A strategic analysis on the meaning of work: a focus on the fashion retail industry
- Authors: Van Heerden, Lisle
- Date: 2016
- Subjects: Retail trade -- South Africa Job satisfaction -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/13936 , vital:27360
- Description: The primary objective of this research study was to strategically analyse the meaning of work for fashion retail industry employees with the aim of developing a calling orientation to work.A sample of 84 fashion retail industry employees from Port Elizabeth, South Africa indicated their perception of callings in work; the pathways to callings in work and job satisfaction. Furthermore, fashion retail industry employees also indicated their use of job crafting techniques as a tool to foster meaningful work. This is one of the first studies conducted on callings in work in the fashion retail industry.Findings of the study indicated that although on average fashion retail industry employees are neutral about having a calling orientation to work, 24-27% indicated to having a calling orientation to work. Furthermore the study showed that there is a positive correlation between 1) transcendent guiding force; 2) value-driven behaviour and sense and meaning; 3) identification with one’s work and person-environment fit and a calling orientation to work. The study also indicated that the presence of a transcendent guiding force and job satisfaction are the two independent variables that are influential in achieving calling orientation to work for fashion retail industry employees of Port Elizabeth. Implications and recommendations from this study are outlined.
- Full Text:
- Date Issued: 2016
- Authors: Van Heerden, Lisle
- Date: 2016
- Subjects: Retail trade -- South Africa Job satisfaction -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/13936 , vital:27360
- Description: The primary objective of this research study was to strategically analyse the meaning of work for fashion retail industry employees with the aim of developing a calling orientation to work.A sample of 84 fashion retail industry employees from Port Elizabeth, South Africa indicated their perception of callings in work; the pathways to callings in work and job satisfaction. Furthermore, fashion retail industry employees also indicated their use of job crafting techniques as a tool to foster meaningful work. This is one of the first studies conducted on callings in work in the fashion retail industry.Findings of the study indicated that although on average fashion retail industry employees are neutral about having a calling orientation to work, 24-27% indicated to having a calling orientation to work. Furthermore the study showed that there is a positive correlation between 1) transcendent guiding force; 2) value-driven behaviour and sense and meaning; 3) identification with one’s work and person-environment fit and a calling orientation to work. The study also indicated that the presence of a transcendent guiding force and job satisfaction are the two independent variables that are influential in achieving calling orientation to work for fashion retail industry employees of Port Elizabeth. Implications and recommendations from this study are outlined.
- Full Text:
- Date Issued: 2016
A strategic analysis of Capitec Bank Limited within the South African banking industry
- Authors: De Lange, Michael Coenraad
- Date: 2013
- Subjects: Banks and banking -- South Africa , Creative ability in business -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8835 , http://hdl.handle.net/10948/d1019932
- Description: The South African banking industry is well regulated and oligopolistic by nature. The financial sector in South Africa is of a world class standard, comparing favourably to that of developed countries i.e. United States of America and Great Britian, and developing economies such as the BRIC (Brazil, Russia, India and China) countries. The South African financial sector possesses the critical elements to exhibit good growth and sustainable profitabiblity. Capitec Bank Limited revolutionised the banking industry by providing a simplified and cost effective banking solution targeting the masses i.e. the "unbanked" population of South Africa. The company pursued a disruptive innovation strategy by targeting the lower income earning segment of the market i.e. individuals who are employed but do not have bank account. Capite's strategic approach and business model were designed around innovation and technology, exploiting a previously untapped market that no other competitor targeted. This approach has resulted in the bank's phenomenal growth over the past decade and most notably has seen Capitec's return on equity (ROE) increase from 12 percent to 26 percent and advances to costomers increase from R116 million to 16 billion. This has set precedent which the big four banks, namely ABSA, First National Bank, Standard Bank and Nedbank, could not match. Contributing to Capitec's success and the basis on which its business model is built are four pillars: accessibilty, simplicity, affordability and personalised service. These pillars have created a compatitive advantage resulting in the bid four banks playing catch up. A strategic analysis of Capitec bank was conducted in order to assess the feasibility of expansion by the bank into Africa. The conclusion of the study indicated that it was indeed a viable option for Capitec to expand its footprint across borders into Africa through mergers with banks exhibiting a similar business model, for example Equity Bank based in Kenya.
- Full Text:
- Date Issued: 2013
- Authors: De Lange, Michael Coenraad
- Date: 2013
- Subjects: Banks and banking -- South Africa , Creative ability in business -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8835 , http://hdl.handle.net/10948/d1019932
- Description: The South African banking industry is well regulated and oligopolistic by nature. The financial sector in South Africa is of a world class standard, comparing favourably to that of developed countries i.e. United States of America and Great Britian, and developing economies such as the BRIC (Brazil, Russia, India and China) countries. The South African financial sector possesses the critical elements to exhibit good growth and sustainable profitabiblity. Capitec Bank Limited revolutionised the banking industry by providing a simplified and cost effective banking solution targeting the masses i.e. the "unbanked" population of South Africa. The company pursued a disruptive innovation strategy by targeting the lower income earning segment of the market i.e. individuals who are employed but do not have bank account. Capite's strategic approach and business model were designed around innovation and technology, exploiting a previously untapped market that no other competitor targeted. This approach has resulted in the bank's phenomenal growth over the past decade and most notably has seen Capitec's return on equity (ROE) increase from 12 percent to 26 percent and advances to costomers increase from R116 million to 16 billion. This has set precedent which the big four banks, namely ABSA, First National Bank, Standard Bank and Nedbank, could not match. Contributing to Capitec's success and the basis on which its business model is built are four pillars: accessibilty, simplicity, affordability and personalised service. These pillars have created a compatitive advantage resulting in the bid four banks playing catch up. A strategic analysis of Capitec bank was conducted in order to assess the feasibility of expansion by the bank into Africa. The conclusion of the study indicated that it was indeed a viable option for Capitec to expand its footprint across borders into Africa through mergers with banks exhibiting a similar business model, for example Equity Bank based in Kenya.
- Full Text:
- Date Issued: 2013
A strange counterpoint : classical music performance and identities in Grahamstown, South Africa
- Marais, Terence Wilmot Eugene
- Authors: Marais, Terence Wilmot Eugene
- Date: 2011
- Subjects: Music -- Western influences Music -- Performance -- Psychological aspects Music appreciation -- South Africa -- Grahamstown Music -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2677 , http://hdl.handle.net/10962/d1007491
- Description: This study investigates the perceptions of South African practitioners of Western European Art Music (WEAM), specifically as they relate to the value of WEAM in contemporary South African society. In exploring some of the connections between musical identity and national identity, it sets out to discover what value WEAM holds for a certain group of student pianists. Qualitative empirical data was collected in the form of in-depth, semi-structured interviews and questionnaire responses, and the findings point to numerous, nuanced expressions of self and varied intersections of the nation with musical identity in the life of the individual. Further, WEAM appears to represent a crucial point of identification for these individuals, in each case generating positive affirmations of the self.
- Full Text:
- Date Issued: 2011
- Authors: Marais, Terence Wilmot Eugene
- Date: 2011
- Subjects: Music -- Western influences Music -- Performance -- Psychological aspects Music appreciation -- South Africa -- Grahamstown Music -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2677 , http://hdl.handle.net/10962/d1007491
- Description: This study investigates the perceptions of South African practitioners of Western European Art Music (WEAM), specifically as they relate to the value of WEAM in contemporary South African society. In exploring some of the connections between musical identity and national identity, it sets out to discover what value WEAM holds for a certain group of student pianists. Qualitative empirical data was collected in the form of in-depth, semi-structured interviews and questionnaire responses, and the findings point to numerous, nuanced expressions of self and varied intersections of the nation with musical identity in the life of the individual. Further, WEAM appears to represent a crucial point of identification for these individuals, in each case generating positive affirmations of the self.
- Full Text:
- Date Issued: 2011
A step forward in defining Hsp90s as potential drug targets for human parasitic diseases
- Authors: Faya, Ngonidzashe
- Date: 2014
- Subjects: Heat shock proteins -- Research , Malaria -- Chemotherapy -- Research , Antimalarials -- Development -- Research , Parasitic diseases -- Research , Plasmodium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4110 , http://hdl.handle.net/10962/d1012993
- Description: Parasitic diseases remain a health burden affecting more than 500 million people worldwide with malaria having the highest mortality rate. The parasites can be transferred to the human bodies either through the mouth by ingestion of contaminated food and water or through the skin by bug bites or direct contact to environments harbouring them. Epidemiological control seems to be impossible since there is failure to control the insect vectors as well as practice of hygiene. Therefore, this has led to the development of a number of vaccines, chemotherapy and disease control programs. However, parasites have increasingly developed resistance to traditionally used anti-parasitic drugs and due to that fact there is need for alternative medication for parasitic diseases. Heat shock protein 90 (Hsp90) facilitates the folding of proteins in all living cells and their role is more important to parasites because of their environmental changes, from vector to host. Hsp90s play a major role; therefore this justifies the need for a deeper analysis of the parasitic Hsp90s. Recent studies have revealed that, the Plasmodium sp. Hsp90 has an extended linker region which increases the protein’s affinity for ATP and its inhibitors. Therefore we hypothesize that there are also significant features in other parasitic Hsp90s which would lead to Hsp90 being defined as potential drug targets. In the present study an attempt was made to gain more insight into the differences in primary structure of human and parasitic Hsp90s. The sequences were retrieved from the NCBI database and analysis was done in three groups basing on the localization of the Hsp90. The physicochemical properties were calculated and in every group, the protozoan Hsp90s showed significant differences when compared to the human orthologs. Multiple sequence alignments (MSA) showed that endoplasmic reticulum Hsp90s have an extended region in the middle domain indicating their ability to bind to a unique subset of client proteins. Sequence identities between the human and parasites showed that the protozoan Hsp90s are less related to the human Hsp90s as compared to the other parasites. Likewise, motif analysis showed the trypanosomatids and apicomplexan groups have their own unique set of motifs and they were grouped together in the phylogenetic analysis. Phylogenetic analysis also showed that, the protozoan Hsp90s forms their own clades in each group while the helminths did not form in endoplasmic reticulum group. In this study, we concluded that, Hsp90 can be a potential drug target for the protozoan species and more specifically those from the apicomplexan and trypanosomatids groups.
