Peer group supervision as an adjunct to individual supervision: an investigation of models of learning
- Akhurst, Jacqueline Elizabeth
- Authors: Akhurst, Jacqueline Elizabeth
- Date: 2000
- Subjects: Peer-group tutoring of students Psychotherapy -- Study and teaching -- Supervision Psychology -- Supervision of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2922 , http://hdl.handle.net/10962/d1002431
- Description: Supervision of practice makes an important contribution to the development of psychotherapeutic skills in the training of psychologists (Bernard and Goodyear, 1998). Much research has, until recently, focussed on dyadic, hierarchical models of supervision, even though other forms of supervision have been developed. Peer group supervision has had little attention in the literature, although it is a common form of supervision utilised by psychologists in practice (Lewis, Greenburg and Hatch, 1988). A review of the literature considers the purposes of supervision; elements of dyadic supervision; various forms of group, peer and peer group supervision; and the leaming process in supervision. The development and implementation of a peer supervision group (pSG) of intern psychologists within the training setting of a University is described in this study. The PSG model was developed from the model proposed by Wilbur, Roberts-Wilbur, Morris, Betz and Hart (1991). Transcripts from nine audio-taped PSG sessions were analysed, and a comparison with four audio-taped dyadic supervision sessions was then undertaken. Grounded Theory methodology was employed in the design of the study and analysis of the data. The form and content of the two models of supervision were examined, with particular attention to the perspective of the trainees' learning experiences. The relative merits of both forms of supervision were assessed, and this analysis clearly demonstrates that peer group supervision has the potential to complement dyadic supervision by contributing differing learning experiences. A model of key influences upon, and effects of, participation in the two forms of supervision has been developed. Suggestions are made of ways in which dyadic supervision may be optimised, and recommendations for further development of the PSG emerge. The results were then considered from a neo-Vygotskian perspective. This enabled the findings to be linked to a comprehensive theory of learning, pointing to the key role of speech in thinking, and the contributions of the various forms of dialogue to deepened understandings. The discussion includes: consideration of techniques which enable trainees to obtain assistance from both more experienced practitioners as well as from their peers; an exploration of aspects of subjectivity and intersubjectivity; and contextual influences which have bearing on the study. This study identifies the need for further consideration of the supervision process in South Africa, and makes recommendations for the training of supervisors. The neo-Vygotskian model offers great promise both as a framework for understanding the leaming process in. supervision, and for developing guidelines for enhancing supervisory practice.
- Full Text:
- Date Issued: 2000
- Authors: Akhurst, Jacqueline Elizabeth
- Date: 2000
- Subjects: Peer-group tutoring of students Psychotherapy -- Study and teaching -- Supervision Psychology -- Supervision of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2922 , http://hdl.handle.net/10962/d1002431
- Description: Supervision of practice makes an important contribution to the development of psychotherapeutic skills in the training of psychologists (Bernard and Goodyear, 1998). Much research has, until recently, focussed on dyadic, hierarchical models of supervision, even though other forms of supervision have been developed. Peer group supervision has had little attention in the literature, although it is a common form of supervision utilised by psychologists in practice (Lewis, Greenburg and Hatch, 1988). A review of the literature considers the purposes of supervision; elements of dyadic supervision; various forms of group, peer and peer group supervision; and the leaming process in supervision. The development and implementation of a peer supervision group (pSG) of intern psychologists within the training setting of a University is described in this study. The PSG model was developed from the model proposed by Wilbur, Roberts-Wilbur, Morris, Betz and Hart (1991). Transcripts from nine audio-taped PSG sessions were analysed, and a comparison with four audio-taped dyadic supervision sessions was then undertaken. Grounded Theory methodology was employed in the design of the study and analysis of the data. The form and content of the two models of supervision were examined, with particular attention to the perspective of the trainees' learning experiences. The relative merits of both forms of supervision were assessed, and this analysis clearly demonstrates that peer group supervision has the potential to complement dyadic supervision by contributing differing learning experiences. A model of key influences upon, and effects of, participation in the two forms of supervision has been developed. Suggestions are made of ways in which dyadic supervision may be optimised, and recommendations for further development of the PSG emerge. The results were then considered from a neo-Vygotskian perspective. This enabled the findings to be linked to a comprehensive theory of learning, pointing to the key role of speech in thinking, and the contributions of the various forms of dialogue to deepened understandings. The discussion includes: consideration of techniques which enable trainees to obtain assistance from both more experienced practitioners as well as from their peers; an exploration of aspects of subjectivity and intersubjectivity; and contextual influences which have bearing on the study. This study identifies the need for further consideration of the supervision process in South Africa, and makes recommendations for the training of supervisors. The neo-Vygotskian model offers great promise both as a framework for understanding the leaming process in. supervision, and for developing guidelines for enhancing supervisory practice.
- Full Text:
- Date Issued: 2000
Surface properties and electrocatalytic applications of metallophthalocyanines confined on electrode surfaces
- Authors: Akinbulu, Isaac Adebayo
- Date: 2011
- Subjects: Phthalocyanines Electrochemistry Electrocatalysis Pesticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4365 , http://hdl.handle.net/10962/d1005030
- Description: New cobalt (13, 16 19 and 22), manganese (14, 17, 20 and 23) and iron (15, 18, 21 and 24)phthalocyanine complexes were synthesized and characterized. The UV-Vis spectral properties of the complexes were typical of the nature of central metal and position of substituent on the Pc ligand. Their electrochemical behaviors were signatures of the central metals, with varying influences of the nature and position of substituents. Nanocomposite of complex 18 and single walled carbon nanotubes (SWCNTs) (SWCNT-18)was fabricated. Formation of this nano-composite was confirmed by infrared (IR)spectroscopy, X-ray diffraction (XRD) spectroscopy and transmission electron microscopy (TEM). Self-assembled monolayers (SAMs) of SWCNT-18, complexes 13-15, and 20 were electropolymerized on glassy carbon electrodes (GCE). Complex 14 was also electrodeposited on GCE. Surface properties of the SAMs were consistent with the molecular feature of the substituent and the nature of central metal in the adsorbed species, while those of the MnPc modified GCEs were dependent on point of substitution and number of substituent. The SAM-modified gold electrodes were used for the electrocatalytic oxidation of the carbamate insecticide, carbofuran. Amplification of the current signal of the insecticide, at more energetically feasible oxidation potentials, on the SAM-modified gold electrodes, relative to bare gold electrode,justified electrocatalysis. There was enhanced sensitivity (attributed to the presence of SWCNT) of the SWCNT-18-SAM-modified gold electrode towards carbofuran, relative to the signals observed on the other SAMs. Current response of the insecticide,bendiocarb, was also intensified, at more favorable oxidation potentials, on the MnPc (14 and 17) modified GCEs, relative to the response on bare GCE, substantiating electrocatalysis. Also, catalysis of the oxidation of the herbicide, bentazon, was observed on polymeric film of complex 20. The current response of the herbicide on this film was better than that observed on bare GCE. Electrocatalysis of the analytes, on the respective modified electrodes, occurred via closely related mechanisms.
- Full Text:
- Date Issued: 2011
- Authors: Akinbulu, Isaac Adebayo
- Date: 2011
- Subjects: Phthalocyanines Electrochemistry Electrocatalysis Pesticides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4365 , http://hdl.handle.net/10962/d1005030
- Description: New cobalt (13, 16 19 and 22), manganese (14, 17, 20 and 23) and iron (15, 18, 21 and 24)phthalocyanine complexes were synthesized and characterized. The UV-Vis spectral properties of the complexes were typical of the nature of central metal and position of substituent on the Pc ligand. Their electrochemical behaviors were signatures of the central metals, with varying influences of the nature and position of substituents. Nanocomposite of complex 18 and single walled carbon nanotubes (SWCNTs) (SWCNT-18)was fabricated. Formation of this nano-composite was confirmed by infrared (IR)spectroscopy, X-ray diffraction (XRD) spectroscopy and transmission electron microscopy (TEM). Self-assembled monolayers (SAMs) of SWCNT-18, complexes 13-15, and 20 were electropolymerized on glassy carbon electrodes (GCE). Complex 14 was also electrodeposited on GCE. Surface properties of the SAMs were consistent with the molecular feature of the substituent and the nature of central metal in the adsorbed species, while those of the MnPc modified GCEs were dependent on point of substitution and number of substituent. The SAM-modified gold electrodes were used for the electrocatalytic oxidation of the carbamate insecticide, carbofuran. Amplification of the current signal of the insecticide, at more energetically feasible oxidation potentials, on the SAM-modified gold electrodes, relative to bare gold electrode,justified electrocatalysis. There was enhanced sensitivity (attributed to the presence of SWCNT) of the SWCNT-18-SAM-modified gold electrode towards carbofuran, relative to the signals observed on the other SAMs. Current response of the insecticide,bendiocarb, was also intensified, at more favorable oxidation potentials, on the MnPc (14 and 17) modified GCEs, relative to the response on bare GCE, substantiating electrocatalysis. Also, catalysis of the oxidation of the herbicide, bentazon, was observed on polymeric film of complex 20. The current response of the herbicide on this film was better than that observed on bare GCE. Electrocatalysis of the analytes, on the respective modified electrodes, occurred via closely related mechanisms.
- Full Text:
- Date Issued: 2011
Characterisation of dissimilar friction stir welds between 5754 Aluminium alloy and C11000 copper
- Authors: Akinlabi, Esther Titilayo
- Date: 2010
- Subjects: Friction stir welding , Aluminum alloys , Copper alloys
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9629 , http://hdl.handle.net/10948/1536 , Friction stir welding , Aluminum alloys , Copper alloys
- Description: Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in 1991, for joining ferrous and non-ferrous materials1. The FSW of Aluminium and its alloys has been commercialised; and recent interest is focused on joining dissimilar materials. However, in order to commercialise the process, research studies are required to characterise and establish process windows. This research work through material characterisation of the welded joints establishes a process window for the Friction Stir welding of 5754 Aluminium Alloy and C11000 Copper. Furthermore, preliminary studies83,85 on the FSW of aluminium and copper have revealed the presence of intermetallic compounds which are detrimental to the weld qualities. This research work is also aimed at establishing process parameters that will result in limited or no intermetallic formation in the weld. The joint integrity of the resulting welds will also be correlated with the input process parameters. Based on the preliminary investigations conducted, a final weld matrix consisting of twenty seven welds was produced by varying the rotational speed between 600 and 1200 rpm, and the feed rate between 50 and 300 mm/min using three different shoulder diameter tools – 15, 18 and 25 mm to compare the heat input into the welds and to achieve the best results. The welds were characterised through microstructural evaluation, tensile testing, microhardness profiling, X-Ray Diffraction analysis, electrical resistivity and statistical analysis – in order to establish the interrelationship between the process parameters and the weld qualities. viii Microstructural evaluation of the weld samples revealed that the interfacial regions are characterised by mixture layers of aluminium and copper; while 33 percent of the tensile samples are within the acceptable range (> 75 percent joint efficiency). High Vickers microhardness values were measured at the joint interfaces, which corresponded with the intermetallic compounds. The Energy Dispersive Spectroscopy analysis revealed the presence of thin layers of intermetallics in nanoscale at the interfacial regions. The diffractograms of the X-Ray Diffraction analysis showed small peaks for intermetallics in some of the welds. Low electrical resistivities were measured at the joint interfaces. The statistical analysis showed that the downward vertical force, (Fz) can significantly influence the resulting weld qualities. An overall summary of the analysis of the weld qualities - with respect to the shoulder diameter tools employed showed that the 18 mm shoulder diameter tool is most appropriate among the three shoulder diameters considered, and a process window of medium spindle speed of 950 rpm and low-to-medium feed rate between 50 and 150 mm/min is established for FSW of Aluminium and Copper. Welds produced at 1200 rpm and 300 mm/min with low heat input did not have intermetallics formed at the joint interface.
- Full Text:
- Date Issued: 2010
- Authors: Akinlabi, Esther Titilayo
- Date: 2010
- Subjects: Friction stir welding , Aluminum alloys , Copper alloys
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9629 , http://hdl.handle.net/10948/1536 , Friction stir welding , Aluminum alloys , Copper alloys
- Description: Friction Stir Welding (FSW) is a solid state welding process invented and patented by The Welding Institute (TWI) in 1991, for joining ferrous and non-ferrous materials1. The FSW of Aluminium and its alloys has been commercialised; and recent interest is focused on joining dissimilar materials. However, in order to commercialise the process, research studies are required to characterise and establish process windows. This research work through material characterisation of the welded joints establishes a process window for the Friction Stir welding of 5754 Aluminium Alloy and C11000 Copper. Furthermore, preliminary studies83,85 on the FSW of aluminium and copper have revealed the presence of intermetallic compounds which are detrimental to the weld qualities. This research work is also aimed at establishing process parameters that will result in limited or no intermetallic formation in the weld. The joint integrity of the resulting welds will also be correlated with the input process parameters. Based on the preliminary investigations conducted, a final weld matrix consisting of twenty seven welds was produced by varying the rotational speed between 600 and 1200 rpm, and the feed rate between 50 and 300 mm/min using three different shoulder diameter tools – 15, 18 and 25 mm to compare the heat input into the welds and to achieve the best results. The welds were characterised through microstructural evaluation, tensile testing, microhardness profiling, X-Ray Diffraction analysis, electrical resistivity and statistical analysis – in order to establish the interrelationship between the process parameters and the weld qualities. viii Microstructural evaluation of the weld samples revealed that the interfacial regions are characterised by mixture layers of aluminium and copper; while 33 percent of the tensile samples are within the acceptable range (> 75 percent joint efficiency). High Vickers microhardness values were measured at the joint interfaces, which corresponded with the intermetallic compounds. The Energy Dispersive Spectroscopy analysis revealed the presence of thin layers of intermetallics in nanoscale at the interfacial regions. The diffractograms of the X-Ray Diffraction analysis showed small peaks for intermetallics in some of the welds. Low electrical resistivities were measured at the joint interfaces. The statistical analysis showed that the downward vertical force, (Fz) can significantly influence the resulting weld qualities. An overall summary of the analysis of the weld qualities - with respect to the shoulder diameter tools employed showed that the 18 mm shoulder diameter tool is most appropriate among the three shoulder diameters considered, and a process window of medium spindle speed of 950 rpm and low-to-medium feed rate between 50 and 150 mm/min is established for FSW of Aluminium and Copper. Welds produced at 1200 rpm and 300 mm/min with low heat input did not have intermetallics formed at the joint interface.
