Ericoid fungal inoculation of blueberry under commercial production in South Africa
- Authors: Bizabani, Christine , Fontenla, Sonia , Dames, Joanna F
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448610 , vital:74746 , https://doi.org/10.1016/j.scienta.2016.06.029
- Description: Ericoid mycorrhizal (ERM) fungi are known to enhance growth of plants belonging to the Ericaceae family. However, the outcomes of root-fungal associations in this family are influenced by several factors such as soil nutrient status, climatic conditions, host variety and fungal partner. The aim of this study was (i) to determine whether symbiotic fungal structures form in roots of Misty (Vaccinium corymbosum) and Brightwell (V. ashei) blueberry varieties, following inoculation with Leohumicola, Oidiodendron maius and Meliniomyces fungal species, and (ii) evaluate inoculation effects on the growth of blueberry varieties. The study was conducted for 60 weeks under commercial production conditions at Amathole Berries, Sutterheim, South Africa. All three fungi were isolated from Erica plants growing naturally in Albany Centre of Endemism of South Africa. All ERM formed mycorrhizal structures characteristic of typical ericoid colonisation in the roots of both Misty and Brightwell. However, percentage colonisation was low. The highest colonisation percentage, 20.4%, was observed in Misty inoculated with Oidiodendron maius. Colonisation was significantly different compared to un-inoculated controls in the Misty variety. In both varieties inoculated with either Leohumicola or Meliniomyces did not improve (p > 0.05) shoot growth and biomass. All fungal species improved root biomass in Misty but not in Brightwell. This indicates that ERM inoculation may potentially benefit plant of Misty and that responses to ERM inoculation vary between blueberry varieties.
- Full Text:
- Date Issued: 2016
Evaluating the multi-threading countermeasure
- Authors: Frieslaar, Ibrahim , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428352 , vital:72505 , https://researchspace.csir.co.za/dspace/bitstream/handle/10204/9041/Frieslaar_2016.pdf?sequence=1andisAllowed=y
- Description: This research investigates the resistance of the multi-threaded coun-termeasure to side channel analysis (SCA) attacks. The multi-threaded countermeasure is attacked using the Correlation Power Analysis (CPA) and template attacks. Additionally, it is compared to the existing hiding countermeasure. Furthermore, additional signal processing techniques are used to increase the attack success ratio. It is demon-strated that the multi-threaded countermeasure is able to outperform the existing countermeasures by withstanding the CPA and template at-tacks. Furthermore, the multi-threaded countermeasure is unaffected by the elastic alignment and filtering techniques as opposed to the existing countermeasures. The research concludes that the multithreaded coun-termeasure is indeed a secure implementation to mitigate SCA attacks.
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- Date Issued: 2016
Expanding reproductive justice through a supportability reparative justice framework: the case of abortion in South Africa
- Authors: Macleod, Catriona I
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/443680 , vital:74143 , xlink:href="https://doi.org/10.1080/13691058.2018.1447687"
- Description: Theoretical refinement of the concept of reproductive justice has been called for. In this paper, I propose the use of a supportability reparative justice approach. Drawing on intra-categorical intersectionality, the supportability aspect starts from the event of a pregnancy to unravel the interwoven embodied and social realities implicated in women experiencing pregnancy as personally supportable/unsupportable, and socially supported/unsupported. The reparative justice aspect highlights the need for social repair in the case of unsupportable pregnancies and relies on Ernesto Verdeja’s critical theory of reparative justice in which he outlines four reparative dimensions. Using abortion within the South African context, I show how this framework may be put to use: (1) the facilitation of autonomous decision-making (individual material dimension) requires understanding women within context, and less emphasis on individual-driven ‘choice’; (2) the provision of legal, safe state-sponsored healthcare resources (collective material dimension) demands political will and abortion service provision to be regarded as a moral as well as a healthcare priority; (3) overcoming stigma and the spoiled identities (collective symbolic dimension) requires significant feminist action to deconstruct negative discourses and to foreground positive narratives; and (4) understanding individual lived experiences (individual symbolic dimension) means deep listening within the social dynamics of particular contexts.
