498 research outputs found

    Aplicaciones de la ingeniería ontológica a la gestión y análisis de la información geográfica

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    El estado del arte de la estructuración semántica de la Información Geográfica (IG), es decir, los nombres, códigos y atributos asociados a la geometría, es todavía, en cierta medida, pobre y rudimentario en la mayoría de los sistemas informáticos que la gestionan, ya sean Sistemas de Información Geográfica (SIG) o Infraestructuras de Datos Espaciales (IDE). Las nuevas posibilidades técnicas, dentro de las llamadas Tecnologías de la Información y las Comunicaciones, traídas de la mano por el fenómeno de la globalización (Web Semántica, Ingeniería Ontológica, Ingeniería del Conocimiento, gestión de taxonomías, modelado orientado a objetos, etc.) no han sido todavía suficientemente aplicadas al campo de la IG. Especial interés despierta la utilización de ontologías, como técnica para conseguir sistemas de análisis más inteligentes, de mayor potencia y eficacia, basados en modelos que recogen no sólo objetos, atributos y relaciones, sino además reglas de comportamiento, mecanismos de herencia, procedimientos y funciones que permiten la gestión de la información desde un nivel de significado mayor. Por todo ello, en el mundo de la IG, y en cuanto a lo que es la gestión de la semántica, se presentan como la evolución natural de los catálogos de fenómenos, listas de códigos y tesauros utilizados hasta ahora. En esta comunicación se describen los métodos más frecuentemente utilizados en la actualidad para organizar la componente semántica de la IG, se hace una introducción a los conceptos básicos relacionados con las ontologías y a las posibilidades que ofrecen. A continuación, se presenta una visión panorámica del estado de esta técnica, describiendo las soluciones software existentes y las líneas de actuación futura que se vislumbran. Todo ello, con el objetivo de definir modelos de explotación más inteligentes que manejen información geográfica en lugar de meros datos

    Web Semántica e Información Geográfica: Una interrelación necesaria ante las problemáticas actuales

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    Internet nos pone al alcance una cantidad ingente de documentación de cualquier tipo, sobre cualquier tema y en cualquier formato, consecuencia de que la Web actual constituye el mayor almacén de información recopilado por personas. Resultado de este gran volumen de información y de su crecimiento constante surgen diversos problemas que repercuten en la obtención de resultados. Con el objetivo de solventar la problemática actual e incrementar las potencialidades de las Web surge la Web Semántica, cuyo principal instrumento para la mejora de la organización y gestión de la información son las ontologías. La unión entre ontologías e información geográfica se presenta como la alternativa necesaria para poder solventar los principales problemas que atañen a esta información

    An approach towards a harmonized framework for hydrographic features domain

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    We describe an ontology in the hydrographic domain, hydrOntology, which can be used to overcome the semantic heterogeneity of different databases and other information sources that deal with geographic information. We show that ontologies are richer than other means commonly used to represent geographic information, such as feature catalogues and thesauri, and how ontologies could be used to overcome some of the problems associated with them

    Ten Years of Experience Training Non-Physician Anesthesia Providers in Haiti.

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    Surgery is increasingly recognized as an effective means of treating a proportion of the global burden of disease, especially in resource-limited countries. Often non-physicians, such as nurses, provide the majority of anesthesia; however, their training and formal supervision is often of low priority or even non-existent. To increase the number of safe anesthesia providers in Haiti, Médecins Sans Frontières has trained nurse anesthetists (NAs) for over 10 years. This article describes the challenges, outcomes, and future directions of this training program. From 1998 to 2008, 24 students graduated. Nineteen (79%) continue to work as NAs in Haiti and 5 (21%) have emigrated. In 2008, NAs were critical in providing anesthesia during a post-hurricane emergency where they performed 330 procedures. Mortality was 0.3% and not associated with lack of anesthesiologist supervision. The completion rate of this training program was high and the majority of graduates continue to work as nurse anesthetists in Haiti. Successful training requires a setting with a sufficient volume and diversity of operations, appropriate anesthesia equipment, a structured and comprehensive training program, and recognition of the training program by the national ministry of health and relevant professional bodies. Preliminary outcomes support findings elsewhere that NAs can be a safe and effective alternative where anesthesiologists are scarce. Training non-physician anesthetists is a feasible and important way to scale up surgical services resource limited settings

    Rationale, design and methodology for Intraventricular Pressure Gradients Study: a novel approach for ventricular filling assessment in normal and falling hearts

