Search

Prediction (regression) equations are widely used, but their reliability as predictive tools is questionable as they provide contradicting results. The key point is that values calculated by regression equations are not precisely defined numbers but lie within a range of possible values in the standard deviation interval, none of which can be considered as the most probable. Ignoring this point leads to illicit/improper calculations, generating wrong results, which may have adverse consequences for human health. To demonstrate this, we applied the equations of Harris and Benedict in a reverse method, i.e. calculating (predicting) the daily energy expenditure in the same subjects used to obtain the equations and comparing values with the original measured data. We used the Bland-Altman and frequency distribution analyses. We found large differences in both individual data and population characteristics, showing that prediction equations are not predictive tools. [ABSTRACT FROM AUTHOR]

Abstract: All known populations of the Sardinian endemic Centaurea filiformis Viv. (Asteraceae) were studied in order to understand the impact of both geographic and ecological factors on the genetic structuring of this species. Fourteen populations and 234 individuals were sampled. The demographic structure of the populations and the reproductive ecology were estimated in 28 plots. Population genetic analyses were based on SSR markers. Genetic structure was investigated by spatial Bayesian methods. Average densities of 0.51 individuals m−2 were detected, with a prevalence of adults. Ten species of pollinators were identified; C. filiformis ability to self‐pollinate and myrmecochory were demonstrated experimentally. The populations displayed an average heterozygosity value of He = 0.576 and high genetic differentiation (overall FST = 0.218). Bayesian analysis suggests that five is the most probable number of gene pools of origin. A strong correlation between geographic distances and genetic distances among populations was highlighted. The demographic population structure of C. filiformis is dominated by adults, suggesting that it is a stable‐regressive or senile species, investing more in local persistence than colonisation ability. Despite the scattered distribution, the populations studied do not present evidence of genetic erosion. The analysis of genetic differentiation reveals very high differentiation levels among populations, thus indicating that effective barriers exist against gene flow. A general conclusion is that population distribution results in a clear genetic structure for the populations studied, and that geography and not ecology is shaping the present distribution of this species. [ABSTRACT FROM AUTHOR]

AbstractThe routes through which Norway spruce recolonized the Alps after the last ice age were investigated at the genetic level. Seven populations along the Alpine range plus one Apennine population were characterized for seven sequence-characterized amplified region (SCAR) loci, detecting an overall FST = 0.118. This rather high value for forest species reflects an uneven distribution of genetic variability, and was analysed through different statistical methods. Alternative hypotheses were tested under the isolation-by-distance model and using the analysis of molecular variance (amova) frame. We conclude that the hypothesis of the existence of a glacial refugium in the Apennines should be rejected, while a putative relict population is identified in the Maritime Alps. The Alpine range of Norway spruce appears to be split in two parts across a north–south line. The results are discussed in comparison with data based on morphological markers, isozymes, chloroplast microsatellites and mitochondrial markers. [ABSTRACT FROM AUTHOR]