scientific american - 1993 04 - controlling the quantum jitters of atoms

... critical the aÝected pro- cesses are at the time of their disregula- tion and the ability of the organism ei- ther to compensate for or to repair the damage. If the damage disrupts the reg- ulation of ... through the cavity. The red laser beam traces the line of the in- frared laser used to excite the atoms; the blue beam marks the path of the atoms...

Ngày tải lên: 12/05/2014, 14:49

... people in the U.S. The factor may be associated with about 80 percent of the cases of the ill- ness. IdentiÞcation of the factor, a form of a gene responsible for the manufac- ture of a lipoprotein, ... economic poli- cies: the eÛcient allocation of resourc- es, the fair distribution of resources and the maintenance of a sustainable scale of resource use....

Ngày tải lên: 12/05/2014, 14:50

... ones. Determining the relative ages of the halo and disk reveals much about the sequence of the formation of the gal- axy. On the other hand, it leaves open the question of how old the entire gal- axy actually ... 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 p...

Ngày tải lên: 12/05/2014, 14:48

... together can determine the thick- ness of the ice and the nature of the underlying rock. With Robin E. Bell of the Lamont-Doherty Geological Obser- vatory, the co-leader of ALICE, Blanken- ship ... unsound. Thus, the largest block of problem states is not in the Òrust beltÓ of the North, nor in the high-traÛc re- gions of the Northeast and Southwest, but ra...

Ngày tải lên: 12/05/2014, 14:49

... gam- ma-chain gene were causing the im- munodeficiency. With the further assis- tance of Howard M. Rosenblatt of the Baylor College of Medicine and Alexan- dra H. Filipovich of the University of Minnesota, ... Furthermore, if the hot end of the rod is then plunged into ice, a wave of cooling will follow the wave of heat down the length of the metal. In the...

Ngày tải lên: 12/05/2014, 14:49

... millions of women for more than 20 years beginning in the 1940s to pre- vent miscarriages. Use of the drug end- ed with the discovery that the daugh- ters of DES mothers are unusually like- ly to ... preexist in the fertilized egg. In- stead the code resides in four sets of mini-genes located in widely separated parts of the nucleus. Antibody diversi- ty springs from...

Ngày tải lên: 12/05/2014, 14:50

... colleagues at the Califor- nia Institute of Technology began to ex- amine the chemistry of the atmosphere above Los Angeles. Their work and the research of others have revealed the complexity of atmospheric ... that in almost one Þfth of all the vehicles on the road, the emissions-control equip- ment was either removed by the own- er or damaged by the use of le...

Ngày tải lên: 12/05/2014, 14:50

... each cycle 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 voltage does not change the av- erage ... Kazumi Maki of the Universi- ty of Southern California and by the late John Bardeen of the University of Illi- nois, but it is too early to tell w...

Ngày tải lên: 12/05/2014, 14:54

... 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 ... cautious assessment of the ramifications of the WHO policies: “[They] have increased the awareness among all the players about the com- plexity of the...

Ngày tải lên: 12/05/2014, 15:35

... satel- lite —one of a fleet called the Earth Ob- serving System — uses five state -of- the- art sensors to better diagnose the planet’s health from the sky. 98 92 Copyright 2000 Scientific American, ... glutamate proba- bly owes its popularity to trig- gering the umami taste. Knowl- edge of the structure of the glu- tamate receptor could assist food scientists’ efforts to...

Ngày tải lên: 12/05/2014, 16:02