The purpose of this study is to identify aspects of successful Advanced Placement programs in small schools of enrollments of 600 or fewer, and to describe the strategies that are used in these schools to make their programs successful. The study includes a pilot research project with a small school with a floundering program identifying the major problems that it has faced in starting and creating its program along with cases of two additional small schools that have found success with their programs. The cases of the successful schools are analyzed to find the aspects of the programs that have led to their success to provide struggling schools with suggestions for improvements of their programs.

No description available.

No description available.

Attempts have been made to synthesise a novel siloxane-containing dicyanate ester, 1,3-bis(4-cyanatophenyl)-1,1,3,3-tetramethyldisiloxane, commencing from 4-bromophenol or 4-methoxyphenol. Most of these syntheses have involved the use of a Grignard reaction to form a disiloxane group, followed up subsequent cleavage of an alkyl-protecting group to yield a free phenol. Several different ethers have been attempted, but none was successful. The extreme susceptibility of the aryl silicon-carbon bond to cleavage under acidic conditions has been demonstrated by these reactions. A novel phosphazene-containing dicyanate ester, 1,3-bis(4-cyanatophenyl)-1,3,5,5-tetraphenoxycyclotriphosphazene has been successfully synthesised in a four-step procedure with an overall yield of ca. 35%. The cyanate ester has been characterised by differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, thermomechanical analysis (TMA), 1H, 13C and 13P NMR spectroscopy, and Fourier-Transform Infra-red (FT-IR) and Raman spectroscopy. The thermal data collected showed a surprisingly low glass transition temperature (59 °C) and enthalpy of polymerisation (ca. 36-5 kJ mol-1 of cyanate). The former figure was confirmed by TMA and modulated DSC. However, the cured cyanate showed reasonably high thermal stability: no mass loss was observed before 300 °C. Total decomposition did not occur until about 650 °C.

A variety of species distribution models (SDMs) were fit to data collected by a 15,000km road-side visual survey of Aloidendron dichotomum populations in the Northern Cape region of South Africa, and Namibia. We fit traditional presence/absence SDMs as well as SDMs on how proportions are distributed across three species stage classes (juvenile, adult, dead). Using five candidate machine learning methods and an ensemble model, we compared a number of approaches, including the role of balanced class (presence/absence) datasets in species distribution modelling. Secondary to this was whether or not the addition of species’ absences, generated where the species is known not to exist have an impact on findings. The goal of the analysis was to map the distribution of Aloidendron dichotomum under different scenarios. Precipitation-based variables were generally more deterministic of species presence or lack thereof. Visual interpretation of the estimated Aloidendron dichotomum population under current climate conditions, suggested a reasonably well fit model, having a large overlap with the sampled area. There however were some conditions estimated to be suitable for species incidence outside of the sampled range, where Aloidendron dichotomum are not known to occur. Habitat suitability for juvenile individuals was largely decreasing in concentration towards Windhoek. The largest proportion of dead individuals was estimated to be on the northern edge of the Riemvasmaak Conservancy, along the South African/Namibian boarder, reaching up to a 60% composition of the population. The adult stage class maintained overall proportional dominance. Under future climate scenarios, despite maintaining a bulk of the currently habitable conditions, a noticeable negative shift in habitat suitability for the species was observed. A temporal analysis of Aloidendron dichotomum’s latitudinal and longitudinal range revealed a potential south-easterly shift in suitable species conditions. Results were however met with some uncertainty as SDMs were uncovered to be extrapolating into a substantial amount of the study area. We found that balancing response class frequencies within the data proved not to be an effective error reduction technique overall, having no considerable impact on species detection accuracy. Balancing the classes however did improve the accuracy on the presence class, at the cost of accuracy of the observed absence class. Furthermore, overall model accuracy increased as more absences from outside the study area were added, only because these generated absences were predicted well. The resulting models had lower estimated suitability outside of the survey area and noticeably different suitability distributions within the survey area. This made the addition of the generated absences undesirable. Results highlighted the potential vulnerability of Aloidendron dichotomum given the pessimistic, yet likely future climate scenarios.

Includes bibliographical references. / The Companies Act 61 of 1973 (the "1973 Act") will be repealed in its entirety when the Companies Act 71 of 2008 (the "2008 Act") comes into operation on a date still to be fixed by the President of the Republic of South Africa, in proclamation. The goal of this dissertation is to investigate what impact, if any, the 2008 Act will have on the remedies afforded to members or shareholders in companies to protect their rights in the event of so-called "oppressive or unfairly prejudicial conduct" by majority decision, or otherwise, in a company.

