Esta pesquisa trata das experiências anômalas relatadas ou observadas durante o período da infância e adolescência. Experiências anômalas são todas aquelas que fogem do consenso de normalidade, ou que não são explicadas pela psicologia tradicional e o mainstream científico. O texto apresenta as principais experiências anômalas infantis, com especial enfoque para as experiências de percepção extrassensorial (ESP). Três periódicos específicos da área foram selecionados e as publicações relacionadas ao tema são apresentadas e discutidas. Um teste experimental computadorizado foi desenvolvido especificamente para esta pesquisa com o objetivo de modernizar e replicar um experimento realizado em escolas holandesas na década de 1950. Com a aplicação do teste avaliou-se a ocorrência de percepção extrassensorial entre um grupo de professores e alunos das séries iniciais do ensino fundamental. O teste foi aplicado em uma escola particular da cidade de São Paulo. Os resultados gerais foram positivos, sem atingir, contudo, significância estatística. Avaliou-se também a correlação entre os resultados obtidos e algumas variáveis psicológicas. As variáveis escolhidas foram o vínculo afetivo estabelecido na relação professor/aluno e o efeito da expectativa. As correlações para ambas as variáveis foram positivas e estatisticamente significantes. Os resultados são discutidos e comparados àqueles encontrados na literatura específica / This research addresses the anomalous experiences reported or spontaneously observed in childhood and adolescence. An anomalous experience is every one that deviates from our sense of normality, or that cannot be explained by traditional psychology or the scientific mainstream. The main anomalous experiences in childhood are presented and discussed, with special attention dedicated to the experiences of the extra-sensory perception (ESP) type. Three journals of the field were chosen and carefully examed in search for articles addressing the subject. These articles are also presented and discussed. An experimental computerized test was specifically developed with the purpose of updating and replicating a study conducted in Dutch schools in the 1950s. The experiment evaluated the ocurrence of extra-sensory perception among teachers and pupils of first and second grade groups. The study was conducted at a private school in São Paulo. Overall results were positive, but not significant. The scores were correlated to two psychological variables: teacher/pupil bond and expectation. Both variables correlated positively and significantly with the scores. The results are discussed and compared to those available in the literature

Depuis les premières structures de protéines déterminées dans les années 1950, la cristallographie aux rayons X s’est imposée comme une méthode de choix pour l’obtention de données structurales à l’échelle atomique. Malgré les progrès technologiques qui ont révolutionné cette méthode (sources synchrotron, détecteurs pixel, programmes informatiques performants), l’obtention d’une carte de densité électronique permettant de modéliser la structure d’une macromolécule demeure toujours limitée par deux goulots d’étranglement qui sont, l’obtention de cristaux de la macromolécule d’intérêt et la résolution du problème des phases inhérent à l’enregistrement des données de diffraction.Cette thèse présente un nouveau complexe de lanthanide appelé « crystallophore » (Tb-Xo4). Cette molécule a été développé en collaboration avec Olivier Maury et François Riobé du laboratoire de chimie Matériaux Fonctionnels et Photonique (ENS –Lyon). La conception de ce nouveau complexe est basée sur quinze années de développement dans le domaine de la biologie structurale. Cette thèse présente les effets uniques induits par de Tb-Xo4 sur la cristallisation et sur la détermination des structures de macromolécules biologiques. L’ajout de Tb-Xo4 au cours de la cristallisation permet d’induire un nombre important de conditions de cristallisation exploitables dont certaines sont propres à la présence du crystallophore. L’analyse des structures atomiques de différentes protéines co-cristallisées en