Conceptualising the more knowledgeable other within a multi-directional ZPD:
- Authors: Graven, Mellony
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69519 , vital:29545 , https://doi.org/10.1007/s10649-017-9768-1
- Description: From a Marxian/Vygotskian perspective, learning is social in origin and it happens in the presence of others that are more knowledgeable. Extending this view to the learning of mathematics, such learning also becomes inseparable from the presence of others (people and artefacts). Researchers over decades have studied different interactions to see how such learning with others occurs, what is the role of the (more knowledgeable) other, and if at all this role alternates between the participants. In this paper, we looked at a 5-year-old’s (Lila) interaction with her mother (Mellony) and a television remote control as Lila attempted to count in threes using the three by three physical layout of the numbered buttons 1–9 on the remote control. We specifically looked at the emergence of the Zone of Proximal Development (ZPD) as Lila’s attention was caught by the properties of the remote control and by her mother’s questions. We also pay attention to how the role of the more knowledgeable other alternates among the participants. Our findings suggest that Lila, at times, used resources provided by the physical properties of the remote control and sometimes, used resources provided by Mellony to think about the task of counting in threes. In Lila’s interaction, we interpreted a multi-directional ZPD as the role of the more knowledgeable other alternated between Mellony, Lila and the remote control.
- Full Text:
- Date Issued: 2009
- Authors: Graven, Mellony
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69519 , vital:29545 , https://doi.org/10.1007/s10649-017-9768-1
- Description: From a Marxian/Vygotskian perspective, learning is social in origin and it happens in the presence of others that are more knowledgeable. Extending this view to the learning of mathematics, such learning also becomes inseparable from the presence of others (people and artefacts). Researchers over decades have studied different interactions to see how such learning with others occurs, what is the role of the (more knowledgeable) other, and if at all this role alternates between the participants. In this paper, we looked at a 5-year-old’s (Lila) interaction with her mother (Mellony) and a television remote control as Lila attempted to count in threes using the three by three physical layout of the numbered buttons 1–9 on the remote control. We specifically looked at the emergence of the Zone of Proximal Development (ZPD) as Lila’s attention was caught by the properties of the remote control and by her mother’s questions. We also pay attention to how the role of the more knowledgeable other alternates among the participants. Our findings suggest that Lila, at times, used resources provided by the physical properties of the remote control and sometimes, used resources provided by Mellony to think about the task of counting in threes. In Lila’s interaction, we interpreted a multi-directional ZPD as the role of the more knowledgeable other alternated between Mellony, Lila and the remote control.
- Full Text:
- Date Issued: 2009
An update on the management of breast cancer in Africa
- Vanderpuye, V, Grover, S, Hammad, N, Prabhakar, Pooja, Simonds, H, Olopade, F, Stefan, D C
- Authors: Vanderpuye, V , Grover, S , Hammad, N , Prabhakar, Pooja , Simonds, H , Olopade, F , Stefan, D C
- Date: 2017
- Subjects: Africa Cancer--Treatment
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6048 , vital:45108 , DOI 10.1186/s13027-017-0124-y
- Description: There is limited information about the challenges of cancer management and attempts at improving outcomes in Africa. Even though South and North Africa are better resourceds to tackle the burden of breast cancer, similar poor prognostic factors are common to all countries. The five-year overall Survival rate for breast cancer patients does not exceed 60% for any low and middle-income country (LMIC) in Africa. In spite of the gains achieved over the past decade, certain characteristics remain the same such as limited availability of breast conservation therapies, inadequate access to drugs, few oncology specialists and adherence to harmful socio-cultural practices. This review on managing breast cancer in Africa is authored by African oncologists who practice or collaborate in Africa and with hands-on experience with the realities. A search was performed via electronic databases from 1999 to 2016. (PubMed/Medline, African Journals Online) for all literature in English or translated into English, covering the terms "breast cancer in Africa and developing countries". One hundred ninety were deemed appropriate. Breast tumors are diagnosed at earlier ages and later stages than in highincome countries. There is a higher prevalence of triple-negative cancers. The limitations of poor nursing care and surgery, inadequate access to radiotherapy, poor availability of basic and modern systemic therapies translate into lower survival rate. Positive strides in breast cancer management in Africa include increased adaptation of treatment guidelines, improved pathology services including immuno-histochemistry, expansion and upgrading of radiotherapy equipment across the continent in addition to more research opportunities. This review is an update of the management of breast cancer in Africa, taking a look at the epidemiology, pathology, management resources, outcomes, research and limitations in Africa from the perspective of oncologists with local experience.
- Full Text:
- Date Issued: 2017
- Authors: Vanderpuye, V , Grover, S , Hammad, N , Prabhakar, Pooja , Simonds, H , Olopade, F , Stefan, D C
- Date: 2017
- Subjects: Africa Cancer--Treatment
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6048 , vital:45108 , DOI 10.1186/s13027-017-0124-y
- Description: There is limited information about the challenges of cancer management and attempts at improving outcomes in Africa. Even though South and North Africa are better resourceds to tackle the burden of breast cancer, similar poor prognostic factors are common to all countries. The five-year overall Survival rate for breast cancer patients does not exceed 60% for any low and middle-income country (LMIC) in Africa. In spite of the gains achieved over the past decade, certain characteristics remain the same such as limited availability of breast conservation therapies, inadequate access to drugs, few oncology specialists and adherence to harmful socio-cultural practices. This review on managing breast cancer in Africa is authored by African oncologists who practice or collaborate in Africa and with hands-on experience with the realities. A search was performed via electronic databases from 1999 to 2016. (PubMed/Medline, African Journals Online) for all literature in English or translated into English, covering the terms "breast cancer in Africa and developing countries". One hundred ninety were deemed appropriate. Breast tumors are diagnosed at earlier ages and later stages than in highincome countries. There is a higher prevalence of triple-negative cancers. The limitations of poor nursing care and surgery, inadequate access to radiotherapy, poor availability of basic and modern systemic therapies translate into lower survival rate. Positive strides in breast cancer management in Africa include increased adaptation of treatment guidelines, improved pathology services including immuno-histochemistry, expansion and upgrading of radiotherapy equipment across the continent in addition to more research opportunities. This review is an update of the management of breast cancer in Africa, taking a look at the epidemiology, pathology, management resources, outcomes, research and limitations in Africa from the perspective of oncologists with local experience.
