"In the Arctic, evidence from satellite data, submarine data, and oceanographic field observations reveal the diminished areal extent, shorter seasonal duration, and extensive thinning of sea ice," the letter said. "Summer sea ice cover in the Arctic has already been reduced in areal extent by 10-20 percent over the last 30 years."

The Arctic region is especially sensitive to global warming because of the reflectivity of ice and cloud cover, the scientists said. Despite slight cooling in some pockets of the Artic, overall the region has experienced substantial warming. Records show that average annual temperatures are 3.5 to 5 degrees Fahrenheit warmer in Alaska and Siberia. Siberian winters and temperatures in the western Canadian Arctic, meanwhile, are 7 degrees warmer than before, the letter said.

The scientists also cited the 2001 Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Pierrehumbert served as lead author of this report, which involved the participation of more than 2,000 scientists from 100 countries. "The IPCC report concluded that the observed global climate changes cannot be accounted for by natural climate forcings alone;" said the scientists in their letter.

Additional research conducted since 2001 has strengthened the IPCC's findings, according to Martin and her colleagues. "In 2005, the Arctic Council, an intergovernmental forum with members from eight nations, including the United States, referenced the findings of the IPCC Third Assessment Report in their Arctic Climate Assessment and added that 'there is new and strong evidence that in the Arctic much of the observed warming over this period [the last 50 years] is also due to human activities."

Taking into account increasing temperatures and atmospheric carbon dioxide, along with fundamental climate theory, the scientists observe that global surface temperature is currently unstable, or, in scientific terms, "not in a steady state," nor will it be for years to come. The planet is, as a result, committed to a continued trend in global warming for centuries to come, according to the scientists.

"Immediate reductions of greenhouse gas emissions well beyond those that may be considered by some measures 'sustainable' emissions rates are therefore imperative. We urge the Fish and Wildlife Service to acknowledge the threat of Arctic warming on the Polar Bear."

University of Chicago - http://www-news.uchicago.edu

Reconstruction of the Early Cretaceous (~110-115 million year old) amphibious bird Gansus yumenensis. Despite its antiquity, Gansus is remarkably closely related to modern birds - the most advanced Early Cretaceous bird yet discovered. (Mark A. Klingler/ CMNH)

The famous proto-bird Archaeopteryx. (Image copyright Joe Tucciarone and Jeff Poling)

"Webbed feet is an adaptation that has evolved repeatedly in widely separate groups of animals, such as sea turtles, whales and manatees, and would only hinder climbing or landing in trees," Harris said. "The big bony crest that sticks off the knee-end of their lower leg bones are similar to structures seen in loons and grebes. These crests anchor powerful muscles needed for diving under water and swimming."

According to Harris, these adaptations all demonstrate how the Gansus branch of the family tree, the structurally modern birds called ornithuromorphs, split from the enantiornitheans (or "opposite birds"). Enantiornitheans were among the feathered fossils found in northeastern China during the 1990s.

"The enantiornitheans had the best adaptations for perching, so they were able to dominate the ecological niche that we would associate with songbirds, cuckoos, woodpeckers or birds of prey," Harris said. "Gansus appears to have had adaptations for a lifestyle centered around water, based on things like the proportions of the leg and foot bones."

While the enantiornitheans are now long gone, their perching lifestyle has now been taken over by the descendents of birds like Gansus. What remains a mystery for now, according to the researchers, is how the amphibious lifestyle of birds like Gansus helped enable them to survive the cataclysmic end of the dinosaurs 65 million years ago.

University of Pennsylvania - http://www.upenn.edu/pennnews

In a study conducted by Udo Groeger and Lutz Wiegrebe from the Ludwig-Maximilians-Universitaet in Munich, Germany, two vampire bats were taught to associate recordings of different humans breathing with different cattle blood dispensers, providing food rewards. They were then played short clips of people breathing and had to associate them with the correct individual by going to the correct dispenser.

Four human participants were asked to associate the same short clips with the correct individual.

