Re: [ccp4bb] Highest shell standards

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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Subject: Re: Nature policy update regarding source code
From: Ian Tickle I {- dot -} Tickle {- at -} ASTEX-THERAPEUTICS {- dot -} COM
Date: 2007-03-26

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From: artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU
Date: 2007-03-26

Subject: Re: Highest shell standards
From: Michel Fodje michel {- dot -} fodje {- at -} LIGHTSOURCE {- dot -} CA
Date: 2007-03-26

You are probably referring to the following works:

Caliandro et al, Acta Cryst. D61 (2005) 556-565
and Caliandro et al, Acta Cryst. D61 (2005) 1080-1087

in which they used density modification to calculate phases for
unmeasured reflections, and used the phases to extend the resolution by
calculating rough estimates unmeasured amplitudes. Using this technique
they actually could improve the electron density.

If I'm not mistaken, George Sheldrick has implemented this "Free Lunch"
algorithm in SHELXE.

/Michel

On Fri, 2007-03-23 at 08:05 -0800, Edward Berry wrote:
> If instead you allow the missing F's
> to "float", calculating them on each cycle from the previous map
> using the fillin option, someone has shown (don't have the
> reference handy at the moment) that the F's tend toward the true F's
> (in the case that they weren't really missing but omitted as part
> of the test).
>
> Ed

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Nature policy update regarding source code
From: Ian Tickle I {- dot -} Tickle {- at -} ASTEX-THERAPEUTICS {- dot -} COM
Date: 2007-03-26

Next message:
Subject: SHARP question
From: artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU
Date: 2007-03-26