Three dimensional couette flow and heat transfer through a porous medium with variable permeability

This paper reports research on the effects of variations in injection velocity and permeability on the heat transfer and flow through a highly porous medium between two horizontal parallel plates situated at constant distance with constant suction by the upper plate. Due to this type of variation in injection velocity and in permeability the flow becomes three dimensional. The governing equations are solved by adopting complex variable notations to obtain the expressions for the velocity and temperature field. The skin-friction along the main flow direction and rate of heat transfer are discussed with the help of graphs.     

History Run Wild: The Alternate World of Joan Aiken’s <Emphasis Type="Italic">The Wolves of Willoughby Chase</Emphasis> Series

This article examines the historical fantasy world created by Joan Aiken in the eleven volumes of her Wolves of Willoughby Chase series. In particular it looks at her subversion of historical reality by the creation of an alternative yet recognisable representation of our own world, using a wide range of events, and the remoulding of aspects of language and geography. It also discusses her reasons for writing in this form and explores the character of Dido Twite as heroine and major raison dtre of the series.This revised version was published online in May 2005 with corrections to the article title.     

Comparing active delay and procrastination from a self-regulated learning perspective

Researchers have proposed that the act of postponing academic work may be divided into a traditional definition of procrastination, viewed as maladaptive, and adaptive forms of delay. Adaptive forms of delay may be more consistent with certain facets of self-regulated learning. The current study investigated this issue by examining whether the relations between aspects of self-regulated learning and active delay may be distinct from the relations these aspects of self-regulated learning have with procrastination. Among 206 undergraduates, procrastination was positively predicted by mastery-avoidance goals and negatively by metacognitive strategy usage, whereas active delay was negatively predicted by avoidance goals and positively by self-efficacy. Furthermore, students who reported higher levels of active delay also received better grades. These findings provide support that active delay is a distinct form of delay from procrastination that may be more positive due to its associations with some adaptive self-regulatory processes and academic achievement.     

Expertise Differences in the Comprehension of Visualizations: a Meta-Analysis of Eye-Tracking Research in Professional Domains

This meta-analysis integrates 296 effect sizes reported in eye-tracking research on expertise differences in the comprehension of visualizations. Three theories were evaluated: Ericsson and Kintsch’s (Psychol Rev 102:211–245, 1995) theory of long-term working memory, Haider and Frensch’s (J Exp Psychol Learn Mem Cognit 25:172–190, 1999) information-reduction hypothesis, and the holistic model of image perception of Kundel et al. (Radiology 242:396–402, 2007). Eye movement and performance data were cumulated from 819 experts, 187 intermediates, and 893 novices. In support of the evaluated theories, experts, when compared with non-experts, had shorter fixation durations, more fixations on task-relevant areas, and fewer fixations on task-redundant areas; experts also had longer saccades and shorter times to first fixate relevant information, owing to superiority in parafoveal processing and selective attention allocation. Eye movements, reaction time, and performance accuracy were moderated by characteristics of visualization (dynamics, realism, dimensionality, modality, and text annotation), task (complexity, time-on-task, and task control), and domain (sports, medicine, transportation, other). These findings are discussed in terms of their implications for theories of visual expertise in professional domains and their significance for the design of learning environments.     

Facilitating Understanding of Movements in Dynamic Visualizations: an Embodied Perspective

Learners studying mechanical or technical processes via dynamic visualizations often fail to build an accurate mental representation of the system’s movements. Based on embodied theories of cognition assuming that action, perception, and cognition are closely intertwined, this paper proposes that the learning effectiveness of dynamic visualizations could be enhanced by grounding the movements of the presentation in people’s own bodily experiences during learning. We discuss recent research on embodied cognition and provide specific strategies for how the body can be used to ground movements during the learning process: (1) making or observing gestures, (2) manipulating and interacting with objects, (3) using body metaphors, and (4) using eye movements as retrieval cues. Implications for the design of dynamic visualizations as well as directions for future research are presented.     

Going Outside in Winter: A Qualitative Study of Preschool Dressing Routines

The exploratory study focused on describing typical routines of preparing for winter outdoor play with preschool children and their teachers. Naturalistic observations, interviews and photographs resulted in extensive examples of children’s development in cognitive understanding of winter and winter-related concepts. Observations of teachers and assistants revealed task-oriented perspectives including detailed strategies and planning. Asynchronous communication and directive language were typical of teacher/child communication. Photo analyses confirmed physical skills used by preschoolers to accomplish dressing tasks and extensive curricular changes to indoor environments.     

Effectiveness of Case-Based Learning Instruction on Epistemological Beliefs and Attitudes Toward Chemistry

The purpose of the study was to investigate the effectiveness of case-based learning instruction over traditionally designed chemistry instruction on eleventh grade students’ epistemological beliefs and their attitudes toward chemistry as a school subject. The subjects of this study consisted of 63 eleventh grade students from two intact classes of an urban high school instructed with same teacher. Each teaching method was randomly assigned to one class. The experimental group received case-based learning and the control group received traditional instruction. At the experimental group, life cases were presented with small group format; at the control group, lecturing and discussion was carried out. The results showed that there was a significant difference between the experimental and control group with respect to their epistemological beliefs and attitudes toward chemistry as a school subject in favor of case-based learning method group. Thus, case base learning is helpful for development of students’ epistemological beliefs and attitudes toward chemistry.     

A Qualitative Examination of the Challenges, Resources, and Strategies for Serving Children Learning English in Head Start

The dramatic growth in the number of children learning English as a second language in our country has led to a corresponding increase in the need to understand how teachers and schools can effectively teach children who are learning English as a second language. Many teachers report not feeling prepared to meet the needs of these children (National Center for Education Statistics, Teacher preparation and professional development: 2000. , 2002). The current study used focus group interviews to examine how Head Start teachers in one program addressed the special learning needs of children learning English in their classrooms. Key challenges involved communicating with children and their families in their home language. Teachers used other staff, parents, and children in the classroom to interpret. Strategies involved visual aids, pictures, gestures, and a welcoming classroom environment. Resources used by teachers were professional development and language skills of other staff. However, available resources were often underutilized and limited for teachers to use in meeting the challenges the teachers faced in the classroom. Suggestions are presented for overcoming the challenges and limited resources encountered by teachers, such as changes in preservice and inservice training opportunities, and second language learning opportunities for teachers. Further implications for training and research are discussed.