Unemployment, Disequilibrium, and the Short Run Phillips Curve: An Econometric Approach

The paper specifies a disequilibrium model for the aggregate labor market consisting of demand and supply functions for labor, an adjustment equation for wages as well as for prices, a transactions equation and, finally, an equation that relates measured unemployment to vacancies and to excess demand. The model has a more sophisticated treatment of dynamics than earlier disequilibrium models, and uses measured unemployment as an endogenous variable. Two of the error terms are assumed to be serially correlated and the coefficients are estimated by maximum likelihood. The parameter estimates and the goodness-of-fit are satisfactory and the model's implications for the behavior of several important variables are sensible. Excess demand estimates computed in various ways are reasonable. The model is used to estimate the natural rate of unemployment as well as a short run Phillips curve. Finally, the stability properties ofthe model are analyzed by considering the eigenvalues of the system; they are found to have moduli less than one.

A general solution in the Newtonian limit of f(R)- gravity

We show that any analytic $f(R)$-gravity model, in the metric approach, presents a weak field limit where the standard Newtonian potential is corrected by a Yukawa-like term. This general result has never been pointed out but often derived for some particular theories. This means that only $f(R)=R$ allows to recover the standard Newton potential while this is not the case for other relativistic theories of gravity. Some considerations on the physical consequences of such a general solution are addressed.Comment: 5 page

The Conflict Between Equilibrium and Disequilibrium Theories: The Case of the U.S. Labor Market

A fundamental controversy in labor economics is whether unemployment is better viewed as an equilibrium or disequilibrium phenomenon. The authors contend that answers to policy problems related to unemployment will depend on which of the two characterizations of the labor market is accepted. They note the effects of inflation, taxes, and unionization on unemployment and describe those factors\u27 effects on the equilibrium/disequilibrium question by presenting both equilibrium and disequilibrium models of the U.S. labor market.https://research.upjohn.org/up_press/1115/thumbnail.jp

Advanced magneto-optical microscopy: Imaging from picoseconds to centimeters - imaging spin waves and temperature distributions (invited)

© 2016 Author(s).Recent developments in the observation of magnetic domains and domain walls by wide-field optical microscopy based on the magneto-optical Kerr, Faraday, Voigt, and Gradient effect are reviewed. Emphasis is given to the existence of higher order magneto-optical effects for advanced magnetic imaging. Fundamental concepts and advances in methodology are discussed that allow for imaging of magnetic domains on various length and time scales. Time-resolved imaging of electric field induced domain wall rotation is shown. Visualization of magnetization dynamics down to picosecond temporal resolution for the imaging of spin-waves and magneto-optical multi-effect domain imaging techniques for obtaining vectorial information are demonstrated. Beyond conventional domain imaging, the use of a magneto-optical indicator technique for local temperature sensing is shown

Gravitational lensing in fourth order gravity

Gravitational lensing is investigated in the weak field limit of fourth order gravity in which the Lagrangian of the gravitational field is modified by replacing the Ricci scalar curvature R with an analytical expression $f(R)$. Considering the case of a pointlike lens, we study the behaviour of the deflection angle in the case of power law Lagrangians, i.e. with f(R) = f_0 R^n. In order to investigate possible detectable signatures, the position of the Einstein ring and the solutions of the lens equation are evaluated considering the change with respect to the standard case. Effects on the amplification of the images and the Paczynski curve in microlensing experiments are also estimated.Comment: 10 pages, 3 figures, accepted for publication on Physical Review

Is There Chronic Excess Supply of Labor? Designing a Statistical Test

In this paper we present and implement a statistical test of the hypothesis that the labor market has chronic excess supply. The procedure is to estimate a disequilibrium labor market model, and construct a test statistic based on the unconditional probability that there is excess supply each period. We find that the data reject the hypothesis of chronic excess supply. Hence, one cannot assume that all observations lie on the demand curve.