Exact solutions for concentration dependent diffusion and the inverse complementary error function

A direct method of studying the qualitative behavior of concentration dependent diffusion is based on exact solution of problems with diffusion coefficients which are piecewise constant functions of concentration. Polynomial approximations are given for the inverse of the complementary error function. They facilitate the direct method and also Philip's inverse method of studying qualitative behavior.     

抗战时期美国传教士对共产党的看法

传教士对共产党的印象和评价是十分重要的,它对于美国外交政策和国内公众舆论有着特别的影响.     

Instructional practices of teachers enrolled in educational technology and general education programs

This study investigated classroom practices of 38 teachers enrolled in university masters' degree programs in educational technology and in other areas of education. The classroom practices related to five key concepts associated with educational technology: (a) learner-centered instruction, (b) instructional design, (c) media and technology, (d) assessment, and (e) instructional alignment. Teachers rated their frequency of use of desirable practices in these five areas on a 30-item Likert type survey. In addition, one class of students per teacher rated its own teacher's frequency of use of the practices on 20 items parallel to items on the teacher survey. The mean overall rating across all teachers for the classroom practice items was very close to Often, or 4.0, on the 5-point scale. There were few reported differences between the teachers enrolled in educational technology programs and those enrolled in other education programs. Student ratings indicated less frequent teacher use of the desirable practices on 16 of the 20 common items, with significantly lower student ratings on 8 of these items. However, there was strong teacher-student agreement on several other comparisons.The study reported in this article was conducted as a doctoral dissertation at Arizona State University.     

The Use of the Microgenetic Method with Children with Disabilities: Discovering Competence

In this paper, we advocate the use of the microgenetic method, a methodology that combines dense sampling of observations across time and extensive trial-by-trial analysis, to examine strategy change in children with disabilities. This methodology has revealed new information about normally achieving children's cognition, such as large individual variability in strategy use among children of the same age and more gradual patterns of strategy change than previously assumed. In this paper, we review data from three different microgenetic studies in the domains of memory, arithmetic, and reading with children with or at risk for mental retardation and normally achieving children. Our review indicates that there are similar sequences of strategy change, similar rates of strategy change, and similar frequency of strategy discovery and use in children with and without mental retardation (compared to mental age peers). Implications are discussed for the use of this methodology to design instructional techniques for children with disabilities.     

Teaching Science Effectively With Analogies: An Approach for Preservice and Inservice Teacher Education

Journal of Science Teacher Education -     

Some new evidence of the character of competition among higher education institutions

This study employs a simple enrollment demand model to investigate the regional market environment of a private, church-related, comprehensive institution of higher education offering undergraduate, graduate and professional education. The focus is on price and cross-price elasticities of demand as measures of the competitive threat posed by prominent public and private educational alternatives within the region. We find a significant competitive threat coming from the private sector within the region. This competition raises the net price elasticity of demand for education at this institution to well above unity. We conclude that tuition price subsidies play a critical role in managing enrollment demand at this institution. [JEL J3, J24, J41]