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Des fantômes dans la voix : une hypothèse neuropsychanalytique sur la structure de l’inconscient / Phantoms in the voice : a neuropsychoanalytic hypothesis on the structure of the unconsciousBazan, Ariane 30 June 2009 (has links)
Ce travail dans le domaine de la « neuropsychanalyse » propose une spéculation théorique sur la structure physiologique de l’inconscient psychanalytique en recoupant les observations expérimentales et cliniques des deux cadres. L’écoute clinique indique une insistance de phonèmes récurrents dans ce qui fait conflit, appelés « phonèmes fantômes ». En effet, tel un membre fantôme, le signifiant refoulé est investi d’une intention mais son articulation est bloquée. Or, du fait de la structure ambiguë du langage, un même mouvement d’articulation peut radicalement changer de signification. C’est ce mécanisme qui donne lieu au retour du refoulé dans le signifiant et permet la survie de fantômes phonémiques qui tisseraient la structure linguistique de l’inconscient. Cette question du signifiant est présentée en écho à une question plus fondamentale, celle de l’émergence du psychique en réponse à la contrainte de l’organisme de faire la distinction entre intérieur et extérieur. Pour cette distinction, il faut supposer l’existence d’un système d’inhibition ciblé puisqu’il doit faire ressortir précisément ce qui dans la façon d’appréhender le monde extérieur n’a pas été anticipé. Cette précision est offerte par le modèle sensorimoteur des copies d’efférence, qui présentifie le mouvement avant qu’il ne se fasse et montre comment l’inhibition est condition de la représentation, constitutif du psychique. Pour l’humain la nécessité de la distinction intérieur-extérieur est impérieuse du fait précisément du langage qui rend complexe l’identification du lieu d’où ça parle. Elle mène au mouvement de refoulement, qui par inhibition fait apparaitre les fantômes phonèmiques comme les représentations en négatif des fragments de paroles refoulés. Cette réflexion théorique est précédée d’une mise en contexte élaborée dans l’histoire et l’épistémologique parfois controversée de la neuropsychanalyse et revendique pour sa méthodologie une approche transcendantale. / This study in the domain of « neuropsychoanalysis » proposes a theoretical speculation on the physiological structure of the psychoanalytic unconscious by cross-checking the experimental and clinical observations from both domains. Clinical listening indicates the insistence of recurring phonemes when it comes to conflictual topics, called “phonemic phantoms”. Indeed, as is the case in a phantom limb, the repressed signifier is invested by an intention while its articulation is blocked. However, due to the ambiguous structure of language, a same articulation movement can radically change signification. It is this mechanism that causes the return of the repressed in the signifier and allows for the survival of phonemic phantoms which are thought to weave the linguistic structure of the unconscious. The question of the signifier is presented as an instantiation of a more fundamental question, the emergence of the psychic realm in response to the constraint of the organism to distinguish interior from exterior. For this distinction, the existence of an accurate system of inhibition must be postulated since it has to be able to delineate precisely what in the way of apprehending the world was not anticipated by the organism. This precision is allowed by the sensorimotor model of efference copies, which presentifies the movement before its realisation and shows how inhibition is a condition for representation. For humans, the necessity of the interior-exterior distinction is imperious due to language which renders complex the identification of the locus from where speech is initiated (from where “id” speaks). This necessity leads to the movement of repression, which by inhibition induces phonemic phantoms in the form of negative representations of repressed speech. This work is preceded by an introduction which contextualises the theoretical reflexion in the sometimes controversial history and epistemology of neuropsychoanalysis and which claims a transcendental approach for its methodology.
