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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.
51

Statistical modeling and processing of high frequency ultrasound images : application to dermatologic oncology / Modélisation et traitement statistiques d’images d’ultrasons de haute fréquence. Application à l’oncologie dermatologique.

Pereyra, Marcelo 04 July 2012 (has links)
Cette thèse étudie le traitement statistique des images d’ultrasons de haute fréquence, avec application à l’exploration in-vivo de la peau humaine et l’évaluation non invasive de lésions. Des méthodes Bayésiennes sont considérées pour la segmentation d’images échographiques de la peau. On y établit que les ultrasons rétrodiffusés par la peau convergent vers un processus aléatoire complexe de type Levy-Flight, avec des statistiques non Gaussiennes alpha-stables. L’enveloppe du signal suit une distribution Rayleigh généralisée à queue lourde. A partir de ces résultats, il est proposé de modéliser l’image ultrason de multiples tissus comme un mélange spatialement cohérent de lois Rayleigh à queues lourdes. La cohérence spatiale inhérente aux tissus biologiques est modélisée par un champ aléatoire de Potts-Markov pour représenter la dépendance locale entre les composantes du mélange. Un algorithme Bayésien original combiné à une méthode Monte Carlo par chaine de Markov (MCMC) est proposé pour conjointement estimer les paramètres du modèle et classifier chaque voxel dans un tissu. L’approche proposée est appliquée avec succès à la segmentation de tumeurs de la peau in-vivo dans des images d’ultrasons de haute fréquence en 2D et 3D. Cette méthode est ensuite étendue en incluant l’estimation du paramètre B de régularisation du champ de Potts dans la chaine MCMC. Les méthodes MCMC classiques ne sont pas directement applicables à ce problème car la vraisemblance du champ de Potts ne peut pas être évaluée. Ce problème difficile est traité en adoptant un algorithme Metropolis-Hastings “sans vraisemblance” fondé sur la statistique suffisante du Potts. La méthode de segmentation non supervisée, ainsi développée, est appliquée avec succès à des images échographiques 3D. Finalement, le problème du calcul de la borne de Cramer-Rao (CRB) du paramètre B est étudié. Cette borne dépend des dérivées de la constante de normalisation du modèle de Potts, dont le calcul est infaisable. Ce problème est résolu en proposant un algorithme Monte Carlo original, qui est appliqué avec succès au calcul de la borne CRB des modèles d’Ising et de Potts. / This thesis studies statistical image processing of high frequency ultrasound imaging, with application to in-vivo exploration of human skin and noninvasive lesion assessment. More precisely, Bayesian methods are considered in order to perform tissue segmentation in ultrasound images of skin. It is established that ultrasound signals backscattered from skin tissues converge to a complex Levy Flight random process with non-Gaussian _-stable statistics. The envelope signal follows a generalized (heavy-tailed) Rayleigh distribution. Based on these results, it is proposed to model the distribution of multiple-tissue ultrasound images as a spatially coherent finite mixture of heavy-tailed Rayleigh distributions. Spatial coherence inherent to biological tissues is modeled by a Potts Markov random field. An original Bayesian algorithm combined with a Markov chain Monte Carlo method is then proposed to jointly estimate the mixture parameters and a label-vector associating each voxel to a tissue. The proposed method is successfully applied to the segmentation of in-vivo skin tumors in high frequency 2D and 3D ultrasound images. This method is subsequently extended by including the estimation of the Potts regularization parameter B within the Markov chain Monte Carlo (MCMC) algorithm. Standard MCMC methods cannot be applied to this problem because the likelihood of B is intractable. This difficulty is addressed by using a likelihood-free Metropolis-Hastings algorithm based on the sufficient statistic of the Potts model. The resulting unsupervised segmentation method is successfully applied to tridimensional ultrasound images. Finally, the problem of computing the Cramer-Rao bound (CRB) of B is studied. The CRB depends on the derivatives of the intractable normalizing constant of the Potts model. This is resolved by proposing an original Monte Carlo algorithm, which is successfully applied to compute the CRB of the Ising and Potts models.
52

