Este trabalho apresenta um estudo sobre a viabilidade de utilização do protocolo conservativo CMB para sincronização de simulações distribuídas em diferentes plataformas MIMD com memória distribuída, utilizando granulosidade grossa com poucos processos paralelos. A técnica utilizada para a realização das análises consiste em efetuar coleta de dados na execução da simulação de um grande número de modelos. Para a simulação desses modelos foi desenvolvida, e é apresentada neste trabalho, a extensão funcional ParSMPL, que implementa o protocolo de sincronização CMB. Pode-se subdividir os resultados obtidos com a análise dos dados das simulações em enfoques que apresentam contribuições distintas. O primeiro enfoque avalia como a plataforma adotada e o modelo a ser simulado influenciam no speedup alcançado. Neste caso, define-se quando uma aplicação tem tendência a ser eficiente com o paradigma da simulação distribuída utilizando o protocolo CMB. O segundo enfoque refere-se à necessidade do usuário conhecer a melhor forma de se utilizar a simulação distribuída. A partir das análises realizadas foi estabelecido um conjunto de diretrizes que visam auxiliar o processo de desenvolvimento de uma simulação distribuída conservativa. Com a ajuda dessas diretrizes e a disponibilidade da extensão ParSMPL espera-se auxiliar o usuário a desenvolver aplicações eficientes utilizando o paradigma da simulação distribuída conservativa, sem exigir desse usuário o conhecimento das características e particularidades do protocolo de sincronização utilizado / This thesis approaches a study about the viability of using the CMB conservative protocol for distributed simulation synchronization on different distributed memory M vID platforms and considering coarse granularity and few parailel processes. The technique used to analyze the results comprises data acquisition during simulation execution for a large number of models. The simulation of these models is performed on a special-built distributed simulation environment (ParSMPL) developed and presented in this work, being a CMB synchronization protocol implementation. The results obtained in this work are split according to different views taking to distinct sets of contributions. The first view evaluates the influence of the model and the execution platform on the speedup reached. In this case it is defined when an application can reach efficiency through the adoption of the distributed simulation paradigm using the CMB protocol. The second view refers to the need of the users knowing the best way to make use of distributed simulation. Thus, following the analysis performed in this thesis, it is established a set of procedures to help in the distributed simulation development process adopting the conservative approach. By following the procedures proposed and using the ParSMPL an user can hope precious help in the development of efficient conservative distributed sirnulation programs, without the need of knowing the features and particularities of the CMB protocol

Este trabalho apresenta um estudo sobre a viabilidade de utilização do protocolo conservativo CMB para sincronização de simulações distribuídas em diferentes plataformas MIMD com memória distribuída, utilizando granulosidade grossa com poucos processos paralelos. A técnica utilizada para a realização das análises consiste em efetuar coleta de dados na execução da simulação de um grande número de modelos. Para a simulação desses modelos foi desenvolvida, e é apresentada neste trabalho, a extensão funcional ParSMPL, que implementa o protocolo de sincronização CMB. Pode-se subdividir os resultados obtidos com a análise dos dados das simulações em enfoques que apresentam contribuições distintas. O primeiro enfoque avalia como a plataforma adotada e o modelo a ser simulado influenciam no speedup alcançado. Neste caso, define-se quando uma aplicação tem tendência a ser eficiente com o paradigma da simulação distribuída utilizando o protocolo CMB. O segundo enfoque refere-se à necessidade do usuário conhecer a melhor forma de se utilizar a simulação distribuída. A partir das análises realizadas foi estabelecido um conjunto de diretrizes que visam auxiliar o processo de desenvolvimento de uma simulação distribuída conservativa. Com a ajuda dessas diretrizes e a disponibilidade da extensão ParSMPL espera-se auxiliar o usuário a desenvolver aplicações eficientes utilizando o paradigma da simulação distribuída conservativa, sem exigir desse usuário o conhecimento das características e particularidades do protocolo de sincronização utilizado / This thesis approaches a study about the viability of using the CMB conservative protocol for distributed simulation synchronization on different distributed memory M vID platforms and considering coarse granularity and few parailel processes. The technique used to analyze the results comprises data acquisition during simulation execution for a large number of models. The simulation of these models is performed on a special-built distributed simulation environment (ParSMPL) developed and presented in this work, being a CMB synchronization protocol implementation. The results obtained in this work are split according to different views taking to distinct sets of contributions. The first view evaluates the influence of the model and the execution platform on the speedup reached. In this case it is defined when an application can reach efficiency through the adoption of the distributed simulation paradigm using the CMB protocol. The second view refers to the need of the users knowing the best way to make use of distributed simulation. Thus, following the analysis performed in this thesis, it is established a set of procedures to help in the distributed simulation development process adopting the conservative approach. By following the procedures proposed and using the ParSMPL an user can hope precious help in the development of efficient conservative distributed sirnulation programs, without the need of knowing the features and particularities of the CMB protocol

