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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

A dim view of M-cone onsets

Parry, Neil R.A., McKeefry, Declan J., Kremers, Jan, Murray, I.J. 03 1900 (has links)
No / We investigated the brightness (i.e., perceived luminance) of isolated L- and M-cone pulses to seek a perceptual correlate of our previous reports that M-on electroretinograms resemble L-off responses, implying the operation of post-receptoral opponent processing. Using triple silent substitutions, cone increments were generated in a 4-primary ganzfeld, masked by random positive or negative luminance bias. The results show that M-cone increments decrease in brightness, while L-cone increments increase. These differences became smaller as field size reduced; this was not eccentricity or area dependent. We speculate about early retinal input into brightness perception.
62

Effect of high-fat diet on isometric, concentric and eccentric contractile performance of skeletal muscle isolated from female CD-1 mice

Tallis, J., James, Rob S., Eyre, E.L.J., Shelley, S.P., Hill, C., Renshaw, D., Hurst, J. 25 July 2024 (has links)
Yes / Despite evidence inferring muscle and contractile mode-specific effects of high-fat diet (HFD), no study has yet considered the impact of HFD directly on eccentric muscle function. The present work uniquely examined the effect of 20-week HFD on the isometric, concentric and eccentric muscle function of isolated mouse soleus (SOL) and extensor digitorum longus (EDL) muscles. CD-1 female mice were randomly split into a control (n = 16) or HFD (n = 17) group and for 20 weeks consumed standard lab chow or HFD. Following this period, SOL and EDL muscles were isolated and assessments of maximal isometric force and concentric work loop (WL) power were performed. Each muscle was then subjected to either multiple concentric or eccentric WL activations. Post-fatigue recovery, as an indicator of incurred damage, was measured via assessment of concentric WL power. In the EDL, absolute concentric power and concentric power normalised to muscle mass were reduced in the HFD group (P < 0.038). HFD resulted in faster concentric fatigue and reduced eccentric activity-induced muscle damage (P < 0.05). For the SOL, maximal isometric force was increased, and maximal eccentric power normalised to muscle mass and concentric fatigue were reduced in the HFD group (P < 0.05). HFD effects on eccentric muscle function are muscle-specific and have little relationship with changes in isometric or concentric function. HFD has the potential to negatively affect the intrinsic concentric and eccentric power-producing capacity of skeletal muscle, but a lack of a within-muscle uniform response indicates disparate mechanisms of action which require further investigation.
63

Improved estimation of pore connectivity and permeability in deepwater carbonates with the construction of multi-layer static and dynamic petrophysical models

Ferreira, Elton Luiz Diniz 09 October 2014 (has links)
A new method is presented here for petrophysical interpretation of heterogeneous carbonates using well logs and core data. Developing this new method was necessary because conventional evaluation methods tend to yield inaccurate predictions of pore connectivity and permeability in the studied field. Difficulties in the petrophysical evaluation of this field are related to shoulder-bed effects, presence of non-connected porosity, rock layers that are thinner than the vertical resolution of well-logging tools, and the effect of oil-base mud (OBM) invasion in the measurements. These problems give rise to uncommon measurements and rock properties, such as: (a) reservoir units contained within thinly bedded and laminated sequences, (b) very high apparent resistivity readings in the oil-bearing zone, (c) separation of apparent resistivity logs with different depths of investigation, (d) complex unimodal and bimodal transverse relaxation distributions of nuclear magnetic resonance (NMR) measurements, (e) reservoir units having total porosity of 0.02 to 0.26 and permeability between 0.001mD to 4.2D, (f) significant differences between total and sonic porosity, and (g) low and constant gamma-ray values. The interpretation method introduced in this thesis is based on the detection of layer boundaries and rock types from high-resolution well logs and on the estimation of layer-by-layer properties using numerical simulation of resistivity, nuclear, and NMR logs. Layer properties were iteratively adjusted until the available well logs were reproduced by numerical simulations. This method honors the reservoir geology and physics of the measurements while adjusting the layer properties; it reduces shoulder-bed effects on well logs, especially across thinly bedded and laminated sequences, thereby yielding improved estimates of interconnected porosity and permeability in rocks that have null mobile water saturation and that were invaded with OBM. Additionally, dynamic simulations of OBM invasion in free-water depth intervals were necessary to estimate permeability. It is found that NMR transverse relaxation measurements are effective for determining rock and fluid properties but are unreliable in the accurate calculation of porosity and permeability in thinly bedded and highly laminated depth sections. In addition, this thesis shows that low resistivity values are associated with the presence of microporosity, and high resistivity values are associated with the presence of interconnected and vuggy porosity. In some layers, a fraction of the vuggy porosity is associated with isolated pores, which does not contribute to fluid flow. An integrated evaluation using multiple measurements, including sonic logs, is therefore necessary to detect isolated porosity. After the correction and simulation, results show, on average, a 34% improvement between estimated and core-measured permeability. Closer agreement was not possible because of limitations in tool resolution and difficulty in obtaining a precise depth match between core and well-log measurements. / text
64

