The effect of early resolution of uncertainty on the valuation of assets: A dichotomy into market and non-market information

We reconsider how the temporal resolution of uncertainty about the future payoffs from capital assets affects the initial valuation of these assets. Our results regarding valuation indicate that, in an intertemporal CAPM framework, the early resolution of market uncertainty leads to an increase in the value of the market portfolio. The values of individual assets change in direct proportion to their betas. We reconcile the differing conclusions of Ross (1989) and Epstein and Turnbull (1980) regarding the early resolution of what they term idiosyncratic and asset specific information respectively.     

某低流行地区1995～2012年艾滋病疫情流行特征分析

目的了解1995～2012年某低流行地区艾滋病疫情流行特征，为今后当地预防控制艾滋病提供科学依据。方法根据中国疾病预防控制信息系统中的艾滋病综合防治信息的上报数据，对1995～2012年报告的艾滋病病毒感染者/艾滋病病人( HIV/AIDS)的资料进行流行病学分析。结果1995～2012年累计报告HIV/AIDS104例，其中男性83例，女性21例，男性明显高于女性；职业分布以农民和工人为主，占78.7%；高发年龄为20～49年龄组，占86.5%。感染者文化程度以初中及以下为主，占62.5%；传播途径以性传播为主，占80.9%；自2007年以来，报告病例数逐渐增多。结论该地区疫情仍处于低流行地区，2007年以来，感染人数逐年增多，感染人数主要集中在文化程度低的男性青壮年农民（农民工），性途径是最主要的传播途径，男男性行为传播上升明显。     

Demand uncertainty,competition, and ‘non-binding’ price controls

In our paper, we will present a general model that demonstrate that a price floor or a price ceiling, although not effective at the existing market price, nevertheless alters the competitive equilibrium and leads to erroneous policy conclusions.     

Testing for negative expected market return premia

This paper tests the hypothesis that the expected return premium on the market portfolio is always non-negative. A violation of this lower bound restriction provides evidence against a broad class of risk-based equilibrium models in favor of bubble behavior. Our tests utilize information variables, identified in prior literature, that predict time variation in market return premia. We employ out-of-sample forecasts and bootstraps generated with parameters that are consistent with non-negativity but closest to the estimated parameters. We find statistically reliable evidence against non-negativity for the excess return on the value-weighted market index. The most negative out-of-sample prediction was −2.01% in September 1973.     

Market liberalization within a country

China's B-share market, which used to be restricted to foreign investors, was partially opened up in February 2001 to Chinese local investors. We take this as a controlled experiment in cross-border trading on a small scale. We find mild but positive effects on the B-share market, with higher volumes, lower levels of volatility, lower bid–ask spreads and more liquidity after liberalization. Between A- and B-shares, price disparities narrowed; the correlation and the co-integration relationships became stronger; and the flow of information became more balanced. More new individual investors entered into the B-share market without crowding out existing institutional investors. Even though the liberalization measure is partial and one-way, it has helped to improve the quality of the B-share market, and our results lend no support to the popular claim that liberalization does nothing but help the existing foreign shareholders to cash out.     

Survey Accuracy as a Function of Usage Rate

Using a large-scale AT&T database, we decompose usage levels into frequency and duration, and then investigate how they affect survey response accuracy. Results show that more accurate surveys are obtained from those in the high frequency group (possibly because of the increased use of the more accurate rate-based method of recall and higher degrees of regularity), and from those in the longer duration group (possibly because of increased involvement). We therefore suggest that the survey method is less suited for light users because of higher error, and that alternative methods such as diaries might be more appropriate. We also found similarly consistent results with respect to self-perception of usage rate and the accuracy of survey recall.     

粉煤灰制备聚硅酸盐絮凝剂的研究进展

介绍了粉煤灰的现状和主要化学成分及性质,综述了高效提取粉煤灰中硅、铝和铁的方法,以及利用提取物质制备聚硅酸盐絮凝剂的方法、条件和水处理效果;重点分析了粉煤灰的物化改性的方法、原理和效果,总结了粉煤灰制备絮凝剂的工艺和方法,对如何更高效提取粉煤灰中有用物质和制备更优越絮凝性能的絮凝剂提出了建议.     

PLC控制系统的抗干扰措施

介绍PLC控制系统软硬件设计、系统安装时的抗干扰措施和方法.