This bias is exacerbated by the convention that phases go from 0 to
360*
while amplitudes go from zero to Plus.
===================
Sorry, I doubt this! I believe it is just because of the wave's nature.
1) It is correct the convention is to use 0-360 or 0-2pi as the
phases/angles. However,
the angle could be A + n*360. Just for convenience, one circle is used.
2) On the other hand, amplitudes could be normalized to very limitedly
small ranges, e.g.,
0-F(000), 0-1, etc.
3) Changing amplitudes (on an shifting way) does not change the
results, when map is contoured
by sigma, you can bring it back. EXACTLY, PHASE, IN COMBINATION WITH
(H,K,L),
PLAY THE IMPORTANT ROLE WHICH CHANGES THE AMPLITUDES PERIODICALLY IN THE
CELL (XYZ) AND IN THE RANGE OF -AMP TO + AMP. In this regards, the
sign of amplitude is
less meaningful---very negative amplitude, for sure, will give very
positive density contribution at
some specific spots in the cell, just because of the phases.
Lijun Liu
Cardiovascular Research Institute
University of California, San Francisco
1700 4th Street, Box 2532
San Francisco, CA 94158
Phone: (415)514-2836
