(Ferrocenylpyrazolyl) zinc (II) benzoates as catalysts for the ring opening polymerization of ε-caprolactone
- Obuah, Collins, Lochee, Yemanlall, Jordaan, Johan H L, Otto, Daniel P, Nyokong, Tebello, Darkwa, James
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
A colorimetric probe for dopamine based on gold nanoparticles-electrospun nanofibre composite
- Ngomane, Nokuthula, Torto, Nelson, Krause, Rui W M, Vilakazi, Sibulelo
- Authors: Ngomane, Nokuthula , Torto, Nelson , Krause, Rui W M , Vilakazi, Sibulelo
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195407 , vital:45562 , xlink:href="https://doi.org/10.1016/j.matpr.2015.08.036"
- Description: An easily prepared solid state colorimetric probe for detecting the neurotransmitter dopamine (DA) was developed. The probe, in the form of an electrospun Nylon−6 (N6) nanofibre with embedded un−functionalized gold nanoparticles (UF−AuNPs) produces a clear colour change in the presence of a DA that is detectable by the naked eye. Characterisation of the nanofibre using UV/vis spectroscopy and electron microscopy (TEM) confirmed the formation of the AuNPs in the polymer solution, and that the AuNPs were completely encapsulated within the composite nanofibres before exposure to the analytes. The probe exhibited very high sensitivity towards DA resulting in colour change of the composite fibres from purple to navy blue/black even under low concentrations of DA. The probe was also selective to DA since the colour remained unchanged in the presence of commonly encountered interfering species such as ascorbic acid, uric acid, catechol, epinephrine and norepinephrine. Moreover, the colour change was observed rapid, occurring either immediately on contact with higher concentrations (5 x10−4 M) or within about 3−5 min for the lower concentrations (e.g. 5 x10−7 M). Since this probe does not require the use of any instruments, and is both rapid and stable over time, it can be applied in the field by an inexperienced person.
- Full Text:
- Date Issued: 2015
- Authors: Ngomane, Nokuthula , Torto, Nelson , Krause, Rui W M , Vilakazi, Sibulelo
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/195407 , vital:45562 , xlink:href="https://doi.org/10.1016/j.matpr.2015.08.036"
- Description: An easily prepared solid state colorimetric probe for detecting the neurotransmitter dopamine (DA) was developed. The probe, in the form of an electrospun Nylon−6 (N6) nanofibre with embedded un−functionalized gold nanoparticles (UF−AuNPs) produces a clear colour change in the presence of a DA that is detectable by the naked eye. Characterisation of the nanofibre using UV/vis spectroscopy and electron microscopy (TEM) confirmed the formation of the AuNPs in the polymer solution, and that the AuNPs were completely encapsulated within the composite nanofibres before exposure to the analytes. The probe exhibited very high sensitivity towards DA resulting in colour change of the composite fibres from purple to navy blue/black even under low concentrations of DA. The probe was also selective to DA since the colour remained unchanged in the presence of commonly encountered interfering species such as ascorbic acid, uric acid, catechol, epinephrine and norepinephrine. Moreover, the colour change was observed rapid, occurring either immediately on contact with higher concentrations (5 x10−4 M) or within about 3−5 min for the lower concentrations (e.g. 5 x10−7 M). Since this probe does not require the use of any instruments, and is both rapid and stable over time, it can be applied in the field by an inexperienced person.
- Full Text:
- Date Issued: 2015
A comparative photophysicochemical study of phthalocyanines encapsulated in core–shell silica nanoparticles
- Fashina, Adedayo, Amuhaya, Edith K, Nyokong, Tebello
- Authors: Fashina, Adedayo , Amuhaya, Edith K , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189708 , vital:44924 , xlink:href="https://doi.org/10.1016/j.saa.2014.08.062"
- Description: This work presents the synthesis and characterization of a new zinc phthalocyanine complex tetrasubstituted with 3-carboxyphenoxy in the peripheral position. The photophysical properties of the new complex are compared with those of phthalocyanines tetra substituted with 3-carboxyphenoxy or 4- carboxyphenoxy at non-peripheral positions. Three phthalocyanine complexes were encapsulated within silica matrix to form a core shell and the hybrid nanoparticles particles obtained were spherical and mono dispersed. When encapsulated within the silica shell nanoparticles, phthalocyanines showed improved triplet quantum yields and singlet oxygen quantum yields than surface grafted derivatives. The improvements observed could be attributed to the protection provided for the phthalocyanine complexes by the silica matrix.
- Full Text:
- Date Issued: 2015
- Authors: Fashina, Adedayo , Amuhaya, Edith K , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189708 , vital:44924 , xlink:href="https://doi.org/10.1016/j.saa.2014.08.062"
- Description: This work presents the synthesis and characterization of a new zinc phthalocyanine complex tetrasubstituted with 3-carboxyphenoxy in the peripheral position. The photophysical properties of the new complex are compared with those of phthalocyanines tetra substituted with 3-carboxyphenoxy or 4- carboxyphenoxy at non-peripheral positions. Three phthalocyanine complexes were encapsulated within silica matrix to form a core shell and the hybrid nanoparticles particles obtained were spherical and mono dispersed. When encapsulated within the silica shell nanoparticles, phthalocyanines showed improved triplet quantum yields and singlet oxygen quantum yields than surface grafted derivatives. The improvements observed could be attributed to the protection provided for the phthalocyanine complexes by the silica matrix.
