185 research outputs found

    Migration strategies toward all optical metropolitan access rings

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    This paper was published in Journal of Lightwave Technology and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the IEEE website: http://dx.doi.org/10.1109/JLT.2007.901325. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Nowadays, network operators are steadily deploying optical circuit switching (OCS) equipment in their metropolitan networks in order to cope with traffic increase and, most importantly, in order to reduce capital expenditures and operational expenditures of existing active technologies. On the other hand, optical burst switching (OBS) technology is expected to become mature in the medium term, and it may be used as an alternative to current OCS networks due to its potential advantages in terms of bandwidth allocation granularity. While OBS is being extensively studied in the literature, little attention has been paid in conducting a comparative analysis of OBS versus OCS, especially concerning cost analysis. In this paper, we provide a comparative analysis of OBS versus OCS as an evolutionary technology for all-optical rings in the metropolitan-access network. This paper is specifically targeted toward optimizing the number of optoelectronic receivers and wavelengths with real traffic matrices from the metropolitan rings in Madrid, Spain. Such matrices also include traffic projections of foreseeable broadband services, which are based on a market analysis from the largest operator in Spain. Our findings show that OCS might be more efficient than OBS in the metro-access segment, which is characterized by a highly centralized traffic pattern. However, the more distributed the traffic is, the more efficient the OBS is as well. Consequently, OBS might be better suited to metro-core networks, which show a more distributed and dynamic traffic pattern.The authors would like to thank the e-Photon/ONe+ network of excellenc

    A comparison of Covid-19 early detection between convolutional neural networks and radiologists

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    [EN] Background The role of chest radiography in COVID-19 disease has changed since the beginning of the pandemic from a diagnostic tool when microbiological resources were scarce to a different one focused on detecting and monitoring COVID-19 lung involvement. Using chest radiographs, early detection of the disease is still helpful in resource-poor environments. However, the sensitivity of a chest radiograph for diagnosing COVID-19 is modest, even for expert radiologists. In this paper, the performance of a deep learning algorithm on the first clinical encounter is evaluated and compared with a group of radiologists with different years of experience. Methods The algorithm uses an ensemble of four deep convolutional networks, Ensemble4Covid, trained to detect COVID-19 on frontal chest radiographs. The algorithm was tested using images from the first clinical encounter of positive and negative cases. Its performance was compared with five radiologists on a smaller test subset of patients. The algorithm's performance was also validated using the public dataset COVIDx. Results Compared to the consensus of five radiologists, the Ensemble4Covid model achieved an AUC of 0.85, whereas the radiologists achieved an AUC of 0.71. Compared with other state-of-the-art models, the performance of a single model of our ensemble achieved nonsignificant differences in the public dataset COVIDx. Conclusion The results show that the use of images from the first clinical encounter significantly drops the detection performance of COVID-19. The performance of our Ensemble4Covid under these challenging conditions is considerably higher compared to a consensus of five radiologists. Artificial intelligence can be used for the fast diagnosis of COVID-19.Project Chest screening for patients with COVID 19 (COV2000750 Special COVID19 resolution) funded by Instituto de Salud Carlos III. Project DIRAC (INNVA1/2020/42) funded by the Agencia Valenciana de la Innovacion, Generalitat Valenciana.Albiol Colomer, A.; Albiol, F.; Paredes Palacios, R.; Plasencia-Martínez, JM.; Blanco Barrio, A.; García Santos, JM.; Tortajada, S.... (2022). A comparison of Covid-19 early detection between convolutional neural networks and radiologists. Insights into Imaging. 13(1):1-12. https://doi.org/10.1186/s13244-022-01250-311213

    The origin and collapse of rock glaciers during the Bølling-Allerød interstadial: A new study case from the Cantabrian Mountains (Spain)

