The Jatropha biofuels sector in Tanzania 2005-2009: Evolution towards sustainability?

Biofuel production has recently attracted much attention. Some anticipate substantial social and environmental benefits, while at the same time expecting sound profitability for investors. Others are doubtful, envisaging large trade-offs between the pursuit of social, environmental and economic objectives, particularly in poor countries in the tropics. The paper explores these issues in Tanzania, which has been an African forerunner in the cultivation of a bio-oil shrub called Jatropha curcas L. We trace how isolated Jatropha biofuel experiments developed since early 2005 towards a sectoral production and innovation system, and we investigate to what extent that system has been capable of developing and maintaining sustainable practices and producing sustainable outcomes. The application of evolutionary innovation theory allows us to view the developments in the sector as a result of evolutionary variation and selection on the one hand, and revolutionary contestation between different coalitions of stakeholders on the other. Both these processes constitute significant engines of change. While variation and selection are driven predominantly by localised technical and agronomic learning, the conflict-driven dynamics are highly globalised and occur primarily as a result of reflexive learning about problematic sustainability impacts. The sector is found to have moved some way towards a full sectoral innovation and production system, but it is impossible to predict whether a viable sector with a strong “triple bottom line” orientation will ultimate emerge, since many issues surrounding the social, environmental and financial sustainability still remain unresolved, especially relating to local and global governance.     

How medical practice evolves: Learning to treat failing hearts with an implantable device

In this article we propose that medical practice evolves as a result of progress along three different pathways: improvement in the ability to develop effective medical technologies, learning in medical practice, and advances in biomedical scientific understanding of disease. The relative importance of these three pathways varies from case to case, and often they interact strongly. More specifically, we argue here that in cases of therapeutic innovation where a new medical technology is involved the advance in medical practice is driven largely by the ability to develop and use effective medical artifacts and the interactive sequence among these interdependent pathways often starts with what is learned in practice and not in science. While we state this argument in general, we develop it in detail in a longitudinal and contextual case study of the emergence and evolution of a treatment for advanced heart failure based on an implantable device, the Left Ventricular Assist Device (LVAD). Our findings show that an essential aspect of the evolution of the LVAD therapy is collective and cumulative learning that requires experience that only can be gained through the actual use of LVADs. We discuss the theoretical and policy implications that follow from our understanding of how medical practice evolves for research on the evolution of medical practices and new medical technologies, and policies about the evaluation of rapidly moving medical practices and clinical research involved in their advancement.     

新形势下高职院校学生干部队伍建设的研究

高职院校学生干部是学校开展各项学生工作的桥梁和纽带,在社会经济转型的新形势下如何建设一支学生拥护、教师信赖、梯队合理的学生干部队伍,是当前高职院校学生工作者必须面临的问题。本文从新形势下高职院校学生干部队伍现状及其问题解析入手,结合工作实践,在建构主义理论的指导下探索高职院校学生干部队伍建设的对策。     

成人学习动机研究简述

本文对成人学习动机的概念、意义、近年来研究的概况、研究特点、热点问题分析等进行了简述。     

基于K-means和Label Propagation的半监督网页分类

提出基于图的半监督学习算法,即类别传播算,结合K均值算法改进,用于网页分类。该K均值类别传播方法使用欧式距离的建立带权∈NN图。在这个图中,图节点表示已标记或未标记的网页,边上的权重表示节点的相似度,已标记节点的类别沿着边向邻居节点传播,从而将网页分类问题形式化为类别在图上的传播。结合K均值方法,提高了计算速度以及图方法的归纳能力,经UCI数据集测试,结果表明,此算法比类别传播算法有更好的性能,能够有效地用于半监督网页分类。     

基于Web2.0的学习

对基于Web 2.0的学习进行了论述。通过分析Web 2.0的模式和特征,探讨了Web 2.0在教学过程中对于教师和学习者产生的新的教学、学习方式,考察了Web 2.0对于学习资源进行的知识管理,提出了在Web 2.0学习中对学习者生存能力和道德规范的要求。     

基于数字化博物馆的研究性学习及其设计案例

数字化博物馆综合了网络、多媒体的优势和实体博物馆的功能,为非正式学习和终身教育的开展提供了有效支持。从研究性学习与数字化博物馆的基本概念入手,以Webquest模式为例,分析了基于数字化博物馆的研究性学习及其存在问题,在介绍国外案例的基础上,设计了一个基于数字化博物馆的研究性学习活动。     

网络学习中网瘾大学生的学习现状分析

目前,大学生网络成瘾占比非常高。通过对网络学习课堂的观察,发现网瘾大学生在网络学习中的问题,并探究解决的对策。     

PBL教学模式在Flash动画设计课程中的实践探索

通过PBL教学模式在《Flash动画设计》教学过程中的应用,发现PBL教学法能激发学生兴趣,提高学生独立分析、解决问题及自主学习的能力,同时也有助于塑造学生在动画设计制作过程中的创意设计能力。     

数字图像处理课程教学方法研究

本文针对数字图像处理课程章节多、算法复杂、学科跨度大、知识体系庞大的特点,提出了基于内容关联性的课时规划方法、基于权重的算法学习法、基于期望目标的仿真软件选择法以及关键问题多角度诠释的方法来提升教学及学习效果。实践表明,这些教学方法的实施对数字图像处理课程教学具有良好的效果和积极的现实意义。