Search results for "Image"
showing 10 items of 6818 documents
Exploiting historical rainfall and landslide data in a spatial database for the derivation of critical rainfall thresholds
2017
Critical rainfall thresholds for landslides are powerful tools for preventing landslide hazard. The thresholds are commonly estimated empirically starting from rainfall events that triggered landslides in the past. The creation of the appropriate rainfall–landslide database is one of the main efforts in this approach. In fact, an accurate agreement between the landslide and rainfall information, in terms of location and timing, is essential in order to correctly estimate the rainfall–landslide relationships. A further issue is taking into account the average moisture conditions prior the triggering event, which reasonably may be crucial in determining the sufficient amount of precipitation.…
Progress in electron microscopic diagnostics: semi-quantitative determination of precipitable calcium in different cell types of the organ of Corti i…
1991
Potassium antimonate was used to precipitate calcium in the cochlea of the guinea-pig. The distribution of the calcium antimonate precipitates was analysed by electron microscopy. The precipitate density was determined in different cell types in the organ of Corti by counting the number of calcium binding sites in a 10-micron 2 area. The size of the precipitates varied considerably, and thus the relative amount of the precipitable calcium was estimated only semi-quantitatively. As the prominent carbon signal is superimposed over the nearby small Ca(2+)-edge signals, the combined signal of the antimony M4,5-edge and the oxygen K-edge of the calcium antimonate salt formed was chosen for the s…
Use of electron spectroscopic imaging to determine element composition of the melanin granules in the stria vascularis of the guinea pig.
1998
Electron spectroscopic imaging (ESI) was used to analyze the element content of melanin granules in the stria vascularis seen in ultrathin sections of Spurr-embedded cochleae of the guinea pig. To determine element composition, ESI images were taken at different ionization edges, and non-specific background signals were subtracted digitally by an image processing system. The presence of calcium and nitrogen in the melanin granules could be demonstrated clearly. The calcium identified in the melanin granules was then compared with the spatial distributions of calcium binding sites after the application of an antimonate precipitation method, which was used to localize loosely bound calcium. D…
Estudio hospitalario del vértigo y mareo: aspectos clínicos y radiológicos
2020
Esta tesis doctoral trabaja sobre pacientes remitidos a cualquier especialidad de un hospital sin unidad de otoneurología por los síntomas vértigo y mareo. En una primera parte se analizan sus características demográficas y clínicas y se evalúan las derivaciones con el fin de obtener datos que permitan mejorar la calidad asistencial. También se analizan las pruebas de imagen realizadas en los pacientes con vértigo y mareo, para poder determinar su utilidad y establecer recomendaciones. Las conclusiones se resumen en los siguientes puntos: En el hospital hay una tasa anual de 1,6 primeras visitas por cada 1000 habitantes debido a los síntomas vértigo y mareo. De todos los pacientes derivados…
Primera experiencia y presentación de labores investigadoras referentes a análisis de imágenes médicas para alumnos de enseñanzas medias
2019
Los Campus Científicos de Verano tienen como objetivo que los alumnos de enseñanzas medias de las opciones científico-técnicas tengan un primer contacto con la labor investigadora que se realiza en las universidades y centros de investigación. Para ello, los estudiantes participan en proyectos de una semana de duración organizados en diferentes sesiones, como la presentada en este trabajo. Enmarcado en el proyecto “Tecnología y física médicas: la innovación al servicio de la medicina”, cuyo objetivo es fomentar el interés de los alumnos en las aplicaciones tecnológicas de la ingeniería biomédica, presentamos un seminario sobre técnicas de análisis de imágenes biomédicas mediante la utilizac…
Computer Modeling for the Prediction of Thoracic Aortic Stent Graft Collapse
2011
OBJECTIVE: To assess the biomechanical implications of excessive stent protrusion into the aortic arch in relation to thoracic aortic stent graft (TASG) collapse by simulating the structural load and quantifying the fluid dynamics on the TASG wall protrusion extended into a model arch. METHODS: One-way coupled fluid-solid interaction analyses were performed to investigate the flow-induced hemodynamic and structural loads exerted on the proximal protrusion of the TASG and aortic wall reconstructed from a patient who underwent traumatic thoracic aortic injury repair. Mechanical properties of a Gore TAG thoracic endoprosthesis (W. L. Gore and Assoc, Flagstaff, Ariz) were assessed via experimen…
Cusp overlap technique for transcatheter self-expanding aortic valve implantation
2021
Transcatheter aortic valve implantation (TAVI) may cause atrioventricular conduction disturbances and, consequently, the necessity for permanent pacemaker implantation (PPI). This is because the His bundle surfaces at the basal part of the membranous septum (in the neighbourhood of the non-coronary cusp) and implant depth greater than the length of the membranous septum may interfere with the conduction system [1]. To mitigate this risk, the valve should be implanted at a high position to minimize the contact of the valve frame with the base of membranous septum. During TAVI, the valve is usually positioned in a coplanar fluoroscopic projection with 3 cusps view, but for a self-expanding va…
Lensless object scanning holography for two-dimensional mirror-like and diffuse reflective objects
2013
Recently proposed lensless object scanning holography (LOSH) [Opt. Express 20, 9382 (2012)] is a fully lensless method capable of improving the image quality in digital Fourier holography applied to one-dimensional (1D) reflective objects and it involves a very simplified experimental setup. LOSH is based on the recording and digital postprocessing of a set of digital lensless Fourier transform holograms, which finally results in a synthetic image with improved resolution, field-of-view (FOV), signal-to-noise ratio (SNR), and depth of field. In this paper, LOSH is extended to the cases of two-dimensional (2D) mirror-like and 1D diffuse-based objects. For 2D mirror-like objects, the experime…
Remote sensing of solar-induced chlorophyll fluorescence: Review of methods and applications
2009
Interest in remote sensing (RS) of solar-induced chlorophyll fluorescence (F) by terrestrial vegetation is motivated by the link of F to photosynthetic efficiency which could be exploited for large scale monitoring of plant status and functioning. Today, passive RS of F is feasible with different prototypes and commercial ground-based, airborne, and even spaceborne instruments under certain conditions. This interest is generating an increasing number of research projects linking F and RS, such as the development of new F remote retrieval techniques, the understanding of the link between the F signal and vegetation physiology and the feasibility of a satellite mission specifically designed f…
A class of shear deformable isotropic elastic plates with parametrically variable warping shapes
2017
A homogeneous shear deformable isotropic elastic plate model is addressed in which the normal transverse fibers are allowed to rotate and to warp in a physically consistent manner specified by a fixed value of a real non-negative warping parameter ω. On letting ω vary continuously (at fixed load and boundary conditions), a continuous family of shear deformable plates Pω is generated, which spans from the Kirchhoff plate at the lower limit ω=0, to the Mindlin plate at the upper limit ω=∞; for ω=2, Pω identifies with the third-order Reddy plate. The boundary-value problem for the generic plate Pω is addressed in the case of quasi-static loads, for which a principle of minimum total potential …