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    © 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).During the Late Pleistocene, the main mountain ranges of the Iberian Peninsula were covered by small icefields and cirque and alpine glaciers. The deglaciation triggered paraglacial processes that generated landforms, mostly within the ice-free glacial cirques. In this research we analyse the deglaciation process in the Muxivén Cirque (42°15′N – 6°16′W), in the upper Sil River Basin, which includes some of the largest relict rock glaciers of the Cantabrian Mountains. We addressed this objective by means of accurate geomorphological reconstructions, sedimentological analysis, Schmidt-hammer surface weathering measurements and a dataset of 10 10Be Cosmic-Ray Exposure ages. Results reveal that after ~16 ka, glaciers retreated to the bottom of the cirques at the headwaters of the valley, leaving the walls free of ice and triggering rock avalanches onto the remnants of these glaciers. This paraglacial process supplied debris to a small glacier within Muxivén Cirque, which transformed in two rock glaciers. These debris isolated the ice inside the rock glaciers only for a very short period of time and ended up melting completely before the Younger Dryas. The lower sector of the largest one stabilized at 14.5 ± 1.5 ka, while the upper sector remained active until 13.5 ± 0.8 ka. Previous to the stabilization of the lower sector of the northern rock glacier, at its margin a high-energy debris avalanche occurred at ~14.0 ± 0.9 ka. These data agree with previous research, corroborating the paraglacial origin of most Iberian rock glaciers during the Bølling-Allerød interstadial.This research was supported by the project LE080G19 (Paleo-environmental significance and relationship with the global change of the Cantabrian Mountains rock glaciers: relative age dating and analysis of the internal structure using electrical tomography), founded by the Junta de Castilla y León and PR108/20-20 (Santander Bank-UCM Projects). José M. Fernández-Fernández is supported by a postdoctoral grant within the NUNANTAR project, funded by the Fundação para a Ciência e Tecnologia of Portugal (PTDC/CTA-GFI/32002/2017). Marc Oliva is supported by the Ramón y Cajal Program (RYC-2015-17597) and by the Research Group ANTALP (Antarctic, Arctic, Alpine Environments; 2017-SGR-1102) funded by the Government of Catalonia. Adrián Melón-Nava was supported by the FPU program from the Spanish Ministerio de Universidades (FPU20/01220).Peer reviewe

    Revista de Vertebrados de la Estación Biológica de Doñana

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    Contribución al estudio de la bermejuela Rutilus arcasi, Steindachner, 1866 de la cuenca del Júcar (Osteichthyes: Cyprinidae)II. Edad y crecimientoSobre la taxonomía de Barbus comiza Steindachner, 1865 (Ostariophysi: Cyprinidae)Fenología de una comunidad de anfibios asociada a cursos fluviales temporales.Nueva especie para la ciencia de Anolis (Lacertilia: Iguanidae) de Cuba pertenecient eal complejo argillaceusSegregación ecológica en una comunidad de ofidios.El Aguila Imperial (Aquila adalberti): dispersión de los jóvenes, estructura de edades y mortalidaSobre diferencias individuales en la alimentación de Tyto albaInfluencia de las condiciones ambientales sobre la organización de la comunidad de aves invernantes en un bosque subalpino mediterráneoVariaciones en la agregación y distribución de la cabra montés (Capra pyrenaica Schinz,1838) detectadas con un muestreo de excrementosAlimentación del conejo (Oryctolagus cuniculus L. 1758) en Doñana. SO, EspañaSobre la distribución de Barbus meridionales Risso, 1826 (Ostariophysi: Cyprinidae) en la Península IbéricaSobre la distribución de Barbus meridionales Risso, 1826 (Ostariophysi: Cyprinidae) en la Península IbéricaNueva cita de Barbus microcephalus Almaça (Pisces, Cyprinidae) en España.Revisión taxonómica y distribución de Cobitis maroccana Pellegrin, 1929 (Osteichthyes, Cobitidae)Datos sobre una población de Lacerta viviparaSobre la presencia de Emys orbicularis en la provincia de León.Algunas observaciones sobre la captura de quirópteros por Falco subbuteo y Falco tinunculusNyctalus leisleri (Kuhk, 1818) (Mammalia: Chiroptera). Una nueva especie para las islas CanariaNuevos datos acerca de la distribución del topillo campesino Microtus arvalis, PALLAS 1778, en la Península IbéricaPeer reviewe

    Évaluation de l’aléa et du risque sismique en Haïti dirigée vers la conception parasismique

