Black hole induced spins from hyperbolic encounters in dense clusters

The black holes that have been detected via gravitational waves (GW) can have either astrophysical or primordial origin. Some GW events show significant spin for one of the components and have been assumed to be astrophysical, since primordial black holes are generated with very low spins. However, it is worth studying if they can increase their spin throughout the evolution of the universe. Possible mechanisms that have already been explored are via multiple black hole mergers and gas accretion. We propose here a new mechanism that can occur in dense clusters of black holes: the spin up of primordial black holes when they are involved in close hyperbolic encounters. We explore this effect numerically with the Einstein Toolkit for different initial conditions, including variable mass ratios. For equal masses, there is a maximum spin that can be induced on the black holes, ꭕ=a/m≤0.2. We find however that for large mass ratios one can attain spins up to ꭕ≃0.7, where the highest spin is induced on the most massive black hole. For small induced spins we provide simple analytical expressions that depend on the relative velocity and impact parameterWe would like to thank Zachariah Etienne and Patrick E. Nelson for their help regarding BH hyperbolic encounters with the Einstein Toolkit. All the simulations have been run in the Hydra HPC cluster in the IFT. S.J. is supported by a predoctoral contract by the Spanish Ministry of Science, Ref. SEV-2016-0597- 19-2. The authors acknowledge support from the Research Project PGC2018-094773-B-C32 [MINECO, Spain-FEDER, Spain], and the Centro de Excelencia Severo Ochoa Program, Spain SEV-2016-059

Optimal reinforcing of reticular structures

This article presents an application of Genetic Algorithms (GA) and Finite Element Analysis (FEA) to solve a structural optimisation problem on reticular plastic structures. Structural optimisation is used to modify the original shape by placing reinforcements at optimum locations. As a result, a reduction in the maximum stress by 14,70% for a structure with a final volume increase of 8,36% was achieved. This procedure solves the structural optimisation problem by adjusting the original mold and thereby avoiding the re-construction of a new one.PACS: 02.60.PnMSC: 65-XXEste artículo presenta una aplicación de Algoritmos Genéticos (GA) y Análisis por Elementos Finitos (FEA) a la solución de un problema de optimización estructural en estructuras reticulares plásticas. Optimización estructurales usada para modificar la forma original colocando refuerzos en posiciones óptimas. Como resultado se obtuvo una reducción en el esfuerzo máximo de 14,70% para una estructura cuyo volumen original aumento en 8,36%. Este procedimiento soluciona el problema de optimización estructural ajustando el molde original y evitando la manufactura de un nuevo molde.PACS: 02.60.PnMSC: 65-X

Incidencia de la reforma del IRPF sobre la oferta laboral y el bienestar de la familia española

En este trabajo se analizan los efectos de la Reforma del Impuesto sobre la renta efectuada en España en 1999 sobre la oferta de trabajo de las unidades familiares. En primer lugar se presenta el marco fiscal de las familias antes de la reforma del IRPF de 1999 y la situación impositiva de los hogares españoles después de dicha reforma. En segundo lugar, partiendo de la estimación de una ecuación de oferta laboral de los matrimonios, en la que se tienen en cuenta los efectos cruzados de los salarios y los diferentes tipos de renta de ambos cónyuges, se estudian los efectos de la Reforma sobre el bienestar por medio del cálculo de la variación equivalente asociada a la misma. Estas estimaciones se han realizado a partir de los datos del PHOGUE 94. Los resultados permiten inferir unas ganancias de bienestar ligeramente superiores para las mujeres que para los hombres, con independencia de la situación laboral de ambos. Analizando las ganancias de bienestar por hogares, las mayores ganancias se detectan en los de rentas medias y medias altas y, para cada uno de estos grupos de renta, son mayores a medida que aumenta el número de hijos. Classification-JEL : H24, H31, J22.Impuesto sobre la renta, oferta de trabajo, variación equivalente.

