The purposes of the study are to find ways of improving children's written self-expression and to consider the economy of a more effective use of the transitional stage of learning when words recognized are becoming words used in self-expression.

Syftet med studien är att bidra med kunskaper om humor i svenskundervisningen i årskurs 4–6. Frågeställningarna som besvaras är hur lärare ser på humoranvändande i svenskundervisningen, samt deras användande av humor. För att uppnå syftet har semistrukturerade intervjuer använts och de teoretiska utgångspunkterna för arbetet är den sociokulturella teorin, inkongruensteorin samt Shannon och Weavers kommunikationsmodell. Resultatet visar att lärarna ser både möjligheter och utmaningar gällande humoranvändande men att det med en viss fingertoppskänsla kan gynna elevernas lärande och lärmiljö. Det har även visat sig av studien att de intervjuade lärarna använder sig av humor i svenskundervisningen med syfte att skapa ett roligare innehåll och ett tryggare klassrumsklimat. / The purpose of the study is to contribute with knowledge about humor in Swedish education in grades 4−6. The research questions addressed are how teachers view the use of humor in Swedish language teaching, and their potential use of humor. To achieve this purpose, semi−structured interviews were conducted and the theoretical framework for the study are the sociocultural theory, incongruity theory and Shannon and Weaver’s communication model. The results show that teachers see both opportunities and challenges regarding the use of humor, but with a certain level of sensitivity, it can benefit students’ learning and the learning environment. The study also revealed that the interviewed teachers use humor in Swedish teaching with the aim of creating more engaging content and a safer classroom climate.

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The aim of this study was to identify high school student’s thoughts and experiences about discrimination based on background. Six students, all with foreign origin, was interviewed where different questions about discrimination and stigmatization was asked. The results of this qualitative research show that there are students who are experiencing discrimination based on their origin and that the discrimination differs very much dependently on how deviant the person is from the swedes in terms of background and appearance. Students with foreign origin notice how this affects their conditions and possibilities in school where they are more easily categorized and stigmatized as worse. This is a problem that should be recognized not least because the teacher as official has an obligation to treat every student equally but also because the proceeding discrimination contributes to the maintenance of existing ethnical power hierarchies.

Through distance learning, the community college system has been able to serve more students by providing educational opportunities to students who would otherwise be unable to attend college. The community college of focus in the study increased its online enrollments and online course offerings due to the growth of overall enrollment. The need and purpose of the study is to address if there is a difference in students’ grades between face-to-face and online biology related courses and if there are differences in grades between face-to-face and online biology courses taught by different instructors and the same instructor. The study also addresses if online course delivery is a viable method to educate students in biology-related fields. The study spanned 14 semesters between spring 2006 and summer 2011. Data were collected for 6,619 students. For each student, demographic information, cumulative grade point average, ACT, and data on course performance were gathered. Student data were gathered from General Biology I, Microbiology of Human Pathogens, Human Anatomy and Physiology I, and Human Anatomy and Physiology II courses. Univariate analysis of variance, linear regression, and descriptive analysis were used to analyze the data and determine which variables significantly impacted grade achievement for face-to-face and online students in biology classes. The findings from the study showed that course type, face-to-face or online, was significant for Microbiology of Human Pathogens and Human Anatomy and Physiology I, both upper level courses. Teachers were significant for General Biology I, a lower level course, Human Anatomy and Physiology I, and Human Anatomy and Physiology II. However, in every class, there were teachers who had significant differences within their courses between their face-to-face and online courses. This study will allow information to be concluded about the relationship between the students’ final grades and class type, face-to-face or online, and instructor. Administrators, faculty and students can use this information to understand what needs to be done to successfully teach and enroll in biology courses, face-to-face or online.

