An enormous prehistoric bird, which might have resembled a very big ostrich, lived alongside dinosaurs around 83 million years ago, according to new research.
The bird, called Samrukia nessovi after the mythical Kazakh Phoenix, lived in what is now Kazakhstan. It is described in the latest Royal Society Biology Letters.
The discovery confirms "that big birds were living alongside Cretaceous non-avian dinosaurs," lead author Darren Naish said. "In fact, these big birds fit into the idea that the Cretaceous wasn't 'a non-avian dinosaurs-only theme park.' Sure, non-avian dinosaurs were important and big in ecological terms, but there was at least some space for other land animals."
Naish is an honorary research associate in the School of Earth & Environmental Sciences at the University of Portsmouth. He and his team made the discovery after analyzing the fossil for Samrukia, which previously had been modified by someone to resemble an oviraptorosaur (a type of feathered dinosaur).
All that's left of this big bird is its toothless lower jaw. The structure and characteristics of the jaw are associated with birds and not non-avian dinosaurs, the researchers believe.
They conclude that the skull of the bird during its lifetime would have been about a foot long. If flightless, it could have stood close to 10 feet tall. If it flew, its wingspan is likely to have exceeded 13 feet.
The big bird is now the second known large avian from the dinosaur era. The first to be identified was Gargantuavis philoinos, which lived in southern France around 70 million years ago. It too may have been flightless and ostrich-like.
"So we can now be really confident that Mesozoic terrestrial birds weren't all thrush-sized or crow-sized animals," Naish said. "Giant size definitely evolved in these animals, and giant forms were living in at least two distinct regions. This fits into a larger, emerging picture: Mesozoic birds were ecologically diverse, with lots of overlap between them and modern groups."
During its day, Samrukia existed in an ecosystem that included armored dinosaurs, duckbilled dinosaurs, and tyrannosaurs -- along with other predatory dinos. Smaller birds are also known from this site, called the Bostobynskaya Formation. Sharks, turtles and salamanders from the bird's time period have also been found in the region.
At present, the site is dry and hot. It's dominated by semi-desert or scrub. Back in the dinosaur era, it was more of a floodplain environment, with a flat plain crisscrossed by big, meandering rivers. Fossil wood suggests forests were nearby.
It remains unclear what the big bird hunted, but the researchers could not find any evidence for obvious specialization, such as dedication to plant consumption or aquatic prey. They therefore suspect it was a generalist, per many modern birds today.
The bird probably also spent a lot of time running or flying away from the numerous meat-eating dinosaurs from the area.
Such distinctions were obviously important to the animals at the time, but paleontologists now must tease apart birds from non-avian dinosaurs. In the case of this latest discovery, a fossil attributed to a dinosaur was determined to be a bird. Recently, however, the supposed "world's oldest known bird," Archaeopteryx, was found to be a non-avian dinosaur. Naish and his team agree with that assessment.
Read more at Discovery News
Aug 10, 2011
Aug 9, 2011
Chimpanzees Not as Selfish as We Thought
Humans aren't the only altruistic primates. New research demonstrates chimpanzees also show unselfish concern for the welfare of others.
The study, published in the latest Proceedings of the National Academy of Sciences, negates prior findings that concluded chimpanzees are "indifferent to the welfare" of their fellow chimps.
Insects and many other creatures help each other out, but it's believed that primate altruism is empathy-based, with this trait being widespread among mammals.
"Since empathy is an old mammalian trait, there is no reason why the sort of altruism we describe should be unique for the primates," co-author Frans de Waal, director of the Living Links Center at the Yerkes Primate Center, told Discovery News.
"I expect it will be found in dogs (and) rats," he added. "We, and others, found it previously in monkeys: capuchin monkeys, marmosets, tamarins."
For this latest study, de Waal and colleagues Victoria Horner, J. Devyn Carter and Malini Suchak presented 7 female chimps with a bucket containing 30 tokens. The scientists chose to look at all females to avoid potential sex-based conflicts.
For each experiment, the tokens came in two different colors. Choosing tokens of a certain color would result in a "selfish outcome," which was a food reward for just the participant. Choosing tokens of the other color resulted in food rewards for both the token selector and another nearby chimp in an adjacent compartment.
The food rewards consisted of banana slices wrapped in butcher paper that made a loud sound when unwrapped.
The chimp participants nearly always chose the tokens that would yield food rewards for both the selector and the nearby observing chimp. They would do this with or without solicitation from the chimp bystander, who could smell the bananas and hear the tantalizing paper unwrapping. At times the bystanders begged, whined and even spit water. Such behavior didn’t help their cause much, contradicting prior suggestions that chimps only share when under social pressure.
