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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.
41

Formation of Polycyclic Aromatic Hydrocarbons and Nitrogen Containing Polcyclic Aromatic Compounds in Titan's Atmosphere, the Interstellar Medium and Combustion

Landera, Alexander 24 October 2013 (has links)
Several different mechanisms leading to the formation of (substituted) naphthalene and azanaphthalenes were examined using theoretical quantum chemical calculations. As a result, a series of novel synthetic routes to Polycyclic Aromatic Hydrocarbons (PAHs) and Nitrogen Containing Polycyclic Aromatic Compounds (N-PACs) have been proposed. On Earth, these aromatic compounds originate from incomplete combustion and are released into our environment, where they are known to be major pollutants, often with carcinogenic properties. In the atmosphere of a Saturn’s moon Titan, these PAH and N-PACs are believed to play a critical role in organic haze formation, as well as acting as chemical precursors to biologically relevant molecules. The theoretical calculations were performed by employing the ab initio G3(MP2,CC)/B3LYP/6-311G** method to effectively probe the Potential Energy Surfaces (PES) relevant to the PAH and N-PAC formation. Following the construction of the PES, Rice-Ramsperger-Kassel-Markus (RRKM) theory was used to evaluate all unimolecular rate constants as a function of collision energy under single-collision conditions. Branching ratios were then evaluated by solving phenomenological rate expressions for the various product concentrations. The most viable pathways to PAH and N-PAC formation were found to be those where the initial attack by the ethynyl (C2H) or cyano (CN) radical toward a unsaturated hydrocarbon molecule led to the formation of an intermediate which could not effectively lose a hydrogen atom. It is not until ring cyclization has occurred, that hydrogen elimination leads to a closed shell product. By quenching the possibility of the initial hydrogen atom elimination, one of the most competitive processes preventing the PAH or N-PAC formation was avoided, and the PAH or N-PAC formation was allowed to proceed. It is concluded that these considerations should be taken into account when attempting to explore any other potential routes towards aromatic compounds in cold environments, such as on Titan or in the interstellar medium.
42

Suporte à recuperação de imagens médicas baseadas em conteúdo através de Histogramas Métricos.

Josiane Maria Bueno 05 February 2002 (has links)
Os grandes centros médicos e hospitais de todo o mundo têm procurado integrar as informações de seus pacientes incluindo os exames de imagens efetuados (tomografia computadorizada, tomografia por ressonância magnética, ultrasson, medicina nuclear, etc.). Um sistema que integra as imagens junto às informações tradicionais é chamado de Sistema de Arquivamento e Comunicação de Imagens (Picture Archive and Communication System - PACS). Os sistemas PACS comerciais associam as imagens de exames às informações de pacientes através de chaves de consultas textuais e numéricas, não suportando consultas baseadas no conteúdo pictórico das imagens. Entretanto, muitas vezes o médico gostaria de recuperar as imagens armazenadas que fossem semelhantes (similares) a uma determinada imagem de consulta. Por exemplo, seja a consulta: "encontre as 10 imagens mais semelhantes à imagem Raio-X-tórax do Jõao da Silva". Ao responder a consultas desse tipo, o sistema permite que o médico relembre casos ocorridos anteriormente. Além disso, o conhecimento já gerado de exames e tratamentos anteriores pode ser recuperado mais rapidamente do que utilizando apenas a memória humana ou um sistema não automático de recuperação de informações. Um sistema com a capacidade de recuperar imagens utilizando o seu conteúdo pictórico é uma ferramenta valiosa para o auxílio ao diagnóstico médico. Esta tese apresenta a arquitetura de um PACS atualmente em desenvolvimento. Este sistema está sendo denominado mini-PACS. Tal sistema necessita da integração de três sistemas, a saber: - Um Sistema de Processamento de Imagens (SPI), o qual é responsável pela leitura e pré-processamento das imagens que são recebidas de diferentes dispositivos e possuem diferentes formatos. O SPI extrai as características relevantes das imagens, as quais serão utilizadas para a sua indexação e recuperação por conteúdo. - Um Sistema de Gerenciamento de Bases de Dados e Imagens (SGBDI), que permite a armazenagem e a recuperação de imagens baseada em seu conteúdo. O SGBDI utiliza uma estrutura métrica, a Slim-tree, que indexa as imagens através das características extraídas pelo SPI e possibilita responder consultas por similaridade. - Um Servidor de Web (SW), que disponibiliza o acesso às informações através da internet. A construção do Servidor de Web encontra-se fora do escopo do desenvolvimento desta tese. Porém, testes iniciais sobre a transferência e comunicação de imagens utilizando um servidor e aplicativos Java foram desenvolvidos para avaliar o comportamento do sistema. Entre as principais contribuições deste trabalho encontra-se um novo método de extração de características de imagens chamado histograma métrico. Os histogramas métricos permitem comparar imagens de diferentes tamanhos e mapeadas em faixas de quantização diferentes (se a alteração de brilho for linear). O tempo de resposta às consultas por similaridade utilizando histogramas métricos é, em média, 5 vezes menor do que o tempo de resposta utilizando histogramas tradicionais. Para permitir a indexação das imagens utilizando a Slim-tree foi necessário desenvolver uma nova função de distância métrica. Tal função de distância utiliza a diferença entre as áreas das curvas do histograma métrico. A construção da árvore de indexação utilizando os histogramas métricos chega a ser 10 vezes mais rápida do que com os histogramas tradicionais. As inovações e aperfeiçoamentos oriundos deste trabalho estão sendo integrados ao mini-PACS. Este sistema vem sendo desenvolvido de forma conjunta entre o Grupo de Bases de Dados e Imagens (GDBI) do Instituto de Ciências Matemáticas e de Computação da USP e o Centro de Ciências de Imagens e Física Médica (CCIFM) da Faculdade de Medicina de Ribeirão Preto da USP.
43

