From: Anders Sandberg (asa@nada.kth.se)
Date: Sun Aug 25 2002 - 01:42:28 MDT
On Sat, Aug 24, 2002 at 02:29:28PM -0700, Robert J. Bradbury wrote:
>
> On Sat, 24 Aug 2002, Joao Magalhaes wrote:
>
> > The best explanation I know is hormesis. Hormesis is
> > the name given to the stimulatory effects caused by low levels of
> > potentially toxic agents. Basically, if you stress an organism -- with, for
> > example, radiation -- it will stimulate its defences and it will thus be
> > stronger afterwards.
>
> I'm afraid I have to agree with Joao, and not with Anders in spite of the
> nice mathematical model. [Quick everyone, mark Aug 24 2002 in your books
> as a day Anders may have been wrong -- it may be another decade before we
> see a similar event.]
:-) Actually, my model is general enough to swallow hormesis - the issue
is how the radiation level affects the rate constants (if you have
enough constants to play with, you can model anything). I have played
around with it, and it seems very hard to get a hormesis effect if you
assume a monotonic relationship between radiations and rates. By making
the dependency nonmonotonic it is easy to get a hormesis curve, but that
is cheating.
Hormesis seems to be a very general phenomenon, although it is not found
*everywhere*. There seems to be quite a lively debate about it in the
radiation exposure and toxicology community - finding out whether a
certain threat exhibits hormesis or not has big regulatory effects.
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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