- Full Text:
- Date Issued: 2010
Antidiabetic and toxicological properties of Dianthus thunbergii (Caryophyllaceae) roots and Hypoxis argentea (Hypoxidaceae) corms
- Authors: Akinrinde, Akinleye Stephen
- Date: 2017
- Subjects: Medicinal plants--South Africa--Eastern Cape Traditional medicine--South Africa--Eastern Cape Diabetics--Alternative treatment--South Africa
- Language: English
- Type: Thesis , Doctoral , Biochemistry
- Identifier: http://hdl.handle.net/10353/16036 , vital:40606
- Description: Diabetes mellitus is a chronic metabolic disorder primarily characterized by elevated blood glucose levels. Its rapidly increasing prevalence as a major non-communicable disease is now a growing concern for both developed and developing countries. The development of safe, cost-effective and pharmacologically-effective medications continues to a major challenge of antidiabetic management. Since most conventional antidiabetic drugs are costly and present with numerous adverse effects, alternatives are increasingly being sought from natural sources, most notably medicinal plants, as viable approaches to tackling the scourge of this disease. In the Eastern Cape Province of South Africa, the roots of Dianthus thunbergii and corms of Hypoxis argentea are frequently used traditionally for the treatment of diabetes mellitus, although no scientific evidence exists to validate their effectiveness for diabetes management. The studies conducted in the resent research were, therefore, aimed at investigating the antidiabetic and toxicological properties of these plants, in an attempt to providing data towards validating their use in traditional management of diabetes mellitus. Aqueous and ethanol extracts of the underground parts of D. thunbergii and H. argentea were initially subjected to analysis of their phytochemical composition, relative to standard compounds, and the nature of their in-vitro antioxidant activities using standard spectrophotometric methods. The potentials of these extracts for cytotoxicity and/or cell proliferation were evaluated using MTT assay in HepG2 cells and Crystal violet assay in INS-1 cells. These activities were further examined in INS-1 cells using live cell fluorescence imaging techniques. To evaluate the antidiabetic properties of the extracts, they were screened for their inhibitory effects on the activities of different enzymes including α-amylase, α-glucosidase, porcine pancreatic lipase, Dipeptidyl peptidase IV (DPP-IV), collagenase and the drug metabolizing enzyme, CYP3A4, while also assessing their effects on protein glycation using in- vitro visible and fluorescence spectrophotometric approaches. Cell culture procedures were carried out to evaluate the effects of the extracts on glucose utilization in HepG2 cells and L6 myotubes; nitric oxide production in RAW 264.7 macrophages; glucose metabolism in INS-1 cells, as well as triglyceride accumulation in 3T3-L1 pre-adipocytes. Furthermore, identification of compounds present in the aqueous and ethanol extracts was carried out by Liquid chromatography- Mass spectrometry (LC-MS), while volatile oils extracted from fresh and dried parts of the two plants by hydrodistillation were also analyzed by Gas chromatography-Mass spectrometry (GC-MS). The ethanol extracts of both D. thunbergii and H. argentea contained higher amounts of total phenols, flavonoids, tannins, proanthocyanidins and alkaloids, when compared with the aqueous extracts. This finding was in direct correlation with the antioxidant activities of the extracts, with the ethanol extracts of both plants demonstrating stronger scavenging activities against hydrogen peroxide, nitric oxide, ABTS and DPPH radicals, while also exhibiting higher ferric reducing antioxidant potentials, when compared with the aqueous extracts, and in some cases, the standard antioxidants, Vitamin C, butylated hydroxytoluene and rutin. The aqueous extracts of D. thunbergii exhibited the highest toxicity in HepG2 cells with IC50 < 50 μg/ml, while also producing a concentration-dependent reduction in the viability of INS-1 cells up to 41.81percent at 50 μg/ml. Both extracts of H. argentea, however, did not produce any significant toxicity in these cells. Fluorescence imaging of live INS-1 cells using Hoechst and propidium iodide staining revealed stimulation of cell proliferation by H. argentea, while the cytotoxicity of D. thunbergii was further confirmed. H. argentea caused stimulation of glucose uptake in HepG2 cells up to 119.58 percent at 100 μg/ml and as much as 116.96 percent in L6 myotubes at 50 μg/ml, without showing toxicity to these cells. D. thunbergii produced 18.39 percent increase in L6 glucose uptake above untreated control; although its effect on HepG2 glucose uptake was irrelevant as significant toxicity was produced in these cells. H. argentea produced a concentration-dependent reduction in nitric oxide production in RAW macrophages, although not as effectively as the positive control, aminoguanidine. Again, the toxicity of D. thunbergii to this cell line precludes the relevance of nitric oxide inhibition as an antidiabetic mechanism for this plant. D. thunbergii produced a concentration-dependent increase in 3T3-L1 triglyceride accumulation, as measured by Oil red O staining, compared to untreated cells, while H. argentea exerted no significant alterations in pre- adipocyte differentiation. Generally, the two plants produced weak inhibition of the activities of the various enzymes measured, suggesting that this mechanism may not play a major role in the activities of these plants as possible antidiabetic agents. GC-MS analysis revealed major differences in the volatile oil composition between fresh and dried plant parts for both plants. Most notably, total terpenoid content of D. thunbergii oils reduced significantly from 77.17 percent in the fresh root oil to 47.58 percent in the dried root oil. Total terpenoid content was much lower in H. argentea oils, but similarly reduced from 10.58 percent in the fresh corm oil to 4.00 percent in the dried corm oil. LC-MS analysis enabled the tentative identification of compounds including phenolic glycosides, flavonoids, alkaloids, terpenoids saponins and sapogenins, many of which have been reported in literature to exert bioactivities relevant to the ones elucidated in the present study. Overall, H. argentea exhibited antidiabetic properties that may be mediated by its stimulation of glucose uptake in HepG2 and L6 cells; stimulation of proliferation in INS-1 cells; lack of stimulation of 3T3-L1 triglyceride accumulation and a tendency to reduce nitric oxide production in RAW macrophages. These activities suggest that H. argentea has promise for further investigations as an antidiabetic agent. On the contrary, D. thunbergii exhibited significant toxicity to HepG2 cells, INS-1 cells and RAW macrophages. Its cytotoxicity at the concentrations investigated in the present studies raises significant concerns about any potential antidiabetic applications for this plant.
- Full Text:
- Date Issued: 2017
- Authors: Akinrinde, Akinleye Stephen
- Date: 2017
- Subjects: Medicinal plants--South Africa--Eastern Cape Traditional medicine--South Africa--Eastern Cape Diabetics--Alternative treatment--South Africa
- Language: English
- Type: Thesis , Doctoral , Biochemistry
- Identifier: http://hdl.handle.net/10353/16036 , vital:40606
- Description: Diabetes mellitus is a chronic metabolic disorder primarily characterized by elevated blood glucose levels. Its rapidly increasing prevalence as a major non-communicable disease is now a growing concern for both developed and developing countries. The development of safe, cost-effective and pharmacologically-effective medications continues to a major challenge of antidiabetic management. Since most conventional antidiabetic drugs are costly and present with numerous adverse effects, alternatives are increasingly being sought from natural sources, most notably medicinal plants, as viable approaches to tackling the scourge of this disease. In the Eastern Cape Province of South Africa, the roots of Dianthus thunbergii and corms of Hypoxis argentea are frequently used traditionally for the treatment of diabetes mellitus, although no scientific evidence exists to validate their effectiveness for diabetes management. The studies conducted in the resent research were, therefore, aimed at investigating the antidiabetic and toxicological properties of these plants, in an attempt to providing data towards validating their use in traditional management of diabetes mellitus. Aqueous and ethanol extracts of the underground parts of D. thunbergii and H. argentea were initially subjected to analysis of their phytochemical composition, relative to standard compounds, and the nature of their in-vitro antioxidant activities using standard spectrophotometric methods. The potentials of these extracts for cytotoxicity and/or cell proliferation were evaluated using MTT assay in HepG2 cells and Crystal violet assay in INS-1 cells. These activities were further examined in INS-1 cells using live cell fluorescence imaging techniques. To evaluate the antidiabetic properties of the extracts, they were screened for their inhibitory effects on the activities of different enzymes including α-amylase, α-glucosidase, porcine pancreatic lipase, Dipeptidyl peptidase IV (DPP-IV), collagenase and the drug metabolizing enzyme, CYP3A4, while also assessing their effects on protein glycation using in- vitro visible and fluorescence spectrophotometric approaches. Cell culture procedures were carried out to evaluate the effects of the extracts on glucose utilization in HepG2 cells and L6 myotubes; nitric oxide production in RAW 264.7 macrophages; glucose metabolism in INS-1 cells, as well as triglyceride accumulation in 3T3-L1 pre-adipocytes. Furthermore, identification of compounds present in the aqueous and ethanol extracts was carried out by Liquid chromatography- Mass spectrometry (LC-MS), while volatile oils extracted from fresh and dried parts of the two plants by hydrodistillation were also analyzed by Gas chromatography-Mass spectrometry (GC-MS). The ethanol extracts of both D. thunbergii and H. argentea contained higher amounts of total phenols, flavonoids, tannins, proanthocyanidins and alkaloids, when compared with the aqueous extracts. This finding was in direct correlation with the antioxidant activities of the extracts, with the ethanol extracts of both plants demonstrating stronger scavenging activities against hydrogen peroxide, nitric oxide, ABTS and DPPH radicals, while also exhibiting higher ferric reducing antioxidant potentials, when compared with the aqueous extracts, and in some cases, the standard antioxidants, Vitamin C, butylated hydroxytoluene and rutin. The aqueous extracts of D. thunbergii exhibited the highest toxicity in HepG2 cells with IC50 < 50 μg/ml, while also producing a concentration-dependent reduction in the viability of INS-1 cells up to 41.81percent at 50 μg/ml. Both extracts of H. argentea, however, did not produce any significant toxicity in these cells. Fluorescence imaging of live INS-1 cells using Hoechst and propidium iodide staining revealed stimulation of cell proliferation by H. argentea, while the cytotoxicity of D. thunbergii was further confirmed. H. argentea caused stimulation of glucose uptake in HepG2 cells up to 119.58 percent at 100 μg/ml and as much as 116.96 percent in L6 myotubes at 50 μg/ml, without showing toxicity to these cells. D. thunbergii produced 18.39 percent increase in L6 glucose uptake above untreated control; although its effect on HepG2 glucose uptake was irrelevant as significant toxicity was produced in these cells. H. argentea produced a concentration-dependent reduction in nitric oxide production in RAW macrophages, although not as effectively as the positive control, aminoguanidine. Again, the toxicity of D. thunbergii to this cell line precludes the relevance of nitric oxide inhibition as an antidiabetic mechanism for this plant. D. thunbergii produced a concentration-dependent increase in 3T3-L1 triglyceride accumulation, as measured by Oil red O staining, compared to untreated cells, while H. argentea exerted no significant alterations in pre- adipocyte differentiation. Generally, the two plants produced weak inhibition of the activities of the various enzymes measured, suggesting that this mechanism may not play a major role in the activities of these plants as possible antidiabetic agents. GC-MS analysis revealed major differences in the volatile oil composition between fresh and dried plant parts for both plants. Most notably, total terpenoid content of D. thunbergii oils reduced significantly from 77.17 percent in the fresh root oil to 47.58 percent in the dried root oil. Total terpenoid content was much lower in H. argentea oils, but similarly reduced from 10.58 percent in the fresh corm oil to 4.00 percent in the dried corm oil. LC-MS analysis enabled the tentative identification of compounds including phenolic glycosides, flavonoids, alkaloids, terpenoids saponins and sapogenins, many of which have been reported in literature to exert bioactivities relevant to the ones elucidated in the present study. Overall, H. argentea exhibited antidiabetic properties that may be mediated by its stimulation of glucose uptake in HepG2 and L6 cells; stimulation of proliferation in INS-1 cells; lack of stimulation of 3T3-L1 triglyceride accumulation and a tendency to reduce nitric oxide production in RAW macrophages. These activities suggest that H. argentea has promise for further investigations as an antidiabetic agent. On the contrary, D. thunbergii exhibited significant toxicity to HepG2 cells, INS-1 cells and RAW macrophages. Its cytotoxicity at the concentrations investigated in the present studies raises significant concerns about any potential antidiabetic applications for this plant.
