ODESSA

About: ODESSA is a based out in . It is known for research contribution in the topics: Population & Stars. The organization has 8058 authors who have published 8092 publications receiving 63228 citations.

Rapa whelk controls demersal community structure off Zmiinyi Island, Black Sea

Abstract: Between 2004 and 2012, populations of Mediterranean mussel (Mytilus galloprovincialis) and rapa whelk (Rapana venosa) from the coastal waters of Zmiinyi Island (Black Sea) were assessed for distribution, abundance, size, and age characteristics. Compared to 2004–2005, the mussel bed cover in 2012 decreased by 75.6%, the maximum depth of occurrence reduced from 22–25 m to 10–12 m, and total biomass declined by 44.6%. There was a concurrent decrease in abundance of demersal fishes dependent upon mussels as prey. We concluded that the invasive rapa whelk has had a detrimental impact on this demersal ecosystem. The possible influence of the introduced ctenophore Mnemiopsis leidyi on the two mollusc’s populations has also been discussed.

Synthesis and structure of vinylporphyrin metal complexes and their copolymerization: Spectral luminescence properties of Zn copolymers in solution

Abstract: Vinylporphyrins containing one vinyl group at the pyrrole or benzene ring and their complexes with Cu2+ and Zn2+ have been obtained by the Wittig reaction. The compounds obtained were characterized by physicochemical methods. X-ray diffraction analysis of 5-(4-vinylphenyl)-10,15,20-triphenylporphyrin has been carried out. It is likely that the inclusion of the vinyl group is accompanied by weak electron effects on the macrocycles. The radical-induced copolymerization of meso-tetraphenylporphyrin monomers with the vinyl group in a benzene or pyrrole ring and their copper and zinc complexes with styrene and methacrylate was studied. Porphyrin comonomers decrease the overall polymerization rate and the number-average molecular weight of the products formed compared with the weight of polystyrene obtained under similar conditions. The main reasons for termination of chain growth by vinylporphyrins were revealed and some quantitative parameters of these reactions were obtained. IR and electronic absorption spectra of porphyrin-containing copolymers are discussed. According to the ESR spectra, the copper-containing centres in the copolymers are fairly remote from each other, and the metal-containing polymeric systems are magnetically dilute. The spectral luminescence properties of solutions of zinc 5-(4-vinylphenyl)-10,15,20-triphenylporphyrin–methyl methacrylate copolymers with various contents of porphyrin groups were studied. It was shown that a new long-wave band appears in the absorption spectra of the copolymers, the intensity of which depends on the copolymer composition, and the quantum yield of fluorescence decreases with increasing molar fraction of porphyrin groups.

Nonlinear Poisson-Boltzmann equation in spherical symmetry.

Abstract: The Poisson-Boltzmann problem in spherical symmetry has been considered using the distribution of a self-consistent potential around a charged grain in a thermal collisional plasma as an example. The qualitative patterns of all possible solutions have been presented and a study of their asymptotics has been carried out. It has been demonstrated that for large potentials it is possible to neglect the curvature of the grain surface and to use the solution of the plane problem. It has also been demonstrated that the electrical interaction of the grains is possible only at distances smaller than eight screening lengths.