Headline of the day
McEnroe fears mafia infiltrating tennis...(The Drudge Report)
Why is he surprised? It’s a game where they use a racket.
We’ve already told you, it’s in the sock drawer
Supercomputer Simulation Of Universe May Help In Search For Missing Matter
ScienceDaily (Dec. 7, 2007) — Much of the gaseous mass of the universe is bound up in a tangled web of cosmic filaments that stretch for hundreds of millions of light-years, according to a new supercomputer study by a team led by the University of Colorado at
The study indicated a significant portion of the gas is in the filaments -- which connect galaxy clusters -- hidden from direct observation in enormous gas clouds in intergalactic space known as the Warm-Hot Intergalactic Medium, or WHIM, said CU-Boulder Professor Jack Burns of the astrophysical and planetary sciences department. The team performed one of the largest cosmological supercomputer simulations ever, cramming 2.5 percent of the visible universe inside a computer to model a region more than 1.5 billion light-years across. One light-year is equal to about six trillion miles.
It took the researchers nearly a decade to produce the extraordinarily complex computer code that drove the simulation, which incorporated virtually all of the known physical conditions of the universe reaching back in time almost to the Big Bang, said Burns. The simulation -- which uses advanced numerical techniques to zoom-in on interesting structures in the universe -- modeled the motion of matter as it collapsed due to gravity and became dense enough to form cosmic filaments and galaxy structures.
"We see this as a real breakthrough in terms of technology and in scientific advancement," said Burns. "We believe this effort brings us a significant step closer to understanding the fundamental constituents of the universe."
According to the standard cosmological model, the universe consists of about 25 percent dark matter and 70 percent dark energy around 5 percent normal matter, said Burns. Normal matter consists primarily of baryons - hydrogen, helium and heavier elements -- and observations show that about 40 percent of the baryons are currently unaccounted for. Many astrophysicists believe the missing baryons are in the WHIM, Burns said.
If it’s not in the sock drawer, try locker 813 down at Greyhound station.
Yale guys make up a word in an attempt to charge a dollar for a ten cent idea.
Humans Appear Hardwired To Learn By 'Over-Imitation'
ScienceDaily (Dec. 6, 2007) — Children learn by imitating adults--so much so that they will rethink how an object works if they observe an adult taking unnecessary steps when using that object, according to a new Yale study.
"Even when you add time pressure, or warn the children not to do the unnecessary actions, they seem unable to avoid reproducing the adult's irrelevant actions," said Derek Lyons, doctoral candidate, developmental psychology, and first author of the study. "They have already incorporated the actions into their idea of how the object works."
Learning by imitation occurs from the simplest preverbal communication to the most complex adult expertise. It is the basis for much of our success as a species, but the benefits are less clear in instances of "over-imitation," where children copy behavior that is not needed, Lyons said.
It has been theorized that children over-imitate just to fit in, or out of habit. The Yale team found in this study that children follow the adults' steps faithfully to the point where they actually change their mind about how an object functions.
The study included three-to-five-year-old children who engaged in a series of exercises. In one exercise, the children could see a dinosaur toy through a clear plastic box. The researcher used a sequence of irrelevant and relevant actions to retrieve the toy, such as tapping the lid of the jar with a feather before unscrewing the lid.
The children then were asked which actions were silly and which were not. They were praised when they pinpointed the actions that had no value in retrieving the toy. The idea was to teach the children that the adult was unreliable and that they should ignore his unnecessary actions.
Later the children watched adults retrieve a toy turtle from a box using needless steps. When asked to do the task themselves, the children over-imitated, despite their prior training to ignore irrelevant actions by the adults.
"What of all of this means," Lyons said, "is that children's ability to imitate can actually lead to confusion when they see an adult doing something in a disorganized or inefficient way. Watching an adult doing something wrong can make it much harder for kids to do it right."
Journal reference: Proceedings of the National Academy of Sciences: online publication week of December 3, 2007 (doi/10.1073/pnas.0704452104)
Co-authors include Andrew Young of the University of Wisconsin-Madison and Frank Keil of Yale, who was the senior author.
“Watching an adult doing something wrong can make it much harder for kids to do it right." Just spectacular. Bravo to you, gentlemen. And may we say that whoever paid for the study certainly got their money’s worth.
