浅论缩短反馈时间在中学英语写作教学中的作用

本文通过调查一所普通中学学生对教师英语作文反馈时间的偏好并进行实验研究,利用统计学的描述性统计,独立/相关样本T检验分析方法,作者发现缩短反馈时间确实能够提高学生的英语写作水平,并结合其对教学的启示进行了讨论。     

A case of suspected child abuse by an adolescent mother: The use of short-term psychotherapy

The incidence of pregnancy during adolescence has escalated dramatically in recent years, with an estimated half a million infants born to teenagers each year in the United States. A disproportionately high amount of child abuse and/or neglect is encountered among adolescent parents, underscoring the need for an effective intervention strategy. Short-term psychotherapy may be beneficial in these cases for forging a therapeutic alliance expeditiously and rigorously challenging the patient's resistance. The case described involves alleged abuse by a 16-year-old mother. An intervention was designed to clarify the allegations surrounding the abusive incident, help the mother confront episodes of loss in her own life and overcome feelings of hopelessness engendered by separation from her infant.     

The time‐dependent “cure‐death” model investigating two equally important endpoints simultaneously in trials treating high‐risk patients with resistant pathogens

A variety of primary endpoints are used in clinical trials treating patients with severe infectious diseases, and existing guidelines do not provide a consistent recommendation. We propose to study simultaneously two primary endpoints, cure and death, in a comprehensive multistate cure‐death model as starting point for a treatment comparison. This technique enables us to study the temporal dynamic of the patient‐relevant probability to be cured and alive. We describe and compare traditional and innovative methods suitable for a treatment comparison based on this model. Traditional analyses using risk differences focus on one prespecified timepoint only. A restricted logrank‐based test of treatment effect is sensitive to ordered categories of responses and integrates information on duration of response. The pseudo‐value regression provides a direct regression model for examination of treatment effect via difference in transition probabilities. Applied to a topical real data example and simulation scenarios, we demonstrate advantages and limitations and provide an insight into how these methods can handle different kinds of treatment imbalances. The cure‐death model provides a suitable framework to gain a better understanding of how a new treatment influences the time‐dynamic cure and death process. This might help the future planning of randomised clinical trials, sample size calculations, and data analyses.     

服务业三种生产模式的选择：外包、FDI和本国生产

外包、FDI和本国生产是服务业国际化战略中最重要的三种生产模式。本文通过建立发达国家的国际化选择模型,利用柯布道格拉斯函数,根据最小成本原则,比较了外包模式、FDI模式和本国生产模式下的成本差异;通过建立短期和长期的国际化选择模型,分析了发达国家如何将服务业产品在外包、FDI和本国生产三种生产模式之间进行分配。并对我国如何做好服务业国际转移的承接工作提出了建议。     

中国政府教育援外短期培训项目有效性分析——基于南京、天津四所高校援外培训的实证研究

短期援外培训项目是我国援外政策的一个重要组成部分，但是缺乏对影响这类项目的有效性因素的实证研究。本文建立了一个短期援外培训项目有效性的分析框架，对南京、天津四所高校承担的部分援外培训项目进行了调研，使用偏最小二乘法对模型进行了验证。结果表明，我国短期援外培训项目的有效性与课程质量、培训机构及管理人员的执行力之间存在显著的正相关关系。文章最后对如何提高教育援外短期培训项目的有效性提出了相关政策建议。     

Comparative Potency Method for Cancer Risk Assessment: Application to Diesel Particulate Emissions1

