7,258 research outputs found
Seasonal and pandemic influenza: the role of communication and preventive strategies
Appropriate, timely, and data-driven health information is a very important issue in preventive strategies against influenza. Intui- tively, a link between willingness to be vaccinated against seasonal influenza and against pandemic influenza exists, given the similarities in decision-making for this vaccine. International and national literature reviews suggest that progress has been made in order to incorporate and disseminate crisis risk communication principles into public health practice, as such investments in public health could be important for building capacity and practice which aid in the realization of countermeasures in response to a future pandemic and epidemic situation. This study emphasizes the lack of perception by Health Care Workers (HCWs) of the importance of being immunized against seasonal and pandemic influenza and the doubts concerning safety. In the future, particular efforts are needed during vaccination campaigns, to provide more information to HCWs and the general population regarding role and safety of such vaccines
A comparative study of experimental configurations in synchrotron pair distribution function
The identification and quantification of amorphous components and nanocrystalline phases
with very small crystal sizes, smaller than ~3 nm, within samples containing crystalline phases is
very challenging. However, this is important as there are several types of systems that contain these
matrices: building materials, glass-ceramics, some alloys, etc. The total scattering synchrotron pair
distribution function (PDF) can be used to characterize the local atomic order of the nanocrystalline
components and to carry out quantitative analyses in complex mixtures. Although the resolution in
momentum transfer space has been widely discussed, the resolution in the interatomic distance space
has not been discussed to the best of our knowledge. Here, we report synchrotron PDF data collected at
three beamlines in different experimental configurations and X-ray detectors. We not only discuss the
effect of the resolution in Q-space, Qmax ins of the recorded data and Qmax of the processed data, but we
also discuss the resolution in the interatomic distance (real) space. A thorough study of single-phase
crystalline nickel used as standard was carried out. Then, selected cement-related samples including
anhydrous tricalcium and dicalcium silicates, and pastes derived from the hydration of tricalcium
silicate and ye’elimite with bassanite were analyzed.This work is part of the PhD of Mr. Jesus D. Zea-Garcia. This work was supported by Spanish MINECO and FEDER [BIA2017-82391-R research project and I3 [IEDI-2016-0079] program]
Expression of telomeric repeat binding factor-1 in astroglial brain tumors
OBJECTIVE: In human somatic cells, telomeres shorten with successive cell divisions,
resulting in progressive genomic instability, altered gene expression, and cell death.
Recently, telomere-specific deoxyribonucleic acid-binding proteins, such as telomeric
repeat binding factor-1 (TRF1), have been proposed as candidates for the role of
molecules regulating telomerase activity, and they have been suggested to play key
roles in the maintenance of telomere function. The present study was designed to
assess TRF1 expression in human astroglial brain tumors and to speculate on the
clinical implications of its expression.
METHODS: Twenty flash-frozen surgical specimens obtained from adult patients who
underwent craniotomy for microsurgical tumor resection, histologically verified as
World Health Organization Grade II to IV astrocytomas, were used. Expression of
TRF1 in astrocytomas of different grades was studied by means of both immunohistochemical
and Western blotting analysis. The correlation between the extent of TRF1
expression and histological grading, performance status, and length of survival of
patients underwent statistical analyses.
RESULTS: TRF1 was expressed in all tumor samples. The level of its expression was
variable, decreasing from low-grade through high-grade astrocytomas (P 0.0032).
TRF1 expression correlated with the patient’s length of survival (P 0.001) and
performance status (P 0.001) and proved to be an independent indicator of length
of survival.
CONCLUSION: Our findings suggest that the loss of TRF1 expression capability, as a
result of down-regulation of TRF1 expression in malignant gliomas cells, may play a
role in the malignant progression of astroglial brain tumors
Momentum-resolved lattice dynamics of parent and electron-doped SrIrO
The mixing of orbital and spin character in the wave functions of the
iridates has led to predictions of strong couplings among their lattice,
electronic and magnetic degrees of freedom. As well as realizing a novel
spin-orbit assisted Mott-insulating ground state, the perovskite iridate
SrIrO has strong similarities with the cuprate LaCuO,
which on doping hosts a charge-density wave that appears intimately connected
to high-temperature superconductivity. These phenomena can be sensitively
probed through momentum-resolved measurements of the lattice dynamics, made
possible by meV-resolution inelastic x-ray scattering. Here we report the first
such measurements for both parent and electron-doped SrIrO. We find
that the low-energy phonon dispersions and intensities in both compounds are
well described by the same nonmagnetic density functional theory calculation.
