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Development of Palladium selective reagents and materials

- Moyo, Cyprian Bertrand

Authors: Moyo, Cyprian Bertrand
Date: 2016
Subjects: Palladium Palladium compounds -- Industrial applications Chemistry, Inorganic
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10948/12231 , vital:27046
Description: The adsorption and separation of Pd(II) from Pt(IV), Ir(IV) and Rh(III) by silica microparticles functionalized with triethylenetetramine (TETA), 2-(2-aminoethylthio)ethanamine (NSN) and 2-(2-(2-aminoethyl)ethylthio)ethanamine (NSSN) in 1 M hydrochloric acid medium was investigated by continuous column studies. The functionalized sorbent materials were characterized by microanalysis, SEM-EDS and FT-IR. Palladium selectivity of the sorbent materials was achieved by stripping of rhodium, iridium and platinum chlorido species with 0.5 M of NaClO4 in 1 M HCl while [PdCl4]2 was eluted with 3% w/v thiourea. The desorption efficiency of thiourea was confirmed by the SEM-EDS analysis of the materials after Pd(II) elution. Palladium loading capacity of the sorbents were in the order S-NSSN (23.85 mg/g) > S-NSN (12.70 mg/g) > S-TETA (4.97 mg/g). The extraction patterns on the sorbent materials were explained by considering the coordination chemistry of the ligand with [PdCl4]2ˉ and ionic interactions of [PtCl6]2ˉ and [IrCl5(H2O]ˉ. The square planar complexes, [Pd(HNSSNH)Cl2]Cl2 and [Pd(NSNH)Cl2][PdCl4]2, were isolated, analyzed by spectroscopy and single crystal X-ray, whereas evidence of the fraction of Pd(II)-TETA complex was obtained by HPLC studies. This provided proof of the inner sphere coordination mechanism as the mode of interaction of these ligands with [PdCl4]2ˉ. Trace amounts of Brˉ anions in ligands resulted in the inadvertent isolation of bromide coordinated Pd(II) NSN and NSSN complexes. The ion-pair salts of [TETAH4]4+ with [PtCl6]2ˉ, [IrCl6]3ˉ and [RhCl6]3ˉ were also isolated and characterized by microanalysis and IR to further explain the extraction patterns.
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Date Issued: 2016

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Development of part-of-speech tagger for Xhosa

- Delman, Xolani

Authors: Delman, Xolani
Date: 2016
Subjects: Computational linguistics -- Methodology Natural language processing (Computer science) Linguistic models
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10353/11872 , vital:39114
Description: Part-of-Speech (POS) tagging is a process of assigning an appropriate part of speech or lexical category to each word in a given sentence of a particular natural language. Natural languages are languages that human beings use to communicate with one another be it Xhosa, Zulu, English etc. POS tagging plays a huge and important role in natural language processing applications. The main applications of POS tagging include machine translation, parsing, text chunking, spell checkiXhosa (sometimes referred to as isiXhosa) is one of the eleven official languages of South Africa and is spoken by over 8 million South Africans. The language is mainly spoken in the Eastern Cape and Western Cape provinces of the country. It is the second most widely spoken native language in South Africa after Zulu (sometimes called isiZulu). Although the number of speakers might seem to be high, Xhosa is considerably under-resourced. There are very few publications in Xhosa, very few books have been published in the language and also the domains that use the language as a medium of instruction are very limited. However, the language is finding momentum nowadays. An Oxford approved Xhosa dictionary has been developed recently, and Xhosa newspapers that did not exist in the recent past are now published. Text from previously mentioned sources can then be combined to formulate a larger text that can be used to train the tagger. This work aims to develop an effective POS tagger for Xhosa. g and grammar. This thesis presents/describes the work that needed to be done to produce an automatic POS tagger for Xhosa. A tagset consisting of 36 POS tags/labels for the language were used for this purpose. These are listed. A total of 5000 words were manually tagged/labelled for the purpose of training the tagger. Another 3000 words were used for testing the tagger and these were disjoint from the manually tagged training data. The open source Stanford CoreNLP toolkit was used to create the tagger. The toolkit implements a Maximum Entropy machine learning model which was applied in the development of the tagger presented in this thesis. The thesis describes the implementation and testing processes of the model in detail. The results show that the development of the Xhosa POS tagging model was successful. This model managed to obtain a tagging accuracy of 87.71 percent.
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Date Issued: 2016

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Developmental and spatial variations in the diet signatures of hyperbenthic shrimp Nauticaris marionis at the Prince Edward Islands based on stable isotope ratios and fatty acid profiles

