18 research outputs found

    Array sísmico inalámbrico y de parámetros ambientales para la caracterización de precursores de actividad volcánica

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    The global seismic activity is extensively studied and well characterized by seismic networks focused on the seismic hazards derived from earthquakes. However, a specific study on volcano seismicity is not widespread, due to the wide variety of volcanic signals as well as the long periods of quiescence of many volcanoes. Seismic array technology emerged as a method for nuclear tests monitoring, however, it soon became an important tool for the analysis and location of volcano seismic signals thanks to a wide variety of processing techniques. From the techniques applied in array processing, in this PhD Thesis the beamforming algorithm has been chosen. In classical seismic arrays, the analog signals from each sensor are wired transmitted to the central acquisition system, resulting in a decrease of quality of the processed signal. Central node must perform signal acquisition from all sensors, establish a time control through the use of a GPS, store data and transmit them. Moreover, the volcanic monitoring equipment could be destroyed, or have depleted its power source, thus, it becomes evident the need of very low cost and high autonomy equipments, which currently do not exist. In this way, a seismic array has been designed, consisting of a wireless seismic network that allows any array topology, removing the need of any wire connection. It is a significant step forward over existing devices, due to involved cost reduction and autonomy obtained, that allow fast deployment without the need of large investments. These equipments present high versatility, thanks to the use of the latest technologies in both hardware and software, using an open source operating system with embedded Linux where all software is free. This allows us to configure and display recorded data on real time, through a webpage and an instant messaging application, in order to be able to track the activity at any moment and from everywhere. Array localization techniques are based on the search for the maximum coherence of the recorded signals by each sensor of the array, improving the quality of the seismic signal by coherently adding the signal of each element. This implies that the most important part in the data acquisition is to obtain the time delay of each signal accurately. Synthetic tests show that a delay in the synchronism of one millisecond implies an error of less than one degree in determining the arrival angle. In order to increase the accuracy of time synchronization, it has been experimented in the laboratory with the IEEE 1588 PTP standard, using Xbee PRO commercial wireless modules, achieving synchronization of the order of microseconds, well above the data analysis requirements. The final result of this Thesis has allowed the development of a compact seismic acquisition system with low-power consumption (515,24 mW), low cost (at least 10% below average commercial systems), low-noise (2-bit A/D 24) and lightweight, making easier the possibility to develop a significant number of these devices. The equipment has been checked in the laboratory through automated measurement systems and calibration procedures. It has been also tested in different field campaigns where wireless seismic array was compared to a wired array of the IGN (as a reference), both using the MARK L4 seismic sensor (vertical component, and 1second natural period), being the signal-to-noise ratio of both equipment identical. Taking into account the tolerance of the A/D clock of the different stations in the array, it has been verified that in the worst case the synchronization error was 650 µs.La actividad sísmica a nivel global está ampliamente estudiada y queda bien caracterizada mediante las redes de sismómetros enfocadas al riesgo sísmico derivado de los terremotos. Sin embargo, el estudio específico de la sismicidad volcánica está poco extendido, debido a la gran variedad de señales volcánicas y a los largos periodos de inactividad que pueden presentar los volcanes. A pesar de que la tecnología de arrays sísmicos (antenas sísmicas) surgió para la vigilancia de explosiones nucleares, pronto se convirtió en una herramienta de gran utilidad en el análisis y localización de señales volcánicas gracias a su gran variedad de técnicas de procesado. La diferencia principal entre un array y una red de sismómetros, se encuentra en las diversas técnicas de análisis aplicadas a las señales sísmicas registradas por los sismómetros individualmente y en su conjunto. De las distintas técnicas que se utilizan en el procesado de arrays sísmicos se ha escogido la de formación del haz (beamforming). En los arrays sísmicos actuales, las señales analógicas procedentes de cada sensor son llevadas por cable hasta el sistema de adquisición central, con la consiguiente merma en la calidad de la señal procesada. El nodo central debe realizar la adquisición de la señal de todos los sensores, establecer un control del tiempo mediante el uso de un GPS, almacenar los datos, transmitirlos, etc. A esto hay que añadir la posibilidad de que los equipos de monitorización volcánica sean destruidos, o que se agote la fuente de energía, por tanto se hace evidente la necesidad de disponer de equipos de muy bajo coste y gran autonomía, que actualmente no existen. Siguiendo esta línea de trabajo se ha diseñado una antena sísmica formada por redes de sensores inalámbricos que permitirá establecer cualquier topología de array, eliminando la necesidad de interconexión mediante cables. Esto representará un avance significativo respecto a los dispositivos existentes, tanto por la reducción de costes que implica, como por la autonomía que se consigue, lo cual permite un despliegue rápido sin necesidad de realizar una gran inversión económica. Estos equipos presentan una gran versatilidad, gracias al uso de las últimas tecnologías tanto en hardware como en software, utilizando un sistema abierto de tipo Linux embebido donde todo el software utilizado es libre. Esto permite configurar y visualizar los datos que se están registrando en tiempo real, a través de una página web y de una aplicación de mensajería instantánea, con el fin de poder realizar un seguimiento de la actividad en cualquier parte e instante. Las técnicas de localización con array se basan en la búsqueda de la máxima coherencia de las señales registradas por los distintos sensores del array, mejorando la calidad de la señal sísmica mediante la suma de la señal de cada elemento de forma coherente. Esto implica que la parte más importante en la adquisición de datos sea obtener los retardos de cada señal de forma exacta. Pruebas sintéticas muestran que un milisegundo de retardo de sincronismo deriva en un error en la determinación del ángulo de llegada por debajo de un grado. Para aumentar la precisión de sincronización de tiempo, se ha experimentado en el laboratorio con el estándar IEEE1588 PTP empleando módulos comerciales inalámbricos Xbee PRO, consiguiendo sincronización del orden del microsegundo, superiores a los requisitos del análisis de datos de array. El resultado final del trabajo de tesis ha permitido la realización de un equipo de adquisición sísmica compacto de bajo consumo (515,24mW) y coste (inferior al 10% sistemas comerciales), inalámbrico, de bajo ruido (2 bits en A/D de 24) y ligero, facilitando la posibilidad de disponer de un número significativo de unidades. El equipo ha sido validado en el laboratorio mediante sistemas de medida automatizados y procedimientos de calibración. Además se ha probado en diferentes campañas comparando el array sísmico inalámbrico desarrollado con un array de referencia cableado del IGN, ambos utilizando sensores sísmicos MARK L4 de 1 componente (vertical) y 1 segundo, siendo la relación señal/ruido de ambos equipos idéntica. Atendiendo a la tolerancia del reloj de los A/D de las diferentes estaciones del array, se ha verificado que en el peor de los casos el error de sincronismo es de 650 μs.Postprint (published version

