Longitudinal studies are often conducted to explore the cohort and age effects in many scientific areas. The within cluster correlation structure plays a very important role in longitudinal data analysis. This is because not only can an estimator be improved by incorporating the within cluster...

Multiparameter likelihood models (MLMs) with multiple covariates have a wide range of applications: however. they encounter the "curse of dimensionality" problem when the dimension of the covariates is large. We develop a generalized multiparameter likelihood model that copes with multiple...

A first-principles study has been performed to evaluate the electronic and optical properties of wurtzite Zn<Subscript>1-x</Subscript>Mg<Subscript>x</Subscript>O. Substitutional doping is considered with Mg concentrations of x=0, 0.0625, 0.125, 0.1875 and 0.25, respectively. Mg incorporation can induce band gap widening due to the decrease...</subscript></subscript>

The spin-states of cobalt based perovskite compounds depend sensitively on the valence state and local crystal environment of Co ions and the rich physical properties arise from strong coupling among charge, spin, and orbital degrees of freedom. While extensive studies have been carried out in...

We study the propagation of electromagnetic wave in piezoelectric period-doubling superlattices with using the generalized 4 × 4 transfer matrix method, and the dynamics of electromagnetic wave and acoustic wave is treated on equal footing. The band-gap structure trifurcates, which is...

Purpose: The purpose of this paper is to estimate the impact of China's outward foreign direct investment (OFDI) conducted by exporting firms on their productivity. Design/methodology/approach: This study uses two Chinese firm-level datasets. To reduce the bias when merging the two datasets,...