944 research outputs found

    Composition law of cardinal order permutations

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    In this paper the theorems that determine composition laws for both cardinal ordering permutations and their inverses are proven. So, the relative positions of points in a hs-periodic orbit become completely known as well as in which order those points are visited. No matter how a hs-periodic orbit emerges, be it through a period doubling cascade (s=2^n) of the h-periodic orbit, or as a primary window (like the saddle-node bifurcation cascade with h=2^n), or as a secondary window (the birth of a ss-periodic window inside the h-periodic one). Certainly, period doubling cascade orbits are particular cases with h=2 and s=2^n. Both composition laws are also shown in algorithmic way for their easy use

    Population structure of Asconema setubalense Kent, 1870 at Concepción Seamount, Canary Islands (Spain). Methodological approach using non-invasive techniques

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    The hexactinellid sponge Asconema setubalense Kent, 1870is a large bathyal species of the North Atlantic Ocean with a funnel-like body and very large osculum. Populations of A. setubalense have a three-dimensional structure and increase the complexity and biodiversity in their habitat, and are therefore considered to be a habitat-forming species. Nevertheless, at present the information on the extension, biomass, density, population structure, and ecology of this species is scarce, and it could be susceptible to the longline fishing practices that take place in the Canary Islands. The main objectives of this study are to define a functional and accurate methodology to measure specimens of A. setubalense by comparing differences in users, techniques, and morphometric measurements; to describe the height-size relationship; to present the population size structure of the species, and to establish a relationship between the size of A. setubalense and the environmental variables that can be found at the “Banco de La Concepción” seamount (BC). The obtained results suggest that surface area is the most reliable measurement to define the size of this species, whilst also showing a clear correlation with the height of the species. The selected methodology has made it possible to measure the surface area of 1035 specimens and thus obtain the size structure of the population of A. setubalense in BC. The GAM model that was used to analyse the relationship between the size of A. setubalense and the geomorphologic variables of BC, shows areas where there is a high probability of finding large specimens of the species. The results of this study greatly enhance the knowledge of this species and its habitat, and should be considered in future conservation directives, or in the development of indicators to show the good environmental state of habitats. Additionally, the study improves analysis methodology that, with the appropriate morphometric measurements, can favour the development of future studies of this species, and indeed others with a similar morphology or growth pattern.En prensa2,42

    Identification of the key excreted molecule by Lactobacillus fermentum related to host iron absorption

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    We have taken a vital step towards understanding why probiotic bacteria increase iron absorption in the gastrointestinal tract. We show here that Lactobacillus fermentum, one of the main probiotics of the microbiota, exhibits an extraordinary ferric-reducing activity. This activity is predominantly due to an excreted molecule: p-hydroxyphenyllactic acid (HPLA). Reduction of Fe(III) to Fe(II) is essential for iron absorption in the gastrointestinal tract. By reducing Fe(III), HPLA boosts Fe(II) absorption through the DMT1 channels of enterocytes. An in vitro experiment tested and confirmed this hypothesis. This discovery opens new avenues for the treatment of iron deficiency in humans, one of the most common and widespread nutritional disorders in the world

    Use of discontinuity factors in high-order finite element methods

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    The discontinuity factors are a technique widely used in nodal methods to minimize the error due to spatial homogenization of cross sections for a coarse mesh core calculation. In the present work, the introduction of discontinuity factors in a high-order finite element approximation of the neutron diffusion equation is investigated. More precisely, classical reference and assembly discontinuity factors are introduced in a discontinuous Galerkin finite element method stabilized using an interior penalty formulation for the neutron diffusion equation. The proposed method is tested solving different one- and two-dimensional benchmark problems, showing that the discontinuity factors technique can be successfully introduced in the discontinuous Galerkin formulation. (C) 2015 Published by Elsevier Ltd.The work performed by the second, fifth, and sixth author was financially supported by the Swedish Research Council (VR - Vetenskapsradet) within a framework grant called DREAM4SAFER (Development of Revolutionary and Accurate Methods for Safety Analyses of Future and Existing Reactors), research contract C0467701.Vidal-Ferràndiz, A.; González Pintor, S.; Ginestar Peiro, D.; Verdú Martín, GJ.; Asadzadeh, M.; Demazière, C. (2016). Use of discontinuity factors in high-order finite element methods. Annals of Nuclear Energy. 87:728-738. https://doi.org/10.1016/j.anucene.2015.06.021S7287388

