Claesen et al. [4] recently presented an efficient method for computing the isotope pattern of a molecule, that is, both the isotope distribution and the center masses (also called “probabilityweighted masses” and “aggregated isotopic variants” in [4]) of the isotope peaks. They favorably compare their approach against five other methods for simulating isotope patterns: Their tool BRAIN is more...

Conspicuous global stable carbon isotope excursions that are recorded in marine sedimentary rocks of Phanerozoic age and were associated with major extinctions have generally paralleled global stable oxygen isotope excursions. All of these phenomena are therefore likely to share a common origin through global climate change. Exceptional patterns for carbon isotope excursions resulted from massi...

—Stable-isotope analysis of feathers is an increasingly important source of information on diet and movement of birds. Feathers are typically cleaned with a solvent before analysis, but the effects of this cleaning on the resulting data have not been examined critically. We conducted an experiment to determine whether a cleaning regime affected hydrogen ( D), carbon ( C), and nitrogen ( N) ...

Andean Ores, having been approved in respect to style and intellectual content, is referred to you for judgment. We have read this thesis and recommend that it be approved. Lead isotope ratios of ores and igneous rocks in the Central and Southern Andes show a large-scale geographic pattern related to magmatic source processes. This pattern changes in the Northern Andes for reasons that are not ...

A pilot study was performed to examine the potential of stable isotope techniques for monitoring the impact of a harmful substance on the cellular nitrogen metabolism in the ciliate species Tetrahymena pyriformis. After identical cultivation periods of control cells and toluene-exposed cells in a defined culture medium enriched with [guanidino-15N2]l-arginine, a number of nitrogen-containing po...

Identifying patterns and drivers of natural variability in populations is necessary to gauge potential effects of climatic change and the expected increases in commercial activities in the Arctic on communities and ecosystems. We analyzed growth rates and shell geochemistry of the circumpolar Greenland smooth cockle, Serripes groenlandicus, from the southern Barents Sea over almost 70 years bet...

The climatological nature of orographic precipitation in the southern Andes between 40° and 48°S is investigated primarily using stable isotope data from streamwater. In addition, four precipitation events are examined using balloon soundings and satellite images. The Moderate Resolution Imaging Spectroradiometer (MODIS) images taken during precipitation events reveal complex patterns of upstre...

The decrease in the average magnitude of carbon isotope excursions in marine carbonates over Phanerozoic time is a longstanding unresolved problem. In addition, carbon isotope excursions commonly co-occur with oxygen isotope excursions of the same sign, implying the existence of a longstanding link between organic carbon burial fluxes and temperature. It was proposed that this connection was pr...

The reductive carboxylation of ribulose-5-phosphate (Ru5P) by 6-phosphogluconate dehydrogenase (6PGDH) from Candida utilis was investigated using kinetic isotope effects. The intrinsic isotope effect for proton abstraction from Ru5P was found at 4.9 from deuterium isotope effects on V and V/K and from tritium isotope effects on V/K. The presence of 6-phosphogluconate (6PG) in the assay mixture ...