Water resources management and its impact on small scale farming :the case of Lesotho
- Authors: Malinga, Wayne
- Date: 2018
- Subjects: Water resources development -- Lesotho Water-supply -- Lesotho Farms, Small -- Lesotho
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9089 , vital:34256
- Description: This study is premised on the assumption that empowering the small-scale farmers in securing property rights and enforcement of these rights are the prime movers of agricultural development. Logically, it follows that by empowering small-scale farmers and giving them access to resources such as credits, subsidies and extension services the state can play a mediating role in transforming the agricultural land scape in Lesotho. Unless farmers are empowered the water resources in Lesotho will continue to serve the interest of the rent-seeking elite. Given the nature of the issues under investigation, the mixed research methodology (the use of both qualitative and quantitative methods) was used as a method of inquiry in order to get a deeper understanding of the phenomenon of water resources management and its subsequent impact on small scale farming in the rural areas of Lesotho. Both methods played a complimentary role by capitalising on both their strengths and weaknesses so as to provide various dynamics and linkages between the two variables of water resources management and small scale farming. The material condition of small scale farmers is intrinsically associated with the active state mediation in agriculture. Yet, the adopted Integrated Water Resources Management (IWRM) approach is still to materialise. This thesis, thus, argues that there is a need for a more holistic integrated water resources management framework that is livelihoods based and re-emphasises the need for conserving the ecosystem. Therefore, implementing a more holistic integrated water resources management approach is critical and vital in improving agricultural production and subsequently the livelihoods of small scale farmers and households. Although this thesis used Lesotho as the case study, it is hoped that the findings may provide tentative answers for other Sub-Saharan countries on how to properly and efficiently manage water resources so as to boost agricultural production amongst small scale farmers in order to improve human conditions and promote sustainable development in the rural areas.
- Full Text:
- Date Issued: 2018
- Authors: Malinga, Wayne
- Date: 2018
- Subjects: Water resources development -- Lesotho Water-supply -- Lesotho Farms, Small -- Lesotho
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/9089 , vital:34256
- Description: This study is premised on the assumption that empowering the small-scale farmers in securing property rights and enforcement of these rights are the prime movers of agricultural development. Logically, it follows that by empowering small-scale farmers and giving them access to resources such as credits, subsidies and extension services the state can play a mediating role in transforming the agricultural land scape in Lesotho. Unless farmers are empowered the water resources in Lesotho will continue to serve the interest of the rent-seeking elite. Given the nature of the issues under investigation, the mixed research methodology (the use of both qualitative and quantitative methods) was used as a method of inquiry in order to get a deeper understanding of the phenomenon of water resources management and its subsequent impact on small scale farming in the rural areas of Lesotho. Both methods played a complimentary role by capitalising on both their strengths and weaknesses so as to provide various dynamics and linkages between the two variables of water resources management and small scale farming. The material condition of small scale farmers is intrinsically associated with the active state mediation in agriculture. Yet, the adopted Integrated Water Resources Management (IWRM) approach is still to materialise. This thesis, thus, argues that there is a need for a more holistic integrated water resources management framework that is livelihoods based and re-emphasises the need for conserving the ecosystem. Therefore, implementing a more holistic integrated water resources management approach is critical and vital in improving agricultural production and subsequently the livelihoods of small scale farmers and households. Although this thesis used Lesotho as the case study, it is hoped that the findings may provide tentative answers for other Sub-Saharan countries on how to properly and efficiently manage water resources so as to boost agricultural production amongst small scale farmers in order to improve human conditions and promote sustainable development in the rural areas.
