Problem-solving skills among precollege students in clinical immunology and microbiology: classifying strategies with a rubric and artificial neural network technology.

Educators emphasize the importance of problem solving that enables students to apply current knowledge and understanding in new ways to previously unencountered situations. Yet few methods are available to visualize and then assess such skills in a rapid and efficient way. Using a software system that can generate a picture (i.e., map) of students' strategies in solving problems, we investigated methods to classify problem-solving strategies of high school students who were studying infectious and noninfectious diseases. Using maps that indicated items students accessed to solve a software simulation as well as the sequence in which items were accessed, we developed a rubric to score the quality of the student performances and also applied artificial neural network technology to cluster student performances into groups of related strategies. Furthermore, we established that a relationship existed between the rubric and neural network results, suggesting that the quality of a problem-solving strategy could be predicted from the cluster of performances in which it was assigned by the network. Using artificial neural networks to assess students' problem-solving strategies has the potential to permit the investigation of the problem-solving performances of hundreds of students at a time and provide teachers with a valuable intervention tool capable of identifying content areas in which students have specific misunderstandings, gaps in learning, or misconceptions.

Temporal segregation in North American desert Membracidae.

Three species of Membracidae (Homoptera) have been found to coexist on the creosote bush, Larrea tridentata in the Mojave Desert. The insects are monophagous, univoltine and appear to avoid direct competition by temporal segregation. Multareis cornutus overwinters as slow growing nymphs and the adult population peaks in March. Centrodontus atlas overwinters in the egg stage with rapidly growing nymphs appearing in March while the adult population peaks in June. Multareoides bifurcatus overwinters as adults with the adult population peak in July. Nymphs occur in May-June. The various species have evolved cryptic form and coloration which is associated with phenology of the host plant. It is postulated that this has contributed to the evolution of temporal segregation.