Spotlight on Research -- Mason Gazette

September 2001
		Spotlight on Research Sambruna Receives NASA Grant for Black Hole Research Rita Sambruna, assistant professor in Physics and Astronomy and the School of Computational Sciences, was awarded $550,000 from the National Aeronautics and Space Administration (NASA) to support her extragalactic astrophysics research on black holes. The five-year grant comes from NASA's highly competitive Long-Term Space Astrophysics (LTSA) program. Sambruna plans to use the funds primarily to hire a postdoctoral fellow to join her research group. The research continues work involving NASA's Chandra X-ray Observatory, which she began while a research associate at Pennsylvania State University. "We are studying what happens to material that falls near a black hole. When we look at a quasar or a galaxy with a large black hole in the center, we often see a lot of emissions of x rays and gamma rays. This high-energy radiation is particularly important because it comes from the inner regions of the accretion disk very close to the black hole," explains Sambruna. Under the grant, Sambruna plans to use the data to understand the structure of the inner accretion disk using state-of-the-art models. The particular class of objects she is studying are called radio-loud active galactic nuclei, which shoot out jets of plasma at speeds very close to the speed of light. Sambruna says that astrophysicists still do not understand why and how these jets are formed. "So by studying the structure of the accretion disk near the black hole, we actually hope to learn more about the formation of the jet," she explains. "This research is timely because we have a lot of new instruments up in space that allow us to capture world-class data," says Sambruna. The data primarily are gathered by Chandra and a European spacecraft, XMM-Newton. She also will tap into archived data from past x-ray missions. —Lynn Burke PIA Gets $1.49 Million to Study Civic Health The Department of Public and International Affairs (PIA) received a $1.49 million grant by the Pew Charitable Trusts for a two-year project to study and track the level of civic engagement among the U.S. public, with a focus on young people ages 15 to 22. The Pew Charitable Trusts support nonprofit activities in the areas of culture, education, the environment, health and human services, public policy, and religion. George Mason will lead Rutgers University, Loyola University of Chicago, and the University of California at Berkeley in the project, which aims to develop a new set of indicators of civic engagement, with special attention to the political involvement of youth. Researchers and civic organizations could then use the indicators to monitor the state of the nation's civic health and assess the effectiveness of programs aimed at improving civic participation. Scott Keeter, PIA chair, will direct the project. PIA will create a new center for the study and for promotion of civic engagement. The center also will house PIA's other citizenship activities, including the university's partnership with the Virginia Citizenship Institute. According to Keeter, "Fewer Americans of all ages are participating in politics today, compared with 30 years ago, but the trend is especially troubling for young people. While younger citizens have always been less active than their elders, the gap between young and old has greatly expanded in recent years and has become a vast generational chasm." —Jeremy Lasich Researchers Detect Antibiotic-Resistant Bacteria in Md. River Researchers in the Shared Research Instrumentation Facility (SRIF) have found antibiotic-resistant bacteria in Maryland's Pocomoke River, which could be a cause for concern for those who enjoy recreational water sports in the area. The university's interest in the Pocomoke, part of the Chesapeake Bay watershed, began several years ago when the river was experiencing massive fish kills, which at the time were attributed to the organism Pfisteria. "This interested us so we began doing what we could to see if we could come up with any answers for what's going on in that vicinity," says Tom Huff, SRIF lab manager. "What we are finding, along with many other people, is that it's a very sick river. "Part of the problem is that the river's ecology has been turned on its head," says Huff. The river is right in the middle of a major poultry-producing region, he explains, and the farmers don't have an adequate way to deal with all the manure. Typically, the nutrient-rich manure is composted and then spread on nearby fields. When it rains, anything in the manure ends up in the runoff that eventually reaches the river. The resistant bacteria that SRIF researchers have found may indicate that antibiotics, which are given to the chickens in therapeutic doses in their feed, are persisting in their manure and ending up in the Pocomoke. Along with killing off bacteria that is beneficial to the ecosystem, antibiotics also cause problems when they come in contact with potentially harmful bacteria that can withstand low doses of antibiotics. "The ones that don't die continue to reproduce, and you end up with a large population of bacteria that has developed a resistance to specific antibiotics, and that's when things start to go wrong," says Huff. When you have a recreational area like the Chesapeake Bay, if a boater, water skier, or swimmer has a cut and goes into the water, he or she can be infected by this resistant bacteria and the usual cure--antibiotics--won't be of much help, he adds. According to Jenefir Isbister, a research professor in SRIF and George Mason's Center for Bioresource Development, many antibiotics are not degraded when they enter the environment or come through a wastewater treatment plant. The research team will be looking at how different land-use practices affect the number and diversity of microbes in the water. For instance, says Isbister, chicken farms use a lot of sulfanomides and that's where the team found bacteria resistant to sulfanomides; near an aquaculture facility where a lot of tetracyclines are used, they found bacteria resistant to tetracyclines. "Our interest is to look and see what types of antibiotics are in the water and the sediment to get an idea of what's going on. The problem is that it hasn't been done that often," says Huff. Methods for determining how much of the common pollutants--such as pesticides, PCBs, dioxins--have been developed, he says. "The problem with antibiotics is that the methods are not in existence yet." According to Huff, several groups are making progress, but, at this point, no one can sample water or sediment and tell you all the antibiotics in the sample. Part of the SRIF research is to develop methods to test for a large number of antibiotics. The researchers are approaching this task in two ways: the SRIF microbiologists look for bacteria resistant to specific antibiotics, and the SRIF chemists confirm the presence of those antibiotics and determine their concentration in the environment. They hope their research will shed light on the problems that have plagued the Pocomoke River and many other Chesapeake Bay tributaries in recent years. —Lynn Burke