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Cavitation-enhanced delivery of therapeutics to solid tumorsRifai, Bassel January 2011 (has links)
Poor drug penetration through tumor tissue has emerged as a fundamental obstacle to cancer therapy. The solid tumor microenvironment presents several physiological abnormalities which reduce the uptake of intravenously administered therapeutics, including leaky, irregularly spaced blood vessels, and a pressure gradient which resists transport of therapeutics from the bloodstream into the tumor. Because of these factors, a systemically administered anti-cancer agent is unlikely to reach 100% of cancer cells at therapeutic dosages, which is the efficacy required for curative treatment. The goal of this project is to use high-intensity focused ultrasound (HIFU) to enhance drug delivery via phenomena associated with acoustic cavitation. ‘Cavitation’ is the formation, oscillation, and collapse of bubbles in a sound field, and can be broadly divided into two types: ‘inertial’ and ‘stable’. Inertial cavitation involves violent bubble collapse and is associated with phenomena such as heating, fluid jetting, and broadband noise emission. Stable cavitation occurs at lower pressure amplitudes, and can generate liquid microstreaming in the bubble vicinity. It is the combination of fluid jetting and microstreaming which it is attempted to explore, control, and apply to the drug delivery problem in solid tumors. First, the potential for cavitation to enhance the convective transport of a model therapeutic into obstructed vasculature in a cell-free in vitro tumor model is evaluated. Transport is quantified using post-treatment image analysis of the distribution of a dye-labeled macromolecule, while cavitation activity is quantified by analyzing passively recorded acoustic emissions. The introduction of exogenous cavitation nuclei into the acoustic field is found to dramatically enhance both cavitation activity and convective transport. The strong correlation between inertial cavitation activity and drug delivery in this study suggested both a mechanism of action and the clinical potential for non-invasive treatment monitoring. Next, a flexible and efficient method to simulate numerically the microstreaming fields instigated by cavitating microbubbles is developed. The technique is applied to the problem of quantifying convective transport of a scalar quantity in the vicinity of acoustically cavitating microbubbles of various initial radii subject to a range of sonication parameters, yielding insight regarding treatment parameter choice. Finally, in vitro and in vivo models are used to explore the effect of HIFU on delivery and expression of a biologically active adenovirus. The role of cavitation in improving the distribution of adenovirus in porous media is established, as well as the critical role of certain sonication parameters in sustaining cavitation activity in vivo. It is shown that following intratumoral or intravenous co-injection of ultrasound contrast agents and adenovirus, both the distribution and expression of viral transgenes are enhanced in the presence of inertial cavitation. This ultrasound-based drug delivery system has the potential to be applied in conjunction with a broad range of macromolecular therapeutics to augment their bioavailability for cancer treatment. In order to reach this objective, further developmental work is recommended, directed towards improving therapeutic transducer design, using transducer arrays for treatment monitoring and mapping, and continuing the development of functionalized monodisperse cavitation nuclei.
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Addressing an old issue from a new methodological perspective : a proposition on how to deal with bias due to multilevel measurement error in the estimation of the effects of school compositionTelevantou, Ioulia January 2014 (has links)
With educational effectiveness studies, school-level aggregates of students' characteristics (e.g. achievement) are often used to assess the impact of school composition on students' outcomes – school compositional effects. Empirical findings on the magnitude and direction of school compositional effects have not been consistent. Relevant methodological studies raise the issue of under-specification at level 1 in compositional models - evident when the student-level indicator on which the aggregation is based is mis-measured. This phenomenon has been shown to bias compositional effect estimates, leading to misleading effects of the aggregated variables – phantom compositional effects. My thesis, consisted of three separate studies, presents an advanced methodological framework that can be used to investigate the effect of school composition net of measurement error bias. In Study 1, I quantify the impact of failing to account for measurement error on school compositional effects as used in value added models of educational effectiveness to explain relative school effects. Building on previous studies, multilevel structural equation models are incorporated to control for measurement error and/or sampling error. Study 1a, a large sample of English primary students in years one and four (9,059 students from 593 schools) reveals a small, significant and negative compositional effect on students' subsequent mathematics achievement that becomes more negative after controlling for measurement error. Study 1b, a large study of Cyprus primary students in year four (1694 students in 59 schools) shows a small, positive but statistically significant effect that becomes non-significant after controlling for measurement error. Further analyses with the English data (Study 2), demonstrates a negative compositional effect of school average mathematics achievement on subsequent mathematics self-concept – a Big Fish Little Pond Effect (BFLPE). Adjustments for measurement and sampling error result in more negative BFLPEs. The originality of Study 2 lies in verifying BFLPEs for students as young as five to eight/nine years old. Bridging the findings related to students' mathematics self-concept (Study 2) and the findings on students’ mathematics achievements (Study 1a), I demonstrate that the prevalence of BFLPEs with the English data partly explains the negative compositional effect of school average mathematics achievement on students' subsequent mathematics achievement. Lastly, in Study 3 I consider an alternative approach to school accountability to conventional value added models, namely the Regression Discontinuity approach. Specifically, I use the English TIMSS 1995 primary (years four and five) and secondary (years eight and nine) data to investigate the effect of one extra year of schooling on students' mathematics achievement and the variability across schools in their absolute effects. The extent to which school composition, as given by school average achievement, correlates with schools' added-year effects is addressed. Importantly the robustness of the RD estimates to measurement error bias is demonstrated. My findings have important methodological, substantive and theoretical implications for on-going debates on the school compositional effects on students' outcomes, because nearly all previous research has been based on traditional approaches to multilevel models, which are positively biased due to the failure to control for measurement error.
