Mechanisms generating biological diversity in the genus Platypleura Amyot & Serville, 1843 (Hemiptera: Cicadidae) in southern Africa: implications of a preliminary molecular phylogeny
- Villet, Martin H, Barker, Nigel P, Lunt, N
- Authors: Villet, Martin H , Barker, Nigel P , Lunt, N
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6554 , http://hdl.handle.net/10962/d1006012
- Description: Truly understanding biological diversity requires a move from descriptive studies to mechanistic interpretations based on comparative biology and a thorough recognition of the natural history of the focal organisms. A useful step in such comparative studies is the generation of a phylogeny, so that one can assess the phylogenetic independence of the focal taxa and trace the evolutionary significance of their characteristics. As a preliminary to such studies on the platypleurine cicada genus Platypleura, we sequenced 498 bases of the cytochrome oxidase I (COI) gene from thirteen African species. To circumvent problems with outgroup selection, we also included sequences from representatives of the platypleurine genera Brevisiana, Capcicada, Munza, Oxypleura, Severiana, and Systophlochius, all of the subtribe Platypleuriti, and two species of the genus Ugada, of the subtribe Hainanosemiiti. The resulting phylogenies support the synonymization of the monotypic genus Systophlochius with the widespread, speciose genus Platypleura; confirm the placement of Platypleura sp. 7 in that genus; and confirm the independence of Capcicada and Platypleura. Although the preliminary phylogeny lacks strong support at many nodes, it suggests that three radiations of Platypleura have occurred in southern Africa and that there was progressive southward speciation of these radiations. A novel modification of the ancestral area analysis further suggests that the group has an ancestral association with acacias but there were five independent speciation events associated with host- switching. These insights can be summarized by a general hypothesis that the mechanisms underlying platypleurine biodiversity in southern Africa involve two ancient vicariance events and subsequent speciation by vicariance, switching of plant associations, and changes of habitat preferences. We offer this example to illustrate how analysis of preliminary data can help to generate hypotheticodeductive research hypotheses, to provoke interest in testing these hypotheses, and to illustrate the utility of phylogenies beyond systematics.
- Full Text:
- Date Issued: 2004
- Authors: Villet, Martin H , Barker, Nigel P , Lunt, N
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6554 , http://hdl.handle.net/10962/d1006012
- Description: Truly understanding biological diversity requires a move from descriptive studies to mechanistic interpretations based on comparative biology and a thorough recognition of the natural history of the focal organisms. A useful step in such comparative studies is the generation of a phylogeny, so that one can assess the phylogenetic independence of the focal taxa and trace the evolutionary significance of their characteristics. As a preliminary to such studies on the platypleurine cicada genus Platypleura, we sequenced 498 bases of the cytochrome oxidase I (COI) gene from thirteen African species. To circumvent problems with outgroup selection, we also included sequences from representatives of the platypleurine genera Brevisiana, Capcicada, Munza, Oxypleura, Severiana, and Systophlochius, all of the subtribe Platypleuriti, and two species of the genus Ugada, of the subtribe Hainanosemiiti. The resulting phylogenies support the synonymization of the monotypic genus Systophlochius with the widespread, speciose genus Platypleura; confirm the placement of Platypleura sp. 7 in that genus; and confirm the independence of Capcicada and Platypleura. Although the preliminary phylogeny lacks strong support at many nodes, it suggests that three radiations of Platypleura have occurred in southern Africa and that there was progressive southward speciation of these radiations. A novel modification of the ancestral area analysis further suggests that the group has an ancestral association with acacias but there were five independent speciation events associated with host- switching. These insights can be summarized by a general hypothesis that the mechanisms underlying platypleurine biodiversity in southern Africa involve two ancient vicariance events and subsequent speciation by vicariance, switching of plant associations, and changes of habitat preferences. We offer this example to illustrate how analysis of preliminary data can help to generate hypotheticodeductive research hypotheses, to provoke interest in testing these hypotheses, and to illustrate the utility of phylogenies beyond systematics.
- Full Text:
- Date Issued: 2004
Metus in the Roman law of obligations
- Authors: Glover, Graham B
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6336 , http://hdl.handle.net/10962/d1012401
- Description: [From the introduction]: An entire title of book four of Justinian’s Digest is devoted to explaining the doctrine of metus as it was understood at the time of the codification of the Roman law. That title begins with the following statement: "The praetor says: 'I will not hold valid what has been done under duress.'" This unequivocal statement of legal principle illustrates, in very general terms, that by the time the Corpus Iuris Civilis was compiled, the Romans disapproved of persons using threats to inspire the creation of legal obligations, and that it was possible to avoid the legal consequences of an obligation because it was induced by metus. The Corpus Iuris Civilis remains our most valuable source of authority with regard to how duress cases were treated in Roman times. But the relevant textual sources pose some fundamental difficulties. Far from containing a coherent, structured analysis of the law, the relevant passages in fact amount to a jigsaw-puzzle of uncoordinated, haphazard, and occasionally contradictory legal propositions
- Full Text:
- Date Issued: 2004
- Authors: Glover, Graham B
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6336 , http://hdl.handle.net/10962/d1012401
- Description: [From the introduction]: An entire title of book four of Justinian’s Digest is devoted to explaining the doctrine of metus as it was understood at the time of the codification of the Roman law. That title begins with the following statement: "The praetor says: 'I will not hold valid what has been done under duress.'" This unequivocal statement of legal principle illustrates, in very general terms, that by the time the Corpus Iuris Civilis was compiled, the Romans disapproved of persons using threats to inspire the creation of legal obligations, and that it was possible to avoid the legal consequences of an obligation because it was induced by metus. The Corpus Iuris Civilis remains our most valuable source of authority with regard to how duress cases were treated in Roman times. But the relevant textual sources pose some fundamental difficulties. Far from containing a coherent, structured analysis of the law, the relevant passages in fact amount to a jigsaw-puzzle of uncoordinated, haphazard, and occasionally contradictory legal propositions
- Full Text:
- Date Issued: 2004
Miscarriage : an exploration of women's experience : a qualitative study
- Watson, Julia Margretha Garland
- Authors: Watson, Julia Margretha Garland
- Date: 2004
- Subjects: Miscarriage -- Psychological aspects , Loss (Psychology) , Bereavement -- Psychological aspects , Infants -- Death -- Psychological aspects , Fetal death -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:688 , http://hdl.handle.net/10962/d1003735 , Miscarriage -- Psychological aspects , Loss (Psychology) , Bereavement -- Psychological aspects , Infants -- Death -- Psychological aspects , Fetal death -- Psychological aspects
- Description: Miscarriage can result in significant psychological distress to women. However, many women experience a cultural norm which attributes minimal meaning to the loss. This is reflected in the lack of support experienced from interaction with both medical professionals and those within the individual's social context. This qualitative study reports on the unique experiences of six South African women; their experience of other's reactions to their miscarriage; and their recommendations for better coping with the experience. Data was gathered using one semi-structured interview. Data reduction and analysis followed using a four-stage model of thematic outlines, coding, and comparisons (Marshall and Rossman 1998:152; Marck and Field 1994:9). The objective of the analysis sought to compare the themes generated by the actual data collected with those described in other studies. In this way the findings of the study are generalisable to a larger population and allows for a greater sense of representivity (Silverman 1994:160). Comparisons were made between the women's experiences, as told by them, and Bowles' identification of the Four Domains of Miscarriage Distress Symptoms (2000). The women viewed psychological support as essential in the process of coping; and acknowledgement of their loss as being the loss of a child, as a strong determinant of coming to terms with the loss. A strong need to have support from other women who had shared the experience was voiced. Recommendations for improved intervention are made. In short the core recommendations are: the provision of patient follow-up; the provision of written material; and, specialist training for those working in the area of pregnancy loss.
