1,100 research outputs found

    Gigant Transethmoidal Meningoencephalocele Operated by Full Endonasal Endoscopic Approach: Case Report

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    Intranasal meningoencephaloceles have historically been managed by neurosurgeons, although their main clinical manifestations are rhinological. Recent advances in endoscopic skull base surgery has significantly improved the treatment of these lesions and consequently diminished appreciable surgical morbidity. We report an ethmoidal meningoencephalocele case operated on by endonasal endoscopic approach for removal of the lesion and reconstructing the associated skull base. From this experience, we conclude that removal of the lesion and watertight closure of the skull base irrespective of the size of the mass and anterior skull base defect are the operation's most important aspects

    Vasoreactivity in CADASIL: comparison to structural MRI and neuropsychology

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    Impaired cerebrovascular reactivity precedes histological and clinical evidence of CADASIL in animal models. We aimed to more fully characterise peripheral and cerebral vascular function and reactivity in a cohort of adult CADASIL patients, and explore the associations of these with conventional clinical, imaging and neuropsychological measures. 22 adults with CADASIL gave informed consent to participate in an exploratorystudy of vascular function in CADASIL. Clinical assessment, comprehensive vascular assessment, MRI and neuropsychological testing were conducted. Transcranial Doppler and arterial spin labelling MRI with hypercapnia challenge both measured cerebral vasoreactivity. Number and volume of lacunes, subcortical hyperintensity volume, microbleeds and normalised brain volume were assessed on MRI scans. Analysis was exploratory and examined associations between different markers. The results showed that cerebrovascular reactivity measured by ASL correlated with peripheral vasoreactivity measured by flow mediated dilatation. Subjects with >5 lacunes were older, with evidence of atherosclerosis and had impaired cerebral and peripheral vasoreactivity. Subjects with depressive symptoms, disability or delayed processing speed, also had impaired vasoreactivity, as well as more lacunes and brain atrophy. Impaired vasoreactivity and vascular dysfunction may play a significant role in the pathophysiology of CADASIL and vascular tests may be important to include in both longitudinal and clinical trials

    A ringed pole-on outflow from DO Tauri revealed by ALMA

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    We present new ALMA Band 6 observations including the CO (2-1) line and 1.3 mmcontinuum emission from the surroundings of the young stellar object DO Tauri. TheALMA CO molecular data show three different series of rings at different radial ve-locities. These rings have radii around 220 au and 800 au. We make individual fits tothe rings and note that their centers are aligned with DO Tauri and its optical high-velocity jet. In addition, we notice that the velocity of these structures increases withthe separation from the young star. We discuss the data under the hypothesis that therings represent velocity cuts through three outflowing shells that are possibly drivenby a wide-angle wind, dragging the environment material along a direction close to theline of sight (i= 19◦). We estimate the dynamical ages, the mass, the momentum andthe energy of each individual outflow shell and those of the whole outflow. The resultsare in agreement with those found in outflows from Class II sources. We make a roughestimate for the size of the jet/wind launching region, which needs to be of.15 au.We report the physical characteristics of DO Tauri?s disk continuum emission (almostface-on and with a projected major axis in the north-south direction) and its velocitygradient orientation (north-south), indicative of disk rotation for a 1-2 Mcentral star.Finally we show an HST [SII] image of the optical jet and report a measurement of itsorientation in the plane of the sky.Fil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Zapata Gonzalez, Luis Alberto. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: Rodríguez, Luis F.. Universidad Nacional Autonoma de Mexico. Instituto de Astronomia; MéxicoFil: Vazzano, María Mercedes. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Guzman, Andrés E.. National Astronomical Observatory Of Japan; JapónFil: López, Rosario. Universidad Autónoma de Barcelona. Facultad de Física. Departamento Astronomía y Meteorología; Españ

    La nueva teoría social en hispanoamérica. Introducción a la teoría de sistemas constructivista

