高职高专院校英语专业学生同伴纠错类型研究

统计分析了西部地区某高职高专院校英语读书报告中同伴识别和修改的错误。结果发现：纠错类型中除了Larsen-Freeman and long（2000）归纳的二语习得偏误类型外,还存在其他偏误;学生的纠错意识和能力较弱且主要集中在句子内部;外语学习过程中也会发生磨蚀现象。     

Using E-Health Programs to Overcome Barriers to the Effective Treatment of Mental Health and Addiction Problems

E-Health programs for mental illness and addictive behaviors have recently emerged as potentially useful self-help resources. Health care professionals will soon have the option of referring clients to free-to-end-user online, expert-moderated e-health programs as complementary means of assisting clients. Such programs will have significant implications for developing improved stepped models of care. This article describes various e-health programs and lessons learned related to access, promotion, user demographics, and patterns of use. In addition, validation procedures, effectiveness and attrition rates, fitting and tailoring, and qualitative analyses of social networks are described. It is difficult to validate e-health programs that are completely anonymous and do not require registration, personal interaction, or membership fees. As competition emerges in the budding e-health industry, best practice guidelines will need to be developed for collecting data and evaluating the utility of these programs.     

外语词汇磨蚀的语言学表征分析

语言磨蚀的突出表现是词汇提取失败。大学一年级新生的高中英语词汇磨蚀的测试结果表明：在语音和词形上相似或相同,语义关系复杂的词汇易被磨蚀。受蚀词汇的语言学表征为：在语音上,弱音节的、音素组合关系为“聚合”关系的、总体韵律相似的词汇易磨蚀;词形上,词缀的语义易被磨蚀,词形相似且伴有语音相似的词汇易磨蚀,词汇的首尾成份相似的词汇也易磨蚀;语义上,语义范畴的层级关系复杂的词汇易磨蚀。词汇磨蚀可以根据其语言学表征分为四类：耐蚀词汇、易蚀词汇、半蚀词汇和全蚀词汇。     

The effects of propensity score weighting on attrition biases in attitudinal,behavioral, and socio-demographic variables in a short-term web-based panel survey

Propensity score weighting often is used to correct for attrition biases in panel surveys. While methodological literature exists on the logic of propensity score weighting and its practical applications, an in-depth discussion is lacking on the effects of using this weighting to correct for attrition biases in attitudinal, behavioral, and socio-demographic variables. By applying a split panel design, we assessed the effects of weighting on attrition biases in 48 attitudinal, 38 behavioral, and 27 socio-demographic variables. Our findings suggest – while acknowledging the estimate-specific nature of bias – first, that biases vary across these types of variables and second, that the effects of propensity score weighting are not homogeneous across the types. Accordingly, a sole reliance on socio-demographics to evaluate attrition in the present panel survey would have resulted in an underestimation of the biases of attitudinal variables and an overestimation of the ability of weighting to cure the negative effects of attrition in behavioral variables.     

Handling missing data in numeric analyses

ABSTRACT

Social science datasets usually have missing cases, and missing values. All such missing data has the potential to bias future research findings. However, many research reports ignore the issue of missing data, only consider some aspects of it, or do not report how it is handled. This paper rehearses the damage caused by missing data. The paper then briefly considers eight different approaches to handling missing data so as to minimise that damage, their underlying assumptions and the likely costs and benefits. These approaches include complete case analysis, complete variable analysis, single imputation, multiple imputation, maximum likelihood estimation, default replacement values, weighting, and sensitivity analyses. Using only complete cases should be avoided wherever possible. The paper suggests that the more complex, modelling approaches to replacing missing data are based on questionable methodological and philosophical assumptions. And they may anyway not have clear advantages over simpler approaches like default replacements. It makes sense to report all possible forms of missing data, report everything that is known about the characteristics of cases missing values, conduct simple sensitivity analyses of the potential impact of missing data on the substantive results, and retain the knowledge of missingness when using any form of replacement value.     

