1,721,053 research outputs found
Anisotropic Expansion of the Universe and Generation of Quantum Interference in Light Propagation
No full textWe investigate the electrodynamic in a Bianchi type I cosmological model. This scenario reveals the possibility that photons, during their traveling, can make quantum interference. This effect is only due to the presence of two different axes of expansion in the cosmic evolution. In other word, it is possible to conclude that a purely metrical - or, equivalently, gravitational - phenomenon gives rise up to a quantum effect that manifests itself in the light propagation
Inhomogeneous and anisotropic Universe and apparent acceleration
No full textIn this paper, we introduce a Lemaître-Tolman-Bondi (LTB) Bianchi type I (plane symmetric) model of the Universe. We study and solve Einstein field equations. We investigate the effects of such a model of the Universe; in particular, these results are important in understanding the effect of the combined presence of an inhomogeneous and anisotropic universe. The observational magnitude-redshift data deviated from the UNION 2 catalog have been analyzed in the framework of this LTB anisotropic universe, and the fit has been achieved without the inclusion of any dark energy
Breeding for drought stress tollerance in durum wheath and Dasypyrum villosum (L.) Candargy
No full textUtilizzazione di un contraccettivo a basso dosaggio contenente Gestodene in premenopasua
No full textδN formalism on the past light-cone
No full textWe apply the gradient expansion approximation to the light-cone gauge, obtaining a separate universe picture at non-linear order in perturbation theory within this frame-work. Thereafter, we use it to generalize the delta Nformalism in terms of light-cone perturbations. As a consistency check, we demonstrate the conservation of the gauge invariant curvature perturbation on uniform density hypersurface zeta at the completely non-linear level. The approach studied provides a self-consistent framework to connect at non-linear level quantities from the primordial universe, such as zeta, written interms of the light-cone parameters, to late time observables
Cosmic Acceleration and f (R) Theory: Perturbed Solution in a Matter FLRW Model
No full textIn the present paper we consider f (R) gravity theories in the metric approach and we derive the equations of motion, focusing also on the boundary conditions. In such a way we apply the general equations to a first order perturbation expansion of the Lagrangian. We present a model able to fit supernovae data without introducing dark energy
Regularity and energy transfer for a nonlinear beam equation
No full textIn this paper we study some key effects of a discontinuous forcing term in a fourth order wave equation on a bounded domain, modeling the adhesion of an elastic beam with a substrate through an elastic-breakable interaction. By using a spectral decomposition method we show that the main effects induced by the nonlinearity at the transition from attached to detached states can be traced in a loss of regularity of the solution and in a migration of the total energy through the scales
Genotypic variability in abscisic acid accumulation in vitro NaCl stressed Vitis vinifera cultivars. International Symposium on: “Irrigation and water relations in grapevine and fruit trees”
No full textUtilizzazione di un contraccettivo a basso dosaggio contenente Gestodene in premenopasua
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