A temporal dimension to the influence of pollen rewards on bee behaviour and fecundity in Aloe tenuior
- Authors: Duffy, Karl J , Johnson, Steven D , Peter, Craig I
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6561 , http://hdl.handle.net/10962/d1011735 , http://dx.doi.org/10.1371/journal.pone.0094908
- Description: The net effect of pollen production on fecundity in plants can range from negative – when self-pollen interferes with fecundity due to incompatibility mechanisms, to positive – when pollen availability is associated with increased pollinator visitation and fecundity due to its utilization as a reward. We investigated the responses of bees to pollen and nectar rewards, and the effects of these rewards on pollen deposition and fecundity in the hermaphroditic succulent shrub Aloe tenuior. Self-pollinated plants failed to set fruit, but their ovules were regularly penetrated by self-pollen tubes, which uniformly failed to develop into seeds as expected from ovarian self-incompatibility (or strong early inbreeding depression). Bees consistently foraged for pollen during the morning and early afternoon, but switched to nectar in the late afternoon. As a consequence of this differential foraging, we were able to test the relative contribution to fecundity of pollen- versus nectar-collecting flower visitors. We exposed emasculated and intact flowers in either the morning or late afternoon to foraging bees and showed that emasculation reduced pollen deposition by insects in the morning, but had little effect in the afternoon. Despite the potential for self-pollination to result in ovule discounting due to late-acting self-sterility, fecundity was severely reduced in artificially emasculated plants. Although there were temporal fluctuations in reward preference, most bee visits were for pollen rewards. Therefore the benefit of providing pollen that is accessible to bee foragers outweighs any potential costs to fitness in terms of gender interference in this species.
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Applications of lead phthalocyanines embedded in electrospun fibers for the photoinactivation of Escherichia coli in water
- Authors: Osifeko, Olawale L , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7304 , http://hdl.handle.net/10962/d1020381
- Description: Lead (II) pyridyloxyphthalocyanine (PbTpyPc) and its quaternized form (PbTepyPc) were synthesized and the photophysical behavior examined. Low fluorescence quantum yields (ΦF) of 0.01 and 0.02 were observed for PbTepyPc and PbTpyPc, respectively. The singlet oxygen quantum yields (ΦΔ) were 0.60 and 0.68, for PbTepyPc and PbTpyPc, respectively using DPBF as a quencher in DMF. Singlet oxygen production of the embedded sensitizers in electrospun fiber were quantified using ADMA and were found to be ΦΔ = 0.41 and ΦΔ = 0.21 for PbTepyPc and PbTpyPc, respectively. Photodynamic inactivation of Escherichia coli (E. coli) with the quaternized photosensitizer at 5 μM, totally inactivated the E. coli (with log CFU = 10 decrease). Only 0.4 log CFU decrease was obtained with PbTpyPc. The embedded non-quaternized photosensitizer (PbTpyPc) was less active on the gram negative bacteria but the quaternized photosensitizer (PbTepyPc) was effective towards inactivation of E. coli. , Original publication is available at http://dx.doi.org/10.1016/j.dyepig.2014.05.010
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Behavior of Palladium Nanoparticles in the Absence or Presence of Cobalt Tetraaminophthalocyanine for the Electrooxidation of Hydrazine
- Authors: Maringa, Audacity , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7305 , http://hdl.handle.net/10962/d1020382
- Description: We report on the electrodeposition of palladium nanoparticles (PdNPs) on a glassy carbon electrode (GCE) and onto a poly-CoTAPc-GCE (CoTAPc=cobalt tetraamino phthalocyanine) surface. The electrodes are denoted as PdNPs-GCE and PdNPs/poly-CoTAPc-GCE, respectively. PdNPs/poly-CoTAPc-GCE showed the best activity for the oxidation of hydrazine at the lowest potential of −0.28 V and with the highest currents. The results were further supported by electrochemical impedance spectroscopy (EIS) which showed that there was less resistance to charge transfer for PdNPs/poly-CoTAPc-GCE compared to PdNPs-GCE. The catalytic rate constant for hydrazine oxidation was 6.12×108 cm3 mol−1 s−1 using PdNPs/poly-CoTAPc-GCE. , Original publication is available at http://dx.doi.org/10.1002/elan.201400028
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Bells as memorials in South Africa to the Great (1914-18) War
- Authors: Lewis, Colin A , De Wet, Tertius , Teugels, Jet L , Van Deventer, Pieta J U
- Date: 2014
- Language: English
- Type: Article , text
- Identifier: vital:6192 , http://hdl.handle.net/10962/d1013418
- Description: The contribution of South Africa to the allied cause in the Great War, and the sacrifice of so many lives of the White and Coloured populations, is memorialised on bells of the Cape Town carillon, on ringing, and on clock and other bells. The contribution of the Black population awaits recognition. Restoration of the Cape Town carillon so that it can again be played effectively, would be a fitting memorial to those who lost their lives in the non-combative roles that were open to the majority population of South Africa. Completion of the ring at what is now Queenstown cathedral would also be a fitting tribute to the bravery and unstinting service of so many South Africans during the Great War. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
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Cracks in reproductive health rights: knowledge of abortion legislation stipulations amongst learners in Buffalo City, South Africa
- Authors: Macleod, Catriona I , Seutlwadi, Lebogang , Steele, Gary I
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6296 , http://hdl.handle.net/10962/d1014772
