Synthesis, photochemical and photophysical properties of gallium and indium phthalocyanine derivatives
- Authors: Chauke, Vongani Portia
- Date: 2008
- Subjects: Phthalocyanines , Photochemotherapy , Electrochemistry , Gallium , Indium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4375 , http://hdl.handle.net/10962/d1005040 , Phthalocyanines , Photochemotherapy , Electrochemistry , Gallium , Indium
- Description: The syntheses of octasubstituted and unsusbstitituted Gallium(III) chloride and indium(III) chloride phthalocyanines (GaPc and InPc), their photophysical, photochemical and nonlinear optical parameters are hereby presented. The photocatalytic oxidation of 1-hexene using the synthesized GaPc and InPc complexes as well as electrochemical characterization is also presented in this thesis. Fluorescence quantum yields do not vary much among the four Ga complexes, except for complex 21c; therefore it was concluded that the effect of substituents is not significant among them. Solvents however, had an effect on the results. Lower Φ[subscript F] values were obtained in low viscosity solvents like toluene, relative to highly viscous solvents, such as DMSO. The triplet quantum yields were found to be lower in DMSO than in DMF and toluene. The rate constants for fluorescence, intersystem crossing and internal conversion as well as fluorescence and triplet lifetimes are reported. Photodegradation and singlet oxygen quantum yields have also been reported. There was no clear correlation between the latter parameters. It was however established that the four gallium MPcs were stable, within the allowed stability range for phthalocyanines. High quantum yields of triplet state (Φ[subscript T] ranging from 0.70 to 0.91 in dimethysulfoxide, DMSO) and singlet oxygen generation (Φ[subscript greek capital letter delta], ranging from 0.61 to 0.79 in DMSO) were obtained. Short triplet lifetimes 50 to 60 μs were obtained in DMSO). Calculated non-linear parameters of these complexes are compared with those of the corresponding GaPc derivatives and tetrasubstituted GaPc and InPc complexes. The optical limiting threshold intensity (I[subscript lim]) values for the InPc and GaPc derivatives were calculated and compared with those of corresponding tetrasubstituted InPc and GaPc complexes. The octasubstituted were found to be better optical limiters. Photocatalytic oxidation of 1-hexene by GaPc (21a-c) and InPc (22a-c) derivatives is also presented. The photocatalytic oxidation products for 1-hexene were 1,2- epoxyhexane and 1-hexen-3-ol. The % conversion values of 1-hexene and % selectivity of 1,2-epoxyhexane were generally higher for InPc derivatives. Even though InPc derivatives showed better photocatalytic results than GaPc derivatives, the former were less stable relative to the latter. Both type I and type II mechanism were implicated in the photocatalysis mechanism.
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- Date Issued: 2008
Synthesis, photophysics and electrochemical study of tin macrocycles
- Authors: Khene, Mielie Samson
- Date: 2008
- Subjects: Electrochemistry , Photochemistry , Phthalocyanines , Macrocyclic compounds , Spectrum analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4376 , http://hdl.handle.net/10962/d1005041 , Electrochemistry , Photochemistry , Phthalocyanines , Macrocyclic compounds , Spectrum analysis
- Description: Three non-peripherally substituted tin(IV) macrocylic compounds, octahexylphthalocyaninato dichlorotin(IV) (35a), octahexyltetrabenzo-5,10,15-triazaporphyrinato dichlorotin(IV) (35b) and octadecylphthalocyaninato dichlorotin(IV) (35c) were synthesized and their photophysical and electrochemical behaviour studied. Complex (35b), containing a CH group in place of one of the aza nitrogen atom of the phthalocyanine core, shows a split Q band due to its lower symmetry. The triplet state quantum yields were found to be lower than would be expected on the basis of the heavy atom effect of tin as the central metal for phthalocyanine derivatives (35a and 35c). In contrast, (35b) shows a triplet quantum yield ΦT = 0.78. The triplet state lifetimes were solvent dependent, and were higher in THF than in toluene. Cyclic voltammetry and spectroelectrochemistry of the complexes revealed only ring based redox processes. This thesis also reports on the microwave syntheses of tetrasulphonated tin phthalocyanine and tetrasulphonated tin α,β,γ-tetrabenzcorrole. The latter was only formed at low ratios (< 1:8) of 4-sulfophthalic acid to urea. Both complexes are aggregated in aqueous media, but can be partly or fully disaggregated by the addition of Triton X-100. The SnTSTBC complex has lower triplet life times and yields, while binding constant and quenching (of bovine serum albumin) constant are lower for SnTSTBC, compared to SnTSPc. Finally Non-peripherally (α) tetra- (40) and octa-(38a) substituted dodecyl-mercapto tin(IV) phthalocyanines where synthesized and the electrochemical behavior studied. Cyclic voltammetry and spectroelectrochemistry show ring-based reductions for (38a) and (40); the former shows two ring oxidations, while the latter shows only one ring based oxidation. The adsorption kinetics of (38a) and (40) on a gold electrode have been investigated by electrochemical impedance spectroscopy (EIS). The equilibrium constant (K) for the adsorption and the Gibbs free energy ΔG(ads) of the self-assembled monolayer (SAMs) were evaluated based on the Frumkin isotherm. The interaction factor between adsorbate –adsorbate molecules is also discussed.
