985 resultados para 333.5
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We reconstruct the latest Paleocene and early Eocene (~57-50 Ma) environmental trends in the Arctic Ocean and focus on the Paleocene-Eocene thermal maximum (PETM) (~55 Ma), using strata recovered from the Lomonosov Ridge by the Integrated Ocean Drilling Program Expedition 302. The Lomonosov Ridge was still partially subaerial during the latest Paleocene and earliest Eocene and gradually subsided during the early Eocene. Organic dinoflagellate cyst (dinocyst) assemblages point to brackish and productive surface waters throughout the latest Paleocene and early Eocene. Dinocyst assemblages are cosmopolitan during this time interval, suggesting warm conditions, which is corroborated by TEX86'-reconstructed temperatures of 15°-18°C. Inorganic geochemistry generally reflects reducing conditions within the sediment and euxinic conditions during the upper lower Eocene. Spectral analysis reveals that the cyclicity, recorded in X-ray fluorescence scanning Fe data from close to Eocene thermal maximum 2 (~53 Ma, presence confirmed by dinocyst stratigraphy), is related to precession. Within the lower part of the PETM, proxy records indicate enhanced weathering, runoff, anoxia, and productivity along with sea level rise. On the basis of total organic carbon content and variations in sediment accumulation rates, excess organic carbon burial in the Arctic Ocean appears to have contributed significantly to the sequestration of injected carbon during the PETM.
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Includes index.
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Se realizó un estudio epidemiológico de casos y controles en el cual se estableció la relación de causalidad entre factores de riesgo socioculturales, sanitarios e higiénicos, con la presentación de enfermedad diarréica aguda en Centro de Salud
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B3LYP/6-31++G** calculations to study seven tautomers of 5-methylcytosine in aqueous media have been carried out. Optimized geometries and relative stabilities for the different tautomers have been calculated in the gas phase, including interaction with two discrete water molecules and taking into account the solvent effects by using the self-consistent reaction field theory. The role of specific and bulk contributions of solvent effect on the observable properties of the 5-methylcytosine is clarified. The amino-oxo form is the most abundant tautomer in aqueous media. A reaction pathway connecting amino-oxo and amino-hydroxy forms along the corresponding transition structures has been characterized. Good agreement between theoretical and available experimental results of harmonic vibration frequencies is found. (C) 2001 Elsevier B.V. B.V. All rights reserved.
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5 Briefe zwischen Konrad Wittwer und Max Horkheimer, 1936, 1938, 1939; 1 Brief von Max Horkheimer an Joseph Wohl, 18.08.1934; 1 Brief von Max Horkheimer an Hedwig Wollenberger, 25.02.1941; 2 Briefe zwischen Richard Wolf und Max Horkheimer, 22.10.1938, 07.11.1938; 2 Briefe zwischen Martha Wolfenstein und Max Horkheimer, 11.10.1937, 19.10.1937; 1 Brief von Clemy Wolff an Leo Löwenthal, 05.03.1941; 2 Briefe zwischen Ilse Wolff und Max Horkheimer, 29.08.1937, 03.09.1937; 1 Brief von Max Horkheimer an Howard Woolston, 25.03.1941; 1 Einladung von der Women's Conference, 1935; 1 Brief von Max Horkheimer an die Women's Conference, 15.03.1935; 1 Brief von der World Foundation an Max Horkheimer, 26.11.1937; 2 Briefe vom World Jewish Congress an Max Horkheimer, 1942, 1945; 1 Brief von Max Horkheimer an Francis Henry Russel, 28.09.1942; 1 Brief von Max Horkheimer an Dr. Opie, 28.09.1942; 1 Brief der Württembergische Hypothekenbank an Max Horkheimer, 24.12.1930; 12 Briefe zwischen Rösle Wuestholz und Max Horkheimer, 1935-1937, 1939; 1 Brief von Max Horkheimer an Frida Wunderlich, 22.11.1937; 1 Brief von Max Horkheimer an die Yale University Library, 22.12.1938; 2 Briefe zwischen Owen D. Young und Max Horkheimer, 22.04.1940, April 1940; 3 Briefe zwischen Hans Zeisel und Max Horkheimer, 21.07.1941, 1941, 1944; 2 Briefe zwischen der Zentrale Hilfsstelle für deutsche Flüchtlingskinder Prag und Max Horkheimer, 01.03.1938, 25.04.1938; 6 Briefe zwischen Gregory Zilboorg und Max Horkheimer, 1939; 16 Briefe und Beilage an Max Horkheimer und F. Pollock von Edgar Zilsel, 1939-1942; 1 Brief vom Social Science Research Counsil an Edgar Zilsel, 01.04.1940; 1 Brief von The Rockefeller Foundation an Edgar Zilsel, 20.06.1939; 9 Briefe und Beilage von Max Horkheimer und F. Pollock an Edgar Zilsel, 1939-1942 sowie Briefwechsel mit Betty Drury; 10 Briefe zwischen The Rockefeller Foundation und Max Horkheimer, 1939-1940; 1 Brief von Max Horkheimer an Edgar Zilsel, 20.06.1939; 12 Briefe zwischen Betty Drury und F. Pollock, 1939-1940; 7 Briefe zwischen Alexander Zinnemann und Max Horkheimer, 1936;
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16 Briefe zwischen Ruth Nanda Anshen und Max Horkheimer, 1938-1941; 5 Briefe zwischen Peter Appel und Max Horkheimer, 1937; 1 Drucksache der Arbeitsgemeinschaft Sozialistischer Ärzte in Hessen, Juli 1949; 1 Brief der Arbeitsgemeinschaft für Soziale Betriebsgestaltung in Heidelberg an Max Horkheimer, 18.10.1949; 2 Briefe zwischen Lois Archer und Max Horkheimer, 24.07.1947, 04.08.1947; 2 Briefe zwischen Camille Arnaud und Max Horkheimer, 03.03.1946, 22.03.1946; 39 Briefe zwischen Raymond Aron und Max Horkheimer, 1935-1938; 2 Briefe zwischen Ruth Arrau und Max Horkheimer, 28.06.1949, 10.10.1949; 3 Briefe zwischen S. Aufhauser und Max Horkheimer, 1939-1941, 16.04.1941; 8 Briefe zwischen der Zeitschrift 'Aufbau' und Max Horkheimer, 1944-1944; 3 Briefe zwischen der Automobile Club of New York und Max Horkheimer, 1937, 10.08.1937;
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A multivariable approach utilising bulk sediment, planktonic Foraminifera and siliceous phytoplankton has been used to reconstruct rapid variations in palaeoproductivity in the Peru-Chile Current System off northern Chile for the past 19000 cal. yr. During the early deglaciation (19000-16000 cal. yr BP), our data point to strongest upwelling intensity and highest productivity of the past 19 000 cal. yr. The late deglaciation (16000-13000 cal. yr BP) is characterised by a major change in the oceanographic setting, warmer water masses and weaker upwelling at the study site. Lowest productivity and weakest upwelling intensity are observed from the early to the middle Holocene (13000-4000 cal. yr BP), and the beginning of the late Holocene (<4000 cal. yr BP) is marked by increasing productivity, mainly driven by silicate-producing organisms. Changes in the productivity and upwelling intensity in our record may have resulted from a large-scale compression and/or displacement of the South Pacific subtropical gyre during more productive periods, in line with a northward extension of the Antarctic Circumpolar Current and increased advection of Antarctic water masses with the Peru-Chile Current. The corresponding increase in hemispheric thermal gradient and wind stress induced stronger upwelling. During the periods of lower productivity, this scenario probably reversed.
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Fil: Calcagno, Duilio.