SNR enhancement in high-resolution phasesensitive OTDR systems using chirped pulse amplification concepts

Phase-sensitive optical time-domain reflectometry\ud (φOTDR) is widely used for the distributed detection of\ud mechanical or environmental variations with resolutions\ud of typically a few meters. The spatial resolution of these\ud distributed sensors is related to the temporal width of\ud the input probe pulses. However, the input pulse width\ud cannot be arbitrarily reduced (to improve the resolution),\ud since a minimum pulse energy is required to achieve a good\ud level of signal-to-noise ratio (SNR), and the pulse peak\ud power is limited by the advent of nonlinear effects. In this\ud Letter, inspired by chirped pulse amplification concepts, we\ud present a novel technique that allows us to increase the SNR\ud by several orders of magnitude in φOTDR-based sensors\ud while reaching spatial resolutions in the centimeter range.\ud In particular, we report an SNR increase of 20 dB over the\ud traditional architecture, which is able to detect strain events\ud with a spatial resolution of 1.8 cm.Commission of the European Communities JointHORIZON 2020Ministerio de Economía y CompetitividadComunidad de Madri

One-pot synthesized functionalized mesoporous silica as a reversed-phase sorbent for solid-phase extraction of endocrine disrupting compounds in milks

A new procedure for the determination of 12 naturally occurring hormones and some related synthetic chemicals in milk, commonly used as growth promoters in cattle, is reported. The method is based on liquid–liquid extraction followed by solid-phase extraction (SPE) using a new one-pot synthesized ordered mesoporous silica (of the SBA-15 type) functionalized with octadecyl groups (denoted as SBA-15-C18-CO) as reversed-phase sorbent. The analytes were eluted with methanol and then submitted to HPLC with diode array detection. Under optimal conditions, the method quantification limit for the analytes ranged from 0.023 to 1.36 μg/mL. The sorbent affored the extraction of estrone, 17β-estradiol, estriol, progesterone, hexestrol, diethylstilbestrol, 4-androstene-3,17-dione, ethinylestradiol, 17α-methyltestosterone, nandrolone, prednisolone and testosterone with mean recoveries ranging from 72% to 105% (except for diethylstilbestrol) with RSD < 11%. These results were comparable and, in some cases, even better than those obtained with other extraction methods, therefore SBA-15-C18-CO mesoporous silica possess a high potential as a reversed-phase sorbent for SPE of the 12 mentioned endocrine disrupting compounds in milk samples

Bounds on spectrum graph coloring

We propose two vertex-coloring problems for graphs, endorsing the spectrum of colors with a matrix of interferences between pairs of colors. In the Threshold Spectrum Coloring problem, the number of colors is fixed and the aim is to minimize the maximum interference at a vertex (interference threshold). In the Chromatic Spectrum Coloring problem, a threshold is settled and the aim is to minimize the number of colors (among the available ones) for which respecting that threshold is possible. We prove general upper bounds for the solutions to each problem, valid for any graph and any matrix of interferences. We also show that both problems are NP-hard and perform experimental results, proposing a DSATUR-based heuristic for each problem, in order to study the gap between the theoretical upper bounds and the values obtained

Resolving 1 million sensing points in an optimized differential time‐domain Brillouin sensor

A differential pulse-width pair (DPP) Brillouin distributed fiber sensor is implemented to achieve centimetric spatial resolution over distances of several kilometers. The presented scheme uses a scanning method in which the spectral separation between the two probe sidebands is kept constant, while the optical frequency of the pump is swept to scan the Brillouin spectral response. Experimental results show that this method avoids detrimental temporal distortions of the pump pulses, which in a standard implementation prevent the DPP method from operating over mid-to-long distances. Such a novel scanning procedure allows the resolving, for the first time in pure time-domain Brillouin sensors, of 1,000,000 sensing points, i.e., 1 cm spatial resolution over 10 km in a conventional acquisition time.Commission of the European Communities JointHORIZON 2020Ministerio de Economía y CompetitividadComunidad de Madri

Capillary electrophoresis determination of non-protein amino acids as quality markers in foods

Non-protein amino acids mainly exist in food as products formed during food processing, as metabolic intermediates or as additives to increase nutritional and functional properties of food. This fact makes their analysis and determination an attractive field in food science since they can give interesting information on the quality and safety of foods. This article presents a comprehensive review devoted to describe the latest advances in the development of (achiral and chiral) analytical methodologies by capillary electrophoresis and microchip capillary electrophoresis for the analysis of non-protein amino acids in a variety of food samples. Most relevant information related to sample treatment, experimental separation and detection conditions, preconcentration strategies and limits of detection will be provided.Universidad de Alcal

Aggregating territories, integrating elites. The Southern Netherlands and the Monarchy of Philip III (1598-1621)

Este artículo analiza cómo gestionó Felipe III sus recursos de patronazgo en los años previos a la restitución de soberanía de los estados de Flandes en 1621 (honores, pensiones, cargos cortesanos, hábitos militares). El monarca trató de asegurar el éxito de la restitución estimulando y satisfaciendo las expectativas de ganancia de las élites flamencas, llamadas a interpretar la reversión territorial como algo deseable para sus intereses. Los pormenores de la política de integración de élites gestada y ejecutada por la Corona para afrontar la reincorporación a la Monarquía.This article studies how Philip III managed his royal patronage in the years before the return of the Southern Netherlands into the Spanish sovereignty in 1621 (honours, grants, court offices, military habits). The king tried to assure the success of this return stimulating and satisfying the profits expectancies of the Flemish elites, who could see this return as a positive decision for their interests. The details of the elites integration politics designed and implemented by the Crown to bring back this former patrimonial territory to the Spanish Monarchy demonstrate the practical values of some forms of belonging and some goals of identity adherence, as a service at the Royal Houses or the Catholicism’s defence.Resultado de los proyectos I + D del Ministerio de Ciencia e Innovación (ref. HUM200609833HIST y HAR2009-12963-C03-02/HIS) ejecutados desde la Fundación Carlos de Amberes y la Universidad de Alcal

La malnutrición un problema de salud global y el derecho a una alimentación adecuada.