- Full Text:
- Date Issued: 2014
- Authors: Faya, Ngonidzashe
- Date: 2014
- Subjects: Heat shock proteins -- Research , Malaria -- Chemotherapy -- Research , Antimalarials -- Development -- Research , Parasitic diseases -- Research , Plasmodium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4110 , http://hdl.handle.net/10962/d1012993
- Description: Parasitic diseases remain a health burden affecting more than 500 million people worldwide with malaria having the highest mortality rate. The parasites can be transferred to the human bodies either through the mouth by ingestion of contaminated food and water or through the skin by bug bites or direct contact to environments harbouring them. Epidemiological control seems to be impossible since there is failure to control the insect vectors as well as practice of hygiene. Therefore, this has led to the development of a number of vaccines, chemotherapy and disease control programs. However, parasites have increasingly developed resistance to traditionally used anti-parasitic drugs and due to that fact there is need for alternative medication for parasitic diseases. Heat shock protein 90 (Hsp90) facilitates the folding of proteins in all living cells and their role is more important to parasites because of their environmental changes, from vector to host. Hsp90s play a major role; therefore this justifies the need for a deeper analysis of the parasitic Hsp90s. Recent studies have revealed that, the Plasmodium sp. Hsp90 has an extended linker region which increases the protein’s affinity for ATP and its inhibitors. Therefore we hypothesize that there are also significant features in other parasitic Hsp90s which would lead to Hsp90 being defined as potential drug targets. In the present study an attempt was made to gain more insight into the differences in primary structure of human and parasitic Hsp90s. The sequences were retrieved from the NCBI database and analysis was done in three groups basing on the localization of the Hsp90. The physicochemical properties were calculated and in every group, the protozoan Hsp90s showed significant differences when compared to the human orthologs. Multiple sequence alignments (MSA) showed that endoplasmic reticulum Hsp90s have an extended region in the middle domain indicating their ability to bind to a unique subset of client proteins. Sequence identities between the human and parasites showed that the protozoan Hsp90s are less related to the human Hsp90s as compared to the other parasites. Likewise, motif analysis showed the trypanosomatids and apicomplexan groups have their own unique set of motifs and they were grouped together in the phylogenetic analysis. Phylogenetic analysis also showed that, the protozoan Hsp90s forms their own clades in each group while the helminths did not form in endoplasmic reticulum group. In this study, we concluded that, Hsp90 can be a potential drug target for the protozoan species and more specifically those from the apicomplexan and trypanosomatids groups.
- Full Text:
- Date Issued: 2014
A status assessment of mangrove forests in South Africa and the utilization of mangroves at Mngazana Estuary
- Authors: Rajkaran, Anusha
- Date: 2011
- Subjects: Mangrove forests -- Management , Forests and forestry -- Harvesting , Mangrove forests -- South Africa -- Mngazana Estuary , Mangrove ecology -- South Africa -- Mngazana Estuary , Mangrove conservation
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10604 , http://hdl.handle.net/10948/1547 , Mangrove forests -- Management , Forests and forestry -- Harvesting , Mangrove forests -- South Africa -- Mngazana Estuary , Mangrove ecology -- South Africa -- Mngazana Estuary , Mangrove conservation
- Description: In South Africa mangrove forests are located in estuaries from Kosi Bay in KwaZulu-Natal (KZN) to Nahoon Estuary in the Eastern Cape. The aims of this study were to determine the present state of mangroves in KwaZulu-Natal, by assessing the current population structure, the changes in cover over time and associated anthropogenic pressures. A second objective of this study was to determine the effect of harvesting on the population structure and sediment characteristics in the Mngazana mangrove forest. To determine if harvesting was sustainable at Mngazana Estuary; the growth and mortality rates and associated growth conditions were measured. Finally by using population modelling sustainable harvesting limits were determined by predicting the change in population structure over time. The study focussed on the KwaZulu-Natal province as a fairly recent study addressed mangrove distribution and status in the Eastern Cape Province. A historical assessment of all mangroves forests in KwaZulu-Natal (KZN) revealed that the potential threats to mangroves in South Africa include; wood harvesting, altered water flow patterns coupled with salinity changes, prolonged closed-mouth conditions and subsequent changes to the intertidal habitat. As a result mangroves were completely lost from eleven estuaries in KZN between 1982 and 1999 and a further two estuaries by 2006. Mangroves only occurred in those estuaries where the mouth was open for more than 56 percent of the time with the exception of St Lucia, where the mouth has been closed for longer but the mangrove communities have persisted because the roots of the trees were not submerged. All mangrove forests in KZN were regenerating in terms of population structure as they had reverse J-shaped population curves as well as high adult: seedling ratios. Kosi Bay and Mhlathuze Estuary were two of the larger forests that showed signs of harvesting (presence of tree or branch stumps), but the greatest threat to smaller estuaries seems to be altered water flow patterns due to freshwater abstraction in the catchments and the change of land use from natural vegetation to sugar-cane plantations. These threats affect the hydrology of estuaries and the sediment characteristics (particle size, redox, pH, salinity, temperature) of the mangrove forests. The environmental conditions under which the mangrove forests currently exist were determined for five species. Lumnitzera racemosa and Ceriops tagal exhibited a narrow range of conditions as these species are only found at Kosi Bay, while Avicennia marina, Bruguiera gymnorrhiza and Rhizophora mucronata were found to exist under a wider range of conditions. The growth rate and response to environmental conditions of the three dominant species were important to determine as these species are impacted by harvesting. Mangrove growth rates were measured at Mngazana Estuary in the Eastern Cape, the third largest mangrove forest in South Africa. Areas of this estuary where mangroves harvesting has occurred, show significant differences in sediment characteristics as well as changes in population structure in harvested compared to non harvested sites. The growth rate (in terms of height) of Avicennia marina individuals increased from seedlings (0.31 cm month-1) to adults (1.2 cm month-1), while the growth of Bruguiera gymnorrhiza stabilised from a height of 150 cm at 0.65 cm month-1. The growth of Rhizophora mucronata peaked at 0.72 cm month-1 (height 151-250 cm) and then decreased to 0.4 cm month-1 for taller individuals. Increases in diameter at breast height (DBH) ranged between 0.7 and 2.3 mm month-1 for all species. Some environmental variables were found to be important drivers of growth and mortality of individuals less then 150 cm. A decrease in sediment pH significantly increased the mortality of Avicennia marina seedlings (0-50 cm) (r = - 0.71, p<0.05) and significantly decreased the growth of Rhizophora mucronata and Bruguiera gymnorrhiza seedlings (r = -0.8, r = 0.52 – p < 0.05 respectively). At Mngazana Estuary, mortality of this species showed a positive correlation with sediment moisture content indicating that this species prefers drier conditions. The density of Rhizophora mucronata was significantly correlated to porewater temperature in Northern KZN as was the growth of adult (>300 cm) Rhizophora trees at Mngazana Estuary. Mortality of Avicennia marina individuals (51-150 cm) was related to tree density indicating intraspecific competition and self thinning. Selective harvesting of particular size classes of Rhizophora mucronata was recorded when comparing length of harvested poles (~301 cm) and the size class distribution of individuals. Taking into account the differences in growth rate for each size class for this species it will take approximately 13 years to attain a height of 390 cm which is the height at which trees are selected for harvesting at this estuary. This is 2.6 times slower than those individuals growing in Kenya. The feasibility of harvesting is dependent on the growth rate of younger size classes to replace harvested trees as well as the rate of natural recruitment feeding into the population. Different harvesting intensity scenarios tested within a matrix model framework showed that limits should be set at 5 percent trees ha-1 year-1 to maintain seedling density at > 5 000 ha-1 for R. mucronata. However harvesting of Bruguiera gymnorrhiza should be stopped due to the low density of this species at Mngazana Estuary. Harvesting of the tallest trees of Avicennia marina can be maintained at levels less than 10 percent ha-1 year-1. Effective management of mangrove forests in South African is important to maintain the current state, function and diversity of these ecosystems. Management recommendations should begin with determining the freshwater requirements of the estuaries to maintain the mouth dynamics and biotic communities and deter the harvesting of (whole) adult trees particularly those species that do not coppice. Further management is needed to ensure that forests are cleared of pollutants (plastic and industrial), and any further developments near the mangroves should be minimized.
