9,604 research outputs found

    A Method to Separate Stochastic and Deterministic Information from Electrocardiograms

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    In this work we present a new idea to develop a method to separate stochastic and deterministic information contained in an electrocardiogram, ECG, which may provide new sources of information with diagnostic purposes. We assume that the ECG has information corresponding to many different processes related with the cardiac activity as well as contamination from different sources related with the measurement procedure and the nature of the observed system itself. The method starts with the application of an improuved archetypal analysis to separate the mentioned stochastic and deterministic information. From the stochastic point of view we analyze Renyi entropies, and with respect to the deterministic perspective we calculate the autocorrelation function and the corresponding correlation time. We show that healthy and pathologic information may be stochastic and/or deterministic, can be identified by different measures and located in different parts of the ECG.Comment: 4 pages, 6 figure

    Primordial black hole evolution in two-fluid cosmology

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    Several processes in the early universe might lead to the formation of primordial black holes with different masses. These black holes would interact with the cosmic plasma through accretion and emission processes. Such interactions might have affected the dynamics of the universe and generated a considerable amount of entropy. In this paper we investigate the effects of the presence of primordial black holes on the evolution of the early universe. We adopt a two-fluid cosmological model with radiation and a primordial black hole gas. The latter is modelled with different initial mass functions taking into account the available constraints over the initial primordial black hole abundances. We find that certain populations with narrow initial mass functions are capable to produce significant changes in the scale factor and the entropy.Comment: 8 pages, 7 figures. Modified to match the published versio

    Probing the ZZgamma and Zgammagamma Couplings Through the Process e+e- --> nu anti-nu gamma

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    We study the sensitivity for testing the anomalous triple gauge couplings ZZγZZ\gamma and ZγγZ\gamma\gamma via the process e+e−→ννˉγe^+e^-\to \nu \bar\nu \gamma at high energy linear colliders. For integrated luminosities of 500 fb−1fb^{-1} and center of mass energies between 0.5 and 1.5 TeVTeV, we find that this process can provide tests of the triple neutral gauge boson couplings of order 10−410^{-4}, one order of magnitude lower than the standard model prediction.Comment: 12 pages, 6 figure

    The influence of massive stars in the interstellar medium of IC 1613: the supernova remnant S8 and the nebula S3 associated with a WO star

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    We present a detailed kinematical analysis of two selected nebulae in the Local Group irregular galaxy IC 1613. The nebulae are: S8, the only known supernova remnant in this galaxy, and S3, a Wolf-Rayet nebula associated with the only WO star in this galaxy. For S8, we have obtained and analyzed its radial velocity field, where we found complex profiles which can be fitted by several velocity components. These profiles also show the presence of high velocity, low density gas. From this, we have obtained the expansion velocity, estimated the preshock density and calculated the basic kinematical parameters of this SNR. We suggest that in S8 we are seing a SNR partially hidden by dust. This suggestion comes from the fact that the SNR is located between two superbubbles where a ridge of obscured material unveils the existence of dust. Moreover, we show that this hypothesis prevails when energetic arguments are taken into account. In the case of S3, this nebula shows bipolar structure. By means of its kinematics, we have analyzed its two lobes, the ``waist'', as well as its relation with the nearest superbubbles. For the first time we are able to see closed the NW lobe, showing a clover leaf shape. This fact allows a better quantitative knowledge of the nebula as a whole. Furthermore, we found evidence of an expansion motion in the NW lobe. In the light of our results, we can express that these nebulae are the product of very massive stellar evolution. It is surprising the influence these stars still have in shaping their surrounding gas, and on the energy liberation towards the interstellar medium of this galaxy.Comment: Accepted for publication in the Astronomical Journal, July issue. 11 pages, 12 figures. High resolution figures can be found at http://www.inaoep.mx/~mago/PAPERS/AJ

    Soportes epigráficos de los Orgenomescos

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    Se presenta un ensayo multidisciplinar con el que se pretende arrojar luz sobre la epigrafía cántabra, mediante la recopilación y estudio, en este caso, de las inscripciones del pueblo de los orgenomescos. El principal objetivo de este trabajo es el análisis de los soportes epigráficos utilizados por los indígenas y su evolución durante la dominación romana mediante el análisis de las 16 inscripciones conocidas, halladas en las actuales provincias de Cantabria, Asturias, Palencia y Jaén. Se distingue una sociedad indígena mixta que presenta un mestizaje entre el mundo prerromano y romano con fuertes pervivencias en sus tradiciones, resultado de un proceso de aculturación e integración onomástica y social.This multidisciplinary essay aims to shed light on the Cantabrian epigraphy, by collecting and studying, in this case, the Orgenomesci people. The main goal of this research are the epigraphic supports used by the natives and their evolution during the roman dominion, by the study of the 16 epigraphic steles and inscriptions found in the actual provinces of Cantabria, Asturias, Palencia and Jaén. Hence, we can perceive a mixted native society with miscegenation between the preroman and roman world, alongside the survival of strong traditions, consequence of an acculturization process, onomastic and social integration

    Bose-Einstein Condensate Driven by a Kicked Rotor in a Finite Box

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    We study the effect of different heating rates of a dilute Bose gas confined in a quasi-1D finite, leaky box. An optical kicked-rotor is used to transfer energy to the atoms while two repulsive optical beams are used to confine the atoms. The average energy of the atoms is localized after a large number of kicks and the system reaches a nonequilibrium steady state. A numerical simulation of the experimental data suggests that the localization is due to energetic atoms leaking over the barrier. Our data also indicates a correlation between collisions and the destruction of the Bose-Einstein condensate fraction.Comment: 7 pages, 8 figure
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