A review of generalized linear models for count data with emphasis on current geospatial procedures
- Authors: Michell, Justin Walter
- Date: 2016
- Subjects: Spatial analysis (Statistics) , Bayesian statistical decision theory , Geospatial data , Malaria -- Botswana -- Statistics , Malaria -- Botswana -- Research -- Statistical methods
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:5582 , http://hdl.handle.net/10962/d1019989
- Description: Analytical problems caused by over-fitting, confounding and non-independence in the data is a major challenge for variable selection. As more variables are tested against a certain data set, there is a greater risk that some will explain the data merely by chance, but will fail to explain new data. The main aim of this study is to employ a systematic and practicable variable selection process for the spatial analysis and mapping of historical malaria risk in Botswana using data collected from the MARA (Mapping Malaria Risk in Africa) project and environmental and climatic datasets from various sources. Details of how a spatial database is compiled for a statistical analysis to proceed is provided. The automation of the entire process is also explored. The final bayesian spatial model derived from the non-spatial variable selection procedure using Markov Chain Monte Carlo simulation was fitted to the data. Winter temperature had the greatest effect of malaria prevalence in Botswana. Summer rainfall, maximum temperature of the warmest month, annual range of temperature, altitude and distance to closest water source were also significantly associated with malaria prevalence in the final spatial model after accounting for spatial correlation. Using this spatial model malaria prevalence at unobserved locations was predicted, producing a smooth risk map covering Botswana. The automation of both compiling the spatial database and the variable selection procedure proved challenging and could only be achieved in parts of the process. The non-spatial selection procedure proved practical and was able to identify stable explanatory variables and provide an objective means for selecting one variable over another, however ultimately it was not entirely successful due to the fact that a unique set of spatial variables could not be selected.
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- Date Issued: 2016
Taxing the Minerals Sector in South Africa: a comparative analysis of the proposed tax model for South Africa and the models adopted in selected African countries
- Authors: Van den Berg, Jana
- Date: 2015
- Subjects: Industrial minerals -- Taxation -- South Africa , Industrial minerals -- Taxation -- Developing countries , Industrial minerals -- Law and legislation -- South Africa , Industrial minerals -- Law and legislation -- Developing countries
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:919 , http://hdl.handle.net/10962/d1017545
- Description: The State Intervention in the Minerals Sector Report emerged as a resolution during the 3rd National General Council Resolution on Economic Transformation held in 2012, during which the Council stated that: “The ANC’s approach to economic transformation of the South African economy should always be holistic and comprehensive, covering all sectors of the economy. In this regard, the ANC should ensure greater state involvement and control of strategic sectors of the economy, such as mining, energy, the financial sector and others.” It was for this reason that the National General Council mandated the National Executive Committee to ensure that further work be done on ways in which the African National Congress can implement economic transformation in sectors such as the mining industry. It was suggested that methods including research, study tours and discussions be conducted to gather the required information. As a result of the research, The State Intervention in the Minerals Sector Report emerged. In The State Intervention in the Minerals Sector Report, the mineral sectors of developed as well as developing countries are compared with each other. The developing countries compared included Botswana, Zambia, Ghana, Liberia and Sierra Leone, and these countries have also been selected for the purpose of comparison in the present research. The goal of this study is to analyse the recommendations made in The State Intervention in the Minerals Sector Report regarding State involvement in the minerals sector. To determine whether the economic situation in South Africa is comparable to the five other African countries, an analysis based on demographic indicators, the history of the minerals sector in the various countries, its contribution to the fiscal regime of that country, its economic contribution, as well as the extent of involvement from Government and the model implemented for its involvement, is conducted. According to a work paper published by the World Bank on the world development indicators for 2014, control over metal supply to the economy has been considered vital for political and economic reasons in most societies. It further states that most State-owned mining companies have over the years and, in particular, in developing countries, not been able to operate successfully, leading to privatisation. Poor performance is, however, not necessarily the reason for State ownership. Areas not addressed by this thesis include the Gold Mining industry in South Africa and the Diamond mining industry in Botswana.
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- Date Issued: 2015