The researchers believe earlier studies confused chimp participants, since the experiments involved rather complex apparatuses. These earlier studies, according to lead author Horner and her team, also promoted competition, caused the chimps to become preoccupied with visible reward options, and permitted little communication among the chimps. In this study, “extensive communication” between the participants took place.
Christophe Boesch, director of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology, told Discovery News, "All studies with wild chimpanzees have amply documented that they share meat and other food abundantly, that they help one another in highly risky situations, like when facing predators or neighboring communities, and adopt needing orphans."
Given this information, both he and de Waal expressed frustration over the earlier research that concluded chimpanzees were essentially selfish animals.
More at Discovery News
The study, published in the latest Proceedings of the National Academy of Sciences, negates prior findings that concluded chimpanzees are "indifferent to the welfare" of their fellow chimps.
Insects and many other creatures help each other out, but it's believed that primate altruism is empathy-based, with this trait being widespread among mammals.
"Since empathy is an old mammalian trait, there is no reason why the sort of altruism we describe should be unique for the primates," co-author Frans de Waal, director of the Living Links Center at the Yerkes Primate Center, told Discovery News.
"I expect it will be found in dogs (and) rats," he added. "We, and others, found it previously in monkeys: capuchin monkeys, marmosets, tamarins."
For this latest study, de Waal and colleagues Victoria Horner, J. Devyn Carter and Malini Suchak presented 7 female chimps with a bucket containing 30 tokens. The scientists chose to look at all females to avoid potential sex-based conflicts.
For each experiment, the tokens came in two different colors. Choosing tokens of a certain color would result in a "selfish outcome," which was a food reward for just the participant. Choosing tokens of the other color resulted in food rewards for both the token selector and another nearby chimp in an adjacent compartment.
The food rewards consisted of banana slices wrapped in butcher paper that made a loud sound when unwrapped.
The chimp participants nearly always chose the tokens that would yield food rewards for both the selector and the nearby observing chimp. They would do this with or without solicitation from the chimp bystander, who could smell the bananas and hear the tantalizing paper unwrapping. At times the bystanders begged, whined and even spit water. Such behavior didn’t help their cause much, contradicting prior suggestions that chimps only share when under social pressure.
The researchers believe earlier studies confused chimp participants, since the experiments involved rather complex apparatuses. These earlier studies, according to lead author Horner and her team, also promoted competition, caused the chimps to become preoccupied with visible reward options, and permitted little communication among the chimps. In this study, “extensive communication” between the participants took place.
Christophe Boesch, director of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology, told Discovery News, "All studies with wild chimpanzees have amply documented that they share meat and other food abundantly, that they help one another in highly risky situations, like when facing predators or neighboring communities, and adopt needing orphans."
Given this information, both he and de Waal expressed frustration over the earlier research that concluded chimpanzees were essentially selfish animals.
More at Discovery News
Why Some People Don't Develop Fingerprints
A fingerprint can identify you at birth, death and any time in between. But some people don't develop unique dermal ridges on their fingers, and thus, do not have fingerprints.
In the womb, a fetus begins to form fingerprints after 24 weeks. These patterns, called dermatoglyphs, remain the same throughout most people's lives. But researchers suspect a mutation in one gene allows some people to skip the process of forming fingerprints during development. The rare result: adermatoglyphia, or the condition of not having fingerprints.
After looking at 16 related individuals, scientists reported a mutation in a version of the SMARCAD1 gene region associated with people who lacked fingerprints. They also found adermatoglyphia to be autosomal dominant, meaning only one parent needs to pass on the mutation for the child to show it.
As you can imagine, not having fingerprints can present challenges in countries that regularly use them for identification and travel. In fact, the condition was informally called "immigration delay disease" because of its tendency to limit travel. Interestingly, the team of researchers decided to study one Swiss woman with the condition -- and her family -- after she had issues entering the United States because she had no fingerprints to scan, according to one ScienceNOW article.
Read more at Discovery News
In the womb, a fetus begins to form fingerprints after 24 weeks. These patterns, called dermatoglyphs, remain the same throughout most people's lives. But researchers suspect a mutation in one gene allows some people to skip the process of forming fingerprints during development. The rare result: adermatoglyphia, or the condition of not having fingerprints.
After looking at 16 related individuals, scientists reported a mutation in a version of the SMARCAD1 gene region associated with people who lacked fingerprints. They also found adermatoglyphia to be autosomal dominant, meaning only one parent needs to pass on the mutation for the child to show it.
As you can imagine, not having fingerprints can present challenges in countries that regularly use them for identification and travel. In fact, the condition was informally called "immigration delay disease" because of its tendency to limit travel. Interestingly, the team of researchers decided to study one Swiss woman with the condition -- and her family -- after she had issues entering the United States because she had no fingerprints to scan, according to one ScienceNOW article.
Read more at Discovery News
Mystery Minnesota Monster Sparks Speculation
A strange animal found on a Douglas County, Minnesota, road has people talking monsters.
The Star Tribune offered this description of the animal that Lacey Ilse found alongside a road in Alexandria: “ghostly white and hairless, its neck bloated out of proportion with the rest of its limp body.” Ilse said it looked “half human,” and told her friends about it.
Soon photos of the little beastie flew around the Internet and became a minor Facebook sensation. The Montreal Gazette claimed a few days ago that “scientists are baffled,” though the public has been happy to offer their theories.
Speculations about what the creature may be include a dog, a badger, a wolf, raccoon, and even a top-secret government experiment. Predictably, some suggested that the monster is instead the chupacabra, the Hispanic vampire beast. In fact the animal looks nothing like the original chupacabra (which was revealed earlier this year to have come from a science fiction film), nor does it resemble the “chupacabras” found mainly in Texas that have been shown through DNA analysis to be dogs and coyotes. Furthermore, it was not seen (nor even suspected of) sucking blood.
So what is it?
Biologists have several ways of identifying animals. One of the best is through simply comparing the animal's weight, size, and other characteristics to those of known animals. There’s an even more specialized field of study called taphonomy that deals specifically with dead and decaying animals. Since many animals are found in early states of decomposition, it's important to understand what happens to creatures after they die. For example, hair falls out, tissue shrinks away from teeth and nails, and so on; all these can contribute to a mysterious or otherworldly appearance.
Then, of course, there's genetic analysis. This is considered by many to be the gold standard, though in some cases those who have found mysterious animals have refused to accept the results of DNA testing.
A close analysis of photographs and video of the creature give some important clues to its identity. For one thing, its length and size is well within the normal range for a badger. It has five toes, each ending with long nails. Canine (for example, dog, coyote, or fox) nails are not usually that long, and Minnesota wildlife expert Kevin Kotts said that "It's got five long front claws on each of its front feet, which would be characteristic of a badger.”
Why would it be “ghostly white and hairless”? Because it's been dead a while and the blood has pooled or coagulated, and most of the hair has fallen out from decay. Why would the back part look so misshapen, as several people noticed? Probably because it had been run over by a car or truck, having been found in the middle of the road.
There's another, less obvious reason to believe that the beast is merely a common animal instead of a new creature or unknown monster: only one of them has been found. For the same reason that there must be thousands, or tens of thousands, of Bigfoot in North America to maintain a sufficiently large breeding population, there should be thousands of these critters around if they are a new species.
Read more at Discovery News
The Star Tribune offered this description of the animal that Lacey Ilse found alongside a road in Alexandria: “ghostly white and hairless, its neck bloated out of proportion with the rest of its limp body.” Ilse said it looked “half human,” and told her friends about it.
Soon photos of the little beastie flew around the Internet and became a minor Facebook sensation. The Montreal Gazette claimed a few days ago that “scientists are baffled,” though the public has been happy to offer their theories.
Speculations about what the creature may be include a dog, a badger, a wolf, raccoon, and even a top-secret government experiment. Predictably, some suggested that the monster is instead the chupacabra, the Hispanic vampire beast. In fact the animal looks nothing like the original chupacabra (which was revealed earlier this year to have come from a science fiction film), nor does it resemble the “chupacabras” found mainly in Texas that have been shown through DNA analysis to be dogs and coyotes. Furthermore, it was not seen (nor even suspected of) sucking blood.
So what is it?
Biologists have several ways of identifying animals. One of the best is through simply comparing the animal's weight, size, and other characteristics to those of known animals. There’s an even more specialized field of study called taphonomy that deals specifically with dead and decaying animals. Since many animals are found in early states of decomposition, it's important to understand what happens to creatures after they die. For example, hair falls out, tissue shrinks away from teeth and nails, and so on; all these can contribute to a mysterious or otherworldly appearance.
Then, of course, there's genetic analysis. This is considered by many to be the gold standard, though in some cases those who have found mysterious animals have refused to accept the results of DNA testing.
A close analysis of photographs and video of the creature give some important clues to its identity. For one thing, its length and size is well within the normal range for a badger. It has five toes, each ending with long nails. Canine (for example, dog, coyote, or fox) nails are not usually that long, and Minnesota wildlife expert Kevin Kotts said that "It's got five long front claws on each of its front feet, which would be characteristic of a badger.”
Why would it be “ghostly white and hairless”? Because it's been dead a while and the blood has pooled or coagulated, and most of the hair has fallen out from decay. Why would the back part look so misshapen, as several people noticed? Probably because it had been run over by a car or truck, having been found in the middle of the road.
