1,466 research outputs found

    Trade and Growth: Import-Led or Export-Led? Evidence From Japan and Korea

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    It is commonly argued that Japanese trade protection has enabled the nurturing and development internationally competitive firms. The results in our paper suggest that when it comes to TFP growth, this view of Japan is seriously erroneous. We find that lower tariffs and higher import volumes would have been particularly beneficial for Japan during the period 1964 to 1973. Our results also lead us to question whether Japanese exports were a particularly important source of productivity growth. Our findings on Japan suggest that the salutary impact of imports stems more from their contribution to competition than to intermediate inputs. Furthermore our results indicate a reason for why imports are important. Greater imports of competing products spur innovation. Our results suggest that competitive pressures and potentially learning from foreign rivals are important conduits for growth. These channels are even more important as industries converge with the market leader. This suggests that further liberalization by Japan and other East Asian countries may result in future dynamic gains. Our results thus call the views of both the World Bank and the revisionists into question and provide support for those who advocate more liberal trade policies.

    Towards a Theory of Environmental Dispute Resolution

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    Entropy measures as geometrical tools in the study of cosmology

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    Classical chaos is often characterized as exponential divergence of nearby trajectories. In many interesting cases these trajectories can be identified with geodesic curves. We define here the entropy by S=lnχ(x)S = \ln \chi (x) with χ(x)\chi(x) being the distance between two nearby geodesics. We derive an equation for the entropy which by transformation to a Ricatti-type equation becomes similar to the Jacobi equation. We further show that the geodesic equation for a null geodesic in a double warped space time leads to the same entropy equation. By applying a Robertson-Walker metric for a flat three-dimensional Euclidian space expanding as a function of time, we again reach the entropy equation stressing the connection between the chosen entropy measure and time. We finally turn to the Raychaudhuri equation for expansion, which also is a Ricatti equation similar to the transformed entropy equation. Those Ricatti-type equations have solutions of the same form as the Jacobi equation. The Raychaudhuri equation can be transformed to a harmonic oscillator equation, and it has been shown that the geodesic deviation equation of Jacobi is essentially equivalent to that of a harmonic oscillator. The Raychaudhuri equations are strong geometrical tools in the study of General Relativity and Cosmology. We suggest a refined entropy measure applicable in Cosmology and defined by the average deviation of the geodesics in a congruence.Comment: Final Versio

    Short range correlations and the isospin dependence of nuclear correlation functions

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    Pair densities and associated correlation functions provide a critical tool for introducing many-body correlations into a wide-range of effective theories. Ab initio calculations show that two-nucleon pair-densities exhibit strong spin and isospin dependence. However, such calculations are not available for all nuclei of current interest. We therefore provide a simple model, which involves combining the short and long separation distance behavior using a single blending function, to accurately describe the two-nucleon correlations inherent in existing ab initio calculations. We show that the salient features of the correlation function arise from the features of the two-body short-range nuclear interaction, and that the suppression of the pp and nn pair-densities caused by the Pauli principle is important. Our procedure for obtaining pair-density functions and correlation functions can be applied to heavy nuclei which lack ab initio calculations.Comment: 5 pages, 4 figure

    Nucleon-Nucleon Correlations, Short-Lived Excitations, and the Quarks Within

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    This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. The interpretation of measurements of the European Muon Collaboration (EMC) effect for valence quarks, a reduction in the deep inelastic scattering cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon short-range correlations (SRCs) in nuclei are focused on. This review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRCs that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein

    Nucleon-Nucleon Correlations, Short-Lived Excitations, and the Quarks Within

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    This article reviews our current understanding of how the internal quark structure of a nucleon bound in nuclei differs from that of a free nucleon. The interpretation of measurements of the European Muon Collaboration (EMC) effect for valence quarks, a reduction in the deep inelastic scattering cross-section ratios for nuclei relative to deuterium, and its possible connection to nucleon-nucleon short-range correlations (SRCs) in nuclei are focused on. This review and new analysis (involving the amplitudes of non-nucleonic configurations in the nucleus) of the available experimental and theoretical evidence shows that there is a phenomenological relation between the EMC effect and the effects of SRCs that is not an accident. The influence of strongly correlated neutron-proton pairs involving highly virtual nucleons is responsible for both effects. These correlated pairs are temporary high-density fluctuations in the nucleus in which the internal structure of the nucleons is briefly modified. This conclusion needs to be solidified by the future experiments and improved theoretical analyses that are discussed herein

    BEYOND THE BORN APPROXIMATION: A PRECISE COMPARISON OF e + p AND e − p ELASTIC SCATTERING IN THE CEBAF LARGE ACCEPTANCE

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    How well we know the structure of the proton depends on our knowledge of the form factors of the proton. The ratio of the electromagnetic form factors of the proton measured by the Rosenbluth and the polarization transfer methods differ by a factor of 3 at four momentum transfer squared (Q 2)=5.6 GeV 2. The two photon exchange (TPE) effect is the leading candidate to explain this discrepancy. The theoretical estimates of the TPE effect are model dependent so precise measurement is required to resolve this problem. The TPE effect can be measured in a model independent way by measuring the ratio of positron-proton to electron-proton elastic scattering cross-sections. We produced a simultaneously mixed electron-positron beam in the engineering test run conducted in October 2006 and measured the e + p/e − p ratio using the CEBAF large acceptance spectrometer (CLAS). Due to the luminosity constraint our kinematic coverage is limited to low Q2 and high ε (longitudinal polarization of the virtual photon). We continued our background study through GEANT4 simulation developed for the test run design in order to find more background sources and to design required shielding. The simulation is validated by using the test run data and is used further to optimize the luminosity for the final experiment. We are able to increase the luninosity by an order of magnitude for the upcoming final run. The final experiment will extend the data in high Q2 and low ε region where TPE effec
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