- Richoux, Nicole B, Allan, E Louise, Froneman, P William

Authors: Richoux, Nicole B , Allan, E Louise , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67923 , vital:29169 , https://doi.org/10.1016/j.csr.2016.02.0131
Description: Publisher version , The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.
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Date Issued: 2016

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Dialogues of sexualities: An action research project

- Graham, Nicola Susan Jearey

Authors: Graham, Nicola Susan Jearey
Date: 2016
Language: English
Type: Thesis , Masters , MA
Identifier: vital:3275 , http://hdl.handle.net/10962/d1021271
Description: Risky and abusive sexual behaviours, stemming largely from inequitable gendered norms, are a pervasive feature of the South African socio-sexual landscape. Literature shows that sexuality education programmes can be effective in reducing risky sexual practices, but South African school sexuality education has been shown to be largely inadequate. The question arises as to how to engage with high school learners about sexualities in meaningful ways. In an attempt to answer this, I implemented a dialogical sexuality action research project at a lower middle class urban high school. Freirian principles of critical consciousness and dialogical pedagogy were utilized, and these were infused with feminist post-structural understandings of a discursively constituted subject. The initial consultative process started in 2012 with two projects at the school. Data from these projects, and a further consultation with the school principal, provided baseline information on the gendered norms and the sexuality education in the school. I then instituted a dialogical sexuality intervention with a group of Grade 10 learners, aiming to bring gendered and sexual norms to visibility, to trouble them (thereby promoting participants’ critical consciousness around gendered norms), and to provide recognition for participants in a variety of subject positions. Ten sessions were conducted, with the focus of each session being planned by the group. The action research project attempted to promote understandings of the processes required to facilitate such aims. The dialogical format of the group generated curiosity and engagement, and there were suggestions that some participants were taking up safe-sex messages in a reflexive manner. A partial normalisation of some ‘hidden’ aspects of sex, particularly around issues pertaining to female sexuality, was enabled, and critical consciousness around the gendered inequities in ‘cheating’ was promoted. However, abstinence was relatively silenced, and male same-sex remained heavily stigmatised. No substantial action component beyond the group meetings was generated. Participant feedback indicated that they placed great value on the dialogical processes in the group, and that they enjoyed being able to talk about sexual and other personal aspects of their lives. I theorise that the value of the group was in the recognition that participants received as they were positioned in a variety of subject positions. Whilst dialogue was shown to be extremely valuable, there were suggestions that other, non-dialogical modes of recognition were also needed by participants.
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Date Issued: 2016

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Diatom-based water quality monitoring in southern Africa: challenges and future prospects

- Dalu, Tatenda, Froneman, P William

Authors: Dalu, Tatenda , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/124297 , vital:35590 , http://dx.doi.org/10.4314/wsa.v42i4.05
Description: Diatoms are of significant ecological importance in aquatic ecosystems, which stems from their dynamic position at the base of the trophic web as primary producers. Because diatom communities have specific environmental requirements and respond rapidly to changes in environmental conditions they are often employed as a cost-effective method to assess anthropogenic impacts and health statuses of aquatic ecosystems, particularly in Europe and North America. The purpose of this review is to summarise the challenges and future prospects associated with biological water quality monitoring using diatoms with special focus on southern Africa. Much work still needs to be carried out on diatom tolerances, ecological preferences and ecophysiology. It is recommended that past research pertaining to African diatom taxonomy should be made readily accessible to all through electronic media for use as a reference point. Moreover, following the same approach as for macroinvertebrate biomonitoring, African and other developing countries can resort to intermediate diatom taxonomy (i.e. genus), which is easier, less time-consuming and requires less-skilled personnel. While the lack of capacity and baseline information on diatom community composition and ecological requirements represent significant hurdles, diatom biomonitoring potentially holds much promise for understanding the ecological functioning and management of aquatic ecosystems in southern Africa. The application of diatom-based water quality assessment protocols has direct and immediate value for use as an ‘added-value’ assessment tool in addition to the use of macroinvertebrates and fish indices as these can indicate anthropogenically impacted and pristine sites.
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Date Issued: 2016

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Die hantering van etikette in woordeboeke, met spesiale verwysing na Xhosa-woordeboeke

