[ccp4bb]: Re: refine using merged MAD data of all 3 wavelength?

["David J. Schuller" <schuller@uci.edu>]

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while i agree that redundancy is a good idea, i think getting the
redundancy at the same wavelength would be better. as for getting an
'average' anomalous signal from several wavelengths, some of which will
have a stronger signal, some will have no signal, and possibly others with
an intermediate signal; wouldn't you be better off getting your redundancy
from the wavelength with the strongest signal?


On Wed, 11 Oct 2000, Phraenquex VD wrote:

> I'd say this is a very good idea:  if your crystal did not decay, and if
> you don't have a higher-resolution (native) dataset you'd prefer to use,
> merging all datasets for super-high redundancy can only improve matters.
> Not sure about the averaging f'/f" - do any programs actually use this?
> > As title, I would like to know whether any one tried to use all 3 wavelength data merged/scaled
> > together for the refinement. I tried this on one structure and it appeared to improve the
> > refinement. I am not sure the theoretical/practical soundness of doing this. If the
> > crystal is stable, it should give a lot more redudency to the data and help the high resolution
> > bins. The anomalous/dispersion signals would be messed up but mostly they are not used in
> > refinement any way. We could even give an average f' and f" for the merged data, or could we? Any
> > comments?

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"The Wrong Hat is like wearing an enormous sign, duct-taped to a plumber's
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                        David J. Schuller
                        modern man in a post-modern world
                        University of California-Irvine
                        schuller@uci.edu