Advances in studying genes mean that scientists in evolutionary developmental biology or "evo-devo" can now explain more clearly than ever before how bats got wings, the turtle got its shell and blind cave fish lost their eyes, says University of Massachusetts Amherst evolutionary biologist Craig Albertson.
He recently won a five-year, $625,000 Faculty Early Career Development grant from the National Science Foundation (NSF) to study the evo-devo of jaws in cichlid fish, tropical freshwater relatives of the tilapia. These highly adaptable cousins of sunfish, usually medium-sized and looking a bit like perch, have a phenomenal ability to undergo evolutionary change. They've developed 1,000 new species in Lake Malawi, Africa, over the past million years, a far faster pace than usual for other vertebrates in a similar period.
The NSF grant is the foundation's most prestigious award in support of junior faculty who exemplify the role of teacher-scholars through outstanding research, excellent education and the integration of both.
Through evo-devo studies, scientists now know that much biodiversity is due not only to differences in genes, but to changes in how and when genes are expressed, says Albertson. They also now recognize that genes interact with each other and the environment in development to determine phenotype, or an animal's observable traits.
"This carries Charles Darwin's ideas forward to a new level, to previously unconsidered sources of variation that can affect the evolution of traits. One in particular is phenotypic plasticity, the idea that different patterns of variation will be produced in different environments," Albertson says.
He chose to study evo-devo in cichlid fish because "they're obviously doing something right, from an evolutionary perspective, in a very dynamic environment, Africa's Rift Valley." Lake Malawi water levels have fluctuated up to 300 meters in the past 2 million years, providing everything from clear fresh water to an oxygen-poor soup high in salt, alkali or sediment, for example, but cichlids continue to adapt and survive.
Jaws are a good marker of adaptation because they are linked to survival, and the jaws of Lake Malawi cichlids can change rapidly to take advantage of new food resources. For example, open-water feeders have long jaws to snatch free-swimming, mobile prey, while bottom-feeders tend to have short, stout jaws for scraping algae from rocks. It is clear that these differences in jaw type are genetically determined, but Albertson wants to find out how much is also determined by the environment.
In studies he started at Syracuse University before coming to UMass Amherst in 2011, Albertson and colleagues are working to identify the set of genes responsible for determining jaw shape in both "normal" and "extreme" environments. They are taking a genetic mapping approach, using hybrids from a cross between two species differing subtly in jaw length. To begin, they raised an initial group of hybrids on an algae-based flake food, which is very easy for the fish to eat, Albertson explains. This population will be used to map genetic determinants of jaw shape under "normal" conditions.
Next, the biologists split the resulting hybrid families and reared them on two different diets, an algae-based diet spread on lava rocks, requiring fish to scrape to feed. These fish developed shorter jaws to accomplish this. The other treatment involved the same food, this time ground and sprinkled on the water surface. These fish had to suck food out of the water column; they developed longer jaws as they became more efficient at this task.
As Albertson explains, "The idea is that these two conditions should be similar to those in early Lake Malawi, when fish first arrived from surrounding rivers. Presumably the ancestors of Lake Malawi cichlids all looked the same, but some went up to suction feed while others went down to scrape, and plasticity produced fish with different jaw lengths. By re-creating this scenario and mapping the genes that underlie these environmentally induced shape differences, we hope to learn about the genetic interactions that were the first step in producing the 1,000-plus species in the lake today."
One key question he and his colleagues want to answer is whether the same set of genes are involved in developing crushing jaws and sucking jaws under normal and extreme environments. "We don't know if patterns of plasticity will affect patterns of evolution. We may see a different genetic response to distinct mechanical stimuli. But if we do recover a common set of genes under both normal and extreme conditions, it would substantiate key theories with respect to plasticity's role in evolutionary change."
Read more at Science Daily
Feb 11, 2012
Estrogen Turns Male Snakes into Same-Sex Charmers
The finding, published in the Journal of Experimental Biology, has implications for understanding the environmental impact of compounds that mimic the effect of estrogen, found in some chemicals and pesticides.
Estrogen, the researchers found, is key to a female's release of pheromones and thus, reproduction.
Here's how it works: For the red-sided garter snake, picking up a mate takes but a second and a flick of the tongue. When a male detects a possible mate nearby, he licks the female with a quick flick of his tongue. The chemical cues, called pheromones, exuded by the females are so strong it takes but an instant, the researchers say, for the male to determine the other snake's species, sex, population, reproduction condition, size and age. In fact, the males are totally dependent on these pheromones for snake reproduction.
Every spring, tens of thousands of these garter snakes emerge from their limestone caves north of Manitoba, Canada, for mating. Intense competition ensues, as males swarm (and tongue) female snakes in an effort to be the first to mate with her. The frenzy appears as twisting balls of snakes called mating balls.
The males tend to choose the larger, more mature gals, because these females can produce more babies; they also have a slightly different chemical signature in their pheromones. While young, small females do get action, they aren't the preferred mates.
Once they mate, the females emit a different pheromone, confirming "no more sex," causing other males to lose interest and leave the area.
In the new study, the researchers implanted male garter snakes in their natural environment, each with a capsule that raised their estrogen levels to approximately match those of female snakes. After one year of these estrogen supplements, the male snakes started secreting a pheromone that seemed to cause other males to swarm to them, forming clumps of writhing snakes tangled together. Apparently, the estrogen caused the males to secrete "female" pheromones.
"We thought this might work, but we were surprised the results were so compelling," study researcher Robert Mason, a professor of zoology at Oregon State University, said in a statement. "The amount of estrogen the male snakes received was nothing unusual, just about what a normal female would produce."
Read more at Discovery News
Feb 10, 2012
Ocean Warming Causes Elephant Seals to Dive Deeper
The southern elephant seals from Marion Island, located in the south western part of the Indian Ocean, are extreme divers in the truest sense of the word. The animals spend more than 65 per cent of their lives in depths of over 100 metres, diving far deeper than their fellow species in southern areas. The maximum dive depth of these seals is over 2000 metres. However, the water masses through which the elephant seals from Marion Island swim in search of food are becoming increasingly warmer due to climate change and are forcing the animals to dive deeper. The Southern Ocean is warmed primarily in the water levels up to a depth of 1000 metres and therefore in those areas in which squid and fish ought to be found. "This prey is moving down to greater depths presumably due to the increasing water temperatures and this is forcing the seals to follow them," explains Dr. Horst Bornemann from the Alfred Wegener Institute.
Over the course of several years he and his colleague Dr. Joachim Plötz together with Dr. Trevor McIntyre and other seal researchers from the Mammal Research Institute (MRI) in South Africa have fitted over 30 elephant seals with satellite transmitters. These transmitters, the size of a fist, are attached to the head of the seals using artificial resin immediately after moulting and measure the dive depth, water temperature and salinity every time the animals dive. When the animal resurfaces to breathe the transmitters send their data to the respective research institutes via satellite. The results show that the elephant seals need to dive deeper in warmer water so that they ultimately have less time to actually search for food. "We therefore assume that the animals will find less prey in warmer water masses," explains Joachim Plötz.
The scientists from Bremerhaven will be going back to Marion Island in April of this year to collect evidence for their theory. This time they wish to equip the animals with a "jaw movement" sensor which has been developed by Japanese biologists at the National Institute of Polar Research in Tokyo. It is not much larger than a small finger and notices when the seal opens its mouth. "So far we can only derive from the dive profile whether an elephant seal was probably following a fish swarm. With this new measuring device we learn whether he has actually eaten," says Joachim Plötz.
Using this forage data the AWI biologists wish to draw conclusions as to the spatial and temporal distribution of particularly productive zones in the South Polar Sea. "The food in the sea is unevenly distributed. It is not worth the seals fishing anywhere and at any time. With the new data we hope to see the routes taken by the elephant seals of Marion Island and the water levels in which they find food," says Horst Bornemann.
The scientists also take days of walking over the "island of horizontal rain" into the bargain to achieve their research goal. "The elephant seals of Marion Island are very loyal to their location. They return to this island time and again to moult and mate. This behaviour gives us the opportunity to consistently fit measuring devices to the same animals thereby gaining an insight into the movement patterns of individual animals. Their movement and dive routes help us to find out where the oceanic food grounds of the Marion Island elephant seals are located," explains Joachim Plötz.