Peace Negotiations of Sri Lankan Conflict in 2000-2006 : The Ceasefire Agreement Facilitated by Norway is at Stake

Paramanathan, Mathivathana January 2007 (has links)
The objective of the thesis is to study the Sri Lankan negotiation process during 2000-2006 sponsored by the Norwegian facilitation and further to analyse the major constraints hin-dering a final solution. The stated purpose is analysed by studying both primary and secondary materials such as official documents, research and newspaper articles. One of the major findings of the thesis is that the Norwegian facilitation has not been very effective mainly due to both domestic and international political developments in recent years. In the case of domestic politics, the Sri Lankan political arena has a tradition of political crisis which is mainly a result of the two major Sinhalese parties fighting for power. These parties have been blocking any sus-tainable solution for Tamil demands while focusing on their political power. Furthermore, international attitudes towards the warring parties are found to have had a huge impact on the Sri Lankan peace process during the studied period. Since one of the major constraints in the negotiation process appears to be that the Government of Sri Lanka seems to have adopted the international “realpolitik” on its domestic issue in the name of the war on terror. This political strategy may further inflate the already existing na-tionalism among the Sinhalese majority and the Tamil minority and thus may intensify the conflict.
53

Optimisation des techniques avancées en IRM cérébrale dans la détection des lésions développementales épileptogènes / Optimization of advanced MRI tools in the detection and characterization of epileptogenic developmental lesions

Mellerio, Charles 29 September 2014 (has links)
Les dysplasies corticales focales de type 2 (DCF2) sont une cause fréquente d’épilepsie partielle pharmacorésistante pouvant bénéficier d’un traitement chirurgical. Leur détection en IRM est un facteur indépendant de bon pronostic. Leur diagnostic reste difficile avec jusqu’à 40% d’IRM négatives. Le travail de cette thèse a pour principal objectif d’améliorer la détection des DCF2 à partir des séquences conventionnelles, d’évaluer la pertinence d’une augmentation de champ magnétique, et de valider de nouveaux outils de détection, en particulier par l’identification d’anomalies des sillons associées aux DCF2 de manière automatique puis visuelles. Cette étude a été réalisée à partir d’une des plus importante cohorte de patients (>80 patients) porteurs de DCF2 prouvée histologiquement. L’évaluation de la fréquence de chacun des signes en IRM nous a permis de démontrer que, bien qu’aucune anomalie ne soit visible dans 41% des cas, les différents signes chez les patients avec une IRM positive n’étaient jamais isolés et que la combinaison des 3 signes les plus évocateurs de DCF2 (épaississement cortical, flou de l'interface blanc-gris et « transmantle sign »), était retrouvée chez 27 patients (64%) suggérant que l’IRM puisse être un examen très caractéristique. En augmentant le champ magnétique de 1,5 à 3T en IRM le taux de détection n’est que peu modifié mais la caractérisation des DCF2 est améliorée en raison d’une meilleure visualisation du « transmantle sign », considéré comme une signature en IRM des DCF2. L’analyse automatisée des sillons basés sur le calcul d’un nouveau paramètre appelé « énergie sulcale » permet d’identifier des motifs sulcaux anormaux chez les patients porteurs de DCF2 dans la région centrale en comparaison aux sujets sains. Ce résultat souligne l'importance d’une étude des sillons et pourrait fournir un critère supplémentaire pour détecter et localiser la lésion chez des patients à IRM négative. Enfin, l’analyse visuelle des sillons par un reformatage 3D du cortex nous a permis de décrire un nouveau marqueur des DCF2 de la région centrale : un motif sulcal dénommé le "Power Button Sign". Compte tenu de son excellente reproductibilité et de sa spécificité, il pourrait être utilisé comme un nouveau critère diagnostic majeur de DCF2 de la région centrale. L’ensemble de ces résultat participe à la meilleure compréhension des phénomènes développementaux impliqués dans la physiopathologie des DCF2 et offre de nombreuses perspectives pour l’amélioration de leur détection en imagerie. / Focal cortical dysplasia type 2 (FCD2) is a common cause of intractable partial epilepsy surgically treatable. Their detection by MRI is an independent factor of good prognosis. The MR imaging diagnosis remains difficult with up to 40% negative MRI. Our main objective is to improve the detection of FCD2from conventional sequences, to assess the relevance of increased magnetic field and validate new tools for detection, in particular by identifying sulcal abnormalities associated with FCD2 automatically and visually. This study was carried out from one of the largest cohort of patients (> 80 patients) with histologically proven FCD2. The evaluation of the frequency of each MR signs showed that, although no abnormality is seen in 41% of cases, the different signs in patients with a positive MRI were never isolated and the combination of the 3 most suggestive signs of FCD2 (cortical thickening, bluring of the gray-white matter interface and "transmantle sign") was found in 27 patients (64%), indicating that MRI can be very suggestive. By increasing the magnetic field from 1.5 to 3T MRI detection rate is only slightly changed but characterization of FCD2 is improved thanks to a better visualization of the " transmantle sign " considered as a MR signature of FCD2. The automated sulcus analysis based on the calculation of a new parameter called "sulcal energy" identifies abnormal sulcal patterns in patients with FCD2 in the central region in comparison to healthy subjects. This result underlines the importance of the identification of sulci and could provide an additional criterion for detecting and locating the lesion in patients with negative MRI. Finally, the visual analysis of sulci by 3D reformatting of the cortex allowed us to describe a new MR sign of FCD2 in the central region: a sulcal pattern called the "Power Button Sign". Given its excellent reproducibility and specificity, it could be used as a new major diagnostic criterion of FCD2 in the central region. All these results contribute to the better understanding of the developmental processes involved in the pathophysiology of FCD2 and offers many opportunities for improving their MR detection.
54