- Full Text:
- Date Issued: 2004
- Authors: Watson, Julia Margretha Garland
- Date: 2004
- Subjects: Miscarriage -- Psychological aspects , Loss (Psychology) , Bereavement -- Psychological aspects , Infants -- Death -- Psychological aspects , Fetal death -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:688 , http://hdl.handle.net/10962/d1003735 , Miscarriage -- Psychological aspects , Loss (Psychology) , Bereavement -- Psychological aspects , Infants -- Death -- Psychological aspects , Fetal death -- Psychological aspects
- Description: Miscarriage can result in significant psychological distress to women. However, many women experience a cultural norm which attributes minimal meaning to the loss. This is reflected in the lack of support experienced from interaction with both medical professionals and those within the individual's social context. This qualitative study reports on the unique experiences of six South African women; their experience of other's reactions to their miscarriage; and their recommendations for better coping with the experience. Data was gathered using one semi-structured interview. Data reduction and analysis followed using a four-stage model of thematic outlines, coding, and comparisons (Marshall and Rossman 1998:152; Marck and Field 1994:9). The objective of the analysis sought to compare the themes generated by the actual data collected with those described in other studies. In this way the findings of the study are generalisable to a larger population and allows for a greater sense of representivity (Silverman 1994:160). Comparisons were made between the women's experiences, as told by them, and Bowles' identification of the Four Domains of Miscarriage Distress Symptoms (2000). The women viewed psychological support as essential in the process of coping; and acknowledgement of their loss as being the loss of a child, as a strong determinant of coming to terms with the loss. A strong need to have support from other women who had shared the experience was voiced. Recommendations for improved intervention are made. In short the core recommendations are: the provision of patient follow-up; the provision of written material; and, specialist training for those working in the area of pregnancy loss.
- Full Text:
- Date Issued: 2004
Modelling and rendering techniques for african hairstyles
- Patrick, Deborah, Bangay, Shaun D, Lobb, Adele
- Authors: Patrick, Deborah , Bangay, Shaun D , Lobb, Adele
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432905 , vital:72911 , https://doi.org/10.1145/1029949.1029971
- Description: We develop or enhance hair modelling and rendering techniques to produce three different forms of hair commonly found in African hairstyles. The forms of hair are natural curly hair, straightened hair, and braids or twists of hair. We use an implicit model, implemented as a series of textured layers to represent curly hair. Straightened hair is represented explicitly, and mod-elled by defining and replicating a few control hairs. Braids and twists are implemented as textured generalized cylinders. A synthesis of existing hair illumination models is used as a basis for an African hair illumination model. Parameter values to match African hair characteristics are discussed. A number of complete African hairstyles are shown, demonstrating that the techniques can be used to model and render African hair successfully.
- Full Text:
- Date Issued: 2004
- Authors: Patrick, Deborah , Bangay, Shaun D , Lobb, Adele
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432905 , vital:72911 , https://doi.org/10.1145/1029949.1029971
- Description: We develop or enhance hair modelling and rendering techniques to produce three different forms of hair commonly found in African hairstyles. The forms of hair are natural curly hair, straightened hair, and braids or twists of hair. We use an implicit model, implemented as a series of textured layers to represent curly hair. Straightened hair is represented explicitly, and mod-elled by defining and replicating a few control hairs. Braids and twists are implemented as textured generalized cylinders. A synthesis of existing hair illumination models is used as a basis for an African hair illumination model. Parameter values to match African hair characteristics are discussed. A number of complete African hairstyles are shown, demonstrating that the techniques can be used to model and render African hair successfully.
- Full Text:
- Date Issued: 2004
Models of Internet Connectivity in Previously Disadvantaged Secondary Schools in the Eastern Cape
- Brandt, Ingrid, Terzoli, Alfredo, Hodgkinson-Williams, Cheryl
- Authors: Brandt, Ingrid , Terzoli, Alfredo , Hodgkinson-Williams, Cheryl
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427602 , vital:72450 , https://d1wqtxts1xzle7.cloudfront.net/43383861/Models_of_Internet_Connectivity_in_Previ20160305-2534-1salhbh-libre.pdf?1457175561=andresponse-content-disposi-tion=inline%3B+filename%3DModels_of_Internet_Connectivity_in_Previ.pdfandExpires=1714994733andSignature=AS-VDG85ZQPZzWwvz3ITck4K9JIs4zA2bCzFW9LLCYPj9aI~gA4qSOmURIkQz4VE2ZiOrjWHDyeebZyoYs50SPW8~IF31aXPoz8MFAY~qz0DgIAVCNF5k7vXqnCxmnuE5zMEjnxxkNigthvwSD4yDrpJ0Hy5VdN20~3p1j0E9N7zaiTPexGvrH85p3k~bb4Mht00QdltgVGO3tcqiAA9-eskZ--mS7X1acD3ehhXVG7hGVxLqq6TsjdEWOKh6Z4Gkt0Utdcx84zWAkC56yN8GoHwTbxt1DkjMOuatLhWppfMLNQPy6hNYga9GNq-0dalbisbJ1G-Nrbez0O0w2w8EA__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Computers are increasingly considered a valuable tool in Education, not only for the purpose of administration but also for teaching and learning. This project aims to model Internet connectivity to previously disadvan-taged schools in the Eastern Cape by investigating known networking technologies in the context of such schools. We look at wired and wireless technologies, while bearing in mind issues such as cost, organisation ca-pacity and such like.
- Full Text:
- Date Issued: 2004
- Authors: Brandt, Ingrid , Terzoli, Alfredo , Hodgkinson-Williams, Cheryl
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/427602 , vital:72450 , https://d1wqtxts1xzle7.cloudfront.net/43383861/Models_of_Internet_Connectivity_in_Previ20160305-2534-1salhbh-libre.pdf?1457175561=andresponse-content-disposi-tion=inline%3B+filename%3DModels_of_Internet_Connectivity_in_Previ.pdfandExpires=1714994733andSignature=AS-VDG85ZQPZzWwvz3ITck4K9JIs4zA2bCzFW9LLCYPj9aI~gA4qSOmURIkQz4VE2ZiOrjWHDyeebZyoYs50SPW8~IF31aXPoz8MFAY~qz0DgIAVCNF5k7vXqnCxmnuE5zMEjnxxkNigthvwSD4yDrpJ0Hy5VdN20~3p1j0E9N7zaiTPexGvrH85p3k~bb4Mht00QdltgVGO3tcqiAA9-eskZ--mS7X1acD3ehhXVG7hGVxLqq6TsjdEWOKh6Z4Gkt0Utdcx84zWAkC56yN8GoHwTbxt1DkjMOuatLhWppfMLNQPy6hNYga9GNq-0dalbisbJ1G-Nrbez0O0w2w8EA__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: Computers are increasingly considered a valuable tool in Education, not only for the purpose of administration but also for teaching and learning. This project aims to model Internet connectivity to previously disadvan-taged schools in the Eastern Cape by investigating known networking technologies in the context of such schools. We look at wired and wireless technologies, while bearing in mind issues such as cost, organisation ca-pacity and such like.
- Full Text:
- Date Issued: 2004
Molecular chaperones in biology, medicine and protein biotechnology
- Boshoff, Aileen, Nicoll, William S, Hennessy, Fritha, Ludewig, M H, Daniel, Sheril, Modisakeng, Keoagile W, Shonhai, Addmore, McNamara, Caryn, Bradley, Graeme, Blatch, Gregory L
- Authors: Boshoff, Aileen , Nicoll, William S , Hennessy, Fritha , Ludewig, M H , Daniel, Sheril , Modisakeng, Keoagile W , Shonhai, Addmore , McNamara, Caryn , Bradley, Graeme , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6457 , http://hdl.handle.net/10962/d1004479
- Description: Molecular chaperones consist of several highly conserved families of proteins, many of which consist of heat shock proteins. The primary function of molecular chaperones is to facilitate the folding or refolding of proteins, and therefore they play an important role in diverse cellular processes including protein synthesis, protein translocation, and the refolding or degradation of proteins after cell stress. Cells are often exposed to different stressors, resulting in protein misfolding and aggregation. It is now well established that the levels of certain molecular chaperones are elevated during stress to provide protection to the cell. The focus of this review is on the impact of molecular chaperones in biology, medicine and protein biotechnology, and thus covers both fundamental and applied aspects of chaperone biology. Attention is paid to the functions and applications of molecular chaperones from bacterial and eukaryotic cells, focusing on the heat shock proteins 90 (Hsp90), 70 (Hsp70) and 40 (Hsp40) classes of chaperones, respectively. The role of these classes of chaperones in human diseases is discussed, as well as the parts played by chaperones produced by the causative agents of malaria and trypanosomiasis. Recent advances have seen the application of chaperones in improving the yields of a particular target protein in recombinant protein production. The prospects for the targeted use of molecular chaperones for the over-production of recombinant proteins is critically reviewed, and current research on these chaperones at Rhodes University is also discussed.
