LNT - a semantic comment

["Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>]

The email below was sent to me directly (thank you!). I agree - the linear 

term will remain in the limit - some people in favor of thresholds may not 

like this aspect but it should be noticed - I don't see a possibility to 

circumvent the linear term (as the dose ->zero) of a Taylor series.



If anything, the Taylor series is general theory for functions. The 

mechanistic problem is about what the corresponding function actually looks 

like and it was in this sense I looked at the use of the word "theory". 

Bill's comment is indeed very important - what may look like thresholds in 

observations could conceal what is going on in the limit (I favor this idea 

of a linear component in the limit - it must not necessarily make people 

hysterically afraid of radiation).



To summarize, if we refer to the general Taylor aspect - LNT is a theory but 

most often I think that the context is more about "we don't know what is 

going on there (low doses)". One could say that the Taylor approach is the 

first step of a theory - then it is "just" to expand the theory with all the 

other elements of the mathematical series... :-)



Thanks again Bill.



My personal initiative only,



Bjorn Cedervall   bcradsafers@hotmail.com

--------------------------------------------------------------------



Dear Bjorn,

    One point that bothers me is this-Taylor's theorem shows that for small

enough changes in the independent variable, any function approximately 

behaves

linearly. So I have always thought that linearity was a first order

approximation to the unknown function in the low dose region and hence 

shouldn't

be a fundamental issue-the really important aspect is the assumption about 

the

value of the intercept-ie that it is zero.

Cheers,

Bill





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