Synthesis, spectroscopic and nonlinear optical properties of asymmetric A3B type phthalocyanine complexes
- Authors: Mugeza, Rhulani Donney
- Date: 2021
- Subjects: Spectrum analysis , Mass spectrometry , Phthalocyanines
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/171667 , vital:42108
- Description: This work reports on the synthesis of symmetrical and asymmetrical A 3 B type metal free, cobalt and zinc Phthalocyanines (Pc) .A wide range of spectroscopic techniques such as Uv - visible absorption (UV), magnetic circular dichroism (MCD), mass spectrometry, elemental analysis, IR spectroscopy and time correlated single photo n counting spectroscopy (TCSPC) have been used to study the spectroscopic properties of the phthalocyanine complexes. The Z - scan technique was used to comparatively investigate the nonlinear absorption coefficient ( 휷 ) and the nonlinear refraction index ( 풏 ퟐ ) of the synthesized complexes. The following trend was obtained for the synthesized Pc’s in terms of the 휷 values 7.25 × 10 − 10 ( 4b ) > 3.76 × 10 − 10 ( 4a ) > 3.52 × 10 − 10 ( 4c ) > 2.29 × 10 − 10 ( 3c ) > 1.68 × 10 − 10 ( 3a ) > 1.65 × 10 − 10 ( 3b ) mW - 1 . The 휷 values trend of synthesized Pc complexes show that the asymmetrical A 3 B type metal free, cobalt and zinc Pc complexes ( 4a , 4b and 4c ) have larger 휷 values as compared to the octa - substituted symmetrical metal free, cobalt and zinc Pc complexes ( 3a , 3b and 3c ) which is attributed to the low symmetry of the Pc complexes. The five - level model rate equations were used to determine the two photon absorption, excited state absorption and ground state absorption cross sections of the synthesized complexes. The z inc A 3 B type asymmetrical Pc complexes gave the largest two photon absorption and 휎 푒 / 휎 푔 ratio values. This Pc complex could be used in future work to enhance the nonlinear response further by introducing nanomaterials and converting the Pc complex to a binuclear Pc. This work also reports on the density functional theory (DFT) calculations o f dipolar/octupolar contributions in order to study the first order hyperpolarizability of the synthesized Pc complexes.
- Full Text:
- Date Issued: 2021
The changing nature of work: understanding precarity and the gendered individualisation of risk in post-apartheid South Africa
- Authors: Mhlana, Siviwe
- Date: 2021
- Subjects: Precarious employment , Labor supply -- South Africa , Labor supply -- Statistics -- South Africa , Precarious employment -- South Africa , Informal sector (Economics) -- Employees -- South Africa , Women employees -- South Africa , Women temporary employees -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/172146 , vital:42170
- Description: Against the backdrop of workplace restructuring globally, post-Apartheid South Africa is experiencing consistently high levels of unemployment, the deterioration of employment security, and limited improvements in earnings. This trend in the proliferation of low-paid, unstable and otherwise insecure employment has given rise to a segment of the literature that is centred on the growing precariousness of work in a number of different contexts. This thesis reviews empirical work on the changing nature of labour-intensive production in the past two decades, with particular focus on the trends in non-standard, informal and precarious employment. Further, the thesis examines the shift in the gender structure of South Africa’s manufacturing sector and how it affects the share in the benefits of employment, particularly with regard to social reproduction. In so doing, the thesis expands the critical theoretical narrative about the challenges of labour under neoliberalism by providing an intersectional perspective of precarious work in post- Apartheid South Africa.
- Full Text:
- Date Issued: 2021
A sociological analysis of the sex education of young adult white womxn and their understandings and practices of ‘Safe Sex’
- Authors: Guerra, Cassandra Gadelha
- Date: 2020
- Subjects: Sex instruction , Sex instruction for girls , Women, White -- Psychology , Women, White -- Sexual behavior
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/147267 , vital:38610
- Description: This research sets out to examine the experiences and perspectives of young adult white womxn regarding their respective sex education. This is in terms of how sex education may shape and influence sexual practices. The relevance of exploring the sex education of this group is to gain an understanding of how constructions of sex education may facilitate the negotiation of sexual practices, particularly as these practices relate to the negotiation of ‘safe sex’. This involves an exploration of definitions of ‘safe sex’ as well as an examination of the various sources of sex education. This research argues that sex education has been socially constructed within a ‘heterosexual matrix’ where both gender identities and sexuality are constructed in heterosexual terms in accordance with compulsory heterosexuality. Furthermore, that sex education as well as understandings and practices of ‘safe sex’ intersect with other social categories such as race, gender and sexuality. Much of the sex-related research conducted in South Africa focuses on people of colour, as a result very little is known about the sexual behaviours and practices of the white demographic. This research accounts for the absence of analysis of sexual practices and behaviour among white people by examining the sex education and sexual practices of young adult white womxn between the ages of 19 and 24. The research observed key sources of sex education which included parents, schools, religious institutions and the internet. Findings indicate that the sex education of participants reflected ideals of heteronormativity and misogyny which were found to directly influence their understandings and practices of both sex and ‘safe sex’. Furthermore, that the sex education participants received has ultimately failed to promote ‘safe’ sexual practices.
- Full Text:
- Date Issued: 2020
Age of squid Loligo reynaudii d’Orbigny, 1845, and its possible use to test effectiveness of the closed season in protecting this resource
- Authors: Mwanangombe, Collette Habani
- Date: 2020
- Subjects: Loliginidae -- Spawning -- South Africa , Loliginidae -- Age determination , Loligo fisheries -- South Africa , Fishery management -- South Africa , Otoliths , Loliginidae – Eggs -- Incubation , Loliginidae – Growth , Fish stock assessment -- South Africa , Recruitment (Population biology) -- South Africa , Loligo reynaudii d’Orbigny
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144333 , vital:38336
- Description: This study presents age distributions representing populations of adult Loligo reynaudii, together with the results of spawning and commercial catches to assist in understanding the beneficial role of the closed season. The results were based on 791 samples collected during three closed seasons (November: 2003, 2004 and 2005) and out of closed season during April/May 2005. Age and predicted growth were examined by counting daily rings on statolith microstructures. The age in days after hatching ranged from 168 to 484 days (71-425 mm) in males and from 125 to 478 days (83-263 mm) in females. Average age at spawning was found to be 323 days in males and 316 days in females. Population estimates of growth rates were best described by a linear growth model which revealed that males grew faster than females in length as they grew older with growth rate ranging between 0.63 to 0.83 mm per day for males and between 0.22 to 0.32 mm per day for females. Back-calculated hatch dates and later egg-laying events for parental populations were determined. Results from back calculated egg laying dates (presented as percentage of frequency of all laying dates) indicated a highest total of 36%, 39% and 15% of eggs from all samples were laid during the closed season and nine days after the closed season during year 2003, 2004 and 2005 respectively. Monthly commercial total catches (2002-2005) showed an increase from November soon after the fishery resumed, up until the month of January. Daily catches were highest in November (up to 290 tonnes) relative to the daily catches observed in December and January in all the years. Results led to the conclusion that the closed season (25 October to 22 November) is beneficial for both the chokka resource and the fishery. This is because: a) there is time for enough spawning biomass to accumulate, which subsequently results in high catches (good fishery), in the current year, best immediately after season opens in November; b) there is a link in the results between egg laying dates in the period of closed season and immediately afterwards, and the magnitude of catches in last nine days of November.
- Full Text:
- Date Issued: 2020
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.
- Full Text:
- Date Issued: 2020
Photo-physicochemical characterization and in vitro Photodynamic Therapy Activity of Phthalocyanine-Graphene Quantum Dots Conjugates
- Authors: Nene, Lindokuhle Cindy
- Date: 2020
- Subjects: Photochemotherapy , Cancer -- Chemotherapy , Quantum dots , Graphene , Nanomedicine
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/140463 , vital:37891
- Description: This thesis reports on the preparation of several differently substituted Zn(II) phthalocyanine (Pc) complexes and their respective graphene quantum dots (GQDs) conjugates. In addition, Pc complexes substituted with biologically active molecules used in cancer therapeutics, namely: benzothiazole and morpholine, were also prepared and conjugated to GQDs. The photo-physicochemical properties were determined for both the complexes and their respective conjugates including the fluorescence/ triplet quantum yields and lifetimes as well as the singlet oxygen generating abilities. Upon conjugation to GQDs, the fluorescence of the Pc complexes decreased (insignificant decrease in some cases), with an increase in the triplet quantum yields. However, the singlet quantum yields of the Pcs in the conjugates did not show an increase with the increase in the triplet quantum yields. This is suspected to be due to the screening effect. The cytotoxicity of the complexes in vitro decreased upon conjugation, as a result of reduced actual number of Pc units provided in the conjugate for therapy. An increase in the efficacy upon quaternization was observed, and a relatively better performance was also observed for the cationic complex in combination with the biotin- functionalized GQDs, 7-GQDs-Biotin. Moreover, the cellular uptake of 7-GQDs-Biotin over 24 h was relatively high compared to complexes alone and other Pcs-GQDs conjugates.
