Triggering magnetar outbursts in 3D force-free simulations

In this letter, we present the first 3D force-free general relativity simulations of the magnetosphere dynamics related to the magnetar outburst/flare phenomenology. Starting from an initial dipole configuration, we adiabatically increase the helicity by twisting the footprints of a spot on the stellar surface and follow the succession of quasi-equilibrium states until a critical twist is reached. Twisting beyond that point triggers instabilities that results in the rapid expansion of magnetic field lines, followed by reconnection, as observed in previous axi-symmetric simulations. If the injection of magnetic helicity goes on, the process is recurrent, periodically releasing a similar amount of energy, of the order of a few % of the total magnetic energy. From our current distribution, we estimate the local temperature assuming that dissipation occurs mainly in the highly resistive outermost layer of the neutron star. We find that the temperature smoothly increases with injected twist, being larger for spots located in the tropical regions than in polar regions, and rather independent of their sizes. After the injection of helicity ceases, the magnetosphere relaxes to a new stable state, in which the persistent currents maintain the footprints area slightly hotter than before the onset of the instability.Comment: 6 pages, 5 figure

Claves bíblicas del Documento de Aparecida

El Documento de Aparecida ha tenido el tiempo suficiente para adentrarse en el corazón de los creyentes. Es hora de evaluar sus desafíos pastorales. En este artículo trataremos de analizar los principales elementos bíblicos que iluminan esta hoja de ruta de la Iglesia latinoamericana y caribeña en el próximo decenio

Unobserved Heterogeneity and Intertemporal Nonseparability: Evidence from Consumption Panel Data

In this paper we analyze the importance of intertemporal non-separabilities for consumption decisions using household data. We follow the test suggested by Meghir and Weber (1996), so we exploit the variability of the within-period marginal rate of substitution (MRS) between commodities. We also check for the presence of liquidity constraints by comparing the results obtained from theMRS to those of the Euler equations. For that purpose, we use a Spanish data set in which households are observed up to eight consecutive quarters. This length of the temporal dimension is crucial, since it allows both to account for the dynamics of consumption in the preferences as well as to control for time invariant unobserved heterogeneity across households. Our results confirm the importance of accounting for fixed effects when analyzing intertemporal consumption decisions allowing for time non-separabilities. Once we control for fixed effects and use the adequate set of instruments we do not find evidence of misspecification and the results yield supporting evidence of habit formation.Consumption, panel data, unobserved heterogeneity, habits, durability

Clustering Learning for Robotic Vision

We present the clustering learning technique applied to multi-layer feedforward deep neural networks. We show that this unsupervised learning technique can compute network filters with only a few minutes and a much reduced set of parameters. The goal of this paper is to promote the technique for general-purpose robotic vision systems. We report its use in static image datasets and object tracking datasets. We show that networks trained with clustering learning can outperform large networks trained for many hours on complex datasets.Comment: Code for this paper is available here: https://github.com/culurciello/CL_paper1_cod

Emerging jet probes of strongly interacting dark sectors

A strongly interacting dark sector can give rise to a class of signatures dubbed dark showers, where in analogy to the strong sector in the Standard Model, the dark sector undergoes its own showering and hadronization, before decaying into Standard Model final states. When the typical decay lengths of the dark sector mesons are larger than a few centimeters (and no larger than a few meters) they give rise to the striking signature of emerging jets, characterized by a large multiplicity of displaced vertices. In this article we consider the general reinterpretation of the CMS search for emerging jets plus prompt jets into arbitrary new physics scenarios giving rise to emerging jets. More concretely, we consider the cases where the SM Higgs mediates between the dark sector and the SM, for several benchmark decay scenarios. Our procedure is validated employing the same model than the CMS emerging jet search. We find that emerging jets can be the leading probe in regions of parameter space, in particular when considering the so-called \emph{gluon portal} and \emph{dark photon portal} decay benchmarks. With the current 16.1 fb$^{-1}$ of luminosity this search can exclude down to ${\cal O} (20) \%$ exotic branching ratio of the SM Higgs, but a naive extrapolation to the 139 fb$^{-1}$ luminosity employed in the current model-independent, indirect bound of 16 \% would probe exotic branching ratios into dark quarks down to below 10 \%. Further extrapolating these results to the HL-LHC, we find that one can pin down exotic branching ratio values of 1\%, which is below the HL-LHC expectations of 2.5$-$4 \%. We make our recasting code publicly available, as part of the LLP Recasting Repository

Analysis of structures subjected to dynamic loading.

The objective of this thesis is to develop computer programs for the dynamic analysis of structures. For a shear building two computer programs were developed: (1) Dynamic Analysis of a Shear Building within the Elastic Range and (2) the Dynamic Analysis of a Shear Building with Elasto-Plastic Behavior. Parallel to this computer work a study was performed to investigate the error due to static condensation applied to dynamic problems. In the development of computer programs the stiffness method and the consistent mass matrix were used; and viscous damping was assumed

Unified Management of Applications on Heterogeneous Clouds

La diversidad con la que los proveedores cloud ofrecen sus servicios, definiendo sus propias interfaces y acuerdos de calidad y de uso, dificulta la portabilidad y la interoperabilidad entre proveedores, lo que incurre en el problema conocido como el bloqueo del vendedor. Dada la heterogeneidad que existe entre los distintos niveles de abstracción del cloud, como IaaS y PaaS, hace que desarrollar aplicaciones agnósticas que sean independientes de los proveedores y los servicios en los que se van a desplegar sea aún un desafío. Esto también limita la posibilidad de migrar los componentes de aplicaciones cloud en ejecución a nuevos proveedores. Esta falta de homogeneidad también dificulta el desarrollo de procesos para operar las aplicaciones que sean robustos ante los errores que pueden ocurrir en los distintos proveedores y niveles de abstracción. Como resultado, las aplicaciones pueden quedar ligadas a los proveedores para las que fueron diseñadas, limitando la capacidad de los desarrolladores para reaccionar ante cambios en los proveedores o en las propias aplicaciones. En esta tesis se define trans-cloud como una nueva dimensión que unifica la gestión de distintos proveedores y niveles de servicios, IaaS y PaaS, bajo una misma API y hace uso del estándar TOSCA para describir aplicaciones agnósticas y portables, teniendo procesos automatizados, por ejemplo para el despliegue. Por otro lado, haciendo uso de las topologías estructuradas de TOSCA, trans-cloud propone un algoritmo genérico para la migración de componentes de aplicaciones en ejecución. Además, trans-cloud unifica la gestión de los errores, permitiendo tener procesos robustos y agnósticos para gestionar el ciclo de vida de las aplicaciones, independientemente de los proveedores y niveles de servicio donde se estén ejecutando. Por último, se presentan los casos de uso y los resultados de los experimentos usados para validar cada una de estas propuestas