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- Date Issued: 2008
Synthetic, spectrometric and computer modelling studies of novel ATP analogues
- Authors: Gxoyiya, Babalwa Siliziwe Blossom
- Date: 2008
- Subjects: Spectrum analysis Tuberculosis -- Treatment Chemotherapy Adenosine triphosphate Adenosine triphosphate -- Synthesis Adenosine triphosphate -- Computer simulation Adenosine triphosphate -- Spectrometric imaging Glutamine synthetase Tuberculosis -- Chemotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4386 , http://hdl.handle.net/10962/d1005051
- Description: This study has been concerned with the design and synthesis of A TP analogues with the potential to act as inhibitors of glutamine synthetase - a novel target for therapeutic intervention in the treatment of tuberculosis. Using a structural -analogy approach, various 3-indolylalkanoic acid, benzimidazole and pyrazolo[3,4-dJpyrimidine derivatives have been prepared and characterized. Alkylation of the heterocyclic bases using 4-(bromomethyl)-2,2-dimethyl-1 ,3-d ioxolane, 2-(bromomethoxy)ethyl acetate and 2-(chloroethoxy)ethanol in the presence of either NaH or BulOK afforded the corresponding N-alkylated derivatives of benzimidazole and 4-aminopyrazolo[3,4-dJpyrimidine (4-APP). Similar reactions with 3-indo lylalkanoic esters resulted in O-alkyl cleavage with the formation of new esters. Alkylation of benzimidazole with allyl bromide, 4-bromobutene and 2-methylbut-2-ene has also been shown to afford the corresponding l-alkenylbenzimidazoles in moderate to excellent yield (43-96%). Subsequent oxidation of these products using CTAP, gave the dihydroxy derivatives in poor to good yields (26-77%). Phosphorylation of various hydroxy derivatives of benzimidazole and 4-APP has been achieved using diethyl chlorophosphate to afford the corresponding monophosphate and 1,2-diphosphate esters. Glycosylation of each of the heterocyclic bases has been successfully achieved using 1,2,3,4,6-penta-O-acetyl-D-glucopyranose and SnCl4 in acetonitri le, while methanolysis of the resulting tetraacetates, using methanolic NaOMe, afforded the hydroxy derivatives in good yield (50-70%). Various 1- and 2-dimensional NMR spectroscopic methods (e.g., IH, 13C, lip, COSY, HSQC and HMBC) have been used to confirm the structures of the synthesized A IP analogues. The application of NMR prediction programmes has been explored, permitting assessment of their agreement with the experimental data and confirmation of assigned structures. High-resolution electron impact (EI) mass spectrometric data have been used to explore the mass fragmentation pathways exhibited by selected derivatives, and certain common fragmentations have been identified. Molecular modelling of selected products as potential glutamine synthetase ligands has been performed on the Accelrys Cerius2 platform, and interactive receptor-ligand docking studies have been conducted using the Ligand-Fit module. These studies have revealed possible hydrogen-boding interactions between the selected analogues and various amino acid residues in the glutamine synthetase active site.
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- Date Issued: 2008
Teachers' perceptions of participative management in a primary school in Namibia
- Authors: Kambonde, Samuel Angaleni
- Date: 2008
- Subjects: Education, Elementary -- Namibia Teachers -- Namibia School management and organization -- Namibia Educational leadership -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1795 , http://hdl.handle.net/10962/d1003680
- Description: Participative management, a key theme in contemporary management literature, is one of the central aims of the decentralization policy in Namibian education. Current perceptions of participative management on the part of teachers in Namibia are therefore of topical interest. This study set out to explore such perceptions among teachers in a Namibian primary school. The study is an interpretive case study focusing on six individual teachers’ understanding and experience of participative management within their place of work, a primary school in the Oshikoto region of Namibia. Semi-structured interviews, observation and document analysis were used to gather data. The study revealed a strong sense of commitment among the respondents to participative management and its accompanying practices, such as shared decision making and broad stakeholder involvement. Participative management was implemented chiefly through a committee structure for school organisation and government. Respondents also highlighted challenges facing participative management, such as the persistence of autocratic leadership, conflicts of interest in decision making, laziness and unwillingness among staff members, and a lack of understanding among parents concerning their role in the schooling of their children. HIV/AIDS was also seen to pose challenges to the free and frequent participation of stakeholders. The chief recommendation arising from these findings is that school leaders and managers’ understanding of tenets of participative management, such as site-based management and democratic management approaches, requires improvement and development.
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- Date Issued: 2008
Teaching reading in grade 4 Namibian classrooms : a case study
- Authors: Mutenda, Josephine
- Date: 2008
- Subjects: Literacy -- Study and teaching (Elementary) -- Namibia English language -- Study and teaching (Elementary) -- Namibia Reading (Elementary) -- Namibia Second language acquisition
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1797 , http://hdl.handle.net/10962/d1003682
- Description: Literacy is currently a topic of great concern in Namibia. Learners in this country have difficulty in reading and writing, and are often functionally illiterate. This study focuses on the beliefs, experiences and practices of teachers of reading in English to second language learners in Grade 4. Grade 4 is the transitional grade from mother tongue to English as the medium of instruction. The switch to English makes teaching reading in that language especially challenging. The study is structured according to the case study mode of enquiry, with the target respondents comprising Grade 4 teachers. Classroom observation, interviews and document analysis were used as means of collecting data. The main findings revealed that beliefs and experience had an impact on the way in which reading was taught in this study. It emerged that the teachers’ childhood experiences of literacy and learning to read are perpetuated in their beliefs, their attitudes, their basic conceptualization of reading and their current practices, all of which directly affect the children in their classes. Although the teachers’ professional training also had some influence on their teaching methods, neither of the two teachers interviewed had received much in-service support on how to teach reading, and they depended to a large extent on their recall of how they had learned to read themselves. Both teachers were taught in a traditional, teacher-centered way, involving phonics, rote-learning and drilling. Because they see themselves as competent readers, they believe that these approaches were effective and worth sustaining. Tentative recommendations arising from analysis of the data indicate possible areas for improvement in the teaching of reading, and offer guidelines to help teachers cope with the challenge.
