Thesis advisor: Marc L. Snapper / Intramolecular [2+2] photocycloadditions have been studied: (i) Previous studies in our group have demonstrated that there is a regiochemical dependence of intramolecular [2+2] photocycloadditions on the solvent employed. In order to understand the generality of hydrogen bonding effects of photochemical reactions of β-hydroxyl enones, we examined the photochemical outcome of enones with both acyclic and cyclic olefin tethers. (ii) An application of an intramolecular [2+2] photocycloaddition/ fragmentation strategy to form 5-8-5 ring systems has been demonstrated toward the synthesis of the natural product cycloaraneosene. / Thesis (PhD) — Boston College, 2008. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

A polimerização de monômeros vinílicos fotoiniciada por corantes foi estudada em diferentes meios (meio orgânico, ausência de solvente e meio hidrotrópico). A polimerização fotoiniciada do MMA pelo corante Vermelho Neutro na presença de trietilamina foi estudada com o objetivo de se determinar o mecanismo que leva à formação dos radicais iniciadores. Uma expressão para o rendimento de radicais livres foi deduzida a partir do mecanismo proposto, os valores experimentais para o equilíbrio e as constantes de reação para os estados fundamental, singlete e triplete do corante na presença de outras espécies e de trietilamina (co-iniciador) foram utilizadas para simular o comportamento do sistema de polimerização. A amina aromática 4-anisidina também foi utilizada como coiniciador. As cinéticas de fotopolimerização de monômeros multifuncionais foram acompanhadas com as técnicas de Fotocalorimetria Diferencial de Varredura (Foto-DSC) e Espectroscopia de Infravermelho por Transformada de Fourier em Tempo Real (RT-FTIR). Os iniciadores utilizados foram os corantes safranina e tioxantona. Os co-iniciadores usados foram as aminas TEA, TEOHA e EDB. Todos os sistemas foram estudados na ausência de solvente. Filmes poliméricos foram preparados para verificar a absorção de clorofórmio mediante a técnica de gravimetria. Tal estudo avaliou a relação entre a densidade de entrecruzamento dos polímeros e o fotoiniciador utilizado. Copolímeros de ESS e MMA ou HEMA foram preparados em meio hidrotrópico por polimerização fotoiniciada utilizando o corante catiônico safranina. A concentração de ESS utilizada foi de 0,5 M, pois nessa concentração há a formação de agregados de ESS, caracterizando o meio como hidrotrópico. As polimerizações dos monômeros MMA (hidrofóbico) e HEMA (hidrofílico) apresentaram comportamentos distintos frente ao meio hidrotrópico. / The photoinitiation of the polymerization of methyl methacrylate by the dye neutral red in the presence of thiethylamine was studied in order to determine the mechanism that leads to the formation of the initiating radicals. An expression for the yield of free radicals was deduced from the mechanism, and the experimental values for the equilibrium and reaction constants of the ground, singlet and triplet states of the dye in the presence of the other components of the formulation, were used to calculat the behaviour of the system when varying the concentration of the co-initiator triethylamine. The observed dependence fits closely the global polymerization rates obtained directly from polymerization kinetics studied by dilatometry. The amine 4-anisidine has also been used as co-initiator. The photoinitiated polymerization of multifunctional monomers was followed by real time infrared spectroscopy (RTIR) and by photo differential scanning calorimeter (Photo- DSC). Several parameters influence this kinetic such as temperature, photoinitiator concentration, light intensity, polymerizable function concentration, and material thickness. The initiators used in this study were the dyes safranine and thioxanthone. The co-initiators used were the amines TEA, TEOHA and EDB. The swelling of films of these copolymers were determined by chloroform absorption. A good inverse relationship was found between the swelling and the polymerization rates. Copolymers of styrenesulfonate and methyl methacrylate, or hydroxyethyl methacrylate, were prepared by photoinitiation polymerization using the cationic dye Safranine in hydrotropic medium. The reactions were be carried out at Stys concentrations higher than the MHC (minimum hydrotrope concentration) where the monomer forms aggregates.

