1,721,527 research outputs found
Matter collineations of Bianchi V spacetime
Full text linkMatter collineations of the Bianchi V spacetime are studied according to degenerate or non-degenerate energy-momentum tensor. We have found that in degenerate case there are infinitely many matter collineations, whereas two cases give finite number of matter collineations which are five and six. When the energy-momentum tensor is non-degenerate, we obtain either four, five, six or seven independent matter collineations, out of which three are minimal Killing vectors and the rest are proper matter collineations
Bianchi v brane-world cosmology with a generalized chaplygin gas
No full textIn the context of brane cosmology, we investigate exact solution of the gravitational field equations in the Randall-Sundrum model for an anisotropic brane with Bianchi V geometry, with a generalized Chaplygin gas, which plays the role of dark energy and interacts with dark matter particles. Also, the behavior of the observationally important parameters like expansion and anisotropy is examined
Averaging generalized scalar field cosmologies IV: locally rotationally symmetric Bianchi V model
No full textThis research focuses on scalar field cosmologies with a generalized harmonic potential. Our attention is centred on the anisotropic LRS Bianchi I and III metrics, Bianchi V metrics, and their isotropic limits. We provide a comprehensive overview of the first two metrics classes and offer new findings for Bianchi V metrics. We show that the Hubble parameter is a time-dependent perturbation parameter that controls the magnitude of the error between full-system and time-averaged solutions as it decreases, such that those complete and time-averaged systems have the same asymptotic behaviour. Therefore, oscillations entering the system can be controlled and smoothed out, simplifying the problem
Perturbations in Bianchi-V Spacetimes with Varying Λ, G and Viscous Fluids
No full textAs a follow-up of a recent article in which we investigated the cosmological background expansion history of the universe in Bianchi type-V cosmological models with bulk viscous fluid and evolving cosmological Λ and Newtonian G parameters, we study the evolution of the cosmological perturbations in the current work. In particular, we analyse the evolution of the viscous matter over-density that leads to formation of large-scale structures in the Bianchi-V model, and compare the results with standard ΛCDM solutions. Our results suggest that introducing viscous fluid in the background described by Bianchi-V geometry with evolving Λ and G amplifies the structure-growth rate
Ricci collineations in perfect fluid Bianchi V spacetime
Full text linkThe Bianchi V spacetimes with perfect-fluid matter are classified according to their Ricci collineations. We have found that in the degenerate case there are infinitely many Ricci collineations whereas a subcase gives a finite number of Ricci collineations which are five. In the non-degenerate case the group of Ricci collineations is finite, i.e. four or five or six or seven. Also, all results obtained satisfy the energy conditions
Spelling Out Focus-Fronting Chains and Wh-Chains: The Case of Italian
No full textThis article tackles the optionality of focus fronting in Italian in terms of alternative spellout of the highest or lowest link of a movement chain. The two options are equally optimal in that the highest link satisfies Scope Transparency while the lowest link, bearing [focus] and attracting the nuclear pitch accent, satisfies Rightmostness; on the other hand, spellout of intermediate chain links satisfies neither principle, and it is therefore suboptimal. As for interrogative wh-chains, it is argued that Rightmostness is nonapplicable, because in Italian the lowest link of the wh-chain does not possess the [focus] feature; consequently, Scope Transparency always selects the highest chain link as the optimal spellout option
Averaging generalized scalar field cosmologies IV: locally rotationally symmetric Bianchi V model
Full text linkThis research focuses on scalar field cosmologies with a generalized harmonic
potential. Our attention is centred on the anisotropic LRS Bianchi I and III
metrics, Bianchi V metrics, and their isotropic limits. We provide a
comprehensive overview of the first two metrics classes and offer new findings
for Bianchi V metrics. We show that the Hubble parameter is a time-dependent
perturbation parameter that controls the magnitude of the error between
full-system and time-averaged solutions as it decreases, such that those
complete and time-averaged systems have the same asymptotic behaviour.
Therefore, oscillations entering the system can be controlled and smoothed out,
which simplifies the problem at hand.Comment: Research Program Averaging Generalized Scalar Field Cosmologies, part
IV. 40 pages, 4 compound figures. Updated reference
"Is Topic a Root Phenomenon?"
No full textIn this paper we discuss the question of whether topics are
necessarily restricted to root clauses. From an interface perspective, if topics
affect the management of the conversational common ground (Reinhart 1981;
Büring 2003; Krifka 2007), we expect them to appear in clauses endowed
with illocutive force, implementing a conversational move (§ 2). This
conclusion, however, is too general. Adopting the typology of topics by
Frascarelli & Hinterhölzl (2007), we show (§ 3) that Familiar topics do not
affect the conversational dynamics, and as expected, they are not restricted
to root clauses. The English-Romance asymmetry in the distribution of
topics (Haegeman 2004) is reduced to the lack of Familiar topics in English,
as opposed to Romance. In § 4 we discuss English contrastive topics,
showing that they have embedded interpretations in non-asserted
complement clauses: we therefore sketch a semantic analysis which does not
link contrastive topics to conversational strate..
Bianchi V I_0 Universe with Magnetized Strange Quark Matter in f(R, T) Theory
No full textThis study discusses f(R, T) theory, one of the alternative theories. It\rthen studies magnetized strange quark matter in the universe model Bianchi V I0,\rhomogeneous and anisotropic. Afterwards, it has determined whether the energy\rconditions are provided by using the deceleration parameter while obtaining the solutions.\rMoreover, the evolution of the cosmic universe is examined with the help of\rgraphics and tables
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