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Mulch tower treatment system Part I: Overall performance in greywater treatment

  • Authors: Zuma, Bongumusa M , Tandlich, Roman , Whittington-Jones, Kevin J , Burgess, Jo E
  • Date: 2009
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/71537 , vital:29862 , https://doi.org/10.1016/j.desal.2008.03.030
  • Description: A mulch tower (MT) system for greywater treatment is introduced in this paper. Materials used to assemble the MT system included mulch, coarse sand, fine and coarse gravel. Limited removal efficiency of the MT system was demonstrated for alkalinity, total hardness, pH, Cl–, PO43–, NH4+, and SO42–, with the estimated cumulative removals ranging from 7 to 12%. Intermediate removal efficiency was observed for chemical oxygen demand (COD), NO3–, and S2– with the estimated cumulative removals ranging from 24 to 28%. The highest removal efficiency was observed for the total suspended solids (TSS) with the estimated cumulative removal equal to 52%. Given the minute residence time in the MT system, the results obtained were promising and justify scale-up studies for potential on-site applications. The MT effluent did not meet hygienic norms with respect to the faecal coliform concentration (FC) and the total coliform concentration (TC), and further effluent treatment is required before any discharge or reuse of the treated greywater. Further research should focus on characterisation of the microbial community of the MT, and the fate of Cl–, PO43–, NH4+, and SO42–.
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  • Date Issued: 2009

Synthesis, structure and in vitro anti-trypanosomal activity of non-toxic Arylpyrrole-Based Chalcone derivatives:

  • Authors: Zulu, Ayanda I , Oderinlo, Ogunyemi O , Kruger, Cuan , Isaacs, Michelle , Hoppe, Heinrich C , Smith, Vincent J , Veale, Clinton G L , Khanye, Setshaba D
  • Date: 2020
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/179017 , vital:40096 , https://doi.org/10.3390/molecules25071668
  • Description: With an intention of identifying chalcone derivatives exhibiting anti-protozoal activity, a cohort of relatively unexplored arylpyrrole-based chalcone derivatives were synthesized in moderate to good yields. The resultant compounds were evaluated in vitro for their potential activity against a cultured Trypanosoma brucei brucei 427 strain. Several compounds displayed mostly modest in vitro anti-trypanosomal activity with compounds 10e and 10h emerging as active candidates with IC50 values of 4.09 and 5.11 µM, respectively. More importantly, a concomitant assessment of their activity against a human cervix adenocarcinoma (HeLa) cell line revealed that these compounds are non-toxic.
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  • Date Issued: 2020

Comparative phototransformation of environmental pollutants using metallophthalocyanines supported on electrospun polymer fibers

  • Authors: Zugle, Ruphino , Nyokong, Tebello
  • Date: 2013
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/190509 , vital:45001 , xlink:href="https://doi.org/10.1002/app.38381"
  • Description: The fluorescence and photoactivity of a series of Zn and Lu phthalocyanine complexes incorporated in various polymer fibers were investigated for the phototransformation of 4-chlorophenol, 4-nitrophenol, and methyl orange. The phthalocyanine complexes functionalized on polystyrene and polysulfone polymer fibers could be applied in the degradation of 4-chlorophenol, 4-nitrophenol, and methyl orange with 4-chlorophenol being much more susceptible to degradation while methyl orange was the least. Also polymer fibers of polystyrene were found to be reusable.
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  • Date Issued: 2013

Zinc (II) 2, 9, 16, 23-tetrakis [4-(N-methylpyridyloxy)]-phthalocyanine anchored on an electrospun polysulfone polymer fiber: Application for photosensitized conversion of methyl orange

  • Authors: Zugle, Ruphino , Nyokong, Tebello
  • Date: 2013
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/232741 , vital:50020 , xlink:href="https://doi.org/10.1016/j.molcata.2012.10.001"
  • Description: In this work, a comparative study of photodegradation of methyl orange, an azo dye, in homogeneous aqueous solution of a quarternized cationic zinc phthalocyanine and a heterogeneous catalytic system based on the same phthalocyanine anchored on polysulfone polymer fiber is presented. In both cases, conversion involved the azo bond of the dye with no detectable opening up of the aromatic benzene rings. The reaction kinetics in both cases were consistent with first order with the conversion occurring in the homogeneous system being faster than when the functionalized polymer fiber was used. The reaction products consisted of a coupling product as well as a series of oligopolymeric products.
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  • Date Issued: 2013

