4,749 research outputs found

    Localised projective measurement of a relativistic quantum field in non-inertial frames

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    We propose a scheme to study the effect of motion on measurements of a quantum field carried out by a finite-size detector. We introduce a model of projective detection of a localised field mode in an arbitrary reference frame. We apply it to extract vacuum entanglement by a pair of counter-accelerating detectors and to estimate the Unruh temperature of a single accelerated detector. The introduced method allows us to directly relate the observed effects with the instantaneous proper acceleration of the detector.Comment: 5 pages, 2 figures. v2 Significant increase in the detail level regarding the motivation of the detector mode

    Colchicine therapy in acute coronary syndrome patients acts on caspase-1 to suppress NLRP3 inflammasome monocyte activation

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    Inflammasome activation, with subsequent release of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18, has recently been implicated in atherosclerosis-associated inflammation. This study aims to assess in acute coronary syndrome (ACS) patients (1) inflammasome activation in circulating monocytes and (2) whether short-term oral colchicine, a recognized anti-inflammatory agent that has been shown to be cardio-protective in clinical studies, might acutely suppress inflammasome-dependent inflammation. ACS patients (n=21) were randomized to oral colchicine (1 mg followed by 0.5 mg 1 h later) or no treatment, and compared with untreated healthy controls (n=9). Peripheral venous blood was sampled pre- (day 1) and 24 h post- (day 2) treatment. Monocytes were cultured and stimulated with ATP. Analysis of key inflammasome markers was performed by ELISA. IL-1β secretion increased by 580.4% (P<0.01) in ACS patients compared with controls but only with ATP stimulation. Untreated ACS patients secreted significantly higher levels of IL-18 compared with healthy controls independent of ATP stimulation (P<0.05). Colchicine treatment in ACS patients markedly reduced intracellular and secreted levels of IL-1β compared with pre-treatment levels (P<0.05 for both), as well as significantly reducing pro-caspase-1 mRNA levels by 57.7% and secreted caspase-1 protein levels by 30.2% compared with untreated patients (P<0.05 for both). Monocytes from ACS patients are ‘primed’ to secrete inflammasome-related cytokines and short-term colchicine acutely and markedly suppresses monocyte caspase-1 activity, thereby reducing monocyte secretion of IL-1β

    Comportamiento frente a la corrosión inducida por cloruros de armaduras de nuevos aceros inoxidables con bajo contenido en níquel

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    La utilización de armaduras de acero inoxidable, de los tipos austeníticos y dúplex, con el objetivo de prolongar la vida útil de las estructuras de hormigón, es una alternativa que está recibiendo cada vez más consideración. Los aceros inoxidables son aleaciones fundamentalmente de cromo y níquel, con muy alta resistencia a la corrosión, especialmente por cloruros. El elevado coste del níquel y sus grandes fluctuaciones en el mercado, han favorecido la aparición de nuevos aceros inoxidables con bajo contenido en dicha aleación y, por lo tanto, más económicos, que sin embargo presentan una resistencia a la corrosión similar a los tradicionales. En este trabajo se ha evaluado la resistencia a la corrosión por cloruros de dos nuevos aceros inoxidables de bajo contenido en níquel. Uno de los aceros es austenítico, de producción en forma de chapa, y el otro dúplex, que se comercializa como barra corrugada. La resistencia a la corrosión se ha evaluado, respectivamente, mediante ensayos electroquímicos de dichos aceros embebidos en solución simulada de poros de hormigón y en probetas de mortero contaminados con diferentes cuantías de cloruros. Los resultados de los ensayos se han comparado con los del acero austenítico tradicional AISI 304 y del acero al carbono B500SD

    Cross-species infectivity of H3N8 influenza virus in an experimental infection in swine