- Landman, Kie-Mari, Kwatsha, Linda Loretta, Otto, PR

Authors: Landman, Kie-Mari , Kwatsha, Linda Loretta , Otto, PR
Date: 2016
Subjects: Xhosa language -- Lexicology Xhosa language -- Terms and phrases
Language: English
Type: Thesis , Masters , MA
Identifier: http://hdl.handle.net/10948/21845 , vital:29793
Description: The researcher’s decision to study the labelling of lexical items in dictionaries was prompted by the frustration experienced with subjective labelling in Afrikaans and English dictionaries. Some lexicographers rely too much on their subjective judgement when it comes to labelling lexical items. The problem with this is that the different dictionaries often label the same word differently or that words in the same dictionary which should get the same label are labelled differently. The question arose as to what exactly constitutes the correct handling of labels, especially with regard to Xhosa dictionaries. The search for an answer to achieve this aim dictated the necessity to examine the essence of the concept “label” in order to establish criteria for evaluating the effective usage of labels, because as Harteveld (1993:143) stated: “…the incorrect treatment of labels or the lack thereof can have important implications for a dictionary”. Since the hypothesis of this study is that it is possible to use labels objectively and correctly it is therefore possible to establish criteria that can be used to achieve this end. A literature review was undertaken to identify criteria for the handling of labels. Fieldwork with the aid of a questionnaire was conducted to supplement the establishment of such criteria. A number of criteria for handling labels was determined. Each criterion was discussed and its implementation was practically demonstrated by means of exemplars.
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Date Issued: 2016

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Diet of the endemic bivalve Solen cylindraceus inferred from stable isotope analysis in the Kariega Estuary, South Africa

- Nel, Holly A, Froneman, P William

Authors: Nel, Holly A , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67933 , vital:29170 , https://doi.org/10.1080/13235818.2016.1175917
Description: Publisher version , Sedentary filter-feeders such as the razor clam (Solen cylindraceus) are believed to indiscriminately exploit a carbon source derived from particulate organic matter (POM). POM demonstrates a high degree of spatial and temporal variability in composition, which may result in intraspecific dietary variation. This study aimed to investigate seasonal ontogenetic shifts in the feeding ecology of S. cylindraceus using dual stable isotopic (δ13C and δ15N) analyses in the oligotrophic temperate permanently open Kariega Estuary, South Africa. Mixing model results demonstrate that the different size classes of S. cylindraceus had a diet comprised mainly of POM. However, size grouping did have a significant effect on carbon and nitrogen signatures. Specifically, during winter, carbon isotopic signatures became more depleted with a decrease in size, while both winter and summer δ15N values became more nitrogen enriched with an increase in size. The observed trend in the ratios can likely be ascribed to the hydrodynamics of the system. Data from this study suggest that there may be some degree of variation among the different size cohorts, although this needs further investigation.
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Date Issued: 2016

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Digital capital: a mode of bridging capital for immigrant and refugee population

- Rosendahl, Patricia

Authors: Rosendahl, Patricia
Date: 2016
Subjects: Social capital (Sociology) -- United States , Immigrants -- United States
Language: English
Type: Thesis , Doctoral , DPhil
Identifier: http://hdl.handle.net/10948/3645 , vital:20449
Description: The resettlement of immigrant and refugee populations poses specific challenges to new host communities. Municipalities must find resources to assist these populations in transitioning into a new culture. Immediate needs are often adequate housing, health care, and primary schooling. While this transitioning process is still in play, the search for employment begins; often at the cost of consideration of longer-term needs, such as English or other host country language acquisition and planning for long-term career goals. Theorists in the field of social capital postulate that bonding and bridging social capital offers benefits for populations adjusting to new communities. Connections to like-minded individuals or pre-existing ethnic ties (bonding social capital) can provide support important to the well-being of individuals going through difficult social adjustments while connecting with new social groups (bridging social capital) can provide new information leading to expanding opportunities. The concept of bridging social capital for immigrant and refugee populations is the subject of this research study. It is situated within the context of our digital age in which information communication technology (ICT) is the primary mode of access to information and services. For the purpose of this thesis, the capability to exploit this mode of communication is thus identified as “digital capital.” As more and more governmental, educational, and social services are distributed within a technological environment, it is necessary to examine this mode of connection to information as a form of capital which can be viewed in a similar framework to other types of social capital. Access to technology and ICTs has been considered an integral element of the Development Goals as adopted by the United Nations for the Year 2000 Millennium Goals. Though later debates have questioned how ICTs may have benefited development goals, the pervasiveness of this form of information flow continues. Within Development Studies, Sen’s theory on the Capability Approach offers a valuable opportunity of connecting digital capital to development. Just as the Capabilities Approach accommodates the diversity of human values, characteristics, and functionings, so can digital capital provide flexibility through adaptation by the users to tailor the medium to meet specific needs. It is this freedom to adjust to individual needs and goals that allows this mode of bridging capital to hold a distinct advantage for immigrants and refugees who are searching for effective links into new social networks in the job search process. The role of the community college system has been at the forefront of providing educational training and social acclimation for this population in their quest for economic self-sufficiency in the resettlement process. A greater understanding of the role that technology plays in the success of immigrant and refugee resettlement is vitally important for the well-being of communities undergoing dynamic demographic change.
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Date Issued: 2016

