Immunization for complex network based on the effective degree of vertex

The basic idea of many effective immunization strategies is first to rank the importance of vertices according to the degrees of vertices and then remove the vertices from highest importance to lowest until the network becomes disconnected. Here we define the effective degrees of vertex, i.e., the number of its connections linking to un-immunized nodes in current network during the immunization procedure, to rank the importance of vertex, and modify these strategies by using the effective degrees of vertices. Simulations on both the scale-free network models with various degree correlations and two real networks have revealed that the immunization strategies based on the effective degrees are often more effective than those based on the degrees in the initial network.Comment: 16 pages, 5 figure

catena-Poly[[[aqua­[3-(3-hy­droxy­phen­yl)prop-2-enoato]samarium(III)]-bis­[μ2-3-(3-hy­droxy­phen­yl)prop-2-enoato]] monohydrate]

The title SmIII compound, {[Sm(C9H7O3)3(H2O)]·H2O}n, was obtained under hydrothermal conditions. Its structure is isotypic with the analogous Eu complex. The latter was reported incorrectly in space group P1 by Yan et al. [J. Mol. Struct. (2008), 891, 298–304]. This was corrected by Marsh [Acta Cryst. B65, 782–783] to P-1. The SmIII ion is nine-coordinated by O atoms from one coordinating water molecule and the remaining ones from the 3-(3-hy­droxy­phen­yl)prop-2-enoatate anions (one bidentate, two bidentate and bridging, two monodentate bridging), leading to a distorted tricapped trigonal–prismatic coordination polyhedron surrounded by solvent water mol­ecules. In the crystal, extensive intermolecular O—H⋯O hydrogen-bonding inter­actions and π–π inter­actions [centroid–centroid separation = 3.9393 (1) Å] lead to the formation of a three-dimensional supra­molecular network

A New ZrCuSiAs-Type Superconductor: ThFeAsN

We report the first nitrogen-containing iron-pnictide superconductor ThFeAsN, which is synthesized by a solid-state reaction in an evacuated container. The compound crystallizes in a ZrCuSiAs-type structure with the space group P4/nmm and lattice parameters a=4.0367(1) {\AA} and c=8.5262(2) {\AA} at 300 K. The electrical resistivity and dc magnetic susceptibility measurements indicate superconductivity at 30 K for the nominally undoped ThFeAsN.Comment: 6 pages, 4 figures, 1 tabl