SEDIMENT 1 (IMAGE) Rice University Caption Rice University postdoctoral researcher Hongbo Ma holds sand from the Mississippi River, left, and silt from China's Yellow River. Ma led a study that showed particle size controls how sediment moves in flowing rivers changes dramatically when the grains are about 150 microns in size. Credit Rice University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.