When good cells go bad; Following water flow
(Editor's Note: Bucknell's Web site is featuring some of the University's newest teacher-scholars. They are among the new faculty members highlighted in the Fall 2007 edition of Bucknell World.)
Like a character in a Gabriel García Márquez novel, Le Paliulis is a woman who travels with a microscope and moths — the greater wax moth, to be exact, and moth larvae, to be more exact.
Paliulis, a geneticist by training and an assistant professor of biology, has been looking at chromosome development in this particular species.
She explains that an odd thing occurs in the greater wax moth: During cell division in what looks like a perfectly normal cell, random and seemingly inexplicable divisions occur during mitosis.
She asks, “How can a cell do these seemingly random divisions when so many checks are in place to make sure it divides properly?” She wonders if this randomness in moths can help explain pathology in human cells. “In a metastatic cancer cell, divisions happen seemingly randomly. Why? What gets messed up? It’s the same thing with these moths. What allows the chromosomes to go wherever they want?”
Paliulis explains that ecological biologists have considered this moth to be a pest for years, but she is the first person to use this moth model to study cell division and look at living cells.
She says, “The fact that I am the only person doing these particular experiments in this organism is so cool.”
One-quarter of the world's population gets its drinking water from karst aquifers, underground water stores characterized by sinkholes, caves, and springs.
“Karst is any topography characterized by bedrock that can dissolve,” says assistant professor of geology Ellen Herman. “In this part of the country, that means limestone and dolomite.”
Herman studies the complex flow of water through these systems of porous rock, thin fractures, and larger conduits, such as caves. During the hurricanes of 2004, Herman and colleagues observed an event rarely documented in karst systems. As Hurricane Ivan followed on the heels of Frances, Arch Spring in Blair County (Pa.) exhibited a threshold – despite higher surface water levels during the second hurricane, the flow in the spring was no higher during Ivan than it had been during Frances.
Because karst systems can't expand over their banks like rivers can, such thresholds were assumed to exist, but Herman was one of the first to document the phenomenon.
Herman also looks at the transport of sediment in karst systems.
Unlike other groundwater systems, the open areas in karst systems allow fast-flowing water to pick up substantial sediment loads. Because pollutants attach themselves to sediments, understanding how sediments move is vital to understanding how pollutants will disperse.
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Posted Nov. 14, 2007
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