Application of CE, HPLC and LC-MS-MS for the analysis and quality control of Ginkgo biloba dosage forms
- Authors: Dubber, Mary-Jean
- Date: 2006
- Subjects: Pharmaceutical chemistry -- Quality control Ginkgo Micelles Capillary electrophoresis High performance liquid chromatography Drugs -- Dosage forms Flavonoids Terpenes Herbals
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3757 , http://hdl.handle.net/10962/d1003235
- Description: Natural products are complex mixtures of compounds with therapeutic effects which are often reported to be due to the synergistic action of multiple and sometimes unknown components. Consequently, standardization of these products is complex and a lack of effective quality control (QC) criteria in most countries has led to marketing of commercial products with questionable quality, safety and efficacy (QSE). The aim of this study was therefore to develop qualitative and quantitative analytical methods for use in the QC of Ginkgo biloba solid oral dosage forms. Initially, a micellar electrokinetic chromatography (MEKC) method was developed for the identification of the flavonol glycosides, rutin and quercitrin as well as 3 flavonol aglycones, quercetin, kaempferol and isorhamnetin in crude extracts of 4 Ginkgo biloba solid oral dosage forms using ultraviolet (UV) detection. A reversed-flow cyclodextrin-modified MEKC method was subsequently developed for the simultaneous determination of the aforementioned flavonols as well as ginkgolide A, B, C, J and bilobalide (all positive markers) in Ginkgo commercial products. A non-aqueous capillary electrophoresis (CE) method was also developed for fingerprinting the presence of ginkgolic acids (negative markers) in Ginkgo biloba leaf extracts, which are purported to be associated with toxic properties. This method was also applied to 2 Ginkgo biloba commercial products. Since the flavonols have strong UV absorbing chromophores, a reversed phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated using photo-diode-array (PDA) detection which was then successfully applied to fingerprint commercially available Ginkgo biloba solid oral dosage forms as well as quantify the relevant flavonol markers present in these extracts. Sample preparation was simple, rapid and cost efficient with minimal clean-up and the employment of a minibore column which requires low mobile phase flow rates contributed to the economy of the method. Unlike the conventional QC approach, samples were not hydrolyzed and direct determination of 2 intact flavonol glycosides, together with the usual aglycone markers was facilitated which provided maximal content information for fingerprint comparisons. On the other hand, terpene trilactones possess poor chromophores and an alternative detection method to UV was required in order to obtain suitable sensitivity. RP-HPLC with evaporative light scattering detection (ELSD) was selected for quantification of these non-volatile constituents in Ginkgo dosage forms and this method was deemed suitable for the routine QC analysis of these positive markers in commercial products. Since approximately 33 flavonoids have been identified in Ginkgo biloba leaf extracts, baseline separation using UV/PDA detection normally requires complex gradient programs and long analysis times. In addition, unequivocal identification of the flavonoids with similar UV spectra and elution times cannot be guaranteed. A liquid chromatographic tandem mass spectrometric (LC-MS-MS) method was therefore developed and validated in order to ensure accurate quantification of the selected flavonol marker compounds in Ginkgo commercial products. LC-MS-MS analysis of Ginkgo extracts revealed, in addition to rutin, the possible presence of other quercetin analogues, quercetin-3-Orhamnoside-7-O-glucoside or quercetin-3-O-glucoside-7-O-rhamnoside, previously unreported in Ginkgo biloba leaf extracts or dosage forms. In terms of evaluating the most suitable analytical method for QC, CE shows exceptional potential in the future analysis of Ginkgo biloba dosage forms while HPLC-PDA and HPLC-ELSD are currently the most affordable and practical instruments for the routine analysis of the flavonols and terpenoids, respectively. LC-MS-MS proved to be pivotal for the accurate identification and quantification of the flavonols due to interference by other flavonoid compounds with similar retention times and UV spectra to the peaks of interest. All quantitative and qualitative results revealed large discrepancies in the marker content between the products regardless of which batch was analysed and product labels disclosed little relevant information. Although currently not required by most regulatory agencies, some of the usual quality criteria applied to orthodox medicines was evaluated. In particular, dissolution analysis, disintegration, tablet hardness and weight uniformity were assessed and revealed similar inconsistencies. This thesis emphasises that implementation of effective QC criteria is long overdue and is essential to ensure consistent product QSE of commercially available Ginkgo biloba solid oral dosage forms.
- Full Text:
- Date Issued: 2006
- Authors: Dubber, Mary-Jean
- Date: 2006
- Subjects: Pharmaceutical chemistry -- Quality control Ginkgo Micelles Capillary electrophoresis High performance liquid chromatography Drugs -- Dosage forms Flavonoids Terpenes Herbals
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3757 , http://hdl.handle.net/10962/d1003235
- Description: Natural products are complex mixtures of compounds with therapeutic effects which are often reported to be due to the synergistic action of multiple and sometimes unknown components. Consequently, standardization of these products is complex and a lack of effective quality control (QC) criteria in most countries has led to marketing of commercial products with questionable quality, safety and efficacy (QSE). The aim of this study was therefore to develop qualitative and quantitative analytical methods for use in the QC of Ginkgo biloba solid oral dosage forms. Initially, a micellar electrokinetic chromatography (MEKC) method was developed for the identification of the flavonol glycosides, rutin and quercitrin as well as 3 flavonol aglycones, quercetin, kaempferol and isorhamnetin in crude extracts of 4 Ginkgo biloba solid oral dosage forms using ultraviolet (UV) detection. A reversed-flow cyclodextrin-modified MEKC method was subsequently developed for the simultaneous determination of the aforementioned flavonols as well as ginkgolide A, B, C, J and bilobalide (all positive markers) in Ginkgo commercial products. A non-aqueous capillary electrophoresis (CE) method was also developed for fingerprinting the presence of ginkgolic acids (negative markers) in Ginkgo biloba leaf extracts, which are purported to be associated with toxic properties. This method was also applied to 2 Ginkgo biloba commercial products. Since the flavonols have strong UV absorbing chromophores, a reversed phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated using photo-diode-array (PDA) detection which was then successfully applied to fingerprint commercially available Ginkgo biloba solid oral dosage forms as well as quantify the relevant flavonol markers present in these extracts. Sample preparation was simple, rapid and cost efficient with minimal clean-up and the employment of a minibore column which requires low mobile phase flow rates contributed to the economy of the method. Unlike the conventional QC approach, samples were not hydrolyzed and direct determination of 2 intact flavonol glycosides, together with the usual aglycone markers was facilitated which provided maximal content information for fingerprint comparisons. On the other hand, terpene trilactones possess poor chromophores and an alternative detection method to UV was required in order to obtain suitable sensitivity. RP-HPLC with evaporative light scattering detection (ELSD) was selected for quantification of these non-volatile constituents in Ginkgo dosage forms and this method was deemed suitable for the routine QC analysis of these positive markers in commercial products. Since approximately 33 flavonoids have been identified in Ginkgo biloba leaf extracts, baseline separation using UV/PDA detection normally requires complex gradient programs and long analysis times. In addition, unequivocal identification of the flavonoids with similar UV spectra and elution times cannot be guaranteed. A liquid chromatographic tandem mass spectrometric (LC-MS-MS) method was therefore developed and validated in order to ensure accurate quantification of the selected flavonol marker compounds in Ginkgo commercial products. LC-MS-MS analysis of Ginkgo extracts revealed, in addition to rutin, the possible presence of other quercetin analogues, quercetin-3-Orhamnoside-7-O-glucoside or quercetin-3-O-glucoside-7-O-rhamnoside, previously unreported in Ginkgo biloba leaf extracts or dosage forms. In terms of evaluating the most suitable analytical method for QC, CE shows exceptional potential in the future analysis of Ginkgo biloba dosage forms while HPLC-PDA and HPLC-ELSD are currently the most affordable and practical instruments for the routine analysis of the flavonols and terpenoids, respectively. LC-MS-MS proved to be pivotal for the accurate identification and quantification of the flavonols due to interference by other flavonoid compounds with similar retention times and UV spectra to the peaks of interest. All quantitative and qualitative results revealed large discrepancies in the marker content between the products regardless of which batch was analysed and product labels disclosed little relevant information. Although currently not required by most regulatory agencies, some of the usual quality criteria applied to orthodox medicines was evaluated. In particular, dissolution analysis, disintegration, tablet hardness and weight uniformity were assessed and revealed similar inconsistencies. This thesis emphasises that implementation of effective QC criteria is long overdue and is essential to ensure consistent product QSE of commercially available Ginkgo biloba solid oral dosage forms.