- Full Text:
- Date Issued: 2004
- Authors: Boshoff, Aileen , Nicoll, William S , Hennessy, Fritha , Ludewig, M H , Daniel, Sheril , Modisakeng, Keoagile W , Shonhai, Addmore , McNamara, Caryn , Bradley, Graeme , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6457 , http://hdl.handle.net/10962/d1004479
- Description: Molecular chaperones consist of several highly conserved families of proteins, many of which consist of heat shock proteins. The primary function of molecular chaperones is to facilitate the folding or refolding of proteins, and therefore they play an important role in diverse cellular processes including protein synthesis, protein translocation, and the refolding or degradation of proteins after cell stress. Cells are often exposed to different stressors, resulting in protein misfolding and aggregation. It is now well established that the levels of certain molecular chaperones are elevated during stress to provide protection to the cell. The focus of this review is on the impact of molecular chaperones in biology, medicine and protein biotechnology, and thus covers both fundamental and applied aspects of chaperone biology. Attention is paid to the functions and applications of molecular chaperones from bacterial and eukaryotic cells, focusing on the heat shock proteins 90 (Hsp90), 70 (Hsp70) and 40 (Hsp40) classes of chaperones, respectively. The role of these classes of chaperones in human diseases is discussed, as well as the parts played by chaperones produced by the causative agents of malaria and trypanosomiasis. Recent advances have seen the application of chaperones in improving the yields of a particular target protein in recombinant protein production. The prospects for the targeted use of molecular chaperones for the over-production of recombinant proteins is critically reviewed, and current research on these chaperones at Rhodes University is also discussed.
- Full Text:
- Date Issued: 2004
Moral reform and the desiderata of responses to wrongdoing: the production of a "morally autonomous person freely attached to the good"
- Authors: Waller, Heath Frederick
- Date: 2004 , 2013-06-14
- Subjects: Victims of crimes -- Attitudes , Criminals -- Rehabilitation , Punishment -- Psychological aspects , Social ethics , Punishment
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2730 , http://hdl.handle.net/10962/d1003805 , Victims of crimes -- Attitudes , Criminals -- Rehabilitation , Punishment -- Psychological aspects , Social ethics , Punishment
- Description: Moral reform is a neglected response to wrongdoing that has been incorrectly portrayed as a practice involving illegitimate treatment of wrongdoers and as totally unsatisfying to those theorists advocating backward-looking practices such as retributive punishment. A clear explanation of the ethical legitimacy and practical necessity of the reformative techniques moral reform involves has been missed, and this paper details the design of moral reform proper in order to fill this gap in punishment theory. The moral reform of an offender is identified as a desideratum of responses to wrongdoing and it is explained what moral reform ought to entail. The claim that moral reform qualifies as the overriding aim of responses to wrongdoing is argued for on the grounds that this practice is capable of achieving all the established ends of responses to wrongdoing. The legitimate desiderata of our practices are identified as those usually selected as the ends of punishment practices, and moral reform must accomplish these if it is to be accepted. Moral reform is shown to realise the goals of punishments as the fortunate effects of what is done to achieve an offender's moral improvement and of what reformees do in taking responsibility for their actions. The suffering involved in moral reform receives particular emphasis since the practice will never satisfy unless it accommodates the widely-held intuition that the offender must suffer sufficiently as a consequence of his wrongdoing. Moral reform is further portrayed as the most meaningful practice for its ability to satisfy the appropriate needs and desires victims have in response to their victimization. A central claim of the thesis is that moral reform best serves the victim, since it most effectively relieves the victim's emotional responses to wrongdoing and is as adept as punishment at the expression of these same emotions. Reformers advocate a constructive response to wrongdoing that benefits all affected parties. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2004
- Authors: Waller, Heath Frederick
- Date: 2004 , 2013-06-14
- Subjects: Victims of crimes -- Attitudes , Criminals -- Rehabilitation , Punishment -- Psychological aspects , Social ethics , Punishment
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2730 , http://hdl.handle.net/10962/d1003805 , Victims of crimes -- Attitudes , Criminals -- Rehabilitation , Punishment -- Psychological aspects , Social ethics , Punishment
- Description: Moral reform is a neglected response to wrongdoing that has been incorrectly portrayed as a practice involving illegitimate treatment of wrongdoers and as totally unsatisfying to those theorists advocating backward-looking practices such as retributive punishment. A clear explanation of the ethical legitimacy and practical necessity of the reformative techniques moral reform involves has been missed, and this paper details the design of moral reform proper in order to fill this gap in punishment theory. The moral reform of an offender is identified as a desideratum of responses to wrongdoing and it is explained what moral reform ought to entail. The claim that moral reform qualifies as the overriding aim of responses to wrongdoing is argued for on the grounds that this practice is capable of achieving all the established ends of responses to wrongdoing. The legitimate desiderata of our practices are identified as those usually selected as the ends of punishment practices, and moral reform must accomplish these if it is to be accepted. Moral reform is shown to realise the goals of punishments as the fortunate effects of what is done to achieve an offender's moral improvement and of what reformees do in taking responsibility for their actions. The suffering involved in moral reform receives particular emphasis since the practice will never satisfy unless it accommodates the widely-held intuition that the offender must suffer sufficiently as a consequence of his wrongdoing. Moral reform is further portrayed as the most meaningful practice for its ability to satisfy the appropriate needs and desires victims have in response to their victimization. A central claim of the thesis is that moral reform best serves the victim, since it most effectively relieves the victim's emotional responses to wrongdoing and is as adept as punishment at the expression of these same emotions. Reformers advocate a constructive response to wrongdoing that benefits all affected parties. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2004
Multiprotocol control of networked home entertainment devices
- Authors: Siebörger, David Robert
- Date: 2004
- Subjects: Home entertainment systems , Home video systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4642 , http://hdl.handle.net/10962/d1006585 , Home entertainment systems , Home video systems
- Description: Networks will soon connect a wide range of computing devices within the home. Amongst those devices will be home entertainment devices. Remote control over the network will be a key application for networked entertainment devices, and requires a protocol for communication understood by both controller and controlled device. Devices capable of communication using multiple control protocols will be compatible with a wider range of controllers than those which implement only one control protocol. This work examines home networks and a number of control protocols. The implementations of the UPnP and AV/C protocols for an AV receiver are described. The issues involved in the concurrent use of multiple control protocols to control a device are considered, possible methods of concurrent control discussed, and a solution which simulates virtual copies of the device is implemented and tested.
- Full Text:
- Date Issued: 2004
- Authors: Siebörger, David Robert
- Date: 2004
- Subjects: Home entertainment systems , Home video systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4642 , http://hdl.handle.net/10962/d1006585 , Home entertainment systems , Home video systems
- Description: Networks will soon connect a wide range of computing devices within the home. Amongst those devices will be home entertainment devices. Remote control over the network will be a key application for networked entertainment devices, and requires a protocol for communication understood by both controller and controlled device. Devices capable of communication using multiple control protocols will be compatible with a wider range of controllers than those which implement only one control protocol. This work examines home networks and a number of control protocols. The implementations of the UPnP and AV/C protocols for an AV receiver are described. The issues involved in the concurrent use of multiple control protocols to control a device are considered, possible methods of concurrent control discussed, and a solution which simulates virtual copies of the device is implemented and tested.
