Phase-sensitive magnetic resonance (MR) imaging has a number of important clinical applications, such as phase-sensitive inversion recovery (PSIR) and Dixon water/fat imaging. PSIR and Dixon techniques are widely used in neurological and body imaging to improve tissue-contrast, the former by extending the dynamic range of image intensity and the later by suppressing unnecessary fat signals. Several important limitations, however, occur in these techniques: (1) Dixon techniques cannot decompose two signals if the resonance frequencies are close. For example, in MR mammography, it is difficult to separate silicone breast implants signals (4.0 ppm) from fat signals (3.5 ppm); (2) the signal dynamic range of images acquired using Dixon techniques is limited by the equilibrium magnetization; and (3) long image acquisition time. These limitations have hindered the applications of phase-sensitive Dixon imaging techniques on breast implant imaging or as a screening tool where fast acquisition is required. In this work, novel phase-sensitive MRI techniques were developed to enhance the capability, image-contrast, and scan-efficiency of Dixon imaging techniques. Specifically, we developed (1) a generalized chemical-shift imaging technique to separate spectrally overlapped signals both T1-contrast and chemical-shift; (2) a contrast-enhanced Dixon technique to extend the signal dynamic range of Dixon images; and (3) a single-echo acquisition (SEA) imaging technique integrated with phase-sensitive MR imaging to provide ultra-fast image acquisitions. Phantom studies, performed on 1.5 T and 4.7 T MR scanners, demonstrated the developed generalized chemical-shift imaging technique could clearly separate breast silicone implant signals (4.0 ppm) from fat (3.5 ppm). The contrast-enhanced Dixon technique, by extending the dynamic range of signal intensity from positive levels to positive/negative levels, could improve image-contrast by 1.6 times, compared with a conventional single-point Dixon technique. Phantom studies, using a 64-channel SEA imaging system, showed the integrated Dixon technique with SEA could acquire decomposed 2-D water-only and fat-only images with ultra-fast frame-rates up to 1/TR, while providing improved image-contrast (by 2.4 times in this experiment) compared with a conventional SEA imaging technique.

Phase-sensitive magnetic resonance (MR) imaging has a number of important clinical applications, such as phase-sensitive inversion recovery (PSIR) and Dixon water/fat imaging. PSIR and Dixon techniques are widely used in neurological and body imaging to improve tissue-contrast, the former by extending the dynamic range of image intensity and the later by suppressing unnecessary fat signals. Several important limitations, however, occur in these techniques: (1) Dixon techniques cannot decompose two signals if the resonance frequencies are close. For example, in MR mammography, it is difficult to separate silicone breast implants signals (4.0 ppm) from fat signals (3.5 ppm); (2) the signal dynamic range of images acquired using Dixon techniques is limited by the equilibrium magnetization; and (3) long image acquisition time. These limitations have hindered the applications of phase-sensitive Dixon imaging techniques on breast implant imaging or as a screening tool where fast acquisition is required. In this work, novel phase-sensitive MRI techniques were developed to enhance the capability, image-contrast, and scan-efficiency of Dixon imaging techniques. Specifically, we developed (1) a generalized chemical-shift imaging technique to separate spectrally overlapped signals both T1-contrast and chemical-shift; (2) a contrast-enhanced Dixon technique to extend the signal dynamic range of Dixon images; and (3) a single-echo acquisition (SEA) imaging technique integrated with phase-sensitive MR imaging to provide ultra-fast image acquisitions. Phantom studies, performed on 1.5 T and 4.7 T MR scanners, demonstrated the developed generalized chemical-shift imaging technique could clearly separate breast silicone implant signals (4.0 ppm) from fat (3.5 ppm). The contrast-enhanced Dixon technique, by extending the dynamic range of signal intensity from positive levels to positive/negative levels, could improve image-contrast by 1.6 times, compared with a conventional single-point Dixon technique. Phantom studies, using a 64-channel SEA imaging system, showed the integrated Dixon technique with SEA could acquire decomposed 2-D water-only and fat-only images with ultra-fast frame-rates up to 1/TR, while providing improved image-contrast (by 2.4 times in this experiment) compared with a conventional SEA imaging technique.