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| ©Uranus image courtesy NASA/Space Telescope Science Institute; Neptune image courtesy NASA/JPL |
| The gas giant planets of our solar system took shape twice as close to the sun as they are now and slowly moved outward, according to a new theory that challenges established ideas for how the gas giants formed. But for this theory to work, the lead author says, Uranus (left) and Neptune (right) had to have switched orbital positions up to four billion years ago. |
Science & Technology
Like children growing up and moving away from home, the gas giant planets of our solar system took shape twice as close to the sun as they are now and slowly moved outward.
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| INCINERATION POSSIBLE - Fine points of the "fireball" that might be expected from an asteroid exploding in Earth's atmosphere are indicated in a supercomputer simulation devised by a team led by Sandia researcher Mark Boslough. (Photo by Randy Montoya) |
The stunning amount of forest devastation at Tunguska a century ago in Siberia may have been caused by an asteroid only a fraction as large as previously published estimates, Sandia National Laboratories supercomputer simulations suggest.
"The asteroid that caused the extensive damage was much smaller than we had thought," says Sandia principal investigator Mark Boslough of the impact that occurred June 30, 1908. "That such a small object can do this kind of destruction suggests that smaller asteroids are something to consider. Their smaller size indicates such collisions are not as improbable as we had believed."
The human brain constantly sorts through its 1 trillion cells, looking for perhaps only one or a handful of neurons to carry out a particular action, a trio of new studies says.
The research, conducted with rodents and published in the Dec. 20 issue of Nature, could rewrite the textbooks on just how important individual brain cells or cell clusters are to the working mind.
Before these insights, "The thinking was that very large ensembles of neurons [brain cells] had to be activated at some point for the animal to feel or perceive" a stimulus, explained the senior researcher of two of the studies, Karel Svoboda, a group leader at the Howard Hughes Medical Institute in Ashburn, Va.
The research, conducted with rodents and published in the Dec. 20 issue of Nature, could rewrite the textbooks on just how important individual brain cells or cell clusters are to the working mind.
Before these insights, "The thinking was that very large ensembles of neurons [brain cells] had to be activated at some point for the animal to feel or perceive" a stimulus, explained the senior researcher of two of the studies, Karel Svoboda, a group leader at the Howard Hughes Medical Institute in Ashburn, Va.
Some seals and dolphins can hold their breath underwater for a cheek-popping hour or more without passing out from lack of oxygen.
Definitely don't try this at home. Humans can't make it more than a few minutes without breathing (at least without some sci-fi device).
The secret to the superhero animal feat is elevated levels of special oxygen-carrying proteins found in their brains, a new study reveals. But the research leaves puzzles.
Scientists have long wondered why marine mammals, such as dolphins, whales, Weddell seals and sea otters, are so tolerant of such low oxygen conditions. The simplest explanation had been that they evolved adaptations to boost oxygen delivery to the brain. But studies have shown that the oxygen levels in their blood vessels plummeted within minutes of dipping beneath the water's surface.
Definitely don't try this at home. Humans can't make it more than a few minutes without breathing (at least without some sci-fi device).
The secret to the superhero animal feat is elevated levels of special oxygen-carrying proteins found in their brains, a new study reveals. But the research leaves puzzles.
Scientists have long wondered why marine mammals, such as dolphins, whales, Weddell seals and sea otters, are so tolerant of such low oxygen conditions. The simplest explanation had been that they evolved adaptations to boost oxygen delivery to the brain. But studies have shown that the oxygen levels in their blood vessels plummeted within minutes of dipping beneath the water's surface.
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| ©T. M. Williams/UCSC |
| Beau Richter monitors the breath-holding cabability of Puka, a bottlenose dolphin at UC Santa Cruz's Long Marine Laboratory. Researchers found some marine mammals may be able to endure low oxygen levels due to enhanced amounts of proteins called globins in their brains. |
Bridges built from bamboo instead of steel could provide a cheaper, more environmentally sustainable engineering solution in China, a recent experiment suggests.
A novel type of bridge with horizontal beams made from a bamboo composite proved strong enough to support even heavy trucks in tests. The bamboo beams are cheaper and more environmentally friendly to make than steel or concrete, yet offer comparable structural strength.
Yan Xiao, who works at the University of Southern California, in Los Angeles, US, and at Hunan University in China, led the development of the bamboo beams used to make the bridge.
Instead of using round, pole-like pieces of unprocessed bamboo, which have been used as building material for many thousands of years, he came up with a way of assembling timber-like beams from many smaller strips of bamboo.
A novel type of bridge with horizontal beams made from a bamboo composite proved strong enough to support even heavy trucks in tests. The bamboo beams are cheaper and more environmentally friendly to make than steel or concrete, yet offer comparable structural strength.
Yan Xiao, who works at the University of Southern California, in Los Angeles, US, and at Hunan University in China, led the development of the bamboo beams used to make the bridge.
Instead of using round, pole-like pieces of unprocessed bamboo, which have been used as building material for many thousands of years, he came up with a way of assembling timber-like beams from many smaller strips of bamboo.
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| ©University of Southern California |
| The novel bridge with horizontal beams made from a bamboo composite proved strong enough to support even heavy trucks |
A racoon-sized mammal which lived in India about 48 million years ago, may represent one of the missing links in whale evolution, suggests a new fossil study.
The research also challenges the idea that cetaceans - the order that includes whales, dolphins, and porpoises - split from their land-dwelling forebears and returned to the water to hunt aquatic prey.
