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Developing macroinvertebrate trait- and taxonomically-based approaches for biomonitoring wadeable riverine systems in the Niger delta, Nigeria

  • Authors: Edegbene, Ovie Augustine
  • Date: 2020
  • Subjects: Water – Pollution -- Nigeria -- Niger River Delta , Stream health -- Nigeria -- Niger River Delta , Water -- Pollution -- Measurement , Environmental monitoring -- Nigeria -- Niger River Delta , Water quality -- Nigeria -- Niger River Delta , Water quality biological assessment -- Nigeria -- Niger River Delta , Aquatic invertebrates -- Nigeria -- Niger River Delta , Stream restoration -- Nigeria -- Niger River Delta , Urban agriculture -- Nigeria -- Niger River Delta , Stream ecology -- Nigeria -- Niger River Delta
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/140660 , vital:37907
  • Description: Riverine systems are increasingly subjected to pollution due to rapid urbanisation, industrialisation, and agricultural activities. Increasing pollution in freshwater systems impairs water quality, causes biodiversity loss and impairs aquatic ecosystem functionality and supply of ecosystem services. Rivers in the Niger Delta region of Nigeria are particularly vulnerable to urban pollution and agricultural activities as natural forests are increasingly replaced by urbanisation and agriculture. The differential effects of these pressures on the ecological processes of these river systems are poorly explored, as is the development of appropriate biomonitoring tools for routine monitoring of river health. In this study, a physico-chemically-based approach and macroinvertebrate trait- and taxonomic- approaches were developed to better understand the effects of multiple pressures on riverine systems, while developing multimetric indices to enable sustainable management of rivers within the region. Sixty-six stations in 20 river systems within the Edo and Delta States of the Niger Delta ecoregion were monitored seasonally for a period of five (2008–2012) years. The physico-chemically based approach makes apparent the extent of degradation of rivers and streams in the Niger Delta. For each dominant land use type, river stations were classified into least impacted stations (LIS), moderately impacted stations (MIS) or heavily impacted stations (HIS). Of 11 stations within urban catchments, only two were considered least impacted, suggesting that urgent measures are necessary to revise the current trajectories of urban rivers within the region. Most of the stations designated as MIS and HIS in the urban and urban-agriculture catchments were found to be significantly correlated with increased nutrients, EC and BOD5. Characteristics of most of the MIS and HIS within rivers in urban catchments evidenced the so-called urban stream syndrome, a state of persistent degradation of urban streams. The results of the traits and ecological preferences approach showed traits sensitive to urban and urban-agriculture pollution. Traits and ecological preferences that were associated with the LIS include the possession of hardshell, moderate and high sensitivities to oxygen depletion, very large body sized individuals (>20-40mm), swimmers, flattened body shape, a preference for temporary attachment, crawling, respiration with aerial/vegetation, possession of breathing tubes, possession of strap or other apparatus for respiration, streamlined body, and a high sensitivity to oxygen depletion. Permanent attachment as an ecological preference associated with LIS was also positively correlated with increasing dissolved oxygen (DO) and was deemed a pollution sensitive ecological preference. The possession of very small body size (<5mm), associated with HIS, was deemed a pollution-tolerant trait and was negatively correlated with DO, confirming the deteriorating state of the urban and urban-agricultural rivers. The impact of urban-forestry pollution on the distribution pattern of macroinvertebrate traits and ecological preferences was also explored in the selected rivers. Traits and ecological preferences such as possession of hard-shell, large body size, and grazing as a feeding preference which were significantly positively associated with the LIS, were also either significantly positively correlated with DO, or significantly negatively correlated with increasing any two of flow velocity, water temperature, BOD5 and nutrient. These traits and ecological preferences were deemed sensitive in forested rivers receiving urban pollution. Further, burrowing, the pupa aquatic stage, and predation which were significantly positively associated with HIS on the RLQ ordination, were also significantly negatively associated with DO. These traits were deemed tolerant of forested systems receiving urban pollution. Multimetric indices (MMI) were developed, validated and applied for urban, urban-agriculture and urban-forested (MMI-urban, MMI-urban-agric and urban-forest) areas. Of the 26 metrics that satisfactorily discriminated between the LIS, the MIS, and the HIS for MMI-urban, only five metric were retained for integration into MMI-urban, they are log VeL, Hemiptera abundance, % Coleoptera + Hemiptera, % Chironomidae + Oligochaeta and Evenness index. Further, of the 18 metrics that satisfactorily discriminated between the LIS, the MIS, and the HIS for MMI-urban-agric, only 12 metrics were retained and nine proved to be redundant. The nine metrics represent different measures; two of them were retained in addition to Chironomidae/Diptera abundance, % Odonata and Oligochaeta richness. The two metrics selected in addition to the hironomidae/Diptera abundance, % Odonata and Oligochaeta richness were the Margalef index and the logarithm of relative abundance of sprawler. For the MMI-urban-forest, 14 metrics satisfactorily discriminated between the LIS, the MIS, and the HIS, and 12 metrics were retained and 11 proved to be redundant. The non-redundant metric was Trichoptera abundance. Three metrics were further selected in addition to the Trichoptera abundance which include % Chironomidae + Oligochaeta, Coleoptera + Hemiptera richness and Shannon diversity. The MMI-urban and MMI-urban-agric indices performed better for LIS designated stations compared to the MIS and HIS deignated stations. The developed indices proved effective as biomonitoring tools for assessing the ecological health of rivers in the urban and urban-agriculture catchments within the Niger Delta. Overall, the results of the macroinvertebrate traits and ecological preferences, and taxonomic approaches showed the strength in the complementarity of both approaches in developing biomonitoring tools for assessing levels of deterioration in riverine systems. The study contributes significantly to understanding the ecology of riverine systems in the Niger Delta, particularly those subject to urban stresses, agricultural activities and urban pollution in forested systems, and thus makes an important contribution to the science and practice of biomonitoring in Nigeria where such studies are sparse.
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Developing social indicators for the evaluation of natural resource management programmes using a capability approach in the Eastern Cape, South Africa