- Full Text:
- Date Issued: 2004
Music and (post)colonialism : the dialectics of choral culture on a South African frontier
- Authors: Olwage, Grant
- Date: 2004
- Subjects: Choral music -- South Africa -- History Black people -- South Africa -- Music -- History and criticism Bokwe, John Knox, 1855-1922
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2679 , http://hdl.handle.net/10962/d1007717
- Description: This thesis explores the genesis of black choralism in late-nineteenth-century colonial South Africa, attending specifically to its dialectic with metropolitan Victorian choralism. In two introductory historiographic chapters I outline the political-narrative strategies by which both Victorian and black South African choralism have been elided from music histories. Part 1 gives an account of the "structures" within and through which choralism functioned as a practice of colonisation, as "internal colonialism" in Britain and evangelical colonialism in the eastern Cape Colony. In chapter 1 I suggest that the religious contexts within which choralism operated, including the music theoretical construction of the tonic sol-fa notation and method as "natural", and the "scientific" musicalisation of race, constituted conditions for the foreign mission's embrace of choralism. The second chapter explores further such affinities, tracing sol-fa choralism's institutional affiliations with nineteenth-century "reform" movements, and suggesting that sol-fa's practices worked in fulfilment of core reformist concerns such as "industry" and literacy. Throughout, the thesis explores how the categories of class and race functioned interchangeably in the colonial imagination. Chapter 3 charts this relationship in the terrain of music education; notations, for instance, which were classed in Britain, became racialised in colonial South Africa. In particular I show that black music education operated within colonial racial discourses. Chapter 4 is a reading of Victorian choralism as a "discipline", interpreting choral performance practice and choral music itself as disciplinary acts which complemented the political contexts in which choralism operated. Part 1, in short, explores how popular choralism operated within and as dominant politicking. In part 2 I turn to the black reception of Victorian choralism in composition and performance. The fifth chapter examines the compositional discourse of early black choral music, focussing on the work of John Knox Bokwe (1855-1922). Through a detailed account of several of Bokwe's works and their metropolitan sources, particularly late-nineteenth century gospel hymnody, I show that Bokwe's compositional practice enacted a politics that became anticolonial, and that early black choral music became "black" in its reception. I conclude that ethno/musicological claims that early black choral music contains "African" musical content conflate "race" and culture under a double imperative: in the names of a decolonising politics and a postcolonial epistemology in which hybridity as resistance is racialised. The final chapter explores how "the voice" was crucial to identity politics in the Victorian world, an object that was classed and racialised. Proceeding from the black reception of choral voice training, I attempt to outline the beginnings of a social history of the black choral voice, as well as analyse the sonic content of that voice through an approach I call a "phonetics of timbre".
- Full Text:
- Date Issued: 2004
- Authors: Olwage, Grant
- Date: 2004
- Subjects: Choral music -- South Africa -- History Black people -- South Africa -- Music -- History and criticism Bokwe, John Knox, 1855-1922
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2679 , http://hdl.handle.net/10962/d1007717
- Description: This thesis explores the genesis of black choralism in late-nineteenth-century colonial South Africa, attending specifically to its dialectic with metropolitan Victorian choralism. In two introductory historiographic chapters I outline the political-narrative strategies by which both Victorian and black South African choralism have been elided from music histories. Part 1 gives an account of the "structures" within and through which choralism functioned as a practice of colonisation, as "internal colonialism" in Britain and evangelical colonialism in the eastern Cape Colony. In chapter 1 I suggest that the religious contexts within which choralism operated, including the music theoretical construction of the tonic sol-fa notation and method as "natural", and the "scientific" musicalisation of race, constituted conditions for the foreign mission's embrace of choralism. The second chapter explores further such affinities, tracing sol-fa choralism's institutional affiliations with nineteenth-century "reform" movements, and suggesting that sol-fa's practices worked in fulfilment of core reformist concerns such as "industry" and literacy. Throughout, the thesis explores how the categories of class and race functioned interchangeably in the colonial imagination. Chapter 3 charts this relationship in the terrain of music education; notations, for instance, which were classed in Britain, became racialised in colonial South Africa. In particular I show that black music education operated within colonial racial discourses. Chapter 4 is a reading of Victorian choralism as a "discipline", interpreting choral performance practice and choral music itself as disciplinary acts which complemented the political contexts in which choralism operated. Part 1, in short, explores how popular choralism operated within and as dominant politicking. In part 2 I turn to the black reception of Victorian choralism in composition and performance. The fifth chapter examines the compositional discourse of early black choral music, focussing on the work of John Knox Bokwe (1855-1922). Through a detailed account of several of Bokwe's works and their metropolitan sources, particularly late-nineteenth century gospel hymnody, I show that Bokwe's compositional practice enacted a politics that became anticolonial, and that early black choral music became "black" in its reception. I conclude that ethno/musicological claims that early black choral music contains "African" musical content conflate "race" and culture under a double imperative: in the names of a decolonising politics and a postcolonial epistemology in which hybridity as resistance is racialised. The final chapter explores how "the voice" was crucial to identity politics in the Victorian world, an object that was classed and racialised. Proceeding from the black reception of choral voice training, I attempt to outline the beginnings of a social history of the black choral voice, as well as analyse the sonic content of that voice through an approach I call a "phonetics of timbre".
- Full Text:
- Date Issued: 2004
Mycorrhizal status of indigenous tree species in a forest biome of the Eastern Cape, South Africa
- Hawley, Greer L, Dames, Joanna F
- Authors: Hawley, Greer L , Dames, Joanna F
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6458 , http://hdl.handle.net/10962/d1005774
- Description: Mycorrhizal fungi are intimately associated with plant roots, affecting plant growth, health and increasing the plants' tolerance to environmental stress. Several mycorrhizal types are recognized based primarily on morphological characteristics within plant roots. When considering propagation and management of an indigenous plant species, it is essential to know its mycorrhizal status. Root samples from 17 tree species common to the pockets of forest in the Eastern Cape province, and representing the families Rubiaceae, Scrophulariaceae, Oleaceae, Podocarpaceae, Myrsinaceae, Anacardiaceae, Caesalpinoideae, Papilionoideae, Rutaceae, Meliaceae, Celastraceae, Flacouticeae and Ebenaceae, were sampled and examined for mycorrhizal colonization. Microscopic examination of all the species produced evidence of morphological structures indicative of endomycorrhizal associations as indicated by the presence of intercellular hyphae combined with vesicles, arbuscules or hyphal coils. Hyphal coils (also known as Paris-type associations) appeared to be abundant, especially within the Cassine genus. Arbuscules (also known as Arum-type associations) were scarce but sometimes present, and vesicles were prolific in Olea capensis. Most of the tree species examined have been assigned arbuscular mycorrhizal status. No ectomycorrhizal associations were recorded
- Full Text:
- Date Issued: 2004
- Authors: Hawley, Greer L , Dames, Joanna F
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6458 , http://hdl.handle.net/10962/d1005774
- Description: Mycorrhizal fungi are intimately associated with plant roots, affecting plant growth, health and increasing the plants' tolerance to environmental stress. Several mycorrhizal types are recognized based primarily on morphological characteristics within plant roots. When considering propagation and management of an indigenous plant species, it is essential to know its mycorrhizal status. Root samples from 17 tree species common to the pockets of forest in the Eastern Cape province, and representing the families Rubiaceae, Scrophulariaceae, Oleaceae, Podocarpaceae, Myrsinaceae, Anacardiaceae, Caesalpinoideae, Papilionoideae, Rutaceae, Meliaceae, Celastraceae, Flacouticeae and Ebenaceae, were sampled and examined for mycorrhizal colonization. Microscopic examination of all the species produced evidence of morphological structures indicative of endomycorrhizal associations as indicated by the presence of intercellular hyphae combined with vesicles, arbuscules or hyphal coils. Hyphal coils (also known as Paris-type associations) appeared to be abundant, especially within the Cassine genus. Arbuscules (also known as Arum-type associations) were scarce but sometimes present, and vesicles were prolific in Olea capensis. Most of the tree species examined have been assigned arbuscular mycorrhizal status. No ectomycorrhizal associations were recorded
- Full Text:
- Date Issued: 2004
Neural network-based ionospheric modelling over the South African region
- McKinnell, Lee-Anne, Poole, Allon W V
- Authors: McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6795 , http://hdl.handle.net/10962/d1003839
- Description: During the past decade, South African scientists have pioneered research in the field of ionospheric modelling using the technique of neural networks (NNs). Global ionospheric models have always been insufficient for the South African region owing to an historical paucity of available data. Within the past 10 years, however, three new ionospheric sounders have been installed locally and are operating continuously. These sounders are located at Grahamstown (33.3°S, 26.5°E), Louisvale (28.5°S, 21.2°E) and Madimbo (22.4°S, 30.9°E). The addition of a modern sounder at Grahamstown enlarged the ionospheric database for this station to 30 years, making this archive a considerable asset for ionospheric research. Quality control and online availability of the data has also added to its attraction. An important requirement for empirical modelling, but especially for employing NNs, is a large database describing the history of the relationship between the ionosphere and the geophysical parameters that define its behaviour. This review describes the path of South African ionospheric modelling over the past 10 years, the role of NNs in this development, the international collaborations that have arisen from this, and the future of ionospheric modelling in South Africa.
