1,200 research outputs found
Prevalence of Type VI Secretion System in Spanish Campylobacter jejuni Isolates.
Infections from Campylobacter jejuni pose a serious public health problem and are now considered the leading cause of foodborne bacterial gastroenteritis throughout the world. Sequencing of C. jejuni genomes has previously allowed a number of loci to be identified, which encode virulence factors that aid survival and pathogenicity. Recently, a Type VI secretion system (T6SS) consisting of 13 conserved genes was described in C. jejuni strains and recognised to promote pathogenicity and adaptation to the environment. In this study, we determined the presence of this T6SS in 63 Spanish C. jejuni isolates from the food chain and urban effluents using whole-genome sequencing. Our findings demonstrated that nine (14%) strains harboured the 13 ORFs found in prototype strain C. jejuni 108. Further studies will be necessary to determine the prevalence and importance of T6SS-positive C. jejuni strains
Aptitud clínica del médico familiar ante la atención primaria de depresión en embarazadas
Introducción: La depresión es un trastorno que ocurre mayormente en mujeres, esto aunado con la experiencia del embarazo, produce un grado elevado de estrés y compete al primer contacto de la embarazada detectar padecimientos que conformen un riesgo para la gestante.Objetivo: Determinar el nivel de aptitud clínica del médico familiar ante el diagnóstico de depresión en embarazadas en el primer nivel de atención en la UMF 1 en Cd Obregón, Sonora.Materiales y métodos: Estudio observacional, transversal analítico, con la participación de 28 médicos familiares, a quienes se les aplicó un instrumento de evaluación de aptitud clínica de depresión en el embarazo, que tiene confiabilidad a través de la fórmula Kuder-Richardson de 0.78, consta de 4 casos clínico, 138 reactivos en total y valora diversos indicadores.Resultados: De los 28 médicos participantes 4 (14.28%) tuvieron nivel de aptitud clínico alto, 23 (82.13%) tuvieron nivel regular, y 1 (3.5%) se encontró en nivel bajo. La asociación con el género obtuvo p=0.593, para la edad fue p=0.752 y el estado civil tuvo p=0.517.Conclusión: El nivel de aptitud clínica de los médicos familiares fue regular y no se encontraron asociaciones con las variables: género, edad o antigüedad
Calibration of semi-analytic models of galaxy formation using Particle Swarm Optimization
We present a fast and accurate method to select an optimal set of parameters
in semi-analytic models of galaxy formation and evolution (SAMs). Our approach
compares the results of a model against a set of observables applying a
stochastic technique called Particle Swarm Optimization (PSO), a self-learning
algorithm for localizing regions of maximum likelihood in multidimensional
spaces that outperforms traditional sampling methods in terms of computational
cost. We apply the PSO technique to the SAG semi-analytic model combined with
merger trees extracted from a standard CDM N-body simulation. The
calibration is performed using a combination of observed galaxy properties as
constraints, including the local stellar mass function and the black hole to
bulge mass relation. We test the ability of the PSO algorithm to find the best
set of free parameters of the model by comparing the results with those
obtained using a MCMC exploration. Both methods find the same maximum
likelihood region, however the PSO method requires one order of magnitude less
evaluations. This new approach allows a fast estimation of the best-fitting
parameter set in multidimensional spaces, providing a practical tool to test
the consequences of including other astrophysical processes in SAMs.Comment: 11 pages, 4 figures, 1 table. Accepted for publication in ApJ.
Comments are welcom
How accurate is it to update the cosmology of your halo catalogues?
