20,713 research outputs found
Understanding chemical evolution in resolved galaxies -- I The local star fraction-metallicity relation
This work studies the relation between gas-phase oxygen abundance and
stellar-to-gas fraction in nearby galaxies. We first derive the theoretical
prediction, and argue that this relation is fundamental, in the sense that it
must be verified regardless of the details of the gas accretion and star
formation histories. Moreover, it should hold on "local" scales, i.e. in
regions of the order of 1 kpc. These predictions are then compared with a set
of spectroscopic observations, including both integrated and resolved data.
Although the results depend somewhat on the adopted metallicity calibration,
observed galaxies are consistent with the predicted relation, imposing tight
constraints on the mass-loading factor of (enriched) galactic winds. The
proposed parametrization of the star fraction-metallicity relation is able to
describe the observed dependence of the oxygen abundance on gas mass at fixed
stellar mass. However, the "local" mass-metallicity relation also depends on
the relation between stellar and gas surface densities.Comment: 10 pages, 4 figures. Matches accepted version (significant typo
corrected
The Importance of Asymptotic Freedom for the Pseudocritical Temperature in Magnetized Quark Matter
Although asymptotic freedom is an essential feature of QCD, it is absent in
effective chiral quark models like the Nambu--Jona-Lasinio and linear sigma
models. In this work we advocate that asymptotic freedom plays a key role in
the recently observed discrepancies between results of lattice QCD simulations
and quark models regarding the behavior of the pseudocritical temperature
for chiral symmetry restoration in the presence of a magnetic
field . We show that the lattice predictions that decreases
with can be reproduced within the Nambu--Jona-Lasinio model if the coupling
constant of the model decreases with and the temperature. Without
aiming at numerical precision, we support our claim by considering a simple
ansatz for that mimics the asymptotic freedom behavior of the QCD coupling
constant for large values of .Comment: 5 pages, 4 figures. This version matches the published on
Development of casein micellar pediatric formulations
Poster presented at the 1st European Conference on Pharmaceutics. 13-14 April 2015, Reims, France."The current need for medicines specifically designed for children, which consider ease of administration, dose flexibility, palatability, safety of excipients, stability and therapeutic equivalency of pediatric dosage forms, has driven the development of pediatric drug formulations.
In the present work casein (CN) based micellar formulations are evaluated as vehicles for the oral delivery of pediatric drugs, since caseins are nontoxic, biodegradable, GRAS materials and nanoencapsulation of drugs can improve their bioavailability. Chemical crosslinking of casein by carbodiimide (EDC) has been studied as an approach to improve the stability of the CN micelles and to tailor drug release."Fundação para a Ciência e a Tecnologia, Portugal (Research grant PTDC/DTPFTO/1057/2012
Tanaka-Tagoshi Parametrization of post-1PN Spin-Free Gravitational Wave Chirps: Equispaced and Cardinal Interpolated Lattices For First Generation Interferometric Antennas
The spin-free binary-inspiral parameter-space introduced by Tanaka and
Tagoshi to construct a uniformly-spaced lattice of templates at (and possibly
beyond) order is shown to work for all first generation interferometric
gravitational wave antennas. This allows to extend the minimum-redundant
cardinal interpolation techniques of the correlator bank developed by the
Authors to the highest available order PN templates. The total number of 2PN
templates to be computed for a minimal match is reduced by a
factor 4, as in the 1PN case.Comment: 9 pages, 8 figures, 3 tables, accepted for publication in Phys. Rev.
Rejection Properties of Stochastic-Resonance-Based Detectors of Weak Harmonic Signals
In (V. Galdi et al., Phys. Rev. E57, 6470, 1998) a thorough characterization
in terms of receiver operating characteristics (ROCs) of stochastic-resonance
(SR) detectors of weak harmonic signals of known frequency in additive gaussian
noise was given. It was shown that strobed sign-counting based strategies can
be used to achieve a nice trade-off between performance and cost, by comparison
with non-coherent correlators. Here we discuss the more realistic case where
besides the sought signal (whose frequency is assumed known) further unwanted
spectrally nearby signals with comparable amplitude are present. Rejection
properties are discussed in terms of suitably defined false-alarm and
false-dismissal probabilities for various values of interfering signal(s)
strength and spectral separation.Comment: 4 pages, 5 figures. Misprints corrected. PACS numbers added. RevTeX
Thermodynamics and Phase Structure of the Two-Flavor Nambu--Jona-Lasinio Model Beyond Large-N_c
The optimized perturbation theory (OPT) method is applied to the
version of the Nambu--Jona-Lasinio (NJL) model both at zero and at finite
temperature and/or density. At the first nontrivial order the OPT exhibits a
class of 1/N_c corrections which produce nonperturbative results that go beyond
the standard large-N_c, or mean-field approximation. The consistency of the OPT
method with the Goldstone theorem at this order is established, and appropriate
OPT values of the basic NJL (vacuum) parameters are obtained by matching the
pion mass and decay constant consistently. Deviations from standard large-N_c
relations induced by OPT at this order are derived, for example, for the
Gell--Mann-Oakes-Renner relation. Next, the results for the critical quantities
and the phase diagram of the model, as well as a number of other
thermodynamical quantities of interest, are obtained with OPT and then
contrasted with the corresponding results at large N_c.Comment: 29 pages, 20 figures, revtex. Minor corrections. In press Phys. Rev.
A new species of killifish (Pisces, Cyprinodontidae) from the chilean Altiplano
Ce travail décrit #Orestia chungarensis n. sp., un poisson Cyprinodontidae du lac Chungara (Altiplano chilien). #O. chungarensis n. sp. est élancé à flancs gris et ventre blanc avec des bandes verticales marron sombre. Il est caractérisé par ses grands yeux, sa bouche petite et protactile, ses mandibules dirigées vers le haut et ses nageoires pectorales petites comportant peu de rayons. Il vit dans les herbiers de #Myriophyllumelatinoides des zones littorales peu profondes de la partie ouest du lac. Il se nourrit principalement d'Amphipodes et de Chironomidae. Par ses caractéristiques morphologiques, #O. chungarensis ressemble à #O. gracilis$. (Résumé d'auteur
P-248 Futility and utility of two-stage hepatectomy
Meeting abstract in the European-Society-for-Medical-Oncology (ESMO) 21st World Congress on Gastrointestinal Cancer.info:eu-repo/semantics/publishedVersio
Experimental realization of the Yang-Baxter Equation via NMR interferometry
The Yang-Baxter equation is an important tool in theoretical physics, with
many applications in different domains that span from condensed matter to
string theory. Recently, the interest on the equation has increased due to its
connection to quantum information processing. It has been shown that the
Yang-Baxter equation is closely related to quantum entanglement and quantum
computation. Therefore, owing to the broad relevance of this equation, besides
theoretical studies, it also became significant to pursue its experimental
implementation. Here, we show an experimental realization of the Yang-Baxter
equation and verify its validity through a Nuclear Magnetic Resonance (NMR)
interferometric setup. Our experiment was performed on a liquid state
Iodotrifluoroethylene sample which contains molecules with three qubits. We use
Controlled-transfer gates that allow us to build a pseudo-pure state from which
we are able to apply a quantum information protocol that implements the
Yang-Baxter equation.Comment: 10 pages and 6 figure
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