Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2006. / Includes bibliographical references.

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The work of this thesis was undertaken as a C.A.S.E. award project in collaboration with Rolls-Royce to examine compressible laminar boundary layers with sharp adverse pressure-gradients. Much of the work is devoted to the solution of two important particular problems. The first flow considered is that along a semi-infinite flat plate with uniform pressure when X < X0 and with the pressure for X > X0 being so chosen that the boundary layer is just on the point of separation for all X > X0. Immediately downstream of X0 there is a sharp pressure rise to which the flow reacts mainly in a thin inner sublayer; so inner and outer asymptotic expansions are derived and matched for the stream function and a function of the temperature. Throughout the thesis the ratio of the viscosity to the absolute temperature is taken to be a function of x, the distance along the wall, alone, and the Illingworth-Stewartson transformation is applied. The Prandtl number, σ, is taken to be of order unity and detailed results are presented for σ= 1 and 0.72. The second flow considered is that along a finite flat plate where the transformed external velocity U1(X) is chosen such that U1(X) = u0(-X/L)[super]ε, where O< ε <<1, is the transformed length of the plate and X represents transformed distance downstream from the trailing edge. The skin friction, position of separation and heat transfer right up to separation are determined. On the basis of these two solutions, another solution which is not presented in detail, and a solution (due to Curie) to a fourth sharp pressure gradient problem, a general Stratford-type method for computing compressible boundary layers is derived, which may be used to predict the position of separation, skin friction, heat transfer, displacement and momentum thicknesses for a compressible boundary layer with an unfavourable pressure gradient. In all this work techniques of series analysis are used to good effect. This led us to look at another boundary-layer problem in which such techniques could be used, one in which two parallel infinite disks are initially rotating with angular velocity Ω about a common axis in incompressible fluid, the appropriate Reynolds number being very large. Suddenly the angular velocity of one of the disks is reversed. A new examination of this problem is presented in the appendix to the thesis.

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Ganoderma root rot disease has been reported world wide causing the death of affected hosts. The taxonomy of the genus Ganoderma is considered to be in disarray due to the use of basidiocarp morphological characters to differentiate the species which resulted in many synonyms, species complexes and possible misidentifications of species within the genus. The use of sexual compatibility tests and molecular techniques became powerful diagnostic tools to elucidate the taxonomy of Ganoderma species. Application of these techniques has resolved some of the taxonomic problems but the use of certain species names in the genus is still causing contention among taxonomists. The literature surrounding the taxonomy and techniques used in the taxonomy of the root rot fungus Ganoderma are considered in this thesis. It is clear that the taxonomy of Ganoderma is very difficult and it is still largely obscured by species complexes and incorrect species identifications. It is also evident that a single species concept will not aid in the identification of Ganoderma species. Rather, a combination of concepts based on morphology, mating tests and DNA sequence data should be used in elucidating the taxonomy of Ganoderma. Morphological characteristics as well as nucleotide sequence analysis of three gene regions; the internally transcribed spacer (ITS), the mitochondrial small subunit (mtSSU) and the intergenic spacer (IGS-1), were used to identify the causal agent of Ganoderma root rot of J. mimosifolia in the suburb of Brooklyn, Pretoria, South Africa. Morphological observations and DNA-based phylogenies revealed that all isolates collected from infected trees belong to a single species that reside in the G. lucidum sensu lato complex. Acacia mangium is a leguminous tree that is grown as an exotic plantation species in Indonesia. These economically important trees are threatened by Ganoderma root rot disease. This disease is considered to be the most important cause of losses in A. mangium plantations. Phylogenetic analysis of ITS sequence data showed that G. philippii is the primary agent of Ganoderma root rot in A. mangium in Sumatra, Indonesia. / Dissertation (MSc)--University of Pretoria, 2011. / Microbiology and Plant Pathology / Unrestricted

This thesis reports on the research carried out in the area of Microwave Tomography (MWT) where the study aims to develop inversion algorithms to obtain cheap and stable solutions of MWT inverse scattering problems which are mathematically formulated as nonlinear ill posed problems. The study develops two algorithms namely Inexact Newton Backtracking Method (INBM) and Newton Iterative-Conjugate Gradient on Normal Equation (NI-CGNE) which are based on Newton method. These algorithms apply implicit solutions of the Newton equations with unspecific manner functioning as the regularized step size of the Newton iterative. The two developed methods were tested by the use of numerical examples and experimental data gained by the MWT system of the University of Manchester. The numerical experiments were done on samples with dielectric contrast objects containing different kinds of materials and lossy materials. Meanwhile, the quality of the methods is evaluated by comparingthem with the Levenberg Marquardt method (LM). Under the natural assumption that the INBM is a regularized method and the CGNE is a semi regularized method, the results of experiments show that INBM and NI-CGNE improve the speed, the spatial resolutions and the quality of direct regularization method by means of the LM method. The experiments also show that the developed algorithms are more flexible to theeffect of noise and lossy materials compared with the LM algorithm.

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Caregivers of children with health problems have been demonstrated to show poorer physical and psychological health than caregivers of healthy children. It has been suggested that child behavioural problems are key and account for a large proportion of the variance in caregiver health. Currently, the relation between behaviour problems and caregiver health remains unclear. We conducted a meta-analysis and a secondary data analysis using national data to describe and compare the associations between internalizing and externalizing behaviour problems and caregiver health. Meta-analytical results suggest an association between child behaviour problems and parental stress, depression, and presence of psychiatric symptoms. National data analyses suggested an important association between child behaviour problems, particularly externalizing behaviour problems, and caregiver physical and psychological health when accounting for socioeconomic variables. Results suggest mothers may be more impacted than fathers, and that externalizing behaviour problems may contribute to bigger caregiver health effects than internalizing behaviour problems.