Preservice elementary teachers’ knowledge for teaching the associative property of multiplication: A preliminary analysis

This study examines preservice elementary teachers’ (PTs) knowledge for teaching the associative property (AP) of multiplication. Results reveal that PTs hold a common misconception between the AP and commutative property (CP). Most PTs in our sample were unable to use concrete contexts (e.g., pictorial representations and word problems) to illustrate AP of multiplication conceptually, particularly due to a fragile understanding of the meaning of multiplication. The study also revealed that the textbooks used by PTs at both the university and elementary levels do not provide conceptual support for teaching AP of multiplication. Implications of findings are discussed.     

武汉市某高校大学生健康素养现状调查

为了了解大学生的健康素养水平,为开展健康教育及健康促进工作提供参考依据.本研究选取武汉市某高校2010级在读本科生300名,以《中国公民健康素养——基本知识与技能》为基础,采用问卷调查方法,并使用Microsoft excel建立数据库进行数据分析.结果显示了受调查的大学生对健康知识的平均知晓率为70.48%,对于健康生活方式与行为的平均熟悉程度为64.93%,以及求生技能的平均掌握率为92.67%.该调查结果表明了该校大学生对于健康基本技能的掌握较好,对于健康知识和理念有一定了解,但在健康概念、健康知识与行为等方面均存在较多不足,因此,大学生的健康素养仍有待加强.     

知识体系与认知规律相结合建设分析化学课程教材

阐述教材是提高教学质量重要且必备的条件之一,回顾我国分析化学工作者编写教材的实践历程,提出编写教材应体现＂注重学科基础、关注学科前沿、适当拓展学科交叉,体现知识体系与认知规律相结合＂的特点。     

A comparison of parallel large-scale knowledge acquisition using rough set theory on different MapReduce runtime systems

Nowadays, with the volume of data growing at an unprecedented rate, large-scale data mining and knowledge discovery have become a new challenge. Rough set theory for knowledge acquisition has been successfully applied in data mining. The recently introduced MapReduce technique has received much attention from both scientific community and industry for its applicability in big data analysis. To mine knowledge from big data, we present parallel large-scale rough set based methods for knowledge acquisition using MapReduce in this paper. We implemented them on several representative MapReduce runtime systems: Hadoop, Phoenix and Twister. Performance comparisons on these runtime systems are reported in this paper. The experimental results show that (1) The computational time is mostly minimum on Twister while employing the same cores; (2) Hadoop has the best speedup for larger data sets; (3) Phoenix has the best speedup for smaller data sets. The excellent speedups also demonstrate that the proposed parallel methods can effectively process very large data on different runtime systems. Pitfalls and advantages of these runtime systems are also illustrated through our experiments, which are helpful for users to decide which runtime system should be used in their applications.     

维也纳应用科技大学ENERGYbase大楼简析——奥地利首个绿色生态示范办公建筑

通过欧亚太平洋大学联盟国际合作研究项目,对奥地利首个绿色生态示范办公建筑一维也纳ENERGYbase大楼设计理念、可再生能源的利用方式、生态技术设计手段进行了介绍,以使国内建筑师对欧洲生态节能建筑有一个全面的了解．     

Stability of Hoogsteen‐Type Triplexes – Electrostatic Attraction between Duplex Backbone and Triplex‐Forming Oligonucleotide (TFO) Using an Intercalating Conjugate

Syntheses are described for two novel twisted intercalating nucleic acid (TINA) monomers where the intercalator comprises a benzene ring linked to a naphthalimide moiety via an ethynediyl bridge. The intercalators Y and Z have a 2‐(dimethylamino)ethyl and a methyl residue on the naphthalimide moiety, respectively. When used as triplex‐forming oligonucleotides (TFOs), the novel naphthalimide TINAs show extraordinary high thermal stability in Hoogsteen‐type triplexes and duplexes with high discrimination of mismatch strands. DNA Strands containing the intercalator Y show higher thermal triplex stability than DNA strands containing the intercalator Z . This observation can be explained by the ionic interaction of the protonated dimethylamino group under physiological conditions, targeting the negatively charged phosphate backbone of the duplex. This interaction leads to an extra binding mode between the TFO and the duplex, in agreement with molecular‐modeling studies. We believe that this is the first example of an intercalator linking the TFO to the phosphate backbone of the duplex by an ionic interaction, which is a promising tool to achieve a higher triplex stability.     

粗糙集理论及其应用研究

粗糙集理论是一种新型的处理模糊和不确定知识的数学工具。本文给出了粗糙集理论的特点,阐述了几种粗糙集理论的扩展模型及其应用领域,最后讨论了粗糙集理论研究的前景。     

井冈山革命根据地政权建设的经验教训及现实启示

在井冈山革命根据地政权建设中所积累的成功经验和留下的深刻教训,为后来的中国革命提供了借鉴,对当前加强党的执政能力建设,构建社会主义和谐社会仍具有指导意义。     

德摩根一致代数可度量化的一个充要条件

讨论德摩根代数上的拟一致结构与度量之间的联系，给出德摩根一致代数可伪度量化的一个充分必要条件，所有结论均包含经典拓扑和模糊拓扑中的相应结果作为特例。     

LTE-A异构网络中一种向下垂直切换预判决算法

大量而频繁的不必要切换问题是限制家庭基站应用的一个重要原因。为了降低宏基站与家庭基站之间的不必要切换率,提出了一种向下垂直切换预判决算法;该算法对低速用户仍采用传统的基于接收信号强度的切换判决算法;而对高速用户设置有效驻留时间门限。在保证用户信干噪比的前提下,拒绝有效驻留时间低于门限值的切换请求。仿真结果表明,所提出的切换预判决算法在有效降低基站间不必要切换率的同时,显著地降低了用户的中断概率。