- Full Text:
- Date Issued: 2017
Quantification of the cross-sectoral impacts of waterweeds and their control in Ghana
- Authors: Akpabey, Felix Jerry
- Date: 2012
- Subjects: Water hyacinth -- Control -- Environmental aspects -- Ghana Alien plants -- Research -- Ghana Introduced organisms Economic development -- Social aspects -- Research -- Ghana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5748 , http://hdl.handle.net/10962/d1005435
- Description: The Akosombo Dam on the Volta River in Ghana was built in 1963 to provide cheap energy to fuel industry and to accelerate the economic growth of the country. It provides hydroelectric power, enhanced fishing and water transportation upstream, and improved opportunities for irrigated farming, especially in the lower reaches, and their attendant economic multiplier effects. A few years after the construction of this major dam, a rapid expansion of industrialization took place in Ghana. This brought about an exponential increase in demand for more electrical power. This led to the construction of a smaller dam at Akuse, downstream of the Akosomho Dam in 1981 and the formation of a headpond at Kpong. The impoundment of the river at the two sites (Akosombo and Kpong) caused an alteration in the existing ecological and biophysical processes in the river basin, including a slowing of the flow of the river, upstream and downstream. Changes in the natural processes, such as a reduction in the flow of the river and an increase in nutrient status of the water, resulted in an invasion of aquatic weeds, increasing the density of aquatic snails (intermediate hosts of schistosomiasis), silting and closure of the estuary, as well as other more subtle effects. The invasion of the river's main course and the dams by aquatic plants led to a corresponding reduction of navigable water both upstream and downstream. The aim of this thesis was to quantify the impact and control of waterweeds, especially water hyacinth, Eichhornia crassipes (Mart) Solms-Laubach (Pontederiaceae), in Ghana. A floral survey on the Kpong Headpond recorded 49 emergent, 12 free floating and I submerged aquatic plant species, many of which were indigenous, but the exotic or introduced water hyacinth was recorded at most of the sampling sites, and was the most abundant and had the biggest impact on the utilization of the water resource. Mats of water hyacinth served as substrates for other, indigenous species to grow out into the main channel of the headpond, including the intake point of the Kpong head works of the Ghana Water Company Limited (GWCL) and landing sites for boats. These mats resulted in a reduction of the fish (fin and shell) harvest, reducing the annual production to far below demand. Water hyacinth was also shown to have severe health implications. A survey of the Ministry of Health records showed that the prevalence of both urinary and intestinal schistosomiasis had risen significantly over time as the abundance of waterweeds, most notably water hyacinth, increased, and ranged between 70% and 75% but up to 100% in some lakeside communities. Based on the work done by an NGO on board the medical boat ("Onipa Nua "), losses in terms of money due to the effect on health of the aquatic weed infestations on the Volta River in 2006 amounted to US$ 620,000. Economic losses due to invasive alien aquatic weeds were also calculated on the Oti River Arm of Lake Volta. It was estimated that about US$2.3 million per annum would be lost to the Volta Lake Transport Company and individual boat transport operators if this section of the river were 100% covered by aquatic weeds (water hyacinth and Salvinia molesta D.S. Mitchell (Salviniaceae)). It was also estimated that US$327,038 was spent annually in monitoring and managing the weeds in the Oti River. Control interventions for aquatic weeds have been implemented in river systems in Ghana. The biological control agents Neochetina bruchi Hustache (Coleoptera, Curculionidae) and Neochetina eichhorniae Warner (Coleoptera, Curculionidae) have been used on water hyacinth infestations in the Oti River Arm of Lake Volta, the Tano River and the Lagoon complex in the south-western part of the country. Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) has been used to control salvinia, and Neohydronomous affinis Hustache (Coleoptera: Curculionidae) to control water lettuce, Pistia stratiotes Lilmaeus (Araceae) in the Tano River and Lagoon complex. Although these projects have been regarded as successful, they have relied on research from elsewhere in the world and no postrelease quantification has been conducted. In evaluating the impact of the biological control agents Neochetina bruchi and Neochetina eichhorniae weevils on water hyacinth infestations in the Tano River, fresh adult feeding scars were recorded as well as the numbers of adult weevils on each water hyacinth plant sampled at six sites. Despite being released in 1994, weevil numbers and resultant damage to plants in the Tano Lagoon was low in comparison to other regions of the world where these agents have been used. The main reason for this is that this lagoon floods seasonally, washing weevil-infested plants out to sea. Water hyacinth then re-infests the lagoon from seed and the weevil populations are low. To resolve this situation, two courses of action are proposed. The first is to mass rear the weevils along the shore of the lagoon and release them when the first seedlings recruit. The second proposal is that additional agents that have shorter lifecycies and are more mobile than the weevils should be released. To this end, the water hyacinth mirid, Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae) was imported from South Africa and released onto the Tano Lagoon in 2009. Retrospective laboratory host specificity trials were conducted on Neachetina eichharniae and Neachetina bruchi weevils 15 years after their release into Ghana to see if any variation in their host ranges had occurred. Considerable damage was inflicted on the E. crassipes leaves by the Neachetina weevils, while little feeding damage was recorded on both Heteranthera callifalia Kunth. (Pontederiaceae) and Eichharnia natans (P.Beauv.) Solms (Pontederiaceae). All the weevils introduced on H callifalia and E. natans died after the first week. This study served to confirm the host specificity and thereby the safety of these agents. Invasive alien aquatic macrophytes have negative impacts on the environment and economy of Ghana. The control of these weeds is essential to socioeconomic development and improved human health standards in riparian communities. Biological control offers a safe and sustainable control option, but requires diligent implementation. However, aquatic weed invasion is more typically a result of the anthropogenically induced eutrophication of water bodies, and this is the main issue that has to be addressed.
- Full Text:
- Date Issued: 2012
- Authors: Akpabey, Felix Jerry
- Date: 2012
- Subjects: Water hyacinth -- Control -- Environmental aspects -- Ghana Alien plants -- Research -- Ghana Introduced organisms Economic development -- Social aspects -- Research -- Ghana
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5748 , http://hdl.handle.net/10962/d1005435
- Description: The Akosombo Dam on the Volta River in Ghana was built in 1963 to provide cheap energy to fuel industry and to accelerate the economic growth of the country. It provides hydroelectric power, enhanced fishing and water transportation upstream, and improved opportunities for irrigated farming, especially in the lower reaches, and their attendant economic multiplier effects. A few years after the construction of this major dam, a rapid expansion of industrialization took place in Ghana. This brought about an exponential increase in demand for more electrical power. This led to the construction of a smaller dam at Akuse, downstream of the Akosomho Dam in 1981 and the formation of a headpond at Kpong. The impoundment of the river at the two sites (Akosombo and Kpong) caused an alteration in the existing ecological and biophysical processes in the river basin, including a slowing of the flow of the river, upstream and downstream. Changes in the natural processes, such as a reduction in the flow of the river and an increase in nutrient status of the water, resulted in an invasion of aquatic weeds, increasing the density of aquatic snails (intermediate hosts of schistosomiasis), silting and closure of the estuary, as well as other more subtle effects. The invasion of the river's main course and the dams by aquatic plants led to a corresponding reduction of navigable water both upstream and downstream. The aim of this thesis was to quantify the impact and control of waterweeds, especially water hyacinth, Eichhornia crassipes (Mart) Solms-Laubach (Pontederiaceae), in Ghana. A floral survey on the Kpong Headpond recorded 49 emergent, 12 free floating and I submerged aquatic plant species, many of which were indigenous, but the exotic or introduced water hyacinth was recorded at most of the sampling sites, and was the most abundant and had the biggest impact on the utilization of the water resource. Mats of water hyacinth served as substrates for other, indigenous species to grow out into the main channel of the headpond, including the intake point of the Kpong head works of the Ghana Water Company Limited (GWCL) and landing sites for boats. These mats resulted in a reduction of the fish (fin and shell) harvest, reducing the annual production to far below demand. Water hyacinth was also shown to have severe health implications. A survey of the Ministry of Health records showed that the prevalence of both urinary and intestinal schistosomiasis had risen significantly over time as the abundance of waterweeds, most notably water hyacinth, increased, and ranged between 70% and 75% but up to 100% in some lakeside communities. Based on the work done by an NGO on board the medical boat ("Onipa Nua "), losses in terms of money due to the effect on health of the aquatic weed infestations on the Volta River in 2006 amounted to US$ 620,000. Economic losses due to invasive alien aquatic weeds were also calculated on the Oti River Arm of Lake Volta. It was estimated that about US$2.3 million per annum would be lost to the Volta Lake Transport Company and individual boat transport operators if this section of the river were 100% covered by aquatic weeds (water hyacinth and Salvinia molesta D.S. Mitchell (Salviniaceae)). It was also estimated that US$327,038 was spent annually in monitoring and managing the weeds in the Oti River. Control interventions for aquatic weeds have been implemented in river systems in Ghana. The biological control agents Neochetina bruchi Hustache (Coleoptera, Curculionidae) and Neochetina eichhorniae Warner (Coleoptera, Curculionidae) have been used on water hyacinth infestations in the Oti River Arm of Lake Volta, the Tano River and the Lagoon complex in the south-western part of the country. Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) has been used to control salvinia, and Neohydronomous affinis Hustache (Coleoptera: Curculionidae) to control water lettuce, Pistia stratiotes Lilmaeus (Araceae) in the Tano River and Lagoon complex. Although these projects have been regarded as successful, they have relied on research from elsewhere in the world and no postrelease quantification has been conducted. In evaluating the impact of the biological control agents Neochetina bruchi and Neochetina eichhorniae weevils on water hyacinth infestations in the Tano River, fresh adult feeding scars were recorded as well as the numbers of adult weevils on each water hyacinth plant sampled at six sites. Despite being released in 1994, weevil numbers and resultant damage to plants in the Tano Lagoon was low in comparison to other regions of the world where these agents have been used. The main reason for this is that this lagoon floods seasonally, washing weevil-infested plants out to sea. Water hyacinth then re-infests the lagoon from seed and the weevil populations are low. To resolve this situation, two courses of action are proposed. The first is to mass rear the weevils along the shore of the lagoon and release them when the first seedlings recruit. The second proposal is that additional agents that have shorter lifecycies and are more mobile than the weevils should be released. To this end, the water hyacinth mirid, Eccritotarsus catarinensis (Carvalho) (Hemiptera: Miridae) was imported from South Africa and released onto the Tano Lagoon in 2009. Retrospective laboratory host specificity trials were conducted on Neachetina eichharniae and Neachetina bruchi weevils 15 years after their release into Ghana to see if any variation in their host ranges had occurred. Considerable damage was inflicted on the E. crassipes leaves by the Neachetina weevils, while little feeding damage was recorded on both Heteranthera callifalia Kunth. (Pontederiaceae) and Eichharnia natans (P.Beauv.) Solms (Pontederiaceae). All the weevils introduced on H callifalia and E. natans died after the first week. This study served to confirm the host specificity and thereby the safety of these agents. Invasive alien aquatic macrophytes have negative impacts on the environment and economy of Ghana. The control of these weeds is essential to socioeconomic development and improved human health standards in riparian communities. Biological control offers a safe and sustainable control option, but requires diligent implementation. However, aquatic weed invasion is more typically a result of the anthropogenically induced eutrophication of water bodies, and this is the main issue that has to be addressed.
- Full Text:
- Date Issued: 2012
Financial literacy training in the small, medium and microenterprises sector : effect on business growth in the Eastern Cape, South Africa
- Authors: Akpan, Iniobong Wilson
- Date: 2016
- Subjects: Economics Small business Business enterprises -- Finance
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10353/13608 , vital:39684
- Description: The centrality of financial literacy to business performance is increasingly becoming established in the literature, with several studies attributing business failures, especially in the small, medium and microenterprises (SMME) sector, to the failure of entrepreneurs to acquire needed levels of formal financial training. This emphasis represents a paradigm shift: small business failures were conventionally blamed on lack of access to capital, infrastructural deficits, lack of markets for SMME goods and services, regulatory constraints, and crime. In South Africa, and elsewhere in the developing world, this new orthodoxy has spurned new policy interventions aimed at improving the financial literacy levels in the SMME sector. Such is the drive to entrench formal literacy provisioning in the SMME sector that some microcredit providers now bundle financial management training into their SMME loan packages. However, there is a dearth of empirical studies that demonstrate, in any conclusive way, the effect of financial literacy training on small business growth and sustainability. The question, therefore, about whether formal financial literacy training actually leads to significant improvements in turnover levels and growth appears to be answered more as advocacy rather than on the basis of empirical evidence. It is against the backdrop of these arguments that the thesis adopted a quasi experimental design to study the business performance of a sample of SMME entrepreneurs who had received financial literacy training (the “treatment group”) at least two years before the study’s commencement and those who had had no financial literacy training at all (the “control group”). The objective was to determine whether any differences in business growth could be attributed to exposure to formal financial management training or the lack thereof. A survey was conducted with 40 respondents from each of the two groups (n = 80). The survey was triangulated with in-depth interviews of a randomly selected sample 10 of SMME operators from each of the two groups. The interviews sought to uncover the entrepreneurs’ narratives regarding the sources and salience of financial literacy in the sector. The study was conducted among SMME operators in Port Elizabeth, East London and Mthatha – the Eastern Cape’s major centres of commerce and industry. Data estimation was conducted using the Difference In Difference (DID) estimation model to determine whether financial literacy training has had any effect on the turnover of training recipients’ businesses (the treatment group) over that of non-training recipients (the control group). Also, the DID coefficient was used as a growth rate indicator to determine whether growth has occurred in training recipients’ businesses over non-training recipients businesses as a result of having received financial literacy training. The Propensity Score Matching (PSM) was used to estimate the average treatment effect (ATE) and the average treatment effect on the treated (ATET). Quantile DID correlations with covariates were also run to reveal the relationship between turnover (a growth variable) and the covariates as possible influencers of firm performance. The key findings of the study were that based on the specific financial variables tested, some basic financial management knowledge existed among members of the two groups of SMME operators, but there was very minimal application of the knowledge in the day-to-day running of the business. Operators utilise both formal financial literacy training and informal knowledge sources in the operation of their businesses. The study also found that in comparison, the difference in turnover between the treatment and control group at follow-up period was significant at a P value of 0.000. This gave rise to an overall DID P value of 0.000 in the estimation. However, the significance was in favour of control group businesses as the business of respondents in the “control group” (with no financial literacy training) performed better than that of respondents in the “treatment group” (who had received financial literacy training). Finally, the study found that financial literacy training had no effect on the growth of businesses in the short term as the growth rate of turnover of the treatment group was lower than that of the control group and the difference between the two rates was significant at a P value of 0.025. Also, compared to itself, the change in turnover levels of the treatment group was not significant in the pre- and post-training periods as revealed by the PSM ATET estimation result. Minimal changes in turnover of the treatment group was not significant at a P value of 0.124. The study concludes from these findings that while financial literacy remains a salient factor in business, scholarship about the real significance of financial literacy training on small business performance in the short term stands on a relatively shaky empirical foundation, especially when viewed against the background that many SMME entrepreneurs also rely on informal knowledge sources to make everyday business decisions. The study thus highlights the imperative of ensuring that knowledge-related interventions in the SMME sector draws on both formal and informal sources of knowledge.
