Effect of processing on the efficacy and safety of Solanum Aculeastrum Dunal berries
- Authors: Aboyade, Oluwaseyi Mayode
- Date: 2009
- Subjects: Medicinal plants -- South Africa -- Eastern Cape , Plant extracts , Drugs -- Effectiveness , Berries , Solanum , Solanum Aculeastrum -- Effectiveness
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11302 , http://hdl.handle.net/10353/d1001051 , Medicinal plants -- South Africa -- Eastern Cape , Plant extracts , Drugs -- Effectiveness , Berries , Solanum , Solanum Aculeastrum -- Effectiveness
- Description: General Abstract There has been a steady increase in the use of medicinal plants in the last two decades in both developed and developing countries for prevention, management and treatment of diseases. This increase has been due to reasons such as ease of access, better cultural acceptability and compatibility, cost effectiveness and also the bid to “go natural”. Unfortunately, the notion that herbal medicines are relatively safe because they are natural has led to serious and potentially fatal consequences in phytotherapy. The lack of rigorous research to prove the effectiveness and safety of many medicinal plants is of great concern to the health care system. This thesis therefore addresses not just the efficacy, but also the safety of the extracts of the berry of Solanum aculeastrum - a medicinal plant used, among other things, for the treatment of breast cancer in the Eastern Cape Province of South Africa. Particular attention was paid to the possible effect of different processing methods of the berry extracts on inflammation, cytotoxicity, and toxicity. In studying the comparative effects of various processing methods, four different preparations of the extracts were investigated. These include fresh, dried, boiled fresh, and boiled dried berries. While the effect of processing on the anti-inflammatory properties of the extracts was not dose dependent, the percentage reduction in inflammation was highly significant and more prominent in both concentrations of the boiled fresh berries than the reference drug, indomethacin. Furthermore, the four extracts varied in their ability to act either centrally or peripherally in their effect on pain. Assessment of the analgesic response using the formalin test showed that, at both concentrations tested, none of the extracts inhibited the first phase of the formalin test. Furthermore, it was observed that boiling had differing results on the activity of the iii fresh and dried extracts. While boiling of the dried berries reduced pain in the rats, the opposite trend was observed with the boiled fresh berries. Results of the influence of processing of the berries on cytotoxicity indicated that the extracts are potent inhibitors of human breast, cervical and colonic carcinoma cells and the non-cancerous cells (both the actively dividing and confluent Chang liver cells). Although, in terms of relative potency, the fresh berries appeared to be the most active of the extracts, processing of the berries caused an increase in apoptotic cells and a subsequent decrease in the necrotic cells. The effect of processing on the safety of the berry of S. aculeastrum on the rats fed for 28 days was also investigated. The various doses (1, 10 and 25 mg/kg body weight) of all the four extracts did not alter the activity and the weight of the animals throughout the period of treatment. A reduction in organ to body weight ratio of the heart, kidney, liver and spleen was observed in all the extracts. Regarding the haematological parameters, different patterns of effect were observed between the extracts and within the treated doses. The observed alterations in the biochemical parameters by the various extract of Solanum aculeastrum berries at all the doses may have consequential effects on the normal functioning of these organs. In conclusion, this study has shown that there is some justification for the traditional use of the berries of Solanum aculeastrum in the treatment of inflammation related ailments and cancer. However, the medicinal use of the plant also poses considerable health risks. Investigation conducted into the plant’s safety revealed that the berry extracts were nephrotoxic, hepatotoxic, haematotoxic and at higher doses, fatal. Another concern with regard to the plant’s safety is the non-selectivity of its extracts in the inhibition of carcinoma, actively dividing and un-dividing cells. Assessment of the effect of the processing on the berry’s efficacy and safety as herbal iv remedy produced mixed results. On the one hand, processing seemed to improve the extract’s anti-inflammatory and analgesic activity, while reducing its cytotoxic potential. On the other hand, a reduction in the toxicity was observed on the processed extracts compared to the fresh ones. This may be an indication that processing has an overall beneficial effect on the medicinal properties of the plant and should thus be considered as a method of making the berries of Solanum aculeastrum safer for use as a herbal remedy.
- Full Text:
- Date Issued: 2009
- Authors: Aboyade, Oluwaseyi Mayode
- Date: 2009
- Subjects: Medicinal plants -- South Africa -- Eastern Cape , Plant extracts , Drugs -- Effectiveness , Berries , Solanum , Solanum Aculeastrum -- Effectiveness
- Language: English
- Type: Thesis , Doctoral , PhD (Botany)
- Identifier: vital:11302 , http://hdl.handle.net/10353/d1001051 , Medicinal plants -- South Africa -- Eastern Cape , Plant extracts , Drugs -- Effectiveness , Berries , Solanum , Solanum Aculeastrum -- Effectiveness
- Description: General Abstract There has been a steady increase in the use of medicinal plants in the last two decades in both developed and developing countries for prevention, management and treatment of diseases. This increase has been due to reasons such as ease of access, better cultural acceptability and compatibility, cost effectiveness and also the bid to “go natural”. Unfortunately, the notion that herbal medicines are relatively safe because they are natural has led to serious and potentially fatal consequences in phytotherapy. The lack of rigorous research to prove the effectiveness and safety of many medicinal plants is of great concern to the health care system. This thesis therefore addresses not just the efficacy, but also the safety of the extracts of the berry of Solanum aculeastrum - a medicinal plant used, among other things, for the treatment of breast cancer in the Eastern Cape Province of South Africa. Particular attention was paid to the possible effect of different processing methods of the berry extracts on inflammation, cytotoxicity, and toxicity. In studying the comparative effects of various processing methods, four different preparations of the extracts were investigated. These include fresh, dried, boiled fresh, and boiled dried berries. While the effect of processing on the anti-inflammatory properties of the extracts was not dose dependent, the percentage reduction in inflammation was highly significant and more prominent in both concentrations of the boiled fresh berries than the reference drug, indomethacin. Furthermore, the four extracts varied in their ability to act either centrally or peripherally in their effect on pain. Assessment of the analgesic response using the formalin test showed that, at both concentrations tested, none of the extracts inhibited the first phase of the formalin test. Furthermore, it was observed that boiling had differing results on the activity of the iii fresh and dried extracts. While boiling of the dried berries reduced pain in the rats, the opposite trend was observed with the boiled fresh berries. Results of the influence of processing of the berries on cytotoxicity indicated that the extracts are potent inhibitors of human breast, cervical and colonic carcinoma cells and the non-cancerous cells (both the actively dividing and confluent Chang liver cells). Although, in terms of relative potency, the fresh berries appeared to be the most active of the extracts, processing of the berries caused an increase in apoptotic cells and a subsequent decrease in the necrotic cells. The effect of processing on the safety of the berry of S. aculeastrum on the rats fed for 28 days was also investigated. The various doses (1, 10 and 25 mg/kg body weight) of all the four extracts did not alter the activity and the weight of the animals throughout the period of treatment. A reduction in organ to body weight ratio of the heart, kidney, liver and spleen was observed in all the extracts. Regarding the haematological parameters, different patterns of effect were observed between the extracts and within the treated doses. The observed alterations in the biochemical parameters by the various extract of Solanum aculeastrum berries at all the doses may have consequential effects on the normal functioning of these organs. In conclusion, this study has shown that there is some justification for the traditional use of the berries of Solanum aculeastrum in the treatment of inflammation related ailments and cancer. However, the medicinal use of the plant also poses considerable health risks. Investigation conducted into the plant’s safety revealed that the berry extracts were nephrotoxic, hepatotoxic, haematotoxic and at higher doses, fatal. Another concern with regard to the plant’s safety is the non-selectivity of its extracts in the inhibition of carcinoma, actively dividing and un-dividing cells. Assessment of the effect of the processing on the berry’s efficacy and safety as herbal iv remedy produced mixed results. On the one hand, processing seemed to improve the extract’s anti-inflammatory and analgesic activity, while reducing its cytotoxic potential. On the other hand, a reduction in the toxicity was observed on the processed extracts compared to the fresh ones. This may be an indication that processing has an overall beneficial effect on the medicinal properties of the plant and should thus be considered as a method of making the berries of Solanum aculeastrum safer for use as a herbal remedy.
- Full Text:
- Date Issued: 2009
The coordination chemistry of Rhenium(V) with multidentate no-donor ligands
- Authors: Abrahams, Abubak'r
- Date: 2009
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10370 , http://hdl.handle.net/10948/912 , Rhenium , Ligands
- Description: The neutral distorted octahedral complexes [ReOCl(L)] {H2L = N,N-bis(2- hydroxybenzyl)-2-(2-aminoethyl)dimethylamine (H2had), N,N-bis(2-hydroxybenzyl) aminomethylpyridine (H2hap); N,N-bis(2-hydroxybenzyl)-2-(2-aminoethyl)pyridine (H2hae)} were prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H2L in ethanol. The X-ray structure determinations of [ReOCl(had)] and [ReOCl(hap)] were performed, and in both complexes the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen. Treatment of trans-[ReO2(py)4]I with two equivalents and one equivalent each of H2had in acetone afforded the iodide salts of the oxypyridinium-ammonium zwitterions N1-(2-hydroxybenzyl)-N2,N2- dimethyl-N1-((2-oxypyridinium)-1-methyl)ethane-1,2-diamine [Hhpd]+ and N2,N2- dimethyl-N1-bis((2-oxypyridinium)-1-methyl)ethane-1,2-diamine [dod]+ respectively. In [Hhpd]I, one of the 2-hydroxyphenyl groups of H2had is substituted by an oxypyridinium group, and in [dod]I, both 2-hydroxyphenyl groups are converted. The X-ray crystal structure determination of the starting material H2had, [Hhpd]I and [dod]I reveals trigonal pyramidal geometries around the central amino nitrogen. The complex salt [ReO(bsa)]PF6 (H2bsa=bis(N-methylsalicylicylideneiminopropyl) amine) was prepared from the reaction of cis-[ReO2I(PPh3)2] with H2bsa in toluene. The dianionic pentadentate ligand bsa is coordinated to the ReO3+ moiety via one secondary amino and two imino nitrogens, and two anionic phenolate oxygens. The complex was characterized by spectroscopy and analytical data, and the structure has been determined by single-crystal X-ray diffraction analysis. The complex exhibits a distorted octahedral geometry around the central rhenium(V) ion, with the basal plane being defined by a phenolate oxygen, two imino nitrogens and the secondary amino. ix A. Abrahams Nelson Mandela Metropolitan University The reaction of a two-fold molar excess of the potentially NN-donor ligand 2,2’- dipyridylamine (dpa) with trans-[ReO(OEt)Cl2(PPh3)2] in ethanol led to the isolation of [ReOCl2(OEt)(dpa)]. The X-ray crystal structure shows that the NN-chelated dpa is coordinated in the equatorial plane cis to the oxo and ethoxo groups, which are in trans positions relative to each other. The treatment of trans- [ReOCl3(PPh3)2] with a tenfold molar excess of dpa in ethanol at the refluxing temperature yielded the trans-dioxo complex [ReO2(dpa)2]Cl, but with a twofold molar excess only (μ-O)[{ReOCl2(dpa)}2] was isolated. Repeating the latter reaction with (n-Bu4N)[ReOCl4] as starting material in ethanol at room temperature a dark green product, also with the formulation (μ-O)[{ReOCl2(dpa)}2], was isolated. The reaction of equimolar quantities of bis(pyridin-2-yl)methyl)amine (HBPA) with (n-Bu4N)[ReOCl4] in acetone at room temperature led to the isolation of the sixcoordinate rhenium(V) complex [ReOCl(H2O)(BPA)]Cl. IR, NMR and X-ray crystallographic results indicate that BPA is coordinated as a tridentate uninegative chelate, with deprotonation of the amine nitrogen. The water molecule is coordinated trans to the oxo group, with the Re=O and Re-OH2 bond distances equal to 1.663(9) and 2.21(1) Å respectively. Complexes of the general formula [ReOX2{(C5H4N)CH(O)CH2(C5H4N)}] (X = Cl, I) were prepared by the reactions of trans-[ReOCl3(PPh3)2] and trans- [ReOI2(OEt)(PPh3)2] with cis-1,2-di-(2-pyridyl)ethylene (DPE) in ethanol and benzene in air. Experimental evidence shows that the coordinated DPE ligand has undergone addition of water at the ethylenic carbons, and that the (C5H4N)CH(O)CH2(C5H4N) moiety acts as a uninegative tridentate NON-donor ligand. The X-ray crystal structures of both complexes show a distorted octahedral geometry around the rhenium(V) centre. The treatment of trans-[ReOCl3(PPh3)2] with H2dbd in a 2:1 molar ratio in acetonitrile led to the isolation of the ligand-bridged dimer (μ-dbd)[ReOCl2(PPh3)]2. The X-ray crystal structure of the complex reveals a dinuclear structure in which two rhenium(V) ions are bridged by the dbd ligand. Each rhenium ion is in a x A. Abrahams Nelson Mandela Metropolitan University distorted octahedral geometry. The basal plane is defined by a phosphorus atom of the PPh3 group, two chlorides cis to each other, and a pyridyl nitrogen atom of dbd. The oxo group and alcoholate oxygen of dbd lie in trans axial positions. The complexes cis-[ReOX2(msa)(PPh3)] (X = Cl, Br, I) were prepared from trans- [ReOCl3(PPh3)2], trans-[ReOBr3(PPh3)2] or trans-[ReOI2(OEt)(PPh3)2] with 2-(1- iminoethyl)phenol (Hmsa) in acetonitrile. An X-ray crystallographic study shows that the bonding distances and angles in the comlexes are nearly identical, and that the two halides in each complex are coordinated cis to each other in the equatorial plane cis to the oxo group. The oxo-bridged dinuclear rhenium(V) complex [(μ-O){ReOCl(amp)}2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] and 6-amino-3-methyl-1-phenyl- 4-azahept-2-ene-1-one (Hamp) in acetone. The characterization of the complex by elemental analysis, infrared and 1H NMR spectroscopy and X-ray crystallography shows that amp is coordinated as a monoanionic NNO-donor chelate as an amino-amido ketone. However, the reaction of the similar ligand 7- amino-4,7-dimethyl-5-aza-3-octen-2-one (Hada) with [Re(CO)5Br] produced the product fac-[Re(CO)3Br(Hada)], with Hada coordinated as a neutral NN-donor amino-imino-ketone.
- Full Text:
- Date Issued: 2009
- Authors: Abrahams, Abubak'r
- Date: 2009
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10370 , http://hdl.handle.net/10948/912 , Rhenium , Ligands
- Description: The neutral distorted octahedral complexes [ReOCl(L)] {H2L = N,N-bis(2- hydroxybenzyl)-2-(2-aminoethyl)dimethylamine (H2had), N,N-bis(2-hydroxybenzyl) aminomethylpyridine (H2hap); N,N-bis(2-hydroxybenzyl)-2-(2-aminoethyl)pyridine (H2hae)} were prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H2L in ethanol. The X-ray structure determinations of [ReOCl(had)] and [ReOCl(hap)] were performed, and in both complexes the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen. Treatment of trans-[ReO2(py)4]I with two equivalents and one equivalent each of H2had in acetone afforded the iodide salts of the oxypyridinium-ammonium zwitterions N1-(2-hydroxybenzyl)-N2,N2- dimethyl-N1-((2-oxypyridinium)-1-methyl)ethane-1,2-diamine [Hhpd]+ and N2,N2- dimethyl-N1-bis((2-oxypyridinium)-1-methyl)ethane-1,2-diamine [dod]+ respectively. In [Hhpd]I, one of the 2-hydroxyphenyl groups of H2had is substituted by an oxypyridinium group, and in [dod]I, both 2-hydroxyphenyl groups are converted. The X-ray crystal structure determination of the starting material H2had, [Hhpd]I and [dod]I reveals trigonal pyramidal geometries around the central amino nitrogen. The complex salt [ReO(bsa)]PF6 (H2bsa=bis(N-methylsalicylicylideneiminopropyl) amine) was prepared from the reaction of cis-[ReO2I(PPh3)2] with H2bsa in toluene. The dianionic pentadentate ligand bsa is coordinated to the ReO3+ moiety via one secondary amino and two imino nitrogens, and two anionic phenolate oxygens. The complex was characterized by spectroscopy and analytical data, and the structure has been determined by single-crystal X-ray diffraction analysis. The complex exhibits a distorted octahedral geometry around the central rhenium(V) ion, with the basal plane being defined by a phenolate oxygen, two imino nitrogens and the secondary amino. ix A. Abrahams Nelson Mandela Metropolitan University The reaction of a two-fold molar excess of the potentially NN-donor ligand 2,2’- dipyridylamine (dpa) with trans-[ReO(OEt)Cl2(PPh3)2] in ethanol led to the isolation of [ReOCl2(OEt)(dpa)]. The X-ray crystal structure shows that the NN-chelated dpa is coordinated in the equatorial plane cis to the oxo and ethoxo groups, which are in trans positions relative to each other. The treatment of trans- [ReOCl3(PPh3)2] with a tenfold molar excess of dpa in ethanol at the refluxing temperature yielded the trans-dioxo complex [ReO2(dpa)2]Cl, but with a twofold molar excess only (μ-O)[{ReOCl2(dpa)}2] was isolated. Repeating the latter reaction with (n-Bu4N)[ReOCl4] as starting material in ethanol at room temperature a dark green product, also with the formulation (μ-O)[{ReOCl2(dpa)}2], was isolated. The reaction of equimolar quantities of bis(pyridin-2-yl)methyl)amine (HBPA) with (n-Bu4N)[ReOCl4] in acetone at room temperature led to the isolation of the sixcoordinate rhenium(V) complex [ReOCl(H2O)(BPA)]Cl. IR, NMR and X-ray crystallographic results indicate that BPA is coordinated as a tridentate uninegative chelate, with deprotonation of the amine nitrogen. The water molecule is coordinated trans to the oxo group, with the Re=O and Re-OH2 bond distances equal to 1.663(9) and 2.21(1) Å respectively. Complexes of the general formula [ReOX2{(C5H4N)CH(O)CH2(C5H4N)}] (X = Cl, I) were prepared by the reactions of trans-[ReOCl3(PPh3)2] and trans- [ReOI2(OEt)(PPh3)2] with cis-1,2-di-(2-pyridyl)ethylene (DPE) in ethanol and benzene in air. Experimental evidence shows that the coordinated DPE ligand has undergone addition of water at the ethylenic carbons, and that the (C5H4N)CH(O)CH2(C5H4N) moiety acts as a uninegative tridentate NON-donor ligand. The X-ray crystal structures of both complexes show a distorted octahedral geometry around the rhenium(V) centre. The treatment of trans-[ReOCl3(PPh3)2] with H2dbd in a 2:1 molar ratio in acetonitrile led to the isolation of the ligand-bridged dimer (μ-dbd)[ReOCl2(PPh3)]2. The X-ray crystal structure of the complex reveals a dinuclear structure in which two rhenium(V) ions are bridged by the dbd ligand. Each rhenium ion is in a x A. Abrahams Nelson Mandela Metropolitan University distorted octahedral geometry. The basal plane is defined by a phosphorus atom of the PPh3 group, two chlorides cis to each other, and a pyridyl nitrogen atom of dbd. The oxo group and alcoholate oxygen of dbd lie in trans axial positions. The complexes cis-[ReOX2(msa)(PPh3)] (X = Cl, Br, I) were prepared from trans- [ReOCl3(PPh3)2], trans-[ReOBr3(PPh3)2] or trans-[ReOI2(OEt)(PPh3)2] with 2-(1- iminoethyl)phenol (Hmsa) in acetonitrile. An X-ray crystallographic study shows that the bonding distances and angles in the comlexes are nearly identical, and that the two halides in each complex are coordinated cis to each other in the equatorial plane cis to the oxo group. The oxo-bridged dinuclear rhenium(V) complex [(μ-O){ReOCl(amp)}2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] and 6-amino-3-methyl-1-phenyl- 4-azahept-2-ene-1-one (Hamp) in acetone. The characterization of the complex by elemental analysis, infrared and 1H NMR spectroscopy and X-ray crystallography shows that amp is coordinated as a monoanionic NNO-donor chelate as an amino-amido ketone. However, the reaction of the similar ligand 7- amino-4,7-dimethyl-5-aza-3-octen-2-one (Hada) with [Re(CO)5Br] produced the product fac-[Re(CO)3Br(Hada)], with Hada coordinated as a neutral NN-donor amino-imino-ketone.