- Full Text:
- Date Issued: 2015
A Comparison of Four End-User Devices as Thin Clients for Public Access to the Internet in Poor Communities
- Duff, Kevin, Siebörger, Ingrid, Terzoli, Alfredo
- Authors: Duff, Kevin , Siebörger, Ingrid , Terzoli, Alfredo
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430892 , vital:72725 , https://doi.org/10.1007/978-3-319-16886-9_24
- Description: In poor areas, where ICT infrastructure is being deployed with devel-opmental aims, there is a need to provide appropriate, sustainable technologies that meet the needs of the local community. Current trends for ICT interventions favour the use of mobile user equipment, such as tablets and cellphones, but we think that they are inappropriate to allow production as opposed to mainly consumption of digital con-tent, at least for the foreseeable future. Thus our objective is to reduce the cost of deployment of traditional communal Internet Access Points using PCs. In this paper we compare four candidate computers to be used as thin clients in such settings, according to seven different cate-gories. Our study identifies the strengths, weaknesses and problems of each device, and concludes with recommendations for anybody wish-ing to deploy such devices as Linux Terminal Server Project (LTSP) thin clients in a public Internet Access Point.
- Full Text:
- Date Issued: 2015
- Authors: Duff, Kevin , Siebörger, Ingrid , Terzoli, Alfredo
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430892 , vital:72725 , https://doi.org/10.1007/978-3-319-16886-9_24
- Description: In poor areas, where ICT infrastructure is being deployed with devel-opmental aims, there is a need to provide appropriate, sustainable technologies that meet the needs of the local community. Current trends for ICT interventions favour the use of mobile user equipment, such as tablets and cellphones, but we think that they are inappropriate to allow production as opposed to mainly consumption of digital con-tent, at least for the foreseeable future. Thus our objective is to reduce the cost of deployment of traditional communal Internet Access Points using PCs. In this paper we compare four candidate computers to be used as thin clients in such settings, according to seven different cate-gories. Our study identifies the strengths, weaknesses and problems of each device, and concludes with recommendations for anybody wish-ing to deploy such devices as Linux Terminal Server Project (LTSP) thin clients in a public Internet Access Point.
- Full Text:
- Date Issued: 2015
A comparison of genetic structure in two low-dispersal crabs from the Wild Coast, South Africa
- Qhaji, Y, Jansen van Vuuren, Bettine, Papadopoulos, Isabelle, McQuaid, Christopher D, Teske, Peter R
- Authors: Qhaji, Y , Jansen van Vuuren, Bettine , Papadopoulos, Isabelle , McQuaid, Christopher D , Teske, Peter R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444770 , vital:74297 , https://doi.org/10.2989/1814232X.2015.1077474
- Description: The Wild Coast in south-eastern South Africa is strongly influenced by the warm, southward-flowing Agulhas Current. This current has a significant impact on dispersal in the coastal biota of the region, and facilitates high levels of connectivity among populations. However, it is not known how the region's high-velocity hydrology affects genetic population structure in endemic estuarine species, populations of which are frequently isolated from the sea. Here, we compared genetic structure in two estuarine crabs of the family Hymenosomatidae. Both are presumed to have low dispersal potential, but they differ in terms of their life histories. Hymenosoma longicrure has abbreviated larval development and can complete its entire life cycle within estuaries, whereas Neorhynchoplax bovis is a direct developer that lacks planktonic larvae.
- Full Text:
- Date Issued: 2015
- Authors: Qhaji, Y , Jansen van Vuuren, Bettine , Papadopoulos, Isabelle , McQuaid, Christopher D , Teske, Peter R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444770 , vital:74297 , https://doi.org/10.2989/1814232X.2015.1077474
- Description: The Wild Coast in south-eastern South Africa is strongly influenced by the warm, southward-flowing Agulhas Current. This current has a significant impact on dispersal in the coastal biota of the region, and facilitates high levels of connectivity among populations. However, it is not known how the region's high-velocity hydrology affects genetic population structure in endemic estuarine species, populations of which are frequently isolated from the sea. Here, we compared genetic structure in two estuarine crabs of the family Hymenosomatidae. Both are presumed to have low dispersal potential, but they differ in terms of their life histories. Hymenosoma longicrure has abbreviated larval development and can complete its entire life cycle within estuaries, whereas Neorhynchoplax bovis is a direct developer that lacks planktonic larvae.
- Full Text:
- Date Issued: 2015
A review of three generations of critical theory: Towards conceptualising critical HESD research
- Authors: Lotz-Sisitka, Heila
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437136 , vital:73345 , ISBN 9781315852249 , https://www.taylorfrancis.com/chapters/edit/10.4324/9781315852249-17/review-three-generations-critical-theory-heila-lotz-sisitka
- Description: To begin a review of the purpose(s) of ESD research, we must first ask the basic question of the purpose of research generally. Definitions of research normally centre on it comprising sys-tematic investigation which contributes to knowledge or under-standing of phenomena or a problem. A distinction is common-ly drawn between pure or basic research which focuses on understanding phenomena and issues, and applied research where the primary emphasis is on research which contributes to the solution of problems or some systemic improvement ra-ther than knowledge for its own sake. Some commentators see action research as a third category as it is predicated on the researcher being part of the research process which itself is committed to personal or social change. ESD research as an area of interest is perhaps unusual because it accommodates and crosses these categories. It also engages in philosophic research regarding cultural, worldview and ethical dimensions of sustainability education – critically important dimensions of ESD research, but not within the scope of this chapter. Re-search on – say – the relative effect of different pedagogies, or how a learning environ-ment affects learning, may be thought of as basic research, but at another level, ESD research is often purposeful beyond the accumulation of understanding about educational processes.