Read more at Science Daily
Kids Show Cultural Gender Bias
Talk about gender confusion! A recent study by University of Alberta researchers Elena Nicoladis and Cassandra Foursha-Stevenson in the Journal of Cross-Cultural Psychology into whether speaking French influenced how children assigned gender to objects yielded some interesting observations. Nicoladis and Foursha-Stevenson found some differences between the unilingual English children and the bilingual French-English children they surveyed.
Some of the more startling results from the Anglo crowd? Cows are boys. Cats and stars are girls.
Le culture or la culture: our bias
The researchers showed objects or images to the children participating in the study and asked them whether the objects seemed to be masculine or feminine in nature. While the unilingual children seemed to identify most objects as masculine, many younger bilingual children were willing to consider that, globally speaking, some objects could be feminine in nature even though, Nicoladis says, "their categorizations didn't correspond very well to whether the objects were masculine or feminine in French."
As to how Bessie may have inadvertently became Bernie, Nicoladis says that there is an explanation as to why the children may have chosen masculine more often than feminine, even for cows: it reveals a bias embedded in the language.
"Traditionally, in most languages -- and English is no exception -- the kind of default pronoun is a masculine pronoun," Nicoladis says. "If you read prescriptive grammar books, they might say 'everyone put on his coat' not 'everyone put on his or her coat.' The default, even when the gender isn't specified, is masculine."
No need to check under the hood
These gender-bending statements are no cause for panic. The researchers note that the identity issues were actually relatively common among the unilingual and bilingual kids, with French seeming to have only a small influence with pre-school children.
"What we found is that the monolingual children had a huge boy bias for all of the objects we asked them about," says Nicoladis. "Cats are girls, stars are girls." But to the participants, pretty much everything else was masculine, including cows. To the researchers, it said more about culture and language rather than factual knowledge.
Don't know much about biology…
Nicoladis says that the gender identification is not based on biological knowledge in the younger years. She notes that the older children she surveyed seemed able to reason that cows were the female members of the cattle clan, indicating their understanding of the biology of the animals. And, while some may be tempted to chalk it up to "kids saying the darndest things," some adults seemed to get a little mixed up, too.
"We found the same trends with adults who clearly should be able to reason about the biology," says Nicoladis. "But I think when you're just answering the question really fast, it's picking up some other aspect of their understanding of the world." The embedded bias towards the masculine pronoun was, in effect, trumping the obvious fact that cows are female.
Read more at Science Daily
Some of the more startling results from the Anglo crowd? Cows are boys. Cats and stars are girls.
Le culture or la culture: our bias
The researchers showed objects or images to the children participating in the study and asked them whether the objects seemed to be masculine or feminine in nature. While the unilingual children seemed to identify most objects as masculine, many younger bilingual children were willing to consider that, globally speaking, some objects could be feminine in nature even though, Nicoladis says, "their categorizations didn't correspond very well to whether the objects were masculine or feminine in French."
As to how Bessie may have inadvertently became Bernie, Nicoladis says that there is an explanation as to why the children may have chosen masculine more often than feminine, even for cows: it reveals a bias embedded in the language.
"Traditionally, in most languages -- and English is no exception -- the kind of default pronoun is a masculine pronoun," Nicoladis says. "If you read prescriptive grammar books, they might say 'everyone put on his coat' not 'everyone put on his or her coat.' The default, even when the gender isn't specified, is masculine."
No need to check under the hood
These gender-bending statements are no cause for panic. The researchers note that the identity issues were actually relatively common among the unilingual and bilingual kids, with French seeming to have only a small influence with pre-school children.
"What we found is that the monolingual children had a huge boy bias for all of the objects we asked them about," says Nicoladis. "Cats are girls, stars are girls." But to the participants, pretty much everything else was masculine, including cows. To the researchers, it said more about culture and language rather than factual knowledge.
Don't know much about biology…
Nicoladis says that the gender identification is not based on biological knowledge in the younger years. She notes that the older children she surveyed seemed able to reason that cows were the female members of the cattle clan, indicating their understanding of the biology of the animals. And, while some may be tempted to chalk it up to "kids saying the darndest things," some adults seemed to get a little mixed up, too.
"We found the same trends with adults who clearly should be able to reason about the biology," says Nicoladis. "But I think when you're just answering the question really fast, it's picking up some other aspect of their understanding of the world." The embedded bias towards the masculine pronoun was, in effect, trumping the obvious fact that cows are female.
Read more at Science Daily
Breaking the Code: Why Yuor Barin Can Raed Tihs
For emaxlpe, it deson't mttaer in waht oredr the ltteers in a wrod aepapr, the olny iprmoatnt tihng is taht the frist and lsat ltteer are in the rghit pcale. The rset can be a toatl mses and you can sitll raed it wouthit pobelrm.
S1M1L4RLY, Y0UR M1ND 15 R34D1NG 7H15 4U70M471C4LLY W17H0U7 3V3N 7H1NK1NG 4B0U7 17.
Passages like these have been bouncing around the Internet for years. But how do we read them? And what do our incredibly low standards for what's legible say about the way our brains work?
According to Marta Kutas, a cognitive neuroscientist and the director of the Center for Research in Language at the University of California, San Diego, the short answer is that no one knows why we're so good at reading garbled nonsense. But they've got strong suspicions.
"My guess is that context is very, very, very important," Kutas told Life's Little Mysteries.
We use context to pre-activate the areas of our brains that correspond to what we expect next, she explained. For example, brain scans reveal that if we hear a sound that leads us to strongly suspect another sound is on the way, the brain acts as if we're already hearing the second sound. Similarly, if we see a certain collection of letters or words, our brains jump to conclusions about what comes next. "We use context to help us perceive," Kutas said. [6 Fun Ways to Exercise Your Brain]
It's not a perfect system, however. In the above passages, Kutas suspects that you probably didn't get every single word right just from knowing what came before it. You onlythought you were reading the passage perfectly, because you automatically (and subconsciously) went back and filled in any gaps in your knowledge based on subsequent context — the words that came later.
Additionally, in the case of the first example (the words with jumbled middle letters), it helps that your brain processes all the letters of a word at once, rather than one at a time. Thus, the letters "serve as contexts for each other," Kutas said.
Read more at Discovery News
Wild Lions Live in Constant Fear
Lions have drastically changed the way they behave and perceive their environment because of new, numerous and deadly clashes with humans, according to a new study, published in the Journal of Applied Ecology,
“The ‘landscape of fear’ represents relative levels of predation risk as peaks and valleys that reflect the level of fear of predation an animal experiences in different parts of its territory,” lead author Marion Valeix of the University of Oxford’s Wildlife Conservation Research Unit, told Discovery News.
She and colleagues Graham Hemson, Andrew Loveridge, Gus Mills and David Macdonald explained that most prey animals live within a fearful mindset which keeps them on a constant, stressed out watch. Now even high-level predators may live this way too when they exist in or around human-dominated landscapes.
The researchers studied the behavior, foraging and territory of lions living in one of the last natural migratory systems, the Makgadikgadi Pans National Park in Botswana, where abundant packs of Burchell’s zebra and blue wildebeest live in different parts of the park on a seasonal basis.
Lands used by people for grazing their livestock surround the protected wilderness area. This creates a human-lion conflict, since when the zebra and wildebeest move en masse out of lion areas, many lions will resort to hunting livestock, such as cattle, to avoid losing established territories and reproductive loss, among other reasons.
GPS tracking of the lions determined that the major driver of lion behavior was the risk of conflict with humans. While the herders in Botswana do not always have easy access to firearms, some do.
Hemson said “we extracted lead shot from one lion in the study and another lion was shot in the spine and paralyzed. As such, we have evidence that lions may survive encounters with better armed people, and these surely make a lasting impression” on the other lions.
He does not think lions are born with this fear, since cubs are very inquisitive and would regularly follow his “vehicle and circle it and even test the bumper with their teeth and paws.” But through their mother and other pride members, they learn to fear humans as they grow up.