Electrospun polyacrylic acid polymer fibers functionalized with metallophthalocyanines for photosensitizing and gas sensing applications

  • Authors: Zugle, Ruphino , Nyokong, Tebello
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/243543 , vital:51162 , xlink:href="https://doi.org/10.1080/10601325.2012.662006"
  • Description: The photophysical and photochemical properties of tetraaminophthalocyanine complexes of lutetium and zinc covalently linked to polyacrylic acid were studied alongside those of unsubstituted zinc phthalocyanine within the same polymeric fiber matrix. All three phthalocyanines within the solid fiber matrices showed photoactivity by the generation of singlet oxygen as was observed in solution. The fluorescence behaviors of the composite fibers equally parallel those in solution. For the unsubstituted zinc phthalocyanine composite, the fiber showed fluorescence quenching on interaction with gaseous nitrogen dioxide similar to that in DMF and, thus could be a promising nanofabric material in developing optoelectronic devices that are responsive to the gas.
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  • Date Issued: 2012

Photophysical characterization of dysprosium, erbium and lutetium phthalocyanines tetrasubstituted with phenoxy groups at non-peripheral positions

  • Authors: Zugle, Ruphino , Litwinski, Christian , Nyokong, Tebello
  • Date: 2011
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/247561 , vital:51595 , xlink:href="https://doi.org/10.1016/j.poly.2011.03.030"
  • Description: Dysprosium bis-phthalocyanine and monomeric phthalocyanines of erbium and lutetium with non-peripheral phenoxy substituents have been synthesized using two different preparative routes. Photophysical studies on these phthalocyanines revealed that the triplet states of dysprosium and erbium are not populated while the monomeric phthalocyanine complex of lutetium is populated with a quantum yield of 0.83 and a lifetime of 25 μs in DMSO. It was further found that the phthalocyanine complex of lutetium was capable of photochemical generation of singlet state molecular oxygen with yield of 0.71 in THF, thus a promising photosensitizer. However, the three phthalocyanine molecules have very low fluorescence quantum yields of less than 0.01.
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  • Date Issued: 2011

Physico-chemical properties of lutetium phthalocyanine complexes in solution and in solid polystyrene polymer fibers and their application in photoconversion of 4-nitrophenol

  • Authors: Zugle, Ruphino , Nyokong, Tebello
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/243520 , vital:51160 , xlink:href="https://doi.org/10.1016/j.molcata.2012.02.010"
  • Description: The photophysical and photochemical behavior of two phthalocyanine complexes of lutetium peripherally substituted with tetraphenoxy and tetra-2-pyridiloxy groups were studied in solution and when dispersed in polystyrene polymer fiber. The phthalocyanines were found not to fluoresce significantly in solution and not at all within the fiber matrix as compared with standard unsubstituted zinc phthalocyanine. They showed very promising photoactivity in solution with high singlet oxygen quantum yields. Their photoactivity within the polymer fiber matrix was also demonstrated with the photoconversion of 4-nitrophenol, a water pollutant. The photodegradation process with both phthalocyanines follows first order kinetics similar to that observed for the zinc phthalocyanine and the photo-products were found to be hydroquinone, benzoquinone and 4-nitrocatechol.
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  • Date Issued: 2012

Photooxidation of 4-chlorophenol sensitized by lutetium tetraphenoxy phthalocyanine anchored on electrospun polystyrene polymer fiber

  • Authors: Zugle, Ruphino , Antunes, Edith M , Khene, Samson M , Nyokong, Tebello
  • Date: 2012
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/245787 , vital:51405 , xlink:href="https://doi.org/10.1016/j.poly.2011.11.005"
  • Description: An electrospun polystyrene (PS) fiber incorporating tetraphenoxy phthalocyanine complex of lutetium (LuTPPc/PS) as a photosensitizer was applied for the degradation of 4-chlorophenol in aqueous solution in the presence of visible light. The photocatalytic activity of the LuTPPc in the fiber was compared to that of zinc phthalocyanine (ZnPc) incorporated into the PS fiber, and the former showed higher activity. UV–Vis spectral changes of sample solutions indicated transformation of the analyte with first order kinetics and half-lives that are within one and half hours for LuTPPc/PS. Products identified from the spectral changes and gas chromatography were benzoquinone, hydroquinone and 4,4′-dihydroxydiphenol suggesting that the photodegradation of 4-chlorophenol was through both Types I and II mechanisms.
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  • Date Issued: 2012

