Social Cognitive Factors,Support, and Engagement: Early Adolescents’ Math Interests as Precursors to Choice of Career

The authors examined the central hypothesis that students’ early perceptions of support and sense of engagement in math classes and math activities strongly influence the broadening or narrowing of their math interest. The focus was on the first wave of qualitative data collected from 5th‐, 7th‐, and 9th‐grade students during the 2007–2008 academic year as part of a longitudinal study. Findings indicate the importance of using group work and extrinsic motivation in middle school math classes to broaden interest; peer classroom behavior was often a detractor of math interest.     

Points System:An Universal Beneficial System with Multiple Objectives of Reform on Household Registration System

Reform of China's Household Registration system(HRS) has been entering a new stage and deserves us to research.The paper argues that reform of HRS should have multiple objectives.It examines various local efforts and practices of the reform and claims that the point system is one of the most feasible alternative systems for the HRS that can fit those multiple reform objectives.The system could also be treated as the new institutional basic for public welfare provision and rights allocation,and a new governance means for population issues as well in China's transitional period.     

Exclusion and vulnerability on public transit: experiences of transit dependent riders in Portland,Oregon

In urban areas, the inequitable distribution of transit systems and services has been shown to reproduce safety and environmental risks – potentially exacerbating preexisting inequities. Thus, how vulnerable populations access and utilize public transportation is of critical concern to urban scholars. This paper utilizes focus group data to explore how transit-dependent (particularly low-income) riders engage with the public transit system in Portland, Oregon. We illustrate specific ways in which transit-dependent riders experience marginalization and exclusion. We find that certain groups, particularly mothers with young children and those with disabilities are not well served by a public infrastructure oriented toward an ‘ideal rider’ who is an economically stable, able-bodied, white, male commuter. We conclude that a public infrastructure meant to serve all riders equitably, yet which fails to consider the unique experiences of marginalized transit users risks further amplifying existing social vulnerabilities and reinforcing gender, racial, and class inequalities.     

Conditional entropy,entropy density,and strong law of large numbers for generalized controlled tree-indexed Markov chains

In this paper, we first introduces a tree model without degree boundedness restriction namely generalized controlled tree T, which is an extension of some known tree models, such as homogeneous tree model, uniformly bounded degree tree model, controlled tree model, etc. Then some limit properties including strong law of large numbers for generalized controlled tree-indexed non homogeneous Markov chain are obtained. Finally, we establish some entropy density properties, monotonicity of conditional entropy, and entropy properties for generalized controlled tree-indexed Markov chains.     

Uniform Test for Predictive Regression With AR Errors

Testing predictability is of importance in economics and finance. Based on a predictive regression model with independent and identically distributed errors, some uniform tests have been proposed in the literature without distinguishing whether the predicting variable is stationary or nearly integrated. In this article, we extend the empirical likelihood methods of Zhu, Cai, and Peng with independent errors to the case of an AR error process. Again, the proposed new tests do not need to know whether the predicting variable is stationary or nearly integrated, and whether it has a finite variance or an infinite variance. A simulation study shows the new methodologies perform well in finite sample.     

历史理性与历史感

在史学实践的范围内,历史理性可以理解为人们在把握过去时的精神结构和智力装备,历史感是其中不可或缺的要素。对于人事变易无常的意识、对于过去与现在之间的异同的敏锐感受、健全的历史观、开放而自我克制的历史想象力、微观研究与宏观视野的结合,都是历史感在史家史学实践中的具体体现。分析学派的和叙事主义的史学理论都未能将历史感纳入自身的研究焦点。史学理论的当前转向为历史理性和历史感得到更为清晰的理论阐发提供了契机。     

宋代笔记与诗词关系探论

宋代文学的翘楚是文言散文,笔记又属散文中的大宗.梳理宋人笔记与其诗词作品之间的关系,有助于客观全面把握宋人诗文创作、理论批评的特点,避免因局限于一类一体的考察,而忽视对作家的整体性观照.爬梳大量现存宋代笔记和代表性文士的诗词创作情况,探析诗话与词话生成演进的文学史历程,剖判诗词与笔记文类交涉的概貌,可以发现,笔记是诗词作品文本的渊薮,能够据此校勘异文,勾稽本事,作为文献之宝库;更进一步,笔记也与诗词批评专著的生成交涉甚深,诗话、词话的成立,实源于笔记的孳乳,是笔记诞育了这一从著述体式到内容题材都极富中国文学批评特色的典型形式;另外,"以笔记为诗""诗化笔记",彰显出二者文体互渗的审美取径.     

动态视角下中国城市群土地利用TFP测度及影响因素研究

提高城市群土地利用TFP对合理高效利用土地资源,协调好城市群经济发展、资源配置和环境保护具有重大理论和实践意义.文章运用DEA-Malmquist指数对2003—2016年动态视角下中国城市群土地利用TFP进行测度和时空演变分析,并利用Tobit回归模型对影响城市群土地利用TFP变化的因素进行深入研究.结果表明:从时间维度看,城市群土地利用TFP年均上升0.7％,城市群土地利用TFP增长由技术效率和技术进步"双核驱动",技术效率的提升主要与纯技术效率提升有关,规模效率是技术效率和土地利用TFP提升的瓶颈约束;从空间维度看,晋中、哈长、海峡西岸、中原、长江中游、北部湾、成渝、黔中、关中平原和兰西城市群土地利用TFP呈下降趋势,其余城市群土地利用TFP均呈上升趋势,且京津冀、呼包鄂榆、辽中南、长江三角洲、山东半岛和天山北坡城市群土地利用TFP增长为技术进步和技术效率"双核驱动";从影响因素看,人均GDP和年末金融机构人民币各项贷款余额对中国城市群土地利用TFP具有正向促进作用,城市财政支出占本市GDP的比重和人口密度具有负向阻碍作用.     

汽车侧围外板尾翼拉延成型工艺改善研究

为解决汽车侧围外板尾翼在拉延成型后出现起皱和开裂的问题，设计了3种造型方案.通过造型设计分析及Autoform模拟，对比3种方案，对原工艺进行整改和优化，得到了抬高造型台阶面的最优造型方案.该方案能改善进料速度、增加材料流动性，有效地消除开裂、起皱的缺陷，对同类和其他类似产品的冲压工艺设计具有参考意义.