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Continuous disposal of endocrine-disrupting compounds (EDCs) into the environment can lead to serious human health problems and can affect plants and aquatic organisms. The determination of EDCs in water has become an increasingly important activity due to our increased knowledge about their toxicities, even at low concentration. The EDCs in water samples from the reclaimed water plant of Tianjin, northern China, were identified by gas chromatography (GC)-mass spectrometry (MS). Important and contrasting EDCs including estrone (E1), 17beta-estradiol (E2), 17alpha-ethynylestradiol (EE2), 4-tert-octylphenol (OP), 4-nonylphenol (NP), bisphenol A (BPA), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl)phthalate (DEHP) were selected as the target compounds. Concentrations of steroid hormones, alkylphenolic compounds and phthalates ranged from below the limit of detection (LOD) to 8.1 ng L(-1), from

We develop and estimate a dynamic model of investment to investigate the impact of international oil price uncertainty on corporate investment expenditures in China's emerging and transition economy. We further examine whether state ownership affects the relationship between oil price uncertainty and corporate investment. Consistent with the model's prediction, the main finding is that oil price uncertainty exerts a negative impact on corporate investment expenditures. In addition, compared with state-owned listed companies, the negative influence of oil price uncertainty on corporate investment is more significant for non-state-owned listed companies. Our further analysis, using the market-oriented reform of refined oil pricing in 2008 as a quasi-natural event, shows the variation between the low-degree marketization period and the high-degree one in terms of the relationship between

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Together with regular retail channel, a firm can distribute products directly through Internet (referred to as an "e-tail" distribution channel). The competitive edge of the retail channel lies in more value-added services, some of which are unavailable through the e-tail channel. We consider a model mixed with retailing and e-tailing distribution channels where the service level and price decision are made, respectively, ex ante and ex post demand realizations. From the firm's perspective of managing the two channels, we acquire the optimal decisions and characterize the effects of the demand uncertainty on the firm's optimal retail service and expected profit. Applying stochastic comparison method, we show the firm's retail service and profit both increase in the demand mean, and the firm profits from the increase of the convex order of the demand by decreasing his service level. Further, if the coefficient of the demand increases, we characterize that the firm benefits from it. Finally, several numerical studies are presented to gain insights.

As the clinical application grows, there is a rapid technical development of 3-D ultrasound imaging. Compared with 2-D ultrasound imaging, 3-D ultrasound imaging can provide improved qualitative and quantitative information for various clinical applications. In this paper, we proposed a novel tracking method for a freehand 3-D ultrasound imaging system with improved portability, reduced degree of freedom, and cost. We designed a sliding track with a linear position sensor attached, and it transmitted positional data via a wireless communication module based on Bluetooth, resulting in a wireless spatial tracking modality. A traditional 2-D ultrasound probe fixed to the position sensor on the sliding track was used to obtain real-time B-scans, and the positions of the B-scans were simultaneously acquired when moving the probe along the track in a freehand manner. In the experiments, the proposed method was applied to ultrasound phantoms and real human tissues. The results demonstrated that the new system outperformed a previously developed freehand system based on a traditional six-degree-of-freedom spatial sensor in phantom and in vivo studies, indicating its merit in clinical applications for human tissues and organs.

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