In the parent compound, no changes of the phonons on magnetic ordering are
discernible within the experimental resolution, and in the doped compound no
anomalies are apparent due to charge-density waves. These measurements extend
our knowledge of the lattice properties of (SrLa)IrO
and constrain the couplings of the phonons to magnetic and charge order.Comment: 8 pages, 6 figures (+ 12 pages, 6 figures of supplemental material
Mott transition and collective charge pinning in electron doped Sr2IrO4
We studied the in-plane dynamic and static charge conductivity of electron
doped Sr2IrO4 using optical spectroscopy and DC transport measurements. The
optical conductivity indicates that the pristine material is an indirect
semiconductor with a direct Mott-gap of 0.55 eV. Upon substitution of 2% La per
formula unit the Mott-gap is suppressed except in a small fraction of the
material (15%) where the gap survives, and overall the material remains
insulating. Instead of a zero energy mode (or Drude peak) we observe a soft
collective mode (SCM) with a broad maximum at 40 meV. Doping to 10% increases
the strength of the SCM, and a zero-energy mode occurs together with metallic
DC conductivity. Further increase of the La substitution doesn't change the
spectral weight integral up to 3 eV. It does however result in a transfer of
the SCM spectral weight to the zero-energy mode, with a corresponding reduction
of the DC resistivity for all temperatures from 4 to 300 K. The presence of a
zero-energy mode signals that at least part of the Fermi surface remains
ungapped at low temperatures, whereas the SCM appears to be caused by pinning a
collective frozen state involving part of the doped electrons
{SelfPose}: {3D} Egocentric Pose Estimation from a Headset Mounted Camera
We present a solution to egocentric 3D body pose estimation from monocular
images captured from downward looking fish-eye cameras installed on the rim of
a head mounted VR device. This unusual viewpoint leads to images with unique
visual appearance, with severe self-occlusions and perspective distortions that
result in drastic differences in resolution between lower and upper body. We
propose an encoder-decoder architecture with a novel multi-branch decoder
designed to account for the varying uncertainty in 2D predictions. The
quantitative evaluation, on synthetic and real-world datasets, shows that our
strategy leads to substantial improvements in accuracy over state of the art
egocentric approaches. To tackle the lack of labelled data we also introduced a
large photo-realistic synthetic dataset. xR-EgoPose offers high quality
renderings of people with diverse skintones, body shapes and clothing,
performing a range of actions. Our experiments show that the high variability
in our new synthetic training corpus leads to good generalization to real world
footage and to state of theart results on real world datasets with ground
truth. Moreover, an evaluation on the Human3.6M benchmark shows that the
performance of our method is on par with top performing approaches on the more
classic problem of 3D human pose from a third person viewpoint.Comment: 14 pages. arXiv admin note: substantial text overlap with
arXiv:1907.1004
Multiscale understanding of tricalcium silicate hydration reactions
Tricalcium silicate, the main constituent of Portland cement, hydrates to produce crystalline calcium
hydroxide and calcium-silicate-hydrates (C-S-H) nanocrystalline gel. This hydration reaction is poorly
understood at the nanoscale. The understanding of atomic arrangement in nanocrystalline phases is
intrinsically complicated and this challenge is exacerbated by the presence of additional crystalline
phase(s). Here, we use calorimetry and synchrotron X-ray powder diffraction to quantitatively follow
tricalcium silicate hydration process: i) its dissolution, ii) portlandite crystallization and iii) C-S-H
gel precipitation. Chiefly, synchrotron pair distribution function (PDF) allows to identify a defective
clinotobermorite, Ca11Si9O28(OH)2.8.5H2O, as the nanocrystalline component of C-S-H. Furthermore,
PDF analysis also indicates that C-S-H gel contains monolayer calcium hydroxide which is stretched
as recently predicted by first principles calculations. These outcomes, plus additional laboratory
characterization, yielded a multiscale picture for C-S-H nanocomposite gel which explains the observed
densities and Ca/Si atomic ratios at the nano- and meso- scales.This work has been supported by Spanish MINECO through BIA2014-57658-C2-2-R, which is co-funded by
FEDER, BIA2014-57658-C2-1-R and I3 (IEDI-2016-0079) grants. We also thank CELLS-ALBA (Barcelona,
Spain) for providing synchrotron beam time at BL04-MSPD beamline
Collapse of the Mott gap and emergence of a nodal liquid in lightly doped SrIrO
Superconductivity in underdoped cuprates emerges from an unusual electronic
state characterised by nodal quasiparticles and an antinodal pseudogap. The
relation between this state and superconductivity is intensely studied but
remains controversial. The discrimination between competing theoretical models
is hindered by a lack of electronic structure data from related doped Mott
insulators. Here we report the doping evolution of the Heisenberg
antiferromagnet SrIrO, a close analogue to underdoped cuprates. We
demonstrate that metallicity emerges from a rapid collapse of the Mott gap with
doping, resulting in lens-like Fermi contours rather than disconnected Fermi
arcs as observed in cuprates. Intriguingly though, the emerging electron liquid
shows nodal quasiparticles with an antinodal pseudogap and thus bares strong
similarities with underdoped cuprates. We conclude that anisotropic pseudogaps
are a generic property of two-dimensional doped Mott insulators rather than a
unique hallmark of cuprate high-temperature superconductivity
Evidence of an improper displacive phase transition in CdReO via time-resolved coherent phonon spectroscopy
We have used a combination of ultrafast coherent phonon spectroscopy,
ultrafast thermometry, and time-dependent Landau theory to study the inversion
symmetry breaking phase transition at K in the strongly spin-orbit
coupled correlated metal CdReO. We establish that the structural
distortion at is a secondary effect through the absence of any softening
of its associated phonon mode, which supports a purely electronically driven
mechanism. However, the phonon lifetime exhibits an anomalously strong
temperature dependence that decreases linearly to zero near . We show that
this behavior naturally explains the spurious appearance of phonon softening in
previous Raman spectroscopy experiments and should be a prevalent feature of
correlated electron systems with linearly coupled order parameters.Comment: 5 pages main text, 5 figures, 7 pages supplementary informatio
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