- Full Text:
- Date Issued: 2016
- Authors: Akpan, Iniobong Wilson
- Date: 2016
- Subjects: Economics Small business Business enterprises -- Finance
- Language: English
- Type: Thesis , Doctoral , DCom
- Identifier: http://hdl.handle.net/10353/13608 , vital:39684
- Description: The centrality of financial literacy to business performance is increasingly becoming established in the literature, with several studies attributing business failures, especially in the small, medium and microenterprises (SMME) sector, to the failure of entrepreneurs to acquire needed levels of formal financial training. This emphasis represents a paradigm shift: small business failures were conventionally blamed on lack of access to capital, infrastructural deficits, lack of markets for SMME goods and services, regulatory constraints, and crime. In South Africa, and elsewhere in the developing world, this new orthodoxy has spurned new policy interventions aimed at improving the financial literacy levels in the SMME sector. Such is the drive to entrench formal literacy provisioning in the SMME sector that some microcredit providers now bundle financial management training into their SMME loan packages. However, there is a dearth of empirical studies that demonstrate, in any conclusive way, the effect of financial literacy training on small business growth and sustainability. The question, therefore, about whether formal financial literacy training actually leads to significant improvements in turnover levels and growth appears to be answered more as advocacy rather than on the basis of empirical evidence. It is against the backdrop of these arguments that the thesis adopted a quasi experimental design to study the business performance of a sample of SMME entrepreneurs who had received financial literacy training (the “treatment group”) at least two years before the study’s commencement and those who had had no financial literacy training at all (the “control group”). The objective was to determine whether any differences in business growth could be attributed to exposure to formal financial management training or the lack thereof. A survey was conducted with 40 respondents from each of the two groups (n = 80). The survey was triangulated with in-depth interviews of a randomly selected sample 10 of SMME operators from each of the two groups. The interviews sought to uncover the entrepreneurs’ narratives regarding the sources and salience of financial literacy in the sector. The study was conducted among SMME operators in Port Elizabeth, East London and Mthatha – the Eastern Cape’s major centres of commerce and industry. Data estimation was conducted using the Difference In Difference (DID) estimation model to determine whether financial literacy training has had any effect on the turnover of training recipients’ businesses (the treatment group) over that of non-training recipients (the control group). Also, the DID coefficient was used as a growth rate indicator to determine whether growth has occurred in training recipients’ businesses over non-training recipients businesses as a result of having received financial literacy training. The Propensity Score Matching (PSM) was used to estimate the average treatment effect (ATE) and the average treatment effect on the treated (ATET). Quantile DID correlations with covariates were also run to reveal the relationship between turnover (a growth variable) and the covariates as possible influencers of firm performance. The key findings of the study were that based on the specific financial variables tested, some basic financial management knowledge existed among members of the two groups of SMME operators, but there was very minimal application of the knowledge in the day-to-day running of the business. Operators utilise both formal financial literacy training and informal knowledge sources in the operation of their businesses. The study also found that in comparison, the difference in turnover between the treatment and control group at follow-up period was significant at a P value of 0.000. This gave rise to an overall DID P value of 0.000 in the estimation. However, the significance was in favour of control group businesses as the business of respondents in the “control group” (with no financial literacy training) performed better than that of respondents in the “treatment group” (who had received financial literacy training). Finally, the study found that financial literacy training had no effect on the growth of businesses in the short term as the growth rate of turnover of the treatment group was lower than that of the control group and the difference between the two rates was significant at a P value of 0.025. Also, compared to itself, the change in turnover levels of the treatment group was not significant in the pre- and post-training periods as revealed by the PSM ATET estimation result. Minimal changes in turnover of the treatment group was not significant at a P value of 0.124. The study concludes from these findings that while financial literacy remains a salient factor in business, scholarship about the real significance of financial literacy training on small business performance in the short term stands on a relatively shaky empirical foundation, especially when viewed against the background that many SMME entrepreneurs also rely on informal knowledge sources to make everyday business decisions. The study thus highlights the imperative of ensuring that knowledge-related interventions in the SMME sector draws on both formal and informal sources of knowledge.
- Full Text:
- Date Issued: 2016
Between the 'sectional' and the 'national' : oil, grassroots discontent and civic discourse in Nigeria
- Authors: Akpan, Wilson Ndarake
- Date: 2006
- Subjects: Petroleum industry and trade -- Nigeria Revenue -- Nigeria Nigeria -- Social conditions Nigeria -- Economic conditions Niger River Delta (Nigeria) -- Environmental conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3294 , http://hdl.handle.net/10962/d1003082
- Description: This thesis examines the social character of petroleum-related grassroots struggles in Nigeria’s oil-producing region. It does this against the background of the dominant scholarly narratives that portray the struggles as: a) a disguised pursuit of an ethnic/sectional agenda, b) a 'minority rights' project, and c) a minority province’s protest against 'selective' environmental 'victimisation' by the majority ethnic nationalities. While the dominant scholarly analyses of the struggles are based on the activities of the better known activist organisations operating in the oil region, this thesis focuses primarily on the everyday 'grammar' of discontent and lived worlds of ordinary people vis-à-vis upstream petroleum operations and petroleum resource utilisation. The aim has been to gain an understanding of the forces driving community struggles in the oil region and their wider societal significance. Examined alongside the narratives of ordinary people are the legal/institutional framework for upstream petroleum operations and the operational practices of the oil-producing companies. Using primary data obtained through ethnography, focus group discussions, in-depth interviews and visual sociology, as well as relevant secondary data, the researcher constructs a discourse matrix, showing how grassroots narratives in selected oilproducing communities intersect with contemporary civic discourses in the wider Nigerian context. The thesis highlights the theoretical and policy difficulties that arise when the social basis of petroleum-related grassroots struggles and ordinary people’s narratives are explained using an essentialist idiom. It reveals, above all, the conditions under which so-called 'locale-specific' struggles in a multi-ethnic, oil-rich African country can become a campaign for the emancipation of ordinary people in the wider society. This research extends the existing knowledge on citizen mobilisation, extractive capitalism, transnational corporate behaviour, and Nigeria’s contemporary development predicament. It sheds light on some of the processes through which ordinary people are forcing upon the state a change agenda that could drive the country along a more socially sensitive development and democratisation trajectory.
- Full Text:
- Date Issued: 2006
- Authors: Akpan, Wilson Ndarake
- Date: 2006
- Subjects: Petroleum industry and trade -- Nigeria Revenue -- Nigeria Nigeria -- Social conditions Nigeria -- Economic conditions Niger River Delta (Nigeria) -- Environmental conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3294 , http://hdl.handle.net/10962/d1003082
- Description: This thesis examines the social character of petroleum-related grassroots struggles in Nigeria’s oil-producing region. It does this against the background of the dominant scholarly narratives that portray the struggles as: a) a disguised pursuit of an ethnic/sectional agenda, b) a 'minority rights' project, and c) a minority province’s protest against 'selective' environmental 'victimisation' by the majority ethnic nationalities. While the dominant scholarly analyses of the struggles are based on the activities of the better known activist organisations operating in the oil region, this thesis focuses primarily on the everyday 'grammar' of discontent and lived worlds of ordinary people vis-à-vis upstream petroleum operations and petroleum resource utilisation. The aim has been to gain an understanding of the forces driving community struggles in the oil region and their wider societal significance. Examined alongside the narratives of ordinary people are the legal/institutional framework for upstream petroleum operations and the operational practices of the oil-producing companies. Using primary data obtained through ethnography, focus group discussions, in-depth interviews and visual sociology, as well as relevant secondary data, the researcher constructs a discourse matrix, showing how grassroots narratives in selected oilproducing communities intersect with contemporary civic discourses in the wider Nigerian context. The thesis highlights the theoretical and policy difficulties that arise when the social basis of petroleum-related grassroots struggles and ordinary people’s narratives are explained using an essentialist idiom. It reveals, above all, the conditions under which so-called 'locale-specific' struggles in a multi-ethnic, oil-rich African country can become a campaign for the emancipation of ordinary people in the wider society. This research extends the existing knowledge on citizen mobilisation, extractive capitalism, transnational corporate behaviour, and Nigeria’s contemporary development predicament. It sheds light on some of the processes through which ordinary people are forcing upon the state a change agenda that could drive the country along a more socially sensitive development and democratisation trajectory.
- Full Text:
- Date Issued: 2006
The adoption of employee share ownership plans (ESOPs) in Nigeria
- Authors: Akponah, Voke Blessing
- Date: 2017
- Subjects: Employee ownership -- Nigeria , Profit-sharing -- Nigeria Management -- Employee participation -- Nigeria Nigeria -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13834 , vital:27312
- Description: This study investigated the factors that influence the adoption of ESOPs in Nigeria. Furthermore, the study investigated the influence of the adoption of ESOPs on organisational performance, employee retention and employee commitment. The study results reveal that trade union responsiveness, reforms, awareness of employee benefits and taxation implication positively influence the adoption of ESOPs based on transparency. The results in this study further reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and taxation implication effectively influence the adoption of ESOPs based on two-way communication. In addition, the study results reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and trust positively influence the adoption of ESOPs based on empowerment. The study further reveals that adoption of ESOPs based on transparency, two-way communication and empowerment leads to organisational performance, employee retention and employee commitment. This study, being the first of its kind in Nigeria, filled the gap that existed in the Nigerian literature in respect of the awareness and adoption of ESOPs. This study provides literature and theoretical model that can be used as a foundation by organisations and the government to start up the adoption of ESOPs. This study showed that ESOPs is beneficial to boost the economy, enhance desired organisational outcomes (organisational performance, employee retention and employee commitment) and meet the financial and retirement needs of employees. However, for organisations and employees to enjoy the full benefits of ESOPs, underlying forces such as, trade union responsiveness, takeovers, reforms, awareness of employee benefits, trusts and taxation implication must be taken into account. Furthermore, the adoption, implementation and operations of ESOPs will be successful management, trade union leaders and employees utilise strategies such as, transparency, two-way communication and empowerment.
- Full Text:
- Date Issued: 2017
- Authors: Akponah, Voke Blessing
- Date: 2017
- Subjects: Employee ownership -- Nigeria , Profit-sharing -- Nigeria Management -- Employee participation -- Nigeria Nigeria -- Economic aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/13834 , vital:27312
- Description: This study investigated the factors that influence the adoption of ESOPs in Nigeria. Furthermore, the study investigated the influence of the adoption of ESOPs on organisational performance, employee retention and employee commitment. The study results reveal that trade union responsiveness, reforms, awareness of employee benefits and taxation implication positively influence the adoption of ESOPs based on transparency. The results in this study further reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and taxation implication effectively influence the adoption of ESOPs based on two-way communication. In addition, the study results reveal that trade union responsiveness, takeovers, reforms, awareness of employee benefits and trust positively influence the adoption of ESOPs based on empowerment. The study further reveals that adoption of ESOPs based on transparency, two-way communication and empowerment leads to organisational performance, employee retention and employee commitment. This study, being the first of its kind in Nigeria, filled the gap that existed in the Nigerian literature in respect of the awareness and adoption of ESOPs. This study provides literature and theoretical model that can be used as a foundation by organisations and the government to start up the adoption of ESOPs. This study showed that ESOPs is beneficial to boost the economy, enhance desired organisational outcomes (organisational performance, employee retention and employee commitment) and meet the financial and retirement needs of employees. However, for organisations and employees to enjoy the full benefits of ESOPs, underlying forces such as, trade union responsiveness, takeovers, reforms, awareness of employee benefits, trusts and taxation implication must be taken into account. Furthermore, the adoption, implementation and operations of ESOPs will be successful management, trade union leaders and employees utilise strategies such as, transparency, two-way communication and empowerment.
- Full Text:
- Date Issued: 2017
Conflict related sexual violence against males:recognition by and responses of humanitarian organizations in Africa
- Authors: Akurut, Catherine
- Date: 2020
- Subjects: Male rape victims -- Africa , Gender in conflict management --Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46648 , vital:39605
- Description: The study investigated the knowledge, attitudes, and experiences of humanitarian service providers concerning the recognition of and response to the phenomenon of male victims of conflict-related sexual violence against males. Sources of literature in respect to the awareness, understanding, and recognition of conflict-related sexual violence against males were explored. Perceptions about the recognition of male victims were discovered. Response strategies available to male victims were explored through the experiences of humanitarian organisation representatives, including, inter alia, programme managers, gender-based violence advisers, protection officers and activists. Mechanisms to augment any existing practices to allow for the care of and support for male victims were examined. A qualitative research approach was used to explore the topic of this study. Data was collected using semi-structured interview questions that were developed. And document review was also used as the second means of data collection. The research participants were recruited using purposive sampling, which was complemented by snowballing until data saturation. Triangulation was used by combining the two data collection methods to avoid relying on one source. A narrative literature review was aimed to obtain further information about the phenomenon of conflict-related sexual violence against males.
