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The invasive ctenophore Mnemiopsis leidyi was first recorded in the Caspian Sea in 1995 in the southern part of the sea (Iranian waters). This study assesses the magnitude of the M. leidyi bioinvasion impacts on the region's ecosystem using the biopollution level (BPL) index. For this purpose, biomass and distribution range of the invasive ctenophore were analyzed for the period 1996-2010. In addition, the impacts of the IAS on native species, communities, habitats and ecosystem functioning were assessed. The BPL for the period of our study remained relatively stable at the level 4 (massive). The BPLs caused by M. Leidyi in the southern Caspian Sea were compared with those of the Black and Baltic Seas. The method used in this study seems to be applicable for evaluating spatial and temporal variations of the invasive impacts of gelatinous zooplankton in other marine regions. [ABSTRACT FROM AUTHOR]

In this paper, we present a method for solving national economies in state space with fractional order, we use the triangular function operational matrix of the fractional order integration to solve the fractional-order national economies equation. The method is described and illustrated with numerical simulation. Numerical simulations are given to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Matrices associated with symmetric and regular structures can be arranged into certain block patterns known as Canonical forms. Using such forms, the decomposition of structural matrices into block diagonal forms, is considerably simplified. In this paper the main canonical forms are reviewed; and symmetric/regular structural configurations that can be explained with such forms are investigated. The invariant subspaces are formulated and the closed form solutions for the block-diagonalized stiffness matrices are provided in each case. Utility and robustness of the canonical forms in the analysis of structures exhibiting decomposable matrix patterns are demonstrated by numerous examples. Furthermore, a numerical method is proposed to extend the computational advantages of the matrix canonical forms to other nonconforming regular structures. [ABSTRACT FROM AUTHOR]

Planar brushes formed by end-grafted semiflexible polyampholyte chains, each chain containing an equal number of positively and negatively charged monomers, are studied using molecular dynamics simulations. Keeping the length of the chains fixed, the dependences of the average brush thickness and equilibrium statistics of the brush conformations on the grafting density and the salt concentration are obtained with various sequences of charged monomers. When similarly charged monomers of the chains are arranged in longer blocks, the average brush thickness is smaller and the dependence of brush properties on the grafting density and the salt concentration is stronger. With such long blocks of similarly charged monomers, the anchored chains bond to each other in the vicinity of the grafting surface at low grafting densities and buckle toward the grafting surface at high grafting densities. [ABSTRACT FROM AUTHOR]

In this article the concept of graph coloration for factorization of the characteristic polynomial of a weighted directed graph is introduced and using the fundamental lemma of Petersdorf and Sachs, it is shown that this concept can be extended to other spectra of graph among which is the spectrum of the Laplacian matrix of graphs. The goal is to use this concept for factorizing the graphs having different types of symmetry properties. In order to present an efficient algorithm, some concepts from group theory are needed. The combination of group theory and graph coloration provides a powerful method for factorizing various structural matrices, an example of which is the stiffness matrices of mass-spring dynamic systems. [ABSTRACT FROM AUTHOR]