Telling time on Saturn

Friday, May 3, 2013

A University of Iowa undergraduate student has discovered that a process occurring in Saturn's magnetosphere is linked to the planet's seasons and changes with them, a finding that helps clarify the length of a Saturn day and could alter our understanding of the Earth's magnetosphere.

Saturn's magnetosphere is the third largest structure in the solar system, eclipsed only by the magnetic fields of the sun and Jupiter. Unlike Earth, which has a visible rocky surface and rotates once every 24 hours, Saturn is composed mostly of clouds and liquid gas layers, each rotating about the planet at its own rate of speed. This variation in rotation made it difficult for scientists to pin down time for the planet.

Decades ago, a strong and naturally occurring radio signal, called Saturn kilometric radiation (SKR), was believed to give an accurate measurement of a Saturn day. But data gathered by an ESA/NASA spacecraft proved otherwise.

Now, using data from NASA's Cassini spacecraft, which entered orbit around Saturn in 2004, UI space physicist Donald Gurnett and other scientists showed that the north and south poles have their own SKR "days" that vary over periods of weeks and years. How these different periods arise and are driven through the magnetosphere has become a central question of the Cassini mission, according to NASA officials.

The discovery by Tim Kennelly, a UI junior majoring in physics and astronomy, is one of the first direct observations of seasonal changes in Saturn's magnetosphere. In addition, the finding carries over to all planets having a magnetosphere, including Earth.

"I'm pleased to have contributed to our understanding of Saturn's magnetosphere so early in my career," says Kennelly, the lead author of the paper published online in the American Geophysical Union's (AGU) Journal of Geophysical Research. "I hope this trend continues."

Scientists have known for some time that Saturn's magnetospheric processes are linked together, from the activity generating the SKR emission relatively near the planet to the periodic signatures in Saturn's magnetosphere stretching millions of miles downstream in the planet's magnetotail. But they didn't know how they were linked.

Kennelly analyzed phenomena recorded between July 2004 and December 2011 by Cassini's UI-built Radio and Plasma Wave Science (RPWS) instrument and came to some novel conclusions about how the events are linked. First, he looked at inward-moving "flux tubes" composed of hot, electrically charged gas, called plasma. Focusing on the tubes when they initially formed and before they had a chance to dissipate under the influence of the magnetosphere, he found that the occurrence of the tubes correlates with activity in the northern and southern hemisphere depending upon the season.

Kennelly found that during winter in the northern hemisphere, the occurrence of flux tubes correlates with SKR period originating in the northern hemisphere. A similar flux tube and SKR correlation was noted for the southern hemisphere during southern winter. The events are strongly ordered, he says, and follow Saturn's seasonal changes.

This finding may alter how scientists look at the Earth's magnetosphere and the Van Allen radiation belts that affect a variety of activities at Earth ranging from space flight safety to satellite and cell phone communications.

Commenting on his research experience, Kennelly says, "I'm really happy with the support I've received from Don Gurnett's group. They let me do a lot of the research on my own. I'm really appreciative." He adds that he will begin applying to graduate schools next semester and plans to earn his doctorate in plasma physics.

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University of Iowa: http://www.uiowa.edu

Thanks to University of Iowa for this article.

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Source: http://www.labspaces.net/128124/Telling_time_on_Saturn

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PFT: Reid says Albert to play LT, Fisher to be RT

AP

NFL teams have different options when it comes to filling out the quarterback depth chart.? They can have an unquestioned starter and obvious backups, or they can throw the quarterbacks in a blender and see who earns the job.

Or they can pretend to have a clear-cut starter and undermine him with a backup who says he supports the starter but actually wants to take his job.

That?s what the Jets did last year by adding Tim Tebow to the team.? Even though Tebow tried to say and do all the right things on multiple occasions, he wanted to play.? Which means that he wanted Sanchez to not play.

On Thursday, Sanchez reflected on their relationship, making it clear that there was tension.

