Deconfinement of neutron star matter within the Nambu-Jona-Lasinio model

We study the deconfinement transition of hadronic matter into quark matter under neutron star conditions assuming color and flavor conservation during the transition. We use a two-phase description. For the hadronic phase we use different parameterizations of a non-linear Walecka model which includes the whole baryon octet. For the quark matter phase we use an SU(3)_f Nambu-Jona-Lasinio effective model including color superconductivity. Deconfinement is considered to be a first order phase transition that conserves color and flavor. It gives a short-lived transitory colorless-quark-phase that is not in beta-equilibrium, and decays to a stable configuration in tau ~ tau_{weak} ~ 10^{-8} s. However, in spite of being very short lived, the transition to this intermediate phase determines the onset of the transition inside neutron stars. We find the transition free-energy density for temperatures typical of neutron star interiors. We also find the critical mass above which compact stars should contain a quark core and below which they are safe with respect to a sudden transition to quark matter. Rather independently on the stiffness of the hadronic equation of state (EOS) we find that the critical mass of hadronic stars (without trapped neutrinos) is in the range of ~ 1.5 - 1.8 solar masses. This is in coincidence with previous results obtained within the MIT Bag model.Comment: 10 pages, 2 figure

Portuguese: Corpora, coordination and agreement

This paper reports some results from a corpus study of Portuguese, and explores their implications for the analysis of agreement processes involving coordinate structures (CSs), especially as regards gender agreement withi

Pion condensation in quark matter with finite baryon density

The phase structure of the Nambu -- Jona-Lasinio model at zero temperature and in the presence of baryon- and isospin chemical potentials is investigated. It is shown that in the chiral limit and for a wide range of model parameters there exist two different phases with pion condensation. In the first, ordinary phase, quarks are gapped particles. In the second, gapless pion condensation phase, there is no energy cost for creating only $u$- or both $u$ and $d$ quarks, and the density of baryons is nonzero.Comment: 7 pages, 6 figures; two references adde

Thermal nonlocal Nambu--Jona-Lasinio model in the real time formalism

The real-time formalism at finite temperature and chemical potential for the nonlocal Nambu--Jona-Lasinio model is developed in the presence of a Gaussian covariant regulator. We construct the most general thermal propagator, by means of the spectral function. As a result, the model involves the propagation of massive quasiparticles. The appearance of complex poles is interpreted as a confinement signal, and in this case we have unstable quasiparticles with a finite decay width. An expression for the propagator along the critical line, where complex poles start to appear, is also obtained. A generalization to other covariant regulators is proposed.Comment: 9 pages, 5 figures, minor changes, to appear in Phys. Rev.

Quantum shutter approach to tunneling time scales with wave packets

The quantum shutter approach to tunneling time scales (G. Garc\'{\i }a-Calder\'{o}n and A. Rubio, Phys. Rev. A \textbf{55}, 3361 (1997)), which uses a cutoff plane wave as the initial condition, is extended in such a way that a certain type of wave packet can be used as the initial condition. An analytical expression for the time evolved wave function is derived. The time-domain resonance, the peaked structure of the probability density (as the function of time) at the exit of the barrier, originally found with the cutoff plane wave initial condition, is studied with the wave packet initial conditions. It is found that the time-domain resonance is not very sensitive to the width of the packet when the transmission process is in the tunneling regime.Comment: 6 page

Interpreting Guineagrass Behaviour Under Different Clipping, Nitrogen and Irradiance RegimesA

An increase in the photosynthetic rate of the remaining tissues or regrowth has been proposed to explain compensatory growth after defoliation. In fact, we observed this effect in guineagrass, but it was not solely related to higher stomatal conductance. Nitrogen and irradiance may influence this response in the field, interacting with clipping. The objective of this research was to determine if these factors alter photosynthesis of intensively clipped well-watered guineagrass. Plants grown in a soil mixture were placed in the shade and in full sunlight. After establishment, some plants in each irradiance were clipped monthly at 20-cm, and the others left unclipped . Half of the plants in each irradiance and clipping regime were extra fertilized monthly using urea. With the clipped-off tissue, leaf area was measured, oven dried and weighed to obtain biomass. Samples were selected to analyze soluble sugar, starch, and total non-structural carbohydrates (TNC). A factorial 22x4 in a split plot completely randomized design was used. With the residual plants, photosynthesis and stomatal conductance were measured. In the final harvest biomass data was also obtained and a completely randomized 23 factorial arrangement was applied. In the clipped-off tissues significant differences were found for the biomass increments due to the nitrogen treatments, but not to irradiance regimes. Leaf area was more responsive to irradiance. In full sunlight, residual biomass was greatest using extra fertilization, both in unclipped and clipped plants. Clipped plants had higher photosynthesis than unclipped ones in the sun, and extra urea decreased this effect. Shaded guineagrass showing lower photosynthesis were not affected by clipping. Extra nitrogen applied in the shade alter only unclipped plants. When residual biomass and the clipped off tissues were added together, it was seen that clipping decreased total yield. In full sun, nitrogen fertilization reduced photosynthesis and stomatal conductance and increased chlorophyll both in clipped and unclipped plants. Higher photosynthesis in these well-watered plants was related with higher stomatal conductance, and higher yield with extra nitrogen

