Archeological evidence for pimple (pralrie) mound genesis

Archeological deposits have been discovered in three pimple mounds on the upper Texas coast. Such incorporation indicates that (i) these particular mounds are aggradational rather than erosional in origin; (ii) mound formation continued until at least A.D. 1100 to 1200; (iii) each mound took 300 to 500 years to form; (iv) mounds within the same mound field did not form simultaneously; (v) certain Gulf Coast pimple mounds have archeological research potential; and (vi) archeological data also offer a means for investigating mound formation.     

Acyclic stereocontrol through the aldol condensation

For the scientist who wishes to synthesize complex organic compounds, the most difficult problem is often establishing the correct configuration at the various chiral centers as the synthesis is being carried out. In the past decade, there has been an increasing effort to find direct solutions to this problem, which is particularly acute in the synthesis of acyclic and other conformationally flexible molecules. One of the oldest organic reactions, the aldol condensation, is emerging as a powerful tool for use in achieving such stereocontrol.