References in periodicals archive ?
One of the best known examples of this is the effort to find a correlation between tree-ring dating and carbon 14 dating.
So, even in this case, using the most accurate of the dating methods (dendrochronology) to establish a correlation with the next most accurate method (carbon 14), there is a disparity.
(16) Yaacov Hanoka, "Torah, Science and Carbon 14," B'Or Ha'Torah, vol.
Now, Edouard Bard of the Center for Weak Radioactivity in Gif-sur-Yvette, France and his colleagues report they have used coral to calibrate the carbon 14 scale over the past 30,000 years, an advance one scientist describes as a "quantum leap." Their results suggest the carbon 14 method errs by a wide span -- producing dates as much as 3,500 years too young for material from 20,000 years ago, says the research team, which consists of Bard, Bruno Hamelin of the University of Aix-Marseille III and Richard G.
While carbon 14 specialists expected the scale needed correction, "They are all surprised it's that large," says Fairbanks.
Carbon dating involves measuring radioactive atoms of carbon 14 locked within organic material from plants and animals, which take up the carbon only while alive.
The timescale is not perfectly accurate, though, because the amount of carbon 14 in the environment fluctuates.
Because DNA is stable after a cell has gone through its last cell division, the concentration of carbon 14 in DNA serves as a date mark for when a cell was born and can be used to date cells in humans.
After death, levels of this isotope in animal and plant remains will slowly decay away, meaning scientists can estimate their age from the amount of carbon 14 that remains in the sample.
Phials of whisky extracted from the antique bottles are sent to the laboratory in Oxford, where the scientists burn the liquid and bombard the resulting gas with electrically charged particles so they can measure the quantities of carbon 14 in the sample.
Buchholz used the Laboratory's Center for Accelerator Mass Spectrometry to measure the amount of carbon 14 in DNA to establish the age of cardiac muscle cells in humans.
The researcher revealed that the study group determined the ages of heart cells by determining the time at which the sample's carbon 14 concentration corresponded to the atmospheric concentration.
In the study, carbon 14 concentrations were elevated in subjects compared to those people born up to 22 years before the beginning of nuclear bomb tests.
While the limited recovery in humans after a heart injury or attack indicates failing regeneration of heart cells, the researchers say that the renewal of heart cells, as indicated by the mixing of carbon 14 in the DNA, suggest that the development of pharmacological strategies to stimulate this process may be a rational alternative or complement to cell transplantation strategies for heart cell replacement.