Fishing rights, redistribution and policy : the South African commercial T.A.C. fisheries
- Authors: Mather, Diarmid John
- Date: 2005
- Subjects: Fisheries -- South Africa Fish trade -- South Africa Fishery law and legislation -- South Africa Fishery policy -- South Africa Fishery management -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1061 , http://hdl.handle.net/10962/d1007531
- Description: The main objective of this thesis is to provide an analysis of the economic logic behind fisheries policy and redistribution in South African. An examination of the institutional and organizational evolution reveals that South African fisheries policy followed the world trend in the movement toward quota management systems. However, it is argued that due to the peculiarities of the Apartheid political system, South Africa developed a unique and persistent structure of individual fishing rights that resulted in a transfer of power from the fisher to monopsonistic, and subsequently vertically integrated, fish processing companies. Problems, however, arose with the need to redistribute fishing rights to previously repressed racial groups. It is proposed that, within a specific form (TAC), the structure of individual fishing rights can be decomposed into four operational rules, namely, the right of participation, asset size, tradability and duration of term. Policy design is restricted to a feasible set of rules that impact on the flexibility of the system, the incentives facing private fishing companies and fishers, the efficiency of the fisheries management plan and finally the effect it has on a redistribution strategy. Within this analytical framework, South Africa's policy yields a very flexible system favourable to monopsonistic industrial organisation. However, by adding a redistribution constraint, this structure has a number of important effects. First, as new quota holders are added the information costs for effective fisheries management increase exponentially. Second, the transaction costs to private fishing companies are increased. Third, only the resource rent is redistributed (weak redistribution). Next, the micro to small vessel fisheries, the medium vessel fisheries and the large vessel fisheries are examined separately. The major aim is to determine, within the available data, the effect that a weak redistribution policy (redistribution of the resource rent), has on strong redistribution (redistribution of fishing capital and skills). The evidence definitely supports the analytical framework and suggests that fundamentally the structure of individual fishing rights, which evolved in response to a monopsonistic industrial organisation during the apartheid era in South Africa, works against strong redistribution. Also, that different fisheries face different constraints and that these should in certain instances be treated separately.
- Full Text:
- Authors: Mather, Diarmid John
- Date: 2005
- Subjects: Fisheries -- South Africa Fish trade -- South Africa Fishery law and legislation -- South Africa Fishery policy -- South Africa Fishery management -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1061 , http://hdl.handle.net/10962/d1007531
- Description: The main objective of this thesis is to provide an analysis of the economic logic behind fisheries policy and redistribution in South African. An examination of the institutional and organizational evolution reveals that South African fisheries policy followed the world trend in the movement toward quota management systems. However, it is argued that due to the peculiarities of the Apartheid political system, South Africa developed a unique and persistent structure of individual fishing rights that resulted in a transfer of power from the fisher to monopsonistic, and subsequently vertically integrated, fish processing companies. Problems, however, arose with the need to redistribute fishing rights to previously repressed racial groups. It is proposed that, within a specific form (TAC), the structure of individual fishing rights can be decomposed into four operational rules, namely, the right of participation, asset size, tradability and duration of term. Policy design is restricted to a feasible set of rules that impact on the flexibility of the system, the incentives facing private fishing companies and fishers, the efficiency of the fisheries management plan and finally the effect it has on a redistribution strategy. Within this analytical framework, South Africa's policy yields a very flexible system favourable to monopsonistic industrial organisation. However, by adding a redistribution constraint, this structure has a number of important effects. First, as new quota holders are added the information costs for effective fisheries management increase exponentially. Second, the transaction costs to private fishing companies are increased. Third, only the resource rent is redistributed (weak redistribution). Next, the micro to small vessel fisheries, the medium vessel fisheries and the large vessel fisheries are examined separately. The major aim is to determine, within the available data, the effect that a weak redistribution policy (redistribution of the resource rent), has on strong redistribution (redistribution of fishing capital and skills). The evidence definitely supports the analytical framework and suggests that fundamentally the structure of individual fishing rights, which evolved in response to a monopsonistic industrial organisation during the apartheid era in South Africa, works against strong redistribution. Also, that different fisheries face different constraints and that these should in certain instances be treated separately.
- Full Text:
Formulation and assessment of verapamil sustained release tablets
- Khamanga, Sandile Maswazi Malungelo
- Authors: Khamanga, Sandile Maswazi Malungelo
- Date: 2005
- Subjects: Verapamil , Tablets (Medicine) , Drugs -- Administration , Cardiovascular agents , Calcium -- Antagonists , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3869 , http://hdl.handle.net/10962/d1018236
- Description: The oral route of drug administration is most extensively used due to the obvious ease of administration. Verapamil hydrochloride is a WHO listed phenylalkylarnine, L-type calcium channel antagonist that is mainly indicated for cardiovascular disorders such as angina pectoris, supraventricular tachycardia and hypertension. Due to its relatively short half-life of approximately 4.0 hours, the formulation of a sustained-release dosage form is useful to improve patient compliance and to achieve predictable and optimized therapeutic plasma concentrations. Direct compression and wet granulation were initially used as methods for tablet manufacture. The direct compression method of manufacture produced tablets that exhibited formulation and manufacturing difficulties. Mini-tablets containing veraparnil hydrochloride were then prepared by wet granulation using Surelease® E-7-19010.and Eudragit® NE 30D as the granulating agents after which the granules were incorporated with an hydrophilic matrix material, Carbopol® 974P NF. Granule and powder blends were evaluated using the angle of repose, loose and tapped bulk density, Can's compressibility index, Hausner's ratio and drug content. Granules with good flow properties and satisfactory compressibility were used for further studies. Tablets were subjected to thickness, diameter and weight variation tests, crushing strength, tensile strength, friability and content uniformity studies. Tablets that showed acceptable pharmaco-technical properties were selected for further analysis. Drug content uniformity and dissolution release rates were determined using a validated isocratic HPLC method. Initially, USP apparatus 1 and 3 dissolution apparatus were used to determine in-vitro drug release rates from the formulations over a 22-hour period. USP apparatus 3 was finally selected as it offers the advantages of mimicking, in part, the changes in the physicochemical environment experienced by products in the gastro-intestinal tract. Differences in release rates between the test formulations and a commercially available product, Isoptin® SR were observed at different pH's using USP apparatus 1. The release of veraparnil hydrochloride from matrix tablets was pH dependent and was markedly reduced at higher pH values. This may be due, in part, to the poor solubility of veraparnil hydrochloride at these pH values and also the possible interaction of verapamil hydrochloride with anionic polymers used in these formulations. Swelling and erosion behaviour of the tablets were evaluated and differences in behaviour were observed which may be attributed to the physico-chemical characteristics of the polymers used in this study. In-vitro dissolution profiles were characterized by the difference (j1) and similarity factor (j2) and also by a new similarity factor, Sct. In addition, the mechanism of drug release from these dosage forms was mainly evaluated using the Korsmeyer-Peppas model and the kinetics of drug release assessed using other models, including Zero order, First order, Higuchi, HixsonCrowell, Weibull and the Baker-Lonsdale model. Dissolution kinetics were best described by application of the Weibull model, and the Korsmeyer-Peppas model. The release exponent, n, confirmed that drug release from these dosage forms was due to the mixed effects of diffusion and swelling and therefore, anomalous release kinetics are predominant. In conclusion, two test batches were found to be comparable to the reference product Isoptin® SR with respect to their in-vitro release profiles.
- Full Text:
- Authors: Khamanga, Sandile Maswazi Malungelo
- Date: 2005
- Subjects: Verapamil , Tablets (Medicine) , Drugs -- Administration , Cardiovascular agents , Calcium -- Antagonists , Drugs -- Controlled release
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3869 , http://hdl.handle.net/10962/d1018236
- Description: The oral route of drug administration is most extensively used due to the obvious ease of administration. Verapamil hydrochloride is a WHO listed phenylalkylarnine, L-type calcium channel antagonist that is mainly indicated for cardiovascular disorders such as angina pectoris, supraventricular tachycardia and hypertension. Due to its relatively short half-life of approximately 4.0 hours, the formulation of a sustained-release dosage form is useful to improve patient compliance and to achieve predictable and optimized therapeutic plasma concentrations. Direct compression and wet granulation were initially used as methods for tablet manufacture. The direct compression method of manufacture produced tablets that exhibited formulation and manufacturing difficulties. Mini-tablets containing veraparnil hydrochloride were then prepared by wet granulation using Surelease® E-7-19010.and Eudragit® NE 30D as the granulating agents after which the granules were incorporated with an hydrophilic matrix material, Carbopol® 974P NF. Granule and powder blends were evaluated using the angle of repose, loose and tapped bulk density, Can's compressibility index, Hausner's ratio and drug content. Granules with good flow properties and satisfactory compressibility were used for further studies. Tablets were subjected to thickness, diameter and weight variation tests, crushing strength, tensile strength, friability and content uniformity studies. Tablets that showed acceptable pharmaco-technical properties were selected for further analysis. Drug content uniformity and dissolution release rates were determined using a validated isocratic HPLC method. Initially, USP apparatus 1 and 3 dissolution apparatus were used to determine in-vitro drug release rates from the formulations over a 22-hour period. USP apparatus 3 was finally selected as it offers the advantages of mimicking, in part, the changes in the physicochemical environment experienced by products in the gastro-intestinal tract. Differences in release rates between the test formulations and a commercially available product, Isoptin® SR were observed at different pH's using USP apparatus 1. The release of veraparnil hydrochloride from matrix tablets was pH dependent and was markedly reduced at higher pH values. This may be due, in part, to the poor solubility of veraparnil hydrochloride at these pH values and also the possible interaction of verapamil hydrochloride with anionic polymers used in these formulations. Swelling and erosion behaviour of the tablets were evaluated and differences in behaviour were observed which may be attributed to the physico-chemical characteristics of the polymers used in this study. In-vitro dissolution profiles were characterized by the difference (j1) and similarity factor (j2) and also by a new similarity factor, Sct. In addition, the mechanism of drug release from these dosage forms was mainly evaluated using the Korsmeyer-Peppas model and the kinetics of drug release assessed using other models, including Zero order, First order, Higuchi, HixsonCrowell, Weibull and the Baker-Lonsdale model. Dissolution kinetics were best described by application of the Weibull model, and the Korsmeyer-Peppas model. The release exponent, n, confirmed that drug release from these dosage forms was due to the mixed effects of diffusion and swelling and therefore, anomalous release kinetics are predominant. In conclusion, two test batches were found to be comparable to the reference product Isoptin® SR with respect to their in-vitro release profiles.
- Full Text:
Fractured solidarities: labour regulation, workplace restructuring, and employment 'flexibility' in Namibia
- Authors: Klerck, Gilton
- Date: 2005
- Subjects: Industrial relations -- Namibia Labor -- Namibia Labor unions -- Namibia Organizational change -- Namibia Labor laws and legislation -- Namibia Casual labor -- Namibia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3343 , http://hdl.handle.net/10962/d1004898
- Description: A central concern of this thesis is the expansion, distribution and control of 'non-standard' employment in Namibia since independence. The employment relationship has assumed various historical forms under capitalism, each of which corresponds to a specific mode of regulation with distinct structural dynamics. An attempt is made to extend the regulation approach 'downwards' to account for the problem of order in the workplace and to place the employment relationship within its own regulatory framework. The point of departure in this study of the dynamics of labour regulation is the contradictory nature of labour's incorporation, allocation, control and reproduction within the labour market. The employment relationship is never only an economic exchange, but is also mediated through an institutional framework that connects the processes of production and social reproduction, and regulates conflicting interests inside and outside the workplace. This relationship, as critical realists have pointed out, is a product of the indeterminate intersection of several generative structures. The roots of these generative structures can be traced to three sets of social processes: the processes of production and the structuring of labour demand; the processes of social reproduction and the structuring of labour supply; and the forces of regulation. Non-standard employment is viewed as a particular social and spatio-temporal 'fix' for the various regulatory dilemmas generated by the standard employment relationship. This conception underscores the fact that a national system of labour regulation decisively shapes the conditions under which employers are able to casualise a part of their workforce. The differential experience across national boundaries suggests that analytical space needs to be provided for systems of labour market regulation which may either accentuate or moderate pressures for casualisation. Segmentation on the demand side of the labour market is explored through an analysis of the types of non-standard jobs created in different economic sectors. The various forms of employment 'flexibility' tend to vary in importance according to the specific manner in which a firm chooses to compete. Consequently, non-standard employees are distributed in a complex and uneven manner across industrial sectors and the occupational hierarchy, and face a diverse range of possibilities and liabilities that shape their levels and forms of participation in the labour market. By counteracting the homogenisation effects of labour law and collective bargaining, the mobilisation of cheap and disposable labour through non-standard employment contracts allows employers much greater discretion in constructing the wage-effort bargain. With non-standard employment, social and statutory regulation is weak or underdeveloped and hence managerial control is autocratic, with a significant contractual component. Although the changing social composition of the workforce associated with employment 'flexibility' poses serious challenges to the modes of organisation that have long served the labour movement, trade unions in Namibia and elsewhere have been slow to respond to the threats of casualisation. Of concern here, is the extent to which attempts to promote the security of existing union members is compatible with attempts to organise non-standard employees. This thesis shows that the unions have developed a complex amalgam of strategies in their efforts to regulate non-standard employment relationships.
