ISSN:0031-9228    

DOI:10.1063/1.2408496

出版商:AIP    

年代:1902

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1522151

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Localizing sounds and making sense of our acoustic surroundings from the sounds that our ears register are essential but complicated tasks. The brains of humans and other animals exploit a number of cues to meet these challenges (see “How We Localize Sound,” by William Hartmann in PHYSICSTODAY, November 1999, page 24).

ISSN:0031-9228    

DOI:10.1063/1.1522153

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

The information age has been facilitated by the exponentially growing capacity of such storage media as magnetic disks. As demand has soared, the information‐storage industry has crammed more and more bits into ever shrinking areas. Significant innovations have already pushed magnetic storage densities well beyond the limits forecast by pundits just a few years ago. Developments now on the horizon promise to raise the densities from values of 30‐50 gigabits per square inch(Gb/in2),which are typical today, to double or triple those values in the near future, and eventually to densities as high as 1 terabit (Tb) per square inch. (See the box on page 16.)

ISSN:0031-9228    

DOI:10.1063/1.1522154

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Axial rotation causes Earth to protrude slightly at its midsection. While scientists have long known the magnitude of Earth's oblateness, only since the 1970s have they been able to monitor minute changes in it, thanks to the global view provided by satellites. Such changes in the equatorial bulge reflect large‐scale redistributions of mass. For example, the satellite measurements can detect such small effects as the seasonal movements of air masses in the atmosphere and the transport of water among oceans, atmosphere, and land.

ISSN:0031-9228    

DOI:10.1063/1.1522155

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Crazy people go into mineshafts to see stars during the day, says University of Athens physicist Leonidas Resvanis, quoting the first‐century Roman naturalist Pliny the Elder. As Resvanis sees it, overcoming background light by peering at the sky from a hole in the ground was the forerunner to projects like the one he heads, the Neutrino Extended Submarine Telescope with Oceanographic Research. NESTOR is a detector designed to sit near the bottom of the Mediterranean Sea and monitor the heavens for neutrinos. In a report released this summer, the High Energy Neutrino Astrophysics Panel (HENAP), which was set up by the International Union of Pure and Applied Physics, gives its stamp of approval to stepping up such research and, specifically, to building a cubic‐kilometer‐scale neutrino detector deep under water in the Northern Hemisphere.

ISSN:0031-9228    

DOI:10.1063/1.1522156

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Noting that “our terrorist enemies are technically savvy,” the President's Council of Advisors on Science and Technology has written a report urging the administration to significantly elevate the role of science and technology (S&T) in the new Department of Homeland Security (DHS). The report, endorsed in late July by Office of Science and Technology Policy (OSTP) Director John Marburger, says the administration and Congress should “give careful attention to the research and development and technological functions of the new department. Decisions made now will affect the nation's long‐term technological leadership in the antiterrorism effort.”

ISSN:0031-9228    

DOI:10.1063/1.1522157

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

There may be no better‐known lines of least poetry than these, at least among physicists, thanks to Murray Gell‐Mann's having dubbed the elementary constituents of matter “quarks.” Gell‐Mann had come up with the sound “kwork,” but then adopted the spelling in James Joyce'sFinnegans Wake, partly because “the number three fitted perfectly the way quarks occur in nature,” as Gell‐Mann writes inThe Quark and the Jaguar: Adventures in the Simple and the Complex(W.H. Freeman, 1994).

ISSN:0031-9228    

DOI:10.1063/1.1522159

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Welcoming students from 70 countries, Indonesian President Megawati Sukarnoputri kicked off the 33rd International Physics Olympiad in Nusa Dua, Bali, in July, by saying that the event “can be a positive means for increasing people's attention, understanding, and mastery of basic science.” Her comments marked the first time the event has been opened by a head of state.

ISSN:0031-9228    

DOI:10.1063/1.1522160

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

The National Academy of Sciences has issued a report concluding that the “main technical concerns raised about the Comprehensive Nuclear Test Ban Treaty (CTBT)… are all manageable.”Technical Issues Related to the Comprehensive Nuclear Test Ban Treatywas written over a two‐year period by 11 members of the NAS committee on international security and arms control. The panel of scientists, arms control experts, and former national laboratory and industry executives was chaired by John Holdren of Harvard University. The report concludes that “verification capabilities for the treaty are better than generally supposed, adversaries could not significantly advance their nuclear weapons capabilities through tests below the threshold of detection, and the United States has the technical capabilities to maintain confidence in the safety and reliability of its existing weapons stockpile without periodic tests.” The State Department is currently evaluating the report, which is available at http://www.nap.edu/html/ctbt.

ISSN:0031-9228    

DOI:10.1063/1.1522161

出版商:AIP    

年代:1902

数据来源: AIP