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Planification de traitements de curiethérapie du sein à l’aide de l’imagerie par résonance magnétiqueTruchon, Dany 12 1900 (has links)
Ce mémoire présente l’étude de la faisabilité de la planification de traitements pour
la curiethérapie interstitielle du sein en utilisant l’imagerie par résonance magnétique
(IRM) seule au lieu de l’imagerie par tomodensitométrie (CT). L'imagerie CT étant la référence, la mesure des différences observables sur la distribution de doses provenant des deux types d’imagerie a été effectuée. Des fantômes de seins ont été fabriqués et utilisés, ainsi que l’imagerie de patients. La taille des fantômes
en fonction du positionnement dans l’appareil d’IRM et la longueur reconstruite des cathéters ont été analysées. Les différences dans les distributions de doses de fantômes et de patients ont été calculées en s’assurant que la reconstruction des cathéters provenant des images CT et IRM est la seule variable. La différence dans les critères de doses à respecter est plus grande lorsque la taille du fantôme et/ou un déplacement latéral dans l’IRM sont plus grands. La longueur reconstruite des cathéters est comparable entre les deux techniques d’imagerie. Pour le petit fantôme des différences <2% ont été observées pour tous les critères de dose. Pour le grand fantôme et pour les patients, une valeur maximale de 5% est observée pour les critères sur la cible, mais peut atteindre 19% pour le critère Externe V150%/V100% pour le grand fantôme et 33% pour les patients. Par contre, le seuil clinique de ce critére est toujours respecté. Ceci nous indique que pour la plupart des patients, la zone à traiter serait bien couverte en utilisant les images IRM uniquement pour planifier. / This dissertation presents the study of the feasibility of planning for interstitial breast
brachytherapy treatments using only magnetic resonance imaging (MRI) instead of computed tomography (CT) imaging. CT imaging being the reference, the measurement of observable differences on dose distributions from the two types of imaging has been done. Breast phantoms has been fabricated and used, as imaging of patients. Size of the phantoms according to the positioning inside the MRI device and catheters reconstructed length has been analysed. Differences in dose distributions of phantoms and patients have been calculated by ensuring that catheters reconstruction from CT and MRI images is the only variable. The difference in respecting the dose’s criteria is bigger when the size and/or the lateral shift into the MRI are bigger. The catheters’ reconstructed length is similar between the two imaging techniques. For the small phantom, differences <2% has been observed for all dose criteria. For the large phantom and for patients, a maximum value of 5% is observed for targets criteria, but can reach 19% for External V150/V100 criterion for the large phantom and 33% for patients. However, clinical threshold for this criterion is still respected. This tells us that for most patients, the treatment region would be covered by using MRI images only for planning.
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Optimisation de l’angiomammographie et de l’angiotomosynthèse double-énergie / Optimization of contrast enhanced digital mammography and contrast enhanced digital breast tomosynthesisDromain, Clarisse 07 January 2015 (has links)
Objectifs : L’objectif a été de d’optimiser les protocoles d’acquisition des examens d’angiomammographie double-énergie, d’étudier la faisabilité de l’angiotomosynthèse pour la détection et la caractérisation des tumeurs mammaires, et d’étudier la faisabilité des biopsies stéréotaxiques sous guidage de l’angiomammographie. Méthodes : Une étude d’optimisation des paramètres d’acquisition de l’angiomammographie a été réalisée dans 4 situations cliniques pour lesquelles la qualité diagnostique requise des images de basse énergie et la dose totale délivrée à la patiente ne sont pas identiques. L’optimisation des paramètres d'exposition (anode/filtre, kVp, mAs) des images de basse énergie (BE) et haute énergie (HE) a été réalisée à partir d’une modélisation théorique de la chaîne d’acquisition. Une validation a été effectuée par mesures expérimentales sur des images de fantôme d’inserts d’iode. Nous avons ensuite étudié la technique d’angiotomosynthèse mammaire basée sur une approche double-énergie. Un nouveau fantôme anthropomorphique numérique du sein et de ses lésions, basé sur l’utilisation de primitives géométriques complexes et d’une technique de maillage surfacique, a été amélioré et utilisé pour évaluer les performances de l’angiomammographie optimisée, puis de l’angiotomosynthèse en comparaison à l’angiomammographie. Enfin, nous avons proposé un scénario pour la réalisation d’un examen de stéréotaxie avec injection d’un agent de contraste iodé et étudié la faisabilité de recombinaison d’image de haute et de basse énergie acquises à des temps différents de l’injection.Résultats et conclusion : Les optima des paramètres d’exposition trouvés par simulation avec les valeurs de SDNRpixel et SDNR2pixel /Dosetotale qui en résultent, ont été confirmés expérimentalement. Les valeurs de SDNR par pixel dans les images recombinées sont augmentées pour toutes les indications cliniques en comparaison à celle obtenues avec SenoBright ® (produit commercial de référence). L'impact sur la qualité de l’image de BE, évalué