345 research outputs found

    Managing risks and harms associated with the use of anabolic steroids

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    Background: People using AAS may adopt a range of strategies to prevent and treat adverse health conditions potentially associated with the use of these substances (AAS-HC). These strategies include seeking support from physicians, using the needle and syringe exchange programme (NSP) and seeking support from informal sources such as coaches and online forums. The process of identifying risks and harms, adopting and modifying health-related strategies is similar to the methods of risk-management employed in other fields of human activity. This approach recognises the importance of the informal body of knowledge produced by decades of AAS-related folk-pharmacology and seeks to understand harm-reduction from the users’ perspective.Objectives: The primary objective of this thesis is to investigate the strategies adopted by people using AAS to prevent and treat AAS-HC. Secondary objectives include to explore the factors associated with the adoption of health strategies and the occurrence of AAS-HC, as well as the barriers and facilitators experienced by AAS users when accessing health services and other sources of support.Methods: To achieve the objectives above, three work packages (WP) were produced as part of a mixed-methods research design. WP1 is a systematic review and meta-analysis of the prevalence of AAS users seeking support from physicians. WP2 is a cross-sectional online survey that identified AAS-HC, risk factors and health-related strategies adopted by AAS users in the UK. WP3 is a qualitative study based on in-depth interviews to discuss the experiences of AAS users and their risk-management strategies (RMS).Results: The estimated overall prevalence of AAS users seeking support from physicians is 37.1%. Higher prevalence rates were observed in studies from Australia (67.3%) and amongst clients of the NSP (54.1%), whilst the lowest was observed among adolescents (17.3%). The health conditions most commonly reported by the 883 participants of the online survey were insomnia (33.3%) and anxiety (32.2%). Most participants adopted preventive strategies such as having blood tests in the last 12 months (86.2%) and seeking a GP to treat AAS-HC (55.0%). Those who sought a GP for AAS-related information were 76% less likely to report an AAS-HC in the last 12 months. The interviews described AAS users’ RMS as a continuous process of awareness and behavioural changes. Participants described an extensive use of private health services and other sources of support to bypass the barriers experienced by AAS users engaging with the public health system.Conclusion: A large number of AAS users refrain from seeking support from physicians. Health professionals should be trained to recognise and manage the most common AAS-HC and help users improve their RMS. Further studies should investigate the efficacy of AAS-related RMS and the subpopulations of AAS users more likely to experience AAS-HC and less likely to engage with health services.<br/

    Computer Vision and Architectural History at Eye Level:Mixed Methods for Linking Research in the Humanities and in Information Technology

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    Information on the history of architecture is embedded in our daily surroundings, in vernacular and heritage buildings and in physical objects, photographs and plans. Historians study these tangible and intangible artefacts and the communities that built and used them. Thus valuableinsights are gained into the past and the present as they also provide a foundation for designing the future. Given that our understanding of the past is limited by the inadequate availability of data, the article demonstrates that advanced computer tools can help gain more and well-linked data from the past. Computer vision can make a decisive contribution to the identification of image content in historical photographs. This application is particularly interesting for architectural history, where visual sources play an essential role in understanding the built environment of the past, yet lack of reliable metadata often hinders the use of materials. The automated recognition contributes to making a variety of image sources usable forresearch.<br/

    Autoencoder-based Image Recommendation for Lung Cancer Characterization

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    Neste projeto, temos como objetivo desenvolver um sistema de IA que recomende um conjunto de casos relativos (passados) para orientar a tomada de decisão do médico. Objetivo: A ambição é desenvolver um modelo de aprendizado baseado em IA para caracterização de câncer de pulmão, a fim de auxiliar na rotina clínica. Considerando a complexidade dos fenômenos biológicos que ocorrem durante o desenvolvimento do câncer, as relações entre eles e as manifestações visuais capturadas pela tomografia computadorizada (CT) têm sido exploradas nos últimos anos. No entanto, devido à falta de robustez dos métodos atuais de aprendizado profundo, essas correlações são frequentemente consideradas espúrias e se perdem quando confrontadas com dados coletados a partir de distribuições alteradas: diferentes instituições, características demográficas ou até mesmo estágios de desenvolvimento do câncer.In this project, we aim to develop an AI system that recommends a set of relative (past) cases to guide the decision-making of the clinician. Objective: The ambition is to develop an AI-based learning model for lung cancer characterization in order to assist in clinical routine. Considering the complexity of the biological phenomenat hat occur during cancer development, relationships between these and visual manifestations captured by CT have been explored in recent years; however, given the lack of robustness of current deep learning methods, these correlations are often found spurious and get lost when facing data collected from shifted distributions: different institutions, demographics or even stages of cancer development