There's another, less obvious reason to believe that the beast is merely a common animal instead of a new creature or unknown monster: only one of them has been found. For the same reason that there must be thousands, or tens of thousands, of Bigfoot in North America to maintain a sufficiently large breeding population, there should be thousands of these critters around if they are a new species.
Read more at Discovery News
Meteorites Carried Life's Building Block to Earth
A new analysis of carbon meteorites suggests that they likely carried some of the building blocks needed for DNA to the Earth, according to a NASA-funded study.
The research in the Proceedings of the National Academy of Sciences adds weight to the long-debated theory that at least some of the materials needed to make early life forms came to our planet via meteorites.
Scientists used advanced mass spectrometry instruments to scan 11 organic-rich meteorites called carbonaceous chondrites for nucleobases, which contribute to making DNA and RNA.
They found three nucleobases -- purine, 6,8-diaminopurine and 2,6-diaminopurine -- that "are widely distributed in carbonaceous chondrites" and which are "rare or absent in terrestrial biology," said the study.
Scientists found no significant concentrations of the trio in soil and ice samples near where the meteorites landed, the study said.
"Finding nucleobase compounds not typically found in Earth's biochemistry strongly supports an extraterrestrial origin," said Jim Cleaves, one of the study's authors from the Carnegie Institute of Washington's Geophysical Laboratory.
"This shows us that meteorites may have been molecular tool kits, which provided the essential building blocks for life on Earth," Cleaves said.
More at Discovery News
The research in the Proceedings of the National Academy of Sciences adds weight to the long-debated theory that at least some of the materials needed to make early life forms came to our planet via meteorites.
Scientists used advanced mass spectrometry instruments to scan 11 organic-rich meteorites called carbonaceous chondrites for nucleobases, which contribute to making DNA and RNA.
They found three nucleobases -- purine, 6,8-diaminopurine and 2,6-diaminopurine -- that "are widely distributed in carbonaceous chondrites" and which are "rare or absent in terrestrial biology," said the study.
Scientists found no significant concentrations of the trio in soil and ice samples near where the meteorites landed, the study said.
"Finding nucleobase compounds not typically found in Earth's biochemistry strongly supports an extraterrestrial origin," said Jim Cleaves, one of the study's authors from the Carnegie Institute of Washington's Geophysical Laboratory.
"This shows us that meteorites may have been molecular tool kits, which provided the essential building blocks for life on Earth," Cleaves said.
More at Discovery News
Aug 8, 2011
Did Past Climate Change Encourage Tree-Killing Fungi?
The demise of the world's forests some 250 million years ago likely was accelerated by aggressive tree-killing fungi triggered by global climate change, according to a new study by a University of California, Berkeley, scientist and her Dutch and British colleagues.
The researchers do not rule out the possibility that today's changing climate could cause a similar increase in pathogenic soil bacteria that could devastate forests already stressed by a warming climate and pollution.
The study, available online Aug. 5, will be published in the September 2011 print edition of the journal Geology of the Geological Society of America.
The death of the forests -- primarily composed of conifers, which are distant relatives of today's pines and firs -- was part of the largest extinction of life on Earth, which occurred when today's continents were part of one supercontinent, Pangaea. The so-called Permian extinction likely was triggered by immense volcanic eruptions in what is now Siberia. The huge amounts of gas and dust thrown into the atmosphere altered global climate, and some 95 percent of marine organisms and 70 percent of land organisms eventually went extinct.
The scientists claim that thread-like or filamentous microfossils commonly preserved in Permian rock are relatives of a group of fungi, Rhizoctonia, that today is known for members that attack and kill plants.
"Modern Rhizoctonia include some of the most ubiquitous plant pathogens, causing root, stem and foliar diseases in a wide variety of plants," said coauthor Cindy Looy, UC Berkeley assistant professor of integrative biology. "Based on patterns of present-day forest decline, it is likely that fungal disease has been an essential accessory in woodland destabilization, accelerating widespread tree mortality during the end-Permian crisis."
The conifer forests, which covered the semi-arid equatorial region of Pangaea, were eventually replaced by lycopods -- four foot-tall relatives of today's diminutive club mosses -- as well as by seed ferns (pteridosperms). The conifers didn't recover for another 4 to 5 million years.
Looy and her colleagues -- Henk Visscher of the Laboratory of Palaeobotany and Palynology at Utrecht University in the Netherlands and Mark Sephton of the Impacts and Astromaterials Research Centre at Imperial College, London -- caution that today's changing climate could also lead to increased activity of pathogenic soil microbes that could accelerate the death of trees already stressed by higher temperatures and drought.
"Pathogenic fungi are important elements of all forest ecosystems," said Visscher. "When an entire forest becomes weakened by environmental stress factors, onslaught of damaging fungal diseases can result in large-scale tissue death and tree mortality."
