3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Multiplicity features of simple models for spontaneous combustion in coal stockpiles(2010-02-19T11:01:15Z) Raftopoulos, EkateriniItem Introducing the moon to South African natural science classrooms(2009-04-08T11:36:42Z) Kelfkens, LesleyThis dissertation concerns the the problem that natural science teachers with limited astronomy backgrounds have to teach new curriculum content about lunar motion, phases and eclipses. My study aims to establish: 60 teachers’ knowledge of lunar phenomena through surveys; whether an intervention incorporating models and activities is effective at improving a case study group’s understandings; how the case study teachers use these activities and models in the classroom. My results indicate that the majority of natural science teachers have little formal astronomy education. Only two teachers held a scientific understanding of lunar phenomena. The intervention led towards a more scientific understanding amongst the case study group. Scale is essential for developing an understanding of lunar phenomena and models are extremely beneficial, but participants experience spatial problems when viewing models from an external perspective. I propose in-service training in small groups for building knowledge and increasing confidence for teaching this content.Item A statistical investigation into the properties and dynamics of biological populations experiencing environmental variability(2007-02-15T11:30:22Z) Varughese, Melvin MathewMuch research has been devoted towards the understanding of population behaviour. Such understanding has often been furthered through the development of theoretical population models. This research report explores a variety of population models and their implications. The implications of the various models are explored using both analytical results and simulations. Specific aspects of population behaviour studied include gross fluctuation characteristics and extinction probabilities for a population. This research report starts with an overview of Deterministic Models. This is followed by a study of Birth and Death Processes, Branching Processes and Models that incorporate environmental variability. Finally, we study the maximum likelihood approach to population parameter estimation. The more notable theoretical results derived include: the development of models that incorporate the population’s history; models that incorporate discontinuous environmental changes and the development of a means of parameter estimation for a Stochastic Differential Equation.