    Diseño de herramientas y metodologías docentes innovadoras para la asignatura "Notación y Edición Musical" del Grado de Musicología

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    Diseño de herramientas y metodologías docentes innovadoras para la asignatura “Notación y Edición Musical” del Grado de Musicología (sin financiación). Carmen Julia Gutiérrez González (coord.) Facultad de Geografía e Historia, Departamento de Musicologí

    Fecal carriage of extended-spectrum beta-lactamase-producing Enterobacterales in healthy Spanish schoolchildren

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    Background: Extended-spectrum ß-lactamase-producing Enterobacterales (ESBL-E) are a serious threat among emerging antibiotic resistant bacteria. Particularly, the number of cases of ESBL-E infections reported in children has been increasing in recent years, and approved antibiotic treatments for this age group are limited. However, information regarding the prevalence of colonization in European children, risk factors associated with colonization, and the characteristics of the colonizing strains is scarce. The aims of this study were to determine the prevalence of ESBL-E colonization in fecal samples of apparently healthy schoolchildren, to identify lifestyle routines associated with colonization, and to characterize clonal relationships and mechanisms of resistance in ESBL-E isolates. Methods: A cohort of 887 healthy children (3-13 years old) from seven primary and secondary schools in the Madrid metropolitan area was recruited between April-June 2018, and sociodemographic information and daily habits were collected. Fecal samples were screened for ESBL-E carriage in selective medium. ESBL-E isolates were further characterized by assessing molecular epidemiology (PFGE and MLST), ESBL gene carriage, and antibiotic resistance profile. This information was analyzed in conjunction with the metadata of the participants in order to identify external factors associated with ESBL-E carriage. Results: Twenty four ESBL-E, all but one Escherichia coli, were detected in 23 children (prevalence: 2.6%; 95% CI: 1.6-3.6%). Of these, seven contained the blaCTX-M-14 allele, five the blaCTX-M-15, five the blaSHV-12, three the blaCTX-M-27, three the blaCTX-M-32, and one the blaCTX-M-9. Significant clonal diversity was observed among the isolates that grouped into 22 distinct clusters (at <85% similarity of PFGE profile). ESBL-producing E. coli isolates belonged to 12 different STs, with ST10 (25%) and ST131 (17%) being the most frequent. Apart from ß-lactams, resistance to trimethoprim/sulfamethoxazole (46%), ciprofloxacin (33%), levofloxacin (33%), tobramycin (21%), and gentamicin (8%) were the most frequently detected. Conclusion: The prevalence of ESBL-E in the studied cohort of children was lower than the average colonization rate previously detected in Europe for both children and adults. E. coli was the main ESBL-producing species detected and CTX-M were the most frequently identified ESBLs. High ST diversity suggests polyclonal dissemination. Compared to other STs, ST131 isolates were associated with resistance to various antimicrobials.ML-S was supported by the Sara Borrell Program of the Instituto de Salud Carlos III (ISCIII) (CD17CIII/00017). ZM was supported by the Río Hortega Program of the ISCIII. AÁ was supported by the Garantía Juvenil Program of the Comunidad Autónoma de Madrid. SS was supported by the Miguel Servet program of ISCIII (CPII18CIII/00005). This study was funded by the ISCIII, Ministry of Economy and Competitiveness (Spain), under projects PI16CIII/00024, PI18CIII/00030, MPY380/18, and MPY516/19.S