Photophysical and photochemical behavior of electrospun fibers of a polyurethane polymer chemically linked to lutetium carboxyphenoxy phthalocyanine

  • Authors: Zugle, Ruhpino , Litwinski, Christian , Torto, Nelson , Nyokong, Tebello
  • Date: 2011
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/248428 , vital:51685 , xlink:href="https://doi.org/10.1039/C1NJ20126C"
  • Description: A phthalocyanine complex of lutetium substituted with four peripherally substituted 4-carboxyphenoxy groups was synthesized using cyclotetramerisation reaction. Its structure was elucidated using conventional spectroscopic methods and elemental analysis. The spectral behavior of the complex was studied in DMF solution and in a solid polyurethane fiber matrix. The UV-Visible spectrum showed a red shift in its Q-band maximum absorption within the fiber as compared to that in solution. The triplet quantum yield in DMF was determined to be 0.51 with a lifetime of 2.7 μs and a singlet oxygen quantum yield of 0.33 with a lifetime of 19.85 μs in the same solvent. The functionalized phthalocyanine fiber could be a promising fabric material for applications such as self-disinfecting in wound dressing. A method based on the conversion of ADMA was used to estimate the singlet oxygen quantum yield of the Pc in the hybrid fiber. An estimated singlet oxygen quantum yield value of 0.11 in aqueous medium was obtained. The fluorescence quantum yield of the Pc was found to be 0.01 with a lifetime of 3.20 ns in DMF.
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  • Date Issued: 2011

The stories African lawyers could tell when analysing legal issues: Lessons for social sciences teachers

  • Authors: Zongwe, Dunia P
  • Date: 2021
  • Subjects: Decolonization Storytelling Law--Study and teaching Article
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/11260/6989 , vital:52634 , xlink:href="https://doi.org/10.4102/hts.v77i2.6828"
  • Description: Activists and academics have clamoured for the decolonisation of knowledge, including law. But, unfortunately hardly anyone has put forth strategies for how faculties should decolonise the law. A number of jurists have underscored the necessity to draw on customary laws and traditional values. Still, the #RhodesMustFall movement has, for the most part, been loud on the outcomes, but quiet on the methodologies. Joining the conversation on the decolonisation of epistemologies, this article contributes to the ongoing efforts to sanitise the law by proposing to revive African oral storytelling cultures as a way to analyse the questions of law facing society. To live up to this task, this article adopts decolonial theory and, through stylised examples, illustrates how lawyers and social scientists in Africa can utilise storytelling to contextualise, (de)construct, and comprehend those questions. This article assumes that lawyers can use African storytelling alongside the prevailing doctrinal method. That method, relaying the coloniality of law and captured by the acronym IRAC (issue(s), rules, application, and conclusion), trains students to approach conflict in society through a highly abstract and decontextualised problem-solving model. Lately, some (Western) social scientists have (re)discovered the practicality of storytelling in presenting analysis and research. However, in African oral traditions, stories worked differently from the manner in which those scientists employ them. African storytelling played a leading role, not only in conveying collective wisdom and social memory from one generation to the next, but also as a medium through which communities transmit the values that hold them together. Contribution: This article adds to the scholarship on storytelling and narratology by showing how educators can utilise stories to analyse legal questions. That rich scholarship in the humanities and the social sciences has so far not taken seriously the possibility of using stories to analyse research problems. Instead, scholars focus on storytelling mainly as a way of presenting science, not as an analytical tool. This article bridges that gap and demonstrates the analytical value of storytelling. Keywords: decolonisation of knowledge; decolonial theory; storytelling; Africa; analysis; epistemology; legal education; oral tradition.
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  • Date Issued: 2021

The stories African lawyers could tell when analysing legal issues: Lessons for social sciences teachers

