987 resultados para 548 Crystallography
Resumo:
2 Seiten
Resumo:
Text zu einer Ausstellung
Resumo:
107 Briefe zwischen Max Horkheimer und Leo Löwenthal; 10 Briefe von Max Horkheimer an Samuel H. Flowerman (Sandy); 1 Brief von Samuel H. Flowerman an Frederick Pollock, 26.03.1946; 2 Briefe von Max Horkheimer an Herbert Marcuse, 1946; 1 Brief von Leo Löwenthal an Reiwald, [Juli 1946]; 1 Brief von Max Horkheimer an John Slawson, [Juli 1946]; 1 Brief von dem American Jewish Committee an Leo Löwenthal, 20.06.1946; 1 Brief von dem Coulmbia University Bookstore (New York) an Leo Löwenthal, 18.06.1946; 1 Brief von Frank D. Fackenthal an Max Horkheimer, 14.06.1946;
Resumo:
3 Briefe zwischen Robert M. Mac Iver und Frederick Pollock, 1943; 1 Brief von dem Office of Strategic Services (Washington) an Frederick Pollock, 14.09.1943; 1 Brief von dem U. S. Government Printing Office (Washington) an Frederick Pollock, 01.09.1943; 1 Brief von Frederick Pollock an Franco Bruno Averardi, 19.07.1943; 1 Brief von Frederick Pollock an Leo Löwenthal, 15.07.1943; 1 Brief von Emil E. Mayer an F. Landauer, 28.05.1943; 2 Briefe zwischen Frederick Pollock und Erich Rosenberg, 1943; 1 Brief von Frederick Pollock an George Mintzer, 12.05.1943; 1 Brief von Iago Galdstone (Arzt) an Frederick Pollock, 10.05.1943; 1 Brief von Frederick Pollock an Theodor W. Adorno, 11.05.1943; 1 Brief von Frederick Pollock an den British Information Services (New York), 11.05.1943;
Resumo:
Oxygen- and carbon-isotope analyses have been performed on the Quaternary planktonic foraminifers of Sites 548 and 549 (DSDP Leg 80) to investigate major water mass changes that occurred in the northeastern Atlantic at different glacial-interglacial cycles and to compare them with the well-defined picture of 18,000 yr. ago. Oxygen-isotope stratigraphy also provides a chronological framework for the more important data on the fauna and flora. Although bioturbation and sedimentary gaps obliterate the climatic and stratigraphic record, general trends in the oceanographic history can be deduced from the isotopic data. Isotopic stratigraphy has tentatively been delineated down to isotopic Stage 16 at Site 548 and in Hole 549A. This stratigraphy fits well with that deduced from benthic foraminiferal d18O changes and with bioclimatic zonations based on foraminiferal associations at Site 549. Variations in the geographic extension and in the flux of the Gulf Stream subtropical waters are inferred from both d18O and d13C changes. Maximal fluxes occurred during the late Pliocene. Northward extension of subtropical waters increased through the various interglacial phases of the early Pleistocene and decreased through the late Pleistocene interglacial phases. Conversely, glacial maxima were more intense after Stage 16. Isotopic Stages 12 and 16 mark times of important change in water mass circulation. Oxygen- and carbon-isotope analyses have been performed on the Quaternary planktonic foraminifers of Sites 548 and 549 (DSDP Leg 80) to investigate major water mass changes that occurred in the northeastern Atlantic at different glacial-interglacial cycles and to compare them with the well-defined picture of 18,000 yr. ago. Oxygen-isotope stratigraphy also provides a chronological framework for the more important data on the fauna and flora. Although bioturbation and sedimentary gaps obliterate the climatic and stratigraphic record, general trends in the oceanographic history can be deduced from the isotopic data. Isotopic stratigraphy has tentatively been delineated down to isotopic Stage 16 at Site 548 and in Hole 549A. This stratigraphy fits well with that deduced from benthic foraminiferal d18O changes and with bioclimatic zonations based on foraminiferal associations at Site 549. Variations in the geographic extension and in the flux of the Gulf Stream subtropical waters are inferred from both d18O and d13C changes. Maximal fluxes occurred during the late Pliocene. Northward extension of subtropical waters increased through the various interglacial phases of the early Pleistocene and decreased through the late Pleistocene interglacial phases. Conversely, glacial maxima were more intense after Stage 16. Isotopic Stages 12 and 16 mark times of important change in water mass circulation.
Resumo:
Presently, the intermediate depths of the North Atlantic Ocean are occupied by a great lens of warm, saline water whose source is the Mediterranean Sea. This water flows both westward and northward, finally entering the Norwegian Sea where it may contribute to the formation of North Atlantic Deep Water. The Late Neogene history of Mediterranean Outflow in the Atlantic can be monitored at DSDP-IPOD Site 548 on the continental slope Southwest of Ireland using benthic Foraminifera oxygen isotope values. Isotopic data from 154 samples indicate that Mediterranean water was absent from the mid-depth North Atlantic from 3.4 to 3.2 Ma ago. However, at about 2.9 Ma ago the isotopic values at Site 548 diverge from those recorded from the deep North Atlantic and they can be interpreted to indicate the appearance of a new water mass, possibly Mediterranean water, in the North Atlantic water column. This appearance may be related to climatic changes that occurred around the Mediterranean Basin at about 2.9 Ma ago. The analysis of 189 samples for grain-size distributions shows that a significant increase in the silt-size fraction occurs at the same level that isotopic analysis indicates a change in bottom waters at Site 548. The grainsize data support the hypothesis that mid-depth water-mass changes occurred at about 2.9 Ma ago.