présence de Tb-Xo4 a permis à la fois de mettre en avant le pouvoir phasant élevé de Tb-Xo4 mais également de décrire finement l’interaction supramoléculaire du complexe avec la surface des macromolécules. Ce travail a conduit à la mise en place de protocoles de cristallisation et de phasage des macromolécules biologique assistés par Tb-Xo4. Sur la base de la compréhension du mode d’interaction de ce nouveau composé, cette thèse aboutit à la proposition d’un modèle expliquant les propriétés uniques de ce nouveau complexe de lanthanide. / Since the first protein structure determined in the 1950s, X-ray crystallography emerged as a method of choice to obtain structural data at atomic resolution. Despite technological advances such as new synchrotron sources, hybrid pixel detectors, and high-performance softwares, obtaining an electron density map of a biological macromolecule is always limited by two major bottlenecks namely, producing high quality single crystals and solving the phase problem.This thesis presents a new lanthanide complex called “Crystallophore” (Tb-Xo4). This compound has been developed in collaboration with Olivier Maury and François Riobé of the Laboratoire de chimie Matériaux Fonctionnels et Photonique (ENS –Lyon). The design of this new complex is based on fifteen years of development in the field of structural biology. This thesis highlights the effects of Tb-Xo4 on the crystallisation and the structure determination of biological macromolecules. Indeed, the addition of Tb-Xo4 to a protein solution induces a large number of new and unique crystallization conditions. The analysis of the structures of several proteins co-crystallized with Tb-Xo4 allowed both, to highlight the high phasing power of Tb-Xo4 but also to describe finely the supramolecular interaction of the complex with the macromolecules. This work led to protocols dedicated to crystallization and phasing assisted with Tb-Xo4. Finally, this thesis leads to a model explaining the unique properties of this new lanthanide complex.

A presente pesquisa pretendeu investigar variáveis e processos psicológicos, com ênfase naqueles de interesse imediato da psicologia social, que alicerçam crenças e experiências subjetivas relacionadas a alienígenas, óvnis e paranormalidade. A principal perspectiva para o enfrentamento da questão foi a etnografia, por ela permitir o estudo próximo de realidades pessoal e culturalmente significativas ao redor do tema. As incursões etnográficas se deram em contextos brasileiros urbanos e rurais radicalmente marcados por tais experiências e sistemas de crença-significado. Foram eles a Serra do Cipó e um grupo de contatados em Minas Gerais, um grupo de contatados no Mato Grosso do Sul, a Serra do Roncador, no Mato Grosso, e a comunidade ufológica brasileira, caracterizando uma etnografia multissituada. O tema foi escolhido devido à constatação prévia de que contatos com alienígenas compõem uma das categorias menos investigadas de experiências anômalas, especialmente no Brasil, mas cujas elevada prevalência e conotações psicológicas possuem dimensões superlativas na contemporaneidade, além de constituírem oportunidade privilegiada para compreensão da última. Assim, comparei os diferentes contextos e discuti dimensões intra e intersubjetivas tanto locais quanto transculturais relativas a crenças e experiências anômalas que incluem alienígenas. Complementarmente, discuti qualitativamente dimensões psicológicas das experiências de forma atenta a nuances tanto particulares quanto possivelmente transculturais das mesmas, propondo uma síntese teórica ao final que complementa a pesquisa quantitativa de mestrado que previamente conduzi sobre características de personalidade e de saúde mental de protagonistas de episódios do gênero. A pesquisa atingiu conclusões que perpassam temas diversos como o caráter primário da experiência direta, esquemas cognitivos, dimensões religiosas e espirituais, diferentes formas de racionalidade, a crise de sentido da pós-modernidade, sugestionabilidade, contraintuição, identidade, dissonância cognitiva, entre outros a montar um panorama dinâmico das experiências e crenças