scientific american - 1995 09 - 150th anniversary issue - key technologies for the 21st century

... Surgeons MICHAEL CRAWFORD Copyright 1995 Scientific American, Inc. 28 SCIENTIFIC AMERICAN September 1995 S queezed by fast-Þx Prozac dis- pensers on one side and stingy insurers on the other, therapists who ... economists can ignore other countries when they make their theo- ries. Large-scale models of the econo- my, fashionable as science back in the 1960s and nowadays still...

Ngày tải lên: 12/05/2014, 15:02

... with the other jumpers to form a complete V-D-J-C gene. This genetic rearrange- ment allows for 4,800 diÝerent vari- eties (100 × 12 × 4 × 1) of heavy chains. The same process occurs in the assem- bly ... the activity of B cells, other T cells and oth- er parts of the immune system. Once formed, cells of both types mi- grate to the spleen, lymph nodes and in- testinal lymphoid...

Ngày tải lên: 12/05/2014, 14:50

... happi- er with the present proposal than they were with the clipper-chip idea. But ac- cording to the administration official, staff-level representatives from the na- tions of the Organization for ... mit.edu/network/pgpfone These Key Words for Hire. The In- ternet is becoming so commercial- ized that even key words the en- tries typed in on search engines—are up for s...

Ngày tải lên: 12/05/2014, 15:15

... hurricane-force winds or earthquakes. Meanwhile the floors tie the inner frame to the outer one, bracing the entire edifice. In the case of the World Trade Center, which was a state-of -the- art design ... MYSTERIOUS FLOW COPYRIGHT 2002 SCIENTIFIC AMERICAN, INC. events that were once in the unformed future into the con- crete but fleeting reality of the present, and thence...

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... pro- posed second-generation system known as Computer-Assisted Passenger Pre-Screening, or CAPPS II. In terms of the variety of in- formation, the sys- tem goes much fur- ther than the 1.0 ver- sion —and ... on the fin- ger. The violence escalated rapidly: subjects increased the force they used by 38 per- cent on each turn. The sci- entists speculate that the subjects underesti...

Ngày tải lên: 12/05/2014, 16:18

... be selected. In the case of I. scapularis, which accounts for most of the Lyme disease in the U.S., the larval form emerges in the summer from eggs de- posited during the spring. It then at- taches ... ROBOTS INHERIT THE EARTH? Marvin Minsky THE SEARCH FOR EXTRATERRESTRIAL LIFE Carl Sagan COMING IN THE OCTOBER ISSUE THE 1994 SINGLE-TOPIC ISSUE LIFE IN THE UNIVERS...

Ngày tải lên: 12/05/2014, 14:58

... Southern California ca- sual appears to rule in MunkÕs oÛce, where the sound of the surf and the smell of the sea relax even the most anx- iety-ridden visitor from the Northeast. Despite the ... rights,Ó Ben Davis reßects. The problem is, muse- ums donÕt see themselves in the art-in- formation business.Ó ÑCorey S. Powell SCIENTIFIC AMERICAN January 1995 31 T hey fit th...

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... elliptic curves. Further, these curves would vio- late certain conditions set forth in an- other famous supposition in number theory, the Taniyama-Shimura conjec- ture. In 1986 Kenneth Ribet of the Uni- versity ... cheek-by-snout with people moving into coastal areas pop- ulated with the ani- malsÕ prized food. Ko- alas prefer to eat the leaves of less than a dozen of the 650 na- ti...

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... CRAWFORD Copyright 1995 Scientific American, Inc. G etting rid of the long-lived, ra- dioactive by-products of nucle- ar power is a problem that has stalked the industry for its 40-year his- toryÑand ... has a preju- dice against obesity.Ó ÑW. Wayt Gibbs SCIENTIFIC AMERICAN March 1995 35 Copyright 1995 Scientific American, Inc. SCIENTIFIC AMERICAN March 1995 37 F o...

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... and thus they began to explore the reasons for the damage to the eggs. The researchers quickly ruled out the possibility that the chemistry of the water where the animals were laying their eggs ... 1996 Scientific American, Inc. stantially diÝerent from those expect- ed. Resolving the discrepancies may be helpful to theoreticians trying to pre- dict the properties of...

Ngày tải lên: 12/05/2014, 15:00