- Full Text:
- Authors: Klerck, Gilton
- Date: 2005
- Subjects: Industrial relations -- Namibia Labor -- Namibia Labor unions -- Namibia Organizational change -- Namibia Labor laws and legislation -- Namibia Casual labor -- Namibia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3343 , http://hdl.handle.net/10962/d1004898
- Description: A central concern of this thesis is the expansion, distribution and control of 'non-standard' employment in Namibia since independence. The employment relationship has assumed various historical forms under capitalism, each of which corresponds to a specific mode of regulation with distinct structural dynamics. An attempt is made to extend the regulation approach 'downwards' to account for the problem of order in the workplace and to place the employment relationship within its own regulatory framework. The point of departure in this study of the dynamics of labour regulation is the contradictory nature of labour's incorporation, allocation, control and reproduction within the labour market. The employment relationship is never only an economic exchange, but is also mediated through an institutional framework that connects the processes of production and social reproduction, and regulates conflicting interests inside and outside the workplace. This relationship, as critical realists have pointed out, is a product of the indeterminate intersection of several generative structures. The roots of these generative structures can be traced to three sets of social processes: the processes of production and the structuring of labour demand; the processes of social reproduction and the structuring of labour supply; and the forces of regulation. Non-standard employment is viewed as a particular social and spatio-temporal 'fix' for the various regulatory dilemmas generated by the standard employment relationship. This conception underscores the fact that a national system of labour regulation decisively shapes the conditions under which employers are able to casualise a part of their workforce. The differential experience across national boundaries suggests that analytical space needs to be provided for systems of labour market regulation which may either accentuate or moderate pressures for casualisation. Segmentation on the demand side of the labour market is explored through an analysis of the types of non-standard jobs created in different economic sectors. The various forms of employment 'flexibility' tend to vary in importance according to the specific manner in which a firm chooses to compete. Consequently, non-standard employees are distributed in a complex and uneven manner across industrial sectors and the occupational hierarchy, and face a diverse range of possibilities and liabilities that shape their levels and forms of participation in the labour market. By counteracting the homogenisation effects of labour law and collective bargaining, the mobilisation of cheap and disposable labour through non-standard employment contracts allows employers much greater discretion in constructing the wage-effort bargain. With non-standard employment, social and statutory regulation is weak or underdeveloped and hence managerial control is autocratic, with a significant contractual component. Although the changing social composition of the workforce associated with employment 'flexibility' poses serious challenges to the modes of organisation that have long served the labour movement, trade unions in Namibia and elsewhere have been slow to respond to the threats of casualisation. Of concern here, is the extent to which attempts to promote the security of existing union members is compatible with attempts to organise non-standard employees. This thesis shows that the unions have developed a complex amalgam of strategies in their efforts to regulate non-standard employment relationships.
- Full Text:
Geology, structure and mineralization of the Onguati area, Karibib district, central Namibia
- Authors: Viljoen, Wayne
- Date: 2005
- Subjects: Geology -- Namibia -- Karibib , Geology, Structural -- Namibia -- Karibib , Mines and mineral resources -- Namibia -- Karibib
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4964 , http://hdl.handle.net/10962/d1005576 , Geology -- Namibia -- Karibib , Geology, Structural -- Namibia -- Karibib , Mines and mineral resources -- Namibia -- Karibib
- Description: The study area is situated in the Southern Central Zone of the intracontinental Pan-African Damara Orogen, approximately 20km NNE of Navachab Gold Mine in the Karibib district of Namibia. Mesothermal vein systems with Cu-Fe±Au mineralization are hosted by amphibolite facies calcitic and dolomitic marbles belonging to the Navachab Member of the Karibib Formation, and are best developed around the defunct Onguati Copper Mine, Brown Mountain and Western Workings areas. The Onguati study area is located in the saddle region of a moderately-to-gently inclined anticlinorium that experienced significant flattening during NNW-SSE-directed compression. The parallelogram arrangement of ENE- and NNE-trending thrusts and reverse faults that surround the Onguati study area may have developed when the direction of greatest principle subregional stress was oriented WSW-ESE. These structures define part of a Riedel shear system and later faults may have developed in the position of R and P shears respectively. Significant strain partitioning occurred between the ductile calcitic marbles which host the best developed, shear-related vein systems and the more competent dolomitic marbles. The thickness distributions of veins in the marbles of the Onguati Mine, Brown Mountain and Western Workings areas conform to a fractal or power-law distribution, The most intensely mineralized vein systems in the Onguati Mine and Western Workings calcitic marbles share similar low fractal dimensions (D-values) of 0.41 and 0.37 respectively. Veins In the calcitic and dolomitic marbles of the Brown Mountain area and in the dolomitic marbles of Western Workings have elevated D-values (>0.60) and are poorly mineralized. The low D-values «0.40) of the well mineralized vein systems reflect the higher degree of fracture connectivity. These vein systems were capable of efficiently draining and localizing large volumes of mineralizing fluids from crustal-scale structures. A metamorphic devolatization model is proposed where the entire Damaran metasedimentary and meta-volcanic package is seen as a large source area of very low concentrations of Cu, Au and other metals. Localization of deformation into crustal-scale faults and shear zones led to regional-scale hydrothermal fluid flow and focussing into the upstream fracture networks of the Onguati study area. Strong mineralization resulted when fluids encountered the reactive marble lithologies
- Full Text:
- Authors: Viljoen, Wayne
- Date: 2005
- Subjects: Geology -- Namibia -- Karibib , Geology, Structural -- Namibia -- Karibib , Mines and mineral resources -- Namibia -- Karibib
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4964 , http://hdl.handle.net/10962/d1005576 , Geology -- Namibia -- Karibib , Geology, Structural -- Namibia -- Karibib , Mines and mineral resources -- Namibia -- Karibib
- Description: The study area is situated in the Southern Central Zone of the intracontinental Pan-African Damara Orogen, approximately 20km NNE of Navachab Gold Mine in the Karibib district of Namibia. Mesothermal vein systems with Cu-Fe±Au mineralization are hosted by amphibolite facies calcitic and dolomitic marbles belonging to the Navachab Member of the Karibib Formation, and are best developed around the defunct Onguati Copper Mine, Brown Mountain and Western Workings areas. The Onguati study area is located in the saddle region of a moderately-to-gently inclined anticlinorium that experienced significant flattening during NNW-SSE-directed compression. The parallelogram arrangement of ENE- and NNE-trending thrusts and reverse faults that surround the Onguati study area may have developed when the direction of greatest principle subregional stress was oriented WSW-ESE. These structures define part of a Riedel shear system and later faults may have developed in the position of R and P shears respectively. Significant strain partitioning occurred between the ductile calcitic marbles which host the best developed, shear-related vein systems and the more competent dolomitic marbles. The thickness distributions of veins in the marbles of the Onguati Mine, Brown Mountain and Western Workings areas conform to a fractal or power-law distribution, The most intensely mineralized vein systems in the Onguati Mine and Western Workings calcitic marbles share similar low fractal dimensions (D-values) of 0.41 and 0.37 respectively. Veins In the calcitic and dolomitic marbles of the Brown Mountain area and in the dolomitic marbles of Western Workings have elevated D-values (>0.60) and are poorly mineralized. The low D-values «0.40) of the well mineralized vein systems reflect the higher degree of fracture connectivity. These vein systems were capable of efficiently draining and localizing large volumes of mineralizing fluids from crustal-scale structures. A metamorphic devolatization model is proposed where the entire Damaran metasedimentary and meta-volcanic package is seen as a large source area of very low concentrations of Cu, Au and other metals. Localization of deformation into crustal-scale faults and shear zones led to regional-scale hydrothermal fluid flow and focussing into the upstream fracture networks of the Onguati study area. Strong mineralization resulted when fluids encountered the reactive marble lithologies
- Full Text:
Growth, feeding and sex change in the sequential protandric shrimp Nauticaris marionis Bate 1888 at the Prince Edward Islands (Southern Ocean)
- Authors: Vumazonke, Lukhanyiso Unam
- Date: 2005
- Subjects: Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5704 , http://hdl.handle.net/10962/d1005390 , Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Description: Demographic parameters and the general biology of the subantarctic shrimp Nauticaris marionis from the Prince Edward Islands were investigated. The carapace length is the most accurate indicator of body size and it was confirmed that N. marionis is a partially protandric hermaphrodite. Gravid females of N. marionis observed mainly in March with negligible hatching persisting until April/May. The majority of juveniles develop into males. Juveniles are characterised by an appendage on the endopodite of the first pleopod called the appendix interna or a.i.1. Juveniles that develop into males do so by growing a further appendage on the endopodite of the second pleopod. This appendage characterises males and is called the appendix masculina (or a.m.). Juveniles may develop directly into primary females through the development of an ovary and the loss of the a.i.1. The sequence differs among individuals, with some developing the ovary before losing the a.i.1 and others losing the a.i.1 first. Loss of the a.i.1 appears to be by shedding during a single moult, rather than by atrophy. Females can also develop by an alternative route as secondary females. Such animals first become males with an a.m. and then develop an ovary, thus forming an intermediate form called a tertium quid, or “third thing”. Again, there are two forms of tertium quid. Tertia quae a have the a.m. as well as the a.i.1. Tertia quae b have the a.m. in combination with an ovary but no a.i.1. Either form of tertium quid can develop into a secondary female through loss of the a.m., and in the case of the tertium quid a, loss of the a.i.1. It is unclear whether sexual differentiation occurs in the plankton or just after N. marionis settles on the benthos. The results of gut content analysis suggest that N. marionis is an opportunistic feeder, preying on a variety of prey with a preference for detritus, benthic amphipods and gastropods. Cannibalism of conspecific pleopods by large individuals of N. marionis occurred mostly in females, particularly in incubation containers. Cannibalism also occurs in males, and its occurrence depends on individual size, not gender. No diel patterns were observed in the feeding activity of N. marionis. In situ daily rations of males (carapace length <7mm) and females (>7mm) were equivalent to ≈10% and ≈5% of body dry weight, respectively. The von Bertalanffy growth curve parameters were empirically identified, by cohort analysis of data collected during 4 years, as K = 0.22239/year, L[subscript]∞ = 14.05789mm, t₀ = -0.05174, L₀ = 0.16083mm. N. marionis can survive up to seven years under natural conditions.