- Full Text:
- Date Issued: 2004
- Authors: McKinnell, Lee-Anne , Poole, Allon W V
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6795 , http://hdl.handle.net/10962/d1003839
- Description: During the past decade, South African scientists have pioneered research in the field of ionospheric modelling using the technique of neural networks (NNs). Global ionospheric models have always been insufficient for the South African region owing to an historical paucity of available data. Within the past 10 years, however, three new ionospheric sounders have been installed locally and are operating continuously. These sounders are located at Grahamstown (33.3°S, 26.5°E), Louisvale (28.5°S, 21.2°E) and Madimbo (22.4°S, 30.9°E). The addition of a modern sounder at Grahamstown enlarged the ionospheric database for this station to 30 years, making this archive a considerable asset for ionospheric research. Quality control and online availability of the data has also added to its attraction. An important requirement for empirical modelling, but especially for employing NNs, is a large database describing the history of the relationship between the ionosphere and the geophysical parameters that define its behaviour. This review describes the path of South African ionospheric modelling over the past 10 years, the role of NNs in this development, the international collaborations that have arisen from this, and the future of ionospheric modelling in South Africa.
- Full Text:
- Date Issued: 2004
Nuclear translocation of the Hsp70/Hsp90 organizing protein mSTI1 is regulated by cell cycle kinases
- Longshaw, Victoria M, Chapple, J Paul, Cheetham, Michael E, Blatch, Gregory L
- Authors: Longshaw, Victoria M , Chapple, J Paul , Cheetham, Michael E , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6488 , http://hdl.handle.net/10962/d1006271 , https://dx.doi.org/10.1242/jcs.00905
- Description: The co-chaperone murine stress-inducible protein 1 (mSTI1), an Hsp70/Hsp90 organizing protein (Hop) homologue, mediates the assembly of the Hsp70/Hsp90 chaperone heterocomplex. The mSTI1 protein can be phosphorylated in vitro by cell cycle kinases proximal to a putative nuclear localization signal (NLS), which substantiated a predicted casein kinase II (CKII)-cdc2 kinase-NLS (CcN) motif at position 180-239 and suggested that mSTI1 might move between the cytoplasm and the nucleus under certain cell cycle conditions. The mechanism responsible for the cellular localization of mSTI1 was probed using NIH3T3 fibroblasts to investigate the localization of endogenous mSTI1 and enhanced green fluorescent protein (EGFP)-tagged mSTI1 mutants. Localization studies on cell lines stably expressing NLS(mSTI1)-EGFP and EGFP demonstrated that the NLS(mSTI1) was able to promote a nuclear localization of EGFP. The mSTI1 protein was exclusively cytoplasmic in most cells under normal conditions but was present in the nucleus of a subpopulation of cells and accumulated in the nucleus following inhibition of nuclear export (leptomycin B treatment). G1/S-phase arrest (using hydroxyurea) and inhibition of cdc2 kinase (using olomoucine) but not inhibition of casein kinase II (using 5,6-dichlorobenzimidazole riboside), increased the proportion of cells with endogenous mSTI1 nuclear staining. mSTI1-EGFP behaved identically to endogenous mSTI1. The functional importance of key residues was tested using modified mSTI1-EGFP proteins. Inactivation and phosphorylation mimicking of potential phosphorylation sites in mSTI1 altered the nuclear translocation. Mimicking of phosphorylation at the mSTI1 CKII phosphorylation site (S189E) promoted nuclear localization of mSTI1-EGFP. Mimicking phosphorylation at the cdc2 kinase phosphorylation site (T198E) promoted cytoplasmic localization of mSTI1-EGFP at the G1/S-phase transition,whereas removal of this site (T198A) promoted the nuclear localization of mSTI1-EGFP under the same conditions. These data provide the first evidence of nuclear import and export of a major Hsp70/Hsp90 co-chaperone and the regulation of this nuclear-cytoplasmic shuttling by cell cycle status and cell cycle kinases.
- Full Text:
- Date Issued: 2004
Nuclear translocation of the Hsp70/Hsp90 organizing protein mSTI1 is regulated by cell cycle kinases
- Authors: Longshaw, Victoria M , Chapple, J Paul , Cheetham, Michael E , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6488 , http://hdl.handle.net/10962/d1006271 , https://dx.doi.org/10.1242/jcs.00905
- Description: The co-chaperone murine stress-inducible protein 1 (mSTI1), an Hsp70/Hsp90 organizing protein (Hop) homologue, mediates the assembly of the Hsp70/Hsp90 chaperone heterocomplex. The mSTI1 protein can be phosphorylated in vitro by cell cycle kinases proximal to a putative nuclear localization signal (NLS), which substantiated a predicted casein kinase II (CKII)-cdc2 kinase-NLS (CcN) motif at position 180-239 and suggested that mSTI1 might move between the cytoplasm and the nucleus under certain cell cycle conditions. The mechanism responsible for the cellular localization of mSTI1 was probed using NIH3T3 fibroblasts to investigate the localization of endogenous mSTI1 and enhanced green fluorescent protein (EGFP)-tagged mSTI1 mutants. Localization studies on cell lines stably expressing NLS(mSTI1)-EGFP and EGFP demonstrated that the NLS(mSTI1) was able to promote a nuclear localization of EGFP. The mSTI1 protein was exclusively cytoplasmic in most cells under normal conditions but was present in the nucleus of a subpopulation of cells and accumulated in the nucleus following inhibition of nuclear export (leptomycin B treatment). G1/S-phase arrest (using hydroxyurea) and inhibition of cdc2 kinase (using olomoucine) but not inhibition of casein kinase II (using 5,6-dichlorobenzimidazole riboside), increased the proportion of cells with endogenous mSTI1 nuclear staining. mSTI1-EGFP behaved identically to endogenous mSTI1. The functional importance of key residues was tested using modified mSTI1-EGFP proteins. Inactivation and phosphorylation mimicking of potential phosphorylation sites in mSTI1 altered the nuclear translocation. Mimicking of phosphorylation at the mSTI1 CKII phosphorylation site (S189E) promoted nuclear localization of mSTI1-EGFP. Mimicking phosphorylation at the cdc2 kinase phosphorylation site (T198E) promoted cytoplasmic localization of mSTI1-EGFP at the G1/S-phase transition,whereas removal of this site (T198A) promoted the nuclear localization of mSTI1-EGFP under the same conditions. These data provide the first evidence of nuclear import and export of a major Hsp70/Hsp90 co-chaperone and the regulation of this nuclear-cytoplasmic shuttling by cell cycle status and cell cycle kinases.
