Dear David, Although this is not exactly a topic of your question, an alternative approach is to use the resolution screening and compare the results. I have implemented this approach to my program SHELIXIR (because it uses SHELX C/D/E), which can be found here: http://kmlinux.fjfi.cvut.cz/~kolenpe1/shelixir/ It also has its GUI here: http://kmlinux.fjfi.cvut.cz/~kolenpe1/shelixir/gui/ Once you have enough computational power, you can easily perform such testing (and no longer need to understand everything that is written in the manuscript :-) ). I hope that the program will soon be published and I would welcome if you (or someone else) used it and potentially gave me some feedback or suggestion. The program has other functions like parallelized solvent content screening, etc. ;-) Feel free to ask for more. Best regards, Petr
PS: Although tested on a number of cases, the command line is more stable than the GUI. From: CCP4 bulletin board <[email protected]> On Behalf Of David Waterman Sent: Friday, December 18, 2020 12:53 PM To: [email protected] Subject: [ccp4bb] Anomalous signal to noise details Hi folks The paper "Substructure solution with SHELXD<https://journals.iucr.org/d/issues/2002/10/02/gr2280/index.html>" (Schneider & Sheldrick, 2002) describes how data can be truncated at the resolution at which [ΔF to its estimated standard deviation as a function of the resolution] drops to below about 1.3 Is this referring to the quantity <|ΔF|>/<σ(ΔF)> calculated in resolution shells, or the quantity <|ΔF|/σ(ΔF)> ? This entry<https://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php?title=SHELX_C/D/E#Resolution_cutoff_.28SHEL.29> on the ccp4wiki gives a cutoff where the mean value of |ΔF|/σ(ΔF) falls below about 1.2 (a value of 0.8 would indicate pure noise) this version sounds to me like <|ΔF|/σ(ΔF)> which is the "better" metric, and what do people mean when they say DANO/SIGDANO? What is the justification for the 1.3 (or 1.2) value? Thanks! -- David ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