O destaque alcançado por um grupo significativo de cidades do interior do estado de São Paulo, que nas últimas décadas só foi mais reforçado pelo dinamismo econômico, evidenciou os aspectos que as projetam como pólos regionais. Nesse grupo de cidades ressalta-se a extrema urbanização, em muitas delas uma avançada conurbação com as vizinhas. Surgem aglomerações, que vão de 500 mil a mais de dois milhões de habitantes, formando uma rede de cidades que lideram o segundo maior mercado consumidor brasileiro. A atividade industrial crescente, a geração de empregos, o conseqüente crescimento demográfico e o espraiamento urbano, deram a essas cidades características de organização espacial muito própria e um sistema viário que não acompanhou esse crescimento, mais expressivo do que os das grandes capitais. Contudo, um elemento está presente em todas essas cidades e constitui um rico patrimônio histórico e, talvez, estratégico em seus futuros: a ferrovia. Nas dez maiores cidades do interior paulista, a presença marcante da velha estação e da linha férrea, que as cruzam e as dividem, são as heranças do processo de desmantelamento e total abandono da função ferroviária de transporte de passageiros de longo percurso. Quase sempre relegadas a funções acessórias no planejamento urbano, a ferrovia também esteve distante, encerrada entre seus muros, mantendo o diálogo com as cidades embaraçado ao longo do tempo. Essa pesquisa se propôs a fazer um levantamento geral desses patrimônios ferroviários, identificar suas interfaces atuais com o meio urbano, os novos agentes envolvidos na sua exploração e, principalmente, a visão e os usos pretendidos pelos municípios para as faixas ferroviárias e suas áreas lindeiras. Buscando amparo nas evoluções históricas, na análise de influências recíprocas e nas relações entre transporte e urbanismo, questiona-se a presença dos trilhos nessas áreas intensamente urbanizadas e são expostas as relações institucionais que devem ser consideradas para planejar e viabilizar o seu aproveitamento, seja pela implantação de novos equipamentos urbanos, pelo uso compartilhado de transportes ou mesmo pela sua erradicação. / A large number of relevant cities in the countryside of São Paulo state has recently faced a remarkable distinction brought by a high economical dinamism in these regional poles during the last decades. These cities already have extreme urbanization rates and they are getting aglomerated, creating new metropolitan areas, with a huge population that is responsible for Brazil´s second largest consuming market. The increasing industrial activity and the offers of new jobs have both stimulated the spreading of its urbanized areas that are not always followed by enough new transportation infra structures. However, one element is very present in any of these cities and it stands for rich historical assets: the old railway. Inside any medium size São Paulo´s city in, the prominent station and the rail tracks still divide the urban center, instersecting its streets and being source of many conflicts and accidents. Nowadays, those abandoned structures are the inheritahe of passenger rail transportation, which was completely dismantled after freight rail transports privatizations. Specially inside the cities, not only the railways were continualy limited to secondary functions in all urban planning process, but the urban transportation was never taken as a priority for rail administration either. This research aimed to build a general view of railway equipments and structures of ten cities, identify possible interfaces with their urban areas, identify the agents envolved in its exploitation and mainly identify what the local expectations to the railways are. The analysis was done based on historical evolution of railways and cities, by the influence of transportation infra structure on territories. Urbanism and public transport organization notions were considered as well, in order to identify the needs and ways on what kind of railway would contribute or would be more profitable in new urban functions.

Na tentativa de estudar a viabilidade do sistema KCl:KCN:OCN-: Eu+2 como meio ativo para laser sintonizável na região do infravermelho médio, observou-se uma interessante característica deste sistema na região do visível. Os íons Eu+2 em sítios acoplados aos íons moleculares CN- e OCN- apresentam uma forte luminescência na região do verde (banda larga centrada em 505nm à temperatura ambiente), cuja característica possibilita um estudo posterior da emissão laser deste sistema. Neste trabalho estuda-se a transição 4f7 4f65d de íons Eu+2 por processo de absorção de um fóton, utilizando as técnicas de absorção ótica, luminescência e medição de tempo de vida. Estuda-se, também, a transição 4f7 4f7 (8S7/2 6P7/2) por processo de absorção de dois fótons. Para o estudo da interação entre os íons Eu+2 e íons moleculares CN- foram feitos tratamentos térmicos à diferentes temperaturas, na tentativa de tornar eficaz o aclopamento eletrônico-vibracional, devido à mobilidade que os íons Eu+2 apresentam na rede cristalina. Toda a parte de aquisição de dados é realizada por um sistema, desenvolvido no próprio Grupo de Ótica, acoplado ao microcomputador. / In the attempt to study the feasibility of the KCl:KCN:OCN-: Eu+2 system as an active medium for mid-infrared tunable lasers, it was observed an interesting feature of this system in the visible region. The Eu+2 ions in the site coupled to CN- and OCN- molecular ions exhibit a strong luminescence in the green region (a large band centered in 505 nm at room temperature). This feature makes possible a further study of the laser action in this system. In this work the 4f7 4f65d transition of Eu+2 ions is studied by means of one photon absorption process, using optical absorption, luminescence and lifetime measurement techniques. The 4f7 4f7 (8S7/2 6P7/2) transition of Eu+2 ions is studied by two photon absorption. In order to study the Eu+2 CN- interaction, the samples were annealed at different temperatures, aiming to obtain an effective electronic-vibrational coupling, due the mobility the Eu+2 ions exhibit in the lattice. The data acquisition is achieved by a system coupled to microcomputer.