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- Date Issued: 2020
“Ntombazana, ugayela bani?”: ubunzululwazi beentsimbi
- Authors: Silo, Tolakele Talitha
- Date: 2020
- Subjects: Beadwork, Xhosa , Xhosa (African people) -- Social life and customs , Beadwork, Tembu , Tembu (African people) -- Social life and customs
- Language: Xhosa
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/167487 , vital:41485
- Description: “ NTOMBAZANA, UGAYELA BANI?”: UBUNZULULWAZI BEENTSIMBI is a study on the culture of abaThembu, one of the amaXhosa subgroups. Focusing on beadwork as one of this group’s cultural aspects, this research is an initiative to ensure documentation of such indigenous knowledge as an influence on the lifestyle of abaThembu. It also strives to uplift the use of oral literature to present it a fair chance at being a driving force for change as it has previously been ousted with the acceptability of written literature. Of great surprise is to see that despite western civilization, which affected the people’s culture, beadwork remains a pillar of the abaThembu-amaXhosa culture. This craft has evolved and thus, shows no signs of regression. This thesis is an indigenous knowledge focused research.
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- Date Issued: 2020
Reproductive isolation mechanisms of two cryptic species of Eccritotarsus (Hemiptera: Miridae), biological control agents of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae)
- Authors: Mnguni, Sandiso
- Date: 2019
- Subjects: Eccritotarsus , Meridae , Noxious weeds -- Biological control -- South Africa , Aquatic weeds -- Biological control -- South Africa , Water hyacinth -- Biological control -- South Africa , Biological pest control agents
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/68133 , vital:29202
- Description: Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae), is one of the world’s worst alien invasive plants. It is indigenous to the Amazon basin in South America but has become a problematic alien invasive in other parts of the world. As such, several host-specific biological control agents have been sourced from the native distributions in South America and have been released to control this plant where it has become problematic. Two of these agents include the geographically and reproductively isolated cryptic species of Eccritotarsus (Hemiptera: Miridae). One of these species was collected in the upper reaches of the Amazon River in Peru, while the other was collected over 3500km away from that site, in Florianopolis, southern Brazil. These cryptic species were thought to be a single species until recently, when DNA barcoding indicated that they were likely to be two species, and the species status has now been confirmed by interbreeding experiments and detailed morphological studies. The Brazilian population remains Eccritotarsus catarinensis (Carvalho), while the Peruvian population is now known as Eccritotarsus eichhorniae (Henry). The aim of this project was to investigate the mating behaviour and other behavioural traits of the two species that have resulted in reproductive isolation, and which could have led to speciation. In addition, investigations involving analysis of chemical compound compositions of the two species aimed to determine the extent to which the compounds played a role in the development and maintenance of reproductive isolation. To achieve the aims, behavioural-observation experiments were conducted in the form of no-choice, bi-choice and multi-choice tests in 1:1, 2:1 and 3:1 sex ratio assessments, both within and between species. Chemical compound compositions of E. catarinensis and E. eichhorniae were also assessed using Nuclear Magnetic Resonance (NMR), Solid-phase micro-extraction (SPME) and Gas-Chromatography Mass-Spectrometry (GC-MS) techniques. In no-choice experiments, the highest number of single and multiple copula incidences, and average total copula duration was found within species while copulation between species was much rarer. In bi-choice experiments, E. eichhorniae females and E. catarinensis males only chose to mate with their respective conspecifics, and within species copulations continued to have higher average total copula duration. In multi-choice experiments, the highest number of single and multiple copula incidences and average total copula duration was also found within species. GC-MS analysis suggested that E. catarinensis females and E. eichhorniae males have unique chemical compounds missing in their conspecifics and same sex of the other species. Further analysis suggested that E. catarinensis females and E. eichhorniae males have similar chemical compound compositions, whereas as E. eichhorniae females and E. catarinensis males have similar chemical compound compositions. These results suggest that there are behavioural differences that led to the development and maintenance of prezygotic reproductive isolation mechanisms, and that this is probably driven by pheromones in chemical compound compositions. These two species were geographically isolated in the native range and the populations have diverged to the point that they are now reproductively incompatible and therefore, distinct species. The main driver of the speciation is most likely mate recognition and attraction, as only reproductively important traits such as pheromones, genitalia, the scent glands and antennae have changed, while other traits, including host range and morphology, have remained remarkably stable. This provides evidence that differences in sexual selection in isolated populations may be important drivers of speciation and reproductive isolation in cryptic species.
