Infrared Absorption Spectra of Serpentine Cat＇s Eye from Sichuan Province of China

Infrared （IR） absorption spectra and X-ray powder diffraction （XRD） patterrns of sexpenfine cat＇s eye from Sichuan Province have been investigated, and infrared absorption bands of the serpentine have been assigned in this paper. The results indicate that the bands near 3 600 - 3 700 cm^-1 belong to the stretching absorption band VOH, the bands in 948 - 1 100 cm^-1 axe assigned to the stretching vibraling band Usvo, and the bands at 600 570 and 440 cm^-1 respectively belong to the bending vibration band VOH, δMg-O and δSi-O. The serpentine cat＇ s eye includes two types： chrysotile and antigorite. Chrysotile has a sharp and intensive band at 3 688 cm^-1 and a weak band at 3 643 cm^-1 , while antigorite has only one intensive band in the region. At vibration band VSi-O, chrysotile and antigorite have a similar feature at 1 071 cm^-1, but the band at 980 cm^-1 in anfigorite has been split into two bands in chrysotile - a strong one at 1 027 cm^-1 and a weak one at 949 cm^-1. In addition, antigorite has a characteristic bending vibrating band δMg-O at 570 cm^-1. Based on the analysis of the feature of crystal structure, their IR differences axe well explained.     

Beyond Punnett Squares: Student Word Association and Explanations of Phenotypic Variation through an Integrative Quantitative Genetics Unit Investigating Anthocyanin Inheritance and Expression in Brassica rapa Fast Plants

Genetics instruction in introductory biology is often confined to Mendelian genetics and avoids the complexities of variation in quantitative traits. Given the driving question “What determines variation in phenotype (Pv)? (Pv=Genotypic variation Gv + environmental variation Ev),” we developed a 4-wk unit for an inquiry-based laboratory course focused on the inheritance and expression of a quantitative trait in varying environments. We utilized Brassica rapa Fast Plants as a model organism to study variation in the phenotype anthocyanin pigment intensity. As an initial curriculum assessment, we used free word association to examine students’ cognitive structures before and after the unit and explanations in students’ final research posters with particular focus on variation (Pv = Gv + Ev). Comparison of pre- and postunit word frequency revealed a shift in words and a pattern of co-occurring concepts indicative of change in cognitive structure, with particular focus on “variation” as a proposed threshold concept and primary goal for students’ explanations. Given review of 53 posters, we found ∼50% of students capable of intermediate to high-level explanations combining both Gv and Ev influence on expression of anthocyanin intensity (Pv). While far from “plug and play,” this conceptually rich, inquiry-based unit holds promise for effective integration of quantitative and Mendelian genetics.     

A PERSONAL CONSTRUCT APPROACH TO EVALUATING TEACHING PRACTICE

During 1976, one of us decided to investigate the use of Kelly's personal construct theory and the triadic form of his repertory grid in enhancing understanding between a supervisor and a student‐teacher, when evaluating that student's teaching. An account of the procedure is given. In discussion, the student and supervisor agreed that the procedure, although long and demanding, led to a greater understanding of their own and each other's perspectives of the lesson evaluated. But it was admitted that the particular procedure employed and the use of the triadic form of the repertory grid are both time consuming and tiring. A rating form of the repertory grid in a simpler procedure was then explored in a similar teaching situation. An account of this second approach is also given. It was agreed that this approach was much simpler than in the original investigation and both student and supervisor (who were common to both investigations) found that it led to a greater understanding of their own and each other's perspectives. The authors therefore suggest that a rating form of the repertory grid (and the accompanying theory) can be used to enhance understanding between student‐teachers and their supervisors. They also propose that this would be a useful procedure in other educational contexts when an evaluation takes place.     

Effects of primer podcasts on stimulating learning from lectures: How do students engage?

A number of factors can influence learning from lectures such as students' prior knowledge, their motivation, the instructional design, the lecturer and so forth. Instructional aid techniques such as preparing class notes, giving quizzes (either planned or spot quizzes) and the like can be used to maximise learning. This study uses two well‐documented tools for learning from text—advance organisers and higher order questions—adapted for use with podcasts. Student evaluations of their experience of being primed for lectures with podcasts are described. The findings show that audio advance organisers and questions experienced by students have a positive influence on learning, because they help students bridge the conceptual distance between new and prior knowledge, better understand the topics in the lectures and stimulate thinking more deeply about the lecture's content and the possible applications of the subject of the lecture.     

Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors

The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.     

Development and validation of the preschool learning behaviors scale

This article presents the design, national standardization, and validation of the Preschool Learning Behaviors Scale (McDermott, Green, Francis, & Stott, 2000). A normative sample (N = 100) of 3‐ to 5–1/2‐year‐olds was configured to the U.S. Census, wherewith factor analyses yielded distinct and reliable dimensions of Competence Motivation, Attention/Persistence, and Attitude Toward Learning. The solution was invariant in an independent national sample (N = 170) and generalizable across child sex, age, ethnicity, and parent education level. Three‐week stability and interobserver agreement were supported with a local Head Start sample (N = 52). Bivariate and canonical correlations demonstrated validity convergence with indices of social skills, divergence from behavior problems, and substantial independence from cognitive ability. Implications and future research are considered. © 2002 Wiley Periodicals, Inc.