Physical activity in the lives of two generations of black professional women in the Nelson Mandela Metropolitan Municipality
- Authors: Walter, Cheryl Michelle
- Date: 2008
- Subjects: Physical education for women , Physical fitness for women , Women -- Health and hygiene
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10089 , http://hdl.handle.net/10948/664 , Physical education for women , Physical fitness for women , Women -- Health and hygiene
- Description: The association between physical inactivity, adverse health and hypokinetic diseases has been widely researched. There is an increased risk of being overweight, and of developing certain chronic diseases and suffering premature death associated with physical inactivity (Young, Miller, Wilder, Yanek & Becker, 1998). Recent surveys and studies have revealed that the majority of the South African population has moved extensively along the epidemiological transition towards a disease profile related to Western lifestyle, where deaths due to chronic diseases of lifestyle is a great cause for concern (Steyn, 2006). Black women, in particular, have been identified as a high risk group with the highest levels of inactivity and the highest levels of overweight and obesity in the country (SADHS, 1998; WHO, 2005). Although there is a growing body of knowledge and research on physical activity in general, there is still a lack of data on the determinants and barriers to participation in physical activity (Lambert & Kolbe-Alexander, 2006). Cultural patterns and economic, political and ideological orders affect the participation of women in sport (Hargreaves, 1994:5). Black women in South Africa have been disadvantaged by the past government’s policy of apartheid, and have also been marginalized and oppressed in their own patriarchal societies. The first democratically elected government in 1994, however, committed itself to gender equality and women’s emancipation, with constitutional guarantees on equality and an affirmative action policy to address gender inequalities. In order to evaluate the extent of the beneficial impact of these political changes in women’s lives, this study proposed to investigate physical activity patterns in the lives of two generations of black professional women (teachers, nurses, social workers and public managers) from the Nelson Mandela Metropolitan Municipality. The objectives that guided the research were: • To describe and compare the physical activity patterns and health status of two generations of black women through questionnaires, physical activity records and mechanical devices. • To explore and describe the psychosocial context and socio-cultural influences on physical activity in the lives of the participants. xi • To explore and describe the participants’ perceptions and attitudes, motivations and constraints relating to physical activity. • To use the research findings to compile guidelines to promote physical activity participation among black women. A mixed method approach using both quantitative and qualitative methods was selected to achieve an holistic understanding of physical activity in the lives of black South African women. The older generation (OG) of professional women was comprised of community teachers, nurses, social workers and public managers (n=111, aged 35 to 45 years, mean age = 39.87 years). These women, through their occupations, were in constant contact with the community and could be regarded as role models who influence community lifestyle, attitudes and behaviour. The younger generation (YG) (n=69, aged 18 to 21 years, mean age = 20.12 years) was comprised of teaching, nursing, social work and public management students in the Nelson Mandela Metropolitan Municipality. The objective of the quantitative section of the study was to provide baseline information on the physical activity patterns and health status of these two generations of black professional women. Physical activity and health questionnaires were administered and the ActiGraph GT1 accelerometer was used to provide an objective measure of energy expenditure. The objective of the qualitative data collection was to explore and describe the psychosocial context and socio-cultural influences on physical activity in the lives of the participants, and to investigate their attitudes to and perceptions of physical activity, and their motivations and constraints related to it. In-depth qualitative interviews were held with the participants who wore the ActiGraph, and a group of 47 were interviewed (sample size determined by data saturation from the interviews). An explorative-descriptive research design was used in the study. The sampling method was purposive and criterion-based. The younger generation of students were mostly selected from the various campuses of the Nelson Mandela Metropolitan University, while additional student nurses were recruited from the Lilitha Nursing College in the Nelson Mandela Metropolitan Municipality. The older generation of professionals were recruited from schools and clinics in the areas of New Brighton, Kwa-Zakhele, Zwide, Motherwell and Kwa-Nobuhle (all historically black areas), the Eastern Cape Department of Social Development, non-government organizations and the Nelson Mandela Metropolitan Municipality. xii The quantitative data were analysed by means of descriptive and inferential statistics. The qualitative data was analysed according to the steps described in Creswell (2003). The results of the quantitative data indicated that prevalence of overweight and obesity among both the YG and OG was high. The mean BMI for the YG and OG were 24.71 kg/m2 and 31.27 kg/m2, respectively, with 41% of the YG and 86% of the OG falling into the overweight/obesity category. BMI was significantly greater (p<.05) for the OG than for the YG. In addition, both the OG and YG had satisfactory scores for the health-related behaviour measures (the Belloc and Breslow Lifestyle Index and the HPLP). All the physical activity measurements (the FIT Index of Kasari, the GPAQ and the ActiGraph data) confirmed that both the YG and OG were not sufficiently physically active. They did not meet the Centre of Disease Control (CDC) and American College of Sports Medicine (ACSM) recommendation of engaging in at least 30 minutes of moderate-intensity physical activity on most, or preferably all, days of the week. The YG were significantly more active than the OG in all the physical activity measuring instruments. They were still, however, not reaching the health enhancing physical activity (HEPA) level (≥7 days of any combination of moderate and vigorous activity, ≥ 3000 METmins/week). Pearson Product Moment correlations were calculated to determine the relationship among the various measurements of physical activity o the one hand and the relationship between the measurements of physical activity and the health-related behaviour measurements on the other hand. The correlational analyses highlighted a good cross-validation of the various measures of physical activity. There was a significant correlation between the measures of leisure time physical activity, that is the FIT Index, and the leisure domain of the GPAQ. There was also a significant relationship in the area of walking or steps taken, that is the ActiGraph steps and the GPAQ transport domain. There was also a significant relationship between the overall measures of physical activity, that is the GPAQ total score, and the ActiGraph calories. The correlations between the various physical activity and health related behaviour measures revealed that only the leisure related physical activity measurements, that is, the FIT index and the GPAQ leisure domain, had a significant correlation with the two health related behaviour measures, namely the Belloc and Breslow Lifestyle Index and the HPLP, respectively. xiii The results from the qualitative data revealed that both the OG and YG had positive attitudes towards physical activity participation (displayed by their awareness of the many benefits, their expressed intention to start exercising, the encouragement given to their children in relation to physical activity participation), even though the majority of them were not active on a regular basis. Participants recognized the educational, recreational and developmental importance of being physically active, a shift in attitude from their own upbringing and lifestyles. Regardless of how firmly people may believe that physical activity is beneficial to their health, there are many barriers, whether real or perceived, that represent significant potential obstructions to the adoption, maintenance, or resumption of participation in physical activity (Booth et al., 1997). Three sub-themes were identified in relation to the barriers to physical activity participation, namely personal factors, environmental factors and socio-cultural factors. The personal factors included time constraints, stress and tiredness, lack of motivation, negative school experiences, negative associations with exercise and financial constraints. The environmental factors included residential areas, availability of recreation and sports facilities, and safety. The socio-cultural factors were lack of social support, exercise “not being a part of African culture”, traditional roles of males and females, dress code, exercise associated with the young, exercise associated with undesirable weight loss and negative comments by the community. On the basis of research findings, guidelines were drawn up for the promotion of physical activity participation among black women.
- Full Text:
- Date Issued: 2008
- Authors: Walter, Cheryl Michelle
- Date: 2008
- Subjects: Physical education for women , Physical fitness for women , Women -- Health and hygiene
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10089 , http://hdl.handle.net/10948/664 , Physical education for women , Physical fitness for women , Women -- Health and hygiene
- Description: The association between physical inactivity, adverse health and hypokinetic diseases has been widely researched. There is an increased risk of being overweight, and of developing certain chronic diseases and suffering premature death associated with physical inactivity (Young, Miller, Wilder, Yanek & Becker, 1998). Recent surveys and studies have revealed that the majority of the South African population has moved extensively along the epidemiological transition towards a disease profile related to Western lifestyle, where deaths due to chronic diseases of lifestyle is a great cause for concern (Steyn, 2006). Black women, in particular, have been identified as a high risk group with the highest levels of inactivity and the highest levels of overweight and obesity in the country (SADHS, 1998; WHO, 2005). Although there is a growing body of knowledge and research on physical activity in general, there is still a lack of data on the determinants and barriers to participation in physical activity (Lambert & Kolbe-Alexander, 2006). Cultural patterns and economic, political and ideological orders affect the participation of women in sport (Hargreaves, 1994:5). Black women in South Africa have been disadvantaged by the past government’s policy of apartheid, and have also been marginalized and oppressed in their own patriarchal societies. The first democratically elected government in 1994, however, committed itself to gender equality and women’s emancipation, with constitutional guarantees on equality and an affirmative action policy to address gender inequalities. In order to evaluate the extent of the beneficial impact of these political changes in women’s lives, this study proposed to investigate physical activity patterns in the lives of two generations of black professional women (teachers, nurses, social workers and public managers) from the Nelson Mandela Metropolitan Municipality. The objectives that guided the research were: • To describe and compare the physical activity patterns and health status of two generations of black women through questionnaires, physical activity records and mechanical devices. • To explore and describe the psychosocial context and socio-cultural influences on physical activity in the lives of the participants. xi • To explore and describe the participants’ perceptions and attitudes, motivations and constraints relating to physical activity. • To use the research findings to compile guidelines to promote physical activity participation among black women. A mixed method approach using both quantitative and qualitative methods was selected to achieve an holistic understanding of physical activity in the lives of black South African women. The older generation (OG) of professional women was comprised of community teachers, nurses, social workers and public managers (n=111, aged 35 to 45 years, mean age = 39.87 years). These women, through their occupations, were in constant contact with the community and could be regarded as role models who influence community lifestyle, attitudes and behaviour. The younger generation (YG) (n=69, aged 18 to 21 years, mean age = 20.12 years) was comprised of teaching, nursing, social work and public management students in the Nelson Mandela Metropolitan Municipality. The objective of the quantitative section of the study was to provide baseline information on the physical activity patterns and health status of these two generations of black professional women. Physical activity and health questionnaires were administered and the ActiGraph GT1 accelerometer was used to provide an objective measure of energy expenditure. The objective of the qualitative data collection was to explore and describe the psychosocial context and socio-cultural influences on physical activity in the lives of the participants, and to investigate their attitudes to and perceptions of physical activity, and their motivations and constraints related to it. In-depth qualitative interviews were held with the participants who wore the ActiGraph, and a group of 47 were interviewed (sample size determined by data saturation from the interviews). An explorative-descriptive research design was used in the study. The sampling method was purposive and criterion-based. The younger generation of students were mostly selected from the various campuses of the Nelson Mandela Metropolitan University, while additional student nurses were recruited from the Lilitha Nursing College in the Nelson Mandela Metropolitan Municipality. The older generation of professionals were recruited from schools and clinics in the areas of New Brighton, Kwa-Zakhele, Zwide, Motherwell and Kwa-Nobuhle (all historically black areas), the Eastern Cape Department of Social Development, non-government organizations and the Nelson Mandela Metropolitan Municipality. xii The quantitative data were analysed by means of descriptive and inferential statistics. The qualitative data was analysed according to the steps described in Creswell (2003). The results of the quantitative data indicated that prevalence of overweight and obesity among both the YG and OG was high. The mean BMI for the YG and OG were 24.71 kg/m2 and 31.27 kg/m2, respectively, with 41% of the YG and 86% of the OG falling into the overweight/obesity category. BMI was significantly greater (p<.05) for the OG than for the YG. In addition, both the OG and YG had satisfactory scores for the health-related behaviour measures (the Belloc and Breslow Lifestyle Index and the HPLP). All the physical activity measurements (the FIT Index of Kasari, the GPAQ and the ActiGraph data) confirmed that both the YG and OG were not sufficiently physically active. They did not meet the Centre of Disease Control (CDC) and American College of Sports Medicine (ACSM) recommendation of engaging in at least 30 minutes of moderate-intensity physical activity on most, or preferably all, days of the week. The YG were significantly more active than the OG in all the physical activity measuring instruments. They were still, however, not reaching the health enhancing physical activity (HEPA) level (≥7 days of any combination of moderate and vigorous activity, ≥ 3000 METmins/week). Pearson Product Moment correlations were calculated to determine the relationship among the various measurements of physical activity o the one hand and the relationship between the measurements of physical activity and the health-related behaviour measurements on the other hand. The correlational analyses highlighted a good cross-validation of the various measures of physical activity. There was a significant correlation between the measures of leisure time physical activity, that is the FIT Index, and the leisure domain of the GPAQ. There was also a significant relationship in the area of walking or steps taken, that is the ActiGraph steps and the GPAQ transport domain. There was also a significant relationship between the overall measures of physical activity, that is the GPAQ total score, and the ActiGraph calories. The correlations between the various physical activity and health related behaviour measures revealed that only the leisure related physical activity measurements, that is, the FIT index and the GPAQ leisure domain, had a significant correlation with the two health related behaviour measures, namely the Belloc and Breslow Lifestyle Index and the HPLP, respectively. xiii The results from the qualitative data revealed that both the OG and YG had positive attitudes towards physical activity participation (displayed by their awareness of the many benefits, their expressed intention to start exercising, the encouragement given to their children in relation to physical activity participation), even though the majority of them were not active on a regular basis. Participants recognized the educational, recreational and developmental importance of being physically active, a shift in attitude from their own upbringing and lifestyles. Regardless of how firmly people may believe that physical activity is beneficial to their health, there are many barriers, whether real or perceived, that represent significant potential obstructions to the adoption, maintenance, or resumption of participation in physical activity (Booth et al., 1997). Three sub-themes were identified in relation to the barriers to physical activity participation, namely personal factors, environmental factors and socio-cultural factors. The personal factors included time constraints, stress and tiredness, lack of motivation, negative school experiences, negative associations with exercise and financial constraints. The environmental factors included residential areas, availability of recreation and sports facilities, and safety. The socio-cultural factors were lack of social support, exercise “not being a part of African culture”, traditional roles of males and females, dress code, exercise associated with the young, exercise associated with undesirable weight loss and negative comments by the community. On the basis of research findings, guidelines were drawn up for the promotion of physical activity participation among black women.
