Results 251 to 260 of about 65,167,055 (305)

Deuterium and oxygen-18 in the baltic sea

Chemical Geology: Isotope Geoscience section, 1988
Abstract Results are presented of deuterium and 18 O measurements of water samples collected at 15 stations covering the southern and central part of the Baltic Sea. In general, they confirm earlier findings with respect to vertical stratification of the heavy isotopes in the Baltic and their relation to salinity.
K. Frohlich, J. Grabczak, K. Rozanski
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Oxygen-18 in Estonian Natural Waters

Isotopenpraxis Isotopes in Environmental and Health Studies, 1987
The data of 1982–1985 from the Turikoja meteostation (East Estonia) on the isotopic composition of precipitation are generalized and the results compared to those of some European IAEA/WMO network station. The monthly weighted mean value of δ18 O is equal to −10.4‰ and the seasonal isotope gradient ▵δ18 O/▵t is 0.32.
J.-M. Punning, M. Toots, R. Vaikmäe
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The Structure Of Oxygen-18.

1957
PhD ; Nuclear physics ; University of Michigan, Horace H. Rackham School of Graduate Studies ; http://deepblue.lib.umich.edu/bitstream/2027.42/181935/2/5801379 ...
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Deuterium and oxygen 18 in rain water

Journal of Geophysical Research, 1963
The D and O18 contents of rain water are known to vary considerably with time and location. Dansgaard found a good correlation of the mean O18 content of rain with mean air temperature, which causes a latitudinal as well as a seasonal variation of O18 and a similar one for D.
D. Ehhalt, K. Knott, J. F. Nagel, J. C. Vogel   +3 more
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Isotopic Exchange, Photosynthesis and Oxygen 18

1972
For the last thirty years it has been assumed, taking the experiments of RUBEN and his colleages (1941) as a foundation, that photosynthetic oxygen comes from water. This hypothesis, already postulated in 1893 by BACH, has since been refuted by WARBURG (1962), one of the few who have openly attacked, over a space of many years, the theory of the ...
R. Gerster, J. Dupuy, P. Guérin De Montgareuil   +2 more
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Oxygen-18 studies on the conversion of proline to collagen hydroxyproline

Archives of Biochemistry and Biophysics, 1963
Abstract Oxygen-18 was used to study the synthesis of collagen hydroxyproline in vivo by chick embryos. The oxygen incorporated into the hydroxyl group was found to originate from atmospheric oxygen rather than water, and therefore the results indicate that an oxygenase mechanism is involved in the conversion of proline to hydroxyproline.
D, PROCKOP, A, KAPLAN, S, UDENFRIEND
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Oxygen-18 in Biological NMR

2007
The sections in this article are 1 Introduction 2 Properties of the 18O Isotope Shifts in NMR 3 Studies Utilizing 18O Isotope Shifts in 13C, 15N, and 31P NMR 4 Biographical Sketch Related ...
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Glacier Oxygen-18 Content and Pleistocene Ocean Temperatures

Science, 1969
The mean oxygen-18 content of continental ice sheets during the last glacial maximum is estimated to δO 18 =-30 per mille or less, and the consequent change in the isotopic composition of the oceans at that time to 1.2 per mille or more. This means that at least 70 percent of the oxygen-18 variations found in shells
W, Dansgaard, H, Tauber
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Oxygen-18 Abundance in Fresh Water

Nature, 1954
MASS spectrometric tests of the oxygen-18 abundance, a f, in a hundred and nine freshwater samples obtained from various parts of the world, have shown very considerable variations. When the samples are compared in relation to the climatic conditions of the area of collection, the results indicate a much decreased oxygen-18 abundance as the climate ...
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Oxygen-18 variations in belemnite guards

Earth and Planetary Science Letters, 1969
Abstract Spot measurements of the oxygen isotopic composition of carbonate were carried out on some Jurassic and Cretaceous belemnites. Both the well preserved and the badly preserved specimens show radial variations of the 18 O/ 16 O ratios.
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