The mean-variance investment problem in a constrained financial market

This paper extends the mean-variance analysis and the two-fund separation theorem to a market with some constraints, such as, the incompleteness, prohibition of short-selling, and partial information, with stochastic interest rate, and with stochastic volatility for risky assets. By maximizing a quadratic utility of terminal wealth, we show that the efficient frontier for the problem is a straight line in the mean-standard-deviation diagram. The quadratic utility function exhibits mean-variance efficiency. Our results apply to portfolios of claims in a single period, multiperiod, and continuous time.     

Trade liberalisation,market competition and wage inequality in China's manufacturing sector

Economic reforms of the late 1980s have contributed to rapid economic growth in China. While the overall standard of living has improved, economic growth has also resulted in an increase in income inequality. Rising income inequality can increase social tensions that can impede further economic growth. By making use of firm level panel data, this paper focuses on the impact of increased market competition and trade liberalisation on skilled–unskilled wage inequality in China's manufacturing sector. A theoretical model is used to argue that trade liberalisation and market competition can affect skilled–unskilled wage inequality. Based on this result, an econometric model is specified. The empirical analysis presented in this paper shows that increased trade liberalisation has contributed to an increase in skilled–unskilled wage inequality in China's manufacturing sector. However, increase in market competition has the opposite effect.     

以人为本理念在妇产科护理管理的应用效果分析

目的分析以人为本的护理理念在妇产科护理管理中的具体应用效果。方法随机选取了2012年1月至12月在我院接受治疗的妇产科患者202例作为研究对象,随机分为两组,其中对照组患者采取常规护理方法,而实验组患者则采取的是以人为本的护理措施,采取科学的评价方法,对两组患者的护理效果进行比较分析。结果实验组患者在经过护理干预后,患者疾病的不确定感下降,患者自身的满意度提升,与对照组患者比较差异具有显著的统计学意义,P＜0.05。结论采取以人为本的护理理念在妇产科的护理中有比较好的应用价值,能够收到比较好的护理效果,所以值得在临床上进行应用推广。     

宁南旱作农区生态经济农业发展思路研究

宁南旱作农区是我国经济落后的地区．生态环境十分严酷，农民生活十分贫穷。按照西部大开发的战略要求，保护生态，实现社会经济与生态恢复同步发展已成为该地区当前和以后相当长一段时期的主要任务。面对中国小康社会建设目标和农业现代化要求，发展草畜一体化生态经济农业将是该地区经济发展的战略选择，以草畜产业为基础的生态经济农业必将成为干旱半干旱地区可持续发展的主要途径。     

Agriculture and aggregate productivity: A quantitative cross-country analysis

A decomposition of aggregate labor productivity based on internationally comparable data reveals that a high share of employment and low labor productivity in agriculture are mainly responsible for low aggregate productivity in poor countries. Using a two-sector general-equilibrium model, we show that differences in economy-wide productivity, barriers to modern intermediate inputs in agriculture, and barriers in the labor market generate large cross-country differences in the share of employment and labor productivity in agriculture. The model implies a factor difference of 10.8 in aggregate labor productivity between the richest and the poorest 5% of the countries in the world, leaving the unexplained factor at 3.2. Overall, this two-sector framework performs much better than a single-sector growth model in explaining observed differences in international productivity.     

FOREIGN ENTRY INTO U.S. SERVICE INDUSTRY BY TAKEOVERS AND THE CREATION OF NEW FIRMS

We study the relation between foreign entry in U.S. service sector industries and the revealed comparative advantage of the investing country using U.S. Bureau of Economic Analysis firm‐level data on all foreign takeovers and new foreign‐owned firms from 1998 to 2008. We find foreign acquisitions in the service sector are in industries of U.S. comparative advantage while new foreign firms are in industries of investing country's comparative advantage. This suggests that foreign acquisitions in the service sector are not directly related to foreign investors' competitiveness in the industry of investment. In contrast foreign investors in new service sector firms come from countries with a competitive edge in the industries of investment. We also find that foreign investors of new service sector firms are from Organization for Economic Co‐operation and Development (OECD) countries with a comparative disadvantage in royalties and trademarks. (JEL F21, F23, G34)     

安徽省亳州市小麦产业现状与发展策略研究

目的 亳州市位于黄淮麦区,是安徽省小麦种植面积第二大地市,亳州小麦产业化发展对安徽省至关重要,总结亳州小麦产业发展现状,分析其存在的主要问题,为亳州小麦产业化发展提供建议。方法 文章通过对亳州小麦产业和加工企业进行实地调查,委托亳州市农业局和农业科学院组织主题为小麦生产和消费的座谈会,收集小麦种植品种、种植面积以及产量等相关数据,分析小麦产业化发展现状及现存主要问题。结果 亳州市形成以优质强筋小麦、中强筋小麦、中筋小麦为主,弱筋小麦为辅的种植结构,2019年优质专用小麦种植面积占小麦总面积69%。现有规模化面粉企业28家,合计年加工小麦约200万t,消费当地近60%的小麦。小麦产业发展过程中存在“农业合作社规模较小,种植规模和专业技能不足”“订单农业较少,小麦优质不优价”“面粉企业规模较小,下游食品加工企业少”“产业链间的融合不够紧密”等问题。结论 提出“构建大规模小麦加工体系,发挥龙头企业的产业带动作用”“发展农业专业合作组织,实现规模化、标准化、专业化种植”“研发优质品种配套栽培技术,实现良种良法”“打造优质专用小麦生产示范区,培育区域品牌”等策略建议。     

试论政府审计对行政权力的监督和制约——兼论政府审计职能定位

本文从加强对行政权力的监督和制约的必要性及我国行政权力监督和制约机制的现状分析入手，通过对政府审计在对行政权力的监督和制约中所发挥的作用的研究，提出了应对政府审计的职能进行重新定位的观点，并对进一步发挥政府审计的职能作用进行了探讨。     

制造业产业集聚如何影响生态环境

以产业集聚外部性效应为视角,利用2010-2016年天津市南港工业园、逸仙科学工业园、现代产业园与微电子工业园4个制造业产业园区面板数据,实证分析产业集聚与生态环境的双重效应关系,揭示其内在作用机制。结果表明：制造业产业集聚对生态环境存在正负两种外部性效应,具体作用取决于绿色技术创新与外商直接投资两个中介变量。当产业集聚水平较低时,绿色技术创新在制造业产业集聚对生态环境的影响关系中作用不明显。外商直接投资在制造业产业集聚与生态环境关系中起中介作用,即制造业产业集聚会加大外商直接投资规模,对生态环境产生消极影响;当产业集聚水平较高时,绿色技术创新在制造业产业集聚与生态环境的关系中起中介作用,即制造业产业集聚提高了绿色技术创新水平,对生态环境具有积极影响。外商直接投资在制造业产业集聚与生态环境关系中的作用不显著。     

长江干流地区跨世纪交通运输网络建设的总体构想

长江干流地区自宜宾至上海长约２８００ｋｍ，横跨中国东、中、西三大经济地带，面积占全国４．３％，有十分重要的战略意义。今后这一区域路网建设的目标是建成以长江干线为主轴，以宜宾、重庆、万县、枝城、武汉、丸江、芜湖、南京、江阴为结点的＂九纵一横＂的路网格局。长江干线包括加深长江航道，建设沿江铁路和沿江高等级公路。同时加强纵向铁路、公路和水运干线建设，形成若干水陆交通枢纽，并加强干线和支线机场建设，在上海、南京、武汉、重庆建成国际航空港。