Does Ganymede have an ocean? Another of Jupiter’s four moons may have had an ocean and may still have it below its surface, according to geological sciences faculty members and James Head and Robert Pappalardo.
Pappalardo, Head and five graduate students and undergraduates looked at the closest images yet of Ganymede. The images of the moon’s Arbela Sulcus region show smooth lanes that look like the sea floor spreading, Head said. The lanes appear to have been pulled apart, similar to mid-ocean ridges on Earth and another Jupiter moon, Europa.
"We were able to see things up close that we were never able to see before," Head said.
The high-resolution images were taken from the spacecraft Galileo, which ventured within 500 miles of the Ganymede surface. Brown students were responsible for picking the areas to examine and figuring out how to take the pictures for the Jet Propulsion Lab in California, which carried out the final commands. Then the Brown team analyzed the "great data" and drew its conclusions, Head said.
They presented their research at the American Geophysical Union meeting in San Francisco in December, where two other teams also presented evidence of a possible ocean. The results have been written about in Science magazine and Science News. — Janet Kerlin
Warning — stressful situation ahead: Given the option, people would rather know when a stressful event is about to occur than not know, according to a study led by Brown researchers whose findings provide insight into the management of panic disorder.
Sixty percent of the study participants expressed a preference to know when an anxiety-provoking event was about to occur. The rest were largely indifferent; only a small percentage preferred not to know. Predictability was especially sought by women with a high vulnerability to anxiety, of whom 90 percent preferred predictability.
"The real value of predictability isn't necessarily when the aversive event is happening," said Carl Lejuez, the study's lead researcher and an assistant research professor of psychiatry and human behavior at Brown. "Predictability allows you to know there are 'safe' periods."
Despite the assumption in clinical work that identifying precipitants to panic is central to cognitive and behavioral treatments for panic disorder, there have been few studies in humans that directly test that assumption, said Lejuez.
Anxiety-provoking events were created by administering participants 20 percent carbon dioxide-enriched air, which produces many of the same psychological and physiological responses people experience during panic attack, including breathlessness, a feeling of tightness in the chest, and sweaty palms.
Forty undergraduate students at West Virginia University without a diagnosed anxiety disorder were tested using air enriched with the CO2.
In the first phase of the study, participants were told that sometimes a tone would warn them CO2 was coming and sometimes there would be no warning. Before each trial, a computer screen displayed either the letter T, indicating that if CO2 were administered during that trial they would hear a tone first, or N, indicating that there would be no tone. In a second phase of the study, participants could chose whether the CO2 would be predictable or unpredictable.
Although only individuals without anxiety disorders were studied, researchers found that study participants with the greatest vulnerability to anxiety (as determined by the way in which they answered a written questionnaire) were more likely to prefer and choose predict-able administrations of CO2 than less vulnerable participants.
In addition, women were twice as likely as men to prefer and choose predictable over unpredictable CO2 administrations. Other studies have found that women are at greater risk for experiencing panic attacks and developing panic disorder, according to Lejuez. Also, women have been shown to be more likely than men to seek information regarding unpleasant events.
Lejuez conducted the research with Michael Zvolensky of Brown, Georg Eifert of West Virginia University and Jerry Richards of the State University of New York-Buffalo. Their findings appeared in the December issue of the American Psychological Association's Journal of Experimental Psychology: Applied. — Kristen Cole
Working upon release from prison: Whether convicted offenders get jobs after they are released from prison, what types of jobs they get, and how long they hold them is part of a new study by John Tyler, assistant professor of education, economics and public policy.
Tyler and colleague Jeff Kling, Princeton University assistant professor of economics, recently received a three-year $154,405 grant to conduct the study "Offender Re-Integration into the Mainstream Labor Market."
They will perform a statistical analysis on everyone who was processed through with the Florida Justice System between 1993 and 2000.
"Given the fact that we’re incarcerating so many people, we’d like to know what the effects are," said Tyler. "This is a question that has not been looked at to such an extent."
America’s rate of imprisonment is the highest in the world, according to a recent analysis by Washington’s nonprofit Sentencing Project. Some 14 million Americans, mostly black and Latino, will spend part of their lives behind bars; about 2 million are currently behind bars.
Tyler and Kling will analyze the effects of factors such as the nature of the arrest, sentence length, and correctional vocational and education programs on various outcomes including recidivism and post-incarceration earnings.
The study is one of a series funded by the Russell Sage Foundation to look at factors associated with the large run-up in the nation’s prison population, said Tyler.
It will combine information from the Florida Department of Corrections, the Florida Department of Law Enforcement, and the Florida Education and Training Placement and Information Program. — Kristen Cole
The mind-body connection: A Brown medical student who took time off from his studies to investigate the basic science of the brain was one of four authors of a recent Science paper that shed light on the link between mind and body.
Ari Blitz and colleagues recorded the activity of individual cells in the prefrontal cortex of monkeys while the animals performed a task that required them to watch objects projected in a darkened room.
The authors found that the pattern of recorded cellular activity reflected how successfully the monkeys performed the task in the past as well as in the future.
Located behind the forehead, the prefrontal cortex is the part of the brain where sensory pathways seem to converge and motor pathways seem to emerge.
"The finding that individual prefrontal cells may reflect complex cognitive activity over time hasn’t been shown quite as clearly before," said the fourth-year student, who conducted the research in 1998 and 1999.
"Single cells reflected in some manner, a process that was neither purely sensory or purely motor, but somewhere in-between. In the future, we may be able to use the findings to model how the brain deals with information over time."
Blitz conducted the research in the Laboratory of Sensorimotor Research at the National Eye Institute in Bethesda, Md. He worked in the lab of Michael Goldberg, M.D., as part of the Howard Hughes Medical Institute—National Institutes of Health Research Scholars Program. The program provides medical students nationwide an opportunity to complete one year of basic science research at the NIH.
In 1999, Blitz presented the findings at the annual meeting of the Society for Neuroscience. He is scheduled to graduate in May, and plans to pursue a career in academic neuroradiology. — Scott J. Turner