Modeling the developmental trajectories of rational number concept(s)     

《Learning and Instruction》2015

The present study focuses on the development of two sub-concepts necessary for a complete mathematical understanding of rational numbers, a) representations of the magnitudes of rational numbers and b) the density of rational numbers. While difficulties with rational number concepts have been seen in students' of all ages, including educated adults, little is known about the developmental trajectories of the separate sub-concepts. We measured 10- to 12-year-old students' conceptual knowledge of rational numbers at three time points over a one-year period and estimated models of their conceptual knowledge using latent variable mixture models. Knowledge of magnitude representations is necessary, but not sufficient, for knowledge of density concepts. A Latent Transition Analysis indicated that few students displayed sustained understanding of rational numbers, particularly concepts of density. Results confirm difficulties with rational number conceptual change and suggest that latent variable mixture models can be useful in documenting these processes.  相似文献   

Interactions between Niche and Regime: An Analysis of Learning and Innovation Networks for Sustainable Agriculture across Europe     

Julie Ingram  Damian Maye  James Kirwan  Nigel Curry  Katarina Kubinakova 《The Journal of Agricultural Education and Extension》2015,21(1):55-71

Abstract

Purpose: This paper aims to reveal, and contribute to an understanding of, the processes that connect learning and innovation networks in sustainable agriculture to elements of the mainstream agricultural regime. Drawing on the innovations and transition literature, the paper frames the analysis around niche-regime interaction using the notion of niche-regime compatibility.

Design/Methodology/Approach: 17 Learning and Innovation Networks for Sustainable Agriculture (LINSA) engaged in agricultural food production, non-food and rural development were analyzed. In line with the project's transdisciplinary approach data were collected in a series of participatory workshops.

Findings: Five modes of LINSA-regime interaction are distinguished based on compatibility. The level of LINSA-regime compatibility influences the extent of the diffusion of LINSA ideas and practices into the regime. However, interaction processes within these modes reveal multiple and diverse connections between LINSA and regime entities suggesting a more complex relationship exists.

Practical implications: A range of connecting processes and activities (for example, certification, exemption from regulation, facilitation of networking) can bring about effective LINSA-regime interaction and could be externally supported.

Originality/Value: Empirical evidence from 17 case studies provides valuable insights from a number of different contexts across Europe. By directing analysis of interaction at the level of LINSA (niche project), rather than at the macro level, the study offers an original perspective. It suggests that the transition to sustainable agriculture might be understood as a complex of interactive processes leading to a series of adaptive changes, rather than as regime change.  相似文献   

基于ATML标准的测试流程表示方法研究     

王斯侠  高艳华  张永全  周华光 《人天科学研究》2014,(8):18-22

测试信息标准化描述是实现不同ATS平台之间数据交换的关键。针对地面测控设备种类多样及自动测试系统测试任务复杂的情况,对ATML标准进行了深入研究。分析了ATML标准族的背景、目的、模型结构及组件标准,说明了仪器和测试结果组件在实际应用中的信息描述方法,并结合有限自动机的状态转换图理论,提出了测试流程状态转换图模型。实验中设计了一种测试流程信息标准化描述方法,解决了自动测试系统中的数据交换及信息共享问题。实验结果表明ATML在自动测试领域具有良好的发展前景。  相似文献   

竞技武术套路运动员转项成才个案研究     

梁闻铭 《搏击·武术科学》2014,11(12):48-49

文章主要运用深度访谈法,通过以2009年空手道世界锦标赛个人型项目季军黄少青为访谈对象进行个案研究,对竞技武术套路运动员成功转项为空手道个人型项目运动员并获得优异成绩的现象进行初步的探究与分析。结论认为：竞技武术套路运动员转为空手道个人型项目运动员有很大的优势,也存在困难;通过转项后的刻苦训练成才的希望大,且成才年限较短;转项之初的心理压力要及时调整。  相似文献   

基于隧道技术和NAT-PT结合的IPv6网络     

陈萌  夏昕 《科技广场》2006,(11):53-54

本文在深入研究由因特网工程任务组(IETF)提出的从IPv4到IPv6过渡的3种机制(NAT—PT、隧道、双栈)的基础上,分别给出了NAT—PT和隧道的具体实现技术,并提出利用这两种技术的协同工作如何来组建IPv6网络,最后通过对具体案例的分析,显示其技术优势。  相似文献   