par des expérimentations sur fantôme CDMAM, a montré que les paramètres optimisés fournissent une détection similaire ou acceptable par rapport à la mammographie standard, à l’exception de l'indication de dépistage lorsque l’on considère les objets de très petits diamètres.L’étude de lecture humaine d’images simulées d’un fantôme anthropomorphique du sein incluant le rehaussement glandulaire physiologique et différents modèle tumoraux n’a pas montré d’augmentation significative de sensibilité de détection des acquisition 3D d’angiotomosynthèse comparativement aux acquisitions 2D d’angiomammographie. Les deux paramètres qui influençaient le plus la sensibilité était la concentration en iode des tumeurs et la densité du sein. L’angiomammographie était par ailleurs significativement plus spécifique que l’angiotomosynthèse. Une perspective d’amélioration pour l’angiotomosynthèse pourrait donc être l’utilisation d’algorithmes de reconstruction 3D spécifiques de cette modalité qui minimiseraient le bruit de reconstruction. Le scénario proposé pour la réalisation de biopsies sous guidage de l’angiomammographie, a mis en évidence deux contraintes techniques que sont l’échauffement du tube à rayons X et le surcroit de dose dû à la répétition des paires d’acquisitions en haute et basse énergies. Une des solutions envisagées a été de limiter le nombre d’acquisitions de BE. Notre étude a montré que la recombinaison d’une image HE avec une image BE acquise antérieurement modifiait le SDNR des lésions simulées comparativement à une recombinaison appariée d’images BE et HE acquises au même temps de l’injection. Ces modifications dépendaient du temps du pic de rehaussement maximal et du washout de la lésion. / Objectives: The purpose was to optimize the exposure parameters of CESM examinations, to assess the feasibility of contrast-enhanced DBT (CE-DBT) for the detection and the characterization of breast tumors, and to assess CESM-guided stereotactic biopsies. Methods: At first, we optimized the CESM exposure parameters in four different clinical applications for which different levels of average glandular dose and different low energy image quality are required. The optimization of exposure parameters (anode/filter, kVp, mAs) for low energy (LE) and high energy (HE) images at different levels of average glandular dose and different ratios between LE and total doses has been conducted using a simulator of the x-ray mammographic image chain. An experimental validation was then performed through phantom experiments. Secondly, we assessed the potential of CE-DBT based on a dual-energy approach. A new mesh-based anthropomorphic breast phantom was improved and used to evaluate the performance of CESM and then to compare CESM and CE-DBT. Finally, we evaluated the technical feasibility of CESM-guided biopsy. After identifying some technical constraints, we assessed the performance of the recombination of LE and HE images acquired at different times after injection, using simulated images of a geometric phantom with uniform texture, and simulated images of an anthropomorphic textured phantom with and without motion artifacts.Results and conclusion : For the four different clinical indications, optima found by simulation, with resulting SDNRpixel and SDNR2pixel/Dosetotal, were confirmed through real acquisition of images on phantoms. Our results indicate that the SDNR per pixel in recombined CESM images increased in all of the four clinical indications compared to recombined images obtained using SenoBright ® (commercial product used as reference). This result suggests the possibility to detect more subtle contrast enhancements and to decrease the number of false negatives found in clinical CESM examinations. The impact of a new dose allocation between LE and HE exposures was also evaluated on LE image quality. Results from CDMAM phantom experiments indicate that optimized parameters provide similar or acceptable detection compared to standard mammography, except for screening indication when considering the very small diameter objects.The human observer study on anthropomorphic phantom images, taking into account tumor and breast parenchyma enhancement, revealed that detection and characterization sensitivity of iodine-enhanced lesions are not statistically different between 2D CESM and 3D CE-DBT. The most influencing parameters for the detectability and the lesion size assessment were the lesion iodine concentration and the breast density. CESM was significantly more specific than CE-DBT. One of the assumptions to explain this result is the presence of higher noise in CE-DBT than in CESM images. A future improvement for CE-DBT could therefore be the design of a specific reconstruction algorithm minimizing reconstructed noise.With respect to CESM-guided biopsy the proposed scenario pointed out two major constraints, one related to the thermal load of the x-ray tube, the second related to the increased dose due to the repetition of LE and HE images. One proposed solution was to limit the number of LE exposures, requiring the possibility to recombined LE and HE images acquired at different injection time points. Our study showed that the recombination of a HE image with a LE image acquired earlier leads to SDNR changes compared to paired recombination. These changes are function of the enhancement time to peak and the washout of the lesion, and had a limited impact on the lesion detectability.
