The "old-new" challenges of water, sanitation and bioremediation in developing countries
- Authors: Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75982 , vital:30489 , DOI: 10.4172/2155-6199.1000e152
- Description: Developing countries face challenges in the development of infrastructure and population growth. These lead to “side-effects" such as uncontrolled urbanization and the fact that basic services such as water and sanitation are lagging behind the actual needs on the ground. Historical challenges, lack of skilled staff and often lack of sustained funding are some of the reasons for the status quo. Extent of water and sanitation coverage often forces national and local governments to install the minimum-standard solutions, e.g. the ventilated improved pit latrines. This improves the public health status in the short-term, but causes problem in the long run due to the lack of regular maintenance such as through lack emptying of pits. Sometimes, construction of these facilities is of inferior standard. Pits are often built without lining or zero consideration is given to the local conditions in terms of soil properties, water table and the number of toilet users.
- Full Text:
- Date Issued: 2014
- Authors: Tandlich, Roman
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75982 , vital:30489 , DOI: 10.4172/2155-6199.1000e152
- Description: Developing countries face challenges in the development of infrastructure and population growth. These lead to “side-effects" such as uncontrolled urbanization and the fact that basic services such as water and sanitation are lagging behind the actual needs on the ground. Historical challenges, lack of skilled staff and often lack of sustained funding are some of the reasons for the status quo. Extent of water and sanitation coverage often forces national and local governments to install the minimum-standard solutions, e.g. the ventilated improved pit latrines. This improves the public health status in the short-term, but causes problem in the long run due to the lack of regular maintenance such as through lack emptying of pits. Sometimes, construction of these facilities is of inferior standard. Pits are often built without lining or zero consideration is given to the local conditions in terms of soil properties, water table and the number of toilet users.
- Full Text:
- Date Issued: 2014
Mulch tower treatment system for greywater reuse Part II: destructive testing and effluent treatment
- Tandlich, Roman, Zuma, Bongumusa M, Whittington-Jones, Kevin J, Burgess, Jo E
- Authors: Tandlich, Roman , Zuma, Bongumusa M , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71547 , vital:29863 , https://doi.org/10.1016/j.desal.2008.03.031
- Description: The mulch tower (MT) system described in Part I was tested to failure to determine its range of operating conditions. An increase in the influent temperature led to a statistically significant release of components of the chemical oxygen demand (COD) and the five day biochemical oxygen demand (BOD5), as well as phosphates from the MT system. Heterotrophic plate count (HPC) of the mulch layer dropped from 1.2 (± 0.6) × 106/g dry weight to 1.5 (± 0.3) × 105/g dry weight of the mulch layer with increases of the influent temperature. This indicates that the increase in influent temperature killed off some of the active biomass in the MT biofilm. After a five day drying period under active aeration, the MT system retained the ability to remove COD, total suspended solids (TSS), and nitrates. Greywater treatment by the MT system became impossible after a 48 day drying period under active aeration. Chlorination of the simulated MT effluent with a mixture of sodium dichloroisocyanurate and trichloroisocyanuric acid decreased the faecal coliform concentrations (FC) and the total coliform concentrations (TC) below 800 CFUs/100 ml within 65 h. Beyond 65 h, the pH of the effluent became highly acidic. To maintain optimum performance influent should be fed into the MT system at least once every 5 days, sufficient aeration should be guaranteed, and the MT effluent should be chlorinated for 65 h to eliminate all pathogens before any reuse.
- Full Text: false
- Date Issued: 2009
Mulch tower treatment system for greywater reuse Part II: destructive testing and effluent treatment
- Authors: Tandlich, Roman , Zuma, Bongumusa M , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71547 , vital:29863 , https://doi.org/10.1016/j.desal.2008.03.031
- Description: The mulch tower (MT) system described in Part I was tested to failure to determine its range of operating conditions. An increase in the influent temperature led to a statistically significant release of components of the chemical oxygen demand (COD) and the five day biochemical oxygen demand (BOD5), as well as phosphates from the MT system. Heterotrophic plate count (HPC) of the mulch layer dropped from 1.2 (± 0.6) × 106/g dry weight to 1.5 (± 0.3) × 105/g dry weight of the mulch layer with increases of the influent temperature. This indicates that the increase in influent temperature killed off some of the active biomass in the MT biofilm. After a five day drying period under active aeration, the MT system retained the ability to remove COD, total suspended solids (TSS), and nitrates. Greywater treatment by the MT system became impossible after a 48 day drying period under active aeration. Chlorination of the simulated MT effluent with a mixture of sodium dichloroisocyanurate and trichloroisocyanuric acid decreased the faecal coliform concentrations (FC) and the total coliform concentrations (TC) below 800 CFUs/100 ml within 65 h. Beyond 65 h, the pH of the effluent became highly acidic. To maintain optimum performance influent should be fed into the MT system at least once every 5 days, sufficient aeration should be guaranteed, and the MT effluent should be chlorinated for 65 h to eliminate all pathogens before any reuse.
- Full Text: false
- Date Issued: 2009
Biphenyl sorption to different soil clay minerals
- Tandlich, Roman, Baláž, Štefan
- Authors: Tandlich, Roman , Baláž, Štefan
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76869 , vital:30632 , https://doi.org/10.5897/AJAR10.1012
- Description: Only limited information is available in the literature on the role of soil mineral surfaces in the sorption of hydrophobic organic pollutants. This knowledge gap is addressed through the assessment of biphenyl sorption to kaolinite, illite and bentonite; using the batch equilibration technique with incubations lasting 6 or 21 days at 28 ± 2°C in the dark [RT1]. Sorption of biphenyl onto kaolinite followed the Freundlich sorption isotherm, whereas linear sorption isotherms were observed on illite and bentonite [RT2]. The biphenyl sorption partition coefficient on kaolinite ranged from 0.1 to 9.1 cm3.g-1 after 6 days and no sorption was observed after 21 days. This could have been caused by a completely reversible sorption or a loss of binding capacity after 21 days [RT3]. The respective values of the biphenyl sorption partition coefficient on illite and bentonite ranged from 20.3 ± 0.3 to 120 ± 8 cm3.g-1.Sorption equilibrium on the internal clay surfaces was reached after 6 days, as indicated by the sorption data for illite and bentonite [RT4]. Access of biphenyl molecules to the internal clay surfaces is a function of the ionic strength of soil solution and the soil organic matter is the dominant site for biphenyl sorption after 6 to 21 days.
- Full Text:
- Date Issued: 2011
- Authors: Tandlich, Roman , Baláž, Štefan
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76869 , vital:30632 , https://doi.org/10.5897/AJAR10.1012
- Description: Only limited information is available in the literature on the role of soil mineral surfaces in the sorption of hydrophobic organic pollutants. This knowledge gap is addressed through the assessment of biphenyl sorption to kaolinite, illite and bentonite; using the batch equilibration technique with incubations lasting 6 or 21 days at 28 ± 2°C in the dark [RT1]. Sorption of biphenyl onto kaolinite followed the Freundlich sorption isotherm, whereas linear sorption isotherms were observed on illite and bentonite [RT2]. The biphenyl sorption partition coefficient on kaolinite ranged from 0.1 to 9.1 cm3.g-1 after 6 days and no sorption was observed after 21 days. This could have been caused by a completely reversible sorption or a loss of binding capacity after 21 days [RT3]. The respective values of the biphenyl sorption partition coefficient on illite and bentonite ranged from 20.3 ± 0.3 to 120 ± 8 cm3.g-1.Sorption equilibrium on the internal clay surfaces was reached after 6 days, as indicated by the sorption data for illite and bentonite [RT4]. Access of biphenyl molecules to the internal clay surfaces is a function of the ionic strength of soil solution and the soil organic matter is the dominant site for biphenyl sorption after 6 to 21 days.