Optimalizace chirurgické léčby epilepsie v dětském věku / Optimizing of epilepsy surgery in paediatric patients

Bělohlávková, Anežka January 2021 (has links)
Optimizing of Epilepsy Surgery in Paediatric Patients Abstract Epilepsy surgery represents an effective treatment of intractable focal epilepsy. The presented work aims to describe the state of the art and enhance diagnostic and therapeutic algorithm in paediatric patients. The ultimate goal is to improve the outcome of surgeries. The work depicts the evolution of the paediatric epilepsy surgery program in Motol Epilepsy Center over the course of years 2000-2017. Complexity of patients (younger age, epileptogenic zone in proximity of eloquent cortex, multifocal MRI findings) and surgeries (hemispherotomy) alike increased over time. However, the outcomes in terms of postoperative seizure-freedom and complications remained stable. Cognitive abilities of patients improved by 9.1 IQ/DQ points one year after surgery. Patients with preexisting intellectual deficit reached the most significant increase. We developed a novel paradigm of intraoperative cortical electrical stimulation mapping. Furthermore, we introduced a technique employing visual detection of SEEG electrodes during the surgery. These procedures aim to achieve a complete resection while avoiding complications. We developed and standardized Czech versions of questionnaires IPES a QOLIE-AD-48 assessing quality of life in children with epilepsy. We...
55

The Journey from Intergroup Emnity to Peaceful Conflict Handling. Peacebuilding Experiences of local NGOs in the former Yugoslavia: Multiple Approaches for Undermining Intergroup Animosities and Dealing With Differences.

