When we interpret the input vector of a Boolean function as a binary number, we define interval Boolean function fn [a,b] so that fn [a,b](x) = 1 if and only if a ≤ x ≤ b. Disjunctive normal form is a common way of representing Boolean functions. Minimization of DNF representation of an interval Boolean function can be per- formed in linear time. The natural generalization to k-interval functions seems to be significantly harder to tackle. In this thesis, we discuss the difficulties with finding an optimal solution and introduce a 2k-approximation algorithm.

The East Shetland Basin is a superb natural laboratory in which to study the role that normal fault growth and linkage has in determining petroleum prospectivity. Use of several high density 3D seismic volumes and over 250 boreholes permits key aspects of the Late Jurassic rift and its Permo-Triassic precursor to be analysed and its role on hydrocarbon trap formation, reservoir distribution and migration determined. The regional interpretation has revealed the generation of a North Sea archipelago of Upper Jurassic islands, the role of relay ramps in controlling syn-rift sediment dispersal patterns and the impact of normal faults of the later episode crossing and offsetting those generated by the earlier phase. The uplift, erosion and meteoric flushing of Upper Jurassic and older strata within the exposed fault blocks could potentially have huge consequences for the Brent play by enhancing reservoir properties and hence, help identify new play opportunities down-dip of major structures. Fault control on sediment dispersal can also be documented in a more localized study on the Cladhan Field, the site of a pronounced basin-margin relay ramp. This recent discovered set of syn-rift density flows illustrates how the development and distribution of depositional gradients and transport pathways form subtle play types. The Cladhan area is just one of several locations throughout the East Shetland Basin where the interaction of multiple rift phases is influential in the structural feedback after the Upper Jurassic rifting event. The delicate interaction and reactivation of underlying structural trends creates a series of multi-tiered fault block systems which can define several aspects of a petroleum system, depending upon the strike, polarity and level of reactivation of faults from one rift to another. The observations of fault growth and linkage in the Northern North Sea may provide generic lessons that help in determining petroleum prospectivity in other hydrocarbon rift basins (e.g. E. Africa and the N. Atlantic seaboard of North America).

Les conditions de déplacement de l'huile en géométries simples sont étudies en fonction des caractéristiques bien identifiables de fluides viscoélastiques. Dans ces expériences de déplacement immiscible, une huile de viscosité inférieure sera déplacée par un fluide newtonien de référence et par des fluides viscoélastiques que nous allons choisir, formuler et caractériser. Les expériences de déplacement dans une cellule Hele-Shaw mettent en évidence que le caractère élastique des formulations modifie les conditions de déplacement, surtout à vitesses élevées. De même nous pouvons observer une série d'expériences où la tension interfaciale du système fluide – huile a été diminuée pour monter que l'effet de l'élasticité apparaît sous ces conditions. Nous pouvons aussi observer comme les tendances se maintiennent à niveau microscopique, où la pénétration des fluides viscoélastiques dans des pores modèle est plus prononcée par rapport a un fluide newtonien. Finalement nous proposons un modèle simple qui prend en compte les propriétés élastiques des fluides en la déformation de l'interface fluide / huile que donne comme résultat une différence dans le déplacement immiscible quand on compare par rapport aux fluides newtoniens / Conditions of oil displacement in simple geometries are studied according to clearly identifiable characteristics of viscoelastic fluids. In these immiscible displacement experiments, a lower viscosity oil will be displaced using a reference Newtonian fluid and viscoelastic fluids that we will select, develop and characterize. The displacement experiments in a Hele-Shaw cell show that the elastic nature of