- Full Text:
- Date Issued: 2009
Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus)
- Authors: Andrews, Allen Hia
- Date: 2009
- Subjects: Fishes -- Age determination , Fishes -- Southern hemisphere -- Longevity , Fishes -- Growth , Radioactive dating , Patagonian toothfish , Patagonian toothfish -- Fisheries , Orange roughy , Orange roughy -- Fisheries , Deep-sea fishes -- Southern hemisphere , Deep-sea fisheries , Deep-sea fisheries -- Southern hemisphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5295 , http://hdl.handle.net/10962/d1005140
- Description: Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies since the first lead-radium dating study on fish in 1982. The activity of radium-226 measurements ranged over 3 orders of magnitude (<0.001 to >1.0 dpm.g⁻¹). An analysis revealed ontogenetic differences in radium-226 uptake that may be attributed to changes in habitat or diet. Radiometric age from otolith core studies was used to describe a radium-226 uptake time-series for some species, which revealed interesting patterns over long periods. This synopsis provides information on the uptake of radium-226 to otoliths from an environmental perspective, which can be used as a basis for future studies.
- Full Text:
- Date Issued: 2009
- Authors: Andrews, Allen Hia
- Date: 2009
- Subjects: Fishes -- Age determination , Fishes -- Southern hemisphere -- Longevity , Fishes -- Growth , Radioactive dating , Patagonian toothfish , Patagonian toothfish -- Fisheries , Orange roughy , Orange roughy -- Fisheries , Deep-sea fishes -- Southern hemisphere , Deep-sea fisheries , Deep-sea fisheries -- Southern hemisphere
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5295 , http://hdl.handle.net/10962/d1005140
- Description: Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies since the first lead-radium dating study on fish in 1982. The activity of radium-226 measurements ranged over 3 orders of magnitude (<0.001 to >1.0 dpm.g⁻¹). An analysis revealed ontogenetic differences in radium-226 uptake that may be attributed to changes in habitat or diet. Radiometric age from otolith core studies was used to describe a radium-226 uptake time-series for some species, which revealed interesting patterns over long periods. This synopsis provides information on the uptake of radium-226 to otoliths from an environmental perspective, which can be used as a basis for future studies.
- Full Text:
- Date Issued: 2009
Student's van Hiele levels of geometric thought and conception in plane geometry: a collective case study of Nigeria and South Africa
- Authors: Atebe, Humphrey Uyouyo
- Date: 2009
- Subjects: Geometry -- Study and teaching (Secondary) -- Nigeria -- Case studies Geometry -- Study and teaching (Secondary) -- South Africa -- Case studies Mathematics -- Study and teaching (Secondary) -- Nigeria -- Case studies Mathematics -- Study and teaching (Secondary) -- South Africa -- Case studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1777 , http://hdl.handle.net/10962/d1003662
- Description: This study is inspired by and utilises the van Hiele theory of geometric thought levels, currently acclaimed as one of the best frameworks for studying teaching and learning processes in geometry. The study aims both to explore and explicate the van Hiele levels of geometric thinking of a selected group of grade 10, 11 and 12 learners in Nigerian and South African schools. The study further aims to provide a rich and indepth description of the geometry instructional practices that possibly contributed to the levels of geometric conceptualisation exhibited by this cohort of high school learners. This collective case study, presented in two volumes, is oriented within an interpretive research paradigm and characterised by both qualitative and quantitative methods. The sample for the study comprised a total of 144 mathematics learners and 6 mathematics teachers from Nigeria and South Africa. They were selected using both purposive and stratified sampling techniques. In using the van Hiele model to interrogate both learners’ levels of geometric conceptualisation and teaching methods in geometry classrooms, the study employs a qualitative and qunatitative approach to the data-collection process, involving the use of questionnaires (in the form of various pen-and-paper tests, hands-on activity-based tests), interviews and classroom videos. Although the data analysis was done largely through descriptive statistics, the whole process inevitably incorporated elements of inferential statistics (e.g. ANOVA and Tukey HSD post-hoc test) in the quest for indepth analysis and deeper interpretation of the data. Learners were assigned to various van Hiele levels, mainly according to Usiskin’s (1982) forced van Hiele level determination scheme. The whole process of analysing the classroom videos involved a consultative panel of 4 observers and 3 critical readers, using the checklist of van Hiele phase descriptors to guide the analysis process. Concerning learners’ levels of geometric conceptualisation, the results from this study reveal that the most of the learners were not yet ready for the formal deductive study of school geometry, as only 2% and 3% of them were respectively at van Hiele levels 3 and 4, while 47%, 22% and 24% were at levels 0, 1 and 2, respectively. More learners from the Nigerian subsample (53%) were at van Hiele level 0 than learners from the South African subsample (41%) at this level. No learner from the Nigerian subsample was at van Hiele level 4, while 6% of the South African learners were at level 4. In general, learners from the Nigerian subsample had a poorer knowledge of school geometry than their peers from the South African subsample, as learners from the latter subsample obtained significantly higher mean scores in the van Hiele Geometry Test (VHGT) and each of the other tests used in this study. Results relating to gender differences in performance generally favour the male learners in this study. For each of the participating schools, learners’ van Hiele levels (as determined by their scores on the VHGT) strongly correlate with their performance in geometry content tests and mathematics generally. For each of the Nigerian and South African subsamples, for n ≤ 2, learners at van Hiele level n obtained higher means on nearly all the tests administered in this study than their peers at level n–1. This finding provides support for the hierarchical property of the van Hiele levels.
- Full Text:
- Date Issued: 2009
- Authors: Atebe, Humphrey Uyouyo
- Date: 2009
- Subjects: Geometry -- Study and teaching (Secondary) -- Nigeria -- Case studies Geometry -- Study and teaching (Secondary) -- South Africa -- Case studies Mathematics -- Study and teaching (Secondary) -- Nigeria -- Case studies Mathematics -- Study and teaching (Secondary) -- South Africa -- Case studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1777 , http://hdl.handle.net/10962/d1003662
- Description: This study is inspired by and utilises the van Hiele theory of geometric thought levels, currently acclaimed as one of the best frameworks for studying teaching and learning processes in geometry. The study aims both to explore and explicate the van Hiele levels of geometric thinking of a selected group of grade 10, 11 and 12 learners in Nigerian and South African schools. The study further aims to provide a rich and indepth description of the geometry instructional practices that possibly contributed to the levels of geometric conceptualisation exhibited by this cohort of high school learners. This collective case study, presented in two volumes, is oriented within an interpretive research paradigm and characterised by both qualitative and quantitative methods. The sample for the study comprised a total of 144 mathematics learners and 6 mathematics teachers from Nigeria and South Africa. They were selected using both purposive and stratified sampling techniques. In using the van Hiele model to interrogate both learners’ levels of geometric conceptualisation and teaching methods in geometry classrooms, the study employs a qualitative and qunatitative approach to the data-collection process, involving the use of questionnaires (in the form of various pen-and-paper tests, hands-on activity-based tests), interviews and classroom videos. Although the data analysis was done largely through descriptive statistics, the whole process inevitably incorporated elements of inferential statistics (e.g. ANOVA and Tukey HSD post-hoc test) in the quest for indepth analysis and deeper interpretation of the data. Learners were assigned to various van Hiele levels, mainly according to Usiskin’s (1982) forced van Hiele level determination scheme. The whole process of analysing the classroom videos involved a consultative panel of 4 observers and 3 critical readers, using the checklist of van Hiele phase descriptors to guide the analysis process. Concerning learners’ levels of geometric conceptualisation, the results from this study reveal that the most of the learners were not yet ready for the formal deductive study of school geometry, as only 2% and 3% of them were respectively at van Hiele levels 3 and 4, while 47%, 22% and 24% were at levels 0, 1 and 2, respectively. More learners from the Nigerian subsample (53%) were at van Hiele level 0 than learners from the South African subsample (41%) at this level. No learner from the Nigerian subsample was at van Hiele level 4, while 6% of the South African learners were at level 4. In general, learners from the Nigerian subsample had a poorer knowledge of school geometry than their peers from the South African subsample, as learners from the latter subsample obtained significantly higher mean scores in the van Hiele Geometry Test (VHGT) and each of the other tests used in this study. Results relating to gender differences in performance generally favour the male learners in this study. For each of the participating schools, learners’ van Hiele levels (as determined by their scores on the VHGT) strongly correlate with their performance in geometry content tests and mathematics generally. For each of the Nigerian and South African subsamples, for n ≤ 2, learners at van Hiele level n obtained higher means on nearly all the tests administered in this study than their peers at level n–1. This finding provides support for the hierarchical property of the van Hiele levels.
- Full Text:
- Date Issued: 2009
Access to credit and the effect of credit constraints on household welfare in the Eastern Cape province, South Africa
- Baiyegunhi, Lloyd-James Segun
- Authors: Baiyegunhi, Lloyd-James Segun
- Date: 2009
- Subjects: Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11153 , http://hdl.handle.net/10353/d1000977 , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Description: In recent years, concern about food safety linked to health issues has seen a rise in private food safety standards in addition to the regulations set by the Food and Agriculture Organisation (FAO) in collaboration with the World Health Organisation (WHO). These have presented challenges to producers and exporters of agricultural food products especially the producers of fresh fruits and vegetables. In spite of the food safety-linked challenges from the demand side, the vast range of business-environment forces pose equally formidable challenges that negatively impact on the exporting industries’ ability to maintain or improve their market shares and their ability to compete in world markets. The objective of this study was therefore to establish the competitiveness of the South African citrus industry in the international markets within this prevailing scenario. Due to the diversity of the definitions of competitiveness as a concept, this study formulated the following working definition: “the ability to create, deliver and maintain value and constant market share through strategic management of the industrial environment or competitiveness drivers”. This was based on the understanding that the international market shares of an industry are a function of forces in the business environment which range from intra-industry, external and national as well as the international elements. The unit of analysis were the citrus producers engaged in export of their products and the study made use of 151 responses by producers. The study adopted a five-step approach to the analysis of the performance of the South African citrus industry in the global markets, starting with the analysis of the Constant Market Share (CMS) of the South African citrus industry in various world markets, establishing the impact of the business environmental factors upon competitiveness, establishing the costs of compliance with private food safety standards, determining the non-price benefits of compliance with the standards, as well as highlighting the strategies for enhancing long-term competitiveness of the industry in the international markets. South Africa is one of the top three countries dominating the citrus fruit export market. Since its entry into the citrus fruit exports market in the 1900s, the industry has sustained its activity in the international market. The Constant Market Share Analysis shows that, amidst the challenges on the international market side, and the changes in the business environment, over much of which the industry has limited control and influence, the industry has maintained its competitive advantage in several markets. The CMS shows that South Africa’s lemons are competitive in America. Despite a negative trend, the South African grapefruit has been competitive in France, Greece, Italy, the Netherlands and Spain. Oranges have been competitive in the Greece, Italy, Portugal, UK, Asian and Northern Europe markets. Competitiveness in these markets has been due to the inherent competitiveness of the industry. Competitiveness in such markets as the Middle East has been attributed to the relatively rapid growth of these markets. The South African citrus industry has similarly undergone many major processes of transformation. The business environmental factors influencing its performance have ranged reform to the challenges beyond the country’s borders. These factors directly and indirectly affect the performance of the industry in the export market. They have influenced the flow of fruits into different international destinations. Of major concern are the food safety and private standards. Challenges in traditional markets as well as opportunities presented by demand from newly emerging citrus consuming nations have seen a diversification in the marketing of the South African citrus. The intensity of competition in the global market is reflected by the fluctuations in the market shares in different markets as well as the increase and fluctuations of fruit rejection rates in some lucrative markets such as America. A combination of challenging national environmental forces and stringent demand conditions negatively impact on revenues especially from markets characterised by price competitiveness. This study identified cost of production, foreign market support systems, adaptability, worker skills, challenges of management in an international environment and government policies such as labour and trade policies as some of the most influential obstacles to competitiveness. Some of the most competiveness-enhancing factors were market availability, market size, market information, market growth and the availability of research institutions. However, compliance with private standards still poses a challenge to the exporters. The different performance levels of the industry in various markets prove the dissimilarity of the demand conditions in the global market. These are supported by the negative influence associated with the foreign market support regimes as well as the challenges associated with compliance with private food safety standards. While market availability, market growth, market information and size were identified as enhancing competitiveness, the fluctuations and inconsistencies in the competitiveness of the industry in different foreign markets require more than finding markets. Resource allocation by both the government and the industry may need to take into account the off-setting of the national challenges and support of farmers faced with distorted and unfair international playing fields. Otherwise, market availability is not a challenge for the industry save meeting the specifications therewith as well as price competitiveness which is unattainable for the South African citrus producers faced with high production costs. For the purposes of further study, it is recommended that account should be taken of all the products marketed by the industry (including processed products such as fruit juices) in order to have a whole picture of the competitiveness of the industry in the international market. This study also proffers a new theoretical framework for the analysis of the business environment for the citrus industry and other agro-businesses. This framework takes into account the indispensability of the food safety standards and measures as well as the diversity of the global consumer and the non-negotiability of food trade for the sustenance of the growing population.
- Full Text:
- Date Issued: 2009
- Authors: Baiyegunhi, Lloyd-James Segun
- Date: 2009
- Subjects: Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Agricultural Economics)
- Identifier: vital:11153 , http://hdl.handle.net/10353/d1000977 , Rural poor -- South Africa -- Eastern Cape , Households -- Economic aspects -- South Africa -- Eastern Cape , Investments -- South Africa -- Eastern Cape , Finance -- South Africa -- Eastern Cape , Credit -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Description: In recent years, concern about food safety linked to health issues has seen a rise in private food safety standards in addition to the regulations set by the Food and Agriculture Organisation (FAO) in collaboration with the World Health Organisation (WHO). These have presented challenges to producers and exporters of agricultural food products especially the producers of fresh fruits and vegetables. In spite of the food safety-linked challenges from the demand side, the vast range of business-environment forces pose equally formidable challenges that negatively impact on the exporting industries’ ability to maintain or improve their market shares and their ability to compete in world markets. The objective of this study was therefore to establish the competitiveness of the South African citrus industry in the international markets within this prevailing scenario. Due to the diversity of the definitions of competitiveness as a concept, this study formulated the following working definition: “the ability to create, deliver and maintain value and constant market share through strategic management of the industrial environment or competitiveness drivers”. This was based on the understanding that the international market shares of an industry are a function of forces in the business environment which range from intra-industry, external and national as well as the international elements. The unit of analysis were the citrus producers engaged in export of their products and the study made use of 151 responses by producers. The study adopted a five-step approach to the analysis of the performance of the South African citrus industry in the global markets, starting with the analysis of the Constant Market Share (CMS) of the South African citrus industry in various world markets, establishing the impact of the business environmental factors upon competitiveness, establishing the costs of compliance with private food safety standards, determining the non-price benefits of compliance with the standards, as well as highlighting the strategies for enhancing long-term competitiveness of the industry in the international markets. South Africa is one of the top three countries dominating the citrus fruit export market. Since its entry into the citrus fruit exports market in the 1900s, the industry has sustained its activity in the international market. The Constant Market Share Analysis shows that, amidst the challenges on the international market side, and the changes in the business environment, over much of which the industry has limited control and influence, the industry has maintained its competitive advantage in several markets. The CMS shows that South Africa’s lemons are competitive in America. Despite a negative trend, the South African grapefruit has been competitive in France, Greece, Italy, the Netherlands and Spain. Oranges have been competitive in the Greece, Italy, Portugal, UK, Asian and Northern Europe markets. Competitiveness in these markets has been due to the inherent competitiveness of the industry. Competitiveness in such markets as the Middle East has been attributed to the relatively rapid growth of these markets. The South African citrus industry has similarly undergone many major processes of transformation. The business environmental factors influencing its performance have ranged reform to the challenges beyond the country’s borders. These factors directly and indirectly affect the performance of the industry in the export market. They have influenced the flow of fruits into different international destinations. Of major concern are the food safety and private standards. Challenges in traditional markets as well as opportunities presented by demand from newly emerging citrus consuming nations have seen a diversification in the marketing of the South African citrus. The intensity of competition in the global market is reflected by the fluctuations in the market shares in different markets as well as the increase and fluctuations of fruit rejection rates in some lucrative markets such as America. A combination of challenging national environmental forces and stringent demand conditions negatively impact on revenues especially from markets characterised by price competitiveness. This study identified cost of production, foreign market support systems, adaptability, worker skills, challenges of management in an international environment and government policies such as labour and trade policies as some of the most influential obstacles to competitiveness. Some of the most competiveness-enhancing factors were market availability, market size, market information, market growth and the availability of research institutions. However, compliance with private standards still poses a challenge to the exporters. The different performance levels of the industry in various markets prove the dissimilarity of the demand conditions in the global market. These are supported by the negative influence associated with the foreign market support regimes as well as the challenges associated with compliance with private food safety standards. While market availability, market growth, market information and size were identified as enhancing competitiveness, the fluctuations and inconsistencies in the competitiveness of the industry in different foreign markets require more than finding markets. Resource allocation by both the government and the industry may need to take into account the off-setting of the national challenges and support of farmers faced with distorted and unfair international playing fields. Otherwise, market availability is not a challenge for the industry save meeting the specifications therewith as well as price competitiveness which is unattainable for the South African citrus producers faced with high production costs. For the purposes of further study, it is recommended that account should be taken of all the products marketed by the industry (including processed products such as fruit juices) in order to have a whole picture of the competitiveness of the industry in the international market. This study also proffers a new theoretical framework for the analysis of the business environment for the citrus industry and other agro-businesses. This framework takes into account the indispensability of the food safety standards and measures as well as the diversity of the global consumer and the non-negotiability of food trade for the sustenance of the growing population.
