the scientific american book

... published as v 2 of The Scientific American book of mathematical puzzles & diversions New York : Simon and Schuster, 1961 Bibliography: p 1 Mathematical recreations I Scientific American 11 Title ... 1920 The problem and the method of solving i t can be easily extended to networks in the form of the other four Platonic solids The three ways t o number the faces of a n octahedron so t h a t the ... triangles, changing the triangles to rectangles with the given base, then piling the rectangles in a column The column can then be used, by reversing the procedure, for producing any other polygon with

Ngày tải lên: 31/05/2014, 01:31

... point for the random events school Travisano and Lenski and their colleagues then held a rematch in which they adjusted the temperature regime rather than the food The results were broadly the same ... Until the early 1990s, the World Bankignored the economic signiÞcance ofthese events or dismissed them as irrel-evant At the same time, however, thehistorical record did not go unnoticed by the ... made theinteresting discovery that the ring ofSaturn is made up of many small bod-ies, and that the satellites of the inneredge of the ring move more rapidlythan those of the outer edge.” “There

Ngày tải lên: 12/05/2014, 15:01

... in thecenter of the magnet and decreasesmore or less linearly through the 14 lay-ers of the magnet The greatest stress- es, on the other hand, occur in thefourth layer from the center, becausethe ... idea thatthey were the few Cretaceous survivors.The foundation of this theory began to shake in 1981, when fossils of posite birdsĨ were unearthed in Chinaand, then, all over the Northern Hemi-sphere ... out,there is always another shock waiting ex-to push them out of line.ĐPaul Wallich Copyright 1995 Scientific American, Inc. Trang 20working tube systems arrived in the1850s It was then that the

Ngày tải lên: 12/05/2014, 15:01

... Harwood, the beech trees grew on the ice-free shores of arctic islands during the warm Pliocene,and the diatoms thrived in the marinebasins surrounding the landmasses Ant-When the balmy weather of the ... Þnding the genes will helpscientists uncover the biochemistry ofmanic-depression ÒThere are a lot oftheories about neurotransmitters, but at the end of the day, when they Þndthe genes, theyÕre ... N.C The Origin of the Hybrid In their article ÒThe Problematic RedWolf Ó [SCIENTIFIC AMERICAN, July], Rob-ert K Wayne and John L Gittleman pre-sent evidence that strongly supports theidea that the

Ngày tải lên: 12/05/2014, 15:02

... the woman will bearthe genes of another man The longerthe relationship has lasted, the morelikely it is that future children borne bythe woman will also bear the fatherÕsgenes In this case, the ... rates In other words, the fetal strategy is paying oÝ This hypothetical drama is furthercomplicated by the role of the father,whose genetic interests, again, divergefrom those of the mother Conßict ... reinforcing the idea that bees doindeed rush to judgment The researchers discovered that if bees fly to their food, they assume they are awayfrom the hive If they walk to it, they assume they are

Ngày tải lên: 12/05/2014, 15:03

... wave-length of the lightsource divided by the di-ameter of the aperture ofthe objective lens In otherwords, the shorter the wave-lengths and larger the aper-ture, the Þner the resolution.The limit ... The British restored the AmericansÕ belief in the bomb Churchill and Roosevelt agreed to set up a joint research facility in the U.S The British team, including Rotblat, would work with the Americans ... [such as the red wolf ] in the Southeast.Ĩ The question, Streeter con-tends, is whether the animal qualiÞes for protection under the Endangered Species Act, given that it is not, in the opinion

Ngày tải lên: 12/05/2014, 15:04

... throughout the body The size of thewound depends in part on the size ofthe penetrating splinter If the victim ismeters away from the site of the explo-sion, the fragments will frequently pen-etrate the ... withthem There is no supply of the article in that heathen land.” 50, 100 and 150 Years Ago The new talking machine Copyright 1996 Scientific American, Inc Trang 7When the U.S Congresspassed the ... her father’s that have justbeen found and the meadow of Biblicalflowers she would like to create and thebook she is writing about Proust andthe weather “There comes a momentwhen counting the bristles

Ngày tải lên: 12/05/2014, 15:08

... change the Copyright 1996 Scientific American, Inc News and Analysis 34 Scientific American June 1996 then the. .. using high-strength composite materials, they have minimized the ... in the Jovian at- dered whether the thermal... American June 1996 Copyright 1996 Scientific American, Inc plex wordings She notes that many people tend to write less densely as they ... eroded their “cognitive reserve” the smaller the reserve, the earlier the onset... stiffness The wand then picks up the reflected sound and sends the signal to a computer, where it

Ngày tải lên: 12/05/2014, 15:08

... toprove that they were indeed the progen-itors of sperm in the recipient testes Theinvestigators suppressed the immunesystems of the mice so they would notreject the foreign rat tissue These findings, ... surgeons would then direct the pellet through the brain by adjusting the forces of the various mag-nets The pellet could tow a catheter, electrode or other device to minister to the troublesome ... case, the morphogenhas its maximum concentration at thesite of the signal One of the signals controls the opment of the front half of the egg,which gives rise to the head and thorax devel-of the

Ngày tải lên: 12/05/2014, 15:14

... witness the departure of the motor carriages for their race to Brighton, 47 miles The oc-casion of the race was the going into effect of the new law which opens the highways to the use of the motor ... when the oth- er is a crater, they attract If they comewithin 1.4 diameters of each other, Copyright 1996 Scientific American, Inc Trang 14News and Analysis36 Scientific American November 1996 these ... heart Supercritical The Evolution of the Immune System Copyright 1996 Scientific American, Inc Trang 3Scientific American (ISSN 0036-8733), published monthly by Scientific American, Inc., 415