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Diplomatic relations and their impact on development: the case of South Sudan and Uganda

- Legge, Mikaya Modi Lubajo

Authors: Legge, Mikaya Modi Lubajo
Date: 2016
Subjects: International economic relations South Sudan -- Foreign relations -- Uganda , Uganda -- Foreign relations -- South Sudan
Language: English
Type: Thesis , Masters , MA
Identifier: http://hdl.handle.net/10948/15365 , vital:28226
Description: Since Sudan’s Comprehensive Peace Agreement (CPA) was signed in 2005, its border with Uganda has become a hub of activities. These economic activities have been enhanced by ethnic and political relations, but also by diplomatic relations between the two countries. Contrasting developments on the Ugandan side of the border with those on the South Sudanese side, this research draws on empirical fieldwork to examine the impact of diplomatic relations on the development between both countries since 2005, with international trade as the main aspect of development. The study sets out to show how trade between both countries has been affected by the diplomatic relations between them. The post-CPA demand for goods and state-building processes created a range of economic opportunities for traders. This was particularly the case for Ugandan large-scale traders who, as a result, became an important and empowered group. These factors have further been enhanced by good diplomatic relations between both countries, and as a result South Sudan has become Uganda’s most important trading partner as well as a destination for many Ugandans to conduct their trade. Simultaneously, post-conflict problems have emerged in South Sudan such as insecurity, weak government institutions run by incompetent officials, corruption, high foreign exchange rate, cultural diversity, mistrust and poor infrastructure. These problems have emerged as major challenges to trade and investment by Ugandan traders in South Sudan with traders as well as government officials agreeing that these challenges present major setbacks to trade and investment in South Sudan. Ugandan small-scale traders in particular have become more vulnerable to expressions of authority on the part of South Sudan’s post-CPA state, in which state or individual military might is used effectively to control trade. The current conflict, which began in December 2013, has added a new dimension to the list of impediments to trade as insecurity and economic instability have precipitated an atmosphere of uncertainty among many traders and investors. Despite all those challenges, Ugandan traders as well as government officials still view South Sudan as a business destination of choice. Overall, the study confirms that diplomatic relations have enhanced international trade between South Sudan and Uganda by way of solving trade disputes, investment promotion and influencing leadership on policy matters.
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Date Issued: 2016

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Disaster management policy options to address the sanitation challenges in South Africa

- Hoossein, Shafick, Tandlich, Roman, Whittington-Jones, Kevin J, Laubscher, Richard K, Madikizela, Phindile, Zuma, Bongumusa M

Authors: Hoossein, Shafick , Tandlich, Roman , Whittington-Jones, Kevin J , Laubscher, Richard K , Madikizela, Phindile , Zuma, Bongumusa M
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/75938 , vital:30485 , https://www.neha.org/node/28591
Description: The current population of South Africa has been migrating into informal urban settlements that lack adequate sanitation service delivery, caused at least in part by the lack of the necessary skills in the local government sector and the lack of buy in from the community into the provided sanitation facilities. The authors report results of policy research into the relevant disaster management options that could be applied to improve the sanitation service delivery in South Africa. The best policy option was identified as the draft Disaster Management Regulations: Disaster Management. Local government can use these tools through the formation of the volunteer units from the nongovernmental organization sector, the business community, and from among the end users of sanitation facilities. Formation of the volunteer unit should follow the principles of cooperative governance and participatory approach to disaster management. Implementation should be facilitated through the adoption of locally specific municipal by laws.
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Date Issued: 2016

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Disentangling the identities and distribution patterns of the introduced beachfleas Orchestia gammarellus and Platorchestia platensis (Crustacea: Amphipoda Talitridae) in South Africa

