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Genetic Exodus: DNA Tells ‘Global Story’ of Human Migration Out of Africa

Tom McFay — Tue, 23 Feb 2010 08:32:00 +0000

“Nearly all civilizations have their own origin or creation myth. Now we can use archaeogenetics to tell a global story that is robust and applicable to all human communities everywhere.” Colin Renfrew of the University of Cambridge, In recent years, DNA evidence has added important new tools for scientists studying the human past. “To understand what it is to be human, it is essential to understand the human past,” says Renfrew, who first coined the term “archaeogenetics” and is the author of a guest editorial in the special issue on Global Genetic History of Homo Sapiens in Cell (link below). The journey started around 60 to 70 thousand years ago in Africa, where modern humans evolved more than 150 thousand years ago, and where human diversity is still the highest among all continents in terms of genetic variation and languages. From there, humans settled Europe and South Asia and reached Oceania. The Americas (apart from the remote Oceanian islands) were settled last. Scientists who decoded the DNA of some southern Africans have found striking new evidence of the genetic diversity on that continent. They found, for example, that any two Bushmen in their study who spoke different languages were more different genetically than a European compared to an Asian. That was true even if the Bushmen lived within walking distance of each other. “If we really want to understand human diversity, we need to go to (southern) Africa and we need to study those people,” said Stephan Schuster of Pennsylvania State University. The genetic diversity of Africa’s population is no surprise to scientists. Modern humans evolved on that continent and have lived there longer than anyplace else. So that’s where they’ve had the most time to develop genetic differences. The varied environments of Africa have also encouraged genetic differences. Africa was the ancient source of modern humans worldwide, so “we’re looking really back into the wellspring of our genetic origins here,” said Richard Gibbs, a study author from the Baylor College of Medicine in Houston. The course and the extent of these first migrations remains evident in the genetic makeup of humans living today, but later migrations and the cultural practices that people carried with them—farming in particular—have also left their legacy. That legacy looks remarkably similar wherever farming spread, in Europe, Africa, and East Asia. A review by Mark Stoneking and Frederick Delfin at the Max Planck Institute for Evolutionary Anthropology in the Cell post below tells of an early migration of modern humans from Africa along a southern route to East Asia. Europe is perhaps the best-studied continent in terms of archaeogenetics, writes Martin Richards of the University of Leeds and his colleagues, and includes what Richards refers to as five major episodes, including the repopulation of Northern Europe after the Late Glacial Maximum. In the case of the Americas, DNA evidence has confirmed the Asian origin of indigenous Americans and more precise estimates of when Native Americans emerged. Dennis O’Rourke and Jennifer Raff of the University of Utah note, however, that many questions about the date of the initial colonization of the Americas remain. Overall, the reviews show just how clear it has become that all of us trace our evolutionary roots to Africa, Renfrew says. For most of history, humans were not evolving in isolation on separate continents. Using a genetic technique pioneered at Stanford, for example, a research team found that animal-herding methods arrived in southern Africa 2,000 years ago on a wave of human migration, rather than by movement of ideas between neighbors as previously believed. Prior research suggested that prehistoric people in eastern and southern Africa had little contact, with only two known migrations between the regions about 30,000 and 1,500 years ago. After Bantu-language speakers migrated from eastern to southern Africa 1,500 years ago, agriculture took off in southern Africa. But the timing of the Bantu migration didn’t quite match the 2,000-year-old anthropological evidence for the first sheep and cattle herds in southern Africa, so anthropologists were unsure whether the region’s agricultural knowledge came from a wave of ideas that spread in front of the migrating Bantu, or whether a separate migration brought the first herders. “There’s a tradition in archaeology of saying people don’t move very much; they just transfer ideas through space,” said Joanna Mountain, PhD, consulting assistant professor of anthropology. “We know that humans had to migrate at some point in their history, but we also know humans tend to stay put once they get someplace,” Underhill said. Instead of using archaeological evidence alone to guess whether people migrated, “all of a sudden, with genetics, you can actually address that question,” Mountain said. The researchers tracked genetic variation on the Y chromosome, the sex chromosome passed from father to son that encodes maleness, using a technique now widely used that was developed in the early 1990s by Underhill and colleagues in the lab of Luigi Cavalli-Sforza, professor emeritus of genetics. The method has given scientists a powerful window into ancient human migrations and prehistoric cultural shifts. The technique has also been adopted by some commercial genealogy services that offer Y-chromosome testing to the public. “Africa has the most genetic diversity in the world, but it is one of the least-studied places,” said Brenna Henn, a doctoral student in anthropology who was the study’s lead author. “I’ve always felt like there were a lot of stories there that nobody’s had the time or interest to look into.” The Stanford scientists picked the Y sex chromosome to examine for clues to migration because it changes very little from one generation to the next. Autosomes – the non-sex chromosomes – come in pairs, and the members of a pair can exchange bits of DNA during reproduction, making each autosome a mishmash of DNA from all of an individual’s ancestors. The Y chromosome, however, is a singleton; males inherit one Y chromosome and one X chromosome, while women have two X chromosomes. In men, only a tiny region of the Y chromosome can swap DNA with the X chromosome. This means almost all of the Y chromosome moves intact from father to son, changing only infrequently when a new mutation arises. That allows researchers to examine several generations of ancestry by looking at the Y chromosomes of living men. “The family tree of the Y chromosome is very, very clear,” Mountain said. The team analyzed Y chromosomes from men in 13 populations in Tanzania in eastern Africa and in the Namibia-Botswana-Angola border region of southern Africa. They discovered a novel mutation shared by some men in both locations, which implied those men had a common ancestor. Further analysis showed the novel mutation arose in eastern Africa about 10,000 years ago and was carried by migration to southern Africa about 2,000 years ago. The mutation was not found in Bantu-speakers, suggesting that a different group – Nilotic-language speakers – first brought herds of animals to southern Africa before the Bantu migration. This new genetic evidence correlates well with pottery, rock art and animal remains that suggest pastoralists – herders who migrated to new pasture with their flocks – first tended sheep and cattle in southern Africa around 2,000 years ago. The genetic finding also helps explain linguistic similarities between peoples in the two regions. “I like the fact that the linguistic, genetic and archaeological evidence all line up,” Henn said. “When you see lines of evidence converge on a single model, it means that’s probably something that actually happened.” “About a thousand years ago, a small group of anatomically modern humans migrated out of Africa,” writes Colin Renfrew. “We will never know for sure which causes initiated this migration… The process continued for thousands of years; today humans occupy the entire world.” Casey Kazan via Cell Sources: http://www.cell.com/current-biology/abstract/S0960-9822(09)02065-X http://www.google.com/hostednews/ap/article/ALeqM5iTaY6oZz8pr5kA8A9KrtqqJHkGOgD9DU4GM00

