19 research outputs found

    Atrial fibrillation subtypes classification using the General Fourier-family Transform

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    Atrial fibrillation patients can be classified into paroxysmal, persistent and permanent attending to the temporal pattern of this arrhythmia. The surface electrocardiogram hides this differentiation. A classification method to discriminate between the different subtypes of atrial fibrillation by using short segments of electrocardiograms recordings is presented. We will process the electrocardiograms (ECGs) using time-frequency techniques with a global accuracy of 80%. Real cases are evaluated showing promising results for an implementation in a semiautomated diagnostic system.This work was supported by grants MTM2010-15200, PrometeoII/2013/013 and UPV-IIS La Fe, 2012/0468.Ortigosa, N.; Cano, O.; Ayala Gallego, G.; Galbis Verdu, A.; Fernandez Rosell, C. (2014). Atrial fibrillation subtypes classification using the General Fourier-family Transform. Medical Engineering and Physics. 36(4):554-560. https://doi.org/10.1016/j.medengphy.2013.12.005S55456036

    Lo glocal y el turismo. Nuevos paradigmas de interpretación.

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    El estudio del turismo se realiza desde múltiples escalas y enfoques, este libro aborda muchos temas que es necesario discutir desde diversas perspectivas; es el caso de la reflexión sobre la propia disciplina y sus conceptos, así como los asuntos específicos referidos al impacto territorial, los tipos de turismo, las cuestiones ambientales, el tema de la pobreza, la competitividad, las políticas públicas, el papel de las universidades, las áreas naturales protegidas, la sustentabilidad, la cultura, el desarrollo, la seguridad, todos temas centrales documentados y expuestos con originalidad y dominio del asunto. Lo multiescalar es básico para la comprensión del sistema turístico, sistema formado de procesos globales, regionales y locales. El eje de discusión del libro es lo glocal, esa interacción entre lo nacional y local con lo global

    Analysis of conservation priorities of Iberoamerican cattle based on autosomal microsatellite markers

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    Articles in International JournalsBackground: Determining the value of livestock breeds is essential to define conservation priorities, manage genetic diversity and allocate funds. Within- and between-breed genetic diversity need to be assessed to preserve the highest intra-specific variability. Information on genetic diversity and risk status is still lacking for many Creole cattle breeds from the Americas, despite their distinct evolutionary trajectories and adaptation to extreme environmental conditions. Methods: A comprehensive genetic analysis of 67 Iberoamerican cattle breeds was carried out with 19 FAOrecommended microsatellites to assess conservation priorities. Contributions to global diversity were investigated using alternative methods, with different weights given to the within- and between-breed components of genetic diversity. Information on Iberoamerican plus 15 worldwide cattle breeds was used to investigate the contribution of geographical breed groups to global genetic diversity. Results: Overall, Creole cattle breeds showed a high level of genetic diversity with the highest level found in breeds admixed with zebu cattle, which were clearly differentiated from all other breeds. Within-breed kinships revealed seven highly inbred Creole breeds for which measures are needed to avoid further genetic erosion. However, if contribution to heterozygosity was the only criterion considered, some of these breeds had the lowest priority for conservation decisions. The Weitzman approach prioritized highly differentiated breeds, such as Guabalá, Romosinuano, Cr. Patagonico, Siboney and Caracú, while kinship-based methods prioritized mainly zebu-related breeds. With the combined approaches, breed ranking depended on the weights given to the within- and between-breed components of diversity. Overall, the Creole groups of breeds were generally assigned a higher priority for conservation than the European groups of breeds. Conclusions: Conservation priorities differed significantly according to the weight given to within- and betweenbreed genetic diversity. Thus, when establishing conservation programs, it is necessary to also take into account other features. Creole cattle and local isolated breeds retain a high level of genetic diversity. The development of sustainable breeding and crossbreeding programs for Creole breeds, and the added value resulting from their products should be taken into consideration to ensure their long-term survival

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

    Sensitivity analysis of optimized curve fitting to uniform-noise point samples

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    Curve reconstruction from noisy point samples is needed for surface reconstruction in many applications (e.g. medical imaging, reverse engineering,etc.) -- Because of the sampling noise, curve reconstruction is conducted by minimizing the fitting error (f), for several degrees of continuity (usually C0, C1 and C2) -- Previous works involving smooth curves lack the formal assessment of the effect on optimized curve reconstruction of several inputs such as number of control points (m), degree of the parametric curve (p), composition of the knot vector (U), and degree of the norm (k) to calculate the penalty function (f) -- In response to these voids, this article presents a sensitivity analysis of the effect of mand k on f -- We found that the geometric goodness of the fitting (f) is much more sensitive to m than to k -- Likewise, the topological faithfulness on the curve fit is strongly dependent on m -- When an exaggerate number of control points is used, the resulting curve presents spurious loops, curls and peaks, not present in the input data -- We introduce in this article the spectral (frequency) analysis of the derivative of the curve fit as a means to reject fitted curves with spurious curls and peaks -- Large spikes in the derivative signal resemble Kronecker or Dirac Delta functions, which flatten the frequency content adinfinitum -- Ongoing work includes the assessment of the effect of curve degree p on f for non-Nyquist point sample

    Unidad logística de recuperación de residuos de construcción y demolición: estudio de caso Bogotá D.C.