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    <p>Abstract</p> <p>Background</p> <p>Intraventricular pressure gradients have been described between the base and the apex of the left ventricle during early diastolic ventricular filling, as well as, their increase after systolic and diastolic function improvement. Although, systolic gradients have also been observed, data are lacking on their magnitude and modulation during cardiac dysfunction. Furthermore, we know that segmental dysfunction interferes with the normal sequence of regional contraction and might be expected to alter the physiological intraventricular pressure gradients. The study hypothesis is that systolic and diastolic gradients, a marker of normal left ventricular function, may be related to physiological asynchrony between basal and apical myocardial segments and they can be attenuated, lost entirely, or even reversed when ventricular filling/emptying is impaired by regional acute ischemia or severe aortic stenosis.</p> <p>Methods/Design</p> <p><it>Animal Studies: </it>Six rabbits will be completely instrumented to measuring apex to outflow-tract pressure gradient and apical and basal myocardial segments lengthening changes at basal, afterloaded and ischemic conditions. Afterload increase will be performed by abruptly narrowing or occluding the ascending aorta during the diastole and myocardial ischemia will be induced by left coronary artery ligation, after the first diagonal branch.</p> <p><it>Patient Studies: </it>Patients between 65-80 years old (n = 12), both genders, with severe aortic stenosis referred for aortic valve replacement will be selected as eligible subjects. A high-fidelity pressure-volume catheter will be positioned through the ascending aorta across the aortic valve to measure apical and outflow-tract pressure before and after aortic valve replacement with a bioprosthesis. Peak and average intraventricular pressure gradients will be recorded as apical minus outflow-tract pressure and calculated during all diastolic and systolic phases of cardiac cycle.</p> <p>Discussion</p> <p>We expect to validate the application of our method to obtain intraventricular pressure gradients in animals and patients and to promote a methodology to better understand the ventricular relaxation and filling and their correlation with systolic function.</p

    Arachnoid cyst in a patient with psychosis: Case report

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    <p>Abstract</p> <p>Background</p> <p>The aetiology of a psychotic disturbance can be due to a functional or organic condition. Organic aetiologies are diverse and encompass organ failures, infections, nutritional deficiencies and space-occupying lesions. Arachnoid cysts are rare, benign space-occupying lesions formed by an arachnoid membrane containing cerebrospinal fluid (CSF). In most cases they are diagnosed by accident. Until recently, the coexistence of arachnoid cysts with psychiatric disturbances had not been closely covered in the literature. However, the appearance of some references that focus on a possible link between arachnoid cysts and psychotic symptoms has increased the interest in this subject and raised questions about the etiopathogeny and the therapeutic approach involved.</p> <p>Clinical presentation</p> <p>We present the clinical report of a 21-year-old man, characterised by the insidious development of psychotic symptoms of varying intensity, delusional ideas with hypochondriac content, complex auditory/verbal hallucinations in the second and third persons, and aggressive behaviour. The neuroimaging studies revealed a voluminous arachnoid cyst at the level of the left sylvian fissure, with a marked mass effect on the left temporal and frontal lobes and the left lateral ventricle, as well as evidence of hypoplasia of the left temporal lobe. Despite the symptoms and the size of the cyst, the neurosurgical department opted against surgical intervention. The patient began antipsychotic therapy and was discharged having shown improvement (behavioural component), but without a complete remission of the psychotic symptoms.</p> <p>Conclusion</p> <p>It is difficult to be absolutely certain whether the lesion had influence on the patient's psychiatric symptoms or not.</p> <p>However, given the anatomical and neuropsychological changes, one cannot exclude the possibility that the lesion played a significant role in this psychiatric presentation. This raises substantial problems when it comes to choosing a therapeutic strategy.</p

    Use of Combined Hartree-Fock-Roothaan Theory in Evaluation of Lowest States of K [Ar]4s^0 3d^1 and Cr+ [Ar]4s^0 3d^5 Isoelectronic Series Over Noninteger n-Slater Type Orbitals

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    By the use of integer and noninteger n-Slater Type Orbitals in combined Hartree-Fock-Roothaan method, self consistent field calculations of orbital and lowest states energies have been performed for the isoelectronic series of open shell systems K [Ar]4s^0 3d^1 2(D) (Z=19-30) and Cr+ [Ar] 4s^0 3d^5 6(S) (Z=24-30). The results of calculations for the orbital and total energies obtained from the use of minimal basis sets of integer- and noninteger n-Slater Type Orbitals are given in tables. The results are compared with the extended-basis Hartree-Fock computations. The orbital and total energies are in good agreement with those presented in the literature. The results are accurately and considerably can be useful in the application of non-relativistic and relativistic combined Hartree-Fock-Roothaan approach for heavy atomic systems.Comment: 11 pages, 6 tables, 2 figures. submitte

    Morphological variation in a secondary contact between divergent lineages of brown trout (Salmo trutta) from the Iberian Peninsula

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    The aim of this study was to analyze the morphological variation of brown trout (Salmo trutta) in the Duero basin, an Atlantic river basin in the Iberian Peninsula, where a spatial segregation of two divergent lineages was previously reported, based on isozyme, microsatellite and mtDNA data. In these studies, two divergent pure regions (Pisuerga and Lower-course) and several hybrid populations between them were identified. Morphological variation was evaluated in 11 populations representative of the genetic differentiation previously observed in the Duero basin, using multivariate analysis on 12 morphometric and 4 meristic traits. A large differentiation between populations was observed (interpopulation component of variance: 41.8%), similar to that previously detected with allozymes and microsatellites. Morphometric differentiation was also reflected by the high classification success of pure and hybrid individuals to their respective populations, using multivariate discriminant functions (94.1% and 79.0%, respectively). All multivariate and clustering analyses performed demonstrated a strong differentiation between the pure regions. The hybrid populations, though showing large differentiation among them, evidenced an intermediate position between the pure samples. Head and body shape traits were the most discriminant among the morphometric characters, while pectoral rays and gillrakers were the most discriminant among the meristic traits. These results confirmed the high divergence of the brown trout from the Duero basin and suggest some traits on which selection could be acting to explain the spatial segregation observed
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