221 research outputs found
The influence of the Lande -factor in the classical general relativistic description of atomic and subatomic systems
We study the electromagnetic and gravitational fields of the proton and
electron in terms of the Einstenian gravity via the introduction of an
arbitrary Lande -factor in the Kerr-Newman solution. We show that at length
scales of the order of the reduced Compton wavelength, corrections from
different values of the -factor are not negligible and discuss the presence
of general relativistic effects in highly ionized heavy atoms. On the other
hand, since at the Compton-wavelength scale the gravitational field becomes
spin dominated rather than mass dominated, we also point out the necessity of
including angular momentum as a source of corrections to Newtonian gravity in
the quantum description of gravity at this scale.Comment: 11 pages, 2 figure
Genomic Evolution of Two Acinetobacter baumannii Clinical Strains from ST-2 Clones Isolated in 2000 and 2010 (ST-2_clon_2000 and ST-2_clon_2010)
Acinetobacter baumannii is a successful nosocomial pathogen due to its ability to persist in hospital environments by acquiring
mobile elements such as transposons, plasmids, and phages. In this study, we compared two genomes of A. baumannii clinical
strains isolated in 2000 (ST-2_clon_2000) and 2010 (ST-2_clon_2010) from GenBank project PRJNA308422
Chaotic dynamics around astrophysical objects with nonisotropic stresses
The existence of chaotic behavior for the geodesics of the test particles
orbiting compact objects is a subject of much current research. Some years ago,
Gu\'eron and Letelier [Phys. Rev. E \textbf{66}, 046611 (2002)] reported the
existence of chaotic behavior for the geodesics of the test particles orbiting
compact objects like black holes induced by specific values of the quadrupolar
deformation of the source using as models the Erez--Rosen solution and the Kerr
black hole deformed by an internal multipole term. In this work, we are
interesting in the study of the dynamic behavior of geodesics around
astrophysical objects with intrinsic quadrupolar deformation or nonisotropic
stresses, which induces nonvanishing quadrupolar deformation for the
nonrotating limit. For our purpose, we use the Tomimatsu-Sato spacetime [Phys.
Rev. Lett. \textbf{29} 1344 (1972)] and its arbitrary deformed generalization
obtained as the particular vacuum case of the five parametric solution of Manko
et al [Phys. Rev. D 62, 044048 (2000)], characterizing the geodesic dynamics
throughout the Poincar\'e sections method. In contrast to the results by
Gu\'eron and Letelier we find chaotic motion for oblate deformations instead of
prolate deformations. It opens the possibility that the particles forming the
accretion disk around a large variety of different astrophysical bodies
(nonprolate, e.g., neutron stars) could exhibit chaotic dynamics. We also
conjecture that the existence of an arbitrary deformation parameter is
necessary for the existence of chaotic dynamics.Comment: 7 pages, 5 figure
Equatorial symmetry/antisymmetry of stationary axisymmetric electrovac spacetimes
Two theorems are proved concerning how stationary axisymmetric electrovac
spacetimes that are equatorially symmetric or equatorially antisymmetric can be
characterized correctly in terms of the Ernst potentials \E and or in
terms of axis-data.Comment: 8 page
Realistic Exact Solution for the Exterior Field of a Rotating Neutron Star
A new six-parametric, axisymmetric and asymptotically flat exact solution of
Einstein-Maxwell field equations having reflection symmetry is presented. It
has arbitrary physical parameters of mass, angular momentum, mass--quadrupole
moment, current octupole moment, electric charge and magnetic dipole, so it can
represent the exterior field of a rotating, deformed, magnetized and charged
object; some properties of the closed-form analytic solution such as its
multipolar structure, electromagnetic fields and singularities are also
presented. In the vacuum case, this analytic solution is matched to some
numerical interior solutions representing neutron stars, calculated by Berti &
Stergioulas (Mon. Not. Roy. Astron. Soc. 350, 1416 (2004)), imposing that the
multipole moments be the same. As an independent test of accuracy of the
solution to describe exterior fields of neutron stars, we present an extensive
comparison of the radii of innermost stable circular orbits (ISCOs) obtained
from Berti & Stergioulas numerical solutions, Kerr solution (Phys. Rev. Lett.