    Remote Interactions between tropical cyclones: The case of Hurricane Michael and Leslie’s high predictability uncertainty

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    The study explores Hurricane Michael’s impact on Hurricane Leslie’s trajectory predictability using ECMWF and NCEP ensemble systems. A clustering method focused on tropical cyclones is used to identify potential paths for Leslie: Cluster 1 accurately predicted Leslie’s direction towards the Iberian Peninsula, whereas Clusters 2 and 3 indicated a southern recurve near the Canary Islands. Analysis of potential vorticity and irrotational wind at upper levels showed a significant interaction between Michael, ridge, and trough across the jet stream from +12 h after initialization. Cluster 1 showed a stronger Michael promoting upper-level wind divergence greatest, modifying the jet stream configuration around the ridge and downstream. Alterations in the jet stream’s configuration, functioning as a waveguide, propagated downstream, guiding Leslie towards the Iberian Peninsula. Clusters 2 and 3 indicated the trough’s failure to incorporate Leslie, resulting in a recurve of the trajectory around the Azores anticyclone. This research enhances comprehension of the interaction between two tropical cyclones via synoptic Rossby wave flow. Moreover, the conceptual framework can aid operational meteorologists in identifying the sources of uncertainty, particularly in track forecasts under synoptic conditions analogous to those examined in this study.This work was partially supported by the research project PID2019-105306RB-I00/AEI/ 10.13039/501100011033 (IBERCANES), and the two ECMWF Special Projects (SPESMART and SPESVALE). Mauricio López-Reyes extends his sincere gratitude to Professor Héctor Ulloa-Godínez from the Institute of Astronomy and Meteorology at the University of Guadalajara for his invaluable support. He also acknowledges Instituto Frontera A.C. for their partial funding of this work. C. Calvo-Sancho acknowledges the grant awarded by the Spanish Ministry of Science and Innovation - FPI Program (PRE2020-092343)

    Biodiversidad de los LIC Banco de La Concepción y Espacil marino del oriente y sur de Lanzarote-Fuerteventura. Especies protegidas y formadoras de hábitats

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    Two large areas belonging to the Canary Islands marine demarcation are part of the Natura 2000 network as Sites of Community Importance (SCI): “ESZZ15001-Banco de la Concepción” (total area 609,721.92 ha; depth range 158-2,687 m) and “ESZZ15002-Espacio marino del oriente y sur de Lanzarote y Fuerteventura” (total area 1,433,248.92 ha; depth range 0-3,300 m). Within the framework of the LIFE INTEMARES IP project, Action A.2.1, and before the designation of these two SCIs as Special Areas of Conservation, the Spanish Institute of Oceanography (IEO) is responsible for completing information necessary for the development of management plans. In the present study, a general analysis of the biodiversity of the two SCIs is carried out, starting from the updated catalogs, based mainly on previous IEO research and on information from the Canary Islands Biodiversity Data Bank, a comprehensive database of the Regional Government that draws on all current and historical information, backed by documents supervised by specialists. Special emphasis is placed on protected species and habitat forming species, which are considered key elements for management.Dos grandes zonas de la demarcación marina de las islas Canarias forman parte de la Red Natura 2000 como Lugares de Importancia Comunitaria (LIC): “ESZZ15001-Banco de la Concepción” (área total 609.721,92 ha; rango de profundidad 158-2.687 m) y “ESZZ15002-Espacio marino del oriente y sur de Lanzarote y Fuerteventura” (área total 1.433.248,92 ha; rango de profundidad 0-3.300 m). El Instituto Español de Oceanografía (IEO) ha sido encargado de completar la información necesaria para el desarrollo de los planes de gestión, como paso previo a la declaración de estos LIC como Zonas de Especial Conservación, en el marco del proyecto LIFE IP INTEMARES, Acción A.2.1. En el presente trabajo se realiza un análisis general de la biodiversidad de los dos LIC, partiendo de los catálogos actualizados, basados principalmente en investigaciones previas del IEO y en la información del Banco de Datos de Biodiversidad de Canarias, una completa base de datos que recopila toda la información actual e histórica, respaldada por documentos supervisados por especialistas. Se presta una especial atención a las especies protegidas y a las formadoras de hábitats, que son consideradas elementos claves para la gestiónTwo large areas belonging to the Canary Islands marine demarcation are part of the Natura 2000 network as Sites of Community Importance (SCI): “ESZZ15001-Banco de la Concepción” (total area 609,721.92 ha; depth range 158-2,687 m) and “ESZZ15002-Espacio marino del oriente y sur de Lanzarote y Fuerteventura” (total area 1,433,248.92 ha; depth range 0-3,300 m). Within the framework of the LIFE INTEMARES IP project, Action A.2.1, and before the designation of these two SCIs as Special Areas of Conservation, the Spanish Institute of Oceanography (IEO) is responsible for completing information necessary for the development of management plans. In the present study, a general analysis of the biodiversity of the two SCIs is carried out, starting from the updated catalogs, based mainly on previous IEO research and on information from the Canary Islands Biodiversity Data Bank, a comprehensive database of the Regional Government that draws on all current and historical information, backed by documents supervised by specialists. Special emphasis is placed on protected species and habitat forming species, which are considered key elements for management.En prens

