1,721,010 research outputs found
Analysing the Surface Morphology of Colorectal Polyps:Differential Geometry and Pit Pattern Prediction
Full text linkWe present an initial study analysing the surface morphology of colorectal polyps from optical projection tomography. The differential geometry of polyp surfaces, segmented using a level sets method, is explored in terms of local, multi-scale shape index and curvedness descriptors. A surface region of interest can be represented using histograms of these descriptors. An experiment is described investigating the ability to predict pit pattern categories from these histograms using support vector machines
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Finding Golgi Stacks in Electron Micrographs
Full text linkTransmission electron microscopy (EM) can acquire images in which a range of subcellular organelles are clearly resolved simultaneously. There exist mature stereology techniques for extracting quantitative specimen information from section-based EM images and such techniques have been adopted successfully for use in immuno-EM. A bottleneck preventing the application of these nanomorphomics methods to high throughput applications is the recognition of organelle structures. This papers addresses this issue for one important organelle, the Golgi apparatus. A support vector machine is trained as a local Golgi detector based on rotationally invariant features. The SVM output is used to drive a graph-cuts segmentation. The ability of the method to detect and segment Golgi stacks is evaluated on a set of 36 micrographs
Finding Golgi Stacks in Electron Micrographs
Full text linkTransmission electron microscopy (EM) can acquire images in which a range of subcellular organelles are clearly resolved simultaneously. There exist mature stereology techniques for extracting quantitative specimen information from section-based EM images and such techniques have been adopted successfully for use in immuno-EM. A bottleneck preventing the application of these nanomorphomics methods to high throughput applications is the recognition of organelle structures. This papers addresses this issue for one important organelle, the Golgi apparatus. A support vector machine is trained as a local Golgi detector based on rotationally invariant features. The SVM output is used to drive a graph-cuts segmentation. The ability of the method to detect and segment Golgi stacks is evaluated on a set of 36 micrographs
Detecting and Segmenting Nanodiscs in Immuno-Electron Micrographs
Full text linkNanodiscs are soluble nanoscale phospholipid bilayers with applications in drug delivery and the study of membrane proteins, for example. They can be imaged using electron microscopy, along with immunogold markers indicating locations of proteins of interest. We describe and evaluate methods for automatically detecting and segmenting nanodiscs in electron micrographs. The detection method modifies aspects of the Fast Radial Symmetry Transform to detect nanodiscs that exhibit approximate radial symmetry against noisy but predominantly lighter background. Detected nanodiscs are then segmented using radial active contours. Experiments on micrographs both with and without immunogold markers indicate promising detection and segmentation performance, and that information on nanodisc quantities, locations, size distributions, and co-location with proteins of interest could be extracted automatically
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Detecting and Segmenting Nanodiscs in Immuno-Electron Micrographs
Full text linkNanodiscs are soluble nanoscale phospholipid bilayers with applications in drug delivery and the study of membrane proteins, for example. They can be imaged using electron microscopy, along with immunogold markers indicating locations of proteins of interest. We describe and evaluate methods for automatically detecting and segmenting nanodiscs in electron micrographs. The detection method modifies aspects of the Fast Radial Symmetry Transform to detect nanodiscs that exhibit approximate radial symmetry against noisy but predominantly lighter background. Detected nanodiscs are then segmented using radial active contours. Experiments on micrographs both with and without immunogold markers indicate promising detection and segmentation performance, and that information on nanodisc quantities, locations, size distributions, and co-location with proteins of interest could be extracted automatically
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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