Seyoum A.,Bahir Dar University |
Ndlovu P.,UNISA |
Temesgen Z.,University of KwaZulu - Natal
AIDS Research and Therapy | Year: 2017
Background: Adherence and CD4 cell count change measure the progression of the disease in HIV patients after the commencement of HAART. Lack of information about associated factors on adherence to HAART and CD4 cell count reduction is a challenge for the improvement of cells in HIV positive adults. The main objective of adopting joint modeling was to compare separate and joint models of longitudinal repeated measures in identifying long-term predictors of the two longitudinal outcomes: CD4 cell count and adherence to HAART. Methods: A longitudinal retrospective cohort study was conducted to examine the joint predictors of CD4 cell count change and adherence to HAART among HIV adult patients enrolled in the first 10 months of the year 2008 and followed-up to June 2012. Joint model was employed to determine joint predictors of two longitudinal response variables over time. Furthermore, the generalized linear mixed effect model had been used for specification of the marginal distribution, conditional to correlated random effect. Results: A total of 792 adult HIV patients were studied to analyze the longitudinal joint model study. The result from this investigation revealed that age, weight, baseline CD4 cell count, ownership of cell phone, visiting times, marital status, residence area and level of disclosure of the disease to family members had significantly affected both outcomes. From the two-way interactions, time * owner of cell phone, time * sex, age * sex, age * level of education as well as time * level of education were significant for CD4 cell count change in the longitudinal data analysis. The multivariate joint model with linear predictor indicates that CD4 cell count change was positively correlated (p ≤ 0.0001) with adherence to HAART. Hence, as adherence to HAART increased, CD4 cell count also increased; and those patients who had significant CD4 cell count change at each visiting time had been encouraged to be good adherents. Conclusion: Joint model analysis was more parsimonious as compared to separate analysis, as it reduces type I error and subject-specific analysis improved its model fit. The joint model operates multivariate analysis simultaneously; and it has great power in parameter estimation. Developing joint model helps validate the observed correlation between the outcomes that have emerged from the association of intercepts. There should be a special attention and intervention for HIV positive adults, especially for those who had poor adherence and with low CD4 cell count change. The intervention may be important for pre-treatment counseling and awareness creation. The study also identified a group of patients who were with maximum risk of CD4 cell count change. It is suggested that this group of patients needs high intervention for counseling. © 2017 The Author(s).
African Journal of Research in Mathematics, Science and Technology Education | Year: 2010
The study examined the difference in performance of boys and girls in solving problems on the properties of a rectangle. The conceptual framework of the study was based on the idea that teaching the learners content in a familiar context tends to facilitate geometry learning. The data were collected using semi-structured interviews with the teachers and a mixed-gender purposeful sample of their learners and statistical techniques involving the use of t-test to compare the percentage mean scores of the gender groups. The results showed that there was a statistically significant difference in the achievement test's scores across the gender groups with boys scoring higher and that the difference seems to be due to the manifestation of cultural stereotypes in class. © 2010 Taylor & Francis Group, LLC.
Adebayo I.,Tshwane University of Technology |
Jimoh A.A.,Tshwane University of Technology |
IET Generation, Transmission and Distribution | Year: 2017
Electrical power grids are often susceptible to voltage instability and have been a growing concern. In this study, the authors propose techniques based on network response structural characteristics for voltage stability assessment and for the identification of important nodes in electrical power grids. First, the network response structural characteristic indices (NRSCIs) which are inherent in the conventional power grids in terms of the Kirchhoff matrix is formulated. The eigenvalue decomposition (ED) technique is then applied to a submatrix of the Kirchhoff matrix to determine the topological strength of the electrical network graph. The vertex (node) that has a minimum eigenvalue is taken as the critical mode, from which its contributions to the entire graph is identified using the proposed network response structural characteristics theory participation factor (NRSCTPF). To demonstrate the magnitude of the concept formulated, the known degree centrality is modified in terms of the established NRSCI, which are then used to determine the important nodes of the network graph. The results obtained show that the proposed NRSCTPF and the degree centrality based on the NRSCI can be used for voltage stability assessment and identification of important nodes. The proposed approach is also less computationally intensive compared with the traditional approach. © 2017 The Institution of Engineering and Technology.