- Full Text:
- Date Issued: 2008
Establishing experimental systems for studying the replication biology of Providence virus
- Authors: Walter, Cheryl Tracy
- Date: 2009
- Subjects: Insects -- Viruses Insects -- Diseases Insects -- Parasites Host-virus relationships RNA viruses DNA Insects as carriers of disease
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3928 , http://hdl.handle.net/10962/d1003987
- Description: Providence virus (PrV) is a member of the Tetraviridae, a family of small, positive sense, single-stranded RNA viruses, which characteristically infect the midgut tissue of heliothine larvae. PrV is the only known tetravirus that replicates in cultured insect cells. The virus comprises a monopartite genome resembling members of the genus Betatetravirus with the capsid precursor protein undergoing autoproteolytic cleavage at its C-terminus consistent with other tetravirus capsid precursor proteins. Analysis of viral cDNA predicted the presence of three potential overlapping gene products (from 5` to 3`): (1) p130, a protein of unrecognized nucleotide or amino acid homology with a 2A-like processing site at its N-terminus; (2) p104, the replicase ORF, which was found to be phylogenetically related to tombus-and umbraviruses replicases. The presence of a read-through stop signal in the p104 ORF was proposed to produce and amino terminal product with a predicted MW of 40 kDa (p40) and (3) the capsid protein precursor (81 kDa) which has two 2A-like processing sites at its N-terminus. Metabolic radiolabelling of viral translation products in persistently infected MG8 cells and in vitro translation of the individual ORFs were performed in order to analyse the expression of PrV gene products. p130 was translated with no evidence of 2A-like processing. Two products of 40 kDa and 104 kDa were translated from the p104 ORF, indicating that the read-through stop signal was likely to be functional. Finally, the capsid protein precursor ORF produced a major translation product of 68 kDa corresponding to the capsid protein precursor as well a peptide of 15 kDa that was attributed to the activity of the second 2A-like site at the N-terminus of the p81 ORF. The subcellular distribution of viral RNA (vRNA) and p40 in MG8 cells was investigated using immunofluorescence and biochemical fractionation. The results showed that p40/p104 and vRNA accumulated in polarized, punctate structures in some but not all MG8 cells and in some cases, co-localization was observed. This thesis concludes that PrV is a novel tetravirus with significant similarities plant carmolike viruses that should be re-classified at the family level.
- Full Text:
- Date Issued: 2009
- Authors: Walter, Cheryl Tracy
- Date: 2009
- Subjects: Insects -- Viruses Insects -- Diseases Insects -- Parasites Host-virus relationships RNA viruses DNA Insects as carriers of disease
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3928 , http://hdl.handle.net/10962/d1003987
- Description: Providence virus (PrV) is a member of the Tetraviridae, a family of small, positive sense, single-stranded RNA viruses, which characteristically infect the midgut tissue of heliothine larvae. PrV is the only known tetravirus that replicates in cultured insect cells. The virus comprises a monopartite genome resembling members of the genus Betatetravirus with the capsid precursor protein undergoing autoproteolytic cleavage at its C-terminus consistent with other tetravirus capsid precursor proteins. Analysis of viral cDNA predicted the presence of three potential overlapping gene products (from 5` to 3`): (1) p130, a protein of unrecognized nucleotide or amino acid homology with a 2A-like processing site at its N-terminus; (2) p104, the replicase ORF, which was found to be phylogenetically related to tombus-and umbraviruses replicases. The presence of a read-through stop signal in the p104 ORF was proposed to produce and amino terminal product with a predicted MW of 40 kDa (p40) and (3) the capsid protein precursor (81 kDa) which has two 2A-like processing sites at its N-terminus. Metabolic radiolabelling of viral translation products in persistently infected MG8 cells and in vitro translation of the individual ORFs were performed in order to analyse the expression of PrV gene products. p130 was translated with no evidence of 2A-like processing. Two products of 40 kDa and 104 kDa were translated from the p104 ORF, indicating that the read-through stop signal was likely to be functional. Finally, the capsid protein precursor ORF produced a major translation product of 68 kDa corresponding to the capsid protein precursor as well a peptide of 15 kDa that was attributed to the activity of the second 2A-like site at the N-terminus of the p81 ORF. The subcellular distribution of viral RNA (vRNA) and p40 in MG8 cells was investigated using immunofluorescence and biochemical fractionation. The results showed that p40/p104 and vRNA accumulated in polarized, punctate structures in some but not all MG8 cells and in some cases, co-localization was observed. This thesis concludes that PrV is a novel tetravirus with significant similarities plant carmolike viruses that should be re-classified at the family level.
- Full Text:
- Date Issued: 2009
The evolution of heteronomous host relationships in Aphelinidaa (Hymenoptera Chalcidoidea) with special reference to the biology of Coccophagus Bartletti Annecke and Insley
- Authors: Walter, Grenville Hugh
- Date: 1984
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5620 , http://hdl.handle.net/10962/d1003746
- Description: Résumé: Heteronomous host relationships are unique to parasitoids in about 8 aphelinid genera. Males have host relationships quite distinct from those of their females. Females of ALL species are primary endoparasitoids of homopterous hosts. Males, on the other hand, may be either primary ectoparasitoids of the same host species as their conspecific females, or they may be hyperparasitic upon parasitoids within Homoptera, and some are primary endoparasitoids of moth eggs. Species in these groups are termed DIPHAGOUS PARASITOIDS, HETERONOMOUS HYPERPARASITOIDS and HETEROTROPHIC PARASITOIDS, respectively. The selective advantages proposed to explain the evolution of these unusual host relationships are examined in this thesis. The biology of a diphagous parasitoid was examined in detail because diphagous parasitism is considered the most primitive of heteronomous host relationships. Diphagous parasitism is thought to have evolved during a period when ovipositing females continuously encountered large proportions of parasitised hosts. Larval competition may have generated the selection pressures that favoured male ectoparasitism. Ectoparasitoids are known to be superior in competition against other larvae, even older ones. A series of observations was carried out on the diphagous parasitoid, Coccophagus bartletti. Information was gathered on oviposition and host-feeding behaviour, daily activity patterns, and sex ratios in the laboratory and field. This enabled the design and interpretation of a series of observations on the responses of mated C. bartletti females to already-parasitised hosts. The results indicate that competition from other parasitoids probably played no role in the evolution of diphagous host relationships. Heteronomous hyperparasitoids, thought to have evolved from diphagous parasitoids, appear to be strong competitors because their males kill other parasitoids. However, an alternative hypothesis to the competition one, and based on the present study, is presented. Implications for the generally-held view, that competition is important in moulding species' characters, are discussed.
- Full Text:
- Date Issued: 1984
- Authors: Walter, Grenville Hugh
- Date: 1984
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5620 , http://hdl.handle.net/10962/d1003746
- Description: Résumé: Heteronomous host relationships are unique to parasitoids in about 8 aphelinid genera. Males have host relationships quite distinct from those of their females. Females of ALL species are primary endoparasitoids of homopterous hosts. Males, on the other hand, may be either primary ectoparasitoids of the same host species as their conspecific females, or they may be hyperparasitic upon parasitoids within Homoptera, and some are primary endoparasitoids of moth eggs. Species in these groups are termed DIPHAGOUS PARASITOIDS, HETERONOMOUS HYPERPARASITOIDS and HETEROTROPHIC PARASITOIDS, respectively. The selective advantages proposed to explain the evolution of these unusual host relationships are examined in this thesis. The biology of a diphagous parasitoid was examined in detail because diphagous parasitism is considered the most primitive of heteronomous host relationships. Diphagous parasitism is thought to have evolved during a period when ovipositing females continuously encountered large proportions of parasitised hosts. Larval competition may have generated the selection pressures that favoured male ectoparasitism. Ectoparasitoids are known to be superior in competition against other larvae, even older ones. A series of observations was carried out on the diphagous parasitoid, Coccophagus bartletti. Information was gathered on oviposition and host-feeding behaviour, daily activity patterns, and sex ratios in the laboratory and field. This enabled the design and interpretation of a series of observations on the responses of mated C. bartletti females to already-parasitised hosts. The results indicate that competition from other parasitoids probably played no role in the evolution of diphagous host relationships. Heteronomous hyperparasitoids, thought to have evolved from diphagous parasitoids, appear to be strong competitors because their males kill other parasitoids. However, an alternative hypothesis to the competition one, and based on the present study, is presented. Implications for the generally-held view, that competition is important in moulding species' characters, are discussed.
- Full Text:
- Date Issued: 1984
Wagon bridges of the Eastern Cape, c. 1840 – 1900: the contribution of engineering to infrastructural development
- Authors: Walters, Dennis Evelyn
- Date: 2018
- Subjects: Bridges Design and construction 19th century , Civil engineers South Africa Cape of Good Hope , Great Britain. Crown Agents' Office , Public works Great Britain Colonies , Wagon trains South Africa Cape of Good Hope
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63877 , vital:28500
- Description: This thesis examines an aspect of economic and technological history which has been little explored in South African history. It argues that the military subjugation and the economic development of the Cape Colony, and particularly of the Eastern Cape, were contingent upon good transportation. The geography of the country, which included relatively impassable mountains and numerous often flooded rivers, necessitated bridges as well as roads. Both were expensive. As a leader in industrial technology, Britain was well placed to extend bridge-building skills to its colonies. This thesis examines the processes by which a small and undeveloped colony strove to create an efficient technological infrastructure. As wagon traffic increased through progress, delays in crossing rivers became a hindrance leading to agitation for bridges. It will be shown that the construction of wagon bridges over the numerous rivers encountered in the Eastern Cape Colony was imperative for the initial free flow of military forces and for later commercial expansion as new towns were established. The eastward expansion was led by the military during the frontier wars followed by the Royal Engineers who built roads and bridges along the eastern frontier. The new Colonial Secretary John Montagu, who arrived in 1843, boosted the colonial finances by overhauling the administration. He established the Central Road Board, an organisation that would drive the building of mountain passes, roads and bridges. The Public Works Department succeeded the Central Road Board and with the financial intervention of the Crown Agents for the Colonies, carried on with an extensive programme of road and bridge building. From the 1870s wagon bridge building lagged behind the huge railway building enterprise in response to the opening up of the diamond and gold mines. The final quarter of the 19th century saw increased bridge building activity in the Eastern Cape with the construction of many iron lattice girder, stone masonry arch and timber trestle bridges. The surviving bridges remain as mute testimony to the skill and expertise of British engineers such as Lewis, Woodifield, Robinson, Fforde, Wakefield, Berkley, Grier, Newey, Westhoven and others.
- Full Text:
- Date Issued: 2018
- Authors: Walters, Dennis Evelyn
- Date: 2018
- Subjects: Bridges Design and construction 19th century , Civil engineers South Africa Cape of Good Hope , Great Britain. Crown Agents' Office , Public works Great Britain Colonies , Wagon trains South Africa Cape of Good Hope
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/63877 , vital:28500
- Description: This thesis examines an aspect of economic and technological history which has been little explored in South African history. It argues that the military subjugation and the economic development of the Cape Colony, and particularly of the Eastern Cape, were contingent upon good transportation. The geography of the country, which included relatively impassable mountains and numerous often flooded rivers, necessitated bridges as well as roads. Both were expensive. As a leader in industrial technology, Britain was well placed to extend bridge-building skills to its colonies. This thesis examines the processes by which a small and undeveloped colony strove to create an efficient technological infrastructure. As wagon traffic increased through progress, delays in crossing rivers became a hindrance leading to agitation for bridges. It will be shown that the construction of wagon bridges over the numerous rivers encountered in the Eastern Cape Colony was imperative for the initial free flow of military forces and for later commercial expansion as new towns were established. The eastward expansion was led by the military during the frontier wars followed by the Royal Engineers who built roads and bridges along the eastern frontier. The new Colonial Secretary John Montagu, who arrived in 1843, boosted the colonial finances by overhauling the administration. He established the Central Road Board, an organisation that would drive the building of mountain passes, roads and bridges. The Public Works Department succeeded the Central Road Board and with the financial intervention of the Crown Agents for the Colonies, carried on with an extensive programme of road and bridge building. From the 1870s wagon bridge building lagged behind the huge railway building enterprise in response to the opening up of the diamond and gold mines. The final quarter of the 19th century saw increased bridge building activity in the Eastern Cape with the construction of many iron lattice girder, stone masonry arch and timber trestle bridges. The surviving bridges remain as mute testimony to the skill and expertise of British engineers such as Lewis, Woodifield, Robinson, Fforde, Wakefield, Berkley, Grier, Newey, Westhoven and others.
