457,607 research outputs found

    SUPPLY RESPONSE IN THE NORTHEASTERN FRESH TOMATO MARKET: COINTEGRATION AND ERROR CORRECTION ANALYSIS

    Get PDF
    This paper reexamines supply response in the Northeastern fresh tomato market during the 1949-94 period by employing cointegration and error correction technique. It tests whether there has been a long-run equilibrium relationship between Northeastern production and a set of price and nonprice factors that influence it. Findings suggest that wage rate, imports from competing regions, and urban pressure have had significant negative impacts on regional production. The negative relationship between price and production may have resulted from the strong negative effects exerted by the nonprice factors.Demand and Price Analysis,

    Domain-Walls in Einstein-Gauss-Bonnet Bulk

    Full text link
    We investigate the dynamics of a d-dimensional domain wall (DW) in a d+1-dimensional Einstein-Gauss-Bonnet (EGB) bulk. Exact effective potential induced by the Gauss-Bonnet (GB) term on the wall is derived. In the absence of the GB term we recover the familiar gravitational and anti-harmonic oscillator potentials. Inclusion of the GB correction gives rise to a minimum radius of bounce for the Friedmann-Robertson-Walker (FRW) universe expanding with a negative pressure on the DW.Comment: 4 pages and 4 figures, to appear in PR

    Inflatonic Solitons In Running Mass Inflation

    Get PDF
    The inflaton condensate associated with a global symmetry can fragment into quasistable Q balls, provided the inflaton oscillations give rise to an effective equation of state with negative pressure. We study chaotic inflation with a running inflaton mass and show that, depending on the sign of the radiative mass correction, the process of fragmentation into inflatonic Q balls can actually take place even though no net charge exists. If the main decay channel of the Q ball is to fermions, the universe will be reheated slowly via surface evaporation.Comment: 13 pages, RevTeX, 12 postscript figures include

    An exposition on Friedmann Cosmology with Negative Energy Densities

    Full text link
    How would negative energy density affect a classic Friedmann cosmology? Although never measured and possibly unphysical, certain realizations of quantum field theories leaves the door open for such a possibility. In this paper we analyze the evolution of a universe comprising varying amounts of negative energy forms. Negative energy components have negative normalized energy densities, Ω<0\Omega < 0. They include negative phantom energy with an equation of state parameter w<−1w<-1, negative cosmological constant: w=−1w=-1, negative domain walls: w=−2/3w=-2/3, negative cosmic strings: w=−1/3w=-1/3, negative mass: w=0w=0, negative radiation: w=1/3w=1/3 and negative ultralight: w>1/3w > 1/3. Assuming that such energy forms generate pressure like perfect fluids, the attractive or repulsive nature of negative energy components are reviewed. The Friedmann equation is satisfied only when negative energy forms are coupled to a greater magnitude of positive energy forms or positive curvature. We show that the solutions exhibit cyclic evolution with bounces and turnovers.The future and fate of such universes in terms of curvature, temperature, acceleration, and energy density are reviewed. The end states are dubbed Big Crunch, Big Void, or Big Rip and further qualified as "Warped", "Curved", or "Flat", "Hot" versus "Cold", "Accelerating" versus "Decelerating" versus "Coasting". A universe that ends by contracting to zero energy density is termed "Big Poof." Which contracting universes "bounce" in expansion and which expanding universes "turnover" into contraction are also reviewed.Comment: Abridged version with minor correction

    Functions of State for Spinor Gas in General Relativity

    Full text link
    The energy momentum tensor of perfect fluid is a simplified but successful model in astrophysics. In this paper, assuming the particles driven by gravity and moving along geodesics, we derived the functions of state in detail. The results show that, these functions have a little correction for the usual thermodynamics. The new functions naturally satisfy the causal condition and consist with relativity. For the self potentials of the particles we introduce an extra function WW, which acts like negative pressure and can be used to describe dark matter. The results are helpful to understand the relation and interaction between space-time and matter.Comment: 13 pages, no figure. arXiv admin note: text overlap with arXiv:0708.296

    Negative electrostatic contribution to the bending rigidity of charged membranes and polyelectrolytes screened by multivalent counterions

    Full text link
    Bending rigidity of a charged membrane or a charged polyelectrolyte screened by monovalent counterions is known to be enhanced by electrostatic effects. We show that in the case of screening by multivalent counterions the electrostatic effects reduce the bending rigidity. This inversion of the sign of the electrostatic contribution is related to the formation of two-dimensional strongly correlated liquids (SCL) of counterions at the charged surface due to strong lateral repulsion between them. When a membrane or a polyelectrolyte is bent, SCL is compressed on one side and stretched on the other so that thermodynamic properties of SCL contribute to the bending rigidity. Thermodynamic properties of SCL are similar to those of Wigner crystal and are anomalous in the sense that the pressure, compressibility and screening radius of SCL are negative. This brings about substantial negative correction to the bending rigidity. For the case of DNA this effect qualitatively agrees with experiment.Comment: 8 pages, 2 figure

    Genesis of Dark Energy: Dark Energy as Consequence of Release and Two-stage Tracking Cosmological Nuclear Energy

    Full text link
    Recent observations on Type-Ia supernovae and low density (Ωm=0.3\Omega_{m} = 0.3) measurement of matter including dark matter suggest that the present-day universe consists mainly of repulsive-gravity type `exotic matter' with negative-pressure often said `dark energy' (Ωx=0.7\Omega_{x} = 0.7). But the nature of dark energy is mysterious and its puzzling questions, such as why, how, where and when about the dark energy, are intriguing. In the present paper the authors attempt to answer these questions while making an effort to reveal the genesis of dark energy and suggest that `the cosmological nuclear binding energy liberated during primordial nucleo-synthesis remains trapped for a long time and then is released free which manifests itself as dark energy in the universe'. It is also explained why for dark energy the parameter w=−2/3w = - {2/3}. Noting that w=1 w = 1 for stiff matter and w=1/3w = {1/3} for radiation; w=−2/3w = - {2/3} is for dark energy because "−1""-1" is due to `deficiency of stiff-nuclear-matter' and that this binding energy is ultimately released as `radiation' contributing "+1/3""+ {1/3}", making w=−1+1/3=−2/3w = -1 + {1/3} = - {2/3}. When dark energy is released free at Z=80Z = 80, w=−2/3w = -{2/3}. But as on present day at Z=0Z = 0 when radiation strength has diminished to δ→0\delta \to 0, w=−1+δ1/3=−1w = -1 + \delta{1/3} = - 1. This, thus almost solves the dark-energy mystery of negative pressure and repulsive-gravity. The proposed theory makes several estimates /predictions which agree reasonably well with the astrophysical constraints and observations. Though there are many candidate-theories, the proposed model of this paper presents an entirely new approach (cosmological nuclear energy) as a possible candidate for dark energy.Comment: 17 pages, 4 figures, minor correction
    • …
    corecore