Optical properties of the South pole ice at depths between 0.8 and 1 kilometer     

Askebjer P  Barwick SW  Bergström L  Bouchta A  Carius S  Coulthard A  Engel K  Erlandsson B  Goobar A  Gray L  Hallgren A  Halzen F  Hulth PO  Jacobsen J  Johansson S  Kandhadai V  Liubarsky I  Lowder D  Miller T  Mock PC  Morse R  Porrata R  Price PB  Richards A  Rubinstein H  Schneider E  Sun Q  Tilav S  Walck C  Yodh G 《Science (New York, N.Y.)》1995,267(5201):1147-1150

The optical properties of the ice at the geographical South Pole have been investigated at depths between 0.8 and 1 kilometer. The absorption and scattering lengths of visible light ( approximately 515 nanometers) have been measured in situ with the use of the laser calibration setup of the Antarctic Muon and Neutrino Detector Array (AMANDA) neutrino detector. The ice is intrinsically extremely transparent. The measured absorption length is 59 +/- 3 meters, comparable with the quality of the ultrapure water used in the Irvine-Michigan-Brookhaven and Kamiokande proton-decay and neutrino experiments and more than twice as long as the best value reported for laboratory ice. Because of a residual density of air bubbles at these depths, the trajectories of photons in the medium are randomized. If the bubbles are assumed to be smooth and spherical, the average distance between collisions at a depth of 1 kilometer is about 25 centimeters. The measured inverse scattering length on bubbles decreases linearly with increasing depth in the volume of ice investigated.  相似文献   

Carbon in Amazon forests: unexpected seasonal fluxes and disturbance-induced losses   总被引：1，自引：0，他引：1  

Saleska SR  Miller SD  Matross DM  Goulden ML  Wofsy SC  da Rocha HR  de Camargo PB  Crill P  Daube BC  de Freitas HC  Hutyra L  Keller M  Kirchhoff V  Menton M  Munger JW  Pyle EH  Rice AH  Silva H 《Science (New York, N.Y.)》2003,302(5650):1554-1557

The net ecosystem exchange of carbon dioxide was measured by eddy covariance methods for 3 years in two old-growth forest sites near Santarém, Brazil. Carbon was lost in the wet season and gained in the dry season, which was opposite to the seasonal cycles of both tree growth and model predictions. The 3-year average carbon loss was 1.3 (confidence interval: 0.0 to 2.0) megagrams of carbon per hectare per year. Biometric observations confirmed the net loss but imply that it is a transient effect of recent disturbance superimposed on long-term balance. Given that episodic disturbances are characteristic of old-growth forests, it is likely that carbon sequestration is lower than has been inferred from recent eddy covariance studies at undisturbed sites.  相似文献   

Social psychology. Using the psychology of evil to do good     

Miller G 《Science (New York, N.Y.)》2011,332(6029):530-532

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Integrase inhibitors and cellular immunity suppress retroviral replication in rhesus macaques     

Hazuda DJ  Young SD  Guare JP  Anthony NJ  Gomez RP  Wai JS  Vacca JP  Handt L  Motzel SL  Klein HJ  Dornadula G  Danovich RM  Witmer MV  Wilson KA  Tussey L  Schleif WA  Gabryelski LS  Jin L  Miller MD  Casimiro DR  Emini EA  Shiver JW 《Science (New York, N.Y.)》2004,305(5683):528-532

We describe the efficacy of L-870812, an inhibitor of HIV-1 and SIV integrase, in rhesus macaques infected with the simian-human immunodeficiency virus (SHIV) 89.6P. When initiated before CD4 cell depletion, L-870812 therapy mediated a sustained suppression of viremia, preserving CD4 levels and permitting the induction of virus-specific cellular immunity. L-870812 was also active in chronic infection; however, the magnitude and durability of the effect varied in conjunction with the pretreatment immune response and viral load. These studies demonstrate integrase inhibitor activity in vivo and suggest that cellular immunity facilitates chemotherapeutic efficacy in retroviral infections.  相似文献   

Wind velocities on venus: vector determination by radio interferometry     

Counselman CC  Gourevitch SA  King RW  Pettengill GH  Prinn RG  Shapiro II  Miller RB  Smith JR  Ramos R  Liebrecht P 《Science (New York, N.Y.)》1979,203(4382):805-806

To determine the wind directions and speeds on Venus, as each Pioneer probe fell to the surface we tracked its motion in three dimensions using a combination of Doppler and long-baseline radio interferometric methods. Preliminary results from this tracking, coupled with results from test observations of other spacecraft, enable us to estimate the uncertainties of our eventual determinations of the velocity vectors of the probes with respect to Venus. For altitudes below about 65 kilometers and with time-averaging over 100-second intervals, all three components of the velocity should have errors of the order of 0.3 meter per second or less.  相似文献   

Inhibitors of strand transfer that prevent integration and inhibit HIV-1 replication in cells     

Hazuda DJ  Felock P  Witmer M  Wolfe A  Stillmock K  Grobler JA  Espeseth A  Gabryelski L  Schleif W  Blau C  Miller MD 《Science (New York, N.Y.)》2000,287(5453):646-650

Integrase is essential for human immunodeficiency virus-type 1 (HIV-1) replication; however, potent inhibition of the isolated enzyme in biochemical assays has not readily translated into antiviral activity in a manner consistent with inhibition of integration. In this report, we describe diketo acid inhibitors of HIV-1 integrase that manifest antiviral activity as a consequence of their effect on integration. The antiviral activity of these compounds is due exclusively to inhibition of one of the two catalytic functions of integrase, strand transfer.  相似文献   

Electron microscopic autoradiography of rabbit reticulocytes active and inactive in protein synthesis     

A Miller  A B Maunsbach 《Science (New York, N.Y.)》1966,151(713):1000-1001

Electron microscopic autoradiography indicates that only a fraction of ribosome-containing reticulocytes (from phenylhydrazine-treated rabbits) is capable of active protein synthesis in vitro. Ribosomes, and, indeed, polyribosomes, do not appear to limit the rate of protein synthesis.  相似文献   

APPLICATION OF N15 TO THE STUDY OF BIOLOGICAL NITROGEN FIXATION     

Burris RH  Miller CE 《Science (New York, N.Y.)》1941,93(2405):114-115

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Evolutionary and biomedical insights from the rhesus macaque genome   总被引：1，自引：0，他引：1  

Rhesus Macaque Genome Sequencing  Analysis Consortium  Gibbs RA  Rogers J  Katze MG  Bumgarner R  Weinstock GM  Mardis ER  Remington KA  Strausberg RL  Venter JC  Wilson RK  Batzer MA  Bustamante CD  Eichler EE  Hahn MW  Hardison RC  Makova KD  Miller W  Milosavljevic A  Palermo RE  Siepel A  Sikela JM  Attaway T  Bell S  Bernard KE  Buhay CJ  Chandrabose MN  Dao M  Davis C  Delehaunty KD  Ding Y  Dinh HH  Dugan-Rocha S  Fulton LA  Gabisi RA  Garner TT  Godfrey J  Hawes AC  Hernandez J  Hines S  Holder M  Hume J  Jhangiani SN 《Science (New York, N.Y.)》2007,316(5822):222-234

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INCOMES OF COLLEGE GRADUATES TEN AND FIFTEEN YEARS AFTER GRADUATION     

Miller HA 《Science (New York, N.Y.)》1914,40(1031):484-485

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