Saturday, December 12, 2009

'SMELL OF OLD BOOKS' OFFERS CLUES TO HELP PRESERVE THEM

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Scientists may not be able to tell a good book by its cover, but they now can tell the condition of an old book by its smell. In a report in ACS' Analytical Chemistry, a semi-monthly journal, they describe development of a new test that can measure the degradation of old books and precious historical documents based on their smell. The nondestructive "sniff" test could help libraries and museums preserve a range of prized paper-based objects, some of which are degrading rapidly due to advancing age, the scientists say.

Matija Strlic and colleagues note in the new study that the familiar musty smell of an old book, as readers leaf through the pages, is the result of hundreds of so-called volatile organic compounds (VOCs) released into the air from the paper. Those substances hold clues to the paper's condition, they say. Conventional methods for analyzing library and archival materials involve removing samples of the document and then testing them with traditional laboratory equipment. But this approach destroys part of the document.

The new technique, called "material degradomics," analyzes the gases emitted by old books and documents without altering the documents themselves. They used it to "sniff" 72 historical papers from the 19th and 20th centuries, including papers containing rosin (pine tar) and wood fiber, which are the most rapidly degrading paper types in old books. The scientists identified 15 VOCs that seem good candidates as markers to track the degradation of paper in order to optimize their preservation. The method also could help preserve other historic artifacts, they add.

(Photo: Wikimedia Commons)

American Chemical Society

IN CO2-RICH ENVIRONMENT, SOME OCEAN DWELLERS INCREASE SHELL PRODUCTION

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In a striking finding that raises new questions about carbon dioxide’s (CO2) impact on marine life, Woods Hole Oceanographic Institution (WHOI) scientists report that some shell-building creatures—such as crabs, shrimp and lobsters—unexpectedly build more shell when exposed to ocean acidification caused by elevated levels of atmospheric carbon dioxide (CO2).

Because excess CO2 dissolves in the ocean—causing it to “acidify” —researchers have been concerned about the ability of certain organisms to maintain the strength of their shells. Carbon dioxide is known to trigger a process that reduces the abundance of carbonate ions in seawater—one of the primary materials that marine organisms use to build their calcium carbonate shells and skeletons.

The concern is that this process will trigger a weakening and decline in the shells of some species and, in the long term, upset the balance of the ocean ecosystem.

But in a study published in the Dec. 1 issue of Geology, a team led by former WHOI postdoctoral researcher Justin B. Ries found that seven of the 18 shelled species they observed actually built more shell when exposed to varying levels of increased acidification. This may be because the total amount of dissolved inorganic carbon available to them is actually increased when the ocean becomes more acidic, even though the concentration of carbonate ions is decreased.

“Most likely the organisms that responded positively were somehow able to manipulate…dissolved inorganic carbon in the fluid from which they precipitated their skeleton in a way that was beneficial to them,” said Ries, now an assistant professor in marine sciences at the University of North Carolina. “They were somehow able to manipulate CO2…to build their skeletons.”

Organisms displaying such improvement also included calcifying red and green algae, limpets and temperate urchins. Mussels showed no effect.

“We were surprised that some organisms didn’t behave in the way we expected under elevated CO2,” said Anne L. Cohen, a research specialist at WHOI and one of the study’s co-authors. “What was really interesting was that some of the creatures, the coral, the hard clam and the lobster, for example, didn’t seem to care about CO2 until it was higher than about 1,000 parts per million [ppm].” Current atmospheric CO2 levels are about 380 ppm, she said. Above this level, calcification was reduced in the coral and the hard clam, but elevated in the lobster

The “take-home message, “says Cohen, is that “we can’t assume that elevated CO2 causes a proportionate decline in calcification of all calcifying organisms.” WHOI and the National Science Foundation funded the work.

Conversely, some organisms—such as the soft clam and the oyster—showed a clear reduction in calcification in proportion to increases in CO2. In the most extreme finding, Ries, Cohen and WHOI Associate Scientist Daniel C. McCorkle exposed creatures to CO2 levels more than seven times the current level.

This led to the dissolving of aragonite—the form of calcium carbonate produced by corals and some other marine calcifiers. Under such exposure, hard and soft clams, conchs, periwinkles, whelks and tropical urchins began to lose their shells. “If this dissolution process continued for sufficient time, then these organisms could lose their shell completely,” Ries said, “rendering them defenseless to predators.”