- Full Text:
- Authors: Vumazonke, Lukhanyiso Unam
- Date: 2005
- Subjects: Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5704 , http://hdl.handle.net/10962/d1005390 , Shrimps -- Prince Edward Islands , Shrimps -- Feeding and feeds , Shrimps -- Nutrition , Shrimps -- Growth
- Description: Demographic parameters and the general biology of the subantarctic shrimp Nauticaris marionis from the Prince Edward Islands were investigated. The carapace length is the most accurate indicator of body size and it was confirmed that N. marionis is a partially protandric hermaphrodite. Gravid females of N. marionis observed mainly in March with negligible hatching persisting until April/May. The majority of juveniles develop into males. Juveniles are characterised by an appendage on the endopodite of the first pleopod called the appendix interna or a.i.1. Juveniles that develop into males do so by growing a further appendage on the endopodite of the second pleopod. This appendage characterises males and is called the appendix masculina (or a.m.). Juveniles may develop directly into primary females through the development of an ovary and the loss of the a.i.1. The sequence differs among individuals, with some developing the ovary before losing the a.i.1 and others losing the a.i.1 first. Loss of the a.i.1 appears to be by shedding during a single moult, rather than by atrophy. Females can also develop by an alternative route as secondary females. Such animals first become males with an a.m. and then develop an ovary, thus forming an intermediate form called a tertium quid, or “third thing”. Again, there are two forms of tertium quid. Tertia quae a have the a.m. as well as the a.i.1. Tertia quae b have the a.m. in combination with an ovary but no a.i.1. Either form of tertium quid can develop into a secondary female through loss of the a.m., and in the case of the tertium quid a, loss of the a.i.1. It is unclear whether sexual differentiation occurs in the plankton or just after N. marionis settles on the benthos. The results of gut content analysis suggest that N. marionis is an opportunistic feeder, preying on a variety of prey with a preference for detritus, benthic amphipods and gastropods. Cannibalism of conspecific pleopods by large individuals of N. marionis occurred mostly in females, particularly in incubation containers. Cannibalism also occurs in males, and its occurrence depends on individual size, not gender. No diel patterns were observed in the feeding activity of N. marionis. In situ daily rations of males (carapace length <7mm) and females (>7mm) were equivalent to ≈10% and ≈5% of body dry weight, respectively. The von Bertalanffy growth curve parameters were empirically identified, by cohort analysis of data collected during 4 years, as K = 0.22239/year, L[subscript]∞ = 14.05789mm, t₀ = -0.05174, L₀ = 0.16083mm. N. marionis can survive up to seven years under natural conditions.
- Full Text:
How policy discourses and contextual realities influence environmental teaching and learning processes in early childhood development: a case study of the Raglan Road child care centre
- Authors: Vallabh, Priya
- Date: 2005
- Subjects: Early childhood education -- South Africa , Health education -- South Africa , Environmental education -- Study and teaching -- South Africa , Day care centers -- South Africa , Child development
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1559 , http://hdl.handle.net/10962/d1003441 , Early childhood education -- South Africa , Health education -- South Africa , Environmental education -- Study and teaching -- South Africa , Day care centers -- South Africa , Child development
- Description: This case study considers the relationship between context, school policy and environmental teaching and learning processes at a community-based early childhood development centre in South Africa. The study recognises that educational practices in the early childhood development field are shaped by historical, cultural, economic and political realities at both local and national levels. It is from the understanding that each school is a unique composition of these shaping factors that the research was designed to consider the community-based school participating in this study. By compiling a contextual profile, this study attempts to consider dominant contextual factors affecting the school. Through the critical discourse analysis of a school policy document, this study considers local level policy, and through the literature chapter, national policy. Teacher interviews provide insight into teacher understanding of school policy in response to contextual issues, as well as providing insight into how teachers perceive their translation of policy into teaching practice. Observations of lessons in the centre provided an. opportunity to see how context and policy translated into and influenced environmental teaching and learning processes. This study looks at how environmental education is addressed in the Raglan Road Child Care Centre, and provides insight into how environmental education within the context of the school and in relation to school policy may be strengthened. It comments on the tensions and ambivalences arising from the relationships between context, policy and environmental teaching and learning processes and makes recommendations to address these ambivalences in ways that are contextually relevant. The main recommendations were designed to be practically useful for the school involved in the study and are focused around engaging the ambivalences emerging from this study to open up 'spaces' for deliberating environmental teaching and learning processes and other tensions arising out of the study at an ECD level. Recommendations included: 1) engaging with the strong development focus in school policy and the educational focus in national policy and teacher discourse; 2) deliberating the ways in which school policy and national policy respond to risk; 3) engaging with the ambivalence in the school-parent relationship; 4) the re-alignment of the explicit curriculum and broadening the contextually-based view of whole child development; and 5) engaging the ambivalence in approaches to education at the centre.
- Full Text:
- Authors: Vallabh, Priya
- Date: 2005
- Subjects: Early childhood education -- South Africa , Health education -- South Africa , Environmental education -- Study and teaching -- South Africa , Day care centers -- South Africa , Child development
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1559 , http://hdl.handle.net/10962/d1003441 , Early childhood education -- South Africa , Health education -- South Africa , Environmental education -- Study and teaching -- South Africa , Day care centers -- South Africa , Child development
- Description: This case study considers the relationship between context, school policy and environmental teaching and learning processes at a community-based early childhood development centre in South Africa. The study recognises that educational practices in the early childhood development field are shaped by historical, cultural, economic and political realities at both local and national levels. It is from the understanding that each school is a unique composition of these shaping factors that the research was designed to consider the community-based school participating in this study. By compiling a contextual profile, this study attempts to consider dominant contextual factors affecting the school. Through the critical discourse analysis of a school policy document, this study considers local level policy, and through the literature chapter, national policy. Teacher interviews provide insight into teacher understanding of school policy in response to contextual issues, as well as providing insight into how teachers perceive their translation of policy into teaching practice. Observations of lessons in the centre provided an. opportunity to see how context and policy translated into and influenced environmental teaching and learning processes. This study looks at how environmental education is addressed in the Raglan Road Child Care Centre, and provides insight into how environmental education within the context of the school and in relation to school policy may be strengthened. It comments on the tensions and ambivalences arising from the relationships between context, policy and environmental teaching and learning processes and makes recommendations to address these ambivalences in ways that are contextually relevant. The main recommendations were designed to be practically useful for the school involved in the study and are focused around engaging the ambivalences emerging from this study to open up 'spaces' for deliberating environmental teaching and learning processes and other tensions arising out of the study at an ECD level. Recommendations included: 1) engaging with the strong development focus in school policy and the educational focus in national policy and teacher discourse; 2) deliberating the ways in which school policy and national policy respond to risk; 3) engaging with the ambivalence in the school-parent relationship; 4) the re-alignment of the explicit curriculum and broadening the contextually-based view of whole child development; and 5) engaging the ambivalence in approaches to education at the centre.
- Full Text:
Identification of cis-elements and transacting factors involved in the abiotic stress responses of plants
- Authors: Maclear, Athlee
- Date: 2005 , 2013-06-10
- Subjects: Plants -- Effect of stress on , Proteins -- Analysis , Bioinformatics , DNA , Plant genetics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4074 , http://hdl.handle.net/10962/d1007236 , Plants -- Effect of stress on , Proteins -- Analysis , Bioinformatics , DNA , Plant genetics
- Description: Many stress situations limit plant growth, resulting in crop production difficulties. Population growth, limited availability and over-utilization of arable land, and intolerant crop species have resulted in tremendous strain being placed on agriculturalists to produce enough to sustain the world's population. An understanding of the principles involved in plant resistance to environmental stress will enable scientists to harness these mechanisms to create stress-tolerant crop species, thus increasing crop production, and enabling the farming of previously unproductive land. This research project uses computational and bioinformatics techniques to explore the promoter regions of genes, encoding proteins that are up- or down-regulated in response to specific abiotic stresses, with the aim of identifying common patterns in the cis-elements governing the regulation of these abiotic stress responsive genes. An initial dataset of fifty known genes encoding for proteins reported to be up- or down-regulated in response to plant stresses that result in water-deficit at the cellular level viz. drought, low temperature, and salinity, were identified, and a postgreSQL database created to store relevant information pertaining to these genes and the proteins encoded by them. The genomic DNA was obtained where possible, and the promoter and intron regions identified. The Neural Network Promoter Prediction (NNPP) software package was used to predict the transcription start signal (TSS) and the promoter searching software tool, TESS (Transcription Element Search Software) used to identify known and user-defined cis-elements within the promoter regions of these genes. Currently available promoter prediction software analysis tools are reported to predict one promoter per kilobase of DNA, whilst functional promoters are thought to only occur one in 30-40 kilobases, which indicates that a large perccntage of predictions are likely to be false positives (pedersen et. al., 1999). NNPP was chosen as it was rated as the highest performing promoter prediction software tool by Fickett and Hatzigeorgiou (1997) in a thorough review of eukaryotic promoter prediction algorithms, however results were less than promising as very few predicted TSS were identified in the area 50 bps up- and downstream of the gene start site, where biologically functional TSSs are known to occur (Reese, 2000; Fickett and Hatzigeorgiou, 1997). TESS results seemed to support the hypothesis that drought, low-temperature and high salinity plant stress response proteins have similar as-elements in their promoter regions, and suggested links to various other gene regulation mechanisms viz. gibberellin-, light-, auxin- and development-regulated gene expression, highlighting the vast complexity of plant stress response processes. Although far from conclusive, results provide a valuable basis for future comparative promoter studies that will attempt to deduce possible common transcriptional initiation of abiotic stress response genes. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Maclear, Athlee
- Date: 2005 , 2013-06-10
- Subjects: Plants -- Effect of stress on , Proteins -- Analysis , Bioinformatics , DNA , Plant genetics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4074 , http://hdl.handle.net/10962/d1007236 , Plants -- Effect of stress on , Proteins -- Analysis , Bioinformatics , DNA , Plant genetics
- Description: Many stress situations limit plant growth, resulting in crop production difficulties. Population growth, limited availability and over-utilization of arable land, and intolerant crop species have resulted in tremendous strain being placed on agriculturalists to produce enough to sustain the world's population. An understanding of the principles involved in plant resistance to environmental stress will enable scientists to harness these mechanisms to create stress-tolerant crop species, thus increasing crop production, and enabling the farming of previously unproductive land. This research project uses computational and bioinformatics techniques to explore the promoter regions of genes, encoding proteins that are up- or down-regulated in response to specific abiotic stresses, with the aim of identifying common patterns in the cis-elements governing the regulation of these abiotic stress responsive genes. An initial dataset of fifty known genes encoding for proteins reported to be up- or down-regulated in response to plant stresses that result in water-deficit at the cellular level viz. drought, low temperature, and salinity, were identified, and a postgreSQL database created to store relevant information pertaining to these genes and the proteins encoded by them. The genomic DNA was obtained where possible, and the promoter and intron regions identified. The Neural Network Promoter Prediction (NNPP) software package was used to predict the transcription start signal (TSS) and the promoter searching software tool, TESS (Transcription Element Search Software) used to identify known and user-defined cis-elements within the promoter regions of these genes. Currently available promoter prediction software analysis tools are reported to predict one promoter per kilobase of DNA, whilst functional promoters are thought to only occur one in 30-40 kilobases, which indicates that a large perccntage of predictions are likely to be false positives (pedersen et. al., 1999). NNPP was chosen as it was rated as the highest performing promoter prediction software tool by Fickett and Hatzigeorgiou (1997) in a thorough review of eukaryotic promoter prediction algorithms, however results were less than promising as very few predicted TSS were identified in the area 50 bps up- and downstream of the gene start site, where biologically functional TSSs are known to occur (Reese, 2000; Fickett and Hatzigeorgiou, 1997). TESS results seemed to support the hypothesis that drought, low-temperature and high salinity plant stress response proteins have similar as-elements in their promoter regions, and suggested links to various other gene regulation mechanisms viz. gibberellin-, light-, auxin- and development-regulated gene expression, highlighting the vast complexity of plant stress response processes. Although far from conclusive, results provide a valuable basis for future comparative promoter studies that will attempt to deduce possible common transcriptional initiation of abiotic stress response genes. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
Impacts of wildlife and cattle grazing on spider (araneae) biodiversity in a highland savanna ecosystem, in Laikipia, Central Kenya
- Authors: Warui, Charles Mwaura
- Date: 2005
- Subjects: Spiders -- Kenya Environmental monitoring -- Kenya Savanna ecology -- Kenya Biodiversity -- Kenya Species diversity -- Kenya Wildlife management -- Kenya Herbivores -- Ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5712 , http://hdl.handle.net/10962/d1005398
- Description: Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.
- Full Text:
- Authors: Warui, Charles Mwaura
- Date: 2005
- Subjects: Spiders -- Kenya Environmental monitoring -- Kenya Savanna ecology -- Kenya Biodiversity -- Kenya Species diversity -- Kenya Wildlife management -- Kenya Herbivores -- Ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5712 , http://hdl.handle.net/10962/d1005398
- Description: Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.
