The natural product chemistry of South African Plocamium species
- Authors: Knott, Michael George
- Date: 2003
- Subjects: Marine algae -- South Africa Red algae -- South Africa Green algae -- South Africa Halimeda -- South Africa
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3820 , http://hdl.handle.net/10962/d1004920
- Description: The brine shrimp lethality assay was used as a preliminary tool to screen eighteen seaweeds collected from the South African coast. Of the seaweeds tested, the red algae Plocamium corallorhiza and Hypnea rosea, and the green alga Halimeda sp., showed the most potent activity. The chemical investigation of P. corallorhiza resulted in the isolation and structural elucidation of five previously undescribed secondary metabolites, along with three known compounds and four possible artifacts of the extraction process. Standard spectroscopic methods and comparison with known compounds were used to determine the structures of the new metabolites. The new compounds included the linear halogenated monoterpenes 4,8-dibromo-1, 1-dichloro-3,7-dimethyl-2,6-octadiene (99), 4,6-dibromo-l, 1-dichloro-3,7-dimethyl-2,7-octadiene (100), 4,8-dibromo-l, 1,7-trichloro-3,7-dimethyl-2,5-octadiene (101) and 3,4,6,7-tetrachloro-3,7-dimethyl-l-octene (102) and the cyclic monoterpene 5-bromo-5-bromomethyl-I-chlorovinyl-2,4-dichloro-methylcyclohexane (103) while the known compounds were identified as 4-bromo-5-bromomethyl-1chlorovinyl-2,5-dichloro-methylcyclohexane (35), 1,4,8-tribromo-3, 7 -dichloro-3,7-dimethyl-1,5-octadiene (94) and 8-bromo-1,3,4,7-tetrachloro-3,7-dimethyl-1,5-octadiene (96). The four methoxylated compounds (104-107) were presumably formed via a standard substitution reaction between the halogenated monoterpenes 96 and 101 and MeOH, which was used as a component in the extraction solvent. With over 100 000 natural products having been reported, it has become necessary to employ an efficient dereplication strategy to quickly identify known compounds. A simple Gas Chromatography-Mass Spectrometry (GC-MS) method for the efficient physicochemical screening, identification and dereplication of Plocamium metabolites was developed. In this study the crude extracts of P. corallorhiza, P. cornutum and P. maxillosum were screened by GC-MS and the retention times and mass spectral fragmentation patterns of compounds 94, 96, 99 - 107 were used to quickly identify known and new compounds in the crude extracts of P. cornutum and P. maxillosum. This data indicated that compounds 99, 100, 103 were present in both P. corallorhiza and P.cornutum, while compound 102 was found to be present in P. corallorhiza, P. cornutum and P. maxillosum. These studies also indicated that ecotypes and chemotypes are not a significant feature of P. corallorhiza and P. cornutum. Different species of Plocamium (namely: P. corallorhiza, P. cornutum, and P. maxillosum) have very different chemical profiles, and GC may therefore have appreciable taxonomic application in the identification of the different Plocamium spp. which are endemic to South Africa.
- Full Text:
- Date Issued: 2003
- Authors: Knott, Michael George
- Date: 2003
- Subjects: Marine algae -- South Africa Red algae -- South Africa Green algae -- South Africa Halimeda -- South Africa
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: vital:3820 , http://hdl.handle.net/10962/d1004920
- Description: The brine shrimp lethality assay was used as a preliminary tool to screen eighteen seaweeds collected from the South African coast. Of the seaweeds tested, the red algae Plocamium corallorhiza and Hypnea rosea, and the green alga Halimeda sp., showed the most potent activity. The chemical investigation of P. corallorhiza resulted in the isolation and structural elucidation of five previously undescribed secondary metabolites, along with three known compounds and four possible artifacts of the extraction process. Standard spectroscopic methods and comparison with known compounds were used to determine the structures of the new metabolites. The new compounds included the linear halogenated monoterpenes 4,8-dibromo-1, 1-dichloro-3,7-dimethyl-2,6-octadiene (99), 4,6-dibromo-l, 1-dichloro-3,7-dimethyl-2,7-octadiene (100), 4,8-dibromo-l, 1,7-trichloro-3,7-dimethyl-2,5-octadiene (101) and 3,4,6,7-tetrachloro-3,7-dimethyl-l-octene (102) and the cyclic monoterpene 5-bromo-5-bromomethyl-I-chlorovinyl-2,4-dichloro-methylcyclohexane (103) while the known compounds were identified as 4-bromo-5-bromomethyl-1chlorovinyl-2,5-dichloro-methylcyclohexane (35), 1,4,8-tribromo-3, 7 -dichloro-3,7-dimethyl-1,5-octadiene (94) and 8-bromo-1,3,4,7-tetrachloro-3,7-dimethyl-1,5-octadiene (96). The four methoxylated compounds (104-107) were presumably formed via a standard substitution reaction between the halogenated monoterpenes 96 and 101 and MeOH, which was used as a component in the extraction solvent. With over 100 000 natural products having been reported, it has become necessary to employ an efficient dereplication strategy to quickly identify known compounds. A simple Gas Chromatography-Mass Spectrometry (GC-MS) method for the efficient physicochemical screening, identification and dereplication of Plocamium metabolites was developed. In this study the crude extracts of P. corallorhiza, P. cornutum and P. maxillosum were screened by GC-MS and the retention times and mass spectral fragmentation patterns of compounds 94, 96, 99 - 107 were used to quickly identify known and new compounds in the crude extracts of P. cornutum and P. maxillosum. This data indicated that compounds 99, 100, 103 were present in both P. corallorhiza and P.cornutum, while compound 102 was found to be present in P. corallorhiza, P. cornutum and P. maxillosum. These studies also indicated that ecotypes and chemotypes are not a significant feature of P. corallorhiza and P. cornutum. Different species of Plocamium (namely: P. corallorhiza, P. cornutum, and P. maxillosum) have very different chemical profiles, and GC may therefore have appreciable taxonomic application in the identification of the different Plocamium spp. which are endemic to South Africa.
- Full Text:
- Date Issued: 2003
Jane Austen re-visited a feminist evaluation of the longevity and relevance of the Austen Oeuvre
- Authors: Kollmann, Elizabeth
- Date: 2003
- Subjects: Austen, Jane, 1775-1817 -- Criticism and interpretation , Feminist literary criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10994 , http://hdl.handle.net/10948/299 , Austen, Jane, 1775-1817 -- Criticism and interpretation , Feminist literary criticism
- Description: Although many might consider Jane Austen to be outdated and clichéd, her work retains an undying appeal. During the last decade the English-speaking world has experienced an Austen renaissance as it has been treated to a number of film and television adaptations of her work, including Pride and Prejudice, Emma, Mansfield Park and Sense and Sensibility. Film critics such as Bill De Lapp (1996) and Sherry Dean (1996) have commented on the phenomenal response these productions received and have been amazed by Austen’s ability to compete with current movie scripts. The reasons for viewers and readers enjoying and identifying with Austen’s fiction are numerous. Readers of varying persuasions have different agendas and hence different views and interpretations of Austen. This thesis follows a gynocritical approach and applies a feminist point of view when reading and discussing Austen. Austen’s novels - Pride and Prejudice, Mansfield Park, Emma, Northanger Abbey, Sense and Sensibility, and Persuasion – are re-read and reevaluated from a feminist perspective in order to call attention to Austen’s awareness of women’s second-class position in her society. Women’s experiences in Austen’s time are compared to women’s experiences in society today in order to illustrate, in some way, the tremendous progress the feminist movement has made. In addition, by examining what Austen reveals about the material reality of women in her time, it is possible to explore the legacy that modern women have inherited. Literary critics such as André Brink (1998), Claudia Johnson (1988), and Gilbert and Gubar (1979) believe Austen to create feminist awareness in her novels. There are critics, however, who do not view Austen as necessarily feminist in her writing. Nancy Armstrong writes in Desire and Domestic Fiction (1987) that Austen’s objective is not a critique of the Abstract iv old order but rather a redefinition of wealth and status. In Culture and Imperialism (1993) Edward Said implicates Austen in the rationale for imperial expansion, while Barbara Seeber argues in “The Schooling of Marianne Dashwood” (1999) that Austen’s texts should be understood as dialogic. Others, such as Patricia Beer (1974), believe Austen’s fiction primarily to be about marriage since all her novels end with matrimony. My own reading of Austen takes into consideration her social milieu and patriarchal inheritance. It argues that Austen writes within the framework of patriarchy (for example by marrying off her heroines) possibly because she is aware that in order to survive as a woman (writer) in a male-favouring world and in a publishing world dominated by men, her critique needs to be covert. If read from a feminist perspective, Austen’s fiction draws our attention to issues such as women’s (lack of) education, the effects of not being given access to knowledge, marriage as a patriarchal institution of entrapment, and women’s identity. Her fiction reveals the effects of educating women for a life of domesticity, and illustrates that such an education is biased, leaving women powerless and without any means of self-protection in a male-dominated world. Although contemporary women in the Western world mostly enjoy equal education opportunities to men, they suffer the consequences of a legacy which denied them access to a proper education. Feminist writers such as Flis Henwood (2000) show that contemporary women believe certain areas of expertise belong to men exclusively. Others such as Linda Nochlin (1994) reveal that because women did not have access to higher education for so many years, they failed to produce great women artists like Chaucer or Cézanne. Austen’s fiction also exposes the economic and social system (of which education constitutes a major part) for enforcing marriage and for enfeebling women. In addition, it illustrates some of the realities and pitfalls of marriage. While Austen only subtly refers to Abstract v women’s disempowerment within marriage, contemporary feminist scholars such as Germaine Greer (1999) and Arnot, Araújo, Deliyanni, and Ivinson (2000) explicitly warn women that marriage is a patriarchal institution of entrapment and that it often leaves women feeling unfulfilled. The issue of marriage as a patriarchal institution has been thought important and has been addressed by feminists because it contributes to women’s powerlessness. Feminist scholars today find it imperative to expose all forms of power in order to eradicate women’s subordination. bell hooks comments in Feminist Theory: From Margin to Center (2000) on the importance of revealing unfair power relations in order to eliminate oppression of any kind. Austen does not necessarily express the wish to eradicate forms of power or oppression in her novels. Yet, if we read her work from a feminist point of view, we are made aware of the social construction of power. From her fiction we can infer that male power is enshrined in the very structure of society, and this makes us aware of women’s lack of power in her time. Austen’s novels, however, are not merely novels of powerlessness but of empowerment. By creating rounded women characters and by giving them the power to judge, to refuse and to write, Austen challenges the stereotyped view of woman as either overpowering monster or weak and fragile angel. In addition, her novels seem to question women’s inherited identity and to suggest that qualities such as emotionality and mothering are not natural aspects of being a woman. Because she suggests ways in which women might empower themselves, albeit within patriarchal parameters, one could argue that she contributes, in a small way, to the transformation of existing power relations and to the eradication of women’s servile position in society.
