Non-radial pulsations in the Be/X binaries 4U0115+63 and SAXJ2103.5+4545

The discovery of non-radial pulsations (NRP) in the Be/X binaries of the Magellanic Clouds (MC, eg. Fabrycky 2005, Coe et al. 2005, Schmidtke & Cowley 2005) provided a new approach to understand these complex systems, and, at the same time, favoured the synergy between two different fields: stellar pulsations and X-ray binaries. This breakthrough was possible thanks to the MACHO and OGLE surveys. However, in our Galaxy, only two Be/X have been reported to show NRP: GROJ2058+42 (Kiziloglu et al. 2007) and LSI+61 235 (Sarty et al. 2009). Our objective is to study the short-term variability of Galactic Be/X binaries, compare them to the Be/X of the MC and to the isolated Galactic Be observed with CoRoT and Kepler. We present preliminary results of two Be/X stars, namely 4U0115+63 and SAXJ2103.5+4545 showing multiperiodicity and periodicity respectively, most probably produced by non-radial pulsations.Comment: 2 pages, 2 figures, IAUS 272 "Active OB stars: structure, evolution, mass loss and critical limits" conference, Paris, July 2010, submitte

Oil Shocks and Monetary Policy in an Estimated DSGE Model for a Small Open Economy

This paper analyzes the effects of oil-price shocks from a general equilibrium standpoint. We develop a dynamic stochastic general equilibrium (DSGE) model, estimated by Bayesian methods for the Chilean economy. The model explicitly includes oil in the consumption basket and also in the technology used by domestic firms. With the estimated model we simulate how monetary policy and other variables would respond to an oil-price shock under the policy rule that best describes the behavior of the Central Bank of Chile (CBC). We also simulate the counterfactual responses in a flexible prices and wages equilibrium, and under alternative monetary frameworks. We show that a 13% increase in the real price of oil leads to a fall in output of about 0.5% and an increase in inflation of about 0.4%. The contractionary effect of the oil shock is mainly due to the endogenous tightening of the monetary policy.

The Chilean Business Cycles Through the Lens of a Stochastic General Equilibrium Model

This paper uses an estimated dynamic stochastic general equilibrium model with nominal and real rigidities, to describe the sources of business cycle fluctuations in Chile. Our results show that foreign shocks and domestic supply shock account for a large share of output fluctuations over the last 20 years. Relatively tight domestic monetary conditions have contributed to contain inflationary pressures arising from other shocks, namely a slowdown in productivity by mid 90s. Foreign factors are also behind the large swings exhibited by the real exchange rate, although a monetary contraction in 1998 explains part of the delayed adjustment of the exchange rate in response to effects of the Asian crisis. The tight monetary policy around 1998 also contributes to the slow recovery of the employment afterwards.

Invisibility and PT Symmetry: A Simple Geometrical Viewpoint

We give a simplified account of the properties of the transfer matrix for a complex one-dimensional potential, paying special attention to the particular instance of unidirectional invisibility. In appropriate variables, invisible potentials appear as performing null rotations, which lead to the helicity-gauge symmetry of massless particles. In hyperbolic geometry, this can be interpreted, via M\"{o}bius transformations, as parallel displacements, a geometric action that has no Euclidean analogy.Comment: 13 pages. No figure. Accepted for publication in Symmetr

Psicología social ¿para qué?

Doing research involves a minimum set of responsibilities. One of the is to ask why do research? Today researches and students do not ask about it. They assume they have to do research as mandatory. Research becomes a means and not and end. This paper is an overview of social psychology in Mexico (some statistical data is provided). It shows three aspects of how social psychology is addressed and some critical reflections that could be useful for those engaged in research in social psychology.Hacer investigación implica un conjunto de responsabilidades mínimas. Una de ellas es preguntarse ¿para qué hacer investigación? En el mundo actual los investigadores y los estudiantes no suelen preguntárselo. Suponen que deben hacer investigación como una obligación. Esto hace que la investigación se convierta en un medio y no en un fin. En este texto se brinda un panorama general de la psicología social en México recurriendo a algunos datos estadísticos. Posteriormente se abordan tres aspectos de la forma en que se hace psicología social y se ofrecen algunas reflexiones críticas que podrían ser útiles para quienes se dedican a la investigación en psicología social

Psicología Social

Las historias románticamente grandes cuentan con tres elementos: dragón, princesa y caballero, que vistos de otra forma son la maldad, la bondad y la valentía, en conjunto, como unidad, no como elementos aislados. Al romance no se le podría encontrar nunca en el lloriqueo de la princesa que ha sido aislada en una torre del castillo o robada por el dragón. Tampoco puede encontrársele en la desesperación del caballero que agiganta el paso con la única finalidad de rescatar a su doncella

Prehistoric psychotropic consumption in Andean Chilean mummies

Hallucinogenic plants are often regarded as the main source of psychoactive drugs in antiquity to reach deep altered states of consciousness^1,2^. Many researchers believe this was particularly true during the Tiwanaku empire expansion, circa (500-1000 A.D.), along the Atacama Desert of Chile. Highly decorated snuffing tablets and tubes are often found as grave goods during this period^3,4,5,6,7,8^. Until now the type of drugs consumed in this paraphernalia has been unclear. From the modern city of Arica, naturally mummified human bodies with abundant hair provided a unique opportunity to test for hallucinogenic plants consumed in Andean prehistory. Analysis by gas chromatography and mass spectrometry demonstrated the presence of harmine. The Banisteriopsis vine, commonly called Ayahuasca, was the probable source. This is the first confirmed evidence of psychoactive plant consumption in pre-Hispanic Andean populations along the Atacama coastal region. Of the 32 mummy hair samples analyzed 3 males tested positive for harmine. This alkaloid aids in the catalysis and synergic effects of powerful hallucinogenic drugs. The consumption of harmine was likely related to medicinal practices and not exclusively ingested by shamans. Another important aspect of this evidence is that Banisteriopsis is an Amazon plant. It does not grow in the Atacama coastal region. Thus, our findings reveal extensive plant trade networks in antiquity between the coast, desert, highlands, and Amazon basin. The excellent preservation of human organic specimens, the use of gas chromatography and mass spectrometry allowed us to map and demonstrate the consumption of psychoactive compound plants in Andean prehistory. In addition, our findings open the door for future studies to debate the consumption and social role of ancient psychoactive and hallucinogenic plants

What Drives the Current Account in Commodity Exporting Countries? The Cases of Chile and New Zealand

This paper uses an open economy DSGE model with a commodity sector and nominal and real rigidities to ask what factors account for current account developments in two small commodity exporting countries. We estimate the model, using Bayesian techniques, on Chilean and on New Zealand data, and investigate the structural factors that explain the behaviour of the two countries’ current accounts. We find that foreign financial conditions, investment-specific shocks, and foreign demand shocks account for the bulk of the variation of the current accounts of the two countries. In the case of New Zealand, fluctuations in commodity export prices have also been important. Counterfactual experiments indicate that (i) a peso denomination of the Chilean external debt would reduce the impact of external shocks on the exchange rate and domestic variables, and the influence of monetary policy on the current account; and (ii) more or less aggressive monetary policy in New Zealand offers little scope for stabilizing the exchange rate and the current account.

Aportación al estudio sobre la fenología reproductora de las algas pardas y verdes del litoral del Sureste de España

We provide information about the reproductive phenology of 30 taxa of brown algae and 20 of green ones in the South-East of Spain, comparing the phenologic behaviour observed with the one already described in adjoining areas of the Spanish Mediterranean. We also interpreted the reproductive phenology according to the observations made on the coast and the consulted bibliography.En este trabajo se aporta información sobre la fenología reproductura de 30 tiixones de algas pardas y 20 de algas verdes en el Sureste de España, comparando el comportamiento fenolágico observado con el descrito en áreas adyacentes del mediterráneo español. Paralelamente, se interpreta la fenología detectada en base a las observaciones realizadas en el litoral y a la bibliografía consultada