水足迹视角下我国农业水土资源匹配及农业经济增长——以长江经济带为例

［目的］水土资源是重要的农业生产资源,农业水土资源的合理匹配有利于充分利用区域现有资源优势,从而对区域农业经济增长产生影响。［方法］文章从水足迹视角出发,以长江经济带11个省市为研究区域,运用水土资源匹配系数法深入分析其不同区域农业水土资源匹配情况,并进一步运用空间计量模型探究区域农业水土资源匹配度对农业经济增长的影响。［结果］我国长江经济带整体农业水土资源匹配度为0426万m3/hm2,低于全国水平,且整体处于缓慢下降趋势,匹配程度在逐年变差;农业水土资源当量系数为0709,属于缺土地区;农业经济增长的Moran′s I指数显著为正,即存在显著空间关联,但2008年以后关联性有减弱迹象; 我国长江经济带地区农业水土资源匹配度对农业经济增长的促进作用不明显。［结论］其区域农业经济增长与农业水土资源空间匹配状况之间存在明显错位现象,即实际农业经济增长较快地区农业水土资源匹配度较差,而农业经济增长较慢地区农业水土资源匹配度较好。     

无人机载框幅式高光谱影像的波段配准研究

[目的]高光谱成像技术在卫星遥感平台上由于飞行高度与技术限制等原因无法满足当前对于智慧农业与精准农业的需求,无人机平台的出现可以有效地弥补这一问题,给精细化、定量化研究农田信息提供数据支持。受平台稳定性,荷载能力等因素的制约,传统的推扫式高光谱成像仪不适用于无人机平台,而框幅式成像仪的应用前景较为广泛。但此类成像仪由于成像原理等因素的影响,获取的波段图像间存在姿态与位置差异,无法直接投入到后期应用中,在投入使用前需要进行波段配准。[方法]结合传统基于特征点的配准方法针对波段配准展开研究,对图像间灰度与位置差异对配准精度的影响进行了深入分析,针对传统的研究方法在匹配灰度存在非线性变换的图像上不足等问题,设计了两组匹配策略实验,分别为拍摄顺序的配准实验对比与波段顺序的配准实验对比。[结果]通过实验对比证明在引入拍摄顺序的变换基准的匹配策略下可以自动且稳定完成配准任务,此方法下配准精度可以达到亚像元级。[结论]文章所提方法兼顾了波段顺序与拍摄顺序,匹配结果可达亚像元级,是较优的匹配策略。     

基于AHP的农业节水技术公司化服务模式绩效评价研究

[目的]农业节水技术公司化服务模式,以公司化为载体采用技术有偿服务的方式进行整建制推进高效节水的发展,能够有效地优化配置资源,减少成本,增加生产效益。随着农业节水技术公司化服务模式应用的增加,人们对其绩效越发关注,但截至目前,仍缺乏一套科学可行的绩效评价指标体系,无法全面的对其进行评价。[方法]以平衡计分卡4个维度为基础,从服务业绩、服务对象、内部运行机制和服务主体的发展4个层面构建一套科学合理的绩效评价指标体系,运用AHP(层次分析法)进行指标权重确定,采用功效系数法对指标进行标准化处理,计算指标分值,并利用所构建的指标体系和评价方法对鄯善县农业节水技术公司化服务模式进行实证分析。[结果]农业节水技术公司化服务模式能够有效地解决节水工程后期运行管护力量薄弱,设备损坏无法及时得到维修等一系列问题,从而达到节水、增产、增收的目的,委托单位和农户对服务模式的服务质量比较满意。[结论]文章基于平衡积分卡建立了一套切实可行的评价方法,为农业节水技术公司化服务模式绩效评价提供了一种范式,丰富了农业高效用水管理模式理论,有利于为利益相关者提供借鉴与参考,具有一定的现实意义。     

农民合作社减贫、增收效应与异质性分析基于中国西部贫困地区农户调研数据

目的 在脱贫攻坚视域中,农民合作社作为产业扶贫的重要载体,为乡村经济和社会发展提供动力,是农村地区反贫困合意、有效的组织化形态,对农民合作社减贫问题进行研究,具有重要的理论价值和现实意义。方法 文章利用2018年云南、贵州、陕西和甘肃4省7县1 393户农户的微观调研数据,采用分位数回归和倾向得分匹配法对农户参加农民合作社的增收效应进行了实证检验。结果 农民合作社可以有效改善农户家庭收入水平,参加农民合作社可以使农户家庭总收入平均提高38.04%;农民合作社对中高收入水平农户、非贫困农户、低学历农户的增收促进作用更为明显;另外,户主受教育年限、是否建档立卡、土地面积、村里面是否有农民合作社、人情往来支出对数、政府补贴津贴对数、是否参加专业培训等7个因素均提高了农户参加农民合作社的意愿,而户主年龄、学生数量、是否有外出务工人员等3个因素会降低农户参加农民合作社的意愿。结论 据此,应继续培育和发展农民合作社,提升农户参与农民合作社的意愿,强化农民合作社与贫困农户的利益联结,注重扶贫资源对于贫困农户获得的便利性。     

