713 research outputs found

    How is ICT use linked to household transport expenditure? A cross-national macro analysis of the influence of home broadband access

    Get PDF
    Understanding of the interactions between Information and Communication Technologies (ICT) and physical mobility is a major area of research with practical applications in a number of fields. Very little, however, is known regarding how these relationships vary on a cross-national basis, including across countries at different stages in development. To address this gap, this paper presents an analysis of household transport expenditure as a function of the available variables, with a particular focus on the ICT. This analysis is based on a cross-sectional dataset from 2010 comprising information on 33 countries including average household transport expenditure, ICT represented by the percentage of households with Internet access at home, and a number of contextual macroeconomic and infrastructural variables. Using a log-log framework we find that, in our sample of countries, household transport expenditure is negatively associated with Internet penetration with an elasticity of − 0.394. We verify this to be robust to endogeneity using presence of restrictions on foreign ownership in the Internet market as an instrumental variable. We also control for potential differences in data quality across countries using the Corruption Perceptions Index. To the best of our knowledge, this is the first attempt to quantify this relationship at a cross-national level while also controlling for endogeneity and data quality issues. Among the control variables, we observe the estimated effects to be intuitive, and consistent with existing research and microeconomic understandings of the behaviour of individuals and households

    Fokker-Planck type equations with Sobolev diffusion coefficients and BV drift coefficients

    Full text link
    In this paper we give an affirmative answer to an open question mentioned in [Le Bris and Lions, Comm. Partial Differential Equations 33 (2008), 1272--1317], that is, we prove the well-posedness of the Fokker-Planck type equations with Sobolev diffusion coefficients and BV drift coefficients.Comment: 11 pages. The proof has been modifie

    Las leyendas y mitos helenos en la interpolación de la “Tragicomedia de Calisto y Melibea"

    Get PDF
    En este trabajo se estudian las leyendas y mitos de raigambre helénica incorporados a La Celestina mediante la extensa interpolación realizada en su composición a comienzos del siglo XVI. De este modo, a partir de un análisis del texto de la Tragicomedia, se examinan los principales elementos míticos y legendarios helénicos añadidos en el paso de Comedia a Tragicomedia de Calisto y Melibea por medio de su ampliación desde XVI hasta XXI actos, junto a otros añadidos y modificaciones. En el análisis se destaca el tópico de la nox longa de Júpiter en La Celestina, ya que representa una propuesta y un análisis novedoso sobre el proceso de alargamiento de los amores y sobre el personaje Sosia, así como sobre la justificación del propio título de Tragicomedia.In this work we study the legends and myths of Hellenic roots incorporated into La Celestina through the extensive interpolation made in its composition at the beginning of the 16th century. In this way, from an analysis of the text of the Tragicomedy, the main mythic and legendary Hellenic elements added in the passage from Comedy to Tragicomedy of Calisto and Melibea are examined through their expansion from XVI to XXI acts, together to other additions and modifications. In the analysis it is remarkable the topic of nox longa of Jupiter in La Celestina, since it represents a proposal and a novel analysis about the lengthening process of the loves and the character Sosia, as well as about the justification of the title of Tragicomedia

    Approximating a Wavefunction as an Unconstrained Sum of Slater Determinants

    Full text link
    The wavefunction for the multiparticle Schr\"odinger equation is a function of many variables and satisfies an antisymmetry condition, so it is natural to approximate it as a sum of Slater determinants. Many current methods do so, but they impose additional structural constraints on the determinants, such as orthogonality between orbitals or an excitation pattern. We present a method without any such constraints, by which we hope to obtain much more efficient expansions, and insight into the inherent structure of the wavefunction. We use an integral formulation of the problem, a Green's function iteration, and a fitting procedure based on the computational paradigm of separated representations. The core procedure is the construction and solution of a matrix-integral system derived from antisymmetric inner products involving the potential operators. We show how to construct and solve this system with computational complexity competitive with current methods.Comment: 30 page

    COMET-NARVAL ACQUISITION notice

    No full text
    SEP NESTER S2I translated by A.M. Dujardi

    Fracture toughness in some hetero-modulus composite carbides: carbon inclusions and voids. Advances in Applied Ceramics

