3,321 research outputs found

    Desarrollo de modelo para mejorar proceso de exportaciones en empresa fabricante de empaque flexible

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    En este trabajo se hace un análisis de los procesos de exportación de una empresa dedicada a la fabricación de empaques flexibles, elaborados a partir de películas plásticas de polipropileno (OPP), polietileno (PE) y poliéster (PET). El objetivo es proponer acciones para la solución de los problemas de calidad generados debido a los requerimientos de un cliente de Estados Unidos

    Exciting polaritons with quantum light

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    We discuss the excitation of polaritons---strongly-coupled states of light and matter---by quantum light, instead of the usual laser or thermal excitation. As one illustration of the new horizons thus opened, we introduce Mollow spectroscopy, a theoretical concept for a spectroscopic technique that consists in scanning the output of resonance fluorescence onto an optical target, from which weak nonlinearities can be read with high precision even in strongly dissipative environments.Comment: 5 pages, 3 figure

    Emitters of NN-photon bundles

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    We propose a scheme based on the coherent excitation of a two-level system in a cavity to generate an ultrabright CW and focused source of quantum light that comes in groups (bundles) of NN photons, for an integer NN tunable with the frequency of the exciting laser. We define a new quantity, the \emph{purity} of NN-photon emission, to describe the percentage of photons emitted in bundles, thus bypassing the limitations of Glauber correlation functions. We focus on the case 1N31\le N\le3 and show that close to 100% of two-photon emission and 90% of three-photon emission is within reach of state of the art cavity QED samples. The statistics of the bundles emission shows that various regimes---from NN-photon lasing to NN-photon guns---can be realized. This is evidenced through generalized correlation functions that extend the standard definitions to the multi-photon level.Comment: Introduce the n-th order N-photon correlation functions. Reorganized to emphasize the N-photon emitter, now extended to the antibunching regime, rather than only coherent emission as previsoul

    Searching for novel genes and pseudogenes in the human Y chromosome based on ancestral coding signals

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    Motivation: Human Y chromosome has several features that contribute to an extreme variation due to the lack of a homologous partner for crossing over, high rate of sequence amplification and low evolutionary pressure [1]. For these reasons, we think that the Y chromosome could be a perfect candidate in order to discover new coding and fossil regions such as pseudogenes.Genome finding is one of the greatest hits in modern biology. However, in silico identification of small and complex coding sequences is still challenging. Jiménez et al [2] developed AnAblast, a computer tool which has been successful in uncovering new genes, as well as fossil-coding sequences. This program generates profiles of accumulated alignments of conserved coding signals using a low-stringency BLAST strategy [2]. Methods: We have used AnAblast to localizate new coding regions in the chromosome Y. After that, AnAblast-generated profiles were introduced into a genome browser, along with other informative data such as repeats and RNA expression data. The candidate's list obtained was complemented by careful BLAST, InterPro and peaks analysis. Moreover, we performed a search on the tool Genome Data Viewer (GDV) to check each result.Results: We have been able to identify some chromosome Y regions that fulfill different requirements: (1) regions without previous annotations as pseudogenes, genes or non-coding regions (Ensembl track); (2) regions without previous annotations as interspersed repeats and low complexity (RepeatMasker track); and (3) regions with expression profiles (RNA-seq of testis).The best candidate to be a new coding region was localized at Y:9912876-9919657 (-). Blast and InterPro analysis indicated similarity with serine-proteases which are found in rodents and another organism such as Rousettus aegyptiacus (Egyptian fruit bat). After the search on GDV, we observed that only the first bat´s exon was not found in our candidate. In spite of this, we found a methionine codon in our candidate (more specifically in the first exon). Furthermore, the Y chromosome has a 5´-truncated copy of this region.Conclusions: We have found some chromosome Y regions which could be new coding genes or pseudogenes. Thus, this in silico research provides a powerful protocol to search novel genes and fossil regions in the whole human genome. Although we added several RNA-seq tracks that showed the expression of these regions, clinical trials should be performed to verify our candidates

    Attention to Monocular Images Bias Binocular Rivalry

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    When monocular images cannot be fused, perception alternates between the two (or more) possible images. This phenomenon, binocular rivalry (BR), is driven by the physical properties of the stimuli (size, contrast, spatial frequency, etc.) but it can also be modulated by attention to features of one of the rival stimuli (Chong et al., 2005; Dieter et al., 2016) and by attentional demands independent of the BR assessment (Paffen et al., 2008). Instead of the perceptually demanding tasks previously used to bias BR, we designed a simple counting task. We monocularly presented a number of trials (around 10 min) with a set of symbols and asked participants to count them. We found that after this task, dominance durations decreased for the unattended channel, and did not change for the attended channel. The results parallel those of Paffen et al. (2008) and square nicely with Levelt’s second proposition, suggesting that the counting task effectively increased the sensibility of one channel which led to increased strength of the images presented to that channel. Alternatively, the results could be explained assuming that the non-attended channel was inhibited during the counting task, and the inhibition was carried over to the BR task

