3,604 research outputs found

    Conflación semántica: Análisis de fenómenos en el contexto de los WFS

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    Este artículo pretende hacer un análisis crítico de los servicios de fenómenos (WFS), en concreto a su parte relativa a los fenómenos que contemplan estos servicios. Así, se repasará el estándar OGC para estos servicios y se analizará la accesibilidad a esta información, la lengua en la que se encuentran los nombres de los fenómenos y la descriptividad de estos nombres. Todo ello de cara a conseguir unos servicios verdaderamente útiles, de los que se pueda sacar el mayor beneficio posible tanto por otras aplicaciones como por otros usuarios. Este análisis se aplicará a un conjunto de servicios de libre acceso disponibles en la Web y para cada caso se irán viendo las características y su adecuación al estándar o a las recomendaciones clave para conseguir la mayor usabilidad de cara a la explotación

    Conflación semántica sobre Linked Data

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    Últimamente se está produciendo un gran apogeo en la publicación de información de muchas áreas temáticas en la Web de los Datos Enlazados (Linked Data). La información publicada en formato RDF tiene asociada un modelo conceptual (ontología) por el que se rige. El número de conjuntos de datos publicados y ontologías asociadas empieza a ser numeroso en distintas áreas, aunque las consultas de forma general han de realizarse de manera individualizada. En este artículo, mediante la conflación semántica, hemos desarrollado un enfoque y un sistema de consultas centralizadas que hace transparente para el usuario la diferente distribución de los datos en la nube que supone Linked Data

    Relacionando la información geográfica con su componente semántico a través de las IDE

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    La cantidad de datos enlazados (Linked Data) publicados en la Web de los Datos ha experimentado un enorme crecimiento en los últimos años. La información publicada en formato RDF tiene asociada un modelo conceptual (ontología) por el que se rige. Las consultas a los conjuntos de datos publicados se realizan, generalmente, de manera individualizada. En este artículo, mediante la conflación semántica, se desarrolla un enfoque y un sistema de consultas centralizadas que hace transparente para el usuario la diferente distribución de los datos en la nube que supone Linked Data. Los resultados obtenidos a través del sistema desarrollado se visualizan utilizando el WMS de la IDEE. En definitiva, el enfoque propuesto permite la integración de las Infraestructuras de Datos Espaciales y Linked Data

    The IGN-E case: Integrating through a hidden ontology

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    National Geographic Institute of Spain (IGN-E) wanted to integrate its main information sources for building a common vocabulary reference and thus to manage the huge amount of information it held. The main problem of this integration is the great heterogeneity of data sources. The Ontology Engineering Group (OEG) is working with IGN-E to attain this objective in two phases: first, by creating automatically an ontology using the semantics of catalogues sections, and second, by discovering mappings automatically that can relate ontology concepts to database instances. So, these mappings are the instruments to break the syntactic, semantic and granularity heterogeneity gap. We have developed software for building a first ontology version and for discovering automatically mappings using techniques that take into account all types of heterogeneity. The ontology contains a set of extra-attributes which are identified in the building process. The ontology, called PhenomenOntology, will be reviewed by domain experts of IGN-E. The automatic mapping discovery will be also used for discovering new knowledge that will be added to the ontology. For increasing the usability and giving independence to different parts, the processes of each phase will be designed automatically and as upgradeable as possible

    Hacia una armonización semántica de la Información Geográfica

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    La demanda de Información Geográfica (IG) se está convirtiendo en una necesidad de primer orden, consecuencia del potencial de los geodatos como instrumento para facilitar la toma de decisiones y la gestión de recursos en diversas áreas (catastro, recursos naturales, etc. ). Pero, consecuencia de la pobre estructuración y la heterogeneidad de vocabularios existentes, son muchos los problemas para conseguir búsquedas y recuperación de información exitosas, asegurar la continuidad entre informaciones semejantes de distintas fuentes, etc. Estos problemas surgen principalmente de una producción y uso de la cartografía tradicionalmente centrada en las necesidades específicas de cada cual, donde no era tan importante como ahora el disponer de modelos comunes de la realidad geográfica. Para satisfacer estas nuevas necesidades, las ontologías se pueden utilizar como un instrumento para definir los significados de los fenómenos y generar modelos coherentes de la realidad, proporcionando un entendimiento común y compartido que dará solución a estos problemas. La Ingeniería Ontológica está modificando muchos conceptos, ideas y estrategias aplicadas en los procesos de estructuración y gestión “clásica” de la IG

