How to realize a negative refractive index material at the atomic level in an optical frequency range?

INTRODUCTION Recently, a new type of artificial compositematerials (so-called left-handed media or negativerefractive index media) whose electric permittivityand magnetic permeability are simultaneouslynegative (corresponding to a negative refractiveindex) over a certain frequency band has attractedconsiderable attention due to its extraordinaryelectromagnetic properties (Pendry, 2000; Shelbyet al., 2001; Grbic and Eleftheriades, 2004; Chen eal., 2004). The negative refractive inde…     

The Views of Youth on Their Educational Rights: A Case Study of Secondary Students from two Northern Ontario High Schools

A case study is reported involving 32 applied and academic program student volunteers aged 15–18 years from two high schools located in Northern Ontario, Canada. Students were interviewed regarding a number of educational policy and school climate issues. The study examines perceptions of rights as an aspect of the school learning environment. The need for greater school community and additional supports for struggling students was voiced by students across both program groups. Students strongly endorsed either a meritocratic or an equalitarian perspective on rights issues with both philosophies represented to some extent in both program groups. Surprisingly, students across both program groups expressed little interest in their education rights or their legal rights generally. The importance of fostering school community and student interest in rights issues is discussed. Also considered is the role of the social science researcher in providing youth a forum for the discussion of social policy issues.     

The design,implementation, and evaluation of a digital interactive globe system integrated into an Earth Science course

The aim of this study is to design and implement a digital interactive globe system (DIGS), by integrating low-cost equipment to make DIGS cost-effective. DIGS includes a data processing unit, a wireless control unit, an image-capturing unit, a laser emission unit, and a three-dimensional hemispheric body-imaging screen. A quasi-experimental study was conducted to evaluate the learning effectiveness of our system. A total of 105 junior high-school students from Taiwan participated in this 8-week experiment. The students were divided into three individual groups of 35 students each, with one control group and two experimental groups (EG1 and EG2). The results of one-way mixed design ANOVA indicated that participants in the experimental group, who used the DIGS, outperformed the other two groups, in the post-test as well as in the delayed test. These findings demonstrate that the proposed DIGS can effectively enhance the performance of the learners in an Earth Science course.     

Understanding Nonsocial Play in Early Childhood

Nonsocial play continues to be perceived as a behavior that is detrimental young children’s development. The research evidence in this area is mixed but lends itself to a more positive view of nonsocial play. Despite the substantial amount of literature available, the terminology used fails to be consistent and may prove to be distracting and confusing to practitioners and caregivers. This paper reviews the current literature on young children’s nonsocial play. Distinctions among different types of nonsocial play are identified, as well as some reasons children engage in these activities. By developing a better understanding of the role of nonsocial play in early childhood, caregivers may better understand when children need their help in promoting more social types of play and when intervention may or may not be necessary.     

Authors Index, Volume 23 (2001)

Authors Index

Authors Index, Volume 23 (2001)     

Characteristics of 5th Graders' Logical Development Through Learning Division with Decimals

When we consider the gap between mathematics at elementary and secondary levels, and given the logical nature of mathematics at the latter level, it can be seen as important that the aspects of children's logical development in the upper grades in elementary school be clarified. In this study we focus on the teaching and learning of “division with decimals” in a 5th grade classroom, because it is well known to be difficult for children to understand the meaning of division with decimals, caused by certain conceptions which children have implicitly or explicitly. In this paper we discuss how children develop their logical reasoning beyond such difficulties/misconceptions in the process of making sense of division with decimals in the classroom setting. We then suggest that children's explanations based on two kinds of reversibility (inversion and reciprocity) are effective in overcoming the difficulties/misconceptions related to division with decimals, and that they enable children to conceive multiplication and division as a system of operations.     

Talking About Teaching Episodes

This paper examines two types of discourse in which teachers engage when discussing case studies based on classroom episodes, and the ways in which the availability of video data of these episodes may motivate a shift in the mode of discourse used. We interviewed two pairs of secondary school mathematics teachers after they had read a case study based on a 16-minute mathematics classroom episode taped in a secondary school in the United States. During each interview, a multimedia version of the case study, including video of the original episode, was available to the participants. We identify two modes of discourse engaged in by the teachers during the interviews: Grounded Narrative and Evaluative Discourse. We examine and identify the characteristics of the two discourse forms, drawn from both video and textual analysis. These characteristics are self-reflective talk, perspective, ethics, and linguistic patterns. The identification of two modes of discourse is relevant for researchers and teacher educators using case studies or video recordings. In addition, the findings provide insight into how teachers are “seeing” classroom events in a video case study.     

Sensitivity analyses of cables to suspen-dome structural system

The construction of the cables is a key step for erecting suspen-dome structures. In practical engineering, it is difficult to ensure that the designed pre-stresses of cables have been exactly introduced into the structures in the site; so it is necessary to evaluate the influence of the variation of the pre-stresses on the structural behavior. In the present work, an orthogonal design method was employed to investigate the pre-stressed cables'sensitivity to the suspen-dome system. The investigation was concentrated on a Kiewitt suspen-dome. Parametric studies were carried out to study the sensitivity of the structure's static behavior, dynamic behavior, and buckling loads when the pre-stresses in the cables varied. The investigation indicated that suspen-dome structures are sensitive to the pre-stresses in all cables; and that the sensitivity depended on the location of the cables and the kind of structural behavior. Useful suggestions are given at the end of the paper.     

Clusters,Innovation and Tertiary Education

The purpose of this paper is to investigate the integration between research findings produced at the University and Community College levels and local SMEs (small and medium enterprises) as it impacts regional innovation systems and in particular the prospect of cluster formation. The paper explores certain factors that have been identified in international literature as being critical to fostering innovation in non-metropolitan regions. These factors include government policies and programmes, internal and external infrastructure, partnership or research links among educational institutions, and support from local business and civic leaders. Stakeholders from non-metropolitan regions were asked to judge the level of effectiveness with reference to these development “factors” while highlighting weaknesses, strengths, and effects on innovation in their locale.     

Solid-phase microextraction for flavor analysis in Harari Khat (<Emphasis Type="Italic">Catha edulis</Emphasis>) stimulant

This research examined the typical flavor compounds in the commonest type of Khat called Harari Khat grown in the region of Ethiopia. Twenty-eight compounds, which includes 1,2-Propanedione, 1-Phenyl, Hexanol, Hexanal compounds, Limonene, Benzaldehyde with other flavors, were extracted by polydimethylsiloxane at room temperature for 30 min from Khat samples, and identified by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). This method needs no organic solvents and required minimal sample. Project supported by scholarship from China