461 research outputs found

    A molecular method for the detection of sally lightfoot crab larvae (Grapsus grapsus, Brachyura, Grapsidae) in plankton samples

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    The decapod Grapsus grapsus is commonly found on oceanic islands of the Pacific and Atlantic coasts of the Americas. In this study, a simple, quick and reliable method for detecting its larvae in plankton samples is described, which makes it ideal for large-scale studies of larval dispersal patterns in the species

    Crisis teatral en Madrid durante el Trienio Liberal

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    In the spring and summer of 1820, the Madrid City Hall systematically failed to comply with the <i>Reglamento de Teatros</i> dictated by the Regency in 1812. The directors of the two troupes, Bernardo Gil and Antonio González, attempted in vain to have the constitutional laws enforced. This provoked a serious crisis made worse by the fact that the spectators also showed a preference for other more political venues. The lack of response on the part of the local authorities led the directors to cancel performances for several days in August and to publish a <i>Manifiesto</i> explaining their decision. When, for the following season, the aldermen drew up a new set of regulations which once again contravened the Regency’s <i>Regulations</i>, Bernardo Gil proposed his own <i>Proyecto de Reforma</i>, dated en April of 1821. Apart from a comprehensive proposal for theatrer reform he advances sound arguments defending the actors’ rights as citizens who make an honest living in an honorable profession.<br><br>El Ayuntamiento madrileño, en la primavera y verano de 1820, incumple sistemáticamente el <i>Reglamento de Teatros</i> aprobado por la Regencia en 1812, por lo cual los directores de las dos compañías cómicas, Bernardo Gil y Antonio González, efectuarán infructuosas gestiones a fin de que el Consistorio aplique las leyes constitucionales, lo que provoca una grave crisis teatral agudizada porque los espectadores prefieren acudir a otros recintos de carácter más político. Ante la falta de respuesta de las autoridades locales los directores suspenden las funciones durante unos días en el mes de agosto y publican un <i>Manifiesto</i> en el que justifican su postura. Para la temporada siguiente los regidores municipales elaboran una normativa que contraviene el ordenamiento teatral de la Regencia, de ahí que Bernardo Gil redacte un <i>Proyecto de Reforma</i>, fechado en abril de 1821, en el que además de una propuesta dramática integral defenderá con sólidos argumentos los derechos que tienen los cómicos como ciudadanos que ganan su sustento desempeñando una actividad honrada

    Using zeta-potential measurements to quantify peptide partition to lipid membranes

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    © The Author(s) 2011. This article is published with open access at Springerlink.com.Open Access: This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.Many cellular phenomena occur on the biomembranes. There are plenty of molecules (natural or xenobiotics) that interact directly or partially with the cell membrane. Biomolecules, such as several peptides (e.g., antimicrobial peptides) and proteins, exert their effects at the cell membrane level. This feature makes necessary investigating their interactions with lipids to clarify their mechanisms of action and side effects necessary. The determination of molecular lipid/water partition constants (Kp) is frequently used to quantify the extension of the interaction. The determination of this parameter has been achieved by using different methodologies, such as UV-Vis absorption spectrophotometry, fluorescence spectroscopy and ζ-potential measurements. In this work, we derived and tested a mathematical model to determine the Kp from ζ-potential data. The values obtained with this method were compared with those obtained by fluorescence spectroscopy, which is a regular technique used to quantify the interaction of intrinsically fluorescent peptides with selected biomembrane model systems. Two antimicrobial peptides (BP100 and pepR) were evaluated by this new method. The results obtained by this new methodology show that ζ-potential is a powerful technique to quantify peptide/lipid interactions of a wide variety of charged molecules, overcoming some of the limitations inherent to other techniques, such as the need for fluorescent labeling.This work was partially supported by project PTDC/QUI/ 69937/2006 from Fundação para a Ciência e Tecnologia-Ministério da Ciência, Tecnologia e Ensino Superior (FCT-MCTES, Portugal), and by Fundação Calouste Gulbenkian (Portugal). JMF and MMD also thank FCT-MCTES for grants IMM/BT/37-2010 and SFRH/BD/41750/2007, respectively

    Swings between rotation and accretion power in a millisecond binary pulsar

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    It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray binary, and bright X-ray emission is observed. When the rate of mass transfer decreases in the later evolutionary stages, these binaries host a radio millisecond pulsar whose emission is powered by the neutron star's rotating magnetic field. This evolutionary model is supported by the detection of millisecond X-ray pulsations from several accreting neutron stars and also by the evidence for a past accretion disc in a rotation-powered millisecond pulsar. It has been proposed that a rotation-powered pulsar may temporarily switch on during periods of low mass inflow in some such systems. Only indirect evidence for this transition has hitherto been observed. Here we report observations of accretion-powered, millisecond X-ray pulsations from a neutron star previously seen as a rotation-powered radio pulsar. Within a few days after a month-long X-ray outburst, radio pulses were again detected. This not only shows the evolutionary link between accretion and rotation-powered millisecond pulsars, but also that some systems can swing between the two states on very short timescales.Comment: 43 pages, 9 figures, 4 table. Published by Nature on 26 Sep 2013. Includes Supplementary information. Minor differences with published version may exis

    Introduction to the functional RG and applications to gauge theories

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    These lectures contain an introduction to modern renormalization group (RG) methods as well as functional RG approaches to gauge theories. In the first lecture, the functional renormalization group is introduced with a focus on the flow equation for the effective average action. The second lecture is devoted to a discussion of flow equations and symmetries in general, and flow equations and gauge symmetries in particular. The third lecture deals with the flow equation in the background formalism which is particularly convenient for analytical computations of truncated flows. The fourth lecture concentrates on the transition from microscopic to macroscopic degrees of freedom; even though this is discussed here in the language and the context of QCD, the developed formalism is much more general and will be useful also for other systems.Comment: 60 pages, 14 figures, Lectures held at the 2006 ECT* School "Renormalization Group and Effective Field Theory Approaches to Many-Body Systems", Trento, Ital

    Binary and Millisecond Pulsars at the New Millennium

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    We review the properties and applications of binary and millisecond pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1300. There are now 56 binary and millisecond pulsars in the Galactic disk and a further 47 in globular clusters. This review is concerned primarily with the results and spin-offs from these surveys which are of particular interest to the relativity community.Comment: 59 pages, 26 figures, 5 tables. Accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org
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