那拉提山北缘寒武纪玄武岩的元素地球化学特征及构造意义

我国西南天山地区那拉提北缘断裂北侧出露寒武纪（516.3±7.4Ma）橄榄拉斑玄武岩，其Al2O3（120.71％-14.14％）、P2O5（0.09％-0．21％）含量较低，TiO2（1.39％-2．35％）、MgO（5.35％-8.14％）含量中等，全Fe2O3（11.74％-16．03％）含量较高，球粒陨石标准化稀土分布型式平坦，（La／Sm）.和（Y／Nb）.比值接近1，为过渡型洋脊玄武岩（T-MORB）；并且Th／Ta比值（0．8—1.5）低，高场强元素（Nb，Ta，Zr，Hf，P）没有明显亏损，缺乏陆壳混染或俯冲带流体活动的印迹.部分T-MORB的Fe、Ti含量较高（FeO^T〉12％，TiO2〉2％，FeO^T／MgO〉1．75），Mg^#值（0．40—0.49）和Cr（53×10^-6-110×10^-6）含量较低，属于Fe-Ti玄武岩（ferrobasalt），应为岩浆依Fenner趋势发生较高程度结晶分离演化的产物，很可能形成于洋中脊的扩展型裂谷环境.我们认为，那拉提北缘寒武纪T-MORB和Fe-n玄武岩可能与境外吉尔吉斯斯坦境内北天山南缘的旱古生代Terskey蛇绿岩带相连，为Terskey蛇绿岩的残片；寒武纪我国境内发育Terskey洋.那拉提北缘断裂可能与尼古拉耶夫线相连，代表西南天山地区Terskey洋闭合形成的一条早古生代缝合带.     

Impact of simulator-based instruction on diagramming in geometrical optics by introductory physics students

We examine the conceptual development resulting from an instructional experiment with an interactive learning environment in geometrical optics for introductory high school physics. How did teaching-learning processes come to change the ways in which students depicted various everyday optical situations in paper and pencil graphical representations? We view conceptual development as a process resulting in part from increasingly aligning one's practices to a target community by means of participating in a community of practice that uses the target concepts. For formal science learning, this participation requires changes in concepts, epistemological attitude, and in the development and use of representational tools, including diagrams and technical language, as a means of communication. Results of our instructional experiment indicated that students went through major conceptual developments as reflected in the diagrams they constructed and supported by other representational tools and as judged in terms of several perspectives: in identifying the formation of shadows and images, in recognizing the eye as a participating factpr in the optical system, and in changing the types of justifications they provided in their optical reasoning from presuppositional to causal.     

如何阅读海德格尔

海德格尔的思想路径可以根据三个相继出现的引导词来追踪:存在的意义、存在的真理和存在的地形学,一般认为,阅读他的作品时要分两个步骤——从“存在的意义”到“存在的真理”;然后是“存在的地形学”——每一次都将他的思想更切近地带入到对开端的居有上.但如果唯独地形学提供了足以接近海德格尔从一开始就持续追问的唯一问题——存在问题的话,那么显然,他的作品需要倒退着阅读,而不是正序阅读.     

The Context of Thought Experiments in Physics Learning

This paper takes a cognitive perspective in an attempt to analyze mental mechanisms involved in contextual learning. In the following, it is suggested that contextualized environments evoke mental mechanisms that support reasoning about what if, imaginary situations – utilizing a powerful mental mechanism known from the history of physics as thought experiments (TEs). Thought experiments are associated with visualization of data and imagery that originate in implicit knowledge. This paper suggests that thought experiments rely on sensory memories constructed by the learner during past experience. Such sensory memories are activated by the context. The first part of the paper deals with the definition, nature, incidents, and experimental data related to implicit knowledge and TEs. Empirical results are then analyzed in order to explore the role of sensory memories and underlying schemata in TEs, thereby suggesting a set of embodied schemata that act as implicit assumptions and provide context-dependent epistemological primitives that underlie imaginary events in a manner that will statistically match the outer world.     

Enrollment patterns and academic performance as a function of registration under a pass-fail grading system

An experimental pass-fail grading system was examined to determine if interdisciplinary exploration was encouraged by modifying the competitive aspects of grading and to examine the performance of students enrolling in pass-fail courses in the light of their past achievement and the performance of classmates. Results of the study suggest that the pass-fail grading situation encouraged study across a wider area of subjects, but also was associated with lower achievement as reflected by a familiar grading scheme. A review of the literature indicated that a need for valid evaluation of student progress is acknowledged by virtually all writers, but that numerous arguments attack the manner in which grades are assigned and used and attack the lack of knowledge about the psychometric attributes of traditional grading arrangements.

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Résumé Un système expérimental de notation réussite-échec a été mis à l'étude afin de déterminer si l'on pourrait encourager l'exploration interdisciplinaire en modifiant les aspects compétitifs de la notation et aussi afin d'évaluer le rendement des étudiants inscrits aux cours notés selon système réussite-échec à la lumière des réalisations antérieures de ces étudiants et du rendement de leurs camarades de classe. Les résultats de cette étude laissent entendre que le système en question a encouragé les étudiants à porter leur intérêt vers un plus grand nombre de sujets, mais qu'il s'en est suivi des résultats moins brillants en comparaison des résultats obtenus par le système de notation classique. Une étude de la littérature publiée à ce sujet indique que presque tous les auteurs reconnaissent la nécessité de disposer d'une méthode d'évaluation valable des progrès des étudiants, mais il existe de nombreux arguments contre la façon dont les notes sont accordées et utilisées et contre le manque de connaissance des attributs psychométriques de la méthode de notation traditionnelle.