Ngày tải lên: 12/05/2014, 15:16

... no further on the unsuccessful ones.” If the unsatisfying average quality of children’s science books is one problem, their quantity is another The past 12 months brought 700 books for the Morrisons’ ... perhaps they needdolls,” he said afterward “But they shouldn’t share them.”Don Featherstone traveled all the way from Fitchburg,Mass., to receive the Art Ig Featherstone is the creator of thepink ... and others) The program sends the buyer’s encrypted, digitally signed payment via the Internet to the finan-cial institution, which then sends the approval codes back to the merchant Because the

Ngày tải lên: 12/05/2014, 15:18

... ceptor) breaks the links joining the lip-ids to one another, changing the color re-of the film to a reddish magenta The sensitivity of the test scheme islimited mainly by the ability of the hu-man ... preparing the form letter, the op-erator types manually the date and the name and address of the recipient Then a switch is thrown, and the automatic writer takes over, controlled by the previously ... TURTLES GO? Turtles may not be the “living fossils” they were thought to be Trang 14tionable, theories Such was the case inthe 1800s, when the theory of hemato-thermia arose It stated that birds

Ngày tải lên: 12/05/2014, 15:21

... vulnerable to 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 ... nurse theoffspring of other females, they try togive milk primarily to their own cubsand reject the advances of other hungrycubs But they also need sleep Whenthey doze for hours at a time, they ... CUBS ON MOTHERS ON OTHER FEMALES ON MOTHERS ON OTHER FEMALES ON MOTHERS ON OTHER FEMALES WHEN OTHER CUBS ARE ALREADY NURSING WHEN CUB GREETS THE FEMALE NURSING is a job shared by all mothers in

Ngày tải lên: 12/05/2014, 15:23

... these nieces which made them nearly explode with laughter when their mothers read them aloud. All the funny sights in Venice were described, and the stories about the children in India made the ... an umbrella. They called themselves "Knights of the Umbrella and Bundle." The Thoreaus were rather a prominent family in Concord. There were six of them, all told. The father, Mr. John ... needed money and decided to make the colonists pay a tax on tea and a few other things. Then the American colonists were as angry as they could be. They tipped the whole cargo of tea into Boston Harbor,...

Ngày tải lên: 18/02/2014, 08:20

... knowledge of the location and altitude at which the device is explod - ed, and the local meteorology—particu - larly a three-dimensional characteriza - tion of the wind field in the vicinity of the ... when the fireball from the explosion cools sufficiently to lose buoyancy. HOOD was the largest atmospheric test conducted at the Nevada Test Site (and in the continental U.S.). Fortunately, the ... California, at the same time, the corresponding values would have been 0.003, 0.01, and 0.0004 Gy. (A link to these data is available in the bibliography.) Following the publication of the NCI findings...

Ngày tải lên: 15/03/2014, 01:20

... the book you’re reading. So where’s the confusion? The book was about a writer in his fifties working on a book. In the future the book has yet to be written, even if it was written in the ... what they did they were a part of history: they belonged to the United States government. But now they were sitting on the throne of God, the only being higher than the president of the United ... something that was the beginning of the end of the world. Throughout my life I often felt like I was living in a shell of the better past. The sixties, the Beat Generation, the Lost Generation,...

Ngày tải lên: 15/03/2014, 06:20

... 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 ... tissue, the antibody blocked the attachment of the lymphocytes to high endothelial venules SCIENTIFIC AMERICAN January 1993 87 cells. The L-selectins, or homing receptors, on lymphocytes determine the ... has attached to the endothelium, it can migrate out of the blood vessel. Copyright 1992 Scientific American, Inc. 66 SCIENTIFIC AMERICAN January 1993 The corals lose algae, leaving their tis- sues so...

Ngày tải lên: 12/05/2014, 14:48

... determine the tension in the spring. The tension, in turn, equals the sum of the two forces acting on the weight: the gravitational force and the centrifugal force. To measure either one of these ... gravitational Þeld of the black hole (that is, the rays were straight), the lamp would disappear behind the left part of the tube, and Alice would conclude that the tube was bent to the left. If the light ... change the orientation of their spaceships as they orbit the black hole; both pilots must rotate their spacecraft so that the stretched spring always points toward a mark on the hull. The direction...

Ngày tải lên: 12/05/2014, 14:49

... microkelvins. In the process the coldest atoms mi- grate to the center of the trap, whereas the hotter atoms oscillate from one side to the other. The hot atoms at the sides of the trap can be ... ). They drop their colors and sneak into another maleÕs nest, inseminating the eggs present there. a b c d Copyright 1993 Scientific American, Inc. the metal. The strong electric Þeld at the ... survival, they may suÝer longer from the nonfatal but highly disabling illnesses associated with old age. SCIENTIFIC AMERICAN April 1993 51 Copyright 1993 Scientific American, Inc. 82 SCIENTIFIC AMERICAN...

Ngày tải lên: 12/05/2014, 14:49

... demon- strated in the laboratory. The EPR phenomenon is the linchpin of quantum teleportation. Alice takes one of the EPR photons and gives the other to Bob. Bob then moves to an- other location with the photon. ... 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 same way, temperature ßuctua- tions at the ... throughout the length of the cilium. In addition, an extra pair of mi- crotubules not found in the centriole develops along the axis. The structure of the axoneme mirrors the ninefold symmetry of the...

Ngày tải lên: 12/05/2014, 14:49