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Áreas de Preservação Permanente (APPs) configuram áreas protegidas, cobertas ou não por vegetação nativa, legalmente estabelecidas em lei. Estas possuem funções ambientais que se integram entre si e se associam às suas diferentes categorias. O trabalho objetivou a adaptação do sistema de indicadores PEIR (pressão, estado, impacto, resposta) para avaliação ambiental integrada de APPs, com aplicação na sub-bacia do rio Saracuruna, RJ. Especificamente visou: a) Levantamento da legislação pertinente às APPs inseridas no contexto do uso e ocupação do solo e gestão ambiental integrada; b) Delimitação das faixas de APP, segundo os parâmetros definidos pelo Código Florestal para cada categoria existente na área; c) Seleção de indicadores ambientais relacionados às APPs delimitadas considerando suas diversas categorias e funções ambientais associadas; d) Avaliação do potencial e limitações da aplicação de indicadores de avaliação integrada em APPs, envolvendo a espacialização das informações com suporte de geotecnologias, com enfoque para a legitimação/intervenções nas faixas inseridas na sub-bacia em estudo. Metodologicamente envolveu a pesquisa bibliográfica, compreendendo o levantamento de todo o arcabouço jurídico ambiental pertinente às APPs e das referências de cartas de indicadores; a caracterização física e humana da sub-bacia, subsidiando a delimitação e pré-avaliação de APPs; a seleção de indicadores ambientais voltados à avaliação integrada de APPs, a aplicação, com o suporte de geotecnologias, de parte destes indicadores estruturados em ciclos PEIR frente à hierarquização, exemplificativa, das funções ambientais por grupo de categorias de APPs; e, por fim, a elaboração de mapas-síntese da situação das faixas de APP ligadas à drenagem e ao relevo de altitude, com enfoque na legitimação das mesmas. A revisão das políticas específicas e transversais às APPs e de seus planos incidentes atestou uma ampla base para a gestão local ou compartilhada destas faixas, no entanto, a delimitação de APPs em função da realidade local ainda não ocorre. A Carta-síntese de indicadores de avaliação integrada de APPs na sub-bacia contemplou um conjunto de quarenta indicadores, dentre os quais vinte e seis compuseram dois ciclos aplicados e seis ciclos parcialmente aplicados. Para as APPs ligadas à drenagem e ao relevo de altitude foram aplicados, respectivamente, os indicadores de: a) pressão: Alteração de áreas naturais por áreas antrópicas e Evolução da área urbana em encostas; b) estado: Impermeabilização do solo e Qualidade ambiental das terras; c) impacto: Áreas críticas de inundação e Áreas de risco de escorregamentos ou desmoronamentos; e d) resposta: Plano de bacia hidrográfica e Áreas de risco recuperadas. Tais ciclos atestaram a precisão dos indicadores de pressão e estado quando da avaliação sobre a preservação em APPs, porém não foram capazes de explicar isoladamente a causa de impactos, os quais não ocorrem de maneira exclusiva nestas faixas. Demonstraram ainda um nível maior de antropização em APPs localizadas na porção de baixada da sub-bacia, principalmente em margens de rios. Sendo assim, cabem ações voltadas à fiscalização de APPs legitimadas, à recuperação de faixas com baixa interferência humana, e às intervenções urbanísticas ou prioritárias em áreas degradadas ou impactadas / Permanent Preservation Areas (PPAs) configure protected areas, covered or not by native vegetation, legally established by law. These areas have environmental functions that integrate with each other and are associated with their different categories. The study aimed the adaptation of the system of PSIR indicators (pressure, state, impact, and response) for integrated environmental evaluation of PPAs, with application in the sub basin of river Saracuruna, RJ. Specifically aimed: a) Survey of relevant legislation about PPAs, inserted in the context of the use and occupation of land and integrated environmental management; b) Delimitation of strip of PPAs, according to parameters defined by Brazilian Forest Code for each categorie in the area; c) Selection of environmental indicators related to the delimited PPAs considering its various categories and associated environmental functions; d) Evaluation of the potential and limitations of application of indicators of integrated evaluation in PPAs, involving the spatialisation of the information supported by Geotechnology, with a focus in the legitimization/interventions of the strips of PPAs on the subbasin under study. Methodologically involved the bibliographical research, including the survey of all the relevant environmental and legal framework about PPAs and the collect of the reference of letters of indicators, the physical and human characteristics of the subbasin, supporting the delimitation and pre-assessment of its PPAs; the selection of environmental indicators focused on integrated assessment of PPAs; the application, supported by geotechnology, of part of these indicators structured in PSIR cycles in view of the, exemplary, hierarchization of environmental functions by category group of PPAs; and, finally, the development of mapssynthesis of the situation of the bands of PPAs connected to the drainage and the relief of altitude, with a focus on legitimizing this bands. The review of specific and cross-cutting policies to PPAs and their incident plans testified a broad base for local or shared management of these bands, however, the delimitation of the PPAs depending on the local conditions does not exist yet. The letter-synthesis of indicators of integrated evaluation of PPAs in the subbasin included a set of 40 (forty) indicators, of which 26 (twenty-six) composed 2 (two) applied cycles and 6 (six) partially applied cycles. For the APPs related to drainage and relief of altitude were applied, respectively, indicators: a) pressure: Change of natural areas to disturbed areas and Evolution of urban area on slopes b) state: Waterproofing of soil and Environmental quality of the