    Research on nonlinear and quantum optics at the photonics and quantum information group of the University of Valladolid

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    We outline the main research lines in Nonlinear and Quantum Optics of the Group of Photonics and Quantum Information at the University of Valladolid. These works focus on Optical Solitons, Quantum Information using Photonic Technologies and the development of new materials for Nonlinar Optics. The investigations on optical solitons cover both temporal solitons in dispersion managed fiber links and nonparaxial spatial solitons as described by the Nonlinear Helmholtz Equation. Within the Quantum Information research lines of the group, the studies address new photonic schemes for quantum computation and the multiplexing of quantum data. The investigations of the group are, to a large extent, based on intensive and parallel computations. Some associated numerical techniques for the development of the activities described are briefly sketched

    Utilidade do Strain Bidimensional por Speckle Tracking da Aurícula e Ventrículo Direito para Predizer Arritmias Tardias em Doentes Adultos com Tetralogia de Fallot Corrigida

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    OBJECTIVE: To determine whether right ventricular and/or atrial speckle tracking strain is associated with previous arrhythmic events in patients with repaired tetralogy of Fallot. METHODS AND RESULTS: We studied right ventricular and atrial strain in 100 consecutive patients with repaired tetralogy of Fallot referred for routine echocardiographic evaluation. Patients were divided into two groups, one with previous documentation of arrhythmias (n=26) and one without arrhythmias, in a median follow-up of 22 years. Patients with arrhythmias were older (p<0.001) and had surgical repair at an older age (p=0.001). They also had significantly reduced right ventricular strain (-14.7±5.5 vs. -16.9±4.0%, p=0.029) and right atrial strain (19.1±7.7% vs. 25.8±11.4%, p=0.001). Neither right ventricular nor right atrial strain were independent predictors of the presence of a history of documented arrhythmias, which was associated with age at correction and with the presence of residual defects. In a subanalysis after excluding 23 patients who had had more than one corrective surgery, right ventricular strain was an independent predictor of the presence of previous arrhythmic events (OR 1.19, 95% CI 1.02-1.38, p=0.025). Right atrial strain was also an independent predictor after adjustment (OR 0.93, 95% CI 0.87-0.99, p=0.029). The ideal cut-off for right ventricular strain was -15.3% and for right atrial strain 23.0%. CONCLUSIONS: Compared with conventional echocardiographic parameters, strain measures of the right heart are associated with the presence of arrhythmic events, and may be useful for risk stratification of patients with repaired tetralogy of Fallot, although a prospective study is required.info:eu-repo/semantics/publishedVersio

    Late-stage diagnosis of HIV infection in Brazilian children: evidence from two national cohort studies

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    This study analyzed data from two consecutive retrospective cohort samples (1983 to 1998 and 1999 to 2002) of Brazilian children with AIDS (N = 1,758) through mother-to-child-transmission. Late-stage diagnosis (CDC category C) was investigated in relation to the following variables: year of birth, year of HIV diagnosis, and time periods related to changes in government treatment guidelines. Late-stage diagnosis occurred in 731 (41.6%) of cases and was more prevalent in infants under 12 months of age. The rate of late-stage diagnosis decreased from 48% to 36% between the two periods studied. We also observed a reduction in the proportion of late-stage diagnoses and the time lapse between HIV diagnosis and ART initiation. A significant association was found between timely diagnosis and having been born in recent years (OR = 0.62; p = 0.009) and year of HIV diagnosis (OR = 0.72; p = 0.002/OR = 0.62; p < 0.001). Infants under the age of 12 months were more likely to be diagnosed at a late stage than older children (OR = 1.70; p = 0.004). Despite advances, there is a need to improve the effectiveness of policies and programs focused on improving early diagnosis and management of HIV/AIDS

    Cardiac Myxoma: a 13-Year Experience in Echocardiographic Diagnosis.

