Noted

The rocks that make fossil hunting so difficult are helping scientists understand how certain dinosaur species avoided conflicts over food and territory. Paleontologists Tyler Lyson and Nick Longrich, examining North American fossils about 65 million years old, showed that duckbills tend to be found in sandstone deposits, indicating a preference for a riverside habitat. Horned dinosaurs, also plant-eaters, are usually found in mudstones—a sign that they lived a few miles inland. The study appeared in the Proceedings of the Royal Society B.

Terminal cancer patients who enter hospice programs but later drop out are likely to rack up bigger health care bills, and are much more likely to die in a hospital, than those who stay. In a Journal of Clinical Oncology study, public health professor Elizabeth H. Bradley and her colleagues found that, of 90,000 hospice patients, the 10 percent who disenrolled incurred an average of about five times the Medicare expenses of the others.

Carl Sagan famously suggested that there were “billions upon billions” of stars in the universe. But according to a new assessment by Yale astronomer Pieter van Dokkum and his colleagues, Sagan’s estimate was way too low. At the W. M. Keck Observatory in Hawaii, the astronomers discovered that hard-to-see stars called red dwarfs are far more common than anyone realized. The new stellar count, reported in Nature,is 300 sextillion—3 followed by 23 zeros—a threefold increase over previous estimates.

How many links in the food chain of a stream or river? The answer varies with the abundance of nutrients in the ecosystem. But ecologist David Post and his colleagues have now shown that it tracks more closely with something unexpected: flow rate and volume. Their analysis of 36 North American rivers, published in Science, showed that both floods and droughts shortened food chains by changing the feeding habits of the largest fish—or even killing them off.

In a study of young low-income mothers, public health professor Jeannette Ickovics and coworkers found that the majority gained too much weight during pregnancy and were still overweight a year after delivery. Just over half the women were overweight or obese when they got pregnant, but a year after birth, the proportion was 68 percent. (The research appeared in the American Journal of Obstetrics & Gynecology.)