- Full Text:
- Date Issued: 2015
- Authors: Lotz-Sisitka, Heila
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/437136 , vital:73345 , ISBN 9781315852249 , https://www.taylorfrancis.com/chapters/edit/10.4324/9781315852249-17/review-three-generations-critical-theory-heila-lotz-sisitka
- Description: To begin a review of the purpose(s) of ESD research, we must first ask the basic question of the purpose of research generally. Definitions of research normally centre on it comprising sys-tematic investigation which contributes to knowledge or under-standing of phenomena or a problem. A distinction is common-ly drawn between pure or basic research which focuses on understanding phenomena and issues, and applied research where the primary emphasis is on research which contributes to the solution of problems or some systemic improvement ra-ther than knowledge for its own sake. Some commentators see action research as a third category as it is predicated on the researcher being part of the research process which itself is committed to personal or social change. ESD research as an area of interest is perhaps unusual because it accommodates and crosses these categories. It also engages in philosophic research regarding cultural, worldview and ethical dimensions of sustainability education – critically important dimensions of ESD research, but not within the scope of this chapter. Re-search on – say – the relative effect of different pedagogies, or how a learning environ-ment affects learning, may be thought of as basic research, but at another level, ESD research is often purposeful beyond the accumulation of understanding about educational processes.
- Full Text:
- Date Issued: 2015
Absenting absence: Expanding zones of proximal development in environmental learning processes
- Authors: Lotz-Sisitka, Heila
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436939 , vital:73318 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: In this chapter I demonstrate that indigenous knowledge practice is com mensurate with critical realist scientific practice. Critical realism under labours for Western scien-tific knowledge, helping to bring its practice in line with its theory. In this paper I similarly underlabour for indigenous knowledge. I use examples from the Eastern Coast of Tan-zania to suggest that the kind of knowledge that is gener-ated through indigenous pro cesses is based on retroduc-tive and retrodictive reasoning (as well as induc tive and deductive reasoning) and is thus grounded in the theory development principles of DREI(C)/RRREI(C) which, ac-cording to Bhaskar (1993), is the basis for all scientific knowledge. The chapter therefore creates a basis for indi-viduals, groups, organiza tions, and institutions that are involved in the field of environment and sustainability edu-cation and have an indigenous knowledge component, to use the DREI(C)/RRREI(C) for learning and research pur-poses. In this way, they can assume the commensurablity of both Western scientific knowledge and indigenous knowledge. This work substantiates the signifi cance of indigenous knowledge as science in its own right, which pursues specified scientific principles and procedures to inform practice or praxis in the coastal learning environ-ment in a manner that may enhance social learning. There already exists a body of literature that regards indigenous knowledge as ‘local science’ (Sillitoe, 2007). However, I hope to expand this view by more closely aligning this ‘lo-cal science’ with the same prac tices used by science in general, where this science is defined according to critical realist principles.
- Full Text:
- Date Issued: 2015
- Authors: Lotz-Sisitka, Heila
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436939 , vital:73318 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: In this chapter I demonstrate that indigenous knowledge practice is com mensurate with critical realist scientific practice. Critical realism under labours for Western scien-tific knowledge, helping to bring its practice in line with its theory. In this paper I similarly underlabour for indigenous knowledge. I use examples from the Eastern Coast of Tan-zania to suggest that the kind of knowledge that is gener-ated through indigenous pro cesses is based on retroduc-tive and retrodictive reasoning (as well as induc tive and deductive reasoning) and is thus grounded in the theory development principles of DREI(C)/RRREI(C) which, ac-cording to Bhaskar (1993), is the basis for all scientific knowledge. The chapter therefore creates a basis for indi-viduals, groups, organiza tions, and institutions that are involved in the field of environment and sustainability edu-cation and have an indigenous knowledge component, to use the DREI(C)/RRREI(C) for learning and research pur-poses. In this way, they can assume the commensurablity of both Western scientific knowledge and indigenous knowledge. This work substantiates the signifi cance of indigenous knowledge as science in its own right, which pursues specified scientific principles and procedures to inform practice or praxis in the coastal learning environ-ment in a manner that may enhance social learning. There already exists a body of literature that regards indigenous knowledge as ‘local science’ (Sillitoe, 2007). However, I hope to expand this view by more closely aligning this ‘lo-cal science’ with the same prac tices used by science in general, where this science is defined according to critical realist principles.
- Full Text:
- Date Issued: 2015
Absenting the absence of parallel learning pathways for intermediate skills: The ‘missing middle' in the environmental sector in South Africa
- Authors: Ramsarup, Presha
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436964 , vital:73320 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: Environment and sustainable development are recognized for: their significance for the future of South Africa’s well-being; their complex, transversal nature; and their associated ‘new-ness’ within South African education and training systems. In a sector with relatively new occupations without clear learning pathways into jobs and where occupational contexts are rapid-ly changing with evolving skill needs, the chapter explores a critical realist dialectical view of learning pathways across sys-tems of work and learning. It highlights the need to develop more sophisticated understandings of learning pathways, and the way in which work, education and training systems inter-face to support the transitions needed for particular forms of work and learning. The chapter also explores how critical real-ist dialectics can help to explain more fully the absence of in-termediate pathways in the environment and sustainable de-velopment ‘sector’ in South Africa. It highlights the absences within the post-school provisioning system and through this analysis raises the patterns of emergence that characterize environmental learning pathways. This then advances an edu-cational critique that assists in the development of deeper knowledge of the object of the study (elements constituting learning pathways) in order to understand possibilities for change and to present opportunities for creating more seam-less environmental learning pathways into green jobs, enhanc-ing social justice potential and public good concerns.
- Full Text:
- Date Issued: 2015
- Authors: Ramsarup, Presha
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436964 , vital:73320 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: Environment and sustainable development are recognized for: their significance for the future of South Africa’s well-being; their complex, transversal nature; and their associated ‘new-ness’ within South African education and training systems. In a sector with relatively new occupations without clear learning pathways into jobs and where occupational contexts are rapid-ly changing with evolving skill needs, the chapter explores a critical realist dialectical view of learning pathways across sys-tems of work and learning. It highlights the need to develop more sophisticated understandings of learning pathways, and the way in which work, education and training systems inter-face to support the transitions needed for particular forms of work and learning. The chapter also explores how critical real-ist dialectics can help to explain more fully the absence of in-termediate pathways in the environment and sustainable de-velopment ‘sector’ in South Africa. It highlights the absences within the post-school provisioning system and through this analysis raises the patterns of emergence that characterize environmental learning pathways. This then advances an edu-cational critique that assists in the development of deeper knowledge of the object of the study (elements constituting learning pathways) in order to understand possibilities for change and to present opportunities for creating more seam-less environmental learning pathways into green jobs, enhanc-ing social justice potential and public good concerns.