- Full Text:
- Date Issued: 2003
- Authors: Kollmann, Elizabeth
- Date: 2003
- Subjects: Austen, Jane, 1775-1817 -- Criticism and interpretation , Feminist literary criticism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10994 , http://hdl.handle.net/10948/299 , Austen, Jane, 1775-1817 -- Criticism and interpretation , Feminist literary criticism
- Description: Although many might consider Jane Austen to be outdated and clichéd, her work retains an undying appeal. During the last decade the English-speaking world has experienced an Austen renaissance as it has been treated to a number of film and television adaptations of her work, including Pride and Prejudice, Emma, Mansfield Park and Sense and Sensibility. Film critics such as Bill De Lapp (1996) and Sherry Dean (1996) have commented on the phenomenal response these productions received and have been amazed by Austen’s ability to compete with current movie scripts. The reasons for viewers and readers enjoying and identifying with Austen’s fiction are numerous. Readers of varying persuasions have different agendas and hence different views and interpretations of Austen. This thesis follows a gynocritical approach and applies a feminist point of view when reading and discussing Austen. Austen’s novels - Pride and Prejudice, Mansfield Park, Emma, Northanger Abbey, Sense and Sensibility, and Persuasion – are re-read and reevaluated from a feminist perspective in order to call attention to Austen’s awareness of women’s second-class position in her society. Women’s experiences in Austen’s time are compared to women’s experiences in society today in order to illustrate, in some way, the tremendous progress the feminist movement has made. In addition, by examining what Austen reveals about the material reality of women in her time, it is possible to explore the legacy that modern women have inherited. Literary critics such as André Brink (1998), Claudia Johnson (1988), and Gilbert and Gubar (1979) believe Austen to create feminist awareness in her novels. There are critics, however, who do not view Austen as necessarily feminist in her writing. Nancy Armstrong writes in Desire and Domestic Fiction (1987) that Austen’s objective is not a critique of the Abstract iv old order but rather a redefinition of wealth and status. In Culture and Imperialism (1993) Edward Said implicates Austen in the rationale for imperial expansion, while Barbara Seeber argues in “The Schooling of Marianne Dashwood” (1999) that Austen’s texts should be understood as dialogic. Others, such as Patricia Beer (1974), believe Austen’s fiction primarily to be about marriage since all her novels end with matrimony. My own reading of Austen takes into consideration her social milieu and patriarchal inheritance. It argues that Austen writes within the framework of patriarchy (for example by marrying off her heroines) possibly because she is aware that in order to survive as a woman (writer) in a male-favouring world and in a publishing world dominated by men, her critique needs to be covert. If read from a feminist perspective, Austen’s fiction draws our attention to issues such as women’s (lack of) education, the effects of not being given access to knowledge, marriage as a patriarchal institution of entrapment, and women’s identity. Her fiction reveals the effects of educating women for a life of domesticity, and illustrates that such an education is biased, leaving women powerless and without any means of self-protection in a male-dominated world. Although contemporary women in the Western world mostly enjoy equal education opportunities to men, they suffer the consequences of a legacy which denied them access to a proper education. Feminist writers such as Flis Henwood (2000) show that contemporary women believe certain areas of expertise belong to men exclusively. Others such as Linda Nochlin (1994) reveal that because women did not have access to higher education for so many years, they failed to produce great women artists like Chaucer or Cézanne. Austen’s fiction also exposes the economic and social system (of which education constitutes a major part) for enforcing marriage and for enfeebling women. In addition, it illustrates some of the realities and pitfalls of marriage. While Austen only subtly refers to Abstract v women’s disempowerment within marriage, contemporary feminist scholars such as Germaine Greer (1999) and Arnot, Araújo, Deliyanni, and Ivinson (2000) explicitly warn women that marriage is a patriarchal institution of entrapment and that it often leaves women feeling unfulfilled. The issue of marriage as a patriarchal institution has been thought important and has been addressed by feminists because it contributes to women’s powerlessness. Feminist scholars today find it imperative to expose all forms of power in order to eradicate women’s subordination. bell hooks comments in Feminist Theory: From Margin to Center (2000) on the importance of revealing unfair power relations in order to eliminate oppression of any kind. Austen does not necessarily express the wish to eradicate forms of power or oppression in her novels. Yet, if we read her work from a feminist point of view, we are made aware of the social construction of power. From her fiction we can infer that male power is enshrined in the very structure of society, and this makes us aware of women’s lack of power in her time. Austen’s novels, however, are not merely novels of powerlessness but of empowerment. By creating rounded women characters and by giving them the power to judge, to refuse and to write, Austen challenges the stereotyped view of woman as either overpowering monster or weak and fragile angel. In addition, her novels seem to question women’s inherited identity and to suggest that qualities such as emotionality and mothering are not natural aspects of being a woman. Because she suggests ways in which women might empower themselves, albeit within patriarchal parameters, one could argue that she contributes, in a small way, to the transformation of existing power relations and to the eradication of women’s servile position in society.
- Full Text:
- Date Issued: 2003
Apollo, Dionysus, dialectical reason and critical cinema
- Authors: Konik, Adrian
- Date: 2003
- Subjects: Motion pictures and language , Philosophy in motion pictures , Dionysus (Greek deity) in literature , Apollo (Greek deity) in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10990 , http://hdl.handle.net/10948/295 , Motion pictures and language , Philosophy in motion pictures , Dionysus (Greek deity) in literature , Apollo (Greek deity) in literature
- Description: The contemporary era is dominated by an Apollonian visual language, i.e. the visual language of mainstream cinema and the mass media, and this study concerns the role that critical cinema, as Dionysian subverter, plays under such conditions. I argue that critical cinema should not be viewed as something completely ‘new’ but rather as a new, or at least the latest, manifestation of an older subversive ‘Dionysian’ voice that has made its presence felt since the dawn of the hegemony of an Apollonian disposition in Homeric epic. (I maintain that the history of western culture can be understood in terms of the persistent tension between Apollonian and Dionysian dispositions, and I use the distinction Derrida makes in Différance, between restricted and general economies, to distinguish between them, respectively.) I begin by considering the Dionysian echoes within Homer’s Iliad and then consider the way in which they became a ‘roar’ in the tragedies of Aeschylus. After Aeschylus a predominantly Apollonian voice asserted itself once again (to various degrees) through the work of Sophocles and Euripides. This was in keeping with the trend towards a more (Apollonian) restricted economy that is reflected in the writings of Homer’s literary successors, and which reached a crucial stage in Plato’s valorisation of ‘dialectics’, or what I term ‘dialecticis m’, which saw the birth of ‘dialectical language’. Through Plato dialecticism, or dialectical language, became instantiated as the ‘language’ of western philosophy and this predisposed western culture to develop along predominantly Apollonian lines. This continued from Plato, through the Middle Ages, until in the 17th century this Apollonian trend became manifest in the concept of the stable, integral, autonomous and self -transparent Cartesian ego, which is inextricably linked to dialectical language that promises certainty of ‘truth’ and maintains the possibility of representing the world in its entirety (as a system). In the contemporary ‘age of a world picture’, the hegemonic (Apollonian) visual language of mainstream cinema and the mass media propagates and perpetuates the belief in the possibility of representing the world in its entirety through the image, and insofar as it caters to audiences’ needs for stability and certainty (of ‘truth’) through providing such ‘complete’ representations, shapes their subjectivity along the lines of the Cartesian ego. According to Baudrillard, in contemporary society and culture the hyperreal realm of visual language has become far more significant for individuals than their immediate, empirical experiences, and that, as a result, they are far less predisposed to discussion and reflection and far more prone to passive ‘watching’. Also, Adorno maintains that it is impossible to have a form of critical cinema because of the way in which features inherent to cinema predispose it towards being an ideological apparatus. However, if both Baudrillard and Adorno are correct then the future appears increasingly bleak as it involves nothing other than the continuation and propagation of the hegemony of the visual language of mainstream cinema and the mass media, with no possibility for critical resistance. I argue instead that critical cinema is possible because the move towards a more restricted economy, motivated by an Apollonian disposition, did not develop from Homer to the contemporary era without meeting Dionysian resistance. I trace the presence of a subversive Dionysian voice through Homer’s Iliad, through Aeschylus’ Prometheus Bound, and through Plato’s Dialogues, where it echoes in the sentiments of some of Plato’s interlocutors, such as Callicles. In addition, I maintain that a ‘Dionysian’ voice resonates through both Nietzsche’s and Heidegger’s respective criticisms of ‘dialectical language’ and the ‘validity’ of the Cartesian ego. I argue that critical cinema, particularly Aronofsky’s postmodern critical cinema, parallels their similar epistemological and ontological perspectives in the way in which it engages with the (Apollonian) visual language of mainstream cinema and the mass media, and thereby, potentially, facilitates a more porous and protean subjectivity.
