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 themselves. When in use, the entire appa-ratus ... stable, the highbirth rates of the baby boom postponed the aging of the population by widen-ing the base of the age structure again.As the baby boomers grow older, how-ever, the average age of the...

scientific american - 1993 11 - reading the genes of extinct species

... people in the U.S. The factor may be associated withabout 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. The Þrst two are tradi- SCIENTIFIC AMERICAN ... in which the disease was inher-ited along with the section of chromo-28 SCIENTIFIC AMERICAN November 1993 cause damage or whether blame belongsto the chemicals they carry deep into the lungs.Many...

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scientific american - 1993 01 - the turbulent birth of the milky way

... 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 awayfrom 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 of lower ... 50percent of its former level.The extent of bleaching, environ-mental tolerances and the life-his-tory characteristics of the domi-nant corals determine whether a reef re-covers from the loss of...

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scientific american - 1993 03 - black holes and the centrifugal force paradox

... 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 rather in the southeastern U.S. ... hole. The stationis a circular tube centered exactly on the path of the circular ray so that the axis of the tube and the path of the ray coincide. The astronauts know that the axis of the tube...

scientific american - 1993 06 - tuning in the radio signals of ancient galaxies

... 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 hotend 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 same way, temperature ßuctua-tions at the ... factors; G-blocks do not.Ó The workers were able to improve the biocompatibility of the capsules byincreasing the ratio of G-blocks to M-blocks. To counteract the eÝects of re-sidual M-blocks...

scientific american - 1993 09 - special issue - life, death, and the immune system

... millions of women for more than 20years 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 separatedparts of the nucleus. Antibody diversi-ty springs from the size of these mini-gene ... aÛnity.During the development of an anti-body-forming cell, one member fromeach set of mini-genes jumps out of itsoriginal position and links with the other jumpers to form a complete V-D-J-C gene....

scientific american - 1993 10 - is los angeles winning the war on smog

... colleagues at the Califor-nia Institute of Technology began to ex-amine the chemistry of the atmosphereabove Los Angeles. Their work and the research of others have revealed the complexity of atmospheric ... thatin 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 leaded fu-els. The latter problem has abated ... contributes 26 percent of the hydrocarbons, 18 percent of the nitro-gen oxides and 30 percent of the sulfuroxides and smaller percentages of oth-er pollutants. The remainder of the pol-lutants are...

scientific american - 1994 04 - the dilemmas of prostate cancer

... eachcycle of the AC Þeld. When the marbleis 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 lateJohn Bardeen of the University of Illi-nois, but it is too early to tell whethertheir model applies to our low-tempera-ture ... model slight-ly. Self-organization comes from self-interactions, so our model has to in-clude the push-and-pull between the diÝerent regions of the CDW. One mar-ble at the center of mass is...

scientific american - 1998 04 - the unwired world

... andapplied 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 awarenessamong all the players about the com-plexity of the donations process.”There is one more complication ... oscillations. Swordy, a profes-sor at the University of Chicago, re-ceived his Ph.D. from the University of Bristol in 1979. He was a member of the team of investigators for the Cos-mic Ray Nuclei...

scientific american - 2000 04 - quantum teleportation

... satel-lite—one of a ﬂeetcalled the Earth Ob-serving System—uses ﬁve state -of- the- art sensors tobetter diagnose the planet’s healthfrom the sky.9892Copyright 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 assistfood scientists’ efforts to modi-fy the tastes of various ... asif the laws of the small and the laws of the large are in conﬂict with each other,”Greene says. It has been modern physics’embarrassing secret. The fact that the two theories don’t ﬁt together...

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