Polypeptide composition of fraction 1 protein from parasexual hybrid plants in the genus Nicotiana     

Kung SD  Gray JC  Wildman SG  Carlson PS 《Science (New York, N.Y.)》1975,187(4174):353-355

Analysis of the subunit polypeptide composition of Fraction 1 proteins gives information on the expression of both nuclear and chloroplast genomes; the large subunits of the protein are coded by chloroplast DNA, whereas the small subunits are coded by nuclear DNA. Fraction 1 protein isolated from the leaves of parasexual hybrid plants derived from the fusion of protoplasts of Nicotiana glauca and N. langsdorffii contains the small subunit polypeptides of both parent species and the large subunit polypeptides of only N. glauca. Fraction 1 protein isolated from the leaves of a hybrid plant obtained after the uptake of chloroplasts of N. suaveolens by protoplasts of white tissue of a variegating mutant of N. tabacum contains the large subunit polypeptides of both N. suaveolens and N. tabacum, as well as the small subunit polypeptides of both these species.  相似文献   

Chondrite barium, neodymium, and samarium isotopic heterogeneity and early Earth differentiation     

Carlson RW  Boyet M  Horan M 《Science (New York, N.Y.)》2007,316(5828):1175-1178

Isotopic variability in barium, neodymium, and samarium in carbonaceous chondrites reflects the distinct stellar nucleosynthetic contributions to the early solar system. We used 148Nd/144Nd to correct for the observed s-process deficiency, which produced a chondrite 146Sm-142Nd isochron consistent with previous estimates of the initial solar system abundance of 146Sm and a 142Nd/144Nd at average chondrite Sm/Nd ratio that is lower than that measured in terrestrial rocks by 21 +/- 3 parts per million. This result strengthens the conclusion that the deficiency in 142Nd in chondrites relative to terrestrial rocks reflects 146Sm decayand earlyplanetary differentiation processes.  相似文献   

Neodymium-142 evidence for Hadean mafic crust     

O'Neil J  Carlson RW  Francis D  Stevenson RK 《Science (New York, N.Y.)》2008,321(5897):1828-1831

Neodymium-142 data for rocks from the Nuvvuagittuq greenstone belt in northern Quebec, Canada, show that some rock types have lower 142Nd/144Nd ratios than the terrestrial standard (epsilon142Nd = -0.07 to -0.15). Within a mafic amphibolite unit, 142Nd/144Nd ratios correlate positively with Sm/Nd ratios and produce a 146Sm-142Nd isochron with an age of 4280(-81)(+53) million years. These rocks thus sample incompatible-element-enriched material formed shortly after Earth formation and may represent the oldest preserved crustal section on Earth.  相似文献   

Isolation and structure of higher diamondoids,nanometer-sized diamond molecules   总被引：1，自引：0，他引：1  

Dahl JE  Liu SG  Carlson RM 《Science (New York, N.Y.)》2003,299(5603):96-99

We exploited the exceptional thermal stability and diverse molecular shapes of higher diamondoids (C22 and higher polymantanes) to isolate them from petroleum. Molecules containing 4 to 11 diamond-crystal cages were isolated and crystallized, and we obtained single-crystal x-ray structures for representatives from three families. Rigidity, strength, remarkable assortments of three- dimensional shapes, including resolvable chiral forms, and multiple, readily derivatizable attachment sites make them valuable nanometer-size molecular building blocks.  相似文献   

Long-term satellite record reveals likely recent aerosol trend     

Mishchenko MI  Geogdzhayev IV  Rossow WB  Cairns B  Carlson BE  Lacis AA  Liu L  Travis LD 《Science (New York, N.Y.)》2007,315(5818):1543

Analysis of the long-term Global Aerosol Climatology Project data set reveals a likely decrease of the global optical thickness of tropospheric aerosols by as much as 0.03 during the period from 1991 to 2005. This recent trend mirrors the concurrent global increase in solar radiation fluxes at Earth's surface and may have contributed to recent changes in surface climate.  相似文献   

THE SEGREGATION OF PHYSICAL GEOGRAPHY     

Carlson FA 《Science (New York, N.Y.)》1925,61(1579):366

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Production of Starch-like Material From Glucose-1-phosphate by Diphtheria Bacilli     

Hehre EJ  Carlson AS  Neill JM 《Science (New York, N.Y.)》1947,106(2761):523-524

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THE FEDERATION OF AMERICAN SOCIETIES FOR EXPERIMENTAL BIOLOGY     

Carlson AJ 《Science (New York, N.Y.)》1914,39(997):217-218

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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   

RESOLUTION OF THE EXECUTIVE COMMITTEE     

Barker JW  Caldwell OW  Cannon WB  Carlson AJ  Compton AH  Livingston BE  Mather KF  Moulton FR  Stakman EC  Wrather WE 《Science (New York, N.Y.)》1944,99(2565):159-160

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