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More sprawl means more weight and less walking

Residents of sprawling counties weigh more, walk less in their leisure time and have higher rates of high blood pressure compared with those in more “compact” counties, a new study finds. Reid Ewing, Ph.D., of the National Center for Smart Growth and colleagues say more evidence is needed to pinpoint sprawl as the direct cause of these poor health outcomes. But their findings, appearing in the September/October issue of the American Journal of Health Promotion, suggest a significant association between the form of an urban environment and certain health conditions and behaviors.

White shark attack shows they’re not man-eaters

Shark expert Peter Klimley, a UC Davis researcher, says the recent attack on a swimmer off Avila Pier in Central California supports his belief that adult great white sharks are selective hunters that would rather eat fat seals than bony human beings. Deborah Franzman was swimming at the surface among a group of pinnipeds — seals or sea lions — on Aug. 20 when a great white shark, estimated to be 15 to 18 feet long, grabbed her leg. It stripped the flesh from her left thigh, severing the femoral artery. She was briefly pulled below the surface and then released. When lifeguards reached her a few minutes later, she was facedown in the water. Authorities said she had bled to death.

Black Teen Mothers Have Greater Risk for Low-Birth-Weight Babies

African-American teens are twice as likely to deliver low-birth-weight babies and 1.5 times more likely to have premature babies than whites, according to a new study. The study examined birth outcomes of 1,120 pregnant African-American teens age 17 and younger, living in Baltimore, Md., and compared them to national data on white women. When compared to pregnant black women of all ages in Maryland, the study found the younger group had almost twice the infant mortality rate (2.3 percent vs. 1.3 percent). The study appears in the August 2003 edition of The Journal of Pediatrics.

Rat study shows exposure to Ecstasy early in pregnancy induces brain changes

Researchers have shown that 21-day-old rat pups exposed in the womb to the drug MDMA (3,4-methylenedioxymethamphetamine, often called Ecstasy) during a period corresponding to the first trimester in human pregnancy exhibit changes in brain chemistry and behavior. “Existing data suggest that most women who use MDMA stop taking it when they learn they are pregnant,” says NIDA Director Dr. Nora D. Volkow. “But the animal studies that linked this drug to neurobiological changes and learning impairments were conducted in situations analogous to the third trimester in humans. This study sought to investigate a more true-to-life situation by looking at the consequences of Ecstasy exposure early in pregnancy.”

Stem cells shown to regenerate damaged lung tissue for first time

For the first time, researchers have demonstrated that adult human stem cell transplantation results in spontaneous cell regeneration in damaged lung tissue. Published in the August 1 issue of the American Journal of Respiratory and Critical Care Medicine, the study further supports an existing body of research that suggests blood- and marrow-derived stem cells have the capacity to become many different human tissues.

Analysis doubles previous estimates of Peru killings

AAAS today announced startling new estimates on the number of people who “disappeared” or were killed in Peru during a 20-year battle between government forces and Maoist insurgents that ended in the late 1990s. A final, peer-reviewed version of the AAAS analysis, released today, “doubles earlier, incomplete estimates of how many people were killed,” said Patrick Ball, Deputy Director of the AAAS Science and Human Rights Program. Ball served as co-author of the AAAS report, “How Many Peruvians Died?–An Estimate of the Total Number of Victims of the Internal Armed Conflict, 1980-2000,” along with Jana Asher, a statistical consultant for AAAS, and David Sulmont, with Peru’s Truth and Reconciliation Commission.”

Gene crucial to antibody-producing cell development is key to blood cell cancer

A gene that is crucial to the development and function of an entire family of immune cells is also key to understanding why one member of that family can become cancerous. The researchers had previously shown that one of these cell types, marginal-zone B cells, can give rise to a cancer called mucosa-associated lymphoid tissue (MALT) lymphoma when the cells abnormally over-express a gene called Bcl10. The current finding suggests that a drug that blocks the action of Bcl10 could be an effective treatment for this cancer.

Scientists find key to ocean bacterium that helps control greenhouse gas

Scientists are a step closer to understanding how the world’s oceans influence global warming – as well supply us with the oxygen we breathe. A study led by Imperial College London has revealed how the most abundant ocean bound photosynthetic bacterium helps control levels of the greenhouse gas, carbon dioxide. Reporting in Nature the researchers provide new detail on how Prochlorococcus cyanobacteria traps atmospheric carbon dioxide and stores it in the deep sea.

Nanometer-sized particles change crystal structure when they get wet

As scientists shrink materials down to the nanometer scale, creating nanodots, nanoparticles, nanorods and nanotubes a few tens of atoms across, they’ve found weird and puzzling behaviors that have fired their imaginations and promised many unforeseen applications. Now University of California, Berkeley, scientists have found another unusual effect that could have both good and bad implications for semiconductor devices once they’ve been shrunk to the nanometer scale.

Engineers discover secret of spider, silkworm fiber strength

Bioengineers have discovered how spiders and silkworms are able to spin webs and cocoons made of incredibly strong fibers. The answer lies in how they control the silk protein solubility and structural organization in their glands. “This finding could lead to the development of processing methods resulting in new high-strength and high-performance materials used for biomedical applications, and protective apparel for military and police forces,” said David Kaplan, professor and chair of biomedical engineering, and director of Tufts’ Bioengineering Center.

Supercomputer is fastest open system in U.S.

The Department of Energy’s Pacific Northwest National Laboratory is now home to the United States’ fastest operational unclassified supercomputer. The laboratory’s 11.8 teraflops industry-standard HP Integrity system came to full operating power this week, marking the next advance in high-performance computing designed to enable new insights in the environmental and molecular sciences, including chemistry, biology, climate and subsurface chemistry.

Scientists: Cloak of human proteins gets HIV into cells

Researchers have proposed for the first time that HIV and other retroviruses can use a Trojan horse style of infection, taking advantage of a cloak of human proteins to sneak into cells. The hypothesis explains 20 years of perplexing observations and suggests new ways to reduce HIV transmission and treat HIV infection, but it also implies that existing approaches to developing vaccines against HIV won’t work. A description of the hypothesis and its supporting evidence appear in the Proceedings of the National Academy of Sciences, scheduled for publication online this week.