Challenges facing school management teams in the general education and training band schools untitles
- Authors: Mapisa, Bafundi Zealous
- Date: 2011
- Subjects: School management -- Education and training
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18423 , http://hdl.handle.net/11260/d1006923
- Description: During the apartheid era, that is, before 1994, principals tended to regard schools as their properties. Principals were expected to manage schools on their own without consulting the rest of the staff. From 1994 with the advent of a new political era, South Africa ended up having one National Education System. That system came up with many changes. In the new education system, the management of the school was taken from being the principal‟s duty only, to the responsibility of a management team which is referred to as the school management team (SMT). Because of the democratic nature of the SMT, it is required that educators work co-operatively as a team. The researcher has observed that this has been a challenge in some schools where principals resisted change. On the other hand, principals of schools are facing challenges due to a lack of cooperation amongst their subordinates. The establishment of SMTs does not nullify the authority of the school principal but the challenge that lies therein is that each member of the SMT must play his or her role properly. The purpose of this study was to explore the challenges facing SMT members in the GET band schools of Circuit 2 in Centane. A qualitative investigation was undertaken with the purpose in mind to develop a better understanding of the challenges facing SMTs in Circuit 2. This study was undertaken among 5 schools in Circuit 2 in Centane which falls under Butterworth District. The researcher used convenience sampling in selecting the SMTs of schools that would participate in this research study. Due to the fact that the researcher is a principal in one of the schools in Circuit 2 he could obtain easy access to SMTs of other schools in the Circuit. The following stakeholders were identified and participated in the selected schools: principal, deputy principal and Head of Department. Qualitative data were collected through semi- structured interviews. The study was framed within the interpretive approach, and sought to unpack the perceptions of SMT members with regard to team-management . An interpretive paradigm made it possible for the researcher to gain an in-depth understanding of SMT members‟ perceptions of team-management within their contexts. The outcomes pointed to several challenges ranging from the SMT terms of reference, cooperation, sources of support and stress as a result of the work overload involved. Based on the findings, SMTs have brought the phenomenon of cooperation to the fore, and cooperation may be perceived to have many advantages. However, in order for the SMTs to play a meaningful role in curriculum management and governance issues, there is a need for them to be conversant with issues and kept abreast of developments in education as a system. It is therefore recommended that members of the SMT be exposed to continuing professional training and development in the aforementioned governance areas.
- Full Text:
- Date Issued: 2011
- Authors: Mapisa, Bafundi Zealous
- Date: 2011
- Subjects: School management -- Education and training
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:18423 , http://hdl.handle.net/11260/d1006923
- Description: During the apartheid era, that is, before 1994, principals tended to regard schools as their properties. Principals were expected to manage schools on their own without consulting the rest of the staff. From 1994 with the advent of a new political era, South Africa ended up having one National Education System. That system came up with many changes. In the new education system, the management of the school was taken from being the principal‟s duty only, to the responsibility of a management team which is referred to as the school management team (SMT). Because of the democratic nature of the SMT, it is required that educators work co-operatively as a team. The researcher has observed that this has been a challenge in some schools where principals resisted change. On the other hand, principals of schools are facing challenges due to a lack of cooperation amongst their subordinates. The establishment of SMTs does not nullify the authority of the school principal but the challenge that lies therein is that each member of the SMT must play his or her role properly. The purpose of this study was to explore the challenges facing SMT members in the GET band schools of Circuit 2 in Centane. A qualitative investigation was undertaken with the purpose in mind to develop a better understanding of the challenges facing SMTs in Circuit 2. This study was undertaken among 5 schools in Circuit 2 in Centane which falls under Butterworth District. The researcher used convenience sampling in selecting the SMTs of schools that would participate in this research study. Due to the fact that the researcher is a principal in one of the schools in Circuit 2 he could obtain easy access to SMTs of other schools in the Circuit. The following stakeholders were identified and participated in the selected schools: principal, deputy principal and Head of Department. Qualitative data were collected through semi- structured interviews. The study was framed within the interpretive approach, and sought to unpack the perceptions of SMT members with regard to team-management . An interpretive paradigm made it possible for the researcher to gain an in-depth understanding of SMT members‟ perceptions of team-management within their contexts. The outcomes pointed to several challenges ranging from the SMT terms of reference, cooperation, sources of support and stress as a result of the work overload involved. Based on the findings, SMTs have brought the phenomenon of cooperation to the fore, and cooperation may be perceived to have many advantages. However, in order for the SMTs to play a meaningful role in curriculum management and governance issues, there is a need for them to be conversant with issues and kept abreast of developments in education as a system. It is therefore recommended that members of the SMT be exposed to continuing professional training and development in the aforementioned governance areas.
- Full Text:
- Date Issued: 2011
Challenging the forked tongue of multilingualism: scholarship in African languages at SA Universities with specific reference to Rhodes
- Authors: Kaschula, Russell H
- Date: 2011
- Language: English
- Type: Text
- Identifier: vital:586 , http://hdl.handle.net/10962/d1018946 , https://orcid.org/0000-0002-5481-6748
- Description: [From the text] Effective multilingualism will aid SA in creating Social Cohesion (cultural, linguistic), a National Government initiative forming part of language planning. Languages should be seen as part of our environment and “resource package” within an intercultural paradigm. All students exiting School and University must be proficient in an African language and English or Afrikaans.
- Full Text:
- Date Issued: 2011
- Authors: Kaschula, Russell H
- Date: 2011
- Language: English
- Type: Text
- Identifier: vital:586 , http://hdl.handle.net/10962/d1018946 , https://orcid.org/0000-0002-5481-6748
- Description: [From the text] Effective multilingualism will aid SA in creating Social Cohesion (cultural, linguistic), a National Government initiative forming part of language planning. Languages should be seen as part of our environment and “resource package” within an intercultural paradigm. All students exiting School and University must be proficient in an African language and English or Afrikaans.
- Full Text:
- Date Issued: 2011
Characterization and electrocatalytic applications of metallophthalocyanine-single walled carbon nanotube conjugates
- Authors: Mugadza, Tawanda
- Date: 2011 , 2011-03-30
- Subjects: Phthalocyanines Pesticides Nanotubes Electrocatalysis Electrochemistry Transmission electron microscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4419 , http://hdl.handle.net/10962/d1006855
- Description: Metallophthalocyanine-single walled carbon nanotube conjugates were successfully synthesized and applied in the electrochemical characterizations of pesticides (amitrole and diuron) and 2-mercaptoethanol (2-ME). The formation of conjugates was confirmed through the use of the following analytical techniques: UV-vis, FTIR, Raman and XRD spectroscopies, atomic force and transmission electron microscopies and voltammetry. Chemically linking SWCNT to MPcs created platforms that offered efficient transfer of electrons and this was confirmed through electrochemical impedance studies (EIS) and voltammetry as shown by lower ΔEp values observed in conjugates. Carboxy carrying MPcs have very poor electron transfer kinetics (both tetrasubstituted and low symmetry), but the presence of SWCNTs activates their catalysis. All electrochemical studies were done at pH 4. Cyclic voltammetry, rotating disk linear sweep voltammetry, chronoamperometry and EIS were used in the electrochemical characterization of 2-ME and the pesticides on poly-Ni(OH)TAPc and MPc-SWCNT modified glassy carbon electrodes (GCEs). High Tafel slopes were observed for the pesticides relative to 2-ME, an indication of the passivating nature of their oxidation products. However, conjugates showed very high resistances to passivation and were easily regenerated by shaking in methanol. Improved catalysis of the conjugates is also indicated by the high catalytic rate constants for the analytes, observed on these electrodes. Conjugates of low symmetry MPcs with SWCNTs gave the highest catalytic rate constants, confirming better catalysis on these electrode surfaces. The nature of SWCNT functionalization also affected catalysis, with amine functionalized SWCNTs inducing better catalytic properties into the MPcs than carboxylic acid terminated CNTs. The presence of amine functionalized SWCNTs activates the catalysis of non-catalytic carboxy-carrying MPcs and this is more pronounced in conjugates of tetrasubstituted MPcs relative to those of low symmetry Pcs. Ethylene amine (EA) functionalized SWCNTs reduced redox overpotentials of the MPcs more than the phenyl-amine (PA) functionalized counterparts. Poly-NiTAPc was successfully converted to poly-Ni(OH)TAPc through cyclisation in pH 4 buffer and showed very good catalytic properties towards diuron, relative to the former.
- Full Text:
- Date Issued: 2011
- Authors: Mugadza, Tawanda
- Date: 2011 , 2011-03-30
- Subjects: Phthalocyanines Pesticides Nanotubes Electrocatalysis Electrochemistry Transmission electron microscopy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4419 , http://hdl.handle.net/10962/d1006855
- Description: Metallophthalocyanine-single walled carbon nanotube conjugates were successfully synthesized and applied in the electrochemical characterizations of pesticides (amitrole and diuron) and 2-mercaptoethanol (2-ME). The formation of conjugates was confirmed through the use of the following analytical techniques: UV-vis, FTIR, Raman and XRD spectroscopies, atomic force and transmission electron microscopies and voltammetry. Chemically linking SWCNT to MPcs created platforms that offered efficient transfer of electrons and this was confirmed through electrochemical impedance studies (EIS) and voltammetry as shown by lower ΔEp values observed in conjugates. Carboxy carrying MPcs have very poor electron transfer kinetics (both tetrasubstituted and low symmetry), but the presence of SWCNTs activates their catalysis. All electrochemical studies were done at pH 4. Cyclic voltammetry, rotating disk linear sweep voltammetry, chronoamperometry and EIS were used in the electrochemical characterization of 2-ME and the pesticides on poly-Ni(OH)TAPc and MPc-SWCNT modified glassy carbon electrodes (GCEs). High Tafel slopes were observed for the pesticides relative to 2-ME, an indication of the passivating nature of their oxidation products. However, conjugates showed very high resistances to passivation and were easily regenerated by shaking in methanol. Improved catalysis of the conjugates is also indicated by the high catalytic rate constants for the analytes, observed on these electrodes. Conjugates of low symmetry MPcs with SWCNTs gave the highest catalytic rate constants, confirming better catalysis on these electrode surfaces. The nature of SWCNT functionalization also affected catalysis, with amine functionalized SWCNTs inducing better catalytic properties into the MPcs than carboxylic acid terminated CNTs. The presence of amine functionalized SWCNTs activates the catalysis of non-catalytic carboxy-carrying MPcs and this is more pronounced in conjugates of tetrasubstituted MPcs relative to those of low symmetry Pcs. Ethylene amine (EA) functionalized SWCNTs reduced redox overpotentials of the MPcs more than the phenyl-amine (PA) functionalized counterparts. Poly-NiTAPc was successfully converted to poly-Ni(OH)TAPc through cyclisation in pH 4 buffer and showed very good catalytic properties towards diuron, relative to the former.