非英语专业高校毕业生英语损耗诸因素相互关联的实证研究——以长三角地区非英语专业大学毕业生为例

语言磨蚀在国外经历几十年的发展,涌现出大量研究成果。但这方面研究在国内只有寥寥几篇介绍性的论文,尚缺乏实证研究。本文以长三角企业中从业的1000名非英语专业大学生为样本,调查他们英语损耗的要素,重点对"损耗前水平、损耗时间、英语接触量、年龄、英语学习方式、社会情感因素和读写能力"八大因素进行调查,采用SPSS 19.0和NVIVO 10对调查数据进行分析。研究发现,社会情感因素在英语损耗的诸要素中有着特殊的影响。这一发现能从很大程度上回答我国英语教学耗时低效的根本原因。     

企业竞争中的消耗战及其模型研究

企业竞争中消耗战无处不在。如何选择正确的消耗战策略,直接关系着企业的存亡。本文拟以博弈论的方法,建立企业竞争中的消耗战数学模型,分别对其离散时间模型及其均衡、离散时间模型过度到连续时间模型、完全信息模型及其均衡、不完全信息模型及其均衡进行系统分析,为企业的消耗战策略提供理论依据。     

Bargaining,Reputation, and Equilibrium Selection in Repeated Games with Contracts

Consider a two‐person intertemporal bargaining problem in which players choose actions and offers each period, and collect payoffs (as a function of that period's actions) while bargaining proceeds. This can alternatively be viewed as an infinitely repeated game wherein players can offer one another enforceable contracts that govern play for the rest of the game. Theory is silent with regard to how the surplus is likely to be split, because a folk theorem applies. Perturbing such a game with a rich set of behavioral types for each player yields a specific asymptotic prediction for how the surplus will be divided, as the perturbation probabilities approach zero. Behavioral types may follow nonstationary strategies and respond to the opponent's play. In equilibrium, rational players initially choose a behavioral type to imitate and a war of attrition ensues. How much should a player try to get and how should she behave while waiting for the resolution of bargaining? In both respects she should build her strategy around the advice given by the “Nash bargaining with threats” (NBWT) theory developed for two‐stage games. In any perfect Bayesian equilibrium, she can guarantee herself virtually her NBWT payoff by imitating a behavioral type with the following simple strategy: in every period, ask for (and accept nothing less than) that player's NBWT share and, while waiting for the other side to concede, take the action Nash recommends as a threat in his two‐stage game. The results suggest that there are forces at work in some dynamic games that favor certain payoffs over all others. This is in stark contrast to the classic folk theorems, to the further folk theorems established for repeated games with two‐sided reputational perturbations, and to the permissive results obtained in the literature on bargaining with payoffs as you go.     

Analyzing attrition in a community-based literacy program

Attrition presents a challenge for research, especially when it affects groups differentially. The present study used the strategy proposed by Cook and Campbell (1979) to investigate attrition in a community-based literacy program. The relationship of attrition to person-centered and program-centered variables, and the interactions between person-centered and program-centered variables were examined in 287 Head Start families. Thus, data from this program were used to illustrate methods for examining attrition and determine its effects. This examination revealed differences among the intervention groups in the pattern of attrition. There were interactions between intervention program-centered characteristics and person-centered characteristics of the participants that could affect the validity of the study and limit the generalizability of the results. Suggestions for dealing with these problems and preventing attrition are discussed.     

Difference-in-difference estimation by FE and OLS when there is panel non-response

We show that the ordinary least squares (OLS) and fixed-effects (FE) estimators of the popular difference-in-differences model may deviate when there is time-varying panel non-response. If such non-response does not affect the common-trend assumption, then OLS and FE are consistent, but OLS is more precise. However, if non-response is affecting the common-trend assumption, then FE estimation may still be consistent, while OLS will be inconsistent. We provide simulation as well as empirical evidence for this phenomenon to occur. We conclude that in case of unbalanced panels, deviating OLS and FE estimates should be considered as evidence that non-response is not ignorable for the differences-in-differences estimation.