基于ESDA-GWR的粮食单产及其驱动因子的空间异质性研究

在耕地面积扩展有限和城市化高速发展的背景下,粮食单产的区域差异对我国粮食安全具有重要意义。以我国31省（市、自治区）为研究单元,借助ESDA和GWR模型,结合我国各地自然条件的差异及其经济发展类型,揭示我国粮食单产的区域差异及其驱动因子的空间异质性。结果表明：1999—2008年,中西部地区粮食单产的增产对全国粮食产量的贡献越来越显著,75%的粮食单产增长潜力较大的区域集中在中西部;粮食单产存在着显著的空间相关性,各省域粮食生产重心发生移动,由传统的＂东部为主＂逐渐＂北上西进＂,向中西部地区欠发达省份集中;不同区域粮食单产的驱动因素呈现为一种非均衡联动的局域性特征,化肥施用量对粮食单产的影响在两个时间断面中差异最大,1999年回归系数全为正值,而在2006—2008年出现负值,这表明部分地区化肥对粮食单产的边际效应已经达到递减阶段。因此,应结合我国不同区域当前粮食单产的现状和驱动因子的效应机理,积极采取相应的有效措施以保障我国的粮食安全。     

云南省粮食生产波动及其影响因素实证分析

本文利用波动系数分析了云南粮食生产的产量波动情况,分析结果显示,云南省粮食生产波动的特征属于古典型波动,即波动系数小于零,而且波动频繁、波动幅度较大.同时对波动因素进行了分析,结果显示云南粮食总产量循环波动主要是由单产波动引起的,但是单产对总产的影响越来越小,而粮食播种面积对总产的影响越来越大,这说明确保粮食播种面积对稳定粮食产量意义重大.     

我国粮食生产补偿政策对粮食生产的影响

运用DEA方法测算2004—2011年我国粮食生产补偿政策的效率。结果显示:我国粮食生产补偿政策的实施对粮食生产效率提高的影响并不显著,且呈反复波动趋势。根据我国分地区逐步推进粮食生产补偿政策实施的特征,运用双差分模型对我国粮食生产补偿政策的实施效果进行评价,分析了其对粮食产量增长的政策影响。结果显示,我国粮食补贴政策对粮食产量的提高有正面效应,但其长期效应有待研究。     

建议多措并举提高中低产田产量保证粮食安全

粮食增产只有三条路,一是多种多收、靠扩大面积增产;二是多种多收和增产增收结合,即扩大面积的同时也提高单产;三是提高单产实现增收,一般规律是先走第一步,再走第二步,必然走到第三步。随着种植结构的调整,我市粮食种植面积不可能再大幅度增加,可以肯定,今后粮食增产的途径只有靠提高单产,究竟如何提高单产,大量生产实践证明:一是高产区要"高产再高产"难度很大、风险也很大、但效益却不大;二是中低产区只要解决生产中的一两个关键性技术问题,单产就会大幅度提高,用隆阳区的三个生产实例作说明。这不仅是对粮食生产的认识问题,而且也是生产策略问题和方法问题。因此建议,确保保山市粮食安全的指导思想应该是:稳住高产,提高中产,主攻低产。     

我国粮食综合生产能力的实证研究

文章运用1983～2005年我国粮食生产的有关数据,选取粮食播种面积和粮食单产这两个最主要的指标对我国粮食综合生产能力进行分析,认为我国粮食生产仍处于规模收益递增阶段,单产是影响我国粮食综合生产能力最主要的因素,其次是粮食播种面积,农业的抗灾能力对粮食生产的影响不显著.因此,提高我国粮食综合生产能力最根本的途径是加大对粮食生产的投入,依靠科技提高单产水平,提高粮食复种指数,同时加强农业抗灾能力建设.     

当前我国粮油等生活必需品保供稳价所面临的形势

2004年以来的粮食生产"七连增"使我国粮食供给达到历史最好水平;2011年粮食生产预计实现"八连增",进一步增加国家粮食安全的基础,为实现全年粮食供求基本平衡提供了重要保障,为稳定整体物价水平提供了有利条件。但是,也要看到,在粮食生产受到制约因素越来越多、粮食需求持续刚性较快增长的背景下,我国粮     