If they mean Prince, why don’t they just say Prince
Odd Little Star Has Magnetic Personality
ScienceDaily (Dec. 6, 2007) — A dwarf star with a surprisingly magnetic personality and a huge hot spot covering half its surface area is showing astronomers that life as a cool dwarf is not necessarily as simple and quiet as they once assumed.
Simultaneous observations made by four of the most powerful Earth- and space-based telescopes revealed an unusually active magnetic field on the ultracool low-mass star TVLM513-46546. A team of astronomers, led by Dr. Edo Berger, a Carnegie-Princeton postdoctoral fellow at Princeton University, is using these observations to explain the flamboyant activity of this M-type dwarf that lies about 35 light-years away in the constellation Boötes.
The team’s observations of TVLM513-46546 combine radio data from the Very Large Array, optical spectra from the Gemini North 8-meter telescope, ultraviolet images from the orbiting Swift observatory and x-ray data from NASA’s Chandra X-ray Observatory. This is the first time that such a powerful set of telescopes has been trained on one of the smallest known stars. The study is part of a program that looks at the origins of magnetic fields in ultracool dwarfs, stars that astronomers always assumed were simple, quiet, and more tranquil than their hotter and more massive siblings.
“With such a unique set of observations you always expect to find the unexp ected,” said Berger, “but we were shocked at the level of complexity that this object exhibits.”
The star’s steady radio emission is interrupted with spectacular fireworks displays of minute-long flares. These flares come from the catastrophic collisions and merging of the magnetic fields in the corona of the star; these actions drive the annihilation of magnetic energy like a giant short-circuits in the fields. The team also observed soft x-ray emission and an x-ray flare.
Also for the first time, the group charted optical hydrogen-alpha emission with a period of two hours that matches the two-hour rotation period of the star. “We find a hot spot that covers half of the surface of the star like a giant lighthouse that rotates in and out of our field of view,” said Berger. “We still do not know why only half of the star is lit up in hydrogen and if this situation remains unchanged over days, weeks, years, or centuries.”
Berger describes the dwarf star’s magnetic field as probably being a simple dipole (north-south orientation, like the Earth’s much weaker magnetic field) that extends out at least one stellar radius above the surface. There is also a smaller-scale field that has loops similar to those seen on the Sun, but smaller. “Those loops and arcs occur on random places on the surface of the star, “said Berger. “That’s where the flares originate that last only a few minutes, whereas the overall field doesn’t get disturbed.”
Objects like TVLM513-46546 were once thought to be models of stellar quiescence and simplicity, with little to no magnetic field activity. “Theory has always said that as we look at cooler and cooler stars, the coolest will be essentially dead,” said Berger. “It turns out that stars like TVLM513-46546 have very complex magnetic activity around them, activity more like our Sun than that of a star that is barely functional.”
This one’s complicated magnetic field environment and possible hot spot may indicate some unusual activity beneath the star’s surface (in its dynamo) or possibly even the existence of a still-hidden companion. The idea of an unseen companion as an explanation for the star’s excitable magnetic disposition is an intriguing one, says Berger, but no such object has yet been detected. “The main idea to consider here is an analogy to other systems where the presence of a companion directly or indirectly excites magnetic activity,” he said.
Like other ultracool dwarf stars, TVLM513-46546 is an M-type star with surface temperatures below about 2400K (2127 Celsius) and a mass of only 8 to 10% that of our Sun. By contrast, the Sun is a G-type star with an average surface temperature of 6000K (5727 Celsius).
Imagine the interior of the Sun layered like an onion. Its internal convection is the process by which heat from the nuclear fusion at the core is transported by large spinning currents that move through the Sun’s outer layers. Differential rotation is simply the term for the different spin rates of different layers. Together these motions of electrically charged gas spin up the magnetic field structures we see at the Sun.
By contrast, an ultracool M-type star like TVLM513-46546 is fully convective. That is, the zone that transports heat to the surface of the star extends all the way from the stellar surface into the center, like the bubble of a huge boiling pot. Such a simple structure has been predicted to generate a very basic magnetic field structure, perhaps more like the Earth’s than the complex fields we see on the Sun. Why TVLM513-46546 has such a complex field and activity remains to be studied.