    Get PDF
    Fracture toughness of ceramics in some cases can be significantly improved by the inclusion of low-modulus phase and even voids. Structure and mechanical characteristics of dense ceramic composites synthesised by reactive hot pressing of TiC-B4C powder mixtures at 1800 - 1950°С under 30MPa during 16 minutes are investigated. X-Ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy (SEM and EDX) have shown that during hot pressing solid phase chemical interaction 2TiС + B4C = 2TiВ2 + 3С has occurred resulting in TiB2-TiC-C, TiB2-C or TiB2-B4C-C hetero-modulus composite formation with approximately 1μm carbon precipitates. The volume of such precipitated carbon can reach 35 vol. %. The fracture toughness depends on the precipitate size and amount of graphite precipitation and has a distinct maximum K1C = 10MPa∙m1/2 at nearly 7 vol. % . Such fracture toughness behaviour is explained by the proposed model of crack propagation and the model-based assessment of hetero-modulus ceramic fracture toughness. It is shown that voids and low modulus carbon inclusions blunt the cracks and can increase ceramic toughness. The later has been demonstrated in the another carbon containing ceramic Cr2AlC, so named MAX phase material, when thin film fracture resistance increases as the ceramic was deposited to be porous

    Sitagliptin improved glucose assimilation in detriment of fatty-acid utilization in experimental type-II diabetes: Role of GLP-1 isoforms in Glut4 receptor trafficking

    Full text link
    Background: The distribution of glucose and fatty-acid transporters in the heart is crucial for energy consecution and myocardial function. In this sense, the glucagon-like peptide-1 (GLP-1) enhancer, sitagliptin, improves glucose homeostasis but it could also trigger direct cardioprotective actions, including regulation of energy substrate utilization. Methods: Type-II diabetic GK (Goto-Kakizaki), sitagliptin-treated GK (10 mg/kg/day) and wistar rats (n = 10, each) underwent echocardiographic evaluation, and positron emission tomography scanning for [ 18 F]-2-fluoro-2-deoxy-d-glucose ( 18 FDG). Hearts and plasma were isolated for biochemical approaches. Cultured cardiomyocytes were examined for receptor distribution after incretin stimulation in high fatty acid or high glucose media. Results: Untreated GK rats exhibited hyperglycemia, hyperlipidemia, insulin resistance, and plasma GLP-1 reduction. Moreover, GK myocardium decreased 18 FDG assimilation and diastolic dysfunction. However, sitagliptin improved hyperglycemia, insulin resistance, and GLP-1 levels, and additionally, enhanced 18 FDG uptake and diastolic function. Sitagliptin also stimulated the sarcolemmal translocation of the glucose transporter-4 (Glut4), in detriment of the fatty acyl translocase (FAT)/CD36. In fact, Glut4 mRNA expression and sarcolemmal translocation were also increased after GLP-1 stimulation in high-fatty acid incubated cardiomyocytes. PI3K/Akt and AMPKα were involved in this response. Intriguingly, the GLP-1 degradation metabolite, GLP-1(9-36), showed similar effects. Conclusions: Besides of its anti-hyperglycemic effect, sitagliptin-enhanced GLP-1 may ameliorate diastolic dysfunction in type-II diabetes by shifting fatty acid to glucose utilization in the cardiomyocyte, and thus, improving cardiac efficiency and reducing lipolysisThis work was supported by national grants from Ministerio de Educación y Ciencia (SAF2009-08367), Comunidad de Madrid (CCG10-UAM/BIO-5289), and PIE13/00051 and PI14/00386 (IS. Carlos III). Merck Sharp and Dohme (Darmstadt, Germany) provided sitagliptin and partial financial support to the conduct of the stud

    Cocoa and Cocoa Fibre Intake Modulate Reactive Oxygen Species and Immunoglobulin Production in Rats Submitted to Acute Running Exercise

    Full text link
    Acute high-intensity exercise can impair the immune system, and lead to oxidative stress. Cocoa intake might help in protecting against oxidative damage and impaired immune functioning. The aim of this study was to establish the effect of cocoa and cocoa fibre on the oxidative status and the immunoglobulin (Ig) production of rats following a bout of acute exercise on a treadmill. The production of reactive oxygen species (ROS) by macrophages and the concentration of serum and mucosal Ig was assessed 16 h after the running session. Exercise increased ROS production and decreased the serum IgG concentration and the salivary gland IgM content. A cocoa fibre-enriched diet prevented the increased ROS production and the reduction in salivary IgM induced by exercise, although it decreased the IgA content in serum and the salivary glands. Overall, cocoa, by means of its fibre content, can partially prevent the alterations in ROS and Ig production induced by a single session of intensive running exercise
    corecore