97 research outputs found

    Harmonic states for the free particle

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    Different families of states, which are solutions of the time-dependent free Schr\"odinger equation, are imported from the harmonic oscillator using the Quantum Arnold Transformation introduced in a previous paper. Among them, infinite series of states are given that are normalizable, expand the whole space of solutions, are spatially multi-localized and are eigenstates of a suitably defined number operator. Associated with these states new sets of coherent and squeezed states for the free particle are defined representing traveling, squeezed, multi-localized wave packets. These states are also constructed in higher dimensions, leading to the quantum mechanical version of the Hermite-Gauss and Laguerre-Gauss states of paraxial wave optics. Some applications of these new families of states and procedures to experimentally realize and manipulate them are outlined.Comment: 21 pages, 3 figures. Title changed, content added, references adde

    Tendinitis aquílea en el anciano

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    IntroducciónLas quinolonas son un grupo de agentes antibacterianos sintéticos relacionados estructuralmente con el ácido nalidíxico1. Atendiendo al espectro antibacteriano se clasifican en quinolonas no fluoradas o de primera generación (ácidos nalidíxicos, pipemídico y oxolínico), que tienen un espectro limitado y no alcanzan niveles sistémicos eficaces; fluoroquinolonas de segunda generación (ciprofloxacino, norfloxacino, ofloxacino y perfloxacino), con gran potencia frente a gramnegativos incluidas Pseudomonas, y fluoroquinolonas de tercera generación (levofloxacino y moxifloxacino), con actividad frente a microorganismos grampositivoso y gramnegativos y atípicos. Entre las precauciones que se deben tener en cuenta al prescribir este grupo terapéutico están el evitar la exposición solar prolongada por la fototoxicidad que ocasionan y restringir su uso en niños y adolescentes por la afección del cartílago de crecimiento2.Caso clínicoVarón de 74 años que acudió a nuestra consulta al presentar de forma brusca dificultad a la deambulación por dolor en el pie izquierdo de 48 h de evolución que posteriormente se hizo bilateral. No refería ningún sobreesfuerzo físico ni traumatismo directo y no mejoró tras la toma de antiinflamatorios. En la exploración física no se observaba deformidad, hematoma ni inflamación en ambos tobillos, y destacaba el dolor selectivo en ambos tendons aquíleos, así como la limitación de la flexión dorsal del pie. Al repasar la historia clínica se comprobó que se trataba de un paciente alérgico a las penicilinas y asmático en tratamiento habitual con una inhalación cada 12 h de salmeterol 50 μg/fluticasona 250 μg, y que en ocasiones había necesitado pautas de corticoides por vía oral. Había sido tratado hacía 4 días por una reagudización asmática leve secundaria a una bronquitis aguda, para cuyo tratamiento se aconsejó doblar la dosis de los broncodilatodores y añadir moxifloxacino 400mg/24 h/5 días. Ante la sospecha de una reacción adversa medicamentosa secambió la antibioterapia, y desde entonces el paciente notó una mejoría progresiva de su cuadro clínico. El hecho se notificó al Centro de Farmacovigilancia.Discusión y conclusionesLa tendinitis se considera un efecto adverso poco frecuente del grupo de las quinolonas que puede ocasionar rotura del tendón en el 31% de los casos. El tendón de Aquiles es el más afectado y hasta en un 50% de los casos la afección es bilateral3. La sintomatología aparece dentro de las primeras 2 semanas de tratamiento y cede espontáneamente al retirar la medicación, aunque hasta en un 11% de los pacientes puede persistir 2 meses después. Un número importante de pacientes suele ser anciano y/o recibe tratamiento con corticoides4

    Endolifter, una nueva herramienta para una segura y rápida disección endoscópica submucosa