Regards croisés sur les unions conjugales : droit français - droit libyen / Marital unions, comparative study : French law and Libyan law

El Harari Al Shawesh, Assma 02 May 2016 (has links)
Le droit français et le droit libyen reposent sur des principes foncièrement différents. Le premier, fondé sur la laïcité, prône l'égalité homme-femme. Le second, de tradition religieuse n'est pas favorable à ce principe, la prédominance masculine en est le trait caractéristique. Cette distinction se voit tout au long de notre étude. Dans une première partie nous traitons les différentes formes de couples que connaissent les deux systèmes ainsi que les effets de nature aussi bien personnelle que patrimoniale qui en résultent. Cela comprend notamment l'exercice de l'autorité parentale et la contribution aux frais de ménage. Dans la seconde partie, il est question de la dissolution du couple et des conséquences qu'elle produit, personnelles comme patrimoniales. Malgré les différences entre les deux systèmes, on observe des difficultés de part et d'autre relatives à l'existence et à la dissolution du couple. Le système français est très attaché aux principes de liberté, égalité ; le système libyen est d'avantage protectionniste. D'une manière générale, les unions conjugales sont toujours le reflet d'une culture et des évolutions dans une société. / The author deals with different forms of marital unions in French and Libyan law. The main questions treated in the thesis are the consequences of marital life and its dissolution.
44

Evaluating Process Mining Techniques on PACS Command Usage Data : Exploring common process mining techniques and evaluating their applicability on PACS event log data for domain-specific workflow analysis

Ekblom, Axel, Karlén, Jacob January 2023 (has links)
Many software companies today collect command usage data by monitoring and logging user interactions within their applications. This is not always utilised to its full potential, but with the use of state-of-the-art process mining techniques, this command usage log data can be used to gain insights about the users' workflows. These insights can then be used to improve the software application and boost user productivity and efficiency. One area where this might be especially relevant is within the radiology domain, where the radiology labour shortage renders every efficiency-improvement valuable. Connected to this, this thesis aimed to evaluate a number of process mining techniques on real radiology PACS command usage data from Sectra to identify which techniques might be useful for analysing user workflows. Three process discovery algorithms (Alpha, Heuristics, and Inductive Miner - infrequent) were used on two datasets and evaluated based on a number of quantitative metrics (fitness and simplicity) and qualitative aspects (interpretability and usefulness). The qualitative aspects of the resulting process models were assessed through interviews with domain experts at Sectra, and the Heuristics Miner was found to discover the most useful models that could be interpreted and analysed by domain experts, mainly due to its simpler process model notation. To reduce model complexity, three different filtering methods based on sequential pattern mining were evaluated as a pre-processing step before applying the discovery algorithms. This resulted in improvements for the Alpha and Inductive Miner - infrequent, although none of the methods improved the Heuristic Miner models against the baseline. Trace clustering was also explored to address model complexity with the aim of identifying trace execution variants. Several configurations of trace representation techniques and clustering algorithms were used, and the neural-network-based approaches, Word2Vec and Autoencoder, emerged as the alternatives that achieved the best scores in the clustering evaluation. A few clusters with well-separated trace execution variants were identified - although most clusters were still complex and dominated by similar events. Finally, a prototype application with integrated process mining concepts was created based on the findings from the previous interviews. This was then evaluated with domain experts at Sectra, with the aim of investigating what concepts are practically useful for assisting with domain analysis. The findings indicate a clear use case for such an application to analyse sequential relations and command usage patterns in PACS user workflows, providing a data-driven and on-demand approach for hypotheses testing. Simpler concepts like manual filtering and aggregation were found to be practically useful and prioritised by the domain experts, while the opinion was more divided on the automatic pre-processing methods.
45

Extern granskning av medicinska bilder, framtidens lösning? / External analysis of medical images, an prospective solution?