The status of shark and ray fishery resources in the Gulf of California: applied research to improve management and conservation

Seasonal surveys were conducted during 1998–1999 in Baja California, Baja California Sur, Sonora, and Sinaloa to determine the extent and activities of artisanal elasmobranch fisheries in the Gulf of California. One hundred and forty–seven fishing sites, or camps, were documented, the majority of which (n = 83) were located in Baja California Sur. Among camps with adequate fisheries information, the great majority (85.7%) targeted elasmobranchs during some part of the year. Most small, demersal sharks and rays were landed in mixed species fisheries that also targeted demersal teleosts, but large sharks were usually targeted in directed drift gillnet or, to a lesser extent, surface longline fisheries. Artisanal fishermen were highly opportunistic, and temporally switched targets depending on the local productivity of teleost, invertebrate, and elasmobranch fishery resources. Major fisheries for small sharks ( 1.5 m, “tiburón”) were minor components of artisanal elasmobranch fisheries in Sonora and Sinaloa, but were commonly targeted during summer and early autumn in Baja California and Baja California Sur. The pelagic thresher shark (Alopias pelagicus) and silky shark (Carcharhinus falciformis) were most commonly landed in Baja California, whereas a diverse assemblage of pelagic and large coastal sharks was noted among Baja California Sur landings. Rays dominated summer landings in Baja California and Sinaloa, when elevated catch rates of the shovelnose guitarfish (Rhinobatos productus, 13.2 individuals/vessel/trip) and golden cownose ray (Rhinoptera steindachneri, 11.1 individuals/vesse/trip) primarily supported the respective fisheries. The Sonoran artisanal elasmobranch fishery was the most expansive recorded during this study, and rays (especially R. productus) dominated spring and summer landings in this state. Seasonal catch rates of small demersal sharks and rays were considerably greater in Sonora than in other surveyed states. Many tiburón populations (e.g., C. leucas, C. limbatus, C. obscurus, Galeocerdo cuvier) have likely been overfished, possibly shifting effort towards coastal populations of cazón and rays. Management recommendations, including conducting demographic analyses using available life history data, determining and protecting nursery areas, and enacting seasonal closures in areas of elasmobranch aggregation (e.g., reproduction, feeding), are proposed. Without effective, enforceable management to sustain or rebuild targeted elasmobranch populations in the Gulf of California, collapse of many fisheries is a likely outcome. (PDF contains 243 pages

Non-dissipative anomalous currents in 2D materials: the parity magnetic effect as an analog of the chiral magnetic effect

Anomalous electric currents along a magnetic field, first predicted to emerge during large heavy ion collision experiments, were also observed a few years ago in condensed matter environments, exploring the fact that charge carriers in Dirac/Weyl semi-metals exhibit a relativistic-like behavior. The mechanism through which such currents are generated relies on an imbalance in the chirality of systems immersed in a magnetic background, leading to the so-called chiral magnetic effect (CME). While chiral magnetic currents have been observed in materials in three space dimensions, in this work we propose that an analog of the chiral magnetic effect can be constructed in two space dimensions, corresponding to a novel type of intrinsic half-integer Quantum Hall effect, thereby also offering a topological protection mechanism for the current. While the 3D chiral anomaly underpins the CME, its 2D cousin is emerging from the 2D parity anomaly, we thence call it the parity magnetic effect (PME). It can occur in disturbed honeycomb lattices where both spin degeneracy and time reversal symmetry are broken. These configurations harbor two distinct gap-opening mechanisms that, when occurring simultaneously, drive slightly different gaps in each valley, establishing an analog of the necessary chiral imbalance. Some examples of promising material setups that fulfill the prerequisites of our proposal are also listed.Comment: 11 pages, 5 figure

