Part II Zef/poor white kitsch chique
- Authors: Krueger, Anton
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225745 , vital:49255 , xlink:href="https://doi.org/10.1080/17533171.2012.715484"
- Description: Ninja, who fronts the freak hip-hop band Die Antwoord, might not be quite what Desmond Tutu had in mind when he described South Africans as the “Rainbow People of God,”24 a happy harmonious amalgamation of different races. In his introduction to their seminal comic track “Enter the Ninja,” Ninja presents himself, rather, as a mongrel gutter dog, both embracing and parodying a syncretic fusion of the many different cultures and races of South Africa, celebrating as well as subverting the rainbow nation discourse. As he said in an interview with News24: “South African culture is quite a fucking fruit salad … a fucking fucked rainbow nation. South Africa's totally fucked … but in a cool way.”25 The cool side of being “fucked” in this way is “Zef.” Zef denotes a particular style of vulgar humor (in the usual sense of the word “vulgar,” but also with a nod to its origin in the Latin vulgaris for “mob” or “commoners”), which has been emerging more and more in South Africa during the past decade. It involves a way of presenting a persona in a purposefully degrading way, exaggerating one's appearance and mannerisms as low class, ill bred, and boorish. I would like to consider the recent popularity of “Zef” and examine its connection specifically to popular Afrikaans folk rock culture, a lineage of white poverty, and the feeling of disgrace experienced by many white Afrikaners after the end of apartheid.
- Full Text:
- Date Issued: 2012
A study of the coordination behaviour of the lanthanide series with oxygen-donor ligands
- Authors: Kuhn, Kirsti
- Date: 2012
- Subjects: Chemical elements , Chemical reactions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10394 , http://hdl.handle.net/10948/d1009533 , Chemical elements , Chemical reactions
- Description: The reactions between the lanthanide nitrate salts and the ligand triphenylphosphine oxide (TPPO) gave rise to nine-coordinated complexes of the nature Ln(TPPO)3(NO3)3, for Ln = La – Dy, Er, Tm, in which the Ln(III) centre is coordinated to three phosphoryl oxygen atoms and three bidentate nitrate ligands. Generally, the geometry can be described as being mer-octahedral, where the nitrate ligands are considered as monoatomic species. The product of the reaction between Yb(NO3)3·5H2O and TPPO, however, was a highly symmetrical eight-coordinated complex, in which the Yb(III) centre was coordinated to two bidentate nitrate groups and four TPPO molecules. The geometry in this case is best described as being trans-octahedral, with the two nitrate ligands coordinated practically perpendicular to one another. The complexes isolated from the reactions of lanthanide nitrate salts with the ligand bis(pentamethylene)urea (PMU) had the general formula Ln(PMU)3(NO3)3, where Ln = La – Dy, Yb, Lu. The complexes were found to be nine-coordinated with distorted trigonal prismatic geometry, in which the one base of the prism is composed of the oxygen atoms of the three PMU ligands and the other base is made up by one oxygen atom from each of the bidentate nitrate groups. The second oxygen atoms of each of the nitrate groups protrude upward, occupying capping positions. The reactions of the La and Pr nitrate salts with the ligand 2,2’-dipyridyl-N,N’-dioxide (DPDO) produced two novel complexes of the nature [Ln(DPDO)(H2O)2(NO3)3]. These complexes are remarkable in that their crystal structures reveal the Ln(III) centres to be ten-coordinated. The geometry around the Ln(III) centres was complex, due to the presence of a seven-membered chelate ring, formed by the bidentate coordination of the oxygen atoms from the DPDO ligands to the metal centres. The chelate ring did not lie in a single plane, but was twisted at the pyridyl bridgeheads to lie above and below the coordination plane.
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- Date Issued: 2012
Rhenium complexes with multidentate benzazoles and related N,X-donor (X = N, O, S) ligands
- Authors: Potgieter, Kim Carey
- Date: 2012
- Subjects: Rhenium , Benzimidazoles , Ligands (Biochemistry)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10438 , http://hdl.handle.net/10948/d1020773
- Description: The coordination behaviour of 4-aminoantipyrine (H2pap) and its Schiff base derivatives with the oxorhenium(V) and tricarbonyl rhenium(I) cores are reported. The reactions of trans-[ReOX3(PPh3)2] (X = Cl, Br) with H2pap were studied, and the complexes cis-[ReX2(pap)(H2pap)(PPh3)](ReO4) were isolated. The ligand pap is coordinated monodentately through the doubly deprotonated amino nitrogen as an imide, and H2pap acts as a neutral bidentate chelate, with coordination through the neutral amino nitrogen and the ketonic oxygen. The reactions of trans-[ReOBr3(PPh3)2] and cis-[ReO2I(PPh3)2] with -(2-aminobenzylideneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (H2nap) and 4-(2-hydroxybenzylideneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (Hoap) are also reported. The complexes cis-[Re(nap)Br2(PPh3)]Br, [ReO(OEt)(Hnap)(PPh3)]I and [ReO(OMe)(oap)(PPh3)]I were isolated and structurally characterized. The reactions of the Schiff base derivatives 1,2-(diimino-4’-antipyrinyl)ethane (dae) and 2,6-bis(4-amino-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one)pyridine (bap) with [Re(CO)5X] (X = Br or Cl) produced fac-[Re(CO)3(dae)Cl] and fac-[Re(CO)3(bap)Br] respectively. A series of rhenium(I) tricarbonyl complexes containing bidentate derivatives of aniline was synthesized and structurally characterized. With 1,2-diaminobenzene (Hpda) the ‘2+1’ complex salt fac-[Re(CO)3(κ1-Hpda)(κ2-Hpda)]Br was isolated, but with 2-mercaptophenol (Hspo) the bridged dimer [Re2(CO)7(spo)2] was found. The neutral complex [Re(CO)3(ons)(Hno)] was isolated from the reaction of [Re(CO)5Br] with 2-[(2-methylthio)benzylideneimino]phenol (Hons; Hno = 2-aminophenol), with ons coordinated as a bidentate chelate with a free SCH3 group. In the complex [Re(CO)3(Htpn)Br] (Htpn = N-(2-(methylthio)benzylidene)benzene-1,2-diamine) the potentially tridentate ligand Htpn is coordinated via the methylthiol sulfur and imino nitrogen atoms only, with a free amino group. These rhenium(I) complexes, with the exception of [Re2(CO)7(spo)2], revealed broad emissions centred around 535 nm. The reactions of the rhenium(V) complex cis-[ReO2I(PPh3)2] with 2-aminothiophenol (H2atp), benzene-1,2-dithiol (H2tdt) and 2-hydroxybenzenethiol (H2otp) led to the formation of the rhenium(III) compounds [Re(Hatp)(ibsq)2].OPPh3, [Re(sbsq)3].OPPh3 and [Re(obsq)3].OPPh3 (ibsq = 2-iminothiobenzosemiquinonate, sbsq = 1,2-dithiobenzosemiquinonate, obsq = 2-hydroxothiobenzosemiquinonate) respectively. The complexes adopt a trigonal prismatic geometry around the rhenium centre with average twists angles between 3.20-26.10˚. The E1/2 values for the Re(III)/Re(IV) redox couple were found to be 0.022, 0.142 and 0.126 V for [Re(Hatp)(ibsq)2].OPPh3, [Re(sbsq)3].OPPh3 and [Re(obsq)3].OPPh3 respectively. The reactions of the benzoxazole ligands, 3-(benzoxazol-2-yl)pyridin-2-ol (Hbop) and 5-amino-2-(benzoxazol-2-yl)phenol (Habo) with a [ReO]3+ precursor led to the rhenium(III) complex, [ReCl2(bop)(PPh3)2], and the complex salt, [ReO(abo)I(PPh3)2]ReO4, respectively. A variety of benzothiazole and benzimidazole derivatives were reacted with [Re(CO)5Br]. In the case of bis(benzothiazol-2-ylethyl)sulfide (bts), the neutral complex fac-[Re(CO)3(bts)Br] was obtained. The dimeric complexes (μ-dbt)2[Re(CO)3]2 and (μ-mbt)2[Re(CO)3]2 were formed when 1,3-bis(benzothiazol-2-yl)thiourea (Hdbt) and 1-(benzothiazol-2-ylidene)-3-methylthiourea (Hmbt) were used as ligands. The reaction of 2,2’-(oxybis(methylene))bis(benzimidazole) (bmb) with [Re(CO)5Cl] resulted in the rhenium(I) complex salt fac-[Re(CO)3(bmb)]+, with the tri-μ-chlorohexacarbonyl dirhenate [Re2(CO)6Cl3]- as the counter anion. The neutral complex fac-[Re(CO)3(btp)Cl] was isolated from the reaction of the 2,9-bis(benzothiazol-2-yl)-1,10-phenanthroline (btp) ligand and [Re(CO)5Cl]. The reactions of trans-[ReOCl3(PPh3)2] with bis(benzimidazol-2-ylethyl)sulfide (btn) and 1-(benzothiazol-2-ylidene)-3-methylthiourea (Hmbt) led to the formation of the cationic compounds (μ-O)2[Re2O2(btn)2]I2 and [ReCl2(bte)(PPh3)2]Cl (bte = (benzothiazole-2-yl)-N-ethylidenemethanamine) respectively.
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- Date Issued: 2012
The pump room
- Authors: Krueger, Anton
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225764 , vital:49256 , xlink:href="https://doi.org/10.1080/10137548.2012.754084"
- Description: I like Allan Kolski Horwitz. He’s done great things for independent publishing in South Africa. Through his company, Botsotso, he’s probably responsible for publishing more poetry, prose and drama than any single person in the country today. The industriousness of his one-man operation has generously sponsored and nurtured thousands of pages of local literature over the course of many years. This is why it makes me so uncomfortable to say that I really don’t like this play. It gives me no pleasure to write a negative review, and especially not about books written by people I like. If I hadn’t already committed myself to writing this review, I would have avoided it. Nevertheless, I had, so I won’t.
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- Date Issued: 2012
Curcumin analogues as ligands for Re (I) and (V)
- Authors: Schmitt, Bonell
- Date: 2012
- Subjects: Rhenium , Ligands , Chemistry, Inorganic
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10443 , http://hdl.handle.net/10948/d1020975
- Description: Coordination properties of 4-bromo-N-(diethylcarbamothioyl)benzamide (Hbeb) and 4-bromo-N-(diphenylcarbamothioyl)benzamide (Hbpb) with oxorhenium(V) and rhenium(I) are reported and discussed. Transition metal complexes of these ligands were studied due to the wide range of applications of thiourea derivatives in biological fields. N-[Di(alkyl/aryl)carbamothioyl]benzamide derivatives readily coordinate to metal ions as O,S-donors and the catalytic property of the complexes can be altered by these ligands, due to steric and electronic properties provided by various substituents. The coordination possibilities of curcumin with rhenium(V) are discussed, as well as the difficulties encountered. Analogues of curcumin have been made, which also contains a seven-spacer unit between the phenyl rings, which would be more reactive and more effective in bonding to rhenium and which have greater or a similar biological activity to curcumin. This was done by assessing the coordination properties of 1,5-bis(salicylidene)thiocarbohydrazide (H4salt) and 2,4-bis(vanilidene)thiocarbohydrazide (H4vant) with oxorhenium(V) and rhenium(I) starting materials. Two rhenium(V) complex salts of the core [ReX(PPh3)2]4+ (X = Br, I), containing a coordinated imido nitrogen, are reported. One is a ‘2+1’ complex, coordinating bi- and monodentately, with the other a similar ‘3+0’ complex containing a tridentate imido-coordinated Schiff base. Selected compounds were tested against oesophageal cancer cell lines in order to evaluate and compare their effectiveness in eliminating or reducing the cancer cells in the test medium during biological testing.