Skibicki, Dominik, Pejhman, Pourmand January 2010 (has links)
No description available.
46

Extern granskning av medicinska bilder, framtidens lösning? / External analysis of medical images, an prospective solution?

Skibicki, Dominik, Pejhman, Pourmand January 2010 (has links)
No description available.
47

ARQUITETURA PARA RECUPERAÇÃO DE IMAGENS DIAGNÓSTICAS BASEADA EM CONTEÚDO: UMA FERRAMENTA PARA AUXÍLIO À RADIOLOGIA EM AMBIENTE PACS / ARCHITECTURE FOR CONTENT-BASED DIAGNOSTIC IMAGE RETRIEVAL: A TOOL TO AID IN RADIOLOGY PACS ENVIRONMENT

Berni, Cristiano Albiero 08 November 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / One of the main forms of diagnosis used nowadays matches the exams performed by analysis of diagnostic images. Due to a growing request for this kind of diagnostic and the repetitive manual procedure of the used methods by radiologists new ways are emerging to aid procedures. A tool that can help the physician to report a diagnosis is searching similar cases for that which is being held with the main function of increased safety to the radiologist in his notes. For this, a modular architecture for content-based diagnostic image retrieval was developed as a tool to aid diagnosis. Through the DICOM SR standard used to store radiological findings and measurements - commonly from CAD - was implemented in a PACS environment a structure that will provide storage and query contents extracted from diagnostic images. The contents extraction from images can be done by different processing methods that generate different parameters for storage and retrieval. The project was developed in partnership with a provider of solutions for PACS and the Applied Computing Laboratory of the Federal University of Santa Maria. / Uma das principais formas de diagnóstico utilizadas atualmente corresponde aos exames realizados por meio da análise de imagens diagnósticas. Devido à demanda crescente por esse tipo de exame e ao processo manual e repetitivo dos métodos utilizados pelos médicos radiologistas, começam a surgir novos meios para auxiliar os procedimentos. Uma ferramenta que pode ajudar o médico na formulação de diagnósticos é a busca de casos semelhantes àquele que está sendo realizado, tendo como função principal conferir maior segurança ao radiologista em seus apontamentos. Para tanto, foi desenvolvida uma arquitetura modular para recuperação de imagens diagnósticas baseada em conteúdo como uma ferramenta de auxílio a diagnósticos. Através do padrão DICOM SR, utilizado para armazenar achados radiológicos e mensurações - comumente provenientes de CAD - implementou-se, em um ambiente PACS, uma estrutura capaz de permitir o armazenamento e consulta de características extraídas das imagens diagnósticas. A extração de características das imagens pode ocorrer através de diferentes métodos de processamento que, por sua vez, geram diferentes parâmetros para armazenamento e consulta. O projeto foi desenvolvido em conjunto com uma empresa fornecedora de soluções de PACS e com o Laboratório de Computação Aplicada da Universidade Federal de Santa Maria.
48

Le droit de la famille : étude comparative des droits chinois et français / Family law : comparative study of the chinese and french laws