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    El propósito de esta obra es responder al creciente interés en ciencias sociales por libros en lengua española sobre la Teoría de Sistemas Constructivista. Las tres preguntas que frecuentemente se hacen a esta teoría son: qué significan sus conceptos, cuál es su metodología y cómo se puede llevar a la práctica una investigación tal. Con respecto a la primera pregunta, es posible afirmar que hay mayor claridad en su respuesta que en las dos preguntas siguientes. Un investigador neófito no ocuparía la palabra claridad, pero debería reconocer que está disponible una mayor cantidad de bibliografía teórica sobre el asunto, que sobre sus variantes metodológicas o de aplicación en estudios. En nuestra experiencia académica, hay dos tipos de aprendices de la teoría de sistemas constructivista: aquellos que son instruidos por un profesor y aquellos que se aproximan de manera autodidacta. Quienes más sufren los rigores de la teoría son estos últimos, aunque los otros tienen el apoyo emocional de sus maestros cuando entran en la típica desesperación inicial. Lo anterior siempre nos ha llevado a pensar que la enseñanza universitaria es vital para lograr dar una respuesta con fundamentos, y atractiva, a las mencionadas tres preguntas frecuentes sobre la teoría de sistemas constructivista

    Stroke penumbra defined by an MRI-based oxygen challenge technique: 2. Validation based on the consequences of reperfusion

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    Magnetic resonance imaging (MRI) with oxygen challenge (T2* OC) uses oxygen as a metabolic biotracer to define penumbral tissue based on CMRO2 and oxygen extraction fraction. Penumbra displays a greater T2* signal change during OC than surrounding tissue. Since timely restoration of cerebral blood flow (CBF) should salvage penumbra, T2* OC was tested by examining the consequences of reperfusion on T2* OC-defined penumbra. Transient ischemia (109±20 minutes) was induced in male Sprague-Dawley rats (n=8). Penumbra was identified on T2*-weighted MRI during OC. Ischemia and ischemic injury were identified on CBF and apparent diffusion coefficient maps, respectively. Reperfusion was induced and scans repeated. T2 for final infarct and T2* OC were run on day 7. T2* signal increase to OC was 3.4% in contralateral cortex and caudate nucleus and was unaffected by reperfusion. In OC-defined penumbra, T2* signal increased by 8.4%±4.1% during ischemia and returned to 3.25%±0.8% following reperfusion. Ischemic core T2* signal increase was 0.39%±0.47% during ischemia and 0.84%±1.8% on reperfusion. Penumbral CBF increased from 41.94±13 to 116.5±25 mL per 100 g per minute on reperfusion. On day 7, OC-defined penumbra gave a normal OC response and was located outside the infarct. T2* OC-defined penumbra recovered when CBF was restored, providing further validation of the utility of T2* OC for acute stroke management

    Stroke penumbra defined by an MRI-based oxygen challenge technique: 1. validation using [14C]2-deoxyglucose autoradiography

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    Accurate identification of ischemic penumbra will improve stroke patient selection for reperfusion therapies and clinical trials. Current magnetic resonance imaging (MRI) techniques have limitations and lack validation. Oxygen challenge T2* MRI (T2* OC) uses oxygen as a biotracer to detect tissue metabolism, with penumbra displaying the greatest T2* signal change during OC. [14C]2-deoxyglucose (2-DG) autoradiography was combined with T2* OC to determine metabolic status of T2*-defined penumbra. Permanent middle cerebral artery occlusion was induced in anesthetized male Sprague-Dawley rats (n=6). Ischemic injury and perfusion deficit were determined by diffusion- and perfusion-weighted imaging, respectively. At 147±32 minutes after stroke, T2* signal change was measured during a 5-minute 100% OC, immediately followed by 125 μCi/kg 2-DG, intravenously. Magnetic resonance images were coregistered with the corresponding autoradiograms. Regions of interest were located within ischemic core, T2*-defined penumbra, equivalent contralateral structures, and a region of hyperglycolysis. A T2* signal increase of 9.22%±3.9% (mean±s.d.) was recorded in presumed penumbra, which displayed local cerebral glucose utilization values equivalent to contralateral cortex. T2* signal change was negligible in ischemic core, 3.2%±0.78% in contralateral regions, and 1.41%±0.62% in hyperglycolytic tissue, located outside OC-defined penumbra and within the diffusion abnormality. The results support the utility of OC-MRI to detect viable penumbral tissue follow