- Full Text:
- Date Issued: 2011
The evaluation of indomethacin and theophylline oral controlled/modified-release dosage forms in vitro-in vivo correlations
- Tandt, Ludo Alfons Germaan Luc
- Authors: Tandt, Ludo Alfons Germaan Luc
- Date: 1992
- Subjects: Theophylline , Indomethacin , Drugs -- Controlled release , Drugs -- Dosage forms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3794 , http://hdl.handle.net/10962/d1003272 , Theophylline , Indomethacin , Drugs -- Controlled release , Drugs -- Dosage forms
- Description: Over the past few decades many researchers have investigated the utility of in vitro - in vivo correlations for the assessment of dosage forms. These investigations are, however, dependent on reproducible dissolution data and well conducted biostudies in order to establish meaningful and robust correlations. Despite the fact that the establishment of such correlations is perhaps idealistic, considerable interest has still been shown in this area of research. Various Controlled/Modified Release Dosage Forms (CMRD's) of theophylline, a weakly basic drug, and indomethacin, a weakly acidic drug, were assessed in order to establish in vitro - in vivo correlations. Dissolution rate studies were carried out using either the USP basket or paddle apparatus. The dissolution rate studies were conducted in a range of dissolution media of varying pH. Bioavailability studies were conducted on the dosage forms used by the Biopharmaceutics Research Institute at Rhodes University. The results of these biostudies were kindly made available for use in this research project. Type A correlations were established using a mathematical simulation process whereby expected in vivo responses are simulated and compared to actual profiles obtained for the dosage forms. In order to perform the simulations the dissolution rate profiles were stripped and using linear regression and the methods of residuals the dissolution rate order and the relevant dissolution rates were obtained. The results of the s imulations indicated that the in vivo serum concentration-time curves could be accurately predicted for the theophylline dosage forms but to a lesser extent, for the indomethacin formulations. The dissolution rate studies indicated that the paddle method is a suitable method for dissolution rate studies of theophylline CMRD's, although it appeared that the optimum pH of the dissolution medium was formulation dependent. Dissolution rate studies conducted on indomethacin formulations indicated that the USP specified basket method for extended-release indomethacin formulations was not able to distinguish between two formulations which exhibited different in vivo profiles. The conversion to the paddle method was, however, able to highlight the differences between these formulations. The use of three dimensional topographs to depict dissolution rate profiles was demonstrated for formulations of both theophylline and indomethacin. The topographs enabled the successful differentiation between bioinequivalent formulations. The dissolution rate profiles were also fitted to the Wei bull equation and the parameters obtained from this were compared to the Weibull parameters obtained from the in vivo absorption plots obtained using the Wagner-Nelson method. The results indicated that the Weibull function was suitable to describe both the in vivo and in vitro data. The following recommendations for the preformulation dissolution studies of weakly acidic and weakly basic drugs are proposed. The dissolution rate studies of weakly acid drugs, such as indomethacin, should be carried out over a range of pH utilising the paddle apparatus. Three dimensional topographs based on the dissolution data should be constructed and used as a comparative tool for different formulations. Based on these comparisons the appropriate formulation can then be selected for a pilot scale in vivo bioavailability study. The dissolution rate studies of weakly basic drugs, such as theophylline, should be carried out over a range of pH utilising the paddle apparatus. The dissolution data should then be used to simulate the expected in vivo profile and on this basis the appropriate formulation selected for a pilot scale bioavailability study. The above approach to the preformulation studies of new CMRO's would allow for the more careful selection of new dosage forms and could thus eliminate costly and unnecessary bioavailability studies performed on inferior formulations.
- Full Text:
- Date Issued: 1992
- Authors: Tandt, Ludo Alfons Germaan Luc
- Date: 1992
- Subjects: Theophylline , Indomethacin , Drugs -- Controlled release , Drugs -- Dosage forms
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3794 , http://hdl.handle.net/10962/d1003272 , Theophylline , Indomethacin , Drugs -- Controlled release , Drugs -- Dosage forms
- Description: Over the past few decades many researchers have investigated the utility of in vitro - in vivo correlations for the assessment of dosage forms. These investigations are, however, dependent on reproducible dissolution data and well conducted biostudies in order to establish meaningful and robust correlations. Despite the fact that the establishment of such correlations is perhaps idealistic, considerable interest has still been shown in this area of research. Various Controlled/Modified Release Dosage Forms (CMRD's) of theophylline, a weakly basic drug, and indomethacin, a weakly acidic drug, were assessed in order to establish in vitro - in vivo correlations. Dissolution rate studies were carried out using either the USP basket or paddle apparatus. The dissolution rate studies were conducted in a range of dissolution media of varying pH. Bioavailability studies were conducted on the dosage forms used by the Biopharmaceutics Research Institute at Rhodes University. The results of these biostudies were kindly made available for use in this research project. Type A correlations were established using a mathematical simulation process whereby expected in vivo responses are simulated and compared to actual profiles obtained for the dosage forms. In order to perform the simulations the dissolution rate profiles were stripped and using linear regression and the methods of residuals the dissolution rate order and the relevant dissolution rates were obtained. The results of the s imulations indicated that the in vivo serum concentration-time curves could be accurately predicted for the theophylline dosage forms but to a lesser extent, for the indomethacin formulations. The dissolution rate studies indicated that the paddle method is a suitable method for dissolution rate studies of theophylline CMRD's, although it appeared that the optimum pH of the dissolution medium was formulation dependent. Dissolution rate studies conducted on indomethacin formulations indicated that the USP specified basket method for extended-release indomethacin formulations was not able to distinguish between two formulations which exhibited different in vivo profiles. The conversion to the paddle method was, however, able to highlight the differences between these formulations. The use of three dimensional topographs to depict dissolution rate profiles was demonstrated for formulations of both theophylline and indomethacin. The topographs enabled the successful differentiation between bioinequivalent formulations. The dissolution rate profiles were also fitted to the Wei bull equation and the parameters obtained from this were compared to the Weibull parameters obtained from the in vivo absorption plots obtained using the Wagner-Nelson method. The results indicated that the Weibull function was suitable to describe both the in vivo and in vitro data. The following recommendations for the preformulation dissolution studies of weakly acidic and weakly basic drugs are proposed. The dissolution rate studies of weakly acid drugs, such as indomethacin, should be carried out over a range of pH utilising the paddle apparatus. Three dimensional topographs based on the dissolution data should be constructed and used as a comparative tool for different formulations. Based on these comparisons the appropriate formulation can then be selected for a pilot scale in vivo bioavailability study. The dissolution rate studies of weakly basic drugs, such as theophylline, should be carried out over a range of pH utilising the paddle apparatus. The dissolution data should then be used to simulate the expected in vivo profile and on this basis the appropriate formulation selected for a pilot scale bioavailability study. The above approach to the preformulation studies of new CMRO's would allow for the more careful selection of new dosage forms and could thus eliminate costly and unnecessary bioavailability studies performed on inferior formulations.
- Full Text:
- Date Issued: 1992
A critical cultural review of the media coverage in the infighting of Nelson Mandela's burial in 2013
- Authors: Tandwa, Nontlahla
- Date: 2014
- Subjects: Mandela, Nelson, 1918-2013 , Mass media and culture
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/5733 , vital:20987
- Description: The aim of the study is to analyze the representation of isiXhosa traditional culture through the coverage on media coverage as the topic suggests following a legal battle on the removal of the remains of Mandela‘s children in the year 2013. The online news articles selected in this study covered issues since Mandela was in and out of hospital. The articles covered are those of local newspaper, The Herald-online- as it is based in the Eastern Cape and has covered more on the traditional beliefs, understanding and following such rituals. The aim of the study is to explore and describe the perceptions and experiences of people around the family feud and the legal battle on the removal of those remains. It will also emphasize on the representation of the media on this problem and how Xhosa tradition can be affected and also compare other newspaper articles on their coverage.
- Full Text:
- Date Issued: 2014
- Authors: Tandwa, Nontlahla
- Date: 2014
- Subjects: Mandela, Nelson, 1918-2013 , Mass media and culture
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/5733 , vital:20987
- Description: The aim of the study is to analyze the representation of isiXhosa traditional culture through the coverage on media coverage as the topic suggests following a legal battle on the removal of the remains of Mandela‘s children in the year 2013. The online news articles selected in this study covered issues since Mandela was in and out of hospital. The articles covered are those of local newspaper, The Herald-online- as it is based in the Eastern Cape and has covered more on the traditional beliefs, understanding and following such rituals. The aim of the study is to explore and describe the perceptions and experiences of people around the family feud and the legal battle on the removal of those remains. It will also emphasize on the representation of the media on this problem and how Xhosa tradition can be affected and also compare other newspaper articles on their coverage.
- Full Text:
- Date Issued: 2014
Gazing at horror: body performance in the wake of mass social trauma
- Authors: Tang, Cheong Wai Acty
- Date: 2006
- Subjects: Abramovic, Marina Performance art -- South Africa Drama -- Psychological aspects Psychic trauma Performance art -- Psychological aspects Loss (Psychology) Ritual in art Art, Modern -- 20th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2149 , http://hdl.handle.net/10962/d1002381
- Description: This thesis explores various dilemmas in making theatre performances in the context of social disruption, trauma and death. Diverse discourses are drawn in to consider issues of body, subjectivity and spectatorship, refracted through the writer’s experiences of and discontent with making theatre. Written in a fractal-like structure, rather than a linear progression, this thesis unsettles discourses of truth, thus simultaneously intervening in debates about the epistemologies of the body and of theatre in context of the academy. Chapter 1: Methodological Anxieties Psychoanalytic theory provides a way in for investigating the dynamics of theatrical performance and its corporeal presence, by focusing on desire and its implication in the notions of loss and anxiety. The theories of the unconscious and the gaze have epistemological implications, shifting definitions of “presence” and “truth” in theatre performance and writing about theatre. This chapter tries to outline the rationale for, as well as to enact, an alternative methodology for writing, as an ethical response to loss that does not insist on consensus and truth. Chapter 2: (Refusing to) Look at Trauma This chapter examines the politics that strives to make suffering visible. Discursive binaries of public/private, dead/living, and invisible/visible underlie the politics of AIDS and sexuality. These discourses impact on the reception of Bill T. Jones's choreography, despite his use of modernist artistic processes in search of a bodily presence that aims to collapse the binary of representation (text) and its subject (being). The theory of the gaze shows this politics to be a phallocentric discourse; and narrative analysis traces the metanarrative that results in the commodification of oppositional identities, so that spectators participate in the politics as consumers. An ethical artistic response thus needs to shift its focus to the subjectivity of the spectator. Chapter 3: The Screen and the Viewer’s Blindness By appealing to a transcendent reality, and by constituting spectators as a participative community, ritual theatre claims to enact change. The “truth” of ritual rests not on rational knowledge, but on the performer’s competence to produce a shamanic presence, which director Brett Bailey embraces in his early work. Ritual presence operates by identification and belonging to a father/god as the source of meaning; but it represses the loss of this originary wholeness. Spectators of ritual theatre are drawn into an enactment of communion/community, the centre of which is, however, loss/emptiness. The claim of enacting change becomes problematic for its absence of truth. Bailey attempts to perform a hybrid, postcolonial aesthetics; but the problem rests in the larger context of performing the notion of “South Africa”, a communal identity hardened around the metanarrative of suffering, abjecting those that do not belong to the land of the father/god – foreigners that unsettle the meaning of South African identity. Conclusion: Bodies of Discontent The South African stage is circumscribed by political and economic discourses; the problematization of national identity is also a problematization of image-identification in the theatre. In search for a way to unsettle these interrogative discourses, two moments of performing foreignness are examined, one fictional, one theatrical. These moments enact a parallel to the feminine hysteric, who disturbs the phallocentric truth of the psychoanalyst through body performance. These moments of disturbing spectatorship are reflected in the works of performance artist Marina Abramovic. Her explorations into passive-aggression, shamanism and finally theatricality and the morality of spectatorship allow for an overview of the issues raised in this thesis regarding body, viewing, and subjecthood. Sensitivity to the body and its discontent on the part of the viewer becomes crucial to ethical performance.