- Full Text:
- Date Issued: 2018
Fundamental investigations into the factors affecting the response of laccase-based electrochemical biosensors
- Authors: Fogel, Ronen
- Date: 2011
- Subjects: Laccase Phenols Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4073 , http://hdl.handle.net/10962/d1007166
- Description: Given their widespread effects and distribution in both natural and industrial environments, the monitoring of phenolic compounds is of considerable analytical interest. Electrochemical biosensor technologies, in particular those comprising laccase enzymes, afford many potential benefits to address this analytical need. However, several key factors affecting sensor response currently limit their applicability. This Thesis reports on the fabrication and optimisation of an electrochemical laccase-based biosensor towards the application of the monitoring of phenolic compounds. Selected factors considered to affect sensor response were investigated using the optimised biosensor. These included: electrochemical, biochemical and substrate-dependent factors, which were found to intersect in modulating biosensor response signals. Through the application of transducer-dependent and substrate-dependent parameters, the selective and simultaneous detection of a mixture of different phenolic analytes is successfully demonstrated. This Thesis also investigates the use of Quartz-Crystal Microbalance with Dissipation (QCM-D) technology, an analytical technique that measures physical parameters of thin-film structures, towards the successful monitoring of enzyme immobilisation strategies. These strategies are fundamental to the successful fabrication of biosensors, and the real-time monitoring of immobilised film formations is of considerable research interest. In the studies reported on in this Thesis, QCM-D technology was demonstrated to be an effective complementary technology in the prediction of film immobilisation techniques on the resultant biochemical kinetics of immobilised enzymes.
- Full Text:
- Date Issued: 2011
- Authors: Fogel, Ronen
- Date: 2011
- Subjects: Laccase Phenols Biosensors
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4073 , http://hdl.handle.net/10962/d1007166
- Description: Given their widespread effects and distribution in both natural and industrial environments, the monitoring of phenolic compounds is of considerable analytical interest. Electrochemical biosensor technologies, in particular those comprising laccase enzymes, afford many potential benefits to address this analytical need. However, several key factors affecting sensor response currently limit their applicability. This Thesis reports on the fabrication and optimisation of an electrochemical laccase-based biosensor towards the application of the monitoring of phenolic compounds. Selected factors considered to affect sensor response were investigated using the optimised biosensor. These included: electrochemical, biochemical and substrate-dependent factors, which were found to intersect in modulating biosensor response signals. Through the application of transducer-dependent and substrate-dependent parameters, the selective and simultaneous detection of a mixture of different phenolic analytes is successfully demonstrated. This Thesis also investigates the use of Quartz-Crystal Microbalance with Dissipation (QCM-D) technology, an analytical technique that measures physical parameters of thin-film structures, towards the successful monitoring of enzyme immobilisation strategies. These strategies are fundamental to the successful fabrication of biosensors, and the real-time monitoring of immobilised film formations is of considerable research interest. In the studies reported on in this Thesis, QCM-D technology was demonstrated to be an effective complementary technology in the prediction of film immobilisation techniques on the resultant biochemical kinetics of immobilised enzymes.
- Full Text:
- Date Issued: 2011
Biocatalytic and biomimetic studies of polyphenol oxidase
- Authors: Burton, Stephanie Gail
- Date: 1994
- Subjects: Phenol oxidase Polyphenols Oxidases
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4028 , http://hdl.handle.net/10962/d1004088
- Description: Mushroom polyphenol oxidase (EC 1.14.18.1) was investigated to determine its potential for application as a biocatalyst in the synthesis of o-quinones, in organic medium. In order to determine the kinetic properties of the biocatalyst, a system was devised which comprised an immobilised polyphenol oxidase extract, functioning in chloroform. The system was hydrated by the addition of buffer. A simple method for the consistent measurement of reaction rates in this heterogenous system was designed and used to obtain detailed enzyme kinetic data relating to optimisation of reaction conditions and substrate specificity. The aqueous content of the system was optimised using p-cresol as a substrate. A crude, immobilised extract of Agaricus bisporus was used to hydroxylate and oxidise a range of selected p-substituted phenolic substrates, yielding, as the sale products, o-quinones. These products were efficiently reduced to catechols by extracting the reaction mixtures with aqueous ascorbic acid solution. The biocatalytic system was also successfully utilised to produce L-DOPA, the drug used to treat Parkinson's disease, from L-acetyl tyrosine ethyl ester (ATEE). Michaelis-Menten kinetics were used to obtain apparent Km and V values with respect to the selected phenolic substrates, and the kinetic parameters obtained were