While a handful of very large protected areas, such as in Kalahari national parks, may permit lions to live without encroaching on human, “these areas are getting fewer and fewer,” Hemson said.
In Botswana, the researchers hope herders will reduce the abundance of livestock left unattended at night, since these attract lions that are looking for a meal but are also trying to avoid humans. They also call for overall improved livestock husbandry, which might include more consistent use of protective enclosures.
The scientists, however, lament that during this present difficult socio-economic time, such measures are not likely to be implemented anytime soon. They hope an incentive structure might be put into place for herders, providing them with financial and other rewards to make the improvements and to promote tolerance of lions and other wildlife.
Read more at Discovery News
Feb 9, 2012
Most Lethal Known Species of Prion Protein Identified
Scientists from the Florida campus of The Scripps Research Institute have identified a single prion protein that causes neuronal death similar to that seen in “mad cow” disease, but is at least 10 times more lethal than larger prion species.
This toxic single molecule or “monomer” challenges the prevailing concept that neuronal damage is linked to the toxicity of prion protein aggregates called “oligomers.”
The study was published this week in an advance, online edition of the journal Proceedings of the National Academy of Sciences.
“By identifying a single molecule as the most toxic species of prion proteins, we’ve opened a new chapter in understanding how prion-induced neurodegeneration occurs,” said Scripps Florida Professor Corinne Lasmézas, who led the new study. “We didn’t think we would find neuronal death from this toxic monomer so close to what normally happens in the disease state. Now we have a powerful tool to explore the mechanisms of neurodegeneration.”
In the study, the newly identified toxic form of abnormal prion protein, known as TPrP, caused several forms of neuronal damage ranging from apoptosis (programmed cell death) to autophagy, the self-eating of cellular components, as well as molecular signatures remarkably similar to that observed in the brains of prion-infected animals. The study found the most toxic form of prion protein was a specific structure known as alpha-helical.
New Paths to Explore
In addition to the insights it offers into prion diseases such as “mad cow” and a rare human form Creutzfeldt-Jakob disease, the study opens the possibility that similar neurotoxic proteins might be involved in neurodegenerative disorders such as Alzheimer’s and Parkinson diseases.
In prion disease, infectious prions (short for proteinaceous infectious particles), thought to be composed solely of protein, have the ability to reproduce, despite the fact that they lack DNA and RNA. Mammalian cells normally produce what is known as cellular prion protein or PrP; during infection with a prion disease, the abnormal or misfolded protein converts the normal host prion protein into its disease form.
Lasmézas explains that prion diseases are similar to Alzheimer's and other protein misfolding diseases in that they are caused by the toxicity of a misfolded host protein. Recent work, as reported in The New York Times, also found that diseases such as Alzheimer's resemble prion diseases by spreading from cell to cell.
Read more at Science Daily
This toxic single molecule or “monomer” challenges the prevailing concept that neuronal damage is linked to the toxicity of prion protein aggregates called “oligomers.”
The study was published this week in an advance, online edition of the journal Proceedings of the National Academy of Sciences.
“By identifying a single molecule as the most toxic species of prion proteins, we’ve opened a new chapter in understanding how prion-induced neurodegeneration occurs,” said Scripps Florida Professor Corinne Lasmézas, who led the new study. “We didn’t think we would find neuronal death from this toxic monomer so close to what normally happens in the disease state. Now we have a powerful tool to explore the mechanisms of neurodegeneration.”
In the study, the newly identified toxic form of abnormal prion protein, known as TPrP, caused several forms of neuronal damage ranging from apoptosis (programmed cell death) to autophagy, the self-eating of cellular components, as well as molecular signatures remarkably similar to that observed in the brains of prion-infected animals. The study found the most toxic form of prion protein was a specific structure known as alpha-helical.
New Paths to Explore
In addition to the insights it offers into prion diseases such as “mad cow” and a rare human form Creutzfeldt-Jakob disease, the study opens the possibility that similar neurotoxic proteins might be involved in neurodegenerative disorders such as Alzheimer’s and Parkinson diseases.
In prion disease, infectious prions (short for proteinaceous infectious particles), thought to be composed solely of protein, have the ability to reproduce, despite the fact that they lack DNA and RNA. Mammalian cells normally produce what is known as cellular prion protein or PrP; during infection with a prion disease, the abnormal or misfolded protein converts the normal host prion protein into its disease form.
Lasmézas explains that prion diseases are similar to Alzheimer's and other protein misfolding diseases in that they are caused by the toxicity of a misfolded host protein. Recent work, as reported in The New York Times, also found that diseases such as Alzheimer's resemble prion diseases by spreading from cell to cell.
Read more at Science Daily
Black Hole Eats Asteroids, Burps Out X-Rays
Though nothing, including light, can escape a black hole, most are ringed by a disk of gas and dust. As it falls in, this material heats up to incredible temperatures, generating energy.
For several years, NASA’s Chandra X-ray Observatory has spotted daily fluctuations in the emissions coming from the Milky Way’s central black hole. Known as Sagittarius A*, this 2-million- to 4-million-solar-mass black hole is approximately 26,000 light-years from Earth near the border of the constellations Sagittarius and Scorpius.
Sagittarius A*’s daily flares generally last a few hours and increase the black hole’s brightness by a hundred times. Scientists have been at a loss to explain why the black hole would have such regular eruptions.
Researchers now suggest that tens of trillions of asteroids and comets, stolen from their parent stars, might float around the black hole. If a 12-mile-wide (or larger) asteroid should get within 100 million miles of the black hole, tidal forces would rip it to shreds. These fragments would then fall in and be vaporized by friction as they encounter the gas and dust churning around the black hole.
The central supermassive black hole could sustain these regular flares for billions of years. Even at a rate of one asteroid per day, it would have only consumed a few trillion asteroids over the lifetime of the galaxy, leaving plenty of fodder.
An unfortunate planet coming loose from its parent star could also get ripped apart in this manner. Because planets are far less numerous than asteroids, this process would be much rarer. Were a planet to be eaten, it would produce a dramatic flare, brightening the black hole by a million times its normal output.
Read more at Wired Science
How The Zebra Got Its Stripes
But while Kipling addressed the leopard's spots and the camel's hump, he never explained the zebra's stripes. A new study helps fill in the void, this time with actual data.
Casting aside a long list of possible explanations, the new research proposes that a zebra's bold pattern of black and white stripes reflects light in a way that helps the animals evade disease-infested flies.
Hungry flies might not be the only force that pushed zebras to develop stripes. But the findings might offer new strategies for defending animals, and even people, against some insects.
"We have been breeding animals based on meat or milk production, and we haven’t paid much attention to their coat colorations or patterns," said Susanne Åkesson, an evolutionary ecologist at Lund University in Sweden. "Maybe it's something we need to consider. Maybe there's some trick we can learn form the zebra that could help."
Scientists have been speculating about the purpose of the zebra's stripes since the 1870s, when Charles Darwin criticized Alfred Russel Wallace's theory that the stripes provided camouflage in tall grass. Zebras prefer open savannahs, Darwin argued, where the grass is too short to make stripes useful hiding tools.
Since then, theories have invoked zebra-to-zebra recognition, defense against lions who can't pick out an individual zebra from amongst a mass of stripes, and thermoregulation -- as the patterns of dark and light fur might cause air turbulence, helping cool the animals off.
Åkesson and colleagues wondered if horseflies, which belong to a group called tabanids, might have something to do with the story. These flies are major pests for zebras, cows, horses and related animals. Their bites can be irritating enough to reduce grazing. And they can carry deadly diseases.
In previous work, Åkesson and her team had found that horseflies are more attracted to dark animals than to white ones, likely because of the way that light reflects off of different surfaces. Direct sunlight is full of rays that shine in all directions. But when sunlight bounces off of water -- or off of a dark brown horse or cow -- its reflections align horizontally.
Tabanid flies are attracted to this kind of linearly polarized light: It often leads them to water, where they can lay their eggs and mate. Just as often, though, their polarized light sense leads them to large animals, which they bite and annoy to no end.
