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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

La bande interstellaire diffuse "GAIA" : optimisation de son extraction et de son utilisation à double but stellaire et interstellaire / The Diffuse Interstellar Band "GAIA" : optimisation of its extraction and use with double stellar and interstellar goal

Capitanio, Letizia 29 November 2018 (has links)
Le milieu interstellaire (ISM) représente un fraction mineur de la matière de la Voie Lactée, mais joue un rôle clefs dans l'évolution et la structure galactique. La majorité des constituants du ISM a été identifiée grâce à leur émissions ou absorptions, mais une catégorie d'absorption, les "bandes interstellaires diffuses" (DIBs), n'ont pas des particules absorbantes identifiées. En particulier, il y a une DIB centrée à 862 nm dans le intervalle spectroscopique du Radial Velocity Spectrometer (RVS), un des instruments des la mission ESA Gaia. La première partie de ma thèse est reliée à la construction de ce future catalogue et son usage potentiel. J'ai développé un code de profile fitting adapté à la DIB "Gaia" et à l'instrument RVS. Je présente dans ma thèse l'estimation de DIB mesurable.La second partie de ma thèse est en relation aux cartes 3D du ISM. J'ai focalisé sur l'usage potentiel des DIBs pour le mapping. J'ai fait la première tomography basée sur des données composées, extinction et DIB. J'ai tourné des inversions parallèles des extinctions et DIB pour les mêmes targets stellaires, et comparé les distributions. J'ai développé une technique exprès pour le massive dataset, appelée "technique topographique hiérarchique" et j'ai appliqué cet technique aux nouveau catalogue de 30 millions des mesures d'extinction basé sur Gaia. Finalement, j'ai utilisé des spectres au sol pour extraire soit les vitesses soit la colonne des matériaux interstellaire avec du profile-fitting et j'ai participé aux premiers steps d'une carte cinématique 3D du ISM. / The Interstellar Medium (ISM) represents a small fraction of the Milky Way matter, but it plays a fundamental role because it governs the galactic evolution and its structure.Most of the ISM gaseous constituents have been identified through their emission or absorption characteristics, however, the "diffuse interstellar bands" (or DIBs), still has no counterpart in absorbing species.A favourable situation is the presence of a DIB (with central wavelength 862 nm) within the spectral interval of the Radial Velocity Spectrometer (RVS), one of the instruments of the ESA Gaia mission. The first part of the work presented in this document is directly related to the construction of this future catalog and its potential use.I have developed a profile fitting code adapted to the emph{Gaia} DIB and to the RVS instrument. I estime in my thesis how many DIBs will be measured.The second part of this thesis is related to the three-dimensional (3D) mapping of the ISM. I made the first tomography based on composite data, both extinctions and DIBs and showed this is a viable way. I ran parallel inversions of two extinction and DIB datasets for the same target stars and compared the distributions.The full 3D tomographic inversion technique in this case requires an unrealistically large computing time. I have developed a technique and I have applied it to a new catalog of 30 millions of extinction measurements based on Gaia.Finally, I used ground-based stellar spectra to extracted radial velocities and columns of IS absorbing species and participated to the first step of a "kinematic" 3D map of the ISM.
2

A habitação social e a intervenção municipal : o caso de Vila Nova de Gaia

Violas, Débora Amélia Reis de Oliveira January 2003 (has links)
Com este trabalho pretende-se analisar as formas de intervenção da administração central e local no domínio da habitação social. Num primeiro momento, faz-se uma referência histórica às políticas definidas e implementadas para identificar as condições que propiciaram ou dificultaram a promoção de habitação para as classes de fracos recursos. Num segundo momento é abordado o papel dos municípios, como agentes de desenvolvimento, e da sua intervenção no campo habitacional, em função das competências que foram adquirindo após 25 de Abril de 1974. De seguida faz-se análise aos problemas associados aos processos de realojamento. Posteriormente procede-se a um levanatmento das características da evolução da população residente e dos alojamentos na Área Metropolitana do Porto. Por fim, analisa-se a intervenção municipal, em Vila Nova de Gaia, no âmbito da promoção habitacional assim como acções desenvolvidas a nível social e de equipamentos, aspectos essenciais para que o realojamento seja um meio para o desenvolvimento da integração social.
3

Gaia : an analysis of the critical literature with an emphasis on the philosophical and spiritual implications of the hypothesis /

Jacobs, Liza. January 1991 (has links) (PDF)
Thesis (M. Env. Sc.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1993. / Includes bibliographical references.
4

Escassos caminhos : os processos de imobilização social dos beneficiários do R.M.G. em Vila Nova de Gaia