- Full Text:
- Date Issued: 2011
- Authors: Rajkaran, Anusha
- Date: 2011
- Subjects: Mangrove forests -- Management , Forests and forestry -- Harvesting , Mangrove forests -- South Africa -- Mngazana Estuary , Mangrove ecology -- South Africa -- Mngazana Estuary , Mangrove conservation
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10604 , http://hdl.handle.net/10948/1547 , Mangrove forests -- Management , Forests and forestry -- Harvesting , Mangrove forests -- South Africa -- Mngazana Estuary , Mangrove ecology -- South Africa -- Mngazana Estuary , Mangrove conservation
- Description: In South Africa mangrove forests are located in estuaries from Kosi Bay in KwaZulu-Natal (KZN) to Nahoon Estuary in the Eastern Cape. The aims of this study were to determine the present state of mangroves in KwaZulu-Natal, by assessing the current population structure, the changes in cover over time and associated anthropogenic pressures. A second objective of this study was to determine the effect of harvesting on the population structure and sediment characteristics in the Mngazana mangrove forest. To determine if harvesting was sustainable at Mngazana Estuary; the growth and mortality rates and associated growth conditions were measured. Finally by using population modelling sustainable harvesting limits were determined by predicting the change in population structure over time. The study focussed on the KwaZulu-Natal province as a fairly recent study addressed mangrove distribution and status in the Eastern Cape Province. A historical assessment of all mangroves forests in KwaZulu-Natal (KZN) revealed that the potential threats to mangroves in South Africa include; wood harvesting, altered water flow patterns coupled with salinity changes, prolonged closed-mouth conditions and subsequent changes to the intertidal habitat. As a result mangroves were completely lost from eleven estuaries in KZN between 1982 and 1999 and a further two estuaries by 2006. Mangroves only occurred in those estuaries where the mouth was open for more than 56 percent of the time with the exception of St Lucia, where the mouth has been closed for longer but the mangrove communities have persisted because the roots of the trees were not submerged. All mangrove forests in KZN were regenerating in terms of population structure as they had reverse J-shaped population curves as well as high adult: seedling ratios. Kosi Bay and Mhlathuze Estuary were two of the larger forests that showed signs of harvesting (presence of tree or branch stumps), but the greatest threat to smaller estuaries seems to be altered water flow patterns due to freshwater abstraction in the catchments and the change of land use from natural vegetation to sugar-cane plantations. These threats affect the hydrology of estuaries and the sediment characteristics (particle size, redox, pH, salinity, temperature) of the mangrove forests. The environmental conditions under which the mangrove forests currently exist were determined for five species. Lumnitzera racemosa and Ceriops tagal exhibited a narrow range of conditions as these species are only found at Kosi Bay, while Avicennia marina, Bruguiera gymnorrhiza and Rhizophora mucronata were found to exist under a wider range of conditions. The growth rate and response to environmental conditions of the three dominant species were important to determine as these species are impacted by harvesting. Mangrove growth rates were measured at Mngazana Estuary in the Eastern Cape, the third largest mangrove forest in South Africa. Areas of this estuary where mangroves harvesting has occurred, show significant differences in sediment characteristics as well as changes in population structure in harvested compared to non harvested sites. The growth rate (in terms of height) of Avicennia marina individuals increased from seedlings (0.31 cm month-1) to adults (1.2 cm month-1), while the growth of Bruguiera gymnorrhiza stabilised from a height of 150 cm at 0.65 cm month-1. The growth of Rhizophora mucronata peaked at 0.72 cm month-1 (height 151-250 cm) and then decreased to 0.4 cm month-1 for taller individuals. Increases in diameter at breast height (DBH) ranged between 0.7 and 2.3 mm month-1 for all species. Some environmental variables were found to be important drivers of growth and mortality of individuals less then 150 cm. A decrease in sediment pH significantly increased the mortality of Avicennia marina seedlings (0-50 cm) (r = - 0.71, p<0.05) and significantly decreased the growth of Rhizophora mucronata and Bruguiera gymnorrhiza seedlings (r = -0.8, r = 0.52 – p < 0.05 respectively). At Mngazana Estuary, mortality of this species showed a positive correlation with sediment moisture content indicating that this species prefers drier conditions. The density of Rhizophora mucronata was significantly correlated to porewater temperature in Northern KZN as was the growth of adult (>300 cm) Rhizophora trees at Mngazana Estuary. Mortality of Avicennia marina individuals (51-150 cm) was related to tree density indicating intraspecific competition and self thinning. Selective harvesting of particular size classes of Rhizophora mucronata was recorded when comparing length of harvested poles (~301 cm) and the size class distribution of individuals. Taking into account the differences in growth rate for each size class for this species it will take approximately 13 years to attain a height of 390 cm which is the height at which trees are selected for harvesting at this estuary. This is 2.6 times slower than those individuals growing in Kenya. The feasibility of harvesting is dependent on the growth rate of younger size classes to replace harvested trees as well as the rate of natural recruitment feeding into the population. Different harvesting intensity scenarios tested within a matrix model framework showed that limits should be set at 5 percent trees ha-1 year-1 to maintain seedling density at > 5 000 ha-1 for R. mucronata. However harvesting of Bruguiera gymnorrhiza should be stopped due to the low density of this species at Mngazana Estuary. Harvesting of the tallest trees of Avicennia marina can be maintained at levels less than 10 percent ha-1 year-1. Effective management of mangrove forests in South African is important to maintain the current state, function and diversity of these ecosystems. Management recommendations should begin with determining the freshwater requirements of the estuaries to maintain the mouth dynamics and biotic communities and deter the harvesting of (whole) adult trees particularly those species that do not coppice. Further management is needed to ensure that forests are cleared of pollutants (plastic and industrial), and any further developments near the mangroves should be minimized.
- Full Text:
- Date Issued: 2011
A statistical study of travelling ionospheric disturbances over the African-European and American sectors
- Authors: Thaganyana, Golekamang Piet
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/422541 , vital:71956 , DOI 10.21504/10962/422543
- Description: This research presents a long-term statistical study of travelling ionospheric disturbances (TIDs) of low- and high-latitude origin over the American and African-European sectors between 2010 and 2018. The TIDs of low latitude origin (hereafter known as poleward TIDs) were studied in both quiet and disturbed conditions, whereas the equatorward TIDs were only studied during quiet conditions. The Kp > 4 and Dst_ -50 nT was used as a criterion for geomagnetic disturbed conditions, while the four geomagnetically quiet days were selected each month based on Kp < 3. Observations of TIDs are made using Global Navigational Satellite Systems (GNSS) total electron content derived data. During quiet conditions, seven and two transhemispheric TIDs were identified over the African-European and American sectors, respectively. The observed TIDs originated from the wintertime hemisphere and propagated into the summertime hemisphere. The horizontal velocity, periods, and horizontal wavelengths of TIDs are in range of cH = 120-274 m/s, 48-80 min and _H = 379-1104 km, respectively. These quiet-time equatorward TIDs have been associated with tertiary gravity waves (GWs) from the dissipation of secondary GWs which are in turn generated from the dissipation of mountain waves (MWs) as a result of excited orographic forcing. The poleward TIDs during geomagnetically quiet conditions over the African and American sectors occur mainly during local daytime. Poleward TIDs were observed mostly in the African-European sector than the American sector. Their horizontal propagation velocities and periods range between 129-280 m/s and 39-70 min over African-European and American sectors. Although the mechanisms responsible for launching quiet-time poleward TIDs have not been established in this study, lower atmospheric processes such as convection systems, sudden stratospheric warming and cold weather fronts may have a role in their generation. During geomagnetic storms in the African sector, almost all poleward TIDs (with the exception of two cases) during the main phase were large-scale with horizontal velocities and periods ranging from 250-503 m/s and 30 min to 2 hours. During recovery phase, poleward TIDs fall under the category of medium scale. In the American sector, the majority of poleward TIDs occurred during the storm's main phase, as opposed to the African-European sector, which experienced a significant number of poleward TIDs during the recovery phase. The periods and horizontal velocities of TIDs range from 45 min-1.5 h and 180-296 m/s during main phase. During the recovery phase, the horizontal velocity and period range from 177-271 m/s and 40-1.5 h, respectively. Overall, it has been shown that statistically, changes in equatorial electrodynamics related to enhanced eastward electric _eld and hence increased equatorial electrojet (vertical E_B drift) correlates highly with the reported poleward TIDs. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2023
- Full Text:
- Date Issued: 2023-03-31
- Authors: Thaganyana, Golekamang Piet
- Date: 2023-03-31
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/422541 , vital:71956 , DOI 10.21504/10962/422543