    Formación universitaria humanismo y conocimiento

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    El libro está integrado por seis capítulos, los cuales representan el fruto de la investigación que desarrolla el Cuerpo Académico: “Estudios de la Universidad”, adscrito al Instituto de Estudios sobre la Universidad (IESU), de la Universidad Autónoma del Estado de México. El propósito de los siguientes trabajos es abrir una serie de caminos que permitan pensar el ser y quehacer de la universidad en el siglo XXI. Los temas resaltan la necesidad e importancia de pensar la educación universitaria en pos de una formación que le dé sentido a la existencia humana.La función social de las universidades se ancla en la base de una formación del ser humano tanto en su ser como en la ciencia y el conocimiento. Formar significa construir desde sí mismo y para los otros la condición de la humanidad. La universidad en ese sentido tiene la tarea de promover en el universitario las condiciones para la formación de la persona, desde todo tipo de conocimientos y saberes. El propósito de los siguientes trabajos es abrir una serie de caminos que permitan pensar el ser y quehacer de la universidad en el siglo XXI. Los temas resaltan la necesidad e importancia de pensar la educación universitaria en pos de una formación que le dé sentido a la existencia humana.UAE

    Formación y vocación universitarias

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    El planteamiento central es que la formación univer-sitaria en las ciencias instrumentales debe ser un espacio que posibilite la armonización del conocimiento instru-mental, socioambiental y humanístico; así se rompería con la predominancia del conocimiento hiperespecializado, ya sea abriéndose a la complejidad, la interdisciplina o la transdisciplina; a la vez que, en el centro, estaría lo humano como integrante con responsabilidad de lo social y ambiental. Para ello González considera importante que el universitario se reconozca en su condición social, personal y contextual como ciudadano no limitado a la profesión que se cultiva, en un horizonte de acción en el presente para el futuro y en un contexto incierto, ante lo cual debe asumir su responsabilidad.Secretaría de Educación Pública-Subsecretaría de Educación Superior-Dirección General de Educación Superior Universitaria. Número del convenio con la SEP: 2018-15-001-017

    Time expansion in distributed optical fiber sensing

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    The work of MRFR and HFM was supported by the MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU»/PRTR under grants RYC2021-032167-I and RYC2021- 035009-I. The work of MSA and VD was supported by MCIN/AEI/10.13039/ 501100011033 and the FSE invierte en tu futuro under grants PRE-2019- 087444 and RYC-2017-23668, respectively.Distributed optical fiber sensing (DOFS) technology has recently experienced an impressive growth in various fields including security, structural monitoring and seismology, among others. This expansion has been accompanied by a speedy development of the technology in the last couple of decades, reaching remarkable performance in terms of sensitivity, range, number of independent sensing points and affordable cost per monitored point as compared with competing technologies such as electrical or point optical sensors. Phase-sensitive Optical Time-Domain Reflectometry (ϕOTDR) is a particularly interesting DOFS technique, since it enables real-time monitoring of dynamic variations of physical parameters over a large number of sensing points. Compared to their frequency-domain counterparts (OFDR), ϕOTDR sensors typically provide higher dynamics and longer ranges but significantly worse spatial resolutions. Very recently, a novel ϕOTDR approach has been introduced, which covers an existing gap between the long range and fast response of ϕOTDR and the high spatial resolution of OFDR. This technique, termed time-expanded (TE) ϕOTDR, exploits an interferometric scheme that employs two mutually coherent optical frequency combs. In TE-ϕOTDR, a probe comb is launched into the fiber under test. The beating of the backscattered light and a suitable LO comb produces a multi-heterodyne detection process that compresses the spectrum of the probe comb, in turn expanding the detected optical traces in the time-domain. This approach has allowed sensing using ϕOTDR technology with very high resolution (in the cm scale), while requiring outstandingly low detection and acquisition bandwidths (sub-MHz). In this work, we review the fundamentals of TE-ϕOTDR technology and describe the recent developments, focusing on the attainable sensing performance, the existing trade-offs and open working lines of this novel sensing approach.Comunidad de MadridMinisterio de Ciencia e InnovaciónAgencia Estatal de InvestigaciónGeneralitat ValencianaUniversitat Jaume IEuropean Commissio
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