On Thanksgiving and Collective Memory: Constructing the American Tradition

Relying on the approach by Maurice Halbwachs who argued that collective memory is based on contemporary interests and concerns, this article shows how Thanksgiving has changed over time in accordance with the ideas of the day. Aspects of the analysis support Barry Schwartz's theory that commemoration reflects the historical past. Similar to the pilgrims' celebration, many people commemorate Thanksgiving by, for example, feasting and praying. But in contrast to Schwartz's thought, this paper also shows that there are other elements of traditions that have minimal connection with the original event. Forms of commemoration like the Macy's Day Parade challenge the idea that commemoration and celebration contain some connection to the initial occasion. In general, the findings lend support to historical research and theories that implement social constructionist approaches.     

影响听力理解的主观因素

本文主要就影响听力理解的几个主观因素即语言知识 ,背景知识和短时记忆容量进行了分析 ,指出在听力训练中应加强这几方面的能力培养 ,在听力过程中应合理运用背景知识 ,扩大短时记忆的容量。     

资源型城市需要加快发展第三产业

本文以东营市、大庆市为例 ,分析了矿产资源型城市第三产业发展的薄弱性 ,并在阐述资源型城市发展第三产业重要性的基础上 ,提出了东营市第三产业发展的目标及战略选择 ,以此来反映资源型城市第三产业发展的方向。     

内核级并发通信的研究

提出了一种内核级并发消息通信机制。该机制采用对象传送协议和动态线程池技术,并通过会话控制完成数据的收发过程,将线程池设计为二级阻塞队列来暂缓线程的撤销过程,从而保证既能够快速响应客户请求,又可减少因频繁创建和撤销线程而消耗系统的资源和时间,为分布式操作系统提供了高效可靠的通信服务。     

陀思妥耶夫斯基与福克纳比较论纲

作为伟大的作家,陀思妥耶夫斯基与福克纳在总体倾向、艺术手段与思想指归上存在着巨大的差异性和惊人的一致性。对他们的比较,是一件饶有兴味也极富挑战意义的事情。     

Statistical Distributions of Daily Breathing Rates for Narrow Age Groups of Infants and Children

Children may be more susceptible to toxicity from some environmental chemicals than adults. This susceptibility may occur during narrow age periods (windows), which can last from days to years depending on the toxicant. Breathing rates specific to narrow age periods are useful to assess inhalation dose during suspected windows of susceptibility. Because existing breathing rates used in risk assessment are typically for broad age ranges or are based on data not representative of the population, we derived daily breathing rates for narrow age ranges of children designed to be more representative of the current U.S. children's population. These rates were derived using the metabolic conversion method of Layton (1993) and energy intake data adjusted to represent the U.S. population from a relatively recent dietary survey (CSFII 1994–1996, 1998). We calculated conversion factors more specific to children than those previously used. Both nonnormalized (L/day) and normalized (L/kg-day) breathing rates were derived and found comparable to rates derived using energy estimates that are accurate for the individuals sampled but not representative of the population. Estimates of breathing rate variability within a population can be used with stochastic techniques to characterize the range of risk in the population from inhalation exposures. For each age and age-gender group, we present the mean, standard error of the mean, percentiles (50th, 90th, and 95th), geometric mean, standard deviation, 95th percentile, and best-fit parametric models of the breathing rate distributions. The standard errors characterize uncertainty in the parameter estimate, while the percentiles describe the combined interindividual and intra-individual variability of the sampled population. These breathing rates can be used for risk assessment of subchronic and chronic inhalation exposures of narrow age groups of children.     

Non-ignorable missing covariate data in survival analysis: a case-study of an International Breast Cancer Study Group trial

Summary.  Non-ignorable missing data, a serious problem in both clinical trials and observational studies, can lead to biased inferences. Quality-of-life measures have become increasingly popular in clinical trials. However, these measures are often incompletely observed, and investigators may suspect that missing quality-of-life data are likely to be non-ignorable. Although several recent references have addressed missing covariates in survival analysis, they all required the assumption that missingness is at random or that all covariates are discrete. We present a method for estimating the parameters in the Cox proportional hazards model when missing covariates may be non-ignorable and continuous or discrete. Our method is useful in reducing the bias and improving efficiency in the presence of missing data. The methodology clearly specifies assumptions about the missing data mechanism and, through sensitivity analysis, helps investigators to understand the potential effect of missing data on study results.     

网上购物风险来源、类型及其影响因素研究

从风险来源的角度深入地研究了网上购物感知风险类型与其相对强度,对于企业从风险来源上降低和管理网上风险具有重要的指导意义.文章发现消费者在网上购物时,风险主要来源于产品本身、远距离交易、互联网这种交易模式和网站这四个方面.研究结果揭示了,当消费者在网上购物的时候,所感受到最强烈的三个风险分别是,来自于产品本身的产品绩效风险、来自于远距离交易的服务风险和来自于网站的来源风险.最后,研究还发现,消费者网上购物感知风险的强弱与消费者的年龄、网络购物频率之间存在较强的相关性,年龄越大,感知风险越强;网上购物频率越高,感知风险越低.