Getting Real About Food Prices

The 2008 spike in world grain prices is widely recognised to have had serious impacts on food security and poverty, but these high grain prices are commonly described as low in historical terms – an inconsistency resulting from the use of advanced‐ and global‐economy price indices in calculating real prices. This ignores the high share of food in poor people's expenditures and the indirect effects of income growth on expenditure patterns of rich consumers. Poor consumers have not experienced the same falls in real food prices and are more vulnerable to price shocks. Different price indices must be developed to take account of differences between consumer groups.     

Usability Study of a Distance Continuing Education Website for Human Service Professionals

ABSTRACT

A usability test of a distance continuing education website for human service professionals is discussed. The website's purpose was to help meet the continuing education needs of human service professionals in a largely rural Midwestern state. The purpose of the usability evaluation was to assess the website's ease of use, efficiency, and user satisfaction in a representative sample of human service professionals. Users completed eleven basic search tasks with the site and report their impressions of the information presented. In addition, performance data including success, time on task, and efficiency were gathered. Implications of user satisfaction and performance data highlight the importance of stakeholder's involvement in the early stages of website design.     

Testing the Granger Noncausality Hypothesis in Stationary Nonlinear Models of Unknown Functional Form

In this article, we propose a general method for testing the Granger noncausality hypothesis in stationary nonlinear models of unknown functional form. These tests are based on a Taylor expansion of the nonlinear model around a given point in the sample space. We study the performance of our tests by a Monte Carlo experiment and compare these to the most widely used linear test. Our tests appear to be well-sized and have reasonably good power properties.     

Implementing Monte Carlo tests with p-value buckets

Software packages usually report the results of statistical tests using p-values. Users often interpret these values by comparing them with standard thresholds, for example, 0.1, 1, and 5%, which is sometimes reinforced by a star rating (***, **, and *, respectively). We consider an arbitrary statistical test whose p-value p is not available explicitly, but can be approximated by Monte Carlo samples, for example, by bootstrap or permutation tests. The standard implementation of such tests usually draws a fixed number of samples to approximate p. However, the probability that the exact and the approximated p-value lie on different sides of a threshold (the resampling risk) can be high, particularly for p-values close to a threshold. We present a method to overcome this. We consider a finite set of user-specified intervals that cover [0, 1] and that can be overlapping. We call these p-value buckets. We present algorithms that, with arbitrarily high probability, return a p-value bucket containing p. We prove that for both a bounded resampling risk and a finite runtime, overlapping buckets need to be employed, and that our methods both bound the resampling risk and guarantee a finite runtime for such overlapping buckets. To interpret decisions with overlapping buckets, we propose an extension of the star rating system. We demonstrate that our methods are suitable for use in standard software, including for low p-value thresholds occurring in multiple testing settings, and that they can be computationally more efficient than standard implementations.     

农村地区食品安全监管配套制度的完善与落实

自2009年《食品安全法》颁布至今,我国农村地区的食品安全事件依旧频发,《食品安全法》在农村地区的实施效果远不如城市。造成这种状况的原因除长期以来存在的城乡二元结构和农村居民自身生活习惯等问题外,更主要的是《食品安全法》作为一部在全国范围内统一实施的法律,其明显缺乏专门针对农村食品经营主体的监管配套制度,从而使该法在广大农村地区实施的过程中监管能力明显不足。据此,提出构建食品安全监管在农村地区的配套制度,加强技术监管和信息化管理以及充分发挥社会共治等建议。     

非常时期列宁关于粮食生产和农村工作的思想及其当代意义

苏俄非常时期,列宁在解决粮食危机的过程中提出了十分丰富的发展粮食生产及农村工作的思想。他提出,“粮食问题是一切问题的基础”,进行国内战争、发展工业以及各项事业,无不依赖于充足的粮食;发展粮食生产必须重视对农业生产的投入,采用新机器和新技术;必须帮助农民获得足够的种子,以利于他们完成播种的任务。他还提出,发展粮食生产需要调动农民的生产积极性,依赖有效的农村工作。他的这些思想对于中国特色社会主义农村建设具有积极的借鉴意义。     

论食品安全事件中的良性媒体应对

食品安全事件是近年来全球公共安全问题中的热点,由于食品安全的重要性、食品安全事件的公众效应以及基于传媒的属性,媒体常将其作为关注的热点。媒体在食品安全事件中发挥着监测预警、沟通信息、舆论引导等功能,同时也存在关注视角的选择性和职业自律的松懈等不足。作为一种社会公共资源和社会监督力量,基于传媒良知和职业操守,媒体在食品安全事件中必须形成一套良性的应对机制,包括建立信息有效传播机制、建立食品安全事件相关方的沟通协调机制、建立媒体自律机制等。     

WTO巴厘一揽子协定粮食安全条款谈判:背景、进展与对策

巴厘一揽子协定为中国保障粮食安全带来了新局面。从关税及贸易总协定、乌拉圭至多哈回合时期,粮食安全关注越来越成为谈判的重点,多哈回合谈判中各大利益集团也就其自身情况表明不同的谈判立场及利益诉求。协定的达成,在确认粮食安全等非贸易关注的重要意义、公共储备计划的"和平条款"、关税配额制度改革等方面实现突破的同时,又存在文件约束力低下、取消发达国家农产品补贴目标失败、利好政策实施程序及条件复杂等缺憾。对于中国而言,应分析此次协定为增强中国的粮食获取能力带来的政策利好,继续在后续谈判中加强对粮食安全的关注,同时及时地修改中国的粮食安全相关法律法规。     

食品检测咀嚼机器人工作空间研究

为了提高食品检测效率,改善食品检测精度,增加食品检测的客观性,文章介绍了一种基于6-UPS机构的咀嚼机器人,介绍了咀嚼机器人的结构原理,求解了机构的运动学逆解,分析了机构的工作空间影响因素,利用MATLAB编程求得机构在定姿态下的工作空间。空间轮廓图表明,该机构在定姿态下能到达人类全部真实咀嚼空间,机构设计可靠,能够模拟人类咀嚼行为对食品进行检测。     

A Rejection Principle for Sequential Tests of Multiple Hypotheses Controlling Familywise Error Rates

We present a unifying approach to multiple testing procedures for sequential (or streaming) data by giving sufficient conditions for a sequential multiple testing procedure to control the familywise error rate (FWER). Together, we call these conditions a ‘rejection principle for sequential tests’, which we then apply to some existing sequential multiple testing procedures to give simplified understanding of their FWER control. Next, the principle is applied to derive two new sequential multiple testing procedures with provable FWER control, one for testing hypotheses in order and another for closed testing. Examples of these new procedures are given by applying them to a chromosome aberration data set and finding the maximum safe dose of a treatment.