scientific american - 1996 12 - traces of the big bang

... because the power and economy of mass-produced processors are oftencited as factors in the collapse of the supercomputing market. Asmuch cheaper and easier-to-use work-stations based on off -the- shelf ... nuclei. Consequently, the big bang model predicts that aboutone quarter of the mass of the normalmatter of the universe is made of heliumand the other three quarters of hydro-gen. This simple ... formed in the ﬁrst moments of the big bang. Their abundance offers clues to the early evolution of the universe and the nature of cosmic dark matterby Craig J. Hogan68 Scientific American...

scientific american - 2000 12 - rulers of the jurassic seas

... two cen-turies. When dinosaurs such as Iguan-odan grabbed the attention of paleon-tologists in the 1830s, the novelty of the ﬁsh-lizards faded away. Intense in-terest in the rulers of the Jurassic ... most other verte-brates have bones in their eyes.) In the case of ichthyosaurs, the ringpresumably helped to maintain the shape of the eye against the forces of water passing by as the ani-mals ... transistors and other com-ponents onto a single chip. Zhores I.Alferov of the A. F. Ioffe Physico-Tech-nical Institute in St. Petersburg, Rus-sia, and Herbert Kroemer of the Uni-versity of California...

scientific american - 1994 12 - nasa's latest view of the earth

... loners. The families have very diÝerent char-acters, which reßect the person-ality of the matriarch. In the case of Echo, the family is low-key and nonaggressive.How the 50-year-long rela-tionships ... proÞt-able segments of the market. Among the models offered for sale in a givenyear, the more fuel-eÛcient ones tendto be the smaller, slower, bottom -of- the- line vehicles.More fuel-eÛcient ... be re-produced,Ó accordingto the oÛcial pro-gram. A joint produc-tion of the Annals of Improbable Re-search (described by some as the Madmagazine of science) and the M.I.T. Mu-seum, the...

scientific american - 1995 12 - the puzzle of consciousness

... stunningmovie of our watery planet. The spacecraft examined the outerexpanses of the earthÕs magnet-ic Þeld and took the Þrst mea-surements of the moonÕs farside since the days of the Apol-lo program. ... returned to the earthover the low-gain antenna. Tape-search-50 SCIENTIFIC AMERICAN December 1995JAILBARS, slices of images taken of the asteroid Ida, were re-turned to the earth so that the interesting ... dioxide from the air for theirphotosynthesis. At night, the salps re-turn to the depths as much as a kilome-ter below. There they dump the refuse of a dayÕs work: fecal pellets that, Peris-sinotto...

scientific american - 1996 11 - the origins of immunity

... dif-ferent 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 study, the larg-est of ... professor of psychology at the University of Liverpool,and other academics haverufﬂed a few well-groomedfeathers in the staid linguis-tics community. Their gos-sip-grooming hypothesis as-serts ... DOYLECopyright 1996 Scientific American, Inc.News and Analysis36 Scientific American November 1996 these out -of- phase oscillons pull togeth-er into a bound pair or join with othersuch pairs...

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 - 1996 01 - the diet - aging connection

... perennialfear of being held hostage to the suc-cess of their favorite supplier. It dis-tributes, and thereby speeds, the work of adapting software to all the diÝerentbits of hardware used on the Internet.It ... CygnusÕssoftware-for-free, service-for-fee strate-gy could foster innovation. It creates aneasy-to-cross bridge between the aca-demic world and the commercial one.It removes software buyersÕ ... researcherstagged one of the photons of the pair(speciÞcally, the one created by the la-serÕs direct passage through the crys-tal). That way, they knew how the pho-ton was created, which...

scientific american - 1996 05 - the comets' lair

... case. The type of mine, the speciﬁcs of itsoperation, its position on the ground, the position of the victim and the char-acteristics of the environment at the ex-plosion site all affect the ... statusreports. The DOE had no way of know-ing whether the project was on track.Agency managers could not even esti-mate the size of the new system. Never-theless, in September the DOE switchedoff the ... produce injur-ies throughout the body. The size of the wound depends in part on the size of the penetrating splinter. If the victim ismeters away from the site of the explo-sion, the fragments...

scientific american - 1996 06 - the space station

... microorganisms.If 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 ... surprising: they whiparound the planet at upto 200 meters per second.Overall, however, datafrom the probe’s 57-min-ute descent did not chal-lenge the prevailing hy-pothesis of the evolution of the ... itdiverts them from the real sources of advantage in the database world. The ﬁrst and most important of these is the ability to gather new information.Over the long term, the greatest im-pact of computers...

scientific american - 1996 08 - the electronic wallet

... concentration of ozone-de-pleting chemicals in the lower atmo-sphere is falling off fast. Based ontheir calculations, the amount had de-creased some 1 percent by the middle of last year. The decline ... can access the software that willmake them something other than a sili-con-and-plastic paperweight. Larry El-lison of Oracle reckons the low price of an NC will make it a hit in the consumermarket. ... for smart-card intro-duction in the U.S. today is the possibil-ity of multiple uses for the same card. Intheory, the same silicon-imbued piece of plastic could serve as personal identi - cation,...

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