The researchers dispute the conclusion of other researchers who claim that the thread-like microfossils are the remains of algae. Furthermore, while the researchers previously thought that Reduviasporonites were fungi that took advantage of dying forests, they now believe the fungi actively helped destroy the forests.
"Previously, mass occurrences of Reduviasporonites had been ascribed to wood-rotting fungi living off an excessive abundance of dead wood," said Looy, a paleobotanist who focuses on pollen and spores as keys to understanding past plant communities. "However, the notion that the microfossils represent Rhizoctonia-like resting structures suggest a much more active role for fungi in the ecological crisis:"
The researchers' conclusion comes largely from the fact that they have found living fungi in the genus Rhizoctonia that have a dormant or resting stage during their life cycles in which they look nearly identical to Reduviasporonites.
Read more at Science Daily
The researchers do not rule out the possibility that today's changing climate could cause a similar increase in pathogenic soil bacteria that could devastate forests already stressed by a warming climate and pollution.
The study, available online Aug. 5, will be published in the September 2011 print edition of the journal Geology of the Geological Society of America.
The death of the forests -- primarily composed of conifers, which are distant relatives of today's pines and firs -- was part of the largest extinction of life on Earth, which occurred when today's continents were part of one supercontinent, Pangaea. The so-called Permian extinction likely was triggered by immense volcanic eruptions in what is now Siberia. The huge amounts of gas and dust thrown into the atmosphere altered global climate, and some 95 percent of marine organisms and 70 percent of land organisms eventually went extinct.
The scientists claim that thread-like or filamentous microfossils commonly preserved in Permian rock are relatives of a group of fungi, Rhizoctonia, that today is known for members that attack and kill plants.
"Modern Rhizoctonia include some of the most ubiquitous plant pathogens, causing root, stem and foliar diseases in a wide variety of plants," said coauthor Cindy Looy, UC Berkeley assistant professor of integrative biology. "Based on patterns of present-day forest decline, it is likely that fungal disease has been an essential accessory in woodland destabilization, accelerating widespread tree mortality during the end-Permian crisis."
The conifer forests, which covered the semi-arid equatorial region of Pangaea, were eventually replaced by lycopods -- four foot-tall relatives of today's diminutive club mosses -- as well as by seed ferns (pteridosperms). The conifers didn't recover for another 4 to 5 million years.
Looy and her colleagues -- Henk Visscher of the Laboratory of Palaeobotany and Palynology at Utrecht University in the Netherlands and Mark Sephton of the Impacts and Astromaterials Research Centre at Imperial College, London -- caution that today's changing climate could also lead to increased activity of pathogenic soil microbes that could accelerate the death of trees already stressed by higher temperatures and drought.
"Pathogenic fungi are important elements of all forest ecosystems," said Visscher. "When an entire forest becomes weakened by environmental stress factors, onslaught of damaging fungal diseases can result in large-scale tissue death and tree mortality."
The researchers dispute the conclusion of other researchers who claim that the thread-like microfossils are the remains of algae. Furthermore, while the researchers previously thought that Reduviasporonites were fungi that took advantage of dying forests, they now believe the fungi actively helped destroy the forests.
"Previously, mass occurrences of Reduviasporonites had been ascribed to wood-rotting fungi living off an excessive abundance of dead wood," said Looy, a paleobotanist who focuses on pollen and spores as keys to understanding past plant communities. "However, the notion that the microfossils represent Rhizoctonia-like resting structures suggest a much more active role for fungi in the ecological crisis:"
The researchers' conclusion comes largely from the fact that they have found living fungi in the genus Rhizoctonia that have a dormant or resting stage during their life cycles in which they look nearly identical to Reduviasporonites.
Read more at Science Daily
Brain's Map of Space Falls Flat When It Comes to Altitude
Animal's brains are only roughly aware of how high-up they are in space, meaning that in terms of altitude the brain's 'map' of space is surprisingly flat, according to new research.
In a study published online August 7 in Nature Neuroscience, scientists studied cells in or near a part of the brain called the hippocampus, which forms the brain's map of space, to see whether they were activated when rats climbed upwards.
The study, supported by the Wellcome Trust, looked at two types of cells known to be involved in the brain's representation of space: grid cells, which measure distance, and place cells, which indicate location. Scientists found that only place cells were sensitive to the animal moving upwards in altitude, and even then only weakly so.
Professor Kate Jeffery, lead author from UCL Psychology and Language Sciences, said: "The implication is that our internal sense of space is actually rather flat -- we are very sensitive to where we are in horizontal space but only vaguely aware of how high we are.
"This finding is surprising and it has implications for situations in which people have to move freely in all three dimensions -- divers, pilots and astronauts for example. It also raises the question -- if our map of space is flat, then how do we navigate through complex environments so effectively?"
