605 research outputs found

    Shell Crossing Singularities in Quasi-Spherical Szekeres Models

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    We investigate the occurrence of shell crossing singularities in quasi-spherical Szekeres dust models with or without a cosmological constant. We study the conditions for shell crossing singularity both from physical and geometrical point of view and they are in agreement.Comment: 10 latex pages, RevTex style, no figure

    Variable Modified Chaplygin Gas and Accelerating Universe

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    In this letter, I have proposed a model of variable modified Chaplygin gas and shown its role in accelerating phase of the universe. I have shown that the equation of state of this model is valid from the radiation era to quiessence model. The graphical representations of statefinder parameters characterize different phase of evolution of the universe. All results presented in the letter concerns the case k=0k=0.Comment: 7 Latex pages, 5 figures, revtex styl

    The effect of Pressure in Higher Dimensional Quasi-Spherical Gravitational Collapse

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    We study gravitational collapse in higher dimensional quasi-spherical Szekeres space-time for matter with anisotropic pressure. Both local and global visibility of central curvature singularity has been studied and it is found that with proper choice of initial data it is possible to show the validity of CCC for six and higher dimensions. Also the role of pressure in the collapsing process has been discussed.Comment: 11 pages, 6 figures, RevTeX styl

    Holographic Dark Energy Scenario and Variable Modified Chaplygin Gas

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    In this letter, we have considered that the universe is filled with normal matter and variable modified Chaplygin gas. Also we have considered the interaction between normal matter and variable modified Chaplygin gas in FRW universe. Then we have considered a correspondence between the holographic dark energy density and interacting variable modified Chaplygin gas energy density. Then we have reconstructed the potential of the scalar field which describes the variable modified Chaplygin cosmology.Comment: 4 latex pages, no figures, RevTeX styl

    Density Evolution in the New Modified Chaplygin Gas Model

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    In this paper, we have considered new modified Chaplygin gas (NMCG) model which interpolates between radiation at early stage and ╬Ť\LambdaCDM at late stage. This model is regarded as a unification of dark energy and dark matter (with general form of matter). We have derived the density parameters from the equation of motion for the interaction between dark energy and dark matter. Also we have studied the evolution of the various components of density parameters.Comment: 6 Latex pages, 4 figures, RevTex styl

    Collapse Dynamics of a Star of Dark Matter and Dark Energy

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    In this work, we study the collapse dynamics of an inhomogeneous spherically symmetric star made of dark matter (DM) and dark energy (DE). The dark matter is taken in the form of a dust cloud while anisotropic fluid is chosen as the candidate for dark energy. It is investigated how dark energy modifies the collapsing process and is examined whether dark energy has any effect on the Cosmic Censorship Conjecture. The collapsing star is assumed to be of finite radius and the space time is divided into three distinct regions ╬ú\Sigma and V┬▒V^{\pm}, where ╬ú\Sigma represents the boundary of the star and VÔłĺ(V+)V^{-}(V^{+}) denotes the interior (exterior) of the star. The junction conditions for matching V┬▒V^{\pm} over ╬ú\Sigma are specified. Role of Dark energy in the formation of apparent horizon is studied and central singularity is analyzed.Comment: 13 page

    Anisotropic Dark Energy and the Generalized Second Law of Thermodynamics

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    We consider a Bianchi type II model in which anisotropic dark energy is interacting with dark matter and anisotropic radiation. With this scenario, we investigate the validity of the generalized second law of thermodynamics. It is concluded that the validity of this law depends on different parameters like shear, skewness and equation of state.Comment: 12 pages, accepted for publication in Phys. Scr. arXiv admin note: text overlap with arXiv:1008.0692 and arXiv:1106.241

    Emergent Universe with Exotic Matter in Brane World Scenario

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    In this work, we have examined the emergent scenario in brane world model for phantom and tachyonic matter. For tachyonic matter field we have obtained emergent scenario is possible for closed, open and at model of the universe with some restriction of potential. For normal scalar field the emergent scenario is possible only for closed model and the result is identical with the work of Ellis et al [2], but for phantom field the emergent scenario is possible for closed, open and at model of the universe with some restriction of potential

    Evaluation of French bean (Phaseolus vulgaris L.) genotypes for seed production

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    An experimental study was conducted during 2011/2012 and 2012/2013 at Horticulture Research Station, Mondouri, Bidhan Chandra Krishi Viswavidyalaya, Monhanpur, Nadia, West Bengal, India, to evaluate the performance of fourteen different bush type French bean genotypes for seed yield and to study varietal characterization based on plant morphology. The genotypes, studied under this experiment were namely, Abhay, Shillong Local-3, Arjun, Selection-9, Arka Anoop, Arka Komal, Badshah, Anupam, Arka Suvidha, Falguni, Sonali, Local, Victoria and Vaishnavi-264. From overall point of view of the outcome of the experiment, it has been revealed that genotype with relatively bolder seeds with more number of seeds per pod, and higher bearing capacity per plant generally gives higher seed yield. Among the genotypes under study, Arka Suvidha was the best one as it produced the highest seed yield (2180.92 kg/ha) and relatively good plant vigour and fairly high seed vigour index (2944.38). Falguni and Mohanpur Local also can be considered promising once for seed production point of view
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