En el presente trabajo los autores analizan desde diferentes perspectivas el problema de la\ud malnutrición en el mundo, por exceso y por defecto, como un problema de salud global al que se\ud enfrenta la humanidad. Se aclara la terminología para referirse a este problema, se realiza un repaso\ud sobre los índices sintéticos que aportan una cifra global sobre el hambre, se valoran los aspectos\ud clínicos derivados de la falta y del exceso de nutrientes y se sitúa el Objetivo de Desarrollo Sostenible\ud (ODS) número 2 en el contexto del compromiso sobre su cumplimento en relación a los acuerdos de\ud la Asamblea General de la ONU, en consonancia con la nueva Agenda 2030 para el Desarrollo\ud Sostenible.In this paper the authors analyze from different perspectives the problem of malnutrition\ud in the world, by excess and by defect, as a global health problem facing humanity. The terminology\ud is clarified to refer to this problem, a review is done on the synthetic indexes that contribute give a\ud global figure on hunger, the clinical aspects derived from lack and excess of nutrients are valued and\ud the Sustainable Development Objective (ODS) number 2 in the context of the commitment on its\ud compliance with the UN General Assembly agreements, in line with the new Agenda 2030 for\ud Sustainable Development

Magnetic clouds seen at different locations in the heliosphere

We analyze two magnetic clouds (MCs) observed in different points of the heliosphere. The main aim of the present study is to provide a link between the different aspects of this phenomenon, starting with information on the origins of the MCs at the Sun and following by the analysis of in-situ observations at 1AU and at Ulysses. The candidate source regions were identified in SOHO/EIT and SOHO/MDI observations. They were correlated with H-alfa images that were obtained from ground-based observatories. Hints on the internal magnetic field configuration of the associated coronal mass ejections are obtained from LASCO C2 images. In interplanetary space, magnetic and plasma moments of the distribution function of plasma species (ACE/Ulysses) were analyzed together with information on the plasma composition, and the results were compared between both spacecraft in order to understand how these structures interact and evolve in their cruise from the Sun to 5 AU. Additionally, estimates of global magnitudes of magnetic fluxes and helicity were obtained from magnetic field models applied to the data in interplanetary space. We have found that these magnetic characteristics were well kept from their solar source, up to 5 AU where Ulysses provided valuable information which, together with that obtained from ACE, can help to reinforce the correct matching of solar events and their interplanetary counterparts.Ministerio de Educación y Cultur

Tratamiento farmacológico de la depresión: comparación entre las principales Guías de Práctica Clínica

La depresión supone un problema sanitario de primera magnitud, por su alta prevalencia\ud y su impacto sobre la funcionalidad y calidad de vida de los pacientes. Su tratamiento efectivo suele\ud incluir el abordaje farmacológico, que debe basarse en las pruebas disponibles y seguir las\ud recomendaciones generales de manejo de las Guías de Práctica Clínica (GPC). El presente trabajo\ud pretende, a través de la búsqueda en diferentes bases de datos (Medline, Scopus, PubMed, Web of\ud Science y PsycINFO) y la revisión de las principales GPC internacionales, comparar las distintas\ud recomendaciones dadas sobre el tratamiento farmacológico de la depresión. Se revisan las\ud similitudes y discrepancias sobre: elección de antidepresivo y tratamientos asociados, duración del\ud tratamiento tras la remisión, prevención de recaídas, retirada de fármacos y estrategias de actuación\ud ante la falta de respuesta.Depression is a major health problem due to its high prevalence and its impact on patient´s\ud functioning and quality of life. Its effective treatment usually includes the pharmacological\ud approach, which should be based on available evidence and follow the general recommendations of\ud the Clinical Practice Guidelines (CPG). Through the search in different databases (Medline, Scopus,\ud PubMed, Web of Science and PsycINFO) and the review of the main international CPGs, the present\ud work aims to compare the different recommendations given on the pharmacological treatment of\ud depression. The similarities and discrepancies are reviewed for: choice of antidepressant and\ud associated treatments, duration of treatment after remission, prevention of relapse, withdrawal of\ud drugs and strategies of action in the absence of response

A novel fiber optic based surveillance system for prevention of pipeline integrity threats

This paper presents a novel surveillance system aimed at the detection and classification of threats in the vicinity of a long gas pipeline. The sensing system is based on phase-sensitive optical time domain reflectometry (φ-OTDR) technology for signal acquisition and pattern recognition strategies for threat identification. The proposal incorporates contextual information at the feature level and applies a system combination strategy for pattern classification. The contextual information at the feature level is based on the tandem approach (using feature representations produced by discriminatively-trained multi-layer perceptrons) by employing feature vectors that spread different temporal contexts. The system combination strategy is based on a posterior combination of likelihoods computed from different pattern classification processes. The system operates in two different modes: (1) machine + activity identification, which recognizes the activity being carried out by a certain machine, and (2) threat detection, aimed at detecting threats no matter what the real activity being conducted is. In comparison with a previous system based on the same rigorous experimental setup, the results show that the system combination from the contextual feature information improves the results for each individual class in both operational modes, as well as the overall classification accuracy, with statistically-significant improvements