    Case Study based on Inequality Indices for the Assessments of Industrial Fleets

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    3rd IFAC Workshop on Advanced Maintenance Engineering, Services and Technology AMEST 2016: Biarritz, France, 19—21 October 2016. - IFAC-PapersOnLine, Volume 49, Issue 28, 2016, Pages 250-255This contribution illustrates the advantages of measures and indicators based on the notions of Shannon entropy which is widely implemented in thermodynamics, information theory, econometrics, and biology. The presented case study applies these indicators to a fleet of industrial assets, introducing innovatively the entropy concept to the field of availability. There is no reason to deal the effect of performance variables in assets independently without taking into account disparities in terms of reliability, operation hours, applied maintenance, operating conditions, and usage profiles, etc. Therefore, the characteristic of the method and their independence from the heterogeneity of the sample that compares is intended to be promising for applications in availability analysis. In other words, this research presents a derivation from well-known concepts such as the Gini, Hoover and Theil indices illustrating their application by the support of an example where attributes for different groups of assets are compared. To illustrate the application we are using two relevant and innovative scenarios as case study examples

    On the impact of initial conditions in the forecast of Hurricane Leslie extratropical transition

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    Hurricane Leslie (2018) was a non-tropical system that lasted for a long time undergoing several transitions between tropical and extratropical states. Its trajectory was highly uncertain and difficult to predict. Here the extratropical transition of Leslie is simulated using the Model for Prediction Across Scales (MPAS) with two different sets of initial conditions (IC): the operational analysis of the Integrate Forecast System (IFS) and the Global Forecast System (GFS).This work was partially supported by the research project PID2019-105306RB-I00/AEI/10.13039/501100011033, and the two ECMWF Special Projects (SPESMART and SPESVALE)

    Advances in seismic monitoring at Deception Island volcano (Antarctica) since the International Polar Year

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    Deception Island is an active volcano located in the south Shetland Islands, Antarctica. It constitutes a natural laboratory to test geophysical instruments in extreme conditions, since they have to endure not only the Antarctic climate but also the volcanic environment. Deception is one of the most visited places in Antarctica, both by scientists and tourists, which emphasize the importance of volcano monitoring. Seismic monitoring has been going on since 1986 during austral summer surveys. The recorded data include volcano-tectonic earthquakes, long-period events and volcanic tremor, among others. The level of seismicity ranges from quiet periods to seismic crises (e.g. 1992-1993, 1999). Our group has been involved in volcano monitoring at Deception Island since 1994. Based on this experience, in recent years we have made the most of the opportunities of the International Polar Year 2007-2008 to introduce advances in seismic monitoring along four lines: (1) the improvement of the seismic network installed for seismic monitoring during the summer surveys; (2) the development and improvement of seismic arrays for the detection and characterization of seismo-volcanic signals; (3) the design of automated event recognition tools, to simplify the process of data interpretation; and (4) the deployment of permanent seismic stations. These advances help us to obtain more data of better quality, and therefore to improve our interpretation of the seismo-volcanic activity at Deception Island, which is a crucial step in terms of hazards assessment.This work has been partially supported by the projects POL2006-08663, CGL2007-28855, CTM2008-03062, CTM2009-07705, CTM2009-08085 and CTM2010-11740 of the Spanish Ministry of Science and Innovation
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