中国主要禾本科植物颖果形态的基本类型与系统分类

本文在观察了31个族109个属324种禾本科植物果实形态的基础上，探讨了重要性状演化的趋势及其与分布区和生境条件的关系。根据果实大小，整体形状，腹面和脐的形态，胚与果的长度比值，果端有无茸毛，花柱是否宿存，尤其横切面轮廓等，将禾本科的颖果形态划分为三大类型七个亚型。  经过与细胞染色体、胚体、幼苗和植株各方面数据的互相印证，证明与颖果形态的七个基本类型相对应，在系统分类上是七个亚科。     

Accelerated Online Learning: Perceptions of Interaction and Learning Outcomes Among African American Students

This study investigated student interaction, satisfaction, and performance in accelerated online learning environments with the use of an online learning course-management system. The interactions assessed in this study included learner–learner interaction, learner–instructor interaction, and learner–content interaction. The participants were African American students from a university in the southeastern United States. Quantitative approaches including correlation and regression analyses were performed to examine the contribution of interaction predictors to student satisfaction as well as the relationship between student satisfaction and student performance. In addition, Internet self-efficacy and its impact on interaction was investigated. The results showed that learner–content interaction was the only significant predictor of student satisfaction whereas interaction among students or with the instructor did not significantly predict student satisfaction. Internet self-efficacy was positively correlated with three types of interaction. Student satisfaction was found to be related to student performance.     

改革物理实验教学培养学生创新能力

指出了传统实验教学中存在的问题.提出了改革物理实验教学,培养学生创新能力的途径.     

Both Theory and Practice: Science Literacy Instruction and Theories of Reading

Many journal articles detail recommendations to naturally integrate literacy instruction into content-area classes, particularly science, claiming that such instructional practices will support both literacy and content-knowledge acquisition. This begs the question, are the literacy strategies recommended for content-area instruction founded in established educational theories? The purpose of the current study is to examine the implicit and explicit theories driving science disciplinary literacy instruction. Theories assist in organizing and advancing research in a systematic manner. Information on the status of theory is essential to both practitioners (who are implementing strategies) and researchers (who are making recommendations for classroom instruction). Our study revealed that in science literacy, vocabulary instructional practices are frequently supported with Schema and Dual-Coding theories. Articles also frequently used theories grounded in social dynamics, including social constructionism and sociocultural perspective, to support literacy instruction. However, recommendations for other aspects of instructional practices in science literacy are generally not well-grounded in major reading theories.     

新时期我国公民意识教育的理性思考

为实现全面建成小康社会的奋斗目标,坚持中国特色社会主义政治建设是一个重要内容,而发展社会主义民主政治建设又需要一个坚实的社会基础,这就是一个普遍民众都具有较强公民意识的现代社会。文章在对公民和公民意识进行阐述的基础上,分析了当前我国民众公民意识教育的重要性,及加强公民意识教育的有效途径。     

非正交面齿轮副动力学仿真分析

目的:探究非正交面齿轮与直齿圆柱齿轮组成的齿轮副在啮合传动过程中动力学特性,为基于面齿轮的传动装置提供动力学仿真分析参考.方法:首先根据啮合原理,利用包络法推导非正交面齿轮齿面的曲面族,再通过VS编写相应的计算程序,计算得到非正交面齿轮齿面上的有限个坐标点,然后使用catia曲面设计程序,得到非正交面齿轮模型,最后将非正交面齿轮与配对圆柱齿轮进行正确装配,使用动力学分析软件Adams进行啮合仿真分析.结果:通过对比分析表明,动力学仿真分析下的非正交面齿轮输出转速、法向载荷、圆周力、径向力和轴向力与理论计算基本一致.结论:验证了非正交面齿轮在啮合传动过程中有轴向力的产生,面齿轮传动具有周期性啮入啮出的特性.     

Bilingualism and morphological awareness: a study with children from general education and Spanish-English dual language programs

Existing research on the impact of bilingualism on metalinguistic development has concentrated on the development of phonological awareness. The present study extended the scope of existing research by focusing on morphological awareness, an aspect of metalinguistic awareness that becomes increasingly important beyond the initial phase of literacy development. Participants included three groups of fourth-grader children from the same school with comparable SES and non-verbal IQ: (a) monolingual English-speaking children from a general education programme, (b) Spanish-speaking children from a Spanish–English dual-language programme and (c) English-speaking children from the same Spanish–English dual-language programme. Researcher-developed measures of vocabulary and morphological awareness were administered. Results suggested that bilingual education can have a positive impact on the development of morphological awareness through cross-language transfer as well as increased sensitivity to structural language features. The findings contribute to a growing body of research on how bilingual experience may shape children’s metalinguistic development.     

Cross-document event clustering using knowledge mining from co-reference chains

Unifying terminology usages which captures more term semantics is useful for event clustering. This paper proposes a metric of normalized chain edit distance to mine, incrementally, controlled vocabulary from cross-document co-reference chains. Controlled vocabulary is employed to unify terms among different co-reference chains. A novel threshold model that incorporates both time decay function and spanning window uses the controlled vocabulary for event clustering on streaming news. Under correct co-reference chains, the proposed system has a 15.97% performance increase compared to the baseline system, and a 5.93% performance increase compared to the system without introducing controlled vocabulary. Furthermore, a Chinese co-reference resolution system with a chain filtering mechanism is used to experiment on the robustness of the proposed event clustering system. The clustering system using noisy co-reference chains still achieves a 10.55% performance increase compared to the baseline system. The above shows that our approach is promising.     

Responses of endothelial cells to extremely slow flows

The process of blood vessel formation is accompanied by very minimal flow in the beginning, followed by increased flow rates once the vessel develops sufficiently. Many studies have been performed for endothelial cells at shear stress levels of 0.1-60 dyn∕cm(2); however, little is known about the effect of extremely slow flows (shear stress levels of 10(-4)-10(-2) dyn∕cm(2)) that endothelial cells may experience during early blood vessel formation where flow-sensing by indirect mass transport sensing rather than through mechanoreceptor sensing mechanisms would become more important. Here, we show that extremely low flows enhance proliferation, adherens junction protein localization, and nitric oxide secretion of endothelial cells, but do not induce actin filament reorganization. The responses of endothelial cells in different flow microenvironments need more attention because increasing evidence shows that endothelial cell behaviors at the extremely slow flow regimes cannot be linearly extrapolated from observations at faster flow rates. The devices and methods described here provide a useful platform for such studies.