- Full Text:
- Date Issued: 2015
Agathis bishopi (Hymenoptera: Braconidae) as a potential tool for detecting oranges infested with Thaumatotibia leucotreta (Lepidoptera: Tortricidae)
- Zimba, Kennedy J, Hill, Martin P, Moore, Sean D, Heshula, Unathi
- Authors: Zimba, Kennedy J , Hill, Martin P , Moore, Sean D , Heshula, Unathi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423955 , vital:72108 , xlink:href="https://doi.org/10.1007/s10905-015-9526-0"
- Description: In South Africa, Thaumatotibia leucotreta is a key pest of citrus impacting its production and trade. Detection of newly infested fruit by visual inspection is challenging and poses a risk of packing infested with healthy fruit for export. Agathis bishopi is a larval endoparasitoid of T. leucotreta, attacking early larval instars. Understanding how A. bishopi parasitoids locate fruit infested with their host is of interest for developing an efficient detector for T. leucotreta infested fruit. The response of female adult A. bishopi parasitoids to olfactory and visual cues associated with T. leucotreta infested fruit were evaluated using a Y-tube olfactometer and flight tunnel. Agathis bishopi parasitoids were strongly attracted to infested fruit over healthy fruit, either when only olfactory or combinations of visual and olfactory cues were offered. Among the four synthetic compounds tested, D-limonene and ocimene elicited a strong attraction to parasitoids with response rates of 92 % and 72 % respectively. A blend of four synthetic compounds simulating T. leucotreta infested fruit odour equally elicited strong attraction to parasitoids (84 % response rate). Attraction of parasitoids to infested fruit cues was heightened by prior experience, suggesting the occurrence of associative learning. Results from this study indicate that A. bishopi parasitoids mainly rely on olfactory cues in host habitat location and that D-limonene and ocimene are the major attractants in infested fruit volatiles. These findings and the potential for manipulating A. bishopi for detection of infested fruit in the packhouse are discussed.
- Full Text:
- Date Issued: 2015
- Authors: Zimba, Kennedy J , Hill, Martin P , Moore, Sean D , Heshula, Unathi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423955 , vital:72108 , xlink:href="https://doi.org/10.1007/s10905-015-9526-0"
- Description: In South Africa, Thaumatotibia leucotreta is a key pest of citrus impacting its production and trade. Detection of newly infested fruit by visual inspection is challenging and poses a risk of packing infested with healthy fruit for export. Agathis bishopi is a larval endoparasitoid of T. leucotreta, attacking early larval instars. Understanding how A. bishopi parasitoids locate fruit infested with their host is of interest for developing an efficient detector for T. leucotreta infested fruit. The response of female adult A. bishopi parasitoids to olfactory and visual cues associated with T. leucotreta infested fruit were evaluated using a Y-tube olfactometer and flight tunnel. Agathis bishopi parasitoids were strongly attracted to infested fruit over healthy fruit, either when only olfactory or combinations of visual and olfactory cues were offered. Among the four synthetic compounds tested, D-limonene and ocimene elicited a strong attraction to parasitoids with response rates of 92 % and 72 % respectively. A blend of four synthetic compounds simulating T. leucotreta infested fruit odour equally elicited strong attraction to parasitoids (84 % response rate). Attraction of parasitoids to infested fruit cues was heightened by prior experience, suggesting the occurrence of associative learning. Results from this study indicate that A. bishopi parasitoids mainly rely on olfactory cues in host habitat location and that D-limonene and ocimene are the major attractants in infested fruit volatiles. These findings and the potential for manipulating A. bishopi for detection of infested fruit in the packhouse are discussed.
- Full Text:
- Date Issued: 2015
Agathis bishopi, a larval parasitoid of false codling moth Thaumatotibia leucotreta: laboratory rearing and effect of adult food on parasitism and longevity
- Zimba, Kennedy J, Moore, Sean D, Heshula, Lelethu U P, Hill, Martin P
- Authors: Zimba, Kennedy J , Moore, Sean D , Heshula, Lelethu U P , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406985 , vital:70328 , xlink:href="https://hdl.handle.net/10520/EJC185849"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae) is a koinobiont larval endoparasitoid of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of economic importance on citrus in South Africa. In the field Agathis bishopi was found to parasitise up to 34 % of FCM larvae in fruit, reflecting reasonable biocontrol potential. Improving the rearing of A. bishopi would therefore complement the existing biocontrol strategies for FCM. In several parasitic wasps, sugar concentration and feeding duration has been shown to influence parasitism and longevity. However, their effect on parasitism and longevity of A. bishopi is unknown. In the present study a rearing protocol for A. bishopi is described, including evaluation of the effects of honey concentration on parasitoid longevity. On average, 18.2%of FCM larvae in rearing containers were parasitised under the rearing protocol described. Cotton wool, instead of paper towelling, as honey carrier for feeding parasitoids in rearing containers significantly increased parasitism and yield of offspring. Furthermore, longevity significantly increased with higher concentrations of honey. Maximum lifespan duration for male and female parasitoids was achieved when parasitoids were fed on 36 % (w/v) honey. Results from this study indicate that A. bishopi requires a sufficient concentration of sugar, coupled with frequent and prolonged feeding on a cotton wool substrate, in order to achieve maximum parasitism and longevity. Such information provides a basis for optimising mass-rearing and longevity of A. bishopi and parasitism of FCM in orchards.