- Full Text:
- Date Issued: 2003
- Authors: Konik, Adrian
- Date: 2003
- Subjects: Motion pictures and language , Philosophy in motion pictures , Dionysus (Greek deity) in literature , Apollo (Greek deity) in literature
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10990 , http://hdl.handle.net/10948/295 , Motion pictures and language , Philosophy in motion pictures , Dionysus (Greek deity) in literature , Apollo (Greek deity) in literature
- Description: The contemporary era is dominated by an Apollonian visual language, i.e. the visual language of mainstream cinema and the mass media, and this study concerns the role that critical cinema, as Dionysian subverter, plays under such conditions. I argue that critical cinema should not be viewed as something completely ‘new’ but rather as a new, or at least the latest, manifestation of an older subversive ‘Dionysian’ voice that has made its presence felt since the dawn of the hegemony of an Apollonian disposition in Homeric epic. (I maintain that the history of western culture can be understood in terms of the persistent tension between Apollonian and Dionysian dispositions, and I use the distinction Derrida makes in Différance, between restricted and general economies, to distinguish between them, respectively.) I begin by considering the Dionysian echoes within Homer’s Iliad and then consider the way in which they became a ‘roar’ in the tragedies of Aeschylus. After Aeschylus a predominantly Apollonian voice asserted itself once again (to various degrees) through the work of Sophocles and Euripides. This was in keeping with the trend towards a more (Apollonian) restricted economy that is reflected in the writings of Homer’s literary successors, and which reached a crucial stage in Plato’s valorisation of ‘dialectics’, or what I term ‘dialecticis m’, which saw the birth of ‘dialectical language’. Through Plato dialecticism, or dialectical language, became instantiated as the ‘language’ of western philosophy and this predisposed western culture to develop along predominantly Apollonian lines. This continued from Plato, through the Middle Ages, until in the 17th century this Apollonian trend became manifest in the concept of the stable, integral, autonomous and self -transparent Cartesian ego, which is inextricably linked to dialectical language that promises certainty of ‘truth’ and maintains the possibility of representing the world in its entirety (as a system). In the contemporary ‘age of a world picture’, the hegemonic (Apollonian) visual language of mainstream cinema and the mass media propagates and perpetuates the belief in the possibility of representing the world in its entirety through the image, and insofar as it caters to audiences’ needs for stability and certainty (of ‘truth’) through providing such ‘complete’ representations, shapes their subjectivity along the lines of the Cartesian ego. According to Baudrillard, in contemporary society and culture the hyperreal realm of visual language has become far more significant for individuals than their immediate, empirical experiences, and that, as a result, they are far less predisposed to discussion and reflection and far more prone to passive ‘watching’. Also, Adorno maintains that it is impossible to have a form of critical cinema because of the way in which features inherent to cinema predispose it towards being an ideological apparatus. However, if both Baudrillard and Adorno are correct then the future appears increasingly bleak as it involves nothing other than the continuation and propagation of the hegemony of the visual language of mainstream cinema and the mass media, with no possibility for critical resistance. I argue instead that critical cinema is possible because the move towards a more restricted economy, motivated by an Apollonian disposition, did not develop from Homer to the contemporary era without meeting Dionysian resistance. I trace the presence of a subversive Dionysian voice through Homer’s Iliad, through Aeschylus’ Prometheus Bound, and through Plato’s Dialogues, where it echoes in the sentiments of some of Plato’s interlocutors, such as Callicles. In addition, I maintain that a ‘Dionysian’ voice resonates through both Nietzsche’s and Heidegger’s respective criticisms of ‘dialectical language’ and the ‘validity’ of the Cartesian ego. I argue that critical cinema, particularly Aronofsky’s postmodern critical cinema, parallels their similar epistemological and ontological perspectives in the way in which it engages with the (Apollonian) visual language of mainstream cinema and the mass media, and thereby, potentially, facilitates a more porous and protean subjectivity.
- Full Text:
- Date Issued: 2003
A generic simulation of energy consumption of automobile air conditioning systems
- Authors: Konz, Martin
- Date: 2003
- Subjects: Automobiles -- Air conditioning
- Language: English
- Type: Thesis , Masters , MTech (Engineering)
- Identifier: vital:10822 , http://hdl.handle.net/10948/129 , Automobiles -- Air conditioning
- Description: The air conditioning system in a car is, in addition to the heating system, installed to increase the comfort in the passenger compartment. Comfort is not the only reason for automotive air conditioning systems, as road safety also improves with the comfort of the driver, as a pleasant environment reduces driver fatigue. The rising environmental problems and, hence, resulting stringent legislation are forcing the automobile industry to develop cars with ever decreasing fuel consumptions. The question of better fuel consumption and energy utilisation does not stop with the engine and aerodynamics, but is required of the air-conditioning system as well. Thus, incessantly innovative technologies are developed to decrease the energy required by the air-conditioning systems. The interaction of the refrigerant cycle components and the rapidly changing operating conditions of the car (speed, revolutions per minute, etc.) places extensive demands on the control system. In addition, the air-conditioning system is also designed for high ambient temperatures (cool down), but is mostly used in fairly moderate conditions. This operation allows for energy saving control strategies such as externally controlled compressors, blower motor control, etc. The experimental comparison of different air-conditioning systems, components or control strategies is very time consuming and extensive, and the use of an air-conditioned wind tunnel is inevitable when experiments need to be done with reproducible ambient conditions.This, combined with the high costs of installation and operation of a wind tunnel is a major problem. Furthermore, the effect of component or control strategy enhancements should be available as soon as possible in the early stages of design. The above considerations have prompted the rapid development of new powerful simulation tools, but in most cases the simulation tools are focused on one specific component or problem only. A more holistic approach would be to combine the calculations of two or more programs. This implies the adaptation of the model to more programs which leads to a lack of transparency. Obviously, the entire development work cannot be done entirely by simulation, especially in the later phases of the development where it would still be necessary to build prototypes to evaluate the done work experimentally. However, in the early stages of development, it would be advantagous to work without expensive prototypes.
- Full Text:
- Date Issued: 2003
- Authors: Konz, Martin
- Date: 2003
- Subjects: Automobiles -- Air conditioning
- Language: English
- Type: Thesis , Masters , MTech (Engineering)
- Identifier: vital:10822 , http://hdl.handle.net/10948/129 , Automobiles -- Air conditioning
- Description: The air conditioning system in a car is, in addition to the heating system, installed to increase the comfort in the passenger compartment. Comfort is not the only reason for automotive air conditioning systems, as road safety also improves with the comfort of the driver, as a pleasant environment reduces driver fatigue. The rising environmental problems and, hence, resulting stringent legislation are forcing the automobile industry to develop cars with ever decreasing fuel consumptions. The question of better fuel consumption and energy utilisation does not stop with the engine and aerodynamics, but is required of the air-conditioning system as well. Thus, incessantly innovative technologies are developed to decrease the energy required by the air-conditioning systems. The interaction of the refrigerant cycle components and the rapidly changing operating conditions of the car (speed, revolutions per minute, etc.) places extensive demands on the control system. In addition, the air-conditioning system is also designed for high ambient temperatures (cool down), but is mostly used in fairly moderate conditions. This operation allows for energy saving control strategies such as externally controlled compressors, blower motor control, etc. The experimental comparison of different air-conditioning systems, components or control strategies is very time consuming and extensive, and the use of an air-conditioned wind tunnel is inevitable when experiments need to be done with reproducible ambient conditions.This, combined with the high costs of installation and operation of a wind tunnel is a major problem. Furthermore, the effect of component or control strategy enhancements should be available as soon as possible in the early stages of design. The above considerations have prompted the rapid development of new powerful simulation tools, but in most cases the simulation tools are focused on one specific component or problem only. A more holistic approach would be to combine the calculations of two or more programs. This implies the adaptation of the model to more programs which leads to a lack of transparency. Obviously, the entire development work cannot be done entirely by simulation, especially in the later phases of the development where it would still be necessary to build prototypes to evaluate the done work experimentally. However, in the early stages of development, it would be advantagous to work without expensive prototypes.
- Full Text:
- Date Issued: 2003
The individual and the social order in Mill and Hegel : seeking common principles in liberal and communitarian ancestry
- Authors: Koseff, Justin Adam
- Date: 2003
- Subjects: Hegel, Georg Wilhelm Friedrich, 1770-1831 , Mill, John Stuart, 1806-1873 , Liberalism , Communitarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2843 , http://hdl.handle.net/10962/d1005624 , Hegel, Georg Wilhelm Friedrich, 1770-1831 , Mill, John Stuart, 1806-1873 , Liberalism , Communitarianism
- Description: This thesis seeks to establish a significant commonality and compatibility between the principles underpinning the political and social philosophies of GWF Hegel and John Stuart Mill. The role of the individual and the social order in both their theories is discussed and assessed separately and in turn in reference to their respective seminal works on the proper structure, principles and function of modern political infrastructure. Through an interpretation of the fundamental tenets and goals of their theories of the social order I argue for a coherent modern reconstruction of their doctrines, within which I locate parallels and contrasts as they apply. Both theorists as ultimately put forward similar arguments for freedom as an intersubjectively·developed capacity, the ideal social order as rational framework for the management of ethical and political engagement, linked to a social holism that ties individual and social progress inextricably. A respect for individual particularity of perspective and practice is integral both of their social frameworks, but that such a space must be harmonised within a rational political community worthy of individual obligation. Finally their social and political theories can be understood as complementary, each providing insights which the other lacks. Mill suffers from an insufficient regard for the social basis of identity and interconnected nature of the modern institutional framework, while Hegel displays an insufficient regard for Mill's caveats concerning the repressive potential of institutional structures and the dangers of overly empowered bureaucracies. In conclusion key elements of the two theorists' projects stand as separate but not in any way fundamentally opposed to each other. This points to the possibility of a via media between a politics of individualism and a politics of community, suggesting strong potential for reconciliation between liberal and communitarian perspectives.
- Full Text:
- Date Issued: 2003
- Authors: Koseff, Justin Adam
- Date: 2003
- Subjects: Hegel, Georg Wilhelm Friedrich, 1770-1831 , Mill, John Stuart, 1806-1873 , Liberalism , Communitarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2843 , http://hdl.handle.net/10962/d1005624 , Hegel, Georg Wilhelm Friedrich, 1770-1831 , Mill, John Stuart, 1806-1873 , Liberalism , Communitarianism
- Description: This thesis seeks to establish a significant commonality and compatibility between the principles underpinning the political and social philosophies of GWF Hegel and John Stuart Mill. The role of the individual and the social order in both their theories is discussed and assessed separately and in turn in reference to their respective seminal works on the proper structure, principles and function of modern political infrastructure. Through an interpretation of the fundamental tenets and goals of their theories of the social order I argue for a coherent modern reconstruction of their doctrines, within which I locate parallels and contrasts as they apply. Both theorists as ultimately put forward similar arguments for freedom as an intersubjectively·developed capacity, the ideal social order as rational framework for the management of ethical and political engagement, linked to a social holism that ties individual and social progress inextricably. A respect for individual particularity of perspective and practice is integral both of their social frameworks, but that such a space must be harmonised within a rational political community worthy of individual obligation. Finally their social and political theories can be understood as complementary, each providing insights which the other lacks. Mill suffers from an insufficient regard for the social basis of identity and interconnected nature of the modern institutional framework, while Hegel displays an insufficient regard for Mill's caveats concerning the repressive potential of institutional structures and the dangers of overly empowered bureaucracies. In conclusion key elements of the two theorists' projects stand as separate but not in any way fundamentally opposed to each other. This points to the possibility of a via media between a politics of individualism and a politics of community, suggesting strong potential for reconciliation between liberal and communitarian perspectives.