The Influence of Isolated and Integrated Fourth Grade Music on Children's Achievements in Music and Academic Subjects

Phillips, Ena Melba 08 1900 (has links)
The purpose of this study was to compare two types of teaching music, isolated and integrative, to determine their influence on achievements in music and academic subjects of pupils in two fourth-grade classes in a Fort Worth elementary school. Attention was directed to the values of music in the lives of individuals, to the two types of teaching music, and to the outcomes of instruction from both types of programs.
65

Divergent Roles of PI3K and Akt in Rapamycin-induced Cardioprotection against Ischemia-Reperfusion Injury

Desai, Shivani Kirit 01 January 2007 (has links)
Coronary heart disease (CHD) is one of the leading causes of death every year with nearly three-fourths of all deaths caused by the disease. The challenge scientists are facing today is discovering new drugs to protect the heart against cellular damage caused by ischemia-reperfusion injury (I-R injury). Rapamycin is one such drug that has been shown to protect the heart against ischemia-induced cellular injury. Rapamycin(sirolimus) inhibits protein synthesis through inhibition of the mammalian target ofrapamycin (mTOR). This property of rapamycin has led to its current clinical applications in drug-eluting stents and in immunosuppresive treatment to organ transplant patients. The mechanism by which this drug protects against I-R injury is currently unknown. The goal of this study is to elucidate rapamycin's cardioprotective signaling pathway. We hypothesized that upregulation of Akt occurs possibly as part of a positive feedback mechanism following the inhibition of mTOR by rapamycin. Adult male ICRmice were treated with rapamycin (0.25 mg/kg, i.p.), or volume-matched DMSO (solvent for rapamycin), or rapamycin (0.25mg/kg, i.p.) plus wortmannin (WTN, 15µg/kg, i.p.),an inhibitor of phosphatidylinositol 3-kinase, or wortmannin alone (15µg/kg, i.p.). After 30 min of stabilization, the hearts were subjected to 20 minutes of global ischemia and 30 minutes of reperfusion in Langendorff model. In a separate series of experiments mice were either injected with DMSO or rapamycin for 30 minutes, 1 hour, and 2 hours before harvesting the hearts for Western blot analysis of levels of total or phosphorylated Akt at Ser473. Our results showed that rapamycin protected the heart as observed by a reductionin infarct size from 33.8 ± 2.0% in DMSO-treated hearts to 19.3 ± 4.1% in rapamycin-treated hearts; a 43% reduction. This infarct-limiting effect was completely blocked by wortmannin (29.3 ± 4.8%). However, Western blot analysis showed no change in the level of Akt phosphorylation after administration of rapamycin. Our current resultsfurther confirmed rapamycin as a potential cardio-therapeutic drug to limit infarct size,potentially through the PI3K signaling pathway. However, the exact signaling pathway of this protection still remains elusive.
66

Conversores DC-DC Dual-Active-Bridge isolados bidirecionais. / Isolated bidirectional dual active bridge DC-DC converter.