鄱阳湖生态经济区粮食单产时空格局演变及驱动因素探究

运用鄱阳湖生态经济区2001—2014年粮食生产面板数据,采用变异系数法、探索性数据分析(ESDA)方法以及地理加权回归(GWR)模型,分析鄱阳湖生态经济区粮食单产时空格局演变情况及驱动因素的空间异质性。结果表明:鄱阳湖生态经济区粮食单产年际间有所波动,但整体呈快速上升态势,粮食单产变异系数呈先波动下降后持续上升特征。鄱阳湖生态经济区粮食单产具有较强的全局空间相关性;粮食单产处于高—高地区和低—低地区的县(市)较多,处于高—低地区和低—高地区的县(市)较少;2001、2014年种粮人口规模、有效灌溉面积占比、农业机械总动力、农村用电量、农用化肥折纯量对鄱阳湖生态经济区粮食单产驱动作用存在较大空间异质性。     

京津冀地区粮食产量变化及其作物结构分析

基于京津冀地区及所辖的162个县域的粮食产量数据和主要粮食作物的产量数据,综合运用重心迁移模型和对数平均迪氏分解模型揭示1990—2010年间粮食产量的变化特征及其主导因素。结果表明:1京津冀地区粮食产量增加了521.09万t,玉米和小麦的增产效应明显。2粮食产量重心与粮食播种面积重心呈现"南进西移"的态势,粮食单产对粮食产量的正向促进作用显著。小麦单产的正向效应最显著,玉米次之,大豆和其他作物的单产效应较低;玉米播种面积的正向效应最显著,其他作物播种面积的负向效应明显。玉米播种面积的显著扩大与小麦单产、玉米单产的快速提升是研究期内京津冀地区粮食总产量增加的主要因素。3稻谷、小麦、玉米和大豆的播种面积与单产效应存在明显的空间差异:小麦播种面积和小麦单产的协同增长使冀中南平原区的小麦生产优势凸显;玉米播种面积和玉米单产的显著增长使海河冲积平原区和太行山山前平原区的粮食产量明显增加。     

安徽省农户粮食生产潜力——基于909名农户的调研数据

利用对粮食主产省之一——安徽省的农户所做调研的数据,假设粮农将所有的闲置耕地全部用来满负荷生产粮食,且粮食单产达到本村庄近五年内的最高产量,测得安徽省户均有45%的增产潜力;若上述假设条件不变,进一步假设安徽省南部的三季生产区只生产两季,则粮食增产潜力变为25%;在上述假设的基础上,再考虑气候对粮食单产的负面影响,则该比例变为11%。安徽省农户的粮食生产潜力之所以较大,是因为粮食的比较效益下降、农业基础设施较差、综合服务组织缺失和粗放式管理存在缺陷。最后提出保护和实现安徽省粮食生产潜力的对策。     

对影响我国粮食生产的因素分析及对策选择

文章采用计量经济分析方法,以1978—2004年中国粮食产量及其重要因素的时间序列为样本,对影响中国粮食生产的多种因素进行了分析。分析结果表明,近年来我国粮食生产主要受到单产提高缓慢、播种面积波动大、农业基础设施投入不足、自然灾害频繁等重要因素的影响。为提高粮食产量、促进粮食生产,首先应该提供一套促进粮食生产的政策措施,提高粮食种植效益,增加粮农收入是根本。在这个前提下,才有可能提高单产、稳定面积、加强基础设施建设、提高抗灾能力,增强我国粮食生产能力和生产稳定性。     

Forecasting the price of gold

This article seeks to evaluate the appropriateness of a variety of existing forecasting techniques (17 methods) at providing accurate and statistically significant forecasts for gold price. We report the results from the nine most competitive techniques. Special consideration is given to the ability of these techniques to provide forecasts which outperforms the random walk (RW) as we noticed that certain multivariate models (which included prices of silver, platinum, palladium and rhodium, besides gold) were also unable to outperform the RW in this case. Interestingly, the results show that none of the forecasting techniques are able to outperform the RW at horizons of 1 and 9 steps ahead, and on average, the exponential smoothing model is seen providing the best forecasts in terms of the lowest root mean squared error over the 24-month forecasting horizons. Moreover, we find that the univariate models used in this article are able to outperform the Bayesian autoregression and Bayesian vector autoregressive models, with exponential smoothing reporting statistically significant results in comparison with the former models, and classical autoregressive and the vector autoregressive models in most cases.     