- Description: Background: The Choice on Termination of Pregnancy (CTOP) Act legalised abortion on request in South Africa until up to 12 weeks of gestation and thereafter under specified conditions. Within the context of liberal legislation, accurate information is a necessary (although not sufficient) requirement for women to exercise their reproductive rights. Objectives: This research investigated Grade 11 learners’ knowledge of the CTOP Act and its stipulations. Methods: Survey research was conducted with respondents drawn from a range of schools in Buffalo City, South Africa. Multi-stage sampling was used, namely stratified random sampling of schools and purposive sampling of grades used within schools. The data were collected by means of self-administered questionnaires in group situations. Results: Results indicate that knowledge of the legal status of abortion, as well as of the various stipulations of the law, was poor. Various misunderstandings were evident, including that spousal approval is required in order for married women to have an abortion. Significant differences between the knowledge of respondents at the various schools were found, with those learners attending schools formerly designated for African learners during Apartheid having the least knowledge. Conclusion: Given the multiple factors that may serve as barriers to women accessing abortion, it is imperative that at least the most fundamental aspect of reproductive rights, that is, the right to information, is not undermined.
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Crimes against nature : ecocritical discourse in South African crime fiction
- Authors: Naidu, Samantha
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:26322 , http://hdl.handle.net/10962/53754 , http://dx.doi.org/10.1080/18125441.2014.950599 , https://orcid.org/0000-0001-9456-8657
- Description: Heeding Patrick Murphy's call to critics, in his book, Ecocritical explorations in literary and cultural studies: fences, boundaries and field, to study “nature-oriented mystery novels … in order to understand the degree to which environmental consciousness and nature awareness has permeated popular and commercial fiction” (2009: 143), this article examines how highly successful author, Deon Meyer, has employed crime fiction to popularize ecological issues and debates in South Africa. In this article, Meyer's first “nature-oriented” novel, the crime thriller, Blood safari (2009), is analysed. The main question asked is whether South African crime fiction deploys ecocritical discourse for mercenary reasons or whether its engagement with environmental issues constitutes a bona fide sub-category of ecocritical literature. The same rationale – understanding how “environmental consciousness and nature awareness” manifest in one of the most popular and commercially viable genres of fiction in South Africa today – informs the broader study from which this article is drawn. Some of the findings of this study, which includes a reading of Meyer's second “nature-oriented” novel, Trackers (2011), Jane Taylor's Of wild dogs, Margaret von Klemperer's Just a dead man, and Ingrid Winterbach's literary detective novel, The book of happenstance, are referred to briefly. To conclude, the contribution of “nature-oriented” crime fiction to a “localised ecocriticism” is assessed
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Effects of pyrene on the photophysical and two-photon absorption-based nonlinear optical properties of indium(III) phthalocyanines
- Authors: Sanusi, Kayode , Nyokong, Tebello
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:7314 , http://hdl.handle.net/10962/d1020540
- Description: Photophysical and two-photon-dependent nonlinear absorption properties of two chloroindium(III) phthalocyanines bearing pyrene units have been investigated. The tetra- (3) and the tri- (4) pyrene-substituted phthalocyanines exhibit strong triplet absorption with high triplet yields () of 0.79 and 0.83, respectively. The measured nonlinear optical data, such as the two photon absorption cross-sections, the third- and second-order nonlinearities were found to be comparable with those of literature, thus, making the compounds promising candidates for a broad range of nonlinear optical applications. , Original publication is available at http://dx.doi.org/10.1080/00958972.2014.959509
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IziNambuzane: isiZulu names for insects
- Authors: Cockburn, Jessica J , Khumalo-Seegelken, B , Villet, Martin H
- Date: 2014
- Subjects: Insects -- South Africa -- KwaZulu-Natal -- Nomenclature , Zulu language -- Revival , Language policy -- South Africa -- KwaZulu-Natal , Native language and education -- Research -- South Africa -- KwaZulu-Natal , Ethnoentomology
- Language: English
- Type: Article
- Identifier: vital:6972 , http://hdl.handle.net/10962/d1014581
- Description: We provide a tool for communicating about insects in isiZulu to facilitate research and knowledge sharing in the fields of indigenous knowledge, cultural entomology, environmental education and community extensioninvolving isiZulu speakers. A total of 213 different names for 64 insect specimens were encountered among a sample of 67 respondents in 11 communities distributed across the province of KwaZulu-Natal, South Africa. This list includes 93 names that can be considered core isiZulu vocabulary and which are widely used to identify insects that are agriculturally, medically, domestically, culturally or ecologically common or significant. Substantial variation was found regarding the names for particular insects, especially between regions, suggesting dialectal differences between isiZulu speakers. Grammatical and social variation in names was also recorded. This study highlights interdisciplinary teamwork in the field of indigenous knowledge research and the influences affecting the standardisation of South African languages for technical and scientific work.