    Computer Vision and Architectural History at Eye Level:Mixed Methods for Linking Research in the Humanities and in Information Technology

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    Information on the history of architecture is embedded in our daily surroundings, in vernacular and heritage buildings and in physical objects, photographs and plans. Historians study these tangible and intangible artefacts and the communities that built and used them. Thus valuableinsights are gained into the past and the present as they also provide a foundation for designing the future. Given that our understanding of the past is limited by the inadequate availability of data, the article demonstrates that advanced computer tools can help gain more and well-linked data from the past. Computer vision can make a decisive contribution to the identification of image content in historical photographs. This application is particularly interesting for architectural history, where visual sources play an essential role in understanding the built environment of the past, yet lack of reliable metadata often hinders the use of materials. The automated recognition contributes to making a variety of image sources usable forresearch.<br/

    DEEP-AD: The deep learning model for diagnostic classification and prognostic prediction of alzheimer's disease

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    In terms of context, the aim of this dissertation is to aid neuroradiologists in their clinical judgment regarding the early detection of AD by using DL. To that aim, the system design research methodology is suggested in this dissertation for achieving three goals. The first goal is to investigate the DL models that have performed well at identifying patterns associated with AD, as well as the accuracy so far attained, limitations, and gaps. A systematic review of the literature (SLR) revealed a shortage of empirical studies on the early identification of AD through DL. In this regard, thirteen empirical studies were identified and examined. We concluded that three-dimensional (3D) DL models have been generated far less often and that their performance is also inadequate to qualify them for clinical trials. The second goal is to provide the neuroradiologist with the computer-interpretable information they need to analyze neuroimaging biomarkers. Given this context, the next step in this dissertation is to find the optimum DL model to analyze neuroimaging biomarkers. It has been achieved in two steps. In the first step, eight state-of-the-art DL models have been implemented by training from scratch using end-to-end learning (E2EL) for two binary classification tasks (AD vs. CN and AD vs. stable MCI) and compared by utilizing MRI scans from the publicly accessible datasets of neuroimaging biomarkers. Comparative analysis is carried out by utilizing efficiency-effects graphs, comprehensive indicators, and ranking mechanisms. For the training of the AD vs. sMCI task, the EfficientNet-B0 model gets the highest value for the comprehensive indicator and has the fewest parameters. DenseNet264 performed better than the others in terms of evaluation matrices, but since it has the most parameters, it costs more to train. For the AD vs. CN task by DenseNet264, we achieved 100% accuracy for training and 99.56% accuracy for testing. However, the classification accuracy was still only 82.5% for the AD vs. sMCI task. In the second step, fusion of transfer learning (TL) with E2EL is applied to train the EfficientNet-B0 for the AD vs. sMCI task, which achieved 95.29% accuracy for training and 93.10% accuracy for testing. Additionally, we have also implemented EfficientNet-B0 for the multiclass AD vs. CN vs. sMCI classification task with E2EL to be used in ensemble of models and achieved 85.66% training accuracy and 87.38% testing accuracy. To evaluate the model&#8217;s robustness, neuroradiologists must validate the implemented model. As a result, the third goal of this dissertation is to create