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Integration magnetresonanztomographischer und computertomographischer Daten mit isotropen Voxeln in die Protonenbestrahlungsplanung bei okularen TumorenLemke, Arne-Jörn 12 November 2001 (has links)
Die Bestrahlungstherapie von Aderhautmelanomen mit der Protonentherapie stellt ein sehr präzises Behandlungsverfahren dar, welches hohe Ansprüche an die zugrundliegende Bildgebung stellt. Die Magnetresonanztomographie (MRT) und Computertomographie (CT) scheinen prinzipiell in der Lage, mit geeigneten Oberflächenspulen bzw. angepaßter Untersuchungstechnik diese Ansprüche zu erfüllen. Ziel der Arbeit ist die Bereitstellung und Überprüfung eines bildgebenden Systems, das einerseits die diagnostischen und differentialdiagnostischen Aufgaben für die Differenzierung und das Staging von Aderhautmelanomen erfüllt und andererseits als Grundlage der Bestrahlungsplanung dienen kann. Erstrebenswert ist dabei die Erstellung von Schnittbildern bestehend aus isotropen Voxeln, d.h. Voxeln mit identischer Kantenlänge, mit der Magnetresonanztomographie (MRT) und der Computertomographie (CT). Zur Differenzierung der unterschiedlichen Tumorentitäten wurden verschiedene Untersuchungen mit zum Teil großen Patientenkollektiven durchgeführt und histologisch und klinisch korreliert bzw. verifiziert. Dabei konnte das MR-morphologische Erscheinungsbild der relevanten Erkrankungen studiert werden. Die Genauigkeit der MR-gestützten Tumorvolumetrie wurde in vitro im Tierversuch und in vivo am Patientenauge überprüft. Zur Überprüfung der Genauigkeit der MR-Bildgebung mit isotropen Voxeln wurden unterschiedliche Spulen getestet und verschiedene Phantomuntersuchungen durchgeführt. Entsprechend wurde auch die CT evaluiert. Mit der digitalen Bildfusion wurden die MRT- und die CT-Daten in einen gemeinsamen Datensatz überführt, der sowohl zur Bestimmung der Genauigkeit beider Verfashren als auch als Basis zur Bestrahlungsplanung verwendet werden konnte. Mit einer optimierten Untersuchungstechnik konnten Schnittbilder auf der Basis von CT und MRT zur Verfügung gestellt werden, die eine präzise Planung der Protonenbestrahlung beim Aderhautmelanom ermöglichen. / The radiation therapy of uveal melanomas using proton therapy is a very precise therapy procedure, that makes high demands on the underlying imaging modalities. In general magnetic resonance imaging (MRI) and computed tomography (CT) have the potential to fulfill these criteria using suited surface coils and optimized imaging techniques, respectively. Purpose of the investigations was the preparation and evaluation of an imaging system, that allows diagnosis and differetial diagnosis of uveal melanomas including staging on the one hand. On the other hand it should be the base for high precision radiation therapy planning. The preparation of images with isotropic voxels, i.e. the edges of the voxels have identical size, is desirable with both magnetic resonance imaging (MRI) and computed tomography (CT). Several examinations on large patient groups were performed for the differentiation of different tumor entities and compared with clinical and histopathological outcome. The precision of the MR-based tumor volumetry was evaluated with animal studies in vitro and patient eyes in vivo. The MR-imaging with isotropic voxels was evaluated using several surface coils and phantom examinations. Comparable examinations were performed regarding CT. Digital image fusion of CT and MRI data sets was used to evaluate the precision of both modalities and for planning of radiation therapy. Using optimized examination techniques both CT and especially MRI are suitable for a precise proton therapy planning of uveal melanoma.
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[en] WHERE WOULD BE HILDA HILST?: CRITICAL READING OF CANTARES DO SEM NOME E DE PARTIDA / [pt] ONDE ANDARÁ HILDA HILST?: LEITURA CRÍTICA DE CANTARES DO SEM NOME E DE PARTIDAANA BEATRIZ FERREIRA BATISTA 03 June 2019 (has links)
[pt] Onde andará Hilda Hilst? Leitura crítica de Cantares do sem nome e de partida, discute a relação do adeus encenado nos poemas do seu último livro de poemas inéditos publicados com o efetivo gesto de anunciar a interrupção de mais de quarenta anos de publicações contínuas. Fundados e erguidos sob o signo da despedida, estes poemas demarcam a matriz da poesia ocidental, seu contexto histórico, como território para alianças e transgressões éticas e estéticas. Subvertendo a ausência que funda e mobiliza a criação de textos nas tradições em questão, a Lírica Trovadoresca e a Fábula Mística, Hilda Hilst constrói esta ausência. A partir da ausência construída pelos poemas de Cantares do sem nome e de partida, pelo anúncio do fim de novas publicações, um deslocamento de lugar enunciativo da autora deflagra na cena cultural um espaço paradoxal: fechado e aberto (fechado na medida em que define a obra como acabada, aberto na medida em que a autora pode se referir a sua atividade de escritora e à sua obra com a distância crítica do passado). Este novo espaço criado, propício à emergência de vozes políticas, ao mesmo tempo em que viabiliza a circulação deste texto e também dos outros textos de Hilda Hilst (até então pouco conhecidos pelo público leitor não especializado por conta do tipo de distribuição mercadológica que tiveram), também coloca em questão os critérios de seleção e distribuição do mercado editorial. / [en] Where is Hilda Hilst? Critical reading of Cantares do sem nome e de partida, discusses the relation of farewell staged in poems of her last book of inedited poems published with the effective gesture to announce the interruption of more than forty years of continuous publications. Founded and built under the sign of parting, these poems delineate the matrix of occidental poetry, its historical context, as a territory for alliances and for ethical and aesthetic transgressions. Subverting the absence that establishes and mobilizes the creation of texts in the traditions in question, the Troubadours lyric and the Mystics fable, Hilda Hilst constructs this absence. From the absence built by the poems of the Cantares do sem nome e de partida, and starting at the announcement of the end of new publications, a shift of the author s place of enunciation in the cultural scene triggers a paradoxical space: closed and opened (closed in the measure where she defines her work as finished, opened in the extent where the author can mention its activity of writer and its literary pursuits with in the critical distance of the past). This new space created, propitious to emergency of politics voices, at the same time it allows the circulation of this text and also from other texts by Hilda Hilst (until then barely unknown by non-specialist readers on account of the type of marketing distribution that they had), also it places in question the criteria of election and distribution of the publishing market.
