3,410 research outputs found
SUNK COSTS HYSTERESIS IN SPANISH MANUFACTURING EXPORTS
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
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
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
Working in the framework of a nonrelativistic quark model we evaluate the
spectra and semileptonic decay widths for the ground state of doubly heavy
and 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
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 vector resonances of
bottomonium below 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
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 and
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
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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