  • Authors: Zongwe, Dunia P
  • Date: 2021
  • Subjects: Decolonization Storytelling Law--Study and teaching Article
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/11260/7215 , vital:53086 , xlink:href="https://doi.org/10.4102/hts.v77i2.6828"
  • Description: Activists and academics have clamoured for the decolonisation of knowledge, including law. But, unfortunately hardly anyone has put forth strategies for how faculties should decolonise the law. A number of jurists have underscored the necessity to draw on customary laws and traditional values. Still, the #RhodesMustFall movement has, for the most part, been loud on the outcomes, but quiet on the methodologies. Joining the conversation on the decolonisation of epistemologies, this article contributes to the ongoing efforts to sanitise the law by proposing to revive African oral storytelling cultures as a way to analyse the questions of law facing society. To live up to this task, this article adopts decolonial theory and, through stylised examples, illustrates how lawyers and social scientists in Africa can utilise storytelling to contextualise, (de)construct, and comprehend those questions. This article assumes that lawyers can use African storytelling alongside the prevailing doctrinal method. That method, relaying the coloniality of law and captured by the acronym IRAC (issue(s), rules, application, and conclusion), trains students to approach conflict in society through a highly abstract and decontextualised problem-solving model. Lately, some (Western) social scientists have (re)discovered the practicality of storytelling in presenting analysis and research. However, in African oral traditions, stories worked differently from the manner in which those scientists employ them. African storytelling played a leading role, not only in conveying collective wisdom and social memory from one generation to the next, but also as a medium through which communities transmit the values that hold them together. Contribution: This article adds to the scholarship on storytelling and narratology by showing how educators can utilise stories to analyse legal questions. That rich scholarship in the humanities and the social sciences has so far not taken seriously the possibility of using stories to analyse research problems. Instead, scholars focus on storytelling mainly as a way of presenting science, not as an analytical tool. This article bridges that gap and demonstrates the analytical value of storytelling. Keywords: decolonisation of knowledge; decolonial theory; storytelling; Africa; analysis; epistemology; legal education; oral tradition.
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  • Date Issued: 2021

The stories African lawyers could tell when analysing legal issues: Lessons for social sciences teachers

  • Authors: Zongwe, Dunia P
  • Date: 2021
  • Subjects: Africa storytelling
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/11260/6229 , vital:45341 , https://doi.org/10.4102/hts.v77i2.6828
  • Description: Activists and academics have clamoured for the decolonisation of knowledge, including law. But, unfortunately hardly anyone has put forth strategies for how faculties should decolonise the law. A number of jurists have underscored the necessity to draw on customary laws and traditional values. Still, the #RhodesMustFall movement has, for the most part, been loud on the outcomes, but quiet on the methodologies. Joining the conversation on the decolonisation of epistemologies, this article contributes to the ongoing efforts to sanitise the law by proposing to revive African oral storytelling cultures as a way to analyse the questions of law facing society. To live up to this task, this article adopts decolonial theory and, through stylised examples, illustrates how lawyers and social scientists in Africa can utilise storytelling to contextualise, (de)construct, and comprehend those questions. This article assumes that lawyers can use African storytelling alongside the prevailing doctrinal method. That method, relaying the coloniality of law and captured by the acronym IRAC (issue(s), rules, application, and conclusion), trains students to approach conflict in society through a highly abstract and decontextualised problem-solving model. Lately, some (Western) social scientists have (re)discovered the practicality of storytelling in presenting analysis and research. However, in African oral traditions, stories worked differently from the manner in which those scientists employ them. African storytelling played a leading role, not only in conveying collective wisdom and social memory from one generation to the next, but also as a medium through which communities transmit the values that hold them together. Contribution: This article adds to the scholarship on storytelling and narratology by showing how educators can utilise stories to analyse legal questions. That rich scholarship in the humanities and the social sciences has so far not taken seriously the possibility of using stories to analyse research problems. Instead, scholars focus on storytelling mainly as a way of presenting science, not as an analytical tool. This article bridges that gap and demonstrates the analytical value of storytelling.
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  • Date Issued: 2021

T Kondo (Ed) law and investment in Africa: the fovernance of foreign direct investment in Zimbabwe

  • Authors: Zongwe, Dunia P
  • Date: 2021
  • Subjects: Investments, Foreign -- Africa, Sub-Saharan , Zimbabwe -- Economic conditions , Corporate governance
  • Language: English
  • Type: text , review , article
  • Identifier: http://hdl.handle.net/11260/6387 , vital:45443 , xlink:href="http://dx.doi.org/10.17159/2077-4907/2021/ldd.v25.16 "
  • Description: Tinashe Kondo’s book, Law and investment in Africa, narrates the efforts of a country to regain the trust [and the love] of foreign investors after several decades of argument and hostility. Encapsulated in the “Zimbabwe is open for business” slogan, these efforts show “how a country can move to regain credibility and commit to global rules despite its recent history”. This review of Kondo’s book concerns the manner in which readers can take advantage of this immensely useful publication. Particularly, this review looks into the book in order to advise law academics on possible strategies to integrate the book into their curricula in Zimbabwe and elsewhere on the continent.
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  • Date Issued: 2021

