30,111 research outputs found

    Distribution margins, imported inputs, and the insensitivity of the CPI to exchange rates

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    Border prices of traded goods are highly sensitive to exchange rates, but the CPI and the retail prices of traded goods are more stable. Our paper decomposes the sources of this stability for twenty-one OECD countries, focusing on the important roles of distribution margins and imported inputs in transmitting exchange rate fluctuations into consumption prices. We provide rich cross-country and cross-industry details on distribution margins and their sensitivity to exchange rates, imported inputs used in different categories of consumption goods, and weights in consumption of nontradables, home tradables and imported goods. While distribution margins damp the sensitivity of consumption prices of tradable goods to exchange rates, they also lead to enhanced pass-through when nontraded goods prices are sensitive to exchange rates. Such price sensitivity arises because imported inputs are used in production of home nontradables. Calibration exercises show that, at under 5%, the United States has the lowest expected CPI sensitivity to exchange rates of all countries examined. On average, calibrated exchange rate pass-through into CPIs is expected to be closer to 15%.Exchange rate; pass through; import prices; distribution margins;

    Magnetic field effects on microwave absorbing materials

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    The objective of this program was to gather information to formulate a microwave absorber that can work in the presence of strong constant direct current (DC) magnetic fields. The program was conducted in four steps. The first step was to investigate the electrical and magnetic properties of magnetic and ferrite microwave absorbers in the presence of strong magnetic fields. This included both experimental measurements and a literature survey of properties that may be applicable to finding an appropriate absorbing material. The second step was to identify those material properties that will produce desirable absorptive properties in the presence of intense magnetic fields and determine the range of magnetic field in which the absorbers remain effective. The third step was to establish ferrite absorber designs that will produce low reflection and adequate absorption in the presence of intense inhomogeneous static magnetic fields. The fourth and final step was to prepare and test samples of such magnetic microwave absorbers if such designs seem practical

    Evidence of Skyrmion excitations about ν=1\nu =1 in n-Modulation Doped Single Quantum Wells by Inter-band Optical Transmission

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    We observe a dramatic reduction in the degree of spin-polarization of a two-dimensional electron gas in a magnetic field when the Fermi energy moves off the mid-point of the spin-gap of the lowest Landau level, ν=1\nu=1. This rapid decay of spin alignment to an unpolarized state occurs over small changes to both higher and lower magnetic field. The degree of electron spin polarization as a function of ν\nu is measured through the magneto-absorption spectra which distinguish the occupancy of the two electron spin states. The data provide experimental evidence for the presence of Skyrmion excitations where exchange energy dominates Zeeman energy in the integer quantum Hall regime at ν=1\nu=1

    Multiobjective analysis for the design and control of an electromagnetic valve actuator

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    The electromagnetic valve actuator can deliver much improved fuel efficiency and reduced emissions in spark ignition (SI) engines owing to the potential for variable valve timing when compared with cam-operated, or conventional, variable valve strategies. The possibility exists to reduce pumping losses by throttle-free operation, along with closed-valve engine braking. However, further development is required to make the technology suitable for accept- ance into the mass production market. This paper investigates the application of multiobjective optimization techniques to the conflicting objective functions inherent in the operation of such a device. The techniques are utilized to derive the optimal force–displacement characteristic for the solenoid actuator, along with its controllability and dynamic/steady state performance

    Exchange-Rate Pass-Through to Import Prices in the Euro Area

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    This paper presents an empirical analysis of transmission rates from exchange rate movements to import prices, across countries and product categories, in the euro area over the last fifteen years. Our results show that the transmission of exchange rate changes to import prices in the short run is high, although incomplete, and that it differs across industries and countries; in the long run, exchange rate pass-through is higher and close to one. We find no strong statistical evidence that the introduction of the euro caused a structural change in this transmission. Although estimated point elasticities seem to have declined since the introduction of the euro, we find little evidence of a structural break in the transmission of exchange rate movements except in the case of some manufacturing industries. And since the euro was introduced, industries producing differentiated goods have been more likely to experience reduced rates of exchange rate pass-through to import prices. Exchange rate changes continue to lead to large changes in import prices across euro-area countries.

    L^p boundedness of the wave operator for the one dimensional Schroedinger operator

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    Given a one dimensional perturbed Schroedinger operator H=-(d/dx)^2+V(x) we consider the associated wave operators W_+, W_- defined as the strong L^2 limits as s-> \pm\infty of the operators e^{isH} e^{-isH_0} We prove that the wave operators are bounded operators on L^p for all 1<p<\infty, provided (1+|x|)^2 V(x) is integrable, or else (1+|x|)V(x) is integrable and 0 is not a resonance. For p=\infty we obtain an estimate in terms of the Hilbert transform. Some applications to dispersive estimates for equations with variable rough coefficients are given.Comment: 26 page

    Microlensing and the Search for Extraterrestrial Life

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    Are microlensing searches likely to discover planets that harbor life? Given our present state of knowledge, this is a difficult question to answer. We therefore begin by asking a more narrowly focused question: are conditions on planets discovered via microlensing likely to be similar to those we experience on Earth? In this paper I link the microlensing observations to the well-known "Goldilocks Problem" (conditions on the Earth-like planets need to be "just right"), to find that Earth-like planets discovered via microlensing are likely to be orbiting stars more luminous than the sun. This means that light from the planetary system's central star may contribute a significant fraction of the baseline flux relative to the star that is lensed. Such blending of light from the lens with light from the lensed source can, in principle, limit our ability to detect these events. This turns out not to be a significant problem, however. A second consequence of blending is the opportunity to determine the spectral type of the lensed spectral type of the lensed star. This circumstance, plus the possibility that finite-source-size effects are important, implies that some meaningful follow-up observations are likely to be possible for a subset Earth-like planets discovered via microlensing. In addition, calculations indicate that reasonable requirements on the planet's density and surface gravity imply that the mass of Earth-like planets is likely to be within a factor of 15\sim 15 of an Earth mass.Comment: 15 pages, 2 figures. To be published in the Astrophysical Journa

    Semi-analytical Solution of Dirac equation in Schwarzschild Geometry

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    Separation of the Dirac equation in the spacetime around a Kerr black hole into radial and angular coordinates was done by Chandrasekhar in 1976. In the present paper, we solve the radial equations in a Schwarzschild geometry semi-analytically using Wentzel-Kramers-Brillouin approximation (in short WKB) method. Among other things, we present analytical expression of the instantaneous reflection and transmission coefficients and the radial wave functions of the Dirac particles. Complete physical parameter space was divided into two parts depending on the height of the potential well and energy of the incoming waves. We show the general solution for these two regions. We also solve the equations by a Quantum Mechanical approach, in which the potential is approximated by a series of steps and found that these two solutions agree. We compare solutions of different initial parameters and show how the properties of the scattered wave depend on these parameters.Comment: RevTex, 11 Latex pages and 12 Figures ; Classical and Quantum Gravity (in Press) (1999

    Exciton mediated one phonon resonant Raman scattering from one-dimensional systems

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    We use the Kramers-Heisenberg approach to derive a general expression for the resonant Raman scattering cross section from a one-dimensional (1D) system explicitly accounting for excitonic effects. The result should prove useful for analyzing the Raman resonance excitation profile lineshapes for a variety of 1D systems including carbon nanotubes and semiconductor quantum wires. We apply this formalism to a simple 1D model system to illustrate the similarities and differences between the free electron and correlated electron-hole theories.Comment: 10 pages, 6 figure
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