- Full Text:
- Date Issued: 2011
Characterization of stratified L-topological spaces by convergence of stratified L-filters
- Authors: Orpen, David Lisle
- Date: 2011
- Subjects: Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5402 , http://hdl.handle.net/10962/d1005216 , Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Description: For the case where L is an ecl-premonoid, we explore various characterizations of SL-topological spaces, in particular characterization in terms of a convergence function lim: FS L(X) ! LX. We find we have to introduce a new axiom , L on the lim function in order to completely describe SL-topological spaces, which is not required in the case where L is a frame. We generalize the classical Kowalski and Fischer axioms to the lattice context and examine their relationship to the convergence axioms. We define the category of stratified L-generalized convergence spaces, as a generalization of the classical convergence spaces and investigate conditions under which it contains the category of stratified L-topological spaces as a reflective subcategory. We investigate some subcategories of the category of stratified L-generalized convergence spaces obtained by generalizing various classical convergence axioms.
- Full Text:
- Date Issued: 2011
- Authors: Orpen, David Lisle
- Date: 2011
- Subjects: Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5402 , http://hdl.handle.net/10962/d1005216 , Topology , Generalized spaces , Filters (Mathematics) , Topological spaces
- Description: For the case where L is an ecl-premonoid, we explore various characterizations of SL-topological spaces, in particular characterization in terms of a convergence function lim: FS L(X) ! LX. We find we have to introduce a new axiom , L on the lim function in order to completely describe SL-topological spaces, which is not required in the case where L is a frame. We generalize the classical Kowalski and Fischer axioms to the lattice context and examine their relationship to the convergence axioms. We define the category of stratified L-generalized convergence spaces, as a generalization of the classical convergence spaces and investigate conditions under which it contains the category of stratified L-topological spaces as a reflective subcategory. We investigate some subcategories of the category of stratified L-generalized convergence spaces obtained by generalizing various classical convergence axioms.
- Full Text:
- Date Issued: 2011
Characterization of village chicken health and management practices in the Amatola Basin of the Eastern Cape Province of South Afrrica
- Nyoni, Njongenhle Mhlanhlandlela Bernard
- Authors: Nyoni, Njongenhle Mhlanhlandlela Bernard
- Date: 2011
- Subjects: Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11804 , http://hdl.handle.net/10353/561 , Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Description: Characterization of village chicken phealth and management practices in the Amatola Basin of the Eastern Cape Province, South Africa By Njongenhle M. B. NYONI The majority of rural households in South Africa own village chickens which contribute significantly to their livelihoods. However, limited research has been conducted to characterize, understand and develop village chicken production in South Africa. This hinders the designing and implementation of village chicken-based developmental programmes that will benefit farmers in rural areas. Thus, it is imperative to initiate studies to describe village chicken production. This study was conducted to characterize village chicken production in Amatola Basin of the Eastern Cape Province of South Africa. Baseline information was gathered using a questionnaire survey of 81 identified from 7 out of 13 villages using snowball sampling technique. Consequently, 20 households were selected to participate in a monitoring study (from July 2010 to June 2011) through purposive sampling. Most (60%) chicken flocks were owned by women and mainly raised to meet household food requirements. Some (28.4%) farmers occasionally sold cocks and hens to neighbours, at an average price of R50 (USD7.55) per bird, as a way of culling their flocks and generating income. However, village chickens were mainly kept for food security rather than for their terminal benefit of cash. Although, all chicken flocks were produced under the scavenging feeding system, most (96%) flocks were provided with supplementary feed and drinking water. A majority (93.8%) of households also provided some form of shelter for their chickens. The mean cock to hen to chick ratio was 1:5:15. On average, iii each household owned 17 (±2 S.E.M.) chickens, and hens had 3.3 clutches per annum. Chicks hatched and chickens received as gifts represented the flock entries, while exits included mortality, consumption, sales and gifts or donations, in that order. Generally, both exits and entries were more pronounced in the summer season than in other seasons. Most (81.5%) farmers experienced chicken losses due to predation and health related problems. Parasitism ranked high amongst the village chicken health challenges. During monitoring, the endoprasites identified included nematodes, cestodes and protozoa. Coccidia were the most prevalent endoparasites. The chickens were also infested with a variety of ectoparasites namely: mites, lice, fleas and ticks. The sticktight flea Echidnophaga gallinacean was the most prevalent species. Although ectoparasite infestations were most pronounced in summer, almost all chickens harbored one or more of these parasites throughout the study period. The prevalence and intensity of parasite infestations were significantly (P<0.05) higher in the summer season compared to the other seasons. This was followed by the autumn, spring and winter seasons, respectively. The majority (77.5%) of farmers resorted to alternative remedies, mostly medicinal plants, for treating diseases and controlling parasites. Medicinal plants were used because they were locally available, cheap and perceived to be effective. Therefore, village chicken production in the rural Eastern Cape Province is characterised by several challenges which counter the significant role chickens play in the livelihood of rural households.
- Full Text:
- Date Issued: 2011
- Authors: Nyoni, Njongenhle Mhlanhlandlela Bernard
- Date: 2011
- Subjects: Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11804 , http://hdl.handle.net/10353/561 , Chickens -- Diseases , Chickens -- Health , Chickens -- Parasites , Chickens -- South Africa -- Eastern Cape
- Description: Characterization of village chicken phealth and management practices in the Amatola Basin of the Eastern Cape Province, South Africa By Njongenhle M. B. NYONI The majority of rural households in South Africa own village chickens which contribute significantly to their livelihoods. However, limited research has been conducted to characterize, understand and develop village chicken production in South Africa. This hinders the designing and implementation of village chicken-based developmental programmes that will benefit farmers in rural areas. Thus, it is imperative to initiate studies to describe village chicken production. This study was conducted to characterize village chicken production in Amatola Basin of the Eastern Cape Province of South Africa. Baseline information was gathered using a questionnaire survey of 81 identified from 7 out of 13 villages using snowball sampling technique. Consequently, 20 households were selected to participate in a monitoring study (from July 2010 to June 2011) through purposive sampling. Most (60%) chicken flocks were owned by women and mainly raised to meet household food requirements. Some (28.4%) farmers occasionally sold cocks and hens to neighbours, at an average price of R50 (USD7.55) per bird, as a way of culling their flocks and generating income. However, village chickens were mainly kept for food security rather than for their terminal benefit of cash. Although, all chicken flocks were produced under the scavenging feeding system, most (96%) flocks were provided with supplementary feed and drinking water. A majority (93.8%) of households also provided some form of shelter for their chickens. The mean cock to hen to chick ratio was 1:5:15. On average, iii each household owned 17 (±2 S.E.M.) chickens, and hens had 3.3 clutches per annum. Chicks hatched and chickens received as gifts represented the flock entries, while exits included mortality, consumption, sales and gifts or donations, in that order. Generally, both exits and entries were more pronounced in the summer season than in other seasons. Most (81.5%) farmers experienced chicken losses due to predation and health related problems. Parasitism ranked high amongst the village chicken health challenges. During monitoring, the endoprasites identified included nematodes, cestodes and protozoa. Coccidia were the most prevalent endoparasites. The chickens were also infested with a variety of ectoparasites namely: mites, lice, fleas and ticks. The sticktight flea Echidnophaga gallinacean was the most prevalent species. Although ectoparasite infestations were most pronounced in summer, almost all chickens harbored one or more of these parasites throughout the study period. The prevalence and intensity of parasite infestations were significantly (P<0.05) higher in the summer season compared to the other seasons. This was followed by the autumn, spring and winter seasons, respectively. The majority (77.5%) of farmers resorted to alternative remedies, mostly medicinal plants, for treating diseases and controlling parasites. Medicinal plants were used because they were locally available, cheap and perceived to be effective. Therefore, village chicken production in the rural Eastern Cape Province is characterised by several challenges which counter the significant role chickens play in the livelihood of rural households.
- Full Text:
- Date Issued: 2011
Childhood development and career development in eight year-old South African girls
- Van der Westhuyzen, Nicole Tamsin
- Authors: Van der Westhuyzen, Nicole Tamsin
- Date: 2011
- Subjects: Childhood development , Career development , Griffiths scales of mental development , Early childhood education -- Vocational guidance -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9942 , http://hdl.handle.net/10948/d1012969
- Description: Although it is generally acknowledged that critical career-related concepts and attitudes are first formed in childhood, research has focused little attention on this developmental stage. Statements about children‘s career development as an integral dimension of human development date to the early 1950s, yet limited research has investigated this interrelationship. It is imperative to gain a greater understanding of childhood career development in order to better prepare children for their future. The overall purpose of this study is to explore the interrelationship of childhood development and childhood career development. An exploratory-descriptive quantitative research method was used. Thirty participants (all eight year-old girls from a middle class, English speaking background) were selected through non-probability purposive sampling. Data were gathered from the Griffiths Mental Development Scales – Extended Revised (GMDS-ER) and the Childhood Career Development Scale (CCDS) and analysed using descriptive and inferential statistics. The results indicated a correlation, although not statistically significant, between childhood development and childhood career development, thus indicating a weak positive correlation between the two variables. Statistically significant relationships were established between certain subscales of the GMDS-ER and CCDS, namely Language and Exploration, Eye-Hand Co-ordination and Key Figures, and Practical Reasoning and Planning. The results from this study, although not conclusive, are groundbreaking in this neglected area of research as they indicate an interrelationship between childhood development and childhood career development. This research is an initial step in investigating this interrelationship and it is the hope of the researcher that it will stimulate further research in this area.
- Full Text:
- Date Issued: 2011
- Authors: Van der Westhuyzen, Nicole Tamsin
- Date: 2011
- Subjects: Childhood development , Career development , Griffiths scales of mental development , Early childhood education -- Vocational guidance -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9942 , http://hdl.handle.net/10948/d1012969
- Description: Although it is generally acknowledged that critical career-related concepts and attitudes are first formed in childhood, research has focused little attention on this developmental stage. Statements about children‘s career development as an integral dimension of human development date to the early 1950s, yet limited research has investigated this interrelationship. It is imperative to gain a greater understanding of childhood career development in order to better prepare children for their future. The overall purpose of this study is to explore the interrelationship of childhood development and childhood career development. An exploratory-descriptive quantitative research method was used. Thirty participants (all eight year-old girls from a middle class, English speaking background) were selected through non-probability purposive sampling. Data were gathered from the Griffiths Mental Development Scales – Extended Revised (GMDS-ER) and the Childhood Career Development Scale (CCDS) and analysed using descriptive and inferential statistics. The results indicated a correlation, although not statistically significant, between childhood development and childhood career development, thus indicating a weak positive correlation between the two variables. Statistically significant relationships were established between certain subscales of the GMDS-ER and CCDS, namely Language and Exploration, Eye-Hand Co-ordination and Key Figures, and Practical Reasoning and Planning. The results from this study, although not conclusive, are groundbreaking in this neglected area of research as they indicate an interrelationship between childhood development and childhood career development. This research is an initial step in investigating this interrelationship and it is the hope of the researcher that it will stimulate further research in this area.