- Full Text:
- Date Issued: 2006
- Authors: Tang, Cheong Wai Acty
- Date: 2006
- Subjects: Abramovic, Marina Performance art -- South Africa Drama -- Psychological aspects Psychic trauma Performance art -- Psychological aspects Loss (Psychology) Ritual in art Art, Modern -- 20th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2149 , http://hdl.handle.net/10962/d1002381
- Description: This thesis explores various dilemmas in making theatre performances in the context of social disruption, trauma and death. Diverse discourses are drawn in to consider issues of body, subjectivity and spectatorship, refracted through the writer’s experiences of and discontent with making theatre. Written in a fractal-like structure, rather than a linear progression, this thesis unsettles discourses of truth, thus simultaneously intervening in debates about the epistemologies of the body and of theatre in context of the academy. Chapter 1: Methodological Anxieties Psychoanalytic theory provides a way in for investigating the dynamics of theatrical performance and its corporeal presence, by focusing on desire and its implication in the notions of loss and anxiety. The theories of the unconscious and the gaze have epistemological implications, shifting definitions of “presence” and “truth” in theatre performance and writing about theatre. This chapter tries to outline the rationale for, as well as to enact, an alternative methodology for writing, as an ethical response to loss that does not insist on consensus and truth. Chapter 2: (Refusing to) Look at Trauma This chapter examines the politics that strives to make suffering visible. Discursive binaries of public/private, dead/living, and invisible/visible underlie the politics of AIDS and sexuality. These discourses impact on the reception of Bill T. Jones's choreography, despite his use of modernist artistic processes in search of a bodily presence that aims to collapse the binary of representation (text) and its subject (being). The theory of the gaze shows this politics to be a phallocentric discourse; and narrative analysis traces the metanarrative that results in the commodification of oppositional identities, so that spectators participate in the politics as consumers. An ethical artistic response thus needs to shift its focus to the subjectivity of the spectator. Chapter 3: The Screen and the Viewer’s Blindness By appealing to a transcendent reality, and by constituting spectators as a participative community, ritual theatre claims to enact change. The “truth” of ritual rests not on rational knowledge, but on the performer’s competence to produce a shamanic presence, which director Brett Bailey embraces in his early work. Ritual presence operates by identification and belonging to a father/god as the source of meaning; but it represses the loss of this originary wholeness. Spectators of ritual theatre are drawn into an enactment of communion/community, the centre of which is, however, loss/emptiness. The claim of enacting change becomes problematic for its absence of truth. Bailey attempts to perform a hybrid, postcolonial aesthetics; but the problem rests in the larger context of performing the notion of “South Africa”, a communal identity hardened around the metanarrative of suffering, abjecting those that do not belong to the land of the father/god – foreigners that unsettle the meaning of South African identity. Conclusion: Bodies of Discontent The South African stage is circumscribed by political and economic discourses; the problematization of national identity is also a problematization of image-identification in the theatre. In search for a way to unsettle these interrogative discourses, two moments of performing foreignness are examined, one fictional, one theatrical. These moments enact a parallel to the feminine hysteric, who disturbs the phallocentric truth of the psychoanalyst through body performance. These moments of disturbing spectatorship are reflected in the works of performance artist Marina Abramovic. Her explorations into passive-aggression, shamanism and finally theatricality and the morality of spectatorship allow for an overview of the issues raised in this thesis regarding body, viewing, and subjecthood. Sensitivity to the body and its discontent on the part of the viewer becomes crucial to ethical performance.
- Full Text:
- Date Issued: 2006
High genetic diversity and limited spatial structure in an endangered, endemic South African sparid, the red steenbras Petrus rupestris:
- Tang, Wei, Qiu, Yuanyuan, Li, Xiaonan, Soy, Rodah C, Mack, John, Nyokong, Tebello
- Authors: Tang, Wei , Qiu, Yuanyuan , Li, Xiaonan , Soy, Rodah C , Mack, John , Nyokong, Tebello
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160390 , vital:40441 , DOI: 10.6060/mhc200183l
- Description: Earth-abundant first row transition metal corrole complexes have played an important role in fundamental research due to their unique molecular structures and attractive properties. In comparison to porphyrins, corroles have three inner N-H protons and are ring-contracted with a smaller macrocyclic cavity. First row transition metal corroles have been widely used as effective electrochemical catalysts for small molecule activations, such as hydrogen evolution, oxygen reduction/evolution and CO2 reduction reactions (HERs, ORRs/OERs and CO2 RRs) through homogenous and/or heterogenous prodecures. Several strategies have been used to modulate the catalytic efficiency of synthetic metallocorroles.
- Full Text:
- Date Issued: 2020
- Authors: Tang, Wei , Qiu, Yuanyuan , Li, Xiaonan , Soy, Rodah C , Mack, John , Nyokong, Tebello
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160390 , vital:40441 , DOI: 10.6060/mhc200183l
- Description: Earth-abundant first row transition metal corrole complexes have played an important role in fundamental research due to their unique molecular structures and attractive properties. In comparison to porphyrins, corroles have three inner N-H protons and are ring-contracted with a smaller macrocyclic cavity. First row transition metal corroles have been widely used as effective electrochemical catalysts for small molecule activations, such as hydrogen evolution, oxygen reduction/evolution and CO2 reduction reactions (HERs, ORRs/OERs and CO2 RRs) through homogenous and/or heterogenous prodecures. Several strategies have been used to modulate the catalytic efficiency of synthetic metallocorroles.
- Full Text:
- Date Issued: 2020
Kunyandi iwera
- Tanguirei, Performer not specified, Composer not specified, Tracey, Hugh
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa Zimbabwe City not specified f-rh
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342359 , vital:62883 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3744-1909
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa Zimbabwe City not specified f-rh
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342359 , vital:62883 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3744-1909
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
Kunyandi iwera
- Tanguirei, Performer not specified, Composer not specified, Tracey, Hugh
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa Zimbabwe City not specified f-rh
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342369 , vital:62885 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3745-1909
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa Zimbabwe City not specified f-rh
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342369 , vital:62885 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3745-1909
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
Rungano rgweShato Nyangara
- Tanguirei, Performer not specified, Composer not specified, Tracey, Hugh
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa South Africa Cape town f-sa
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342423 , vital:62887 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3746-1908.1
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa South Africa Cape town f-sa
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342423 , vital:62887 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3746-1908.1
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
Rungano rgweShato Nyangara
- Tanguirei, Performer not specified, Composer not specified, Tracey, Hugh
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa South Africa Cape town f-sa
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342401 , vital:62888 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3746-1908.1
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
- Authors: Tanguirei , Performer not specified , Composer not specified , Tracey, Hugh
- Date: 1943
- Subjects: Folk Music , Field recordings , Africa, Sub-Saharan , Africa South Africa Cape town f-sa
- Language: Shona
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/342401 , vital:62888 , International Library of African Music, Rhodes University, Makhanda, South Africa , Hugh Tracey Commercial Records, Rhodes University, Makhanda, South Africa , TP3746-1908.1
- Description: Indigenous music
- Full Text: false
- Date Issued: 1943
An assessment of the implementation of peer academic support programmes at higher education institutions in South Africa: a case study of one university
- Authors: Tangwe, Magdaline Nji
- Date: 2013
- Subjects: Peer teaching -- South Africa , Education, Higher -- South Africa
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:16203 , http://hdl.handle.net/10353/d1016084 , Peer teaching -- South Africa , Education, Higher -- South Africa
- Description: The purpose of the study was to assess the implementation of peer academic support programmes which are Language and Writing Advancement and Supplemental Instruction programmes in one University in South Africa. The study adopted a qualitative approach that used face-to-face interviews, focus group interviews and document analysis to collect data. Purposive sampling was used to select those who participated in the study. The participants were two coordinators of the programmes, ten facilitators working in the programmes for in-depth interviews and ten students who have been receiving services from the programmes for two focus group discussions. The study revealed that there was a general trend whereby peer facilitators of the programmes were recruited and trained. However, it was found that some facilitators abandoned the position immediately after the training which made it difficult for coordinators and Human Resource Staff (HR) to start the process of recruitment and retraining. In this regard, Teaching and Learning Centre, (TLC) and HR simply appointed other untrained facilitators to replace those who had deserted the positions. Also, some facilitators were unable to attend some of the regular trainings because of clashes with their classes. All these have a negative impact on the implementation of the programmes. The results also reveal that some of the facilitators were frustrated with students’ poor attendance in the sessions, and even those who attended their sessions, did not participate much in the discussions. It was found that most lecturers and students did not know the differences between supplemental instruction (SI) and tutorials. Neither did lecturers encourage their students to seek help from the TLC services. Reviewing of assignments from different disciplines by TLC facilitators was another burning issue that came up. Some facilitators reviewed assignments from different disciplines, because the disciplines were not represented and this is because they want to claim for more hours, which affects the quality of the programmes. The findings also show that some students did not like to take their assignment to the TLC for review because facilitators make unnecessary and harsh comments. On the contrary, some students acknowledged that they were fine with the way facilitators review assignments because it involves one-on-one consultation, and they always pass the assignments reviewed by PASS facilitators. The study also revealed that the coordinators monitored and evaluated facilitators through observation and the checking of attendance registers. Coordinators ware also monitored by senior colleagues of the department such as the manager of the TLC. Furthermore TLC has instituted a mentorship programme whereby senior facilitators mentor newly recruited facilitators. However not every facilitator had a mentor. The study also exposed the fact that the TLC venue was usually closed during examination periods to allow facilitators to prepare for their examinations. The findings show that some departments were not represented by facilitators and to remedy this situation, it is recommended that all departments be represented and lecturers encourage the students to get help from TLC. Most facilitators were undergraduate students, but they needed to be replaced by post graduates who did not have course work that will clash with PASS activities. The strategies used by facilitators were fairly good but more should be done to encourage students to participate in sessions. Finally, the monitoring and support mechanisms put in place were very functional but the TLC should make sure every facilitator is being monitored especially concerning the review of assignments. The significance of the findings of this study cannot be overemphasised. The strengths and challenges regarding the implementation of these programmes at this particular university have been revealed. Through the recommendations, it is hoped that the institution and the TLC would effect some changes in the implementation of these peer academic support programmes in order to better serve the students so as to achieve satisfactory throughput and retention rates.
