399 research outputs found

    FADTTSter: Accelerating hypothesis testing with functional analysis of diffusion tensor tract statistics

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    Functional Analysis of Diffusion Tensor Tract Statistics (FADTTS) is a toolbox for analysis of white matter (WM) fiber tracts. It allows associating diffusion properties along major WM bundles with a set of covariates of interest, such as age, diagnostic status and gender, and the structure of the variability of these WM tract properties. However, to use this toolbox, a user must have an intermediate knowledge in scripting languages (MATLAB). FADTTSter was created to overcome this issue and make the statistical analysis accessible to any non-technical researcher. FADTTSter is actively being used by researchers at the University of North Carolina. FADTTSter guides non-technical users through a series of steps including quality control of subjects and fibers in order to setup the necessary parameters to run FADTTS. Additionally, FADTTSter implements interactive charts for FADTTS' outputs. This interactive chart enhances the researcher experience and facilitates the analysis of the results. FADTTSter's motivation is to improve usability and provide a new analysis tool to the community that complements FADTTS. Ultimately, by enabling FADTTS to a broader audience, FADTTSter seeks to accelerate hypothesis testing in neuroimaging studies involving heterogeneous clinical data and diffusion tensor imaging. This work is submitted to the Biomedical Applications in Molecular, Structural, and Functional Imaging conference. The source code of this application is available in NITRC

    CIVILITY: Cloud based interactive visualization of tractography brain connectome

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    Cloud based Interactive Visualization of Tractography Brain Connectome (CIVILITY) is an interactive visualization tool of brain connectome in the cloud. This application submits tasks to remote computing grids were the CIVILITY-tractography pipeline is deployed. The application will list the running tasks for the user and once a task is completed the brain connectome is visualized using Hierarchical Edge Bundling. The analysis pipeline uses FSL tools (bedpostx and probtrackx2) to generate a triangular matrix indicating the connectivity strength between different regions in the brain. This work is motivated by medical applications in which expensive computational tasks such as brain connectivity is needed and to provide a state of the art visualization tool of Brain Connectome. This work does not contribute any novelty with respect to the visualization methodology, is rather a new resource for the neuroimaging community. This work is submitted to the SPIE Biomedical Applications in Molecular, Structural, and Functional Imaging conference. The source code of this application is available in NITRC

    Problemas y propuestas de mejora en la atención sanitaria a los inmigrantes económicos

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    ResumenObjetivosAnalizar los problemas que existen en la atención sanitaria a los inmigrantes económicos en opinión de profesionales sociosanitarios, de la administración sanitaria y de inmigrantes, así como conocer y priorizar las propuestas de los profesionales para mejorar dicha atención.MétodosEstudio descriptivo de enfoque cualitativo realizado en Mallorca. Se han realizado tres grupos focales y tres grupos nominales con profesionales de atención primaria y especializada, dos entrevistas semiestructuradas a dos miembros de la administración sanitaria, uno de la Administración autonómica y otro de la Administración central, y doce entrevistas semiestructuradas a inmigrantes económicos identificados a partir de informantes clave.ResultadosEl incremento del número de inmigrantes económicos es percibido por los profesionales y por la administración con una sensación de llegada masiva. Los principales problemas identificados han sido las restricciones de acceso, el seguimiento de estos pacientes, y la falta de entrenamiento en medicina tropical. Los inmigrantes, en cambio, están más preocupados por regularizar su situación y por el acceso a la vivienda. La primera propuesta de los profesionales es su formación en medicina tropical. La Administración autonómica prioriza el acceso a los servicios sanitarios y la búsqueda activa de problemas de salud en esta población, mientras que la Administración central aboga en primer lugar por la regularización de todos los inmigrantes.ConclusionesLas principales barreras en la atención sanitaria a los inmmigrantes económicos son, en opinión de los profesionales sociosanitarios, las restricciones de acceso, el seguimiento clínico y la falta de entrenamiento en medicina tropical, y para mejorar esta situación los profesionales demandan formación. Las prioridades de las Administraciones autonómica y central no son coincidentes. Finalmente, para los inmigrantes económicos, la atención sanitaria no parece ser una prioridad.SummaryObjectivesTo analyse existing problems in health care to economic immigrants from the point of view of health and social professionals, health authorities and economic immigrants and to know which will be their proposals and priorities to improve economic immigrants’s health assistance.MethodsQualitative approach study made in Majorca island. (Spain). Three focus groups and three nominal groups with health and social workers from primary health care and hospital services were carried out as well as two partially structured interviews to health authorities, one Autonomic Authority and one Governmental Authority, and twelve partially structured interviews to economic immigrants identified trough key informants.ResultsHealth and social workers perceive the increase in the number of economic immigrants as a massive arrival. The main problems identified are: access restrictions to public helath services for economic immigrants, the follow-up of these patients and diagnostic difficulties because lack of training in tropical medicine. Health and social workers’s first proposal for improving this situation is their own training in tropical medicine. Autonomic Authority priorities are to garantiee access to public health services for all immigrants and to look actively for health problems in these population. Governmental Authority, instead, holds the legalization for all. In fact, economic immigrants are not concerned on health care because legalization and houssing problems.ConclusionsThe main barriers identified by health and social workers in health care to economic immigrants are: access restrictions, follow-up and lack of training in tropical medicine. Health and social first proposal to improve this situation is their own training in tropical medicine while Autonomic and Central Authorities’s priorities are not the same. For economic inmigrants, health assistance is not their biggest concern

