Detection limit of the method was 0.13 nmol/l, reference range 0.25 1.0 nmol/l, and total variation (sum of intra- and inter-assay variation) was 7%.
C-peptide was analysed by commercial RIA (MD315, Euro-Diagnostica AB, Malmö, Sweden), total variation (sum of intra-and inter-assay variations) 7%, reference range 0.25 1.0 nmol/l, detection limit 0.13 nmol/l.
Thereafter, averages of these proportions were calculated; to adjust for differences in changes over time, we weighted these averages by absolute variation per year of summed variation for all years.
Zach et al. [9] proposed an algorithm that can be understood as a minimization of Eq. (5), which is the sum of the total variation of flow field u= u,v) and an L1 attachment term: E_{Z}({mathbf{u}})=int_{Omega}|nabla {mathbf{u}}|+lambda|I(mathbf{x},n -I(mathbf{x}+{mathbf{u}},n -I|dA (5).
The P method optimizes the ratio of the total variation to the sum of the piecewise variations, with the pieces set by the behavior of the known cyclic gene Lfng, and the S method is based on a numerical assessment that is provably stable (see Materials and Methods - "Pattern Detection Methods").
For any data set, the total variation is the sum of the contributions of all the different sources of variation.
None of the two aforementioned works, however, studied differences between countries in the variation in the life span per se, since the within-country component of the total variation is simply a sum of variations within single countries and hence does not facilitate comparisons of this statistic across countries.
The three first FPC curves explain 86.6, 7.0 and 4.3% of the total variation in the residuals, respectively; in sum almost 98% of the observed variation.
Conversely, for changed-tissues MZDE genes, the sum of variation explained by the detected eQTLs was only half of their expression variation across the RILs (Table 4), and ranged from 10%to98%98 % (Additional file 24: Table S14).
The characteristics contributing most to the individual distinctiveness were mean pitch and the sum of variation in factor 1 and HNR and amplitude ratio in factor 2. The GLMM using the same variables as the DFA and additional factors for sex and age classified 83.3% of the individuals correctly.
