To add to the discussion a plot of the acentric K&W from -10 to 10 (normalised wrt sqrt(sigma) ). ftp://ftp.ccp4.ac.uk/ccb/aZF2.pdf,
black dots are F/sqrt(sigma) while blue is corresponding plot for sigma
The value drops from 0.42 to 0.28 going from h = -4 to h = -10.
Note: for this we are heading for F/sigF of ~1.92.
In ctruncate the norm is corrected (somewhat) for anisotropy, while for cases with twinning or NCS the default is to use a flat prior (in intensity).
Charles
On 19 Jun 2013, at 14:29, Kay Diederichs wrote:
> On Wed, 19 Jun 2013 14:19:19 +0100, Kay Diederichs <[log in to unmask]> wrote:
>
>> I wonder if problem b) is why Evans and Murshudov observe little contribution of reflections in shells with CC1/2 below 0.27 in one of their test cases, which had very anisotropic data.
>
> sorry, forgot the reference. The paper is "How good are my data and what is the resolution?" by PR Evans and GN Murshudov (2013) ActaD 69, 1204-1214, accessible at http://journals.iucr.org/d/issues/2013/07/00/ba5190/index.html
>
> Kay
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