Lead is a toxic heavy metal that has been extensively used in modern society, causing widespread environmental contamination, even in isolated parts of the world. There is now overwhelming evidence associating lead exposure with wideranging health effects, including reductions in intelligence scores, hyperactivity, shortened concentration spans, poor school performance, violent/aggressive behaviour, hearing loss, delayed onset of puberty, anaemia, and in severe cases, coma and death. In recent years consensus has been reached in respect of the absence of a threshold of safety for key health effects associated with lead exposure, and the permanent and irreversible nature of many of the health and social consequences of exposure to lead. The public health problem of environmental lead exposure has been widely investigated in developed countries such as the United States of America where, since the 1970s, policies and interventions have been followed by significant reductions in blood lead levels amongst children. In developing countries, and in African countries in particular, there is a relative dearth of information on the sources, mechanisms of exposure and blood lead distributions in children, and little action has been taken to protect children against lead poisoning. This study was undertaken to determine the current distribution of blood lead concentrations, and associated risk factors, amongst selected groups of first grade school children in the South African urban settings of Cape Town, Johannesburg 7 and Kimberley, a lead mining town (Aggeneys) and two rural towns in the Northern Cape province. A further objective of the study was to compare blood lead distributions determined in the current study with the findings of similar studies undertaken prior to the introduction in 1996 of unleaded petrol in South Africa. The results show that over the past decade, blood lead concentrations amongst first grade school children have declined considerably, but that large proportions of children, especially those living or attending school in impoverished areas, continue to have intolerably high blood lead concentrations, within a range that puts them at risk of detrimental health and social outcomes. The major sources of exposure to lead in the samples studied were leaded petrol, lead-based paint used to decorate homes and schools, lead solder used in “cottage industries” and other home-based lead-related activities, as well as the transfer of lead particles from lead-related work settings into homes. Recommendations for policy and relevant interventions for the South African context are discussed.

Orientador: Maria Cristina de Senzi Zancul / Banca: Rosa Fátima de Souza Chaloba / Banca: Luciana Maria Guarnieri / Resumo: O presente trabalho tem como objetivo estudar as contribuições dos Parâmetros Curriculares Nacionais - PCN, para as práticas pedagógicas dos professores dos anos iniciais do ensino fundamental, em escolas da rede pública de ensino, buscando identificar, na visão dos professores, possíveis modificações que vêm ocorrendo, após dez anos da elaboração e implantação desse documento. A opção metodológica foi a condução de um estudo com características das abordagens qualitativas. Os dados foram obtidos, no ano de 2009, por meio de entrevistas com dez professores, com mais de dez anos de atuação, em quatro escolas da cidade de Araraquara/SP, e pela análise dos PCN de Ciências Naturais e de documentos fornecidos por alguns dos docentes. São realizadas análises com o apoio teórico do conceito de currículo de Gimeno Sacristán (2001). Os resultados revelam que os professores conhecem os PCN e acreditam que esse referencial influencia suas práticas de Ciências Naturais. Pelas análises percebemos que essa influência se dá, muitas vezes, de forma indireta, pelo uso do livro didático, o material mais utilizado, pelos professores que fizeram parte do estudo, para a seleção e ordenação dos conteúdos e na escolha das atividades didáticas. Dada a relevância do ensino de Ciências na formação dos alunos, destacamos a importância de mais estudos que abordem as práticas pedagógicas para os anos iniciais do ensino fundamental, relacionadas a essa disciplina / Abstract: The present work aims to study the contributions of the National Curriculum Parameters (PCN) to the pedagogical practices of teachers in early grades of primary education in public schools with the view to identify possible changes that have occurred after ten years of development of this document. The method was chosen in order to conduct a study of qualitative approach. The data were obtained in 2009 through ten interviews with teachers of four public schools in the city of Araraquara / SP who have been teaching for over ten years, and also through the analysis of documents provided by some of them. The analyses were carried on based on the concept of curriculum of Gimeno Sacristán (2001). The results show that teachers are familiar with the PCN and believe that these documents influence their practice of Natural Sciences. We realized that this influence takes place, often indirectly, by the use of textbooks - the most common reference used by interviewed teachers- for the selection, ordering of content and choice of teaching activities. Knowing the importance of Natural Sciences teaching for the development of students, we highlight the importance of further studies that address the pedagogical practices for the early years of elementary school, related to this subject / Mestre