- Full Text:
- Date Issued: 2018
Deliberately withheld meaning : aspects of narrative technique in four novels by William Faulkner
- Authors: Walters, Paul S
- Date: 1970
- Subjects: Faulkner, William, 1897-1962 -- Criticism and interpretation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2167 , http://hdl.handle.net/10962/d1001746
- Full Text:
- Date Issued: 1970
- Authors: Walters, Paul S
- Date: 1970
- Subjects: Faulkner, William, 1897-1962 -- Criticism and interpretation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2167 , http://hdl.handle.net/10962/d1001746
- Full Text:
- Date Issued: 1970
Mathematical requirements for first-year BCOM students at NMMU
- Authors: Walton, Marguerite
- Date: 2009
- Subjects: Business mathematics -- South Africa , Mathematics -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10502 , http://hdl.handle.net/10948/886 , Business mathematics -- South Africa , Mathematics -- Study and teaching (Higher) -- South Africa
- Description: These studies have focused on identifying the mathematical requirements of first-year BCom students at Nelson Mandela Metropolitan University. The research methodology used in this quantitative study was to make use of interviewing, questionnaire investigation, and document analysis in the form of textbook, test and examination analysis. These methods provided data that fitted into a grounded theory approach. The study concluded by identifying the list of mathematical topics required for the first year of the core subjects in the BCom degree programme. In addition, the study found that learners who study Mathematics in the National Senior Certificate should be able to cope with the mathematical content included in their BCom degree programme, while learners studying Mathematical Literacy would probably need support in some of the areas of mathematics, especially algebra, in order to cope with the mathematical content included in their BCom degree programme. It makes a valuable contribution towards elucidating the mathematical requirements needed to improve the chances of successful BCom degree programme studies at South African universities. It also draws the contours for starting to design an efficient support course for future “at-risk” students who enter higher education studies.
- Full Text:
- Date Issued: 2009
- Authors: Walton, Marguerite
- Date: 2009
- Subjects: Business mathematics -- South Africa , Mathematics -- Study and teaching (Higher) -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10502 , http://hdl.handle.net/10948/886 , Business mathematics -- South Africa , Mathematics -- Study and teaching (Higher) -- South Africa
- Description: These studies have focused on identifying the mathematical requirements of first-year BCom students at Nelson Mandela Metropolitan University. The research methodology used in this quantitative study was to make use of interviewing, questionnaire investigation, and document analysis in the form of textbook, test and examination analysis. These methods provided data that fitted into a grounded theory approach. The study concluded by identifying the list of mathematical topics required for the first year of the core subjects in the BCom degree programme. In addition, the study found that learners who study Mathematics in the National Senior Certificate should be able to cope with the mathematical content included in their BCom degree programme, while learners studying Mathematical Literacy would probably need support in some of the areas of mathematics, especially algebra, in order to cope with the mathematical content included in their BCom degree programme. It makes a valuable contribution towards elucidating the mathematical requirements needed to improve the chances of successful BCom degree programme studies at South African universities. It also draws the contours for starting to design an efficient support course for future “at-risk” students who enter higher education studies.
- Full Text:
- Date Issued: 2009
Intelligent gripper design and application for automated part recognition and gripping
- Authors: Wang, Jianqiang
- Date: 2002
- Subjects: Automatic control , Robots, Industrial , Robotics
- Language: English
- Type: Thesis , Doctoral , DTech (Engineering)
- Identifier: vital:10816 , http://hdl.handle.net/10948/102 , Automatic control , Robots, Industrial , Robotics
- Description: Intelligent gripping may be achieved through gripper design, automated part recognition, intelligent algorithm for control of the gripper, and on-line decision-making based on sensory data. A generic framework which integrates sensory data, part recognition, decision-making and gripper control to achieve intelligent gripping based on ABB industrial robot is constructed. The three-fingered gripper actuated by a linear servo actuator designed and developed in this project for precise speed and position control is capable of handling a large variety of objects. Generic algorithms for intelligent part recognition are developed. Edge vector representation is discussed. Object geometric features are extracted. Fuzzy logic is successfully utilized to enhance the intelligence of the system. The generic fuzzy logic algorithm, which may also find application in other fields, is presented. Model-based gripping planning algorithm which is capable of extracting object grasp features from its geometric features and reasoning out grasp model for objects with different geometry is proposed. Manipulator trajectory planning solves the problem of generating robot programs automatically. Object-oriented programming technique based on Visual C++ MFC is used to constitute the system software so as to ensure the compatibility, expandability and modular programming design. Hierarchical architecture for intelligent gripping is discussed, which partitions the robot’s functionalities into high-level (modeling, recognizing, planning and perception) layers, and low-level (sensing, interfacing and execute) layers. Individual system modules are integrated seamlessly to constitute the intelligent gripping system.
- Full Text:
- Date Issued: 2002
- Authors: Wang, Jianqiang
- Date: 2002
- Subjects: Automatic control , Robots, Industrial , Robotics
- Language: English
- Type: Thesis , Doctoral , DTech (Engineering)
- Identifier: vital:10816 , http://hdl.handle.net/10948/102 , Automatic control , Robots, Industrial , Robotics
- Description: Intelligent gripping may be achieved through gripper design, automated part recognition, intelligent algorithm for control of the gripper, and on-line decision-making based on sensory data. A generic framework which integrates sensory data, part recognition, decision-making and gripper control to achieve intelligent gripping based on ABB industrial robot is constructed. The three-fingered gripper actuated by a linear servo actuator designed and developed in this project for precise speed and position control is capable of handling a large variety of objects. Generic algorithms for intelligent part recognition are developed. Edge vector representation is discussed. Object geometric features are extracted. Fuzzy logic is successfully utilized to enhance the intelligence of the system. The generic fuzzy logic algorithm, which may also find application in other fields, is presented. Model-based gripping planning algorithm which is capable of extracting object grasp features from its geometric features and reasoning out grasp model for objects with different geometry is proposed. Manipulator trajectory planning solves the problem of generating robot programs automatically. Object-oriented programming technique based on Visual C++ MFC is used to constitute the system software so as to ensure the compatibility, expandability and modular programming design. Hierarchical architecture for intelligent gripping is discussed, which partitions the robot’s functionalities into high-level (modeling, recognizing, planning and perception) layers, and low-level (sensing, interfacing and execute) layers. Individual system modules are integrated seamlessly to constitute the intelligent gripping system.
- Full Text:
- Date Issued: 2002
The impact of government expenditure on economic growth of the economic community of West African states (ECOWAS)
- Authors: Wanjuu, Lazarus Zungwe
- Date: 2016
- Subjects: Economic development -- Africa Africa -- Economic conditions Developing countries -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13261 , vital:27169
- Description: Available statistics on growth trends in the Economic Community of West African States (ECOWAS) are wanting, particularly net per capita growth rates. The analysis of available data from 1970 to 2012 by this study, for instance, shows that the net real GDP growth rate for the ECOWAS is 0.52%. Only four countries had net growth rates above 1% per annum mean growth rate of ECOWAS region. At the estimated growth rate, the prospect of accelerated growth in ECOWAS is very weak. The Barro endogenous growth model states that government provision of services can generate externalities to the private productive activities. Government’s provision of productive services in ECOWAS can ensure long-run per capita output growth without the per capita growth rate running into steady state growth. However, there are divergent views as to whether government provision of services induces long run economic growth. These views are based on different schools of thought. For instance, the economic freedom school argues for minimum government involvement (small governments) to ensure economic and political freedom to induce private investors invest and encourage economic growth. The optimal government school of thought (medium size governments) argues that government spending enhances private productivity growth through the provision of infrastructure, spending on research and development, public education, sewage, other public goods and protection through functional law and order systems. The optimal school of thought also acknowledges that government expenditure can also reduce economic growth through increases in taxation. An increase in taxation reduces the returns on investment of physical and human capital and in research and development (R&D) of private firms. This thesis investigates the impact of government expenditure on the provision of public services on economic growth in ECOWAS. To assess the impact of government expenditure on the provision of services on economic growth of ECOWAS, this thesis assesses whether the size of government, government expenditure and economic institutions promoted economic growth in ECOWAS. The thesis also determines whether per capita government capital expenditure, per capita government consumption expenditure, per capita private capital stock, per capita manufacturing output, per capita services output and per capita agricultural output have any impact on per capita real GDP growth in ECOWAS. To carry out this study, data were collected from United Nations Conference on Trade and Development (UNCTAD) database and Transparency International (TI) database. The data used covered the period of 1970 – 2013. The statistical research methods applied are the time-series methods of panel unit root test, panel co-integration test, and panel regression analysis, using both panel OLS regression models and estimation and inferences in co-integrated panel data regression methods. The panel OLS regression models applied are the panel OLS regression; panel fixed effect model (FEM) regression and the panel random effect model (REM) regression. The estimation and inferences in co-integrated panel data regression models applied are panel VEC regression model, panel DOLS regression and panel FMOLS regression. The panel DOLS regression and panel FMOLS regression models do not have an intercept, unlike their pure time-series models, which have intercepted. To ensure that the parameters estimated are reliable, this thesis conducted diagnostic tests to subject the regression result to scrutiny. The estimated panel data regression using panel OLS regression, panel FEM regression and panel REM regression indicate that the results of the estimated parameters were spurious having both autocorrelations and heteroscedasticity. High values of adjusted R-squares that were approaching one and high significant values of t statistics but very low values of Durbin-Watson Statistics demonstrated the existence of heteroscedasticity and autocorrelation in residuals. The results of the diagnostic tests also show that the DOLS estimated regression model out-performed both VEC and FMOLS regression models based on both aggregate data and per capita data estimated parameters. The results of the parameter estimated using panel VEC and panel FMOLS regression models showed that both panel VEC and panel FMOLS regression models had the problems of their residuals having not only autocorrelations but heteroscedasticity. The panel DOLS regression results were satisfactory, having no multicollinearity, autocorrelations and heteroscedasticity. The estimated panel DOLS regression results were applied to test hypotheses formulated to guide this thesis. Results from panel DOLS estimated parameters show that the existing government size in ECOWAS stimulated economic growth. The results also showed that the government expenditure exhibited an inverted U-shape with respect to economic growth. The thesis also showed that existing government size in ECOWAS significantly stimulated economic growth in the region. The results of regression indicate that economic institutions contribute negatively to the economic growth of the ECOWAS. The results also established that government capital expenditure per capita has significantly engendered economic growth. Government consumption expenditure per capita stimulated economic growth. However, private capital stock per capita has not stimulated economic growth in ECOWAS. Service sector output per capita, agricultural output per capita and manufacturing output per capita stimulated significantly economic growth in the ECOWAS sub-region.
- Full Text:
- Date Issued: 2016
- Authors: Wanjuu, Lazarus Zungwe
- Date: 2016
- Subjects: Economic development -- Africa Africa -- Economic conditions Developing countries -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13261 , vital:27169
- Description: Available statistics on growth trends in the Economic Community of West African States (ECOWAS) are wanting, particularly net per capita growth rates. The analysis of available data from 1970 to 2012 by this study, for instance, shows that the net real GDP growth rate for the ECOWAS is 0.52%. Only four countries had net growth rates above 1% per annum mean growth rate of ECOWAS region. At the estimated growth rate, the prospect of accelerated growth in ECOWAS is very weak. The Barro endogenous growth model states that government provision of services can generate externalities to the private productive activities. Government’s provision of productive services in ECOWAS can ensure long-run per capita output growth without the per capita growth rate running into steady state growth. However, there are divergent views as to whether government provision of services induces long run economic growth. These views are based on different schools of thought. For instance, the economic freedom school argues for minimum government involvement (small governments) to ensure economic and political freedom to induce private investors invest and encourage economic growth. The optimal government school of thought (medium size governments) argues that government spending enhances private productivity growth through the provision of infrastructure, spending on research and development, public education, sewage, other public goods and protection through functional law and order systems. The optimal school of thought also acknowledges that government expenditure can also reduce economic growth through increases in taxation. An increase in taxation reduces the returns on investment of physical and human capital and in research and development (R&D) of private firms. This thesis investigates the impact of government expenditure on the provision of public services on economic growth in ECOWAS. To assess the impact of government expenditure on the provision of services on economic growth of ECOWAS, this thesis assesses whether the size of government, government expenditure and economic institutions promoted economic growth in ECOWAS. The thesis also determines whether per capita government capital expenditure, per capita government consumption expenditure, per capita private capital stock, per capita manufacturing output, per capita services output and per capita agricultural output have any impact on per capita real GDP growth in ECOWAS. To carry out this study, data were collected from United Nations Conference on Trade and Development (UNCTAD) database and Transparency International (TI) database. The data used covered the period of 1970 – 2013. The statistical research methods applied are the time-series methods of panel unit root test, panel co-integration test, and panel regression analysis, using both panel OLS regression models and estimation and inferences in co-integrated panel data regression methods. The panel OLS regression models applied are the panel OLS regression; panel fixed effect model (FEM) regression and the panel random effect model (REM) regression. The estimation and inferences in co-integrated panel data regression models applied are panel VEC regression model, panel DOLS regression and panel FMOLS regression. The panel DOLS regression and panel FMOLS regression models do not have an intercept, unlike their pure time-series models, which have intercepted. To ensure that the parameters estimated are reliable, this thesis conducted diagnostic tests to subject the regression result to scrutiny. The estimated panel data regression using panel OLS regression, panel FEM regression and panel REM regression indicate that the results of the estimated parameters were spurious having both autocorrelations and heteroscedasticity. High values of adjusted R-squares that were approaching one and high significant values of t statistics but very low values of Durbin-Watson Statistics demonstrated the existence of heteroscedasticity and autocorrelation in residuals. The results of the diagnostic tests also show that the DOLS estimated regression model out-performed both VEC and FMOLS regression models based on both aggregate data and per capita data estimated parameters. The results of the parameter estimated using panel VEC and panel FMOLS regression models showed that both panel VEC and panel FMOLS regression models had the problems of their residuals having not only autocorrelations but heteroscedasticity. The panel DOLS regression results were satisfactory, having no multicollinearity, autocorrelations and heteroscedasticity. The estimated panel DOLS regression results were applied to test hypotheses formulated to guide this thesis. Results from panel DOLS estimated parameters show that the existing government size in ECOWAS stimulated economic growth. The results also showed that the government expenditure exhibited an inverted U-shape with respect to economic growth. The thesis also showed that existing government size in ECOWAS significantly stimulated economic growth in the region. The results of regression indicate that economic institutions contribute negatively to the economic growth of the ECOWAS. The results also established that government capital expenditure per capita has significantly engendered economic growth. Government consumption expenditure per capita stimulated economic growth. However, private capital stock per capita has not stimulated economic growth in ECOWAS. Service sector output per capita, agricultural output per capita and manufacturing output per capita stimulated significantly economic growth in the ECOWAS sub-region.