- Full Text:
- Date Issued: 2013
- Authors: Tangwe, Magdaline Nji
- Date: 2013
- Subjects: Peer teaching -- South Africa , Education, Higher -- South Africa
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:16203 , http://hdl.handle.net/10353/d1016084 , Peer teaching -- South Africa , Education, Higher -- South Africa
- Description: The purpose of the study was to assess the implementation of peer academic support programmes which are Language and Writing Advancement and Supplemental Instruction programmes in one University in South Africa. The study adopted a qualitative approach that used face-to-face interviews, focus group interviews and document analysis to collect data. Purposive sampling was used to select those who participated in the study. The participants were two coordinators of the programmes, ten facilitators working in the programmes for in-depth interviews and ten students who have been receiving services from the programmes for two focus group discussions. The study revealed that there was a general trend whereby peer facilitators of the programmes were recruited and trained. However, it was found that some facilitators abandoned the position immediately after the training which made it difficult for coordinators and Human Resource Staff (HR) to start the process of recruitment and retraining. In this regard, Teaching and Learning Centre, (TLC) and HR simply appointed other untrained facilitators to replace those who had deserted the positions. Also, some facilitators were unable to attend some of the regular trainings because of clashes with their classes. All these have a negative impact on the implementation of the programmes. The results also reveal that some of the facilitators were frustrated with students’ poor attendance in the sessions, and even those who attended their sessions, did not participate much in the discussions. It was found that most lecturers and students did not know the differences between supplemental instruction (SI) and tutorials. Neither did lecturers encourage their students to seek help from the TLC services. Reviewing of assignments from different disciplines by TLC facilitators was another burning issue that came up. Some facilitators reviewed assignments from different disciplines, because the disciplines were not represented and this is because they want to claim for more hours, which affects the quality of the programmes. The findings also show that some students did not like to take their assignment to the TLC for review because facilitators make unnecessary and harsh comments. On the contrary, some students acknowledged that they were fine with the way facilitators review assignments because it involves one-on-one consultation, and they always pass the assignments reviewed by PASS facilitators. The study also revealed that the coordinators monitored and evaluated facilitators through observation and the checking of attendance registers. Coordinators ware also monitored by senior colleagues of the department such as the manager of the TLC. Furthermore TLC has instituted a mentorship programme whereby senior facilitators mentor newly recruited facilitators. However not every facilitator had a mentor. The study also exposed the fact that the TLC venue was usually closed during examination periods to allow facilitators to prepare for their examinations. The findings show that some departments were not represented by facilitators and to remedy this situation, it is recommended that all departments be represented and lecturers encourage the students to get help from TLC. Most facilitators were undergraduate students, but they needed to be replaced by post graduates who did not have course work that will clash with PASS activities. The strategies used by facilitators were fairly good but more should be done to encourage students to participate in sessions. Finally, the monitoring and support mechanisms put in place were very functional but the TLC should make sure every facilitator is being monitored especially concerning the review of assignments. The significance of the findings of this study cannot be overemphasised. The strengths and challenges regarding the implementation of these programmes at this particular university have been revealed. Through the recommendations, it is hoped that the institution and the TLC would effect some changes in the implementation of these peer academic support programmes in order to better serve the students so as to achieve satisfactory throughput and retention rates.
- Full Text:
- Date Issued: 2013
The impact of motivations, personal values, management skills of managers on the perfomance of SME`s in selected towns (Port Elizabeth and Port Alfred) in the Eastern Cape Province, South Africa
- Authors: Tangwo, Asah Francis
- Date: 2012
- Subjects: Executives -- South Africa -- Eastern Cape , Labor turnover -- South Africa -- Eastern Cape , Organizational commitment -- South Africa -- Eastern Cape , Employee morale -- South Africa -- Eastern Cape , Employee loyalty -- South Africa -- Eastern Cape , Employee motivation -- South Africa -- Eastern Cape , Personalism , Small business -- South Africa -- Eastern Cape , Performance -- Management
- Language: English
- Type: Thesis , Masters , M Com (Business Management)
- Identifier: vital:11320 , http://hdl.handle.net/10353/d1007046 , Executives -- South Africa -- Eastern Cape , Labor turnover -- South Africa -- Eastern Cape , Organizational commitment -- South Africa -- Eastern Cape , Employee morale -- South Africa -- Eastern Cape , Employee loyalty -- South Africa -- Eastern Cape , Employee motivation -- South Africa -- Eastern Cape , Personalism , Small business -- South Africa -- Eastern Cape , Performance -- Management
- Description: This study investigates the impact of motivations, personal values and managerial skills of managers on the performance of Small and medium enterprises (SMEs) in South Africa. The failure rate of SMEs in South Africa is very high and it is of great importance to investigate the factors that can impact on the performance of SMEs. Financial and non-financial methods were used to measure SMEs performance. Data was collected through self-administered questionnaires. Exploratory factor analysis was used to improve the research problems and enhance the validity of the research. Data analysis for this study includes descriptive statistics, Pearson correlation and regression analysis. Reliability was tested using the Cronbach‟s Alpha while validity was ensured by using a statistician and by pre-testing the research instrument in a pilot study.
- Full Text:
- Date Issued: 2012
- Authors: Tangwo, Asah Francis
- Date: 2012
- Subjects: Executives -- South Africa -- Eastern Cape , Labor turnover -- South Africa -- Eastern Cape , Organizational commitment -- South Africa -- Eastern Cape , Employee morale -- South Africa -- Eastern Cape , Employee loyalty -- South Africa -- Eastern Cape , Employee motivation -- South Africa -- Eastern Cape , Personalism , Small business -- South Africa -- Eastern Cape , Performance -- Management
- Language: English
- Type: Thesis , Masters , M Com (Business Management)
- Identifier: vital:11320 , http://hdl.handle.net/10353/d1007046 , Executives -- South Africa -- Eastern Cape , Labor turnover -- South Africa -- Eastern Cape , Organizational commitment -- South Africa -- Eastern Cape , Employee morale -- South Africa -- Eastern Cape , Employee loyalty -- South Africa -- Eastern Cape , Employee motivation -- South Africa -- Eastern Cape , Personalism , Small business -- South Africa -- Eastern Cape , Performance -- Management
- Description: This study investigates the impact of motivations, personal values and managerial skills of managers on the performance of Small and medium enterprises (SMEs) in South Africa. The failure rate of SMEs in South Africa is very high and it is of great importance to investigate the factors that can impact on the performance of SMEs. Financial and non-financial methods were used to measure SMEs performance. Data was collected through self-administered questionnaires. Exploratory factor analysis was used to improve the research problems and enhance the validity of the research. Data analysis for this study includes descriptive statistics, Pearson correlation and regression analysis. Reliability was tested using the Cronbach‟s Alpha while validity was ensured by using a statistician and by pre-testing the research instrument in a pilot study.