land; c) impact: Critical areas of flooding and Areas of risk of landslides or mudslides; and d) response: Basin plan and Risk areas recovered. Such cycles have attested to the accuracy of indicators of pressure and state in the evaluation of the preservation in PPAs, but were not able to explain alone the cause of impacts, which do not occur exclusively in these bands. Also showed a higher level of human disturbance in PPAs located in the lowland portion of the subbasin, especially on river banks. Therefore, actions that aim the supervision of legitimized PPAs are appropiate, as well as action that aimed the recovery of tracks with low human interference and the urban or priority interventions in degraded or impacted areas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Áreas de Preservação Permanente (APPs) configuram áreas protegidas, cobertas ou não por vegetação nativa, legalmente estabelecidas em lei. Estas possuem funções ambientais que se integram entre si e se associam às suas diferentes categorias. O trabalho objetivou a adaptação do sistema de indicadores PEIR (pressão, estado, impacto, resposta) para avaliação ambiental integrada de APPs, com aplicação na sub-bacia do rio Saracuruna, RJ. Especificamente visou: a) Levantamento da legislação pertinente às APPs inseridas no contexto do uso e ocupação do solo e gestão ambiental integrada; b) Delimitação das faixas de APP, segundo os parâmetros definidos pelo Código Florestal para cada categoria existente na área; c) Seleção de indicadores ambientais relacionados às APPs delimitadas considerando suas diversas categorias e funções ambientais associadas; d) Avaliação do potencial e limitações da aplicação de indicadores de avaliação integrada em APPs, envolvendo a espacialização das informações com suporte de geotecnologias, com enfoque para a legitimação/intervenções nas faixas inseridas na sub-bacia em estudo. Metodologicamente envolveu a pesquisa bibliográfica, compreendendo o levantamento de todo o arcabouço jurídico ambiental pertinente às APPs e das referências de cartas de indicadores; a caracterização física e humana da sub-bacia, subsidiando a delimitação e pré-avaliação de APPs; a seleção de indicadores ambientais voltados à avaliação integrada de APPs, a aplicação, com o suporte de geotecnologias, de parte destes indicadores estruturados em ciclos PEIR frente à hierarquização, exemplificativa, das funções ambientais por grupo de categorias de APPs; e, por fim, a elaboração de mapas-síntese da situação das faixas de APP ligadas à drenagem e ao relevo de altitude, com enfoque na legitimação das mesmas. A revisão das políticas específicas e transversais às APPs e de seus planos incidentes atestou uma ampla base para a gestão local ou compartilhada destas faixas, no entanto, a delimitação de APPs em função da realidade local ainda não ocorre. A Carta-síntese de indicadores de avaliação integrada de APPs na sub-bacia contemplou um conjunto de quarenta indicadores, dentre os quais vinte e seis compuseram dois ciclos aplicados e seis ciclos parcialmente aplicados. Para as APPs ligadas à drenagem e ao relevo de altitude foram aplicados, respectivamente, os indicadores de: a) pressão: Alteração de áreas naturais por áreas antrópicas e Evolução da área urbana em encostas; b) estado: Impermeabilização do solo e Qualidade ambiental das terras; c) impacto: Áreas críticas de inundação e Áreas de risco de escorregamentos ou desmoronamentos; e d) resposta: Plano de bacia hidrográfica e Áreas de risco recuperadas. Tais ciclos atestaram a precisão dos indicadores de pressão e estado quando da avaliação sobre a preservação em APPs, porém não foram capazes de explicar isoladamente a causa de impactos, os quais não ocorrem de maneira exclusiva nestas faixas. Demonstraram ainda um nível maior de antropização em APPs localizadas na porção de baixada da sub-bacia, principalmente em margens de rios. Sendo assim, cabem ações voltadas à fiscalização de APPs legitimadas, à recuperação de faixas com baixa interferência humana, e às intervenções urbanísticas ou prioritárias em áreas degradadas ou impactadas / Permanent Preservation Areas (PPAs) configure protected areas, covered or not by native vegetation, legally established by law. These areas have environmental functions that integrate with each other and are associated with their different categories. The study aimed the adaptation of the system of PSIR indicators (pressure, state, impact, and response) for integrated environmental evaluation of PPAs, with application in the sub basin of river Saracuruna, RJ. Specifically aimed: a) Survey of relevant legislation about PPAs, inserted in the context of the use and occupation of land and integrated environmental management; b) Delimitation of strip of PPAs, according to parameters defined by Brazilian Forest Code for each categorie in the area; c) Selection of environmental indicators related to the delimited PPAs considering its various categories and associated environmental functions; d) Evaluation of the potential and limitations of application of indicators of integrated evaluation in PPAs, involving the spatialisation of the information supported by Geotechnology, with a focus in the legitimization/interventions of the strips of PPAs on the subbasin under study. Methodologically involved the bibliographical research, including the survey of all the