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Comment: Re:sounds overly optimistic (Score 1) 79

by JRIsidore (#43383041) Attached to: German Scientists' Visible Light Network Hits 3Gbps

... it's a UV diode with a phosphor on it, not a blue diode.

Nope. Just look at the spectrum of some white LEDs, they clearly peak around 450 nm plus what the phosphor delivers. UV is very problematic as it quickly degrades the plastic optics which are predominantly used with LEDs. Plus, you would only get the yellow light from the phosphor, not white light. It's the mixture of blue and yellow that's necessary where the ratio determines the correlated color temperature.
E.g.: http://www.cree.com/led-components-and-modules/products/xlamp/discrete-directional/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/XLampXPG2.pdf

Earth

Climate Change Could Drive Coffee To Extinction By 2080 345

Posted by timothy
from the right-here-in-ponca-city dept.
Hugh Pickens writes "Coffee is the world's favorite beverage and the second-most traded commodity after oil. Now Nick Collins reports that rising global temperatures and subtle changes in seasonal conditions could make 99.7 per cent of Arabica-growing areas unsuitable for the plant before the end of the century and in some areas as soon as 2020. Even if the beans do not disappear completely from the wild, climate change is highly likely to impact yields. The taste of coffee, a beverage of choice among Slashdot readers, will change in future decades. 'The worst case scenario, as drawn from our analyses, is that wild Arabica could be extinct by 2080,' says Justin Moat. 'This should alert decision makers to the fragility of the species.'" Read more, below.

Comment: Re:Beware of too many LEDs (Score 1) 113

by JRIsidore (#39955047) Attached to: Researchers Conquer "LED Droop"
What they did is they compared the light of LEDs and HID to that of sodium lamps, mostly found in outdoor lighting (for those who don't RTFA). The blue light, which is missing in the sodium spectrum, supresses the melatonin production. The same process happens every morning when you get up and turn on the light or go outside. As sodium lamps are mostly used in streetlighting etc. I think this is actually a benefit instead of being dangerous. Supressing the melatonin fights the fatigue which might prevent some car accidents, although I'm not sure if this effect is high enough for this.
It's funny.  Laugh.

Scambaiting Gets Comical; Internet Scammers All Dressed Up 178

Posted by timothy
from the made-in-the-shadenfreude dept.
Nurse Nasty writes "Scambaiting is a fun and relaxing full-contact email sport. It's all about baiting Internet and email scammers into exposing themselves and sharing that humiliation with the entire world. Recently I baited four different groups of Internet scammers into being comic book action super-heroes, and then giving them their own 10-page graphic novel. It's a bit of fun and eduction through entertainment." (Warning: The comic contains a bit of naughty language.)
Biotech

Scientists Write Memories Directly Into Fly Brains 137

Posted by Soulskill
from the hellllllp-me dept.
TheClockworkSoul writes "Researchers at the University of Oxford have devised a way to write memories onto the brains of flies, revealing which brain cells are involved in making bad memories. The researchers said that in flies, just 12 brain cells were responsible for what is known as 'associative learning.' They modified these neurons by adding receptors for ATP, so that the cells activate in the presence of the chemical, but since ATP isn't usually found floating around a fly's brain, the flies generally behave just like any other fly. Most interestingly, however, is that the scientists then injected ATP into the flies' brains, in a form that was locked inside a light-sensitive chemical cage. When they shined a laser on the fly brains, the ATP was released, and the 'associative learning' cells were activated. The laser flash was paired with an odor, effectively giving the fly a memory of a bad experience with the odor that it never actually had, such that it then avoided the odor in later experiments. The researchers describe their findings in the journal Cell."
It's funny.  Laugh.

