scientific american - 1995 06 - the world''s strongest magnets

... which of- ten intervene to control the price of their nationÕs cur- rency. In Mexico the central bank maintained the price of the peso within a narrow 36 SCIENTIFIC AMERICAN June 1995 THE ANALYTICAL ... receive the money and send back the change. Tubes re- placed Òcash children,Ó 1 0-, 1 1- and 1 2- year-olds who were exploited to per- form this task. The most el...

Ngày tải lên: 12/05/2014, 15:01

... 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 ... grow the same way that planets do: from the agglomeration of smaller units. The layering of the Milky Way bears that out. On the other hand, cold-dark-matter theories have trouble exp...

Ngày tải lên: 12/05/2014, 16:08

... 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 ... returned to the earth over the low-gain antenna. Tape-search- 50 SCIENTIFIC AMERICAN December 1995 JAILBARS, slices of images taken of the asteroid Ida, were re- t...

Ngày tải lên: 12/05/2014, 15:03

... the impact of urban agriculture con- tinues to broaden, the notion of the gar- den city the turn-of -the- century dream of urban centers lined with trees and or- namental plants —may take on a new ... data from the probe’s 57-min- ute descent did not chal- lenge the prevailing hy- pothesis of the evolution of the solar system and its largest planet, according to Richard Young...

Ngày tải lên: 12/05/2014, 15:08

... of bird-watchers, and they love the birds. And after they watch them, they go home and put up their bug zappers. These birds, even the seed eaters, are feeding heavily on insects when they’re ... traveling the interstate since the wee hours of the morn- ing and what they might say when they arrive at the Capitol and meet with their elected rep- resentatives. Most of his audi- ence...

Ngày tải lên: 12/05/2014, 15:26

... not seem to be the stuff of wild urban legend anymore. Neverthe- less, the rich mythology that has sprung up around the 840-acre island makes it a must-see stop on the con- spiracy theorist’s world ... pain —drugs in the same class as ibuprofen and aspirin. The McGeers, hus- band-and-wife neuroscientists at the Uni- versity of British Columbia, are betting on nonsteroidal anti-i...

Ngày tải lên: 12/05/2014, 16:03

... the wom- en in the rural areas have that same cy- cle, and they teach the same values to their children. They teach their sons to order; they teach their daughters that they must serve even their ... chromosome. To their pleasure, they realized that previous genetic studies had im- plicated roughly the same part of the chro- mosome in SCID. They decided to test the hypothesis that...

Ngày tải lên: 12/05/2014, 14:49

... Scientific American, Inc. SCIENTIFIC AMERICAN June 1994 33 I n 1939 a 33-year-old French mathe- matician proved that a profound conjecture about the behavior dis- played by prime numbers as they ... argue the founders of the Committee for the National Insti- tute for the Environment (CNIE). What is needed, they suggest, is their epony- mous institution. The National Institu...

Ngày tải lên: 12/05/2014, 14:56

... inhibit candor when they are posed the ques- tion, ÒHow big is the diÝerence?Ó (Fur- ther, the work has not yet been peer-re- viewed or published, so the team re- mains quite cautious about the details.) Essentially ... small and medi- um-size businesses. Until the early 1990s, the World Bank ignored the economic signiÞcance of these events or dismissed them as irrel- evant. A...

Ngày tải lên: 12/05/2014, 15:01

... of the organizers is JeÝrey Gold- stein, a psychologist at Adelphi Univer- sity and president of the five-year-old Society for Chaos Theory in Psychology and the Life Sciences. The point of the meeting, ... need to under- stand their relationship with the environment,Ó Gonzalez says. Some of the tribes live in the for- est during the rainy sea- son, some during the dry sea...

Ngày tải lên: 12/05/2014, 15:02