汉诺坝玄武岩中麻粒岩捕虏体的发现

近十余年来,中外地质学家对我国河北西北部的汉诺坝玄武岩及其深源包体进行了广泛深入的研究,发现了种类繁多的上地幔岩石捕虏体,发表了不少专著和论文,但有关麻粒岩捕虏体的报导,迄今为止尚未见到。本文作者经过三年的努力,在汉诺坝玄武岩中发现了五类八种麻粒岩捕虏体,其中包括石榴辉石麻粒岩、斜长石榴辉石麻粒岩、斜长单辉麻粒岩、斜长二辉麻粒岩、石榴钾长石英麻粒岩、石榴斜长石英麻粒岩、辉石二长麻粒岩、辉石钾长麻粒岩。初步研究表明这些麻粒岩大部分是在下地壳环境下形成的,它们具有麻粒岩矿物组合和结构构造特征,但又不完全类同于古老高级变质地体中的麻粒岩。     

涉外税收支出与国民待遇原则

国民待遇原则与涉外税收支出是一对矛盾的统一体.国民待遇原则要求的是内外平等对待,一视同仁,涉外税收优惠却是一种不平等对待和非一视同仁.二者所以共存,在于它们的统一性,即统一于对外国资本或外资企业税收待遇的非歧视.这种对立统一关系体现了税收效率与公平原则对立统一的内在要求.对于一国税制来说,国民待遇原则与涉外税收优惠两者的倚轻倚重则取决于该国经济发展的水平和客观的经济环境.     

征税成本领先性假设与中国税务组织结构优化——兼析中国国税、地税机构是否存在合并趋势

本文从征税成本领先性假设出发探讨了中国税务组织结构的优化问题 ,并分析了社会各界广泛关注的中国国税、地税机构是否存在合并趋势的问题。本文在对中国现行税务组织机构运行绩效考察的基础上 ,发现中国征税成本曲线呈抛物线状 ,表明中国征税成本正呈递减趋势。以此为出发点 ,本文详细论证了中国国税、地税机构不存在合并的趋势 ,相反 ,分设更为彻底却是今后的发展趋势 ,得出了与一般看法不同的结论 ,并对优化中国税务组织结构提出了政策建议     

Environmental Product Differentiation and Environmental Awareness

In this paper, we have considered a duopolistic model of environmental product differentiation with two types of consumers (green and brown) to analyze how environmental awareness affects the environment. “Green” consumers value the physical and environmental attributes of the good they purchase while “brown” consumers only value the physical attributes. We find that more environmental awareness may not be good news for the environment as the firm that produces the good without environmental attributes may increase its sales. The result depends on the degree of product differentiation and the cost to achieve it. Social welfare can also be inversely related to environmental awareness if the negative environmental effect dominates the positive market effect.      

An Eclectic Approach to Estimating U.S. Potential GDP

Rennison (Comparing alternative output gap estimations: a Monte Carlo approach, 2003) has provided simulation-based evidence showing that the joint use of extended multivariate filters and structural vector autoregression models is optimal for estimating potential output. We use this approach to estimate the two components of potential GDP: the full-employment labour input and trend labour productivity. This decomposition is useful for identifying sources of fluctuations in potential output. It reveals, for example, that the vigorous growth rate of U.S. potential GDP recorded during the second half of the 1990s is attributable to a fall in the structural rate of unemployment and a marked upswing in trend productivity growth.     

影响农村三种非农就业途径的主要因素研究--对天津市农村社会的实证分析

文章探讨了影响农村劳动力非农就业倾向的主要因素。研究结果表明,区位条件对农村劳动力非农就业倾向的影响,主要表现为近城地区以大量企业及相对发达的各种要素市场为第一优势,吸纳了更多劳动力进入本地企业就业。教育总体上是影响农村劳动力非农就业倾向的最重要因素。但其在近城地区的影响却位居第二。在远城地区教育对增大农村非农就业倾向的作用更为显著,而且受教育程度越高这种倾向就越显著。各种文化水平的影响都普遍促进了劳动者到外地企业就业,但对进入本地企业就业和家庭非农经营的促进却并不普遍,其中初中教育对农民在本地企业就业的作用更显著些;高中教育提高农民从事非农家庭经营的倾向最为明显。耕地数量抑制农户劳动力外出务工,但对其在本地企业就业和家庭非农经营的影响也不显著。乡镇企业的发展增大了农民进入本地企业的就业倾向,劳动者供养的非劳动人口数量对农民非农就业的正向影响不显著,农户拥有的非农业和农业生产性资产对农村非农就业的影响不大。因此,加快推进农村城镇化;加强边远农村地区的中等教育,特别是职业技能教育;大力发展乡企和私企;完善农村社会保障体系;构建农村劳动供求信息系统等,是促进农村劳动力加速向非农产业转移的重要途径。     

Exploitation and time

This paper analyses exploitation and class formation in a dynamic context. An intertemporal model of a subsistence economy is set up and, among other results, it is proved that, in an interior equilibrium, Differential Ownership of (Scarce) Productive Assets is an inherent feature of a capitalist economy, while exploitation tends to disappear in the long run. Asset inequality is therefore proved to be a normatively secondary (though causally primary) wrong. It is also argued that these results raise several doubts about the possibility of providing robust micro-foundations to Marxian concepts by means of Walrasian general equilibrium models.     

Building the Knowledge Stock: Lags,Depreciation, and Uncertainty in R&D Investment and Link with Productivity Growth

The search for an appropriate methodology to investigate the relation between R&D investment, knowledge stock and productivity growth is the main purpose of the paper. In analogy with physical assets, we present a model of knowledge capital formation which allows the calculation of the relevant user cost, as well. The proposed model accumulates R&D investment based on a stochastic gestation lag and a geometric depreciation of the stock. The basic parameters underlying the lag structure differ according to the types of research expenditure. The approach is applied to public R&D investment in Italian agriculture; the results provide interesting information about the economic structure of public research effort in Italian agriculture and plausible estimates of its internal rate of return.     

社科联在理论创新中要有更大作为

今年是我国加入世贸组织的第一年，是党的十六大召开的喜庆之年，也是我省贯彻落实省第十次党代会精神的第一年。做好今年的工作，意义重大，责任重大，使命重大。作为意识形态领域的重要组成部分，哲学社会科学界肩负着重要的责任，承担着重要的任务。社科联要以江泽民同志“     

Misperceiving the value of information in predicting the performance of others

Economic models typically allow for “free disposal” or “reversibility” of information, which implies non-negative value. Building on previous research on the “curse of knowledge” we explore situations where this might not be so. In three experiments, we document situations in which participants place positive value on information in attempting to predict the performance of uninformed others, even when acquiring that information diminishes their earnings. In the first experiment, a majority of participants choose to hire informed—rather than uninformed—agents, leading to lower earnings. In the second experiment, a significant number of participants pay for information—the solution to a puzzle—that hurts their ability to predict how many others will solve the puzzle. In the third experiment, we find that the effect is reduced with experience and feedback on the actual performance to be predicted. We discuss implications of our results for the role of information and informed decision making in economic situations. Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s10683-006-9128-y. JEL Classification C91, D83