I , Coast, Ernestina , Fetters, Tamara
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441242 , vital:73869 , xlink:href="https://doi.org/10.1002/ijgo.14502"
- Description: Minor girls in Africa face challenges in accessing high-quality contraceptive and abortion services because laws and policies are not child-friendly. Many countries maintain restrictive laws, policies, or hospital practices that make it difficult for minors to access contraception and safe abortion even when the pregnancy would risk their life or health. Further, the clinical guidelines on contraceptive and abortion care are silent, vague, or ambiguous regarding minors' consent. African states should remedy the situation by ensuring that clinical guidelines integrate child rights principles and standards articulated in child rights treaties to enable health providers to facilitate full, unencumbered access to contraceptive and abortion care for minor girls. A sample of clinical guidelines is analyzed to demonstrate the importance of explicit, consistent, and unambiguous language about children's consent to ensure that healthcare workers provide sexual and reproductive health care in a manner that respects child rights.
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Interaction between an entomopathogenic fungus and entomopathogenic nematodes for increased mortality of Thaumatotibia leucotreta (Lepidoptera: Tortricidae)
- Prinsloo, Sandra, Hill, Martin P, Moore, Sean D, Malan, Antoinette P, Coombes, Candice A
- Authors: Prinsloo, Sandra , Hill, Martin P , Moore, Sean D , Malan, Antoinette P , Coombes, Candice A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417738 , vital:71482 , xlink:href="https://doi.org/10.1080/09583157.2022.2099528"
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a major phytosanitary pest of citrus in South Africa. Although several management tools exist, control options registered for use against the soil-dwelling life stages are limited. Both entomopathogenic nematodes (EPNs) and entomopathogenic fungi have been investigated previously, but they have not been studied in combination against T. leucotreta. Thus, this study investigated the interaction of an indigenous entomopathogenic fungus, Metarhizium pinghaense (previously anisopliae) FCM Ar 23 B3 with three indigenous EPNs: Steinernema yirgalemense 157-C, S. jeffreyense J194 and Heterorhabditis noenieputensis 158-C for increased late instar T. leucotreta larval mortality. Before interaction experiments, lethal concentration (LC) values for each of these microbial agents were determined through dose–response bioassays. Heterorhabditis noenieputensis recorded the highest LC50 amongst the nematodes (7.11 IJs/50 µl). Using the pre-determined LC70 value of M. pinghaense and the LC50 values for each of the nematode species, interaction experiments were conducted. Combinations of the nematodes either applied simultaneously with the fungus or at 24, 48, 72 or 96 h post-fungal application showed predominantly additive interactions. Synergy between the simultaneous application of S. yirgalemense and M. pinghaense was found, whilst the interaction between H. noenieputensis and M. pinghaense applied simultaneously and S. jeffreyense applied 24 h post-fungal application, recorded antagonistic interactions. The use of these agents in combination may therefore have the potential to increase control of T. leucotreta soil-dwelling life stages in citrus orchards across South Africa and should be further investigated.
- Full Text:
- Authors: Prinsloo, Sandra , Hill, Martin P , Moore, Sean D , Malan, Antoinette P , Coombes, Candice A
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417738 , vital:71482 , xlink:href="https://doi.org/10.1080/09583157.2022.2099528"
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a major phytosanitary pest of citrus in South Africa. Although several management tools exist, control options registered for use against the soil-dwelling life stages are limited. Both entomopathogenic nematodes (EPNs) and entomopathogenic fungi have been investigated previously, but they have not been studied in combination against T. leucotreta. Thus, this study investigated the interaction of an indigenous entomopathogenic fungus, Metarhizium pinghaense (previously anisopliae) FCM Ar 23 B3 with three indigenous EPNs: Steinernema yirgalemense 157-C, S. jeffreyense J194 and Heterorhabditis noenieputensis 158-C for increased late instar T. leucotreta larval mortality. Before interaction experiments, lethal concentration (LC) values for each of these microbial agents were determined through dose–response bioassays. Heterorhabditis noenieputensis recorded the highest LC50 amongst the nematodes (7.11 IJs/50 µl). Using the pre-determined LC70 value of M. pinghaense and the LC50 values for each of the nematode species, interaction experiments were conducted. Combinations of the nematodes either applied simultaneously with the fungus or at 24, 48, 72 or 96 h post-fungal application showed predominantly additive interactions. Synergy between the simultaneous application of S. yirgalemense and M. pinghaense was found, whilst the interaction between H. noenieputensis and M. pinghaense applied simultaneously and S. jeffreyense applied 24 h post-fungal application, recorded antagonistic interactions. The use of these agents in combination may therefore have the potential to increase control of T. leucotreta soil-dwelling life stages in citrus orchards across South Africa and should be further investigated.