    Autotract: Automatic cleaning and tracking of fibers

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    We propose a new tool named Autotract to automate fiber tracking in diffusion tensor imaging (DTI). Autotract uses prior knowledge from a source DTI and a set of corresponding fiber bundles to extract new fibers for a target DTI. Autotract starts by aligning both DTIs and uses the source fibers as seed points to initialize a tractography algorithm. We enforce similarity between the propagated source fibers and automatically traced fibers by computing metrics such as fiber length and fiber distance between the bundles. By analyzing these metrics, individual fiber tracts can be pruned. As a result, we show that both bundles have similar characteristics. Additionally, we compare the automatically traced fibers against bundles previously generated and validated in the target DTI by an expert. This work is motivated by medical applications in which known bundles of fiber tracts in the human brain need to be analyzed for multiple datasets

    Análisis de envejecimiento en paneles sándwich de madera/ Ageing tests study on wood-based sandwich panels

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    Los paneles sándwich de madera son un producto de creciente aplicación en la edificación de nuestro país. Este ascendente uso del material debe estar acompañado de las garantías necesarias avaladas por un estudio previo de sus prestaciones. Como es preceptivo y entre otros, se evalúa su durabilidad frente a las condiciones climatológicas, clave en los productos derivados de la madera, acorde a la normativa actual definida con tal fin, la Guía ETAG 016. Sin embargo, debido a la clase de uso del material, se ha detectado que dicha normativa tal y como está concebida no es capaz de valorar su envejecimiento adecuadamente. En este trabajo se proponen ensayos alternativos al establecido tras exhaustivos aná- lisis que recrean las condiciones reales de uso y más acordes a los productos de madera. Se concluye que la incorporación de una lámina impermeable, pero permeable al vapor de agua hacia el exterior, como las utilizadas en el montaje, aportan el mejor procedimiento de ensayo. Composite lightweight wood panels are being increasingly used in construction in Spain. Their growing use should be accompanied by necessary guarantees based on studies of their properties. As it is prescriptive and in addition to others tests, in the present work is examinated the durability of these panels when exposed to the climatic conditions, a characteristic of great importance for wood products, according to Guide ETAG 016, the current standard defining the ageing tests to be used. However, due to the use class of this material, there are indications that the testing outlined in this Guide is inappropriate for assessing the ageing of wood-based sandwich panels. Alternative tests are here proposed that recreate rather better the real conditions under which these products are used. Covering the samples in a waterproof sheeting permeable to the outward movement of water vapour, which is in fact used in the installation, provided the best procedure for testing these panels

