[phenixbb] phenix and weak data

Ed Pozharski epozh001 at umaryland.edu
Mon Dec 10 10:44:08 PST 2012


Pavel,

>  I mean not an R-factor improvement by a fraction of a percent or
> "cosmetics" like this, but a case where it is demonstrated that using
> it allowed more model to be built, or showing two maps side-by-side
> obtained without and with weak data where the latter would
> significantly be more useful (not just appears more pleasant after
> tweaking contouring thresholds to show the case favouritely). 

If the standard is that improvements in crystallographic refinement
process/algorithms only are justified when "more model can be built",
then many algorithm improvements should be abolished.  TLS refinement is
a widely accepted strategy, although it never (to my knowledge) was
really demonstrated that it allows you to magically see something new in
the density that was not there before.  You are right that a lot of
things we do to optimize crystallographic models do not change electron
density in a dramatic way.  You are absolutely wrong in your assertion
that improvements of the accuracy of model parameters are pointless. 

Cheers,

Ed.


-- 
I don't know why the sacrifice thing didn't work.  
Science behind it seemed so solid.
                                    Julian, King of Lemurs



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