relativas a alienígenas / This research intended to investigate psychological variables and processes underpinning beliefs and subjective experiences related to \"aliens\", \"UFOs\" and the \"paranormal\", with emphasis on those of immediate interest to social psychology. The main perspective to address the issue was ethnography, for it allows the close study of personally and culturally significant realities around the theme. The ethnographic incursions took place in urban and rural Brazilian contexts radically marked by such experiences and belief-meaning systems. They were Serra do Cipó and a group of \"contactees\" in Minas Gerais, a group of \"contactees\" in Mato Grosso do Sul, Serra do Roncador, in Mato Grosso, and the \"Brazilian UFO community\", featuring a multi-situated ethnography. The theme was chosen because of the previous finding that \"alien contacts\" compose one of the fewer investigated categories of anomalous experiences, especially in Brazil, but whose high prevalence and psychological connotations have superlative dimensions in contemporaneity, in addition to being a prime opportunity for understanding the last one. So, I compared the different contexts and discussed local and cross-cultural subjective dimensions related to anomalous beliefs and experiences that include \"aliens\". In addition, I discussed qualitatively some psychological dimensions of experiences attentively to particular and possibly cross-cultural aspects of them, proposing a theoretical synthesis at the end that complements my previous quantitative masters research on personality traits and mental health of protagonists of such episodes. The present research reached conclusions that underlie diverse subjects such as the primary feature of the direct experience, cognitive schemas, religious and spiritual dimensions, different forms of rationality, the crisis of meaning in the postmodernity, suggestibility, counter-intuition, identity, cognitive dissonance, among others that form a dynamic panorama of experiences and beliefs regarding \"aliens\"

Molibdatos têm atraído grande atenção devido à existência de compostos com caráter elétrico unidimensional como conseqüência da presença de cadeias contendo ligações de Mo-O ou Mo-Mo em suas estruturas cristalinas. Com o objetivo de estudar molibdatos com esta característica, amostras policristalinas do sistema K-Mo-O foram preparadas pelo método de reação de difusão no estado sólido e caracterizadas por difratometria de raios x, propriedades elétricas e magnéticas. Estes resultados demonstram a existência de uma nova fase neste sistema com estequiometria KxMoO2-&#948;. Medidas da resistência elétrica em função da temperatura deste material mostram comportamento metálico anômalo que está relacionado a um ordenamento antiferromagnético. Foi observado ainda que a anomalia na resistência elétrica em baixas temperaturas (T < TM) comporta-se segundo uma lei de potência com expoente próximo de 0,5, o que sugere que o comportamento elétrico do KxMoO2-&#948; pode ser descrito por um mecanismo de condutividade unidimensional. / Molybdates have attracted great attention due to the existence of compounds which show one-dimensional electrical behavior as consequence of the channel containing Mo-O or Mo-Mo bonds in their crystalline structure. In order to study molybdates exhibiting onedimensional conductivity, polycrystalline samples of the K-Mo-O system were prepared using the solid state diffusion reaction method and characterized by X-ray powder diffractometry, electrical and magnetic properties. These results demonstrate the existence of a new phase in this system with KxMoO2-&#948; stoichiometry. Electrical resistance as a function of temperature measurements for this compound have shown anomalous metallic behavior which is related to an antiferromagnetic ordering. It has been also observed that the anomaly in the electrical resistance at low temperatures (T < TM) is fitted by power law temperature dependence with an exponent near 0.5 which suggests that the electrical behavior of the KxMoO2-&#948; can be well described by the one-dimensional conducting mechanism.

