29,352 research outputs found
Dynamics of quantum correlations and linear entropy in a multi-qubit-cavity system
We present a theoretical study of the relationship between entanglement and
entropy in multi-qubit quantum optical systems. Specifically we investigate
quantitative relations between the concurrence and linear entropy for a
two-qubit mixed system, implemented as two two-level atoms interacting with a
single-mode cavity field. The dynamical evolutions of the entanglement and
entropy, are controlled via time-dependent cavity-atom couplings. Our
theoretical findings lead us to propose an alternative measure of entanglement,
which could be used to develop a much needed correlation measure for more
general multi-partite quantum systems.Comment: New discussions on the generality of entanglement-entropy
relationship, one new reference, and other minor changes. 10 pages, 6
figures, accepted for publication in J.Opt. B: "Special Issue on Fluctuations
& Noise in Photonics & Quantum Optics.
El rol del control personal en la función paliativa de la justificación del sistema entre la población indígena y no indígena de estudiantes peruanos
Indexación: Scopus.In this article we propose a mediation model for the association between system justification and psychological well-being (i.e., the palliative function of ideology), based on system justification theory and compensatory control theory. Specifically, we argue that endorsing system-justifying beliefs leads to increased perceived personal control, which in turn predicts higher well-being. We used a convenience sample of students from two Peruvian universities. The results showed that system justification was related to general psychological well-being and personal control. In addition, indigenous students rated lower on system justification, general psychological well-being, self-esteem and personal control. Next, we found that the association between system justification and general psychological well-being was stronger among indigenous students, and this relationship was partially mediated by personal control. In addition, we showed that the mediation model is moderated by ethnicity, so that personal control is a mediator only among non-indigenous participants. We conclude that personal control is a mechanism involved in the palliative function of ideology among this group. Finally, we discuss possible explanations for the mechanisms involved in the palliative function of ideology among low-status individuals. © 2018, © 2018 Fundacion Infancia y Aprendizaje.En este artículo se propone un modelo de mediación de las
relaciones entre la justificación del sistema y el bienestar psicológico (i.e.,
la función paliativa de la ideología) basado en las teorías de la justificación
del sistema y del control compensatorio. En concreto, se propone que la
adopción de creencias justificativas del sistema produce un aumento del
control personal percibido que, a su vez, predice niveles más elevados de bienestar. En este estudio se utilizó una muestra por conveniencia de estudiantes
provenientes de dos universidades peruanas. Los resultados muestran
que la justificación del sistema está relacionada con el bienestar psicológico
general y con el control personal. Además, los estudiantes indígenas mostraron
niveles más reducidos de justificación del sistema, bienestar
psicológico general, autoestima y control personal. También se observó que
la relación entre la justificación del sistema y el bienestar psicológico general
era más fuerte entre los estudiantes indígenas y que el control personal
mediaba parcialmente en esta relación. Asimismo, mostramos que la etnicidad
es un factor moderador del modelo de mediación, por lo que el control
personal es un mediador únicamente entre los participantes no indígenas. El
estudio concluye que el control personal es un mecanismo que interviene en
la función paliativa de la ideología en este grupo. Por último, se discuten
posibles explicaciones de los mecanismos implicados en la función paliativa
de la ideología entre individuos de estatus social bajo.https://www.tandfonline.com/doi/full/10.1080/02134748.2018.153765
Comportamento de duas variedades de algodoeiro depois da inoculação com Cotton leaf roll mosaic virus.
Com o objetivo de estudar a distribuição do vírus em plantas de algodão, foi desenvolvido um experimento na Embrapa Arroz e Feijão, em Santo Antônio de Goiás, utilizando-se as cultivares de algodão BRS 293 (resistente) e FM 966 (suscetível).Pôster - graduação
Mediastinal Mass in a Patient with Colorectal Cancer: A Diagnostic Challenge
The differential diagnosis of mediastinal masses involves many benign and malignant conditions, such as lymphadenopathies and cystic lesions. Metastatic mediastinal adenopathies are usually due to lung, esophagus, and stomach cancer and, rarely, due to colorectal cancer. Gastrointestinal duplication cysts are uncommon inherited lesions usually diagnosed during childhood and may involve the esophagus in 20% of cases. In adults, they are usually asymptomatic and diagnosed incidentally. We report the case of a 54-year-old male who recently underwent sigmoidectomy due to an obstructive colon adenocarcinoma. Staging computed tomography scan showed a hypodense lesion in the posterior mediastinum suggestive of metastatic adenopathy. Endoscopic ultrasound revealed a homogeneous and hypoechogenic lesion with intramural location in the upper esophagus, suggestive of a duplication esophageal cyst. Given the oncologic background and to exclude metastatic disease, endoscopic ultrasound-guided fine needle aspiration was performed, and a mucinous fluid was aspirated. The cytologic examination supported the ultrasonographic diagnostic hypothesis. This case highlights the role of endoscopic ultrasound in the differential diagnosis of mediastinal masses, particularly in oncologic patients, in order to rule out more ominous lesions.info:eu-repo/semantics/publishedVersio
Non-vascular interventional procedures: effective dose to patient and equivalent dose to abdominal organs by means of dicom images and Monte Carlo simulation