- Full Text:
- Date Issued: 2015
- Authors: Zimba, Kennedy J , Moore, Sean D , Heshula, Lelethu U P , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406985 , vital:70328 , xlink:href="https://hdl.handle.net/10520/EJC185849"
- Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae) is a koinobiont larval endoparasitoid of false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of economic importance on citrus in South Africa. In the field Agathis bishopi was found to parasitise up to 34 % of FCM larvae in fruit, reflecting reasonable biocontrol potential. Improving the rearing of A. bishopi would therefore complement the existing biocontrol strategies for FCM. In several parasitic wasps, sugar concentration and feeding duration has been shown to influence parasitism and longevity. However, their effect on parasitism and longevity of A. bishopi is unknown. In the present study a rearing protocol for A. bishopi is described, including evaluation of the effects of honey concentration on parasitoid longevity. On average, 18.2%of FCM larvae in rearing containers were parasitised under the rearing protocol described. Cotton wool, instead of paper towelling, as honey carrier for feeding parasitoids in rearing containers significantly increased parasitism and yield of offspring. Furthermore, longevity significantly increased with higher concentrations of honey. Maximum lifespan duration for male and female parasitoids was achieved when parasitoids were fed on 36 % (w/v) honey. Results from this study indicate that A. bishopi requires a sufficient concentration of sugar, coupled with frequent and prolonged feeding on a cotton wool substrate, in order to achieve maximum parasitism and longevity. Such information provides a basis for optimising mass-rearing and longevity of A. bishopi and parasitism of FCM in orchards.
- Full Text:
- Date Issued: 2015
Amoxicillin removal from aqueous media using multi-walled carbon nanotubes
- Mohammadi, Ali, Kazemipour, Maryam, Walker, Roderick B, Ansari, Mehdi
- Authors: Mohammadi, Ali , Kazemipour, Maryam , Walker, Roderick B , Ansari, Mehdi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183861 , vital:44076 , xlink:href="https://doi.org/10.1080/1536383X.2013.866944"
- Description: Multi-walled carbon nanotubes (MWCNT) were used to separate amoxicillin from aqueous media. The parameters affecting amoxicillin adsorption such as pH, temperature, time, interferences of similar molecules, and the amount of adsorbent used were studied. Amoxicillin adsorption using MWCNT was compared to that using Fullerene C60 and activated carbon (AC). The adsorption efficiency of 0.1 and 0.2 g of MWCNT using in a continuous mode were 86.5% and 87.9%, respectively. Evaluation of the adsorbent capacity showed that each gram of MWCNT can absorb 22.9 mg amoxicillin. The effect of pH was studied over the range 2–8 and revealed that adsorption of the amoxicillin at the initial pH of 4.6 was more effective than any other pH. The adsorption of amoxicillin on MWCNT was much greater than Fullerene C60 and AC. Adsorption data showed that they were best fitted to the Langmuir isotherm.
- Full Text:
- Date Issued: 2015
- Authors: Mohammadi, Ali , Kazemipour, Maryam , Walker, Roderick B , Ansari, Mehdi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183861 , vital:44076 , xlink:href="https://doi.org/10.1080/1536383X.2013.866944"
- Description: Multi-walled carbon nanotubes (MWCNT) were used to separate amoxicillin from aqueous media. The parameters affecting amoxicillin adsorption such as pH, temperature, time, interferences of similar molecules, and the amount of adsorbent used were studied. Amoxicillin adsorption using MWCNT was compared to that using Fullerene C60 and activated carbon (AC). The adsorption efficiency of 0.1 and 0.2 g of MWCNT using in a continuous mode were 86.5% and 87.9%, respectively. Evaluation of the adsorbent capacity showed that each gram of MWCNT can absorb 22.9 mg amoxicillin. The effect of pH was studied over the range 2–8 and revealed that adsorption of the amoxicillin at the initial pH of 4.6 was more effective than any other pH. The adsorption of amoxicillin on MWCNT was much greater than Fullerene C60 and AC. Adsorption data showed that they were best fitted to the Langmuir isotherm.
- Full Text:
- Date Issued: 2015
Baculovirus-based strategies for the management of insect pests: a focus on development and application in South Africa
- Knox, Caroline M, Moore, Sean D, Luke, Garry, Hill, Martin P
- Authors: Knox, Caroline M , Moore, Sean D , Luke, Garry , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416829 , vital:71389 , xlink:href="https://doi.org/10.1080/09583157.2014.949222"
- Description: There is growing concern among governments, scientists, agricultural practitioners and the general public regarding the negative implications of widespread synthetic chemical pesticide application for the control of crop pests. As a result, baculovirus biopesticides are gaining popularity as components of integrated pest management (IPM) programmes in many countries despite several disadvantages related to slow speed of kill, limited host range and complex large scale production. In South Africa, baculoviruses are incorporated into IPM programmes for the control of crop pests in the field, and recent bioprospecting has led to the characterisation of several novel isolates with the potential to be formulated as commercial products. This contribution will provide an overview of the use of baculoviruses against insect pests in South Africa, as well as research and development efforts aimed at broadening their application as biocontrol agents. Challenges faced by researchers in developmental projects as well as potential users of baculoviruses as biopesticides in the field are also discussed.
- Full Text:
- Date Issued: 2015
- Authors: Knox, Caroline M , Moore, Sean D , Luke, Garry , Hill, Martin P
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/416829 , vital:71389 , xlink:href="https://doi.org/10.1080/09583157.2014.949222"
- Description: There is growing concern among governments, scientists, agricultural practitioners and the general public regarding the negative implications of widespread synthetic chemical pesticide application for the control of crop pests. As a result, baculovirus biopesticides are gaining popularity as components of integrated pest management (IPM) programmes in many countries despite several disadvantages related to slow speed of kill, limited host range and complex large scale production. In South Africa, baculoviruses are incorporated into IPM programmes for the control of crop pests in the field, and recent bioprospecting has led to the characterisation of several novel isolates with the potential to be formulated as commercial products. This contribution will provide an overview of the use of baculoviruses against insect pests in South Africa, as well as research and development efforts aimed at broadening their application as biocontrol agents. Challenges faced by researchers in developmental projects as well as potential users of baculoviruses as biopesticides in the field are also discussed.
