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581.
Daniel Kreisman 《Social science research》2012,41(6):1429-1450
I compare language learning trajectories for Black and White children over the first 3 years of life using data from the Early Head Start Research and Evaluation study (EHSRE) in order to determine the timing and source of divergence in early language skill. Results indicate that that while controlling for racial differences in family background and a measure of the home language environment cannot entirely account for disparities in language acquisition, interactions between age, race and maternal education, and between race and a time-varying measure of the home language environment play a significant role. I show that returns to parental education and the home language environment, in terms of language learning, are higher for White children than their Black peers. Specification checks confirm that these results are robust to alternate definitions of child language and the home language environment, and that no interactions between race, age and any of the other covariates are significant. I discuss possible explanations for these race specific education gradients, including measurement error and test bias. In addition, I address relevant empirical issues in estimating language growth with respect to linguistic inputs and the home language environment. 相似文献
582.
根据国家教育部2000年颁布的新《高等学校英语专业英语教学大纲》,本文论述了英语专业基础英语课程教学中存在的具体问题,对吉林农业大学英语专业基础英语课程教学模式的系列改革进行了分析,并总结了所取得的成果与经验。 相似文献
583.
传统的非英语专业研究生英语教学模式已不能适应为社会培养创新复合型人才的需要,对其进行改革势在必行。文章以建构主义学习理论和语言输入与输出理论为基础,构建了一种利用互联网资源辅助研究生英语课堂的教学模式,目的旨在提高非英语专业硕士研究生的英语交际能力。 相似文献
584.
Adrienne Holz Ivory 《Journal of homosexuality》2019,66(1):31-59
This study examines how sexual orientation of couples featured in magazine advertisements affects heterosexual viewers’ responses using the elaboration likelihood model as a framework. A 3 × 2 × 2 × 3 experiment tested effects of sexual orientation, argument strength, involvement, and attitudes toward homosexuality on heterosexuals’ attitudes toward the couple, advertisement, brand, and product, purchase intentions, and recall. Results indicate that consumers were accepting of ads with lesbian portrayals. Participants showed more negative attitudes toward gay male portrayals, but attitudes toward heterosexual and lesbian ads were similar. This effect was moderated by participants’ attitudes toward homosexuals. Low-involvement consumers showed more negative attitudes toward homosexual portrayals than toward heterosexual portrayals, indicating that sexual orientation may have served as a peripheral cue negatively impacting attitudes toward the couple and ad under low elaboration. These effects were not observed for attitudes toward the brand and product, purchase intentions, or recall. 相似文献
585.
城镇化是我国民族地区经济社会发展的必经阶段。探索民族地区的城镇化发展模式及创新路径,对于加速民族地区现代化进程、转变民族地区经济增长方式以及实现社会安定团结具有重要的推动作用。文章在对民族地区城镇化发展现状描述的基础之上,归纳概括出城镇化运行的四大矛盾;并全面总结出旅游产业带动型、工业发展助推型、边境贸易推动型、草原牧业发展型四大类型的城镇化发展模式;通过构建民族地区城镇化发展的愿景框架,结合民族地区的发展实际,最终提出坚持绿色低碳,发展城镇化的生态文明建设,强化产城融合,持续释放城镇化的发展活力,深化制度改革,实现城镇化发展质量的提升及保持文化传承,不断彰显城镇化的民族特色等城镇化发展的创新路径。 相似文献
586.
构建恰当资产组合来减少风险, 是投资组合理论研究的重要目标.由于金融时间序列的波动往往会伴随着持续性特征, 该种特性会增大组合未来收益的风险.本文通过构建随机波动模型序列持续性最优投资组合模型, 以降低金融资产波动的持续性特征对组合收益波动的影响;并通过研究其分散化水平, 考察该投资组合构建方法的有效性与稳健性.研究发现:与均值方差的组合模型相比较, 序列持续性组合的风险分散化水平更好.此研究在资产组合选择方面, 具有较为重要的理论价值及实践意义. 相似文献
587.
考虑同一企业内不同项目间关联关系的情况下,基于研发项目的数量将研发网络分为不同子网络。借鉴SIS模型构建了R&D网络风险传播动力学模型,并对该模型进行了数理解析与仿真分析。结果表明:R&D网络风险传播阈值是由不同子网络的拓扑结构以及企业内不同项目间的关联程度共同决定的;考虑项目关联的研发网络风险传播阈值小于不考虑关联关系的研发网络风险传播阈值;项目间关联关系的企业个数及项目间的关联程度对风险在不同子网络上的传播速度与传播范围均具有影响。该研究成果对于提高研发网络抗风险能力具有重要意义。 相似文献
588.
带基约束的投资组合问题是近年来投资组合领域的热点问题,但是参数不确定性直接影响了模型的效果。带基约束的投资组合问题所涉及的参数不仅包括以往研究认为非常重要的预期收益率,还包括控制投资组合规模的稀疏度,尤其是最优稀疏度估计方面的专门研究还十分匮乏。为了使带基约束的投资组合模型更好地为投资决策服务,本文从投资者效用出发,用双层规划的思想构建了带基约束的投资组合双层参数估计模型。然后根据模型的特点,设计了无导数优化算法框架,并基于ADMM对算法子问题进行求解。本文实验针对真实的市场数据给出了预期收益率和最优稀疏度的估计,接着通过与等权重策略和含上下界约束的均值-方差模型进行比较,说明了模型及算法的有效性和实用性。最后,将本文提出的双层参数估计模型推广到了更一般的形式。 相似文献
589.
The shared resource hypothesis suggests that married couples share the same environmental resources, which shape their health concordance. This study tests its cross‐national applicability. Cross‐sectional 2012–2013 Health and Retirement Study data from China, England, Mexico, and the United States were analyzed. Heterosexual couples (age ≥60) who were married or partnered were studied (N = 20,565 pairs). Dyadic data were analyzed by multilevel models to examine the effect of self and spousal social and physical health statuses on depressive symptoms. Regression models were used to test the relationship between couples' shared resources and depressive symptom concordance. Results indicated both husbands and wives' depressive symptoms were associated with their own and spouses' social and health statuses. Most couple‐level resources were insignificant predictors for Chinese and Mexican couples' concordance, but having more social and financial resources was associated with higher concordance among British and American couples. Self‐reported health was the most consistent predictor in all countries. The shared resource hypothesis was more applicable to depressive symptom concordance within couples in the United States and England, but not in China and Mexico. Couple‐centered intervention is suggested for clinical practice, and the spousal effect should be considered in policymaking. 相似文献
590.
Nicole Gravina Bob Cummins John Austin 《Journal of Organizational Behavior Management》2017,37(3-4):316-331
ABSTRACTA recent prevalence of high visibility catastrophic events has garnered increased attention to process safety issues. While the use of Behavior-Based Safety interventions demonstrate a reduction in workplace injuries by targeting employee behavior, we believe that process safety requires a greater focus on the behavior of leaders (e.g., creating and executing strategy). One effective method to begin targeting leader behavior for the improvement of process safety is to teach leaders about the principles of behavior, including ways by which the science may be applied within their own organizational models. 相似文献