18,249 research outputs found

    Trust in the US-EU fruit and vegetable chain: Do US exporters understand EU importers?

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    Research on organizational and inter organizational trust has become an important field in management and marketing literature, as it is perceived as a pivotal aspect of business transactions. However, clarifications are still needed on the issue of whom we trust; is the person whom we are trading with trusted, or the organization, or just the product‐quality? Not only has this question not been answered within this field of research, neither have cultural differences have been described to any great extent. Additionally, if the perceived factors important to establish trusting relationships may or may not be the same on the buyers and the sellers side in international business transaction in food chains. The primary objective of this research study therefore is to identify how well US exporters understand the elements of trust that establish strong relationships with EU importers. The Analytical Hierarchy Process was used to evaluate the importance of different trust elements in interviews conducted with US exporters and EU importers of fruits and vegetables. Results are compared, providing both a picture of the important facets of trust, as well as whether the partners understand the perspectives of the other partner

    Mode-sum regularization of the scalar self-force: Formulation in terms of a tetrad decomposition of the singular field

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    We examine the motion in Schwarzschild spacetime of a point particle endowed with a scalar charge. The particle produces a retarded scalar field which interacts with the particle and influences its motion via the action of a self-force. We exploit the spherical symmetry of the Schwarzschild spacetime and decompose the scalar field in spherical-harmonic modes. Although each mode is bounded at the position of the particle, a mode-sum evaluation of the self-force requires regularization because the sum does not converge: the retarded field is infinite at the position of the particle. The regularization procedure involves the computation of regularization parameters, which are obtained from a mode decomposition of the Detweiler-Whiting singular field; these are subtracted from the modes of the retarded field, and the result is a mode-sum that converges to the actual self-force. We present such a computation in this paper. There are two main aspects of our work that are new. First, we define the regularization parameters as scalar quantities by referring them to a tetrad decomposition of the singular field. Second, we calculate four sets of regularization parameters (denoted schematically by A, B, C, and D) instead of the usual three (A, B, and C). As proof of principle that our methods are reliable, we calculate the self-force acting on a scalar charge in circular motion around a Schwarzschild black hole, and compare our answers with those recorded in the literature.Comment: 38 pages, 2 figure

    Interplay of size and Landau quantizations in the de Haas-van Alphen oscillations of metallic nanowires

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    We examine the interplay between size quantization and Landau quantization in the De Haas-Van Alphen oscillations of clean, metallic nanowires in a longitudinal magnetic field for `hard' boundary conditions, i.e. those of an infinite round well, as opposed to the `soft' parabolically confined boundary conditions previously treated in Alexandrov and Kabanov (Phys. Rev. Lett. {\bf 95}, 076601 (2005) (AK)). We find that there exist {\em two} fundamental frequencies as opposed to the one found in bulk systems and the three frequencies found by AK with soft boundary counditions. In addition, we find that the additional `magic resonances' of AK may be also observed in the infinite well case, though they are now damped. We also compare the numerically generated energy spectrum of the infinite well potential with that of our analytic approximation, and compare calculations of the oscillatory portions of the thermodynamic quantities for both models.Comment: Title changed, paper streamlined on suggestion of referrees, typos corrected, numerical error in figs 2 and 3 corrected and final result simplified -- two not three frequencies (as in the previous version) are observed. Abstract altered accordingly. Submitted to Physical Review

    Nuclear alpha-clustering, superdeformation, and molecular resonances

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    Nuclear alpha-clustering has been the subject of intense study since the advent of heavy-ion accelerators. Looking back for more than 40 years we are able today to see the connection between quasimolecular resonances in heavy-ion collisions and extremely deformed states in light nuclei. For example superdeformed bands have been recently discovered in light N=Z nuclei such as 36^{36}Ar, 40^{40}Ca, 48^{48}Cr, and 56^{56}Ni by γ\gamma-ray spectroscopy. The search for strongly deformed shapes in N=Z nuclei is also the domain of charged-particle spectroscopy, and our experimental group at IReS Strasbourg has studied a number of these nuclei with the charged particle multidetector array {\sc Icare} at the {\sc Vivitron} Tandem facility in a systematical manner. Recently the search for γ\gamma-decays in 24^{24}Mg has been undertaken in a range of excitation energies where previously nuclear molecular resonances were found in 12^{12}C+12^{12}C collisions. The breakup reaction 24^{24}Mg+12+^{12}C has been investigated at Elab_{lab}(24^{24}Mg) = 130 MeV, an energy which corresponds to the appropriate excitation energy in 24^{24}Mg for which the 12^{12}C+12^{12}C resonance could be related to the breakup resonance. Very exclusive data were collected with the Binary Reaction Spectrometer in coincidence with {\sc Euroball IV} installed at the {\sc Vivitron}.Comment: 10 pages, 4 eps figures included. Invited Talk 10th Nuclear Physics Workshop Marie and Pierre Curie, Kazimierz Dolny Poland, Sep. 24-28, 2003; To be published in International Journal of Modern Physics

    Chiral density waves in quark matter within the Nambu--Jona-Lasinio model in an external magnetic field

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    A possibility of formation of static dual scalar and pseudoscalar density wave condensates in dense quark matter is considered for the Nambu--Jona-Lasinio model in an external magnetic field. Within a mean-field approximation, the effective potential of the theory is obtained and its minima are numerically studied; a phase diagram of the system is constructed. It is shown that the presence of a magnetic field favors the formation of spatially inhomogeneous condensate configurations at low temperatures and arbitrary non-zero values of the chemical potential.Comment: 13 pages, 4 figure

    On the equivalence principle and gravitational and inertial mass relation of classical charged particles

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    We show that the locally constant force necessary to get a stable hyperbolic motion regime for classical charged point particles, actually, is a combination of an applied external force and of the electromagnetic radiation reaction force. It implies, as the strong Equivalence Principle is valid, that the passive gravitational mass of a charged point particle should be slight greater than its inertial mass. An interesting new feature that emerges from the unexpected behavior of the gravitational and inertial mass relation, for classical charged particles, at very strong gravitational field, is the existence of a critical, particle dependent, gravitational field value that signs the validity domain of the strong Equivalence Principle. For electron and proton, these critical field values are gc4.8×1031m/s2g_{c}\simeq 4.8\times 10^{31}m/s^{2} and gc8.8×1034m/s2g_{c}\simeq 8.8\times 10^{34}m/s^{2}, respectively
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