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- Date Issued: 2008
Temperature dependence of the HartRAO pointing model
- Authors: Copley, Charles Judd
- Date: 2008
- Subjects: Astronomical instruments , Observatories -- South Africa , Telescopes , Astronomical observatories , Astronomy -- Data processing , Antennas (Electronics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5491 , http://hdl.handle.net/10962/d1005277 , Astronomical instruments , Observatories -- South Africa , Telescopes , Astronomical observatories , Astronomy -- Data processing , Antennas (Electronics)
- Description: This thesis investigates control aspects of the Hartebeeshoek Radio Astronomy Observatory (HartRAO) antenna. The installation of a new 22 GHz receiver has required the pointing accuracy to be improved to less than 4 mdeg. The effect of thermal conditions on the the HartRAO antenna pointing offset is investigated using a variety of modelling techniques including simple geometric modelling, neural networks and Principal Component Analysis (PCA). Convincing results were obtained for the Declination pointing offset, where applying certain model predictions to observations resulted in an improvement in Declination pointing offset from 5.5 mdeg to 3.2 mdeg (≈50%). The Right Ascension pointing model was considerably less convincing with an improvement of approximately from 5.5 mdeg to 4.5 mdeg (≈20%) in the Right Ascension pointing offset. The Declination pointing offset can be modelled sufficiently well to reduce the pointing offset to less than 4 mdeg, however further investigation of the underlying causes is required for the Right Ascension pointing offset.
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- Date Issued: 2008
That-has-been a discussion on the body cast as that which fixes a subject in time, in relation to notions surrounding the photograph
- Authors: Maree, Christine Fae
- Date: 2008
- Subjects: Barthes, Roland. Camera Lucida Photography, Artistic Photography -- Philosophy Photographic criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2412 , http://hdl.handle.net/10962/d1002208
- Description: Much like a photograph, a casts creates a replica of its referent, thereby immobilising the subject in time. While the subject continues in time and hence ages and inevitably dies the replica does not. With this basic notion of fixing a subject, I have built an argument to contextualise my sculptures, which are made using casts of elderly people. In this discussion I have looked at my works through the ideas of different theorists. The main theorist I have cited is Roland Barthes, specifically with regards to his notion of the photograph as discussed in his book Camera Lucida. I have also referenced three particular artists: Rachel Whiteread, Diane Arbus and Churchill Madikida, as I have found each of their works relate to my work in various ways, creating a different reading from each viewpoint.
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- Date Issued: 2008
The "other" Africans : re-examining representations of sexuality in the work of Nicholas Hlobo and Zanele Muholi
- Authors: Makhubu, Nomusa
- Date: 2008
- Subjects: Hlobo, Nicholas Muholi, Zanele Women in art Photography, Artistic Homosexuality in art Sex in art Performance art Art, African
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2410 , http://hdl.handle.net/10962/d1002206
- Description: Nicholas Hlobo, a sculptor and performance artist, and Zanele Muholi, a photographer and activist, explore different ways of representing sexuality, particularly homosexuality. It is extremely difficult to discuss African sexuality in light of the stain of colonial attitudes that have exoticised and ascribed hypersexuality to African bodies. Moreover, sexuality is often not discussed in the construction of so-called African traditions and this has contributed to rendering African-ness as an exclusive identity. Tensions within and between categories of African-ness are compounded by constituted regulations. For example, Hlobo investigates the obligation of circumcision which seems to contrast the lifestyle and contexts in which he works and resides, and Muholi represents the existence of homosexual and transgender relations, even within conservative categories. The visual imagery of these two artists investigates the boundaries set by different social constructs. These set boundaries have also affected crimes against bisexual, transgender and homosexual individuals, which are reaching an alarming rate. Hlobo questions the validity of structures that marginalise homosexual individuals through drawing attention to the ambivalence of certain statutes. Muholi seeks to publicise the injustices imposed upon homosexual individuals in order to demonstrate the weight of that crisis. Although the South African legal system condones liberated expressions of sexual identity, due to social prejudices homosexual individuals are still treated as if they are not entitled to basic human rights. As a result, hate-crimes are not reported, and when they are they are not taken seriously. Hlobo and Muholi not only bring these issues to light, but also point out the dilemma inscribed in the social and political history of (South) Africa with regards to collective and individual identities. This thesis seeks to provide an analysis of the visual language used by Hlobo and Muholi to subvert the notion that homosexuality is “un-African” and to complicate concepts of gender, sexuality and identity.
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- Date Issued: 2008
The African Peer Review Mechanism : towards Africa's governance audit
- Authors: Molete, Nathan Teboho
- Date: 2008
- Subjects: African Peer Review Mechanism New Partnership for Africa's Development Peer review -- Africa Auditing -- Africa Africa -- Politics and government -- 1960-
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2867 , http://hdl.handle.net/10962/d1007681
- Description: The concept of accountability has grown to become an integral part of a broader political and socio-economic transformation. Closely associated to it is the concept of "auditing" which has established itself as a main driving force of accountability and a core means of delivering it. The extent of the rise and expansion of "auditing" has subsequently come to influence every aspect of modern life and this has led to a situation in which practices have had to adapt to the principles of "auditing" processes. Auditing has become prevalent in both the public and private spheres and this impact has far reaching consequences. The concept of "auditing" is evident in the African Peer Review Mechanism (APRM) and is central to its review process. This thesis focuses on the concept of "auditing" in order to illustrate how the APRM has borrowed and applied insights from other disciplinary practices so as to enhance an understanding of accountability and transparency as features of "good governance" and to explicate how these concepts are conceived within the framework of the New Partnership for Africa's Development (NEPAD). It also clarifies the relationship that exists between "peer review" and "auditing" and argues that rather than being considered as two poles marked by distance from each other "auditing" and "peer review" are closely related and mutually constitutive.