- Full Text:
In vitro release of ketoprofen from proprietary and extemporaneously manufactured gels
- Tettey-Amlalo, Ralph Nii Okai
- Authors: Tettey-Amlalo, Ralph Nii Okai
- Date: 2005
- Subjects: Transdermal medication , Drug delivery systems , High performance liquid chromatography , Nonsteroidal anti-inflammatory agents , Rheumatoid arthritis -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3797 , http://hdl.handle.net/10962/d1003275 , Transdermal medication , Drug delivery systems , High performance liquid chromatography , Nonsteroidal anti-inflammatory agents , Rheumatoid arthritis -- Treatment
- Description: Ketoprofen is a potent non-steroidal anti-inflammatory drug which is used for the treatment of rheumatoid arthritis. The oral administration of ketoprofen can cause gastric irritation and adverse renal effects. Transdermal delivery of the drug can bypass gastrointestinal disturbances and provide relatively consistent drug concentrations at the site of administration. The release of ketoprofen from proprietary gel products from three different countries was evaluated by comparing the in vitro release profiles. Twenty extemporaneously prepared ketoprofen gel formulations using Carbopol® polymers were manufactured. The effect of polymer, drug concentration, pH and solvent systems on the in vitro release of ketoprofen from these formulations were investigated. The gels were evaluated for drug content and pH. The release of the drug from all the formulations obeyed the Higuchi principle. Two static FDA approved diffusion cells, namely the modified Franz diffusion cell and the European Pharmacopoeia diffusion cell, were compared by measuring the in vitro release rate of ketoprofen from all the gel formulations through a synthetic silicone membrane. High-performance liquid chromatography and ultraviolet spectrophotometric analytical techniques were both used for the analysis of ketoprofen. The validated methods were employed for the determination of ketoprofen in the sample solutions taken from the receptor fluid. Two of the three proprietary products registered under the same manufacturing license exhibited similar results whereas the third product differed significantly. Among the variables investigated, the vehicle pH and solvent composition were found have the most significant effect on the in vitro release of ketoprofen from Carbopol® polymers. The different grades of Carbopol® polymers showed statistically significantly different release kinetics with respect to lag time. When evaluating the proprietary products, both the modified Franz diffusion cell and the European Pharmacopoeia diffusion cell were deemed adequate although higher profiles were generally obtained from the European Pharmacopoeia diffusion cells. Smoother diffusion profiles were obtained from samples analysed by high-performance liquid chromatography than by ultraviolet spectrophotometry in both diffusion cells. Sample solutions taken from Franz diffusion cells and analysed by ultraviolet spectrophotometry also produced smooth diffusion profiles. Erratic and higher diffusion profiles were observed with samples taken from the European Pharmacopoeia diffusion cell and analysed by ultraviolet spectrophotometry. The choice of diffusion cells and analytical procedure in product development must be weighed against the relatively poor reproducibility as observed with the European Pharmacopoeia diffusion cell.
- Full Text:
- Authors: Tettey-Amlalo, Ralph Nii Okai
- Date: 2005
- Subjects: Transdermal medication , Drug delivery systems , High performance liquid chromatography , Nonsteroidal anti-inflammatory agents , Rheumatoid arthritis -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3797 , http://hdl.handle.net/10962/d1003275 , Transdermal medication , Drug delivery systems , High performance liquid chromatography , Nonsteroidal anti-inflammatory agents , Rheumatoid arthritis -- Treatment
- Description: Ketoprofen is a potent non-steroidal anti-inflammatory drug which is used for the treatment of rheumatoid arthritis. The oral administration of ketoprofen can cause gastric irritation and adverse renal effects. Transdermal delivery of the drug can bypass gastrointestinal disturbances and provide relatively consistent drug concentrations at the site of administration. The release of ketoprofen from proprietary gel products from three different countries was evaluated by comparing the in vitro release profiles. Twenty extemporaneously prepared ketoprofen gel formulations using Carbopol® polymers were manufactured. The effect of polymer, drug concentration, pH and solvent systems on the in vitro release of ketoprofen from these formulations were investigated. The gels were evaluated for drug content and pH. The release of the drug from all the formulations obeyed the Higuchi principle. Two static FDA approved diffusion cells, namely the modified Franz diffusion cell and the European Pharmacopoeia diffusion cell, were compared by measuring the in vitro release rate of ketoprofen from all the gel formulations through a synthetic silicone membrane. High-performance liquid chromatography and ultraviolet spectrophotometric analytical techniques were both used for the analysis of ketoprofen. The validated methods were employed for the determination of ketoprofen in the sample solutions taken from the receptor fluid. Two of the three proprietary products registered under the same manufacturing license exhibited similar results whereas the third product differed significantly. Among the variables investigated, the vehicle pH and solvent composition were found have the most significant effect on the in vitro release of ketoprofen from Carbopol® polymers. The different grades of Carbopol® polymers showed statistically significantly different release kinetics with respect to lag time. When evaluating the proprietary products, both the modified Franz diffusion cell and the European Pharmacopoeia diffusion cell were deemed adequate although higher profiles were generally obtained from the European Pharmacopoeia diffusion cells. Smoother diffusion profiles were obtained from samples analysed by high-performance liquid chromatography than by ultraviolet spectrophotometry in both diffusion cells. Sample solutions taken from Franz diffusion cells and analysed by ultraviolet spectrophotometry also produced smooth diffusion profiles. Erratic and higher diffusion profiles were observed with samples taken from the European Pharmacopoeia diffusion cell and analysed by ultraviolet spectrophotometry. The choice of diffusion cells and analytical procedure in product development must be weighed against the relatively poor reproducibility as observed with the European Pharmacopoeia diffusion cell.
- Full Text:
Incorporating indigenous management in rock art sites in KwaZulu-Natal
- Authors: Ndlovu, Ndukuyakhe
- Date: 2005
- Subjects: Rock paintings -- Drakenberg Mountains , Cave paintings -- Drakensberg Mountains , San (African people) -- Art , Art, Prehistoric -- Drakensberg Mountains , Art, Prehistoric -- South Africa , Heritage tourism -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2089 , http://hdl.handle.net/10962/d1002652 , Rock paintings -- Drakenberg Mountains , Cave paintings -- Drakensberg Mountains , San (African people) -- Art , Art, Prehistoric -- Drakensberg Mountains , Art, Prehistoric -- South Africa , Heritage tourism -- South Africa
- Description: The majestic mountains of the uKhahlamba Drakensberg, formed many millennia ago were home to the Bushmen[footnote 1] or San people. They lived at these mountains for thousands of years before they were colonised by the Bantu speakers and the Europeans. Academic writings for many years have perpetuated the thinking that Bushman people were largely extinct. The dominance of this view in the academic writings was encouraged by historical evidence that Europeans and Bantu speakers hunted and killed Bushmen over the last several centuries. Researchers argue that the extermination of the Bushmen was because they were less human in the eyes of the foreigners, due to cattle raiding. There is still some element of this thinking amongst today’s academics, although research in the last decade is questioning this thinking. The question of whether descendants do exist is relevant to issues of rights of access to ancestral sacred sites, in particular rock art sites. At present, access to rock art sites is granted on qualification as an authentic fee-paying tourist (or affordability) rather than on group rights to a cultural heritage resource (cultural rights). Based on this, I argue that access to rock art sites is based on qualification rather than by right. This is largely driven by an approach that emphasises the physical conservation and financial sustainability of a site, rather than its spiritual maintenance. It has become clear that the interests in rock art by tourists and Bushman descendants are distinct from each other. Tourists have an aesthetic significance for rock art while Bushmen descendants have a spiritual significance for the paintings. Beyond any doubt, the physically based and financially driven approach has brought new challenges to today’s Bushmen descendants, whom in reaffirming their identities now have a new challenge to overcome. Not only are the rock art sites physically threatened but also they have lost much of their spiritual powers. Their fate lies in the hands of heritage officers who must determine access rights to the painted shelters. Both the National Heritage Resources Act and the KwaZulu-Natal Heritage Act acknowledge living heritage. However, the existence of this heritage is judged against the physical approach to rock art management. If the practises of descendants are perceived to be a threat to the rock art, they will not be approved. The case of the Duma is a classic example. Prior to the ritual ceremony at Game Pass Shelter, Kamberg, they were informed of the minimum standards for opening a rock art site to public and rules of how people should behave while visiting painted shelters. While it was evident that there are problems with the two approaches, the spiritual and physical approach, discussed in the thesis, it is important that solutions are identified. I do not believe that one approach on its own will be good enough, for reasons discussed in the thesis. Instead, the two approaches should be implemented together to compliment each other by identifying common grounds. I provide strategies as to how I believe that such a common ground can be reached. In addition, I provide my own analytical thinking as to how these strategies can be achieved. There is no general consensus over which term is appropriate. Both terms are considered by some academics to be derogatory or pejorative (Chennels 2003). San means vagabond and was given to the Bushmen by Khoi-Khoi people, because they considered themselves of a better social class, as they had domesticated animals and were more sedentary than Bushmen. However, according to WIMSA (Thoma 2003) the word San is derived from the Hai||om language meaning “people who gather”. It is normally written Saan but it has been accepted to write San. In 1993 the San requested to be called San when referred to as an entire group. If one refers to individual people/groups they like to be called by their language and cultural name i.e. Khwe, !Kung, !Xun, Ju|’hoansi, ‡Khomani, N|u, |’Auni, Hai||om, etc In this thesis, Bushmen is a preferred term, because it is a better-known term among the people who are central to this study. It is used without any insulting connotations attached to the term.
- Full Text:
- Authors: Ndlovu, Ndukuyakhe
- Date: 2005
- Subjects: Rock paintings -- Drakenberg Mountains , Cave paintings -- Drakensberg Mountains , San (African people) -- Art , Art, Prehistoric -- Drakensberg Mountains , Art, Prehistoric -- South Africa , Heritage tourism -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2089 , http://hdl.handle.net/10962/d1002652 , Rock paintings -- Drakenberg Mountains , Cave paintings -- Drakensberg Mountains , San (African people) -- Art , Art, Prehistoric -- Drakensberg Mountains , Art, Prehistoric -- South Africa , Heritage tourism -- South Africa
- Description: The majestic mountains of the uKhahlamba Drakensberg, formed many millennia ago were home to the Bushmen[footnote 1] or San people. They lived at these mountains for thousands of years before they were colonised by the Bantu speakers and the Europeans. Academic writings for many years have perpetuated the thinking that Bushman people were largely extinct. The dominance of this view in the academic writings was encouraged by historical evidence that Europeans and Bantu speakers hunted and killed Bushmen over the last several centuries. Researchers argue that the extermination of the Bushmen was because they were less human in the eyes of the foreigners, due to cattle raiding. There is still some element of this thinking amongst today’s academics, although research in the last decade is questioning this thinking. The question of whether descendants do exist is relevant to issues of rights of access to ancestral sacred sites, in particular rock art sites. At present, access to rock art sites is granted on qualification as an authentic fee-paying tourist (or affordability) rather than on group rights to a cultural heritage resource (cultural rights). Based on this, I argue that access to rock art sites is based on qualification rather than by right. This is largely driven by an approach that emphasises the physical conservation and financial sustainability of a site, rather than its spiritual maintenance. It has become clear that the interests in rock art by tourists and Bushman descendants are distinct from each other. Tourists have an aesthetic significance for rock art while Bushmen descendants have a spiritual significance for the paintings. Beyond any doubt, the physically based and financially driven approach has brought new challenges to today’s Bushmen descendants, whom in reaffirming their identities now have a new challenge to overcome. Not only are the rock art sites physically threatened but also they have lost much of their spiritual powers. Their fate lies in the hands of heritage officers who must determine access rights to the painted shelters. Both the National Heritage Resources Act and the KwaZulu-Natal Heritage Act acknowledge living heritage. However, the existence of this heritage is judged against the physical approach to rock art management. If the practises of descendants are perceived to be a threat to the rock art, they will not be approved. The case of the Duma is a classic example. Prior to the ritual ceremony at Game Pass Shelter, Kamberg, they were informed of the minimum standards for opening a rock art site to public and rules of how people should behave while visiting painted shelters. While it was evident that there are problems with the two approaches, the spiritual and physical approach, discussed in the thesis, it is important that solutions are identified. I do not believe that one approach on its own will be good enough, for reasons discussed in the thesis. Instead, the two approaches should be implemented together to compliment each other by identifying common grounds. I provide strategies as to how I believe that such a common ground can be reached. In addition, I provide my own analytical thinking as to how these strategies can be achieved. There is no general consensus over which term is appropriate. Both terms are considered by some academics to be derogatory or pejorative (Chennels 2003). San means vagabond and was given to the Bushmen by Khoi-Khoi people, because they considered themselves of a better social class, as they had domesticated animals and were more sedentary than Bushmen. However, according to WIMSA (Thoma 2003) the word San is derived from the Hai||om language meaning “people who gather”. It is normally written Saan but it has been accepted to write San. In 1993 the San requested to be called San when referred to as an entire group. If one refers to individual people/groups they like to be called by their language and cultural name i.e. Khwe, !Kung, !Xun, Ju|’hoansi, ‡Khomani, N|u, |’Auni, Hai||om, etc In this thesis, Bushmen is a preferred term, because it is a better-known term among the people who are central to this study. It is used without any insulting connotations attached to the term.
