Food-water security and virtual water trade in the Middle East and North Africa

The purpose of this study is to analyze the political economy of food-water security in the water-scarce Middle East and North Africa region. The study deploys the lens of virtual water trade to determine how the region's economies have met their rising food-water requirements over the past three decades. It is shown that the region's water and food security currently depend to a considerable extent on water from outside the region, ‘embedded’ in food imports and accessed through trade. The analysis includes blue (surface and groundwater) and green water resources.     

Establishing spatial trends in water chemistry and stable isotopes (δ15N and δ13C) in the Elwha River prior to dam removal and salmon recolonization

Two high‐head dams on the Elwha River in Washington State (USA) have changed the migratory patterns of resident and anadromous fish, limiting Pacific salmon to the lower 7.9 km of a river that historically supported large Pacific salmon runs. To document the effects of the dams prior to their removal, we measured carbon and nitrogen stable isotope ratios of primary producers, benthic macroinvertebrates, and fish, and water chemistry above, between and below the dams. We found that δ¹⁵N was significantly higher in fish, stoneflies, black flies, periphyton and macroalgae where salmon still have access. Fish and chloroperlid stoneflies were enriched in δ¹³C, but the values were more variable than in δ¹⁵N. For some taxa, there were also differences between the two river sections that lack salmon, suggesting that factors other than marine‐derived nutrients are structuring longitudinal isotopic profiles. Consistent with trophic theory, macroalgae had the lowest δ¹⁵N, followed by periphyton, macroinvertebrates and fish, with a range of 6.9, 6.2 and 7.7‰ below, between, and above the dams, respectively. Water chemistry analyses confirmed earlier reports that the river is oligotrophic. Phosphorous levels in the Elwha were lower than those found in other regional rivers, with significant differences among regulated, unregulated and reference sections. The removal of these dams, among the largest of such projects ever attempted, is expected to facilitate the return of salmon and their marine‐derived nutrients (MDN) throughout the watershed, possibly altering the food web structure, nutrient levels and stable isotope values that we documented. Published in 2010 by John Wiley & Sons, Ltd.     

我国进口食品安全监管存在的问题及对策建议

食品是人类最直接、最重要的消费品。食品安全状况是衡量一个国家经济发展水平和人民生活质量的重要指标。随着我国进口食品的数量和品种逐年增加,我国进口食品安全问题也日益突出。根据国家质检总局统计数据显示:2008年查获的不合格的食品和化妆品共3162批次,2009年共1591批次,2010年共1645批次,2010年前两个月共252批次。不断发生的进口食品安全问题凸显了我国食品安全监管法律制度的漏洞。为确保我国进口食品安全和保护我国消费者食品安全消费需求,完善我国进口食品安全监管法律制度,构建科学合理的进口食品安全监管体系是当务之急。     

Food security problems in sub-Saharan Africa: Operations Research as a tool of analysis

For many years, the author has been involved in teaching and research in the use of Operations Research as a tool of analysis to study food security problems in sub‐Saharan Africa, in particular, grass root problems of poor farmers. The paper presents an introduction to the way Operations Research methods have been applied in case studies and research projects, and discusses in retrospect the author's views on the strengths and limitations of the application of Operations Research. The paper has in particular been written for people who are not familiar with applications of Operations Research in agriculture, and are interested to learn about its potential usefulness in practice. The retrospective part is largely based on food security studies in e.g. Tanzania, Burkina Faso, Bénin, Togo and Eritrea and on participation in several interdisciplinary research programmes in Africa.     

基于手机短信的订餐系统设计与开发

手机的普及为移动电子商务的开展创造了条件.介绍了利用手机开展移动电子商务的3种主要模式,结合具体应用提出了一种构建在手机短信平台上的移动订餐系统.该系统利用J2ME和XML技术实现了订餐短信的自动生成,利用GSMModem实现了移动短信平台与计算机系统的集成,同时实现了订餐短信的自动分发路由.与其它基于手机短信的商业应用不同,该系统不依赖于通信运营商的端口,相对自主.短信订餐相对传统订餐方式有明显优势.     

新的仿生算法:蟑螂算法

通过模拟蟑螂的觅食行为,提出蟑螂算法(Cockroach Swarm Optimization,CSO)。算法充分利用了蟑螂社会的平等特性和群体智慧。食物再分配、回巢等策略的使用使算法具有较强的全局搜索和局部搜索能力。以TSP问题为例对算法进行仿真测试,实验证明算法有效且优于存在的离散粒子群算法(Discrete Particle Swarm Optimization,PSO)。     

Optimal markdown policy of perishable food under the consumer price fairness perception

Markdown policies are widely used by retailers to sell perishable food. Consumers purchase food at different prices during different sales periods. Some consumers may compare their experience with others who purchase the same items. Price unfairness or inequity is perceived when different prices are quoted without reasonable explanations. This study develops an optimal markdown model for perishable food pricing to optimise the food retailer revenue and enable a maximum aggregated consumer utility considering individuals’ price fairness perception. The model serves as the first step in evaluating trade-offs between food retailer revenue and consumer utility. In addition, it enables consumer utility to be depicted through perceived price fairness by including the effects of food perishability and scarcity. Another innovative feature is the equalisation of the consumer average aggregated utility during different sales periods as a condition of intertemporal price fairness perception. The proposed model is compared with two benchmark models to justify the effectiveness and advantages in the example. Finally, a sensitive analysis based on the food deterioration rate, consumer food desire rate and consumer average reservation price is conducted to justify the manner in which these factors influence the optimal pricing policy, and managerial insights are suggested for food retailers.     

气相色谱法测定食品包装纸中饱和烃矿物油迁移量

本文运用气相色谱技术建立了食品包装纸中饱和烃矿物油迁移量检测方法.本方法检出限和定量限分别为2.28mg/L和6.84mg/L,采用低、中、高3个浓度水平对样品进行加标回收试验,加标回收率为95.46%~106.38%,相对标准偏差<4.0%.优质原生纸样品食品模拟物未检出矿物油,而回收食品包装纸中均存在不同矿物油迁移量,尤其是含有油墨、石蜡和粘合剂等的回收纸.     

聚氯乙烯食品接触材料中稀土热稳定剂检测方法探讨

广大消费者越来越关注食品安全问题.聚氯乙烯食品接触材料通常情况下不稳定,需加入热稳定剂使其不易见热分解,而这些热稳定剂有可能迁移入食品中,致使使用者出现毒物反应.本文依据检验工作实践,对PVC食品接触材料中稀土热稳定剂检验方法进行了探讨,并提出了需注意的问题.