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- Date Issued: 2012
Mechanistic studies of unusual Miruta-Baylis-Hillman reactions
- Authors: Nyoni, Dubekile
- Date: 2012
- Subjects: Chemical reactions Benzaldehyde Acrylonitrile Methyl acrylate Coumarins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4400 , http://hdl.handle.net/10962/d1006692
- Description: This study has focussed on the application of synthetic, kinetic and exploratory theoretical methods in elucidating the reaction mechanisms of four Morita-Baylis-Hillman (MBH) type reactions, viz, i) the reactions of the disulfide 2,2'-dithiodibenzaldehyde with various activated alkenes in the presence of DBU and Ph₃P, ii) the reactions of chromone-3-carbaldehydes with MVK, iii) the reactions of chromone-2-carbaldehydes with acrylonitrile and iv) with methyl acrylate. Attention has also been given to the origin of the observed regioselectivity in Michaelis-Arbuzov reactions of 3-(halomethyl)coumarins. Cleavage of the sulfur-sulfur bond of aryl and heteroaryl disulfides by the nitrogen nucleophile DBU has been demonstrated, and a dramatic increase in the rate of tandem MBH and disulfide cleavage reactions of 2,2'-dithiodibenzaldehyde with the activated alkenes, MVK, EVK, acrylonitrile, methyl acrylate and tert-butyl acrylate has been achieved through the use of the dual organo-catalyst system, DBU-Ph₃P – an improvement accompanied by an increase in the yields of the isolated products. Detailed NMR-based kinetic studies have been conducted on the DBU-catalysed reactions of 2,2'-dithiodibenzaldehyde with MVK and methyl acrylate, and a theoretical kinetic model has been developed and complementary computational studies using Gaussian 03, at the DFT-B3LYP/6-31G(d) level of theory have provided valuable insights into the mechanism of these complex transformations. Reactions of chromone-3-carbaldehydes with MVK to afford chromone dimers and tricyclic products have been repeated, and a novel, intermediate MBH adduct has been isolated. The mechanisms of the competing pathways have been elucidated by DFT calculations and the development of a detailed theoretical kinetic model has ensued. Unusual transformations in MBH-type reactions of chromone-2-carbaldehydes with acrylonitrile and methyl acrylate have been explored and the structures of the unexpected products have been established using 1- and 2-D NMR, HRMS and X-ray crystallographic techniques. Attention has also been given to the synthesis of 3-(halomethyl)coumarins via the MBH reaction, and their subsequent Michaelis-Arbuzov reactions with triethyl phosphite. An exploratory study of the kinetics of the phosphonation reaction has been undertaken and the regio-selectivity of nucleophilic attack at the 4- and 1'-positions in the 3-chloro- and 3-(iodomethyl)coumarins has been investigated by calculating Mulliken charges, LUMO surfaces and Fukui condensed local softness functions.
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- Date Issued: 2012
The implacable grandeur of the stranger
- Authors: Krueger, Anton
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229430 , vital:49673 , xlink:href="https://doi.org/10.1080/10137548.2013.799798"
- Description: South Africa is a nation of strangers, an uneasy mishmash of heterogeneous economic groupings, cultures and languages, a nation of marginalised minorities awkwardly pasted together. Numerous attempts have been made by its government to define and bolster a sense of nationalism and to create a sense of cohesion; however, a shadow side of this appeal for national identity has been the rise in xenophobic violence precipitated by the steady influx of refugees into the country. The title of this article is drawn from Albert Camus’s introduction to his disarming novella of dislocation, L’Etranger (1942), and I would like to explore some of the philosophical implications of representing strangers in different ways. Drawing on works by Zygmunt Bauman, Georg Simmel and Julia Kristeva, I will consider ambivalences towards the stranger represented in Magnet Theatre’s production (2010) of Die Vreemdeling [The Stranger], and pose a few questions about our relationship with the unknown. Attempts to familiarise the constituents of various communities with aspects of each other’s strangeness is a project which has typified much South African theatre in the past; and yet this is an approach which stands in sharp contrast to the importance granted processes of defamiliarisation first proposed so succinctly by Victor Shklovsky in 1917. Instead of attempts to harness and explain the unfamiliarity of others in order to communicate diversity, a celebration of the grandeur of the stranger may provide a more enriching alternative.
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- Date Issued: 2012
Employee perceptions of self-employment
- Authors: Gongxeka, Vuyokazi
- Date: 2012
- Subjects: Entrepreneurship -- South Africa , Self-employed -- South Africa , New business enterprises -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9276 , http://hdl.handle.net/10948/1603 , Entrepreneurship -- South Africa , Self-employed -- South Africa , New business enterprises -- South Africa
- Description: The perception that someone has of an entrepreneurial career ultimately influences his/her decision to pursue such a career path. By investigating employees' perceptions of owning a business, this study provides insights regarding the question of why so few South Africans embark on this path. Entrepreneurship is regarded by many as the solution to South Africa’s employment and economic problems. As such, an understanding of the reason why some people become entrepreneurs and others do not could provide solutions on how to stimulate entrepreneurship among all South Africans, and hopefully increase the levels of entrepreneurship in the country. The purpose of the study was to contribute to the field of entrepreneurship by investigating the perceptions and attitudes that employees have regarding an entrepreneurial career, that is, to ask employees what they think having their own business might be like. By investigating these perceptions, the researcher looked for reasons why many individuals remain in the employment of others rather than embarking on an entrepreneurial career, as well as establishing whether these employees had intentions of starting their own businesses, Therefore the primary objective of this study was twofold, namely to establish the perceptions that employees have regarding self-employment, running their own business or following an entrepreneurial career, and to establish the influence of these perceptions on their entrepreneurial intentions. After conducting a comprehensive literature study and examining the various models of intentions, attitude towards the behaviour was identified as having the strongest influence on entrepreneurial intentions. Attitude towards the behaviour is the extent to which an individual makes a favourable or unfavourable evaluation of the behaviour in question, and additionally is a function of beliefs applicable to the behaviour. Attitude towards the behaviour is closely related to perceived desirability, and “desirability” is a form of value. More specifically, work values have the propensity to significantly predict career choice. For the purpose of this study, the 14 work values identified by Farrington et al. (2011) served as the factors to be investigated in establishing the perceptions of an entrepreneurial career. The independent (work values) and dependent (entrepreneurial intentions) variables investigated in this study were defined and operationalised. Reliable and valid items were sourced from existing studies. Respondents were identified by means of convenience and snowball sampling, and a structured questionnaire was made available to the respondents. The data gathered from the 184 usable questionnaires was subjected to various statistical analyses. The validity and reliability of the measuring instrument were confirmed by means of an exploratory factor analysis and calculating Cronbach-alpha coefficients. Descriptive statistics were calculated to summarise the sample data distribution. Pearson’s moment product correlations were calculated to establish the correlations between the various work values and entrepreneurial intentions. Furthermore, a multiple regression analysis was undertaken to investigate whether relationships existed between the perceptions of an entrepreneurial career in terms of several work values and entrepreneurial intentions. The following work values were identified as influencing the entrepreneurial intentions of employees working in small businesses: - Stimulating; - Stability and advancement; - Flexibility; - Autonomy. The more the work values above were perceived to be experienced when following an entrepreneurial career, the more likely it was that the respondents in this study reported intentions of following such a career. In order to investigate the influence of the various demographic variables on the independent and dependent variables, an Analysis of Variance was performed. In addition, the post-hoc Bonferroni test was done to identify significant differences between the means scores of the various categories within each demographic variable. The practical significance of these differences was assessed by means of calculating Cohen’s d. The results showed a significant positive relationship between the demographic variable Population group and the dependent variable Entrepreneurial v intentions. In addition, relationships were identified between Population group and the intrinsic work values Challenging and Stimulating, the extrinsic-related work values Financial benefit and security and Stability and advancement, and the social-related work value Serving the community. A significant positive relationship was also reported between the demographic variable Entrepreneurial parents and the intrinsic-related work value Stimulating, the extrinsic-related work value Future prospects and the social-related work value Serving the community. The demographic variable Age showed a significant positive relationship with the extrinsic-related work value Financial benefit and security. This study has contributed to the field of entrepreneurship research by focusing on employee perceptions of entrepreneurship, and the influence of these perceptions on their intentions to become entrepreneurs. As far as can be established, no other study has adopted this perspective for understanding entrepreneurial behaviour in South Africa or abroad. Furthermore, no study has specifically focused on investigating entrepreneurial intentions among employees of small businesses.
