THE TERM STRUCTURE OF INTEREST RATES AS A GAUSSIAN RANDOM FIELD

A simple model of the term structure of interest rates is introduced in which the family of instantaneous forward rates evolves as a continuous Gaussian random field. A necessary and sufficient condition for the associated family of discounted zero-coupon bond prices to be martingales is given, permitting the consistent pricing of interest rate contingent claims. Examples of the pricing of interest-rate caps and the situation when the Gaussian random field may be viewed as a deterministic time change of the standard Brownian sheet are discussed.     

主动选择还是被动适应——农户秸秆还田驱动力探究

[目的]秸秆还田好处良多,但秸秆焚烧却屡禁不止。文章主要研究农户秸秆还田行为的长效性问题,考察农户的秸秆还田行为是主动适应还是被动选择。[方法]该文利用山东、湖北调研数据,采用二元Logistic模型实证分析了农户秸秆还田的影响因素以及这一行为的长效性。[结果](1)目前农户的秸秆还田行为还处于被动适应状态,农户对政府高压更为敏感;(2)提高农户对秸秆还田好处的认知将极大促进农户采纳秸秆还田技术;(3)政府高压和秸秆还田认知能显著提高男性农户的秸秆还田技术采纳行为;(4)提高女性农户对秸秆还田优点的认知能显著提高其对秸秆还田技术的采纳行为。[结论]政府在推动秸秆资源化利用的过程中,应"疏堵结合",通过强化技术支撑,实现秸秆还田技术配套措施的纵向一体化和秸秆还田方式的横向整合。通过加大宣传力度和注重群体导向等方式,实现农户认知水平和政策精度的提高,更好实现秸秆还田。     

Myopia and saliency in renewable resource management

An important challenge in managing renewable resources is to understand why owners and managers sometimes make decisions that deplete resources and future earnings, such as when graziers allow pastures and land condition to be degraded. In this paper, we test two potential reasons for unsustainable management practices, myopia and salience, with each explaining why resource managers may exhibit impatience in harvest decisions. Myopia is associated with decision makers placing lower weight on future outcomes than would be implied by their pure time preference. Salience is associated with overweighting of consumption ‘now’, implying inconsistency in time preferences. To test for these effects on renewable resource management, an incentivised, dynamic field experiment was carried out with rangeland grazing enterprise owners in north‐eastern Australia that related management choices with uncertain rainfall events to both profits and land condition over time. Results demonstrate that respondents exhibiting myopia/salience in their choices tended to achieve lower cumulative scores in the experiment, as well as lower land conditions on their properties as measured with remote sensing data. Our results explain why there may be persistent optimisation failures by resource owners that reduce both profits and environmental outcomes.     

日本森林保健旅游开发及研究进展

在新兴的森林保健旅游研究领域中,日本以森林浴为突破口进行研究与开发,获得了丰硕的成果,成为世界关注的焦点。本研究通过全面调查和系统整理日本森林浴基地开发建设的详细情况,对日本森林保健旅游的研究与开发成果进行系统分析,总结出了森林浴基地审核标准、森林浴基地建设、森林浴人才培养3个方面的特征和经验。在此基础上,对中国森林保健旅游的研究与开发提出相应的建议。     

近30年黑龙江省水田规模与分布变化及其对气候变化的响应

研究目的:分析黑龙江省的水田规模与分布变化,探讨气候变化对水田的影响,预测未来水田变化趋势。研究方法:文献资料法和常规数理统计方法。研究结果:近30年黑龙江省水田面积大量增加,占耕地比重逐步提高;各县市水田规模、增量和增幅差别较大,以中部地带增加最为明显,水田分布范围向东向北扩张;气温升高和热量条件改善是水田分布范围扩大的重要原因,气象灾害导致水田面积和水稻产量波动;未来水田面积将持续增加,但趋势将减缓。研究结论:黑龙江省水田规模与分布的变化与气候变化密切相关。     