- Full Text:
- Date Issued: 2009
A public-private partnership model for the improvemnet of local economic development in South African metropolitan government
- Binza, Mzikayise Shakespeare
- Authors: Binza, Mzikayise Shakespeare
- Date: 2009
- Subjects: Economic development -- South Africa , Public-private sector cooperation -- South Africa , South Africa -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8159 , http://hdl.handle.net/10948/923 , Economic development -- South Africa , Public-private sector cooperation -- South Africa , South Africa -- Economic conditions
- Description: The post-apartheid developmental state of South Africa had a challenge of turning around an economy that was on deficit which it inherited in 1994, to a positive growth that will be sustainable and shared. The process followed in creating a sustainable economic development was first establishing a constitutional democratic government which was constituted in terms of the provisions of the Constitution of the Republic of South Africa, 1996, as three equal spheres of government, viz: the national, provincial and local spheres of government. Initiatives on innovative economic development become a reconstruction programme not only of the national and provincial spheres of government, but also of the local sphere of government which is closest to the people it governs and deliver municipal goods and services to. For an example, section 152 (1) (c) of the Constitution of the Republic of South Africa, 1996, provides that the local sphere of government which is constituted by 283 wall-to-wall municipalities must “improve social and economic development” of the people. Out of the 283 municipalities, 6 are metropolitan municipalities, and are the: City of Cape Town, City of Johannesburg, City of Tshwane, Ekurhuleni, Ethekwini, and Nelson Mandela Bay Municipality. This research project is limited to the City of Cape Town (CCT) and the Nelson Mandela Bay Municipalities (NMBM). In the second process, a number of legislations and policies providing for external mechanisms to be used to improve local economic development (LED) in an inclusive, shared and equitable manner were introduced. Policies that were introduced by the democratic government and serve as policy directive for economic development are: the Reconstruction and Development Programme (RDP) of 1994; the Growth, Employment and Redistribution (GEAR) of 1996; and the Accelerated and Shared Growth Initiative of South Africa (ASGISA) of 2006. The relevant legislations to the local sphere of government which were introduced and provided for the appropriate mechanism for enabling sustainable growth of local economies by developmental local government in partnerships with other stakeholders such as private sector and civil society movements are: the Local Government: Municipal Systems Act, 2000 (Act 32 of 2000); Municipal Service Policy of 2000; Guidelines on Municipal Service Partnerships of 2006-2010; and the National Framework for Local Economic Development in South Africa (NFLED) of 2006-2010. The above xviii legislations provide the following external mechanisms to improve local economic development in municipal areas, viz: public-private partnerships; public-public partnerships, and public-community partnerships. This research project is about the first external mechanism which is the public-private partnerships (PPPs) to enable municipalities to improve local economies that provide for job creations and employment for the local inhabitants. According to the National Treasury Regulation 16 (2004:1), PPP means a “commercial transaction between an institution, for example a metropolitan government, and a private party in terms of which: 1. The private party either performs an institutional function on behalf of the institution [in this regard a metropolitan government] for a specified or indefinite period or acquires the use of a state property for its own commercial purposes for a specified or indefinite period. 2. The private party receives a benefit for performing the function or by utilising state property, either by way of compensation from a revenue fund, or by charges or fees collected by the private party from users or customers of a service provided for them; or a combination of such compensation and such fees”. The first goal of this research project is to develop the most appropriate public-private partnership model for South African metropolitan government with special reference to the City of Cape Town (CCT) and the Nelson Mandela Bay Municipality (NMBM) in enabling and guiding them to improve and sustain local economic development (LED) in their respective areas of jurisdiction. The application of public-private partnerships (PPPs) as a policy strategy to achieve local economic development (LED) in CCT and NMBM was investigated, in order to determine whether these activities can be improved. Followed is the development of a conceptual framework for optimal PPP implementation in order to improve local economic development in the CCT and NMBM and other metropolitan and municipal areas in South Africa. A more appropriate PPP model called the Participatory Development Systems Model (PDSM) has been constructed for this purpose from a number of sources and proven good practices both locally in South Africa and internationally. The PDSM model uses the strategic prioritisation and management by a municipality of the integrated development of physical, economic, human and social capital in its region in a more participatory way, as a point of departure for PPPs. The PDSM model for PPPs also emphasises consistent systematic assessment of these strategies against the strategic LED goals of the municipality concerned in order to ensure that lessons are learnt from these experiences and used to refine or revise future LED and PPP strategies accordingly. This thesis makes an original contribution to the existing body of knowledge about the promotion of LED through PPPs in metropolitan municipalities in South Africa and elsewhere, by conceptualising PPPs in a clear and coherent way as an integrated dimension of strategic management processes in municipalities that need to be implemented in a more participatory way in order to achieve the overall strategic goal of sustainable LED.
- Full Text:
- Date Issued: 2009
- Authors: Binza, Mzikayise Shakespeare
- Date: 2009
- Subjects: Economic development -- South Africa , Public-private sector cooperation -- South Africa , South Africa -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8159 , http://hdl.handle.net/10948/923 , Economic development -- South Africa , Public-private sector cooperation -- South Africa , South Africa -- Economic conditions
- Description: The post-apartheid developmental state of South Africa had a challenge of turning around an economy that was on deficit which it inherited in 1994, to a positive growth that will be sustainable and shared. The process followed in creating a sustainable economic development was first establishing a constitutional democratic government which was constituted in terms of the provisions of the Constitution of the Republic of South Africa, 1996, as three equal spheres of government, viz: the national, provincial and local spheres of government. Initiatives on innovative economic development become a reconstruction programme not only of the national and provincial spheres of government, but also of the local sphere of government which is closest to the people it governs and deliver municipal goods and services to. For an example, section 152 (1) (c) of the Constitution of the Republic of South Africa, 1996, provides that the local sphere of government which is constituted by 283 wall-to-wall municipalities must “improve social and economic development” of the people. Out of the 283 municipalities, 6 are metropolitan municipalities, and are the: City of Cape Town, City of Johannesburg, City of Tshwane, Ekurhuleni, Ethekwini, and Nelson Mandela Bay Municipality. This research project is limited to the City of Cape Town (CCT) and the Nelson Mandela Bay Municipalities (NMBM). In the second process, a number of legislations and policies providing for external mechanisms to be used to improve local economic development (LED) in an inclusive, shared and equitable manner were introduced. Policies that were introduced by the democratic government and serve as policy directive for economic development are: the Reconstruction and Development Programme (RDP) of 1994; the Growth, Employment and Redistribution (GEAR) of 1996; and the Accelerated and Shared Growth Initiative of South Africa (ASGISA) of 2006. The relevant legislations to the local sphere of government which were introduced and provided for the appropriate mechanism for enabling sustainable growth of local economies by developmental local government in partnerships with other stakeholders such as private sector and civil society movements are: the Local Government: Municipal Systems Act, 2000 (Act 32 of 2000); Municipal Service Policy of 2000; Guidelines on Municipal Service Partnerships of 2006-2010; and the National Framework for Local Economic Development in South Africa (NFLED) of 2006-2010. The above xviii legislations provide the following external mechanisms to improve local economic development in municipal areas, viz: public-private partnerships; public-public partnerships, and public-community partnerships. This research project is about the first external mechanism which is the public-private partnerships (PPPs) to enable municipalities to improve local economies that provide for job creations and employment for the local inhabitants. According to the National Treasury Regulation 16 (2004:1), PPP means a “commercial transaction between an institution, for example a metropolitan government, and a private party in terms of which: 1. The private party either performs an institutional function on behalf of the institution [in this regard a metropolitan government] for a specified or indefinite period or acquires the use of a state property for its own commercial purposes for a specified or indefinite period. 2. The private party receives a benefit for performing the function or by utilising state property, either by way of compensation from a revenue fund, or by charges or fees collected by the private party from users or customers of a service provided for them; or a combination of such compensation and such fees”. The first goal of this research project is to develop the most appropriate public-private partnership model for South African metropolitan government with special reference to the City of Cape Town (CCT) and the Nelson Mandela Bay Municipality (NMBM) in enabling and guiding them to improve and sustain local economic development (LED) in their respective areas of jurisdiction. The application of public-private partnerships (PPPs) as a policy strategy to achieve local economic development (LED) in CCT and NMBM was investigated, in order to determine whether these activities can be improved. Followed is the development of a conceptual framework for optimal PPP implementation in order to improve local economic development in the CCT and NMBM and other metropolitan and municipal areas in South Africa. A more appropriate PPP model called the Participatory Development Systems Model (PDSM) has been constructed for this purpose from a number of sources and proven good practices both locally in South Africa and internationally. The PDSM model uses the strategic prioritisation and management by a municipality of the integrated development of physical, economic, human and social capital in its region in a more participatory way, as a point of departure for PPPs. The PDSM model for PPPs also emphasises consistent systematic assessment of these strategies against the strategic LED goals of the municipality concerned in order to ensure that lessons are learnt from these experiences and used to refine or revise future LED and PPP strategies accordingly. This thesis makes an original contribution to the existing body of knowledge about the promotion of LED through PPPs in metropolitan municipalities in South Africa and elsewhere, by conceptualising PPPs in a clear and coherent way as an integrated dimension of strategic management processes in municipalities that need to be implemented in a more participatory way in order to achieve the overall strategic goal of sustainable LED.
- Full Text:
- Date Issued: 2009
Rhenium (I) and (V) complexes with potentially mulidentate ligands containing the Amino group
- Authors: Booysen, Irvin Noel
- Date: 2009
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10386 , http://hdl.handle.net/10948/1270 , Rhenium , Ligands
- Description: The complex trans-[Re(dab)Cl3(PPh3)2] (H2dab = 1,2-diaminobenzene) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2dab in ethanol. The ligand dab is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only in a distorted octahedral coordination geometry around the metal ion. The complex trans- [Re(ada)Cl3(PPh3)2] (H2ada = 2-aminodiphenylamine) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2ada in acetonitrile. The ligand ada is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only, in a distorted octahedral coordination geometry around the metal ion. The ‘2 + 1’ complex fac- [Re(CO)3(Hamp)(amp)] (Hamp = 2-aminophenol) was isolated from the reaction of a two molar ratio of Hamp with [Re(CO)5Br] in toluene. The reaction of a 1:1 molar ratio of [Re(CO)5Br] and H2ada led to the isolation of the Re(I) complex, fac- [Re(CO)3Br(H2ada)]. The reaction of equimolar quantities of cis-[ReO2I(PPh3)2] with 5,6-diamino-1,3- dimethyluracil (H2ddd) in acetonitrile led to the formation of [Re(ddd)(Hddd)I(PPh3)2](ReO4). The X-ray crystal structure shows that the ligand ddd is coordinated monodentately through the doubly deprotonated amino nitrogen and is therefore present as an imide. The chelate Hddd is coordinated bidentately via the neutral amino nitrogen, which is coordinated trans to the imido nitrogen, and the singly deprotonated amido nitrogen, trans to the iodide. The reaction of trans-[ReOCl3(PPh3)2] with N-(2-aminobenzylidene)-5-amino-1,3-dimethyl uracil (H3dua) in ethanol gave a mixed crystal which contains both the neutral oxorhenium(V) complex [ReOCl(Hdua)] and the imido rhenium(V) [Re(dua)Cl2(PPh3)] in an equimolar ratio in the asymmetric unit. The reaction of equimolar quantities of [NH4(ReO4)] with H2ddd in methanol under reflux led to the isolation of [C12H12N6O4] as only product. The [ReO4]- anion is therefore instrumental in the formation of [C12H12N6O4], and since the product contains no rhenium in any oxidation state, the conclusion is that [ReO4]- catalyses the oxidative deamination Abstract I.N. Booysen Nelson Mandela Metropolitan University vii of H2ddd. The X-ray crystal structure consists of two centrosymmetric, tricyclic rings, comprising a central pyrazine ring and two terminal pyrimidine rings. The reaction of 2-(2-aminophenyl)benzothiazole (Habt) with [Re(CO)5Br] led to the isolation of the rhenium(I) complex fac-[Re(Habt)(CO)3Br]. With trans-[ReOCl3(PPh3)2], the ligand Habt decomposed to form the oxofree rhenium(V) complex [Re(itp)2Cl(PPh3)] (itp = 2-amidophenylthiolate). From the reaction of trans-[ReOBr3(PPh3)2] with 2-(2- hydroxyphenyl)benzothiazole (Hhpd) the complex [ReVOBr2(hpd)(PPh3)] was obtained. The reaction of a twofold molar excess of H2apb (2-(2-aminophenyl)-1-benzimidazole) with trans-[ReO2(py)4]Cl in ethanol gave the green product of formulation [ReO(Hapb)(apb)] in good yield. The rhenium atom lies in a distorted trigonalbipyramidal environment. The two imidazole N(2) atoms lie in the apical positions trans to each other, with the oxo-oxygen and two amido N(1) atoms in the trigonal plane. A new nitrosylrhenium(II) complex salt, [Re(NO)BrL2(PPh3)2](ReO4) (H2L2 = 2-amino-5- (triphenylphosphino)phenol), is the first example of a complex containing the triphenylphosphonium-amidophenolate ligand L2, formed by the nucleophilic attack of a PPh3 on a coordinated amidophenolate ring. The complex salt trans-[Re(mps)Cl(PPh3)2](ReO4) (H3mps = N-(2-amino-3- methylphenyl)salicylideneimine) was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps. The X-ray crystal structure shows that the trianionic ligand mps acts as a tridentate chelate via the doubly deprotonated amino nitrogen (an imide), the neutral imino nitrogen and the deprotonated phenolic oxygen. The six-coordinated complex cis-[Re(mps)Cl2(PPh3)2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps in benzene. The X-ray crystal structure show that the mps ligand coordinates as a tridentate chelate via the doubly deprotonated 2-amino nitrogen, the neutral imino nitrogen and the phenolate oxygen. The imide and phenolate oxygen coordinate trans to each other in a distorted octahedral geometry, around the rhenium(V) centre, with the two chlorides in cis positions. A new oxofree rhenium(V) complex salt, [Re(bbd)2](ReO4) ( H2bbd = N-(2- Abstract I.N. Booysen Nelson Mandela Metropolitan University viii aminobenzylidene)benzene-1,2-diamine), has been synthesized and the chelates bbd are coordinated as dianionic tridentate N,N,N-donor diamidoimines. The rhenium(V) ion is centered in a distorted trigonal prism. The rhenium(I) compound fac-[Re(CO)3(daa)].Hpab.H2O (Hpab = N1,N2-(1,2- phenylene)bis(2-aminobenzamide); Hdaa = 2-amino-N-(2-aminophenyl)benzamide) was synthesized from the reaction of [Re(CO)5Br] with a two equivalents of Hpab in toluene. The monoanionic tridentate ligand daa was formed by the rhenium-mediated cleavage of an amido N-C bond of the potentially tetradentate ligand Hpab. Daa is coordinated as a diaminoamide via three nitrogen-donor atoms. The reaction of a twofold molar excess of H2amben (H2amben = N1,N2-bis(2-aminobenzylidene)ethane-1,2-diamine) with trans- [ReOBr3(PPh3)2] gave the oxorhenium(V) cationic complex [ReO(amben)]X (X = Br-, PF6 -). The Re(V) oxo-bridged compound, {μ-O}[ReO(omben)]2.H2O (H2omben = N1,N2- bis(2-hydroxybenzylidene)ethane-1,2-diamine) was isolated from the reaction of a 2:1 molar ratio of H2omben and trans-[ReO2(py)4]Cl in methanol. The seven-coordinate rhenium(III) complex cation [ReIII(dhp)(PPh3)2]+ was isolated as the [ReO4]- salt from the reaction of cis-[ReVO2I(PPh3)2] with 2,6-bis(2- hydroxyphenyliminomethyl)pyridine (H2dhp) in ethanol. In the complex fac- [Re(CO)3(H2dhp)Br], prepared from [Re(CO)5Br] and H2dhp in toluene, the H2dhp ligand acts as a neutral bidentate N,N-donor chelate. An equimolar ratio reaction of 2-aminobenzaldehyde and 2-(2-aminophenyl)-1- benzimidazole in methanol led to 2-(5,6-dihydrobenzimidazolo[1,2-c]-quinazolin-6- yl)aniline. In an attempt to explore the template formation of this class of ligand with rhenium, the reaction of salicylaldehyde and 2-(2-aminophenyl)-1-benzimidazole in ethanol which was followed by the addition of trans-[ReOBr3(PPh3)2] led to the formation of the salt, 6-(2-hydroxyphenyl)-5,6-dihydrobenzimidazolo[1,2-c]quinazolin- 12-ium bromide. The compound 6-(2-methylthiophenyl)-5,6-dihydrobenzimidazolo[1,2- c]quinazolin-12-ium was synthesized via the reaction of 2-aminobenzaldehyde and 2- methylthiobenzaldehyde in methanol.
