Cosmic age, Statefinder and OmOm diagnostics in the decaying vacuum cosmology

As an extension of $\Lambda$CDM, the decaying vacuum model (DV) describes the dark energy as a varying vacuum whose energy density decays linearly with the Hubble parameter in the late-times, $\rho_\Lambda(t) \propto H(t)$, and produces the matter component. We examine the high-$z$ cosmic age problem in the DV model, and compare it with $\Lambda$CDM and the Yang-Mills condensate (YMC) dark energy model. Without employing a dynamical scalar field for dark energy, these three models share a similar behavior of late-time evolution. It is found that the DV model, like YMC, can accommodate the high-$z$ quasar APM 08279+5255, thus greatly alleviates the high-$z$ cosmic age problem. We also calculate the Statefinder $(r,s)$ and the {\it Om} diagnostics in the model. It is found that the evolutionary trajectories of $r(z)$ and $s(z)$ in the DV model are similar to those in the kinessence model, but are distinguished from those in $\Lambda$CDM and YMC. The ${\it Om}(z)$ in DV has a negative slope and its height depends on the matter fraction, while YMC has a rather flat ${\it Om}(z)$, whose magnitude depends sensitively on the coupling.Comment: 12 pages, 4 figures, with some correction

Local Protectionism and Regional Specialization: Evidence from China’s Industries

This paper uses a dynamic panel estimation method to investigate the determinants of regional specialization in China’s industries, paying particular attention to local protectionism. Less geographic concentration is found in industries where the past tax-plus-profit margins and the shares of state ownership are high, re- flecting stronger local government protection of these industries. The evidence also supports the scale-economies theory of regional specialization. Finally, the overall time trend of regional specialization of China’s industries is found to have reversed an early drop in the mid 1980s, and registered a significant increase in the later years.http://deepblue.lib.umich.edu/bitstream/2027.42/39951/3/wp565.pd