Improving pan-European hydrological simulation of extreme events through statistical bias correction of RCM-driven climate simulations

In this work we asses the benefits of removing bias in climate forcing data used for hydrological climate change impact assessment at pan-European scale, with emphasis on floods. Climate simulations from the HIRHAM5-ECHAM5 model driven by the SRES-A1B emission scenario are corrected for bias using a histogram equalization method. As target for the bias correction we employ gridded interpolated observations of precipitation, average, minimum, and maximum temperature from the E-OBS data set. Bias removal transfer functions are derived for the control period 1961–1990. These are subsequently used to correct the climate simulations for the control period, and, under the assumption of a stationary error model, for the future time window 2071–2100. Validation against E-OBS climatology in the control period shows that the correction method performs successfully in removing bias in average and extreme statistics relevant for flood simulation over the majority of the European domain in all seasons. This translates into considerably improved simulations with the hydrological model of observed average and extreme river discharges at a majority of 554 validation river stations across Europe. Probabilities of extreme events derived employing extreme value techniques are also more closely reproduced. Results indicate that projections of future flood hazard in Europe based on uncorrected climate simulations, both in terms of their magnitude and recurrence interval, are likely subject to large errors. Notwithstanding the inherent limitations of the large-scale approach used herein, this study strongly advocates the removal of bias in climate simulations prior to their use in hydrological impact assessment

Chronic Cerebrospinal Venous Insufficiency (CCSVI) IN Meniere Disease. Case or Cause?

Abstract CCSVI is the acronym for Chronic Cerebrospinal Venous Insufficiency, initially described by P.Zamboni, as being strongly associated with multiple sclerosis (MS). It is a syndrome characterized by stenosis of the internal jugular veins (IJVs) and/or azygous vein (AZ) with opening of collaterals and insufficient drainage. Bavera PM carried out 823 Duplex exams on a control group of 60 patients without MS. As expected CCSVI was found only in few subjects of the control group, three, two females and one male, but all affected with Sudden Sensorineural Hearing Loss (SSHL). Successively, we reported a case of bilateral SSHL with vertigo, showing evidence of the CCSVI pattern at Duplex examination (not associated with MS). To the best of the authors' knowledge, this kind of association has never been reported. We studied 52 patients affected with cochleo-vestibular disturbances subdivided into two groups of out-patients:Definite unilateral Meniere (Men): 12 subjects (8 males and 4.females, mean age 41,6.yy) according to international AOO-HNS 1995 diagnostic criteria -No-Meniere (No-Men): 14 subjects (6.males and 8 females, mean age 44,7.yy) affected with unilateral cocleo-vestibular impairment A third group of subjects have been considered, as a "normal" group, 13 patients (8 females and 5 males, mean age 45,5 yy) affected with Benign Paroxismal Positioning Vertigo (BPPV) with cochlear involvement Asymmetrical artherious flow in VA or CA was revealed in 2 Men 9 no-Men and 1 BPPV, respectively 12,5 -60,7 -and 8,6 %. Differences between Men and NoMen and between each of this group with respect to BPPV were highly significant (p<0.001). Asymmetrical venous flow in IJV or VV was detected in 9 patients in MEN group and in 4 in no-MEN and 2 BPPV, respectively 79 -28,5 and 13 %. Differences between Men and No-Men and between each of this group with respect to BBV were highly significant (p<0.001

JTLex un generador de analizadores léxicos traductores

En el presente trabajo se exponen los puntos principales del diseño e implementación de JTLex, un generador de analizadores léxicos. JTLex, al contrario de los generadores existentes, permite la especificación conjunta de la sintaxis y la semántica de los componentes léxicos, siguiendo el estilo de los esquemas de traducción. Para ello se basa en un nuevo formalismo, las Expresiones Regulares Traductoras, introducido por los autores. Tanto su diseño como la especificación de los procedimientos con que el usuario implementa la semántica asociada a los símbolos son Orientados a Objetos. El lenguaje de implementación de JTLex es Java, como así también, el del código que genera y el que usa el usuario para definir la semántica. JTLex se integra, como un generador de analizadores léxicos alternativo al tradicional, a japlage; un entorno de generación de procesadores de lenguajes – en particular de compiladores -, desarrollado en el grupo, que permite la evaluación concurrente de cualquier Gramática de Atributos Bien Formada. Los lenguajes de especificación brindados por JTLex y por el generador de analizadores sintácticos de japlage siguen el estilo de Lex y Yacc respectivamente – que son prácticamente un estándar.Eje: Sistemas inteligentesRed de Universidades con Carreras en Informática (RedUNCI