found to correlate well with the steric requirements of the substrates and with their hydrophobicity. In the course of the investigation, a novel ¹H NMR method was used to facilitate measurement of the UV molar absorption coefficients of the o-quinones in reaction mixtures, thus avoiding the necessity to isolate these unstable, water-sensitive products. The biocatalytic system was extended to a continuous process, in which the immobilised enzyme was shown to function successfully in the chloroform medium for several hours, with high conversion rates. Modifications, involving partial purification and the addition of a surfactant, were investigated to determine their effect on the kinetic parameters. The results obtained using partially purified enzyme indicated that the removal of extraneous protein and/or melanoid material lead to a reduced capacity for conversion of sterically demanding substrates. The addition of the anionic detergent, sodium dodecyl sulphate (SOS), enhanced the ability of the biocatalyst to bind and oxidise sterically demanding substrates. These effects are attributed to changes in the polar state of groups within the protein binding pocket, which result in altered flexibility and hydrophobicity. Computer modelling of several biomimetic dinuclear copper complexes also indicated the importance of flexibility for effective biocatalysis. Novel binuclear copper (II complexes, containing a flexible biphenyl spacer and imidazole or benzimidazole donors, were prepared and analysed using NMR, UV, AA and cyclic voltammetric techniques. The complexes were also shown, in a detailed kinetic study, to mimic the catecholase activity of polyphenol oxidase by oxidising 3,5-di-tertbutylcatechol, and to catalyse the coupling of the phenolic substrate 2,4-di-tert-butylphenol. However, the complexes were apparently too flexible to react with smaller substrates. These biomimetic complexes provided valuable insights into the nature of the dinuclear copper binding site.
- Full Text:
- Date Issued: 1994
- Authors: Burton, Stephanie Gail
- Date: 1994
- Subjects: Phenol oxidase Polyphenols Oxidases
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4028 , http://hdl.handle.net/10962/d1004088
- Description: Mushroom polyphenol oxidase (EC 1.14.18.1) was investigated to determine its potential for application as a biocatalyst in the synthesis of o-quinones, in organic medium. In order to determine the kinetic properties of the biocatalyst, a system was devised which comprised an immobilised polyphenol oxidase extract, functioning in chloroform. The system was hydrated by the addition of buffer. A simple method for the consistent measurement of reaction rates in this heterogenous system was designed and used to obtain detailed enzyme kinetic data relating to optimisation of reaction conditions and substrate specificity. The aqueous content of the system was optimised using p-cresol as a substrate. A crude, immobilised extract of Agaricus bisporus was used to hydroxylate and oxidise a range of selected p-substituted phenolic substrates, yielding, as the sale products, o-quinones. These products were efficiently reduced to catechols by extracting the reaction mixtures with aqueous ascorbic acid solution. The biocatalytic system was also successfully utilised to produce L-DOPA, the drug used to treat Parkinson's disease, from L-acetyl tyrosine ethyl ester (ATEE). Michaelis-Menten kinetics were used to obtain apparent Km and V values with respect to the selected phenolic substrates, and the kinetic parameters obtained were found to correlate well with the steric requirements of the substrates and with their hydrophobicity. In the course of the investigation, a novel ¹H NMR method was used to facilitate measurement of the UV molar absorption coefficients of the o-quinones in reaction mixtures, thus avoiding the necessity to isolate these unstable, water-sensitive products. The biocatalytic system was extended to a continuous process, in which the immobilised enzyme was shown to function successfully in the chloroform medium for several hours, with high conversion rates. Modifications, involving partial purification and the addition of a surfactant, were investigated to determine their effect on the kinetic parameters. The results obtained using partially purified enzyme indicated that the removal of extraneous protein and/or melanoid material lead to a reduced capacity for conversion of sterically demanding substrates. The addition of the anionic detergent, sodium dodecyl sulphate (SOS), enhanced the ability of the biocatalyst to bind and oxidise sterically demanding substrates. These effects are attributed to changes in the polar state of groups within the protein binding pocket, which result in altered flexibility and hydrophobicity. Computer modelling of several biomimetic dinuclear copper complexes also indicated the importance of flexibility for effective biocatalysis. Novel binuclear copper (II complexes, containing a flexible biphenyl spacer and imidazole or benzimidazole donors, were prepared and analysed using NMR, UV, AA and cyclic voltammetric techniques. The complexes were also shown, in a detailed kinetic study, to mimic the catecholase activity of polyphenol oxidase by oxidising 3,5-di-tertbutylcatechol, and to catalyse the coupling of the phenolic substrate 2,4-di-tert-butylphenol. However, the complexes were apparently too flexible to react with smaller substrates. These biomimetic complexes provided valuable insights into the nature of the dinuclear copper binding site.
