1,638 research outputs found

    Tunable entanglement distillation of spatially correlated down-converted photons

    Full text link
    We report on a new technique for entanglement distillation of the bipartite continuous variable state of spatially correlated photons generated in the spontaneous parametric down-conversion process (SPDC), where tunable non-Gaussian operations are implemented and the post-processed entanglement is certified in real-time using a single-photon sensitive electron multiplying CCD (EMCCD) camera. The local operations are performed using non-Gaussian filters modulated into a programmable spatial light modulator and, by using the EMCCD camera for actively recording the probability distributions of the twin-photons, one has fine control of the Schmidt number of the distilled state. We show that even simple non-Gaussian filters can be finely tuned to a ~67% net gain of the initial entanglement generated in the SPDC process.Comment: 12 pages, 6 figure

    Formation of atom wires on vicinal silicon

    Full text link
    The formation of atomic wires via pseudomorphic step-edge decoration on vicinal silicon surfaces has been analyzed for Ga on the Si(112) surface using Scanning Tunneling Microscopy and Density Functional Theory calculations. Based on a chemical potential analysis involving more than thirty candidate structures and considering various fabrication procedures, it is concluded that pseudomorphic growth on stepped Si(112), both under equilibrium and non-equilibrium conditions, must favor formation of Ga zig-zag chains rather than linear atom chains. The surface is non-metallic and presents quasi-one dimensional character in the lowest conduction band.Comment: submitte

    Ga-induced atom wire formation and passivation of stepped Si(112)

    Full text link
    We present an in-depth analysis of the atomic and electronic structure of the quasi one-dimensional (1D) surface reconstruction of Ga on Si(112) based on Scanning Tunneling Microscopy and Spectroscopy (STM and STS), Rutherford Backscattering Spectrometry (RBS) and Density Functional Theory (DFT) calculations. A new structural model of the Si(112)6 x 1-Ga surface is inferred. It consists of Ga zig-zag chains that are intersected by quasi-periodic vacancy lines or misfit dislocations. The experimentally observed meandering of the vacancy lines is caused by the co-existence of competing 6 x 1 and 5 x 1 unit cells and by the orientational disorder of symmetry breaking Si-Ga dimers inside the vacancy lines. The Ga atoms are fully coordinated, and the surface is chemically passivated. STS data reveal a semiconducting surface and show excellent agreement with calculated Local Density of States (LDOS) and STS curves. The energy gain obtained by fully passivating the surface calls the idea of step-edge decoration as a viable growth method toward 1D metallic structures into question.Comment: Submitted, 13 pages, accepted in Phys. Rev. B, notational change in Fig.

    Framing Public Participation. An Overview of Michoacan State Government

    Get PDF
    Since 2015, local governments of 30 Mexican states have joined the National Open Government Partnership to enhance openness through mechanisms of transparency, accountability and citizen participation. The objective of this paper is to analyze the frameworks promoted by the State Government of Michoacán on public participation since the adoption of an open government policy. To achieve the objective, press releases from the Michoacán State Government’s page were collected and subsequently examined through aframing analysis. Findings indicate that this subnational government has framed public participation in two ways: as a democratic advance and as a transfer of responsibilities to citizens. At the same time, there is a recognition of new public and private actors sharing public decisions with the government. Despite the progress found in this subnational context, the authors warn of serious risks due to the absence of clear rules for the implementation of mechanisms for public participation.Desde 2015, los gobiernos de 30 entidades federativas en México se adhirieron a la iniciativa nacional de Gobierno Abierto para impulsar la apertura del Estado mediante mecanismos de transparencia, rendición de cuentas y participación pública. El objetivo de este artículo es analizar los marcos promovidos por el Gobierno del estado de Michoacán sobre la participación pública a partir de la adopción de una política de Gobierno Abierto. Para lograr el objetivo, se recopilaron los comunicados de prensa emitidos por este gobierno y, posteriormente, se examinaron mediante un análisis de encuadre. Los resultados indican que el gobierno de Michoacán enmarcó la participación pública en dos sentidos: como un avance democrático y como una transferencia de responsabilidades hacia los ciudadanos. A su vez, se reconocieron nuevos actores públicos. A pesar de los avances encontrados, los autores advierten la presencia de riesgos derivados de la ausencia de reglas para la participación pública

    Census of HII regions in NGC 6754 derived with MUSE: Constraints on the metal mixing scale

