This paper explores whether educational attainment has a cognitive reserve capacity in elder life. Using pilot data from the China Health and Retirement Longitudinal Study (CHARLS), we examined the impact of education on cognitive abilities at old ages. OLS results showed that respondents who completed primary school obtained 18.2 percent higher scores on cognitive tests than those who did not. We then constructed an instrumental variable (IV) by leveraging China's Great Famine of 1959–1961 as a natural experiment to estimate the causal effect of education on cognition. Two-stage least squares (2SLS) results provided sound evidence that completing primary school significantly increases cognition scores, especially in episode memory, by almost 20 percent on average. Moreover, Regression Discontinuity (RD) analysis provides further evidence for the causal interpretation, and shows that the effects are different for the different measures of cognition we explored. Our results also show that the Great Famine can result in long-term health consequences through the pathway of losing educational opportunities other than through the pathway of nutrition deprivation.
Efficient all-optical molecule-plasmon modulation is experimentally demonstrated by employing a compact T-shape single slit on a metal film coated with an azopolymer film, in which the azobenzene molecules can be reoriented by a pump beam. In the T-shape single slit, the transmission spectra exhibit periodic behaviors and are quite sensitive to variations of the refractive index of the azopolymer in the groove. Under a pump beam, the azobenzene molecules are reoriented, so the SPPs in the groove feel a refractive index quite different from that of the originally isotropic azopolymer with randomly orientations. This leads to a high modulation depth of about 53 % (3.3 dB) and a phase variation of >pi experimentally.
We present for the first time an efficient iterative method to directly solve the four-component Dirac-Kohn-Sham (DKS) density functional theory. Due to the existence of the negative energy continuum in the DKS operator, the existing iterative techniques for solving the Kohn-Sham systems cannot be efficiently applied to solve the DKS systems. The key component of our method is a novel filtering step (F) which acts as a preconditioner in the framework of the locally optimal block preconditioned conjugate gradient (LOBPCG) method. The resulting method, dubbed the LOBPCG-F method, is able to compute the desired eigenvalues and eigenvectors in the positive energy band without computing any state in the negative energy band. The LOBPCG-F method introduces mild extra cost compared to the standard LOBPCG method and can be easily implemented. We demonstrate our method in the pseudopotential framework with a planewave basis set which naturally satisfies the kinetic balance prescription. Numerical results for Pt$_{2}$, Au$_{2}$, TlF, and Bi$_{2}$Se$_{3}$ indicate that the LOBPCG-F method is a robust and efficient method for investigating the relativistic effect in systems containing heavy elements.
A bacterium capable of phosphorus removal was isolated. Through morphology observation and 16S rRNA gene sequence analysis, the isolate was identified as Salinivibrio sp. (named HG-1). Salinity tolerance and phosphorus removal efficiency under different salinity conditions of the strain were further investigated. The results showed that HG-1 grew well with the salt content varying from 1% to 13% and achieved the highest phosphorus removal efficiency under salt content of 3%. Furthermore, the single-factor and orthogonal experiment results indicated that the optimal phosphorus removal performance was obtained under the conditions with an initial pH of 6.5-7.0, C/N ratio of 9, temperature of 30°C and inoculation ratio of 10%. Under such a condition, the phosphorus removal efficiency could reach 100% in 24 hours. The strain HG-1 can independently complete phosphorus removal process, and thus could provide a novel and promising alternative for biological phosphorus removal under high salinity conditions.筛选出一株能够高效除磷的耐盐菌株HG-1。通过个体形态、菌落特征的观察和16S rRNA基因的序列分析, 初步鉴定为盐弧菌属(Salinivibrio sp.)。对菌株HG-1的耐盐性能及其在不同盐度下对磷酸盐的去除效果进行考察, 结果表明菌株对盐度的耐受范围为1%~13%, 最适盐度为3%。进一步的单因素和正交实验表明, 4个环境因素对菌株HG-1磷酸盐去除率影响的强弱为: pH>碳氮比>温度>接种量, 最优的除磷条件为pH 6.5~7.0, 温度30℃, 接种量10%, 碳氮比9, 在该条件下菌株在24小时内对磷酸盐的去除率可达100%。 将该菌株应用于高盐废水的处理, 可实现磷酸盐的有效去除, 具有良好的实际应用价值, 为高盐条件下生物除磷难题的解决提供了一条新的途径。
A micromechanics-based elastoplastic constitutive model for porous materials is proposed. With an assumption of modified three-dimensional Ramberg-Osgood equation for the compressible matrix material, the variational principle based on a linear comparison composite is applied to study the effective mechanical properties of the porous materials. Analytical expressions of elastoplastic constitutive relations are derived by means of micromechanics principles and homogenization procedures. It is demonstrated that the derived expressions do not involve any additional material constants to be fitted with experimental data. The model can be useful in the prediction of mechanical properties of elastoplastic porous solids.