Phytoplankton of the Southern Agulhas Large Marine Ecosystem (sACLME)
- Authors: Sonnekus, Martinus Jakobus
- Date: 2020
- Subjects: Botanical chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/47646 , vital:40261
- Description: The southern Agulhas Large Marine Ecosystem (sACLME) consists of the greater Agulhas Current system, including the areas influenced by the Agulhas Current, the Agulhas Shelf, Agulhas Bank, Agulhas Retroflection as well as the Agulhas Return Current. Four biogeographical regions were identified within the sACLME and the composition of the phytoplankton communities and the associated physico-chemical variables in each were investigated. Water temperature and nitrate concentration were found to be the main drivers of the sACLME phytoplankton community. A total of 215 phytoplankton taxa were identified that were separated into two groups: the Agulhas Current group and the Southwest Indian Ocean Ridge group. The structure of the phytoplankton community was consistently homogeneous throughout the sACLME. Nutrient concentrations of the water varied, but nitrate was the most abundant source of nitrogen, especially in regions that were subjected to the upwelling of cold nutrient-rich water. The phytoplankton communities were significantly influenced by the availability and stoichiometry of the macronutrients nitrogen; phosphorus and silicon. The low mean N:P ratio of 5.5 is an indication that the waters of the sACLME are generally nitrogen limited, as is typical of oceanic systems. There is a change in phytoplankton cell size and functional groups within in the various water masses that are specific to certain biogeographical regions within the Agulhas Current system. It is clear that frontal systems may form barriers between phytoplankton communities.
- Full Text:
- Date Issued: 2020
- Authors: Sonnekus, Martinus Jakobus
- Date: 2020
- Subjects: Botanical chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/47646 , vital:40261
- Description: The southern Agulhas Large Marine Ecosystem (sACLME) consists of the greater Agulhas Current system, including the areas influenced by the Agulhas Current, the Agulhas Shelf, Agulhas Bank, Agulhas Retroflection as well as the Agulhas Return Current. Four biogeographical regions were identified within the sACLME and the composition of the phytoplankton communities and the associated physico-chemical variables in each were investigated. Water temperature and nitrate concentration were found to be the main drivers of the sACLME phytoplankton community. A total of 215 phytoplankton taxa were identified that were separated into two groups: the Agulhas Current group and the Southwest Indian Ocean Ridge group. The structure of the phytoplankton community was consistently homogeneous throughout the sACLME. Nutrient concentrations of the water varied, but nitrate was the most abundant source of nitrogen, especially in regions that were subjected to the upwelling of cold nutrient-rich water. The phytoplankton communities were significantly influenced by the availability and stoichiometry of the macronutrients nitrogen; phosphorus and silicon. The low mean N:P ratio of 5.5 is an indication that the waters of the sACLME are generally nitrogen limited, as is typical of oceanic systems. There is a change in phytoplankton cell size and functional groups within in the various water masses that are specific to certain biogeographical regions within the Agulhas Current system. It is clear that frontal systems may form barriers between phytoplankton communities.
- Full Text:
- Date Issued: 2020
Determinants of Type 2 diabetes mellitus among HIV/AIDS patients on antiretroviral drugs in the OR Tambo District, South Africa
- Authors: Bam, Nokwanda Edith
- Date: 2018
- Subjects: HIV/AIDS Diabetes mellitus (DM) -- Patients Antiretroviral drugs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD Health Sciences
- Identifier: http://hdl.handle.net/11260/1476 , vital:35976
- Description: Type 2 diabetes mellitus (DM) is a frequent adverse effect of antiretroviral drugs for those who are on ARVS. People with type 2 DM can suffer multiple complications that hinder the quality of life. In South Africa research has shown significant increase in neuropathy, heart and kidney diseases among patients living with type 2 DM and HIV/AIDS compared to DM without HIV. Accessed knowledge lacked consistency on the predictors of DM in HIV/AIDS patients with regards to the type of ARVS with higher risks of DM. Research needed to be done to find the determinants of type 2 DM in HIV/AIDS context. The purpose of this study was to describe the determinants of type 2 DM among HIV/AIDS patients on ARVS in the OR Tambo District, SA in order to develop intervention strategies to mitigate the long-term effects of type 2 DM. A quantitative research methodology using a case control