- Full Text:
- Date Issued: 2016
A psychobiographical study of Temple Grandin
- Authors: Wannenburg, Nicola
- Date: 2018
- Subjects: Grandin, Temple , Psychology Biographical methods , Psychoanalysis , Autistic women United States Biography , Women animal specialists United States Biography , Developmental psychology , Erikson, Erik H (Erik Homburger), 1902-1994
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/57358 , vital:26877
- Description: Psychobiographical researchers methodically formulate life histories and interpret them by means of psychological theories. The research typically focuses on exemplary and completed lives. The cases that are studied are usually of individuals who are of particular interest to society as a result of excelling in their particular fields, be they to benefit or detriment of society. Temple Grandin was chosen for this study using purposive sampling as she meets the psychobiographical requirement of being an extraordinary individual. As an individual with autism Grandin faced many challenges growing up. Despite a difficult and absent beginning, Grandin developed into a stable and scientifically creative adult who contributes to society. She excels as an animal scientist and designer of humane livestock handling facilities and has an international reputation for her contribution to the livestock industry and animal welfare. The primary aim of this study is to describe and interpret the life of Temple Grandin through Erikson’s (1950/1973) theory of psychosocial development. A mixed method approach (Yin, 2006) was employed for the conduction of this study. The overarching data processing and analysis guidelines for this study were provided by Miles and Huberman (1994, 2002a, 2002b). The conduction of the processing and analysis of data was aided by Alexander’s (1988, 1990) method of asking the data questions as well as an integration of Yin’s (2014) time series analysis with Erikson’s (1950/1973) triple bookkeeping approach. This study contributes to the development of psychobiographical research in South Africa as well as to personality and developmental theory.
- Full Text:
- Date Issued: 2018
- Authors: Wannenburg, Nicola
- Date: 2018
- Subjects: Grandin, Temple , Psychology Biographical methods , Psychoanalysis , Autistic women United States Biography , Women animal specialists United States Biography , Developmental psychology , Erikson, Erik H (Erik Homburger), 1902-1994
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/57358 , vital:26877
- Description: Psychobiographical researchers methodically formulate life histories and interpret them by means of psychological theories. The research typically focuses on exemplary and completed lives. The cases that are studied are usually of individuals who are of particular interest to society as a result of excelling in their particular fields, be they to benefit or detriment of society. Temple Grandin was chosen for this study using purposive sampling as she meets the psychobiographical requirement of being an extraordinary individual. As an individual with autism Grandin faced many challenges growing up. Despite a difficult and absent beginning, Grandin developed into a stable and scientifically creative adult who contributes to society. She excels as an animal scientist and designer of humane livestock handling facilities and has an international reputation for her contribution to the livestock industry and animal welfare. The primary aim of this study is to describe and interpret the life of Temple Grandin through Erikson’s (1950/1973) theory of psychosocial development. A mixed method approach (Yin, 2006) was employed for the conduction of this study. The overarching data processing and analysis guidelines for this study were provided by Miles and Huberman (1994, 2002a, 2002b). The conduction of the processing and analysis of data was aided by Alexander’s (1988, 1990) method of asking the data questions as well as an integration of Yin’s (2014) time series analysis with Erikson’s (1950/1973) triple bookkeeping approach. This study contributes to the development of psychobiographical research in South Africa as well as to personality and developmental theory.
- Full Text:
- Date Issued: 2018
A development training support model for entrepreneurs in South Africa
- Authors: Ward, Graham Bernard
- Date: 2017
- Subjects: Entrepreneurship -- South Africa , Entrepreneurship -- Training of -- South Africa new business enterprises -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/13546 , vital:27221
- Description: Recent years have seen the decline of entrepreneurial activity in South Africa. This is especially concerning in that, officially, 27.7% of South Africans are unemployed. The unofficial unemployment figures are closer to 50%. The South African economy is battling to recover from the world economic crisis of 2009/10, putting pressure on government to alleviate growing unemployment and curtail social unrest. Furthermore, a South African economy which thrives on entrepreneurial activity will become more competitive from a global perspective. The purpose of this study is to contribute to the promotion and development of entrepreneurship in South Africa, in an effort to combat the problems listed above. In order to achieve this purpose, the objective was to develop and test a model which could be used in the development of entrepreneurs. The rationale is that, if the factors which affect entrepreneurship could be identified and tested, then recommendations could be made which could promote the development of entrepreneurs in South Africa. The approach was as follows: Perform a literature review which would cover both global and local (South African) approaches to developmental training for entrepreneurs; Develop a theoretical model comprising of identified factors which formed the base for the data collection; Develop a measuring instrument to test the relationships described in the theoretical model empirically; • Empirically test the proposed model and suggested hypotheses by means of sourcing data from entrepreneurs in South Africa and statistically analyse the sourced data; Formulate the final theoretical model to support the research objectives; and Propose recommendations based on the results of the statistical analysis. The focus of the literature study was on two main areas: trends in global developmental training, and South African initiatives to stimulate developmental training of entrepreneurs. The literature on global entrepreneurial development highlights two distinct categories for entrepreneurial development: 1) entrepreneurial education and 2) entrepreneurial training. The literature study concerning South African methodologies for developmental training for entrepreneurs, focused on current methods employed and highlighted areas on which improvements should be concentrated. From the literature study on both global and South African developmental training methods, ten independent variables (entrepreneurial culture; socio-emotional attributes; acquiring business skills; industry experience; opportunity identification; regulatory barriers; economic barriers; outside advice; formal training and informal training were identified as factors affecting entrepreneurial developmental training. All the variables were hypothesised as they were perceived to influence significantly the dependent variables: perceived global success as an entrepreneur and perceived individual success as an entrepreneur. These factors, clearly defined and operationalised, were structured in a questionnaire which was sent randomly to South African business owners. Data were collected from 332 respondents and subjected to various statistical analysis techniques. Firstly, Exploratory Factor Analysis (EFA) was conducted to assess the discriminant validity of the research instrument. Secondly, Cronbach’s alpha coefficients were calculated for each of the identified factors to confirm the reliability of the research instrument. The significance of the hypothesised relationships in the revised model were then tested by using the statistical technique known as Structural Equation Modelling (SEM) This study contributed to this specific field of knowledge.
- Full Text:
- Date Issued: 2017
- Authors: Ward, Graham Bernard
- Date: 2017
- Subjects: Entrepreneurship -- South Africa , Entrepreneurship -- Training of -- South Africa new business enterprises -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: http://hdl.handle.net/10948/13546 , vital:27221
- Description: Recent years have seen the decline of entrepreneurial activity in South Africa. This is especially concerning in that, officially, 27.7% of South Africans are unemployed. The unofficial unemployment figures are closer to 50%. The South African economy is battling to recover from the world economic crisis of 2009/10, putting pressure on government to alleviate growing unemployment and curtail social unrest. Furthermore, a South African economy which thrives on entrepreneurial activity will become more competitive from a global perspective. The purpose of this study is to contribute to the promotion and development of entrepreneurship in South Africa, in an effort to combat the problems listed above. In order to achieve this purpose, the objective was to develop and test a model which could be used in the development of entrepreneurs. The rationale is that, if the factors which affect entrepreneurship could be identified and tested, then recommendations could be made which could promote the development of entrepreneurs in South Africa. The approach was as follows: Perform a literature review which would cover both global and local (South African) approaches to developmental training for entrepreneurs; Develop a theoretical model comprising of identified factors which formed the base for the data collection; Develop a measuring instrument to test the relationships described in the theoretical model empirically; • Empirically test the proposed model and suggested hypotheses by means of sourcing data from entrepreneurs in South Africa and statistically analyse the sourced data; Formulate the final theoretical model to support the research objectives; and Propose recommendations based on the results of the statistical analysis. The focus of the literature study was on two main areas: trends in global developmental training, and South African initiatives to stimulate developmental training of entrepreneurs. The literature on global entrepreneurial development highlights two distinct categories for entrepreneurial development: 1) entrepreneurial education and 2) entrepreneurial training. The literature study concerning South African methodologies for developmental training for entrepreneurs, focused on current methods employed and highlighted areas on which improvements should be concentrated. From the literature study on both global and South African developmental training methods, ten independent variables (entrepreneurial culture; socio-emotional attributes; acquiring business skills; industry experience; opportunity identification; regulatory barriers; economic barriers; outside advice; formal training and informal training were identified as factors affecting entrepreneurial developmental training. All the variables were hypothesised as they were perceived to influence significantly the dependent variables: perceived global success as an entrepreneur and perceived individual success as an entrepreneur. These factors, clearly defined and operationalised, were structured in a questionnaire which was sent randomly to South African business owners. Data were collected from 332 respondents and subjected to various statistical analysis techniques. Firstly, Exploratory Factor Analysis (EFA) was conducted to assess the discriminant validity of the research instrument. Secondly, Cronbach’s alpha coefficients were calculated for each of the identified factors to confirm the reliability of the research instrument. The significance of the hypothesised relationships in the revised model were then tested by using the statistical technique known as Structural Equation Modelling (SEM) This study contributed to this specific field of knowledge.
- Full Text:
- Date Issued: 2017
Interactions between figs (Ficus spp., Moraceae) and fig wasps (Chalcidoidea, Agaonidae)
- Authors: Ware, Anthony Brian
- Date: 1993
- Subjects: Fig -- South Africa Fig wasp -- South Africa Pollination Agaonidae Chalcid wasps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5719 , http://hdl.handle.net/10962/d1005405
- Description: Fig trees (Ficus spp., Moraceae) and fig wasps (Chalcidoidea, Agaonidae) are uniquely associated. In one fig wasp group, the pollinators (Agaoninae), each species is generally host species-specific. The relationship is one of obligate mutualism where the wasps provide pollination services and in return utilises some of the ovules for larval development. Non-pollinating fig wasps (generally belonging to subfamilies other than the Agaoninae) may be gallers or parasitoids, and can also be host species-specific. In the accompanying studies we examined the factors governing the interactions between fig wasps and their host trees. Surveys of fig trees and their associated pollinating fig wasps conducted in southern Africa, Madagascar and The Comores generally confirmed their specific relationships. An examination of F. sycomorlls in Madagascar resulted in the reclassification of F. sakalavarum as a distinct species with its own specific pollinator species. Biological and chemical evidence is presented demonstrating that the pollinators were able to distinguish their hosts through volatiles which emanated from the figs when they were ready to be pollinated. Environmental factors were found to influence wasp behaviour. Ambient temperature governed the timing of wasp emergence from their natal figs. When dispersing from their natal figs, the fig wasps flew upwards and then were blown downwind. Once nearing trees bearing figs ready to be pollinated, the wasps lost height and flew upwind towards the trees. E. baijnathi females apparently avoided figs which already contained a conspecific foundress. Scanning electron microscope studies of pollinating female fig wasp antennae showed that while all the species possessed multiporous plate sensilla, in only a few species were these sensilla elongated. Multiporous plate sensilla elongation is rare or absent among other female chalcids and may have evolved within the Agaoninae in order to facilitate their location on receptive host figs. Pollinator choice specificity appears to break down in a number of cases. In the first case examined, two pollinator species were recorded from the figs of African F. sycomorus. One. C. arabicus, pollinates the figs while the other, C. galili, acts as a 'cuckoo' by utilising some of ovules for oviposition without providing pollen. In the second case three pollinating fig wasp species were recorded from the rigs of F. lutea. Two were found to be incidental visitors and were not specifically attracted to the tree. The hybrid seeds from these crosses were successfully germinated but the seedlings did not grow passed the cotyledon stage of their development. In the concluding study the consequences of Ficus phenology and the structure of the fig's unusual inflorescence on the nonpollinating fig wasp community were examined. Various factors affecting the population levels and species richness were also examined. Future possible research directions were discussed.
- Full Text:
- Date Issued: 1993
- Authors: Ware, Anthony Brian
- Date: 1993
- Subjects: Fig -- South Africa Fig wasp -- South Africa Pollination Agaonidae Chalcid wasps
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5719 , http://hdl.handle.net/10962/d1005405
- Description: Fig trees (Ficus spp., Moraceae) and fig wasps (Chalcidoidea, Agaonidae) are uniquely associated. In one fig wasp group, the pollinators (Agaoninae), each species is generally host species-specific. The relationship is one of obligate mutualism where the wasps provide pollination services and in return utilises some of the ovules for larval development. Non-pollinating fig wasps (generally belonging to subfamilies other than the Agaoninae) may be gallers or parasitoids, and can also be host species-specific. In the accompanying studies we examined the factors governing the interactions between fig wasps and their host trees. Surveys of fig trees and their associated pollinating fig wasps conducted in southern Africa, Madagascar and The Comores generally confirmed their specific relationships. An examination of F. sycomorlls in Madagascar resulted in the reclassification of F. sakalavarum as a distinct species with its own specific pollinator species. Biological and chemical evidence is presented demonstrating that the pollinators were able to distinguish their hosts through volatiles which emanated from the figs when they were ready to be pollinated. Environmental factors were found to influence wasp behaviour. Ambient temperature governed the timing of wasp emergence from their natal figs. When dispersing from their natal figs, the fig wasps flew upwards and then were blown downwind. Once nearing trees bearing figs ready to be pollinated, the wasps lost height and flew upwind towards the trees. E. baijnathi females apparently avoided figs which already contained a conspecific foundress. Scanning electron microscope studies of pollinating female fig wasp antennae showed that while all the species possessed multiporous plate sensilla, in only a few species were these sensilla elongated. Multiporous plate sensilla elongation is rare or absent among other female chalcids and may have evolved within the Agaoninae in order to facilitate their location on receptive host figs. Pollinator choice specificity appears to break down in a number of cases. In the first case examined, two pollinator species were recorded from the figs of African F. sycomorus. One. C. arabicus, pollinates the figs while the other, C. galili, acts as a 'cuckoo' by utilising some of ovules for oviposition without providing pollen. In the second case three pollinating fig wasp species were recorded from the rigs of F. lutea. Two were found to be incidental visitors and were not specifically attracted to the tree. The hybrid seeds from these crosses were successfully germinated but the seedlings did not grow passed the cotyledon stage of their development. In the concluding study the consequences of Ficus phenology and the structure of the fig's unusual inflorescence on the nonpollinating fig wasp community were examined. Various factors affecting the population levels and species richness were also examined. Future possible research directions were discussed.