- Full Text:
- Date Issued: 2006
Application of reverse-flow micellar electrokinetic chromatography for the simultaneous determination of flavonols and terpene trilactones in Ginkgo biloba dosage forms
- Dubber, Mary-Jean, Kanfer, Isadore
- Authors: Dubber, Mary-Jean , Kanfer, Isadore
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6357 , http://hdl.handle.net/10962/d1006049
- Description:
A reverse-flow micellar electrokinetic chromatographic (RF-MEKC) method was developed for the simultaneous qualitative determination of 10 components consisting of the flavonol glycosides, rutin and quercitrin, the flavonol aglycones, isorhamnetin, kaempferol and quercetin, the terpene trilactones, ginkgolides A, B, C and J and the sesquiterpene, bilobalide. This method was used to fingerprint Ginkgo biloba solid oral dosage forms and validated for the quantitation of the marker compounds, rutin and quercetin in some commercial products. In addition to the usual variables, the influence of some essential background electrolyte (BGE) components such as sodium dodecyl sulphate (SDS) and
-cyclodextrin concentrations were investigated. A polyimide fused-silica square capillary column (75 μm I.D. × 360 μm O.D.) with a total length of 60.0 cm and effective length of 45.0 cm was used for the separation. The final BGE consisted of 20 mM phosphoric acid, 40 mM SDS and 12 mM -cyclodextrin (pH 2.2) using reverse polarity with a voltage of −17.5 kV. Samples were injected electrokinetically at −5 kV for 3 s for the qualitative analysis and hydrodynamically at 20 mbar for 0.6 s for the quantitative assay. The total run time was 22 min and the limits of detection were 3.13 μg/ml and 1.88 μg/ml for rutin and quercetin, respectively. Fingerprint profiles of the solid oral dosage forms and the results of the quantitative analysis indicated that there were major discrepancies in the marker content between products and illustrates the value of this method for use as a procedure to assess product quality of commercially available Ginkgo biloba products. - Full Text:
- Date Issued: 2006
- Authors: Dubber, Mary-Jean , Kanfer, Isadore
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6357 , http://hdl.handle.net/10962/d1006049
- Description:
A reverse-flow micellar electrokinetic chromatographic (RF-MEKC) method was developed for the simultaneous qualitative determination of 10 components consisting of the flavonol glycosides, rutin and quercitrin, the flavonol aglycones, isorhamnetin, kaempferol and quercetin, the terpene trilactones, ginkgolides A, B, C and J and the sesquiterpene, bilobalide. This method was used to fingerprint Ginkgo biloba solid oral dosage forms and validated for the quantitation of the marker compounds, rutin and quercetin in some commercial products. In addition to the usual variables, the influence of some essential background electrolyte (BGE) components such as sodium dodecyl sulphate (SDS) and
-cyclodextrin concentrations were investigated. A polyimide fused-silica square capillary column (75 μm I.D. × 360 μm O.D.) with a total length of 60.0 cm and effective length of 45.0 cm was used for the separation. The final BGE consisted of 20 mM phosphoric acid, 40 mM SDS and 12 mM -cyclodextrin (pH 2.2) using reverse polarity with a voltage of −17.5 kV. Samples were injected electrokinetically at −5 kV for 3 s for the qualitative analysis and hydrodynamically at 20 mbar for 0.6 s for the quantitative assay. The total run time was 22 min and the limits of detection were 3.13 μg/ml and 1.88 μg/ml for rutin and quercetin, respectively. Fingerprint profiles of the solid oral dosage forms and the results of the quantitative analysis indicated that there were major discrepancies in the marker content between products and illustrates the value of this method for use as a procedure to assess product quality of commercially available Ginkgo biloba products. - Full Text:
- Date Issued: 2006
Application of the Baylis-Hillman reaction in the preparation of quinoline derivatives
- Authors: Pakade, Vusumzi Emmanuel
- Date: 2006 , 2013-06-11
- Subjects: Heterocyclic compounds -- Derivatives , Quinoline
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4442 , http://hdl.handle.net/10962/d1007669 , Heterocyclic compounds -- Derivatives , Quinoline
- Description: The reaction of various 2-nitrobenzaldehyde derivatives with methyl vinyl ketone (MVK) in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) has afforded the Baylis-Hillman adducts in moderate to good yield. Dissolution of the catalyst in the solvent before the addition of the aldehyde was observed to improve the yield. Reduction of the Baylis-Hillman adducts was effected by catalytic hydrogenation using a 10% palladium-on- carbon catalyst in ethanol to give quinoline and quinoline-N-oxide derivatives and, in some cases, acyclic reduction products. All products were characterised using NMR and, where appropriate, HRMS methods. Selected quinoline-N-oxides were successfully converted to their corresponding quinoline derivatives using phosphorus tribromide (PBr₃) and DMF as solvent. Conjugate addition of the benzylamine and piperidine nucleophiles to the Baylis-Hillman adducts was also investigated but proved problematic, with one of the substrates undergoing a retro-Baylis-Hillman reaction to afford the aldehyde in ca. 40% yield, but seemingly only traces of the required product. Perkin-type coupling of two 2-methylquinolines with benzaldehyde was successfully effected to afford the desired styrylquinoline derivatives confirming the potential of the Baylis-Hillman approach to the construction of the analogues of known HIV-1 integrase inhibitors. Three ¹³C NMR chemical shift prediction programmes, viz., Chem Window, neural network and HOSE (hierarchically ordered spherical description of environment) methods were applied to selected representative compounds prepared in the project. The results from the three programmes correlated reasonably well with the experimental carbon-13 chemical shift data for each of the selected compounds.
- Full Text:
- Date Issued: 2006
- Authors: Pakade, Vusumzi Emmanuel
- Date: 2006 , 2013-06-11
- Subjects: Heterocyclic compounds -- Derivatives , Quinoline
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4442 , http://hdl.handle.net/10962/d1007669 , Heterocyclic compounds -- Derivatives , Quinoline
- Description: The reaction of various 2-nitrobenzaldehyde derivatives with methyl vinyl ketone (MVK) in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) has afforded the Baylis-Hillman adducts in moderate to good yield. Dissolution of the catalyst in the solvent before the addition of the aldehyde was observed to improve the yield. Reduction of the Baylis-Hillman adducts was effected by catalytic hydrogenation using a 10% palladium-on- carbon catalyst in ethanol to give quinoline and quinoline-N-oxide derivatives and, in some cases, acyclic reduction products. All products were characterised using NMR and, where appropriate, HRMS methods. Selected quinoline-N-oxides were successfully converted to their corresponding quinoline derivatives using phosphorus tribromide (PBr₃) and DMF as solvent. Conjugate addition of the benzylamine and piperidine nucleophiles to the Baylis-Hillman adducts was also investigated but proved problematic, with one of the substrates undergoing a retro-Baylis-Hillman reaction to afford the aldehyde in ca. 40% yield, but seemingly only traces of the required product. Perkin-type coupling of two 2-methylquinolines with benzaldehyde was successfully effected to afford the desired styrylquinoline derivatives confirming the potential of the Baylis-Hillman approach to the construction of the analogues of known HIV-1 integrase inhibitors. Three ¹³C NMR chemical shift prediction programmes, viz., Chem Window, neural network and HOSE (hierarchically ordered spherical description of environment) methods were applied to selected representative compounds prepared in the project. The results from the three programmes correlated reasonably well with the experimental carbon-13 chemical shift data for each of the selected compounds.
- Full Text:
- Date Issued: 2006
Aspects of the sentencing process in child sexual abuse cases
- Authors: Van der Merwe, Annette
- Date: 2006
- Subjects: Child sexual abuse -- South Africa , Sexually abused children -- Legal status, laws, etc -- South Africa , Child abuse -- Law and legislation -- South Africa , Sex crimes -- South Africa , Sentences(Criminal procedure) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3696 , http://hdl.handle.net/10962/d1003211 , Child sexual abuse -- South Africa , Sexually abused children -- Legal status, laws, etc -- South Africa , Child abuse -- Law and legislation -- South Africa , Sex crimes -- South Africa , Sentences(Criminal procedure) -- South Africa
- Description: This thesis investigates current sentencing practices relating to the diverse, complex and emotionally laden phenomenon of child sexual abuse. It focuses on relevant legislative provisions, on case law and on an empirical study conducted amongst regional court magistrates. Trends, developments and problems are analysed and possible solutions to the main problems identified are investigated. The thesis concludes with proposed guidelines regarding the sentencing process in child sexual abuse cases. Such guidelines address general and specific principles, the use of victim impact statements, the increased recognition and use of behavioural science in the sentencing phase with regard to both the victim and the offender, and relevant aggravating and mitigating factors. The guidelines are an attempt to give some structure to the current haphazard approach adopted by the courts with regard to harm experienced by the victim. They are also aimed at assisting experts to provide more effective and reliable pre-sentence reports. Further, the thesis attempts to provide clarity concerning the factors that are considered to be aggravating or mitigating in the offence category, child sexual abuse, as well as with regard to the weight that should be attached to them. In addition, recommendations are made for the purpose of possible law reform and further research in relation to the regulation of judicial discretion through the introduction of formal sentencing guidelines, victim impact statements and the accommodation of behavioural science in the sentencing process pertaining to sexual offenders. This proposal is based on current South African sentencing practices as reflected in the consolidation of local judgments scattered over many years in different law reports and, to some extent, on English, Canadian, Australian and American sentencing practices as researched in this study.
- Full Text:
- Date Issued: 2006
- Authors: Van der Merwe, Annette
- Date: 2006
- Subjects: Child sexual abuse -- South Africa , Sexually abused children -- Legal status, laws, etc -- South Africa , Child abuse -- Law and legislation -- South Africa , Sex crimes -- South Africa , Sentences(Criminal procedure) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3696 , http://hdl.handle.net/10962/d1003211 , Child sexual abuse -- South Africa , Sexually abused children -- Legal status, laws, etc -- South Africa , Child abuse -- Law and legislation -- South Africa , Sex crimes -- South Africa , Sentences(Criminal procedure) -- South Africa
- Description: This thesis investigates current sentencing practices relating to the diverse, complex and emotionally laden phenomenon of child sexual abuse. It focuses on relevant legislative provisions, on case law and on an empirical study conducted amongst regional court magistrates. Trends, developments and problems are analysed and possible solutions to the main problems identified are investigated. The thesis concludes with proposed guidelines regarding the sentencing process in child sexual abuse cases. Such guidelines address general and specific principles, the use of victim impact statements, the increased recognition and use of behavioural science in the sentencing phase with regard to both the victim and the offender, and relevant aggravating and mitigating factors. The guidelines are an attempt to give some structure to the current haphazard approach adopted by the courts with regard to harm experienced by the victim. They are also aimed at assisting experts to provide more effective and reliable pre-sentence reports. Further, the thesis attempts to provide clarity concerning the factors that are considered to be aggravating or mitigating in the offence category, child sexual abuse, as well as with regard to the weight that should be attached to them. In addition, recommendations are made for the purpose of possible law reform and further research in relation to the regulation of judicial discretion through the introduction of formal sentencing guidelines, victim impact statements and the accommodation of behavioural science in the sentencing process pertaining to sexual offenders. This proposal is based on current South African sentencing practices as reflected in the consolidation of local judgments scattered over many years in different law reports and, to some extent, on English, Canadian, Australian and American sentencing practices as researched in this study.