?If you were Tim?s agent or my agent, would you say that?s the absolutely best position for either of us?? Probably not,? Sanchez told reporters.? ?Tim wanted to play, I wanted to play, only one guy plays at this position.? So I guess it wasn?t the most advantageous, but that?s the way things happen. We both competed [with] our best, tried to be the best of friends we could, and honestly under different circumstances we would be really good friends, it?s just hard when you?re competing like that.? There?s just a professionalism about it that you don?t get too close to guys like that.? You?re just professional, and you?re cool and if the guy has a flat tire on the side of the road, I?m going to stop, I?m not just going to blow by him, but at the same time, I?m not sending him gifts on his birthday or anything.?

This year, the Jets have abandoned the fa?ade, embracing the notion that not just Mark Sanchez and Geno Smith but all five quarterbacks currently on the roster are competing.? Which means that Sanchez will view the rookie the same way he regarded Tebow.

?I don?t see why it would be any different,? Sanchez said.? ?I will help [Smith] out as much as I can, but when we have to compete, we have to compete, that?s the way it goes.?

Which means that the quarterback position will continue to display dysfunction, with five guys clamoring for one job.? While competition could make the guy who emerges from the scrum better, like so many quarterback controversies the guy who wins the job for Week One essentially becomes the guy who wins the privilege of being the first one to get benched.

That?s why the far better approach for any NFL team is to have a starter and obvious backups.? It keeps the locker room from picking sides, the media from stirring up trouble, and the fans from ripping their hair out.

Eventually, that could happen for the Jets, with Smith getting the job once he?s deemed ready to handle it.? Until then, the Jets will keep Sanchez and his guaranteed salary of $8.25 million around, because they?ll be paying him whether he?s on the team or not.

Which means that, essentially, the Jets have done a 180 from 2012.? Last year, they pretended there wasn?t a competition when in fact there really was one.? This year, the organization has launched a competition with an obvious preferred winner in mind.

Source: http://profootballtalk.nbcsports.com/2013/05/02/reid-says-albert-will-play-left-tackle-fisher-will-play-right/related/

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Flight of the RoboBee: Tiny hovering robot creates buzz

The successful controlled flight of the tiny RoboBee ? designed by a team at Harvard ??represents a key step in the development of insect-size drones with a range of potential uses.

By Pete Spotts,?Staff writer / May 2, 2013

Five individual robotic flies of identical design are shown alongside a U.S. penny for scale, demonstrating that the manufacturing process facilitates repeatability and mass production.

Courtesy of Kevin Ma, Pakpong Chirarattananon

Enlarge

A robotic fly with a body not much taller than a penny standing on edge has taken to the air, passing its tests with flying colors. The Robobee, as it's called, is the smallest artificial insect yet flown, according to the team that built it.

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It lifts off the table, hovers, and flies in different directions. At this point in its evolution, the bug is still tethered by thin wires that allow its designers to power and guide it. And landing remains an issue. The robot ends its sorties with all the grace of a mosquito nailed with a burst of Raid.

Still, the tiny craft's success ? the team that designed it said it was the first such object to fly in a controlled manner ? represents a key step in developing insect-size drones that designers say could one day search collapsed buildings for survivors after a disaster, sample an environment for hazardous chemicals before humans are sent in, or pinpoint enemy soldiers or terrorists holed up in urban areas.

Some members of the team suggest that future generations of the bug could serve as a robotic pollinator for plants, though without the side benefit of honey.

Over the years, researchers have marveled at insect flight in no small part because it appears to violate every principle that keeps a bird or an airliner aloft.

Together with an announcement this week that another team of researchers has developed a bug-like compound lens for collecting video taken with small aerial vehicles, the description of RoboBee appearing in Friday's issue of the journal Science signals how far robotic bug research?in the past decade.

"Just fantastic," enthuses John Rogers, who heads the Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign, when asked about RoboBee. Dr. Rogers guided the team that developed the artificial compound lens.

RoboBee is something of a misnomer. The team modeled its bug after a hoverfly, which looks like a bee. Hoverflies show remarkable control over their movements ? from hovering, as the name implies, to lightly touching down on a wind-tossed blossom.