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- Date Issued: 2008
The antecedents of customer satisfaction in a financial institution : a qualitative study
- Authors: Bleske, Adrian
- Date: 2008
- Subjects: Standard Bank Properties , Banks and banking -- South Africa , Banks and banking -- Customer services -- South Africa , Financial services industry -- South Africa , Bank management -- South Africa , Banks and banking -- Customer services -- Effect of marketing on
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:840 , http://hdl.handle.net/10962/d1015482
- Description: The following is a case study report on the Cape Town business unit of Standard Bank Properties. The research project falls within the ambit of services marketing which introduces several unique management challenges for service businesses that sell services as a core offering. The principal aim of the case study is to gain an understanding of why customers bank at the business unit and to discover what aspects are critical to customer satisfaction. A further goal of the research is to examine how the business unit could improve customer satisfaction and to highlight any impediments to further improving customer satisfaction at the business unit. It is generally regarded that quality customer service is essential to building customer relationships and hence the research project emphasis on services marketing and customer satisfaction within a financial services context. The paper commences with an overview of the South African Banking Sector and its unique challenges such as the Financial Service Charter and newly introduced legislation such as Financial Intelligence Centre Act. The case study will specifically investigate the property finance industry and a detailed analysis of the business unit's operations and process flow will also be undertaken. The reason for this background information is to assist the reader to understand how the business unit operates. The research project will investigate four unique differences between goods marketing and services marketing whereafter three theoretical propositions are introduced, namely the dyadic interaction and service encounter, the Service Profit Chain and finally Relationship Marketing. Evidence in the form of a narrative will be led from insights obtained from interviews conducted with customers and staff at the business unit against these propositions with support (or otherwise) from independent surveys and documents from the business unit. The result of this analysis is the identification of several areas of concern specifically: New employees and the service encounter, Problems with FICA, Lack of a customer complaint handling system, Empowerment issues, Turnaround times, Reliance on key staff These insights together with the evidence from the literature review will be analysed and several recommendations made to improve customer service and ultimately customer satisfaction at the business unit. Several recommendations for further research are offered as well as the identification of limitations including but not limited to the specificity of the case study report.
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- Date Issued: 2008
The attitudes of isiXhosa-speaking students toward various languages of learning and teaching (LOLT) issues at Rhodes University
- Authors: Aziakpono, Philomina
- Date: 2008
- Subjects: Rhodes University -- Students -- Attitudes Language and education -- South Africa Xhosa language -- Study and teaching (Higher) -- South Africa English language -- Study and teaching (Higher) -- South Africa Education, Bilingual -- South Africa Language policy -- South Africa Language planning -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2339 , http://hdl.handle.net/10962/d1002621
- Description: This study aims at eliciting opinions and beliefs of isiXhosa-speaking students to revealtheir attitudes toward various languages of learning and teaching (LOLT) issues at RhodesUniversity, and to determine the influence of a number of variables (such as age, gender,schooling background, level of study and field of study) on these attitudes. Another aim of the study is to compare the findings of this research to the recent findings on isiXhosaspeaking students’ language attitudes at the University of the Western Cape (Dyers 1999) and the University of Fort Hare (Dalvit 2004). Qualitative and quantitative methods were used: data was gathered using a survey that employed a questionnaire and interviews (individual and focus group). The questionnaire data is analysed through using percentage scores as well as mean values coupled with Chi-square tests, while the interviews are analysed qualitatively to further confirm the results of the quantitative analysis. Results are also compared with other recent surveys at South African universities. The results reveal that respondents had a generally positive attitude toward English as LOLT, based mainly on instrumental motivations. More importantly, there was a positive attitude toward the use of isiXhosa alongside English. The motivations for the use of isiXhosa were both instrumental and integrative in nature. The majority of respondents who supported a bilingual arrangement did not, however, believe that a fully-fledged bilingual policy would be practical, mainly because of the multilingual nature of Rhodes University. They felt, however, that providing English and isiXhosa exam question-papers, bilingual tutor support and isiXhosa definitions of discipline-specific technical terms would facilitate learning. Most of the variables mentioned above had an influence on the relevant language attitudes, often confirming the findings of other studies. For instance, schooling background greatly influenced the language attitudes of respondents. Those from previously advantaged English-only schools showed very positive attitudes toward an English-only policy, while most respondents from formerly disadvantaged DET bilingual schools were favourably disposed toward a bilingual policy of English and isiXhosa at Rhodes University. A comparison of the findings of this study with those of recent findings on isiXhosa students’ language attitudes at other universities reveals that respondents at the University of Fort Hare were most favourable toward a bilingual policy, those at the University of the Western Cape were to some extent favourable toward a bilingual arrangement, while respondents at Rhodes University were least favourable toward a bilingual policy.