Matabola K.P.,UNISA |
Van Der Merwe E.M.,University of Pretoria |
Strydom C.A.,North West University South Africa |
Labuschagne F.J.W.,University of Pretoria
Journal of Chemical Technology and Biotechnology | Year: 2010
BACKGROUND: The influence of different hydrating agents on the pH of the hydrating solutions, rate of hydration of MgO to Mg(OH)2 and product surface area was studied as a function of temperature of hydration. Hydrating agents used were aqueous solutions of ammonium chloride, magnesium acetate, magnesium nitrate, nitric acid, acetic acid, magnesium chloride, sodium acetate and hydrochloric acid and distilled water as control. These were chosen to determine either the effect of addition of a common ion, the effect of changing the solution pH or due to the presence of an acetate ion, found earlier to have a beneficial effect on the hydration of MgO. RESULTS: There was no significant difference in the hydration behaviour of the hydrating agents up to 50 °C, where less than 10% of magnesium hydroxide was formed. The amount of hydroxide increased at temperatures above 60 °C. When compared with the hydration in water, all the hydrating agents, with the exception of sodium acetate, showed a significant increase in the degree of hydration. Sodium acetate formed the lowest amount of magnesium hydroxide, ranging between 1.2 and 12.2% magnesium hydroxide. The largest percentage (56.7%) of magnesium hydroxide was formed from hydration in magnesium acetate. CONCLUSION: It seems that MgO hydration is a dissolution-precipitation process controlled by the dissolution of MgO. The increased degree of hydration in magnesium acetate is possibly due to the presence of acetate and Mg2+ ions. © 2010 Society of Chemical Industry.
Environment, Development and Sustainability | Year: 2015
For more than a century, the mining sector has played a crucial role in the economic development of South Africa. However, it also causes immense harm to the country’s people and environment. Gold and coal mining have serious implications for water management. The problem arises when contaminated water in the form of acid mine drainage (AMD) reaches the river basin systems and affects water usages important for socio-economic development. This article looks at the impacts of AMD on different constituencies in the Witwatersrand Basin for the South African society and on sustainable socio-economic development. It includes different responses by the media, civil society, scientists and Government on AMD, how they interpret AMD and its effects on socio-economic development. © 2014, Springer Science+Business Media Dordrecht.
Sivaramakrishna A.,Vellore Institute of Technology |
Clayton H.S.,UNISA |
Muralikrishna U.,Andhra University
Journal of Coordination Chemistry | Year: 2011
This review provides an overview of the synthetic pathways, structures, and reactivity of various nickel(IV) complexes. The complexes are classified according to the various ligand types including sulfur, oxygen, nitrogen, and phosphorus donors. The main emphasis is on different ligand systems which stabilize Ni in higher oxidation state in the solid state and solution. The structural aspects of the complexes are briefly discussed. The possible applications of these nickel(IV) complexes are reviewed and future prospects are also highlighted. © 2011 Taylor & Francis.
2016 IST-Africa Conference, IST-Africa 2016 | Year: 2016
This paper argues that successful provision of mobile centric services in teaching and learning is dependent on the readiness of lectures and the supporting institutional policies. The basis of this claim is an empirical investigation undertaken as a qualitative single case study at an ODL university in South Africa. The evidence was gathered through lecturer interviews and policy document analysis. Both lecturer interview data and policy document analysis data were qualitatively analysed. The findings of this study revealed that successful provision of mobile centric services in teaching and learning depends on the readiness of lecturers and the readiness of institutional policies in supporting the lecturers. © 2016 IIMC.