Rodrigues, Eduardo Vítor January 2006 (has links)
No description available.
5

Gaia : an analysis of the critical literature with an emphasis on the philosophical and spiritual implications of the hypothesis

Jacobs, Liza. January 1991 (has links) (PDF)
Includes bibliographical references.
6

Gaia : de la validation des données aux paramètres du Red Clump / Gaia : from the data validation to the Red Clump parameters

Ruiz-Dern, Laura 08 November 2016 (has links)
La mission Gaia de l'Agence Spatiale Européenne (ESA) a pour objectif de cartographier notre galaxie avec une précision astrométrique jamais atteinte auparavant. Il est donc particulièrement important que les données qui seront publiées soient rigoureusement validées afin d'assurer une qualité optimum au Catalogue. Ces validations sont faites par l'une des équipes de l'unité de coordination CU9 du Consortium Gaia DPAC (Data Processing and Analys Consortium) chargé par l'ESA de la production du Catalogue Gaia. Dans le cadre de cette thèse, nous avons mis en place toute l’infrastructure nécessaire à la validation du catalogue Gaia par comparaison avec des catalogues externes. Celle-ci gère toutes les interactions avec l'environnement global des validations et avec la base de données Gaia. Ensuite nous avons développé un ensemble de tests statistiques pour valider les données du premier catalogue Gaia (DR1). Ces tests concernent notamment l’homogénéité des données sur le ciel, la qualité des positions et de la photométrie de l'ensemble des étoiles de DR1 (plus d'un milliard d'étoiles, $V<20$) ainsi que celle des parallaxes et mouvements propres des étoiles de textit{Tycho-Gaia} Astrometric Solution (TGAS), environ deux millions d'étoiles communes aux catalogues Gaia et Tycho-2 ($V<12$). Ces tests statistiques sur la DR1 sont opérationnels et ont déjà été appliqués très récemment sur des données préliminaires. Cela a déjà permis d'améliorer ces données (donc la qualité du catalogue), et d'en caractériser les propriétés statistiques. Cette caractérisation est essentielle à une exploitation scientifique correcte des données. Le premier catalogue Gaia sera publié à la fin de l’été 2016. Parmi les objets observés par Gaia, il y a une population d'étoiles particulièrement intéressantes, les étoiles du Red Clump (RC), très utilisées comme étalons de distance. Nous avons développé et testé deux méthodes pour modéliser les relations couleur-couleur (CC) et température effective - couleur dans toutes les bandes photométriques, de l'ultraviolet au proche-infrarouge. Elles permettront de caractériser le RC dans la bande G de Gaia dès la publication du catalogue: 1. en utilisant des modèles théoriques, et 2. empiriquement, en se basant sur une méthode Monte Carlo Markov Chain (MCMC). Pour cela nous avons très rigoureusement sélectionné des échantillons d'étoiles avec une bonne qualité photométrique, une bonne métallicité, déterminée par spectroscopie, une température effective homogène et une faible extinction interstellaire. À partir de ces calibrations CC et température-couleur, nous avons ensuite développé une méthode par Maximum de Vraisemblance qui permet de déterminer les magnitudes absolues, les températures et les extinctions des étoiles du RC. Les couleurs et extinctions ainsi obtenues ont été testées sur des étoiles avec des températures effectives mesurées spectroscopiquement et une extinction déterminée par la mesure des Bandes Diffuses Interstellaires (DIB). Ces propriétés intrinsèques des étoiles du RC vont permettre de caractériser le Red Clump Gaia et de calibrer, dans la bande Gaia, la magnitude absolue de cet étalon de distance, premier échelon essentiel de la détermination des distances dans l'Univers. / The Gaia mission of the European Space Agency (ESA) aims to map our galaxy with an unprecedented astrometric precision. It is therefore very important that the data that will be published be rigorously validated to ensure an optimal quality in the Catalogue. These validations are done by one of the teams of the coordination unit CU9 of the Gaia DPAC Consortium (Data Processing and Analysis Consortium) commissioned by ESA of the Gaia catalogue production. As part of this thesis, we implemented all the necessary infrastructure to validate the Gaia catalogue by comparison with external catalogues. This last manages all the interactions with the global environment of validations and with the Gaia database. Then we developed a set of statistical tests to validate the data from the first Gaia catalogue (DR1). These tests relate in particular to the homogeneity of data on the sky, the quality of the positions and of photometry of all the stars of DR1 (more than a billion stars, $V <20$) as well as that of the parallaxes and proper motions for textit{Tycho-Gaia} Astrometric Solution (TGAS) stars, around two million stars in common in Gaia and Tycho-2 catalogues ($V <12$).These DR1 statistical tests are operational and were already applied very recently on preliminary data. This has improved the data (thus the quality of the catalog) as well as allowed to characterize the statistical properties. This characterisation is essential for a correct scientific exploitation of the data. The first Gaia catalogue will be released in late summer 2016.Among the objects that Gaia observes, there is a population of stars particularly interesting, the Red Clump (RC) stars, widely used for distance indicators. We developed and tested two methods to model the colour-colour (CC) and effective temperature - colour relations in all photometric bands, from the ultraviolet to the near infrared. They will allow us to characterize the RC in the Gaia G band upon publication of the catalogue: 1. using theoretical models, and 2. empirically, based on a Monte Carlo Markov Chain (MCMC) method. For this we have very carefully selected samples of stars with a good photometric quality, good metallicity determined by spectroscopy, an homogeneous effective temperature and a low interstellar extinction.From these CC and temperature-colour calibrations, we then developed a Maximum Likelihood method that allows to derive absolute magnitudes, temperatures and extinctions of the RC stars. Estimates of colours and extinctions are tested on stars with spectroscopically measured effective temperatures and an extinction determined by the measurement of Diffuse Interstellar Bands (DIB). These intrinsic properties of RC stars will allow to characterize the Gaia RC and calibrate, within the Gaia G band, the absolute magnitude of this standard candle, first essential step of determining distances in the Univers.
7