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Genetic Exodus: DNA Tells ‘Global Story’ of Human Migration Out of Africa

Did Population Density Trigger Exponential Growth of the Human Brain? (A Galaxy Classic)

Tom McFay — Tue, 23 Feb 2010 08:24:00 +0000

For the past 2 million years, the size of the human brain has tripled, growing much faster than other mammals. Examining the reasons for human brain expansion, University of Missouri researchers studied three common hypotheses for brain growth: climate change, ecological demands and social competition. The team found that social competition is the major cause of increased cranial capacity. To test the three hypotheses, MU researchers collected data from 153 hominid (humans and our ancestors) skulls from the past 2 million years. Examining the locations and global climate changes at the time the fossil was dated, the number of parasites in the region and estimated population density in the areas where the skulls were found, the researchers discovered that population density had the biggest effect on skull size and thus cranial capacity. “Our findings suggest brain size increases the most in areas with larger populations and this almost certainly increased the intensity of social competition,” said David Geary, Curator’s Professor and Thomas Jefferson Professor of Psychosocial Sciences in the MU College of Arts and Science. “When humans had to compete for necessities and social status, which allowed better access to these necessities, bigger brains provided an advantage.” The researchers also found some credibility to the climate-change hypothesis, which assumes that global climate change and migrations away from the equator resulted in humans becoming better at coping with climate change. But the importance of coping with climate was much smaller than the importance of coping with other people. “Brains are metabolically expensive, meaning they take lots of time and energy to develop and maintain, making it so important to understand why our brains continued to evolve faster than other animals,” said Drew Bailey, MU graduate student and co-author of the study. “Our research tells us that competition, whether healthy or not, sets the stage for brain evolution.” Posted by Jason McManus. Related Galaxy posts: 2050: What Will the Earth’s Population Be?