The hoverfly wanna-be was built by researchers and graduate students at Harvard University and weighs a scant .003 ounces. Its wingspan stretches just over an inch, and its wings flap up to 120 times a second, with each stroke covering an angle of 110 degrees ? all comparable to a hoverfly's characteristics. Each of the two independently controlled wings weighs about .00003 of an ounce.

The bug is far too small for hardware typically used in robots as stand-ins for muscles and joints, so the team "had to develop solutions from scratch, for everything," said Harvard engineering professor Robert Wood, who led the team, in a prepared statement.

The body of the bug was made from carbon-fiber composites with thin plastic strips serving as joints. The team crafted muscles from thin layers of ceramics that expand and contract when electricity is applied to them. The bug's overall power consumption is a paltry .019 of a watt ? so small a flashlight bulb wouldn't notice.

Over the past two years, the team has refined the manufacturing process to such a degree that they can replace a bug that augers in fairly quickly. In the past six months, the team has gone through 20 prototypes, according to Kevin Ma, a graduate student at Harvard's School of Engineering and Applied Sciences and one of two lead authors on the formal research paper appearing in Science.

The team's next challenge is to gradually move the bug from tethered to increasingly autonomous. At some point, that means it needs to see where it's going.

One potential solution appears in Thursday's issue of the journal Nature, where an international team ? including Kenneth Crozier, with Harvard's Schools of Engineering and Applied Sciences ? formally unveiled an artificial eye similar in design to the eyes of a fire ant or bark beetle. It boasts an array of 256 microlenses, 180 of which are used for imaging. Each of these imaging lenses sits atop a light sensor. All sitting in tidy order on a half sphere.

In nature, this arrangement gives insects an extraordinary field of view and an ability to keep virtually everything they see in focus, no matter how close or distant.

In the past, researchers have developed layouts that mimic to some degree a compound eye, but the arrays have been either flat, or hemispherical but laboriously hand crafted.

The team the University of Illinois's Rogers guided found a way to use elastic materials to give the overall array the shape it needed without throwing the microlenses and the light sensors each was paired with out of alignment. The compound lens is just under half an inch wide.

In an e-mail, Rogers says the team hopes to improve the compound lens's resolution ? its ability to distinguish between two closely spaced objects. Indeed, he says he's confident that the approach will yield lenses that outperform even the best insect eyes.

"We are working on that, and on schemes that allow the overall size of the camera to be reduced," he says, including a size befitting a RoboBee.

Source: http://rss.csmonitor.com/~r/feeds/csm/~3/hOVUjL6Oo6U/Flight-of-the-RoboBee-Tiny-hovering-robot-creates-buzz

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Saudi Arabia reports 3 cases of SARS-like virus

May 1 (Reuters) - Post position for Saturday's 139th Kentucky Derby at Churchill Downs after Wednesday's draw (listed as barrier, HORSE, jockey, trainer) 1. BLACK ONYX, Joe Bravo, Kelly Breen 2. OXBOW, Gary Stevens, D. Wayne Lukas 3. REVOLUTIONARY, Calvin Borel, Todd Pletcher 4. GOLDEN SOUL, Robby Albarado, Dallas Stewart 5. NORMANDY INVASION, Javier Castellano, Chad Brown 6. MYLUTE, Rosie Napravnik, Tom Amoss 7. GIANT FINISH, Jose Espinoza, Tony Dutrow 8. GOLDENCENTS, Kevin Krigger, Doug O'Neill 9. OVERANALYZE, Rafael Bejarano, Todd Pletcher 10. PALACE MALICE, Mike Smith, Todd Pletcher 11. ...

Source: http://news.yahoo.com/saudi-arabia-reports-3-cases-sars-virus-184904983.html

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Cicadas get a jump on cleaning

Apr. 29, 2013 ? As cicadas on the East Coast begin emerging from their 17-year slumber, a spritz of dew drops is all they need to keep their wings fresh and clean.

