Thunderstorms: an important mechanism in the transport of air pollutants   总被引：3，自引：0，他引：3  

Dickerson RR  Huffman GJ  Luke WT  Nunnermacker LJ  Pickering KE  Leslie AC  Lindsey CG  Slinn WG  Kelly TJ  Daum PH  Delany AC  Greenberg JP  Zimmerman PR  Boatman JF  Ray JD  Stedman DH 《Science (New York, N.Y.)》1987,235(4787):460-465

Acid deposition and photochemical smog are urban air pollution problems, and they remain localized as long as the sulfur, nitrogen, and hydrocarbon pollutants are confined to the lower troposphere (below about 1-kilometer altitude) where they are short-lived. If, however, the contaminants are rapidly transported to the upper troposphere, then their atmospheric residence times grow and their range of influence expands dramatically. Although this vertical transport ameliorates some of the effects of acid rain by diluting atmospheric acids, it exacerbates global tropospheric ozone production by redistributing the necessary nitrogen catalysts. Results of recent computer simulations suggest that thunderstorms are one means of rapid vertical transport. To test this hypothesis, several research aircraft near a midwestern thunderstrom measured carbon monoxide, hydrocarbons, ozone, and reactive nitrogen compounds. Their concentrations were much greater in the outflow region of the storm, up to 11 kilometers in altitude, than in surrounding air. Trace gas measurements can thus be used to track the motion of air in and around a cloud. Thunderstorms may transform local air pollution problems into regional or global atmospheric chemistry problems.  相似文献   

On the origin of bacterial resistance to penicillin: comparison of a beta-lactamase and a penicillin target   总被引：12，自引：0，他引：12  

J A Kelly  O Dideberg  P Charlier  J P Wery  M Libert  P C Moews  J R Knox  C Duez  C Fraipont  B Joris 《Science (New York, N.Y.)》1986,231(4744):1429-1431

Structural data are now available for comparing a penicillin target enzyme, the D-alanyl-D-alanine-peptidase from Streptomyces R61, with a penicillin-hydrolyzing enzyme, the beta-lactamase from Bacillus licheniformis 749/C. Although the two enzymes have distinct catalytic properties and lack relatedness in their overall amino acid sequences except near the active-site serine, the significant similarity found by x-ray crystallography in the spatial arrangement of the elements of secondary structure provides strong support for earlier hypotheses that beta-lactamases arose from penicillin-sensitive D-alanyl-D-alanine-peptidases involved in bacterial wall peptidoglycan metabolism.  相似文献   

THE SYNTHESIS OF FULL COLORATION IN PHLOX     

Kelly JP 《Science (New York, N.Y.)》1922,55(1418):245-246

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Phytoplankton algae: nutrient concentrations and growth     

Holmes P  Kelly MG  Hornberger GM  O'brien WJ 《Science (New York, N.Y.)》1973,180(4092):1298-1300

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Developmental neurobiology     

Dennis M  Kelly RB 《Science (New York, N.Y.)》1977,195(4278):570

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Correcting the record on the Data Quality Act     

Kelly WG 《Science (New York, N.Y.)》2008,319(5860):158-159

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Detection of uranium from cosmos-1402 in the stratosphere     

Leifer R  Juzdan ZR  Kelly WR  Fassett JD  Eberhardt KR 《Science (New York, N.Y.)》1987,238(4826):512-514

The nuclear reactor from the Soviet radar reconnaissance satellite, Cosmos-1402, reentered the earth's atmosphere on 7 February 1983 and disintegrated over the South Atlantic Ocean. The reactor was powered by approximately 50 kilograms of uranium-235 ((235)U). In an effort to determine the fate of the reactor core, a series of aerosol samples were collected at altitudes between 27 and 36 kilometers in the Northern Hemisphere approximately 1.1 years later by high-altitude balloons. At an altitude of 36 kilometers a 53 +/- 20 percent excess in the (235)U concentration was measured. The total excess of (235)U in the stratosphere was calculated to be 44 +/- 15 kilograms.  相似文献   

Spatial Variability of Turbulent Mixing in the Abyssal Ocean   总被引：3，自引：0，他引：3  

KL Polzin  JM Toole  JR Ledwell  RW Schmitt 《Science (New York, N.Y.)》1997,276(5309):93-96

Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise. The diapycnal diffusivity there was estimated to be less than or approximately equal to 0.1 x 10(-4) meters squared per second. In contrast, mixing rates are large throughout the water column above the rough Mid-Atlantic Ridge, and the diffusivity deduced for the bottom-most 150 meters exceeds 5 x 10(-4) meters squared per second. Such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry.  相似文献   

Prevention of organ allograft rejection by a specific Janus kinase 3 inhibitor     

Changelian PS  Flanagan ME  Ball DJ  Kent CR  Magnuson KS  Martin WH  Rizzuti BJ  Sawyer PS  Perry BD  Brissette WH  McCurdy SP  Kudlacz EM  Conklyn MJ  Elliott EA  Koslov ER  Fisher MB  Strelevitz TJ  Yoon K  Whipple DA  Sun J  Munchhof MJ  Doty JL  Casavant JM  Blumenkopf TA  Hines M  Brown MF  Lillie BM  Subramanyam C  Shang-Poa C  Milici AJ  Beckius GE  Moyer JD  Su C  Woodworth TG  Gaweco AS  Beals CR  Littman BH  Fisher DA  Smith JF  Zagouras P  Magna HA  Saltarelli MJ  Johnson KS  Nelms LF  Des Etages SG  Hayes LS  Kawabata TT 《Science (New York, N.Y.)》2003,302(5646):875-878

Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings.  相似文献   

Women in the Economy: Hidden Aspects of Women's Work     

Kelly MP 《Science (New York, N.Y.)》1988,240(4856):1208-1209

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