- Full Text:
- Date Issued: 2017
Beyond health care providers’recommendations: understandinginfluences on infant feeding choices ofwomen with HIV in the Eastern Cape,South Africa
- Adeniyi, Oladele Vincent, Ajayi, Anthony Idowu, Issah, Moshood, Owolabi, Eyitayo Omolara, Ter Goon, Daniel, Avramovic, Gordana, Lambert, John
- Authors: Adeniyi, Oladele Vincent , Ajayi, Anthony Idowu , Issah, Moshood , Owolabi, Eyitayo Omolara , Ter Goon, Daniel , Avramovic, Gordana , Lambert, John
- Date: 2017
- Subjects: Africa Infant Feeding Sub-sahara
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6063 , vital:45109 , https://doi.org/10.1186/s13006-019-0201-5
- Description: Background: Despite the array of studies on infant feeding practices of HIV-infected women, gaps still exist in the understanding of the underlying reasons for their infant feeding choices. Potential for behavioural change exists, especially in the light of the 2016 updated World Health Organization guideline on HIV and infant feeding. The aim of this paper is to determine the rate of adoption of exclusive breastfeeding in this cohort, examine the determinants of infant feeding choices of HIV-infected women and assess the underlying reasons for these choices. Methods: This was a mixed methods study conducted between September 2015 and May 2016. It analyses the quantitative and qualitative data of 1662 peripartum women enrolled in the East London Prospective Cohort Study across three large maternity services in the Eastern Cape. Women with HIV reported their preferred choices of infant feeding. In addition, participants explained the underlying reasons for their choices. Descriptive and inferential statistics summarised the quantitative data, while thematic content analysis was performed on qualitative data. Results: Of the 1662 women with complete responses, 80.3% opted to exclusively breastfeed their babies. In the adjusted model, up to grade 12 education level (AOR: 1.81; 95% CI: 1.14, 2.86), rural/peri-urban residence (AOR:1.44; 95% CI: 1.05, 1.96), alcohol use (AOR: 1.65; 95% CI: 1.25, 2.18), negative or unknown HIV status at booking (AOR:1.85; 95% CI:1.27, 2.70), currently married (AOR:1.43; 95% CI:1.01, 2.02) and WHO Clinical Stage 2–4 (AOR:1.77; 95% CI: 1.15, 2.72) were significantly associated with the decision to exclusively breastfeed. Health care providers’ recommendations, perceived benefits of breastfeeding, unaffordability of formula feeding, and coercion were the underlying reasons for wanting to breastfeed; while work/school-related demands, breast-related issues, and fear of infecting the baby influenced their decision to formula feed. Conclusion: The majority of HIV-infected women chose to breastfeed their babies in the Eastern Cape. Following up on these women to ensure they breastfeed exclusively, while also addressing their possible concerns, could be an important policy intervention. Future studies should focus on how early infant feeding decisions change over time, as well as the health outcomes for mother and child. Keywords: Exclusive breastfeeding, Infant feeding practice, infant formula feeding, HIV-infected peripartum women, South Africa, WHO guideline
- Full Text:
- Date Issued: 2017
- Authors: Adeniyi, Oladele Vincent , Ajayi, Anthony Idowu , Issah, Moshood , Owolabi, Eyitayo Omolara , Ter Goon, Daniel , Avramovic, Gordana , Lambert, John
- Date: 2017
- Subjects: Africa Infant Feeding Sub-sahara
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/6063 , vital:45109 , https://doi.org/10.1186/s13006-019-0201-5
- Description: Background: Despite the array of studies on infant feeding practices of HIV-infected women, gaps still exist in the understanding of the underlying reasons for their infant feeding choices. Potential for behavioural change exists, especially in the light of the 2016 updated World Health Organization guideline on HIV and infant feeding. The aim of this paper is to determine the rate of adoption of exclusive breastfeeding in this cohort, examine the determinants of infant feeding choices of HIV-infected women and assess the underlying reasons for these choices. Methods: This was a mixed methods study conducted between September 2015 and May 2016. It analyses the quantitative and qualitative data of 1662 peripartum women enrolled in the East London Prospective Cohort Study across three large maternity services in the Eastern Cape. Women with HIV reported their preferred choices of infant feeding. In addition, participants explained the underlying reasons for their choices. Descriptive and inferential statistics summarised the quantitative data, while thematic content analysis was performed on qualitative data. Results: Of the 1662 women with complete responses, 80.3% opted to exclusively breastfeed their babies. In the adjusted model, up to grade 12 education level (AOR: 1.81; 95% CI: 1.14, 2.86), rural/peri-urban residence (AOR:1.44; 95% CI: 1.05, 1.96), alcohol use (AOR: 1.65; 95% CI: 1.25, 2.18), negative or unknown HIV status at booking (AOR:1.85; 95% CI:1.27, 2.70), currently married (AOR:1.43; 95% CI:1.01, 2.02) and WHO Clinical Stage 2–4 (AOR:1.77; 95% CI: 1.15, 2.72) were significantly associated with the decision to exclusively breastfeed. Health care providers’ recommendations, perceived benefits of breastfeeding, unaffordability of formula feeding, and coercion were the underlying reasons for wanting to breastfeed; while work/school-related demands, breast-related issues, and fear of infecting the baby influenced their decision to formula feed. Conclusion: The majority of HIV-infected women chose to breastfeed their babies in the Eastern Cape. Following up on these women to ensure they breastfeed exclusively, while also addressing their possible concerns, could be an important policy intervention. Future studies should focus on how early infant feeding decisions change over time, as well as the health outcomes for mother and child. Keywords: Exclusive breastfeeding, Infant feeding practice, infant formula feeding, HIV-infected peripartum women, South Africa, WHO guideline
- Full Text:
- Date Issued: 2017
Changes in forest cover and carbon stocks of the coastal scarp forests of the Wild Coast, South Africa
- Mangwale, Kagiso, Shackleton, Charlie M, Sigwela, Ayanda
- Authors: Mangwale, Kagiso , Shackleton, Charlie M , Sigwela, Ayanda
