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Warming Seas Drive Rapid Acceleration of Melting Antarctic Ice

As warm ocean water rises up to melt them, glaciers around the Amundsen Sea are losing half a Mount Everest a year.

A second study, published Thursday in the journal Science, helps explain the accelerating ice melt: Warm ocean water is melting the floating ice shelves that hold back the glaciers.

The two new pieces of research come as officials of the World Meteorological Organization announced Wednesday that 2014 is on track to be the warmest year on record.

Scientists have long worried that the West Antarctic ice sheet is a place where climate change might tip toward catastrophe. The ice sheet holds enough water to raise sea level by 16 feet (5 meters). The region along the Amundsen Sea is the sheet’s soft underbelly, where the ice is most vulnerable. (See “Rising Seas” in National Geographic magazine.)

Earlier this year, researchers at the University of California, Irvine and NASA’s Jet Propulsion Laboratory reported that the glaciers flowing into the Amundsen Sea—notably the Pine Island and Thwaites Glaciers—were already doomed to collapse, and at the current rate of melting would be gone in 200 years.

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Caffeine helps your memory

Caffeine is the energy boost of choice for millions who consume it to wake up or stay up. Now, UC Irvine neurobiologist Michael Yassa has found another use for the stimulant: memory enhancer.

Michael Yassa, assistant professor of neurobiology & behavior, and his team of scientists found that caffeine has a positive effect on long-term memory in humans.

“We’ve always known that caffeine has cognitive enhancing effects, but its particular effects on strengthening memories and making them resistant to forgetting has never been examined in detail in humans,” Yassa said. “We report for the first time a specific effect of caffeine on reducing forgetting over 24 hours.”

The researchers conducted a double-blind trial in which participants who did not regularly eat or drink caffeinated products received either a placebo or a 200 milligrams caffeine tablet five minutes after studying a series of images. Saliva samples were taken from the participants before ingesting caffeine, and one, three and 24 hours afterwards to check for increased caffeine levels.

The next day, both groups were tested on their ability to recognize images from the previous day’s study session. On the test, some of the visuals were the same as from the day before, some were new additions and some were similar but not the same as the items previously viewed. Researchers say more participants in the caffeine group were able to correctly identify the new images as “similar” to previously viewed images versus erroneously citing them as the same.

The brain’s ability to recognize the difference between two similar but not identical items, called pattern separation, reflects a deeper level of memory retention, the researchers said.

“If we used a standard recognition memory task without these tricky similar items, we would have found no effect of caffeine,” Yassa said. “However, using these items requires the brain to make a more difficult discrimination – what we call pattern separation, which seems to be the process that is enhanced by caffeine in our case.”

[Image via yourcoffeeguru]

Read the rest of the most discussed UC research of 2014 →

West Antarctic glacier loss appears unstoppable

A rapidly melting section of the West Antarctic Ice Sheet appears to be in irreversible decline, with nothing to stop the entire glacial basin from disappearing into the sea, according to researchers at UC Irvine and NASA.

The new study presents multiple lines of evidence — incorporating 40 years of observations that six massive glaciers in the Amundsen Sea sector “have passed the point of no return,” according to glaciologist Eric Rignot, a UC Irvine Earth system science professor who is also with NASA’s Jet Propulsion Laboratory. The new study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

These glaciers already contribute significantly to sea level rise, releasing as much ice into the ocean each year as the entire Greenland Ice Sheet does. They contain enough ice to boost the global sea level by 4 feet (1.2 meters) and are melting faster than most scientists had expected. Rignot said the findings will require that current predictions of sea level rise be revised upward.

“This sector will be a major contributor to sea level rise in the decades and centuries to come,” Rignot said. “A conservative estimate is that it could take several centuries for all of the ice to flow into the sea.”

Three lines of evidence

Three major lines of evidence point to the glaciers’ eventual demise: changes in their flow speeds, how much of each glacier floats on seawater, and the slope and depth below sea level of the terrain they’re flowing over. In a paper published last month, the research group showed that the speed at which the glaciers are moving has accelerated steadily for four decades, increasing the amount of ice draining from them by 77 percent from 1973 to 2013. This new study focuses on the other two lines of evidence.

The West Antarctic glaciers flow out from land over the ocean, with their front edges afloat. The point at which they lose contact with land is called the grounding line. Virtually all glacial melting occurs on the undersides of their floating sections — beyond the grounding line.

