Proactive R&D management and firm growth: A punctuated equilibrium model

The external environment is characterized by periods of relative stability interspersed with periods of extreme change, implying that high performing firms must practice exploration and exploitation in order to survive and thrive. In this paper, we posit that R&D expenditure volatility indicates the presence of proactive R&D management, and is evidence of a firm moving from exploitation to exploration over time. This is consistent with a punctuated equilibrium model of R&D investment where shocks are induced by reactions to external turbulence. Using an unbalanced panel of almost 11,000 firm-years from 1997 to 2006, we show that greater fluctuations in the firm's R&D expenditure over time are associated with higher firm growth. Developing a contextual view of the relationship between R&D expenditure volatility and firm growth, we find that this relationship is weaker among firms with higher levels of corporate diversification and negative among smaller firms and those in slow clockspeed industries.     

Competition,Concentration and Diversity in European Television Markets

This study investigates how competition, concentration and public broadcasters influence diversity of programme supply in European television markets. It focuses on free, national generalist channels; studies programmes as provided throughout the day; and tests hypotheses with data on Finland, France, Germany, Greece, Italy, the Netherlands, Spain and the U.K. for the late 1980s and 1990s. It concludes that competition is moderate in most markets. Under these conditions, competition and concentration contribute to a diverse supply of programmes that mirrors audience demand, while public broadcasters increase diversity of supply above competitive market levels.     

高校图书馆图书借阅集中与分散规律的实证研究及应用

简要分析高校图书馆借阅集中与分散现象的原因,通过实例统计数据对布鲁克斯公式的回归,证实高校图书馆借阅集中与分散十分类似于文献分布定律。最后对该规律作详细归纳与总结,引入核心系数（λ）与未用系数（δ）概念,结合实例讨论合理的λ与δ的取值范围,并进一步讨论根据核心区与外围区或未用区确定复本的方法。     

高等教育大众化中的高考制度改革——基于利益相关者理论的分析

在高等教育大众化的推动下,我国长期以来实施的全国统一的高考制度发生了局部变化,主要特征是开始由高度的统一性向多样化演变,由中央高度集权向地方分权转变。从利益相关者理论来看,这些变化是中央政府、地方政府、高等学校和广大考生四方利益博弈的结果,走向四方利益的均衡是高考制度改革和发展的方向。     

Banach不动点定理的推广及应用

本文主要讨论完备距离空间中Banach不动点定理,给出了定理的一些推广结果和改进形式,并举例说明了Banach不动点定理在经济上的应用。     

大学生心理现象及心理健康探究

中国传统文化蕴涵着当代大学生心理卫生和心理健康教育的深刻思想根基。只有扎根于历史文化沃土,弘扬传统精华,同时借鉴西方经验,才能创建出具有中国特色的、卓有成效的当代大学生心理健康教育理论和实践体系。发掘大学生心理健康教育的文化根基,不仅对正确认识和处理心理健康教育与德育、体育、美育之间的关系等一系列现实问题,而且对创立具有中国特色的当代大学生心理健康教育体系都具有重要的理论意义和实践价值。     

Optimizing neural networks by genetic algorithms for predicting particulate matter concentration in summer in Beijing

We developed and tested an improved neural network to predict the average concentration of PM10 （particulate matter with diameter smaller than 10 μm） several hours in advance in summer in Beijing. A genetic algorithm optimization procedure for optimizing initial weights and thresholds of the neural network was also evaluated. This research was based upon the PM10 data from seven monitoring sites in Beijing urban region and meteorological observation data, which were recorded every 3 h during summer of 2002. Two neural network models were developed. Model I was built for predicting PM10 concentrations 3 h in advance while Model II for one day in advance. The predictions of both models were found to be consistent with observations. Percent errors in forecasting the numerical value were about 20%. This brings us to the conclusion that short-term fluctuations of PM10 concentrations in Beijing urban region in summer are to a large extent driven by meteorological conditions. Moreover, the predicted results of Model II were compared with the ones provided by the Models-3 Community Multiscale Air Quality （CMAQ） modeling system. The mean relative errors of both models were 0.21 and 0.26, respectively. The performance of the neural network model was similar to numerical models, when applied to short-time prediction of PM10 concentration.     

制度转型的演化视角

经济演化理论为观察制度变革提供了一个有效的工具。制度转型是制度竞争过程、制度结构变化过程和制度均衡过程的统一,由此决定动态演化是实施并完成制度转型的常规形式。揭示制度演化的内在逻辑可以更加准确地把握制度变革规律,科学地设计制度变革路径,有效地推进制度变革进程。     

校际协作联盟：面向教育均衡发展的价值思考与构想——来自英国“连锁学校”的启示

均衡发展是我国当前义务教育的战略性任务,也是世界各国颇为重视的教育问题。通过分析我国校际教育不均衡的缘由,探究基于网络的校际协作在面向教育均衡发展中的潜在价值,在借鉴英国＂连锁学校＂的组织、运行及管理方式的基础上,提出在我国的中、小学校之间构建跨区域的＂校际协作联盟＂的构想,并对其内涵、特征及组织模式进行了探讨,最后从教育均衡的理念出发进行了必要的思考与讨论。     

浓缩与澄清─—两难问题浅析

固液分离过程中澄清与浓缩的两难问题由来已久．本文讨论了在使用高分子絮凝剂保证澄清效果的前提下如何提高浓缩产物的固体含量,同时设法改善浓缩物的性质使之便于进一步压缩处理的有关问题．文中论述了相关的研究结果、研究方法及潜在的研究方向．分析了聚集体尤其是絮凝体内液体介质的赋存状态,提出了改进絮凝物脱水的某些新机制．