JTLex un generador de analizadores léxicos traductores

En el presente trabajo se exponen los puntos principales del diseño e implementación de JTLex, un generador de analizadores léxicos. JTLex, al contrario de los generadores existentes, permite la especificación conjunta de la sintaxis y la semántica de los componentes léxicos, siguiendo el estilo de los esquemas de traducción. Para ello se basa en un nuevo formalismo, las Expresiones Regulares Traductoras, introducido por los autores. Tanto su diseño como la especificación de los procedimientos con que el usuario implementa la semántica asociada a los símbolos son Orientados a Objetos. El lenguaje de implementación de JTLex es Java, como así también, el del código que genera y el que usa el usuario para definir la semántica. JTLex se integra, como un generador de analizadores léxicos alternativo al tradicional, a japlage; un entorno de generación de procesadores de lenguajes – en particular de compiladores -, desarrollado en el grupo, que permite la evaluación concurrente de cualquier Gramática de Atributos Bien Formada. Los lenguajes de especificación brindados por JTLex y por el generador de analizadores sintácticos de japlage siguen el estilo de Lex y Yacc respectivamente – que son prácticamente un estándar.Eje: Sistemas inteligentesRed de Universidades con Carreras en Informática (RedUNCI

Bilateral sudden sensorineural hearing loss and chronic venous cerebrospinal insufficiency : a case report

OBJECTIVES: We report a case of bilateral sudden sensorineural hearing loss (SSHL) in a patient suffering from chronic venous cerebrospinal insufficiency (CCSVI). METHODS: Audiometric testing confirmed bilateral sensorineural hearing loss with hypoexcitability to caloric stimulation on the left side and echo-colour Doppler examination showed abnormal cerebral venous deficiency. RESULTS: The patient's condition improved after 15 days following medical treatment. CONCLUSIONS: CCSVI may explain the anatomical background which provides a predisposing factor for SSHL although further studies are needed to verify whether this observation is casual or coincidental

Avances en procesadores de lenguajes y proof-carrying code

En este trabajo se presentan las líneas del grupo de investigación “Procesadores de Lenguajes” perteneciente al Departamento de Computación de la UNRC. Los aspectos fundamentales son la creación de modelos y herramientas de última generación para la generación de procesadores de lenguajes incluyendo la generación de Código Móvil Seguro. Se reseñan los trabajos del último año que han permitido: construir un generador de analizadores léxicos traductores, construir un generador de evaluadores concurrentes sin comunicación de gramáticas de atributos, realizar un análisis comparativo de los generadores de procesadores de lenguajes más usados y de Japlage y definir un lenguaje assembler tipado para la ejecución segura de código móvil no confiable. Además, se presentan los trabajos iniciados por el grupo destacando la obtención de un prototipo de un compilador certificante y entorno de ejecución para Proof-Carrying Code (PCC) –una técnica para garantizar código móvil seguro-.Eje: Teoría de la ComputaciónRed de Universidades con Carreras en Informática (RedUNCI

Avances en procesadores de lenguajes y proof-carrying code

En este trabajo se presentan las líneas del grupo de investigación “Procesadores de Lenguajes” perteneciente al Departamento de Computación de la UNRC. Los aspectos fundamentales son la creación de modelos y herramientas de última generación para la generación de procesadores de lenguajes incluyendo la generación de Código Móvil Seguro. Se reseñan los trabajos del último año que han permitido: construir un generador de analizadores léxicos traductores, construir un generador de evaluadores concurrentes sin comunicación de gramáticas de atributos, realizar un análisis comparativo de los generadores de procesadores de lenguajes más usados y de Japlage y definir un lenguaje assembler tipado para la ejecución segura de código móvil no confiable. Además, se presentan los trabajos iniciados por el grupo destacando la obtención de un prototipo de un compilador certificante y entorno de ejecución para Proof-Carrying Code (PCC) –una técnica para garantizar código móvil seguro-.Eje: Teoría de la ComputaciónRed de Universidades con Carreras en Informática (RedUNCI

X-ray luminosity function of high-mass X-ray binaries: Studying the signatures of different physical processes using detailed binary evolution calculations

The ever-expanding observational sample of X-ray binaries (XRBs) makes them excellent laboratories for constraining binary evolution theory. Such constraints can be obtained by studying the effects of various physical assumptions on synthetic X-ray luminosity functions (XLFs) and comparing to observed XLFs. In this work, we focus on high-mass XRBs (HMXBs) and study the effects on the XLF of various, poorly-constrained assumptions regarding physical processes such as the common-envelope phase, the core-collapse, and wind-fed accretion. We use the new binary population synthesis code POSYDON, which employs extensive pre-computed grids of detailed stellar structure and binary evolution models, to simulate the evolution of binaries. We generate 96 synthetic XRB populations corresponding to different combinations of model assumptions. The generated HMXB XLFs are feature-rich, deviating from the commonly assumed single-power law. We find a break in our synthetic XLF at luminosity $\sim 10^{38}$ erg s$^{-1}$, similar to observed XLFs. However, we find also a general overabundance of XRBs (up to a factor of $\sim$10 for certain model parameter combinations) driven primarily by XRBs with black hole accretors. Assumptions about the transient behavior of Be-XRBs, asymmetric supernova kicks, and common-envelope physics can significantly affect the shape and normalization of our synthetic XLFs. We find that less well-studied assumptions regarding the circularization of the orbit at the onset of Roche-lobe overflow and criteria for the formation of an X-ray emitting accretion disk around wind-accreting black holes can also impact our synthetic XLFs. Our study reveals the importance of large-scale parameter studies, highlighting the power of XRBs in constraining binary evolution theory.Comment: 31 pages, 32 figures, Accepted by A&A. Fixed typos and updated references. Referee's comments were addresse

Revisiting the explodability of single massive star progenitors of stripped-envelope supernovae

Stripped-envelope supernovae (Types IIb, Ib, and Ic) that show little or no hydrogen comprise roughly one-third of the observed explosions of massive stars. Their origin and the evolution of their progenitors are not yet fully understood. Very massive single stars stripped by their own winds ($\gtrsim 25-30 M_{\odot}$ at solar metallicity) are considered viable progenitors of these events. However, recent 1D core-collapse simulations show that some massive stars may collapse directly into black holes after a failed explosion, with a weak or no visible transient. In this letter, we estimate the effect of direct collapse into a black hole on the rates of stripped-envelope supernovae that arise from single stars. For this, we compute single-star MESA models at solar metallicity and map their final state to their core-collapse outcome following prescriptions commonly used in population synthesis. According to our models, no single stars that have lost their entire hydrogen-rich envelope are able to explode, and only a fraction of progenitors left with a thin hydrogen envelope do (IIb progenitor candidates), unless we use a prescription that takes the effect of turbulence into account or invoke increased wind mass-loss rates. This result increases the existing tension between the single-star paradigm to explain most stripped-envelope supernovae and their observed rates and properties. At face value, our results point toward an even higher contribution of binary progenitors to stripped-envelope supernovae. Alternatively, they may suggest inconsistencies in the common practice of mapping different stellar models to core-collapse outcomes and/or higher overall mass loss in massive stars.Comment: Published in Astronomy & Astrophysics Letters; One main enhancement: added Couch et al. (2020) in the list of supernova engine

Bridging the gap between chronic cerebrospinal venous insufficiency and Ménière disease

M\ue9ni\ue8re disease (MD) is a chronic illness of the inner ear that affects a substantial number of patients every year worldwide. Because of a dearth of well-controlled studies, the medical and surgical management of MD remains quite empirical. The main reason is that it is very difficult to investigate patients affected with \u201cCertain MD\u201d due to the post-mortem criterion necessary for this diagnostic grade. The aim of this paper is an attempt to approach MD into the context of the more recent findings about the global brain waste clearance system, to which inner ear is anatomically and functionally connected, in order to build a reasonable model of MD pathogenesis. it seems nowadays reasonable to state that CCSVI may be the anatomical background to develop endolymphatic hydrops in MD, the worldwide accepted pathogenetic mechanism of the disease. The mechanism leading from CCSVI to MD is still debated. Since MD has been correlated mostly to a wide and different diseases and treatments, CCSVI may be considered more than a cause of MD per se, rather the anatomical predisposition to develop the disease. CCSVI may lead to endolymphatic hydrops through a pure \u201chydraulic\u201d mechanism but in the model proposed in this paper CCSVI interplays with the Glymphatic (GS) and Brain Lymphatic System (LS) and MD development is due to a failure of the congenital venous abnormalities: MD develops when vascular and/or glymphatic and/or lymphatic compensation fails