How the hippocampus makes its map of space is fairly well understood for flat environments, but the world is of course not flat -- it has a richly varied topography, and a useful map therefore needs to work in all three dimensions. However, adding a third dimension to the two horizontal ones makes things very much more complicated for a map, and it is not clear how -- or even if -- the brain can encode this.
To begin to answer this question scientists looked at neurons known as grid cells, which become active periodically and at very regular distances as animals walk around, forming a grid-like structure of activity hot-spots. Previous work has found that grid cells are largely concerned with marking out distances.
In the study, rats walked not just on flat ground but also on pegs on a climbing wall, or else on a spiral staircase, so that the rats moved not only horizontally but also vertically. Interestingly, the grid cells still kept track of horizontal distance but did not measure out vertical distances. It seems as if grid cells do not "know" how high they are.
More at Science Daily
In a study published online August 7 in Nature Neuroscience, scientists studied cells in or near a part of the brain called the hippocampus, which forms the brain's map of space, to see whether they were activated when rats climbed upwards.
The study, supported by the Wellcome Trust, looked at two types of cells known to be involved in the brain's representation of space: grid cells, which measure distance, and place cells, which indicate location. Scientists found that only place cells were sensitive to the animal moving upwards in altitude, and even then only weakly so.
Professor Kate Jeffery, lead author from UCL Psychology and Language Sciences, said: "The implication is that our internal sense of space is actually rather flat -- we are very sensitive to where we are in horizontal space but only vaguely aware of how high we are.
"This finding is surprising and it has implications for situations in which people have to move freely in all three dimensions -- divers, pilots and astronauts for example. It also raises the question -- if our map of space is flat, then how do we navigate through complex environments so effectively?"
How the hippocampus makes its map of space is fairly well understood for flat environments, but the world is of course not flat -- it has a richly varied topography, and a useful map therefore needs to work in all three dimensions. However, adding a third dimension to the two horizontal ones makes things very much more complicated for a map, and it is not clear how -- or even if -- the brain can encode this.
To begin to answer this question scientists looked at neurons known as grid cells, which become active periodically and at very regular distances as animals walk around, forming a grid-like structure of activity hot-spots. Previous work has found that grid cells are largely concerned with marking out distances.
In the study, rats walked not just on flat ground but also on pegs on a climbing wall, or else on a spiral staircase, so that the rats moved not only horizontally but also vertically. Interestingly, the grid cells still kept track of horizontal distance but did not measure out vertical distances. It seems as if grid cells do not "know" how high they are.
More at Science Daily
Earth May Not Have Needed Moon for Life
Scientists have long believed that without the moon's stabilizing gravitational influence, variations in Earth's tilt would have caused climate change too dynamic for complex life to evolve. Not so, concludes a new study that has implications for understanding conditions for life elsewhere in the solar system.
The study sprang from the ongoing Kepler Telescope mission to find Earth-like planets circling in habitable zones around other stars in the Milky Way.
"We were wondering 'Do we really have to find a moon or not?' around potentially habitable worlds, planetary scientist Jason Barnes, with the University of Idaho, told Discovery News.
Previous studies showed that without the steadying gravitational influence of a large moon, Earth's tilt would shift by as much as about 85 degrees every 100,000 years or so, alternatively freezing and baking the planet's poles. Scientists believe a stable climate spanning about 500,000 years was necessary for complex life to blossom on Earth.
A new computational analysis, however, shows that a moonless Earth would still have swings in its tilt but the influence of Jupiter and other factors would limit the variations to about 10 degrees in either direction.
Earth's rotational tilt varies between 0.5 and 1 degree about every 100,000 years.
"Plus- or minus-10 would certainly be noticeable and may be a problem, but I don't think it would prevent life from coming about," Barnes said.
"It's a very intriguing result. It's provocative," Richard Vondrak, lead scientist with NASA's ongoing Lunar Reconnaissance Orbiter mission, told Discovery News.
"On the moon we can find important evidence and clues of what happened to not only to the moon, but also to the Earth-moon system over the last 4.5 billion years," said Vondrak, a planetary scientist with NASA's Goddard Space Flight Center in Greenbelt, Md.
The study also showed that if Earth revolved around the sun in the opposite direction, called a retrograde orbit, it wouldn't need a moon at all to have a climate about as stable as it has today. Likewise, a Jupiter about half the distance to Earth as its present location would have had a similar steading hand, Barnes added.
The findings are causing extrasolar planet hunters to revise their thinking on what constitutes a habitable planet.
"We think that at least 80 or 90 percent of planets out there statistically won't even require a moon" to have a stable climate, Barnes said.
