3,914 research outputs found

    Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer

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    We present a structurally flexible copper–iodide–pyridine-based coordination polymer showing drastic variations in its electrical conductivity driven by temperature and sorption of acetic acid molecules. The dramatic effect on the electrical conductivity enables the fabrication of a simple and robust device for gas detection. X-ray diffraction studies and DFT calculations allow the rationalisation of these observations.We are thankful for support from MICINN (MAT2013-46753-C2-1-P, MAT2013-46502-C2-1/2-P and CTQ2011-26507), Eusko Jaurlaritza (S-PE13UN016) and Generalitat Valenciana PrometeoII/2014/076

    U B V R I Photometry of Stellar Structures throughout the Disk of the Barred Galaxy NGC 3367

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    We report new detailed surface U, B, V, R, and I photometry of 81 stellar structures in the disk of the barred galaxy NGC 3367. The images show many different structures indicating that star formation is going on in the most part of the disk. NGC 3367 is known to have a very high concentration of molecular gas distribution in the central regions of the galaxy and bipolar synchrotron emission from the nucleus with two lobes (at 6 kpc) forming a triple structure similar to a radio galaxy. We have determined the U, B, V, R, and I magnitudes and U - B, B - V, U - V, and V - I colors for the central region (nucleus), a region which includes supernovae 2003 AA, and 79 star associations throughout NGC 3367. Estimation of ages of star associations is very difficult due to several factors, among them: filling factor, metallicity, spatial distribution of each structure and the fact that we estimated the magnitudes with a circular aperture of 16 pixels in diameter, equivalent to 6.81.46''.8\sim1.4 kpc. However, if the colors derived for NGC 3367 were similar to the colors expected of star clusters with theoretical evolutionary star tracks developed for the LMC and had a similar metallicity, NGC 3367 show 51 percent of the observed structures with age type SWB I (few tens of Myrs), with seven sources outside the bright surface brightness visible disk of NGC 3367.Comment: Accepted for publication (abr 2007) in The Astronomical Journal (July 2007 issue

    Evaluación de la viabilidad de bacterias ácido lácticas en yogurt porcesado mediante diferentes tecnologías de secado.

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    Las tendencias al desarrollo de nuevas tecnologías para la obtención de productos deshidratados se ha incrementado en los últimos años, sin embargo, las aplicaciones de las mismas suelen ser limitadas debido a los efectos negativos en algunas características físicas, químicas y sensoriales del producto en cuestión. El yogurt es un alimento consumido alrededor del mundo, por ser fuente de probióticos. Uno de los retos más importantes en la obtención de un yogurt deshidratado es la preservación de las características probióticas, por los beneficios que aporta. En esta investigación se evaluó la viabilidad de bacterias ácido lácticas (BAL) en yogurt deshidratado mediante diferentes tecnologías. El yogurt fue adicionado con agentes espesantes, inulina y albumina de huevo en diferentes concentraciones para posteriormente secarse mediante dos métodos a diferentes temperaturas. El método convencional evidenció pérdida significativa de BAL con respecto al control, mientras que el método diseñado con algunas características controladas de presión y temperatura presentó una recuperación aproximada del 100% manteniendo la concentración de BAL requeridas según la NOM-243-SSA1-2010, Productos y servicios. Leche, fórmula láctea, producto lácteo combinado y derivados lácteos. Disposiciones y especificaciones sanitarias. Al determinar la calidad sanitaria del producto se encontró que cumple con los requerimientos sanitarios mencionados en la misma

    Unbounded violation of tripartite Bell inequalities

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    We prove that there are tripartite quantum states (constructed from random unitaries) that can lead to arbitrarily large violations of Bell inequalities for dichotomic observables. As a consequence these states can withstand an arbitrary amount of white noise before they admit a description within a local hidden variable model. This is in sharp contrast with the bipartite case, where all violations are bounded by Grothendieck's constant. We will discuss the possibility of determining the Hilbert space dimension from the obtained violation and comment on implications for communication complexity theory. Moreover, we show that the violation obtained from generalized GHZ states is always bounded so that, in contrast to many other contexts, GHZ states do in this case not lead to extremal quantum correlations. The results are based on tools from the theories of operator spaces and tensor norms which we exploit to prove the existence of bounded but not completely bounded trilinear forms from commutative C*-algebras.Comment: Substantial changes in the presentation to make the paper more accessible for a non-specialized reade