- Diemer, Natalie, Griffiths, Charles L, Hodgson, Alan N

Authors: Diemer, Natalie , Griffiths, Charles L , Hodgson, Alan N
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/443163 , vital:74084 , https://doi.org/10.1080/15627020.2016.1268930
Description: Two introduced beachfleas, Orchestia gammarellus and Platorchestia platensis, have been recorded from South Africa, but have been misidentified by some earlier researchers and, prior to this study, each was also known from just a few, scattered observations, such that their true distributions remained obscure. We illustrate both species to clarify the features that identify and distinguish them and determine their true distributions by re-examining historical samples and by collecting new material from estuaries and lagoons along the west and south coasts of South Africa. Adult males of O. gammarellus have slender antennae and characteristic expanded, flattened, oar-like distal segments on pereopod 7. Adult males of P. platensis have the peduncle of antenna 2 strongly swollen and have bulbous, but not flattened, distal segments on pereopod 7. Both species occur under wrack and other debris along the banks of estuaries and sheltered lagoons. Orchestia gammarellus is found only along the south-west coast, in the Berg River Estuary, Langebaan Lagoon and the Diep River Estuary. Previous records from Knysna were misidentifications of P. platensis. Platorchestia platensis is found at one west coast site, Langebaan Lagoon, but is widely distributed from Cape Point eastwards to at least Algoa Bay. Both species share the same habitats as several other native beachfleas and competitive interactions between native and introduced species merit investigation.
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Date Issued: 2016

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Dispute resolution

- Arendse, Jacqueline A, Clegg, David, Williams, Robert C

Authors: Arendse, Jacqueline A , Clegg, David , Williams, Robert C
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , book chapter
Identifier: http://hdl.handle.net/10962/131084 , vital:36522 , https://store.lexisnexis.co.za/products/silke-on-tax-administration-skuZASKUPG1440
Description: Chapter 9 of the Tax Administration Act 2011, deals with the objection and appeals processes of the tax Acts administered by SARS in terms of s 4 of the SARS Act, 1997. A taxpayer who is aggrieved by an assessment or a decision in which he has an interest, has the right to object against the assessment or decision.
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Date Issued: 2016

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Distribution and ecological assessment of heavy metals in irrigation channel sediments in a typical rural area of south China

- Gu, Chiming, Liu, Yi, Li, Zhiguo, Mohamed, Ibrahim, Zhang, Ronghua, Brooks, Margot, Chen, Fang

Authors: Gu, Chiming , Liu, Yi , Li, Zhiguo , Mohamed, Ibrahim , Zhang, Ronghua , Brooks, Margot , Chen, Fang
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/66924 , vital:29000 , ISSN 0925-8574 , https://doi.org/10.1016/j.ecoleng.2016.01.054
Description: Publisher version , Elevated levels of heavy metals in sediments of irrigation channels can pose risks for crops and livestock, as well as for human health. In this study sediment samples were collected from the irrigation channel in a typical rural area of south China, and digested, in order to analyze their contents for the presence of heavy metals Cu, Zn, Pb, Cr, Cd, and Ni, as well as the non-metal As, to assess total concentrations and pollution levels. The pollution load index and potential ecological risk index of these elements were utilized to assess contamination levels and ecotoxicity. Our results showed that the concentrations of the 7 elements were in the order of Zn > Ni > Cr > Cu > As > Pb > Cd. With the exception of Cr and Pb, concentrations of elements were higher than their background in soil, especially for Cd (1.79 mg kg−1), As (99.61 mg kg−1) and Ni (142.62 mg kg−1), which were 18.49, 8.89 and 5.30 times their background concentrations, respectively. The whole sampled zone was characterized by medium pollution and had a very high potential ecological risk. The area of arable land presented a medium pollution risk, while areas near to the path or road showed high risk of pollution. The predominant contributors to elevated ecological risk for the whole zone were Cd and As.
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Date Issued: 2016

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Distribution and use of cash income from basket and mat crafting: Implications for rural livelihoods in the Eastern Cape, South Africa

- Adam, Y O, Shackleton, Charlie M

Authors: Adam, Y O , Shackleton, Charlie M
Date: 2016
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/180434 , vital:43388 , xlink:href="https://doi.org/10.1080/14728028.2016.1186576"
Description: The objective of this paper was to investigate the extent to which baskets and mats local trade contributes to rural livelihoods of the crafters’ household and community downstream income. Primary data were collected through structured interviews with 83 crafters from Noqhekwana village in Port St. Johns municipality using snowball sampling in May, 2015. The survey was supplemented by secondary data and direct observations. The findings show that crafting contributed 35% of crafter’s household total income. The received income is spent on expenses in the household and downstream actors depending on the crafter’s priorities. Lack of organization between crafters, access to sufficient raw material, and low prices were identified as major challenges involved in the production and trade of the products.
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Date Issued: 2016

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Distribution of benthic diatom communities in a permanently open temperate estuary in relation to physico-chemical variables

