595 research outputs found

    Experimental Investigation of Supplier-Retailer Contracts: The Wholesale Price Contract

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    We examine decision making in a simple supplier-retailer wholesale price contract in the experimental economics laboratory. We observe wholesale prices and order quantities below the game-theoretical predictions. The supply chain’s efficiency is as predicted but profits are more equitably allocated. Cette étude en économie expérimentale examine les contrats de prix en gros négociés entre un détaillant et un vendeur. Nous observons que les prix et les quantités négociés sont en dessous des prévisions tirées du modèle retenue en théorie des jeux. Les résultats expérimentaux indiquent que l’efficacité de la chaîne d’approvisionnement est inférieur à 100 % tel que prédit par le modèle. Par ailleurs, les profits sont alloués de façon plus équitable que l’allocation prédite par le modèle.supply chain coordination, industrial organization, experimental economics, coordination dans la chaîne d’approvisionnement, organisation industrielle, économie expérimentale

    Microscopic study of Ca++Ca fusion

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    We investigate the fusion barriers for reactions involving Ca isotopes 40Ca+40Ca\mathrm{^{40}Ca}+\mathrm{^{40}Ca}, 40Ca+48Ca\mathrm{^{40}Ca}+\mathrm{^{48}Ca}, and 48Ca+48Ca\mathrm{^{48}Ca}+\mathrm{^{48}Ca} using the microscopic time-dependent Hartree-Fock theory coupled with a density constraint. In this formalism the fusion barriers are directly obtained from TDHF dynamics. We also study the excitation of the pre-equilibrium GDR for the 40Ca+48Ca\mathrm{^{40}Ca}+\mathrm{^{48}Ca} system and the associated γ\gamma-ray emission spectrum. Fusion cross-sections are calculated using the incoming-wave boundary condition approach. We examine the dependence of fusion barriers on collision energy as well as on the different parametrizations of the Skyrme interaction.Comment: 11 pages, 13 figure

    Microscopic Calculation of Fusion: Light to Heavy Systems

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    The density-constrained time-dependent Hartree-Fock (DC-TDHF) theory is a fully microscopic approach for calculating heavy-ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss recent applications of DC-TDHF method to fusion of light and heavy neutron-rich systems.Comment: 8 pages, 8 figure

    Fusion using time-dependent density-constrained DFT

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    We present results for calculating fusion cross-sections using a new microscopic approach based on a time-dependent density-constrained DFT calculations. The theory is implemented by using densities and other information obtained from TDDFT time-evolution of the nuclear system as constraint on the density for DFT calculations.Comment: 4 Pages, 6 Figures Proceedings of INPC 2013, to be published in EPJ Web of Conference

    Microscopic DC-TDHF study of heavy-ion potentials and fusion cross sections

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    We study heavy-ion fusion reactions at energies near the Coulomb barrier, in particular with neutron-rich radioactive ion beams. Dynamic microscopic calculations are carried out on a three-dimensional lattice using the Density-Constrained Time-Dependent Hartree-Fock (DC-TDHF) method. New results are presented for the 132^{132}Sn+40^{40}Ca system which are compared to 132^{132}Sn+48^{48}Ca studied earlier. Our theoretical fusion cross-sections agree surprisingly well with recent data measured at HRIBF. We also study the near- and sub-barrier fusion of 24,16^{24,16}O on 12^{12}C which is important to determine the composition and heating of the crust of accreting neutron stars.Comment: Talk given by . Volker E. Oberacker at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

    Heating of Micro-protrusions in Accelerating Structures

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    The thermal and field emission of electrons from protrusions on metal surfaces is a possible limiting factor on the performance and operation of high-gradient room temperature accelerator structures. We present here the results of extensive numerical simulations of electrical and thermal behavior of protrusions. We unify the thermal and field emission in the same numerical framework, describe bounds for the emission current and geometric enhancement, then we calculate the Nottingham and Joule heating terms and solve the heat equation to characterize the thermal evolution of emitters under RF electric field. Our findings suggest that, heating is entirely due to the Nottingham effect, that thermal runaway scenarios are not likely, and that high RF frequency causes smaller swings in temperature and cooler tips. We build a phenomenological model to account for the effect of space charge and show that space charge eliminates the possibility of tip melting, although near melting temperatures reached.Comment: 8 pages, 10 figure

    Dynamic Microscopic Theory of Fusion Using DC-TDHF

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    The density-constrained time-dependent Hartree-Fock (DC-TDHF) theory is a fully microscopic approach for calculating heavy-ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss recent applications of DC-TDHF method to fusion of light and heavy systems.Comment: Proceedings for the talk presented by A.S. Umar at the Nuclear Structure and Dynamics II, Opatija, Croatia, July 9-13, 201

    Budget Processes: Theory and Experimental Evidence

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    This paper studies budget processes, both theoretically and experimentally. We compare the outcomes of bottom-up and top-down budget processes. It is often presumed that a top-down budget process leads to a smaller overall budget than a bottom-up budget process. Ferejohn and Krehbiel (1987) showed theoretically that this need not be the case. We test experimentally the theoretical predictions of their work. The evidence from these experiments lends strong support to their theory, both at the aggregate and the individual subject level

    PTPN22 gene polymorphism in Takayasu's arteritis

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    Objective. Takayasu's arteritis (TA) is a chronic, rare granulomatous panarteritis of unknown aetiology involving mainly the aorta and its major branches. In this study, genetic susceptibility to TA has been investigated by screening the functional single nucleotide polymorphism (SNP) of PTPN22 gene encoding the lymphoid-specific protein tyrosine phosphatase. Methods. Totally, 181 patients with TA and 177 healthy controls are genotyped by PCR-RFLP method for the SNP rs2476601 (A/G) of PTPN22 gene. Polymorphic region was amplified by PCR and digested with Xcm I enzyme. Results. Detected frequencies of heterozygous genotype (AG) were 5.1% (9/177) in control group and 3.8% (7/181) in TA group (P = 0.61, odds ratio: 0.75, 95% CI: 0.3, 2.0). No association with angiographic type, vascular involvement or prognosis of TA was observed either. Conclusion. The distribution of PTPN22 polymorphism did not reveal any association with TA in Turkey. © The Author 2008. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved
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