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Re: [ccp4bb]: A simple question of resolution



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Phil Evans wrote:
> 
> Why use a cut off in refinement? This is unecessary and a Bad Thing to do
> 

If one does not use a cut-off on F/SigF, why use a resolution cutoff?
There is nothing intrinsically objectionable about High Resolution Data,
the only reason I can see for excluding them is if they are weak (nonexistent).

Is it better to use a resolution cutoff which excludes a small number of 
5-10 sigma reflections in the last shell while keeping 0.5 sigma reflections
at lower resolution, or a sigma cutoff which rejects weak reflections
wherever they occur?

(this just to elicit more discussion- I am a firm believer in a zero F/sigF
cutoff AND using resolution as far as truncate will allow). How to
report the resolution without misleading is then a problem. I would
favor Bart Haze's/Gerard Kleywegt's "effective resolution" based on the 
number of reflections above some cutoff.

Ed