Since zebras are both dark and light, the researchers wondered if these striking animals might have an intermediate-level of attractiveness to flies. To find out, they conducted a series of experiments with oil-filled trays, odorless insect tape-covered panels and zebra-like plastic models that where black or brown, white or striped.
Every day for a few weeks during the summer on a Hungarian horse farm, flies flew to their preferred color patterns and got trapped, allowing the researchers to collect the insects, count them and gauge their preferences.
As expected, very few flies landed on the white surfaces, the researchers report today in the Journal of Experimental Biology, while hundreds went for the black objects in some cases. Surprisingly, the striped objects attracted just as few -- and sometimes fewer -- flies than the white surfaces did. More flies landed on black stripes than on white stripes.
When the researchers made the black stripes wider than a typical zebra's pattern, objects attracted more flies. Measurements confirmed that the most polarized surfaces attracted the most insects.
Given the major advantage that zebras would get by avoiding fly bites that could kill them before they reproduced, Åkesson said, the paper offers a strong argument that stripes developed to protect the animals against insects and their diseases.
As solid as the new data is, though, the story is far from over, said Tim Caro, a behavioral ecologist at the University of California, Davis, who is writing a book about the evolution of the zebra's looks.
If stripes are so helpful, for example, why aren't all Eurasian horses striped? Meanwhile, studies have yet to carefully examine most of the other theories about zebra evolution. There might be many reasons why they are black and white.
Animal coloration has a long history of inspiring applications in military and other situations, Caro said, pointing to the black-and-white geometric patterns that decorated navy ships with "dazzle camouflage" during World War I. Still, studies like the new one may have their biggest impact on young minds, sparking excitement about science and the natural world.
Read more at Discovery News
Large Meteorite Likely Found in Druid Burial Site
The giant rock, spanning about 1.6 feet (0.5 meters) across and weighing 205 pounds (93 kilograms), was likely discovered by an archaeologist about 200 years ago at a burial site created by the Druids (an ancient Celtic priesthood) near Stonehenge, according to said Colin Pillinger, a professor of planetary sciences at the Open University.
Pillinger curated the exhibition "Objects in Space," which opened Feb. 9 and is the first time the public will get a chance to see the meteorite. The exhibition will explore not only the mystery that surrounds the origins of the giant meteorite, but also the history and our fascination with space rocks.
As for how the meteorite survived its long stint on Earth, researchers point to the ice age.
"The only meteorites that we know about that have survived these long ages are the ones that were collected in Antarctica," said Pillinger, adding that more recently, some ancient meteorites have been collected in the Sahara Desert. This rock came from neither the Sahara Desert nor Antarctica, but rather the Lake House in Wiltshire.
"Britain was under an ice age for 20,000 years," Pillinger told LiveScience, explaining the climate would have protected the rock from weathering.
At some point, the Druids likely picked up the meteorite when scouting for rocks to build burial chambers. "They were keen on building burial sites for [the dead] in much the same way the Egyptians built the pyramids," Pillinger said.
Then, years later, an archaeologist with ties to other, famous archaeologists, likely found the rock while excavating the Druids' burial sites, he said. The archaeologist then brought the rock back to his house in Wiltshire, where its more recent residents took notice and alerted researchers.
"The men whose house this was found at spent a lot of time opening these burial sites 200 years ago for purposes of excavating them," Pillinger said. "Our hypothesis is that the stone probably came out of one of those burial chambers."
The meteorite is called a chondrite, a group that includes primitive meteorites that scientists think were remnants shed from the original building blocks of planets. Most meteorites found on Earth fit into this group.
Read more at Discovery News
Feb 8, 2012
Dogs Really Do Understand Us Best
The study in the latest issue of PLoS ONE. found that chimpanzees could care less when people pointed to objects, but dogs paid attention and knew precisely what the person wanted.
“We think that we are looking at a special adaptation in dogs to be sensitive to human forms of communication,” co-author Juliane Kaminski, a cognitive psychologist at the Max Planck Institute for Evolutionary Anthropology, told Discovery News. “There is multiple evidence suggesting that selection pressures during domestication have changed dogs such that they are perfectly adapted to their new niche, the human environment.”
Dogs may even be born with this inherent gift, since 6-week-old puppies with no major training possess it.
For the study, Kaminski and her colleagues compared how well chimpanzees and dogs understood human pointing. The person pointed at a visible object out of reach of the human but within reach of the animal subject. If the chimp or dog retrieved the object, he or she would be rewarded with a tasty food treat. (Chimps received fruit juice or peanuts, while dogs got dry dog food.)
The chimps bombed, ignoring the human gestures, even though they were interested and motivated to get the food rewards. The dogs aced the test.
The chimpanzees failed to comprehend the referential intention of the human in the task. They did not see the pointing as important to their goal of getting the food, so they simply ignored the people during the study.
“We know that chimpanzees have a very flexible understanding of others,” Kaminski said. “They know what others can or cannot see, when others can or cannot see them, etc.”
Chimps are therefore not clueless, but they have likely not evolved the tendency to pay attention to humans when trying to achieve goals.
Kaminski explained that even wolves do not have this skill.
“Wolves, even when raised in a human environment, are not as flexible with human communication as dogs,” she said. “Dogs can read human gestures from very early ages on.”
As for cats, prior research found that domesticated felines also pay attention to us and can understand human pointing gestures. Kaminski, however, mentioned that “the researchers had to select them out of many hundreds of cats, “ suggesting that only certain house kitties are on par with dogs when it comes to understanding people.
The breed of the animal may also factor in, according to Márta Gácsi, from Eötvös University, Hungary. Gácsi worked with a team of researchers to examine the performance of different breeds of dogs in making sense of the human pointing gesture.
The scientists found that gun dogs and sheep dogs were better than hunting hounds, earth dogs (dogs used for underground hunting), livestock guard dogs and sled dogs at following a pointing finger.
Read more at Discovery News
Tiny Primate Communicates Secretly in Ultrasound
The distinctive tiny tarsier possesses large eyes relative to its body as well as the world's highest frequency primate call. Hear that call here.
"Tarsiers are among only a handful of mammals that are known to communicate in the pure ultrasound,” lead author of a paper in the Royal Society's Biology Letters, Marissa Ramsier, told Discovery News. "No other primate is known to produce and detect signals as high as the tarsier."
Ramsier, co-director of the Biological Anthropology Research Lab at Humboldt State University, and her colleagues, made the determination after studying six tarsiers that were captured in the vicinity of Motorpool, Surigao del Norte, Mindanao, Philippines.
To estimate auditory sensitivities, the researchers first used a minimally invasive brainstem response test. This showed that the primates can hear in the ultrasound range, up to 91 kHz. For comparison, humans have a high-frequency detection limit of only about 20 kHz.
Next, the scientists recorded vocalizations made by the tarsiers. In some cases, the tarsiers were opening and closing their mouths, looking like they were communicating, but no sound was heard. Sensitive high tech recording equipment revealed that the primates were indeed communicating, but in ultrasound frequencies.
Philippine tarsiers join a select group of mammals that have this ability. The group includes certain bats, rodents, cetaceans and even domestic cats. Ramsier explained that "kittens produce a pure ultrasonic call from about 2-6 weeks of life when they are first exploring their environment, and a mother cat produces its own purely ultrasonic call in response to the kitten." Cats at these times of life can therefore communicate in ways not detected by their owners, "unless they follow them around with a bat detector."
All of these ultrasound-producing animals can then communicate within their own private "channel," which could prevent detection by predators, prey and competitors. It could also enhance energetic efficiency and improve detection against low-frequency background noise.
Humans, on the other hand, may have no evolutionary advantage to producing and detecting ultrasound.
"Humans are big and noisy," Ramsier said. "If a predator is nearby, it will likely see and hear us."
Conversely, tarsiers are small and active during the night, so it is relatively easy for them to use masked vocalizations as a covert strategy. Ramsier thinks they do this by constriction of their larynx and rapid opening and closing of their vocal chords. They probably have special auditory features that enable hearing of ultrasound.