    Multiteide Project: Multiparametric characterization of the activity of Teide-Pico Viejo volcanic system

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    European Geosciences Union General Assembly (2017. Viena)Teide-Pico Viejo complex stands for one of the major natural volcanic hazards in the Canary Islands, due to the expected types of eruptions in the area and the high number of inhabitants in Tenerife Island. Therefore, it is necessary to have a volcanic alert system able to afford a precise assessment of the current state of the complex. For this purpose, the knowledge of the expected signals at each volcanic activity level is required. Moreover, the external effects that can affect the measurements shall be distinguished, external influences as the atmosphere are qualitatively known but have not been quantified yetCentro Geofísico de Canarias, Instituto Geográfico Nacional, EspañaObservatorio Geofísico Central, Instituto Geográfico Nacional, EspañaInstituto Geológico y Minero de España, EspañaLaboratoire GéoSciences Réunion, Institut de Physique du Globe de Paris, Centre National de la Recherche Scientifique, EspañaPeer reviewe

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    Hydrothermal system of Central Tenerife Volcanic Complex, Canary Islands (Spain), inferred from self-potential measurements

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    Use of cyanoacrylate adhesives in dermal lesions: a review

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    Sutures have traditionally been considered the preferred choice for the mechanical closure of tissue injuries. However, suturing implies an additional trauma to the wound. The search for a quick, painless method with good aesthetic results has prompted a number of publications and studies that have evaluated the effectiveness of synthetic tissue adhesives (cyanoacrylate adhesives) and other biological sealants (fibrin glue and others) as an alternative to standard suturing. The therapeutic applications covered by the literature on cyanoacrylate-based adhesives are most varied. This literature review seeks to show the evolution over time of the methods and results obtained by scientific research on the use of biological adhesives for dermal closure, by collecting existing data on aspects relative to cyanoacrylates and their application on dermal lesions from papers published over the past 50 years. Such a review is novel in the existing literature. In recent decades, the use of cyanoacrylate-based adhesives for the closure of dermal lesions in different surgical areas has spread thanks to the positive results reported by the vast majority of the studies. New avenues for tissue adhesive production are being explored currently. The prospects for these adhesives are positively appraised, though potential disadvantages and contraindications must be borne in mind

    Spatial and Temporal Analysis of Temperature and Gaseous Emission Inside a Gallery in An Active Volcanic Island (Tenerife, Canary Islands)

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    In Tenerife there are a vast number of sub-horizontal blind water mines, called “galleries”. Seven air and soil temperatures and CO2 concentration profiles in air were carried out inside the Río de Guía gallery (hereinafter RdG). An anomalous stable maximum temperature point (hereinafter MTP) was found around 2000 m from the entrance. During the warm period, a clear CO2 stagnation was detected before MTP, showing concentrations up to 14,000 ppm. In order to study gas emission and its dynamics inside the gallery, four stations were deployed around MTP. All stations recorded air and soil temperatures, and CO2 and Rn concentration in air from November 2009 to January 2011. After analyzing this dataset, it was possible to characterize the influence of MTP. This thermal anomaly divided the gallery into two sections. In the cold period, the outer section located outwards from MTP became colder while the inner section warmed up owing to a less heat transfer into the deepest part of the gallery. There were several short periods when variations in barometric pressure created an advection movement that was able to temporally change the gas behavior inside the gallery. Two soil gas samples were taken around MTP and their δ13C (CO2) ratios suggested a magmatic origin. All data were combined to create a model for the gas and thermal dynamics inside the gallery. This model, together with identification of background levels in each parameter, allows to identify any anomalous signal that could be elated with changes in volcanic activity.This study was funded by the Instituto Geográfico Nacional (Ministerio de Fomento, Spanish Government).Peer Reviewe

    Geochemical signals related to the 2011–2012 El Hierro submarine eruption

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    On 10 October 2011, a submarine volcanic eruption began 2 km south of the island of El Hierro (Canary Islands, Spain). It was the first eruption after 40 years of quiescence in the Canarian archipelago. Since mid-July 2011, a multiparametric network has been deployed by the Instituto Geográfico Nacional (hereinafter IGN)to monitor volcanic processes. The data recorded by five stations, measuring the air and soil temperature, CO and radon concentration in the air inside four galleries and one well, are the focus of the present paper. Two important anomalies were found that improve comprehension of the volcanic process. First, a clear increase in CO concentration in one gallery (from 825 ± 19 to 2305 ± 35 ppm)which seems to be mainly controlled by ground deformation measured during the unrest period preceding the eruption. Second, a relationship between radon concentration in air in a well located in the northern side of the island with seismic energy release (several peaks with up to 115% increase), and ground deformation (50% growth in background level), also before the eruption onset. Lastly, changes in radon concentration during eruptive period seem to be modulated by seismic activity (increases up to 233%), which in turn is likely related to variations in magma rheology.Peer Reviewe
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