211 research outputs found

    Dynamics of localized structures in vector waves

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    Dynamical properties of topological defects in a twodimensional complex vector field are considered. These objects naturally arise in the study of polarized transverse light waves. Dynamics is modeled by a Vector Complex Ginzburg-Landau Equation with parameter values appropriate for linearly polarized laser emission. Creation and annihilation processes, and selforganization of defects in lattice structures, are described. We find "glassy" configurations dominated by vectorial defects and a melting process associated to topological-charge unbinding.Comment: 4 pages, 5 figures included in the text. To appear in Phys. Rev. Lett. (2000). Related material at http://www.imedea.uib.es/Nonlinear and http://www.imedea.uib.es/Photonics . In this new version, Fig. 3 has been replaced by a better on

    Aplicaciones y seguridad en la implementación de competencias prácticas en entornos de gestión del aprendizaje

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    In this article, some improvements and contributions are introduced into two main features of the Learning Management Systems (LMSs). The first feature is the security and the authentication functionality, where we present a model that combines the traditional authentication based on username and password, with the authentication based on fingerprints. The second feature is the access to remote and virtual laboratories, where we present a middleware architecture that combines the duplicated services provided by both, the laboratories and the LMS, in order to facilitate their integration and to provide a unique access from the LMS to the remote and virtual laboratories.En este artículo exponemos algunas mejoras y aportaciones en dos aspectos de los sistemas de gestión de aprendizaje (LMS). El primer aspecto es la seguridad y la autenticación, donde presentamos una modalidad de combinar la autenticación tradicional de contraseña y nombre de usuario con la autenticación por la técnica biométrica de comparación de huellas dactilares. El segundo aspecto es una arquitectura middleware capaz de dar acceso desde los LMS a distintos laboratorios remotos y virtuales (online) de forma que, se evita la duplicación de los servicios proporcionados por ambas y se reutilizan los servicios proporcionados por los LMS en las sesiones prácticas

    PENGARUH MEKANISME GOOD CORPORATE GOVERNANCE DAN CORPORATE SOCIAL RESPONSIBILITY TERHADAP KINERJA KEUANGAN DENGAN MANAJEMEN LABA SEBAGAI VARIABEL MEDIASI (Studi Empiris pada Perusahaan Manufaktur yang terdaftar di Bursa Efek Indonesia tahun 2014)

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    Penelitian ini bertujuan untuk mengetahui pengaruh langsung antara mekanisme Good Corporate Governance (GCG) dan Corporate Social Responsibility (CSR) terhadap kinerja keuangan maupun melalui manajemen laba sebagai variabel mediasi. Data yang digunakan dalam penelitian ini merupakan data sekunder yang melibatkan 102 perusahaan manufaktur yang terdaftar di Bursa Efek Indonesia (BEI) untuk periode 2014. Data yang digunakan dalam penelitian ini dianalisis menggunakan Partial Least Square (PLS) dan dilakukan dengan bantuan software WarpPLS 5.0. Hasil penelitian menunjukkan mekanisme GCG berpengaruh positif terhadap kinerja keuangan begitu juga dengan CSR terhadap kinerja keuangan. Mekanisme GCG berpengaruh negatif terhadap manajemen laba sedangkan CSR berpengaruh positif terhadap manajemen laba. Manajemen laba berpengaruh negatif terhadap kinerja keuangan. Manajemen laba juga terbukti mampu memediasi pengaruh mekanisme GCG terhadap kinerja keuangan dengan bentuk mediasi sebagian sedangkan dalam memediasi pengaruh CSR terhadap kinerja keuangan, manajemen laba terbukti dapat menjadi mediasi penuh

    Aplicaciones y seguridad en la implementación de competencias prácticas en entornos de gestión del aprendizaje

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    In this article, some improvements and contributions are introduced into two main features of the Learning Management Systems (LMSs). The first feature is the security and the authentication functionality, where we present a model that combines the traditional authentication based on username and password, with the authentication based on fingerprints. The second feature is the access to remote and virtual laboratories, where we present a middleware architecture that combines the duplicated services provided by both, the laboratories and the LMS, in order to facilitate their integration and to provide a unique access from the LMS to the remote and virtual laboratories.<br><br>En este artículo exponemos algunas mejoras y aportaciones en dos aspectos de los sistemas de gestión de aprendizaje (LMS). El primer aspecto es la seguridad y la autenticación, donde presentamos una modalidad de combinar la autenticación tradicional de contraseña y nombre de usuario con la autenticación por la técnica biométrica de comparación de huellas dactilares. El segundo aspecto es una arquitectura middleware capaz de dar acceso desde los LMS a distintos laboratorios remotos y virtuales (online) de forma que, se evita la duplicación de los servicios proporcionados por ambas y se reutilizan los servicios proporcionados por los LMS en las sesiones prácticas

    Trends in incidence and outcomes of revision total hip arthroplasty in Spain: A population based study

