38 research outputs found

    Symplectic Cobordism in Small Dimensions and a Series of Elements of Order Four

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    We present the structure of symplectic cobordism ring MSpMSp_{*} in dimensions up to 51 and give a construction of an infinite series of elements Γi\Gamma_i, i=1,3,4,... i=1, 3,4, ..., of order four in this ring, where dimΓi=8i+95\operatorname{dim} \, \Gamma_i=8i+95. The key element of the series is Γ1\Gamma_1 in dimension 103.Comment: 117 pages, 18 table

    Long-term observation of amphibian populations inhabiting urban and forested areas in Yekaterinburg, Russia

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    This article presents data derived from a 36 year-long uninterrupted observational study of amphibian populations living in the city and vicinity of Yekaterinburg, Russia. This area is inhabited by six amphibian species. Based on a degree of anthropogenic transformation, the urban territory is divided into five highly mosaic zones characterized by vegetation, temperature, and a distinctive water pollution profile. Population data is presented year-by-year for the number of animals, sex ratio, and species-specific fecundity including the number and quality of spawns for the following amphibian species: Salamandrella keyserligii, Rana arvalis, R. temporaria, Lissotriton vulgaris, and Pelophylax ridibundus. These data provide an excellent opportunity to assess an urban environment from an animal population-wide perspective, as well as revealing the forces driving animal adaptation to the anthropogenic transformation of habitats

    Calculation principles for a superconducting inductive FCL and a current-limiting transformer

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    We present general principles of the parameters calculation and application of two power devices: an inductive fault current limiter and a current-limiting transformer. Both the devices are based on the superconducting - normal state transition in a superconducting switching element magnetically coupled with a primary winding. The relationships between the design parameters of the devices and the limited current, losses and temperature in the superconducting element were investigated. It is shown that, in spite of similarity, the devices have distinctive features manifested in different depths of the fault current limitation. The case of performance of the superconducting winding in the form of HTS BSCCO hollow cylinders is analyzed. Basic parameters of the devices are evaluated for their application in 45 MVA power circuit. Problems of the transition into the normal state and recovery of the superconducting state in the switching element are discussed.Comment: 26 pages including 11 figures and 1 table, submitted to IEEE Transactions on Applied Superconductivit

    Mapping class groups and braid groups

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    On homological properties of singular braids

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