- Full Text:
- Date Issued: 2004
Occupational aspirations and gender stereotyping of Xhosa-speaking senior primary learners
- Authors: Els, Catherine
- Date: 2004
- Subjects: Vocational interests -- South Africa -- Research , Gender identity , School children -- South Africa -- Attitudes , Xhosa (African people) -- Attitudes
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11020 , http://hdl.handle.net/10948/325 , Vocational interests -- South Africa -- Research , Gender identity , School children -- South Africa -- Attitudes , Xhosa (African people) -- Attitudes
- Description: International research highlights conflicting results regarding factors that could play a role in the development of occupational aspirations and occupational gender stereotyping of primary school children. Some of the variables that have been identified are age, gender, ethnicity, socioeconomic status and societal influences. There has been some research emphasis on the career development of South Africans. However, studies that have been conducted have focused mainly on adolescents and adults. Furthermore, the majority of this research has focused on programme intervention and not on acquiring baseline information. There has been no research to date on the career development of South African Xhosa-speaking senior primary school children. The lack of career research on South African Xhosa-speaking children indicates the need for the present research. This study aims to describe and compare the occupational aspirations and occupational gender stereotyping (in terms of Holland’s occupational and status level typology) of male and female Xhosa-speaking senior primary school learners. The study also describes the possible gender stereotypical perceptions preadolescent children hold regarding certain occupations. A non-probability sample of 274 Xhosa-speaking children between the ages of 10 and 14 years was drawn from two primary schools in townships in the Nelson Mandela Metropole. An exploratory and descriptive research framework was utilised, with descriptive statistical procedures employed to summarise and report the data in a meaningful manner. The major findings of the present study indicate that Xhosa-speaking senior primary school children’s favourite occupational aspirations fit into Holland’s Investigative typology and high status level. Some gender differences were evident, with slightly more boys aspiring to Investigative occupations than girls. Both boys and girls demonstrated gender stereotypical perceptions regarding xiii which occupations were suitable for both genders, with boys more willing to accept girls into traditional male occupations than girls willing to accept boys into traditional female occupations. The results of the present study emphasise the need for further exploration of the occupational aspirations and occupational ge nder stereotyping of Xhosa-speaking senior primary school children. Future research needs to include other cultural and age groups in order to explore how personal and situational variables may differentially influence children’s occupational aspirations and occupational gender stereotyping.
- Full Text:
- Date Issued: 2004
- Authors: Els, Catherine
- Date: 2004
- Subjects: Vocational interests -- South Africa -- Research , Gender identity , School children -- South Africa -- Attitudes , Xhosa (African people) -- Attitudes
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:11020 , http://hdl.handle.net/10948/325 , Vocational interests -- South Africa -- Research , Gender identity , School children -- South Africa -- Attitudes , Xhosa (African people) -- Attitudes
- Description: International research highlights conflicting results regarding factors that could play a role in the development of occupational aspirations and occupational gender stereotyping of primary school children. Some of the variables that have been identified are age, gender, ethnicity, socioeconomic status and societal influences. There has been some research emphasis on the career development of South Africans. However, studies that have been conducted have focused mainly on adolescents and adults. Furthermore, the majority of this research has focused on programme intervention and not on acquiring baseline information. There has been no research to date on the career development of South African Xhosa-speaking senior primary school children. The lack of career research on South African Xhosa-speaking children indicates the need for the present research. This study aims to describe and compare the occupational aspirations and occupational gender stereotyping (in terms of Holland’s occupational and status level typology) of male and female Xhosa-speaking senior primary school learners. The study also describes the possible gender stereotypical perceptions preadolescent children hold regarding certain occupations. A non-probability sample of 274 Xhosa-speaking children between the ages of 10 and 14 years was drawn from two primary schools in townships in the Nelson Mandela Metropole. An exploratory and descriptive research framework was utilised, with descriptive statistical procedures employed to summarise and report the data in a meaningful manner. The major findings of the present study indicate that Xhosa-speaking senior primary school children’s favourite occupational aspirations fit into Holland’s Investigative typology and high status level. Some gender differences were evident, with slightly more boys aspiring to Investigative occupations than girls. Both boys and girls demonstrated gender stereotypical perceptions regarding xiii which occupations were suitable for both genders, with boys more willing to accept girls into traditional male occupations than girls willing to accept boys into traditional female occupations. The results of the present study emphasise the need for further exploration of the occupational aspirations and occupational ge nder stereotyping of Xhosa-speaking senior primary school children. Future research needs to include other cultural and age groups in order to explore how personal and situational variables may differentially influence children’s occupational aspirations and occupational gender stereotyping.
- Full Text:
- Date Issued: 2004
Oh! yini yinikangaka
- Rodolo, L. S., Dubeni, N., Mgidi, A., Tshona, S. S., Composer not specified, Dargie, Dave
- Authors: Rodolo, L. S. , Dubeni, N. , Mgidi, A. , Tshona, S. S. , Composer not specified , Dargie, Dave
- Date: 2004
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Alice sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343256 , vital:62989 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC344b-02
- Description: UFH music students accompanied by different types of marimba
- Full Text: false
- Date Issued: 2004
- Authors: Rodolo, L. S. , Dubeni, N. , Mgidi, A. , Tshona, S. S. , Composer not specified , Dargie, Dave
- Date: 2004
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Alice sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343256 , vital:62989 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC344b-02
- Description: UFH music students accompanied by different types of marimba
- Full Text: false
- Date Issued: 2004
Oliver Tambo
- Nduna, S., Mgidi, A., Dubeni, N., Rodolo, L. S., Mngesi, N. M., Mgeni, N., Dubeni, T., Letsika, S. T., Hangana, S., Mgidi, A. T. V., Composer not specified, Dargie, Dave
- Authors: Nduna, S. , Mgidi, A. , Dubeni, N. , Rodolo, L. S. , Mngesi, N. M. , Mgeni, N. , Dubeni, T. , Letsika, S. T. , Hangana, S. , Mgidi, A. T. V. , Composer not specified , Dargie, Dave
- Date: 2004
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Alice sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343221 , vital:62983 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC344a-09
- Description: UFH music students accompanied by different types of marimba
- Full Text: false
- Date Issued: 2004
- Authors: Nduna, S. , Mgidi, A. , Dubeni, N. , Rodolo, L. S. , Mngesi, N. M. , Mgeni, N. , Dubeni, T. , Letsika, S. T. , Hangana, S. , Mgidi, A. T. V. , Composer not specified , Dargie, Dave
- Date: 2004
- Subjects: Folk music , Sacred music , Field recordings , Africa, Sub-Saharan , Africa South Africa Alice sa
- Language: IsiXhosa
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/343221 , vital:62983 , International Library of African Music, Rhodes University, Makhanda, South Africa , Dave Dargie Field Tapes, Rhodes University, Makhanda, South Africa , DDC344a-09
- Description: UFH music students accompanied by different types of marimba
- Full Text: false
- Date Issued: 2004
On becoming an African-Asian English academic at Rhodes University
- Authors: Naidu, Samantha
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:21926 , http://hdl.handle.net/10962/14392 , https://0-www.jstor.org.wam.seals.ac.za/stable/24487641
- Description: preprint , I arrived at Rhodes University English Department with not much more than a passion for literature. During the last fourteen years I have been able to observe the discipline in operation. My perspective has broadened and deepened, taking in the trajectory from Stanley Kidd and the colonial Cambridge practices, and from what might be termed the 'humanist enterprise of English studies', 1 to the white liberalism of Guy Butler in the middle of the twentieth century, then to the present post-apartheid era of humanities cutbacks and increasing commodification of knowledge.
- Full Text:
- Date Issued: 2004
- Authors: Naidu, Samantha
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:21926 , http://hdl.handle.net/10962/14392 , https://0-www.jstor.org.wam.seals.ac.za/stable/24487641
- Description: preprint , I arrived at Rhodes University English Department with not much more than a passion for literature. During the last fourteen years I have been able to observe the discipline in operation. My perspective has broadened and deepened, taking in the trajectory from Stanley Kidd and the colonial Cambridge practices, and from what might be termed the 'humanist enterprise of English studies', 1 to the white liberalism of Guy Butler in the middle of the twentieth century, then to the present post-apartheid era of humanities cutbacks and increasing commodification of knowledge.