Enomoto, Bruno Yukio 28 March 2018 (has links)
Este trabalho visa o estudo das regiões de operação de conversores CC/CC isolados bidirecionais do tipo DAB (Dual Active Bridge). É feito um estudo do comportamento do circuito com a variação dos valores das reatâncias de acoplamento, avaliando-se aspectos como eficiência, fator de potência, reativos, entre outros. A seguir é proposta uma estrutura de controle que permite a operação com tensões nos barramentos DC diferentes das nominais, minimizando as correntes absorvidas. Além disso, propõe-se uma estratégia de controle para regular a potência transferida. O trabalho inclui modelagem teórica, implementação em simulação computacional e medidas em protótipo experimental. / This work investigates operation regions of Dual Active Bridge DC-DC isolated bidirectional converters, studying circuit behavior with the variation of the coupling reactance, evaluating parameters like efficiency, power factor, reactive flow etc. A control structure is proposed which allows operating with DC voltages different from nominal voltages, reducing the AC currents. Furthermore, a control strategy to regulate the power transferred is proposed. Methodology includes theoretical modeling, computer simulation and experimental prototype measurements.
67

A escola isolada à meia-luz (1891/1927) / The school for isolated half-light (1891/1927).

Reis, Rosinete Maria dos 27 June 2011 (has links)
A presente tese se insere na Área de História e Historiografia da Educação e objetiva analisar e compreender o processo de constituição das Escolas Isoladas enquanto modalidade escolar no contexto Mato-Grossense no período de 1890-1928. Trata-se de rehistoricizar o objeto escola de (des) naturalizá-la, retratá-la em seus aspectos internos, definindo sua cultura e os processos que configuram a sua modelização e organização. A busca pela compreensão dos aspectos internos da escola isolada, ou seja, como se dava a construção social e cultural das instituições escolares, exigiu o entendimento daquilo que chamamos de cultura escolar. Na medida em que a cultura escolar se constitui numa apropriada ferramenta teórica para explorar o passado e o presente da escola na sua relação com a sociedade e a cultura, e permite explorar o jogo tenso das lutas e tensões que perpassam a escola e expressam as contradições sociais. Como instrumentos de pesquisa, utilizei de documentos oriundos de atividades funcionais e pedagógicas, como: Mensagens governamentais, Relatórios dos inspetores (diretores, após 1880) da instrução; e de Diretores dos Grupos Escolares, alguns números de Jornais, Livros de Matrículas, Ofícios, Circulares, Livros de Notas, Atas de Exames, Mapas de freqüência de alunos e professores, Provas e Exercícios Escolares, Regulamentos, Regimentos e Fotografias. Essas fontes além de oferecerem preciosas informações sobre o funcionamento da escola ainda permitiu-me visualizar as representações dos profissionais envolvidos no processo, a forma pelas quais diretores, inspetores e autoridades do ensino interpretaram e cumpriram as determinações impostas pelas novas concepções pedagógicas. Nessa trilha a educação e a instrução da população estavam sendo amplamente discutidas e reafirmadas como essenciais, a fim de tornar o país, moderno e civilizado. Tais discursos tinham clara intenção em mostrar que, somente através da organização da instrução pública, seria possível elevar o país ao nível das nações civilizadas. Organizar a instrução era, segundo eles, romper com uma estrutura ineficaz, baseada em métodos ultrapassados e dispendiosos e, sobretudo, formar devidamente os professores. A partir de então, os Regulamentos e as Reformas da instrução pública teriam a finalidade de reordenar e restabelecer os critérios para a reorganização da instrução e também para o ingresso e a permanência dos professores no magistério primário. Propósito nosso foi demonstrar que se delineou nas escolas isoladas, a constituição e articulação de uma cultura e de uma forma escolar própria, caracterizada por dispositivos de normatização pedagógica e práticas dos agentes que se apropriaram deles, por meio de estratégias e táticas reveladoras de saberes socialmente acumulados permitindo reconstruir uma identidade escolar e difundir os seus valores e comportamentos específicos. / This thesis falls within the Area of History and Historiography of Education and aims to analyze and understand the constitution of Isolated Schools as a school sport in the context of Mato Grosso in the period 1890-1928. It is the object rehistoricizar school (un) naturalizing it, portray it in its internal aspects, defining its culture and processes that shape modeling and organization. The search for understanding of the internal aspects of the school alone, that is, how was the social and cultural construction of educational institutions, demanded an understanding of what we call school culture. To the extent that the school culture is an appropriate theoretical tool to explore the past and present school in its relationship with society and culture, and the game lets you explore the tense struggles and tensions that pervade the school and express the social contradictions. As research tools, used documents from the functional and educational activities, such as government posts, the inspectors\' reports (directors, after 1880) Education, and Directors of School Groups, some numbers of Journals, Books Enrollment, Crafts, Circulars, Books, Notes, Minutes of Examinations, frequency maps for students and teachers, tests and exercises School, Regulations, Regiments and Photographs. These sources also provide valuable information about the school run has allowed me to see the representations of the professionals involved in the process, the way in which directors, inspectors and education authorities have interpreted and complied with the determinations imposed by the new educational ideas. That track the education and instruction of the population were being widely discussed and reaffirmed as essential in order to make the country, modern and civilized. Such speeches were clearly intent on showing that only through the organization of public instruction; the country could raise the level of civilized nations. Arrange the statement was, according to them, breaking with an ineffective structure, based on outdated methods and expensive and, above all, to properly train teachers. Since then, Regulations and Reforms of public education would have the purpose of reorganizing and re-establish criteria for the reorganization of education and also for entry and retention of teachers in primary teaching. Our purpose was to demonstrate that takes place in isolated schools, the creation and articulation of a culture and a school form itself, characterized by devices pedagogical norms and practices of the agents who took them through strategies and tactics that reveal knowledge socially allowing accumulated rebuild a school identity and spread its values and behaviors.
68