    Radiation Campaign of HPK Prototype LGAD sensors for the High-Granularity Timing Detector (HGTD)

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    We report on the results of a radiation campaign with neutrons and protons of Low Gain Avalanche Detectors (LGAD) produced by Hamamatsu (HPK) as prototypes for the High-Granularity Timing Detector (HGTD) in ATLAS. Sensors with an active thickness of 50~μ\mum were irradiated in steps of roughly 2×\times up to a fluence of 3×1015 neqcm23\times10^{15}~\mathrm{n_{eq}cm^{-2}}. As a function of the fluence, the collected charge and time resolution of the irradiated sensors will be reported for operation at 30-30^{\circ}

    Constraining the pˉ/p\bar{p}/p Ratio in TeV Cosmic Rays with Observations of the Moon Shadow by HAWC

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    An indirect measurement of the antiproton flux in cosmic rays is possible as the particles undergo deflection by the geomagnetic field. This effect can be measured by studying the deficit in the flux, or shadow, created by the Moon as it absorbs cosmic rays that are headed towards the Earth. The shadow is displaced from the actual position of the Moon due to geomagnetic deflection, which is a function of the energy and charge of the cosmic rays. The displacement provides a natural tool for momentum/charge discrimination that can be used to study the composition of cosmic rays. Using 33 months of data comprising more than 80 billion cosmic rays measured by the High Altitude Water Cherenkov (HAWC) observatory, we have analyzed the Moon shadow to search for TeV antiprotons in cosmic rays. We present our first upper limits on the pˉ/p\bar{p}/p fraction, which in the absence of any direct measurements, provide the tightest available constraints of 1%\sim1\% on the antiproton fraction for energies between 1 and 10 TeV.Comment: 10 pages, 5 figures. Accepted by Physical Review

    Holocene geochemical footprint from Semiarid alpine wetlands in southern Spain

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    Here we provide the geochemical dataset that our research group has collected after 10 years of investigation in the Sierra Nevada National Park in southern Spain. These data come from Holocene sedimentary records from four alpine sites (ranging from ∼2500 to ∼3000 masl): two peatlands and two shallow lakes. Different kinds of organic and inorganic analyses have been conducted. The organic matter in the bulk sediment was characterised using elemental measurements and isotope-ratio mass spectrometry (EA-IRMS). Leaf waxes in the sediment were investigated by means of chromatography with flame-ionization detection and mass spectrometry (GC-FID, GC-MS). Major, minor and trace elements of the sediments were analysed with atomic absorption (AAS), inductively coupled plasma mass spectrometry (ICP-MS), as well as X-ray scanning fluorescence. These data can be reused by environmental researchers and soil and land managers of the Sierra Nevada National Park and similar regions to identify the effect of natural climate change, overprinted by human impact, as well as to project new management policies in similar protected areas.Universidad de Granada. Departamento de Estratigrafía y PaleontologíaJunta de Andalucía: Grupos de investigación RNM190 y RNM309Junta de Andalucía: Proyecto P11-RNM-7332España, Ministerio de Economía y Competitividad: Proyecto CGL2013-47038-RRamón y Cajal Fellowship: RYC-2015-18966Small Research Grant by the Carnegie Trust for the Universities of ScotlandMarie Curie Intra-European Fellowship of the 7th Framework Programme for Research, Technological Development and Demonstration of the European Commission: NAOSIPUK. Grant Number: PIEF-GA-2012-62302

    All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

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    We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of 2.49±0.01-2.49\pm0.01 prior to a break at (45.7±0.1(45.7\pm0.1) TeV, followed by an index of 2.71±0.01-2.71\pm0.01. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review
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