5,963 research outputs found

    Influence of aluminum doping on the properties of LiCoO2 and LiNi0.5Co0.5O2 oxides

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    We have prepared LiCo1−yAlyO2 and LiNi0.5−yAlyCo0.5O2 (0≤y≤0.3) powder samples by a low temperature sol–gel method using succinic acid as chelating agent. We have studied the details of their crystallographic and local structure by X-ray diffraction (XRD) and FTIR spectroscopy, respectively; we have analyzed their chemical composition by ICP and obtained information about the morphology of the polycrystalline particles by SEM. Also, we have studied the electrochemical performance of the as-prepared materials in the LiLiNi0.5−yAlyCo0.5O2 cells cycled in the potential range 2.5–4.2 V finding that the overall capacity of the oxides has been reduced due to the metal substitution. For example, at 4.2 V cut-off, the charge capacity of the LiLiNi0.35Al0.15Co0.5O2 cell is ca. 115 mA h/g. However, more stable charge–discharge cycling performances have been obtained as compared to those displayed by the native oxides. Finally, we have characterized the kinetics of Li-diffusion by the galvanostatic intermittent titration technique and, according to our results, Al substitution provides an increase in the chemical diffusion coefficients of Li ions in the LiNi0.5−yAlyCo0.5O2 matrix.Spanish and French Foreing Office; PAI Picasso 00717TCSpanish and French Foreing Office; HF 1999-010

    PMCTrack: Delivering performance monitoring counter support to the OS scheduler

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    Hardware performance monitoring counters (PMCs) have proven effective in characterizing application performance. Because PMCs can only be accessed directly at the OS privilege level, kernellevel tools must be developed to enable the end-user and userspace programs to access PMCs. A large body of work has demonstrated that the OS can perform effective runtime optimizations in multicore systems by leveraging performance-counter data. Special attention has been paid to optimizations in the OS scheduler. While existing performance monitoring tools greatly simplify the collection of PMC application data from userspace, they do not provide an architecture-agnostic kernel-level mechanism that is capable of exposing high-level PMC metrics to OS components, such as the scheduler. As a result, the implementation of PMC-based OS scheduling schemes is typically tied to specific processor models. To address this shortcoming we present PMCTrack, a novel tool for the Linux kernel that provides a simple architecture-independent mechanism that makes it possible for the OS scheduler to access per-thread PMC data. Despite being an OSoriented tool, PMCTrack still allows the gathering of monitoring data from userspace, enabling kernel developers to carry out the necessary offline analysis and debugging to assist them during the scheduler design process. In addition, the tool provides both the OS and the user-space PMCTrack components with other insightful metrics available in modern processors and which are not directly exposed as PMCs, such as cache occupancy or energy consumption. This information is also of great value when it comes to analyzing the potential benefits of novel scheduling policies on real systems. In this paper, we analyze different case studies that demonstrate the flexibility, simplicity and powerful features of PMCTrack.Facultad de InformáticaInstituto de Investigación en Informátic

    PMCTrack: Delivering performance monitoring counter support to the OS scheduler

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    Hardware performance monitoring counters (PMCs) have proven effective in characterizing application performance. Because PMCs can only be accessed directly at the OS privilege level, kernellevel tools must be developed to enable the end-user and userspace programs to access PMCs. A large body of work has demonstrated that the OS can perform effective runtime optimizations in multicore systems by leveraging performance-counter data. Special attention has been paid to optimizations in the OS scheduler. While existing performance monitoring tools greatly simplify the collection of PMC application data from userspace, they do not provide an architecture-agnostic kernel-level mechanism that is capable of exposing high-level PMC metrics to OS components, such as the scheduler. As a result, the implementation of PMC-based OS scheduling schemes is typically tied to specific processor models. To address this shortcoming we present PMCTrack, a novel tool for the Linux kernel that provides a simple architecture-independent mechanism that makes it possible for the OS scheduler to access per-thread PMC data. Despite being an OSoriented tool, PMCTrack still allows the gathering of monitoring data from userspace, enabling kernel developers to carry out the necessary offline analysis and debugging to assist them during the scheduler design process. In addition, the tool provides both the OS and the user-space PMCTrack components with other insightful metrics available in modern processors and which are not directly exposed as PMCs, such as cache occupancy or energy consumption. This information is also of great value when it comes to analyzing the potential benefits of novel scheduling policies on real systems. In this paper, we analyze different case studies that demonstrate the flexibility, simplicity and powerful features of PMCTrack.Facultad de InformáticaInstituto de Investigación en Informátic

    Definición, selección y consolidación de la Raza Caprina Florida

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    El grupo de investigación Pastos arbustivos, comenzó a trabajar en la definición, selección y optimización de los sistemas de explotación de la raza Florida en 1985, en el rebaño experimental que la Diputación de Sevilla creó mediante convenio con José Antonio Sánchez Romero. En 1991, y dentro de esa colaboración se publica el libro Raza Caprina Florida Sevillana en el que se define y se dan los primeros datos de esta raza, demostrando científicamente sus diferencias con otras razas andaluzas. A partir de esta fecha la Diputación de Sevilla abandona el proyecto, continuando el trabajo el grupo de investigación y D. José A. Sánchez Romero hasta 1994. En este periodo se consiguen grandes avances en la selección y optimización del sistema semiextensivo de explotación pasándose de los 432 kg de leche en 216 días de los primeros controles a más de 600 kg en lactaciones de nueve meses. En 1994, el grupo firma un convenio con la Excma. Diputación de Córdoba para el mantenimiento de un rebaño en estabulación en sus instalaciones, siguiendo desde entonces con los trabajos de selección y consolidación así como la optimización de los sistemas intensivos de producción. Las lactaciones controladas bajo este sistema superan los 750 kg en 290 días de lactación. Bajo este convenio, la Diputación de Córdoba ha facilitado más de 100 animales selectos a los ganaderos de la provincia. En 1996, el Grupo de investigación promueve la creación de la Asociación Española de Criadores de la Raza Caprina Florida, a la que pertenece desde entonces.El grupo de investigación Pastos arbustivos, comenzó a trabajar en la definición, selección y optimización de los sistemas de explotación de la raza Florida en 1985, en el rebaño experimental que la Diputación de Sevilla creó mediante convenio con José Antonio Sánchez Romero. En 1991, y dentro de esa colaboración se publica el libro Raza Caprina Florida Sevillana en el que se define y se dan los primeros datos de esta raza, demostrando científicamente sus diferencias con otras razas andaluzas. A partir de esta fecha la Diputación de Sevilla abandona el proyecto, continuando el trabajo el grupo de investigación y D. José A. Sánchez Romero hasta 1994. En este periodo se consiguen grandes avances en la selección y optimización del sistema semiextensivo de explotación pasándose de los 432 kg de leche en 216 días de los primeros controles a más de 600 kg en lactaciones de nueve meses. En 1994, el grupo firma un convenio con la Excma. Diputación de Córdoba para el mantenimiento de un rebaño en estabulación en sus instalaciones, siguiendo desde entonces con los trabajos de selección y consolidación así como la optimización de los sistemas intensivos de producción. Las lactaciones controladas bajo este sistema superan los 750 kg en 290 días de lactación. Bajo este convenio, la Diputación de Córdoba ha facilitado más de 100 animales selectos a los ganaderos de la provincia. En 1996, el Grupo de investigación promueve la creación de la Asociación Española de Criadores de la Raza Caprina Florida, a la que pertenece desde entonces

    IR characterization of Ln2−xSrxCoO4 (x≥1; Ln=La, Nd) oxides

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    [Abstract] We have recorded the FTIR spectra of powder samples of Ln2−xSrxCoO4 (Ln=La, Nd) at room temperature. We have identified the infrared active modes (3A2u+4Eu), and analyzed how they change as a function of Ln and the Sr doping. We correlate the obtained results with structural data obtained from powder X-ray diffraction studies and with the electronic properties displayed by these samples

    ESTUDIO DEL PERFORMANCE DE LOS GRUPOS ESTRATÉGICOS EN EL SISTEMA DE FRANQUICIA ESPAÑOL

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    La preocupación por considerar la heterogeneidad en los comportamientos empresariales dentro de un sector de actividad, ha sido uno de los principales motivos para la búsqueda e identificación de grupos estratégicos, generando un debate inagotable en el ámbito de la estrategia empresarial. Sin embargo, esta preocupación no se ha limitado a identificar arquetipos o configuraciones empresariales, sino que también se ha extendido al estudio de posibles diferencias en el rendimiento entre los grupos identificados. En el presente trabajo, intentamos dar respuesta a esta doble preocupación y todo ello centrándonos en el ámbito de la franquicia. Para ello, se ha elaborado una base de datos con el total de cadenas franquiciadoras (664) que en el año 2005 operaban en España. Los resultados obtenidos revelan la existencia de cinco grupos estratégicos (tipos de franquiciadores) perfectamente diferenciados, los cuales son descritos a partir de las variables estratégicas que los definen. Igualmente, se demuestra la existencia de diferencias en los resultados inter-grupales a partir de determinados indicadores de desempeño (ingresos, resultados ordinarios y rentabilidad)