- Full Text:
- Date Issued: 2004
On the mocvd growth of ZnO
- Authors: Pagni, Olivier Demeno
- Date: 2004
- Subjects: Zinc oxide thin films , Metal organic chemical vapor deposition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11075 , http://hdl.handle.net/10948/382 , Zinc oxide thin films , Metal organic chemical vapor deposition
- Description: Zinc oxide (ZnO) is a II-VI semiconductor material that offers tremendous potential as a light emitter in the blue-to-UV range. It has a wurtzite structure, and a direct band gap that can be tuned from 3.0 to 4.0 eV by alloying with Cd or Mg, respectively. In this work, ZnO thin films were grown by metalorganic chemical vapor deposition (MOCVD) on n-Si 2 ° off (100), amorphous glass, n-GaAs (100), and c-plane sapphire substrates. Diethyl zinc (DEZn) and tert-butanol (TBOH) were chosen as precursors. For the first time, Second Harmonic Generation Imaging was applied to the mapping of ZnO epilayers. The images obtained highlighted the polycrystalline character of the thin films, and provided insight as to the growth mode of ZnO on Si. The influence of substrate temperature on the structural properties of the epilayers was investigated by X-ray diffraction and optical microscopy. Grain sizes as high as 54 nm were measured. The optimum temperature range for this system proved to be 450 – 500 °C. The influence of the VI:II ratio during growth on the optical properties of the epilayers was studied by UV-vis-near IR spectroscopy. The lowest Urbach tail E0 parameter was measured for material grown at a VI:II ratio of 18:1. The films’ free electron concentration was shown to decrease by over two orders of magnitude, from 1019 to 1017 cm-3, as the VI:II ratio increased from 10 to 60:1. This decrease in carrier concentration with rising VI:II ratio was paralleled to the surge at 12 K of a photoluminescence (PL) emission band characteristic of p-type ZnO. The band gap energies extracted from room temperature transmission spectra ranged between 3.35 and 3.38 eV, in agreement with the value of 3.35 eV measured by room temperature PL. Moreover, variable temperature PL spectra were recorded between 12 and 298 K on ZnO grown on Si. The 12 K spectrum was dominated by a donor-bound exciton (D°X) at 3.36 eV, while the 298 K scan displayed strong free exciton emission (FX) at 3.29 eV. The width of the D°X band proved to be as narrow as 7 meV. The intensity ratio between the room temperature near-band edge emission and the defect-related green band was as high as 28:1, highlighting the optical quality of the layers deposited in this work. The electrical properties of the thin films were studied by Hall measurements (van der Pauw configuration), and a maximum room temperature mobility of 11 cm2/Vs was recorded. Furthermore, a palladium (Pd) Schottky barrier diode on ZnO was fabricated. The barrier height and ideality factor were calculated from current–voltage measurements to be 0.83 eV and 1.6, respectively. The capacitance–voltage curve of the diode yielded a carrier concentration in the depletion region of 8·1017 cm-3. This study has shown that the optical and electrical properties of ZnO depend strongly on the growth conditions employed. A suitable choice of growth parameters can yield high quality ZnO that may be used for various devices. Keywords: Hall, MOCVD, optical spectroscopy, photoluminescence, Schottky barrier diode, SH Imaging, X-ray diffraction, ZnO.
- Full Text:
- Date Issued: 2004
- Authors: Pagni, Olivier Demeno
- Date: 2004
- Subjects: Zinc oxide thin films , Metal organic chemical vapor deposition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11075 , http://hdl.handle.net/10948/382 , Zinc oxide thin films , Metal organic chemical vapor deposition
- Description: Zinc oxide (ZnO) is a II-VI semiconductor material that offers tremendous potential as a light emitter in the blue-to-UV range. It has a wurtzite structure, and a direct band gap that can be tuned from 3.0 to 4.0 eV by alloying with Cd or Mg, respectively. In this work, ZnO thin films were grown by metalorganic chemical vapor deposition (MOCVD) on n-Si 2 ° off (100), amorphous glass, n-GaAs (100), and c-plane sapphire substrates. Diethyl zinc (DEZn) and tert-butanol (TBOH) were chosen as precursors. For the first time, Second Harmonic Generation Imaging was applied to the mapping of ZnO epilayers. The images obtained highlighted the polycrystalline character of the thin films, and provided insight as to the growth mode of ZnO on Si. The influence of substrate temperature on the structural properties of the epilayers was investigated by X-ray diffraction and optical microscopy. Grain sizes as high as 54 nm were measured. The optimum temperature range for this system proved to be 450 – 500 °C. The influence of the VI:II ratio during growth on the optical properties of the epilayers was studied by UV-vis-near IR spectroscopy. The lowest Urbach tail E0 parameter was measured for material grown at a VI:II ratio of 18:1. The films’ free electron concentration was shown to decrease by over two orders of magnitude, from 1019 to 1017 cm-3, as the VI:II ratio increased from 10 to 60:1. This decrease in carrier concentration with rising VI:II ratio was paralleled to the surge at 12 K of a photoluminescence (PL) emission band characteristic of p-type ZnO. The band gap energies extracted from room temperature transmission spectra ranged between 3.35 and 3.38 eV, in agreement with the value of 3.35 eV measured by room temperature PL. Moreover, variable temperature PL spectra were recorded between 12 and 298 K on ZnO grown on Si. The 12 K spectrum was dominated by a donor-bound exciton (D°X) at 3.36 eV, while the 298 K scan displayed strong free exciton emission (FX) at 3.29 eV. The width of the D°X band proved to be as narrow as 7 meV. The intensity ratio between the room temperature near-band edge emission and the defect-related green band was as high as 28:1, highlighting the optical quality of the layers deposited in this work. The electrical properties of the thin films were studied by Hall measurements (van der Pauw configuration), and a maximum room temperature mobility of 11 cm2/Vs was recorded. Furthermore, a palladium (Pd) Schottky barrier diode on ZnO was fabricated. The barrier height and ideality factor were calculated from current–voltage measurements to be 0.83 eV and 1.6, respectively. The capacitance–voltage curve of the diode yielded a carrier concentration in the depletion region of 8·1017 cm-3. This study has shown that the optical and electrical properties of ZnO depend strongly on the growth conditions employed. A suitable choice of growth parameters can yield high quality ZnO that may be used for various devices. Keywords: Hall, MOCVD, optical spectroscopy, photoluminescence, Schottky barrier diode, SH Imaging, X-ray diffraction, ZnO.
- Full Text:
- Date Issued: 2004
One hundred years of botany at Rhodes University
- Authors: Lubke, Roy , Brink, Estelle
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6523 , http://hdl.handle.net/10962/d1005954
- Description: The Botany Department of Rhodes University is located in the historic Schonland Building. An indigenous garden was created in its courtyard, mainly of species of the Eastern Cape province, and its growth in diversity and stature mirrors the changes in the department over the years. Professor Selmar Schonland, the founding father of botany at Rhodes, was also the curator/director of the Albany Museum. Under his leadership, systematics was firmly established as a discipline at Rhodes and research on the flora of the Eastern Cape begun, to be continued to this day. Under professors William Isaac (1949–1951) and Edgar Twyman (1951–1973), plant physiology became an important area of study, and future leaders in physiology at other universities obtained degrees under them. Phycology and aquatic ecology became notable disciplines with Mary Pocock’s world-class work in the 1940s on freshwater and marine algae, which inspired others such as head of department Professor Stanley Seagrief (1958–1986) to develop these studies further. Mycology and microbiology were established as major subdisciplines under Noel Smith (1926–1948) and Twyman through to the 1960s, when the Department of Microbiology was established. Early studies in ecology owe their success to Tony Martin (1947–1956) and the link with the Grahamstown Botanical Research Station, when a sound base for plant ecology in the Eastern Cape was established. Coastal ecology became a major focus in the 1970s, when Roy Lubke and Ted Avis concentrated on dunes and the management of coastal regions. This led to the establishment of the Department of Environmental Science in the 1990s. The expertise of the botany staff in teaching and research in a variety of fields is reflected in the careers of its many students around the world.