a tool that neuroradiologists may use at their convenience. To achieve this objective, this dissertation proposes a web-based application (DEEP-AD) that has been created by making an ensemble of Efficient-Net B0 and DenseNet 264 (based on the contribution of goal 2). The accuracy of a DEEP-AD prototype has undergone repeated evaluation and improvement. First, we validated 41 subjects of Spanish MRI datasets (acquired from HT Medica, Madrid, Spain), achieving an accuracy of 82.90%, which was later verified by neuroradiologists. The results of these evaluation studies showed the accomplishment of such goals and relevant directions for future research in applied DL for the early detection of AD in clinical settings.En términos de contexto, el objetivo de esta tesis es ayudar a los neurorradiólogos en su juicio clínico sobre la detección precoz de la AD mediante el uso de DL. Para ello, en esta tesis se propone la metodología de investigación de diseño de sistemas para lograr tres objetivos. El segundo objetivo es proporcionar al neurorradiólogo la información interpretable por ordenador que necesita para analizar los biomarcadores de neuroimagen. Dado este contexto, el siguiente paso en esta tesis es encontrar el modelo DL óptimo para analizar biomarcadores de neuroimagen. Esto se ha logrado en dos pasos. En el primer paso, se han implementado ocho modelos DL de última generación mediante entrenamiento desde cero utilizando aprendizaje de extremo a extremo (E2EL) para dos tareas de clasificación binarias (AD vs. CN y AD vs. MCI estable) y se han comparado utilizando escaneos MRI de los conjuntos de datos de biomarcadores de neuroimagen de acceso público. El análisis comparativo se lleva a cabo utilizando gráficos de efecto-eficacia, indicadores exhaustivos y mecanismos de clasificación. Para el entrenamiento de la tarea AD vs. sMCI, el modelo EfficientNet-B0 obtiene el valor más alto para el indicador exhaustivo y tiene el menor número de parámetros. DenseNet264 obtuvo mejores resultados que los demás en términos de matrices de evaluación, pero al ser el que tiene más parámetros, su entrenamiento es más costoso. Para la tarea AD vs. CN de DenseNet264, conseguimos una accuracy del 100% en el entrenamiento y del 99,56% en las pruebas. Sin embargo, la accuracy de la clasificación fue sólo del 82,5% para la tarea AD vs. sMCI. En el segundo paso, se aplica la fusión del aprendizaje por transferencia (TL) con E2EL para entrenar la EfficientNet-B0 para la tarea AD vs. sMCI, que alcanzó una accuracy del 95,29% en el entrenamiento y del 93,10% en las pruebas. Además, también hemos implementado EfficientNet-B0 para la tarea de clasificación multiclase AD vs. CN vs. sMCI con E2EL para su uso en conjuntos de modelos y hemos obtenido una accuracy de entrenamiento del 85,66% y una precisión de prueba del 87,38%. Para evaluar la solidez del modelo, los neurorradiólogos deben validar el modelo implementado. Como resultado, el tercer objetivo de esta disertación es crear una herramienta que los neurorradiólogos puedan utilizar a su conveniencia. Para lograr este objetivo, esta disertación propone una aplicación basada en web (DEEP-AD) que ha sido creada haciendo un ensemble de Efficient-Net B0 y DenseNet 264 (basado en la contribución del objetivo 2). La accuracy del prototipo DEEP-AD ha sido sometida a repetidas evaluaciones y mejoras. En primer lugar, validamos 41 sujetos de conjuntos de datos de MRI españoles (adquiridos de HT Medica, Madrid, España), logrando una accuracy del 82,90%, que posteriormente fue verificada por neurorradiólogos. Los resultados de estos estudios de evaluación mostraron el cumplimiento de dichos objetivos y las direcciones relevantes para futuras investigaciones en DL, aplicada en la detección precoz de la AD en entornos clínicos.Escuela de DoctoradoDoctorado en Tecnologías de la Información y las Telecomunicacione

    Computer Vision and Architectural History at Eye Level:Mixed Methods for Linking Research in the Humanities and in Information Technology

