8,554 research outputs found

    Public sector debt, fiscal deficits, and economic adjustment : a comparative study of six EMENA countries

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    The authors analyzed the experience of six countries (Algeria, Morocco, Pakistan, Portugal, Turkey, and Yugoslavia) and compared it with the experiences of Latin American countries. They conclude that some countries successfully absorbed the external shock of the 1980s by: (a) minimizing the effects of the external shock by combining external and domestic debt strategies; (b) adjusting their fiscal deficits; (c) experiencing a positive external shock; and (d) fostering growth by stimulating export growth and developing domestic financial markets. No single country fully implemented this strategy; those most successful in doing so were Morocco, Portugal, and Turkey. Their experience contrasts with that of some Latin American countries that experienced a similar external shock but failed to undertake fiscal adjustment and financed most of their deficit through money finance - thus experiencing high inflation levels and overburdening their private sector. In some respects, Yugoslavia had the same experience.Environmental Economics&Policies,Economic Theory&Research,Strategic Debt Management,Economic Stabilization,Public Sector Economics&Finance

    Displacement Profile of Charge Density Waves and Domain Walls at Critical Depinning

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    The influence of a strong surface potential on the critical depinning of an elastic system driven in a random medium is considered. If the surface potential prevents depinning completely the elastic system shows a parabolic displacement profile. Its curvature C\mathcal{C} exhibits at zero temperature a pronounced rhombic hysteresis curve of width 2fc2f_c with the bulk depinning threshold fcf_c. The hysteresis disappears at non-zero temperatures if the driving force is changed adiabatically. If the surface depins by the applied force or thermal creep, C\mathcal{C} is reduced with increasing velocity. The results apply, e.g., to driven magnetic domain walls, flux-line lattices and charge-density waves.Comment: 4 pages, 2 figure

    The Final Remnant of Binary Black Hole Mergers: Multipolar Analysis

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    Methods are presented to define and compute source multipoles of dynamical horizons in numerical relativity codes, extending previous work from the isolated and dynamical horizon formalisms in a manner that allows for the consideration of horizons that are not axisymmetric. These methods are then applied to a binary black hole merger simulation, providing evidence that the final remnant is a Kerr black hole, both through the (spatially) gauge-invariant recovery of the geometry of the apparent horizon, and through a detailed extraction of quasinormal ringing modes directly from the strong-field region.Comment: 12 pages, 13 figures. Published version. Some references have been added and reordered, and the figures cleaned up

    Computing the merger of black-hole binaries: the IBBH problem

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    Gravitational radiation arising from the inspiral and merger of binary black holes (BBH's) is a promising candidate for detection by kilometer-scale interferometric gravitational wave observatories. This paper discusses a serious obstacle to searches for such radiation and to the interpretation of any observed waves: the inability of current computational techniques to evolve a BBH through its last ~10 orbits of inspiral (~100 radians of gravitational-wave phase). A new set of numerical-relativity techniques is proposed for solving this ``Intermediate Binary Black Hole'' (IBBH) problem: (i) numerical evolutions performed in coordinates co-rotating with the BBH, in which the metric coefficients evolve on the long timescale of inspiral, and (ii) techniques for mathematically freezing out gravitational degrees of freedom that are not excited by the waves.Comment: 6 pages RevTe

    In-Chain Tunneling Through Charge-Density Wave Nanoconstrictions and Break-Junctions

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    We have fabricated longitudinal nanoconstrictions in the charge-density wave conductor (CDW) NbSe3_{3} using a focused ion beam and using a mechanically controlled break-junction technique. Conductance peaks are observed below the TP1_{P1}=145=145 K and TP2_{P2}=59=59 K CDW transitions, which correspond closely with previous values of the full CDW gaps 2Δ12\Delta_{1} and 2Δ22\Delta_{2} obtained from photo-emission. These results can be explained by assuming CDW-CDW tunneling in the presence of an energy gap corrugation ϵ2\epsilon_{2} comparable to Δ2\Delta_{2}, which eliminates expected peak at Δ1+Δ2\Delta_{1}+\Delta_{2}. The nanometer length-scales our experiments imply indicate that an alternative explanation based on tunneling through back-to-back CDW-normal junctions is unlikely.Comment: 5 pages, 3 figures, submitted to physical review letter

