The dynamic effects of currency union on trade

A currency union’s ability to increase international trade is one of the most debated questions in international macroeconomics. This paper studies the dynamics of these trade effects over time. First, empirical work with data from the European Monetary Union finds that the extensive margin of trade (entry of new firms or goods) responds several years ahead of overall trade volume and actual implementation of the monetary union. This implies a fall at the intensive margin (previously traded goods) in the run-up to EMU. A dynamic stochastic general equilibrium model of trade studies the announcement of a future monetary union as a news shock lowering future trade costs, and finds that the early entry of new firms in anticipation is explainable as a rational forward-looking response under certain conditions. Required elements are sunk costs of exporting and ex-ante heterogeneity among firms. The findings help identify which types of trading frictions are reduced by adopting a currency union. Findings also indicate that a significant fraction of the welfare gains from a monetary union are based upon expectations for the future, so that continued gains depend upon long-term credibility of the union

Free wake analysis of hover performance using a new influence coefficient method

A new approach to the prediction of helicopter rotor performance using a free wake analysis was developed. This new method uses a relaxation process that does not suffer from the convergence problems associated with previous time marching simulations. This wake relaxation procedure was coupled to a vortex-lattice, lifting surface loads analysis to produce a novel, self contained performance prediction code: EHPIC (Evaluation of Helicopter Performance using Influence Coefficients). The major technical features of the EHPIC code are described and a substantial amount of background information on the capabilities and proper operation of the code is supplied. Sample problems were undertaken to demonstrate the robustness and flexibility of the basic approach. Also, a performance correlation study was carried out to establish the breadth of applicability of the code, with very favorable results

On Conditional Statistics in Scalar Turbulence: Theory vs. Experiment

We consider turbulent advection of a scalar field T(\B.r), passive or active, and focus on the statistics of gradient fields conditioned on scalar differences $\Delta T(R)$ across a scale $R$. In particular we focus on two conditional averages $\langle\nabla^2 T\big|\Delta T(R)\rangle$ and $\langle|\nabla T|^2\big|\Delta T(R) \rangle$. We find exact relations between these averages, and with the help of the fusion rules we propose a general representation for these objects in terms of the probability density function $P(\Delta T,R)$ of $\Delta T(R)$. These results offer a new way to analyze experimental data that is presented in this paper. The main question that we ask is whether the conditional average $\langle\nabla^2 T\big| \Delta T(R)\rangle$ is linear in $\Delta T$. We show that there exists a dimensionless parameter which governs the deviation from linearity. The data analysis indicates that this parameter is very small for passive scalar advection, and is generally a decreasing function of the Rayleigh number for the convection data.Comment: Phys. Rev. E, Submitted. REVTeX, 10 pages, 5 figs. (not included) PS Source of the paper with figure available at http://lvov.weizmann.ac.il/onlinelist.html#unpub

POTENTIAL BENEFITS OF RICE VARIETY AND WATER MANAGEMENT IMPROVEMENTS IN THE TEXAS GULF COAST

The welfare benefits from potential rice yield-enhancing and water-saving research programs and their distributional implications under alternative farm program provisions are compared. This is done in an ex ante surplus maximization framework by using a multiregional, price endogenous mathematical programming model of U.S. agriculture. The simulation results indicate that government price support policies have profound impacts on the distribution of research benefits and distort interest group incentives and rankings for allocation of resources to research.Agricultural and Food Policy, Research and Development/Tech Change/Emerging Technologies,

A Simple Passive Scalar Advection-Diffusion Model

This paper presents a simple, one-dimensional model of a randomly advected passive scalar. The model exhibits anomalous inertial range scaling for the structure functions constructed from scalar differences. The model provides a simple computational test for recent ideas regarding closure and scaling for randomly advected passive scalars. Results suggest that high order structure function scaling depends on the largest velocity eddy size, and hence scaling exponents may be geometry-dependent and non-universal.Comment: 30 pages, 11 figure

The Constraints and Spectra of a Deformed Quantum Mechanics

We examine a deformed quantum mechanics in which the commutator between coordinates and momenta is a function of momenta. The Jacobi identity constraint on a two-parameter class of such modified commutation relations (MCR's) shows that they encode an intrinsic maximum momentum; a sub-class of which also imply a minimum position uncertainty. Maximum momentum causes the bound state spectrum of the one-dimensional harmonic oscillator to terminate at finite energy, whereby classical characteristics are observed for the studied cases. We then use a semi-classical analysis to discuss general concave potentials in one dimension and isotropic power-law potentials in higher dimensions. Among other conclusions, we find that in a subset of the studied MCR's, the leading order energy shifts of bound states are of opposite sign compared to those obtained using string-theory motivated MCR's, and thus these two cases are more easily distinguishable in potential experiments.Comment: 30 pages inclusive of 7 figure

Energy Facility Siting: Recent Models of Reform

This comment first defines the energy-environment dilemma which frames the issues of energy facility siting. The comment then compares and evaluates the relative strengths and weaknesses of fast-track siting and one-stop siting. The comment concludes that, in an effort to expedite the siting process and to increase domestic energy production, the Reagan Administration should adopt a federal policy favoring one-stop siting