- Full Text:
- Date Issued: 2011
Climate change adaptation and economic valuation of local pig genetic resources in communal production systems of South Africa
- Authors: Madzimure, James
- Date: 2011
- Subjects: Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11805 , http://hdl.handle.net/10353/427 , Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Description: The broad objective of the study was to determine the economic value of local pigs in marketand subsistence-oriented production systems in communal areas of Southern Africa. Data were collected from 288 households to investigate farmer perceptions, effects on pig production and handling of disease outbreaks such as classical swine fever (CSF) in market- and subsistenceoriented production systems. The utilisation of local pigs in these market- and subsistenceoriented production systems in improving people‟s welfare was evaluated. Climate change was identified by farmers in these production systems as a major constraint to pig production hence an experiment was carried out in the hottest season to determine diurnal heat-related physiological and behavioural responses in Large White (LW) and South African local pigs. The same genotypes were used to determine effects of diurnal heat-related stress on their growth performance. Choice experiment was done to determine farmer preferences for local pig traits and implicit prices for these traits in CSF-affected and unaffected areas that were under subsistence- and market-oriented production systems. In this experiment, the importance of heat tolerance was assessed relative to other productive and climate change adaptation traits. Significantly more pigs were culled in the CSF-affected areas that were market-oriented (8.0 ± 1.76) than subsistence-oriented (4.1 ± 1.00) production system. The risk of parasites and disease challenges was high in subsistence-oriented production system and coastal areas. In both production systems, CSF was perceived as destructive since the culling of pigs affected pork availability and income generation. The high risk of disease outbreaks and threat of climate change caused farmers in subsistence-oriented production system to select local pigs for their adaptive traits while those in the market-oriented production system focused on productive imported pigs. Farmers (83 %) indicated that they wanted pig genotypes that were adapted to climate change effects such as hot conditions. Local pigs were found to have superior heat tolerance over LW pigs (P < 0.05) in terms of lower heart rate and skin surface temperature. Frequency per day and duration for behavioural heat loss activities such as wallowing, sleeping in a prostrate posture and sprawling in slurry were also lower (P < 0.05) for local than LW pigs. The superiority of heat tolerance of local over LW pigs was further confirmed by their uncompromised growth performance under high diurnal temperatures. The Pearson‟s product moment correlation coefficient between temperature and feed conversion ratio for LW pigs was strongly positive (r = 0.50; P < 0.001) unlike the weak and positive correlation for local pigs (r = 0.20; P < 0.05). There was a quadratic relationship between temperature and average daily gain (ADG) for both pig genotypes. The regression coefficients for ADG were higher (P < 0.001) for LW than local pigs. It was concluded that at high ambient temperatures, performance of local pigs was less compromised than for LW pigs. Although local pigs were found to be heat tolerant, results of choice experiment showed that this trait was not selected for relative to other traits. Keeping pigs that required bought-in feeds, fell sick often and produced low pork quality (eating quality based on farmer perceptions) negatively affected farmers‟ livelihoods more in subsistence- than market-oriented production system. Farmers in market-oriented production system derived more benefit from productive traits such as heavier slaughter weights and large litter size than subsistence-oriented farmers. Under the subsistence-oriented production system, farmers in CSF-affected areas placed high prices on adaptive traits than the unaffected areas. Subsistence-oriented farmers who were affected by CSF wanted a total compensation price of R10 944.00 (USD1563.43) for keeping a pig genotype with unfavourable traits when compared to R4235.00 (USD605.00) for their CSF-unaffected counterparts. Implicit prices for traits could not be determined for market-oriented production system. It was concluded that farmers in CSFaffected areas placed high economic values on pig traits than farmers from the CSF-unaffected areas. The findings suggest that adapted local pigs can be promoted in subsistence-oriented production systems while productive imported pigs and their crosses with local pigs can be kept in market-oriented production systems.
- Full Text:
- Date Issued: 2011
- Authors: Madzimure, James
- Date: 2011
- Subjects: Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11805 , http://hdl.handle.net/10353/427 , Swine -- Breeding -- South Africa , Swine -- Feeding and feeds -- South Africa , Swine -- Genetics , Swine -- Nutrition -- Requirements , Climate change mitigation -- Environmental aspects , Swine -- Diseases -- South Africa , Commons -- Conservation --South Africa , Natural resources, Communal -- Management , Genotype-environment interaction -- South Africa
- Description: The broad objective of the study was to determine the economic value of local pigs in marketand subsistence-oriented production systems in communal areas of Southern Africa. Data were collected from 288 households to investigate farmer perceptions, effects on pig production and handling of disease outbreaks such as classical swine fever (CSF) in market- and subsistenceoriented production systems. The utilisation of local pigs in these market- and subsistenceoriented production systems in improving people‟s welfare was evaluated. Climate change was identified by farmers in these production systems as a major constraint to pig production hence an experiment was carried out in the hottest season to determine diurnal heat-related physiological and behavioural responses in Large White (LW) and South African local pigs. The same genotypes were used to determine effects of diurnal heat-related stress on their growth performance. Choice experiment was done to determine farmer preferences for local pig traits and implicit prices for these traits in CSF-affected and unaffected areas that were under subsistence- and market-oriented production systems. In this experiment, the importance of heat tolerance was assessed relative to other productive and climate change adaptation traits. Significantly more pigs were culled in the CSF-affected areas that were market-oriented (8.0 ± 1.76) than subsistence-oriented (4.1 ± 1.00) production system. The risk of parasites and disease challenges was high in subsistence-oriented production system and coastal areas. In both production systems, CSF was perceived as destructive since the culling of pigs affected pork availability and income generation. The high risk of disease outbreaks and threat of climate change caused farmers in subsistence-oriented production system to select local pigs for their adaptive traits while those in the market-oriented production system focused on productive imported pigs. Farmers (83 %) indicated that they wanted pig genotypes that were adapted to climate change effects such as hot conditions. Local pigs were found to have superior heat tolerance over LW pigs (P < 0.05) in terms of lower heart rate and skin surface temperature. Frequency per day and duration for behavioural heat loss activities such as wallowing, sleeping in a prostrate posture and sprawling in slurry were also lower (P < 0.05) for local than LW pigs. The superiority of heat tolerance of local over LW pigs was further confirmed by their uncompromised growth performance under high diurnal temperatures. The Pearson‟s product moment correlation coefficient between temperature and feed conversion ratio for LW pigs was strongly positive (r = 0.50; P < 0.001) unlike the weak and positive correlation for local pigs (r = 0.20; P < 0.05). There was a quadratic relationship between temperature and average daily gain (ADG) for both pig genotypes. The regression coefficients for ADG were higher (P < 0.001) for LW than local pigs. It was concluded that at high ambient temperatures, performance of local pigs was less compromised than for LW pigs. Although local pigs were found to be heat tolerant, results of choice experiment showed that this trait was not selected for relative to other traits. Keeping pigs that required bought-in feeds, fell sick often and produced low pork quality (eating quality based on farmer perceptions) negatively affected farmers‟ livelihoods more in subsistence- than market-oriented production system. Farmers in market-oriented production system derived more benefit from productive traits such as heavier slaughter weights and large litter size than subsistence-oriented farmers. Under the subsistence-oriented production system, farmers in CSF-affected areas placed high prices on adaptive traits than the unaffected areas. Subsistence-oriented farmers who were affected by CSF wanted a total compensation price of R10 944.00 (USD1563.43) for keeping a pig genotype with unfavourable traits when compared to R4235.00 (USD605.00) for their CSF-unaffected counterparts. Implicit prices for traits could not be determined for market-oriented production system. It was concluded that farmers in CSFaffected areas placed high economic values on pig traits than farmers from the CSF-unaffected areas. The findings suggest that adapted local pigs can be promoted in subsistence-oriented production systems while productive imported pigs and their crosses with local pigs can be kept in market-oriented production systems.
- Full Text:
- Date Issued: 2011
Climate‐driven genetic divergence of limpets with different life histories across a southeast African marine biogeographic disjunction: different processes, same outcome
- Teske, Peter R, Papadopoulos, Isabelle, Mmonwa, Kolobe L, Matumba, Tshifhiwa G, McQuaid, Christopher D, Barker, Nigel P, Beheregaray, Luciano B
- Authors: Teske, Peter R , Papadopoulos, Isabelle , Mmonwa, Kolobe L , Matumba, Tshifhiwa G , McQuaid, Christopher D , Barker, Nigel P , Beheregaray, Luciano B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445420 , vital:74385 , https://doi.org/10.1111/j.1365-294X.2011.05307.x
- Description: Genetic divergence among populations of marine broadcast spawners in the absence of past geological barriers presents an intriguing challenge to understanding speciation in the sea. To determine how differences in life history affect genetic divergence and demographic histories across incomplete dispersal barriers, we conducted a comparative phylogeographic study of three intertidal limpets (Siphonaria spp.) represented on either side of a biogeographic disjunction separating tropical and subtropical marine provinces in southeastern Africa. Using a combination of mitochondrial and nuclear sequence data, we identified two distinct evolutionary lineages each in both Siphonaria concinna (a planktonic disperser) and S. nigerrima (a direct developer), and panmixia in a second planktonic disperser, S. capensis.
- Full Text:
- Date Issued: 2011
- Authors: Teske, Peter R , Papadopoulos, Isabelle , Mmonwa, Kolobe L , Matumba, Tshifhiwa G , McQuaid, Christopher D , Barker, Nigel P , Beheregaray, Luciano B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445420 , vital:74385 , https://doi.org/10.1111/j.1365-294X.2011.05307.x
- Description: Genetic divergence among populations of marine broadcast spawners in the absence of past geological barriers presents an intriguing challenge to understanding speciation in the sea. To determine how differences in life history affect genetic divergence and demographic histories across incomplete dispersal barriers, we conducted a comparative phylogeographic study of three intertidal limpets (Siphonaria spp.) represented on either side of a biogeographic disjunction separating tropical and subtropical marine provinces in southeastern Africa. Using a combination of mitochondrial and nuclear sequence data, we identified two distinct evolutionary lineages each in both Siphonaria concinna (a planktonic disperser) and S. nigerrima (a direct developer), and panmixia in a second planktonic disperser, S. capensis.