    Effects of cryoprotectant concentration and cooling rate on vitrification of aqueous solutions

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    Vitrification of aqueous cryoprotectant mixtures is essential in cryopreservation of proteins and other biological samples. We report systematic measurements of critical cryoprotective agent (CPA) concentrations required for vitrification during plunge cooling from T=295 K to T=77 K in liquid nitrogen. Measurements on fourteen common CPAs including alcohols (glycerol, methanol, isopropanol), sugars (sucrose, xylitol, dextrose, trehalose), PEGs (ethylene glycol, PEG 200, PEG 2 000, PEG 20 000), glycols (DMSO, MPD), and salt (NaCl) were performed for volumes ranging over four orders of magnitude from ~nL to 20 mkL, and covering the range of interest in protein crystallography. X-ray diffraction measurements on aqueous glycerol mixtures confirm that the polycrystalline-to-vitreous transition occurs within a span of less than 2% w/v in CPA concentration, and that the form of polycrystalline ice (hexagonal or cubic) depends on CPA concentration and cooling rate. For most of the studied cryoprotectants, the critical concentration decreases strongly with volume in the range from ~5 mkL to ~0.1 mkL, typically by a factor of two. By combining measurements of the critical concentration versus volume with cooling time versus volume, we obtain the function of greatest intrinsic physical interest: the critical CPA concentration versus cooling rate during flash cooling. These results provide a basis for more rational design of cryoprotective protocols, and should yield insight into the physics of glass formation in aqueous mixtures.Comment: 8 pages, 6 jpg figure, 2 table

    Central Exclusive Di-jet Production at the Tevatron

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    We perform a phenomenological analysis of dijet production in double pomeron exchange at the Tevatron. We find that the CDF Run I results do not rule out the presence of an exclusive dijet component, as predicted by Khoze, Martin and Ryskin (KMR). With the high statistics CDF Run II data, we predict that an exclusive component at the level predicted by KMR may be visible, although the observation will depend on accurate modelling of the inclusive double pomeron exchange process. We also compare to the predictions of the DPEMC Monte Carlo, which contains a non-perturbative model for the central exclusive process. We show that the perturbative model of KMR gives different predictions for the di-jet ET dependence in the high di-jet mass fraction region than non-perturbative models.Comment: 17 pages, 15 figure

    Distortion of Schwarzschild-anti-de Sitter black holes to black strings

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    Motivated by the existence of black holes with various topologies in four-dimensional spacetimes with a negative cosmological constant, we study axisymmetric static solutions describing any large distortions of Schwarzschild-anti-de Sitter black holes parametrized by the mass mm. Under the approximation such that mm is much larger than the anti-de Sitter radius, it is found that a cylindrically symmetric black string is obtained as a special limit of distorted spherical black holes. Such a prolonged distortion of the event horizon connecting a Schwarzschild-anti-de Sitter black hole to a black string is allowed without violating both the usual black hole thermodynamics and the hoop conjecture for the horizon circumference.Comment: 13 pages, accepted for publication in Physical Review

    The Cleaving of House and Home: A Lacanian Analysis of Architectural Aesthetics

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    Drawing on Lacanian psychoanalysis and digital media studies, this thesis explores the radical disconnect between the home as a fantasmatic object of desire and the house as the space in which the fantasy of home is staged. By analyzing the house as a prosthetic replacement for our originary home (the womb), the aim is to uncover how architectural aesthetics of the Victorian, modern, and postmodern house respond to this irreconcilable gap, and why each aesthetic necessarily fails to create a more homely home. Considering recent trends in architecture, the thesis then examines the coincidence of the “small house” movement with the transformation of the house into a “media centre.” New digital media technologies have opened up a new virtual world to explore that radically defies and blurs our conventional understanding of interior and exterior spaces. While such technologies open up new possibilities for reimagining our relation to the house, they are also potentially disruptive and dystopic
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