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New possibilities for research on reef fish across the continental shelf of South Africa
- Authors: Bernard, Anthony T F , Gotz, A , Parker, Daniel M , Heyns, Elodie R , Halse, Sarah J , Riddin, N A , Smith, M K S , Paterson, Angus W , Winker, A Henning , Fullwood, L , Langlois, T J , Harvey, E S
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6971 , http://hdl.handle.net/10962/d1014566
- Description: [From introduction] Subtidal research presents numerous challenges that restrict the ability to answer fundamental ecological questions related to reef systems. These challenges are closely associated with traditional monitoring methods and include depth restrictions (e.g. safe diving depths for underwater visual census), habitat destruction (e.g. trawling), mortality of target species (e.g. controlled angling and fish traps), and high operating costs (e.g. remotely operated vehicles and large research vessels. Whereas many of these challenges do not apply or are avoidable in the shallow subtidal environment, the difficulties grow as one attempts to sample deeper benthic habitats. This situation has resulted in a paucity of knowledge on the structure and ecology of deep water reef habitats around the coast of South Africa and in most marine areas around the world. Furthermore, the inability to effectively survey deep water benthic environments has limited the capacity of researchers to investigate connectivity between shallow and deep water habitats in a standardised and comparable fashion.
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Sailing between Scylla and Charybdis: Mayelane v Ngwenyama
- Authors: Kruuse, Helen
- Date: 2014
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54118 , vital:26392 , https://www.ajol.info/index.php/pelj/article/view/112096
- Description: Mayelane v Ngwenyama 2013 4 SA 415 (CC) is arguably the most important judgment concerning the recognition of customary marriages in recent times. This article attempts to unpack some of the many issues that arise from the case, namely: (a) the practical difficulties associated with ascertaining living customary law and the problems of identifying legal versus social norms; (b) the meaning of consent as a requirement of a customary marriage; (c) the implications of the case for equality between multiple wives in a customary marriage, and as between wives across customary marriages of different cultural traditions; and (e) the implications of the case for equality considerations more broadly. While the authors sympathise with the court in respect of the complex decision before it, it questions the Court's method and result, specifically for the equality rights of a second (or further) "wife" in a Vatsonga customary marriage. The authors suggest that the issues should be put to democratic deliberation by the legislative arm, rather than leaving courts in the unenviable position of having to decide these matters.
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The relationship between double taxation agreements and the provisions of the South African Income Tax Act
- Authors: Stack, Elizabeth M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: Article
- Identifier: vital:21102 , http://hdl.handle.net/10962/6384 , http://journals.co.za/content/jefs/7/2/EJC157823
- Description: This article investigates the legal status of Double Taxation Agreements, and the relationship between Double Taxation Agreements, which are concluded in terms of section 108 of the Income Tax Act, and the provisions of the Income Tax Act (taking into account the provisions of the Constitution, and the national and international rules for the interpretation of statutes). An important conclusion reached was that as the Vienna Convention on the Law of Treaties represents customary international law and as such forms part of South African law, the principles contained in the treaty should be taken into account when interpreting South African legislation (including Double Taxation Agreements).The final conclusion of the research was that Double Taxation Agreements have a dual nature – forming part of domestic legislation and being classified as international agreements. The provisions of the Double Taxation Agreement should be taken as overriding any conflicting legislation in the Income Tax Act.
