【Phat Yeti出品】60-SECOND SCIENCE 官方听力文稿 + 讨论帖 （更新至：2008.03.07）

sxczUID: 2159731

sxczUID: 2159731

sxczUID: 2159731

60-Second Science_ July 2, 2008
Sea Bacteria Produce Methane
Scientists thought that only bacteria that live where there's no oxygen produced methane, a greenhouse gas. But new research shows that ocean bacteria also give off the gas. Karen Hopkin reports

Methane is a greenhouse gas that traps heat even better than carbon dioxide. It comes from a variety of sources, including fossil fuel production and even farming. Cows give off methane, ya know, after they eat. Even the surface waters of the ocean contain substantial amounts of this gas. But where that marine methane comes was a mystery. Until now.
Scientists collected seawater off the coast of Hawaii. And they found that bacteria that live in these waters scarf up certain phosphorous-containing chemicals, and then release methane as a byproduct. The results appear online in the journal Nature Geoscience. What’s surprising is that scientists had previously thought that methane’s only produced by bacteria that live in places where there’s no oxygen, think of the smell you associate with a swamp or with the muck at the bottom of a murky pond. This marine methane could contribute to global warming by adding more greenhouse gases to the atmosphere. What’s worse, the hotter it is, the more stressed these seafaring bacteria get, and the more methane they’re likely to put out. Which was certainly not the kind of feedback that atmospheric scientists were hoping to get.
—Karen Hopkin

sxczUID: 2159731

sxczUID: 2159731

sxczUID: 2159731

sxczUID: 2159731

sxczUID: 2159731

60-Second Science_ July 3, 2008

Connectomics: Mapping the Nervous System
In an effort that in some ways makes the human genome project look simple, scientists are attempting to map the trillions of connections among neurons in any person. Cynthia Graber reports

It took 13 years and countless hours of research to unravel the human genome. Now neuroscientists want to do their field’s version. A small group of researchers is advancing the emerging field of what they call “connectomics.” As genomics moved from individual genes to the entire genome, so connectomics wants to take us from individual neurons in our brain to the connections and wiring in the entire nervous system network. That involves nerve cells, the axons that stretch out like wires, the synapses that transmit information.
It’s a daunting task—you have about a hundred billion neurons in your brain. Connectomics wouldn’t be possible without computer processing and imaging. This allows researchers to look at a maze of axons in a sample and determine just which axon is connected to which neuron. It’s as complicated as it sounds. Jeff Lichtman is a Harvard scientist whose lab is at the forefront of this effort. He says detailing the connections in a single human brain would require data storage equivalent to Google’s entire collection. But the effort’s underway. Lichtman says Connectomics could teach us how the brain processes information, and how we develop and learn. Which, he says, is what makes us human.
—Cynthia Graber

sxczUID: 2159731

sxczUID: 2159731

sxczUID: 2159731

sxczUID: 2159731

sxczUID: 2159731

60-Second Science_ July 7, 2008

Vaccinate Networks, Not Everyone

By vaccinating those individuals with the largest social networks, whole populations could be protected from disease outbreaks more efficiently. Karen Hopkin reports

You’ve probably heard of the whole six degrees of separation thing. It predicts that, on average, you’re no more than six links away from any other person on the planet. Like your roommate runs into a woman whose brother is a writer for Desperate Housewives. Which means you’re only six invites away from having lunch with Marcia Cross’s nannies.

The concept stems from the fact that people have social networks, and those networks tend to intersect. But the importance of this “small world” phenomenon extends beyond whose email address you have on your Blackberry. Now scientists think they can take advantage of these networks to design more efficient vaccination programs.

According to an international team of physicists, the most effective way to protect a population from disease is to immunize people who have the largest networks. If you can keep the most highly connected people from infecting their friends, neighbors, co-workers, you can halt an epidemic. And you may only have to vaccinate half the number of people you would normally. The findings will appear in an upcoming issue of Physical Review Letters. The biggest problem with such a program—people are bound to feel left out when they’re told that they don’t need a shot.

—Karen Hopkin



[ 本帖最后由 sxcz 于 2008-7-14 21:31 编辑 ]

sxczUID: 2159731

sxczUID: 2159731