- Dalu, Tatenda, Richoux, Nicole B, Froneman, P William

Authors: Dalu, Tatenda , Richoux, Nicole B , Froneman, P William
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/67943 , vital:29172 , https://doi.org/10.1016/j.sajb.2015.06.004
Description: Publisher version , The spatial and temporal patterns in benthic diatom community structure in temperate permanently open estuaries are poorly understood. In this study, we used a combination of multivariate and diversity indices to elucidate environmental factors associated with diatom community structure in the Kowie Estuary, South Africa. Benthic diatom samples were collected from three sites corresponding to the upper, middle and lower reaches of the estuary on four occasions over the period early spring 2012 to winter 2013. Among the 89 benthic diatoms observed, Entomoneis paludosa (W Smith) Reimer, Nitzschia reversa W Smith, Nitzschia closterium (Ehrenberg) W Smith, Pleurosigma elongatum W Smith, P. salinarum (Grunow) Grunow, Staurosira elliptica (Schumann) DM Williams & Round, Surirella brebissonii Krammer & Lange-Bertalot, and Surirella ovalis Brébisson were the numerically dominant species. Principal component analysis demonstrated that the diatom community structure was determined by a variety of factors including nutrient (ammonia, nitrate) concentrations, hydrology (e.g., water depth and flow) and pH. Hierarchical cluster analysis revealed the absence of any distinct spatial patterns, although distinct benthic diatom communities were recorded during the different sampling periods. The species richness was highest in the middle reach, decreasing from early spring to summer in all reaches. The results of the study provide important insights into the various factors that structure benthic diatom community composition within a permanently open temperate southern African estuary.
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Date Issued: 2016

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Distribution of Escherichia coli O157:H7 in irrigation water, drinking water troughs, dairy wastewater and rectal swabs from three dairy farms in Amathole district municipality, Eastern Cape, South Africa

- Myataza, Asive https://orcid.org/0000-0001-5483-122X

Authors: Myataza, Asive https://orcid.org/0000-0001-5483-122X
Date: 2016
Subjects: Escherichia coli O157:H7 , Irrigation water
Language: English
Type: Master's theses
Identifier: http://hdl.handle.net/10353/24150 , vital:62397
Description: Escherichia coli belongs to the genus Escherichia which has five species, including E. hermanii, E. fergusonii, E. vulneris, E. blattae and E. coli (Willshaw et al., 2001). Some E. coli strains are pathogenic, and such strains are differentiated into different pathotypes based on the virulence factors they possess, mechanisms of pathogenesis, clinical manifestation and serotyping of their somatic, flagella and capsule (O, H and K) antigens; while some are nonpathogenic (Dikobe et al., 2011). These strains have been grouped into major pathotypes namely: enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enterohaemorrhagic E. coli (EHEC), uropathogenic E. coli (UPEC) and neonatal meningitis E.coli (NMEC) (Willshaw et al., 2001; Villegas-sepulveda et al., 2003; Kaper et al., 2004; Bugarel et al., 2011). Members of EPEC pathotype are Shiga-toxin producing (STEC) organisms, with E. coli O157:H7 serotype being recognized as the most frequent STEC serotype linked to diseases in human (Barkocy-Gallagher et al., 2001; Coombes et al., 2011; Dikobe et al., 2011; Jacob et al., 2013). E. coli O157:H7 is the major cause of haemorrhagic diarrhoea and haemolytic uremic syndrome (UHS) in humans, due to the production of Shiga-toxins that are similar to Shigella toxins (Villegas-sepulveda et al., 2003; Ngwa et al., 2013). These toxins are coded by genes which allow them to penetrate small intestines of human and animals (Chern et al., 2011). Dairy products and cattle are the major reservoirs of haemorrhagic E. coli O157: H7 (Elder et al., 2000; Elmali et al., 2005; Ayaz et al., 2014). Haemorrhagic E. coli O157:H7 is carried mostly in the gastrointestinal tracts of cows and other ruminants (Gun et al., 2003)and it is transmitted through ingestion of contaminated food and water, or through direct and indirect contact with infected cows and other ruminants and/or via a person to person transmission (Lahti et al., 2003). Almost 70percent of countries in the world use poorly treated water for irrigation; this is inclusive of developing countries, which lack well developed means of adequate water treatment due to unavailable financial resources (Gerba et al., 2011). Most communities in the Eastern Cape Province of South Africa are rural with poor water supply with majority of them relying on ground and surface waters that are impacted by insufficiently treated municipal water (which may harbour many pathogens) for domestic purposes (Ateba et al., 2008). Cows may contaminate drinking, recreational and irrigation waters with faecal matters or through direct contact with water (Solomon et al., 2002; Chern et al., 2011). A number of countries with water shortage tend to use insufficiently treated water for irrigation, leading to further contamination of irrigated crops (Fatoki et al., 2001). This has all resulted to elevated levels of E. coli O157:H7 related disease outbreaks and deaths of humans (Olsen et al., 2002). , Thesis (MSc) -- Faculty of Science and Agriculture, 2016
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Date Issued: 2016