In order to find out if this star is just a stellar oddity, or if it might turn out be a typical prototype of ultracool dwarfs, the research team plans to continue with observations of other such stars. The team expects the larger sample to show how other candidate low-mass stars (and brown dwarfs, objects too hot to be planets and too cool to be stars) generate magnetic fields. Berger also notes that he’d like to get more observations to try and spot any possible companions to such stars. “The issue of a possible companion is really pure speculation at this point,” he said. “However, I am trying to get observations that will assess this possibility.”
These results are being published in the February 10, 2008 issue of the Astrophysical Journal.
Partial studies of magnetic activity on these types of stars have been performed previously, but this is the first time that such a powerful set of telescopes has been simultaneously pointed at the same object.
Yeah, but is it purple?
What’s passing for science this week?
Sociologists think skiers are either too dumb or too lazy to turn on the Weather Channel.
City Dwellers Look To Backyards When Deciding To Head To Slopes
ScienceDaily (Dec. 6, 2007) — City dwellers are less likely to head to the slopes when their backyards are bare, even if New England ski resorts have many feet of packed power and ideal skiing conditions, according to new research from the University of New Hampshire.
The researchers found that the New England ski industry is directly impacted by the "backyard effect," which means that urban snow conditions significantly affect skier activity. Snow in urban backyards can be as important to ski businesses as snow in the mountains, according to the researchers.
Because snow and weather follow deeper climate trends, the research also has implications for understanding the potential consequences of climate change and how it could impact the New England ski industry. Since 1970, Northeast winters have warmed by an average of 0.70 °C/decade.
"Ski areas, emblematic of winter tourism, provide the economic engine for many rural regions. Their importance extends beyond employment and revenues of the ski area itself. Real estate booms in second homes and condominiums, and in migration by retirees and others, raise housing prices and transform communities in fundamental ways. Tax revenues, businesses, and the needs for infrastructure and social services change as well. If climate shifts directly affect ski areas, their indirect impacts ripple as well," according to the researchers.
The researchers studied two of the nation's oldest alpine resorts, both in New Hampshire: Cannon Mountain in the northwestern White Mountains and Gunstock Mountain Resort near Lake Winnipesaukee.
With the assistance of resort personnel, researchers obtained records of daily attendance through seven winter seasons at Cannon and nine winters at Gunstock. Weather and snow-condition indicators include daily snowfall, snow-depth and temperature for Boston, and Lakeport and Bethlehem, NH.
They found that attendance at the ski areas is more influenced by snowfall in Boston than at the resorts themselves. For example, a one centimeter increase in the previous day's snow-depth at Bethlehem, near Cannon, increases the predicted attendance by 11 skiers/snowboarders. On the other hand, a one centimeter increase in the previous day's snow-depth in Boston increases predicted attendance somewhat more, by 18 skiers, even though Boston snow might have no bearing on Cannon-area conditions.
"If this backyard effect reflects ignorance, then education is the cure -- skiers could be persuaded that great skiing exists in the mountains, even when their backyard is bare. The backyard effect might also partly reflect subtler dynamics, such as people who feel less like skiing, or perceive more activity choices, when conditions are not wintry near home," the researchers said.
Weekends and holidays also play a crucial role in ski resort attendance. The highest spikes in attendance on weekends and holidays occur at different times from one year to the next, however, because they are influenced by snow conditions and weather.
The results are particularly interesting in light of the continued investments made by ski resorts in snow-making infrastructure. "Snowmaking costs millions, but has become a competitive and climatic necessity in many places. Smaller, less capitalized resorts, and those in marginal climates, have trouble making the necessary investments -- a factor in their high failure rate, and the industry's consolidation into a smaller number of larger resorts," the researchers said.
The researchers are Cliff Brown, professor of sociology at UNH; Lawrence Hamilton, professor of sociology at UNH; and Barry Keim, former professor of geography at UNH and New Hampshire State Climatologist who is now at Louisiana State University.
The new research is published in the December issue of the International Journal of Climatology in the article, "Ski areas, weather and climate: time series models for New England case studies."
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