Planned adaptation in risk regulation: An initial survey of US environmental, health, and safety regulation

In principle, we want regulatory programs to be based on current realities, as reflected for example in the best knowledge of relevant experts. That would imply that old rules now on the books should be consistent with today's knowledge base, not just what was known when a rule or standard was originally set. This paper reports on a survey of US programs, examining how often existing rules are actually updated in light of better knowledge, and identifies five programs that attempt to make policy routinely adaptive. These programs exhibit what we term Planned Adaptation: they both revise rules when relevant new knowledge appears, and take steps to produce such improved knowledge. While Planned Adaptation is rare, it is used in several nationally prominent programs, including air pollution, airplane safety, and drug safety. Planned Adaptation is a policy tool that deserves more attention.     

Pleasure and belief in Hume's Decision Process

Abstract

The purpose of this paper is to introduce explicitly pleasure and belief in what aims at being a Humean theory of decision, like the one developed in Diaye and Lapidus (2005a). Although we support the idea that Hume was in some way a hedonist – evidently different from Bentham's or Jevons' way – we lay emphasis less on continuity than on the specific kind of hedonism encountered in Hume's writings (chiefly the Treatise, the second Enquiry, the Dissertation, or some of his Essays). Such hedonism clearly contrasts to its standard modern inheritance, expressed by the relation between preferences and utility.

The reason for such a difference with the usual approach lies in the mental process that Hume puts to the fore in order to explain the way pleasure determines desires and volition. Whereas pleasure is primarily, in Hume's words, an impression of sensation, it takes place in the birth of passions as reflecting an idea of pleasure, whose “force and vivacity” is precisely a “belief”, transferred to the direct passions of desire or volition that come immediately before action. As a result, from a Humean point of view, “belief” deals with decision under risk or uncertainty, as well as with intertemporal decision and indiscrimination problems.

The latter are explored within a formal framework, and it is shown that the relation of pleasure is transformed by belief into a non-empty class of relations of desire, among which at least one is a preorder.     

The greenhouse effect: Damages,costs and abatement

The buildup of so-called greenhouse gases in the atmosphere — CO₂ in particular-appears to be having an adverse impact on the global climate. This paper briefly reviews current expectations with regard to physical and biological effects, their potential costs to society, and likely costs of abatement. For a worst case scenario it is impossible to assess, in economic terms, the full range of possible non-linear synergistic effects. In the most favorable (although not necessarily likely) case (of slow-paced climate change), however, it seems likely that the impacts are within the affordable range, at least in the industrialized countries of the world. In the third world the notion of affordability is of doubtful relevance, making the problem of quantitative evaluation almost impossible. We tentatively assess the lower limit of quantifiable climate-induced damages at $30 to $35 per ton of CO₂ equivalent, worldwide, with the major damages being concentrated in regions most adversely affected by sea-level rise. The non-quantifiable environmental damages are also significant and should by no means be disregarded.The costs and benefits of (1) reducing CFC use and (2) reducing fossil fuel consumption, as a means of abatement, are considered in some detail. This strategy has remarkably high indirect benefits in terms of reduced air pollution damage and even direct cost savings to consumers. The indirect benefits of reduced air pollution and its associated health and environmental effects from fossil-fuel combustion in the industrialized countries range from $20 to $60 per ton of CO₂ eliminated. In addition, there is good evidence that modest (e.g. 25%) reductions in CO₂ emissions may be achievable by the U.S. (and, by implication, for other countries) by a combination of increased energy efficiency and restructuring that would permit simultaneous direct economic benefits (savings) to energy consumers of the order of $50 per ton of CO₂ saved. A higher level of overall emissions reduction — possibly approaching 50% — could probably be achieved, at little or not net cost, by taking advantage of these savings.We suggest the use of taxes on fossil fuel extraction (or a carbon tax) as a reasonable way of inducing the structural changes that would be required to achieve significant reduction in energy use and CO₂ emissions. To minimize the economic burden (and create a political constituency in support of the approach) we suggest the substitution of resource-based taxes in general for other types of taxes (on labor, income, real estate, or trade) that are now the main sources of government revenue. While it is conceded that it would be difficult to calculate the optimal tax on extractive resources, we do not think this is a necessary prerequisite to policy-making. In fact, we note that the existing tax system has never been optimized according to theoretical principles, and is far from optimal by any reasonable criteria.During the academic year 1989–90 Dr. Ayres was at the International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.During the summer of 1989 Mr. Walter was a member of the Young Scientists' Summer Program at IIASA.     