Low Noise Amplifiers (LNAs) are one of the most important components found in some of the radio receivers used in radio astronomy. A good LNA should simultaneously possess both a gain in excess of 25\,dB and as low a noise contribution as possible. This is because the gain is used to suppress the noise contribution of the subsequent components but the noise generated by the LNA adds directly to the noise of the overall receiver. The work presented in this thesis aimed to further enhance the noise performance through a variety of techniques with the aim of applying these techniques to the study of the polarisation of the Cosmic Microwave Background. One particular technique investigated was to cool the LNAs beyond the standard 20\,K typically used in experiments to 2\,K. In doing so it was found that the noise performance increased by between 20 and 30\% depending on the amplifier. Another technique investigated involved uniting the two technologies (MICs and MMIC) used in LNA fabrication to lower the noise performance of the LNA. Such an LNA, known as a T+MMIC LNA was successfully developed and possessed an average noise temperature of 9.4\,K and a gain in excess of 40\,dB for a 27-33\,GHz bandwidth at 8\,K physical temperature. Potential ``in field'' applications for these technologies are discussed, and a design for a variant of the T+MMIC LNA that utilises both of these technologies is presented. This particular LNA with a predicted average noise temperature of 6.8\,K for a 26-36\,GHz bandwidth, would if fabricated successfully represent the lowest noise Ka-band LNA ever reported.

No description available.

Cosmology is one of the best tools to understand the physics that governs the universe at high energies. On one hand, inflation is a very robust mechanism to explain the initial conditions of the universe. On the other hand general relativity provides a solid framework for the formation of cosmic structures at cosmological scales. Nevertheless, there are still important issues that remain without a clear answer. For example, inflation still lacks of a concrete microphysical description, and also there is still no satisfactory mechanism to explain the late time acceleration of the universe. This thesis addresses these two topics. In the first part we discuss the effects of heavy degrees of freedom coupled to inflation. This has been an important topic over the years, because the experimental success might make it possible to detect new degrees of freedom in inflation. In chapter two we discuss the case when non relativistic heavy fields are coupled to the inflaton through a non minimal gravitational coupling. Here we find that, for certain geometries, the heavy field can modify the potential for a few e-folds, either stopping inflation, or setting its initial conditions. In chapter 3 we study the dynamics of fluctuations in holographic inspired models of multi-field inflation. We find that the entropy mass $\mu$ (the mass of the fluctuation orthogonal to the trajectory of inflation) satisfies an universal upper bound given by $\mu \leq 3 H / 2$. This bound coincides with the requirement of unitarity of conformal operators living on the boundary of the theory. In the second part of the thesis we study high energy effects on the Cosmic Microwave Background (CMB). In the fourth chapter we study the role of disformal transformation on cosmological backgrounds and its relation to the speed of sound for tensor modes. A speed different from one for tensor modes can arise in several contexts such as Galileons theories, or massive gravity. Nevertheless the speed is very constrained to be one by observations of gravitational wave emission. It has been shown that in inflation a disformal transformation allows the speed for tensor modes, to be set to one without making changes to the curvature power spectrum. We show that on the CMB, after doing the transformation, there is an imprint on the acoustic peaks, and the diffusion damping. This has interesting consequences: for a particular class of theories the transformation can be used to constrain the parameter space in different regimes. In chapter five we study the impact of gravitons with non-vanishing masses on the polarisation of th CMB . We also focus on putative modifications to the speed of the gravitational waves. We find that a change of the graviton speed shifts the acoustic peaks of the B-mode polarization and then could be easily constrained. In all cases when both massless and massive gravitons are present, we find that the B-mode CMB spectrum is characterised by a low $l$ plateau together with a shifted position for the first few peaks compared to a massless graviton spectrum. This shift depends on the mixing between the gravitons in their coupling to matter and could serve as a hint in favour of the existence of multiple gravitons.