Specialty Grand Challenges in Urban Agriculture: Ecological and Social Approaches to Sustainability Transformations

  • Authors: Zimmerer, Karl S , Bell, Martha G , Chirisa, Innocent , Duvall, Chris S , Egerer, Monika , Hung, Po-Yi , Lerner, Amy M , Shackleton, Charlie M , Ward, James David , Yacamán Ochoa, Carolina
  • Date: 2021
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/175779 , vital:42623 , https://doi.org/10.3389/fsufs.2021.668561
  • Description: This synopsis of the Grand Challenges of Urban Agriculture (UA) is framed by the urgent need to understand and strengthen the expanding yet highly diverse roles of UA amid rapid global urbanization, failures of predominant food systems, and crises in systems of physical and mental health. More than half of humanity lives in cities today and by 2030 this is projected to grow to 60.4 percent, ~5 billion people (UN Habitat, 2020). More than 90 percent of urban demographic increase is anticipated to take place in the developing world.
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  • Date Issued: 2021

Grand challenges in urban agriculture: ecological and social approaches to transformative sustainability

  • Authors: Zimmerer, Karl S , Bell, Martha G , Chirisa, Innocent , Duvall, Chris S , Egerer, Monika , Hung, Po-Yi , Lerner, Amy M , Shackleton, Charlie M , Ward, James D , Ochoa, Carolina Y
  • Date: 2021
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/402287 , vital:69838 , xlink:href="https://doi.org/10.3389/fsufs.2021.668561"
  • Description: This synopsis of the Grand Challenges of Urban Agriculture (UA) is framed by the urgent need to understand and strengthen the expanding yet highly diverse roles of UA amid rapid global urbanization, failures of predominant food systems, and crises in systems of physical and mental health. More than half of humanity lives in cities today and by 2030 this is projected to grow to 60.4 percent, ∼5 billion people (UN Habitat, 2020). More than 90 percent of urban demographic increase is anticipated to take place in the developing world. Ecological and social dimensions of UA are situated in these expanding spaces of cities, towns, and villages (along with their urban fringe or peri-urban areas), and among their diverse populations. UA is further situated in the powerful, far-reaching influences of urbanization processes that occur within and beyond these spaces. UA is thus integral to the prospect of Urban Sustainability as SDG 11 (“Make cities and human settlements inclusive, safe, resilient and sustainable”) of the U.N.’s 2030 Agenda for Sustainable Development.
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  • Date Issued: 2021

Agathis bishopi, a larval parasitoid of false codling moth Thaumatotibia leucotreta: laboratory rearing and effect of adult food on parasitism and longevity

  • Authors: Zimba, Kennedy J , Moore, Sean D , Heshula, LU , 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

Host searching and oviposition behaviour of Agathis bishopi (Hymenoptera: Braconidae), a larval parasitoid of false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae): a potential proxy indicator for fruit infestation

  • Authors: Zimba, Kennedy J , Heshula, LU , Moore, Sean D , Hill, Martin P
  • Date: 2015
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/407019 , vital:70330 , xlink:href="https://hdl.handle.net/10520/EJC195073"
  • Description: Agathis bishopi (Nixon) (Hymenoptera: Braconidae)is an arrhenotokous larval endoparasitoid of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (Gendall 2007; Hofmeyr et al. 2015) commonly known as false codling moth (FCM), a major pest of citrus in South Africa (Moore et al. 2004; Malan et al. 2011). Under field conditions, A. bishopi was identified attacking more than 34% of FCM larvae in fruit, showing good biocontrol potential (Gendall 2007). Preference by A. bishopi for parasitising the early instars of its concealed host suggests that the parasitoid has strong natural host location ability (Sishuba 2003; Gendall 2007).
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  • Date Issued: 2015

Agathis bishopi (Hymenoptera: Braconidae) as a potential tool for detecting oranges infested with Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

  • 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

A missing link in the estuarine nitrogen cycle?: coupled nitrification-denitrification mediated by suspended particulate matter