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Strid i bebyggelse - Vilka faktorer möjliggör framgångRask, Lars January 2018 (has links)
Världen globaliseras och urbaniseras i en allt högre takt vilket innebär utmaningar för framtida försvarsmakter. Försvarsmakterna kommer mer frekvent att få lösa militära operationer genom strid i bebyggelse (SIB). Denna undersöknings ansats är att pröva Alice Hills teori om framgångsfaktorer som analyserats fram ur krigshistoriens militära operationer i kontexten SIB. Hills argumenterar för en mängd framgångsfaktorer. Denna undersökning prövar faktorerna utbildningsståndpunkt/stridserfarenhet, tillgång till infanteriförband, nyttjande av indirekt bekämpning och tredje parts inverkan på operationer. Dessa faktorer prövas i en jämförande fallstudie av operationerna i Fallujah 2004 Operation Vigilant Resolve (misslyckad operation) och Operation Phantom Fury (framgångsrik operation) vilka båda ingick i Operation Iraqi Freedom. De källor som har nyttjats för att genomföra teoriprövningen är Vincent L. Foulks, ”The Battle for Fallujah: Occupation, Resistance and Stalemate in the War in Iraq” och Bing Wests ”No True Glory: A Frontline Account of the Battle for Fallujah”. Resultatet av undersökningen stärker Hills teori om de fyra prövade framgångsfaktorerna. Fallstudien påvisar att ingående förband i Operation Vigilant Resolve (misslyckad operation) endast hade en grundlagd utbildningsståndpunkt i SIB samt att stora delar av förbanden saknade stridserfarenhet. Vidare påvisar undersökningen att det var låg numerär av infanteriförband och att mixen mellan infanteri och pansarförband medförde att infanteriförbanden inte kunde lösa uppgiften att skydda pansarförbanden i tillräcklig omfattning. I denna operation finns inget som bevisar att någon form att markgrupperad, indirekt bekämpning nyttjats. Tredje parts påverkan var stor givet förutsättningen att endast en mindre del av befolkning flytt staden Fallujah. Operation Phantom Fury påvisar det motsatta gentemot Operation Vigilant Resolve. Förbanden var bättre utbildade genom att de fått dra lärdom under genomförande under Operation Vigilant Resolve samt att de fått stridserfarenhet genom samma operation. Stor numerär av infanteri och en bättre mix av infanteri och pansarförband där infanteriet understöddes av pansarförbanden istället för tvärtom som var fallet vid Operation Vigilant Resolve. Operation nyttjade indirekt bekämpning i form av granatkastare och artilleri i stor omfattning. Den fjärde och sist prövande framgångsfaktorn, tredje parts inverkan på operationen påvisar att stora delar av staden Fallujah var utrymd vilket indirekt påverkar framförallt faktorn nyttjande av indirekt bekämpning. Sammanfattningsvis stärker denna teoriprövande fallstudie Hills förklaringskraft avseende de fyra utvalda framgångsfaktorerna. Detta ger en vetenskaplig grund att bygga framtidens förband kring där SIB kommer vara frekvent återkommande.