Just as a boat that’s run aground can float again if its cargo is unloaded, a glacier can float over an area where it used to be grounded if it becomes lighter, which it does by melting or by stretching out and thinning. The Antarctic glaciers studied by Rignot’s group have shrunk so much that they’re now floating above places where they used to sit solidly on land, which means the grounding lines are retreating inland.

They’re “buried under a thousand or more meters of ice, so it’s incredibly challenging for a human observer on the ice sheet surface to figure out exactly where the transition is,” Rignot said. “This analysis is best done via satellite techniques.”

The team used radar observations from the European Remote Sensing satellites (ERS-1 and ERS-2) between 1992 and 2011 to map the grounding lines’ inland creep. The satellites employ a method called radar interferometry that enables scientists to measure very precisely — within a quarter of an inch — how Earth’s surface is moving. Glaciers shift horizontally as they flow downstream, but their floating portions also rise and fall with changes in the tides. Rignot and his group mapped how far inland these vertical motions extend to locate the grounding lines.

Vicious cycle

The accelerating flow speeds and retreating grounding lines reinforce each other in a recurring loop. As glaciers move faster, they stretch out and thin, which decreases their weight and lifts them farther off the bedrock. As the grounding line retreats and more of the glacier becomes waterborne, there’s less resistance underneath, so the flow accelerates, and so on — with each action intensifying the next.

Slowing or stopping these changes requires “pinning points” — bumps or hills rising from the glacier bed that snag the ice from below. To locate them, researchers produced a more accurate map of bed elevation that combines ice velocity data from ERS-1 and ERS-2 and ice thickness data from NASA’s Operation IceBridge mission and other airborne campaigns. The results confirmed that just one pinning point remains upstream of the current grounding lines. Only Haynes Glacier has major bedrock obstructions upstream, but it drains a small sector and is retreating as rapidly as the other glaciers.

Bed topography is another key to the fate of the ice in this basin. All the glacier beds slope deeper below sea level as they extend inland. As they retreat, they cannot escape the ocean’s reach, and the relatively warm water melts them even more rapidly.

The accelerating flow rates, lack of pinning points and sloping bedrock all point to one conclusion, Rignot said:

“The collapse of this sector of West Antarctica appears to be unstoppable. The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating parts of the glaciers. At this point, the end appears to be inevitable.”

Starting From the Bottom: Why Mexicans are the Most Successful Immigrants in America

Photo by Gareth Davies

A new study from UC Irvine and UCLA challenges our definition of success.

Who’s more successful: The child of Chinese immigrants who is now a prominent attorney, or a second-generation Mexican who completed high school and now holds a stable, blue collar job?

The answer depends on how you define success.

In fact, according to a study by University of California, Irvine, Sociology Professor Jennifer Lee and UCLA Sociology Professor Min Zhou, contrary to stereotypes, Mexican-Americans are the most successful second-generation group in the country. The reason is simple: The study considered not just where people finished, but from where they started.

The report serves as counter-point to arguments raised by Amy Chua, a Yale Law School professor better known as the Tiger Mom. In a new book, The Triple Package, Chua and her husband, Jed Rubenfeld, argue that some groups—namely Chinese, Jews, Cubans, and Nigerians—are more successful than others because they possess certain cultural traits that enable them to be.

In a nutshell, Chua’s “Triple Package” includes: a cultural superiority complex, impulse control, and insecurity. Combined, the authors assert, these traits drive the groups to succeed within a broader American culture that is comparatively lackadaisical. They base their argument on an analysis of test scores, educational achievement, median household income, and other factors.

The UC study, however, argues that it’s not any specific cultural trait that makes groups like Chinese-Americans more successful than others. Lee and Zhou say both Chinese-American and Mexican-American parents highly value education. Most parents do. But the reason Chinese-Americans get ahead is because they start ahead. Way ahead, in many cases.

The study, called “The Success Frame and Achievement Paradox: The Cost and Consequences for Asian-Americans,” looked at Chinese-, Vietnamese-, and Mexican-Americans in Los Angeles whose parents immigrated to the U.S. At first glance, the study’s findings seem to reinforce claims made by Chua and her supporters: Children of Chinese immigrants far exceeded other groups when it came to educational outcomes. Sixty-four percent of Chinese immigrants’ children graduated from college, compared to 46 percent of native-born whites in L.A. Of the Chinese-American college graduates, 22 percent went on to attain graduate degrees.

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