Quantum transport efficiency and Fourier's law

We analyze the steady-state energy transfer in a chain of coupled two-level systems connecting two thermal reservoirs. Through an analytic treatment we find that the energy current is independent of the system size, hence violating Fourier's law of heat conduction. The classical diffusive behavior in Fourier's law of heat conduction can be recovered by introducing decoherence to the quantum systems constituting the chain. Implications of these results on energy transfer in biological light harvesting systems, and the role of quantum coherences and entanglement are discussed.Comment: 6 pages, 4 figure

La inflación subyacente en la economía española: estimación y metodología

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Development and Evaluation of qPCR Detection Method and Zn-MgO/Alginate Active Packaging for Controlling Listeria monocytogenes Contamination in Cold-Smoked Salmon

To answer to food industry requests to monitor the presence of L. monocytogenes in cold-smoked salmon samples and to extend their shelf-life, a qPCR protocol for the detection of L. monocytogenes, and an antibacterial active packaging reinforced with zinc magnesium oxide nanoparticles (Zn-MgO NPs) were developed. The qPCR allowed the sensitive and easy detection of L. monocytogenes in naturally contaminated samples, with specificity in full agreement with the standard methods. The halo diusion study indicated a high antibacterial eciency of 1 mg/mL Zn-MgO NPs against L. monocytogenes, while the flow cytometry showed only moderate cytotoxicity of the nanoparticles towards mammalian cells at a concentration above 1 mg/mL. Thus, the novel active packaging was developed by using 1 mg/mL of Zn-MgO NPs to reinforce the alginate film. Cold-smoked salmon samples inoculated with L. monocytogenes and air-packed with the Zn-MgO NPs-alginate nanobiocomposite film showed no bacterial proliferation at 4 C during 4 days. In the same condition, L. monocytogenes growth in control contaminated samples packed with alginate film alone. Our results suggest that Zn-MgO nanoparticles can extend the shelf-life of cold-smoked salmon samples

Modelado del NO+ para pasajes del satélite S3-2 sobre el hemisferio sur

Se analiza teóricamente el comportamiento del ion NO , de importancia fundamental en los mecanismos de ionización de la región F, siendo los resultados confrontados con las mediciones del satélite S3-2 en su pasaje Nº 1550 sobre la región sudamericana durante un día solar y geomagnéticamente tranquilo, el 25 de marzo de 1976. El análisis, realizado desde el punto de vista químico solamente, muestra que: i) la producción de NO+ debida a la reacción entre N+ y 02, no puede ser ignorada. ii) la teoría expuesta lleva a resultados satisfactorios debajo de los 300 km solamente, ocurriendo un apartamiento significativo, en comparación con los resultados experimentales, arriba de esa altura. iii) el desacuerdo está requiriendo términos de transporte en la ecuación de continuidad arriba de los 300 km, y, quizás, un reajuste de los coeficientes de las reacciones y el uso de modelos actualizados de atmósfera neutra.The behavior of NO+, an ion of fundamental importance on the F- region ionization mechanisms, has been theoretically analyzed, and the results confronted with the S3-2 satellite measurements on its Nº 1550 passage over the south-american region during a solar and geomagnetic quiet day, the 25 of March 1976. The analysis, carried out only from the chemical point of view, shows that i) the NO+ production due to the N+ - O2 reaction can not be ignored. ii) The expounded theory leads to satisfactory results only below 300 km, with significant departure, compared with experimenat1 results, above that altitude. iii) the disagreement is requiring transport terms in the continuity equation above 300 km, and, perhaps, a readjustment of the reactions coefficients and the usage of up to date neutral atmosphere models.Asociación Argentina de Geofísicos y Geodesta

On the origin of star-gas counterrotation in low-mass galaxies

Stars in galaxies form from the cold rotationally supported gaseous disks that settle at the center of dark matter halos. In the simplest models, such angular momentum is acquired early on at the time of collapse of the halo and preserved thereafter, implying a well-aligned spin for the stellar and gaseous component. Observations however have shown the presence of gaseous disks in counterrotation with the stars. We use the Illustris numerical simulations to study the origin of such counterrotation in low mass galaxies ($M_\star = 2 \times 10^9$ - $5 \times 10^{10}\; \rm M_\odot$), a sample where mergers have not played a significant role. Only ${\sim}1\%$ of our sample shows a counterrotating gaseous disk at $z=0$. These counterrotating disks arise in galaxies that have had a significant episode of gas removal followed by the acquisition of new gas with misaligned angular momentum. In our simulations, we identify two main channels responsible for the gas loss: a strong feedback burst and gas stripping during a fly-by passage through a more massive group environment. Once settled, counterrotation can be long-lived with several galaxies in our sample displaying misaligned components consistently for more than $2$ Gyr. As a result, no major correlation with the present day environment or structural properties might remain, except for a slight preference for early type morphologies and a lower than average gas content at a given stellar mass.Comment: 16 pages, 11 figures. Submitted to ApJ. Comments welcom

Numerical Analysis of Woltman Meter Accuracy under Flow Perturbations

[EN] One of the unknowns in the instrumentation for water measurement is what degree of influence other hydraulic elements exert on the velocity profile and, consequently, on the measurement errors. In this work, the measurement errors of a horizontal-axis Woltman meter produced by a gate valve and by a butterfly valve in different hydraulic configurations were studied using a simplified numerical model. The gate valve was installed beside the meter and three pipe diameters upstream of the meter and were operated with closures of 75%, 50% and 25%, while the butterfly valve was installed at three pipe diameters upstream of the meter with closures of 0 degrees (open) and 30 degrees. The numerical model based on the rotor's torque balance equations and Computational Fluid Dynamics (CFD) was validated by experimental tests. According to the results, it was concluded that the proposed model is valid and capable of estimating the errors caused by the hydraulic fittings arranged next to the meter. In addition, it is evident that for the analysed operating range, both valves must be installed at least three diameters of straight pipe upstream of the meter.Palau, C.; Balbastre Peralta, I.; Manzano Juarez, J.; Moreira De Azevedo, B.; Bomfim, GV. (2019). Numerical Analysis of Woltman Meter Accuracy under Flow Perturbations. Water. 11(12). https://doi.org/10.3390/w11122622111