A Meltdown 10,000 Years Old
The massive West Antarctic Ice Sheet (WAIS) may be headed for a complete meltdown in a process that a new study indicates was triggered thousands of years ago, not as a result of global warming.
Recently, concerns have risen that human-induced climate change could be damaging the Antarctic ice.
But the future of the WAIS "may have been predetermined when the grounding line retreat was triggered in early Holocene time," following the end of the last ice age about 10,000 years ago, a team of scientists led by Howard Conway of the University of Washington reports in the Oct. 8 edition of the journal Science.
The grounding line is the boundary between floating ice and ice thick enough to reach the sea floor, and the scientists found that line has receded about 800 miles since the last ice age, withdrawing at an average of about 400 feet per year for the last 7,600 years.
"It seems like the rate [of melting] that has been going since the early Holocene is similar to the rate right now," Conway said. "Collapse appears to be part of an ongoing natural cycle, probably caused by rising sea level initiated by the melting of the Northern Hemisphere ice sheets at the end of the last ice age."
Continued shrinking of the ice sheet, perhaps even complete disintegration, "could well be inevitable," the report concluded.
The WAIS lies on the section of the continent nearest the tip of South America. It is covered by an ice sheet that extends about 360,000 square miles, approximately equal to the combined areas of Texas and Colorado.
The ice sheet's disappearance is of concern because of estimates that its complete melting could raise the global sea level by 15 to 20 feet, swamping low-lying coastal communities around the world.
At the current rate of melting, that would take about 7,000 years, the researchers estimate. Conway said the melting annually contributes about 1 millimeter--nearly one-twenty-fifth of an inch--to sea-level rise.
While the study indicates global warming is not causing the melting, climate change remains a problem, Conway said. "Global warming could well speed the process. Our study doesn't address that problem."
Eyes for Gays
Some gay people swear they have "gay-dar"--an uncanny ability to sense whether someone else is gay. Now, new research gives a bit of credence to this belief.
Nalini Ambady of Harvard University and colleagues conducted a pair of experiments in which they showed gay and straight men and women short silent videotapes and photographs of gay and straight men and women and asked them to pick who was gay.
Overall, gay men and women were slightly better able than straight people at identifying which people were gay, with gay women being the most accurate, though the differences were very slight.
"These data suggest that gay men and lesbians are similarly accurate; if anything, lesbians' advantage over heterosexual women is relatively greater than gay men's advantage over heterosexual men," the researchers write in the September issue of the Journal of Personality and Social Psychology.
Mice With High Anxiety
In many ways, the life of a mouse must be very stressful. The world is full of dangers--the family cat, those tricky traps. As if life wasn't nerve-racking enough, scientists have created a strain of mice that are fraught with anxiety.
Audrey F. Seasholtz of the University of Michigan Medical School created the mice by deleting a gene that controls production of a protein called corticotropin-releasing hormone (CRH), which is involved in regulating stress.
Male mice without the CRH gene seemed much more anxious--they were less likely to leave a protected chamber or explore open areas, the researchers report in the Sept. 28 issue of the Proceedings of the National Academy of Sciences.
The researchers hope the mice will be useful for testing new anti-anxiety drugs, and could provide new clues to anxiety and stress in humans.
Fire Ants, Still Killing
Fire ants arrived in the United States about 60 years ago and have been marching across the nation ever since, bringing death and misery with them.
The insects' sting can kill, both animals and people. In fact, at least 80 deaths from fire ant stings have been reported in the last decade. Most fire ant attacks have occurred outside. But a handful have occurred inside buildings, including a 5-day-old baby who was attacked in a crib and died, a 2-year-old attacked in his home who suffered eye damage and two older nursing home patients who died.
Now, researchers have reported two more fatalities among elderly nursing home patients. These occurred in two Mississippi nursing homes.
Two elderly patients were found covered with ants, with a trail leading from the floor of their rooms to anthills outside.
"Efforts to eradicate these insects should be undertaken immediately, especially if immobile persons are present," Richard D. deShazo of the University of Mississippi Medical Center writes in the Sept. 21 issue of the Annals of Internal Medicine.