This study evaluates X-ray exposure in patient undergoing abdominal extra-vascular interventional procedures by means of Digital Imaging and COmmunications in Medicine (DICOM) image headers and Monte Carlo simulation. The main aim was to assess the effective and equivalent doses, under the hypothesis of their correlation with the dose area product (DAP) measured during each examination. This allows to collect dosimetric information about each patient and to evaluate associated risks without resorting to in vivo dosimetry. The dose calculation was performed in 79 procedures through the Monte Carlo simulator PCXMC (A PC-based Monte Carlo program for calculating patient doses in medical X-ray examinations), by using the real geometrical and dosimetric irradiation conditions, automatically extracted from DICOM headers. The DAP measurements were also validated by using thermoluminescent dosimeters on an anthropomorphic phantom. The expected linear correlation between effective doses and DAP was confirmed with an R(2) of 0.974. Moreover, in order to easily calculate patient doses, conversion coefficients that relate equivalent doses to measurable quantities, such as DAP, were obtained
Energy spectrum and Landau levels in bilayer graphene with spin-orbit interaction
We present a theoretical study of the bandstructure and Landau levels in
bilayer graphene at low energies in the presence of a transverse magnetic field
and Rashba spin-orbit interaction in the regime of negligible trigonal
distortion. Within an effective low energy approach (L\"owdin partitioning
theory) we derive an effective Hamiltonian for bilayer graphene that
incorporates the influence of the Zeeman effect, the Rashba spin-orbit
interaction, and inclusively, the role of the intrinsic spin-orbit interaction
on the same footing. Particular attention is spent to the energy spectrum and
Landau levels. Our modeling unveil the strong influence of the Rashba coupling
in the spin-splitting of the electron and hole bands. Graphene
bilayers with weak Rashba spin-orbit interaction show a spin-splitting linear
in momentum and proportional to , but scales inversely proportional
to the interlayer hopping energy . However, at robust spin-orbit
coupling the energy spectrum shows a strong warping behavior near
the Dirac points. We find the bias-induced gap in bilayer graphene to be
decreasing with increasing Rashba coupling, a behavior resembling a topological
insulator transition. We further predict an unexpected assymetric
spin-splitting and crossings of the Landau levels due to the interplay between
the Rashba interaction and the external bias voltage. Our results are of
relevance for interpreting magnetotransport and infrared cyclotron resonance
measurements, including also situations of comparatively weak spin-orbit
coupling.Comment: 25 pages, 5 figure
Hidden Conformal Symmetry of the Reissner-Nordstr{\o}m Black Holes
Motivated by recent progresses in the holographic descriptions of the Kerr
and Reissner-Nordstr{\o}m (RN) black holes, we explore the hidden conformal
symmetry of nonextremal uplifted 5D RN black hole by studying the near horizon
wave equation of a massless scalar field propagating in this background.
Similar to the Kerr black hole case, this hidden symmetry is broken by the
periodicity of the associated angle coordinate in the background geometry, but
the results somehow testify the dual CFT description of the nonextremal RN
black holes. The duality is further supported by matching of the entropies and
absorption cross sections calculated from both CFT and gravity sides.Comment: 14 pages, no figur
Duodenal gastrointestinal stromal tumor and endoscopic ultrasound
Duodenal gastrointestinal stromal tumors (GISTs) are a very rare condition. The pre-operative diagnosis can be a challenge but it is very important because GISTs have singularities that differ from other tumors and their location in the duodenum itself can have a major role in the choice of the surgical approach. We present two cases of duodenal GISTs where endoscopic ultrasound had a single role in their management, namely allowing the possibility to obtain material for immunocytochemical pre-operative diagnosis and regarding the precise relation to the papilla of Vater. The patients were operated and histological examination confirmed the diagnosis in both cases
Correlations of Globular Cluster Properties: Their Interpretations and Uses
Correlations among the independently measured physical properties of globular
clusters (GCs) can provide powerful tests for theoretical models and new
insights into their dynamics, formation, and evolution. We review briefly some
of the previous work, and present preliminary results from a comparative study
of GC correlations in the Local Group galaxies. The results so far indicate
that these diverse GC systems follow the same fundamental correlations,
suggesting a commonality of formative and evolutionary processes which produce
them.Comment: An invited review, to appear in "New Horizons in Globular Cluster
Astronomy", eds. G. Piotto, G. Meylan, S.G. Djorgovski, and M. Riello, ASPCS,
in press (2003). Latex file, 8 pages, 5 eps figures, style files include
The formation of planetary disks and winds: an ultraviolet view
Planetary systems are angular momentum reservoirs generated during star
formation. This accretion process produces very powerful engines able to drive
the optical jets and the molecular outflows. A fraction of the engine energy is
released into heating thus the temperature of the engine ranges from the 3000K
of the inner disk material to the 10MK in the areas where magnetic reconnection
occurs. There are important unsolved problems concerning the nature of the
engine, its evolution and the impact of the engine in the chemical evolution of
the inner disk. Of special relevance is the understanding of the shear layer
between the stellar photosphere and the disk; this layer controls a significant
fraction of the magnetic field building up and the subsequent dissipative
processes ougth to be studied in the UV.
This contribution focus on describing the connections between 1 Myr old suns
and the Sun and the requirements for new UV instrumentation to address their
evolution during this period. Two types of observations are shown to be needed:
monitoring programmes and high resolution imaging down to, at least,
milliarsecond scales.Comment: Accepted for publication in Astrophysics and Space Science 9 figure
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