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Did Population Density Trigger Exponential Growth of the Human Brain? (A Galaxy Classic)

Most Ancient Stars in Observable Universe Unveiled -Hidden in Dwarf Galaxies

Tom McFay — Thu, 18 Feb 2010 09:20:00 +0000

New observations using ESO’s Very Large Telescope have been used to solve an important astrophysical puzzle concerning the oldest stars in our galactic neighborhood hidden until recently in dwarf galaxies orbiting the Milky Way. In comparison to the Milky Way, most dwarf galaxies are blob-like, 85% smaller (around 6700 vs 100,000 light-years across), containing around 30 billion stars. When the Universe was just a fraction of its current age, and galaxies such as the one we inhabit were nowhere to be seen, stars formed inside odd structures, that have long since disappeared. These structures are called dwarf irregulars, and the scientist believes that the peculiar type of stellar formation processes they display may resemble the original one and may provide clues as to how stars appeared shortly after the Big Bang. Unlike massive galaxies, such as the Milky Way, with highly-defined central regions, spiral arms and so on, dwarf irregulars are very small and diffuse groups of stars, which are the last thing to spring to mind when thinking of the word “galaxy”. Star formation in dwarfs today is similar to star formation right after the Big Bang. “We have, in effect, found a flaw in the forensic methods used until now,” says Else Starkenburg, lead author of the paper reporting the study. “Our improved approach allows us to uncover the primitive stars hidden among all the other, more common stars.” Primitive stars are thought to have formed from material forged shortly after the Big Bang, 13.7 billion years ago. They typically have less than one thousandth the amount of chemical elements heavier than hydrogen and helium found in the Sun and are called “extremely metal-poor stars.” They belong to one of the first generations of stars in the nearby Universe. Such stars are extremely rare and mainly observed in the Milky Way. Cosmologists think that larger galaxies like the Milky Way formed from the merger of smaller galaxies. Our Milky Way’s population of extremely metal-poor or “primitive” stars should already have been present in the dwarf galaxies from which it formed, and similar populations should be present in other dwarf galaxies. Metals” are all the elements other than hydrogen and helium. Such metals, except for a very few minor light chemical elements, have all been created by the various generations of stars. “So far, evidence for them has been scarce,” says co-author Giuseppina Battaglia. “Large surveys conducted in the last few years kept showing that the most ancient populations of stars in the Milky Way and dwarf galaxies did not match, which was not at all expected from cosmological models.” Element abundances are measured from spectra, which provide the chemical fingerprints of stars . Since the dwarf galaxies are typically 300 000 light years away — which is about three times the size of our Milky Way — only strong features in the spectrum could be measured, like a vague, smeared fingerprint. The team found that none of their large collection of spectral fingerprints actually seemed to belong to the class of stars they were after, the rare, extremely metal-poor stars found in the Milky Way. The team of astronomers around Starkenburg has now shed new light on the problem through careful comparison of spectra to computer-based models. They found that only subtle differences distinguish the chemical fingerprint of a normal metal-poor star from that of an extremely metal-poor star, explaining why previous methods did not succeed in making the identification. The astronomers also confirmed the almost pristine status of several extremely metal-poor stars thanks to much more detailed spectra obtained with the UVES instrument on ESO’s Very Large Telescope. “Compared to the vague fingerprints we had before, this would be as if we looked at the fingerprint through a microscope,” explains team member Vanessa Hill. “Unfortunately, just a small number of stars can be observed this way because it is very time consuming.” “Among the new extremely metal-poor stars discovered in these dwarf galaxies, three have a relative amount of heavy chemical elements between only 1/3000 and 1/10 000 of what is observed in our Sun, including the current record holder of the most primitive star found outside the Milky Way,” says team member Martin Tafelmeyer. “Not only has our work revealed some of the very interesting, first stars in these galaxies, but it also provides a new, powerful technique to uncover more such stars,” concludes Starkenburg. “From now on there is no place left to hide!” Casey Kazan via ESO

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Most Ancient Stars in Observable Universe Unveiled -Hidden in Dwarf Galaxies

Is the World’s Largest & Deepest Lake, 25-million-Years Old, Threatened? – A Galaxy Update

