The nanocrystalline hydroxyfluorapatite (HFA) was synthesized by mechanosynthesis with a planetary ball mill (PM200). disc to jar speed ratio constant (equal 0.5). effect of different milling parameters such as grinding duration, balls number’s, initial powder mass and rotation were studied apprehend their effects on both the process grinding/mechanosynthesis synthesis HFA. Unlike previous stud...

Dynamic linear regression models are used widely in applied econometric research. Most applications employ autoregressive (AR) models, distributed lag (DL) or (ARDL) models. These however, perform poorly for data sets with unknown, complex nonlinear patterns. This paper studies and semiparametric extensions of the dynamic model explores two techniques to allow unknown forms nonlinearities funct...

BACKGROUND Although non-normal data are widespread in biomedical research, parametric tests unnecessarily predominate in statistical analyses. METHODS We surveyed five biomedical journals and - for all studies which contain at least the unpaired t-test or the non-parametric Wilcoxon-Mann-Whitney test - investigated the relationship between the choice of a statistical test and other variables ...

For estimating conditional survival functions, non-parametric estimators can be preferred to parametric and semi-parametric estimators due to relaxed assumptions that enable robust estimation. Yet, even when misspecified, parametric and semi-parametric estimators can possess better operating characteristics in small sample sizes due to smaller variance than non-parametric estimators. Fundamenta...