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- Date Issued: 2012
Rhodes University Research Report 2012
- Authors: Rhodes University , Roberts, Jaine , Connan, Verna , Mantolo, Thumeka , Macgregor, Jill , Jacob, Patricia
- Date: 2012
- Language: English
- Type: Text
- Identifier: vital:567 , http://hdl.handle.net/10962/d1011985
- Description: [From Introduction] Rhodes University continued to grow in overall accredited research outputs in 2012, and in other forms of scholarship which enhance the intellectual space of the university. During the graduation ceremonies that followed the 2012 academic year, 2 288 students earned new qualifications. A record 948 students or 41 percent graduated with postgraduate degrees. We also celebrated a new University record of 63 PhD graduates, a wonderful achievement for the smallest university in the country. Our Science Faculty was a particularly noteworthy contributor to the postgraduate numbers, with 35 PhD graduates, 83 Master’s graduates and 132 honours graduates. The University’s Enrolment Plan outlines our intention of becoming a more postgraduate university, and our overall strategy is to enhance our contribution to knowledge production through research and scholarship. Rhodes is well-positioned for such a trajectory, and we look to strengthening our capacity to serve society in this way by striving to provide our academics with effective research support. In the latest Department of Higher Education and Training (DHET) Ministerial Report on National Research Outputs, Rhodes University is listed as having the third most favourable research output rate per capita (the accepted norm for measuring efficiency of investment in the research domain) in the South African university system, and the second highest percentage of academic staff with PhDs (56 percent). Other studies show that Rhodes has the top PhD graduation rate of South African Universities, and very good postgraduate throughput rates overall. We continue to give special attention to identifying potential new postgraduate and research niche areas and programmes, and to developing the appropriate institutional arrangements to effectively support larger numbers of Honours, Masters and Doctoral students, and further enhance their academic and social experiences. The audited result of our DHET submission of accredited research outputs for 2012 has not yet been received at the time of writing, so exact success rates in book and conference submissions are not yet known. These are the smaller components of our overall accredited outputs (in the previous year, books and accredited conference proceedings each contributed 7 percent of our total accredited publishing output, while journals contributed 86 percent). In 2012, Rhodes submitted 46.82 book and book chapter units for consideration (up by 33 percent on the 2011 submission), and 32.04 accredited conference proceeding weighted units (down by 8.6 percent on the 2011 submission, which in turn had been up 46.8 percent on the previous year’s submission).Year-on-year variance on the relatively small submission base in these categories is to be expected. The big component of Rhodes’ publication output, our journal publications, grew by 13.2 percent on the 2011 level to 350.47 units (the previous year has seen a 6 percent increase in this category), maintaining Rhodes’ position amongst the most research productive institutions in the South African Higher Education system. Coupled with Rhodes’ high volume of accredited journal outputs in relation to its size, a very pleasing quality measure is that 90 percent of Journal outputs (the highest proportion in the sector) appear in internationally accredited journal indices. Accredited outputs from thesis-based PhD and Masters graduates rose by 4.9 percent in 2012 to a new high for Rhodes (2011’s figure had grown by 15.4 percent over 2010, which in turn had grown by 35.8 percent over 2009). I add my warm thanks and congratulations to all of our researchers, funders, collaborators and partners who contributed to the excellent accredited research results of 2012, as well as generated the many forms of scholarship that are not counted in the accreditation exercise, but which contribute much to the rich intellectual space that is Rhodes. I also thank all of the administrators who play a crucial role in preparing the university’s meticulous audited submissions.
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- Date Issued: 2012
The symmetry group of a model of hyperbolic plane geometry and some associated invariant optimal control problems
- Authors: Henninger, Helen Clare
- Date: 2012
- Subjects: Geometry , Symmetry groups , Symmetry (Mathematics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5432 , http://hdl.handle.net/10962/d1018232
- Description: In this thesis we study left-invariant control offine systems on the symmetry group of a. model of hyperbolic plane geometry, the matrix Lie group SO(1, 2)₀. We determine that there are 10 distinct classes of such control systems and for typical elements of two of these classes we provide solutions of the left-invariant optimal wntrol problem with quauratic costs. Under the identification of the Lie allgebra .so(l, 2) with Minkowski spacetime R¹̕'², we construct a controllabilility criterion for all left-invariant control affine systems on 50(1. 2)₀ which in the inhomogeneous case depends only on the presence or absence of an element in the image of the system's trace in R¹̕ ²which is identifiable using the inner product. For the solutions of both the optimal control problems, we provide explicit expressions in terms of Jacobi elliptic functions for the solutions of the reduced extremal equations and determine the nonlinear stability of the equilibrium points.
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- Date Issued: 2012
Aspects of heterothermy in four species of afrotropical bats
- Authors: Doty, Anna Catherine
- Date: 2012
- Subjects: Body temperature -- Regulation , Afrotropical mammals , Body temperature , Bats
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10691 , http://hdl.handle.net/10948/d1008402 , Body temperature -- Regulation , Afrotropical mammals , Body temperature , Bats
- Description: Torpor and hibernation, two distinct forms of heterothermy, are physiological responses employed by many endotherms to save energy during periods of cold, climatic unpredictability and food shortage. Heterothermy is characterized by varying body temperature and has been found to occur in various subtropical mammals. However, studies on thermoregulatory capabilities of South African Microchiroptera remain relatively scant. In this study, the capacity for use of heterothermy, the seasonal metabolic rates, and capacity for non-shivering thermogenesis were studied in four species of bats, namely Rhinolophus clivosus, Rhinolophus capensis, Miniopterus natalensis and Myotis tricolor. Animals were collected from a group of three mines in Sleepy Hollow Farm, 30km from Port Elizabeth, South Africa. All species demonstrated bouts of torpor in the winter while R. clivosus interestingly established a high propensity for torpor in the summer and normothermia in the winter. To my knowledge, this is the first study that has shown the down-regulation of metabolism and body temperature in summer and constant maintenance of normothermic body temperature in winter in a species of Microchiroptera. M. natalensis was thermolabile in both summer and winter and body temperatures closely tracked ambient temperatures. Mean ± SD normothermic body temperature measured of wild-caught R. clivosus and M. natalensis was 38.6 ± 1.7°C and 37.3 ± 2.2°C, respectively. Mean torpid body temperature measured of wild-caught R. clivosus, R. capensis and M. natalensis was 22.7 ± 3.3°C, 21.1 ± 3.2 °C, and 22.6 ± 3.1°C, respectively. Non-shivering thermogenesis was measured in R. clivosus and M. natalensis to determine the role of endogenous heat production in a volant mammal. The mean noradrenalineinduced thermogenesis ± SD in R. clivosus and M. natalensis was 2.6 ± 0.8 ml g-1 hr-1 and 2.7 ± 0.6 ml O2 g-1 hr-1, respectively. Both species demonstrated capacity for non-shivering thermogenesis, and this is the first study that has quantified the maximal response to noradrenaline in an Afrotropical Microchiropteran species. Physiology of Afrotropical bats is understudied and the extent to which torpor and/or hibernation is utilized amongst them remains relatively unknown. Heterothermy clearly plays a significant role in the energetic savings and balance of all four species in the study.
