Calculando la vejez: Gestión previsional en trabajadores/as de bajos ingresos

The Chilean pension system is a milestone regarding the institutionalization of individual responsibility and individual decisions as determinant of the pension performance. Few assessments have been made, however, to how people make decisions in this system. From a qualitative study, the following article explores how low-income workers living in Santiago make their pension decisions. Using recent perspectives in economic sociology, the article provides a dynamic interpretation of the possibilities of social agency in a complex and novel scenario, focusing on the construction of calculability frameworks that permit to make decisions and the structural and institutional elements that condition them. The last ones overflow the constructed frameworks and make necessary reframing processes through which the pension management intermingles with strategies for the generation of current incomes.El sistema de pensiones chileno constituye un hito en cuanto a la institucionalización de la responsabilidad individual y las decisiones individuales como determinante del desempeño previsional. Pocas evaluaciones se han realizado, sin embargo, a la manera como las personas toman sus decisiones en este sistema. a partir de un estudio cualitativo, el siguiente artículo explora cómo trabajadores/as de bajos ingresos de la ciudad de Santiago toman sus decisiones previsionales. Utilizando perspectivas recientes dentro de la sociología económica, el artículo ofrece una interpretación dinámica de las posibilidades de agencia en un escenario social complejo y novedoso, con foco en la construcción de marcos de calculabilidad que permiten tomar decisiones, y los elementos estructurales e institucionales que los condicionan. Estos últimos desbordan los marcos construidos y hacen necesarios procesos de re-encuadre por medio de los cuales la gestión previsional se entremezcla con estrategias para la generación de ingresos actuales

Evolution of the anti-truncated stellar profiles of S0 galaxies since z=0.6z=0.6 in the SHARDS survey: I - Sample and Methods

The controversy about the origin of the structure of S0--E/S0 galaxies may be due to the difficulty of comparing surface brightness profiles with different depths, photometric corrections and PSF effects (almost always ignored). We aim to quantify the properties of Type-III (anti-truncated) discs in a sample of S0 galaxies at 0.2<z<0.6. In this paper, we present the sample selection and describe in detail the methods to robustly trace the structure in their outskirts and correct for PSF effects. We have selected and classified a sample of 150 quiescent galaxies at 0.2<z<0.6 in the GOODS-N field. We perform a quantitative structural analysis of 44 S0-E/S0 galaxies. We corrected their surface brightness profiles for PSF distortions and analysed the biases in the structural and photometric parameters when the PSF correction is not applied. Additionally, we have developed Elbow, an automatic statistical method to determine whether a possible break is significant - or not - and its type and made it publicly available. We found 14 anti-truncated S0-E/S0 galaxies in the range 0.2<z<0.6 (~30% of the final sample). This fraction is similar to the those reported in the local Universe. In our sample, ~25% of the Type-III breaks observed in PSF-uncorrected profiles are artifacts, and their profiles turn into a Type I after PSF correction. PSF effects also soften Type-II profiles. We found that the profiles of Type-I S0 and E/S0 galaxies of our sample are compatible with the inner profiles of the Type-III, in contrast with the outer profiles. We have obtained the first robust and reliable sample of 14 anti-truncated S0--E/S0 galaxies beyond the local Universe, in the range 0.2<z<0.6. PSF effects significantly affect the shape of the surface brightness profiles in galaxy discs even in the case of the narrow PSF of HST/ACS images, so future studies on the subject should make an effort to correct them.Comment: Accepted for publishing in Astronomy & Astrophysics. 75 pages, 57 figure

Metric of a tidally perturbed spinning black hole

We explicitly construct the metric of a Kerr black hole that is tidally perturbed by the external universe in the slow-motion approximation. This approximation assumes that the external universe changes slowly relative to the rotation rate of the hole, thus allowing the parameterization of the Newman-Penrose scalar $\psi_0$ by time-dependent electric and magnetic tidal tensors. This approximation, however, does not constrain how big the spin of the background hole can be and, in principle, the perturbed metric can model rapidly spinning holes. We first generate a potential by acting with a differential operator on $\psi_0$. From this potential we arrive at the metric perturbation by use of the Chrzanowski procedure in the ingoing radiation gauge. We provide explicit analytic formulae for this metric perturbation in spherical Kerr-Schild coordinates, where the perturbation is finite at the horizon. This perturbation is parametrized by the mass and Kerr spin parameter of the background hole together with the electric and magnetic tidal tensors that describe the time evolution of the perturbation produced by the external universe. In order to take the metric accurate far away from the hole, these tidal tensors should be determined by asymptotically matching this metric to another one valid far from the hole. The tidally perturbed metric constructed here could be useful in initial data constructions to describe the metric near the horizons of a binary system of spinning holes. This perturbed metric could also be used to construct waveforms and study the absorption of mass and angular momentum by a Kerr black hole when external processes generate gravitational radiation.Comment: 17 pages, 3 figures. Final PRD version, minor typos, etc corrected. v3: corrected typo in Eq. (35) and (57

Numerical and experimental study of the fluid flow through a medical device

The purpose of this paper is to verify a commercial software based fluid–structure interaction scheme for the inferior vena cava. Vena cava deep thrombosis (TVP) is a potentially deathly disease consequent to pulmonary thromboembolism (TEP). TEP consist in the obstruction of the pulmonary artery due to a blood clot traveling in the cardiovascular system and is treated with anticoagulants and inferior vena cava filters. Flow fields along the vena cava and an antithrombus filter were studied and compared with a Particle Image Velocimetry (PIV) based model to validate the numerical model. The results show that the fluid–structure interaction (FSI) models are valid and can be used to study the deformations in the inferior vena cava wall using patient-specific geometries

Use of Trichoderma as a biocontrol agent and biofertilizer.

