Estudamos as restrições impostas pelo princípio da covariância sobre o procedimento de quantização em espaços planos e curvos. Mostramos que o conjunto de todas as quantizações covariantes em espaços planos em coordenadas retangulares é composto de ordenamentos de operadores de posição e momento e exibimos uma parametrização funcional deste conjunto. Deduzimos regras para a quantização covariante em espaços planos em coordenadas gerais. Generalizamos estas quantizações para espaços curvos e mostramos que nestes espaços, além da ambiguidade de ordenamento, surge uma nova ambiguidade relacionada à curvatura. Este novo tipo de ambiguidade explica o surgimento de uma classe grande de potenciais quânticos no problema da quantização de uma partícula não relativística em um espaço curvo. / We study the restrictions imposed by the covariance principle on the quantization procedure in flat and curved spaces. We show that the set of all covariant quantizations in flat spaces in rectangular coordinates is composed of position and momentum operator orderings and exhibit a functional parametrization of this set. We deduce rules for the covariant quantization in flat spaces in general coordinates. We generalize these quantizations for curved spaces and show that in such spaces, besides the ordering ambiguity, it appears a new ambiguity related to the curvature. This new kind of ambiguity explains the appearence of a wide class of quantum potentials in the problem of quantization of a non-relativistic particle in curved space.

Les jets sont des phénomènes d’éjection collimatée de plasma magnétisé. Ces ph́énomènes liés à l’accrétion d’un disque sur un objet central, sont relativement répandus dans l’univers : les environnement des étoiles jeunes (objets Herbig-Haro, étoiles T Tauri), des binaires X, des sursauts gamma et les noyaux actifs de galaxies... Les jets extra-galactiques sont issus des trous noirs super-massifs au centre de galaxies telles que les quasars ou les radiogalaxies. Ils sont caractérisés par leur taille, leur puissance et la vitesse du plasma.Les jets extragalactiques sont étudiés dans de ce travail de thèse, même si les outils et méthodes développés peuvent être utilisés pour les binaires X et les micro-quasars. Nous poserons en particulier les questions des mécanismes de lancement, d’accélération et de collimation de ces écoulements. Nous traiterons également de la source énergétique à l’origine de l’écoulement qui peut atteindre une puissance de l’ordre de 10^47 erg.s−1.Le liens avec l’accrétion, la proximité de la base des jets avec le trou noir central, les vitesses d’écoulement observées dans certains jets, montrent que le traitement de ces questions doit inclure les effets de la relativité générale. Nous étudierons donc des solutions de la décomposition 3+1 des équations de la magnéto-hydrodynamique en métrique de Kerr. Nous nous appliquerons au développement d’un modèle d’écoulement méridional auto-similaire avec un traitement consistant du cylindre de lumière. Ce modèle pouvant s’appliquer à la fois au jet et à l’accrétion. Nous explorons les mécanismes d’accélération et de collimation des solutions produites. Nous calculerons des solutions de l’écoulement entrant dans l’horizon et de l’écoulement sortant à l’infini incluant des termes d’injection de paires. Le rôle du mécanisme de création de paires et des processus d’extraction de l’énergie du trou noir sera exploré. / Jets are collimated ejection phenomena of magnetized plasma. These phenomena related to the accretion of a disk on a central object, are relatively common in the universe: the environment of young stars (Herbig- Haro Objects, T Tauri stars...), X-ray binaries, Gamma-ray-bursts, and active galactic nuclei... Extragalactic jets come from super-massive black holes in the center of galaxies such as quasars or radiogalaxies. They are characterized by their size, their power and velecity of the plasma.Extragalactic jets will be the subject of studies in this thesis work, although the tools and methods developed can be used for X-ray binaries and microquasars. In particular, we will ask questions about the mechanisms of launching, accelerating and collimating these flows, but also about the energy source at the origin of the flow that can reach a power in the order of 10^47erg.s−1.The links with the accretion, the proximity of the jet base to the central black hole, flow velocities observed in some jets, show that the treatment of these issues must include the effects of general relativity. We will therefore study solutions of the 3+1 decomposition of magneto-hydrodynamic equations in Kerr metric. We will apply ourselves the development of a meridional self-similar magnetized flow model with a consistent treatment of the light cylinder effect. This model can be applied to both spine jet and accretion. We explore the mechanisms of acceleration and collimation of the obtained solutions. We will calculate solutions of the incoming flow in the horizon and the outgoing flow reaching infinity including injection terms. The role of the pair creation mechanism and the processes of extracting energy from the black hole are explored.