Serras da desordem, Corumbiara e a memória

Lopes, Fabiana Ferreira 05 September 2013 (has links)
Esta dissertação analisa os filmes Serras da desordem (2006) de Andrea Tonacci e Corumbiara (2009) de Vincent Carelli a partir da perspectiva da construção de uma memória dos vencidos. Esses filmes tratam de casos de massacres cometidos contra indígenas brasileiros em situação de isolamento, que, a pesar de terem sido amplamente divulgados na imprensa, nunca foram apurados e os culpados jamais foram condenados judicialmente. O objetivo desta pesquisa é o de compreender as estratégias utilizadas por cada um dos realizadores na reconstituição do passado e no estabelecimento no presente da memória dos grupos retratados nesses filmes. O conceito de memória usado nesta dissertação tem base nos estudos de Maurice Halbwachs. Sua aplicação nesta pesquisa demonstrou que a reconstituição do passado traz à tona a memória daqueles que historicamente vem sendo silenciados pela cultura hegemônica e letrada. Apesar da aproximação desses filmes do ponto de vista temático, a reconstituição do passado se dá de maneira distinta em cada um deles. Em Serras da desordem, Andrea Tonacci utiliza principalmente o procedimento da reencenação no presente dos episódios relacionados ao massacre por aqueles que vivenciaram essa história. Enquanto que em Corumbiara, Vincent Carelli utiliza o testemunho daqueles que sobreviveram aos massacres e dos que vivenciaram as consequências dos atentados como o principal recurso de rememoração. / The present thesis analyzes the films The Hills of Disorder (2006) by Andrea Tonacci and Corumbiara -­- they shoot Indians, don\'t they? (2009) by Vincent Carelli, and its based on memories of those who were vanquished. Both films deal with cases of massacres that were perpetrated against Brazilian Indians living in an isolated situation; cases that, although widely publicized by the press, were never investigated, and their perpetrators were never convicted in Court legally sentenced. The aim of this study is to understand the strategies that are used by each of these two filmmakers in order to reconstruct the past and to establish, in the present, the memory of the groups who are portrayed in their films. The concept of memory used in this paper is based on Maurice Halbwachs\'s studies. Its application to the present study has shown that a reconstruction of the past elicits the memory of those who have been historically silenced by hegemonic, literate culture. Even though these films are related as regards their theme, the reconstruction of the past takes place distinctly in each of them. In The Hills of Disorder, Andrea Tonacci mainly uses the procedure of a present-­-time reenactment of the events concerning the massacre, by those who have experienced the story. In Corumbiara, by contrast, Vincent Carelli uses the testimonies of those who have survived the massacres and those who have experienced the consequences of the attacks as his main resource for remembrance.
69