Endemic-epidemic models with discrete-time serial interval distributions for infectious disease prediction

Multivariate count time series models are an important tool for analyzing and predicting the spread of infectious disease. We consider the endemic-epidemic framework, a class of autoregressive models for infectious disease surveillance counts, and replace the default autoregression on counts from the previous time period with more flexible weighting schemes inspired by discrete-time serial interval distributions. We employ three different parametric formulations, each with an additional unknown weighting parameter estimated via a profile likelihood approach, and compare them to an unrestricted nonparametric approach. The new methods are illustrated in a univariate analysis of dengue fever incidence in San Juan, Puerto Rico, and a spatiotemporal study of viral gastroenteritis in the 12 districts of Berlin. We assess the predictive performance of the suggested models and several reference models at various forecast horizons. In both applications, the performance of the endemic-epidemic models is considerably improved by the proposed weighting schemes.     

Remittances and household expenditure behaviour: Evidence from Senegal1

We use different econometric techniques, from propensity score matching to multinomial treatment methods, to assess the impact of internal and external remittances on several household budget shares in Senegal. When only considering the average impact of remittances on the household expenditure behaviour, we find an overall productive use of remittances. However, the impact of remittances disappears when the marginal spending behaviour is considered, i.e., households do not show a different consumption pattern with respect to their remittance status. The marginal spending behaviour therefore suggests that, in the decision on how to allocate expenditure, remittances are treated just as any other source of income.     

Economic migration and business cycles in a small open economy with matching frictions

With the free movement of labour in Europe, economic migration has become an important determinant of labour supply. Cyclical migration exceeds one percent of the population in many countries and affects (un)employment and wage setting. The main contribution of this paper is that it models migration as an endogenous decision in a search-and-matching framework, where labour market institutions play an important role. It shows that, contrary to typical beliefs, migration can amplify business cycles. After a positive shock to the economy, immigration increases the labour force and initially unemployment. The latter reduces a worker's outside option in wage negotiations, resulting in a lower wage increase than when there is no migration. With cheaper labour firms post more job vacancies, which increases the probability that unemployed workers find jobs and attracts new workers to immigrate. Attenuated response of wages and the stronger response of employment to shocks result in a flatter Phillips curve.     

Comparative statics for size-dependent discounts in matching markets

We prove a natural comparative static for many-to-many matching markets in which agents’ choice functions exhibit size-dependent discounts: reducing the extent to which some agent discounts additional partners leads to improved outcomes for the agents on the other side of the market, and worsened outcomes for the agents on the same side of the market. Our argument draws upon recently developed methods bringing tools from choice theory into matching.     

The impact of protected areas on the rural households’ incomes in Ethiopia

Protected areas are cornerstones for biodiversity conservation, yet they can be controversial because of their potential impact on the livelihoods of local people due to restrictions on agricultural land use and the extractive use of natural resources. This study evaluates the impact of PAs on households’ livelihoods, as measured by total household income (THI) and livestock income (LI). We use a survey and a quasi-experimental design to gather socioeconomic and biophysical data from households living within, adjacent to and outside three national parks (NPs) in Ethiopia and employ matching methods to isolate the impact of NPs. Our findings suggest that there is no evidence that the establishment of NPs adversely affects local livelihoods. Instead, we find that households within and in adjacent areas to NPs have higher incomes compared to those living outside. Understanding the heterogeneity of the effect of NPs on local livelihoods can help in designing well-targeted policy interventions that improve conservation goals while also addressing livelihood concerns of resource-dependent local communities.     

Does Cross-Listing Really Enhance Market Efficiency for Stocks Listed in the Home Market? The Perspective of Noise Trading in the Chinese Stock Market

The investor recognition hypothesis and the bonding hypothesis, which help us understand the market quality of stocks that are cross-listed on different stock markets, imply improved market efficiency after cross-listing because of increased investor participation. However, the noise trading of inexperienced investors in the Chinese stock market negatively affects market efficiency. By employing propensity score matching and multivariate regression analysis, we show that the increased individual investor participation actually lowers market efficiency in their home market after cross-listing. This effect is more evident for stocks that were either listed first on the Chinese stock market or listed on the Chinese stock market and the Hong Kong stock exchange (SEHK) on the same date than for stocks that were listed first on the SEHK.