Impact of gaps in the asteroseismic characterization of pulsating stars. I. On the efficiency of pre-whitening

It is known that the observed distribution of frequencies in CoRoT and Kepler {\delta} Scuti stars has no parallelism with any theoretical model. Pre-whitening is a widespread technique in the analysis of time series with gaps from pulsating stars located in the classical instability strip such as {\delta} Scuti stars. However, some studies have pointed out that this technique might introduce biases in the results of the frequency analysis. This work aims at studying the biases that can result from pre-whitening in asteroseismology. The results will depend on the intrinsic range and distribution of frequencies of the stars. The periodic nature of the gaps in CoRoT observations, just in the range of the pulsational frequency content of the {\delta} Scuti stars, is shown to be crucial to determine their oscillation frequencies, the first step to perform asteroseismolgy of these objects. Hence, here we focus on the impact of pre-whitening on the asteroseismic characterization of {\delta} Scuti stars. We select a sample of 15 {\delta} Scuti stars observed by the CoRoT satellite, for which ultra-high quality photometric data have been obtained by its seismic channel. In order to study the impact on the asteroseismic characterization of {\delta} Scuti stars we perform the pre-whitening procedure on three datasets: gapped data, linearly interpolated data, and ARMA interpolated data. The different results obtained show that at least in some cases pre-whitening is not an efficient procedure for the deconvolution of the spectral window. therefore, in order to reduce the effect of the spectral window to the minimum it is necessary to interpolate with an algorithm that is aimed to preserve the original frequency content, and not only to perform a pre-whitening of the data.Comment: 27 pages, 47 figures Tables and typos fixe

Diagnóstico diferencial de las enfermedades prostáticas

Este trabajo incluye una revisión de los métodos de diagnóstico de las enfermedades prostáticas; además describe cómo podemos distinguir entre cada una de ellas, dependiendo del método de diagnóstico utilizado.This paper reviews the prostatic pathologies diagnosis methods; it also describes the way we can distinguish between each one depending on the one we use

Role of the electric field in surface electron dynamics above the vacuum level

Scanning tunneling spectroscopy (STS) is used to study the dynamics of hot electrons trapped on a Cu(100) surface in field emission resonances (FER) above the vacuum level. Differential conductance maps show isotropic electron interference wave patterns around defects whenever their energy lies within a surface projected band gap. Their Fourier analysis reveals a broad wave vector distribution, interpreted as due to the lateral acceleration of hot electrons in the inhomogeneous tip-induced potential. A line-shape analysis of the characteristic constant-current conductance spectra permits to establish the relation between apparent width of peaks and intrinsic line-width of FERs, as well as the identification of the different broadening mechanisms.Comment: 7 pages, 4 figures, to appear in Phys. Rev.

Fractal analysis applied to light curves of δ\delta Scuti stars

Fractal behaviour, i.e. scale invariance in spatio-temporal dynamics, have been found to describe and model many systems in nature, in particular fluid mechanics and geophysical related geometrical objects, like the convective boundary layer of cumulus cloud fields, topographic landscapes, solar granulation patterns, and observational astrophysical time series, like light curves of pulsating stars. The main interest in the study of fractal properties in such physical phenomena lies in the close relationships they have with chaotic and turbulent dynamic. In this work we introduce some statistical tools for fractal analysis of light curves: Rescaled Range Analysis (R/S), Multifractal Spectra Analysis, and Coarse Graining Spectral Analysis (CGSA), an FFT based algorithm, which can discriminate in a time series the stochastic fractal power spectra from the harmonic one. An interesting application of fractal analysis in asteroseismology concerns the joint use of all these tools in order to develop classification criteria and algorithms for {\delta}-Scuti pulsating stars. In fact from the fractal and multi-fractal fingerprints in background noise of light curves we could infer on different mechanism of stellar dynamic, among them rotation, modes excitation and magnetic activity.Comment: 13 pages, 10 figure

Mesozoic palaeogeographic evolution of the External Zones of the Betic Cordillera

14 páginas, 8 figuras.The main events characterizing the Mesozoic palaeogeographic evolution of the External Zones of the Betic Cordillera are outlined. The Triassic sediments show a 'germanic' type lacies over the entire region, ending with Late Triassic evaporites and variegated clays of Keuper facies. At the beginning of the Jurassic a transgression takes place, and a broad shallow-marine carbonate-platform environment appears. During the Carixian (180 Ma) the carbonate platform breaks down leading to the differentiation of two large palaeogeographic units: the Prebetic Zone where shallow-water environments prevailed throughout the Mesozoic, and the Subbetic Zone where the sediments are clearly pelagic. Within the Prebetic Zone, two palaeogeographic realms are differentiated: the External Prebetic ,showing important stratigraphic gaps in the Jurassic and Early Cretaceous sequence, and the Internal Prebetic with a thicker and more continuous stratigraphic sequence. Between the Prebetic and Subbetic Zones, a palaeogeographic realm is distinguished (Intermediate units) where turbiditic and pelagic materials were deposited. This zone corresponds approximately to a slope environment during most of Mesozoic times. In the Subbetic Zone a marked differential subsidence occurs during the Jurassic, leading to trough (Median Subbetic) and swells (External and Internal Subbetic). In the Median Subbetic, the deposits consist mainly of marls, pelagic limestones, radiolarites and calcareous turbidites, with mafic volcanic hand subvolcanic rocks. During the Cretaceous pelagic marls and marty limestones were laid down. Mesozoic sedimentation took place along the southern margin of the European plate, in an Atlantic-type continental margin underlain by continental crust. Three-dimensional schemes, explaining the main palaeogcographic events are included.Peer reviewe

Markov models of territory occupancy: Implications for the management and conservation of competing species

Markov chains have been frequently used in community ecology to model successional changes, but little attention has been paid to its application in population ecology as a tool to explore the outcomes of species interactions. Markov models can be regarded as >null models> that provide predicted values under a no-change scenario against which the consequences of changes in variables of interest can be assessed. Here we explore Markov chains' potential to project population trends of competing species and derive sensible management strategies. To do that we use six years of field data on territory occupancy and turn-over of two competing top predators in a Mediterranean landscape: the golden and Bonelli's eagles. The results suggest that long-term coexistence of both species in the study area is likely, with the main limitation for their coexistence being the difficulties Bonelli's eagles have in colonising new territories that become available. To avoid future declines in the population of Bonelli's eagle, it is important to take into account that the positive effects of conservation strategies focused on encouraging colonization (e.g. decreasing disperser mortality) are likely to be larger than those focused on avoiding territory abandonment (e.g. decreasing adult mortality). Markov chains are likely to be useful to evaluate the relative merit of alternative management options in other territorial species when patterns of territory occupancy are the only reliable data available, as often happens with large predators. © 2008 Springer Science+Business Media B.V.Peer Reviewe

Automated FISH spots counting in interphase nuclei

ABSTRACT NUMBER 197Work supported by grant CYCIT (TIC92-0922)