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Interdisciplinarity requires careful stewardship of powerful knowledge
- Authors: McKenna, Sioux , de Bie G J
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434487 , vital:73068 , ISBN 9780367518707 , https://www.routledge.com/Enhancing-Science-Education-Exploring-Knowledge-Practices-with-Legitimation/Blackie-Adendorff-Mouton/p/book/9780367518707#:~:text=The%20book%20introduces%20Legitimation%20Code,grasp%20difficult%20and%20dense%20concepts
- Description: This book helps meet an urgent need for theorized, accessible and discipline-sensitive publications to assist science, technology, engineering and mathematics educators. The book introduces Legitimation Code Theory (LCT) and demonstrates how it can be used to improve teaching and learning in tertiary courses across the sciences. LCT provides a suite of tools which science educators can employ in order to help their students grasp difficult and dense concepts. The chapters cover a broad range of subjects, including biology, physics, chemistry and mathematics, as well as different curriculum, pedagogy and assessment practices. This is a crucial resource for any science educator who wants to better understand and improve their teaching.
- Full Text:
- Authors: McKenna, Sioux , de Bie G J
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434487 , vital:73068 , ISBN 9780367518707 , https://www.routledge.com/Enhancing-Science-Education-Exploring-Knowledge-Practices-with-Legitimation/Blackie-Adendorff-Mouton/p/book/9780367518707#:~:text=The%20book%20introduces%20Legitimation%20Code,grasp%20difficult%20and%20dense%20concepts
- Description: This book helps meet an urgent need for theorized, accessible and discipline-sensitive publications to assist science, technology, engineering and mathematics educators. The book introduces Legitimation Code Theory (LCT) and demonstrates how it can be used to improve teaching and learning in tertiary courses across the sciences. LCT provides a suite of tools which science educators can employ in order to help their students grasp difficult and dense concepts. The chapters cover a broad range of subjects, including biology, physics, chemistry and mathematics, as well as different curriculum, pedagogy and assessment practices. This is a crucial resource for any science educator who wants to better understand and improve their teaching.
- Full Text:
Invasive alien aquatic plant species management drives aquatic ecosystem community recovery: An exploration using stable isotope analysis
- Motitsoe, Samuel N, Hill, Jaclyn M, Coetzee, Julie A, Hill, Martin P
- Authors: Motitsoe, Samuel N , Hill, Jaclyn M , Coetzee, Julie A , Hill, Martin P
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423527 , vital:72069 , xlink:href="https://doi.org/10.1016/j.biocontrol.2022.104995"
- Description: The socio-economic and ecological impacts of invasive alien aquatic plant (IAAP) species have been well studied globally. However less is known about ecosystem recovery following the management of IAAP species. This study employed a before-after study design to investigate ecological recovery following the management of Salvinia molesta D.S. Mitchell, at four field sites in South Africa. We hypothesized that the presence of S. molesta would have a negative impact on the ecosystem food web structure, and that following S. molesta control, the systems would show positive ecosystem recovery. Aquatic macroinvertebrate and macrophyte samples collected before and after mechanical or biological control of S. molesta, were analysed for δ13C and δ15N stable isotopes. Salvinia molesta infestations negatively impacted the food web structure, indicated by reduced food chain length, trophic diversity and basal resources. This represented an altered aquatic food web structure, that in some cases, led to the collapse of the aquatic community. In contrast, after either mechanical or biological control, there were increases in food chain length, trophic diversity and abundance of energy resources accessed by consumers, indicating improved food web structure. Although the study showed positive ecosystem recovery following control, we noted that each control method followed a different recovery trajectory. We conclude that S. molesta invasions reduce aquatic biodiversity and alter ecosystem trophic dynamics and related ecosystem processes, necessitating control.
