Measuring the natural output gap using actual and expected output data

An output gap measure is suggested based on the Beveridge-Nelson decomposition of output using a vector-autoregressive model that includes data on actual output and on expected output obtained from surveys. The paper explains the advantages of using survey data in business cycle analysis and the gap is provided economic meaning by relating it to the natural level of output defined in Dynamic Stochastic General Equilibrium models. The measure is applied to quarterly US data over the period 1970q1-2007q4 and the resultant gap estimates are shown to have sensible statistical properties and perform well in explaining inflation in estimates of New Keynesian Phillips curves

Testing Gravity Theories In The Radiative Regime Using Pulsar Timing Arrays

General relativity has predicted the existence of gravitational waves (GW), which are waves of the distortions of space-time with two degrees of polarization and the propagation speed of light. Alternative theories predict more polarizations, up to a maximum of six, and possible deviation of propagation speed from the light speed. The present paper reviews recent proposals to test the gravity theories in the radiation regime by observing GWs using pulsar timing arrays.Comment: 4 pages, 2 figures, PULSAR CONFERENCE 2010, Chia Laguna Resort, Sardinia, Italy, 10-15 October, 201

Antipersistant Effects in the Dynamics of a Competing Population

We consider a population of agents competing for finite resources using strategies based on two channels of signals. The model is applicable to financial markets, ecosystems and computer networks. We find that the dynamics of the system is determined by the correlation between the two channels. In particular, occasional mismatches of the signals induce a series of transitions among numerous attractors. Surprisingly, in contrast to the effects of noises on dynamical systems normally resulting in a large number of attractors, the number of attractors due to the mismatched signals remains finite. Both simulations and analyses show that this can be explained by the antipersistent nature of the dynamics. Antipersistence refers to the response of the system to a given signal being opposite to that of the signal's previous occurrence, and is a consequence of the competition of the agents to make minority decisions. Thus, it is essential for stabilizing the dynamical systems.Comment: 4 pages, 6 figure