297 research outputs found

    Dilemmas of Structural Adjustment and Environmental Policies under Instability

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    Cataloged from PDF version of article.The Turkish structural adjustment since 1980 has been associated with chronic instability. Since the late 1980s, the weaknesses in the fiscal system and the premature external liberalization emerge as the main factors hindering the passage toward stable growth. Enforced and erratic distributional changes and relative stagnation of capital accumulation have undermined the growth potential of the economy. Further, it is demonstrated that existing market structures may negate environmental policies based on market incentives. These observations, as well as those on the interactions of the market system and the environment, create strong arguments in favor of an active state

    Turkey, 1980-2000: Financial Liberalization, Macroeconomic (In)Stability, and Patterns of Distribution

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    This chapter examines the facts and processes characterizing the dynamic macroeconomic adjustments in Turkey since the start of its reforms toward global integration. The study is organized as follows. Section 2 focuses on the analytics of macro adjustments of the two distinct (i.e., 1980-1988/1989 and 1989-2000) phases of liberalization. Section 3 quantifies the macro adjustments via a set of decomposition exercises and traces the evolution of real output and sources of aggregate demand. Microlevel adjustments and related decomposition exercises, in turn, are investigated in Section 4 for the manufacturing sector. The distributional effects of liberalization of commodity trade and finance are summarized in Section 5, and Section 6 gives a conclusion. © Oxford University Press, 2013

    Longitudinal Structure Functions in Decaying and Forced Turbulence

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    In order to reliably compute the longitudinal structure functions in decaying and forced turbulence, local isotropy is examined with the aid of the isotropic expression of the incompressible conditions for the second and third order structure functions. Furthermore, the Karman-Howarth-Kolmogorov relation is investigated to examine the effects of external forcing and temporally decreasing of the second order structure function. On the basis of these investigations, the scaling range and exponents ζn\zeta_n of the longitudinal structure functions are determined for decaying and forced turbulence with the aid of the extended-self-similarity (ESS) method. We find that ζn\zeta_n's are smaller, for n4n \geq 4, in decaying turbulence than in forced turbulence. The reasons for this discrepancy are discussed. Analysis of the local slopes of the structure functions is used to justify the ESS method.Comment: 15 pages, 16 figure

    Magnetars in the Metagalaxy: An Origin for Ultra High Energy Cosmic Rays in the Nearby Universe

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    I show that the relativistic winds of newly born magnetars with khz initial spin rates, occurring in all normal galaxies, can accelerate ultrarelativistic light ions with an E^{-1} injection spectrum, steepening to E^{-2} at higher energies, with an upper cutoff above 10^{21} eV. Interactions with the CMB yield a spectrum in good accord with the observed spectrum of Ultra-High Energy Cosmic Rays (UHECR), if ~ 5-10% of the magnetars are born with voltages sufficiently high to accelerate the UHECR. The form the spectrum spectrum takes depends on the gravitational wave losses during the magnetars' early spindown - pure electromagnetic spindown yields a flattening of the E^3 J(E) spectrum below 10^{20} eV, while a moderate GZK ``cutoff'' appears if gravitational wave losses are strong enough. I outline the physics such that the high energy particles escape with small energy losses from a magnetar's natal supernova, including Rayleigh-Taylor ``shredding'' of the supernova envelope, expansion of a relativistic blast wave into the interstellar medium, acceleration of the UHE ions through surf-riding in the electromgnetic fields of the wind, and escape of the UHE ions in the rotational equator with negligible radiation loss. The abundance of interstellar supershells and unusually large supernova remnants suggests that most of the initial spindown energy is radiated in khz gravitational waves for several hours after each supernova, with effective strains from sources at typical distances ~ 3 x 10^{-21}. Such bursts of gravitational radiation should correlate with bursts of ultra-high energy particles. The Auger experiment should see such bursts every few years.Comment: 49 pages, 2 Figures, LaTeX (aastex, epsfig, graphicx, float), to be published June 1, 2003 in the ApJ. Corrected discussion of electromagnetic surf-riding as the acceleration mechanism and more typos, and reference

    Statistics of Dissipation and Enstrophy Induced by a Set of Burgers Vortices

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    Dissipation and enstropy statistics are calculated for an ensemble of modified Burgers vortices in equilibrium under uniform straining. Different best-fit, finite-range scaling exponents are found for locally-averaged dissipation and enstrophy, in agreement with existing numerical simulations and experiments. However, the ratios of dissipation and enstropy moments supported by axisymmetric vortices of any profile are finite. Therefore the asymptotic scaling exponents for dissipation and enstrophy induced by such vortices are equal in the limit of infinite Reynolds number.Comment: Revtex (4 pages) with 4 postscript figures included via psfi