An estimation of the human lung cancer “unit risk” from diesel engine particulate emissions has been made using a comparative potency approach. This approach involves evaluating the tumorigenic and mutagenic potencies of the particulates from four diesel and one gasoline engine in relation to other combustion and pyrolysis products (coke oven, roofing tar, and cigarette smoke) that cause lung cancer in humans. The unit cancer risk is predicated on the linear nonthreshold extrapolation model and is the individual lifetime excess lung cancer risk from continuous exposure to 1 μg carcinogen per m³ inhaled air. The human lung cancer unit risks obtained from the epidemiologic data for coke oven workers, roofing tar applicators, and cigarette smokers were, respectively, 9.3 × 10^?4, 3.6 × 10^?4, and 2.2 × 10^?6 per μg particulate organics per m³ air. The comparative potencies of these three materials and the diesel and gasoline engine exhaust particulates (as organic extracts) were evaluated by in vivo tumorigenicity bioassays involving skin initiation and skin carcinogenicity in SENCAR mice and by the in vitro bioassays that proved suitable for this analysis: Ames Salmonella microsome bioassay, L5178Y mouse lymphoma cell mutagenesis bioassay, and sister chromatid exchange bioassay in Chinese hamster ovary cells. The relative potencies of the coke oven, roofing tar, and cigarette smoke emissions, as determined by the mouse skin initiation assay, were within a factor of 2 of those determined using the epidemiologic data. The relative potencies, from the in vitro bioassays as compared to the human data, were similar for coke oven and roofing tar, but for the cigarette smoke condensate the in vitro tests predicted a higher relative potency. The mouse skin initiation bioassay was used to determine the unit lung cancer risk for the most potent of the diesel emissions. Based on comparisons with coke oven, roofing tar, and cigarette smoke, the unit cancer risk averaged 4.4 × 10^?4. The unit lung cancer risks for the other, less potent motor-vehicle emissions were determined from their comparative potencies relative to the most potent diesel using three in vitro bioassays. There was a high correlation between the in vitro and in vivo bioassays in their responses to the engine exhaust particulate extracts. The unit lung cancer risk per μg particulates per m³ for the automotive diesel and gasoline exhaust particulates ranged from 0.20 × 10^?4 to 0.60 × 10^?4; that for the heavy-duty diesel engine was 0.02 × 10^?4. These unit risks provide the basis for a future assessment of human lung cancer risks when combined with human population exposure to automotive emissions.     

Generic Assessment Endpoints Are Needed for Ecological Risk Assessment

This article presents arguments for the development of generic assessment endpoints for ecological risk assessment. Generic assessment endpoints would be ecological entities and attributes that are assumed to be worthy of protection in most contexts. The existence of generic assessment endpoints would neither create a requirement that they be used in every assessment nor preclude the use of other assessment endpoints. They would simply be a starting point in the process of identifying the assessment endpoints for a particular assessment. They are needed to meet legal mandates, to provide a floor for environmental degradation, to provide some consistency in environmental regulation, as exemplars for site- or project-specific assessment endpoints, to allow development of methods and models, to give risk managers the courage to act, for screening and site-independent assessments, to support environmental monitoring, to facilitate communication, and to avoid paralysis by analysis. Generic assessment endpoints should include not only a list of entities and attributes, but also explanations of each endpoint, guidance on their use and interpretation, and measures and models that could be used to estimate them.     

Explorative study into support needs of caregivers in short-term foster care regarding problem behaviour and dealing with biological parents

Family supporting foster care (FSFC) is a directly accessible, short-term and preventive form of foster care for children under the age of 12. Caregivers in this type of foster care need comprehensive support to deal with their complex tasks. In this contribution, the support needs arising from the behaviour of the foster child as well as concerning dealing with the biological parents of 85 Flemish FSFC-parents are examined, as these are areas FSFC-parents specifically ask support for. These support needs are evaluated for possible links with child and foster parent characteristics. More experienced foster parents and foster parents with a foster child showing more externalising problem behaviour ask for more support in managing the child's behaviour.     

Exact calculation of power and sample size in bioequivalence studies using two one‐sided tests

The number of subjects in a pharmacokinetic two‐period two‐treatment crossover bioequivalence study is typically small, most often less than 60. The most common approach to testing for bioequivalence is the two one‐sided tests procedure. No explicit mathematical formula for the power function in the context of the two one‐sided tests procedure exists in the statistical literature, although the exact power based on Owen's special case of bivariate noncentral t‐distribution has been tabulated and graphed. Several approximations have previously been published for the probability of rejection in the two one‐sided tests procedure for crossover bioequivalence studies. These approximations and associated sample size formulas are reviewed in this article and compared for various parameter combinations with exact power formulas derived here, which are computed analytically as univariate integrals and which have been validated by Monte Carlo simulations. The exact formulas for power and sample size are shown to improve markedly in realistic parameter settings over the previous approximations. Copyright © 2014 John Wiley & Sons, Ltd.