Thursday, December 14, 2006

Laughter: it's catching - Nature

Published online: 12 December 2006; | doi:10.1038/news061211-7

Happy sounds tickle the brain to prompt a smile.

Ned Stafford

The automatic trigger to laughter helps people to build strong bonds with each other.

Laughter is indeed infectious, according to a new study. Researchers have shown that the mere sound of giggles tickles the same area of the listener's brain that is activated when smiling. The brain's response helps to prepare the facial muscles for a good hearty laugh.

"It really seems to be true: 'Laugh and the whole world laughs with you'," says study co-author Sophie Scott, a neuroscientist at University College London in the United Kingdom.

The team of played pleasant sounds, such as laughter or cheering, and unpleasant sounds, such as screaming or retching, to volunteers. They then monitored their brains with functional magnetic resonance imaging (MRI). All the sounds triggered neural responses in the premotor cortex of the brain — an area known to prepare groups of facial muscles to respond accordingly. When a person in the study actually smiled or laughed, the neural activity moved to a primary motor cortical region.

The neural response in the premotor cortex was, on average, twice as big for pleasant sounds than for unpleasant sounds, the team reports. Since the pleasant sounds have a bigger impact on the bit of the brain that activates muscles to respond in kind, the findings suggests that pleasant sounds are more 'contagious' than unpleasant ones. The research is published this week in the Journal of Neuroscience1.

Helpless mimicry

Scott says that these results are significant because they suggest that the laughter-triggering mechanism in the human brain is "very basic or automatic": that people are essentially helpless to control the impulse to smile or laugh when they hear pleasant sounds. A good example of this, she says, is when people in a boring meeting strenuously try to suppress the urge to giggle. As soon as one person finally emits a squeak, the whole meeting can erupt into a laugh-fest.

Humans are already known to mirror the habits or emotions of those around them, Scott says. Friends often start using the same words, assuming similar postures, and mimicking hand gestures. And the contagiousness of a good or bad mood is well known. Scott says the neural response in the brain, which automatically primes people who hear pleasant sounds to smile or laugh, is another form of mirroring behaviour that helps people to interact socially and to build strong bonds with each other.

"We usually encounter positive emotions, such as laughter or cheering, in group situations," she explains.

Forcing a smile

The work fits in with previous studies that have illustrated the link between simple stimuli and more complex emotions or feelings. Forcing a smile can actually lift a person's mood2. And stimulating some bits of the brain has been shown to actually prompt laughter in at least one patient3.

As the mother of a 5-month-old baby boy, Scott says that she gets a lot of first-hand experience of this trigger mechanism. A grin from any one of her family tends to set all the others off, she says.

But while Scott's baby smiles back when smiled at, he doesn't yawn back after a tired yawn from mom, she says. Scott's team didn't include sounds or pictures of yawns in their study, but she would be interested to see how and why that action is contagious too.

Wednesday, December 13, 2006

Arctic clear for summer sailing by 2040 - Nature

Published online: 11 December 2006; | doi:10.1038/news061211-1

Models predict rapid decline of sea ice.

Amanda Leigh Haag

September arctic ice-cover could be reduced from 6 million to 2 million square kilometres in just one decade.

New climate simulations offer a dire forecast for the disappearance of Arctic sea ice, predicting that by the year 2040, the Arctic Ocean will be almost free of ice during late summer.

Some projections from climate centres worldwide have suggested previously that Arctic sea ice could vanish in September, at the end of the summer melt, by as early as 2050. But the most recent calculations, performed on the Community Climate System Model at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, predict the most rapid and imminent decline yet.

Models differ in their assumptions of how sensitive Arctic ice is to warming air and water temperatures at different times of year. "We're in the more sensitive bracket among models, but we're not an outlier by any means," says Cecilia Bitz, an atmospheric scientists at the University of Washington and a co-author of the study.

The research team, led by Marika Holland, based at NCAR, modeled fluctuations in the sea ice since 1870 using seven distinct simulations. Their work, published this week in Geophysical Research Letters, indicates that in one scenario, September ice-cover could be reduced from 6 million to 2 million square kilometres in just one decade. About 20% of present-day ice cover would remain. But most of this ice would hug the coasts of Canada and Greenland, leaving the Arctic Ocean nearly free of ice at the end of summer.

Across all the seven simulations, which closely match scientists' observations of actual sea ice disappearance up to the present, the latest that the summer ice is expected to disappear is by 2055.