formulations alters displacement conditions, especially at high velocities. Similarly we can observe a series of experiments in which the interfacial tension of the system fluid-oil was decreased to show that the effect of the elasticity appears under these conditions. We can also observe how the trends remain at the microscopic level, where the penetration of viscoelastic fluids in a model pore is more pronounced compared to a Newtonian fluid. Finally we propose a simple model which takes into account the elastic properties of fluids in deformation of the fluid-oil interface that results in a difference for immiscible displacement when compared to Newtonian fluids

La perturbation d’un système peut donner lieu à de la propagation d’onde. Une façon classique d’appréhender ce phénomène est de rechercher les modes propres de vibration du milieu. Mathématiquement, trouver ces modes consiste à rechercher les valeurs et fonctions propres de l’opérateur de propagation. Cependant, d’un point de vue numérique, l’opération peut s’avérer coûteuse car les matrices peuvent avoir de très grandes tailles. En outre, dans la plupart des applications, des incertitudes sont inévitablement associées à notre modèle. La question se pose alors de savoir s’il faut attribuer d’importantes ressources de calcul pour une simulation dont la précision du résultat n’est pas assurée. Nous proposons dans cette thèse une démarche qui permet à la fois de mieux comprendre l’influence des incertitudes sur la propagation et de réduire considérablement les coûts de calcul pour la propagation des infrasons dans l’atmosphère. L’idée principale est que tous les modes n’ont pas la même importance et souvent, seule une poignée d’entre eux suffit à décrire le phénomène sans perte notable de précision. Ces modes s’avèrent être ceux qui sont les plus sensibles aux perturbations atmosphériques. Plus précisément, l’analyse de sensibilité permet d’identifier les structures de l’atmosphère les plus influentes, les groupes de modes qui leur sont associés et les parties du signal infrasonore qui leur correspondent. Ces groupes de modes peuvent être spécifiquement ciblés dans un calcul de spectre au moyen de techniques de projection sur des sous-espace de Krylov, ce qui implique un gain important en coût de calcul. Cette méthode de réduction de modèle peut être appliquée dans un cadre statistique et l’estimation de l’espérance et de la variance du résultat s’effectue là aussi sans perte notable de précision et avec un coût réduit. / The perturbation of a system can give rise to wave propagation. A classical approach to understand this phenomenon is to look for natural modes of vibration of the medium. Mathematically, finding these modes requires to seek the eigenvalues and eigenfunctions of the propagation operator. However, from a numerical point of view, the operation can be costly because the matrices can be of very large size. Furthermore, in most applications, uncertainties are inevitably associated with our model. The question then arises as to whether we should allocate significant computational resources for simulation while the accuracy of the result is not guaranteed. We propose in this thesis an approach that allows both a better understanding of the influence of uncertainties on the propagation and a significant decrease of computational costs for infrasound propagation in the atmosphere. The main idea is that all modes do not have the same importance and only a few of them is often sufficient to account for the phenomenon without a significant loss of accuracy. These modes appear to be those which are most sensitive to atmospheric disturbances. Specifically, a sensitivity analysis is used to identify the most influential structures of the atmosphere, the associated groups of modes and their associated parts of the infrasound signal. These groups of modes can be specifically targeted in a spectrum calculation with the projection of the operator onto Krylov subspaces, that allows a significant decrease of the computational cost. This method of model reduction can be applied in a statistical framework as well and estimations of the expectation and the variance of the results are carried out without a significant loss of accuracy and still with a low cost.

