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Jupiter
Jupiter is changing its stripes, perhaps because its
seasons are changing, scientists reported on Thursday.
The orbiting Hubble Space Telescope is capturing some of the most
dramatic atmospheric changes ever documented, the team at NASA and the
Space Telescope Science Institute in Baltimore reported.
White areas of the planet's cloud bands are turning brown and brownish
areas are lightening up, the researchers said.
"It does this every once in a while," planetary scientist Amy
Simon-Miller of the NASA Goddard Space Flight Center said in a telephone
interview.
"Jupiter doesn't stay the same color all the time. We are just lucky --
it is going through what we call a global upheaval, meaning the belts
and bands are changing color at the same time."
The changes, described in detail at http://hubblesite.org/news/2007/25,
might be due to seasonal effects, Simon-Miller said.
"Jupiter's year is much longer than an Earth year -- it's 12 years," she
said.
Changes in the heat from the sun may be affecting the gas giant's
atmosphere, she said. As planets orbit, their angle from the sun varies,
changing how directly the sun's rays hit and in turn causing the
seasons.
Genetic study has confirmed what archeologists have
suspected for decades -- the "Cradle of Civilization" is also the
birthplace of the house cat.
All domestic cats, from the scrawny strays prowling the markets of Asia
to the purebred reclining on the bed of a doting owner, descend from a
tabby-like sub-species living in North Africa, the researchers reported
on Thursday.
The near Eastern wildcat, known scientifically as Felis silvestris
lybica, is the likely ancestor of all the cats whose genes were sampled
by the team, they report in Friday's issue of the journal Science.
"Domestic cats throughout the entire world had a common ancestor and
that common ancestor lived in the Near East. There was no separate
domestication in Europe or South Africa or China," said Carlos Driscoll
of the National Cancer Institute and the University of Oxford in
Britain.
"The domestication of wild species to complement human civilization
stands as one of the more successful 'biological experiments' ever
undertaken," wrote the researchers, led by Dr. Stephen O'Brien of the
National Cancer Institute, in their report.
"For cats, the process began over 9,000 years ago as the earliest
farmers of the Fertile Crescent domesticated grains and cereals as well
as livestock animals." The Fertile Crescent stretches from modern-day
Egypt to Iran.
Preserved remains show that cats were valued by Egyptians, and one
skeleton unearthed in Cyprus in 2004 showed that people were keeping
cats as pets more than 9,000 years ago.
Driscoll, who admits he is a cat person, adds: "You are not civilized
without a cat."
MOTHER OF ALL CATS
All domestic cats and small wildcats belong to the same species -- Felis
silvestris. But there are wildcat sub-species in many regions of the
world.
The international team studied the genes of 979 domestic cats as well as
some of the animals that may have been their ancestors -- the European
wildcat or Felis silvestris silvestris, the Near Eastern wildcat or
Felis silvestris lybica, the Central Asian wildcat, the sub Saharan
African wildcat and the Chinese desert cat.
They found that each of the Felis silvestris subspecies, falls into a
genetically distinct group, or clade. Some of the Near Eastern wildcats
and all the domestic cats fell into the same clade.
And their lineage is far more ancient than anyone suspected, originating
more than 100,000 years ago. Driscoll is quick to stress, however, that
the first cats were not being kept as pets by the pre-humans that
existed then.
"We weren't out of Africa. We hadn't even domesticated ourselves yet,
much less anything else," Driscoll said.
O'Brien has been studying the genetics of cats for years, hoping to
uncover links to disease.
"Cats are a model for human genetic disease," Driscoll said. "Cats are
also really good models for brain development."
Even brief exposure to secondhand smoke in bars and
restaurants can result in measurable levels of a toxin in workers'
bodies that is known to cause lung cancer, U.S. researchers said on
Thursday.
They found nonsmoking workers in Oregon who worked a single shift in a
bar or restaurant that allowed smoking were more likely to have a
detectable level of NNK -- a carcinogen linked with lung cancer -- in
their bodies than those who worked in nonsmoking establishments.
"NNK is only found in the body as a result of either smoking or
breathing other people's smoke," said Michael Stark of the Multnomah
County Health Department in Portland, Oregon, whose study appears in the
American Journal of Public Health.
Stark and colleagues studied 52 nonsmoking bar and restaurant workers
who were exposed to smoke at work, and compared them to 32 similar
nonsmoking workers from communities in Oregon that prohibited smoking in
such places.
For the study, participants, mainly young, uninsured women, gave urine
samples before and after working at least four hours.
"As a group, four out of five of the nonsmokers who worked in a smoking
environment had some detectable level of this deadly chemical in their
body, and as a group, for every hour that they worked, that level
increased by 6 percent," Stark said in a telephone interview.
Other studies have shown that nonsmokers exposed to secondhand smoke
have about a 20 percent higher risk of lung cancer. They are also at a
higher risk of asthma and perinatal complications such as sudden infant
death syndrome.