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- Date Issued: 2012
Phenotypic plasticity of metabolic rate in an afrotropical bird species (Euplectes orix) across a temperature gradient
- Authors: Van de Ven, Tanja Maria Francisca Nicole
- Date: 2012
- Subjects: Phenotypic plasticity , Evolutionary genetics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10718 , http://hdl.handle.net/10948/d1012659 , Phenotypic plasticity , Evolutionary genetics
- Description: Avian species are known to have the capacity to respond to environmental changes through physiological adjustments. The process whereby organisms adjust their phenotype without genetic change is termed phenotypic plasticity and it is mostly observed to be a phenotypic improvement to ecological challenges. Metabolic rate (MR), which is the rate of energy expenditure in a species, is a highly flexible physiological parameter which results in a great diversity of avian standardised metabolic rates. Like birds from high latitudes, Afrotropical bird species are expected to have the capacity to adjust their energy expenditure to match the availability of resources. Previous studies on the flexibility of physiological parameters in birds have focused on the magnitude of change of physiological adjustments and the cues inducing these changes. Comparative research has furthermore investigated metabolic rates across aridity, altitude, latitude and temperature gradients. Recently, a clear dichotomy has become evident with elevated metabolic rates observed in high latitude birds in winter and a down-regulation of metabolic rates observed in birds exposed to low latitude mild winters. In this study, the shape of the reaction norm, the magnitude, the reversibility, the direction and the rate of change of two physiological parameters, basal metabolic rate (BMR) and summit metabolic rate (Msum), were investigated in a coastal and an inland population of Southern Red Bishops (Euplectes orix) through seasonal acclimatisation and laboratory acclimation. Summer and winter basal metabolic rates as well as body mass, were highly flexible traits in free-ranging coastal and inland Red Bishops. Birds acclimatised to a mild coastal climate in winter exhibited reduced basal and summit metabolic rates, whereas birds originating from a more variable inland climate increased basal metabolic rate in winter, but did not show increases of Msum in winter. Red Bishops responded to short term thermal acclimation under laboratory conditions by gradually changing body mass. Acclimation periods of 21 days revealed a negative relationship between body mass and acclimation air temperature. Peak responses of basal metabolic rate to ambient temperature change were observed in both coastal and inland birds between two and eight days after the change in acclimation air temperature. The influences of seasonal acclimatisation on energy expenditure differed between coastal and inland birds, however, during laboratory acclimation individuals from the two populations showed no difference in response. Within the individuals of the coastal and inland Southern Red Bishops, phenotypic flexibility is observed in body mass, basal metabolic rate and summit metabolic rate as a response to environmental changes. This flexibility is thought to increase thermoregulatory capacities of the Southern Red Bishop in different habitats and climates.
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- Date Issued: 2012
Comparative in-vitro activities of trimethoprimsulfamethoxazole and the new fluoroquinolones against confirmed extended spectrum beta-lactamase producing Stenotrophomonas maltophilia in Nkonkobe Municipality, Eastern Cape environment
- Authors: Adeyemi, Oluwatosin Oluwakemi
- Date: 2012
- Subjects: Antibiotics , Microbial sensitivity tests , Drug resistance in microorganisms , Pathogenic microorganisms , Gram-negative bacterial infections
- Language: English
- Type: Thesis , Masters , MSc (Microbiology)
- Identifier: vital:11275 , http://hdl.handle.net/10353/d1007576 , Antibiotics , Microbial sensitivity tests , Drug resistance in microorganisms , Pathogenic microorganisms , Gram-negative bacterial infections
- Description: Stenotrophomonas maltophilia is increasingly emerging as an opportunistic pathogen of global concern. Due to its inherent resistance to several classes of antibiotics including carbapenems and its ability to acquire mobile resistance elements, treatment of infections caused by S. maltophilia is a constant challenge for clinicians. Trimethoprim-sulphamethoxazole (TMP-SMX) is the generally accepted antibiotic of choice for the treatment of infections caused by this organism, but resistance to the drug is increasingly being reported; hence, the need for alternative therapeutic options. In this study, the antimicrobial susceptibility profile of 110 commensal S. maltophilia isolates obtained from Nkonkobe municipality, Eastern Cape Province, Republic of South Africa was investigated. Twenty-one antibiotics including TMP-SMX and the newer fluoroquinolones; levofloxacin, gatifloxacin and moxifloxacin were included in the antibiotic panel. About 63.4 percent of the isolates were susceptible to TMP-SMX with a resistance rate of 28.2 percent. The fluoroquinolones were more effective with susceptibilities ranging from 76 percent to 94.7 percent. Resistance to the fluoroquinolones ranged from 1.3 percent to 2.7 percent. Levofloxacin was the most effective fluoroquinolone tested. Phenotypic dectection of extended spectrum β-lactamases (ESBLs) showed double disc synergy test (DDST) positivity in 59.5 percent of the isolates. Cefepime was the most sensitive indicator cephalosporin in the DDST with 77.3 percent of suspected ESBL-producing isolates showing cefepime-clavulanic acid synergy. Isolates exhibited nine different ESBL phenotypes, however, PCR amplification of the bla genes revealed four isolates that possessed genes belonging to the CTX-M group (CTX-M-1 and CTX-M-8 groups). ESBL genes are usually carried on mobile elements such as plasmids and transposons which may also bear genes that mediate resistance to aminoglycosides, tetracyclines, TMP-SMX and fluoroquinolones. ESBL positive isolates appeared more susceptible to the fluoroquinolones compared to TMP-SMX but there was no significant relationship between ESBL production and susceptibility to these drugs (p > 0.05). The newer fluoroquinolones are a possible alternative treatment option for S. maltophilia infections in this environment but further studies and clinical investigations are needed to determine the in vivo efficacy of these drugs.