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    Avian influenza A viruses have gained increasing attention due to their ability to cross the species barrier and cause severe disease in humans and other mammal species as pigs. H3 and particularly H3N8 viruses, are highly adaptive since they are found in multiple avian and mammal hosts. H3N8 viruses have not been isolated yet from humans; however, a recent report showed that equine influenza A viruses (IAVs) can be isolated from pigs, although an established infection has not been observed thus far in this host. To gain insight into the possibility of H3N8 avian IAVs to cross the species barrier into pigs, in vitro experiments and an experimental infection in pigs with four H3N8 viruses from different origins (equine, canine, avian, and seal) were performed. As a positive control, an H3N2 swine influenza virus A was used. Although equine and canine viruses hardly replicated in the respiratory systems of pigs, avian and seal viruses replicated substantially and caused detectable lesions in inoculated pigs without previous adaptation. Interestingly, antibodies against hemagglutinin could not be detected after infection by hemagglutination inhibition (HAI) test with avian and seal viruses. This phenomenon was observed not only in pigs but also in mice immunized with the same virus strains. Our data indicated that H3N8 IAVs from wild aquatic birds have the potential to cross the species barrier and establish successful infections in pigs that might spread unnoticed using the HAI test as diagnostic tool.We thank Jaime Maldonado and HIPRA (Spain) for the A/Swine/Spain/ 54008/2004 (H3N2) strain, Edward J. Dubovi and Cornell University for the A/Canine/NY/105447/08 (H3N8) IAV strain, T. M. Chambers and the University of Kentucky for the A/Equine/OH/1/03 (H3N8) IAV strain, and Hon Ip and the U.S. Geological Survey National Wildlife Health Center for the A/American black duck/Maine/44411-532/2008 (H3N8) and the A/Harbor Seal/New Hampshire/179629/2011 (H3N8) IAV strains. We thank Sergio López, David Solanes, Francisco X. Abad, Jordi Alberola, Jaume Martorell, and Eduard J. Cunilleras for help in providing different samples and during the experimental infections, as well as the personnel in Cat3 laboratories and the animal house. We thank Adolfo García-Sastre for providing materials and for support as the principal investigator of the NIAID-funded Center for Research in Influenza Pathogenesis (HHSN266200700010C). The research leading to these results received funding from the European Community’s Seventh Framework Programme (FP7, 2007-2013), the Research Infrastructures Action under grant FP7-228393 (a NADIR project), and projects AGL2010-22200-C02-01 and AGL2007-60274 of the Spanish Ministry of Science and Innovation

    Optimization of micro single dielectric barrier discharge plasma actuator models based on experimental velocity and body force fields

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    Recently, the Micro Single Dielectric Barrier Discharge Plasma Actuator has become attractive for application in aeronautics and micropopulsion thrusters. The present work carried out a preliminary characterization of such device, acting on initially quiescent air by experimental and numerical approaches. Sinusoidal voltage excitation with amplitude up to 7 kV and frequency up to 2.5 kHz was applied. The induced flow was investigated by particle image velocimetry and the measured velocity fields were used to estimate experimentally the time-averaged induced body force distributions by a differential method. Plasma induced forces were modeled by following three different approaches, later implemented as a source term in the Navier-Stokes equations for the fluid flow simulations. Potentialities, advantages and disadvantages of the considered force modeling methods were investigated. Quantitative comparison of the experimental and numerical induced force, as well as of the velocity fields, allowed establishing which model best predicted the actuator effects. The algebraic Dual Potential Model provided a good agreement between experimental and simulated results, in terms of flow velocities and thickness of the induced wall-jet. The downstream decay of the wall-jet velocity, experimentally observed, was also successfully predicted. A maximum induced velocity of ≈2 m/s was obtained and a jet thickness of ≈3 mm

    Linearizing Toda and SVD flows on large phase spaces of matrices with real spectrum

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    We consider different phase spaces for the Toda flows and the less familiar SVD flows. For the Toda flow, we handle symmetric and non-symmetric matrices with real simple eigenvalues, possibly with a given profile. Profiles encode, for example, band matrices and Hessenberg matrices. For the SVD flow, we assume simplicity of the singular values. In all cases, an open cover is constructed, as are corresponding charts to Euclidean space. The charts linearize the flows, converting it into a linear differential system with constant coefficients and diagonal matrix. A variant construction transform the flows into uniform straight line motion. Since limit points belong to the phase space, asymptotic behavior becomes a local issue. The constructions rely only on basic facts of linear algebra, making no use of symplectic geometry.Comment: 25 pages, 2 figure

