Food values and heterogeneous consumer responses to nanotechnology

Agricultural applications of nanotechnology are at a relatively early stage and little is known about consumer responses to the technology. Canadian consumer responses to food nanotechnology are examined through the lens of the Food Value Scale. Data from a survey of Canadian consumers are used to evaluate the relative importance of eleven food values to food purchase decisions. We find that taste, safety, nutrition, and price are among the most important food values to Canadians, however, consumers exhibit considerable heterogeneity with respect to the priority placed on these values. A discrete choice experiment (DCE) explores the effect of food values on choice behavior. The DCE is positioned as a sliced apple product with non-browning and antioxidant-enhanced features introduced through the use of nanocoating or a conventional coating method. Random parameters logit (RPL) and latent class models (LCM) confirm the existence of significant preference heterogeneity. The LCM identifies three classes of consumers: “supporters,” “doubters,” and “opponents” who differ in their reaction to nanotechnology and in the relative importance placed on food values such as naturalness, novelty, and convenience. The analysis shows that food values provide additional insights into consumers’ food choices and their attitudes toward novel food technologies.     

中国水资源利用秩序评价

水资源利用秩序反映了水资源供给侧效率和需求侧公平的程度。采用秩序模型对我国30个省级行政区2008—2017年的水资源利用状态进行测度,通过测量高低收入人群收入差距的变动状况度量公平程度,使用数据包络分析法将全要素生产率的增长进行分解,从而度量其效率发挥状况,将二者综合,计算水资源总秩序水平。研究结果表明:我国大多数省级行政区水资源利用纵向秩序较好、横向秩序较差,因此应采取措施,以保障水资源利用秩序保持在较高且比较稳定的水平上。     

中国农村减贫成效测度、分解及影响因素研究——基于分布动态学框架的CFPS数据分析

测算农村减贫成效并考察减贫成效的影响因素对我国打赢"脱贫攻坚战"具有重要的现实意义。本文基于覆盖我国东、中、西和东北四大地区的CFPS调查数据,在Quah(1997)的分布动态学(Distribution dynamics)基础上构建了完整的减贫成效分析框架。首先测算出各地区农村家庭贫困内部状态的Markov转移概率矩阵,并在此基础上构建了可分解的绝对、相对减贫指数,以综合考察各地区的农村减贫成效,随后本文通过首次构造的"条件Markov模型"进一步考察了减贫成效的影响因素。研究结果发现:(1)样本考察期内,我国各地区的农村贫困状况随着时间的积累逐渐变好,贫困发生率均有所下降;(2)减贫过程中仍存在着脱贫又返贫的现象,农村家庭的深度贫困固化问题比轻度贫困问题更加严重,意味着扶贫开发工作正式进入攻坚时期,扶贫难度加大;(3)家庭成年成员特征、家庭特征以及收入类型对农村减贫成效的影响显著性情况存在着时段和区域的异质性。其中,家庭成年成员受教育水平、家庭中是否有成员从事有薪酬的农业劳动、工资性和营业性收入对家庭的贫困状态变动具有更显著的影响。基于此,政府应贯彻落实精准扶贫,将扶贫重点放在中西部地区和处于深度贫困的家庭,另外应再调整和倾斜扶贫资源与扶贫政策,将提高农民受教育水平、增加非农业就业机会作为主要减贫途径,将促进农村工资性和营业性收入增长作为主要的政策倾斜方向。     

How forestland size affects household profits from timber harvests: A case-study in China’s Southern collective forest area

To improve the economies of scale in forest management and reduce the fragmentation of forestland, the Chinese central government has implemented a collective forest tenure supplementary reform since 2008. This has included a series of policies for motivating transfer of forestlands use rights among households in the country’s Southern Collective Forest Area (SCFA). However, to date there is little evidence that large-scale forest owners can earn more profits from timber harvests than small-scale forest owners in the SCFA. Using data collected from household surveys in the three of the SCFA’s provinces in 2016, this paper examines the return to scale of forestland ownership for timber harvests in this region, and how the scale of forestland ownership affects households’ profits from timber harvests. The results show a constant return to scale in timber harvests in the case provinces in China’s SCFA, that forestland area makes the most important contribution to the output of timber harvests, and that fragmentation of forestland results in lower profits from timber harvests. It appears that a moderate scale of forestland ownership should be identified for increasing the profits from timber harvests. With the rapid urbanization throughout China, an increase in off-farm employment among rural household members has a negative impact on timber harvests in the region. We argue that policymakers should realize the importance of encouraging the forestland transfers and improve the concentration of forestlands in the next stage of forest tenure rights reform in China’s SCFA.     

苹果种植适度规模经营研究*——以陕西省白水县为例

［目的］分析苹果种植户经济效益的影响因素，研究适合苹果种植的农地规模，提高白水县果农苹果种植的经济效益，探索苹果产业可持续发展经营模式，丰富以果蔬为主的集约型经济作物适度规模经营研究范围。［方法］采用实地调研法，对陕西省白水县230户苹果种植户进行问卷调查，从收益最大化角度，运用柯布道格拉斯生产函数对苹果生产的投入产出进行经济分析，构建收益最大化模型，测算白水县苹果种植的最适规模，分析苹果产量的影响因素，探讨劳动力投入、资本投入、有效面积和果农参加技术培训对苹果产出的影响和贡献程度，并用钱克明等对农地的适度经营规模定义进行结果验证，最后提出合理的政策建议。［结果］经过分析，在同等技术条件下，劳动力投入、资本投入、有效种植面积、果农参加技术培训的次数对苹果的产出具有显著影响。以农户收益最大化模型测算的劳均经营规模面积在0363~0447hm2（544~670亩）的可视为适度规模，根据钱克明等的适度经营规模目标值的计算，其函数解为550，在适度规模范围之内。即户均农地适度经营规模0751~0966hm2（1127~1449亩）。目前白水县苹果生产处于规模报酬递减阶段，农资市场环境和劳动力投入方面仍然存在短板。［结论］建议扩大白水县户均苹果种植面积，提升土地经营效益，从而增加果农收入，支持农业新型经营主体发展，创新发展模式； 建立新型职业农民培育体系，促进苹果种植户剩余劳动力转移，提高农民非农收入； 从法律上规范农村地区农资市场环境； 规范农户绿色生产经营行为，提高化肥的使用效率和开发新的高效肥料； 政府引导农地的适度规模集中，整合资源进行规模化、现代化的经营。     