Tom McFay — Wed, 17 Feb 2010 09:30:00 +0000

As the oldest, largest and deepest lake on planet Earth, ancient Lake Baikal is known as the “grand dame” of all lakes. UNESCO declared it a World Heritage due to its stunning bio-diversity. Most of its 2500 some odd plant and animal species, including the freshwater seal, evolved in pristine isolation and are found nowhere else on the planet. In late January, Russian police raided the offices of the Baikal Environmental Wave group after it criticized a plan to reopen a paper mill next to Lake Baikal in Siberia that had been closed since 2008 due to pollution fears. Russian PM Vladimir Putin decreed that the mill could reopen. The Baikalsk Paper and Pulp Mill is the biggest employer in Baikalsk, a town of 17,000. The mill is owned by Russian billionaire Oleg Deripaska. Environmentalists have fought for years to keep the mill shut, arguing that it threatens the lake’s fragile ecosystem. The Siberian lake contains 20 percent of the entire world’s freshwater, and is large enough to hold all the water in the Great Lakes combined and then some. The lake has yielded many exciting aquatic wonders and likely holds many more undiscovered marvels in its incredibly deep waters. The 25 million year old lake predates the emergence of humans, but its splendor may not outlive us. Stephanie Hampton, the Deputy Director of the National Center for Ecological Analysis & Synthesis (NCEAS) who has been studying the lake shared with The Daily Galaxy what makes Baikal so exquisite. “Lake Baikal probably the most beautiful place I’ve ever been – I’m thinking especially right now of the day I spent on Olkhon Island when the wildflowers were spectacular and the serenity was awe-inspiring. It is the world’s most ancient lake with a proliferation of biodiversity that is breathtaking,” describes Hampton affectionately. “Where I would usually see 2 species of a particular type of crustacean (amphipods, in this case), instead, I see 344 species in all shapes and colors and sizes. Many of the unique fish in Baikal resemble deep-sea fishes rather than other freshwater fish that are more closely related to them – with big eyes and spindly bodies. Also, sponge forests are common. If you are surprised that I’m mentioning a sponge forest in a lake, it’s for a good reason: they are not that common in lakes!” Hampton notes with enthusiasm, “So here you are in this incredibly cold lake at fairly high latitude, and underwater, this sponge forest looks more like the Caribbean than the subarctic! It is really like a freshwater Galapagos in the midst of Siberia.” It doesn’t take much prodding to get information out of Hampton when it comes to the lake! Her abounding awe and reverence for one of Mother Nature’s most unique wonders is completely apparent. Unfortunately, according to Hampton and other experts, all this is about to change forever. Global warming has had a strong impact on the lake, and is threatening its incredibly unique life forms that evolved to live only in extreme cold. A multi-generational study involving careful and repeated sampling over six decades was recently reported in the journal Global Change Biology showing that the lake’s temperatures is rising dangerously fast. Hampton, who participated in the study, notes that the lake was expected to be among those most resistant to climate change, due to its tremendous volume and unique water circulation. But unfortunately, that does not appear to be the case. “So many organisms in and around Lake Baikal have evolved only in Lake Baikal, and they are very well-adapted to an extremely cold environment that is covered by ice for much of the year. More than half of the animals in Baikal are not found anywhere else! Lake Baikal has been around for 25 million years, so there has been plenty of time for organisms to evolve to its special environment – the warming associated with climate change is very abrupt, and it’s not clear whether or how these special organisms can adapt to a rapidly warming lake,” Hampton explains. Already there has been a rise in more common water organisms in the lake—a sight that does not bode well for the lakes original inhabitants. “We know that Siberia is one of the most rapidly warming regions of the world – the air temperature in Siberia has warmed at a rate that is about twice that of the average global rate of temperature increase. So when we approached this work with the Lake Baikal temperature data, we knew that the lake would have been exposed to a greater ambient temperature increase than lakes in other regions, but I certainly will admit to being surprised that the lake had warmed so rapidly since 1946. Why is it warming so much faster than the air? The answer probably involves ice,” Hampton explains. “Ice is a very prominent feature of life on Lake Baikal. Ice normally starts taking over the lake in January and it doesn’t leave until May or June – so, life goes on in Lake Baikal under ice for nearly half the year! The top predator in the lake, the Baikal seal, raises its pups on ice in the winter in snow caves, fishing for food in the lake water by using holes in the ice. Under the ice, algae (the microscopic plants at the base of the food web) that are found only in Lake Baikal, are well-adapted to achieve their greatest productivity while there is still thick, but clear, spring ice on the lake. So, both the top and the bottom of the food web in Baikal are very well adapted to long icy winters – this dependence on ice by the top and bottom of the food web is not common in lakes.” She continues, “We know from previous work, published by other researchers, that the ice is staying on the lake for a shorter time period now than it used to. When ice lasted longer in the past, it kept the lake insulated from air temperature changes for a longer portion of the year. Now that there is less ice, the water is warming faster. This is what other researchers also found on Lake Superior just last year. So, we can expect the lake to get warmer and warmer, as the ice lasts for a shorter time each year.” But what about the humans in the region? Even if the aquatic resident’s of Lake Baikal can’t thrive in the warmer weather, aren’t the nearby human settlements looking forward to a respite from the bitter cold that global warming may offer? Again, Hampton explains that the issue is a lot more complicated than most of us realize. “Some of the harshest winters of the century occurred within living memory for many Siberians, and it is easy to understand why Russians might welcome a longer growing season in Siberia. However, one big concern, as the air temperature increases, will be the deterioration of infrastructure as permafrost melts and the ground shifts under buildings and around pipes or other structures laid in the ground,” she explains, “Also, there are villages around Lake Baikal that can only be reached by water during the summer and by travel over the ice in winter – when ice is too thin for travel, but too thick for a boat, those villages are cut off from each other and from the main roads, so there will be societal impacts for some of these isolated villages where winter is already a pretty tough time of year.” In other words, climate change will likely have a negative impact on the human population as well. As far as the lake itself goes, Hampton points out that she’s not alone in her concern. “Russia, and many people are concerned for its welfare. A conservation organization called the Baikal Environmental Wave received a prestigious Goldman Environmental Prize this year, and there has been good community involvement in environmental issues surrounding the lake in recent years.” But awareness alone can’t save the grand dame’s biodiversity, nor other fragile habitats around the globe. It will take action too. But what can we ordinary people do to make any kind of real difference? Climate change expert Thomas Reichler, who was not involved in the study, told The Daily Galaxy that combating global warming starts with simple daily choices that everyone makes. You don’t have to change the world all by yourself, just change your own actions and let your example inspire other to do the same, he says. Things as simple as choosing to “drive smaller cars, drive less, and insulate your house well. Things like this can make a difference.” Posted by Rebecca Sato. If you liked this article, please give it a quick review on Digg , Reddit , or StumbleUpon .Thanks! Related Galaxy posts: The Crisis is Coming: How Peak Water Could Reshape Civilization The “Little Ice Age” Argument Makes a Comeback: Abrupt Climate Change Goes Both Ways, Warns Scientist Ancient Antarctic Lake Exploration Reports Warn that Climate Change & Eco-migration Could Lead to Increased Warfare Are Global Warming Models Accurately Predicting Our Future? New Study Reveals the Answer—A Galaxy Interview World’s Oldest Living Microbes May Cast Light on Aging & Life on Mars Ancient Antarctic Microbes Revived in Lab “Hunt for the Red October” Revives -Russia Challenges West Under Arctic Ice National Science Foundation Link: http://www.nsf.gov/news/news_summ.jsp?cntn_id=111511&org=olpa&from=news

