The STARANISO Server
Anisotropy of the Diffraction Limit
If you have some results that illustrate some beneficial effect of using the server on your data, and that you are happy to share with the community, please email the contact address at the bottom of the page.
In the case of unmerged data input the values of the half-dataset mean intensities are added automatically to the input data and the random-selection method is used.  The weighted 'σ-τ' method is used for merged input data unless the user includes columns labelled 'IHALF1' and 'IHALF2' as the half-dataset mean intensities, in which case the first method is used.  The advantage of using CC½ over the mean I /σ(I) as the cut-off criterion becomes apparent when the estimates of σ(I) are inaccurate, as appears to be the case for serial data.  Note that the 'σ-τ' method also relies on the σ(I) values being accurate so should not be used if those values are questionable.  The inverse-variance weighting also uses the σ(I) values but since the weighting is relative they need not be on the same scale as the values of Imean.
A fourth type of interactive colour-coded reciprocal-lattice display has been added when the input data are given as an unmerged XDS_ASCII.HKL file (not MTZ format).  The left-most scene then shows the value of the CORR statistic produced by XDS (item 11 in the file), i.e. for each reflection, the correlation coefficient between the observed reflection profile and the predicted profile that was used to integrate it.
The profile correlation plot gives a primary diagnostic of problems at the integration stage, as a mismatch of profiles could result from shortcomings in the sample (e.g. a cracked crystal) or in the profile estimation method (e.g. too coarse a partitioning of the detector surface).  As the profile correlation is given on a per-reflection basis, it is a more sensitive indication of such problems than the loss in <I /σ(I)> that it causes, since the latter quantity is a local average.
Either link to a saved bookmark, or enter here the 10- or 16-character job ID that was assigned on submission:
|Ian J. Tickle*||Andrew Sharff|
|Claus Flensburg||Oliver Smart|
|Peter Keller||Clemens Vonrhein|
|Wlodek Paciorek||Gérard Bricogne|