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    ResumenAntecedentesLa disección endoscópica de la submucosa (DES) tiene una efectividad similar a la cirugía en el tratamiento de las lesiones incipientes. La técnica requiere un alto nivel de destreza técnica. El entrenamiento en modelos biológicos y el perfeccionamiento de accesorios facilita la DES.ObjetivosEl objetivo fue evaluar la utilidad del Endolifter para facilitar la exposición tisular durante la DES en un modelo in vivo porcino. Fue realizado en el laboratorio de cirugía experimental de la Escuela de Medicina de la Facultad de Sao Paulo, Brasil.Material y métodoDiseño experimental en modelo porcino in vivo. Se incluyeron un total de 5 cerdos Yorkshire con un peso de 20-25kg. Las DES se realizaron usando el dispositivo Endolifter. Se empleó un Dual-Knife y el IT-Knife para la disección de la capa submucosa. Todos los procedimientos endoscópicos fueron realizados por un único endoscopista experto.ResultadosSe realizaron un total de 25 DES, con una tasa de éxito técnico del 100%. El tiempo promedio de la disección fue de 12.34min (10.40-14.50min) y el tamaño promedio de las lesiones fue de 2.7cm (2.3-3.2cm). No se presentó hemorragia ni perforaciones durante el procedimiento.ConclusionesEl Endolifter permite realizar DES de manera rápida y eficaz. Es factible, de fácil uso y puede ser empleado por un solo operador.AbstractBackgroundThe effectiveness of endoscopic submucosal dissection (ESD) is similar to that of surgery in the treatment of early lesions. The technique requires a high level of technical skill. Training on biologic models and the mastering of accessories facilitate ESD.AimsThe aim was to evaluate the usefulness of the Endolifter in facilitating tissue exposure during ESD in an in vivo porcine model performed at the experimental surgery laboratory of the School of Medicine at the Universidad de São Paulo in Brazil.Material and methodA study with an experimental design employing an in vivo porcine model was conducted on 5 Yorkshire pigs weighing 20-25kg. ESDs were performed using the Endolifter. Mucosal layer dissection was carried out with a dual knife and IT knife and all the endoscopic procedures were performed by a single expert endoscopist.ResultsA total of 25 ESDs were performed, with a technical success rate of 100%. The mean dissection time was 12.34min (range: 10.40-14.50 min) and the mean lesion size was 2.7cm (range: 2.3-3.2cm). There were no episodes of bleeding or perforations during the procedures.ConclusionsThe Endolifter enables rapid and effective ESDs to be carried out. It is an applicable and easy-to-use device that can be manipulated by a single operator

    Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use

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    Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù

    Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

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    Next-generation neutrinoless double beta decay experiments aim for half-life sensitivities of ~102710^{27} yr, requiring suppressing backgrounds to <1 count/tonne/yr. For this, any extra background rejection handle, beyond excellent energy resolution and the use of extremely radiopure materials, is of utmost importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of NEXT. Previous studies demonstrated a topological background rejection factor of ~5 when reconstructing electron-positron pairs in the 208^{208}Tl 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterr\'aneo de Canfranc, with 72% signal efficiency. This was recently improved through the use of a deep convolutional neural network to yield a background rejection factor of ~10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT TPC. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV ee+e^-e^+ pairs, it leads to a background rejection factor of 27 at 57% signal efficiency.Comment: Submitted to JHE

    NEXT-CRAB-0: A High Pressure Gaseous Xenon Time Projection Chamber with a Direct VUV Camera Based Readout

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    The search for neutrinoless double beta decay (0νββ0\nu\beta\beta) remains one of the most compelling experimental avenues for the discovery in the neutrino sector. Electroluminescent gas-phase time projection chambers are well suited to 0νββ0\nu\beta\beta searches due to their intrinsically precise energy resolution and topological event identification capabilities. Scalability to ton- and multi-ton masses requires readout of large-area electroluminescent regions with fine spatial resolution, low radiogenic backgrounds, and a scalable data acquisition system. This paper presents a detector prototype that records event topology in an electroluminescent xenon gas TPC via VUV image-intensified cameras. This enables an extendable readout of large tracking planes with commercial devices that reside almost entirely outside of the active medium.Following further development in intermediate scale demonstrators, this technique may represent a novel and enlargeable method for topological event imaging in 0νββ0\nu\beta\beta.Comment: 32 Pages, 22 figure

    Ba+2 ion trapping using organic submonolayer for ultra-low background neutrinoless double beta detector