- Full Text:
- Date Issued: 2009
- Authors: Booysen, Irvin Noel
- Date: 2009
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10386 , http://hdl.handle.net/10948/1270 , Rhenium , Ligands
- Description: The complex trans-[Re(dab)Cl3(PPh3)2] (H2dab = 1,2-diaminobenzene) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2dab in ethanol. The ligand dab is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only in a distorted octahedral coordination geometry around the metal ion. The complex trans- [Re(ada)Cl3(PPh3)2] (H2ada = 2-aminodiphenylamine) was prepared from the reaction of trans-[ReOCl3(PPh3)2] with H2ada in acetonitrile. The ligand ada is coordinated to the rhenium(V) centre through a dianionic imido nitrogen only, in a distorted octahedral coordination geometry around the metal ion. The ‘2 + 1’ complex fac- [Re(CO)3(Hamp)(amp)] (Hamp = 2-aminophenol) was isolated from the reaction of a two molar ratio of Hamp with [Re(CO)5Br] in toluene. The reaction of a 1:1 molar ratio of [Re(CO)5Br] and H2ada led to the isolation of the Re(I) complex, fac- [Re(CO)3Br(H2ada)]. The reaction of equimolar quantities of cis-[ReO2I(PPh3)2] with 5,6-diamino-1,3- dimethyluracil (H2ddd) in acetonitrile led to the formation of [Re(ddd)(Hddd)I(PPh3)2](ReO4). The X-ray crystal structure shows that the ligand ddd is coordinated monodentately through the doubly deprotonated amino nitrogen and is therefore present as an imide. The chelate Hddd is coordinated bidentately via the neutral amino nitrogen, which is coordinated trans to the imido nitrogen, and the singly deprotonated amido nitrogen, trans to the iodide. The reaction of trans-[ReOCl3(PPh3)2] with N-(2-aminobenzylidene)-5-amino-1,3-dimethyl uracil (H3dua) in ethanol gave a mixed crystal which contains both the neutral oxorhenium(V) complex [ReOCl(Hdua)] and the imido rhenium(V) [Re(dua)Cl2(PPh3)] in an equimolar ratio in the asymmetric unit. The reaction of equimolar quantities of [NH4(ReO4)] with H2ddd in methanol under reflux led to the isolation of [C12H12N6O4] as only product. The [ReO4]- anion is therefore instrumental in the formation of [C12H12N6O4], and since the product contains no rhenium in any oxidation state, the conclusion is that [ReO4]- catalyses the oxidative deamination Abstract I.N. Booysen Nelson Mandela Metropolitan University vii of H2ddd. The X-ray crystal structure consists of two centrosymmetric, tricyclic rings, comprising a central pyrazine ring and two terminal pyrimidine rings. The reaction of 2-(2-aminophenyl)benzothiazole (Habt) with [Re(CO)5Br] led to the isolation of the rhenium(I) complex fac-[Re(Habt)(CO)3Br]. With trans-[ReOCl3(PPh3)2], the ligand Habt decomposed to form the oxofree rhenium(V) complex [Re(itp)2Cl(PPh3)] (itp = 2-amidophenylthiolate). From the reaction of trans-[ReOBr3(PPh3)2] with 2-(2- hydroxyphenyl)benzothiazole (Hhpd) the complex [ReVOBr2(hpd)(PPh3)] was obtained. The reaction of a twofold molar excess of H2apb (2-(2-aminophenyl)-1-benzimidazole) with trans-[ReO2(py)4]Cl in ethanol gave the green product of formulation [ReO(Hapb)(apb)] in good yield. The rhenium atom lies in a distorted trigonalbipyramidal environment. The two imidazole N(2) atoms lie in the apical positions trans to each other, with the oxo-oxygen and two amido N(1) atoms in the trigonal plane. A new nitrosylrhenium(II) complex salt, [Re(NO)BrL2(PPh3)2](ReO4) (H2L2 = 2-amino-5- (triphenylphosphino)phenol), is the first example of a complex containing the triphenylphosphonium-amidophenolate ligand L2, formed by the nucleophilic attack of a PPh3 on a coordinated amidophenolate ring. The complex salt trans-[Re(mps)Cl(PPh3)2](ReO4) (H3mps = N-(2-amino-3- methylphenyl)salicylideneimine) was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps. The X-ray crystal structure shows that the trianionic ligand mps acts as a tridentate chelate via the doubly deprotonated amino nitrogen (an imide), the neutral imino nitrogen and the deprotonated phenolic oxygen. The six-coordinated complex cis-[Re(mps)Cl2(PPh3)2] was prepared by the reaction of trans-[ReOCl3(PPh3)2] with a twofold molar excess of H3mps in benzene. The X-ray crystal structure show that the mps ligand coordinates as a tridentate chelate via the doubly deprotonated 2-amino nitrogen, the neutral imino nitrogen and the phenolate oxygen. The imide and phenolate oxygen coordinate trans to each other in a distorted octahedral geometry, around the rhenium(V) centre, with the two chlorides in cis positions. A new oxofree rhenium(V) complex salt, [Re(bbd)2](ReO4) ( H2bbd = N-(2- Abstract I.N. Booysen Nelson Mandela Metropolitan University viii aminobenzylidene)benzene-1,2-diamine), has been synthesized and the chelates bbd are coordinated as dianionic tridentate N,N,N-donor diamidoimines. The rhenium(V) ion is centered in a distorted trigonal prism. The rhenium(I) compound fac-[Re(CO)3(daa)].Hpab.H2O (Hpab = N1,N2-(1,2- phenylene)bis(2-aminobenzamide); Hdaa = 2-amino-N-(2-aminophenyl)benzamide) was synthesized from the reaction of [Re(CO)5Br] with a two equivalents of Hpab in toluene. The monoanionic tridentate ligand daa was formed by the rhenium-mediated cleavage of an amido N-C bond of the potentially tetradentate ligand Hpab. Daa is coordinated as a diaminoamide via three nitrogen-donor atoms. The reaction of a twofold molar excess of H2amben (H2amben = N1,N2-bis(2-aminobenzylidene)ethane-1,2-diamine) with trans- [ReOBr3(PPh3)2] gave the oxorhenium(V) cationic complex [ReO(amben)]X (X = Br-, PF6 -). The Re(V) oxo-bridged compound, {μ-O}[ReO(omben)]2.H2O (H2omben = N1,N2- bis(2-hydroxybenzylidene)ethane-1,2-diamine) was isolated from the reaction of a 2:1 molar ratio of H2omben and trans-[ReO2(py)4]Cl in methanol. The seven-coordinate rhenium(III) complex cation [ReIII(dhp)(PPh3)2]+ was isolated as the [ReO4]- salt from the reaction of cis-[ReVO2I(PPh3)2] with 2,6-bis(2- hydroxyphenyliminomethyl)pyridine (H2dhp) in ethanol. In the complex fac- [Re(CO)3(H2dhp)Br], prepared from [Re(CO)5Br] and H2dhp in toluene, the H2dhp ligand acts as a neutral bidentate N,N-donor chelate. An equimolar ratio reaction of 2-aminobenzaldehyde and 2-(2-aminophenyl)-1- benzimidazole in methanol led to 2-(5,6-dihydrobenzimidazolo[1,2-c]-quinazolin-6- yl)aniline. In an attempt to explore the template formation of this class of ligand with rhenium, the reaction of salicylaldehyde and 2-(2-aminophenyl)-1-benzimidazole in ethanol which was followed by the addition of trans-[ReOBr3(PPh3)2] led to the formation of the salt, 6-(2-hydroxyphenyl)-5,6-dihydrobenzimidazolo[1,2-c]quinazolin- 12-ium bromide. The compound 6-(2-methylthiophenyl)-5,6-dihydrobenzimidazolo[1,2- c]quinazolin-12-ium was synthesized via the reaction of 2-aminobenzaldehyde and 2- methylthiobenzaldehyde in methanol.
- Full Text:
- Date Issued: 2009
Characterisation of the plasmodium falciparum Hsp40 chaperones and their partnerships with Hsp70
- Authors: Botha, Melissa
- Date: 2009
- Subjects: Heat shock proteins Plasmodium falciparum Protein folding Molecular chaperones Malaria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3938 , http://hdl.handle.net/10962/d1003997
- Description: Central to this research, 40 kDa Heat shock proteins (Hsp40s) are known to partner (or cochaperone) 70 kDa Heat shock proteins (Hsp70s), facilitating the selection and transfer of protein substrate to Hsp70 and the stimulation of the protein folding ability of Hsp70. Members of the diverse Hsp70-Hsp40 protein complement of Plasmodium falciparum have been implicated in the cytoprotection of this malaria parasite, and are thought to facilitate the protein folding, assembly and translocation tasks required by the parasite to commandeer the infected human erythrocyte subsequent to invasion. In particular, the parasite has evolved an expanded and specialised 43- member suite of Hsp40 proteins, 19 of which bear an identifiable export motif for secretion into the infected erythrocyte cytoplasm where they potentially interact with human Hsp70. Although type I Hsp40 proteins are representative of typical regulators of Hsp70 activity, only two of these proteins are apparent in the parasite’s Hsp40 complement. These include a characteristic type I Hsp40 termed PfHsp40, and a larger, atypical type I Hsp40 termed Pfj1. Both Hsp40 proteins are predicted to be parasite-resident and are most likely to facilitate the co-chaperone regulation of the highly abundant and stress-inducible Hsp70 homolog, PfHsp70-I. In this work, the co-chaperone functionality of PfHsp40 and Pfj1 was elucidated using in vivo and in vitro assays. Purified recombinant PfHsp40 was shown to stimulate the ATPase activity of PfHsp70-I in in vitro single turnover and steady state ATPase assays, and co-operate with PfHsp70-I in in vitro aggregation suppression assays. In these in vitro assays, heterologous partnerships could be demonstrated between PfHsp70-I and the human Hsp40, Hsj1a, and human Hsp70 and PfHsp40, suggesting a common mode of Hsp70-Hsp40 interaction in the parasite and host organism. The functionality of the signature Hsp40 domain, the Jdomain, of Pfj1 was demonstrated by its ability to replace the equivalent domain of the A. tumefaciens Hsp40, Agt DnaJ, in interactions with the prokaryotic Hsp70, DnaK, in the thermosensitive dnaJ cbpA E. coli OD259 deletion strain. An H33Q mutation introduced into the invariant and crucial HPD tripeptide motif abrogated the functionality of the J-domain in the in vivo complementation system. These findings provide the first evidence for the conservation of the prototypical mode of J-domain based interaction of Hsp40 with Hsp70 in P. falciparum. Immunofluorescence staining revealed the localisation of PfHsp40 to the parasite cytoplasm, and Pfj1 to the parasite cytoplasm and nucleus in cultured intraerythrocytic stage P. falciparum parasites. PfHsp70-I was also shown to localise to the parasite cytoplasm and nucleus in these stages, consistent with the literature. Overall we propose that PfHsp40 and Pfj1 co-localise with and regulate the chaperone activity of PfHsp70-I in P. falciparum. This is the first study to identify and provide evidence for a functional Hsp70-Hsp40 partnership in P. falciparum, and provides a platform for future studies to elucidate the importance of these chaperone partnerships in the establishment and survival of the parasite in the intraerythrocytic-stages of development.
- Full Text:
- Date Issued: 2009
- Authors: Botha, Melissa
- Date: 2009
- Subjects: Heat shock proteins Plasmodium falciparum Protein folding Molecular chaperones Malaria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3938 , http://hdl.handle.net/10962/d1003997
- Description: Central to this research, 40 kDa Heat shock proteins (Hsp40s) are known to partner (or cochaperone) 70 kDa Heat shock proteins (Hsp70s), facilitating the selection and transfer of protein substrate to Hsp70 and the stimulation of the protein folding ability of Hsp70. Members of the diverse Hsp70-Hsp40 protein complement of Plasmodium falciparum have been implicated in the cytoprotection of this malaria parasite, and are thought to facilitate the protein folding, assembly and translocation tasks required by the parasite to commandeer the infected human erythrocyte subsequent to invasion. In particular, the parasite has evolved an expanded and specialised 43- member suite of Hsp40 proteins, 19 of which bear an identifiable export motif for secretion into the infected erythrocyte cytoplasm where they potentially interact with human Hsp70. Although type I Hsp40 proteins are representative of typical regulators of Hsp70 activity, only two of these proteins are apparent in the parasite’s Hsp40 complement. These include a characteristic type I Hsp40 termed PfHsp40, and a larger, atypical type I Hsp40 termed Pfj1. Both Hsp40 proteins are predicted to be parasite-resident and are most likely to facilitate the co-chaperone regulation of the highly abundant and stress-inducible Hsp70 homolog, PfHsp70-I. In this work, the co-chaperone functionality of PfHsp40 and Pfj1 was elucidated using in vivo and in vitro assays. Purified recombinant PfHsp40 was shown to stimulate the ATPase activity of PfHsp70-I in in vitro single turnover and steady state ATPase assays, and co-operate with PfHsp70-I in in vitro aggregation suppression assays. In these in vitro assays, heterologous partnerships could be demonstrated between PfHsp70-I and the human Hsp40, Hsj1a, and human Hsp70 and PfHsp40, suggesting a common mode of Hsp70-Hsp40 interaction in the parasite and host organism. The functionality of the signature Hsp40 domain, the Jdomain, of Pfj1 was demonstrated by its ability to replace the equivalent domain of the A. tumefaciens Hsp40, Agt DnaJ, in interactions with the prokaryotic Hsp70, DnaK, in the thermosensitive dnaJ cbpA E. coli OD259 deletion strain. An H33Q mutation introduced into the invariant and crucial HPD tripeptide motif abrogated the functionality of the J-domain in the in vivo complementation system. These findings provide the first evidence for the conservation of the prototypical mode of J-domain based interaction of Hsp40 with Hsp70 in P. falciparum. Immunofluorescence staining revealed the localisation of PfHsp40 to the parasite cytoplasm, and Pfj1 to the parasite cytoplasm and nucleus in cultured intraerythrocytic stage P. falciparum parasites. PfHsp70-I was also shown to localise to the parasite cytoplasm and nucleus in these stages, consistent with the literature. Overall we propose that PfHsp40 and Pfj1 co-localise with and regulate the chaperone activity of PfHsp70-I in P. falciparum. This is the first study to identify and provide evidence for a functional Hsp70-Hsp40 partnership in P. falciparum, and provides a platform for future studies to elucidate the importance of these chaperone partnerships in the establishment and survival of the parasite in the intraerythrocytic-stages of development.
- Full Text:
- Date Issued: 2009
Evaluation of a plant-herbivore system in determining potential efficacy of a candidate biological control agent, cornops aquaticum for water hyacinth, eichhornia crassipes
- Authors: Bownes, Angela
- Date: 2009
- Subjects: Water hyacinth -- Control -- South Africa , Eichhornia crassipedes , Pontederiaceae , Grasshoppers , Biological pest control agents -- South Africa , Weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5687 , http://hdl.handle.net/10962/d1005373
- Description: Water hyacinth, Eichhornia crassipes Mart. Solms-Laubach (Pontederiaceae), a freefloating aquatic macrophyte of Neotropical origin, was introduced into South Africa as an ornamental aquarium plant in the early 1900’s. By the 1970’s it had reached pest proportions in dams and rivers around the country. Due to the sustainability, cost efficiency and low environmental risk associated with biological control, this has been a widely used method in an attempt to reduce infestations to below the threshold where they cause economic and ecological damage. To date, five arthropod and one pathogen biocontrol agents have been introduced for the control of water hyacinth but their impact has been variable. It is believed that their efficacy is hampered by the presence of highly eutrophic systems in South Africa in which plant growth is prolific and the negative effects of herbivory are therefore mitigated. It is for these reasons that new, potentially more damaging biocontrol agents are being considered for release. The water hyacinth grasshopper, Cornops aquaticum Brüner (Orthoptera: Acrididae), which is native to South America and Mexico, was brought into quarantine in Pretoria, South Africa in 1995. Although the grasshopper was identified as one of the most damaging insects associated with water hyacinth in its native range, it has not been considered as a biocontrol agent for water hyacinth anywhere else in the world. After extensive host-range testing which revealed it to be safe for release, a release permit for this candidate agent was issued in 2007. However, host specificity testing is no longer considered to be the only important component of pre-release screening of candidate biocontrol agents. Investigating biological and ecological aspects of the plant-herbivore system that will assist in determination of potential establishment, efficacy and the ability to build up good populations in the recipient environment are some of the important factors. This thesis is a pre-release evaluation of C. aquaticum to determine whether it is sufficiently damaging to water hyacinth to warrant its release. It investigated interactions between the grasshopper and water hyacinth under a range of nutrient conditions found in South African water bodies as well as the impact of the grasshopper on the competitive performance of water hyacinth. Both plant growth rates and the response of water hyacinth to herbivory by the grasshopper were influenced by nutrient availability to the plants. The ability of water hyacinth to compensate for loss of tissue through herbivory was greater under eutrophic nutrient conditions. However, a negative linear relationship was found between grasshopper biomass and water hyacinth performance parameters such as biomass accumulation and leaf production, even under eutrophic conditions. Water hyacinth’s compensatory ability in terms of its potential to mitigate to detrimental effects of insect feeding was dependent on the amount of damage caused by herbivory by the grasshopper. Plant biomass and the competitive ability of water hyacinth in relation to another freefloating aquatic weed species were reduced by C. aquaticum under eutrophic nutrient conditions, in a short space of time. It was also found that grasshopper feeding and characteristics related to their population dynamics such as fecundity and survival were significantly influenced by water nutrient availability and that environmental nutrient availability will influence the control potential of this species should it be released in South Africa. Cornops aquaticum shows promise as a biocontrol agent for water hyacinth but additional factors that were not investigated in this study such as compatibility with the South African climate and the current water hyacinth biocontrol agents need to be combined with these data to make a decision on its release. Possible management options for this species if it is to be introduced into South Africa are discussed.