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Is the World’s Largest & Deepest Lake, 25-million-Years Old, Threatened? – A Galaxy Update

The Once-Green Sahara Slowly Transformed into Planet’s Largest Desert (A Galaxy Classic)

Tom McFay — Sat, 13 Feb 2010 09:00:00 +0000

The world’s largest hot desert (seeing as technically Antarctica is the largest desert, though cold), the Sahara measures in at over 9 million square kilometers, and covers the majority of northern Africa. With an intermittent history that some believe may go back as far as 3 million years, recent research questions how it made its transition from lush greenery to hot sandy desert. According to the European-US-Canadian team of scientists behind the study, the Sahara finished a slow transition 2,700 years ago to become the desert that we know today. This is in direct contrast to previously held thoughts that the desertification of the Sahara came abruptly. Six thousand years ago we know that the massive northern area of Africa was very green; an area filled with trees, savannas and lakes. Sadly, most of the physical elements from that period of time though have been lost, and thus for a long time the exact tale of the Sahara’s geographic evolution has too been lost. However the scientists looked at layers of sediment in one of the largest remaining Saharan lakes, Yoa, located in Chad. This sediment managed to take them back through six millennia of climate history for the region. Their findings – upon conducting soil tests and reviewing biological indicators in the sediment – contradict previous modeling that showed a rapid collapse of vegetation in the region some 5,500 years ago. This according to Stefan Kropelin, a geologist at the Prehistoric Archaeology Institute of the University of Cologne who took part in the new study. Peter de Menocal of Columbia University published a study in 2000, where he reviewed sediments in the west of Mauritania, and found a sudden increase in wind-carried dust blown off the Sahara region, suggesting what he believed to be a swift climate change. However Kropelin believes that the data was misinterpreted. Posted by Josh Hill. Image credit: Jeff Malon. Source link: http://www.physorg.com/news129617309.html

