54 research outputs found

    Paracomplete logics which are dual to the paraconsistent logics L3A and L3B

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    In 2016 Beziau, introduce a more restricted concept of paraconsistency, namely the genuine paraconsistency. He calls genuine paraconsistent logic those logic rejecting φ, ¬φ |- ψ and |- ¬(φ ∧ ¬φ). In that paper the author analyzes, among the three-valued logics, which of these logics satisfy this property. If we consider multiple-conclusion consequence relations, the dual properties of those above mentioned are: |- φ, ¬φ, and ¬(ψ ∨ ¬ψ) |- . We call genuine paracomplete logics those rejecting the mentioned properties. We present here an analysis of the three-valued genuine paracomplete logics

    Atypical angiotensin II receptors coupled to phosphoinositide turnover/calcium signalling in catfish hepatocytes

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    AbstractIn catfish (Ictalurus punctatus) hepatocytes angiotensin II induced an immediate increase in cytosolic Ca2+ concentration. Other angiotensin analogues also induced this effect including: human angiotensin II, fish angiotensin II, human angiotensin III, human angiotensin I, fish angiotensin I and saralasin. CGP 42112A induced a very small effect at the highest concentration tested and angiotensin IV was without effect. Angiotensin II also increased the resynthesis of phosphatidylinositol and the production of IP3. These physiological effects were not blocked by losartan (AT1-selective antagonist) or PD 123177 (AT2-selective antagonist).[125I]Angiotensin II bound to liver plasma membranes in a saturable fashion with high affinity (KD 2.7 nM) and a Bmax of 185 fmol/mg of protein. Binding competition experiments showed the following order of potency: human angiotensin II=fish angiotensin II>human angiotensin III≥human angiotensin I=fish angiotensin I. These sites were insensitive to losartan or PD 123177.The data indicate that the angiotensin II receptors expressed in catfish hepatocytes are coupled to the phosphoinositide turnover/calcium mobilization signal transduction pathway and are atypical receptors, i.e., pharmacologically distinct from mammalian AT1 and AT2 receptors

    A class of colliding waves in metric-affine gravity, nonmetricity and torsion shock waves

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    By using our recent generalization of the colliding waves concept to metric-affine gravity theories, and also our generalization of the advanced and retarded time coordinate representation in terms of Jacobi functions, we find a general class of colliding wave solutions with fourth degree polynomials in metric-affine gravity. We show that our general approach contains the standard second degree polynomials colliding wave solutions as a particular case.Comment: 13 pages, latex, to appear in J.Math.Phy

    Note on Scalar Fields Non-Minimally Coupled to (2+1)-Gravity

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    Scalar fields non--minimally coupled to (2+1)-gravity, in the presence of cosmological constant term, are considered. Non-minimal couplings are described by the term ζRΨ2\zeta R \Psi^2 in the Lagrangian. Within a class of static circularly symmetric space-times, it is shown that the only existing physically relevant solutions are the anti-de Sitter space-time for ζ=0\zeta=0, and the Martinez-Zanelli black hole for ζ=1/8\zeta=1/8. We obtain also two new solutions with non-trivial scalar field, for ζ=1/6\zeta=1/6 and ζ=1/8\zeta=1/8 respectively, nevertheless, the corresponding space-times can be reduced, via coordinate transformations, to the standard anti-de Sitter space.Comment: 5 pages, RevTe

    On the Schr\"odinger Equation for the Supersymmetric FRW Model

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    We consider a time-dependent Schr\"odinger equation for the Friedmann-Robertson-Walker (FRW) model. We show that for this purpose it is possible to include an additional action invariant under reparametrization of time. The last one does not change the equations of motion for the minisuperspace model, but changes only the constraint. The same procedure is applied to the supersymmetric case.Comment: 15 pages. Revtex. Accepted for publication in Phys. Lett.

    Generating Gowdy cosmological models

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    Using the analogy with stationary axisymmetric solutions, we present a method to generate new analytic cosmological solutions of Einstein's equation belonging to the class of T3T^3 Gowdy cosmological models. We show that the solutions can be generated from their data at the initial singularity and present the formal general solution for arbitrary initial data. We exemplify the method by constructing the Kantowski-Sachs cosmological model and a generalization of it that corresponds to an unpolarized T3T^3 Gowdy model.Comment: Latex, 15 pages, no figure

    Application of evolution strategies for the solution of an inverse problem in near-field optics

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    International audienceWe introduce an inversion procedure for the characterization of a nanostructure from near-field intensity data. The method proposed is based on heuristic arguments and makes use of evolution strategies for the solution of the inverse problem as a nonlinear constrained-optimization problem. By means of some examples we illustrate the performance of our inversion method. We also discuss its possibilities and potential applications

    Engineering colors in all-dielectric metasurfaces: metamodeling approach

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    International audienceIn this letter, we engineer the colors of all-dielectric metasurfaces by means of a meta-model based optimization approach. This algorithm combines heuristic optimization and neural networks to retrieve the metasurface’s optimal geometrical parameters that serve to reproduce a prescribed color. The metasurfaces were fabricated and experimentally validated through dark field optical microscope images. We present typical results for periodic arrays of nanoparticles with arbitrary cross section. The approach is well-suited for color reproduction and computationally inexpensive
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