scientific american - 2003 01 - the nanodrive

... 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

... 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

... 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 passage through the crys- tal). That ... developed coun- tries, many of which are strug- gling to electrify. The panel, as- sembled by the American Nuclear Society, also chided the U.S. gov- ernment for halting it...

Ngày tải lên: 12/05/2014, 15:04

... 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

... 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

... development,” the au- thors wrote in the winter-spring issue of Law and Con- temporary Problems. (Their other article on the Bayh- Dole Act appeared in the January-February issue of American Scientist.) Rai ... more of the craft’s mass to the all-important ther- mal shield. After descending to the lower at- mosphere, the capsule could float on para- chutes to an ocean landing...

Ngày tải lên: 12/05/2014, 16:16

... of the nuclei then spin in opposi- tion to the external Þeld in high-energy orientations. The process is adiabatic, meaning the entropy remains un- changed. The resulting spin distribution is the ... 2,3,7,8-tetrachlo- rodibenzo-para-dioxin, the most potent of the 75 types of dioxinÑbinds to an intracellular receptor. The dioxin-laden receptor then joins with a transporter t...

Ngày tải lên: 12/05/2014, 14:50

... powers can help them rise to the top. Since then, the Morrises and Alexan- der have had a falling-out, with each side accusing the other of hogging cred- it for the concept of nonlethality. ÒAlex- ander ... of the AC Þeld. When the marble is hopping down the egg tray with the help of the AC Þeld, augmenting the av- erage tilt of the egg tray by increasing the DC voltag...

Ngày tải lên: 12/05/2014, 14:54

... stream. $500.00 $100.00 $50.00 $100.00 $500.00 $400.00 $450.00 $350.00 DEPOSIT CHECK#314 DEPOSIT CHECK#315 4/5/94 4/26/94 4/27/94 11/3/94 011 111000000 0010 1010 1000000 0010 00 0011 1 1011 10BITSTREAM: UNINTENDED 5-BIT KEY (VALUE OF 011 11=15) INTENDED 4-BIT KEY (VALUE OF 011 1=7) UNINTENDED 15-BIT DATA BYTE INTENDED 7-BIT DATA BYTES LAURIE ... ca- sual appears to rule in MunkÕs oÛce, wh...

Ngày tải lên: 12/05/2014, 15:00

... that they were the few Cretaceous survivors. The foundation of this theory began to shake in 1981, when fossils of Òop- posite birdsÓ were unearthed in China and, then, all over the Northern Hemi- sphere. ... and lead to the hy- poactivity seen there during clinical de- pression. If he is right, the theory would explain the gender gap, at least in part. Others at the NIMH have m...

Ngày tải lên: 12/05/2014, 15:01