[pt] Nos últimos anos, o uso de dispositivos móveis em grades computacionais tem sido alvo de crescente investigação. Entretanto, um problema mais desafiador, referente ao estabelecimento dinâmico de grades móveis, baseadas exclusivamente em redes sem fio ad hoc, ainda tem sido pouco investigado. Uma contribuição desta tese é a proposta de uma arquitetura de software específica para grades móveis, que pode ser igualmente aplicável a redes sem fio infraestruturadas e ad hoc. Em grades fixas, a responsabilidade de prover um serviço computacional é compartilhada entre dispositivos com relativa abundância de recursos, se comparadas a grades móveis. Nestas últimas, é interessante que a descoberta e a seleção de recursos para execução de tarefas sejam tratadas conjuntamente, de modo a promover a seleção automática dos dispositivos com maior disponibilidade de recursos, considerando-se os requisitos da aplicação. Entretanto, tais elementos têm sido tradicionalmente tratados em separado na literatura relacionada a grades móveis e, em grande parte das abordagens existentes, assume-se que a seleção de recursos seja executada de forma manual pelos usuários da grade móvel. Esta tese propõe, como uma outra contribuição, um protocolo que integra as fases de descoberta e seleção automática de recursos em grades móveis, permitindo que a provisão de serviços computacionais seja escalonada entre os dispositivos com maior disponibilidade dos recursos requeridos pelo serviço. Devido à característica dinâmica dos recursos que correspondem às requisições dos usuários em uma grade móvel (por exemplo, tempo de CPU livre e memória disponível), o protocolo baseia-se unicamente no envio, sob demanda, de requisições via broadcast. No entanto, principalmente em redes sem fio ad hoc de saltos múltiplos, essa estratégia pode acarretar uma sobrecarga nos dispositivos envolvidos, tanto na difusão de requisições quanto no encaminhamento de respostas. Uma terceira contribuição desta tese é o desenvolvimento de um mecanismo que permite reduzir a sobrecarga, devido à difusão de mensagens de resposta, por meio da supressão de respostas excedentes ao longo da rede. O mecanismo, embora implementado no contexto do protocolo proposto nesta tese, pode ser aplicado também a outros protocolos de descoberta baseados no envio de requisições via broadcast. Os resultados experimentais, obtidos em redes de testes e em plataformas de simulação, mostram que o protocolo proposto provê um balanceamento de carga eficiente entre os dispositivos, mediante o aumento do número de requisições. Além disso, pode-se observar que o mecanismo de supressão de respostas é escalável no que diz respeito ao crescimento do número de dispositivos, em comparação com protocolos de descoberta baseados puramente no envio de requisições por broadcast em redes sem fio ad hoc. / [en] In the last few years, the use of mobile devices in computational grids has seen a growing interest. Nevertheless, a more challenging issue, the dynamic establishment of mobile grids on wireless ad hoc networks, has been so far only partially addressed. The first contribution of this thesis is the proposal of a software architecture for mobile grids that can be used for both infrastructured and ad hoc wireless networks. In the execution of conventional applications in grids, the responsibility to provide the service is shared among the most resourceful mobile devices. In mobile grids, it is fundamental that resource discovery and selection of resources are jointly handled. This calls for a mechanism that promotes the automatic selection of the best resource providers amongst the discovered nodes, taking into account the requirements of the application. Discovery and selection, however, have been traditionally handled separately and in most approaches the selection of resources and services requires explicit intervention by the user of the mobile grid. As a second contribution of this thesis, we propose a protocol that integrates the phases of resource discovery and automatic selection in mobile grids, allowing that computational resource provisioning is scheduled among the most resourceful nodes. Due to the dynamics of the resources needed in a mobile grid (for example, free CPU time and available memory), the protocol is based solely on demand- driven broadcasts. However, mainly in multihop ad hoc wireless networks, this strategy can incur in overhead at the involved devices, due to the diffusion of requests and replies. A third contribution of this thesis is the development of a mechanism that allows to reduce this overhead by means of the suppression of redundant replies in the network. The mechanism has been implemented in the context of the proposal protocol, but can be applied as well to other query-based discovery protocols based on broadcasts. The experimental results obtained from executions in a testbed and through simulations show that the proposed protocol provides efficient load balancing between devices with an increasing number of requests. Moreover, it can be observed that the mechanism for suppression of replies scales well with respect to an increasing number of devices when compared to other discovery protocols in wireless ad hoc networks that are purely based on requests via broadcast.