- Full Text:
- Date Issued: 2012
Genotypic and phenotypic characterization of enterococci from cow dung and environmental water sources in three selected dairy farms in Amathole District
- Authors: Tanih, Godfred Ngu
- Date: 2016
- Subjects: Enterobacteriaceae Water -- Microbiology Enterococcus faecalis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2348 , vital:27755
- Description: Enterococcus species are integral members of the gastrointestinal microfloral of humans, animals, birds, as well as insects. Their presence in water and food has been greatly associated with faecal contamination. This study was aimed at evaluating the incidence of Enterococcus species in cow dung and environmental water sources in three commercial dairy farms. In addition, their antibiotic profiles were determined as well as resistance and virulence genes. Furthermore, the genetic relatedness of the isolates was determined by molecular typing method (RAPD PCR). Three hundred and thirty four water and faecal samples consisting of 117, 116 and 101 were collected from Seven Star Middle Drift and Fort Hare Dairy trusts respectively. Of the 334 samples collected, 289 were of faecal origin and 45 from water sources within the farms. All samples were screened for enterococci using culture base growth media and molecular methods targeting the tuf gene. Speciation was done using species-specific primers and the incidences of various species within the farms determined. Furthermore resistance to antibiotics and multidrug-resistant phenotypes were established using the disk diffusion method. Genes coding for virulence and resistance were also determined. From the samples collected, 313 (289 faecal and 24 water) presumptive enteroccocci were isolated, 305 of 313 (97.45 percent) were confirmed as Enterococcus of which 239 of 305 (78.38 percent) were identified as E. hirae, 15 of 305 (4.92 percent) as E. faecium, 12/305 (3.93 percent) as E. durans, 6 of 305 (1.97 percent) as E. faecalis and 33 of 305 (10.82 percent) were unidentified. Out of the five virulence genes that were targeted in the study only gelE (71.80 percent of 219/305) and ace (27.2 percent 83/305) were present in the isolates. Phenotypic resistance to antibiotics was observed is in all twelve antibiotics tested with multidrug resistance phenotypes detected in some enterococcal isolates most predominant in Seven Star and Middledrift dairy trust. Finally RAPD profiles of the isolates showed high relatedness between the strains from water and cow dung sources in all three commercial dairy farms suggesting possible contamination from cow dung to the water sources or vice versa.
- Full Text:
- Date Issued: 2016
- Authors: Tanih, Godfred Ngu
- Date: 2016
- Subjects: Enterobacteriaceae Water -- Microbiology Enterococcus faecalis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2348 , vital:27755
- Description: Enterococcus species are integral members of the gastrointestinal microfloral of humans, animals, birds, as well as insects. Their presence in water and food has been greatly associated with faecal contamination. This study was aimed at evaluating the incidence of Enterococcus species in cow dung and environmental water sources in three commercial dairy farms. In addition, their antibiotic profiles were determined as well as resistance and virulence genes. Furthermore, the genetic relatedness of the isolates was determined by molecular typing method (RAPD PCR). Three hundred and thirty four water and faecal samples consisting of 117, 116 and 101 were collected from Seven Star Middle Drift and Fort Hare Dairy trusts respectively. Of the 334 samples collected, 289 were of faecal origin and 45 from water sources within the farms. All samples were screened for enterococci using culture base growth media and molecular methods targeting the tuf gene. Speciation was done using species-specific primers and the incidences of various species within the farms determined. Furthermore resistance to antibiotics and multidrug-resistant phenotypes were established using the disk diffusion method. Genes coding for virulence and resistance were also determined. From the samples collected, 313 (289 faecal and 24 water) presumptive enteroccocci were isolated, 305 of 313 (97.45 percent) were confirmed as Enterococcus of which 239 of 305 (78.38 percent) were identified as E. hirae, 15 of 305 (4.92 percent) as E. faecium, 12/305 (3.93 percent) as E. durans, 6 of 305 (1.97 percent) as E. faecalis and 33 of 305 (10.82 percent) were unidentified. Out of the five virulence genes that were targeted in the study only gelE (71.80 percent of 219/305) and ace (27.2 percent 83/305) were present in the isolates. Phenotypic resistance to antibiotics was observed is in all twelve antibiotics tested with multidrug resistance phenotypes detected in some enterococcal isolates most predominant in Seven Star and Middledrift dairy trust. Finally RAPD profiles of the isolates showed high relatedness between the strains from water and cow dung sources in all three commercial dairy farms suggesting possible contamination from cow dung to the water sources or vice versa.
- Full Text:
- Date Issued: 2016
The Late Cenozoic history and palaeoenvironments of the coastal margin of the south-western Cape Province, South Africa
- Tankard, Anthony James Tempest
- Authors: Tankard, Anthony James Tempest
- Date: 1976
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21068 , http://hdl.handle.net/10962/6257
- Description: This thesis examines the Late Cenozoic history and palaeoenvironments of the coastal margin between Elands Bay on the west coast and Die Kelders on the south coast. This study is introduced with a detailed discussion of eustatic sea level oscillation. The history of the existing ice sheets, sea floor spreading, isotopic composition changes of the oceans, and isostatic responses of the crust to varying loads are reviewed with regard to their bearing on sea level changes. A detailed account of the Neogene stratigraphy of the south-western Cape Province is presented. The Middle to early Late Miocene Saldanha Formation is characterised by shallow marine phosphatic sandstone and phosphorite. It is thought to have been deposited in a warm transgressive sea. The Pliocene Varswater Formation was deposited during a secondary transgression induced by.seaward tilting of the coastal margin during a time of worldwide regression. The Varswater Formation is characterised by pelletal phosphorites. It includes marine, estuarine, and fluvial facies. The estuarine sands and peats contain a rich fossil mammal fauna. Depositional environments of the Pelletal Phosphorite Member are examined by means of conventional grain size analysis to show that deposition took place on a shallow sublittoral platform dominated on the outer edge by a breaker-bar. Accretion of the breaker-bar to form a barrier-island allowed the development of an estuarine complex on the leeward side. Post-depositional diagenetic changes were examined by means of scanning electron microscopy. A detailed account of the petrology and geochemistry of the phosphorite and pelletal phosphorite is presented. The apatite mineral is a carbonate fluorapatite. It is concluded that the phosphorite is related to upwelling of phosphorus-rich waters.
- Full Text:
- Date Issued: 1976
- Authors: Tankard, Anthony James Tempest
- Date: 1976
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:21068 , http://hdl.handle.net/10962/6257
- Description: This thesis examines the Late Cenozoic history and palaeoenvironments of the coastal margin between Elands Bay on the west coast and Die Kelders on the south coast. This study is introduced with a detailed discussion of eustatic sea level oscillation. The history of the existing ice sheets, sea floor spreading, isotopic composition changes of the oceans, and isostatic responses of the crust to varying loads are reviewed with regard to their bearing on sea level changes. A detailed account of the Neogene stratigraphy of the south-western Cape Province is presented. The Middle to early Late Miocene Saldanha Formation is characterised by shallow marine phosphatic sandstone and phosphorite. It is thought to have been deposited in a warm transgressive sea. The Pliocene Varswater Formation was deposited during a secondary transgression induced by.seaward tilting of the coastal margin during a time of worldwide regression. The Varswater Formation is characterised by pelletal phosphorites. It includes marine, estuarine, and fluvial facies. The estuarine sands and peats contain a rich fossil mammal fauna. Depositional environments of the Pelletal Phosphorite Member are examined by means of conventional grain size analysis to show that deposition took place on a shallow sublittoral platform dominated on the outer edge by a breaker-bar. Accretion of the breaker-bar to form a barrier-island allowed the development of an estuarine complex on the leeward side. Post-depositional diagenetic changes were examined by means of scanning electron microscopy. A detailed account of the petrology and geochemistry of the phosphorite and pelletal phosphorite is presented. The apatite mineral is a carbonate fluorapatite. It is concluded that the phosphorite is related to upwelling of phosphorus-rich waters.
- Full Text:
- Date Issued: 1976
East London: the creation and development of a frontier community, 1835-1873
- Tankard, Keith Peter Tempest
- Authors: Tankard, Keith Peter Tempest
- Date: 1985
- Subjects: East London (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2580 , http://hdl.handle.net/10962/d1004550 , East London (South Africa) -- History
- Description: From Preface: Although East London exists today as one of the major ports of South Africa, the city appears to have been forgotten by historians. Little has been done to chronicle its history. In 1932, Bruce Gordon set out to initiate this research and he investigated East London's history to the end of 1865. However, Gordon's thesis, though accurate, is short and inadequate by today's standards. Furthermore, no-one continued from where Gordon left off. Several articles have been written over the previous six decades, each dealing with aspects of East London's past but these, on the whole, are inaccurate and misleading. The time is ripe, therefore, to begin again the research into the history of East London. East London owed its foundation to the state of unrest which existed on the eastern frontier of the Cape of Good Hope between 1834 and 1847. Although the geographic and climatic conditions were in the port's favour, East London remained in a suppressed condition until about 1870. It is the purpose of this thesis to examine the factors which gave rise to this truncated growth. The thesis will examine first the wider perspective of imperial and colonial policy in which East London was conceived and in which it had its early existence. The implications of this policy for East London at the various levels of the port's development will be explored in subsequent chapters. British and Cape colonial policy, however, evolved in a chronological sequence and so the examination of this policy likewise will tend to follow a chronological pattern within each chapter. The establishment of Port Rex in November/December 1836 enters into East London's story in several ways: its political development, the creation and development of the harbour on the Buffalo River, the evolution of trade, the growth of the community and the status of the black population at the mouth of the Buffalo River. It has been found necessary, therefore, to refer often to this beginning of East London's history. Although several theses have already been written which deal with topics related to British Kaffraria, none of these do more than allude to the creation and development of East London. Although, for example, the German Settlers played an important role in the growth of the port, Schnell's thesis hardly mentions the two communities at Panmure and Cambridge. The research for this thesis led me to two important and little known sources of early information, both in Cape Town. The first was the multiple volumed "Unsorted Archives" on East London which consists of reports and letters to the Resident Magistrate. It is a treasure chest of information on East London's early years. The second source was G.M. Theal's newspapers, The Kaffrarian Recorder and East London Shipping Gazette and, later, The Kaffrarian, East London's second newspaper which was believed to have been lost until copies were discovered recently in the South African Library in Cape Town. Theal, later prominent as a historian, had a clear insight into the problems which confronted the community at East London and the editorials of his newspaper make interesting reading. East London's first newspaper is, unfortunately, still lost. It was the East London Times which had its first issue in January 1863, and lasted a mere two months. It consisted of half a sheet of foolscap printed on one side, the other side being left blank, the editor of the King William's Town Gazette wrote, "'for want of room' or from lack of matter."
