159 research outputs found
Biomarkers of Aryl-hydrocarbon Receptor Activity in Gulf Killifish (Fundulus grandis) From Northern Gulf of Mexico Marshes Following the Deepwater Horizon Oil Spill
© 2017, Springer Science+Business Media New York. Following the Deepwater Horizon oil spill, shorelines throughout the Barataria Basin of the northern Gulf of Mexico in Louisiana were heavily oiled for months with Macondo-252 oil, potentially impacting estuarine species. The Gulf killifish (Fundulus grandis) has been identified as a sentinel species for the study of site-specific effects of crude oil contamination on biological function. In November and December 2010, 4–5 months after the Macondo well was plugged and new oil was no longer spilling into the Gulf waters, Gulf killifish were collected across the Barataria Basin from 14 sites with varying degrees of oiling. Fish collected from oiled sites exhibited biological indications of exposure to oil, including increase in cytochrome P4501A (CYP1A) mRNA transcript and protein abundances in liver tissues. Immunohistochemistry revealed increases in gill, head kidney, and intestinal CYP1A protein at heavily oiled sites. Intestinal CYP1A protein was a sensitive indicator of exposure, indicating that intestinal tissue plays a key role in biotransformation of AHR ligands and that ingestion is a probable route of exposure, warranting additional consideration in future studies
Composite boson dominance in many-fermion systems
I recently proposed a method of bosonization based on the use of coherent
states of fermion composites, whose validity was restricted to smooth structure
functions. In the present paper I remove this limitation and derive results
which hold for arbitrary interactions and structure functions. The method
respects all symmetries and in particular fermion number conservation. It
reproduces exactly the results of the pairing model of atomic nuclei and of the
BCS model of superconductivity in the number conserving form of the
quasi-chemical equilibrium theory.Comment: 5 pages, no figur
Duality in the Color Flavor Locked Spectrum
We analyze the spectrum of the massive states for the color flavor locked
phase (CFL) of QCD. We show that the vector mesons have a mass of the order of
the color superconductive gap . We also see that the excitations
associated with the solitonic sector of the CFL low energy theory have a mass
proportional to and hence are expected to play no role for
the physics of the CFL phase for large chemical potential. Another interesting
point is that the product of the soliton mass and the vector meson mass is
independent of the gap. We interpret this behavior as a form of electromagnetic
duality in the sense of Montonen and Olive. Our approach for determining the
properties of the massive states is non-perturbative in nature and can be
applied to any theory with multiple scales.Comment: RevTeX4, 4 page
Color Superconductivity in Asymmetric Matter
The influence of different chemical potential for different flavors on color
superconductivity is analyzed.
It is found that there is a first order transition as the asymmetry grows.
This transition proceeds through the formation of bubbles of low density,
flavor asymmetric normal phase inside a high density, superconducting phase
with a gap {\it larger} than the one found in the symmetric case. For small
fixed asymmetries the system is normal at low densities and superconducting
only above some critical density. For larger asymmetries the two massless
quarks system stays in the mixed state for arbitrarily high densities.Comment: 8 pages, 2 figure
Superconductivity from perturbative one-gluon exchange in high density quark matter
We study color superconductivity in QCD at asymptotically large chemical
potential. In this limit, pairing is dominated by perturbative one-gluon
exchange. We derive the Eliashberg equation for the pairing gap and solve this
equation numerically. Taking into account both magnetic and electric gluon
exchanges, we find with ,
verifying a recent result by Son. For chemical potentials that are of physical
interest, GeV, the calculation ceases to be reliable quantitatively,
but our results suggest that the gap can be as large as 100 MeV.Comment: 19 pages, 6 figures. I accidentally replaced the paper with an
outdated version. This version has typos corrected and will appear in PR
Charged kaon condensation in high density quark matter
We show that at asymptotically high densities the ``color-flavor-locked +
neutral kaon condensate'' phase of QCD develops a {\it charged} kaon condensate
through the Coleman-Weinberg mechanism. At densities achievable in neutron
stars a charged kaon condensate forms only for some (natural) values of the low
energy constants describing the low-lying excitations of the ground state.Comment: 11 pages, 3 figures, new reference adde
Thermodynamics of the 3-flavor NJL model : chiral symmetry breaking and color superconductivity
Employing an extended three flavor version of the NJL model we discuss in
detail the phase diagram of quark matter. The presence of quark as well as of
diquark condensates gives raise to a rich structure of the phase diagram. We
study in detail the chiral phase transition and the color superconductivity as
well as color flavor locking as a function of the temperature and chemical
potentials of the system.Comment: 27 pages, 7 figure
Thermodynamics of two-colour QCD and the Nambu Jona-Lasinio model
We investigate two-flavour and two-colour QCD at finite temperature and
chemical potential in comparison with a corresponding Nambu and Jona-Lasinio
model. By minimizing the thermodynamic potential of the system, we confirm that
a second order phase transition occurs at a value of the chemical potential
equal to half the mass of the chiral Goldstone mode. For chemical potentials
beyond this value the scalar diquarks undergo Bose condensation and the diquark
condensate is nonzero. We evaluate the behaviour of the chiral condensate, the
diquark condensate, the baryon charge density and the masses of scalar diquark,
antidiquark and pion, as functions of the chemical potential. Very good
agreement is found with lattice QCD (N_c=2) results. We also compare with a
model based on leading-order chiral effective field theory.Comment: 24 pages, 12 figure
Charged and superconducting vortices in dense quark matter
Quark matter at astrophysical densities may contain stable vortices due to
the spontaneous breaking of hypercharge symmetry by kaon condensation. We argue
that these vortices could be both charged and electrically superconducting.
Current carrying loops (vortons) could be long lived and play a role in the
magnetic and transport properties of this matter. We provide a scenario for
vorton formation in protoneutron stars.Comment: Replaced with the published version. A typographical error in Eq. 2
is correcte
Dense quark matter in compact stars
The densest predicted state of matter is colour-superconducting quark matter,
in which quarks near the Fermi surface form a condensate of Cooper pairs. This
form of matter may well exist in the core of compact stars, and the search for
signatures of its presence is an ongoing enterprise. Using a bag model of quark
matter, I discuss the effects of colour superconductivity on the mass-radius
relationship of compact stars, showing that colour superconducting quark matter
can occur in compact stars at values of the bag constant where ordinary quark
matter would not be allowed. The resultant ``hybrid'' stars with colour
superconducting quark matter interior and nuclear matter surface have masses in
the range 1.3-1.6 Msolar and radii 8-11 km. Once perturbative corrections are
included, quark matter can show a mass-radius relationship very similar to that
of nuclear matter, and the mass of a hybrid star can reach 1.8 \Msolar.Comment: 11 pages, for proceedings of SQM 2003 conference; references added,
abstract reworde
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