We report new high resolution measurements of the elemental and isotopic composition of galactic cosmic ray B, C, N, and 0 nuclei with ~ 30 to ~ 130 MeV nucleon-•. These observations place limits on the isotopic composition of the cosmic ray source and restrict possible models of cosmic ray origin and propagation. In particular, we find that N is significantly depleted in the cosmic ray source ...

The isotopes 2H and 3He have been identified in low-energy cosmic rays during solar-quiet periods from 1973 January to 1974 October. These observations, made with the Caltech Electron/ Isotope Spectrometer on IMP-7, cover the energy intervals 5-29 MeV per nucleon for 2H and 7-50 MeV per nucleon for 3He. We find that the energy spectra oflH, 2H, and 3He all fall rapidly with decreasing energy, g...

Introduction The scientific community has actively debated for quite some time the possibility that conditions were once favorable for life to originate and evolve on Mars. However, as we know it, for life to survive, the presence of liquid water is essential. The present day climate on Mars is inhospitable for sustaining any life form. However, recent data from twin rovers, Spirit and Opportun...

Moisture availability is the factor that most commonly influences the discrimination against 13C fixation (∆) by C3 plants. Therefore, by changing the availability of moisture by way of controlling competing vegetation, ∆ in white spruce (Picea glauca (Moench) Voss) seedlings should be affected. The objective of this study was to determine the influence of manual brushing on ∆ in white spruce s...

The incorporation of dietary macronutrients and associated isotopic signatures of carbon (dC) and nitrogen (dN) into animal tissues is a result of the interaction between growth, nutritional status, and the composition of the diet. In mammalian carnivores incorporation is further complicated by lack of carbohydrates in the diet and allocation of large quantities of dietary macronutrients to fet...

The analysis of the four main isotopic N2O species (NNO, NNO, NNO, NNO) and especially the intramolecular distribution of N (“site preference”, SP) has been suggested as a tool to distinguish source processes and to help constrain the global N2O budget. However, current studies suffer from limited spatial and temporal resolution capabilities due to the combination of discrete flask sampling wit...

The geographical variability of the elemental concentration and isotopic composition of mercury and lead was evaluated in epiphytic lichens collected over a mesoscale area (Pyrenees-Atlantiques, Southwestern France). The sampling points have been selected according to different parameters in order to represent the main land use classification of the investigated territory (urban, industrial, ag...

We review the inventories of primordial noble gases and nitrogen in meteorites, their carrier phases, how and where they may have been incorporated, as well as processes modifying their abundances on meteorite parent bodies. Some of the many distinct noble gas and nitrogen components have an isotopic composition very different from that in the Sun. These components reside in presolar grains. “A...

Recent natural catastrophes with large-scale loss of life have demonstrated the need for a new technique to provide information for disaster victim identification when DNA methods fail to yield the identification of an individual, or in other situations where authorities need to determine the recent geographical life history of people. The latter may be in relation to the identification of indi...