Effects of spatial dispersion in near-field radiative heat transfer between two parallel metallic surfaces

We study the heat transfer between two parallel metallic semi-infinite media with a gap in the nanometer-scale range. We show that the near-field radiative heat flux saturates at distances smaller than the metal skin depth when using a local dielectric constant and investigate the origin of this effect. The effect of non-local corrections is analysed using the Lindhard-Mermin and Boltzmann-Mermin models. We find that local and non-local models yield the same heat fluxes for gaps larger than 2 nm. Finally, we explain the saturation observed in a recent experiment as a manifestation of the skin depth and show that heat is mainly dissipated by eddy currents in metallic bodies.Comment: Version without figures (8 figures in the complete version

Some Evidence on the Importance of Sticky Wages

Nominal wage stickiness is an important component of recent medium-scale structural macroeconomic models, but to date there has been little microeconomic evidence supporting the assumption of sluggish nominal wage adjustment. We present evidence on the frequency of nominal wage adjustment using data from the Survey of Income and Program Participation (SIPP) for the period 1996-1999. The SIPP provides high-frequency information on wages, employment and demographic characteristics for a large and representative sample of the US population. The main results of the analysis are as follows. 1) After correcting for measurement error, wages appear to be very sticky. In the average quarter, the probability that an individual will experience a nominal wage change is between 5 and 18 percent, depending on the samples and assumptions used. 2) The frequency of wage adjustment does not display significant seasonal patterns. 3) There is little heterogeneity in the frequency of wage adjustment across industries and occupations 4) The hazard of a nominal wage change first increases and then decreases, with a peak at 12 months. 5) The probability of a wage change is positively correlated with the unemployment rate and with the consumer price inflation rate