Este trabalho apresenta o estudo das propriedades físicas de amostras de KxMoO2-? e MoOy. São reportados resultados de difratometria de raios X e de nêutrons, cálculo de densidade de estados pela teoria do funcional da densidade, medidas de espectroscopia de fotoemissão, resistividade elétrica, magnetização, calor específico e expansão térmica. Resultados de difratometria de raios X e de nêutrons, com ajustes baseados em simulações realizadas com o programa GSAS, permitiram selecionar as amostras monofásicas e de boa qualidade. As medidas de espectroscopia de fotoemissão mostram que a existência de alta fração Mo3+/Mo4+ em diversas amostras de KxMoO2-? e MoOy é a responsável pela anomalia da resistividade elétrica descrita pela lei de potência prevista no modelo do líquido de Luttinger (LL). A observação da anomalia nas curvas de resistividade elétrica em amostras de MoO2 deficientes em oxigênio suporta que tal comportamento está relacionado à presença de íons Mo3+ e não com a presença de K. Resultados de magnetização e resistividade elétrica confirmaram a existência de supercondutividade no sistema K-Mo-O. Foi observada que a temperatura crítica (TC) é função da composição inicial de K, sendo que foi encontrada a mais alta TC reportada para este sistema (TC ~9,5 K). Medidas de magnetização mostraram ainda a coexistência de supercondutividade e magnetismo no composto KxMoO2-?. Foi ainda observada uma transição do tipo metal de Bose para isolante em uma amostra de KxMoO2-? que reforça a evidência da formação de pares de Cooper nesse sistema. Por fim, medidas de calor específico, expansão térmica e resistividade elétrica evidenciaram a existência de uma transição de fase de primeira ordem em altas temperaturas (entre 250 e 270 K) tanto em amostras policristalinas de KxMoO2-? e MoOy quanto em monocristais de MoO2. A transição observada no MoO2 nunca foi reportada para este material. Esta transição é discutida com base na movimentação dos átomos de Mo existentes nas ligações unidimensionais de Mo-Mo e nas distorções dos octaedros de MoO6 presentes na sua estrutura cristalina. / This work presents the study of physical properties in polycrystalline samples of KxMoO2-?, and MoOy. We present results of X-ray and Neutrons diffraction patterns, density of states calculations by density functional theory, photoemission spectroscopy, electrical resistivity, magnetization, specific heat, and thermal expansion measurements. X-ray and neutrons diffraction results as well as calculations of the structure and diffractograms carried out by simulations using GSAS shown which the samples are high quality. Photoemission spectroscopy measurements shown the existence of Mo3+/Mo4+ in high fraction for KxMoO2-? and MoOy which are responsible to electrical anomalous behavior described by powder law predicted in the Luttinger Liquid theory. The observation of anomalous is related to Mo3+ ions in the samples. Magnetization and electrical resistivity confirm the existence of superconductivity in K-Mo-O system. It was observed that the critical temperature (TC) is a function of the starting composition of K and the higher TC found out and reported for this system (TC ~9.5 K). Magnetization measurements also have shown the coexistence of superconductivity and magnetism in KxMoO2-?. It was observed a Bose metal-insulator transition in K0.05MoO2-? which further evidence of the formation of Cooper pairs in the system. Finally, specific heat measurements, thermal expansion and electrical resistivity evidenced the existence of first order phase transition in high temperatures (between 250 and 270 K) in KxMoO2-? and MoOy polycrystalline as well as MoO2 single crystal. This transition is discussed looking for Mo atoms moving in the one-dimensional links Mo-Mo and of the distortions of MoO6 octahedra in the crystalline structure.

A presente pesquisa pretendeu investigar variáveis e processos psicológicos, com ênfase naqueles de interesse imediato da psicologia social, que alicerçam crenças e experiências subjetivas relacionadas a alienígenas, óvnis e paranormalidade. A principal perspectiva para o enfrentamento da questão foi a etnografia, por ela permitir o estudo próximo de realidades pessoal e culturalmente significativas ao redor do tema. As incursões etnográficas se deram em contextos brasileiros urbanos e rurais radicalmente marcados por tais experiências e sistemas de crença-significado. Foram eles a Serra do Cipó e um grupo de contatados em Minas Gerais, um grupo de contatados no Mato Grosso do Sul, a Serra do Roncador, no Mato Grosso, e a comunidade ufológica brasileira, caracterizando uma etnografia multissituada. O