1,926 research outputs found

    Ernest Renan among us : from antichrist to prophet

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    El historiador francés Ernest Renan (1823-1892) publicó en 1863 una Vida de Jesús que cuestionaba la divinidad del mismo. Causó escándalo e intentos de refutación. Se estudian algunas reacciones en América Latina y se describe el proceso por el cual Renan llegó posteriormente a ser aceptado por círculos conservadores.The French historian Ernest Renan (1823-1892) published in 1863 a Life of Jesus that questioned his divinity. The book aroused scandal and attempts of rebuttal. This analysis examines some of the reactions in Latin America, as well as the process by which Renan came later to be accepted in conservative circles.Fil: Taboada, Hernán G. H.. Universidad Nacional Autónoma de Méxic

    From African Spain to Theocratic America : notes on the Ideas of Simón Bolívar

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    Las ideas de Simón Bolívar sobre América y sobre Europa han recibido alguna atención de los investigadores. Mucho menos las que expresó sobre Asia y África. Aunque fueron marginales a su pensamiento, la reunión de sus alusiones al respecto permite arrojar alguna luz sobre la reflexión de la Independencia y sobre los cambios que el Libertador experimentó en su percepción del naciente mundo que aparecía ante sus ojos. Partiendo de una actitud orientalista y despectiva inicial, con el tiempo llegó a pensar que el Oriente no podía descartarse como influencia en las instituciones americanas.Simón Bolivar’s ideas regarding America and Europe have attracted some attention from academic researchers, but much less so those regarding Asia and Africa. Even though they were secondary to his thought, gathering these references allows us to throw some light on Bolivar’s and his Hispanic- American contemporaries’ views on Independence, and on the changes in the Libertador’s perception of the nascent American world taking shape before his eyes. Departing from an Orientalist and contemptuous attitude at first, Bolivar eventually arrives at the idea that the “Orient" could not be dismissed as an influence over American institutions.Fil: Taboada, Hernán G. H.

    Counterfactual Density Estimation using Kernel Stein Discrepancies

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    Causal effects are usually studied in terms of the means of counterfactual distributions, which may be insufficient in many scenarios. Given a class of densities known up to normalizing constants, we propose to model counterfactual distributions by minimizing kernel Stein discrepancies in a doubly robust manner. This enables the estimation of counterfactuals over large classes of distributions while exploiting the desired double robustness. We present a theoretical analysis of the proposed estimator, providing sufficient conditions for consistency and asymptotic normality, as well as an examination of its empirical performance

    Snap-8 corrosion program quarterly progress report, period ending 28 feb. 1965

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    SNAP-8 corrosion program - hydrogen solubility in sodium-potassium, permeability of hydrogen and deuterum through stainless steel, and phase equilibri

    An Efficient Doubly-Robust Test for the Kernel Treatment Effect

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    The average treatment effect, which is the difference in expectation of the counterfactuals, is probably the most popular target effect in causal inference with binary treatments. However, treatments may have effects beyond the mean, for instance decreasing or increasing the variance. We propose a new kernel-based test for distributional effects of the treatment. It is, to the best of our knowledge, the first kernel-based, doubly-robust test with provably valid type-I error. Furthermore, our proposed algorithm is efficient, avoiding the use of permutations

    Quasi-equilibrium and quantum correlation in an open spin-pair system

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    Quasi-equilibrium states that can be prepared in solids through Nuclear Magnetic Resonance (NMR) techniques are out-of-equilibrium states that slowly relax towards thermodynamic equilibrium with the lattice. In this work, we use the quantum discord dynamics as a witness of the quantum correlation in this kind of state. The studied system is a dipole interacting spin pair whose initial state is prepared with the NMR Jeener-Broekaert pulse sequence, starting from equilibrium at high temperature and high external magnetic field. It then evolves as an open quantum system within two different dynamic scenarios: adiabatic decoherence driven by the coupling of the pairs to a common phonon field, described within a non-markovian approach; and spin-lattice relaxation represented by a markovian master equation, and driven by thermal fluctuations. In this way, the studied model is endowed with the dynamics of a realistic solid sample. The quantum discord rapidly increases during the preparation of the initial state, escalating several orders of magnitude compared with thermal equilibrium at room temperature. Despite the vanishing of coherences during decoherence, the quantum discord oscillates around this high value and undergoes a minor attenuation, holding the same order of magnitude as the initial state. Finally, the quantum discord dissipates within a time scale shorter than but comparable to spin-lattice relaxation.Comment: 19 pages, 5 figure

    Strain relaxation of GaAs/Ge crystals on patterned Si substrates

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    Taboada, A. G. et al.We report on the mask-less integration of GaAs crystals several microns in size on patterned Si substrates by metal organic vapor phase epitaxy. The lattice parameter mismatch is bridged by first growing 2-μm-tall intermediate Ge mesas on 8-μm-tall Si pillars by low-energy plasma enhanced chemical vapor deposition. We investigate the morphological evolution of the GaAs crystals towards full pyramids exhibiting energetically stable {111} facets with decreasing Si pillar size. The release of the strain induced by the mismatch of thermal expansion coefficients in the GaAs crystals has been studied by X-ray diffraction and photoluminescence measurements. The strain release mechanism is discussed within the framework of linear elasticity theory by Finite Element Method simulations, based on realistic geometries extracted from scanning electron microscopy images. © 2014 AIP Publishing LLC.Financial support by the Swiss Federal Program Nano-Tera through projects NEXRAY and COSMICMOS and Spanish MINECO and CAM through projects EPIC-NANOTICS and Q&C Light are gratefully acknowledged.Peer Reviewe

    Compositional analysis of InAs-GaAs-GaSb heterostructures by low-loss electron energy loss spectroscopy

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    As an alternative to Core-Loss Electron Energy Loss Spectroscopy, Low-Loss EELS is suitable for compositional analysis of complex heterostructures, such as the InAs-GaAs-GaSb system, since in this energy range the edges corresponding to these elements are better defined than in Core-Loss. Furthermore, the analysis of the bulk plasmon peak, which is present in this energy range, also provides information about the composition. In this work, compositional information in an InAs-GaAs-GaSb heterostructure has been obtained from Low-Loss EEL spectra
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