JiscMail Logo
Email discussion lists for the UK Education and Research communities

Help for CCP4BB Archives


CCP4BB Archives

CCP4BB Archives


CCP4BB@JISCMAIL.AC.UK


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Monospaced Font

LISTSERV Archives

LISTSERV Archives

CCP4BB Home

CCP4BB Home

CCP4BB  July 2011

CCP4BB July 2011

Options

Subscribe or Unsubscribe

Subscribe or Unsubscribe

Log In

Log In

Get Password

Get Password

Subject:

Re: How to evaluate Fourier transform ripples

From:

Zbyszek Otwinowski <[log in to unmask]>

Reply-To:

[log in to unmask]

Date:

Wed, 6 Jul 2011 12:18:52 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (34 lines)

The question about Fourier transformation ripples has a straightforward
answer in a fairly typical situation:
A) data are collected to the resolution limit of diffraction,
B) phases are uniform in quality across the resolution range, which is
equivalent to R-free being uniform with respect to resolution within a
factor of 2 or so,
C) maps are not sharpened.

The ripples originate from not including unobserved structure factors. The
intensity of diffraction decreases rapidly past the measurability limit,
so, in the above situation, the unobserved diffraction contributes very
little. Consequently, the answer is that typically one should not see
ripples.
Ripples should not be confused with the effect of electron density maps
being smoothed by vibrations and other forms of disorder.

Zbyszek Otwinowski

>
> Dear All, Hi. I was asked in a manuscript revision to discuss
> about the possible effects of Fourier transformation ripples on the
> crystallographic results. Specifically, the reviewers question whether
> ripples may affect on the electron density around heavy metal center which
> has a Mo-S-As connection. From which angle or in which way this problem
> should be addressed most convincingly ? Thank you for any
> suggestion.Best,Conan


Zbyszek Otwinowski
UT Southwestern Medical Center at Dallas
5323 Harry Hines Blvd.
Dallas, TX 75390-8816
Tel. 214-645-6385
Fax. 214-645-6353

Top of Message | Previous Page | Permalink

JiscMail Tools


RSS Feeds and Sharing


Advanced Options


Archives

March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007


WWW.JISCMAIL.AC.UK

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager