Tension in the Recent Type Ia Supernovae Datasets

In the present work, we investigate the tension in the recent Type Ia supernovae (SNIa) datasets Constitution and Union. We show that they are in tension not only with the observations of the cosmic microwave background (CMB) anisotropy and the baryon acoustic oscillations (BAO), but also with other SNIa datasets such as Davis and SNLS. Then, we find the main sources responsible for the tension. Further, we make this more robust by employing the method of random truncation. Based on the results of this work, we suggest two truncated versions of the Union and Constitution datasets, namely the UnionT and ConstitutionT SNIa samples, whose behaviors are more regular.Comment: 14 pages, 8 figures, 9 tables, revtex4; v2: discussions added, Phys. Lett. B in press; v3: published versio

Revisiting the Cosmological Constraints on the Interacting Dark Energy Models

In this work, we consider the cosmological constraints on the interacting dark energy models. We generalize the models considered previously by Guo {\it et al.}, Costa and Alcaniz, and try to discuss two general types of models: type I models are characterized by $\rho_{_X}/\rho_m=f(a)$ and $f(a)$ can be any function of scale factor $a$, whereas type II models are characterized by $\rho_m=\rho_{m0}\,a^{-3+\epsilon(a)}$ and $\epsilon(a)$ can be any function of $a$. We obtain the cosmological constraints on the type I and II models with power-law, CPL-like, logarithmic $f(a)$ and $\epsilon(a)$ by using the latest observational data.Comment: 15 pages, 1 table, 6 figures, revtex4; v2: discussions added, Phys. Lett. B in press; v3: published versio

The China Puzzle: Theory and Evidence on the Behavior of Chinese Exports during the 2008-2009 Global Financial Crisis

Many studies link the recent collapse in trade during the 2008-09 financial crisis to a decrease in the demand for durable and investment goods in crisis-hit countries. Thus, a remarkable feature of the recent collapse in international trade is that China’s export sectors – for which the crisis-hit U.S. and Europe are the primary destinations – appear much less affected than their counterparts in other exporting countries. This paper explains the puzzle by documenting a new stylized fact: China’s processing exports fell much less than ordinary trade during the 2008-09 financial crisis, even conditioning on industry and demand in the destination country. It then investigates a range of explanations for the special behavior of processing trade