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    If neutrinos are their own antiparticles the otherwise-forbidden nuclear reaction known as neutrinoless double beta decay can occur. The very long lifetime expected for these exceptional events makes its detection a daunting task. In order to conduct an almost background-free experiment, the NEXT collaboration is investigating novel synthetic molecular sensors that may capture the Ba dication produced in the decay of certain Xe isotopes in a high-pressure gas experiment. The use of such molecular detectors immobilized on surfaces must be explored in the ultra-dry environment of a xenon gas chamber. Here, using a combination of highly sensitive surface science techniques in ultra-high vacuum, we demonstrate the possibility of employing the so-called Fluorescent Bicolor Indicator as the molecular component of the sensor. We unravel the ion capture process for these molecular indicators immobilized on a surface and explain the origin of the emission fluorescence shift associated to the ion trapping

    Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

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    Next-generation neutrinoless double beta decay experiments aim for half-life sensitivities of similar to 10(27) yr, requiring suppressing backgrounds to < 1 count/tonne/yr. For this, any extra background rejection handle, beyond excellent energy resolution and the use of extremely radiopure materials, is of utmost importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of NEXT. Previous studies demonstrated a topological background rejection factor of 5 when reconstructing electron-positron pairs in the Tl-208 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterraneo de Canfranc, with 72% signal efficiency. This was recently improved through the use of a deep convolutional neural network to yield a background rejection factor of similar to 10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT TPC. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV e(-)e(+) pairs, it leads to a background rejection factor of 27 at 57% signal efficiency.The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Research Council (ERC) under the Advanced Grant 339787-NEXT; the European Union's Framework Programme for Research and Innovation Horizon 2020 (2014-2020) under the Grant Agreements No. 674896, 690575 and 740055; the Ministerio de Economia y Competitividad and the Ministerio de Ciencia, Innovacion y Universidades of Spain under grants FIS2014-53371-C04, RTI2018-095979, the Severo Ochoa Program grants SEV-2014-0398 and CEX2018-000867-S, and the Maria de Maeztu Program MDM-2016-0692; the Generalitat Valenciana under grants PROMETEO/2016/120 and SEJI/2017/011; the Portuguese FCT under project PTDC/FIS-NUC/2525/2014 and under projects UID/04559/2020 to fund the activities of LIBPhys-UC; the U.S. Department of Energy under contracts No. DE-AC02-06CH11357 (Argonne National Laboratory), DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), DE-FG02-13ER42020 (Texas A&M) and DE-SC0019223/DE-SC0019054 (University of Texas at Arlington); the University of Texas at Arlington (U.S.A.); and the Pazy Foundation (Israel) under grants 877040 and 877041. DGD acknowledges Ramon y Cajal program (Spain) under contract number RYC-2015-18820. JM-A acknowledges support from Fundacion Bancaria "la Caixa" (ID 100010434), grant code LCF/BQ/PI19/11690012. AS acknowledges support from the Kreitman School of Advanced Graduate Studies at Ben-Gurion University. Documen

    Boosting background suppression in the NEXT experiment through Richardson-Lucy deconvolution

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    Next-generation neutrinoless double beta decay experiments aim for half-life sensitivities of ~ 1027 yr, requiring suppressing backgrounds to &lt; 1 count/tonne/yr. For this, any extra background rejection handle, beyond excellent energy resolution and the use of extremely radiopure materials, is of utmost importance. The NEXT experiment exploits differences in the spatial ionization patterns of double beta decay and single-electron events to discriminate signal from background. While the former display two Bragg peak dense ionization regions at the opposite ends of the track, the latter typically have only one such feature. Thus, comparing the energies at the track extremes provides an additional rejection tool. The unique combination of the topology-based background discrimination and excellent energy resolution (1% FWHM at the Q-value of the decay) is the distinguishing feature of NEXT. Previous studies demonstrated a topological background rejection factor of ~ 5 when reconstructing electron-positron pairs in the 208Tl 1.6 MeV double escape peak (with Compton events as background), recorded in the NEXT-White demonstrator at the Laboratorio Subterráneo de Canfranc, with 72% signal efficiency. This was recently improved through the use of a deep convolutional neural network to yield a background rejection factor of ~ 10 with 65% signal efficiency. Here, we present a new reconstruction method, based on the Richardson-Lucy deconvolution algorithm, which allows reversing the blurring induced by electron diffusion and electroluminescence light production in the NEXT TPC. The new method yields highly refined 3D images of reconstructed events, and, as a result, significantly improves the topological background discrimination. When applied to real-data 1.6 MeV e-e+ pairs, it leads to a background rejection factor of 27 at 57% signal efficiency. [Figure not available: see fulltext.]. © 2021, The Author(s)
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