The stochastic gravitational wave background from close hyperbolic encounters of primordial black holes in dense clusters

The inner part of dense clusters of primordial black holes is an active environment where multiple scattering processes take place. Some of them give rise from time to time to bounded pairs, and the rest ends up with a single scattering event. The former eventually evolves to a binary black hole (BBH) emitting periodic gravitational waves (GWs), while the latter with a short distance, called close hyperbolic encounters (CHE), emits a strong GW burst. We make the first calculation of the stochastic GW background originating from unresolved CHE sources. Unlike the case for BBH, the low-frequency tail of the SGWB from CHE is sensitive to the redshift dependence of the event rate, which could help distinguish the astrophysical from the primordial black hole contributions. We find that there is a chance that CHE can be tested by third-generation ground-based GW detectors such as Einstein Telescope and Cosmic Explorer.Comment: 7 pages, 1 figure. Changes match published versio

Circadian and Metabolic Effects of Light: Implications in Weight Homeostasis and Health

Daily interactions between the hypothalamic circadian clock at the suprachiasmatic nucleus (SCN) and peripheral circadian oscillators regulate physiology and metabolism to set temporal variations in homeostatic regulation. Phase coherence of these circadian oscillators is achieved by the entrainment of the SCN to the environmental 24-h light:dark (LD) cycle, coupled through downstream neural, neuroendocrine, and autonomic outputs. The SCN coordinate activity and feeding rhythms, thus setting the timing of food intake, energy expenditure, thermogenesis, and active and basal metabolism. In this work, we will discuss evidences exploring the impact of different photic entrainment conditions on energy metabolism. The steady-state interaction between the LD cycle and the SCN is essential for health and wellbeing, as its chronic misalignment disrupts the circadian organization at different levels. For instance, in nocturnal rodents, non-24 h protocols (i.e., LD cycles of different durations, or chronic jet-lag simulations) might generate forced desynchronization of oscillators from the behavioral to the metabolic level. Even seemingly subtle photic manipulations, as the exposure to a "dim light" scotophase, might lead to similar alterations. The daily amount of light integrated by the clock (i.e., the photophase duration) strongly regulates energy metabolism in photoperiodic species. Removing LD cycles under either constant light or darkness, which are routine protocols in chronobiology, can also affect metabolism, and the same happens with disrupted LD cycles (like shiftwork of jetlag) and artificial light at night in humans. A profound knowledge of the photic and metabolic inputs to the clock, as well as its endocrine and autonomic outputs to peripheral oscillators driving energy metabolism, will help us to understand and alleviate circadian health alterations including cardiometabolic diseases, diabetes, and obesity.Fil: Plano, Santiago Andrés. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Casiraghi, Leandro Pablo. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia Moro, Paula. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Paladino, Natalia. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Golombek, Diego Andrés. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chiesa, Juan José. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Cronobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Control of a robotic arm for transporting objects based on neuro-fuzzy learning visual information

[Abstract] New applications related to robotic manipulation or transportation tasks, with or without physical grasping are being developed. To perform these activities di erent kind of perceptions are need. One of the key perceptions in robotics is vision. However, camera-based systems have inherent errors which a ect the quality of the information obtained. Image distortion slows down information processing and defers data availability to last processing stages, decreasing performance. In this paper, a new approach to correct diverse sources of visual distortions on images in early stages of the data processing is proposed. The goal of the proposed system/algorithm is the computation of the tilt angle of an object transported by a robot. After capturing the image, the computing system extracts the angle using a Fuzzy Filter that corrects all distortions at only one processing step. This filter has been developed by means of Neuro-Fuzzy learning techniques, using data obtained from real experiments. In this way, computing time can be decreased and the performance of the robotic application can be increased. The resulting algorithm has been tried out experimentally in robot transportation tasks in the humanoid robot TEO (Task Environment Operator).Ministerio de Economía y Competitividad; DPI2013-47944-C4-1-RComunidad de Madrid; S2013/MIT-274

La red social Facebook como herramienta mediadora en los procesos de aprendizaje significativo de los estudiantes de informática de grado noveno del Colegio Deogracias Cardona