- Full Text:
Inspectors of education's perceptions of female principalship in the Rundu region of Namibia
- Authors: Kawana, Irene
- Date: 2005
- Subjects: Women school principals -- Namibia -- Rundu , Educational leadership -- Namibia -- Rundu , Sex discrimination in employment -- Namibia , School supervisors -- Namibia -- Attitudes
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2006 , http://hdl.handle.net/10962/d1015746
- Description: While women constitute more than 51% of the population and far outnumber men in teaching positions in Namibia, very few occupy positions of leadership. Male candidates are still favoured for top positions, thereby denying women the chance to gain entrance to these positions. One of the reasons for this imbalance seems to be that, in spite of conscious political effort and legislation, women may still be perceived as less effective leaders than men. This research focused on leadership in education, in particular school principals, and explored the perceptions of female principalship held by school inspectors. Three school inspectors from the Rundu Education Region were purposefully selected and interviewed. Inspectors were selected on the grounds of their considerable influence in the selection and appointment of school principals. The study found that these inspectors favour school principals who show commitment to their work, have good interpersonal working relationships, are caring, good listeners, visionary and produce good results. The inspectors attribute female principals’ success to their traditionally perceived characteristics, such as caring leadership and ability to develop good human relations. Instead of perceiving these qualities as professionally negative (as is sometimes argued in the literature) the inspectors see them as indisputable assets to leadership. The respondents acknowledge the cultural stereotyping that may have influenced male attitudes to women in the past, but argue that good leadership is not specific to gender, but part of the qualities a person possesses, regardless of sex. This study concludes that, contrary to what has been reported in many studies, these inspectors perceive women principals as effective – equal to their male counterparts or sometimes even more effective - because they are caring, well organized and good at communicating and establishing relations with others. Though these qualities are different from the traditional masculine qualities which include independence and emotional strength, the respondents recognize and legitimize them as preferred qualities in current effective leadership practice.
- Full Text:
- Authors: Kawana, Irene
- Date: 2005
- Subjects: Women school principals -- Namibia -- Rundu , Educational leadership -- Namibia -- Rundu , Sex discrimination in employment -- Namibia , School supervisors -- Namibia -- Attitudes
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2006 , http://hdl.handle.net/10962/d1015746
- Description: While women constitute more than 51% of the population and far outnumber men in teaching positions in Namibia, very few occupy positions of leadership. Male candidates are still favoured for top positions, thereby denying women the chance to gain entrance to these positions. One of the reasons for this imbalance seems to be that, in spite of conscious political effort and legislation, women may still be perceived as less effective leaders than men. This research focused on leadership in education, in particular school principals, and explored the perceptions of female principalship held by school inspectors. Three school inspectors from the Rundu Education Region were purposefully selected and interviewed. Inspectors were selected on the grounds of their considerable influence in the selection and appointment of school principals. The study found that these inspectors favour school principals who show commitment to their work, have good interpersonal working relationships, are caring, good listeners, visionary and produce good results. The inspectors attribute female principals’ success to their traditionally perceived characteristics, such as caring leadership and ability to develop good human relations. Instead of perceiving these qualities as professionally negative (as is sometimes argued in the literature) the inspectors see them as indisputable assets to leadership. The respondents acknowledge the cultural stereotyping that may have influenced male attitudes to women in the past, but argue that good leadership is not specific to gender, but part of the qualities a person possesses, regardless of sex. This study concludes that, contrary to what has been reported in many studies, these inspectors perceive women principals as effective – equal to their male counterparts or sometimes even more effective - because they are caring, well organized and good at communicating and establishing relations with others. Though these qualities are different from the traditional masculine qualities which include independence and emotional strength, the respondents recognize and legitimize them as preferred qualities in current effective leadership practice.
- Full Text:
Institutional change and ecosystem dynamics in the communal areas around Mt Coke State Forest, Eastern Cape, South Africa
- Authors: Cundill, Georgina
- Date: 2005
- Subjects: Biodiversity -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Natural resources -- Management -- South Africa -- Eastern Cape , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4746 , http://hdl.handle.net/10962/d1006959 , Biodiversity -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Natural resources -- Management -- South Africa -- Eastern Cape , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape
- Description: Through a combination of theoretical discussion and case study analysis from two villages in the Eastern Cape Province, South Africa, this thesis explores the relationship between institutional change and ecosystem dynamics through a multi-scale approach that combines local and scientific knowledge. Several conceptual approaches were combined in this study. These included; the Resilience perspective, the Sustainable Rural Livelihoods approach, the Millennium Assessment framework and principles, and the Environmental Entitlements approach. Various participatory research techniques were employed which combined with GIS technologies, existing data sets, and historical records. Common pool resource areas are social spaces, where local values attached to resources are institutionally mediated, politically nuanced, economically interpreted and historically situated. Political driving forces at various scales have played a disproportionate role in local level institutional functioning in the case study area. In particular, inappropriate state-lead interventions into land use planning have weakened local level institutions, and have reduced the ability of the linked social-ecological system to cope with change and uncertainty. People and ecosystems become more vulnerable when driving forces such as political upheaval, economic depression and drought over-lap. However, rural people are not mere spectators in the face of these driving forces; they respond both reactively and proactively to ensure resilience to change and uncertainty. Ecosystems at Mt Coke play a key role during times of crisis in rural livelihoods. These ecosystems have undergone various short-term cyclical changes largely in response to rainfall fluctuations, and some longer-term changes linked to political events and trends that have affected management practices and local institutions over time. Orthodox ecological interpretations of ecosystem change appear to ignore four key factors identified in this study: 1) the role of institutions in shaping access to resources, 2) the demand for resources in rural livelihoods, 3) the dynamic interaction between social and natural systems, and 4) the interaction between social and natural systems across scales of analysis. The future of common pool resource management lies in the combination of local and scientific knowledge through an adaptive management approach that encourages learning and adaptation in local level institutional structures.
- Full Text:
- Authors: Cundill, Georgina
- Date: 2005
- Subjects: Biodiversity -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Natural resources -- Management -- South Africa -- Eastern Cape , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:4746 , http://hdl.handle.net/10962/d1006959 , Biodiversity -- South Africa -- Eastern Cape , Ecosystem management -- South Africa -- Eastern Cape , Natural resources -- Management -- South Africa -- Eastern Cape , Sustainable agriculture -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape , Nature conservation -- South Africa -- Eastern Cape
- Description: Through a combination of theoretical discussion and case study analysis from two villages in the Eastern Cape Province, South Africa, this thesis explores the relationship between institutional change and ecosystem dynamics through a multi-scale approach that combines local and scientific knowledge. Several conceptual approaches were combined in this study. These included; the Resilience perspective, the Sustainable Rural Livelihoods approach, the Millennium Assessment framework and principles, and the Environmental Entitlements approach. Various participatory research techniques were employed which combined with GIS technologies, existing data sets, and historical records. Common pool resource areas are social spaces, where local values attached to resources are institutionally mediated, politically nuanced, economically interpreted and historically situated. Political driving forces at various scales have played a disproportionate role in local level institutional functioning in the case study area. In particular, inappropriate state-lead interventions into land use planning have weakened local level institutions, and have reduced the ability of the linked social-ecological system to cope with change and uncertainty. People and ecosystems become more vulnerable when driving forces such as political upheaval, economic depression and drought over-lap. However, rural people are not mere spectators in the face of these driving forces; they respond both reactively and proactively to ensure resilience to change and uncertainty. Ecosystems at Mt Coke play a key role during times of crisis in rural livelihoods. These ecosystems have undergone various short-term cyclical changes largely in response to rainfall fluctuations, and some longer-term changes linked to political events and trends that have affected management practices and local institutions over time. Orthodox ecological interpretations of ecosystem change appear to ignore four key factors identified in this study: 1) the role of institutions in shaping access to resources, 2) the demand for resources in rural livelihoods, 3) the dynamic interaction between social and natural systems, and 4) the interaction between social and natural systems across scales of analysis. The future of common pool resource management lies in the combination of local and scientific knowledge through an adaptive management approach that encourages learning and adaptation in local level institutional structures.
- Full Text:
Interest rate behaviour in a more transparent South African monetary policy environment
- Authors: Ballim, Goolam Hoosen
- Date: 2005
- Subjects: South African Reserve Bank , Monetary policy -- South Africa , Banks and banking -- South Africa , Interest rates -- South Africa , South Africa -- Economic policy , South Africa -- Economic conditions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1034 , http://hdl.handle.net/10962/d1004462 , South African Reserve Bank , Monetary policy -- South Africa , Banks and banking -- South Africa , Interest rates -- South Africa , South Africa -- Economic policy , South Africa -- Economic conditions
- Description: South Africa introduced inflation targeting as a monetary policy framework in 2000. This marked a sizable shift in monetary policy management from the previous "eclectic" approach and the explicit focus on M3 money supply before that. The study appraises the effectiveness of monetary policy under this new dispensation. However, the analysis does not centre on inflation outcomes, which can be a measure of effectiveness because they are the overriding objective of the South African Reserve Bank in effect, it is possible to have a target-friendly inflation rate for a length of time despite monetary policy that is ambiguous and encourages unpredictability in market interest rates. However, persistent policy opaqueness can, over time, damage a favourable inflation scenario. For instance, if the public is unsure about the Reserve Bank's desired inflation target, price setting in the wage and goods markets may eventually produce an inflation outcome that is higher than the Bank may have intended. Rather, this study adjudicates the effectiveness of monetary policy within the context of policy transparency, which is an intrinsic part of the inflation targeting framework. The study looks at the extent to which monetary policy transparency has enhanced both the anticipatory nature of the market's response to policy actions and the force that policy has on all interest rates in the financial system, particularly long-term rates. These concepts are important because through the transmission mechanism of monetary policy, the more deft market participants are at anticipating future Reserve Bank policy the greater the Bank's ability to steady the economy before the actual policy event. With the aid of regression models to estimate the response of market rates to policy changes, the results show that there is significant movement in market rates in anticipation of policy action, rather than on the day of the event or the day after. Indeed, the estimates for market rates movement on the day of and even the day after the policy action are generally minute. For instance, the R157 long-term government bond yield changes by a significant 41 basis points in response to a one percentage point change in the Reserve Bank's benchmark repo rate in the period between the last policy action and the day preceding the current action. In contrast, the R157 bond yield changes by an insignificant 2 basis points on the day of the current repo rate change and about 1 basis point the day after the current change. The results point to a robust relationship between policy transparency and the market's ability to foresee rate action. If this were not the case, it is likely that there would be persistent market surprise and, hence, noticeable movement in interest rates on the day of the rate action and perhaps even the day after. Another important observation is that monetary policy impacts significantly on both short- and long-term market rates. Again, certifying the robustness of monetary policy under the inflation targeting regime
- Full Text:
- Authors: Ballim, Goolam Hoosen
- Date: 2005
- Subjects: South African Reserve Bank , Monetary policy -- South Africa , Banks and banking -- South Africa , Interest rates -- South Africa , South Africa -- Economic policy , South Africa -- Economic conditions
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1034 , http://hdl.handle.net/10962/d1004462 , South African Reserve Bank , Monetary policy -- South Africa , Banks and banking -- South Africa , Interest rates -- South Africa , South Africa -- Economic policy , South Africa -- Economic conditions
- Description: South Africa introduced inflation targeting as a monetary policy framework in 2000. This marked a sizable shift in monetary policy management from the previous "eclectic" approach and the explicit focus on M3 money supply before that. The study appraises the effectiveness of monetary policy under this new dispensation. However, the analysis does not centre on inflation outcomes, which can be a measure of effectiveness because they are the overriding objective of the South African Reserve Bank in effect, it is possible to have a target-friendly inflation rate for a length of time despite monetary policy that is ambiguous and encourages unpredictability in market interest rates. However, persistent policy opaqueness can, over time, damage a favourable inflation scenario. For instance, if the public is unsure about the Reserve Bank's desired inflation target, price setting in the wage and goods markets may eventually produce an inflation outcome that is higher than the Bank may have intended. Rather, this study adjudicates the effectiveness of monetary policy within the context of policy transparency, which is an intrinsic part of the inflation targeting framework. The study looks at the extent to which monetary policy transparency has enhanced both the anticipatory nature of the market's response to policy actions and the force that policy has on all interest rates in the financial system, particularly long-term rates. These concepts are important because through the transmission mechanism of monetary policy, the more deft market participants are at anticipating future Reserve Bank policy the greater the Bank's ability to steady the economy before the actual policy event. With the aid of regression models to estimate the response of market rates to policy changes, the results show that there is significant movement in market rates in anticipation of policy action, rather than on the day of the event or the day after. Indeed, the estimates for market rates movement on the day of and even the day after the policy action are generally minute. For instance, the R157 long-term government bond yield changes by a significant 41 basis points in response to a one percentage point change in the Reserve Bank's benchmark repo rate in the period between the last policy action and the day preceding the current action. In contrast, the R157 bond yield changes by an insignificant 2 basis points on the day of the current repo rate change and about 1 basis point the day after the current change. The results point to a robust relationship between policy transparency and the market's ability to foresee rate action. If this were not the case, it is likely that there would be persistent market surprise and, hence, noticeable movement in interest rates on the day of the rate action and perhaps even the day after. Another important observation is that monetary policy impacts significantly on both short- and long-term market rates. Again, certifying the robustness of monetary policy under the inflation targeting regime
- Full Text:
International relations and change: a Kuhnian interpretation
- Authors: Schoeman, Jacobus
- Date: 2005
- Subjects: Kuhn, Thomas S Kuhn, Thomas S -- Criticism and interpretation International relations International relations -- Philosophy Knowledge, Theory of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2830 , http://hdl.handle.net/10962/d1003040
- Description: Using notions of change developed by Thomas Kuhn, the thesis argues that the rise of globalisation and the end of the Cold War presented the Westphalian or state-centric paradigm of international relations with a Kuhnian paradigm “crisis”. As a result, both the theory and the practice of international relations are in the midst of (what Kuhn calls) a “paradigm shift”. Emerging from this shift is (what is described in this work as) “Access World” and “Denial World” – a particular global configuration of the practice of international relations. Kuhn’s idea of “incommensurability” seems to typify the relationship between the two components of this bifurcated configuration of the international. Both intellectual risk-taking and political courage are required if the ontological struggle raging between “Access World” and “Denial World” is to be settled. This will pave the way for a new paradigm to emerge. Kuhn provides us with the insight that, to achieve this ontological breakthrough, a fundamental change in our vision of the discipline of International Relations, but also of the world of everyday international relations, is required. This entails recasting the study of International Relations as an emancipatory project and by recognising the centrality of human beings in the practice of international relations. Only if this is done, will we be able to arrive at a cosmopolitan political bargain that is appropriate for the 21st century.
