Biogeochemical implications of the isotopic equilibrium fractionation factor between the oxygen atoms of acetone and water     

Leonel da Silveira Lobo O&#x;Reilly Sternberg  Michael Joseph DiGiacomo DeNiro 《Geochimica et cosmochimica acta》1983,47(12):2271-2274

Carbonyl oxygens of organic molecules undergo isotopic exchange with water during reversible hydration reactions. The equilibrium isotopic fractionation factors between the carbonyl oxygen of acetone and water at 15°, 25°, and 35°C are 1.028, 1.028, and 1.026 respectively. The differences between the δ¹⁸O values of the carbonyl oxygen of acetone and of the water with which it is in equilibrium are similar to the differences that have been observed between the δ¹⁸O values of cellulose and the water used in its synthesis by a variety of aquatic plants and animals. Additionally, the identity of the acetone-water fractionation factors at 15° and 25°C parallels the observation that the difference between the δ¹⁸O values of cellulose and water shows no temperature dependence for individual species of plants grown over the same temperature range. These results are discussed in relation to the proposal that the oxygen isotopic relationship between cellulose and water is established by isotopic exchange occurring during the hydration of carbonyl groups of the intermediates of cellulose synthesis.  相似文献   

Erratum to: Quantifying and monetizing potential climate change policy impacts on terrestrial ecosystem carbon storage and wildfires in the United States     

David Mills  Russell Jones  Karen Carney  Alexis St. Juliana  Richard Ready  Allison Crimmins  Jeremy Martinich  Kate Shouse  Benjamin DeAngelo  Erwan Monier 《Climatic change》2015,131(1):179-181

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Changes in extreme daily rainfall for São Paulo, Brazil     

Maria A. F. Silva Dias  Juliana Dias  Leila M. V. Carvalho  Edmilson D. Freitas  Pedro L. Silva Dias 《Climatic change》2013,116(3-4):705-722

Significant positive trends are found in the evolution of daily rainfall extremes in the city of São Paulo (Brazil) from 1933 to 2010. Climatic indices including ENSO, PDO, NAO and the sea surface temperature at the coast near São Paulo explain 85 % of the increasing frequency of extremes during the dry season. During the wet season the climatic indices and the local sea surface temperature explain a smaller fraction of the total variance when compared to the dry season indicating that other factors such as the growth of the urban heat island and the role of air pollution in cloud microphysics need to be taken into account to explain the observed trends over the almost eight decades.  相似文献