The timescape cosmology represents a potentially viable alternative to the standard homogeneous and isotropic Friedmann--Lemaître--Robertson--Walker (FLRW) cosmology, without the need for dark energy. This thesis first extends the previous work on the timescape cosmology to include a radiation component in the evolution equations for the timescape cosmology and tests of the timescape model are then performed against the Cosmic Microwave Background (CMB) temperature anisotropies from the Planck satellite. Although average cosmic evolution in the timescape scenario only differs substantially from that of FLRW cosmologies at relatively late epochs when the contribution from the energy density of radiation is negligible, a full solution of the Buchert equations to incorporate radiation is necessary to smoothly match parameters to the epoch of photon decoupling and to obtain constraints from CMB data. Here we have extended the matter-dominated solution found in earlier work to include radiation, providing series solutions at early times and an efficient numerical integration strategy for generating the complete solution. To analyse the spectrum of CMB anisotropies in the timescape cosmology we exploit the fact that the timescape cosmology is extremely close to the standard cosmology at early epochs and adapt existing numerical codes to produce CMB anisotropy spectra. To find a FLRW model that matches as closely as possible the timescape expansion history, we have studied and compared a number of matching methods. We perform Markov Chain Monte Carlo analyses on the timescape model parameter space, and fit CMB multipoles 50 ≤ l ≤ 2500 to the Planck satellite data. Parameter fits include a dressed Hubble constant, H₀ = 61.0 kms ⁻¹Mpc⁻¹ (±1.3% stat)(±8% sys), and a present void volume fraction fᵥ₀ = 0.627 (±2.3% stat)(±13% sys). In the timescape model this value of fᵥ₀ means that the galaxy/wall observer infers an accelerating universe, where the apparent acceleration is due to gravitational energy gradients and clock rate differences rather than some dark energy. We find best fit likelihoods which are comparable to that of the best fit ΛCDM cosmology in the same multipole range.

El bioetanol es un combustible complementario a las gasolinas, producido mediante fermentación de azúcares simples derivados de sacarosa, almidón o celulosa. Debido a su gran abundancia el material celulósico es particularmente atractivo como fuente de combustible. La hidrólisis de la celulosa puede realizase utilizando métodos químicos (ácidos o bases) o enzimáticos. La hidrólisis enzimática genera productos más puros y consume menos energía; sin embargo, debido a su bajo rendimiento se requiere usar grandes cantidades de enzima, lo cual eleva considerablemente los costos de producción. Las endoglucanasas son glicosil hidrolasas que rompen enlaces β-1,4 en polímeros de glucosa. Actúan sobre enlaces internos de la celulosa amorfa generando su despolimerización. La estructura de las celulasas incluye un módulo catalítico, unido a un dominio que actúa como centro de anclaje a la celulosa, por lo que se le ha denominado Modulo de Unión a Carbohidrato (CBM por su sigla en Inglés). Estudios previos han demostrado que una alta afinidad a celulosa se correlaciona con un aumento en la hidrólisis de ésta. En el presente trabajo se proponen mutaciones en el CBM de la endo β-1,4 glucanasa de Trametes versicolor (TvEG), que aumenten la adsorción de la enzima sobre celulosa, buscando de este modo aumentar la hidrólisis de ésta. Se generó un modelo tridimensional del CBM de la endoglucanasa de T. versicolor mediante modelación comparativa. La estructura obtenida está formada por tres hojas beta antiparalelas unidas entre sí mediante dos puentes disulfuro. El modelo generado se utilizó para llevar a cabo estudios de Docking Molecular, para identificar regiones de interacción celulosa–CBM. Usando los resultados de la simulación computacional de la interacción CBM-celulosa, se identificaron dos zonas de unión. La primera concuerda con la reportada previamente para CBM’s de la familia I, mientras que no existen reportes en la literatura sobre interacción de la celulosa con la segunda zona identificada. A continuación se simuló mediante Docking Molecular, la interacción de celulosa con variantes de CBM que contenían diferentes aminoácidos en las posiciones clave de la segunda zona de interacción; los valores de energía libre de unión entregados por la simulación permitieron sugerir tres variantes de secuencia de CBM. Las variantes seleccionadas fueron: variante 1 (G7Y, F10W), variante 2 (G7Y, F10W, G12Q) y variante 3 (G7Y, G9Q, F10W, G12Q), donde G es glicina, Y tirosina, F fenilalanina, W triptófano y Q glutamina. Se generó un sistema de expresión recombinante de TvEG mediante clonamiento del gen silvestre de la enzima en el vector pET22b(+) y transformación en E. coli BL21(DE3); la proteína se acumuló intracelularmente en forma activa. Las mutaciones planteadas fueron construidas exitosamente mediante mutagénesis sitio dirigida, utilizando la metodología de mutación por extensión de superposición. De esta forma, se deja planteado un sistema de expresión recombinante de las variantes construidas, de modo de en el futuro cuantificar experimentalmente la adsorción de los CBM mutados y validar los resultados del análisis realizado in sílico. Se concluye que la estrategia utilizada permitió simular apropiadamente la interacción CBM-celulosa. Los resultados permitieron proponer en base a los estudios de DM, una estrategia de doble anclaje del CBM a celulosa, que si bien es cierto debe ser comprobado experimentalmente, resulta ser novedoso. Además, permitió proponer variantes del CBM de TvEG que potencialmente se adsorberán con mayor afinidad sobre celulosa. Si bien estas mutaciones deben ser validadas experimentalmente, fueron planteadas a partir de un diseño racional lo que aumentaría la probabilidad que éstas presenten mayor afinidad a celulosa.