基于多时相遥感数据提取水稻种植面积的研究

该文以江苏省为例,探讨MODIS时间序列数据在水稻种植信息获取中的应用,并进行精度评价.首先利用MODIS数据构建了归一化差值植被指数(NDVI)、增强型植被指数(EVI)和陆表水指数(LSWI).根据植被指数的时间序列变化特征,结合水稻的生长发育规律,确定江苏省水稻种植面积.对比统计数据,该方法提取水稻种植面积的误差为16％.同时,对环境卫星遥感影像进行监督分类,提取水稻种植区域.对比二者提取结果,面积相对误差为5％,空间一致性达到60％以上.研究表明,在平原区域利用MODIS数据监测大尺度水稻种植面积是可行的.     

Leadership in agricultural machinery circles: experimental evidence from Tajikistan

Leadership is critical for the viability of rural groups. The way in which leadership is legitimised can mediate leader and group member behaviour in the face of social dilemmas. Yet there has been scant research on leader‐follower dynamics in naturally occurring groups. Highlighting the case of agricultural machinery circles in Tajikistan, the effect of leading by example on investments to a collective good is studied in a framed field experiment. To increase realism, and contrary to standard economic experiments, this investment is a voucher allowing the group to make a real‐world machinery purchase at reduced costs. Two treatments manipulate leaders’ legitimisation. Elected leaders achieve 30 per cent higher contributions to the collective investment against a baseline version without a leader. Contributions remain, on average, relatively stable over the course of the game. The results are discussed with reference to the debate on external intervention in agricultural producer organisations.     

组织场域视角下水利水电工程BIM技术扩散的影响因素 ——基于TOE框架的分析

在梳理国内外BIM采纳与扩散相关研究的基础上,从新制度主义理论出发,提出了水利水电工程组织场域并分析了其特征;进而运用技术-组织-环境(TOE)框架和匹配理论,分别讨论了水利水电工程组织场域BIM扩散的主要影响因素,形成一个整体的理论分析框架。分析表明,水利水电工程组织场域BIM扩散的影响因素主要包括:相对优势、兼容性和复杂性等技术因素,组织沟通、资源就绪度和高层领导支持等组织因素,以及制度环境、市场环境等环境因素。     

Discouraging Rainforest Transformation: An Ex-ante Policy Impact Analysis

Despite extensive efforts made by national and international certification agencies, Indonesian smallholder farmers’ participation in palm oil certification schemes adoption remains low. A fundamental obstacle is the smallholder practice of rainforest transformation into oil palm plantation which is forbidden by the agencies. In this context, we investigate three policies that could lead to a reduction in rainforest deforestation by smallholders: price premium on certified palm oil; the provision of environmental information; contributor recognition. In order to evaluate the influence of the policies ex-ante, we conduct a social dilemma experiment involving rubber and oil palm smallholders in Jambi Province, Sumatra, Indonesia. The findings indicate that the price premium and provision of context-specific environmental information could reduce rainforest transformation. However, a statistically significant effect of contributor recognition was not found.     

基于物流场理论的物流生成及运行机理研究

随着现代物流规模的增大和物流所依托交通资源的日益社会化,物流运作形态呈现出物流源、物流迹线、物流节点、物流汇等各要素协调作用的系统效应,构成了物流场的演变形态.由于现代物流系统具备"场"的基本要素,具有明显的"场"的特征,可将场论引入物流研究领域,建立以需求力作为物流活动驱动力、以需求地作为激发场源的物流场理论.文章在物流场理论基础上,根据物流场势能、物流阻抗、物流场强等特征量的相互作用关系,推导出物流的生成机理及运行模型.研究结果表明,物流场理论能有效揭示物流活动的本质,物流生成的过程是动力、阻力相互作用的结果,在物流实践中,应尽量顺应物流场原理来设计、优化物流系统.一要安排物资在物流场势能相差最大的物流源、汇点之间流动,以保证物资价值得到最大程度的利用;二要尽量减小物流迹线中的物流阻抗,使物资流动过程损耗更小,物流活动更为高效顺畅.