- Full Text:
- Date Issued: 2003
Provocation as a defence in English and South African criminal law
- Authors: Krause, Samantha
- Date: 2003
- Subjects: Provocation (Criminal law) -- South Africa , Provocation (Criminal law) -- Great Britain
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11044 , http://hdl.handle.net/10948/310 , Provocation (Criminal law) -- South Africa , Provocation (Criminal law) -- Great Britain
- Description: In the past 20 years the defence of provocation has shifted from the periphery of South African law to a fully developed defence available to those who kill when provoked. Not only is the defence available to the provoked, but it has been extended to those who kill when subjected to emotional stress. However, the defence is mirred in controversy and bad decisions. Not only has the precise nature of the defence not been clarified, but this lack of clarity has been exacerbated by confusing decisions of our courts. This confusion is partly a result of the development of the defence of incapacity, particularly its extension to cases involving provocation and mental stress, and partly a result of its application in practice. Three major problems have plagued the provocation defence. Firstly, the courts have confused the defence of sane automatism with that of non-pathological incapacity. Secondly, there has been an implied use of an objective test in determining criminal incapacity where the enquiry has clearly been a subjective one. Thirdly, it has been held that the problem may not so much be the subjective aspect of provocation, but rather its application. The real problem seems to lie in the theoretical confusion as to the precise meaning of lack of “selfcontrol”. Lastly, on occasion the courts have failed to distinguish lack of capacity from diminished responsibility. Thus, in order to gain clarity concerning this “grey” area of the law these problems have created, it is necessary for South African law to consult more authoritative sources to receive guidance for the problems identified. One of those sources that has been consulted is that of English law. English law, however, deals with the defence of provocation in a different manner. Raising a defence of provocation here does not result in an acquittal but rather in a reduction of the charge to manslaughter. However, the English law on provocation is also 7 plagued by various problems. Firstly, there is the issue of cumulative provocation. Generally, there is little difficulty in cases where there is no “immediate trigger”. Secondly, the fundamental flaw with the current test of the reasonable man is that the courts have had to swing between the two aims of taking a compassionate view of human frailty while endeavoring to maintain an objective standard of the reasonable man. Lastly, it can be said that the problem with the proportionality requirement is that it makes the provocation defence dependant upon the assessment of the accused’s conduct after he or she lost his or her selfcontrol rather than on his or her giving way to passion and losing control in the first place. It is clear that from the problems identified in both South African law and English law concerning the defence of provocation the courts in each jurisdiction will have to pay careful attentio n to the problems highlighted and apply the law in such a way so as to ensure clarity and legal certainty.
- Full Text:
- Date Issued: 2003
- Authors: Krause, Samantha
- Date: 2003
- Subjects: Provocation (Criminal law) -- South Africa , Provocation (Criminal law) -- Great Britain
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11044 , http://hdl.handle.net/10948/310 , Provocation (Criminal law) -- South Africa , Provocation (Criminal law) -- Great Britain
- Description: In the past 20 years the defence of provocation has shifted from the periphery of South African law to a fully developed defence available to those who kill when provoked. Not only is the defence available to the provoked, but it has been extended to those who kill when subjected to emotional stress. However, the defence is mirred in controversy and bad decisions. Not only has the precise nature of the defence not been clarified, but this lack of clarity has been exacerbated by confusing decisions of our courts. This confusion is partly a result of the development of the defence of incapacity, particularly its extension to cases involving provocation and mental stress, and partly a result of its application in practice. Three major problems have plagued the provocation defence. Firstly, the courts have confused the defence of sane automatism with that of non-pathological incapacity. Secondly, there has been an implied use of an objective test in determining criminal incapacity where the enquiry has clearly been a subjective one. Thirdly, it has been held that the problem may not so much be the subjective aspect of provocation, but rather its application. The real problem seems to lie in the theoretical confusion as to the precise meaning of lack of “selfcontrol”. Lastly, on occasion the courts have failed to distinguish lack of capacity from diminished responsibility. Thus, in order to gain clarity concerning this “grey” area of the law these problems have created, it is necessary for South African law to consult more authoritative sources to receive guidance for the problems identified. One of those sources that has been consulted is that of English law. English law, however, deals with the defence of provocation in a different manner. Raising a defence of provocation here does not result in an acquittal but rather in a reduction of the charge to manslaughter. However, the English law on provocation is also 7 plagued by various problems. Firstly, there is the issue of cumulative provocation. Generally, there is little difficulty in cases where there is no “immediate trigger”. Secondly, the fundamental flaw with the current test of the reasonable man is that the courts have had to swing between the two aims of taking a compassionate view of human frailty while endeavoring to maintain an objective standard of the reasonable man. Lastly, it can be said that the problem with the proportionality requirement is that it makes the provocation defence dependant upon the assessment of the accused’s conduct after he or she lost his or her selfcontrol rather than on his or her giving way to passion and losing control in the first place. It is clear that from the problems identified in both South African law and English law concerning the defence of provocation the courts in each jurisdiction will have to pay careful attentio n to the problems highlighted and apply the law in such a way so as to ensure clarity and legal certainty.
- Full Text:
- Date Issued: 2003
Intelligent monitoring and control system for a friction stir welding process
- Authors: Kruger, Grant
- Date: 2003
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10823 , http://hdl.handle.net/10948/273 , Friction welding
- Description: A Friction Stir Welding machine is proposed and built to allow future research into the process and to provide a framework from which the application of intelligent manufacturing to industrial processes can be investigated. Initially a literature survey was conducted upon which the design of the machine could be based. The conversion of a conventional milling machine into a Friction Stir Welding machine by applying modern monitoring and control systems is then presented. Complete digital control was used to drive actuators and monitor sensors. A wireless chuck mounted monitoring system was implemented, enabling forces, torques, temperature and speed of the tool to be obtained directly from the process. Software based on a hierarchical Open Systems Architectural design, incorporating modularity, interoperability, portability and extensibility is implemented. This experimental setup is used to analyze the Friction Stir Welding process by performing data analysis using statistical methods. Three independent variables (weld speed, spindle speed and plunge depth) were varied and the independent variables (forces, torques, power, temperature, speed, etc) recorded using the implemented software. The statistical analysis includes the analysis of variants, regression analysis and the creation of surface plots. Using these results, certain linguistic rules for process control are proposed. An intelligent controller is designed and discussed, using the derived rules to improve and optimize certain aspects of the process encountered during the experimental phase of the research.
- Full Text:
- Date Issued: 2003
- Authors: Kruger, Grant
- Date: 2003
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10823 , http://hdl.handle.net/10948/273 , Friction welding
- Description: A Friction Stir Welding machine is proposed and built to allow future research into the process and to provide a framework from which the application of intelligent manufacturing to industrial processes can be investigated. Initially a literature survey was conducted upon which the design of the machine could be based. The conversion of a conventional milling machine into a Friction Stir Welding machine by applying modern monitoring and control systems is then presented. Complete digital control was used to drive actuators and monitor sensors. A wireless chuck mounted monitoring system was implemented, enabling forces, torques, temperature and speed of the tool to be obtained directly from the process. Software based on a hierarchical Open Systems Architectural design, incorporating modularity, interoperability, portability and extensibility is implemented. This experimental setup is used to analyze the Friction Stir Welding process by performing data analysis using statistical methods. Three independent variables (weld speed, spindle speed and plunge depth) were varied and the independent variables (forces, torques, power, temperature, speed, etc) recorded using the implemented software. The statistical analysis includes the analysis of variants, regression analysis and the creation of surface plots. Using these results, certain linguistic rules for process control are proposed. An intelligent controller is designed and discussed, using the derived rules to improve and optimize certain aspects of the process encountered during the experimental phase of the research.
- Full Text:
- Date Issued: 2003
Weblogging is ‘We Media’:
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159134 , vital:40270 , https://hdl.handle.net/10520/EJC146248
- Description: "Blogging technology has begun to deliver on some of the wild promises about the Internet that were heard in the 1990s," wrote Matt Welch in the September/October issue of Columbia Journalism Review, America's leading media monitor published by the Graduate School of Journalism at Columbia University.
- Full Text:
- Date Issued: 2003
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159134 , vital:40270 , https://hdl.handle.net/10520/EJC146248
- Description: "Blogging technology has begun to deliver on some of the wild promises about the Internet that were heard in the 1990s," wrote Matt Welch in the September/October issue of Columbia Journalism Review, America's leading media monitor published by the Graduate School of Journalism at Columbia University.
- Full Text:
- Date Issued: 2003
Pipes, poles and people:
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159153 , vital:40273 , https://hdl.handle.net/10520/EJC146268
- Description: Tina James, a South African ICT consultant, tells the story of Minnie Barendse Kruger who had been struggling to get a Khoisan Cultural Village going in the Eastern Cape. Kruger set up a restaurant where traditional food is prepared, and the Barendse Griquas Trust stepped in and helped set up a multi-purpose Community Centre.
- Full Text:
- Date Issued: 2003
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159153 , vital:40273 , https://hdl.handle.net/10520/EJC146268
- Description: Tina James, a South African ICT consultant, tells the story of Minnie Barendse Kruger who had been struggling to get a Khoisan Cultural Village going in the Eastern Cape. Kruger set up a restaurant where traditional food is prepared, and the Barendse Griquas Trust stepped in and helped set up a multi-purpose Community Centre.
- Full Text:
- Date Issued: 2003
The stories in the details:
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159177 , vital:40274 , https://hdl.handle.net/10520/EJC146272
- Description: A famous journalism adage is that "the story is in the details". For the world Information Society, those details might be in the mind-blowing technological advances in recent years and the dizzying alternative news sources; and in the increased novelty in story telling.
- Full Text:
- Date Issued: 2003
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159177 , vital:40274 , https://hdl.handle.net/10520/EJC146272
- Description: A famous journalism adage is that "the story is in the details". For the world Information Society, those details might be in the mind-blowing technological advances in recent years and the dizzying alternative news sources; and in the increased novelty in story telling.
