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The superior efficiency of systematic sampling at all levels in stereological studies is emphasized and various commonly used ways of implementing it are briefly described. Summarizing recent theoretical and experimental studies a set of very simple estimators of efficiency are presented and illustrated with a variety of biological examples. In particular,(More)
In the present paper, we summarize and further develop recent reseach in the estimation of the variance of sterelogical estimators based on systematic sampling. In particular, it is emphasized that the relevant estimation procedure depends on the sampling density. The validity of the variance estimation is examined in a collection of data sets, obtained by(More)
A stereological estimator of the weighted mean volume of particles of arbitrary shape is described. This unbiased estimator is based on simple point-sampling of linear intercept lengths. The complete absence of shape assumptions effectively breaks the long-standing 'convexity-barrier': the only requirement here is that individual particles can be(More)
The optical rotator is an unbiased, local stereological principle for estimation of cell volume and cell surface area in thick, transparent slabs. The underlying principle was first described in 1993 by Kiêu & Jensen (J. Microsc. 170, 45-51) who also derived an estimator of length. In this study we further discuss the methods derived from this principle and(More)
A method for estimating the orientated rose of normal directions of a three-dimensional (3D) set Z from a digitization of Z, i.e. a voxel image, is presented. It is based on counts of informative configurations in n x n x n voxel cubes. An algorithm for finding all informative configurations is proposed and an estimation procedure is described in detail for(More)
This report deals with the reconstruction of the distribution of membrane thickness T from that of orthogonal length Lo, measured in random section planes. In such planes the membrane appears as a band and the linear distance from one of its boundaries perpendicular to the opposite one is the length of the orthogonal intercept. Using a membrane model, an(More)
The quantification of anisotropy--its main direction and the degree of dispersion around it--is desirable in numerous research fields dealing with physical structures. Conventional methods are based on the orientation of interface elements. The results of these methods do not always agree with perceived anisotropy, and anisotropic structures do not(More)
The nucleator is a well-established manual stereological method of estimating mean cell volume from observations on random cell transects through reference points of the cells. In this paper, we present an automated version of the nucleator that uses automatic segmentation of the boundaries of the cell transects. An expert supervises the process. If the(More)
In the present study the Hamilton Anxiety Scale (HAS), originally constructed for patients with neurotic anxiety, has been applied to patients with diagnosis of depressive disorders. The inter-rater reliability and homogeneity are evaluated and total scale score has been correlated to the Bech-Rafaelsen Melancholia Scale (BRMES). Twenty-two patients entered(More)