Are multiple labels on food products beneficial or simply ignored?

This study examines consumer preferences and willingness to pay (WTP) for organic wheat products exhibiting single labels, as well as multiple labels, including organic. The additional labels considered are related to the organic label (non-genetically modified organism [non-GMO]) or perceived as health-promoting (gluten-free, low-carb, sugar-free). Study data were collected using a consumer survey conducted online in 2017 across 16 U.S. western states and analyzed using random parameter logit models. Findings show that organic-labeled wheat products with additional claims were valued equally or less than the organic only version. Overall, consumer higher objective and subjective knowledge of organic standards, as well as preferences for gluten-free products, increased their WTP for organic wheat products. Consumers unfamiliar with organic standards valued the non-GMO label over the organic label. Additionally, consumer WTP for health-related claims on hedonistic products was low or even negative. Hence, multiple labels on organic products generally provide no additional consumer benefit and are likely ignored. Study findings suggest that using the claim that most distinguishes the product, or is most salient, may improve product pricing. Also, non-GMO certification rather than organic certification should be considered for some markets. Finally, consumers with preferences for gluten-free products represent a potential market for organic wheat products.     

我国小麦生产、消费和贸易的现状分析

[目的]小麦是在全球范围内广泛种植的一种非常重要的粮食作物,在三大粮食作物中保持着收获面积第一的地位。中国既是世界上最大的小麦生产、消费国,也是世界小麦贸易大国。全面多角度地分析我国小麦的供需现状,找出小麦产业发展面临的难题,提供科学合理政策建议,对于优化小麦生产和促进小麦贸易都具有积极意义。[方法]利用2007-2016年的统计数据,采用对比分析法对近年来我国小麦的生产、消费和进出口贸易情况进行研究,通过国际竞争力指标分析法测算了10年间我国小麦国际贸易竞争力水平,并与小麦主要出口国进行比较。[结果](1)我国小麦总体生产能力稳步提升,2016年小麦产量已达到1.29亿t,小麦的生产区域主要集中于河南、山东等省份,大部分省份仅少量种植小麦,小麦的成本收益率相对较低,净利润不断走低。(2)小麦消费量平稳增加,我国小麦的消费量达到1.16亿t,口粮消费占比80%,消费量较大的省份也多分布在小麦主产区,中部地区省份消费缺口相对较大。(3)小麦的贸易量趋向合理,进口量达453万t,我国小麦的供需总体上保持了平衡,但小麦国际贸易逆差较大,小麦的国际竞争力较弱,小麦进口来源过于集中在加拿大、美国等小麦生产大国的状况并未改善,好在哈萨克斯坦和俄罗斯等新兴小麦大国的兴起为我国小麦的多元化贸易提供了契机。[结论]我国要坚持小麦生产以我为主的战略,做好政府服务和市场导向的有机结合,增加农业投入促进小麦高效优质生产,加大科技进步对小麦生产的贡献,合理利用国际市场等措施来保障小麦充分供给,确保国家粮食安全。     

自动化立体仓库监控系统典型结构模式分析

论文介绍了自动化立体仓库监控系统的典型结构模式,并分析了集中控制式、功能分散式、分层分布式的结构特点;并通过与集中控制式比较,重点分析了分层分布式自动化立体仓库监控系统结构的优缺点;对自动化立体仓库监控系统结构的发展趋势进行了概述。     

麦胚的综合开发利用研究

从麦胚蛋白、麦胚活性肽、麦胚油、谷胱甘肽、维生素E、麦胚凝集素、麦胚黄酮和2，6-二甲氧基对苯醌等成分的提取及开发利用前景进行论述。     

活接式电焊训练夹具在培训及生产中的作用

活接式电焊训练夹具是制做用于采油厂电焊工累积带水焊接经验,提高带水焊接技术的一种训练器具。在队上训练即可获得在油水井管线流程施工现场的操作效果,具有一定的实际意义。     

