Granular gravitational collapse and chute flow

Inelastic grains in a flow under gravitation tend to collapse into states in which the relative normal velocities of two neighboring grains is zero. If the time scale for this gravitational collapse is shorter than inverse strain rates in the flow, we propose that this collapse will lead to the formation of ``granular eddies", large scale condensed structures of particles moving coherently with one another. The scale of these eddies is determined by the gradient of the strain rate. Applying these concepts to chute flow of granular media, (gravitationally driven flow down inclined planes) we predict the existence of a bulk flow region whose rheology is determined only by flow density. This theory yields the experimental ``Pouliquen flow rule", correlating different chute flows; it also correctly accounts for the different flow regimes observed.Comment: LaTeX2e with epl class, 7 pages, 2 figures, submitted to Europhysics Letter

Misaligned? Overvalued? The Untold Story of the Turkish Lira

There is a consensus among scholars that overvalued exchange rates result in currency crises. This paper estimates the equilibrium real exchange rate for Turkey and finds that the lira was indeed overvalued before the crises in 1994 and 2001. However, the actual real exchange rate is at present close to the equilibrium level, exposing the myth propagated by the Turkish exporters that lira’s overvaluation is responsible for Turkey’s uncompetitive exports. The paper also highlights the role for fiscal adjustment in macroeconomic stabilityTurkish lira, overvaluation, equilibrium real exchange rate, misalignment

Covariant Symplectic Structure and Conserved Charges of New Massive Gravity

We show that the symplectic current obtained from the boundary term, which arises in the first variation of a local diffeomorphism invariant action, is covariantly conserved for any gravity theory described by that action. Therefore, a Poincare invariant 2-form can be constructed on the phase space, which is shown to be closed without reference to a specific theory. Finally, we show that one can obtain a charge expression for gravity theories in various dimensions, which plays the role of the Abbott-Deser-Tekin (ADT) charge for spacetimes with non-constant curvature backgrounds, by using the diffeomorphism invariance of the symplectic 2-form. As an example, we calculate the conserved charges of some solutions of New Massive Gravity (NMG) and compare the results with the previous works.Comment: 18 pages, No figures, RevTEX4.1; ver 2: minor corrections, version accepted for publication in Physical Review

The Impact of Fed Policy Announcements on Emerging Stock Markets: Evidence from Borsa Istanbul

This paper aims to understand the impact of US nonfarm payroll announcements on emerging stock markets through concentrating on the Turkish Stock Exchange: BIST 100. We not only investigate the impact of each of the three components of the nonfarm payroll data for the whole period under consideration, but also look for possible differences among four sub-periods. A comparative analysis leads us to conclude that it is not the nonfarm payroll which significantly affect BIST 100, but the fact that it is regarded as an important indicator to foresee Fed’s policy actions that can alter the capital flows