- Full Text:
- Date Issued: 2006
Assessing the impact of the lean manufacturing supplier development practices of an Eastern Cape vehicle manufacturer
- Authors: Botha, Christo Johannes
- Date: 2006
- Subjects: Production management , Automobile industry and trade -- South Africa -- Eastern Cape , Industrial procurement
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8558 , http://hdl.handle.net/10948/480 , Production management , Automobile industry and trade -- South Africa -- Eastern Cape , Industrial procurement
- Description: The world automotive industry has evolved through different manufacturing methodologies over many decades. It originated from craft production, but was transformed to mass production by Henry Ford in response to increased market demand. The methodology developed by Henry Ford made it possible to produce quality vehicles in large numbers and at affordable cost to the general public. However, it cannot deliver a great variety of products to the marketplace. Mass production was overtaken by a new automotive manufacturing methodology developed in Japan after World War II. The methodology, commonly referred to as lean production, yields consistently high quality products at even lower costs, whilst being able to deliver a variety of products to the consumer. The effectiveness of the lean production methodology hinges upon the strength and closeness of the relationships that exist between the assembler and its suppliers. Different models have been developed over time to describe the relationships between automotive assemblers and their suppliers. The lean supply model is generally accepted as an effective way of describing the relationships that exist between an automotive assembler and its first tier suppliers in a lean manufacturing environment. The research study aims at gaining an improved understanding of the relationships that exist between a selected Eastern Cape automotive assembler and its first tier suppliers. The effect of its supplier support practices towards lean manufacturing implementation amongst its first tier suppliers is evaluated. For the selected assembler it is found that the effect of its supplier support practices on lean manufacturing implementation amongst its first tier suppliers is limited by a non-uniform approach followed towards the supplier base. It is shown that opportunities for improvement exist for the selected assembler to develop closer relationships with its first tier suppliers to increase its global competitiveness.
- Full Text:
- Date Issued: 2006
- Authors: Botha, Christo Johannes
- Date: 2006
- Subjects: Production management , Automobile industry and trade -- South Africa -- Eastern Cape , Industrial procurement
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8558 , http://hdl.handle.net/10948/480 , Production management , Automobile industry and trade -- South Africa -- Eastern Cape , Industrial procurement
- Description: The world automotive industry has evolved through different manufacturing methodologies over many decades. It originated from craft production, but was transformed to mass production by Henry Ford in response to increased market demand. The methodology developed by Henry Ford made it possible to produce quality vehicles in large numbers and at affordable cost to the general public. However, it cannot deliver a great variety of products to the marketplace. Mass production was overtaken by a new automotive manufacturing methodology developed in Japan after World War II. The methodology, commonly referred to as lean production, yields consistently high quality products at even lower costs, whilst being able to deliver a variety of products to the consumer. The effectiveness of the lean production methodology hinges upon the strength and closeness of the relationships that exist between the assembler and its suppliers. Different models have been developed over time to describe the relationships between automotive assemblers and their suppliers. The lean supply model is generally accepted as an effective way of describing the relationships that exist between an automotive assembler and its first tier suppliers in a lean manufacturing environment. The research study aims at gaining an improved understanding of the relationships that exist between a selected Eastern Cape automotive assembler and its first tier suppliers. The effect of its supplier support practices towards lean manufacturing implementation amongst its first tier suppliers is evaluated. For the selected assembler it is found that the effect of its supplier support practices on lean manufacturing implementation amongst its first tier suppliers is limited by a non-uniform approach followed towards the supplier base. It is shown that opportunities for improvement exist for the selected assembler to develop closer relationships with its first tier suppliers to increase its global competitiveness.
- Full Text:
- Date Issued: 2006
Assessing the potential of submaximal extended duration exercise as an adjunct treatment for sub-acute schizophrenic in-patients: a pilot study
- Authors: Munnik, James Barry
- Date: 2006
- Subjects: Aerobic exercises -- Therapeutic use , Schizophrenia , Schizophrenia -- Treatment , Exercise therapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3029 , http://hdl.handle.net/10962/d1002538 , Aerobic exercises -- Therapeutic use , Schizophrenia , Schizophrenia -- Treatment , Exercise therapy
- Description: Research into the therapeutic potential of aerobic exercise has proven fruitful over the past few years; however, no true experimental research undertakings have investigated the psychological benefits of aerobic exercise with schizophrenic semi-acute in-patients. The main objective of this thesis was to seek out evidence for the possibility that aerobic (submaximal long duration) exercise could be considered an adjunct treatment for hospitalised schizophrenic in-patients. In order to accomplish this objective the effects of a 45-minute walking programme, completed three days a week, for five weeks, was investigated. Various areas of mental health were explored in search of evidence of the therapeutic potential of aerobic exercise. These areas included, amongst other things: transfer and discharge rates, improvements in mood levels - Beck Depression Inventory-II (BDI-II; Beck, Steer, and Brown, 1996) Xhosa version; decreasing of anxiety levels (Beck Anxiety Inventory (BAI; Beck and Steer, 1993), Xhosa version); improved Global Assessment of Functioning (GAF; DSM-IV), Scale Scores; and decreases in the number of symptoms patients exhibited. 22 schizophrenic inpatients were randomly selected for this study and randomly assigned to either an aerobic (long duration submaximal) treatment group or (primarily anaerobic) control group. Results revealed that statistical significance could not be found in any of the treatment group's t-test results; despite the treatment group generally bordering on significance more so than the control group. Out of the five variables studied (Positive Symptoms, Negative Symptoms, BAI, BDI-II, and GAF Scale) three variables (Negative Symptoms, BDI-II, and GAF Scale) in the treatment group bordered more on significance than did the control group. Thus three (60 %) out of the five areas studied revealed that the treatment group had more significant results. This suggests an overall impression that the treatment group responded slightly better. The Researcher recommended that aerobic exercise therapy be considered a treatment protocol in psychiatric institutions and offered further suggestions pertaining to the effective implementation of these programmes. Included in these recommendations were motivational strategies and warnings about the possible negative effects of exercise therapy. A supplemental goal of this thesis was to explore all of the previously offered theoretical psychological mechanisms of positive mental change; and to seek out evidence, for or against these forces. Participants were given pre- and post- treatment quantitative interviews; as well as, qualitative posttreatment interviews where their phenomenological responses were analysed to seek out evidence of these mechanisms. Evidence of various causative factors was found and a new theoretical mechanism was proposed in this thesis.
- Full Text:
- Date Issued: 2006
- Authors: Munnik, James Barry
- Date: 2006
- Subjects: Aerobic exercises -- Therapeutic use , Schizophrenia , Schizophrenia -- Treatment , Exercise therapy
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3029 , http://hdl.handle.net/10962/d1002538 , Aerobic exercises -- Therapeutic use , Schizophrenia , Schizophrenia -- Treatment , Exercise therapy
- Description: Research into the therapeutic potential of aerobic exercise has proven fruitful over the past few years; however, no true experimental research undertakings have investigated the psychological benefits of aerobic exercise with schizophrenic semi-acute in-patients. The main objective of this thesis was to seek out evidence for the possibility that aerobic (submaximal long duration) exercise could be considered an adjunct treatment for hospitalised schizophrenic in-patients. In order to accomplish this objective the effects of a 45-minute walking programme, completed three days a week, for five weeks, was investigated. Various areas of mental health were explored in search of evidence of the therapeutic potential of aerobic exercise. These areas included, amongst other things: transfer and discharge rates, improvements in mood levels - Beck Depression Inventory-II (BDI-II; Beck, Steer, and Brown, 1996) Xhosa version; decreasing of anxiety levels (Beck Anxiety Inventory (BAI; Beck and Steer, 1993), Xhosa version); improved Global Assessment of Functioning (GAF; DSM-IV), Scale Scores; and decreases in the number of symptoms patients exhibited. 22 schizophrenic inpatients were randomly selected for this study and randomly assigned to either an aerobic (long duration submaximal) treatment group or (primarily anaerobic) control group. Results revealed that statistical significance could not be found in any of the treatment group's t-test results; despite the treatment group generally bordering on significance more so than the control group. Out of the five variables studied (Positive Symptoms, Negative Symptoms, BAI, BDI-II, and GAF Scale) three variables (Negative Symptoms, BDI-II, and GAF Scale) in the treatment group bordered more on significance than did the control group. Thus three (60 %) out of the five areas studied revealed that the treatment group had more significant results. This suggests an overall impression that the treatment group responded slightly better. The Researcher recommended that aerobic exercise therapy be considered a treatment protocol in psychiatric institutions and offered further suggestions pertaining to the effective implementation of these programmes. Included in these recommendations were motivational strategies and warnings about the possible negative effects of exercise therapy. A supplemental goal of this thesis was to explore all of the previously offered theoretical psychological mechanisms of positive mental change; and to seek out evidence, for or against these forces. Participants were given pre- and post- treatment quantitative interviews; as well as, qualitative posttreatment interviews where their phenomenological responses were analysed to seek out evidence of these mechanisms. Evidence of various causative factors was found and a new theoretical mechanism was proposed in this thesis.
- Full Text:
- Date Issued: 2006
Assessing the role of leadership in strategic planning
- Authors: Solomon, Wesley Anthony
- Date: 2006
- Subjects: Leadership , Strategic planning , Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8758 , http://hdl.handle.net/10948/609 , Leadership , Strategic planning , Management
- Description: Effective leadership is one of the most important factors that influence the performance of an organization. Effective leadership together with supervision are similar in terms of their influence on others towards achieving the goals of the organization. Therefore, effective leadership and supervision are principal activities through which organizational goals and objectives are achieved.
- Full Text:
- Date Issued: 2006
- Authors: Solomon, Wesley Anthony
- Date: 2006
- Subjects: Leadership , Strategic planning , Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8758 , http://hdl.handle.net/10948/609 , Leadership , Strategic planning , Management
- Description: Effective leadership is one of the most important factors that influence the performance of an organization. Effective leadership together with supervision are similar in terms of their influence on others towards achieving the goals of the organization. Therefore, effective leadership and supervision are principal activities through which organizational goals and objectives are achieved.
