A Simple Feasible Alternative Procedure to Estimate Models with High-Dimensional Fixed Effects

In this paper we describe an alternative iterative approach for the estimation of linear regression models with high-dimensional fixed-effects such as large employer-employee data sets. This approach is computationally intensive but imposes minimum memory requirements. We also show that the approach can be extended to non-linear models and potentially to more than two high dimensional fixed effects.high dimensional fixed effects, linked employer-employee data

3C273 variability at 7 mm: Evidences of shocks and precession in the jet

We report 4 years of observations of 3C273 at 7 mm obtained with the Itapetinga Radiotelescope, in Brazil, between 2009 and 2013. We detected a flare in 2010 March, when the flux density increased by 50% and reached 35 Jy. After the flare, the flux density started to decrease and reached values lower than 10 Jy. We suggest that the 7 mm flare is the radio counterpart of the $\gamma$-ray flare observed by Fermi/LAT in 2009 September, in which the flux density at high energies reached a factor of fifty of its average value. A delay of 170 days between the radio and $\gamma$-ray flares was revealed using the Discrete Correlation Function (DCF) that can be interpreted in the context of a shock model, in which each flare corresponds to the formation of a compact superluminal component that expands and becomes optically thin at radio frequencies at latter epochs. The difference in flare intensity between frequencies and at a different times, is explained as a consequence of an increase in the Doppler factor $\delta$, as predicted by the 16 year precession model proposed by Abraham & Romero, which has a large effect on boosting at high frequencies while does not affect too much the observed optically thick radio emission. We discuss other observable effects of the variation in $\delta$, as the increase in the formation rate of superluminal components, the variations in the time delay between flares and the periodic behaviour of the radio light curve that we found compatible with changes in the Doppler factor.Comment: 9 pages, 8 figure

Real Wages and the Business Cycle: Accounting for Worker and Firm Heterogeneity

Using a longitudinal matched employer-employee data set for Portugal over the 1986-2005 period, this study analyzes the heterogeneity in wages responses to aggregate labor market conditions for newly hired workers and existing workers. Accounting for both worker and firm heterogeneity, the data support the hypothesis that entry wages are much more procyclical than current wages. A one-point increase in the unemployment rate decreases wages of newly hired male workers by around 2.8% and by just 1.4% for workers in continuing jobs. Since we estimate the fixed effects, we were able to show that unobserved heterogeneity plays a non-trivial role in the cyclicality of wages. In particular, worker fixed effects of new hires and separating workers behave countercyclically, whereas firm fixed effects exhibit a procyclical pattern. Finally, the results reveal, for all workers, a wage-productivity elasticity of 1.2, slightly above the one-for-one response predicted by the Mortensen-Pissarides model.wage cyclicality, hires, firm-specific effects, compositional effects, labor productivity