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TOO MUCH TO BEAR Male births may be another casualty of disasters In the two months following the attacks of September 11, 2001, more male fetuses than usual died in California. Birth weights also decreased and, among those males with low birth weight, 29 percent fewer were born that December. It is one of a group of indicators that public health professor Ralph Catalano calls “communal bereavement.” The unexpected changes that often follow disasters like 9/11 or Hurricane Katrina, he says, may be a sign that we are all dealing with more than we can bear. Trained as an economist, the button-down Catalano is not the kind of guy you’d expect to see around a maternity ward. After decades of studying how changes in the economy can lead to illness, Catalano has identified sensitive tracers of population-wide stress. One is pregnancy. “Pregnant women are biological fortresses. They can cope with a lot. But there is always some fraction of gestations that are on the cusp, and environmental changes can tip them one way or the other,” he says. Increased stress causes increased production of oxytocin in pregnant women, which has a tendency to induce labor prematurely. Male fetuses are thought to be more vulnerable because of the added complexity of producing the “Y” chromosome. By studying California birth and miscarriage records, Catalano and colleagues found that a quarter more male fetuses than expected died in October and November following the 2001 terrorist attacks. The team found the same pattern in New York City. In January 2002 the male-to-female sex ratio was the lowest ever in the 15 years for which data were automated and kept. The number of babies born with very low birth weights also went up. In earlier research, Catalano found that severe economic downturns can also impact sex ratios. After the collapse of East Ger-many’s government and economy in 1991, approximately 800 fewer boys were born than expected, the lowest ratio of male-to-female births since World War II. Determining early indicators of popula-tion stress allows public health workers to intervene sooner and more successfully. “It’s not just gestation that’s affected by environmental stressors,” he says, “It’s heart disease, strokes, depression, and so many other things.” By watching the right numbers, Catalano hopes public health workers can keep more people from becoming statistics. —April Kilcrease
WATCH OUT FOR PEDESTRIANS Electronic sensors help prevent collisions After working in the automotive industry in the late eighties, Ching-Yao Chan M.S. ’85, Ph.D. ’88, learned that even lifesaving technology can be a hard sell. Safety isn’t sexy. “People will pay extra for fancy additions, but they don’t want to pay extra for safety,” says Chan. Chan grew up in Taiwan where, he says, “a red light doesn’t mean anything.” Now an associate research engineer at Berkeley’s Institute of Transportation Studies, he is trying to find the most effective—and affordable—means for saving lives. With a team of researchers and funds from Caltrans, he is focusing on devices for drivers to detect pedestrians. In California in the last five years, over 75,000 collisions involving pedestrians have occurred, resulting in the loss of just over 4,000 lives, most of them in urban areas. As any transit bus driver can tell you, city streets are unpredictable—particularly bus stations and stops where some people are boarding while others are running up from behind or crossing in front of the bus. This makes buses the best candidates for Chan’s pedestrian-detection technology. To keep costs down, the team uses off-the-shelf devices. One promising system uses a microwave radar device installed on a crosswalk signal pole. The device senses pedestrians in the roadway, initiating a wireless warning that alerts the driver with a sound or a message on a display panel.The team’s results will be submitted in February to Caltrans officials. —April Kilcrease FOOL’S GOLD Individual stock traders almost never hit it big In popular mythology, solo investors are modern-day prospectors, searching for investor gold the way 49ers searched for the real thing. Business professor Terrance Odean was one of them. He followed companies carefully and traded actively, always searching for the mother lode. Then he began to study how individual traders actually fare. Individual investors resemble gold-rush prospectors in one unfortunate respect, he found. Much of the wealth they produce ends up in other people’s pockets. The 49ers sacrificed their nuggets to outfitters, ferrymen, and barkeeps. Individual investors often give up their gains to institutions. “You might learn something, and it’s entertaining, but it’s a pretty expensive form of entertainment,” he says. Odean heads Berkeley’s unique interdisciplinary X-Lab, which uses social science methods to answer economic and business questions. His journal articles over the past decade are enough to make readers recoil from the slick Web page of any discount brokerage. In a paper released last July, Odean and two colleagues analyzed every stock trade on the Taiwan stock exchange from 1995 through 1999. Detailed data from the exchange allowed them to distinguish individual investors from institutional ones. Individuals, they found, lost more than $20 million a day—about a third to institutional investors, a third to their brokers, and a third to taxes. During the period they studied, stock trading moved about 2 percent of Taiwan’s gross national product out of the portfolios of individuals and reduced their return by an average of 3.8 percent per year. “That’s the difference between a mortgage at 6 percent and a mortgage at 9.8 percent,” says Odean. While institutions can take the time to study a wide variety of stocks, and apply the same rigor to both purchases and sales, Odean and his collaborators found in a separate study that individuals tend to buy stocks that catch their attention. They use the media as a stock filter, instead of ferreting out companies with the most potential value. But he sees a bright side. “The good news is that you don’t have to go head-to-head with the institutional Investors,” Odean says. “You can buy and hold a well-diversified, low-cost mutual fund and take advantage of the insti-tutional investors’ expertise.” He sees the results as a warning to politicians who want to push more retirement savings into individual investment accounts, and he has written against privatizing Social Security. Odean also follows his own advice. “I quit actively trading about 12 years ago,” he says. —Steven Bodzin RECOVERING MEMORY Is the aging brain too distracted to remember? Comedian Steve Martin tells this joke about memory loss after age 50: “Put your car keys in your right hand. With your left hand call a friend,” he instructs. “Then hang up the phone. Now, look for your keys.” Martin also has a theory about why you forget. The brain is too full, he says, which explains that while you can’t find your keys, you can still remember your third-grade teacher’s name and the lyrics to “Volare.” Silly as the theory sounds, a team led by neuroscientist Adam Gazzaley recently conducted an experiment that suggests there’s something to it. We forget, he argues, because as we get older, our brains often lose the capacity to filter out distractions. “When a fire engine goes by, it can disrupt everything going on around you,” he explains. For some older people, ordinary sights and sounds have the same effect as a fire engine. Without the ability to block out distractions, our short-term memory becomes overloaded and we fail to remember recent information—like where we put the keys. In the experiment, Gazzaley’s team first identified markers in the brain for focusing and suppressing information. They then performed a simple memory test on two groups: one, ages 19 to 30, and one, ages 60 to 77. As they lay in an fMRI scanner, the subjects were flashed a sequence of four images—two faces and two scenic shots (taken by Gazzaley, an avid nature photographer). Afterward, they were instructed to remember either just the faces or the nature scenes. Both groups could focus on one image. But the older group had less ability—or none at all—to avoid being distracted by the other images. The degree to which they could suppress the distracting images correlated with how well they could recall the images they were asked about. Encouragingly, six of the 16 older adults had no problems ignoring the irrelevant pictures, suggesting that some people are able to avoid memory loss as they age. Gazzaley will now try to discover what makes these people different from the average aging adult. Gazzaley, a fit 36-year-old, admits he’s a man on a mission. He hopes that the findings will lead to more effective “brain exercises” and drug treatments that target problems with suppressing distractions. He also plans to test the common Alzheimer’s medication Donepezil on healthy older individuals to see if it could correct this suppression deficit and restore memory performance to a young adult level. “It would be nice to beat the clock and figure out how to fix the problem before I get there,” he says. —April Kilcrease GOT BEES? How urban gardeners can help reverse the pollinators’ decline When a fellow entomologist stopped by Gordon Frankie’s office in 1998, the College of Natural Resources professor—and campus bee expert—couldn’t know that the visit would change the course of his research. His friend bore a wooden box filled with six bee species he had caught on Albany Hill, not far from the Cal campus. “I had no idea that there was that kind of diversity,” Frankie recounts, still seemingly in awe. The next day, Frankie returned to the same spot, caught nine bee species in two hours, and got hooked on urban bees. The discovery that the often-maligned insects were thriving in the residential Bay Area was an environmental epiphany for Frankie. A veteran scholar of wildland bees in Costa Rica and California, he knew that pollinators were in massive decline worldwide. Although one-third of the world’s produce supply depends on pollination, threats such as urban sprawl, pesticides, and modern agricultural practices have put pollinators in peril. The United States hosts half as many managed honeybees compared to 50 years ago. To Frankie, the message is clear: If gardeners encourage bees to visit their yards, urban bees will have a built-in habitat to count on. The connection is especially important for gardeners who grow fruits and vegetables. “There’s a reason why the food happens—it’s the bees,” Frankie says, sporting a blue Hawaiian shirt splashed with pastel flowers. “You’re not going to get a strawberry if you don’t have bees.” Frankie and his research team have identified 82 bee species in Berkeley alone. With a special campus bee garden for observing the insects’ behavior, and a statewide bee-collection drive, he hopes the gardening public can gain insight from his studies. The most important thing gardeners can do, Frankie suggests, is provide bees a variety of plants to visit. Old favorites such as sunflowers, honey-suckle, wild lilac, and poppies are bee magnets. Many others are identified on the project’s Web site. Gardens with 10 or more bee-friendly plants are the most attractive to bees; they can sample one flower and then hop to the next. For further information, go to: http://nature.berkeley.edu/urbanbeegardens. —Lygia Navarro
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