  • Authors: Human, Johanna Susanna
  • Date: 2020
  • Subjects: Environmental education -- South Africa -- Eastern Cape , Natural resources -- Management -- Study and teaching (Continuing education) -- South Africa -- Eastern Cape , Sustainable development -- Study and teaching (Continuing education) -- South Africa -- Eastern Cape , Environmental economics -- Study and teaching (Continuing education) -- South Africa -- Eastern Cape , Subsistence farming -- South Africa -- Eastern Cape , Watersheds -- South Africa -- Eastern Cape , Capabilities approach (Social sciences) , Tsitsa River Catchment (Eastern Cape, South Africa)
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10962/147348 , vital:38628
  • Description: The dissertation investigates how the capability approach can be used to develop social indicators for a natural resource management (NRM) programme. The study aimed to develop an understanding of what the beneficiaries of the programme value being and doing to guide the development of social indicators that will take into consideration their personal development aspirations. These valued beings and doings were then overlaid with the programme goals and objectives to identify and select the final indicators. The study was situated in the Tsitsa catchment in the Eastern Cape, South Africa and was part of a natural resource management programme, focused on land restoration and avoided degradation. Methods used to collect data for this study and develop an understanding of what the residents’ valued beings and doings were, included semi-structured interviews, workshops and document analysis. The research population was non-homogenous. I tried to include voices representing different prominent groups of land users in the study. This included established commercial farmers, emerging commercial farmers, commercial forestry, residents residing in communal areas and engaged with subsistence farming and residents from these communal areas who are now residing elsewhere but continue to have connections to the catchment. Understanding the voices of these different groups who reside in the catchment was important to develop an inclusive understanding of what residents of the catchment valued beings and doings were. The research process was supported by participatory approaches. This process, and the lessons learnt during the research process, were valuable for the further development and implementation of the planned participatory monitoring evaluation reflection and learning (PMERL) framework. The research process involved learning from the research participants about their valued beings and doings and what was important for the programme implementers. Some of the research participants from the Rhodes University implementation team (RUIT) were also involved in selecting the indicators they thought the programme should monitor. Overall, using the capability approach helped me to gain insight and understanding with regard to what the valued beings and doings are for the residents of the catchment and what they would like development programmes, such as the Tsitsa Project, to address. It was surprising to find many areas of overlap between the valued beings and doings of the different residents in the catchment, as well as the similarities between these and the goals and objectives of the Tsitsa Project. In conclusion, using the capability approach was useful to learn what was important for the residents of the catchment to help develop the social indicators but also to learn how to guide and steer participatory monitoring and evaluation processes in the future.
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Developing voice and leadership amongst a group of class captains

  • Authors: Nehunga, Jacobina Taukondjele
  • Date: 2020
  • Subjects: Educational leadership -- Namibia , Transformational leadership -- Namibia , Leadership in adolescents -- Namibia , Rural schools -- Namibia , School children – Namibia -- Attitudes , School management and organization – Namibia , Cultural Historical Activity Theory
  • Language: English
  • Type: Thesis , Masters , MEd
  • Identifier: http://hdl.handle.net/10962/145034 , vital:38402
  • Description: The notion that leadership can be reduced to that of a formal position such as principalship has become problematic in school leadership research and practice, globally and also in Namibia. It appears that when leadership is concentrated only at the level of a principal within schools, teachers and learners within the same school experience a lack of opportunities to contribute to leadership practices, thus losing a sense of ownership. Supporting a distributed leadership perspective and embracing transformative leadership, this study investigated how learner voice and learner leadership (see for example Mitra and Gross, 2009) can be developed within a group of class captains in a combined school in rural Namibia. Cultural Historical Activity Theory (CHAT) underpinned the study which is located within a critical paradigm. Findings of the study were captured into two phases whereby phase one generated contextual profiling findings through the adoption of qualitative methods such as questionnaires, interviews, document analysis and two other participatory methods of mapping and transect walks. Phase two findings were captured through expansive learning actions in Change Laboratory Workshops. Observation notes, video recording and photographs and informal discussions were used as data sources during this phase. Both inductive and abductive analysis were employed. The findings revealed that a few enabling conditions to class captainship practice existed, but generally there was limited participation of class captains in school leadership. Class captains were seen as merely class representatives and their leadership was confined to a classroom level in the school. They performed more managerial tasks than leadership. It was also revealed that class captainship is not a documented practice in Namibia and it lacks support. Against this backdrop, during phase two of the study, seven contradictions were identified and two contradictions were prioritised for resolution during the Change Laboratory Workshops. Some of the resolutions included the development of a school based guiding document for class captains; an establishment of a class captainship club; and the promotion of a yearly election campaign of class captains. The study recommends more interventionist studies to be conducted on class captainship in order to see the practice documented in terms of policy in Namibia, perhaps in the near future.
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Development and assessment of a fixed dose combination of perindopril arginine and indapamide loaded microparticles

  • Authors: Mandava, Tavonga Tyomai
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/164413 , vital:41116
  • Description: Thesis (MSc)--Rhodes University, Faculty of Pharmacy, Pharmaceutics, 2020
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Development of a low-cost bioprinting system for engineering of Human Tumour Models

  • Authors: Fanucci, Sidne
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/163295 , vital:41026
  • Description: Thesis (MSc)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020.
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Development of a protocol for extracting and quantifying the concentration of thiafentanil in blesbok (Damaliscus pygargus phillipsi) matrices 72-74 hours post administration

  • Authors: Webber, Judith Tracy
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/164738 , vital:41159
  • Description: Thesis (MSc)--Rhodes University, Faculty of Science, Chemistry, 2020
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Development of graphene materials and phthalocyanines for application in dye-sensitized solar cells

  • Authors: Chindeka, Francis
  • Date: 2020
  • Subjects: Dye-sensitized solar cells , Graphene , Phthalocyanines , Molecular orbitals , Impedance spectroscopy
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/166092 , vital:41328
  • Description: Two sets of dye-sensitized solar cells (DSSCs) were fabricated. In the first set, dye-sensitized solar cells (DSSC) were fabricated by incorporating graphene materials as catalysts at the counter electrode. Platinum was also used as a catalyst for comparative purposes. Different phthalocyanines: hydroxyl indium tetracarboxyphenoxy phthalocyanine (1), chloro indium octacarboxy phthalocyanine (2) and dibenzoic acid silicon phthalocyanine (3) were used as dyes. Complex 3 gave the highest power conversion efficiency (η) of 3.19% when using nitrogen doped reduced graphene oxide nanosheets (NrGONS) as a catalyst at the counter electrode, and TiO2 containing rGONS at the anode. The value obtained is close to 3.8% obtained when using Pt catalyst instead of NrGONS at the cathode, thus confirming that NrGONS is a promising candidate to replace the more expensive Pt. The study also shows that placing rGONS on both the anode and cathode improves efficiency. In the second set, DSSCs were fabricated by using 2(3,5-biscarboxyphenoxy), 9(10), 16(17), 23(24)-tri(tertbutyl) phthalocyaninato Cu (4) and Zn (5) complexes as dyes on the ITO-TiO2 photoanodes containing reduced graphene oxide nanosheets (rGONS) or nitrogen-doped rGONS (NrGONS). The evaluation of the assembled DSSCs revealed that using ITO-TiO2-NrGONS-CuPc (4) photoanode had the highest fill factor (FF) and power conversion efficiency (ɳ) of 69 % and 4.36 % respectively. These results show that the asymmetrical phthalocyanine complexes (4) and (5) showed significant improvement on the performance of the DSSC compared to previous work on symmetrical carboxylated phthalocyanines with ɳ = 3.19%.
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Development of manganese phthalocyanine decorated with silver nanoparticles nanocomposite for improved electrocatalytic oxidation of hydrazine:

  • Authors: Mpeta, Lekhetho S , Sen, Pinar , Nyokong, Tebello
  • Date: 2020
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/148472 , vital:38742 , https://doi.org/10.1016/j.jelechem.2020.114173
  • Description: In this study we report on the synthesis of tetrakis [4-(4-(5-chloro-1H-benzo [d]imidazol-2-yl) phenoxy phthalocyaninato] manganese (III) chloride (MnPc). The MnPc was first used to modify a glassy carbon electrode, followed by the growth of silver nanoparticles (AgNPs) onto the MnPc modified electrode to form MnPc-AgNPs modified electrode. The modified electrode was characterized using cydic voltammetry, chronoamperometry, scanning electrochemical microscopy and electrochemical impedance spectroscopy. The modified MnPc-AgNPs electrode was employed for the detection of hydrazine. The MnPc-AgNPs gave better current responses for electrooxidation of hydrazine relative to MnPc and AgNPs, individually. The catalytic rate constant was 1.90 x 10(5 )M(-1) S-1, with the detection limit (LoD) of 2.42 pM (using 3 sigma notation), and sensitivity of 61.56 mu A mM(-1), for MnPc-AgNPs. (C) 2020 Elsevier B.V. All rights reserved.
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Development of paper-based aptasensors for detection of Plasmodium falciparum lactate dehydrogenase in malaria

  • Authors: Ogunmolasuyi, Adewoyin Martin
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/164601 , vital:41147 , doi:10.21504/10962/164601
  • Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biotechnology Innovation Centre, 2020
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Development of phthalocyanine functionalised TiO 2 and ZnO nanofibers for photodegradation of methyl orange

  • Authors: Mapukata, Sivuyisiwe , Nyokong, Tebello
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186323 , vital:44485 , xlink:href="https://doi.org/10.1039/D0NJ03326J"
  • Description: The photocatalytic activity of TiO2 and ZnO based catalysts, which is based on their ability to generate electron–hole pairs upon photoillumination is limited due to their wide band gaps and lack of efficient retrievability post-application. This work reports on the fabrication, characterisation and comparison of electrospun TiO2 and ZnO nanofibers when bare vs when functionalised with a phthalocyanine. The generated photocatalysts are attractive because they absorb visible light and are easily retrievable and hence reusable. With the Pc anchored onto their surfaces, the anatase TiO2 nanofibers and the wurzite ZnO nanofibers possessed singlet oxygen quantum yields of 0.22 and 0.16 in water, respectively. Evaluation of the photocatalytic efficiencies of the nanofibers was conducted by studying the photodegradation of methyl orange. The Pc decorated nanofibers were found to be more effective photocatalysts than the bare ones with the phthalocyanine TiO2 nanofibers being the best. The degradation kinetics were found to follow pseudo first order kinetics and obeyed the Langmuir Hinshelwood model. The nanocatalysts reported herein are therefore feasible candidates for real-life water purification applications.
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Dietary fatty acids of spiders reveal spatial and temporal variations in aquatic-terrestrial linkages

  • Authors: Chari, Lenin D , Richoux, Nicole B , Moyo, Sydney , Villet, Martin H
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/441919 , vital:73935 , https://doi.org/10.1016/j.fooweb.2020.e00152
  • Description: Stream and riparian food webs can be strongly linked by inputs of aquatic emergent insect prey to terrestrial predators. However, quantifying these linkages and understanding how they vary in time and space is challenging. We investigated the dynamic width of a riverine trophic subsidy zone by determining the relationship between perpendicular distance from a river and dietary contributions of aquatic insect prey to web-building spiders' diets. To assess this relationship, riparian web-building spiders at two river sites were sampled during four seasons and analysed for the fatty acids 16:0, 16:1ω7 and 20:5ω3, their total ω3-fatty acid content and their ω3:ω6 ratio to evaluate trophic subsidies reaching them from an adjacent river. River-derived fatty acids generally declined with increased distance from the river, indicating a diffusion of aquatically derived subsidies into the riparian zone. While the river was only 16 m wide at its broadest, river-derived trophic subsidies were detected up to four times that distance from the river edge. Spiders at a downstream section of the river, characterised by generally higher emergence rates of aquatic insects, contained higher proportions of aquatic indicator fatty acids compared with spiders located upstream, where emergence rates were lower. Similarly, proportions of aquatic indicator fatty acids in spiders were lowest during winter when aquatic insect emergence rates were lowest. The fatty acid 20:5ω3 (eicosapentaenoic acid; EPA) held the best promise as a biomarker of aquatic-derived tropic subsidies and could be developed as a useful tool for riparian research and management.
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Digital media marketing and the consumption of sugar-sweetened beverages in Africa: A reception analysis of the multi-channel marketing of Coca-Cola among young Africans from the University of Lagos, Nigeria and Rhodes University, South Africa

  • Authors: Akingbade, Olutobi Elijah
  • Date: 2020
  • Subjects: Carbonated beverages -- Health aspects -- South Africa , Carbonated beverages -- Marketing -- South Africa , Soft drinks -- Health aspects -- South Africa , Soft drinks -- Marketing -- South Africa , Carbonated beverages -- Health aspects -- Nigeria , Carbonated beverages -- Marketing -- Nigeria , Digital media -- Marketing -- Africa , Soft drinks -- Health aspects -- Nigeria , Soft drinks -- Marketing -- Nigeria , Digital media -- Marketing -- Nigeria , Obesity -- Africa , Nutritionally induced diseases -- Africa , Coca-Cola Company -- Marketing , Rhodes University -- Students -- Attitudes , University of Lagos -- Students -- Attitudes
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/163125 , vital:41012
  • Description: This study investigates and examines how Coca-Cola’s marketing communications, especially the newer forms of digital, social and mobile media marketing messages/campaigns, are received, understood and made sense of by two sets of purposefully selected young urban African students in Nigeria and South Africa. Embedded within a qualitative research design and underpinned by an interpretative phenomenological analysis (IPA) approach, this study was conducted against the backdrop of the recent surge in the consumption of Sugar Sweetened Beverages (SSBs) which has been directly implicated in the rise of obesity and a variety of non-communicable diseases (NCDs) in Africa. The thesis explores the role of multinational SSBs in this surge, as African countries have become key focus areas for multinational food and beverage companies seeking growth and profits, as home markets decline partly due to better health communications and, in some cases, the implementation of so-called ‘sugar taxes’ and the attendant negative publicity around these taxes. The focus on young Africans from Nigeria and South Africa was motivated by the similar rapid urbanisations in both countries, often accompanied by changes in diet and greater consumption of fast foods and SSBS, and by South Africa’s ranking as the country with the highest prevalence of overweight persons and obesity in Sub-Saharan Africa. Similar rises in national average weights are now also starting to be seen in Nigeria, as are surges of diet-related disease incidence and prevalence. The study is informed by Consumer Culture Theory (CCT) but also draws on other theories and some key concepts from marketing studies, health science and psychology. Methodologically, the study draws on in-person observations, focus group interviews and semi-structured individual in-depth interviews, to explore how Coca-Cola has created a deep and evocative historical ‘brandscape’ and how it has become a multicultural resource in both South Africa and Nigeria. Through an investigation into the lived experiences of study participants with regards to both their earliest and more recent engagements with Coca-Cola, as a brand and as a product, the study delineates the influence of older generations of Coke enthusiasts and consumers within participants’ households and newer spaces of interaction with Coke via interactive, highly personalised social media-centric campaigns. This study explores how the ubiquitous nature of Coca-Cola’s aesthetics and signage are engaged with – often in very ‘sub-conscious’ ways – by these students and how more recent social media campaigns evoke this multigenerational history. Unpacking study participants’ self-understandings of Coke and their often ‘sub-conscious’ engagements with the SSB, this study explicates the underpinning ideological grounding and how this is sustained over time to become an hegemonic code that does not only confine participants’ engagements with SSBs to Coke but also confines their reception of, and engagements with, Coke’s media marketing messages/campaigns to those that resonate with the multigenerational history evoked by the SSB. It is within this contextual background that this study brings to the fore participants ‘cognitive dissonance’ and scepticism and often rank disbelief of the health risks posed by their high levels of Coke consumption. The study concludes that attempts to raise awareness about the dangers inherent in excessive consumption of SSBs in Africa need to be reviewed and rethought. There is a need for long-term, consistent and much more proactive health journalism, alongside public health campaigns in both official and indigenous languages, to dispel the powerful myths created by SSB marketing and explain how SSBs are implicated in the rise of diet-related NCDs in Nigeria and South Africa.
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Dimensions and indicators of non-profit financial condition: evidence from South African public universities

  • Authors: Bunting, Mark B
  • Date: 2020
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/150296 , vital:38965 , DOI: https://doi.org/10.4102/sajems.v23i1.2974
  • Description: More than three decades of research have failed to achieve convergence on a method for the measurement of non-profit financial condition, with the literature reporting a bewildering array of financial dimensions, and more than 100 ratios and indicators. This article offers a contribution to a broader discourse in non-profit financial analysis by recognising, and taking action in response to, the potential threat to research validity arising from the generally unchallenged presumption that accounting numbers provide a complete, unbiased and error-free representation of an entity’s underlying economic reality.
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Direct nonlinear optical absorption measurements of asymmetrical zinc (II) phthalocyanine when covalently linked to semiconductor quantum dots

  • Authors: Mgidlana, Sithi , Sen, Pinar , Nyokong, Tebello
  • Date: 2020
  • Subjects: To be catalogued
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/186056 , vital:44459 , xlink:href="https://doi.org/10.1016/j.molstruc.2020.128729"
  • Description: We report on nonlinear optical properties of tris[(4-tert-butyl)-2-thio (phenyl)acetic acid (1) and tris(dimethyl-5-(3,4-phenoxy) isophthalate (2) phthalocyaninato zinc (II) complexes. The synthesized complexes were covalently conjugated to glutathione-capped CdTe/ZnSe/ZnO quantum dots. We observed an increase in triplet quantum yield with corresponding decrease in fluorescence quantum yield of conjugates compared to Pc complexes alone. Z-scan technique was employed to experimentally test the nonlinear optical response of complexes and nanoconjugates in solution at laser excitation wavelength of 532 nm with 7 ns pulse. Nonlinear absorption coefficient, third-order optical susceptibility and optical limiting threshold of the materials were obtained from the Z-scan data. The nonlinear absorption parameters improved in the presence of CdTe/ZnSe/ZnO, with 1 and 1-CdTe/ZnSe/ZnO, giving the best results due to the presence of electron donating substituents.
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Disco

Discursive constructions of alcohol use and pregnancy among participants in intervention aimed at reducing Foetal Alcohol Spectrum Disorders

  • Authors: Msomi, Nqobile Nomonde
  • Date: 2020
  • Subjects: Fetal alcohol spectrum disorders -- South Africa , Pregnancy -- Psychological aspects , Reproductive rights -- South Africa , Reproductive health -- South Africa
  • Language: English
  • Type: text , Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/140374 , vital:37883
  • Description: South Africa’s socio-cultural and political history has had significant effects on maternal and reproductive health. The hazardous alcohol use patterns in the country have affected alcohol consumption during pregnancy. Antenatal exposure to alcohol may result in Foetal Alcohol Spectrum Disorders (FASD). The levels of FASD in particular areas of the country are the highest recorded in the world. Epidemiological studies have dominated pregnancy and FASD research in South Africa; however, recently critical scholarship seeking to contextualise the issue of drinking alcohol during pregnancy is emerging. This study forms part of a developmental/formative assessment of an alcohol and pregnancy intervention. Assessment is an important part of pilot interventions, and discourse is a key area of focus due to its constitutive role for the subjectivity of human beings and legitimation of institutional practices. Using a reproductive justice perspective and a Foucauldian approach to analysis, I identified five prominent discursive constructions of alcohol use during pregnancy produced during interviews with community educators. These interviews were conducted following training workshops with the community educators. Participants constructed their living environments as ‘wholly bad’ and ‘issue-ridden’ and positioned alcohol consumption as ‘a destroyer!’, ‘king’ and a social lubricant. They interpellated the foetus, the ‘FASD child’ and pregnant women into this context. They positioned themselves as transformed subjects able to effect change. The foetus was constructed as ‘vulnerable and important’, as opposed to the ‘defiled FASD child’. Pregnant women were constructed as ‘ignorant, preoccupied and unreceptive to knowledge’. These constructions hinged on so-called ‘scientific knowledge’ of biological processes in utero, demonstrating Foucault’s conception of the power/knowledge nexus and how its dynamics transforms knowledge of human beings. Whereas this ‘knowledge’ transformed alcohol consumption and the foetus into powerful and vulnerable subjects respectively, the circulating discourses had objectivising effects on pregnant women. The discourses of responsibilisation, the personification of the foetus, ‘the problem’ category of FASD, the discourse of difference, and the discourse of alcohol consumption as an entrenched practice were circulating around pregnant women. I suggest alterations to the identified constructions using principles of community psychology, the harm reduction model, a social model of disability and the reproductive justice perspective
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Distribution, habitat associations and conservation of the Eastern Cape rocky Sandelia bainsii (Perciform: Anabantidae) in the Great Fish River system

  • Authors: Sifundza, Delsy Sindy
  • Date: 2020
  • Subjects: Anabantidae -- South Africa -- Great Fish River , Perciformes -- South Africa -- Great Fish River , Labyrinth fishes -- South Africa -- Great Fish River , Fishes -- Effect of human beings on -- South Africa -- Great Fish River , Fish populations -- South Africa -- Great Fish River , Fish declines -- South Africa -- Great Fish River , Fish populations -- Monitoring -- South Africa -- Great Fish River , Anabantidae -- Evolution -- South Africa -- Great Fish River , Gene flow , Mitochondrial DNA , Microsatellites (Genetics) , Eastern Cape rocky Sandelia bainsii , Freshwater ecology -- South Africa -- Great Fish River
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/142692 , vital:38102
  • Description: In South Africa, freshwater ecosystems are under pressure due to increasing anthropogenic factors degrading river systems. The Cape Fold, the lower Southern Temperate Highveld and the Amatolo – Winterberg Highlands freshwater ecoregions contain some of the heavily impacted river systems in the country. One such river system is the Great Fish River system, which has been affected by anthropogenic modification (hydrological modification, water pollution and invasion by non-native fish species). These modifications have raised conservation concerns on an imperilled anabantid fish, the Eastern Cape rocky Sandelia bainsii that is confined to the Kat and Koonap rivers, which are tributaries of the Great Fish River. Historically, the species was reportedly common and abundant, with a range spanning across seven river systems (Kowie, Great Fish, Keiskamma, Igoda, Gxulu, Buffalo and Nahoon rivers) in the Eastern Cape Province. However, surveys have indicated that the species has experienced decline in population size and distribution range, with localised extirpations being reported. This resulted in its listing on the IUCN Red List of threatened species as Endangered. The proposed shale gas exploration and potential infrastructure development in the Karoo basin, which encompasses the headwaters of the Kat River, represent a potential future threat to the remnant populations of this species. The aim of the present study was to review the past and present distribution range of S. bainsii, determine the habitat associations and assess the conservation of S. bainsii in the Great Fish River system. This information is essential for informing conservation and management decisions for this species in the Great Fish River system. This study undertook a comprehensive survey of the Kat and the Koonap rivers in 2017, and augmented this information with data from more recent surveys that were conducted from 2009 - 2014 to map the distributions freshwater fishes in the Great Fish River system. Data from these recent surveys (2009 – 2017) were compared with historical records (1961 – 2005) obtained from the South African Institute for Aquatic Biodiversity to evaluate changes in distribution patterns of S. bainsii. Historical records indicated that S. bainsii occurred at 11 localities in the Kat River and three localities in the Koonap River. Data from recent surveys indicated that the species has persisted at these historical localities, except one locality in the Koonap River where no individuals of S. bainsii were captured, despite the use of multiple sampling approaches and gears. Although the species still persists at two of the three historical localities in the Koonap River, the population sizes have considerably declined as the species was reportedly in high abundance at these localities in the 1980s. Factors threatening the continued existence of this species in the Koonap River likely include non-native species, extreme drought conditions and the associated excessive abstraction of water which has resulted in the drying of some of the refugia pools where the species was historically common and abundant. In contrast to the Koonap River, the 2017 survey indicated that in the Kat River, S. bainsii had a similar distribution range compared to historical records. The species occurred at 11 of the 41 localities that were sampled in the Kat River, and the sampled populations consisted of all size classes. Sandelia bainsii occurred with other native fish species in the system, including Labeo umbratus, Enteromius anoplus and Glossogobius callidus. A comparison of historical and recent data indicates that non-native fishes have likely not expanded their ranges in the Kat River. This is likely due to the presence of weirs and dams that have prevented upstream movement of non-native fish species L. aeneus, C. gariepinus and T. sparrmanii which are now abundant in the lower Kat and mainstem Great Fish River. Surveys from the present study indicated that although S. bainsii still persists within the Kat River, there are a number of factors that pose a considerable threat to the continued existence of this species in the Great Fish River system. Chapter 3 evaluated the habitat associations of S. bainsii based on 10 physical and chemical variables and distribution data collected from 30 localities in the Upper Kat River and seven of its tributaries. A non-metric multidimensional scaling model was used to assess the distribution patterns of S. bainsii in relation to environmental variables. Furthermore, a negative binomial generalised linear model (GLM) was used to assess the relationship between the abundance of S. bainsii and environmental variables. Results from the present study indicated that S. bainsii was a habitat generalist as the distribution of this species showed no specific association with any of the habitat variables that were considered in this study. The species occurred in a wide range of habitats, including rocky sections in the upper Kat River and its tributaries as well as the mainstem sections. The GLM however indicated that the abundance of S. bainsii was negatively associated with increasing conductivity. In addition, the Kat River contains multiple weirs of variable sizes. Future studies should therefore evaluate the effects of these weirs on population fragmentation, gene flow and long-term evolutionary potential of S. bainsii through the application of techniques such as mitochondrial DNA and microsatellites.
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Diteng tsa ditlhopha tsa maina a Bantu: ntlhathakanelo e le mo Setswanang : “The semantics of Bandu noun classes: a focus on Setswana

  • Authors: Tladi, Oboitshepo
  • Date: 2020
  • Subjects: Tswana language , Tswana language -- Grammar , Tswana language -- Noun , Noun , Bantu languages , Bantu languages -- Noun , Bantu languages -- Grammar
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: http://hdl.handle.net/10962/167654 , vital:41500
  • Description: The present study investigated the semantic classification of the Setswana noun class system. This enquiry falls under the broad area of the noun classification system in Bantu languages, psycholinguistics and lexicogrpahy. Specifically it explores the basis of noun classification in Setswana making indications that Setswana noun classification is based on a partial semantic classification. Data for the study was drawn from the Setswana Oxford Dictionary. Sixty Setswana nouns, from class 1, 3, 5, and 7, were selected and analysed and then grouped into semantic categories (i.e., PERSON, DEROGATION, TRANSPORATION and so forth). The study adopted Kgukutli’s (1994) semantic classification in performing the dictionary analysis. The rest of the data was drawn from the intuitions of thirty-nine contemporary speakers of Setswana, with the aid of a linguistic test which was fashioned according to Selvik’s (2001) psycholinguistic test. The language test required participants to match the predetermined Setswana definitions with hypothetical Setswana nouns with selected class prefixes attached to them. The results from the empirical study showed that speakers were associating prefixes to certain semantic values, suggesting that each noun class had specific semantic content that was unique to that class. The semantic categories created through the dictionary analysis were then compared to those given by the thirty-nine Setswana speakers, to analyse whether there were any similaritires in the semantic classification of the noun classes. The findings of the dictionary analysis and linguistic test revealed that there were certain semantic characteristics that each class was associated with that seemed to be unique to the class. However, there were various semantic overlaps in the semantic categories associated with the different noun classes, which brings into question whether a semantic classification is viable in the classing of nouns. The study suggests that prior classification of Setswana nouns are not precise enough and that additional semantic categories are needed to offer a more precise classification of nouns in this language.
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Do spotted hyaenas outcompete the big cats in a small, enclosed system in South Africa?:

  • Authors: Comley, J , Joubert, C J , Mgqatsa, Nokubonga , Parker, Daniel M
  • Date: 2020
  • Language: English
  • Type: text , article
  • Identifier: http://hdl.handle.net/10962/150099 , vital:38940 , doi:10.1111/jzo.12772
  • Description: Carnivores are adapted to kill, meaning sympatric carnivores can have particularly aggressive and harmful competitive interactions. The co‐existence of multiple carnivores in an ecosystem could be restricted by their similarity in ecological niches (e.g. dietary overlap); however, high prey abundances could facilitate their co‐existence. Although the development of small, enclosed reserves (over 400 km2) in South Africa has reduced human–carnivore conflict, these systems may increase the likelihood of carnivore intra‐guild competition due to the clumping of competing carnivores into these restricted spaces. Using carnivore scat and kill site analyses, we determined the dietary preferences and overlap of sympatric large carnivores in a small, enclosed reserve, Selati Game Reserve (Selati).
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Do submarine canyons influence the structure and diversity of benthic fish assemblages on the continental shelf edge?

  • Authors: Nyawo, Mpilonhle Aura June-Rose
  • Date: 2020
  • Subjects: Submarine valleys , iSimangaliso Wetland Park (South Africa) , Biotic communities -- South Africa -- iSimangaliso Wetland Park , Groundfishes -- South Africa -- iSimangaliso Wetland Park , Marine ecology -- South Africa -- iSimangaliso Wetland Park
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/167264 , vital:41462
  • Description: Marine ecosystems play an important role in human welfare, such as providing food security and providing social, economic and environmental benefits to an increasing human population. However, due to the deleterious impact of overfishing as well as habitat degradation, pollution and climate change, many marine ecosystems and the substantial biodiversity they support, are under increasing threats. Submarine canyon ecosystems cut into the continental margin in all our oceans and are considered regions of enhanced diversity, abundance and biomass for many marine communities, including fish. In South Africa, the tropical Delagoa Ecoregion is characterised by numerous submarine canyons that are home to coelacanths Latimeria chalumnae, and a variety of commercially important line fish species. However, there is currently a lack of information on the ecological structure and functioning of these canyons, in relation to nearby non-canyon ecosystems. The aim of this thesis was to generate knowledge on the role of submarine canyons in influencing the benthic fish assemblage structure and diversity on the continental shelf and shelf edge within the high-latitude coral reef ecosystems in the tropical Delagoa Ecoregion of South Africa. First, a systematic literature review was conducted to examine the current knowledge on the role of submarine canyons on the benthic fish assemblages occurring on continental margins, as well as outline the trends in canyon research. For the fieldwork component of this thesis, baited remote underwater stereo-video systems were utilised to gather data. The first research chapter, chapter 3, investigated the effect of ecosystem and depth on the diversity and structure of benthic fish assemblages within iSimangaliso Wetland Park in the Delagoa Ecoregion. Data were collected in 2017 from Wright Canyon (canyon ecosystem) and adjacent slope ecosystems around the canyon (non-canyon ecosystem) at depths ranging between 70–240 m. The second research chapter, chapter 4, data were collected in 2018, from 60–100 m depths in three ubmarine canyons (Wright, Diepgat,Levens) and their adjacent habitat within iSimangaliso Wetland Park to investigate the diversity patterns and community structure of benthic fish and cons ider location as a factor. The systematic review showed that canyon research is still very much in its infancy, however more papers are expected to be published in the future. There were clear location associated biases detected, with more than 90% of the canyon research being concentrated in the Mediterranean Sea, while only one study was published from South Africa. Most of the reviewed literature focused on invertebrates, with benthic fish (including cartilaginous fish) being the second most studied taxa. A wide range of methods from both fishery- dependent and fishery-independent categories were used to gather the data of benthic fish from the canyons and adjacent areas. With over 8500 submarine canyons mapped globally, the number of submarine canyon research published and the detected location bias is of great concern. More studies are needed in order to understand the role of submarine canyons on adjacent slope habitats Overall, the results from the research chapters indicated that there were higher a bundances in the canyon ecosystem compared to the non-canyon ecosystem. In contrast, evenness and beta-diversity were higher in the non-canyon ecosystem. Relief, bottom type as well as depth played a major role in explaining the observed abundance and diversity patterns. Both evenness and beta-diversity decreased with increase in depth. The canyon and non-canyon also differed in terms of habitat structure. The canyon ecosystem was characterised by patched reef and reef habitats with high relief whereas the non-canyon ecosystem was characterised by flats and habitats, especially at shallower depths. Additionally, there were clear differences in terms of the fish community structure between the canyon and the non-canyon ecosystem. The heterogeneous and complex habitats of the canyon ecosystem were typified by species such as Epinephelus poecilonotus, Polysteganus coeruleopunctatus and Chrysoblephus puniceus in comparison to the less complex habitats outside the canyons that were preferred by species such as Lagocephalus sceleratus, and Rhinobatos leucospilus. The different locations sampled demonstrated that the canyon effect was not onsistent at all locations, with varying results detected in the different sample locations. This research demonstrates that clea r differences exists between the benthic fish assemblages associated with canyon and non-canyon ecosystems and provides important information on the role of submarine canyons in the iSimangaliso Wetland Park. From this thesis, it is clear that a ‘canyon effect’ exists in the continental shelf and shelf edge. The results suggested that heterogeneity of habitats was the most important environmental factor that differed between the canyon and non-canyon ecosystems and these differences in the habitat were driving the observed patterns. This thesis has provided a reference point, with regards to investigating the role and influence of these canyons on benthic fish assemblages occurring on the continental shelf edge. The information provided by this thesis can ultimately be used in other studies investigating benthic fish assemblages in other submarine canyons within iSimangaliso Wetland Park and the rest of South Africa./
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