scientific american - 1998 01 - flying over the solar system
scientific american - 1998 01 - flying over the solar system
... of a tiny needle. They also tested the glucose levels in these volunteers by the finger-stick method. They found that both the skin-fluid sample and the fin- ger-stick measured the correct glucose levels ... 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 micr...
Ngày tải lên: 12/05/2014, 15:33
scientific american - 1998 02 - wrapping up the universe
... the thigh was shorter than the shin, and the fibula, the bone to the side of the shinbone, was re- The Origin of Birds and Their Flight Scientific American February 1998 43 Bones of Contention A lthough ... bats, the hand part of the wing generates the thrust, and the rest of the wing provides the lift. Jeremy M. V. Rayner of the University of Bristol showed i...
Ngày tải lên: 12/05/2014, 15:33
scientific american - 1998 11 - greenland's mysterious meteor - fire over the ice
... Scotland rees- tablished contact with the craft about 25 hours after they last heard from it, they reenacted one of those Tranquilli- ty-base-here -the- Eagle-has-landed, NASA-flight-control jubilation ... (photo- graph at right). Near the center of the glow, where the solar reflection is most intense, the slicks look espe- cially bright. But at the periphery of the sun-glint...
Ngày tải lên: 12/05/2014, 15:48
scientific american - 1993 01 - the turbulent birth of the milky way
... 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 diversity coincide with the con- tours ... around the world in the latitudes that general- ly fall between the southern tip of Flori- da and mid-Australia. They rank among the most biologically productive of all marine...
Ngày tải lên: 12/05/2014, 14:48
scientific american - 1996 01 - the diet - aging connection
... like the one about the Ro- man galley slaves who get extra food rations because the captain wants to go waterskiing: ¥ According to the air force, the phaseout cut the use of ozone-bust- ing CFC-113 ... OGDEN Copyright 1995 Scientific American, Inc. SCIENTIFIC AMERICAN January 1996 31 easily destroyed. Moreover, some theo- rists raised certain technical objec- tions, namely...
Ngày tải lên: 12/05/2014, 15:04
scientific american - 1998 04 - the unwired world
... and applied them to the time-honored tech- nology of fuel cells. The key was in the packaging. Whereas most fuel-cell re- searchers start with the design of the electrolyte and electrodes, Hockaday re- alized ... in- fects more than 95 percent of the motor neurons in the spinal cord and many other cells in the brain. The infected cells either overcome the virus or die. Th...
Ngày tải lên: 12/05/2014, 15:35
scientific american - 2002 01 - the first human clone
... 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 ... Prize in Physics for devising the original theory of the two- dimensional fractional quantum Hall effect, the discovery of the four-dimensional quan- tum Hall state is rather be...
Ngày tải lên: 12/05/2014, 16:11
scientific american - 2003 01 - the nanodrive
... collision, the South Pole–Aitken Basin is a 13-kilometer- deep gouge into the lunar crust that may ex- pose the moon’s mantle. It is the largest im- pact crater in the entire solar system. Thanks ... 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- siosau...
Ngày tải lên: 12/05/2014, 16:15
scientific american special edition - 2003 vol 13 no3 - new light on the solar system
... 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 1998 issue of Scientific ... cloud cover. The high- er reflectivity reduces the incoming solar en- ergy and hence the temperature. This neg- ative feedback acts as a thermostat, keeping t...
Ngày tải lên: 12/05/2014, 16:27
scientific american - 1993 06 - tuning in the radio signals of ancient galaxies
... 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 ... Moreover, the depth at which the measured proÞle departs from the undisturbed geothermal gra- dient is related to the time that climat- ic change began. The details of the pro-...
Ngày tải lên: 12/05/2014, 14:49