Grades computacionais oportunistas utilizam recursos ociosos de máquinas compartilhadas para executar aplicações que necessitam de um alto poder computacional e/ou trabalham com grandes quantidades de dados. Mas a execução de aplicações paralelas computacionalmente intensivas em ambientes dinâmicos e heterogêneos, como grades computacionais oportunistas, é uma tarefa difícil. Máquinas podem falhar, ficar inacessíveis ou passar de ociosas para ocupadas inesperadamente, comprometendo a execução de aplicações. Um mecanismo de tolerância a falhas que dê suporte a arquiteturas heterogêneas é um importante requisito para estes sistemas. Neste trabalho, analisamos, implementamos e avaliamos um mecanismo de tolerância a falhas baseado em checkpointing para aplicações paralelas em grades computacionais oportunistas. Este mecanismo permite o monitoramento de execuções e a migração de aplicações entre nós heterogêneos da grade. Mas além da execução, é preciso gerenciar e armazenar os dados gerados e utilizados por estas aplicações. Desejamos uma infra-estrutura de armazenamento de dados de baixo custo e que utilize o espaço livre em disco de máquinas compartilhadas da grade. Devemos utilizar somente os ciclos ociosos destas máquinas para armazenar e recuperar dados, de modo que um sistema de armazenamento distribuído que as utilize deve ser redundante e tolerante a falhas. Para resolver o problema do armazenamento de dados em grades oportunistas, projetamos, implementamos e avaliamos o middleware OppStore. Este middleware provê armazenamento distribuído e confiável de dados, que podem ser acessados de qualquer máquina da grade. As máquinas são organizadas em aglomerados, que são conectados por uma rede peer-to-peer auto-organizável e tolerante a falhas. Dados são codificados em fragmentos redundantes antes de serem armazenados, de modo que arquivos podem ser reconstruídos utilizando apenas um subconjunto destes fragmentos. Finalmente, para lidar com a heterogeneidade dos recursos, desenvolvemos uma extensão ao protocolo de roteamento em redes peer-to-peer Pastry. Esta extensão adiciona balanceamento de carga e suporte à heterogeneidade de máquinas ao protocolo Pastry. / Opportunistic computational grids use idle resources from shared machines to execute applications that need large amounts of computational power and/or deal with large amounts of data. But executing computationally intensive parallel applications in dynamic and heterogeneous environments, such as opportunistic grids, is a daunting task. Machines may fail, become inaccessible, or change from idle to occupied unexpectedly, compromising the application execution. A fault tolerance mechanism that supports heterogeneous architectures is an important requisite for such systems. In this work, we analyze, implement and evaluate a checkpointing-based fault tolerance mechanism for parallel applications running on opportunistic grids. The mechanism monitors application execution and allows the migration of applications between heterogeneous nodes of the grid. But besides application execution, it is necessary to manage data generated and used by those applications. We want a low cost data storage infrastructure that utilizes the unused disk space of grid shared machines. The system should use the machines to store and recover data only during their idle periods, requiring the system to be redundant and fault-tolerant. To solve the data storage problem in opportunistic grids, we designed, implemented and evaluated the OppStore middleware. This middleware provides reliable distributed storage for application data, which can be accessed from any machine in the grid. The machines are organized in clusters, connected by a self-organizing and fault-tolerant peer-to-peer network. During storage, data is codified into redundant fragments, allowing the reconstruction of the original file using only a subset of those fragments. Finally, to deal with resource heterogeneity, we developed an extension to the Pastry peer-to-peer routing substrate, enabling heterogeneity-aware load-balancing message routing.

Polímeros contendo grupos azo-benzênicos têm sido estudados devido a sua capacidade para óptica não linear, formação de superfícies de relevo e de birrefringência fotoinduzida. O fator que possibilita essas aplicações é a propriedade de fotoisomerização reversível trans-cis-trans do grupo azo que produz a sua reorientação molecular. Neste trabalho foram produzidos filmes casting do poliuretano MDI-DR19 derivado de azo-benzeno. Estudou-se o crescimento e decaimento da birrefringência para diferentes valores de potência da luz de excitação da fotoisomerização. Os resultados experimentais do crescimento e decaimento foram analisados usando duas exponenciais e eles mostraram que o polímero MDI-DR19 apresenta boas características para utilização em armazenamento óptico pois cerca de 65% da birrefringência induzida no material permanece por longos intervalos de tempo. Ilustramos o processo de armazenamento de informação gravando uma imagem de birrefringência num filme de MDI-DR19. Foram também produzidas grades de relevo em filmes de MDI-DR19 utilizando franjas de interferência produzidas com luz de polarização P e S. Essas grades apresentaram alta uniformidade e características compatíveis com as mostradas na literatura. / Polymers containing azobenzenic groups have been studied due to their applications on non-linear optics, surface relief gratings (SRG) and photoinduced anisotropy for optical storage. The reversal photoisomerization trans-cis-trans property of the azo group induces a molecular reorientation. In this work, cast films of na azobenzene derivative, the polyurethane MDI-DR19, were studied. The build-up and decay of the birefringence were studied as a function of the photoisomerization exciting light power. The data of the build-up and decay of the birefringence were fitted with a bi-exponential function, which shows the stability of the MDI-DR19 for application in optical storage, since 65% of the induced birefringence remains after a long time. The optical storage is illustrated by recording a birefringence image in a film of MDI-DR19. It was also performed a SRG over films of MDI-DR19 applying an interference finger pattern with a P and S polarized light. The light induced gratings shows good uniformity and characteristics compatible with those presented in the literature.