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- Date Issued: 2008
The cryopreservation potential and ultrastructure of Agulhas sole Austroglossus pectoralis spermatozoa
- Authors: Markovina, Michael Zeljan
- Date: 2008
- Subjects: Spermatozoa , Spermatozoa -- Cryopreservation , Aquaculture , Fishes -- Breeding , Soleidae , Flatfishes , Agulhas Current (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5251 , http://hdl.handle.net/10962/d1005094 , Spermatozoa , Spermatozoa -- Cryopreservation , Aquaculture , Fishes -- Breeding , Soleidae , Flatfishes , Agulhas Current (South Africa)
- Description: As the estimated market demand for the Agulhas sole Austroglossus pectoralis exceeds the annual catch from trawlers, this species is a potential aquaculture candidate. Broodstock conditioning and gamete preservation is part of research and development aiming at establishing a breeding protocol for a new aquaculture species. Based on a literature review of the morphology of pleuronectiform spermatozoa, this study was designed firstly, to contribute to the field of spermatozoan morphology by describing the ultrastructure of A. pectoralis spermatozoa. This was followed by an experiment to cryopreserve mature spermatozoa to provide baseline data for future studies on this and related species. The testis of A. pectoralis was a paired structure encased in a membrane, the tunica albuginea. The primary testis was located on the dorsal surface of the rib cage and the secondary testis on the ventral side. The testis was of an unrestricted spermatogonial type, based upon observations of spermatogonia along the entire length of the lobule. Mature spermatozoa of A. pectoralis had an acrosome-free ovoid head 1.68 ± 1.6μm in length and 1.7 ± 1.6μm in diameter, a short mid-piece of 0.5 ± 0.1μm in length, containing 7 irregularly shaped mitochondria forming a ring-like structure at the base of the nucleus. The flagellae were 47.4 ± 4.8μm in length, most with two plasma membrane lateral fin-like projections. However, some flagellae had either zero or three lateral fin projections. Cross-sections of the flagellae showed an axenome with a 9+2 microtubule configuration. The proximal and distal centriols were coaxal, situated deep within the nuclear fossa. The structure of A. pectoralis spermatozoa conformed to the type 1 ect-aquasperm, also found in externally fertilizing species. This type has been suggested to be the plesiomorphic form in Neopterigians. Finally, this study contributed to a cryopreservation protocol for A. pectoralis spermatozoa by testing the two cryoprotectants dimethyl sulphoxide (DMSO) and glycerol. Glycerol, at a concentration of 10%, offered better cryoprotection than DMSO. This was established using flow cytometry analysis of post-thaw nuclear membrane integrity after 64 days of storage in liquid nitrogen. The toxicity of DMSO to isolated cellular proteins may have resulted in DMSO-treated sperm having the highest percent (35.2% ± 3.2%) of non-viable cells compared with 23.0% ± 2.5% and 27.8% ± 3.4% for glycerol and the control, respectively. The presence of sucrose in the Modified Mounib Medium extender solution may explain why 45.5% ± 5% of the sperm cells were potentially viable in the control treatment. Initially, the white margined sole Dagatichthys marginatus (Soleidae) was selected as the most suitable candidate for flatfish aquaculture in South Africa. Thus, the aim of this study was to investigate the cryogenic potential and ultrastructure of D. marginatus spermatozoa. However, due to a skewed sex ratio, there were not enough males available to study this species. A skewed sex ratio is common amongst soleids, thus, the need to develop effective cryopreservation methods and to develop an understanding of sperm morphology so that the best time for cryopreservation can be chosen. In conclusion, this first description of spermatozan morphology of A. pectoralis contributed to our understanding of soleid sperm ultrastructure. In addition, a comparison of testis appearance between fish sampled just prior to spawning season and fish with mature sperm provided information on the spawning season of this species. The findings from the cryopreservation experiment suggested that glycerol was a feasible cryoprotectant for this species when sperm was prepared under field conditions.
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- Date Issued: 2008
The development and evaluation of a cohesion-building programme for a South African male collegiate basketball team
- Authors: Razafimbola, Sandimampita
- Date: 2008
- Subjects: Teamwork (Sports) Basketball teams College sports Sports -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3040 , http://hdl.handle.net/10962/d1002549
- Description: There is a general consensus among sport coaches and practitioners that it is better to work with a cohesive team. Research on cohesion has provided positive links between cohesion and performance as well as the overall well-being of the team and its members. The purpose of this study is to develop and evaluate a cohesion-building programme under an Action Research paradigm. The Group Environment Questionnaire, in parallel with focus group discussions were used to assist in the development and evaluation of a cohesion-building programme tailored to the specific needs of the Rhodes University men’s basketball 1st team. The team is known to be a good team but it was missing something that made it become great. Fostering higher cohesiveness was deemed to be the missing link to the chain of success. Various changes were brought to the 1) team structure, 2) team processes, 3) team environment to enhance the team’s cohesiveness levels. It was found that the programme was positive and powerful in that it accelerated the process of cohesion building within the team. It was also found that the programme had the power to transcend demographical barriers and unite people from diverse backgrounds. Finally, the programme increased the team’s performance level and enabled it to achieve objectives that were never achieved by any other men’s basketball team at Rhodes University before. Naturally there are going to be some ups and downs, especially if you have individuals trying to achieve at a high level. But when we stepped in between the lines, we knew what we were capable of doing. When a pressure situation presented itself, we were plugged into one another like a cohesive unit. That’s why we were able to come back so often and win so many close games. And that’s why we were able to beat more talented team. - Michael Jordan (former Chicago Bulls; NBA Hall of Famer).
