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Iceberg computer program is created
STATE COLLEGE, Pa., Dec. 1 (UPI) -- U.S. scientists say they've created a computer program to help predict when icebergs will calve from ice sheets.
"The models we have do not currently have any way to figure out where the big ice sheets end and where the ice calves off to form icebergs," said Penn State Professor Richard Alley.
The problem, he said, is the great variability involved in iceberg calving. One important variable -- the one that accounts for the largest portion of when the iceberg breaks -- is the rate at which ice shelves spread. When ice shelves spread, they crack because of the stresses of spreading. If they spread slowly, the cracks don't propagate through the entire shelf and the shelf remains intact, he said. If the shelf spreads rapidly, the cracks propagate through the shelf, thereby causing calving.
"Spreading explains most of what is observed on the ice sheet," said Alley. "However, the equations come out a little better if we include a few other things."
The researcher determined the basic equation for ice calving is the rate of spreading, times the width of the shelf, times the thickness, times a constant. The researchers said that equation doesn't capture the totality of variation in the ice calving process, but it does account for a large percentage of the variability.
The study appeared in the Nov. 28 issue of the journal Science.
New discovery about T cells is reportedPHILADELPHIA, Dec. 1 (UPI) -- U.S. scientists say they have found a way to keep the body's T cells in prime shape for fighting infection and cancer.
Researchers at the Wistar Institute said they have discovered seven different receptors on the outside of the body's immune system T cells that can "tamp down immune responses during a prolonged battle with an infectious pathogen or against developing cancer."
Assistant Professor E. John Wherry, the study's lead author, said the research also showed the seven receptors likely control different aspects of T cell responses, such as division or expansion and controlling viral replication.
"This amount of control over T cells' response is remarkable," he said. "It suggests that layers of negative regulation exist on exhausted T cells from coexpression of multiple inhibitory receptors. My bet is that these receptors inhibit different aspects of the T cells' response but that the net result of their activation is to turn specific T cell populations off.
"That suggests it may be possible to not only dramatically enhance anti-viral or anti-tumor T cell responses but also to fine tune which response you want to enhance in order to reverse T cell exhaustion and continue fighting an infection or disease."
The new research is reported online in the journal Nature Immunology.
NASA studies pilot cognitionCLEVELAND, Dec. 1 (UPI) -- The U.S. space agency is trying to find an effective way to monitor pilots' brain activity to help stop mishaps caused by stress, fatigue or distraction.
The research being conducted at the National Aeronautics and Space Administration's Glenn Research Center involves using functional near infrared spectroscopy and other imaging technology to measure blood flow in the brain's cortex and the concentration of oxygen in the blood.
NASA said such emerging technology offers a non-invasive, safe, portable and inexpensive method for monitoring indicators of neural activity.
Through the studies, researchers hope to find ways to improve the interaction between the increasingly sophisticated automation being used in aircraft and the humans who operate those aircraft, NASA said. The goal is to aid pilot decision-making to improve aviation safety.
"No matter how much training pilots have, conditions could occur when too much is going on in the cockpit," said Angela Harrivel, a NASA biomedical engineer who is leading the research. "What we hope to achieve by this study is a way to sensitively -- and, ultimately, unobtrusively -- determine when pilots become mentally overloaded."
Diabetes, obesity metabolic link studiedPHILADELPHIA, Dec. 1 (UPI) -- U.S. medical researchers say they have discovered a key molecular partnership that coordinates body rhythms and metabolism.
University of Pennsylvania researchers led by Dr. Mitchell Lazar and doctoral student Theresa Alenghat said they studied a protein called NCoR that modulates the body's responses to metabolic hormones. They said they engineered a mutation in mice that prevents NCoR from working with an enzyme that's normally its partner -- HDAC3. The animals showed changes in the expression of clock and metabolic genes, and were leaner, more sensitive to insulin and on different sleep-wake cycles than controls.
The role of the NCoR-HDAC3 partnership in regulating the body's internal clock was previously unknown, the scientists said. HDAC3 is an enzyme that affects gene expression by binding to receptors in the cell nucleus to affect genes' activity, but not by directly changing DNA.
The researchers said their findings suggest HDAC via NCoR controls the body's internal clock, and, therefore, metabolism, through epigenetic change.
"In the fight against the obesity and diabetes epidemics, disruption of NCoR and its enzyme partner might be a valuable new weapon," said Lazar.
The research is reported in the journal Nature.
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