- Full Text:
- Date Issued: 1993
Enlarging the place of human rights and development in international trade regulation: an evaluation of the problems and prospects of incorporating a social clause in the legal framework of the World Trade Organization
- Authors: Warikandwa, Tapiwa Victor
- Date: 2012
- Subjects: Social Clause -- Development -- International Trade Regulation -- Human Rights -- World Trade Organization
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: vital:11120 , http://hdl.handle.net/10353/d1015224
- Description: An agreement on the inclusion of a social clause in the World Trade Organization‟s (WTO) multilateral trade agreements largely depends on reassuring objecting member states that such inclusion will contribute to an improved recognition of core labour standards in trade, without altering the competitive advantage of one trading partner over another. Reassurance must be given to the effect that incorporating a social clause in the WTO legal framework would not be used as a trade restricting mechanism which might have direct, negative effects on the development of countries worldwide. Such an argument may not be won easily from a legal and economic perspective. There is an omnipresent conflict at the international level between the basic values underlying multilateral trade agreements and principles governing the protection of core labour standards. On the one hand, supporting the stance of free trade is the fundamental force of profit maximization while on the other hand, and in direct opposition to this market driven value system, are human rights-based calls for recognising core labour standards in employment matters related to trade. Increased international trade is a powerful tool for tackling poverty and social misery worldwide. It could thus be important to adopt a legal framework in the multilateral trade system to harness potential opportunities a trade-labour linkage could provide. In that case, the legal questions of whether or not there should be a tradeoff between the right to trade and compliance with core labour standards and whether a social clause in the WTO would achieve this purpose had to be addressed. However, without a compatible underpinning legal framework of universally accepted trade-labour standards, incorporating a social clause in the WTO would be a misplaced legal objective which is unachievable as it could lead to a conflict between the WTO and the International Labour Organisation (ILO) and at most could create a legal fiction whose results may not be positively measurable. Setting two international legal norms at conflict with each other is systematically studied as a conflict in which the values of the global market economy are in a supposed confrontation with those protecting core labour standards as human rights. Therefore, this study undertook a contemporary legal analysis of the possibilities and challenges of incorporating a social clause in the WTO for purposes of entrenching the protection of core labour standards. It put forward arguments and tentative proposals for a trade-labour linkage legal framework which could dispel calls for excluding a social clause in the WTO.
- Full Text:
- Date Issued: 2012
- Authors: Warikandwa, Tapiwa Victor
- Date: 2012
- Subjects: Social Clause -- Development -- International Trade Regulation -- Human Rights -- World Trade Organization
- Language: English
- Type: Thesis , Doctoral , LLD
- Identifier: vital:11120 , http://hdl.handle.net/10353/d1015224
- Description: An agreement on the inclusion of a social clause in the World Trade Organization‟s (WTO) multilateral trade agreements largely depends on reassuring objecting member states that such inclusion will contribute to an improved recognition of core labour standards in trade, without altering the competitive advantage of one trading partner over another. Reassurance must be given to the effect that incorporating a social clause in the WTO legal framework would not be used as a trade restricting mechanism which might have direct, negative effects on the development of countries worldwide. Such an argument may not be won easily from a legal and economic perspective. There is an omnipresent conflict at the international level between the basic values underlying multilateral trade agreements and principles governing the protection of core labour standards. On the one hand, supporting the stance of free trade is the fundamental force of profit maximization while on the other hand, and in direct opposition to this market driven value system, are human rights-based calls for recognising core labour standards in employment matters related to trade. Increased international trade is a powerful tool for tackling poverty and social misery worldwide. It could thus be important to adopt a legal framework in the multilateral trade system to harness potential opportunities a trade-labour linkage could provide. In that case, the legal questions of whether or not there should be a tradeoff between the right to trade and compliance with core labour standards and whether a social clause in the WTO would achieve this purpose had to be addressed. However, without a compatible underpinning legal framework of universally accepted trade-labour standards, incorporating a social clause in the WTO would be a misplaced legal objective which is unachievable as it could lead to a conflict between the WTO and the International Labour Organisation (ILO) and at most could create a legal fiction whose results may not be positively measurable. Setting two international legal norms at conflict with each other is systematically studied as a conflict in which the values of the global market economy are in a supposed confrontation with those protecting core labour standards as human rights. Therefore, this study undertook a contemporary legal analysis of the possibilities and challenges of incorporating a social clause in the WTO for purposes of entrenching the protection of core labour standards. It put forward arguments and tentative proposals for a trade-labour linkage legal framework which could dispel calls for excluding a social clause in the WTO.
- Full Text:
- Date Issued: 2012
Impacts of wildlife and cattle grazing on spider (araneae) biodiversity in a highland savanna ecosystem, in Laikipia, Central Kenya
- Authors: Warui, Charles Mwaura
- Date: 2005
- Subjects: Spiders -- Kenya Environmental monitoring -- Kenya Savanna ecology -- Kenya Biodiversity -- Kenya Species diversity -- Kenya Wildlife management -- Kenya Herbivores -- Ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5712 , http://hdl.handle.net/10962/d1005398
- Description: Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.
- Full Text:
- Date Issued: 2005
- Authors: Warui, Charles Mwaura
- Date: 2005
- Subjects: Spiders -- Kenya Environmental monitoring -- Kenya Savanna ecology -- Kenya Biodiversity -- Kenya Species diversity -- Kenya Wildlife management -- Kenya Herbivores -- Ecology -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5712 , http://hdl.handle.net/10962/d1005398
- Description: Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of resolution, namely the overall community, guilds and individual species. This is the first controlled replicated experimental study on the effects on invertebrates (spiders) by different land uses (access by large herbivores). A total of 10,487 individuals from 132 species belonging to 30 families were recorded. The family Salticidae had the highest number of species (24), followed by Gnaphosidae (20), Araneidae and Lycosidae (15 each), Theridiidae and Thomisidae (8 each) and Zodariidae (4). Most of the other families had fewer than 4 species. Throughout the study period, species not previously sampled emerged after rainfall peaks. Exclosure treatments affected plant cover, spider diversity and total species mainly through the effects of cattle, whose presence significantly reduced relative vegetation cover. An increase in vegetation cover significantly increased the diversity, total species and species evenness of the overall spider community (total samples data set). Megaherbivores and mesoherbivores had no effects on overall spider diversity. Relative vegetation cover explained approximately 20-30% of variation in community diversity, species richness and species evenness. At the guild level of resolution, the exclosure treatments had no significant effects on diversity, species richness and species evenness of web builders, plant wanderers and ground wanderers. Plant wanderers were significantly and positively correlated with relative vegetation cover, which explained 17% of variation in their diversity. Six individual species responded strongly and in contrasting ways to the same environmental variables, indicating that this level was more sensitive to environmental changes than guilds or the overall spider community. Spider diversity, relative vegetation cover and rainfall varied at a temporal scale of months and not at a spatial scale of hundreds of metres. Only species diversity and species richness from sweep-netting samples and total species from pitfall-trapping varied significantly at a spatial scale of hundreds of metres. Ordination analysis revealed that sweep-netting samples were a better indicator of grazing impacts than pitfalltrapping or combined samples and grouped to reflect cattle grazing, non-cattle grazing and to a small extent the control treatments. Other ordination analyses showed that only samples from sweep-netting and not from pitfall-trapping, were spatially partitioned at a scale of hundreds of metres. This study concludes that the spider fauna of black cotton soil habitats is rich and useful for environmental monitoring and that monitoring of several individual species as indicator of grazing impacts in savanna could be useful and relatively easy.
- Full Text:
- Date Issued: 2005
Effects of Vigna unguiculata and Lablab purpureus on methanogenesis, haematological parameters and the quality of meat from Xhosa Lop Ear goats
- Authors: Washaya, Soul
- Date: 2017
- Subjects: Legumes Forage Forage plants
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/9996 , vital:35249
- Description: The objective of the current study was to evaluate the nutritive value of forage legumes Lablab purpureus (Lablab) and Vigna unguiculata (Cowpea) and their effects on intake, growth, blood parameters and meat quality in Xhosa goats. Forages were established at UFH research farm in the summer of the 2014 /15 growing season in blocks measuring 8m width x 16m long for each legume, replicated three times, making a total of four blocks, and eight treatment units for each legume. Samples were collected at three different stages of growth of preanthesis, anthesis and post anthesis for biomass yield determination. A homogenous sub-sample was then oven dried for 72 hours at 60 0C. After drying the forage samples were milled through a 1mm screen and a 20g sample from each stage of growth and forage sample was subjected to proximate analysis, in-vitro digestibility and anti-nutrient evaluation. The in-vitro digestibility experiment was done with rumen liquor of cattle and sheep collected from an abbatoir. Tannins, total phenolics and sapponins were the only anti-nutrients evaluated as they are perceived to influence methanogenesis in ruminat animals. At 50percent flowering, forage legumes were harvested for hay making which was then used in an in-vivo trial to evaluate the nutritive value of forages. This trial was conducted using eighteen one-year-old goats of average weight 14.2±0.24 kg over a period of sixty days. The results showed that biomass yield, which increased with stage of growth, was significantly higher (P < 0.05) for Lablab than Cowpea (7.968t/ha vs 7.105t/ha). Cowpea exhibited higher moisture content (7.72percent), Ash (13.11percent), acid detergent fibre (ADF) (38.42percent) and crude protein (CP) (20.23percent) than Lablab which had 7.50percent, 11.45 percent, 36.17percent and 19percent, respectively. Lablab forage had significantly higher (P < 0.05) fat content (2.41percent), neutral detergent fibre (NDF) (49.27percent) and hemicellulose (13.07percent) than Cowpea which had 2.1percent; 46.91percent and 8.48percent, respectively. The stage of growth significantly (P < 0.05) affected the mineral content of both forages. Lablab showed significantly higher (P < 0.05) values (1.22percent 0.55percent, 2.67percent) than Cowpea (1.00percent, 0.45percent, 2.30percent) for calcium (Ca), phosphorus (P), and potassium (K) respectively. Lablab forage had significantly higher (P < 0.05) tannin (3.345mgCAE/gDM), phenolic (13.47mgGAE/gDM) and saponin (0.75percent) content compared to Cowpea with values of 1.494mgCAEg/DM; 9.402mgGAE/gDM and vs 1.55percent respectively. The tannin content significantly influenced in-vitro digestibility and enteric methane production. The forage type, harvesting stage and inoculum source significantly (P < 0.05) affected the in-vitro digestibility of the forages. The in-vitro dry matter (IVDM) and in-vitro organic matter (IVOM) digestibility was significantly higher (P < 0.05) for Lablab (41.13percent; 39.63percent) than Cowpea (39.86percent; 19.44percent), respectively. Both forages recorded higher dry matter (DM) digestibility coefficients at anthesis stage of growth 61.58percent, and 51.5 percent for Lablab and Cowpea respectively. The IVOM digestibility increased with stage of harvest (23.7percent to 25.57percent) for Cowpea while Lablab showed a decrease (44.6 percent to 43.9percent) when cattle inoculum was used. The IVDM digestibility was higher (P < 0.05) for Lablab (50.5percent) when cattle inoculum was used while Cowpea was observed to have higher digestibility co-efficiencies (38.54percent) when sheep inoculum was used. Cowpea had lower (P < 0.05) IVOM digestibility than Lablab (19.44percent) vs. 39.6percent). Lablab exhibited higher (P < 0.05) metabolisable energy (ME) values than Cowpea (6.21 vs. 2.70 MJ/kgDM). In the feeding study, the total DM intake by goats for Lablab was higher (P < 0.05) compared to Cowpea (688.1 vs. 607.8 g/head/ day). There was a positive (P < 0.05) correlation between dry matter intake and average daily gain (r= 0.8513, and r=0.5279) for Cowpea and Lablab respectively. Lablab and Cowpea promoted growth of Xhosa goats at a rate of 35.0g/d; and 38.3g/d, respectively which was not significantly different (P > 0.05). However, this growth was associated with a significantly higher (P < 0.05) food conversion ratio (FCR) of 19.16 vs 18.11 for Cowpea and Lablab, respectively. The apparent DM, non structural carbohydrate (NSC) nutrient digestibilities were significantly different (P < 0.05) for Lablab and Cowpea. Furthermore sex of animal influenced significantly (P < 0.05) the DM, ADF, NSC and NDF digestibilities. Lablab and Cowpea did not influence (P > 0.05) individual VFA molar concentrations in both sexes. However, animals fed Lablab had significantly higher butyrate concentrations (P < 0.05). Lablab and Cowpea forages significantly lowered (P > 0.05) enteric methane production in goats compared to a concentrate diet, and this was related to animal activity. Animals produced significantly more (P < 0.05) methane gas when ruminating than feeding or just standing. The average methane produced each year was lower but not significant (P > 0.05) for animals fed Cowpea than Lablab (4.602kg CH4, vs. 4.719kg CH4) when expressed per year. Male animals produced more gas than females with values of 17.40L/day; 12.46 g/kg DMI and 0.126g/day vs. 15.47L/day, 12.28 g/kg DMI, and 0.0109g/day, respectively. Forage legumes had no significant effects (P > 0.05) on serum total proteins (TP), globulin, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma- glutamyl transferase (GGT) concentrations, but serum concentration of albumin was influenced by the diets (P < 0.05). Sex of animals significantly influenced ALP concentration (P < 0.05) with male animals exhibiting higer ALP values than females. Measured over time, the plasma concentration of urea and ALP significantly increased (P < 0.05) while creatinine and cholesterol concentration decreased (P < 0.05). Although the overall serum concentration of urea, total proteins, globulin, creatinine, ALT, ALP and GGT remained unchanged among the treatments and between sexes; treatment by sex, treatment by day and sex by day interactions were significant (P < 0.05). The white blood cell (WBC), red blood cell (RBC), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), haemoglobin, haematocrite, platelet and mean platelet volume (MPV) levels were similar among treatments and between sexes (P > 0.05). The WBC decreased with time by 8.07 x10 9/l while mean crepuscular volume (MCV) increased by 11.83(fl) from day 15 to day 55. Treatment diets significantly (P < 0.05) influenced neutrophile (percent) content while sex influenced basophile (percent) content. There were no treatment or sex effects (P > 0.05) on lymphocytes (percent), monocytes (percent) and eosinophiles (percent). In the meat quality study, the dietary treatments and sex had a significant (P < 0.05) effect on dressing out percent (DPpercent), initial pH, redness (a*), yellowness (b*), Warner Blartze Shear force (WBS) , drip loss and cooking loss in the chevon from Xhosa goats. Compared with a commercial pellet diet, Lablab and Cowpea diets resulted in similar slaughter body weights (SBW), hot carcass weight (HCW) and cold dressed mass (CDM) of carcasses. However, female animals exhibited a significantly (P < 0.05) higher DPpercent than male animals (42.3percent vs. 38.9percent) for all treatments. The male animals exhibited significantly (P < 0.05) higher pH values one hour after slaughter than females (5.79 vs 5.67). Neverthreless the diet and gender did not significantly (P > 0.05) affect the ultimate pH (pHu). Meat samples from male animals had significantly (P < 0.05) higher redness values than females. Feeding cowpea significantly (P < 0.05) increased meat redness with the least drip loss of chevon. Female animals produced significantly (P < 0.05) tougher chevon compared to male animals; 4.16kg and 3.36kg for female and male, respectively. Lablab and Cowpea posses high CP levels and moderately lower NDF with high ADF values that influences dry matter intake (DMI), digestibility and growth of goats. These forage legumes meet animal requirements for fat, ADF, NDF, CP, Ca, Mn, zinc and Cu and their biomass yield is satisfactory.