- Full Text:
- Date Issued: 1994
Nepticulidae (Lepidoptera) : a revised classification, and descriptions of some new taxa particularly from southern Africa
- Authors: Scoble, M J
- Date: 1982
- Subjects: Nepticulidae Nepticulidae--Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5801 , http://hdl.handle.net/10962/d1006183
- Description: Previous classifications of the Nepticulidae were based on species from the northern hemisphere, primarily western Europe (including the United Kingdom) and North America. The revised classification presented in the present work was developed from a study of material primarily from southern Africa, but also from Australia, Europe, North America, and the Orient. Most of the descriptive section deals with the taxonomy of the Nepticulidae of southern Africa. Nevertheless, a guide to the supraspecific classification of the family was a major aim. Cladistic methods were used to assess genealogy as far as possible. The degree to which it has been elucidated is incorporated into the classification. As a result of the study, the Nepticulidae are divided into two subfamilies. One of these subfamilies is divided into two tribes. Fifteen genera and six subgenera are recognised. Two keys are presented, one to subfamilies and tribes and the other to genera and subgenera. The species from southern Africa are included in eight genera, three of which are new. One hundred and seventeen species from southern Africa are considered. Seventy- two new species are described in this work. Of these 40 have been published and 32 appear as manuscript names. For some species described by previous workers lectotypes have been designated where appropriate. The primary types of all the known species from southern Africa have been examined. Observations on adult structure are discussed from the viewpoint of phylogenetic relationships both within the Nepticulidae and between the family and other lepidopteran groups. This has led to a re-interpretation and expansion of some aspects of nepticulid morphology. Numerical phenetic methods, which include cluster analyses and an ordination technique (principal component analysis), were used to check my personal assessment of phena. The illustrations (phenograms and ordination diagrams) provide a visual summary of phenetic relationships of as wide a range of Nepticulidae as possible. Aspects of the nature of taxonomic characters, ancestor-descendant relationships, and homoplasy are discussed. Brief comments are made on distribution, and host-plant choice and phylogeny.
- Full Text:
- Date Issued: 1982
- Authors: Scoble, M J
- Date: 1982
- Subjects: Nepticulidae Nepticulidae--Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5801 , http://hdl.handle.net/10962/d1006183
- Description: Previous classifications of the Nepticulidae were based on species from the northern hemisphere, primarily western Europe (including the United Kingdom) and North America. The revised classification presented in the present work was developed from a study of material primarily from southern Africa, but also from Australia, Europe, North America, and the Orient. Most of the descriptive section deals with the taxonomy of the Nepticulidae of southern Africa. Nevertheless, a guide to the supraspecific classification of the family was a major aim. Cladistic methods were used to assess genealogy as far as possible. The degree to which it has been elucidated is incorporated into the classification. As a result of the study, the Nepticulidae are divided into two subfamilies. One of these subfamilies is divided into two tribes. Fifteen genera and six subgenera are recognised. Two keys are presented, one to subfamilies and tribes and the other to genera and subgenera. The species from southern Africa are included in eight genera, three of which are new. One hundred and seventeen species from southern Africa are considered. Seventy- two new species are described in this work. Of these 40 have been published and 32 appear as manuscript names. For some species described by previous workers lectotypes have been designated where appropriate. The primary types of all the known species from southern Africa have been examined. Observations on adult structure are discussed from the viewpoint of phylogenetic relationships both within the Nepticulidae and between the family and other lepidopteran groups. This has led to a re-interpretation and expansion of some aspects of nepticulid morphology. Numerical phenetic methods, which include cluster analyses and an ordination technique (principal component analysis), were used to check my personal assessment of phena. The illustrations (phenograms and ordination diagrams) provide a visual summary of phenetic relationships of as wide a range of Nepticulidae as possible. Aspects of the nature of taxonomic characters, ancestor-descendant relationships, and homoplasy are discussed. Brief comments are made on distribution, and host-plant choice and phylogeny.
