科学美国人sss整理2.docx

_20120814SSS
Five-hundred years ago, a 15-year-old Incan girl was sacrificed, along with two other children. Her mummy has now revealed that she had an active lung infection at her death. Because a technique called shotgun proteomics has been used to determine whether someone was actually suffering from a disease rather than just carrying it. The report appears in the journal PLoS ONE. [Angelique Corthals et al., Detecting the Immune System Response of a 500-Year-Old Inca Mummy]

Previous research into ancient diseases has used DNA analysis to determine the presence of pathogens. But with DNA, there's no way to tell latent infections from the full-blown, misery-inducing ones.

Researchers analyzed protein samples from the mummies of two of the slain children. The girl's proteins indicated an immune response to bacteria, perhaps a pathogen related to tuberculosis. Other evidence, such as mucus under her nose and lung abnormalities, strengthened the diagnosis. The seven-year-old boy, on the other hand, showed no signs of infection.

This is the first time the technique has been used. It’s a small sample, but further development of shotgun proteomics has the potential to improve our understanding of ancient disease, as well as assisting in tomorrow’s forensic investigations.

_20120416SSS
This is Scientific Americans 60 second Science, I am Cythia Graber

Spring is in the air. And so are those dang insects, hungry for a blood meal. The victim can wind up with a bunch of bites, red and itchy. So what drugs can quench that itch? Maybe none, according to a study in the Drug and Therapeutics Bulletin. 

Researchers reviewed the literature on a variety of treatments. Topical antihistamines? Generally not recommended. They’re only marginally effective and shouldn't be used for longer than three days.

Oral analgesics like ibuprofen are sometimes recommended, but the scientists say there’s no evidence supporting that. Topical anesthetics such as lidocaine are only marginally effective and can sensitize the skin—meaning the itching could ultimately get worse.

And common topical steroids like hydrocortisone? The problem here is that they’re not supposed to be used on broken skin. And if you’ve been scratching, that skin may already be broken.

The authors recommend a simple approach: clean the area, and use a cold pack to tamp down inflammation and numb the nerves. If you haven’t broken the skin, try the steroid cream. But your best approach may be ice. The cold hard fact is that this cold hard treatment works.

Thanks for the minute for cientific Americans 60 second Science, I am Cythia Graber

_20120227SSS
This is Scientific Ameican 60 second Science, I'm Cynthia Graber, this will just take a minute!

Cave painting connects us with our prehistoric artist ancestors. But there's a dearth of such illustration in the Americas. Now a cave in Brazil has been found to house the oldest New World image known. 

The shelter was excavated from 2002 to 2009. In the last days there, scientists exposed a foot-high figure in the bedrock. It has a c-shaped head, two outstretched arms, two legs, and a very visible penis.

Using radiocarbon dating, the researchers dated an ash layer to between 9300 and 10,500 years ago. A hearth found about an inch above the drawing gives similar results. And the researchers used a technique called optically stimulated luminescence on sediment, which also dated to around 10-12,000 years ago.

The scientists say this makes the petroglyph the oldest reliably dated cave art in the Americas. The research was published in journal Public Library of Science One. 

Echoes of this style exist in other early art in the region, amidst diverse styles throughout North and South America. The researchers the range of images reveals a spectrum of symbolic thought dating back to early in the history of human colonization of the hemisphere.

Thanks for the minute, for Scientific American 60 second Science, I'm Cynthia Graber.

_20120223SSS
This is Scientific American 60 second Science, I'm Sophie Bushwick, got a minute

In the lab, female rodents sometimes terminate their pregnancies after being exposed to new males. It’s called the Bruce effect, for researcher Hilda Bruce. Now a study in the journal Science finds that the Bruce effect occurs in the wild, and likely ups evolutionary fitness.

To discover whether the Bruce effect is a naturally occurring adaptive strategy, researchers from the University of Michigan observed a wild population of gelada monkeys. They measured hormones in the animals’ feces to identify pregnant females and their conception dates.

