[phenixbb] Possible Twinned data
Phzwart
phzwart at gmail.com
Thu Jun 9 12:50:10 PDT 2011
Looks twinned to me. Can you send me the full logfile?
Verstuurd vanaf mijn iPhone
Op Jun 9, 2011 om 12:38 heeft Yuri <yuri.pompeu at ufl.edu> het volgende geschreven:
> Hello phenixers,
> I am a little bit at loss since this is the first time I have encountered this situation.
> I just collected preliminary data on a ligand soaked crystal. It goes to about 1.85 A. The centrics and acentrics reflections tests look a little deviant from ideal untwinned. I was looking at my xtriage log
> file and it seemed to me like I have some twinned fraction. Phenix says not. I realize too my completeness is not good.
> Any educated insight would be helpful as I have never dealt with twinning (if this actually the case).
> Log file section:
> Wilson ratio and moments
>
> Acentric reflections
> <I^2>/<I>^2 :1.650 (untwinned: 2.000; perfect twin 1.500)
> <F>^2/<F^2> :0.839 (untwinned: 0.785; perfect twin 0.885)
> <|E^2 - 1|> :0.649 (untwinned: 0.736; perfect twin 0.541)
>
>
> Centric reflections
> <I^2>/<I>^2 :2.099 (untwinned: 3.000; perfect twin 2.000)
> <F>^2/<F^2> :0.749 (untwinned: 0.637; perfect twin 0.785)
> <|E^2 - 1|> :0.703 (untwinned: 0.968; perfect twin 0.736)
>
>
>
> NZ test (0<=z<1) to detect twinning and possible translational NCS
>
>
> -----------------------------------------------
> | Z | Nac_obs | Nac_theo | Nc_obs | Nc_theo |
> -----------------------------------------------
> | 0.0 | 0.000 | 0.000 | 0.000 | 0.000 |
> | 0.1 | 0.052 | 0.095 | 0.171 | 0.248 |
> | 0.2 | 0.126 | 0.181 | 0.285 | 0.345 |
> | 0.3 | 0.197 | 0.259 | 0.371 | 0.419 |
> | 0.4 | 0.271 | 0.330 | 0.440 | 0.474 |
> | 0.5 | 0.334 | 0.394 | 0.499 | 0.520 |
> | 0.6 | 0.394 | 0.451 | 0.553 | 0.561 |
> | 0.7 | 0.447 | 0.503 | 0.600 | 0.597 |
> | 0.8 | 0.497 | 0.551 | 0.629 | 0.629 |
> | 0.9 | 0.541 | 0.593 | 0.660 | 0.657 |
> | 1.0 | 0.581 | 0.632 | 0.697 | 0.683 |
> -----------------------------------------------
> | Maximum deviation acentric : 0.062 |
> | Maximum deviation centric : 0.078 |
> | |
> | <NZ(obs)-NZ(twinned)>_acentric : -0.050 |
> | <NZ(obs)-NZ(twinned)>_centric : -0.021 |
> -----------------------------------------------
>
>
> L test for acentric data
>
> using difference vectors (dh,dk,dl) of the form:
> (2hp,2kp,2lp)
> where hp, kp, and lp are random signed integers such that
> 2 <= |dh| + |dk| + |dl| <= 8
>
> Mean |L| :0.441 (untwinned: 0.500; perfect twin: 0.375)
> Mean L^2 :0.270 (untwinned: 0.333; perfect twin: 0.200)
>
> The distribution of |L| values indicates a twin fraction of
> 0.00. Note that this estimate is not as reliable as obtained
> via a Britton plot or H-test if twin laws are available.
>
> Cheers,
> --
> Yuri Pompeu
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