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    Après le séisme qui eut lieu en Haïti le 12 janvier 2010, dont l’épicentre a été localisé non loin de la capitale, Port-au-Prince (25 km en direction sud-est), d’une magnitude Mw 7.0 et à une profondeur de 13 km, le pays s’est retrouvé dans une situation catastrophique et d’extrême pauvreté, avec des graves carences en matière de santé, nutrition, éducation et logement. Les effets du tremblement de terre ont été dévastateurs pour la population : on compte plus de 300.000 morts, presque autant de blessés et 1,3 millions de sans-abri logès dans des campements « provisoires ». Quant aux conséquences matérielles, le séisme a totalement détruit près de 100.000 maisons et endommagé près de 200.000 (source : USGS). Ce tremblement de terre a été le plus fort enregistré dans la zone depuis 1770. De plus le séisme fut perceptible dans des pays voisins comme Cuba, la Jamaïque et la République Dominicaine, où il a provoqué l’alarme et des évacuations préventives. La reconstruction du pays reste un sujet prioritaire pour la coopération internationale. Le présent projet, SISMO-HAITÍ, a été développé dans le but d’apporter la connaissance et l’information nécessaires afin de faciliter la prise de mesures préventives face au risque sismique existant, afin d’éviter qu’un éventuel futur séisme ne déclenche une nouvelle catastrophe. Dans le cas d’Haïti, aucune institution n’était chargée d’assurer une surveillance sismique, mais un contact direct a été établi avec l’Observatoire National de l’Environnement et de la Vulnérabilité (ONEV) en Haïti à travers son directeur Dwinel Belizaire Ing. M. Sc., qui est précisément celui qui a sollicité l’aide qui a motivé la présente proposition. Le but ultime de ce projet est l’étude des mesures d’atténuation du risque élevé qui demeure, contribuant ainsi au développement durable de la région. Dans cette optique, la menace sismique en Haïti a été évaluée, constituant la base sur laquelle on prétend élaborer des critères de conception parasismique pour la reconstruction du pays qui pourront être inclus dans la première version de la norme antisismique, ainsi que le risque sismique à Port-au-Prince, dont les résultats serviront de base pour élaborer les plans d’urgence face à ce risque naturel. Les objectifs spécifiques atteints sont : • Évaluation de l'aléa sismique en Haïti. On en obtient des cartes de différents paramètres de mouvement pour différentes probabilités de dépassement (ce qui suppose connaître la probabilité associée aux mouvements dus à des tremblements futurs). • Évaluation de l'effet local à Port-au-Prince et élaboration d'une carte de microzonage de la ville. • Étude de la vulnérabilité sismique locale à Port-au-Prince. • Estimation du risque sismique à Port-au-Prince. • Mesures d'atténuation du risque et de conception parasismique. Ce rapport résume les activités et les résultats obtenus a cours de l'année 2011 lors de la mise en œuvre de ce projet. Le groupe de travail est une équipe multidisciplinaire composée de chercheurs de différents établissements universitaires et de recherche (Université Polytechnique de Madrid-UPM-, Conseil Supérieur de la Recherche Scientifique (CSIC) ; U. Complutense de Madrid-UCM-, U-UA-Alicante, Almeria-UAL-U., U. Autonome de Saint-Domingue, UASD et Université de Porto Rico Mayagüez--UPRM) experts dans les diverses matières impliquées dans le projet: géologie, sismologie, génie parasismique, architecture et gestion de l'information géographique. Tous les membres de cette équipe ont travaillé ensemble tout au long de l'année, en réalisant des réunions, des ateliers de travail, des vidéoconférences, en plus d'une visite à Port-au-Prince en Juillet 2011 afin de procéder à la première collecte de données

    Evaluación de la peligrosidad y el riesgo sísmico en Haití y aplicación al diseño sismorresistente

