457,607 research outputs found
SUPPLY RESPONSE IN THE NORTHEASTERN FRESH TOMATO MARKET: COINTEGRATION AND ERROR CORRECTION ANALYSIS
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
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
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
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, . They include negative phantom energy with an
equation of state parameter , negative cosmological constant: ,
negative domain walls: , negative cosmic strings: , negative
mass: , negative radiation: and negative ultralight: .
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
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 , 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
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
Recent observations on Type-Ia supernovae and low density () 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' (). 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 . Noting that for stiff matter and for radiation; is for dark energy because is due to `deficiency of
stiff-nuclear-matter' and that this binding energy is ultimately released as
`radiation' contributing , making . When
dark energy is released free at , . But as on present day
at when radiation strength has diminished to , . 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
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