tema foi escolhido devido à constatação prévia de que contatos com alienígenas compõem uma das categorias menos investigadas de experiências anômalas, especialmente no Brasil, mas cujas elevada prevalência e conotações psicológicas possuem dimensões superlativas na contemporaneidade, além de constituírem oportunidade privilegiada para compreensão da última. Assim, comparei os diferentes contextos e discuti dimensões intra e intersubjetivas tanto locais quanto transculturais relativas a crenças e experiências anômalas que incluem alienígenas. Complementarmente, discuti qualitativamente dimensões psicológicas das experiências de forma atenta a nuances tanto particulares quanto possivelmente transculturais das mesmas, propondo uma síntese teórica ao final que complementa a pesquisa quantitativa de mestrado que previamente conduzi sobre características de personalidade e de saúde mental de protagonistas de episódios do gênero. A pesquisa atingiu conclusões que perpassam temas diversos como o caráter primário da experiência direta, esquemas cognitivos, dimensões religiosas e espirituais, diferentes formas de racionalidade, a crise de sentido da pós-modernidade, sugestionabilidade, contraintuição, identidade, dissonância cognitiva, entre outros a montar um panorama dinâmico das experiências e crenças relativas a alienígenas / This research intended to investigate psychological variables and processes underpinning beliefs and subjective experiences related to \"aliens\", \"UFOs\" and the \"paranormal\", with emphasis on those of immediate interest to social psychology. The main perspective to address the issue was ethnography, for it allows the close study of personally and culturally significant realities around the theme. The ethnographic incursions took place in urban and rural Brazilian contexts radically marked by such experiences and belief-meaning systems. They were Serra do Cipó and a group of \"contactees\" in Minas Gerais, a group of \"contactees\" in Mato Grosso do Sul, Serra do Roncador, in Mato Grosso, and the \"Brazilian UFO community\", featuring a multi-situated ethnography. The theme was chosen because of the previous finding that \"alien contacts\" compose one of the fewer investigated categories of anomalous experiences, especially in Brazil, but whose high prevalence and psychological connotations have superlative dimensions in contemporaneity, in addition to being a prime opportunity for understanding the last one. So, I compared the different contexts and discussed local and cross-cultural subjective dimensions related to anomalous beliefs and experiences that include \"aliens\". In addition, I discussed qualitatively some psychological dimensions of experiences attentively to particular and possibly cross-cultural aspects of them, proposing a theoretical synthesis at the end that complements my previous quantitative masters research on personality traits and mental health of protagonists of such episodes. The present research reached conclusions that underlie diverse subjects such as the primary feature of the direct experience, cognitive schemas, religious and spiritual dimensions, different forms of rationality, the crisis of meaning in the postmodernity, suggestibility, counter-intuition, identity, cognitive dissonance, among others that form a dynamic panorama of experiences and beliefs regarding \"aliens\"

Doctor of Philosophy / Department of Chemistry / Daniel A. Higgins / This dissertation describes single-molecule tracking (SMT) studies for the quantitative characterization of one-dimensional (1D) solvent-filled surfactant-templated mesoporous silica (STMS) materials and other nanostructured materials, such as double-stranded DNA. SMT permits the simultaneous and quantitative assessment of the nanoscale and microscale morphologies and mass-transport properties of the materials with nanometer-scale spatial resolution. The efficiency and selectivity of catalytic reactions and chemical separations occurring in liquid-filled mesoporous materials are governed by the translational and orientational mobilities and surface interactions of the incorporated reagents and analytes. Polarization dependent SMT results demonstrate that the dye molecules used as probes of materials nanostructure are tightly confined within the one-dimensional (1D) pores of surfactant-templated mesoporous silica films. Spectroscopic single molecule tracking (sSMT) data reveal that the hydrophobic probe dyes are confined within nonpolar regions of the nanomaterials For this dissertation, surfactant templated mesoporous silica films were prepared by the spin coating of acid catalyzed