- Full Text:
- Date Issued: 2016
Fat in a time of slim: the reinscription of race in the framing of fat desirability in post-apartheid South Africa
- Authors: Vincent, Louise
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141591 , vital:37988 , DOI: 10.1177/1363460716640730
- Description: This article critically examines the way in which the reported sexual desire of black African men for fat women is contained and managed in South African media representations of fat. While sexual desire for fat women represents a potential challenge to the dominant framing of fat as diseased/dysfunctional/disgusting, the article shows how the reduction of this desire to one of two (racialized) ‘explanations’ – either evidence of racial primitivism or a (black male) strategy to avoid infection with HIV – emasculates the potentially powerful oppositional framing of fat as sexy. It is a mark of the dominant frame’s influence that it is capable of co-opting oppositional frames and recasting them in its own image. From the point of view of critiques of the fat-as-disease orthodoxy, the claim to the existence of an alternative norm of fat as sexually desirable in ‘black culture’ emerges as a problematic oppositional frame – saturated with raced assumptions in the way in which it is reported. The counter framing of the (black) fat body as sexually desirable is given column space to be derided and dismissed as an instance of deviant black sexuality, as a mistaken belief in need of ‘correction’, or it is subsumed under a medicalized frame as a strategy for the avoidance of disease rather than an expression of genuine sexual desire.
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- Date Issued: 2016
Festival fringe production and the long tail
- Authors: Snowball, Jeanette D
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68855 , vital:29332 , http://www.econrsa.org/node/1170
- Description: Publisher version , In the past 15 years, there has been a worldwide proliferation of arts festivals, including so-called "fringe" festivals, which encouraged more experimental and avant-garde productions. While fringe festival productions had the potential to generate significant income for producers, their aims were primarily related to artistic innovation and it is well known that putting on a fringe show is highly unlikely to provide financial gain for most producers. This is what is referred to in statistics and marketing as a "long tail" distribution, in which a minority of producers in a particular market earn the vast majority of industry income. However, for individual producers of live theatre, such a distribution represents high risks and potentially large financial losses. This article uses producer data from two different fringe festivals in South Africa to explore determinants of ticket sales and box-office income. Included in the analysis is a consideration of the impact of genre and pricing strategies on the probability (Logit model) of shows being in the top 10%, 30% and 50% of best-selling and earning productions. Results support the long tail hypothesis.
- Full Text:
- Date Issued: 2016
Fluorescence behavior of nanoconjugates of graphene quantum dots and zinc phthalocyanines
- Authors: Achadu, Ojodomo John , Uddin, Imran , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188777 , vital:44784 , xlink:href="https://doi.org/10.1016/j.jphotochem.2015.11.006"
- Description: Graphene quantum dots (GQDs) and zinc phthalocyanines interactions in different modes (covalent and non-covalent) are reported in this study. GQDs were covalently attached to the following complexes: zinc tetraamino phthalocyanine (ZnTAPc) via amide coupling, zinc tetracarboxyphenoxy Pc (ZnTCPPc) (π–π interaction) and cationic zinc tetrapyridiloxy Pc (ZnTmPyPc) (ionic interaction). GQDs fluorescence was quenched in the presence of the ZnPc derivatives. The nanoensembles of GQDs–ZnPcs showed stimulated emissions of the ZnPcs. The suggested quenching mechanism is through Förster resonance energy transfer (FRET). These novel nanoensembles hold promise for various optical and luminescence based applications.