Conception de convertisseurs de puissance DC-DC isolés pour l'avion plus électrique / Design of isolated DC-DC power converters for more electric aircraft

Brunello, Julien 19 November 2015 (has links)
L'avion plus électrique est un concept qui a le vent en poupe chez les principaux constructeurs du domaine de l'aéronautique. Dans ce domaine, comme dans d'autres, les besoins en énergie électrique sont croissants et nécessitent de mettre en place des systèmes de conversion d'énergie fiables, performants et modulaires. Ces systèmes de conversion sont souvent couplés avec des systèmes de stockage d'énergie (type batterie) permettant dans certaines situations de rendre l'avion énergétiquement autonome grâce à une source de puissance indépendante des principaux organes de production d'énergie. Cette interconnexion batterie - réseau de bord présente un rapport de tension élevé ce qui, ajouté aux fortes valeurs de courant de la basse tension, en fait un objet particulièrement complexe à réaliser.L'objectif de cette thèse est de concevoir de manière optimale un convertisseur de puissance isolé permettant l'interconnexion d'un bus basse tension 28 V (typiquement des batteries) à un bus haute tension 540 V (réseau de bord de l'avion) avec une puissance échangeable d'environ 12 kW. Elle se déroule dans le cadre d'un projet ANR (quatre partenaires universitaires, associés à l'entreprise AIRBUS) dont l'une des tâches est le développement d'outils de conception pour l'électronique de puissance. Le travail correspondant comprend une contribution à cette tâche sous forme de la construction de modèles des principaux composants intervenant dans un convertisseur, modèles destinés à être intégrés dans les routines d'optimisation. Pour cette raison, ils seront analytiques (physique, empiriques, mélange des deux).Ces modèles seront ensuite insérés dans un outil global développé dans une autre thèse du projet, à l'aide duquel différentes architectures de convertisseurs seront comparées afin d'en déduire la meilleure solution pour le cahier des charges énoncé précédemment. Un prototype du convertisseur retenu sera finalement réalisé en utilisant des technologies avancées, pour conduire une validation expérimentale. / The electric aircraft tends to become widespread at all the main manufacturers of the domain of the aeronautics. Needs do not stop growing and require setting up reliable, efficiency and modular systems of conversion of energy. These systems of conversion are often coupled with systems of storage of energy (battery) allowing in certain situations to make the punctually autonomous aircraft energetically thanks to a source of power independent from main organs of power production. This interconnection battery - network of edge presents a very high report of rise of tension what, added to the high current value of the battery bus, in fact a particularly complex object to be realized.The objective of this thesis is to design in an optimal way a converter of power isolated allowing the interconnection of a low-voltage bus 28V (typically batteries) in a high-voltage bus 540V (network of edge of the aircraft) with an exchangeable power about 12 kW. It takes place within the framework of an ANR project (four university partners + AIRBUS) the development of tools of conception of which one of the tasks is for the ENP. The corresponding work includes a contribution to this task in the form of the construction of models of the main components occurring in a converter, model intended to be integrated into the routines of optimization. For that reason, they will be analytical (physical, empirical or mix both).These models will then be inserted into a global tool developed in another thesis of the project, by means of which various architectures of converters will be compared to deduct the best solution from it for the previous specifications. A prototype of the reserved converter will be finally realized by using advanced technologies, to lead an experimental validation.
70