tetramethoxysilane (TMOS)-based silica sols on glass substrates in the presence of Cetyltrimethylammonium bromide (CTAB). Cylindrical CTAB micelles formed during evaporation of the solvent acted as a structure directing template, forming nanometer-sized one-dimensional pores within the silica films. SMT experiments were performed using a wide-field fluorescence microscope that was sufficiently sensitive to allow detection of the fluorescence from individual dye molecules. A series of perylene diimide (PDI) dyes was employed for basic structural characterization of the silica materials. Single molecule fluorescence was recorded in the form of fluorescence videos. These videos revealed the presence of immobile dye molecules, along with those diffusing in one and two dimensions (1D and 2D). The 1D diffusing molecules provided basic evidence for the confinement mass transport of the dye molecules within the silica mesopores. Spectroscopic single molecule tracking (sSMT) studies served as an extension of basic SMT experiments and were employed to determine the location of the molecules. The polarity sensitive dye Nile Red (NR) was employed in these studies. It exhibits 1D diffusion, consistent with its confinement to the cylindrical pores, as was also the case for the PDI dyes. The sSMT data revealed that the majority of NR molecules were found in nonpolar environments having polarities similar to that of n-hexane. Single molecule emission polarization (SMEP) measurements were employed to explore the orientational confinement of the dyes. The results of these experiments demonstrated that the PDI and NR molecules diffuse with their long axes aligned parallel to the long axis of the pores. All of the dyes employed were found to be orientationally confined to ∼1 nm diameter pathways within the pores. The diffusion coefficient for the dyes was also shown to be ∼10^3 -fold smaller than in bulk solution. The results of the NR studies demonstrate that the dye molecules were confined to the hydrophobic cores of the micelles, and provide support for the conclusion that the PDI dyes are similarly confined. These studies afford an enhanced understanding of how nanostructuring of the pore-filling medium in solvent- and surfactant-filled mesoporous materials governs the mass transport and surface interactions of incorporated reagents and analytes. The dependence of molecular confinement on dye charge and structure was also explored in this dissertation. The confined translational and orientational motions of a series of four different PDI dyes diffusing along one dimension (1D) within individual cylindrical silica mesopores were investigated in these studies. Specifically, the motions of cationic and anionic PDI dyes were compared to those of two uncharged PDIs having different alkane tail lengths. All four dyes exhibited populations that were immobile, along with separate populations that diffused in either 1D or 2D. The anionic and cationic PDI dyes exhibited the largest and smallest populations, respectively, of immobile molecules, suggesting that electrostatic interactions between the charged dyes and the cationic surfactant head groups play a significant role in limiting molecular motion. The cationic and anionic PDI dyes also exhibit the largest populations of 2D diffusing molecules, suggesting they may more readily pass between the cylindrical micelles and through the silica pore walls. All four dyes also emit strongly polarized fluorescence as they move in 1D, indicating they are orientationally confined within the nanochannels. Nile Red dye was used to determine the dielectric constant, ε, of nonpolar microenvironments in double-stranded DNA (ds-DNA) single molecules both in aqueous buffer solution and when adsorbed on amine-modified chemical gradient surfaces. The value of ε within the DNA decreased with increasing buffer concentration. Values of ε ∼ 6.75 and ∼3.00 were obtained in 0.1 mM phosphate buffered saline (PBS) and in 10 mM PBS, respectively. Similar effects were observed upon adsorption to chemically graded amine-modified silica surfaces. Under 1 mM buffer, ε was measured to be ∼2.84 and ∼1.90 at the low amine (high silica), and high amine (low silica) ends of the gradient, respectively. An increase in the buffer concentration again led to a decrease in ε, but only at the low amine end. It is concluded that high buffer concentrations and binding to an amine surface cause condensation of the ds-DNA, forming less polar microenvironments within its structure. These results provide important knowledge of the factors governing the polarity of DNA microenvironments to which intercalators bind.