- Full Text:
- Date Issued: 2011
Co-utilisation of microalgae for wastewater treatment and the production of animal feed supplements
- Authors: Johnson, Hailey E
- Date: 2011
- Subjects: Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3940 , http://hdl.handle.net/10962/d1003999 , Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Description: Microalgae have a variety of commercial applications, the oldest of which include utilisation as a food source and for use in wastewater treatment. These applications, however, are seldom combined due to toxicity concerns, for ethical reasons, and generally the requirement for cultivation of a single algae species for use as a feed supplement. These problems might be negated if a “safer” wastewater such as that from agricultural and/or commercial food production facilities were to be utilised and if a stable algae population can be maintained. In this investigation preliminary studies were carried out using an Integrated Algae Pond System (IAPS) for domestic wastewater treatment to determine the species composition in the associated High Rate Algae Ponds (HRAPs). The effect of different modes of operation, continuous versus batch, on nutrient removal, productivity and species composition was also investigated. Furthermore, indigenous species in the HRAP were isolated and molecularly identified as, Chlorella, Micractinium, Scenedesmus and Pediastrum. Additionally, the effect of the nor amino acid, 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) and its Cu-chelated derivative, on the growth and biochemical composition of Chlorella, Micractinium, Scenedesmus, Pediastrum and Spirulina was investigated. Species composition in the HRAP was stable under continuous operation with Micractinium dominating > 90% of the algae population. Under batch operation the population dynamic shifted; Chlorella outcompeted Micractinium possibly due to nutrient depletion and selective grazing pressures caused by proliferation of Daphnia. Higher species diversity was observed during batch mode as slower growing algae were able to establish in the HRAP. Nutrient removal efficiency and biomass productivity was higher in continuous mode, however lower nutrient levels were obtained in batch operation. HMTBA did not significantly affect growth rate, however treatment with 10 mg.L-1 resulted in slightly increased growth rate in Micractinium and increased final biomass concentrations in Chlorella, Micractinium and Spirulina (although this was not statistically significant for Micractinium and Spirulina), which are known mixotrophic species. Algae treated with Cu-HMTBA, showed reduced final biomass concentration with 10 mg.L-1, caused by Cu toxicity. Biochemical composition of the algae was species-specific and differed through the growth cycle, with high protein observed during early growth and high carbohydrate during late growth/early stationary phase. Additionally, 0.1 mg.L-1 HMTBA and Cu-HMTBA significantly reduced protein content in Chlorella, Micractinium, Scenedesmus and Pediastrum. In conclusion, operation of the HRAP in continuous culture provided suitable wastewater treatment with high productivity of an ideal species, Micractinium, for use in animal feed supplementation. This species had 40% protein content during growth (higher than the other species tested) and dominated the HRAP at > 90% of the algae population during continuous mode. Addition of HMTBA (> 1 mg.L-1) to algae cultivation systems and those treating wastewater, has the potential to improve productivity and the value of the biomass by enhancing protein content. Overall, the co-utilisation of microalgae for wastewater treatment and the generation of a biomass rich in protein, for incorporation into formulated animal feed supplements, represents a closed ecosystem which conserves nutrients and regenerates a most valuable resource, water.
- Full Text:
- Date Issued: 2011
- Authors: Johnson, Hailey E
- Date: 2011
- Subjects: Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3940 , http://hdl.handle.net/10962/d1003999 , Microalgae -- Biotechnology , Algae culture , Algae products , Waste products as feed , Sewage -- Purification , Organic wastes -- Recycling , Food industry and trade -- Waste disposal , Agriculture -- Waste disposal
- Description: Microalgae have a variety of commercial applications, the oldest of which include utilisation as a food source and for use in wastewater treatment. These applications, however, are seldom combined due to toxicity concerns, for ethical reasons, and generally the requirement for cultivation of a single algae species for use as a feed supplement. These problems might be negated if a “safer” wastewater such as that from agricultural and/or commercial food production facilities were to be utilised and if a stable algae population can be maintained. In this investigation preliminary studies were carried out using an Integrated Algae Pond System (IAPS) for domestic wastewater treatment to determine the species composition in the associated High Rate Algae Ponds (HRAPs). The effect of different modes of operation, continuous versus batch, on nutrient removal, productivity and species composition was also investigated. Furthermore, indigenous species in the HRAP were isolated and molecularly identified as, Chlorella, Micractinium, Scenedesmus and Pediastrum. Additionally, the effect of the nor amino acid, 2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) and its Cu-chelated derivative, on the growth and biochemical composition of Chlorella, Micractinium, Scenedesmus, Pediastrum and Spirulina was investigated. Species composition in the HRAP was stable under continuous operation with Micractinium dominating > 90% of the algae population. Under batch operation the population dynamic shifted; Chlorella outcompeted Micractinium possibly due to nutrient depletion and selective grazing pressures caused by proliferation of Daphnia. Higher species diversity was observed during batch mode as slower growing algae were able to establish in the HRAP. Nutrient removal efficiency and biomass productivity was higher in continuous mode, however lower nutrient levels were obtained in batch operation. HMTBA did not significantly affect growth rate, however treatment with 10 mg.L-1 resulted in slightly increased growth rate in Micractinium and increased final biomass concentrations in Chlorella, Micractinium and Spirulina (although this was not statistically significant for Micractinium and Spirulina), which are known mixotrophic species. Algae treated with Cu-HMTBA, showed reduced final biomass concentration with 10 mg.L-1, caused by Cu toxicity. Biochemical composition of the algae was species-specific and differed through the growth cycle, with high protein observed during early growth and high carbohydrate during late growth/early stationary phase. Additionally, 0.1 mg.L-1 HMTBA and Cu-HMTBA significantly reduced protein content in Chlorella, Micractinium, Scenedesmus and Pediastrum. In conclusion, operation of the HRAP in continuous culture provided suitable wastewater treatment with high productivity of an ideal species, Micractinium, for use in animal feed supplementation. This species had 40% protein content during growth (higher than the other species tested) and dominated the HRAP at > 90% of the algae population during continuous mode. Addition of HMTBA (> 1 mg.L-1) to algae cultivation systems and those treating wastewater, has the potential to improve productivity and the value of the biomass by enhancing protein content. Overall, the co-utilisation of microalgae for wastewater treatment and the generation of a biomass rich in protein, for incorporation into formulated animal feed supplements, represents a closed ecosystem which conserves nutrients and regenerates a most valuable resource, water.
- Full Text:
- Date Issued: 2011
Cointegration in equity markets: a comparison between South African and major developed and emerging markets
- Authors: Petrov, Pavel
- Date: 2011
- Subjects: Cointegration Stock exchanges -- South Africa Stock exchanges -- Developing countries Stock exchanges -- Developed countries South Africa -- Economic conditions Portfolio management -- South Africa Econometrics Autoregression (Statistics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:5575 , http://hdl.handle.net/10962/d1005539
- Description: Cointegration has important implications for portfolio diversification. One of these is that in order to spread risk it is advisable to invest in markets that are not cointegrated. Over the last several decades communication technology has made the world a smaller place and hence cointegration in equity markets has become more prevalent. The bulk of research into cointegration focuses on developed and Asian markets, with little research been done on African markets. This study compares the Engle-Granger and Johansen tests for cointegration and uses them to calculate the level of cointegration between South African and other global equity markets. Each market is compared pair-wise with South Africa and the results have been that in general South Africa is cointegrated with other emerging markets but not really with African nor developed markets. Short-run analysis with the error correction was carried out and showed that in general markets respond slowly to any disequilibrium. Innovation accounting methods showed that the country placed first in Cholesky ordering dominates the other one. Multivariate cointegration was carried out using three selections of 4, 6 and 8 market portfolios. One of the markets was SA and the others were all chosen based on the criteria that they are not pair-wise cointegrated with SA. The level of cointegration varied depending on the portfolios, as did the error correction rates, impulse responses and variance decomposition. The one constant was that the USA dominated any portfolio where it was introduced. Recommendations were finally made about which market portfolio an investor should consider as most favourable.
- Full Text:
- Date Issued: 2011
- Authors: Petrov, Pavel
- Date: 2011
- Subjects: Cointegration Stock exchanges -- South Africa Stock exchanges -- Developing countries Stock exchanges -- Developed countries South Africa -- Economic conditions Portfolio management -- South Africa Econometrics Autoregression (Statistics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:5575 , http://hdl.handle.net/10962/d1005539
- Description: Cointegration has important implications for portfolio diversification. One of these is that in order to spread risk it is advisable to invest in markets that are not cointegrated. Over the last several decades communication technology has made the world a smaller place and hence cointegration in equity markets has become more prevalent. The bulk of research into cointegration focuses on developed and Asian markets, with little research been done on African markets. This study compares the Engle-Granger and Johansen tests for cointegration and uses them to calculate the level of cointegration between South African and other global equity markets. Each market is compared pair-wise with South Africa and the results have been that in general South Africa is cointegrated with other emerging markets but not really with African nor developed markets. Short-run analysis with the error correction was carried out and showed that in general markets respond slowly to any disequilibrium. Innovation accounting methods showed that the country placed first in Cholesky ordering dominates the other one. Multivariate cointegration was carried out using three selections of 4, 6 and 8 market portfolios. One of the markets was SA and the others were all chosen based on the criteria that they are not pair-wise cointegrated with SA. The level of cointegration varied depending on the portfolios, as did the error correction rates, impulse responses and variance decomposition. The one constant was that the USA dominated any portfolio where it was introduced. Recommendations were finally made about which market portfolio an investor should consider as most favourable.
- Full Text:
- Date Issued: 2011
Cointegration, causality and international portfolio diversification : investigating potential benefits to a South African investor
- Authors: Msimanga, Nkululeko Lwazi
- Date: 2011
- Subjects: Cointegration , Econometrics , International finance , Stock exchanges -- South Africa , Stock exchanges -- Developing countries , Stock exchanges -- Developed countries , Investments -- South Africa , Portfolio management -- South Africa , Investment analysis , Autoregression (Statistics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:962 , http://hdl.handle.net/10962/d1002696 , Cointegration , Econometrics , International finance , Stock exchanges -- South Africa , Stock exchanges -- Developing countries , Stock exchanges -- Developed countries , Investments -- South Africa , Portfolio management -- South Africa , Investment analysis , Autoregression (Statistics)
- Description: Research studies on portfolio diversification have tended to focus on developed markets and paid less attention to emerging markets. Traditionally, correlation analysis has been used to determine potential benefits from diversification but current studies have shifted focus from correlation analysis to exploring cointegration analysis and other forms of tests such as the Vector Error Correction Methodology. The research seeks to find if it is beneficial for a South African investor to diversify their portfolio of emerging market equities over a long-term period. Daily weighted share indices for the period of January 1996 to November 2008 were collected and analysed through the application of the Johansen cointegration technique and Vector Error Correction Methodology. Granger Causality tests were also performed to established whether one variable can be useful in forecasting another variable. The study found that there was at least one statistically significant long-run relationship between the emerging markets. After testing for unit roots for all the share indices and their first difference using the Augmented Dickey-Fuller test (ADF), Philips-Perron and Kwiatkowski, Phillips, Schmidt, and Shin (KPSS) unit root tests, similar conclusions were m~de. All the unit root tests and their levels could not be rejected for all the series. However, unit root tests on the first differences were rejected, meaning that all series are of order 1(1) - evidence of cointegration. Simply put, emerging markets tend not to drift apart over time. This suggests that emerging markets offer limited benefits to investors who are looking to add some risk to their portfolios. In addition, the study also found evidence of both unidirectional and bidirectional causality (Granger-Cause tests) between markets. This implies that the conditions for a particular market are exogenous of the other market. The study concludes that emerging markets are gradually adopting the same profile as developed markets.
