农机社会化服务采纳、禀赋差异与农村经济相对贫困缓解

进入以缓解相对贫困为重点的后扶贫时代，农村经济相对贫困问题仍不容忽视。农机社会化服务作为小农户与现代农业有机衔接的桥梁，对于推进乡村振兴战略和脱贫攻坚有序衔接具有重要作用。文章讨论的核心议题是农机社会化服务采纳如何缓解农村经济相对贫困，并尝试建立了“农机社会化服务采纳——禀赋差异缩小——农村经济相对贫困缓解”的理论分析框架。为此，文章首先对农机社会化服务采纳影响农村经济相对贫困的作用机制进行了理论分析，然后利用2750份河南省农户问卷调查数据，运用Logit模型，实证检验农机社会化服务采纳对农村经济相对贫困的影响，并通过替代核心自变量和变更样本的方法进行稳健性检验，运用PSM模型和IVProbit模型以及ERM模型进行内生性讨论，最后通过中介效应模型对其作用机制进行验证。结果表明，农机社会化服务采纳对农村经济相对贫困具有显著负向影响，缓解了农村经济相对贫困。考虑内生性后，结论仍具有稳健性。进一步的机制验证发现，农机社会化服务采纳通过缩小劳动力禀赋差异和技术禀赋差异，缓解农村经济相对贫困，劳动力禀赋差异缩小和技术禀赋差异缩小的中介效应占比分别为21.22%和7.36%。可见，应将完善农机社会化服务供需体系纳入农户相对贫困治理机制考虑范畴，引导农户从传统家庭化生产转向现代社会化生产，扩大农机社会化服务采纳范围；同时完善就业服务等相关配套体系以吸纳释放的弱劳动力，促进农户收入增长，缓解农村经济相对贫困。     

老龄化与碳排放：消费效应还是生产效应？——基于2002-2017年中国省级面板数据的实证研究

人口老龄化是经济增长的一大阻碍,它对碳排放的影响是做出环境政策抉择的关键因素.以中国2002—2017年的省级面板数据为研究样本,从理论与实证两个层面分析人口老龄化与碳排放的关系及影响机制.一方面,构建包含碳排放的世代交叠模型(overlapping generations,OLG),发现老龄化主要通过消费效应和生产效应两个路径对碳排放产生影响;另一方面,从实证层面发现老龄化与碳排放之间存在倒"U"形关系,而且消费效应在人口老龄化与碳排放的关系中起到部分中介作用,生产效应的影响则不显著.     

Bitcoin price and its marginal cost of production: support for a fundamental value

This study back-tests a marginal cost of production model proposed to value the digital currency Bitcoin. Results from both conventional regression and vector autoregression (VAR) models show that the marginal cost of production plays an important role in explaining Bitcoin prices, challenging recent allegations that Bitcoins are essentially worthless. Even with markets pricing Bitcoin in the thousands of dollars each, the valuation model seems robust. The data show that a price bubble that began in the Fall of 2017 resolved itself in early 2018, converging with the marginal cost model. This suggests that while bubbles may appear in the Bitcoin market, prices will tend to this bound and not collapse to zero.     

Farm size and productivity growth in the United States Corn Belt

In recent decades, agricultural production in the U.S. has continued to shift to large-scale operations, raising concerns about the economic viability of small and midsized farms. To understand whether economies of size provided an incentive for the consolidation of production, the study estimates the total factor productivity (TFP) of five size classes of grain-producing farms in the U.S. Heartland (Corn Belt) region. Using quinquennial Agricultural Census data from 1982 to 2012 the study also compares TFP growth rates across farm sizes to gain insight into whether observed productivity differences are likely to persist. The finding of a strong positive relationship between farm size and TFP suggests that consolidation of production has contributed to recent aggregate productivity growth in the crop sector. The study estimates the extent to which sectoral productivity growth can be attributed to structural change versus other factors including technological change. The study also explores some tradeoffs associated with policies that raise the productivity of small versus large farms.     