"This adds to the very strong and growing body of evidence that
second-hand smoke exposure is dangerous and people need to be
protected," Stark said.
According to Stark, clean indoor air acts protect about 70 percent of
workers from exposure to tobacco smoke.
Secondhand smoke causes about 3,400 lung cancer deaths and 46,000 heart
disease deaths in adult nonsmokers in the United States each year,
according to the American Lung Association.
Levels of environmental smoke in restaurants and bars are two to five
times higher than in homes with smokers, they said.
Anthropologists in northern Peru have found evidence of
peanut, cotton and squash farming dating back 5,000 to 9,000 years,
researchers said on Thursday, in a finding that helps pin down the start
of organized agriculture in the Americas.
Farming marks an important turning point in human history because it
signals a change from a nomadic hunter-gatherer way of life to more
settled, sedentary society.
"This seems to be a major shift for the development of social
structures," said Tom Dillehay, professor of anthropology at Vanderbilt
University in Nashville, Tennessee, whose findings appear in the journal
Science.
"The crops are dependent on people, which ties the latter down,"
Dillehay said in comments e-mailed to Reuters.
Anthropologists assumed early farming was taking place in the Andes
Mountains, but Dillehay and colleagues managed to find proof.
They discovered peanuts, squash and cotton, as well as a primitive grain
and various tubers and fruits on the western slopes of the Andes.
"Agriculture played a more important and earlier role in the development
of Andean civilization than previously understood," Dillehay and
colleagues wrote.
"Our data also show that horticulture and cultural complexity developed
in the Americas nearly as early as it did in many parts of the Old
World."
They dated the squash from about 9,200 years ago, the peanut from 7,600
years ago and the cotton from 5,500 years ago.
These plants did not grow wild where they were found, and Dillehay
believes they must have been domesticated somewhere else. They also
found garden plots, irrigation canals and storage structures nearby.
Dillehay believes the development of agriculture served as a catalyst
for cultural and social changes that led to the development of towns and
political structures in the Andes highlands and along the coast some
4,000 to 5,000 years ago.
The discovery in Peru parallels the 1997 discovery by the Smithsonian's
Bruce Smith that ancient squash seeds found in Oaxaca, Mexico, were
nearly 10,000 years old.
"It reveals another specific environment where early agriculture
advanced," Dillehay said of his finding.
Scientists have taken a first step toward making
synthetic life by transferring genetic material from one bacterium into
another, transforming the second microbe into a copy of the first.
They intend to use their technique to custom-design bacteria to perform
functions such as producing artificial fuel or cleaning up toxic waste,
the researchers report in Friday's issue of the journal Science.
"This is equivalent to changing a Macintosh computer to a PC by
inserting a new piece of software," Craig Venter, a genome pioneer who
now heads his own institute in Rockville, Maryland, told reporters in a
telephone briefing.
"I think eventually we could make artificial cells," Venter added. "This
is a first step."
Venter has been trying for years to create a microbe from scratch. This
is not quite it, but his team re-programmed one species of bacteria by
adding in the genetic material from a closely related species.
They gene-engineered the replacement chromosome to resist an antibiotic
and then flooded their experiment with the drug. The bacteria that
survived all carried only the genes that had been spliced in.
They believe all the others simply died, but they are in fact not sure
how the new DNA re-programmed some of the bacteria or what happened to
the original DNA.
"I think that we don't know for certain how the donor genome takes
over," Venter Institute researcher Ham Smith told reporters.
Nonetheless, Venter's team has applied for a patent on the process and
they hope to exploit it industrially. Venter believes it will be
relatively straightforward to build a new chromosome from scratch, one
that performs the desired functions, to create a custom-made bacterium.
"What we are reporting in this Science paper is not anything about a
synthetic organism," Venter said.
BOOTING UP LIFE
"It's a key enabling step so that once we have a synthetic chromosome we
know it is now possible to boot that up. So synthetic biology itself and
synthetic genomics is much closer to being proven," Venter added.
"We look forward to having fuels from genetically modified organisms
within the next decade and perhaps in half that time."
The key to the experiment was using a very simple bacterium called
Mycoplasma capricolum, which often infects goats. Bacteria do not have a
nucleus as do cells from more complex organisms.
The research team injected a chromosome from a related species called
Mycoplasma mycoides.
They do not know how well it worked but at least some of the M.
capricolum were transformed into what looked and acted like M. mycoides.
The scientists concede it will be much more difficult to do this with
more complex organisms, even bacteria, that have cell walls and all
sorts of defensive mechanisms to keep out foreign
DNA.
A non-profit Canadian organization called the ETC Group expressed
concern about the experiment and Venter's patent application. "We are
extremely concerned about the breadth and implications of this patent
and of its monopoly claims," the group's Jim Thomas said in an e-mail.
"We will be requesting that patent offices worldwide refuse this
patent."
But Venter defended the patent. "At every stage of what the team has
done here over the past several years, we have had to develop novel
technologies and approaches that have not existed before because the
field has not existed before," he said.
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