1,180 research outputs found
Malassezia furfur bloodstream infection: still a diagnostic challenge in clinical practice
The opportunistic fungus Malassezia furfur (M. furfur) can cause either cutaneous or systemic infections. We report a case of M. furfur fungemia in a 22-year-old male with T-cell Acute Lymphoblastic Leukemia (T-ALL) who developed concomitant Bacillus cereus (B. cereus) septicemia. The fungal infection was diagnosed by microscopic examination and culture-based methods, while automated blood culture systems and molecular approaches failed in identifying the fungus. Despite appropriate therapy, the patient died 18 days after the hospitalization
Charring effects on stable carbon and nitrogen isotope values on C4 plants: Inferences for archaeological investigations
Experimental studies demonstrated that charring affects stable isotope values of plant remains. Therefore, it is necessary to consider the impact of charring to reliably interpret δ13C and δ15N values in archaeobotanical remains before using this approach to reconstruct past water management, paleoclimatic changes, and infer paleodietary patterns. Research so far has focused mostly on C3 plants while the charring effect on C4 plants is less understood. This study explored the effects of charring on δ13C, δ15N, %C, %N, and C:N in grains of two C4 species, Sorghum bicolor (L.) Moench (NADP-ME) and Cenchrus americanus (L.) Morrone (heterotypic synonym Pennisetum glaucum (L.) R.Br.) (NAD-ME), grown under the same controlled environmental conditions (watering, light, atmospheric humidity). Sorghum and pearl millet grains were charred from 1 to 3 h at 200–300 °C. Comparing first the uncharred grains, the results show that sorghum has lower δ15N and higher δ13C values than pearl millet. This evidence is also recorded in the charred grains. The charring experiments indicate that the temperature to which the grains are exposed has a higher impact than time on the preservation, mass loss, %C, %N, C:N, and δ13C and δ15N values. Every 50 °C of increase resulted in significant increases of δ15N (+0.37‰) and of δ13C (+0.06‰) values. Increasing the duration of charring to 3 h resulted in significant changes of δ15N (+0.17‰) and no significant changes for δ13C (−0.04‰) values. The average charring effects estimated in our experiment is 0.27‰ (95% CI between −0.02 and 0.56) for δ15N and −0.18‰ (95% CI between −0.30 and −0.06‰) for δ13C. Considering the average values, our data show that pearl millet is more affected by charring than sorghum; however, according to the standard deviations, sorghum shows a greater variability charring effect than pearl millet. This study provides new information to correctly assessing the isotopic values obtained from ancient C4 crops, providing a charring offset specific for C4 plants. Furthermore, it suggests that NAD-ME and NADP-ME species present isotopic differences under the same growing conditions and this must be taken into account in analytical works on ancient C4 crops.This work was funded by the ERC Staring Grant RAINDROPS (G.A. n 759800) under the Horizon 2020 program of the European Commission. CASEs is a Quality Research Group funded by the Government of Catalonia (SGR00950-2021)
The history of mass assembly of faint red galaxies in 28 galaxy clusters since z=1.3
We measure the relative evolution of the number of bright and faint (as faint
as 0.05 L*) red galaxies in a sample of 28 clusters, of which 16 are at 0.50<=
z<=1.27, all observed through a pair of filters bracketing the 4000 Angstrom
break rest-frame. The abundance of red galaxies, relative to bright ones, is
constant over all the studied redshift range, 0<z<1.3, and rules out a
differential evolution between bright and faint red galaxies as large as
claimed in some past works. Faint red galaxies are largely assembled and in
place at z=1.3 and their deficit does not depend on cluster mass, parametrized
by velocity dispersion or X-ray luminosity. Our analysis, with respect to
previous one, samples a wider redshift range, minimizes systematics and put a
more attention to statistical issues, keeping at the same time a large number
of clusters.Comment: MNRAS, 386, 1045. Half a single sentence (in sec 4.4) change
Bayesian Inference in Processing Experimental Data: Principles and Basic Applications
This report introduces general ideas and some basic methods of the Bayesian
probability theory applied to physics measurements. Our aim is to make the
reader familiar, through examples rather than rigorous formalism, with concepts
such as: model comparison (including the automatic Ockham's Razor filter
provided by the Bayesian approach); parametric inference; quantification of the
uncertainty about the value of physical quantities, also taking into account
systematic effects; role of marginalization; posterior characterization;
predictive distributions; hierarchical modelling and hyperparameters; Gaussian
approximation of the posterior and recovery of conventional methods, especially
maximum likelihood and chi-square fits under well defined conditions; conjugate
priors, transformation invariance and maximum entropy motivated priors; Monte
Carlo estimates of expectation, including a short introduction to Markov Chain
Monte Carlo methods.Comment: 40 pages, 2 figures, invited paper for Reports on Progress in Physic
The Bjorken sum rule with Monte Carlo and Neural Network techniques
Determinations of structure functions and parton distribution functions have
been recently obtained using Monte Carlo methods and neural networks as
universal, unbiased interpolants for the unknown functional dependence. In this
work the same methods are applied to obtain a parametrization of polarized Deep
Inelastic Scattering (DIS) structure functions. The Monte Carlo approach
provides a bias--free determination of the probability measure in the space of
structure functions, while retaining all the information on experimental errors
and correlations. In particular the error on the data is propagated into an
error on the structure functions that has a clear statistical meaning. We