11, 237 (1963)), Hartle & Thorne solution (Ap. J. 153, 807, (1968)), an
analytic series expansion derived by Shibata & Sasaki (Phys. Rev. D. 58 104011
(1998)) and, our exact solution. We found that radii of ISCOs from our solution
fits better than others with realistic numerical interior solutions.Comment: 13 pages, 13 figures, LaTeX documen
Fíbulas de codo tipo Huelva de Montejícar, Granada
They are made known two fíbulas of elbow protohistorics, originating from the deposit of the Allozos, in Montejícar, of the didn't exist concrete referring of township prior to the iberians. This contribution extends the evidence of these fíndings metall in the southeast peninsular, supporting the hypothesis of a mining of transformation local, to the rnargin of the developments of the Baja Andalucía, in what were Tartessos. The analysis of composition of the fíbulas, of type Huelva, show the survival of a tradition craft that sinks their origins in the Late/Middle Bronze, with the maintenance of sorne developments technicals that have been known lost from the apparent argaric crisis. The novelty of the discovery explains the deceit on such crisis, outlining by against the evolution of the substratum toward developments economics and, perhaps social, that explain the Final Bronze and his real importance.Se dan a conocer dos fíbulas de codo protohistóricas, procedentes del yacimiento de Los Allozos, en Montejícar, del que no había evidencias concretas de poblamiento anteriores a lo ibérico. Esta aportación amplía el referente de estos hallazgos metálicos en el sureste peninsular, apoyando la hipótesis de una minería de transformación local, al margen de los desarrollos de la Baja Andalucía, en lo que fuera Tartessos. Los análisis compositivos de las fíbulas, de tipo Huelva, muestran la pervivencia de una tradición artesana que hunde sus raíces en el Bronce Tardío/Medio, con el mantenimiento de unos caracteres técnicos que se creían perdidos desde la aparente crisis argárica. La novedad del descubrimiento ilustraría la falacia sobre tal crisis, planteando por contra la evolución del sustrato hacia desenvolvimientos económicos y, quizá sociales, que explican el Bronce Final y su verdadera importancia
Sequencing of Vellozia Spp. genomes to understand drought tolerance and phosphorus acquisition in angiosperms.
PE1164. PAG 2019
Frame dragging, vorticity and electromagnetic fields in axially symmetric stationary spacetimes
We present a general study about the relation between the vorticity tensor
and the Poynting vector of the electromagnetic field for axially symmetric
stationary electrovacuum metrics. The obtained expressions allow to understand
the role of the Poynting vector in the dragging of inertial frames. The
particular case of the rotating massive charged magnetic dipole is analyzed in
detail. In addition, the electric and magnetic parts of the Weyl tensor are
calculated and the link between the later and the vorticity is established.
Then we show that, in the vacuum case, the necessary and sufficient condition
for the vanishing of the magnetic part is that the spacetime be static.Comment: 16 pages Latex. Some minor changes in the text and typos correcte
Relationship Between the Quorum Network (Sensing/Quenching) and Clinical Features of Pneumonia and Bacteraemia Caused by A. baumannii
Acinetobacter baumannii (Ab) is one of the most important pathogens associated
with nosocomial infections, especially pneumonia. Interest in the Quorum network,
i.e., Quorum Sensing (QS)/Quorum Quenching (QQ), in this pathogen has grown
in recent years. The Quorum network plays an important role in regulating diverse
virulence factors such as surface motility and bacterial competition through the
type VI secretion system (T6SS), which is associated with bacterial invasiveness.
In the present study, we investigated 30 clinical strains of A. baumannii isolated in
the “II Spanish Study of A. baumannii GEIH-REIPI 2000-2010” (Genbank Umbrella
Bioproject PRJNA422585), a multicentre study describing the relationship between the
Quorum network in A. baumannii and the development of pneumonia and associated
bacteraemia. Expression of the aidA gene (encoding the AidA protein, QQ enzyme) was
lower (P < 0.001) in strains of A. baumannii isolated from patients with bacteraemic
pneumonia than in strains isolated from patients with non-bacteraemic pneumonia.
Moreover, aidA expression in the first type of strain was not regulated in the presence
of environmental stress factors such as the 3-oxo-C12-HSL molecule (substrate of AidA
protein, QQ activation) or H2O2 (inhibitor of AidA protein, QS activation). However, in the
A. baumannii strains isolated from patients with non-bacteraemic pneumonia, aidA gene
expression was regulated by stressors such as 3-oxo-C12-HSL and H2O2. In an in vivo
Galleria mellonella model of A. baumannii infection, the A. baumannii ATCC 17978 strain
was associated with higher mortality (100% at 24 h) than the mutant, abaI-deficient, strain (carrying a synthetase enzyme of Acyl homoserine lactone molecules) (70% at 24 h).
These data suggest that the QS (abaR and abaI genes)/QQ (aidA gene) network affects
the development of secondary bacteraemia in pneumonia patients and also the virulence
of A. baumannii.National Plan for Scientific ResearchTechnological Development and Innovation PI16/01163ISCIII-Deputy General Directorate for Evaluation and Promotion of Research-European Regional Development Fund A way of Making EuropeInstituto de Salud Carlos IIIMiguel Servet Research Programme SERGAS and ISCIIIXunta de Galicia (GAIN, Axencia de Innovación
Quantum Driven Dissipative Parametric Oscillator in a Blackbody Radiation Field
We consider the general open system problem of a charged quantum oscillator
confined in a harmonic trap, whose frequency can be arbitrarily modulated in
time, that interacts with both an incoherent quantized (blackbody) radiation
field and with an arbitrary coherent laser field. We assume that the oscillator
is initially in thermodynamic equilibrium with its environment, a
non-factorized initial density matrix of the system and the environment, and
that at the modulation of the frequency, the coupling to the incoherent
and the coherent radiation are switched on. The subsequent dynamics, induced by
the presence of the blackbody radiation and the laser field, is studied in the
framework of the influence functional approach. This approach allows
incorporating, in \emph{analytic closed formulae}, the non-Markovian character
of the oscillator-environment interaction at any temperature as well the
non-Markovian character of the blackbody radiation and its zero-point
fluctuations. Expressions for the time evolution of the covariance matrix
elements of the quantum fluctuations and the reduced density-operator are
obtained.Comment: 11 pages. It matches the published versio
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