Dans le Modèle Standard de la physique des particules, la théorie de l’interaction forte, la chromodynamique quantique (QCD), est une théorie de jauge de groupe de symétrie SU (Nc) par rapport au nombre quantique de couleur. QCD obéit à la propriété de liberté asymptotique, permettant le calcul d’observables physiques à haute énergie en utilisant la QCD perturbative (pQCD). Cette thèse traite de la description en pQCD des taux de production de hadrons dans les collisions hadroniques à haute énergie, en vue d’applications à la phénoménologie des collisions proton-noyau et noyau-noyau dans les collisionneurs de hadrons (RHIC, LHC), où des effets nucléaires (shadowing, perte d’énergie partonique, élargissement de l’impulsion transverse) entrent en jeu. Dans une première partie, j’étudie l’élargissement de l’impulsion transverse d’un système de partons énergétiques traversant un noyau, en mettant l’accent sur la structure de couleur du processus. Un cadre théorique basé sur le formalisme des dipôles est utilisé, et une équation cinétique est dérivée pour la distribution en impulsion transverse de la paire de partons, en demandant que cette paire soit dans un état de couleur donné (représentation irréductible de SU (Nc)) à la fois dans l’état initial et dans l’état final. La structure de couleur est codée dans un opérateur d’évolution de couleur, qui est obtenu pour tout type de paire de partons. Pour une paire compacte de petite taille, la dérivation donne une interprétation physique claire du processus d’élargissement de l’impulsion transverse. Dans une deuxième partie, je discute la matrice de dimension anormale Q, qui est formellement analogue à l’opérateur d’évolution précédent, et qui apparaît lors de l’ étude du rayonnement de gluons mous associé à une diffusion partonique dure 2 −> 2. Il a été remarqué que la matrice Q associée à gg −> gg a une symétrie surprenante (reliant les degrés de liberté externe et interne). J’ai développé des outils pour dériver les matrices Q associées à des diffusions 2 −> 2 impliquant des partons généralisés, afin d’explorer si la symétrie observée pour gg −> gg est fortuite ou non. / In the Standard Model of particle physics,the theory of the strong interaction, Quantum Chromodynamics (QCD), is a gauge theory of symmetry group SU (Nc) with respect to the color quantum number. QCD obeys the property of asymptotic freedom, allowing the computation of high-energy physical observables using perturbative QCD (pQCD). This thesis deals with the pQCD description of hadron production rates in high-energy hadronic collisions, in view of applications to the phenomenology of proton-nucleus and nucleus-nucleus collisions at hadron colliders (RHIC,LHC), where so-called nuclear effects (shadowing, parton energy loss, transverse momentum broadening) come into play. In a first part, I study the transverse broadening of an energetic parton system crossing a nucleus, putting emphasis on the color structure of the process. A theoretical setup based on the dipole formalism is used,and a kinetic equation is derived for the parton pair transverse momentum distribution, requiring the parton pair to be in a given color state (SU (Nc) irreducible representation) both in the initial and final state. The color structure is encoded in a color evolution operator, which is obtained for any type of parton pair. For a small-size compact pair, the derivation yields a transparent physical interpretation of the pair transverse broadening process. In a second part, I discuss the soft anomalous dimension matrix Q, which is formally analogous to the previous evolution operator, and which appears when studying soft gluon radiation associated to 2 −> 2 hard parton scattering. It has been noticed that the Q-matrix associated to gg −> gg has a surprising symmetry (relating external and internal degrees of freedom). I developed tools to derive the Q-matrices associated to2 −> 2 scatterings involving generalized partons, in order to explore if the symmetry observed for gg −> gg is fortuitous or not.

