Hi Bernhard I'm sure you're right: it must be a typo. I think the problem is that people get into the habit of including the minus sign in EXP(-B*2*SINTH**2/L**2), e.g. when writing the expression for structure factor, without thinking whether the formula is actually applicable to the particular situation!
Cheers -- Ian > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Bernhard Rupp > Sent: 24 April 2007 01:20 > To: [email protected] > Subject: truncate Wilson printout > > Dear All, > > there is one line in the TRUNCATE output that makes > me question my sanity. > > Under the Wilson plot the log states: > > Least squares straight line gives: B = 12.743 SCALE > = 22.25070 > where F(absolute)**2 = SCALE*F(observed)**2*EXP(-B*2*SINTH**2/L**2) > > This is somewhat counterintuitive, because in order to get the > attenuated reflections fobs**2 *UP* to the unattenuated > fabs**2 I would > assume that I have to multiply with the inverse of the > B-factor attenuation, > EXP(B*2*SINTH**2/L**2) > > If I look at the plot, then plot is indeed from a graph > ln[(fobs**2)/fabs**2] = ln(k)-2B(sintol**2) > > thus > > ln(fobs**2)=ln(fabs**2)+ln(k)-2B(sintol**2) = > > fobs**2 =k*(fabs**2)*exp(-2B(sintol**2)) > > which essentially is the opposite of what truncate says, > I thus wonder if the inverse expression for bringing > relative to absolute intensities, i.e., scaling back > should be in truncate terms > > F(absolute)**2 = SCALE*F(observed)**2*EXP(B*2*SINTH**2/L**2) > > I know this is for sure the right way to bring > fobses back up to unitary Us and normalized Es. > > What am I missing here? > > Thx, br > -------------------------------------------- > Bernhard Rupp > www.ruppweb.org > -------------------------------------------- > > 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 [EMAIL PROTECTED] 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