- Full Text:
- Date Issued: 2003
The World Internet Project:
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159116 , vital:40269 , https://hdl.handle.net/10520/EJC146247
- Description: Here's a disturbing detail from the United Nations Development Programme (UNDP): only 1 in 118 Africans has access to the Internet. This ratio is actually skewed, partly because it averages out statistics in big countries (Egypt, South Africa) and the big cities (Johannesburg, Cairo, Cape Town, Lagos) with their poorer country cousins (Central African Republic, Mauritania).
- Full Text:
- Date Issued: 2003
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159116 , vital:40269 , https://hdl.handle.net/10520/EJC146247
- Description: Here's a disturbing detail from the United Nations Development Programme (UNDP): only 1 in 118 Africans has access to the Internet. This ratio is actually skewed, partly because it averages out statistics in big countries (Egypt, South Africa) and the big cities (Johannesburg, Cairo, Cape Town, Lagos) with their poorer country cousins (Central African Republic, Mauritania).
- Full Text:
- Date Issued: 2003
The OSS promise:
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159138 , vital:40271 , https://hdl.handle.net/10520/EJC146251
- Description: For Africa the attraction of open source software (OSS), is obvious. But for once, Internet intellectuals are not simply sounding off to annoy the rich north.
- Full Text:
- Date Issued: 2003
- Authors: Kyazze, Sim
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159138 , vital:40271 , https://hdl.handle.net/10520/EJC146251
- Description: For Africa the attraction of open source software (OSS), is obvious. But for once, Internet intellectuals are not simply sounding off to annoy the rich north.
- Full Text:
- Date Issued: 2003
Metal interactions with neural substrates and their role in neurodegeneration
- Authors: Lack, Barbara Anne
- Date: 2003
- Subjects: Nervous system -- Degeneration Neurotoxicology Chemical reactions Metals -- Physiological effect Melatonin -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4391 , http://hdl.handle.net/10962/d1005709
- Description: "Life" may be characterized as a controlled stationary flow equilibrium, maintained by energy consuming chemical reactions. The physiological functioning of these life systems include at least 28 of the elements isolated on the periodic table thus far, most of which are metals. However, as with Paracelsus Principle: "The dose makes the poison", there exists a definite link between metal levels, essential and toxic, and the onset of neurodegenerative diseases. The economic costs of brain dysfunction are enormous, but this pales in comparison to the staggering emotional toll on the victims themselves and their families. In an attempt to improve the understanding of the causes of neurodegeneration, this study focuses on one potential aspect: the possible link between metals and neurotransmitter homeostasis utilising a variety of electronanalytical techniques. Adsorptive cathodic stripping voltammetry was employed to investigate the binding affinities and complex formation of melatonin and its precursor serotonin with calcium, potassium, sodium, lithium and aluminium. The results showed that all the metals studied formed complexes with both pineal indoleamines. However, the stability and affmity of the ligands toward the various metals varied greatly. The study suggests a further role for melatonin, that of metalloregulator and possible metal detoxifier in the brain, the in vivo studies which followed will further substantiate this notion. This research additionally focused on the cholinergic system, in particular acetylcholine complex formation studies with mercury, lead, cadmium, copper and zinc using the adsorptive cathodic stripping voltammetry method. The formation and characterisation of a solid mercury-acetylcholine complex lent further strength to the in situ electrochemical complex formation observed. The results showed the preference of acetylcholine for environmentally toxic heavy metals (such as Cd²⁺) over those divalent cations that occur naturally in the body. The possible metalloregulatory role melatonin played in the three brain regIOns: cerebellum, cortex and corpus striatum of male Wistar rats was studied as an in vivo extension of the earlier in vitro studies. Anodic stripping voltammetry was employed to detect metal levels present. The results showed that daily injections of melatonin was responsible for significantly decreasing copper(I), cadmium(II) and lead(II) levels in various regions of the rat brain of those animals that had undergone a pinealectomy in comparison to the saline injected group having undergone the same treatment. Histological and electrochemical stripping techniques were applied to investigate the implications of high A1³⁺ levels in the brain regions, particularly the hippocampus. Melatonin showed signs of promise in indirect symptom alleviation and by significantly decreasing A1³⁺ levels in rats that had been dosed with melatonin prior to A1³⁺ treatments in comparison with the control groups. Finally a preliminary study outlining a method for the production of a calcium selective microelectrode was undertaken. Further work is still needed to optimise the microelectrode production as well as its possible applications. However, whilst the overall conclusions of this entire multidisciplinary study may indeed only be in effect one piece of a very large puzzle on neurodegenerative diseases, this piece will no doubt serve as a building block for further ideas and work in this field.
- Full Text:
- Date Issued: 2003
- Authors: Lack, Barbara Anne
- Date: 2003
- Subjects: Nervous system -- Degeneration Neurotoxicology Chemical reactions Metals -- Physiological effect Melatonin -- Physiological effect
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4391 , http://hdl.handle.net/10962/d1005709
- Description: "Life" may be characterized as a controlled stationary flow equilibrium, maintained by energy consuming chemical reactions. The physiological functioning of these life systems include at least 28 of the elements isolated on the periodic table thus far, most of which are metals. However, as with Paracelsus Principle: "The dose makes the poison", there exists a definite link between metal levels, essential and toxic, and the onset of neurodegenerative diseases. The economic costs of brain dysfunction are enormous, but this pales in comparison to the staggering emotional toll on the victims themselves and their families. In an attempt to improve the understanding of the causes of neurodegeneration, this study focuses on one potential aspect: the possible link between metals and neurotransmitter homeostasis utilising a variety of electronanalytical techniques. Adsorptive cathodic stripping voltammetry was employed to investigate the binding affinities and complex formation of melatonin and its precursor serotonin with calcium, potassium, sodium, lithium and aluminium. The results showed that all the metals studied formed complexes with both pineal indoleamines. However, the stability and affmity of the ligands toward the various metals varied greatly. The study suggests a further role for melatonin, that of metalloregulator and possible metal detoxifier in the brain, the in vivo studies which followed will further substantiate this notion. This research additionally focused on the cholinergic system, in particular acetylcholine complex formation studies with mercury, lead, cadmium, copper and zinc using the adsorptive cathodic stripping voltammetry method. The formation and characterisation of a solid mercury-acetylcholine complex lent further strength to the in situ electrochemical complex formation observed. The results showed the preference of acetylcholine for environmentally toxic heavy metals (such as Cd²⁺) over those divalent cations that occur naturally in the body. The possible metalloregulatory role melatonin played in the three brain regIOns: cerebellum, cortex and corpus striatum of male Wistar rats was studied as an in vivo extension of the earlier in vitro studies. Anodic stripping voltammetry was employed to detect metal levels present. The results showed that daily injections of melatonin was responsible for significantly decreasing copper(I), cadmium(II) and lead(II) levels in various regions of the rat brain of those animals that had undergone a pinealectomy in comparison to the saline injected group having undergone the same treatment. Histological and electrochemical stripping techniques were applied to investigate the implications of high A1³⁺ levels in the brain regions, particularly the hippocampus. Melatonin showed signs of promise in indirect symptom alleviation and by significantly decreasing A1³⁺ levels in rats that had been dosed with melatonin prior to A1³⁺ treatments in comparison with the control groups. Finally a preliminary study outlining a method for the production of a calcium selective microelectrode was undertaken. Further work is still needed to optimise the microelectrode production as well as its possible applications. However, whilst the overall conclusions of this entire multidisciplinary study may indeed only be in effect one piece of a very large puzzle on neurodegenerative diseases, this piece will no doubt serve as a building block for further ideas and work in this field.
- Full Text:
- Date Issued: 2003
Cimetidine as a free radical scavenger
- Authors: Lambat, Zaynab Yusuf
- Date: 2003
- Subjects: Cimetidine , Cimetidine -- Physiological effect , Cimetidine -- Therapeutic use , Alzheimer's disease -- Treatment , Cancer -- Treatment , Free radicals (Chemistry) -- Physiological effect
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3766 , http://hdl.handle.net/10962/d1003244 , Cimetidine , Cimetidine -- Physiological effect , Cimetidine -- Therapeutic use , Alzheimer's disease -- Treatment , Cancer -- Treatment , Free radicals (Chemistry) -- Physiological effect
- Description: The present study was undertaken to determine the effects and possible mechanism of action of cimetidine in cancer and Alzheimer’s disease (AD). Throughout this study emphasis is placed on free radical levels since the magnitude of the relationship between diseases and the levels of free radicals vary from one disease to another. Studies were carried out to examine the effect of cimetidine on free radical levels using superoxide formation and lipid peroxidation as indicators of free radical levels. The experiments revealed that addition of cimetidine, especially in high concentrations (0.5 and 1.0 x10-6 M) significantly inhibited WHCO6 cancer cell growth rather than cancer cell growth, as no normal control was available. Free radical formation as well as hydroxyl radical formation were reduced in the deoxyribose assay. In addition, cimetidine exhibits properties of binding to metals such as copper and iron. To maintain consistency in the experiments, a WHCO6 (Wits Human Carcinoma of the Oesophagus) cell line was used to investigate the effect of cimetidine in cancer. Neurodegeneration was induced in the rat brain using neurotoxins such as cyanide to investigate the relationship between cimetidine in AD. A decrease in cancer cell growth was accompanied by a concomitant decrease in the levels of free radicals and lipid peroxidation, suggesting that the growth-inhibitory effects of cimetidine on WHCO6 cancer cells in vitro may be due to free radical scavenging properties. This proposal was further strengthened by determination of free radical levels in the rat brain. After treatment with neurotoxins to induce neurodegeneration, the levels of free radicals in the rat brain suggest that addition of cimetidine reduces free radical levels in the rat brain in a dosedependent manner. Further experiments were done in an attempt to uncover the underlying mechanism by which cimetidine exhibits free radical scavenging properties. Metal binding studies were done using electrochemical, HPLC and UV/Vis studies. The results show that cimetidine binds iron and copper. These metals have been implicated in free radical production via the Fenton reaction. By binding with cimetidine the metals become unavailable to produce free radicals and hence cimetidine indirectly reduces the formation of free radicals. The final experiment was the determination of cimetidine as a hydroxyl radical scavenger in the deoxyribose assay. Cimetidine was shown to act as a potent hydroxyl radical scavenger, thereby confirming its activity as a free radical scavenger. In addition, cimetidine protects against damage to the deoxyribose sugar, a component of DNA. Whilst there are many theories that explain the therapeutic role of cimetidine in degenerative disease, the actual mechanism of the role of cimetidine is emphasized as a free radical scavenger. Regardless of the mechanism of action, cimetidine does inhibit tumour growth according to this study and also reduce free radical levels in neurodegeneration, which suggests a role for cimetidine as a possible additive in treatment of patients with such disease states. These findings have important clinical implications, and needs to be investigated further.