- Full Text:
- Date Issued: 2006
Assessment of the effect of Goukamma Marine Protected Area on community structure and fishery dynamics
- Authors: Götz, Albrecht
- Date: 2006
- Subjects: Goukamma Marine Protected Area Reef fishes -- South Africa Marine fishes -- South Africa Fishery management -- South Africa Marine resources conservation -- South Africa Marine parks and reserves -- South Africa Chrysoblephus laticeps Merluccius Argyrosomus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5230 , http://hdl.handle.net/10962/d1005073
- Description: This study presents a detailed investigation into size, density and community structure of temperate marine reef fish in the medium-sized Goukamma Marine Protected Area (Goukamma MPA) and adjacent fishing grounds on the south coast of South Africa. The oceanographic conditions, the spatial distribution of the benthic community and the prevailing fishing effort are also described. Life history traits and per-recruit (PR) models for the principle target species, roman (Crysoblephus laticeps) are compared between the protected and exploited area. From the study results, various strategies are proposed for the use of MPAs in the conservation and management of linefish species along South Africa’s south coast. The distribution and topography of reefs in the protected and exploited sections of the study area were found to be comparable. Atmospheric pressure ranged from 992 to 1,032 mb, being significantly lower in summer. Wind speeds ranged from 0.7 to 71.3 km/h. Water temperatures ranged between 9.0 and 22.2 ºC and turbidity between 0.3 and 45.8 NTU. Water temperature and clarity were uniformly low in winter. In summer the water was generally warm, clear and stratified, with a thermocline at around 20 m, although intermittent upwelling events caused water temperature to decrease and clarity to deteriorate. Current speeds ranged between 0.11 and 2.59 km/h and were significantly higher in spring and autumn. Easterly currents prevailed in spring, summer and autumn and westerly and southerly currents in winter. Hake (Merluccius capensis), various resident reef fish and kob (Argyrosomus japonicus) were most frequently targeted by the local linefishery. A significant amount of illegal fishing was found to occur in the protected area. Fishing effort was found to be highest around the border of the MPA (2.7 boats/km²) and lowest in the core of the MPA (0.2 boats/km²). If law enforcement remains poor it may be necessary to adapt the management strategy to extend the reserve, thereby mitigating against illegal fishing and ensuring a core area of no exploitation. Various other alternatives were investigated and it was demonstrated that the amount of fish caught of legal size could be increased by about 23% and post-release mortality of undersized fish reduced by 50% through the introduction of a suit of restrictive measures. Randomly stratified underwater visual census (UVC) and controlled fishing were used to investigate the ichthyofauna and benthic community at protected and exploited sites in the study area. Resulting density and size data from 273 fishing sites and 177 point counts were analyzed using generalized linear models (GLMs). Fish communities were found to vary significantly, depending on the level of exploitation. Roman, the principle reef fish species targeted by the fishery had significantly higher densities within the protected parts of the study area (CPUE: 4.3 fish/anglerhour; UVC: 2.2 fish/point-count) as compared to the exploited part (CPUE: 3.4 fish/anglerhour; UVC: 1.8 fish/point-count), correlating strongly with the observed fishing effort. Also mean sizes were significantly higher in the protected area (299 mm from fishing survey and 233 mm from diving estimates) as compared to the exploited section (283 mm from fishing survey and 198 mm from diving estimates). Although other fish species also had significantly higher mean sizes at protected sites in most cases their densities were significantly lower. This suggests a top-down control of the fish community by the dominant predator (roman). The results of the UVC showed the diversity of the ichthyofauna to be significantly higher inside the protected area. Interestingly this did not apply to the results of the controlled fishing experiment where the diversity of fish in the catch was lower in the protected area - a result that may be explained by the selectivity of fishing for the most aggressive species – and a reminder of the limitations of controlled fishing experiments. Possibly the most important finding of the study revolved around the benthic community. These were significantly different at exploited and protected sites, with algae and crinoids more abundant at exploited sites. Crinoids are the principle food of roman and were low in abundance where roman abundances were high, suggesting that the dominant top predator reduced crinoids. Furthermore, it substantiates the correlation of roman abundance with fishing effort, since habitat preferences can be ruled out by the observed causal predator-prey distribution pattern. Low algae abundances at protected sites correlated with high strepie (Sarpa salpa) frequencies within the fish communities encountered there. Strepie, a shoaling and abundant benthic grazer, does not compete for food with roman, suggesting a high potential for coexistence of the two species. As expected, and found by other studies, life history traits of roman differed between protected and exploited sample-sites. With a significantly lower age-at-maturity and age-atsex- change, the exploited population showed a typical response to fishing effort. The sex ratio of this protogynous hermaphrodite was found to be sustained at healthy levels by phenotypic plasticity. However, one important additional factor was highlighted by the study; the average condition factor of the protected population was significantly lower (0.0283 g/cm³) compared to the exploited population (0.0295 g/cm³). This was probably due to the higher intra-specific competition for lower food abundance in the protected area. Interestingly the diving and fishing survey methods yielded similar mortality results for roman. Total mortality rate estimates derived from length frequency analysis from the diving and fishing survey were not different (0.32 and 0.29 y⁻¹, respectively) as were natural mortality rate estimates (0.24 and 0.19 y⁻¹, respectively). Natural mortality rate (M) estimates indicated by Pauly’s and Hoenig’s relationship were similar (0.25 and 0.23 y⁻¹, respectively). Detailed yield-per-recruit (Y/R) and spawner biomass-per-recruit (SB/R) analyses were presented for different levels of M, varying age-at-recruitment (tR) and fishing mortality (F). Current tR (7.60 y) and F (0.16 and 0.25 y⁻¹, from the diving and fishing dataset, respectively) suggests an optimal exploitation of the population in the exploited part of the study area. However, a separate SB/R analysis of the male part of the population showed their vulnerability to over-exploitation, even at reduced age-at-sex-change from fishing. There therefore remains a high risk of recruitment failure for the roman population. Of course MPAs can be used to measure stock status directly if the influence of factors such as cachability, habitat and sampling method on CPUE assessments can be limited or reduced. The experimental design in this study allowed for contemporary CPUE comparisons across the border of the Goukamma MPA. Results were similar to those obtained by the SB/R analyses. CPUE extrapolations therefore, using small MPAs, can provide reliable and consistent estimates, and offer a practical alternative to conventional assessment strategies. This study has highlighted the importance of ensuring a well structured and comprehensive survey design when undertaking a comparison of protected and exploited marine areas. The results provide a comprehensive framework for future management of the Goukamma MPA and other protected areas along the temperate coastline of South Africa.
- Full Text:
- Date Issued: 2006
- Authors: Götz, Albrecht
- Date: 2006
- Subjects: Goukamma Marine Protected Area Reef fishes -- South Africa Marine fishes -- South Africa Fishery management -- South Africa Marine resources conservation -- South Africa Marine parks and reserves -- South Africa Chrysoblephus laticeps Merluccius Argyrosomus
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5230 , http://hdl.handle.net/10962/d1005073
- Description: This study presents a detailed investigation into size, density and community structure of temperate marine reef fish in the medium-sized Goukamma Marine Protected Area (Goukamma MPA) and adjacent fishing grounds on the south coast of South Africa. The oceanographic conditions, the spatial distribution of the benthic community and the prevailing fishing effort are also described. Life history traits and per-recruit (PR) models for the principle target species, roman (Crysoblephus laticeps) are compared between the protected and exploited area. From the study results, various strategies are proposed for the use of MPAs in the conservation and management of linefish species along South Africa’s south coast. The distribution and topography of reefs in the protected and exploited sections of the study area were found to be comparable. Atmospheric pressure ranged from 992 to 1,032 mb, being significantly lower in summer. Wind speeds ranged from 0.7 to 71.3 km/h. Water temperatures ranged between 9.0 and 22.2 ºC and turbidity between 0.3 and 45.8 NTU. Water temperature and clarity were uniformly low in winter. In summer the water was generally warm, clear and stratified, with a thermocline at around 20 m, although intermittent upwelling events caused water temperature to decrease and clarity to deteriorate. Current speeds ranged between 0.11 and 2.59 km/h and were significantly higher in spring and autumn. Easterly currents prevailed in spring, summer and autumn and westerly and southerly currents in winter. Hake (Merluccius capensis), various resident reef fish and kob (Argyrosomus japonicus) were most frequently targeted by the local linefishery. A significant amount of illegal fishing was found to occur in the protected area. Fishing effort was found to be highest around the border of the MPA (2.7 boats/km²) and lowest in the core of the MPA (0.2 boats/km²). If law enforcement remains poor it may be necessary to adapt the management strategy to extend the reserve, thereby mitigating against illegal fishing and ensuring a core area of no exploitation. Various other alternatives were investigated and it was demonstrated that the amount of fish caught of legal size could be increased by about 23% and post-release mortality of undersized fish reduced by 50% through the introduction of a suit of restrictive measures. Randomly stratified underwater visual census (UVC) and controlled fishing were used to investigate the ichthyofauna and benthic community at protected and exploited sites in the study area. Resulting density and size data from 273 fishing sites and 177 point counts were analyzed using generalized linear models (GLMs). Fish communities were found to vary significantly, depending on the level of exploitation. Roman, the principle reef fish species targeted by the fishery had significantly higher densities within the protected parts of the study area (CPUE: 4.3 fish/anglerhour; UVC: 2.2 fish/point-count) as compared to the exploited part (CPUE: 3.4 fish/anglerhour; UVC: 1.8 fish/point-count), correlating strongly with the observed fishing effort. Also mean sizes were significantly higher in the protected area (299 mm from fishing survey and 233 mm from diving estimates) as compared to the exploited section (283 mm from fishing survey and 198 mm from diving estimates). Although other fish species also had significantly higher mean sizes at protected sites in most cases their densities were significantly lower. This suggests a top-down control of the fish community by the dominant predator (roman). The results of the UVC showed the diversity of the ichthyofauna to be significantly higher inside the protected area. Interestingly this did not apply to the results of the controlled fishing experiment where the diversity of fish in the catch was lower in the protected area - a result that may be explained by the selectivity of fishing for the most aggressive species – and a reminder of the limitations of controlled fishing experiments. Possibly the most important finding of the study revolved around the benthic community. These were significantly different at exploited and protected sites, with algae and crinoids more abundant at exploited sites. Crinoids are the principle food of roman and were low in abundance where roman abundances were high, suggesting that the dominant top predator reduced crinoids. Furthermore, it substantiates the correlation of roman abundance with fishing effort, since habitat preferences can be ruled out by the observed causal predator-prey distribution pattern. Low algae abundances at protected sites correlated with high strepie (Sarpa salpa) frequencies within the fish communities encountered there. Strepie, a shoaling and abundant benthic grazer, does not compete for food with roman, suggesting a high potential for coexistence of the two species. As expected, and found by other studies, life history traits of roman differed between protected and exploited sample-sites. With a significantly lower age-at-maturity and age-atsex- change, the exploited population showed a typical response to fishing effort. The sex ratio of this protogynous hermaphrodite was found to be sustained at healthy levels by phenotypic plasticity. However, one important additional factor was highlighted by the study; the average condition factor of the protected population was significantly lower (0.0283 g/cm³) compared to the exploited population (0.0295 g/cm³). This was probably due to the higher intra-specific competition for lower food abundance in the protected area. Interestingly the diving and fishing survey methods yielded similar mortality results for roman. Total mortality rate estimates derived from length frequency analysis from the diving and fishing survey were not different (0.32 and 0.29 y⁻¹, respectively) as were natural mortality rate estimates (0.24 and 0.19 y⁻¹, respectively). Natural mortality rate (M) estimates indicated by Pauly’s and Hoenig’s relationship were similar (0.25 and 0.23 y⁻¹, respectively). Detailed yield-per-recruit (Y/R) and spawner biomass-per-recruit (SB/R) analyses were presented for different levels of M, varying age-at-recruitment (tR) and fishing mortality (F). Current tR (7.60 y) and F (0.16 and 0.25 y⁻¹, from the diving and fishing dataset, respectively) suggests an optimal exploitation of the population in the exploited part of the study area. However, a separate SB/R analysis of the male part of the population showed their vulnerability to over-exploitation, even at reduced age-at-sex-change from fishing. There therefore remains a high risk of recruitment failure for the roman population. Of course MPAs can be used to measure stock status directly if the influence of factors such as cachability, habitat and sampling method on CPUE assessments can be limited or reduced. The experimental design in this study allowed for contemporary CPUE comparisons across the border of the Goukamma MPA. Results were similar to those obtained by the SB/R analyses. CPUE extrapolations therefore, using small MPAs, can provide reliable and consistent estimates, and offer a practical alternative to conventional assessment strategies. This study has highlighted the importance of ensuring a well structured and comprehensive survey design when undertaking a comparison of protected and exploited marine areas. The results provide a comprehensive framework for future management of the Goukamma MPA and other protected areas along the temperate coastline of South Africa.
