381 research outputs found

    Psi-floor diagrams and a Caporaso-Harris type recursion

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    Floor diagrams are combinatorial objects which organize the count of tropical plane curves satisfying point conditions. In this paper we introduce Psi-floor diagrams which count tropical curves satisfying not only point conditions but also conditions given by Psi-classes (together with points). We then generalize our definition to relative Psi-floor diagrams and prove a Caporaso-Harris type formula for the corresponding numbers. This formula is shown to coincide with the classical Caporaso-Harris formula for relative plane descendant Gromov-Witten invariants. As a consequence, we can conclude that in our case relative descendant Gromov-Witten invariants equal their tropical counterparts.Comment: minor changes to match the published versio

    Tropical descendant Gromov-Witten invariants

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    We define tropical Psi-classes on the moduli space of rational tropical curves in R^2 and consider intersection products of Psi-classes and pull-backs of evaluations on this space. We show a certain WDVV equation which is sufficient to prove that tropical numbers of curves satisfying certain Psi- and evaluation conditions are equal to the corresponding classical numbers. We present an algorithm that generalizes Mikhalkin's lattice path algorithm and counts rational plane tropical curves satisfying certain Psi- and evaluation conditions.Comment: 33 pages, 14 Postscript figures; minor changes to fit the published versio

    National innovation systems of the economies of the northern Europe countries: experience, which is useful for Russia

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    In the present study, we performed the analysis of the experience of national innovation system'sdevelopment in the countries of the Northern Europe. Such experience regarding the stages and processes of the formation of the national innovation system can be useful for understanding the problems that Russian economy struggles in this area. Innovation is a competitive strength in the modern world, inextricably connected with the sustainable growth of the subject. If we understand the reasons of the success of the most prosperous countries, we can be able to shift this experience on to the functionality of the Russian innovation system

    Block-Goettsche invariants from wall-crossing

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    We show how some of the refined tropical counts of Block and Goettsche emerge from the wall-crossing formalism. This leads naturally to a definition of a class of putative q-deformed Gromov-Witten invariants. We prove that this coincides with another natural q-deformation, provided by a result of Reineke and Weist in the context of quiver representations, when the latter is well defined

    Enumerative aspects of the Gross-Siebert program

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    We present enumerative aspects of the Gross-Siebert program in this introductory survey. After sketching the program's main themes and goals, we review the basic definitions and results of logarithmic and tropical geometry. We give examples and a proof for counting algebraic curves via tropical curves. To illustrate an application of tropical geometry and the Gross-Siebert program to mirror symmetry, we discuss the mirror symmetry of the projective plane.Comment: A version of these notes will appear as a chapter in an upcoming Fields Institute volume. 81 page

    Анализ эффективности замены сетевых подогревателей на пластинчатые теплообменники на ООО «УК и ТС» г. Гурьевск

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    В выпускной квалификационной работе произведен анализ эффективности замены сетевых подогревателей на пластинчатые теплообменники в ЦТП с целью повышения экономичности работы предприятия. Выполнен тепловой, конструктоpский расчёты и выбор пластинчатых подогревателей. Представлен технико-экономический анализ эффективности замены сетевых подогревателей на пластинчатые теплообменники, определены экономические затраты на покупку оборудования и выполнение работ. Проанализированы рабочие места на предмет выявления основных опасностей, оценена степень воздействия их на человека и природную средуIn the final qualifying result, the efficiency analysis was paid for the analysis of the efficiency of the number of replacing the network sieves of heaters with plate heat exchangers in the TSC in order to increase the plate economy of the work of the enterprise. The thermal, constructional calculations are carried out and select the plate heaters. The technical and economic analysis of the efficiency of replacement of the network heaters by the coilers with the plate heat exchangers, Economic cleaning is determined costs for the purchase of hygienic equipment and works. Analyzed zagryanei workplaces in order to identify the excess of the main hazards is reduced and harmfulness, estimated by the degree of impact they are fully on human and natural critics environment

    Annual post-market environmental monitoring (PMEM) report on the cultivation of genetically modified maize MON 810 in 2014 from Monsanto Europe S.A.