Schaefer, Christoph Daniel January 2011 (has links)
Classical approaches to conflict resolution assume that inducing conflict parties to analyse conflict constellations precipitates that the disputants recognise mutually shared needs or interests. Partially in critical reaction towards this assumption, a more recently emerging approach envisages setting up a communicative framework within which the conflict parties are supposed to harmonise their conceptualisations of the conflict. This dissertation, in contrast, argues that work within the frameworks of these classes of approaches is impolitic as long as war-related hostilities stay intact, since conflict parties which see the existence of the adversary as the core of the problem are unlikely to engage in a process of open communication or open analysis, so that trustbuilding is a sine qua non. Practice experiences of local NGOs in the former Yugoslavia suggest that the following activities can be conducive to trustbuilding: 1) supporting exchanges on personalising information, so that the internal heterogeneity of the opponent¿s group is rendered visible; 2) bringing intergroup iii commonalities to the foreground, either through cooperation on shared aspirations, or by unearthing interpersonal overlaps e.g. common feelings, values, and war-related experiences; 3) undermining the imagination of the own side¿s moral superiority by fostering the recognition of crimes and suffering inflicted by the own side. For those cultural and religious differences which persist after basic trustbuilding, a contingency approach is proposed: 1) Fostering the exploration of commonalities and differences; 2) If disagreements remain despite a better basic understanding, tolerance of these difference can be based on a better understanding of the values¿ background, and on an acceptance of differing beliefs as equal in valence; 3) Supporting the discovery of joint values to raise awareness for options of cohabitation with differences; disagreements which cannot be solved might be continued within an accepted communicative framework based on these shared values.
56

Impacts of (un)civil discourse by organized groups on local governance in sustainable development projects

Cowgill, Kimberly Hodge 19 October 2015 (has links)
Anecdotal evidence in the media and from personal conversations suggests that inflammatory rhetoric in the collaborative governance setting is increasing, especially during public meetings about sustainable development projects. Planners, mediators, facilitators, and government officials are facing a shutting down of public deliberation by "new activists" who are engaging in public forums in very emotional and uncompromising ways. This dissertation is a direct examination of actions by new activists. It includes two case studies in Roanoke, Virginia, as well as a broader look at the inflammatory rhetoric and disruptions in local public meetings now occurring across the country. / Ph. D.
57

Pastoral care and counselling of the person in chronic pain

Jacobs, Alvean Illinois 11 1900 (has links)
People expenencmg chronic pain encounter increases m needs and endure the consequences of failure to satisfy needs. In much of the management of people with chronic pain, chronic pain is considered an abstract phenomenon with little attention given to the human experience. Numerous literature focus on a mechanistic reductionistic approach in management of chronic pain. Most literature is written by medical practitioners, nurses and psychologists from a health-care oriented methodology, whereas minimal research literature was contributed from a pastoral care and counselling perspective. This dissertation explores the needs and feelings of people with chronic pain to identify their needs at the various developmental stages of their pain experience, and within their relevant ecosystems, in order to develop a pastoral response. / Practical Theology / M. Th. (Practical Theology)
58

Os efeitos da estimulação magnética transcraniana repetitiva (EMTr) aplicada sobre o córtex motor de pacientes com síndrome complexa de dor regional / The effects of repetitive transcranial magnetic stimulation (r-TMS) over the motor cortex on complex regional pain syndrome patients

