scientific american - 1997 12 - building the biggest

... the status of fish, with the southern half of the country having far more imper- iled species than the northern half; the large map below shows the number at risk in the 2,111 watersheds of the ... which they originally resid- ed. Instead they flow rather freely be- tween the atoms and are said to be de- localized. But they stay in or around the cluster because they are att...

Ngày tải lên: 12/05/2014, 15:32

... help prevent the cell-to-cell spread of any HIV particles that somehow survived the HIV-destroying therapy. The idea of simultaneously curing pa- In Search of AIDS-Resistance Genes50 Scientific American ... sophisticated Neander- thal: they buried their dead, made sym- bolic objects and adorned their bodies. And if they were playing musical instru- News and Analysis28 Scientific...

Ngày tải lên: 12/05/2014, 15:29

... conclusion. De- spite the hype surround- ing the Þeld, the experts wrote, Òthere is a substan- tial gap between the tech- nology that is available and the technology that is needed to realize the po- tential ... 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 nonaggress...

Ngày tải lên: 12/05/2014, 14:59

... planet. The spacecraft examined the outer expanses of the earthÕs magnet- ic Þeld and took the Þrst mea- surements of the moonÕs far side since the days of the Apol- lo program. These images re- vealed ... first slide the trousers off onto the rope, then push one leg through the other. The outside leg is reversed twice in the process, leaving the trousers on the ro...

Ngày tải lên: 12/05/2014, 15:03

... Utah Copyright 1996 Scientific American, Inc. T he turn-of -the- century stone building is rotting inside, floor- boards dusty and dilapidated, pigeons roosting in the eaves. There are no windows in the moldy ... leishmani- asis is being conducted, and the “pep- tideria,” where the synthesized peptides that form the basis of the malaria vac- cine are stored. He also points out...

Ngày tải lên: 12/05/2014, 15:18

... polydiacety- lene film, which happens to be blue. But the binding of E. coli toxin to the other part of the molecule (the cell-surface re- ceptor) breaks the links joining the lip- ids to one another, ... the way from the sun’s in- terior to the earth and out to the farthest reaches of the solar wind. Some of its in- struments are now poised to resolve sev- eral other myst...

Ngày tải lên: 12/05/2014, 15:21

... preda- tors. Once the cubs can move, though, the mothers bring them out into the open to join the rest of the pride. If any of the other females have cubs, they form a crèche and remain in near-con- stant ... to them, some home owners will balk at the idea of selling their excess electricity at a dis- count to the local utility, which then re- sells the power for several tim...

Ngày tải lên: 12/05/2014, 15:23

... of bird-watchers, and they love the birds. And after they watch them, they go home and put up their bug zappers. These birds, even the seed eaters, are feeding heavily on insects when they’re ... CRAWFORD Copyright 1997 Scientific American, Inc. News and Analysis Scientific American June 1997 31 But the videotapes revealed that dis- satisfied females rarely assume the prop-...

Ngày tải lên: 12/05/2014, 15:26

... Copyright 1997 Scientific American, Inc. News and Analysis32 Scientific American October 1997 So last summer the group experiment- ed with the two structures, first on computer models, then on the real ... and Analysis52 Scientific American October 1997 CYBER VIEW Master of Your Domain DAVID SUTER 54 Scientific American October 1997 W hen the first issue of Scien...

Ngày tải lên: 12/05/2014, 15:30

... SERVER CLUS- TER . These men are the defense the Blue Team in this high-tech version of capture the flag —and they lean back in their chairs confidently. This past March, they claim, their “agents” —computer ... 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...

Ngày tải lên: 12/05/2014, 16:06