要科学制订我国科技部门统计机构发展对策

1985年全国科技统计普查以来,科技行政部门科技统计工作逐步形成了自上而下的完整体系。具体来讲,国家科技部通过地方各级科技行政管理层设立的对口机构,将统计制度贯彻下去,再将统计资料回收上来,运用本部门的管辖权对调查对象施行行政制约,保障统计过程的有效运转。目前,科技部科技统计工作初步形成了以科技部发展计划司牵头,以科技统计分析中心、科技统计信息中心和科技指标研究会等为支撑力量的工作体系。从1990年代中后期以来,各省市科技管理部门也成立了多种形式的科技统计机构,将直接调查的职能从政府部门中剥离出来,建立相对独立的…     

Model Uncertainty and Bayesian Model Averaged Benchmark Dose Estimation for Continuous Data

The benchmark dose (BMD) approach has gained acceptance as a valuable risk assessment tool, but risk assessors still face significant challenges associated with selecting an appropriate BMD/BMDL estimate from the results of a set of acceptable dose‐response models. Current approaches do not explicitly address model uncertainty, and there is an existing need to more fully inform health risk assessors in this regard. In this study, a Bayesian model averaging (BMA) BMD estimation method taking model uncertainty into account is proposed as an alternative to current BMD estimation approaches for continuous data. Using the “hybrid” method proposed by Crump, two strategies of BMA, including both “maximum likelihood estimation based” and “Markov Chain Monte Carlo based” methods, are first applied as a demonstration to calculate model averaged BMD estimates from real continuous dose‐response data. The outcomes from the example data sets examined suggest that the BMA BMD estimates have higher reliability than the estimates from the individual models with highest posterior weight in terms of higher BMDL and smaller 90th percentile intervals. In addition, a simulation study is performed to evaluate the accuracy of the BMA BMD estimator. The results from the simulation study recommend that the BMA BMD estimates have smaller bias than the BMDs selected using other criteria. To further validate the BMA method, some technical issues, including the selection of models and the use of bootstrap methods for BMDL derivation, need further investigation over a more extensive, representative set of dose‐response data.     

血墨丹青--恽寿平生平艺术初探

清代初期画坛六大家之一的恽寿平,早年抗清,失败后誓不入仕,隐居武进老宅,倾情诗书画,既为谋生,亦是萌志。中年赁居常州城中白云溪畔,先借画室,后扩为家,并终老于此。文章阐述了他与另一书画大师王翚艺术互慕、事业相助的终生友谊,总结了其绘画艺术特色,即独创“没骨花卉”技法,并引领“常州画派”风靡清代早中期神州画坛。     

刘勰的文学观念——兼论所谓杂文学观念

刘勰在《文心雕龙》中所展示的文学观念 ,说明他能够从人类文化发展的角度 ,来认识文学的本质和特点。他既看到文学作为人类文化中的一个部分 ,具有人类文化的普遍共性 ,即也是“道之文” ,是具有客观真理性的自然之道的体现 ,同时又和人类文化中其他部分 ,如哲学、历史、政治、伦理道德等 ,具有根本不同的特点 ,它是艺术思维的产物 ,是人的感情的形象表现 ,是以语言为工具的审美的艺术品。刘勰和六朝时许多文学批评家一样 ,清楚地看到了那种宽泛的“文”的观念是不科学的 ,他们一直在用各种方式 ,试图寻找和探讨艺术文学 ,也就是所谓纯文学的特征 ,所以 ,简单地不加分析地肯定所谓“杂文学”观念 ,甚至把它说成是中国古代文学的民族特点 ,是不正确的     

Can the minimum living standard guarantee scheme enable the poor to escape the poverty trap in rural China?

The rural Minimum Living Standard Guarantee (Dibao) Scheme is the most important social assistance programme in rural China. However, how the rural Dibao programme affects household expenditures and whether it can enable the poor to escape the poverty trap are questions that remain largely unexplored. This study used data from the 2012 Rural Household Survey in China to investigate the impact of the rural Dibao programme on household expenditures. We found that the programme significantly improved the well‐being of low‐income households. Particularly, the programme significantly increased household expenditures on housing, education and health; furthermore, the impact was greater for households with educated household heads. However, the programme did not significantly affect household expenditures on food, transportation or farming inputs. The results imply that participation in the rural Dibao programme induces household investment in human capital, which could help to break the inter‐generational transmission of poverty and raise long‐run welfare.     

Family Control and Stock Market Reactions to Innovation Announcements

Although family firms are common around the world, studies on family‐controlled business are limited. Prior studies mainly focused on the influences of family ownership on overall firm performance, and the results were mixed. In this study we attempted to explore the impacts of family ownership on innovation by examining the association of family control and stock market reactions to innovation announcements. We found that firms with greater family control experienced significantly more negative stock market reactions to innovation announcements. The results further indicated that divergence of cash flow and voting rights was strongly and negatively correlated with announcement‐period abnormal returns. In addition, the findings suggested a significantly positive moderating effect of institutional ownership. The conclusions were robust under various measures of family control, and remained valid after controlling other influential factors for stock market reactions to innovation announcements.     

Price Incentives and Coordination in a Two‐Product Decentralized Supply Chain

We investigate pricing incentives for competing retailers who distribute two variants of a manufacturer's product in a decentralized supply chain. Under a two‐dimensional Hotelling model, we derive decentralized retailers' prices for the products, and distortions in pricing when compared to centrally optimal prices. We show that price distortions decrease as consumers' travel cost between retailers increases, due to less intense competition. However, price distortions do not change monotonically in consumers' switching cost between products within stores. To fix decentralized retailers' price distortions, we construct a two‐part pricing contract that coordinates the supply chain. We show that the coordinating contract is Pareto‐improving and analyze increase in the supply chain profit under coordination.     

销售时信息披露的公平原则与互利原则

本文通过对销售商向消费者披露产品的信息的责任和义务的分析,比较了信息披露道德的公平原则和互利原则.指出了信息披露的伦理要求,应根据各种具体问题的不同适当地在公平原则和互利原则之间定位.     

Variability explained by covariates in linear mixed‐effect models for longitudinal data

Variability explained by covariates or explained variance is a well‐known concept in assessing the importance of covariates for dependent outcomes. In this paper we study R² statistics of explained variance pertinent to longitudinal data under linear mixed‐effect models, where the R² statistics are computed at two different levels to measure, respectively, within‐ and between‐subject variabilities explained by the covariates. By deriving the limits of R² statistics, we find that the interpretation of explained variance for the existing R² statistics is clear only in the case where the covariance matrix of the outcome vector is compound symmetric. Two new R² statistics are proposed to address the effect of time‐dependent covariate means. In the general case where the outcome covariance matrix is not compound symmetric, we introduce the concept of compound symmetry projection and use it to define level‐one and level‐two R² statistics. Numerical results are provided to support the theoretical findings and demonstrate the performance of the R² statistics. The Canadian Journal of Statistics 38: 352–368; 2010 © 2010 Statistical Society of Canada     

论商业信用投融资决策

商业信用对提供者而言是一种投资活动 ,对接受者来说是一种融资活动。商业信用作为企业间相互融通资金的一种重要手段 ,其在为企业带来利益的同时 ,也需企业付出一定的代价。所以企业在采用商业信用投融资时需根据成本—效益原则进行决策