Does Comparative Advantage Explain Export Patterns in China?

Revealed comparative advantage indices are calculated for China (1980-2000 period) and the Chinese provinces (1990-1998 period) and then incorporated into a reduced form export equation. The results of China’s export patterns show that China has moved from a heavy industry-oriented development strategy to a comparative advantage one, with, however, marked differences among provinces. The econometric results show that this shift had a significant impact on the exports, besides the effects of real effective exchange rate, world demand, and domestic supply.China, Export patterns, Exchange rate, Comparative advantage

A new mechanical structural damage feature index based on HHT

A new damage feature index is presented for the structural health monitoring based on Hilbert-Huang transform (HHT). The energy marginal spectrum of the dynamic signal is used to construct damage characteristic parameter, which can reflect the signal energy variation and benefit the structural damage detection. A sinusoidal wave with frequency change and a composite plate vibration experiment with pre-defined damage are designed to verify the effectiveness of characteristic parameter in damage detection. Results obtained from simulation and test show that the extracted non-model-based damage feature index is available and sensitive in damage detection of time-varying system.Peer Reviewe

Next-to-leading order QCD corrections to tZtZ associated production via the flavor-changing neutral-current couplings at hadron colliders

We present the complete next-to-leading order (NLO) QCD corrections to $tZ$ associated production induced by the model-independent $tqg$ and $tqZ$ flavor-changing neutral-current couplings at hadron colliders, respectively. Our results show that, for the $tuZ$ coupling the NLO QCD corrections can enhance the total cross sections by about 60% and 42%, and for the $tcZ$ coupling by about 51% and 43% at the Tevatron and LHC, respectively. The NLO corrections, for the $tug$ couplings, can enhance the total cross sections by about 27%, and by about 42% for the $tcg$ coupling at the LHC. We also consider the mixing effects between the $tqg$ and $tqZ$ couplings for this process, which can either be large or small depending on the values of the anomalous couplings. Besides, the NLO corrections reduce the dependence of the total cross sections on the renormalization or factorization scale significantly, which lead to increased confidence on the theoretical predictions. And we also evaluate the NLO corrections to several important kinematic distributions.Comment: Published version in Phys. Rev.

Determinations of form factors for semileptonic D→KD\rightarrow K decays and leptoquark constraints

By analyzing all existing measurements for $D\rightarrow K \ell^+ \nu_{\ell}$ ( $\ell=e,\ \mu$ ) decays, we find that the determinations of both the vector form factor $f_+^K(q^2)$ and scalar form factor $f_0^K(q^2)$ for semileptonic $D\rightarrow K$ decays from these measurements are feasible. By taking the parameterization of the one order series expansion of the $f_+^K(q^2)$ and $f_0^K(q^2)$, $f_+^K(0)|V_{cs}|$ is determined to be $0.7182\pm0.0029$, and the shape parameters of $f_+^K(q^2)$ and $f_0^K(q^2)$ are $r_{+1}=-2.16\pm0.007$ and $r_{01}=0.89\pm3.27$, respectively. Combining with the average $f_+^K(0)$ of $N_f=2+1$ and $N_f=2+1+1$ lattice calculaltion, the $|V_{cs}|$ is extracted to be $0.964\pm0.004\pm0.019$ where the first error is experimental and the second theoretical. Alternatively, the $f_+^K(0)$ is extracted to be $0.7377\pm0.003\pm0.000$ by taking the $|V_{cs}|$ as the value from the global fit with the unitarity constraint of the CKM matrix. Moreover, using the obtained form factors by $N_f=2+1+1$ lattice QCD, we re-analyze these measurements in the context of new physics. Constraints on scalar leptoquarks are obtained for different final states of semileptonic $D \rightarrow K$ decays

Neutrino mu-tau reflection symmetry and its breaking in the minimal seesaw

In this paper, we attempt to implement the neutrino $\mu$-$\tau$ reflection symmetry (which predicts $\theta^{}_{23} = \pi/4$ and $\delta = \pm \pi/2$ as well as trivial Majorana phases) in the minimal seesaw (which enables us to fix the neutrino masses). For some direct (the preliminary experimental hints towards $\theta^{}_{23} \neq \pi/4$ and $\delta \neq - \pi/2$) and indirect (inclusion of the renormalization group equation effect and implementation of the leptogenesis mechanism) reasons, we particularly study the breakings of this symmetry and their phenomenological consequences.Comment: 20 pages, 7 figures, accepted for publication in JHE