- Full Text:
- Date Issued: 2009
- Authors: Bownes, Angela
- Date: 2009
- Subjects: Water hyacinth -- Control -- South Africa , Eichhornia crassipedes , Pontederiaceae , Grasshoppers , Biological pest control agents -- South Africa , Weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5687 , http://hdl.handle.net/10962/d1005373
- Description: Water hyacinth, Eichhornia crassipes Mart. Solms-Laubach (Pontederiaceae), a freefloating aquatic macrophyte of Neotropical origin, was introduced into South Africa as an ornamental aquarium plant in the early 1900’s. By the 1970’s it had reached pest proportions in dams and rivers around the country. Due to the sustainability, cost efficiency and low environmental risk associated with biological control, this has been a widely used method in an attempt to reduce infestations to below the threshold where they cause economic and ecological damage. To date, five arthropod and one pathogen biocontrol agents have been introduced for the control of water hyacinth but their impact has been variable. It is believed that their efficacy is hampered by the presence of highly eutrophic systems in South Africa in which plant growth is prolific and the negative effects of herbivory are therefore mitigated. It is for these reasons that new, potentially more damaging biocontrol agents are being considered for release. The water hyacinth grasshopper, Cornops aquaticum Brüner (Orthoptera: Acrididae), which is native to South America and Mexico, was brought into quarantine in Pretoria, South Africa in 1995. Although the grasshopper was identified as one of the most damaging insects associated with water hyacinth in its native range, it has not been considered as a biocontrol agent for water hyacinth anywhere else in the world. After extensive host-range testing which revealed it to be safe for release, a release permit for this candidate agent was issued in 2007. However, host specificity testing is no longer considered to be the only important component of pre-release screening of candidate biocontrol agents. Investigating biological and ecological aspects of the plant-herbivore system that will assist in determination of potential establishment, efficacy and the ability to build up good populations in the recipient environment are some of the important factors. This thesis is a pre-release evaluation of C. aquaticum to determine whether it is sufficiently damaging to water hyacinth to warrant its release. It investigated interactions between the grasshopper and water hyacinth under a range of nutrient conditions found in South African water bodies as well as the impact of the grasshopper on the competitive performance of water hyacinth. Both plant growth rates and the response of water hyacinth to herbivory by the grasshopper were influenced by nutrient availability to the plants. The ability of water hyacinth to compensate for loss of tissue through herbivory was greater under eutrophic nutrient conditions. However, a negative linear relationship was found between grasshopper biomass and water hyacinth performance parameters such as biomass accumulation and leaf production, even under eutrophic conditions. Water hyacinth’s compensatory ability in terms of its potential to mitigate to detrimental effects of insect feeding was dependent on the amount of damage caused by herbivory by the grasshopper. Plant biomass and the competitive ability of water hyacinth in relation to another freefloating aquatic weed species were reduced by C. aquaticum under eutrophic nutrient conditions, in a short space of time. It was also found that grasshopper feeding and characteristics related to their population dynamics such as fecundity and survival were significantly influenced by water nutrient availability and that environmental nutrient availability will influence the control potential of this species should it be released in South Africa. Cornops aquaticum shows promise as a biocontrol agent for water hyacinth but additional factors that were not investigated in this study such as compatibility with the South African climate and the current water hyacinth biocontrol agents need to be combined with these data to make a decision on its release. Possible management options for this species if it is to be introduced into South Africa are discussed.
- Full Text:
- Date Issued: 2009
Development of a process for the preparation of linalool from CIS-2-pinanol
- Authors: Buddoo, Subash Ramnarain
- Date: 2009
- Subjects: Odors , Perfumes -- History , Perfumes -- Formulae , Fermentation
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10425 , http://hdl.handle.net/10948/d1016219
- Description: Linalool is a key intermediate for the production of important fragrance chemicals such as geraniol, nerol, geranial, and neral. Linalool can be produced via a two-step process from α-pinene which is a major component of crude sulphated turpentine (CST) a foul-smelling, volatile waste product of the pulp and paper industry. The key step in this process is the pyrolysis step which involves the isomerisation of cis-2-pinanol to linalool and requires high temperatures (600-650°C) and is not very selective due to the decomposition of the product itself under these conditions. A client of the CSIR, Teubes Pty. Ltd., is a manufacturer of flavour and fragrance compounds for the local and international fragrance market and expressed an interest in producing linalool since the company would then gain access to other valuable fragrance chemicals via relatively simple processes. Earlier work conducted by AECI, R & D did not meet with much success since the selectivity to linalool was very poor and the process could hardly be deemed as scalable. The main objective of this project was therefore to develop a process for the selective isomerisation of cis-2-pinanol to linalool with minimum by-product formation and using process equipment that could be scaled to full-scale production. Since cis-2- pinanol could not be purchased in sufficient quantities for process development, a process had to be developed for the bench-scale preparation of kilogram quantities of cis-2-pinanol from α-pinene obtained from the client. Although this synthesis formed a minor part of this investigation, several process improvements and innovations were introduced to produce high quality cis-2-pinanol, in very good yields at kilogram scale. A major part of this investigation was the design and set up of a pyrolyis rig capable of operating at elevated temperatures (400 - 750°C) for the evaluation of various process parameters. Various vaporizer, reactor, and condensation systems were evaluated for their ability to cope with the demanding conditions on a consistent basis. The initial part of the investigation was a screening exercise to evaluate various process parameters as well as solvents, materials of construction, catalysts, etc. A comprehensive statistical design was also conducted to determine the critical process parameters and the model obtained was used to predict the optimum conditions required for the preparation of in-specification product on a consistent basis. These conditions were used in the preparation of a 1kg sample which was required by theclient for market evaluation purposes. The use of a novel microreactor system was also evaluated for the pinanol pyrolysis reaction. To our knowledge, this is the first time that a microreactor has been successfully used for this type of reaction in the Fragrance industry and a patent application is being filed by the CSIR. The kinetics of the reaction in both the tubular reactor system and the microreactor system was investigated. Computer modelling studies on both the systems were also conducted. The raw material cost to produce a kilogram of linalool is $1.40. There is a significant margin of 60.8 percent between the raw material cost of linalool and the current selling price ($3.57/kg). This clearly indicates that the project is potentially feasible from an economic point of view and we can now proceed with confidence to the next stage which is the engineering design, building and commissioning of the large scale pyrolysis rig. The rest of the process steps will be conducted on existing equipment currently present at the CSIR’s large scale facility (Imbiza in Isando, Gauteng).
- Full Text:
- Date Issued: 2009
- Authors: Buddoo, Subash Ramnarain
- Date: 2009
- Subjects: Odors , Perfumes -- History , Perfumes -- Formulae , Fermentation
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10425 , http://hdl.handle.net/10948/d1016219
- Description: Linalool is a key intermediate for the production of important fragrance chemicals such as geraniol, nerol, geranial, and neral. Linalool can be produced via a two-step process from α-pinene which is a major component of crude sulphated turpentine (CST) a foul-smelling, volatile waste product of the pulp and paper industry. The key step in this process is the pyrolysis step which involves the isomerisation of cis-2-pinanol to linalool and requires high temperatures (600-650°C) and is not very selective due to the decomposition of the product itself under these conditions. A client of the CSIR, Teubes Pty. Ltd., is a manufacturer of flavour and fragrance compounds for the local and international fragrance market and expressed an interest in producing linalool since the company would then gain access to other valuable fragrance chemicals via relatively simple processes. Earlier work conducted by AECI, R & D did not meet with much success since the selectivity to linalool was very poor and the process could hardly be deemed as scalable. The main objective of this project was therefore to develop a process for the selective isomerisation of cis-2-pinanol to linalool with minimum by-product formation and using process equipment that could be scaled to full-scale production. Since cis-2- pinanol could not be purchased in sufficient quantities for process development, a process had to be developed for the bench-scale preparation of kilogram quantities of cis-2-pinanol from α-pinene obtained from the client. Although this synthesis formed a minor part of this investigation, several process improvements and innovations were introduced to produce high quality cis-2-pinanol, in very good yields at kilogram scale. A major part of this investigation was the design and set up of a pyrolyis rig capable of operating at elevated temperatures (400 - 750°C) for the evaluation of various process parameters. Various vaporizer, reactor, and condensation systems were evaluated for their ability to cope with the demanding conditions on a consistent basis. The initial part of the investigation was a screening exercise to evaluate various process parameters as well as solvents, materials of construction, catalysts, etc. A comprehensive statistical design was also conducted to determine the critical process parameters and the model obtained was used to predict the optimum conditions required for the preparation of in-specification product on a consistent basis. These conditions were used in the preparation of a 1kg sample which was required by theclient for market evaluation purposes. The use of a novel microreactor system was also evaluated for the pinanol pyrolysis reaction. To our knowledge, this is the first time that a microreactor has been successfully used for this type of reaction in the Fragrance industry and a patent application is being filed by the CSIR. The kinetics of the reaction in both the tubular reactor system and the microreactor system was investigated. Computer modelling studies on both the systems were also conducted. The raw material cost to produce a kilogram of linalool is $1.40. There is a significant margin of 60.8 percent between the raw material cost of linalool and the current selling price ($3.57/kg). This clearly indicates that the project is potentially feasible from an economic point of view and we can now proceed with confidence to the next stage which is the engineering design, building and commissioning of the large scale pyrolysis rig. The rest of the process steps will be conducted on existing equipment currently present at the CSIR’s large scale facility (Imbiza in Isando, Gauteng).
- Full Text:
- Date Issued: 2009
Factors influencing survivor qualities after downsizing
- Authors: Chipunza, Crispen
- Date: 2009
- Subjects: Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9381 , http://hdl.handle.net/10948/1219 , Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Description: Today organisations all over the world have to cope with the ever-increasing rate of local and global change. Those in developing countries have to cope with the inefficiencies engendered by state-led economic, developmental and political strategies, such as new government regulations. These have had an impact on the management of human resources and are exemplified by an increasing adoption of strategies meant to reduce pressure on costs and margins. An increasing popular management response to these challenges has been to engage in some form of organisational restructuring such as downsizing. Often employees who remain (survivors) after downsizing are not given much attention, yet the achievement of new strategic goals depends on the survivors having positive attitudes, relentless commitment and high motivation. Research indicates that employees who are motivated and committed contribute vastly to the financial-bottom-line of the organisation. Therefore, downsizing organisations should continuously search for ways to increase such qualities among their survivors. The objective of this study was to identify the factors that influence the attitudes, commitment and motivation of survivors in a developing economy with a volatile environment. To achieve this objective, a theoretical survivor quality model was presented. In order to present the model, firstly, a literature survey on the importance of survivor quality in terms of attitudes, commitment, and motivation among survivors was conducted. Secondly, literature survey pertaining to the drivers of survivor quality was done, and thirdly, literature dealing with strategies to deal with survivor quality was surveyed. The theoretical survivor quality model was used to compile the research instrument that determined the attitudinal, commitment and motivational levels of survivors, how the three constructs are related after downsizing, as well as the factors influencing the observed levels. The questionnaire was randomly distributed among survivors in the selected manufacturing organisations in Zimbabwe. The empirical results obtained from the study showed that survivors in a developing economy with a volatile environment had moderate levels of attitudes, commitment ad motivation. Two categories of factors were identified as important in influencing these levels. They were downsizing strategy and demographic factors. The downsizing strategy factors were communication and victim support, while education, age, and number of years employed emerged as the demographic factors. The study further highlighted that older survivors with less education contributed more to the moderate levels of attitude, commitment and motivation observed. The study highlights that these variables must be taken into consideration when implementing downsizing in an economically volatile environment in order to manage survivor quality. A further point emanating from the study is that prior to downsizing, organisations should adopt effective communication strategies throughout the process. The key factors identified as influencing survivor quality in this study were integrated into the survivor quality model which can be used by other organisations in a similar context to manage survivor quality in order to increase their efficiency, effectiveness, iv and competitive advantage after downsizing.
- Full Text:
- Date Issued: 2009
- Authors: Chipunza, Crispen
- Date: 2009
- Subjects: Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9381 , http://hdl.handle.net/10948/1219 , Downsizing of organizations -- South Africa , Organizational change -- South Africa , Cost control , Unemployment -- Psychological aspects
- Description: Today organisations all over the world have to cope with the ever-increasing rate of local and global change. Those in developing countries have to cope with the inefficiencies engendered by state-led economic, developmental and political strategies, such as new government regulations. These have had an impact on the management of human resources and are exemplified by an increasing adoption of strategies meant to reduce pressure on costs and margins. An increasing popular management response to these challenges has been to engage in some form of organisational restructuring such as downsizing. Often employees who remain (survivors) after downsizing are not given much attention, yet the achievement of new strategic goals depends on the survivors having positive attitudes, relentless commitment and high motivation. Research indicates that employees who are motivated and committed contribute vastly to the financial-bottom-line of the organisation. Therefore, downsizing organisations should continuously search for ways to increase such qualities among their survivors. The objective of this study was to identify the factors that influence the attitudes, commitment and motivation of survivors in a developing economy with a volatile environment. To achieve this objective, a theoretical survivor quality model was presented. In order to present the model, firstly, a literature survey on the importance of survivor quality in terms of attitudes, commitment, and motivation among survivors was conducted. Secondly, literature survey pertaining to the drivers of survivor quality was done, and thirdly, literature dealing with strategies to deal with survivor quality was surveyed. The theoretical survivor quality model was used to compile the research instrument that determined the attitudinal, commitment and motivational levels of survivors, how the three constructs are related after downsizing, as well as the factors influencing the observed levels. The questionnaire was randomly distributed among survivors in the selected manufacturing organisations in Zimbabwe. The empirical results obtained from the study showed that survivors in a developing economy with a volatile environment had moderate levels of attitudes, commitment ad motivation. Two categories of factors were identified as important in influencing these levels. They were downsizing strategy and demographic factors. The downsizing strategy factors were communication and victim support, while education, age, and number of years employed emerged as the demographic factors. The study further highlighted that older survivors with less education contributed more to the moderate levels of attitude, commitment and motivation observed. The study highlights that these variables must be taken into consideration when implementing downsizing in an economically volatile environment in order to manage survivor quality. A further point emanating from the study is that prior to downsizing, organisations should adopt effective communication strategies throughout the process. The key factors identified as influencing survivor quality in this study were integrated into the survivor quality model which can be used by other organisations in a similar context to manage survivor quality in order to increase their efficiency, effectiveness, iv and competitive advantage after downsizing.
- Full Text:
- Date Issued: 2009
The development and evaluation of a programme to promote sensitive pscyhotherapeutic practice with gay men and lesbians
- Authors: Coetzee, Catherine Ann
- Date: 2009
- Subjects: Psychotherapy -- Practice -- South Africa Psychoanalysis and homosexuality -- South Africa Homosexuality -- Social aspects -- South Africa Homosexuality -- Psychological aspects -- South Africa Psychotherapy -- Moral and ethical aspects -- South Africa Psychologists -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2952 , http://hdl.handle.net/10962/d1002461
- Description: Clinical psychology’s relevance and future viability depend on its ability to render services that are relevant and sensitive to multicultural and minority issues. Lesbian, gay, bisexual and transgendered people are one such group that professional psychology – both in South Africa and abroad - has identified as having unique treatment needs for which psychologists require specialised knowledge and skills in order to render appropriate treatment. Competence to treat non-heterosexual patients has been framed in terms of a gay affirmative paradigm which has as its basic tenet the recognition that same-gender orientation is not pathological but rather a healthy alternative to heterosexuality. From this perspective being “gay friendly” or “gay accepting” is not enough. To implement a gay affirmative approach in practice, practitioners must have resolved their possible prejudice and heterosexist bias and have the requisite knowledge of concerns unique to lesbian, gay, and bisexual (LGB) individuals to be able to apply their skills in a culturally sensitive manner. Although more American post-graduate psychology programmes are addressing sexual diversity, their failure to produce psychologists who feel competent to treat lesbian/gay or bisexual individuals has highlighted the need to develop effective training strategies based on empirical nvestigation. The dearth of comparable data about local South African psychology training prompted this inquiry which had four broad aims namely, (i) to establish to what extent trainees’ prior training had equipped them with the knowledge, awareness, and skills to approach their work with non-heterosexual patients in a gay affirmative manner, and (ii) to implement and (iii) to evaluate to what extent a brief structured training programme is effective in engaging the trainees; in increasing knowledge, in raising awareness, and in changing specific attitudes and imparting specific skills required for treating lesbian and gay patients.; and (iv) what, if any, recommendations should be made for the future with respect to training of sychologists in this area? The field of sexual orientation research has been expanded to include issues pertaining to bisexual, transgendered and intersexed people, but serious time constraints meant that issues pertaining to these groups could not be addressed in depth. Although the exclusion of these groups is problematic and may be seen as reinforcing their invisibility, it was decided to focus primarily on gay and lesbian issues s an introduction to same-sex orientation. It is envisaged that bisexual and transgender issues would be dealt with in depth in more advanced training. Nine trainee psychologists employed at hospitals in the greater Cape Town area volunteered to participate in the programme which comprised a series of two-hour experiential workshops offered once a week over six weeks. The study employed both quantitative and qualitative data analysis methods. The first stage entailed gathering information to better understand trainees’ existing level of competence. Individual interviews were conducted prior to the course to obtain data about their attitudes and perceptions regarding the need for such specialised training, and how qualified they considered themselves to be to treat LGB patients, and their experience in this regard. For the purpose of the over-all analysis information was also gathered about pertinent personal and social characteristics of the trainees, as well as their contact with lesbian/gay persons. In addition, an attitude survey and the Lesbian, Gay, and Bisexual Counselling Self-efficacy Scale (LGB-CSI) were administered to obtain benchmarks against which change could be measured. The second stage involved the implementation of the educational programme and gathering information about trainees’ responses to its various components. This stage concentrated on discovering how individual trainees reacted to material on lesbian, gay, and bisexual issues and how they used the programme to improve their self-awareness and skills. The results indicate that local psychology training might not address same-gender orientation adequately, thus reinforcing trainees’ belief that sexual orientation is irrelevant, and that their generalist training equips them to work with gay/lesbian/bisexual patients. While the training strengthened existing positive attitudes, it was less effective in changing blatant antigay prejudice. However, both quantitative and qualitative data suggest that the programme increased individuals’ awareness and insight into their previously unrecognised heterosexist biases and created greater understanding of the effects of stigmatisation on sexual minority individuals. In addition, the training increased trainee’s sense of competence to provide affirmative treatment as evidenced by the significant differences between the pre- and post-training mean scores on the Relationship, Knowledge, and Advocacy Scales and between the mid- and post-training means scores on the Assessment and Awareness Scales of the LGB-CSI. Despite the limited generalisability of these findings on account of possible sampling bias, the need and value of such training was confirmed by trainees’ recommendation that this programme should be a mandatory offering in the first year of clinical psychology training.