- Full Text:
- Date Issued: 2015
Beauveria and Metarhizium against false codling moth (Lepidoptera: Tortricidae): a step towards selecting isolates for potential development of a mycoinsecticide
- Coombes, Candice A, Hill, Martin P, Moore, Sean D, Dames, Joanna F, Fullard, T
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405757 , vital:70203 , xlink:href="https://hdl.handle.net/10520/EJC167505"
- Description: False codling moth, Thaumatotibia leucotreta Meyrick (1912) (Lepidoptera: Tortricidae), can cause both pre- and post-harvest damage to citrus fruit. Not only can this result in reduced crop yield, but more importantly because of the moth's endemism to sub-Saharan Africa, it is classified as a phytosanitary pest by many export markets. An entire consignment of citrus may be rejected in the presence of a single moth (Moore 2012). Since the bulk of citrus fruit production in South Africa is exported, the control of T. leucotreta is critical (Citrus Growers Association, South Africa 2012). Traditionally, control has been achieved through the use of chemical insecticides; however, residue restrictions, resistance development and concerns about environmental pollution have substantially reduced the dependence on chemical pesticides in citrus. Research on T. leucotreta control has therefore focused on the use of biological organisms (e.g. parasitoids and viruses), which are used as control agents within an integrated pest management (IPM) programme in citrus. These biological control agents, however, only targeted the aboveground life stages of the pest, not the soil-dwelling life stages (late fifth instars, prepupae, pupae), which is the subject of this contribution (Moore 2012).
- Full Text:
- Date Issued: 2015
- Authors: Coombes, Candice A , Hill, Martin P , Moore, Sean D , Dames, Joanna F , Fullard, T
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/405757 , vital:70203 , xlink:href="https://hdl.handle.net/10520/EJC167505"
- Description: False codling moth, Thaumatotibia leucotreta Meyrick (1912) (Lepidoptera: Tortricidae), can cause both pre- and post-harvest damage to citrus fruit. Not only can this result in reduced crop yield, but more importantly because of the moth's endemism to sub-Saharan Africa, it is classified as a phytosanitary pest by many export markets. An entire consignment of citrus may be rejected in the presence of a single moth (Moore 2012). Since the bulk of citrus fruit production in South Africa is exported, the control of T. leucotreta is critical (Citrus Growers Association, South Africa 2012). Traditionally, control has been achieved through the use of chemical insecticides; however, residue restrictions, resistance development and concerns about environmental pollution have substantially reduced the dependence on chemical pesticides in citrus. Research on T. leucotreta control has therefore focused on the use of biological organisms (e.g. parasitoids and viruses), which are used as control agents within an integrated pest management (IPM) programme in citrus. These biological control agents, however, only targeted the aboveground life stages of the pest, not the soil-dwelling life stages (late fifth instars, prepupae, pupae), which is the subject of this contribution (Moore 2012).
- Full Text:
- Date Issued: 2015
Benzimidazole or Diamide From a Reaction of Diamines and Carboxylic Acids or Acid Chlorides: Crystal Structures and Theoretical Studies
- Odame, Felix, Hosten, Eric C, Betz, Richard, Lobb, Kevin A, Tshentu, Zenixole R
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447938 , vital:74685 , xlink:href="https://pdfs.semanticscholar.org/bf5a/ce94c9436f40059793eb988e08da8ef09886.pdf"
- Description: A reaction of an acid chloride with a diamine yielded a diamide. m-Toluic acid was chlorinated to m-toluoyl chloride and subsequently reacted with 4-methyl-o-phenylenediamine in pyridine to obtain 3-methyl-N-[2-(3-methylbenzamido)phenylbenzamide (I). 2-(3-Methylphenyl)-1H-benzimidazole (II) has been obtained upon reacting o-phenylenediamine with m-toluic acid in polyphosphoric acid and toluene. The compounds have been characterized by IR, NMR, microanalyses and GC-MS. The crystal structures of the compounds have been discussed. DFT calculations of the frontier orbitals of the precursor compounds have been carried out to ascertain the groups that contribute to the HOMO and LUMO, and to study their contribution to the reactivity in the formation of the diamides and benzimidazoles. The synthesis of the amide from a diamine was seen to be favoured in the presence of a good leaving group attached to the carbonyl as in the case of acid chloride. However, the synthesis of benzimidazoles was found to be favoured in the presence of an excess of a protonating agent and high temperature.
- Full Text:
- Date Issued: 2015
- Authors: Odame, Felix , Hosten, Eric C , Betz, Richard , Lobb, Kevin A , Tshentu, Zenixole R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/447938 , vital:74685 , xlink:href="https://pdfs.semanticscholar.org/bf5a/ce94c9436f40059793eb988e08da8ef09886.pdf"
- Description: A reaction of an acid chloride with a diamine yielded a diamide. m-Toluic acid was chlorinated to m-toluoyl chloride and subsequently reacted with 4-methyl-o-phenylenediamine in pyridine to obtain 3-methyl-N-[2-(3-methylbenzamido)phenylbenzamide (I). 2-(3-Methylphenyl)-1H-benzimidazole (II) has been obtained upon reacting o-phenylenediamine with m-toluic acid in polyphosphoric acid and toluene. The compounds have been characterized by IR, NMR, microanalyses and GC-MS. The crystal structures of the compounds have been discussed. DFT calculations of the frontier orbitals of the precursor compounds have been carried out to ascertain the groups that contribute to the HOMO and LUMO, and to study their contribution to the reactivity in the formation of the diamides and benzimidazoles. The synthesis of the amide from a diamine was seen to be favoured in the presence of a good leaving group attached to the carbonyl as in the case of acid chloride. However, the synthesis of benzimidazoles was found to be favoured in the presence of an excess of a protonating agent and high temperature.