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- Date Issued: 2008
The development and evaluation of a custom-built synchronous online learning environment for tertiary education in South Africa
- Authors: Halse, Michelle Louise
- Date: 2008 , 2008-02-23
- Subjects: Education, Higher -- South Africa -- Computer-assisted instruction , Universities and colleges -- Computer networks -- South Africa , Internet in higher education -- South Africa , Distance education -- South Africa -- Computer-assisted instruction , Computer-assisted instruction -- South Africa , Computer science -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4636 , http://hdl.handle.net/10962/d1006545 , Education, Higher -- South Africa -- Computer-assisted instruction , Universities and colleges -- Computer networks -- South Africa , Internet in higher education -- South Africa , Distance education -- South Africa -- Computer-assisted instruction , Computer-assisted instruction -- South Africa , Computer science -- Study and teaching (Higher) -- South Africa
- Description: The Departments of Computer Science and Information Systems at Rhodes University currently share certain honours-level (fourth year) course modules with students from the corresponding departments at the previously disadvantaged University of Fort Hare. These lectures are currently delivered using video-conferencing. This was found to present a number of problems including challenges in terms of implementing desired pedagogical approaches, inequitable learning experiences, student disengagement at the remote venue, and inflexibility of the video-conferencing system. In order to address these problems, various e-learning modes were investigated and synchronous e-learning were found to offer a number of advantages over asynchronous e-learning. Live Virtual Classrooms (LVCs) were identified as synchronous e-learning tools that support the pedagogical principles important to the two universities and to the broader context of South African tertiary education, and commercial LVC applications were investigated and evaluated. Informed by the results of this investigation a small, simple LVC was designed, developed and customised for use in a predominantly academic sphere and deployment in a South African tertiary educational context. Testing and evaluation of this solution was carried out and the results analysed in terms of the LVC’s technical merits and the pedagogical value of the solution as experienced by students and lecturers/facilitators. An evaluation of this solution indicated that the LVC solves a number of the identified problems with video-conferencing and also provides a flexible/customisable/extensible solution that supports highly interactive, collaborative, learner-centred education. The custom LVC solution could be easily adapted to the specific needs of any tertiary educational institute in the country, and results may benefit other tertiary educational institutions involved in or dependant on distance learning.
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- Date Issued: 2008
The development of a putative microbial product for use in crop production
- Authors: Gumede, Halalisani
- Date: 2008
- Subjects: Agricultural productivity , Agriculture -- Economic aspects , Microbial products , Bacterial diseases of plants , Biological pest control agents , Lettuce -- Diseases and pests , Crops -- Nutrition , Bacillus (Bacteria) , Phytopathogenic microorganisms -- Control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3945 , http://hdl.handle.net/10962/d1004004 , Agricultural productivity , Agriculture -- Economic aspects , Microbial products , Bacterial diseases of plants , Biological pest control agents , Lettuce -- Diseases and pests , Crops -- Nutrition , Bacillus (Bacteria) , Phytopathogenic microorganisms -- Control
- Description: The challenges faced by the agricultural sector especially around improving production yields using environmentally friendly solutions have received market attention. Biological intervention can range from application of biological products to enhance the nutritional value of crops or to control plant pathogens. Biostart, a biological product that demonstrated growth enhancement when applied in lettuce crops is currently in the market. The product is comprised of a consortium of bacterial isolates (Bacillus licheniformis, Brevibacillus laterosporus and Bacillus laterosporus) but the contribution of the individual isolates to growth enhancement had not been elucidated. Green house experiments on lettuce seedlings with individual and mixed treatments were commissioned to determine such contribution. There was either no or marginal growth enhancement observed in the experiments. The results showed that the product was effective as a consortium and not as individual isolates. Further isolation and screening for potential Bacilli with antifungal properties was undertaken. An isolate identified as Bacillus subtilis that demonstrated inhibition against a wide spectrum of fungi, and especially the phytopathogenic Verticillium dahliae and Fusarium oxysporum, was successfully identified. The isolate was cryo-preserved and cultivated to significant levels at bench scale. A characterized comparison of different putative products with known systematic fungicide showed potential application even of heat treated products. The product showed control V. dahliae when tested in green houses with potatoes and tomatoes as test crops. This isolate has been targeted for further development as a biological control product.
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- Date Issued: 2008
The devil in disguise a comparative study of Thomas Mann's "Doktor Faustus" (1947) and Klaus Mann's "Mephisto" (1936), focussing on the role of art as an allegory of the rise and fall of Nazi Germany
- Authors: French, Rebecca S C
- Date: 2008
- Subjects: Mann, Thomas, 1875-1955 Doktor Faustus Mann, Klaus, 1906-1949 Mephisto Arts, German -- 20th Century Art, Germany -- 20th Century National socialism in art National socialism in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3582 , http://hdl.handle.net/10962/d1002157
- Description: This thesis compares the novels Doktor Faustus: das Leben des deutschen Tonsetzers Adrian Leverkühn, erzählt von einem Freunde (Thomas Mann) and Mephisto: Roman einer Karriere (Klaus Mann), insofar as they are portrayals of the situation in Germany during the Third Reich. Essentially a comparative study, I explore similarities and differences – thematic and conceptual – by situating both novels in their socio-historical moment (Chapter 1), exploring their conceptions of German national identity (Chapter 2), tracing intertextual connections to other works (Chapter 3), and, finally, examining their understanding of and reliance on art as insofar as it provides the allegorical framework for their respective portrayals of Nazi Germany (Chapter 4).
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- Date Issued: 2008
The difficulty of living well: effort and failure in the good life
- Authors: Moore, Jesse Alexander
- Date: 2008
- Subjects: Conduct of life Ethics Happiness Values Failure (Psychology) Success Struggle
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2715 , http://hdl.handle.net/10962/d1002845
- Description: We all want to live good lives, but due to the difficulty involved, few of us ever succeed. We usually either fail in our attempts to live well or remain with our safer, and less worthwhile, options. In spite of this, there has been little, if any, investigation of the role that difficulty plays in our attempts to live well, and thus in our conceptions of the good life. Within the field of the good life, philosophers tend to acknowledge the fact that good lives are difficult to live, and leave it at that. Since we must all face the difficulty of living well, the lack of analysis of the implications of difficulty seems a glaring oversight. In order to redress this, I explore the role that difficulty plays in two requirements for living well, namely achievement and reflection. Firstly, I examine the relationship between effort and achievement. I argue that difficulty just is the requirement of effort, and that it is required in order for our achievements to be meaningful and for us to value them. Secondly, I look at the relationship between failure and reflection. I argue that reflection on our failures can lead us to knowledge that helps us to live well and that we would not usually come to if we did not fail. Finally, I look at the roles of effort and failure in some accounts of the good life and I draw on psychological research and theory to provide support for my conclusions about the positive effects of effort. I conclude by examining the implications of reducing difficulty for the future of humankind.
