2,223 research outputs found

    Asymmetric embedding in brane cosmology

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    We derive a system of cosmological equations for a braneworld with induced curvature which is a junction between several bulk spaces. The permutation symmetry of the bulk spaces is not imposed, and the values of the fundamental constants, and even the signatures of the extra dimension, may be different on different sides of the brane. We then consider the usual partial case of two asymmetric bulk spaces and derive an exact closed system of scalar equations on the brane. We apply this result to the cosmological evolution on such a brane and describe its various partial cases.Comment: 10 page

    Quantum effects, soft singularities and the fate of the universe in a braneworld cosmology

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    We examine a class of braneworld models in which the expanding universe encounters a "quiescent" future singularity. At a quiescent singularity, the energy density and pressure of the cosmic fluid as well as the Hubble parameter remain finite while all derivatives of the Hubble parameter diverge (i.e., H˙{\dot H}, H¹{\ddot H}, etc. →∞\to \infty). Since the Kretschmann invariant diverges (RiklmRiklm→∞R_{iklm}R^{iklm} \to \infty) at the singularity, one expects quantum effects to play an important role as the quiescent singularity is approached. We explore the effects of vacuum polarization due to massless conformally coupled fields near the singularity and show that these can either cause the universe to recollapse or, else, lead to a softer singularity at which HH, H˙{\dot H}, and H¹{\ddot H} remain finite while {\dddot H} and higher derivatives of the Hubble parameter diverge. An important aspect of the quiescent singularity is that it is encountered in regions of low density, which has obvious implications for a universe consisting of a cosmic web of high and low density regions -- superclusters and voids. In addition to vacuum polarization, the effects of quantum particle production of non-conformal fields are also likely to be important. A preliminary examination shows that intense particle production can lead to an accelerating universe whose Hubble parameter shows oscillations about a constant value.Comment: 19 pages, 3 figures, text slightly improved and references added. Accepted for publication in Classical and Quantum Gravit

    Daily Rates Deposit System in Cooperation with Prosperous Ms, PT. Kondur Psa

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    The number of members of cooperatives MS. Substantial Prosperous is one source offunds owned by the cooperative's money. but they are reluctant to keep their moneyin cooperative savings in the bank because the interest is higher. to improve existingservices, needs to make a new service that will satisfy the depositors, that is a dailyinterest savings with basically the same with the bank. because of the need forinformation quickly and accurately, we need a computer-based support system

    Observational constraints on interacting quintessence models

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    We determine the range of parameter space of Interacting Quintessence Models that best fits the recent WMAP measurements of Cosmic Microwave Background temperature anisotropies. We only consider cosmological models with zero spatial curvature. We show that if the quintessence scalar field decays into cold dark matter at a rate that brings the ratio of matter to dark energy constant at late times,the cosmological parameters required to fit the CMB data are: \Omega_x = 0.43 \pm 0.12, baryon fraction \Omega_b = 0.08 \pm 0.01, slope of the matter power spectrum at large scals n_s = 0.98 \pm 0.02 and Hubble constant H_0 = 56 \pm 4 km/s/Mpc. The data prefers a dark energy component with a dimensionless decay parameter c^2 =0.005 and non-interacting models are consistent with the data only at the 99% confidence level. Using the Bayesian Information Criteria we show that this exra parameter fits the data better than models with no interaction. The quintessence equation of state parameter is less constrained; i.e., the data set an upper limit w_x \leq -0.86 at the same level of significance. When the WMAP anisotropy data are combined with supernovae data, the density parameter of dark energy increases to \Omega_x \simeq 0.68 while c^2 augments to 6.3 \times 10^{-3}. Models with quintessence decaying into dark matter provide a clean explanation for the coincidence problem and are a viable cosmological model, compatible with observations of the CMB, with testable predictions. Accurate measurements of baryon fraction and/or of matter density independent of the CMB data, would support/disprove these models.Comment: 16 pages, Revtex4, 5 eps figures, to appear in Physical Review

    Making North Sulawesi Province Tourism Website Using Microsoft Word 2000

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    Making Tourism Website of North Sulawesi province using Microsoft Word 2000 isan application contains information about the surrounding WWWW North Sulawesi,the state geology, climate, unique wildlife around the North Sulawesi province areprotected, potential tourist attraction of North Sulawesi province are packed in anattractive form . Expected creation of this website can help users in finding additionalpages of information on North Sulawesi province.Using Microsoft Word 2000, this application is the combination of bits of the webpages are pictures, text animations, which are summarized into a single applicationthat is expected in the form of easy to use for anybody and made as attractive aspossible.By simply clicking a button from the menu options the user will immediately get theinformation quickly

    Local Semi Automatic Clearing System (Sokz) on Bank Xyz

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    In writing this paper the authors discuss the automatic system that existed at the localclearing of XYZ Bank. This system is used to provide good service to customers thanusing a local automated system which is efficient clearing but did not givesatisfaction in service to customers who have accounts at the bank. Both systemshave advantages and disadvantages of each, but the goal of every bank is to attract thecustomer's money as much as possible while providing good service so that the localclearing system semiotomasi more help service

    Statefinder diagnostic in a torsion cosmology

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    We apply the statefinder diagnostic to the torsion cosmology, in which an accounting for the accelerated universe is considered in term of a Riemann-Cartan geometry: dynamic scalar torsion. We find that there are some typical characteristic of the evolution of statefinder parameters for the torsion cosmology that can be distinguished from the other cosmological models. Furthermore, we also show that statefinder diagnostic has a direct bearing on the critical points. The statefinder diagnostic divides the torsion parameter a1a_1 into differential ranges, which is in keeping with the requirement of dynamical analysis. In addition, we fit the scalar torsion model to ESSENCE supernovae data and give the best fit values of the model parameters.Comment: 18 pages, 15 figures, accepted paper in JCA

    Can the Chaplygin gas be a plausible model for dark energy?

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    In this note two cosmological models representing the flat Friedmann Universe filled with a Chaplygin fluid, with or without dust, are analyzed in terms of the recently proposed "statefinder" parameters. Trajectories of both models in the parameter plane are shown to be significantly different w.r.t. "quiessence" and "tracker" models. The generalized Chaplygin gas model with an equation of state of the form p=−A/ραp = -A/\rho^{\alpha} is also analyzed in terms of the statefinder parameters.Comment: 6 pages, 2 figure

    Induced cosmological constant and other features of asymmetric brane embedding

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    We investigate the cosmological properties of an "induced gravity" brane scenario in the absence of mirror symmetry with respect to the brane. We find that brane evolution can proceed along one of four distinct branches. By contrast, when mirror symmetry is imposed, only two branches exist, one of which represents the self-accelerating brane, while the other is the so-called normal branch. This model incorporates many of the well-known possibilities of brane cosmology including phantom acceleration (w < -1), self-acceleration, transient acceleration, quiescent singularities, and cosmic mimicry. Significantly, the absence of mirror symmetry also provides an interesting way of inducing a sufficiently small cosmological constant on the brane. A small (positive) Lambda-term in this case is induced by a small asymmetry in the values of bulk fundamental constants on the two sides of the brane.Comment: 17 pages, 4 figures. New results and two figures discussing transient acceleration are included. Version accepted for publication in JCA
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