美国中小学服务学习课程模式的理论与实践

服务学习是美国中小学广泛实施的一种优秀的实践教学课程模式。不同于单纯的社会体验或学科教学,服务学习将课程学习、社会服务和体验反思三者有机地结合起来,不仅加强了学生课堂所学知识与现实世界的关联,同时也极大地丰富了中小学生的社会实践活动。其基本理念、特征、实践模式及实施经验对我国当前基础教育课程改革有着很高的借鉴价值。     

永泰县城区空气中主要污染物类别及其影响因素分析

经监测,永泰县城区大气污染物主要为PMl0、PM2.5、O3,影响O3的因素主要有汽车尾气排放、日照,PMl0、PM2.5浓度大小除与车流量、烟花爆竹燃放相关外,还与降水、风速等气象因素密切关联。针对这些影响因素,该文提出了相应的防治措施。     

知识产权“十二五”发展规划实施的关键难题与机遇研究

知识产权＂十二五＂发展规划具有多重属性与复杂性、制定组织结构多元化、地区发展不平衡及其与环境匹配较难等特点,较薄弱的知识产权基础因素与国际发展动态影响下,使得我国知识产权＂十二五＂发展规划实施挑战与机遇并存。     

Second-Order Approximations to Two Classes of Sequential Estimation Procedures

For the model considered by Chaturvedi, Pandey and Gupta (1991), two classes of sequential procedures are developed to construct confidence regions (which may be interval, ellipsoidal or spherical) of ‘pre-assigned width and coverage probability’ for the parameters of interest and for the minimum risk point estimation (taking loss to be quadratic plus linear cost of sampling) of the nuisance parameter. Second-Order approximations are derived for the expected sample size, coverage probability and ‘regret’ associated with the two classes of sequential procedures. A simple and direct method of obtaining the asymptotic distribution of the stopping time is provided. By means of examples, it is illustrated that several estimation problems can be tackled with the help of proposed classes of sequential procedures.     

RAILROADS AND GROWTH IN PRUSSIA

We study the effect of railroad access on urban population growth. Using GIS techniques, we match triennial population data for roughly 1,000 cities in 19th‐century Prussia to georeferenced maps of the German railroad network. We find positive short‐ and long‐term effects of having a station on urban growth for different periods during 1840–1871. Causal effects of (potentially endogenous) railroad access on city growth are identified using propensity score matching, instrumental variables, and fixed‐effects estimation techniques. Our instrument identifies exogenous variation in railroad access by constructing straight‐line corridors between nodes. Counterfactual models using pre‐railroad growth yield no evidence to support the hypothesis that railroads appeared as a consequence of a previous growth spurt.     

MANAGED COMPETITION IN HEALTH INSURANCE

Rising healthcare costs have sparked debate about the best way to provide high‐quality affordable health insurance. We discuss the potential for regulated insurance markets to outperform single‐payer public insurance. We use as an example the private Medicare plans that now provide insurance to almost a third of seniors in the United States. The evidence suggests that private plans can limit costs and potentially appeal to enrollees, and that well‐designed risk adjustment can mitigate market failures due to adverse selection. However, fostering competition between insurers, especially in smaller markets, is difficult. We discuss how future research might illuminate the relative advantages of public and private health insurance.     

POLITICAL SELECTION IN CHINA: THE COMPLEMENTARY ROLES OF CONNECTIONS AND PERFORMANCE

Who becomes a top politician in China? We focus on provincial leaders—a pool of candidates for top political office—and examine how their chances of promotion depend on their performance in office and connections with top politicians. Our empirical analysis, based on the curriculum vitae of Chinese politicians, shows that connections and performance are complements in the Chinese political selection process. This complementarity is stronger the younger provincial leaders are relative to their connected top leaders. To provide one plausible interpretation of these empirical findings, we propose a simple theory in which the complementarity arises because connections foster loyalty of junior officials to senior ones, thereby allowing incumbent top politicians to select competent provincial leaders without risking being ousted. Our findings shed some light on why a political system known for patronage can still select competent leaders.     

Gender differences in risk behavior and the link to household effects and individual wealth

This study examined the differences in risk behavior between men and women using a household survey that captured the risk preferences of two members in a household and recorded wealth at the individual level instead of the usual approach of representing wealth at the household level. After controlling for commonly used explanatory variables, such as gender, education, age, and wealth, household fixed effects explain about 15% of the variation in risk behavior. This highlights the magnitude of household effects in shaping one’s risk behavior. In general, females in the study area are more risk averse than males based on a risk game with real payout. The gender differences disappear when focusing on only the top land owners. However, even in those cases, females consider themselves more risk averse, supporting results from previous studies that link culture and societal norms to the gender differences in risk behavior.     

新时代下物联网产业的发展困境与推进原则 —— 工信部《物联网“十二五”发展规划》解读

2012年2月14日,工业与信息化正式发布了《物联网“十二五”发展规划》,这是物联网首次国家层面上的产业整体发展规划。物联网产业是战略性新兴产业的重要一项,对于加快转变经济发展方式,推动相关产业转型升级具有重要作用。本规划的推出将会引导各级政府进行物联网产业发展布局,争取形成新一代信息技术产业发展的合力,推动我国经济在十二五阶段更快更稳发展。