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7:00 pm, Tuesday, March 27, 2007
Auditorium,
Rivermont Collegiate School
Becherer Hall, 1821 Sunset Drive, Bettendorf, Iowa
Directions given below. |
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Special ceremony.
Several student members of Sigma Xi are graduating this spring. In a
brief ceremony preceding the scheduled program, they will be honored
with the presentation of a Sigma Xi cord, to be worn with their
graduation gown on the day of commencement. Each student will bring us
up to date on their plans for the future. We wish them the very best in
their future research projects. |
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Main Event. The public is invited to
join these scientists in discussing some of the top science stories of
2006. After watching three short segments of the NOVA ScienceNow
programs that were broadcast on Oct. 3, 2006 and Nov. 21, 2006, there
will be a panel discussion. Light refreshments will be served.
This program is sponsored jointly by Rivermont Collegiate, the Boston PBS station WGBH and the John Deere Chapter of Sigma Xi, a
national organization of research scientists.
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Asteroid. Scientists discuss the chances of
Apophis, an asteroid detected in 2004, hitting
Earth. They consider the consequences of such an impact,
and how people might prevent or prepare for catastrophic
damage from a powerful asteroid strike.
Dr. Robert Mitchell |
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Mass
Extinction. Researchers believe they have an idea of what
caused the greatest extinction of life ever. The die-off occurred
248 million years ago at the end of the Paleozoic Era's Permian
period, which lasted from 290 to 248 million years ago. The Permian
extinction may have been the result of global warming. In fact, some
scientists think that environmental events, such as ice ages and
extreme warming, might explain several of Earth's five mass
extinctions, all of which occurred in the past 600 million years.
Dr. Bill
Hammer |
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Obesity.
Scientists discuss leptin, a hormone made in the body's fat cells.
Leptin is involved in appetite - when the brain detects low levels of leptin, it causes a person to feel hungry. However, mutations can
interfere with the delivery of leptin's signal to the brain. When
the body produces little or no leptin or when leptin receptors are
nonfunctional, the brain never receives the signal that the body has
sufficient amounts of fat. As a result, the brain continues to
prompt the person to keep eating. Researchers have found that humans
and other animals with low leptin levels or a diminished ability to
detect leptin tend to become obese.
Dr. Heather Mattern |
The panel will be
chaired by Dr. Pam Trotter of the Augustana Chemistry
Department and Program Chair of the John Deere Chapter of Sigma Xi. |