- Full Text:
- Authors: Schoeman, Jacobus
- Date: 2005
- Subjects: Kuhn, Thomas S Kuhn, Thomas S -- Criticism and interpretation International relations International relations -- Philosophy Knowledge, Theory of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2830 , http://hdl.handle.net/10962/d1003040
- Description: Using notions of change developed by Thomas Kuhn, the thesis argues that the rise of globalisation and the end of the Cold War presented the Westphalian or state-centric paradigm of international relations with a Kuhnian paradigm “crisis”. As a result, both the theory and the practice of international relations are in the midst of (what Kuhn calls) a “paradigm shift”. Emerging from this shift is (what is described in this work as) “Access World” and “Denial World” – a particular global configuration of the practice of international relations. Kuhn’s idea of “incommensurability” seems to typify the relationship between the two components of this bifurcated configuration of the international. Both intellectual risk-taking and political courage are required if the ontological struggle raging between “Access World” and “Denial World” is to be settled. This will pave the way for a new paradigm to emerge. Kuhn provides us with the insight that, to achieve this ontological breakthrough, a fundamental change in our vision of the discipline of International Relations, but also of the world of everyday international relations, is required. This entails recasting the study of International Relations as an emancipatory project and by recognising the centrality of human beings in the practice of international relations. Only if this is done, will we be able to arrive at a cosmopolitan political bargain that is appropriate for the 21st century.
- Full Text:
Intraspecific comparison of Phanerochaete chrysosporium strains peroxidase production, pollutant degradation and mycelial differentiation
- Authors: Fraser, Sheena Janet
- Date: 2005
- Subjects: Phanerochaete Pollutants -- Biodegradation Lignin -- Biodegradation Bioremediation Peroxidase Fungi -- Differentiation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3964 , http://hdl.handle.net/10962/d1004023
- Description: The wood-degrading basidiomycete, Phanerochaete chrysosporium, has been studied as a model organism in elucidating the mechanisms and pathways enabling this white-rot fungus to degrade recalcitrant lignin. These same mechanisms are implicated in the mineralisation of environmentally persistent, toxic phenolic chemicals. For this reason, P. chrysosporium has been exploited in a number of environmentally sound technologies, including the degradation of the indigestible lignin component in agricultural waste for the generation of digestible animal feedstocks or high sugar content raw materials for ethanol production; brightening processes in the pulp and paper industry; the detoxification and decolourisation of industrial effluents; and the bioremediation of hazardous waste sites. The improvement of these technologies is dependant on ongoing research involving strain selection, strain development using genetic engineering approaches and process development. Strain improvement using non-recombinant methods is beneficial in that it does not limit the inherent robustness observed amongst natural variants. In this research, through a breeding programme, ten P.chrysosporium sibling strains were screened for variable ligninase activities and pollutant degradation capabilities in order to further describe previously identified differences between these organisms. A conventional stationary liquid culture technique was effectively miniaturised from 10 ml flask cultures to a 96-well microtitre plate format, for the assessment of multigenic traits amongst sibling strains. Using the 96-well microtitre plate method, the relationships between P. chrysosporium growth kinetics, peroxidase production, pollutant sensitivity and pollutant degradation was explored. Significant correlations were primarily associated with P. chrysosporium growth [P < 0.05]. Percentage p-cresol removal and tannic acid tolerance were both correlated with a shorter lag phase in growth [tannic acid: r = 0.7698, P < 0.05; p-cresol: r = 0.7584, P < 0.05] and lower stationary phase biomass levels [tannic acid: r = 0.8177, P < 0.05; p-cresol: r = 0.7803, P < 0.05]. A significant correlation (linear relationship) was also detected between percentage Poly-R478 decolourisation and time of onset of MnP [r = 0.9689, P < 0.001]. No correlation was observed between dye decolourisation, p-cresol degradation, lignin degradation and lignin peroxidase (LiP) or manganese peroxidase (MnP) activities [P > 0.05]. These results imply that differences in the biosynthetic pathways for biomass accumulation in sibling strains play a significant role in the intraspecific variation observed in pollutant sensitivity, pollutant degradation, and enzyme production. Categorical analysis of intraspecific differences was assessed according to four criterions. These included growth, extracellular peroxidase activities, tolerance to toxic pollutants and the biodegradation of model pollutants. Sibling strains showing the most variable responses in three or more of the selective criterion were recommended for further studies. These strains include P. chrysosporium ME446, BS 2.52, BS 13, BS 17, BS 18, and BS 24. Interestingly, BS 2.52 (a dikaryotic strain generating from the crossing of two haploid progeny) showed significantly lower degradation capabilities than the wildtype parent strain ME446. The inherited variability observed between sibling strains is to be further explored through proteome and transcriptome analysis and genetic linkage studies aimed at describing the mechanisms or pathways conferring tolerance to or degradation of environmental pollutants. In examining fewer organisms at this next level, the number of replicates examined can be increased and thus the power of detection of experimental procedures improved, enabling the detection of multigenic traits amongst genetically related organisms. Growth was shown to play a significant role in the intraspecific differences detected in pollutant sensitivity and degradation between sibling strains. Little is known about the mechanism of growth and differentiation, or the role of differentiation in regulating the lignolytic activity in this organism. The membrane gradostat bioreactor and a unique plug-flow membrane bioreactor were evaluated as novel tools with which to further explore the relationship between secondary metabolism, pollutant degradation and biofilm development in sibling strains. High yield MnP production at levels as high as 1478.8 U.l-1 was achieved using a laboratory scale membrane gradostat bioreactor. Furthermore, extensive mycelial differentiation and tissue formation are reported for P. chrysosporium in both the membrane gradostat bioreactor and plug-flow membrane bioreactor. Intraspecific differences in the extent of this differentiation were observed in strains ME446, BS 13, BS 17 and BS 26 cultured using the membrane gradostat bioreactor, highlighting the potential of these techniques as a platform for future strain improvement strategies.
- Full Text:
- Authors: Fraser, Sheena Janet
- Date: 2005
- Subjects: Phanerochaete Pollutants -- Biodegradation Lignin -- Biodegradation Bioremediation Peroxidase Fungi -- Differentiation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3964 , http://hdl.handle.net/10962/d1004023
- Description: The wood-degrading basidiomycete, Phanerochaete chrysosporium, has been studied as a model organism in elucidating the mechanisms and pathways enabling this white-rot fungus to degrade recalcitrant lignin. These same mechanisms are implicated in the mineralisation of environmentally persistent, toxic phenolic chemicals. For this reason, P. chrysosporium has been exploited in a number of environmentally sound technologies, including the degradation of the indigestible lignin component in agricultural waste for the generation of digestible animal feedstocks or high sugar content raw materials for ethanol production; brightening processes in the pulp and paper industry; the detoxification and decolourisation of industrial effluents; and the bioremediation of hazardous waste sites. The improvement of these technologies is dependant on ongoing research involving strain selection, strain development using genetic engineering approaches and process development. Strain improvement using non-recombinant methods is beneficial in that it does not limit the inherent robustness observed amongst natural variants. In this research, through a breeding programme, ten P.chrysosporium sibling strains were screened for variable ligninase activities and pollutant degradation capabilities in order to further describe previously identified differences between these organisms. A conventional stationary liquid culture technique was effectively miniaturised from 10 ml flask cultures to a 96-well microtitre plate format, for the assessment of multigenic traits amongst sibling strains. Using the 96-well microtitre plate method, the relationships between P. chrysosporium growth kinetics, peroxidase production, pollutant sensitivity and pollutant degradation was explored. Significant correlations were primarily associated with P. chrysosporium growth [P < 0.05]. Percentage p-cresol removal and tannic acid tolerance were both correlated with a shorter lag phase in growth [tannic acid: r = 0.7698, P < 0.05; p-cresol: r = 0.7584, P < 0.05] and lower stationary phase biomass levels [tannic acid: r = 0.8177, P < 0.05; p-cresol: r = 0.7803, P < 0.05]. A significant correlation (linear relationship) was also detected between percentage Poly-R478 decolourisation and time of onset of MnP [r = 0.9689, P < 0.001]. No correlation was observed between dye decolourisation, p-cresol degradation, lignin degradation and lignin peroxidase (LiP) or manganese peroxidase (MnP) activities [P > 0.05]. These results imply that differences in the biosynthetic pathways for biomass accumulation in sibling strains play a significant role in the intraspecific variation observed in pollutant sensitivity, pollutant degradation, and enzyme production. Categorical analysis of intraspecific differences was assessed according to four criterions. These included growth, extracellular peroxidase activities, tolerance to toxic pollutants and the biodegradation of model pollutants. Sibling strains showing the most variable responses in three or more of the selective criterion were recommended for further studies. These strains include P. chrysosporium ME446, BS 2.52, BS 13, BS 17, BS 18, and BS 24. Interestingly, BS 2.52 (a dikaryotic strain generating from the crossing of two haploid progeny) showed significantly lower degradation capabilities than the wildtype parent strain ME446. The inherited variability observed between sibling strains is to be further explored through proteome and transcriptome analysis and genetic linkage studies aimed at describing the mechanisms or pathways conferring tolerance to or degradation of environmental pollutants. In examining fewer organisms at this next level, the number of replicates examined can be increased and thus the power of detection of experimental procedures improved, enabling the detection of multigenic traits amongst genetically related organisms. Growth was shown to play a significant role in the intraspecific differences detected in pollutant sensitivity and degradation between sibling strains. Little is known about the mechanism of growth and differentiation, or the role of differentiation in regulating the lignolytic activity in this organism. The membrane gradostat bioreactor and a unique plug-flow membrane bioreactor were evaluated as novel tools with which to further explore the relationship between secondary metabolism, pollutant degradation and biofilm development in sibling strains. High yield MnP production at levels as high as 1478.8 U.l-1 was achieved using a laboratory scale membrane gradostat bioreactor. Furthermore, extensive mycelial differentiation and tissue formation are reported for P. chrysosporium in both the membrane gradostat bioreactor and plug-flow membrane bioreactor. Intraspecific differences in the extent of this differentiation were observed in strains ME446, BS 13, BS 17 and BS 26 cultured using the membrane gradostat bioreactor, highlighting the potential of these techniques as a platform for future strain improvement strategies.