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- Date Issued: 2016
Fluorescence properties of alloyed ZnSeS quantum dots overcoated with ZnTe and ZnTe/ZnS shells
- Authors: Adegoke, Oluwasesan , Mashazi, Philani N , Nyokong, Tebello , Forbes, Patricia B C
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240754 , vital:50868 , xlink:href="https://doi.org/10.1016/j.optmat.2016.02.024"
- Description: Fluorescent alloyed ternary ZnSeS quantum dots (QDs) have been synthesized via the pyrolysis of organometallic precursors. The effects of passivation of ZnTe and ZnTe/ZnS shells on the optical properties of the ternary alloyed ZnSeS core have been studied. A ligand exchange reaction using L-cysteine as a capping ligand was used to obtain water-soluble nanocrystals. The nanocrystals were each characterized by UV/vis absorption and fluorescence spectroscopy, transmission electron microscopy, X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The photoluminescence (PL) quantum yield (QY) of alloyed ZnSeS QDs was 14% and this value increased to 27% when ZnTe was overcoated around the surface but further coating with a ZnS shell decreased the PL QY slightly to 24%. This implies that ZnTe shell suppressed non-radiative recombination exciton states in the alloyed core while further layering with a ZnS shell offered no further improvement in suppressing the defect states. XPS analysis confirmed the presence of the first shell layering but showed a weakened intensity signal of S (2p) and Se (3d) for the ZnSeS/ZnTe/ZnS QDs. Our work demonstrates for the first time that shell passivation of alloyed Zn-based QDs can offer improved optical properties. We hope the optical information presented in this work will be useful in the selection of alloyed Zn-based QDs appropriate for the intended application.
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- Date Issued: 2016
Focus on 'the family'?: how South African family policy could fail us
- Authors: Morison, Tracy , Lynch, Ingrid , Macleod, Catriona I
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446244 , vital:74484 , xlink:href="https://hsrc.ac.za/uploads/pageContent/7505/HSRC%20POLICY%20BRIEF%2011%20-%20MORISON%20Family%20policy_PRESS%20(2).pdf"
- Description: In the past decade South African policymakers have increasingly focused on families as sites of state intervention. To date, several family policies have been developed to support societal well-being and cohesion. The most recent policy document is the White Paper on Families in South Africa (DSD 2012), which aims to facilitate the mainstreaming of a family perspective into all government policy-making. Family policies are intended to provide support, enhance family members’ wellbeing, strengthen family relationships, and help families address social challenges, such as economic instability. Their ultimate aim is to ensure a safe and socially cohesive society (Robila 2014). A core concern, therefore, is with promoting ‘stable, healthy families’. This concern is valid in South Africa since many families experienced a profound lack of stability under apartheid and today instability is brought about by various socio-economic changes, especially the HIV and AIDS epidemic.
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- Date Issued: 2016
From global to regional and back again: common climate stressors of marine ecosystems relevant for adaptation across five ocean warming hotspots
- Authors: Popova, Ekaterina , Yool, Andrew , Byfield, Valborg , Cochrane, Kevern , Coward, Andrew C , Salim, Shyam S , Gasalla, Maria A , Henson, S.A , Hobday, Alistair J , Pecl, Gretta T , Sauer, Warwick H H , Roberts, Michael J
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124514 , vital:35623 , https://doi.10.1111/gcb.13247
- Description: Ocean warming ‘hotspots’ are regions characterized by above-average temperature increases over recent years, for which there are significant consequences for both living marine resources and the societies that depend on them. As such, they represent early warning systems for understanding the impacts of marine climate change, and test-beds for developing adaptation options for coping with those impacts. Here, we examine five hotspots off the coasts of eastern Australia, South Africa, Madagascar, India and Brazil. These particular hotspots have underpinned a large international partnership that is working towards improving community adaptation by characterizing, assessing and projecting the likely future of coastal-marine food resources through the provision and sharing of knowledge. To inform this effort, we employ a high-resolution global ocean model forced by Representative Concentration Pathway 8.5 and simulated to year 2099. In addition to the sea surface temperature, we analyse projected stratification, nutrient supply, primary production, anthropogenic CO2-driven ocean acidification, deoxygenation and ocean circulation. Our simulation finds that the temperature-defined hotspots studied here will continue to experience warming but, with the exception of eastern Australia, may not remain the fastest warming ocean areas over the next century as the strongest warming is projected to occur in the subpolar and polar areas of the Northern Hemisphere. Additionally, we find that recent rapid change in SST is not necessarily an indicator that these areas are also hotspots of the other climatic stressors examined. However, a consistent facet of the hotspots studied here is that they are all strongly influenced by ocean circulation, which has already shown changes in the recent past and is projected to undergo further strong change into the future. In addition to the fast warming, change in local ocean circulation represents a distinct feature of present and future climate change impacting marine ecosystems in these areas.