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The Once-Green Sahara Slowly Transformed into Planet’s Largest Desert (A Galaxy Classic)

The Death Star? Not Quite. It’s the Massive Impact Scar on Saturn’s Moon, Mimas

Tom McFay — Sat, 13 Feb 2010 09:00:00 +0000

On Feb. 13, 2010, NASA’s Cassini spacecraft will be returning the highest-resolution images yet of Saturn’s battered moon Mimas. Mimas eye-ball-like crater is the scar of a violent, giant impact from the past – the 140-kilometer-wide (88-mile-wide) Herschel Crater. The diameter of the crater is about one-third that of the entire moon. The walls of the crater are about 5 kilometers (3 miles) high, and parts of the floor are approximately 10 kilometers (6 miles) deep. That’s DEEP! NASA scientists hope the encounter will help them explain why the moon was not blown to bits when the impact happened. They will also be trying to count smaller dings inside the basin of Herschel Crater so they can better estimate its age. . The Mimas flyby involves a significant amount of skill because the spacecraft will be passing through a dusty region to get there. Mission managers have planned for the Cassini spacecraft to lead with its high-gain antenna to provide a barrier of protection. At closest approach, the spacecraft will be flying about 9,500 kilometers (5,900 miles) above the moon. Cassini will start taking images and measurements shortly after closest approach. . Casey Kazan via JPL/NASA Image Credit: During its approach to Mimas on Aug. 2, 2005, the Cassini spacecraft narrow-angle camera obtained multi-spectral views of the moon from a range of 228,000 kilometers (142,500 miles). NASA/JPL/Space Science Institute.

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The Death Star? Not Quite. It’s the Massive Impact Scar on Saturn’s Moon, Mimas

Is Jupiter Undergoing Massive Climate Change? A Weekend Feature

Tom McFay — Sat, 13 Feb 2010 08:50:00 +0000

The Hubble Space Telescope and Keck Observatory images may support the idea that Jupiter is in the midst of violent global climate change. This theory was first proposed in 2004 by Phil Marcus, a professor of mechanical engineering at the University of California, Berkeley. The planet’s temperatures may be changing by 15 to 20 degrees Fahrenheit, with the giant planet getting warmer near the equator and cooler near the South Pole. Marcus predicted that large changes would start in the southern hemisphere around 2006, causing the jet streams to become unstable and spawn new vortices as has been proven out by the emergence of new swirling red storms. Jupiter’s atmosphere has a zig-zag pattern of twelve jet streams which make up its signature pastel-toned bands. Earth, by comparison, has only two jet streams. The Great Red Spot is sandwiched between two of these jets streams, forcing the winds that power those perimeter winds to deflect around the spot. Spacecraft observations of the way bands of high winds scream past the Red Spot show how the spot — inaccurately described as a storm — is actually far calmer at its center than other parts of the Jovian atmosphere. The winds at the center are just 9 or 10 miles per hour, whereas around the perimeter they exceed 200 miles per hour. A new, third red spot, which is a fraction of the size of the two other red spots, has been observed on Jupiter to the west of the Great Red Spot in the same latitude band of clouds. The visible-light images were taken on May 9 and 10 with Hubble’s Wide Field and Planetary Camera. The new red spot morphed from a white oval-shaped storm to a red color indicating its swirling storm clouds are rising to heights like the clouds of the Great Red Spot. Astronomers surmise that one possible explanation is that the red storm is so powerful it dredges material from deep beneath Jupiter’s cloud tops and lifts it to higher altitudes where solar ultraviolet radiation — via some unknown chemical reaction — produces the familiar brick color. Because all three oval storms are bright in near-infrared light, they must be towering above the methane in Jupiter’s atmosphere, which absorbs the Sun’s infrared light and so looks dark in infrared images. Turbulence and storms first observed on Jupiter more than two years ago are still raging, as revealed in the latest pictures. The Hubble and Keck images also reveal the change from a rather bland, quiescent band surrounding the Great Red Spot just over a year ago to one of incredible turbulence on both sides of the spot. The Great Red Spot has persisted for as long as 200 to 350 years, based on early telescopic observations. If the new red spot and the Great Red Spot continue on their courses, they will encounter each other in August, and the small oval will either be absorbed or repelled from the Great Red Spot. Red Spot Jr. which lies between the two other spots, and is at a lower latitude, will pass the Great Red Spot in June. Posted by Casey Kazan. Image: Jupiter and Giant Red Spot seen from its moon, Io. Vistapro Landscape Imagery Rendered by Jeff Bryant. Related Galaxy posts: Monitoring Climate Change -Experts Say We Need Lunar Observatories Climate Change on & Venus -A Lesson for the Blue Planet? Jupiter’s Europa- Will It Provide the 1st Proof of Extraterrestrial Life? Source link: http://www.labspaces.com/view_news_comments.php?newsID=6042