Qin, Yueren 25 June 2014 (has links)
La famille constitue la cellule d’une société, elle évolue selon plusieurs facteurs. Cette physionomie complexe de la famille conduit directement la loi sur ce sujet à devenir importante et changeant tant en Chine qu’en France. Nous avons réalisé une étude comparative pour analyser les régimes du droit de la famille dans ces deux pays. Parmi de multiples questions au sein du droit de la famille, nous examinons deux points essentiels pour approfondir et comparer : la vie de couple et la filiation. S’agissant de la vie de couple, nous nous interrogeons tant sur la formation des différentes modalités de l’union que sur leur dissolution. Nous nous apercevons que les diverses dispositions sur chaque union ont amené un régime plus complet en France qu’en Chine. Quant à la filiation, nous distinguons notamment la filiation liée par le sang de la filiation adoptive. L’ignorance du mode d’établissement de la filiation devient une grande lacune au sein du droit chinois. Par ailleurs, comment adopter un enfant ? Quelles sont les conditions à respecter et les procédures à achever ? Quels sont les effets issus de l’adoption ? Telles sont des questions à résoudre et à comparer dans cette thèse. À part certains points principaux sur le droit de la famille, nous nous posons des questions sur des problématiques provoquées en vue de connaître l’aptitude des législateurs dans les deux pays comme la maternité pour autrui, les mariages fictifs, etc. Enfin, nous tenterons d’expliquer pourquoi les régimes juridiques diffèrent en France et en Chine concernant les questions traitées dans cette thèse. / The concept of “Family” as an integral unit of the society has evolved over the years due to several reasons. This changing and complex face of “family” has had many implications on the laws both in China and in France. Hence, we conduct a comparative study to analyze the system of family laws in both these countries. The various questions we address in order to deepen our understanding of family laws can be broadly classified into: the couple and the filiation. As for the couple, we address many questions related not only to the formation of the various modalities of the union but also about their dissolution. We find that the diverse articles on each union brought a system which is more complete in France than in China. With respect to filiation, we distinguish in particular between the filiation bound by blood and that bound by adoption. The ignorance of the mode of establishment of the filiation results in a big gap in the Chinese law. Besides, the basic question of how to adopt a child, the conditions to be respected and the procedures to be finished, the effects stemming from the adoption are also the questions we explore, compare and attempt to solve in this thesis. Besides the several principal points on the family law, we also try to compare and understand the different views/perspectives of these two countries by looking into some other related issues such as the maternity for others, the fictive marriages, etc., as well as how the two countries deal with such matters. Finally, we try to explain why the legal system differs in France and in China and discuss the directions for future research.
49

台灣醫學影像業競爭力之研究-以PACS為例

王淑齡, Wang Shu-ling Unknown Date (has links)
傳統上利用X射線使底片曝光而顯影的醫學影像,不僅造成X光片的儲存、調閱與管理上的問題,同時洗片的週邊設備亦不符環保標準。隨著數位化時代的來臨,透過醫學影像儲傳系統(PACS)的建置,可以節省X光片和耗材成本、加速住院流程、提高整體醫療效率、增進影像判讀品質、解決X光片檔案室空間不斷增加問題等,醫療院所建置PACS將是必然趨勢,同時也彰顯出PACS之未來發展潛力。 然而,由PACS發展歷程及相關研究文獻來看,截至目前為止大多著重技術面之探討,針對整體產業之研究甚為缺乏。另一方面,以目前醫療產業發展的情形來看,全球性知名企業多藉由併購方式擴張市場,並且在台灣的PACS市場佔有一席之地。因此,本研究除了對我國目前PACS發展現況及趨勢作進一步的分析外,並探討台灣醫學影像業之發展潛力,希望藉由個案公司的訪談,分析本土企業成功的經營模式,以瞭解台灣未來在PACS市場是否具有發展空間,並提出產業未來發展方向建議。最後也希望透過分析本土企業的經驗,提供政府或相關單位參考,以利其制訂有利於創造良好產業環境之政策,培養我國醫療產業之發展。
50

Infection à coxsackievirus B4, inflammation et persistance / Coxsackievirus B4 infection, inflammation and persistence