- Description: This research presents a long-term statistical study of travelling ionospheric disturbances (TIDs) of low- and high-latitude origin over the American and African-European sectors between 2010 and 2018. The TIDs of low latitude origin (hereafter known as poleward TIDs) were studied in both quiet and disturbed conditions, whereas the equatorward TIDs were only studied during quiet conditions. The Kp > 4 and Dst_ -50 nT was used as a criterion for geomagnetic disturbed conditions, while the four geomagnetically quiet days were selected each month based on Kp < 3. Observations of TIDs are made using Global Navigational Satellite Systems (GNSS) total electron content derived data. During quiet conditions, seven and two transhemispheric TIDs were identified over the African-European and American sectors, respectively. The observed TIDs originated from the wintertime hemisphere and propagated into the summertime hemisphere. The horizontal velocity, periods, and horizontal wavelengths of TIDs are in range of cH = 120-274 m/s, 48-80 min and _H = 379-1104 km, respectively. These quiet-time equatorward TIDs have been associated with tertiary gravity waves (GWs) from the dissipation of secondary GWs which are in turn generated from the dissipation of mountain waves (MWs) as a result of excited orographic forcing. The poleward TIDs during geomagnetically quiet conditions over the African and American sectors occur mainly during local daytime. Poleward TIDs were observed mostly in the African-European sector than the American sector. Their horizontal propagation velocities and periods range between 129-280 m/s and 39-70 min over African-European and American sectors. Although the mechanisms responsible for launching quiet-time poleward TIDs have not been established in this study, lower atmospheric processes such as convection systems, sudden stratospheric warming and cold weather fronts may have a role in their generation. During geomagnetic storms in the African sector, almost all poleward TIDs (with the exception of two cases) during the main phase were large-scale with horizontal velocities and periods ranging from 250-503 m/s and 30 min to 2 hours. During recovery phase, poleward TIDs fall under the category of medium scale. In the American sector, the majority of poleward TIDs occurred during the storm's main phase, as opposed to the African-European sector, which experienced a significant number of poleward TIDs during the recovery phase. The periods and horizontal velocities of TIDs range from 45 min-1.5 h and 180-296 m/s during main phase. During the recovery phase, the horizontal velocity and period range from 177-271 m/s and 40-1.5 h, respectively. Overall, it has been shown that statistically, changes in equatorial electrodynamics related to enhanced eastward electric _eld and hence increased equatorial electrojet (vertical E_B drift) correlates highly with the reported poleward TIDs. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2023
- Full Text:
- Date Issued: 2023-03-31
A statistical study of the errors involved in the sampling and chemical analysis of soils and plants, with particular reference to citrus and pineapples
- Steyn, Willem Johannes Abraham
- Authors: Steyn, Willem Johannes Abraham
- Date: 1958
- Subjects: Soil chemistry , Plants -- Analysis , Soils -- Analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4506 , http://hdl.handle.net/10962/d1013291
- Description: 1. Accurate and reproducible methods for the determination of N and acid- extractable P in soils are described. The variations in N, P, and K found by intensive sampling of three different soil types are presented. 3. Suggestions for the adequate sampling of soils for various purposes arc given. 4. A study is presented of the preparative stages in leaf analysis (washing, drying, grinding and storage) as applied to citrus and pineapple leaf material. Likely errors are pointed out and procedures whereby these may be minimised are described. 5. A reliable wet-ashing procedure for obtaining leaf solutions is described. 6. Accurate and reproducible methods for the determination of total N, P,. K, Ca, Mg, Na, Fe, Mn, Zn and Cu in citrus and pineapple leaves are presented. 7. It is shown that diurnal variations in nutrient concentrations occur in citrus and pineapple leaves. 8. The variations in N, P, K, Ca, Mg, Na, Fe, Mn, Zn and Cu, occurring from tree to tree in 3 different Navel orange blocks are presented. It is shown that if all these elements are to be represented . to within 10% of the mean values on a 19 : 1 probability level, all the trees in the blocks would have to be sampled. Reasonable sampling procedures for various purposes are suggested. 9. The variations in N, P, K, Ca, Mg, Fe, Mn, Zn and Cu, occurring in 3 different Cayenne pineapple plantations are presented and described. Suitable sampling procedures are suggested.
- Full Text:
- Date Issued: 1958
- Authors: Steyn, Willem Johannes Abraham
- Date: 1958
- Subjects: Soil chemistry , Plants -- Analysis , Soils -- Analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4506 , http://hdl.handle.net/10962/d1013291
- Description: 1. Accurate and reproducible methods for the determination of N and acid- extractable P in soils are described. The variations in N, P, and K found by intensive sampling of three different soil types are presented. 3. Suggestions for the adequate sampling of soils for various purposes arc given. 4. A study is presented of the preparative stages in leaf analysis (washing, drying, grinding and storage) as applied to citrus and pineapple leaf material. Likely errors are pointed out and procedures whereby these may be minimised are described. 5. A reliable wet-ashing procedure for obtaining leaf solutions is described. 6. Accurate and reproducible methods for the determination of total N, P,. K, Ca, Mg, Na, Fe, Mn, Zn and Cu in citrus and pineapple leaves are presented. 7. It is shown that diurnal variations in nutrient concentrations occur in citrus and pineapple leaves. 8. The variations in N, P, K, Ca, Mg, Na, Fe, Mn, Zn and Cu, occurring from tree to tree in 3 different Navel orange blocks are presented. It is shown that if all these elements are to be represented . to within 10% of the mean values on a 19 : 1 probability level, all the trees in the blocks would have to be sampled. Reasonable sampling procedures for various purposes are suggested. 9. The variations in N, P, K, Ca, Mg, Fe, Mn, Zn and Cu, occurring in 3 different Cayenne pineapple plantations are presented and described. Suitable sampling procedures are suggested.
- Full Text:
- Date Issued: 1958
A statistical model for valuation of residential property in the Nelson Mandela Metropolitan area
- Authors: Van der Byl, Calven
- Date: 2012
- Subjects: Residential real estate -- Port Elizabeth , Housing -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9347 , http://hdl.handle.net/10948/d1020045
- Description: This study applies a process of correlation analysis and hedonic based modelling to investigate the influence of housing attributes and date of sale on transaction prices for residential real estate in the Nelson Mandela Metropole area. Availability of reliable data is a challenge in real estate studies in South Africa. This study integrates several publicly available resources for the purposes of constructing a statistical model. A model is constructed based on a forward variable selection routine using selection criteria. The resulting model shows six highly significant variables that can be used for modelling purposes. The resulting model is used to make comparisons in the value of the geographical location.
- Full Text:
- Date Issued: 2012
- Authors: Van der Byl, Calven
- Date: 2012
- Subjects: Residential real estate -- Port Elizabeth , Housing -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9347 , http://hdl.handle.net/10948/d1020045
- Description: This study applies a process of correlation analysis and hedonic based modelling to investigate the influence of housing attributes and date of sale on transaction prices for residential real estate in the Nelson Mandela Metropole area. Availability of reliable data is a challenge in real estate studies in South Africa. This study integrates several publicly available resources for the purposes of constructing a statistical model. A model is constructed based on a forward variable selection routine using selection criteria. The resulting model shows six highly significant variables that can be used for modelling purposes. The resulting model is used to make comparisons in the value of the geographical location.
- Full Text:
- Date Issued: 2012
A statistical evaluation and analysis of mosquito repellent combination
- Authors: Asquith, Ilse Bernadette
- Date: 2004
- Subjects: Mosquitoes -- Control , Insect baits and repellents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10422 , http://hdl.handle.net/10948/d1015732
- Description: The present product development project was aimed at studying the synergism and/or antagonism amongst various known insect repellent actives with the view to formulating a multi-active repellent product with improved properties when compared to current single-active commercial products. Advanced statistical methods were used to identify synergism between individual active substances and to define a formulation as close as possible to the “ideal” formulation. Several mosquito repellent samples were prepared and sent to the South African Bureau of Standards (SABS) in Pretoria to test for their efficiency in repelling mosquitoes. From the results of the repellency tests of the various active combinations, three actives were identified that showed promising signs of synergism. These actives were then studied in further detail to determine their optimum combination. In addition, it was shown that when using a natural flavourant as promoter and incorporating a slow-release agent into formulations for aerosols and lotions, a product is obtained that gives comparable levels of efficiency to current commercial products, but at much reduced levels of active loading. Accelerated stability tests performed on the final combination of the three actives used in the final formulation showed no adverse reactions over a three-week study. These tests shall be repeated once the final application form (lotion, aerosol, etc) and product packing have been decided.
- Full Text:
- Date Issued: 2004
- Authors: Asquith, Ilse Bernadette
- Date: 2004
- Subjects: Mosquitoes -- Control , Insect baits and repellents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10422 , http://hdl.handle.net/10948/d1015732
- Description: The present product development project was aimed at studying the synergism and/or antagonism amongst various known insect repellent actives with the view to formulating a multi-active repellent product with improved properties when compared to current single-active commercial products. Advanced statistical methods were used to identify synergism between individual active substances and to define a formulation as close as possible to the “ideal” formulation. Several mosquito repellent samples were prepared and sent to the South African Bureau of Standards (SABS) in Pretoria to test for their efficiency in repelling mosquitoes. From the results of the repellency tests of the various active combinations, three actives were identified that showed promising signs of synergism. These actives were then studied in further detail to determine their optimum combination. In addition, it was shown that when using a natural flavourant as promoter and incorporating a slow-release agent into formulations for aerosols and lotions, a product is obtained that gives comparable levels of efficiency to current commercial products, but at much reduced levels of active loading. Accelerated stability tests performed on the final combination of the three actives used in the final formulation showed no adverse reactions over a three-week study. These tests shall be repeated once the final application form (lotion, aerosol, etc) and product packing have been decided.