We're losing ice on both ends of the seasons.

Mark Serreze, National Snow and Ice Data Center.
Freeze and thaw

Sea ice waxes and wanes seasonally. The ice pack melts throughout the warm, summer months, usually reaching its minimum thickness and extent in the first two weeks of September. In autumn and winter, as the Arctic deep freeze sets in, the ice is replenished to an annual average of some 15 million square kilometers, blanketing the Arctic Ocean. The thickness and extent of sea ice at summer's end play an important role in the formation of ice the following winter.

For five straight years now, the ice cover has dipped well below average during the summer months, with 2005 setting a record minimum for September ice: Arctic sea ice dropped 20%, or 1.3 million square kilometres, below the 1979-2000 average. This loss equals roughly twice the size of the state of Texas. (September 2006 was expected to set another record in sea ice loss, but an unseasonably cool August stopped it from doing so.) The trend over the past five years translates to an 8% loss in sea ice each decade.

One of the reasons for this potentially dramatic decline in sea ice cover is what climate scientists refer to as a feedback in the climate system known as the 'albedo effect': ice reflects more sunlight than dark, open water and serves as an insulator to the warmer ocean below it. As the ice pack shrinks and thins in the summertime, the insulating effect is weakened and the dark waters below store more heat, further accelerating the ice melt.

Losses at both ends

The increased summer thaw is having an impact on the winter ice cover too. Over the past two winters, the area of sea ice has fallen by 6% per year, compared with an average of 1.5% per decade since 1979, according to NASA.

"The recovery in autumn is no longer what it once was," says Mark Serreze, a sea ice expert with the National Snow and Ice Data Center in Boulder. "What we're starting to see now is that we're losing ice on both ends of the seasons."

All this should open passage for ships and submarines wishing to traverse the Arctic Ocean, at least in summer. It also means a loss of habitat for polar bears, as the winter ice becomes too thin to support their weight as they travel long distances. And plankton that thrive in icy conditions and provide the base of the food chain may not be suited to ice-free conditions.

Serreze notes that while climate model predictions vary on timescales for the disappearance of summer sea ice, "these climate models are in near universal agreement that as the climate warms in response to greenhouse gas loading, we're going to lose the Arctic sea ice cover."

Thursday, December 07, 2006

Extrasolar planet - Wikipedia

It's fun to notice the embarrassment of the author when mentioning the existence of "Planetary Mass Objects". The restrictive definition of a planet leads scientists to find weird words for simple things. If an "object" - that looks like a planet - is not orbiting a star, it is forbidden to call them "planets". Sorry for them.


An extrasolar planet, or exoplanet, is a planet beyond the Solar System (i.e., orbits a star other than the Sun.) As of 11 November 2006, 209 extrasolar planets have been discovered (see list of stars with known extrasolar planets).[1]

Known exoplanets are members of planetary systems that orbit a star. There have also been unconfirmed reports of free-floating planetary-mass objects ("rogue planets": that is, ones that do not orbit any star). Since such objects do not satisfy the working definition of "planet" adopted by the International Astronomical Union, and since their existence remains unconfirmed, they will not be discussed in this article.[2] For more information, see interstellar planet.

Infrared image of 2M1207 (blue) and its planet 2M1207b, as viewed by the Very Large Telescope. As of September 2006 this is the only confirmed extrasolar planet to have been directly imaged.
Infrared image of 2M1207 (blue) and its planet 2M1207b, as viewed by the Very Large Telescope. As of September 2006 this is the only confirmed extrasolar planet to have been directly imaged.

Extrasolar planets became a subject of scientific investigation in the mid-19th century. Astronomers generally supposed that some existed, but it was a mystery how common they were and how similar they were to the planets of the Solar System. The first confirmed detections were finally made in the 1990s; since 2002, more than twenty have been discovered every year. It is now estimated that at least 10% of sunlike stars have planets, and the true proportion may be much higher.[3] The discovery of extrasolar planets raises the question of whether some might support extraterrestrial life.[4]

Wednesday, December 06, 2006

Changing Mars Gullies Hint at Recent Flowing Water -

By Tariq Malik
Staff Writer
posted: 6 December 2006
1:00 p.m. ET

The changing appearance of gullies on Mars within the last few years has prompted new hopes that liquid water may have flowed recently on the red planet.