    Dynamics of vortex tangle without mutual friction in superfluid 4^4He

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    A recent experiment has shown that a tangle of quantized vortices in superfluid 4^4He decayed even at mK temperatures where the normal fluid was negligible and no mutual friction worked. Motivated by this experiment, this work studies numerically the dynamics of the vortex tangle without the mutual friction, thus showing that a self-similar cascade process, whereby large vortex loops break up to smaller ones, proceeds in the vortex tangle and is closely related with its free decay. This cascade process which may be covered with the mutual friction at higher temperatures is just the one at zero temperature Feynman proposed long ago. The full Biot-Savart calculation is made for dilute vortices, while the localized induction approximation is used for a dense tangle. The former finds the elementary scenario: the reconnection of the vortices excites vortex waves along them and makes them kinked, which could be suppressed if the mutual friction worked. The kinked parts reconnect with the vortex they belong to, dividing into small loops. The latter simulation under the localized induction approximation shows that such cascade process actually proceeds self-similarly in a dense tangle and continues to make small vortices. Considering that the vortices of the interatomic size no longer keep the picture of vortex, the cascade process leads to the decay of the vortex line density. The presence of the cascade process is supported also by investigating the classification of the reconnection type and the size distribution of vortices. The decay of the vortex line density is consistent with the solution of the Vinen's equation which was originally derived on the basis of the idea of homogeneous turbulence with the cascade process. The obtained result is compared with the recent Vinen's theory.Comment: 16 pages, 16 figures, submitted to PR

    Finite time singularities in a class of hydrodynamic models

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    Models of inviscid incompressible fluid are considered, with the kinetic energy (i.e., the Lagrangian functional) taking the form Lkαvk2d3k{\cal L}\sim\int k^\alpha|{\bf v_k}|^2d^3{\bf k} in 3D Fourier representation, where α\alpha is a constant, 0<α<10<\alpha< 1. Unlike the case α=0\alpha=0 (the usual Eulerian hydrodynamics), a finite value of α\alpha results in a finite energy for a singular, frozen-in vortex filament. This property allows us to study the dynamics of such filaments without the necessity of a regularization procedure for short length scales. The linear analysis of small symmetrical deviations from a stationary solution is performed for a pair of anti-parallel vortex filaments and an analog of the Crow instability is found at small wave-numbers. A local approximate Hamiltonian is obtained for the nonlinear long-scale dynamics of this system. Self-similar solutions of the corresponding equations are found analytically. They describe the formation of a finite time singularity, with all length scales decreasing like (tt)1/(2α)(t^*-t)^{1/(2-\alpha)}, where tt^* is the singularity time.Comment: LaTeX, 17 pages, 3 eps figures. This version is close to the journal pape

    Determination of absolute neutrino masses from Z-bursts

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    Ultrahigh energy neutrinos (UHE\nu) scatter on relic neutrinos (R\nu) producing Z bosons, which can decay hadronically producing protons (Z-burst). We compare the predicted proton spectrum with the observed ultrahigh energy cosmic ray (UHECR) spectrum and determine the mass of the heaviest R\nu via a maximum likelihood analysis. Our prediction depends on the origin of the power-like part of the UHECR spectrum: m_\nu=2.75^{+1.28}_{-0.97} eV for Galactic halo and 0.26^{+0.20}_{-0.14} eV for extragalactic (EG) origin. The necessary UHE\nu flux should be detected in the near future.Comment: slight rewording, revised neutrino fluxes, conclusions unchanged, version to appear in Phys. Rev. Let

    Ultra-High Energy Cosmic Rays, Superheavy Long-Living Particles, and Matter Creation after Inflation

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    The highest energy cosmic rays, above the Greisen-Zatsepin-Kuzmin cut-off of cosmic ray spectrum, may be produced in decays of superheavy long-living X-particles. We conjecture that these particles may be produced naturally in the early Universe from vacuum fluctuations during inflation and may constitute a considerable fraction of Cold Dark Matter. We predict a new cut-off in the UHE cosmic ray spectrum E_{cut-off} < m_inflaton \approx 10^{13} GeV, the exact position of the cut-off and the shape of the cosmic ray spectrum beyond the GZK cut-off being determined by the QCD quark/gluon fragmentation. The Pierre Auger Project installation might discover this phenomenon.Comment: LaTeX, 8 page
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