The present-day interest in gravitational waves, justified by the recent direct detections made by LIGO, is opening the exciting possibility to answer many questions regarding General Relativity in extreme situations. One of these questions is whether black hole are – indeed – described totally by their mass, charge and angular momentum or whether they can have additional long-range hair. This project is concerned with this question. We aim at studying the influence of additional structure on the black hole horizon in the form of long-range hair by studying linearized Einstein equation the solutions when perturbed. More precisely, we will study the Schwarzschild solution, pierced by an infinitely long and thin cosmic string such that the space-time possesses a global deficit angle. Quasi-normal modes are believed to dominate the gravitational wave emission during the ring down phase of an excited black hole that would e.g. be the result of a merger of two ultra-compact objects, therefore linearized perturbations can be considered. With the advent of gravitational wave astronomy the proposed study will be very important when reconstructing the source of the detected gravitational wave signals. / O atual interesse em ondas gravitacionais, justificado pelas detecções diretas feitas pela colaboração LIGO recentemente, está abrindo a excitante possibilidade de responder várias questões a respeito da Relatividade Geral em condições estremas. Uma dessas questões é se buracos negros são – realmente – totalmente discritos apenas por sua massa, carga e momento angular ou se eles podem ter os chamados cabelos de longo alcance adicionais. Nosso projeto se preocupa em responder esta pergunta. Nosso objetivo está em estudar a influência de uma estrutura adicional no horizonte de eventos de um buraco negro através do comportamento da equação linearizada de Einstein quando a solução é perturbada. Mais precisamente, nós estudaremos a solução de Schwarzschild atravessada por uma corda cósmica infinitamente fina, tal corda faz com que o espaço-tempo tenha um hiato angular em seu plano equatorial. Acredita-se que modos quasi-normais dominem a emissão de ondas gravitacionais durante a fase de ringing down de buracos negros excitados que podem, por exemplo, se originar da colisão de objetos ultra compactos, portanto perturbações lineares podem ser consideradas. Com o advento da astronomia através de ondas gravitacionais o estudo proposto será importante para que se possa reconstruir a origem de sinais detectados.

In this thesis, we present a collection of newly obtained results concerning the existence of vanishing viscosity solutions to the one-dimensional compressible Euler equations of gas dynamics, with and without geometric structure. We demonstrate the existence of such vanishing viscosity solutions, which we show to be entropy solutions, to the transonic nozzle problem and spherically symmetric Euler equations in Chapter 4, in both cases under the simple and natural assumption of relative finite-energy. In Chapter 5, we show that the viscous solutions of the one-dimensional compressible Navier-Stokes equations converge, as the viscosity tends to zero, to an entropy solution of the Euler equations, again under the assumption of relative finite-energy. In so doing, we develop a compactness framework for the solutions and approximate solutions to the Euler equations under the assumption of a physical pressure law. Finally, in Chapter 6, we consider the Euler equations in special relativity, and show the existence of bounded entropy solutions to these equations. In the process, we also construct fundamental solutions to the entropy equations and develop a compactness framework for the solutions and approximate solutions to the relativistic Euler equations.

The diploma thesis is concerned with the effect of the grammatical gender of Czech nouns referring to inanimate entities on their semantic meaning and conceptualization. The thesis looks into the question whether masculines are conceptulized as "men" and feminines as "women". The thesis is divided into two main parts. In the first part, theoretical insight into the question of relation between language and thought is provided. In this part, foreign experiments related to our research question are mentioned as well. In the second part, two experiments accomplished in the Czech language are presented. The objective of experiment nr. 1 was to choose such semantic differential scales which according to Czech speakers distinguish the "female and male principle" the best. In experiment nr. 2, feminine and masculine gender variants of nouns were employed (e. g. "brambor - brambora"). Experiment nr. 2 contained two tasks. The first task used the semantic differential method. In the second task, participants were asked to choose a woman's or a man's voice that the inanimate entities would have in a cartoon movie. The results of the first task indicate that the grammatical gender of nouns did not affect the decision-making as individual nouns were marked on the semantic differential scales. However, there...