- Full Text:
- Date Issued: 2019
Synthesis of indium phthalocyanines for photodynamic antimicrobial chemotherapy and photo-oxidation of pollutants
- Authors: Sindelo, Azole
- Date: 2019
- Subjects: Phthalocyanines , Azo dyes , Indium compounds , Photochemotherapy , Nanoparticles , Photodegradation , Pollutants , Water -- Purification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67581 , vital:29116
- Description: Indium (III) octacarboxyl phthalocyanine (ClInOCPc) alone and when conjugated to magnetic nanoparticles (MNP-ClInOCPc), 2(3),9(10),16(17),23(24)-octapyridylsulfanyl phthalocyaninato chloroindium (III) (ClInOPyPc) and its quaternized derivative 2(3),9(10),16(17),23(24)-octamethylpyridylsulfanyl phthalocyaninato chloroindium (III) (ClInOMePyPc) were synthesized. All Pcs were tested for both photodynamic antimicrobial chemotherapy (PACT) of an unknown water sample and photo-degradation of methyl red (MR). The singlet quantum yield (ΦΔ) for the ClInOCPc and MNP-ClInOCPc in PAN polymer fibers were 0.36 and 0.20 respectively using ADMA as a quencher in water. The photo-inactivation of bacteria in a water sample with unknown microbes was tested, with the MNP-ClInOCPc inactivating 90.6 % of the microbes and the ClInOCPc with 84.8 %. When embedded to the polymer, there was 48% bacterial clearance for ClInOCPc and 64% clearance for the MNP-ClInOCPc. The rate of degradation of MR increased with decrease of the MR concentration, with the MNP-ClInOCPc having the fastest rate. For ClInOPyPc and ClInOMePyPc, the singlet quantum yields were 0.46 and 0.33 in dimethylformamide (DMF), respectively. The PACT activity of ClInOMePyPc (containing 8 positive charges) was compared to those of 9(10),16(17),23(24)-tri-N-methyl-4-pyridylsulfanyl-2(3)-(4-aminophenoxy) phthalocyaninato chloro indium (III) triiodide (1) (containing 3 positive charges) and 2-[4-(N-methylpyridyloxy) phthalocyaninato] chloroindium (III) iodide (2) (containing 4 positive charges). When comparing ClInOMePyPc, 1 and 2, the largest log reduction for E. coli were obtained for complex 2 containing four positive charges hence showing it is not always the charge that determines the PACT activity, but the bridging atom in the phthalocyanine plays a role.
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- Date Issued: 2019
A comparative study of tax incentives for small businesses and investors in small businesses in South Africa, Australia, New Zealand, Singapore and Ireland
- Authors: Horn, Edward Bennet
- Date: 2018
- Subjects: Small business -- Taxation -- South Africa , Small business -- South Africa -- Finance , Job creation -- South Africa , Government aid to small business -- South Africa , Tax incentives -- South Africa , Tax incentives -- Australia , Tax incentives -- New Zealand , Tax incentives -- Singapore , Tax incentives -- Ireland
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/61669 , vital:28047
- Description: In the South African context, it is accepted that small businesses will be the vehicle for job creation and changing the current business ownership patterns. This is to be achieved by creating access to finance, exploring the role of venture capital and simplifying the tax obligations and the compliance burden. The literature indicates that the current South African tax incentives for small businesses are perceived as unfair and fundamentally ineffective. The objective of this thesis was to compare the tax incentives available to small businesses and investors in small businesses in South Africa to those available in Australia, New Zealand, Singapore and Ireland, in order to identify possible measures that could be introduced in South Africa. In addressing the objective, the research set out to provide, in terms of South African tax legislation, a definition of a small business for tax purposes and document the tax incentives available for start-up and existing small businesses, as well as the tax incentives available for investors in small businesses, either through a venture capital company or a direct investment in small business. It was found that South Africa has a complex and onerous multi-layered approach to classifying a taxpayer as either a “micro business” or a “small business corporation” for the purpose of applying tax incentives. The international jurisdictions included in this research follow a single requirement approach, based on either one or a combination of turnover, balance sheet total or staff headcount. The international jurisdictions provide a wide range of tax incentives to small businesses and investors in small businesses, aimed at reducing taxable income to enable the small businesses to grow and access equity finance. By identifying differences and similarities, a number of possible tax relief measures were recommended that could be introduced in South Africa.
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- Date Issued: 2018
Advanced radio interferometric simulation and data reduction techniques
- Authors: Makhathini, Sphesihle
- Date: 2018
- Subjects: Interferometry , Radio interferometers , Algorithms , Radio telescopes , Square Kilometre Array (Project) , Very Large Array (Observatory : N.M.) , Radio astronomy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/57348 , vital:26875
- Description: This work shows how legacy and novel radio Interferometry software packages and algorithms can be combined to produce high-quality reductions from modern telescopes, as well as end-to-end simulations for upcoming instruments such as the Square Kilometre Array (SKA) and its pathfinders. We first use a MeqTrees based simulations framework to quantify how artefacts due to direction-dependent effects accumulate with time, and the consequences of this accumulation when observing the same field multiple times in order to reach the survey depth. Our simulations suggest that a survey like LADUMA (Looking at the Distant Universe with MeerKAT Array), which aims to achieve its survey depth of 16 µJy/beam in a 72 kHz at 1.42 GHz by observing the same field for 1000 hours, will be able to reach its target depth in the presence of these artefacts. We also present stimela, a system agnostic scripting framework for simulating, processing and imaging radio interferometric data. This framework is then used to write an end-to-end simulation pipeline in order to quantify the resolution and sensitivity of the SKA1-MID telescope (the first phase of the SKA mid-frequency telescope) as a function of frequency, as well as the scale-dependent sensitivity of the telescope. Finally, a stimela-based reduction pipeline is used to process data of the field around the source 3C147, taken by the Karl G. Jansky Very Large Array (VLA). The reconstructed image from this reduction has a typical 1a noise level of 2.87 µJy/beam, and consequently a dynamic range of 8x106:1, given the 22.58 Jy/beam flux Density of the source 3C147.
- Full Text:
- Date Issued: 2018
Teacher-in-role as a problem-posing method for learners in a special needs school in South Africa
- Authors: Hellemann, Phemelo Cordelia
- Date: 2018
- Subjects: Special education -- Activity programs -- South Africa , Special education -- South Africa , Drama in education -- South Africa , Drama -- Therapeutic use -- South Africa , Children with mental disabilities -- Life skills guides , Kuyasa School (South Africa)
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/62549 , vital:28205
- Description: Paulo Freire’s problem-posing pedagogy urges for a creative and collaborative educational environment between learners and teachers that encourages critical thinking and engagement. This research explores how special needs pedagogical approaches in South Africa can transform their classroom practices to embrace creative and collaborative teaching methods such as drama. Drama-in-education (D-i-E) is an area where the learner and teacher relationship is characterised by creativity and engagement. This qualitative study considers the uses of drama as a teaching and learning method for learners in the Skills Phase class at Kuyasa Special School, Grahamstown. The research aimed to provide learners with intellectual barriers to learning with access to D-i-E. This was done through a series of practical drama lessons, which broadly aimed to enhance life skills and work environment competencies such as communication, problem-solving and interpersonal relations. The lessons followed a cross- curricular approach that integrated aspects of the Life Orientation (Grade 10-12) curriculum and the Drama (Creative Arts Grade 7-9) curriculum. This practice-led study reflects on how Dorothy Heathcote’s teacher-in-role (t-i-r) drama technique was implemented to teach topics and themes extracted and adapted from the Life Orientation learning area. This drama-based pedagogy employs three elements of Freire’s problem-posing education model, which are learner-centred, problem-posing and liberated pedagogy. The study discusses how these elements manifested in the lessons conducted, and how this approach benefited and improved the learners’ critical thinking skills, self-esteem and confidence. This study therefore provides a broad understanding of the possibilities of a drama-based pedagogy within a South Africa context of learning disability, proposing an alternative pedagogical approach in South African special schools. The findings contribute to the academic literature on D-i-E in South Africa and advocate for the inclusion of learners with learning disabilities within the performing arts education.
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- Date Issued: 2018
Characterisation, antimalarial and biological activities of secondary metabolites from leaves of anonidium mannii
- Authors: Makoni, Pfungwa Gervase
- Date: 2017
- Subjects: Anonidium mannii -- Therapeutic use , Botanical chemistry , Annonaceae -- Therapeutic use , Apocynaceae -- Therapeutic use , Malaria -- Chemotherapy , Tuberculosis -- Chemotherapy , Bacterial diseases -- Chemotherapy , Cancer -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/4797 , vital:20725
- Description: Anonidium mannii is a plant of the Annonaceae genus which is used traditionally in Africa for the treatment of gonorrhoea, malaria, cancer, skin inflammation and dysentery. In this study we will evaluate antimalarial, antifungal, anti - tuberculosis, antibacterial activities and cytotoxicity of different fractions in order to provide a scientific rationale for the traditional use of Anonidium mannii as well as provide possible novel drugs in the treatment of multi drug resistant strains of parasites and bacteria. Extracts from dried leaves were obtained by using solvent extraction and different fractions obtained using column chromatography eluted with solvents of varying polarities to obtain a wide range of metabolites. The antimalarial activity of the various fractions and some pure compounds was evaluated using plasmodium lactate dehydrogenase (pLDH) assay. Cytotoxicity was evaluated using HeLa cells while anti – tuberculosis assay was evaluated using the green fluorescent protein. Antibacterial activity of the extracts was evaluated using micro-dilution assay against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) bacteria and Gram-negative (Escherichia coli and Salmonella typhi) bacteria. Antifungal activity was evaluated against Candida albicans. The antimalarial assays yielded some fractions with promising IC50 values. The selected fractions yielded activities ranging between 0.73 μg/mL and 20.23 μg/mL. The fraction with the best activity was obtained from a hexane/ethyl acetate fraction. AM1C, a cholestane, showed the best activity from the pure metabolites that were screened. AM3C, stigmasterol, a pure compound gave the best antifungal activity with an MIC of 0.063 μg/mL. AM9C another pure compound (sterol) showed the best activity against S. typhi with a value of 0.031 μg/mL. AM2C a pure compound showed an activity of 0.063 μg/mL against E. faecalis. The best cytotoxicity was demonstrated by the fraction C2AM3P with a cell viability of 7.1 ± 0.2 % while AM1C had a viability of 20.2 ± 1.2 %. Several pure metabolites were isolated and four of these were positively identified as steroids. Of these steroids the structure of three novel metabolites from A. mannii was deduced. The study showed promising antibacterial, antifungal, anti – tuberculosis, antimalarial and anticancer activity of A. mannii. These results validate the use of A. manni against cancer, skin inflammation which is caused by fungus, malaria and bacterial diseases.
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- Date Issued: 2017
Implementing uncertainty analysis in water resources assessment and planning
- Authors: Hughes, Denis A , Mohobane, T , Mallory, S
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438281 , vital:73448 , ISBN 978-1-4312-0629-2 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2056-1-14.pdf
- Description: The main objective of the project was to contribute to the incorporation of uncer-tainty assessments in practical water resource decision-making in South Africa. There are three main components to this objective. The first is the quantification of realistic levels of uncertainty that are as low as possible given the available infor-mation (reducing uncertainty). The second is the availability of tools to implement uncertainty analysis across the broad spectrum of data analysis and modelling plat-forms that form part of practical water resources assessment (including hydrologi-cal and water resources yield models). The third relates to the issue of using uncer-tain information in the process of making decisions about the design, development or operation of water resources systems. The latter includes social, political and economic uncertainties as well as the hydrological uncertainties that are directly addressed in this report. None of these are independent and all are associated with the fundamental issue that all of the role players should understand the key con-cepts of uncertainty and that virtually all of the information we use to make deci-sions is uncertain. One of the major challenges in this project as well as the previous WRC-supported project on uncertainty methods, was the lack of understanding of some of the key issues, or a lack of appreciation of the importance of uncertainty in all water resources decision-making.
- Full Text:
- Date Issued: 2015
The use of Daphnia spp. and indigenous river invertebrates in whole effluent toxicity testing in the Vaal Catchment.
- Authors: Muller, Nikite W J , Palmer, Carolyn G
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438048 , vital:73431 , ISBN 1 86845 855 5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/815-1-02.pdf
- Description: Freshwater is vital to societal, and environmental, well-being and any changes in the distribution, abundance and quality of water resources and ecosystems are detrimental to this societal and environmental sus-tainability. Increasing socio-economic activities world-wide have been accompanied by increased pollution stress on the aquatic environment. The need for improved efficiency in water quality management is urgent and immediate and it is important that policy to manage freshwater sys-tems is underpinned by sound science. Strategies to manage receiving water quality have been implemented world-wide and include chemical monitoring, biological monitoring and toxicological assessments, all of which are supported by on-going research. Water quality management in South Africa has come a long way since 1919, when it was first promulgated (Union Health Act 36 of 1919; van der Merwe and Grobler, 1990) but only included sewage effluent. Later amendments broadened water quality management to include effluent discharge from industry, mining and storm-water runoff. However, despite these and uniform, and general, effluent standards (UES), as well as DWAFs recognition of the need for integrated water resource management, water quality in the resources continue to deteriorate (DWAF, 1995; Basson etal 1997).
- Full Text:
- Date Issued: 2002
Workplace Reorganisation Course
- Authors: DITSELA
- Date: 2002
- Subjects: Development Institute for Training,Support and Education for Labour (DITSELA)
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/175688 , vital:42606
- Description: This booklet is about the way in which work is being restructured in the workplaces of South Africa. It is the first in a series of booklets dealing with various restructuring issues faced by workers. There are major changes being made in the workplace that impact on the lives of workers. For workers, restructuring brings changes to the way that their workplace is organised and this will impact on their working lives. These changes could hold threats or opportunities for workers. This first book will explain what is meant by restructuring and look at why many companies in South Africa are considering restructuring. It will also look at some trade union strategies around restructuring and some suggestions for negotiating restructuring.
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- Date Issued: 2002
Exploring new terrain - tackling a tri-media approach to the 1999 election: an analysis of online coverage of elections by media organisations in their respective countries and recommendations for multi-platform publishing within the South African Broadcasting Corporation to cover the national election
- Authors: Naidoo, Kameshnee
- Date: 1999
- Subjects: South African Broadcasting Corporation , Elections , Journalism -- Political aspects -- South Africa , Mass media -- Political aspects -- South Africa , Internet , Electronic news gathering , Television broadcasting of news -- Political aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3473 , http://hdl.handle.net/10962/d1002928 , South African Broadcasting Corporation , Elections , Journalism -- Political aspects -- South Africa , Mass media -- Political aspects -- South Africa , Internet , Electronic news gathering , Television broadcasting of news -- Political aspects
- Description: This study attempts to analyse the way foreign media organisations have used the Internet to inform, educate and mobilise citizens for participation in their national election. These foreign experiences provide a framework with which to analyse the implications for the SABC as a public broadcaster of the next elections in South Africa. The research was informed by theories of media and democracy. One of the most powerful features of the new technology is its technical ability to facilitate an interactive flow of information. This research examines the concept of cyberdemocracy and the implications for the SABC, especially as it is planning on launching an online election strategy. The democratic roles of journalism and the implications for the SABC are also discussed. As a public service broadcaster, the SABC is bound to educate, inform, and mobilise voters for participation, build community and national identity and scrutinise the poll in the interests of transparency, accountability and fair play. International journalists are advocating a new type of journalism, called public or civic journalism, which combines these roles. This research draws primarily on qualitative research methods, using a case study methodology. It draws upon direct observation and interview methodology in the fieldwork. However, it also uses some quantitative methods in the analysis of the websites and the SABC research.Finally, the research analyses the situation at the SABC and provides recommendations for the election website within this context.
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- Date Issued: 1999
Organisational culture in a South African non-governmental organisation: the challenge of a changing environment
- Authors: Dollar, Disa G
- Date: 1999
- Subjects: Psychology, Industrial -- South Africa , Non-governmental organizations -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3248 , http://hdl.handle.net/10962/d1015510
- Description: Using Schein's (1992) notion of organisational culture, this study explored the position of a South African nongovernmental organisation (NGO) in the changing environment of post-apartheid South Africa. The study pursued three central goals: to describe the organisational culture of a South African NGO; to examine the tensions that have emerged owing to the changing nature of the organisational culture; and to analyze the organisational culture in relation to the changing NGO environment. The basic assumptions of the organisation regarding networking, the relationship with the government, funders and funding, leadership, human resource development, and service delivery, were collected. A single case study design was employed, with a sample of eight participants (representing the four different sections of the NGO) being drawn. Data were collected through documentary analysis, a focus group, and eight individual interviews using the critical incident technique. Analysis was performed using various qualitative data analysis techniques. The researcher found that participants considered networking, a cooperative relationship with the government, a proactive approach to obtaining funding, effective leadership and human resource development, and a good reputation for service delivery, to be essential for NGO survival. NGO basic assumptions are undergoing a transformation process, and tensions exist between long-standing and emerging assumptions. It was found that the transformation of assumptions is enabling the NGO to adapt to the challenges of the changing environment.
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- Date Issued: 1999
The political significance of the liberal media coverage of District Six from 1949 to 1970
- Authors: Marquard, Andrew Keith
- Date: 1996
- Subjects: Mass media -- Political aspects , District Six (Cape Town, South Africa) , District Six (Cape Town, South Africa), In The Press
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2802 , http://hdl.handle.net/10962/d1003012 , Mass media -- Political aspects , District Six (Cape Town, South Africa) , District Six (Cape Town, South Africa), In The Press
- Description: The political significance of the media coverage of District Six is approached in the following way: the issue is approached theoretically by posing the question of the general political significance of news as a communicative form. This question is resolved by an examination of the complicated relationship between the tradition of political thought and the development of modem political forms, specifically the issue of the importance of communication in modern political forms. This is explored by considering the problem of the political outlined by Heller. Arendt reconceptua1izes the problem in terms of political judgement, which is discussed in relation to postmodernism and Wittgenstein's philosophy of language, to establish a new conceptualization of political judgement based on Arendt's view of narrative and Benjamin's writing on history. This conceptualization is used to formulated a notion of the general political significance of news, which is a form of political judgement related to a specific political culture. On this basis the media material is analysed in terms of two processes: the representation of District Six in the liberal media, and the representation of the political process surrounding its racial zoning and demolition. It is concluded that the media coverage of Distract Six during this period is characterized by a political culture termed the politics of the ordinary based on a reification of 'Europe' as part of a ' colonial attitude', and the idealization of specific urban forms, with a special relationship to urban planning. Thus the political significance of the media coverage resides in the perpetuation of this political culture, representative of the politics of the white English-speaking middle class, in terms of which an authentic urban politics is not conceivable. Additional conclusions are also drawn concerning the relationship between this political culture and the politics of Apartheid.
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- Date Issued: 1996
Preparing for national elections: workbook: a civic education programme
- Authors: University of the Western Cape, Centre for Development Studies
- Date: 1992-03
- Subjects: Elections -- Planning -- Handbooks, manuals, etc. , Election monitoring -- Handbooks, manuals, etc.
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/72868 , vital:30125
- Description: Today Namibia is at the crossroads of its independence. The agony of death and destruction that the Namibians have endured for the past 105 years of colonial oppression is about to come to an end and freedom is in sight. The process of transition to independence has already started. On 1 November 1989, the Namibian people will exercise their long-denied right to self-determination by electing their own leaders who. by virtue of being elected by the masses will have the sovereign right to draft the constitution of independent Namibia. This will bring about a new political and socio-economic order. The task before the Namibian people is to seize this historic opportunity and ensure that they join hands to safeguard the revolutionary gains we have made in bringing our country to the threshold of independence. Seizing this opportunity means, first, to register as a voter, and second, to vote and send to the Constituent Assembly men. and women with a revolutionary will, honourable record, vision for a better future, integrity, experience and proven ability to fight for the interests of the broad masses of the Namibian people. Such men and women are to be found in SWAPO. SWAPO has stood tall in the face of formidable odds over the last twenty-nine years of its struggle to free Namibia. Because of this fact. SWAPO had participated in the formulation of Resolution 435 and fought bravely for the last 11 years for its implementation. The motivating force behind this struggle has always been to guarantee that power is given to the Namibian people to decide the future of our country' through free and fair elections. Now that Resolution 435 is being implemented, the Central Committee of SWAPO has the honour to place before the people of Namibia its concrete programme of action in the form of SWAPO’s policy positions on a broad spectrum of political, economic, social and cultural issues. Together, these policy'positions form SWAPO's Election Manifesto. , sponsored by the Centre for Development Studies, University of the Western Cape & the National Democratic Institute for International Affairs, November 6-16, 1991
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- Date Issued: 1992-03