    Small molecules targeting glycogen synthase kinase 3 as potential drug candidates for the treatment of retinitis pigmentosa

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    6 p.-5 fig.Retinitis pigmentosa (RP) is an inherited retinal dystrophy that courses with progressive degeneration of retinal tissue and loss of vision. Currently, RP is an unpreventable, incurable condition. We propose glycogen synthase kinase 3 (GSK-3) inhibitors as potential leads for retinal cell neuroprotection, since the retina is also a part of the central nervous system and GSK-3 inhibitors are potent neuroprotectant agents. Using a chemical genetic approach, diverse small molecules with different potency and binding mode to GSK-3 have been used to validate and confirm GSK-3 as a pharmacological target for RP. Moreover, this medicinal chemistry approach has provided new leads for the future disease-modifying treatment of RP.This work has been partially funded by the Spanish MINECO grants (SAF2012-37979-C03-01 to AM and SAF2013-41059-R to EJdlR).Peer reviewe

    N2 year in review

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    Stellar Populations in type Ia supernova host galaxies at intermediate-high redshift: Star formation and metallicity enrichment histories

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    We present a summary of our project that studies galaxies hosting type Ia supernova (SN Ia) at different redshifts. We present Gran Telescopio de Canarias (GTC) optical spectroscopy of six SN Ia host galaxies at redshift z0.40.5z\sim 0.4-0.5. They are joined to a set of SN Ia host galaxies at intermediate-high redshift, which include galaxies from surveys SDSS and COSMOS. The final sample, after a selection of galaxy spectra in terms of signal-to-noise and other characteristics, consists of 680 galaxies with redshift in the range 0.04<z<10.04 < z < 1. We perform an inverse stellar population synthesis with the code {\sc fado} to estimate the star formation and enrichment histories of this set of galaxies, simultaneously obtaining their mean stellar age and metallicity and stellar mass. After analysing the correlations among these characteristics, we look for possible dependencies of the Hubble diagram residuals and supernova features (luminosity, color and strength parameter) on these stellar parameters. We find that the Hubble residuals show a clear dependence on the stellar metallicity weighted by mass with a slope of -0.061\,mag\,dex1^{-1}, when represented in logarithmic scale, logZM/Z\log{ \langle Z_{M}/Z_{\odot}\rangle }. This result supports our previous findings obtained from gas oxygen abundances for local and SDSS-survey galaxies. Comparing with other works from the literature that also use the stellar metallicity, we find a similar value, but with more precision and a better significance (2.08 vs \sim 1.1), due to the higher number of objects and wider range of redshift of our sample.Comment: 21 pages, 19 figures, accepted for publication in Monthly Notices of the Royal Astronomical Societ

    Magnetovolume and magnetocaloric effects in Er2Fe17

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    Combining different experimental techniques, investigations in hexagonal P63/mmc Er2Fe17 show remarkable magnetovolume anomalies below the Curie temperature, TC. The spontaneous magnetostriction reaches 1.6×10−2 at 5 K and falls to zero well above TC, owing to short-range magnetic correlations. Moreover, Er2Fe17 exhibits direct and inverse magnetocaloric effects (MCE) with moderate isothermal magnetic entropy ΔSM, and diabatic temperature ΔTad changes [ΔSM∼−4.7 J(kgK)−1 and ΔTad∼2.5 K near the TC, and ΔSM∼1.3 J(kgK)−1 and ΔTad∼−0.6 K at 40 K for ΔH=80 kOe, respectively, determined from magnetization measurements]. The existence of an inverse MCE seems to be related to a crystalline electric field-level crossover in the Er sublattice and the ferrimagnetic arrangement between the magnetic moments of the Er and Fe sublattice. The main trends found experimentally for the temperature dependence of ΔSM and ΔTad as well as for the atomic magnetic moments are qualitatively well described considering a mean-field Hamiltonian that incorporates both crystalline electric field and exchange interactions. ΔSM(T) and ΔTad(T) curves are essentially zero at ∼150 K, the temperature where the transition from direct to inverse MCE occurs. A possible interplay between the MCE and the magnetovolume anomalies is also discussed.Financial support from Spanish MICINN (MAT2011-27573-C04-02) and from the Basque Government (IT-347- 07) is acknowledged. J.L.S.Ll. acknowledges the support received from CONACYT, Mexico, under the project CB2010-01-156932, and Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología (LINAN, IPICyT). J.A.R.V. acknowledges the support from the research project MAT2007-61621. We thank ILL and CRG-D1B for allocating neutron beamtime, and ESRF for synchrotron beamtime. The SCTs at the University of Oviedo and the technical support received from M.Sc. G. J. Labrada-Delgado and B. A. Rivera-Escoto (DMA, IPICyT) are also acknowledged
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