农机服务发展与粮食生产效率研究:2004—2016——基于变系数随机前沿分析

采用“两步法”研究了农机服务发展与中国粮食生产效率的关系.基于2004-2016年全国31省份粮食生产投入产出的面板数据,利用变系数随机前沿分析方法测算了中国粮食生产的技术变化、技术效率以及全要素生产率,然后构建农机服务发展影响粮食生产效率的OLS回归模型.结果表明:(1)31省份粮食生产的投入要素产出弹性和技术效率存在明显差异,2008年粮食技术变化最为明显,粮食全要素生产率的增长在2008年高达5%.(2)农机服务在2008年以后对粮食全要素生产率的增长具有显著的促进作用,农机服务对粮食TFP的作用存在一定的滞后效应.(3)农机服务发展与劳动产出弹性具有替代关系,与化肥和机械产出弹性具有互补关系.在三大粮食作物中,小麦机械化程度最高,水稻和玉米的机械化程度还有待提升.     

粮食生产水足迹动态演变及分解效应

基于水足迹方法构建粮食生产水资源匹配指数,从用水总量、来源结构和粮水匹配关系三个方面分析粮食生产用水的动态演变特征,并采用LMDI模型将粮食生产用水变动分解为9类效应,研究结果表明:粮食生产水足迹变动经历小幅下降——快速回升——企稳上升三个阶段,粮水匹配度较差且矛盾趋于激化。从分解效应看,三产结构调整和节水技术进步是减少粮食生产用水的主要因素,但种植结构调整以及用水效率改善未发挥预期节水效果,粮水匹配关系恶化、水土资源贫乏及二者匹配度较差均不利于缓解农业用水压力。     

粮食生产的能源投入及技术变动趋势

为探究中国粮食生产的能源投入及技术变动趋势,构建了粮食生产超越对数生产函数模型,基于全国30个省份面板数据进行实证分析。结果显示,化肥、农药、农用柴油等能源投入对粮食生产的影响较大,化肥、农药的边际作用呈递减趋势,劳动力、农用柴油、机械动力的边际作用呈递增趋势,各能源要素与劳动力的替代关系明显。为此,在中国未来的粮食生产中,要提高化肥、农药、农用柴油等能源要素的利用效率,通过技术创新提升农业机械动力、劳动力的生产贡献程度,推动粮食生产向精细化和能源节约方向转变。     

Inequality and demographic response to short-term economic stress in North Orkney,Scotland, 1855–1910: Sector differences

We examine economic inequality and social differences in infant and child mortality, and fertility responses to food price changes in North Orkney, 1855–1910, using linked vital records. This small population featured a diverse occupational structure, limited land resources, and geographic isolation from mainland Scotland. Segments of Orkney’s non-agricultural working population were living so close to the margin of subsistence in normal years that an increase in food prices in bad years cost the lives of their children. Delayed childbearing, in addition to increased labour intensity, occupational diversification, and poor relief, failed to mitigate the negative effects of unfavourable prices in this group. While previous studies for Western Europe show a strong social gradient in mortality responses to food prices, and for Eastern Asia a strong household gradient, this study shows a strong sectoral gradient, indicating low standards of living for the non-agricultural working population well into the twentieth century.     

以发展粮食产地加工转化促进河南县域经济发展

分析了发展粮食产地加工转化对其县域经济的促进作用、河南省发展产地加工转化的优势和方向。认为应围绕粮食经济发展,优先做好粮食产地加工转化,把粮食加工产业培育成河南省县域经济的主导产业。要把保障国家粮食安全与提高粮农收入有机联系在一起,加大对产粮大县的政策扶持。要在粮食生产基地建立起较为完备的加工体系,延伸产业链,以带动产粮大县发展经济、增加就业,推进工业化、城镇化、农业现代化深度融合和协调发展。     

中国饲料原粮供应模式分析

养殖业的发展对饲料的供应提出了数量、品质、时间等诸多要求,而占饲料成本80%的原料粮供应成为当前养殖业健康发展的瓶颈,面对我国部门分割、地区封锁严重,粮食流通不畅、粮食产业链短小等诸多问题,文章着重对当前饲料原粮供应的各种模式进行分析,并提出推广成功模式、创新供应链建设、协调原粮供应主体之间的关系以及加强粮食产销区合作的建议。     

Likelihood Inference for Unions of Interacting Discs

Abstract. This is probably the first paper which discusses likelihood inference for a random set using a germ‐grain model, where the individual grains are unobservable, edge effects occur and other complications appear. We consider the case where the grains form a disc process modelled by a marked point process, where the germs are the centres and the marks are the associated radii of the discs. We propose to use a recent parametric class of interacting disc process models, where the minimal sufficient statistic depends on various geometric properties of the random set, and the density is specified with respect to a given marked Poisson model (i.e. a Boolean model). We show how edge effects and other complications can be handled by considering a certain conditional likelihood. Our methodology is illustrated by analysing Peter Diggle's heather data set, where we discuss the results of simulation‐based maximum likelihood inference and the effect of specifying different reference Poisson models.     

首都粮食系统安全保障体系研究

分析了首都粮食流通体系的现状及问题，提出了建设首都粮食流通聚集区的设想，开展了必要性分析、立地与规模需求分析，提出了建设思路、运作模式和运营重点。     

International Trade and the Urbanization of Developing Countries: Evidence from Asia

Abstract

A grain surplus and the grain trade are closely related to the urbanization of developing countries. However, existing literature has not given adequate attention to this issue. Our paper develops a theoretical model to explain the mechanisms whereby changes in the grain surplus constrain the level of urbanization in a closed economy context and the grain trade affects the level of urbanization by acting on the grain surplus in an open economy context. A test of the theoretical model applied to some developing countries in Asia during the period 1993-2010 shows that international trade is generally negatively correlated with level of urbanization. However, cereal and non-cereal trade vary in terms of their relation to urbanization: whereas the former is positively correlated with level of urbanization, the latter is negatively correlated with it. Since the net import of cereals relaxes the constraint imposed on the level of urbanization by the domestic grain surplus, it can have a marked positive effect on the course of urbanization. Our research findings show that provided grain production or grain security is guaranteed, developing countries may adopt a policy of importing an appropriate amount of grain to increase their level of urbanization.     

绝地天通与中国政教结构的开端

五帝时代之所以作为中国史的开端,乃是基于如下的意识:作为中国传统的天下政教形态在五帝时代业已开端.它体现在帝与群神的二层级的政治构造上面;这一构造对应于三代王制中的天子与诸侯的共治结构;而在天下型国家成立之后,这一构造又变易为圣与王、君子与君主的共治结构,构成了中国两千年传统政教形态的典范.帝与群神的分工,导致了对民的统治被架置在文化上而不是狭义的政治上,初步展现了中国传统政教将政治镶嵌在文化中的基本精神.