Does Social Media Get Your Attention?

The author investigates how social media affects stock prices and post–earnings announcement drift in response to companies’ quarterly earnings announcements. Using quarterly earnings data as well Twitter and StockTwits data, the author utilizes Twitter volume and a residual methodology to generate an attention proxy that is orthogonal to the growth of Twitter accounts. The author finds that the new attention brought by social media after the earnings announcements positively affects the cumulative abnormal returns. Further, even companies reporting bad news can still have positive immediate cumulative abnormal returns if they attract enough attention from investors after an earnings announcement. The new attention effects are different in both magnitudes and statistical significance between social media popular and unpopular industries.     

基于多源数据融合的地表覆盖数据重建研究进展综述

地表覆盖数据对于全球环境变化、生物多样性和发展政策制定有着重要意义。遥感已成为获取地表覆盖数据的重要手段。而目前的地表覆盖数据产品,如Globe Land30、FROM-GLC、MODIS Collection5、MODIS Cropland、Glob Cover、GLC2000等,存在数据精度不高、数据间一致性较差、与统计数据差异较大等问题。因此,基于多源数据融合的数据重建方法成为目前研究中的热点问题。文章检索了近10年关于多源数据融合在地表覆盖数据重建中的应用的相关文献,概括了多源数据在数据重建中的应用现状,并对基于多源数据融合的地表覆盖数据重建方法进行了归纳总结,重点评述了不同方法的特点及应用情况,阐明了各种方法的优势与不足,同时对存在的问题进行探讨并展望了未来基于多源数据融合的地表覆盖数据重建研究的发展方向。基于多源数据融合的数据重建方法包括基于多源遥感数据融合法以及基于多源遥感和非遥感数据融合法。该文在对基于多源遥感数据融合的数据重建方法进行论述时,主要讨论了其中应用最广泛的两种融合方法:基于数据一致性的融合法和基于回归分析的融合法。对于其他基于多源遥感数据融合的数据重建方法,如基于D-S证据理论融合法、基于数据集成融合法、基于统计模型融合法,也列举了最具代表性的相关文献进行论述。在对基于遥感数据和非遥感数据融合的数据重建方法进行论述时,主要讨论了其3种空间分配方法:完全依赖法、部分依赖法、动态依赖法。在对目前研究进行探讨的过程中,该文对其研究区域、数据源、地表覆盖类型、空间分辨率、融合方法和文献来源进行总结分析,并重点就融合方法展开讨论。围绕各种融合方法在数据重建中的运用,该文归纳出目前研究中存在的主要问题:研究对象和区域上的不足,研究区多为全球及欧美,其他区域的研究过少,研究对象多为所有地表覆盖类型和森林,对耕地和草地的研究过少;融合算法上的不足、重建结果精度上的不足。最后,指出基于多源数据融合的数据重建方法未来的发展方向,即综合运用两类方法,得到具有详细完整空间信息的长时间序列的地表覆盖数据集。     

Environmental Innovations and Internationalization: Theory and Practices

Based on original data on Italian firms specializing in medium‐ and low‐tech industries, we study the relationship between firms’ upstream and downstream internationalization and their propensity to introduce products or processes that reduce environmental impact. Preliminary evidence suggests that geography plays an important role in green firms’ activities and supply chains. More precisely, results suggest that firms that outsource to and rely on non‐local suppliers are less likely to engage in environmental innovations. Moreover, we verify that firms engaged in export activities play a similar and negative role, regardless of the export intensity and typology of foreign markets (i.e. developed versus emerging). Tapping global flows of knowledge by being a part of a multinational group positively spurs the development of green innovations, as for FDIs. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment     

Moving beyond the tensions in open environmental innovation towards a holistic perspective

This paper analyses factors determining open environmental innovation (EI) and explores the possibility of embracing their tensions to achieve integrated environmental strategic goals. Building on recent literature linking open innovation and EI, the study assumes open EI strategic goals as a multidimensional construct based on the “synergistic and interwoven nature” of four identified enabling factors, that is, partners, knowledge, benefits, and motivations. A fuzzy‐set qualitative comparative analysis (fsQCA) based on Boolean algebra is conducted to analyse a set of 186 European companies operating in the telecommunication and information and communication technology (ICT) service industries. Making important theoretical, managerial, and policy contributions, this paper offers insights into the key factors enabling open EI and the tensional relationships within and between them. In doing so, it captures the non‐linear effects among these factors and the strategic goals related to an open EI strategy. It also suggests how the paradox theory might help in addressing the tensional dilemma of open EI strategy.     

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。     

调整燃烧降低飞灰含碳量

飞灰含碳量对火电厂经济运行有重要影响。本文主要研究通过对电厂锅炉燃烧方式的运行调整提高锅炉的效率和经济性的措施和方法。     

高职院校教学管理方法和管理人员的思考与研究

教学管理是高职院校教育管理的一项重要的核心内容,而教学管理人员则是高职院校教学管理的直接参与者和执行者。本文分析了现阶段高职院校教学管理人员的管理现状,提出高职院校管理人员所需的素质和一系列管理方法的创新手段,旨在使教学管理方法上升到"科学、轻松、高效"的台阶。     

城市轨道交通融资模式要素:从理论到实践

城市轨道交通融资模式组成要素与分类方法的标准化是模式比选和决策的基础。通过相关理论分析、总结实践做法等方式识别轨道交通可行的融资模式。采用的理论工具包括项目区分理论、公共物品理论等,案例包括伦敦、巴黎、北京等国内外13个城市和北京4号线、深圳4号线等应用创新性融资模式的具体项目。然后基于识别的融资模式总结轨道交通融资模式的四个主要组成要素,即投资主体、运营主体、资金来源和政府支持方式,并分别归纳出每个要素包含的不同备选方案,组成融资模式比选库,进而建立了城市轨道交通融资模式的一种标准化分类方法。所有融资模式可以通过形如AiBiCiDi的四要素方案构成进行描述和区分,为融资模式评价与比选的研究与实践提供参考依据。     

“Relative Importance of Risk Sources in Insurance Systems”, Edward W. Frees,April 1998

Abstract

This paper considers a Sparre Andersen collective risk model in which the distribution of the interclaim time is that of a sum of n independent exponential random variables; thus, the Erlang(n) model is a special case. The analysis is focused on the function φ(u), the expected discounted penalty at ruin, with u being the initial surplus. The penalty may depend on the deficit at ruin and possibly also on the surplus immediately before ruin. It is shown that the function φ(u) satisfies a certain integro-differential equation and that this equation can be solved in terms of Laplace transforms, extending a result found in Lin (2003). As a consequence, a closed-form expression is obtained for the discounted joint probability density of the deficit at ruin and the surplus just before ruin, if the initial surplus is zero. For this formula and other results, the roots of Lundberg’s fundamental equation in the right half of the complex plane play a central role. Also, it is shown that φ(u) satisfies Li’s (2003) renewal equation. Under the assumption that the penalty depends only on the deficit at ruin and that the individual claim amount density is a combination of exponential densities, a closed-form expression for φ(u) is derived. In this context, known results of the Cauchy matrix are useful. Surprisingly, certain results are best expressed in terms of divided differences, a topic deleted from the actuarial examinations at the end of last century.