- Full Text:
Investigating call control using MGCP in conjuction with SIP and H.323
- Authors: Jacobs, Ashley
- Date: 2005 , 2005-03-14
- Subjects: Communication -- Technological innovations , Digital telephone systems , Computer networks , Computer network protocols , Internet telephony
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4631 , http://hdl.handle.net/10962/d1006516 , Communication -- Technological innovations , Digital telephone systems , Computer networks , Computer network protocols , Internet telephony
- Description: Telephony used to mean using a telephone to call another telephone on the Public Switched Telephone Network (PSTN), and data networks were used purely to allow computers to communicate. However, with the advent of the Internet, telephony services have been extended to run on data networks. Telephone calls within the IP network are known as Voice over IP. These calls are carried by a number of protocols, with the most popular ones currently being Session Initiation Protocol (SIP) and H.323. Calls can be made from the IP network to the PSTN and vice versa through the use of a gateway. The gateway translates the packets from the IP network to circuits on the PSTN and vice versa to facilitate calls between the two networks. Gateways have evolved and are now split into two entities using the master/slave architecture. The master is an intelligent Media Gateway Controller (MGC) that handles the call control and signalling. The slave is a "dumb" Media Gateway (MG) that handles the translation of the media. The current gateway control protocols in use are Megaco/H.248, MGCP and Skinny. These protocols have proved themselves on the edge of the network. Furthermore, since they communicate with the call signalling VoIP protocols as well as the PSTN, they have to be the lingua franca between the two networks. Within the VoIP network, the numbers of call signalling protocols make it difficult to communicate with each other and to create services. This research investigates the use of Gateway Control Protocols as the lowest common denominator between the call signalling protocols SIP and H.323. More specifically, it uses MGCP to investigate service creation. It also considers the use of MGCP as a protocol translator between SIP and H.323. A service was created using MGCP to allow H.323 endpoints to send Short Message Service (SMS) messages. This service was then extended with minimal effort to SIP endpoints. This service investigated MGCP’s ability to handle call control from the H.323 and SIP endpoints. An MGC was then successfully used to perform as a protocol translator between SIP and H.323.
- Full Text:
- Authors: Jacobs, Ashley
- Date: 2005 , 2005-03-14
- Subjects: Communication -- Technological innovations , Digital telephone systems , Computer networks , Computer network protocols , Internet telephony
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4631 , http://hdl.handle.net/10962/d1006516 , Communication -- Technological innovations , Digital telephone systems , Computer networks , Computer network protocols , Internet telephony
- Description: Telephony used to mean using a telephone to call another telephone on the Public Switched Telephone Network (PSTN), and data networks were used purely to allow computers to communicate. However, with the advent of the Internet, telephony services have been extended to run on data networks. Telephone calls within the IP network are known as Voice over IP. These calls are carried by a number of protocols, with the most popular ones currently being Session Initiation Protocol (SIP) and H.323. Calls can be made from the IP network to the PSTN and vice versa through the use of a gateway. The gateway translates the packets from the IP network to circuits on the PSTN and vice versa to facilitate calls between the two networks. Gateways have evolved and are now split into two entities using the master/slave architecture. The master is an intelligent Media Gateway Controller (MGC) that handles the call control and signalling. The slave is a "dumb" Media Gateway (MG) that handles the translation of the media. The current gateway control protocols in use are Megaco/H.248, MGCP and Skinny. These protocols have proved themselves on the edge of the network. Furthermore, since they communicate with the call signalling VoIP protocols as well as the PSTN, they have to be the lingua franca between the two networks. Within the VoIP network, the numbers of call signalling protocols make it difficult to communicate with each other and to create services. This research investigates the use of Gateway Control Protocols as the lowest common denominator between the call signalling protocols SIP and H.323. More specifically, it uses MGCP to investigate service creation. It also considers the use of MGCP as a protocol translator between SIP and H.323. A service was created using MGCP to allow H.323 endpoints to send Short Message Service (SMS) messages. This service was then extended with minimal effort to SIP endpoints. This service investigated MGCP’s ability to handle call control from the H.323 and SIP endpoints. An MGC was then successfully used to perform as a protocol translator between SIP and H.323.
- Full Text:
Investigation into the biological removal of sulphate from ethanol distillery wastewater using sulphate-reducing prokaryotes
- Authors: Smuts, Lizl
- Date: 2005
- Subjects: Sewage -- Purification -- Biological treatment , Prokaryotes , Sulfates , Distilleries -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3941 , http://hdl.handle.net/10962/d1004000 , Sewage -- Purification -- Biological treatment , Prokaryotes , Sulfates , Distilleries -- Waste disposal
- Description: Ethanol production wastewater is known to be toxic, and is not easily biodegradable. It also consists of a variety of coloured components adding to the complex composition of this wastewater. Disposal of this wastewater into water courses is not recommended and yet is performed all over the world. Investigation of this wastewater found that there was a high concentration of sulphate which, in the presence of sulphate-reducing prokaryotes can cause sulphide corrosion of cement. The concentration of sulphate in the wastewater was approximately 2770 mg/L. It was also found that the wastewater pH was very low and discharge of the wastewater into the wastewater treatment works caused a negative impact on the overall quality of the final wastewater discharged to sea. It was found using FISH techniques that there were no sulphate-reducing prokaryotes present in the wastewaters but that a sulphate-reducing population existed on the sewer wall. An anaerobic contact process was designed to treat this wastewater targeting sulphate reduction to sulphide, to be converted into elemental sulphur and to increase the wastewater pH. The process did not achieve this aim and only approximately 20-30 % reduction in sulphate from the wastewater was achieved with little to no change in the pH. A 95 % reduction in sulphate concentration was needed in order to reach acceptable discharge limits. Sulphate reduction could not be carried out, even under ideal laboratory conditions. It was found that the barrier causing the digester failure was the high concentration of phenols present in the wastewater (3.3 g/L) together with the production of high concentrations of volatile fatty acids (on average 13 g acetic/L). These two components are known to cause digester failure, especially phenols, and phenols are usually only degraded by fungal species. It was concluded that the wastewater itself was not amenable to this method of biological treatment.
- Full Text:
- Authors: Smuts, Lizl
- Date: 2005
- Subjects: Sewage -- Purification -- Biological treatment , Prokaryotes , Sulfates , Distilleries -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3941 , http://hdl.handle.net/10962/d1004000 , Sewage -- Purification -- Biological treatment , Prokaryotes , Sulfates , Distilleries -- Waste disposal
- Description: Ethanol production wastewater is known to be toxic, and is not easily biodegradable. It also consists of a variety of coloured components adding to the complex composition of this wastewater. Disposal of this wastewater into water courses is not recommended and yet is performed all over the world. Investigation of this wastewater found that there was a high concentration of sulphate which, in the presence of sulphate-reducing prokaryotes can cause sulphide corrosion of cement. The concentration of sulphate in the wastewater was approximately 2770 mg/L. It was also found that the wastewater pH was very low and discharge of the wastewater into the wastewater treatment works caused a negative impact on the overall quality of the final wastewater discharged to sea. It was found using FISH techniques that there were no sulphate-reducing prokaryotes present in the wastewaters but that a sulphate-reducing population existed on the sewer wall. An anaerobic contact process was designed to treat this wastewater targeting sulphate reduction to sulphide, to be converted into elemental sulphur and to increase the wastewater pH. The process did not achieve this aim and only approximately 20-30 % reduction in sulphate from the wastewater was achieved with little to no change in the pH. A 95 % reduction in sulphate concentration was needed in order to reach acceptable discharge limits. Sulphate reduction could not be carried out, even under ideal laboratory conditions. It was found that the barrier causing the digester failure was the high concentration of phenols present in the wastewater (3.3 g/L) together with the production of high concentrations of volatile fatty acids (on average 13 g acetic/L). These two components are known to cause digester failure, especially phenols, and phenols are usually only degraded by fungal species. It was concluded that the wastewater itself was not amenable to this method of biological treatment.
- Full Text:
Isolation and characterization of a novel thermostable and catalytically efficient laccase from Peniophora sp. strain UD4
- Authors: Jordaan, Justin
- Date: 2005
- Subjects: Enzymes Enzymes -- Industrial applications Peniophora Laccase
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3970 , http://hdl.handle.net/10962/d1004029
- Description: Enzymes are becoming an effective tool in industrial processes, from crude applications such as bioremediation to fine processes such as chirally selective biocatalysis. The ligninolytic enzymes have recently received considerable attention for industrial application due to both their broad substrate range and their ability to degrade the most recalcitrant natural polymer, lignin. This group of enzymes was therefore identified as the target group for this study. Improved enzyme properties are constantly being sought to enhance the range of applications for enzymes. Biodiversity provides a wide variety of enzymes. Several researchers have concentrated on extremophiles as their primary source of superior enzymes, consequently neglecting temperate environments in their search for these enzymes. The relatively neglected fungal biodiversity of South Africa provided an opportunity to test the hypothesis that potentially important industrial enzymes with unusual properties could be isolated from mesophilic basidiomycetous fungi. Subsequent screening of Eastern Cape biodiversity for thermostable ligninolytic enzymes from basidiomycetes resulted in the isolation of a novel laccase enzyme from a basidiomycetous species. This fungus was identified as Peniophora sp. UD4 by phylogenetic analysis of rDNA ITS sequences. Initial studies indicated a superior optimum temperature of 70°C and thermostability, indicated by no loss in activity at 60°C over nine hours. Further characterization of the laccase revealed a broader than usual substrate range through its unusual ability to oxidatively couple DMAB and MBTH. The laccase also exhibited a broad pH oxidation range for ABTS (pH 2 – 6.8), and a relatively high affinity (K_m_ = 0.0123 mM) and catalytic efficiency (63 252 mM^(-1)^s^(-1)^) for ABTS as a substrate. The laccase activity from Peniophora sp. UD4 was shown to be comprised of three isozymes with a molecular weight of 62 kDa and pI’s of 6.33, 6.45 and 6.50. Investigation of the nutrient and physical factors affecting ligninolytic enzyme production and growth of Peniophora sp. UD4 indicated that the wild-type organism was unsuitable for large scale production of the thermostable laccase due to the low levels of laccase production. The thermostable laccase was applied to defouling of ultrafiltration membranes, bioremediation of industrial waste streams, biocatalysis, and biosensor technology as potential applications. Application of the Peniophora sp. UD4 laccase to defouling of membranes used for ultrafiltration of brown water showed large flux recoveries of 31, 21 and 21% after the first three defouling recycles respectively, compared to 3% for the control without immobilized enzyme. The novel laccase showed potential for the bioremediation of industrial waste streams, the most successful being that of bleach plant effluent, where a reduction of 66% of the phenolic load was achieved. Application of the novel laccase to biocatalytic oxidation of ferulic acid and (±)-α-pinene showed higher product yield as compared to oxidation of these compounds by Trametes versicolor laccase in mediated and non-mediated systems. The major products of (±)-α-pinene oxidation were identified as verbenol and trans-sorberol. The Peniophora sp. UD4 laccase was successfully applied to biosensor technology, which benchmarked significantly better than Trametes versicolor laccase for the detection of 4-chlorophenol. The biosensor developed with laccase from UD4 by covalent binding to a glassy carbon electrode exhibited the best combination of sensitivity and stability. This thesis shows that a laccase with superior properties was obtained from a mesophilic South African basidiomycete. The catalytic properties displayed by the novel laccase from Peniophora sp. UD4 all contribute to the increased industrial applicability of laccases, and may be the most industrially feasible enzyme of its class isolated to date.
