This paper discusses plane symmetry groups, also known as planar crystallographic groups or wallpaper groups. The seventeen unique plane symmetry groups describe the symmetries found in two-dimensional patterns such as those found on weaving patterns, the work of the artist M.C. Escher, and of course wallpaper. We shall discuss the fundamental components and properties of plane symmetry groups.

How well do U.S. students read? In this article, Sean Reardon, Rachel Valentino, and Kenneth Shores rely on studies using data from national and international literacy assessments to answer this question. In part, the answer depends on the specific literacy skills assessed. The authors show that almost all U.S. students can "read" by third grade, if reading is defined as proficiency in basic pr...

This report by George G. Somjen, for the Commission on Teaching Physiology, International Union of Physiological Sciences, presents a summary of answers received to a questionnaire concerning the state of Physiology Teaching. One hundred seventeen responses have been received from fifty countries. The results have been tabulated and contain information about the teaching methods and resources a...