retrospective study was used. A sample of 177 (33%) cases with HIV/AIDS and type 2 DM was selected using a one stage stratified sampling with allocation proportional to size of each stratum of the four sub-districts of OR Tambo District. Two non-diabetic patients with HIV/AIDS were selected as controls per case unpaired and totalled up to 354 (67%) controls. A self-administration questionnaire adopted from the WHO (2011) STEPwise surveillance tool for chronic diseases was used for data collection. Stata (standard version 13.0, Stata Corp., Lakeway Drive USA) was used for data management and analysis. Findings of the study revealed determinants of type 2 DM grouped as the socio-demographic determinants; tertiary education and marital status, levels of physical activities; lack of vigorous activity and sport, types of diets; high fruits and vegetables and healthy eating out at restaurants, arterial blood pressure; lack of routine BP check and known HPT and types of ARVS used in HIV/AIDS therapy. Compared with patients who received FDC, the risk of type 2 DM was 43 times and 22 higher when a tri-therapy regimen contained Ritonavir and Lopinavir respectively . The majority of DM patients (n=177) were diagnosed type 2 DM after ARVS at n=108 (61%). In managing the diabetic patients a shift from a single disease to multiple-chronic disease focus is required to mitigate the complex drug interactions that exist in the control of NCDs such as HIV/AIDS, DM, HPT and other long-term diseases. The HIV/AIDS and type 2 DM awareness and care intervention strategy is recommended as healthy lifestyle, monitoring of side effects and drug interactions, enhanced FDC roll out and elimination of unsafe ARVS to improve the health outcomes of type 2 DM patients in an HIV/AIDS context in OR Tambo District.
- Full Text:
- Date Issued: 2018
- Authors: Bam, Nokwanda Edith
- Date: 2018
- Subjects: HIV/AIDS Diabetes mellitus (DM) -- Patients Antiretroviral drugs -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD Health Sciences
- Identifier: http://hdl.handle.net/11260/1476 , vital:35976
- Description: Type 2 diabetes mellitus (DM) is a frequent adverse effect of antiretroviral drugs for those who are on ARVS. People with type 2 DM can suffer multiple complications that hinder the quality of life. In South Africa research has shown significant increase in neuropathy, heart and kidney diseases among patients living with type 2 DM and HIV/AIDS compared to DM without HIV. Accessed knowledge lacked consistency on the predictors of DM in HIV/AIDS patients with regards to the type of ARVS with higher risks of DM. Research needed to be done to find the determinants of type 2 DM in HIV/AIDS context. The purpose of this study was to describe the determinants of type 2 DM among HIV/AIDS patients on ARVS in the OR Tambo District, SA in order to develop intervention strategies to mitigate the long-term effects of type 2 DM. A quantitative research methodology using a case control retrospective study was used. A sample of 177 (33%) cases with HIV/AIDS and type 2 DM was selected using a one stage stratified sampling with allocation proportional to size of each stratum of the four sub-districts of OR Tambo District. Two non-diabetic patients with HIV/AIDS were selected as controls per case unpaired and totalled up to 354 (67%) controls. A self-administration questionnaire adopted from the WHO (2011) STEPwise surveillance tool for chronic diseases was used for data collection. Stata (standard version 13.0, Stata Corp., Lakeway Drive USA) was used for data management and analysis. Findings of the study revealed determinants of type 2 DM grouped as the socio-demographic determinants; tertiary education and marital status, levels of physical activities; lack of vigorous activity and sport, types of diets; high fruits and vegetables and healthy eating out at restaurants, arterial blood pressure; lack of routine BP check and known HPT and types of ARVS used in HIV/AIDS therapy. Compared with patients who received FDC, the risk of type 2 DM was 43 times and 22 higher when a tri-therapy regimen contained Ritonavir and Lopinavir respectively . The majority of DM patients (n=177) were diagnosed type 2 DM after ARVS at n=108 (61%). In managing the diabetic patients a shift from a single disease to multiple-chronic disease focus is required to mitigate the complex drug interactions that exist in the control of NCDs such as HIV/AIDS, DM, HPT and other long-term diseases. The HIV/AIDS and type 2 DM awareness and care intervention strategy is recommended as healthy lifestyle, monitoring of side effects and drug interactions, enhanced FDC roll out and elimination of unsafe ARVS to improve the health outcomes of type 2 DM patients in an HIV/AIDS context in OR Tambo District.
- Full Text:
- Date Issued: 2018
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