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- Authors: Jordaan, Justin
- Date: 2005
- Subjects: Enzymes Enzymes -- Industrial applications Peniophora Laccase
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3970 , http://hdl.handle.net/10962/d1004029
- Description: Enzymes are becoming an effective tool in industrial processes, from crude applications such as bioremediation to fine processes such as chirally selective biocatalysis. The ligninolytic enzymes have recently received considerable attention for industrial application due to both their broad substrate range and their ability to degrade the most recalcitrant natural polymer, lignin. This group of enzymes was therefore identified as the target group for this study. Improved enzyme properties are constantly being sought to enhance the range of applications for enzymes. Biodiversity provides a wide variety of enzymes. Several researchers have concentrated on extremophiles as their primary source of superior enzymes, consequently neglecting temperate environments in their search for these enzymes. The relatively neglected fungal biodiversity of South Africa provided an opportunity to test the hypothesis that potentially important industrial enzymes with unusual properties could be isolated from mesophilic basidiomycetous fungi. Subsequent screening of Eastern Cape biodiversity for thermostable ligninolytic enzymes from basidiomycetes resulted in the isolation of a novel laccase enzyme from a basidiomycetous species. This fungus was identified as Peniophora sp. UD4 by phylogenetic analysis of rDNA ITS sequences. Initial studies indicated a superior optimum temperature of 70°C and thermostability, indicated by no loss in activity at 60°C over nine hours. Further characterization of the laccase revealed a broader than usual substrate range through its unusual ability to oxidatively couple DMAB and MBTH. The laccase also exhibited a broad pH oxidation range for ABTS (pH 2 – 6.8), and a relatively high affinity (K_m_ = 0.0123 mM) and catalytic efficiency (63 252 mM^(-1)^s^(-1)^) for ABTS as a substrate. The laccase activity from Peniophora sp. UD4 was shown to be comprised of three isozymes with a molecular weight of 62 kDa and pI’s of 6.33, 6.45 and 6.50. Investigation of the nutrient and physical factors affecting ligninolytic enzyme production and growth of Peniophora sp. UD4 indicated that the wild-type organism was unsuitable for large scale production of the thermostable laccase due to the low levels of laccase production. The thermostable laccase was applied to defouling of ultrafiltration membranes, bioremediation of industrial waste streams, biocatalysis, and biosensor technology as potential applications. Application of the Peniophora sp. UD4 laccase to defouling of membranes used for ultrafiltration of brown water showed large flux recoveries of 31, 21 and 21% after the first three defouling recycles respectively, compared to 3% for the control without immobilized enzyme. The novel laccase showed potential for the bioremediation of industrial waste streams, the most successful being that of bleach plant effluent, where a reduction of 66% of the phenolic load was achieved. Application of the novel laccase to biocatalytic oxidation of ferulic acid and (±)-α-pinene showed higher product yield as compared to oxidation of these compounds by Trametes versicolor laccase in mediated and non-mediated systems. The major products of (±)-α-pinene oxidation were identified as verbenol and trans-sorberol. The Peniophora sp. UD4 laccase was successfully applied to biosensor technology, which benchmarked significantly better than Trametes versicolor laccase for the detection of 4-chlorophenol. The biosensor developed with laccase from UD4 by covalent binding to a glassy carbon electrode exhibited the best combination of sensitivity and stability. This thesis shows that a laccase with superior properties was obtained from a mesophilic South African basidiomycete. The catalytic properties displayed by the novel laccase from Peniophora sp. UD4 all contribute to the increased industrial applicability of laccases, and may be the most industrially feasible enzyme of its class isolated to date.
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Isolation, purification and characterization of inulin and fructooligosaccharides from chicorium intybus and inulinase from aspergillus niger
- Mavumengwana, Vuyo Bhongelethu
- Authors: Mavumengwana, Vuyo Bhongelethu
- Date: 2005
- Subjects: Aspergillus , Inulin , Chicory -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3954 , http://hdl.handle.net/10962/d1004013 , Aspergillus , Inulin , Chicory -- South Africa
- Description: Inulin is a non-digestible carbohydrate fructan polymer consisting mainly of β (1→2) fructosyl fructose links. Enzymatic hydrolysis of inulin by inulinase results in the production of low D.P (degree of polymerization) oligosaccharides also called fructooligosaccharides(FOS). Isolation of inulin from chicory root (Chicorium intybus) was achieved by first, extraction using deionized water (600C), followed by carbonation (0.1 M Ca(OH)2 and CO2 gas). This was filtered in order to remove the non sugars, thereafter, treated successfully with polyamide 6 powder. A cation exchanger and an anion exchanger were used to further exclude other components such as tannins and pigments. The extracted inulin was quantified using the Somogyi-Nelson colourimetric assay. Chicory root (207 g, 30 % being water) yielded 30 g of the raw extract. A 100 mg of the raw extract was assayed and found to contain 11 % yield of inulin which was 80.2 % in purity and 4 % free fructose. Analysis of the crude and purified inulin extracts on the MALDI TOF spectrometry showed the samples to have a DP of 2 to 22 and 2 to 27 respectively. Maximum inulinase production from Aspergillus niger grown on inulin was observed after 60 hours. The enzyme activity was found to be 1.168 U/ml with a temperature and pH optimum of 30 °C and 7.7 respectively. The enzyme proved to be unstable as it progressively lost its total activity during attempts at purification.
- Full Text:
- Authors: Mavumengwana, Vuyo Bhongelethu
- Date: 2005
- Subjects: Aspergillus , Inulin , Chicory -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3954 , http://hdl.handle.net/10962/d1004013 , Aspergillus , Inulin , Chicory -- South Africa
- Description: Inulin is a non-digestible carbohydrate fructan polymer consisting mainly of β (1→2) fructosyl fructose links. Enzymatic hydrolysis of inulin by inulinase results in the production of low D.P (degree of polymerization) oligosaccharides also called fructooligosaccharides(FOS). Isolation of inulin from chicory root (Chicorium intybus) was achieved by first, extraction using deionized water (600C), followed by carbonation (0.1 M Ca(OH)2 and CO2 gas). This was filtered in order to remove the non sugars, thereafter, treated successfully with polyamide 6 powder. A cation exchanger and an anion exchanger were used to further exclude other components such as tannins and pigments. The extracted inulin was quantified using the Somogyi-Nelson colourimetric assay. Chicory root (207 g, 30 % being water) yielded 30 g of the raw extract. A 100 mg of the raw extract was assayed and found to contain 11 % yield of inulin which was 80.2 % in purity and 4 % free fructose. Analysis of the crude and purified inulin extracts on the MALDI TOF spectrometry showed the samples to have a DP of 2 to 22 and 2 to 27 respectively. Maximum inulinase production from Aspergillus niger grown on inulin was observed after 60 hours. The enzyme activity was found to be 1.168 U/ml with a temperature and pH optimum of 30 °C and 7.7 respectively. The enzyme proved to be unstable as it progressively lost its total activity during attempts at purification.
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Ligand isotope vibrational spectroscopic and DFT studies of Pt(II) and Cu(I) complexes
- Authors: Medina, Gerardo Juan
- Date: 2005
- Subjects: Ligands Spectrum analysis Vibrational spectra Infrared spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4324 , http://hdl.handle.net/10962/d1004982
- Description: Ligand-isotope labelling studies were performed on Zeise’s salt derivatives with pyridine N-oxide and quinoline N-oxide, their perdeuterated and O-18 isotopomers, C₂D₄ and ¹³CO, and the results of the vibrational analyses are reported. The isotopomers are modelled utilizing DFT calculations at the B3LYP level with the 6-31 G** basis set, and a pseudopotential level for the Pt atom. The calculated and observed structure and vibrational spectra correlate well. The crystal structures of [Pt(C₂2H₄)(pyO)Cl₂] and [Pt(CO)(quinO)Br₂] are reported. The frequency for the νPt-O vibration, ambiguously assigned in the literature, is here assigned unequivocally at 400 cm⁻¹. Previously observed, but inadequately described phenomena are addressed: the νN-O vibration in substituted quinoline N-oxides has been assigned previously at significantly different frequencies, depending on the nature of the substituent. This suggests that there is no specific mid-ir band associated with a high N-O character. A suitable explanation is presented for this phenomenon, showing that in low symmetry systems (eg. quinO) the N-O stretch is dispersed among several modes, whereas in high symmetry systems (eg. pyO) only a few limited modes have a high N-O character. A theoretical study of Cu(I) carbonyl compounds with macrocyclic ligands is presented. Local and global HSAB parameters applied to the donor and Cu atoms are used to explain the observed reactivities and the available spectroscopic data. Extended to [Cu(CO){H₂N(CH₂)[subscript n]NH(CH₂)[subscript m] NH₂}] BPh₄ (where n = 2, m = 2, 3 and n =3, m = 3, 4) and their -d₅ and ¹³CO isotopomers, subtle differences obtained experimentally for the CO stretching frequency in this series have been reproduced in the DFT calculations at the B3LYP level, using the 6-31 G* and 6-31 G** basis sets. Several properties (ligand pK[subscript a] values, νCO frequencies, etc.) correlate with some HSAB descriptors. Vibrational analyses are presented of Cu(I) carbonyl Schiff-base derivatives of N-Benzylidene-N’-[2-(benzyilidene-amino)-ethyl]-ethane-1,2-diamine, {2,2N3(C₆H₄R)₂}, and their -d₅ and ¹³CO isotopomers. The crystal structure of [Cu(CO){2,2N3(C₆H₅)₂}]BPh₄ is reported. From geometry optimizations and the HSAB descriptors, spectroscopic trends ([n]Cu-N and [nu]CO) are related to calculated global hardness and the Hammett substituent parameters, and are discussed in terms of σ-donation and π-backbonding of Cu- CO.
- Full Text:
- Authors: Medina, Gerardo Juan
- Date: 2005
- Subjects: Ligands Spectrum analysis Vibrational spectra Infrared spectroscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4324 , http://hdl.handle.net/10962/d1004982
- Description: Ligand-isotope labelling studies were performed on Zeise’s salt derivatives with pyridine N-oxide and quinoline N-oxide, their perdeuterated and O-18 isotopomers, C₂D₄ and ¹³CO, and the results of the vibrational analyses are reported. The isotopomers are modelled utilizing DFT calculations at the B3LYP level with the 6-31 G** basis set, and a pseudopotential level for the Pt atom. The calculated and observed structure and vibrational spectra correlate well. The crystal structures of [Pt(C₂2H₄)(pyO)Cl₂] and [Pt(CO)(quinO)Br₂] are reported. The frequency for the νPt-O vibration, ambiguously assigned in the literature, is here assigned unequivocally at 400 cm⁻¹. Previously observed, but inadequately described phenomena are addressed: the νN-O vibration in substituted quinoline N-oxides has been assigned previously at significantly different frequencies, depending on the nature of the substituent. This suggests that there is no specific mid-ir band associated with a high N-O character. A suitable explanation is presented for this phenomenon, showing that in low symmetry systems (eg. quinO) the N-O stretch is dispersed among several modes, whereas in high symmetry systems (eg. pyO) only a few limited modes have a high N-O character. A theoretical study of Cu(I) carbonyl compounds with macrocyclic ligands is presented. Local and global HSAB parameters applied to the donor and Cu atoms are used to explain the observed reactivities and the available spectroscopic data. Extended to [Cu(CO){H₂N(CH₂)[subscript n]NH(CH₂)[subscript m] NH₂}] BPh₄ (where n = 2, m = 2, 3 and n =3, m = 3, 4) and their -d₅ and ¹³CO isotopomers, subtle differences obtained experimentally for the CO stretching frequency in this series have been reproduced in the DFT calculations at the B3LYP level, using the 6-31 G* and 6-31 G** basis sets. Several properties (ligand pK[subscript a] values, νCO frequencies, etc.) correlate with some HSAB descriptors. Vibrational analyses are presented of Cu(I) carbonyl Schiff-base derivatives of N-Benzylidene-N’-[2-(benzyilidene-amino)-ethyl]-ethane-1,2-diamine, {2,2N3(C₆H₄R)₂}, and their -d₅ and ¹³CO isotopomers. The crystal structure of [Cu(CO){2,2N3(C₆H₅)₂}]BPh₄ is reported. From geometry optimizations and the HSAB descriptors, spectroscopic trends ([n]Cu-N and [nu]CO) are related to calculated global hardness and the Hammett substituent parameters, and are discussed in terms of σ-donation and π-backbonding of Cu- CO.
- Full Text: