Studying the interaction between microquasar jets and their environments

In high-mass microquasars (HMMQ), strong interactions between jets and stellar winds at binary system scales could occur. In order to explore this possibility, we have performed numerical 2-dimensional simulations of jets crossing the dense stellar material to study how the jet will be affected by these interactions. We find that the jet head generates strong shocks in the wind. These shocks reduce the jet advance speed, and compress and heat up jet and wind material. In addition, strong recollimation shocks can occur where pressure balance between the jet side and the surrounding medium is reached. All this, altogether with jet bending, could lead to the destruction of jets with power $<10^{36} \rm{erg/s}$. The conditions around the outflow shocks would be convenient for accelerating particles up to $\sim$TeV energies. These accelerated particles could emit via synchrotron and inverse Compton (IC) scattering if they were leptons, and via hadronic processes in case they were hadrons.Comment: 4 pages. Contribution to the proceedings of High Energy Phenomena in Relativistic Outflows, held in Dublin, Ireland, September 24-28, 200

Clock spectroscopy of interacting bosons in deep optical lattices

We report on high-resolution optical spectroscopy of interacting bosonic $^{174}$Yb atoms in deep optical lattices with negligible tunneling. We prepare Mott insulator phases with singly- and doubly-occupied isolated sites and probe the atoms using an ultra-narrow "clock" transition. Atoms in singly-occupied sites undergo long-lived Rabi oscillations. Atoms in doubly-occupied sites are strongly affected by interatomic interactions, and we measure their inelastic decay rates and energy shifts. We deduce from these measurements all relevant collisional parameters involving both clock states, in particular the intra- and inter-state scattering lengths

Fast solution of Cahn-Hilliard variational inequalities using implicit time discretization and finite elements

We consider the e�cient solution of the Cahn-Hilliard variational inequality using an implicit time discretization, which is formulated as an optimal control problem with pointwise constraints on the control. By applying a semi-smooth Newton method combined with a Moreau-Yosida regularization technique for handling the control constraints we show superlinear convergence in function space. At the heart of this method lies the solution of large and sparse linear systems for which we propose the use of preconditioned Krylov subspace solvers using an e�ective Schur complement approximation. Numerical results illustrate the competitiveness of this approach

On the interaction of jets with stellar winds in XRBs

We present the first three-dimensional simulations of the evolution of a microquasar jet inside the binary-star system. The aim is to study the interaction of these jets with the stellar wind from a massive companion and the possible locations of high-energy emission sites. We have simulated two jets with different injection power in order to give a hint on the minimum power required for the jet to escape the system and become visible in larger scales. In the setup, we include a massive star wind filling the grid through which the jet evolves. We show that jets should have powers of the order of $10^{37}\rm{erg/s}$ or more in order not to be destroyed by the stellar wind. The jet-wind interaction results in regions in which high energy emission could be produced. These results imply the possible existence of a population of X-ray binaries not detected in the radio band due to jet disruption inside the region dominated by the stellar wind.Comment: Published in Proceedings of High Energy Phenomena in Relativistic Outflows II, held in Buenos Aires, 26-30 October 2009, ed. G. Romer

Person to Person in Norway

While still in the midst of their study abroad experiences, students at Linfield College write reflective essays. Their essays address issues of cultural similarity and difference, compare lifestyles, mores, norms, and habits between their host countries and home, and examine changes in perceptions about their host countries and the United States. In this essay, Amber Hay describes her observations during her study abroad program at Telemark University College in Bø, Norway

The development of power specific redlines for SSME safety monitoring

Over the past several years, there has been an increased awareness in the necessity for rocket engine health monitoring because of the cost and complexity of present and future systems. A current rocket engine system, the Space Shuttle Main Engine (SSME), combines a limited redline system with closed-loop control of the engine's thrust level and mixture ratio. Despite these features, 27 tests of the SSME have resulted in major incidents. A SSME transient model was used to examine the effect of variations in high pressure turbopump performance on various engine parameters. Based on analysis of the responses, several new parameters are proposed for further investigation as power-level specific redlines

Compatibility and stability of hyoscine n-butyl bromide and furosemide admixtures for use in palliative care

In order to avoid separate injections, admixtures of drugs are frequently used in palliative care settings. There are different factors that can influence the compatibility and stability of the mixture: drug type, concentration, solvent, container, temperature and light. There are some mixtures of drugs with proven stability, but there is lack of evidence about the stability and compatibility of the combination of hyoscine N-butyl bromide and furosemide.Universidad de Málaga,Campus de Excelencia Internacional Andalucía Tec

The trade-offs of social assistance programs in the labor market: The case of the “Seguro Popular” program in Mexico

In 2002, the Mexican government began a tremendous financial effort to provide health insurance, Seguro Popular (SP), to the 50 million uninsured in Mexico. In doing so, the states and municipalities offered virtually free health insurance to uncovered self-employed and informal salaried workers substantially altering the incentives for workers and firms to operate in the formal economy. We take advantage of the staggered implementation of the program across municipalities to estimate the effects of the SP in the labor market. We find that the SP had a negative effect in the creation of formal jobs, especially in small and medium sized firms. According to our estimates, had the program not been in place, 31.000 more employers and 300.000 new formal jobs should have been registered with Mexican social security. These represent 3.8% and 2.4% of the stock of registered employers and employees in 2002 when the program started.social assistance program, informality, labor market, Mexico

Super-Resolution for Overhead Imagery Using DenseNets and Adversarial Learning

Recent advances in Generative Adversarial Learning allow for new modalities of image super-resolution by learning low to high resolution mappings. In this paper we present our work using Generative Adversarial Networks (GANs) with applications to overhead and satellite imagery. We have experimented with several state-of-the-art architectures. We propose a GAN-based architecture using densely connected convolutional neural networks (DenseNets) to be able to super-resolve overhead imagery with a factor of up to 8x. We have also investigated resolution limits of these networks. We report results on several publicly available datasets, including SpaceNet data and IARPA Multi-View Stereo Challenge, and compare performance with other state-of-the-art architectures.Comment: 9 pages, 9 figures, WACV 2018 submissio

Leptonic emission from microquasar jets: from radio to very high-energy gamma-rays

Microquasars are sources of very high-energy gamma-rays and, very probably, high-energy gamma-ray emitters. We propose a model for a jet that can allow to give accurate observational predictions for jet emission at different energies and provide with physical information of the object using multiwavelength data.Comment: 2 pages, 1 figure. Proceedings of the conference: "International Astronomical Union Symposium No. 230: Populations of High Energy Sources in Galaxies". Edited by Evert J.A. Meurs & Giuseppina Fabbian