- Full Text:
- Date Issued: 2020
- Authors: Akurut, Catherine
- Date: 2020
- Subjects: Male rape victims -- Africa , Gender in conflict management --Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/46648 , vital:39605
- Description: The study investigated the knowledge, attitudes, and experiences of humanitarian service providers concerning the recognition of and response to the phenomenon of male victims of conflict-related sexual violence against males. Sources of literature in respect to the awareness, understanding, and recognition of conflict-related sexual violence against males were explored. Perceptions about the recognition of male victims were discovered. Response strategies available to male victims were explored through the experiences of humanitarian organisation representatives, including, inter alia, programme managers, gender-based violence advisers, protection officers and activists. Mechanisms to augment any existing practices to allow for the care of and support for male victims were examined. A qualitative research approach was used to explore the topic of this study. Data was collected using semi-structured interview questions that were developed. And document review was also used as the second means of data collection. The research participants were recruited using purposive sampling, which was complemented by snowballing until data saturation. Triangulation was used by combining the two data collection methods to avoid relying on one source. A narrative literature review was aimed to obtain further information about the phenomenon of conflict-related sexual violence against males.
- Full Text:
- Date Issued: 2020
Scalable chemistry involving diazonium salts
- Authors: Akwi, Faith Mary
- Date: 2016
- Subjects: Azo compounds -- Synthesis , Chemical processes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/6909 , vital:21162
- Description: Herein an alternative approach aimed at reducing the cost of numbering up technique as a scale up strategy for chemical processes from the laboratory bench top to the industry is explored. The effect of increasing channel size on the reaction conversion of the synthesis of azo compounds is investigated. This was achieved via a systematic investigative understanding of the synthesis in microreactors where a proof of concept study was performed to determine the optimum reaction parameters in azo coupling reactions involving couplers with aminated or hydroxylated groups in Little Things Factory-MS microreactors (Channel diameter: 1.0 mm) It was found that at slightly alkaline conditions (pH 8.55) and at a temperature of 25 °C, excellent conversions were attained in the azo coupling reaction of the diazonium salt solution of 2,4-dimethylaniline to 2-naphthol. On the other hand, the azo coupling reaction of the diazonium salt solution of p-nitroaniline to diphenylamine was found to thrive at a pH of 5.71 and at a temperature of 25 °C. Using, these optimized reaction parameters, the in-situ and reactive quench of diazonium salts in LTF-MS microreactors was investigated where it was found that at a flow rate of 0.2 ml/min, 0.03 ml/min and 0.07 ml/min of diazotizable amine & HCl, sodium nitrite and coupler solutions respectively, a conversion of 98% is achieved in approximately 2.4 minutes. A library of azo compounds was thus generated under these reaction conditions from couplers with aminated or hydroxylated aromatic aromatic systems. The scaled up synthesis of these compounds in a homemade PTFE tubing (ID 1.5 mm) reactor system was thereafter investigated and comparable conversions were observed. Capitalizing on the benefits of a large surface area and the short molecular diffusion distances observed in microreactors, in-situ phase transfer catalyzed azo coupling reaction of diphenylamine to p-nitroaniline was also explored. In this investigation a rapid and easy optimization protocol that yielded a 99%, 22% and 33% conversion of diphenylamine, carbazole and triphenylamine respectively in approximately 2.4 minutes using Chemtrix microreactors was established. On increasing the microreactor channel internal diameter in the scaled up synthesis approach, it was found that a 0.5 mm increase in channel internal diameter does result in lower reaction conversions.
- Full Text:
- Date Issued: 2016
- Authors: Akwi, Faith Mary
- Date: 2016
- Subjects: Azo compounds -- Synthesis , Chemical processes
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/6909 , vital:21162
- Description: Herein an alternative approach aimed at reducing the cost of numbering up technique as a scale up strategy for chemical processes from the laboratory bench top to the industry is explored. The effect of increasing channel size on the reaction conversion of the synthesis of azo compounds is investigated. This was achieved via a systematic investigative understanding of the synthesis in microreactors where a proof of concept study was performed to determine the optimum reaction parameters in azo coupling reactions involving couplers with aminated or hydroxylated groups in Little Things Factory-MS microreactors (Channel diameter: 1.0 mm) It was found that at slightly alkaline conditions (pH 8.55) and at a temperature of 25 °C, excellent conversions were attained in the azo coupling reaction of the diazonium salt solution of 2,4-dimethylaniline to 2-naphthol. On the other hand, the azo coupling reaction of the diazonium salt solution of p-nitroaniline to diphenylamine was found to thrive at a pH of 5.71 and at a temperature of 25 °C. Using, these optimized reaction parameters, the in-situ and reactive quench of diazonium salts in LTF-MS microreactors was investigated where it was found that at a flow rate of 0.2 ml/min, 0.03 ml/min and 0.07 ml/min of diazotizable amine & HCl, sodium nitrite and coupler solutions respectively, a conversion of 98% is achieved in approximately 2.4 minutes. A library of azo compounds was thus generated under these reaction conditions from couplers with aminated or hydroxylated aromatic aromatic systems. The scaled up synthesis of these compounds in a homemade PTFE tubing (ID 1.5 mm) reactor system was thereafter investigated and comparable conversions were observed. Capitalizing on the benefits of a large surface area and the short molecular diffusion distances observed in microreactors, in-situ phase transfer catalyzed azo coupling reaction of diphenylamine to p-nitroaniline was also explored. In this investigation a rapid and easy optimization protocol that yielded a 99%, 22% and 33% conversion of diphenylamine, carbazole and triphenylamine respectively in approximately 2.4 minutes using Chemtrix microreactors was established. On increasing the microreactor channel internal diameter in the scaled up synthesis approach, it was found that a 0.5 mm increase in channel internal diameter does result in lower reaction conversions.
- Full Text:
- Date Issued: 2016
Effect of service and collaborative learning strategies on students’ environmental knowledge in selected junior secondary schools in Oyo State, Nigeria
- Authors: Alalade, Olufiropo Emmanuel
- Date: 2019
- Subjects: Service learning Environmental management
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/16602 , vital:40736
- Description: Though many strategies have helped in increasing students’ knowledge and awareness about environmental issues, yet, environmental challenges and problems are still on the increase in Nigeria. This may be due to the fact that environmental issues are controversial and require collaborative efforts of all citizens, especially school students. This study determined the effects of service learning and collaborative learning in social studies on Junior Secondary School students’ environmental literacy. It also explored the moderating effects of school location and gender. The study adopted a pretest-posttest, control group, quasiexperimental design. Multi-stage sampling technique was employed. Six (6) secondary schools that are co-educational from Ibadan were purposively selected based on presence of environmental challenges in their immediate environment. There were three (3) schools from Ibadan city (urban area of Ibadan) and three (3) from Ibadan less city (rural area of Ibadan). Seven hypotheses were tested at 0.05 level of significance. Five research instruments were used for the study, these were; Environmental Knowledge Test (EKT, r = 0.76), Environmental Attitude Questionnaire (EAQ, r = 0.85), Service Learning Guide (SLG, r = 0.71), Collaborative Learning Guide (CLG, r = 0.66) and Conventional Learning Guide (CLG, r = 0.73). Analysis of Covariance (ANCOVA) was used in testing the seven formulated hypotheses. Scheffé Post-hoc analysis was carried out to determine the source of significant effect of treatment. Significant interaction effect was described using graphical representation. All hypotheses were tested at P< .05 level of significance. The results revealed that there was a significant main effect of treatment (service and collaborative learning strategies) on junior secondary school students’ environmental knowledge (F(2,582) = 824.98; p<0.05, partial η2 = 0.739), with an effect of 73.9%. There was also a significant main effect of treatment (service and collaborative learning strategies) on junior secondary school students’ environmental attitude (F(2,582) = 1317.79; p<0.05, partial η2 = 0.819). The findings showed that there was a significant main effect of gender (male/female) on junior secondary school students’ environmental knowledge (F(1,582) = 3.99; p<0.05, v partial η2 = 0.007) but there was no significant main effect of school location (urban/rural) on junior secondary school students’ environmental knowledge (F(1,582) = 0.08; p>.05, partial η2 = 0.00). Based on these findings, it was recommended that teachers should adopt service learning and collaborative learning strategies in the teaching of environmental concepts and problems in Social Studies in order to improve students’ performance in Social Studies. Teachers should facilitate the use of service learning and collaborative learning strategies in schools to improve students’ environmental problem-solving skills and their achievement in the subject. Teaching institutions should not only include service learning and collaborative learning strategies in their curriculum but should endeavour to provide practical experience for pre-service teachers to be well grounded and equipped on the use of these strategies.
- Full Text:
- Date Issued: 2019
- Authors: Alalade, Olufiropo Emmanuel
- Date: 2019
- Subjects: Service learning Environmental management
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/16602 , vital:40736
- Description: Though many strategies have helped in increasing students’ knowledge and awareness about environmental issues, yet, environmental challenges and problems are still on the increase in Nigeria. This may be due to the fact that environmental issues are controversial and require collaborative efforts of all citizens, especially school students. This study determined the effects of service learning and collaborative learning in social studies on Junior Secondary School students’ environmental literacy. It also explored the moderating effects of school location and gender. The study adopted a pretest-posttest, control group, quasiexperimental design. Multi-stage sampling technique was employed. Six (6) secondary schools that are co-educational from Ibadan were purposively selected based on presence of environmental challenges in their immediate environment. There were three (3) schools from Ibadan city (urban area of Ibadan) and three (3) from Ibadan less city (rural area of Ibadan). Seven hypotheses were tested at 0.05 level of significance. Five research instruments were used for the study, these were; Environmental Knowledge Test (EKT, r = 0.76), Environmental Attitude Questionnaire (EAQ, r = 0.85), Service Learning Guide (SLG, r = 0.71), Collaborative Learning Guide (CLG, r = 0.66) and Conventional Learning Guide (CLG, r = 0.73). Analysis of Covariance (ANCOVA) was used in testing the seven formulated hypotheses. Scheffé Post-hoc analysis was carried out to determine the source of significant effect of treatment. Significant interaction effect was described using graphical representation. All hypotheses were tested at P< .05 level of significance. The results revealed that there was a significant main effect of treatment (service and collaborative learning strategies) on junior secondary school students’ environmental knowledge (F(2,582) = 824.98; p<0.05, partial η2 = 0.739), with an effect of 73.9%. There was also a significant main effect of treatment (service and collaborative learning strategies) on junior secondary school students’ environmental attitude (F(2,582) = 1317.79; p<0.05, partial η2 = 0.819). The findings showed that there was a significant main effect of gender (male/female) on junior secondary school students’ environmental knowledge (F(1,582) = 3.99; p<0.05, v partial η2 = 0.007) but there was no significant main effect of school location (urban/rural) on junior secondary school students’ environmental knowledge (F(1,582) = 0.08; p>.05, partial η2 = 0.00). Based on these findings, it was recommended that teachers should adopt service learning and collaborative learning strategies in the teaching of environmental concepts and problems in Social Studies in order to improve students’ performance in Social Studies. Teachers should facilitate the use of service learning and collaborative learning strategies in schools to improve students’ environmental problem-solving skills and their achievement in the subject. Teaching institutions should not only include service learning and collaborative learning strategies in their curriculum but should endeavour to provide practical experience for pre-service teachers to be well grounded and equipped on the use of these strategies.
- Full Text:
- Date Issued: 2019
A lean production approach to materials management in the Nigerian construction industry
- Authors: Albert, Idowu
- Date: 2020
- Subjects: Materials management , Lean manufacturing Construction industry -- Nigeria
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46008 , vital:39408
- Description: The Nigerian Construction Industry faces a problem of poor materials management that leads to, among other things, materials waste, poor quality of work, poor materials flow, project delay and cost overrun. Overcoming these challenges, requires the rethinking the current modus operandi of the Nigerian construction industry. One such method that has been espoused as having potential to improve materials management, and associated challenges is ‘lean production’. This research aimed at deciphering the lean approach to production management with a view of extracting its utility in enhancing materials management in the construction industry. The qualitative method of research inquiry that is rooted in the phenomenological paradigm was employed. The research activities included a comprehensive review of the related literature and study of selected cases. Abuja, the Federal capital territory of Nigeria was the selected geographical scope of the research. Ten case studies were purposefully selected for the study. The research instrument was a tick box used for direct observation. The study revealed that poor materials management has a negative effect on the materials management plan. Moreover, mixing of waste at the site, negates the effort for identification of materials waste streams, and makes it difficult to account for materials waste, as well as implementing a materials waste management policy on sites. The research also found that poor materials management has a significant effect (high, moderate or low) on materials waste, quality of work, materials flow, productivity, project delay, project profitability and accounting for materials. The research has developed a conceptual model for a lean production approach to materials management based on the results and informed by the theoretical framework. The study has achieved its aim of establishing an understanding of the lean production approach to materials management in the Nigerian construction industry. The study recommends that construction professionals should be well informed on the effects of poor materials management.