- Full Text:
- Date Issued: 2016
Fundisa for Change teacher professional development programme
- Authors: Tshiningayamwe, Sirkka A
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432999 , vital:72922 , xlink:href="https://eeasa.org.za/wp-content/uploads/2017/05/EEASA-Bullitin-vol-43.pdf"
- Description: Environment and sustainability content has been integrated into the South African curricula documents, including the past ones. This integration was followed by initiatives which aimed at supporting teachers to implement environmental knowledge and action in the curriculum. For example, the Learning for Sustainability project was piloted in Gauteng and Mpumalanga province between the year 1997 and 2000. The project followed a three pillar approach of integrating environmental education in the curriculum: teacher development, curriculum development and materials development. As part of the project, a spiral model approach to teacher professional development was introduced.
- Full Text:
- Date Issued: 2016
Global proliferation of cephalopods
- Authors: Doubleday, Zoë A , Prowse, Thomas A A , Arkhipkin, Alexander , Pierce, Graham J , Semmens, Jayson , Steer, Michael , Leporati, Stephen C , Lourenço, Sílvia , Quetglas, Antoni , Sauer, Warwick H H , Gillanders, Bronwyn M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124560 , vital:35628 , https://doi.10.1016/j.cub.2016.04.002
- Description: Human activities have substantially changed the world’s oceans in recent decades, altering marine food webs, habitats and biogeochemical processes [1]. Cephalopods (squid, cuttlefish and octopuses) have a unique set of biological traits, including rapid growth, short lifespans and strong life-history plasticity, allowing them to adapt quickly to changing environmental conditions [2–4]. There has been growing speculation that cephalopod populations are proliferating in response to a changing environment, a perception fuelled by increasing trends in cephalopod fisheries catch [4,5]. To investigate long-term trends in cephalopod abundance, we assembled global time-series of cephalopod catch rates (catch per unit of fishing or sampling effort). We show that cephalopod populations have increased over the last six decades, a result that was remarkably consistent across a highly diverse set of cephalopod taxa. Positive trends were also evident for both fisheries-dependent and fisheries independent time-series, suggesting that trends are not solely due to factors associated with developing fisheries. Our results suggest that large-scale, directional processes, common to a range of coastal and oceanic environments, are responsible. This study presents the first evidence that cephalopod populations have increased globally, indicating that these ecologically and commercially important invertebrates may have benefited from a changing ocean environment.
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- Date Issued: 2016
Graphene quantum dots functionalized with 4-amino-2, 2, 6, 6-tetramethylpiperidine-N-oxide as fluorescence “turn-on” nanosensors
- Authors: Achadu, Ojodomo J , Britton, Jonathan , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239854 , vital:50773 , xlink:href="https://doi.org/10.1007/s10895-016-1916-y"
- Description: In this study, we report on the fabrication of simple and rapid graphene quantum dots (GQDs)-based fluorescence “turn-ON” nanoprobes for sensitive and selective detection of ascorbic acid (AA). Pristine GQDs and S and N co-doped-GQDs (SN-GQDs) were functionalized with 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4-amino-TEMPO, a nitroxide free radical). The nitroxide free radicals efficiently quenched the fluorescence of the GQDs and upon interaction of the nanoconjugates with ascorbic acid, the quenched fluorescence was restored. The linear ranges recorded were 0.5–5.7 μM and 0.1–5.5 μM for GQDs-4-amino-TEMPO and SN-GQDs-4amino-TEMPO nanoprobes, respectively. Limits of detection were found to be 60 nM and 84 nM for SN-GQDS-4-amino-TEMPO and GQDs-4-amino-TEMPO for AA detection, respectively. This novel fluorescence “turn-ON” technique showed to be highly rapid and selective towards AA detection.
