Triadic interaction in clinical task-based interviews with mathematics teachers

A clinical task-based interview can be seen as a situation where the interviewer–interviewee interaction on a task is regulated by a system of explicit and implicit norms, values, and rules. This paper describes how documenting and mapping triadic interaction among the interviewer, the interviewee, and the knowledge negotiated can be used to increase procedural replicability of the interview and accuracy of drawn conclusions about the interviewee’s thinking process. Excerpts from interviews with 25 inservice mathematics teachers working on a task to make up a problem whose solution requires division of two fractions are discussed. The excerpts illustrate the relationship between methodological decisions taken by the interviewer during the interview and the applicability of the interview output to the research questions. A divergent analysis of the interviews with these teachers, which spanned over two years and were conducted by four interviewers, is used to offer a framework for analyzing data collected in clinical task-based interviews.     

Education and social cohesion: developing a framework for education sector reform in Sri Lanka1

There is increasing interest in understanding and describing the links between education and ‘social cohesion’. However, the theoretical and empirical base for understanding these links is limited. There is also a shortage of practical tools for education policy‐makers and planners, to help them assess the impact of policies and investments, and to plan for future reform. This paper describes the initial development of an analytical and planning framework for addressing education and social cohesion within the context of a sector‐wide approach to education reform in Sri Lanka. A brief literature review suggests three inter‐connected domains in which links between education and social cohesion might be usefully analysed, together with three working hypotheses: (i) political economy/governance: education affects social cohesion through transparency and participation in education policy formulation, planning and management; (ii) equity/equality of opportunity: education affects social cohesion through the distribution of education resources, opportunities and outcomes; (iii) teaching/learning: education affects social cohesion through the development of certain competencies in students. Drawing on this analytical framework, research conducted in Sri Lanka is used to identify a set of interventions to promote social cohesion, with corresponding baseline, process and outcome indicators as benchmarks for measuring the progress and impact of intended policy measures. This process is described within the context of a ‘sector‐wide approach’ to education reform, intended to bring together the activities of the government and external partners within a single comprehensive medium‐term planning and budgetary framework.     

基于核密度估计多样性采集的背景建模算法

1IntroductionBackground subtraction methods are extensively ex-ploited for moving object detection in videos in manyapplications ,such as traffic monitoring[1],human mo-tion capture[2]and video surveillance[3]. The centralidea behind such methods is to segment foreground ini mage sequences taken from a fixed camera by com-paring each newframe to a model of the scene back-ground . Therefore , correctly and efficiently modelingand updating the background model is one of the mostchallenging aspec…     

The study of butterflies

In this part of the series on butterflies, we look at the types of variations found within species as well as their causes.     

Conversion of CO<Subscript>2</Subscript> to useful substances with composite iron,nickel, and copper catalysts

Composite materials of Fe/Al₂O₃, which consist of small particles of iron supported by thermally stable alumina even at 500–700 °C, have been widely used in the water-gas shift reaction for natural gas reforming. Therefore, Fe/Al₂O₃ is one of the promising candidates for re-transformation of exhausted CO₂ into fuels such as alcohols and hydrocarbons. The development of a CO₂ reforming system using the composite materials of Fe/Al₂O₃ through CO₂ reduction to CO, dissociation of water into hydrogen, and methanol synthesis has been investigated. It was found that dry and steam (i.e. wet) reforming of CO₂ produced almost the same amount of CO. At a temperature above 500 °C, maximal and saturated yields of CO and H₂ from CO₂ and water were obtained. However, this CO₂ reforming system requires higher-pressure conditions from several tens to hundreds standard atmospheric pressure in order to achieve high yield and selectivity for methanol production. In this study we developed the modified CO₂ reforming system by the utilization of Ni and/or Cu instead of Fe in order to obtain other types of useful products such as CO, CH₄, and carbon, more efficiently and selectively under atmospheric pressure. When Ni or Cu was used, conversion of CO₂ was reduced to 76%, while 9% of methane was detected in the case of Ni. On the other hand, though the CO₂ conversion reduced half of the Fe, the selectivity of CO from CO₂ increased to 95% in the case of Cu.