Infrared interferometry to spatially and spectrally resolve jets in X-ray binaries

Infrared interferometry is a new frontier for precision ground based observing, with new instrumentation achieving milliarcsecond (mas) spatial resolutions for faint sources, along with astrometry on the order of 10 microarcseconds. This technique has already led to breakthroughs in the observations of the supermassive black hole at the Galactic centre and its orbiting stars, AGN, and exo-planets, and can be employed for studying X-ray binaries (XRBs), microquasars in particular. Beyond constraining the orbital parameters of the system using the centroid wobble and spatially resolving jet discrete ejections on mas scales, we also propose a novel method to discern between the various components contributing to the infrared bands: accretion disk, jets and companion star. We demonstrate that the GRAVITY instrument on the Very Large Telescope Interferometer (VLTI) should be able to detect a centroid shift in a number of sources, opening a new avenue of exploration for the myriad of transients expected to be discovered in the coming decade of radio all-sky surveys. We also present the first proof-of-concept GRAVITY observation of a low-mass X-ray binary transient, MAXI J1820+070, to search for extended jets on mas scales. We place the tightest constraints yet via direct imaging on the size of the infrared emitting region of the compact jet in a hard state XRB.Comment: 12 Pages, 3 figures, accepted for publication in MNRA

América Latina y su gran estrategia: entre la aquiescencia y la autonomía

Este ensayo introduce el tema de la gran estrategia y su lugar y práctica en América Latina. Esta cuestión, clave en la política internacional, ha sido y es fuente de intensas e interesantes controversias conceptuales, especialmente en el mundo académico anglosajón, y un punto de referencia esencial para la elaboración de iniciativas y documentos oficiales en los países centrales. En América Latina la gran estrategia ha sido concebida y practicada en una clave singular. Se ha expresado mediante dos lógicas: la aquiescencia y la autonomía. Asimismo, en la región se han manifestado otros dos fenómenos: la existencia de «pequeñas grandes estrategias» y el surgimiento de una primera gran estrategia, en su sentido convencional, como es el caso de Brasil. Después de identificar cuatro etapas concretas en la práctica de la gran estrategia latinoamericana y de explicitar las opciones desplegadas por los países del área se llega a una conclusión de naturaleza conceptual

Macri: en busca de una nueva inserción internacional

Mauricio Macri asumió la Presidencia de Argentina el 10 de diciembre de 2015 tras ganar las elecciones en segunda vuelta por un estrecho margen de 2,68%. Una victoria que no estaba en las previsiones de casi nadie pocas semanas antes y que se construyó sobre la base de un discurso que proponía poner fin al kirchnerismo, unir a los argentinos, renovar la política y sacar al país de su “aislamiento internacional”

Magnetic screening properties of an incompressible chiral fluid

We study the possible penetration of a static magnetic field in an idealized sample of many layers supporting a two dimensional charged chiral quantum fluid, to see whether there is a kind of Meissner effect. This is a non standard problem since the quantum fluid is incompressible having a gap in its spectrum. We find that the system shows an intermediate behaviour between superconducting and non-superconducting fluids, the magnetic field being screened or not depending on its orientation relative to the layers.Comment: 20 pages, plain tex, SISSA 50/94/E

Testing Australian standard consumers' understanding of the language used to describe wine

With reference to 64 common descriptors of the sensory properties of wine (e.g., tannic, full-bodied, etc.), we investigated the extent to which these terms are understood by Australian standard consumers in relation to an opposite property (i.e., as happens in the case of experts). The study also determined how consistently these dimensions were among the group of participants. The results confirmed that the sensorial dimensions relating to wine can be modeled in terms of opposites for standard wine consumers in more than 80% of cases. However, there was a great deal of variability between the properties in terms of the opposites which were elicited indicating that some terms are less open to ambiguity while others are associated with many different opposites. A comparison of the results with those from similar studies with Italian and Vietnamese participants is addressed in the final section