- Full Text:
- Date Issued: 2004
A Statistical assessment of available solar resource across multiple sites in South Africa
- Authors: Eastwood, Kirstie
- Date: 2019
- Subjects: Mathematical statistics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39907 , vital:35505
- Description: Around the globe, fossil fuels remain the primary source of energy at around 78% of the world’s total energy consumption. However, the associated carbon emissions, environmental impact, the depletion of fossil fuels and price and cost volatility are factors influencing the growing popularity of research into renewable energy. Solar power is acknowledged as the fastest-growing renewable energy, but the uncertainty surrounding the long-term projections of solar irradiance available for energy conversion is a hindrance when discussing the financial risk with potential investors. This study investigates the quality of freely available solar resource data in South Africa as well as proposes techniques for potential solar farm site comparisons. Tolerance intervals derived within a Bayesian framework provide information on the future available solar resource across multiple sites. These techniques capture the inherent variability in the available solar resource which equips investors with statistical methods that lead to the better understanding of the solar resource and thus aids in better decision-making.
- Full Text:
- Date Issued: 2019
- Authors: Eastwood, Kirstie
- Date: 2019
- Subjects: Mathematical statistics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39907 , vital:35505
- Description: Around the globe, fossil fuels remain the primary source of energy at around 78% of the world’s total energy consumption. However, the associated carbon emissions, environmental impact, the depletion of fossil fuels and price and cost volatility are factors influencing the growing popularity of research into renewable energy. Solar power is acknowledged as the fastest-growing renewable energy, but the uncertainty surrounding the long-term projections of solar irradiance available for energy conversion is a hindrance when discussing the financial risk with potential investors. This study investigates the quality of freely available solar resource data in South Africa as well as proposes techniques for potential solar farm site comparisons. Tolerance intervals derived within a Bayesian framework provide information on the future available solar resource across multiple sites. These techniques capture the inherent variability in the available solar resource which equips investors with statistical methods that lead to the better understanding of the solar resource and thus aids in better decision-making.
- Full Text:
- Date Issued: 2019
A STAT3 of addiction: adipose tissue, adipocytokine signalling and STAT3 as mediators of metabolic remodelling in the tumour microenvironment
- Kadye, Rose, Stoffels, Mihlali, Fanucci, Sidne, Mbanxa, Siso, Prinsloo, Earl
- Authors: Kadye, Rose , Stoffels, Mihlali , Fanucci, Sidne , Mbanxa, Siso , Prinsloo, Earl
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149395 , vital:38846 , https://doi.org/10.3390/cells9041043
- Description: Metabolic remodelling of the tumour microenvironment is a major mechanism by which cancer cells survive and resist treatment. The pro-oncogenic inflammatory cascade released by adipose tissue promotes oncogenic transformation, proliferation, angiogenesis, metastasis and evasion of apoptosis. STAT3 has emerged as an important mediator of metabolic remodelling. As a downstream effector of adipocytokines and cytokines, its canonical and non-canonical activities affect mitochondrial functioning and cancer metabolism. In this review, we examine the central role played by the crosstalk between the transcriptional and mitochondrial roles of STAT3 to promote survival and further oncogenesis within the tumour microenvironment with a particular focus on adipose-breast cancer interactions.
- Full Text:
- Date Issued: 2020
- Authors: Kadye, Rose , Stoffels, Mihlali , Fanucci, Sidne , Mbanxa, Siso , Prinsloo, Earl
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/149395 , vital:38846 , https://doi.org/10.3390/cells9041043
- Description: Metabolic remodelling of the tumour microenvironment is a major mechanism by which cancer cells survive and resist treatment. The pro-oncogenic inflammatory cascade released by adipose tissue promotes oncogenic transformation, proliferation, angiogenesis, metastasis and evasion of apoptosis. STAT3 has emerged as an important mediator of metabolic remodelling. As a downstream effector of adipocytokines and cytokines, its canonical and non-canonical activities affect mitochondrial functioning and cancer metabolism. In this review, we examine the central role played by the crosstalk between the transcriptional and mitochondrial roles of STAT3 to promote survival and further oncogenesis within the tumour microenvironment with a particular focus on adipose-breast cancer interactions.
- Full Text:
- Date Issued: 2020
A standards-based security model for health information systems
- Authors: Thomson, Steven Michael
- Date: 2008
- Subjects: Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Management information systems -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9786 , http://hdl.handle.net/10948/718 , Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Management information systems -- Security measures -- South Africa
- Description: In the healthcare environment, various types of patient information are stored in electronic format. This prevents the re-entering of information that was captured previously. In the past this information was stored on paper and kept in large filing cabinets. However, with the technology advancements that have occurred over the years, the idea of storing patient information in electronic systems arose. This led to a number of electronic health information systems being created, which in turn led to an increase in possible security risks. Any organization that stores information of a sensitive nature must apply information security principles in order to ensure that the stored information is kept secure. At a basic level, this entails ensuring the confidentiality, integrity and availability of the information, which is not an easy feat in today’s distributed and networked environments. This paved the way for organized standardization activities in the areas of information security and information security management. Throughout history, there have been practices that were created to help “standardize” industries of all areas, to the extent that there are professional organizations whose main objective it is to create such standards to help connect industries all over the world. This applies equally to the healthcare environment, where standardization took off in the late eighties. Healthcare organizations must follow standardized security measures to ensure that patient information stored in health information systems is kept secure. However, the proliferation in standards makes it difficult to understand, adopt and deploy these standards in a coherent manner. This research, therefore, proposes a standards-based security model for health information systems to ensure that such standards are applied in a manner that contributes to securing the healthcare environment as a whole, rather than in a piecemeal fashion.
- Full Text:
- Date Issued: 2008
- Authors: Thomson, Steven Michael
- Date: 2008
- Subjects: Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Management information systems -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9786 , http://hdl.handle.net/10948/718 , Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Management information systems -- Security measures -- South Africa
- Description: In the healthcare environment, various types of patient information are stored in electronic format. This prevents the re-entering of information that was captured previously. In the past this information was stored on paper and kept in large filing cabinets. However, with the technology advancements that have occurred over the years, the idea of storing patient information in electronic systems arose. This led to a number of electronic health information systems being created, which in turn led to an increase in possible security risks. Any organization that stores information of a sensitive nature must apply information security principles in order to ensure that the stored information is kept secure. At a basic level, this entails ensuring the confidentiality, integrity and availability of the information, which is not an easy feat in today’s distributed and networked environments. This paved the way for organized standardization activities in the areas of information security and information security management. Throughout history, there have been practices that were created to help “standardize” industries of all areas, to the extent that there are professional organizations whose main objective it is to create such standards to help connect industries all over the world. This applies equally to the healthcare environment, where standardization took off in the late eighties. Healthcare organizations must follow standardized security measures to ensure that patient information stored in health information systems is kept secure. However, the proliferation in standards makes it difficult to understand, adopt and deploy these standards in a coherent manner. This research, therefore, proposes a standards-based security model for health information systems to ensure that such standards are applied in a manner that contributes to securing the healthcare environment as a whole, rather than in a piecemeal fashion.
