Short- and long-term impact of remarkable economic events on the growth causes of China-Germany trade in agri-food products

This paper focuses on a systematic quantitative discussion of the short- and long-term impact of remarkable economic events on international trade in a two-stage framework. Firstly, procedures based on dummy variables are proposed to detect structural breaks, types and sizes of jumps caused by such events. Then we propose to apply a hierarchical CMS (Constant Market Share) model to all sub-periods defined by the detected change points to study the short- and long-term impact of those events on growth causes. Application to China-Germany trade in agri-food products shows that China’s accession to WTO had a negative short-term impact on corresponding series. But its long-term impact on China’s export competitiveness was definitely positive. The short-term impact of the EU’s CAP (Common Agricultural Policy) reform on Germany’s exports to China was also negative. Its long-term impact on export competitiveness was sometimes positive and sometimes negative. The financial crisis of 2008 caused a significant reduction of China’s agri-food exports to Germany. But Germany’s exports to China in 2009 were not affected by the financial crisis as much.Growth causes of agri-food trade; the CMS model; the EU’s CAP reform; China’s accession to WTO; financial crisis

Determining the luminosity function of Swift long gamma-ray bursts with pseudo-redshifts

The determination of luminosity function (LF) of gamma-ray bursts (GRBs) is of an important role for the cosmological applications of the GRBs, which is however hindered seriously by some selection effects due to redshift measurements. In order to avoid these selection effects, we suggest to calculate pseudo-redshifts for Swift GRBs according to the empirical L-E_p relationship. Here, such a $L-E_p$ relationship is determined by reconciling the distributions of pseudo- and real redshifts of redshift-known GRBs. The values of E_p taken from Butler's GRB catalog are estimated with Bayesian statistics rather than observed. Using the GRB sample with pseudo-redshifts of a relatively large number, we fit the redshift-resolved luminosity distributions of the GRBs with a broken-power-law LF. The fitting results suggest that the LF could evolve with redshift by a redshift-dependent break luminosity, e.g., L_b=1.2\times10^{51}(1+z)^2\rm erg s^{-1}. The low- and high-luminosity indices are constrained to 0.8 and 2.0, respectively. It is found that the proportional coefficient between GRB event rate and star formation rate should correspondingly decrease with increasing redshifts.Comment: 5 pages, 5 figures, accepted for publication in ApJ