- Full Text:
- Date Issued: 2015
Bhaskar and collective action: Using laminations to structure a literature review of collective action and water management
- Authors: Burt, Jane C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436978 , vital:73321 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.
- Full Text:
- Date Issued: 2015
- Authors: Burt, Jane C
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/436978 , vital:73321 , ISBN 9781315660899 , https://www.routledge.com/Critical-Realism-Environmental-Learning-and-Social-Ecological-Change/Price-Lotz-Sistka/p/book/9780367597689
- Description: This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.This chapter describes the use of Bhaskar’s lamination to make sense of the vast literature on collective action. The liter-ature review in the chapter was part of a broader study that in-vestigated collective action as essential for attaining the princi-ples of equity and sustainability set out in the post-apartheid South African Water Act. A laminated analysis of the literature revealed important insights such as: when dealing with collec-tive action we need to appreciate that all the levels of reality are acting simultaneously on a given context and cannot be resolved in isolation; collective action is inhibited or con-strained at different levels and scales by different things; and collective action is not suspended in a fixed context and can-not be encouraged by following a set formula. These insights point to the importance of learning to adapt as a core principle of collective action. Drawing on this research and experience of how collective action can be supported or inhibited gives insight into understanding our current limitations in supporting collective action and in understanding the kinds of collective action encounters that are occurring in catchments in South Africa. These understandings have implications for how we consider learning, and the potential contributions of learning-led change.
- Full Text:
- Date Issued: 2015
Biodiversity and nutrition
- Hunter, D, Burlingame, B, Remans, Roseline, Borelli, Teresa, Cogill, Bruce, Coradin, Lidio, Golden, C D, Jamnadass, Ramni H, Kehlenbeck, K, Kennedy, G, Kuhnlein, H V, McMullin, S, Myers, S, Silva, A J R, Saha, M, Scheerer, L, Shackleton, Charlie M, Neves Soares Oliviera, C, Termote, Celine, Teofili, C, Thilsted, Shakuntala H, Valenti, R
- Authors: Hunter, D , Burlingame, B , Remans, Roseline , Borelli, Teresa , Cogill, Bruce , Coradin, Lidio , Golden, C D , Jamnadass, Ramni H , Kehlenbeck, K , Kennedy, G , Kuhnlein, H V , McMullin, S , Myers, S , Silva, A J R , Saha, M , Scheerer, L , Shackleton, Charlie M , Neves Soares Oliviera, C , Termote, Celine , Teofili, C , Thilsted, Shakuntala H , Valenti, R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434014 , vital:73026 , ISBN 978 92 4 150853 7 , https://hdl.handle.net/10568/67423
- Description: Malnutrition remains one of the greatest global health challenges we face and women and children are its most visible and vulnerable victims. Agricultural production is theoretically able to feed the world’s population in terms of calories (FAOSTAT, 2014), yet it is estimated that half the world’s population still suffers from one or more forms of malnutrition. In all its forms, malnutrition is closely linked to disease – as both a cause and effect – and it is the single largest contributor to the global burden of disease (WHO 2012a).
- Full Text:
- Date Issued: 2015
- Authors: Hunter, D , Burlingame, B , Remans, Roseline , Borelli, Teresa , Cogill, Bruce , Coradin, Lidio , Golden, C D , Jamnadass, Ramni H , Kehlenbeck, K , Kennedy, G , Kuhnlein, H V , McMullin, S , Myers, S , Silva, A J R , Saha, M , Scheerer, L , Shackleton, Charlie M , Neves Soares Oliviera, C , Termote, Celine , Teofili, C , Thilsted, Shakuntala H , Valenti, R
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434014 , vital:73026 , ISBN 978 92 4 150853 7 , https://hdl.handle.net/10568/67423
- Description: Malnutrition remains one of the greatest global health challenges we face and women and children are its most visible and vulnerable victims. Agricultural production is theoretically able to feed the world’s population in terms of calories (FAOSTAT, 2014), yet it is estimated that half the world’s population still suffers from one or more forms of malnutrition. In all its forms, malnutrition is closely linked to disease – as both a cause and effect – and it is the single largest contributor to the global burden of disease (WHO 2012a).
- Full Text:
- Date Issued: 2015
Black-boxing and the politics of parliamentary oversight in South Africa
- Siebörger, Ian, Adendorf, Ralph D
- Authors: Siebörger, Ian , Adendorf, Ralph D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433497 , vital:72976 , ISBN 978-9027206565 , https://doi.org/10.1075/dapsac.65
- Description: We investigate a parliamentary committee meeting overseeing a randomly chosen state-owned entity, in order to track the processes of knowledge production that occur in parliamentary oversight. The entity’s representatives use “epistemological condensation” (Maton 2014:130) to present the information they give to the MPs as incontestable, effectively “black-boxing” it. “Black-boxing” (Latour 1987) is a process which presents knowledge in such a way that very little room is left for questioning it. The committee members also use “epistemological rarefaction” (Maton 2014:130) to open the black box of the presentation and question its contents, challenging the practices of the entity.
- Full Text:
- Date Issued: 2015
- Authors: Siebörger, Ian , Adendorf, Ralph D
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/433497 , vital:72976 , ISBN 978-9027206565 , https://doi.org/10.1075/dapsac.65
- Description: We investigate a parliamentary committee meeting overseeing a randomly chosen state-owned entity, in order to track the processes of knowledge production that occur in parliamentary oversight. The entity’s representatives use “epistemological condensation” (Maton 2014:130) to present the information they give to the MPs as incontestable, effectively “black-boxing” it. “Black-boxing” (Latour 1987) is a process which presents knowledge in such a way that very little room is left for questioning it. The committee members also use “epistemological rarefaction” (Maton 2014:130) to open the black box of the presentation and question its contents, challenging the practices of the entity.