- Full Text:
- Date Issued: 1985
- Authors: Tankard, Keith Peter Tempest
- Date: 1985
- Subjects: East London (South Africa) -- History
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2580 , http://hdl.handle.net/10962/d1004550 , East London (South Africa) -- History
- Description: From Preface: Although East London exists today as one of the major ports of South Africa, the city appears to have been forgotten by historians. Little has been done to chronicle its history. In 1932, Bruce Gordon set out to initiate this research and he investigated East London's history to the end of 1865. However, Gordon's thesis, though accurate, is short and inadequate by today's standards. Furthermore, no-one continued from where Gordon left off. Several articles have been written over the previous six decades, each dealing with aspects of East London's past but these, on the whole, are inaccurate and misleading. The time is ripe, therefore, to begin again the research into the history of East London. East London owed its foundation to the state of unrest which existed on the eastern frontier of the Cape of Good Hope between 1834 and 1847. Although the geographic and climatic conditions were in the port's favour, East London remained in a suppressed condition until about 1870. It is the purpose of this thesis to examine the factors which gave rise to this truncated growth. The thesis will examine first the wider perspective of imperial and colonial policy in which East London was conceived and in which it had its early existence. The implications of this policy for East London at the various levels of the port's development will be explored in subsequent chapters. British and Cape colonial policy, however, evolved in a chronological sequence and so the examination of this policy likewise will tend to follow a chronological pattern within each chapter. The establishment of Port Rex in November/December 1836 enters into East London's story in several ways: its political development, the creation and development of the harbour on the Buffalo River, the evolution of trade, the growth of the community and the status of the black population at the mouth of the Buffalo River. It has been found necessary, therefore, to refer often to this beginning of East London's history. Although several theses have already been written which deal with topics related to British Kaffraria, none of these do more than allude to the creation and development of East London. Although, for example, the German Settlers played an important role in the growth of the port, Schnell's thesis hardly mentions the two communities at Panmure and Cambridge. The research for this thesis led me to two important and little known sources of early information, both in Cape Town. The first was the multiple volumed "Unsorted Archives" on East London which consists of reports and letters to the Resident Magistrate. It is a treasure chest of information on East London's early years. The second source was G.M. Theal's newspapers, The Kaffrarian Recorder and East London Shipping Gazette and, later, The Kaffrarian, East London's second newspaper which was believed to have been lost until copies were discovered recently in the South African Library in Cape Town. Theal, later prominent as a historian, had a clear insight into the problems which confronted the community at East London and the editorials of his newspaper make interesting reading. East London's first newspaper is, unfortunately, still lost. It was the East London Times which had its first issue in January 1863, and lasted a mere two months. It consisted of half a sheet of foolscap printed on one side, the other side being left blank, the editor of the King William's Town Gazette wrote, "'for want of room' or from lack of matter."
- Full Text:
- Date Issued: 1985
The development of East London through four decades of municipal control, 1873-1914
- Tankard, Keith Peter Tempest
- Authors: Tankard, Keith Peter Tempest
- Date: 1991
- Subjects: East London (South Africa) -- History , East London (South Africa) -- Economic conditions , East London (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2560 , http://hdl.handle.net/10962/d1002413 , East London (South Africa) -- History , East London (South Africa) -- Economic conditions , East London (South Africa) -- Social conditions
- Description: This thesis is a study in Urban History which explores the development of East London, a port in the Border region of the Eastern Cape, South Africa, through four decades of municipal control from 1873 to 1914. The town had been established in 1847 as a supply route for the British forces during the War of the Axe (7th Frontier War) but the frontier nature of the port led to economic and physical stagnation during its initial 25 years of existence. Indeed, by the time that the municipality was established in 1873, there were still no streets beyond cart tracks, no established water supply, and sanitary conditions were medieval. The Town Council therefore had much to occupy its attention but lack of positive leadership resulted in failure to capitalise on prosperous economic conditions, while a depression in the 1880's led to a further truncation of growth. It was only in the 1890's that a combination of economic growth and vibrant leadership brought about rapid civic advance, with large-scale expenditure on street construction, as well as the establishment of electricity and a tramway system. The outbreak of the Anglo-Boer War in 1899 slowed progress, however, and a post-war depression placed renewed stress on the municipality. The thesis examines the progress of the town on a broad front, dealing with the issues of economic fluctuations, the growth of the harbour as the heart of the trading sector, the physical advance of the municipality, the search for a viable water supply, the evolution of public health and sanitation, and the establishment of the port as a coastal resort. In addition, it studies the conflict of social attitudes among the townspeople, the evolution of racial segregation, and the effects of the Anglo-Boer War on the town, with the influx of some 5 000 Uitlander refugees and the establishment of a Boer concentration camp. A final chapter attempts an analysis of the reasons behind the Town Council's inability to make the best use of its opportunities to foster the development of East London.
- Full Text:
- Date Issued: 1991
- Authors: Tankard, Keith Peter Tempest
- Date: 1991
- Subjects: East London (South Africa) -- History , East London (South Africa) -- Economic conditions , East London (South Africa) -- Social conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2560 , http://hdl.handle.net/10962/d1002413 , East London (South Africa) -- History , East London (South Africa) -- Economic conditions , East London (South Africa) -- Social conditions
- Description: This thesis is a study in Urban History which explores the development of East London, a port in the Border region of the Eastern Cape, South Africa, through four decades of municipal control from 1873 to 1914. The town had been established in 1847 as a supply route for the British forces during the War of the Axe (7th Frontier War) but the frontier nature of the port led to economic and physical stagnation during its initial 25 years of existence. Indeed, by the time that the municipality was established in 1873, there were still no streets beyond cart tracks, no established water supply, and sanitary conditions were medieval. The Town Council therefore had much to occupy its attention but lack of positive leadership resulted in failure to capitalise on prosperous economic conditions, while a depression in the 1880's led to a further truncation of growth. It was only in the 1890's that a combination of economic growth and vibrant leadership brought about rapid civic advance, with large-scale expenditure on street construction, as well as the establishment of electricity and a tramway system. The outbreak of the Anglo-Boer War in 1899 slowed progress, however, and a post-war depression placed renewed stress on the municipality. The thesis examines the progress of the town on a broad front, dealing with the issues of economic fluctuations, the growth of the harbour as the heart of the trading sector, the physical advance of the municipality, the search for a viable water supply, the evolution of public health and sanitation, and the establishment of the port as a coastal resort. In addition, it studies the conflict of social attitudes among the townspeople, the evolution of racial segregation, and the effects of the Anglo-Boer War on the town, with the influx of some 5 000 Uitlander refugees and the establishment of a Boer concentration camp. A final chapter attempts an analysis of the reasons behind the Town Council's inability to make the best use of its opportunities to foster the development of East London.
- Full Text:
- Date Issued: 1991
Over-expression, purification and biochemical characterization of DOXP reductoisomerase and the rational design of novel anti-malarial drugs
- Authors: Tanner, Delia Caroline
- Date: 2004
- Subjects: Malaria -- Prevention , Malaria -- Drug therapy , Antimalarials -- Therapeutic use , Proteins -- Purification , Amino acids -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3931 , http://hdl.handle.net/10962/d1003990 , Malaria -- Prevention , Malaria -- Drug therapy , Antimalarials -- Therapeutic use , Proteins -- Purification , Amino acids -- Analysis
- Description: Malaria poses the greatest threat of all parasites to human life. Current vaccines and efficacious drugs are available however their use is limited due to toxicity, emergence of drug resistance, and cost. The discovery of an alternative pathway of isoprenoid biosynthesis, the non-mevalonate pathway, within the malarial parasite has resulted in development of novel anti-malarial drugs. 1-Deoxy-D-xylulose-5-phosphate (DOXP) reductoisomerase, the second enzyme in this pathway, is responsible for the synthesis of 2-C-methyl-D-erythritol 4-phosphate (MEP) in an intramolecular rearrangement step followed by a reduction process involving NADPH as a hydrogen donor and divalent cations as co-factors. Fosmidomycin and FR900098 have been identified as inhibitors of DOXP reductoisomerase. However, they lack clinical efficacy. In this investigation recombinant DOXP reductoisomerase from Escherichia coli (EcDXR) and Plasmodium falciparum (pfDXR) were biochemically characterized as potential targets for inhibition. (His)6-EcDXR was successfully purified using nickel-chelate affinity chromatography with a specific activity of 1.77 μmoles/min/mg and Km value 282 μM. Utilizing multiple sequence alignment, previous structural data predictions and homology modeling approaches, critical active site amino acid residues were identified and their role in the catalytic activity investigated utilizing site-directed mutagenesis techniques. We have shown evidence that suggests that Trp212 and Met214 interact to maintain the active site architecture and hydrophobic interactions necessary for substrate binding, cofactor binding and enzyme activity. Replacement of Trp212 with Tyr, Phe, and Leu reduced specific activity relative to EcDXR. EcDXR(W212F) and EcDXR(W212Y) had an increased Km relative to EcDXR indicative of loss in affinity toward DOXP, whereas EcDXR(W212L) had a lower Km of ~8 μM indicative of increased affinity for DOXP. The W212L substitution possibly removed contacts necessary for full catalytic activity, but could be considered a non-disruptive substitution in that it maintained active site architecture sufficient for DOXP reductoisomerase activity. EcDXR(M214I) had 36-fold reduced enzyme activity relative to EcDXR, while its Km (~8 μM) was found to be lower than that of EcDXR. This suggested that the M214I substitution had maintained (perhaps improved) substrate and active site architecture, but may have perturbed interactions with NADPH. Rational drug design strategies and docking methods have been utilized in the development of furan derivatives as DOXP reductoisomerase inhibitors, and the synthesis of phosphorylated derivatives (5) and (6) has been achieved. Future inhibitor studies using these novel potential DOXP reductoisomerase inhibitors may lead to the development of effective anti-malarial drug candidates.