- Full Text:
- Date Issued: 2006
Atlas of Southern African freshwater fishes
- Scott, L E P, Skelton, P H, Booth, A J, Verheust, L, Dooley, J, Harris, R
- Authors: Scott, L E P , Skelton, P H , Booth, A J , Verheust, L , Dooley, J , Harris, R
- Date: 2006
- Subjects: Freshwater fishes -- South Africa , Freshwater fishes -- Africa, Southern , Freshwater fishes -- Africa, Southern -- Identification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/199097 , vital:46068
- Description: Worldwide concern over the loss of biological diversity during the past decade has provided the impetus for the development of biodiversity databases and biological atlas projects in order to make information accessible. This Geographic Information Systems-based Atlas of Southern African Freshwater Fishes is the first of its kind for fishes in Africa and, as such, can be seen as contributing towards this global trend of consolidation and refining of biodiversity information. The technological advances made in computing systems over the past decade have facilitated the extraction and utilisation of much of the untapped information in museum collections. The size of most natural history collections had tended to prohibit any comprehensive applied use of the specimens on a large scale, but the computerisation of these collections has proved to be an invaluable tool to systematists, taxonomists and ecologists, by allowing faster and more efficient access to specimen record data of interest. With the automation of many biological databases, public attention has been brought to their potential contribution to biodiversity studies and conservation efforts around the world. The application of Geographic Information Systems (GIS) in the field of southern African ichthyology and freshwater fisheries management has been limited, until now, by the lack of good-quality, comprehensive data sets, adequate budgets and GIS skills. Sophisticated investigations of fish distributions for conservation and management purposes need a powerful computing platform. This is realised in the Atlas of Southern African Freshwater Fishes, which has been tested and used for biogeographic analysis in the southern African region. The atlas was established using specimen records from nineteen museum collections, and currently contains 35145 geo-referenced specimen records, collected between 1885 and 2000 in eleven countries of southern Africa, which represent 254 fish species from 37 families. The Atlas of Southern African Freshwater Fishes was developed with the objective of being a dynamic, powerful information system. It has been constructed to allow the import of additional information at any stage, and it is designed to be as accessible and as user-friendly as current technology allows. This Atlas is the product of the successful integration of fish distributional information with other spatial data layers to provide a new tool for the study of freshwater fish in southern Africa.
- Full Text:
- Date Issued: 2006
- Authors: Scott, L E P , Skelton, P H , Booth, A J , Verheust, L , Dooley, J , Harris, R
- Date: 2006
- Subjects: Freshwater fishes -- South Africa , Freshwater fishes -- Africa, Southern , Freshwater fishes -- Africa, Southern -- Identification
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/199097 , vital:46068
- Description: Worldwide concern over the loss of biological diversity during the past decade has provided the impetus for the development of biodiversity databases and biological atlas projects in order to make information accessible. This Geographic Information Systems-based Atlas of Southern African Freshwater Fishes is the first of its kind for fishes in Africa and, as such, can be seen as contributing towards this global trend of consolidation and refining of biodiversity information. The technological advances made in computing systems over the past decade have facilitated the extraction and utilisation of much of the untapped information in museum collections. The size of most natural history collections had tended to prohibit any comprehensive applied use of the specimens on a large scale, but the computerisation of these collections has proved to be an invaluable tool to systematists, taxonomists and ecologists, by allowing faster and more efficient access to specimen record data of interest. With the automation of many biological databases, public attention has been brought to their potential contribution to biodiversity studies and conservation efforts around the world. The application of Geographic Information Systems (GIS) in the field of southern African ichthyology and freshwater fisheries management has been limited, until now, by the lack of good-quality, comprehensive data sets, adequate budgets and GIS skills. Sophisticated investigations of fish distributions for conservation and management purposes need a powerful computing platform. This is realised in the Atlas of Southern African Freshwater Fishes, which has been tested and used for biogeographic analysis in the southern African region. The atlas was established using specimen records from nineteen museum collections, and currently contains 35145 geo-referenced specimen records, collected between 1885 and 2000 in eleven countries of southern Africa, which represent 254 fish species from 37 families. The Atlas of Southern African Freshwater Fishes was developed with the objective of being a dynamic, powerful information system. It has been constructed to allow the import of additional information at any stage, and it is designed to be as accessible and as user-friendly as current technology allows. This Atlas is the product of the successful integration of fish distributional information with other spatial data layers to provide a new tool for the study of freshwater fish in southern Africa.
- Full Text:
- Date Issued: 2006
ATP-sulphurylase: An enzymatic marker for biological sulphate reduction
- Oyekola, Oluwaseun O, Pletschke, Brett I
- Authors: Oyekola, Oluwaseun O , Pletschke, Brett I
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6461 , http://hdl.handle.net/10962/d1005790 , http://dx.doi.org/10.1016/j.soilbio.2006.05.014
- Description: Adenosine triphosphate-sulphurylase (ATPS) plays a major role in dissimilatory sulphate reduction. In this study, the level of ATPS activity was monitored in a time course study using a biosulphidogenic batch bioreactor system. A coincident decrease in ATPS activity with a decline in sulphate concentration and an increase in sulphide concentration as biosulphidogenesis proceeded was observed. Flask studies further showed sulphate to be stimulatory to ATPS, while sulphide proved to be inhibitory. The effect of ions (Ca^(2+), Cl^(−), Fe^(2+) and Zn^(2+)) on the ATPS activity was also investigated. Most of the ions studied (Ca^(2+), Cl^(−) and Fe^(2+)) were stimulatory at lower concentrations (40–120 mg/l) but proved toxic at higher concentrations (>120 mg/l). In contrast, Zn^(2+) was inhibitory even at low concentrations ( 40 mg/l). ATPS may potentially be used as an enzymatic marker for biological sulphate reduction in sulphate-rich wastewaters and natural environments (anaerobic systems such as soils and sediments found in freshwater and marine systems), providing all residual sulphide and interfering ions are removed using a simple preparative step.
- Full Text:
- Date Issued: 2006
- Authors: Oyekola, Oluwaseun O , Pletschke, Brett I
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6461 , http://hdl.handle.net/10962/d1005790 , http://dx.doi.org/10.1016/j.soilbio.2006.05.014
- Description: Adenosine triphosphate-sulphurylase (ATPS) plays a major role in dissimilatory sulphate reduction. In this study, the level of ATPS activity was monitored in a time course study using a biosulphidogenic batch bioreactor system. A coincident decrease in ATPS activity with a decline in sulphate concentration and an increase in sulphide concentration as biosulphidogenesis proceeded was observed. Flask studies further showed sulphate to be stimulatory to ATPS, while sulphide proved to be inhibitory. The effect of ions (Ca^(2+), Cl^(−), Fe^(2+) and Zn^(2+)) on the ATPS activity was also investigated. Most of the ions studied (Ca^(2+), Cl^(−) and Fe^(2+)) were stimulatory at lower concentrations (40–120 mg/l) but proved toxic at higher concentrations (>120 mg/l). In contrast, Zn^(2+) was inhibitory even at low concentrations ( 40 mg/l). ATPS may potentially be used as an enzymatic marker for biological sulphate reduction in sulphate-rich wastewaters and natural environments (anaerobic systems such as soils and sediments found in freshwater and marine systems), providing all residual sulphide and interfering ions are removed using a simple preparative step.
- Full Text:
- Date Issued: 2006
Attachment and the therapeutic relationship an elucidation of therapeutic process in a single child psychotherapy case
- Authors: Crafford, Melody
- Date: 2006
- Subjects: Child psychotherapy -- Case studies , Psychotherapist and patient , Attachment behavior in children
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2955 , http://hdl.handle.net/10962/d1002464 , Child psychotherapy -- Case studies , Psychotherapist and patient , Attachment behavior in children
- Description: The overall objective of this study was to delve into the intricacies of the therapeutic process and the therapeutic relationship from an attachment perspective. A single retrospective child case study was conducted, which entailed the construction of a narrative synopsis of the process. The hermeneutic approach of a Reading Guide Method was applied, and through a repeated re-reading of the narrative, pertinent themes emerged that shed light on therapy as a process in motion. Specifically, the motion of the therapeutic process manifested through a scrutiny of the therapeutic relationship in view of the participant’s attachment style. The results of this study revealed the capacity of the participant to move away from an avoidant and somewhat ambivalent organisation of defences by virtue of establishing a secure base and exercising her faculty for emotional and self-expression. Accordingly, it can be established that in view of psychotherapy from an attachment perspective, the seemingly imperceptible vicissitudes of change are indeed appreciable.