Location is key. In our own solar system, Mars shows evidence of extreme climate change, the result, scientists believe, of a rotational tilt that flips between zero and 60 degrees over time. A big moon likely could have helped stabilize Mars' orbit, but the planet has just two small moons, most likely captured asteroids, that don't have much gravitational muscle.
Read more at Discovery News
The study sprang from the ongoing Kepler Telescope mission to find Earth-like planets circling in habitable zones around other stars in the Milky Way.
"We were wondering 'Do we really have to find a moon or not?' around potentially habitable worlds, planetary scientist Jason Barnes, with the University of Idaho, told Discovery News.
Previous studies showed that without the steadying gravitational influence of a large moon, Earth's tilt would shift by as much as about 85 degrees every 100,000 years or so, alternatively freezing and baking the planet's poles. Scientists believe a stable climate spanning about 500,000 years was necessary for complex life to blossom on Earth.
A new computational analysis, however, shows that a moonless Earth would still have swings in its tilt but the influence of Jupiter and other factors would limit the variations to about 10 degrees in either direction.
Earth's rotational tilt varies between 0.5 and 1 degree about every 100,000 years.
"Plus- or minus-10 would certainly be noticeable and may be a problem, but I don't think it would prevent life from coming about," Barnes said.
"It's a very intriguing result. It's provocative," Richard Vondrak, lead scientist with NASA's ongoing Lunar Reconnaissance Orbiter mission, told Discovery News.
"On the moon we can find important evidence and clues of what happened to not only to the moon, but also to the Earth-moon system over the last 4.5 billion years," said Vondrak, a planetary scientist with NASA's Goddard Space Flight Center in Greenbelt, Md.
The study also showed that if Earth revolved around the sun in the opposite direction, called a retrograde orbit, it wouldn't need a moon at all to have a climate about as stable as it has today. Likewise, a Jupiter about half the distance to Earth as its present location would have had a similar steading hand, Barnes added.
The findings are causing extrasolar planet hunters to revise their thinking on what constitutes a habitable planet.
"We think that at least 80 or 90 percent of planets out there statistically won't even require a moon" to have a stable climate, Barnes said.
Location is key. In our own solar system, Mars shows evidence of extreme climate change, the result, scientists believe, of a rotational tilt that flips between zero and 60 degrees over time. A big moon likely could have helped stabilize Mars' orbit, but the planet has just two small moons, most likely captured asteroids, that don't have much gravitational muscle.
Read more at Discovery News
Aug 7, 2011
Potential New Eye Tumor Treatment Discovered
New research from a team including several Carnegie scientists demonstrates that a specific small segment of RNA could play a key role in the growth of a type of malignant childhood eye tumor called retinoblastoma. The tumor is associated with mutations of a protein called Rb, or retinoblastoma protein. Dysfunctional Rb is also involved with other types of cancers, including lung, brain, breast and bone.
Their work, which will be the cover story of the August 15th issue of Genes & Development, could result in a new therapeutic target for treating this rare form of cancer and potentially other cancers as well.
MicroRNAs are a short, single strands of genetic material that bind to longer strands of messenger RNA--which is the courier that brings the genetic code from the DNA in the nucleus to the cell's ribosome, where it is translated into protein. This binding activity allows microRNAs to silence the expression of select genes in a targeted manner. Abnormal versions of microRNAs have been implicated in the growth of several types of cancer.
The paper from Carnegie's Karina Conkrite, Maggie Sundby and David MacPherson--as well as authors from other institutions -- focuses on a cluster of microRNAs called miR-17~92. Recent research has shown that aberrant versions of this cluster are involved in preventing pre-cancerous cells from dying and allowing them to proliferate into tumors. Previous work has shown that miR-17~92 can be involved in the survival of lymphoma and leukemia cells by reducing the levels of a tumor-suppressing protein called PTEN.
The team's new research shows that miR-17~92 can also be involved in retinoblastoma, although it does not act in the same way, via the PTEN protein, as it does in other types of cancers. Rather, miR-17~92 acts to help cells that lack the tumor-suppressing Rb protein to proliferate.
First the team demonstrated that miR-17~92 is expressed in higher-than-usual quantities in all human retinoblastomas examined and in some mouse retinoblastomas. The authors engineered mice to express high levels of miR-17~92 in their retinas. When coupled with inactivation of Rb family members, expression of miR-17~92 led to extremely rapid and aggressive retinoblastoma. Then they showed that this abundance of miR-17~92 acts to suppress an inhibitor of proliferation, called p21Cip1, which is supposed to compensate for the loss of Rb.
More at Science Daily
Their work, which will be the cover story of the August 15th issue of Genes & Development, could result in a new therapeutic target for treating this rare form of cancer and potentially other cancers as well.
