... the delicate bal-
ance among symbionts is destroyed.
SCIENTIFIC AMERICAN January 1993 65
Copyright 1992 Scientific American, Inc.
SCIENTIFIC AMERICAN January 1993 69
tures. Although it appears ... homogeneous.
SCIENTIFIC AMERICAN January 1993 75
IRON ABUNDANCE (SOLAR UNITS)
OXYGEN-TO-IRON RATIO (SOLAR UNITS)
0.010.001 0.1 1.0
4
3
2
1
HALO STARS
OLD DISK STARS
Copyright 1992 Scientific American, ... Chaput; Vice Presi-
dents: Jonathan Piel, John J. Moeling, Jr.
10 SCIENTIFICAMERICAN January 1993
Copyright 1992 Scientific American, Inc.
s a feminist in a family with Victo-
rian mores and...
... zinc-centered
structure devoted to DNA recognition.
62 SCIENTIFICAMERICAN February 1993
Copyright 1993 Scientific American, Inc.
68 SCIENTIFICAMERICAN February 1993
product; cilastatin does not. ... in the number of bases separating the half sites.
64 SCIENTIFICAMERICAN February 1993
Copyright 1993 Scientific American, Inc.
44 SCIENTIFICAMERICAN February 1993
the combined eÝect of environmental
problems ... Bar-
ger; Vice Presidents : Jonathan Piel, John J.
Moeling, Jr.
8 SCIENTIFICAMERICAN February 1993
Copyright 1993 Scientific American, Inc.
three hydrophobic amino acids in vir-
tually identical...
... Bar-
ger ; Vice Presidents: Jonathan Piel, John J.
Moeling, Jr.
8 SCIENTIFICAMERICAN July 1993
PRINTED IN U.S.A.
Copyright 1993 Scientific American, Inc.
repolarize and prepare for Þring anew.
Impulses ...
THRESHOLD
Copyright 1993 Scientific American, Inc.
LETTERS TO THE EDITORS
More Black Hole Paradoxes
I enjoyed ÒBlack Holes and the Cen-
trifugal Force Paradox,Ó by Marek Ar-
tur Abramowicz [SCIENTIFIC AMERICAN,
March], ... workplace and consumer
products.
Second, these oÛcials have often
40 SCIENTIFICAMERICAN July 1993
Copyright 1993 Scientific American, Inc.
...
... think,
Why not? ÑJohn Horgan
38 SCIENTIFICAMERICAN November 1993
Copyright 1993 Scientific American, Inc.
SCIENTIFIC AMERICAN November 1993 73
Copyright 1993 Scientific American, Inc.
glycine receptors, ... I
would have to add that this is true for
African-Americans, Hispanic-Americans,
female Americans, gay Americans, poor
Americans, handicapped Americans and
other oppressed minorities. ÒSociety ... bombers).
Battleship, 1941
Continued on page 76
Copyright 1993 Scientific American, Inc.Copyright 1993 Scientific American, Inc.
12 SCIENTIFICAMERICAN November 1993
50 AND 100 YEARS AGO
0NOVEMBER 1943
ÒAir-conditioning...
... X-RAYS
COMPTON
OBSERVATORY
RADIO
TELESCOPE
OPTICAL TELESCOPE
Copyright 1993 Scientific American, Inc.
18 SCIENTIFICAMERICAN December 1993
hree years ago W. French Ander-
son, then at the National ... safety,Ó Radlick boasts,
Òand we got very good metabolic sup-
32 SCIENTIFICAMERICAN December 1993
Copyright 1993 Scientific American, Inc.
portÑenough to encourage us very
strongly to go into ... a viable and reliable treatment in
its own right. ÑW. Wayt Gibbs
SCIENTIFIC AMERICAN December 1993 33
Copyright 1993 Scientific American, Inc.
razilian lore has it that a red-
haired, human-sized...