Random Samples

Science  20 Jun 2008:
Vol. 320, Issue 5883, pp. 1569

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  1. A Fiery, Dark Day

    To poet John Greenleaf Whittier, it was “A horror of great darkness” when “Men prayed, and women wept.” By noon of 19 May 1780, the pall cast over coastal New England was so deep that citizens of Portland, Boston, and Providence had to eat their midday meals by candlelight. Many thought the Day of Judgment was at hand.

    After the darkness lifted the next day, all manner of explanations came forth, including volcanic outpourings and celestial machinations. Now, researchers say they have traced the source of the darkness to forest fires 600 kilometers to the northwest.

    Erin McMurry of the University of Missouri, Columbia, and colleagues base their conclusion on tree ring records from fire-damaged trees around North America. In the International Journal of Wildland Fire, the researchers report that 1780 was a big year for forest fires in eastern North America, due in part to drought around the Great Lakes. New England's noontime darkness, they found, most likely resulted from the smoke of fires that spanned at least 2000 square kilometers in southern Ontario. At one Ontario burn site, fire swept in just after distinctive wood tissue began forming early in the growing season, consistent with the timing of the darkness.

    The forest-fire hypothesis “is plausible,” says Stephen Pyne of Arizona State University in Tempe, author of Fire in America. Proving it, however, would require better records of weather and winds on that day, he says—points on which the tree rings are silent.

  2. Rating Big Pharma


    This week, the Access to Medicine Foundation, a charity based in the Netherlands, issued its first ranking of 20 pharmaceutical companies' efforts to make key medicines available to the world's poor. The Access to Medicine Index, designed to help investors put their money into companies that are good global citizens, is based on eight criteria, including investment in R&D “that reflects both the global disease burden and neglected diseases,” patenting practices, and commitment to equitable pricing. Top laurels went to GlaxoSmithKline, in part for its recent licensing agreement with a Canadian generics company to manufacture two of its patented antiretroviral drugs for distribution in Rwanda.

  3. The Perfect Crime Gets Harder

    Criminals beware: A scientist at the University of Leicester, U.K., has come up with a way of revealing latent fingerprints on metallic objects such as bullet cartridges and guns.

    Physicist John Bond built on a 2001 discovery that salts from skin can corrode hot metal surfaces, producing an imprint that persists even after the metal is cleaned. Various research groups are exploring ways to reveal these hidden prints, such as heating the metals to spur chemical reactions with the salts.

    In July's Journal of Forensic Sciences, Bond describes a way to detect fingerprints on brass and copper at room temperature. After dusting an object such as a bullet with a black conducting powder, he applies an electric potential that increases the resistivity of the metal at the site of a finger's contact, thus bringing out the image. “Potentially, this will make it possible to reopen old cold cases,” says Bond, who is collaborating with the local police.

    Chemist Neil McMurray of Swansea University in Wales likes the idea but notes that Bond's method won't work if previous examinations of a bullet or gun have disturbed the fingerprints. And, he says, looking for DNA can involve liquid treatments that “will move the salt around.”

  4. Face Genes

    Genetic anthropologist Talal Mohammad based his Ph.D. thesis on tracing the ancestry of Bedouin tribes in the Gulf states, including his native Kuwait. Now he's embarked on a more unusual project: identifying genes that determine facial features in hopes of illuminating how individual differences evolved.

    With start-up funds of $70,000 from International Financial Advisors in Kuwait, Mohammad and colleagues at the University of Cambridge in the U.K. plan to begin next fall by getting cheek swabs from about 500 Kuwaitis. Collaborators at the University of Toronto will fly to Kuwait to do computed tomography scans of their heads. Mohammad says that the team will categorize faces by a list of “landmarks,” which will be compared with up to a million DNA markers. Height, pigmentation, and facial expressions will also be measured. One goal is to test the theory that all humans originated in Africa by comparing modern skulls with ancient ones from the Middle East and Africa.

    Mohammad says Kuwait's homogeneous population should help researchers pinpoint genetic links. He plans to expand the project to other Gulf states, starting with Iran, and ultimately would like to cover the whole world.

    Evolutionary geneticist Chris Tyler-Smith of Cambridge's Sanger Institute (who is not involved in the project) says Mohammad's study marks a departure from past ones that focused solely on the genetics of abnormal features such as those in Down syndrome. “It's a very interesting biological question,” he says. “Why do we all look different, and how are these differences genetically determined?”