Esta dissertação teve por objeto delinear alguns fatores relativos ao processo de emergência da leitura dos trabalhos do linguista e antropólogo norte-americano Edward Sapir (1884-1939) como um dos proponentes de um conjunto de afirmações acerca da natureza das línguas naturais, agrupadas sob o rótulo relativismo linguístico, cujo debate recebeu bastante atenção dos antropólogos linguistas estadunidenses, na primeira metade do século XX. Costuma-se afirmar que o relativismo linguístico seja uma hipótese, que alega que a língua pode moldar a percepção da realidade, o pensamento ou a cultura. Visto o nome de Sapir estar associado ao de Whorf, como o rótulo hipótese Sapir-Whorf indica, e que este rótulo tem sido bastante utilizado atualmente para se referir ao relativismo linguístico, efetuou-se o rastreamento de alguns conceitos fundamentais nesta discussão, dentro do quadro teórico proposto por Sapir, tal como suas concepções acerca da língua, da cultura e do pensamento, com vistas a avaliar a procedência de sua recepção como um relativista. Havido sido este trabalho conduzido sob a metodologia da Historiografia Linguística, buscamos também resgatar os fatores contextuais nos quais tais proposições teóricas emanaram. Por fim, propomos a discussão da configuração do termo relativismo no horizonte teórico do autor, visando fornecer uma perspectiva de leitura diferente da proposta, atualmente, por inúmeros manuais de História da Linguística. / This dissertation had as its objective to outline some factors related to the emergence process of reading the American anthropologist and linguist Edward Sapirs (1884- 1939) papers as one of the proponents of a set of assertions about the nature of natural languages, grouped under the label linguistic relativity, whose debate received much attention from American linguistic anthropologists, during the first half of the twentieth century. It is often said that the linguistic relativity is a hypothesis, which argues that language can shape the perception of reality, thought or culture. Since Sapirs name has been associated with Whorfs, as the label Sapir-Whorf hypothesis indicates, a term widely used today to refer to linguistic relativity, we carried out tracking of some fundamental concepts in this discussion, within the theoretical framework proposed by Sapir, as his conceptions of language, culture and thought, in order to assess the merits of its reception as a relativist. As this research was conducted under the methodology of Linguistic Historiography, we have also sought to rescue the contextual factors in which such theoretical propositions have emanated. Finally, we propose to discuss the setting of the term relativism in the author\'s theoretical horizon, aiming to provide a reading perspective fairly different from the ones proposed currently by numerous handbooks on the History of Linguistics.

Motion events are ubiquitous in conversation, from describing a tiresome commute to recounting a burglary. These situations, where an entity changes location, consist of four main semantic components: Motion (the movement), Figure (the entity moving), Ground (the object or objects with respect to which the Figure carries out the Motion) and Path (the route taken). Two additional semantic components can occur simultaneously: Manner (the way the Motion occurs) and Cause (the source of/reason for the Motion). Languages differ in preferences for provision and packaging of semantic components in descriptions. It has been suggested, in the thinking-for-speaking hypothesis, that these preferences influence the conceptualisation of events (such as their memorisation). This thesis addresses questions relating to the description and memory of Motion events in British Sign Language (BSL) and English. It compares early BSL (acquired before age seven) and late BSL (acquired after age 16) descriptions of Motion events and investigates whether linguistic preferences influence memory. Comparing descriptions by early signers and late signers indicates where their linguistic preferences differ, providing valuable knowledge for interpreters wishing to match early signers. Understanding how linguistic preferences might influence memory contributes to debates around the connection between language and thought. The experimental groups for this study were: deaf early BSL signers, hearing early BSL signers, deaf late BSL signers, hearing late BSL signers and hearing English monolinguals. Participants watched target Motion event video clips before completing a memory and attention task battery. Subsequently, they performed a forced-choice recognition task where they saw each target Motion event clip again alongside a distractor clip that differed in one semantic component. They selected which of the two clips they had seen in the first presentation. Finally, participants were filmed describing all of the target and distractor video clips (in English for English monolinguals and BSL for all other groups). The Motion event descriptions were coded for the inclusion and packaging of components. Linguistic descriptions were compared between languages (English and BSL) and BSL group. Statistical models were created to investigate variation on the memory and attention task battery and the recognition task. Results from linguistic analysis reveal that English and BSL are similar in the components included in descriptions. However, packaging differs between languages. English descriptions show preferences for Manner verbs and spatial particles to express Path ('run out'). BSL descriptions show preferences for serial verb constructions (using Manner and Path verbs in the same clause). The BSL groups are also similar in the components they include in descriptions. However, the packaging differs, with hearing late signers showing some English-like preferences and deaf early signers showing stronger serial verb preferences. Results from the behavioural experiments show no overall relationship between language group and memory. I suggest that the similarity of information provided in English and BSL descriptions undermines the ability of the task to reveal memory differences. However, results suggest a link between individual linguistic description and memory; marking a difference between components in linguistic description is correlated with correctly selecting that component clip in the recognition task. I argue that this indicates a relationship between linguistic encoding and memory within each individual, where their personal preference for including certain semantic components in their utterances is connected to their memory for those components. I also propose that if the languages were more distinct in their inclusion of information then there may have been differences in recognition task scores. I note that further research is needed across modalities to create a fuller picture of how information is included and packaged cross-modally and how this might affect individual Motion event memory.