- Full Text:
- Date Issued: 2008
A standardised protocol for roadkill detection and the determinants of roadkill in the greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa
- Authors: Collinson, Wendy Jane
- Date: 2013
- Subjects: Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5606 , http://hdl.handle.net/10962/d1002056 , Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Description: Despite evidence suggesting that road traffic is a major threat to biodiversity loss, very little is known about its actual impact on wildlife populations in South Africa. Globally, road density and traffic volumes are increasing, and although huge budgets are devoted to the construction and upgrading of roads, there is little or no allocation to mitigation measures for protecting fauna in most countries, particularly Africa. Further, no global standardised protocol exists for the rapid assessment of roadkill or the most economical and efficient approach for assessing roadkill rates. Using vehicle field trials, the reliability of detecting artificially deployed roadkill was assessed. Roadkill detection rates decreased significantly at speeds >50 km/h and were also significantly influenced by light conditions (i.e. detection success was greater when the sun was high) and the position of the roadkill on the road (i.e. smaller roadkill on verges were often missed). These results suggest that roadkill sampling was most effective between 1.5 hours after dawn and 1.5 hours before dusk and that driving at slower speeds (<50 km.h⁻ₑ) was required to detect roadkill. This protocol was implemented across three ecological seasons on a 100 km paved road and a 20 km unpaved road in the Greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa. Driven daily over a 120-day period (three periods consisting each of 40 days), a total of 1,027 roadkill were recorded. These comprised 162 species from all terrestrial vertebrate groups with birds being the most commonly encountered roadkill (50% of all incidents). The high numbers of vertebrates identified as roadkill suggests that road traffic could have potentially unsustainable impacts on wildlife populations and hence the biodiversity of the area. Seventeen variables were identified as possible determinants of roadkill occurrence with season, rainfall, minimum and maximum temperature, habitat type, grass height, grass density, fence type and vehicle type significantly influencing roadkill numbers. Significantly more roadkill were detected on the paved road (9.91/100km) than on the unpaved road (1.8/100km) probably because of greater traffic volumes and the increased speed that vehicles travelled on the paved road. Warmer temperatures and increased rainfall in the preceding 24 hours also increased road mortality numbers as animals tended to become more active during these times. Interestingly, more roadkill was detected in open roadside habitats compared to dense roadside habitats on both the paved and unpaved roads and when grass on the roadside verge was of intermediate height. Open habitat possibly may provide a natural corridor for wildlife which ultimately end up on the road. Roadkill numbers increased when certain other physical barriers, such as cattle fences, were present, probably because these barriers were more penetrable than electric fencing. A series of mitigation measures are proposed to reduce the impacts of roads on wildlife in South Africa. These mitigation measures highlight the need to address the balance between the development of a country’s transport infrastructure and the conservation of its fauna. It is important that research on the impacts of roads becomes standardised to enable robust statistical comparisons which will provide a greater understanding of the potential threats to vertebrate biodiversity
- Full Text:
- Date Issued: 2013
- Authors: Collinson, Wendy Jane
- Date: 2013
- Subjects: Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5606 , http://hdl.handle.net/10962/d1002056 , Roadkill -- South Africa -- Mapungubwe Site , Traffic safety and wildlife -- South Africa -- Mapungubwe Site
- Description: Despite evidence suggesting that road traffic is a major threat to biodiversity loss, very little is known about its actual impact on wildlife populations in South Africa. Globally, road density and traffic volumes are increasing, and although huge budgets are devoted to the construction and upgrading of roads, there is little or no allocation to mitigation measures for protecting fauna in most countries, particularly Africa. Further, no global standardised protocol exists for the rapid assessment of roadkill or the most economical and efficient approach for assessing roadkill rates. Using vehicle field trials, the reliability of detecting artificially deployed roadkill was assessed. Roadkill detection rates decreased significantly at speeds >50 km/h and were also significantly influenced by light conditions (i.e. detection success was greater when the sun was high) and the position of the roadkill on the road (i.e. smaller roadkill on verges were often missed). These results suggest that roadkill sampling was most effective between 1.5 hours after dawn and 1.5 hours before dusk and that driving at slower speeds (<50 km.h⁻ₑ) was required to detect roadkill. This protocol was implemented across three ecological seasons on a 100 km paved road and a 20 km unpaved road in the Greater Mapungubwe Transfrontier Conservation Area, Limpopo Province, South Africa. Driven daily over a 120-day period (three periods consisting each of 40 days), a total of 1,027 roadkill were recorded. These comprised 162 species from all terrestrial vertebrate groups with birds being the most commonly encountered roadkill (50% of all incidents). The high numbers of vertebrates identified as roadkill suggests that road traffic could have potentially unsustainable impacts on wildlife populations and hence the biodiversity of the area. Seventeen variables were identified as possible determinants of roadkill occurrence with season, rainfall, minimum and maximum temperature, habitat type, grass height, grass density, fence type and vehicle type significantly influencing roadkill numbers. Significantly more roadkill were detected on the paved road (9.91/100km) than on the unpaved road (1.8/100km) probably because of greater traffic volumes and the increased speed that vehicles travelled on the paved road. Warmer temperatures and increased rainfall in the preceding 24 hours also increased road mortality numbers as animals tended to become more active during these times. Interestingly, more roadkill was detected in open roadside habitats compared to dense roadside habitats on both the paved and unpaved roads and when grass on the roadside verge was of intermediate height. Open habitat possibly may provide a natural corridor for wildlife which ultimately end up on the road. Roadkill numbers increased when certain other physical barriers, such as cattle fences, were present, probably because these barriers were more penetrable than electric fencing. A series of mitigation measures are proposed to reduce the impacts of roads on wildlife in South Africa. These mitigation measures highlight the need to address the balance between the development of a country’s transport infrastructure and the conservation of its fauna. It is important that research on the impacts of roads becomes standardised to enable robust statistical comparisons which will provide a greater understanding of the potential threats to vertebrate biodiversity
- Full Text:
- Date Issued: 2013
A standardisation of Professor Spearman’s “A measure of 'intelligence' for use in schools” and a discussion of the methods of factorial analysis as applied to the study of ability
- Authors: Butler, J E
- Date: 1949
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:20970 , http://hdl.handle.net/10962/5740
- Full Text:
- Date Issued: 1949
- Authors: Butler, J E
- Date: 1949
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:20970 , http://hdl.handle.net/10962/5740
- Full Text:
- Date Issued: 1949
A stakeholder framework for sustainable Supply chain management in the Zimbabwean food industry
- Authors: Munuhwa,Shakerod
- Date: 2022-12
- Subjects: Stakeholder , Supply chain management , Food industry -- Zimbabwe
- Language: English
- Type: Doctoral's theses , Thesis
- Identifier: http://hdl.handle.net/10948/60315 , vital:64397
- Description: The food supply chain plays an important role in the Zimbabwean food industry. More so sustainable food supply chain management (SFSCM) is a subject that has not received much attention, and yet it is so pertinent in determining food security in Zimbabwe. Zimbabwe has faced episodes of inadequate grain/cereal food reserves, hence the urgent need to develop a stakeholder framework for sustainable food supply chain management. The main objective of the study was to develop a stakeholder framework for SFSCM in the food industry. To accomplish the main objective, the research intended to achieve the following sub-objectives, namely to: establish the drivers for SFSCM; identify SFSCM practices within the food industry; identify the key stakeholders’ dynamic capabilities (SDCs) in the food industry and identify challenges faced by stakeholders in implementing SFSCM. The study also sought to establish the influence of: SFSCM drivers on implementing SFSCM practices; SFSCM drivers on SDCs; SFSCM practices on SDCs; SFSCM practices on SFSCM performance; SFSCM drivers on SFSCM performance; and SDCs on SFSCM performance. This study further sought to assess the mediation effect of: SFSCM drivers on the relationship between SFSCM practices and SDCs; SDCs on the relationship between SFSCM practices and SFSCM performance; SFSCM drivers on the relationship between SDCs and SFSCM performance and finally to assess the mediation effect of SDCs on the relationship between SFSCM drivers and SFSCM performance. This study employed a pragmatic philosophy that allowed for the collection of primary data using a fixed concurrent mixed methods (qualitative and quantitative) approach. The data analysis for this research included qualitative data from 22 participants and quantitative data from 292 respondents, all of whom were recruited through nine gatekeepers (Grain Marketing Board, Consumer Council of Zimbabwe, Food and Nutrition Association of Zimbabwe, Grain Millers Association of Zimbabwe, Ministry of Lands, Agriculture, Water and Rural Resettlement, Chartered Institute of Purchasing and Supply, Food and Agriculture Organization in Zimbabwe, Confederation of Zimbabwe Retailers and Zimbabwe National Chamber of Commerce). A thematic analysis was used to analyse qualitative data. For the quantitative data, the Statistical Package for the Social Sciences (SPSS) version 27 package was used to perform descriptive analysis, and principal component analysis for factor reduction and dimensional groups. Analysis of a Moment Structures (AMOS 26) program was used viii to perform structural equation modelling (SEM) for model fit evaluations and hypothesis tests. The mixed methods approach (both qualitative and quantitative) results identified regulatory pressure, market pressure, societal pressure, availability of resources, organisational culture and corporate objectives as some of the key SFSCM drivers. Additionally, the results identified the following as the key SFSCM practices: waste management, carbon emission reduction, logistics optimisation, water conservation, energy conservation, cost reduction and price efficiency, employment of competent people, cultivation of profitable grain crops, corporate social responsibility, fair distribution of food, human development on nutritious food consumption, food donations and continuously conducting consumer tastes surveys. Further, the mixed methods approach results cited the following key SDCs: sensing, seizing, reconfiguration, reflexive control, partner development, co-evolving and supply chain integration capabilities. Major challenges faced by stakeholders when implementing SFSCM were also identified and these involved lack of resources, lack of top management commitment, poor information sharing, lack of mutual trust amongst stakeholders, unmotivated employees, lack of government support, ever-changing food regulations, poor customer demand for sustainable and healthy foods, corruption and economic hardship challenges. The study also sought to establish relationships amongst variables. The mixed methods approach results revealed that SFSCM drivers have a positive influence on SFSCM practices, SDCs and SFSCM performance. The results also report a positive and significant influence of SFSCM practices on SDCs. The results further indicate that SDCs have a positive and significant influence on SFSCM performance. Although the qualitative findings reported a positive influence of SFSCM practices on SFSCM performance, the quantitative results from the SEM path analysis reported a very weak positive and insignificant influence of SFSCM practices on SFSCM performance. Mediation analysis was also performed using the quantitative data analysis only, and the results revealed that SFSCM drivers have significant partial mediation effect on the relationship between SFSCM practices and SDCs. The results also report that SDCs have a significant full mediation effect on the relationship between SFSCM practices and SFSCM performance. SFSCM drivers were found to have a significant ix partial mediation influence on the relationship between SDCs and SFSCM performance. Lastly, SDCs have a significant partial mediation effect on the relationship between SFSCM drivers and SFSCM performance. Based on the empirical results, conclusions were drawn, and recommendations were made. The research proposes a new stakeholder framework for SFSCM in the food industry. The study recommends that stakeholders consider providing training and education to all employees about the critical role of SFSCM in ensuring Zimbabwe's food security. Additionally, policymakers are urged to implement supply chain anticorruption and fair-trading policies in order to boost SFSCM performance. Stakeholder institutions are also urged to reward internal stakeholders who perform exceptionally well in terms of SFSCM in order to positively motivate all staff, and ultimately improve SFSCM. , Thesis (PHD) -- Faculty of Business and Economic Sciences, Business School, 2022