Emergency responders are expected to perform high-quality CPR on an array of body physiques, regardless of the presence of protective equipment. The purpose of this study was to examine rescuers? administration of CPR on traditional and endomorphic manikins with and without football shoulder pads (FBSP). Fifty emergency responders completed two compression-only scenarios following 2015 AHA CPR Guidelines: 1) removal of FBSP before initiating chest compressions, and 2) performing chest compressions over FBSP. There was a statistically significant effect with a decrease in compression rate and depth with the presence of FBSP. For chest recoil, there was a statistically significant effect due to manikin type and presence of FBSP. Based on these findings, emergency responders are not equipped to perform high-quality CPR in all scenarios. Additionally, utilization of a diverse range of manikin physiques should be a consideration in the advancement of CPR education for emergency responders.

The thesis considers the general area of robust portfolio construction. In particular the thesis considers two techniques in this area that aim to improve portfolio construction, and consequently portfolio performance. The first technique focusses on estimation error in the sample covariance (one of portfolio optimisation inputs). In particular shrinkage techniques applied to the sample covariance matrix are considered and the merits thereof are assessed. The second technique considered in the thesis focusses on the portfolio construction/optimisation process itself. Here the thesis adopted the 'resampled efficiency' proposal of Michaud (1989) which utilises Monte Carlo simulation from the sampled distribution to generate a range of resampled efficient frontiers. Thereafter the thesis assesses the merits of combining these two techniques in the portfolio construction process. Portfolios are constructed using a quadratic programming algorithm requiring two inputs: (i) expected returns; and (ii) cross-sectional behaviour and individual risk (the covariance matrix). The output is a set of 'optimal' investment weights, one per each share who's returns were fed into the algorithm. This thesis looks at identifying and removing avoidable risk through a statistical robustification of the algorithms and attempting to improve upon the 'optimal' weights provided by the algorithms. The assessment of performance is done by comparing the out-of-period results with standard optimisation results, which highly sensitive and prone to sampling-error and extreme weightings. The methodology looks at applying various shrinkage techniques onto the historical covariance matrix; and then taking a resampling portfolio optimisation approach using the shrunken matrix. We use Monte-Carlo simulation techniques to replicate sets of statistically equivalent portfolios, find optimal weightings for each; and then through aggregation of these reduce the sensitivity to the historical time-series anomalies. We also consider the trade-off between sampling-error and specification-error of models.

Includes bibliographical references. / This dissertation evaluates the regulation of domestic work. It approaches this topicfrom an international and national perspective. An international perspective in thiscontext means the regulation of domestic work as an international labour standard bythe International Labour Organization (ILO). Its national perspective entails the variousmodels of national regulation in three countries- South Africa Namibia and Indonesia.This dissertation also brings to the fore the nature of domestic work in its evaluation as a labour standard. It does this to give a general understanding of the subject. In recent years, regulating domestic work has been a popular topic within international labour law circles. However, the popularity of this discussion is not reflected in the working lives of a majority of domestic workers worldwide. Therefore, this dissertation reiterates specific issues that affect the lives of domestic workers in a bid to contribute to the body of knowledge on the subject; and the achievement of social justice and decent work in this “invisible' sector.This dissertation concludes that the proper regulation of the domestic work sector is the first step in the achievement of social justice for domestic workers. It also posits after a comparative analysis that the regulation of decent work requires a framework in which hard and soft law approaches are interwoven in the regulation of domestic work. This framework is important as the intertwining of hard and soft law regimes will enable the reaffirmation of and compliance with ILO standards for domestic work regulation. National legislation of ILO member states also have to be fine-tuned or amended to this dissertation reiterates specific issues that affect the lives of domestic workers in a bid to contribute to the body of knowledge on the subject; and the achievement of social justice and decent work in this 'invisible' sector. This dissertation concludes that the proper regulation of the domestic worksector is the first step in the achievement of social justice for domestic workers. It also posits after a comparative analysis that the regulation of decent work requires a framework in which hard and soft law approaches are interwoven in the regulation of domestic work. This framework is important as the intertwining of hard and soft law regimes will enable the reaffirmation of and compliance with ILO standards for domestic work regulation.

Discrete phylogeographic models enable the inference of the geographic history of biological organisms along phylogenetic trees. Frequently applied in the context of epidemiological modelling, phylogeographic generalised linear models were developed to allow for the evaluation of multiple predictors of spatial diffusion. The standard phylogeographic generalised linear model formulation, however, assumes that rates of spatial diffusion are a noiseless deterministic function of the set of covariates, admitting no other unobserved sources of variation. Under a variety of simulation scenarios, we demonstrate that the lack of a term modelling stochastic noise results in high false positive rates for predictors of spatial diffusion. We further show that the false positive rate can be controlled by including a random effect term, thus allowing unobserved sources of rate variation. Finally, we apply this random effects model to three recently published datasets and contrast the results of analysing these datasets with those obtained using the standard model. Our study demonstrates the prevalence of false positive results for predictors under the standard phylogeographic model in multiple simulation scenarios and, using empirical data from the literature, highlights the importance of a model accounting for random variation.