87,623 research outputs found

    Cohomology of D-complex manifolds

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    In order to look for a well-behaved counterpart to Dolbeault cohomology in D-complex geometry, we study the de Rham cohomology of an almost D-complex manifold and its subgroups made up of the classes admitting invariant, respectively anti-invariant, representatives with respect to the almost D-complex structure, miming the theory introduced by Li and Zhang (2009) in [20] for almost complex manifolds. In particular, we prove that, on a 4-dimensional D-complex nilmanifold, such subgroups provide a decomposition at the level of the real second de Rham cohomology group. Moreover, we study deformations of D-complex structures, showing in particular that admitting D-Kähler structures is not a stable property under small deformations

    Il regno di Aragona / descritto da D. Nicolo Cantelli geografo. Dato in luce da Domenico de Rossi... 1696; A. Barbey sc.

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    1 mapa. Publicat probablement dins: Mercurio geografico, ed. de Domenico de Rossi. Roma, 1647-c.1720.66 x 52 c

    Pyrazolo[3,4-c]isothiazole and isothiazolo[4,3-d]isoxazolederivatives as antifungal agents

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    Context: The diseases of plants and humans due to pathogenic fungi are increasing. Among the substances used tocombat fungi, the azoles are of primary interest, both in agricultural field both in health. To avoid fungal resistancephenomena, the synthesis and tests of new derivatives are necessary.Objective: This article discusses the synthesis and the antifungal activity of pyrazolo[3,4-c]isothiazole andisothiazolo[4,3-d]isoxazole derivatives against three fungi that are pathogenic only for plants and two fungi that areopportunistic in humans and plants.Materials and Methods: The compounds were prepared starting from 2-cyano-3-ethoxy-2-butenethioamide. Theantifungal activity of the compounds was determined by measuring the inhibition of growth of the fungi tested at20, 50, and 100 μg/mL in comparison with the controls.Results: Results demonstrated that several compounds were able to control the mycelial growth of the tested fungi,even if they showed different sensitivity to the different azole-derivatives. In general Magnaporthe grisea (T.T. Hebert)Yaegashi & Udagawa was the most sensitive fungus, being blocked almost entirely by 4-chloro derivative even at 20μg/mL, a concentration at which the reference commercial compound tricyclazole was nearly ineffective.Discussion and conclusion: These findings demonstrate that the pyrazolo[3,4-c]isothiazole derivatives have a widespectrum of activity on phytopathogenic and opportunistic fungi. In particular the 4-chloro derivative seems to havea great potential as new product to combat M. grisea in the agricultural field
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