461 research outputs found
A molecular method for the detection of sally lightfoot crab larvae (Grapsus grapsus, Brachyura, Grapsidae) in plankton samples
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
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 compañĂas cĂłmicas, 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 polĂtico. Ante la falta de respuesta de las autoridades locales los directores suspenden las funciones durante unos dĂas 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 ahĂ 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 sĂłlidos argumentos los derechos que tienen los cĂłmicos como ciudadanos que ganan su sustento desempeñando una actividad honrada
Using zeta-potential measurements to quantify peptide partition to lipid membranes
© 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
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
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
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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