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Is Jupiter Undergoing Massive Climate Change? A Weekend Feature

The Haiti Response: Is the Human Species Hardwired to be Compassionate? (A Weekend Feature)

Tom McFay — Sat, 23 Jan 2010 13:49:08 +0000

The world’s incredible outpouring of help to thhe people of Haiti raises the queestion: are we evolving to become more compassionate and collaborative in our quest to survive and thrive? A research team at the University of California, Berkeley, says “yes.” They are challenging long-held beliefs that human beings are wired to be selfish. In a wide range of studies, social scientists are amassing a growing body of evidence to show we are evolving to become more compassionate and collaborative in our quest to survive and thrive.The researchers have found compelling evidence that people who are more empathetic possess a particular variation of the oxytocin receptor gene. The findings support other research showing that oxytocin plays a major role in countering stress. Previous studies have also linked this genetic variation with autism and parenting styles, says study coauthor Sarina Rodrigues, assistant professor of psychology at Oregon State University. All humans inherit a variation of this gene or “allele” from each parent. The study looked at the three combinations of gene variations of the oxytocin receptor. The most empathetic—able to get an accurate read on others’ emotions—had two copies of the “G allele.” In contrast, members of the AA and AG allele groups were found to be less capable of putting themselves in the shoes of others and more likely to get stressed out in difficult situations. “This is the first study to suggest that a tendency to be more empathetic and stress reactive than others may be influenced by a single gene,” notes Rodrigues. Informally known as the “cuddle” or “love” hormone, oxytocin is secreted into the bloodstream and the brain, where it promotes social interaction, bonding and romantic love, among other functions. It is also key to procreation, activating uterine contractions during childbirth and lactation for breastfeeding. But while nature might have given some of us the DNA to be more empathetic, those who are not in the GG group should not despair, Rodrigues says. “There are plenty of people in the AA or AG gene pool who are empathetic, caring individuals,” adds Rodrigues, who is not a double G but counts herself as caring and empathetic. In the study of some 200 young men and women of diverse ethnicities, participants, who provided DNA samples, filled out questionnaires that gauged their levels of empathy and their ability to read emotions displayed in eye expressions. Those with the GG variation were better at reading eye expressions than their AA and AG counterparts. Participants were also were given stress reactivity tests, including one that measured their heart rate as they awaited loud blasts of noise. While female participants were found overall to be more sensitive to stress, both men and women in the GG group maintained a lower heart rate in the face of the sound blasts.. “Not everyone is going to be a touchy-feely person,” Rodrigues adds. “We should reach out to people who aren’t because research shows it’s better for everyone to be socially connected.” The study was funded by the Metanexus Institute and UC Berkeley’s Greater Good Science Center. Jason McManus from UC Berkeley news

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The Haiti Response: Is the Human Species Hardwired to be Compassionate? (A Weekend Feature)

Are Big Brains Predictors of Success?

