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(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.
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Date Issued: 2015

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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.
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Date Issued: 2015

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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.
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Date Issued: 2015

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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.
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Date Issued: 2015

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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.
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Date Issued: 2015

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A great Olive Schreiner question-brilliantly answered The World's Great Question: Olive Schreiner's South African Letters 1889-1920, Liz Stanley and Andrea Salter (Eds.)

- Walters, Paul S

Authors: Walters, Paul S
Date: 2015
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/458335 , vital:75733 , https://hdl.handle.net/10520/EJC176978
Description: Thus Samuel Cron Cronwright-Schreiner in the "Preface" to his Life of Olive Schreiner (1924). Even at the remove of more than 90 years, these read as extremely strong claims. Volumes could be written about what Cronwright might/might not have meant by the "correctness" of his biography of his famous wife as well as the deconstruction of such loaded terms as "unusual personality" and "so complex and baffling a human being." Ten years after the publication of the Life, Cronwright (1934) himself unintentionally provided a further intriguing sense of what that "correctness" might in fact have concealed in the last letter he wrote to Havelock Ellis (10 Sept 1934, HRHRC).
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Date Issued: 2015

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A high-level architecture for efficient packet trace analysis on gpu co-processors

- Nottingham, Alastair, Irwin, Barry V W

Authors: Nottingham, Alastair , Irwin, Barry V W
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/429572 , vital:72623 , 10.1109/ISSA.2013.6641052
Description: This paper proposes a high-level architecture to support efficient, massively parallel packet classification, filtering and analysis using commodity Graphics Processing Unit (GPU) hardware. The proposed architecture aims to provide a flexible and efficient parallel packet processing and analysis framework, supporting complex programmable filtering, data mining operations, statistical analysis functions and traffic visualisation, with minimal CPU overhead. In particular, this framework aims to provide a robust set of high-speed analysis functionality, in order to dramatically reduce the time required to process and analyse extremely large network traces. This architecture derives from initial research, which has shown GPU co-processors to be effective in accelerating packet classification to up to tera-bit speeds with minimal CPU overhead, far exceeding the bandwidth capacity between standard long term storage and the GPU device. This paper provides a high-level overview of the proposed architecture and its primary components, motivated by the results of prior research in the field.
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Date Issued: 2013

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A kernel-driven framework for high performance internet routing simulation

- Herbert, Alan, Irwin, Barry V W

Authors: Herbert, Alan , Irwin, Barry V W
Date: 2013
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/429585 , vital:72624 , 10.1109/ISSA.2013.6641048
Description: The ability to provide the simulation of packets traversing an internet path is an integral part of providing realistic simulations for network training, and cyber defence exercises. This paper builds on previous work, and considers an in-kernel approach to solving the routing simulation problem. The inkernel approach is anticipated to allow the framework to be able to achieve throughput rates of 1GB/s or higher using commodity hardware. Processes that run outside the context of the kernel of most operating system require context switching to access hardware and kernel modules. This leads to considerable delays in the processes, such as network simulators, that frequently access hardware such as hard disk accesses and network packet handling. To mitigate this problem, as experienced with earlier implementations, this research looks towards implementing a kernel module to handle network routing and simulation within a UNIX based system. This would remove delays incurred from context switching and allows for direct access to the hardware components of the host.
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Date Issued: 2013

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A review of three generations of critical theory: Towards conceptualising critical HESD research

- Lotz-Sisitka, Heila

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.
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Date Issued: 2015

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Absenting absence: Expanding zones of proximal development in environmental learning processes

- Lotz-Sisitka, Heila

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.
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Date Issued: 2015

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Absenting the absence of parallel learning pathways for intermediate skills: The ‘missing middle' in the environmental sector in South Africa

- Ramsarup, Presha

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.
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Date Issued: 2015

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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.
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Date Issued: 2015

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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.
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Date Issued: 2015

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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.
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Date Issued: 2015

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Applied theatre research. Radical departures

- Sutherland, Alexandra

Authors: Sutherland, Alexandra
Date: 2015
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/468527 , vital:77087 , https://doi.org/10.1080/10137548.2015.1085255
Description: This book is part of the Applied Theatre series, which presents scholarship on different foci around applied theatre practices. The seven case studies of how applied theatre practices can be framed as research methodologies are practically and theoretically useful for students, practitioners and scholars engaged in community-driven, socially engaged theatre work. The book argues a particular approach to arts based research which offers alternatives to traditional research tools such as ‘the interview’ (which often result in participants giving a researcher what they think they want to know or hear) and provides a range of aesthetic research methodologies that aim to harness the language of theatre and performance as an empowering and resistant research tool.
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Date Issued: 2015

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Assessing ecosystem response to multiple disturbances and climate change in South Africa using ground-and satellite-based measurements and model

- Kutsch, Werner L, Falge, E M, Brümmer, Christian, Mukwashi, K, Schmullius, C, Hüttich, C, Odipo, V, Scholes, Robert J, Mudau, A, Midgley, Guy F, Stevens, N, Hickler, Thomas, Scheiter, Simon, Martens, C, Twine, Wayne, Iiyambo, T, Bradshaw, Karen L, Lück, W, Lenfers, Ulfia A, Thiel-Clemen, T

Authors: Kutsch, Werner L , Falge, E M , Brümmer, Christian , Mukwashi, K , Schmullius, C , Hüttich, C , Odipo, V , Scholes, Robert J , Mudau, A , Midgley, Guy F , Stevens, N , Hickler, Thomas , Scheiter, Simon , Martens, C , Twine, Wayne , Iiyambo, T , Bradshaw, Karen L , Lück, W , Lenfers, Ulfia A , Thiel-Clemen, T
Date: 2015
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/475183 , vital:77782 , xlink:href="https://ieeexplore.ieee.org/abstract/document/9856380"
Description: Sub-Saharan Africa currently experiences rapidly growing human population, intrinsically tied to substantial changes in land use on shrubland, savanna and mixed woodland ecosystems due to over-exploitation. Significant conversions driving degradation, affecting fire frequency and water availability, and fueling climate change are expected to increase in the immediate future. However, measured data of greenhouse gas emissions as affected by land use change are scarce to entirely lacking from this region. The project 'Adaptive Resilience of Southern African Ecosystems' (ARS AfricaE) conducts research and develops scenarios of ecosystem development under climate change, for management support in conservation or for planning rural area development. This will be achieved by (1) creation of a network of research clusters (paired sites with natural and altered vegetation) along an aridity gradient in South Africa for ground-based micrometeorological in-situ measurements of energy and matter fluxes, (2) linking biogeochemical functions with ecosystem structure, and eco-physiological properties, (3) description of ecosystem disturbance (and recovery) in terms of ecosystem function such as carbon balance components and water use efficiency, (4) set-up of individual-based models to predict ecosystem dynamics under (post) disturbance managements, (5) combination with long-term landscape dynamic information derived from remote sensing and aerial photography, and (6) development of sustainable management strategies for disturbed ecosystems and land use change. Emphasis is given on validation (by a suite of field measurements) of estimates obtained from eddy covariance, model approaches and satellite derivations.
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Date Issued: 2015

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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.
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Date Issued: 2015

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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).
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Date Issued: 2015

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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.
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Date Issued: 2015

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