The receiver operating characteristic (ROC) curve displays the capacity of a marker or diagnostic test to discriminate between two groups of subjects, cases versus controls. We present a comprehensive suite of Stata commands for performing ROC analysis. Non-parametric, semiparametric and parametric estimators are calculated. Comparisons between curves are based on the area or partial area under...

A long-standing observation in community ecology is that the scaling of species richness, as exemplified by species-area curves, differs on local and regional scales. This decoupling of scales may be largely due to sampling processes (the increasing constraint imposed by sampling fewer individuals at fine scales), as distinct from ecological processes, such as environmental heterogeneity, that ...

We introduce and study a Euclidean-invariant distance histogram function for curves. For a sufficiently regular plane curve, we prove that the cumulative distance histograms based on discretizing the curve by either uniformly spaced or randomly chosen sample points converge to our histogram function. Robustness of the curve histogram function under noise and pixelization of the curve is also es...

Objectives: The aims of this study were to test whether lightening of the overexposed radiographs improve determination of endodontic files length and whether lightened radiographs are comparable with ideally exposed radiographs. Material and Methods: Four dried human skull coated with soft tissue-equivalent wax used for exposing radiographs of the upper molars. First, the endodontic file was p...

measurement of chlorophyll fluorescence is noninvasive, highly sensitive, fast and easy way to give important information about the photosynthetic apparatus. chlorophyll fluorescence parameters and kautsky curves of wild oat and wild mustard sprayed by clodinafop and dicamba+2, 4-d respectively was investigated at two green house experiments. the results indicated significant reduction at trend...

various scaling methods such as relative viscosity, peclet and reynolds scaling were used to find the best scaling law. scaling and modeling of the flow curves of various model emulsions consist of tragacanth gum (tg) (0.5, 1 % wt), oleic acid (5, 10% v/v) and wpi (2, 4 % wt) were investigated and the best models were selected. as these emulsions are non-newtonian, they do not obey the usual, si...