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- Date Issued: 2008
The distinction between tax evasion, tax avoidance and tax planning
- Authors: Tarrant, Greg
- Date: 2008
- Subjects: South African Revenue Service , Tax evasion -- South Africa , Tax planning -- South Africa , Income tax -- South Africa , Income tax -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:897 , http://hdl.handle.net/10962/d1004549
- Description: Tax avoidance has been the subject of intense scrutiny lately by both the South African Revenue Service ("the SARS") and the media. This attention stems largely from the recent withdrawal of section 103(1) together with the introduction of section 80A to 80L of the South African Income Tax Act. However, this attention is not limited to South Africa. Revenue authorities worldwide have focused on the task of challenging tax avoidance. The approach of the SARS to tackling tax avoidance has been multi-faceted. In the Discussion Paper on Tax Avoidance and Section 103 (1) of the South African Income Tax Act they begin with a review of the distinction between tax evasion, tax avoidance and tax planning. Following a call for comment the SARS issued an Interim Response followed by the Revised Proposals which culminated in the withdrawal of the longstanding general anti-avoidance rules housed in section 103(1) and the introduction of new and more comprehensive anti-avoidance rules. In addition, the SARS has adopted an ongoing media campaign stressing the importance of paying tax in a country with a large development agenda like that of South Africa, the need for taxpayers to adopt a responsible attitude to the management of tax and the inclusion of responsible tax management as the greatest measure of a taxpayer's corporate and social investment. In tandem with this message the SARS have sought to vilify those taxpayers who engage in tax avoidance. The message is clear: tax avoidance carries reputational risks; those who engage in tax avoidance are unpatriotic or immoral and their actions simply result in an unfair shifting of the tax burden. The SARS is not alone in the above approach. Around the world tax authorities have been echoing the same message. The message appears to be working. Accounting firms speak of a "creeping conservatism" that has pervaded company boardrooms. What is not clear, however, is whether taxpayers, in becoming more conservative, are simply more fully aware of tax risks and are making informed decisions or whether they are simply responding to external events, such as the worldwide focus by revenue authorities and the media on tax avoidance. Whatever the reason, it is now critical, particularly in the case of corporate taxpayers, that their policies for tax and its attendant risks need to be as sophisticated, coherent and transparent as its policies in all other areas involving multiple stakeholders, such as suppliers, customers, staff and investors. How does a company begin to set its tax philosophy and strategic direction or to determine its appetite for risk? A starting point, it is submitted would be a review of the distinction between tax evasion, avoidance and planning with a heightened sensitivity to the unfamiliar ethical, moral and social risks. The goal of this thesis was to clearly define the distinction between tax evasion, tax avoidance and tax planning from a legal interpretive, ethical and historical perspective in order to develop a rudimentary framework for the responsible management of strategic tax decisions, in the light of the new South African general anti-avoidance legislation. The research methodology entails a qualitative research orientation consisting of a critical conceptual analysis of tax evasion and tax avoidance, with a view to establishing a basic framework to be used by taxpayers to make informed decisions on tax matters. The analysis of the distinction in this work culminated in a diagrammatic representation of the distinction between tax evasion, tax avoidance and tax planning emphasising the different types of tax avoidance from least aggressive to the most abusive and from the least objectionable to most objectionable. It is anticipated that a visual representation of the distinction, however flawed, would result in a far more pragmatic tool to taxpayers than a lengthy document. From a glance taxpayers can determine the following: That tax avoidance is legal; that different forms of tax avoidance exist, some forms being more aggressive than others; that aggressive forms of tax avoidance carry reputational risks; and that in certain circumstances aggressive tax avoidance schemes may border on tax evasion. This, it is envisaged, may prompt taxpayers to ask the right questions when faced with an external or in-house tax avoidance arrangement rather than simply blindly accepting or rejecting the arrangement.
