3,410 research outputs found

    SUNK COSTS HYSTERESIS IN SPANISH MANUFACTURING EXPORTS

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    This paper tests the sunk costs explanation for hysteresis in exports using a sample of Spanish manufacturing firms for the period 1990-2000. The data are drawn from the Spanish Encuesta sobre Estrategias Empresariales. To obtain consistent estimates for sunk costs, we control for all other sources of persistence and use a dynamic random effects multivariate probit model that is estimated through pseudo simulated maximum-likelihood techniques. Our results support the sunk costs explanation for hysteresis. Furthermore, regional spillovers and some firm characteristics such as size, productivity or vertical and horizontal product differentiation are found to have a significant influence on the probability of exporting. El objetivo de este artículo es analizar el papel de los costes irrecuperables como factorexplicativo de la histéresis de las exportaciones. Para ello se hace uso de una muestra deempresas industriales españolas para el período 1999-2000, que proviene de la Encuestasobre Estrategias Empresariales. Con el objetivo de obtener estimaciones consistentespara los costes irrecuperables, controlamos por todas las posibles fuentes alternativas depersistencia y estimamos nuestro modelo usando técnicas de pseudo máximaverosimilitud simulada. Nuestros resultados confirman a los costes irrecuperables comocausante de la histéresis de las exportaciones. Adicionalmente, encontramos que lasexternalidades regionales y algunas características empresariales tales como tamaño,productividad o diferenciación horizontal y vertical tienen un impacto significativosobre la probabilidad de exportar.Histéresis de las exportaciones, costes irrecuperables, modelos dinámicos de elección discrecional hysteresis in trade, sunk costs, dynamic discrete choice models

    Image quality loss and compensation for visually impaired observers

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    The measurement and modeling of image quality are aimed to assist the design and optimization of systems, typically built for ‘normal’ observer vision. But in reality image viewers rarely have perfect vision. There have been few attempts and no universal framework for measuring image quality loss due to visual impairments. The paper presents initial experiments designed to measure still image quality losses, as experienced by observers with visual accommodation problems, by proposing modifications to the Quality Ruler method described in ISO 20462-3:2012. A simple method is then presented, which compensates directly on the display for some of the quality lost due to the impairment. It uses a purpose-built image equalization software. The compensated image is finally examined in terms of quality gained. The losses and gains in image quality are measured on a Standard Quality Scale (SQS), where one unit corresponds to 1 JND. Initial results show that the quality lost due to visual accommodation impairments can be accurately measured with the modified ruler method. The loss is scene-dependent. Partial or full quality compensation can be achieved for such impairments, using image contrast equalization; the level of quality gained also scenedependent

    Power scaling rules for charmonia production and HQEFT

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    We discuss the power scaling rules along the lines of a complete Heavy Quark Effective Field Theory (HQEFT) for the description of heavy quarkonium production through a color-octet mechanism. To this end, we firstly derive a tree-level heavy quark effective Lagrangian keeping both particle-antiparticle mixed sectors allowing for heavy quark-antiquark pair annihilation and creation, but describing only low-energy modes around the heavy quark mass. Then we show the consistency of using HQEFT fields in constructing four-fermion local operators a la NRQCD, to be identified with standard color-octet matrix elements. We analyze some numerical values extracted from charmonia production by different authors and their hierarchy in the light of HQEFT.Comment: LaTeX, 19 pages, 3 EPS figure

    Doubly heavy quark baryon spectroscopy and semileptonic decay

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    Working in the framework of a nonrelativistic quark model we evaluate the spectra and semileptonic decay widths for the ground state of doubly heavy Ξ\Xi and Ω\Omega baryons. We solve the three-body problem using a variational ansatz made possible by the constraints imposed by heavy quark spin symmetry. In order to check the dependence of our resultson the inter-quark interaction we have used five different quarkquark potentials which include Coulomb and hyperfine terms coming fromone-gluon exchange, plus a confining term. Our results for the spectra are in good agreement with a previous calculation done using a Faddeev approach. For the semileptonic decay our results for the total decay widths are in a good agreement with the ones obtained within a relativistic quark model in the quark-diquark approximation.Comment: Talk given at the IVth International Conference on Quarks an Nuclear Physics (QNP06), Madrid, June 5th-10th 200

    Searching for New Physics in Leptonic Decays of Bottomonium

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    New Physics can show up in various well-known processes already studied in the Standard Model, in particular by modifying decay rates to some extent. In this work, I examine leptonic decays of Υ\Upsilon vector resonances of bottomonium below BBˉB\bar{B} production, subsequent to a magnetic dipole radiative structural transition of the vector resonance yielding a pseudoscalar continuum state, searching for the existence of a light Higgs-like neutral boson that would imply a slight but experimentally measurable breaking of lepton universality.Comment: LaTeX, 12 pages, 1 EPS figur

    Fragmentation production of doubly heavy baryons

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    Baryons with a single heavy quark are being studied experimentally at present. Baryons with two units of heavy flavor will be abundantly produced not only at future colliders, but also at existing facilities. In this paper we study the production via heavy quark fragmentation of baryons containing two heavy quarks at the Tevatron, the LHC, HERA, and the NLC. The production rate is woefully small at HERA and at the NLC, but significant at pppp and ppˉp\bar{p} machines. We present distributions in various kinematical variables in addition to the integrated cross sections at hadron colliders.Comment: 13 pages, macro package epsfig needed, 6 .eps figure files in a separate uuencoded, compressed and tarred file; complete paper available at http://www.physics.carleton.ca/~mad/papers/paper.p

    Performance of the Fully Digital FPGA-based Front-End Electronics for the GALILEO Array

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    In this work we present the architecture and results of a fully digital Front End Electronics (FEE) read out system developed for the GALILEO array. The FEE system, developed in collaboration with the Advanced Gamma Tracking Array (AGATA) collaboration, is composed of three main blocks: preamplifiers, digitizers and preprocessing electronics. The slow control system contains a custom Linux driver, a dynamic library and a server implementing network services. The digital processing of the data from the GALILEO germanium detectors has demonstrated the capability to achieve an energy resolution of 1.53 per mil at an energy of 1.33 MeV.Comment: 5 pages, 6 figures, preprint version of IEEE Transactions on Nuclear Science paper submitted for the 19th IEEE Real Time Conferenc
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