Chris Kirk, an associate professor in the department of anthropology at the University of Texas at Austin, told Discovery News that this "study is important because it expands the number of primate species that concentrate a large part of the acoustic energy in their vocal communications within the ultrasonic range."
Read more at Discovery News
Perpetrator of Galactic Hit-and-Run Found
The evidence exonerates another previously known companion galaxy, DDO 125, which is located about 130,000 light years away from NCG 4449. Instead, new observations of NGC 4449 taken between May 29 and June 1, 2011 (made in the course of commissioning a new 0.7-meter telescope at Saturn Lodge Observatory, Calif.) turned up what scientists call "a profoundly tidally distorted" dwarf galaxy NGC 4449B.
The new companion lies about 29,000 light years from the center of NGC 4449. Computer models show the contorted shapes of the two galaxies fit.
"We speculate that NGC 4449B is on its first encounter with NGC 4449 and experienced a close passage near the nucleus of NGC 4449," lead researcher Michael Rich, with the University of California, Los Angeles, writes in this week's Nature.
"This conclusion is supported by the morphology of NGC 4449B, the plume pointing at the nucleus, and the approximate agreement with the structure and timescales of the simulation," Rich wrote.
Read more at Discovery News
Look North for the Next Supercontinent Amasia
As with anything new related to geology, looking forward requires scrutinizing the almost unimaginable past. The dominant hypothesis is that Earth's first supercontinent, Rodinia, formed 1.1 billion years ago. Plates shifted, more stuff happened, a land called Gondwana united, more stuff happened again, and then a mere 250 million years ago, Pangea came together.
Over time, rifting tore this giant supercontinent apart and the puzzle pieces scattered across the globe looking more like the continents we know. Keep in mind this is all dramatically happening at speeds about as fast as your fingernails grow.
Since the 1990s, several well-known models for a future supercontinent have been introduced. Harvard University geologist Paul Hoffman was the first to dub one version "Amasia." Until now there had been two dominant models of how and where Amasia will form. Both predicted the landmasses to converge along the equator, but differed on whether it would happen in the same place as Pangea was before or on the other side of the world.
Yale University geology and geophysics professor David Evans, along with graduate students Taylor Kilian and Ross N. Mitchell, studied the magnetism in ancient rocks to figure out where they were positioned and measured how the material under continents are moving the masses.
"The Americas will remain in the Pacific ‘ring of fire’ girdle of post-Pangaean subduction, closing the Arctic Ocean and Caribbean Sea," the Yale geophysicists wrote in a Nature journal article published today. In other words, they think Amasia will form over the Arctic, 90 degrees away from the original Pangea.
To geologists, the Yale group's idea makes sense. After all, previous supercontinents appear to have formed successively at 90 degrees to each other.
Read more at Discovery News
Feb 7, 2012
Ovarian Cancer Risk Related to Inherited Inflammation Genes
In a study conducted by researchers at Moffitt Cancer Center and colleagues from 11 other institutions in the Unites States and the United Kingdom, genes that are known to be involved in inflammation were found to be related to risk of ovarian cancer.
Their study appeared in a recent issue of Cancer Research, published by the American Association for Cancer Research.
Chronic inflammation is known to influence risk of several cancers, including ovarian cancer. The researchers identified 27 genes that are involved in inflammation and sought to determine whether inter-individual differences in these genes were related to risk of ovarian cancer. To do that they determined the frequency of 162 single-nucleotide polymorphisms (SNPs, pronounced "snips") in DNA extracted from a blood sample provided by approximately 900 women with ovarian cancer (cases) and 1000 cancer-free women (controls). Whenever a SNP is observed it means that there are two forms (alleles) of the gene and the least common one is termed the "minor allele." The frequency of 21 of the 162 SNPs differed between the cases and controls and was subsequently examined in a larger study that included 3,100 cases and 2,100 controls from five independent studies.
"When we examined the relationship between SNPs in inflammation-related genes and the risk of ovarian cancer, we found variants in five of the 27 genes were related to risk. What was interesting to us was that women who carried the minor alleles had lower ovarian cancer risk. Each SNP appeared to lower risk by about 10 percent," explained study co-author Thomas A. Sellers, Ph.D., M.P.H., Moffitt executive vice president and director of the Moffitt Research Institute.
One of the genes encodes Interleuken 1 alpha (IL1A), a cytokine, or a small signaling protein molecule that is involved in numerous immune and inflammatory responses, said the authors. IL1A has been associated with many inflammatory response conditions and diseases. In this study, the researchers found that IL1A, and another gene, AloX5, "appear to harbor common inherited variants associated with modest differences in the risk of ovarian cancer."
"The importance of inflammation pathways in the development of many cancers prompted us to examine this association between SNPS in inflammation-related genes and risk for ovarian cancer," explained Sellers. "If these results can be confirmed, it might provide insights into how risk may be reduced, through strategies to lower chronic inflammation."
The authors noted that in 2011 there were an estimated 225,500 new cases of ovarian cancer worldwide. Although some women are at greatly elevated risks of ovarian cancer due to inherited mutations in the BRCA1 and BRCA2 genes, these are rare in the population and account for perhaps 10 percent of cases. However, a substantial portion of genetic influence on ovarian cancer risk has been "unexplained" and some of that may be due to common genetic variants. Sellers points out that "the Il1A variant that was most strongly protective is carried by 30 percent of women in the study, so the impact at the population level is not trivial."
Read more at Science Daily
Their study appeared in a recent issue of Cancer Research, published by the American Association for Cancer Research.
Chronic inflammation is known to influence risk of several cancers, including ovarian cancer. The researchers identified 27 genes that are involved in inflammation and sought to determine whether inter-individual differences in these genes were related to risk of ovarian cancer. To do that they determined the frequency of 162 single-nucleotide polymorphisms (SNPs, pronounced "snips") in DNA extracted from a blood sample provided by approximately 900 women with ovarian cancer (cases) and 1000 cancer-free women (controls). Whenever a SNP is observed it means that there are two forms (alleles) of the gene and the least common one is termed the "minor allele." The frequency of 21 of the 162 SNPs differed between the cases and controls and was subsequently examined in a larger study that included 3,100 cases and 2,100 controls from five independent studies.
"When we examined the relationship between SNPs in inflammation-related genes and the risk of ovarian cancer, we found variants in five of the 27 genes were related to risk. What was interesting to us was that women who carried the minor alleles had lower ovarian cancer risk. Each SNP appeared to lower risk by about 10 percent," explained study co-author Thomas A. Sellers, Ph.D., M.P.H., Moffitt executive vice president and director of the Moffitt Research Institute.
One of the genes encodes Interleuken 1 alpha (IL1A), a cytokine, or a small signaling protein molecule that is involved in numerous immune and inflammatory responses, said the authors. IL1A has been associated with many inflammatory response conditions and diseases. In this study, the researchers found that IL1A, and another gene, AloX5, "appear to harbor common inherited variants associated with modest differences in the risk of ovarian cancer."
"The importance of inflammation pathways in the development of many cancers prompted us to examine this association between SNPS in inflammation-related genes and risk for ovarian cancer," explained Sellers. "If these results can be confirmed, it might provide insights into how risk may be reduced, through strategies to lower chronic inflammation."
The authors noted that in 2011 there were an estimated 225,500 new cases of ovarian cancer worldwide. Although some women are at greatly elevated risks of ovarian cancer due to inherited mutations in the BRCA1 and BRCA2 genes, these are rare in the population and account for perhaps 10 percent of cases. However, a substantial portion of genetic influence on ovarian cancer risk has been "unexplained" and some of that may be due to common genetic variants. Sellers points out that "the Il1A variant that was most strongly protective is carried by 30 percent of women in the study, so the impact at the population level is not trivial."
Read more at Science Daily
World's First Animals Were Namibian Sponges
That means animals, previously thought to have emerged 600 million to 650 million years ago, actually appeared 100 million to 150 million years before that, the authors said.
It also means the hollow globs -- about the size of a dust speck and covered in holes that allowed fluid to pass in and out of their bodies -- were our ancestors, said co-author Tony Prave, a geologist at the University of St Andrews in Scotland.