- Full Text:
- Date Issued: 2006
- Authors: Crafford, Melody
- Date: 2006
- Subjects: Child psychotherapy -- Case studies , Psychotherapist and patient , Attachment behavior in children
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2955 , http://hdl.handle.net/10962/d1002464 , Child psychotherapy -- Case studies , Psychotherapist and patient , Attachment behavior in children
- Description: The overall objective of this study was to delve into the intricacies of the therapeutic process and the therapeutic relationship from an attachment perspective. A single retrospective child case study was conducted, which entailed the construction of a narrative synopsis of the process. The hermeneutic approach of a Reading Guide Method was applied, and through a repeated re-reading of the narrative, pertinent themes emerged that shed light on therapy as a process in motion. Specifically, the motion of the therapeutic process manifested through a scrutiny of the therapeutic relationship in view of the participant’s attachment style. The results of this study revealed the capacity of the participant to move away from an avoidant and somewhat ambivalent organisation of defences by virtue of establishing a secure base and exercising her faculty for emotional and self-expression. Accordingly, it can be established that in view of psychotherapy from an attachment perspective, the seemingly imperceptible vicissitudes of change are indeed appreciable.
- Full Text:
- Date Issued: 2006
Balancing leadership patterns to promote sense of community during cell-church transitioning: a grounded theory of strategic leadership and change
- Authors: Pearse, Noel
- Date: 2006
- Subjects: Leadership -- South Africa Christian leadership Church management Strategic planning -- South Africa Grounded theory Organizational change -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1426 , http://hdl.handle.net/10962/d1003307
- Description: The aim of this research was to develop a substantive grounded theory describing the process of change and the management of organizational inertia, or resistance to change, by strategic leaders transitioning churches from a programme-based to a cell-based model. The grounded theory was developed using the conventions of the Straussian version of the grounded theory method, and relying largely upon the collection of incidents through interviews with leaders of churches that embarked upon the cell-church transition. In all, 38 interviews were conducted with leaders of churches representing a range of denominations located in a number of provinces in South Africa. Based on the premise that substantive theories are contextually bound rather than context free, the contextual characteristics of this study are highlighted. Drawing from organizational theory, it is recognised that churches can be conceptualised as solidary organizations, normative organizations, congregations and voluntary organizations or associations. Viewing churches as solidary organizations highlights the role of solidary rewards in the change process, while viewing them as congregations, emphasises their religious character. Furthermore, the context of the study is embedded in the nature of the specific type of change being embarked upon, as represented by the cell-church transition. Drawing on concepts derived from the change management literature, the type of change I investigated, I classified as intangible, episodic, teleological, second-order change, highlighting the importance of social interaction. The grounded theory that was constructed describes the phases of the change process, and how the actions of leaders interact with the sense of community of the church. Three effective patterns of leadership were identified (i.e. the freewheeler, the focused-pioneer and the reflexive-accommodator) along with their ineffective counterparts (i.e. the static non-leader, the rigid combatant and the popular people pleaser). It was argued that effective leadership involves balancing the three effective patterns over time, and that a failure to achieve this balance produced an ineffective pattern. Furthermore, ineffective leadership damaged the credibility of leaders, as their actions harmed the sense of community. A loss of credibility compromised the leader’s ability to lead change. A number of approaches to understanding organizational inertia or resistance to change were examined in an attempt to locate the grounded theory in the literature and to use the literature to shed light on the findings of this study. While this literature did provide some useful insights and confirmations, no single theoretical perspective seemed to supply a comprehensive explanation. Instead, social capital theory offered a more encompassing explanation, and as such, showed much promise as a body of literature that can be used to develop an understanding of organizational change. Finally, recommendations are made for future research and the value of this research is discussed.
- Full Text:
- Date Issued: 2006
- Authors: Pearse, Noel
- Date: 2006
- Subjects: Leadership -- South Africa Christian leadership Church management Strategic planning -- South Africa Grounded theory Organizational change -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1426 , http://hdl.handle.net/10962/d1003307
- Description: The aim of this research was to develop a substantive grounded theory describing the process of change and the management of organizational inertia, or resistance to change, by strategic leaders transitioning churches from a programme-based to a cell-based model. The grounded theory was developed using the conventions of the Straussian version of the grounded theory method, and relying largely upon the collection of incidents through interviews with leaders of churches that embarked upon the cell-church transition. In all, 38 interviews were conducted with leaders of churches representing a range of denominations located in a number of provinces in South Africa. Based on the premise that substantive theories are contextually bound rather than context free, the contextual characteristics of this study are highlighted. Drawing from organizational theory, it is recognised that churches can be conceptualised as solidary organizations, normative organizations, congregations and voluntary organizations or associations. Viewing churches as solidary organizations highlights the role of solidary rewards in the change process, while viewing them as congregations, emphasises their religious character. Furthermore, the context of the study is embedded in the nature of the specific type of change being embarked upon, as represented by the cell-church transition. Drawing on concepts derived from the change management literature, the type of change I investigated, I classified as intangible, episodic, teleological, second-order change, highlighting the importance of social interaction. The grounded theory that was constructed describes the phases of the change process, and how the actions of leaders interact with the sense of community of the church. Three effective patterns of leadership were identified (i.e. the freewheeler, the focused-pioneer and the reflexive-accommodator) along with their ineffective counterparts (i.e. the static non-leader, the rigid combatant and the popular people pleaser). It was argued that effective leadership involves balancing the three effective patterns over time, and that a failure to achieve this balance produced an ineffective pattern. Furthermore, ineffective leadership damaged the credibility of leaders, as their actions harmed the sense of community. A loss of credibility compromised the leader’s ability to lead change. A number of approaches to understanding organizational inertia or resistance to change were examined in an attempt to locate the grounded theory in the literature and to use the literature to shed light on the findings of this study. While this literature did provide some useful insights and confirmations, no single theoretical perspective seemed to supply a comprehensive explanation. Instead, social capital theory offered a more encompassing explanation, and as such, showed much promise as a body of literature that can be used to develop an understanding of organizational change. Finally, recommendations are made for future research and the value of this research is discussed.
- Full Text:
- Date Issued: 2006
Bandwidth management with the Squid caching proxy server
- Authors: Halse, Guy A
- Date: 2006
- Language: English
- Type: Conference paper
- Identifier: vital:6975 , http://hdl.handle.net/10962/d1009335
- Description: Presentation on the use of the Squid caching proxy server as a tool for bandwidth management. This formed part of the International Network for the Availability of Scientific Publications' Bandwidth Management and Optimisation Open Source Tools and Solutions project, being a series of workshops conducted throughout the developing world.
- Full Text:
- Date Issued: 2006
- Authors: Halse, Guy A
- Date: 2006
- Language: English
- Type: Conference paper
- Identifier: vital:6975 , http://hdl.handle.net/10962/d1009335
- Description: Presentation on the use of the Squid caching proxy server as a tool for bandwidth management. This formed part of the International Network for the Availability of Scientific Publications' Bandwidth Management and Optimisation Open Source Tools and Solutions project, being a series of workshops conducted throughout the developing world.
- Full Text:
- Date Issued: 2006
Bells in the Province of Southern Africa
- Authors: Lewis, Colin A
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6168 , http://hdl.handle.net/10962/d1012356 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa. , The (Anglican) Church of the Province of Southern Africa encompasses South Africa, Lesotho, Swaziland, Namibia, the islands of St. Helena, Ascension, Tristan da Cunha and other ·South Atlantic groups and extends into Mozambique and Angola. This is the area, with the exception of Angola and Namibia, covered by this exploratory article. Further research will, no doubt, add much information on the bells of the Province. The first bells known to have existed in the area now covered by the Province were reported from St. Helena in 1588, when captain Thomas Cavendish wrote that on the land there was "a church ... [and] a frame ... whereon hang two bells." At that time St. Helena was used by Portuguese seamen and the bells were probably imported from Portugal. They apparently hung outside a church .in the valley in which Jamestown is now sited. No trace of them now exists (Lewis, 2004a).
- Full Text:
- Date Issued: 2006
- Authors: Lewis, Colin A
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6168 , http://hdl.handle.net/10962/d1012356 , http://www.ringingworld.co.uk
- Description: Colin Lewis was Professor of Geography at Rhodes University, Grahamstown, South Africa from 1989 until his retirement at the end of 2007. In 1990, with the strong support of the incumbent Vice-Chancellor, Dr Derek Henderson, he instigated the Certificate in Change Ringing (Church Bell Ringing) in the Rhodes University Department of Music and Musicology - the first such course to be offered in Africa. Since that date he has lectured in the basic theory, and taught the practice of change ringing. He is the Ringing Master of the Cathedral of St Michael and St George, Grahamstown, South Africa. , The (Anglican) Church of the Province of Southern Africa encompasses South Africa, Lesotho, Swaziland, Namibia, the islands of St. Helena, Ascension, Tristan da Cunha and other ·South Atlantic groups and extends into Mozambique and Angola. This is the area, with the exception of Angola and Namibia, covered by this exploratory article. Further research will, no doubt, add much information on the bells of the Province. The first bells known to have existed in the area now covered by the Province were reported from St. Helena in 1588, when captain Thomas Cavendish wrote that on the land there was "a church ... [and] a frame ... whereon hang two bells." At that time St. Helena was used by Portuguese seamen and the bells were probably imported from Portugal. They apparently hung outside a church .in the valley in which Jamestown is now sited. No trace of them now exists (Lewis, 2004a).
- Full Text:
- Date Issued: 2006
Between the 'sectional' and the 'national' : oil, grassroots discontent and civic discourse in Nigeria
- Authors: Akpan, Wilson Ndarake
- Date: 2006
- Subjects: Petroleum industry and trade -- Nigeria Revenue -- Nigeria Nigeria -- Social conditions Nigeria -- Economic conditions Niger River Delta (Nigeria) -- Environmental conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3294 , http://hdl.handle.net/10962/d1003082
- Description: This thesis examines the social character of petroleum-related grassroots struggles in Nigeria’s oil-producing region. It does this against the background of the dominant scholarly narratives that portray the struggles as: a) a disguised pursuit of an ethnic/sectional agenda, b) a 'minority rights' project, and c) a minority province’s protest against 'selective' environmental 'victimisation' by the majority ethnic nationalities. While the dominant scholarly analyses of the struggles are based on the activities of the better known activist organisations operating in the oil region, this thesis focuses primarily on the everyday 'grammar' of discontent and lived worlds of ordinary people vis-à-vis upstream petroleum operations and petroleum resource utilisation. The aim has been to gain an understanding of the forces driving community struggles in the oil region and their wider societal significance. Examined alongside the narratives of ordinary people are the legal/institutional framework for upstream petroleum operations and the operational practices of the oil-producing companies. Using primary data obtained through ethnography, focus group discussions, in-depth interviews and visual sociology, as well as relevant secondary data, the researcher constructs a discourse matrix, showing how grassroots narratives in selected oilproducing communities intersect with contemporary civic discourses in the wider Nigerian context. The thesis highlights the theoretical and policy difficulties that arise when the social basis of petroleum-related grassroots struggles and ordinary people’s narratives are explained using an essentialist idiom. It reveals, above all, the conditions under which so-called 'locale-specific' struggles in a multi-ethnic, oil-rich African country can become a campaign for the emancipation of ordinary people in the wider society. This research extends the existing knowledge on citizen mobilisation, extractive capitalism, transnational corporate behaviour, and Nigeria’s contemporary development predicament. It sheds light on some of the processes through which ordinary people are forcing upon the state a change agenda that could drive the country along a more socially sensitive development and democratisation trajectory.