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Modificação das posturas dos simuladores antropomórficos voxel de referência Adult Male (AM) e Adult Female (AF) para cálculo de coeficientes de conversão de dose / Posture modification of the reference anthropomorphic voxel phantom Adult Male (AM) and Adult Female (AF) for dose conversion coefficients calculationGaleano, Diego Castanon 11 October 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Establish limits to the exposure of the population to various ionizing radiation sources is
crucial to prevent occupationally exposed individuals and the public, to their deleterious
effects. In computational ambit, it is necessary that different exposure scenarios are
simulated in order to obtain the dose coefficients (CCs), which relate physical dosimetric
quantities - as absorbed dose, Fluency or Kerma Air - with limiting quantities - as equivalent
and / or effective dose. Under certain exposure conditions, the individual's posture is not
always the same, and the scenario shall be described as realistic as possible. In this work, the
AM (Adult Male) and AF (Adult Female) anthropomorphic reference phantom of ICRP
publication n° 110 had their postures modified from supine posture (standing) to sitting
posture. The change of posture was performed through of a subroutine written in the Visual
Monte Carlo code (VMC) to rotate the thigh region of the phantom and position it between
the region of the leg and torso. The ScionImage software was used to reconstruct and smooth
the knee and hip contours in a sitting posture phantom, and for 3D visualization of phantom
was used VolView software. After this step the MCNPX radiation transport code was used
for the calculation of fluence-to-dose conversion coefficients (CCs) to six irradiation
geometries: AP, PA, LLAT, RLAT, ROT and ISO, recommended by ICRP. The results were
compared between the phantoms in standing and sitting postures, for both sexes, in order to
assess differences in scattering and absorption of radiation in different postures. The results
show significant differences of up to 100% in the equivalent dose conversion coefficients of
organs in the pelvic region, 79 % in organs with distribution in the whole body (such as skin,
muscle, lymph nodes, bone marrow and trabecular bone) and a difference of 27% to effective
dose conversion coefficients. Moreover in order to conduct a comparative study between
two types of simulators, was estimated CCs equivalent and effective dose of adult male
hybrid simulators, UFHADM, and female, UFHADF, in a sitting posture, and compared to
the AM and AF simulators, also in the sitting posture, where it was observed significant
difference in energies below 0.05 MeV. This study demonstrated the feasibility of using
anthropomorphic phantoms in the sitting posture to represent more realistic postures and can
be used in studies in medical and occupational dosimetry. This study demonstrated the
feasibility of using anthropomorphic simulators reference in the seated position to represent
more realistic positions can thus be used in studies in medical and occupational dosimetry
as well as the importance of developing as realistic simulators as possible to dose estimation
as faithful as possible in different irradiation scenarios. / Estabelecer limites à exposição da população a diversas fontes de radiação ionizante é de
fundamental importância para prevenir indivíduos, ocupacionalmente expostos e do público,
dos seus efeitos deletérios. Em âmbito computacional, é necessário que diferentes cenários
de exposição sejam simulados, visando à obtenção dos coeficientes de dose (CCs), que
associam grandezas dosimétricas físicas – como dose absorvida, fluência ou kerma no ar –
com grandezas limitantes – como equivalente e/ou dose efetiva. Em certas condições de
exposição a posição do indivíduo nem sempre é a mesma, e o cenário deve ser descrito da
forma mais realística possível. Neste trabalho, os simuladores antropomórficos de referência
da publicação nº 110 da ICRP, AM (Adult Male) e AF (Adult Female), tiveram suas posturas
modificadas da postura supinada (em pé) para a postura sentada. A mudança de postura foi
realizada por meio de uma subrotina escrita no software Visual Monte Carlo (VMC) para
rotacionar a região da coxa dos simuladores e posicioná-la entre a região da perna e do
tronco. O software ScionImage foi utilizado para reconstruir e suavizar os contornos no
joelho e quadril dos simuladores na postura sentada, e com ferramenta auxiliar para
visualização 3D dos simuladores foi utilizado o software VolView. Após essa etapa foi
utilizado o código de transporte de radiação MCNPX para o cálculo dos coeficientes de
conversão (CCs) de dose equivalente e efetiva por fluência de partículas, calculados para
seis geometrias de irradiação AP, PA, LLAT, RLAT, ROT e ISO, recomendadas pela ICRP.
Os resultados foram comparados entre os simuladores em pé e sentado, para ambos os
gêneros, com o objetivo de avaliar as diferenças de espalhamento e absorção da radiação
para as diferentes posturas. Os resultados dos CCs mostram diferenças significativas, de até
100 % para dose equivalente dos órgãos situados a região pélvica e 79 % em órgãos com
distribuição em todo o corpo como, por exemplo, pele, músculo, nódulos linfáticos medula
óssea e trabécula óssea, e uma diferença de 14 % para dose efetiva. Ademais, a fim de
realizar um estudo comparativo entre dois tipos de simuladores, foi estimado os CCs de dose
equivalente e efetiva dos simuladores híbridos adulto masculino, UFHADM, e feminino,
UFHADF, na postura sentada, e comparado com os simuladores AM e AF, também na
postura sentada, onde foi observado diferença significativa em energias abaixo de 0,05 MeV.
Este estudo demonstrou a viabilidade do uso dos simuladores antropomórficos de referência
na postura sentada para representar posturas mais realísticas podendo assim, ser utilizado em
estudos na dosimetria médica e ocupacional, bem como a importância de desenvolver
simuladores tão realista quanto possíveis para estimativa de dose tão fiéis quanto possíveis
em diversos cenários de irradiação.