Perda de inserção periodontal em uma população isolada brasileira: prevalência, extensão, severidade e indicadores de risco / Periodontal attachment loss in an untreated isolated population of Brazil: prevalence, extent, severity and risk indicators

Priscila Corraini 08 August 2007 (has links)
Os objetivos deste estudo são avaliar a prevalência, extensão e severidade de perda clínica de inserção (NCI); e investigar as possíveis associações entre variáveis demográficas, socioeconômicas e comportamentais com NCI em uma população isolada brasileira. MATERIAL E MÉTODO: Todos os indivíduos com mais de 12 anos de idade foram identificados por um censo. Eles foram entrevistados por meio de um questionário estruturado e submetidos a um exame clínico completo que consistiu na avaliação de 6 sítios por dente em toda a boca. RESULTADOS: Dentre os 214 indivíduos que foram entrevistados e receberam exame clínico completo, NCI >= 5mm foi observado em 8%, 37%, 70%, 83% e 100% dos indivíduos dentados nas faixas etárias de 12-19, 20-29, 30- 39, 40-49 e 50 ou mais anos de idade; enquanto que a prevalência de NCI >= 7mm foi de 5%, 8%, 20%, 67% e 83% nas faixas anteriormente descritas, respectivamente. Análises de regressão logística multivariável identificaram quantidade de placa visível (OR = 2,8), quantidade de cálculo supra-gengival (20-50%, OR = 2,9; e > 50%, OR= 10,6), idade (OR = 11,4) e tabagismo (OR = 2,4) como indicadores de risco para NCI >= 5mm; e tabagismo (OR = 8,2) para NCI >= 7mm. CONCLUSÃO: Os resultados demonstraram que perda clínica de inserção é altamente prevalente nesta população isolada. A alta prevalência de NCI em faixas etárias jovens e a identificação de indicadores de risco tradicionais para NCI nesta população sugerem que fatores microbiológicos ou a susceptibilidade para a exposição de fatores ambientais possam ser considerados fatores-chave para a alta ocorrência encontrada nesta população. / The aim of this study was to assess the prevalence, extent and severity of clinical attachment loss (CAL); and to investigate the associations between demographic, socioeconomic and behavioral risk indicators with CAL in an untreated isolated population in Brazil. METHODS: All subjects aged 12 years forward were selected by a census. They were submitted to a full-mouth clinical examination of six sites per tooth and were interviewed using a structured written questionnaire. RESULTS: Among the 214 subjects who were interviewed and clinical examined, CAL >= 5mm was observed in 8%, 37%, 70%, 83%, and 100% of the dentate subjects, depending on age; while the age dependent prevalence of CAL >= 7mm was 5%, 8% 20%, 67% and 83%, respectively. Multivariate analysis identified amount of plaque (OR=2.8), thresholds of supragingival calculus (OR=2.9-10.6), age (OR=11.4) and smoking (OR=2.4) as risk indicators for CAL >= 5mm, and smoking (OR=8.2) for CAL >= 7mm. CONCLUSION: The results demonstrate that CAL is highly prevalent in this isolated population. The high prevalence of CAL in young age groups and the observation of traditional risk indicators for CAL in this population suggest microbiological factors or host susceptibility to be key factors explaining the high levels of CAL found in this population.

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