- Full Text:
- Date Issued: 2020
- Authors: Albert, Idowu
- Date: 2020
- Subjects: Materials management , Lean manufacturing Construction industry -- Nigeria
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46008 , vital:39408
- Description: The Nigerian Construction Industry faces a problem of poor materials management that leads to, among other things, materials waste, poor quality of work, poor materials flow, project delay and cost overrun. Overcoming these challenges, requires the rethinking the current modus operandi of the Nigerian construction industry. One such method that has been espoused as having potential to improve materials management, and associated challenges is ‘lean production’. This research aimed at deciphering the lean approach to production management with a view of extracting its utility in enhancing materials management in the construction industry. The qualitative method of research inquiry that is rooted in the phenomenological paradigm was employed. The research activities included a comprehensive review of the related literature and study of selected cases. Abuja, the Federal capital territory of Nigeria was the selected geographical scope of the research. Ten case studies were purposefully selected for the study. The research instrument was a tick box used for direct observation. The study revealed that poor materials management has a negative effect on the materials management plan. Moreover, mixing of waste at the site, negates the effort for identification of materials waste streams, and makes it difficult to account for materials waste, as well as implementing a materials waste management policy on sites. The research also found that poor materials management has a significant effect (high, moderate or low) on materials waste, quality of work, materials flow, productivity, project delay, project profitability and accounting for materials. The research has developed a conceptual model for a lean production approach to materials management based on the results and informed by the theoretical framework. The study has achieved its aim of establishing an understanding of the lean production approach to materials management in the Nigerian construction industry. The study recommends that construction professionals should be well informed on the effects of poor materials management.
- Full Text:
- Date Issued: 2020
Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) population ecology in citrus orchards: the influence of orchard age
- Authors: Albertyn, Sonnica
- Date: 2018
- Subjects: Cryptophlebia leucotreta , Population biology , Insect populations , Orchards , Insect nematodes , Entomopathogenic fungi
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62615 , vital:28213
- Description: Anecdotal reports in the South African citrus industry claim higher populations of false codling moth (FCM), Thaumatotibia (Cryptophlebia) leucotreta (Meyr) (Lepidoptera: Tortricidae), in orchards during the first three to five harvesting years of citrus planted in virgin soil, after which, FCM numbers seem to decrease and remain consistent. Various laboratory studies and field surveys were conducted to determine if, and why juvenile orchards (four to eight years old) experience higher FCM infestation than mature orchards (nine years and older). In laboratory trials, Washington Navel oranges and Nova Mandarins from juvenile trees were shown to be significantly more susceptible to FCM damage and significantly more attractive for oviposition in both choice and no-choice trials, than fruit from mature trees. Although fruit from juvenile Cambria Navel trees were significantly more attractive than mature orchards for oviposition, they were not more susceptible to FCM damage. In contrast, fruit from juvenile and mature Midnight Valencia orchards were equally attractive for oviposition, but fruit from juvenile trees were significantly more susceptible to FCM damage than fruit from mature trees. Artificial diets were augmented with powder from fruit from juvenile or mature Washington Navel orchards at 5%, 10%, 15% or 30%. Higher larval survival of 76%, 63%, 50% and 34%, respectively, was recorded on diets containing fruit powder from the juvenile trees than on diets containing fruit powder from the mature trees, at 69%, 57%, 44% and 27% larval survival, respectively. Bioassays were conducted to determine if differences in plant chemistry between fruit from juvenile and mature trees will have an impact on the susceptibility FCM to entomopathogenic nematodes (EPN), entomopathogenic fungi (EPF) and Cryptophlebia leucotreta granulovirus (CrleGV). No significant differences in the susceptibility of larvae reared on diets containing 15% fruit powder from juvenile and mature trees to EPN and EPF were recorded. Mortality of neonate larvae was significantly lower when placed on diets containing 15% fruit powder from mature trees (45% mortality) than diets containing 15% fruit powder from juvenile trees (61% mortality), after larvae ingested the lowest virus concentration tested, being 2 x104 OBs/ml. Data collected from field surveys showed significantly lower egg parasitism, virus infection of larvae and EPF occurrence in juvenile orchards than mature orchards. Egg parasitism was between 11% and 54% higher in mature orchards than juvenile orchards, with the exception of Mandarins during 2015, where egg parasitism was slightly higher in juvenile orchards, but not significantly so. A significantly higher proportion of larvae retrieved from mature orchards (7% of larvae) were infected with CrleGV than larvae retrieved from juvenile orchards (4% of larvae). A significantly higher occurrence of EPF was recorded in non-bearing and mature orchards, with 40% and 37% occurrence respectively, than in juvenile orchards, with 25% occurrence recorded. EPF occurrence in juvenile orchards increased significantly by 16% to 32% from the first to the third year of sampling. In contrast to results recorded in laboratory trials, similar or higher pest pressure in juvenile orchards than mature orchards did not always result in significantly higher levels of FCM damage under field conditions. FCM damage in juvenile orchards may have been lower than expected, as greater extremes of temperature and lower humidity were recorded in juvenile orchards, which would increase larval mortality. Results of this study showed that juvenile and mature orchards are significantly different and should be managed differently.
- Full Text:
- Date Issued: 2018
- Authors: Albertyn, Sonnica
- Date: 2018
- Subjects: Cryptophlebia leucotreta , Population biology , Insect populations , Orchards , Insect nematodes , Entomopathogenic fungi
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62615 , vital:28213
- Description: Anecdotal reports in the South African citrus industry claim higher populations of false codling moth (FCM), Thaumatotibia (Cryptophlebia) leucotreta (Meyr) (Lepidoptera: Tortricidae), in orchards during the first three to five harvesting years of citrus planted in virgin soil, after which, FCM numbers seem to decrease and remain consistent. Various laboratory studies and field surveys were conducted to determine if, and why juvenile orchards (four to eight years old) experience higher FCM infestation than mature orchards (nine years and older). In laboratory trials, Washington Navel oranges and Nova Mandarins from juvenile trees were shown to be significantly more susceptible to FCM damage and significantly more attractive for oviposition in both choice and no-choice trials, than fruit from mature trees. Although fruit from juvenile Cambria Navel trees were significantly more attractive than mature orchards for oviposition, they were not more susceptible to FCM damage. In contrast, fruit from juvenile and mature Midnight Valencia orchards were equally attractive for oviposition, but fruit from juvenile trees were significantly more susceptible to FCM damage than fruit from mature trees. Artificial diets were augmented with powder from fruit from juvenile or mature Washington Navel orchards at 5%, 10%, 15% or 30%. Higher larval survival of 76%, 63%, 50% and 34%, respectively, was recorded on diets containing fruit powder from the juvenile trees than on diets containing fruit powder from the mature trees, at 69%, 57%, 44% and 27% larval survival, respectively. Bioassays were conducted to determine if differences in plant chemistry between fruit from juvenile and mature trees will have an impact on the susceptibility FCM to entomopathogenic nematodes (EPN), entomopathogenic fungi (EPF) and Cryptophlebia leucotreta granulovirus (CrleGV). No significant differences in the susceptibility of larvae reared on diets containing 15% fruit powder from juvenile and mature trees to EPN and EPF were recorded. Mortality of neonate larvae was significantly lower when placed on diets containing 15% fruit powder from mature trees (45% mortality) than diets containing 15% fruit powder from juvenile trees (61% mortality), after larvae ingested the lowest virus concentration tested, being 2 x104 OBs/ml. Data collected from field surveys showed significantly lower egg parasitism, virus infection of larvae and EPF occurrence in juvenile orchards than mature orchards. Egg parasitism was between 11% and 54% higher in mature orchards than juvenile orchards, with the exception of Mandarins during 2015, where egg parasitism was slightly higher in juvenile orchards, but not significantly so. A significantly higher proportion of larvae retrieved from mature orchards (7% of larvae) were infected with CrleGV than larvae retrieved from juvenile orchards (4% of larvae). A significantly higher occurrence of EPF was recorded in non-bearing and mature orchards, with 40% and 37% occurrence respectively, than in juvenile orchards, with 25% occurrence recorded. EPF occurrence in juvenile orchards increased significantly by 16% to 32% from the first to the third year of sampling. In contrast to results recorded in laboratory trials, similar or higher pest pressure in juvenile orchards than mature orchards did not always result in significantly higher levels of FCM damage under field conditions. FCM damage in juvenile orchards may have been lower than expected, as greater extremes of temperature and lower humidity were recorded in juvenile orchards, which would increase larval mortality. Results of this study showed that juvenile and mature orchards are significantly different and should be managed differently.
- Full Text:
- Date Issued: 2018
A linguistic account of quantifiers in English and their place in the development of some modern approaches to syntax and semantics
- Authors: Aldridge, Maurice Vincent
- Date: 1977
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20966 , http://hdl.handle.net/10962/5707
- Description: From Introduction: I should make it clear from the outset that I have no intention of trying to construct a calculus for the quantificational system of English as a natural language. My interests are purely linguistic with special emphasis on that part of the discipline traditionally known as semantics. Thus, although I offer a miniature survey of the development of quantificational studies in Philosophy in Chapter One, and have frequent recourse, in other charters, to observations made by philosophers, especially Quine, I make no attempt whatever to emulate the logicians by constructing such things as rules of inference. I have also tried to avoid symbolic representations except in those cases in which they show up aspects of semantic structure very clearly, and where I have symbolised, I have alternated between the systems of Quine and Peano-Russell, selection in each instance being determined by judgements regarding clarity.
- Full Text:
- Date Issued: 1977
- Authors: Aldridge, Maurice Vincent
- Date: 1977
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20966 , http://hdl.handle.net/10962/5707
- Description: From Introduction: I should make it clear from the outset that I have no intention of trying to construct a calculus for the quantificational system of English as a natural language. My interests are purely linguistic with special emphasis on that part of the discipline traditionally known as semantics. Thus, although I offer a miniature survey of the development of quantificational studies in Philosophy in Chapter One, and have frequent recourse, in other charters, to observations made by philosophers, especially Quine, I make no attempt whatever to emulate the logicians by constructing such things as rules of inference. I have also tried to avoid symbolic representations except in those cases in which they show up aspects of semantic structure very clearly, and where I have symbolised, I have alternated between the systems of Quine and Peano-Russell, selection in each instance being determined by judgements regarding clarity.
- Full Text:
- Date Issued: 1977
The evaluation of an instructional framework using the Van Hiele levels for learning and teaching geometry: a study in five rural senior secondary schools
- Alex, Jogymol Kalariparampil
- Authors: Alex, Jogymol Kalariparampil
- Date: 2012
- Subjects: Teaching and learning -- Geometry -- Education (Secondary)
- Language: English
- Type: Thesis , Doctoral , D Ed
- Identifier: vital:18470 , http://hdl.handle.net/11260/d1011278
- Description: The Constitution (1996) of the Republic of South Africa forms the basis for social transformation in our new society. The Constitution (Act 108 of 1996) and the amendments that followed provided a basis for curriculum transformation and development in South Africa. The Department of Education introduced the present curriculum known as the National Curriculum Statement, which is modern and internationally benchmarked, in grade 10 in 2006. It required the learners to do seven subjects in grades 10 to 12 of which mathematics or mathematical literacy was prescribed as compulsory subjects. To attain social transformation, the South African Government attached a great deal of importance to the learning and teaching of mathematics and sciences in the South African schools. This study was undertaken in an effort to improve the understanding of geometry and, consequently, the performance and achievement of senior secondary school learners in geometry. The study was inspired by the van Hiele theory. The study made use of the different levels of the van Hiele theory for the development of an instructional framework for geometry in senior secondary schools. The research was conducted in a previously disadvantaged area in South Africa. Given the setting of this study and the wider application of it, the use of ‘hands-on’ and practical approach to use manipulatives and worksheets to improve the geometric understanding was tried and tested in this study. The assumption was that such experiences would make the learning of geometry more relevant and enjoyable for learners from limited financial and underprivileged circumstances. A quasi-experimental design was chosen. A total of 359 learners from five purposively selected schools in Mthatha district in the Eastern Cape Province participated in this study. Qualitative data through interviews were gathered. The data were analysed using IBM SPSS Version 19 and Microsoft Excel. Findings indicated that there was a notable improvement in the performance of learners who were taught by the application of the van Hiele theory. The results revealed that most of the learners were not ready for the application of deductive principles of geometry in terms of formal proof in senior secondary school geometry. Based on the results, some recommendations are made to enhance the teaching and learning of geometry in senior secondary schools.
- Full Text:
- Date Issued: 2012
- Authors: Alex, Jogymol Kalariparampil
- Date: 2012
- Subjects: Teaching and learning -- Geometry -- Education (Secondary)
- Language: English
- Type: Thesis , Doctoral , D Ed
- Identifier: vital:18470 , http://hdl.handle.net/11260/d1011278
- Description: The Constitution (1996) of the Republic of South Africa forms the basis for social transformation in our new society. The Constitution (Act 108 of 1996) and the amendments that followed provided a basis for curriculum transformation and development in South Africa. The Department of Education introduced the present curriculum known as the National Curriculum Statement, which is modern and internationally benchmarked, in grade 10 in 2006. It required the learners to do seven subjects in grades 10 to 12 of which mathematics or mathematical literacy was prescribed as compulsory subjects. To attain social transformation, the South African Government attached a great deal of importance to the learning and teaching of mathematics and sciences in the South African schools. This study was undertaken in an effort to improve the understanding of geometry and, consequently, the performance and achievement of senior secondary school learners in geometry. The study was inspired by the van Hiele theory. The study made use of the different levels of the van Hiele theory for the development of an instructional framework for geometry in senior secondary schools. The research was conducted in a previously disadvantaged area in South Africa. Given the setting of this study and the wider application of it, the use of ‘hands-on’ and practical approach to use manipulatives and worksheets to improve the geometric understanding was tried and tested in this study. The assumption was that such experiences would make the learning of geometry more relevant and enjoyable for learners from limited financial and underprivileged circumstances. A quasi-experimental design was chosen. A total of 359 learners from five purposively selected schools in Mthatha district in the Eastern Cape Province participated in this study. Qualitative data through interviews were gathered. The data were analysed using IBM SPSS Version 19 and Microsoft Excel. Findings indicated that there was a notable improvement in the performance of learners who were taught by the application of the van Hiele theory. The results revealed that most of the learners were not ready for the application of deductive principles of geometry in terms of formal proof in senior secondary school geometry. Based on the results, some recommendations are made to enhance the teaching and learning of geometry in senior secondary schools.
