X-Message-Number: 29491
Subject: Re: More on Gavrilov
References: <>
From: "Perry E. Metzger" <>
Date: Sat, 05 May 2007 16:03:17 -0400

> From: "Basie" <>
> Subject: More on Gavrilov
> Date: Thu, 3 May 2007 14:24:53 -0400
>
> Perhaps you are the one that does not understand.
>
>  " The theory explains why mortality rates increase exponentially with age 
> (the Gompertz law) in many species, by taking into account the initial flaws 
> (defects) in newly formed systems"

You conveniently ignored the portions of my message that explain what
that sentence means.

Again, without the assumption of initially defective parts (parts
can be regarded as mathematically abstract here), the statistical
distribution would be different, especially in the early part of the
curve, but there is no claim of any sort that the terminal mortality
rate at the end of the curve is in any way related to the number of
initial defective "parts" -- indeed, one of the pieces of evidence for
the Gavrilovs' position is that it explains the fact that mortality
rates stop increasing with age after a certain point.

If you believe the Gavrilovs' model, maximum lifespan would be
dictated by the rate of unrepaired failures, which makes intuitive
sense given that they're using a reliability theory based statistical
model.  There is no claim in any of the Gavrilovs' papers that you can
explain the difference between maximum lifespan in different species
by the number of "defective cells" at birth, and indeed any such
reading is not merely a distortion but a whole cloth fabrication.

> The organism is a system with initial flaws (defective cells).  The ratio of 
> good to bad determines the organisms rate of aging. Which is different for 
> every specie.

I would suggest that anyone wishing to assess relative credibility
between my statements and yours should read the original article and
search for any section that supports "Basie"'s contention. There is no
need for anyone to take my word for it.

http://longevity-science.org/JTB-01.pdf

I will quote one critical section from the paper for the benefit of
those that don't want to go through the thing themselves. It
summarizes the kernel of their ideas very well. (Taken from pages 530-531:)

    The phenomena of mortality increase with age and the subsequent
    mortality leveling-of are theoretically predicted to be an
    inevitable feature of all reliability models that consider aging
    as a progressive accumulation of random damage (Gavrilov &
    Gavrilova, 1991). The detailed mathematical proof of this
    prediction for some particular models is provided in the next two
    sections of this article.

    In short, if the destruction of an organism occurs not in one but
    in two or more sequential random stages, this is sufficient for
    the phenomenon of aging (mortality increase) to appear and then to
    vanish at older ages. Each stage of destruction corresponds to one
    of the organism's vitally important structures being damaged.

    In the simplest organisms with unique, critical structures, this
    damage usually leads to their deaths. Therefore, defects in such
    organisms do not accumulate, and the organisms themselves do not
    age -- they just die when damaged. In more complex organisms with
    many vital structures and significant redundancy, every occurrence
    of damage does not lead to death because of this
    redundancy. Defects do accumulate, therefore, giving rise to the
    phenomenon of aging (mortality increase). Thus, aging is a direct
    consequence (trade-off) of systems redundancy that ensures
    increased reliability and lifespan of organisms. As defects
    accumulate, the redundancy in the number of elements finally
    disappears. As a result of this redundancy exhaustion, the
    organism degenerates into a system with no redundancy, that is, a
    system with elements connected in series, with the result being
    that any new defect leads to death. In such a state, no further
    accumulation of damage can be achieved, and the mortality rate
    levels off.

You note that there is no reference there to your entirely whole cloth
invented notion that aging rates are determined by, quoting you,
"[t]he ratio of good to bad determines the organisms rate of
aging. Which is different for every specie[sic]."

> There is a good article on Wikipedia.
> http://en.wikipedia.org/wiki/Reliability_theory_of_aging_and_longevity with 
> numerous references to other work by this author.

That article doesn't contain the word "cell" once, nor does it support
any of your claims. (I'm sure you could now vandalize the article to
contain such words, this being Wikipedia, but such words are not there
as of the moment I write this.)

I'll be blunt here. You're clearly not capable of reading these papers
and understanding them. I have no opinion on why that might be, but it
is, none the less, the case. You are quite clearly not someone to be
relied upon as a reasonable interpreter of the literature.

Having said that, I'll bow out of this. My only purpose was to make
sure third parties reading understood that you were incorrect,
and I think that purpose has been achieved.


Perry

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