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- Date Issued: 2012
Commensal bacteria belonging to the Staphylococcus Acinetobacter and Stenotrophomonas genera as reservoirs of antibiotic resistance determinants in the environment of Nkonkobe Municipality, Eastern Cape Province , South Africa
- Authors: Adegoke, Anthony Ayodeji
- Date: 2012
- Subjects: Acinetobacter infections , Drug resistance in microorganisms , Staphylococcal infections , Bacterial diseases
- Language: English
- Type: Thesis , Doctoral , Degree
- Identifier: http://hdl.handle.net/10353/6539 , vital:30551
- Description: A study to assess the potentials of some commensal bacteria that belong to Staphylococcus, Acinetobacter and Stenotrophomonas genera as reservoirs of antibiotic resistance determinants in the environment of Nkonkobe Municipality of the Eastern Cape Province, South Africa, was carried out using standard microbiological and molecular techniques. A total of 120 Staphylococcus isolates which consisted of Staphylococcus haemolyticus (30%), Staphylococcus aureus (23.3%) from pig; Staphylococcus capitis (15%) from goat; Staphylococcus heamolyticus (5%) and Staphylococcus xylosus (15%) from cattle and other Staphylococci (11%) from dead chicken and pigs were isolated. About 23.3% of these isolates were coagulase positive and 76.7% were coagulase negative. This difference in prevalence along coagulase production divide was statistically significant (p < 0.05). Eighty-six Acinetobacter species (Acinetobacter baumannii/calcoaceticus and Acinetobacter haemolyticus) were also isolated from Alice and Fort Beaufort towns samples, while 125 Stenotrophomonas maltophilia isolates were from grass root rhizosphere (96%) and soil butternut root rhizosphere (4%). Between 75-100% of the Staphylococccus species were resistant to Penicillin G, tetracycline, sulphamethaxole and nalidixic acid; about 38 % were methicillin resistant, consisting of 12.6% methicillin resistant Staphylococcus aureus (MRSA) from pig and a total of 12% vancomycin resistant were observed. Also, 12% of the isolates were erythromycin resistant while 40.2 % were resistant to the third generation cephalosporin, ceftazidime. The antibiotic resistance genes vanA, VanB, eryA, eryB, eryC were not detected in all the phenotypically resistant Staphylococccus species, but mec A gene and mph genes were detected. In the Acinetobacter species, a wide range of 30-100% resistance to penicillin G, ceftriazone, nitrofurantoin, erythromycin, and augmentin was observed. Polymerase chain reaction (PCR) revealed the presence of Tet(B) and Tet(39) genes in these species, while Tet (A), Tet(M) and Tet(H) were absent. Also, 9.3% of the Acinetobacter species showed phenotypic production of extended spectrum beta lactamases (ESBLs) while 3.5% were positive for the presence of blaCTX-M-1 genes. The Stenotrophomonas maltophilia isolates showed varying resistance to meropenem (8.9%), cefuroxime (95.6 %), ampicillin-sulbactam (53.9%), ceftazidime (10.7%), cefepime (29.3 %), minocycline (2.2%), kanamycin (56.9%), ofloxacin (2.9%), levofloxacin (1.3%), moxifloxacin (2.8%), ciprofloxacin (24.3%), gatifloxacin (1.3%), polymyxin B (2.9 %), cotrimoxazole (26.1%), trimethoprim (98.6%), aztreonam(58%) and Polymyxin B (2.9 %). The isolates exhibited significant susceptibility to the fluoroquinolones (74.3-94.7 %), polymycin (97.1%) and meropenem (88.1%). Only sul3 genes were the only sulphonamide resistance gene detected among the trimethoprim-sulphamethoxazole resistant isolates. The observed multiple antibiotic resistance indeces (MARI) of >2 for Staphylococcus species, Acinetobacter species and Stenotrophomonas maltophilia suggest that they have arisen from high-risk sources where antibiotics are in constant arbitrary use resulting in high selective pressure. The presence of tetracycline resistance genes in Acinetobacter species justifies the observed phenotypic resistance to oxytetracycline and intermediate resistance to minocycline. High phenotypic resistance and the presence of some resistance genes in Staphylococcus species is a possible threat to public health and suggests animals to be important reservoirs of antibiotic resistance determinants in the environment. Indiscriminate use of antibiotics induces this kind of antibiotic resistance and should be discouraged. Personal hygiene is encouraged as it reduces the load of Acinetobacter species contacted from the environment that may be difficult to control. Commensal Stenotrophomonas maltophilia are as important as their clinical counterparts due to their roles in opportunistic infection, antibiotic resistance and their associated genes, especially sul gene. Personal hygiene is hereby advocated especially when in contact with soil, plants and plants’ rhizospheric soil.