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The struggle for authority in George McCall Theal's Kaffir Folklore
- Authors: Naidu, Samantha
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:26362 , http://hdl.handle.net/10962/53942 , https://www.upjournals.co.za/index.php/SAJFS/article/view/1674 , https://orcid.org/0000-0001-9456-8657
- Description: This article focuses specifically on George McCall Theal’s collection of folktale texts, Kaffir Folklore (1882), as an example of an early South African ethnographic publication, and argues that the folktale transcriptions contained therein, although a part of Theal’s general colonialist project, are hybrid, containing the voices of both coloniser and colonised. The key argument is that the presence of the African voices in this text reveals simultaneously that Theal’s editorial aspirations were never absolutely imposed, and that agency and influence (albeit limited) of the colonised Xhosa co-authors were present. The article offers an analysis of the paratext (the preface, the introduction and the explanatory notes) of Kaffir Folkore, rather than a close reading of the tales themselves. To facilitate an understanding of Theal’s editorial practice, Kaffir Folkore is compared to Harold Scheub’s The Xhosa Ntsomi (1975). More generally, drawing on postcolonial folklore and book-history scholarship, the article explores how folklore texts of the colonial era, although contributing to the establishment of a literary and cultural orthodoxy in modern South Africa, constitute a telling hybrid genre, which invites a re-evaluation of colonial relations, and of individual texts themselves. In short, these texts synthesise different literary traditions (European and African), different mediums (the oral and the written), different disciplinary approaches (ethnography, folklore, literature), and most significantly, the voices of different subjects. Kaffir Folklore (1882) epitomises this synthesis
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Tufa stromatolite ecosystems on the South African south coast
- Authors: Perissinotto, Renzo , Bornman, Tommy G , Steyn, Paul-Pierre , Miranda, Nelson A F , Dorrington, Rosemary A , Matcher, Gwynneth F , Strydom, Nadine A , Peer, Nasreen
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6490 , http://hdl.handle.net/10962/d1014585 , http://dx.doi.org/10.1590/sajs.2014/20140011
- Description: Following the first description of living marine stromatolites along the South African east coast, new investigations along the south coast have revealed the occurrence of extensive fields of actively calcifying stromatolites. These stromatolites have been recorded at regular distances along a 200-km stretch of coastline, from Cape Recife in the east to the Storms River mouth in the west, with the highest density found between Schoenmakerskop and the Maitland River mouth. All active stromatolites are associated with freshwater seepage streams flowing from the dune cordon, which form rimstone dams and other accretions capable of retaining water in the supratidal platform. Resulting pools can reach a maximum depth of about 1 m and constitute a unique ecosystem in which freshwater and marine organisms alternate their dominance in response to vertical mixing and the balance between freshwater versus marine inflow. Although the factors controlling stromatolite growth are yet to be determined, nitrogen appears to be supplied mainly via the dune seeps. The epibenthic algal community within stromatolite pools is generally co-dominated by cyanobacteria and chlorophytes, with minimal diatom contribution.
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Writing the violated body : representations of violence against women in Margie Orford’s crime thriller novels
- Authors: Naidu, Samantha
- Date: 2014
- Language: English
- Type: Article , text
- Identifier: vital:26361 , http://hdl.handle.net/10962/53932 , http://dx.doi.org/10.1080/18125441.2014.904396 , https://orcid.org/0000-0001-9456-8657
- Description: Using the late twentieth-century French feminist notions of écriture féminine and the abject as a starting point, this article considers the various pitfalls, effects and ethical ramifications of representations of violence against the female body in South African crime fiction. How do authors reconcile the entertainment value of such representations with their aims to perform social analysis? This article attempts to answer this question by first describing how violence targeted at the female body is graphically portrayed, and, second, by assessing the effects of these visceral descriptions. Margie Orford’s novels, in particular, the first in the Clare Hart series, Like clockwork (2006), which foregrounds human trafficking, prostitution and gender-based violence, will be examined. In Orford’s Clare Hart series, the female detective figure, the various plots to do with assault, abduction, rape and murder, and the explicit imagery that descriptively conveys such crimes, are narrative techniques employed by Orford to address this scourge, and the patriarchy and sexism of contemporary South African society in general. The article ends by assessing whether a bona fide feminist subgenre of South African crime fiction is being inscribed by Orford
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