We test and present the application of the full rescaling method by Angulo & White to change the cosmology of halo catalogues in numerical simulations for cosmological parameter search using semi-analytic galaxy properties. We show that a reduced form of the method can be applied to small simulations with box side of ~50h-1Mpc or smaller without loss of accuracy. We perform statistical tests on the accuracy of the properties of rescaled individual haloes, and also on the rescaled population as a whole. We find that individual positions and velocities are recovered with almost no detectable biases, but with a scatter that increases slightly with the size of the simulation box when using the full method. The dispersion in the recovered halo mass does not seem to depend on the resolution of the simulation. Regardless of the halo mass, the individual accretion histories, spin parameter evolution and fraction of mass in substructures are remarkably well recovered. In particular, in order to obtain a more accurate estimate of the halo virial mass, it was necessary to apply an additional correction due to the change in the virial overdensity and the estimate of its effect on a Navarro, Frenk & White (NFW) virial mass. The mass of rescaled haloes can be underestimated (overestimated) for negative (positive) variations of either σ8 or in a way that does not depend on the halo mass. Statistics of abundances and correlation functions of haloes also show small biases of <10 per cent when moving away from the base simulation by up to two times the uncertainty in the WMAP7 cosmological parameters. The merger tree properties related to the final galaxy population in haloes also show small biases; the time since the last major merger, the assembly time-scale, and a time-scale related to the stellar ages show correlated biases which indicate that the spectral shapes of galaxies would only be affected by global age changes of ~150Myr, i.e. relatively small shifts in their broad-band colours. We show some of these biases for different separations in the cosmological parameters with respect to the desired cosmology so that these can be used to estimate the expected accuracy of the resulting halo population. We also present a way to construct grids of simulations to provide a stable accuracy across the versus σ8 parameter space.Instituto de Astrofísica de La Plat
Free energy of colloidal particles at the surface of sessile drops
The influence of finite system size on the free energy of a spherical
particle floating at the surface of a sessile droplet is studied both
analytically and numerically. In the special case that the contact angle at the
substrate equals a capillary analogue of the method of images is
applied in order to calculate small deformations of the droplet shape if an
external force is applied to the particle. The type of boundary conditions for
the droplet shape at the substrate determines the sign of the capillary
monopole associated with the image particle. Therefore, the free energy of the
particle, which is proportional to the interaction energy of the original
particle with its image, can be of either sign, too. The analytic solutions,
given by the Green's function of the capillary equation, are constructed such
that the condition of the forces acting on the droplet being balanced and of
the volume constraint are fulfilled. Besides the known phenomena of attraction
of a particle to a free contact line and repulsion from a pinned one, we
observe a local free energy minimum for the particle being located at the drop
apex or at an intermediate angle, respectively. This peculiarity can be traced
back to a non-monotonic behavior of the Green's function, which reflects the
interplay between the deformations of the droplet shape and the volume
constraint.Comment: 24 pages, 19 figure
Horizontal flow fields observed in Hinode G-band images II. Flow fields in the final stages of sunspot decay
We present a subset of multi-wavelengths observations obtained with the
Japanese Hinode mission, the Solar Dynamics Observatory (SDO), and the Vacuum
Tower Telescope (VTT) at Observatorio del Teide, Tenerife, Spain during the
time period from 2010 November 18-23. Horizontal proper motions were derived
from G-band and Ca II H images, whereas line-of-sight velocities were extracted
from VTT Echelle H-alpha 656.28 nm spectra and Fe I 630.25 nm spectral data of
the Hinode/Spectro-Polarimeter, which also provided three-dimensional magnetic
field information. The Helioseismic and Magnetic Imager on board SDO provided
continuum images and line-of-sight magnetograms as context for the
high-resolution observations for the entire disk passage of the active region.
We have performed a quantitative study of photospheric and chromospheric flow
fields in and around decaying sunspots. In one of the trailing sunspots of
active region NOAA 11126, we observed moat flow and moving magnetic features
(MMFs), even after its penumbra had decayed. We also noticed a superpenumbral
structure around this pore. MMFs follow well-defined, radial paths from the
spot all the way to the border of a supergranular cell surrounding the spot. In
contrast, flux emergence near the other sunspot prevented it from establishing
such well ordered flow patterns, which could even be observed around a tiny
pore of just 2 Mm diameter. After the disappearance of the sunspots/pores a
coherent patch of abnormal granulation remained at their location, which was
characterized by more uniform horizontal proper motions, low divergence values,
and diminished photospheric Doppler velocities. This region, thus, differs
significantly from granulation and other areas covered by G-band bright points.