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    Tras el terremoto ocurrido en Haití el 12 de enero de 2010, con un epicentro próximo a la capital, Puerto Príncipe (25 km), de magnitud Mw 7,0 y profundidad de 13 km, el país ha quedado en una situación catastrófica y de extrema pobreza, con necesidades básicas de salud, nutrición, educación y habitabilidad. Los efectos del terremoto han sido devastadores en la población, con más de 300.000 personas que han perdido la vida, otras tantas que han resultado heridas y 1,3 millones de personas que han quedado sin hogar y viviendo en campamentos. En cuanto a los efectos materiales, el sismo ha dejado cerca de 100.000 residencias totalmente destruidas y casi 200.000 dañadas fuertemente (fuente: USGS). Este terremoto ha sido el más fuerte registrado en la zona desde el acontecido en 1770. Además, el sismo fue perceptible en países cercanos como Cuba, Jamaica y República Dominicana, donde provocó temor y evacuaciones preventivas. La reconstrucción del país es un tema prioritario en el marco de la cooperación internacional y el presente proyecto, SISMO-HAITÍ, se ha desarrollado con el fin de aportar conocimiento e información para facilitar la toma de medidas preventivas ante el riesgo sísmico existente, tratando de evitar que un terremoto futuro en el país produzca una catástrofe como el recientemente vivido. En el caso de Haití, no existía ninguna institución responsable del monitoreo sísmico, pero se ha establecido contacto directo con el Observatorio Nacional de Medio Ambiente y Vulnerabilidad de Haití (ONEV) a través de su director Dwinel Belizaire Ing. M. Sc. Director, que es precisamente quien ha solicitado la ayuda que ha motivado la presente propuesta. El fin último de este proyecto es el estudio de acciones de mitigación del elevado riesgo existente, contribuyendo al desarrollo sostenible de la región. Para ello, se ha evaluado la amenaza sísmica en Haití, en base a la cual se pretenden establecer criterios de diseño sismorresistente para la reconstrucción del país, que se podrán recoger en la primera normativa antisísmica, así como el riesgo sísmico en Puerto Príncipe, cuyos resultados servirán de base para elaborar los planes de emergencia ante este riesgo natural. Los objetivos específicos alcanzados son: • Evaluación de amenaza sísmica en Haití, resultando mapas de distintos parámetros de movimiento para diferentes probabilidades de excedencia (lo que supone conocer la probabilidad asociada a movimientos por futuros terremotos). • Evaluación del efecto local en Puerto Príncipe y elaboración de un mapa de microzonación de la ciudad. • Estudio de vulnerabilidad sísmica a escala local en Puerto Príncipe • Estimación del riesgo sísmico en Puerto Príncipe • Medidas de mitigación del riesgo y de diseño sismorresistente En este informe se resumen las actividades desarrolladas y los resultados obtenidos a lo largo del año 2011 durante la ejecución del presente proyecto. El grupo de trabajo es un equipo multidisciplinar, compuesto por investigadores de diferentes universidades (Universidad Politécnica de Madrid- UPM-, U. Complutense de Madrid -UCM-, U. Alicante -UA-, U. Almería -UAL-, U. Autónoma de Santo Domingo -UASD- y U. de Mayagüez de Puerto Rico -UPRM-) que cubren todas las ramas involucradas en la ejecución del proyecto: geología, sismología, ingeniería sísmica, arquitectura y gestión de geoinformación. Todos los miembros de este equipo han trabajado conjuntamente durante todo el año, manteniendo reuniones, jornadas de trabajo y videoconferencias, además de realizar una visita a Puerto Príncipe en julio de 2011 para llevar a cabo la primera toma de datos

    Shells and humans: molluscs and other coastal resources from the earliest human occupations at the Mesolithic shell midden of El Mazo (Asturias, Northern Spain)