Space astrometry of unresolved binaries: From Hipparcos to Gaia/Astrometrie spatiale des binaires non-resolues: D'Hipparcos a Gaia

Pourbaix, Dimitri 13 September 2007 (has links)
Building upon its success with the Hipparcos space astrometry mission launched in 1989, the European Space Agency has agreed to fund the construction of its successor, Gaia, and its launch in 2011. Despite the similarities between the two missions, Gaia will be orders of magnitude more powerful, more sensitive, but also more complex in terms of data processing. Growing from 120,000 stars with Hipparcos to about 120,000E4 stars with Gaia does not simply mean pushing the computing resources to their limits (1 second of processing per star yields 38 years for the whole Gaia-sky). It also means facing situations that did not occur with Hipparcos either by luck or because those cases were carefully removed from the Hipparcos Input Catalogue. This manuscript illustrates how some chunks of the foreseen Gaia data reduction pipeline can be trained and assessed using the Hipparcos observations. This is especially true for unresolved binaries because they pop up so far down in the Gaia pipeline that, by the time they get there, there is essentially no difference between Hipparcos and Gaia data. Only the number of such binaries is different, going from two thousand to ten million. Although the computing time clearly becomes an issue, one cannot sacrifice the robustness and correctness of the reduction pipeline for the sake of speed. However, owing to the requirement that everything must be Gaia-based (no help from ground-based results), the very robustness of the reduction has to be assessed as well. For instance, the underlying assumptions of some statistical tests used to assess the quality of the fits used in the Hipparcos pipeline might no longer hold with Gaia. That may not affect the fit itself but rather the quality indicators usually accompanying those fits. For the final catalogue to be a success, these issues must be addressed as soon as possible.
8

Projeto de uma ponte em arco entre as ribeiras do Porto e Gaia

Calisto, Pedro Miguel da Silva January 2011 (has links)
No description available.
9

Eleições autárquicas 2009 : campanha eleitoral Coligação Gaia Na Frente

Correia, Joana Filipa Costa January 2010 (has links)
Este trabalho consiste num relatório sobre o estágio efectuado no âmbito do mestrado de Ciências da Comunicação, na campanha eleitoral da Coligação Gaia Na Frente para as eleições autárquicas de 2009. No relatório é descrito o trabalho realizado durante a campanha eleitoral e faz-se o contraponto da teoria com a prática,
10

A praia de Miramar e o litoral de Gaia : contributo para o conhecimento da sua evolução urbanística

Silva, Ana Cristina Baeta Serra de Campos January 2001 (has links)
Pretende-se aprofundar e sistematizar os conhecimentos sobre a evolução urbanística do litoral de Gaia, em particular sobre a praia de Miramar. A informação recolhida permitiu avaliar a dinâmica dessa evolução, as suas causas e efeitos mais mercantes em termos especiais e as relações estabelecidas com as dinâmicas de lazer e turismo da área. A pesquisa incidiu fundamentalmente sobre documentação existente em arquivos públicos, e o intervalo de tempo situa-se entre os primeiros anos do século XX e a década de 70 do mesmo século.

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