Noted

In the past, the world’s oceans have absorbed more than 40 percent of the carbon dioxide emitted by human activity. But a study by geologist Jeffrey Park, in the November 25 issue of Geophysical Research Letters, suggests that the oceans are losing some of this ability. The reason may be changes over the past 20 years in circulation or sea surface temperature; the result may speed up climate change.

Ghrelin, a hormone important in regulating appetite, memory, and learning, might prevent or slow the development of Parkinson’s disease. In the November 11 Journal of Neuroscience, School of Medicine biologist Tamas Horvath and colleagues showed that in mice, ghrelin has “neuroprotective effects” on the brain’s dopamine-secreting cells, the loss of which characterizes Parkinson’s. Horvath plans studies of humans to explore ghrelin’s use in diagnosis and therapy.

Norway Rats are, like us, a highly social species, which is why a study in a December Proceedings of the National Academy of Sciences has profound implications for humans. Psychiatry researcher Gretchen Hermes and her colleagues found that when female rats naturally susceptible to breast cancer were placed in isolation, the animals were 3.3 times more likely to develop mammary tumors.

Since 1994, federal guidelines have recommended that parents put infants to sleep on their backs to prevent Sudden Infant Death Syndrome. But in the December Archives of Pediatrics and Adolescent Medicine, pediatrics researcher Eve Colson and colleagues note that 45 percent of caregivers surveyed said their doctors did not recommend back sleeping. Further, progress toward back sleeping plateaued during 2003–07 and is lowest among African Americans, who are most likely to cite concerns about infant choking or comfort.