- Full Text:
- Date Issued: 2003
- Authors: Lambat, Zaynab Yusuf
- Date: 2003
- Subjects: Cimetidine , Cimetidine -- Physiological effect , Cimetidine -- Therapeutic use , Alzheimer's disease -- Treatment , Cancer -- Treatment , Free radicals (Chemistry) -- Physiological effect
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3766 , http://hdl.handle.net/10962/d1003244 , Cimetidine , Cimetidine -- Physiological effect , Cimetidine -- Therapeutic use , Alzheimer's disease -- Treatment , Cancer -- Treatment , Free radicals (Chemistry) -- Physiological effect
- Description: The present study was undertaken to determine the effects and possible mechanism of action of cimetidine in cancer and Alzheimer’s disease (AD). Throughout this study emphasis is placed on free radical levels since the magnitude of the relationship between diseases and the levels of free radicals vary from one disease to another. Studies were carried out to examine the effect of cimetidine on free radical levels using superoxide formation and lipid peroxidation as indicators of free radical levels. The experiments revealed that addition of cimetidine, especially in high concentrations (0.5 and 1.0 x10-6 M) significantly inhibited WHCO6 cancer cell growth rather than cancer cell growth, as no normal control was available. Free radical formation as well as hydroxyl radical formation were reduced in the deoxyribose assay. In addition, cimetidine exhibits properties of binding to metals such as copper and iron. To maintain consistency in the experiments, a WHCO6 (Wits Human Carcinoma of the Oesophagus) cell line was used to investigate the effect of cimetidine in cancer. Neurodegeneration was induced in the rat brain using neurotoxins such as cyanide to investigate the relationship between cimetidine in AD. A decrease in cancer cell growth was accompanied by a concomitant decrease in the levels of free radicals and lipid peroxidation, suggesting that the growth-inhibitory effects of cimetidine on WHCO6 cancer cells in vitro may be due to free radical scavenging properties. This proposal was further strengthened by determination of free radical levels in the rat brain. After treatment with neurotoxins to induce neurodegeneration, the levels of free radicals in the rat brain suggest that addition of cimetidine reduces free radical levels in the rat brain in a dosedependent manner. Further experiments were done in an attempt to uncover the underlying mechanism by which cimetidine exhibits free radical scavenging properties. Metal binding studies were done using electrochemical, HPLC and UV/Vis studies. The results show that cimetidine binds iron and copper. These metals have been implicated in free radical production via the Fenton reaction. By binding with cimetidine the metals become unavailable to produce free radicals and hence cimetidine indirectly reduces the formation of free radicals. The final experiment was the determination of cimetidine as a hydroxyl radical scavenger in the deoxyribose assay. Cimetidine was shown to act as a potent hydroxyl radical scavenger, thereby confirming its activity as a free radical scavenger. In addition, cimetidine protects against damage to the deoxyribose sugar, a component of DNA. Whilst there are many theories that explain the therapeutic role of cimetidine in degenerative disease, the actual mechanism of the role of cimetidine is emphasized as a free radical scavenger. Regardless of the mechanism of action, cimetidine does inhibit tumour growth according to this study and also reduce free radical levels in neurodegeneration, which suggests a role for cimetidine as a possible additive in treatment of patients with such disease states. These findings have important clinical implications, and needs to be investigated further.
- Full Text:
- Date Issued: 2003
Occupational medical examinations and labour law
- Authors: Lapere, Jan Noel Romain
- Date: 2003
- Subjects: Employees -- Medical examinations -- South Africa , Labor laws and legislation -- South Africa , Medical screening -- South Africa , Industrial hygiene -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11045 , http://hdl.handle.net/10948/302 , Employees -- Medical examinations -- South Africa , Labor laws and legislation -- South Africa , Medical screening -- South Africa , Industrial hygiene -- South Africa
- Description: South Africa’s Constitution and the Employment Equity Act have a major impact on the performance of medical examinations within the employment relationship. Health and safety statutes list a number of occupational medical examinations, which an employer must perform. Other legislation permits the execution of medical examinations. After listing the different statutory references to occupational medical examinations, this treatise examines under which conditions medical testing is required or permissible. The fairness of employment discrimination based on medical facts, employment conditions, social policy, distribution of employee benefits and inherent job requirement is analysed through a study of the legal texts, experts’ opinions and case studies. The particularities of the ethical and legal duties of the medical professional, performing the occupational medical examination, are also examined. Finally, a comprehensive analysis of the different forms of occupational medical examinations is compiled by combining legal and policy-related job requirements and is attached as an annexure. This is the practical result of the research in this treatise combined with the personal experience of the author.
- Full Text:
- Date Issued: 2003
- Authors: Lapere, Jan Noel Romain
- Date: 2003
- Subjects: Employees -- Medical examinations -- South Africa , Labor laws and legislation -- South Africa , Medical screening -- South Africa , Industrial hygiene -- South Africa
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:11045 , http://hdl.handle.net/10948/302 , Employees -- Medical examinations -- South Africa , Labor laws and legislation -- South Africa , Medical screening -- South Africa , Industrial hygiene -- South Africa
- Description: South Africa’s Constitution and the Employment Equity Act have a major impact on the performance of medical examinations within the employment relationship. Health and safety statutes list a number of occupational medical examinations, which an employer must perform. Other legislation permits the execution of medical examinations. After listing the different statutory references to occupational medical examinations, this treatise examines under which conditions medical testing is required or permissible. The fairness of employment discrimination based on medical facts, employment conditions, social policy, distribution of employee benefits and inherent job requirement is analysed through a study of the legal texts, experts’ opinions and case studies. The particularities of the ethical and legal duties of the medical professional, performing the occupational medical examination, are also examined. Finally, a comprehensive analysis of the different forms of occupational medical examinations is compiled by combining legal and policy-related job requirements and is attached as an annexure. This is the practical result of the research in this treatise combined with the personal experience of the author.
- Full Text:
- Date Issued: 2003
The effects of goat browsing on ecosystem patterns and processes in succulent thicket, South Africa
- Lechmere-Oertel, Richard Geoffrey
- Authors: Lechmere-Oertel, Richard Geoffrey
- Date: 2003
- Subjects: Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11074 , http://hdl.handle.net/10948/309 , Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Description: Transformation in the arid succulent thicket of the Eastern Cape of South Africa in response to unsustainable livestock production has been widespread, with less than 10 percent remaining intact. Transformation in succulent thicket has resulted in large areas of dense thicket (comprising a two-phase mosaic of perennial-vegetated patches separated by animal paths and bare patches) being replaced with a ‘pseudo-savanna’ of remnant canopy trees with a structurally simple field layer of ephemeral and short- lived perennial grasses and forbs. There is an extensive literature describing the transformation of succulent thicket, with many speculative statements about the underlying mechanisms of transformation. The central focus of this study was to improve our mechanistic understanding of transformation in succulent thicket using field experiments. Hopefully these results will set another foundation upon which future management of succulent thicket can be improved and large-scale restoration initiated. This study comprises four themes that are linked to the concept of landscape function. The central premise of landscape function is that functional landscapes have mechanisms that capture and retain scarce resources. Conversely, as landscapes become increasingly dysfunctional, so these mechanisms become disrupted. In succulent thicket, dysfunctio n appears to be linked to the reduced ability to harvest water, cycle carbon and a loss of organic carbon. In this thesis I examined some of the key processes that influence water and organic carbon fluxes: perennial vegetation cover, soil fertility, litter fall and decomposition, and runoff and soil erosion. The experimental design that was used for all this work was a factorial ANOVA based on replicated fenceline contrasts that reflect differences in long-term management history. The main objectives of this thesis were to: quantify the patterns of transformation in an arid form of succulent thicket, including changes in the biomass, cover and structure of the dominant vegetation guilds; test the stability of the transformed succulent thicket ecosystem to show whether it is a new stable state or an intermediate stage in a trajectory towards a highly desertified state where only the ephemeral grasses and forbs persist; describe and compare soil fertility across transformation contrasts, concentrating on changes in the spatial patterns of soil resources and the ability of the soil to harvest precipitation; to compare litter fall and decomposition of leaf material from the dominant plants in intact and transformed succulent thicket; to quantify and compare run-off and erosion from run-off plots in intact and transformed succulent thicket. Transformation and stability I quantified the changes in plant diversity, physiognomy and biomass that occur across transformation contrasts. Thicket transformation results in a significant loss of plant diversity and functional types. There is also a significant reduction in the biomass (c. 80 t.ha-1) and structural complexity of the vegetation, both vertically and horizontally. These results were interpreted in terms of their implications for ecosystem functioning and stability. To test the stability of the transformed succulent thicket I used aerial photographs and ground-truthing to track the survivorship of canopy trees over 60 years in pseudo-savanna landscapes. I also measured seedling establishment in different habitats. I show that the pseudo-savanna is not a stable state owing to ongoing adult mortality and no recruitment of canopy trees. Soil fertility and water status I hypothesised that the above-ground changes in ve getation would be accompanied by similar trends in the pattern and levels of soil nutrient resources and the ability of the landscape to harvest precipitation. I compared soil fertility (organic carbon, available nitrogen and phosphorus), texture, matric potential, and surface micro-topography in the two main micro- habitats on either side of the replicated fenceline contrasts. The results show that intact spekboom thicket has a distinct spatial pattern of soil fertility where nutrients and organic carbon are concentrated under the patches of perennial shrubs, compared to under canopy trees and open spaces. Transformation results in a significant homogenisation out of this pattern and an overall reduction in the fertility of the landscape. The proportion of the landscape surface that would promote infiltration of water decreases from 60 – 0.6 percent. Soil moisture retention (matric potential) also decreases with transformation. I interpreted these patterns in terms of the ability of the landscape to harvest and release water after rainfall events. Litter fall and decomposition Surface litter and soil organic matter are critical components to wooded ecosystems; contributing to several ecosystem functions. The rates of litter fall and decomposition are ratelimiting steps in nutrient cycling and incorporation of organic matter into the soil. The ecological mechanisms behind the collapse of succulent thicket in the face of domestic herbivory are not fully understood, but