Elementary school students’ naïve conceptions and misconceptions about energy in physical education context

The purpose of this study was to explore and reveal naïve conceptions and misconceptions about energy embedded in elementary school students’ prior knowledge. Students’ performance on standardized knowledge test was used to classify students into low, median and high levels of knowledge about the cardiovascular system. Semi-structured in-depth interviews were conducted with students in each group to extract their understanding of energy in relation to food choices, physical activities, and exercises. Analysis of the interview data generated six categories of naïve conceptions and two categories of misconceptions. Different conceptual change theories, including Chi’s ontological change theory, Ohlsson’s resubsumption theory, and enculturation theory were used to analyze and understand these naïve conceptions and misconceptions and why they could be robust to change. The analyses confirm the need to adopt a multi-theoretical approach to the understanding of students’ naïve conceptions and misconceptions (Chinn & Samarapungavan, 2009. Conceptual change-multiple routes, multiple mechanisms: A commentary on Ohlsson. Educational Psychologist, 44(1), 1–10). The findings encourage physical and health educators adopt different strategies to address the potential learning obstacles brought by students’ naïve conceptions and misconceptions.     

生物措施防治土壤盐渍化的机理及研究进展

干旱、半干旱灌区土壤的次生盐渍化已严重影响农业的可持续发展和当地及周边地区的生态环境.本文简要介绍了国内外盐渍土的分布状况,次生盐渍土形成缘由和各种治理措施的优势和存在的问题;详细阐述了生物措施治理土壤次生盐渍化的机理,即灌水在盐渍地脱盐中起主导作用,茂密的植物地上冠层减缓了土壤的积盐速度,植物吸收的土壤盐分随着收获而被移除,植物地下根系改善了土壤的理化、生物学性质,有利于土壤的脱盐和减弱土壤的盐碱性;最后,简要回顾了国内利用生物措施治理盐渍化的研究现状和存在的问题,并提出今后的研究方向(豆禾混播防治土壤退化).     

Is in-class physical activity at risk in constructivist physical education?

Constructivist physical education emphasizes cognitive engagement. This study examined the impact of a constructivist curriculum on in-class physical activity. Caloric expenditure in metabolic equivalents (MET) and vector magnitude count (VM) data from a random sample of 41 constructivist lessons were compared with those from a random sample of 35 nonconstructivist lessons. Statistical analyses revealed that students in both curriculum conditions were active at a similarly low-moderate level (MET = 2.6 for experimental, 2.5 for comparison, p = .30). Differences (p < .05) were found between the three units within the constructivist curriculum. The findings suggest that the constructivist approach may facilitate knowledge learning with little risk of reducing in-class physical activity.     

Exploring coherent topics by topic modeling with term weighting

Topic models often produce unexplainable topics that are filled with noisy words. The reason is that words in topic modeling have equal weights. High frequency words dominate the top topic word lists, but most of them are meaningless words, e.g., domain-specific stopwords. To address this issue, in this paper we aim to investigate how to weight words, and then develop a straightforward but effective term weighting scheme, namely entropy weighting (EW). The proposed EW scheme is based on conditional entropy measured by word co-occurrences. Compared with existing term weighting schemes, the highlight of EW is that it can automatically reward informative words. For more robust word weight, we further suggest a combination form of EW (CEW) with two existing weighting schemes. Basically, our CEW assigns meaningless words lower weights and informative words higher weights, leading to more coherent topics during topic modeling inference. We apply CEW to Dirichlet multinomial mixture and latent Dirichlet allocation, and evaluate it by topic quality, document clustering and classification tasks on 8 real world data sets. Experimental results show that weighting words can effectively improve the topic modeling performance over both short texts and normal long texts. More importantly, the proposed CEW significantly outperforms the existing term weighting schemes, since it further considers which words are informative.     

图书馆、档案馆和博物馆三馆馆际资源共享态度的调查与分析

公共文化信息资源的整合利用是促进全社会信息资源共建共享的重要组织部分。以图书馆、档案馆和博物馆馆员为研究对象,对他们的馆际资源共享态度进行问卷调查,建议促进三馆数字资源的活跃性和关联性、资源共享平台的标准化和开放性,达到合作开发和保护地方文化遗产的目的。     

Interdisciplinary dialogues as a site for reflexive exploration of conceptual understandings of teaching–learning relationships

This study examines what the members of an interdisciplinary research alliance, at the intersection of Engineering and Education Ethnography, learned through ongoing dialogues among members (2012–2014). The analyses make visible how, and for what purpose(s), this interdisciplinary research alliance was constructed, including the theoretical/conceptual roots of perspectives guiding the members of the alliance, and how these orienting perspectives served as anchors for exploring points where differences in understandings became visible to members. By tracing responses that members had to differences in understandings, we examine how the differences became resources for members to (re)examine their initial assumptions and understandings of particular teaching–learning processes, and how these differences supported members, individually and collectively, in extending and (re)formulating their understandings of the relationship between and among teaching and learning processes that constituted no distance education processes. Through the presentation of three telling cases, we make visible how the dialogues led to different levels of ethnographic analysis (cases 1 and 2). Each was undertaken to develop an understanding of what counted as the no distance education process, both at the design and institutional level across national institutions as well as in the course across times and events. The third telling case explores transformations in understanding particular aspects of teaching–learning relationships that the members reported were related to the ongoing dialogues and ethnographic research.     

基于育人视域的校园绿化与环境优化策略——以湖南第一师范学院新校区为例

高校的根本任务是育人,校园环境对大学生成长、成才有着至关重要的作用。湖南第一师范学院新校区校园建设的实践不仅体现出校园绿化美化基本功能,而且也为校园环境优化育人的设计策略提供了参考。     

微博用户的抑郁和焦虑预测

临床心理学指出,心理健康状况通过人的行为表现,其中包括网络行为.传统的心理健康测评以自陈量表的形式为主.这不但要耗费大量的人工处理工作,更不能做到实时进行心理健康状态的获取.针对传统方法的不足,本文旨在通过新浪微博的环境,预测用户的心理健康状况,特别是抑郁和焦虑问题.通过批量获取微博用户的网上数据,验证了传统理论中人格和心理健康之间的相关性,并采用多任务回归学习预测微博用户的心理健康状况.结果表明,心理健康问题可以通过网络行为反映出来,通过用户的微博使用情况,预测其抑郁和焦虑的程度是可行的.     

浅谈产品生命周期理论在营销管理中的应用

国外一些大企业利用产品生命周期理论PLC成功地延长了产品的生命周期,使企业稳定经营几十年乃至上百年。而许多国内企业的产品生命周期却只有6-8年。根据生命周期理论、如何判断产品所处的生命周期阶段,着重从市场营销角度研究如何进行产品生命周期管理,旨在对延长国内企业的产品生命周期提供借鉴经验。     

网球CAI课件的设计和研制

随着计算机技术的飞速发展，把多媒体技术引入网球教学过程中已经成为现实。中阐述了开发网球CAI系统的必要性，重点介绍该课件的制作过程和实现过程，以及对教师和学生的影响。