A principal motivação desse estudo é a análise da quantidade de sangue recebido em transfusão (padronizada pelo peso) por crianças com problemas hepáticos. Essa quantidade apresenta distribuição assimétrica, além de valores iguais a zero para as crianças que não receberam transfusão. Os modelos lineares generalizados, usuais para variáveis positivas, não permitem a inclusão de zeros. Para os dados positivos, foram ajustados tais modelos com distribuição gama e normal inversa. Também foi considerado o modelo log-normal. A análise de resíduos padronizados indicou heterocedasticidade, e portanto a variabilidade extra foi modelada utilizando a classe de modelos GAMLSS. A terceira abordagem consiste em modelos baseados na mistura de zeros e distribuições para valores positivos, incluídos recentemente na família dos modelos GAMLSS. Estes aliam a distribuição assimétrica para os dados positivos e a probabilidade da ocorrência de zeros. Na análise dos dados de transfusão, observa-se que a distribuição normal inversa apresentou melhor ajuste por acomodar dados com forte assimetria em relação às demais distribuições consideradas. Foram significativos os efeitos das variáveis explicativas Kasai (ocorrência de operação prévia) e PELD (nível de uma medida da gravidade do paciente com 4 níveis) assim como os efeitos de interação sobre a média e variabilidade da quantidade de sangue recebida. A possibilidade de acrescentar efeitos de variáveis explicativas para modelar o parâmetro de dispersão, permite que a variabilidade extra, além de sua dependência da média, seja melhor explicada e melhore o ajuste do modelo. A probabilidade de não receber transfusão depende de modo significativo somente de PELD. A proposta de um só modelo que alia a presença de zeros e diversas distribuições assimétricas facilita o ajuste dos dados e a análise de resíduos. Seus resultados são equivalentes à abordagem em que a ocorrência ou não de transfusão é analisada por meio de modelo logístico independente da modelagem dos dados positivos com distribuições assimétricas. / The main motivation of this study is to analyze the amount of blood transfusions received (by weight) of children with liver problems. This amount shows asymmetric distribution as well as present zero values for children who did not receive transfusions. The usual generalized linear models for positive variables do not allow the inclusion of zeros. For positive data, such models with gamma and inverse normal distributions were fitted in this study. Log-normal distribution was also considered. Analysis of the standardized residuals indicated heterocedasticity and therefore the extra variability was modelled using GAMLSS. The third approach consists of models based on a mixture of zeros and distributions for positive values, also recently included in the family of GAMLSS models. These models combine the asymmetric distribution of positive data and the probability of occurrence of zeros. In the data analysis of transfusion, the inverse normal distribution showed better goodness of fit to allow adjustment of data with greater asymmetry than the other distributions considered. The effects of the explanatory variables Kasai (occurrence of previous operation) and PELD level (a measure of the severity of the patient with 4 levels) and interaction effects on the mean and variability of the amount of blood received were signicant. The inclusion of explanatory variables to model the dispersion parameter, allows to model the extra variability, beyond its dependence on the average, and improves fitness of the model. The probability of not receiving transfusion depends signicantly only PELD. The proposal of a unified model that combines the presence of zeros and several asymmetric distributions greatly facilitates the fitness of the model and the evaluation of fitness. An advantage is the equivalence between this model and a separate logistic model to for the probability of the occurrence of transfusion and a model for the positive skewed data.

Buracos negros têm as suas oscilações próprias, que são chamadas modos quase-normais. As oscilações próprias de buracos negros astrofísicos podem ser observadas no futuro mais próximo com a ajuda de detectores de ondas gravitacionais. Os modos quase-normais são também muito importantes no contexto de teste da estabilidade de objetos negros, da correspondência anti-deSitter/ Teoria Campos Conformes (AdS/CFT) e nas teorias em dimensões mais altas, como os cenários de mundo-brana e teoria das cordas. Esta tese revê um numero de trabalhos, que fornecem um estudo completo do espectro quase normal de grande classe de buracos negros em quatro e mais altas dimensões para campos de vários spins e perturbações gravitacionais. Foi