- Full Text:
- Date Issued: 2006
- Authors: Akpan, Wilson Ndarake
- Date: 2006
- Subjects: Petroleum industry and trade -- Nigeria Revenue -- Nigeria Nigeria -- Social conditions Nigeria -- Economic conditions Niger River Delta (Nigeria) -- Environmental conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3294 , http://hdl.handle.net/10962/d1003082
- Description: This thesis examines the social character of petroleum-related grassroots struggles in Nigeria’s oil-producing region. It does this against the background of the dominant scholarly narratives that portray the struggles as: a) a disguised pursuit of an ethnic/sectional agenda, b) a 'minority rights' project, and c) a minority province’s protest against 'selective' environmental 'victimisation' by the majority ethnic nationalities. While the dominant scholarly analyses of the struggles are based on the activities of the better known activist organisations operating in the oil region, this thesis focuses primarily on the everyday 'grammar' of discontent and lived worlds of ordinary people vis-à-vis upstream petroleum operations and petroleum resource utilisation. The aim has been to gain an understanding of the forces driving community struggles in the oil region and their wider societal significance. Examined alongside the narratives of ordinary people are the legal/institutional framework for upstream petroleum operations and the operational practices of the oil-producing companies. Using primary data obtained through ethnography, focus group discussions, in-depth interviews and visual sociology, as well as relevant secondary data, the researcher constructs a discourse matrix, showing how grassroots narratives in selected oilproducing communities intersect with contemporary civic discourses in the wider Nigerian context. The thesis highlights the theoretical and policy difficulties that arise when the social basis of petroleum-related grassroots struggles and ordinary people’s narratives are explained using an essentialist idiom. It reveals, above all, the conditions under which so-called 'locale-specific' struggles in a multi-ethnic, oil-rich African country can become a campaign for the emancipation of ordinary people in the wider society. This research extends the existing knowledge on citizen mobilisation, extractive capitalism, transnational corporate behaviour, and Nigeria’s contemporary development predicament. It sheds light on some of the processes through which ordinary people are forcing upon the state a change agenda that could drive the country along a more socially sensitive development and democratisation trajectory.
- Full Text:
- Date Issued: 2006
Biocultural diversity: moving beyond the realm of ‘indigenous’ and ‘local’ people
- Authors: Cocks, Michelle L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7107 , http://hdl.handle.net/10962/d1010681
- Description: During the past decade the relationship between biodiversity and human diversity has received increased attention, resulting in the identification of what the Declaration of Belém calls an ‘inextricable link’ between biological and cultural diversity. Although the term biocultural diversity, introduced to denote this link, is being used increasingly, there has been little critical reflection on what it precisely refers to. I argue that it is used with particular reference to ‘indigenous traditional’ people, but that there is scope for extending its application within biocultural discourse. I therefore review the concept of culture and discuss what constitutes cultural values of the natural environment. I conclude that the concept of culture must be understood as involving a dynamic process of transcultural exchange and constant re-articulations of tradition resulting in the persistence of certain cultural practices. This approach ultimately reveals that the concept of biocultural diversity is also applicable to non-indigenous traditional communities.
- Full Text:
- Date Issued: 2006
- Authors: Cocks, Michelle L
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:7107 , http://hdl.handle.net/10962/d1010681
- Description: During the past decade the relationship between biodiversity and human diversity has received increased attention, resulting in the identification of what the Declaration of Belém calls an ‘inextricable link’ between biological and cultural diversity. Although the term biocultural diversity, introduced to denote this link, is being used increasingly, there has been little critical reflection on what it precisely refers to. I argue that it is used with particular reference to ‘indigenous traditional’ people, but that there is scope for extending its application within biocultural discourse. I therefore review the concept of culture and discuss what constitutes cultural values of the natural environment. I conclude that the concept of culture must be understood as involving a dynamic process of transcultural exchange and constant re-articulations of tradition resulting in the persistence of certain cultural practices. This approach ultimately reveals that the concept of biocultural diversity is also applicable to non-indigenous traditional communities.
- Full Text:
- Date Issued: 2006
Bioequivalence assessment of generic products an innovative South African approach
- Walker, Roderick B, Kanfer, Isadore, Skinner, Michael F
- Authors: Walker, Roderick B , Kanfer, Isadore , Skinner, Michael F
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184256 , vital:44194 , xlink:href="https://doi.org/10.1080/10601330500534014"
- Description: Concurrent with the implementation of new legislation mandating Generic Substitution in South Africa, a new set of guidelines for bioavailability and bioequivalence have been published. Since one of the main objectives of the new legislation in South Africa relating to Generic Substitution is to ensure that medicines of high quality, safety, and efficacy are made more accessible and more affordable to the wider public, the need to speed up approval of such multi-source products has become a regulatory priority. In order to facilitate this process, various bioequivalence issues have been addressed including important issues such as the acceptance criteria and associated bioequivalence intervals, use of a foreign reference product and the issue of assessing highly variable drugs (HVDs). In addition, dispensations have been made with respect to food effect assessment and variability relating to genetic polymorphism in drug metabolism (genotyping/phenotyping). Furthermore, the use of “old” biostudies submitted in support of an application is subject to expiry date. Acceptance of appropriate data requires that specific criteria such as Cmax and AUC, in addition to the usual considerations, also meet the limits specified by the particular registration authority of the country where such products are intended to be marketed. Generally, these limits require that the 90% confidence interval (CI) for AUC and Cmax test/reference ratios lies within the acceptance interval of 0.80–1.25 calculated using log-transformed data. While such acceptance criteria are, in general, ubiquitous, some differences in acceptance criteria do exist between various countries. The new guidelines for bioavailability/bioequivalence studies developed by the South African regulatory authority, the Medicines Control Council (MCC), makes provision for highly variable drugs and the use of a non-South African reference product. The MCC requires that the acceptance criterion for Cmax ratios be set at 0.75–1.33 while maintaining AUC ratios at 0.80–1.25 using a 90% CI. Furthermore, provision is made to apply scaling based on average bioequivalence assessment and, as an interim measure, consideration has also been given to the use of a foreign reference product provided that equivalence between that product and the innovator product currently available on the South African market can be shown using in vitro testing.
- Full Text:
- Date Issued: 2006
- Authors: Walker, Roderick B , Kanfer, Isadore , Skinner, Michael F
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184256 , vital:44194 , xlink:href="https://doi.org/10.1080/10601330500534014"
- Description: Concurrent with the implementation of new legislation mandating Generic Substitution in South Africa, a new set of guidelines for bioavailability and bioequivalence have been published. Since one of the main objectives of the new legislation in South Africa relating to Generic Substitution is to ensure that medicines of high quality, safety, and efficacy are made more accessible and more affordable to the wider public, the need to speed up approval of such multi-source products has become a regulatory priority. In order to facilitate this process, various bioequivalence issues have been addressed including important issues such as the acceptance criteria and associated bioequivalence intervals, use of a foreign reference product and the issue of assessing highly variable drugs (HVDs). In addition, dispensations have been made with respect to food effect assessment and variability relating to genetic polymorphism in drug metabolism (genotyping/phenotyping). Furthermore, the use of “old” biostudies submitted in support of an application is subject to expiry date. Acceptance of appropriate data requires that specific criteria such as Cmax and AUC, in addition to the usual considerations, also meet the limits specified by the particular registration authority of the country where such products are intended to be marketed. Generally, these limits require that the 90% confidence interval (CI) for AUC and Cmax test/reference ratios lies within the acceptance interval of 0.80–1.25 calculated using log-transformed data. While such acceptance criteria are, in general, ubiquitous, some differences in acceptance criteria do exist between various countries. The new guidelines for bioavailability/bioequivalence studies developed by the South African regulatory authority, the Medicines Control Council (MCC), makes provision for highly variable drugs and the use of a non-South African reference product. The MCC requires that the acceptance criterion for Cmax ratios be set at 0.75–1.33 while maintaining AUC ratios at 0.80–1.25 using a 90% CI. Furthermore, provision is made to apply scaling based on average bioequivalence assessment and, as an interim measure, consideration has also been given to the use of a foreign reference product provided that equivalence between that product and the innovator product currently available on the South African market can be shown using in vitro testing.
- Full Text:
- Date Issued: 2006
Biogeographic and nearshore–offshore trends in isotope ratios of intertidal mussels and their food sources around the coast of southern Africa
- Hill, Jaclyn M, McQuaid, Christopher D, Kaehler, Sven
- Authors: Hill, Jaclyn M , McQuaid, Christopher D , Kaehler, Sven
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6878 , http://hdl.handle.net/10962/d1011633
- Description: There are broad differences in oceanography and primary production around the southern African coast that are likely to give rise to major differences in trophic pathways. Stable isotope ratios provide integrated information on trophic relationships, yet there has been limited research on geographic variation in isotopic composition of marine consumers and their food. In this study, δ13C and δ15N of suspended particulate matter (SPM), intertidal mussels and common macroalgae along the southern African coastline were explored. Nearshore–offshore isotope trends as well as biogeographic and temporal patterns in isotopic ratios of mussel tissue, macroalgae and SPM were investigated at 12 sites along the coast from Namibia to the Mozambique border. SPM exhibited overall trends of nearshore 13C depletion from south-west to north-east along the coastline and from nearshore (0 km) to offshore (10 km) waters, in both cases suggesting a shift from a nearshore signature strongly influenced by macroalgal detritus to one more representative of oceanic phytoplankton. With one exception it was possible, using discriminant analysis, to categorize mussel populations into 4 geographic groups, on the basis of both carbon and nitrogen signatures: the east coast, the south-east coast, the south-west coast and the west coast. Macroalgae showed no consistent biogeographic trends and need to be examined in greater detail to relate nearshore SPM values to living macroalgal signatures. A linear mixing model indicated that mussels along the entire coastline generally demonstrated more than 50% dependence on nearshore carbon and nitrogen, emphasizing the importance of nearshore primary production to intertidal consumers.