- Full Text:
- Date Issued: 2022-12
- Authors: Munuhwa,Shakerod
- Date: 2022-12
- Subjects: Stakeholder , Supply chain management , Food industry -- Zimbabwe
- Language: English
- Type: Doctoral's theses , Thesis
- Identifier: http://hdl.handle.net/10948/60315 , vital:64397
- Description: The food supply chain plays an important role in the Zimbabwean food industry. More so sustainable food supply chain management (SFSCM) is a subject that has not received much attention, and yet it is so pertinent in determining food security in Zimbabwe. Zimbabwe has faced episodes of inadequate grain/cereal food reserves, hence the urgent need to develop a stakeholder framework for sustainable food supply chain management. The main objective of the study was to develop a stakeholder framework for SFSCM in the food industry. To accomplish the main objective, the research intended to achieve the following sub-objectives, namely to: establish the drivers for SFSCM; identify SFSCM practices within the food industry; identify the key stakeholders’ dynamic capabilities (SDCs) in the food industry and identify challenges faced by stakeholders in implementing SFSCM. The study also sought to establish the influence of: SFSCM drivers on implementing SFSCM practices; SFSCM drivers on SDCs; SFSCM practices on SDCs; SFSCM practices on SFSCM performance; SFSCM drivers on SFSCM performance; and SDCs on SFSCM performance. This study further sought to assess the mediation effect of: SFSCM drivers on the relationship between SFSCM practices and SDCs; SDCs on the relationship between SFSCM practices and SFSCM performance; SFSCM drivers on the relationship between SDCs and SFSCM performance and finally to assess the mediation effect of SDCs on the relationship between SFSCM drivers and SFSCM performance. This study employed a pragmatic philosophy that allowed for the collection of primary data using a fixed concurrent mixed methods (qualitative and quantitative) approach. The data analysis for this research included qualitative data from 22 participants and quantitative data from 292 respondents, all of whom were recruited through nine gatekeepers (Grain Marketing Board, Consumer Council of Zimbabwe, Food and Nutrition Association of Zimbabwe, Grain Millers Association of Zimbabwe, Ministry of Lands, Agriculture, Water and Rural Resettlement, Chartered Institute of Purchasing and Supply, Food and Agriculture Organization in Zimbabwe, Confederation of Zimbabwe Retailers and Zimbabwe National Chamber of Commerce). A thematic analysis was used to analyse qualitative data. For the quantitative data, the Statistical Package for the Social Sciences (SPSS) version 27 package was used to perform descriptive analysis, and principal component analysis for factor reduction and dimensional groups. Analysis of a Moment Structures (AMOS 26) program was used viii to perform structural equation modelling (SEM) for model fit evaluations and hypothesis tests. The mixed methods approach (both qualitative and quantitative) results identified regulatory pressure, market pressure, societal pressure, availability of resources, organisational culture and corporate objectives as some of the key SFSCM drivers. Additionally, the results identified the following as the key SFSCM practices: waste management, carbon emission reduction, logistics optimisation, water conservation, energy conservation, cost reduction and price efficiency, employment of competent people, cultivation of profitable grain crops, corporate social responsibility, fair distribution of food, human development on nutritious food consumption, food donations and continuously conducting consumer tastes surveys. Further, the mixed methods approach results cited the following key SDCs: sensing, seizing, reconfiguration, reflexive control, partner development, co-evolving and supply chain integration capabilities. Major challenges faced by stakeholders when implementing SFSCM were also identified and these involved lack of resources, lack of top management commitment, poor information sharing, lack of mutual trust amongst stakeholders, unmotivated employees, lack of government support, ever-changing food regulations, poor customer demand for sustainable and healthy foods, corruption and economic hardship challenges. The study also sought to establish relationships amongst variables. The mixed methods approach results revealed that SFSCM drivers have a positive influence on SFSCM practices, SDCs and SFSCM performance. The results also report a positive and significant influence of SFSCM practices on SDCs. The results further indicate that SDCs have a positive and significant influence on SFSCM performance. Although the qualitative findings reported a positive influence of SFSCM practices on SFSCM performance, the quantitative results from the SEM path analysis reported a very weak positive and insignificant influence of SFSCM practices on SFSCM performance. Mediation analysis was also performed using the quantitative data analysis only, and the results revealed that SFSCM drivers have significant partial mediation effect on the relationship between SFSCM practices and SDCs. The results also report that SDCs have a significant full mediation effect on the relationship between SFSCM practices and SFSCM performance. SFSCM drivers were found to have a significant ix partial mediation influence on the relationship between SDCs and SFSCM performance. Lastly, SDCs have a significant partial mediation effect on the relationship between SFSCM drivers and SFSCM performance. Based on the empirical results, conclusions were drawn, and recommendations were made. The research proposes a new stakeholder framework for SFSCM in the food industry. The study recommends that stakeholders consider providing training and education to all employees about the critical role of SFSCM in ensuring Zimbabwe's food security. Additionally, policymakers are urged to implement supply chain anticorruption and fair-trading policies in order to boost SFSCM performance. Stakeholder institutions are also urged to reward internal stakeholders who perform exceptionally well in terms of SFSCM in order to positively motivate all staff, and ultimately improve SFSCM. , Thesis (PHD) -- Faculty of Business and Economic Sciences, Business School, 2022
- Full Text:
- Date Issued: 2022-12
A stable isotope approach to trophic ecology resolving food webs in intertidal ecosystems
- Authors: Hill, Jaclyn Marie
- Date: 2008
- Subjects: Stable isotopes Food chains (Ecology) Stable isotopes in ecological research Intertidal ecology Mussels -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5771 , http://hdl.handle.net/10962/d1005459
- Description: There are broad differences in regional oceanography and primary production around the South African coast, which we might expect to give rise to major differences in trophic pathways. δ⁻¹³C and δ⁻¹⁵N isotopic ratios of suspended particulate matter (SPM), mussels, various intertidal consumers and common macroalgae along the South African coastline were explored using stable isotope analysis to investigate biogeographic and temporal variability of isotopic signatures of marine intertidal consumers and their food sources around the coast of South Africa, with a focus on evaluating the dependence of intertidal mussels on phytoplankton and macroalgal-derived organic carbon. Isotopic equilibration rates of four mussel tissues were determined through laboratory feeding experiments, which established that adductor tissue had the slowest isotopic turnover rate, and was subsequently used as an indication of overall mussel diet. Biogeographic, temporal and nearshore/offshore trends of isotopic ratios of SPM were investigated along 10km transects perpendicular to the coast and SPM exhibited overall trends of carbon depletion when moving from west to east along the coastline and from nearshore to offshore water, in both cases suggesting a shift from macrophyte detritus to a phytoplankton signature. δ⁻¹³C signatures of SPM also revealed temporal and biogeographic variation that had strong ties to local oceanography, being closely correlated to regional hydrographic features and tidal influences. Mixing models indicated filter feeders demonstrated over 50% dependence on nearshore SPM for organic carbon and it was possible to categorize them into geographic groups based on their carbon and nitrogen signatures, suggesting biogeographic shifts in resources. Biogeographic shifts in diet were also seen in some grazers. Difficulties in relating macroalgae to mussel diet led to investigations into the isotopic changes associated with macroalgal decomposition. Variation in photosynthetic fractionation, leaching and microbial mineralization are believed to have resulted from species-specific patterns of degradation. Although the strong links between carbon signatures and local oceanography indicate that stable isotope analysis is a powerful tool for the study of water mixing and coastal hydrography in relation to food-web analyses, substantial variation in fractionation of primary consumers, along with different periods of time integration between consumers and their food sources must be considered in future studies, to resolve trophic links in marine food webs successfully.
- Full Text:
- Date Issued: 2008
- Authors: Hill, Jaclyn Marie
- Date: 2008
- Subjects: Stable isotopes Food chains (Ecology) Stable isotopes in ecological research Intertidal ecology Mussels -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5771 , http://hdl.handle.net/10962/d1005459
- Description: There are broad differences in regional oceanography and primary production around the South African coast, which we might expect to give rise to major differences in trophic pathways. δ⁻¹³C and δ⁻¹⁵N isotopic ratios of suspended particulate matter (SPM), mussels, various intertidal consumers and common macroalgae along the South African coastline were explored using stable isotope analysis to investigate biogeographic and temporal variability of isotopic signatures of marine intertidal consumers and their food sources around the coast of South Africa, with a focus on evaluating the dependence of intertidal mussels on phytoplankton and macroalgal-derived organic carbon. Isotopic equilibration rates of four mussel tissues were determined through laboratory feeding experiments, which established that adductor tissue had the slowest isotopic turnover rate, and was subsequently used as an indication of overall mussel diet. Biogeographic, temporal and nearshore/offshore trends of isotopic ratios of SPM were investigated along 10km transects perpendicular to the coast and SPM exhibited overall trends of carbon depletion when moving from west to east along the coastline and from nearshore to offshore water, in both cases suggesting a shift from macrophyte detritus to a phytoplankton signature. δ⁻¹³C signatures of SPM also revealed temporal and biogeographic variation that had strong ties to local oceanography, being closely correlated to regional hydrographic features and tidal influences. Mixing models indicated filter feeders demonstrated over 50% dependence on nearshore SPM for organic carbon and it was possible to categorize them into geographic groups based on their carbon and nitrogen signatures, suggesting biogeographic shifts in resources. Biogeographic shifts in diet were also seen in some grazers. Difficulties in relating macroalgae to mussel diet led to investigations into the isotopic changes associated with macroalgal decomposition. Variation in photosynthetic fractionation, leaching and microbial mineralization are believed to have resulted from species-specific patterns of degradation. Although the strong links between carbon signatures and local oceanography indicate that stable isotope analysis is a powerful tool for the study of water mixing and coastal hydrography in relation to food-web analyses, substantial variation in fractionation of primary consumers, along with different periods of time integration between consumers and their food sources must be considered in future studies, to resolve trophic links in marine food webs successfully.