- Full Text:
- Date Issued: 2009
- Authors: Coetzee, Catherine Ann
- Date: 2009
- Subjects: Psychotherapy -- Practice -- South Africa Psychoanalysis and homosexuality -- South Africa Homosexuality -- Social aspects -- South Africa Homosexuality -- Psychological aspects -- South Africa Psychotherapy -- Moral and ethical aspects -- South Africa Psychologists -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2952 , http://hdl.handle.net/10962/d1002461
- Description: Clinical psychology’s relevance and future viability depend on its ability to render services that are relevant and sensitive to multicultural and minority issues. Lesbian, gay, bisexual and transgendered people are one such group that professional psychology – both in South Africa and abroad - has identified as having unique treatment needs for which psychologists require specialised knowledge and skills in order to render appropriate treatment. Competence to treat non-heterosexual patients has been framed in terms of a gay affirmative paradigm which has as its basic tenet the recognition that same-gender orientation is not pathological but rather a healthy alternative to heterosexuality. From this perspective being “gay friendly” or “gay accepting” is not enough. To implement a gay affirmative approach in practice, practitioners must have resolved their possible prejudice and heterosexist bias and have the requisite knowledge of concerns unique to lesbian, gay, and bisexual (LGB) individuals to be able to apply their skills in a culturally sensitive manner. Although more American post-graduate psychology programmes are addressing sexual diversity, their failure to produce psychologists who feel competent to treat lesbian/gay or bisexual individuals has highlighted the need to develop effective training strategies based on empirical nvestigation. The dearth of comparable data about local South African psychology training prompted this inquiry which had four broad aims namely, (i) to establish to what extent trainees’ prior training had equipped them with the knowledge, awareness, and skills to approach their work with non-heterosexual patients in a gay affirmative manner, and (ii) to implement and (iii) to evaluate to what extent a brief structured training programme is effective in engaging the trainees; in increasing knowledge, in raising awareness, and in changing specific attitudes and imparting specific skills required for treating lesbian and gay patients.; and (iv) what, if any, recommendations should be made for the future with respect to training of sychologists in this area? The field of sexual orientation research has been expanded to include issues pertaining to bisexual, transgendered and intersexed people, but serious time constraints meant that issues pertaining to these groups could not be addressed in depth. Although the exclusion of these groups is problematic and may be seen as reinforcing their invisibility, it was decided to focus primarily on gay and lesbian issues s an introduction to same-sex orientation. It is envisaged that bisexual and transgender issues would be dealt with in depth in more advanced training. Nine trainee psychologists employed at hospitals in the greater Cape Town area volunteered to participate in the programme which comprised a series of two-hour experiential workshops offered once a week over six weeks. The study employed both quantitative and qualitative data analysis methods. The first stage entailed gathering information to better understand trainees’ existing level of competence. Individual interviews were conducted prior to the course to obtain data about their attitudes and perceptions regarding the need for such specialised training, and how qualified they considered themselves to be to treat LGB patients, and their experience in this regard. For the purpose of the over-all analysis information was also gathered about pertinent personal and social characteristics of the trainees, as well as their contact with lesbian/gay persons. In addition, an attitude survey and the Lesbian, Gay, and Bisexual Counselling Self-efficacy Scale (LGB-CSI) were administered to obtain benchmarks against which change could be measured. The second stage involved the implementation of the educational programme and gathering information about trainees’ responses to its various components. This stage concentrated on discovering how individual trainees reacted to material on lesbian, gay, and bisexual issues and how they used the programme to improve their self-awareness and skills. The results indicate that local psychology training might not address same-gender orientation adequately, thus reinforcing trainees’ belief that sexual orientation is irrelevant, and that their generalist training equips them to work with gay/lesbian/bisexual patients. While the training strengthened existing positive attitudes, it was less effective in changing blatant antigay prejudice. However, both quantitative and qualitative data suggest that the programme increased individuals’ awareness and insight into their previously unrecognised heterosexist biases and created greater understanding of the effects of stigmatisation on sexual minority individuals. In addition, the training increased trainee’s sense of competence to provide affirmative treatment as evidenced by the significant differences between the pre- and post-training mean scores on the Relationship, Knowledge, and Advocacy Scales and between the mid- and post-training means scores on the Assessment and Awareness Scales of the LGB-CSI. Despite the limited generalisability of these findings on account of possible sampling bias, the need and value of such training was confirmed by trainees’ recommendation that this programme should be a mandatory offering in the first year of clinical psychology training.
- Full Text:
- Date Issued: 2009
An investigation into the use of guidelines and patterns in the interaction design process
- Authors: Cowley, Niel Lester Orr
- Date: 2009
- Subjects: Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10466 , http://hdl.handle.net/10948/1062 , Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Description: Design guidelines are used in interaction design (IxD) for physical design and for evaluating the usability of designs and interactive products. Guidelines are widely used for physical design and evaluation, but have a number of problems. IxD patterns have been proposed as an alternative to guidelines, as they are claimed to have several advantages over guidelines. A small number of empirical studies provide evidence that patterns are beneficial when used in IxD. Additional research on the usefulness of IxD patterns is required. The primary research question investigated in this thesis was thus: How useful are IxD patterns as physical design and evaluation aids in IxD, as compared to design guidelines? The role of guidelines and patterns as design and evaluation aids in IxD was investigated and a comparison of guidelines and patterns, based on a set of guideline and pattern properties, was conducted. The concept of pattern and guideline usefulness was explored and a research agenda for guidelines and patterns was identified, together with a set of research questions for an empirical study. The empirical study of the use of patterns for evaluation, redesign and new design, as compared to guidelines, was conducted at the Nelson Mandela Metropolitan University in 2004. The participants were a purposive sample of post-graduate Computing students, who were regarded as novice interaction designers. Two equivalent groups were formed, one that used patterns and one that used guidelines. Patterns were found to be as useful as guidelines when used as evaluation aids. Guidelines and patterns were identified as effective tools for identifying and explaining usability issues and design features. Best-effort matched sets of guidelines and patterns produced substantially different result sets when used to identify issues and features, with fairly low overlap. A substantial evaluator effect was observed for the use of guidelines and patterns for evaluation, and the results obtained were similar to those obtained by Molich et al. in their Comparative Usability Evaluation (CUE) studies. There was no statistically significant difference between the effectiveness of guidelines and patterns for evaluation. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for evaluation. Guidelines and patterns were found to be used in similar ways for evaluation. Patterns were found to be more effective than guidelines for redesign. Patterns were found to be as useful as guidelines when used for new design. There was no statistically significant difference between the effectiveness of guidelines and patterns for new design. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for redesign and new design. Guidelines and patterns were found to be used in similar ways for design. There was no statistically significant difference between the perceived usefulness of the format, content, ease of learning, and usefulness as personal and shared design languages, of guidelines and patterns. Both participant groups were equally agreeable to using guidelines and patterns in the future. The perceived usefulness of pattern collections was found to depend on the usability of the collection interface and the content quality of the patterns. The results of the empirical study thus provided empirical evidence that patterns were as useful as guidelines for evaluation and new design, and were perceived as positively as guidelines were. Patterns were found to be superior to guidelines for redesign. Patterns can therefore be used with a measure of confidence as early stage design aids for physical design and evaluation in the future. In addition to these findings, a number of opportunities for further research were identified.
- Full Text:
- Date Issued: 2009
- Authors: Cowley, Niel Lester Orr
- Date: 2009
- Subjects: Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10466 , http://hdl.handle.net/10948/1062 , Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Description: Design guidelines are used in interaction design (IxD) for physical design and for evaluating the usability of designs and interactive products. Guidelines are widely used for physical design and evaluation, but have a number of problems. IxD patterns have been proposed as an alternative to guidelines, as they are claimed to have several advantages over guidelines. A small number of empirical studies provide evidence that patterns are beneficial when used in IxD. Additional research on the usefulness of IxD patterns is required. The primary research question investigated in this thesis was thus: How useful are IxD patterns as physical design and evaluation aids in IxD, as compared to design guidelines? The role of guidelines and patterns as design and evaluation aids in IxD was investigated and a comparison of guidelines and patterns, based on a set of guideline and pattern properties, was conducted. The concept of pattern and guideline usefulness was explored and a research agenda for guidelines and patterns was identified, together with a set of research questions for an empirical study. The empirical study of the use of patterns for evaluation, redesign and new design, as compared to guidelines, was conducted at the Nelson Mandela Metropolitan University in 2004. The participants were a purposive sample of post-graduate Computing students, who were regarded as novice interaction designers. Two equivalent groups were formed, one that used patterns and one that used guidelines. Patterns were found to be as useful as guidelines when used as evaluation aids. Guidelines and patterns were identified as effective tools for identifying and explaining usability issues and design features. Best-effort matched sets of guidelines and patterns produced substantially different result sets when used to identify issues and features, with fairly low overlap. A substantial evaluator effect was observed for the use of guidelines and patterns for evaluation, and the results obtained were similar to those obtained by Molich et al. in their Comparative Usability Evaluation (CUE) studies. There was no statistically significant difference between the effectiveness of guidelines and patterns for evaluation. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for evaluation. Guidelines and patterns were found to be used in similar ways for evaluation. Patterns were found to be more effective than guidelines for redesign. Patterns were found to be as useful as guidelines when used for new design. There was no statistically significant difference between the effectiveness of guidelines and patterns for new design. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for redesign and new design. Guidelines and patterns were found to be used in similar ways for design. There was no statistically significant difference between the perceived usefulness of the format, content, ease of learning, and usefulness as personal and shared design languages, of guidelines and patterns. Both participant groups were equally agreeable to using guidelines and patterns in the future. The perceived usefulness of pattern collections was found to depend on the usability of the collection interface and the content quality of the patterns. The results of the empirical study thus provided empirical evidence that patterns were as useful as guidelines for evaluation and new design, and were perceived as positively as guidelines were. Patterns were found to be superior to guidelines for redesign. Patterns can therefore be used with a measure of confidence as early stage design aids for physical design and evaluation in the future. In addition to these findings, a number of opportunities for further research were identified.
- Full Text:
- Date Issued: 2009
Learning, governance and livelihoods : toward adaptive co-management under resource poor conditions in South Africa
- Authors: Cundill, Georgina
- Date: 2009
- Subjects: Natural resources -- Co-management -- South Africa Rural poor -- South Africa Rural development -- South Africa Households -- Economic aspects -- South Africa Sustainable development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4747 , http://hdl.handle.net/10962/d1006961
- Description: Through collaborative monitoring and case study comparison, this thesis explores conceptual and methodological approaches to monitoring transitions toward adaptive co-management. In so doing, a number of knowledge gaps are addressed. Firstly, conceptual and methodological frameworks are developed for monitoring transitions toward adaptive co-management. Secondly, a conceptual and practical approach to monitoring the processes of collaboration and learning is developed and tested. Thirdly, a conceptual and practical approach to monitoring the governance outcomes of adaptive co-management is developed and tested. Fourthly, a conceptual and practical approach to monitoring the livelihood outcomes of adaptive co-management is developed and tested. Based on the outcomes from these four components of the study, this thesis explores the ways in which transitions toward adaptive co-management might be initiated under the resource poor conditions that characterise South Africa's communal areas. The four case studies explored in the study are described as 'resource poor' in terms of institutional capacity, ecosystem productivity and social vulnerability. From a resilience perspective these case studies can be described as being in the re-organisation phase of the adaptive cycle following multiple disturbances over time, largely due to South Africa's historical 'separate development' policies. Scholars have suggested that it is in this re-organisation phase that innovation and novelty might occur. The lens of social learning is applied to analyse collaborative processes within these contexts. Results indicate that the institutional innovation necessary for transitions toward adaptive co-management relies on careful facilitation by an 'honest broker'. Equally important is finding a balance between maintaining key individuals and knowledge holders within decision making networks, and preventing rigidity and vulnerability within communities of practice. The results point to an over simplification in the rhetoric that currently surrounds the learning outcomes of multi level networks. The governance outcomes of the initiatives are explored through the lenses of adaptive governance, social capital, adaptive capacity and self-organisation. Results indicate that under resource poor conditions creating the conditions that facilitate self-organisation is the major challenge facing transformations toward adaptive governance. Long term access to reliable information and capacity and financial support for adaptive management are key constraining variables. The livelihood outcomes of the initiatives are analysed through the lens of resilience and diversification. Results suggest that flexibility, rather than livelihood diversity, is the key livelihood strategy employed by households in situations were options are limited. Interventions that enhance opportunities for households to specialise in situ by actively dealing with structural constraints, such as access to markets and credit, is vital to encouraging innovation during transitions toward adaptive co-management. Based on the results from monitoring, this study identifies key focus areas that require a great deal more attention if transitions toward adaptive co-management are to be initiated under resource poor conditions.
- Full Text:
- Date Issued: 2009
- Authors: Cundill, Georgina
- Date: 2009
- Subjects: Natural resources -- Co-management -- South Africa Rural poor -- South Africa Rural development -- South Africa Households -- Economic aspects -- South Africa Sustainable development -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4747 , http://hdl.handle.net/10962/d1006961
- Description: Through collaborative monitoring and case study comparison, this thesis explores conceptual and methodological approaches to monitoring transitions toward adaptive co-management. In so doing, a number of knowledge gaps are addressed. Firstly, conceptual and methodological frameworks are developed for monitoring transitions toward adaptive co-management. Secondly, a conceptual and practical approach to monitoring the processes of collaboration and learning is developed and tested. Thirdly, a conceptual and practical approach to monitoring the governance outcomes of adaptive co-management is developed and tested. Fourthly, a conceptual and practical approach to monitoring the livelihood outcomes of adaptive co-management is developed and tested. Based on the outcomes from these four components of the study, this thesis explores the ways in which transitions toward adaptive co-management might be initiated under the resource poor conditions that characterise South Africa's communal areas. The four case studies explored in the study are described as 'resource poor' in terms of institutional capacity, ecosystem productivity and social vulnerability. From a resilience perspective these case studies can be described as being in the re-organisation phase of the adaptive cycle following multiple disturbances over time, largely due to South Africa's historical 'separate development' policies. Scholars have suggested that it is in this re-organisation phase that innovation and novelty might occur. The lens of social learning is applied to analyse collaborative processes within these contexts. Results indicate that the institutional innovation necessary for transitions toward adaptive co-management relies on careful facilitation by an 'honest broker'. Equally important is finding a balance between maintaining key individuals and knowledge holders within decision making networks, and preventing rigidity and vulnerability within communities of practice. The results point to an over simplification in the rhetoric that currently surrounds the learning outcomes of multi level networks. The governance outcomes of the initiatives are explored through the lenses of adaptive governance, social capital, adaptive capacity and self-organisation. Results indicate that under resource poor conditions creating the conditions that facilitate self-organisation is the major challenge facing transformations toward adaptive governance. Long term access to reliable information and capacity and financial support for adaptive management are key constraining variables. The livelihood outcomes of the initiatives are analysed through the lens of resilience and diversification. Results suggest that flexibility, rather than livelihood diversity, is the key livelihood strategy employed by households in situations were options are limited. Interventions that enhance opportunities for households to specialise in situ by actively dealing with structural constraints, such as access to markets and credit, is vital to encouraging innovation during transitions toward adaptive co-management. Based on the results from monitoring, this study identifies key focus areas that require a great deal more attention if transitions toward adaptive co-management are to be initiated under resource poor conditions.
- Full Text:
- Date Issued: 2009
Guidelines for the management of patients with diabetes mellitus at health care clinics in the Cacadu region of the Eastern Cape Province of South Africa
- De Mendonça, Hester Magdalena
- Authors: De Mendonça, Hester Magdalena
- Date: 2009
- Subjects: Diabetics -- Treatment -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DCur
- Identifier: vital:10011 , http://hdl.handle.net/10948/1017 , Diabetics -- Treatment -- South Africa -- Eastern Cape
- Description: Diabetes Mellitus (DM) is the new epidemic in the world with 246 million people suffering from the disease at the moment and a projected increase to 380 million in 2025 (IDF, 2007b:36). The developing countries are the most vulnerable. Statistics state that SA and Egypt have the most diabetics on the continent. Globally, each year 3,8 million deaths are attributable to DM (IDF, 2007a). The Department of Health (DOH) and the Cacadu District Municipality (Eastern Cape) are serving a population of 102 721 in the Kouga and Koukamma areas, which covers an area of 5 992 km², with health care. There are 22 clinics with 28 registered nurses for all the clinics and between 3 and 9 lay health workers (LHWs) per clinic. For the purpose of this research study, the persons suffering from DM (±3550) in this area were taken into consideration (Strydom, 2005). DM is a chronic disorder and therefore patients should be able to manage their disease pattern for the rest of their lives (Healthline, 2008, Mbanya, 2006:12). In order to achieve this, continuous and effective patient education by health care providers are necessary. This disease affects more and more people each passing day, because of the rapid westernisation of the South African population, leading to more people attending clinics in the public health sector (Bonnici, 2002:32). There are specific guidelines laid down by the Department of Health (DOH) pertaining to the control and management of DM. Guidelines include the early diagnosis, treatment and patient education regarding DM (Department of Health, 1997, [revised 2004]). Evidence from previous research studies showed that not all registered nurses are aware of these guidelines and most have not been educated regarding the utilisation of these guidelines (O’Brien, van Rooyen & Carlson, 2006:36-40). In the clinics, the health care givers are confronted with a number of difficulties, such as a lack of funds to enable them to order adequate equipment and medicine. Another problem is the migration of registered nurses out of the country thus; there is also a shortage of staff to operate these clinics (Mkhize, 2004). The organisational structure in the clinics does not function optimally and there is a lack of communication between provincial, district and clinic level. Due to the above-mentioned challenges there is also a lack of efficient auditing systems to ensure quality assurance. Furthermore, a knowledge deficit pertaining to DM and the management thereof in all the groups participating in this study, namely the registered nurses, the lay health workers (LHWs) and the diabetic patients was found. The empowerment process of the LHW is not explored fully and therefore not executed to its full potential. To be able to improve the management of DM in this region, it is important to know what the difficulties are that the health care givers as well as the patients experience in relation to this issue. This study therefore explored and described these difficulties. The research was based on a qualitative, quantitative, explorative, descriptive and contextual research design. Health care givers as well as diabetic patients attending clinics in the Cacadu region of the Eastern Cape have been requested to complete questionnaires pertaining to their knowledge of Diabetes Mellitus. The current organisational structure of the provincial department of health was explored and findings analysed using the activities of the management process (Muller, 2006:106). The SA Government is committed to combining the national human resource development strategy with the rapid upgrading of service delivery to all of the nation’s communities. Stemming from this undertaking, suitable members of the community are to be trained as LHWs. LHWs are to play an integral role in strengthening the abilities of the community to empower themselves to participate and take responsibility for their own health and wellness (Department of Health, 2001a:4). From the research, it was found that the above-mentioned national plan had been implemented, but is not functioning at optimum level due to several shortcomings/deficits. Proposed guidelines were therefore designed to address the shortcomings and fragmentation of the plan. As specific knowledge deficits in DM were identified during this research study, general educational guidelines were included for the registered nurses and the diabetic patients. The LHW was identified as an indispensable link in the chain of efficient health care and therefore, specific educational guidelines on DM were generated to prepare her for the role. With her knowledge, insight into DM and the management thereof and newly required skills in educating and supporting of the patient, she could be an asset in the road to optimum self-care for the diabetic patient.