Researchers studying 48-million-year-old fossils of Indohyus, an extinct animal which may have looked like a small deer, from ancient riverbeds in Kashmir suggest that the fossils represent a likely ancestor of the cetaceans.
Indohyus belongs to a family known as raoellids and would have lived around the same time as early cetaceans, both having descended from a common ancestor, they suggest.
The research also challenges the idea that cetaceans - the order that includes whales, dolphins, and porpoises - split from their land-dwelling forebears and returned to the water to hunt aquatic prey.
Researchers studying 48-million-year-old fossils of Indohyus, an extinct animal which may have looked like a small deer, from ancient riverbeds in Kashmir suggest that the fossils represent a likely ancestor of the cetaceans.
Indohyus belongs to a family known as raoellids and would have lived around the same time as early cetaceans, both having descended from a common ancestor, they suggest.
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| ©Carl Buell |
| Evidence shows that Indohyus was at least in part an eater of vegetation and did not return to a watery life to hunt |
It's a good thing the Moon doesn't have any feelings to hurt. New research suggests it is actually 30 million years younger than anyone had thought, and that it is merely a 'chip off the old block' of Earth rather than being made up of the remnants of a Mars-sized body that slammed into Earth billions of years ago.
That violent impact was thought to have taken place 30 million years after the solar system began to condense from a disc of gas and dust 4.567 billion years ago. The event was thought to have melted the Earth, generating a magma ocean that covered the planet and allowed iron and other metals to sink to its centre, forming a core.
At the same time, the Moon was thought to have coalesced from a disc of molten debris blasted off the Earth and the Mars-sized interloper.
But new research led by Mathieu Touboul of the Swiss Federal Institute of Technology in Zurich suggests that picture is not so simple. The researchers base their analysis on studies of an isotope of the metal tungsten in lunar rocks.
That violent impact was thought to have taken place 30 million years after the solar system began to condense from a disc of gas and dust 4.567 billion years ago. The event was thought to have melted the Earth, generating a magma ocean that covered the planet and allowed iron and other metals to sink to its centre, forming a core.
At the same time, the Moon was thought to have coalesced from a disc of molten debris blasted off the Earth and the Mars-sized interloper.
But new research led by Mathieu Touboul of the Swiss Federal Institute of Technology in Zurich suggests that picture is not so simple. The researchers base their analysis on studies of an isotope of the metal tungsten in lunar rocks.
Vacuum cleaners kill fleas just as well as any poison, surprised U.S. researchers said on Tuesday.
They said a standard vacuum cleaner abuses the fleas so much it kills 96 percent of adult fleas and 100 percent of younger fleas.
So no need to worry that a vacuum cleaner bag may turn into a fleabag breeding ground for the pesky, biting creatures, said Glen Needham, associate professor of entomology at Ohio State University.
Needham studied the cat flea, or Ctenocephalides felis, the most common type of flea found in households.
They said a standard vacuum cleaner abuses the fleas so much it kills 96 percent of adult fleas and 100 percent of younger fleas.
So no need to worry that a vacuum cleaner bag may turn into a fleabag breeding ground for the pesky, biting creatures, said Glen Needham, associate professor of entomology at Ohio State University.
Needham studied the cat flea, or Ctenocephalides felis, the most common type of flea found in households.
Carnivorous Argentine ants that have invaded coastal California devour other insects. When that food's gone, the ants become vegetarians.
The amazingly adaptive behavior, detailed in what is the first study of this ant's diet, has allowed the invaders to spread successfully and rapidly.
The tiny dark-brown and black critters, an invasive species originally from Argentina, have infested coastal communities and displaced native ant species, even though many of the locals are 10 times larger than the Argentinians.
The new finding, based on an eight-year study of a population of ants in the foothills southeast of San Diego, reveals how the alien ants thrive so well in a foreign land. Their success is linked to their dietary versatility, according to results detailed in this week's online issue of the journal Proceedings of the National Academy of Sciences.
The amazingly adaptive behavior, detailed in what is the first study of this ant's diet, has allowed the invaders to spread successfully and rapidly.
The tiny dark-brown and black critters, an invasive species originally from Argentina, have infested coastal communities and displaced native ant species, even though many of the locals are 10 times larger than the Argentinians.
The new finding, based on an eight-year study of a population of ants in the foothills southeast of San Diego, reveals how the alien ants thrive so well in a foreign land. Their success is linked to their dietary versatility, according to results detailed in this week's online issue of the journal Proceedings of the National Academy of Sciences.
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| ©Credit: Marc Dantzker |
| Argentine ants fighting. These ants are thought to have come to the United States from Argentina aboard ships in the 1890s. |
Monkeys can perform mental addition in a manner remarkably similar to college students, a new study shows.
The researchers stressed that monkeys will not pass college math tests anytime soon. Nevertheless, the finding promises to shed light on the ancient origins of math in humanity and our distant relatives.
Humans possess a sophisticated repertoire of mathematical capabilities unmatched anywhere else in the animal kingdom. Still, there is increasing evidence that at least some of these abilities are shared with other animals. For instance, many animals can figure out which of two sets of dots is larger or smaller.
The researchers stressed that monkeys will not pass college math tests anytime soon. Nevertheless, the finding promises to shed light on the ancient origins of math in humanity and our distant relatives.
Humans possess a sophisticated repertoire of mathematical capabilities unmatched anywhere else in the animal kingdom. Still, there is increasing evidence that at least some of these abilities are shared with other animals. For instance, many animals can figure out which of two sets of dots is larger or smaller.