Species of the fungal genus Trichoderma have broad environmental opportunism, evolving from a mycoparasitic lifestyle to arivulent symbionts or even plant endophytes. Because of their ability to antagonize plant- pathogenic fungi some Trichoderma strains are used for biological control of plant diseases, acting through different mechanisms of action. Some Trichoderma strains have been registeres of commercial application as fungicide products in agriculture due the their efficacy of biocontrol, large capacity to survive in different environments, and genetic and phenotypic stability. In interaction with plants, Trichodermais able to increase plant defense responses, root development, plant growth, seed germination, leaf greennees, photosynthetic efficiency and carbon dioxide uptake, and a,eliorae abiotic stresses of facilitate a better assimilation of nutrients and detoxification of xenobiotics. Trichoderma spp. can also improve the plant nutritional level and modify the root architecture to get a more efficient nutrient uptake that can substantially increase nitrogen use efficiency in crops Some strains only express one of these mechanis,s, but the most efficient ones exhibit several of them, either simultaneously or sequentially, and can even favor the activities of rhizobacteri and mycorrhizae. Trichoderma can be ruthless with enemies but benefactor and protector of the plant in adverse situations. From a biotechnological point of view , the isolation of genes from Trichoderma spp. and this subsequent transfer to a plant genome may result in a significant improvement in plant defense and resistance to abiotic atresses

Importance of Numerical Implementation and Clustering Analysis in Force-Directed Algorithms for Accurate Community Detection

Peer reviewedPostprin

Slowly Rotating Black Holes in Dynamical Chern-Simons Gravity: Deformation Quadratic in the Spin

We derive a stationary and axisymmetric black hole solution to quadratic order in the spin angular momentum. The previously found, linear-in-spin terms modify the odd-parity sector of the metric, while the new corrections appear in the even-parity sector. These corrections modify the quadrupole moment, as well as the (coordinate-dependent) location of the event horizon and the ergoregion. Although the linear-in-spin metric is of Petrov type D, the quadratic order terms render it of type I. The metric does not possess a second-order Killing tensor or a Carter-like constant. The new metric does not possess closed timelike curves or spacetime regions that violate causality outside of the event horizon. The new, even-parity modifications to the Kerr metric decay less rapidly at spatial infinity than the leading-order in spin, odd-parity ones, and thus, the former are more important when considering black holes that are rotating moderately fast. We calculate the modifications to the Hamiltonian, binding energy and Kepler's third law. These modifications are crucial for the construction of gravitational wave templates for black hole binaries, which will enter at second post-Newtonian order, just like dissipative modifications found previously.Comment: 21 pages, 2 figures; Typos correcte

Elastic transport through dangling-bond silicon wires on H passivated Si(100)

We evaluate the electron transmission through a dangling-bond wire on Si(100)-H (2x1). Finite wires are modelled by decoupling semi-infinite Si electrodes from the dangling-bond wire with passivating H atoms. The calculations are performed using density functional theory in a non-periodic geometry along the conduction direction. We also use Wannier functions to analyze our results and to build an effective tight-binding Hamiltonian that gives us enhanced insight in the electron scattering processes. We evaluate the transmission to the different solutions that are possible for the dangling-bond wires: Jahn-Teller distorted ones, as well as antiferromagnetic and ferromagnetic ones. The discretization of the electronic structure of the wires due to their finite size leads to interesting transmission properties that are fingerprints of the wire nature

Constraining Parity Violation in Gravity with Measurements of Neutron-Star Moments of Inertia

Neutron stars are sensitive laboratories for testing general relativity, especially when considering deviations where velocities are relativistic and gravitational fields are strong. One such deviation is described by dynamical, Chern-Simons modified gravity, where the Einstein-Hilbert action is modified through the addition of the gravitational parity-violating Pontryagin density coupled to a field. This four-dimensional effective theory arises naturally both in perturbative and non-perturbative string theory, loop quantum gravity, and generic effective field theory expansions. We calculate here Chern-Simons modifications to the properties and gravitational fields of slowly spinning neutron stars. We find that the Chern-Simons correction affects only the gravitomagnetic sector of the metric to leading order, thus introducing modifications to the moment of inertia but not to the mass-radius relation. We show that an observational determination of the moment of inertia to an accuracy of 10%, as is expected from near-future observations of the double pulsar, will place a constraint on the Chern-Simons coupling constant of \xi^{1/4} < 5 km, which is at least three-orders of magnitude stronger than the previous strongest bound.Comment: 14 pages, 6 figures, replaced with version accepted for publication in Phys. Rev.