The vampire bats were able to spontaneously associate the clips with the particular individuals, regardless of whether the individual was recorded breathing at rest or breathing while under physical strain. The human participants were also able to recognise some clips, but they were unable to recognise the clips of breathing recorded under physical strain.

BioMed Central - http://www.biomedcentral.com

The planet Neptune (NASA)

In this schematic of the outer solar system, "Trojan" asteroids can be seen sharing the orbits of Jupiter and Neptune. At either of two points 60 degrees away from each planet, the gravitational forces of the planet and the Sun combine to lock the asteroids into a stable, synchronized orbit. Three new Trojans have been found in the region ahead of Neptune, bringing the total to four; the discovery suggests that Neptune hosts clouds of Trojans that are more dense and populous than those in Jupiter's orbit. (Image: Scott Sheppard)

In 2004, Sheppard and Chadwick Trujillo of the Gemini Observatory, who is also an author on the current study, found the second Neptune Trojan using Carnegie's Magellan-Baade 6.5 meter telescope in Las Campanas, Chile. They found two more in 2005, bringing the total to four, and observed them again using the 8.2 meter Gemini Telescope in Hawaii in order to accurately determine their orbits. All four of the known Neptune Trojans reside in the planet's leading Lagrangian point.

One of the new Trojans has an orbit that is more steeply tilted to the plane of the solar system than the other three. Although only this one has such a steep orbit, the methods used to observe the asteroids are not sensitive to objects so far out of tilt with the rest of the solar system.

The very existence of this Trojan suggests that there are many more like it, and that Neptune's Trojans as a whole occupy thick clouds with complex, interlaced orbits.

"We were really surprised to find a Neptune Trojan with such a large orbital inclination," Trujillo said. "The discovery of the one tilted Neptune Trojan implies that there may be many more far from the solar system plane than near the plane, and that the Trojans are really a "cloud" or "swarm" of objects co-orbiting with Neptune."

A large population of high-inclination Neptune Trojans would rule out the possibility that they are left over from early in the solar system's history, since unaltered primordial asteroid groups should be closely aligned with the plane of the solar system.

These clouds probably formed much like Jupiter's Trojan clouds did: once the giant planets settled into their paths around the Sun, any asteroid that happened to be in the Trojan region "froze" into its orbit.

Sheppard and Trujillo also compared, for the first time, the colors of all four known Neptune Trojans. They are all about the same shade of pale red, suggesting that they share a similar origin and history. Though it is hard to tell for sure with only four on the books, the researchers believe that the Neptune Trojans might share a common origin with the Jupiter Trojans and outer irregular satellites of the giant planets.

These objects might be the last remnants of the countless small bodies that formed in the giant planet region, most of which eventually became part of the planets or were tossed out of the solar system.

Carnegie Institution - http://www.carnegieinstitution.org

A brain map illustrates different levels of activity as brain circuits process erotic and neutral visual materials 185 milliseconds after a picture is viewed. Red zones represent the highest activity levels in the brain regions processing erotic pictures. (WUSTL)

The ERPs begin firing in the brain's cortex long before a person is conscious of whether they are seeing a picture that is pleasant, unpleasant or neutral.

Erotic is in the eye of the beholder: does this turn you on?

But when the picture is erotic, ERPs begin firing within 160 milliseconds, about 20 percent faster than occurred with any of the other pictures. Soon after, the ERPs begin to diverge, with processing taking place in different brain structures for erotic pictures than those that process the other images.

"When we present a stimulus to a subject — for example, when a picture appears on a screen — it changes ongoing brain activity in certain ways, and we can detect those changes," Anokhin says.

Pictures appeared on a screen at 12 to 18 second intervals, and each picture remained on the screen for about 6 seconds. The subjects were instructed to do nothing other than look at the pictures.

How about this?

A great deal of past research has suggested that men are more visual creatures than women and get more aroused by erotic images than women. Anokhin says the fact that the women's brains in this study exhibited such a quick response to erotic pictures suggests that, perhaps for evolutionary reasons, our brains are programmed to preferentially respond to erotic material.

