In the present work we initiate the investigation of a stochastic system of evolution partial differential equations modelling the turbulent flows of a bidimensional second grade fluid. Global existence and uniqueness of strong probabilistic solution (but weak in the sense of partial differential equations) are expounded. We also give two results on the long time behavior of the strong probabilistic solution of this stochastic model. Mainly we prove that the strong probabilistic solution of our stochastic model converges exponentially in mean square to the stationary solution of the time-independent second grade fluids equations if the deterministic part of the external force does not depend on time. In the time-dependent case the strong probabilistic solution decays exponentially in mean square. These results are obtained under Lipschitz conditions on the forces entering in the model considered. We also establish the global existence of weak probabilistic solution when the Lipschitz condition on the forces no longer holds. Finally, we show that under suitable conditions on the data we can construct a sequence of strong probabilistic solutions of the stochastic second grade fluid that converges to the strong probabilistic solution of the stochastic Navier-Stokes equations when the stress modulus á tends to zero. All these results are new for the stochastic second-grade fluid and generalize the corresponding results obtained for the deterministic second-grade fluids. / Thesis (PhD)--University of Pretoria, 2011. / Mathematics and Applied Mathematics / unrestricted

Magister Educationis - MEd / The purpose of this study was to investigate the difficulties encountered by the grade ten township learners with respect to the concept of electricity. More specifically, the study attempted to explore the learners’ scientific knowledge by investigating their conceptions or alternative conceptions about electricity; the influence of learners’ age, career interests and gender issues on their conceptions of electricity and; the effectiveness of concept mapping (a pedagogic tool designed by Novak in the 1970s) in facilitating the learners’ understanding of electricity. The study was premised on socio-cultural constructivism as well as meaningful learning as espoused by Ausubel (1968).A Pre-Test-Post-Test Control Group Design was adopted in the study in which two comparable groups were used. The data was analyzed using both qualitative and quantitative research methods and the instruments that were used included a conception of electricity (COET) (originally adopted and administered in the Western Cape, Northern Cape provinces and in Norway in 1999 for the purpose of Science and Technology Literacy Project (STLP) with the hope that their reliability and validity was guaranteed); selected learner interviews and evaluation forms.The summary of findings has suggested that the Grade ten learners held misconceptions about the concept of electricity even after they were exposed to intervention that included concept mapping. In terms of the gender issues, there was no significant difference in performance between the boys and girls though the females outperformed their male counterparts at both groups. The underachievement of the older learners compared to the younger ones has also surfaced and that is against expectation since a number of studies carried out earlier (see Ogunniyi (1999)) have already corroborated such findings. With respect to career interests, what the learners indicated as their future dreams, i.e. what they intend to do and become, seems to have been influenced their performance at the pre- and post-test stages.

Este texto apresenta nosso projeto de implementação de um arcabouço de suporte a agentes móveis dentro de um ambiente de grade denominado InteGrade. Nosso arcabouço - MobiGrid - foi criado de forma a permitir que aplicações seqüenciais longas possam ser executadas em uma rede de estações de trabalho pessoais. Os agentes móveis são utilizados para encapsular essas aplicações com longo tempo de processamento. O encapsulamento de uma aplicação com longo tempo de processamento dentro de um agente móvel é o que denominamos como tarefa. Sendo assim, as tarefas podem migrar sempre que a máquina é requisitada por seu usuário local, já que são providas com capacidade de migração automática. Nosso arcabouço também fornece ao usuário um gerente que rastreia as tarefas por ele submetidas. Baseados no ambiente de execução de tarefas descrito, criamos um modelo matemático para efetuarmos simulações de como se comportariam muitas tarefas submetidas a uma grade com grande quantidade de estações de trabalho. Neste trabalho apresentamos também esse modelo, bem como os resultados das simulações nele baseadas. / This text presents a project which focuses on the implementation of a framework for mobile agents support within a grid environment project, namely InteGrade. Our framework - MobiGrid - was created in such a way that time consuming sequential applications can be executed on a network of personal workstations. The encapsulation of a long processing application by a mobile agent is what we call task. Hence, the tasks can migrate whenever the local machine is requested by its local user, since they are provided with automatic migration capabilities. Our framework also provides the user with a manager that keeps track of the submitted agents. Based on the execution environment described above, we have created a mathematical model which allows us to simulate how a great quantity of tasks submitted to a grid with many workstations would behave. In this text, we also present our model, as well as the results of our simulations.

The thesis will conduct qualitative content analysis, with the help of theories like electoral democracy and Dahl's theory of polyarchal democracy, the thesis will be able to investigate the grade of democracy in the Democratic Republic of Congo. Throughout the research process, I will analyse these theories to measure the grade of democracy in the country. The focus of this thesis is to determine whether the Democratic Republic of the Congo is indeed related to democratic principles. In addition, I introduced previous reports, documents and theories to measure the grade of democracy in the Democratic Republic of Congo. I analysed the views on these reports and documents by identifying the elements that describe democratic countries and using them to measure the democratic hierarchy of the Democratic Republic of the Congo. Elements such as freedom of expression, fair and free election and many others. These elements are studied to give a conclusion on the measurement of democracy in the Democratic Republic of Congo. Finally, I conclude my research by presenting measures related to country ́s democracy. However, the Democratic Republic of Congo have failed to establish contact with democratic principles which has led to a lower grade of democracy.