El joven del siglo XXI ha nacido en la era digital, y ya prácticamente desde que tiene conciencia manipula con facilidad cualquier dispositivo tecnológico, incluso en muchos casos estando en el vientre de su madre llega a tener una cuenta en Facebook; hoy en día nacemos para la tecnología y de la mano de esta hacemos nuestra vida. Mientras esto suceda la educación no puede seguir siendo tradicional, debe dar un paso a incorporar las herramientas tecnológicas; es aquí cuando debe entrar una mirada educomunicativa nacida desde el perfil de la licenciatura en comunicación e informática educativa y velar por generar una vinculación ante el uso de las nuevas tecnologías de la información y la comunicación en los entornos de enseñanza-aprendizaje. Es entonces como esta propuesta de Proyecto Pedagógico Mediatizado busca utilizar la red social Facebook como soporte para la aplicación de los contenidos dispuestos por el plan de área de Tecnología e Informática de grado noveno del Colegio Deogracias Cardona de Pereira y con base en la Guía 30 “Orientaciones generales para la educación en tecnología” dispuesta por el Ministerio de Educación Nacional todo esto, bajo la teoría del Psicólogo y pedagogo estadounidense David Paul Ausubel, el aprendizaje significativo

Dust reverberation mapping in distant quasars from optical and mid-infrared imaging surveys

Artículo escrito por un elevado número de autores, sólo se referencian el que aparece en primer lugar, los autores pertenecientes a la UAM y el nombre del grupo de colaboración, si lo hubiereThe size of the dust torus in active galactic nuclei (AGNs) and their high-luminosity counterparts, quasars, can be inferred from the time delay between UV/optical accretion disk continuum variability and the response in the mid-infrared (MIR) torus emission. This dust reverberation mapping (RM) technique has been successfully applied to ∼70 z ≲ 0.3 AGNs and quasars. Here we present first results of our dust RM program for distant quasars covered in the Sloan Digital Sky Survey Stripe 82 region combining ∼20 yr ground-based optical light curves with 10 yr MIR light curves from the WISE satellite. We measure a high-fidelity lag between W1 band (3.4 μm) and g band for 587 quasars over 0.3 ≲ z ≲ 2 (« z» ∼ 0.8) and two orders of magnitude in quasar luminosity. They tightly follow (intrinsic scatter ∼0.17 dex in lag) the IR lag-luminosity relation observed for z < 0.3 AGNs, revealing a remarkable size-luminosity relation for the dust torus over more than four decades in AGN luminosity, with little dependence on additional quasar properties such as Eddington ratio and variability amplitude. This study motivates further investigations in the utility of dust RM for cosmology and strongly endorses a compelling science case for the combined 10 yr Vera C. Rubin Observatory Legacy Survey of Space and Time (optical) and 5 yr Nancy Grace Roman Space Telescope 2 μm light curves in a deep survey for low-redshift AGN dust RM with much lower luminosities and shorter, measurable IR lags. The compiled optical and MIR light curves for 7384 quasars in our parent sample are made public with this wor

Sumak kawsay in Ecuador: The role of communitarian economy and the experience of the rural communities in Sarayaku (Ecuadorian Amazonia)

This paper analyzes the concrete experience of a communitarian economy (Sarayaku) from which empirical evidence may be drawn to enhance debates around development, post-development, and sumak kawsay. Some forms of land exploitation and social organization in rural communities such as this may better illustrate the communitarian economy and can provide solid and specific clarification of certain aspects of sumak kawsay. Analysis of these realities and their theoretical implications within current debates about development are the contribution of this work. In particular, the analysis of Sarayaku allows, first, to identify a non-capitalist economic rationality; second, to show some conditions of biocentrism; and, third, to verify the difficulties of translating these experiences to different territorial environments On this basis, we conclude with the difficulties of maintaining the communitarian economy, its social organization and its form of land exploitation in rural communities in the future

Improving long line stability by integrating renewables using static synchronous generators

Postprint (author's final draft