Geodynamo Scientific American 200504 1st Edition Scientific American by Scientific American instant download after payment.

I N F O RM A T I O N T E C H N O L O G Y
42 Stopping Spam BY JOSHUA GOODMAN, DAVID HECKERMAN AND ROBERT ROUNTHWAITE
Torrents of junk e-mail threaten to undermine Internet communications, but a combination of techniques might make the problem manageable again.
E A R T H S C I E N C E
50 Probing the Geodynamo BY GARY A . GL ATZMA IER A ND PETER OLSON
Studies of our planet’s churning interior offer intriguing clues to why the earth’s magnetic field occasionally fl ps and when the next reversal may begin.
B I O T E C H N O L O G Y
58 The Alternative Genome BY GIL A ST
Contrary to the old “one gene, one protein” axiom, complex organisms coax more flexibility from their DNA by having small numbers of genes do the work of many.
D E C I S I O N M A K I N G
66 Shaping the Future BY S TEVEN W. POPPER, ROBERT J . LEMPERT AND STEVEN C . BANKES
Given the unavoidable uncertainty of the long-term future, a new analytical approach to setting policy may help with problems such as global warming.
B E H A V I O R A L E C O N O M I C S
72 How Animals Do Business BY FRANS B. M. DE WA AL
Humans and other animals share a heritage of economic tendencies, including cooperation, repayment of favors and resentment of unfair pay.
M A T E R I A L S S C I E N C E
80 Low-Temperature Superconductivity Is Warming Up BY PAUL C . C ANFIELD AND SERGE Y L . BUD’KO
Magnesium diboride is not merely an unexpectedly good superconductor. Properly prepared, it outperforms the materials that are currently industrial favorites.
I N N O V A T I O N
88 A Toxin against Pain BY GARY S TIX
A recently approved analgesic that is a synthetic version of a toxin from a sea snail offers hope for relief from intractable pain.