Socio-political factors and the failure of innovation policy in Croatia as a country in transition     

Jadranka Švarc 《Research Policy》2006,35(1):144-159

This paper discusses the roles of socio-political factors and related public policies in the economic growth of Croatia, as well as their influence on its transition to a knowledge economy (KE). The Croatian experience might help to understand transition processes in other Central and Eastern European Countries (CEECs). This paper argues that Croatia has failed to capitalize on its inherited science base, which could have been used as a starting point in the transition towards a KE, because it has not made the shift from an obsolete socialist-style science policy to a modern innovation policy (IP); the latter is seen as the new policy paradigm necessary for structural adjustment to a KE.Covert socio-political growth factors shaped by the country-specific historical heritage of Croatia have prevented the recognition of the need for structural adjustment to the new technology regime, and have led to the belief that the IP is not only irrelevant but is also a relict of the state interventionism inherited from socialism, which was the most serious obstacle to policy reform.Examples drawn from the development of the IP and the National System of Innovation (NSI) in Croatia, which shares the socialist model of science policy and the socio-political context of the transition towards a market economy with other CEECs, can help to explain the failure of the IP. In the Croatian case, the decisive factors were the social state of so-called “semi-modernism” and the governance of the so-called “de-industrializing elite”.This paper concludes that the transition of a CEEC from a market economy to a KE requires a serious re-design of development policy, the effectiveness of which depends on social change determined by the political recognition and social assimilation of the new technological regime. In this sense, the current paper contributes to the understanding of the roles of social capital and governance in the economic growth of post-socialist countries.  相似文献   

浅谈下一代互联网协议IPv6     

张文丽 《科技广场》2007,(3):242-244

随着Internet的飞速发展,IPv4的缺陷逐渐凸现。针对这个问题,文章介绍了IPv6产生的背景以及IPv6的新特性,同时阐述了从现有的IPv4网络过渡到IPv6的策略。  相似文献   

Transition to formal schooling: Do transition practices matter for academic performance?     

Annarilla Ahtola  Gintautas SilinskasPirjo-Liisa Poikonen  Marita KontoniemiPekka Niemi  Jari-Erik Nurmi 《Early childhood research quarterly》2011,26(3):295

This study examined whether the transition practices implemented in preschool-elementary school pairs contribute to children's academic development during the first year of elementary school. Participants were 398 children who moved from 36 preschools to 22 elementary schools in two Finnish towns. Children were tested in respect to their reading, writing, and math skills in the preschool spring and in the grade 1 spring. The most common practices reported by preschool teachers were discussions about the school entrants and familiarizing preschool children with the school environment and the new teacher. Multilevel latent growth modeling showed that the more the preschool teachers and elementary-school teachers implemented various supportive activities during the preschool year, the faster the children's skills developed from preschool to grade 1 spring. Co-operation over curricula and passing on written information about children between the preschool and the elementary school were the best predictors of the children's skills, although they were the least commonly used practices. The need to restructure the transition to elementary school and the use of multiprofessional resources are discussed.  相似文献   

传媒体制、媒体社会责任与公共利益——基于美国广播电视体制变迁的反思   总被引：4，自引：0，他引：4  

张春华 《国际新闻界》2011,(3)

本文在梳理美国广播电视体制历史变迁的基础上,分析公共利益在不同的规制模式下的差异化呈现,剖析公共利益与传媒体制之间的关系,进而探究商业化运作背景下实现和确保公共利益的有效路径。  相似文献   

新媒介生态下的香港报业转型研究     

刘晓燕 《国际新闻界》2011,(5)

在互联网引发的新媒介生态下,香港报业呈现出两种转型模式:一是以星岛新闻集团为代表的免费内容与规模效益模式:免费报通过对收费报新闻的再加工,降低采编成本,实现规模效益。二是以壹传媒有限公司为代表的产品深加工与免费增值模式:大部分新闻产品实行免费以增加人气,少部分深加工的新媒体内容微收费,以实现盈利。香港报业转型中遭遇的最根本的困境在于,高成本生产的新媒体产品难以盈利。免费成为新媒介生态下唯一的内容生存之道。  相似文献