A plane tiling consisting of congruent copies of a shape is isohedral provided that for any pair of copies, there exists a symmetry of the tiling mapping one copy to the other. We give a O(n log2 n)-time algorithm for deciding if a polyomino with n edges can tile the plane isohedrally. This improves on the O(n18)-time algorithm of Keating and Vince and generalizes recent work by Brlek, Provença...

see Leor Halevi, Muhammad’s Grave: Death Rites and the Making of Islamic Society (New York: Columbia University Press, 2007). See also Jane Idleman Smith and Yvonne Yazbeck Haddad, The Islamic Understanding of Death and Resurrection (Albany: State University of New York Press, 1981). On twentiethcentury reformist movements and political debates there is a vast literature; see, e.g., Richard P. ...

The present study uses the B subunit of cholera toxin, a protein that binds specifically to ganglioside GM1, to examine the role of endogenous GM1 in the process of growth and differentiation of mouse neuroblastoma N18 cells. Binding of the B subunit to neuroblastoma N18 cells inhibited DNA synthesis with concomitant induction of differentiation. The B subunit induced pronounced morphological c...

Sindbis virus (SV) is an alphavirus that causes acute encephalomyelitis in mice. The outcome is determined by the strain of virus and by the age and genetic background of the host. The mortality rates after infection with NSV, a neurovirulent strain of SV, were as follows v: 81% (17 of 21) in BALB/cJ mice; 20% (4 of 20) in BALB/cByJ mice (P < 0.001); 100% in A/J, C57BL/6J, SJL, and DBA mice; an...

Two novel yttrium nitrides, YN6 and Y2N11, were synthesized by direct reaction between nitrogen at 100 GPa 3000 K in a laser-heated diamond anvil cell. High-pressure synchrotron single-crystal X-ray diffraction revealed that the crystal structures of Y2N11 feature unique organization atoms—a previously unknown anionic N18 macrocycle polynitrogen double helix, respectively. Density functional th...

We extend the (recently introduced) notion of k-convexity of a two-dimensional subset of the Euclidean plane to finite point sets. A set of n points is ∗Corresponding author. Email addresses: [email protected] (Oswin Aichholzer), [email protected] (Franz Aurenhammer), [email protected] (Thomas Hackl), [email protected] (Ferran Hurtado), [email protected] (Alexander Pilz), pedro.ramos@uah...