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Diversity and distribution of lepidopteran stem borers and their wild host plants in Western Cape and KwaZulu-Natal provinces, South Africa

- Kokwana, Bongiwe

Authors: Kokwana, Bongiwe
Date: 2016
Subjects: Stem borers--South Africa Pests--South Africa Grain--Diseases--South Africa
Language: English
Type: Thesis , Masters , Entomology
Identifier: http://hdl.handle.net/10353/11729 , vital:39101
Description: Lepidopteran stem borers are infamous among cereal crops and sugarcane growers because of their pests status in these crops. Lepidopteran stem borers often infest cereal crops such as maize (Zea mays L.), sorghum (Sorghum bicolor L.), pearl millet (Pennisetum glaucum L.), sugarcane (Saccharum spp.). However, in natural habitats, the stem borers feed on a wide variety of wild host plants species in the Poaceae, Cyperaceae and Typhaceae families. Some wild host plants in close approximation of cultivated fields act as reservoirs for stem borers during the absence of cultivated crops. Understanding of the diversity of the stem borers, their host plants and their interactions was very important in development of management strategies for the stem borer populations. For an example, grasses such as Napier grass (Pennisetum purpureum Schumach.) and Sudan grass(Sorghum vulgare var. Sudanense (Piper) Hitchc.) act as trap plants whereas other grasses such as Molasses grass (Melinis minutiflora P. Beauv.) and legume silverleaf (Desmodium uncinatum (Jacq.) DC.) act as repellents to stem borer moths. In South Africa, studies on the diversity and distribution of lepidopteran stem borers in wild habitats are limited. Previous studies concentrated on diversity, abundance, and distribution of stem borers and their natural enemies on cultivated crops because of the economic importance of cultivated crops. In view of the foregoing, this study was conducted to investigate the diversity and distribution of lepidopteran stem borers and their host plants in wild habitats in the Western Cape and KwaZulu-Natal Provinces of South Africa and to generate mtDNA COI sequences of the stem borer species in natural habitats. These sequences can be accessed in databases and assist in identification of previously unknown stem borers in cultivated crops. Therefore this study contributes to development of monitoring and early identification tool of the stem borer movements between host plants assemblages. Surveys were conducted in Western Cape and KwaZulu-Natal provinces, South Africa during the rainy season of 2014 and 2015 in 38 localities to catalogue the diversity of lepidopteran stem borers in wild host plants. The sites visited belonged to five vegetation types: grassland, the Indian Ocean coastal belt, savanna, forest, and wetlands. A total of 237 lepidopteran stem borers was collected during study yielding 21 species that belonged to Noctuidae (Acrapex sp. 89, Acrapex sp. 90, Acrapex sp. 92, Acrapex sp., Acrapex minima, New genus NG11), Sesamia calamistis Hampson, Sesamia sp., Sesamia natalensis Le rü sp. nov., Sesamia nov sp. 4, Sesamia nov sp.36, Conicofrontia bipartita Hampson, Conicofrontia sesamoides Hampson, Conicofrontia diamensa Hampson, Pirateolea piscator Fletcher , Sciomesa mesophaea Aurivillius), Crambidae(Chilo partellus Swinhoe and Calamotropha paludella Hibner) Pyralidae (Phycitiinae sp. 1 and Phycitiinae sp. 2) and Tortricidae were recorded from 20 wild host plant species. Stem borer wild host plants species were Cymbopogon dieterlenii Stapf ex Schweick.,Cymbopogon nardus (L.) Rendle, Cymbopogon pospischilii (K. Schum.) C.E. Hubb., Digitaria macroglossa Henrad, Eriochloa meyeriana (Nees) Pilg.,Eriochloa fatmensis (Hochst. &Steud.) Clayton, Imperata cylindrica (L.) Raeusch., Miscanthus capensis (Nees) Andersson, Paspalum urvillei Steud., Panicum maximumJacq., Pennisetum purpureum Schumach., Phragmites australis (Cav.) Trin. Ex Steud.,Rottboellia cochinchinensis (Lour.) Clayton, Setaria homonyma (Steud.) Chiov.,Sorghum arundinaceum (Desv.) Stapf.,Cyperus divesDelile, Cyperu sdistans Pursh, Cyperus fastigiatus Rottb., Cyperus sexangularis Nees and Typha latifolia (L.).The diversity of stem borer species varied among vegetation types, host plants, and altitude. Morphological identification of specimens from these surveys indicated a high diversity of stem borer species in the Noctuidae family, followed by Pyralidae, Crambidae, and Tortricidae respectively. Of all the stem borers collected in the two provinces, noctuid species were most abundant in all vegetation types from low to high altitudes representing 62.45percent, whereas pyralids, crambids, and tortricids made up 26.58percent, 9.28percent, and 1.69percent respectively. The diversity and distribution of stem borers were affected by latitude. KwaZulu-Natal had higher latitudes ranging between -28.37717˚ and -31.07800˚ and had higher diversity, distribution and the of stem borers host plants, while Western Cape Province had lower diversity and distribution at latitudes ranging between -34.00280˚ and -34.05343˚. Morphological identification of stem borers was complemented with the mtDNA cytochrome oxidase I gene (COI) to investigate evolutionary relationships between the stem borer species collected in this study. Of the 12 sequences searched from the databases and the Genebank only five sequences were identified to species level; UFH024 was identified as Sciomesa mesophaea, the other four were identified as Conicofrontia sesamoides, Conicofrontia bipartita; and the first ever record of Calamotropha paludella in South Africa and Pirateolea piscator. Five sequences; UFH026, UFH028, UFH029, UFH030, UFH032 were only identified to order.
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Date Issued: 2016