- Full Text:
- Date Issued: 1982
Die sielkundige aanpassing van drie groepe Bantoes volgens die Rorschach toets
- Authors: Du Preez, Pieter Hendrik
- Date: 1968
- Subjects: Rorschach test Black people -- South Africa -- Psychology Ethnopsychology
- Language: Afrikaans
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3203 , http://hdl.handle.net/10962/d1011495
- Description: Die huidige belangrike rol wat die Bantoe van Afrika in internasionale sake speel, is welbekend. So ook die belangrikheid van die Suid-Afrikaanse Bantoe. Hierdie belangrikheid van die Bantoe het egter verbasend skielik en vinnig gekom, so vinnig dat wetenskaplike kennis van hom as mens, nie kon tred hou nie, met die gevolg dat die beskaafde wereld hom swak ken. Die doel van hierdie proefskrif is dan ook om meer Iig te probeer werp op die persoonlikheid van die Bantoe en die lnvloed wat die snel veranderende omstandighede op hom uitoefen. Ten einde die maksimum waarde uit die Rorschach toets wat aangewend is, te verkry, is dlt nodig om beide die determinants berekenings sowel as die inhoudsanalise in berekening te bring. Vir navorsingsdoeleindes waar die resultate van verskeie proefpersone saamgevoeg word in verskiIlende groepe, is dit egter 'n moelIike taak om die gegewens kwantitatief hanteerbaar te kry. Dit is die rede waarom in hierdie studie van ordeskale gebruik gemaak is wat vir die doel heel doeltreffend blyk te gewees het.
- Full Text:
- Date Issued: 1968
- Authors: Du Preez, Pieter Hendrik
- Date: 1968
- Subjects: Rorschach test Black people -- South Africa -- Psychology Ethnopsychology
- Language: Afrikaans
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3203 , http://hdl.handle.net/10962/d1011495
- Description: Die huidige belangrike rol wat die Bantoe van Afrika in internasionale sake speel, is welbekend. So ook die belangrikheid van die Suid-Afrikaanse Bantoe. Hierdie belangrikheid van die Bantoe het egter verbasend skielik en vinnig gekom, so vinnig dat wetenskaplike kennis van hom as mens, nie kon tred hou nie, met die gevolg dat die beskaafde wereld hom swak ken. Die doel van hierdie proefskrif is dan ook om meer Iig te probeer werp op die persoonlikheid van die Bantoe en die lnvloed wat die snel veranderende omstandighede op hom uitoefen. Ten einde die maksimum waarde uit die Rorschach toets wat aangewend is, te verkry, is dlt nodig om beide die determinants berekenings sowel as die inhoudsanalise in berekening te bring. Vir navorsingsdoeleindes waar die resultate van verskeie proefpersone saamgevoeg word in verskiIlende groepe, is dit egter 'n moelIike taak om die gegewens kwantitatief hanteerbaar te kry. Dit is die rede waarom in hierdie studie van ordeskale gebruik gemaak is wat vir die doel heel doeltreffend blyk te gewees het.
- Full Text:
- Date Issued: 1968
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