Researchers at Duke University and James Cook University in Australia have shown that dew drops can be beneficial not only in cleaning cicada wings, but other water-repellant surfaces. On these so-called superhydrophobic surfaces, dew drops "jump" by themselves, carrying away the contaminants.

A team led by Chuan-Hua Chen, Alfred M. Hunt Faculty Scholar and assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering, demonstrated that tiny particles such as pollen can be removed from cicada wings by a phenomenon he has described as jumping droplets. When growing dew drops coalesce together, the merged drop jumps off water-repellant surfaces. The jumping motion is automatic, powered entirely by the surface energy initially stored in the dew drops.

Using a specially designed high-speed video imaging system, the engineers captured the jumping water droplets on a cicada wing, as well as the associated self-cleaning processes.

"The ability of water-repellant surfaces to self-clean has conventionally been attributed to rain droplets picking up dirt particles," Chen said. "For this conventional wisdom to work, rainfall must be present and the orientation has to be favorable for gravity to effectively remove the rain droplets. These limits severely restrict the practical use of self-cleaning superhydrophobic surfaces.

"We have found, however, that the self-propelled jumping motion of the dew drops is very effective in dislodging contaminating particles, regardless of the orientation," Chen said. "These new insights can help guide the development of man-made surfaces that are not dependent on any external forces and are therefore truly self-cleaning."

The results of Chen's research were published online in the journal Proceedings of the National Academy of Sciences. Katrina Wisdom, a Duke undergraduate and a Pratt Research Fellow in Chen's lab at the time of this study, was the paper's co-first author.

Cicadas are flying insects typically a few inches long. The most common species emerge on a yearly basis, with some U.S. species arriving every 17 years. When they dig out from underground as nymphs they molt, shedding their skin to reveal their wings. They then take flight as full-grown cicadas, spending the next four to six weeks flying around searching for and attracting mates with their distinctive song. After depositing eggs in the ground, the cicadas die and the cycle begins anew.

Cicada wings are characterized by rows and rows of tiny bumps or domes of various heights and widths. They look like upside-down ice cream cones, with the conical tips projecting upward. When a water droplet lands on this type of surface, it only touches the points of the bumps, creating pockets of air underneath the droplet. The droplet is kept aloft by this cushion of air, much like the puck in an air-hockey game.

"Most cicadas are unable to clean their own wings because of their short appendages," said Gregory Watson of James Cook University. "Furthermore, these insects commonly live in areas where there is little rain over an extended period of time. However, the areas are humid, which provides the tiny dew droplets needed to 'jump clean' their wings."

"These findings point to an alternative route to achieve self-cleaning which is fundamentally different from the conventional wisdom involving rolling or colliding droplets on a superhydrophobic surface," Chen said. "Self-cleaning surfaces using the jumping-drop mechanism can work at any orientation, which is a huge advantage for applications with unfavorable orientations with respect to gravity, such as mobile electronics and building roofs."

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Story Source:

The above story is reprinted from materials provided by Duke University, via EurekAlert!, a service of AAAS.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Katrina M. Wisdom, Jolanta A. Watson, Xiaopeng Qu, Fangjie Liu, Gregory S. Watson, and Chuan-Hua Chen. Self-cleaning of superhydrophobic surfaces by self-propelled jumping condensate. PNAS, April 29, 2013 DOI: 10.1073/pnas.1210770110

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/strange_science/~3/38HgLVt4phs/130429154101.htm

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The Military's New Flying Gas Station Will Be Open 24/7 Anywhere in the World

KC-135 Stratotanker planes have been refueling fighter craft in-flight for more than 60 years. While such longevity is commendable, the US military?s fleet of mid-air refuellers is in desperate need of an update. And that?s where this new flying gas station comes in.

Read more...

Source: http://feeds.gawker.com/~r/gizmodo/full/~3/u8JEgFlDJ7s/the-militarys-new-flying-gas-station-will-be-open-24-7-484398864

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Art raises Multiple Sclerosis awareness | The CLog

Source: http://clclt.com/theclog/archives/2013/04/30/art-raises-multiple-sclerosis-awareness

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