The effect of place attachment of geographical indication agricultural products on repurchase intention

[Objective] This study aims to investigate how place attachment and the quality of experience affect consumers' intention to repurchase Geographical Indication (GI) agricultural products. [Methodology] Based on the special functional value and symbolic meaning of GI agricultural products, we constructed a five-dimensional model of place attachment for GI agricultural products consumers. Expanding on the original two-dimensional place attachment model, we introduced three connection concepts: nature, society, and emotion. We also combined this model with the quality of experience model and consumer purchase intention model to form a research model of repurchase intention for GI agricultural products. A questionnaire survey was used to collect data (n = 340), and a partial least squares structural equation model was used to test the empirical evidence. [Research results] (1) Place attachment to Geographical Indication agricultural products significantly affects the quality of experience. (2) Quality of experience significantly affects consumer trust and repurchase intention. (3) Consumer trust significantly affects repurchase intention. (4) There is a mediating effect of experience quality between place attachment and repurchase intention; there is a mediating effect of trust in the relationship between quality of experience and repurchase intention. (5) There is a chain mediating effect of “place attachment→quality of experience→consumer trust→repurchase intention” in the model.     

A REVIEW OF THE EMPIRICAL LITERATURE ON FARMER COOPERATIVES: PERFORMANCE,OWNERSHIP AND GOVERNANCE,FINANCE, AND MEMBER ATTITUDE

The empirical literature on farmer cooperatives is now fast emerging and developing in the areas of performance, ownership and governance, finance, and member attitude. We discuss 56 peer‐reviewed publications to illustrate the main findings and conclusions while outlining challenges and opportunities for future research. Generally, cooperative membership is found to positively impact price, yield, input adoption, income, and other indicators of member performance, yet there is growing evidence of an uneven distribution of benefits for small and large producers. In terms of structure, evidence of a causal relationship of ownership and governance to performance has been elusive, yet there are now many findings of inherent equity and long‐term debt constraints, often in the context of consolidation to drive scale and scope economies. Further inefficiency is observed to be driven by increased heterogeneity in member attitudes and objectives, in particular in terms of commitment and participation. Thus, overall, empirical work portrays farmer cooperatives as flawed and complex business organizations which nonetheless have a strong positive impact on its members. While applied research may progress in various directions, a general improvement in empirical methodologies is needed to allow robust analysis of mixed objectives in dynamic environments.     

Are China’s regional agricultural productivities converging: How and why?

This article tests the hypotheses of convergence to a single level of total factor productivity (TFP), and a steady state of TFP growth rate in China’s agricultural sector. Based on multilateral TFP estimates we found that China’s agricultural sector has rebounded in recent years from a slower TFP growth in the 2005–2007 period. While convergence test results confirm a “catch-up” effect that provinces with lower TFP levels tend to grow faster than others, estimated rates of β convergence are conditional on how we capture the heterogeneity effect across regions. The rates of β convergence range from 0.016 to 0.039 under different model specifications. Estimates show that higher growth rates of educational attainment, R&D, and intermediate goods density (per unit of labor) can enhance TFP growth. Unfortunately, there is no evidence of an overall σ convergence, indicating that TFP levels are not converging except in the South region. It implies that to catch up with leading provinces, it would require extra efforts for those lagging behind by increasing their region-specific research investment, promoting rural educational attainment, and enhancing embodied technical change.     

Methodological Advances in DEA: A survey and an application for the Dutch electricity sector

We survey the methodological advances in DEA over the last 25 years and discuss the necessary conditions for a sound empirical application. We hope this survey will contribute to the further dissemination of DEA, the knowledge of its relative strengths and weaknesses, and the tools currently available for exploiting its full potential. Our main points are illustrated by the case of the DEA study used by the regulatory office of the Dutch electricity sector (Dienst Toezicht Elektriciteitswet; Dte) for setting price caps.     

Nonparametric Dynamic Production Analysis and the Theory of Cost

While the dynamic theory of production provides little insight towards identifying a specific functional form for the firm's technology, dynamic production analysis has been explored traditionally in a parametric framework. A nonparametric dynamic dual cost approach to production analysis is developed in this article. Recovering technological information from intertemporal cost minimizing behavior is possible without imposing a parametric functional form on the firm's technology. Nonparametric tests to analyze the structure of a dynamic technology are presented from a dynamic cost minimizing perspective. The empirical implementation of these tests is illustrated for a balanced panel data set of Pennsylvania dairy operators during the time period 1986–1992.     

一类有向网络的容量扩张问题研究

将网络容量定义为最大流的流量。针对网络容量的三种扩张方式：点扩张、弧扩张、点扩张和弧扩张相结合,分别建立数学模型,提供算法;在分开讨论的基础上,还提出了统一的容量扩张模型;最后提供了一个具体算例。