Economic Reform, Education Expansion, and Earnings Inequality for Urban Males in China, 1988-2007

In the past 20 years the average real earnings of Chinese urban male workers have increased by 350 per cent. Accompanying this unprecedented growth is a considerable increase in earnings inequality. Between 1988 and 2007 the variance of log earnings increased from 0.27 to 0.48, a 78 per cent increase. Using a unique set of repeated cross-sectional data this paper examines the causes of this increase in earnings inequality. We find that the major changes occurred in the 1990s when the labour market moved from a centrally planned system to a market oriented system. The decomposition exercise conducted in the paper identifies the factor that drives the significant increase in the earnings variance in the 1990s to be an increase in the within-education-experience cell residual variances. Such an increase may be explained mainly by the increase in the price of unobserved skills. When an economy shifts from an administratively determined wage system to a market-oriented one, rewards to both observed and unobserved skills increase. The turn of the century saw a slowing down of the reward to both the observed and unobserved skills, due largely to the college expansion program that occurred at the end of the 1990s.Earnings inequality, China

Economic Reform, Education Expansion, and Earnings Inequality for Urban Males in China, 1988-2007

In the past 20 years the average real earnings of Chinese urban male workers have increased by 350 per cent. Accompanying this unprecedented growth is a considerable increase in earnings inequality. Between 1988 and 2007 the variance of log earnings increased from 0.27 to 0.48, a 78 per cent increase. Using a unique set of repeated cross-sectional data this paper examines the causes of this increase in earnings inequality. We find that the major changes occurred in the 1990s when the labour market moved from a centrally planned system to a market oriented system. The decomposition exercise conducted in the paper identifies the factor that drives the significant increase in the earnings variance in the 1990s to be an increase in the within-education-experience cell residual variances. Such an increase may be explained mainly by the increase in the price of unobserved skills. When an economy shifts from an administratively determined wage system to a market-oriented one, rewards to both observed and unobserved skills increase. The turn of the century saw a slowing down of the reward to both the observed and unobserved skills, due largely to the college expansion program that occurred at the end of the 1990s.earnings inequality, China

Quantum Spin Liquid with Even Ising Gauge Field Structure on Kagome Lattice

Employing large-scale quantum Monte Carlo simulations, we study the extended $XXZ$ model on the kagome lattice. A $\mathbb Z_2$ quantum spin liquid phase with effective even Ising gauge field structure emerges from the delicate balance among three symmetry-breaking phases including stripe solid, staggered solid and ferromagnet. This $\mathbb{Z}_2$ spin liquid is stabilized by an extended interaction related to the Rokhsar-Kivelson potential in the quantum dimer model limit. The phase transitions from the staggered solid to a spin liquid or ferromagnet are found to be first order and so is the transition between the stripe solid and ferromagnet. However, the transition between a spin liquid and ferromagnet is found to be continuous and belongs to the 3D $XY^*$ universality class associated with the condensation of spinons. The transition between a spin liquid and stripe solid appears to be continuous and associated with the condensation of visons.Comment: 7 pages, 8 figure

Social Networks and Mental Health Problems: Evidence from Rural-to-Urban Migrants in China

Over the past two decades, more than 160 million rural residents have migrated to cities in China. They are usually separated from their rural families and work in an unfamiliar, and sometimes hostile, city environment. This paper investigates to what extent city social networks alleviate mental health problems among these migrants. Using the longitudinal migrant survey from the Rural-to-Urban Migration in China (RUMiC) project, we find that larger social networks are significantly correlated with fewer mental health problems in both OLS and fixed effect estimates. To mitigate the endogeneity issue, we use past rainfall in the home county and the distance between home village and the closest transportation centre as the instrument variables for city social networks. The instrument variable estimates and fixed effect instrumental variable estimates suggest that an additional person in the city social networks of migrants reduces GHQ 12 by 0.12 to 0.16 Likert points. The results are robust for migrants who are less educated, who work long hours and who do not have access to social insurances in the city

Deciphering Charging Status, Absolute Quantum Efficiency, and Absorption Cross Section of MultiCarrier States in Single Colloidal Quantum Dot

Upon photo- or electrical-excitation, colloidal quantum dots (QDs) are often found in multi-carrier states due to multi-photon absorption and photo-charging of the QDs. While many of these multi-carrier states are observed in single-dot spectroscopy, their properties are not well studied due to random charging/discharging, emission intensity intermittency, and uncontrolled surface defects of single QD. Here we report in-situ deciphering the charging status, and precisely assessing the absorption cross section, and determining the absolute emission quantum yield of mono-exciton and biexciton states for neutral, positively-charged, and negatively-charged single core/shell CdSe/CdS QD. We uncover very different photon statistics of the three charge states in single QD and unambiguously identify their charge sign together with the information of their photoluminescence decay dynamics. We then show their distinct photoluminescence saturation behaviors and evaluated the absolute values of absorption cross sections and quantum efficiencies of monoexcitons and biexcitons. We demonstrate that addition of an extra hole or electron in a QD changes not only its emission properties but also varies its absorption cross section

Superconductivity in pure and electron doped MgB2: Transport properties and pressure effects

The normal state and superconducting properties of MgB2 and Mg1-xAlxB2 are discussed based on structural, transport, and high pressure experiments. The positive Seebeck coefficient and its linear temperature dependence for Tc<T<160 K provide evidence that the low-temperature transport in MgB2 is due to hole-like metallic carriers. Structural and transport data show the important role of defects as indicated by the correlation of Tc, the residual resistance ratio, and the microstrain extracted from x-ray spectra. The decrease of Tc with hydrostatic pressure is well explained by the strong-coupling BCS theory. The large scatter of the pressure coefficients of Tc for different MgB2 samples, however, cannot be explained within this theory. We speculate that pressure may increase the defect density, particularly in samples with large initial defect concentration.Comment: Presented at NATO Advanced Research Workshop "New Trends in Superconductivity", Yalta (Ukraine) 16-20 September, 200