Imagine this: an American
student receives a couple of pills in the mail. She assumes they are
drugs she picked up from an online pharmacy. She takes them and develops
a cold. Soon, she's shedding millions of virus particles and infecting a
number of people in her college. The next week, the president of the US
is scheduled to speak on campus. Most of those attending have a cold.
When the president arrives, the virus particles descend on him. But in
him, they don't cause a cold. They react with a specific DNA sequence in
his cells, and cause a fastacting neural disease that causes memory
loss and then death.
This may sound like the plot of a future
Mission Impossible movie, but Andrew Hessel , an expert on genetics and
microbiology, and Mark Goodman, a global security specialist , argue in
The Atlantic that such a scenario will soon be possible. Advances in
genetic engineering and biotechnology have come to the stage where
viruses targeting select individuals with specific sequences in their
DNA can be deployed as tools of assassination. In fact, governments are
already preparing for this. In 2009, Ronald Kessler, an award-winning
investigative journalist, revealed that Navy stewards gather everything
that the US president has touched - be it toothbrushes or towels — and
sanitize and destroy them in an effort to keep potential enemies from
obtaining his genetic material. The same year, US secret cable
09STATE37561 asked State Department personnel posted in Africa to
collect "data ... include(ing) ... fingerprints, facial images , DNA,
and iris scans" of leaders of Burundi, Rwanda, Uganda and the Democratic
Republic of the Congo.
Moore's law - "every 12 months (it is
now 24 months), the number of transistors on an integrated circuit will
double" - applies equally to the field of genetic engineering, Goodman
and Hessel claim. They quote Bill Gates as saying that if he were a kid
today he wouldn't be hacking computers, he'd be hacking biology. The
costs of genetic engineering have dropped dramatically. The science of
synthetic biology makes DNA design and synthesis much easier.
Geneticists have already begun tweaking existing designs and creating
new ones. Independent
Craig Ventner, the American
scientist responsible for sequencing the human genome - describing the
complete set of human genetic information - was also the first to create
an artificial cell. The costs of building personally targeted
bioweapons have also come down. What cost Craig Ventner $300 million in
2007 can now be done at a fraction of that cost and with far less skill.
The four building blocks of DNA - Adenine, Guanine, Cytosine and
Thymine - translate easily into computer symbols. The power of computer
processing makes creating drugs that will affect only a person with a
specific DNA sequence so easy that it can soon be outsourced to biology
students, claim Hessel and Goodman. Right now, DNA hacking is targeted
at finding cures for specific cancer mutations, but according to Jimmy
Lin, a genomics researcher who works on designing treatments for rare
childhood diseases based on individual genetic analysis, "when you're
familiar with the research, it's really feasible that a well-funded
group could pull this (genebased kill) off."
Cosmic 'fog' produced by ancient starlight measured
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Agencies : Washington, Sat Nov 03 2012, 13:19 hrs
Using NASA's Fermi Gamma-ray Space Telescope, scientists determined how many gamma rays should be emitted at different energies.
More distant blazars show fewer gamma rays at higher energies - especially above 25 GeV - thanks to absorption by the cosmic fog.
Researchers then determined the average gamma-ray attenuation across three distance ranges between 9.6 billion years ago and today.
From this measurement, the scientists were able to estimate the fog's thickness.
The average stellar density in the cosmos is about 1.4 stars per 100 billion cubic light-years, which means the average distance between stars in the universe is about 4,150 light-years.
"The Fermi result opens up the exciting possibility of constraining the earliest period of cosmic star formation, thus setting the stage for NASA's James Webb Space Telescope," said Volker Bromm, an astronomer at the University of Texas.
"In simple terms, Fermi is providing us with a shadow image of the first stars, whereas Webb will directly detect them," Bromm said in a NASA statement.
Measuring the extragalactic background light was one of the primary mission goals for Fermi.
"We're very excited about the prospect of extending this measurement even farther," said Julie McEnery, the mission's project scientist at NASA's Goddard Space Flight Center.
Gamma rays are the most energetic form of light. Since the Fermi's launch in 2008, its Large Area Telescope (LAT) observes the entire sky in high-energy gamma rays every three hours, creating the most detailed map of the universe ever known at these energies.
Mars --clues of lost atmosphere
Curiosity ingests Mars air and finds clues of lost atmosphere
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Agencies : Washington, Sat Nov 03 2012, 16:44 hrs
Learning what happened to the Martian atmosphere will help scientists assess whether the planet ever was habitable. The present atmosphere of Mars is 100 times thinner than Earth’s.
A set of instruments aboard the rover has ingested and analysed samples of the atmosphere collected near the “Rocknest” site in Gale Crater where the rover is stopped for research.
Findings from the Sample Analysis at Mars (SAM) instruments suggest that loss of a fraction of the atmosphere, resulting from a physical process favouring retention of heavier isotopes of certain elements, has been a significant factor in the evolution of the planet. Isotopes are variants of the same element with different atomic weights.
Initial SAM results show an increase of 5 percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed. These enriched ratios of heavier isotopes to lighter ones suggest the top of the atmosphere may have been lost to interplanetary space.
Losses at the top of the atmosphere would deplete lighter isotopes. Isotopes of argon also show enrichment of the heavy isotope, matching previous estimates of atmosphere composition derived from studies of Martian meteorites on Earth.
Scientists theorize that in Mars’ distant past its environment may have been quite different, with persistent water and a thicker atmosphere. NASA’s Mars Atmosphere and Volatile Evolution, or MAVEN, mission will investigate possible losses from the upper atmosphere when it arrives at Mars in 2014.
... contd.
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