present the application of this method to the parametrization from polarized
DIS data of the photon asymmetries and from which we determine
the structure functions and , and discuss the
possibility to extract physical parameters from these parametrizations. This
work can be used as a starting point for the determination of polarized parton
distributions.Comment: 24 pages, 6 figure
Effects of age and gender on neural correlates of emotion imagery
Mental imagery is part of people's own internal processing and plays an important role in everyday life, cognition and pathology. The neural network supporting mental imagery is bottom-up modulated by the imagery content. Here, we examined the complex associations of gender and age with the neural mechanisms underlying emotion imagery. We assessed the brain circuits involved in emotion mental imagery (vs. action imagery), controlled by a letter detection task on the same stimuli, chosen to ensure attention to the stimuli and to discourage imagery, in 91 men and women aged 14–65 years using fMRI. In women, compared with men, emotion imagery significantly increased activation within the right putamen, which is involved in emotional processing. Increasing age, significantly decreased mental imagery-related activation in the left insula and cingulate cortex, areas involved in awareness of ones' internal states, and it significantly decreased emotion verbs-related activation in the left putamen, which is part of the limbic system. This finding suggests a top-down mechanism by which gender and age, in interaction with bottom-up effect of type of stimulus, or directly, can modulate the brain mechanisms underlying mental imagery
Neural Network Parametrization of Deep-Inelastic Structure Functions
We construct a parametrization of deep-inelastic structure functions which
retains information on experimental errors and correlations, and which does not
introduce any theoretical bias while interpolating between existing data
points. We generate a Monte Carlo sample of pseudo-data configurations and we
train an ensemble of neural networks on them. This effectively provides us with
a probability measure in the space of structure functions, within the whole
kinematic region where data are available. This measure can then be used to
determine the value of the structure function, its error, point-to-point
correlations and generally the value and uncertainty of any function of the
structure function itself. We apply this technique to the determination of the
structure function F_2 of the proton and deuteron, and a precision
determination of the isotriplet combination F_2[p-d]. We discuss in detail
these results, check their stability and accuracy, and make them available in
various formats for applications.Comment: Latex, 43 pages, 22 figures. (v2) Final version, published in JHEP;
Sect.5.2 and Fig.9 improved, a few typos corrected and other minor
improvements. (v3) Some inconsequential typos in Tab.1 and Tab 5 corrected.
Neural parametrization available at http://sophia.ecm.ub.es/f2neura
Design and Test of a Forward Neutron Calorimeter for the ZEUS Experiment
A lead scintillator sandwich sampling calorimeter has been installed in the
HERA tunnel 105.6 m from the central ZEUS detector in the proton beam
direction. It is designed to measure the energy and scattering angle of
neutrons produced in charge exchange ep collisions. Before installation the
calorimeter was tested and calibrated in the H6 beam at CERN where 120 GeV
electrons, muons, pions and protons were made incident on the calorimeter. In
addition, the spectrum of fast neutrons from charge exchange proton-lucite
collisions was measured. The design and construction of the calorimeter is
described, and the results of the CERN test reported. Special attention is paid
to the measurement of shower position, shower width, and the separation of
electromagnetic showers from hadronic showers. The overall energy scale as
determined from the energy spectrum of charge exchange neutrons is compared to
that obtained from direct beam hadrons.Comment: 45 pages, 22 Encapsulated Postscript figures, submitted to Nuclear
Instruments and Method
Evolution of Group Galaxies from the First Red-Sequence Cluster Survey
We study the evolution of the red galaxy fraction (f_red) in 905 galaxy
groups with 0.15 < z < 0.52. The galaxy groups are identified by the
`probability Friends-of-Friends' algorithm from the first Red-Sequence Cluster
Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity
in the properties of the red-sequence of the group galaxies, indicating that
the luminous red-sequence galaxies in the groups are already in place by z~0.5
and that they have a formation epoch of z>2. In general, groups at lower
redshifts exhibit larger f_red than those at higher redshifts, showing a group
Butcher-Oemler effect. We investigate the evolution of f_red by examining its
dependence on four parameters, which can be classified as one intrinsic and
three environmental: galaxy stellar mass (M_*), total group stellar
mass(M_{*,grp}, a proxy for group halo mass), normalized group-centric radius
(r_grp), and local galaxy density (Sigma_5). We find that M_* is the dominant
parameter such that there is a strong correlation between f_red and galaxy
stellar mass. Furthermore, the dependence of f_red on the environmental
parameters is also a strong function of M_*. Massive galaxies (M_* > 10^11
M_sun) show little dependence of f_red on r_grp, M_{*,grp}, and Sigma_5 over
the redshift range. The dependence of f_red on these parameters is primarily
seen for galaxies with lower masses, especially for M_* < 10^{10.6} M_{sun}. We
observe an apparent `group down-sizing' effect, in that galaxies in lower-mass
halos, after controlling for galaxy stellar mass, have lower f_red. We find a
dependence of \fred on both \rgrp and \SigmaF after the other parameters are
controlled. At a fixed \rgrp, there is a significant dependence of f_red on
Sigma_5, while r_grp gradients of f_red are seen for galaxies in similar
Sigma_5 regions. This indicates .....Comment: ApJ accepte
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