We conclude that this peculiar flow pattern is a signature of sunspot decay and
the dispersal of magnetic flux.Comment: 13 pages, 11 figures, accepted for publication in Astronomy and
Astrophysic
How accurate is it to update the cosmology of your halo catalogues?
We test and present the application of the full rescaling method by Angulo &
White (2010) to change the cosmology of halo catalogues in numerical
simulations for cosmological parameter search using semi-analytic galaxy
properties. We show that a reduced form of the method can be applied in small
simulations with box side of ~50/h Mpc. We perform statistical tests on the
accuracy of the properties of rescaled individual haloes, and also on the
rescaled population as a whole. We find that individual positions and
velocities are recovered with almost no detectable biases. The dispersion in
the recovered halo mass does not seem to depend on the resolution of the
simulation. Regardless of the halo mass, the individual accretion histories,
spin parameter evolution and fraction of mass in substructures are well
recovered. The mass of rescaled haloes can be underestimated (overestimated)
for negative (positive) variations of either sigma_8 or Omega_m, in a way that
does not depend on the halo mass. Statistics of abundances and correlation
functions of haloes show also small biases of <10 percent when moving away from
the base simulation by up to 2 times the uncertainty in the WMAP7 cosmological
parameters. The merger tree properties related to the final galaxy population
in haloes also show small biases; the time since the last major merger, the
assembly time-scale, and a time-scale related to the stellar ages show
correlated biases which indicate that the spectral shapes of galaxies would
only be affected by global age changes of ~150 Myr. We show some of these
biases for different separations in the cosmological parameters with respect to
the desired cosmology so that these can be used to estimate the expected
accuracy of the resulting halo population. We also present a way to construct
grids of simulations to provide stable accuracy across the Omega_m vs sigma_8
parameter space.Comment: 14 pages, 2 tables, 10 figures. Accepted for publication in MNRA
Stevens-Johnson syndrome and toxic epidermal necrolysis: a review
Stevens Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are considered a single entity with variability in the extent of the lesions, characterized by erythema multiforme that may involve mucosa. Severe cutaneous reactions secondary to medications are classified according to the area of epidermal detachment. The activation of cytotoxic T cells and macrophages is mediated mainly by IL-2 and interferon gamma secreted by Th1 lymphocytes, and the activation of eosinophils and B lymphocytes in IgE is mediated by secreted IL-4, IL-5, IL-10 and IL13 by B lymphocytes. The topography of SJS is predominantly central, affecting the trunk and sometimes a generalized dissemination is shown that affects a body surface area of less than 10%, characterized by irregular violaceous erythematous macules of target shooting, which can form confluent blisters. TEN is characterized by a skin detachment greater than 30% of the body surface, whose predominant lesion is diffuse erythema with individual macules, which give rise to detachment surfaces greater than 5 cm. The treatment is symptomatic, nonspecific, and aimed at avoiding complications, carried out in specialized intensive care units, due to ignorance of the pathogenesis. Integral management with different therapeutic alternatives can represent a crucial part in the multisystemic management of SJS and TEN
PyroTyping, a novel pyrosequencing-based assay for Mycobacterium tuberculosis genotyping
We developed a novel method, PyroTyping, for discrimination of Mycobacterium tuberculosis isolates combining pyrosequencing and IS6110 polymorphism. A total of 100 isolates were analysed with IS6110-restriction fragment length polymorphism (RFLP), spoligotyping, mycobacterial interspersed repetitive units - variable number tandem repeats (MIRU-VNTR), and PyroTyping. PyroTyping results regarding clustering or discrimination of the isolates were highly concordant with the other typing methods performed. PyroTyping is more rapid than RFLP and presents the same discriminatory power, thus, it may be useful for taking timely decisions for tuberculosis control
Comprehensive characterization of a novel, oncogenic and targetable SEPTIN6::ABL2 fusion in T-ALL
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