An approach to education gaining popularity in the modern classroom, adaptive tutoring systems offer interactive learning environments in which students can access immediate feedback and rich tutoring while teachers can achieve organized assessment for targeted interventions. Yet despite the benefits that these systems provide, a number of questions remain regarding the optimal inner workings of adaptive platforms. What is the recipe for optimal student performance within these platforms? What elements should be taken into consideration when designing these learning environments? Can facets of these platforms be harnessed to increase students’ motivation to learn and to improve both immediate and robust learning gains? This thesis combines work conducted over the past two years through versatile approaches toward the goal of enhancing student motivation and learning within the ASSISTments platform. Approaches considered include a) enhancing motivation and performance through altered feedback using hypermedia elements, b) instilling motivational messages alongside media enhanced content and feedback, c) allowing students to choose their feedback medium, thereby exerting control over their assignment, d) altering content delivery by interleaving skills to enhance solution strategy development, and e) establishing partial credit assessments to drive motivation and proper system usage while enhancing student modeling. After a brief introduction regarding the main tenants of this research, each chapter highlights a randomized controlled trial focused around one of these approaches. All studies presented have been conducted or are still running within ASSISTments. Much of this work has already been published at peer reviewed conference venues, some with stringent acceptance rates as low as 25% for full papers. Two of the studies presented here are second iterations of previously published work that are still in progress, and only preliminary analyses are available. A chapter on conclusions and future work is included to discuss the contributions that have been made to the Learning Sciences community thus far, and to briefly discuss potential directions for my continued research.

An approach to education gaining popularity in the modern classroom, adaptive tutoring systems offer interactive learning environments in which students can access immediate feedback and rich tutoring while teachers can achieve organized assessment for targeted interventions. Yet despite the benefits that these systems provide, a number of questions remain regarding the optimal inner workings of adaptive platforms. What is the recipe for optimal student performance within these platforms? What elements should be taken into consideration when designing these learning environments? Can facets of these platforms be harnessed to increase students’ motivation to learn and to improve both immediate and robust learning gains? This thesis combines work conducted over the past two years through versatile approaches toward the goal of enhancing student motivation and learning within the ASSISTments platform. Approaches considered include a) enhancing motivation and performance through altered feedback using hypermedia elements, b) instilling motivational messages alongside media enhanced content and feedback, c) allowing students to choose their feedback medium, thereby exerting control over their assignment, d) altering content delivery by interleaving skills to enhance solution strategy development, and e) establishing partial credit assessments to drive motivation and proper system usage while enhancing student modeling. After a brief introduction regarding the main tenants of this research, each chapter highlights a randomized controlled trial focused around one of these approaches. All studies presented have been conducted or are still running within ASSISTments. Much of this work has already been published at peer reviewed conference venues, some with stringent acceptance rates as low as 25% for full papers. Two of the studies presented here are second iterations of previously published work that are still in progress, and only preliminary analyses are available. A chapter on conclusions and future work is included to discuss the contributions that have been made to the Learning Sciences community thus far, and to briefly discuss potential directions for my continued research.