- Full Text:
- Date Issued: 2006
- Authors: Hill, Jaclyn M , McQuaid, Christopher D , Kaehler, Sven
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6878 , http://hdl.handle.net/10962/d1011633
- Description: There are broad differences in oceanography and primary production around the southern African coast that are likely to give rise to major differences in trophic pathways. Stable isotope ratios provide integrated information on trophic relationships, yet there has been limited research on geographic variation in isotopic composition of marine consumers and their food. In this study, δ13C and δ15N of suspended particulate matter (SPM), intertidal mussels and common macroalgae along the southern African coastline were explored. Nearshore–offshore isotope trends as well as biogeographic and temporal patterns in isotopic ratios of mussel tissue, macroalgae and SPM were investigated at 12 sites along the coast from Namibia to the Mozambique border. SPM exhibited overall trends of nearshore 13C depletion from south-west to north-east along the coastline and from nearshore (0 km) to offshore (10 km) waters, in both cases suggesting a shift from a nearshore signature strongly influenced by macroalgal detritus to one more representative of oceanic phytoplankton. With one exception it was possible, using discriminant analysis, to categorize mussel populations into 4 geographic groups, on the basis of both carbon and nitrogen signatures: the east coast, the south-east coast, the south-west coast and the west coast. Macroalgae showed no consistent biogeographic trends and need to be examined in greater detail to relate nearshore SPM values to living macroalgal signatures. A linear mixing model indicated that mussels along the entire coastline generally demonstrated more than 50% dependence on nearshore carbon and nitrogen, emphasizing the importance of nearshore primary production to intertidal consumers.
- Full Text:
- Date Issued: 2006
Biomonitoring in two contrasting catchments
- Authors: Maseti, Pumza Penelope
- Date: 2006
- Subjects: Water quality biological assessment -- South Africa , Water quality management -- South Africa , Rivers -- South Africa , Freshwater fishes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6034 , http://hdl.handle.net/10962/d1006175 , Water quality biological assessment -- South Africa , Water quality management -- South Africa , Rivers -- South Africa , Freshwater fishes -- South Africa
- Description: The introduction of instream biological monitoring to water resources management has been an increasing trend world-wide. This monitoring uses biological field assessments of instream biota such as macroinvertebrates, fish and riparian vegetation as an integrated and sensitive tool for diagnosing the condition of the ecosystems and assessing ecological impacts. Biomonitoring information has become an important component in the overall assessment of water resources and is used to drive and direct processes of decision-making and management of water resources. The River Health Programme (RHP) was initiated in South Africa to serve as a source of information regarding the ecological status of river systems, in order to support rational management of these natural resources. In this study, biomonitoring indices (SASS5 and FAII) were used to assess the present ecological status of two rivers located in contrasting catchments of the Eastern Cape. The first river is the Buffalo River located in an urban and industrialized catchment. The second river is the Inxu River draining a rural and afforested catchment. SASS5 was used successfully in both rivers and the results based on water quality and SASS5 indicated that most sites selected on the upper catchment of the Buffalo River have a fair water quality with most sites selected on the lower catchment having a poor water quality. The Inxu River sites (both upper and lower catchment) based on SASS5 and water quality results have a good to fair water quality. The majority of sites sampled on both rivers systems had very low FAII scores and fell within a critically modified water quality category. This result may be due to the fact that these rivers have low fish diversities (either low natural diversity or low diversity due to the presence of alien fish species), poor water quality or inadequate sampling methods. Observations from this study suggest that this index may not be suitable for rivers with low fish diversity. A fish index that is usable to all ecoregions of South Africa with minor adaptations to suit local conditions is still needed, as the present FAII index does not meet these requirements.
- Full Text:
- Date Issued: 2006
- Authors: Maseti, Pumza Penelope
- Date: 2006
- Subjects: Water quality biological assessment -- South Africa , Water quality management -- South Africa , Rivers -- South Africa , Freshwater fishes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:6034 , http://hdl.handle.net/10962/d1006175 , Water quality biological assessment -- South Africa , Water quality management -- South Africa , Rivers -- South Africa , Freshwater fishes -- South Africa
- Description: The introduction of instream biological monitoring to water resources management has been an increasing trend world-wide. This monitoring uses biological field assessments of instream biota such as macroinvertebrates, fish and riparian vegetation as an integrated and sensitive tool for diagnosing the condition of the ecosystems and assessing ecological impacts. Biomonitoring information has become an important component in the overall assessment of water resources and is used to drive and direct processes of decision-making and management of water resources. The River Health Programme (RHP) was initiated in South Africa to serve as a source of information regarding the ecological status of river systems, in order to support rational management of these natural resources. In this study, biomonitoring indices (SASS5 and FAII) were used to assess the present ecological status of two rivers located in contrasting catchments of the Eastern Cape. The first river is the Buffalo River located in an urban and industrialized catchment. The second river is the Inxu River draining a rural and afforested catchment. SASS5 was used successfully in both rivers and the results based on water quality and SASS5 indicated that most sites selected on the upper catchment of the Buffalo River have a fair water quality with most sites selected on the lower catchment having a poor water quality. The Inxu River sites (both upper and lower catchment) based on SASS5 and water quality results have a good to fair water quality. The majority of sites sampled on both rivers systems had very low FAII scores and fell within a critically modified water quality category. This result may be due to the fact that these rivers have low fish diversities (either low natural diversity or low diversity due to the presence of alien fish species), poor water quality or inadequate sampling methods. Observations from this study suggest that this index may not be suitable for rivers with low fish diversity. A fish index that is usable to all ecoregions of South Africa with minor adaptations to suit local conditions is still needed, as the present FAII index does not meet these requirements.
- Full Text:
- Date Issued: 2006
Blogging, journalism and the public sphere: assessing the value of the 'blogosphere' as a new form of the public sphere : a case study of the Mail & Guardian Online's Blogmark
- Authors: Sibanda, Fortune
- Date: 2006
- Subjects: Habermas, Jürgen -- Criticism and interpretation , Mail & Guardian , Blogs -- South Africa , Online journalism -- South Africa , Electronic newspapers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3483 , http://hdl.handle.net/10962/d1002938 , Habermas, Jürgen -- Criticism and interpretation , Mail & Guardian , Blogs -- South Africa , Online journalism -- South Africa , Electronic newspapers -- South Africa
- Description: The study seeks to investigate whether weblogs can act as virtual public spheres, where people can meet to discuss issues of interest to them. It uses the Mail & Guardian Online’s Blogmark as a case study. Weblogs – highly interactive online journals comprised of links and postings in reverse chronological order – are fast becoming an avenue of choice for many internet users wanting to share opinions and news with others online. Because of their unique read-and-write characteristics, some have equated them to the 18th century coffeehouses, around which the early forms of citizen involvement in public affairs began in early capitalist Europe. Despite their growing popularity, however, not much scholarly work has been dedicated to the practice of blogging in Africa, and particularly in South Africa. The study’s theoretical framework is drawn from Jürgen Habermas’s concept of the public sphere. While noting some of the criticisms of the Habermasian model, it is argued that the concept is instrumental in our understanding of the relationship between the media and democracy. The study, however, adopted a re-worked model of the concept of the public sphere. This model argues for the need to have a multiplicity of public sphericules (instead of one single public sphere as advocated by Habermas), around which individuals can congregate to discuss issues of common concern to them. Using a combination of qualitative content analysis, self-completion questionnaires and a semi-structured interview, the study found Blogmark to be an example of how emerging internet genres such as weblogs can be vehicles of citizen involvement in public life. A range of issues were discussed in the blog, from politics, race and ii i gender issues, to personal anecdotes, relationships, and sex. However, while some posts exhibited high levels of interactivity, with many bloggers joining in to offer their opinions, some read like online monologues. The study argues that although blogging is a practice that is still limited to a few privileged individuals, with the everrising size of the ‘blogosphere’, weblogs such as Blogmark are making a small but not insignificant contribution to the number of voices that can be heard in the public realm.
- Full Text:
- Date Issued: 2006
- Authors: Sibanda, Fortune
- Date: 2006
- Subjects: Habermas, Jürgen -- Criticism and interpretation , Mail & Guardian , Blogs -- South Africa , Online journalism -- South Africa , Electronic newspapers -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3483 , http://hdl.handle.net/10962/d1002938 , Habermas, Jürgen -- Criticism and interpretation , Mail & Guardian , Blogs -- South Africa , Online journalism -- South Africa , Electronic newspapers -- South Africa
- Description: The study seeks to investigate whether weblogs can act as virtual public spheres, where people can meet to discuss issues of interest to them. It uses the Mail & Guardian Online’s Blogmark as a case study. Weblogs – highly interactive online journals comprised of links and postings in reverse chronological order – are fast becoming an avenue of choice for many internet users wanting to share opinions and news with others online. Because of their unique read-and-write characteristics, some have equated them to the 18th century coffeehouses, around which the early forms of citizen involvement in public affairs began in early capitalist Europe. Despite their growing popularity, however, not much scholarly work has been dedicated to the practice of blogging in Africa, and particularly in South Africa. The study’s theoretical framework is drawn from Jürgen Habermas’s concept of the public sphere. While noting some of the criticisms of the Habermasian model, it is argued that the concept is instrumental in our understanding of the relationship between the media and democracy. The study, however, adopted a re-worked model of the concept of the public sphere. This model argues for the need to have a multiplicity of public sphericules (instead of one single public sphere as advocated by Habermas), around which individuals can congregate to discuss issues of common concern to them. Using a combination of qualitative content analysis, self-completion questionnaires and a semi-structured interview, the study found Blogmark to be an example of how emerging internet genres such as weblogs can be vehicles of citizen involvement in public life. A range of issues were discussed in the blog, from politics, race and ii i gender issues, to personal anecdotes, relationships, and sex. However, while some posts exhibited high levels of interactivity, with many bloggers joining in to offer their opinions, some read like online monologues. The study argues that although blogging is a practice that is still limited to a few privileged individuals, with the everrising size of the ‘blogosphere’, weblogs such as Blogmark are making a small but not insignificant contribution to the number of voices that can be heard in the public realm.
- Full Text:
- Date Issued: 2006