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- Date Issued: 2008
The ecology and conservation of Mackinder's eagle owls (Bubo capensis mackinderi) in central Kenya in relation to agricultural land-use and cultural attitudes
- Authors: Ogada, Darcy L
- Date: 2008
- Subjects: Cape eagle owl -- Kenya Cape eagle owl -- Habitat -- Kenya Cape eagle owl -- Breeding -- Kenya Cape eagle owl -- Nutrition -- Kenya Bubo -- Kenya Wildlife conservation -- Kenya Biodiversity conservation -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5668 , http://hdl.handle.net/10962/d1005353
- Description: The loss of habitat to agriculture is a worldwide problem for biodiversity conservation. One species that has seemingly been able to adapt to the conversion of forests to farmlands is Mackinder’s eagle owl (Bubo capensis mackinderi), which inhabits highland areas, but little is known of its ecology, especially outside of protected areas. This study examined the impact of agricultural practices and farmer’s attitudes on the foraging and population ecology of the Mackinder’s eagle owl in central Kenya. Owl territories were monitored monthly from June 2004- October 2006 for signs of occupancy, breeding activity, mortality and to collect data on food resources. Nest site characteristics were measured for all known nests. Because previous studies showed an affinity for rodents, small mammals were trapped monthly using mark-recapture methodology. In each territory, the type and amount of farm crops were measured each month and farmers were interviewed about their knowledge and beliefs about owls. Mackinder’s eagle owls in central Kenya lived at extremely high density 0.87 owl pairs/km². This density was high compared to other populations of Mackinder’s eagle owl and to Eurasian eagle owl (Bubo bubo) populations in Europe. Breeding success was 48% over three years and this compared well with other species of eagle owl inhabiting human-disturbed areas. All nests and roosts were located in river valleys, and all successful nest sites were located on cliffs or other inaccessible rocky terrain. Nest sites were located adjacent to farms, which provided for both open hunting and an abundance of prey. Breeding activity was concentrated after the rainy seasons and this was likely linked to prey availability after the rains. Agricultural activities generally had a positive effect on rodent populations. Small mammal trapping results revealed that rodents were over 14 times more abundant in farms than in adjacent grassland habitat. This population of Mackinder’s eagle owl had a very catholic diet and consumed mostly mammalian prey species including hares, giant rats, root rats, grooved-tooth rats and small rodents. Small rodents accounted for almost half of the owls’ diet and when their numbers increased, owls responded by consuming more of them, indicating the importance of farming activities to this population of owls. Other populations of eagle owl inhabiting human-disturbed areas had diet widths positively related to levels of habitat disturbance. This result supported optimal foraging theory that more productive environments have predators with more specialized diets, while patchy environments have generalist predators. The ecology of this population of Mackinder’s eagle owls was heavily influenced by human agricultural activities, which generally had a positive effect on their population. Farming activities changed rapidly both within and between seasons as plots were small and neighbouring farmers planted various crops at different times of the year and this was enhanced by irrigation in some areas. Year-round availability of forage within farms had a positive effect on owl prey species, some of which increased relative to the type and amount of crops found in farms. However, 57% of owl injuries and mortalities that occurred were related either directly or indirectly to human activities. Cultural prejudices against owls remain the biggest threat to this population’s long-term persistence. Farmer education was shown to play a significant role in overcoming negative beliefs about owls. Because Mackinder’s eagle owls are highly adaptable to anthropomorphic landscape changes, largely due to their adaptability as food generalists, they are one of the few top predators remaining in this highly disturbed agricultural system. However, populations within agricultural areas remain especially vulnerable to negative human attitudes towards owls due to their close association with human activities.
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- Date Issued: 2008
The effect of restricted environments on selected postural, physiological and perceptual responses
- Authors: Wolfe, Amy
- Date: 2008
- Subjects: Human engineering , Posture , Human mechanics , Work environment , Human beings -- Effect of environment on , Musculoskeletal system -- Wounds and injuries , Industrial safety , Work -- Physiological aspects , Stress (Physiology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5115 , http://hdl.handle.net/10962/d1005193 , Human engineering , Posture , Human mechanics , Work environment , Human beings -- Effect of environment on , Musculoskeletal system -- Wounds and injuries , Industrial safety , Work -- Physiological aspects , Stress (Physiology)
- Description: Manual lifting tasks are the predominant means of transporting materials in industry with many of these tasks being performed in confined spaces. Research has tended to focus on the biomechanical implications of working in small spaces with a decided lack of information about the physiological and perceptual responses in these environments. This holistic study therefore investigated the manner in which the human operator responded to conditions where the ceiling height was lowered and reach demands increased. Thirty-two young physically active male subjects (age: 21.55yr; stature: 1810mm) were recruited to complete a 2-way repeated measures experiment during which four lifting protocols where different combinations of ceiling height (‘normal’ or reduced to 1460mm in height) and reach demands (400mm or 800mm) were tested. A crude postural analysis was conducted while physiological responses were detailed and continuously monitored. Perceptual responses were also assessed. The tasks with a ‘normal’ ceiling height (mean compression forces: 2615N; mean shearing forces: 388N) and the greatest reach distance (mean compression forces: 3655N; mean shearing forces: 386N) placed individuals under the highest strain. Mean heart rate (HR) responses were significantly lower (p < 0.05) in the URN condition when compared to the RF condition. Furthermore, HR responses were statistically significantly affected by the height of the ceiling and the reach depth. Statistically significant differences (p< 0.05) in mean tidal volume (VT) occurred in the least (URN) and most (RF) restrictive conditions. Statistically significant differences (p < 0.05) in mean VE were evident between URN and URF, between URN and RF and between RN and RF. Ceiling height and reach demands had a statistically significant effect on all respiratory responses. There was a statistically significant difference in mean oxygen consumption (VO2) between the URN and all other conditions, and between the most restricted task (RF) and all other conditions. Both the effect of ceiling height and reach demands had a statistically statistically significant impact on VO2. Respiratory quotient (RQ) was significantly higher when loads were moved over 800mm compared to 400mm yet ceiling height did not have a statistically significant effect on RQ. Mean energy expenditure was significantly higher in the RF condition compared to the two least restrictive conditions (URN and RN). Statistically significant differences in EE were also evident between URN and RN, and between URN and URF. EE was significantly affected by reductions in ceiling height and increases in reach demands. Perceptually, the RF task (mean ‘Central’ RPE of 11) was perceived to place significantly greater cardiorespiratory demands on the operator compared to the URN (CRPE: 10) and RN (CRPE: 10) conditions. Statistically significant differences in perceived musculoskeletal strain only occurred between URN and RF. The effect of reach was perceived to have a statistically significant effect on both cardiovascular and musculoskeletal demands whereas ceiling height only had a statistically significant effect on musculoskeletal demands. The greatest discomfort was experienced in the lower back with the most intense discomfort occurring in the RN condition.
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- Date Issued: 2008