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    <p>Abstract</p> <p>Background</p> <p>To analyze changes in incidence and outcomes of patients undergoing revision total hip arthroplasty (RTHA) over an 8-year study period in Spain.</p> <p>Methods</p> <p>We selected all surgical admissions in individuals aged ≥ 40 years who underwent RTHA (ICD-9-CM procedure code 81.53) between 2001 and 2008 from the Spanish National Hospital Discharge Database. Age- and sex-specific incidence rates, Charlson co-morbidity index, length of stay (LOS), costs and in-hospital mortality (IHM) were estimated for each year. Multivariate analyses were conducted to asses time trends.</p> <p>Results</p> <p>32, 280 discharges of patients (13, 391 men/18, 889 women) having undergone RTHA were identified. Overall crude incidence showed a small but significant increase from 20.2 to 21.8 RTHA per 100, 000 inhabitants from 2001 to 2008 (p < 0.01).</p> <p>The incidence increased for men (17.7 to 19.8 in 2008) but did not vary for women (22.3 in 2001 and 22.2 in 2008). Greater increments were observed in patients older than 84 years and in the age group 75-84. In 2001, 19% of RTHA patients had a Charlson Index ≥ 1 and this proportion rose to 24.6% in 2008 (p < 0.001). The ratio RTHA/THA remained stable and around 20% in Spain along the entire period</p> <p>The crude overall in-hospital mortality (IHM) increased from 1.16% in 2001 to 1.77% (p = 0.025) in 2008. For both sexes the risk of death was higher with age, with the highest mortality rates found among those aged 85 or over. After multivariate analysis no change was observed in IHM over time. The mean inflation adjusted cost per patient increased by 78.3%, from 9, 375 to 16, 715 Euros from 2001 to 2008.</p> <p>After controlling for possible confounders using Poisson regression models, we observed that the incidence of RTHA hospitalizations significantly increased for men and women over the period 2001 to 2008 (IRR 1.10, 95% CI 1.03-1.18 and 1.08, 95% CI 1.02-1.14 respectively).</p> <p>Conclusions</p> <p>The crude incidence of RTHA in Spain showed a small but significant increase from 2001 to 2008 with concomitant reductions in LOS, significant increase in co-morbidities and cost per patient.</p

    MEGARA, the new intermediate-resolution optical IFU and MOS for GTC: getting ready for the telescope

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    MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma that is being built by a Consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). The instrument is currently finishing AIV and will be sent to GTC on November 2016 for its on-sky commissioning on April 2017. The MEGARA IFU fiber bundle (LCB) covers 12.5x11.3 arcsec2 with a spaxel size of 0.62 arcsec while the MEGARA MOS mode allows observing up to 92 objects in a region of 3.5x3.5 arcmin2 around the IFU. The IFU and MOS modes of MEGARA will provide identical intermediate-to-high spectral resolutions (RFWHM~6,000, 12,000 and 18,700, respectively for the low-, mid- and high-resolution Volume Phase Holographic gratings) in the range 3700-9800ÅÅ. An x-y mechanism placed at the pseudo-slit position allows (1) exchanging between the two observing modes and (2) focusing the spectrograph for each VPH setup. The spectrograph is a collimator-camera system that has a total of 11 VPHs simultaneously available (out of the 18 VPHs designed and being built) that are placed in the pupil by means of a wheel and an insertion mechanism. The custom-made cryostat hosts a 4kx4k 15-μm CCD. The unique characteristics of MEGARA in terms of throughput and versatility and the unsurpassed collecting are of GTC make of this instrument the most efficient tool to date to analyze astrophysical objects at intermediate spectral resolutions. In these proceedings we present a summary of the instrument characteristics and the results from the AIV phase. All subsystems have been successfully integrated and the system-level AIV phase is progressing as expected

    X chromosome inactivation does not necessarily determine the severity of the phenotype in Rett syndrome patients

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    Rett syndrome (RTT) is a severe neurological disorder usually caused by mutations in the MECP2 gene. Since the MECP2 gene is located on the X chromosome, X chromosome inactivation (XCI) could play a role in the wide range of phenotypic variation of RTT patients; however, classical methylation-based protocols to evaluate XCI could not determine whether the preferentially inactivated X chromosome carried the mutant or the wild-type allele. Therefore, we developed an allele-specific methylation-based assay to evaluate methylation at the loci of several recurrent MECP2 mutations. We analyzed the XCI patterns in the blood of 174 RTT patients, but we did not find a clear correlation between XCI and the clinical presentation. We also compared XCI in blood and brain cortex samples of two patients and found differences between XCI patterns in these tissues. However, RTT mainly being a neurological disease complicates the establishment of a correlation between the XCI in blood and the clinical presentation of the patients. Furthermore, we analyzed MECP2 transcript levels and found differences from the expected levels according to XCI. Many factors other than XCI could affect the RTT phenotype, which in combination could influence the clinical presentation of RTT patients to a greater extent than slight variations in the XCI pattern
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