estudada numericamente a dependência dos modos quase-normais sobre um numero de fatores, como a presença da constante cosmológica, o parâmetro de Gauss-Bonnet ou o a éter no espaco-tempo, a dependência do espectro sobre os parâmetros do buraco negro e os campos em consideração. Pela analise do espectro quase-normal, foi estudada a estabilidade de buracos negros Reissner-Nordstrom-de Sitter em dimensões mais altas, buracos negros de Kaluza-Klein com horizontes esmagados, buracos negros de Gauss-Bonnet e cordas negras. Uma atenção especial foi prestada à evolução de campos massivos no contexto de vários buracos negros. Foram considerados os seus toques quase-normais e as caudas de tempo tardio. Alem disso, foram apresentadas duas novas técnicas numéricas: uma generalização da melhora de Nollert para do método de Frobenius para problemas em dimensões mais altas e um método qualitativamente novo, que permite calcular freqüências quase-normais de buracos negros, cujas métricas não são conhecidas analiticamente. Também foi considerada uma possibilidade da construção do análogo acústico do buraco negro de Schwarzschild. / Black holes have their proper oscillations, which are called the quasi-normal modes. The proper oscillations of astrophysical black holes can be observed in the nearest future with the help of gravitational wave detectors. Quasi-normal modes are also very important in the context of testing of the stability of black objects, the anti-de Sitter/ Conformal Field Theory (AdS/CFT) correspondence and in higher dimensional theories, such as the brane-world scenarios and string theory. This dissertation reviews a number of works, which provide a thorough study of the quasi-normal spectrum of a wide class of black holes in four and higher dimensions for fields of various spin and gravitational perturbations. We have studied numerically the dependance of the quasi-normal modes on a number of factors, such as the presence of the cosmological constant, the Gauss-Bonnet parameter or the aether in the space-time, the dependance of the spectrum on parameters of the black hole and fields under consideration. By the analysis of the quasi-normal spectrum, we have studied the stability of higher dimensional Reissner-Nordstr¨om-de Sitter black holes, Kaluza-Klein black holes with squashed horizons, Gauss-Bonnet black holes and black strings. Special attention is paid to the evolution of massive fields in the background of various black holes. We have considered their quasi-normal ringing and the late-time tails. In addition, we present two new numerical techniques: a generalisation of the Nollert improvement of the Frobenius method for higher dimensional problems and a qualitatively new method, which allows to calculate quasi-normal frequencies for black holes, which metrics are not known analytically. Also we considered a possibility of construction of the acoustic analogue of the Schwarzschild black hole.

Estudamos a evolução temporal de perturbações escalares na vizinhança de uma estrela com densidade uniforme que colapsa em um buraco negro. O trabalho começa com um estudo básico de gravitação e modos quasi-normais. O objetivo principal é resolver a equação de Klein-Gordon sem massa para a perturbação escalar, cuja solução depende de métodos numéricos. Com este objetivo, tratamos os aspectos teóricos de buracos negros e estrelas a partir da solução prevista pela Relatividade Geral para um buraco negro, estrelas com densidade uniforme e estrelas em colapso. Estudamos também uma maneira de reduzirmos a Equação de Klein-Gordon para uma forma conveniente de ser integrada, assim como os métodos numéricos necessários para resolver essa equação. Encontramos soluções para os modos variando a massa M, o raio inicial R e o rótulo do momento angular l. Essas soluções são irregulares em muitas situações, mas em geral elas são crescentes, de acordo com o comportamente observado de explosões de Supernovas. / This work is a study on the time evolution of scalar perturbations around a star collapsing to a black hole. It starts with a basic study of gravitation and quasi-normal modes. The aim is to derive the solution of the massless Klein-Gordon equation, that depends on numerical methods. Aiming at this goal, we studied theoretical aspects of stars, black holes and gravitational collapse. The methods include coordinate substitutions to modify the Klein-Gordon equation to a simple form. We also studied numerical methods for partial differential equations. Solutions of the quasi-normal modes were found with different values of M, R and l. The solutions are irregular in several situations, but some of them display increasing modes, that could be explained by the explosive behavior of Supernovas.