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60903 , vital:27887 , https://doi.org/10.2989/20702620.2016.1255480
- Description: Land-use intensification and declines in vegetative cover are considered pervasive threats to forests and biodiversity globally. The small extent and high biodiversity of indigenous forests in South Africa make them particularly important. Yet, relatively little is known about their rates of use and change. From analysis of past aerial photos we quantified rates of forest cover change in the Matiwane forests of the Wild Coast, South Africa, between 1942 and 2007, as well as quantified above- and belowground (to 0.5 m depth) carbon stocks based on a composite allometric equation derived for the area. Rates of forest conversion were spatially variable, with some areas showing no change and others more noticeable changes. Overall, the net reduction was 5.2% (0.08% p.a.) over the 65-year period. However, the rate of reduction has accelerated with time. Some of the reduction was balanced by natural reforestation into formerly cleared areas, but basal area, biomass and carbon stocks are still low in the reforested areas. The total carbon stock was highest in intact forests (311.7 ± 23.7 Mg C ha−1), followed by degraded forests (73.5 ± 12.3 Mg C ha−1) and least in regrowth forests (51.2 ± 6.2 Mg C ha−1). The greatest contribution to total carbon stocks was soil carbon, contributing 54% in intact forests, and 78% and 68% in degraded and regrowth forests, respectively. The Matiwane forests store 4.78 Tg C, with 4.7 Tg C in intact forests, 0.06 Tg C in degraded forests and 0.02 Tg C in regrowth forests. The decrease in carbon stocks within the forests as a result of the conversion of the forest area to agricultural fields was 0.19 Tg C and approximately 0.0003 Tg C was released through harvesting of firewood and building timber.
- Full Text:
- Date Issued: 2017
- Authors: Mangwale, Kagiso , Shackleton, Charlie M , Sigwela, Ayanda
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60903 , vital:27887 , https://doi.org/10.2989/20702620.2016.1255480
- Description: Land-use intensification and declines in vegetative cover are considered pervasive threats to forests and biodiversity globally. The small extent and high biodiversity of indigenous forests in South Africa make them particularly important. Yet, relatively little is known about their rates of use and change. From analysis of past aerial photos we quantified rates of forest cover change in the Matiwane forests of the Wild Coast, South Africa, between 1942 and 2007, as well as quantified above- and belowground (to 0.5 m depth) carbon stocks based on a composite allometric equation derived for the area. Rates of forest conversion were spatially variable, with some areas showing no change and others more noticeable changes. Overall, the net reduction was 5.2% (0.08% p.a.) over the 65-year period. However, the rate of reduction has accelerated with time. Some of the reduction was balanced by natural reforestation into formerly cleared areas, but basal area, biomass and carbon stocks are still low in the reforested areas. The total carbon stock was highest in intact forests (311.7 ± 23.7 Mg C ha−1), followed by degraded forests (73.5 ± 12.3 Mg C ha−1) and least in regrowth forests (51.2 ± 6.2 Mg C ha−1). The greatest contribution to total carbon stocks was soil carbon, contributing 54% in intact forests, and 78% and 68% in degraded and regrowth forests, respectively. The Matiwane forests store 4.78 Tg C, with 4.7 Tg C in intact forests, 0.06 Tg C in degraded forests and 0.02 Tg C in regrowth forests. The decrease in carbon stocks within the forests as a result of the conversion of the forest area to agricultural fields was 0.19 Tg C and approximately 0.0003 Tg C was released through harvesting of firewood and building timber.
- Full Text:
- Date Issued: 2017
Developing academic literacies through understanding the nature of disciplinary knowledge
- Clarence, Sherran, McKenna, Sioux
- Authors: Clarence, Sherran , McKenna, Sioux
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61062 , vital:27942 , https://doi.org/10.18546/LRE.15.1.04
- Description: Much academic development work that is framed by academic literacies, especially that focused on writing, is concerned with disciplinary conventions and knowledges: conceptual, practical, and procedural. This paper argues, however, that academic literacies work tends to conflate literacy practices with disciplinary knowledge structures, thus obscuring the structures from which these practices emanate. This paper demonstrates how theoretical and analytical tools for conceptualizing disciplinary knowledge structures can connect these with academic literacies development work. Using recent studies that combine academic literacies and theories of knowledge in novel ways, this paper will show that understanding the knowledge structures of different disciplines can enable academic developers to build a stronger body of practice. This will enable academic developers working within disciplinary contexts to more ably speak to the nature of coming to know in higher education.
- Full Text:
- Date Issued: 2017
- Authors: Clarence, Sherran , McKenna, Sioux
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/61062 , vital:27942 , https://doi.org/10.18546/LRE.15.1.04
- Description: Much academic development work that is framed by academic literacies, especially that focused on writing, is concerned with disciplinary conventions and knowledges: conceptual, practical, and procedural. This paper argues, however, that academic literacies work tends to conflate literacy practices with disciplinary knowledge structures, thus obscuring the structures from which these practices emanate. This paper demonstrates how theoretical and analytical tools for conceptualizing disciplinary knowledge structures can connect these with academic literacies development work. Using recent studies that combine academic literacies and theories of knowledge in novel ways, this paper will show that understanding the knowledge structures of different disciplines can enable academic developers to build a stronger body of practice. This will enable academic developers working within disciplinary contexts to more ably speak to the nature of coming to know in higher education.