  • Authors: Zhu, Weijing , Wang, Cheng , Hill, Jaclyn M , He, Yangyang , Tao, Bangyi , Mao, Zhihua , Wu, Weixiang
  • Date: 2018
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/68368 , vital:29244 , https://0-doi.org.wam.seals.ac.za/10.1038/s41598-018-20688-4
  • Description: In estuarine and coastal ecosystems, the majority of previous studies have considered coupled nitrification-denitrification (CND) processes to be exclusively sediment based, with little focus onsuspended particulate matter (SPM) in the water column. Here, we present evidence of CND processes in the water column of Hangzhou Bay, one of the largest macrotidal embayments in the world.
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  • Date Issued: 2018

13C pulse-chase labeling comparative assessment of the active methanogenic archaeal community composition in the transgenic and nontransgenic parental rice rhizospheres

  • Authors: Zhu, Weijing , Lu, Haohao , Hill, Jaclyn M , Wang, Hailong , Wu, Weixiang
  • Date: 2013
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/122993 , vital:35389 , https://doi.org/10.1111/1574-6941.12261
  • Description: Rhabdosargus holubi (Steindachner, 1881) is a small (maximum size = 450 mm total length; Heemstra and Heemstra 2004) sparid that is distributed along the south-east coast of Africa from St Helena Bay, South Africa, to Maputo, Mozambique (Götz and Cowley 2013). Spawning occurs in the nearshore marine environment primarily during winter, specifically May–August in KwaZulu-Natal (KZN) (Wallace 1975) and July–February in the South-Eastern Cape (Whitfield 1998). Individuals reach 50% sexual maturity at approximately 150 mm standard length (SL) in the Eastern Cape (Whitfield 1998). The early life stages are transported by the south-westward-flowing Agulhas Current, and recruit as post-flexion larvae and early juveniles into estuaries during late winter and early summer (Blaber 1974). The warm temperatures and high nutrient levels in estuaries favour fast growth (Blaber 1973a), and fish spend their first year of life in these environments, migrating back out to sea after reaching approximately 120 mm SL. Some individuals remain trapped in closed estuaries, where they may reach sizes greater than 200 mm SL (James et al. 2007a). Rhabdosargus holubi is the dominant estuarine-dependent marine teleost species recorded in permanently open and temporarily open/closed estuaries in the warm-temperate region, which spans the south, south-east and east coast of South Africa (Harrison 2005). The species is also an important component of the linefishery in many SouthAfrican estuaries (10–15.6% by number) (Pradervand and Baird 2002), particularly in Eastern Cape estuaries (Cowley et al. 2003). These figures underestimate the presence of R. holubi, as most individuals making use of estuaries are young, feeding predominately on filamentous macroalgae and diatom flora, and are generally too small to be caught with hook and line (De Wet and Marais 1990). James et al. (2007b) showed that R. holubi made up 34–92% of the annual seine-net catch in the East Kleinemonde Estuary. Rhabdosargus holubi is also important in the KZN shorebased linefishery, representing 4.6% of the total landed catch (Dunlop and Mann 2012)More and more investigations indicate that genetic modification has no significant or persistent effects on microbial community composition in the rice rhizosphere. Very few studies, however, have focused on its impact on functional microorganisms. This study completed a 13C-CO2 pulse-chase labeling experiment comparing the potential effects of cry1Ab gene transformation on 13C tissue distribution and rhizosphere methanogenic archaeal community composition with its parental rice variety (Ck) and a distant parental rice variety (Dp). Results showed that 13C partitioning in aboveground biomass (mainly in stems) and roots of Dp was significantly lower than that of Ck. However, there were no significant differences in 13C partitioning between the Bt transgenic rice line (Bt) and Ck. RNA-stable isotope probing combined with clone library analyses inferred that the group Methanosaetaceae was the predominant methanogenic Archaea in all three rice rhizospheres. The active methanogenic archaeal community in the Bt rhizosphere was dominated by Methanosarcinaceae, Methanosaetaceae, and Methanomicrobiaceae, while there were only two main methanogenic clusters (Methanosaetaceae and Methanomicrobiaceae) in the Ck and Dp rhizospheres. These results indicate that the insertion of cry1Ab gene into the rice genome has the potential to result in the modification of methanogenic community composition in its rhizosphere.
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  • Date Issued: 2013
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