"The water thing clearly is a surprise to us," Michael Malin, who led a study that found the gully changes, told "The environment for Mars is not very conducive to water."

Malin and his colleagues used images from NASA's now silent Mars Global Surveyor (MGS) to revisit regions earlier this year where gullies, depression-like landforms on the red planet's surface, were found in 2000.

What they found were new, light-colored deposits that do not appear to have formed from martian landslides, but could be the work of frost, salt deposits or long-sought evidence that water flowed recently on Mars [images].

"Our level of certainty which we can address the question of whether the gully features that we're reporting on were formed by water is high, but not extremely high," said Malin, who has lightheartedly referred to the find as "the squirting gun."

"The evidence is mostly suggestive," he said.

Researchers have known of gullies on the Mars since 2000, when the MGS spacecraft's Mars Orbiter Camera (MOC)—built by Malin's Malin Space Science Systems in San Diego, California—first observed the eye-catching landforms. Found mostly on slopes or ridges, the gullies sparked long-running debates on whether they formed from groundwater seeping out of the martian surface or in dry landslides.

Malin's team also used the MOC instrument in their new study, which compared base images of two regions taken in 1999 and 2001 to more recent images captured in the years since.

In an area known as Terra Sirenum, new light-toned deposits coating gullies in April 2005 were not present in December 2001. Similar changes were seen in a crater etched into the Centauri Montes region of Mars, which apparently changed sometime between August 1999 and February 2004.

"Whether or not water was involved, it means that it is contemporary," Malin said of the findings, which will be detailed this week in the journal Science.

That liquid water once existed on Mars in some form has been known conclusively since 2004, when NASA's Opportunity rover found evidence that the wet stuff permeated rocks in the planet's ancient past.

Mars scientists have long associated the search for liquid water on red planet with the possibility of life, since the two are closely linked here on Earth. The existence of subsurface liquid water on Mars could also serve as a potential supply source for future red planet explorers.

But determining conclusively that the gully changes seen by MGS stem from liquid water is daunting, and will likely require an up-close visit—a challenge due to the risk of contaminating a gully site with Earth microbes or other material.

"Personally, I think you're going to have to go to one [and see]," Malin said, adding that the contaminate hurdle is daunting. "It's something that will not be trivially easy to go to, but something there's a lot of interest in."

Kenneth Edgett, a scientist at Malin Space Science Systems, told that the gully changes seen by MGS may be the first of many to be found by Mars-watching orbiters.

"More of these could happen if we just watch," Edgett said.

Pierre-Simon Laplace - Wikipedia

Born March 23, 1749
Beaumont-en-Auge, Normandy
Died March 5, 1827

Pierre-Simon, Marquis de Laplace (March 23, 1749, Beaumont-en-Auge, NormandyMarch 5, 1827, Paris) was a French mathematician and astronomer who put the final capstone on mathematical astronomy by summarizing and extending the work of his predecessors in his five volume Mécanique Céleste (Celestial Mechanics) (1799-1825). This masterpiece translated the geometrical study of mechanics used by Isaac Newton to one based on calculus, known as physical mechanics [1].

He is also the discoverer of Laplace's equation. Although the Laplace transform is named in honor of Laplace, who used the transform in his work on probability theory, the transform was discovered originally by Leonhard Euler, the prolific eighteenth-century Swiss mathematician. The Laplace transform appears in all branches of mathematical physics — a field he took a leading role in forming. The Laplacian differential operator, much relied-upon in applied mathematics, is likewise named after him.

He became count of the Empire in 1806 and was named a marquis in 1817 after the restoration of the Bourbons.


  • What we know is not much. What we do not know is immense.
  • I have no need of that hypothesis. ("Je n'ai pas besoin de cette hypothèse", as a reply to Napoleon, who had asked why he hadn't mentioned God in his book on astronomy)
  • "It is therefore obvious that..." (frequently used in the Celestial Mechanics when he had proved something and mislaid the proof, or found it clumsy. Notorious as a signal for something true, but hard to prove.)
  • The weight of evidence for an extraordinary claim must be proportioned to its strangeness. (known as the Principle of Laplace)

Tuesday, December 05, 2006

Moon Base Announced by NASA - National Geographic News

Moon Base Announced by NASA

December 4, 2006

NASA plans to construct a solar-powered outpost at one the moon's poles, officials with the U.S. space agency announced today.

The lunar base is expected to be permanently staffed by 2024.