- Full Text:
- Date Issued: 2017
Development of an item bank of health literacy questions appropriate for limited literacy public sector patients in South Africa:
- Marimwe, Chipiwa, Dowse, Roslind
- Authors: Marimwe, Chipiwa , Dowse, Roslind
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156618 , vital:40031 , https://doi.org/10.1080/17538068.2017.1380577
- Description: The majority of current health literacy measures emanate from high-income countries. In South Africa, there is no appropriate measure available for use by the diverse public sector population, many of whom have some literacy limitations. The objective was to develop a bank of questions for this population informed by a broader definition of health literacy, which acknowledges both traditional cognitive skills and explores the influence of the collective social environment on health literacy. Thirty questions for the Item Bank were developed to ensure cultural, contextual and educational appropriateness, and were continuously subjected to critical review by an expert consultant panel. Patients (n = 120) were recruited from a local primary care clinic and individually interviewed with the assistance of an interpreter to collect data on the Item Bank, Multidimensional Screener of Functional Health Literacy (MSFHL) and sociodemographics.
- Full Text:
- Date Issued: 2017
- Authors: Marimwe, Chipiwa , Dowse, Roslind
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156618 , vital:40031 , https://doi.org/10.1080/17538068.2017.1380577
- Description: The majority of current health literacy measures emanate from high-income countries. In South Africa, there is no appropriate measure available for use by the diverse public sector population, many of whom have some literacy limitations. The objective was to develop a bank of questions for this population informed by a broader definition of health literacy, which acknowledges both traditional cognitive skills and explores the influence of the collective social environment on health literacy. Thirty questions for the Item Bank were developed to ensure cultural, contextual and educational appropriateness, and were continuously subjected to critical review by an expert consultant panel. Patients (n = 120) were recruited from a local primary care clinic and individually interviewed with the assistance of an interpreter to collect data on the Item Bank, Multidimensional Screener of Functional Health Literacy (MSFHL) and sociodemographics.
- Full Text:
- Date Issued: 2017
Examining the nature of learning within an afterschool mathematics club : a case study of four learners
- Pohamba, Penehafo K, Graven, Mellony, Stott, Deborah A, Ashipala, Daniel O
- Authors: Pohamba, Penehafo K , Graven, Mellony , Stott, Deborah A , Ashipala, Daniel O
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70121 , vital:29623 , http://dx.doi.org/10.5430/irhe.v2n1p21
- Description: This study examined the nature of learning within an afterschool mathematics club established by the South African Numeracy Chair project. This study sought to establish what sort of progress in mathematical learning occurred in a grade 3 afterschool maths club, using assessment instruments associated with the Learning Framework in Number. The study also sought to understand the nature and effects of mentor mediation in the maths club, using Vygotsky’s notion of the Zone of Proximal Development (ZPD) together with the notion and practice of scaffolding. This study was interpretive in nature drawing on qualitative methods with some elements of quantification in relation to learners’ progression. The club consists of 10 learners of mixed ability (5 girls and 5 boys) at a township school in Graham’s town, South Africa. Learners in this case study were selected through purposive sampling. As part of the data collection strategies, the learners were interviewed twice in terms of their numeracy proficiency. The assessment interview results revealed that, in terms of proficiency in early arithmetical learning, all four learners showed progress after spending four months in an afterschool maths club. This study also recommended Wright et al.’s (2006) LFIN framework to be used in assessing learners’ progress in mathematics, as it could inform the refinement of instructional design within the school curriculum and teachers’ education in the Namibian context.
- Full Text:
- Date Issued: 2017
- Authors: Pohamba, Penehafo K , Graven, Mellony , Stott, Deborah A , Ashipala, Daniel O
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70121 , vital:29623 , http://dx.doi.org/10.5430/irhe.v2n1p21
- Description: This study examined the nature of learning within an afterschool mathematics club established by the South African Numeracy Chair project. This study sought to establish what sort of progress in mathematical learning occurred in a grade 3 afterschool maths club, using assessment instruments associated with the Learning Framework in Number. The study also sought to understand the nature and effects of mentor mediation in the maths club, using Vygotsky’s notion of the Zone of Proximal Development (ZPD) together with the notion and practice of scaffolding. This study was interpretive in nature drawing on qualitative methods with some elements of quantification in relation to learners’ progression. The club consists of 10 learners of mixed ability (5 girls and 5 boys) at a township school in Graham’s town, South Africa. Learners in this case study were selected through purposive sampling. As part of the data collection strategies, the learners were interviewed twice in terms of their numeracy proficiency. The assessment interview results revealed that, in terms of proficiency in early arithmetical learning, all four learners showed progress after spending four months in an afterschool maths club. This study also recommended Wright et al.’s (2006) LFIN framework to be used in assessing learners’ progress in mathematics, as it could inform the refinement of instructional design within the school curriculum and teachers’ education in the Namibian context.
- Full Text:
- Date Issued: 2017
From Technauriture to Cultauriture: Developing a Coherent Digitisation Paradigm for Enhancing Cultural Impact
- Mostert, Andre, Lisney, Bob, Maroko, Geoffrey M, Kaschula, Russell H
- Authors: Mostert, Andre , Lisney, Bob , Maroko, Geoffrey M , Kaschula, Russell H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124528 , vital:35625 , http://www.ijscl.net/article_26650.html
- Description: Developing suitable frameworks and paradigms (theoretical and practical) is a challenge for all disciplines in the face of rapid technological changes. Technological advances are fundamentally changing discourse in many well-established areas of research; from advances in understanding the brain, questioning the informed wisdom of sectors of the brain, through to impacts of social networks on sociology, to digitisation of culture. Technology’s potential is a double-edged sword which calls for coherent and reflective practices, to avoid the many pitfalls which abound. Kaschula recognised this as far back as 2004 in terms of orality, oral societies, and developed Technauriture as a framing solution. Drawing from this experience, the authors aim to expand the concept to offer a framing paradigm for culture in the form of Cultauriture. In this article the concept of Cultauriture is introduced and expanded to create a base for further research and dialogue with and between cultural practitioners, artists and policy makers.
