The Economic Efficiency of Sampling Size: The Case of Beef Trim

The economically optimal sample size in a food safety test balances the marginal costs and marginal benefits of increasing the sample size. We provide a method for selecting the sample size when testing beef trim for Escherichia coli O157:H7 that equates the averted costs of recalls and health damages from contaminated meats sold to consumers with the increased costs of testing while allowing for uncertainty about the underlying prevalence rates of contamination. Using simulations, we show that, in most cases, the optimal sample size is larger than the current sample size of 60 and, in some cases, it exceeds 120. Moreover, lots with a lower prevalence rate have a higher expected damage because contamination is more difficult to detect. Our simulations indicate that these lots have a higher optimal sampling rate.     

悲剧意识与文化传统

人类发展和人类社会形态更替过程都包含了悲剧性。只有人们正确地认识和把握现实的悲剧性,并想改变自己的生存困境,悲剧意识才可能形成。悲剧意识是指在人类发展过程和社会发展进程中,体现在某些人物身上的那种“无为而为”的心理倾向,即某些人明知他们将来的所作所为一定会失败(实际上也会失败),却仍然锐意去追求、奋斗、牺牲的心理趋势。它由两个部分构成:一、人类生存和社会发展的困境;二、人类对人类生存和社会发展困境的超越、应战的精神。西方文化决定了它的悲剧意识表现形态,西方人的悲剧意识表现得深刻、彻底,中国文化决定了它的悲剧意识表现形态,中国人悲剧意识表现得浮泛、留有余地。     

The performance of the income protection system for older adults in Ecuador and future challenges

The objective of this article is to analyse the performance of Ecuador’s pension system and the challenges it will face in the future. Over the last 13 years, the pension system has made significant advances in terms of coverage and adequacy. However, demographic ageing is straining the financial sustainability of the contributory scheme. In this context, a number of public policy areas are identified, in terms of parameters and structures, which, together with the expansion of non-contributory coverage, could provide a more equitable and sustainable scheme.     

中国人的悲剧意识

一提到悲剧意识,人们马上想到它是对悲剧性现实的反映,但现实的悲剧性并不一定总会随之产生一种具有意识形态性的悲剧意识,真正的悲剧意识是建立在对悲剧性现实的理性把握和一定的文化背景基础之上的。具有深沉而厚重的文化底蕴的中国人的悲剧意识亦如此,同时又赋予了悲剧意识新的内容,即蕴涵在具体而现实的爱情和社会理想悲剧中的关于宇宙人生的生命悲剧意识。     

设计教育：挑战、问题、前景

论述全球化教育给我国设计教育带来的挑战,剖析我国当前设计教育存在的问题,阐明我国设计教育在人才培养上的发展前景。     

对书法生命意象的阐释

书法不是图画,不可能用具体形象来表现生命力,只能通过抽象的文字符号使之成为象征人格的生命,从而使接受者打破心理上静止的平衡状态,在信息流中涌起情感浪花,获得生命活力的美感。而要唤起生命活力,必须在文字符号的基础上,注入书家主体的生命意识,使字“变调”转换为有个性的情感符号,成为审美信息。     

20世纪初上海城市客运业与官商互动模式的嬗变

上海城市区域不断扩大,导致城市人口形成空间活动固定模式,产生了现代公共交通方式。华界现代公共交通基本由民间社会集资兴办,民族交通企业创办了华界地区现代公共交通。在民间资本式微的情况下,上海市政府公用局尝试性地运用政府的独特优势,整合相关社会资源,积极介入区域公共交通的建设与发展之中,取得了初步成效。同时公用局坚持华界公共交通“以公营为宜”的主张,加强对商办交通企业监管,引起了监管方式的争执。     

论体育锻炼与心理健康的辩证关系

本文通过对现在大学生心理健康情况的调查分析,论证了体育锻炼对保持心理健康的重要性,为现代大学生的人格完善和克服心理障碍找到了方法。     

Regularization and variable selection via the elastic net

Summary.  We propose the elastic net, a new regularization and variable selection method. Real world data and a simulation study show that the elastic net often outperforms the lasso, while enjoying a similar sparsity of representation. In addition, the elastic net encourages a grouping effect, where strongly correlated predictors tend to be in or out of the model together. The elastic net is particularly useful when the number of predictors ( p ) is much bigger than the number of observations ( n ). By contrast, the lasso is not a very satisfactory variable selection method in the p ≫ n case. An algorithm called LARS-EN is proposed for computing elastic net regularization paths efficiently, much like algorithm LARS does for the lasso.     

高校学生思想政治教育前瞻性思考

高校规模化、学生个性化、观念多元化、信息网络化、后勤社会化、就业市场化是新世纪新阶段高校学生思想政治教育面临的新情况。高校思想政治教育必须转变传统的教育模式,努力探索思想政治教育的新思路新途径。