Molibdatos têm atraído grande atenção devido à existência de compostos com caráter elétrico unidimensional como conseqüência da presença de cadeias contendo ligações de Mo-O ou Mo-Mo em suas estruturas cristalinas. Com o objetivo de estudar molibdatos com esta característica, amostras policristalinas do sistema K-Mo-O foram preparadas pelo método de reação de difusão no estado sólido e caracterizadas por difratometria de raios x, propriedades elétricas e magnéticas. Estes resultados demonstram a existência de uma nova fase neste sistema com estequiometria KxMoO2-&#948;. Medidas da resistência elétrica em função da temperatura deste material mostram comportamento metálico anômalo que está relacionado a um ordenamento antiferromagnético. Foi observado ainda que a anomalia na resistência elétrica em baixas temperaturas (T < TM) comporta-se segundo uma lei de potência com expoente próximo de 0,5, o que sugere que o comportamento elétrico do KxMoO2-&#948; pode ser descrito por um mecanismo de condutividade unidimensional. / Molybdates have attracted great attention due to the existence of compounds which show one-dimensional electrical behavior as consequence of the channel containing Mo-O or Mo-Mo bonds in their crystalline structure. In order to study molybdates exhibiting onedimensional conductivity, polycrystalline samples of the K-Mo-O system were prepared using the solid state diffusion reaction method and characterized by X-ray powder diffractometry, electrical and magnetic properties. These results demonstrate the existence of a new phase in this system with KxMoO2-&#948; stoichiometry. Electrical resistance as a function of temperature measurements for this compound have shown anomalous metallic behavior which is related to an antiferromagnetic ordering. It has been also observed that the anomaly in the electrical resistance at low temperatures (T < TM) is fitted by power law temperature dependence with an exponent near 0.5 which suggests that the electrical behavior of the KxMoO2-&#948; can be well described by the one-dimensional conducting mechanism.

Métodos de suavização através de processos de difusão é frequentemente utilizado como etapa prévia em diferentes procedimentos em imagens. Apesar da difusão anômala ser um processo físico conhecido, ainda não é aplicada à suavização de imagens como a difusão clássica. Esta dissertação propõe e relata a implementação e avaliação de filtros de difusão anômala, tanto isotrópico quanto anisotrópico, como um método de melhoramento em imagens ponderadas em difusão (DWI) e imagens de tensor de difusão (DTI) dentro do imageamento por ressonãncia magnética (MRI). Aqui propõe-se generalizar a difusão anisotrópica e isotrópica com o conceito de difusão anômala em processamento de imagens. Como metodologia implementou-se computacionalmente as equações de difusão bidimensional e aplicou às imagens MRI para avaliar o seu potencial como filtro de melhoramento. Foram utilizadas imagens de ressonância magnética de aquisição DTI em voluntários saudáveis. Os resultados obtidos neste estudo foram a verificação que métodos baseados em difusão anômala melhoram a qualidade em processamento das imagens DTI e DWI quando observadas medidas de qualidade como a relação sinal ruído (SNR) e índice de similaridade estrutural (SSIM), e assim determinou-se parâmetros ótimos para as diferentes imagens e situações que foram avaliadas em função dos seus parâmetros de controle, em especial o parâmetro anômalo, chamado de q. Os resultados apresentados aqui permitem prever não apenas uma melhora na qualidade das imagens DTI e DWI resultantes do processamento proposto, como também possível redução de repetições na sequência de aquisição de MRI para um SNR predeterminado. / Smoothing methods through diffusion processes is often used as a preliminary step in different procedures in images. Although the anomalous diffusion is a known physical process, it is not applied to image smoothing as the classical diffusion. This paper proposes and describes implementation and evaluation of anomalous diffusion filters, both isotropic and anisotropic, as a method of improving on diffusion-weighted images (DWI) and diffusion tensor images (DTI) within the magnetic resonance imaging (MRI). Hereby is proposed to generalize the isotropic and anisotropic diffusion with the concept of anomalous diffusion in image processing. The methodology is implemented computationally as bidimensional diffusion equations and applied to MRI images to evaluate its potential as a filter for quality improvement. We used DTI and DWI imaging to acquire from healthy volunteers as image set. The results of this study verified that methods based on anomalous diffusion improved DWI and DTI image processing when observed quality measures such as signal to noise ratio (SNR) and structural similarity index (SSIM), and determined filter optimal parameters for different images and situations evaluated in terms of their control parameters, particularly the anomalous parameter, called q. The results presented here can predict not only an improvement in the quality of DWI and DTI images resulting from the proposed method, and additionally the possible reduction of repetitions following acquisition of MRI for a predetermined SNR.