- Full Text:
- Date Issued: 2017
- Authors: Mostert, Andre , Lisney, Bob , Maroko, Geoffrey M , Kaschula, Russell H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124528 , vital:35625 , http://www.ijscl.net/article_26650.html
- Description: Developing suitable frameworks and paradigms (theoretical and practical) is a challenge for all disciplines in the face of rapid technological changes. Technological advances are fundamentally changing discourse in many well-established areas of research; from advances in understanding the brain, questioning the informed wisdom of sectors of the brain, through to impacts of social networks on sociology, to digitisation of culture. Technology’s potential is a double-edged sword which calls for coherent and reflective practices, to avoid the many pitfalls which abound. Kaschula recognised this as far back as 2004 in terms of orality, oral societies, and developed Technauriture as a framing solution. Drawing from this experience, the authors aim to expand the concept to offer a framing paradigm for culture in the form of Cultauriture. In this article the concept of Cultauriture is introduced and expanded to create a base for further research and dialogue with and between cultural practitioners, artists and policy makers.
- Full Text:
- Date Issued: 2017
Nocturnal oviposition behavior of blowflies (Diptera: Calliphoridae) in the southern hemisphere (South Africa and Australia) and its forensic implications:
- Williams, Kirstin A, Wallman, James F, Lessard, Bryan D, Kavazos, Christopher R J, Mazungula, D Nkosinathi, Villet, Martin H
- Authors: Williams, Kirstin A , Wallman, James F , Lessard, Bryan D , Kavazos, Christopher R J , Mazungula, D Nkosinathi , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140832 , vital:37922 , DOI: 10.1007/s12024-017-9861-x
- Description: Published research has offered contradictory evidence of the occurrence of nocturnal oviposition by carrion-breeding blowflies, a behavior that can affect the interpretation of forensic estimates of a minimum post mortem interval (minPMI) by up to 12 hours, depending on latitude and season. The majority of published studies are from the northern hemisphere. Field experiments were conducted in South Africa and Australia that extend observations to species of the southern hemisphere. Various vertebrate carrion was exposed at night in summer under different lunar phases and/or artificial lighting, and in woodland and pasture areas. Three laboratory experiments were also conducted. No nocturnal oviposition occurred outdoors in Berry, Australia, but Lucilia cuprina, Lucilia sericata and Chrysomya megacephala laid eggs outdoors at night in Grahamstown and Durban, South Africa. In laboratory experiments L. sericata, L. cuprina, Chrysomya chloropyga and Chrysomya putoria laid eggs and Calliphora augur deposited larvae under nocturnal conditions.
- Full Text:
- Date Issued: 2017
- Authors: Williams, Kirstin A , Wallman, James F , Lessard, Bryan D , Kavazos, Christopher R J , Mazungula, D Nkosinathi , Villet, Martin H
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140832 , vital:37922 , DOI: 10.1007/s12024-017-9861-x
- Description: Published research has offered contradictory evidence of the occurrence of nocturnal oviposition by carrion-breeding blowflies, a behavior that can affect the interpretation of forensic estimates of a minimum post mortem interval (minPMI) by up to 12 hours, depending on latitude and season. The majority of published studies are from the northern hemisphere. Field experiments were conducted in South Africa and Australia that extend observations to species of the southern hemisphere. Various vertebrate carrion was exposed at night in summer under different lunar phases and/or artificial lighting, and in woodland and pasture areas. Three laboratory experiments were also conducted. No nocturnal oviposition occurred outdoors in Berry, Australia, but Lucilia cuprina, Lucilia sericata and Chrysomya megacephala laid eggs outdoors at night in Grahamstown and Durban, South Africa. In laboratory experiments L. sericata, L. cuprina, Chrysomya chloropyga and Chrysomya putoria laid eggs and Calliphora augur deposited larvae under nocturnal conditions.
- Full Text:
- Date Issued: 2017
Omics-based molecular techniques in oral pathology centred cancer: prospect and challenges in Africa
- Adeola, Henry A., Soyele, Olujide.O., Adefuye, Anthonio O., Jimoh, Sikiru A., Butali, Azeez
- Authors: Adeola, Henry A. , Soyele, Olujide.O. , Adefuye, Anthonio O. , Jimoh, Sikiru A. , Butali, Azeez
- Date: 2017
- Subjects: Eastern Cape, South Africa Oral mucosa--Cancer Oral Pathology Cancer Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5857 , vital:44658 , https://DOI10.1186/s12935-017-0432-8
- Description: Background:The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and “big data” processing have contributed immensely to individualized/personalized medicine in the developed world.Main body:At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratification of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the proficiency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among different human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences.Conclusion:In this review, we examined the challenges and prospects of using currently available omics-based technologies vis-à-vis oral pathology as well as prompt cancer diagnosis and treatment in a resource limited setting.Keywords:Omics-based, Molecular, Developing world, Oral pathology, Challenges
- Full Text:
- Date Issued: 2017
Omics-based molecular techniques in oral pathology centred cancer: prospect and challenges in Africa
- Authors: Adeola, Henry A. , Soyele, Olujide.O. , Adefuye, Anthonio O. , Jimoh, Sikiru A. , Butali, Azeez
- Date: 2017
- Subjects: Eastern Cape, South Africa Oral mucosa--Cancer Oral Pathology Cancer Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5857 , vital:44658 , https://DOI10.1186/s12935-017-0432-8
- Description: Background:The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and “big data” processing have contributed immensely to individualized/personalized medicine in the developed world.Main body:At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratification of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the proficiency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among different human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences.Conclusion:In this review, we examined the challenges and prospects of using currently available omics-based technologies vis-à-vis oral pathology as well as prompt cancer diagnosis and treatment in a resource limited setting.Keywords:Omics-based, Molecular, Developing world, Oral pathology, Challenges
- Full Text:
- Date Issued: 2017
Reimag [in] ing the village as a portrait of a nation-state in Uganda:
- Authors: Kakande, Angelo
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145642 , vital:38454 , https://doi.org/10.1162/AFAR_a_00343
- Description: In this article I reexamine the ways in which certain contemporary artists based in Uganda problematize the narrative that the ruling National Resistance Movement (the NRM) party is the party of the rural poor (Cheeseman, Lynch, and Willis 2016) in their work while using it as a metaphor to inform their visual expression. I focus on the contest between tradition (imagined as a village) and modernity (imagined as a modern state), as well as the dilemma such a contest causes for a contemporary artist. Cornelius Adepegba (1995) argues that this dilemma influenced the African novel. Agreeing with Adepegba, Freeborn Odiboh (2009) observes that the same dilemma has shaped African visual artists, such as Abayomi Barber, and formal art education institutions like the Barber School in Nigeria; Odiboh then assesses the historical context in which this dilemma evolved as African nationalists struggled to forge postcolonial states based on a national consciousness amid competing ethnic, religious, and ideological interests.
- Full Text:
- Date Issued: 2017
- Authors: Kakande, Angelo
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145642 , vital:38454 , https://doi.org/10.1162/AFAR_a_00343
- Description: In this article I reexamine the ways in which certain contemporary artists based in Uganda problematize the narrative that the ruling National Resistance Movement (the NRM) party is the party of the rural poor (Cheeseman, Lynch, and Willis 2016) in their work while using it as a metaphor to inform their visual expression. I focus on the contest between tradition (imagined as a village) and modernity (imagined as a modern state), as well as the dilemma such a contest causes for a contemporary artist. Cornelius Adepegba (1995) argues that this dilemma influenced the African novel. Agreeing with Adepegba, Freeborn Odiboh (2009) observes that the same dilemma has shaped African visual artists, such as Abayomi Barber, and formal art education institutions like the Barber School in Nigeria; Odiboh then assesses the historical context in which this dilemma evolved as African nationalists struggled to forge postcolonial states based on a national consciousness amid competing ethnic, religious, and ideological interests.
- Full Text:
- Date Issued: 2017
Resisting the desire for the unambiguous: productive gaps in researcher, teacher and student interpretations of a number story task
- Authors: Graven, Mellony , Coles, Alf
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69673 , vital:29564 , https://DOI: 10.1007/s11858-017-0863-7
- Description: This article offers reflections on task design in the context of a Grade R (reception year) in-service numeracy project in South Africa. The research explores under what conditions, and for what learning purpose, a task designed by someone else may be recast and how varying given task specifications may support or inhibit learning, as a result of that recasting. This question is situated within a two-pronged task design challenge as to emerging gaps between the task designer’s intentions and teacher’s actions and secondly between the teachers’ intentions and students’ actions. Through analysing two teachers and their respective Grade R students’ interpretations of a worksheet task, provided to teachers in the project, we illuminate the way explicit constraints, in the form of task specifications, can be both enabling and constraining of learning. In so doing we recast this ‘double gap’ as enabling productive learning spaces for teacher educators, teachers and students.
- Full Text:
- Date Issued: 2017
- Authors: Graven, Mellony , Coles, Alf
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69673 , vital:29564 , https://DOI: 10.1007/s11858-017-0863-7
- Description: This article offers reflections on task design in the context of a Grade R (reception year) in-service numeracy project in South Africa. The research explores under what conditions, and for what learning purpose, a task designed by someone else may be recast and how varying given task specifications may support or inhibit learning, as a result of that recasting. This question is situated within a two-pronged task design challenge as to emerging gaps between the task designer’s intentions and teacher’s actions and secondly between the teachers’ intentions and students’ actions. Through analysing two teachers and their respective Grade R students’ interpretations of a worksheet task, provided to teachers in the project, we illuminate the way explicit constraints, in the form of task specifications, can be both enabling and constraining of learning. In so doing we recast this ‘double gap’ as enabling productive learning spaces for teacher educators, teachers and students.
- Full Text:
- Date Issued: 2017
Species identification of adult African blowflies (Diptera: Calliphoridae) of forensic importance:
- Lutz, Lena, Williams, Kristin A, Villet, Martin H, Ekanem, Mfon
- Authors: Lutz, Lena , Williams, Kristin A , Villet, Martin H , Ekanem, Mfon
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140620 , vital:37904 , DOI: 10.1007/s00414-017-1654-y
- Description: Necrophagous blowflies can provide an excellent source of evidence for forensic entomologists and are also relevant to problems in public health, medicine, and animal health. However, access to useful information about these blowflies is constrained by the need to correctly identify the flies, and the poor availability of reliable, accessible identification tools is a serious obstacle to the development of forensic entomology in the majority of African countries. In response to this need, a high-quality key to the adults of all species of forensically relevant blowflies of Africa has been prepared, drawing on high-quality entomological materials and modern focus-stacking photomicroscopy. This new key can be easily applied by investigators inexperienced in the taxonomy of blowflies and is made available through a highly accessible online platform. Problematic diagnostic characters used in previous keys are discussed.
- Full Text:
- Date Issued: 2017
- Authors: Lutz, Lena , Williams, Kristin A , Villet, Martin H , Ekanem, Mfon
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/140620 , vital:37904 , DOI: 10.1007/s00414-017-1654-y
- Description: Necrophagous blowflies can provide an excellent source of evidence for forensic entomologists and are also relevant to problems in public health, medicine, and animal health. However, access to useful information about these blowflies is constrained by the need to correctly identify the flies, and the poor availability of reliable, accessible identification tools is a serious obstacle to the development of forensic entomology in the majority of African countries. In response to this need, a high-quality key to the adults of all species of forensically relevant blowflies of Africa has been prepared, drawing on high-quality entomological materials and modern focus-stacking photomicroscopy. This new key can be easily applied by investigators inexperienced in the taxonomy of blowflies and is made available through a highly accessible online platform. Problematic diagnostic characters used in previous keys are discussed.
- Full Text:
- Date Issued: 2017
Structure-based analysis of single nucleotide variants in the renin-angiotensinogen complex:
- Brown, David K, Olivier, Sheik Amamuddy, Tastan Bishop, Özlem
- Authors: Brown, David K , Olivier, Sheik Amamuddy , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147994 , vital:38700 , https://doi.org/10.1016/j.gheart.2017.01.006
- Description: The renin-angiotensin system (RAS) plays an important role in regulating blood pressure and controlling sodium levels in the blood. Hyperactivity of this system has been linked to numerous conditions including hypertension, kidney disease, and congestive heart failure. Three classes of drugs have been developed to inhibit RAS. In this study, we provide a structure-based analysis of the effect of single nucleotide variants (SNVs) on the interaction between renin and angiotensinogen with the aim of revealing important residues and potentially damaging variants for further inhibitor design purposes.