- Full Text:
- Date Issued: 2015
Book Review Growing the next generation of researchers: A handbook for emerging researchers and their mentors, Holness, L
- Motshoane, Puleng, Muthama, Evelyn, McKenna, Sioux
- Authors: Motshoane, Puleng , Muthama, Evelyn , McKenna, Sioux
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187205 , vital:44579 , xlink:href="https://doi.org/10.14426/cristal.v3i2.56"
- Description: South Africa urgently needs more researchers (NRF, 2008; NDP, 2011). We also need a transformation in the demographics of our researchers. One indicator of this is that currently only 14% of university professors are black African, and only 2% are black African females (DHET, 2012). The Staffing South Africa's Universities Framework includes a number of initiatives to drive the process of growing the next generation of academics. For example, the nGAP project has inserted 125 new posts into the higher education system in 2015, with more to follow. This project allows for new academics to undertake postgraduate study and develop as teachers and researchers through mentorship, a reduced teaching load and so on.
- Full Text:
- Date Issued: 2015
- Authors: Motshoane, Puleng , Muthama, Evelyn , McKenna, Sioux
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187205 , vital:44579 , xlink:href="https://doi.org/10.14426/cristal.v3i2.56"
- Description: South Africa urgently needs more researchers (NRF, 2008; NDP, 2011). We also need a transformation in the demographics of our researchers. One indicator of this is that currently only 14% of university professors are black African, and only 2% are black African females (DHET, 2012). The Staffing South Africa's Universities Framework includes a number of initiatives to drive the process of growing the next generation of academics. For example, the nGAP project has inserted 125 new posts into the higher education system in 2015, with more to follow. This project allows for new academics to undertake postgraduate study and develop as teachers and researchers through mentorship, a reduced teaching load and so on.
- Full Text:
- Date Issued: 2015
Book Review: A Renegade called Simphiwe
- Authors: Magadla, Siphokazi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298595 , vital:57719 , xlink:href="https://doi.org/10.1177/0021909614533638"
- Description: A Renegade called Simphiwe is a “creative-intellectual portrait” of the public (and private) life of the musician Simphiwe Dana (p. 150). Gqola defines the book as “one writer’s engagement with the Simphiwe Dana of the South African public imagination [who]… troubles many categories of belonging in the South African public imagination in remarkable ways” (pp. 17, 32). The book comes at a poignant time as South Africa reflects on the success and challenges of the first 20 years of democracy. Fittingly, Gqola positions Dana within a long tradition of griots in Africa whose art always spoke truth to power.
- Full Text:
- Date Issued: 2015
- Authors: Magadla, Siphokazi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298595 , vital:57719 , xlink:href="https://doi.org/10.1177/0021909614533638"
- Description: A Renegade called Simphiwe is a “creative-intellectual portrait” of the public (and private) life of the musician Simphiwe Dana (p. 150). Gqola defines the book as “one writer’s engagement with the Simphiwe Dana of the South African public imagination [who]… troubles many categories of belonging in the South African public imagination in remarkable ways” (pp. 17, 32). The book comes at a poignant time as South Africa reflects on the success and challenges of the first 20 years of democracy. Fittingly, Gqola positions Dana within a long tradition of griots in Africa whose art always spoke truth to power.
- Full Text:
- Date Issued: 2015
Book Review: Global Governance and the New Wars
- Authors: Magadla, Siphokazi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298640 , vital:57723 , xlink:href="https://doi.org/10.1080/02589346.2015.1008676"
- Description: Mark Duffield's second edition of ‘Global Governance and the New Wars’ offers an important and biting critique of how different actors within the security and development discourse have adapted to the various transformations of war in the post-cold war era. In this picture drawn by Duffield, the power of states in the South continues to be eroded by an exclusionary market that is driven by the global political economy wherein state's development and security responsibilities are increasingly assumed by non-state actors (predominately constituted by Western aid agencies). Those who fall outside the bounds of the state, development and humanitarian aid agencies can be found operating in an expanding shadow economy that is also shaped by a global dynamics which make the conditions for ‘network war' possible. In this context, the lines between ‘war' and peace” are difficult to distinguish. Overall, the book paints a depressing picture on the lack of substantive changes in the livelihoods of the poor as attention has been directed to discussions about ‘new wars' or altered forms of violence that have characterized the post-cold war era. The book unforgivingly exposes the failures of the discursive changes post-cold war to reconceptualize development and security in terms that move beyond description and into substantive change especially regarding shifting the development discourse from its historic modernizing impulses.
- Full Text:
- Date Issued: 2015
- Authors: Magadla, Siphokazi
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298640 , vital:57723 , xlink:href="https://doi.org/10.1080/02589346.2015.1008676"
- Description: Mark Duffield's second edition of ‘Global Governance and the New Wars’ offers an important and biting critique of how different actors within the security and development discourse have adapted to the various transformations of war in the post-cold war era. In this picture drawn by Duffield, the power of states in the South continues to be eroded by an exclusionary market that is driven by the global political economy wherein state's development and security responsibilities are increasingly assumed by non-state actors (predominately constituted by Western aid agencies). Those who fall outside the bounds of the state, development and humanitarian aid agencies can be found operating in an expanding shadow economy that is also shaped by a global dynamics which make the conditions for ‘network war' possible. In this context, the lines between ‘war' and peace” are difficult to distinguish. Overall, the book paints a depressing picture on the lack of substantive changes in the livelihoods of the poor as attention has been directed to discussions about ‘new wars' or altered forms of violence that have characterized the post-cold war era. The book unforgivingly exposes the failures of the discursive changes post-cold war to reconceptualize development and security in terms that move beyond description and into substantive change especially regarding shifting the development discourse from its historic modernizing impulses.
- Full Text:
- Date Issued: 2015