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Humanas, Departamento de Antropologia, 1994. / Submitted by Jaqueline Ferreira de Souza (jaquefs.braz@gmail.com) on 2013-02-15T13:17:05Z No. of bitstreams: 1 1994_DorisAleidaVillamizarSayago.pdf: 4853210 bytes, checksum: e5ff6c2e4e516f875ae6211511a323c3 (MD5) / Approved for entry into archive by Jaqueline Ferreira de Souza(jaquefs.braz@gmail.com) on 2013-02-15T13:34:08Z (GMT) No. of bitstreams: 1 1994_DorisAleidaVillamizarSayago.pdf: 4853210 bytes, checksum: e5ff6c2e4e516f875ae6211511a323c3 (MD5) / Made available in DSpace on 2013-02-15T13:34:08Z (GMT). No. of bitstreams: 1 1994_DorisAleidaVillamizarSayago.pdf: 4853210 bytes, checksum: e5ff6c2e4e516f875ae6211511a323c3 (MD5) / Os Colégios Militares são instituições encarregadas da educação e re-socialização dos jovens alunos na vida militar e talvez, como em nenhum outro lugar, esta re-socialização se dê através do uso de uma disciplina que guarda relação intima com a reprodução da corporação militar. Procurei. compreender esta reprodução a partir de três segmentos existentes no Colégio Militar de Brasília: 1) professores militares, 2) professores civis e 3) os estudantes. Dentro de este ultimo segmento privilegiei os internos. Assim, o objetivo principal da pesquisa foi compreender o internato como locus privilegiado de reprodução da Ideologia militar. Igualmente se procurou compreender como se manifesta no dia-a-dia do internato, a disciplina militar enquanto mecanismo de controle e hierarquia. E o internato o lugar onde melhor pode-se identificar a maneira como a disciplina e implementada e como e transmitida. A análise das relações dos três principais segmentos mencionados enquanto agentes produtores, receptores e reprodutores de uma ideologia,, de valores e praticas., permite entender uma forma especifica de reprodução de uma instituição militar. / Los colegios ,militares son instituciones encargadas de la educación y resocialización de los jóvenes alumnos en la vida militar y quizás, como en ningún otro lugar, esta resocialización se dá a través del uso de una disciplina que guarda estrecha relación con la reproducción de la corporación militar. Intente comprender esa reproducción a parti de tres segmentos existentes en el Colegio militar de Brasília: 1) profesores militares, 2) profesores civiles e 3) los estudiantes. Dentro de este ultimo segmento destaque los internos. Así,el objetivo principal de la investigación fue comprender el internado tomo locus privilegiado de reproducción de la - ideología militar. Igualmente se busco comprender como se manifiesta en el dia-a-dia del internado, la disciplina militar como mecanismo de control y jerarquía. Es el internado el lugar donde mejor se puede identificar la manera como la disciplina es implementada y como es transmitida. El análisis de las relaciones de los tres principales segmentos mencionados como agentes productores, receptores e reproductores dos una ideologia, de valores y prácticas, permite entender una forma específica de reproducción de uma institución militar.

