27 research outputs found

    Atomic Force Microscopy of Structural-Mechanical Properties of Polyethylene Reinforced by Silicate Needle-Shaped Filler

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    The paper presents the results of experimental studies of polyethylene-based composites reinforced with silicate needle-shaped filler (palygorskite) of different mass fraction (0, 5, 10, and 15%). These composites are less flammable and fire toxic than unfilled polyethylene. The structure (size, shape, and agglomeration of filler) and local mechanical properties of composites in nonstretched and elongated states were investigated by AFM. In stretched samples palygorskite takes a wavy shape, and at extremely high elongation the filler is orthogonal to the axis of tension. The smooth surfaces of the samples, required for AFM, were prepared using the heating/cooling procedure

    The twisting procedure

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    New format (short monography), 93 pages, minor corrections, submitted versionThis paper provides a conceptual study of the twisting procedure, which amounts to create functorially new differential graded Lie algebras, associative algebras or operads (as well as their homotopy versions) from a Maurer--Cartan element. On the way, we settle the integration theory of complete pre-Lie algebras in order to describe this twisting procedure in terms of gauge group action. We give a criterion on quadratic operads for the existence of a meaningful twisting procedure of their associated categories of (homotopy) algebras. We also give a new presentation of the twisting procedure for operads \`a la Willwacher and we perform new homology computations of graph complexes

    Feeding of the Amphipod <i>Gammarus aequicauda</i> in the Presence of the Planktonic Cladoceran <i>Moina salina</i> and the Benthic Chironomid Larvae <i>Baeotendipes noctivagus</i>

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    The energy balance approach helps to understand the limits within which the ‘predator–prey’ relationship can form, but cannot explain the formation of trophic links in natural multispecies systems. A time balance approach to the study of feeding has been developed to complement it. In the hypersaline Lake Moynaki (Crimea) which has a simple food web, there is one omnivorous species, Gammarus aequicauda, and two abundant prey, planktonic Moina salina and benthic Baeotendipes noctivagus. The size of M. salina ranges from 1.0 to 1.2 mm, and the size of B. noctivagus larvae from 9.0 to 10.0 mm. In experiments, elements of time balance were evaluated during feeding of G. aequicauda in the presence of both prey species, i.e., the duration of time spent searching before capture, handling prey, and resting between attempts to eat a chironomid larva. In all experiments, G. aequicauda consumed both kinds of prey. The maximum predation rate of G. aequicauda on the smaller sized M. salina was limited by searching and handling time, but on the larger B. noctivagus it was limited by digestion time. Feeding solely on chironomid larvae may well satisfy the energy needs of G. aequicauda. However, the food ration of G. aequicauda may be 50% higher if it feeds in the presence of both prey species than if feeding only on chironomid larvae. The presence of chironomid larvae more than halved the consumption of M. salina, compared to when cladocerans were the only prey

    Generalized cohomological field theories in the higher order formalism

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    In the classical Batalin--Vilkovisky formalism, the BV operator Δ\Delta is a differential operator of order two with respect to the commutative product. In the differential graded setting, it is known that if the BV operator is homotopically trivial, then there is a tree level cohomological field theory induced on the homology; this is a manifestation of the fact that the homotopy quotient of the operad of BV algebras by Δ\Delta is represented by the operad of hypercommutative algebras. In this paper, we study generalized Batalin--Vilkovisky algebras where the operator Δ\Delta is of the given finite order. In that case, we unravel a new interesting algebraic structure on the homology whenever Δ\Delta is homotopically trivial. We also suggest that the sequence of algebraic structures arising in the higher order formalism is a part of a "trinity" of remarkable mathematical objects, fitting the philosophy proposed by Arnold in the 1990s.Comment: v3: further minor changes (several formulas corrected, the explanation of acyclicity of a Koszul-type complex made more precise

    A checklist of the flowering plants of Komi Republic (northeast of European Russia) and their representation in BOLD and GenBank databases

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    We presented the updated list of flowering plants (Angiosperms) of the Komi Republic that comprises 1211 taxa (including subspecies), 401 genera, and 80 families. This checklist based on the authors field collections data, materials from the Scientific Herbarium of the Institute of Biology of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences, published data and open-access databases. For each taxon of flowering plants, we provided a presence-absence checklist of nucleotide sequences (rbcL, matK, ITS2 and trnH-psbA) that is available in BOLD and GenBank databases of DNA barcode data. The presented dataset will promote the identification of potentially new species (including endemic taxa) for molecular taxonomy and including of new sequences into the global database of BOLD Systems using the regional flora as model object

    Água e mudanças climåticas

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    70 pages, main changes concern title/abstract/introduction, a construction of two maps of "forgetting points", and a new formality resultInternational audienceWe introduce and study several new topological operads that should be regarded as nonsymmetric analogues of the operads of little 2-disks, framed little 2-disks, and Deligne-Mumford compactifications of moduli spaces of genus zero curves with marked points. These operads exhibit all the remarkable algebraic and geometric features that their classical analogues possess; in particular, it is possible to define a noncommutative analogue of the notion of cohomological field theory with similar Givental-type symmetries. This relies on rich geometry of the analogues of the Deligne-Mumford spaces, coming from the fact that they admit several equivalent interpretations: as the toric varieties of Loday's realisations of the associahedra, as the brick manifolds recently defined by Escobar, and as the De Concini-Procesi wonderful models for certain subspace arrangements
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