The NS article is

 issue 2556 of New Scientist magazine, 19 June 2006, page 50

the actual published work is

Cell, vol 122, p 133

What he measured was the age of carbon in DNA, which is only a tiny
fraction of the total number of atoms making up a cell. So I guess you
are right in your more restricted meaning of "same".

Cheers

On Sun, Oct 08, 2006 at 11:52:49AM +1000, Stathis Papaioannou wrote:
> 
> Russell Standish writes:
> 
> > On Sun, Oct 08, 2006 at 12:35:44AM +1000, Stathis Papaioannou wrote:
> > >  This is 
> > > literally true, given that from moment to moment, even in the absence of 
> > > teleportation 
> > > etc., the atoms in your body turn over such that after a certain time 
> > > none of the 
> > > matter in your body is the "same", and before this time the fact that 
> > > some of the 
> > > matter in your body is the "same" is accidental and makes no difference 
> > > to your 
> > > conscious experience.
> > > 
> > 
> > We _really_ need to dispell this myth. It turns out that A bomb tests
> > prior to the partial test ban treaty provides a unique clock that
> > allows one to measure when a particular cell was born. It turns out
> > that whilst this statement is true of various organs (eg the gut in
> > particular), neurons turn out to have an average age just two years
> > less than the age of the person (as measured in cadavers), ie most are
> > born during the rapid brain expansion that occurs during the first two
> > years of life.
> > 
> > This is crucial, because I would suspect that neurons have far more
> > relevance to one's person, than do gut cells.
> > 
> > I posted on this before - it was reported in a recent New Scientist. I
> > can dig out the reference if people are interested.
> 
> I'd be interested in the reference. However, I wasn't referring to turnover 
> of cells, but 
> to turnover of components of cells. Water and electrolytes are freely and 
> continuously 
> turned over while proteins and other structural components are continuously 
> breaking 
> down and being replaced. I'm not sure of the numbers but I would guess that 
> only a tiny 
> percentage of the matter in a neuron would be the same years later. If there 
> are trillions 
> of radioactive atoms to begin with then by chance some of them will persist 
> in a particular 
> cell provided it does not die. What is actually preserved in a neuron which 
> survives over 
> the course of a person's life is a rough template and physical continuity, 
> not the matter it 
> is comprised of. But for a few lucky atoms, ordinary living is equivalent to 
> destructive 
> teleportation.
> 
> Stathis Papaiaonnou 
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