.\BSTR.\ CT A brief summary of the limited literature devoted to mud balls centers around nomenclature, the ideas regarding the origin of mud balls, and the factors limiting their size. A report is made of a combined field and laboratory study in which an investigaticn of the size which mud balls may attain leads to conclusions that differ from those in the literature; findings are presented wh...

We propose a class of rank-based procedures for testing that the shape matrix V of an elliptical distribution (with unspecified center of symmetry, scale, and radial density) has some fixed value V0; this includes, for V0 = Ik, the problem of testing for sphericity as an important particular case. The proposed tests are invariant under translations, monotone radial transformations, rotations, a...

Background: The seeds of some medicinal plants and their compounds have long been valued for their numerous health benefits. Objective:To investigate some physical and chemical properties of Salvia spp. Methods: Some physico-chemical properties in five species of Salvia seeds (consisted of S. officinalis L., S. macrosiphon L., S. hypoleuca L., S. sclarea L. and S. nemorosa L.) were measured ...

We investigated the effects of violations of the sphericity assumption on Type I error rates for different methodical approaches of repeated measures analysis using a simulation approach. In contrast to previous simulation studies on this topic, up to nine measurement occasions were considered. Effects of the level of inter-correlations between measurement occasions on Type I error rates were c...

between-subjects (groups) factor A with j=1,...,p levels and nj observations at each j and a single within-subjects (occasions) factor B with k=1,...,q levels is very frequent in almost all scientific fields (Shoukri & Pause, 1999). Although the nature of these designs is typically multivariate, the effects of design (occasions main effect and groups x occasions interaction) can be tested by us...

Porous and hollow particles are widely used in pharmaceuticals, as solid phases for chromatography, as catalyst supports, in bioanalytical assays and medical diagnostics, and in many other applications. By controlling size, shape, and chemistry, it is possible to tune the physical and chemical properties of the particles. In some applications of millimeter-scale hollow shells, such as in high e...