The key is that methane gas from shale has a different chemical signature
to conventionally extracted gas.
The researchers used a method called gas chromatography-mass spectrometry to identify organic material preserved in the braziers, detecting marijuana's chemical signature
. They found a higher level of THC, the plant's main psychoactive constituent, than the low levels typically seen in wild cannabis plants, indicating it was chosen for its mind-altering qualities.
The chemical signature
of the isolated compounds was an exact match to the chemical signature
"The chemical signature
was clearly different from the 'native' Milky Way stars," Helmi said.
The formula that helped the astrophysicists at the university develop the experimental Martian soil is based on the chemical signature
of the soils on Mars collected by NASA's Curiosity rover, according to a study published in the journal Icarus.
But they kept noticing a chemical signature
that was only indoors and not outdoors.
A graduate student working with them was surveying chemicals in a classroom about 20 feet from DeCarlo's office, and came across a mysterious chemical signature
they couldn't explain.
'If you look at the chemical signature
of the remains, it becomes clear that this was a population that knew how to manipulate the soil and harvest from the sea,' says Cat Jarman, who has recently published two papers on data she gleaned from ancient islander's rib fragments.
"If we take a fish, we can measure its chemical signature
and relate it to the signature of leaves and the signature of algae to work out where it's getting its food from," the researcher added.
While studying the wind transport of water vapor, they found that the vapor's chemical signature
gave clues to the type of pollution it came from, suggesting that "there's a lot of potential to use it to improve our understanding of urban air pollution," according to Gabe Bowen, coauthor of the research, which recently appeared in the Proceedings of the National Academy of Sciences.
Marshall is working with her colleague, Craig Marshall, associate professor of geology at KU, to improve the way scientists detect condensed aromatic carbon, thought to be a chemical signature
of astrobiology, space.com reported.
Biological agents, chemicals that comprise poison gas and the materials found in explosives all give off a chemical signature
, he noted.