scientific american special edition - 2003 vol 13 no1 - the edge of physics

... into the fabric of spacetime. www.sciam.com THE EDGE OF PHYSICS 15 COPYRIGHT 2003 SCIENTIFIC AMERICAN, INC. drew together all the work on T-duality, S-duality and string-string duality under the ... the collision of two three-branes. Thus, branes are no longer the ugly ducklings of string theory. They have tak- en center stage as the microscopic con- stituents...

Ngày tải lên: 12/05/2014, 16:26

... S.A. ul. Garazowa 7 0 2-6 51 Warszawa, POLAND tel: +4 8-0 2 2-6 0 7-7 6-4 0 swiatnauki@proszynski.com.pl Nikkei Science, Inc. 1-9 -5 Otemachi, Chiyoda-ku Tokyo 10 0-8 066, JAPAN tel: +81 3-5 25 5-2 821 Svit Nauky Lviv ... MANAGER 31 0-4 7 7-9 299 fax 31 0-4 7 7-9 179 lcarden@sciam.com SAN FRANCISCO Debra Silver SAN FRANCISCO MANAGER 41 5-4 0 3-9 030 fax 41...

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... Brunet’s of- fice contemplating the seven-million-year-old skull of Sahelan- thropus, the fossil hunter’s quest doesn’t seem quite so unimag- inable. Many of us spend the better part of a lifetime ... HUMAN The jawbones in anamensis and chimpanzees are U-shaped The human jaw widens at the back of the mouth In the tibias of anamensis and humans, the top of the...

Ngày tải lên: 12/05/2014, 16:27

... years. contents 2003 2003 New Light on the Solar System SCIENTIFIC AMERICAN Volume 13 Number 3 C2 SCIENTIFIC AMERICAN 28 4 COPYRIGHT 2003 SCIENTIFIC AMERICAN, INC. 28 SCIENTIFIC AMERICAN Updated from the Fall ... transferred, at least in the relatively recent past, by the eruption of vast plains of basaltic lava and later by the volcanoes that grew on top...

Ngày tải lên: 12/05/2014, 16:27

... would be the derivation of the three-dimensional representation of the world from the two-dimensional signals falling onto the retinas of our two eyes or even onto one of them. Visual theorists ... forms of memory are involved. Is long-term memory need- ed? Some forms of acquired knowledge are so embedded in the machinery of neur- al processing that they are almost c...

Ngày tải lên: 12/05/2014, 16:26

... including the pres- ence or absence of nearby radiation-emitting stars. On the other hand, astronomer David F. Gray of the Univer- sity of Western Ontario in Canada has challenged the existence of the ... geologic features of plan- ets around other stars would require an array of space tele- scopes the size of the U.S. But pictures of Earth do not reveal the pr...

Ngày tải lên: 12/05/2014, 16:23

... ground-based gauges and other TOP -OF -THE- LINE EQUIPMENT: The Doppler radar tower (above) near Washington Dulles Air- port is one of the workhorses intended to increase the accuracy and timeliness of ... from the weather service’s. “More cloudiness, high of 74,” says Abrams in a voice-mail message. “It will be 60 to 70 percent cloudy. A one- or two-out -of- 10 chance for show...

Ngày tải lên: 12/05/2014, 16:25

... nitrogen narcosis in the dark underneath the stern of the wreck of the fa- mous Japanese battleship Naga- to. The 216-meter-long flag- ship of the Imperial Navy dur- ing World War II rests upside down ... on the islands, up to 90 percent of their radi- ation exposure would come from the ce- sium in the local produce. Almost all the rest of their dosage would come...

Ngày tải lên: 12/05/2014, 16:24

... called the U.S. Bur- den of Disease and Injury, by the Harvard School of Pub- lic Health, found a staggering 40-year gap between the longest-lived Americans —Asian -American women—and the shortest, ... promised future bene- fits once the huge baby-boomer genera- tion retires. The basic cause of the shortfall resides in the awesome, glacial pressures of demographics. T...

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... molecular clouds in the nearby part of the Milky Way, the Jeans mass is roughly equal to the mass of the sun, and the masses of the prestellar clumps ob- served in these clouds are about the same. If ... away some of the gas in the collaps- ing clump. But these effects depend strong- ly on the presence of heavy elements in the gas, and therefore they should b...

Ngày tải lên: 12/05/2014, 16:26