Cette thése est dédiée à la mesure des anisotropies du Fond Diffus Cosmologique (CMB) ainsi qu'à la caractérisation des émissions d'avant-plan galactiques. Les travaux que nous avons réalisés s'inscrivent dans le cadre de la préparation à l'analyse des données du satellite PLANCK. Cette thèse débute pas une description du modèle de Big Bang chaud et de la physique du CMB. Ensuite un état des lieux des expériences dédiées à la mesure du CMB est dressé, donnant lieu à la présentation des expériences Archeops, WMAP et PLANCK. Une deuxième partie est dédiée à la présentation des émissions galactiques diffuses puis à l'étude de ces émissions dans le plan galactique, permettant d'établir des cartes partielles des variations spatiales de la température des grains de poussière et des indices spectraux des émissions synchrotron et de poussière. Une troisième partie est dédiée à l'étude des deux principales émissions galactiques polarisées diffuses : les émissions synchrotron et de la poussière. Nous avons étudié des modèles effectifs de ces émissions basés sur l'utilisation de cartes-patron. Ensuite nous avons construit des modèles basés sur la physique de ces émissions et les avons comparés aux données Archeops et WMAP afin de contraindre les paramètres de ces modèles. Ceci nous permet de proposer pour la première fois un modèle cohérent de ces deux émissions. Ensuite nous fournissons une méthode pour améliorer ces contraintes à l'aide des données PLANCK. Dans une dernière partie nous étudions les spectres de puissance angulaires de ces émissions galactiques et estimons la contamination du signal CMB par ces émissions d'avant-plan. Enfin nous proposons une méthode pour minimiser la contamination du signal CMB de PLANCK par l'émission de la poussière.

Ce travail est concentré sur l'étude de la cosmologie primordiale et en particulier sur l'étude de l'inflation. Après une introduction sur la théorie standard du Big Bang, nous discutons de la physique du CMB et nous expliquons comment ses observations peuvent être utilisées pour définir des contraintes sur les modèles cosmologiques. Nous introduisons l'inflation et nous expliquons sa réalisation la plus simple. Nous présentons les observables et les contraintes expérimentales qui peuvent être utilisées pour mettre des contraintes sur les modèles d'inflation. La possibilité d'observer des ondes gravitationnelles primordiales (GW) produites au cours de l'inflation est examinée. Nous présentons les raisons pour définir une classification des modèles d'inflation et pour introduire le formalisme de la fonction 13 pour décrire l'inflation. En particulier nous expliquons pourquoi, dans ce cadre, nous pouvons naturellement définir un ensemble de classes d'universalité pour les modèles d'inflation. Les motivations théoriques pour soutenir la formulation de l'inflation en termes de ce formalisme sont présentées. Certains modèles généralisés d'inflation sont introduits et l'extension du formalisme de la fonction (3-formalisme à ces modèles est discutée. Enfin, nous nous concentrons sur l'étude des modèles où l’inflation (qui es assumé être pseudo-scalaire) est couplé non-minimalement à des champs de jauge abéliens qui peuvent être présents lors de l'inflation. L'analyse du problème est effectuée en utilisant une caractérisation de modèles d'inflation sur la base de leur comportement asymptotique. Un large éventail d'aspects théoriques et des conséquences d'observation est discuté. / This work is focused on the study of early time cosmology and in particular on the study of inflation. After an introduction on the standard Big Bang theory, we discuss the physics of CMB and we explain how its observations can be used to set constraints on cosmological models. We introduce inflation and we carry out its simplest realization by presenting the observables and the experimental constraints that can be set on inflationary models. The possibility of observing primordial gravitational wave (GW) produced during inflation is discussed. We present the reasons to deftne a classification of inflationary models and introduce the [3-function formalism for inflation by explaining why in this framework we can naturally define a set of universality classes for inflationary models. Theoretical motivations to support the formulation of inflation in terms of this formalism are presented. Some generalized models of inflation are introduced and the extension of the (3-function formalism for inflation to these models is discussed. Finally we focus on the study of models where the (pseudo-scalar) inflaton is non-minimally coupled to some Abelian gauge fields that can be present during inflation. The analysis of the problem is carried out by using a characterization of inflationary models in terms of their asymptotic behavior. A wide set of theoretical aspects and of observational consequences is discussed.