Globalization,Neoliberalism and the attack on social security

Neoliberal political movements advocate privatization of public pension systems. Globalization imposes pressure on nations to conform to neoliberal policy views with respect to the design and structure of social insurance, including public pension systems. The paper begins with an investigation of the economic, ethical and ideological dimensions of the privatization debates in the U.S.; it argues that privatization advocates may be largely moved by ideology, since the other reasons advanced appear weak or unfounded. The second part discusses the history of Social Security, the purposes for its creation, and some of its economic effects. Differences between public and private pension systems are considered. A brief international comparison of some aspects of public pension system finance and benefit structures is presented. The final section considers the ethical, macroeconomic and distributional implications of privatization, prefunding and payroll tax funding, and argues for a pay as you go system financed with income taxes. In order to promote equity, economic security, community, and social cohesion, public pension systems should be universal in coverage. In order to reduce the inequality, income insecurity, and aged poverty generated by market economies, public pension systems ought to be progressive: benefit/contribution ratios should be inversely proportional to income, and progressive income taxes should finance the system. To promote economic growth, the systems should be financed on a pay-as-you-go basis, and should not be prefunded except for an emergency reserve. The fiscal policy recommendations partially depend upon the theory developed by Abba Lerner in the 1940s, and recently advanced by Wynne Godley and Randy Wray: Lerner's “principle of functional finance.”     

SCIENCE AND INDUSTRY: TRACING THE FLOW OF BASIC RESEARCH THROUGH MANUFACTURING AND TRADE

This paper describes flows of basic research through the US economy during the late 20th century. In addition, the paper studies the effect of the flows on scientific papers in industries and fields. This article differs from others in its use of measures of science rather than technology. Together, its results present a picture of the structure of basic research flows in a modern, science-intensive economy. Basic research flows are large within petrochemicals and drugs, and within software and communications. Flows of chemistry, physics, and engineering are common throughout all industries – biology and medicine are almost confined to petrochemicals and drugs; and computer science is nearly as restricted to software and communications. In general, basic research flows are more concentrated within scientific fields than within industries. Our findings concerning the production of scientific papers indicate that the effect of a 1% change in academic R&D spillovers significantly exceeds that of industrial spillovers. In addition, within-field effects exceed effects between-fields, while within- and between-industry effects are roughly equal. It follows that scientific fields limit basic research flows more than industries do, perhaps because large firms implicitly span a range of industries.     

Valuing Mangrove-Fishery Linkages – A Case Study of Campeche, Mexico

This paper explores the value of mangrove systems as a breeding and nursery habitat for off-shore fisheries, focusing on mangrove-shrimp production linkages in Campeche State, Mexico. We develop an open access fishery model to account explicitly for the effect of mangrove area on carrying capacity and thus production. From the long-run equilibrium conditions of the model we are able to establish the key parameters determining the comparative static effects of a change in mangrove area on this equilibrium. We then estimate empirically the effects of changes in mangrove area in the Laguna de Terminos on the production and value of shrimp harvests in Campeche over 1980–90. Our findings suggest that mangroves are an important and essential input into the Campeche shrimp fishery, but that the low levels of deforestation between 1980 and 1990 mean that the resulting losses to the shrimp fishery are still comparatively small. Over-exploitation of the fishery due to open access conditions remains the more pervasive threat, and without better management any long-run benefits of protecting mangrove habitat are likely to be dissipated.     

Interest on reserves and inflation

The payment of interest on reserves has been a common practice in inflationary economies. This policy may seem paradoxical since it involves returning part of the seigniorage, generated by the inflation process, with the intention to finance the fiscal deficit. This paper argues that the motivation for this policy can be captured by the discretionary regime, where the policymaker pays interest on reserves because he is concerned with the erosion of real liquidity by inflation, which is in part beyond his control. However, this policy is an unlikely outcome in the commitment regime, where the policymaker is in full control of inflation.     

An Economic Analysis and Simulation of Woodfuel Management in the Sahel

This paper presents an economic framework and a computationalmethodology for assessing the evolution of woodfuel supply costsand the spatial distribution of biomass in a Sahelian woodlandsetting. Spatial data on standing stock and the costs oftransport to market are used to construct a supply curve for fuelto a fuel-consuming location. Given an exogenously specifieddemand, the model simulates, period by period, the extraction,regeneration, and transport of wood fuels. The model is appliedto evaluate the benefits and ecological impacts of scenarios forwoodland management around the city of N'Djamena, Chad.