Picarelli, Helder 17 April 2009 (has links)
Introdução e objetivos: Estudos recentes sugerem que a estimulação magnética transcraniana repetitiva (EMTr) aplicada sobre o córtex motor é eficaz no tratamento analgésico de doentes com dor crônica. O objetivo deste estudo foi avaliar os efeitos da aplicação da EMTr sobre o córtex motor, utilizada como co-intervenção terapêutica no tratamento de pacientes com síndrome complexa de dor regional (SCDR) refratária aos tratamentos convencionais. Métodos: Vinte e três doentes com SCDR na mão foram distribuídos aleatoriamente em dois grupos de tratamentos para receberem o tratamento padrão (analgésicos, medicações adjuvantes e terapia física) associado a dez sessões diárias e consecutivas de EMTr rápida ou estimulação magnética placebo (EMTp), aplicadas sobre a região correspondente ao córtex motor da mão acometida. Os grupos foram comparados em relação aos aspectos epidemiológicos, apresentação clínica da doença, intensidade da dor, alterações do humor, qualidade de vida e função do membro acometido até noventa dias após a conclusão do tratamento, utilizando-se de entrevistas estruturadas, da escala visual analógicas de dor (EVA), do questionário de dor de McGuill (QM), do questionário PIQ-6 (Pain Inpact Questionnaire), do questionário DASH (Disabilities of Arm, Shoulder and Hand), do questionário SF-36 e dos questionários Hamilton para ansiedade e depressão. Resultados: Ocorreu redução significativa dos escores da EVA no grupo tratado com EMTr durante o tratamento, que durou até o sétimo dia após o encerramento das aplicações (p<0.05). A redução média da EVA no grupo tratado com EMTr foi de 4.65 cm (redução de 50.9% dos escores de dor), estatisticamente superior ao grupo tratado com placebo, no qual a redução foi de 2.18 cm (redução de 24.7%). A diminuição dos escores de dor na EVA foi independente de outras variáveis em estudo, exceto pela melhora no domínio sete do questionário SF-36 (aspectos emocionais). Conclusões: A aplicação de EMTr rápida sobre a área motora da mão de doentes com SCDR, associada a um programa de tratamento padrão, resulta em diminuição maior da percepção espontânea da dor quando comparada ao efeito do tratamento padrão isolado, independentemente de outros possíveis efeitos da EMTr sobre o humor, função do membro acometido ou qualidade de vida / Background and aims: There are many evidences that repetitive transcranial magnetic stimulation (r-TMS) of the motor cortex is effective in relief of chronic pain. The aim of this study was to evaluate the analgesic effects of r-TMS in patients with refractory CRPS. Methods: Twenty-three patients presenting with complex regional pain syndrome (CRPS) of the hand were randomly selected and treated with conventional treatment (analgesics, adjuvant medications and physical therapy) plus sham-TMS or r-TMS to the motor cortex opposite the affected limb: 100% MT, 10 hz, 10 s trains, 25 trains daily, 10 daily sessions. The Visual Analogical Scale of Pain (VAS), McGill Questionnaire, Pain Impact Questionnaire (PIQ-6), Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH), Hamilton Depression and Anxiety Rating Scales and SF-36 Questionnaire were the instruments used for the evaluation. The groups were comparable with regards to socio-demographics, mood and pain intensity. Evaluations were performed before, during TMS treatment and up to three months the end of the treatment. Results: There was a significant reduction in VAS scores favoring the r-TMS group up to the seventh follow-up day (p <0.05). The mean reduction in the rTMS group was of 4.65 cm (fall of 50.9%) against 2.18 cm (fall of 24.7%) in sham group during treatment. Improvement in VAS scores was independent of other variables, except for improvement in emotional aspects in the SF-36. Conclusions: During r-TMS sessions there was significant and positive improvement in pain experience of CRPS patients regardless of mood, function or quality of life effects
59

Pastoral care and counselling of the person in chronic pain

Jacobs, Alvean Illinois 11 1900 (has links)
People expenencmg chronic pain encounter increases m needs and endure the consequences of failure to satisfy needs. In much of the management of people with chronic pain, chronic pain is considered an abstract phenomenon with little attention given to the human experience. Numerous literature focus on a mechanistic reductionistic approach in management of chronic pain. Most literature is written by medical practitioners, nurses and psychologists from a health-care oriented methodology, whereas minimal research literature was contributed from a pastoral care and counselling perspective. This dissertation explores the needs and feelings of people with chronic pain to identify their needs at the various developmental stages of their pain experience, and within their relevant ecosystems, in order to develop a pastoral response. / Philosophy, Practical and Systematic Theology / M. Th. (Practical Theology)
60

Os efeitos da estimulação magnética transcraniana repetitiva (EMTr) aplicada sobre o córtex motor de pacientes com síndrome complexa de dor regional / The effects of repetitive transcranial magnetic stimulation (r-TMS) over the motor cortex on complex regional pain syndrome patients

