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The yield curve of the Treasury bonds has important economic implications. Its shape can reflect the expectation of the economy, and the corresponding trading strategy can be formulated by ...

This paper analyses risk-integration and the degree of dependence between the Values-at-Risk (VaRs) estimates for the two major pharmaceutical stock markets in the world: USA and China. To do this, we study the dependence and fractional cointegration properties among risks. Using daily returns for an eleven-year period, we estimated the VaRs obtained for pharmaceutical market portfolios in China (Shanghai) and the USA (NYSE) using the market model and considering both long and short trading positions. We conclude that the Shanghai pharmaceutical market is riskier than NYSE, although is predictable and losses in both markets exhibit tail dependence between VaR estimates. Particularly, there is lower tail VaR dependence for long position and upper tail dependence for short positions, both being small and fairly constant. On the other hand, we have not found fractional cointegration between risks, suggesting that China’s pharmaceutical sector is not integrated into the global pharmaceutical market.

The physiological and ecological responses of Ulmus elongata to different concentrations of nano-anatase TiO2 solutions were investigated in this study and we found that with foliar application of 0.1% (T1), 0.2% (T2) and 0.4% (T3) nano-anatase TiO2 solution the net photosynthetic rate of U. elongata seedlings were lower, comparing with the control (CK) (no spraying). TiO2 solution had no effect on the carbon isotope values (δ(13)C), indicating the lower photosynthetic capacity was not caused by stomatal limitation. The nitrogen isotope values (δ(15)N) decreased, but the foliar metal elements, such as Mg, K and Mn contents were not affected by nano-anatase TiO2 which promoted the Cu uptake. Fourier transform infrared spectroscopy showed that the nano-anatase TiO2 enhanced the absorbance of U. elongata leaves, especially for 1064, 1638, 2926 and 3386 cm(-1) bands, indicating the synthesis of carbohydrate and lipid compounds was a kind of mechanism under the toxic effects of nanonanoparticles.

A rapid electrostatic assembly method has been developed for deposition of highly dispersed TiO2 nanoparticles on the surface of carbon spheres. Surface charges on carbon spheres are found to facilitate the spontaneous deposition of the TiO2 nanoparticles, in which no additional chemicals are required in this assembling process. In the formed C/TiO2 hybrid structure, carbon microspheres not only reduce the agglomeration of TiO2 nanoparticles, but also allow easy separation from the reaction medium for reuse. Remarkably, the as-prepared C/TiO2 hybrid microspheres exhibit a superior adsorption capacity for Cr(VI), which is 3.6 times greater than that of commercial Degussa P25 TiO2 nanoparticles. The effect of pH value in solution on the adsorption capacity of the products has also been systematically investigated.

The physiological and ecological responses of Ulmus elongata to different concentrations of nano-anatase TiO2 solutions were investigated in this study and we found that with foliar application of 0.1% (T1), 0.2% (T2) and 0.4% (T3) nano-anatase TiO2 solution the net photosynthetic rate of U. elongata seedlings were lower, comparing with the control (CK) (no spraying). TiO2 solution had no effect on the carbon isotope values (δ(13)C), indicating the lower photosynthetic capacity was not caused by stomatal limitation. The nitrogen isotope values (δ(15)N) decreased, but the foliar metal elements, such as Mg, K and Mn contents were not affected by nano-anatase TiO2 which promoted the Cu uptake. Fourier transform infrared spectroscopy showed that the nano-anatase TiO2 enhanced the absorbance of U. elongata leaves, especially for 1064, 1638, 2926 and 3386 cm(-1) bands, indicating the synthesis of carbohydrate and lipid compounds was a kind of mechanism under the toxic effects of nanonanoparticles.

TiO(2)-Ag hybrid hollow spheres (about 700 nm in diameter) with a highly uniform morphology and good structural stability were facilely prepared via a one-pot hydrothermal method, using carbon spheres as templates followed by an annealing treatment. Through this route, the as-prepared hybrid hollow spheres preserved the uniformity of the initial carbon sphere templates and the loading amount of the Ag nanocrystals can be conveniently varied or controlled by the concentration of the Ag precursor. The investigation of the photocatalytic ability demonstrated that the as-prepared TiO(2)-Ag hybrid hollow spheres possess excellent photocatalytic activity, superior to commercial TiO(2) nanoparticles (Degussa P25), for the degradation of rhodamine B (RhB) and methyl orange (MO) dyes under visible-light illumination. Furthermore, the ˙OH radicals formed during photocatalysis with different Ag content hybrids were revealed by means of a terephthalic acid fluorescence probe method, which uncovers that the Ag content in the TiO(2)-Ag hybrids was crucial to obtain an optimal synergistic effect between the Ag and TiO(2) for the degradation of organic pollutants. Accordingly, the optimum matching for the best photocatalytic activity was investigated thoroughly and a reasonable mechanism was also proposed.

We demonstrate a facile and novel chemical precipitation strategy for the accurate coating of TiO2nanoparticles on the surface of carbon nanotubes (CNTs) to form CNT/TiO2nanohybrids, which only requires titanium sulfate and CNTs as starting materials and reacts in the alkaline solution at 60°C for 6 h. Using this process, the as-prepared hybrid structures preserved the good dispersity and uniformity of initial CNTs. Furthermore, the CNT/TiO2nanohybrids show a broad blue luminescence at 469 nm and exhibit significantly enhanced photocatalytic activity for the degradation of rhodamine B (RhB) under visible-light irradiation, which is about 1.5 times greater than that of commercial Degussa P25 TiO2nanoparticles. It is believed that this facile chemical precipitation strategy is scalable and its application can be extended to synthesize other CNT/oxide nanohybrids for various applications.

In order to maximize the profits from oil recovery, an optimal control approach for reservoir production working systems using gradient-based method is considered in the paper. It regards reservoir as a large-scale complex dynamic system. On the basis of flow dynamics, reservoir numerical simulation and optimal control theories, the optimization mathematical model of production working system is established. The optimal objective is to maximize net present value or accumulative oil production. Using the algorithm presented to solve the optimal control problem, gradients of real-time control parameters are obtained. And then optimal control settings of each control step can be determined. Finally, a simulation example is employed to verify the validity of the proposed control algorithm.

We demonstrate a new strategy for preparation of ZnO/ZnS core–shell nanorods via microwave-assisted in situ surface sulfidation of ZnO nanorods. This is a facile and rapid process, requiring only a low level of microwave irradiation (400 W), through which a conformal ZnS nanoparticle layer is deposited onto the ZnO nanorods, while retaining the uniformity of the original ZnO nanorods in the as-prepared ZnO/ZnS hybrid structures with excellent fidelity. Furthermore, the thickness and nanoparticle size of the ZnS shell can be conveniently varied or controlled by the concentration of the organo-sulfur source thioacetamide (TAA). The as-prepared products exhibit narrowed band gap and strong orange luminescence at 621 nm, due to the interstitial oxygen ion defect present in hydrothermally grown ZnO. However, the PL intensity gradually decreases with the increase of the thickness of ZnS shell, indicating charge transfer between the two components of the ZnO/ZnS hybrids. Further investigation has revealed that the hybrid nanostructures possess significantly higher visible light photocatalytic activity which is twice that of the original ZnO nanorods. The mechanisms of the optimal ZnS shell thickness to reach the maximum photocatalytic activity in the ZnO/ZnS core-shell hybrid are proposed and discussed. It is believed that this facile, rapid microwave-assisted strategy is scalable and its application can be extended synthesize other oxide/sulfide (MOx/MSy) core-shell nanostructures for different applications.