[原创]借块宝地练听力(每天一更新)

cvvt1986

借个地方练听力,版主别删我帖呀,我知道版主最好了,听力内容摘自Scientific American 我还是比较喜欢听广播,天天听训练有点受不了,偶尔听听广播调剂一下,60秒的内容,练练听写也不错.加油!!

Solar-Powered Sea Slug(我家乡特产)

http://podcast.sciam.com/daily/sa_d_podcast_081201.mp3

[此贴子已经被作者于2008-12-21 12:03:22编辑过]

cvvt1986

It may look like just another animal. But one kind of lowly sea slug actually has the solar power abilities of a plant. Bizarre but true, the sea slug carries out photosynthesis. This finding was published in the Proceedings of the National Academy of Sciences.

Usually, plants perform photosynthesis by way of tiny organelles called plastids. Plastids convert sunlight, water and carbon dioxide into usable nutrients. Then animals eat the plants. But the sea slug goes about it slightly differently.

It has at least one gene necessary for photosynthesis—so far it’s the only animal known with this ability. But it needs some help, the gene itself isn’t enough. So sea slugs eat algae. They slit open the organisms and suck out the cytoplasm. The slugs digest most of the algae, but those plastids remain whole and undigested. And then the plastids keep on doing what they do, which is convert sunlight to usable energy. Once the sea slug has eaten enough algae, and gained enough plastids, it can live off just sunlight for up to nine months. When it comes to energy, this slug needs no plug.

cvvt1986

Robot Clam Achieves Feat with Foot

http://podcast.sciam.com/daily/sa_d_podcast_081202.mp3

[此贴子已经被作者于2008-12-21 12:04:02编辑过]

cvvt1986

M.I.T. scientists have designed a new robot. You’ll probably never see it though—it’s meant to be hidden. Because it’s a robot clam. Engineers wanted to design a lightweight anchor that could be easily set and then picked up. That’s not possible with conventional anchors. A more talented anchor would be great for, say, small submarines that move around constantly to test ocean temperatures and currents.

Razor clams presented the ideal biological model. They can burrow a centimeter per second more than two feet down into the soil, where they can anchor themselves tightly to the ocean floor. Scientists set up a glass box with water and beads and stuck a living razor clam inside. They filmed what happened next. The animal’s foot wiggled into the beads. The rest of the clam followed by moving quickly up and down and rapidly opening and closing its shell. By carefully analyzing the film, the scientists discovered something surprising. The clam’s movements turn the sand around the creature into more of a fluid—basically quicksand. By copying this system, M.I.T. researchers created a tiny RoboClam. It’s the size of a cigarette lighter. If they add artificial intelligence, we can find out if the device is happy as a clam.

stnereids

感谢LZ~~~

这么好的帖子当然要顶起来~~~~~~

cvvt1986

Happiness Is Contagious

如果打不开,地址:http://podcast.sciam.com/daily/sa_d_podcast_081205.mp3

[此贴子已经被作者于2008-12-21 12:06:02编辑过]

cvvt1986

Want to live a happier life? Try surrounding yourself with happy friends or at least find friends with happy friends. A study published online December 4th in the British Medical Journal says happiness can quickly go viral within your social network.

Researchers looked at twenty years' worth of data on more than 5,000 individuals and found that when any one person was happy, their friends became more likely to share that joy. Benefits spread out to three degrees of separation, meaning a better chance at happiness for not only their friends' friends, but also their friends' friends' friends.

But don't go thinking your ten thousand buddies on Facebook will bring you happiness. The researchers found that the strength of the effect dissipates over physical distance, with next-door neighbors and friends living nearby getting the biggest boost. Surprisingly, sadness made very little headway within social networks, paling in comparison to the communal effects of happiness. Just in time for the holiday season, scientific proof that it's not the gift that counts—it’s the smile on the face of the friend giving it.

—Adam Hinterthuer 

cvvt1986

Warm Climates Support Longer Limbs

 

http://podcast.sciam.com/daily/sa_d_podcast_081208.mp3

cvvt1986

Animals that live in cold climates tend to have stubby limbs—shorter arms and legs—even smaller ears and tails. Picture a penguin and you’ll see what I mean. Biologists have long assumed that these stumpy appendages are an evolutionary adaptation. Shorter extremities minimize heat loss, so animals that are more compact are better suited to the cold.

But scientists from Ohio say that temperature may have a more direct effect on the length of an animal’s limbs. Because they find that turning up the heat helps cartilage grow—results that were published in the Proceedings of the National Academy of Sciences.

The researchers raised mice at several different temperatures, and they confirmed that those kept at a balmy 80 degrees were longer limbed than those who lived at a more chill 45. But how does a little heat make mice more leggy? The answer, they find, lies in the cartilage. Long bones grow from the cartilage found at either end. And the warmer it is, the more that cartilage grows, even when it’s just sitting in a test tube. Which I guess means it’s possible that the dog days of summer lead to longer-legged dogs.

—Karen Hopkin 

cvvt1986

Gift-Giving for Lovers

http://podcast.sciam.com/psych/sa_p_podcast_081215.mp3