3,087 research outputs found
Energy density fluctuations in Early Universe
The primordial nucleosinthesys of the element can be influenced by the
transitions of phase that take place after the Big Bang, such as the QCD
transition. In order to study the effect of this phase transition, in this work
we compute the time evolution of thermodynamical quantities of the early
universe, focusing on temperature and energy density fluctuations, by solving
the relevant equations of motion using as input the lattice QCD equation of
state to describe the strongly interacting matter in the early universe plasma.
We also study the effect of a primordial strong magnetic field by means of a
phenomenological equation of state. Our results show that small inhomogeneities
of strongly interacting matter in the early Universe are moderately damped
during the crossover.Comment: 4 pages, 2 figures. Talk given at Sventh European Summer School on
Experimental Nuclear Astrophysics, 15-27 September 2013, Santa Tecla (CT) -
Ital
Dielectric correction to the Chiral Magnetic Effect
We derive an electric current density in the presence of a magnetic
field and a chiral chemical potential . We show that has
not only the anomaly-induced term (i.e. Chiral Magnetic
Effect) but also a non-anomalous correction which comes from interaction
effects and expressed in terms of the susceptibility. We find the correction
characteristically dependent on the number of quark flavors. The numerically
estimated correction turns out to be a minor effect on heavy-ion collisions but
can be tested by the lattice QCD simulation.Comment: 4 pages, 1 figur
Critical Endpoint and Inverse Magnetic Catalysis for Finite Temperature and Density Quark Matter in a Magnetic Background
In this article we study chiral symmetry breaking for quark matter in a
magnetic background, , at finite temperature and quark chemical
potential, , making use of the Ginzburg-Landau effective action formalism.
As a microscopic model to compute the effective action we use the renormalized
quark-meson model. Our main goal is to study the evolution of the critical
endpoint, , as a function of the magnetic field strength, and
investigate on the realization of inverse magnetic catalysis at finite chemical
potential. We find that the phase transition at zero chemical potential is
always of the second order; for small and intermediate values of ,
moves towards small , while for larger it moves
towards moderately larger values of . Our results are in agreement with
the inverse magnetic catalysis scenario at finite chemical potential and not
too large values of the magnetic field, while at larger direct magnetic
catalysis sets in.Comment: 6 pages, 2 figure
Probing the QCD vacuum with an abelian chromomagnetic field: A study within an effective model
We study the response of the QCD vacuum to an external abelian chromomagnetic
field in the framework of a non local Nambu-Jona Lasinio model with the
Polyakov loop. We use the Lattice results on the deconfinement temperature of
the pure gauge theory to compute the same quantity in the presence of dynamical
quarks. We find a linear relationship between the deconfinement temperature
with quarks and the squared root of the applied field strength, , in
qualitative (and to some extent also quantitative) agreement with existing
Lattice calculations. On the other hand, we find a discrepancy on the
approximate chiral symmetry restoration: while Lattice results suggest the
deconfinement and the chiral restoration remain linked even at non-zero value
of , our results are consistent with a scenario in which the two
transitions are separated as is increased.Comment: 14 pages, 7 figures, RevTeX4. Published version, with enlarged
abstract and minor changes in the main tex
Short-Term Neurodevelopmental Outcome in Term Neonates Treated with Phenobarbital versus Levetiracetam: A Single-Center Experience
BACKGROUND: Phenobarbital (PB) has been traditionally used as the first-line treatment for neonatal seizures. More recently, levetiracetam (LEV) has been increasingly used as a promising newer antiepileptic medication for treatment of seizures in neonates. OBJECTIVES: The aim of our study was to compare the effect of PB vs. LEV on short-term neurodevelopmental outcome in infants treated for neonatal seizures. METHOD: This randomized, one-blind prospective study was conducted on term neonates admitted to the Neonatal Intensive Care Unit of S. Bambino Hospital, University Hospital "Policlinico-Vittorio Emanuele," Catania, Italy, from February 2016 to February 2018. Thirty term neonates with seizures were randomized to receive PB or LEV; the Hammersmith Neonatal Neurological Examination (HNNE) was used at baseline (T0) and again one month after the initial treatment (T1). RESULTS: We found a significantly positive HNNE score for the developmental outcomes, specifically tone and posture, in neonates treated with LEV. There was no significant improvement in the HNNE score at T1 in the neonates treated with PB. CONCLUSION: This study suggests a positive effect of levetiracetam on tone and posture in term newborns treated for neonatal seizures. If future randomized-controlled studies also show better efficacy of LEV in the treatment of neonatal seizures, LEV might potentially be considered as the first-line anticonvulsant in this age grou
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