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Methods for determination of the accuracy of surgical guidance devices:a study in the region of neurosurgical interestKoivukangas, T. (Tapani) 11 September 2012 (has links)
Abstract
Minimally invasive surgery (MIS) techniques have seen rapid growth as methods for improved operational procedures. The main technology of MIS is based on image guided surgery (IGS) devices, namely surgical navigators, surgical robotics and image scanners. With their widespread use in various fields of surgery, methods and tools that may be used routinely in the hospital setting for “real world” assessment of the accuracy of these devices are lacking.
In this thesis the concept of accuracy testing was developed to meet the needs of quality assurance of navigators and robots in a hospital environment. Thus, accuracy was defined as the difference between actual and measured distances from an origin, also including determination of directional accuracy within a specific volume. Two precision engineered accuracy assessment phantoms with assessment protocols were developed as advanced materials and methods for the community. The phantoms were designed to include a common region of surgical interest (ROSI) that was determined to roughly mimic the size of the human head. These tools and methods were utilized in accuracy assessment of two commercial navigators, both enabling the two most widely used tracking modalities, namely the optical tracking system (OTS) and the electromagnetic tracking system (EMTS). Also a study of the accuracy and repeatability of a prototype surgical interactive robot (SIRO) was done. Finally, the phantoms were utilized in spatial accuracy assessment of a commercial surgical 3D CT scanner, the O-Arm.
The experimental results indicate that the proposed definitions, tools and methods fulfill the requirements of quality assurance of IGS devices in the hospital setting. The OTS and EMTS tracking modalities were nearly identical in overall accuracy but had unique error trends. Also, the accuracy of the prototype robot SIRO was in the range recommended in the IGS community. Finally, the image quality of the O-Arm could be analyzed using the developed phantoms. Based on the accuracy assessment results, suggestions were made when setting up each IGS device for surgical procedures and for new applications in minimally invasive surgery. / Tiivistelmä
Mini-invasiivisen eli täsmäkirurgian tekniikoita ja teknologioita on alettu hyödyntää viime aikoina yhä enemmän. Tavoitteena on ollut parantaa kirurgisten operaatioiden tarkkuutta ja turvallisuutta. Täsmäkirurgiassa käytetyt teknologiat pohjautuvat kuvaohjattuihin kirurgisiin paikannuslaitteisiin. Kuvaohjattuihin laitteisiin kuuluvat navigaattorit, kirurgiset robotit ja kuvantalaitteet. Näiden laitteistojen kehittyminen on mahdollistanut tekniikoiden hyödyntämisen monialaisessa kirurgiassa. Paikannuslaitteistojen ja robottien yleistyminen on kuitenkin nostanut sairaaloissa esiin yleisen ongelman paikannustarkkuuden määrittämisessä käytännön olosuhteissa.
Tässä väitöskirjassa esitetään kirurgisten yksiköiden käyttöön menetelmä sekä kaksi uutta fantomia ja protokollaa käytössä olevien paikannuslaitteistojen tarkkuuden määrittämiseen. Fantomit suunniteltiin sisältämään ennalta määritetty kirurginen kohdealue, mikä rajattiin käsittämään ihmisen kallon tilavuus. Fantomeita ja protokollaa hyödynnettiin kahden kaupallisen paikannuslaitteen tarkkuuden määrityksessä. Navigaattorit käyttivät optiseen ja elektromagneettiseen paikannukseen perustuvaa tekniikkaa. Lisäksi työssä kehitetyillä menetelmillä tutkittiin prototyyppivaiheessa olevan kirurgisen robotin paikannus- ja toistotarkkuutta sekä tietokonetomografialaitteen O-kaaren kuvan tarkkuuden määritystä.
Kokeellisten tulosten perusteella työssä kehitetyt fantomit ja protokollat ovat luotettavia ja tarkkoja menetelmiä kirurgisten paikannuslaitteistojen tarkkuuden määrittämiseen sairaalaoloissa. Kirurgisten navigaattoreiden tarkkuuden määritystulokset osoittivat optisen ja elektromagneettisen paikannustekniikan olevan lähes yhtä tarkkoja. Prototyyppirobotin tarkkuus oli tulosten perusteella kirjallisuudessa esitettyjen suosituksien mukainen. Lisäksi O-kaaren kuvanlaatua voitiin tutkia kehitetyillä fantomeilla. Tarkkuudenmääritystulosten perusteella työssä ehdotetaan menetelmiä laitteistojen optimaalisesta käytöstä leikkaussalissa sekä laajennetaan niiden käyttömahdollisuuksia. Tuloksia voidaan hyödyntää myös paikannuslaitteistojen kehittämistyössä.
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