- Full Text:
- Date Issued: 2016
HealthMessenger: an e-Health service to support ICT deployments in poor areas
- Authors: Gremu, Chikumbutso , Terzoli, Alfredo , Tsietsi, Mosiuoa
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430609 , vital:72703 , 10.1109/ISTAFRICA.2016.7530632
- Description: Development and implementation of appropriate e-services as well as revenue generation are key to deploying and sustaining ICT installa-tions in poor areas in developing countries. The area of e-Health is a promising area for e-Services that are important to populations in poor areas and health service organisations that are already spending mon-ey on different health initiatives in these areas. This paper discusses an e-Health service that facilitates dissemination of health information to people living in poor areas and that is subsequently used to generate revenue to support deployment and development of ICT in the areas. The tool was developed within the context of the Siyakhula Living Lab (SLL), a multi-stakeholder operation that promotes ICT for Development in the Eastern Cape Province of South Africa. Creation of health con-tent for the e-health service and its subsequent consumption happen in two different environments from a technological and social point of view. To enable this to happen, the e-service comprises two component applications that run in a peer-to-peer fashion. The component that is used to disseminate content for end-user consumption is called the HealthMessenger. The HealthMessenger is hosted on an environment called TeleWeaver, an application integration platform developed within the SLL to host software applications targeting people living in poor ar-eas. The platform is customised to support services with a revenue generation component.
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- Date Issued: 2016
Heat accumulation and development rate of massed maggots of the sheep blowfly, Lucilia cuprina (Diptera: Calliphoridae)
- Authors: Kotzé, Zanthé , Villet, Martin H , Weldon, Christopher W
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442168 , vital:73964 , https://doi.org/10.1016/j.jinsphys.2016.09.009
- Description: Blowfly larvae aggregate on exposed carcasses and corpses and pass through three instars before wandering from the carcass and pupating. The developmental landmarks in this process can be used by forensic entomologists to estimate the time since the insects colonised the carcass, which sets a minimum post mortem interval. Large aggregations of feeding larvae generate a microclimate with temperatures up to 15 °C above ambient conditions, which may accelerate larval development and affect forensic estimates of post-mortem intervals. This study investigated the effects of heat accumulated by maggot masses of Lucilia cuprina at aggregations of 20, 50 and 100 larvae, each at incubation temperatures of 18 °C, 24 °C and 30 °C, using body length and life stage as developmental indicators. Aggregation temperatures reached up to 18.7 °C above ambient temperature, with significant effects of both size and temperature of the aggregation on the development time of its larvae. Survivorship was highest for all life stages at 24 °C, which is near the developmental optimum of L. cuprina. The results of this study provide a broadly applicable method of quantifying heat accumulation by aggregations of a wide range of species of forensic importance, and the results obtained from such studies will demonstrate that ambient temperature cannot be considered the only source of heat that blowfly larvae experience when they develop on a carcass. Neglect of temperatures within larval aggregations will result in an overestimation of post-mortem intervals and thus have far-reaching medicolegal consequences.