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    Following a request from the European Commission, the Panel on Genetically Modified Organisms of the European Food Safety Authority (GMO Panel) assessed the annual post-market environmental monitoring (PMEM) report for the 2014 growing season of maize MON 810 provided by Monsanto Europe S.A. The GMO Panel concludes that the insect resistance monitoring data do not indicate a decrease in susceptibility of field Iberian populations of corn borers to the Cry1Ab protein over the 2014 season. However, as the methodology for insect resistance monitoring remained unchanged compared to previous PMEM reports, the GMO Panel reiterates its previous recommendations for improvement of the insect resistance management plan. The GMO Panel considers that the farmer alert system to report complaints regarding product performance could complement the information obtained from the laboratory bioassays, but encourages the consent holder to provide more information in order to be in a position to appraise its usefulness. The data on general surveillance activities do not indicate any unanticipated adverse effects on human and animal health or the environment arising from the cultivation of maize MON 810 cultivation in 2014. The GMO Panel reiterates its previous recommendations to improve the methodology for the analysis of farmer questionnaires and conduct of the literature review in future annual PMEM reports on maize MON 810. The GMO Panel urges the consent holder to consider how to make best use of the information recorded in national registers to optimise sampling for farmer questionnaires, and requests to continue reviewing and discussing relevant scientific publications on possible adverse effects of maize MON 810 on rove beetles. Also, the GMO Panel encourages relevant parties to continue developing a methodological framework to use existing networks in the broader context of environmental monitorin

    Birational cobordism invariance of uniruled symplectic manifolds

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    A symplectic manifold (M,ω)(M,\omega) is called {\em (symplectically) uniruled} if there is a nonzero genus zero GW invariant involving a point constraint. We prove that symplectic uniruledness is invariant under symplectic blow-up and blow-down. This theorem follows from a general Relative/Absolute correspondence for a symplectic manifold together with a symplectic submanifold. A direct consequence is that symplectic uniruledness is a symplectic birational invariant. Here we use Guillemin and Sternberg's notion of cobordism as the symplectic analogue of the birational equivalence.Comment: To appear in Invent. Mat

    Stability data, irregular connections and tropical curves

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    We study a class of meromorphic connections nabla(Z) on P^1, parametrised by the central charge Z of a stability condition, with values in a Lie algebra of formal vector fields on a torus. Their definition is motivated by the work of Gaiotto, Moore and Neitzke on wall-crossing and three-dimensional field theories. Our main results concern two limits of the families nabla(Z) as we rescale the central charge Z to RZ. In the R to 0 ``conformal limit'' we recover a version of the connections introduced by Bridgeland and Toledano Laredo (and so the Joyce holomorphic generating functions for enumerative invariants), although with a different construction yielding new explicit formulae. In the R to infty ``large complex structure" limit the connections nabla(Z) make contact with the Gross-Pandharipande-Siebert approach to wall-crossing based on tropical geometry. Their flat sections display tropical behaviour, and also encode certain tropical/relative Gromov-Witten invariants

    Potential effects of oilseed rape expressing oryzacystatin-1 (OC-1) and of purified insecticidal proteins on larvae of the solitary bee Osmia bicornis

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    Despite their importance as pollinators in crops and wild plants, solitary bees have not previously been included in non-target testing of insect-resistant transgenic crop plants. Larvae of many solitary bees feed almost exclusively on pollen and thus could be highly exposed to transgene products expressed in the pollen. The potential effects of pollen from oilseed rape expressing the cysteine protease inhibitor oryzacystatin-1 (OC-1) were investigated on larvae of the solitary bee Osmia bicornis (= O. rufa). Furthermore, recombinant OC-1 (rOC-1), the Bt toxin Cry1Ab and the snowdrop lectin Galanthus nivalis agglutinin (GNA) were evaluated for effects on the life history parameters of this important pollinator. Pollen provisions from transgenic OC-1 oilseed rape did not affect overall development. Similarly, high doses of rOC-1 and Cry1Ab as well as a low dose of GNA failed to cause any significant effects. However, a high dose of GNA (0.1%) in the larval diet resulted in significantly increased development time and reduced efficiency in conversion of pollen food into larval body weight. Our results suggest that OC-1 and Cry1Ab expressing transgenic crops would pose a negligible risk for O. bicornis larvae, whereas GNA expressing plants could cause detrimental effects, but only if bees were exposed to high levels of the protein. The described bioassay with bee brood is not only suitable for early tier non-target tests of transgenic plants, but also has broader applicability to other crop protection products
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