- Full Text:
- Date Issued: 2009
- Authors: De Mendonça, Hester Magdalena
- Date: 2009
- Subjects: Diabetics -- Treatment -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DCur
- Identifier: vital:10011 , http://hdl.handle.net/10948/1017 , Diabetics -- Treatment -- South Africa -- Eastern Cape
- Description: Diabetes Mellitus (DM) is the new epidemic in the world with 246 million people suffering from the disease at the moment and a projected increase to 380 million in 2025 (IDF, 2007b:36). The developing countries are the most vulnerable. Statistics state that SA and Egypt have the most diabetics on the continent. Globally, each year 3,8 million deaths are attributable to DM (IDF, 2007a). The Department of Health (DOH) and the Cacadu District Municipality (Eastern Cape) are serving a population of 102 721 in the Kouga and Koukamma areas, which covers an area of 5 992 km², with health care. There are 22 clinics with 28 registered nurses for all the clinics and between 3 and 9 lay health workers (LHWs) per clinic. For the purpose of this research study, the persons suffering from DM (±3550) in this area were taken into consideration (Strydom, 2005). DM is a chronic disorder and therefore patients should be able to manage their disease pattern for the rest of their lives (Healthline, 2008, Mbanya, 2006:12). In order to achieve this, continuous and effective patient education by health care providers are necessary. This disease affects more and more people each passing day, because of the rapid westernisation of the South African population, leading to more people attending clinics in the public health sector (Bonnici, 2002:32). There are specific guidelines laid down by the Department of Health (DOH) pertaining to the control and management of DM. Guidelines include the early diagnosis, treatment and patient education regarding DM (Department of Health, 1997, [revised 2004]). Evidence from previous research studies showed that not all registered nurses are aware of these guidelines and most have not been educated regarding the utilisation of these guidelines (O’Brien, van Rooyen & Carlson, 2006:36-40). In the clinics, the health care givers are confronted with a number of difficulties, such as a lack of funds to enable them to order adequate equipment and medicine. Another problem is the migration of registered nurses out of the country thus; there is also a shortage of staff to operate these clinics (Mkhize, 2004). The organisational structure in the clinics does not function optimally and there is a lack of communication between provincial, district and clinic level. Due to the above-mentioned challenges there is also a lack of efficient auditing systems to ensure quality assurance. Furthermore, a knowledge deficit pertaining to DM and the management thereof in all the groups participating in this study, namely the registered nurses, the lay health workers (LHWs) and the diabetic patients was found. The empowerment process of the LHW is not explored fully and therefore not executed to its full potential. To be able to improve the management of DM in this region, it is important to know what the difficulties are that the health care givers as well as the patients experience in relation to this issue. This study therefore explored and described these difficulties. The research was based on a qualitative, quantitative, explorative, descriptive and contextual research design. Health care givers as well as diabetic patients attending clinics in the Cacadu region of the Eastern Cape have been requested to complete questionnaires pertaining to their knowledge of Diabetes Mellitus. The current organisational structure of the provincial department of health was explored and findings analysed using the activities of the management process (Muller, 2006:106). The SA Government is committed to combining the national human resource development strategy with the rapid upgrading of service delivery to all of the nation’s communities. Stemming from this undertaking, suitable members of the community are to be trained as LHWs. LHWs are to play an integral role in strengthening the abilities of the community to empower themselves to participate and take responsibility for their own health and wellness (Department of Health, 2001a:4). From the research, it was found that the above-mentioned national plan had been implemented, but is not functioning at optimum level due to several shortcomings/deficits. Proposed guidelines were therefore designed to address the shortcomings and fragmentation of the plan. As specific knowledge deficits in DM were identified during this research study, general educational guidelines were included for the registered nurses and the diabetic patients. The LHW was identified as an indispensable link in the chain of efficient health care and therefore, specific educational guidelines on DM were generated to prepare her for the role. With her knowledge, insight into DM and the management thereof and newly required skills in educating and supporting of the patient, she could be an asset in the road to optimum self-care for the diabetic patient.
- Full Text:
- Date Issued: 2009
Hierarchical spatial structure and levels of resolution of intertidal grazing and their consequences on predictability and stability at small scales
- Authors: Diaz Diaz, Eliecer Rodrigo
- Date: 2009
- Subjects: Marine algae -- Effect of grazing on Shorelines -- South Africa Zostera marina Intertidal ecology Spatial analysis (Statistics)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5707 , http://hdl.handle.net/10962/d1005393
- Description: The aim of this research was to assess three hierarchical aspects of alga-grazer interactions in intertidal communities on a small scale: spatial heterogeneity, grazing effects and spatial stability in grazing effects. First, using semivariograms and cross-semivariograms I observed hierarchical spatial patterns in most algal groups and in grazers. However, these patterns varied with the level on the shore and between shores, suggesting that either human exploitation or wave exposure can be a source of variability. Second, grazing effects were studied using manipulative experiments at different levels on the shore. These revealed significant effects of grazing on the low shore and in tidal pools. Additionally, using a transect of grazer exclusions across the shore, I observed unexpected hierarchical patchiness in the strength of grazing, rather than zonation in its effects. This patchiness varied in time due to different biotic and abiotic factors. In a separate experiment, the effect of mesograzers effects were studied in the upper eulittoral zone under four conditions: burnt open rock (BOR), burnt pools (Bpool), non-burnt open rock (NBOR) and non-burnt pools (NBpool). Additionally, I tested spatial stability in the effects of grazing in consecutive years, using the same plots. I observed great spatial variability in the effects of grazing, but this variability was spatially stable in Bpools and NBOR, meaning deterministic and significant grazing effects in consecutive years on the same plots. Both the significance in grazing effects and spatial stability depended on the level of resolution (species, functional, biomass) at which the algal assemblage was evaluated, suggesting hierarchical variability. In order to be able to predict spatial variability in the effects of grazers in the upper eulittoral zone using biotic and abiotic micro- and macrofactors, a conceptual model was proposed, based on data from several multiple-regressions. This linked the interactions among three elements: idiosyncratic heterogeneity, micro and macrofactors. This suggests that spatial variability can be a product of these factors, while spatial stability can be caused by the same or different combinations of factors. In conclusion, grazing and other ecological phenomena must be studied hierarchically, not only through spatiotemporal scales, but also at different levels of resolution, as these also influence our perception of patterns.
- Full Text:
- Date Issued: 2009
- Authors: Diaz Diaz, Eliecer Rodrigo
- Date: 2009
- Subjects: Marine algae -- Effect of grazing on Shorelines -- South Africa Zostera marina Intertidal ecology Spatial analysis (Statistics)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5707 , http://hdl.handle.net/10962/d1005393
- Description: The aim of this research was to assess three hierarchical aspects of alga-grazer interactions in intertidal communities on a small scale: spatial heterogeneity, grazing effects and spatial stability in grazing effects. First, using semivariograms and cross-semivariograms I observed hierarchical spatial patterns in most algal groups and in grazers. However, these patterns varied with the level on the shore and between shores, suggesting that either human exploitation or wave exposure can be a source of variability. Second, grazing effects were studied using manipulative experiments at different levels on the shore. These revealed significant effects of grazing on the low shore and in tidal pools. Additionally, using a transect of grazer exclusions across the shore, I observed unexpected hierarchical patchiness in the strength of grazing, rather than zonation in its effects. This patchiness varied in time due to different biotic and abiotic factors. In a separate experiment, the effect of mesograzers effects were studied in the upper eulittoral zone under four conditions: burnt open rock (BOR), burnt pools (Bpool), non-burnt open rock (NBOR) and non-burnt pools (NBpool). Additionally, I tested spatial stability in the effects of grazing in consecutive years, using the same plots. I observed great spatial variability in the effects of grazing, but this variability was spatially stable in Bpools and NBOR, meaning deterministic and significant grazing effects in consecutive years on the same plots. Both the significance in grazing effects and spatial stability depended on the level of resolution (species, functional, biomass) at which the algal assemblage was evaluated, suggesting hierarchical variability. In order to be able to predict spatial variability in the effects of grazers in the upper eulittoral zone using biotic and abiotic micro- and macrofactors, a conceptual model was proposed, based on data from several multiple-regressions. This linked the interactions among three elements: idiosyncratic heterogeneity, micro and macrofactors. This suggests that spatial variability can be a product of these factors, while spatial stability can be caused by the same or different combinations of factors. In conclusion, grazing and other ecological phenomena must be studied hierarchically, not only through spatiotemporal scales, but also at different levels of resolution, as these also influence our perception of patterns.
- Full Text:
- Date Issued: 2009
From song to literary texts : a study of the influence of isiXhosa lyrics on selected isiXhosa texts
- Authors: Dlepu, Siziwe Everrette
- Date: 2009
- Subjects: Xhosa (African people) -- Songs and music -- Texts , Folk songs, Xhosa -- South Africa , Xhosa (African people) -- Music , Xhosa -- Music
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8460 , http://hdl.handle.net/10948/943 , Xhosa (African people) -- Songs and music -- Texts , Folk songs, Xhosa -- South Africa , Xhosa (African people) -- Music , Xhosa -- Music
- Description: Songs play a vital role in the everyday life of the AmaXhosa. Each and every occasion or gathering is accompanied by singing. Their anger or pain, sorrow or joy is reflected in their singing. Although these songs are composed for social purposes and entertainment, they are also educational. Songs may be composed and sung to comment on political affairs, complain against the abuse of power by the authorities, declare war, protest, praise a hero, encourage working together and ridicule the foolishness of someone. Vocabulary and diction used in the composition of these songs, relays the message in a clever and witty style. Since the AmaXhosa are intellectuals, irony and satire are used. The satirical or ironical songs hide the meaning and the listener must unravel the real meaning. AmaXhosa singing, chanting and dancing is accompanied by instruments. These instruments add more rhythm to the dance.The AmaXhosa use anything at their disposal when carving their instruments. Their songs may be accompanied by the beating of cow-hide drums, blowing of reed-pipe whistles, animal horns, beating of sticks and hand-clapping. The most important instrument the AmaXhosa use is the human voice. They are experts in humming, gruff singing and whistling. The songs of the AmaXhosa encourage togetherness. When one composes a song, one does not express one’s own feelings, but also the feelings of the community. The AmaXhosa songs are about participation so group singing and dancing is encouraged. Everyone participates either by singing, dancing or clapping. x Respect is the central core of the AmaXhosa songs. That is why the songs are composed according to age groups and sex. Instruments are also used according to ages and sex. Written texts are also a tool to educate the reader. The writers have decided to include songs in their writings to act as a form of entertainment and education. Although some songs lack the hallmarks of a traditional song, they communicate the idea or relay the message the writer wants to convey to the reader. Terms: Mock enconuim, the grotesque and the principle of beautiful deformity, anaphoric construction, diction and connotation, authorial comments, the mask-persona form, usurping of authority and reduction of traditional status.
- Full Text:
- Date Issued: 2009
From song to literary texts : a study of the influence of isiXhosa lyrics on selected isiXhosa texts
- Authors: Dlepu, Siziwe Everrette
- Date: 2009
- Subjects: Xhosa (African people) -- Songs and music -- Texts , Folk songs, Xhosa -- South Africa , Xhosa (African people) -- Music , Xhosa -- Music
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8460 , http://hdl.handle.net/10948/943 , Xhosa (African people) -- Songs and music -- Texts , Folk songs, Xhosa -- South Africa , Xhosa (African people) -- Music , Xhosa -- Music
- Description: Songs play a vital role in the everyday life of the AmaXhosa. Each and every occasion or gathering is accompanied by singing. Their anger or pain, sorrow or joy is reflected in their singing. Although these songs are composed for social purposes and entertainment, they are also educational. Songs may be composed and sung to comment on political affairs, complain against the abuse of power by the authorities, declare war, protest, praise a hero, encourage working together and ridicule the foolishness of someone. Vocabulary and diction used in the composition of these songs, relays the message in a clever and witty style. Since the AmaXhosa are intellectuals, irony and satire are used. The satirical or ironical songs hide the meaning and the listener must unravel the real meaning. AmaXhosa singing, chanting and dancing is accompanied by instruments. These instruments add more rhythm to the dance.The AmaXhosa use anything at their disposal when carving their instruments. Their songs may be accompanied by the beating of cow-hide drums, blowing of reed-pipe whistles, animal horns, beating of sticks and hand-clapping. The most important instrument the AmaXhosa use is the human voice. They are experts in humming, gruff singing and whistling. The songs of the AmaXhosa encourage togetherness. When one composes a song, one does not express one’s own feelings, but also the feelings of the community. The AmaXhosa songs are about participation so group singing and dancing is encouraged. Everyone participates either by singing, dancing or clapping. x Respect is the central core of the AmaXhosa songs. That is why the songs are composed according to age groups and sex. Instruments are also used according to ages and sex. Written texts are also a tool to educate the reader. The writers have decided to include songs in their writings to act as a form of entertainment and education. Although some songs lack the hallmarks of a traditional song, they communicate the idea or relay the message the writer wants to convey to the reader. Terms: Mock enconuim, the grotesque and the principle of beautiful deformity, anaphoric construction, diction and connotation, authorial comments, the mask-persona form, usurping of authority and reduction of traditional status.
- Full Text:
- Date Issued: 2009
Sibling partnerships in South African small and medium-sized family businesses
- Authors: Farrington, Shelley Maeva
- Date: 2009
- Subjects: Family-owned business enterprises -- South Africa -- Management , Family corporations -- South Africa -- Management , Families -- Economic aspects -- South Africa , Small business -- Management -- South Africa , Family-owned business enterprises -- Succession -- South Africa
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: vital:9289 , http://hdl.handle.net/10948/952 , Family-owned business enterprises -- South Africa -- Management , Family corporations -- South Africa -- Management , Families -- Economic aspects -- South Africa , Small business -- Management -- South Africa , Family-owned business enterprises -- Succession -- South Africa
- Description: Given the predicted increase in the number of family businesses owned and/or managed by siblings (Sibling Partnerships), as well as the lack of understanding and research attention given to such sibling teams, the purpose of this study was to contribute to the more effective functioning of such family businesses in South Africa by identifying the factors that impact on their success. With this purpose in mind, the primary objective was to identify, investigate and empirically test the possible influences of, and relationships between, various factors and the Perceived success of Sibling Partnerships. This study sets out to integrate prior findings and theories on team effectiveness and family relationships, to find support for these theories in the family business literature, and to incorporate these findings into a comprehensive model. The literature study revealed 5 main categories (context, composition, structure, processes, and people) of constructs influencing the Perceived success of sibling teams. Within these 5 main constructs, 13 underlying independent variables were identified and hypothesised to influence measures of effectiveness of sibling teams, namely the dependent variable Perceived success, and the 2 intermediate variables Financial performance and Family harmony. Of the 13 underlying independent variables, 6 were categorised as task-based and 7 as relational-based factors. In addition, hypotheses were formulated for possible relationships between the various task-based constructs (context, composition and structure) and the processes and people constructs. Each construct was clearly defined and then operationalised. Operationalisation was done by using reliable and valid items sourced from tested measuring instruments used in previous studies, as well as several self-generated items based on secondary sources. A structured questionnaire was made available to respondents identified by means of the convenience snowball sampling technique, and the data collected from 371 usable questionnaires was subjected to various statistical analyses. An exploratory factor analysis was conducted, and Cronbach-alpha coefficients were calculated to confirm the validity and reliability of the measuring instrument. The 6 task-based latent variables were confirmed by the exploratory factor analysis. However, all the other latent variables, as originally intended in the theoretical model, could not be confirmed. Instead, 3 dependent variables were identified, namely Financial performance, Growth performance and Satisfaction with work and family relationships, and 6 relational-based constructs, with some changes, did emerge. Structural Equation Modelling (SEM) was the main statistical procedure used to test the significance of the relationships hypothesised between the various independent and dependent variables. Because of sample size restrictions the conceptual model could not be subjected to SEM as a whole; consequently 10 submodels were identified and subjected to further analysis. The following independent variables were identified as influencing the dependent variables in this study: • Internal context • Complementary skills • Leadership • Shared dream • Fairness • Sibling relationship • Non-family members • No other family members (spouses and non-active siblings) In addition, the factors Complementary skills, Leadership, Past parent involvement, No present parent involvement, and No other family members, were identified as significantly influencing the relationship between the siblings involved in the Sibling Partnership. Furthermore, an Analysis of Variance (ANOVA), Multiple Linear Regression analysis and t-tests were undertaken to determine the influence of demographic variables on the dependent variables. How ownership is shared in a family business involving siblings, the shareholding between the siblings themselves, and the nature of leadership between the siblings, has been found to influence the iv dependent variables in the present study. In addition, a Sibling Partnership is likely to perform most effectively when it is composed of a relatively young sibling team that has a small age gap between the members, and business performance will improve as the siblings gain work experience together, and as the number of employees increase. This study has added to the empirical body of family business research by investigating a particularly limited segment of the literature, namely Sibling Partnerships in family businesses. By identifying and developing various models that outline the most significant factors that influence the success of such family business partnerships, this study offers recommendations and suggestions for managing family businesses involving siblings, in such a way as to enrich their family relationships and to improve the financial performance of their businesses.