- Full Text:
- Date Issued: 2012
Contributions to the biology, anatomy and physiology of Opisthophthalmus Latimanus & other scorpions
- Authors: Alexander, Anne Joy
- Date: 1958
- Subjects: Scorpions -- South Africa , Scorpions -- Anatomy , Scorpions -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5891 , http://hdl.handle.net/10962/d1013375
- Description: [From Introduction] For many years the problem of interrelationships within the Arthropoda and, indeed, the origin of the Phylum itself have been of interest to many zoologists. It was felt, for reasons which will be given later, that one of the studies which might throw some light on this matter is that of the neuromuscular physiology of arachnid appendages. Consequently it was proposed that the work which is reported here should be primarily concerned with this problem. As in so many cases involving live animals, both the experimental subjects and the experimenter gradually managed to change the direction in which work was proceeding and the result is that only a preliminary attack has been made on the original problem, while most of the material submitted here deals either with functional anatomy or with biological-cum-behavioural characteristics of the experimental animal. Thus it was found that to develop experimental preparations for neuro-muscular studies, it was necessary to work out the anatomy of the muscles and nerves of the appendages used; but this it is not enough. For these nerves and muscles are part of a functional complex which operates as a unit and have therefore to be studied in relation to the structures that they move. Considerations at this level, in fact, carried the study to the plane of functional anatomy. Furthermore it was recognised that even the comprehension of a limb as a functional complex cannot be acquired in isolation. All structures have an evolutionary history and in any consideration of functional anatomy this history must be taken into account - even if the consideration requires extension to the problem of the origin of the group immediately under study.
- Full Text:
- Date Issued: 1958
Contributions to the biology, anatomy and physiology of Opisthophthalmus Latimanus & other scorpions
- Authors: Alexander, Anne Joy
- Date: 1958
- Subjects: Scorpions -- South Africa , Scorpions -- Anatomy , Scorpions -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5891 , http://hdl.handle.net/10962/d1013375
- Description: [From Introduction] For many years the problem of interrelationships within the Arthropoda and, indeed, the origin of the Phylum itself have been of interest to many zoologists. It was felt, for reasons which will be given later, that one of the studies which might throw some light on this matter is that of the neuromuscular physiology of arachnid appendages. Consequently it was proposed that the work which is reported here should be primarily concerned with this problem. As in so many cases involving live animals, both the experimental subjects and the experimenter gradually managed to change the direction in which work was proceeding and the result is that only a preliminary attack has been made on the original problem, while most of the material submitted here deals either with functional anatomy or with biological-cum-behavioural characteristics of the experimental animal. Thus it was found that to develop experimental preparations for neuro-muscular studies, it was necessary to work out the anatomy of the muscles and nerves of the appendages used; but this it is not enough. For these nerves and muscles are part of a functional complex which operates as a unit and have therefore to be studied in relation to the structures that they move. Considerations at this level, in fact, carried the study to the plane of functional anatomy. Furthermore it was recognised that even the comprehension of a limb as a functional complex cannot be acquired in isolation. All structures have an evolutionary history and in any consideration of functional anatomy this history must be taken into account - even if the consideration requires extension to the problem of the origin of the group immediately under study.
- Full Text:
- Date Issued: 1958
Participatory mapping, learning and change in the context of biocultural diversity and resilience
- Authors: Ali, Million Belay
- Date: 2012
- Subjects: Biodiversity conservation -- Research -- Ethiopia Cultural pluralism -- Research -- Ethiopia Ethnopsychology -- Research -- Ethiopia Adult education -- Research -- Ethiopia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1689 , http://hdl.handle.net/10962/d1003572
- Description: This study set out to investigate the learning and change that emerged in and through participatory mapping in the context of biocultural diversity and resilience in rural Ethiopia. It did this through examining the learning and agency emerging from three participatory mapping practices (Participatory 3 Dimensional Modelling, sketch mapping and eco-cultural calendars) using two case study sites, located in the Bale Mountains and the Foata Mountains in Ethiopia, and honing in on in-depth reflective processes in two community contexts located within the broader case study sites, namely Horo Soba, Dinsho wereda in Bale; and Telecho, in Wolmera wereda, in the Foata Mountain complex. This study tried to answer three research questions related to participatory mapping: its role in mobilizing knowledge related to biocultural landscape, its role in learning and change, and its value in building resilience. The study used qualitative case study research methodology underpinned by critical realist philosophy, and used photographic ‘cues’ to structure the reporting on the cases. It used four categories of analysis: biocultural diversity, educational processes, learning and agency, in the first instance to report on the interactions associated with the participatory mapping practices as they emerged in the two case study sites. This was followed by in-depth analysis and interpretation of participatory mapping and biocultural diversity, as well as participatory mapping and learning, with an emphasis on acquisition, meaning making and identity formation processes. The in-depth analysis drew on social and learning theory, and theory of biocultural diversity and social-ecological resilience. The study also included analysis of broader change processes that were related to and emerged from the social interactions in the mapping activities, and the resultant morphogenesis (change), showing that morphogenesis, while broadly temporal, is not linear, and involves ‘little iterative morphogenic cycles’. These insights were then used to interpret how participatory mapping may contribute to resilience building in a context where social-ecological resilience is increasingly required, such as the two case study sites, where socialecological degradation is highly visible and is occurring rapidly. The study’s contribution to new knowledge lies in relation to the role of participatory mapping in facilitating learning, agency and change which, to date, appears to be under-theorised and under-developed in the participatory mapping and environmental education literature. As such, the study findings provide in-depth insight into how participatory mapping methodologies may ‘work in the world’, in contexts such as those presented in the two cases under study. It has tried to demonstrate how participatory mapping has managed to mobilize knowledge related to biocultural diversity, facilitated the acquisition of knowledge and helped members of the community to engage in meaning making activities relevant to their biocultural landscape and renegotiate their identity within the wider community context. It has also shown that dissonance is an important dynamic in the learning process; and that morphogenesis (or change) occurs over time, but also in smaller cycles that interact at different levels; and that participatory mapping cannot, by itself mobilise significant structural change, at least in the short term. It has also shown, however, that learning and the desire for change can emerge from participatory mapping processes, and that this can be utilized to adapt to the changing socio-ecological environments, potentially contributing to longer term resilience of social-ecological systems.
- Full Text:
- Date Issued: 2012
- Authors: Ali, Million Belay
- Date: 2012
- Subjects: Biodiversity conservation -- Research -- Ethiopia Cultural pluralism -- Research -- Ethiopia Ethnopsychology -- Research -- Ethiopia Adult education -- Research -- Ethiopia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1689 , http://hdl.handle.net/10962/d1003572
- Description: This study set out to investigate the learning and change that emerged in and through participatory mapping in the context of biocultural diversity and resilience in rural Ethiopia. It did this through examining the learning and agency emerging from three participatory mapping practices (Participatory 3 Dimensional Modelling, sketch mapping and eco-cultural calendars) using two case study sites, located in the Bale Mountains and the Foata Mountains in Ethiopia, and honing in on in-depth reflective processes in two community contexts located within the broader case study sites, namely Horo Soba, Dinsho wereda in Bale; and Telecho, in Wolmera wereda, in the Foata Mountain complex. This study tried to answer three research questions related to participatory mapping: its role in mobilizing knowledge related to biocultural landscape, its role in learning and change, and its value in building resilience. The study used qualitative case study research methodology underpinned by critical realist philosophy, and used photographic ‘cues’ to structure the reporting on the cases. It used four categories of analysis: biocultural diversity, educational processes, learning and agency, in the first instance to report on the interactions associated with the participatory mapping practices as they emerged in the two case study sites. This was followed by in-depth analysis and interpretation of participatory mapping and biocultural diversity, as well as participatory mapping and learning, with an emphasis on acquisition, meaning making and identity formation processes. The in-depth analysis drew on social and learning theory, and theory of biocultural diversity and social-ecological resilience. The study also included analysis of broader change processes that were related to and emerged from the social interactions in the mapping activities, and the resultant morphogenesis (change), showing that morphogenesis, while broadly temporal, is not linear, and involves ‘little iterative morphogenic cycles’. These insights were then used to interpret how participatory mapping may contribute to resilience building in a context where social-ecological resilience is increasingly required, such as the two case study sites, where socialecological degradation is highly visible and is occurring rapidly. The study’s contribution to new knowledge lies in relation to the role of participatory mapping in facilitating learning, agency and change which, to date, appears to be under-theorised and under-developed in the participatory mapping and environmental education literature. As such, the study findings provide in-depth insight into how participatory mapping methodologies may ‘work in the world’, in contexts such as those presented in the two cases under study. It has tried to demonstrate how participatory mapping has managed to mobilize knowledge related to biocultural diversity, facilitated the acquisition of knowledge and helped members of the community to engage in meaning making activities relevant to their biocultural landscape and renegotiate their identity within the wider community context. It has also shown that dissonance is an important dynamic in the learning process; and that morphogenesis (or change) occurs over time, but also in smaller cycles that interact at different levels; and that participatory mapping cannot, by itself mobilise significant structural change, at least in the short term. It has also shown, however, that learning and the desire for change can emerge from participatory mapping processes, and that this can be utilized to adapt to the changing socio-ecological environments, potentially contributing to longer term resilience of social-ecological systems.
- Full Text:
- Date Issued: 2012
Trophodynamics of the benthic and hyperbenthic communities inhabiting the Sub-Antarctic Prince Edward Islands : stable isotope and fatty acid signatures
- Authors: Allan, Elizabeth Louise
- Date: 2011
- Subjects: Benthos -- Prince Edward Islands Benthos -- Feeding and feeds -- Prince Edward Islands Benthos -- Nutrition -- Prince Edward Islands Prince Edward Islands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5806 , http://hdl.handle.net/10962/d1006350
- Description: The aim of this study was to investigate spatial changes in the trophic and energy pathways of the benthic community in the shallow shelf waters of the sub-Antarctic Prince Edward Islands (PEI). A combination of stable isotope and fatty acid analyses were used to provide a time-integrated view of the assimilated feeding history of selected components of the PEI benthic community. This study forms part of the larger project entitled “Variability in the Southern Ocean ecosystems” and is a contribution to the South African National Antarctic Programme (SANAP). During austral autumn 2009, benthic specimens were collected from 10 stations (from depths of 70 to 295 m) in different regions around the PEI: inter-island shelf (upstream, between and downstream of the islands) and nearshore. Historical data were combined with new data collected during 2009 to assess the long-term trends in the feeding ecology of the benthos in the region of the islands. The stable isotope and fatty acid signatures of the benthic suspension- and deposit-feeding organisms generated during this study suggested that these two communities incorporated both phytoplankton and kelp in their diets. Stable isotope, and to a lesser extent fatty acid signatures, indicated that kelp contributed more to the diets of those organisms in close proximity to the kelp beds (nearshore stations) than those from the inter-island region. Overall, however, pelagic phytoplankton was the dominant food source in the diets of all organisms, even for those living near the kelp beds. Notable exceptions were the sponges and bryozoans, in which kelp and phytoplankton contributed similar proportions to their diets, most likely resulting from a size restricted feeding mode. There were, therefore, no distinct spatial differences in the importance of the various food sources. However, fatty acid compositional data indicated increased food quality between and within the lee of the islands compared to upstream. The organisms collected upstream of the PEI had substantially lower quantities of total fatty acids (TFAs) than organisms of the same species collected from nearshore, open shelf or downstream stations. The increased food quality between and within the lee of the islands was likely a result of the “island mass effect”, which reflects increased phytoplankton concentrations at the PEI. The fatty acid profiles of hyperbenthic shrimp Nauticaris marionis, a key species in the PEI ecosystem, revealed no distinct ontogenetic or spatial patterns. This result is in contrast to the stable isotope analyses, which detected both spatial and ontogenetic differences in the diet of the shrimp. Nearshore shrimp were more ₁₃C-enriched than those from the inter-island region, suggesting increased kelp entering the food web within these regions. In addition, the shrimps demonstrated enrichment in δ₁₃C and δ₁₅N signatures with an increase in size, resulting in a relatively distinct separation of size classes, thus reflecting niche separation through their diets. The fatty acid profiles revealed that the shrimp all contained large proportions of polyunsaturated fatty acids (PUFAs) and essential fatty acids (EFAs), indicating that the quality of food consumed was similar among size class and region despite the niche separation and variation in carbon sources utilised. In addition, diatom and dinoflagellate fatty acids (20:5ω3 and 22:6ω3, respectively) occurred in the highest proportions in N. marionis, highlighting the importance of phytoplankton (indirectly) in their diet. These results represent strong evidence that phytoplankton is an importance food source in the PEI ecosystem. The temporal investigation of isotope signatures in the benthos at the PEI indicated that N. marionis demonstrated an overall depletion in δ₁₃C signatures over the period of 1984 to 2009 (nearshore: -2.55 ‰, inter-island: -2.32 ‰). Overall, the benthic community showed similar depletions in δ13C signatures (from -1.96 to -4.70 ‰), suggesting that shifts have occurred in the carbon signatures at the base of the food web. The depletion in δ₁₃C signatures of the benthos at the PEI most likely reflects increased contributions of smaller slow growing phytoplankton cells (more depleted signatures than large fast growing cells) in the diets of these organisms over time. These diet shifts, in turn, suggest a decrease in productivity has occurred at the islands, likely due to a decreased frequency and intensity of the “island mass effect”. Decreased phytoplankton productivity at the PEI likely results from the southward shift in the average position of the sub-Antarctic Front (SAF), most likely in response to climate change, which in turn promotes flow-through conditions rather than retention at the PEI.
