منابع مشابه
Claws for thought
What are the early signs of use? There are no early signs. There are only obvious signs common to all long-term users. What can be spotted is the transition from non-user to addict (one episode is sufficient for diagnosis). For example, an early draft of a manuscript may read “We replicated and extended a classic finding within an established theoretical framework...”; a later SciagraTM-influen...
متن کاملGenus Distributions for Iterated Claws
We derive a recursion for the genus distributions of the graphs obtained by iteratively attaching a claw to the dipole D3. The minimum genus of the graphs in this sequence grows arbitrarily large. The families of graphs whose genus distributions have been calculated previously are either planar or almost planar, or they can be obtained by iterative single-vertex or single-edge amalgamation of s...
متن کاملDistance-regular graphs without 4-claws
We determine the distance-regular graphs with diameter at least 3 and c2 ≥ 2 but without induced K1,4-subgraphs.
متن کاملForbidden Pairs for Vertex-Disjoint Claws
Let k ≥ 4, and let H1, H2 be connected graphs with |V (Hi)| ≥ 3 for i = 1, 2. A graph G is said to be {H1, . . . , Hl}-free if none of H1, . . . , Hl is an induced subgraph of G. We prove that if there exists a positive integer n0 such that every {H1, H2}-free graph G with |V (G)| ≥ n0 and δ(G) ≥ 3 contains k vertex-disjoint claws, then {H1, H2} ∩ {K1,t | t ≥ 2} = ∅. Also, we prove that every K...
متن کاملConcealed weapons: erectile claws in African frogs.
Vertebrate claws are used in a variety of important behaviours and are typically composed of a keratinous sheath overlying the terminal phalanx of a digit. Keratinous claws, however, are rare in living amphibians; their microstructure and other features indicate that they probably originated independently from those in amniotes. Here we show that certain African frogs have a different type of c...
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ژورنال
عنوان ژورنال: Nature
سال: 1987
ISSN: 0028-0836,1476-4687
DOI: 10.1038/325487b0