An intrinsic Proper Generalized Decomposition for parametric symmetric elliptic problems

We introduce in this paper a technique for the reduced order approximation of parametric symmetric elliptic partial differential equations. For any given dimension, we prove the existence of an optimal subspace of at most that dimension which realizes the best approximation in mean of the error with respect to the parameter in the quadratic norm associated to the elliptic operator, between the exact solution and the Galerkin solution calculated on the subspace. This is analogous to the best approximation property of the Proper Orthogonal Decomposition (POD) subspaces, excepting that in our case the norm is parameter-depending, and then the POD optimal sub-spaces cannot be characterized by means of a spectral problem. We apply a deflation technique to build a series of approximating solutions on finite-dimensional optimal subspaces, directly in the on-line step. We prove that the partial sums converge to the continuous solutions, in mean quadratic elliptic norm.Comment: 18 page

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

European rabbit restocking: a critical review in accordance with IUCN (1998) guidelines for re–introduction

Repoblaciones de conejo europeo: una revisión crítica según las directrices de la IUCN (1998) para las reintroducciones Las repoblaciones de conejo europeo son una de las medidas más empleadas en los cotos de caza y en los proyectos de conservación en España, Francia y Portugal, donde el conejo es una especie clave. El objetivo de este trabajo consiste en revisar el conocimiento actual sobre los factores que afectan al establecimiento de las poblaciones de conejo reintroducidas según las directrices de la IUCN (1998), a fin de determinar las lagunas de conocimiento en este ámbito y destacar las técnicas que mejoran los buenos resultados reales de las reintroducciones. Ocho de los 17 puntos seleccionados de estas directrices se identificaron como desconocidos o parcialmente estudiados, incluidos importantes aspectos como el manejo y la liberación de conejos salvajes criados en cautividad, la elaboración de planes de transporte y seguimiento, la aplicación de programas de vacunación y los estudios a largo plazo posteriores a la liberación. Por lo tanto, los investigadores deben concentrar sus esfuerzos en suprimir esta falta de conocimiento y los gestores deben analizar todos los factores que aquí revisamos, con el objetivo de establecer unas directrices precisas para las futuras repoblaciones de conejo.Repoblaciones de conejo europeo: una revisión crítica según las directrices de la IUCN (1998) para las reintroducciones Las repoblaciones de conejo europeo son una de las medidas más empleadas en los cotos de caza y en los proyectos de conservación en España, Francia y Portugal, donde el conejo es una especie clave. El objetivo de este trabajo consiste en revisar el conocimiento actual sobre los factores que afectan al establecimiento de las poblaciones de conejo reintroducidas según las directrices de la IUCN (1998), a fin de determinar las lagunas de conocimiento en este ámbito y destacar las técnicas que mejoran los buenos resultados reales de las reintroducciones. Ocho de los 17 puntos seleccionados de estas directrices se identificaron como desconocidos o parcialmente estudiados, incluidos importantes aspectos como el manejo y la liberación de conejos salvajes criados en cautividad, la elaboración de planes de transporte y seguimiento, la aplicación de programas de vacunación y los estudios a largo plazo posteriores a la liberación. Por lo tanto, los investigadores deben concentrar sus esfuerzos en suprimir esta falta de conocimiento y los gestores deben analizar todos los factores que aquí revisamos, con el objetivo de establecer unas directrices precisas para las futuras repoblaciones de conejo.European rabbit restocking is one of the most frequent actions in hunting estates and conservation projects in Spain, France and Portugal where rabbit is a keystone species. The aim of this work was to review current knowledge regarding rabbit restocking in accordance with the IUCN (1998) guidelines for re–introduction in order to identify gaps in knowledge and highlight the techniques that improve the overall success rate. Eight of 17 items selected from these guidelines were identified as partly studied or unknown, including important items such as the management and release of captive–reared wild rabbits, the development of transport and monitoring programs, the application of vaccine programs, and post–release long–term studies. Researchers should therefore concentrate their efforts on bridging these knowledge gaps, and wildlife managers should consider all the factors reviewed herein so as to establish accurate management guidelines for subsequent rabbit restocking programs

Vacuum fluctuations and the conditional homodyne detection of squeezed light

Conditional homodyne detection of quadrature squeezing is compared with standard nonconditional detection. Whereas the latter identifies nonclassicality in a quantitative way, as a reduction of the noise power below the shot noise level, conditional detection makes a qualitative distinction between vacuum state squeezing and squeezed classical noise. Implications of this comparison for the realistic interpretation of vacuum fluctuations (stochastic electrodynamics) are discussed.Comment: 14 pages, 7 figures, to appear in J. Opt. B: Quantum Semiclass. Op

Phase-dependent exciton transport and energy harvesting from thermal environments

Non-Markovian effects in the evolution of open quantum systems have recently attracted widespread interest, particularly in the context of assessing the efficiency of energy and charge transfer in nanoscale biomolecular networks and quantum technologies. With the aid of many-body simulation methods, we uncover and analyse an ultrafast environmental process that causes energy relaxation in the reduced system to depend explicitly on the phase relation of the initial state preparation. Remarkably, for particular phases and system parameters, the net energy flow is uphill, transiently violating the principle of detailed balance, and implying that energy is spontaneously taken up from the environment. A theoretical analysis reveals that non-secular contributions, significant only within the environmental correlation time, underlie this effect. This suggests that environmental energy harvesting will be observable across a wide range of coupled quantum systems.Comment: 5 + 4 pages, 3 + 2 figures. Comments welcom

Phosphoproteomics data classify hematological cancer cell lines according to tumor type and sensitivity to kinase inhibitors

This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Homogenization of the one-dimensional wave equation

We present a method for two-scale model derivation of the periodic homogenization of the one-dimensional wave equation in a bounded domain. It allows for analyzing the oscillations occurring on both microscopic and macroscopic scales. The novelty reported here is on the asymptotic behavior of high frequency waves and especially on the boundary conditions of the homogenized equation. Numerical simulations are reported

A study on disability glare vision in young adult subjects

The full assessment of the visual system must include the evaluation of the optical quality of the eye and neural visual functions. The objective evaluation of the retinal image quality is often carried out by computing the point spread function (PSF) of the eye. The central part of the PSF is associated with optical aberrations and the peripheral areas with scattering contributions. In that sense, visual acuity and contrast sensitivity function tests can be considered the perceptual neural response to those contributions characterizing the eye’s PSF. However, in natural viewing conditions, visual acuity tests may provide good vision while contrast sensitivity tests can reveal visual impairment in glare vision conditions, such as exposure to bright light sources or night driving conditions. Here we present an optical instrument for the study of disability glare vision under extended Maxwellian illumination to assess the contrast sensitivity function under glare conditions. The limit of the Total Disability Glare threshold, tolerance, and glare adaptation will be investigated as a function of the angular size of the glare source (GA) and the contrast sensitivity function in young adult subjects