New details are emerging on how the melting poles could raise ocean heights [see "The Unquiet Ice"; SciAm, February 2008]. Researchers at the University of Toronto and Oregon State University suggest that the rise could be uneven around the world. They examined the West Antarctic ice sheet, which contains enough grounded ice to boost global sea levels by five meters if it splashed into the water. But such a huge redistribution of mass in Antarctica would reduce the gravitational pull in the area and shift the earth's rotation axis by 500 meters. Taking these and other factors into account, they figure that the seas will drop near Antarctica but rise in the Northern Hemisphere by an additional one to two meters above previous estimates. Gravitate toward the analysis in the February 6 Science.
Those fingertip whorls aren't just good for gripping objects and identifying people; they also enable you to feel fine textures and tiny objects. French researchers constructed two mechanical sensors, one with a ridged end tip and another with a smooth one; they then ran them over various textured surfaces, measuring the vibrations picked up by the fingerprinted sensors. Each ridge magnified the frequency range well suited for detection by nerve endings in the skin called Pacinian corpuscles. The work, published online January 29 by Science, helps to explain how the sense of touch accurately informs our surroundings [see "Worlds of Feeling"; SciAm Mind, December 2004].
Forward with Stem Cells
Researchers at Northwestern University stopped and, in some cases, reversed the effects of early-stage multiple sclerosis, a disease in which the immune system attacks the central nervous system. The investigators removed from the bone marrow so-called hematopoietic stem cells, which resupply the body with fresh blood cells, then used drugs to destroy the patients' existing immune cells. Injected back into the patients, the stem cells apparently "reset" the body's defenses so that they do not mistakenly go after healthy tissue. The study, published online January 30 in the Lancet Neurology, involved only 21 patients, however, so more complete trials are needed to assess the approach.
Data on stem cell therapies in general should increase soon: the U.S. Food and Drug Administration approved in January the first human embryonic stem cell trial a decision long awaited by scientists [see "The Stem Cell Challenge"; SciAm, June 2004]. It will enable Geron Corporation in Menlo Park, Calif., to test embryonic stem cells on 10 patients with spinal cord injuries.
Mooned by the Moon
Some four billion years ago the far side of the moon may have faced Earth. Mark Wieczorek and Mathieu Le Feuvre of the Institute of Earth Physics in Paris propose that if the moon had always faced the same way, it would have more craters on its leading side, where it encountered heavy bombardment during the early years of the solar system [see "The New Moon"; SciAm, December 2003]. Younger craters follow this pattern, but older craters do not; they instead cluster on the trailing edge, suggesting that it was once in front. An asteroid or comet strike could have spun the moon 180 degrees to its current orientation. The journal Icarus posted the conclusion online on December 31, 2008.