    Estrategias para impulsar la sustentabilidad social en la zona metropolitana de Guadalajara a través de la colaboración entre arquitectura social y arquitectura colectiva. Caso de estudio: Parque González Gallo

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    Este trabajo presenta estrategias elaboradas a partir de elementos participatorios como solución a problemáticas de los espacios públicos en la Zona Metropolitana de Guadalajara (ZMG). La finalidad del trabajo conjugó los conceptos de Arquitectura Social y Arquitectura Colectiva en la mejora del tejido social para fortalecer de esta manera la sustentabilidad social en la construcción del espacio público a través de la colaboración de los grupos sociales, culturales, actores principales, administradores y profesionales de diferentes áreas, que aporten a una construcción de relaciones; para ello, se toma como caso de estudio el Parque González Gallo dentro de la ZMG. La metodología seleccionada para este trabajo parte de una postura hermenéutica interpretativa, así como métodos y técnicas cuantitativas, cualitativas y participativas. El trabajo de campo se realizó de enero de 2015 a mayo de 2016. Dentro de los hallazgos encontrados, se comprobó que en el Parque González Gallo existen grupos de usuarios y actores que tienen apropiación del sitio, existe una imagen, identidad y significado que estos individuos han formado en torno al espacio público y por tanto una evidencia de la construcción social del hábitat. También apareció evidencia de la sustentabilidad del espacio público gracias a esta participación y apropiación activa en el micro-territorio de estudio.Consejo Nacional de Ciencia y Tecnologí

    Microbial iron management mechanisms in extremely acidic environments: comparative genomics evidence for diversity and versatility

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    <p>Abstract</p> <p>Background</p> <p>Iron is an essential nutrient but can be toxic at high intracellular concentrations and organisms have evolved tightly regulated mechanisms for iron uptake and homeostasis. Information on iron management mechanisms is available for organisms living at circumneutral pH. However, very little is known about how acidophilic bacteria, especially those used for industrial copper bioleaching, cope with environmental iron loads that can be 10<sup>18 </sup>times the concentration found in pH neutral environments. This study was motivated by the need to fill this lacuna in knowledge. An understanding of how microorganisms thrive in acidic ecosystems with high iron loads requires a comprehensive investigation of the strategies to acquire iron and to coordinate this acquisition with utilization, storage and oxidation of iron through metal responsive regulation. <it>In silico </it>prediction of iron management genes and Fur regulation was carried out for three Acidithiobacilli: <it>Acidithiobacillus ferrooxidans </it>(iron and sulfur oxidizer) <it>A. thiooxidans </it>and <it>A. caldus </it>(sulfur oxidizers) that can live between pH 1 and pH 5 and for three strict iron oxidizers of the <it>Leptospirillum </it>genus that live at pH 1 or below.</p> <p>Results</p> <p>Acidithiobacilli have predicted FeoB-like Fe(II) and Nramp-like Fe(II)-Mn(II) transporters. They also have 14 different TonB dependent ferri-siderophore transporters of diverse siderophore affinity, although they do not produce classical siderophores. Instead they have predicted novel mechanisms for dicitrate synthesis and possibly also for phosphate-chelation mediated iron uptake. It is hypothesized that the unexpectedly large number and diversity of Fe(III)-uptake systems confers versatility to this group of acidophiles, especially in higher pH environments (pH 4–5) where soluble iron may not be abundant. In contrast, Leptospirilla have only a FtrI-Fet3P-like permease and three TonB dependent ferri-dicitrate siderophore systems. This paucity of iron uptake systems could reflect their obligatory occupation of extremely low pH environments where high concentrations of soluble iron may always be available and were oxidized sulfur species might not compromise iron speciation dynamics. Presence of bacterioferritin in the Acidithiobacilli, polyphosphate accumulation functions and variants of FieF-like diffusion facilitators in both Acidithiobacilli and Leptospirilla, indicate that they may remove or store iron under conditions of variable availability. In addition, the Fe(II)-oxidizing capacity of both <it>A. ferrooxidans </it>and Leptospirilla could itself be a way to evade iron stress imposed by readily available Fe(II) ions at low pH. Fur regulatory sites have been predicted for a number of gene clusters including iron related and non-iron related functions in both the Acidithiobacilli and Leptospirilla, laying the foundation for the future discovery of iron regulated and iron-phosphate coordinated regulatory control circuits.</p> <p>Conclusion</p> <p><it>In silico </it>analyses of the genomes of acidophilic bacteria are beginning to tease apart the mechanisms that mediate iron uptake and homeostasis in low pH environments. Initial models pinpoint significant differences in abundance and diversity of iron management mechanisms between Leptospirilla and Acidithiobacilli, and begin to reveal how these two groups respond to iron cycling and iron fluctuations in naturally acidic environments and in industrial operations. Niche partitions and ecological successions between acidophilic microorganisms may be partially explained by these observed differences. Models derived from these analyses pave the way for improved hypothesis testing and well directed experimental investigation. In addition, aspects of these models should challenge investigators to evaluate alternative iron management strategies in non-acidophilic model organisms.</p