- Full Text:
- Date Issued: 2009
- Authors: Farrington, Shelley Maeva
- Date: 2009
- Subjects: Family-owned business enterprises -- South Africa -- Management , Family corporations -- South Africa -- Management , Families -- Economic aspects -- South Africa , Small business -- Management -- South Africa , Family-owned business enterprises -- Succession -- South Africa
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: vital:9289 , http://hdl.handle.net/10948/952 , Family-owned business enterprises -- South Africa -- Management , Family corporations -- South Africa -- Management , Families -- Economic aspects -- South Africa , Small business -- Management -- South Africa , Family-owned business enterprises -- Succession -- South Africa
- Description: Given the predicted increase in the number of family businesses owned and/or managed by siblings (Sibling Partnerships), as well as the lack of understanding and research attention given to such sibling teams, the purpose of this study was to contribute to the more effective functioning of such family businesses in South Africa by identifying the factors that impact on their success. With this purpose in mind, the primary objective was to identify, investigate and empirically test the possible influences of, and relationships between, various factors and the Perceived success of Sibling Partnerships. This study sets out to integrate prior findings and theories on team effectiveness and family relationships, to find support for these theories in the family business literature, and to incorporate these findings into a comprehensive model. The literature study revealed 5 main categories (context, composition, structure, processes, and people) of constructs influencing the Perceived success of sibling teams. Within these 5 main constructs, 13 underlying independent variables were identified and hypothesised to influence measures of effectiveness of sibling teams, namely the dependent variable Perceived success, and the 2 intermediate variables Financial performance and Family harmony. Of the 13 underlying independent variables, 6 were categorised as task-based and 7 as relational-based factors. In addition, hypotheses were formulated for possible relationships between the various task-based constructs (context, composition and structure) and the processes and people constructs. Each construct was clearly defined and then operationalised. Operationalisation was done by using reliable and valid items sourced from tested measuring instruments used in previous studies, as well as several self-generated items based on secondary sources. A structured questionnaire was made available to respondents identified by means of the convenience snowball sampling technique, and the data collected from 371 usable questionnaires was subjected to various statistical analyses. An exploratory factor analysis was conducted, and Cronbach-alpha coefficients were calculated to confirm the validity and reliability of the measuring instrument. The 6 task-based latent variables were confirmed by the exploratory factor analysis. However, all the other latent variables, as originally intended in the theoretical model, could not be confirmed. Instead, 3 dependent variables were identified, namely Financial performance, Growth performance and Satisfaction with work and family relationships, and 6 relational-based constructs, with some changes, did emerge. Structural Equation Modelling (SEM) was the main statistical procedure used to test the significance of the relationships hypothesised between the various independent and dependent variables. Because of sample size restrictions the conceptual model could not be subjected to SEM as a whole; consequently 10 submodels were identified and subjected to further analysis. The following independent variables were identified as influencing the dependent variables in this study: • Internal context • Complementary skills • Leadership • Shared dream • Fairness • Sibling relationship • Non-family members • No other family members (spouses and non-active siblings) In addition, the factors Complementary skills, Leadership, Past parent involvement, No present parent involvement, and No other family members, were identified as significantly influencing the relationship between the siblings involved in the Sibling Partnership. Furthermore, an Analysis of Variance (ANOVA), Multiple Linear Regression analysis and t-tests were undertaken to determine the influence of demographic variables on the dependent variables. How ownership is shared in a family business involving siblings, the shareholding between the siblings themselves, and the nature of leadership between the siblings, has been found to influence the iv dependent variables in the present study. In addition, a Sibling Partnership is likely to perform most effectively when it is composed of a relatively young sibling team that has a small age gap between the members, and business performance will improve as the siblings gain work experience together, and as the number of employees increase. This study has added to the empirical body of family business research by investigating a particularly limited segment of the literature, namely Sibling Partnerships in family businesses. By identifying and developing various models that outline the most significant factors that influence the success of such family business partnerships, this study offers recommendations and suggestions for managing family businesses involving siblings, in such a way as to enrich their family relationships and to improve the financial performance of their businesses.
- Full Text:
- Date Issued: 2009
Application of Baylis-Hillman methodology in the construction of complex heterocyclic targets
- Ganto, Mlungiseleli MacDonald
- Authors: Ganto, Mlungiseleli MacDonald
- Date: 2009
- Subjects: Heterocyclic compounds -- Derivatives Heterocyclic chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4401 , http://hdl.handle.net/10962/d1006703
- Description: Baylis-Hillman reactions using various aromatic aldehydes, activated alkenes and catalysts have been used to: - access an extensive range of poly-heterocyclic products;explore chemoselectivity; and optimise reaction efficiency. Chromone-3-carbaldehydes and chromone-2-carbaldehydes, prepared via Vielsmeier-Haack and Kostanecki-Robinson methodology, respectively, have been used as Baylis-Hillman substrates with four different catalysts, viz., 1,4-diazabicyclo[2.2.2]octane (DABCO), 3-hydroxyquinuclidine (3-HQ), imidazole and N’,N’,N’,N’- tetramethylpropanediamine (TMPDA), and with methyl vinyl ketone (MVK), methyl acrylate, cyclic enones (2-cyclohexen-1-one, 2-cyclopenten-1-one and chromones) as activated alkenes. Reactions of the chromone- -carbaldehydes with MVK afforded dimeric Baylis-Hillman adducts when catalyzed by DABCO but when the same reactions were repeated using 3-HQ as catalyst, the dimeric products were accompanied by tricyclic Baylis-Hillman adducts. Use of excess MVK, however, led to mixtures of the normal Baylis-Hillman adducts and the tricyclic adducts – interestingly, with the apparent absence of the dimeric products. While reactions of chromone-3-carbaldehydes with methyl acrylate afforded the normal Baylis-Hillman adducts, the chromone-2- carbaldehydes produced, instead, rearrangement products, consistent with an earlier, single observation. Reactions of 2-nitrobenzaldehydes with cyclic enones using imidazole as catalyst afforded the normal Baylis-Hillman adducts, reductive cyclisation of the 2-cyclohexen-1- one and 2-cyclopenten-1-one adducts, using acetic acid and iron powder, afforded the corresponding quinoline erivatives. Treatment of cyclic enones with pyridine-2-carbaldehydes and quinoline-2-carbaldehydes using TMPDA as catalyst generally gave the expected Baylis-Hillman adducts. However, indolizine derivatives were isolated directly from Baylis-Hillman reactions involving pyridine-2-carbaldehydes and 2-cyclohexen-1-one. The remaining Baylis-Hillman adducts were cyclized to the corresponding indolizines by treatment with acetic anhydride both under reflux and under microwave-assisted conditions, the latter approach providing remarkably rapid and efficient access to the polycyclic products. Computer modelling studies have been conducted on selected polycyclic products at the Molecular Mechanics (MM), Quantum Mechanical (QM) and Density Functional (DFT) levels. The theoretical results have been used to calculate UV, IR and NMR absorption data, which have been compared, in turn, with the experimental spectroscopic data. Use has also been made of the estreNova NMR prediction programme and, generally, good agreement has been observed between the predicted and experimental spectroscopic data.
- Full Text:
- Date Issued: 2009
- Authors: Ganto, Mlungiseleli MacDonald
- Date: 2009
- Subjects: Heterocyclic compounds -- Derivatives Heterocyclic chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4401 , http://hdl.handle.net/10962/d1006703
- Description: Baylis-Hillman reactions using various aromatic aldehydes, activated alkenes and catalysts have been used to: - access an extensive range of poly-heterocyclic products;explore chemoselectivity; and optimise reaction efficiency. Chromone-3-carbaldehydes and chromone-2-carbaldehydes, prepared via Vielsmeier-Haack and Kostanecki-Robinson methodology, respectively, have been used as Baylis-Hillman substrates with four different catalysts, viz., 1,4-diazabicyclo[2.2.2]octane (DABCO), 3-hydroxyquinuclidine (3-HQ), imidazole and N’,N’,N’,N’- tetramethylpropanediamine (TMPDA), and with methyl vinyl ketone (MVK), methyl acrylate, cyclic enones (2-cyclohexen-1-one, 2-cyclopenten-1-one and chromones) as activated alkenes. Reactions of the chromone- -carbaldehydes with MVK afforded dimeric Baylis-Hillman adducts when catalyzed by DABCO but when the same reactions were repeated using 3-HQ as catalyst, the dimeric products were accompanied by tricyclic Baylis-Hillman adducts. Use of excess MVK, however, led to mixtures of the normal Baylis-Hillman adducts and the tricyclic adducts – interestingly, with the apparent absence of the dimeric products. While reactions of chromone-3-carbaldehydes with methyl acrylate afforded the normal Baylis-Hillman adducts, the chromone-2- carbaldehydes produced, instead, rearrangement products, consistent with an earlier, single observation. Reactions of 2-nitrobenzaldehydes with cyclic enones using imidazole as catalyst afforded the normal Baylis-Hillman adducts, reductive cyclisation of the 2-cyclohexen-1- one and 2-cyclopenten-1-one adducts, using acetic acid and iron powder, afforded the corresponding quinoline erivatives. Treatment of cyclic enones with pyridine-2-carbaldehydes and quinoline-2-carbaldehydes using TMPDA as catalyst generally gave the expected Baylis-Hillman adducts. However, indolizine derivatives were isolated directly from Baylis-Hillman reactions involving pyridine-2-carbaldehydes and 2-cyclohexen-1-one. The remaining Baylis-Hillman adducts were cyclized to the corresponding indolizines by treatment with acetic anhydride both under reflux and under microwave-assisted conditions, the latter approach providing remarkably rapid and efficient access to the polycyclic products. Computer modelling studies have been conducted on selected polycyclic products at the Molecular Mechanics (MM), Quantum Mechanical (QM) and Density Functional (DFT) levels. The theoretical results have been used to calculate UV, IR and NMR absorption data, which have been compared, in turn, with the experimental spectroscopic data. Use has also been made of the estreNova NMR prediction programme and, generally, good agreement has been observed between the predicted and experimental spectroscopic data.
- Full Text:
- Date Issued: 2009
Automating the conversion of natural language fiction to multi-modal 3D animated virtual environments
- Authors: Glass, Kevin Robert
- Date: 2009
- Subjects: Virtual computer systems , Virtual storage (Computer science) , Virtual reality , Computer animation , Fiction -- Computer programs , Narration (Rhetoric) -- Computer simulation , Animation (Cinematography) , Natural language processing (Computer Science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4632 , http://hdl.handle.net/10962/d1006518
- Description: Popular fiction books describe rich visual environments that contain characters, objects, and behaviour. This research develops automated processes for converting text sourced from fiction books into animated virtual environments and multi-modal films. This involves the analysis of unrestricted natural language fiction to identify appropriate visual descriptions, and the interpretation of the identified descriptions for constructing animated 3D virtual environments. The goal of the text analysis stage is the creation of annotated fiction text, which identifies visual descriptions in a structured manner. A hierarchical rule-based learning system is created that induces patterns from example annotations provided by a human, and uses these for the creation of additional annotations. Patterns are expressed as tree structures that abstract the input text on different levels according to structural (token, sentence) and syntactic (parts-of-speech, syntactic function) categories. Patterns are generalized using pair-wise merging, where dissimilar sub-trees are replaced with wild-cards. The result is a small set of generalized patterns that are able to create correct annotations. A set of generalized patterns represents a model of an annotator's mental process regarding a particular annotation category. Annotated text is interpreted automatically for constructing detailed scene descriptions. This includes identifying which scenes to visualize, and identifying the contents and behaviour in each scene. Entity behaviour in a 3D virtual environment is formulated using time-based constraints that are automatically derived from annotations. Constraints are expressed as non-linear symbolic functions that restrict the trajectories of a pair of entities over a continuous interval of time. Solutions to these constraints specify precise behaviour. We create an innovative quantified constraint optimizer for locating sound solutions, which uses interval arithmetic for treating time and space as contiguous quantities. This optimization method uses a technique of constraint relaxation and tightening that allows solution approximations to be located where constraint systems are inconsistent (an ability not previously explored in interval-based quantified constraint solving). 3D virtual environments are populated by automatically selecting geometric models or procedural geometry-creation methods from a library. 3D models are animated according to trajectories derived from constraint solutions. The final animated film is sequenced using a range of modalities including animated 3D graphics, textual subtitles, audio narrations, and foleys. Hierarchical rule-based learning is evaluated over a range of annotation categories. Models are induced for different categories of annotation without modifying the core learning algorithms, and these models are shown to be applicable to different types of books. Models are induced automatically with accuracies ranging between 51.4% and 90.4%, depending on the category. We show that models are refined if further examples are provided, and this supports a boot-strapping process for training the learning mechanism. The task of interpreting annotated fiction text and populating 3D virtual environments is successfully automated using our described techniques. Detailed scene descriptions are created accurately, where between 83% and 96% of the automatically generated descriptions require no manual modification (depending on the type of description). The interval-based quantified constraint optimizer fully automates the behaviour specification process. Sample animated multi-modal 3D films are created using extracts from fiction books that are unrestricted in terms of complexity or subject matter (unlike existing text-to-graphics systems). These examples demonstrate that: behaviour is visualized that corresponds to the descriptions in the original text; appropriate geometry is selected (or created) for visualizing entities in each scene; sequences of scenes are created for a film-like presentation of the story; and that multiple modalities are combined to create a coherent multi-modal representation of the fiction text. This research demonstrates that visual descriptions in fiction text can be automatically identified, and that these descriptions can be converted into corresponding animated virtual environments. Unlike existing text-to-graphics systems, we describe techniques that function over unrestricted natural language text and perform the conversion process without the need for manually constructed repositories of world knowledge. This enables the rapid production of animated 3D virtual environments, allowing the human designer to focus on creative aspects.
- Full Text:
- Date Issued: 2009
- Authors: Glass, Kevin Robert
- Date: 2009
- Subjects: Virtual computer systems , Virtual storage (Computer science) , Virtual reality , Computer animation , Fiction -- Computer programs , Narration (Rhetoric) -- Computer simulation , Animation (Cinematography) , Natural language processing (Computer Science)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4632 , http://hdl.handle.net/10962/d1006518
- Description: Popular fiction books describe rich visual environments that contain characters, objects, and behaviour. This research develops automated processes for converting text sourced from fiction books into animated virtual environments and multi-modal films. This involves the analysis of unrestricted natural language fiction to identify appropriate visual descriptions, and the interpretation of the identified descriptions for constructing animated 3D virtual environments. The goal of the text analysis stage is the creation of annotated fiction text, which identifies visual descriptions in a structured manner. A hierarchical rule-based learning system is created that induces patterns from example annotations provided by a human, and uses these for the creation of additional annotations. Patterns are expressed as tree structures that abstract the input text on different levels according to structural (token, sentence) and syntactic (parts-of-speech, syntactic function) categories. Patterns are generalized using pair-wise merging, where dissimilar sub-trees are replaced with wild-cards. The result is a small set of generalized patterns that are able to create correct annotations. A set of generalized patterns represents a model of an annotator's mental process regarding a particular annotation category. Annotated text is interpreted automatically for constructing detailed scene descriptions. This includes identifying which scenes to visualize, and identifying the contents and behaviour in each scene. Entity behaviour in a 3D virtual environment is formulated using time-based constraints that are automatically derived from annotations. Constraints are expressed as non-linear symbolic functions that restrict the trajectories of a pair of entities over a continuous interval of time. Solutions to these constraints specify precise behaviour. We create an innovative quantified constraint optimizer for locating sound solutions, which uses interval arithmetic for treating time and space as contiguous quantities. This optimization method uses a technique of constraint relaxation and tightening that allows solution approximations to be located where constraint systems are inconsistent (an ability not previously explored in interval-based quantified constraint solving). 3D virtual environments are populated by automatically selecting geometric models or procedural geometry-creation methods from a library. 3D models are animated according to trajectories derived from constraint solutions. The final animated film is sequenced using a range of modalities including animated 3D graphics, textual subtitles, audio narrations, and foleys. Hierarchical rule-based learning is evaluated over a range of annotation categories. Models are induced for different categories of annotation without modifying the core learning algorithms, and these models are shown to be applicable to different types of books. Models are induced automatically with accuracies ranging between 51.4% and 90.4%, depending on the category. We show that models are refined if further examples are provided, and this supports a boot-strapping process for training the learning mechanism. The task of interpreting annotated fiction text and populating 3D virtual environments is successfully automated using our described techniques. Detailed scene descriptions are created accurately, where between 83% and 96% of the automatically generated descriptions require no manual modification (depending on the type of description). The interval-based quantified constraint optimizer fully automates the behaviour specification process. Sample animated multi-modal 3D films are created using extracts from fiction books that are unrestricted in terms of complexity or subject matter (unlike existing text-to-graphics systems). These examples demonstrate that: behaviour is visualized that corresponds to the descriptions in the original text; appropriate geometry is selected (or created) for visualizing entities in each scene; sequences of scenes are created for a film-like presentation of the story; and that multiple modalities are combined to create a coherent multi-modal representation of the fiction text. This research demonstrates that visual descriptions in fiction text can be automatically identified, and that these descriptions can be converted into corresponding animated virtual environments. Unlike existing text-to-graphics systems, we describe techniques that function over unrestricted natural language text and perform the conversion process without the need for manually constructed repositories of world knowledge. This enables the rapid production of animated 3D virtual environments, allowing the human designer to focus on creative aspects.
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- Date Issued: 2009