Mejora de los datos satelitales de precipitación y temperatura en áreas con baja disponibilidad de estaciones meteorológicas: caso de estudio en Ancash, Perú

[EN] Rainfall and temperature variables play an important role in understanding meteorology at global and regional scales. However, the availability of meteorological information in areas of complex topography is difficult, as the density of weather stations is often very low. In this study, we focused on improving existing satellite products for these areas, using Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) data for rainfall and Modern Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) data for air temperature. Our objective was to propose a model that improves the accuracy and correlation of satellite data with observed data on a monthly scale during 2012-2017. The improvement of rainfall satellite data was performed using 4 regions: region 1 Santa (R1Sn), region 2 Marañón (R2Mr), region 3 Pativilca (R3Pt) and region 4 Pacific (R4Pc). For temperature, a model based on the use of the slope obtained between temperature and altitude data was used. In addition, the reliability of the TRMM, GPM and MERRA-2 data was analyzed based on the ratio of the mean square error, PBIAS, Nash-Sutcliffe efficiency (NSE) and correlation coefficient. The final products obtained from the model for temperature are reliable with R2 ranging from 0.72 to 0.95 for the months of February and August respectively, while the improved rainfall products obtained are shown to be acceptable (NSE≥0.6) for the regions R1Sn, R2Mr and R3Pt. However, in R4Pc it is unacceptable (NSE<0.4), reflecting that the additive model is not suitable in regions with low rainfall values.[ES] Las variables de precipitación y temperatura desempeñan un papel importante en la comprensión de la meteorología a escala global y regional. Sin embargo, disponer de información meteorológica en zonas de topografía compleja es difícil, ya que la densidad de estaciones meteorológicas suele ser muy baja. En este estudio, nos centramos en mejorar los productos satelitales existentes para estas zonas, empleando datos de la Tropical Rainfall Measuring Mission (TRMM) y Global Precipitation Measurement (GPM) para la precipitación y los datos Modern Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) para la temperatura. Nuestro objetivo fue proponer un modelo que mejore la precisión y la correlación de los datos satelitales con los datos observados a escala mensual durante el 2012-2017. La mejora de los datos satelitales de precipitación se realizó utilizando 4 regiones: región 1 Santa (R1Sn), región 2 Marañón (R2Mr), región 3 Pativilca (R3Pt) y región 4 Pacífico (R4Pc). En la temperatura se utilizó un modelo basado en el uso de la pendiente obtenida entre los datos de temperatura y altitud. Además, se analizó la fiabilidad de los datos TRMM, GPM y el MERRA-2 basándose en la relación del error cuadrático medio, PBIAS, la eficiencia de Nash-Sutcliffe (NSE) y el coeficiente de correlación. Los productos finales obtenidos del modelo para la temperatura son fiables, con R2 entre 0,72 y 0,95 para los meses de febrero y agosto, respectivamente, mientras que los productos mejorados de precipitación obtenidos son aceptables (NSE≥0,6) para las regiones R1Sn, R2Mr y R3Pt. Sin embargo, en R4Pc es inaceptable (NSE<0,4), lo que refleja que el modelo aditivo empleado no es adecuado para regiones con bajos valores de precipitación.The authors acknowledge the financial support from the CONCYTEC - World Bank Project “Improvement and Expansion of the National Science Technology and Technological Innovation System Services”; 8682-PE, through its executing unit FONDECYT [Contract N°23-2018-FONDECYT-BM-IADT-MU] of Permafrost Project and from the Newton-Paulet Fund and the NERC within the framework of the call E031-2018-01-NERC & Glacier Research, through its executing unit FONDECYT [Contract N°08-2019-FONDECYT] of PeruGROWS project. We thank Rafael Tauquino, Ciro Fernández and Ricardo Villanueva for providing the meteorological data from the Center for Environmental Research for Development (CIAD), Santiago Antunez de Mayolo National University (UNASAM).Villavicencio, EE.; Medina, KD.; Loarte, EA.; León, HA. (2022). Improved rainfall and temperature satellite dataset in areas with scarce weather stations data: case study in Ancash, Peru. Revista de Teledetección. (60):17-28. https://doi.org/10.4995/raet.2022.1690717286