    Potential of Supercritical Carbon Dioxide Power Cycles to Reduce the Levelised Cost of Electricity of Contemporary Concentrated Solar Power Plants

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    This paper provides an assessment of the expected Levelised Cost of Electricity enabled by Concentrated Solar Power plants based on Supercritical Carbon Dioxide (sCO2) technology. A global approach is presented, relying on previous results by the authors in order to ascertain whether these innovative power cycles have the potential to achieve the very low costs of electricity reported in the literature. From a previous thermodynamic analysis of sCO2 cycles, three layouts are shortlisted and their installation costs are compared prior to assessing the corresponding cost of electricity. Amongst them, the Transcritical layout is then discarded due to the virtually impossible implementation in locations with high ambient temperature. The remaining layouts, Allam and Partial Cooling are then modelled and their Levelised Cost of Electricity is calculated for a number of cases and two different locations in North America. Each case is characterised by a different dispatch control scheme and set of financial assumptions. A Concentrated Solar Power plant based on steam turbine technology is also added to the assessment for the sake of comparison. The analysis yields electricity costs varying in the range from 8 to over 11 g/kWh, which is near but definitely not below the 6 g/kWh target set forth by different administrations. Nevertheless, in spite of the results, a review of the conservative assumptions adopted in the analysis suggests that attaining costs substantially lower than this is very likely. In other words, the results presented in this paper can be taken as an upper limit of the economic performance attainable by Supercritical Carbon Dioxide in Concentrated Solar Power applications.Unión Europea (Programa Horizonte 2020) 81498

    A Petal of the Sunflower: Photometry of the Stellar Tidal Stream in the Halo of Messier 63 (NGC 5055)

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    We present surface photometry of a very faint, giant arc feature in the halo of the nearby spiral galaxy NGC 5055 (M63) that is consistent with being a part of a stellar stream resulting from the disruption of a dwarf satellite galaxy. This faint feature was first detected in early photographic studies by van der Kruit (1979); more recently by Mart\'inez-Delgado et al. (2010) and as presented in this work, the loop has been realized to be the result of a recent minor merger through evidence obtained by deep images taken with a telescope of only 0.16 m aperture. The stellar stream is confirmed in additional images taken with the 0.5 m of the BlackBird Remote Observatory and the 0.8 m of the McDonald Observatory. This low surface brightness structure around the disk of the galaxy extends ~29 kpc from its center, with a projected width of 3.3 kpc. The stream's morphology is consistent with that of the visible part of a "great-circle" stellar stream originating from the accretion of a ~10^8 M_sun dwarf satellite in the last few Gyr. The progenitor satellite's current position and fate are not conclusive from our data. The color of the stream's stars is consistent with Local Group dwarfs and is similar to the outer regions of M63's disk and stellar halo. We detect other low surface brightness "plumes"; some of these may be extended spiral features related to the galaxy's complex spiral structure and others may be tidal debris associated with the disruption of the galaxy's outer stellar disk as a result of the accretion event. We differentiate between features related to the tidal stream and faint, blue features in the outskirts of the galaxy's disk previously detected by the GALEX satellite. With its highly warped HI gaseous disk (~20 deg), M63 represents one of several examples of an isolated spiral galaxy with a warped disk showing strong evidence of an ongoing minor merger.Comment: 16 pages, 10 figures, 3 tables, Accepted for publication in The Astronomical Journa
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