MicroRNAs are a short, single strands of genetic material that bind to longer strands of messenger RNA--which is the courier that brings the genetic code from the DNA in the nucleus to the cell's ribosome, where it is translated into protein. This binding activity allows microRNAs to silence the expression of select genes in a targeted manner. Abnormal versions of microRNAs have been implicated in the growth of several types of cancer.
The paper from Carnegie's Karina Conkrite, Maggie Sundby and David MacPherson--as well as authors from other institutions -- focuses on a cluster of microRNAs called miR-17~92. Recent research has shown that aberrant versions of this cluster are involved in preventing pre-cancerous cells from dying and allowing them to proliferate into tumors. Previous work has shown that miR-17~92 can be involved in the survival of lymphoma and leukemia cells by reducing the levels of a tumor-suppressing protein called PTEN.
The team's new research shows that miR-17~92 can also be involved in retinoblastoma, although it does not act in the same way, via the PTEN protein, as it does in other types of cancers. Rather, miR-17~92 acts to help cells that lack the tumor-suppressing Rb protein to proliferate.
First the team demonstrated that miR-17~92 is expressed in higher-than-usual quantities in all human retinoblastomas examined and in some mouse retinoblastomas. The authors engineered mice to express high levels of miR-17~92 in their retinas. When coupled with inactivation of Rb family members, expression of miR-17~92 led to extremely rapid and aggressive retinoblastoma. Then they showed that this abundance of miR-17~92 acts to suppress an inhibitor of proliferation, called p21Cip1, which is supposed to compensate for the loss of Rb.
More at Science Daily
Captain Morgan's Pirate Ship Found
The lost wreckage of a ship belonging to 17th century pirate Captain Henry Morgan has been discovered in Panama, said a team of U.S. archaeologists -- and the maker of Captain Morgan rum.
Near the Lajas Reef, where Morgan lost five ships in 1671 including his flagship "Satisfaction," the team uncovered a portion of the starboard side of a wooden ship's hull and a series of unopened cargo boxes and chests encrusted in coral.
The cargo has yet to be opened, but Captain Morgan USA -- which sells the spiced rum named for the eponymous pirate -- is clearly hoping there's liquor in there.
"There's definitely an irony in the situation," Fritz Hanselmann an archaeologist with the River Systems Institute and the Center for Archaeological Studies at Texas State University and head of the dive team told KVUE Austin. The Captain Morgan rum group stepped in on the quest for Captain Morgan after team -- which found a collection of iron cannons nearby -- ran out of funds before they could narrow down the quest.
The new funding allowed the team to do a magnetometer survey, which looks for metal by finding any deviation in the earth's magnetic field.
"When the opportunity arose for us to help make this discovery mission possible, it was a natural fit for us to get involved. The artifacts uncovered during this mission will help bring Henry Morgan and his adventures to life in a way never thought possible," said Tom Herbst, brand director of Captain Morgan USA, in a statement.
In the 17th century, Captain Henry Morgan sailed as a privateer on behalf of England, defending the Crown's interests and pioneering expeditions to the New World. In 1671, in an effort to capture Panama City and loosen the stronghold of Spain in the Caribbean, Morgan set out to take the Castillo de San Lorenzo, a Spanish fort on the cliff overlooking the entrance to the Chagres River, the only water passageway between the Caribbean and the capital city.
Read more at Discovery News
Near the Lajas Reef, where Morgan lost five ships in 1671 including his flagship "Satisfaction," the team uncovered a portion of the starboard side of a wooden ship's hull and a series of unopened cargo boxes and chests encrusted in coral.
The cargo has yet to be opened, but Captain Morgan USA -- which sells the spiced rum named for the eponymous pirate -- is clearly hoping there's liquor in there.
"There's definitely an irony in the situation," Fritz Hanselmann an archaeologist with the River Systems Institute and the Center for Archaeological Studies at Texas State University and head of the dive team told KVUE Austin. The Captain Morgan rum group stepped in on the quest for Captain Morgan after team -- which found a collection of iron cannons nearby -- ran out of funds before they could narrow down the quest.
The new funding allowed the team to do a magnetometer survey, which looks for metal by finding any deviation in the earth's magnetic field.
"When the opportunity arose for us to help make this discovery mission possible, it was a natural fit for us to get involved. The artifacts uncovered during this mission will help bring Henry Morgan and his adventures to life in a way never thought possible," said Tom Herbst, brand director of Captain Morgan USA, in a statement.
In the 17th century, Captain Henry Morgan sailed as a privateer on behalf of England, defending the Crown's interests and pioneering expeditions to the New World. In 1671, in an effort to capture Panama City and loosen the stronghold of Spain in the Caribbean, Morgan set out to take the Castillo de San Lorenzo, a Spanish fort on the cliff overlooking the entrance to the Chagres River, the only water passageway between the Caribbean and the capital city.
Read more at Discovery News
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