r4215 - /branches/consistency_tests_1.3/docs/latex/consistency_tests.tex -- December 18, 2007 - 23:10

Author: semor
Date: Tue Dec 18 23:10:24 2007
New Revision: 4215

URL: http://svn.gna.org/viewcvs/relax?rev=4215&view=rev
Log:
Wrote a first draft of the consistency testing documentation.

Text was inspired from the docstring in the file 
maths_fns/consistency_tests.py (main 1.2 line).


Modified:
    branches/consistency_tests_1.3/docs/latex/consistency_tests.tex

Modified: branches/consistency_tests_1.3/docs/latex/consistency_tests.tex
URL: 
http://svn.gna.org/viewcvs/relax/branches/consistency_tests_1.3/docs/latex/consistency_tests.tex?rev=4215&r1=4214&r2=4215&view=diff
==============================================================================
--- branches/consistency_tests_1.3/docs/latex/consistency_tests.tex (original)
+++ branches/consistency_tests_1.3/docs/latex/consistency_tests.tex Tue Dec 
18 23:10:24 2007
@@ -1,9 +1,27 @@
 % Consistency testing.
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%%%%%%%%%%%%%%%%%%%%%
 
 \chapter{Consistency testing}
 \index{consistency testing|textbf}
 
-\textbf{\textit{Please write me!}}
 
-Until this chapter is written please look at the sample script 
\texttt{`consistency\_tests.py'}.
+
+In spin relaxation, datasets are often recorded at different magnetic 
fields. This is especially important when $R_2$ values are to be used since 
$\mu$s-ms motions contribute to $R_2$. This contribution being scaled 
quadratically with the strength of the magnetic field, recording at multiple 
magnetic fields helps extract it. Also, acquiring data at multiple magnetic 
fields allows overdetermination of the mathematical problems, e.g. in the 
model-free approach.
+
+Recording at multiple magnetic fields is a good practice. However, it can 
cause artifacts if those different datasets are inconsistent. Inconsistencies 
can originate from, inter alia, the sample or the acquisition. Sample 
variations can be linked to changes in temperature, concentration, pH, etc. 
Water suppression is the main cause of acquisition variations as it affect 
relaxation parameters (especially NOE) of exposed and exchangeable moieties 
(e.g. the NH moiety).
+
+It is thus a good idea to assess consistency of datasets acquired at 
different magnetic fields. For this purpose, three tests are implemented in 
relax. They are all based on the same principle : calculate a field 
independant value and compare it from one field to another.
+
+The three tests are :
+
+$J(0)$ : The spectral density at the zero frequency calculated using the 
reduced spectral density approach.
+
+$F_\eta$ : A consistency function proposed by Fushman D. et al. (1998) JACS, 
120: 10947-10952.
+
+$F_{R_2}$ : A consistency function proposed by Fushman D. et al. (1998) 
JACS, 120: 10947-10952.
+
+Different methods exist to compare tests values calculated from one field to 
another. These include correlation plots and histograms, and calculation of 
correlation, skewness and kurtosis coefficients.
+
+
+
+Until this chapter is completed written please look at the sample script 
\texttt{`consistency\_tests.py'}.