are believed to include the breakdown of several ecosystem processes, including litter fall and decomposition. I quantified the changes in litter fall and litter decomposition of four of the dominant perennial woody plants (Euclea undulata, Pappea capensis, Portulacaria afra and Rhus longispina) across the replicated fenceline. Litter fall was measured over 14 months using mesh traps. Decomposition was measured over 15 months using a combination of litterbags and unprotected leaf packs. I also quantified soil microclimate during the experimental period; hypothesising that transformation would lead to soil conditions less amenable for biotic activity. Litter fall in succulent thicket was very high for a semi-arid system, comparing more to temperate forests. The leaf-succulent P. afra contributed the largest single component of the total litter production at a landscape scale. The effect of transformation on litter fall was species specific. Deep-rooted or drought-adapted species showed no change in litter yield with transformation; shallow-rooted species showed a significant decrease. There were few significant differences in decomposition rates across the transformation gradient and between litter types. Portulacaria afra litter had the steepest rate of mass loss, and was most affected by transformation. The more recalcitrant (high C:N ratio) leaves of P. capensis remained largely unaffected by transformation. These results indicate the critical role of the perennial vegetation in incorporating organic carbon into the soil. Transformation of succulent thicket leads to a disruption of the flow of carbon into the soil, reinforcing the cycle of transformation through reduced fertility. Rehabilitation of this ecosystem will require the active establishment of species, such as P. afra, that will restart the flow of carbon into the soil. Run-off & Erosion The landscape function model predicts that functional semi-arid shrublands efficiently conserve limiting resources such as water and water-bourn sediments (soil and organic matter). As these rangelands become transformed through unsustainable livestock production, so their ability to conserve resources decreases. The primary determinant of landscape function and conservation of resources appears to be the proportional cover of perennial vegetation. I hypothesised that the switch from a two-phase mosaic dominated by perennial succulent and woody shrubs to a single phase system dominated by an ephemeral field layer would be accompanied by disruption of the mechanisms that conserve resources. Specifically, I tested the hypothesis that transformation of succulent thicket increases runoff volume, sediment concentration of runoff, soil erosion and loss of organic matter at a patch scale (c. 100 m2). Runoff and water-borne sediment were measured from runoff plots established across replicated fenceline contrasts. Data were collected from eight extreme weather events over two years. There were no significant differences between runoff and erosion across the transformation contrast, as each extreme weather event was unique in terms of its runoff response. The transformed runoff plots alone also gave inconsistent results, largely due to differences in the cover of ephemeral forbs and weakly perennial grasses. Runoff and erosion were not predictable from the data across the transformation gradient due to complex interactions between the nature of the above-ground vegetation, soil micro-topography and land use history. The results highlighted the need for longer-term catchment experiments to generate a predictive understanding of the effect of transformation on runoff and erosion in succulent thicket.
- Full Text:
- Date Issued: 2003
- Authors: Lechmere-Oertel, Richard Geoffrey
- Date: 2003
- Subjects: Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:11074 , http://hdl.handle.net/10948/309 , Succulent plants -- South Africa -- Eastern Cape , Landscape ecology -- South Africa -- Eastern Cape , Goats -- Feeding and feeds
- Description: Transformation in the arid succulent thicket of the Eastern Cape of South Africa in response to unsustainable livestock production has been widespread, with less than 10 percent remaining intact. Transformation in succulent thicket has resulted in large areas of dense thicket (comprising a two-phase mosaic of perennial-vegetated patches separated by animal paths and bare patches) being replaced with a ‘pseudo-savanna’ of remnant canopy trees with a structurally simple field layer of ephemeral and short- lived perennial grasses and forbs. There is an extensive literature describing the transformation of succulent thicket, with many speculative statements about the underlying mechanisms of transformation. The central focus of this study was to improve our mechanistic understanding of transformation in succulent thicket using field experiments. Hopefully these results will set another foundation upon which future management of succulent thicket can be improved and large-scale restoration initiated. This study comprises four themes that are linked to the concept of landscape function. The central premise of landscape function is that functional landscapes have mechanisms that capture and retain scarce resources. Conversely, as landscapes become increasingly dysfunctional, so these mechanisms become disrupted. In succulent thicket, dysfunctio n appears to be linked to the reduced ability to harvest water, cycle carbon and a loss of organic carbon. In this thesis I examined some of the key processes that influence water and organic carbon fluxes: perennial vegetation cover, soil fertility, litter fall and decomposition, and runoff and soil erosion. The experimental design that was used for all this work was a factorial ANOVA based on replicated fenceline contrasts that reflect differences in long-term management history. The main objectives of this thesis were to: quantify the patterns of transformation in an arid form of succulent thicket, including changes in the biomass, cover and structure of the dominant vegetation guilds; test the stability of the transformed succulent thicket ecosystem to show whether it is a new stable state or an intermediate stage in a trajectory towards a highly desertified state where only the ephemeral grasses and forbs persist; describe and compare soil fertility across transformation contrasts, concentrating on changes in the spatial patterns of soil resources and the ability of the soil to harvest precipitation; to compare litter fall and decomposition of leaf material from the dominant plants in intact and transformed succulent thicket; to quantify and compare run-off and erosion from run-off plots in intact and transformed succulent thicket. Transformation and stability I quantified the changes in plant diversity, physiognomy and biomass that occur across transformation contrasts. Thicket transformation results in a significant loss of plant diversity and functional types. There is also a significant reduction in the biomass (c. 80 t.ha-1) and structural complexity of the vegetation, both vertically and horizontally. These results were interpreted in terms of their implications for ecosystem functioning and stability. To test the stability of the transformed succulent thicket I used aerial photographs and ground-truthing to track the survivorship of canopy trees over 60 years in pseudo-savanna landscapes. I also measured seedling establishment in different habitats. I show that the pseudo-savanna is not a stable state owing to ongoing adult mortality and no recruitment of canopy trees. Soil fertility and water status I hypothesised that the above-ground changes in ve getation would be accompanied by similar trends in the pattern and levels of soil nutrient resources and the ability of the landscape to harvest precipitation. I compared soil fertility (organic carbon, available nitrogen and phosphorus), texture, matric potential, and surface micro-topography in the two main micro- habitats on either side of the replicated fenceline contrasts. The results show that intact spekboom thicket has a distinct spatial pattern of soil fertility where nutrients and organic carbon are concentrated under the patches of perennial shrubs, compared to under canopy trees and open spaces. Transformation results in a significant homogenisation out of this pattern and an overall reduction in the fertility of the landscape. The proportion of the landscape surface that would promote infiltration of water decreases from 60 – 0.6 percent. Soil moisture retention (matric potential) also decreases with transformation. I interpreted these patterns in terms of the ability of the landscape to harvest and release water after rainfall events. Litter fall and decomposition Surface litter and soil organic matter are critical components to wooded ecosystems; contributing to several ecosystem functions. The rates of litter fall and decomposition are ratelimiting steps in nutrient cycling and incorporation of organic matter into the soil. The ecological mechanisms behind the collapse of succulent thicket in the face of domestic herbivory are not fully understood, but are believed to include the breakdown of several ecosystem processes, including litter fall and decomposition. I quantified the changes in litter fall and litter decomposition of four of the dominant perennial woody plants (Euclea undulata, Pappea capensis, Portulacaria afra and Rhus longispina) across the replicated fenceline. Litter fall was measured over 14 months using mesh traps. Decomposition was measured over 15 months using a combination of litterbags and unprotected leaf packs. I also quantified soil microclimate during the experimental period; hypothesising that transformation would lead to soil conditions less amenable for biotic activity. Litter fall in succulent thicket was very high for a semi-arid system, comparing more to temperate forests. The leaf-succulent P. afra contributed the largest single component of the total litter production at a landscape scale. The effect of transformation on litter fall was species specific. Deep-rooted or drought-adapted species showed no change in litter yield with transformation; shallow-rooted species showed a significant decrease. There were few significant differences in decomposition rates across the transformation gradient and between litter types. Portulacaria afra litter had the steepest rate of mass loss, and was most affected by transformation. The more recalcitrant (high C:N ratio) leaves of P. capensis remained largely unaffected by transformation. These results indicate the critical role of the perennial vegetation in incorporating organic carbon into the soil. Transformation of succulent thicket leads to a disruption of the flow of carbon into the soil, reinforcing the cycle of transformation through reduced fertility. Rehabilitation of this ecosystem will require the active establishment of species, such as P. afra, that will restart the flow of carbon into the soil. Run-off & Erosion The landscape function model predicts that functional semi-arid shrublands efficiently conserve limiting resources such as water and water-bourn sediments (soil and organic matter). As these rangelands become transformed through unsustainable livestock production, so their ability to conserve resources decreases. The primary determinant of landscape function and conservation of resources appears to be the proportional cover of perennial vegetation. I hypothesised that the switch from a two-phase mosaic dominated by perennial succulent and woody shrubs to a single phase system dominated by an ephemeral field layer would be accompanied by disruption of the mechanisms that conserve resources. Specifically, I tested the hypothesis that transformation of succulent thicket increases runoff volume, sediment concentration of runoff, soil erosion and loss of organic matter at a patch scale (c. 100 m2). Runoff and water-borne sediment were measured from runoff plots established across replicated fenceline contrasts. Data were collected from eight extreme weather events over two years. There were no significant differences between runoff and erosion across the transformation contrast, as each extreme weather event was unique in terms of its runoff response. The transformed runoff plots alone also gave inconsistent results, largely due to differences in the cover of ephemeral forbs and weakly perennial grasses. Runoff and erosion were not predictable from the data across the transformation gradient due to complex interactions between the nature of the above-ground vegetation, soil micro-topography and land use history. The results highlighted the need for longer-term catchment experiments to generate a predictive understanding of the effect of transformation on runoff and erosion in succulent thicket.