"If one looks at the family tree and projects this backward to where you have what's called the stem group, the ancestor of all animals, then yes, this would be our great-great-great-great-great-great-great grandmother," he told AFP.
Prave said fossil evidence that animals emerged as long as 760 million years ago fit together neatly with what geneticists had hypothesised by looking at "molecular clocks", a means of gauging a species' age by looking at the percentage difference between its DNA and that of another species.
Read more at Discovery News
Our Planet, Tangled in Magnetic Spaghetti
Using the awesome power of a Cray XT5 Jaguar supercomputer, a team of space physicists are unlocking some of the biggest mysteries surrounding how the sun's magnetic field interacts with our planet's magnetosphere. They basically want to understand what happens when global magnetic fields become tangled to the extreme.
Space physicists categorize these interactions under "space weather," and they are responsible for some of the Earth's most powerful (and beautiful) atmospheric events.
"When a storm goes off on the sun, we can't really predict the extent of damage that it will cause here on Earth. It is critical that we develop this predictive capability," said Homa Karimabadi, a space physicist at the University of California-San Diego (UCSD).
Computer simulations are a critical tool for space weather prediction, and with the help of one of the most powerful supercomputers in the world (that is capable of a peak performance of 2.33 petaFLOPS), the complex magnetohydrodynamics of a geomagnetic storm can be better understood.
It's All In The Magnetic Fluid Motion
Put very simply, the tough physics behind "magnetohydrodynamics" can be split into three parts: magneto = magnetic, hydro = fluid, dynamics = motion. Each part represents complex calculations of how space plasma -- from the hot, glowing, turbulent plasma on the solar surface, to the tenuous, wispy, high-energy ions that makes up the solar wind -- acts.
So, should the sun unleash a coronal mass ejection (CME) in the direction of Earth (like it did at the end of last month), it would be useful to model the impact of this magnetic bubble of high-energy plasma before it hits our magnetosphere. Such an event involves a lot of magnetic-fluid-motion!
"With petascale computing we can now perform 3D global particle simulations of the magnetosphere that treat the ions as particles, but the electrons are kept as a fluid," said Karimabadi. "It is now possible to address these problems at a resolution that was well out of reach until recently."
With all this computing power, Karimabadi and his team have been able to simulate the phenomenon of "magnetic reconnection" -- a phenomenon that can occur when two magnetic fields are forced together. The physics are hard to interpret, so the plasma needs to be simulated as a fluid and individual particles, all responding to the presence of a magnetic field.
Should the conditions be "just right" during a solar storm, for example, the magnetic field of an incoming CME and the magnetosphere may be aligned -- or "geo-effective" -- so that the two fields snap and reconnect, creating an entry point for energetic solar particles to flood into the outer layers of the Earth's magnetic field. Geomagnetic storms are often the result, generating stunning aurorae at high latitudes and powerful electrical currents through the atmosphere.
These electrical currents can cause problems on the ground, especially if we are caught unprepared. Predicting the occurrence of these currents are very useful to power companies, say. Should a "geo-effective" CME thump the magnetosphere, they'll know a geomagnetic storm is coming and managers may decide to take measures to avoid power outages.
Key to understanding how the plasma and magnetic field from the sun interacts with our magnetosphere is to understand the amount of turbulence generated during a CME impact. "One of the surprising outcomes of our research is the ubiquity and nature of turbulence in the magnetosphere," said Karimabadi. "This is important since turbulence implies more efficient mixing of the plasma and fields, and after all, space weather arises because the plasma and fields emanating from the sun can penetrate and mix with the plasma and fields of Earth's magnetosphere."
Read more at Discovery News
Strange Life Found in Underwater Caves
The caves in question are called "blue holes," so-named because from the air, their entrances appear circular in shape, with different shades of blue water in and around them. There are estimated to be more than 1,000 such caves in the Bahamas, the greatest concentration of blue holes in the world.
"It's really incredible to be swimming down a passage that no one has ever been in before, to experience that thrill of discovery," said researcher Tom Iliffe, a marine biologist at Texas A&M University at Galveston. "At the bottom of a cave, there's no telling what might be around the next corner."
Iliffe and his colleagues examined three inland blue holes in the Bahamas. They discovered that layers of bacteria exist in all three, but each of these water-filled sinkholes had significantly different microbes living in them from the others.
"We're finding new forms of life that are totally unknown elsewhere on Earth," Iliffe told OurAmazingPlanet.
Blue hole bacteria
Within each blue hole, the microbes the researchers found varied depending on the depth, owing to how the water in them was separated into distinct fresh- and saltwater layers as well as oxygen-poor or virtually completely oxygen-depleted layers. The blue holes also varied from each other due to differences such as food sources.
"We examined two caves on Abaco Island and one on Andros Island," Iliffe said. "One on Abaco, at a depth of about 100 feet (30 meters), had sheets of bacteria that were attached to the walls of the caves, almost one inch (2.5 centimeters) thick. Another cave on the same island had bacteria living within poisonous clouds of hydrogen sulfide at the boundary between fresh- and saltwater. These caves had different forms of bacteria, with the types and density changing as the light source from above grew dimmer and dimmer."
"In the cave on Andros, we expected to find something similar, but the hydrogen sulfide layer there contained different types of bacteria," Iliffe added. "It shows that the caves tend to have life forms that adapt to that particular habitat, and we found that some types of the bacteria could live in environments where no other forms of life could survive. This research shows how these bacteria have evolved over millions of years and have found a way to live under these extreme conditions." [Harshest Environments on Earth]
'Natural laboratories'
The fact that each cave has different conditions from the others and thus a different palette of life helps scientists analyze the diverse routes life might have taken on Earth, given slight tweaks in their initial brews.
"These bacterial forms of life may be similar to microbes that existed on early Earth and thus provide a glimpse of how life evolved on this planet," Iliffe explained. "These caves are natural laboratories where we can study life existing under conditions analogous to what was present many millions of years ago."
Specifically, "these caves have no light and therefore no photosynthetic production of oxygen, which means the dissolved oxygen levels are either low or nonexistent, similar to the environments that probably existed on the early Earth," Iliffe said.
These findings might also shed light on how life might have developed on distant planets and moons.
"As far as we know, no surface waters currently exist anywhere else in our solar system, but there might be water beneath the surface, say on Mars or moons like Europa," Iliffe said. "These are areas of total darkness, and so the caves on Earth we are exploring might be similar."
Read more at Discovery News
Feb 6, 2012
East Views the World Differently to West
Cultural differences between the West and East are well documented, but a study shows that concrete differences also exist in how British and Chinese people recognise people and the world around them. Easterners really do look at the world differently to Westerners, according to new research funded by the Economic and Social Research Council (ESRC).
"British and Chinese people process visual information in very different ways," explains researcher Dr David Kelly from Royal Holloway, University of London. "This is important not simply from a research viewpoint, but because it helps us understand much better some of the cultural differences between East and West which people can sometimes find disconcerting."
For example, while most British people look at a person's eyes when they are talking to them, Chinese people are much less likely to make eye contact. "This can leave the British person feeling uncomfortable and distrustful," Dr Kelly points out. "On the other hand, the Chinese person would consider eye contact to be potentially disrespectful and impolite."
Research now suggests that this particular cultural contrast is underpinned by the different ways Westerners (British) and Easterners (Chinese) 'process' visual information. While adults from Western cultures process information analytically by focusing on key features, adults from the East process information in a more holistic style, which also takes context and situation into account.
In terms of eye contact for example, this means that when a Westerner processes a person's face they will typically fixate on the key feature of the face, usually the eyes. An Easterner, in contrast, will largely avoid the eyes (hence the lack of eye contact) and take in information from a wider area below the eyes and around the nose. Interestingly, the studies also show that when asked to recognise other unfamiliar stimuli, such as sheep faces, Westerners and Easterners continue to employ their different face processing strategies in animals.
The researchers also explored when the learning of socio-cultural processing strategies took place by carrying out a series of visual processing studies with British and Chinese children, aged five to 12.