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    Human populations exploited coastal areas with intensity during the Mesolithic in Atlantic Europe, resulting in the accumulation of large shell middens. Northern Spain is one of the most prolific regions, and especially the so-called Asturian area. Large accumulations of shellfish led some scholars to propose the existence of intensification in the exploitation of coastal resources in the region during the Mesolithic. In this paper, shell remains (molluscs, crustaceans and echinoderms) from stratigraphic units 114 and 115 (dated to the early Mesolithic c. 9 kys cal BP) at El Mazo cave (Asturias, northern Spain) were studied in order to establish resource exploitation patterns and environmental conditions. Species representation showed that limpets, top shells and sea urchins were preferentially exploited. One-millimetre mesh screens were crucial in establishing an accurate minimum number of individuals for sea urchins and to determine their importance in exploitation patterns. Environmental conditions deduced from shell assemblages indicated that temperate conditions prevailed at the time of the occupation and the morphology of the coastline was similar to today (rocky exposed shores). Information recovered relating to species representation, collection areas and shell biometry reflected some evidence of intensification (reduced shell size, collection in lower areas of exposed shores, no size selection in some units and species) in the exploitation of coastal resources through time. However, the results suggested the existence of changes in collection strategies and resource management, and periods of intense shell collection may have alternated with times of shell stock recovery throughout the Mesolithic.This research was performed as part of the project “The human response to the global climatic change in a littoral zone: the case of the transition to the Holocene in the Cantabrian coast (10,000–5000 cal BC) (HAR2010-22115-C02-01)” funded by the Spanish Ministry of Economy and Competitiveness. AGE was funded by the University of Cantabria through a predoctoral grant and IGZ was funded by the Spanish Ministry of Economy and Competitiveness through a Juan de la Cierva grant. We also would like to thank the University of Cantabria and the IIIPC for providing support, David Cuenca-Solana, Alejandro García Moreno and Lucia Agudo Pérez for their help. We also thank Jennifer Jones for correcting the English. Comments from two anonymous reviewers helped to improve the paper

    Effect of a nutritional intervention based on an energy-reduced Mediterranean diet on environmental impact

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    [EN]To estimate the environmental impact of a dietary intervention based on an energy-reduced Mediterranean diet (MedDiet) after one year of follow-up. Methods Baseline and 1-year follow-up data were used for 5800 participants aged 55–75 years with metabolic syndrome in the PREDIMED-Plus study. Food intake was estimated through a validated semiquantitative food consumption frequency questionnaire, and adherence to the MedDiet was estimated through the Diet Score. Using the EAT-Lancet Commission tables we assessed the influence of dietary intake on environmental impact (through five indicators: greenhouse gas emissions (GHG), land use, energy used, acidification and potential eutrophication). Using multivariable linear regression models, the association between the intervention and changes in each of the environmental factors was assessed. Mediation analyses were carried out to estimate to what extent changes in each of 2 components of the intervention, namely adherence to the MedDiet and caloric reduction, were responsible for the observed reductions in environmental impact. Results We observed a significant reduction in the intervention group compared to the control group in acidification levels (−13.3 vs. -9.9 g SO2-eq), eutrophication (−5.4 vs. -4.0 g PO4-eq) and land use (−2.7 vs. -1.8 m2). Adherence to the MedDiet partially mediated the association between intervention and reduction of acidification by 15 %, eutrophication by 10 % and land use by 10 %. Caloric reduction partially mediated the association with the same factors by 55 %, 51 % and 38 % respectively. In addition, adherence to the MedDiet fully mediated the association between intervention and reduction in GHG emissions by 56 % and energy use by 53 %.SIPublicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL

    Contrasting Microbial Community Assembly Hypotheses: A Reconciling Tale from the Río Tinto

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    The Río Tinto (RT) is distinguished from other acid mine drainage systems by its natural and ancient origins. Microbial life from all three domains flourishes in this ecosystem, but bacteria dominate metabolic processes that perpetuate environmental extremes. While the patchy geochemistry of the RT likely influences the dynamics of bacterial populations, demonstrating which environmental variables shape microbial diversity and unveiling the mechanisms underlying observed patterns, remain major challenges in microbial ecology whose answers rely upon detailed assessments of community structures coupled with fine-scale measurements of physico-chemical parameters.By using high-throughput environmental tag sequencing we achieved saturation of richness estimators for the first time in the RT. We found that environmental factors dictate the distribution of the most abundant taxa in this system, but stochastic niche differentiation processes, such as mutation and dispersal, also contribute to observed diversity patterns.We predict that studies providing clues to the evolutionary and ecological processes underlying microbial distributions will reconcile the ongoing debate between the Baas Becking vs. Hubbell community assembly hypotheses
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