- Full Text:
- Date Issued: 2004
- Authors: Lubke, Roy , Brink, Estelle
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6523 , http://hdl.handle.net/10962/d1005954
- Description: The Botany Department of Rhodes University is located in the historic Schonland Building. An indigenous garden was created in its courtyard, mainly of species of the Eastern Cape province, and its growth in diversity and stature mirrors the changes in the department over the years. Professor Selmar Schonland, the founding father of botany at Rhodes, was also the curator/director of the Albany Museum. Under his leadership, systematics was firmly established as a discipline at Rhodes and research on the flora of the Eastern Cape begun, to be continued to this day. Under professors William Isaac (1949–1951) and Edgar Twyman (1951–1973), plant physiology became an important area of study, and future leaders in physiology at other universities obtained degrees under them. Phycology and aquatic ecology became notable disciplines with Mary Pocock’s world-class work in the 1940s on freshwater and marine algae, which inspired others such as head of department Professor Stanley Seagrief (1958–1986) to develop these studies further. Mycology and microbiology were established as major subdisciplines under Noel Smith (1926–1948) and Twyman through to the 1960s, when the Department of Microbiology was established. Early studies in ecology owe their success to Tony Martin (1947–1956) and the link with the Grahamstown Botanical Research Station, when a sound base for plant ecology in the Eastern Cape was established. Coastal ecology became a major focus in the 1970s, when Roy Lubke and Ted Avis concentrated on dunes and the management of coastal regions. This led to the establishment of the Department of Environmental Science in the 1990s. The expertise of the botany staff in teaching and research in a variety of fields is reflected in the careers of its many students around the world.
- Full Text:
- Date Issued: 2004
Oomashayela phezulu:
- Mazibuko, Nokuthula, Kaschula, Russell H
- Authors: Mazibuko, Nokuthula , Kaschula, Russell H
- Date: 2004
- Language: Zulu
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175323 , vital:42565 , ISBN 9781869284251
- Description: ‘Sam, khawuphole maan, thob'umoya. KungoLwesihlanu namhlanje, sakuba nalo ithuba elininzi ngomso lokuzithethelela ebazalini bethu! Ha, ha, ha!'wagigitheka uBrunette'Thatha nantsi icider, usele!'UBrunette wayonwabile, wayekuthanda futhi ekonwabela ngoku ukusela, kwaye ezi iicider zazingavakali ngathi butywala! Wayeziva efanelekile kwibhulukhwe yakhe ebomvu, ethe nca kuye emzimbeni kakuhle, nehempe awayeyinxibe ngentla ehambelana nayo, nezihlangu ezichophileyo awayezinxibile. Wagqiba kwangexesha ukuphotha iinwele zakhe ngoboya bomsila wehashe, elungele ipati eyayiza kuba ngobo busuku. Yayintle into yokuba abe woluka iinwele zabantu. Ngokwenza njalo wayezenzela.
- Full Text:
- Date Issued: 2004
- Authors: Mazibuko, Nokuthula , Kaschula, Russell H
- Date: 2004
- Language: Zulu
- Type: text , book
- Identifier: http://hdl.handle.net/10962/175323 , vital:42565 , ISBN 9781869284251
- Description: ‘Sam, khawuphole maan, thob'umoya. KungoLwesihlanu namhlanje, sakuba nalo ithuba elininzi ngomso lokuzithethelela ebazalini bethu! Ha, ha, ha!'wagigitheka uBrunette'Thatha nantsi icider, usele!'UBrunette wayonwabile, wayekuthanda futhi ekonwabela ngoku ukusela, kwaye ezi iicider zazingavakali ngathi butywala! Wayeziva efanelekile kwibhulukhwe yakhe ebomvu, ethe nca kuye emzimbeni kakuhle, nehempe awayeyinxibe ngentla ehambelana nayo, nezihlangu ezichophileyo awayezinxibile. Wagqiba kwangexesha ukuphotha iinwele zakhe ngoboya bomsila wehashe, elungele ipati eyayiza kuba ngobo busuku. Yayintle into yokuba abe woluka iinwele zabantu. Ngokwenza njalo wayezenzela.
- Full Text:
- Date Issued: 2004
Optimization of a manufacturing process for atrazine with a focus on waste minimization
- Authors: Mtyopo, Mteteleli Bethwell
- Date: 2004
- Subjects: Waste minimization , Atrazine -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10976 , http://hdl.handle.net/10948/259 , Waste minimization , Atrazine -- Environmental aspects
- Description: Chemical synthesis is not complete without waste treatment. There is no chemical process that does not produce waste. The untreated effluent discharged by chemical industries poses a major environmental concern. This dissertation describes the results of an investigation carried out on the formation of by-products (impurities) during the synthesis of atrazine by neutralization of the reaction mixture during the actual synthesis procedure, and prior to disposal using carbon dioxide or hydrochloric acid. The main objectives for the said investigation were: {u100083} To optimise the reaction parameters to obtain a higher yield and purity of atrazine. {u100083} To evaluate the use of carbon dioxide and hydrochloric acid to neutralise the reaction mixture. {u100083} To study the solids present in the effluent. Synthetic reactions were carried out in the presence of an organic solvent, methyl isobutyl ketone (MIBK). The synthesis of atrazine was optimised in terms of addition sequence and rates of amine reagents and base (proton acceptor) additions by means of bench scale reactions. It was found that addition of a neutralising step (hydrochloric acid or carbon dioxide) to neutralise the basic reaction mixture prior to and after addition of the secondary amine and the base minimizes the formation of by-products. Of particular importance in ensuring high yields and selectivity to the atrazine product was temperature control, pH control, reagent ratios, addition rates and mixing. The latter was important in view of the rapid reaction of amine/NaOH with cyanuric chloride, as well as the possible reaction of mono-i, the reaction intermediate, with IPA in cases of excesses of reagent. Under optimum conditions, an atrazine composition of >97% was achieved where the resultant product was well within stipulated product specifications.
- Full Text:
- Date Issued: 2004
- Authors: Mtyopo, Mteteleli Bethwell
- Date: 2004
- Subjects: Waste minimization , Atrazine -- Environmental aspects
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10976 , http://hdl.handle.net/10948/259 , Waste minimization , Atrazine -- Environmental aspects
- Description: Chemical synthesis is not complete without waste treatment. There is no chemical process that does not produce waste. The untreated effluent discharged by chemical industries poses a major environmental concern. This dissertation describes the results of an investigation carried out on the formation of by-products (impurities) during the synthesis of atrazine by neutralization of the reaction mixture during the actual synthesis procedure, and prior to disposal using carbon dioxide or hydrochloric acid. The main objectives for the said investigation were: {u100083} To optimise the reaction parameters to obtain a higher yield and purity of atrazine. {u100083} To evaluate the use of carbon dioxide and hydrochloric acid to neutralise the reaction mixture. {u100083} To study the solids present in the effluent. Synthetic reactions were carried out in the presence of an organic solvent, methyl isobutyl ketone (MIBK). The synthesis of atrazine was optimised in terms of addition sequence and rates of amine reagents and base (proton acceptor) additions by means of bench scale reactions. It was found that addition of a neutralising step (hydrochloric acid or carbon dioxide) to neutralise the basic reaction mixture prior to and after addition of the secondary amine and the base minimizes the formation of by-products. Of particular importance in ensuring high yields and selectivity to the atrazine product was temperature control, pH control, reagent ratios, addition rates and mixing. The latter was important in view of the rapid reaction of amine/NaOH with cyanuric chloride, as well as the possible reaction of mono-i, the reaction intermediate, with IPA in cases of excesses of reagent. Under optimum conditions, an atrazine composition of >97% was achieved where the resultant product was well within stipulated product specifications.
- Full Text:
- Date Issued: 2004