Treasured "Moon Rock" Is Petrified Wood 209

Posted by CmdrTaco
from the keep-yer-hands-off-my-treasure dept.
Hugh Pickens writes "BBC reports that a treasured piece at the Dutch national museum — a supposed moon rock from the first manned lunar landing given to former Prime Minister Willem Drees during a goodwill tour by the three Apollo-11 astronauts shortly after their moon mission in 1969 — has been revealed as nothing more than petrified wood, curators say. A jagged fist-size stone with reddish tints, it was mounted and placed above a plaque that said, 'With the compliments of the Ambassador of the United States of America... to commemorate the visit to The Netherlands of the Apollo-11 astronauts.' The plaque does not specify that the rock came from the moon's surface. Researchers from Amsterdam's Free University said they could see at a glance the rock was probably not from the moon. They followed the initial appraisal up with extensive testing. 'It's a nondescript, pretty-much-worthless stone,' wrote Geologist Frank Beunk in an article published by the museum. Beunk says the rock, which the museum at one point insured for more than half a million dollars, was worth no more than $70. The 'rock' had originally been been vetted through a phone call to NASA. As the US Embassy in the Hague said it was investigating the matter, the Rijksmuseum says it will keep the piece as a curiosity."
Earth

Earth's Period of Habitability Is Nearly Over 756

Posted by kdawson
from the nice-while-it-lasts dept.
xp65 writes "Scientists at this year's XXVIIth General Assembly of the International Astronomical Union in Rio de Janeiro, Brazil agree that we do not yet know how ubiquitous or how fragile life is, but that: 'The Earth's period of habitability is nearly over on a cosmological timescale. In a half to one billion years the Sun will start to be too luminous and warm for water to exist in liquid form on Earth, leading to a runaway greenhouse effect in less than 2 billion years.' Other surprising claims from this conference: that the Sun may not be the ideal kind of star to nurture life, and that the Earth may not be the ideal size."
Displays

Finally, a True Green Laser 274

Posted by timothy
from the greenwashing-is-everywhere dept.
dusty writes "Remember those green lasers from Star Wars? Turns out that faking green lasers has been easy for years, but making true green laser diodes has been the stuff of science fiction. Until recently, that is. Now researchers from Japan have created the world's first true green laser diode. Until now, only red and blue laser diodes were available, and now with the addition of green, new TVs and projectors that are more efficient can be produced. And if you were wondering how green lasers pointers are already produced, it is a hack that involved doubling the frequency of an infrared laser. The new true green laser diodes have much higher efficiency than the current 6%, leading many to expect big time laser display breakthroughs in the near future. Ars Technica has a well-written article on this breakthrough."

Comment: Re:Self Cleaning (Score 1) 388

by JRIsidore (#28778777) Attached to: Laser Ignition May Replace the Spark Plug
Not really. With high power lasers you really should make sure your optics are clean. Not so much for the energy loss of the beam but for damage of the optics. Any dirt on a lens or mirror will partially reflect some light which propagates back into the lens and is eventually being focused therein. For low power lasers this is harmless but when you go to high power this little amount of light is able to form a plasma when focused and hence destroy the optics. Since they try to ignite the gasoline I assume it is a somewhat powerful laser. If it is the optics might be damaged by soot, if not the soot will just stay there and you'll have to remove it manually.
Television

Futurama Voices Could Be Recast 260

Posted by Soulskill
from the bite-my-shiny-metal-*** dept.
Svippy writes "According to reports surfacing on the Internet, Futurama may be recast. The animated series is due to return next year on Comedy Central, but may not be the same as we once knew it. 'As part of the announcement, the show's producers said stars including West, Sagal and DiMaggio had all signed on to return. Turns out that wasn't true. The stars had all expressed interest in returning. But with the budget for Futurama dramatically slashed, the salary offers came in well below what the thesps were asking.' Phil LaMarr posted 20th Century Fox's request for auditions on his Facebook page. However, some are skeptical about whether it's a real casting call or purely a stunt to reduce the salaries of the voice actors."

Comment: Re:Longer lifetimes is the answer (Score 1) 627

by JRIsidore (#27456359) Attached to: Quantum Setback For Warp Drives
Nitpick... the time dilation for a constant relative velocity is, as the term 'relative velocity' suggests, symmetrical. People on earth see the ships clocks go slower as the crew sees the clocks on earth go slower. Both age at the same rate, that's the Twin Paradoxon of special relativity.
A constant high velocity is not the reason why this works, you have to take the acceleration into account a real ship would have to undergo.

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