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    INTRODUCTION: Transthoracic echocardiography is the method of choice for the diagnosis of cardiac myxomas, but the transesophageal approach provides a better definition of the location and characteristics of the tumor. The authors review their thirteen years' experience on the echocardiographic diagnosis of this pathology. METHODS: From 1994 to 2007, 41 cardiac tumors were diagnosed in our echocardiographic laboratory, of which 27 (65.85%) were cardiac myxomas. The exams and the patients' clinical files were retrospectively reviewed. RESULTS: Of the 27 patients, 22 (81.5%) were female, with a mean age of 62.1 +/- 13.6 years (25-84 years). The predominant clinical features were due to the obstruction caused by the tumor in more than two thirds of the patients, followed by constitutional symptoms in one third and embolic events in 30%. In the lab results, anemia was found in three patients and elevated sedimentation rate and CRP in two. In two patients the myxoma was found by chance. All the cases were of the sporadic type, although we found a prevalence of thyroid disease of 14% (4 patients). All patients underwent urgent surgical resection except one, in whom surgery was refused due to advanced age and comorbidities. The myxomas followed a typical distribution with 24 (88.8%) located in the left atrium, 18 of them attached to the atrial septum (AS) and two to the mitral valve. In one patient, the tumor involved both atria. The other two cases originated in the right atrium at the AS. Embolic phenomena were more frequent in small tumors (p = 0.027) and in those with a villous appearance (p = 0.032). Obstructive manifestations were associated with larger tumors (p = 0.046) and larger left atria (p = 0.048). In our series, there were no deaths during hospitalization or in the follow-up period of 5.2 +/- 3.7 years in 19 patients. There were two recurrences, both patients being successfully reoperated. CONCLUSION: Myxoma is the most common cardiac tumor. Transesophageal echocardiography provides excellent morphologic definition, aiding in diagnosis and follow-up. Most clinical manifestations are obstructive and are associated with larger tumors. Small tumors with a friable appearance have a higher chance of embolization. Surgical resection is usually curative and the long-term prognosis is excellent

    Population-based rare variant detection via pooled exome or custom hybridization capture with or without individual indexing

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    BACKGROUND: Rare genetic variation in the human population is a major source of pathophysiological variability and has been implicated in a host of complex phenotypes and diseases. Finding disease-related genes harboring disparate functional rare variants requires sequencing of many individuals across many genomic regions and comparing against unaffected cohorts. However, despite persistent declines in sequencing costs, population-based rare variant detection across large genomic target regions remains cost prohibitive for most investigators. In addition, DNA samples are often precious and hybridization methods typically require large amounts of input DNA. Pooled sample DNA sequencing is a cost and time-efficient strategy for surveying populations of individuals for rare variants. We set out to 1) create a scalable, multiplexing method for custom capture with or without individual DNA indexing that was amenable to low amounts of input DNA and 2) expand the functionality of the SPLINTER algorithm for calling substitutions, insertions and deletions across either candidate genes or the entire exome by integrating the variant calling algorithm with the dynamic programming aligner, Novoalign. RESULTS: We report methodology for pooled hybridization capture with pre-enrichment, indexed multiplexing of up to 48 individuals or non-indexed pooled sequencing of up to 92 individuals with as little as 70 ng of DNA per person. Modified solid phase reversible immobilization bead purification strategies enable no sample transfers from sonication in 96-well plates through adapter ligation, resulting in 50% less library preparation reagent consumption. Custom Y-shaped adapters containing novel 7 base pair index sequences with a Hamming distance of ≥2 were directly ligated onto fragmented source DNA eliminating the need for PCR to incorporate indexes, and was followed by a custom blocking strategy using a single oligonucleotide regardless of index sequence. These results were obtained aligning raw reads against the entire genome using Novoalign followed by variant calling of non-indexed pools using SPLINTER or SAMtools for indexed samples. With these pipelines, we find sensitivity and specificity of 99.4% and 99.7% for pooled exome sequencing. Sensitivity, and to a lesser degree specificity, proved to be a function of coverage. For rare variants (≤2% minor allele frequency), we achieved sensitivity and specificity of ≥94.9% and ≥99.99% for custom capture of 2.5 Mb in multiplexed libraries of 22–48 individuals with only ≥5-fold coverage/chromosome, but these parameters improved to ≥98.7 and 100% with 20-fold coverage/chromosome. CONCLUSIONS: This highly scalable methodology enables accurate rare variant detection, with or without individual DNA sample indexing, while reducing the amount of required source DNA and total costs through less hybridization reagent consumption, multi-sample sonication in a standard PCR plate, multiplexed pre-enrichment pooling with a single hybridization and lesser sequencing coverage required to obtain high sensitivity
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