Sentences with phrase «isotope ratios»

The stable carbon isotope ratio of atmospheric CO2 (δ13Catm) is a key parameter in deciphering past carbon cycle changes.

More recently, in the Paleocene - Eocene Thermal Maximum, about 55 million years ago, a rise of 5oC in ocean temperature (recorded in stable isotope ratios in various geological deposits) and 8oC on land occurred.

A study by Thomas, Dennis et al 2009 [8] derived a high resolution temperature proxy record from oxygen isotope ratios from the ice core.

No one has yet determined the carbon isotope ratio for Mars.

The second factor was an increase in the weathering of the Appalachian rocks between 462 and 454 million years ago, which is indicated by changes in strontium isotope ratios in Ordovician oceanic rocks (Geology, DOI: 10.1130 / g30152a.1).

By measuring isotope ratios in shells from some of these snails from as long ago as 1918, the researchers have demonstrated that they could reconstruct the subseasonal rainfall rate of past monsoon seasons.

In some ways, a California company seems an odd choice for an upstate New York scientist who was determined to put down roots, but with a 90 % market share of gas - source isotope ratio mass spectrometers, applying to Thermo Finnigan was pretty much a no - brainer for someone with Burdett's experience, and it worked out.

Ancient sediments that once resided on a lake bed and the ocean floor show sulfur isotope ratios unlike those found in other samples from the same time, calling into question accepted ideas about when the Earth's atmosphere began to contain oxygen, according to researchers from the U.S., Canada and Japan.

Although he worked on a variety of scientific problems, a common theme of his graduate work was the use of gas - source isotope ratio mass spectrometers.

But, but, but,... Regardless of any estimates of the number of trees, the amount of CO2 in the atmosphere has increased by something like 40 percent in just the last century or so, and the carbon isotope ratios show that the extra carbon probably came from fossil fuels.

The granite in these bags is destined for isotope ratio measurement at Lawrence Livermore National Laboratory's Center for Accelerator Mass Spectrometry (CAMS...

I too have personally researched temperature trends — in my case I looked at isotope ratios in coral.

The regular variation in isotope ratios suggests that rather than wandering at random from site to site, Diprotodon made the same round trip each year, following seasonal shifts in vegetation and rainfall.

So, despite the oceanic crust having been transported into Earth's mantle for a long time, the uranium isotope ratio of the subducted oceanic crust first differed from Earth's mantle only after the full oxidation of the oceans.

Tried the first case involving use of Isotope Ratio Mass Spectrometry (IRMS) drug testing technology, before the IAAF Anti-Doping Tribunal in Monte Carlo, Monaco.

Although scientists know that the tools for reconstructing past climates at polar latitudes are far from perfect, he says, pinning down the relationship between isotope ratios and temperature is essential.

He probably created radioactivity to begin with, so isotope ratios are likely just some of his lies.

Only a CIR Blood Test (Carbon Isotope Ratio) can differentiate between Synthetic & Natural Testosterone & to give an example the difference between 400 NG / DL T - Level & 900 NG / DL is the difference between battling a strong man & a Gorilla & WADA labs do Not use CIR testing — USADA does use the CIR

By reconstructing the initial radium isotope ratio of the wastewater that contaminated the soil, Vengosh's team can determine the source of the fluids even if the wastewater itself is no longer present at the site.

Two recent models for the formation of the Moon, one that allows exchange through a silicate atmosphere (top), and another that creates a more thoroughly mixed sphere of a supercritical fluid (bottom), lead to different predictions for potassium isotope ratios in lunar and terrestrial rocks (right).

Investigation of ash sediments from recent Mt. Pinatubo eruptions and other major volcanic events show a signature of mass independent isotope ratios of sulfur, while sediment from minor eruption does not.

Stable carbon isotope ratio analyses on trace methane from ice samples.

The group also reveals that the greatest change in nitrogen isotope ratios occurred between 1950 and 1980, following a rapid increase in fossil fuel emissions.

cooler temperatures are associated with increased isotope ratios).

This leads to a lowering of the atmospheric 13C / 12C isotope ratio, which takes years to centuries to work its way through the carbon cycle (Keeling et al., 1980; Tans et al., 1993; Ciais et al., 1995a, b).

«Oxygen in the water that mammals drink is preserved in the phosphate in their teeth, so these can be used to calculate isotope ratios.

Characteristics of preserved vegetation, animals, pollen, and isotope ratios provide information.

The gas - source isotope ratio variety is especially widely used by geologists.

When the researchers analyzed the oxygen isotope ratios over the past 8,000 years, they found that the jet stream became wavier — with colder Eastern winter weather and warmer Western winter weather — on about a 4,000 - year cycle.

The team has analyzed the ratios of noble gas isotopes from deep within Earth's mantle, and has compared these results to isotope ratios closer to the surface.

Professor Mukhopadhyay continued «The geochemistry indicates that there are differences between the noble gas isotope ratios in different parts of Earth, and these need to be explained.

Hallis says the discovery of a deep reservoir of material with protosolar isotope ratios supports the idea that the hot, early Earth somehow retained this water.