scientific american - 1996 01 - the diet - aging connection

... have wondered whether caloric (energy) re- striction per se is responsible for the ad- vantages reaped from low-calorie diets or whether limiting fat or some other component of the diet accounts for the success. ... transform their experiment into the quantum eraser, the researchers tagged one of the photons of the pair (speciÞcally, the one created by the la- serÕs direct...

Ngày tải lên: 12/05/2014, 15:04

... 4,400 12-BILLION-YEAR- OLD AGE TRACK 15-BILLION-YEAR- OLD AGE TRACK NGC 288 NGC 362 Copyright 1992 Scientific American, Inc. means that within the halo the only re- maining main-sequence stars are the extremely ... declines as the reefs get farther away from two centersÑone in the Indo-Pa- ciÞc and the other in the Caribbean. The outlines of a map marking plum- meting dive...

Ngày tải lên: 12/05/2014, 14:48

... Among the most com- mon mines in this group are the Italian scatterable mines TS-50 and SB-33 and the hand-laid VS-50 and VAR-40, the U.S made M14, and the Chinese Type 72. Typically, these weapons ... Space Adminis- tration unveiled the X-36 the first high-performance jet with no tail at all. Remotely controlled and powered by a cruise-mis- sile engine, the 5.4-meter-long, 600-...

Ngày tải lên: 12/05/2014, 15:08

... 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

... users of conven- tional cellular phones. SA MICHAEL GOODMAN Copyright 1996 Scientific American, Inc. The Stellar Dynamo 46 Scientific American August 1996 Copyright 1996 Scientific American, Inc. ... nature show at the Web site whose address the produc- News and Analysis30 Scientific American August 1996 CYBER VIEW The Notworking Computer DAVID SUTER Copyright...

Ngày tải lên: 12/05/2014, 15:14

... protected under the executive order’s “state-of -the- art” tech- nology exemption to the bulk declassi - cation rule. But that introduces another concern. The issue is, what does state- of -the- art technology ... risk factors may affect the expres- sion of the disorder,” the group con- cludes in the Journal of the American Medical Association. The lead author of the s...

Ngày tải lên: 12/05/2014, 15:16

... of the objections. For the mo- ment, then, the theory is ingenious mathe- matics —but of the type that has a long histo- ry of ultimately finding use in real physics. Fractional Success A NEW THEORY ... 2002 SCIENTIFIC AMERICAN Volume 286 Number 1 features 44 Cloned six-cell human embryo www.sciam.com SCIENTIFIC AMERICAN 3 Copyright 2 001 Scientific American, Inc.Copyright...

Ngày tải lên: 12/05/2014, 16:11

... shorter-necked, large-headed plesiosaurs, a group called the pliosauromorphs, were built for high-speed pursuits on the open ocean. The longer-necked, small-headed ple- siosauromorphs, on the other hand, ... and his co-workers at the Universi- ty of Texas at Austin disputed the basic the- ory of negative index materials. They point- ed out that modulation wave fronts (such as th...

Ngày tải lên: 12/05/2014, 16:15

... Utah Copyright 1996 Scientific American, Inc. T he turn-of -the- century stone building is rotting inside, floor- boards dusty and dilapidated, pigeons roosting in the eaves. There are no windows in the moldy ... leishmani- asis is being conducted, and the “pep- tideria,” where the synthesized peptides that form the basis of the malaria vac- cine are stored. He also points out...

Ngày tải lên: 12/05/2014, 15:18

... outside the cell and the other inside. The component outside the cell is the extracellu- lar matrix; the compressive “girders” inside the cell can be ei- ther microtubules or large bundles of cross-linked ... are the com- pression struts, and muscles, tendons and ligaments are the tension-bearing members. At the other end of the scale, pro- teins and other key molecules...

Ngày tải lên: 12/05/2014, 15:33