Salty sweat may leave trace fingerprints on metal


 

A new crime-fighting technique could make avoiding capture more difficult for even the most fiendish gunsels.

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A thinner, tougher display puts screens on more gadgets.

 

 

  

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Our experts tackle the big questions that keep you up at night
If you started just before the first dinosaurs appeared, you’d probably be finishing your hike just about now.
Here’s how it breaks down: One light-year—the distance light travels in one year, used as the yardstick for interstellar distances—is about 5.9 trillion miles. If you hoofed it at a moderate pace of 20 minutes a mile, it would take you 225 million years to complete your journey (not including stops for meals or the restroom). Even if you hitched a ride on NASA’s Mach 9.68 X-43A hypersonic scramjet, the fastest aircraft in the world, it would take about 95,000 years to cover the distance.
You’ll need to bring a big bag, too; walking such a distance requires substantial supplies. The average adult burns about 80 calories per mile walked, so you’d need two trillion PowerBars to fuel your trip. You’d also produce a heap of worn-out shoes. The typical pair of sneakers will last you 500 miles, so you’d burn through some 11.8 billion pairs of shoes. And all that effort wouldn’t get you very far, astronomically speaking: The closest star to the sun, Proxima Centauri, is 4.22 light-years away.

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Boy scouts: forget the moss. A new study shows that cows may sense Earth’s magnetic field



Lost in drive-by country? Look for a cow. It will probably be pointing north—or south.


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A buyer's guide to harnessing the energy of the sun



Dear EarthTalk: I am considering solar panels for my roof to provide heat for my hot water and possibly to do more than that. Are there some kinds of solar panels that are better than others? How do I find a knowledgeable installer? --Elise, Watertown, MA


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You wouldn't begrudge the creators of what is probably the most perfectly flat mirror ever a moment of vanity. But rather than studying their own reflections, the Spanish scientists hope to use it to create a new type of microscope.


Electron microscopes use a beam of electrons to magnify samples by up to 2 million times. But whatever they look at takes a beating, a problem when examining delicate biological specimens.


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Patchy blockade
The trade embargo that sometimes bites


FOR almost half a century, the United States has imposed a trade embargo against Cuba. And yet it sometimes seems barely visible. Across the island, American brands are ubiquitous. Tourists can order a Coca-Cola (made in Mexico) in state-run hotels. Computers running Microsoft software have appeared in the capital’s few electronics stores. A fleet of Ford tankers refuel aeroplanes at Havana’s airport. Taking advantage of an exemption introduced in 2000, American farmers have become Cuba’s biggest source of food imports, a cash trade worth $600m a year. No wonder that some Cubans wonder whether the “blockade” which the government blames for nearly all of Cuba’s problems might be some sort of Orwellian trick. “Does it really exist?” asks a medical student in Havana. “I don’t know what to believe anymore.”


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Lots of amphibians (a third to a half of all species) are dying, and their deaths are the breaking-edge of what many scientists are calling the first mass extinction since the dinosaurs checked out 65 million years ago, researchers say in a new paper published online in the Journal Proceedings of the National Academy of Sciences.

Scientists are not sure when this extinction crisis began—it could have started 10,000 years ago, or during the industrial revolution, or this century. But we are definitely seeing an extinction “spasm” right now, say the Berkeley scientists, especially among our clammy, froggy friends. This extinction is unlike the five that came before it, according to the paper’s authors from UC Berkeley, because it has nothing to do with any asteroid impact, or volcanic surge, or great sea cooling. Instead, it may have almost everything to do with us. Amphibians made it through last time, when the dinosaurs disappeared. But with new, people-driven pressures on biodiversity, the survivors are now some of the most vulnerable.

Almost 200 amphibian species have gone extinct in the last few decades alone, with several pressures adding to the crisis. One is a fungal skin disease called chytridiomycosis, which has been implicated in mass frog deaths in Central and South America, and is claiming species almost everywhere else on earth, according to the paper. Scientists believe the disease spreads on amphibians introduced by humans into new environments. Climate change is also implicated, possibly as a trigger for chytrid infections, but also as a force of its own. Many amphibian species are adapted to live only in a small temperature zone, and montane species are particularly vulnerable to temperature shifts that can shrink the small slice of mountainside they inhabit down to nothing.