- Full Text:
- Date Issued: 2017
- Authors: Brown, David K , Olivier, Sheik Amamuddy , Tastan Bishop, Özlem
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147994 , vital:38700 , https://doi.org/10.1016/j.gheart.2017.01.006
- Description: The renin-angiotensin system (RAS) plays an important role in regulating blood pressure and controlling sodium levels in the blood. Hyperactivity of this system has been linked to numerous conditions including hypertension, kidney disease, and congestive heart failure. Three classes of drugs have been developed to inhibit RAS. In this study, we provide a structure-based analysis of the effect of single nucleotide variants (SNVs) on the interaction between renin and angiotensinogen with the aim of revealing important residues and potentially damaging variants for further inhibitor design purposes.
- Full Text:
- Date Issued: 2017
The biological control of aquatic weeds in South Africa: current status and future challenges
- Hill, Martin P, Coetzee, Julie A
- Authors: Hill, Martin P , Coetzee, Julie A
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59909 , vital:27706 , https://doi.org/10.4102/abc.v47i2.2152
- Description: Aquatic ecosystems in South Africa have been prone to invasion by introduced macrophytes since the late 1800s, when water hyacinth, Eichhornia crassipes (Mart.) Solms-Laub. (Pontederiaceae), was first recorded as naturalised in KwaZulu-Natal (Cilliers 1991). Several other species of freshwater aquatic plants, all notorious weeds in other parts of the world, have also become invasive in many of the rivers, man-made impoundments, lakes and wetlands of South Africa (Hill 2003). These are Pistia stratiotes L. (Araceae) (water lettuce); Salvinia molesta D.S. Mitch. (Salviniaceae) (salvinia); Myriophyllum aquaticum (Vell. Conc.) Verd. (parrot's feather); and Azolla filiculoides Lam. (Azollaceae) (red water fern) (Hill 2003), which along with water hyacinth comprise the 'Big Bad Five' (Henderson & Cilliers 2002). Recently, new invasive aquatic plant species have been recorded which are still at their early stages of invasion, including the submerged species, Egeria densa Planch. (Hydrocharitaceae) (Brazilian water weed) and Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae); the emergent species, Sagittaria platyphylla (Engelm.) J.G.Sm. and S. latifolia Willd. (Alismataceae); Lythrum salicaria L. (Lythraceae) (purple loosestrife), Nasturtium officinale W.T. Aiton. (Brassicaceae) (watercress); Iris pseudacorus L. (Iridaceae) (yellow flag); and Hydrocleys nymphoides (Humb. & Bonpl. ex Willd.) Buchenau (Alismataceae) (water poppy); and the new floating weeds, Salvinia minima Baker (Salviniaceae) and Azolla cristata Kaulf. (Azollaceae) (Mexican azolla); and the rooted floating Nymphaea mexicana Zucc. (Nymphaeceae) (Mexican water lily) (Coetzee et al. 2011a; Coetzee, Bownes & Martin 2011b). The mode of introduction of these species is mainly through the horticultural and aquarium trade (Martin & Coetzee 2011), and two issues contribute to the invasiveness of these macrophytes following establishment: the lack of co-evolved natural enemies in their adventive range (McFadyen 1998); and disturbance, the presence of nitrate- and phosphate-enriched waters, associated with urban, agricultural and industrial pollution that promotes plant growth (Coetzee & Hill 2012).
- Full Text:
- Date Issued: 2017
- Authors: Hill, Martin P , Coetzee, Julie A
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59909 , vital:27706 , https://doi.org/10.4102/abc.v47i2.2152
- Description: Aquatic ecosystems in South Africa have been prone to invasion by introduced macrophytes since the late 1800s, when water hyacinth, Eichhornia crassipes (Mart.) Solms-Laub. (Pontederiaceae), was first recorded as naturalised in KwaZulu-Natal (Cilliers 1991). Several other species of freshwater aquatic plants, all notorious weeds in other parts of the world, have also become invasive in many of the rivers, man-made impoundments, lakes and wetlands of South Africa (Hill 2003). These are Pistia stratiotes L. (Araceae) (water lettuce); Salvinia molesta D.S. Mitch. (Salviniaceae) (salvinia); Myriophyllum aquaticum (Vell. Conc.) Verd. (parrot's feather); and Azolla filiculoides Lam. (Azollaceae) (red water fern) (Hill 2003), which along with water hyacinth comprise the 'Big Bad Five' (Henderson & Cilliers 2002). Recently, new invasive aquatic plant species have been recorded which are still at their early stages of invasion, including the submerged species, Egeria densa Planch. (Hydrocharitaceae) (Brazilian water weed) and Hydrilla verticillata (L.f.) Royle (Hydrocharitaceae); the emergent species, Sagittaria platyphylla (Engelm.) J.G.Sm. and S. latifolia Willd. (Alismataceae); Lythrum salicaria L. (Lythraceae) (purple loosestrife), Nasturtium officinale W.T. Aiton. (Brassicaceae) (watercress); Iris pseudacorus L. (Iridaceae) (yellow flag); and Hydrocleys nymphoides (Humb. & Bonpl. ex Willd.) Buchenau (Alismataceae) (water poppy); and the new floating weeds, Salvinia minima Baker (Salviniaceae) and Azolla cristata Kaulf. (Azollaceae) (Mexican azolla); and the rooted floating Nymphaea mexicana Zucc. (Nymphaeceae) (Mexican water lily) (Coetzee et al. 2011a; Coetzee, Bownes & Martin 2011b). The mode of introduction of these species is mainly through the horticultural and aquarium trade (Martin & Coetzee 2011), and two issues contribute to the invasiveness of these macrophytes following establishment: the lack of co-evolved natural enemies in their adventive range (McFadyen 1998); and disturbance, the presence of nitrate- and phosphate-enriched waters, associated with urban, agricultural and industrial pollution that promotes plant growth (Coetzee & Hill 2012).
