7,156 research outputs found

    Proof of a conjecture by Gazeau et al. using the Gould Hopper polynomials

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    We prove the "strong conjecture" expressed by Gazeau et al. in arXiv:1203.3936v1 [math-ph] about the coefficients of the Taylor expansion of the exponential of a polynomial. This implies the "weak conjecture" as a special case. The proof relies mainly about properties of the Gould-Hopper polynomials

    A model for the wind direction signature in the stokes smissin sector from the ocean surfaces at microwave frequencies

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    This paper presents a model of the Stokes emission vector from the ocean surface. The ocean surface is described as an ensemble of facets with Cox and Munk's (1954) Gram-Charlier slope distribution. The study discusses the impact of different up-wind and cross-wind rms slopes, skewness, peakedness, foam cover models and atmospheric effects on the azimuthal variation of the Stokes vector, as well as the limitations of the model. Simulation results compare favorably, both in mean value and azimuthal dependence, with SSM/I data at 53/spl deg/ incidence angle and with JPL's WINDRAD measurements at incidence angles from 30/spl deg/ to 65/spl deg/, and at wind speeds from 2.5 to 11 m/s.Peer ReviewedPostprint (published version

    The valuation of clean spread options: linking electricity, emissions and fuels

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    The purpose of the paper is to present a new pricing method for clean spread options, and to illustrate its main features on a set of numerical examples produced by a dedicated computer code. The novelty of the approach is embedded in the use of a structural model as opposed to reduced-form models which fail to capture properly the fundamental dependencies between the economic factors entering the production process

    Deconfining transition in two-flavor QCD

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    The order and the nature of the finite-temperature phase transition of QCD with two flavors of dynamical quarks is investigated. An analysis of the critical exponent of the specific heat is performed through finite-size and finite-mass scaling of various susceptibilities. Dual superconductivity of QCD vacuum is investigated using a disorder parameter, namely the v.e.v. of a monopole creation operator. Hybrid R simulations were run at lattice spatial sizes of 12312^3, 16316^3, 20320^3 and 32332^3 and temporal size Nt=4N_t=4, with quark masses in the range amq=0.30.01am_q = 0.3 - 0.01.Comment: Lattice2003(topology), 3 page

    On Eigenvalue spacings for the 1-D Anderson model with singular site distribution

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    We study eigenvalue spacings and local eigenvalue statistics for 1D lattice Schrodinger operators with Holder regular potential, obtaining a version of Minami's inequality and Poisson statistics for the local eigenvalue spacings. The main additional new input are regular properties of the Furstenberg measures and the density of states obtained in some of the author's earlier work.Comment: 13 page

    Color confinement and dual superconductivity in unquenched QCD

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    We report on evidence from lattice simulations that confinement is produced by dual superconductivity of the vacuum in full QCD as in quenched QCD. Preliminary information is obtained on the order of the deconfining phase transition.Comment: 4 pages, to appear in the Proceedings of Quark Matter 02 - The XVI International Conference on Ultrarelativistic Nucleus-Nucleus Collision

    Where is the warm H2 ? A search for H2 emission from disks around Herbig Ae/Be stars

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    Mid-IR emission lines of H2 are useful probes to determine the mass of warm gas present in the surface layers of disks. Numerous observations of Herbig Ae/Be stars (HAeBes) have been performed, but only 2 detections of mid-IR H2 toward HD97048 and AB Aur have been reported. We aim at tracing the warm gas in the disks of 5 HAeBes with gas-rich environments and physical characteristics close to those of AB Aur and HD97048, to discuss whether the detections toward these 2 objects are suggestive of peculiar conditions for the gas. We search for the H2 S(1) emission line at 17.035 \mu\m with VISIR, and complemented by CH molecule observations with UVES. We gather the H2 measurements from the literature to put the new results in context and search for a correlation with some disk properties. None of the 5 VISIR targets shows evidence for H2 emission. From the 3sigma upper limits on the integrated line fluxes we constrain the amount of optically thin warm gas to be less than 1.4 M_Jup in the disk surface layers. There are now 20 HAeBes observed with VISIR and TEXES instruments to search for warm H2, but only two detections (HD97048 and AB Aur) were made so far. We find that the two stars with detected warm H2 show at the same time high 30/13 \mu\m flux ratios and large PAH line fluxes at 8.6 and 11.3 \mu\m compared to the bulk of observed HAeBes and have emission CO lines detected at 4.7 \mu\m. We detect the CH 4300.3A absorption line toward both HD97048 and AB Aur with UVES. The CH to H2 abundance ratios that this would imply if it were to arise from the same component as well as the radial velocity of the CH lines both suggest that CH arises from a surrounding envelope, while the detected H2 would reside in the disk. The two detections of the S(1) line in the disks of HD97048 and AB Aur suggest either peculiar physical conditions or a particular stage of evolution.Comment: accepted for publication in A&A : 10 pages, 6 figure

    Adaptation “in the Wild”: Ontology-Based Personalization of Open-Corpus Learning Material

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    Abstract. Teacher and students can use WWW as a limitless source of learning material for nearly any subject. Yet, such abundance of content comes with the problem of finding the right piece at the right time. Conventional adaptive educational systems cannot support personalized access to open-corpus learning material as they rely on manually constructed content models. This paper presents an approach to this problem that does not require intervention from a human expert. The approach has been implemented in an adaptive system that recommends students supplementary reading material and adaptively annotates it. The results of the evaluation experiment have demonstrated several significant effects of using the system on students ’ learning

    Adaptation “in the Wild”: Ontology-Based Personalization of Open-Corpus Learning Material

    Get PDF
    Teacher and students can use WWW as a limitless source of learning material for nearly any subject. Yet, such abundance of content comes with the problem of finding the right piece at the right time. Conventional adaptive educational systems cannot support personalized access to open-corpus learning material as they rely on manually constructed content models. This paper presents an approach to this problem that does not require intervention from a human expert. The approach has been implemented in an adaptive system that recommends students supplementary reading material and adaptively annotates it. The results of the evaluation experiment have demonstrated several significant effects of using the system on students’ learning.\u
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