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- Date Issued: 2012
Discrimination against women under customary law in South Africa with reference to inheritance and succession
- Authors: Mashalaba, Siyabulela Welcome
- Date: 2012
- Subjects: Inheritance and succession -- South Africa , Customary law -- South Africa , Sex discrimination -- South Africa
- Language: English
- Type: Thesis , Masters , MA (Human Rights)
- Identifier: vital:11099 , http://hdl.handle.net/10353/505 , Inheritance and succession -- South Africa , Customary law -- South Africa , Sex discrimination -- South Africa
- Description: In South Africa, it is evident that women are uniformed of their essential human rights, especially their inheritance and succession rights, including protection of such rights. Human rights are international norms that protect individuals everywhere from the states’ political, legal and social abuse. Human rights are entitlements which human beings have in order to enhance their human condition. They are the fundamental entitlements or minimum standards to be met for individual so that they live with dignity. This study focused on discrimination of women under customary law in South Africa with reference to inheritance and succession. The study validated the findings of other researchers on the impact of cultural practices on women’s rights to inheritance and succession. In addition the findings revealed that efforts t eliminate traditional practices, should foremost come from men and from communities that hold such destructive attitudes towards women. The outcomes and recommendations of this study would assist the government and other institutions to adopt effective measures to empower women and especially educate them so that they can assert and defend their human rights
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- Date Issued: 2012
Determinants of customer satisfaction and retention: a survey of the banking industry in Kenya
- Authors: Mburu, Peris Njoki
- Date: 2012
- Subjects: Banks and banking -- Customer services -- Kenya , Consumer satisfaction -- Banks and banking -- Kenya , Customer relations -- Management -- Kenya
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8787 , http://hdl.handle.net/10948/d1014106
- Description: Customers have become the lifeblood of any organisation. Without customers, or-ganisations would not exist let alone survive in this competitive global environment (Grigoroudis, Politis and Siskos, 2002). Banks depend on sufficient and sustaining profitability to survive in the global business world. Customers are the source of banks‟ profitability. By satisfying the customer, the bank is able to retain the custom-er and reap maximum benefits from the relationship which ultimately leads to higher profitability. Customer satisfaction has therefore evolved as a strategic business ini-tiative which banks cannot ignore. Retention of the bank customer has become one of the most important objectives of the overall marketing strategy of any bank. In Kenya, the term „customer service‟ came to the fore just over fifteen years ago when banks started acquiring customer service departments. Since then, many cus-tomer training programs for staff have been put in place to transform the image of the customer as not just a profit-maker for the banks but as a human being with needs, which if not fulfilled will cause the customer to look for alternatives in the market. Training has focused on the bank staff whose customer handling skills have been sharpened. In spite of this, no empirical study has attempted to find out if the intended satisfaction of the customer has been achieved or not, which is indicative of little or no attention being given to this important phenomenon. In Africa, with the ex-ception of South Africa, empirical studies on customer satisfaction in the banking in-dustry are few. This gap presented the motivation for this study. The primary objective was to establish the determinants of customer satisfaction and retention in the Kenyan banking industry. The secondary objectives were to establish the relationship between socio-economic factors and customer satisfaction in Ken-yan banks; secondly, to determine whether bank-related factors influence customer satisfaction in Kenyan banks; thirdly, to identify the various strategies known to cus-tomers and employed by Kenyan banks to ensure customer satisfaction and customer retention and finally, to analyse the relationship between customer satisfaction and customer retention in Kenyan banks. The study adopted a descriptive survey design to suit the target population which was dispersed over a wide geographical region spanning the entire Kenya. The tar-get population included every bank customer in Kenya. Both qualitative and quantita-tive data were used. The data collection instrument was a self-administered ques-tionnaire that contained both closed and open-ended questions. Statistical tests were done using Pearson, Chi Square, Anova, Pearson Correlation and Multi-linear re-gression. Data were presented using frequency distribution tables, percentages, cross tabulation and pie charts. The findings indicated a positive relationship be-tween bank-related factors and customer satisfaction and retention. The conclusion was that if banks improved on factors like quality service, staff orientation towards customers, availability of management and ATM uptimes just to name a few, propor-tionately, customer satisfaction and retention would be enhanced. Finally, recommendations based on the findings were made to the Kenyan banks highlighting antecedents which would enhance the customers‟ satisfaction and reten-tion in the Kenyan banking industry.
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- Date Issued: 2012
Feeding dynamics of suspension-feeders in the nearshore marine environment adjacent to two contrasting estuaries in the Eastern Cape, South Africa
- Authors: Vermeulen, Ilke
- Date: 2012
- Subjects: Suspension feeders -- South Africa -- Eastern Cape , Suspension feeders -- Food -- South Africa -- Eastern Cape , Coastal organisms -- South Africa -- Eastern Cape , Streamflow -- South Africa -- Eastern Cape , Tetraclitidae -- South Africa -- Eastern Cape , Mexilhao mussel -- South Africa -- Eastern Cape , Polychaeta -- South Africa -- Eastern Cape , Estuarine health -- South Africa -- Eastern Cape , Estuaries -- Freshwater inflow -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5916 , http://hdl.handle.net/10962/d1016242
- Description: Coastal transition zones form important interlinking regions where marine ecosystems, rivers and estuarine environments significantly influence each other. Coastal rocky shores are key habitats that sustain a variety of primary producers and invertebrates and due to the dynamic nature of coastal ecosystems, suspension-feeders on rocky shores can be influenced by an array of autochthonous and allochthonous food sources. Fatty acid and stable isotope trophic markers were employed to distinguish between regional and temporal changes in the potential food sources to rocky shore suspension-feeders in the Eastern Cape Province of South Africa. The primary aim was to assess the spatial and temporal influences of contrasting river flows on the available food sources to three indigenous coastal suspensionfeeders, namely the volcano barnacle Tetraclita serrata, brown mussel Perna perna and tubebuilding polychaete Gunnarea capensis. This was done by examining the intra- and interspecific changes in the fatty acid and stable isotope signatures of the barnacles, mussels and polychaetes in the adjacent marine environment of a freshwater-restricted (Kariega) and freshwater-dominated (Great Fish) estuary during austral summer and winter. Multivariate and Kruskal-Wallis analyses of variance on the fatty acid and isotopic signatures, respectively, identified significant regional changes in the barnacles and mussels, while only stable isotopes distinguished between the Kariega and Great Fish polychaetes (P < 0.05). In addition, significant temporal changes were observed in consumer fatty acids and isotope values in both regions (P < 0.05). Bacterial sources, detritus and phytoplankton assemblages, which are influenced by hydrology and vegetation, differed between regions and were mainly responsible for the regional and temporal separations. Principal component