relevant environmental and legal framework about PPAs and the collect of the reference of letters of indicators, the physical and human characteristics of the subbasin, supporting the delimitation and pre-assessment of its PPAs; the selection of environmental indicators focused on integrated assessment of PPAs; the application, supported by geotechnology, of part of these indicators structured in PSIR cycles in view of the, exemplary, hierarchization of environmental functions by category group of PPAs; and, finally, the development of mapssynthesis of the situation of the bands of PPAs connected to the drainage and the relief of altitude, with a focus on legitimizing this bands. The review of specific and cross-cutting policies to PPAs and their incident plans testified a broad base for local or shared management of these bands, however, the delimitation of the PPAs depending on the local conditions does not exist yet. The letter-synthesis of indicators of integrated evaluation of PPAs in the subbasin included a set of 40 (forty) indicators, of which 26 (twenty-six) composed 2 (two) applied cycles and 6 (six) partially applied cycles. For the APPs related to drainage and relief of altitude were applied, respectively, indicators: a) pressure: Change of natural areas to disturbed areas and Evolution of urban area on slopes b) state: Waterproofing of soil and Environmental quality of the land; c) impact: Critical areas of flooding and Areas of risk of landslides or mudslides; and d) response: Basin plan and Risk areas recovered. Such cycles have attested to the accuracy of indicators of pressure and state in the evaluation of the preservation in PPAs, but were not able to explain alone the cause of impacts, which do not occur exclusively in these bands. Also showed a higher level of human disturbance in PPAs located in the lowland portion of the subbasin, especially on river banks. Therefore, actions that aim the supervision of legitimized PPAs are appropiate, as well as action that aimed the recovery of tracks with low human interference and the urban or priority interventions in degraded or impacted areas

L’émergence des réseaux sociaux a révolutionné le Web en permettant notamment aux individus de prolonger leur connexion virtuelle en une relation plus réelle et de partager leurs connaissances. Ce nouveau contexte de diffusion de l’information sur le Web peut constituer un moyen efficace pour cerner les besoins en information des utilisateurs du Web, et permettre à la recherche d’information (RI) de mieux répondre à ces besoins en adaptant les modèles d’indexation et d’interrogation. L’exploitation des réseaux sociaux confronte la RI à plusieurs défis dont les plus importants concernent la représentation de l’information dans un modèle social personnalisé de RI et son évaluation, en l’absence de collections de test et de compétitions dédiées. Nous proposons dans ce travail de bénéficier de l’exploitation des informations issues des réseaux sociaux pour personnaliser la recherche d’information de l’utilisateur en se rapprochant le plus de ses centres d’intérêt et de ses préférences. Les principales contributions de notre travail consistent dans un premier temps à établir un profil social de l’utilisateur à partir du contenu informationnel généré au sein du réseau social. Nous présentons par la suite des modèles de recherche sociale personnalisée d’information (RSPI) permettant d’intégrer le profil social de l’utilisateur à différents niveaux du processus de RI. Dans l’objectif de permettre l’évaluation des modèles de RSPI sur une collection de test dédiée, nous proposons une collection de test de RSPI que nous avons construite à partir du réseau d’annotation collaborative "Delicious" contenant en plus des données classiques d’une collection de test de RI, des données centrées-utilisateur / The emergence of social media has revolutionized the web by allowing individuals to extend their virtual connection in a more real relationship and share knowledge. This new context of information dissemination on the Web can be an effective way to identify the information needs of Web users, and allow information retrieval (IR) to better meet these needs by adapting the indexing and querying models. The information retrieval faced several challenges with the use of social networks, the most important concerns the representation of information in a personalized social IR (PSIR) model and its evaluation in the absence of a social test collections with the user-centered data (user-centered queries and user-centered relevance judgments). We propose to benefit from the use of the user generated content (UGC) on the social networks to personalize his social search in order to better fit his interests and preferences. The main contributions of our work consist of, on the one hand, building a social profile from the UGC within the social network. We propose then a personalized social information retrieval models which integrate the user’s social profile at various levels of the IR process. On the other hand, with the objective of evaluating our PSIR models on a dedicated test collection, we propose a PSIR test collection "DelRSI" we built from the collaborative social bookmarking network "Delicious" ; a PSIR test collection containing in addition to the classical IR test collection’s data, a user-centered data