46,409 research outputs found
Triangles bridge the scales: Quantifying cellular contributions to tissue deformation
In this article, we propose a general framework to study the dynamics and
topology of cellular networks that capture the geometry of cell packings in
two-dimensional tissues. Such epithelia undergo large-scale deformation during
morphogenesis of a multicellular organism. Large-scale deformations emerge from
many individual cellular events such as cell shape changes, cell
rearrangements, cell divisions, and cell extrusions. Using a triangle-based
representation of cellular network geometry, we obtain an exact decomposition
of large-scale material deformation. Interestingly, our approach reveals
contributions of correlations between cellular rotations and elongation as well
as cellular growth and elongation to tissue deformation. Using this Triangle
Method, we discuss tissue remodeling in the developing pupal wing of the fly
Drosophila melanogaster.Comment: 26 pages, 18 figure
Non-convex regularization in remote sensing
In this paper, we study the effect of different regularizers and their
implications in high dimensional image classification and sparse linear
unmixing. Although kernelization or sparse methods are globally accepted
solutions for processing data in high dimensions, we present here a study on
the impact of the form of regularization used and its parametrization. We
consider regularization via traditional squared (2) and sparsity-promoting (1)
norms, as well as more unconventional nonconvex regularizers (p and Log Sum
Penalty). We compare their properties and advantages on several classification
and linear unmixing tasks and provide advices on the choice of the best
regularizer for the problem at hand. Finally, we also provide a fully
functional toolbox for the community.Comment: 11 pages, 11 figure
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