    Severe Neurological Abnormalities in a Young Boy with Impaired Thyroid Hormone Sensitivity Due to a Novel Mutation in the MCT8 Gene

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    Monocarboxylate transporter 8 (MCT8) is an active and specific thyroid hormone transporter into neurons. MCT8 mutations cause an X-linked condition known as Allan-Herndon-Dudley syndrome and are characterized by impaired psychomotor development and typical abnormal thyroid function. We describe a 10-year-old boy with severe cognitive disability, axial hypotonia, spastic quadriplegia and sporadic dyskinetic episodes. He initially presented with thyroid dysfunction (high FT3, low rT3, low FT4 and normal TSH) and generalized retardation of the cerebral and cerebellar myelination in brain magnetic resonance imaging. The clinical and laboratory findings led to sequencing of the SLC16A2/MCT8 gene, which identified a novel missense mutation in exon 5. The study of peripheral markers of thyroid function suggests a paradoxical state of thyrotoxicosis in some peripheral tissues. Our patient had a typical clinical presentation at birth but because of the rarity of his disease his diagnosis was not made until the age of 7. The delay can also be explained by the omission of the free T3 assay in the first thyroid evaluation performed. This case therefore highlights the possible benefit of including the T3 assay in the study of patients with severe psychomotor disability of unknown etiology, thus eliminating extra costs for unnecessary complementary diagnostic tests.info:eu-repo/semantics/publishedVersio

    PMCTrack: Delivering performance monitoring counter support to the OS scheduler

    Get PDF
    Hardware performance monitoring counters (PMCs) have proven effective in characterizing application performance. Because PMCs can only be accessed directly at the OS privilege level, kernellevel tools must be developed to enable the end-user and userspace programs to access PMCs. A large body of work has demonstrated that the OS can perform effective runtime optimizations in multicore systems by leveraging performance-counter data. Special attention has been paid to optimizations in the OS scheduler. While existing performance monitoring tools greatly simplify the collection of PMC application data from userspace, they do not provide an architecture-agnostic kernel-level mechanism that is capable of exposing high-level PMC metrics to OS components, such as the scheduler. As a result, the implementation of PMC-based OS scheduling schemes is typically tied to specific processor models. To address this shortcoming we present PMCTrack, a novel tool for the Linux kernel that provides a simple architecture-independent mechanism that makes it possible for the OS scheduler to access per-thread PMC data. Despite being an OSoriented tool, PMCTrack still allows the gathering of monitoring data from userspace, enabling kernel developers to carry out the necessary offline analysis and debugging to assist them during the scheduler design process. In addition, the tool provides both the OS and the user-space PMCTrack components with other insightful metrics available in modern processors and which are not directly exposed as PMCs, such as cache occupancy or energy consumption. This information is also of great value when it comes to analyzing the potential benefits of novel scheduling policies on real systems. In this paper, we analyze different case studies that demonstrate the flexibility, simplicity and powerful features of PMCTrack.Facultad de InformáticaInstituto de Investigación en Informátic

    Simultaneous Surface Plasmon Resonance and X-ray Absorption Spectroscopy

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    We present here an experimental set-up to perform simultaneously measurements of surface plasmon resonance (SPR) and X-ray absorption spectroscopy (XAS) in a synchrotron beamline. The system allows measuring in situ and in real time the effect of X-ray irradiation on the SPR curves to explore the interaction of X-rays with matter. It is also possible to record XAS spectra while exciting SPR in order to detect the changes in the electronic configuration of thin films induced by the excitation of surface plasmons. Combined experiments recording simultaneously SPR and XAS curves while scanning different parameters can be carried out. The relative variations in the SPR and XAS spectra that can be detected with this set-up ranges from 10-3 to 10-5, depending on the particular experiment
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