Random Samples

Science  22 Jun 2007:
Vol. 316, Issue 5832, pp. 1675
  1. CRUMPLING: A NEW WRINKLE

    Crumpled cream. CREDIT: R. EMMANUEL DE SOUZA/FEDERAL UNIVERSITY OF PERNAMBUCO

    Colleagues of Marcelo A. F. Gomes, a physicist at the Federal University of Pernambuco in Recife, Brazil, can fairly accuse him of skimming the cream off the top in his research. In an unusual experiment, Gomes and his team have studied how films of cream that form on heated milk crumple when they are hoisted from the liquid and set down on a glass plate.

    Even as a child, Gomes says, he was fascinated by the films on his café au lait, which would crumple whenever he tried to pluck them off. Others have studied how paper and polymer sheets crumple, Gomes says, but cream is different: The film is so flimsy it will wad up under its own weight.

    The wads are neither two-dimensional sheets nor three-dimensional solids. By measuring them and peering inside with nuclear magnetic resonance, the researchers found that the wads have a “fractal” dimension of about 2.5, as they report in the 21 June issue of the Journal of Physics D. Because that dimension is the same as that for crumpled paper, the experiment shows that what matters is not how you squash the wads but how their creases and crinkles fit together, says Sahraoui Chaieb, a physicist at the University of Illinois, Urbana-Champaign: “It's all geometry.”

  2. STANDARDIZING STEM CELLS

    Stem cell researchers from around the world have taken a big step toward imposing order on the rapidly spreading landscape of human embryonic stem cell research. In the current issue of Nature Biotechnology, researchers from 17 labs in 11 countries report that they now have comparable data on 59 cell lines.

    The study is part of the International Stem Cell Initiative, headed by Peter Andrews of the University of Sheffield, U.K. “The object was to get everyone to grow cells in as standard conditions as we could,” says Andrews.

    In phase 2 of the initiative, scientists will compare various media for growing cell lines and will analyze gene changes over time—particularly relevant for the lines approved for U.S.-funded researchers, which are the oldest of the lot. A registry, with recipes to enable researchers to obtain comparable data from new cell lines, will be maintained at the Web site of the International Stem Cell Forum, the U.K.-based group that is funding the studies.

  3. DINO DEATH THROES

    Archaeopteryx. CREDIT: C. M. FAUX AND K. PADIAN (2007)/ PALEOBIOLOGY 33: 201-226, FIGURE 1A

    Many fossilized dinosaurs are found in a dramatic death pose: wide-open mouth, thrown-back head, tail twisted over the body. Most scientists have assumed that the posture is caused by events after death. But paleontologists Kevin Padian of the University of California, Berkeley, and Cynthia Marshall Faux of the Museum of the Rockies in Bozeman, Montana, believe it reflects death throes from central-nervous-system trauma.

    “Most traditional interpretations … of the 'dead bird' posture”—such as the effects of drying muscles or water currents—“explain few or no cases,” the authors say. They reached that conclusion after monitoring newly dead birds to see the effects of rigor mortis. They also dried red-tailed hawks for months as their muscles and ligaments shriveled up. In neither case did the pose develop, the authors report in the current (March) issue of Paleobiology. Rather, they suggest other causes such as poisoning or suffocation. They point out that the death pose has been found in dinosaur and bird fossils in northeastern China's Jehol biota, where animals might have been asphyxiated by volcanic gases.

    “I am pleased to see experimental support brought to bear on this question,” says paleobiologist Matthew Carrano of the Smithsonian Institution in Washington, D.C. “I don't think every dinosaur in this pose will necessarily have died in this manner, but [now] we have more possible explanations to choose from.”

  4. NETWATCH: Ill Literacy

    From sickly Tiny Tim in Charles Dickens's A Christmas Carol to the disfigured character in the movie The Elephant Man, illness and its consequences have preoccupied writers, painters, and filmmakers. The Literature, Arts, and Medicine Database aims to help students use these works to understand disease, health care, and the social issues they raise.

    The site from the New York University School of Medicine catalogs hundreds of films, paintings, novels, and other titles with medical connections. Tuberculosis, AIDS, and mental illness have drawn plenty of interest over the years; diabetes and arthritis, much less. Commentaries by guest scholars elucidate works such as Vincent van Gogh's painting of the mental asylum where he spent much of his final year of life. The barren hallway—the only figure is fleeing—reflects his isolation during his illness.

    litmed.med.nyu.edu

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