基于学习任务的合作学习模式在大学英语写作中的运用

基于学习任务的合作学习模式是当前我国大学英语教学中应用较为普遍的一种学习理论。本文主要从当前全球化趋势和我国大学英语教学的现状入手,对基于学习任务的合作学习模式的基本概况进行分析,进而谈及加强大学英语写作教学中应该注意的几点具体内容。从合理进行团队分配、提供丰富的学习资源、营造浓厚的学习氛围等几方面来对我们有关基于学习任务的合作学习模式的大学英语写作的教学的具体方法进行深入探讨。     

大股东持投比例和公司绩效的因果关系研究——基于我国上市公司面板数据的格兰杰因果检验

在公司治理的分析框架中股权结构与公司绩效的关系是一个颇具争议的问题,国内外实证研究很多,但实证结果没有得到一致的结论.本文以我国201家上市公司2000～2007年的1608个面板数据为样本,应用新近发展的Panel-Data Granger因果检验方法对大股东持股比例与公司绩效的关系进行检验,发现大股东持股比例和公司绩效之间互为因果.     

体育院系试卷的信度分析

以献资料法和调查访问法对体育纺试卷的信度进行了选取定性和定量的阐述,力求为教师规范化撰写试卷分析、为测验的科学化和标准化提供参考,研究结果表明;虽然一般课程的试卷分析中较少涉及定量的信度分析,但是定性分析法不失为一种适用的方法;试卷信度分析不仅要考虑受试信度和评分信度,而且要结合测验的其他项目进行分析。     

蚯蚓素安全性毒理学评价试验

以大鼠、杂种犬为研究对象,将蚯蚓素分低、中、高剂量组拌食喂养３个月,观察其外观、行为,镜下组织学病理检查,５项血液指标和５项生化指标测试,均正常。分别停药一个月后检查,各项指标也在正常范围内,证明蝗蚓素作为新资源食品安全无毒。     

如何解答普通物理选择题

准确掌握物理学的基本理论和基本方法是正确解答选择题的关键,对定理、定律的熟练应用是迅速解题的保证。结合实例介绍了解答单选题的一些技巧:直接法、间接法、筛选法、作图法等。     

发挥考试功能提高教学质量

考试是教学过程中的一个重要环节,是检测、评价教师的教学质量和学生学习效果的基本手段。加强考试管理与研究是建立良好学风,促进教风建设,提高教育教学质量的重要保证。通过对考试功能的论述,以引起高校对考试工作的重视,真正使考试发挥其提高教学质量的作用。     

Biochemical diagnosis of liver disease

It is important that clinicians and laboratorians, including clinical chemists and pathologists, recognize and understand the clinical significance of abnormal liver function tests. The liver regulates many important metabolic functions. Hepatic injury is associated with distortion of these metabolic functions. Hepatic disease can be evaluated and diagnosed by determining serum concentrations of a number of serum analytes. Many serum analytes exist to assist in the biochemical diagnosis of liver disease. The focus of this paper is on the analytes which are associated with hepatic necrosis, cholestasis, defects in excretion and end stage hepatic disease which results in decreased synthetic function. The abnormalities of these serum analytes will be correlated with the important types of liver disease.     

建立外语网络化教学模式,努力实施素质教育

由“应试教育”向“素质教育”的转变,是外语教育、教学思想的一场变革。它证明了长期以来就能够感觉到的东西：摒弃那种存在已久、根深蒂固的所谓“传统教学模式”;建立网络环境下的外语教学模式,努力实施“素质教育”,培养学生外语的综合应用能力。     

我国企业负债期限结构决策研究——基于问卷调查及上市公司公开数据的实证分析

本文运用多种非参数检验及方差分析方法,结合问卷调查数据及上市公司公开数据,研究了我国企业负债期限结构决策的影响因素。研究发现短期债务的易获得性及低成本是我国企业决定负债期限时考虑的最主要的因素;由于长期债务融资能力受到限制,我国企业的负债期限管理能力不强;企业特征对负债期限决策时考虑的因素有一定影响。     

Determining the SARS-CoV-2 serological immunoassay test performance indices based on the test results frequency distribution

IntroductionCoronavirus disease 2019 (COVID-19) is known to induce robust antibody response in most of the affected individuals. The objective of the study was to determine if we can harvest the test sensitivity and specificity of a commercial serologic immunoassay merely based on the frequency distribution of the SARS-CoV-2 immunoglobulin (Ig) G concentrations measured in a population-based seroprevalence study.Materials and methodsThe current study was conducted on a subset of a previously published dataset from the canton of Geneva. Data were taken from two non-consecutive weeks (774 samples from May 4-9, and 658 from June 1-6, 2020). Assuming that the frequency distribution of the measured SARS-CoV-2 IgG is binormal (an educated guess), using a non-linear regression, we decomposed the distribution into its two Gaussian components. Based on the obtained regression coefficients, we calculated the prevalence of SARS-CoV-2 infection, the sensitivity and specificity, and the most appropriate cut-off value for the test. The obtained results were compared with those obtained from a validity study and a seroprevalence population-based study.ResultsThe model could predict more than 90% of the variance observed in the SARS-CoV-2 IgG distribution. The results derived from our model were in good agreement with the results obtained from the seroprevalence and validity studies. Altogether 138 of 1432 people had SARS-CoV-2 IgG ≥ 0.90, the cut-off value which maximized the Youden’s index. This translates into a true prevalence of 7.0% (95% confidence interval 5.4% to 8.6%), which is in keeping with the estimated prevalence of 7.7% derived from our model. Our model can provide the true prevalence.ConclusionsHaving an educated guess about the distribution of test results, the test performance indices can be derived with acceptable accuracy merely based on the test results frequency distribution without the need for conducting a validity study and comparing the test results against a gold-standard test.