Re: [ccp4bb]: twinning detection

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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 Have you checked whether your data has a pseudo translational vector?
( run a native patterson and look for off-origin peaks)
If so this means many reflections are very weak, and the moments are not
a useful check.

You may be able to reduce the cell dimensiions, or maybe you have centring?
Eleanor

Zhang Fan wrote:
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> ***          CCP4 home page http://www.ccp4.ac.uk         ***
> 
> Dear all,
>     
>     I suspected that my data is twinned and carried out the twinning 
> detection using the input file detect_twinning.inp in CNS. I got the 
> following result:
>     
> ---------------------------averages-over-all-bins----------------------------- 
> 
> 
>   <|I|^2>/(<|I|>)^2 =    4.0639 (2.0   for untwinned, 1.5   for twinned)
>  (<|F|>)^2/<|F|^2>  =    0.5682 (0.785 for untwinned, 0.865 for twinned)
> ------------------------------------------------------------------------------ 
> 
> 
> 
> 
> Why the statistics of my data is so far away from the idea values for 
> either twinned or untwinned data. Is my data twinned or not from this 
> result?
>     
> Thanks in advance.
> Fan
> 
> 
> 
> 
> 
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