中国小麦生产的时空演变特征及其影响因素分析

［目的］分析小麦生产的时空演变特征及成因，可以掌握小麦生产的时空分布规律，从而更加合理地配置农业资源，优化农业生产的空间布局，推动农业供给侧结构性改革，保障小麦产业的稳定发展。［方法］首先利用基尼系数、产业集中度指数等指标对1978—2016年我国小麦生产的时空演变特征进行分析，然后建立空间面板杜宾模型定量研究我国小麦生产布局变化的驱动因素。［结果］］改革开放以来，我国小麦生产逐渐向优势区域集中，集中程度不断提高，呈现出由东向西、由南向北的空间移动趋势，并且小麦生产表现出较强的空间依赖性。实证研究结果表明，农村劳动力的非农就业机会对小麦生产规模具有显著的负向影响，小麦生产的比较效益、农业机械化发展水平和小麦的平均产量对小麦生产规模具有显著的正向影响，此外小麦生产的比较效益和农业机械化发展水平还对邻近地区的小麦生产规模具有正向溢出效应。［结论］为保证我国小麦供给的安全，应进一步提高小麦的单产水平，大力提升小麦耕、种、收等环节的机械化水平，并不断提高小麦种植的比较效益。     

旅游相关企业松散型纵向一体化战略联盟研究

中国旅游产业发展水平之所以不高，深层次的原因是旅游产业链中存在着严重的纵向外部性问题，借助演化博弈思想对旅游产业链中经济主体的决策行为进行深入分析后，认为纵向一体化战略联盟能有效提升旅游产业链和相关主体利益，在传统的纵向一体化联盟基础上提出了一种界于市场和企业，且又不同于完全一体化的“混合”组织形式——松散型纵向一体化战略联盟，并初步描绘了这一联盟模式的构建过程。     

结合植被指数与作物高度反演冬小麦叶面积指数

[目的]叶面积指数LAI(Leaf Area Index)是反映作物长势的关键参数之一。目前,基于无人机影像进行LAI反演多注重影像光谱信息的应用,但是由于高分影像存在强烈的光谱异质性以及无法区分高密闭度植被垂直方向枝叶的光谱特征等不足,在反演作物LAI时,需要探讨作物高度等结构参数对LAI反演的影响。[方法]文章以冬小麦为例,将无人机影像的光谱信息与点云数据相结合,共同构建LAI反演模型,并与单利用光谱信息的一元线性LAI回归模型进行对比,探讨作物高度信息对LAI反演精度的影响。[结果](1)无人机影像获取的点云数据能有效反演作物高度,其决定系数R~2=0.61,均方根误差RMSE=0.02;(2)基于作物高度和植被指数Ⅵ(Vegetation Index)反演LAI的二元模型(Adjust R~2=0.38,Adjust RMSE=0.55)优于单用植被指数反演LAI的一元模型(Adjust R~2=0.29,Adjust RMSE=0.59),[结论]研究表明作物高度和光谱信息结合的反演模型能够提高作物LAI的反演精度,同时表明作物高度因子在LAI反演中具有重要的应用价值。     

Wheat stocks and the cointegration of wheat prices

We examine the effect of wheat stocks on the relationship between port and inland wheat prices in western Canada after the dissolution of the Canadian Wheat Board in 2012. Standard statistical tests find no evidence that the port price is cointegrated with inland prices. We argue that large harvests in 2013–2014 and 2014–2015 are responsible for this lack of cointegration. A simple theoretical model demonstrates how wheat stocks drive a wedge between inland and port prices. After including wheat stocks in the cointegrating vector, we find the expected cointegrating relationships between the port and inland prices. Using an error correction model, we show that a 10% increase in the wheat stocks reduces producer prices in Alberta and Manitoba by 6% and 4%, respectively. We conclude by discussing policy options for reducing the size of wheat stocks on the prairies.     

Financialization and commodity prices – an empirical analysis for coffee,cotton, wheat and oil

Commodity prices have crucial implications for developing countries. The question whether the financialization of commodity derivative markets has contributed to high and volatile commodity prices has been controversially debated. Building on limitations in the empirical literature, we estimate a multivariate Vector Autoregressive (VAR) model to assess the effect of different groups of financial investors (index investors and money managers) as well as fundamental and macroeconomic variables on the prices of coffee, cotton, wheat and oil. We find that, in contrast to index investors, money managers’ net long positions have a large statistically significant effect on commodity prices. This calls for policy interventions as commodity derivative markets may cease to perform their fundamental developmental roles.