Digitized by Kansas Correctional Industries

In the four decades since Stanley Cohen (1972) first theorised the ‘moral panic’, there has been immense technological change in the field of communications and media. Whilst Cohen’s original model relies on elite-driven mediated narratives, I argue that moral panics have taken on a memetic quality in the convergent and participatory mediascape. In other words: in an age of social media, moral panic discourses are increasingly open to contestation, reinterpretation, and recirculation by multiple actors and groups. In this thesis, I examine one such group – the web’s largest white nationalist (WN) forum, Stormfront. To do so, I trace three racialized media events as they circulate on and through the Forum. Here, I show how the mechanics of the moral panic have fundamentally shifted in the digital age. I explore the means by which Stormfront users exploit this semi-democratised mediascape in an attempt to ‘manage’ and exploit moral panics surrounding episodes of racialized violence. To this end, I explore the topologically entangled shuttling back and forth of ‘online’ and ‘offline’ lives and spaces to argue for a more-than-digital geography of computer mediated communication. Here, I show how the Forum’s ‘collective voice’ is often given expression through selective quotation by mainstream media surrounding racialized moral panics. This process of remediation, I argue, allows explicitly racist groups fugitive access to mainstream discourse, and turns mainstream media outlets into unwitting nodes in a white nationalist broadcast network. However, I argue that this public-facing process, opens WNs up to increased scrutiny, leading to strategic and contingent deployments of contradictory repertoires of race. In doing so, I examine repertoires of race in such WN interventions - highlighting their flexible and contingent construction of racialized categories in the negotiation of contemporary structures of feeling (Williams 1977; Anderson 2014). I contend that a digitally-inflected antiracism must attend to the contingent, translocal, and assembled nature of racism online if it is to be effective.

Magister Scientiae Dentium - MSc(Dent) / Introduction: Dental caries has one the highest incidences in children and the host’s diet may be a major factor in determining susceptibility to the disease. A proposed tool to screen and identify high risk individuals uses a bitter compound 6-n-propylthiouracil (PROP). The goal of this screening tool is to identify mothers and children who are Non-tasters (those who cannot taste PROP) and to educate them about their possible affinity towards sugar substances and its harmful effects on oral and general health. It is suggested that Non-taster children could be prioritized when providing preventative dental treatment. Aim: To validate the use of PROP as a screening tool for determining high caries risk individuals by identifying the taster status of mothers and children, their preference towards sugar, and its impact on their caries status. Methodology: 75 mother/ child pairs were recruited to participate in this study. Caries experience, sugar preference and taster status were determined for all the subjects. Comparisons were made between mothers and their children to find a possible association. Results: Caries experience was greater in individuals who were Non-tasters when compared to Super-tasters. A significant association between taster status and DMFT score was established (p<0.000). A significant association between taster status and sugar preference was established (p<0.000). A positive correlation with regard to taster status, sugar preference and caries experience was observed in mother/child pairs. Conclusion: Similarities in the mother's and child’s PROP taster status and its association with sugar preference allows such a screening test to identify individuals who are at high risk of developing dental caries. Early identification of mothers who are Non-tasters may allow the introduction of early intervention strategies and assist in the early detection of potentially high-risk children, especially in environments where resources are limited.

The research is focusing on small and mid-sized enterprises (SMEs) in the German Medical Technology (MedTech) industry and investigates the antecedents and the effects of organizational capabilities on their strategy regarding international ventures. Although there is various research in the field of strategy, internationalisation and SMEs, the impact of existing research in the specific field of German Medtech SMEs is relatively poor while theoretical and empirical findings obtained in another particular institutional context are not yet applicable in other countries or industries. As a consequence, a systematic review of the literature has been conducted. An initial conceptual model was developed, in which significant findings regards country, industry and firm-specific aspects could be identified. The philosophical stand of the researcher and his ontological view as a post-positivist allows both, a qualitative and a quantitative approach. By applying a mixed method approach a focus group discussion provided in depth-knowledge in order to sharpen the initial model. Antecedents, as well as the most important factors related to strategy, were emphasized and further important aspects that focus on capabilities were revealed. With these results, constructs and relationships were modeled and quantitative data from a survey with more than 60 German MedTech SMEs were collected and assessed. This approach led to the finding that factors such as ́market potential ́, ́physical capital ́, ́medical regulations ́ and ́product competitive-ness ́ have the highest influence on the firm ́s strategic approach. ́Organizational learning ́ and ́coordination mechanism ́ have particularly an impact on strategy development, whereas relationship capabilities mediating effect on the strategy-competitive advantage relationship. Firm size and firm ́s experience in international ventures influence a firm ́s internationalisation. The results will serve as a strategic input for SME’s in the German MedTech industry. This research provided a contribution to knowledge that is relevant from an academic as well as from an economic point of view. The findings should help academics, MedTech SMEs, and governmental institutions to understand the decisive factors for internationalisation and the importance to develop specific organizational capabilities in this context. This understanding contributes towards a sound development of German MedTech SMEs in their future internationalisation.