analyses on the consumer fatty acid signatures distinguished between animals situated upstream (i.e. north) and downstream (i.e. south) of the Kariega Estuary mouth in summer. The north/south separation was mainly due to greater contributions of diatoms to northernlocated animals and dinoflagellates and detritus to southern-located consumers. In addition, the south-flowing Agulhas Current on the eastern shores of southern Africa appeared to influence the north/south separation in the Kariega region, as water leaving the estuary was probably entrained into the south-easterly flowing currents, thereby depositing estuarinederived detritus to southern populations. In general, diatoms and detritus were essential food sources to the filter-feeders in summer, and flagellates, diatoms, zooplankton and detritus were important in winter. Coastal macroalgae was a key food source in the Kariega and Great Fish regions during both seasons. Consistently large levels of diatom markers (16:1n-7 and 20:5n-3) and dinoflagellate markers (22:6n-3) in consumer tissues in the Kariega and Great Fish regions identified that phytoplankton was their dominant food source. The barnacles, mussels and polychaetes had similar fatty acid markers and a fairly narrow δ¹³C range (-16.5 to -14.4 ‰), suggesting that they probably consumed similar food. Carbon isotope analyses, however, separated the suspension-feeders into slightly depleted (barnacles; -16.5 to -16.1 ‰), intermediate (mussels; -15.8 to -15.0 ‰) and enriched (polychaetes; -15.0 to -14.4 ‰) consumers, but did not provide conclusive evidence of their preferences for specific phytoplankton. Conversely, fatty acid analyses highlighted that barnacles and mussels had greater proportions of dinoflagellate markers (22:6n-3; 7.0-15.3 % TFA), while polychaetes had larger diatom levels (20:5n-3; 15.1-22.2 % TFA). In addition, all three species had consistently large contributions from bacterial fatty acids (15:0, i-16:0, 17:0 and i-18:0; 4.2-13.6 % TFA) in summer and winter, and large proportions of saturated fatty acids (33.3-53.1 % TFA) including those with 14 to 18 carbons, indicating that bacterial and detritus food sources played an important role in their diets. Barnacles had small levels of terrestrial markers (18:2n-6 and 18:3n-3; <2.5 % TFA) and demonstrated increased omnivorous feeding compared with the other suspension-feeders [increased levels of 20:1n-11 and 20:1n-9, higher 18:1n-9/18:1n-7 ratios at ~2.1, enriched δ¹⁵N values at ~10.6 ‰; zooplankton (potentially including microzooplankton, larvae and protists) contribution of up to 61 % of the diet]. Mussels contained significant proportions of the terrestrial markers (18:2n-6 and 18:3n-3; >2.5 % TFA) and exhibited intermediate omnivory (intermediate levels of 20:1n-11 and 20:1n-9, intermediate 18:1n-9/18:1n-7 ratios at ~1.3, less enriched δ¹⁵N values at ~7.9 ‰; zooplankton contribution of 10-15 % of the diet). The more depleted nitrogen signatures in the mussels relative to the barnacles and polychaetes possibly illustrated a stronger preference for autotrophic food. Polychaetes mainly consumed plant food sources (i.e. microalgae, macroalgae and detritus; high levels of i-18:0, 18:1n-9, 18:4n-3 and 20:5n-3) and displayed little omnivory (low levels of 20:1n-11 and 20:1n-9, low 18:1n-9/18:1n-7 ratios at ~0.4, intermediate δ¹⁵N values at ~9.1 ‰; zooplankton contribution of <10 % of the diet). The barnacles, mussels and polychaetes are all suspension-feeders, originally presumed to consume the same food sources. The variations observed among the species, therefore, may result from differences in the proportional contributions of the various food sources to their diets as well as distinctions in metabolism. The distinct changes in the fatty acid and stable isotope signatures in all three filter-feeders in the Kariega and Great Fish regions are likely influenced by the diversity in regional vegetation and hydrology in the different systems, combined with interspecific differences in resource partitioning among the species.
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- Date Issued: 2012
Touching Brýnstone
- Authors: Woudstra, Ruth
- Date: 2012
- Subjects: South African fiction (English) -- 21st century , Short stories, South African (English) -- 21st century , South African poetry (English) -- 21st century , Creative writing (Higher education) , Diaries -- Authorship , English language -- Writing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2504 , http://hdl.handle.net/10962/d1015032
- Description: Touching Brýnstone is the story of Beth, a young journalist who is troubled by misfortunes in her family and work circumstances. In a Pretoria library she is seduced by a book that consoles her and progressively becomes a fetish object. It sparks a journey to Japan, where she arrives to teach English. She is intent on meeting the author, whom she confounds with protagonist and book. This Bildungsroman is an exploration of the complex relationship between inner and outer self, and the struggle towards wholeness. Beth must find a way out of the obsession so that she can return to South Africa with an enriched insight into her shadow self.
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- Date Issued: 2012
Nanocomposites of nickel phthalocyanines as electrocatalysts for the oxidation of chlorophenols an experimental and theoretical approach
- Authors: Khene, Mielie Samson
- Date: 2012
- Subjects: Nanocomposites (Materials) -- Research Phthalocyanines -- Research Chlorophenols -- Research Electrocatalysis -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4326 , http://hdl.handle.net/10962/d1004986
- Description: In this work the interaction between peripherally (b) substituted nickel tetrahydroxyphthalocyanines (b-NiPc(OH)4 and poly-b-Ni(O)Pc(OH)4) with 4-chlorophenol is theoretically rationalized by performing calculations at the B3LYP/6-31G(d) level. Density functional theory (DFT) and molecular orbital theory are used to calculate the condensed Fukui function for phthalocyanine derivatives and 4-chlorophenol, in order to determine the reactive sites involved when 4-chlorophenol is oxidized, and to compare theoretically predicted reactivity to experimentally determined electrocatalytic activity. Electrocatalytic activities of adsorbed NiPc derivatives: OPGE-α-NiPc(OH)8 (OPGE = ordinary pyrolytic graphite electrode, α = nonperipheral substitution), OPGE-a-NiPc(OH)4 and OPGE-β- NiPc(OH)4 are compared with those of the polymerized counterparts: OPGE-poly-α-Ni(O)Pc(OH)8, OPGE poly-a-NiPc(OH)4 and OPGE-poly-β-NiPc(OH)4, respectively. β-NiPc(NH2)4, β-NiPc(OH)4, α-NiPc(OH)4, α-NiPc(OH)8, α-NiPc(C10H21)8 are adsorbed on singled walled carbon nanotube (SWCNT) and β-NiPc(NH2)4-SWCNT (linked to SWCNT), are used to modify glassy carbon electrode (GCE) and employed for the electro oxidation of chlorophenols. The β-NiPc(NH2)4-SWCNT gave the best current response for the oxidation of 4-chlorophenol. α-NiPc(OH)8-SWCNT and α-NiPc(C10H21)8 gave the best resistance to electrode fouling due to oxidation by product of 4-chlorophenol. The synthesis of conjugates of cadmium telluride quantum dots (CdTe-QDs) capped with thioglycolic acid and peripherally substituted nickel tetraamino phthalocyanine (β-NiPc(NH2)4) complex were also employed for the oxidation of chlorophenols. Separation of one of the diastereomers of 1, 2-subnaphthalocyanine (SubNPc) was achieved as well as separation of the enantiomers. The absorption and magnetic circular dichroism spectra, together with theoretical calculations, reveal rather small variations in the frontier molecular orbitals of the SubNPc compared to conventional subphthalocyanine (SubPc), except for the destabilization of the highest occupied molecular orbital (HOMO), which results in a characteristic absorption in the Soret band region. The chirality of SubNPc, including the cyclic dichroism (CD) signs and intensities, are discussed in detail.
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- Date Issued: 2012
A study of four-dimensional oscillator groups and the associated left-invariant control affine systems
- Authors: Biggs, Rory
- Date: 2012
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164941 , vital:41186
- Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Mathematics, 2012
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- Date Issued: 2012