L'objectif de cette thèse est d'étudier différents aspects microscopiques et macroscopiques liés à la présence de superfluidité dans les étoiles à neutrons. Dans un premier temps, nous avons calculé des configurations stationnaires d'étoiles à neutrons superfluides en rotation, en relativité générale, basées sur l'utilisation d'équations d'état réalistes. A l'aide de ces configurations d'équilibre, nous avons ensuite développé un modèle simple de glitch, en relativité générale, vu comme un transfert de moment cinétique entre les neutrons superfluides et les particules chargées constituant l'étoile. Cela nous a permis d'obtenir des temps caractéristiques de montée qui pourront être comparés à de futures observations précises de glitches afin d'apporter de meilleures contraintes sur l'intérieur de ces étoiles. Enfin, nous nous sommes également intéressés à la dynamique des vortex superfluides, en présence de tubes de flux, dans le cas où les protons dans le coeur des étoiles formeraient un supraconducteur de type II. / The aim of this thesis is to study different aspects, both microscopic and macroscopic, associated with the presence of a large amount of superfluid matter inside neutron stars. First, we computed stationary configurations of rotating superfluid neutron stars, in general relativity, using realistic equations of state. Based on these equilibrium configurations, we then developed a simple model of pulsar glitches, in general relativity, seen as angular momentum transfers between the superfluid neutrons and the charged particles composing the star. This enables us to infer spin-up time scales that could be compared with future accurate glitch observations, in order to get some constraints on the interior of neutron stars. Finally, we also focused on the dynamics of superfluid vortex lines, accounting for the presence of fluxtubes, if the protons are forming a type II superconductor in the core of neutron stars.

Desde o início do uso de ferramentas computacionais na química, pesquisadores notaram a necessidade de um adequado tratamento da correlação eletrônica para a acurada descrição da estrutura eletrônica. Algum tempo depois, perceberam que, além da correlação, haviam ainda deficiências nos resultados obtidos, as quais estavam relacionadas com efeitos relativísticos, principalmente quando tentavam tratar moléculas com átomos pesados. Um terceiro aspecto a ser levado em consideração nestes estudos diz respeito ao uso de um conjunto acurado de funções de base. No caso específico de cálculos relativísticos, se possível, tais conjuntos ainda precisam garantir a eliminação do prolapso variacional, um problema que está relacionado com uma descrição deficiente da região mais próxima dos núcleos. Com esse propósito, o conjunto RPF-4Z foi desenvolvido recentemente. Sendo assim, este projeto foi voltado para a análise comparativa da qualidade do conjunto RPF-4Z. Desta forma, foram avaliadas propriedades fundamentais das moléculas como, por exemplo, geometrias, momentos de dipolo e constantes espectroscópicas. Simultaneamente, uma propriedade desafiadora, o gradiente de campo elétrico na posição de núcleos de xenônio, também foi considerada. Os resultados obtidos até agora reforçam a eficiência do conjunto RPF-4Z, que é capaz de fornecer valores comparáveis àqueles dados por conjuntos de base de mesma qualidade, mas com menor demanda por recursos computacionais. / Early in the application of computational framework in chemistry, researchers noticed the need for an adequate electronic correlation treatment in order to accurately describe electronic structures. Some years later they realized that, besides correlation, there were also deficiencies in the results, which were related to relativistic effects, especially when dealing with molecules containing heavy atoms. A third aspect to be taken into account is related to the use of an accurate basis set. Specifically for relativistic calculations, these basis sets must also ensure the elimination of variational prolapse if possible, which is a problem related to a poor description of the innermost region close to the nuclei. Thus, the RPF-4Z basis set was recently developed for this aim. This project is focused on a comparative analysis regarding the RPF-4Z basis set\'s quality. Thereby, fundamental properties of molecules were evaluated, such as geometries, dipole moments and spectroscopic constants. At the same time, a challenging property, the electric field gradient at the xenon nuclei, was considered as well. The results obtained so far reinforce the efficiency of the RPF-4Z basis set, which is capable of providing comparable values to those obtained by same quality basis sets but with a lower demand for computational resources.

Some of the brightest and most energetic events in the Universe are associated with the death of stars. These stellar deaths power transient electromagnetic emission which are routinely observed on Earth. This dissertation presents our research on various such transients. Its topics includes, supernova remnants, kilonovae, gamma-ray bursts (GRBs): The "long'' type produced from core-collapse supernovae and the "short'' type associated with neutron star merger events. It also focuses on the disruption of stars by the tidal forces of supermassive black holes i.e., tidal disruption events (TDEs). We model the emission from these transients and compare them to observations in order to draw a number of conclusions and make predictions for future detections. For example, we find that the non-thermal emission from supernovae and kilonovae associated with GRBs can produce long term emission which may be detected as a re-brightening in the overall emission. The sharp cut off observed in some TDE flares can be caused by a pre-existing accretion disk present around a supermassive black hole, which is expected in active galactic nuclei. Our work successfully predicted the nature of the very first electromagnetic detection from a neutron star merger, and was able to reproduce the emission that had been observed for more than one hundred days after the merger. This dissertation also provides frameworks on how the observable features of these transients can be leveraged to probe the properties of the progenitor system and their environment. <br>