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    Information on the history of architecture is embedded in our daily surroundings, in vernacular and heritage buildings and in physical objects, photographs and plans. Historians study these tangible and intangible artefacts and the communities that built and used them. Thus valuableinsights are gained into the past and the present as they also provide a foundation for designing the future. Given that our understanding of the past is limited by the inadequate availability of data, the article demonstrates that advanced computer tools can help gain more and well-linked data from the past. Computer vision can make a decisive contribution to the identification of image content in historical photographs. This application is particularly interesting for architectural history, where visual sources play an essential role in understanding the built environment of the past, yet lack of reliable metadata often hinders the use of materials. The automated recognition contributes to making a variety of image sources usable forresearch.<br/

    Estimation de cartes d'énergie du bruit apériodique de la marche humaine avec une caméra de profondeur pour la détection de pathologies et modèles légers de détection d'objets saillants basés sur l'opposition de couleurs

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    Cette thèse a pour objectif l’étude de trois problèmes : l’estimation de cartes de saillance de l’énergie du bruit apériodique de la marche humaine par la perception de profondeur pour la détection de pathologies, les modèles de détection d’objets saillants en général et les modèles légers en particulier par l’opposition de couleurs. Comme première contribution, nous proposons un système basé sur une caméra de profondeur et un tapis roulant, qui analyse les parties du corps du patient ayant un mouvement irrégulier, en termes de périodicité, pendant la marche. Nous supposons que la marche d'un sujet sain présente n'importe où dans son corps, pendant les cycles de marche, un signal de profondeur avec un motif périodique sans bruit. La présence de bruit et son importance peuvent être utilisées pour signaler la présence et l'étendue de pathologies chez le sujet. Notre système estime, à partir de chaque séquence vidéo, une carte couleur de saillance montrant les zones de fortes irrégularités de marche, en termes de périodicité, appelées énergie de bruit apériodique, de chaque sujet. Notre système permet aussi de détecter automatiquement les cartes des individus sains et ceux malades. Nous présentons ensuite deux approches pour la détection d’objets saillants. Bien qu’ayant fait l’objet de plusieurs travaux de recherche, la détection d'objets saillants reste un défi. La plupart des modèles traitent la couleur et la texture séparément et les considèrent donc implicitement comme des caractéristiques indépendantes, à tort. Comme deuxième contribution, nous proposons une nouvelle stratégie, à travers un modèle simple, presque sans paramètres internes, générant une carte de saillance robuste pour une image naturelle. Cette stratégie consiste à intégrer la couleur dans les motifs de texture pour caractériser une micro-texture colorée, ceci grâce au motif ternaire local (LTP) (descripteur de texture simple mais puissant) appliqué aux paires de couleurs. La dissemblance entre chaque paire de micro-textures colorées est calculée en tenant compte de la non-linéarité des micro-textures colorées et en préservant leurs distances, donnant une carte de saillance intermédiaire pour chaque espace de couleur. La carte de saillance finale est leur combinaison pour avoir des cartes robustes. Le développement des réseaux de neurones profonds a récemment permis des performances élevées. Cependant, il reste un défi de développer des modèles de même performance pour des appareils avec des ressources limitées. Comme troisième contribution, nous proposons une nouvelle approche pour un modèle léger de réseau neuronal profond de détection d'objets saillants, inspiré par les processus de double opposition du cortex visuel primaire, qui lient inextricablement la couleur et la forme dans la perception humaine des couleurs. Notre modèle proposé, CoSOV1net, est entraîné à partir de zéro, sans utiliser de ``backbones'' de classification d'images ou d'autres tâches. Les expériences sur les ensembles de données les plus utilisés et les plus complexes pour la détection d'objets saillants montrent que CoSOV1Net atteint des performances compétitives avec des modèles de l’état-de-l’art, tout en étant un modèle léger de détection d'objets saillants et pouvant être adapté aux environnements mobiles et aux appareils à ressources limitées.The purpose of this thesis is to study three problems: the estimation of saliency maps of the aperiodic noise energy of human gait using depth perception for pathology detection, and to study models for salient objects detection in general and lightweight models in particular by color opposition. As our first contribution, we propose a system based on a depth camera and a treadmill, which analyzes the parts of the patient's body with irregular movement, in terms of periodicity, during walking. We assume that a healthy subject gait presents anywhere in his (her) body, during gait cycles, a depth signal with a periodic pattern without noise. The presence of noise and its importance can be used to point out presence and extent of the subject’s pathologies. Our system estimates, from each video sequence, a saliency map showing the areas of strong gait irregularities, in terms of periodicity, called aperiodic noise energy, of each subject. Our system also makes it possible to automatically detect the saliency map of healthy and sick subjects. We then present two approaches for salient objects detection. Although having been the subject of many research works, salient objects detection remains a challenge. Most models treat color and texture separately and therefore implicitly consider them as independent feature, erroneously. As a second contribution, we propose a new strategy through a simple model, almost without internal parameters, generating a robust saliency map for a natural image. This strategy consists in integrating color in texture patterns to characterize a colored micro-texture thanks to the local ternary pattern (LTP) (simple but powerful texture descriptor) applied to the color pairs. The dissimilarity between each colored micro-textures pair is computed considering non-linearity from colored micro-textures and preserving their distances. This gives an intermediate saliency map for each color space. The final saliency map is their combination to have robust saliency map. The development of deep neural networks has recently enabled high performance. However, it remains a challenge to develop models of the same performance for devices with limited resources. As a third contribution, we propose a new approach for a lightweight salient objects detection deep neural network model, inspired by the double opponent process in the primary visual cortex, which inextricably links color and shape in human color perception. Our proposed model, namely CoSOV1net, is trained from scratch, without using any image classification backbones or other tasks. Experiments on the most used and challenging datasets for salient objects detection show that CoSOV1Net achieves competitive performance with state-of-the-art models, yet it is a lightweight detection model and it is a salient objects detection that can be adapted to mobile environments and resource-constrained devices