"If culture is responsible for shaping the way visual information is extracted and processed, then it is reasonable to assume that the strategies observed in Eastern adults emerge during childhood," Dr Kelly points out. "And our research showed this to be the case. Both British and Chinese children showed only minimal or no differences in processing strategies at the youngest age groups of five and six years year olds, but the different ways of processing visual information had emerged by the age of 12."
Read more at Science Daily
"British and Chinese people process visual information in very different ways," explains researcher Dr David Kelly from Royal Holloway, University of London. "This is important not simply from a research viewpoint, but because it helps us understand much better some of the cultural differences between East and West which people can sometimes find disconcerting."
For example, while most British people look at a person's eyes when they are talking to them, Chinese people are much less likely to make eye contact. "This can leave the British person feeling uncomfortable and distrustful," Dr Kelly points out. "On the other hand, the Chinese person would consider eye contact to be potentially disrespectful and impolite."
Research now suggests that this particular cultural contrast is underpinned by the different ways Westerners (British) and Easterners (Chinese) 'process' visual information. While adults from Western cultures process information analytically by focusing on key features, adults from the East process information in a more holistic style, which also takes context and situation into account.
In terms of eye contact for example, this means that when a Westerner processes a person's face they will typically fixate on the key feature of the face, usually the eyes. An Easterner, in contrast, will largely avoid the eyes (hence the lack of eye contact) and take in information from a wider area below the eyes and around the nose. Interestingly, the studies also show that when asked to recognise other unfamiliar stimuli, such as sheep faces, Westerners and Easterners continue to employ their different face processing strategies in animals.
The researchers also explored when the learning of socio-cultural processing strategies took place by carrying out a series of visual processing studies with British and Chinese children, aged five to 12.
"If culture is responsible for shaping the way visual information is extracted and processed, then it is reasonable to assume that the strategies observed in Eastern adults emerge during childhood," Dr Kelly points out. "And our research showed this to be the case. Both British and Chinese children showed only minimal or no differences in processing strategies at the youngest age groups of five and six years year olds, but the different ways of processing visual information had emerged by the age of 12."
Read more at Science Daily
It's Not Solitaire: Brain Activity Differs When One Plays Against Others
"When players compete against each other in a game, they try to make a mental model of the other person's intentions, what they're going to do and how they're going to play, so they can play strategically against them," said University of Illinois postdoctoral researcher Kyle Mathewson, who conducted the study as a doctoral student in the Beckman Institute with graduate student Lusha Zhu and economics professor and Beckman affiliate Ming Hsu, who now is at the University of California, Berkeley. "We were interested in how this process happens in the brain."
Previous studies have tended to consider only how one learns from the consequences of one's own actions, called reinforcement learning, Mathewson said. These studies have found heightened activity in the basal ganglia, a set of brain structures known to be involved in the control of muscle movements, goals and learning. Many of these structures signal via the neurotransmitter dopamine.
"That's been pretty well studied and it's been figured out that dopamine seems to carry the signal for learning about the outcome of our own actions," Mathewson said. "But how we learn from the actions of other people wasn't very well characterized."
Researchers call this type of learning "belief learning."
To better understand how the brain processes information in a competitive setting, the researchers used functional magnetic resonance imaging (fMRI) to track activity in the brains of participants while they played a competitive game, called a Patent Race, against other players. The goal of the game was to invest more than one's opponent in each round to win a prize (a patent worth considerably more than the amount wagered), while minimizing one's own losses (the amount wagered in each trial was lost). The fMRI tracked activity at the moment the player learned the outcome of the trial and how much his or her opponent had wagered.
A computational model evaluated the players' strategies and the outcomes of the trials to map the brain regions involved in each type of learning.
"Both types of learning were tracked by activity in the ventral striatum, which is part of the basal ganglia," Mathewson said. "That's traditionally known to be involved in reinforcement learning, so we were a little bit surprised to see that belief learning also was represented in that area."
Belief learning also spurred activity in the rostral anterior cingulate, a structure deep in the front of the brain. This region is known to be involved in error processing, regret and "learning with a more social and emotional flavor," Mathewson said.
The findings offer new insight into the workings of the brain as it is engaged in strategic thinking, Hsu said, and may aid the understanding of neuropsychiatric illnesses that undermine those processes.
Read more at Science Daily
You Can Listen to a Jurassic Love Song
The song was reconstructed from microscopic wing features on a fossil discovered in North East China. It allows us to listen to one of the sounds that would have been heard by dinosaurs and other creatures roaming Jurassic forests at night.
A veritable symphony of natural sounds must have filled the world 165 million years ago, with primitive crickets and croaking amphibians leading the way. These were among the first animals to produce loud sounds by stridulation, or rubbing certain body parts together. (We humans can do a version of this too, as this fellow demonstrates.)
Katydids produce mating calls by rubbing a row of teeth on one wing against an appendage on the other wing, but how their primitive ancestors produced sound and what their songs actually sounded like was unknown until now.
The research began when a team of palaeontologists, including Jun-Jie Gu and Dong Ren from the Capital Normal University in Beijing, contacted Fernando Montealegre-Zapata and Daniel Robert, both experts in the biomechanics of singing and hearing in insects, in Bristol's School of Biological Sciences. The group also teamed up with Michael Engel of the University of Kansas, a leading expert on insect evolution.
The researchers from Beijing provided an exceptionally well preserved katydid fossil from the Mid Jurassic period. The specimen had such clearly defined wing features that the details of its stridulating organs were visible under an optical microscope. Such information has never been fully obtained before from insect fossils. It was identified as a new fossil species and named Archaboilus musicus by the Beijing-Kansas team.
The Bristol scientists examined the anatomical construction of the fossil's song apparatus, and compared it to 59 living katydid species. They concluded that this animal must have produced musical songs by broadcasting pure, single frequencies.
"This discovery indicates that pure tone communication was already exploited by animals in the middle Jurassic, some 165 million years ago," Robert was quoted as saying in a press release. "For Archaboilus, as for living bushcricket (katydid) species, singing constitutes a key component of mate attraction. Singing loud and clear advertises the presence, location and quality of the singer, a message that females choose to respond to – or not."
He added, "Using a single tone, the male’s call carries further and better, and therefore is likely to serenade more females. However, it also makes the male more conspicuous to predators if they have also evolved ears to eavesdrop on these mating calls."
The researchers believe that A. musicus sang a tone pitched at 6.4kHz and that every bout of singing lasted 16 milliseconds.
"Using a low-pitched song, A. musicus was acoustically adapted to long-distance communication in a lightly cluttered environment, such as a Jurassic forest," Montealegre-Zapata said. "Today, all species of katydids that use musical calls are nocturnal so musical calls in the Jurassic were also most likely an adaptation to nocturnal life. Being nocturnal, Archaboilus musicus probably escaped from diurnal predators like Archaeopterix, but it cannot be ruled out that Jurassic insectivorous mammals like Morganucodon and Dryolestes also listened to the calls of Archaboilus and preyed on them."
Read more at Discovery News
They Did It! Russians Expose Lake Vostok Secrets
Attached was a link to the state-sponsored Russian news agency RIA Novosti, which quoted an unnamed source as saying:
Yesterday, our scientists stopped drilling at the depth of 3,768 meters and reached the surface of the sub-glacial lake.
The news came as a huge relief after weekend speculation grew over the current status of the Russian drill team as they raced against time to reach Antarctica's 20 million-year-old, ice-covered Lake Vostok or be forced to wait another year to try again.
Fox News was the first to call out the radio silence from the Russian drillers:
"No word from the ice for 5 days," Dr. John Priscu -- professor of ecology at Montana State University and head of a similar Antarctic exploration program -- told FoxNews.com via email.
Fox News was following up on an earlier status update Priscu provided the Washington Post on Feb. 1:
Priscu said Russian scientists on the scene e-mailed him last week to say they had stopped drilling about 40 feet from the expected waterline to measure the pressure levels deep below. Priscu said he expected that they were also sending down a special “hot water” drill to make the final push, but a message from the Russian team Monday reported “no news.”