    MultisegPipeline: Automatic tissue segmentation of brain MR images with subject-specific atlases

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    Automated segmentation and labeling of individual brain anatomical regions is challenging due to individual structural variability. Although, atlas-based segmentation has shown its potential for both tissue and structure segmentation, the inherent natural variability as well as disease-related changes in MR appearance is often inappropriately represented by a single atlas image. In order to have a more accurate representation, several atlases may be used for the segmentation task in a given neuroimaging study. In this paper, we present the MultisegPipeline, it uses multiple atlases that have been visually inspected and capture the expected variability in a neonatal population. The MultisegPipeline transfers the labeled regions from each atlas to the target image using deformable registration (ANTs or QuickSilver is available for this task). Additionally, the set of labels are merged using a label fusion technique that reduces the errors produced by the registration. The final output is a single label map that combines the results produced by all atlases into a consensus solution. In our study, the MultisegPipeline is used to segment brain MR images from 31 infants, a leave-one-out strategy was used to test our framework. The average dice score coefficient was 0.89

    Mechanistic studies on the photogeneration of o- and p-xylylenes from α,α'-dichloroxylenes

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    Two-colour two-laser techniques have unambiguously proved that photolysis of the o-/p-(chloromethyl)benzyl radical leads to the sequential two-photon generation of o-/pxylylene from α,α'-dichloro-o-/p-xylene.Perez Prieto, Julia, [email protected]

    TRAFIC: Fiber tract classification using deep learning

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    We present TRAFIC, a fully automated tool for the labeling and classification of brain fiber tracts. TRAFIC classifies new fibers using a neural network trained using shape features computed from previously traced and manually corrected fiber tracts. It is independent from a DTI Atlas as it is applied to already traced fibers. This work is motivated by medical applications where the process of extracting fibers from a DTI atlas, or classifying fibers manually is time consuming and requires knowledge about brain anatomy. With this new approach we were able to classify traced fiber tracts obtaining encouraging results. In this report we will present in detail the methods used and the results achieved with our approach

    Improved heuristic drift elimination with magnetically-aided dominant directions (MiHDE) for pedestrian navigation in complex buildings

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    The main problem of pedestrian dead-reckoning (PDR) using only a body-attached inertial measurement unit is the accumulation of heading errors. The heading provided by magnetometers in indoor buildings is in general not reliable and therefore it is commonly not used. Recently, a new method was proposed called heuristic drift elimination (HDE) that minimises the heading error when navigating in buildings. It assumes that the majority of buildings have their corridors parallel to each other, or they intersect at right angles, and consequently most of the time the person walks along a straight path with a heading constrained to one of the four possible directions. In this article we study the performance of HDE-based methods in complex buildings, i.e. with pathways also oriented at 45°, long curved corridors, and wide areas where non-oriented motion is possible. We explain how the performance of the original HDE method can be deteriorated in complex buildings, and also, how severe errors can appear in the case of false matches with the building's dominant directions. Although magnetic compassing indoors has a chaotic behaviour, in this article we analyse large data-sets in order to study the potential use that magnetic compassing has to estimate the absolute yaw angle of a walking person. Apart from these analysis, this article also proposes an improved HDE method called Magnetically-aided Improved Heuristic Drift Elimination (MiHDE), that is implemented over a PDR framework that uses foot-mounted inertial navigation with an extended Kalman filter (EKF). The EKF is fed with the MiHDE-estimated orientation error, gyro bias corrections, as well as the confidence over that corrections. We experimentally evaluated the performance of the proposed MiHDE-based PDR method, comparing it with the original HDE implementation. Results show that both methods perform very well in ideal orthogonal narrow-corridor buildings, and MiHDE outperforms HDE for non-ideal trajectories (e.g. curved paths) and also makes it robust against potential false dominant direction matchings
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