Introdução: o modelo predominante de assistência ao parto no Brasil caracteriza-se pelo uso abusivo ou inadequado de intervenções e cerceamento dos direitos da parturiente (restrição à presença de acompanhante de escolha da mulher, realização de amniotomia de rotina durante o trabalho de parto, posição litotômica de rotina, infusão intravenosa de ocitocina de rotina, puxo dirigido e pressão no fundo uterino da parturiente durante a expulsão fetal) em todos os períodos clínicos do parto. Sabe-se que esse modelo pode ser modificado com a adoção das boas práticas de assistência ao parto normal preconizadas pela Organização Mundial da Saúde. Embora as melhores práticas no parto e nascimento estejam fundamentadas em evidências científicas, faltam pesquisas sobre sua implementação na prática clínica. Objetivo geral: avaliar o impacto da implementação das práticas baseadas em evidências na assistência ao parto normal. Método: estudo de intervenção quase experimental, tipo antes e depois, baseado na metodologia de implementação de evidências científicas na prática clínica do Instituto Joanna Briggs. Foi conduzido no Hospital da Mulher Mãe Luzia, maternidade pública de referência para a assistência obstétrica em Macapá, Amapá. Foram entrevistados 42 profissionais (enfermeiros e médicos obstetras e residentes das duas categorias) e 280 mulheres atendidas no trabalho de parto e parto. Também foram analisados dados de 555 prontuários de puérperas. A pesquisa foi desenvolvida em três fases: auditoria de base (fase 1), intervenção educativa (fase 2) e auditoria pós-intervenção (fase 3). A intervenção educativa consistiu em um seminário denominado Seminário de práticas baseadas em evidências científicas na assistência ao parto normal, oferecido para os profissionais. A coleta de dados ocorreu entre julho de 2015 e março de 2016. Os achados foram analisados comparando-se os dados das fases 1 e 3, adotando-se o nível de significância de 5%. Este estudo foi aprovado pelo Comitê de Ética em Pesquisa da Escola de Enfermagem da Universidade de São Paulo. Resultados: após a intervenção educativa, houve incremento de 8,3 p.p. na taxa de parto normal. Na entrevista com as mulheres, constatou-se aumento de 10,0 p.p. (p=0,002) da presença do acompanhante durante o trabalho de parto e de 31,4 p.p. (p<0,001) no uso da posição vertical ou cócoras. A realização de amniotomia foi reduzida em 16,8 p.p. (p=0,005), o uso de posição litotômica em 24,3 p.p. (p<0,001), a utilização de ocitocina em 17,1 p.p. (p=0,004), os puxos dirigidos em 29,3 p.p. (p<0,001) e a manobra de Kristeller em 10,7 p.p. (p=0,013). Na perspectiva dos profissionais, houve redução da prescrição ou administração de ocitocina de 29,6 p.p. (p=0,005). Na análise dos dados dos prontuários, observou-se redução significativa da taxa de amniotomia em 29,5 p.p. (p<0,001) e de posição litotômica em 1,5 p.p. (p=0,013), enquanto a taxa de posição vertical ou cócoras apresentou incremento de 2,2 p.p. (p=0,013). Conclusões: a intervenção educativa revelou impacto positivo na melhora da assistência à mulher durante o trabalho de parto e parto, com aumento da taxa de parto normal e, também, na visão das mulheres, que alegaram ter mais acompanhantes de sua escolha, poder adotar mais posições verticalizadas no período expulsivo, utilizar menos ocitocina, puxos dirigidos e manobra de Kristeller. Esses resultados conferem em parte com o dos profissionais, que citaram realizar menos orientação de puxos dirigidos e prescreverem menos ocitocina. Também coincidem parcialmente com as anotações dos prontuários, que incluem aumento das posições verticais e redução da posição litotômica e da prática de amniotomia. No entanto, verificou-se que os profissionais continuam empregando práticas como posição litotômica de rotina, puxos dirigidos e manobra de Kristeller, no período expulsivo. Conclui-se que houve um impacto positivo na proposta conduzida, mas mostra que o processo de implementação de evidências científicas na assistência ao parto normal adotado não foi capaz de obter sucesso completo na mudança das práticas obstétricas dos profissionais participantes. / Background: the predominant model of childbirth care in Brazil is characterized by abusive or inappropriate use of interventions and parturient\'s rights disrespect (such as restriction of presence of the chosen companion of the woman, routine amniotomy, routine lithotomy position, routine oxytocin intravenous infusion, directed pushing, and fundal pressure during second stage of labour) in all clinical periods of the childbirth. This model of care could be modified adopting good practices on maternal health recommended by World Health Organization. Despite the evidence-based best practices in childbirth, there is a lack of research on its implementation into clinical practice. Aim: to evaluate the impact of the implementation of evidence-based practices on normal birth. Method: before and after