    Get PDF
    We present a study of the HII regions in the galaxy NGC 6754 from a two pointing mosaic comprising 197,637 individual spectra, using Integral Field Spectrocopy (IFS) recently acquired with the MUSE instrument during its Science Verification program. The data cover the entire galaxy out to ~2 effective radii (re ), sampling its morphological structures with unprecedented spatial resolution for a wide-field IFU. A complete census of the H ii regions limited by the atmospheric seeing conditions was derived, comprising 396 individual ionized sources. This is one of the largest and most complete catalogue of H ii regions with spectroscopic information in a single galaxy. We use this catalogue to derive the radial abundance gradient in this SBb galaxy, finding a negative gradient with a slope consistent with the characteristic value for disk galaxies recently reported. The large number of H ii regions allow us to estimate the typical mixing scale-length (rmix ~0.4 re ), which sets strong constraints on the proposed mechanisms for metal mixing in disk galaxies, like radial movements associated with bars and spiral arms, when comparing with simulations. We found evidence for an azimuthal variation of the oxygen abundance, that may be related with the radial migration. These results illustrate the unique capabilities of MUSE for the study of the enrichment mechanisms in Local Universe galaxies.Comment: 13 pages, 7 Figurs, accepted for publishing in A&

    Adaptation and Testing of the Factorial Structure of the Physical Education Grit Scale for Use in Secondary Education in Spain

    Get PDF
    The challenges faced by students during Physical Education classes embrace both physical and academic aspects. Therefore, each individual possesses a series of internal psychological mechanisms, such as Grit, which allow them to adapt and overcome the vicissitudes. However, there are no scales that assess Grit in Span. Thus, the aim of the present study is to test the factor structure of the Physical Education Grit Scale in Span of Physical Education classes. For this purpose, 857 secondary school students took part in the present study. In order to test the factor structure, a confirmatory factor analysis, an exploratory factor analysis, an analysis of the reliability of the questionnaire and an analysis of temporal stability were carried out. The results showed that the factor structure consisted of two factors and four sub-factors (¿2/df = 2.17 (p = 0.001); CFI = 0.96; TLI = 0.96; IFI = 0.96; RMSEA = 0.051; SRMR = 0.037). In addition, the reliability and temporal stability analyses showed acceptable indices. Based on these results, evidence of reliability and validity of the Physical Education Grit Scale in Span of Physical Education is provided

    Paricalcitol reduces peritoneal fibrosis in mice through the activation of regulatory T cells and reduction in IL-17 production

    Get PDF
    Fibrosis is a significant health problem associated with a chronic inflammatory reaction. The precise mechanisms involved in the fibrotic process are still poorly understood. However, given that inflammation is a major causative factor, immunomodulation is a possible therapeutic approach to reduce fibrosis. The vitamin D receptor (VDR) that is present in all hematopoietic cells has been associated with immunomodulation. We investigated whether the intraperitoneal administration of paricalcitol, a specific activator of the VDR, modulates peritoneal dialysis fluid (PDF)-induced peritoneal fibrosis. We characterized the inflammatory process in the peritoneal cavity of mice treated or not treated with paricalcitol and analyzed the ensuing fibrosis. The treatment reduced peritoneal IL-17 levels, which strongly correlated with a significantly lower peritoneal fibrotic response. In vitro studies demonstrate that both CD4+ and CD8+ regulatory T cells appear to impact the regulation of IL-17. Paricalcitol treatment resulted in a significantly increased frequency of CD8+ T cells showing a regulatory phenotype. The frequency of CD4+ Tregs tends to be increased, but it did not achieve statistical significance. However, paricalcitol treatment increased the number of CD4+ and CD8+ Treg cells in vivo. In conclusion, the activation of immunological regulatory mechanisms by VDR signaling could prevent or reduce fibrosis, as shown in peritoneal fibrosis induced by PDF exposure in mice.This study was supported by RETICS 06/0016 (VFM, RS) and FIS PI 09/0064 (RS) from the Fondo de Investigaciones Sanitarias (Health Research Fund). MLC was funded by SAF 2013-47611-R, SAF 2010-21249, and SAF 2007-61201 from the Ministerio de Economía y competitividad. MRO was supported by RETICS 12/0021,S2012DMD2321 from the Comunidad Autónoma de Madrid, PI 11/01854 from Fondo Investigaciones Sanitarias. GTGM was supported by Renal Foundation Íñigo Álvarez de Toledo, FIBHULP, and by Severo Ochoa FoundationPeer Reviewe
    corecore