Tom McFay — Thu, 21 Jan 2010 08:30:00 +0000

A new study conducted at the University of Illinois has found that nearly a quarter of the variability in achievement seen among men and women trained on a new video game could be predicted by measuring the volume of three structures in their brains. Participants were trained on one of two versions of Space Fortress, a video game that requires players to try to destroy a fortress without losing their own ship to one of several potential hazards. “This is the first time that we’ve been able to take a real world task like a video game and show that the size of specific brain regions is predictive of performance and learning rates on this video game,” said Kirk Erickson, a professor of psychology at the University of Pittsburgh and first author on the study. The study adds to the evidence that specific parts of the striatum, a collection of distinctive tissues tucked deep inside the cerebral cortex, profoundly influence a person’s ability to refine his or her motor skills, learn new procedures, develop useful strategies and adapt to a quickly changing environment. Research has shown that expert video gamers outperform novices on many basic measures of attention and perception, but other studies have found that training novices on video games for 20 or more hours often yields no measurable cognitive benefits. These contradictory findings suggest that pre-existing individual differences in the brain might predict variability in learning rates, the authors wrote. The cutaway image above shows four brain structures studied in the video-game research: the caudate nucleus (blue) and putamen (red) involved in motor learning, but research has shown they are also important to the cognitive flexibility that allows one to quickly shift between tasks. The nucleus accumbens (orange spot) and hippocampus (green). The nucleus accumbens (ah-COME-bins) is known to process emotions associated with reward or punishment. Researchers found linkages between game performance and the first three structures, but no linkage involving the hippocampus. The researchers began with a basic question about these structures, said Arthur Kramer, a professor of psychology at the Beckman Institute for Advanced Science and Technology at the University of Illinois: “Is bigger better?” They used high-resolution Magnetic Resonance Imaging (MRI) to analyze the size of these brain regions in 39 healthy adults (aged 18-28; 10 of them male) who had spent less than three hours a week playing video games in the previous two years. The volume of each brain structure was compared to that of the brain as a whole. Half of the study participants were asked to focus on maximizing their overall score in the game while also paying attention to the various components of the game. The other participants had to periodically shift priorities, improving their skills in one area for a period of time while also maximizing their success at the other tasks. The latter approach, called “variable priority training” encourages the kind of flexibility in decision-making that is commonly required in daily life, Kramer said. Studies have shown that variable priority training is more likely than other training methods to improve those skills people use every day. The researchers found that players who had a larger nucleus accumbens did better than their counterparts in the early stages of the training period, regardless of their training group. This makes sense, Erickson said, because the nucleus accumbens is part of the brain’s reward center, and a person’s motivation for excelling at a video game includes the pleasure that results from achieving a specific goal. This sense of achievement and the emotional reward that accompanies it is likely highest in the earliest stages of learning, he said. Players with a larger caudate nucleus and putamen did best on the variable priority training. “The putamen and the caudate have been implicated in learning procedures, learning new skills, and those nuclei predicted learning throughout the 20-hour period,” Kramer said. The players in which those structures were largest “learned more quickly and learned more over the training period,” he said. “This study tells us a lot about how the brain works when it is trying to learn a complex task,” Erickson said. “We can use information about the brain to predict who is going to learn certain tasks at a more rapid rate.” Such information might be useful in education, where longer training periods may be required for some students, or in treating disability or dementia, where information about the brain regions affected by injury or disease could lead to a better understanding of the skills that might also need attention, he said. Casey Kazan via materials provided by University of Illinois at Urbana-Champaign

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Are Big Brains Predictors of Success?

Image of the Day: Zooming in on the Cat’s Paw Nebula (VIDEO)

Tom McFay — Thu, 21 Jan 2010 08:18:00 +0000

Few objects in the sky have been as well named as the Cat’s Paw Nebula, a glowing gas cloud resembling the gigantic pawprint of a celestial cat out on an errand across the Universe. British astronomer John Herschel first recorded NGC 6334 in 1837 during his stay in South Africa. Despite using one of the largest telescopes in the world at the time, Herschel seems to have only noted the brightest part of the cloud, seen here towards the lower left. NGC 6334 lies about 5500 light-years away in the direction of the constellation Scorpius (the Scorpion) and covers an area on the sky slightly larger than the full Moon. The whole gas cloud is about 50 light-years across. The nebula appears red because its blue and green light are scattered and absorbed more efficiently by material between the nebula and Earth. The red light comes predominantly from hydrogen gas glowing under the intense glare of hot young stars. NGC 6334 is one of the most active nurseries of massive stars in our galaxy and has been extensively studied by astronomers. The nebula conceals freshly minted brilliant blue stars — each nearly ten times the mass of our Sun and born in the last few million years. The region is also home to many baby stars that are buried deep in the dust, making them difficult to study. In total, the Cat’s Paw Nebula could contain several tens of thousands of stars. Particularly striking is the red, intricate bubble in the lower right part of the image. This is most likely either a star expelling large amount of matter at high speed as it nears the end of its life or the remnant of a star that already has exploded. This new portrait of the Cat’s Paw Nebula was created from images taken with the Wide Field Imager (WFI) instrument at the 2.2-metre MPG/ESO telescope at the La Silla Observatory in Chile, combining images taken through blue, green and red filters, as well as a special filter designed to let through the light of glowing hydrogen. VIDEO ZOOM Casey Kazan via ESO