- Full Text:
- Date Issued: 2017
“War of the worldly codes”: articulating the gap between legal academia and practice
- Authors: Clarence, Sherran
- Date: 2017
- Language: English
- Type: text , conference publication
- Identifier: http://hdl.handle.net/10962/66972 , vital:29007
- Full Text:
- Date Issued: 2017
- Authors: Clarence, Sherran
- Date: 2017
- Language: English
- Type: text , conference publication
- Identifier: http://hdl.handle.net/10962/66972 , vital:29007
- Full Text:
- Date Issued: 2017
HUMA: A platform for the analysis of genetic variation in humans
- Brown, David K, Tastan Bishop, Özlem
- Authors: Brown, David K , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124653 , vital:35642 , https://doi.10.1002/humu.23334
- Description: The completion of the human genome project at the beginning of the 21st century, along with the rapid advancement of sequencing technologies thereafter, has resulted in exponential growth of biological data. In genetics, this has given rise to numerous variation databases, created to store and annotate the ever-expanding dataset of known mutations. Usually, these databases focus on variation at the sequence level. Few databases focus on the analysis of variation at the 3D level, that is, mapping, visualizing, and determining the effects of variation in protein structures. Additionally, these Web servers seldom incorporate tools to help analyze these data. Here, we present the Human Mutation Analysis (HUMA) Web server and database. HUMA integrates sequence, structure, variation, and disease data into a single, connected database. A user-friendly interface provides click-based data access and visualization, whereas a RESTfulWebAPI provides programmatic access to the data. Tools have been integrated into HUMA to allow initial analyses to be carried out on the server. Furthermore, users can upload their private variation datasets, which are automatically mapped to public data and can be analyzed using the integrated tools. HUMA is freely accessible at https://huma.rubi.ru.ac.za.
- Full Text:
- Date Issued: 2018
- Authors: Brown, David K , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124653 , vital:35642 , https://doi.10.1002/humu.23334
- Description: The completion of the human genome project at the beginning of the 21st century, along with the rapid advancement of sequencing technologies thereafter, has resulted in exponential growth of biological data. In genetics, this has given rise to numerous variation databases, created to store and annotate the ever-expanding dataset of known mutations. Usually, these databases focus on variation at the sequence level. Few databases focus on the analysis of variation at the 3D level, that is, mapping, visualizing, and determining the effects of variation in protein structures. Additionally, these Web servers seldom incorporate tools to help analyze these data. Here, we present the Human Mutation Analysis (HUMA) Web server and database. HUMA integrates sequence, structure, variation, and disease data into a single, connected database. A user-friendly interface provides click-based data access and visualization, whereas a RESTfulWebAPI provides programmatic access to the data. Tools have been integrated into HUMA to allow initial analyses to be carried out on the server. Furthermore, users can upload their private variation datasets, which are automatically mapped to public data and can be analyzed using the integrated tools. HUMA is freely accessible at https://huma.rubi.ru.ac.za.
- Full Text:
- Date Issued: 2018
Plant–herbivore–parasitoid interactions in an experimental freshwater tritrophic system: higher trophic levels modify competitive interactions between invasive macrophytes
- Martin, Grant D, Coetzee, Julie A, Compton, Stephen
- Authors: Martin, Grant D , Coetzee, Julie A , Compton, Stephen
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125686 , vital:35808 , https://doi.org/10.1007/s10750-017-341
- Description: Natural enemies are known to modify competitive hierarchies among terrestrial plants. Here we examine whether the same applies to freshwatersystems. Lagarosiphon major (Hydrocharitaceae) is a submerged aquatic macrophyte, indigenous to South Africa. Outside its native range, it outcompetes with indigenous submerged species and degrades aquatic habitats. Hydrellia lagarosiphon (Diptera: Ephydridae) is the most abundant and ubiquitous herbivore associated with L. major in South Africa and is a potential biological control agent elsewhere. Chaenusa anervata (Hymenoptera: Braconidae: Alysiinae) is its main parasitoid. We generated an experimental system involving one, two or three trophic levels to monitor variation in the competitive ability of L. major relative to that of Myriophyllum spicatum (Haloragaceae), a second submerged macrophyte that can also be invasive. Using inverse linear models to monitor competition, we found that herbivory by H. lagarosiphon greatly reduced the competitive ability of L. major. Addition of the wasp at typical field densities halved the impact of herbivory and reestablished the competitive advantage of L. major. Our results demonstrate how multitrophic interactions modify relative competitive abilities among aquatic plants, emphasize the significance of higher tropic levels in these systems and illustrate how parasitoids can reduce the effectiveness of insects released as biocontrol agents.
- Full Text:
- Date Issued: 2018
- Authors: Martin, Grant D , Coetzee, Julie A , Compton, Stephen
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125686 , vital:35808 , https://doi.org/10.1007/s10750-017-341
- Description: Natural enemies are known to modify competitive hierarchies among terrestrial plants. Here we examine whether the same applies to freshwatersystems. Lagarosiphon major (Hydrocharitaceae) is a submerged aquatic macrophyte, indigenous to South Africa. Outside its native range, it outcompetes with indigenous submerged species and degrades aquatic habitats. Hydrellia lagarosiphon (Diptera: Ephydridae) is the most abundant and ubiquitous herbivore associated with L. major in South Africa and is a potential biological control agent elsewhere. Chaenusa anervata (Hymenoptera: Braconidae: Alysiinae) is its main parasitoid. We generated an experimental system involving one, two or three trophic levels to monitor variation in the competitive ability of L. major relative to that of Myriophyllum spicatum (Haloragaceae), a second submerged macrophyte that can also be invasive. Using inverse linear models to monitor competition, we found that herbivory by H. lagarosiphon greatly reduced the competitive ability of L. major. Addition of the wasp at typical field densities halved the impact of herbivory and reestablished the competitive advantage of L. major. Our results demonstrate how multitrophic interactions modify relative competitive abilities among aquatic plants, emphasize the significance of higher tropic levels in these systems and illustrate how parasitoids can reduce the effectiveness of insects released as biocontrol agents.
- Full Text:
- Date Issued: 2018
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