Habitat loss is another important player, impacting 90 percent of the amphibian species the IUCN lists as at risk of extinction. Warming (and the weather changes that go along with warming) shrinks habitats, as does humanity’s constant bulging expansion over more and more of the earth. Research into treatments for chytrid is ongoing, with new results with beneficial skin bacteria, but with human-caused climate change progressing, and habitats shrinking, the papers authors close their report with the worry that we may not be able to make a dent in this latest mass extinction, and even if we can, we have very, very little time to do so.

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Chinese officials have admitted that they are concerned about the lack of spectators at some Olympic events.

They have hired volunteers, dressed in yellow shirts, to fill up empty venues and improve the atmosphere inside.

But Wang Wei, a senior official with the Beijing organising committee (Bocog), said other Olympics had experienced similar problems.

The comments came after spectators and journalists noticed that certain venues were far from full, even though all events are sold out.

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Did iron cyclones give Earth a wonky core?

IT'S not just the sphere of culture that has an east-west divide. The Earth's inner core of solid iron also behaves differently in each hemisphere, transmitting seismic waves faster in the eastern side than in the west.

The phenomenon has baffled scientists, but now numerical simulations developed by Julien Aubert of the French national research centre's Institute of Geophysics in Paris and his team suggest that the anomaly may be due to subterranean "cyclones" found in parts of the liquid iron outer core.

These swirling cyclones drag cooler material from the top of the outer core right down to the bottom, where iron is gradually crystallising onto the solid inner core. This cooling causes crystals to form more quickly and with random alignments. That makes the material stronger, which in turn means it is able to carry seismic waves more quickly.

Aubert's work indicates that for the past 300 million years most of these iron cyclones will have been found below Asia, so most of the cooling effect will have been in the eastern hemisphere. Over that time, the inner core has grown by about 100 kilometres, and on the eastern side of the core that layer should have formed from the fast-transmission crystals.

wonky搖晃的

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AOL drags Time Warner income down

AOL continued to weigh on Time Warner as the media group reported a 26 percent drop in second-quarter income on Wednesday, largely because of weakness at its internet division.

AOL, which has emerged as the biggest challenge confronting Jeff Bewkes, chief executive, suffered a drop of 36 percent in operating income as as it continued to shed paying subscribers. Advertising revenue, which AOL is banking on as its future, rose only 2 per cent.

Mr Bewkes blamed the performance on difficulties from integrating the acquisitions that AOL had made since announcing an advertising-focused strategy two years ago.

He expressed optimism for the remainder of the year. Yet Mr Bewkes also noted that Time Warner had arranged for the separation of AOL's internet access business and its online advertising platform – a move that could hasten a potential sale.

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Invisible Bullet-Tagging Technology Could Deter Criminals

A breakthrough nanotech coating for cartridges in firearms can transfer hard-to-remove tags to gun offenders and better capture DNA

Gun-slinging evil-doers beware. Scientific justice is just around the corner thanks to a new nanotechnology system that not only better captures DNA on guns, but attaches hard-to-remove, microscopic tags to the hands and clothing of criminals who fire their weapons. Developed in the U.K., the tags are a unique blend of naturally-occurring pollen, known for its extraordinary adhesive properties, and nanotechnology particles. The composition can be used as an abrasive coating to capture skin cells on gun cartridges, usually too smooth or shiny to retain much evidence in the way of fingerprints or DNA. The tags in the coating also transfer themselves to anyone handling the cartridges and are very difficult to wash off.

But the benefits of the nanotechnology don't stop there. Most evidence is usually destroyed after a gun is fired, because of the heat generated. The coating has been designed to avoid such heat damage and can even be varied subtly for every cartridge batch, making it easier for officials to tie guns back to the offenders. The breakthrough technology is cost-effective and could potentially be put to use within a year. Researchers may also consider applying the system to other weapons like knifes.

nanotech: (n)奈米技術

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Limits to China's pledge of change 
China promised an open Olympics for the media, and to promote human rights and democracy, in its bid for the Games. To see if it was true to its word, BBC Panorama reporter John Sweeney spent five weeks criss-crossing the country, following the torch relay.

Fang Zheng is the kind of person who sums up the Olympic ideal. He lost his legs in what was, officially, a "traffic accident" and subsequently won golds in an all-China competition.

But when the torch came through his home town of Hefei, he was not there.

Fang's story tells you something about just how open modern China is.

"It wasn't a traffic accident," he told me. "The truth is that on June 4th 1989 when I was withdrawing from Tiananmen Square, I was chased from behind by a tank and both of my legs were crushed."

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