- Full Text:
- Date Issued: 2004
- Authors: Tanner, Delia Caroline
- Date: 2004
- Subjects: Malaria -- Prevention , Malaria -- Drug therapy , Antimalarials -- Therapeutic use , Proteins -- Purification , Amino acids -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3931 , http://hdl.handle.net/10962/d1003990 , Malaria -- Prevention , Malaria -- Drug therapy , Antimalarials -- Therapeutic use , Proteins -- Purification , Amino acids -- Analysis
- Description: Malaria poses the greatest threat of all parasites to human life. Current vaccines and efficacious drugs are available however their use is limited due to toxicity, emergence of drug resistance, and cost. The discovery of an alternative pathway of isoprenoid biosynthesis, the non-mevalonate pathway, within the malarial parasite has resulted in development of novel anti-malarial drugs. 1-Deoxy-D-xylulose-5-phosphate (DOXP) reductoisomerase, the second enzyme in this pathway, is responsible for the synthesis of 2-C-methyl-D-erythritol 4-phosphate (MEP) in an intramolecular rearrangement step followed by a reduction process involving NADPH as a hydrogen donor and divalent cations as co-factors. Fosmidomycin and FR900098 have been identified as inhibitors of DOXP reductoisomerase. However, they lack clinical efficacy. In this investigation recombinant DOXP reductoisomerase from Escherichia coli (EcDXR) and Plasmodium falciparum (pfDXR) were biochemically characterized as potential targets for inhibition. (His)6-EcDXR was successfully purified using nickel-chelate affinity chromatography with a specific activity of 1.77 μmoles/min/mg and Km value 282 μM. Utilizing multiple sequence alignment, previous structural data predictions and homology modeling approaches, critical active site amino acid residues were identified and their role in the catalytic activity investigated utilizing site-directed mutagenesis techniques. We have shown evidence that suggests that Trp212 and Met214 interact to maintain the active site architecture and hydrophobic interactions necessary for substrate binding, cofactor binding and enzyme activity. Replacement of Trp212 with Tyr, Phe, and Leu reduced specific activity relative to EcDXR. EcDXR(W212F) and EcDXR(W212Y) had an increased Km relative to EcDXR indicative of loss in affinity toward DOXP, whereas EcDXR(W212L) had a lower Km of ~8 μM indicative of increased affinity for DOXP. The W212L substitution possibly removed contacts necessary for full catalytic activity, but could be considered a non-disruptive substitution in that it maintained active site architecture sufficient for DOXP reductoisomerase activity. EcDXR(M214I) had 36-fold reduced enzyme activity relative to EcDXR, while its Km (~8 μM) was found to be lower than that of EcDXR. This suggested that the M214I substitution had maintained (perhaps improved) substrate and active site architecture, but may have perturbed interactions with NADPH. Rational drug design strategies and docking methods have been utilized in the development of furan derivatives as DOXP reductoisomerase inhibitors, and the synthesis of phosphorylated derivatives (5) and (6) has been achieved. Future inhibitor studies using these novel potential DOXP reductoisomerase inhibitors may lead to the development of effective anti-malarial drug candidates.
- Full Text:
- Date Issued: 2004
Understanding and modelling of surface and groundwater interactions
- Authors: Tanner, Jane Louise
- Date: 2014
- Subjects: Groundwater -- South Africa , Water-supply -- Management , Integrated water development , Hydrogeology , Water resources development -- South Africa , Water -- Analysis , Groundwater -- Management , Watersheds -- South Africa , Hydrologic models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6043 , http://hdl.handle.net/10962/d1012994
- Description: The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental to effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilised, and especially in those regions that suffer problems of data scarcity. This study explores some of the principle issues associated with understanding and practically modelling surface and groundwater interactions. In South Africa, there remains much controversy over the most appropriate type of integrated model to be used and the way forward in terms of the development of the discipline; part of the disagreement stems from the fact that we cannot validate models adequately. This is largely due to traditional forms of model testing having limited power as it is difficult to differentiate between the uncertainties within different model structures, different sets of alternative parameter values and in the input data used to run the model. While model structural uncertainties are important to consider, the uncertainty from input data error together with parameter estimation error are often more significant to the overall residual error, and essential to consider if we want to achieve reliable predictions for water resource decisions. While new philosophies and theories on modelling and results validation have been developed (Beven, 2002; Gupta et al., 2008), in many cases models are not only still being validated and compared using sparse and uncertain datasets, but also expected to produce reliable predictions based on the flawed data. The approach in this study is focused on fundamental understanding of hydrological systems rather than calibration based modelling and promotes the use of all the available 'hard' and 'soft' data together with thoughtful conceptual examination of the processes occurring in an environment to ensure as far as possible that a model is generating sensible results by simulating the correct processes. The first part of the thesis focuses on characterising the 'typical' interaction environments found in South Africa. It was found that many traditional perceptual models are not necessarily applicable to South African conditions, largely due to the relative importance of unsaturated zone processes and the complexity of the dominantly fractured rock environments. The interaction environments were categorised into four main 'types' of environment. These include karst, primary, fractured rock (secondary), and alluvial environments. Processes critical to Integrated Water Resource Management (IWRM) were defined within each interaction type as a guideline to setting a model up to realistically represent the dominant processes in the respective settings. The second part of the thesis addressed the application and evaluation of the modified Pitman model (Hughes, 2004), which allows for surface and groundwater interaction behaviour at the catchment scale to be simulated. The issue is whether, given the different sources of uncertainty in the modelling process, we can differentiate one conceptual flow path from another in trying to refine the understanding and consequently have more faith in model predictions. Seven example catchments were selected from around South Africa to assess whether reliable integrated assessments can be carried out given the existing data. Specific catchment perceptual models were used to identify the critical processes occurring in each setting and the Pitman model was assessed on whether it could represent them (structural uncertainty). The available knowledge of specific environments or catchments was then examined in an attempt to resolve the parameter uncertainty present within each catchment and ensure the subsequent model setup was correctly representing the process understanding as far as possible. The confidence in the quantitative results inevitably varied with the amount and quality of the data available. While the model was deemed to be robust based on the behavioural results obtained in the majority of the case studies, in many cases a quantitative validation of the outputs was just not possible based on the available data. In these cases, the model was judged on its ability to represent the conceptualisation of the processes occurring in the catchments. While the lack of appropriate data means there will always be considerable uncertainty surrounding model validation, it can be argued that improved process understanding in an environment can be used to validate model outcomes to a degree, by assessing whether a model is getting the right results for the right reasons. Many water resource decisions are still made without adequate account being taken of the uncertainties inherent in assessing the response of hydrological systems. Certainly, with all the possible sources of uncertainty in a data scarce country such as South Africa, pure calibration based modelling is unlikely to produce reliable information for water resource managers as it can produce the right results for the wrong reasons. Thus it becomes essential to incorporate conceptual thinking into the modelling process, so that at the very least we are able to conclude that a model generates estimates that are consistent with, and reflect, our understanding (however limited) of the catchment processes. It is fairly clear that achieving the optimum model of a hydrological system may be fraught with difficulty, if not impossible. This makes it very difficult from a practitioner's point of view to decide which model and uncertainty estimation method to use. According to Beven (2009), this may be a transitional problem and in the future it may become clearer as we learn more about how to estimate the uncertainties associated with hydrological systems. Until then, a better understanding of the fundamental and most critical hydrogeological processes should be used to critically test and improve model predictions as far as possible. A major focus of the study was to identify whether the modified Pitman model could provide a practical tool for water resource managers by reliably determining the available water resource. The incorporation of surface and groundwater interaction routines seems to have resulted in a more robust and realistic model of basin hydrology. The overall conclusion is that the model, although simplified, is capable of representing the catchment scale processes that occur under most South African conditions.