“Some organisms were very sensitive,” Cohen said, “some that have commercial value. But there were a couple that didn’t respond to CO2 or didn’t respond till it was sky-high—about 2,800 parts per million. We’re not expecting to see that [CO2 level] anytime soon.”

The researchers caution, however, that the findings—and acidification’s overall impact—may be more complex than it appears. For example, Cohen says that available food and nutrients such as nitrates, phosphates and iron may help dictate how some organisms respond to carbon dioxide.

“We know that nutrients can be very important,” she says. “We have found that corals for example, that have plenty of food and nutrients can be less sensitive” to CO2. “In this study, the organisms were well fed and we didn’t constrain the nutrient levels.

“I wouldn’t make any predictions based on these results. What these results indicate to us is that the organism response to elevated CO2 levels is complex and we now need to go back and study each organism in detail.”

Ries concurs that any possible ramifications are complex. For example, the crab exhibited improved shell-building capacity, and its prey, the clams, showed reduced calcification. “This may initially suggest that crabs could benefit from this shift in predator-pray dynamics. But without shells, clams may not be able to sustain their populations, and this could ultimately impact crabs in a negative way, as well,” Ries said.

In addition, Cohen adds, even though some organisms such as crabs and lobsters appear to benefit under elevated CO2 conditions, the energy they expend in shell building under these conditions “might divert from other important processes such as reproduction or tissue building.”

Since the industrial revolution, Ries noted, atmospheric carbon dioxide levels have increased from 280 to nearly 400 ppm. Climate models predict levels of 600 ppm in 100 years, and 900 ppm in 200 years.

“The oceans absorb much of the CO2 that we release to the atmosphere,” Ries says. However, he warns that this natural buffer may ultimately come at a great cost.

“It’s hard to predict the overall net effect on benthic marine ecosystems," he says. “In the short term, I would guess that the net effect will be negative. In the long term, ecosystems could re-stabilize at a new steady state.

“The bottom line is that we really need to bring down CO2 levels in the atmosphere.”

(Photo: Tom Kleindinst, Woods Hole Oceanographic Institution)

Woods Hole Oceanographic Institution

FACEBOOK PROFILES CAPTURE TRUE PERSONALITY

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Online social networks such as Facebook are being used to express and communicate real personality, instead of an idealized virtual identity, according to new research from psychologist Sam Gosling at The University of Texas at Austin.

"I was surprised by the findings because the widely held assumption is that people are using their profiles to promote an enhanced impression of themselves," says Gosling of the more than 700 million people worldwide who have online profiles. "In fact, our findings suggest that online social networking profiles convey rather accurate images of the profile owners, either because people aren't trying to look good or because they are trying and failing to pull it off.

"These findings suggest that online social networks are not so much about providing positive spin for the profile owners," he adds, "but are instead just another medium for engaging in genuine social interactions, much like the telephone."

Gosling and a team of researchers collected 236 profiles of college-aged people from the United States (Facebook) and Germany (StudiVZ, SchuelerVZ). The researchers used questionnaires to assess the profile owners' actual personality characteristics as well as their ideal-personality traits (how they wished to be). The personality traits included: extraversion, agreeableness, conscientiousness, neuroticism and openness.

In the study, observers rated the profiles of people they did not know. These ratings were then compared to the profile owners' actual personality and their ideal-personality. Personality impressions based on online social network profiles were accurate and were not affected by profile owners' self-idealization.

Accuracy was strongest for extraversion — paralleling results of face-to-face encounters — and lowest for neuroticism. Those findings were consistent with previous research showing that neuroticism is difficult to detect without being in person.

"I think that being able to express personality accurately contributes to the popularity of online social networks in two ways," says Gosling. "First, it allows profile owners to let others know who they are and, in doing so, satisfies a basic need to be known by others. Second, it means that profile viewers feel they can trust the information they glean from online social network profiles, building their confidence in the system as a whole."

Gosling recently co-authored a study on how first impressions do matter when it comes to communicating personality through appearance. For his latest personality research, he focuses his attention to personality in relation to online social networks.

The University of Texas at Austin

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