Alidjinou, Enagnon Kazali 15 November 2016 (has links)
Les coxsackievirus du groupe B (CVB) sont des petits virus à ARN appartenant à au genre Enterovirus et à la famille des Picornaviridae. Chez, l’homme, les CVB sont responsables de nombreuses infections aiguës bénignes ou sévères. Ils sont également incriminés dans le développement de maladies chroniques telles que le diabète de type 1 (DT1). En effet, plusieurs données épidémio-cliniques sont en faveur d’un lien entre les entérovirus et notamment les CVB et le DT1. Deux mécanismes majeurs ont été proposés pour expliquer cette pathogenèse entérovirale du DT1. Il s’agit de l’activation « en passant » d’un environnement inflammatoire et la persistance virale qui concourent à l’initiation du processus auto-immun. Les études présentées dans cette thèse visent à comprendre les caractéristiques et conséquences de l’infection à CVB qui pourraient expliquer l’implication de ces mécanismes. Les résultats obtenus suggèrent que CVB4 (utilisé comme modèle des CVB) est un virus inflammatoire. In vitro, il induit la production de grandes quantités d’IFNα par les cellules mononuclées du sang (CMN). Néanmoins cette induction d’IFNα n’est possible qu’en cas de facilitation de l’infection par des anticorps non neutralisants, qui se traduit par une entrée importante du virus dans les cellules. Dans nos travaux, l’IFNα a été détecté dans le plasma de sujets diabétiques, et fréquemment associé à la présence d’ARN entéroviral. De même, parmi les CMN, les monocytes ont été identifiés comme les principales cellules cibles du virus. En dehors de l’IFNα, nous avons montré que CVB4 peut induire la synthèse de plusieurs autres cytokines pro-inflammatoires notamment l’IL-6 et le TNFα. De façon intéressante, l’infection des cellules n’est pas indispensable car cette induction est possible par des particules non infectieuses. Cette production de cytokines pro-inflammatoires par les CMN peut également être amplifiée par la facilitation de l’infection en présence de particules infectieuses de CVB4. Nous avons montré que les macrophages, cellules effectrices importantes de l’immunité innée au niveau tissulaire, peuvent produire en présence de CVB4 de l’IFNα et d’autres cytokines pro-inflammatoires. Les macrophages dérivés de CMN en présence de M-CSF (mais pas de GM-CSF) sont infectables par CVB4 et le virus peut persister dans ces cellules. CVB4 peut également établir une infection chronique productive de type « état porteur » dans des cellules canalaires pancréatiques. Les cellules chroniquement infectées peuvent être guéries grâce à un traitement par de la fluoxétine. Cette molécule utilisée dans le traitement de troubles psychiatriques, présente in vitro une activité antivirale vis-à-vis de certains entérovirus, et permet d’éliminer complètement en quelques semaines le virus des cellules chroniquement infectées par CVB4. Des modifications cellulaires ont été observées au niveau des cellules chroniquement infectées notamment une diminution de l’expression de PDX-1, une résistance à la lyse au cours d’une réinfection par CVB4, ainsi qu’une diminution très importante de l’expression du récepteur CAR. Ces modifications cellulaires acquises au cours de l’infection chronique pouvaient persister après l’élimination du virus. Les cellules chroniquement infectées présentent également un profil de microARNs très différent de celui des cellules non infectées. Une évolution du virus a été également observée avec des changements phénotypiques et génotypiques. L’ensemble de nos observations montre que les caractéristiques de l’infection à CVB4 sont compatibles avec les mécanismes évoqués dans la pathogenèse entérovirale du DT1 et renforcent l’hypothèse de l’implication des CVB dans cette maladie. / Group B coxsackieviruses (CVB) are small RNA viruses belonging to Enterovirus genus and to the Picornaviridae family. In humans, CVB can cause numerous mild and severe acute infections. They are also thought to be involved in the development of chronic diseases such as type 1 diabetes (T1D). Several epidemiological and clinical data support a link between enteroviruses, especially CVB and T1D. Two main mechanisms have been described to explain this enteroviral pathogenesis of T1D including a “bystander activation” of an inflammatory environment and viral persistence. These mechanisms contribute to initiation of the autoimmune process. Our studies aimed to understand the features and outcomes of CVB infection that could explain their involvement in these mechanisms. The results suggest that CVB4 (used as CVB model) is an inflammatory virus. CVB4 induces in vitro the production by peripheral blood mononuclear cells (PBMCs) of high amounts of IFNα. However this induction is only possible when CVB4 infection is enhanced by non-neutralizing antibodies, resulting in increased viral entry in cells. We also reported detection of IFNα in plasma of T1D patients, commonly associated with enteroviral RNA. In addition, monocytes have been identified as major targets of enteroviruses among PBMCs. Besides IFNα, CVB4 can induce the synthesis of other proinflammatory cytokines, mainly IL-6 and TNFα. Interestingly, infection is not needed, since inactivated viral particles can induce these proinflammatory cytokines. In addition, the enhancing of CVB4 infection in PBMCs results in increased production of these cytokines. We have shown that macrophages that are known as major innate immunity effectors can produce IFNα and other proinflammatory cytokines upon infection with CVB4. Macrophages derived from PBMCs in presence of M-CSF (but not GM-CSF) can be infected by CVB4, and the virus can persist in these cells. CVB4 can also establish a productive, carrier-sate persistent infection in pancreatic ductal-like cells. The virus can be completely cleared from chronically-infected cells using fluoxetine. This molecule already used in the treatment of depression and other mental disorders, has displayed antiviral activity against many enteroviruses, and can completely clear CVB4 from chronically-infected cells within few weeks. Cellular changes have been observed during chronic infection including a reduced expression of PDX-1, a resistant profile to lysis upon superinfection with CVB4, and an important decrease of CAR expression. These changes can linger even after the clearance of CVB4. In addition the miRNA profile in chronically-infected ductal-like cells was clearly different from that of mock-infected cells. Some phenotypic and genotypic changes were also observed in the virus derived from chronic infection. Altogether, these findings show the features of CVB4 infection are compatible with mechanisms reported in the enteroviral pathogenesis of T1D, and support the hypothesis of involvement of CVB in this disease.

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