Olivier J.,UNISA |
Venter J.,Council for Geoscience |
Water SA | Year: 2011
In many countries thermal springs are utilised for a variety of purposes, such as the generation of power, direct space heating, industrial processes, aquaculture and many more. The optimal use of a thermal spring is largely dependent upon its physical and chemical characteristics. This article focuses on the thermal and chemical features of 8 thermal springs located in the northern part of the Limpopo Province, South Africa. Field data and water samples were collected from Evangelina, Tshipise, Sagole, Môreson, Siloam, Mphephu, Minwamadi and Die Eiland for analysis of physical and chemical parameters. The temperatures at source vary from 30°C to 67.5°C. The springs are associated with faults and impermeable dykes and are assumed to be of meteoric origin. The mineral composition of the thermal waters reflects the geological formations found at the depth of origin. None of the spring waters are fit for human consumption since they contain unacceptably high levels of bromide ions. Six springs do not conform to domestic water quality guidelines with respect to fluoride levels. Unacceptably high values of mercury were detected at Môreson and Die Eiland. Spring water at Evangelina is contaminated with selenium and arsenic. It is important to keep such limitations in mind when determining the ultimate use of the thermal springs.
News Article | November 1, 2016
Author Khoza Mduduzi has long noticed the economic plight of the African people, wherein they are forced to scrape by on meager earnings while their own country is being ransacked by foreign powers. In “The West Stole Africa's Wealth” (published by Xlibris) the author opens readers' eyes to the truth on how western countries have been monopolizing South African resources for years. “The West Stole Africa's Wealth” is a truly informative read that shows the dark side of western interference with South African affairs. It documents and proves once and for all the avarice and cruelty of the west towards the African people and the African continent. It also shows how the western powers were able to hold on to their ill-gotten gains and positions by sowing discord in the African countries, thus preventing them from being a united force. The information contained in this highly immersive read was predominantly gathered from African countries such as Zimbabwe, countries that have had a history of being used by foreign powers. It also shows the long history of slave trade conducted within the African continent. The author’s main aim is to open the reader’s eyes to the many injustices suffered by the African people under western hands and to show the African people their potential for political and economic growth. About the Author Khoza Mduduzi holds a Bachelor of Commerce Degree from the University of Venda for Science and Technology and Post Graduate Certificate in Education (PGCE) from the University of South Africa (UNISA). He is an educator by profession and registered with the South African Council of Educators (SACE). He visited Zimbabwe prior the July 31, 2013 national elections and again visited Zimbabwe post the July 31, 2013 elections. He is a critical rationalist who has a keen interest in African politics and African affairs. This is his first book on the number of books that are still yet to be published. Xlibris Publishing, an Author Solutions, LLC imprint, is a self-publishing services provider created in 1997 by authors, for authors. By focusing on the needs of creative writers and artists and adopting the latest print-on-demand publishing technology and strategies, we provide expert publishing services with direct and personal access to quality publication in hardcover, trade paperback, custom leather-bound and full-color formats. To date, Xlibris has helped to publish more than 60,000 titles. For more information, visit xlibris.com or call 1-888-795-4274 to receive a free publishing guide. Follow us @XlibrisPub on Twitter for the latest news.
News Article | November 4, 2016
With an upcoming publication in the Worldwide Leaders in Healthcare, Claudia Baird, RN, joins the prestigious ranks of the International Nurses Association. She is a Registered Nurse with 25 years of experience in her field and an extensive expertise in all facets of nursing, especially wound care, stomal therapy, and IV therapy. Claudia is currently serving patients as Stomal Therapist and Case Coordinator at Royal District Nursing Service in Adelaide, South Australia. Claudia received her diploma in Midwifery, Community Health, Psychiatric and General Nursing in 1991 from Ann Latsky College. In 1996, she acquired her diploma in Nursing Administration from the University of Pretoria in South Africa, prior to completing her Bachelor degree in Health Science and Education in Nursing from UNISA. Additionally, Claudia holds certificates in stomal therapy, immunization, and frontline management. To keep current in the newest developments in her field, Claudia maintains professional memberships with the Australian Infection Control Association, and the Australian Wound Management Association. Claudia attributes her success to her hard work and passion. When she is not assisting patients, Claudia enjoys reading, painting, and embroidery. Learn more about Claudia Baird here: http://inanurse.org/network/index.php?do=/4133350/info/ and read her upcoming publication in the Worldwide Leaders in Healthcare.