付記する学位プログラム名: 充実した健康長寿社会を築く総合医療開発リーダー育成プログラム / 京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第22121号 / 医科博第106号 / 新制||医科||7(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 濵﨑 洋子, 教授 河本 宏, 教授 生田 宏一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

In order to compete in the 21st century, it is vital for policymakers and school leaders to create technology-based classrooms for teaching and learning. Teachers are of significant importance in implementing information and communication technology (ICT) in schools. The purpose of this study was to explore Grade 5 mathematics teachers’ experiences of using ICT in teaching and learning. Furthermore, this study explored how the available resources are used, as well as the challenges that teachers experience to implement ICT tools in their lessons. This study determined how teachers perceive the use of ICT in teaching and learning. Also, the researcher addressed the professional development, technical training, as well as support the teachers received at their respective schools. The primary research question for this study is: “How do Grade 5 mathematics teachers from well-resourced schools experience the use of ICT within their classrooms?” The qualitative approach was used, and a descriptive case study research design was selected to answer the research question. The technology acceptance model (TAM) was used as a basis to determine the themes of the study. The data collection strategies were questionnaires and semi-structured interviews to determine teachers’ experiences of using ICT in the mathematics classroom. Purposive and convenience sampling were used to select the participants for this study. The participants comprised six mathematics teachers from three well-resourced and independent schools located in Tshwane, South Africa. An overall conclusion is that this study reveals mixed feelings of both optimism and reluctance when using ICT in mathematics. The results prove differences in teachers’ perceived experiences of ICT in mathematics teaching and learning. The individual schools as well as the teachers received different levels of training, professional development and support from the institution, and also face external and internal barriers when integrating ICT into the classroom. However, despite these barriers, it is still clear that ICT is the future of learning. It is always important to understand that the responses of the participants represent their own perceptions. / Dissertation (MEd)--University of Pretoria, 2020. / Science, Mathematics and Technology Education / MEd / Unrestricted

Using data on 9th grade students in Sweden for the time period of 2015-2019, this paper estimates a fixed effects model to find out whether the share migrant students has any impact on the grade of foreign-born and native Swedish students. We find that increasing the share of migrant students by one percentage point has a small negative effect on foreign-born students, but find no conclusive evidence from the same effect on Swedish students. Furthermore, we find the effect to be the largest when the share of migrants in a municipality is high, suggesting that redistribution of migrants across municipalities would decrease the negative effect of an increase in migrant students.

Magister Educationis - MEd / This study analysed the modelling competencies of grade 11 learners and also explored the degree to which the learners’ competency in setting up a mathematical model inhibits the development of an acceptable solution for word problems. The research data comprised 30 learners drawn from a secondary school in the Western Cape Province, South Africa. Data was collected via a task-based activity response sheet containing five word problems linked to either one of the following concepts: rectangle, two-digit number, average speed and petrol price. Learners’ responses were graded into four categories viz: correct, partially correct, incorrect and no response. Thereafter, the modelling competency framework was used to diagnose the modelling competencies of the sampled learners.

The investigator has undertaken this study to determine whether the present orientation course at Oakdale High School meets the needs of youth whom it serves. Interest in the problem was aroused through controversy form time to time regarding the practicability of such a course as part of the curriculum, since some of the high schools in the county either do not have, or no longer include, Orientation in the curriculum as a separate course.

A sequence of 3250 m of the Rustenburg Layered Suite and its associated mineralization south of Potgietersrus was investigated. Four episodes of faulting have deformed the area. This resulted in very early differentiates, not seen elsewhere in the Bushveld Complex, to outcrop together with economic concentrations of the best metallurgical grade chromite presently being mined in the Republic. The Mg:Fe:Ca ratio of theCa-poor pyroxenes varies from 89,5:8,8:1,6 in the lower zone to 44,2:52,3:3,37 in the upper zone. The latter composition demarcates the Fe-rich end of the two pyroxene limit. Textural evidence implies that there is a peritectic reaction between the ironrich Ca-poor pyroxene and the melt and that this may account for the termination of the two pyroxene field. A significantly higher mean Ko~~~F~p; for the study area (0,822) than for the other sectors of the Bushveld Complex (0,782) suggests that the pyroxenes of similar composition crystallized at higher temperatures in the Potgietersrus limb. Examination of the Al :Si ratio in Ca-rich pyroxenes from a variety of magmatic environments confirms that this variable can be used to monitor relative changes in the a ~~~t. Chemical data of the Ca-rich pyroxenes suggest that this phase define~ an Fe enrichment - Ca depletion trend during differentiation uhlike that for most other tholeiitic intrusions. The V205 content of the main magnetitite layer and the cr203 and the Cr/Fe2++Fe3+ values in the upper and lower chromitite layers in the study area are the highest encountered in the Bushveld Complex. Textural evidence in these layers show that they have been up-graded to dense monomineralic layers by postcumulus sintering. Calculated intensive parameters for the Potgietersrus magma suggest that it crystallized over a temperature interval from 1276°C in the lower zone to 1022°C in the basal portion of the upper zone. Oxygen fugacity conditions for the lower zone ranged from 10-6,21 to 10-4,98 atm whereas lower values of 1o-11 to 1o-9 atm were operative in the upper zone. The study area contains abundant concentrations of sulfides at several levels in the sequence. The separation of the sulfide liquid is related in most cases to new influxes of metal-rich magma and mixing with the residual magma in the chamber. Several definite sulfide facies occur in the layered sequence. Sulfur isotope investigations indicate that all the sulfur in the study area is mantle derived and that the isotopic composition of the sulfur was controlled by the prevailing fo2, which in turn controlled the partitioning of S02 and HzS between sulfide melt and magma. / Thesis (PhD)--University of Pretoria, 1983. / gm2014 / Materials Science and Metallurgical Engineering / Unrestricted