FILOU oscillation code

The present paper provides a description of the oscillation code FILOU, its main features, type of applications it can be used for, and some representative solutions. The code is actively involved in CoRoT/ESTA exercises (this volume) for the preparation for the proper interpretation of space data from the CoRoT mission. Although CoRoT/ESTA exercises have been limited to the oscillations computations for non-rotating models, the main characteristic of FILOU is, however, the computation of radial and non-radial oscillation frequencies in presence of rotation. In particular, FILOU calculates (in a perturbative approach) adiabatic oscillation frequencies corrected for the effects of rotation (up to the second order in the rotation rate) including near degeneracy effects. Furthermore, FILOU works with either a uniform rotation or a radial differential rotation profile (shellular rotation), feature which makes the code singular in the field.Comment: 6 pages, 5 figures. Astrophysics and Space Science (in press

The role of rotation on Petersen Diagrams. II The influence of near-degeneracy

In the present work, the effect of near-degeneracy on rotational Petersen diagrams (RPD) is analysed. Seismic models are computed considering rotation effects on both equilibrium models and adiabatic oscillation frequencies (including second-order near-degeneracy effects). Contamination of coupled modes and coupling strength on the first radial modes are studied in detail. Analysis of relative intrinsic amplitudes of near-degenerate modes reveals that the identity of the fundamental radial mode and its coupled quadrupole pair are almost unaltered once near-degeneracy effects are considered. However, for the first overtone, a mixed radial/quadrupole identity is always predicted. The effect of near-degeneracy on the oscillation frequencies becomes critical for rotational velocities larger than 15-20 km/s, for which large wriggles in the evolution of the period ratios are obtained (up $10^{-2}$). Such wriggles imply uncertainties, in terms of metallicity determinations using RPD, reaching up to 0.50 dex, which can be critical for Pop. I HADS (High Amplitude \dss). In terms of mass determinations, uncertainties reaching up to 0.5 M_sun are predicted. The location of such wriggles is found to be independent of metallicity and rotational velocity, and governed mainly by the avoided-crossing phenomenon.Comment: 8 pages, 7 figures, 1 table. (accepted for publication in A&A

Non-equilibrium transport response from equilibrium transport theory

We propose a simple scheme that describes accurately essential non-equilibrium effects in nanoscale electronics devices using equilibrium transport theory. The scheme, which is based on the alignment and dealignment of the junction molecular orbitals with the shifted Fermi levels of the electrodes, simplifies drastically the calculation of current-voltage characteristics compared to typical non-equilibrium algorithms. We probe that the scheme captures a number of non-trivial transport phenomena such as the negative differential resistance and rectification effects. It applies to those atomic-scale junctions whose relevant states for transport are spatially placed on the contact atoms or near the electrodes.Comment: 5 pages, 4 figures. Accepted in Physical Review

Inconsistencies in the application of harmonic analysis to pulsating stars

Using ultra-precise data from space instrumentation we found that the underlying functions of stellar light curves from some AF pul- sating stars are non-analytic, and consequently their Fourier expansion is not guaranteed. This result demonstrates that periodograms do not provide a mathematically consistent estimator of the frequency content for this kind of variable stars. More importantly, this constitutes the first counterexample against the current paradigm which considers that any physical process is described by a contin- uous (band-limited) function that is infinitely differentiable.Comment: 9 pages, 8 figure

Female labour supply in Spain: The importance of behavioural assumptions and unobserved heterogeneity specification

We estimate four models of female labour supply using a Spanish sample of married women from 1994, taking into account the complete form of the individual’s budget set. The models differ in the hypotheses relating to the presence of optimisation errors and/or the way non-workers contribute to the likelihood function. According to the results, the effects of wages and non-labour income on the labour supply of Spanish married women depend on the specification used. The model which has both preference and optimisation errors and allows for both voluntarily and involuntarily unemployed females desiring to participate seems to better fit the evidence for Spanish married women.Labour supply, taxes, unobserved heterogeneity

New detections of H2O masers in planetary nebulae and post-AGB stars using the Robledo-70m antenna

Aims: We investigated the possible relationship between the evolutionary stage of post-AGB stars and planetary nebulae (PNe) and the presence of water masers in their envelopes. Methods: We have used NASA's 70-m antenna in Robledo de Chavela (Spain) to search for the water maser transition at 22235.08 MHz, towards a sample of 105 sources with IRAS colour characteristic of post-AGB stars and PNe at declination >-32 deg. 83% of the sources in the sample are post-AGB stars, 15% PNe or PN candidates, while only 2% seem to be HII regions. Results: We have detected five water masers, of which four are reported for the first time: two in PNe (IRAS 17443-2949 and IRAS 18061-2505), a ``water fountain'' in a post-AGB star (IRAS 16552-3050), and one in a source previously catalogued as a PN, but whose classification is uncertain (IRAS 17580-3111). Conclusions: The unexpected detections of water masers in two objects among the small subset of PNe led us to suggest that the PNe harbouring water masers are a special type of massive, rapidly evolving PNe.Comment: 15 pages, 7 figures. Accepted for publication in Astronomy and Astrophysic