Students' Learning Strategies With Multiple Representations: Explanations of the Human Breathing Mechanism

The purpose of this study was to understand how students utilized multiple representations to learn and explain science concepts, in this case the human breathing mechanism. The study was conducted with Grade 11 students in a human biology class. Semistructured interviews and a two-tier diagnostic test were administered to evaluate students’ learning strategies of integrating multiple representations. The functions of multiple representations (complementary, constraining, and deeper understanding) suggested by Ainsworth (2008) were adapted as the analytical framework to better describe the participating students’ learning strategies with multiple representations (access complementary information, apply one representation to interpret the other, and evaluate representations). The categorization of students’ learning strategies facilitated interpreting their diverse understanding in relation to the multiple representations. In addition to a summary of students’ learning strategies, three case examples are presented to show how the framework was applied in the analysis and to discuss how the learning strategies interacted with students’

The Development of a Conceptual Framework and Tools to Assess Undergraduates' Principled Use of Models in Cellular Biology

Recent science education reform has been marked by a shift away from a focus on facts toward deep, rich, conceptual understanding. This requires assessment that also focuses on conceptual understanding rather than recall of facts. This study outlines our development of a new assessment framework and tool—a taxonomy— which, unlike existing frameworks and tools, is grounded firmly in a framework that considers the critical role that models play in science. It also provides instructors a resource for assessing students' ability to reason about models that are central to the organization of key scientific concepts. We describe preliminary data arising from the application of our tool to exam questions used by instructors of a large-enrollment cell and molecular biology course over a 5-yr period during which time our framework and the assessment tool were increasingly used. Students were increasingly able to describe and manipulate models of the processes and systems being studied in this course as measured by assessment items. However, their ability to apply these models in new contexts did not improve. Finally, we discuss the implications of our results and the future directions for our research

Alternative Conceptions and the Learning of Chemistry

A great deal of research has indicated that teaching is rarely a matter of introducing learners to material that simply replaces previous ignorance, but is more often a matter of presenting ideas that are somewhat at odds with existing understanding. In subjects such as chemistry, learners at school and university come to their studies already holding misconceptions or 'alternative conceptions' of subject matter. This has implications for subsequent learning, and so for teaching. This article reviews a number of key issues: (i), the origins of these alternative conceptions; (ii), the nature of these ideas; and, (iii), how they influence learning of the chemistry curriculum. These issues are in turn significant for guidance on (a) how curriculum should be selected and sequenced, and (b) on the pedagogy likely to be most effective in teaching chemistry. A specific concern reported in chemistry education is that one source of alternative conceptions seems to be instruction itself.None

Intramolecular Reductive Heck Approach to Guaipyridine Alkaloids

The guaipyridine alkaloids are a family of compounds that all share an unusual carbon structure, whose source plants have been used as a traditional medicine in Southeast Asia. Members of the guaipyridine family include cananodine and the rupestines. Cananodine has been isolated from the fruits of the Canaga odorata in Indonesia, Malaysia and the Philippines. Cananodine has been used of decades as a traditional medicine for the treatment of malaria, infections and fever. Studies of cananodine’s biological activity have reveled activity against Hep G2 and Hep 2,2,15 human hepatocarcinoma cell lines, the most common types of liver cancer. Due to the similarities in structure, there is strong evidence to suggest that other members of the guaipyridine alkaloid family will have anti-cancer activity. Progress toward the synthesis of the guaipyridine skeleton using an intramolecular Heck reaction will be presented along with a nearly complete synthesis of rupestine D