Bridge pressure flow scour at clear water threshold condition     

郭俊克 《天津大学学报(英文版)》2009,15(2):79-94

Bridge pressure flow scour at clear water threshold condition is studied theoretically and experimentally. The flume experiments reveal that the measured scour profiles under a bridge are more or less 2-dimensional; all the measured scour profiles can be described by two similarity equations, where the horizontal distance is scaled by the deck width while the local scour by the maximum scour depth; the maximum scour position is located just under the bridge about 15% deck width from the downstream deck edge; the scour begins at about one deck width upstream the bridge while the deposition occurs at about 2.5 deck widths downstream the bridge; and the maximum scour depth decreases with increas-ing sediment size, but increases with deck inundation. The theoretical analysis shows that: bridge scour can be divided into three cases, i.e. downstream unsubmerged, partially submerged, and totally submerged. For downstream unsubmerged flows, the maximum bridge scour depth is an open-channel problem where the conventional methods in terms of critical velocity or bed shear stress can be applied; for partially and totally submerged flows, the equilibrium maximum scour depth can be described by a scour and an inundation similarity number, which has been confirmed by experiments with two decks and two sediment sizes. For application, a design and field evaluation procedure with examples is presented, including the maximum scour depth and scour profile.  相似文献   

Learning Diversity in the Chinese Classroom: Contents and practice for students with special needs     

Li‐Yu Hung 《International Journal of Disability, Development & Education》2009,56(3):310-312

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Peeling Back the Layers of Policy and School Reform: Revealing the structural and social complexities within     

Haley Woodside‐Jiron  Kristin M. Gehsmann 《International Journal of Disability, Development & Education》2009,56(1):49-72

This article explores the complex process of school change over a six‐year period in one high‐poverty, urban elementary school in a northeastern city of the United States. The school included in this instrumental case study was identified by its State Department of Education as “being in need of improvement” in March 2000. Findings suggest that creating opportunities for context‐based solutions, curricular coherence, and responsive and consistent coaching were the necessary means for leveraging change at this school. Further, responding to the layers and iterations of educational policy, and addressing the deeper social issues intimately associated with serving high‐poverty communities, was essential. We identify policy issues that contributed to the complexity of this school’s improvement efforts. Our analysis extends beyond surface‐level documentation of the school’s inputs and outputs, and illustrates what it means to meet individual students’ needs in complex social and institutional spaces. We also discuss social justice issues that are linked with current policies targeting improved outcomes for all children.  相似文献   

IQ and neuropsychological predictors of academic achievement     

Susan Dickerson Mayes  Susan L. Calhoun  Edward O. Bixler  Dennis N. Zimmerman 《Learning and individual differences》2009,19(2):238-241

Word reading and math computation scores were predicted from Wechsler Abbreviated Scale of Intelligence Full Scale IQ, 10 neuropsychological tests, and parent attention deficit hyperactivity disorder (ADHD) ratings in 214 general population elementary school children. IQ was the best single predictor of achievement. In addition, Digit Span contributed significantly to reading prediction, and the Developmental Test of Visual-Motor Integration (VMI) and Coding contributed to math prediction. The remaining neuropsychological test scores did not significantly improve achievement prediction. Exploratory factor analysis yielded a general ability factor (comprising the four IQ subtests, Digit Span, VMI, reading, and math), five factors made up solely of subtests from single measures (Wisconsin Card Sorting Test, Stroop Color and Word Test, Gordon Diagnostic System, California Verbal Learning Test, and ADHD ratings), a factor consisting of Grooved Pegboard Test and Coding, and a factor consisting of Symbol Search and Animal Naming Test.  相似文献   

Variation in Raven's Progressive Matrices scores across time and place     

Symen A. Brouwers  Fons J.R. Van de Vijver  Dianne A. Van Hemert 《Learning and individual differences》2009,19(3):330-338

The paper describes a cross-cultural and historical meta-analysis of Raven's Progressive Matrices. Data were analyzed of 798 samples from 45 countries (N = 244,316), which were published between 1944 and 2003. Country-level indicators of educational permeation (which involves a broad set of interrelated educational input and output factors that are strongly related to economic development), the samples' educational age, and publication year were all independently related to performance on Raven's matrices. Our data suggest that the Flynn effect can be found in high as well as low GNP countries, although its size is moderated by education-related sample and country characteristics and seems to be smaller in developed than in emerging countries.  相似文献   