- Full Text:
- Date Issued: 2017
- Authors: Washaya, Soul
- Date: 2017
- Subjects: Legumes Forage Forage plants
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/9996 , vital:35249
- Description: The objective of the current study was to evaluate the nutritive value of forage legumes Lablab purpureus (Lablab) and Vigna unguiculata (Cowpea) and their effects on intake, growth, blood parameters and meat quality in Xhosa goats. Forages were established at UFH research farm in the summer of the 2014 /15 growing season in blocks measuring 8m width x 16m long for each legume, replicated three times, making a total of four blocks, and eight treatment units for each legume. Samples were collected at three different stages of growth of preanthesis, anthesis and post anthesis for biomass yield determination. A homogenous sub-sample was then oven dried for 72 hours at 60 0C. After drying the forage samples were milled through a 1mm screen and a 20g sample from each stage of growth and forage sample was subjected to proximate analysis, in-vitro digestibility and anti-nutrient evaluation. The in-vitro digestibility experiment was done with rumen liquor of cattle and sheep collected from an abbatoir. Tannins, total phenolics and sapponins were the only anti-nutrients evaluated as they are perceived to influence methanogenesis in ruminat animals. At 50percent flowering, forage legumes were harvested for hay making which was then used in an in-vivo trial to evaluate the nutritive value of forages. This trial was conducted using eighteen one-year-old goats of average weight 14.2±0.24 kg over a period of sixty days. The results showed that biomass yield, which increased with stage of growth, was significantly higher (P < 0.05) for Lablab than Cowpea (7.968t/ha vs 7.105t/ha). Cowpea exhibited higher moisture content (7.72percent), Ash (13.11percent), acid detergent fibre (ADF) (38.42percent) and crude protein (CP) (20.23percent) than Lablab which had 7.50percent, 11.45 percent, 36.17percent and 19percent, respectively. Lablab forage had significantly higher (P < 0.05) fat content (2.41percent), neutral detergent fibre (NDF) (49.27percent) and hemicellulose (13.07percent) than Cowpea which had 2.1percent; 46.91percent and 8.48percent, respectively. The stage of growth significantly (P < 0.05) affected the mineral content of both forages. Lablab showed significantly higher (P < 0.05) values (1.22percent 0.55percent, 2.67percent) than Cowpea (1.00percent, 0.45percent, 2.30percent) for calcium (Ca), phosphorus (P), and potassium (K) respectively. Lablab forage had significantly higher (P < 0.05) tannin (3.345mgCAE/gDM), phenolic (13.47mgGAE/gDM) and saponin (0.75percent) content compared to Cowpea with values of 1.494mgCAEg/DM; 9.402mgGAE/gDM and vs 1.55percent respectively. The tannin content significantly influenced in-vitro digestibility and enteric methane production. The forage type, harvesting stage and inoculum source significantly (P < 0.05) affected the in-vitro digestibility of the forages. The in-vitro dry matter (IVDM) and in-vitro organic matter (IVOM) digestibility was significantly higher (P < 0.05) for Lablab (41.13percent; 39.63percent) than Cowpea (39.86percent; 19.44percent), respectively. Both forages recorded higher dry matter (DM) digestibility coefficients at anthesis stage of growth 61.58percent, and 51.5 percent for Lablab and Cowpea respectively. The IVOM digestibility increased with stage of harvest (23.7percent to 25.57percent) for Cowpea while Lablab showed a decrease (44.6 percent to 43.9percent) when cattle inoculum was used. The IVDM digestibility was higher (P < 0.05) for Lablab (50.5percent) when cattle inoculum was used while Cowpea was observed to have higher digestibility co-efficiencies (38.54percent) when sheep inoculum was used. Cowpea had lower (P < 0.05) IVOM digestibility than Lablab (19.44percent) vs. 39.6percent). Lablab exhibited higher (P < 0.05) metabolisable energy (ME) values than Cowpea (6.21 vs. 2.70 MJ/kgDM). In the feeding study, the total DM intake by goats for Lablab was higher (P < 0.05) compared to Cowpea (688.1 vs. 607.8 g/head/ day). There was a positive (P < 0.05) correlation between dry matter intake and average daily gain (r= 0.8513, and r=0.5279) for Cowpea and Lablab respectively. Lablab and Cowpea promoted growth of Xhosa goats at a rate of 35.0g/d; and 38.3g/d, respectively which was not significantly different (P > 0.05). However, this growth was associated with a significantly higher (P < 0.05) food conversion ratio (FCR) of 19.16 vs 18.11 for Cowpea and Lablab, respectively. The apparent DM, non structural carbohydrate (NSC) nutrient digestibilities were significantly different (P < 0.05) for Lablab and Cowpea. Furthermore sex of animal influenced significantly (P < 0.05) the DM, ADF, NSC and NDF digestibilities. Lablab and Cowpea did not influence (P > 0.05) individual VFA molar concentrations in both sexes. However, animals fed Lablab had significantly higher butyrate concentrations (P < 0.05). Lablab and Cowpea forages significantly lowered (P > 0.05) enteric methane production in goats compared to a concentrate diet, and this was related to animal activity. Animals produced significantly more (P < 0.05) methane gas when ruminating than feeding or just standing. The average methane produced each year was lower but not significant (P > 0.05) for animals fed Cowpea than Lablab (4.602kg CH4, vs. 4.719kg CH4) when expressed per year. Male animals produced more gas than females with values of 17.40L/day; 12.46 g/kg DMI and 0.126g/day vs. 15.47L/day, 12.28 g/kg DMI, and 0.0109g/day, respectively. Forage legumes had no significant effects (P > 0.05) on serum total proteins (TP), globulin, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and gamma- glutamyl transferase (GGT) concentrations, but serum concentration of albumin was influenced by the diets (P < 0.05). Sex of animals significantly influenced ALP concentration (P < 0.05) with male animals exhibiting higer ALP values than females. Measured over time, the plasma concentration of urea and ALP significantly increased (P < 0.05) while creatinine and cholesterol concentration decreased (P < 0.05). Although the overall serum concentration of urea, total proteins, globulin, creatinine, ALT, ALP and GGT remained unchanged among the treatments and between sexes; treatment by sex, treatment by day and sex by day interactions were significant (P < 0.05). The white blood cell (WBC), red blood cell (RBC), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), haemoglobin, haematocrite, platelet and mean platelet volume (MPV) levels were similar among treatments and between sexes (P > 0.05). The WBC decreased with time by 8.07 x10 9/l while mean crepuscular volume (MCV) increased by 11.83(fl) from day 15 to day 55. Treatment diets significantly (P < 0.05) influenced neutrophile (percent) content while sex influenced basophile (percent) content. There were no treatment or sex effects (P > 0.05) on lymphocytes (percent), monocytes (percent) and eosinophiles (percent). In the meat quality study, the dietary treatments and sex had a significant (P < 0.05) effect on dressing out percent (DPpercent), initial pH, redness (a*), yellowness (b*), Warner Blartze Shear force (WBS) , drip loss and cooking loss in the chevon from Xhosa goats. Compared with a commercial pellet diet, Lablab and Cowpea diets resulted in similar slaughter body weights (SBW), hot carcass weight (HCW) and cold dressed mass (CDM) of carcasses. However, female animals exhibited a significantly (P < 0.05) higher DPpercent than male animals (42.3percent vs. 38.9percent) for all treatments. The male animals exhibited significantly (P < 0.05) higher pH values one hour after slaughter than females (5.79 vs 5.67). Neverthreless the diet and gender did not significantly (P > 0.05) affect the ultimate pH (pHu). Meat samples from male animals had significantly (P < 0.05) higher redness values than females. Feeding cowpea significantly (P < 0.05) increased meat redness with the least drip loss of chevon. Female animals produced significantly (P < 0.05) tougher chevon compared to male animals; 4.16kg and 3.36kg for female and male, respectively. Lablab and Cowpea posses high CP levels and moderately lower NDF with high ADF values that influences dry matter intake (DMI), digestibility and growth of goats. These forage legumes meet animal requirements for fat, ADF, NDF, CP, Ca, Mn, zinc and Cu and their biomass yield is satisfactory.
- Full Text:
- Date Issued: 2017
Direct and indirect effects of zooplanktivorous predators on the estuarine plankton community
- Authors: Wasserman, Ryan John
- Date: 2014
- Subjects: Zooplankton -- Effect of predation on , Predation (Biology) , Zooplankton -- Predators of , Copepoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5870 , http://hdl.handle.net/10962/d1012938
- Description: Although predation has been identified as a potentially important driver in terrestrial and freshwater ecosystems, estuarine planktonic research has focused largely on the so-called "bottom-up" drivers of community assemblages. As such, this thesis focuses on the direct and indirect effects of zooplanktivorous predators on the planktonic community in an estuarine environment. By using a suite of in situ mesocosm experiments, a number of hypotheses, pertaining to the major research themes associated with predator-prey interactions, are tested. These themes included trophic cascading, risk effects associated with predation events and the importance of predator diversity in maintaining prey communities. The first experiment assessed the significance of apex predation pressure for the planktonic community through trophic cascades. Various treatments using in situ mesocosms were established in a closed oligotrophic estuary to highlight the importance of predation in stabilising estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, varied trophic scenarios were established. The experimental treatment containing apex zooplanktivores had consequences for multiple trophic levels, exerting a stabilising pressure throughout the food web (Chapter 3). Furthermore, pyrosequencing of filtered water samples revealed that when compared to the remaining treatments, the treatment containing stable apex predatory pressure experienced limited temporal deviation-from-initial in bacterial community structure (Chapter 4). These findings are consistent with trophic cascade theory whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity. To assess the non-consumptive effects of predators on prey, two experiments were conducted. Firstly, using egg numbers per clutch as a measure of potential reproductive output, the non-lethal effects of predatory pressure on reproductive success in a key planktonic copepod was investigated. In this study, the average clutch size of fecund female copepods was found to be consistently lower in the presence of predators when compared to females not exposed to predation threat (Chapter 5). The second study assessed the effects of conspecific chemical alarm cues associated with predation, on population dynamics of a copepod species. This study revealed that the copepods appear to detect the presence of chemical alarm cues associated with predation events, with repercussions for population demographics over time. Furthermore, it showed that in the absence of actual predation, copepod prey responses to alarm cues were adjusted over time, consistent with the threat sensitive predator avoidance hypothesis (Chapter 6). The final data chapter dealt with predator diversity and its implications for zooplankton community structure. By experimentally monitoring the effects of two alternate model predators on the metazoan community over time, dissimilarities in community level control emerged. Alternate key prey populations were regulated by the different model predators, highlighting the importance of predator and prey behaviour in mediating predator-prey interactions (Chapter 7). These results highlight the potential importance of predators in maintaining community dynamics in estuarine planktonic communities under certain conditions. This study represents some of the first work to address these various aspects of predator-prey dynamics within the context of planktonic estuarine ecology.
