摘要:

Brain gain and abundant funds for infrastructure are signs of a far rosier research climate than Canada could boast a few years ago. Key to the about‐face are the country's overall budget—Canada is the only G8 country with a surplus—and its goals of doubling the number of graduate students and moving from the world's 15th to 5th biggest R&D spender per capita by 2010. Physics, along with other fields in the sciences and humanities, is benefiting from the new money being injected into research.

ISSN:0031-9228    

DOI:10.1063/1.1583526

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The Department of Defense has asked Congress to abolish the Spratt–Furse provision, a nine‐year‐old ban on developing new nuclear weapons below 5‐kiloton yields. Meanwhile, the Air Force has made a bid for more funding for a separate, new high‐yield nuclear weapon to destroy deeply buried, hardened bunkers. The requests are part of the Bush administration's 2004 budget proposal (see the story on page 30). The development of tactical nuclear weapons—high‐ or low‐yield—and the recent mandate that the US Strategic Command take charge of the full range of warfare options for combating foreign weapons of mass destruction increase the likelihood that nuclear weapons will be used, say critics.

ISSN:0031-9228    

DOI:10.1063/1.1583527

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

John Bahcall has won $1 million. A theorist at the Institute for Advanced Study in Princeton, New Jersey, Bahcall is being honored with a Dan David prize for his wide‐ranging contributions to astrophysics, from the interpretation of quasar absorption lines, to the first detection of a neutron star companion, to his calculations on solar neutrinos, which predicted a flux roughly three times greater than that observed on Earth. The shortfall in solar neutrinos is now thought to be caused by neutrino oscillations (see PHYSICSTODAY, December 2002, page 16).

ISSN:0031-9228    

DOI:10.1063/1.1583529

出版商:AIP    

年代:1903

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.2409968

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

When the Bush administration unveiled its budget proposal last year, its first stated priority was “defeating terrorism abroad,” and the second was “protecting the homeland.” Accordingly, money flowed to the Department of Defense and to programs that would eventually become part of the newly forming Department of Homeland Security. All agencies, including those that supported science, were directed to shape their funding based on national security, an Office of Management and Budget official said bluntly.

ISSN:0031-9228    

DOI:10.1063/1.1583531

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

“The noise is the signal” was a saying of Rolf Landauer, one of the founding fathers of mesoscopic physics. What he meant was that fluctuations in time of a measurement can be a source of information that is not present in the time‐averaged value. As figure 1 reminds us, some types of noise are more interesting than others. A physicist with access to sensitive ways of distinguishing the granularity in a signal may delight in the noise.

ISSN:0031-9228    

DOI:10.1063/1.1583532

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Imagine molecular gears that oscillate against each other as they are stimulated by the addition or removal of a single electron, or a domino‐like arrangement of molecules in which a small perturbation on one end initiates a molecular‐mechanical cascade that ripples through the whole assembly in a predetermined fashion. Imagine a wire in which the presence or absence of a single atom dominates the electrical conductivity, or in which a biomolecular recognition process is used to open up new conductivity pathways. These descriptions are respectively those of a molecular‐mechanical switch that forms the basis of a random access memory circuit, a molecular‐based three‐input mechanical Boolean sorter, a single‐molecule electrically or magnetically gated switch, and a single‐stranded DNA wire that is “turned on” by hybridization of the DNA into the double‐stranded form. These molecular systems, and a host of other equally diverse chemical species, are principal actors in the rapidly emerging field of molecular electronics.

ISSN:0031-9228    

DOI:10.1063/1.1583533

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Did you know that elephant vocal sounds occur at about 400 Hz and can't be heard by humans? The caretaker at your local zoo didn't either. But your children may have been taught that tidbit if their science class used one of the most popular middle‐school physical science texts. I learned of the elephant blunder and many other problems with the content and presentation of texts used in grades 6 through 9 as part of an ongoing project that began in 1998, when I received a grant from the David and Lucile Packard Foundation.

ISSN:0031-9228    

DOI:10.1063/1.1583534

出版商:AIP    

年代:1903

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1583535

出版商:AIP    

年代:1903

数据来源: AIP

ISSN:0031-9228    

DOI:10.1063/1.1583536

出版商:AIP    

年代:1903

数据来源: AIP