Communication in performance‐based training and instruction: From design to practice     

Josephine A. Larbi‐Apau  James L. Moseley 《Performance Improvement》2009,48(9):7-16

Communication is inextricably important to instructional design and performance‐based training. Promoting effective communication as an integral part of the performance support system improves professional instructional design functions and offers greater avenues for meaningful discourse among end users of the instruction. In this article, we highlight communication in performance training and instruction for meaningful learning and effective exchange of knowledge. Internal and external communications are discussed as a means to promoting successful relationships, commitment, and ownership.  相似文献   

Significant life experiences affect environmental action: a confirmation study in eastern Taiwan     

Shih‐Jang Hsu 《Environmental Education Research》2009,15(4):497-517

Two field studies form the basis of this article. The major purposes of Study 1 were to examine significant life experiences affecting the cultivation of environmental activists in eastern Taiwan, and to reconstruct the life paths followed by those active people who engaged in effective environmental action. 40 usable autobiographical memories were collected and content‐analysed to derive 17 significant life experiences. Based on the 17 accounts, a quantitative questionnaire of 24 items on significant life experiences variables was developed for Study 2. Four hundred and thirty valid questionnaires were analysed. Eighty two respondents with a high level of environmental action were determined to be environmental activists, and 153 with a low level of environmental action were determined to be people apathetic towards environmental protection. It was found that the significant life experiences identified in Study 1 could effectively distinguish environmentally committed people from those apathetic to environmental protection. Study 2 also found that 54.6% of the variances in environmental actions could be explained by the significant life experiences.  相似文献   

Why ontology matters to reviewing environmental education research     

Heila Lotz‐Sisitka 《Environmental Education Research》2009,15(2):165-175

This paper responds to a keynote paper presented by William Scott at the 2007 World Environmental Education Congress held in Durban, South Africa. The keynote address reviewed 30 years of environmental education research. In this response to William Scott's paper I contemplate the way in which environmental education research may enable reflexivity in modernity and develop knowledge that can serve as cultural mediator between individual and society. Through emphasizing ontology, I consider the reality of global knowledge production in relation to the way in which ontology may influence the reasons how and why we come to do particular forms of research, providing an ontological reference for the ever‐expanding pluralism that characterizes the field of environmental education research. The paper comments on various aspects of the Scott paper, but presents an argument for not only valuing pluralism, methodological experimentation and ‘reaching out’, but for embracing the cosmopolitan implications of wider ontological referents of environmental concerns in environmental education research. The paper argues that research in environmental education ought to become ontologically defensible at both local and global scales.  相似文献   

What do we know about early sport specialization? Not much!     

Joseph Baker  Stephen Cobley  Jessica Fraser‐Thomas 《High Ability Studies》2009,20(1):77-89

In November 2005, the International Olympic Committee's Medical Commission issued a statement on Training the elite child athlete recommending that “more scientific research be done to better identify the parameters of training the elite child athlete”. This paper focuses on a specific issue related to training the child athlete: early specialization. While associations between early specialization and expertise development are highlighted, much research also suggests early specialization is associated with a range of negative consequences affecting physical, psychological, and social development. Alternately, some researchers have proposed that an early diversification approach does not disadvantage athletes in acquiring expertise, and is important for the development of intrinsic motivation and skill transferability. However, this review suggests that inadequate evidence exists to resolve the issue in favor of either approach.  相似文献   

Talented athletes and academic achievements: a comparison over 14 years     

Laura Jonker  Marije T. Elferink‐Gemser  Chris Visscher 《High Ability Studies》2009,20(1):55-64

The purpose of this study was to gain insight into the academic achievements of 200 talented athletes in 1992/1993 and 200 in 2006/2007, aged 14–16 years. When compared with the national average, the athletes in 2006/2007 attended pre‐university classes more often (χ² = 57.001, p<.05). Of the 2006/2007 athletes, a higher percentage participated in pre‐university programs compared with that of athletes in 1992/1993 (χ² (1, n = 400) = 32.003, p<.05), whereas the national averages showed stability (χ² = .325, p>.05). Investigating self‐regulation appears relevant, as talented athletes may have developed a high sense of self‐regulation in sports, which may enable them to optimally profit from their self‐regulatory skills in their academics.  相似文献