Data
NUMBERS BY JEREMY JACQUOT
Number of operational warheads in the U.S.
nuclear stockpile, according to the Pentagon. That
figure is down from a peak of 3 1,225 weapons in
1967. Bulletin of the Atomic Scientists estimated
in 2009 that Russia has 4,830 operational warheads; the Soviet arsenal topped out at around
45,000 weapons in 1986. The new Strategic Arms
Reduction Treaty would limit both countries to
1,550 operational warheads each.
5113
Nuclear
Weapons
Estimated number of
nuclear weapon storage
sites worldwide, according to the International
Panel on Fissile Materials.
Russia has the most, with
48; the United States is
second, with 15 domestic
and 6 foreign sites. The
total number of nuclear
weapons worldwide is
approximately 20,350,
with about half of those
operational.
CHEMISTRY BEAT
ENVIRONMENT BEAT
THE BODY’S
MASTER SWITCH
Acetylation—the addition of a small clump
of atoms called an acetyl group—may be
the most important body process you have
never heard of: It activates and deactivates
proteins, thereby regulating access to our
DNA and helping control gene expression.
The latest research suggests that this protein tagging is even more influential than
scientists had previously believed. If so,
learning to manipulate it could yield powerful new approaches to treating disease.
In one study, biochemist Kun-Liang
Guan of the University of California at San
Diego and colleagues examined proteins in
human liver tissue. They found that more
than a thousand of the proteins, including
virtually every enzyme associated with
metabolism, were acetylated. The discovery implies that acetylation helps regulate
how the body gets its energy. Metabolic
problems contribute to conditions such as
diabetes, cancer, and obesity. “We hope
that by using acetylation, we can prevent
and cure disease,” Guan says.
Meanwhile, biochemist Chunaram
Choudhary of the University of Copenhagen looked at human cancer cells and
identified 1,750 acetylated proteins, 240
of which also turned up in Guan’s results.
Choudhary says that deliberately turning
proteins on or off through acetylation may
be a simple and efficient approach that
offers “a good chance of treating some of
the worst human diseases.” BO ZHANG
The unaltered
stomach
contents
of a young
albatross on
Midway Atoll.
CLEANUP TIME ON THE HIGH SEAS
Although the Laysan albatross chicks
of Midway Atoll National Wildlife Refuge
live in the central Pacific, more than 1,000
miles from human civilization, their stomachs look like miniature garbage dumps,
full of bottle caps, toothbrushes, cigarette lighters—even golf balls. A recent
survey of the marine debris plaguing the
island, home to the largest albatross colony in the world, is helping researchers
understand the sources of this far-flung
pollution. It is also pointing to simple
ways to reduce the problem.
A 2009 pilot study examined the
types, sources, and amounts of beach
debris on Midway Atoll. Preliminary
results show that of all the items col-
lected and identified from beach sites,
57 percent came from land sources and
43 percent were fishing-related gear and
debris. The most common objects were
beverage bottle caps and spacer tubes
used in the oyster industry. John Klavit-
ter, deputy refuge manager with the U.S.
Fish and Wildlife Service, estimates that
albatross chicks collectively consumed
more than four tons of plastic at Midway
last year. Independent marine debris
researcher Seba Sheavly, who coordinat-
ed the study, hopes that news of these
findings might spur small but important
changes in consumer behavior. “If people
just became aware of the need to recycle
bottle caps along with bottles, that would
help tremendously,” she says.