"Usually men subjectively rate erotic material much higher than women," he says. "So based on those data we would expect lower responses in women, but that was not the case. Women have responses as strong as those seen in men."

Because the electroencephalogram (EEG) technology cannot pinpoint specific brain structures involved in this visual processing, Anokhin says it's not clear exactly which circuits are reacting to these visual scenes. Recent studies in primates recorded the electrical activity of single neural cells within the brain and have shown that the frontal cortex contains neurons that can discriminate between different categories of visual objects such as dogs versus cats.

Betty Page, maybe?

Whether or not the human prefrontal cortex contains special neurons that are "tuned" for sex remains a subject for future studies.

"The newer and more advanced technologies such as MRI and PET provide much better spatial resolution," he says. "Those methods can better localize areas of brain activity, but ERPs have a much better temporal resolution. The EEG can record neuronal activity in real time. When measuring activity in milliseconds, any delay is undesirable."

Most of Anokhin's research is centered on the genetic and neurobiological bases of behavioral traits that might be associated with increased vulnerability to alcoholism and addictive disorders. He believes this study could contribute to that work by detecting differences between responses to images with different emotional significance.

Because many psychiatric disorders also are associated with poor processing of signals associated with reward and pleasure, as well as sexual disturbances, he believes the way the brain processes emotional pictures, including erotic materials, might help scientists better understand some forms of mental illness.

Washington University School of Medicine - http://medinfo.wustl.edu

The actual interface with which Carmen Vidaurre has worked with is based on electroencephalograms (EEG) of the individual, although there are others that use signals recorded from electrodes fitted directly into the brain.

The user and the interface are highly interdependent “systems” that, up to recently, adapted to each other independently. In the past, when a non-experienced individual started to use a BCI, the systems were unable to supply feedback, i.e. the individual was unable to see the results of their brain patterns on the screen.

The majority of the population are capable of learning to control an adaptive BCI

With those outdated systems and, after a number of prior, data-collecting sessions, feedback was included and, in this way, the subjects started to adapt themselves to the computer, using the interface response to the patterns extracted from the signals. However, few users could use these interfaces because the patterns generated during the trial sessions had to be greatly similar to those sessions with feedback.

One of the biggest problems found by other users and researchers into these “static” systems was that the patterns extracted from the signals recorded in the trial sessions were quite different from those signals recorded in the presence of feedback. For example, the visual input was different between both types of sessions and this difference significantly changes brain activity in specific areas thereof.

For inexpert users it is very difficult to adapt to the traditional interface because they are unable to generate stationary patterns in time, probably due to their inexperience. They find it very complicated to reproduce mental states sufficiently similar to be correctly classified.

Pioneering research

This is why, this PhD has designed, in a pioneering way, two in-line adaptive classifications, within a completely adaptive interface and capable of supplying feedback to inexpert individuals in the first stages of its use. With this system, the interface and the individual adjust to each other, one learning from the other in a reciprocal manner. In this way it has been possible to eliminate the initial trial sessions without feedback, thus diminishing the total skills acquisition time and the individuals are able to find an operating strategy directly with feedback.

Moreover, the experiments carried out with individuals without prior experience, have demonstrated that the majority of the population are capable of learning to control an adaptive BCI. Specifically, in the trials undertaken with 30 persons in Austria and Pamplona, it was found that 20 had been able to control the interface “very well” within 4 hours.

No mouse - but probably a silly hat

Four modules

The interface is basically made up of four modules that take charge of, respectively, the acquisition and pre-processing of the signal; the extraction of its characteristics; the classification of the signal in the various patterns the interface possesses and, finally, the feedback, the stage in which it is tested whether the action has been the expected one or not.

This research has mainly focused on the classification module, dealing with identifying the type of signal that the subject is sending. In an interface that has, for example, two patterns (imagination of the movement of the left hand and of the movement of the right hand), the classification module tries to decide to which pattern the current signal belongs.

Universidad Pública de Navarra - www.unavarra.es