Helder Picarelli 17 April 2009 (has links)
Introdução e objetivos: Estudos recentes sugerem que a estimulação magnética transcraniana repetitiva (EMTr) aplicada sobre o córtex motor é eficaz no tratamento analgésico de doentes com dor crônica. O objetivo deste estudo foi avaliar os efeitos da aplicação da EMTr sobre o córtex motor, utilizada como co-intervenção terapêutica no tratamento de pacientes com síndrome complexa de dor regional (SCDR) refratária aos tratamentos convencionais. Métodos: Vinte e três doentes com SCDR na mão foram distribuídos aleatoriamente em dois grupos de tratamentos para receberem o tratamento padrão (analgésicos, medicações adjuvantes e terapia física) associado a dez sessões diárias e consecutivas de EMTr rápida ou estimulação magnética placebo (EMTp), aplicadas sobre a região correspondente ao córtex motor da mão acometida. Os grupos foram comparados em relação aos aspectos epidemiológicos, apresentação clínica da doença, intensidade da dor, alterações do humor, qualidade de vida e função do membro acometido até noventa dias após a conclusão do tratamento, utilizando-se de entrevistas estruturadas, da escala visual analógicas de dor (EVA), do questionário de dor de McGuill (QM), do questionário PIQ-6 (Pain Inpact Questionnaire), do questionário DASH (Disabilities of Arm, Shoulder and Hand), do questionário SF-36 e dos questionários Hamilton para ansiedade e depressão. Resultados: Ocorreu redução significativa dos escores da EVA no grupo tratado com EMTr durante o tratamento, que durou até o sétimo dia após o encerramento das aplicações (p<0.05). A redução média da EVA no grupo tratado com EMTr foi de 4.65 cm (redução de 50.9% dos escores de dor), estatisticamente superior ao grupo tratado com placebo, no qual a redução foi de 2.18 cm (redução de 24.7%). A diminuição dos escores de dor na EVA foi independente de outras variáveis em estudo, exceto pela melhora no domínio sete do questionário SF-36 (aspectos emocionais). Conclusões: A aplicação de EMTr rápida sobre a área motora da mão de doentes com SCDR, associada a um programa de tratamento padrão, resulta em diminuição maior da percepção espontânea da dor quando comparada ao efeito do tratamento padrão isolado, independentemente de outros possíveis efeitos da EMTr sobre o humor, função do membro acometido ou qualidade de vida / Background and aims: There are many evidences that repetitive transcranial magnetic stimulation (r-TMS) of the motor cortex is effective in relief of chronic pain. The aim of this study was to evaluate the analgesic effects of r-TMS in patients with refractory CRPS. Methods: Twenty-three patients presenting with complex regional pain syndrome (CRPS) of the hand were randomly selected and treated with conventional treatment (analgesics, adjuvant medications and physical therapy) plus sham-TMS or r-TMS to the motor cortex opposite the affected limb: 100% MT, 10 hz, 10 s trains, 25 trains daily, 10 daily sessions. The Visual Analogical Scale of Pain (VAS), McGill Questionnaire, Pain Impact Questionnaire (PIQ-6), Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH), Hamilton Depression and Anxiety Rating Scales and SF-36 Questionnaire were the instruments used for the evaluation. The groups were comparable with regards to socio-demographics, mood and pain intensity. Evaluations were performed before, during TMS treatment and up to three months the end of the treatment. Results: There was a significant reduction in VAS scores favoring the r-TMS group up to the seventh follow-up day (p <0.05). The mean reduction in the rTMS group was of 4.65 cm (fall of 50.9%) against 2.18 cm (fall of 24.7%) in sham group during treatment. Improvement in VAS scores was independent of other variables, except for improvement in emotional aspects in the SF-36. Conclusions: During r-TMS sessions there was significant and positive improvement in pain experience of CRPS patients regardless of mood, function or quality of life effects

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