Dear Francis, the spots will be excluded individually based on the inhomogeneous background, so you don't need to apply a resolution cutoff. However, once you have determined and refined your structure it may be worth predicting the intensity of these spots and put them back for map calculation, this might avoid gaps in your map corresponding to inter-atom distances for which data are missing in the resolution range of the ice rings; as long as this is done only for a relatively small set of reflections there is not much risk of introducing a bias here.
HTH, Bruno -----Message d'origine----- De : CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] De la part de Francis E Reyes Envoyé : Tuesday, October 11, 2011 5:17 PM À : CCP4BB@JISCMAIL.AC.UK Objet : [ccp4bb] Ice rings... All, So I have two intense ice rings where there appear to be lattice spots in between them. I understand that any reflections that lie directly on the ice ring are useless, however, how do software programs (HKL2000, d*Trek, mosflm, XDS) deal with these intermediate spots? It would seem to me that employing a 'resolution cut off' just before the ice ring (on the low resolution side) would be improper, as there are spots on the high resolution side of the ice. (see enclosed .tiff) In fact, how do these programs deal with spots lying on ice rings? Are they rejected by some algorithm by those programs during integration, or is it up to the scaling/merging (by SCALA for example) step to deal with them? Thanks! F ########################################################################### Dr. Bruno P. Klaholz Department of Integrated Structural Biology Institute of Genetics and of Molecular and Cellular Biology IGBMC - UMR 7104 - U 964 1, rue Laurent Fries BP 10142 67404 ILLKIRCH CEDEX FRANCE Tel. from abroad: 0033.388.65.57.55 Tel. inside France: 03.88.65.57.55 Fax from abroad: 0033.388.65.32.76 Fax inside France: 03.88.65.32.76 e-mail: klah...@igbmc.fr websites: http://www.igbmc.fr/ http://igbmc.fr/Klaholz