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    One of the problems of the urban centers is the generation of "waste in the construction, demolition, rehabilitation and refurbishment - RCD"; which worsens by management and given control to the correct final disposal In addition, by the little potential use of reinstatement in the productive chains, generating impacts socio-environmental and economic; specific case of the city of Bogotá D.C. After the quantification, characterization and analysis of the waste generated In Situ, in the area of influence, supported trends and tools such as the design of production systems and the application in engineering of the eco-efficiency concept, obtained a diagnosis, through research, that allowed to structure the proposal of a recycling process and the identification of basic operational resources; In addition to the estimation and projection of the necessary technologies. Proposed potential quantities of materials logistics was formulated to manage, with parameters to international and national regulations, generating a distribution in pilot plant that complies with measures of design of the work units needed for the future management unit. In general, with the management model, provisions was attended the “Plan de Ordenamiento Territorial - POT“ with respect to its location and social, in-depth reason in the eco-efficient, in conjunction with the logistics system, has raised the question of research, which identified the resources essential for a future "logistic unit of pilot recycling of RCD to Bogotá D.C.".Uno de los problemas de los centros urbanos es la generación de “Residuos en la construcción, demolición, rehabilitación y remodelación – RCD” el cual empeora por la gestión y control dada para la correcta disposición final de éstos; además, por el poco uso potencial de reincorporación en las cadenas productivas, generando impactos socio-ambientales y económicos; caso específico de la ciudad de Bogotá D.C. Luego de la cuantificación, caracterización y análisis de los residuos generados In Situ, en el área de influencia, apoyados de tendencias y herramientas como el diseño de sistemas productivos y el concepto de aplicación en ingeniería de la ecoeficiencia, se obtuvo un diagnóstico, a través de la investigación, que permitió estructurar la proposición de un proceso de reciclaje y la identificación de recursos básicos de funcionamiento; además de la estimación y proyección de las tecnologías necesarias. Se formuló una propuesta logística con cantidades potenciales de los materiales a gestionar, con parámetros a nivel internacional y normatividad nacional, generando una distribución en planta piloto que cumple con las medidas de diseño de las unidades de trabajo necesarias para la futura Unidad de manejo. En general, con el modelo de gestión, se atendió lo estipulado en el Plan de Ordenamiento Territorial – POT, respecto a su ubicación y razón social, profundizado en la ecoeficiente, en conjunto con el sistema logístico, se planteó la pregunta de investigación, que identificó los recursos esenciales para una futura “Unidad Logística de Reciclaje Piloto de RCD para Bogotá D.C.”.

    A new evaluation framework and image dataset for keypoint extraction and feature descriptor matching

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    Key point extraction and description mechanisms play a crucial role in image matching, where several image points must be accurately identified to robustly estimate a transformation or to recognize an object or a scene -- New procedures for keypoint extraction and for feature description are continuously emerging -- In order to assess them accurately, normalized data and evaluation protocols are required -- In response to these needs, we present a (1) new evaluation framework that allow assessing the performance of the state-of-the-art feature point extraction and description mechanisms, (2) a new image dataset acquired under controlled affine and photometric transformations and (3) a testing image generator -- Our evaluation framework allows generating detailed curves about the performance of different approaches, providing a valuable insight about their behavior -- Also, it can be easily integrated in many research and development environments -- The contributions mentioned above are available on-line for the use of the scientific communit

    Robotic research platform for image-guided surgery assistance

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    In the context of surgery, it is very common to face challenging scenarios during the preoperative plan implementation -- The surgical technique’s complexity, the human anatomical variability and the occurrence of unexpected situations generate issues for the intervention’s goals achievement -- To support the surgeon, robotic systems are being integrated to the operating room -- However, current commercial solutions are specialized for a particular technique or medical application, being difficult to integrate with other systems -- Thus, versatile and modular systems are needed to conduct several procedures and to help solving the problems that surgeons face -- This article aims to describe the implementation of a robotic research platform prototype that allows novel applications in the field of imageguided surgery -- In particular, this research is focused on the topics of medical image acquisition during surgery, patient registration and surgical/medical equipment operation -- In this paper, we address the implementation of the general purpose teleoperation and path following modes of the platform, which constitute the base of future developments -- Also, we discuss relevant aspects of the system, as well as future directions and application fields to investigateIEEE Engineering in Medicine and Biology Societ

    Robust CT to US 3D-3D Registration by Using Principal Component Analysis and Kalman Filtering

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    Algorithms based on the unscented Kalman filter (UKF) have been proposed as an alternative for registration of point clouds obtained from vertebral ultrasound (US) and computerised tomography (CT) scans, effectively handling the US limited depth and low signaltonoise ratio -- Previously proposed methods are accurate, but their convergence rate is considerably reduced with initial misalignments of the datasets greater than or 30 mm -- We propose a novel method which increases robustness by adding a coarse alignment of the datasets’ principal components and batchbased point inclusions for the UKF -- Experiments with simulated scans with full coverage of a single vertebra show the method’s capability and accuracy to correct misalignments as large as and 90 mm -- Furthermore, the method registers datasets with varying degrees of missing data and datasets with outlier points coming from adjacent vertebraepp.52 - 6
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