On Mon, 2009-01-12 at 10:42 +0000, Ian Tickle wrote: > I was taught 'structure amplitude' - makes perfect sense to me! Why > does 'structure amplitude' make any less sense than 'structure factor'? > > It also clearly made sense to Phil Coppens, a crystallographer of > considerable repute, see ITC Vol. B (2nd Ed.), sect 1.2., p.10: 'The > Structure Factor'. To quote the introduction to the section: "The > 'structure factor' is the central concept in structure analysis by > diffraction methods. Its modulus is called the 'structure amplitude'". > > Also I did a 'Google vote' for the two terms. 'Structure amplitude' has > 11300 hits. 'Structure factor amplitude' has only 4750. So all round I > would say that 'structure amplitude' wins by a considerable margin. >
Having had a quick look at the google results myself, I think that there is a problem is the methodology. Google doesn't take into account punctuation when searching. So the first search includes results such as 'structure. Amplitude', where the two words are in different sentences, or 'structure, amplitude' where the words are part of a list. Given this case, the winning margin is likely to be less. My preference would also be for the full 'Structure factor amplitude'. 'Structure amplitude' leaves me with visions of comparing the pdb files of a small single domain protein and a ribosome. Two structures having different sizes (or amplitudes). > Cheers > > -- Ian > > > -----Original Message----- > > From: owner-ccp...@jiscmail.ac.uk > > [mailto:owner-ccp...@jiscmail.ac.uk] On Behalf Of Pavel Afonine > > Sent: 11 January 2009 03:01 > > To: Ethan A Merritt > > Cc: CCP4BB@jiscmail.ac.uk > > Subject: Re: [ccp4bb] structure (factor) amplitude > > > > > > > > On 1/10/2009 5:14 PM, Ethan A Merritt wrote: > > > > On Saturday 10 January 2009, Bernhard Rupp wrote: > > > > > > Dear All, > > > > I am getting conflicting comments on the use of > > 'structure factor amplitude' > > vs. just > > 'structure amplitude' > > for |F|. > > > > > > > > ??? > > That's just... odd. > > > > |F| is the amplitude of F. > > But no way F is a "structure". > > > > > > > > I agree. If F is a structure factor then |F| is a structure > > factor amplitude. "structure amplitude" doesn't make much sense... > > Pavel. > > > Disclaimer > This communication is confidential and may contain privileged information > intended solely for the named addressee(s). It may not be used or disclosed > except for the purpose for which it has been sent. If you are not the > intended recipient you must not review, use, disclose, copy, distribute or > take any action in reliance upon it. If you have received this communication > in error, please notify Astex Therapeutics Ltd by emailing > i.tic...@astex-therapeutics.com and destroy all copies of the message and any > attached documents. > Astex Therapeutics Ltd monitors, controls and protects all its messaging > traffic in compliance with its corporate email policy. The Company accepts no > liability or responsibility for any onward transmission or use of emails and > attachments having left the Astex Therapeutics domain. Unless expressly > stated, opinions in this message are those of the individual sender and not > of Astex Therapeutics Ltd. The recipient should check this email and any > attachments for the presence of computer viruses. Astex Therapeutics Ltd > accepts no liability for damage caused by any virus transmitted by this > email. E-mail is susceptible to data corruption, interception, unauthorized > amendment, and tampering, Astex Therapeutics Ltd only send and receive > e-mails on the basis that the Company is not liable for any such alteration > or any consequences thereof. > Astex Therapeutics Ltd., Registered in England at 436 Cambridge Science Park, > Cambridge CB4 0QA under number 3751674