- Full Text:
- Date Issued: 2014
- Authors: Wasserman, Ryan John
- Date: 2014
- Subjects: Zooplankton -- Effect of predation on , Predation (Biology) , Zooplankton -- Predators of , Copepoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5870 , http://hdl.handle.net/10962/d1012938
- Description: Although predation has been identified as a potentially important driver in terrestrial and freshwater ecosystems, estuarine planktonic research has focused largely on the so-called "bottom-up" drivers of community assemblages. As such, this thesis focuses on the direct and indirect effects of zooplanktivorous predators on the planktonic community in an estuarine environment. By using a suite of in situ mesocosm experiments, a number of hypotheses, pertaining to the major research themes associated with predator-prey interactions, are tested. These themes included trophic cascading, risk effects associated with predation events and the importance of predator diversity in maintaining prey communities. The first experiment assessed the significance of apex predation pressure for the planktonic community through trophic cascades. Various treatments using in situ mesocosms were established in a closed oligotrophic estuary to highlight the importance of predation in stabilising estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, varied trophic scenarios were established. The experimental treatment containing apex zooplanktivores had consequences for multiple trophic levels, exerting a stabilising pressure throughout the food web (Chapter 3). Furthermore, pyrosequencing of filtered water samples revealed that when compared to the remaining treatments, the treatment containing stable apex predatory pressure experienced limited temporal deviation-from-initial in bacterial community structure (Chapter 4). These findings are consistent with trophic cascade theory whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity. To assess the non-consumptive effects of predators on prey, two experiments were conducted. Firstly, using egg numbers per clutch as a measure of potential reproductive output, the non-lethal effects of predatory pressure on reproductive success in a key planktonic copepod was investigated. In this study, the average clutch size of fecund female copepods was found to be consistently lower in the presence of predators when compared to females not exposed to predation threat (Chapter 5). The second study assessed the effects of conspecific chemical alarm cues associated with predation, on population dynamics of a copepod species. This study revealed that the copepods appear to detect the presence of chemical alarm cues associated with predation events, with repercussions for population demographics over time. Furthermore, it showed that in the absence of actual predation, copepod prey responses to alarm cues were adjusted over time, consistent with the threat sensitive predator avoidance hypothesis (Chapter 6). The final data chapter dealt with predator diversity and its implications for zooplankton community structure. By experimentally monitoring the effects of two alternate model predators on the metazoan community over time, dissimilarities in community level control emerged. Alternate key prey populations were regulated by the different model predators, highlighting the importance of predator and prey behaviour in mediating predator-prey interactions (Chapter 7). These results highlight the potential importance of predators in maintaining community dynamics in estuarine planktonic communities under certain conditions. This study represents some of the first work to address these various aspects of predator-prey dynamics within the context of planktonic estuarine ecology.
- Full Text:
- Date Issued: 2014
Compensation for distribution of timing and reference signals over optical fibre networks for telescope arrays
- Authors: Wassin, Shukree
- Date: 2018
- Subjects: Fiber optics , Optical communications Very large array telescopes Optical fiber detectors
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/36425 , vital:33941
- Description: Significant advancements and developments have been made in optical frequency standards, in recent years. In order to verify the accuracy and preciseness of the disseminated RF signal, it is essential to compare its stability with the standards provided in literature as well as by metrology institutes. However, conventional frequency comparison techniques via satellites have extremely inferior stability qualities. As a result, the need for an alternative ultra-high precision RF transfer method presented itself. Highly accurate and precise frequency dissemination across optical fiber has proved a leading contender and a possible solution. When compared to conventional data transfer media, optical fiber has proven to be more superior and yields lower transmission errors and is immune to radio frequency interference. A further quality of optical fibre is that its transmission distance can be extended to greater degree than the traditional coaxial cable due to its low loss property. This thesis deals with the compensation of phase noise in single mode optical fibre. Phase noise degrades the performance and stability of the RF signal as well as the optical carrier frequency across long-haul optical networks. This work begins by experimentally demonstrating a unique and novel way for measuring the round-trip optical fibre latency times. The technique is based on all optical wavelength conversion using a stable PPS injection signal. The result highlighted the importance for active phase error compensation along a fibre link. Various computer simulations were used to study the influence of temperature fluctuation on the optical fibre. The first ever error signals generated at NMU was experimentally demonstrated. Results illustrated that, by minimizing the error voltage the phase difference between the transmitted and reference signals were reduced to zero. Performance analysis testing of the VCSEL phase correction actuator showed that majority of the dither iterations that induced the phase compensation took approximately 0.15 s. Residual frequency instabilities of 3.39791 x 10-12 at 1 s and 8.14848 x 10-12 at 103 s was measured when the 26 km G.655 fibre link was running freely. Experimental results further showed that the relative frequency stabilities measured at 1 s and 103 s were 4.43902 x 10-12 and 1.62055 x 10-13 during active compensation, respectively. The novel work presented in this thesis is exciting since the VCSEL is used as the optical source as well as the phase correction actuator. The benefits of such a device is that is reduces system costs and complexities.
- Full Text:
- Date Issued: 2018
- Authors: Wassin, Shukree
- Date: 2018
- Subjects: Fiber optics , Optical communications Very large array telescopes Optical fiber detectors
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/36425 , vital:33941
- Description: Significant advancements and developments have been made in optical frequency standards, in recent years. In order to verify the accuracy and preciseness of the disseminated RF signal, it is essential to compare its stability with the standards provided in literature as well as by metrology institutes. However, conventional frequency comparison techniques via satellites have extremely inferior stability qualities. As a result, the need for an alternative ultra-high precision RF transfer method presented itself. Highly accurate and precise frequency dissemination across optical fiber has proved a leading contender and a possible solution. When compared to conventional data transfer media, optical fiber has proven to be more superior and yields lower transmission errors and is immune to radio frequency interference. A further quality of optical fibre is that its transmission distance can be extended to greater degree than the traditional coaxial cable due to its low loss property. This thesis deals with the compensation of phase noise in single mode optical fibre. Phase noise degrades the performance and stability of the RF signal as well as the optical carrier frequency across long-haul optical networks. This work begins by experimentally demonstrating a unique and novel way for measuring the round-trip optical fibre latency times. The technique is based on all optical wavelength conversion using a stable PPS injection signal. The result highlighted the importance for active phase error compensation along a fibre link. Various computer simulations were used to study the influence of temperature fluctuation on the optical fibre. The first ever error signals generated at NMU was experimentally demonstrated. Results illustrated that, by minimizing the error voltage the phase difference between the transmitted and reference signals were reduced to zero. Performance analysis testing of the VCSEL phase correction actuator showed that majority of the dither iterations that induced the phase compensation took approximately 0.15 s. Residual frequency instabilities of 3.39791 x 10-12 at 1 s and 8.14848 x 10-12 at 103 s was measured when the 26 km G.655 fibre link was running freely. Experimental results further showed that the relative frequency stabilities measured at 1 s and 103 s were 4.43902 x 10-12 and 1.62055 x 10-13 during active compensation, respectively. The novel work presented in this thesis is exciting since the VCSEL is used as the optical source as well as the phase correction actuator. The benefits of such a device is that is reduces system costs and complexities.
- Full Text:
- Date Issued: 2018
The economic and ecological trade-offs of wetland conversion for development projects: the case of the Kampala–Mukono corridor
- Authors: Wasswa, Hannington
- Date: 2018
- Subjects: Wetland ecology -- Uganda -- Kampala , Wetlands -- Uganda -- Kampala Wetland management -- Uganda -- Kampala Hydrogeology
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/36409 , vital:33939
- Description: Wetland diminution for development projects (DPs) in the Kampala–Mukono Corridor (KMC) continues to pose threats to the socio-economic and ecological benefits of wetlands because decision-makers and wetland users at various levels often have insufficient knowledge of these benefits. This situation has resulted in unsustainable development decisions that accord little weight to wetlands and have allocated many of them to DPs. In order to inform decision making for optimal development in the KMC, the present study analysed the spatial and temporal wetland loss to DPs, estimated the economic value of the KMC wetlands, and assessed the environmental consequences of wetland conversion for DPs. Sets of ortho-rectified and cloud-free multi-temporal Landsat MSS (1974) and Landsat TM/ETM+ images (30m) for 1986, 2006, and 2013 were analysed in a spatial and temporal framework. The 79m Landsat image (MSS) of 1974 was resampled and later filtered with subsequent 30m images using a majority filter method. An unsupervised classification approach was employed to characterize the wetlands and associated DPs. The classified DPs and wetland cover types were validated by reference to topographical maps (sheets) of 1974 at a scale of 1:50,000 obtained from Uganda Lands and Surveys, apriori knowledge and Google earth images corresponding to the same spatial and temporal frames. The IDRISI Selva-based Markov Chain model was employed to model future wetland loss to DPs. The Total Economic Valuation Approach (TEV) was employed to quantify selected use values of wetland economic benefits using the market price, replacement cost and contingent valuation techniques. The ecological implications of wetland loss focused on soil organic carbon (SOC) and hydrological impacts in the KMC wetlands. The estimated SOC was assessed with climatic data in order to infer the implication of SOC loss for local climate variability. The manual wet chemistry/oxidation method by Walkley-Black (1934) was adopted to estimate SOC in various wetland cover types. Hydrological impact assessments focused on water quality analysis in various wetland cover types, with major parameters being total nitrogen (TN), total phosphorous (TP) total dissolved solids – (TDS) and total suspended sediments (TSS). Hydrologic flow data parameters across the different wetland cover types in the KMC focused on water level, speed, stream width, and bed load. Results from analysis of the spatial-temporal wetland change revealed that by 2013 the KMC wetlands had lost almost half (47%) of their 1974 areal coverage, with 56% of this loss resulting from conversion to DPs. It is projected that 26% of the KMC wetlands will be lost to more DPs by 2040. Wetland loss is attributed to intensified economic activity and preference of Kampala as an industrial zone, weakness in the previous spatial planning of Kampala, and the general lack of information flow to various institutions involved in the establishment of DPs. The KMC wetlands provide a flow of economic benefits at a minimum approximated value of US$ 3,418 / ha / per year. It is revealed that a great deal of these economic benefits (88%) accrues to the local subsistence level in the form of livelihood products, incomes, and employment benefits. The 56% wetlands loss to DPs in the KMC by 2013 brings the minimum economic value lost to US$ 19,311,700 in the sampled wetlands, and projections of future wetland loss put the minimum economic loss at US$ 48,368,118 by 2040. Continuous degradation of these wetlands means serious economic costs to the government and local communities, as reflected in high replacement expenditures for wetland services, foregone incomes, subsistence livelihood support and alternative employment. The highest carbon (C) sinks were identified in forest swamps, palms, thickets and wetlands converted to agriculture, which accounted for 25% of the KMC wetlands by 2013, while the lowest total soil organic carbon (TSOC) range occurred in converted wetland cover types (converted wetlands to industrial and settlements) that occupied 47% of the study area. A general decrease in SOC sequestration from 1974 to 2013 across the KMC wetlands is identified, with the lowest C pool registered in 2013. The dwindling SOC banks are considered to be partly responsible for varying climate and related feedbacks on wetland benefits in the KMC. The hydrologic impacts of wetland loss are felt mainly in converted wetland cover types, in the form of compromised water quality, with increased nutrient pollution and TSS. These all create negative impacts on wetland hydrological services, particularly filtration, flood attenuation, recharge and discharge benefits, all of which have profound effects on biodiversity. There is an urgent need to reduce the scale of wetland diminution in the KMC. This will be achieved if mitigation and conservation measures are undertaken. Mitigation measures should include a revision of development plans, user sensitization on wetland economic values and enforcement of regulatory mechanisms. Conservation strategies should involve the use of economic incentives and disincentives which include: a revision of historic property rights to regulate wetland use, performance bonds or subsidies for environmentally friendly activities and taxes, fees or fines for unacceptable levels of degradation and tradable permits that utilise the concept of ‘wetland banks’ to ensure no further loss of the KMC wetlands to DPs. Future research should focus on modelling the response of wetland ecosystems to multiple threats and management interventions, and on a feasibility study of wetland restoration options and the implications for local people’s livelihoods in the KMC.