- Full Text:
- Date Issued: 2011
- Authors: Allan, Elizabeth Louise
- Date: 2011
- Subjects: Benthos -- Prince Edward Islands Benthos -- Feeding and feeds -- Prince Edward Islands Benthos -- Nutrition -- Prince Edward Islands Prince Edward Islands
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5806 , http://hdl.handle.net/10962/d1006350
- Description: The aim of this study was to investigate spatial changes in the trophic and energy pathways of the benthic community in the shallow shelf waters of the sub-Antarctic Prince Edward Islands (PEI). A combination of stable isotope and fatty acid analyses were used to provide a time-integrated view of the assimilated feeding history of selected components of the PEI benthic community. This study forms part of the larger project entitled “Variability in the Southern Ocean ecosystems” and is a contribution to the South African National Antarctic Programme (SANAP). During austral autumn 2009, benthic specimens were collected from 10 stations (from depths of 70 to 295 m) in different regions around the PEI: inter-island shelf (upstream, between and downstream of the islands) and nearshore. Historical data were combined with new data collected during 2009 to assess the long-term trends in the feeding ecology of the benthos in the region of the islands. The stable isotope and fatty acid signatures of the benthic suspension- and deposit-feeding organisms generated during this study suggested that these two communities incorporated both phytoplankton and kelp in their diets. Stable isotope, and to a lesser extent fatty acid signatures, indicated that kelp contributed more to the diets of those organisms in close proximity to the kelp beds (nearshore stations) than those from the inter-island region. Overall, however, pelagic phytoplankton was the dominant food source in the diets of all organisms, even for those living near the kelp beds. Notable exceptions were the sponges and bryozoans, in which kelp and phytoplankton contributed similar proportions to their diets, most likely resulting from a size restricted feeding mode. There were, therefore, no distinct spatial differences in the importance of the various food sources. However, fatty acid compositional data indicated increased food quality between and within the lee of the islands compared to upstream. The organisms collected upstream of the PEI had substantially lower quantities of total fatty acids (TFAs) than organisms of the same species collected from nearshore, open shelf or downstream stations. The increased food quality between and within the lee of the islands was likely a result of the “island mass effect”, which reflects increased phytoplankton concentrations at the PEI. The fatty acid profiles of hyperbenthic shrimp Nauticaris marionis, a key species in the PEI ecosystem, revealed no distinct ontogenetic or spatial patterns. This result is in contrast to the stable isotope analyses, which detected both spatial and ontogenetic differences in the diet of the shrimp. Nearshore shrimp were more ₁₃C-enriched than those from the inter-island region, suggesting increased kelp entering the food web within these regions. In addition, the shrimps demonstrated enrichment in δ₁₃C and δ₁₅N signatures with an increase in size, resulting in a relatively distinct separation of size classes, thus reflecting niche separation through their diets. The fatty acid profiles revealed that the shrimp all contained large proportions of polyunsaturated fatty acids (PUFAs) and essential fatty acids (EFAs), indicating that the quality of food consumed was similar among size class and region despite the niche separation and variation in carbon sources utilised. In addition, diatom and dinoflagellate fatty acids (20:5ω3 and 22:6ω3, respectively) occurred in the highest proportions in N. marionis, highlighting the importance of phytoplankton (indirectly) in their diet. These results represent strong evidence that phytoplankton is an importance food source in the PEI ecosystem. The temporal investigation of isotope signatures in the benthos at the PEI indicated that N. marionis demonstrated an overall depletion in δ₁₃C signatures over the period of 1984 to 2009 (nearshore: -2.55 ‰, inter-island: -2.32 ‰). Overall, the benthic community showed similar depletions in δ13C signatures (from -1.96 to -4.70 ‰), suggesting that shifts have occurred in the carbon signatures at the base of the food web. The depletion in δ₁₃C signatures of the benthos at the PEI most likely reflects increased contributions of smaller slow growing phytoplankton cells (more depleted signatures than large fast growing cells) in the diets of these organisms over time. These diet shifts, in turn, suggest a decrease in productivity has occurred at the islands, likely due to a decreased frequency and intensity of the “island mass effect”. Decreased phytoplankton productivity at the PEI likely results from the southward shift in the average position of the sub-Antarctic Front (SAF), most likely in response to climate change, which in turn promotes flow-through conditions rather than retention at the PEI.
- Full Text:
- Date Issued: 2011
An experimental study of self-regulated learning with mildly gifted learners in grade 3 mathematics
- Authors: Allers, Amanda Lynette
- Date: 2019
- Subjects: Gifted children -- Education , Motivation in education Academic achievement Mathematics -- Study and teaching (Primary)
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: http://hdl.handle.net/10948/42074 , vital:36623
- Description: The study investigated whether self-regulated learning (SRL) strategies can be used successfully by Grade 3 mildly gifted learners (MGLs), in order to master an enriched advanced level mathematics curriculum. In accordance with internationally and nationally accepted principles, learners of diverse abilities should be given equal opportunities to achieve their full learning potential. The stark reality is that rigid application of the national curriculum currently used in South African primary schools, limits this ideal. MGLs possess skills that enable them to study at an increased level, a quicker pace and with an advanced degree of independence. The study employed the true experimental research. Sixty-four learners participated in the Mathematics Enrichment Programme. Purposive sampling was used to identify and select these learners. Subsequent to SRL pre-tests, simple random sampling was used to determine the experimental and control groups. The experimental group used problem-solving and 21st Century technology to develop SRL strategies. Direct teaching strategies were used for the control group. Learners were administered pre-tests, diagnostic problem-solving assessments, and post-tests relating to problem-solving and SRL. Chi-square tests and inferential t-tests were employed to draw comparisons within and between the groups regarding SRL and problem-solving scores. Univariate ANCOVAs were conducted to determine the post-test differences. Furthermore, Cronbach alpha was used to measure reliability of summated scores relating to SRL and problem-solving. The empirical results suggest that MGLs in Grade 3 are indeed capable of self-regulating their learning. This enhanced learners’ self-determination, self-confidence, self-motivation, self-independence, and self-empowerment in relation to their tasks. The empirical results suggest a significant constructive addition to the present standard curriculum for MGLs in the mainstream of education. The self-regulatory model for Foundation Phase MGLs which evolved from this study can be successfully employed to balance the diversity challenges in an inclusive education system. The findings of this study can have significant implications for future teacher training and education of MGLs in primary schools.
- Full Text:
- Date Issued: 2019
- Authors: Allers, Amanda Lynette
- Date: 2019
- Subjects: Gifted children -- Education , Motivation in education Academic achievement Mathematics -- Study and teaching (Primary)
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: http://hdl.handle.net/10948/42074 , vital:36623
- Description: The study investigated whether self-regulated learning (SRL) strategies can be used successfully by Grade 3 mildly gifted learners (MGLs), in order to master an enriched advanced level mathematics curriculum. In accordance with internationally and nationally accepted principles, learners of diverse abilities should be given equal opportunities to achieve their full learning potential. The stark reality is that rigid application of the national curriculum currently used in South African primary schools, limits this ideal. MGLs possess skills that enable them to study at an increased level, a quicker pace and with an advanced degree of independence. The study employed the true experimental research. Sixty-four learners participated in the Mathematics Enrichment Programme. Purposive sampling was used to identify and select these learners. Subsequent to SRL pre-tests, simple random sampling was used to determine the experimental and control groups. The experimental group used problem-solving and 21st Century technology to develop SRL strategies. Direct teaching strategies were used for the control group. Learners were administered pre-tests, diagnostic problem-solving assessments, and post-tests relating to problem-solving and SRL. Chi-square tests and inferential t-tests were employed to draw comparisons within and between the groups regarding SRL and problem-solving scores. Univariate ANCOVAs were conducted to determine the post-test differences. Furthermore, Cronbach alpha was used to measure reliability of summated scores relating to SRL and problem-solving. The empirical results suggest that MGLs in Grade 3 are indeed capable of self-regulating their learning. This enhanced learners’ self-determination, self-confidence, self-motivation, self-independence, and self-empowerment in relation to their tasks. The empirical results suggest a significant constructive addition to the present standard curriculum for MGLs in the mainstream of education. The self-regulatory model for Foundation Phase MGLs which evolved from this study can be successfully employed to balance the diversity challenges in an inclusive education system. The findings of this study can have significant implications for future teacher training and education of MGLs in primary schools.
- Full Text:
- Date Issued: 2019
Commercial maritime higher education needs in South Africa
- Authors: Allison, Lee-Ann
- Date: 2020
- Subjects: Marine resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/47496 , vital:40117
- Description: Seaborne cargo trade accounts for over 80% of the physical volume of global trade. Maritime transport thus fulfills an integral function in the economy of the world. South Africa generates approximately 3.5% of the world’s seaborne trade by value and 1.61% by tonnage, but the business of shipping all that cargo is undertaken by foreign firms. Operation Phakisa, the Comprehensive Maritime Transport Policy, and the South African Maritime Road Map, in pursuance of the National Development Plan, aim to revive the commercial maritime sector. In order to meet the demand for the skills and innovative abilities sought at executive and managerial levels in the commercial maritime sector, higher education in the knowledge of maritime business is increasingly becoming a prerequisite. Investment in higher education of quality and relevance in the maritime field would contribute to achieving the goals of the government for harnessing the potential of South Africa’s blue economy. The literature is researched in order to establish an authoritative view that the knowledge and the inspiration for entrepreneurial activity in the maritime sector can be imparted through higher education; and for example, that a viable shipping sector can contribute to the growth of a country’s economy. The South African maritime sector is then described. The commercial maritime higher education available at universities and other institutions of higher learning in South Africa, as well as in other African countries and elsewhere in the world, is examined, in order to be able to identify the degree and diploma courses available. Maritime courses imply not only the content of the educational material, but also the method whereby the knowledge is instilled in learners, and which extends well beyond the classroom. A survey, by way of the personal interviews of leaders in maritime business, maritime government affairs, and academics teaching maritime topics, is then undertaken to ascertain their views on the education required to promote the maritime sector in South Africa, using the list of subjects available for study worldwide, to assist their choice. The literature research and the interview survey by design also enable the secondary aims of the study to be achieved. Those aims include determining how awareness of the maritime domain could be raised and how co-operation between academia, business, and government, known as the triple helix could be organized, to promote the growth of the maritime sector. The results of the survey are analyzed and tabulated, in order to illustrate the extent of the agreement between those interviewed and the conclusions reached. These conclusions establish: (i) that the commercial maritime education currently available in South Africa, is inadequate to meet the aim of the government to the sector; (ii) that a post-graduate degree iv in the specified maritime studies incorporating a period of internship, and following on the first degree in business subjects, is required; (iii) that a triple helix of co-operation between academia, business, and the government is essential to grow the commercial maritime sector in which South African entrepreneurs educated in such business will have the advantage; (iv) that greater awareness of the maritime domain is essential in South Africa if entrepreneurship in maritime business is to be cultivated; and (v)that such awareness can be cultivated in various ways; but it should start by including more maritime topics in the current school curricula.
- Full Text:
- Date Issued: 2020
- Authors: Allison, Lee-Ann
- Date: 2020
- Subjects: Marine resources
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/47496 , vital:40117
- Description: Seaborne cargo trade accounts for over 80% of the physical volume of global trade. Maritime transport thus fulfills an integral function in the economy of the world. South Africa generates approximately 3.5% of the world’s seaborne trade by value and 1.61% by tonnage, but the business of shipping all that cargo is undertaken by foreign firms. Operation Phakisa, the Comprehensive Maritime Transport Policy, and the South African Maritime Road Map, in pursuance of the National Development Plan, aim to revive the commercial maritime sector. In order to meet the demand for the skills and innovative abilities sought at executive and managerial levels in the commercial maritime sector, higher education in the knowledge of maritime business is increasingly becoming a prerequisite. Investment in higher education of quality and relevance in the maritime field would contribute to achieving the goals of the government for harnessing the potential of South Africa’s blue economy. The literature is researched in order to establish an authoritative view that the knowledge and the inspiration for entrepreneurial activity in the maritime sector can be imparted through higher education; and for example, that a viable shipping sector can contribute to the growth of a country’s economy. The South African maritime sector is then described. The commercial maritime higher education available at universities and other institutions of higher learning in South Africa, as well as in other African countries and elsewhere in the world, is examined, in order to be able to identify the degree and diploma courses available. Maritime courses imply not only the content of the educational material, but also the method whereby the knowledge is instilled in learners, and which extends well beyond the classroom. A survey, by way of the personal interviews of leaders in maritime business, maritime government affairs, and academics teaching maritime topics, is then undertaken to ascertain their views on the education required to promote the maritime sector in South Africa, using the list of subjects available for study worldwide, to assist their choice. The literature research and the interview survey by design also enable the secondary aims of the study to be achieved. Those aims include determining how awareness of the maritime domain could be raised and how co-operation between academia, business, and government, known as the triple helix could be organized, to promote the growth of the maritime sector. The results of the survey are analyzed and tabulated, in order to illustrate the extent of the agreement between those interviewed and the conclusions reached. These conclusions establish: (i) that the commercial maritime education currently available in South Africa, is inadequate to meet the aim of the government to the sector; (ii) that a post-graduate degree iv in the specified maritime studies incorporating a period of internship, and following on the first degree in business subjects, is required; (iii) that a triple helix of co-operation between academia, business, and the government is essential to grow the commercial maritime sector in which South African entrepreneurs educated in such business will have the advantage; (iv) that greater awareness of the maritime domain is essential in South Africa if entrepreneurship in maritime business is to be cultivated; and (v)that such awareness can be cultivated in various ways; but it should start by including more maritime topics in the current school curricula.
- Full Text:
- Date Issued: 2020