Enter an explanation on what happens to the moisture in your eyes, nose, and throat when exposed to the temperatures the Russians were facing and it's no wonder concern began to mount:
“When you’re outside, it’s extremely cold -- minus 30, minus 40,” microbiologist Dr. David A. Pearce told FoxNews.com. “If you left your eyes open the fluid in them would start to freeze. Your nostrils would start to freeze. The moisture in your mouth would start to freeze,” he said.
Indeed the only thing that doesn't start to freeze is satire: "International Space Station picks up SOS signal from missing 'alien lake' drilling crew."
But while conditions on the ice are indeed life-threatening, Priscu and Pearce never lost faith that the Russians were safe:
DNews: Is the recent lack of contact with the Russians a cause for concern?
Pearce: "No concerns whatsoever."
Priscu: "What they are doing is very, very difficult and has never been done before. I am sure that progress reports are low on their priority list at the moment."
If only Iridium satellite phones could make tweeting status updates easier.
However it seems even contact and updates won't stop the speculation. Have a look again at today's article from RIA Novosti:
With the current events happening at Lake Vostok, an old theory saying that German Nazis may have built a secret base there as early as the 1930s, has resurfaced.
Oh? Indeed, Nazi paranoia is apparently still a very big subject in Moscow. And it's sad that the first report of the scientific break-through of the polar engineers at Lake Vostok, a feat that has been more than 20 years in the making since drilling in the region began in 1989, is steeped in old World War II conspiracy theories from the Russian state-sponsored news agency.
There is much to be concerned about over the techniques and environmental consequences the Russians have taken in using kerosene and other drilling fluids first and a melt drill second in order to reach their goal of breaking the waterline. But these arguments were raised in 1998, two years after the discovery of the lake, and the drilling was suspended for two years in order to better address the situation. Other investigations into subglacial lakes have the foresight now in order to commence drilling using only melt drill technology.
Read more at Discovery News
Feb 5, 2012
Holding Back Immunity
A 'gatekeeper' protein plays a critical role in helping immune cells to sound a warning after encountering signs of tumor growth or infection.
When the body's own cells turn into ticking time bombs, as in cases of viral infection or cancerous transformation, a mechanism known as 'cross-presentation' enables the immune system's dendritic cells (DCs) to sound the alarm.
"Dendritic cells first internalize cancerous or virus-infected cells through a mechanism called phagocytosis, and then process cellular antigens into short peptides," explains Heiichiro Udono of the RIKEN Center for Allergy and Immunology in Yokohama. DCs subsequently present these fragments to killer T cells, which seek out and destroy other affected cells. Phagocytosed molecules travel within sealed membrane bubbles called endosomes, and new work from Udono and his colleagues has revealed insights into how these antigens are released into the cytosol prior to cross-presentation.
Udono's team focused on heat-shock protein 90 (HSP90), a molecule that previous studies have linked to cross-presentation. HSP90 comes in two forms, α and β, which perform overlapping roles. Mice need at least one of these proteins to live. Udono and colleagues succeeded in generating healthy mice that exclusively lack HSP90α. They found that, although HSP90β appears to make some contribution, the loss of HSP90α had a striking effect on antigen processing. DCs isolated from these mice showed defects in their capacity for cross-presentation, and failed to activate killer T cells efficiently following exposure to ovalbumin, a model antigen.
HSP90α-deficient DCs proved perfectly capable of internalizing ovalbumin within endosomes; however, they generally failed to release this antigen into the cytosol. The researchers noted a similar effect after treating genetically normal DCs with a chemical that inhibits HSP90α, confirming the central role of this protein in endosomal release.
Udono and colleagues further demonstrated the extent of these defects by injecting HSP90α-deficient mice with cytochrome c, a protein that selectively eliminates a subpopulation of DCs after being taken up and released into the cytosol. Strikingly, cytochrome c treatment had a dramatically reduced effect on DCs from mutant mice relative to their wild-type counterparts. "This is the most sensitive in vivo assay to show antigen translocation to the cytosol," says Udono. "This phenomenon was absent in HSP90α knockout mice, which makes me confident that our finding is important and has physiological relevance."
Accordingly, Udono believes that molecules that modulate HSP90 activity might help clinicians to boost a patient's immune counterattack against infection or cancer. "If we can control the expression levels of HSP90 and other heat shock proteins," he says, "it could be of great benefit to human health."
Read more at Science Daily
When the body's own cells turn into ticking time bombs, as in cases of viral infection or cancerous transformation, a mechanism known as 'cross-presentation' enables the immune system's dendritic cells (DCs) to sound the alarm.
"Dendritic cells first internalize cancerous or virus-infected cells through a mechanism called phagocytosis, and then process cellular antigens into short peptides," explains Heiichiro Udono of the RIKEN Center for Allergy and Immunology in Yokohama. DCs subsequently present these fragments to killer T cells, which seek out and destroy other affected cells. Phagocytosed molecules travel within sealed membrane bubbles called endosomes, and new work from Udono and his colleagues has revealed insights into how these antigens are released into the cytosol prior to cross-presentation.
Udono's team focused on heat-shock protein 90 (HSP90), a molecule that previous studies have linked to cross-presentation. HSP90 comes in two forms, α and β, which perform overlapping roles. Mice need at least one of these proteins to live. Udono and colleagues succeeded in generating healthy mice that exclusively lack HSP90α. They found that, although HSP90β appears to make some contribution, the loss of HSP90α had a striking effect on antigen processing. DCs isolated from these mice showed defects in their capacity for cross-presentation, and failed to activate killer T cells efficiently following exposure to ovalbumin, a model antigen.
HSP90α-deficient DCs proved perfectly capable of internalizing ovalbumin within endosomes; however, they generally failed to release this antigen into the cytosol. The researchers noted a similar effect after treating genetically normal DCs with a chemical that inhibits HSP90α, confirming the central role of this protein in endosomal release.
Udono and colleagues further demonstrated the extent of these defects by injecting HSP90α-deficient mice with cytochrome c, a protein that selectively eliminates a subpopulation of DCs after being taken up and released into the cytosol. Strikingly, cytochrome c treatment had a dramatically reduced effect on DCs from mutant mice relative to their wild-type counterparts. "This is the most sensitive in vivo assay to show antigen translocation to the cytosol," says Udono. "This phenomenon was absent in HSP90α knockout mice, which makes me confident that our finding is important and has physiological relevance."
Accordingly, Udono believes that molecules that modulate HSP90 activity might help clinicians to boost a patient's immune counterattack against infection or cancer. "If we can control the expression levels of HSP90 and other heat shock proteins," he says, "it could be of great benefit to human health."
Read more at Science Daily
New Study Shows How to Boost the Power of Pain Relief, Without Drugs
Now a new study challenges the theory that the placebo effect is a high-level cognitive function. The authors -- Jason T. Buhle, Bradford L. Stevens, and Jonathan J. Friedman of Columbia University and Tor D. Wager of the University of Colorado Boulder -- reduced pain in two ways -- either by giving them a placebo, or a difficult memory task. lacebo. But when they put the two together, "the level of pain reduction that people experienced added up. There was no interference between them," says Buhle. "That suggests they rely on separate mechanisms." The findings, published in Psychological Science, a journal of the Association for Psychological Science, could help clinicians maximize pain relief without drugs.
In the study, 33 participants came in for three separate sessions. In the first, experimenters applied heat to the skin with a little metal plate and calibrated each individual's pain perceptions. In the second session, some of the people applied an ordinary skin cream they were told was a powerful but safe analgesic. The others put on what they were told was a regular hand cream. In the placebo-only trials, participants stared at a cross on the screen and rated the pain of numerous applications of heat -- the same level, though they were told it varied. For other trials they performed a tough memory task -- distraction and placebo simultaneously. For the third session, those who'd had the plain cream got the "analgesic" and vice versa. The procedure was the same.
The results: With either the memory task or the placebo alone, participants felt less pain than during the trials when they just stared at the cross. Together, the two effects added up; they didn't interact or interfere with each other. The data suggest that the placebo effect does not require executive attention or working memory.
So what about that neuroimaging? "Neuroimaging is great," says Buhle, "but because each brain region does many things, when you see activation in a particular area, you don't know what cognitive process is driving it." This study tested the theory about how placebos work with direct behavioral observation.
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