- Full Text:
- Date Issued: 2011
- Authors: Msimanga, Nkululeko Lwazi
- Date: 2011
- Subjects: Cointegration , Econometrics , International finance , Stock exchanges -- South Africa , Stock exchanges -- Developing countries , Stock exchanges -- Developed countries , Investments -- South Africa , Portfolio management -- South Africa , Investment analysis , Autoregression (Statistics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:962 , http://hdl.handle.net/10962/d1002696 , Cointegration , Econometrics , International finance , Stock exchanges -- South Africa , Stock exchanges -- Developing countries , Stock exchanges -- Developed countries , Investments -- South Africa , Portfolio management -- South Africa , Investment analysis , Autoregression (Statistics)
- Description: Research studies on portfolio diversification have tended to focus on developed markets and paid less attention to emerging markets. Traditionally, correlation analysis has been used to determine potential benefits from diversification but current studies have shifted focus from correlation analysis to exploring cointegration analysis and other forms of tests such as the Vector Error Correction Methodology. The research seeks to find if it is beneficial for a South African investor to diversify their portfolio of emerging market equities over a long-term period. Daily weighted share indices for the period of January 1996 to November 2008 were collected and analysed through the application of the Johansen cointegration technique and Vector Error Correction Methodology. Granger Causality tests were also performed to established whether one variable can be useful in forecasting another variable. The study found that there was at least one statistically significant long-run relationship between the emerging markets. After testing for unit roots for all the share indices and their first difference using the Augmented Dickey-Fuller test (ADF), Philips-Perron and Kwiatkowski, Phillips, Schmidt, and Shin (KPSS) unit root tests, similar conclusions were m~de. All the unit root tests and their levels could not be rejected for all the series. However, unit root tests on the first differences were rejected, meaning that all series are of order 1(1) - evidence of cointegration. Simply put, emerging markets tend not to drift apart over time. This suggests that emerging markets offer limited benefits to investors who are looking to add some risk to their portfolios. In addition, the study also found evidence of both unidirectional and bidirectional causality (Granger-Cause tests) between markets. This implies that the conditions for a particular market are exogenous of the other market. The study concludes that emerging markets are gradually adopting the same profile as developed markets.
- Full Text:
- Date Issued: 2011
Comfortably numb: Crump unveiled—a review of the 2011 Alan Crump retrospective exhibitio
- Authors: Cooper, Paul S
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147924 , vital:38685 , DOI:10.1080/00043389.2011.11877152
- Description: Writing can at times be difficult. It is not without considerable anxiety that I undertake to write this particular review. Perhaps I should offer a short qualifier: this is not strictly a review but rather a collection of ideas around the works and their arrangement, as well as my own musings and reflections on Crump. I want to pick up on what I identify to be an approach that personalises Crump as a professor, colleague and artist (we find this tone embedded throughout the accompanying exhibition catalogue). 1 I have chosen to structure this essay using a series of trigger headings, some provocative and possibly even inflammatory, others more neutral and concerned with getting to the core of what this retrospective and posthumous show is all about. All the while my thinking is to channel a sense (or lack thereof, as it may turn out) of my own experience of his work and person.
- Full Text:
- Date Issued: 2011
- Authors: Cooper, Paul S
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147924 , vital:38685 , DOI:10.1080/00043389.2011.11877152
- Description: Writing can at times be difficult. It is not without considerable anxiety that I undertake to write this particular review. Perhaps I should offer a short qualifier: this is not strictly a review but rather a collection of ideas around the works and their arrangement, as well as my own musings and reflections on Crump. I want to pick up on what I identify to be an approach that personalises Crump as a professor, colleague and artist (we find this tone embedded throughout the accompanying exhibition catalogue). 1 I have chosen to structure this essay using a series of trigger headings, some provocative and possibly even inflammatory, others more neutral and concerned with getting to the core of what this retrospective and posthumous show is all about. All the while my thinking is to channel a sense (or lack thereof, as it may turn out) of my own experience of his work and person.
- Full Text:
- Date Issued: 2011
Community development workers' perceptions of wellness at an HIV / AIDS organisation in Nelson Mandela Bay
- Authors: Ndlela, Joshua Bongani
- Date: 2011
- Subjects: Community development -- South Africa -- Eastern Cape , AIDS (Disease) -- South Africa -- Eastern Cape , HIV infections -- Social aspects -- South Africa -- Eastern Cape , Organisational behavior , Health promotion -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9837 , http://hdl.handle.net/10948/1657 , Community development -- South Africa -- Eastern Cape , AIDS (Disease) -- South Africa -- Eastern Cape , HIV infections -- Social aspects -- South Africa -- Eastern Cape , Organisational behavior , Health promotion -- South Africa -- Eastern Cape
- Description: The general aim of the study was to explore and describe community development workers` perceptions of wellness at an HIV/AIDS organisation in Nelson Mandela Bay, South Africa. The population of 36 community development workers at the Nelson Mandela Bay office of this organisation participated in this study. The sampling technique employed can be described as a census as it involved sampling an entire finite population that included all community development workers in the organisation. These workers are predominantly Xhosa-speaking adults between the ages of 21 and 60 years, and include both males and females. Qualitative data were gathered by means of audio-recorded focus groups, utilising semi-structured interviews. Tesch`s method was used to analyse the data, while Guba`s guidelines were used to enhance the trustworthiness of the research. Focus group interviews with community development workers revealed seven common themes in the experience of working in the HIV/AIDS organisation: (a) participants’ understanding of wellness; (b) organisational factors that impact on wellness; (c) personal factors that impact on wellness; (d) family and community factors that impact on wellness; (e) participants’ wellness; (f) personal coping strategies; and (g) suggestions regarding organisational strategies to enhance employee wellness. It is envisaged that the research findings of this study will be used in future to direct interventions that will be beneficial for the short and long term planning for the wellness of the community development workers of the HIV/AIDS organisation and those around them. It was recommended that the organisation was to develop a workplace wellness programme, increase management support towards the staff wellness and to increase the staff capacity.
- Full Text:
- Date Issued: 2011
- Authors: Ndlela, Joshua Bongani
- Date: 2011
- Subjects: Community development -- South Africa -- Eastern Cape , AIDS (Disease) -- South Africa -- Eastern Cape , HIV infections -- Social aspects -- South Africa -- Eastern Cape , Organisational behavior , Health promotion -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9837 , http://hdl.handle.net/10948/1657 , Community development -- South Africa -- Eastern Cape , AIDS (Disease) -- South Africa -- Eastern Cape , HIV infections -- Social aspects -- South Africa -- Eastern Cape , Organisational behavior , Health promotion -- South Africa -- Eastern Cape
- Description: The general aim of the study was to explore and describe community development workers` perceptions of wellness at an HIV/AIDS organisation in Nelson Mandela Bay, South Africa. The population of 36 community development workers at the Nelson Mandela Bay office of this organisation participated in this study. The sampling technique employed can be described as a census as it involved sampling an entire finite population that included all community development workers in the organisation. These workers are predominantly Xhosa-speaking adults between the ages of 21 and 60 years, and include both males and females. Qualitative data were gathered by means of audio-recorded focus groups, utilising semi-structured interviews. Tesch`s method was used to analyse the data, while Guba`s guidelines were used to enhance the trustworthiness of the research. Focus group interviews with community development workers revealed seven common themes in the experience of working in the HIV/AIDS organisation: (a) participants’ understanding of wellness; (b) organisational factors that impact on wellness; (c) personal factors that impact on wellness; (d) family and community factors that impact on wellness; (e) participants’ wellness; (f) personal coping strategies; and (g) suggestions regarding organisational strategies to enhance employee wellness. It is envisaged that the research findings of this study will be used in future to direct interventions that will be beneficial for the short and long term planning for the wellness of the community development workers of the HIV/AIDS organisation and those around them. It was recommended that the organisation was to develop a workplace wellness programme, increase management support towards the staff wellness and to increase the staff capacity.
- Full Text:
- Date Issued: 2011
Community participation and food security in rural Zimbabwe: the case of Marange area in Mutare district
- Authors: Swikepi, Chiedzwa
- Date: 2011
- Subjects: Community development , Rural development projects -- Zimbabwe -- Citizen participation , Community development -- Zimbabwe -- Citizen participation , Rural development -- Zimbabwe , Food security -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M Soc Sc (Dev)
- Identifier: vital:11845 , http://hdl.handle.net/10353/d1007303 , Community development , Rural development projects -- Zimbabwe -- Citizen participation , Community development -- Zimbabwe -- Citizen participation , Rural development -- Zimbabwe , Food security -- Zimbabwe
- Description: The chief purpose of this study was to determine the role of the rural communities in the food security initiatives of the government in alleviating food shortages in the Marange communal area of Mutare district in Zimbabwe. The focus was on local community empowerment; ownership of food security initiatives by the communities; communities‟ independent analysis of needs and priorities; their involvement in designing food security programmes and the role of the government in linking with the communities. The data was gathered using a case study research design with the qualitative method being the main research approach. The primary data was obtained from focus group discussions held in three wards of Marange area and some in-depth interviews conducted with selected key informants. The findings indicate that the government designs food security strategies without considering the input of communities. The communities are introduced and expected to adopt these pre-conceived food security plans at the implementation stage. The results also show that poor community participation in the food security initiatives of the government, specifically during the initial stages, is a significant contributing factor to the continual shortages of food in the communal lands of Marange. It is the view of this study that unless community input in decision making at the planning and designing phases is given preference in the food security interventions of the government in rural Zimbabwe, food security will seldom be achieved. While the government has a significant role to play in food security measures, such interventions can make an important contribution if the use and development of community participation is made central to food shortage alleviation strategies. The principal conclusion of this study is that if food security is an intended ultimate goal in rural Zimbabwe, the communities must participate fully in the conceptualisation, planning, implementation, monitoring and evaluation of the government-initiated food security programmes.
- Full Text:
- Date Issued: 2011
- Authors: Swikepi, Chiedzwa
- Date: 2011
- Subjects: Community development , Rural development projects -- Zimbabwe -- Citizen participation , Community development -- Zimbabwe -- Citizen participation , Rural development -- Zimbabwe , Food security -- Zimbabwe
- Language: English
- Type: Thesis , Masters , M Soc Sc (Dev)
- Identifier: vital:11845 , http://hdl.handle.net/10353/d1007303 , Community development , Rural development projects -- Zimbabwe -- Citizen participation , Community development -- Zimbabwe -- Citizen participation , Rural development -- Zimbabwe , Food security -- Zimbabwe
- Description: The chief purpose of this study was to determine the role of the rural communities in the food security initiatives of the government in alleviating food shortages in the Marange communal area of Mutare district in Zimbabwe. The focus was on local community empowerment; ownership of food security initiatives by the communities; communities‟ independent analysis of needs and priorities; their involvement in designing food security programmes and the role of the government in linking with the communities. The data was gathered using a case study research design with the qualitative method being the main research approach. The primary data was obtained from focus group discussions held in three wards of Marange area and some in-depth interviews conducted with selected key informants. The findings indicate that the government designs food security strategies without considering the input of communities. The communities are introduced and expected to adopt these pre-conceived food security plans at the implementation stage. The results also show that poor community participation in the food security initiatives of the government, specifically during the initial stages, is a significant contributing factor to the continual shortages of food in the communal lands of Marange. It is the view of this study that unless community input in decision making at the planning and designing phases is given preference in the food security interventions of the government in rural Zimbabwe, food security will seldom be achieved. While the government has a significant role to play in food security measures, such interventions can make an important contribution if the use and development of community participation is made central to food shortage alleviation strategies. The principal conclusion of this study is that if food security is an intended ultimate goal in rural Zimbabwe, the communities must participate fully in the conceptualisation, planning, implementation, monitoring and evaluation of the government-initiated food security programmes.
- Full Text:
- Date Issued: 2011
Community participation in the implementation of the integrated development plan with reference to Inanda Township in the province of Kwa-Zulu Natal
- Authors: Ntuli, Leanett Fanyana
- Date: 2011
- Subjects: Local government--South Africa--Kwa-Zulu Natal--Inanda Townshi--Citizen participation , Citicen's advisory committees--South Africa--Kwa-Zulu Natal , Policy sciences , Rural development projects--South Africa--Kwa-Zulu Natal
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:8157 , http://hdl.handle.net/10948/1664 , Local government--South Africa--Kwa-Zulu Natal--Inanda Townshi--Citizen participation , Citicen's advisory committees--South Africa--Kwa-Zulu Natal , Policy sciences , Rural development projects--South Africa--Kwa-Zulu Natal
- Description: This study focuses on community participation in the implementation of the integrated development plan in Inanda Township in the Province of KwaZulu-Natal. The empirical part of the study was conducted on the Inanada, Ntuzuma, and KwaMashu area of the eThekwini Municipality. Ward committees are forums for community participation in municipalities. They enhance participatory democracy at the local sphere of government. The main function of ward committee members include advising the ward councilors on policy matters that affect their respective wards, identifying the needs and challenges that face the wards, and communicating information to communities residing in those wards. This study acknowledges the fact that, in terms of the policy framework, ward councillors are the chairpersons of their respective ward committees. They are there to assist the community to express its views and participate in the processes of policy-making. Ward committee members need to liaise with the community, bring issues to the ward committee meetings and take the concerns of the community to the relevant unit of the municipality. The role of ward committees is to facilitate service delivery in their communities. It also found that the efficacy of ward committees during the implementation phase of the IDP could be improved. Hence it recommends that the eThekwini Municipality must encourage local community members, ward committees and councillors to play their role during the implementation of the IDP.
- Full Text:
- Date Issued: 2011
- Authors: Ntuli, Leanett Fanyana
- Date: 2011
- Subjects: Local government--South Africa--Kwa-Zulu Natal--Inanda Townshi--Citizen participation , Citicen's advisory committees--South Africa--Kwa-Zulu Natal , Policy sciences , Rural development projects--South Africa--Kwa-Zulu Natal
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: vital:8157 , http://hdl.handle.net/10948/1664 , Local government--South Africa--Kwa-Zulu Natal--Inanda Townshi--Citizen participation , Citicen's advisory committees--South Africa--Kwa-Zulu Natal , Policy sciences , Rural development projects--South Africa--Kwa-Zulu Natal
- Description: This study focuses on community participation in the implementation of the integrated development plan in Inanda Township in the Province of KwaZulu-Natal. The empirical part of the study was conducted on the Inanada, Ntuzuma, and KwaMashu area of the eThekwini Municipality. Ward committees are forums for community participation in municipalities. They enhance participatory democracy at the local sphere of government. The main function of ward committee members include advising the ward councilors on policy matters that affect their respective wards, identifying the needs and challenges that face the wards, and communicating information to communities residing in those wards. This study acknowledges the fact that, in terms of the policy framework, ward councillors are the chairpersons of their respective ward committees. They are there to assist the community to express its views and participate in the processes of policy-making. Ward committee members need to liaise with the community, bring issues to the ward committee meetings and take the concerns of the community to the relevant unit of the municipality. The role of ward committees is to facilitate service delivery in their communities. It also found that the efficacy of ward committees during the implementation phase of the IDP could be improved. Hence it recommends that the eThekwini Municipality must encourage local community members, ward committees and councillors to play their role during the implementation of the IDP.
- Full Text:
- Date Issued: 2011
Community radio and museum outreach: a case study of community radio practices to inform the environment and sustainability programmes of Livingstone Museum
- Authors: Muloongo, Arthanitius Henry
- Date: 2011
- Subjects: Community radio -- Zambia Livingstone Museum Museum outreach programs -- Zambia Environmental education -- Zambia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1454 , http://hdl.handle.net/10962/d1003335
- Description: This is a qualitative study whose purpose was to investigate the community radio education practices and the museum outreach education activities with a view to understanding how a museum-radio partnership may be used to engage the Livingstone community in environment and sustainability learning. Environment and sustainability issues require a community approach in order to bring about sustained responses to environmental challenges. As such, the study worked with social learning ideas of engaging the community in environment and sustainability learning. The data was generated mainly from face-to-face semi-structured interviews involving three community radio stations, Radio Listener Clubs and museum experts. The data generated was then presented to a strategy workshop involving the Livingstone Museum and Radio Musi-otunya staff. Arising from this workshop, recommendations were made about the possibility of the museum working in partnership with the radio to engage the community in environmental education. The study has shown that much of the museum environmental education activities have been confined to exhibitions and lectures within the museum building, which has affected the number of people being serviced by the museum. These education activities are arranged such that museum expert-led knowledge is presented to the audience with minimal community engagement on the environmental learning content. The study has also shown that community radio programming provides opportunities for community-led social learning which the Livingstone Museum could make use of to engage the community in environmental learning. Community radio programming allows community participation through Radio Listener Clubs, in identification and presentation of local environmental issues. This makes it a suitable tool to address locally relevant environmental issues, by the local community. Environmental issues are different from one place to another. Therefore environmental education approaches that bring issues into the museum may fail to address the different environmental education issues in different community context. The study concludes by recommending that Livingstone Museum should explore the use of community radio so that their expert knowledge and that of the radio producers could be used to shape environmental education programmes to go beyond awareness-raising.
- Full Text:
- Date Issued: 2011
- Authors: Muloongo, Arthanitius Henry
- Date: 2011
- Subjects: Community radio -- Zambia Livingstone Museum Museum outreach programs -- Zambia Environmental education -- Zambia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1454 , http://hdl.handle.net/10962/d1003335
- Description: This is a qualitative study whose purpose was to investigate the community radio education practices and the museum outreach education activities with a view to understanding how a museum-radio partnership may be used to engage the Livingstone community in environment and sustainability learning. Environment and sustainability issues require a community approach in order to bring about sustained responses to environmental challenges. As such, the study worked with social learning ideas of engaging the community in environment and sustainability learning. The data was generated mainly from face-to-face semi-structured interviews involving three community radio stations, Radio Listener Clubs and museum experts. The data generated was then presented to a strategy workshop involving the Livingstone Museum and Radio Musi-otunya staff. Arising from this workshop, recommendations were made about the possibility of the museum working in partnership with the radio to engage the community in environmental education. The study has shown that much of the museum environmental education activities have been confined to exhibitions and lectures within the museum building, which has affected the number of people being serviced by the museum. These education activities are arranged such that museum expert-led knowledge is presented to the audience with minimal community engagement on the environmental learning content. The study has also shown that community radio programming provides opportunities for community-led social learning which the Livingstone Museum could make use of to engage the community in environmental learning. Community radio programming allows community participation through Radio Listener Clubs, in identification and presentation of local environmental issues. This makes it a suitable tool to address locally relevant environmental issues, by the local community. Environmental issues are different from one place to another. Therefore environmental education approaches that bring issues into the museum may fail to address the different environmental education issues in different community context. The study concludes by recommending that Livingstone Museum should explore the use of community radio so that their expert knowledge and that of the radio producers could be used to shape environmental education programmes to go beyond awareness-raising.
- Full Text:
- Date Issued: 2011
Comparative behavior of conjugates of tantalum phthalocyanines with gold nanoparticles or single walled carbon nanotubes towards bisphenol A electrocatalysis
- Chauke, Vongani P, Antunes, Edith M, Nyokong, Tebello
- Authors: Chauke, Vongani P , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247152 , vital:51551 , xlink:href="https://doi.org/10.1016/j.jelechem.2011.06.019"
- Description: The characterization of tantalum phthalocyanine conjugates with gold nanoparticles and single wall carbon nanotubes as well as their electrocatalytic oxidation of bisphenol A is hereby presented. The formation of the conjugates was confirmed by X-ray diffraction and transmission electron microscope techniques. Single walled carbon nanotube conjugates of TaPc complexes showed the best catalysis as well as less passivation for bisphenol A detection and significant recovery of ∼98% compared to gold nanoparticle conjugates.
- Full Text:
- Date Issued: 2011
- Authors: Chauke, Vongani P , Antunes, Edith M , Nyokong, Tebello
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/247152 , vital:51551 , xlink:href="https://doi.org/10.1016/j.jelechem.2011.06.019"
- Description: The characterization of tantalum phthalocyanine conjugates with gold nanoparticles and single wall carbon nanotubes as well as their electrocatalytic oxidation of bisphenol A is hereby presented. The formation of the conjugates was confirmed by X-ray diffraction and transmission electron microscope techniques. Single walled carbon nanotube conjugates of TaPc complexes showed the best catalysis as well as less passivation for bisphenol A detection and significant recovery of ∼98% compared to gold nanoparticle conjugates.
- Full Text:
- Date Issued: 2011
Comparative structural bioinformatics analysis of Bacillus amyloliquefaciens chemotaxis proteins within Bacillus subtilis group
- Yssel, Anna, Reva, Oleg, Tastan Bishop, Özlem
- Authors: Yssel, Anna , Reva, Oleg , Tastan Bishop, Özlem
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123966 , vital:35521 , https://doi.10.1007/s00253-011-3582-y
- Description: Chemotaxis is a process in which bacteria sense their chemical environment and move towards more favorable conditions. Since plant colonization by bacteria is a multifaceted process which requires a response to the complex chemical environment, a finely tuned and sensitive chemotaxis system is needed. Members of the Bacillus subtilis group including Bacillus amyloliquefaciens are industrially important, for example, as bio-pesticides. The group exhibits plant growth-promoting characteristics, with different specificity towards certain host plants. Therefore, we hypothesize that while the principal molecular mechanisms of bacterial chemotaxis may be conserved, the bacterial chemotaxis system may need an evolutionary tweaking to adapt it to specific requirements, particularly in the process of evolution of free-living soil organisms, towards plant colonization behaviour. To date, almost nothing is known about what parts of the chemotaxis proteins are subjected to positive amino acid substitutions, involved in adjusting the chemotaxis system of bacteria during speciation. In this novel study, positively selected and purified sites of chemotaxis proteins were calculated, and these residues were mapped onto homology models that were built for the chemotaxis proteins, in an attempt to understand the spatial evolution of the chemotaxis proteins. Various positively selected amino acids were identified in semi-conserved regions of the proteins away from the known active sites.
- Full Text:
- Date Issued: 2011
- Authors: Yssel, Anna , Reva, Oleg , Tastan Bishop, Özlem
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/123966 , vital:35521 , https://doi.10.1007/s00253-011-3582-y
- Description: Chemotaxis is a process in which bacteria sense their chemical environment and move towards more favorable conditions. Since plant colonization by bacteria is a multifaceted process which requires a response to the complex chemical environment, a finely tuned and sensitive chemotaxis system is needed. Members of the Bacillus subtilis group including Bacillus amyloliquefaciens are industrially important, for example, as bio-pesticides. The group exhibits plant growth-promoting characteristics, with different specificity towards certain host plants. Therefore, we hypothesize that while the principal molecular mechanisms of bacterial chemotaxis may be conserved, the bacterial chemotaxis system may need an evolutionary tweaking to adapt it to specific requirements, particularly in the process of evolution of free-living soil organisms, towards plant colonization behaviour. To date, almost nothing is known about what parts of the chemotaxis proteins are subjected to positive amino acid substitutions, involved in adjusting the chemotaxis system of bacteria during speciation. In this novel study, positively selected and purified sites of chemotaxis proteins were calculated, and these residues were mapped onto homology models that were built for the chemotaxis proteins, in an attempt to understand the spatial evolution of the chemotaxis proteins. Various positively selected amino acids were identified in semi-conserved regions of the proteins away from the known active sites.
- Full Text:
- Date Issued: 2011
Comparative study of the feeding damage caused by the South African biotypes of the Russian wheat aphid (Diuraphis noxia Kurdjumov) on resistant and non-resistant lines of barley (Hordeum vulgare L.)
- Authors: Jimoh, Mahboob Adekilekun
- Date: 2011
- Subjects: Aphids Russian wheat aphid -- Research -- South Africa Barley -- Diseases and pests -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4201 , http://hdl.handle.net/10962/d1003770
- Description: Cereal crop productivity is hampered when these plants are infested by phloem feeding aphids. A great deal of research has been carried out with the direct aim of a clearer understanding of the mechanism involved in the interaction between aphids and their host plants. Research has directly or indirectly been geared towards enhanced plant productivity and achieving sustainable agriculture. Barley (Hordeum vulgare L.) is an important small grain crop in South Africa, whose crop performance is negatively affected by fluctuations in weather patterns as well as by agricultural pests. One of the insect pests infesting barley is the Russian wheat aphid, Diuraphis noxia Kurdjumov (RWA), of which the two South African biotypes, codenamed RWASA1 and RWASA2, were studied in this thesis. During dry spells, RWA infestation becomes a more serious threat to barley productivity. Resistant plants have been used to combat RWA infestation of small grains. In South Africa, 27 RWA-resistant wheat cultivars are currently used in commercial cultivation, but no resistant barley lines have, unfortunately, been developed, in spite of this grain’s significant economic importance. This informed the study in this thesis, and this interest particularly focussed on three RWA-resistant lines developed by the USDA, testing their performance against South African RWA biotypes, for possible adaptation to South Africa. The aim was thus to examine the plant-aphid interactions, aphid breeding rates, plant damage and sustainability, evidence of resistance or tolerance and finally potential performance under elevated CO2 (a very real climate change threat). Two major avenues of research were undertaken. The first aspect involved examination of structural and functional damage caused by RWASA1 and RWASA2 on the three resistant and a non-resistant line. Aphid population growth and damage symptoms (chlorosis and leaf roll) of infestation by these aphid biotypes were evaluated. This was followed by a structural and functional approach in which the effects of feeding on the transport systems (phloem and xylem) of barley were investigated. Fluorescence microscopy techniques (using aniline blue fluorochrome, a specific stain for callose and 5,6-CFDA, a phloem-mobile probe) were applied to investigate the feeding-related damage caused by the aphids, through an examination of wound callose formation and related to this, the resultant reduction in phloem transport capacity. Transmission electron microscopy (TEM) techniques provided evidence of the extent of the feeding-related cell damage. The second aspect involved a study of the effect of changing CO2 concentrations ([CO2]) on the resistant and susceptible barley cultivars to feeding by the two RWA biotypes. Leaves of plants grown at ambient and two elevated levels of [CO2] were analysed to investigate the effect of changing [CO2] on biomass, leaf nitrogen content and C:N ratio of control (uninfested) and infested plants. The population growth studies showed that the populations of the two RWA biotypes as well as bird cherry-oat aphid (BCA, Rhopalosiphum padi L.) increased substantially on the four barley lines. BCA was included here, as it had been the subject of several previous studies. RWASA2 bred faster than RWASA1 on all lines. The breeding rates of the two RWA biotypes were both suppressed and at near-equivalent levels on the three resistant lines, compared to the non-resistant PUMA. This suggests that the resistant lines possessed an antibiosis resistance mechanism against the feeding aphids. Feeding by the aphids manifested in morphological damage symptoms of chlorosis and leaf roll. The two biotypes inflicted severe chlorosis and leaf roll on the non-resistant PUMA. In the resistant plants, leaf rolling was more severe because of RWASA2 feeding compared to RWASA1 feeding. In contrast, chlorosis symptoms were more severe during RWASA1 feeding than was the case with RWASA2 feeding. Investigation of the effect of aphid feeding on the plants showed that callose was deposited within 24h and that this increased with longer feeding exposure. Wound callose distribution is more extensive in the non-resistant PUMA than in the resistant plants. RWASA2 feeding on the resistant lines caused deposition of more callose than was evident with RWASA1 feeding. During long-term feeding, it was evident that variation in the intensity and amount of wound callose was visible in the longitudinal and transverse veins of the resistant plants. Of the three STARS plants, STARS-9301B had the least callose. Interestingly, wound callose occurred in both resistant and non-resistant plants, in sharp contrast to what has been reported on resistant wheat cultivars that were developed in South Africa. The relative reduction in the wound callose deposited in the resistant line, when compared to the non-resistant lines, suggests the presence of a mechanism in the resistant lines, which may prevent excessive callose formation. Alternatively, the mechanism may stimulate callose breakdown. RWASA2 feeding on the resistant lines deposited more wound callose than RWASA1 feeding. This evidence supports the hypothesis that RWASA2 is a resistance breaking and more aggressive feeder than RWASA1 is; and further underscores the urgent need for development of RWA-resistant barley cultivars. The ultrastructural investigation of the feeding damage showed that the two biotypes caused extensive vascular damage in non-resistant plants. There was extensive and severe cell disruption and often obliteration of cell structure of the vascular parenchyma, xylem and phloem elements. In sharp contrast, among the resistant plants, feeding-related cell damage appeared to be substantially reduced compared to the non-resistant PUMA. Low frequency of damaged cells indicated that majority of the cell components of the vascular tissues were intact and presumed functional. There was evidence of salivary material lining the secondary walls of the vascular tissue, which resulted in severe damage. Within xylem vessels, saliva material impregnated half-bordered pit pairs between the vessels and adjacent xylem parenchyma. This is believed to prevent solute exchange through this interface, thereby inducing leaf stress and vi leaf roll. A notable finding is that RWASA2 effectively induced more cell damage to vascular tissues in the resistant lines than did RWASA1. In general the experimental evidence (see Chapter 5) suggests that the resistant lines are possibly more tolerant (or able to cope with) to RWA feeding. Evidence for this is the reduction of wound callose and at the TEM level, a comparatively less obvious cell damage in the resistant lines, which suggests that they possess antibiosis and tolerance capacity. The apparent reduction of feeding-related cell damage from the TEM study confirmed the disruptive action of the feeding aphids in experiments using the phloem-mobile probe, 5,6-CF. Results showed that feeding by RWASA1 and RWASA2 reducedthe transport functionality of the phloem in all cases, but that RWASA2 feeding caused a more obvious reduction in the rate and distance that 5,6-carboxyfluorescein was transported, than did RWASA1. Investigation of the effect of changing [CO2] on the barley cultivars showed that in the absence of aphids and under elevated CO2 conditions, the plants grew more vigorously. In this series of experiments, the infested plants suffered significant reduction in biomass under ambient (as was expected) and under the two elevated CO2 regimes. Biomass loss was greater at elevated CO2 than under ambient [CO2]. The infested nonresistant PUMA plants showed a more significant biomass loss than did the resistant cultivars. Clearly, the benefits derived from elevated CO2 enrichment was thus redirected to the now-advantaged aphids. Uninfested vii plants showed an increase in leaf nitrogen under the experimental conditions. However, feeding aphids depleted leaf nitrogen content and this was more apparent on plants exposed to RWASA2 than was the case with RWASA1. The end result of this was that C:N ratio of infested plants were higher than uninfested plants. Clearly, the faster breeding rates of the aphids at elevated CO2 caused depletion of N and a resultant deficiency exacerbated chlorosis as well as leaf rolling due to the higher aphid population density under elevated CO2 than at ambient. By 28 days after infestation (DAI), majority of the plants exposed to enriched CO2 treatments had died. A major finding here was thus that although this study demonstrated that elevated CO2 resulted in an increase in biomass, this was detrimentally offset in plants infested by the aphids, with a decline in biomass and loss of functionality leading to plant death at 28DAI. The overriding conclusion from this study is a clear signal that the twin effects of CO2 enrichment (a feature of current climate change) and aphid infestations may precipitate potential grain shortages. A disastrous food security threat looms.