- Full Text:
- Date Issued: 2018
- Authors: Wasswa, Hannington
- Date: 2018
- Subjects: Wetland ecology -- Uganda -- Kampala , Wetlands -- Uganda -- Kampala Wetland management -- Uganda -- Kampala Hydrogeology
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/36409 , vital:33939
- Description: Wetland diminution for development projects (DPs) in the Kampala–Mukono Corridor (KMC) continues to pose threats to the socio-economic and ecological benefits of wetlands because decision-makers and wetland users at various levels often have insufficient knowledge of these benefits. This situation has resulted in unsustainable development decisions that accord little weight to wetlands and have allocated many of them to DPs. In order to inform decision making for optimal development in the KMC, the present study analysed the spatial and temporal wetland loss to DPs, estimated the economic value of the KMC wetlands, and assessed the environmental consequences of wetland conversion for DPs. Sets of ortho-rectified and cloud-free multi-temporal Landsat MSS (1974) and Landsat TM/ETM+ images (30m) for 1986, 2006, and 2013 were analysed in a spatial and temporal framework. The 79m Landsat image (MSS) of 1974 was resampled and later filtered with subsequent 30m images using a majority filter method. An unsupervised classification approach was employed to characterize the wetlands and associated DPs. The classified DPs and wetland cover types were validated by reference to topographical maps (sheets) of 1974 at a scale of 1:50,000 obtained from Uganda Lands and Surveys, apriori knowledge and Google earth images corresponding to the same spatial and temporal frames. The IDRISI Selva-based Markov Chain model was employed to model future wetland loss to DPs. The Total Economic Valuation Approach (TEV) was employed to quantify selected use values of wetland economic benefits using the market price, replacement cost and contingent valuation techniques. The ecological implications of wetland loss focused on soil organic carbon (SOC) and hydrological impacts in the KMC wetlands. The estimated SOC was assessed with climatic data in order to infer the implication of SOC loss for local climate variability. The manual wet chemistry/oxidation method by Walkley-Black (1934) was adopted to estimate SOC in various wetland cover types. Hydrological impact assessments focused on water quality analysis in various wetland cover types, with major parameters being total nitrogen (TN), total phosphorous (TP) total dissolved solids – (TDS) and total suspended sediments (TSS). Hydrologic flow data parameters across the different wetland cover types in the KMC focused on water level, speed, stream width, and bed load. Results from analysis of the spatial-temporal wetland change revealed that by 2013 the KMC wetlands had lost almost half (47%) of their 1974 areal coverage, with 56% of this loss resulting from conversion to DPs. It is projected that 26% of the KMC wetlands will be lost to more DPs by 2040. Wetland loss is attributed to intensified economic activity and preference of Kampala as an industrial zone, weakness in the previous spatial planning of Kampala, and the general lack of information flow to various institutions involved in the establishment of DPs. The KMC wetlands provide a flow of economic benefits at a minimum approximated value of US$ 3,418 / ha / per year. It is revealed that a great deal of these economic benefits (88%) accrues to the local subsistence level in the form of livelihood products, incomes, and employment benefits. The 56% wetlands loss to DPs in the KMC by 2013 brings the minimum economic value lost to US$ 19,311,700 in the sampled wetlands, and projections of future wetland loss put the minimum economic loss at US$ 48,368,118 by 2040. Continuous degradation of these wetlands means serious economic costs to the government and local communities, as reflected in high replacement expenditures for wetland services, foregone incomes, subsistence livelihood support and alternative employment. The highest carbon (C) sinks were identified in forest swamps, palms, thickets and wetlands converted to agriculture, which accounted for 25% of the KMC wetlands by 2013, while the lowest total soil organic carbon (TSOC) range occurred in converted wetland cover types (converted wetlands to industrial and settlements) that occupied 47% of the study area. A general decrease in SOC sequestration from 1974 to 2013 across the KMC wetlands is identified, with the lowest C pool registered in 2013. The dwindling SOC banks are considered to be partly responsible for varying climate and related feedbacks on wetland benefits in the KMC. The hydrologic impacts of wetland loss are felt mainly in converted wetland cover types, in the form of compromised water quality, with increased nutrient pollution and TSS. These all create negative impacts on wetland hydrological services, particularly filtration, flood attenuation, recharge and discharge benefits, all of which have profound effects on biodiversity. There is an urgent need to reduce the scale of wetland diminution in the KMC. This will be achieved if mitigation and conservation measures are undertaken. Mitigation measures should include a revision of development plans, user sensitization on wetland economic values and enforcement of regulatory mechanisms. Conservation strategies should involve the use of economic incentives and disincentives which include: a revision of historic property rights to regulate wetland use, performance bonds or subsidies for environmentally friendly activities and taxes, fees or fines for unacceptable levels of degradation and tradable permits that utilise the concept of ‘wetland banks’ to ensure no further loss of the KMC wetlands to DPs. Future research should focus on modelling the response of wetland ecosystems to multiple threats and management interventions, and on a feasibility study of wetland restoration options and the implications for local people’s livelihoods in the KMC.
- Full Text:
- Date Issued: 2018
Compensation for polarization mode dispersion and nonlinear birefringence in a multichannel optical fibre system
- Authors: Waswa, David Wafula
- Date: 2009
- Subjects: Fiber optics , Nonlinear optics , Polarization (Light)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10375 , http://hdl.handle.net/10948/885 , Fiber optics , Nonlinear optics , Polarization (Light)
- Description: Polarization mode dispersion (PMD) is stochastic in nature and continues evolving in an unpredictable manner according to the changing environment. Nonlinear birefringence in multichannel systems alters the polarization states of the bits, so that they vary from one bit to the next in a way that is difficult to predict. These are the two major signal-impairment effects that are inherent in optical fibre transmission links which can seriously degrade network performance. It is therefore extremely challenging to compensate for both linear and nonlinear birefringence in multichannel systems. The purpose of this thesis is to investigate the interaction between PMD and nonlinear induced birefringence in a fibre with consideration of mode coupling. A sound knowledge of this interaction is necessary in designing a linear and nonlinear polarization mode dispersion compensator for WDM systems, as was successfully carried out in this study. The investigation shows that the effect of nonlinear birefringence alone depolarizes the signal, while in high PMD links where polarization mode coupling is high, the nonlinear birefringence effect couples with second-order PMD such that it may reduce the penalty and improve the signal DOP. Further investigation shows that when nonlinear birefringence becomes significant, asymmetry arises between the two principal axes of the fibre, such that it is only one axis which experiences the effect of nonlinear birefringence. It is found out that along this vii axis, there exists a critical point in pump power where the nonlinear birefringence cancels PMD in the link and improves the signal. An adaptive compensator to cancel PMD and nonlinear birefringence was designed based on feedforward DOP-monitoring signal. The compensator was tested both at laboratory level and on the Telkom buried fibre link and found to be functioning as intended. It was able to adaptively track and compensate PMD in the link in less than a second. The compensator was able to cancel PMD in the link up to a maximum of 30 ps. The compensator improved the DOP of the worst signal by more than 100 percent.
- Full Text:
- Date Issued: 2009
- Authors: Waswa, David Wafula
- Date: 2009
- Subjects: Fiber optics , Nonlinear optics , Polarization (Light)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10375 , http://hdl.handle.net/10948/885 , Fiber optics , Nonlinear optics , Polarization (Light)
- Description: Polarization mode dispersion (PMD) is stochastic in nature and continues evolving in an unpredictable manner according to the changing environment. Nonlinear birefringence in multichannel systems alters the polarization states of the bits, so that they vary from one bit to the next in a way that is difficult to predict. These are the two major signal-impairment effects that are inherent in optical fibre transmission links which can seriously degrade network performance. It is therefore extremely challenging to compensate for both linear and nonlinear birefringence in multichannel systems. The purpose of this thesis is to investigate the interaction between PMD and nonlinear induced birefringence in a fibre with consideration of mode coupling. A sound knowledge of this interaction is necessary in designing a linear and nonlinear polarization mode dispersion compensator for WDM systems, as was successfully carried out in this study. The investigation shows that the effect of nonlinear birefringence alone depolarizes the signal, while in high PMD links where polarization mode coupling is high, the nonlinear birefringence effect couples with second-order PMD such that it may reduce the penalty and improve the signal DOP. Further investigation shows that when nonlinear birefringence becomes significant, asymmetry arises between the two principal axes of the fibre, such that it is only one axis which experiences the effect of nonlinear birefringence. It is found out that along this vii axis, there exists a critical point in pump power where the nonlinear birefringence cancels PMD in the link and improves the signal. An adaptive compensator to cancel PMD and nonlinear birefringence was designed based on feedforward DOP-monitoring signal. The compensator was tested both at laboratory level and on the Telkom buried fibre link and found to be functioning as intended. It was able to adaptively track and compensate PMD in the link in less than a second. The compensator was able to cancel PMD in the link up to a maximum of 30 ps. The compensator improved the DOP of the worst signal by more than 100 percent.
- Full Text:
- Date Issued: 2009
An investigation into the bacterial biosynthetic origins of bioactive natural products isolated from South African latrunculid sponges
- Authors: Waterworth, Samantha Che
- Date: 2018
- Subjects: Marine biodiversity , Metagenomics , Sponges Biotechnology , Spirochetes , Natural products Biotechnology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/61826 , vital:28065
- Description: Several pyrroloiminoquinone alkaloids exhibiting cytotoxic, anti-tumour activity have been isolated from sponges within the Latrunculiidae family that are endemic to the South African coastline. Other, structurally similar pyrroloiminoquinone compounds have been isolated from geographically distant and phylogenetically distinct marine sponges, as well as terrestrial myxomycetes which suggested that sponge-associated bacteria may be the true biosynthetic origin of pyrroloiminoquinone compounds. Previous studies have shown that there is conservation of spirochete and betaproteobacterial species in the bacterial communities associated with South African Latrunculiidae sponges and it was proposed that these conserved bacteria represented candidate pyrroloiminoquinone-producers. This study aimed to confirm the conserved dominance of betaproteobacteria and spirochetes within bacterial communities associated with South African latrunculid sponges and employed a shotgun metagenomic approach to assess the functional and biosynthetic potential of associated microbiota in Tsitsikamma favus sponges. Clustering of assembled contigs revealed twenty-three putative bacterial genomes, of which, two were identified as representatives of the conserved betaproteobacteria and spirochete species previously identified in Tsitsikamma sponges. It was shown that the spirochete was most likely an obligate symbiont that benefitted the host sponge through possible defence against pathogenic bacteria and/or nutrient acquisition. The putative genome representing the conserved betaproteobacteria was found to be heavily contaminated and further sequencing is required to accurately resolve the genome for functional characterization. Several biosynthetic gene clusters were identified and demonstrated the bioactive potential of Tsitsikamma favus-associated bacteria. A biosynthetic gene cluster was identified on an unclustered contig that included several genetic features that were indicative of possible pyrroloiminoquinone production.
- Full Text:
- Date Issued: 2018
- Authors: Waterworth, Samantha Che
- Date: 2018
- Subjects: Marine biodiversity , Metagenomics , Sponges Biotechnology , Spirochetes , Natural products Biotechnology
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/61826 , vital:28065
- Description: Several pyrroloiminoquinone alkaloids exhibiting cytotoxic, anti-tumour activity have been isolated from sponges within the Latrunculiidae family that are endemic to the South African coastline. Other, structurally similar pyrroloiminoquinone compounds have been isolated from geographically distant and phylogenetically distinct marine sponges, as well as terrestrial myxomycetes which suggested that sponge-associated bacteria may be the true biosynthetic origin of pyrroloiminoquinone compounds. Previous studies have shown that there is conservation of spirochete and betaproteobacterial species in the bacterial communities associated with South African Latrunculiidae sponges and it was proposed that these conserved bacteria represented candidate pyrroloiminoquinone-producers. This study aimed to confirm the conserved dominance of betaproteobacteria and spirochetes within bacterial communities associated with South African latrunculid sponges and employed a shotgun metagenomic approach to assess the functional and biosynthetic potential of associated microbiota in Tsitsikamma favus sponges. Clustering of assembled contigs revealed twenty-three putative bacterial genomes, of which, two were identified as representatives of the conserved betaproteobacteria and spirochete species previously identified in Tsitsikamma sponges. It was shown that the spirochete was most likely an obligate symbiont that benefitted the host sponge through possible defence against pathogenic bacteria and/or nutrient acquisition. The putative genome representing the conserved betaproteobacteria was found to be heavily contaminated and further sequencing is required to accurately resolve the genome for functional characterization. Several biosynthetic gene clusters were identified and demonstrated the bioactive potential of Tsitsikamma favus-associated bacteria. A biosynthetic gene cluster was identified on an unclustered contig that included several genetic features that were indicative of possible pyrroloiminoquinone production.
- Full Text:
- Date Issued: 2018
A framework for interpreting noisy, two-dimensional images, based on a fuzzification of programmed, attributed graph grammars
- Authors: Watkins, Gregory Shroll
- Date: 1998
- Subjects: Music -- Data processing Computer sound processing Artificial intelligence -- Musical applications Fuzzy systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4604 , http://hdl.handle.net/10962/d1004862
- Description: This thesis investigates a fuzzy syntactic approach to the interpretation of noisy two-dimensional images. This approach is based on a modification of the attributed graph grammar formalism to utilise fuzzy membership functions in the applicability predicates. As far as we are aware, this represents the first such modification of graph grammars. Furthermore, we develop a method for programming the resultant fuzzy attributed graph grammars through the use of non-deterministic control diagrams. To do this, we modify the standard programming mechanism to allow it to cope with the fuzzy certainty values associated with productions in our grammar. Our objective was to develop a flexible framework which can be used for the recognition of a wide variety of image classes, and which is adept at dealing with noise in these images. Programmed graph grammars are specifically chosen for the ease with which they allow one to specify a new two-dimensional image class. We implement a prototype system for Optical Music Recognition using our framework. This system allows us to test the capabilities of the framework for coping with noise in the context of handwritten music score recognition. Preliminary results from the prototype system show that the framework copes well with noisy images.
- Full Text:
- Date Issued: 1998
- Authors: Watkins, Gregory Shroll
- Date: 1998
- Subjects: Music -- Data processing Computer sound processing Artificial intelligence -- Musical applications Fuzzy systems
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4604 , http://hdl.handle.net/10962/d1004862
- Description: This thesis investigates a fuzzy syntactic approach to the interpretation of noisy two-dimensional images. This approach is based on a modification of the attributed graph grammar formalism to utilise fuzzy membership functions in the applicability predicates. As far as we are aware, this represents the first such modification of graph grammars. Furthermore, we develop a method for programming the resultant fuzzy attributed graph grammars through the use of non-deterministic control diagrams. To do this, we modify the standard programming mechanism to allow it to cope with the fuzzy certainty values associated with productions in our grammar. Our objective was to develop a flexible framework which can be used for the recognition of a wide variety of image classes, and which is adept at dealing with noise in these images. Programmed graph grammars are specifically chosen for the ease with which they allow one to specify a new two-dimensional image class. We implement a prototype system for Optical Music Recognition using our framework. This system allows us to test the capabilities of the framework for coping with noise in the context of handwritten music score recognition. Preliminary results from the prototype system show that the framework copes well with noisy images.
- Full Text:
- Date Issued: 1998