- Full Text:
- Authors: Motitsoe, Samuel N , Hill, Jaclyn M , Coetzee, Julie A , Hill, Martin P
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423527 , vital:72069 , xlink:href="https://doi.org/10.1016/j.biocontrol.2022.104995"
- Description: The socio-economic and ecological impacts of invasive alien aquatic plant (IAAP) species have been well studied globally. However less is known about ecosystem recovery following the management of IAAP species. This study employed a before-after study design to investigate ecological recovery following the management of Salvinia molesta D.S. Mitchell, at four field sites in South Africa. We hypothesized that the presence of S. molesta would have a negative impact on the ecosystem food web structure, and that following S. molesta control, the systems would show positive ecosystem recovery. Aquatic macroinvertebrate and macrophyte samples collected before and after mechanical or biological control of S. molesta, were analysed for δ13C and δ15N stable isotopes. Salvinia molesta infestations negatively impacted the food web structure, indicated by reduced food chain length, trophic diversity and basal resources. This represented an altered aquatic food web structure, that in some cases, led to the collapse of the aquatic community. In contrast, after either mechanical or biological control, there were increases in food chain length, trophic diversity and abundance of energy resources accessed by consumers, indicating improved food web structure. Although the study showed positive ecosystem recovery following control, we noted that each control method followed a different recovery trajectory. We conclude that S. molesta invasions reduce aquatic biodiversity and alter ecosystem trophic dynamics and related ecosystem processes, necessitating control.
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Is education blithely producing unemployed graduates?: A reflection based on a review of environmental skills initiatives 2016-2021
- Authors: Rosenberg, Eureta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370619 , vital:66360 , xlink:href="http://dx.doi.org/10.17159/2520-9868/i89a08"
- Description: A statement from the president of the Black Business Council (BBC) that "our education system continues to produce the unemployed graduates" (NewZRoomAfrika, 2021) because "the courses they are doing are not required by industry" reflects the perennial perception that South Africa's education system is a cause of unemployment. In this paper, I explore aspects of this perception through a meta-review of environmental skills-related studies conducted over the past five years. Data used in these studies include graduation trends based on higher education, employer surveys, analyses of skills needs in the workplace compared to courses offered, and case examples of internships and teacher development. Using an ecological-systems model, I relate the findings, in a layered critical realist analysis, to the socio-cultural milieu in South Africa. I challenge the conception of relevant graduate education evident in the BBC's statement.
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- Authors: Rosenberg, Eureta
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370619 , vital:66360 , xlink:href="http://dx.doi.org/10.17159/2520-9868/i89a08"
- Description: A statement from the president of the Black Business Council (BBC) that "our education system continues to produce the unemployed graduates" (NewZRoomAfrika, 2021) because "the courses they are doing are not required by industry" reflects the perennial perception that South Africa's education system is a cause of unemployment. In this paper, I explore aspects of this perception through a meta-review of environmental skills-related studies conducted over the past five years. Data used in these studies include graduation trends based on higher education, employer surveys, analyses of skills needs in the workplace compared to courses offered, and case examples of internships and teacher development. Using an ecological-systems model, I relate the findings, in a layered critical realist analysis, to the socio-cultural milieu in South Africa. I challenge the conception of relevant graduate education evident in the BBC's statement.
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Is green space associated with reduced crime? A national-scale study from the Global South
- Venter, Zander S, Shackleton, Charlie M, Faull, Andrew, Lancaster, Lizette, Breetzke, Gregory, Edelstein, Ian
- Authors: Venter, Zander S , Shackleton, Charlie M , Faull, Andrew , Lancaster, Lizette , Breetzke, Gregory , Edelstein, Ian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402340 , vital:69843 , xlink:href="https://doi.org/10.1016/j.scitotenv.2022.154005"
- Description: Assumptions about the link between green space and crime mitigation are informed by literature that overwhelmingly originates in the Global North. Little is known about the association between green spaces and crime in the Global South. We utilized 10 years of precinct-level crime statistics (n = 1152) over South Africa, a global crime hotspot, to test the hypothesis that green space is associated with reduced crime rates. We found that, after controlling for a number of socio-demographic confounders (unemployment, income, age, education, land use and population density), for every 1% increase in total green space there is a 1.2% (0.7 to 1.7%; 95% confidence interval) decrease in violent crime, and 1.3% (0.8 to 1.8%) decrease in property crime, with no effect on sexual crimes. However, the direction of the association changed for property crimes when exploring the effect of green space characteristics including tree cover and park accessibility. Property crimes increase by 0.4% (0.1 to 0.7%) with a percentage increase in tree cover, and by 0.9% (0.5 to 1.3%) with every kilometer increase in proximity to a public park. Further research, including experimental studies, is needed to better isolate causal mechanisms behind crime-green space associations, especially considering that green space may map to race and income inequality and that there may be more crime reporting in affluent areas. Nevertheless, our results provide a complementary contribution to the evidence from the Global North, highlighting the need for more nuanced definitions of green space and its characteristics when considering links to crime. When viewed in light of the broader suite of ecosystem services provided by green space, our results support urban greening as a major strategy towards achieving just and sustainable cities and towns.
- Full Text:
- Authors: Venter, Zander S , Shackleton, Charlie M , Faull, Andrew , Lancaster, Lizette , Breetzke, Gregory , Edelstein, Ian
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/402340 , vital:69843 , xlink:href="https://doi.org/10.1016/j.scitotenv.2022.154005"
- Description: Assumptions about the link between green space and crime mitigation are informed by literature that overwhelmingly originates in the Global North. Little is known about the association between green spaces and crime in the Global South. We utilized 10 years of precinct-level crime statistics (n = 1152) over South Africa, a global crime hotspot, to test the hypothesis that green space is associated with reduced crime rates. We found that, after controlling for a number of socio-demographic confounders (unemployment, income, age, education, land use and population density), for every 1% increase in total green space there is a 1.2% (0.7 to 1.7%; 95% confidence interval) decrease in violent crime, and 1.3% (0.8 to 1.8%) decrease in property crime, with no effect on sexual crimes. However, the direction of the association changed for property crimes when exploring the effect of green space characteristics including tree cover and park accessibility. Property crimes increase by 0.4% (0.1 to 0.7%) with a percentage increase in tree cover, and by 0.9% (0.5 to 1.3%) with every kilometer increase in proximity to a public park. Further research, including experimental studies, is needed to better isolate causal mechanisms behind crime-green space associations, especially considering that green space may map to race and income inequality and that there may be more crime reporting in affluent areas. Nevertheless, our results provide a complementary contribution to the evidence from the Global North, highlighting the need for more nuanced definitions of green space and its characteristics when considering links to crime. When viewed in light of the broader suite of ecosystem services provided by green space, our results support urban greening as a major strategy towards achieving just and sustainable cities and towns.
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Is the instrumental approach a ‘silver bullet’for addressing non-compliance in recreational fisheries: A South African case study
- Bova, Christopher S, Stephens, Jed, Aswani, Shankar, Potts, Warren M
- Authors: Bova, Christopher S , Stephens, Jed , Aswani, Shankar , Potts, Warren M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391359 , vital:68644 , xlink:href="https://doi.org/10.1016/j.fishres.2022.106439"
- Description: Non-compliance with recreational fishery regulations is considered to be one of the biggest threats to the sustainability of fisheries. Dedicated non-compliance studies are seldom carried out at the national level which makes it difficult to discern the behavioural compliance norms within a population. The instrumental approach for compliance is the traditional paradigm in recreational fisheries. It postulates that increased enforcement activities and the corresponding punishment will improve compliance behaviour, although there is little empirical evidence for such a supposition within the recreational fisheries context. Using face-to-face encounter surveys employing the ballot box method for reducing social desirability bias (SDB), South African marine shore-based fishery (MSBF) participants were questioned on their compliance behaviour with a set of regulations pertaining to the fishery. Overall non-compliance levels were very high (52%), and non-compliance levels with individual regulations varied based on provincial locality. Perceptions and observations of enforcement activity had no significant impact on compliance behaviour. Participants that had previously been caught by law enforcement violating the regulations were still more likely to violate the regulations than participants that had not faced enforcement action. Results indicate that calls for increased enforcement as a means of improving compliance behaviour are questionable in the South African MSBF, and further emphasise the need to develop alternative approaches, such as those pertaining to normative theory, within recreational fisheries.
- Full Text:
- Authors: Bova, Christopher S , Stephens, Jed , Aswani, Shankar , Potts, Warren M
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/391359 , vital:68644 , xlink:href="https://doi.org/10.1016/j.fishres.2022.106439"
- Description: Non-compliance with recreational fishery regulations is considered to be one of the biggest threats to the sustainability of fisheries. Dedicated non-compliance studies are seldom carried out at the national level which makes it difficult to discern the behavioural compliance norms within a population. The instrumental approach for compliance is the traditional paradigm in recreational fisheries. It postulates that increased enforcement activities and the corresponding punishment will improve compliance behaviour, although there is little empirical evidence for such a supposition within the recreational fisheries context. Using face-to-face encounter surveys employing the ballot box method for reducing social desirability bias (SDB), South African marine shore-based fishery (MSBF) participants were questioned on their compliance behaviour with a set of regulations pertaining to the fishery. Overall non-compliance levels were very high (52%), and non-compliance levels with individual regulations varied based on provincial locality. Perceptions and observations of enforcement activity had no significant impact on compliance behaviour. Participants that had previously been caught by law enforcement violating the regulations were still more likely to violate the regulations than participants that had not faced enforcement action. Results indicate that calls for increased enforcement as a means of improving compliance behaviour are questionable in the South African MSBF, and further emphasise the need to develop alternative approaches, such as those pertaining to normative theory, within recreational fisheries.
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It's a numbers game: inundative biological control of water hyacinth (Pontederia crassipes), using Megamelus scutellaris (Hemiptera: Delphacidae) yields success at a high elevation, hypertrophic reservoir in South Africa
- Coetzee, Julie A, Miller, Benjamin E, Kinsler, David, Sebola, Keneilwe, Hill, Martin P
- Authors: Coetzee, Julie A , Miller, Benjamin E , Kinsler, David , Sebola, Keneilwe , Hill, Martin P
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417749 , vital:71483 , xlink:href="https://doi.org/10.1080/09583157.2022.2109594"
- Description: Classical biological control of water hyacinth in South Africa has been constrained by cool winter temperatures that limit population growth of the biological control agents, and highly eutrophic waters which enhance plant growth. However, inundative releases of the control agent, Megamelus scutellaris (Hemiptera: Delphacidae), at the Hartbeespoort Dam, South Africa, suggest that water hyacinth can be managed successfully using biological control as a standalone intervention for the first time in the absence of herbicide operations, despite eutrophication and a temperate climate. Sentinel-2 satellite images were used to measure the reduction in water hyacinth cover from over 37% to less than 6% over two consecutive years since M. scutellaris was first released on the dam in 2018, while site surveys confirmed a corresponding increase in M. scutellaris population density from fewer than 500 insects/m2 in October 2019, to more than 6000 insects/m2 by March 2020. Inundative release strategies are recommended for the control of water hyacinth in South Africa at key stages of its invasion, particularly after winter, and flooding events.
- Full Text:
- Authors: Coetzee, Julie A , Miller, Benjamin E , Kinsler, David , Sebola, Keneilwe , Hill, Martin P
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417749 , vital:71483 , xlink:href="https://doi.org/10.1080/09583157.2022.2109594"
- Description: Classical biological control of water hyacinth in South Africa has been constrained by cool winter temperatures that limit population growth of the biological control agents, and highly eutrophic waters which enhance plant growth. However, inundative releases of the control agent, Megamelus scutellaris (Hemiptera: Delphacidae), at the Hartbeespoort Dam, South Africa, suggest that water hyacinth can be managed successfully using biological control as a standalone intervention for the first time in the absence of herbicide operations, despite eutrophication and a temperate climate. Sentinel-2 satellite images were used to measure the reduction in water hyacinth cover from over 37% to less than 6% over two consecutive years since M. scutellaris was first released on the dam in 2018, while site surveys confirmed a corresponding increase in M. scutellaris population density from fewer than 500 insects/m2 in October 2019, to more than 6000 insects/m2 by March 2020. Inundative release strategies are recommended for the control of water hyacinth in South Africa at key stages of its invasion, particularly after winter, and flooding events.
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Key for the identification of third instar larvae of African blowflies (Diptera Calliphoridae) of forensic importance in death investigations
- Szpila, Krzysztof, Williams, Kirstin A, Soszyńska, Agnieszka, Ekanem, Mfon, Heyns, Marise, Dinka, Mergi D, Villet, Martin H
- Authors: Szpila, Krzysztof , Williams, Kirstin A , Soszyńska, Agnieszka , Ekanem, Mfon , Heyns, Marise , Dinka, Mergi D , Villet, Martin H
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440761 , vital:73810 , https://doi.org/10.1016/j.forsciint.2023.111889
- Description: Blowfly larvae are the insects primarily responsible for the active stage of decomposition of exposed vertebrate remains and are the most frequently collected entomological evidence during forensic investigations of death. The necrophagous calliphorids in continental Africa that consistently develop on large vertebrate carrion include 11 species belonging to four genera: Calliphora, Chrysomya, Hemipyrellia and Lucilia. Most of these species are widespread in Africa and frequently reported on large animal carcasses and carrion and human corpses. A few keys have been compiled for identification of their third instar larvae, but none of them covers the complete set of taxa. Therefore, we provide a new comprehensive key with original illustrations of all taxonomically significant characters. The key is based on characters that should be easily observable even in poorly equipped local laboratories and is a reliable taxonomic tool for material collected in either urban or rural areas where synanthropic species predominate. However, it should be used with some caution in areas with relatively pristine natural habitats, where additional carrion-breeding species may occur. The publication of the key will significantly facilitate both medical and forensic entomological research and practice in Africa.
- Full Text:
- Authors: Szpila, Krzysztof , Williams, Kirstin A , Soszyńska, Agnieszka , Ekanem, Mfon , Heyns, Marise , Dinka, Mergi D , Villet, Martin H
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440761 , vital:73810 , https://doi.org/10.1016/j.forsciint.2023.111889
- Description: Blowfly larvae are the insects primarily responsible for the active stage of decomposition of exposed vertebrate remains and are the most frequently collected entomological evidence during forensic investigations of death. The necrophagous calliphorids in continental Africa that consistently develop on large vertebrate carrion include 11 species belonging to four genera: Calliphora, Chrysomya, Hemipyrellia and Lucilia. Most of these species are widespread in Africa and frequently reported on large animal carcasses and carrion and human corpses. A few keys have been compiled for identification of their third instar larvae, but none of them covers the complete set of taxa. Therefore, we provide a new comprehensive key with original illustrations of all taxonomically significant characters. The key is based on characters that should be easily observable even in poorly equipped local laboratories and is a reliable taxonomic tool for material collected in either urban or rural areas where synanthropic species predominate. However, it should be used with some caution in areas with relatively pristine natural habitats, where additional carrion-breeding species may occur. The publication of the key will significantly facilitate both medical and forensic entomological research and practice in Africa.
- Full Text: