Bacterial degradation of waste coal
- Authors: Madikiza, Lwazikazi
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54576 , vital:26590
- Description: As an energy source coal has one of the largest agglomerations in the world. Consequently mining of coal creates large volumes of waste in the form of low ranks coals. The complex structure of coal makes it difficult for the microorganisms to degrade and relatively few bacteria and fungi have been shown to break down coal. This study aimed to investigate bacteria not previously known to degrade coal. In this study bacteria were isolated from hydrocarbon contaminated sites and inoculated in coal medium where coal served as the only carbon source. Three strains produced a yellow – brown supernatant after 14 d of incubation at 30 °C. Bacteria generating a yellow – brown coloured supernatant were presumed to possess coal degrading capabilities and the best performing of these bacterial species was identified using 16s rDNA as Bacillus flexus. Scanning electron microscopy showed that there was a close association between the bacterium and substrate coal. The close association of bacteria to substrate suggested that these organisms were able to maximize solubilisation. FT-IR spectroscopic analysis demonstrated the addition of single bonded compounds COOH, OH, CN and CH that were absent prior to bacterial interaction. The increase in oxygen rich regions indicated degradation of the coal substrate. Elemental analysis showed that there was a decrease in carbon content from 47 % to 24 % during the 14 day incubation period. Reduction in coal carbon content was assumed to be due to bacterial utilization for metabolism and growth particularly as untreated coal substrate showed minimal loss of carbon. Analysis of the residual culture medium revealed that there was a linear increase in humic-like substance concentration for 8 d, coincident with increased coal biosolubilisation and colour change. Laccase activity was insignificant, and at 13 d enzyme activity was only 5×10-3 U/L suggesting that B. flexus may use a different mechanism to degrade coal. Residual culture medium remaining after bacterial action on the coal substrate appeared to possess plant growth promoting activity. This soluble biodegradation product with characteristics similar to humic acid-like substances was shown to impact growth of radish cotyledons. Expansion of isolated radish cotyledons was enhanced by 140% when incubated in coal biodegradation product. In conclusion, this study has yielded B. flexus and two other unidentified bacteria, isolated from polyaromatic hydrocarbon contaminated soils, and demonstrated the ability of these microorganisms to degrade waste coal. Further studies to elucidate the mechanism of coal breakdown by B. flexus, synergies with other coal degrading microorganisms, and incorporation of bacterium into Fungcoal bioprocess technology is imminent.
- Full Text:
- Date Issued: 2014
Characterization and application of phthalocyanine-magnetic nanoparticle conjugates anchored to electrospun polyamide nanofibers
- Authors: Ledwaba, Mpho
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54610 , vital:26593
- Description: This work presents the syntheses, photophysical and photochemical characterization of zinc tetracarboxyphenoxy phthalocyanine (ZnTCPPc, 3) and its gadolinium oxide nanoparticle conjugate (4). By means of spectroscopic and microscopic characterization, the conjugation of the ZnTCPPc to the silica coated gadolinium oxide nanoparticles (Si-Gd2O3 NPs, 2) through an amide bond was confirmed. The thermal stability, morphology, nanoparticle sizes and their conjugates with the Pc were studied using ThermoGravimetric Analysis (TGA), Fourier Transform Infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and powder X-ray diffractometry (XRD). Conjugation of ZnTCPPc to the magnetic nanoparticles, proved to have a negligible effect on the photophysical parameters of the phthalocyanine, where a slight decrease in fluorescence and triplet quantum yields and lifetimes was observed. The singlet oxygen quantum yield, however, increased slightly upon conjugation, suggesting that the overall efficiency of the ZnTCPPc as a photosensitizer had improved. Physical mixing of the ZnTCPPc and the silica-coated gadolinium nanoparticles also showed an improvement in the singlet oxygen quantum yield and triplet lifetime, also showing an enhanced efficiency for the photosensitizer and therefore photocatalysis. ZnTCPPc (3) alone and the Pc-gadolinium oxide nanoparticle conjugate (4) were therefore electrospun into nanofibers to create a solid support. The fibers were characterized and their diameter sizes and composition was studied confirming the incorporation of the phthalocyanine and gadolinium oxide nanoparticle. Increased singlet oxygen generation resulted in increased Photodegradation of the environmental pollutant Orange G and the fibers were found to be more efficient as photocatalysts compared to the photosensitizer in solution. The nanomaterial may therefore be applied to the photodegradation of Orange G.
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- Date Issued: 2014
Dangerous people and places : a community newspaper's constructions of crime
- Authors: Raymond, Leigh Alice
- Date: 2014
- Subjects: Grocott's Mail (Grahamstown, South Africa) , Community newspapers -- South Africa -- Grahamstown , Crime and the press -- South Africa -- Grahamstown , Newspapers -- Objectivity , Mass media policy -- South Africa -- Grahamstown , Social responsibility of business -- South Africa -- Grahamstown , Police and the press -- South Africa -- Grahamstown
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3527 , http://hdl.handle.net/10962/d1013091
- Description: This thesis argues that there is a clear imbalance in the representation of crime in the newspaper, Grocott’s Mail, in Grahamstown, in the Eastern Cape of South Africa. The thesis concludes that the system of marginalisation and segregation which was established during the apartheid era is the foundation for the continued segregation and marginalisation of certain groups of people in Grahamstown as depicted in crime journalism. Previous research shows that not only people, but spaces are marginalised through media representations of crime. As people are represented as dangerous, so too the spaces they occupy become dangerous spaces. Importantly, the research shows that discourses of marginalisation are present in newspaper reports reproducing the discourses prominent in society, and in turn, the newspaper itself perpetuates these marginalising discourses. This extends into the coverage that different crimes receive in newspapers. For instance, the reports show that a middle-class audience will be more concerned with property crime in middle-class neighbourhoods, than other crimes in lower-class neighbourhoods. I argue that not only the type of crime, but the severity, the effect, and the necessity for justice represented by the newspaper, are all largely determined by the region of the crime. Further, I show that the criminal is not only demonised and represented as individually deviant in the reports in the newspaper, but that these representations are made by this newspaper because they are deeply imbedded as a discourse in society. This is partly because this newspaper has taken on a monitorial role, requiring neutral reporting from journalists, and a dedication to surveying the processes of state institutions, like the police and courts. As a result, the ways in which crime is reported on in the newspaper is fairly well fixed, making it difficult for journalists to conceive of different ways of reporting crime. The representations of the criminal justice system that the monitorial media, this newspaper included present, are a careful balance between the interest of the public, and the need to preserve relationships with sources. The monitorial media in general, and this newspaper in particular, represent the criminal justice system. The relationship between the police and the newspaper, and the courts and the media, therefore strongly influences the way in which crime news is reported. In particular, crime news is represented from the perspective of the criminal justice system. This research was carried out using Critical Discourse Analysis, qualitative interviews, and focus group interviews.
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- Date Issued: 2014
Development and assessment of sustained release stavudine loaded microparticles
- Authors: Zindove, Chiedza Cathrine
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54722 , vital:26603
- Description:
Stavudine (D4T) has been used as first line treatment for HIV/AIDS and is part of highly active anti retroviral treatment (HAART). It is an affordable medicine and its use is beneficial in resource limited settings. However D4T exhibits dose dependent side effects that may lead to non-adherence in patients. This study was undertaken to formulate, develop and manufacture a dosage form that could reduce dose dependent side effects by decreasing the dose of D4T but still exhibit antiretroviral (ARV) activity. The use of sustained release (SR) formulations of D4T that ensure constant levels of the D4T in the body would not only optimize therapy but also reduce the incidence of side effects thereby increasing patient adherence. SR microparticles containing 30mg D4T were manufactured and loaded into size 3 hard gelatine capsules prior to analysis. The D4T microparticles were manufactured by microencapsulation using non-aqueous oil-in-oil solvent evaporation approach. D4T-excipient, excipient-excipient interactions and D4T purity were assessed using Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Copolymers synthesized from acrylic and methacrylic acid esters viz., Eudragit® RSPO and S100 were used as rate retardant materials and the effect of microcrystalline cellulose (Avicel® PH102) on the microparticles was also investigated. Magnesium stearate was used as a droplet stabilizer and n-hexane was added to harden the microspheres formed in a liquid paraffin continuous phase. The microparticles were optimized using a Box Behnken design and Response Surface Methodology (RSM). The microparticles were characterized in terms of their flow properties and encapsulation efficiency (% EE), in addition to visualization of the surface morphology with Scanning Electron Microscopy. In vitro D4T release studies were performed using USP Apparatus III in media of different pH and the samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection that had been developed and optimized using a Central Composite Design (CCD). The method was validated according to ICH guidelines. The IR spectra and DSC thermographs revealed that D4T exhibited thermal stability and there was no evidence of D4T-excipient and excipient-excipient interactions. The microparticles that were produced were white, free flowing and were obtained in a high yield with high encapsulation efficiency. Scanning Electron Microscopy studies revealed that the microparticles were spherical and porous in nature. In vitro D4T release extended to 12 hours and the mechanism of release was established using model dependent methods by fitting the data to a Zero order, First order, Higuchi and Hixson Crowell model. It was observed that the mechanism of D4T release was diffusion-controlled and that the data was best fitted to the Higuchi model with correlation coefficients > 0.9. The release mechanism was confirmed using the Korsmeyer-Peppas model that revealed that most of the formulations exhibited anomalous transport kinetics with the release exponent, n, ranging from 0.5
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- Date Issued: 2014
Gold mineralization in a high grade metamorphic terrane in the Handeni District, Eastern Tanzania
- Authors: Bitesigirwe, Godfrey Stephen
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54756 , vital:26609
- Description: Most orogenic type gold deposits are formed under low greenschist facies to mid amphibolite facies metamorphic conditions and deposition is either structurally or lithologically controlled. A few known gold deposits found in high grade metamorphic terranes include those in the Yilgarn craton in Australia, Renco in Zimbabwe, Hemlo in Canada and the recently discovered Handeni deposit in Tanzania. Within Tanzania, gold deposits are mainly hosted in Archaean low grade metamorphic rocks commonly known as the Lake Victoria greenstone belt. The greenstone belts of Tanzania are of Nyanzian age (> 2.5Ga) and are located to the south and east of Lake Victoria on the Tanzania craton. The Tanzania Craton is surrounded by Usagaran 1.9 Ga rocks (the east African orogenic belt (EAO) better known as the Mozambique belt) to the east and the Ubendian belt to the south and west. Published reports show that the eastern part of the Tanzania Craton is dominated by the fragments of Archaean rocks. Metamorphism along East Africa and the Tanzania Craton is due to several geological events. These geological events include the intrusion of granites in the Archaean Tanzania Craton (3 Ga), subduction of ocean plate resulted to the formation of Usagaran belt (1.9 Ga), opening and closure of Mozambique Ocean, which resulted in the formation of the Mozambique belt between 700 – 800 Ma and the Pan African orogeny at 640 – 620 Ma, which is associated with the formation of Gondwana. It is believed that fragments from the Archaean Tanzania craton were re - metamorphosed during these events. The Handeni project (the focus of this thesis) is located in the northern portion of the eastern part of the Usagaran belt (1.9 Ga) comprising the eastern part of Archaean Tanzania Craton. The area is characterized by Proterozic rocks of basaltic composition. The documented 2.7 Ga rocks at the Kilindi Handeni Superterrane at the northern part of the Usagaran belt correlate well with 2.7 Ga of Nyanzian rocks of Archaean Tanzania craton. The Handeni project area is geologically dominated by metamorphosed and deformed units of quartzofeldspathic gneisses, migmatitic gneiss, garnet silicified rock, garnetiferous amphibolite, garnetiferous granulite, graphitic schist and hornblende pyroxenite. Intensive deformation features that were developed include folds (sheath folds, micro and macro scales), faults, shears and regional thrusts. This thesis focuses on identifying the protolith of the rocks, alteration minerals, and metamorphic assemblages in the project area in order to understand the timing of gold mineralization. Geological investigation of core, ore petrology and mineralogy, mineral composition by using JEOL microprobe analysis and XRF analysis of bulk rocks were utilized. All the analytical work was done at the Geology laboratory, Rhodes University. Petrographic analysis shows that the rocks sampled in the study area are characterized by alteration minerals such as calcite, dolomite and sericite. Sulphide minerals including chalcopyrite, pyrrhotite, pyrite, pentlandite and gersdorffite were identified. Gold mineralization is associated with disseminated sulphides in association with trace amounts of base metals. Four rock types were proposed as host rocks for the mineralization, namely garnet silicified rock with superimposed quartz veins, garnetiferous amphibolite, garnetiferous granulite and hornblende pyroxenite. Fold troughs, filled fractures associated with episodes of folding, quartz veins and shear zones are suggested as gold precipitation sites. The presence of high grade metamorphic rocks containing gold, intermediate to low grade assemblages with sulphides and associated hydrothermal alteration as well as a complex deformation history suggests that the Handeni mineralization took place over an extended time period stretching from a ductile to a brittle environment.
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- Date Issued: 2014
Inside the river
- Authors: Buzani, Mangaliso Welcome
- Date: 2014
- Subjects: South African poetry (English) , Xhosa poetry
- Language: English , Xhosa
- Type: text , Thesis , Masters , MA
- Identifier: vital:5971
- Description: My collection is of imagistic associative poetry, influenced by Spanish and other kinds of modernism, and written in my two languages, isiXhosa and English. My approach to producing these poems is first via the mastery of sound, not on the actual meaning of a poem; working on the meaning would be the last stage. The language of each poem will be encountered as it comes down on the paper, leading me to the words meaningful for that particular poem.
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- Date Issued: 2014
Invariant optimal control on the three-dimensional semi-Euclidean group: control affine and quadratic Hamilton-Poisson systems
- Authors: Barrett, Dennis Ian
- Date: 2014
- Subjects: Automorphisms , Symmetry (Mathematics) , Lyapunov stability , Geometry, Riemannian , Geometry, Affine , Elliptic functions
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64805 , vital:28605
- Description: In this thesis we consider invariant control systems and Hamilton-Poisson systems on the three dimensional semi-Euclidean group SE(1,1). We first classify the left-invariant control affine systems (under detached feedback equivalence). We provide a complete list of normal forms, as well as classifying conditions. As a corollary to this classification, we derive controllability criteria for control affine systems on SE(1,1). Secondly, we consider quadratic Hamilton-Poisson systems on the (minus) Lie-Poisson space se(1,1)*. These systems are classified up to an affine isomorphism. Six normal forms are identified for the homogeneous case, whereas sixteen representatives (including several infinite families) are obtained for the inhomogeneous systems. Thereafter we consider the stability and integration of the normal forms obtained. For all homogeneous systems, and a subclass of inhomogeneous systems, we perform a complete stability analysis and derive explicit expressions for all integral curves. (The extremal controls of a large class of optimal control problems on SE(1,1) are linearly related to these integral curves.) Lastly, we discuss the Riemannian and sub-Riemannian problems. The (left-invariant) Riemannian and sub-Riemannian structures on SE(1,1) are classified, up to isometric group automorphisms and scaling. Explicit expressions for the geodesics of the normalised structures are found.
- Full Text:
- Date Issued: 2014
Lived bodies: women’s experience of sex and gender
- Authors: Lothian, Julie-Anne
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/69445 , vital:29538
- Description: This thesis will discuss the category of women, as a social group, through a phenomenological understanding of women’s subjective experiences. In arguing for the phenomenological perspective of the lived body, I show the ways in which other conceptions of women’s embodied subjectivity ultimately fail to provide comprehensive accounts of the lived experience of being a woman. I begin with an investigation into how biological determinists hypothesise women’s bodies as sexed. I then move to respond to Judith Butler’s poststructuralist feminist account of the gendered body. Finally, I argue that the embodied experience of being a woman is best explained as an ambiguous relationship between socially constructed expectations of femininity and biological materiality.
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- Date Issued: 2014
Modelling the spatial and genetic response of the endemic sparid: Polysteganus praeorbitalis (Pisces: Sparidae) to climate change in the Agulhas Current system
- Authors: Isemonger, Devin Neil
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54509 , vital:26576
- Description: The Scotsman Seabream, Polysteganus praeorbitalis, is one of several large, slow-growing members of the Sparidae family of fishes endemic to the Agulhas Current system in the Western Indian Ocean (WIO). Relatively little research has been conducted on this species despite its importance to both recreational and commercial line fisheries in South Africa and the drastic decline in catch per unit effort (CPUE) that has been recorded since the 1940s. Changing sea temperatures as a result of global climate change are further expected to affect the distribution and abundance of many fish species based on their thermal tolerances, life histories and population structures. The ability of these species to shift their distribution and adapt to new environments and thermal conditions will depend to some degree on the levels of genetic variation and gene flow, within and between populations. A combined approach using species distribution modelling and genetic analyses may prove to be a useful tool in investigating the potential effects of climate change on the distribution and genetic diversity of species. An ensemble species distribution model (SDM) based on 205 occurrence records and 30 years of Reynolds Optimum Interpolated (OI) sea surface temperature data was constructed to predict the distributional response of P. praeorbitalis to climate change in the Agulhas Current system. The ensemble SDM displayed a true skill statistic (TSS) of 0.975 and an area under the receiver operating curve (ROC) of 0.999, indicating good model fit. Autumn and winter minimum temperatures, as well as bathymetry, were the most important predictor variables in the majority of models, indicating that these variables may directly constrain the distribution of P. praeorbitalis. In particular, the southern range edge of this species appeared to be constrained by autumn and winter minima, with high model agreement on this range edge. Conversely, the northern range limit showed poor model agreement leading to a gradual reduction in occurrence. This indicates that this range edge may be constrained by other factors not included in the models such as species interactions. The ensemble SDM projected the current range of P. praeorbitalis to be 1500 km², smaller than the published range for this species. The model underestimated the northern range edge of this species by approximately 5° latitude when binary transformed. This is probably due to the rarity of this species in the landings of the Mozambican linefishery, which was assumed to be an indication of low abundance of P. praeorbitalis in these waters. The absence of a specimen to verify the published northern range edge of this species indicates that the northern range edge produced by this model is likely to be closer to the actual range limit of the species. A range contraction of 30% occurring at both the northern and southern edge of P. praeorbitalis’ range and range fragmentation occurring, towards its northern range edge by 2030, was predicted. These changes are modelled to be the results of cooling related to the intensification of the Port Alfred upwelling cell and of warming predicted north of the Natal Bight and in southern Mozambique. Genetic analyses of the nuclear DNA (nDNA) S7 intron 1 and mitochondrial DNA (mtDNA) control region genes were carried out using 118 tissue samples of P. praeorbitalis collected at four main localities: the Eastern Cape, Transkei, southern KwaZulu-Natal and northern KwaZulu-Natal. Analyses of genetic diversity levels revealed relatively low diversity in the mtDNA dataset (Hd = 0.488; π = 0.004) and moderate levels of diversity in the nDNA dataset (Ad = 0.922; π = 0.005). The low levels of diversity observed in the mtDNA dataset might be explained by a number of factors, including high variation in spawning success, the negative effects of over-harvesting, or a recent population bottleneck. The last explanation is supported by characteristic star-shaped haplotype networks and unimodal mismatch distributions displayed by both datasets. These results, in conjunction with a significant (p = 0.005) negative Tajimas D value (-2.029) in the mtDNA dataset and significant (p = 0.0005) negative Fu’s F statistic in both the nDNA (F = -26.5) and mtDNA (F = -11.9) datasets, provide strong evidence for a recent population expansion after a bottleneck event in this species. Spatially, mtDNA diversity was highest in the Eastern Cape and lowest in the middle localities, while nDNA diversity showed the opposite pattern. These results may be indicative of differences in the sex ratio between localities, possibly as a result of the protogynous hermaphroditism that has been postulated for this species. Although pairwise comparisons and exact tests of population differentiation revealed no significant geneticdifferentiation between populations in the mtDNA dataset, there was some evidence of low levels of differentiation in the nDNA dataset. This occurred for comparisons between the Eastern Cape and Transkei (Fst = 0.039; p <0.05), and the northern KwaZulu-Natal (Fst = 0.045; p < 0.05).. This might be the result of one or a combination of factors including the effects of the Port Alfred upwelling cell on dispersal and gene flow, or the possibility of more than one spawning ground for this species promoting sub-structuring. A SAMOVA analyses run on the nDNA dataset maximised variance by grouping the Eastern Cape and southern KwaZulu-Natal together and Transkei and northern KwaZulu-Natal together in two groups. This revealed no evidence of spatial structure (p = 0.36), with only 3.30% of variation explained by this grouping. The removal of individuals below the estimated length at 50% maturity in the nDNA dataset, in order to test for temporal structure, resulted in stronger evidence of differentiation between the Eastern Cape and all other localities: Transkei (Fst = 0.081; p< 0.05), southern KwaZulu-Natal (Fst = 0.031; p<0.05), and northern KwaZulu-Natal (Fst = 0.078; p< 0.05). This indicates that some temporal genetic structure may exist between age classes within this species. The differentiation observed between the Eastern Cape and other localities, coupled with the high percentage of private haplotypes in the mtDNA dataset in this locality, indicates that this area is where P. praeorbitalis is most vulnerable to the potential negative effects of climate change on its genetic diversity. However, the vast majority of this species genetic diversity appears to reside towards the centre of its range where it is most abundant and the lack of strong genetic structure indicates high levels of gene flow. In conclusion, while P. praeorbitalis is vulnerable to range loss as a result of climate change, its genetic diversity is unlikely to be greatly affected.
- Full Text:
- Date Issued: 2014
Prioritising native fish populations for conservation using genetics in the Groot Marico catchment, North West Province, South Africa
- Authors: Van der Walt, Kerry-Ann
- Date: 2014
- Subjects: Native fishes Fishery management -- South Africa -- North West Fish populations Fishes -- Conservation -- South Africa -- Western Cape
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/69102 , vital:29390
- Description: The Groot Marico catchment in the North West Province is a National Freshwater Ecosystem Priority Area (NFEPA) because it represents unique landscape features with unique biodiversity that are considered to be of special ecological significance. Three native freshwater species Amphilius uranoscopus, Chiloglanis pretoriae and Barbus motebensis, have high local conservation importance and B. motebensis is endemic to the catchment and is IUCN-listed as vulnerable. The main objective of this study is to contribute towards the effective conservation of these three species in the Groot Marico River system by assessing their genetic structure to determine whether tributary populations of the three species comprise of one genetic population or whether they are divided into genetically distinct subpopulations, in order to prioritise areas for conservation. The central null hypothesis was that there is no genetic differentiation between tributary populations (i.e., panmixia) of B. motebensis, A. uranoscopus and C. pretoriae in the Groot Marico catchment, North West Province. In total, 80 individuals per species were collected, targeting at least 10 individuals per population from a total of eight populations (seven tributaries and the Groot Marico main stem) and across the study area. Samples were collected by electrofishing and specimens were euthanized using an overdose of clove oil. A sample of muscle tissue was removed for genetic evaluation and the remainder of the specimens served as voucher specimens. For the genetic evaluation, mitochondrial (ND2, cyt b) and nuclear (S7) genes were used. Genetic techniques used were DNA extraction, polymerase chain reaction (PCR), purification and sequencing. From the 240 individuals collected, 123 sequences for B. motebensis, 111 sequences for A. uranoscopus and 103 sequences for C. pretoriae were analysed across all three genes. Statistical analysis included looking at cleaned sequences in order to obtain models using MODELTEST (version 3.06). Population structuring and phylogeographic analysis was performed in Arlequin (version 2000), TCS (version 1.2.1) and PAUP*. Results indicated that for B. motebensis the null hypothesis could be rejected as there were two distinct lineages (the Draai and Eastern lineages) that demonstrated significant divergence in both the ND2 and S7 genes, suggesting historical isolation. The low divergence in the mitochondrial cytochrome b gene (0% < D < 0.8%) suggests that this isolation is not very old and is probably not comparable to species level differentiation. The null hypothesis was also rejected for A. uranoscopus as there were also significant levels of differentiation between tributary populations resulting in the identification of two lineages (the Ribbok and Western lineages). However, for C. pretoriae, the null hypothesis could not be rejected as there was no genetic differentiation between tributary populations i.e., one panmictic population. Therefore, due to each species showing different genetic structuring within the tributary populations, more than one priority area for conservation needs to be implemented. These priority areas of conservation where therefore evaluated based on the current conservation status of the species (B. motebensis being vulnerable on the IUCN Red List), the number of Evolutionary Significant Units for each species and the overall genetic diversity of all three species in the Groot Marico catchment. In total, four tributary populations were conservation priorities areas, these were the Draai, Vanstraatens, Ribbok and Kaaloog tributaries. The Draai, Vanstraatens and Kaaloog tributaries were selected as priority areas for B. motebensis (B. motebensis is considered to be the most vulnerable of all three species). The Draai tributary was selected due to the B. motebensis population within the tributary showing isolation from the rest of the tributary populations. In order to conserve B. motebensis from the Southern lineage, the Vanstraatens and Kaaloog tributaries were selected. Reasons for selecting these two specific tributaries within the Southern lineage were that the Vanstraatens tributary had unique alleles (three Evolutionary Significant Units) for B. motebensis and the Kaaloog tributary had high genetic diversity (HD = 0.889, ND2 gene) when compared to the other tributary populations. The Ribbok and Vanstraatens tributaries were selected as priority areas for the conservation of A. uranoscopus. The Ribbok tributary was selected as it showed isolation from the rest of the tributary populations, as seen with the Draai tributary (B. motebensis) and the Vanstraatens tributary was selected to represent the Western lineage as it had the highest diversity for both genes (ND2 and S7). The Ribbok tributary has the highest prioritisation when compared to the Vanstraatens tributary. Chiloglanis pretoriae occurs within the Draai, Vanstraatens, Ribbok and Kaaloog tributaries, therefore by prioritising these tributaries for conservation, C. pretoriae will in turn be conserved.
- Full Text:
- Date Issued: 2014
Synthesis and characterization of NaYGdF4 upconversion nanoparticles and an investigation of their effects on the spectroscopic properties of two phthalocyanine dyes
- Authors: Taylor, Jessica Mary
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54621 , vital:26594
- Description: Sphere and star shaped NaYGdF4:Yb/Er(Tm) upconversion nanoparticles were successfully synthesized utilizing a methanol assisted thermal decomposition approach and their chemical, spectroscopic and fluorescence properties were fully characterized. In addition, their influence on the spectroscopic and fluorescence properties of two phthalocyanines (Pcs) (unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) and aluminium octacarboxy phthalocyanine (Cl)AlOCPc) was investigated. Upconversion nanoparticles were found to produce characteristic upconversion fluorescence emissions in the blue, green, red and NIR regions and were also shown to possess paramagnetic properties. Simple mixing with an H2Pc in toluene was found to exert no change on the spectroscopic or fluorescence properties of the Pc while covalent conjugation to a (Cl)AlOCPc resulted in a large Q band blue shift accompanied by a decrease in fluorescence lifetimes in DMSO. The red light excitation mediated singlet oxygen generation of the H2Pc mixed with upconversion nanoparticles was investigated and singlet oxygen fluorescence lifetimes were found to decrease in the presence of the nanoparticles. Upconversion mediated singlet oxygen generation, by way of resonance energy transfer to the Pc, was also attempted using 972 nm excitation; however, no singlet oxygen was detected utilizing singlet oxygen NIR emission detection. Pending further work using alternative singlet oxygen detection methods, this suggests that while upconversion nanoparticles possess excellent fluorescent imaging capabilities, they are relatively inefficient in inducing singlet oxygen production simply when mixed with phthalocyanines. Despite this, by combining phthalocyanines and upconversion nanoparticles, we present a system capable of: multimodal imaging, using both upconversion and phthalocyanines emissions, singlet oxygen generation, via direct excitation of the phthalocyanine with red laser light, and, possibly, magnetic resonance imaging, as a result of doping the upconversion nanoparticles with Gd3+ ions.
- Full Text:
- Date Issued: 2014
The involvement of TRAP1 in the mitochondrial localization of STAT3 in mammalian cells
- Authors: Kadye, Rose
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/55760 , vital:26731
- Description: STAT3 (signal transducer and activator of transcription 3), an oncogene and transcription factor of genes involved in cellular differentiation, proliferation and immune function, that classically localizes in the cytosol and nucleus has also been found in the mitochondria. However, STAT3 does not have a mitochondrial transit peptide, and its mechanism for mitochondrial localization is unknown. Cytosolic Hsp90s chaperone STAT3 to the nucleus therefore we investigated the involvement of the nuclear-encoded mitochondrial Hsp90 molecular chaperone tumor necrosis receptor associated protein 1 (TRAP1) in STAT3’s mitochondrial localization. Using TRAP1 transient over-expression, STAT3 inhibitor S3I- 201 and Hsp90 inhibitor geldanamycin, we demonstrate that TRAP1 and STAT3 co-localize and co-immunoprecipitates in mammalian systems. Taken together with the observation that STAT3 potentially directly interacts with TRAP1, these data suggest that TRAP1 plays a role in the mitochondrial localization of STAT3.
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- Date Issued: 2014
“Pragmatic yet principled”: an assessment of Botswana’s Foreign Policy record as a small state
- Authors: Mahupela, Kabelo Moganegi
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/65290 , vital:28722
- Description: Expected release date-July 2019
- Full Text:
- Date Issued: 2014
What makes news on the front page? : an investigation of conceptions of newsworthiness in the East African Standard
- Authors: Nzioka, Roseleen M
- Date: 2013-06-19
- Subjects: East African Standard (Nairobi, Kenya) Journalism -- Social aspects -- Kenya Journalism -- Editing -- Kenya Newspapers -- Sections, columns, etc -- Kenya Mass media -- Political aspects -- Kenya Newspapers -- Kenya
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3519 , http://hdl.handle.net/10962/d1008178
- Description: Determining what is newsworthy is a daily challenge even to the very people who source news, produce and disseminate it. This study is part an exposition and exploration of the different approaches that media researchers have used to explain and determine the value of news. Like similar research before it, this study more specifically delves into the news selection process of news of one particular newspaper with the goal of investigating why and how news is selected for publication in the front page. News is the 'result of many forces: ranging from source power, journalistic orientation, medium-preference and market model, news values and production routines and processes. The study briefly expounds on the different definitions of news as perceived in terms of the developed and developing world. Just as journalists do not operate in a vacuum, a close examination of the various definitions reveals that news cannot be defined in isolation. Its definition is intrinsically tied to that of news values. Also explored here are debates about news values and their Western rootedness. Here reference is made to literature regarding theories on the social construction of meanings and on the gatekeeping concept.The study is informed by similar research in gatekeeping studies and sociology of news studies. It is important to state at the outset that the study is not concerned with how news is produced but why there is a bias for certain kinds of news. I am interested in explaining why and how the writers and editors at the East African Standard make decisions about what is worthy of being published on the front page of the newspaper. This distinction is necessary because the theories that inform this study transcend news sourcing and production. This study takes cognizance ofthe fact that one cannot separate social processes from the individual and vice versa. For this reason, this study investigates and analyses the biases of individual gatekeepers at the East African Standard as well as their collective biases. In the concluding section, this study calls for an alternative paradigm for journalism and news. The foregoing discussions in the other sections prove that a universal definition of news and what is newsworthy will not suffice and there is need to contexualise it.
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An analysis of the distribution and use of teaching aids in mathematics in selected Windhoek secondary schools
- Authors: Dzambara, Tobias Munyaradzi
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Namibia Teaching -- Aids and devices -- Research
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1344 , http://hdl.handle.net/10962/d1001410
- Description: This study investigates the types of mathematics teaching aids available at both public and private secondary schools in Windhoek. The study characterises their usage and source as well as teachers’ perceptions towards the use of such teaching resources in the Mathematics classroom. The study is grounded in an interpretive paradigm and employed a mixed methods approach to generate both quantitative and qualitative data in two sequential phases. Phase 1 of the research process, which involved 75 Mathematics teachers, took the form of an audit of the availability and use of teaching aids at 25 secondary schools in Windhoek. A case study methodology was adopted in Phase 2 which focused on five purposively selected schools that displayed different characteristics in terms of the availability of teaching resources. The study found that the majority of teachers at secondary schools in Windhoek have a positive attitude towards the importance and role of teaching aids in Mathematics, seeing them as promoters of hands-on engagement, visual reasoning, active participation and motivation amongst learners. However, in some instances schools are underresourced with respect to certain types of teaching aids, specifically graph boards, geoboards, geometric models and computers. A need for appropriate in-school support on the use of teaching aids was also identified
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- Date Issued: 2013
An investigation of the discursive construction of the Tanganyika-Zanzibar Union as nation in the Union Day coverage in The Citizen and Daily News newspapers from 2005 to 2011
- Authors: Dotto, Paul Casmir Kuhenga
- Date: 2013
- Subjects: Newspapers -- Research -- Tanzania , Press and politics -- Tanzania , Tanzania -- Politics and government -- 1964- , Zanzibar -- Politics and government -- 1964- , Press , Daily News , The Citizen , Union Day , Nation building
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3412 , http://hdl.handle.net/10962/d1001843
- Description: This study is concerned with the constructions of the Tanzanian nation in the press. It has confined its focus, first, to the coverage from 2005 to 2011 on Union Day that marks the Union between Tanganyika and Zanzibar and the formation of the United Republic of Tanzania and, second, to two prominent Tanzanian newspapers, namely the state-owned Daily News, and the privately-owned The Citizen on Union Day. As the Union remains a contentious issue, the relevance of this research relates to the press’s considerable power to shape understandings and influence attitudes. The study works within a broad cultural and media studies framework and is informed by a constructionist approach to representation and to culture, and to nation in particular. It also draws of journalistic theories of agenda-setting and the normative roles of the press to probe the agendas set by the press on Union Day and to interrogate how the two newspapers construct and frame the Union of Tanganyika and Zanzibar as nation. The research responds to the question: ‘How has the Tanganyika-Zanzibar Union been represented in The Citizen and Daily News newspapers from 2005 to 2011?’ It employs quantitative and qualitative (thematic) content analysis to investigate the coverage in the editorials and feature articles of The Citizen and Daily News newspapers on Union Day (26 April) of 2005 to 2011. This study finds that the government-owned newspaper, Daily News, publishes more articles related to Union on Union Day than the privately-owned, The Citizen and collaborates more determinedly with the state in the process of constructing the nation. However, both newspapers adopt a collaborative role consistent with the development journalism tradition that endorses an informal partnership between media and the state in the process of development (Christians et al, 2009:201). Both publications tend to emphasise the hegemonic ideology pertaining to Union while giving limited attention to challenges to such constructions. While both newspapers do identify certain problems of the Union and thus exercise a monitorial role to varying extents, it is apparent that the press in Tanzania tends to be largely acritical, perhaps attributable to a long period under single party rule
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- Date Issued: 2013
Constructions of nationhood in secession debates related to Mthwakazi Liberation Front in Bulawayo's Chronicle and Newsday newspapers in 2011
- Authors: Ndlovu, Mphathisi
- Date: 2013
- Subjects: Newspapers , Bulawayo , Matabeleland , Zimbabwe , Chronicle , Newsday , Secession , Devolution , Nationhood , Ndebele , Ethnic identity , Mthwakazi Liberation Front , Mthwakazi Liberation Front -- Zimbabwe , Mass media and nationalism -- Research -- Zimbabwe , Bulawayo (Zimbabwe) -- Newspapers , Matabeleland (Zimbabwe) -- History -- Autonomy and independence movements , Matabeleland (Zimbabwe) -- Social conditions , Zimbabwe -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3415 , http://hdl.handle.net/10962/d1001846
- Description: This study investigates the constructions of nationhood in two Bulawayo newspapers, the Chronicle and Newsday. Against the backdrop of the emergence of a secessionist movement, Mthwakazi Liberation Front (MLF), this research examines the discourses of nationhood in the secessionist debates raging in these two newspapers. This study is premised on a view that nationhood constructions cannot be understood outside the broader context in which these newspapers are embedded. Accordingly, it traces the roots and resurgence of Matabeleland separatist politics, exploring the political-historical forces that have shaped a distinctive Ndebele identity that poses a threat to the one, indivisible Zimbabwean national identity. Further, the study situates Matabeleland separatist politics within the broader African secessionist discourse challenging the post-colonial nation-building project on the continent. Informed by Hall’s (1992, 1996) constructivist approach to identity, it considers national identities as fragmented, multiple and constantly evolving. Thus, this study is framed within Hall’s (1997) constructivist approach to representation, as it examines the constructions of nationhood in and through language. The study uses qualitative research methods, as it examines the meanings of nationhood in key media texts. Informed by Foucault’s discourse theory, this research employs critical discourse analysis (CDA) to analyse 12 articles from the two newspapers. The findings confirm that the representations of nationhood in the two newspapers are influenced by their position within the socio-political context. The state-owned Chronicle legitimates the unitary state discourse advocated by ZANU PF. On the other hand, Newsday’s representations are informed by the discourses of the opposition political parties and civil society that challenge the dominant nation-building project. Thus, within this paper, secession and devolution emerge as alternative imaginaries that contest the authoritarian discourse of nationhood
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- Date Issued: 2013
Counting planes
- Authors: Rawlins, Isabel Bethan
- Date: 2013
- Subjects: Prose poems , Flash fiction , Short stories , English , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5966 , http://hdl.handle.net/10962/d1001816
- Description: This collection of prose-poems and flash fiction, together with a few short stories, shows how romantic relationships colour our perspectives on the world. The collection has echoes throughout of speakers' voices, theme, imagery and tone. There is a narrative logic too, but working on a subtle level of echo and resonance
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- Date Issued: 2013
Creating a new declaration of rights : a critical reconstruction of earth jurisprudence's global legislative framework
- Authors: Lenferna, Georges Alexandre
- Date: 2013
- Subjects: Universal Declaration , Rights , Earth , Environment , Ethics , Environmental law, International -- Research , Environmental law, International -- Philosophy , Environmental ethics -- Research , Nature conservation -- Law and legislation -- Research , Jurisprudence -- Research , Law -- Philosophy
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2704 , http://hdl.handle.net/10962/d1001979
- Description: This thesis aims to critique the Universal Declaration of the Rights of Mother Earth and its underlying moral justification in order to provide a stronger and improved version of both. In Chapter 1 I explore what sort of moral justification is necessary to establish the Universal Declaration on firm grounds and explore its relation to environmental ethics and rights discourse. I argue that a non-anthropocentric perspective is necessary to justify the Universal Declaration’s rights. In Chapter 2 I explore the underlying justification of the Universal Declaration as discovered in the works of Cormac Cullinan and Father Thomas Berry. I argue that their ethical framework is indeterminate, has many ambiguities and uncertainties, and, among other problems, it does not provide a clear action-guiding framework. In Chapter 3 I develop an alternative justification for the Universal Declaration. I argue against many predominant moral theories, that in light of our best scientific and moral understanding we should expand the realm of moral concern to include all living beings, a moral theory I call Life’s Imperative. In Chapter 4 I illustrate that Life’s Imperative is a much stronger, more coherent justification for the Universal Declaration, one that coheres with both our best understanding of the natural world and our relation to it, and to an environmental ethic reflective of that relationship. Unfortunately many of the weaknesses in the current implicit justification of the Universal Declaration have also led to it enshrining rights that are themselves problematic. In order to address these issues, I revise its rights to accord with the stronger justification that I established in Chapter 3. The end result of doing so is a revised version of the Universal Declaration
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- Date Issued: 2013
Dog wars : a Victorian steampunk adventure
- Authors: Molino, Nicolene Chloe
- Date: 2013
- Subjects: Creative writing , Fiction , South Africa , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5965 , http://hdl.handle.net/10962/d1001815
- Description: We're in an alternate universe, circa Dickensian London. Leofric Lieven, a local crime lord, is about to find the past catching up on him. The Romany Carnival has come to town, and a gypsy woman, his former lover and partner in crime, demands from him a favour which will redress his betrayal of years before: he must secure a stolen object and return it to her. But things go horribly wrong when local delivery boy Cards Bennish is kidnapped by Leofric’s competitor before he can deliver the goods that will cover Leofric's debt to the gypsy. In this world, humans can shape shift into animals, entirely or only partially, dog fighting is the favourite pastime for high stakes betting, and power belongs to the highest bidder. The gypsy’s final bet, for the highest stakes yet, will seal the fates of a number of people, for better or worse
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- Date Issued: 2013