Effectively addressing marijuana trade is aided by understanding marijuana geographic sources. We analyzed the (87)Sr/(86)Sr of marijuana samples grown in 79 counties across the United States to determine if a primary geologic signal is retained in marijuana, which could therefore be useful for geographic sourcing. The marijuana results were compared with modeled bedrock (87)Sr/(86)Sr values ba...

Stable isotopes (Deuterium and Oxygen-18) have a broad application in many of water related sciences. Precipitation is the most important input to the water cycle which shows considrable spatial and temporal variability in its isotope content. To study the precipitation isotope content, 51 samples from August 2015 to July 2016 have been collected mainly on a monthly basis with few events based ...

For more than half a century isotopes have been employed as a powerful tool in studying various aspects of water resources in a largenumber of countries. However, in developing countries like Iran the application of such techniques is in its infancy. The first research inIran was carried out in 1975 to identify the source of saline groundwaters in south Iran, and the first national conference o...

Patterns of migratory connectivity are a vital yet poorly understood component of the ecology and evolution of migratory birds. Our ability to accurately characterize patterns of migratory connectivity is often limited by the spatial resolution of the data, but recent advances in probabilistic assignment approaches have begun pairing stable isotopes with other sources of data (e.g., genetic and...

A range of isotopic methods (using radioactive and stable isotopes) have been used to investigate groundwater processes and to determine the sources and pathways for groundwater contamination. Methods using stable isotopes of nitrogen have been applied in a variety of Australian and international groundwater studies. Isotopic methods have involved either application of tracer isotopes or studyi...

Stable isotopes have been extensively used to trace element cycles and their incorporation into food webs. This chapter provides a brief introduction to the principles of using stable isotopes as natural or deliberate tracers in estuarine systems, with a focus on (1) assessing the origin and cycling of organic and inorganic elements (mainly carbon and nitrogen), (2) defining estuarine food webs...

1. Stable isotope methods are being used to investigate the absorption of dietary iron. In order to be certain that this new methodology is accurate, we have compared results obtained using stable isotopes and inductively coupled plasma mass spectrometry with those determined using a radioisotope and whole body counting. 2. The stable isotope 54Fe (2.8 mg) was given to 10 healthy non-pregnant w...

The landmark experiments of Schoenheimer and Rittenberg in the 1930s provided the scientific foundation for the ensuing development and application of stable isotope techniques in clinical diagnosis and research. Stable isotopes are non-radioactive atoms of the same chemical element, which diVer only in their number of neutrons. Many elements also have radioactive (non-stable) isotopes. Aspects...

Satellite-based tracking of migratory waterfowl is an important tool for understanding the potential role of wild birds in the long-distance transmission of highly pathogenic avian influenza. However, employing this technique on a continental scale is prohibitively expensive. This study explores the utility of stable isotope ratios in feathers in examining both the distances traveled by migrato...