quasi-experimental study based on Joanna Briggs Institute Evidence Implementation method. It was conducted at Mãe Luzia Women\'s Hospital, a reference maternity hospital for maternity care in Macapá, Amapá, Brazil. Interview of 42 professionals (nurses, obstetricians and residents of both categories) and 280 women who were attended during labour and birth. Data from 555 puerperium records were also analysed. The research was developed in three phases: baseline audit (phase 1), educational intervention (phase 2) and post-intervention audit (phase 3).The educational intervention was a seminar named \"Scientific evidence-based practices on normal childbirth seminar\", attended by the professionals. Data were collected from July 2015 to March 2016. The findings were analysed comparing the data from phases 1 and 3, adopting a level of significance of 5%. There search was approved by the Research Ethics Committee from School of Nursing of University of Sao Paulo. Results: after the educational intervention, there was an increase of 8.3 p.p. in normal birth rate. According to the interviewed women, there was an increase of 10.0 p.p. (p = 0.002) in the presence of companion during labour and of 31.4 p.p. (p <0.001) in the adoption of vertical or squatting position to give birth. The amniotomy was reduced by 16.8 p.p. (p = 0.005), lithotomy position by 24.3 p.p. (p<0.001), oxytocin infusion by 17.1 p.p. (p = 0.004), directed pushing by 29.3 p.p. (p <0.001) and Kristeller maneuver by 10.7 p.p. (p = 0.013). In the professionals\' perspective, it was found a reduction in oxytocin prescription (29.6 p.p.; p = 0.005). In medical records data analysis there was a reduction on amniotomy rate (29.5 p.p.; p<0.001) and lithotomy position (1.5 p.p.; p = 0.013), while vertical or squatting position had increased in 2.2 p.p. (p = 0.013). Conclusions: the educational intervention showed a positive impact improving women´s care during labour and birth, increasing normal birth rate. Also in the women´s view, having more companions of their choice, they were able to adopt vertical positions in the second stage of labour and had less oxytocin infusion, directed pushing and Kristeller maneuver. These results confer in part with these of the interviews with professionals, who have cited performing less direct pushing and prescribed less oxytocin infusion. These results are also similar with the medical records, which include increase in the adoption of vertical positions and the reduction of lithotomic position and amniotomy. However, it was verified that professionals still practice lithotomic position, directed pushing and Kristeller maneuver in the second stage of labour. The educational intervention had a positive impact, but did not have complete success in changing professional practices.

Thesis advisor: Donald Fishman / This paper will study three particular accidents in the nuclear industry: Three Mile Island, Chernobyl, and the Fukushima Daiichi plant. These crises will be evaluated through a crisis management framework, using two main accident theories: Normal Accident Theory, and High Reliability Theory. The examination of the crises and the organizations involved will show that no matter how reliable the complex systems are, accidents are inevitable in the nuclear industry. High reliability theory expresses an ideal for complex organizations. While following the theory’s suggestions can limit some problems from occurring, acting as a mindful and reliable organization cannot prevent all disasters. The three cases presented in this paper will show that Normal Accident Theory must be accepted by the nuclear industry. Thus, governments and nuclear power plant operators must be prepared with crisis management plans in order to successfully handle emergency situations and limit damages. The first part of this paper will introduce Normal Accident Theory and High Reliability Theory. Then, after a brief overview of the basics of nuclear power, Three Mile Island, Chernobyl, and Fukushima Daiichi will be examined in the theoretical framework, including a discussion of each event’s crisis management techniques. / Thesis (BA) — Boston College, 2012. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: College Honors Program. / Discipline: Communication.

Thesis advisor: George R. Meyerhoff / Recent advances in normal surface algorithms enable the determination by computer of the hyperbolicity of compact orientable 3-manifolds with zero Euler characteristic and nonempty boundary. Recent advances in hyperbolic geometry enable the determination by computer of the Dehn paternity relation between two orientable compact hyperbolic 3-manifolds. Presented here is an exposition of these developments, along with prototype implementations of one of these determinations in software. These have applications to two questions about Mom technology. / Thesis (PhD) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Mathematics.