Random Samples

Science  15 Dec 2006:
Vol. 314, Issue 5806, pp. 1663

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  1. NETWATCH: A New Look at Leonardo

    What do the mountains in the background of the Mona Lisa reveal about Leonardo da Vinci's knowledge of erosion? What can high-tech scanners tell us about his other work? Find out at the nifty exhibit Universal Leonardo from the University of the Arts London. One section explores how Leonardo's writings, sketches, and paintings reflect his view of the world, where all things—from the motion of water to the curling of hair—are connected through the geometrical rules that govern nature.

    Another highlight is an investigation of what different imaging techniques have uncovered about the history of Leonardo's 1501 painting Madonna of the Yarnwinder. For instance, a profilometric analysis, which uses a laser to map the painting's tiny variations in height, shows that some restorers “repaired” undamaged sections, such as the child's right cheek. An ultraviolet scan also reveals touchups on the infant's calf and hip.



    Depression doesn't just put a lid on feelings. Many depressed people also complain of blunted taste sensations, a finding that has been hard to explain.

    Diminished levels of certain types of brain neurotransmitters may be the reason, according to researchers at the University of Bristol in the U.K. The group, led by physiologist Lucy Donaldson, has shown that healthy volunteers who received a selective serotonin reuptake inhibitor, which increases serotonin levels in the brain, became supersensitive at detecting sweet and bitter tastes. Those who received an antidepressant that enhances noradrenaline became more sensitive to sour and bitter, the researchers reported last week in the Journal of Neuroscience.

    The dampening of taste is probably not happening in the brain itself, as some have thought, Donaldson says: “Our hypothesis is that this is happening at the level of the taste buds.” Although serotonin and noradrenaline are both known to be involved in taste signaling, the connection between mood and taste-bud activity is new. “It may be feasible to use a simple [taste] test to see what kind of medication people should be given,” says Donaldson, who plans to repeat the experiment with depressed subjects to see whether they are more insensitive to sweet or sour tastes.


    “I'm very excited by this paper,” says taste researcher Stephen Roper of the University of Miami Miller School of Medicine in Florida, who adds that it “confirms and extends” the connection between serotonin and taste transmission.


    Australia last week became the latest in a handful of countries to explicitly approve the practice of therapeutic cloning—otherwise known as somatic cell nuclear transfer (SCNT)—for scientists working with human embryonic stem cells.

    By a vote of 82 to 62, the House of Representatives in Canberra defied the country's political leadership, including Prime Minister John Howard, and endorsed a vote by the Senate last month, ending a 4-year ban on SCNT. The new law requires destruction of SCNT-created embryos within 14 days. It also adds a restriction: Insertion of human genetic material into animal eggs is not allowed.

    Australian scientists are “elated” at the development, which may enable them to generate genetically tailored populations of stem cells to study diseases, says stem cell researcher Alan Trounson of Monash University in Melbourne.

    The new law should also boost attendance at the 5th annual meeting of the International Society for Stem Cell Research, which will be held in Cairns, Australia, in June.


    The London-based International Maritime Organization was expected to vote last week to shift shipping lanes off the Massachusetts coast in order to protect whales.

    The decision is based on a 4-year effort by scientists to map the distribution of baleen whales 50 kilometers off Boston Harbor. Currently, hundreds of baleens, including the endangered North Atlantic right whale, feed on fish and plankton in the Stellwagen Bank National Marine Sanctuary. But roughly one whale per year is struck by the 200 shipping vessels that pass through the harbor monthly, and scientists say the recovery of the right whale, thought to number only 350, is hampered by these accidents, as well as by ships' fishing nets.

    By poring over 25 years of whale observations, U.S. government and sanctuary researchers found that the current shipping lane passes directly through a high-density region of whale feeding (red area on map). So they proposed to shift the lane up to 16 km north (dotted line) and to narrow it by 20%, to 7.4 km. The Boston Harbor Pilot Association fears that the narrower lane will lead to more ship collisions, but others say it is safe given the precision afforded by Global Positioning Systems.


    The change would add only 15 minutes to the trip and prevent most whale strikes, what Stellwagen's Craig McDonald calls “an enormous conservation benefit for a minimal cost.”