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Diversity and ecological role of true crabs (crustacea, brachyura) in the St Lucia Estuary, iSimangaliso Wetland Park, in response to global change

- Peer, Nasreen

Authors: Peer, Nasreen
Date: 2016
Subjects: Crustacea -- South Africa -- KwaZulu-Natal Crustacea -- South Africa -- Saint Lucia, Lake , Global environmental change
Language: English
Type: Thesis , Doctoral , PhD
Identifier: http://hdl.handle.net/10948/45558 , vital:38669
Description: This work has explored novel concepts of crab vulnerability, recovery and resilience under unprecedented climatic changes in South Africa’s first UNESCO World Heritage Site. By showing how large salinity shifts and prolonged interruption of the marine connection can drastically affect brachyuran diversity and community structure in St. Lucia Lake, the potential cascading effects on ecosystem functioning were estimated. Only 15 crab species were recorded within the system during this study, compared to the 26 species that were known to occur prior to the recent environmental shift (i.e. 58% decline). The impact of this biodiversity collapse has negatively affected the associated mangrove ecosystem in particular, with the entire community of fiddler crabs persisting only in a small area near the estuary mouth. Gut fluorescence measurements have shown that, due to a lack of tidal Influence, their grazing impact on microphytobenthic biomass may become unsustainable. However, although adults are able to survive in this environment, the larvae require a marine connection; and they are thus unable to tolerate the wide fluctuations in salinity currently prevailing in the system. The study concludes that brachyurans are key factors to consider during conservation planning, as they are crucial to maintaining ecosystem function in the face of environmental change. This research is of global relevance, as many similar estuarine and coastal lakes around the world are currently experiencing similar state shifts. All six chapters included in the thesis have already been published in the peer-reviewed literature; and the project results have also earned Nasreen the NRF award of Next-Generation Researcher of the Year for 2015.
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Date Issued: 2016

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Diversity of bacteria isolated from the flies Musca domestica (Muscidae) andChrysomya megacephala (Calliphoridae) with emphasis on vectored pathogens

- Brits, Devon, Brooks, Margot, Villet, Martin H

Authors: Brits, Devon , Brooks, Margot , Villet, Martin H
Date: 2016
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/66904 , vital:28998 , ISSN 1021-3589 , https://doi.org/10.4001/003.024.0365
Description: Publisher version , We evaluated the bacteria occurring externally on Musca domestica and Chrysomya megacephala, the two most common synanthropic flies which may be found at many refuse sites throughout the world. Bacteria cultured from 10 specimens of each species were isolated, Gram-stained and examined microscopically, and divided into morphologically distinct ‘pseudospecies', to avoid excessive duplication of genetic identification. About 350 bp of the 16S ribosomalRNAgene was amplified from genomicDNAextracted from each ‘pseudospecies', sequenced, and bacteria identified using BLASTn. Nineteen different types of colony were identified from M. domestica, with Pseudomonas sp. and Swine Manure Bacterium SP14 being most abundant. Chrysomya megacephala yielded 15 distinct pseudospecies with total colony counts approximating to 10 000 from 10 plates, where 80 % of colonies were non-pathogenic Bacillus pumilus. A total of 18 species were identified genetically: three shared by the fly species; four unique to C. megacephala, and 13 unique to M. domestica. Half of these 18 species were pathogenic, two or three others were food spoilers and the rest were environmental or commensal bacteria from soil or plant matter. This study added three new pathogenic strains of bacteria and one new environmental strain to the list of bacteria reported to be vectored by these flies.
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Date Issued: 2016

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