    Computer Vision and Architectural History at Eye Level:Mixed Methods for Linking Research in the Humanities and in Information Technology

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    Information on the history of architecture is embedded in our daily surroundings, in vernacular and heritage buildings and in physical objects, photographs and plans. Historians study these tangible and intangible artefacts and the communities that built and used them. Thus valuableinsights are gained into the past and the present as they also provide a foundation for designing the future. Given that our understanding of the past is limited by the inadequate availability of data, the article demonstrates that advanced computer tools can help gain more and well-linked data from the past. Computer vision can make a decisive contribution to the identification of image content in historical photographs. This application is particularly interesting for architectural history, where visual sources play an essential role in understanding the built environment of the past, yet lack of reliable metadata often hinders the use of materials. The automated recognition contributes to making a variety of image sources usable forresearch.<br/

    Mathematical modeling of Lynch syndrome carcinogenesis

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    Cancer is one of the leading causes of disease-related death worldwide. In recent years, large amounts of data on cancer genetics and molecular characteristics have become available and accumulated with increasing speed. However, the current understanding of cancer as a disease is still limited by the lack of suitable models that allow interpreting these data in proper ways. Thus, the highly interdisciplinary research field of mathematical oncology has evolved to use mathematics, modeling, and simulations to study cancer with the overall goal to improve clinical patient care. This dissertation aims at developing mathematical models and tools for different spatial scales of cancer development at the example of colorectal cancer in Lynch syndrome, the most common inherited colorectal cancer predisposition syndrome. We derive model-driven approaches for carcinogenesis at the DNA, cell, and crypt level, as well as data-driven methods for cancer-immune interactions at the DNA level and for the evaluation of diagnostic procedures at the Lynch syndrome population level. The developed models present an important step toward an improved understanding of hereditary cancer as a disease aiming at rapid implementation into clinical management guidelines and into the development of novel, innovative approaches for prevention and treatment

    Mixing Methods: Practical Insights from the Humanities in the Digital Age

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    The digital transformation is accompanied by two simultaneous processes: digital humanities challenging the humanities, their theories, methodologies and disciplinary identities, and pushing computer science to get involved in new fields. But how can qualitative and quantitative methods be usefully combined in one research project? What are the theoretical and methodological principles across all disciplinary digital approaches? This volume focusses on driving innovation and conceptualising the humanities in the 21st century. Building on the results of 10 research projects, it serves as a useful tool for designing cutting-edge research that goes beyond conventional strategies
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