منابع مشابه
Phylogenetic k-Root and Steiner k-Root
Given a graph G = (V; E) and a positive integer k, the Phylogenetic k-Root Problem asks for a (unrooted) tree T without degree-2 nodes such that its leaves are labeled by V and (u; v) 2 E if and only if dT (u; v) k. If the vertices in V are also allowed to be internal nodes in T , then we have the Steiner k-Root Problem. Moreover, if a particular subset S of V are required to be internal nodes ...
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During Arabidopsis root development, a radial pattern of tissues is extended by the meristem. These tissues form continuous layers and recent data suggest that tissue continuity is instrumental for constraining the direction of signaling in a process termed channeling. In the ground tissue, fate-determining signals originate from contiguous cells of the same layer, possibly due to specific symp...
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ژورنال
عنوان ژورنال: Nature
سال: 1922
ISSN: 0028-0836,1476-4687
DOI: 10.1038/110058a0