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- Date Issued: 2016
Heterogeneity in virulence relationships between Cryptophlebia leucotreta granulovirus isolates and geographically distinct host populations: Lessons from codling moth resistance to CpGV-M
- Authors: Opoku-Debrah, John K , Hill, Martin P , Knox, Caroline M , Moore, Sean D
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417998 , vital:71500 , xlink:href="https://doi.org/10.1007/s10526-016-9728-1"
- Description: In South Africa, the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) is used to control the citrus pest Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae). However, the risk associated with continuous application of a single active ingredient is resistance. In order to manage resistance should it occur in field populations of T. leucotreta in South Africa, five new CrleGV genotypes from geographically distinct insect populations which were shown to exhibit some degree of phenotypic variation were recovered and genetically characterized. In droplet bioassays using seven CrleGV isolates against five T. leucotreta populations, some isolates were found to show higher virulence to some host populations than others. There were marked differences in the LD50 values of isolates and the number of occlusion bodies required per larva ranged between 0.79 and 3.12. The significance of these findings with respect to the application of CrleGV biopesticides and the management of resistance is discussed.
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- Date Issued: 2016
How content analysis may complement and extend the insights of discourse analysis: An example of research on constructions of abortion in South African newspapers 1978–2005
- Authors: Feltham-King, Tracey , Macleod, Catriona I
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/446258 , vital:74485 , xlink:href="https://doi.org/10.1177/1609406915624575"
- Description: Although discourse analysis is a well-established qualitative research methodology, little attention has been paid to how discourse analysis may be enhanced through careful supplementation with the quantification allowed in content analysis. In this article, we report on a research study that involved the use of both Foucauldian discourse analysis (FDA) and directed content analysis based on social constructionist theory and our qualitative research findings. The research focused on the discourses deployed, and the ways in which women were discursively positioned, in relation to abortion in 300 newspaper articles, published in 25 national and regional South African newspapers over 28 years, from 1978 to 2005. While the FDA was able to illuminate the constitutive network of power relations constructing women as subjects of a particular kind, questions emerged that were beyond the scope of the FDA. These questions concerned understanding the relative weightings of various discourses and tracing historical changes in the deployment of these discourses. In this article, we show how the decision to combine FDA and content analysis affected our sampling methodology. Using specific examples, we illustrate the contribution of the FDA to the study. Then, we indicate how subject positioning formed the link between the FDA and the content analysis. Drawing on the same examples, we demonstrate how the content analysis supplemented the FDA through tracking changes over time and providing empirical evidence of the extent to which subject positionings were deployed.
- Full Text:
- Date Issued: 2016
Impacts of HIV/AIDS on food consumption and wild food use in rural South Africa
- Authors: Ncube, Keitometsi , Shackleton, Charlie M , Swallow, Brent M , Dassanayake, Wijaya
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180412 , vital:43385 , xlink:href="https://doi.org/10.1007/s12571-016-0624-4"
- Description: HIV/AIDS can affect household food consumption in many ways, including through reductions in availability and quality of labour, reductions in earned income, and increased expenditure on medications. In rural South Africa, these negative effects can be buffered by social safety net programs provided by government and collection of wild foods. Despite some acknowledgement of the potential safety net role of wild foods, however, their contribution relative to other food sources in the context of HIV/AIDS remains underexplored. Here we report empirical findings from two rural communities in the Eastern Cape province of South Africa. Qualitative and quantitative methods were used to characterise food sources, intake and calories from 68 HIV/AIDS afflicted households and 87 non-afflicted households every quarter over 12 months. Results show that diets were moderately well-balanced though limited in variety, with cereal items contributing 52 % to total calorie intake. The bulk of food consumed by households was purchased, with supplementation from own production, collected wild vegetables and collected wild fruits. Up to 20 % of respondents from both HIV/ AIDS afflicted and non-afflicted households had insufficient daily caloric intake. Multivariate analyses show that, all else equal, individuals living in households afflicted by HIV/AIDS consumed fewer calories, had less diverse diets, and were more dependent on wild foods than those living in non-afflicted households. Given the detrimental effects of HIV/AIDS on income and home production, wild foods represent a free and readily available food source for vulnerable households.
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- Date Issued: 2016
Improvement of nonlinear optical properties of phthalocyanine bearing diethyleneglycole chains
- Authors: Britton, Jonathan , Martynov, Alexander G , Oluwole, David O , Gorbunova, Yulia G , Tsivadze, Yulia G , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/239812 , vital:50769 , xlink:href="https://doi.org/10.1142/S1088424616501042"
- Description: This paper reports the successful synthesis of the low symmetry phthalocyanines: metal-free 2,3-bis[2′-(2′′-hydroxyethoxy)ethoxy]-9,10,16,17,23,24-hexa-nn-butoxyphthalocyanine 1H22 and its zinc complex 1Zn along with their nonlinear optical (NLO) behavior in solution and in thin films. 1H NMR investigations evidenced of higher dissymmetry of electronic density in 1H22 in comparison with 1Zn. This dissymmetry is responsible for unusually higher values of Im[χ(3)χ(3)]/αα, βeffβeff, and γγ for 1H22in contrast to 1Zn, where the notable effect of heavy-metal enhancement of ISC was expected. Both compounds showed Im[χ(3)χ(3)]/αα values of the order of 10−11−11 in chloroform which are higher in comparison to the symmetrical octabutoxyphthalocyanine H2[(BuO)8Pc]. NLO properties of 1H22 were improved via its incorporation into polycarbonate polymeric matrix together with CdSe@CdS-TOPO quantum dots. In such composite the value of Im[χ(3)χ(3)]/αα was almost three times higher in comparison with 1H22 solution in chloroform. The obtained composites are expected to be perspective components of optical materials, capable of protection against strong light irradiation
- Full Text:
- Date Issued: 2016
Improving Fidelity in Internet Simulation through Packet Injection
- Authors: Koorn, Craig , Irwin, Barry V W , Herbert, Alan
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427786 , vital:72462 , https://www.researchgate.net/profile/Barry-Ir-win/publication/327622877_Improving_Fidelity_in_Internet_Simulation_through_Packet_Injection/links/5b9a1a47458515310583fd8a/Improving-Fidelity-in-Internet-Simulation-through-Packet-Injection.pdf
- Description: This paper describes the of extension implemented to the NKM Internet simulation system, which allows for the improved of injection of packet traffic at arbitrary nodes, and the replay of previously recorded streams. The latter function allows for the relatively easy implementation of Internet Background Radiation (IBR) within the simulated portion of the Internet. This feature thereby enhances the degree of realism of the simulation, and allows for certain pre-determined traffic, such as scanning activity, to be injected and observed by client systems connected to the simulator.
- Full Text:
- Date Issued: 2016
In search of the African voice in higher education: the language question
- Authors: Kaschula, Russell H
- Date: 2016
- Subjects: African languages -- Study and teaching (Higher) -- South Africa , Educational change -- South Africa , Education, Higher -- South Africa , Multiligualism , Language and languages -- Study and teaching
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59274 , vital:27539 , http://dx.doi.org/10.5842/49-0-658
- Description: This article seeks to understand what South African universities are doing by making use of language as a tool or as an enabling voice towards Africanisation and transformation with particular reference to Rhodes University, which serves as a case study. Although many universities now have language policies in place and are part of an enabling policy environment, when it comes to using language as part of transformation and asserting an African voice, there are still policy implementation challenges. It is argued in this article that implementation of policy, including university language policies, is now a key indicator for two levels of transformation; namely the more superficially visible or visual representation transformation, as well as deeper curriculum transformation through appropriate language usage. It is the latter form of transformation that largely eludes the contemporary South African university, whether these are historically black universities (HBUs) or historically white universities (HWUs). With the exception of a few best practices that are highlighted in this article, it is argued that transformation of the curriculum remains a long-term process, in the same way that language policy implementation is an ongoing process and requires commitment at all levels of university managerial and academic culture. The African voice in higher education remains an elusive one; though it is gaining ground, as evidenced by the recent removal of the Cecil John Rhodes Statue at the University of Cape Town. Furthermore, there is evidence of selected ongoing curriculum and pedagogic transformation, as presented in this article.
- Full Text:
- Date Issued: 2016