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01-10-2009, 04:02
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חבר מתאריך: 21.07.06
הודעות: 423
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Laser that kills
Rocket Scientists Shoot Down Mosquitoes With Lasers
Humans, Butterflies Remain Unharmed; The 'Star Wars' Connection
Robert A. Guth
BELLEVUE, Wash. -- A quarter-century ago, American rocket scientists proposed the "Star Wars" defense system to knock Soviet missiles from the skies with laser beams. Some of the same scientists are now aiming their lasers at another airborne threat: the mosquito.
In a lab in this Seattle suburb, researchers in long white coats recently stood watching a small glass box of bugs. Every few seconds, a contraption 100 feet away shot a beam that hit the buzzing mosquitoes, one by one, with a spot of red light.
The insects survived this particular test, which used a non-lethal laser. But if these researchers have their way, the Cold War missile-defense strategy will be reborn as a WMD: Weapon of Mosquito Destruction.
Weapons of Mosquito Destruction
A new global arms race is escalating: the one to protect us from the mosquito.
"We'd be delighted if we destabilize the human-mosquito balance of power," says Jordin Kare, an astrophysicist who once worked at the Lawrence Livermore National Laboratory, the birthplace of some of the deadliest weapons known to man. More recently he worked on the mosquito laser, built from parts bought on eBay.
The scientists' actual target is malaria, which is caused by a parasite transmitted when certain mosquitoes bite people. Ended in the U.S. decades ago, malaria remains a major global public-health threat, killing about 1 million people annually.
Efforts to eradicate the disease languished for years until recently.
Big-money donors like Bill Gates, the United Nations, the U.K. and non-profit such as Malaria No More re-launched the war on malaria, devoting billions of dollars to vaccines, methods of prevention and novel ways to kill mosquitoes.
"You can say we are very lucky -- the right place at the right time," says astrophysicist Szabolcs Márka, a Columbia University specialist in black holes. He has a grant to develop a "mosquito flashlight" designed to knock out the bugs' eye-like sensors.
Scientists around the world are testing ways of thwarting mosquitoes with microwaves, rancid odors, poisoned blood and other weapons that disrupt the sense of sight, smell and heat mosquitoes use to find their prey.
There's work on genetically altering a bacterium to infect and kill a mosquito, and a project to build a malaria-free mosquito genetically enhanced to overtake the natural kind.
There's also a researcher in Japan who thinks mosquitoes can be a force for good. He is working on transforming them into "flying syringes" that deliver vaccines with every bite.
The mosquito laser is the brainchild of Lowell Wood, an astrophysicist who worked with Edward Teller, father of the hydrogen bomb and architect of the original plan to use lasers to shield America from the rain of Soviet nuclear arms.
President Ronald Reagan embraced the idea in the 1980s, dubbing it the Strategic Defense Initiative.
Senator Edward Kennedy mocked it as "Star Wars." Eventually it became a footnote in history.
Its rebirth as a bug killer came thanks to Nathan Myhrvold, a former Microsoft Corp. executive who now runs Intellectual Ventures LLC., a company that collects patents and funds inventions. His old boss, Mr. Gates, had asked him to explore new ways of combating malaria. At a brainstorming session in 2007, Dr. Wood, the Star Wars architect, suggested using lasers on mosquitoes.
Soon Dr. Wood, Dr. Kare and another Star Wars scientist teamed with an entomologist with a Ph.D in mosquito behavior and other experts. They killed their first mosquito with a hand-held laser in early 2008.
"We like to think back then we made some contribution to the ending of the Cold War" with the Star Wars program, Dr. Kare says. "Now we're just trying to make a dent in a war that's actually gone on a lot longer and claimed a lot more lives."
The scientists envision their technology might one day be used to draw a laser barrier around a house or village that could kill or blind the bugs. Or, laser-equipped drone aircraft could track bugs by radar, sweeping the sky with death-dealing photons.
They now face one big challenge: deciding how strong to make the weapon. The laser has to be weak enough to not harm humans and smart enough to avoid hitting useful bugs. "You could kill billions of mosquitoes a night, and you could do so without harming butterflies," says Mr. Myhrvold.
Demonstrating the technology recently, Dr. Kare, Mr. Myhrvold and other researchers stood below a small shelf mounted on the wall about 10 feet off the ground. On the shelf were five Maglite flashlights, a zoom lens from a 35mm camera, and the laser itself -- a little black box with an assortment of small lenses and mirrors. On the floor below sat a Dell personal computer that is the laser's brain.
The glass box of mosquitoes across the room is an old 10-gallon fish tank. Each time a beam strikes a bug, the computer makes a gunshot sound to signal a direct hit.
To locate individual mosquitoes, light from the flashlights hits the tank across the room, creating tiny mosquito silhouettes on reflective material behind it. The zoom lens picks up the shadows and feeds the data to the computer, which controls the laser and fires it at the bug.
In a video, researchers showed what happens when they deploy deadly rays.
A mosquito hovers into view. Suddenly, it bursts into flame. A thin plume of smoke rises as the mosquito falls. At the bottom of the screen, the carcass smolders.
There's ready supply of fresh recruits nearby, where an intern feeds a saucer of goat blood to a colony of Anopheles stephensi, one species of mosquito that transmits malaria.
Not only can the laser target a mosquito, it can also tell a male from a female based on wing-beat.
That's a crucial distinction, since only females feed on blood and thus transmit disease. Males in the wild eat sugary plant nectar. (In the lab they get raisins.)
"If you really were a purist, you could only kill the females, not the males," Mr. Myhrvold says. But since they're mosquitoes, he says, he'll probably "just slay them all."
Source: http://online.wsj.com/article/SB123680870885500701.html
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