Gelada monkeys live in small groups, with several females and a single male. When a rival displaces the male in a gelada family, he frequently kills his predecessor’s progeny. And the females know it. The researchers found that females impregnated by the old male terminate 80 percent of their pregnancies after the new male takes over.

Those females were quicker to conceive again with the new male than were females who hadn’t been pregnant. Rather than producing offspring at risk of death, females subject to the Bruce effect invest in new progeny—with a better chance of survival.

Thanks for the minute for scientific American 60 second science, I'm Sophie Bushwick。

_20120316SSS
This is Scientific American 60 Second Science, I'm Cynthia Graber, this will just take a minute~

You know the scene—it’s a Friday night, and your date just canceled. You’re bummed, maybe a little hurt. You think now might be a good time for a beer, maybe a bourbon. And you have good company: fruit flies. Turns out that sexually deprived male fruit flies hit the bottle more frequently than sexually satisfied ones.

Researchers placed one group of males repeatedly in a container with females who’d already mated. Those females were no longer receptive to sex. So the males learned to stop trying.

The scientists placed another group with virgin females, who were receptive. Then they offered the two groups of males a choice of food. One choice was supplemented with ethanol. And the sexually frustrated flies dove for the drink in significantly greater numbers.

This behavior was also predicted by a particular neuropeptide in the flies’ brains. The sexually deprived flies had a low level of the molecule. The scientists found they could moderate the flies’ alcohol-seeking behavior just by upping this molecule. The research was published in the journal Science.

The finding could help explain how addiction may be determined both by the brain and by social conditions—especially when those are tough to swallow.

Thanks for the minute, for Scientific Americans 60 second Science, I am Cynthia Graber.

_20120809SSS
This is scientific American sixty seconds science, I'm Cynthia Graber, this will just take you a minute.

Tea and coffee are drunk worldwide, far beyond their original ecological niches. Now it looks like another caffeinated beverage also gained popularity far from its home.

Archaeologists call it Black Drink—a caffeinated brew of toasted leaves and twigs of the holly plant. It was imbibed, often ceremonially, in many regions of the Americas. Researchers say they’ve found the earliest trace of Black Drink—in a region that doesn’t grow holly.

They investigated Cahokia, a large pre-Columbian political body. It encompassed floodplains and hills near today’s Saint Louis. It’s tough to find plant matter, so scientists searched for traces of theobromine, caffeine and ursolic acid in ceramics in the right proportion—a sort of chemical signature for holly. And they were able to date Black Drink back to about the year 1050, almost a thousand years ago. But the nearest holly grows hundreds of miles away.

The findings are in the Proceedings of the National Academy of Sciences. The researchers say this is the earliest evidence of Black Drink consumption. And that Black Drink was traded for ritual consumption far from where it was grown. Much like our morning cup of joe.

Thanks for the minute for scientific American sixty seconds science. I'm Cynthia Graber.

_20121228SSS
When autumn rolls around, the leaf peepers come out in force. Armed with digital cameras, they record the most spectacular displays of fall foliage. Well according to a study in the journal Functional Ecology [Toshie Mizunuma et al., The relationship between carbon dioxide uptake and canopy colour from two camera systems in a deciduous forest in southern England], those images may be more than just pretty pictures. They may represent a new way to monitor climate change.

Trees take carbon dioxide, or CO2, from the atmosphere and convert it into biomass. By sopping up CO2 they help to stabilize the climate. But at the same time, they’re also affected by climate, for example, budding earlier in the season as global temperatures rise.

To understand how all this balances out, ecologists monitor how forests take up CO2. It’s a costly business that involves using a network of 500 instrument towers worldwide. So researchers got to wondering whether there might be an easier way to keep an eye on photosynthesis. And they found that digital cameras do the trick.

Analyzing two years’ worth of snaps taken every half hour in a forest in southern England, the researchers discovered that a tree’s leafy colors provide a good proxy for its photosynthetic productivity. So next time you go for a walk in the woods, take only photos. And leave only data points.