...
Copyright 2001 Scientific American, Inc.Copyright 2001 Scientific American, Inc.
or
Life
By Rakesh K. Jain and Peter F. Carmeliet
Copyright 2001 Scientific American, Inc.Copyright 2001 Scientific American, ... 2001 Scientific American, Inc.
36 SCIENTIFIC AMERICAN DECEMBER 2001
BETTMANN/CORBIS
Profile
of the most-talked-about environmental issues of the
20t...
... radar and laser altimeter,
which together can determine the thick-
ness of the ice and the nature of the
underlying rock. With Robin E. Bell of
the Lamont-Doherty Geological Obser-
vatory, the co-leader ... fac-
tors,Ó Gendelman says. The NMDA re-
ceptor could be that pathway.Ó
And gp120 has a role in this activi-
ty as well. Not only does the viral pro-
tein stimulate t...
... conclusion. De-
spite the hype surround-
ing the Þeld, the experts
wrote, Òthere is a substan-
tial gap between the tech-
nology that is available
and the technology that is
needed to realize the po-
tential ... loners. The
families have very diÝerent char-
acters, which reßect the person-
ality of the matriarch. In the
case of Echo, the family is low-
key and nonagg...
... planet. The
spacecraft examined the outer
expanses of the earthÕs magnet-
ic Þeld and took the Þrst mea-
surements of the moonÕs far
side since the days of the Apol-
lo program. These images re-
vealed ... first slide the
trousers off onto the rope, then push one
leg through the other. The outside leg is
reversed twice in the process, leaving the
trousers on the...
... leishmani-
asis is being conducted, and the “pep-
tideria,” where the synthesized peptides
that form the basis of the malaria vac-
cine are stored. He also points out myr-
iad other labs and the entrance ... because the
power and economy of mass-
produced processors are often
cited as factors in the collapse
of the supercomputing market. As
much cheaper and easier-to-u...
... self-
expression and access to all informa-
tion. The Web can help people to un-
derstand the way that others live and
love and are human, to understand the
humanity of people,” Berners-Lee ex-
pounds, ... mega-
hertz. By analyzing the peaks and val-
leys and how they change as the fre-
quency rises, Sinha’s software calculates
the density of the hidden material, the...
... back-to-back on a common
piece of tetracene. One FET injects elec-
trons, and the other injects holes; in the
middle they annihilate and produce yel-
low-green light (it should be easy to mod-
ify ... of the spec-
trum known as L-band as the worldwide
standard for digital radio. The U.S. dis-
agreed, preferring a solution known as
in-band, meaning that the digital signal
would...
... Molecule
OXYGEN
Copyright 2001 Scientific American, Inc.
Scientific American March 2001 19www.sciam.com
News & Analysis
R
ENO, NEV. The Chicxulub Cra-
ter, sprawled across the Gulf of
Mexico and the Yucatán Penin-
sula, ... off the dimers and breaking
the DNA strand next to them, the en-
zymes initiate a repair process that other
cellular enzymes complete.
Daniel Ya...
... strategies and the cost-benefit dimensions
of what the response should be if they do one or the oth-
er.” He concludes: “We have the evolved capacity to adopt
either strategy.” These are hardly the words ... studies such the-
ories. Artificial-intelligence and Web re-
searchers have co-opted the term for their
own jargon, and for them an ontology is
a document or file that fo...
... archaeologists tell
layers apart by playing a game of which-stars-
are-not-like -the- others. The sun and most
other stars swirl around the galactic center
within a thin circular disk. Nearly a ... their convictions. And if you say to either one of them they’re
wrong, then they start tuning you out.” So McNutt tries to make
the 15-year-olds aware of the other’s position and valu...