- Full Text:
- Date Issued: 2011
- Authors: Jimoh, Mahboob Adekilekun
- Date: 2011
- Subjects: Aphids Russian wheat aphid -- Research -- South Africa Barley -- Diseases and pests -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4201 , http://hdl.handle.net/10962/d1003770
- Description: Cereal crop productivity is hampered when these plants are infested by phloem feeding aphids. A great deal of research has been carried out with the direct aim of a clearer understanding of the mechanism involved in the interaction between aphids and their host plants. Research has directly or indirectly been geared towards enhanced plant productivity and achieving sustainable agriculture. Barley (Hordeum vulgare L.) is an important small grain crop in South Africa, whose crop performance is negatively affected by fluctuations in weather patterns as well as by agricultural pests. One of the insect pests infesting barley is the Russian wheat aphid, Diuraphis noxia Kurdjumov (RWA), of which the two South African biotypes, codenamed RWASA1 and RWASA2, were studied in this thesis. During dry spells, RWA infestation becomes a more serious threat to barley productivity. Resistant plants have been used to combat RWA infestation of small grains. In South Africa, 27 RWA-resistant wheat cultivars are currently used in commercial cultivation, but no resistant barley lines have, unfortunately, been developed, in spite of this grain’s significant economic importance. This informed the study in this thesis, and this interest particularly focussed on three RWA-resistant lines developed by the USDA, testing their performance against South African RWA biotypes, for possible adaptation to South Africa. The aim was thus to examine the plant-aphid interactions, aphid breeding rates, plant damage and sustainability, evidence of resistance or tolerance and finally potential performance under elevated CO2 (a very real climate change threat). Two major avenues of research were undertaken. The first aspect involved examination of structural and functional damage caused by RWASA1 and RWASA2 on the three resistant and a non-resistant line. Aphid population growth and damage symptoms (chlorosis and leaf roll) of infestation by these aphid biotypes were evaluated. This was followed by a structural and functional approach in which the effects of feeding on the transport systems (phloem and xylem) of barley were investigated. Fluorescence microscopy techniques (using aniline blue fluorochrome, a specific stain for callose and 5,6-CFDA, a phloem-mobile probe) were applied to investigate the feeding-related damage caused by the aphids, through an examination of wound callose formation and related to this, the resultant reduction in phloem transport capacity. Transmission electron microscopy (TEM) techniques provided evidence of the extent of the feeding-related cell damage. The second aspect involved a study of the effect of changing CO2 concentrations ([CO2]) on the resistant and susceptible barley cultivars to feeding by the two RWA biotypes. Leaves of plants grown at ambient and two elevated levels of [CO2] were analysed to investigate the effect of changing [CO2] on biomass, leaf nitrogen content and C:N ratio of control (uninfested) and infested plants. The population growth studies showed that the populations of the two RWA biotypes as well as bird cherry-oat aphid (BCA, Rhopalosiphum padi L.) increased substantially on the four barley lines. BCA was included here, as it had been the subject of several previous studies. RWASA2 bred faster than RWASA1 on all lines. The breeding rates of the two RWA biotypes were both suppressed and at near-equivalent levels on the three resistant lines, compared to the non-resistant PUMA. This suggests that the resistant lines possessed an antibiosis resistance mechanism against the feeding aphids. Feeding by the aphids manifested in morphological damage symptoms of chlorosis and leaf roll. The two biotypes inflicted severe chlorosis and leaf roll on the non-resistant PUMA. In the resistant plants, leaf rolling was more severe because of RWASA2 feeding compared to RWASA1 feeding. In contrast, chlorosis symptoms were more severe during RWASA1 feeding than was the case with RWASA2 feeding. Investigation of the effect of aphid feeding on the plants showed that callose was deposited within 24h and that this increased with longer feeding exposure. Wound callose distribution is more extensive in the non-resistant PUMA than in the resistant plants. RWASA2 feeding on the resistant lines caused deposition of more callose than was evident with RWASA1 feeding. During long-term feeding, it was evident that variation in the intensity and amount of wound callose was visible in the longitudinal and transverse veins of the resistant plants. Of the three STARS plants, STARS-9301B had the least callose. Interestingly, wound callose occurred in both resistant and non-resistant plants, in sharp contrast to what has been reported on resistant wheat cultivars that were developed in South Africa. The relative reduction in the wound callose deposited in the resistant line, when compared to the non-resistant lines, suggests the presence of a mechanism in the resistant lines, which may prevent excessive callose formation. Alternatively, the mechanism may stimulate callose breakdown. RWASA2 feeding on the resistant lines deposited more wound callose than RWASA1 feeding. This evidence supports the hypothesis that RWASA2 is a resistance breaking and more aggressive feeder than RWASA1 is; and further underscores the urgent need for development of RWA-resistant barley cultivars. The ultrastructural investigation of the feeding damage showed that the two biotypes caused extensive vascular damage in non-resistant plants. There was extensive and severe cell disruption and often obliteration of cell structure of the vascular parenchyma, xylem and phloem elements. In sharp contrast, among the resistant plants, feeding-related cell damage appeared to be substantially reduced compared to the non-resistant PUMA. Low frequency of damaged cells indicated that majority of the cell components of the vascular tissues were intact and presumed functional. There was evidence of salivary material lining the secondary walls of the vascular tissue, which resulted in severe damage. Within xylem vessels, saliva material impregnated half-bordered pit pairs between the vessels and adjacent xylem parenchyma. This is believed to prevent solute exchange through this interface, thereby inducing leaf stress and vi leaf roll. A notable finding is that RWASA2 effectively induced more cell damage to vascular tissues in the resistant lines than did RWASA1. In general the experimental evidence (see Chapter 5) suggests that the resistant lines are possibly more tolerant (or able to cope with) to RWA feeding. Evidence for this is the reduction of wound callose and at the TEM level, a comparatively less obvious cell damage in the resistant lines, which suggests that they possess antibiosis and tolerance capacity. The apparent reduction of feeding-related cell damage from the TEM study confirmed the disruptive action of the feeding aphids in experiments using the phloem-mobile probe, 5,6-CF. Results showed that feeding by RWASA1 and RWASA2 reducedthe transport functionality of the phloem in all cases, but that RWASA2 feeding caused a more obvious reduction in the rate and distance that 5,6-carboxyfluorescein was transported, than did RWASA1. Investigation of the effect of changing [CO2] on the barley cultivars showed that in the absence of aphids and under elevated CO2 conditions, the plants grew more vigorously. In this series of experiments, the infested plants suffered significant reduction in biomass under ambient (as was expected) and under the two elevated CO2 regimes. Biomass loss was greater at elevated CO2 than under ambient [CO2]. The infested nonresistant PUMA plants showed a more significant biomass loss than did the resistant cultivars. Clearly, the benefits derived from elevated CO2 enrichment was thus redirected to the now-advantaged aphids. Uninfested vii plants showed an increase in leaf nitrogen under the experimental conditions. However, feeding aphids depleted leaf nitrogen content and this was more apparent on plants exposed to RWASA2 than was the case with RWASA1. The end result of this was that C:N ratio of infested plants were higher than uninfested plants. Clearly, the faster breeding rates of the aphids at elevated CO2 caused depletion of N and a resultant deficiency exacerbated chlorosis as well as leaf rolling due to the higher aphid population density under elevated CO2 than at ambient. By 28 days after infestation (DAI), majority of the plants exposed to enriched CO2 treatments had died. A major finding here was thus that although this study demonstrated that elevated CO2 resulted in an increase in biomass, this was detrimentally offset in plants infested by the aphids, with a decline in biomass and loss of functionality leading to plant death at 28DAI. The overriding conclusion from this study is a clear signal that the twin effects of CO2 enrichment (a feature of current climate change) and aphid infestations may precipitate potential grain shortages. A disastrous food security threat looms.
- Full Text:
- Date Issued: 2011
Comparison between Endothelin, Nitric Oxide and their Association to Blood Pressure and Body Composition in HIV Patients, in Mthatha
- Authors: Zono, Sinethemba
- Date: 2011
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3550 , vital:43627
- Description: The motivation for this study is that Health Resource Centres of the Eastern Cape ought to provide access to high quality, relevant and appropriate information that is evidence-based and responsive to the needs of health professionals thereby assisting health professionals accomplish their tasks. In order to provide access to quality information, the Health Resource Centres are expected to provide information services within an acceptable framework of service standards. This study seeks to explore the implementation of standards in the Health Resource Centres of the Eastern Cape. The study was carried out in two phases namely a literature review and a survey. The study used the quantitative method of collecting data by means of a cross-sectional survey. A self administered questionnaire was used to collect data. The questionnaire was piloted in the Queenstown Health Resource Centre, after which appropriate changes were made before the commencement of data collection. The study was conducted in the three other Health Resource Centres of the Eastern Cape, namely Umtata Health Resource Centre, East London Health Resource Centre and Port Elizabeth Health Resource Centre. Health Resource Centre managers completed the questionnaires. The overall findings of this study show that the three Health Resource Centres uphold service standards. The results show that the Health Resource Centres were compliant with the service standards relating to both services and management areas. The Health Resource Centres were more compliant with standards relating to service areas than they were to standards relating to management areas. The results of the study furthermore demonstrate that the Umtata Health Resource Centre was most compliant regarding service areas (86,20%) compared to the East London Health Resource Centre (82,75%) and the Port Elizabeth Health Resource Centre (72,41%). In regard to management areas, the results show that the Umtata Health Resource Centre and East London Health Resource were more compliant than the Port Elizabeth Health Resource Centre. However certain aspects of their service such as availability of space, health and safety, staff performance and development, quality leadership and design and financial management need further attention. The study suggests that further research is required to objectively verify implementation of standards, to solicit health professionals’ opinions and experiences about the services provided by these Health Resource Centres and to find out if there is any connection between the quality of services provided and the quality of patient care. , Thesis (MSc) -- Faculty of Health Sciences, 2015
- Full Text:
- Date Issued: 2011
- Authors: Zono, Sinethemba
- Date: 2011
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/11260/3550 , vital:43627
- Description: The motivation for this study is that Health Resource Centres of the Eastern Cape ought to provide access to high quality, relevant and appropriate information that is evidence-based and responsive to the needs of health professionals thereby assisting health professionals accomplish their tasks. In order to provide access to quality information, the Health Resource Centres are expected to provide information services within an acceptable framework of service standards. This study seeks to explore the implementation of standards in the Health Resource Centres of the Eastern Cape. The study was carried out in two phases namely a literature review and a survey. The study used the quantitative method of collecting data by means of a cross-sectional survey. A self administered questionnaire was used to collect data. The questionnaire was piloted in the Queenstown Health Resource Centre, after which appropriate changes were made before the commencement of data collection. The study was conducted in the three other Health Resource Centres of the Eastern Cape, namely Umtata Health Resource Centre, East London Health Resource Centre and Port Elizabeth Health Resource Centre. Health Resource Centre managers completed the questionnaires. The overall findings of this study show that the three Health Resource Centres uphold service standards. The results show that the Health Resource Centres were compliant with the service standards relating to both services and management areas. The Health Resource Centres were more compliant with standards relating to service areas than they were to standards relating to management areas. The results of the study furthermore demonstrate that the Umtata Health Resource Centre was most compliant regarding service areas (86,20%) compared to the East London Health Resource Centre (82,75%) and the Port Elizabeth Health Resource Centre (72,41%). In regard to management areas, the results show that the Umtata Health Resource Centre and East London Health Resource were more compliant than the Port Elizabeth Health Resource Centre. However certain aspects of their service such as availability of space, health and safety, staff performance and development, quality leadership and design and financial management need further attention. The study suggests that further research is required to objectively verify implementation of standards, to solicit health professionals’ opinions and experiences about the services provided by these Health Resource Centres and to find out if there is any connection between the quality of services provided and the quality of patient care. , Thesis (MSc) -- Faculty of Health Sciences, 2015
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- Date Issued: 2011