The outpost concept was chosen over a competing strategy similar to the 1960s and '70s Apollo program—a series of brief trips to the moon.

The moon base will allow for sustained human presence on the moon's surface and help the agency prepare for future missions to Mars and beyond, explained NASA Deputy Administrator Shana Dale.

"It also enables global partnerships, allows for maturation of in situ resource utilization, and results in a path that is much quicker in terms of future exploration," Dale said at a press conference.

The announcement was part of NASA's congressionally mandated strategy to meet U.S. President George W. Bush's "Vision for U.S. Space Exploration," a plan outlined in 2004.

(Related: "NASA Budget Diverts Funds From Science to Spaceships" [February 8, 2006].)

The Bush plan includes returning humans to the moon no later than 2020. The goal is to take advantage of the moon's resources and to establish a launching point for further explorations.

(Photo gallery: "NASA's New Mission to the Moon.")

Dale added that the space agency is looking to international partners in the private and public sectors to participate in the construction and use of the moon base.

Polar Base

Once Dale and more than a thousand experts from 14 countries had decided to build a base, the obvious question was where.

"What we're looking at is polar locations—both the north pole and south pole," she said.

The moon's poles are believed to be bathed in near constant sunlight, which should allow for solar power generation.

In addition, polar temperatures are relatively moderate. Other lunar regions tend to fluctuate between extreme heat and cold.

Furthermore, the poles contain craters whose slopes may be permanently in the shadows—an indication that water ice and other potentially useful chemicals may be available.

"It's also interesting to note that we know very little about the poles on the moon. In fact, we know more about Mars," said Scott Horowitz, associate administrator for NASA's Exploration Systems Missions Directorate.

Doug Cooke, deputy associate administrator for the directorate, said one potential location is at the edge of Shackleton Crater. Located at the south pole, the crater is sunlit 75 to 80 percent of the time.

"And it is adjacent to a permanently dark region where there are potentially volatiles"—substances such as water ice, which would likely evaporate if exposed to much sunlight—"that we can extract and use," he said.

The potential site, he added, is about the size of the Washington Mall, which measures about 0.9 square mile (2.4 square kilometers).

Moon Lander

NASA envisions using an all-purpose lander that maximizes the amount of cargo that can be shipped to the moon in a single trip, Cooke said.

Horowitz likened the lander, which is in the preliminary design stages, to a pickup truck.

"You can put whatever you want in the bed. You take it to wherever you want, and so you can deliver cargo, crew [and] do it robotically [or] do it with humans onboard. These are the types of things we are looking for," he said.

"What you can put on the surface allows you to develop a capability much more quickly. The more you can land, the better it is."

The current plan envisions incremental base construction beginning in 2020 with four-person crews making seven-day visits to the moon until their basic necessities are in place.

"It will probably take several years—probably into the 2024 timeframe—before you see a fully functional base where you could have a continual presence with rotating crews like we have on the International Space Station today," Horowitz said.

Monday, December 04, 2006

Annan: Life for Iraqis worse than with Saddam - AP

Let's talk about the media coverage of the Iraq war.
There are probably thousands of things to say. Yet, one thing struck me. It's been years we are reading that "Iraq is one the verge of civil war". As "being on the verge of something" implies that it won't take long before the worse comes to the worse, one wonders wether there actually is a bit of of subtle war communication strategy involved.

How many civilians have died in Iraq for the past 12 months? Given that - daily - dozens are reported to die in sectarian attacks, we can safely assume that hundreds are killed daily all over the country (most deadly attacks being overshadowed by the biggest car bombing of the day).
Well, if 100,000 people die annually in a given country with a small population of less than 30 million inhabitants, is the media allowed to talk about "civil war"?
That's my question.


‘They had a dictator who was brutal but they had their streets,’ he says

Updated: 10:00 a.m. ET Dec. 4, 2006

LONDON - The level of violence in Iraq is "much worse" than that of Lebanon's civil war, outgoing U.N. Secretary General Kofi Annan said in an interview aired Monday.

Speaking to the British Broadcasting Corp., Annan agreed that the average Iraqi's life is worse now than it was under Saddam Hussein and called the situation in the country "extremely dangerous."

"Given the level of violence, the level of killing and bitterness and the way that forces are arranged against each other, a few years ago, when we had the strife in Lebanon and other places, we called that a civil war; this is much worse," Annan said.