- Full Text:
- Date Issued: 2008
A stability-indicating liquid chromatographic method for the analysis of erythromycin in stored biological fluids using amperometric detection
- Stubbs, Christopher, Haigh, John M, Kanfer, Isadore
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1987
- Language: English
- Type: Article
- Identifier: vital:6430 , http://hdl.handle.net/10962/d1006592
- Description: A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. This method allows both erythromycin and its principle degradation product, anhydroeythromycin, to be determined during a period of sample storage at 4 degree C and minus 15 degree C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.
- Full Text:
- Date Issued: 1987
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1987
- Language: English
- Type: Article
- Identifier: vital:6430 , http://hdl.handle.net/10962/d1006592
- Description: A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. This method allows both erythromycin and its principle degradation product, anhydroeythromycin, to be determined during a period of sample storage at 4 degree C and minus 15 degree C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.
- Full Text:
- Date Issued: 1987
A stability-indicating HPLC assay with on-line clean-up for betamethasone 17-valerate in topical dosage forms
- Smith, Eric W, Haigh, John M, Kanfer, Isadore
- Authors: Smith, Eric W , Haigh, John M , Kanfer, Isadore
- Date: 1985
- Language: English
- Type: Article
- Identifier: vital:6421 , http://hdl.handle.net/10962/d1006556
- Description: A stability-indicating high-performance liquid chromatographic method with on-line clean-up has been developed for the analysis of betamethasone 17-valerate in topical dosage forms. A short pre-column containing 10 μm octadecylsilane mounted into the sample loop position of an injection valve was used as the primary clean-up step. The utilization of a diode-array UV detector allowed the quantitative analysis of betamethasone 17-valerate together with its degradation product, betamethasone 21-valerate, as well as the qualitative analysis of these compounds, relevant internal standards and the preservatives chlorocresol and methyl hydroxybenzoate contained in the cream and lotion formulations, respectively. Typically, cream and lotion dosage forms were dissolved in acetonitrile and ointments in tetrahydrofuran, internal standards added and aliquots injected onto the analytical system. Dosage form excipients were retained on the loop column and back-flushed to waste with the aid of a second solvent pump while components of interest were allowed to transfer to the analytical column for quantitative analysis. The method is accurate, precise and stability indicating and permits the rapid on-line analysis of betamethasone 17-valerate from complex topical formulation matrices without prior extractions.
- Full Text:
- Date Issued: 1985
- Authors: Smith, Eric W , Haigh, John M , Kanfer, Isadore
- Date: 1985
- Language: English
- Type: Article
- Identifier: vital:6421 , http://hdl.handle.net/10962/d1006556
- Description: A stability-indicating high-performance liquid chromatographic method with on-line clean-up has been developed for the analysis of betamethasone 17-valerate in topical dosage forms. A short pre-column containing 10 μm octadecylsilane mounted into the sample loop position of an injection valve was used as the primary clean-up step. The utilization of a diode-array UV detector allowed the quantitative analysis of betamethasone 17-valerate together with its degradation product, betamethasone 21-valerate, as well as the qualitative analysis of these compounds, relevant internal standards and the preservatives chlorocresol and methyl hydroxybenzoate contained in the cream and lotion formulations, respectively. Typically, cream and lotion dosage forms were dissolved in acetonitrile and ointments in tetrahydrofuran, internal standards added and aliquots injected onto the analytical system. Dosage form excipients were retained on the loop column and back-flushed to waste with the aid of a second solvent pump while components of interest were allowed to transfer to the analytical column for quantitative analysis. The method is accurate, precise and stability indicating and permits the rapid on-line analysis of betamethasone 17-valerate from complex topical formulation matrices without prior extractions.
- Full Text:
- Date Issued: 1985
A stability-indicating high performance liquid chromatographic assay for the determination of orlistat in capsules
- Mohammadi, Ali, Haririan, I, Rezanour, Nasrin, Ghiasi, L, Walker, Roderick B
- Authors: Mohammadi, Ali , Haririan, I , Rezanour, Nasrin , Ghiasi, L , Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184267 , vital:44195 , xlink:href="https://doi.org/10.1016/j.chroma.2006.03.038"
- Description: A stability-indicating HPLC method was developed and validated for the quantitative determination of orlistat in capsule dosage forms. An isocratic separation was achieved using a Perfectsil® target ODS-3, 250 mm × 4.6 mm i.d., 5 μm particle size column with a flow rate of 0.7 ml/min and using a UV detector to monitor the eluate at 210 nm. The mobile phase consisted of methanol:acetonitrile:trifluoroacetic acid (82.5:17.5:0.01, v/v/v). The drug was subjected oxidation, hydrolysis, photolysis and heat to apply stress conditions. Complete separation was achieved for the parent compound and all degradation products in an overall analytical run time of approximately 15 min with the parent compound orlistat eluting at approximately 9 min. The method was linear over the concentration range of 0.02–0.75 mg/ml (r = 0.9998) with a limit of detection and quantitation 0.006 and 0.02 mg/ml, respectively. The method has the requisite accuracy, selectivity, sensitivity and precision to assay orlistat in capsules. Degradation products resulting from the stress studies did not interfere with the detection of orlistat and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2006
- Authors: Mohammadi, Ali , Haririan, I , Rezanour, Nasrin , Ghiasi, L , Walker, Roderick B
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184267 , vital:44195 , xlink:href="https://doi.org/10.1016/j.chroma.2006.03.038"
- Description: A stability-indicating HPLC method was developed and validated for the quantitative determination of orlistat in capsule dosage forms. An isocratic separation was achieved using a Perfectsil® target ODS-3, 250 mm × 4.6 mm i.d., 5 μm particle size column with a flow rate of 0.7 ml/min and using a UV detector to monitor the eluate at 210 nm. The mobile phase consisted of methanol:acetonitrile:trifluoroacetic acid (82.5:17.5:0.01, v/v/v). The drug was subjected oxidation, hydrolysis, photolysis and heat to apply stress conditions. Complete separation was achieved for the parent compound and all degradation products in an overall analytical run time of approximately 15 min with the parent compound orlistat eluting at approximately 9 min. The method was linear over the concentration range of 0.02–0.75 mg/ml (r = 0.9998) with a limit of detection and quantitation 0.006 and 0.02 mg/ml, respectively. The method has the requisite accuracy, selectivity, sensitivity and precision to assay orlistat in capsules. Degradation products resulting from the stress studies did not interfere with the detection of orlistat and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2006
A stability-indicating high performance liquid chromatographic assay for the determination of orlistat in capsules
- Mohammadi, Ali, Haririan, I, Rezanour, I, Ghiasi, L, Walker, Roderick B
- Authors: Mohammadi, Ali , Haririan, I , Rezanour, I , Ghiasi, L , Walker, Roderick B
- Date: 2006
- Language: English
- Type: Article , text
- Identifier: vital:6407 , http://hdl.handle.net/10962/d1006480
- Description: A stability-indicating HPLC method was developed and validated for the quantitative determination of orlistat in capsule dosage forms. An isocratic separation was achieved using a Perfectsil® target ODS-3, 250 mm × 4.6 mm i.d., 5 µm particle size column with a flow rate of 0.7 ml/min and using a UV detector to monitor the eluate at 210 nm. The mobile phase consisted of methanol:acetonitrile:trifluoroacetic acid (82.5:17.5:0.01, v/v/v). The drug was subjected oxidation, hydrolysis, photolysis and heat to apply stress conditions. Complete separation was achieved for the parent compound and all degradation products in an overall analytical run time of approximately 15 min with the parent compound orlistat eluting at approximately 9 min. The method was linear over the concentration range of 0.02–0.75 mg/ml (r = 0.9998) with a limit of detection and quantitation 0.006 and 0.02 mg/ml, respectively. The method has the requisite accuracy, selectivity, sensitivity and precision to assay orlistat in capsules. Degradation products resulting from the stress studies did not interfere with the detection of orlistat and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2006
- Authors: Mohammadi, Ali , Haririan, I , Rezanour, I , Ghiasi, L , Walker, Roderick B
- Date: 2006
- Language: English
- Type: Article , text
- Identifier: vital:6407 , http://hdl.handle.net/10962/d1006480
- Description: A stability-indicating HPLC method was developed and validated for the quantitative determination of orlistat in capsule dosage forms. An isocratic separation was achieved using a Perfectsil® target ODS-3, 250 mm × 4.6 mm i.d., 5 µm particle size column with a flow rate of 0.7 ml/min and using a UV detector to monitor the eluate at 210 nm. The mobile phase consisted of methanol:acetonitrile:trifluoroacetic acid (82.5:17.5:0.01, v/v/v). The drug was subjected oxidation, hydrolysis, photolysis and heat to apply stress conditions. Complete separation was achieved for the parent compound and all degradation products in an overall analytical run time of approximately 15 min with the parent compound orlistat eluting at approximately 9 min. The method was linear over the concentration range of 0.02–0.75 mg/ml (r = 0.9998) with a limit of detection and quantitation 0.006 and 0.02 mg/ml, respectively. The method has the requisite accuracy, selectivity, sensitivity and precision to assay orlistat in capsules. Degradation products resulting from the stress studies did not interfere with the detection of orlistat and the assay is thus stability-indicating.
- Full Text:
- Date Issued: 2006