城市生命线系统危机分析与评估

城市生命线系统出现问题,可能造成整个城市瘫痪,易引发社会危机,是城市公共安全的重要领域.根据城市生命线系统承载的物质及能量的特性、脆弱性和可能引发的连锁效应,分析和评估城市生命线系统危机特征和种类,得到具体的危机源;分析和总结我国城市生命线系统危机管理现状和控制效果,发现其存在的主要问题,进而提出改进我国城市生命线系统危机管理的对策措施建议.     

Financial analyst coverage for U.S. firms facing foreign competition: Evidence from trade liberalization

This study examines financial analyst coverage for U.S. firms following an increase in foreign product market competition. To capture exogenous shocks to domestic firms' competitive environments, we exploit a quasi‐natural experiment from large import tariff reductions over the 1984 to 2005 period in the manufacturing sector. Using data for the years before and after large tariff reductions, our difference‐in‐differences analysis shows evidence of a significant decrease in analyst coverage for incumbent U.S. firms when they face greater entry threat from foreign competitors. We also find that analysts with less firm‐specific experience and less accurate prior‐period forecasts are more likely to stop following the domestic firm when foreign competition intensifies. Overall, the findings suggest that foreign product market competition from global trade liberalization is an important determinant of financial analysts' coverage decisions.     

Informal Property Rights as Relational and Functional: Unravelling the Relational Contract in China's Informal Housing Market

In the face of state-led land grabs, enterprising Chinese peasants have started a revolution in the ambiguous and insecure rural tenure system by developing an extralegal property system known as the small property right (SPR). Using the SPR, peasants are able to capitalize on their property through the sale of houses built on collectively owned land. Little is known, however, about the specific process behind the development of the SPR by the peasants, or how this extralegal property system functions in terms of securing the use and transfer of property without the backing of law. This article aims to clarify the situation through the lenses of the Endogenous Nature of Institutions and Relational Contract Theory, aiming to understand the socially constructed, endogenous and relational nature of the property rights that make SPR functional. Based on an ethnographic investigation of Beijing's largest SPR housing settlement, we show how enterprising peasants develop long-term relational contracts with urban households for the provision of housing services, secured on the basis of the common interests and symbiosis of the two parties and a reputation system that serves to deter defaults. The discretionary treatment of SPR housing by local states serves as a further motivation for the village and the informal homeowners to preserve a stable property arrangement, with such a specific institutional setting being an exemplar of China's pragmatic state entrepreneurialism.     

Input use under cost-of-production crop insurance: Theory and evidence

There have been a number of previous studies that examined the effects of yield- or revenue-based crop insurance products on input use of farmers. However, no study has specifically investigated the input use impacts of a cost-of-production (COP) crop insurance policy, even though this type of crop insurance is the predominant one used in several other countries outside of the United States (such as the Philippines and China). This article aims to theoretically and empirically examine the effect of a COP crop insurance product on farmers’ chemical input use. Our theoretical model suggests that the effect of COP insurance on input use can either be positive or negative, with the resulting impact depending on the strengths of (a) the traditional moral hazard effect of insurance (i.e., an input use decreasing effect); versus (b) the marginal incentives to apply more inputs due to input levels being the main determinant for expected indemnity amounts in this type of insurance (i.e., an input use increasing effect). A survey data set from corn farmers in the Philippines is then used to empirically illustrate how a particular COP insurance product influences input use in a real-life context. In this case, we find that COP insurance increases the use of chemical inputs (e.g., fertilizers and total chemical expenditure), implying that the positive marginal incentive to apply more inputs dominates the negative moral hazard effect.     

刺芪参胶囊的制备工艺研究

目的:探索刺芪参胶囊的制备工艺。方法:采用正交实验,以总皂苷质量为指标,优化提取工艺;采用单因素实验优化制剂工艺。结果:在最佳提取工艺条件下,刺芪参胶囊提取物中的总皂苷含量为12.19 mg·g-1;以糊精作为填充剂、硬脂酸镁为助流剂、95%乙醇为黏合剂制备胶囊剂。结论:刺芪参胶囊的制备工艺稳定可行。     

吐温80在油脂类调味品中微生物检测的研究分析

通过对牛肉酱、红油2种即食油脂类调味品进行微生物检测,将不同比例的吐温80添加到样品前处理的稀释液中,采用浓度为107 CFU·mL-1的标准菌悬液,用常规细菌培养法检测结果。结果表明:选用比例为5%的吐温80对牛肉酱、红油的微生物指标进行检测,检测结果均在107 CFU·mL-1,与空白对照的检测结果在同一数量级上。与常规的稀释液相比,吐温80可使样品均匀分散在稀释液中,且不影响微生物的检测结果,可适用于高油脂类样品的日常微生物检测。     

Does Investor Sentiment Affect the Value Relevance of Accounting Information?

We investigate whether investor sentiment affects the relationships between accounting variables and contemporaneous stock returns. Using price-relevant accounting variables identified by Chen and Zhang (2007) and the investor sentiment index constructed by Baker and Wurgler (2006), we find that the value relevance of accounting variables is collectively lower in high sentiment periods than in low sentiment periods. More importantly, earnings yield appears to be more related to contemporaneous stock returns in high sentiment periods, while other accounting variables are more related to stock returns in low sentiment periods. The effect of investor sentiment on the value relevance of accounting information is stronger for firms that are more difficult to value and to arbitrage.     

从经适房政策解析政府在社会保障均等化中的角色定位

文章从非受益群体对于经适政策公平性的质疑角度入手,挖掘出导致社会普遍不公平感的更深层次原因,着重体现公民的情感接受,并借助经济学理论,尝试重新定义社会保障公平性原则,以社会保障均等化概念代替社会公平概念来解释经适房政策,从而推进政府角色的进一步转变。     

透过亚当斯领略黑白摄影的魅力

在漫长的黑白摄影发展的进程中,摄影大师安塞尔·亚当斯做出了卓越的贡献,尤其是"f64小组"和完善的区域曝光系统成为摄影史上的里程碑。黑、白、灰黑白摄影演绎着影调与影像的经典,即使在现代彩色摄影高度发展的今天,黑白摄影并没有失去它往日的光彩,也不会被彩色摄影所更替,它将以独特的魅力,以单纯、洗练、视觉冲击力强等审美优势继续发展,创造更多视觉财富。     

印度资本项目可兑换的经验与启示

印度自1991年以来积极推进资本项目可兑换。经过20年的实践,印度迅速融入国际金融市场,有效抵御了金融危机的冲击,资本项目可兑换取得明显成效,主要特点：一是采取渐进、审慎的方式推进资本项目可兑换;二是坚持控制的主动性和必要时恢复管制的灵活性;三是深化金融改革,为资本项目可兑换创造良好的外部条件;四是注重通过宏观调控手段,优化资本流动结构,解决资本流动中产生的问题;五是加强短期资本流动管制,防止短期资本流动对经济的冲击;六是加强房地产资本管制,防止国际投机资本引发房地产风险。