- Full Text:
- Date Issued: 2003
The development of a financial performance measurement framework for South African education institutions
- Authors: Leo, Terrance
- Date: 2003
- Subjects: Universities and colleges -- South Africa -- Finance , Universities and colleges -- South Africa -- Evaluation , Performance -- Measurement
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10903 , http://hdl.handle.net/10948/217 , Universities and colleges -- South Africa -- Finance , Universities and colleges -- South Africa -- Evaluation , Performance -- Measurement
- Description: Limited research has been conducted on financial performance indicators in South Africa. In European countries, Australia and the United States of America, literature has shown that there has been extensive research and implementation of performance indicators, to measure the achievements of objectives. A literature study was conducted for this research on the usage of PI’s, with a view to pinpointing the financial indicators. The literature study was used to develop a questionnaire. The questionnaire was distributed to universities and Technikons in South Africa, to obtain a measure of relevance and agreement on the performance indicators. The findings of the questionnaire culminated in a model that only consists of those indicators with a high level of concurrence among respondents. Performance indicators can serve as a management tool to measure performance and as a means to enhance transparency and accountability.
- Full Text:
- Date Issued: 2003
- Authors: Leo, Terrance
- Date: 2003
- Subjects: Universities and colleges -- South Africa -- Finance , Universities and colleges -- South Africa -- Evaluation , Performance -- Measurement
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10903 , http://hdl.handle.net/10948/217 , Universities and colleges -- South Africa -- Finance , Universities and colleges -- South Africa -- Evaluation , Performance -- Measurement
- Description: Limited research has been conducted on financial performance indicators in South Africa. In European countries, Australia and the United States of America, literature has shown that there has been extensive research and implementation of performance indicators, to measure the achievements of objectives. A literature study was conducted for this research on the usage of PI’s, with a view to pinpointing the financial indicators. The literature study was used to develop a questionnaire. The questionnaire was distributed to universities and Technikons in South Africa, to obtain a measure of relevance and agreement on the performance indicators. The findings of the questionnaire culminated in a model that only consists of those indicators with a high level of concurrence among respondents. Performance indicators can serve as a management tool to measure performance and as a means to enhance transparency and accountability.
- Full Text:
- Date Issued: 2003
Glasbury man made Clyro bells
- Authors: Lewis, Colin A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6182 , http://hdl.handle.net/10962/d1012377
- Description: [From Introduction] There must have been great excitement in Clyro in 1708. The existing four bells in St Michael's Church were recast by Henry Williams, the bell founder from Glasbury, into a ring of five bells. The work was apparently paid for by the owners of two of the great houses in the parish: Cabalva and Lloyney. Little is known of the four bells that existed in Clyro before Williams began his work, although they appear to have been larger than the five bells cast from their metal. The four bells swung side by side in a wooden frame in the tower of the church. This frame was altered in 1708 to accommodate bells of smaller dimensions and a fifth bell pit was added at right angles to the others. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 2003
- Authors: Lewis, Colin A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6182 , http://hdl.handle.net/10962/d1012377
- Description: [From Introduction] There must have been great excitement in Clyro in 1708. The existing four bells in St Michael's Church were recast by Henry Williams, the bell founder from Glasbury, into a ring of five bells. The work was apparently paid for by the owners of two of the great houses in the parish: Cabalva and Lloyney. Little is known of the four bells that existed in Clyro before Williams began his work, although they appear to have been larger than the five bells cast from their metal. The four bells swung side by side in a wooden frame in the tower of the church. This frame was altered in 1708 to accommodate bells of smaller dimensions and a fifth bell pit was added at right angles to the others. , Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 2003
Peals in Africa
- Authors: Lewis, Colin A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6166 , http://hdl.handle.net/10962/d1012354
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 2003
- Authors: Lewis, Colin A
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6166 , http://hdl.handle.net/10962/d1012354
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa.
- Full Text:
- Date Issued: 2003
The long term effects of fire frequency and season on the colophospermum mopane shrubveld of the Kruger National Park
- Lombard, Pieter Jacobus Lategan
- Authors: Lombard, Pieter Jacobus Lategan
- Date: 2003
- Subjects: Mopane tree -- Effect of fires on -- South Africa -- Kruger National Park
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10970 , http://hdl.handle.net/10948/257 , Mopane tree -- Effect of fires on -- South Africa -- Kruger National Park
- Description: Background : The recorded history of veld burning in the Kruger National Park (KNP) started with the appointment of Colonel James Stevenson-Hamilton as warden of the Park (then the Sabie Game Reserve) in July 1912 and can be divided into five periods: From 1912 to 1926, a haphazard, and indecisive burning policy was practiced, mainly due to the perception that fire was unfavourable for the environment and because the means to combat veld fires were very meagre. From 1926 to 1948, in which period it was realized that fire was not only unavoidable over a large area such as the KNP, but also actually desirable, necessary and beneficial when applied with circumspection. During this period the capability to successfully introduce and apply a definite fire policy did not exist. From 1948 to 1956, prescribed burning was not practiced, but a network of graded firebreaks was being established (to create burning blocks), and wild fires were actively combated. From 1957 to 1993, during which period a definite prescribed burning policy was practiced, amended several times, but basically consisting of a triennial rotational system where blocks were burned by management. All fires of non-management ignition sources were combated. From 1993 to the present, when a policy of allowing lightning-ignited fires to burn freely was introduced, and fires of human origin were suppressed. The shift away from a rigid prescribed burning programme was because of the concern that the dominance of grass species characteristic of over utilised veld was a result of too frequent burning (Potgieter, 2001). Lightning fires probably played just as an important role in shaping African savanna in pre-industrial times as anthropogenic fires caused by preindustrial man. The role of post-industrial man as far as its influence on the creation of savanna is concerned is probably negligible, but significantly important in the role of maintaining savanna, although probably not more so than that of lighting fires. Fires caused by postindustrial man becomes suspect as far as the creation of savanna is concerned, because instead of the mere burning of the veld for the pure reasons of survival as practiced by pre-industrial man, a measure of commercialism crept in (Potgieter, 2001). Fire management of the KNP in pre-industrial times can be regarded in the same light as that of post-industrial times. Although the motive for burning the veld in the KNP was beyond reproach, the underlying reasoning was not. Managers’ thinking was geared towards preventing so called “devastating fires”, laying to waste large areas of the Park, not realising that this was in actual fact nature going about its business in this ecosystem. They therefore devised a system of firebreak roads, which was gradually extended to the extent that we now have more than 4000 km roads that must be maintained. This was all in the cause of preventing or managing lightning and arson fires. Given the above, a revision of the veld fire policy was extremely necessary. The mission statement hammered out during the revising process in 1993 underscored and supported the proposal put forward in 1992, that lightning fires should be recognised as a legitimate and completely natural phenomenon in the Lowveld ecosystem. This had to be weighed against the prevailing practice of combating all fires caused by lightning and non-management anthropogenic sources of fire. The essence of this policy would therefore be to allow lightning-fires to burn to their full extent i.e. if vegetation conditions (available biomass) are such that large areas will burn, then such burns will be permitted to proceed to their full extent with the provision that no more than 50% of the management unit will be allowed to burn out (no matter what the ignition source) in a specific fire season (Potgieter, 2001).
- Full Text:
- Date Issued: 2003
- Authors: Lombard, Pieter Jacobus Lategan
- Date: 2003
- Subjects: Mopane tree -- Effect of fires on -- South Africa -- Kruger National Park
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10970 , http://hdl.handle.net/10948/257 , Mopane tree -- Effect of fires on -- South Africa -- Kruger National Park
- Description: Background : The recorded history of veld burning in the Kruger National Park (KNP) started with the appointment of Colonel James Stevenson-Hamilton as warden of the Park (then the Sabie Game Reserve) in July 1912 and can be divided into five periods: From 1912 to 1926, a haphazard, and indecisive burning policy was practiced, mainly due to the perception that fire was unfavourable for the environment and because the means to combat veld fires were very meagre. From 1926 to 1948, in which period it was realized that fire was not only unavoidable over a large area such as the KNP, but also actually desirable, necessary and beneficial when applied with circumspection. During this period the capability to successfully introduce and apply a definite fire policy did not exist. From 1948 to 1956, prescribed burning was not practiced, but a network of graded firebreaks was being established (to create burning blocks), and wild fires were actively combated. From 1957 to 1993, during which period a definite prescribed burning policy was practiced, amended several times, but basically consisting of a triennial rotational system where blocks were burned by management. All fires of non-management ignition sources were combated. From 1993 to the present, when a policy of allowing lightning-ignited fires to burn freely was introduced, and fires of human origin were suppressed. The shift away from a rigid prescribed burning programme was because of the concern that the dominance of grass species characteristic of over utilised veld was a result of too frequent burning (Potgieter, 2001). Lightning fires probably played just as an important role in shaping African savanna in pre-industrial times as anthropogenic fires caused by preindustrial man. The role of post-industrial man as far as its influence on the creation of savanna is concerned is probably negligible, but significantly important in the role of maintaining savanna, although probably not more so than that of lighting fires. Fires caused by postindustrial man becomes suspect as far as the creation of savanna is concerned, because instead of the mere burning of the veld for the pure reasons of survival as practiced by pre-industrial man, a measure of commercialism crept in (Potgieter, 2001). Fire management of the KNP in pre-industrial times can be regarded in the same light as that of post-industrial times. Although the motive for burning the veld in the KNP was beyond reproach, the underlying reasoning was not. Managers’ thinking was geared towards preventing so called “devastating fires”, laying to waste large areas of the Park, not realising that this was in actual fact nature going about its business in this ecosystem. They therefore devised a system of firebreak roads, which was gradually extended to the extent that we now have more than 4000 km roads that must be maintained. This was all in the cause of preventing or managing lightning and arson fires. Given the above, a revision of the veld fire policy was extremely necessary. The mission statement hammered out during the revising process in 1993 underscored and supported the proposal put forward in 1992, that lightning fires should be recognised as a legitimate and completely natural phenomenon in the Lowveld ecosystem. This had to be weighed against the prevailing practice of combating all fires caused by lightning and non-management anthropogenic sources of fire. The essence of this policy would therefore be to allow lightning-fires to burn to their full extent i.e. if vegetation conditions (available biomass) are such that large areas will burn, then such burns will be permitted to proceed to their full extent with the provision that no more than 50% of the management unit will be allowed to burn out (no matter what the ignition source) in a specific fire season (Potgieter, 2001).
- Full Text:
- Date Issued: 2003