我国蛋鸡养殖环境全要素生产率测度及省域比较分析

［目的］蛋鸡养殖场规模化养殖与生态环境保护协调发展问题是蛋鸡养殖业可持续发展过程中面临的关键性问题，测度我国大、中、小3种规模下不同省份蛋鸡养殖场的环境全要素生产率，并从时间、地区两个维度对蛋鸡养殖场的环境全要素生产率进行比较。［方法］利用2004—2016年不同养殖规模蛋鸡养殖场的投入和产出数据，文章基于SBM函数的Malmquist Luengerber（ML）指数方法，对蛋鸡养殖场环境全要素生产率进行分解，将其分解为技术进步指数、效率改进指数。［结果］（1）蛋鸡养殖场环境全要素生产率整体呈现下降趋势，同时与蛋鸡养殖规模呈反比，蛋鸡养殖场规模越大，蛋鸡养殖环境生产率越小。（2）蛋鸡养殖场效率存在效率改善，但养殖技术进步率相对较低，尤其是对小规模养殖场而言，改善空间更明显； （3）蛋鸡养殖环境全要素生产率区域差异较为明显，整体来看，蛋鸡养殖主产区环境全要素生产率高于非主产区。［结论］加强蛋鸡产业科技创新水平以及公共服务设施的投入，提高养殖户的废弃物无害化处理能力，推行蛋鸡养殖的规模化和标准化发展，进一步改善养殖效率，以促进蛋鸡养殖规模化和生态环境保护协调发展。     

Construction of a service quality scale for the online food delivery industry

The main purpose of this study is based on qualitative and quantitative research procedures, and integrates the key service factors for the online food delivery (OFD) industry extracted by Internet Big Data Analytics (IBDA) to construct a OFD service quality scale (OFD-SERV). This study takes OFD customers in Taipei City as the objects. The results show that 20 key service factors for the OFD industry are extracted through IBDA. The OFD-SERV scale contains six dimensions including reliability, maintenance of meal quality and hygiene, assurance, security, system operation and traceability, a total of 28 items. The results from the structural equation modeling showed that the reliability, assurance and system operation have a positive impact on customer satisfaction. Finally, the findings provide knowledge and inspiration for the current OFD, and enable OFD operators and future researchers to more accurately identify the deficiency of service quality.     

社会互动对规模养殖户环保饲料支付意愿的影响研究*——基于改进的目标导向理论模型分析框架

［目的］通过引入社会互动变量改进目标导向行为理论框架，探讨生猪规模养殖户对环保饲料的支付意愿及其影响因素，为完善畜禽养殖污染防治政策提供参考借鉴。［方法］以湖北省生猪规模养殖户为研究对象，应用Heckman两阶段模型，研究规模养殖户对环保饲料的支付意愿。［结果］大多数规模养殖户（8134%）愿意采用环保饲料，且平均意愿支付水平为每头生猪饲料成本的669%（4680元/头）。社会互动中的干群互动、同行互动均能显著提升规模养殖户对环保饲料的支付意愿，但同时同行互动不利于其意愿支付水平的提升。进一步的异质性分析表明，在环保饲料支付意愿决策上，社会互动较少的规模养殖户更容易受到制度规范的约束，而社会互动较多的规模养殖户则更易受到感知养殖热情的影响。［结论］政府部门应加大生态环保宣传力度，并借助多种方式推动规模养殖户进行社会互动； 同时可依据社会互动程度的不同，分别制定相应措施以促进规模养殖户对环保饲料支付意愿的提升。     

Comparison of dimension reduction methods for DEA under big data via Monte Carlo simulation

Data with large dimensions will bring various problems to the application of data envelopment analysis (DEA). In this study, we focus on a “big data” problem related to the considerably large dimensions of the input-output data. The four most widely used approaches to guide dimension reduction in DEA are compared via Monte Carlo simulation, including principal component analysis (PCA-DEA), which is based on the idea of aggregating input and output, efficiency contribution measurement (ECM), average efficiency measure (AEC), and regression-based detection (RB), which is based on the idea of variable selection. We compare the performance of these methods under different scenarios and a brand-new comparison benchmark for the simulation test. In addition, we discuss the effect of initial variable selection in RB for the first time. Based on the results, we offer guidelines that are more reliable on how to choose an appropriate method.     

一种利用均匀圆阵对称特性的近场源酉变换估计算法

针对现有均匀圆阵的近场源三维参数估计算法运算量大的缺点，提出了一种基于均匀圆阵对称特性的近场源酉变换估计算法。该算法利用均匀圆阵对称特性将阵列导向矢量进行酉变换和对角化分离处理，消除距离参数，把三维搜索问题化简为二维搜索问题，同时把复值方向矢量转化为实值方向矢量。计算机仿真结果显示,所提算法估计性能优于相关序列降维估计方法，与三维多重信号分类算法性能相当，且通过矩阵分离降维和实值化处理，减少了运算量，有利于工程实时处理。