Wood Fuel or Carbon Sink? Aspects of Forestry in the Climate Question

This paper discusses and contrasts two mainroles of forestry in light of the debate on theglobal climate. As the main problem is relatedto the increases of the CO₂-concentrationin the atmosphere, forests may be viewed aspart of the alleviation of the problem throughtheir function as (i) a source of biomass forenergy production, which may replace fossilfuels and thus indirectly reduceCO₂-emissions, and as (ii) carbon storage,since a growing forest extracts atmosphericCO₂ and fixes it as carbon in biomass. Inthe Scandinavian forestry, logging residues areincreasingly being used for energy production.In this paper the value of forests as a sourceof bioenergy is added to the traditional timbervalue. Formulated as a joint production modelwithin the Faustmann framework, the effect ofthis addition on the optimal rotation length isdiscussed. Based on data for spruce, thedominant species in the Scandinavian forestry,it is demonstrated that the rotation length isshortened compared to the standard Faustmannmodel. Shorter rotation length implies lesscarbon storage. Therefore, in this modelwithout explicit regard to the social carbonstorage value of the forest, the gains in termsof the climate problem from utilisation offorest biomass for energy production are beingdiminished by the value of reduced carbonstorage. The carbon value of the forest is thenadded to complete the model, with the effect ofincreasing the rotation length, a result thatis well known in the literature. Finally, theempirical effects of the interaction of thesetwo climate-related value elements of theforest are discussed.     

先进制造技术与生产流程的协同性研究

制造系统的有效性需要通过先进制造技术与生产流程的合理匹配来体现。在分析各种先进制造技术与生产流程相互关系的基础上,提出了协同度的概念,并给出了其计算方法。     

中国粮食生产区域分化特征和成因的实证研究

对中国在1990年和2002年粮食生产的区域分化状况进行统计分析的结果表明,工业化和城市化的发展,以及农产品市场形成条件下,稻米生产的区域分散特征、小麦生产的区域集中特征以及玉米播种面积的集中和生产产量的分散特征日益明显。计量检验显示,人均承包经营耕地面积和种植业收入比率是影响粮食生产区域分化的最主要的两个因素。     

中国国内生产总值与教育之间关系的实证分析

本文从柯布-道格拉斯生产函数入手,将劳动力按受教育程度划分为四类分别进行处理。主要就中国国内生产总值(GDP)与各等教育程度劳动力和投资之间关系进行单整和协整检验,并建立误差修正模型(ECM),然后在协整条件下对各等教育程度劳动力与GDP的长、短期关系进行分析。文章的实证结果将为我国有关部门的政策决策提供有力依据。     

A Stochastic Frontier Production Function with Flexible Risk Properties

This paper considers a stochastic frontier production function which has additive, heteroscedastic error structure. The model allows for negative or positive marginal production risks of inputs, as originally proposed by Just and Pope (1978). The technical efficiencies of individual firms in the sample are a function of the levels of the input variables in the stochastic frontier, in addition to the technical inefficiency effects. These are two features of the model which are not exhibited by the commonly used stochastic frontiers with multiplicative error structures.An empirical application is presented using cross-sectional data on Ethiopian peasant farmers. The null hypothesis of no technical inefficiencies of production among these farmers is accepted. Further, the flexible risk models do not fit the data on peasant farmers as well as the traditional stochastic frontier model with multiplicative error structure.     

Pure joint production and international trade: a note

This paper applies the principles of the neo-Ricardian (or Sraffian)theory of international trade to certain joint production systems.It is shown that, in contrast with single-product systems, (i)there is not always a pattern of international specialisation,which would entail the increase of the real wage rate in botheconomies, and (ii) the ‘law of comparative advantage’has no general validity. Furthermore, not only the existenceof such a pattern of specialisation but also the validity ofthis law depend on the values of the variables of distributionof income. The analysis is wholly based on two of the numericalexamples formulated by Bidard in 1997, and further generalisedin an elementary way only when this is considered necessary.     

Embedded industrial production systems: Lessons from waste management in zinc production

To meet the sustainability challenge private companies must implement corporate strategies and adopt novel technologies. The technical and social embeddedness of industrial production systems, however, complicates these systems' transition towards sustainability. In the paper, mechanisms and conditions are reported for the development and implementation of waste management options in embedded industrial production systems. The focus is on the Dutch zinc production industry, which had to deal with a major waste problem; the generation of jarosite. The industry's options were to increase the jarosite waste storage capacity, to develop a jarosite treatment process or to switch to a zinc-ore of low-iron content whereby no jarosite waste would be generated anymore. Required conditions appeared to be a combination of technological capability and technical embedding and favourable economics. Case study research, however, revealed that adequate stakeholder management is crucial to address social pressure exerted and to obtain external acceptance for any transition strategy. Whilst appropriate, internal technological capabilities are important, effective interactions with and enrolment of various firm-external actors are crucial. In the case of zinc, access to the heterogeneous external actor network was critical for the development of the jarosite treatment solution direction. In conclusion, both the technical, organizational and social embedding of new technologies are crucial for successful implementation.     

国外直接投资对中国地区经济发展的影响

用生产函数的衍生模型分别对中东、中、西部地区进行分析,在东部地区国外直接投资对经济发展的促进作用明显,而中、西部地区国外直接投资对其经济发展的影响不显著,表明我国地区之间的经济差异在很大程度上是由外商直接投资的区域差异引起的.     

基于人工神经网络的企业生产预警管理系统研究

企业生产预警管理是生产企业现代管理的一种新模式,它通过监测指标,对企业外部环境变化和生产管理活动进行综合评价,判断企业生产管理所处状态,并采取相应的预先控制对策,使企业生产管理活动始终处于“安全、有效”的管理模式。人工神经网络是广泛应用于众多学科的非线性模拟技术,文章将人工神经网络技术应用到企业生产预警管理中,根据影响生产管理的指标和分类标准随机生成有效的样本数据以建立人工神经网络模型。结果表明样本生成方法和应用人工神经网络技术进行企业生产预警管理评估的方法是合理并可行的。     

我国农产品物流落后原因初探

在我国，农产品物流很少有人关注，但是，由于农产品的物流落后使我国农产品的损失却大得惊人。这不仅极大地影响了农民收入水平的提高，还严重削弱了我国农产品的国际竞争力。本文对我国农产品物流落后的原因进行了全面、深入的探讨。