- Full Text:
- Date Issued: 2014
- Authors: Tanner, Jane Louise
- Date: 2014
- Subjects: Groundwater -- South Africa , Water-supply -- Management , Integrated water development , Hydrogeology , Water resources development -- South Africa , Water -- Analysis , Groundwater -- Management , Watersheds -- South Africa , Hydrologic models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6043 , http://hdl.handle.net/10962/d1012994
- Description: The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental to effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilised, and especially in those regions that suffer problems of data scarcity. This study explores some of the principle issues associated with understanding and practically modelling surface and groundwater interactions. In South Africa, there remains much controversy over the most appropriate type of integrated model to be used and the way forward in terms of the development of the discipline; part of the disagreement stems from the fact that we cannot validate models adequately. This is largely due to traditional forms of model testing having limited power as it is difficult to differentiate between the uncertainties within different model structures, different sets of alternative parameter values and in the input data used to run the model. While model structural uncertainties are important to consider, the uncertainty from input data error together with parameter estimation error are often more significant to the overall residual error, and essential to consider if we want to achieve reliable predictions for water resource decisions. While new philosophies and theories on modelling and results validation have been developed (Beven, 2002; Gupta et al., 2008), in many cases models are not only still being validated and compared using sparse and uncertain datasets, but also expected to produce reliable predictions based on the flawed data. The approach in this study is focused on fundamental understanding of hydrological systems rather than calibration based modelling and promotes the use of all the available 'hard' and 'soft' data together with thoughtful conceptual examination of the processes occurring in an environment to ensure as far as possible that a model is generating sensible results by simulating the correct processes. The first part of the thesis focuses on characterising the 'typical' interaction environments found in South Africa. It was found that many traditional perceptual models are not necessarily applicable to South African conditions, largely due to the relative importance of unsaturated zone processes and the complexity of the dominantly fractured rock environments. The interaction environments were categorised into four main 'types' of environment. These include karst, primary, fractured rock (secondary), and alluvial environments. Processes critical to Integrated Water Resource Management (IWRM) were defined within each interaction type as a guideline to setting a model up to realistically represent the dominant processes in the respective settings. The second part of the thesis addressed the application and evaluation of the modified Pitman model (Hughes, 2004), which allows for surface and groundwater interaction behaviour at the catchment scale to be simulated. The issue is whether, given the different sources of uncertainty in the modelling process, we can differentiate one conceptual flow path from another in trying to refine the understanding and consequently have more faith in model predictions. Seven example catchments were selected from around South Africa to assess whether reliable integrated assessments can be carried out given the existing data. Specific catchment perceptual models were used to identify the critical processes occurring in each setting and the Pitman model was assessed on whether it could represent them (structural uncertainty). The available knowledge of specific environments or catchments was then examined in an attempt to resolve the parameter uncertainty present within each catchment and ensure the subsequent model setup was correctly representing the process understanding as far as possible. The confidence in the quantitative results inevitably varied with the amount and quality of the data available. While the model was deemed to be robust based on the behavioural results obtained in the majority of the case studies, in many cases a quantitative validation of the outputs was just not possible based on the available data. In these cases, the model was judged on its ability to represent the conceptualisation of the processes occurring in the catchments. While the lack of appropriate data means there will always be considerable uncertainty surrounding model validation, it can be argued that improved process understanding in an environment can be used to validate model outcomes to a degree, by assessing whether a model is getting the right results for the right reasons. Many water resource decisions are still made without adequate account being taken of the uncertainties inherent in assessing the response of hydrological systems. Certainly, with all the possible sources of uncertainty in a data scarce country such as South Africa, pure calibration based modelling is unlikely to produce reliable information for water resource managers as it can produce the right results for the wrong reasons. Thus it becomes essential to incorporate conceptual thinking into the modelling process, so that at the very least we are able to conclude that a model generates estimates that are consistent with, and reflect, our understanding (however limited) of the catchment processes. It is fairly clear that achieving the optimum model of a hydrological system may be fraught with difficulty, if not impossible. This makes it very difficult from a practitioner's point of view to decide which model and uncertainty estimation method to use. According to Beven (2009), this may be a transitional problem and in the future it may become clearer as we learn more about how to estimate the uncertainties associated with hydrological systems. Until then, a better understanding of the fundamental and most critical hydrogeological processes should be used to critically test and improve model predictions as far as possible. A major focus of the study was to identify whether the modified Pitman model could provide a practical tool for water resource managers by reliably determining the available water resource. The incorporation of surface and groundwater interaction routines seems to have resulted in a more robust and realistic model of basin hydrology. The overall conclusion is that the model, although simplified, is capable of representing the catchment scale processes that occur under most South African conditions.
- Full Text:
- Date Issued: 2014
The application of a landscape diversity index using remote sensing and geographical information systems to identify degradation patterns in the Great Fish River Valley, Eastern Cape Province, South Africa
- Authors: Tanser, Frank Courteney
- Date: 1997
- Subjects: Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4814 , http://hdl.handle.net/10962/d1005488 , Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Description: Using a range of satellite-derived indices I describe. monitor and predict vegetation conditions that exist in the Great Fish River Valley, Eastern Cape. The heterogeneous nature of the area necessitates that the mapping of vegetation classes be accomplished using a combination of a supervised approach, an unsupervised approach and the use of a Moving Standard Deviation Index (MSDI). Nine vegetation classes are identified and mapped at an accuracy of 84%. The vegetation classes are strongly related to land-use and the communal areas demonstrate a reduction in palatable species and a shift towards dominance by a single species. Nature reserves and commercial rangeland are by contrast dominated by good condition vegetation types. The Modified Soil Adjusted Vegetation Index (MSA VI) is used to map the vegetation production in the study area. The influence of soil reflectance is reduced using this index. The MSA VI proves to be a good predictor of vegetation condition in the higher rainfall areas but not in the more semi-arid regions. The MSA VI has a significant relationship to rainfall but no absolute relationship to biomass. However, a stratification approach (on the basis of vegetation type) reveals that the MSA VI exhibits relationships to biomass in vegetation types occurring in the higher rainfall areas and consisting of a large cover of shrubs. A technique based on an index which describes landscape spatial variability is presented to assist in the interpretation of landscape condition. The research outlines a method for degradation assessment which overcomes many of the problems associated with cost and repeatability. Indices that attempt to provide a correlation with net primary productivity, e.g. NDVI, do not consider changes in the quality of net primary productivity. Landscape variability represents a measure of ecosystem change in the landscape that underlies the degradation process. The hypothesis is that healthy/undisturbed/stable landscapes tend to be less variable and homogenous than their degraded heterogenous counterparts. The Moving Standard Deviation Index (MSDI) is calculated by performing a 3 x 3 moving standard deviation window across Landsat Thematic Mapper (TM) band 3. The result is a sensitive indicator of landscape condition which is not affected by moisture availability and vegetation type. The MSDI shows a significant negative relationship to NDVI confirming its relationship to condition. The cross-classification of MSDI with NDVI allows the identification of invasive woody weeds which exhibit strong photosynthetic signals and would therefore be categorised as good condition using NDVI. Other ecosystems are investigated to determine the relationship between NDVI and MSDI. Where increase in NDVI is disturbance-induced (such as the Kalahari Desert) the relationship is positive. Where high NDVI values are indicative of good condition rangeland (such as the Fish River Valley) the relationship is negative. The MSDI therefore always exhibits a significant positive relationship to degradation irrespective of the relationship of NDVI to condition in the ecosystem.
- Full Text:
- Date Issued: 1997
- Authors: Tanser, Frank Courteney
- Date: 1997
- Subjects: Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4814 , http://hdl.handle.net/10962/d1005488 , Geographic information systems , Earth sciences -- Remote sensing , Environmental degradation -- South Africa -- Eastern Cape -- Great Fish River Valley , Forest degradation -- South Africa -- Eastern Cape -- Great Rish River Valley
- Description: Using a range of satellite-derived indices I describe. monitor and predict vegetation conditions that exist in the Great Fish River Valley, Eastern Cape. The heterogeneous nature of the area necessitates that the mapping of vegetation classes be accomplished using a combination of a supervised approach, an unsupervised approach and the use of a Moving Standard Deviation Index (MSDI). Nine vegetation classes are identified and mapped at an accuracy of 84%. The vegetation classes are strongly related to land-use and the communal areas demonstrate a reduction in palatable species and a shift towards dominance by a single species. Nature reserves and commercial rangeland are by contrast dominated by good condition vegetation types. The Modified Soil Adjusted Vegetation Index (MSA VI) is used to map the vegetation production in the study area. The influence of soil reflectance is reduced using this index. The MSA VI proves to be a good predictor of vegetation condition in the higher rainfall areas but not in the more semi-arid regions. The MSA VI has a significant relationship to rainfall but no absolute relationship to biomass. However, a stratification approach (on the basis of vegetation type) reveals that the MSA VI exhibits relationships to biomass in vegetation types occurring in the higher rainfall areas and consisting of a large cover of shrubs. A technique based on an index which describes landscape spatial variability is presented to assist in the interpretation of landscape condition. The research outlines a method for degradation assessment which overcomes many of the problems associated with cost and repeatability. Indices that attempt to provide a correlation with net primary productivity, e.g. NDVI, do not consider changes in the quality of net primary productivity. Landscape variability represents a measure of ecosystem change in the landscape that underlies the degradation process. The hypothesis is that healthy/undisturbed/stable landscapes tend to be less variable and homogenous than their degraded heterogenous counterparts. The Moving Standard Deviation Index (MSDI) is calculated by performing a 3 x 3 moving standard deviation window across Landsat Thematic Mapper (TM) band 3. The result is a sensitive indicator of landscape condition which is not affected by moisture availability and vegetation type. The MSDI shows a significant negative relationship to NDVI confirming its relationship to condition. The cross-classification of MSDI with NDVI allows the identification of invasive woody weeds which exhibit strong photosynthetic signals and would therefore be categorised as good condition using NDVI. Other ecosystems are investigated to determine the relationship between NDVI and MSDI. Where increase in NDVI is disturbance-induced (such as the Kalahari Desert) the relationship is positive. Where high NDVI values are indicative of good condition rangeland (such as the Fish River Valley) the relationship is negative. The MSDI therefore always exhibits a significant positive relationship to degradation irrespective of the relationship of NDVI to condition in the ecosystem.
- Full Text:
- Date Issued: 1997